Patent Application
20130336802
Historically, electric motor pumps used to power aircraft components have case drain circuits that carry away heat associated with pump and electric motor losses as well as heat associated with pressure drop in the system. Typically, forced hydraulic fluid cooling is used to keep the electric motor pumps cool. For example, relatively small gerotor pumps can be built onto the motor pump shafts to provide this positive cooling flow. With motor pumps operating in a constant electrical frequency system (typically 400 hertz), gerotor pumps, operating at constant shaft speeds are able to provide sufficient flow to provide the necessary cooling.
One aspect of the present disclosure relates to a fluid circuit that has a first pump assembly. The first pump assembly has an electric motor and a first fluid pump. The first fluid pump is coupled to the electric motor and has a first fluid inlet, a first fluid outlet, and a case drain port that is in fluid communication with a case drain region of the first fluid pump. The fluid circuit also has a second pump assembly in fluid communication with the first pump assembly. The second pump assembly is powered by hydraulic pressure from the first fluid outlet of the first fluid pump and functions to augment flow through the case drain region of the first fluid pump.
Another aspect of the present disclosure relates to an aircraft. The aircraft includes a first pump assembly and a cooling circuit in fluid communication with the first pump assembly. The cooling circuit includes a second pump assembly powered by hydraulic pressure output from the first pump assembly. The second pump assembly also augments flow through a case drain region of the first pump assembly.
In some implementations, an example second pump assembly includes a fluid motor and a second fluid pump coupled to the fluid motor. A fluid inlet of the motor is in fluid communication with the outlet of the first fluid pump so that fluid output from the first fluid pump powers the motor. An inlet of the second fluid pump is in fluid communication with the case drain port of the first fluid pump so that the second fluid pump pumps fluid from the case drain region of the first fluid pump when powered by the motor.
In other implementations, another example second pump assembly includes a pilot stage valve assembly and a main stage valve assembly in fluid communication with the pilot stage valve assembly. The pilot stage valve assembly has a fluid inlet passage in fluid communication with a first fluid outlet of the first fluid pump. The main stage valve assembly has a fluid inlet passage in fluid communication with the case drain port of the first fluid pump so that the second fluid pump assembly pumps fluid from the case drain region of the first fluid pump. In other implementations, another example second pump assembly includes a vane pump having a drive port in fluid communication with the outlet of the first pump assembly, an intake port in fluid communication with the case drain port of the first pump assembly, and an output port in fluid communication with a cooling circuit. The vane pump includes a rotor that rotates within a cam structure having a cam surface. The rotor defines radial slots in which vanes are slidably mounted. The vane pump also includes a chamber defined between the cam surface and the rotor. Fluid from the case drain port is drawn into the chamber and mixes with pressurized fluid from the first fluid outlet as the rotor rotates, and the mixture is pumped out of the vane pump through the output port.
In other implementations, another example second pump assembly includes at least three spool valves. At least one of the spool valves is coupled to a piston head within a piston chamber. Operation of the spool valves is coordinated to reciprocate the piston head within the piston chamber. The spools of the spool valves are moved back and forth between first and second positions using positive hydraulic pressure accessed from the first fluid outlet of the first fluid pump.
In other implementations, another example second pump assembly includes a sequencing valve and a main valve. The main valve includes a piston head that is reciprocated within a piston cylinder having first and second cylinder ports positioned on opposite sides of the piston head. The main valve and the sequencing valve are moved via hydraulic drive pressure accessed from the first fluid outlet of the first fluid pump. The sequencing valve includes a sequencing spool movable between a first position and a second position. When the sequencing spool is in the first position, the first cylinder port is in fluid communication with a first inlet port and the second cylinder port is in fluid communication with an outlet port. When the sequencing spool is in the second position, the first cylinder port is in fluid communication with the outlet port and the second cylinder port is in fluid communication with a second inlet port. The first and second inlet ports are in fluid communication with the case drain region of the first fluid pump.
A variety of additional aspects will be set forth in the description that follows. These aspects can relate to individual features and to combinations of features. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the broad concepts upon which the embodiments disclosed herein are based.
Reference will now be made in detail to the exemplary aspects of the present disclosure that are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like structure.
With the advent of electronically controlled motors for aircraft electric motor pumps, electric motor pumps can be operated at varying speeds ranging from maximum speed to near zero. Therefore, for many applications, cooling flow can no longer depend on gerotor pumps that are mechanically driven by the motor shafts of electric motor pumps. The present disclosure relates to techniques for providing adequate levels of cooling flow without mechanically coupling to the motor shaft of the motor pump to provide power for a supplemental pump used to augment cooling flow. Instead, a portion of the hydraulic fluid output from the aircraft motor pump can be used to hydraulically power a flow augmenting device that draws case drain fluid from a case drain region of the motor pump and pumps the case drain fluid through a cooling circuit.
The present disclosure also relates to a system that taps (i.e., accesses, uses, diverts, etc.) a relatively small amount of hydraulic fluid flow from a high pressure flow source (i.e., a driving flow source, a command flow source) and converts such flow into a driven hydraulic fluid flow (i.e., a resultant flow, an augmented flow, a reduced pressure flow, a de-intensified pressure flow, etc.) having a substantially higher flow rate and a substantially lower pressure than the tapped high pressure flow. In certain embodiments, the driving flow source can be the flow of hydraulic fluid output from a variable speed electric motor-pump, and the driven flow can be used to augment the flow of hydraulic fluid through the case drain of the variable speed electric motor-pump. The augmented case drain flow can be routed through a cooling circuit to provide cooling of the case drain fluid, cooling of the variable speed electric motor-pump, and cooling of relatively high power electronics used to control the variable speed electric motor-pump.
