Power End Housing for Plunger Pump and Plunger Pump Including Power End Housing

Abstract

The present disclosure provides a power end housing for a plunger pump and a plunger pump including the power end housing. The power end housing includes: an integrated crankcase (100), where the crankcase (100) includes a plurality of bearing seats (101) and a plurality of support vertical plates (102), the support vertical plates (102) are configured to support the bearing seats (101), the support vertical plates (102) are spaced apart in an axial direction of the bearing seats (101), and the crankcase (100) includes a first reinforcing rib (103) between every two support vertical plates (102), wherein an angle between a direction of a maximum resultant force on the bearing seats (101) and an axial direction of a plunger of the plunger pump is βmax, an angle between the first reinforcing rib (103) and the axial direction of the plunger is a first angle, and the first angle is greater than or equal to 0.8 βmax and less than or equal to 1.2 βmax. According to the present disclosure, a service life of the plunger pump is increased.

Description

TECHNICAL FIELD

The present disclosure relates to the field of oil and gas extraction technologies, and in particular, to a power end housing for a plunger pump, particularly an integrated crankcase, and a plunger pump including the power end housing.

BACKGROUND

A reciprocating pump is commonly used in mining and oilfield application such as hydraulic fracturing. During fracturing, fracturing liquid (namely, cement, mud, fracturing sand, and other materials) is pumped into a wellbore at a high pressure to fracture a formation. One type of pump commonly used in the hydraulic fracturing is a fracturing pump, such as the fracturing pump described in U.S. Pat. No. 11,204,030 B2 of SPM and US 2022/0163034 A1 of KERR.

The fracturing pump is widely used in the petroleum industry as an important device that may increase oil and gas production. Over recent years, use of a fracturing device has helped continuously increase oilfield productivity. The fracturing device plays an important role in increasing production of some old oil fields in the middle and late stages, developing new oil fields, and in the development of emerging shale gas.

The fracturing pump is mainly composed of three subsystems: a power end, a hydraulic end, and a gear reduction case. The power end is structurally responsible for connecting two subsystems: a reduction case and a hydraulic end valve case, and functionally responsible for converting rotating mechanical energy transmitted from the reduction case into reciprocating mechanical energy, to drive a liquid suction and discharge function of the hydraulic end; a function of the hydraulic end is to pressurize low-pressure liquid to high-pressure liquid, and output the high-pressure liquid to a high-pressure manifold; and a function of the reduction case is to convert a high speed and low torque input by a power source (including but not limited to a diesel engine, a motor, a turbine, and the like) into a low speed and high torque through multi-stage reduction, and then input the low speed and high torque into the power end. Due to the limitation of space layout and the need to facilitate disassembling, assembling, and maintenance, most fracturing pumps have a horizontal in-line structure, to be specific, a center line of reciprocating components of the power end is horizontally arranged, and parallel to a central axis of a pressurized cavity.

A power end assembly is mainly composed of a housing, a crank connecting rod assembly, a crosshead tie rod assembly, and a lubrication system. A power end housing includes a crankcase and a crosshead case. The crankcase is connected to one end of the crosshead case, and an other end of the crosshead case is connected to a pump head body of the hydraulic end through a connecting apparatus. For a five-cylinder fracturing pump, a crankshaft is usually an integral structure with six supports and five cranks, supported by a heavy-duty cylindrical roller bearing, and is a statically indeterminate structure. There are oil passages that are drilled in communication with each other at each crank, to lubricate a connecting rod bearing bush.

As a key component of the fracturing pump, the power end housing is configured to carry all components of the power end, and carry all loads caused by all the components of the power end during operation. Therefore, good mechanical performance of the housing has a decisive impact on a service life of the fracturing pump. According to different composition manners of a housing structure, the power end housing may be divided into an integral structure and a split structure.

Currently, an integral power end housing on the market often uses a tailor-welded structure to meet function and performance requirements of the fracturing pump. The power end housing is mostly welded by using a high-strength alloy plate. Welding is completed after performing spot welding on a basic frame and an overall frame, performing preheating and welding on a frame assembly, performing heat processing (stress relief annealing), rough machining, and defect polishing, and performing overall welding again, weldment heat processing, and detection.

The split power end housing is usually made by partial welding. For the split power end housing, in addition to tailor welding, very few manufacturers use split casting. For example, US 2022/0163034 A1 of KERR uses split casting. However, this design also has some shortcomings: Although a large amount of weight reduction design is used, advantages of casting are not fully utilized, and an overall housing is still too heavy, making it inconvenient to transport and assemble. Positions and a quantity of support points of an entire pump are improperly designed, resulting in concentrated stress on the support points, and a strength and stiffness of the entire pump are prone to failure. A span of the power end is too large, components are scattered, and a crosshead structure is designed in a large size, resulting in a great torque on the power end during operation, which reduces the service life of the fracturing pump; overall stiffness of a power end assembly is mostly provided by a plurality of groups of bolts and connecting rods, and the overall structural stiffness is poor; and overall sealing of the power end is poor, and oil and gas leakage is prone to occur.

A good overall structure and layout design of the power end determines that the stiffness and the strength of the pump may meet an operating requirement. Based on this, the hydraulic end and the reduction case may operate smoothly.

As oilfield production conditions at home and abroad develop toward a high pressure and a large displacement, an increasingly high requirement is placed on reliability of a fracturing pump structure, case of maintenance, and lightweight design. To adapt to a development trend of future fracturing operation, the fracturing pump is developing toward a direction of a high pressure, a high power, a large displacement, a compact structure, a long working time, and a low maintenance cost.

Usually, an application scenario and an operating environment of the fracturing pump are very harsh. Road conditions are complicated when transporting to and from a well site. The housing is subject to vibration and impact due to continuous bumps of a vehicle. During long-time and high-load operation in the fracturing operation, the pump delivers liquid or slurry with a pressure up to about 10,000 to 20,000 psi, and the power end housing is subject to a high-pressure periodic pulse load. Due to such extreme operating conditions, and poor impact resistance of the welded power end housing, a crack is prone to form near a weld, which in turn causes the housing to crack, eventually leading to failure of a support function, affecting efficiency of the fracturing operation, and even causing a safety hazard. The currently existing welded power end housing has a service life of 2,000 to 3,000 hours at most. Even after a single failure is repaired, the currently existing welded power end housing can hardly have a service life longer than a service life (5,000 hours) designed in a system.

The plunger pump is one of core components of an oilfield pumping device, and reciprocates in a cylinder by using a plunger, causing an operating volume in the cylinder to alternately increase and decrease, to transport operating liquid.

As an operating requirement for the current oilfield is getting increasingly high, and working conditions are getting increasingly worse, a requirement for a power, a pressure, and a displacement of the plunger pump is constantly increasing, and a continuous operating time is also continuously extended. Therefore, in the related art, an increasingly high requirement is put forward on stability of the plunger pump such as a strength of the plunger pump that may affect the service life of the plunger pump and reliability of connection between components. For example, to resolve the problem described above in the related art that an insufficient strength of the plunger pump results in an insufficient service life, it is urgent to develop a novel plunger pump with a high strength and high stability and reliability to resolve the current operating requirement.

SUMMARY

To extend a service life of a plunger pump, stability and a strength of the plunger pump need to be further improved, especially connection reliability between components of the plunger pump and a mechanical strength of a housing of the plunger pump. In particular, in the plunger pump, the connection reliability or support reliability between a bearing seat in a crankcase and a bearing supported by the bearing seat is also an important aspect to measure the stability of the plunger pump. On one hand, when a width of the bearing seat is greater than a width of the bearing supported by the bearing seat, a wide bearing seat occupies more internal space of the crankcase, and further increases an overall weight of the crankcase, which is not conducive to lightweight design of the plunger pump; and on the other hand, when the width of the bearing seat is less than the width of the bearing supported by the bearing seat, the bearing seat cannot reliably support the bearing, resulting in poor support reliability. Appropriate width design is required between the bearing seat and the bearing supported by the bearing seat to maximize reliability of connection between the bearing seat and the bearing supported by the bearing seat.

To resolve the technical problems mentioned above, and improve the stability and the strength of the plunger pump, the inventor of this application designs a new form of fracturing pump power end housing, which has a small overall weight, a greatly improved strength, small deformation at key matching parts, and improved connection reliability between components, so that properties of bending and torsion resistance and cushioning and vibration resistance are better, and sensitivity to notch resistance is low. In addition, a manufacturing procedure is greatly simplified, and time, labor, and raw material costs are reduced. Coupled with the housing improvement and optimization of various pump components, a disruptive fracturing pump device may be formed.

According to a first aspect of the present disclosure, a power end housing for a plunger pump is provided, including: an integrated crankcase, where the crankcase includes a plurality of bearing seats and a plurality of supporting structural members, the supporting structural members are configured to support the bearing seats, the supporting structural members are spaced apart in an axial direction of the bearing seats, and the crankcase includes a first reinforcing rib between every two supporting structural members, where an angle between a direction of a maximum resultant force on the bearing seats and an axial direction of a plunger of the plunger pump is βmax, an angle between the first reinforcing rib and the axial direction of the plunger is a first angle, and the first angle is greater than or equal to 0.8 βmax and less than or equal to 1.2 βmax.

Further, the first reinforcing rib is arranged at least on a front end surface and/or a rear end surface of the crankcase, the front end surface is a surface of the crankcase on a side connected to a crosshead case, and the rear end surface is a surface of an opposite side of the front end surface.

Further, a group of first reinforcing ribs are separately arranged on the front end surface and the rear end surface, and the first reinforcing ribs in each group are symmetrical to each other relative to the axial direction of the plunger of the plunger pump.

Further, the group of first reinforcing ribs arranged on the front end surface and the group of first reinforcing ribs arranged on the rear end surface are symmetrical to each other relative to a vertical centerline of the bearing seats.

Further, each group of first reinforcing ribs includes two first reinforcing ribs, and an angle between extending directions of the two first reinforcing ribs is greater than or equal to 1.8 βmax and less than or equal to 2.2 βmax.

Further, the crankcase further includes a plurality of second reinforcing ribs between every two supporting structural members, and extending directions of the second reinforcing ribs pass through a center of a circle of the bearing seat.

Further, the plurality of second reinforcing ribs are symmetrically arranged along seat holes of the bearing seat.

Further, the plurality of second reinforcing ribs are arranged on an upper side and a lower side of the bearing seat, where three upper side reinforcing ribs are arranged on the upper side and two lower side reinforcing ribs are arranged on the lower side, and the two lower side reinforcing ribs are separately located on two sides of a bottom portion oil return port without interfering with the bottom portion oil return port.

Further, a transition bevel is arranged between the first reinforcing rib and/or the second reinforcing rib and the supporting structural member, and there is a transition fillet between the bevel and the supporting structural member.

According to a second aspect of the present disclosure, a power end housing for a plunger pump is provided, including: an integrated crankcase, where the crankcase includes a plurality of bearing seats and a plurality of supporting structural members, the supporting structural members are configured to support the bearing seats, and the supporting structural members are spaced apart in an axial direction of the bearing seats, where a width of the bearing seat is defined by a width of a bearing imposed on the bearing seat.

Further, the bearing seat includes two end portion bearing seats located at two ends of the crankcase and several middle-section bearing seats, and the middle-section bearing seats are located between the two end portion bearing seats, where a width of each middle-section bearing seat is greater than a width of each of the two end portion bearing seats.

Further, a width of one of the two end portion bearing seats located on a side of a reduction case connection side of the crankcase is greater than a width of an other of the two end portion bearing seats.

Further, spacings between the supporting structural members are different, and relative to a center of a length direction of the crankcase, the spacings between the supporting structural members are set to be symmetrical to each other, where the length direction is parallel to the axial direction of the bearing seat.

