PUMP ASSEMBLY HAVING TWO PUMPS PROVIDED IN A SINGLE HOUSING
A pump assembly that has a first pump and a second pump for pumping lubricant, both pumps being integrated into a single housing. A drive shaft is provided that drives both pumps. Both the first pump and the second pump have a gear or rotor that is rotated by the drive shaft. Each of the pumps have an inlet provided on the housing to receive input from a source outside the housing and an outlet. The housing has a wall that is common to both pumps. The first pump is provided on a first side of the wall and the second pump is provided on the second, opposite side. The gears or rotors of the pumps may be provided in pockets provided on the first and second sides of the wall. The drive shaft extends through the wall and connects to each of the drive gears or rotors.
This application claims priority to U.S. Provisional Patent Application No. 62/786,961, filed Dec. 31, 2018, which is hereby incorporated by reference herein in its entirety.
BACKGROUND FieldThe present disclosure is generally related to a two stage pump assembly that includes a first pump and a second pump containing in a single housing.
Description of Related ArtDual pump systems that include more than one pump are generally known in the art. In some cases, these systems are designed to use one pump in certain circumstances, and another, different pump in other circumstances. U.S. Publication No. 20170058895 and U.S. Pat. No. 4,519,755 provide examples of these type of systems that use a second pump for pumping in certain circumstances. In some cases, the output of the pump is variable. See, e.g., U.S. Publication Nos. 20090041593 and 20110129359 for such examples of varying output from a pump.
SUMMARYIt is an aspect of this disclosure to provide a two stage pump assembly. The assembly includes: a first pump and a second pump for pumping lubricant, both the first pump and the second pump being integrated into a single housing and each configured to pressurize lubricant input into the housing. A drive shaft is provided in the housing configured to rotate about a drive axis and drive both the first pump and the second pump. The drive shaft is driven by a single input device. Both the first pump and the second pump have at least one gear configured and arranged to be rotated by the drive shaft. The first pump has a first inlet provided on the housing for receiving lubricant from a source outside the housing and a first outlet for directing lubricant that is pressurized out of the housing. The second pump has a second inlet provided on the housing for receiving lubricant from the source outside the housing and a second outlet for directing lubricant that is pressurized out of the housing. The second inlet and the second outlet are different than the first inlet and the first outlet, respectively. The housing further includes a wall that is common (or common wall) to both the first pump and the second pump, the first pump being provided on a first side of the wall and the second pump being provided on a second side of the wall that is opposite to the first side. The drive shaft extends through the wall and connects to each of the at least one gears of both the first pump and the second pump.
Another aspect of this disclosure provides the above noted two stage pump assembly with a transmission (or other system designed to receive pressurized lubricant from the pump assembly). The second pump is configured to continuously pump the lubricant to the transmission/system. In an embodiment, the transmission comprises a clutch system that selectively receives lubricant pumped from the first pump. A control valve may be provided for limiting the lubricant that is output from the first pump to the clutch system of the transmission.
Other features, improvements, and advantages of the present disclosure will become apparent from the following detailed description, the accompanying drawings, and the appended claims.
The pump assembly described herein contains multiple pumps within in a single housing or block. Each pump is provided with distinct inlets and outlets that allow for selective output from one of the pumps, while the other pump regularly or continuously supplies/outputs pressurized lubricant to a system (e.g., transmission or engine) during operation. A common wall is provided in the housing, between parts of the two pumps, and forms part of the internal chambers for each pump.
In accordance with an embodiment, the herein disclosed pump assembly includes a low pressure pump and high pressure pump (that is, two stages of pressure) that are configured to be driven off the same drive shaft. In accordance with one embodiment, the herein disclosed pump assembly includes a low pressure gerotor pump and a pressure-compensated, high pressure external gear pump that are paired together and configured to be driven off the same drive shaft.
While there are parts and features of the pump assembly 10 herein referenced as top, bottom, left, right, upper, lower, first, second, etc., it should be noted that such terms are not at all intended to be limiting with respect to direction, mounting, or positioning of the housing 12 and/or pump assembly 10 described herein. Such terms are provided for reference only.
In accordance with an embodiment, the “two-stages” addressed by the disclosed pump assembly refer to the pump assembly 10 being able to provide two stages of pressure levels, i.e., a first, higher pressure and a second, lower pressure. That is, in some embodiments, a first pump 20 and a second pump 30 are provided for pumping lubricant (e.g., oil); each pump is configured to pressurize lubricant input into the housing. In the illustrated embodiments, the first pump 20 and the second pump 30 are co-axially aligned and driven using a driver (e.g., a motor or engine).