Another aspect of the present disclosure relates to a system including a first hydraulic fluid flow and a second hydraulic fluid flow. The second flow is depressurized as compared to the first flow. A portion of the first flow (i.e., a diverted flow portion, a command flow portion, a drive flow portion) is diverted from the first flow and used to power (i.e., drive) a flow augmenter (e.g., a pump) that generates the second flow. The hydraulic fluid flow generated by (i.e., outputted from) the flow augmenter has a lower pressure and a higher flow rate than the diverted flow portion of the first flow.
In some embodiments, the first flow is the output from a variable speed electric motor-pump, and the flow augmenter is used to augment hydraulic fluid flow through a case drain region of the variable speed electric motor-pump. The augmented case drain flow can be routed through a cooling circuit to provide cooling of the case drain fluid, cooling of the variable speed electric motor-pump, and cooling of relatively high power electronics used to control the variable speed electric motor-pump.
In certain embodiments, the flow augmenter can be designed such that the augmented flow has a pressure less than or equal to one-fifth the pressure of the diverted flow portion and the augmented flow has a flow rate greater than or equal to at least five times the flow rate of the diverted flow portion. In other embodiments, the flow augmenter can be designed such that augmented flow has a pressure less than or equal to one-tenth the pressure of the diverted flow portion and the augmented flow has a flow rate greater than or equal to at least ten times the flow rate of the diverted flow portion. In still other embodiments, the flow augmenter can be designed such that the augmented flow has a pressure less than or equal to one-fifteenth the pressure of the diverted flow portion and the augmented flow has flow rate greater than or equal to at least fifteen times the flow rate of the diverted flow portion.
Referring now to
Referring to
In the depicted embodiment, the motor 18 of the first fluid pump assembly 12 is a variable speed electric motor that is electronically controlled by electronic control circuitry 19 (e.g., an electronic controller, an electronic control module, an electronic control board or boards, etc.) so as to be operable at a variety of speeds ranging from near zero to a maximum speed. The motor 18 has a shaft 28 that is coupled to the first fluid pump 16 so that when the shaft 28 of the motor 18 rotates, a pumping kit of the first fluid pump 16 is actuated. As the pumping kit of the first fluid pump 16 is actuated, fluid is communicated from the first fluid inlet 20 to the first fluid outlet 22 of the first fluid pump 16. The first fluid pump 16 and the motor 18 can be integrated together with the electronic control circuitry 19 such that the first fluid pump assembly 12 forms a variable speed electric motor-pump unit (i.e., a motor-pump module, a motor-pump assembly, a motor-pump module, etc.).
The first fluid pump 16 of the first fluid pump assembly 12 further includes a case drain port 30. The case drain port 30 is in fluid communication with a case drain region in the first fluid pump 16. During normal operation of the first fluid pump 16, there is an amount of pressurized fluid that leaks from the pumping kit of the first fluid pump 16 to the case drain region. The fluid in the case drain region can be drained through the case drain port 30.
Referring still to
In a preferred embodiment, the case drain fluid outputted through the outlet port 39 is pumped through a cooling circuit line 41 for cooling the case drain fluid. The cooling circuit line 41 is in fluid communication with the outlet port 39 and extends to the reservoir 24. In the depicted embodiment, the cooling circuit line 41 includes a discrete heat exchanger 122 for enhancing cooling of case drain fluid pumped through the cooling circuit line 41. The heat exchanger 122 pulls heat out of the fluid passing through the cooling circuit line 41. In other embodiments, the length of hose or conduit defining the cooling circuit line 41 may have sufficient length and heat exchange properties to provide adequate cooling of the case drain fluid. In such embodiments, a separate discrete heat exchanger 122 is not needed. Instead, the length of hose or conduit itself functions as a heat exchanger. In certain embodiments, a fluid filter 128 can be used to filter the fluid passing through the cooling circuit line 41 to reservoir 24.
In the depicted embodiment, the second fluid pump assembly 32 is not mechanically driven/powered by the shaft 28 of the motor 18. Instead, power for driving the second pump assembly 32 is derived from relatively high pressure hydraulic fluid flow accessed from the fluid output from the first fluid pump 16. For example, as shown at
In a preferred embodiment, the second fluid pump assembly 32 is designed to use a relatively small amount of high pressure flow from the main output flow line 27 to provide power for generating cooling flow, which has a substantially lower pressure and a substantially higher flow rate than the pressure and flow rate of the flow diverted from the main output flow line 27. For example, in certain embodiments, the cooling circuit 14 can have a hydraulic fluid flow rate that is at least 5, 10, or 15 times as large as the flow rate of the diverted flow; and the output from the second fluid pump assembly 32 can have a hydraulic pressure less than or equal to ⅕, 1/10, or 1/15 the hydraulic pressure of the hydraulic fluid output from the first fluid pump 16. In one example embodiment, the pressure of the fluid carried through the drive line 47 is about 3000 pounds per square inch (psi), the flow rate in the drive line 47 is about 0.1 gallons per minute, the pressure of the casing drain fluid output from the second pump assembly 32 is less than about 200 (psi), and the flow rate through the cooling line 41 is about 1.5 gallons per minute.