Further, according to the power end housing in the first aspect and the second aspect of the present disclosure, weight-reducing grooves are provided on the supporting structural member.

Further, according to the power end housing in the first aspect and the second aspect of the present disclosure, hoisting point bosses are arranged on a top portion of the supporting structural member, and a transition fillet is arranged at a joint between the hoisting point boss and a case body of the crankcase.

Further, according to the power end housing in the first aspect and the second aspect of the present disclosure, a bottom portion of the crankcase includes legs, and the legs are configured to support the crankcase.

Further, according to the power end housing in the first aspect and the second aspect of the present disclosure, a plurality of first threaded holes are provided on a surface of a side of the crankcase close to a crosshead case, and the first threaded holes are configured to connect the crankcase and the crosshead case through first bolts.

Further, according to the power end housing in the first aspect and the second aspect of the present disclosure, the crankcase is integrally cast.

According to a third aspect of the present disclosure, a plunger pump is provided, where the plunger pump includes the power end housing according to the first aspect and the second aspect of the present disclosure.

Further, the plunger pump further includes a hydraulic end housing, where the power end housing further includes a crosshead case, and the hydraulic end housing, the crosshead case, and the crankcase are sequentially connected, where first threaded holes penetrate from the hydraulic end housing to the crankcase, and first bolts connect the hydraulic end housing, the crosshead case, and the crankcase together through the first threaded holes.

The technical solution adopted in the present disclosure can achieve the following beneficial effects:

According to the power end housing disclosed in the present disclosure, the connection reliability and the support reliability between the bearing seat and the bearing supported by the bearing seat may be improved, the stability of the plunger pump may be improved, and an impact force of the plunger pump on the crankcase may be effectively resisted, thereby avoiding a risk of relative deformation of the supporting structural members, and promoting the power end housing to have greater strength and stiffness. A service life of the power end housing disclosed according to the present disclosure exceeds 8,000 hours, and may even exceed 10,000 hours, which is about twice or more than twice the service life of the power end housing in the related art.

BRIEF DESCRIPTION OF THE DRAWINGS

Accompanying drawings described herein are used for providing further understanding about the present disclosure, and constitute one portion of the present disclosure. Exemplary embodiments of the present disclosure and descriptions thereof are used for explaining the present disclosure, and do not constitute an inappropriate limitation on the present disclosure. In the accompanying drawings,

FIG. 1 is a perspective view of an integrated crankcase according to an embodiment of the present disclosure, in which a front end surface of the crankcase is shown;

FIG. 2 is another perspective view of an integrated crankcase according to an embodiment of the present disclosure, in which a rear end surface of the crankcase is shown;

FIG. 3 is a cross-sectional view of a crankcase provided with a crankshaft;

FIG. 4 is a partially cutaway perspective view of a crankcase provided with a crankshaft;

FIG. 5 is a force curve diagram of bearing seats at two ends and a main bearing;

FIG. 6 is a force curve diagram of a middle-section bearing seat and a main bearing;

FIG. 7 is a perspective view of a crankcase, in which hoisting point bosses and oil and gas separator bosses are shown;

FIG. 8 is a partially enlarged view of a hoisting point boss part;

FIG. 9 is a perspective view of a crankcase displaying positions of process through holes and bearing baffle threaded holes;

FIG. 10 is a perspective view of a crankcase displaying positions of process through holes and bearing baffle threaded holes on a cross section of a supporting structural member;

FIG. 11 is a partially enlarged view of a reinforcing rib between supporting structural members;

FIG. 12 is a schematic diagram and a force analysis diagram of a crank connecting rod structure of a simplified kinematic structure of a crankshaft and a plunger;

FIG. 13 shows arrangement of reinforcing ribs and a diagram of a connecting rod swing angle;

FIG. 14 is a plan view showing a front end surface of a crankcase, connecting rod through holes, and oil drain through holes, and an enlarged view of the oil drain through hole;

FIG. 15 is a perspective view showing a crankcase and a crosshead case that are jointly connected to a chassis, in which a plurality of legs of the crankcase are shown;

FIG. 16 is a partially perspective view of a crankcase showing a plurality of legs arranged at a bottom portion of a supporting structural member;

FIG. 17 is a perspective view of a crankcase showing transverse integrated legs and longitudinal integrated legs;

FIG. 18 is a partially enlarged view of a leg;

FIG. 19 is a cross-sectional view of a side of a crankcase showing an entire bearing seat hole;

FIG. 20 is a cutaway perspective view of a crankcase, in which a partially cutaway view of a plurality of oil and gas separator bosses arranged on a top portion of a crankcase is shown;

FIG. 21 is a perspective view of a crankcase seen from below;

FIG. 22 is a perspective view of a state in which an oil return port cover plate is not mounted on a crankcase;

FIG. 23 and FIG. 24 separately show each process window on a crankcase;

FIG. 25 shows a state in which a cover plate is mounted on a rear end surface of a crankcase;

FIG. 26 is a perspective view before a crankcase and a crosshead case are connected by bolts;

FIG. 27 is a perspective view from another angle before a crankcase and a crosshead case are connected by bolts;

FIG. 28 is a side view of a crankcase 100 showing two threaded holes on a cross section and a partially enlarged view of two threaded holes;

FIG. 29 is a cross-sectional view of a crankcase and a crosshead case that are connected together by two bolts;

FIG. 30 is a partially enlarged view of connection by two bolt shown in FIG. 29;

FIG. 31 is a partial view of one-to-one arrangement of two bolts;

FIG. 32 is a partial view of one-to-two arrangement of two bolts;

FIG. 33 is a plan view showing a relationship between arrangement positions of two bolts;

FIG. 34 shows a sealing groove provided on a connecting end surface between a crankcase and a crosshead case;

FIG. 35 is a schematic diagram of a crankshaft rotation angle and a pressure angle of a main bearing;

FIG. 36 is a schematic diagram of a crankshaft rotation angle and a resultant force of a main bearing; and

FIG. 37 is a schematic diagram of a pressure angle and a resultant force of a main bearing.

LIST OF REFERENCE NUMERALS

100: Crankcase; 200: crosshead case; 101: bearing seat; 102: support vertical plate (or supporting structural member); 103, 103′: reinforcing rib; 104: top portion; 105: bottom portion; 106: front end surface; 107: rear end surface; 109: weight-reducing groove; 110: hoisting point boss; 111: hoisting point; 112: process through hole; 113: threaded hole; 114: aluminum plug; 115: transition bevel; 116: transition fillet; 117: connecting rod through hole; 118: oil drain through hole; 119, 119′, 119″: leg; 120: bevel; 121: weight-reducing groove; 122: cover plate; 123: leg bottom portion contact surface; 124: anchor threaded hole; 125: oil and gas separator boss; 126: oil return port; 127: oil return cover plate mounting boss; 128: integrated cover plate; 129, 129′: process window; 130: recessed platform; 131: first bolt; 132: second bolt; 133: sealing groove; 141: first threaded hole; 142: second threaded hole; 211: crosshead cavity; and 500: chassis.

DETAILED DESCRIPTION

To illustrate the objectives, technical solutions, and advantages of the present disclosure, the technical solutions of the present disclosure will be described below with reference to specific embodiments of the present disclosure and the accompanying drawings. It is clearly that described embodiments are merely some but not all of embodiments of the present disclosure. All other embodiments obtained by a person of ordinary skill in the art based on embodiments of the present disclosure without creative efforts shall fall within the protection scope of the present disclosure.

The following describes the technical solution disclosed in each embodiment of the present disclosure in detail with reference to the accompanying drawings. For an objective of simplicity, reference numbers of various components are not necessarily shown in each figure. Generally, for an objective of emphasis, some accompanying drawings only show reference numerals of related components described with reference to the accompanying drawing in the specification, and related numerals of other components are omitted. However, the same reference numerals are used in different accompanying drawings for the same components. For distinguishing identical or similar components and convenience of description, appropriate superscript suffixes of single quotation marks are sometimes added to the reference numerals. This is only for convenience of description, and when there is no need to distinguish the identical or similar components, the suffix can be omitted.

Embodiments of the present disclosure disclose a power end housing for a plunger pump. The power end housing is a mounting base of a power end of the plunger pump. The power end of the plunger pump is responsible for connecting a reduction case and a hydraulic end valve case, and is responsible for converting rotating mechanical energy transmitted from the reduction case into reciprocating mechanical energy, to drive a liquid suction and discharge function of the hydraulic end. The disclosed power end housing includes a crankcase 100. Certainly, the power end housing may further include a crosshead case 200.

The crankcase 100 is configured to mount and support a crankshaft, and the crankshaft rotates in the crankcase 100. A crosshead cavity is provided in the crosshead case 200, a crosshead is mounted in the crosshead cavity, and a plunger drives the crosshead to reciprocate in the crosshead cavity.

Specifically, a transmission gear in the reduction case is connected to the crankcase 100, and the transmission gear in the reduction case drives the crankshaft to rotate. The crankshaft drives the plunger to reciprocate, and the crosshead follows the plunger to reciprocate in the crosshead cavity, thereby driving suction and discharge of liquid of a hydraulic end. The crosshead and the plunger may be equivalent to the same component.

FIG. 1 is a perspective view of an integrated crankcase 100 according to an embodiment of the present disclosure, particularly showing a front end surface 106 of a side of the crankcase 100 that is connected to a crosshead case 200; and FIG. 2 is another perspective view of an integrated crankcase 100 according to an embodiment of the present disclosure, particularly showing a rear end surface 107 of an opposite side of a side of the crankcase 100 that is connected to a crosshead case 200.

As shown in FIG. 1 and FIG. 2, the integrated crankcase 100 according to an embodiment of the present disclosure includes a plurality of bearing seats 101, a top portion 104, a bottom portion 105, a plurality of support vertical plates 102, and at least one (for example, more than one) reinforcing rib 103 located between the support vertical plates 102. FIG. 1 and FIG. 2 further show a front end surface 106 and a rear end surface 107 of the crankcase 100. The front end surface 106 is a surface of a side of the crankcase 100 that is connected to the crosshead case 100, and the rear end surface 107 is a surface of an opposite side of the front end surface 106. The integrated crankcase 100 may be formed by casting. The top portion 104 and the bottom portion 105 separately extend from one end to an other end in a length direction X of the crankcase 100 at an upper side and a lower side in a height direction Z of the crankcase 100. The front end surface 106 and the rear end surface 107 separately extend from one end to an other end in a length direction Y of the crankcase 100 at a front side and a rear side in a width direction Y of the crankcase 100. Each support vertical plate 102 is configured to support each bearing seat 101. The support vertical plates 102 are spaced apart in an axial direction of the bearing seat 101. A quantity of the support vertical plates 102 and a quantity of the bearing seats 101 are related to a quantity of cylinders of the plunger pump. A thickness of the bearing seat 101 is greater than a thickness of the support vertical plate 102 in the axial direction (e.g., x direction in FIG. 1). The support vertical plate 102 is configured to support the bearing seat 101. A main bearing is mounted on the bearing seat 101, and the main bearing is sleeved on the crankshaft. Therefore, the crankshaft exerts a reaction force exerted by the plunger pump on the crankshaft on the main bearing, and exerts the reaction force on the bearing seat 101 and the plurality of support vertical plates 102 through the main bearing. Therefore, a resultant force on the main bearing is a resultant force on the bearing seat 101. The reaction force of the plunger pump on the crankshaft is exerted on the plunger pump by the hydraulic end. The bearing seat 101 is configured to bear a radial load of the main bearing. Therefore, a width of the bearing seat 101 along the axial direction (e.g., x direction of FIG. 1) is set to be similar to a width of the bearing, to ensure reliable support. The plunger pump has various specifications. Therefore, the bearing that is used also has various specifications. Different bearings need to match different bearing seats. Therefore, the width of the bearing seat 101 is defined by the width of the bearing supported by the bearing seat 101. The support vertical plates 102 serve as a core frame of the entire crankcase 100. Proper arrangement of the support vertical plates 102 may ensure uniform stiffness of the housing of the plunger pump, and reliably support each bearing seat 101, thereby ensuring stable operation of the main bearing and a crankshaft connecting rod mechanism. A specific and proper arrangement solution of the support vertical plates 102 is described in detail below. The multiple support verticle support plates 102 may constitutes portions of a contiguously casted single-piece frame of the crankcase 100. The term “support verticle plates” may be alternatively referred to as “supporting structural members” of the crankcase 100.