More specifically, in accordance with an embodiment, the disclosed assembly 10 includes, integrated into a single housing 12, the first pump 20 (see
A drive shaft 24 is provided in the housing 12 and is configured to rotate about a drive axis A-A. The drive shaft 24 drives both the first pump 20 and the second pump 30. Both the first pump 20 and the second pump 30 have at least one gear that is configured and arranged to be rotated by the drive shaft 24. The drive shaft 24 may directly or indirectly rotate each of these gears about axis A-A. In the illustrated embodiment, as shown and described later with reference to
The housing 12 of the pump assembly 10 includes a first side 14 (see
Optionally, in an embodiment, the housing 12 may include openings or cutouts therein, such as indicated at 27 in
The housing 12 further includes a top side 26 (shown on top in
The first outlet opening 66 may be an external connection point on the housing 12 to direct pressurized lubricant from the first outlet 62 of the first pump 20, outside of the housing 12, and to a system (e.g., transmission 102). In an embodiment, the first outlet opening 66 may be provided on a plane that is parallel to the drive axis A-A of the drive shaft 24. Lubricant may be directed out the housing 12 through the first outlet opening 66 in a generally perpendicular manner relative to the drive axis A-A. In one embodiment, the first outlet opening 66 may be provided on the top side 26 of the housing 12. As shown in
Also, in one embodiment, the second pump 30 includes a second inlet 68 (see
A second inlet opening 72 (see
The second outlet opening 74 may be an external connection point on the housing 12 to direct pressurized lubricant from the second outlet 70 of the second pump 30, outside of the housing 12, and to a system (e.g., transmission 102). In an embodiment, the second outlet opening 74 may be provided on a plane that is parallel to the drive axis A-A of the drive shaft 24. Lubricant may be directed out the housing 12 through the second outlet opening 74 in a generally perpendicular manner relative to the drive axis A-A. In one embodiment, the second outlet opening 74 may be provided on the top side 26 of the housing 12. As shown in
In an embodiment, the first outlet opening 66 and the second inlet opening 72 may be both provided on a plane that is parallel to the drive axis A-A of the drive shaft 24. In an embodiment, the first outlet opening 66 and the second inlet opening 72 may be provided on the same side of the housing 12. In one embodiment, the first outlet opening 66 and the second inlet opening 72 may be provided on the top side 26 of the housing 12. In yet another embodiment, the second outlet opening 74 may be provided on the same side of the housing 12 as the first outlet opening 66 and the second inlet opening 72. That is, in accordance with an embodiment, such as shown in the Figures, the openings 66, 72, and 74 may be provided on the top side 26 of the pump assembly 10.
One or more seals 73 may be provided around or near the openings 66, 72, 74 to assist in sealing and securement. In an embodiment, such as shown in
The pump assembly 10 may also include in its housing 12 one or more openings therein that connect to the previously noted inlet path 65. In an embodiment, a main inlet may be provided in the housing 12 that directs input lubricant (e.g., from a source) into one or more of the pumps 20 and/or 30. That is, this main inlet may fluidly connect to first inlet 60 and/or second inlet 68. The main inlet has an inlet opening 76 provided in the housing 12, such as shown in
In an embodiment, illustrated in
Referring now more specifically to each of the pumps, in one embodiment, the first pump 20 of the pump assembly 10 may be an external gear pump comprising a gearset of two externally toothed and intermeshed gears 46, 48 provided on two parallel axes. In an embodiment, the first gear 46 is a driving gear that is driven by the drive shaft 24. The first gear 46 is configured and arranged to rotate about drive axis A-A. In one embodiment, the first gear 46 may be connected to the second pump 30 via drive shaft 24 and configured to rotate with the drive shaft 24. In another embodiment, the first gear 46 may be provided on its own shaft 44 that is connected to drive shaft 24 (with or without coupling 25) (further described below). In an embodiment, the second gear 48 a driven gear coupled to a rotatable shaft 52 provided on a driven axis B-B (see
In one embodiment, the second pump 30 is a gerotor pump comprising an inner rotor 56 that acts as a driving gear and that is rotated relative to an outer rotor 58. The inner rotor 56 is fixedly secured to the shaft 24 (or shaft 42) for rotation about axis A-A with the drive shaft 24. The outer rotor 58 may be rotatably received in a part of the housing 12 (specifically, common wall 80, as described below), according to one embodiment. In another embodiment, the outer rotor 58 is fixed within the common wall 80. The inner rotor 56 meshes with the outer rotor 58 using teeth provided on each gear (e.g., inner rotor 56 has male teeth or external teeth provided along an outer periphery thereof, while outer rotor 58 has female receiving portions or internal teeth in an inner periphery thereof, for receipt of the male teeth of the inner rotor 56). The outer rotor 58 has greater number of teeth or portions than the inner rotor 56. The axis of the inner rotor 56 is offset from the axis of the outer rotor 58. In one embodiment, both rotors may rotate on their respective axes. Alternatively, in another embodiment, the inner rotor 56 rotates relative to the outer rotor 58. As is understood by one of ordinary skill in the art, in accordance with one embodiment, rotation of the inner rotor 56 also rotates the outer rotor 58 via their intermeshed teeth to pressurize the input fluid received in areas between the complimentary parts for output from the pump assembly 10, and thus such details are not described here. The offset of their axes creates a changing-volume space between them. During a rotation cycle, fluid may enter a suction side of the gerotor, get pressurized due to the changing-volume space, and the pressurized fluid is discharged at a discharge port of the gerotor. The drive shaft 24 may be configured to drive the inner rotor 56, for example. In an embodiment, such as shown in
