This patent disclosure relates generally to pump assemblies and, more particularly, to floating cup pump assemblies utilizing a plurality of piston elements disposed around a first rotating surface and a plurality of complimentary cup elements disposed around a second rotating surface. The piston elements reciprocate within the cup elements during rotation.
Pumping devices utilizing a plurality of pistons mounted around a first rotor and a plurality of complimentary cup elements mounted around a swash plate in angled relation to the piston rotor are generally known. One such device is disclosed in United States Patent Application No. 2006/0222516 in the name of Achten having a publication date of Oct. 5, 2006. Embodiments of pumps described in this reference include a rotor having a plurality of pistons projecting away from both sides of the rotor. These embodiments further include a pair of cooperating drum plates supporting an arrangement of cup elements or drum sleeves adapted to house distal portions of the pistons. The rotor supporting the pistons rotates around a first axis of rotation. The drum plates rotate in angled relation to the first axis. The rotor supporting the pistons is rotated in tandem with the drum plates during operation. Due to the angle between the rotor and the drum plates, the pistons are caused to stroke along the length of the corresponding cup elements such that the volume occupied by the piston elements is alternately increased and decreased during a rotational cycle. Thus, fluid introduced into a cup element when the complimentary piston is in a substantially withdrawn position may be pressurized and expelled as the piston is pushed inwardly during the rotational cycle.
The noted reference discloses that the drum plate housing cup elements rotate around a convex centering surface or ball guide that is understood to be integral with a drive shaft. The disclosed pump assembly further incorporates a relatively complex arrangement to control the position of the drum plate relative to an outboard faceplate. Specifically, a plurality of springs is held in a compressed state between a pair of ring structures. One of the ring structures is supported against the curved support surface at a position inboard of the cup springs while the other ring structure is supported against the drum plate at a position outboard of the cup springs. Because the curved support is held in a fixed position integral with the drive shaft, the biasing force of the compressed cup springs is translated across the outboard ring structure to the drum plate thereby urging the drum plate to an outboard position in contact with the faceplate. This arrangement is relatively complex and may be difficult to construct due to the need to hold the cup springs in compressed relation between the ring structures during the assembly process. Accordingly, an alternative construction which provides the desired biasing forces while reducing complexity is desirable.
The foregoing background discussion is intended solely to aid the reader. It is not intended to limit the disclosure, and thus should not be taken to indicate that any particular element of a prior system is unsuitable for use within the disclosed examples, nor is it intended to indicate any element, including solving the motivating problem, to be essential in implementing the examples described herein. The full scope of the implementations and application of the examples described herein are defined by the appended claims.
The disclosure describes, in one aspect, a pump assembly having a rotor supporting a plurality of outwardly projecting piston elements. The rotor is adapted to rotate about a first axis. The pump assembly further includes at least one drum plate supporting a plurality of outwardly projecting cup elements. The drum plate is adapted to rotate about a second axis in angled relation to the first axis. Cup elements supported at the drum plate are adapted to mateably engage distal portions of corresponding piston elements such that the cup elements circumferentially surround such distal portions of the piston elements. The pump assembly further includes a curved surface support element operatively engaging the drum plate. The curved surface support element is mounted in sliding relation along a rotatable shaft structure. At least one biasing element is disposed between the rotor and the curved surface support element thereby urging the curved surface support element and drum plate away from the rotor.
In another aspect this disclosure describes a method for constructing a pump assembly. This method includes providing a rotor supporting a plurality of outwardly projecting piston elements and further providing at least one drum plate supporting a plurality of outwardly projecting cup elements. The rotor and drum plate are oriented in angled relation such that the rotor is rotatable around a first axis and the drum plate is rotatable around a second axis in angled relation to the first axis. A curved surface support element is provided to operatively engage the drum plate. The curved surface support element is mounted in sliding relation along a rotatable shaft structure at least one biasing element is provided between the rotor and the curved surface port element such that the curved surface support element and the drum plate are urged away from the rotor.
This disclosure relates to a pump assembly incorporating a rotor supporting a plurality of outwardly projecting piston elements and at least one complimentary drum plate supporting a plurality of cup elements adapted to engage portions of corresponding piston elements. The rotor and drum plate are angled relative to one another. During a rotational cycle the pistons move in a reciprocating manner relative to the cup elements. A pressure biased support element is disposed in separable relation to a rotatable shaft structure to translate rotational and biasing forces to the drum plate thereby urging the drum plate away from the rotor.
Reference will now be made to the drawings, wherein like reference numerals designate like elements in the various views.