It will be appreciated that the motor 18 and electronic control circuitry 19 of the first fluid pumping assembly 12 can generate a substantial amount of heat. To cool the first fluid pumping assembly 12, cooling flow can be directed across, through or along portions of the first fluid pumping assembly 12. For example,
As shown in
The fluid motor 34 includes a fluid inlet 38 and a fluid outlet 40. The fluid inlet 38 of the fluid motor 34 is in fluid communication with the drive port 45 of the second fluid pump assembly 132, which is in fluid communication with the first fluid outlet 22 of the first fluid pump 16 via drive line 47. Only a first portion of the fluid from the first fluid outlet 22 of the first fluid pump 16 is communicated to the drive port 45 and, hence, to the fluid inlet 38 of the fluid motor 34. A second portion (e.g., the remaining portion) of the fluid from the first fluid outlet 22 of the first fluid pump 16 is communicated to the downstream components 26. In one embodiment, a flow divider is used to split the fluid from the first fluid outlet 22 of the first fluid pump 16 into the first and second portions.
The fluid motor 34 further includes an output shaft 42. As fluid passes from the fluid inlet 38 to the fluid outlet 40 of the fluid motor 34, the output shaft 42 rotates. The output shaft 42 of the fluid motor 34 is coupled to the second fluid pump 36. The second fluid pump 36 includes a second fluid inlet 44 and a second fluid outlet 46. The second fluid pump 36 also includes a pumping element. The pumping element can be one of various types of pumping elements including a gerotor-type, a vane-type, an axial piston-type, a radial piston-type, a reciprocating piston type, etc. As the second fluid pump 36 is coupled to the fluid motor 34, rotation of the output shaft 42 causes fluid to be communicated (i.e., pumped) from the second fluid inlet 44 of the second fluid pump 36 to the second fluid outlet 46 of the second fluid pump 36.
The second fluid inlet 44 of the second fluid pump 36 is in fluid communication with the case drain port 30 of the first fluid pump 16 along a fluid conduit 48 (e.g., hose, tubing, etc.). The fluid conduit 48 provides a passage through which fluid is communicated from the case drain port 30 of the first fluid pump 16 to the second fluid inlet 44 of the second fluid pump 36. In certain implementations, the second fluid inlet 44 of the second fluid pump 36 is in direct communication with the case drain port 30 of the first fluid pump 16. In the depicted embodiment, the fluid conduit 48 includes case drain fluid line 37.
Fluid from the case drain region of the first fluid pump 16 is communicated to the second fluid inlet 44 of the second fluid pump 36 through the case drain port 30 of the first fluid pump 16 and the fluid conduit 48 as the output shaft 42 of the fluid motor 34 rotates. In the depicted embodiment, fluid from the fluid outlet 40 of the fluid motor 34 is in fluid communication with the second fluid inlet 44 of the second fluid pump 36. In the depicted embodiment, fluid from the fluid outlet 40 of the fluid motor 34 is in fluid communication with the fluid conduit 48.
Fluid from the case drain region of the first fluid pump 16 is pumped to the fluid reservoir 24 through the second fluid outlet 46 of the second fluid pump 36. In the depicted embodiment, the fluid passes through a heat exchanger 122 and a fluid filter 128 before reaching the reservoir 24. The heat exchanger 122 is adapted to draw heat from the fluid. The fluid filter 128 is adapted to filter contaminants of a particular particle size from the fluid before the fluid enters the fluid reservoir 24. Additional heat exchangers 122 can be provided along the cooling line 141 to transfer heat out of the system, thereby cooling the fluid carried through the cooling line 141. In an alternate embodiment, the filter 128 is disposed between the fluid reservoir 24 and the first fluid inlet 20 of the first fluid pump 16. In certain implementations, the fluid is passed through a heat exchanger 49 (e.g., see
Referring now to
In step 204, the second fluid inlet 44 of the second fluid pump 36 is connected to the case drain port 30 of the first fluid pump 16. As the fluid motor 34 is coupled to the second fluid pump 36, actuation of the fluid motor 34 causes fluid in the case drain region of the first fluid pump 16 to be pumped out of the first fluid pump 16 by the second fluid pump 36. In the depicted embodiment, the fluid motor 34 is coupled to the second fluid pump 36 by the output shaft 42. In the depicted embodiment, the second fluid pump 36 is connected to the case drain port 30 by the fluid conduit 48.
In step 206, the fluid outlet 40 of the fluid motor 34 is in fluid communication with the second fluid inlet 44 of the second fluid pump 36. In the depicted embodiment, the fluid outlet 40 of the fluid motor 34 is coupled to the fluid conduit 48. In step 208, the second fluid outlet 46 of the second fluid pump 36 is connected to an inlet 121 of the heat exchanger 122. In one embodiment a conduit (e.g., hose, tube, pipe, etc.) provides the connection between the second fluid outlet 46 and the inlet 122.
In step 210, an outlet 123 of the heat exchanger 122 is connected to an inlet 127 of the filter 128. In one embodiment a conduit (e.g., hose, tube, pipe, etc.) provides the connection between the outlet 123 and the inlet 127. In step 212, an outlet 129 of the filter 128 is connected to the reservoir 24.