Spacings between the supporting structural members 102 may be the same, and the spacings depend on sizes of pump components; or spacings between the end portion supporting structural members 102 at two ends of the crankcase 100 in a length direction Y are different from spacings between the middle-section supporting structural members 102, and the middle-section supporting structural member 102 is located between the end portion supporting structural members 102 located at two ends. For example, the spacing between the end portion supporting structural members 102 refer to a spacing between the two supporting structural members 102 on an outermost side at two ends in the length direction Y of the crankcase 100; or relative to a center of a length direction Y of the crankcase 100, the spacings between the supporting structural members 102 are set to be symmetrical to each other, and the length direction Y is parallel to an extending direction of an axis of the bearing seat 101; and proper arrangement of the supporting structural members 102 may effectively improve overall bending resistance stiffness of the crankcase 100, and suppress deformation of the housing of the plunger pump.

Several weight-reducing grooves 109 are provided on each supporting structural member 102 along a circumference of the bearing seat 101 on two sides of the bearing seat 101 in an axial direction; a depth of the weight-reducing groove 109 is determined according to a design requirement, and a starting edge and an ending edge of the weight-reducing groove 109 have transition fillets, where a position at which the weight-reducing groove 109 is cut from a surface of the supporting structural member 102 is the starting edge, and an edge formed by cutting the weight-reducing groove 109 is the ending edge; and a specific shape and extent of the weight-reducing groove 109 are affected by arrangement of reinforcing ribs 103, 103′. For example, the reinforcing ribs 103, 103′ may be arranged symmetrically in an up and down direction or arranged asymmetrically with a plunger axis of the plunger pump as a center. The reinforcing ribs 103, 103′ as described above are cast between the supporting structural members 102 (refer to FIG. 1). The weight-reducing grooves 109 provided on the supporting structural member 102 should be spaced apart away from the reinforcing ribs 103, 103′. As mentioned above, the integrated crankcase 100 of the present disclosure may be integrally cast. In this way, the weight-reducing groove 109 is also prepared in the integrally cast crankcase 100. The integrally cast weight-reducing groove 109 may greatly reduce machining procedures. A position and a shape of the weight-reducing groove 109 are not limited by a processing manner and may be flexibly arranged.

A diameter of the bearing seat 101 depends on a size of an outer ring of a bearing applied to the bearing seat 101. In an embodiment of the present disclosure, a diameter of each bearing seat 101 is the same; or seat holes of the bearing seats 101 located at two ends of the crankcase 100 in the length direction Y may be greater than seat holes of the middle-section bearing seats 101, and the middle-section bearing seats 101 are located between the bearing seats 101 at two ends. According to the design, it may be ensured that an outer ring of each bearing may be smoothly mounted from two sides to a corresponding bearing position after cooling and shrinking. After warming up and expanding, the outer ring forms an interference fit with a support surface of the bearing. A contact surface between the bearing seat 101 and the outer ring of the bearing requires additional machining procedures, including but not limited to boring and milling, to ensure geometric tolerance and surface roughness requirements of each bearing seat 101, thereby ensuring normal rotation of each bearing and crankshaft.

In an embodiment of the present disclosure, FIG. 3 and FIG. 4 separately show a cross-sectional view and a partially cutaway perspective view of a crankcase 100 provided with a crankshaft, in which a width t1 of each middle-section bearing seat 101 is the same, and a width t2 and a width t3 of the bearing seats 101 at two ends are less than the width t1 of the middle-section bearing seat 101. This is because a load (about 600 kN) on a connecting rod on a single-sided crank pin borne by crank journals 1 and 6 on two sides of the crankshaft is much less than a load (about 1200 kN) on a double-sided connecting rod that middle-section crank journals 2 to 5 need to bear. To reduce a weight of the housing of the plunger pump as much as possible, thicknesses of the crank journals 1, 6 on two sides are designed to be less. Therefore, a width of the bearing and the bearing seat 101 that support the crank journals 1, 6 on two sides of the crankshaft is less than a width of a middle-section bearing and the bearing seat 101. For conditions about a force on the main bearings at two ends and the middle-section main bearing, refer to a force curve in FIG. 5 and a force curve in FIG. 6 for details. Because shaft journals are in a one-to-one correspondence with each main bearing, for convenience, the main bearings corresponding to each shaft journal are given the same reference numerals. Refer to FIG. 5 and FIG. 6 for details.

It is worth noting that the width t2 and the width t3 of the bearing seats 101 at two ends are also slightly different. An end portion bearing seat 101 on the reduction case side requires additional positioning pin holes and threaded holes to position and fix a connecting flange of a reduction case body, and needs to withstand a torque and a load of the reduction case, such as a torque and a torsional impact load, a part of gravity of the reduction case, a vibration impact load of parallel-level and planetary-level meshing of the reduction case. Therefore, the thickness of the bearing seat 101 is designed to be t2>t3. A specific difference may be calculated according to a strength and stiffness design of the housing and determined according to statics and fatigue analysis. It is ensured that deformation values of all bearing seats 101 and deformation values of vertical plates on which the bearing seats 101 are located are similar. A concept of equal stiffness design is considered, to ensure stability and consistency of the overall stiffness of the housing and a matching gap. Alternatively, a width of each bearing seat 101 may be adjusted according to the design requirement, provided that the main bearing may be stably supported.

In addition, FIG. 7 is a perspective view of a crankcase 100. A hoisting point boss 110 for a hoisting point 111 is arranged on a top portion of a supporting structural member 102, and a cross-sectional shape of the hoisting point boss 110 is not limited. FIG. 8 is a partially enlarged view of a hoisting point boss 110. To meet a hoisting balance requirement, the hoisting point bosses 110 are arranged close to the supporting structural members 102 at two ends, and a quantity of hoisting point bosses 110 is greater than or equal to two. A transition fillet of a great size is arranged at a joint between the hoisting point boss 110 and a case body of a crankcase 100, which is conducive to improving a strength of a root portion of the hoisting point boss 110 and satisfying casting process; or the hoisting point boss 110 may not be arranged. Instead, a partially thickened structure is cast, provided that a hoisting condition may be met. That the hoisting point boss 110 is not arranged means that a regular platform or column is not cast at a hoisting point, and a strength of the hoisting point is ensured only through accumulation and thickening (which may be irregular) of local materials. A height and a thickness of the hoisting point boss 110 are related to a size of a hoisting eye bolt. The greater the weight of the case body, the greater the size of the hoisting eye bolt required to increase a tensile strength, and thus the higher and wider hoisting eye boss needs to be cast. In addition, upper surfaces of the hoisting point bosses 110 of the whole pump are on the same plane, thereby ensuring stable hoisting and preventing toppling.

In addition, process through holes 112 provided in a circumferential direction along an axis of the bearing seat 101 are provided on the end portion supporting structural members 102 at two ends of the crankcase 100 in a length direction Y, and the process through holes 112 are configured to process middle-section bearing outer ring baffle threaded holes 113. FIG. 9 and FIG. 10 separately show a perspective view of a crankcase 100 displaying positions of process through holes 112 and positions of bearing baffle threaded holes 113 and a perspective view of a crankcase 100 displaying positions of process through holes 112 and positions of bearing baffle threaded holes 113 on a cross section of a supporting structural member 102. Positions and a quantity of process through holes 112 are determined by a layout solution of bearing baffles. To ensure reliable pressing and positioning, each bearing baffle is fixed by at least two bolts, and one side of the outer ring of the bearing is fixed by at least three bearing baffles. In addition, it is ensured that each bearing baffle is close to process windows on two sides for case of mounting. Therefore, correspondingly, at least two process through holes 112 are grouped into a group, corresponding to one baffle, and at least three groups of process through holes 112 are provided in a circumferential direction. Each group of process through holes 112 should be as evenly arranged as possible and close to process windows on two sides. To ensure oil and gas sealing in the crankcase 100, each process through hole 112 needs to be sealed tightly with an aluminum plug 114; or may be replaced with any material that may be inserted into a through hole and ensure sealing without damaging the body, including but not limited to rubber, plastic, and the like.

In addition, several reinforcing ribs 103, 103′ are arranged between every two supporting structural members 102 along a circumference of the bearing seat 101. Refer to FIG. 1, the reinforcing ribs 103, 103′ are configured to limit deformation and displacement of each supporting structural member 102. As mentioned above, the crankcase 100 may be integrally formed, such as integrally cast. Therefore, the reinforcing ribs 103, 103′ may also be integrally formed in the integral cast process of the crankcase 100. Compared with spliced reinforcing ribs, the integrally cast reinforcing ribs 103, 103′ have higher bending and torsion resistance and better cushioning and vibration absorption properties. Therefore, compared with the spliced reinforcing ribs, the integrally cast reinforcing ribs 103, 103′ have a more stable support capability, may significantly improve stiffness of the overall crankcase 100, and suppress deformation and vibration of the housing.

In addition, FIG. 11 is a partially enlarged view of a reinforcing rib 103 between supporting structural members 102. A transition bevel 115 is arranged between the reinforcing rib 103 and the supporting structural member 102, and there is a transition fillet 116 between the bevel 115 and a housing of a plunger pump, such as the supporting structural member 102. A main objective is to improve bending resistance strength of a root portion of the reinforcing rib 103, and the arrangement of the bevel 115 is conducive to satisfying casting process; and a form of the bevel 115 is not limited, and the bevel 115 may be set into a bevel or an arc shape (equal curvature or variable curvature) as required.

Arrangement of the reinforcing ribs 103, 103′ is described in detail below with reference to FIG. 12 and FIG. 13. FIG. 12 is a schematic diagram and a force analysis diagram of a crank connecting rod structure of a simplified kinematic structure of a crankshaft and a plunger; and FIG. 13 shows arrangement of reinforcing ribs 103, 103′ and a diagram of a connecting rod swing angle. A crankshaft drives the plunger to reciprocate. Therefore, a movement process of the crankshaft and the plunger at a power end may be simplified into a force analysis diagram shown on a right side in FIG. 12. According to the force analysis on the right side in FIG. 12, a resultant force on a main bearing may be obtained as F1ⁿ=F+F_c, where F represents a resultant force of a hydraulic force+a reciprocating inertial force+a friction force on an axial direction of the plunger, and F_c represents a support force of the plunger in a vertical direction. An angle between a direction of the resultant force F1″ and the axial direction of the plunger is β. An angle between a direction of the maximum resultant force F1″ and the axial direction of the plunger is βmax. According to the diagram on the right side in FIG. 12, by decomposing forces at a point A, a point B, and a point O, the formula F1ⁿ=F+F_c for the resultant force on the main bearing is obtained.

Meaning of each point in the figure is: O—a crankshaft center; A—a connecting rod small end hole center (crosshead pin rotation center); and B—a connecting rod big end hole center (crank pin rotation center).

