초록 ▼

A variable capacity gerotor pump includes an inner rotor that is axially displaceable with respect to the outer rotor to vary the volumetric capacity of the pump. An active piston abuts the lower surface of the inner rotor and can ride inside the outer rotor, as the inner rotor is axially displaced,

A variable capacity gerotor pump includes an inner rotor that is axially displaceable with respect to the outer rotor to vary the volumetric capacity of the pump. An active piston abuts the lower surface of the inner rotor and can ride inside the outer rotor, as the inner rotor is axially displaced, to provide the necessary scaling of the lower surface of the inner rotor with respect to the outer rotor. A passive piston, against which a return spring acts, abuts the upper surface of the inner rotor to provide the necessary sealing of the upper surface of the inner rotor with respect to the outer rotor. In an embodiment, a control chamber, supplied with pressurized working fluid, generates a force acting against the force of the return spring to move the inner rotor to reduce the volumetric capacity of the pump. In another embodiment, a control mechanism, such as an electric solenoid or mechanical mechanism, acts on the control piston against the force of the return spring.

대표청구항 ▼

We claim: 1. A variable capacity gerotor pump, comprising: a pump housing defining a pump chamber, a pump inlet and a pump outlet; an inner rotor; an outer rotor rotatably located within the pump body, the inner rotor located within the outer rotor and the lobes of the inner rotor and outer rotor e

We claim: 1. A variable capacity gerotor pump, comprising: a pump housing defining a pump chamber, a pump inlet and a pump outlet; an inner rotor; an outer rotor rotatably located within the pump body, the inner rotor located within the outer rotor and the lobes of the inner rotor and outer rotor engaging, the outer rotor rotates about an axis which is eccentric from an axis of rotation of said inner rotor; a drive shaft engaging the inner rotor to rotate the inner rotor and the outer rotor when the drive shaft is rotated, the inner rotor being axially displaceable along the drive shaft to alter the volumetric capacity of the pump; an active piston including non-rotating sealing surfaces acting between the inner rotor and the outer rotor and the pump housing to create a high pressure region at the pump outlet and a low pressure region at the pump inlet when the drive shaft is rotated, the active piston abutting a surface of the inner rotor and including a substantially cylindrical surface having a radial center offset from the axis of rotation of the outer rotor to provide a seal between the surface of the inner rotor and the outer rotor, when the inner rotor is axially displaced, the cylindrical surface being in contact with two lobes of the outer rotor, and the active piston including a sealing land engaging another lobe of the outer rotor at a position substantially diametrically opposed to the two lobes; and a return spring biasing the inner rotor to a position of axial alignment with the outer rotor. 2. The variable capacity gerotor pump of claim 1 wherein the pump further includes a control chamber formed between the active piston and the drive shaft, the control chamber receiving pressurized working fluid from the pump outlet to create a force acting against the bias of the return spring to axially displace the inner rotor. 3. The variable capacity gerotor pump of claim 1 wherein the pump further includes a plurality of control chambers, each formed between the active piston and the drive shaft, each control chamber receiving pressurized working fluid from the pump outlet to create a force acting against the bias of the return spring to axially displace the inner rotor. 4. The variable capacity gerotor pump of claim 1 wherein the pump further includes a control mechanism to create a force acting on the active piston against the bias of the return spring to axially displace the inner rotor. 5. The variable capacity gerotor pump of claim 4 wherein the control mechanism is an electric solenoid. 6. The variable capacity gerotor pump of claim 1 wherein the inner and outer rotors are a trochoidal design. 7. The variable capacity gerotor pump of claim 1 wherein the inner and outer rotors are a cycloidal design. 8. The variable capacity gerotor pump of claim 1 further including a passive piston having diametrically opposed lands engaging the inner rotor. 9. The variable capacity gerotor pump of claim 1 wherein the inner and outer rotors are a duocentric design. 10. The variable capacity gerotor pump of claim 1 wherein the inner and outer rotors are a parachoid design. 11. The variable capacity gerotor pump of claim 1 wherein the lobes of the inner rotor and outer rotor engage without a dead volume therebetween. 12. A variable capacity gerotor pump, comprising: a pump housing defining a pump chamber, a pump inlet and a pump outlet; an inner rotor; an outer rotor rotatably located within the pump housing, the inner rotor located within the outer rotor and being rotatable about an axis which is eccentric from an axis of rotation of the outer rotor; a drive shaft fixed for rotation with the inner rotor, the inner rotor being axially displaceable along the drive shaft to alter the volumetric capacity of the pump; an axially moveable, non-rotatable active piston being sealingly engageable with the inner rotor and a lobe of the outer rotor, the active piston including a convex sealing land engageable with another lobe of the outer rotor, wherein multiple additional lobes of the outer rotor are spaced apart from the active piston when the sealing land engages the another outer rotor lobe; and a return spring biasing the inner rotor to a position of axial alignment with the outer rotor. 13. The variable capacity gerotor pump of claim 12 wherein the active piston includes a substantially cylindrical surface having a radial center offset from an axis of rotation of the outer rotor that engages two lobes of the outer rotor, the convex sealing land having a radial center coaxially aligned with the outer rotor axis. 14. The variable capacity gerotor pump of claim 13 wherein the pump further includes a control chamber formed between the active piston and the drive shaft, the control chamber receiving pressurized working fluid from the pump outlet to create a force acting against the bias of the return spring to axially displace the inner rotor. 15. The variable capacity gerotor pump of claim 13 wherein the pump further includes a control mechanism to create a force acting on the active piston against the bias of the return spring to axially displace the inner rotor. 16. A variable capacity gerotor pump, comprising: a pump including a housing defining a pump chamber, a pump inlet and a pump outlet; an inner rotor; an outer rotor rotatably positioned within the pump housing, the inner rotor being positioned within the outer rotor, and lobes of the inner rotor engaging lobes of the outer rotor, the outer rotor rotating about an axis offset from an axis of rotation of the inner rotor; a drive shaft drivingly coupled to the inner rotor, the inner rotor being axially displaceable along the drive shaft to alter the volumetric capacity of the pump; an axially moveable active piston including sealing surfaces being engageable with the inner rotor, the outer rotor and the pump housing; a passive piston having diametrically opposed lands engaging the inner rotor and cylindrical surfaces of the housing to define a high pressure region at the pump outlet and a low pressure region at the pump inlet when the drive shaft is rotated; and a return spring biasing the inner rotor to a position of axial alignment with the outer rotor. 17. The variable capacity gerotor pump of claim 16 further including a pin coupled to the housing and positioned within a slot of the active piston to restrict rotation of the active piston. 18. The variable capacity gerotor pump of claim 17 further including another pin coupled to the housing and positioned within a slot of the passive piston to restrict rotation of the passive piston. 19. The variable capacity gerotor pump of claim 16 further including a drive pin captured within a pocket formed in the drive shaft, the drive pin being partially positioned within a slot of the inner rotor to transmit torque between and allow relative axial movement between the drive shaft and the inner rotor.