Referring now to
The first valve housing 238 further defines a fluid inlet passage 50 that is in fluid communication with the first spool bore 142, a first control passage 52, a second control passage 54, a first pilot passage 56 that is in fluid communication with the first axial end 144 of the first spool bore 142, and a second pilot passage 58 that is in fluid communication with the second axial end 146 of the first spool bore 142. In the depicted embodiment, the fluid inlet passage 50 has an opening at the first spool bore 142 that is between spool bore openings for the first and second control passages 52, 54. In the depicted embodiment, the opening for the first control passage 52 is disposed between the first axial end 144 of the first spool bore 142 and the opening for the fluid inlet passage 50. The opening for the second control passage 54 is disposed between the second axial end 146 of the first spool bore 142 and the opening for the fluid inlet passage 50.
In the depicted embodiment, the first valve housing 238 further includes a first fluid outlet passage 60 and a second fluid outlet passage 62. The first and second fluid outlet passages 60, 62 are in fluid communication with the fluid reservoir 24. An opening at the first spool bore 142 for the first fluid outlet passage 60 is disposed between the first axial end 144 of the first spool bore 142 and the opening for the first control passage 52. An opening at the first spool bore 142 for the second fluid outlet passage 62 is disposed between the second axial end 146 of the first spool bore 142 and the opening for the second control passage 54.
The pilot stage valve 140 is generally cylindrical in shape and is adapted to slide within the first spool bore 142 in an axial direction along the central longitudinal axis 148. The pilot stage valve 140 includes a first end 64 and an oppositely disposed second end 66. The pilot stage valve 140 includes a first land 68 disposed adjacent the first end 64, a second land 70 disposed adjacent the second end 66, and a third land 72 disposed between the first and second lands 68, 70. The first and third lands 68, 72 are adapted to provide selective fluid communication between the first control passage 52 and one of the fluid inlet passage 50 and the first fluid outlet passage 60. The second and third lands 70, 72 are adapted to provide selective fluid communication between the second control passage 54 and one of the fluid inlet passage 50 and the second fluid outlet passage 62.
The pilot stage valve 140 is adapted to move between a first position (shown in
The main stage valve assembly 236 includes a second valve housing 74 and a main stage valve 76 disposed in the second valve housing 74. In one embodiment, the first valve housing 238 of the pilot stage valve assembly 234 and the second valve housing 74 of the main stage valve assembly 236 are a single unitary housing such as a valve block. In another embodiment, the first valve housing 238 of the pilot stage valve assembly 234 and the second valve housing 74 of the main stage valve assembly 236 are separate valve housings that are connected together via hoses, tubes, or pipes. In another embodiment, the first and second valve housings 238, 74 are directly connected together by fasteners (e.g., bolts, screws, welds, etc.).
The second valve housing 74 defines a second spool bore 78 in which the main stage valve 76 is slidably disposed. The second spool bore 78 includes a first axial end 80 and an oppositely disposed second axial end 82. The second spool bore 78 defines a central longitudinal axis 84 that extends between the first and second axial ends 80, 82. In the depicted embodiment, the second spool bore 78 includes a pumping chamber 86. The pumping chamber 86 of the second spool bore 78 is disposed between the first and second axial ends 80, 82. In the depicted embodiment, an inner diameter of the pumping chamber 86 is greater than an inner diameter of the first axial end 80 and an inner diameter of the second axial end 82.
The second valve housing 74 further defines a fluid inlet passage 88 that is in fluid communication with the pumping chamber 86 of the second spool bore 78, a first control passage 90 that is in fluid communication with the second axial end 82 of the second spool bore 78, a second control passage 92 that is in fluid communication with the first axial end 80 of the second spool bore 78, a first pilot passage 94, and a second pilot passage 96. The second valve housing 74 further includes a fluid outlet passage 98 that is in fluid communication with the pumping chamber 86 of the second spool bore 78. The fluid outlet passage 98 is in fluid communication with the fluid reservoir 24.
In the depicted embodiment, a first check valve 100a is disposed in the fluid inlet passage 88 and a second check valve 100b is disposed in the fluid outlet passage 98. The first and second check valves 100a, 100b are adapted to allow fluid to flow through the fluid inlet passages 88 and the fluid outlet passages 98 in only one direction.
The second valve housing 74 further defines a first fluid outlet passage 102 and a second fluid outlet passage 104. The first fluid outlet passage 102 is disposed between the pumping chamber 86 and the first pilot passage 94. The second fluid outlet passage 104 is disposed between the pumping chamber 86 and the second pilot passage 96. The first and second fluid outlet passages 102, 104 are in fluid communication with the fluid reservoir 24. In one embodiment, check valves are disposed in the first and second outlet passages 102, 104.
The first control passage 90 of the main stage valve assembly 236 is in fluid communication with the first control passage 52 of the pilot stage valve assembly 234. The second control passage 92 of the main stage valve assembly 236 is in fluid communication with the second control passage 54 of the pilot stage valve assembly 234. The first and second pilot passages 94, 96 of the main stage valve assembly 236 are in fluid communication with the first and second pilot passages 56, 58, respectively, of the pilot stage valve assembly 234.
The main stage valve 76 is generally cylindrical in shape and is adapted to slide within the second spool bore 74 in an axial direction along the central longitudinal axis 84. The main stage valve 76 includes a first end 106 and an oppositely disposed second end 108. The main stage valve 76 includes a first land 110 disposed adjacent the first end 106, a second land 112 disposed adjacent the second end 108, and a piston 114 disposed between the first and second lands 110, 112.
