Hydrostatic torque converter and torque amplifier
An example includes a hydraulically controllable coupling to couple a rotating input and to an output to rotate, or to decouple the input and the output, with coupling and decoupling modes selected by switching a hydraulic device such as a vane pump between a pumping mode and a mode in which it does not pump. In an example, the system cooperates with a transmission to increase the number of possible gear ratios in some examples.
1. A system for a vehicle, the system comprising:
a hydraulic coupling comprising:
a rotor disposed for rotation about an axis;
a plurality of vanes each moveable relative to the rotor between a retracted position and an extended position where the plurality of vanes work a hydraulic fluid introduced adjacent the rotor, wherein each of the plurality of vanes has an outer tip with a recess therein;
a roller mounted at the outer tip of each of the plurality of vanes at least partially positioned within the recess; and
a ring disposed at least partially around the rotor;
an input shaft and an output shaft coupled to rotate together by the hydraulic coupling in a vane extended mode of operation, and the input shaft and output shaft are free to rotate with respect to one another in a vane retracted mode of operation; and
an accumulator configured to store pressurized fluid.
2. The system of claim 1 , wherein the hydraulic coupling is configured to retain the plurality of vanes in the retracted position within the rotor and is configured to release the plurality of vanes from the rotor to the extended position.
3. The system of claim 1 , further comprising a hydraulic pump motor coupled to the output shaft, the hydraulic pump motor including a pump motor port in fluid communication with the hydraulic coupling configured to selectively deliver an amount of fluid at a discharge pressure, the pump motor receives fluid from the hydraulic coupling to propel the output shaft in the vane extended mode of operation.
4. The system of claim 3 , wherein the hydraulic pump motor comprises a digitally controlled piston pump.
5. The system of claim 3 , wherein the pump motor is configured to operate to pump pressurized fluid generated during vehicle deceleration to the accumulator in a regenerative braking mode of operation for the vehicle.
6. The system of claim 3 , wherein the pressurized fluid stored in the accumulator is used by the pump motor to accelerate the vehicle.
7. The system of claim 3 , wherein the pump motor is configured to be stroked at least one of partially or fully when the vehicle is in a neutral condition.
8. The system of claim 3 , further comprising:
a torque producer coupled to the input shaft; and
a powertrain coupled to the output shaft, wherein the hydraulic motor pump strokes on to move the powertrain in a drive mode of operation for the vehicle.
9. The system of claim 1 , further comprising a relief valve that controls a torque output magnitude of the coupling.
10. The system of claim 1 , wherein the coupling is configured to act as a mechanical shaft to lock the input shaft to the output shaft and the pump motor strokes off when the vehicle is in a steady state driving mode of operation.
11. The system of claim 1 , wherein the motor pump is configured to boost torque on the output shaft.
12. A method comprising:
providing a hydraulic device configured as both a coupling and a vane pump, wherein the hydraulic device has a plurality of vanes that are extendable from and retractable in a rotor, and wherein a tip of each of the plurality of vanes includes a roller bearing; and
flowing a pressurized hydraulic fluid from the hydraulic device to an accumulator.
13. The method of claim 12 ; further comprising coupling a pump motor selectively with the hydraulic device.
14. The method of claim 13 , comprising flowing the pressurized hydraulic fluid from the hydraulic device to the pump motor.
15. The method of claim 13 , comprising bleeding pressure generated by the vane pump over a relief valve when the accumulator is full.
16. The method of claim 13 , comprising driving, after the regenerative braking mode, the load with the vane pump using hydraulic pressure stored in the accumulator.
17. The method of claim 12 , comprising storing the pressurized hydraulic fluid in the accumulator in a regenerative braking mode.
18. A vehicle system comprising:
a hydraulic coupling having a body and at least a first vane configured for movement relative to the body, the hydraulic coupling adapted to retain the first vane in a retracted vane mode of operation and to release the first vane in a vane extended mode of operation in which the first vane extends to meet the body to hydraulically work fluid when the first vane is moved with respect to the body;
an input shaft and an output shaft coupled to rotate together by the hydraulic coupling in the vane extended mode of operation, and the input shall and output shaft are free to rotate with respect to one another in the vane retracted mode of operation;
an accessory configured to operate as a pump in one operation mode to pump a pressurized fluid;
a torque producer coupled to the input shaft; and
an accumulator configured to store pressurized fluid.
19. The system of claim 18 , further comprising a transmission coupled to the output shaft, wherein the coupling is disposed between the torque producer and the transmission and is in fluid communication with and drives the accessory in the vane extended mode of operation.
20. The system of claim 18 , wherein the accessory comprises a motor pump.