Meaning of each force: Point A: F—a resultant force of a hydraulic force on a plunger in an axial direction+a reciprocating inertia force+a friction force; F_c—a support force of a plunger (crank pin) in a vertical direction; F₁—a connecting rod positive force;

point B: F_t—a connecting rod tangential force; F_n—a connecting rod radial force; and F₁′—connecting rod positive force→when converted to the point O, the connecting rod positive force is a resultant force F₁ⁿ on a bearing seat 101. After being transmitted to the crank pin through the connecting rod body, the connecting rod positive force F₁ is F₁′, and is decomposed into the connecting rod radial force F_n and the connecting rod tangential force F_t at the point B in a direction of a line connecting the crank pin and the crankshaft rotation center and a vertical direction of a line connecting the crank pin and the crankshaft rotation center, and after being transmitted to the point O, the connecting rod positive force F₁ is F_n′ and F_t′, and the resultant force is F₁″.

The following additional descriptions are provided regarding forces and movement of the point A, the point B, and the point O.

The plunger reciprocates in the axial direction, and a resultant force F transmitted to the crosshead is decomposed at the point A (crosshead pin) into the support force F_c of the plunger in the vertical direction and the connecting rod positive force F₁ in a vertical direction of the crosshead and a connecting rod direction; and after being converted to the point O, the support force F_c of the plunger in the vertical direction is the support reaction force F_c′ on the bearing seat. After being converted to the point O, the resultant force F of the plunger in the axial direction is the force F′ of the plunger in the axial direction on the bearing seat. The resultant force of F_c′ and F′ at the point O is the resultant force F₁ⁿ on the bearing seat, that is, F₁ⁿ=F+F_c.

After being transmitted to the crank pin through the connecting rod body, the connecting rod positive force F₁ at the point A is F₁′, and is decomposed into the connecting rod radial force F_n and the connecting rod tangential force F_t at the point B in a direction of a line connecting the crank pin and the crankshaft rotation center and a vertical direction of a line connecting the crank pin and the crankshaft rotation center, and after being transmitted to the point O, the connecting rod positive force F₁ is F_n′ and F_t′, and the resultant force is F₁ⁿ.

Specifically, according to a movement process of the crankshaft and the plunger at the power end, a movement structure of the crankshaft and the plunger is simplified into a crank connecting rod structure. As shown in the diagram on the left side in FIG. 12, a trigonometric function equation and a connecting rod swing angle β=arcsin[λ*sin φ] in a motion equation are constructed, where φ is a crankshaft rotation angle. An extreme value of the connecting rod swing angle depends on a ratio λ of a crank diameter to a length of a connecting rod. λ is a ratio of a diameter of the crankshaft to a length of the plunger. Therefore, λ is a constant. According to calculation, a displacement equation of the plunger is obtained

$x=r\left[\left(1+\frac{1}{\lambda }\right)-\cos \phi -\frac{{\left(1-{\lambda }^2\sin {\phi }^2\right)}^{\frac{1}{2}}}{\lambda }\right].$

Then, a pressure fluctuation equation of a hydraulic end against the plunger is derived according to the displacement equation of the plunger:

$P=\{\begin{array}{cc}\mathrm{p\_in}+\frac{x\left(\mathrm{p\_out}-\mathrm{p\_in}\right)}{\frac{s\mathrm{pr}}{\eta }}& 0\le \phi <\mathrm{\beta \_up}\\ \mathrm{p\_out}& \mathrm{\beta \_up}\le \phi \le \alpha \\ \left(1-\frac{\left(s-x\right)}{\frac{s\mathrm{pr}}{\eta }}\right)·\left(\mathrm{p\_out}-\mathrm{p\_in}\right)+\mathrm{p\_in}& \alpha <\phi \le \mathrm{\beta \_down}+\alpha \\ \mathrm{p\_in}& \mathrm{\beta \_down}+\alpha <\phi \le 360\end{array}:,$

where p represents a pressure in a cavity of the hydraulic end, and p_in represents a hydraulic supply pressure at an inlet of the hydraulic end; p_out represents a discharge pressure of the hydraulic end; s represents a stroke, where s is displacement of the plunger pump from a top dead center to a bottom dead center, namely a distance from a point A′ to a top dead center A″ in the diagram on the left side in FIG. 12; x represents displacement of the plunger, which refers to moving displacement of the plunger; pr represents a compressibility percentage of liquid under a specific pressure; η represents volumetric efficiency; β_up represents a crankshaft rotation angle corresponding to a process in which the pressure in the cavity of the hydraulic end changes from a low pressure to a high pressure; β_down represents a crankshaft angle corresponding to a pressure relief process in which the pressure in the cavity of the hydraulic end is changes from a high pressure to a low pressure; and α represents a top dead center angle, and the top dead center may be a position shown as B″ in the diagram on the left side in FIG. 12. According to the foregoing formula, the reaction force of the hydraulic end on the plunger may be obtained. Therefore, the hydraulic force on the plunger in the axial direction may be obtained according to the pressure p in the cavity of the hydraulic end. Then the resultant force on the main bearing is calculated according to the formula force F₁ⁿ=F+F_c, and a direction of the resultant force on the main bearing may be obtained. Then an angle between the direction of the resultant force on the main bearing and the axial direction of the plunger may be obtained, and then β may be obtained.

According to a moment of inertia formula

$1=\frac{b{h}^3}{12}$

of a center of a rectangular cross section, b is a width of the rectangular cross section, and h is a height of a rectangular structural surface.

When a length direction of the rectangular cross section is close to a direction of a force, a bending moment value of a rectangular beam is maximum. According to a moment of inertia integral formula and a simulation result, a moment of inertia of the rectangular beam still does not decrease significantly in a rotation angle ±20%. Therefore, when reinforcing design is performed on the crankcase 100, an angle between an extending direction of the first reinforcing rib 103 and the axial direction of the plunger is greater than or equal to 0.8 βmax and less than or equal to 1.2 βmax. βmax is an angle between a direction of a maximum resultant force on the bearing seat and the axial direction of the plunger of the plunger pump.

As mentioned above, the crankshaft exerts a reaction force exerted by the plunger pump on the crankshaft on the main bearing, and exerts the reaction force on the bearing seat 101 and the plurality of supporting structural members 102 through the main bearing. Therefore, a resultant force on the main bearing is a resultant force on the bearing seat 101. An angle between the resultant force and the axial direction of the plunger is β, and a maximum value of the connecting rod swing angle is βmax. Arrangement of the reinforcing ribs 103, 103′ is divided into two types: First, an extending direction of the first reinforcing rib 103 does not pass through a center of a circle of the bearing seat 101, and an angle between the extending direction of the first reinforcing rib 103 and the axial direction of the plunger is greater than or equal to 0.8 βmax and less than or equal to 1.2 βmax. The reinforcing ribs 103, 103′ are arranged up, down, left, and right along seat holes of the bearing seat 101, to be specific, a plurality of first reinforcing ribs 103 are arranged, which may effectively resist an impact force of the plunger pump on the crankcase 100, improve the strength and the stiffness of the supporting structural member 102, and strengthen the stiffness and the strength between the supporting structural member 102 and the bearing seat 101, thereby reducing a risk of cracking of the crankcase 100.

In the solution disclosed in this application, the first reinforcing rib 103 is arranged in a specific range of the angle between the direction of the resultant force on the bearing seat 101 and the axial direction of the plunger of the plunger pump, so that an impact force of the plunger pump on the crankcase 100 may be effectively resisted, thereby avoiding a risk of relative deformation of the supporting structural member 102, and promoting the power end housing to have a greater strength and greater stiffness.

In addition, the extending direction of the first reinforcing rib 103 is in an angle of ±20% relative to the direction of the maximum resultant force on the crankshaft. Therefore, a cross-sectional moment of inertia of the reinforcing rib is increased, thereby reducing relative deformation between the supporting structural members 102, and further reducing a risk of extrusion damage to an inner ring and an outer ring of the main bearing or wear of rollers.

FIG. 35 is a schematic diagram of a crankshaft rotation angle and a pressure angle of a main bearing. The pressure angle of the main bearing is β mentioned above. It may be learnt from FIG. 36 that the crankshaft rotation angle is in a range of 0° to 180°, the pressure angle is in a negative direction, and is maximum at 90°. The pressure angle is a positive value in a range of 180° to 360°, and is maximum at 270°.

FIG. 36 is a schematic diagram of a crankshaft rotation angle and a resultant force of a main bearing. It may be learnt from the accompanying drawings that the resultant force of the main bearing has obvious sudden changes between the crankshaft rotation angle ranging from 0° to 40° and the crankshaft rotation angle ranging from 180° to 200°.

FIG. 37 is a schematic diagram of a pressure angle and a resultant force of a main bearing. When the pressure angle is between 0° and 10°, the resultant force of the main bearing of the pressure angle is great.

Based on this, it may be learnt from FIG. 35, FIG. 36, and FIG. 37 that the pressure angle may be 10°. An angle between an extending direction of the first reinforcing rib and the axial direction of the plunger may be greater than or equal to 8° and less than or equal to 12°. Certainly, the pressure angle may be further another angle, which is not limited in this specification.

Further, as shown in FIG. 13, in another alternative or additional embodiment, a group of first reinforcing ribs 103 are separately arranged on the front end surface 106 and the rear end surface 107, and the first reinforcing ribs 103 in each group are symmetrical to each other relative to the axial direction of the plunger of the plunger pump. Further, the group of first reinforcing ribs 103 arranged on the front end surface 106 and the group of first reinforcing ribs 103 arranged on the rear end surface 107 are symmetrical to each other relative to a vertical centerline of the bearing seats 101. Specifically, the group of first reinforcing ribs 103 on the front end surface 106 of the crankcase 100 includes two front end reinforcing ribs 103. The two front end reinforcing ribs 103 are distributed on an upper side and a lower side of an axis of the crankshaft of the plunger pump and are symmetrical to each other relative to the axial direction of the plunger of the plunger pump, so that the angle between extending directions of the two front end reinforcing ribs 103 is a second angle. The second angle may be greater than or equal to 1.8 βmax and less than or equal to 2.2 βmax. The second angle is a θ angle in FIG. 13. Similarly, a group of first reinforcing ribs 103 on a rear end surface 107 of the crankcase 100 includes two rear end reinforcing ribs 103. The two rear end reinforcing ribs 103 are distributed on an upper side and a lower side of an axis of the crankshaft of the plunger pump and are symmetrical to each other relative to the axial direction of the plunger of the plunger pump, so that the angle between extending directions of the two front end reinforcing ribs 103 is also a second angle. The second angle may be greater than or equal to 1.8 βmax and less than or equal to 2.2 βmax. In this way, a force of the plunger on an outer ring of the main bearing may be better resisted, thereby avoiding a risk of the outer ring of the main bearing being squeezed and damaged or rollers being worn. Therefore, security and reliability of the power end housing are further improved. For example, the two front end reinforcing ribs 103 and the two rear end reinforcing ribs 103 may be arranged symmetrically relative to a vertical centerline of the bearing seat 101. In other words, the plurality of first reinforcing ribs 103 include the two front end reinforcing ribs 103 on the front end surface 106 of the bearing seat 101, and the two front end reinforcing ribs 103 are symmetrical to each other relative to the axial direction of the plunger of the plunger pump; and the plurality of first reinforcing ribs 103 further include the two rear end reinforcing ribs 103 on the rear end surface 107 of the bearing seat 101. The two rear end reinforcing ribs 103 are also symmetrical to each other relative to the axial direction of the plunger of the plunger pump. The front end surface 106 is a surface of a side of the crankcase 100 that is connected to the crosshead case 200, and the rear end surface 107 is a surface of an opposite side of the front end surface 106. Preferably, the two front end reinforcing ribs 103 and the two rear end reinforcing ribs 103 are symmetrical to each other relative to the vertical centerline of the bearing seat 101.