As illustrated and described herein, the housing 12 is designed such that it provides two internal chambers therein; i.e., one internal chamber for the first (high pressure, external gear) pump 20, and one internal chamber for the second (low pressure, gerotor) pump 30. Each of these internal chambers receive and pressurize lubricant therein using respective pump parts. In particular, housing 12 includes a wall 80 that is common—also referred to as a “common wall” 80 in this disclosure—to both the first pump 20 and the second pump 30 of the pump assembly 10, that forms part of each internal chamber. The common wall 80 may be positioned in a relatively radial direction (relative to the drive axis A-A) within the pump assembly 10. The first pump 20 is provided on a first radial side 82 of the common wall 80 and the second pump 30 is provided on a second radial side 84 of the common wall 80 that is opposite to the first side. As seen in
In an embodiment, the common wall 80 forms at least part of each of the internal chambers provided in the pump assembly 10, and the covers—either cover plate 16 or cover plate 36—form the other part of each of the internal chambers. For example, the common wall 80 may be a substantially flat wall that extends between the parts (e.g., gears) of the pumps 20, 30, in accordance with one embodiment. That is, each of the first and second sides of the wall 80 may be substantially flat. In this disclosure, substantially flat refers to a side of the common wall that may be positioned flush with another portion (e.g., cover) of the pump assembly 10, but that does not include pockets or chambers for receipt of pump parts therein. Such a substantially flat wall may include channels, paths, or routes that are drilled along a portion of the wall, however. In such an embodiment, the covers 16 and 36 may include pockets or openings on their inside radial walls that are sized to accommodate the gears of the pumps 20, 30 therein. When the covers 16, 36 are attached to the common wall 80, the inner radial walls of each of the covers 16, 36 may form a peripheral wall that extends around and surrounds each internal chamber (and gears of the pumps 20, 30) peripherally.
In another embodiment, the common wall 80 defines the pressurizing internal chambers in each of the pumps 20, 30, in which at least the drive gears 46, 56 are received. In the illustrated embodiment, for example, as shown in
Accordingly, the walls of the pockets 86, 54 may define axial sides of the internal chamber and include a peripheral wall 23 that extends around the gears peripherally to form the internal chambers. The covers 16, 36 may be attached to the common wall 80 to help enclose the internal chambers along with the common wall 80. The cover 36 is not shown in
The cover 16 may also contain, in one embodiment, one or more grooves 53A, 53B (see
Alternatively, in another embodiment such as shown in
In one embodiment, first pocket 86 may be formed in the first side 82 of the common wall 80 to accept drive gear 46 and its shaft (drive shaft 24 and/or shaft 44) and a third pocket is also formed in the first side 82 of the wall 80. The third pocket may be a separate pocket that is provided to contain the second/driven gear 48 of the first pump, and its rotating/driven shaft 52, therein. In accordance with yet another embodiment, a secondary pocket may be contained in either the first pocket 86 (when formed to contain a length of the intermeshed gears) or the third pocket for receiving an end of the driven shaft 52 of the external gear pump 20.
In yet another embodiment, the common wall 80 may have one side that is substantially flat and an opposite side with one or more pockets therein. The flat side of the common wall 80 may be connected to a cover plate that has one or more pockets therein for receipt of at least one of the gears for one of the pumps, such that when the cover is connected with the flat side of the common wall 80, the internal chamber is formed therein. On the opposite side of the common wall, the one or more pockets may be configured to receive one or more gears of the other of the pumps, and the cover plate may be attached thereto to form the additional internal chamber of the pump assembly 10.
The common wall 80 and/or housing 12 may be formed from any number of materials and manufactured in a number of ways. In one embodiment, the common wall 80 is molded, e.g., injection molded. In another embodiment, the common wall 80 may be formed via a molding process that further includes machining and/or drilling processes. For example, the pockets 54, 86 or rotor chambers may be machined into the common wall 80. In one embodiment, the common wall 80 may be formed via a casting process (die casting), powder metal forming, forging, stamping, or any other desired manufacturing technique. Other parts of the housing 12 may be formed by similar techniques, i.e., stamping, casting, powdered metal forming, molding, etc. In accordance with embodiments, the housing 12 and its common wall 80 may be formed using a casting technique. In accordance with embodiments the housing 12 and wall 80 may be formed from die cast aluminum or cast iron. In accordance with an embodiment, common wall 80 and the walls forming the pockets may be a single, unitary and continuous part, i.e., integral.