The first land 110 is adapted to provide selective fluid communication between the first pilot passage 94 and one of the second control passage 92 and the first fluid outlet passage 102. The second land 112 is adapted to provide selective fluid communication between the second pilot passage 96 and one of the first control passage 90 and the second fluid outlet passage 104. The piston 114 is disposed in the pumping chamber 86 of the second spool bore 74. The piston 114 separates the pumping chamber 86 into a first volume chamber 116a and a second volume chamber 116b. The first and second volume chambers 116a, 116b expand and contract as the main stage valve 76 moves axially in the second spool bore 78.
The main stage valve 76 is adapted to move between a first position (shown in
As the main stage valve 76 is actuated to the second position, fluid from the fluid inlet passage 88 enters the first volume chamber 116a of the pumping chamber 86 while fluid in the second volume chamber 116b is expelled to the fluid outlet passage 98. The main stage valve 76 is actuated from the first position to the second position by fluid from the second control passage 54 of the pilot stage valve assembly 234, which is in fluid communication with the second control passage 92 of the main stage valve assembly 236, acting against the first end 106 of the main stage valve 76.
Referring now to
In step 254, the fluid inlet passage 88 of the main stage valve assembly 236 is connected to the case drain port 30 of the first fluid pump 16. Actuation of the piston 114 causes fluid in the case drain region of the first fluid pump 16 to be pumped out of the first fluid pump 16 by the main stage valve assembly 236. In the depicted embodiment, the main stage valve assembly 236 is connected to the case drain port 30 by a fluid conduit 118 (e.g., a hose, tube, etc.). In step 256, the first and second fluid outlet passages 60, 62 of the pilot stage valve assembly 234 are connected to the fluid reservoir 24.
In step 258, the fluid outlet passage 98 of the main stage valve assembly 236 is connected to an inlet 121 of the heat exchanger 122. In one embodiment a conduit (e.g., hose, tube, pipe, etc.) provides the connection between the fluid outlet passage 98 and the inlet 121. In step 260, an outlet 123 of the heat exchanger 122 is connected to an inlet 127 of a filter 128. In one embodiment a conduit (e.g., hose, tube, pipe, etc.) provides the connection between the outlet 123 and the inlet 127. In step 262, an outlet 129 of the filter 128 is connected to the reservoir 24.
Referring now to
A first portion of the fluid from first fluid outlet 22 of the first fluid pump 16 enters the fluid inlet passage 50 of the pilot stage valve assembly 234. With the pilot stage valve 140 in the first position (e.g., as shown in
As the main stage valve 76 moves toward the second position from the first position, the first volume chamber 116a of the pumping chamber 86 expands while the second volume chamber 116b contracts. As the first volume chamber 116a expands, fluid from the case drain port 30 of the first fluid pump assembly 16 enters the first volume chamber 116a of the pumping chamber 86 of the main stage valve assembly 236 through the fluid inlet passage 88. As the second volume chamber 116b contracts, fluid in the second volume chamber 116b is expelled through the fluid outlet passage 98.
When the first land 110 of the main stage valve 76 uncovers an opening to the first pilot passage 94 of the main stage valve assembly 236, fluid is communicated from the second control passage 92 of the main stage valve assembly 236 to the first pilot passage 56 of the pilot stage valve assembly 234. The fluid from the first pilot passage 56 acts against the first end 64 of the pilot stage valve 140 so that the pilot stage valve 140 moves in an axial direction toward the second position.
Referring now to
As the main stage valve 76 moves toward the first position from the second position, the second volume chamber 116b of the pumping chamber 86 expands while the first volume chamber 116a contracts. As the second volume chamber 116b expands, fluid from the case drain port 30 of the first fluid pump assembly 16 enters the second volume chamber 116b of the pumping chamber 86 of the main stage valve assembly 236 through the fluid inlet passage 88. As the first volume chamber 116a contracts, fluid in the first volume chamber 116a is expelled through the fluid outlet passage 98.
When the second land 112 of the main stage valve 76 uncovers an opening to the second pilot passage 96 of the main stage valve assembly 236, fluid is communicated from the first control passage 90 of the main stage valve assembly 236 to the second pilot passage 58 of the pilot stage valve assembly 234. The fluid from the second pilot passage 58 acts against the second end 66 of the pilot stage valve 140 so that the pilot stage valve 140 moves in an axial direction toward the first position.
Referring now to
The cam ring structure 324 is configured for allowing the vane pump 320 to concurrently function as both a pump and a motor. In a preferred embodiment, motive force for turning the rotor 322 in the clockwise direction 325 within the cam ring structure 324 is provided by using hydraulic pressure from the first fluid outlet 22 of the first fluid pump 16 (
The fluid drawn from the case drain port 30 as well as the fluid from the first fluid outlet 22 used to drive the rotor 322 are combined within the vane pump 320 and then pumped outwardly from the vane pump 320 to the heat exchanger 122 where the fluid is cooled. Thereafter, the fluid flows through the filter 52 back to the reservoir 24 of the fluid circuit 10. It will be appreciated that the reservoir 24 is in fluid communication with the first fluid pump 16 and the heat exchanger 122 (
Referring still to
Motor regions 348 of the motor/pump chambers 338 coincide with the first ascending portions 346a, fluid intake regions 347 of the motor/pump chambers 338 coincide with the second ascending portions 346b, and output regions 355 of the motor/pump chambers 338 coincide with the descending portions 352. The ascending portions 346a, 346b of the cam surface 333 transition gradually away from (i.e., further from) the axis of rotation 326 as the ascending portions 346a, 346b extend in the clockwise direction 325 about the axis of rotation 326. The descending portions 352 of the cam surface 333 transition gradually toward (i.e., closer to) the axis of rotation 326 as the descending portions 352 extend in the clockwise direction 325 about the axis of rotation 326.