It should be noted that although different expressions of the first reinforcing rib 103, the front end reinforcing rib 103, and the rear end reinforcing rib 103 are used for case of description, this does not mean that the expressions are substantially different. When there is no need to distinguish the first reinforcing rib 103, the front end reinforcing rib 103, and the rear end reinforcing rib 103, the first reinforcing rib 103, the front end reinforcing rib 103, and the rear end reinforcing rib 103 may be collectively referred to as the first reinforcing rib 103.

According to the foregoing description, it may be learnt that an angle between a force direction of the main bearing and a movement direction of the plunger fluctuates between 0 and βmax. Therefore, bending resistance stiffness of the crankcase 100 are increased in a movement process of the crankshaft. In another alternative or additional embodiment, the power end housing may further include a plurality of 103′, and an extending direction of the second reinforcing rib 103′ passes through a center of a circle O of the bearing seat 101, as shown in FIG. 13. A plurality of second reinforcing ribs 103′ may be arranged symmetrically in an up and down direction along seat holes of the bearing seat 101, and a quantity of second reinforcing ribs 103′ is not limited, but positions of left and right process windows, the crosshead case 200, and a bottom portion oil return port need to be avoided, to improve stiffness of the bearing seat 101, and prevent rollers from bearing an excessive axial force. Theoretically, a quantity of second reinforcing ribs 103′ is not limited, but considering a support strength, a force, and a weight, the second reinforcing ribs 103′ and the first reinforcing ribs 103 are arranged uniformly as a whole. In this example, the second reinforcing ribs 103′ are designed to have three upper side reinforcing ribs 103′ on an upper side of the bearing seat 101 and two lower side reinforcing ribs 103′ on a lower side. The two lower side reinforcing ribs 103′ may be separately arranged on two sides of the bottom portion oil return port without interfering with the bottom portion oil return port. This is to be away from the bottom portion oil return port.

It should be noted that although different expressions of the second reinforcing rib 103′, the upper side reinforcing rib 103′, and the lower side reinforcing rib 103′ are used for ease of description, this does not mean that the expressions are substantially different. When there is no need to distinguish the second reinforcing rib 103′, the upper side reinforcing rib 103′, and the lower side reinforcing rib 103′, the second reinforcing rib 103′, the upper side reinforcing rib 103′, and the lower side reinforcing rib 103′ may be collectively referred to as the second reinforcing rib 103′.

In this example, a cross section of the reinforcing rib 103, 103′ is in a shape of a rectangle. Compared with other solid regular cross sections (such as a circle, a square, and the like) of the same area, a moment of inertia of a long-axis rectangular cross section is greater, which may ensure that the reinforcing rib 103, 103′ has sufficient bending stiffness, to suppress displacement and deformation between the supporting structural members 102; and the shape of the rectangle may also be replaced with any cross-sectional shape that meets a support requirement and casting process as required.

In another alternative or additional embodiment, both the crankcase 100 and the crosshead case 200 are integrally cast, and the crankcase 100 and the crosshead case 200 are sealingly connected. The sealing connection between the crankcase 100 and the crosshead case 200 refers to sealing space in the crankcase 100 for mounting the crankshaft and a crosshead cavity 211 of the crosshead case 200.

In addition, a first reinforcing rib 103 below a connecting rod through hole 117 on the front end surface 106 blocks lubricating oil drained from an end of a slide rail from flowing into the oil return port. Therefore, a rectangular oil drain through hole 118 is cast on the first reinforcing rib 103. Refer to FIG. 14, the diagram on the right side shows a front end surface 106 of a crankcase 100 as well as connecting rod through holes 117 and oil drain through holes 118, and the diagram on the left side is an enlarged view of the oil drain through hole 118; a shape of the oil drain through hole 118 is not limited, provided that a crosshead slide rail smoothly drains oil without excessively weakening a strength of the first reinforcing rib 103; through hole forming process is not limited. The through holes may be integrally cast, machined, or formed in other manners of removing materials; positions of the through holes are not limited. The through holes may be spaced apart at each section of reinforcing rib 103, or spaced apart on the supporting structural member 102; and a quantity of through holes is not limited. One or more through holes may be provided at each section, but it is ensured that each crosshead corresponds to at least one through hole.

In embodiments of this application, the crankcase 100 is integrally cast. The crankcase 100 manufactured by using the integrally casting process may avoid a plurality of welding defects, for example, defects such as welding deformation, excessive welding stress, and the like, which makes a strength of the power end housing greater, to extend a service life of the power end housing. In addition, the integrally casting process is performed on the crankcase 100, which may reduce manufacturing process difficulty of the power end housing.

In addition, it should be noted that the crankcase 100 may include legs 119 configured to support the crankcase 100, for example, the legs may be a plurality of legs 119. Bottom portions of the plurality of legs 119 are on the same plane, and are fixed on a chassis 500 through anchor bolts, to provide support and fixation for the entire power end, and improve system stability. FIG. 15 shows a state in which a crankcase 100 and a crosshead case 200 are jointly connected to a chassis 500, and shows a plurality of legs 119 of the crankcase.

At least one leg 119 is arranged on a front end surface 106 side and a rear end surface 107 side on each supporting structural member 102. Additional legs 119 may also be arranged between the two legs 119 as required, refer to FIG. 16; or one transverse integrated leg 119′ extending from the front end surface 106 to the rear end surface 107 is arranged at the bottom portion of each supporting structural member 102. FIG. 17 shows a transverse integrated leg 119′ and a longitudinal integrated leg 119″. The front end surface 106 and the rear end surface 107 of the crankcase 100 are configured to connect each supporting structural member 102 and ensure that the entire case body is closed, and are not a part of the supporting structural member 102. The front end surface 106 refers to a surface of a side of the crankcase 100 that is connected to the crosshead case 200; and the rear end surface 107 refers to a surface of an opposite side of the side of the crankcase 100 that is connected to the crosshead case 200.

The positions and the quantity of legs 119 are not limited to that of legs 119 on the supporting structural member 102. For example, longitudinal integrated legs 119″ extending from the supporting structural member 102 on one side to the supporting structural member 102 on an other side may be arranged.

FIG. 18 shows a partially enlarged view of a leg 119, in which a bevel 120 is arranged on a root portion of the leg 119. A main objective is to improve a bending resistance strength of the root portion of the leg 119, and the arrangement of the bevel 120 is conducive to satisfying casting process; a form of the bevel 120 is not limited, and the bevel 120 may be set into a bevel or an arc shape (equal curvature or variable curvature) as required; and a transition fillet of a great size is arranged at a joint with the case body, to further increase the bending resistance strength of the root portion.

In addition, a cross section of the leg 119 is in a shape of a rectangle, and a direction (transverse direction) from the front end surface 106 to the rear end surface 107 is a long axial direction, which makes a moment of inertia of a rectangular cross section greater, and ensures that the leg has sufficient bending stiffness; or the cross section of the leg 119 is in an arbitrary shape, which ensures bending resistance stiffness of the root portion of the leg 119, and provides reliable support.

Weight-reducing grooves 121 are provided on two side surfaces of the leg, shapes of the weight-reducing grooves 121 are not limited, and depths of the weight-reducing grooves 121 are determined according to a requirement of support stiffness; a starting edge and an ending edge of the weight-reducing groove 121 have transition fillets; and the weight-reducing groove 121 is away from a bottom portion contact surface 123, to provide space for anchor threaded holes 124 at the bottom portion of the leg 119, thereby ensuring a strength of threaded connection. Anchor bolts in the anchor threaded holes 124 provide fastening connection with a chassis 500, and incomplete threads at a first end of the threaded holes are removed, to improve stiffness of the threaded connection.

FIG. 19 is a cross-sectional view of a side of a crankcase showing an entire bearing seat hole. A side surface of the crankcase 100 is in a shape of an octagon. A polygonal structure may ensure stiffness of the housing, and the mass is smaller under the same volume, which may effectively reduce a weight of the housing, and provide more mounting surfaces for a process window plate; or a side surface of the crankcase 100 may be in a shape of another housing, such as a constant curvature spherical surface or a variable curvature spherical surface; a top portion 104 and a bottom portion 105 are symmetrically arranged along an axis of the plunger, which may better ensure uniform deformation; and the front end surface 106 is parallel to the rear end surface 107, and a distance between the front end surface 106 and the rear end surface 107 depends on a size of a pump component.

In a case of a polygonal housing, especially an octagonal housing, a processing and mounting plane is provided for a process window. To facilitate mounting of a connecting rod cover and a connecting rod body, four process windows are arranged at positions obliquely upward and downward corresponding to the connecting rod cover on the front end surface 106, the rear end surface 107, and the front end surface 106. It should be noted that the process window on the front end surface 106 may be a connecting rod through hole through which a connecting rod of the crankshaft enters the crosshead case. Therefore, it needs to be ensured that four planes of the four process windows are mounted. In addition, to ensure that the housing of the entire crankcase 100 is symmetrical, evenly supported, and light in weight, eight surfaces are set on the whole crankcase 100, and layout of each reinforcing rib 103, 103′ is avoided, to prevent excessive weakening of the strength of the reinforcing ribs 103, 103′.

Refer to FIG. 7 and FIG. 20, FIG. 7 is a perspective view of a crankcase, in which an oil and gas separator boss 125 is shown; and in addition, FIG. 20 is a cutaway perspective view of a crankcase, in which a partially cutaway view of a plurality of oil and gas separator bosses arranged on a top portion of a crankcase 100 is shown. A plurality of oil and gas separator bosses 125 are arranged on the top portion 104, to facilitate processing of a mounting plane. A transition fillet is arranged between the boss 125 and the top portion 104, to further improve stiffness of a joint. A quantity and positions of bosses 125 are not limited (a top portion or other positions); and because an integrally casting housing has strong airtightness, arranging an oil and gas separator may release internal gas and isolate external impurities, thereby helping to balance the air pressure inside and outside the housing. The oil and gas separator is arranged to balance the air pressure inside and outside the crankcase 100, and prevent external water vapor from intruding into the crankcase 100. Water vapor accelerates corrosion of internal pump parts. As abrasive particles, rust particles accelerate wear of metal parts. In addition, free water flashing on a hot metal surface causes pitting corrosion. A long period of time of intrusion of water vapor causes lubricating oil in the crankcase 100 to emulsify, resulting in a sharp decrease in lubricating performance of the lubricating oil, which in turn affects a surface friction coefficient of lubricating parts, and eventually leading to abnormal wear of bearing bushes, and even tile burning.

Refer to FIG. 21 and FIG. 22, FIG. 21 is a perspective view of a crankcase 100 seen from below, and FIG. 22 is a perspective view of a state in which an oil return port cover plate is not mounted on a crankcase 200. One or more oil return ports 126 (a quantity of oil return ports 126 depends on a quantity and positions of reinforcing ribs 103, 103′ and supporting structural members 102) are evenly spaced apart on the bottom portion 105 between the supporting structural members 102. The oil return ports 126 (namely, away from the supporting structural members 102) are provided at vacant positions between every two supporting structural members 102. The arrangement of the oil return ports 126 facilitates recovery, circulation, and cooling of the lubricating oil. Forming process of the oil return ports 126 is not limited. The oil return ports 126 may be integrally cast, machined, or formed in other manners of adding or removing materials; a shape of the oil return port 126 is not limited to a circle; and an oil return cover plate mounting boss 127 is arranged on an outer ring, to facilitate sealing of an integrated cover plate 128, or split cover plates may be used for separate sealing. For example, the integrated cover plate 128 may be detachably mounted on the oil return cover plate mounting boss 127 to seal the oil return port 126. All the oil return ports 126 do not need to be strictly provided in a straight line as shown in the figure. In this case, the oil return ports 126 are arranged in a straight line for the sake of aesthetic symmetry and regular arrangement of oil return pipes.