The drive shaft 24 extends through the wall 80 and connects to each of the driving gears 56, 46 contained in the first pocket 86 and the second pocket 54, respectively. In the illustrated embodiment, the driving gear of the external gear pump 20 is gear 46, which is driven by the drive shaft 24 connected to the second pump 30, and the driven gear is gear 48, which is coupled to rotatable shaft 52.
In an embodiment, one or more spacers 50, pressure compensation plates, or collars may be provided adjacent to the first and second gears 46, 48 of the first pump 20 to substantially prevent sliding (axial) movement of the gears 46, 48 from the wall 80. For example, the gears 46, 48 may be placed such that one side is substantially flush with first side 82 of common wall 80. Spacer(s) 50, plate(s), or collar(s) may be placed on a side opposite to the first side 82 of the common wall 80, and fitted on the shafts 44, 52 between the gears 56, 58 and the inner radial side of cover 16. As shown in the exploded view of
As previously noted, the drive shaft 24 that drives both the first pump 20 and the second pump 30 extends through the housing 12, as shown in
In one embodiment, the drive shaft 24 is a single, common drive shaft for both pumps 20, 30 that is formed as a singular shaft (or tube) and is designed to extend through the housing 12 and into at least portion of the pumps 20, 30 for driving them as it rotates about drive axis A-A. That is, the same shaft may directly drive first pump 20 and second pump 30. The receiving opening 88 may have a substantially consistent diameter along its axial length from one end (e.g., at second pocket 54) to the other (e.g., at first pocket 86).
In another embodiment, such as shown in
The drive shaft 24 is driven by a single input device or driver, which may be mechanical, electric, or electro-mechanical—e.g., an electric motor 90, such as shown in
More specifically, the connector portion 22 is provided on the second side 18 of the pump assembly 10 for connecting an input device or a driver (e.g., such a motor 90 shown in
In an embodiment, the casing 91 includes a sleeve 95 (see
The electric motor 90 may include a rotor 96 and a stator 98 (see
In this illustrated embodiment, the underside or inner radial side (pump facing side) of the cover plate 16 may include receiving openings 17 therein (see
First pump 20B in the illustrative embodiment of
The second pump 30B has a second inlet 68 (see
In accordance with an embodiment, the first inlet opening 64A is provided on a plane that is parallel to the drive axis A-A of the drive shaft 24. In accordance with an embodiment, the second outlet opening 74 is provided on a plane that is parallel to the drive axis A-A of the drive shaft 24.
In an embodiment, illustrated in the cross sectional view of
As mentioned above, in an embodiment, the second or main inlet opening 72, such as shown in
The housing 12 further includes a common wall 80 to both the first pump 20B and the second pump 30B, which is shown in
In an embodiment, the common wall 80 (see
Accordingly, the walls of the pockets 86, 54 may define axial sides of the internal chamber and include a peripheral wall that extends around the rotors/gears peripherally to form the internal chambers. The covers 16, 36 may be attached to the common wall 80 and/or housing 12 to help enclose the internal chambers along with the common wall 80. The cover 36 is not shown in
One or more seals 43 may be provided between the common wall 80 and covers 16, 36, for example. In an embodiment, a single seal 43 is provided around any openings or connection points therebetween in cover 16, such as shown in
The underside or inner radial side (pump facing side) of the cover plate 16 of the first pump 20B may include a receiving opening 17 therein (see
Referring now more specifically to each of the pumps, in accordance with an embodiment, the first pump 20B of the pump assembly 10B may be an epitrochoidal vacuum pump, designed to produce epitrochoidal-like rotation of its rotor 48A within the pocket 86 and housing 12. An epitrochoid is defined as a geometric curve or plane curve that is generated by tracing motion of a fixed point on the radius (or extended radius) of a circle as it rolls on the outside/external portion of a fixed, base circle. As understood by one of ordinary skill in the art, the shape of the inner envelope of the epitrochoid (which is the basis for the shape of the housing in which the rotor rotates) determines or aids in generating the shape of the rotor (i.e., the shape of the outer edges or lobes of the rotor). In this exemplary embodiment, for illustrative purposes and without intending to be limiting, a two lobed rotor 48A is shown. Generally, such a design improves upon such principles of a Wankel engine within a vacuum pump. In accordance with an embodiment, the first pump 20 may be or include features of the epitrochoidal pump as disclosed in U.S. patent application Ser. No. 15/946,944, filed Apr. 6, 2018, which is hereby incorporated by reference in its entirety. Below some of the features of such an epitrochoidal pump are described.
