Vane pump housing

Abstract

 A variable capacity vane pump has a housing defining a main chamber having an inlet port and an outlet port. A pump control ring (44) is moveable within the main chamber to alter the capacity of the pump. The control ring divides the main chamber into a pressurized region (45) and an unpressurized region. A vane pump rotor is rotatably mounted within the pump control ring. The vane pump rotor has a plurality of slidably mounted vanes engaging an inside surface of the pump control ring. The vane pump rotor has an axis of rotation eccentric from a centre of the pump control ring, whereby as the vane pump rotor rotates fluid is pressurized and moves from the inlet port to the outlet port. A control chamber (60,64) is provided between the pump casing and the pump control ring, and is operable to receive pressurized fluid to create a force to move the pump control ring to reduce the volumetric capacity of the pump. A return spring (56) acts between pump ring and the casing to bias the pump ring towards a position of maximum volumetric capacity. An opening (51) extends through the housing communicating with the unpressurized region, minimizes a clearance between the vane pump and engine on which the vane pump is mounted.

Description

Field of the Invention

[0001] The present invention relates to a vane pump housing. More specifically, the present invention relates to a vane pump housing in which openings are provided to enable the vane pump to be installed on an engine with a predetermined envelope of space available for the vane pump.

Background Of The Invention

[0002] Variable capacity vane pumps are well known and can include a capacity adjusting element, in the form of a pump control ring that can be moved to alter the rotor eccentricity of the pump and hence alter the volumetric capacity of the pump. If the pump is supplying a system with a substantially constant orifice size, such as an automobile engine lubrication system, changing the output volume of the pump is equivalent to changing the pressure produced by the pump.

[0003] Having the ability to alter the volumetric capacity of the pump to maintain an equilibrium pressure is important in environments such as automotive lubrication pumps, wherein the pump will be operated over a range of operating speeds. In such environments, to maintain an equilibrium pressure it is known to employ a feedback supply of the working fluid (e.g. lubricating oil) from the output of the pump to a control chamber adjacent the pump control ring, the pressure in the control chamber acting to move the control ring, typically against a biasing force from a return spring, to alter the capacity of the pump.

[0004] When the pressure at the output of the pump increases, such as when the operating speed of the pump increases, the increased pressure is applied to the control ring to overcome the bias of the return spring and to move the control ring to reduce the capacity of the pump, thus reducing the output volume and hence the pressure at the output of the pump.

[0005] Conversely, as the pressure at the output of the pump drops, such as when the operating speed of the pump decreases, the decreased pressure applied to the control chamber adjacent the control ring allows the bias of the return spring to move the control ring to increase the capacity of the pump, raising the output volume and hence pressure of the pump.

[0006] It is desirable to provide an engine with a variable vane pump to improve engine efficiency. Thus in certain current engine applications, it is desirable to re-configure an engine to utilize a variable vane pump rather than a conventional rotor pump. However, since the envelope or volume of space allocated to a conventional rotor pump is less than the required volume for a variable vane pump, the larger volume variable vane pump is unable to fit within the allocated space: A complete engine redesign, including redesigning the engine block would be required to accommodate the larger sized variable vane pump.

[0007] It is desirable to provide a variable vane pump that has a housing that can be configured to fit within the predetermined volume of space.

Summary Of The Invention

[0008] It is an object of the present invention to provide a housing for a variable vane pump that obviates or mitigates at least one disadvantage of the prior art.

[0009] According to a first aspect of the present invention, there is provided a variable capacity vane pump having a housing defining a pump chamber. A pump control ring is moveable within the pump chamber to alter the capacity of the pump. A vane pump rotor is rotatably mounted in the pump chamber. The pump control ring encloses the vane pump rotor within the pump chamber. The control pump ring is moveable within the pump chamber to alter the capacity of the pump. At least one control chamber between the housing and the pump control ring is operable to receive pressurized fluid to create a force to move the pump control ring to reduce the volumetric capacity of the pump. A return spring acts between pump ring and the housing to bias the pump ring towards a position of maximum volumetric capacity. The housing is provided with an opening to the pump chamber, which opening enables the vane pump to be mounted on the engine within the predetermined volume.