The dwell surfaces 341 are defined by constant radii swung about the axis of rotation 326 and therefore maintain a constant spacing from the axis of rotation 326 as the dwell surfaces extend in the clockwise direction 325 about the axis of rotation 326. The radii of the intermediate dwell surfaces 344 are larger than the radii of the minor dwell surfaces 340, and the radii of the major dwell surfaces 341 are larger than the radii of the intermediate dwell surfaces 344. A cam profile for the cam surface 334 of one of the two identical motor/pump chambers 338 is shown at
The cam ring structure 324 includes high pressure passages 356 that are connected in fluid communication with the first fluid outlet 22 of the first fluid pump 16 (
The cam ring structure 324 further includes output passages 364 connected in fluid communication with the heat exchanger 122 of the cooling circuit by a fluid line 365 that extends from the heat exchanger 122 of the cooling circuit 14, 14′ to an output port 366 of the vane pump 320. The high pressure passages 356 provide fluid communication between the motor regions 348 of the motor/pump chambers 338 and the high pressure port 358 of the vane pump 320. The intake passages 360 provide fluid communication between the intake regions 347 of the motor/pump chambers 338 and the intake port 362 of the vane pump 320. The output passages 364 provide fluid communication between the output regions 355 of the motor/pump chambers 338 and the output port 366 of the vane pump 320.
In use of the vane pump 320, a portion of the high pressure fluid from the first fluid outlet 22 of the first fluid pump 16 (e.g., in one embodiment fluid at a pressure of about 3,000 pounds per square inch (psi)) is directed through a diverter to the fluid line 357. The fluid line 357 carries the high pressure fluid to the high pressure port 358 of the vane pump 320. From the high pressure port 358, the high pressure fluid travels through the high pressure passages 356 to the motor regions 348 of the motor/pump chambers 338. The high pressure fluid directed into the motor regions 348 through the high pressure passages 356 acts upon the vanes 330 at the motor regions 348 of the motor/pump chambers 338. This pressure applied against the vanes 330 at the motor regions 348 of the motor/pump chambers 338 provides the motive force necessary to rotate the rotor 322 in the clockwise direction 325 about the axis of rotation 326.
Rotation of the rotor 322 in the clockwise direction causes lower pressure fluid from the case drain port 30 of the first fluid pump 16 (e.g., in one embodiment fluid at about 50 psi) to be drawn from the intake passages 360 into the intake regions 347 of the motor/pump chambers 338. At the intake regions 347 of the motor/pump chambers 338, the high pressure fluid from the first fluid outlet 22 mixes with the lower pressure fluid from the case drain port 30. As the rotor 322 continues to rotate about the axis of rotation 326, the mixture of high pressure fluid and lower pressure fluid is compressed to an intermediate pressure (e.g., in one embodiment about 200 psi) in the output regions 355 of the motor/pump chambers 338 and forced out the output passages 364 to the heat exchanger 50 where the fluid is cooled. Upon exiting the heat exchanger 122, the fluid flows through the filter 128 back to the reservoir 24 (see
The cam ring structure 404 includes a cam surface 412 that surrounds the rotor 402 and opposes an outer circumferential surface 413 of the rotor 402. The vane pump 401 defines two oppositely positioned pump chambers 414. The pump chambers 414 are defined between the cam surface 412 of the cam ring structure 404 and the outer circumferential surface 413 of the rotor 402. The cam surface 412 includes two oppositely disposed ascending portions 416 and two oppositely disposed descending portions 418. The ascending and descending portions 416, 418 of each of the pump chambers 414 are separated by a major dwell surface 420. Minor dwell surfaces 422 separate the two pump chambers 414 from one another. A cam profile for one of the chambers 414 is provided at
Intake regions 417 of the pump chambers 414 coincide with the ascending portions 416 and output regions 419 of the pump chambers 414 coincide with the descending portions 418. The cam ring structure 404 includes intake passages 460 that are connected in fluid communication with the case drain port 30 of the first fluid pump 16 (
The cam ring structure 404 defines a manifold including a first quadrant 430a, a second quadrant 430b, third quadrant 430c and a fourth quadrant 430d. The first and third quadrants 430a, 430c define a higher pressure passage structure 432 (e.g., a passage, passages or other defined volume) having portions that are in fluid communication with the inner ends 408 of the radial slots 406 and that radially align with the ascending portions 416 of the cam surface 412. The higher pressure passage structure 432 is also in fluid communication with a drive port 437 of the vane pump 401. The second and fourth quadrants 430b, 430d include a lower pressure passage structure 434 having portions that are in fluid communication with the inner ends 408 of the radial slots 406 and that radially align with the descending portions 418 of the cam surface 412. The higher pressure passage structure 432 is in fluid communication with the fluid outlet 22 of the first fluid pump 16 (e.g. via a flow line 435 that extends from the drive port 437 of the vane pump 401 to a flow divider in fluid line 27 of
In use of the vane pump 401, the inner ends 408 of the radial slots 406 are alternatingly brought into fluid communication with the higher pressure passage structure 432 and the lower pressure passage structure 434 as the rotor 402 rotates in the clockwise direction 405 about the rotation axis 403. The higher relative fluid pressure provided by the higher pressure passage structure 432 as compared to the lower pressure passage structure 434 causes the vanes 410 to be forced against the ascending portions 416 of the cam surface 412 at a higher force than the vanes 410 are forced against the descending portions 418 of the cam surface 412. The ascending portions 416 are angled relative to the vanes 410 such that when the outer ends 411 of the vanes 410 are driven against the ascending portions 416, a motive force (e.g., a clockwise torque) is applied to the rotor 402. The descending portions 418 are angled relative to the vanes 410 such that when the outer ends 411 are driven against the descending portions 418, a counterclockwise torque is applied to the rotor 402.