Generally, in an embodiment, the first side of the wall or pocket 86 of the epitrochoidal first pump 20B defines and is part of an internal space having an epitrochoidal shape. The rotor 48A of the epitrochoidal vacuum pump is rotatably received within the internal space or pocket 86. The rotor 48A is shaped with a number of edges that conjugate with the epitrochoidal shape of the internal space and has an internally toothed guide gear portion 49 (see
In the illustrated embodiment, for example, the first pump 20B of pump assembly 10B utilizes a two lobed rotor 48A, one inlet 60A, and at least one outlet 62A provided in a housing 12. For illustrative purposes only, the vacuum/first pump 20B is illustrated with two outlet openings 66A, that connect to passageways within the pump assembly, that form a single outlet 62A of the pump 20B. The openings 66A may be positioned adjacent or next to each other to provide another channel and larger area for expulsion of air, effectively increasing the cross-sectional area of the outlet port. This may also assist in reducing resistance(s) during expulsion, for example. Reed valves 61A (see
Pocket 86 acts as a single epitrochoidal working chamber and has a chamber volume. For each rotor revolution, each chamber fulfills two evacuation cycles. Accordingly, the total evacuation capacity per pump shaft rotation in the disclosed vacuum pump 10A is defined as: single chamber volume×1 (since there is one chamber)×2 (evacuation cycles per rotor revolution)/2 (rotor speed reduction to shaft speed); therefore, the total evacuated capacity is 1*single chamber volume. The surrounding wall of the pocket 86 defines an internal space which is an epitrochoidally generated shape (not circular or substantially circular) and is flanked by cover 16 and common wall 80. The rotor 48A is rotatably received within the internal space of the chamber or pocket 86. As is known in the art, the chamber or pocket 86 is a single working chamber that is varied in size by the rotor 48A as it rotates and orbitally revolves therein along the surrounding wall. During rotation, each side surface of the rotor 48A is brought closer to and then away from the wall of the pocket 86, without fully contacting the wall (e.g., due to manufacturing clearances). Corners or apices of the rotor 48A are guided along the wall in a sliding contact manner (e.g., via seals 75) during rotation of the rotor 48A.
The body of the rotor 48A may have a substantially ovular shape, with two sides having convex, bow-shaped flanks (see, e.g.,
The drive shaft 24 (44) is designed to extend through the rotor 48A towards cover 16. An end of the drive shaft is received within a central hole of the guide sprocket 46A and secured from rotating therein by a bushing, for example. An end of the drive shaft may be placed into the receiving opening 17. To implement eccentric movement of the rotor 48A about axis A-A, an eccentric rotation bearing 71 is provided (see
The aforementioned inlet 60A may thus be a vacuum inlet for inputting air into the housing. The vacuum inlet 60A includes an input channel or passageway that winds within the housing and receives (pulls via vacuum) air through. Air is communicated and drawn through the passageway and into at least one radial inlet port (not shown) provided in the surrounding wall of the pocket 86. Accordingly, the inlet port 64A fluidly connects to the inside of the chamber or pocket 86. Inlet 60A and its port 64A selectively draws and delivers air under negative pressure (vacuum), dependent upon the position of the rotor 48B.
In one embodiment, the second pump 30B is a vane pump comprising an inner rotor 56A and a control slide 116 (see
The rotor 56A of the second pump 30B is provided in the rotor receiving space 118, as shown in
As generally understood in the art, movement of the control slide 116 in the displacement increasing direction increases eccentricity between the rotor 56A and the control slide 116 for increasing a pressure differential between the inlet 68 and outlet 70. Conversely, movement of control slide 116 in the opposite displacement decreasing direction decreases that eccentricity for decreasing the pressure differential. The principle of operation creating the pressure differential between the low pressure side of the rotor receiving space 118 and the high pressure side thereof based on the change in volume of the pockets between the individual vanes as regulated by the eccentricity between the control slide 116 and the rotor 56A is well-known and need not be described in detail.
The rotor 56A may be powered in any manner. For example, in engine applications, the rotor 56A is often coupled to a gear or pulley driven by a belt or chain, or may be directly driven by another element of the drive train. As another example, the pump 30B may be driven by an electric motor (particularly in electrically powered vehicles) or have two input connections so as to be driven by both an engine driven element and/or an electric motor (particularly in hybrid vehicles). The manner in which the rotor 56A is driven is not limiting and may occur in any manner.
A resilient structure 124 is positioned between the housing 12 or pocket 54 and the control slide 116 to bias the control slide 116 in the displacement increasing direction. In the illustrated embodiment, the resilient structure 124 is a compression spring, but it may have any structure or configuration. The control slide 116 includes a radial projection 126 (or radially extending bearing structure) opposite the pivotal connection, e.g., pin 122, of the control slide 116 to the housing 12. The radial projection 126 has a bearing surface 128 that is engaged by the resilient structure 124. In the illustrated embodiment, one end of the spring/structure 124 engages that surface 128, and an opposite end thereof engages against an opposing surface provided in the pocket 54 or housing 12. The spring 124, as illustrated is, held in compression between those surfaces thus applying a reaction force biasing the control slide 116 in the displacement increasing direction.