[0010] According to another aspect of the present invention, there is provided a variable capacity vane pump wherein the vane pump is oriented in an inverted condition and the housing has an opening in an upper section to accommodate vane pump being mounted on the engine within the predetermined volume.

Brief Description Of The Drawings

[0011] Preferred embodiments of the present invention will now be described, by way of example only, with reference to the attached Figures, wherein:

[0012] Figure 1 is a perspective view of a variable capacity vane pump in accordance with the present invention;

[0013] Figure 2 is a perspective view of the pump of Figure 1 with the cover and some of the pump elements removed; and

[0014] Figure 3 is a front view of a prior art pump in a conventional orientation and with the control ring position for minimum eccentricity.

Detailed Description Of The Invention

[0015] A variable capacity vane pump in accordance with an embodiment of the present invention is indicated generally at 20 in Figures 1 and 2. It is known to provide a control chamber adjacent a pump control ring and a return spring to move the pump ring of a variable capacity vane pump to establish an equilibrium output volume, and its related equilibrium pressure. Thus, the internal operation of the pump is conventional and will be described with reference to the pump 20' of Figure 3.

[0016] Referring now to Figure 3, pump 20' includes a housing or casing 22 with a front pump cover 24 and a suitable gasket. Pump 20' is mounted to an engine (not shown) or the like for which pump 20' is to supply pressurized working fluid. Pump 20' is driven via shaft 28 in a conventional manner by any suitable means, such as the engine or other mechanism to which the pump is to supply working fluid, to operate pump 20'.

[0017] Housing 22 defines a main chamber 35. Pump control ring 44 is mounted within the main chamber 35 of housing 22 via a pivot pin 52 which allows the center of pump control ring 44 to be moved.

[0018] A series of slidable pump vanes 40 rotate with rotor 32, the outer end of each vane 40 engaging the inner surface of a pump control ring 44, which forms the outer wall of pump chamber 36. Pump chamber 36 is divided into a series of working fluid chambers 48, defined by the inner surface of pump control ring 44, pump rotor 32 and vanes 40. The pump rotor 32 has an axis of rotation that is eccentric from the center of the pump control ring 44.

[0019] As pump control ring 44 pivots, the center of pump control ring 44, the volume of working fluid chambers 48 changes as the chambers 48 rotate around pump chamber 36, with their volume becoming larger at the low pressure side of pump 20' and smaller at the high pressure side of pump 20'. This change in volume of working fluid chambers 48 generates the pumping action of pump 20', drawing working fluid from an inlet port 50 and pressurizing and delivering it to an outlet port 54.

[0020] By moving pump control ring 44 about pivot pin 52 the amount of eccentricity, relative to pump rotor 32, can be changed to vary the amount by which the volume of working fluid chambers 48 change from the low pressure side of pump 20' to the high pressure side of pump 20', thus changing the volumetric capacity of the pump. A return spring 56 biases pump control ring 44 to the position, wherein the pump has a maximum eccentricity.

[0021] Preferably, pump 20' includes two control chambers 60 and 64 to control pump ring 44. Control chamber 60 is formed between pump casing 22, pump control ring 44, pivot pin 52 and a resilient seal 68, mounted on pump control ring 44 and abutting casing 22. Control chamber 60 is in direct fluid communication with pump outlet 54 such that pressurized working fluid from pump 20 which is supplied to pump outlet 54 also fills control chamber 60.

[0022] As will be apparent to those of skill in the art, control chamber 60 need not be in direct fluid communication with pump outlet 54 and can instead be supplied from any suitable source of working fluid, such as from an oil gallery in an automotive engine being supplied by pump 20'.

[0023] Pressurized working fluid in control chamber 60 acts against pump control ring 44 and, when the force on pump control ring 44 resulting from the pressure of the pressurized working is sufficient to overcome the biasing force of return spring 56, pump control ring 44 pivots about pivot pin 52, as indicated by arrow 72 in Figure 3, to reduce the eccentricity of pump 20. When the pressure of the pressurized working is not sufficient to overcome the biasing force of return spring 56, pump control ring 44 pivots about pivot pin 52, in the direction opposite to that indicated by arrow 72, to increase the eccentricity of pump 20'.