FIG. 23 and FIG. 24 separately show each process window 129, 129′ on a crankcase 100 penetrating in a direction from an outer surface of a housing toward a crankshaft. A plurality of circular process windows are arranged on two sides of a top portion 104 and a bottom portion 105 and serve as the process windows 129, to facilitate tightening connecting bolts in a three-section connecting rod, and reduce a weight of the housing; a quantity of process windows 129 is not limited, and a shape of the process window 129 is not limited to a circle, provided that the process window 129 does not block a bolt tightening tool from tightening bolts; and window forming process is not limited. The process windows may be integrally cast, machined, or formed in other manners of removing materials. Components inside the crankcase 100, such as the crankshaft, may be observed and/or operated through the process window.

A plurality of long rectangular process windows are arranged on a rear end surface 107 and serve as the process windows 129′, to facilitate assembly of a connecting rod cover and a connecting rod body, and reduce the weight of the housing; and a quantity of long rectangular process windows depends on a quantity of cylinders of the fracturing pump, and a shape of the process window is not limited to a long rectangle. The process window on the rear end surface 107 allows the connecting rod cover to pass through smoothly during mounting. An opening, referred to as a connecting rod through hole 117, similar to the process window 129′ is provided on the front end surface 106, so that the connecting rod body passes through smoothly during mounting, and an extended end of a crosshead sliding sleeve is allowed to extend in, provided that normal swing of the connecting rod during operation is not hindered. In addition, rectangular recesses 130 are arranged on outer rings of the five process windows 129′ on the rear end surface 107, so that the five process windows 129′ are still flush with the rear end surface 107 after the cover plate is mounted. Mounting bolts of the cover plate are countersunk head bolts, so that there are no protruding parts in an entire cover plate mounting region, preventing scratches and bumps, and also reducing a weight of the crankcase 100 to a certain extent. FIG. 25 shows a state in which a cover plate 122 is mounted on a rear end surface 107. Forming process of the process windows 129 and the recesses 130 is not limited. The process windows 129 and the recesses 130 may be integrally cast, machined, or formed in other manners of removing materials.

Refer to FIG. 26 to FIG. 33, FIG. 26 is a perspective view before a crankcase 100 and a crosshead case 200 are connected by bolts; FIG. 27 is a perspective view from another angle before a crankcase 100 and a crosshead case 200 are connected by bolts; FIG. 28 is a side view of a crankcase 100 showing two threaded holes on a cross section and a partially enlarged view of two threaded holes; FIG. 29 is a cross-sectional view of a crankcase 100 and a crosshead case 200 that are connected together by two bolts; FIG. 30 is a partially enlarged view of connection by two bolt; FIG. 31 is a cross-sectional view of one-to-one arrangement of two bolts; FIG. 32 is a cross-sectional view of one-to-two arrangement of two bolts; and FIG. 33 is a cross-sectional view showing a relationship between arrangement positions of two bolts. It may be learnt that a crosshead case 200 is connected to a crankcase 100 by using two bolts. In a first bolt connection, a plurality of long first bolts 131 are used for overall fixation and pre-tightening. In a second bolt connection, a second bolt 132 on an outer ring of the first bolt 131 is used for sealing and tightening. A sealing groove 133 and a sealing member are provided on a sealing surface on a front end surface 106 of the crankcase 100, or the sealing surface is directly sealed by using a sealant, to avoid oil and gas leakage, and prevent adverse consequences such as contamination of lubricating oil by water vapor, and corrosion and wear of internal metal parts. Compared with being connected and sealed by one bolt, double fixation and connection by two bolts may effectively ensure fit and tightening of the sealing surface, prevent the sealing surface from disengaging and slipping due to a plunger force and a lateral force of a connecting rod, and block leakage of oil, gas, and oil pressure. In other embodiments, arrangement of bolts is not limited to two bolts, and a plurality of bolt connections may be set according to a connection and sealing requirement, and space layout.

Two rows of first threaded holes 141 for long first bolts 131 are provided on the sealing surface at positions corresponding to the supporting structural members 102. Most of the first threaded holes 141 are evenly provided. Specific positions of the first threaded holes 141 are related to an arrangement manner of the supporting structural members 102. In other words, the first threaded holes 141 for the long first bolts 131 are drilled into the supporting structural members 102 from the front end surface 106 of the crankcase 100, and are used for the first bolt connection; and to ensure sufficient stiffness at a threaded joint, a sinking platform with a diameter slightly greater than a diameter of the threaded hole is arranged at an opening of the threaded hole, and a sinking depth is greater than or equal to one thread pitch, to avoid the first few threads being pulled off due to insufficient stiffness during tightening, or the sealing surface being tensile and deformed, which affects a sealing and connection effect.

In this embodiment, diameters of the first threaded holes 141 at two ends are less than the diameter of the middle-section first threaded hole 141. This is because the long first bolt 131 in the middle section needs to simultaneously bear superposition of axial tensile forces of the connecting rod and the crosshead on left and right sides, and the diameter needs to be increased to ensure a tensile strength of the bolt. The first bolt 131 with two long ends is subject to a relatively small unilateral axial force, and the diameter of the bolt may be appropriately reduced. The diameters of the first threaded holes may also be set the same according to usage requirements, and a quantity and depths of threaded holes are not limited. It should be noted that the first threaded holes 141 at two ends are the first threaded holes 141 located at two ends of the crankcase 100 in a length direction X, and the middle-section first threaded hole 141 is located between the first threaded holes 141 at two ends.

In addition, an upper row and a lower row of second threaded holes 142 configured to connect the crosshead case 200 are provided on the sealing surface, or the second threaded holes 142 are provided along an outer edge of the crosshead case 200, and are used for the second bolt connection; and distances between the second threaded holes 142 may be the same or different (evenly provided or unevenly provided). As mentioned above, the first threaded holes 141 are provided in two rows at upper end and a lower end of each supporting structural member 102, and the second threaded holes 142 are provided at specific intervals on the front end surface 106 along the outer rings of the first threaded holes 141. The first threaded holes 141 may be provided in one-to-one correspondence or one-to-many correspondence with the second threaded holes 142. For example, the second threaded holes 142 may be densely provided around the first threaded holes 141, to form a greater threaded clamping region that does not affect each other, and ensure that a contact surface between the two bolts is not loosened.

For a detailed description of a relationship between a shape and an area of a triangular region formed by the two threaded holes and a sealing strength effect, refer to the following description.

When the bolt is screwed into the threaded hole and is tightened, connected parts are deformed under pressure and have a tendency to rebound. A contact surface between the crankcase 100 and the crosshead case 200 forms a circular clamping region (a diameter is approximately 1.5 to 2 times a nominal diameter of the threaded hole) centered on an axis of the threaded hole. Proper arrangement of triangular threaded holes that are provided in one-to-two correspondence, namely, one first threaded hole 141 being provided corresponding to two second threaded holes 142, combines to form a greater clamping region, thereby further improving a clamping effect of two contact surfaces. For example, the triangle may be an equilateral triangle. When a distance between the three vertices is too far, excessive separation of the clamping region of each bolt affects a tightening effect, and loosening and leakage may occur under the impact of reciprocating movement of the plunger for a long period of time; and conversely, if the distance between the three vertices is too close, each circular clamping region overlaps with each other, which is not only detrimental to expansion of the sealing clamping region, but also causes superposition of compressing forces in some regions, leading to damage to surfaces of the connected parts.

An incomplete thread at the first end of each threaded hole is removed, to improve the stiffness of the threaded connection; and a connection manner between the crankcase 100 and the crosshead case 200 is not limited to the threaded connection, and any connection manner that ensures a tight connection between the crankcase 100 and the crosshead case 200 without relative displacement may be used. For example, an external clamping structure is used to clamp and position two contact surfaces, or manners such as an electromagnetic suction connection manner, a hydraulic connection manner, an automatic connection hook, and the like are used. However, considering that the foregoing solutions each require an external clamping mechanism, a structure is complex, manufacturing and maintenance costs are high, and the sealing surface may loosen under the reciprocating action of an extremely great plunger force. Considering the manufacturing cost and connection reliability, the threaded connection is selected in this example.

A sealing groove 133 is provided on a connecting end surface between the crankcase 100 and the crosshead case 200, refer to FIG. 34. The sealing groove 133 is provided around an outer ring of a long first threaded hole 141 and a connecting rod through hole 117, and bypasses outer rings of an exhaust cavity and a slide rail cavity of the crosshead case 200. In this case, the connecting rod through hole 117 through which the connecting rod of the crankshaft passes through and enters the crosshead case 200 is located on an inner side of the sealing groove 133, thereby facilitating effective sealing of the connecting rod through hole. A function of the sealing groove 133 is to place a sealing ring, and clamping of the bolts causes a contact compression stress to be generated between a contact surface between the two sealing parts, namely, the crankcase and the crosshead case, and the sealing ring. Under the action of the pressure, the sealing ring elastically deforms to fill and seal a gap between the two contact surfaces, thereby achieving an objective of sealing oil and gas inside the housing. As shown in the figure, two bolts 131 and 132 are arranged outside the sealing groove 133. The sealing groove 133 is provided around the first threaded hole 141 and the second threaded hole 142 and a shape of the crosshead slide rail and a shape of the crosshead exhaust cavity in a winding manner. The two threaded holes 141 and 142 are provided outside the sealing groove 133 and the winding design may separate a circumferential surface of the long bolt from the contact sealing surface, so that the entire long threaded hole may communicate with the air pressure. In addition, a sealing length is also increased to a certain extent, and the sealing reliability is improved. In addition, a forming manner of the sealing groove is not limited, and other manners of removing materials other than machining may be used; sealing parts are placed in the groove, including but not limited to a sealing ring, a sealing ring, and the like; or the sealing groove is canceled, and a sealant is directly used to perform sealing.

The front end surface 106 of the crankcase 100 has a lubricating oil hole leading to the bearing seat 101, and a forming manner is not limited; additional branches are spaced apart on a built-in lubricating oil passage of the crosshead case 200 to be connected to the oil holes on the front end surface 106 of the crankcase 100. The oil passage leads to the oil holes that are on each support surface of the bearing and that are configured to lubricate the bearing. Positions of the oil holes need to be aligned with grooves of the oil holes on an outer ring of the bearing; and if difficulty of processing the oil passage is ignored, a quantity, angles, and positions of branches may not be limited, provided that an objective of lubricating the bearing is achieved. A region affected by force bearing of the threaded hole needs to be avoided, to avoid weakening a strength of the threaded connection, or deforming and blocking the oil holes caused by screwing in the bolt.

To prevent the lubricating oil from leaking, end surfaces of the oil holes connected to the crosshead case 200 and the crankcase 100 require a separate sealing groove and a sealing part (including but not limited to a sealing ring and a sealing ring), or separate coating of a sealant, and the like, and a sealing manner is not limited.

The double bolt connection manner is not limited to the connection between the split cast crankcase 100 and the crosshead case 200. Similarly, a connection between the split tailor-welded crankcase 100 and the crosshead case 200 is also applicable, or any combination of connections is also applicable, such as a connection between the tailor-welded crankcase 100 and the cast crosshead case 200, a connection between the cast crankcase 100 and the tailor-welded crosshead case 200, and the like.