Because the vanes 410 are forced against the ascending portions 416 at a higher relative force than the vanes 410 are forced against the descending portions 418, a net clockwise torque is applied to the rotor 402 which causes clockwise rotation of the rotor 402. As the rotor 402 rotates in the clockwise direction 405, fluid from the case drain port 30 (
Referring now to
In some implementations, the cooling circuit line 41 fluidly connects to the outlet port 39 of the fifth assembly 500. The cooling circuit line 41 transfers heat out of the system/circuit before returning flow back to the reservoir 24 of the fluid circuit. In other implementations, the cooling circuit line 41′ can also be used to carry further heat away from the control electronics of the variable speed motor-pump unit 12 as shown at
Referring to
The first spool valve 510, the second spool valve 512, and the third spool valve 514 each preferably include an unbalanced spool. The spools are unbalanced by providing piloting surfaces having different sized pilot areas at opposite ends of the spools (e.g., major and minor pilot areas). The valve arrangement incorporates positive sequencing to control the reciprocating action of the piston 516 while eliminating the need for inertial loading to maintain operation of the spool valves. For example, each spool position is preferably attained through an axial force originating from hydraulic pressure accessed from the first fluid pump 16 (
The first spool valve 510 includes a first spool 524 that is reciprocally removable along a first slide axis 526 between a first position (see
The valve body 501 defines a minor pilot passage 528 that places the minor pilot surface 524b in constant fluid communication with the drive line 47 through the drive port 45. In contrast, the major pilot surface 524a is alternatingly placed in fluid communication with the drive port 45 and the return port 502. When the major pilot surface 524a is in fluid communication with the drive port 45, a larger piloting force is provided at the major pilot surface 524a as compared to the minor pilot surface 524b thereby causing the first spool 524 to move to the first position of
The second spool valve 512 includes a second spool 530 that can reciprocate along a second slide axis 532. Movement of the second spool 530 along the second slide axis 532 causes simultaneous movement of the piston head 520 within the piston cylinder 522. The second spool 530 includes a major pilot surface 530a and a minor pilot surface 530b. The major and minor pilot surfaces 530a, 530b are positioned at opposite ends of the second spool 530 and face in opposite axial directions. The major pilot surface 530a has a larger pilot area as compared to the minor pilot surface 530b.
The second spool 530 is movable along the second slide axis 532 between a first position (see
It will be appreciated that the diameter of the piston head 520 is designed in coordination with pilot areas of the major and minor pilot surfaces 530a, 530b. For example, by selecting a piston head 520 having larger axial end face areas as compared to the pilot areas of the major and minor pilot surfaces 530a, 530b, the fifth assembly 500 can be designed to output flow through the outlet port 39 having a higher flow rate and a lower pressure as compared to the flow provided to the fifth pump assembly 500 through the drive port 45 (see
The third spool valve 514 includes a third spool 540 that reciprocates back and forth along a third slide axis 542. The third spool 540 is movable along the third slide axis 542 between a first position (see
The first spool valve 510 controls whether the major pilot surface 530a of the second spool 530 is placed in fluid communication with the drive port 45 or the return port 502. The first spool valve 510 also controls the fluid connections between the first and second fluid ports 521, 523 of the piston cylinder 522 and the intake and outlet ports 35, 39 of the valve body 501. For example, when the first spool 524 of the first spool valve 510 is in the first position of
The second spool 530 is used to reciprocate the piston 516 within the piston cylinder 522. When the second spool 530 is in the first position of
The second spool 530 also controls the pressure provided to the major pilot surface 540a of the third spool 540. For example, when the second spool 530 is in the first position of
The third spool valve 514 functions to control the pressure provided to the major pilot surface 524a of the first spool valve 510. For example, when the third spool 540 is in the first position of
As the piston 516 moves in the second direction 556, the piston head 520 moves away from the fluid port 523 and towards the fluid port 521. This movement causes case drain fluid to be drawn into the piston cylinder 522 through the fluid port 523 and to be expelled from the piston cylinder 522 through the fluid port 521. With the first spool 524 in the second position, the port 523 is in fluid communication with the intake port 35 and the port 521 is in fluid communication with the outlet port 39. The piston 516 and the second spool 530 continue to move in the second direction 556 until the second spool 530 reaches the second position as shown at
With the third spool 540 in the second position as shown at
Referring now to
Referring to
In operation, the piston head 626 is reciprocated back and forth within the piston cylinder 628 along the second axis 622. When the piston head 626 moves in a first direction 634 within the piston cylinder 628, case drain fluid is drawn into the piston cylinder 628 through the piston cylinder port 630 and case drain fluid that had been previously drawn into the piston cylinder 628 is expelled through the piston cylinder port 632. In contrast, when the piston head 628 is moved in a second direction 636 within the piston cylinder 628, case drain fluid is drawn into the piston cylinder 628 through the piston cylinder port 632 and case drain fluid that had been previously drawn into the piston cylinder 628 is expelled through the piston cylinder port 630. In this way, the piston head 626 and the piston cylinder 628 function as a reciprocating pump that continuously draws case drain fluid from the case drain fluid line 37 into the sixth assembly 600 and also continuously pumps case drain fluid out of the sixth assembly 600 into the cooling circuit line 41.
