Claims
- 1. An hydraulic drive apparatus comprising:
- (a) a supply line for receiving an hydraulic fluid;
- (b) displacement chamber means defining a plurality of displacement chambers, each connected to said supply line for progressive filling by said hydraulic fluid in response to an increase of flow rate in said supply line;
- (c) a plurality of working surfaces, each positioned within one of said displacement chambers for movement in response to said progressive filling; and
- (d) flow division means for apportioning the flow of said hydraulic fluid between said displacement chambers; said at least one of said plurality of working surfaces being coupled to a drive shaft and applying a tongue to drive said shaft for driving a component.
- 2. A method of driving a shaft coupled to a hydraulic load, comprising the steps of:
- applying torque to the shaft with a first motor; and
- applying torque to the shaft with a second motor, wherein torque is applied to the shaft simultaneously by the first motor and the second motor for a period of time wherein;
- the hydraulic load is driven in response to a flow of hydraulic fluid delivered by a pump which is powered by an engine operable at grade operation and idle operation,
- the first motor torque applying step includes the step of applying torque to the shaft during idle operation and grade operation, and
- the second motor torque applying step includes the step of applying torque to the shaft during grade operation and applying no torque to the shaft during idle operation.
- 3. A method of driving a shaft coupled to a hydraulic load, comprising the steps of:
- applying torque to the shaft with a first motor; and
- applying torque to the shaft with a second motor, wherein torque is applied to the shaft simultaneously by the firs motor and the second motor for a period of time wherein
- the first torque applying step further includes the step of mechanically coupling the first motor to the shaft during both idle operation and grade operation, and
- the second torque applying step further includes the step of mechanically decoupling the second motor from the shaft during idle operation, and mechanically coupling the second motor to the shaft during grade operation.
- 4. A method of driving a shaft coupled to a hydraulic load, comprising the steps of:
- applying torque to the shaft with a first motor; and
- applying torque to the shaft with a second motor, wherein torque is applied to the shaft simultaneously by the first motor and the second motor for a period of time wherein;
- the second torque applying step further includes the step of mechanically coupling the second motor to the shaft during grade operation with a slip clutch.
- 5. The method of claim 2, wherein:
- the first motor torque applying step further includes the step of allowing the first motor to be in fluid communication with the flow of hydraulic fluid during both idle operation and grade operation, and
- the second motor torque applying step further includes the step of preventing the second motor from being in fluid communication with the flow of hydraulic fluid during idle operation, and causing the second motor to be in fluid communication with the flow of hydraulic fluid during grade operation.
- 6. The method of claim 5, wherein the second motor torque applying step further includes the step of preventing the second motor from being in fluid communication with the flow of hydraulic fluid during idle operation with a pressure sensitive valve.
- 7. The method of claim 5, wherein:
- the first motor torque applying step further includes the step of mechanically coupling the first motor to the shaft during both idle operation and grade operation, and
- the second motor torque applying step further includes the step of mechanically decoupling the second motor from the shaft during idle operation, and mechanically coupling the second motor to the shaft during grade operation.
- 8. A system for driving a fan shaft in response to a flow of hydraulic fluid delivered by a pump which is powered by an engine operable at idle speed and at grade speed, comprising:
- a first motor coupled to said fan shaft in fluid connection with said pump during idle operation and during grade operation;
- a second motor coupled to said fan shaft; and
- a fluid connection for placing said second hydraulic motor into fluid connection with said pump during grade operation and preventing said second hydraulic motor from being in fluid connection with said pump during idle operation.
- 9. The system of claim 8, wherein said first motor is in mechanical driving connection to said shaft during idle operation and during grade operation.
- 10. The system of claim 9, further comprising a mechanical connection which connects said second hydraulic motor to said shaft during grade operation and disconnects said second hydraulic motor from said shaft during idle operation.
- 11. The system of claim 10, wherein said mechanical connection includes a slip clutch.
- 12. The system of claim 8, wherein said fluid connection includes a pressure sensitive valve.
- 13. A system for driving a fan shaft in response to a flow of hydraulic fluid delivered by a pump which is powered by an engine operable at idle speed and at grade speed, comprising:
- a first hydraulic motor in mechanical driving connection to said shaft during idle operation and during grade operation;
- a second hydraulic motor; and
- a mechanical connection which connects said second hydraulic motor to said shaft during grade operation and disconnects said second hydraulic motor from said shaft during idle operation.
- 14. The system of claim 13, wherein said first hydraulic motor is in fluid connection with said pump during idle operation and during grade operation.
- 15. The system of claim 14, further comprising a fluid connection for placing said second hydraulic motor into fluid connection with said pump during grade operation and preventing said second hydraulic motor from being in fluid connection with said pump during idle operation.
- 16. The system of claim 15, wherein said fluid connection includes a pressure sensitive valve.
- 17. The system of claim 13, wherein said mechanical connection includes a slip clutch.
- 18. A hydraulic motor system for driving a shaft which is connected to an automotive cooling fan in response to a flow of hydraulic fluid delivered by a fixed displacement pump which is powered by a variable speed engine operable at idle speed and at grade speed, comprising:
- a first hydraulic motor in fluid connection with said pump during idle operation and during grade operation, and in mechanical driving connection to said shaft during idle operation and during grade operation;
- a second hydraulic motor;
- a slip clutch which connects said second hydraulic motor to said shaft during grade operation and disconnects said second hydraulic motor from said shaft during idle operation; and
- a pressure sensitive valve for placing said second hydraulic motor into fluid connection with said pump during grade operation and preventing said second hydraulic motor from being in fluid connection with said pump during idle operation.
RELATED APPLICATION
This application is a continuation of Ser. No. 08/341,426 filed Nov. 17, 1994, now U.S. Pat. No. 5,561,778.
US Referenced Citations (10)
Foreign Referenced Citations (1)
Number |
Date |
Country |
3626013 |
Sep 1987 |
DEX |
Non-Patent Literature Citations (2)
Entry |
The Gerotor-information packet describing a positive displacement pumping unit consisting of an inner and an outer rotor, 6 pgs. |
Research Disclosure, "Hydraulic Powered Steering & Cooling System With Energy Savings Circuit", No. 369, Jul. 1994, Great Britain. |
Continuations (1)
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Number |
Date |
Country |
Parent |
341426 |
Nov 1994 |
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