In addition, this application further provides a plunger pump including the power end housing. The plunger pump may further include a hydraulic end housing. The hydraulic end housing, the crosshead case 200, and the crankcase 100 may be sequentially connected together. A first threaded hole 141 may penetrate from the hydraulic end housing to the crankcase 100, and a first bolt 131 may connect the hydraulic end housing, the crosshead case 200, and the crankcase 100 together through the first threaded hole 141.

Specifically, the present technology may have the following configuration.

• • (A1) A power end housing for a plunger pump, including:

an integrated crankcase 100, where the crankcase 100 includes a plurality of bearing seats 101 and a plurality of supporting structural members 102, the supporting structural members 102 are configured to support the bearing seats 101, the supporting structural members 102 are spaced apart in an axial direction of the bearing seats 101, and the crankcase 100 includes a first reinforcing rib 103 between every two supporting structural members 102, where an angle between a direction of a maximum resultant force on the bearing seats 101 and an axial direction of a plunger of the plunger pump is βmax, an angle between the first reinforcing rib 103 and the axial direction of the plunger is a first angle, and the first angle is greater than or equal to 0.8 βmax and less than or equal to 1.2 βmax.

• • (A2) The power end housing according to (A1), where the first reinforcing rib 103 is arranged at least on a front end surface 106 and/or a rear end surface 107 of the crankcase 100, the front end surface 106 is a surface of a side of the crankcase 100 that is connected to a crosshead case 200, and the rear end surface 107 is a surface of an opposite side of the front end surface 106.
  • (A3) The power end housing according to (A2), where a group of first reinforcing ribs 103 are separately arranged on the front end surface 106 and the rear end surface 107, and the first reinforcing ribs 103 in each group are symmetrical to each other relative to the axial direction of the plunger of the plunger pump.
  • (A4) The power end housing according to (A3), where the group of first reinforcing ribs 103 arranged on the front end surface 106 and the group of first reinforcing ribs 103 arranged on the rear end surface 107 are symmetrical to each other relative to a vertical centerline of the bearing seats 101.
  • (A5) The power end housing according to (A3), where each group of first reinforcing ribs 103 includes two first reinforcing ribs 103, and an angle between extending directions of the two first reinforcing ribs 103 is greater than or equal to 1.8 βmax and less than or equal to 2.2 βmax.
  • (A6) The power end housing according to (A1), where the crankcase 100 further includes a plurality of second reinforcing ribs 103′ between every two supporting structural members 102, and extending directions of the second reinforcing ribs 103′ pass through a center of a circle of the bearing seat 101.
  • (A7) The power end housing according to (A6), where the plurality of second reinforcing ribs 103′ are symmetrically arranged along seat holes of the bearing seat 101.
  • (A8) The power end housing according to (A6), where the plurality of second reinforcing ribs 103′ are arranged on an upper side and a lower side of the bearing seat 101, where three upper side reinforcing ribs 103′ are arranged on the upper side and two lower side reinforcing ribs 103′ are arranged on the lower side, and the two lower side reinforcing ribs 103′ are separately located on two sides of a bottom portion oil return port without interfering with the bottom portion oil return port.
  • (A9) The power end housing according to any one of (A1) to (A8), where a transition bevel 115 is arranged between the first reinforcing rib 103 and/or the second reinforcing rib 103′ and the supporting structural member 102, and there is a transition fillet 116 between the bevel 115 and the supporting structural member 102.
  • (A10) The power end housing according to any one of (A1) to (A8), where a cross section of the first reinforcing rib 103 and/or the second reinforcing rib 103′ is in a shape of a rectangle.
  • (A11) The power end housing according to (A2), where a through hole 118 is provided on the first reinforcing rib 103 below a connecting rod through hole 117 on the front end surface 106 of the crankcase 100.
  • (A12) The power end housing according to (A1), where a width of the bearing seat 101 is defined by a width of a bearing imposed on the bearing seat 101, the bearing seat 101 includes two end portion bearing seats 101 located at two ends of the crankcase 100 and several middle-section bearing seats 101, and the middle-section bearing seats 101 are located between the two end portion bearing seats 101, where a width of each middle-section bearing seat 101 is greater than a width of each of the two end portion bearing seats 101.
  • (A13) The power end housing according to (A12), where a width of one of the two end portion bearing seats 101 located on a reduction case connection side of the crankcase 100 is greater than a width of an other of the two end portion bearing seats 101.
  • (A14) The power end housing according to (A1), where spacings between the supporting structural members 102 are different, and relative to a center of a length direction X of the crankcase 100, the spacings between the supporting structural members 102 are set to be symmetrical to each other, and where length direction X is parallel to the axial direction of the bearing seat 101.
  • (A15) The power end housing according to (A1), where weight-reducing grooves 109 are provided on the supporting structural member 102.
  • (A16) The power end housing according to (A15), where a starting edge and an ending edge of the weight-reducing groove 109 have transition fillets.
  • (A17) The power end housing according to (A1), where hoisting point bosses 110 are arranged on a top portion of the supporting structural member 102, and a transition fillet is arranged at a joint between the hoisting point boss 110 and a case body of the crankcase 100.
  • (A18) The power end housing according to (A1), where a bottom portion of the crankcase 100 includes legs 119, and the legs 119 are configured to support the crankcase 100.
  • (A19) The power end housing according to (A18), where each supporting structural member 102 includes at least one leg 119 on both a front end side and a rear end side of the crankcase 100, the front end side is a side of the crankcase 100 connected to a crosshead case 200, and the rear end side is an opposite side of the front end side.
  • (A20) The power end housing according to (A18), where the legs 119 are transverse integrated legs 119′ arranged at a bottom portion of each supporting structural member 102 and extending from a front end side to a rear end side of the crankcase 100, the front end side is a side of the crankcase 100 that is connected to a crosshead case 200, and the rear end side is an opposite side of the front end side.
  • (A21) The power end housing according to (A18), where the legs 119 are longitudinal integrated legs 119″ extending from the supporting structural member 102 at one end to the supporting structural member 102 at the other end in a length direction X of the crankcase 100, and the length direction X is parallel to an axial direction of the bearing seat 101.
  • (A22) The power end housing according to any one of (A18) to (A21), where bevels 120 are arranged on root portions of the legs 119, 119′, 119″, and a transition fillet is arranged at a joint between the bevel 120 and the crankcase 100.
  • (A23) The power end housing according to any one of (A18) to (A21), where weight-reducing grooves 121 are provided on the legs 119, 119′, 119″, the weight-reducing grooves 121 are away from bottom portion contact surfaces 123 of the legs 119, 119′, 119″, and a starting edge and an ending edge of the weight-reducing groove 121 have transition fillets.
  • (A24) The power end housing according to (A1), where at least one oil and gas separator boss 125 is arranged on a top portion 104 of the crankcase 100.
  • (A25) The power end housing according to (A1), where at least one oil return port 126 is provided at a bottom portion 105 of the crankcase 100.
  • (A26) The power end housing according to (A25), where the power end housing further includes an integrated cover plate 128, an oil return cover plate mounting boss 127 is arranged on an outer ring of the oil return port 126, and the integrated cover plate 128 may be detachably mounted on the oil return cover plate mounting boss 127 to seal the oil return port 126.
  • (A27) The power end housing according to (A1), where process windows 129, 129′ that penetrate from an outer surface of the housing toward a direction of a crankshaft are arranged on the crankcase 100, and through the process windows 129, 129′, components inside the crankcase 100 are observed and/or operated.
  • (A28) The power end housing according to (A1), where a plurality of first threaded holes 141 are provided on a surface of a side of the crankcase 100 close to a crosshead case 200, and the first threaded holes 141 are configured to connect the crankcase 100 and the crosshead case 200 through first bolts 131.
  • (A29) The power end housing according to (A1), where a sealing surface is arranged on a surface of a side of the crankcase 100 close to a crosshead case 200, a sealing groove 133 is provided on the sealing surface, and a connecting rod through hole of the crankcase 100 is located on an inner side of the sealing groove 133.
  • (A30) The power end housing according to (A1), where lubricating oil holes leading to the bearing seat 101 are provided on a surface of a side of the crankcase 100 close to a crosshead case 200, and positions of the lubricating oil holes are aligned with grooves of oil holes on an outer ring of a bearing.
  • (A31) The power end housing according to (A1), where the crankcase 100 is integrally cast.
  • (A32) A plunger pump, where the plunger pump includes the power end housing according to any one of (A1) to (A31).
  • (A33) The plunger pump according to (A32), further including a hydraulic end housing, where the power end housing further includes a crosshead case 200, and the hydraulic end housing, the crosshead case 200, and the crankcase 100 are sequentially connected, where first threaded holes 141 penetrate from the hydraulic end housing to the crankcase 100, and first bolts 131 connect the hydraulic end housing, the crosshead case 200, and the crankcase 100 together through the first threaded holes 141.
  • (A34) The plunger pump according to (A33), second threaded holes 142 are further provided on a surface of a side of the crankcase 100 close to the crosshead case 200, the second threaded holes 142 at least penetrate from the crosshead case 200 to the crankcase 100, and a second bolt 132 at least sealingly connects the crosshead case 200 and the crankcase 100 through the second threaded holes 142.
  • (A35) The plunger pump according to (A34), the second threaded holes 142 are provided along outer rings of the first threaded holes 141 and are at specific intervals with the first threaded holes 141.
  • (A36) The power end housing according to (A35), where the first threaded holes 141 are provided in one-to-two correspondence with the second threaded holes 142, and position connection lines between one first threaded hole 141 and two second threaded holes 142 corresponding to each other form a triangle.
  • (B1) A power end housing for a plunger pump, including:

an integrated crankcase 100, where the crankcase 100 includes a plurality of bearing seats 101 and a plurality of supporting structural members 102, the supporting structural members 102 are configured to support the bearing seats 101, and the supporting structural members 102 are spaced apart in an axial direction of the bearing seats 101, where a width of the bearing seat 101 is defined by a width of a bearing imposed on the bearing seat 101.