Referring to
The valve body 601 defines a first set of bore ports at one side 617 of the first spool bore 616 and a second set of bore ports at an opposite side 619 of the first spool bore 616. The first set of bore ports includes five ports 656-660 and the second set of bore ports includes four bore ports 661-664. The bore ports 656-660 are spaced consecutively along the length of the first spool bore 616. Similarly, second set of spool bores 661-664 are spaced consecutively along the first spool bore 616. Bore port 656 is in constant fluid communication with the first inlet pressure bore port 602a, port 657 is in constant fluid communication with the outlet port 39, bore port 658 is in constant fluid communication with the second inlet pressure port 602b, bore port 659 is in constant fluid communication with the drive port 45, and bore port 660 is in constant fluid communication with the third inlet pressure port 602c. Bore port 661 is positioned generally between bore ports 656 and 657. Bore port 662 is positioned generally between bore port 657 and bore port 658. Bore port 663 is positioned generally between bore port 658 and bore port 659, and bore port 664 is positioned generally between bore port 659 and bore port 660. The first spool bore 616 also includes a pilot flow region 666 positioned adjacent the pilot surface 614a and a pilot flow region 668 positioned adjacent the pilot surface 614b.
The second spool 620 includes two end lands 670, 672 positioned at opposite ends of the second spool 620. The second spool 620 also includes pilot surfaces 620a, 620b positioned at opposite ends of the second spool 620. The pilot surfaces 620a, 620b face in opposite axial directions. The second spool bore 624 defines pilot regions 674, 676 positioned respectively adjacent to the pilot surfaces 620a, 620b. The second spool bore 624 also includes a bore port 678 positioned generally midway between the pilot region 674 and the piston cylinder 628 and a bore port 680 positioned generally midway between the pilot region 676 and the piston cylinder 628.
Various flow lines provide fluid communication between the first spool bore 616 and the second spool bore 624. For example, flow line 682 fluidly connects pilot region 666 of the first spool bore 616 to bore port 678 of the second spool bore 624. Also, flow line 684 fluidly connects pilot region 668 of the first spool bore 616 to bore port 680 of the second spool bore 624. Further, flow line 686 fluidly connects bore port 661 of the first spool bore 616 to piston cylinder port 630 and flow line 688 fluidly connects bore port 662 of the first spool bore 616 to piston cylinder port 632. Additionally, flow line 690 fluidly connects bore port 663 of the first spool bore 616 to pilot region 676 of the second spool bore 624 and flow line 692 fluidly connects bore port 664 of the first spool bore 616 to pilot region 674 of the second spool bore 624. Also, flow line 694 fluidly connects ports 696 and 698 of the second spool bore 624 to the third inlet pressure port 602c.
The first spool 614 is moveable within the first spool bore 616 between a first position (see
When the first spool 614 is in the second position of
The second spool 620 is also moveable within the second spool bore 624 between a first position (see
When the second spool 620 reaches the second position of
With the first spool 614 in the second position of
When the second spool 620 reaches the first position of
It will be appreciated that the diameter of the piston head 626 is designed in coordination with the surface areas defined by the pilot surfaces 620a, 620b. For example, by selecting a piston head 626 having substantially larger axial end face areas as compared to the areas of the pilot surfaces 674, 676, the sixth assembly 600 outputs flow through the outlet port 39 having a higher flow rate and a lower pressure as compared to the flow provided to the sixth assembly 600 through the drive port 45.
Various modifications and alterations of this disclosure will become apparent to those skilled in the art without departing from the scope and spirit of this disclosure, and it should be understood that the scope of this disclosure is not to be unduly limited to the illustrative embodiments set forth herein.
This application is being filed on 15 Dec. 2011, as a PCT International Patent application in the name of Eaton Corporation, a U.S. national corporation, applicant for the designation of all countries except the U.S., and, Phillip Wayne Galloway, a citizen of the U.S., Jeffrey David Skinner, Jr., a citizen of the U.S., and Kelly Dale Valtr, a citizen of the U.S., applicants for the designation of the U.S. only, and claims priority to U.S. Patent Application Ser. No. 61/427,904 filed on 29 Dec. 2010, U.S. Patent Application Ser. No. 61/428,184 filed on 29 Dec. 2010, U.S. Patent Application Ser. No. 61/487,530 filed on 18 May 2011, U.S. Patent Application Ser. No. 61/503,409 filed on 30 Jun. 2011, and U.S. Patent Application Ser. No. 61/503,429 filed on 30 Jun. 2011, the disclosures of which are incorporated herein by reference in their entirety.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US2011/065164 | 12/15/2011 | WO | 00 | 8/28/2013 |
| Number | Date | Country | |
|---|---|---|---|
| 61428184 | Dec 2010 | US | |
| 61427904 | Dec 2010 | US | |
| 61487530 | May 2011 | US | |
| 61503409 | Jun 2011 | US | |
| 61503429 | Jun 2011 | US |