In the exemplary construction illustrated in
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According to the exemplary construction illustrated in
By way of example only, and not limitation, it is contemplated that curved surface support elements 40 may have a substantially unitary construction such that detents 44 are formed integrally with convex exterior support surface 42. Such structures may be formed by casting, powder metallurgy, or other suitable formation techniques using metal alloys or other materials adapted to withstand substantial cyclical stresses. However, it is likewise contemplated that portions of the curved surface support element 40 may be formed separately and thereafter joined together if desired. According to a contemplate practice, the curved surface support elements 40 may be formed separately from components of rotatable shaft structure 12 such that curved surface support elements 40 are non-integral with rotatable shaft structure 12. Curved surface support elements 40 may thereafter be held in separable relationship relative to rotatable shaft structure 12 during operation. That is, curved surface support elements 40 may be subject to nondestructive removal from rotatable shaft structure 12 upon disassembly of pump assembly 10.
As illustrated, an arrangement of detents 44 may extend away from curved surface support elements 40 for keyed engagement with cooperating slot openings 46 in drum plates 18. As rotatable shaft structure 12 is rotated, the rotational movement is translated to drum plates 18 through curved surface support elements 40. As may be seen through comparison of the upper and lower halves of
In the exemplary construction curved surface support elements 40 are continuously biased away from rotor 14 by use of an arrangement of biasing elements 60 such as compression springs or the like disposed at positions around rotatable shaft structure 12. In this regard, it will be understood that biasing elements 60 may be of different constructions on each side of rotor 14 as required to conform to the body contours of rotor 14. In operation, biasing elements 60 apply a compression force which operates along a line of force substantially parallel to the axis of rotation of rotatable shaft structure 12. The biasing elements 60 thus assist in maintaining proper spacing between rotor 14 and curved surface support elements 40 while simultaneously urging curved surface support elements 40 away from rotor 14. As shown, biasing elements may operate directly against rotor 14 and curved surface support elements 40 without the need for intermediate ring structures, although such intermediate ring structures may be used if desired.
Force provided by biasing elements 60 is also utilized to maintain pressure between outer wall portions of drum plates 18 and inner wall portions of face plates 34. As will be appreciated, maintaining such pressure may be beneficial in avoiding leakage between those plate structures. In the illustrated construction, drum plates 18 include an angled cheek portion 70 adapted to engage a segment of convex exterior support surface 42. As shown, angled cheek portion 70 is disposed at an outboard position relative to detents 44 substantially along the line of force provided by biasing element 60. In this regard, it is contemplated that the cheek portions 70 may be integral to drum plates 18 or may be formed as separate components. As curved surface support element 40 is urged away from rotor 14, pressure is applied against cheek portion 70. Thus, a portion of the compressive force provided by biasing element 60 is translated across curved surface support element 40 to drum plate 18. Accordingly, both the curved surface support element 40 and drum plate 18 are continuously urged away from rotor 14 and drum plate 18 is pressed against face plate 34. The continuous pressure of drum plate 18 against face plate 34 aids in maintaining a contacting sealing relation between drum plate 18 and face plate 34. Fluid is thereby prevented from leaking between drum plate 18 and face plate 34.
Although pump assembly 10 may be adapted for any number of uses, according to one contemplated practice, a fluid may be introduced through inlet port 30 which is aligned with openings in drum plate 18 at a position where piston elements 16 are in the maximum withdrawn state relative to corresponding cup elements 20. In this orientation, variable volume chamber 24 has its maximum capacity. As rotatable shaft structure 12 rotates, such rotational movement is translated to rotor 14 and drum plates 18. As noted previously, drum plates 18 are held in non-perpendicular angled relation relative to the axis of rotation for rotatable shaft structure 12 and rotor 14. Thus, as rotor 14 and drum plates 18 rotate, piston elements 16 are caused to move in a substantially reciprocating manner within corresponding cup elements 20. As piston elements 16 move further into cup element 20, pressure is applied to fluid retained within variable volume chambers 24 such that it may be expelled at outlet ports 32 at increased pressure if desired. During rotation, curved surface support elements 40 are held around rotatable shaft structure 12 such that the curved surface support elements 40 rotate with rotatable shaft structure 12 while nonetheless being slidable longitudinally relative to rotatable shaft structure 12. Biasing elements 60 continuously urge curved surface support elements 40 outwardly away from rotor 14 so as to maintain curved surface support element 40 at a desired position. The biasing force provided by biasing element 60 is also translated across the curved surface support elements 40 thereby pressing drum plates 18 against outboard face plates 34 to assist in maintaining leak free fluid passages.
The industrial applicability of the pump assembly described herein will be readily appreciated from the foregoing discussion. Pump assemblies consistent with the present disclosure may be used to convey fluids through various systems in an efficient manner while maintaining proper operative relation of the various components. By way of example only, and not limitation, exemplary fluids conveyed by the pump assembly may include cooling fluids, lubricating fluids and the like.
In practice, a pump assembly consistent with this disclosure may be utilized in environments such as industrial equipment, on highway vehicles and the like where substantial durability is required. In such environments, the use of biasing elements operating in conjunction with a slidingly engaged curved support element may tend to dampen vibrations and promote stability of operation. Moreover, in the event of damage, the separable curved support element may be replaced without the need to replace the rotatable shaft structure. Accordingly, maintenance may be substantially simplified.