The control slide 116 may have one or more seals 132 which define a control chamber 130 between the control slide 116 and the pocket 54/housing 12. The control chamber 130 is communicated with a source of the pressurized lubricant to move the control slide 116 in the displacement decreasing direction. In the illustrated embodiment, lubricant is fed into the control chamber 130 via inlet path 65 and a pocket/chamber inlet port 65A. The inlet and outlet 30, 40 are disposed on opposing radial sides of the rotational axis of the rotor 65A. The housing 12 has at least one inlet port 65A for intaking fluid to be pumped from inlet 65, and at least one outlet port 70A for discharging the fluid to outlet 70. The inlet port 65A and outlet port 70A each may have a crescent shape, and may be formed through the same wall located on one axial side or both axial sides of the housing (with regard to the rotational axis of the rotor). The inlet and outlet ports 65A, 70A may be disposed on opposing radial sides of the rotational axis of the rotor 16. These structures are conventional, and need not be described in detail. The shape of the inlet and/or outlet is not intended to be limiting. Other configurations may be used, such as differently shaped or numbered ports, etc. Further, it should be understood that more than one inlet or outlet may be provided (e.g., via multiple ports). The chamber inlet port 65A may be communicated (directly or indirectly) to chamber outlet port 70A, through outlet path 70B and to second outlet 70 of the housing 12, and thus the source of pressurized lubricant for the control chamber 130 is the lubricant discharged from the outlet 70. This is a known feedback approach wherein the pressure from the outlet 70 is used to help regulate the pump's displacement and pressure. As the pressure fed back from the outlet 70 increases, that will result in a pressure increase in the control chamber 130, which in turn moves the control slide 116 in the displacement decreasing direction against the bias of the resilient structure 124 (and that in turn will also decrease the pressure differential generated by vanes 120 and thus the pressure of the lubricant discharged from the outlet 70). Conversely, as the pressure fed back from the outlet 70 decreases, that will result in a pressure decrease in the control chamber 130, which in turn allows the resilient structure to move the control slide 116 in the displacement increasing direction (and that in turn will also increase the pressure differential generated by the rotor 56A and thus the pressure of the lubricant discharged from the outlet 70). This technique may be used to maintain a pump's output pressure and/or volumetric displacement at or near equilibrium levels.
The second pump 30B may have multiple control chambers for providing different levels of control over the operation of the pump assembly 10B, in accordance with embodiments. In other embodiments, the pump 30B may have only one control chamber.
The second pump 30B may also include several safety features associated therewith. For example, one or more fail-safe pressure relief valves 140 (e.g., ball valves, check valves, panic valves) may be provided in the housing 12 (see
Also, while the above exemplary embodiments with respect to
As such, the exemplary embodiment as shown in
The operation of the pump assembly 10 and/or 10A is further described with reference to
Even though the second pump 30 is configured to continuously pump lubricant to the transmission, the first (high pressure, external gear) pump 20 is not stationary. In accordance with an embodiment, the first pump 20 is also configured to rotate with operation of the motor 90, due to the connecting drive shaft 24 between the two pumps 20 and 30. However, output from the first pump 20 is generally limited in operating conditions, e.g., at approximately 3.0 bar. In some embodiments, e.g., when higher pressurized lubricant is needed by the transmission, such as when lubricant is needed in by a clutch 108 in order for a shift operation to occur, there are instances wherein the first pump 20 is selectively activated. That is, first pump 20 may be activated to output higher pressurized lubricant to the transmission. In accordance with an embodiment, the first pump 20 is configured for use to output lubricant to the clutch 108/transmission when a desired operational pressure of the lubricant is greater than approximately 20 bar. In one embodiment, the first pump 20 is configured to operate when the desired pressure for the outside system/transmission 102 is in a range of approximately 20 bar to approximately 60 bar (both inclusive).
In accordance with an embodiment, control valve 114, shown schematically in
The controller 104 is further configured to control the selective activation of the valve 114 and thus use of the output from the first pump 20.
The first epitrochoidal pump 20B may be used provide a vacuum, i.e., negative pressure or air, to any number of systems in a vehicle, e.g., a brake booster system, pneumatic actuators, and/or valves. The second vane pump 30B may be used as an oil pump to supply pressurized lubricant to another system, e.g., to act as a booster for a circuit to an engine or transmission, to provide lubricant and/or cooling to a gearbox, to assist in clutch operation, and/or another smaller pump within a vehicle.
Accordingly, the pump assemblies 10 and 10A and 10B as disclosed herein provides several features and improvements, including that both pumps (20, 30) provided in the assemblies 10 and 10A and 10B are integrated and contained in one housing and share a common wall 80 in that housing, thereby allowing for a more compact configuration and construction. As such, a larger space needed for mounting the disclosed pump assembly is not necessary. Further, fabrication and machining costs for forming the housing 12 are reduced. Additionally, both pumps (20, 30) are driven via the same shaft 24 (whether of singular or connected construction) in the housing 12.
