Hydrostatic transmission
AssigneeBriggs & Stratton Corporation
InventorsRobert Carlson, Thomas D. Blum, Tandrea Lea Sperfslage
Life of this patent
Estimating the term…
Abstract
A transmission for a vehicle includes a fixed displacement pump operable to produce a high pressure flow and a fixed displacement motor. A fluid flow path is disposed between the pump and the motor. The fluid flow path is integrated into a housing containing at least one of the pump and the motor. A single control valve controls the direction and the speed of the motor.
Claims65
A transmission for a vehicle, the transmission comprising:
- a fixed displacement pump operable to produce a high pressure flow;
- a fixed displacement motor;
- a fluid flow path between the pump and the motor, the fluid flow path integrated into a housing containing at least one of the pump and the motor;
- and
- a single control valve for controlling the direction and the speed of the motor, wherein the control valve includes a rotary valve plate and a stationary valve plate.
A hydrostatic transmission for a vehicle, the hydrostatic transmission comprising:
- a fluid pump;
- a fluid motor;
- a rotary control valve configured to oscillate independent of the movement of the pump and the motor;
- a single control interface configured to control both a speed and a direction of the motor;
- and
- a linkage between the rotary control valve and the interface.
A hydrostatic transmission for a vehicle, the hydrostatic transmission comprising:
- a fluid pump;
- a fluid motor;
- a rotary control valve configured to oscillate independent of the movement of the pump and the motor;
- and
- a single control interface configured to control both a speed and a direction of the motor, wherein the motor, the pump and the control valve are disposed in a common housing.
A transmission comprising:
- a pump configured to discharge a flow of fluid at a first pressure;
- a motor configured to rotate in response to a flow of fluid in a first flow path;
- a first valve movable to vary the flow of fluid in the first flow path;
- and
- a second valve movable between a first position and a second position at least partially in response to the first pressure to direct a portion of the flow of fluid to the first flow path and a remainder of the flow of fluid to a second flow path, wherein as the second valve moves toward the second position, additional flow is diverted from the second flow path to the first flow path to increase the speed of the motor, wherein the pump, the first valve, the motor, and the second valve are disposed in a common housing.
A hydrostatic transmission module for use with a small engine, the hydrostatic transmission module comprising:
- a module housing having a first chamber, and a second chamber in fluid communication with the first chamber;
- a fixed displacement pump disposed in the first chamber of the module housing, the fixed displacement pump operatively coupled to a crankshaft of the engine and configured to discharge a flow of fluid having a first pressure;
- a fixed displacement motor disposed in the second chamber of the module housing, the motor configured to rotate in response to the flow of fluid from the pump;
- a first valve operable to divide a flow of fluid from the pump into a first flow of fluid that flows to the motor and a second flow of fluid that flows to a sump;
- and
- a second valve disposed in the first flow and movable to vary the first flow of fluid to the motor.
Dependencies are inferred from the claim text.