• • (B2) The power end housing according to (B1), where the bearing seat 101 includes two end portion bearing seats 101 located at two ends of the crankcase 100 and several middle-section bearing seats 101, and the middle-section bearing seats 101 are located between the two end portion bearing seats 101, where a width of each middle-section bearing seat 101 is greater than a width of each of the two end portion bearing seats 101.
  • (B3) The power end housing according to (B2), where a width of one of the two end portion bearing seats 101 located on a reduction case connection side of the crankcase 100 is greater than a width of an other of the two end portion bearing seats 101.
  • (B4) The power end housing according to (B1), where spacings between the supporting structural members 102 are different, and relative to a center of a length direction X of the crankcase 100, the spacings between the supporting structural members 102 are set to be symmetrical to each other, and where length direction X is parallel to the axial direction of the bearing seat 101.
  • (B5) The power end housing according to (B1), where weight-reducing grooves 109 are provided on the supporting structural member 102.
  • (B6) The power end housing according to (B5), where a starting edge and an ending edge of the weight-reducing groove 109 have transition fillets.
  • (B7) The power end housing according to (B1), where hoisting point bosses 110 are arranged on a top portion of the supporting structural member 102, and a transition fillet is arranged at a joint between the hoisting point boss 110 and a case body of the crankcase 100.
  • (B8) The power end housing according to (B1), where a bottom portion of the crankcase 100 includes legs 119, and the legs 119 are configured to support the crankcase 100.
  • (B9) The power end housing according to (B8), where each supporting structural member 102 includes at least one leg 119 on both a front end side and a rear end side of the crankcase 100, the front end side is a side of the crankcase 100 connected to a crosshead case 200, and the rear end side is an opposite side of the front end side.
  • (B10) The power end housing according to (B8), where the legs 119 are transverse integrated legs 119′ arranged at a bottom portion of each supporting structural member 102 and extending from a front end side to a rear end side of the crankcase 100, the front end side is a side of the crankcase 100 that is connected to a crosshead case 200, and the rear end side is an opposite side of the front end side.
  • (B11) The power end housing according to (B8), where the legs 119 are longitudinal integrated legs 119″ extending from the supporting structural member 102 at one end to the supporting structural member 102 at the other end in a length direction X of the crankcase 100, and the length direction X is parallel to an axial direction of the bearing seat 101.
  • (B12) The power end housing according to any one of (B8) to (B11), where bevels 120 are arranged on root portions of the legs 119, 119′, 119″, and a transition fillet is arranged at a joint between the bevel 120 and the crankcase 100.
  • (B13) The power end housing according to any one of (B8) to (B11), where weight-reducing grooves 121 are provided on the legs 119, 119′, 119″, the weight-reducing grooves 121 are away from bottom portion contact surfaces 123 of the legs 119, 119′, 119″, and a starting edge and an ending edge of the weight-reducing groove 121 have transition fillets.
  • (B14) The power end housing according to (B1), where at least one oil and gas separator boss 125 is arranged on a top portion 104 of the crankcase 100.
  • (B15) The power end housing according to (B1), where at least one oil return port 126 is provided at a bottom portion 105 of the crankcase 100.
  • (B16) The power end housing according to (B15), where the power end housing further includes an integrated cover plate 128, an oil return cover plate mounting boss 127 is arranged on an outer ring of the oil return port 126, and the integrated cover plate 128 may be detachably mounted on the oil return cover plate mounting boss 127 to seal the oil return port 126.
  • (B17) The power end housing according to (B1), where process windows 129, 129′ that penetrate from an outer surface of the housing toward a direction of a crankshaft are arranged on the crankcase 100, and through the process windows 129, 129′, components inside the crankcase 100 are observed and/or operated.
  • (B18) The power end housing according to (B1), where a plurality of first threaded holes 141 are provided on a surface of a side of the crankcase 100 close to a crosshead case 200, and the first threaded holes 141 are configured to connect the crankcase 100 and the crosshead case 200 through first bolts 131.
  • (B19) The power end housing according to (B1), where a sealing surface is arranged on a surface of a side of the crankcase 100 close to a crosshead case 200, a sealing groove 133 is provided on the sealing surface, and a connecting rod through hole of the crankcase 100 is located on an inner side of the sealing groove 133.
  • (B20) The power end housing according to (B1), where lubricating oil holes leading to the bearing seat 101 are provided on a surface of a side of the crankcase 100 close to a crosshead case 200, and positions of the lubricating oil holes are aligned with grooves of oil holes on an outer ring of a bearing.
  • (B21) The power end housing according to (B1), where the crankcase 100 is integrally cast.
  • (B22) The power end housing according to (B1), where the crankcase 100 includes a plurality of second reinforcing ribs 103′ between every two supporting structural members 102, and extending directions of the second reinforcing ribs 103′ pass through a center of a circle of the bearing seat 101.
  • (B23) The power end housing according to (B22), where the plurality of second reinforcing ribs 103′ are symmetrically arranged along seat holes of the bearing seat 101.
  • (B24) The power end housing according to (B22), where the plurality of second reinforcing ribs 103′ are arranged on an upper side and a lower side of the bearing seat 101, where three upper side reinforcing ribs 103′ are arranged on the upper side and two lower side reinforcing ribs 103′ are arranged on the lower side, and the two lower side reinforcing ribs 103′ are separately located on two sides of a bottom portion oil return port without interfering with the bottom portion oil return port.
  • (B25) The power end housing according to (B22), where a transition bevel 115 is arranged between the second reinforcing rib 103′ and the supporting structural member 102, and there is a transition fillet 116 between the bevel 115 and the supporting structural member 102.
  • (B26) The power end housing according to (B22), where a cross section of the second reinforcing rib 103′ is in a shape of a rectangle.
  • (B27) A plunger pump, where the plunger pump includes the power end housing according to any one of (B1) to (B26).
  • (B28) The plunger pump according to (B27), further including a hydraulic end housing, where the power end housing further includes a crosshead case 200, and the hydraulic end housing, the crosshead case 200, and the crankcase 100 are sequentially connected, where first threaded holes 141 penetrate from the hydraulic end housing to the crankcase 100, and first bolts 131 connect the hydraulic end housing, the crosshead case 200, and the crankcase 100 together through the first threaded holes 141.
  • (B29) The plunger pump according to (B28), second threaded holes 142 are further provided on a surface of a side of the crankcase 100 close to the crosshead case 200, the second threaded holes 142 at least penetrate from the crosshead case 200 to the crankcase 100, and a second bolt 132 at least sealingly connects the crosshead case 200 and the crankcase 100 through the second threaded holes 142.
  • (B30) The plunger pump according to (B29), the second threaded holes 142 are provided along outer rings of the first threaded holes 141 and are at specific intervals with the first threaded holes 141.
  • (B31) The power end housing according to (B30), where the first threaded holes 141 are provided in one-to-two correspondence with the second threaded holes 142, and position connection lines between one first threaded hole 141 and two second threaded holes 142 corresponding to each other form a triangle.

The foregoing descriptions merely illustrates example embodiments of the present disclosure and are not intended to limit the present disclosure. For a person having ordinary skill in the art, various modifications and variations can be made to the present disclosure. Any modification, equivalent replacement, or improvement made within the spirit and principles of the present disclosure shall fall within the protection scope of the present disclosure.

Claims

1. A power end housing for a plunger pump, comprising an integrated crankcase (100), wherein: the integrated crankcase (100) comprises a plurality of bearing seats (101) and a plurality of supporting structural members (102);the plurality of supporting structural members (102) are configured to support the plurality bearing seats (101);the plurality of supporting structural members (102) are spaced apart in an axial direction of the plurality of bearing seats (101);the integrated crankcase (100) comprises first reinforcing ribs (103) between every two adjacent supporting structural members (102); anda first angle is formed between the first reinforcing ribs (103) and an axial direction of plungers of the plunger pump, the first angle beings greater than or equal to 0.8 βmax and less than or equal to 1.2 βmax, βmax being an angle formed between a direction of a maximum resultant force on the plurality of bearing seats (101) and the axial direction of the plungers.

2. The power end housing according to claim 1, wherein the first reinforcing ribs (103) are arranged at least on a front end surface (106) and/or a rear end surface (107) of the integrated crankcase (100), the front end surface (106) being a surface of a side of the integrated crankcase (100) that is connected to a crosshead case (200), and the rear end surface (107) being a surface at an opposite side of the front end surface (106).

3. The power end housing according to claim 2, wherein respective groups of first reinforcing ribs (103) are separately arranged on the front end surface (106) and the rear end surface (107), and the first reinforcing ribs (103) in each group are symmetrical to each other relative to the axial direction of the plungers of the plunger pump.

4. The power end housing according to claim 3, wherein the group of the first reinforcing ribs (103) arranged on the front end surface (106) and the group of the first reinforcing ribs (103) arranged on the rear end surface (107) are symmetrical to each other relative to vertical centerlines of the plurality of bearing seats (101).

5. The power end housing according to claim 3, wherein each group of the first reinforcing ribs (103) comprise two first reinforcing ribs (103) for each pair of adjacent supporting structural members, and an angle between extending directions of the two first reinforcing ribs (103) is greater than or equal to 1.8 βmax and less than or equal to 2.2 βmax.

6. The power end housing according to claim 1, wherein the integrated crankcase (100) further comprises a plurality of second reinforcing ribs (103′) between every two supporting structural members (102), and radial extending directions of the plurality of second reinforcing ribs (103′) pass through a center axis of the plurality of bearing seats (101).

7. The power end housing according to claim 6, wherein the plurality of second reinforcing ribs (103′) are symmetrically arranged along seat holes of the plurality of bearing seats (101).

8. The power end housing according to claim 6, wherein: the plurality of second reinforcing ribs (103′) are arranged on an upper side and a lower side of the plurality of bearing seats (101);three upper side reinforcing ribs (103′) are arranged on the upper side and two lower side reinforcing ribs (103′) are arranged on the lower side for each of the plurality of bearing seats; andthe two lower side reinforcing ribs (103′) for each of the plurality of bearing seats are separately located on two sides of a bottom portion oil return port without interfering with the bottom portion oil return port.

9. The power end housing according to claims 6, wherein: a transition bevel (115) is arranged between each of the first reinforcing ribs (103) and/or each of the plurality of second reinforcing ribs (103′) and its corresponding supporting structural member (102); anda transition fillet (116) is disposed between the bevel (115) and the corresponding supporting structural member (102).

10. A power end housing for a plunger pump, comprising an integrated crankcase (100), wherein: the integrated crankcase (100) comprises a plurality of bearing seats (101) and a plurality of supporting structural members (102);the plurality of supporting structural members (102) are configured to support the plurality of bearing seats (101);the plurality of supporting structural members (102) are spaced apart in an axial direction of the bearing seats (101); anda width of each of the plurality of bearing seats (101) is defined by a width of a corresponding bearing imposed on the each of the plurality of bearing seats (101).

11. The power end housing according to claim 10, wherein: the plurality of bearing seats (101) comprise two end portion bearing seats (101) located at two ends of the integrated crankcase (100) and one or more middle-section bearing seats (101);the one or more middle-section bearing seats (101) are located between the two end portion bearing seats (101); andthe width of each of the one or more middle-section bearing seats (101) is greater than the width of each of the two end portion bearing seats (101).

12. The power end housing according to claim 11, wherein the width of one of the two end portion bearing seats (101) located on a reduction case connection side of the integrated crankcase (100) is greater than the width of an other of the two end portion bearing seats (101).

13. The power end housing according to claim 11, wherein: spacings between pairs of adjacent supporting structural members of the plurality of supporting structural members (102) are different; andrelative to a center of a length direction (X) of the integrated crankcase (100), the spacings between the pairs of adjacent supporting structural members of the plurality of supporting structural members (102) are set to be symmetrical to each other, the length direction (X) being parallel to the axial direction of the bearing seat (101).

14. The power end housing according to claim 1, wherein each of the plurality of supporting structural member (102) comprises weight-reducing grooves (109).

15. The power end housing according to claim 1, wherein: hoisting point bosses (110) are arranged on a top portion of the plurality of supporting structural members (102); anda transition fillet is arranged at a joint between each of the hoisting point bosses (110) and a case body of the integrated crankcase (100).

16. The power end housing according to claim 1, wherein a bottom portion of the integrated crankcase (100) comprises legs (119), and the legs (119) are configured to support the integrated crankcase (100).

17. The power end housing according to claim 1, wherein: a surface of a side of the integrated crankcase (100) close to a crosshead case (200) comprises a plurality of first threaded holes (141); andthe plurality of first threaded holes (141) are configured to connect the integrated crankcase (100) and the crosshead case (200) through first bolts (131).

18. The power end housing according to claim 1, wherein the integrated crankcase (100) is integrally cast.

19. A plunger pump, wherein the plunger pump comprises the power end housing according to claim 1.

20. The plunger pump according to claim 19, further comprising a hydraulic end housing, wherein: the power end housing further comprises a crosshead case (200);the hydraulic end housing, the crosshead case (200), and the integrated crankcase (100) are sequentially connected;first threaded holes (141) penetrate from the hydraulic end housing to the integrated crankcase (100); andfirst bolts (131) connect the hydraulic end housing, the crosshead case (200), and the integrated crankcase (100) together through the first threaded holes (141).