When used in a system with a control valve, the output from the first pump may be limited. As such, the pump assembly 10 and/or 10A and/or 10B may operate under a range of operating conditions or stages, including selective use of a high pressure/first pump when required.
While the principles of the disclosure have been made clear in the illustrative embodiments set forth above, it will be apparent to those skilled in the art that various modifications may be made to the structure, arrangement, proportion, elements, materials, and components used in the practice of the disclosure.
It will thus be seen that the features of this disclosure have been fully and effectively accomplished. It will be realized, however, that the foregoing preferred specific embodiments have been shown and described for the purpose of illustrating the functional and structural principles of this disclosure and are subject to change without departure from such principles. Therefore, this disclosure includes all modifications encompassed within the spirit and scope of the following claims.
Claims
1. A two-stage pump assembly comprising:
- a first pump and a second pump for pumping lubricant to a system, both the first pump and the second pump being integrated into a single housing and each configured to pressurize lubricant input into the housing;
- a drive shaft provided in the housing configured to rotate about a drive axis and drive both the first pump and the second pump, the drive shaft being driven by a single input device;
- both the first pump and the second pump comprising at least one gear configured and arranged to be rotated by the drive shaft;
- the first pump comprising a first inlet provided on the housing for receiving lubricant from a source outside the housing and a first outlet for directing lubricant that is pressurized out of the housing;
- the second pump comprising a second inlet provided on the housing for receiving lubricant from the source outside the housing and a second outlet for directing lubricant that is pressurized out of the housing, the second inlet and the second outlet being different than the first inlet and the first outlet, respectively;
- the housing further comprising a wall that is common to both the first pump and the second pump, the first pump being provided on a first side of the wall and the second pump being provided on a second side of the wall that is opposite to the first side, and wherein the drive shaft extends through the wall and connects to each of the at least one gears of both the first pump and the second pump.
2. The pump assembly of claim 1, wherein the wall includes a first pocket on the first side thereof containing the at least one gear of the first pump therein and a second pocket on a second side thereof, the second pocket containing the at least one gear of the second pump therein, and wherein the drive shaft extends through the wall and connects to each of the at least one gears contained in the first pocket and the second pocket.
3. The pump assembly of claim 1, wherein the single input device for driving the drive shaft of the pump assembly is an engine, a transmission, or an electric motor.
4. The pump assembly of claim 1, wherein the first pump is an external gear pump comprising two gears provided on two parallel axes, a first gear of the two gears being a driving gear that is driven by the drive shaft connected to the second pump, and a second gear of the two gears being a driven gear coupled to a rotatable shaft.
5. The pump assembly of claim 2, wherein the wall further comprises a third pocket therein, the third pocket being provided on the first side of the wall, wherein the first pump is an external gear pump comprising first and second gears provided on two parallel axes, and wherein the second gear of the first pump is contained in the third pocket.
6. The pump assembly of claim 4, wherein the second pump is a gerotor pump comprising an inner rotor that acts as a driving gear and that is rotated relative to an outer rotor, and wherein the outer rotor of the second pump is provided on the second side of the wall.
7. The pump assembly of claim 1, wherein the drive shaft is a single, common drive shaft.
8. The pump assembly of claim 1, wherein the drive shaft comprises a first drive shaft and a second drive shaft co-axially connected to one another for rotating together about the drive axis.
9. The pump assembly of claim 8, wherein the first drive shaft and the second drive shaft are connected via a coupling.
10. The pump assembly of claim 1, further comprising a first cover plate connected to the housing and covering at least the at least one gear of the first pump and a second cover plate connected to the housing and covering at least the at least one gear of the second pump.
11. The pump assembly of claim 10, Wherein the first cover plate of the first pump comprises a floating cover plate.
12. The pump assembly of claim 10, wherein the first cover plate of the first pump comprises a fixed cover plate.
13. The pump assembly of claim 10, wherein the first inlet of the first pump comprises a first inlet opening provided in the first cover plate, the first inlet opening receiving the lubricant from the source outside the housing, and wherein the first inlet opening is provided on a plane that is perpendicular to the drive axis of the drive shaft.
14. The pump assembly of claim 13, wherein the first outlet comprises a first outlet opening, wherein the second inlet comprises a second inlet opening, and wherein the first outlet opening and the second inlet opening are provided on the same side of the housing.
15. The pump assembly of claim 14, wherein the first outlet opening and the second inlet opening are provided on a plane that is parallel to the drive axis of the drive shaft.
16. The pump assembly of claim 14, wherein the second outlet comprises a second outlet opening, and wherein the second outlet opening is provided on the same side of the housing as the first outlet opening and the second inlet opening.
17. The pump assembly of claim 16, wherein the second outlet opening is provided on a plane that is parallel to the drive axis of the drive shaft.