[0024] Pump 20' optionally includes a second control chamber 64, which is formed between pump casing 22, pump control ring 44, resilient seal 68 and a second resilient seal 76. Resilient seal 76 abuts the wall of pump casing 22 to separate control chamber 64 from pump inlet 50 and resilient seal 68 separates chamber 64 from chamber 60.

[0025] Control chamber 64 is supplied with pressurized working fluid through a control port 80. Control port 80 can be supplied with pressurized working fluid from any suitable source, including pump outlet 54 or a working fluid gallery in the engine or other device supplied from pump 20. A control mechanism (not shown) such as a solenoid operated valve or diverter mechanism is employed to selectively supply working fluid to chamber 64 through control port 80, as discussed below. As was the case with control chamber 60, pressurized working fluid supplied to control chamber 64 from control port 80 acts against pump control ring 44.

[0026] In the present invention, it is preferred to orient the variable vane pump in an inverted condition as illustrated in Figure 2. Elements of the vane pump have been removed for better illustration, namely seals 68 and 76 and vanes 40.

[0027] Control ring 44 will separate the main chamber 35 of the housing which outside of the periphery of the control ring 44 into a pressurized region 45 and an unpressurized region 47. The pressurized region 45 is defined by control chambers 60 and 64. The control ring 44 is sealed within the main chamber 35 to ensure that the working fluid does not substantially leak out from inside of the control ring 44 and the pressurized region 45 to the unpressurized region 47.

[0028] Housing 22 is provided with a vent opening 49, which allows air to egress and ingress as the spring operates against the pressure of the working fluid. Vent opening 49 communicates with the unpressurized region 47. The upper portion of the housing 22 is provided with a fit opening 51. Optionally, the control ring 44 can also be provided with a cut-out 53 to ensure that the control ring 44 does not interfere with the engine during operation.

[0029] As is now apparent, the upper portion of the housing 22 of the variable vane pump can be configured to include a fit opening 51 which allows the pump designer greater latitude to fit the variable vane pump 20 in the envelope determined by the engine manufacturer. The pump designer is able to reduce clearances between the variable vane pump 20 and the engine.

[0030] The above-described embodiments of the invention are intended to be examples of the present invention and alterations and modifications may be effected thereto, by those of skill in the art, without departing from the scope of the invention which is defined solely by the claims appended hereto.

Claims

1. A variable capacity vane pump (20) having

a housing (22, 24) defining a main chamber (35) having an inlet port (50) and an outlet port (54);

a pump control ring (44) which is moveable within the main chamber (35) to alter the capacity of the pump (20), said control ring (44) dividing said main chamber (35) into a pressurized region (45) and an unpressurized region (47),

a vane pump rotor (32) rotatably mounted within the pump control ring (44), said vane pump rotor (32) having a plurality of slidably mounted vanes (40) engaging an inside surface of said pump control ring (44), the vane pump rotor (32) having an axis of rotation eccentric from a centre of said pump control ring (44), the vane pump rotor (32) rotates to pressurize fluid as the fluid moves from the inlet port (50) to the outlet port (54);

a control chamber (60, 64) between the pump casing and the pump control ring defining said pressurized region (45), the control chamber (60, 64) operable to receive pressurized fluid to create a force to move the pump control ring (44) to reduce the volumetric capacity of the pump (20);

a return spring (56) acting between pump control ring (44) and the housing (22) to bias the pump control ring (44) towards a position of maximum volumetric capacity, and
characterized by

a fit opening (51) extending through said housing communicating with said unpressurized region (47).

2. A variable capacity vane pump (20) as set forth in claim 1, wherein said vane pump (20) is oriented with the unpressurized region (47) is positioned above said pressurized region (45).

3. A variable capacity vane pump (20) as set forth in any preceding claim, wherein said pump control ring (44) has a cut-out (53) adjacent said fit opening (51).

4. A variable capacity vane pump (20) as set forth in claim 3, wherein said housing (22, 24) has a vent opening (49) communicating with said unpressurized region (47).

5. A variable capacity vane pump (20) as set forth in claim 4, wherein said vane pump (20) is mounted on the underside of an engine and said opening minimizes a clearance between said vane pump (20) and said engine.

Drawing