18. The pump assembly of claim 16, wherein the second pump further comprises a third inlet, the third inlet comprising a third inlet opening, and wherein the third inlet opening is positioned on another side of the housing that is traverse to the side of the housing containing the first outlet opening, the second inlet opening, and the second outlet opening.
19. The pump assembly of claim 18, wherein the third inlet opening is provided on a plane that is perpendicular to the drive axis of the drive shaft.
20. The pump assembly of claim 18, wherein the first inlet opening and the third inlet opening are provided on the same side of the housing.
21. A system comprising the two stage pump assembly of claim 1 and a transmission, wherein the second pump is configured to continuously pump the lubricant to the transmission, and wherein the transmission comprises a clutch system that selectively receiving lubricant pumped from the first pump, the system further comprising a control valve for limiting the lubricant that is output from the first pump to the clutch system of the transmission.
22. A system comprising the two stage pump assembly of claim 1 and a driver connected to the pump assembly, wherein the driver is configured to rotate the drive shaft of the pump assembly for pumping the lubricant to the driver.
23. A pump assembly comprising:
- a first pump for pumping air and a second pump for pumping lubricant to a system, both the first pump and the second pump being integrated into a single housing;
- a drive shaft provided in the housing configured to rotate about a drive axis and drive both the first pump and the second pump, the drive shaft being driven by a single input device;
- both the first pump and the second pump comprising a rotor configured and arranged to be rotated by the drive shaft;
- the first pump comprising a first inlet provided on the housing for receiving air from outside the housing and a first outlet for directing air that is pressurized out of the housing;
- the second pump comprising a second inlet provided on the housing for receiving lubricant from a source outside the housing and a second outlet for directing lubricant that is pressurized out of the housing, the second inlet and the second outlet being different than the first inlet and the first outlet, respectively;
- the housing further comprising a wall that is common to both the first pump and the second pump, the first pump being provided on a first side of the wall and the second pump being provided on a second side of the wall that is opposite to the first side, and wherein the drive shaft extends through the wall and connects to each of the rotors of both the first pump and the second pump.
24. The pump assembly of claim 23, wherein the wall includes a first pocket on the first side thereof containing the rotor of the first pump therein and a second pocket on a second side thereof, the second pocket containing the rotor of the second pump therein, and wherein the drive shaft extends through the wall and connects to each of the rotors contained in the first pocket and the second pocket.
25. The pump assembly of claim 23, wherein the single input device for driving the drive shaft of the pump assembly is an engine, a transmission, or an electric motor.
26. The pump assembly of claim 3, wherein the first pump is an epitrochoidal vacuum pump, wherein the first side of the wall defines and is part of an internal space having an epitrochoidal shape, wherein the rotor of the epitrochoidal vacuum pump is rotatably received within the internal space, the rotor being shaped with a number of edges that conjugate with the epitrochoidal shape of the internal space and comprising an internally toothed guide gear; the drive shaft being configured to rotate the rotor eccentrically within the internal space; and wherein the epitrochoidal vacuum pump comprises an externally toothed guide sprocket for meshing with and guiding movement of the guide gear of the rotor as it is driven by the drive shaft.
27. The pump assembly of claim 26, wherein the second pump is a vane pump comprising a control slide having a rotor receiving space communicated to the first inlet and the first outlet, the rotor of the second pump being provided in the rotor receiving space, the rotor comprising a plurality of vanes, the vanes being movable within the rotor receiving space, and the rotor being rotatable in the rotor receiving space to draw lubricant under negative pressure into the rotor receiving space via the second inlet for pressurization and discharge pressurized lubricant from the rotor receiving space via the second outlet under positive pressure.
28. The pump assembly of claim 23, wherein the drive shaft is a single, common drive shaft.
29. The pump assembly of claim 23, wherein the drive shaft comprises a first drive shaft and a second drive shaft co-axially connected to one another for rotating together about the drive axis.
30. The pump assembly of claim 23, wherein the first inlet of the first pump comprises a first inlet opening for receiving the air from outside the housing, and wherein the first inlet opening is provided on a plane that is perpendicular to the drive axis of the drive shaft.
31. The pump assembly of claim 30, wherein the rotor of the first pump is provided on a first side of a plane parallel to the common wall and wherein the first inlet opening is provided on a second side of the plane that is parallel to the common wall.
32. The pump assembly of claim 30, wherein the first outlet comprises a first outlet opening, wherein the second inlet comprises a second inlet opening, and wherein the first outlet opening and the second inlet opening are provided on the same side of the housing.
33. The pump assembly of claim 30, wherein the second outlet comprises a second outlet opening, and wherein the second outlet opening is provided on the same side of the housing as the first inlet opening.
34. The pump assembly of claim 33, wherein the second outlet opening is provided on a plane that is parallel to the drive axis of the drive shaft.
Type: Application
Filed: Dec 20, 2019
Publication Date: Jul 2, 2020
Inventors: Ralph Valkenberg (Stolberg), Luke Bouwmeester (Toronto)
Application Number: 16/722,543