Total power fluid system

A total fluid power system comprising:

• a fluid reservoir;
• a variable displacement fluid pump having an inlet operatively connected to the reservoir and an outlet providing a flow of pressurized fluid;
• a variable displacement, variable speed fluid motor having an inlet connected to the pump outlet and providing a torque output;
• pressure sensor means connected to the pump outlet responsive to the pressure of pressurized fluid thereat to provide a pressure signal proportional thereto;
• reference pressure means providing a reference pressure signal proportional to a predetermined pump outlet pressure;
• pump displacement means operatively associated with the pump and connected to the pressure sensor means and pressure reference means to increase and decrease pump displacement in response respectively to a pressure signal smaller and larger than the pressure of reference signal;
• motor speed sensor means connected to the motor responsive to the speed thereof to provide a speed signal proportional thereto;
• input speed means providing an input speed signal;
• and motor displacement means operatively associated with the motor and connected to the motor speed sensor means and the input speed means to increase and decrease motor displacement in response to speed error signals respectively representative of a speed signal smaller and larger than the input speed signal whereby the pump output flow is changed by changing the pump displacement so as to maintain the motor speed and the motor torque output is changed by changing the motor displacement so as to match the motor loading

A total fluid power system comprising:

• a fluid reservoir;
• a variable displacement fluid pump having an inlet operatively connected to the reservoir and an outlet for providing a flow of pressurized fluid in proportion to the displacement;
• a variable displacement fluid motor having an inlet connected to the pump outlet and a rotatable output shaft providing an output torque proportional to the displacement;
• a pressure transducer positioned at the pump outlet providing actual pressure signals proportional to the actual pressure thereat;
• reference pressure means providing a predetermined reference pressure signal proportional to a predetermined operating stand-by pump outlet pressure;
• pressure error summing means connected to the pressure transducer and the reference pressure means for summing the actual and reference pressure signals and providing increase and decrease pressure error signals in response respectively to pressure signals smaller and larger than the reference pressure signal;
• a pump displacement transducer operatively connected to the pump providing displacement signals proportional to the displacement of the pump;
• pressure error-displacement summing means operatively connected to the pressure error summing means and the pump displacement transducer for summing the pressure error and pump displacement signals and providing increase and decrease pump actuation signals in response respectively to pressure error signals smaller and larger than the pump displacement signals;
• pump actuator means operatively associated with the pump and the pressure error-displacement summing means for increasing and decreasing the pump displacement in response respectively to the increase and decrease pump actuation signals;
• a shaft speed transducer operatively connected to the motor output shaft and providing speed signals proportional to the rotative speed of the shaft;
• input speed means providing an input speed signal;
• speed error summing means connected to the speed transducer and to the input speed means for summing the speed and input speed signals and providing increase and decrease speed error signals in response respectively to speed signals smaller and larger than the speed input signal;
• a motor displacement transducer operatively connected to the motor providing displacement signals proportional to the displacement of the motor;
• speed error-displacement summing means operatively connected to the speed error summing means and the motor displacement transducer for summing the speed error and motor displacement signals and providing increase and decrease motor actuation signals in response respectively to speed error signals smaller and larger than the motor displacement signals;
• and motor actuator means operatively associated with the motor and the speed error-displacement summing means for increasing and decreasing the motor displacement in response respectively to the increase and decrease motor actuation signals.

A total fluid power system comprising:

• a fluid reservoir;
• a variable displacement fluid pump having an inlet operatively connected to the reservoir and an outlet for providing pressurized fluid;
• a variable displacement fluid motor having an inlet connected to the pump outlet and an output shaft rotatable by the pressurized fluid;
• pump control means interposed between the pump outlet and the motor inlet operatively associated with the pump for changing the displacement thereof in response to changes in the pressure of the pressurized fluid between the pump outlet and the motor inlet;
• motor speed sensor means operatively associated with the motor output shaft for providing an indication of actual speed and direction of rotation of the motor output shaft;
• operator input means for providing an indication of the desired speed and direction of rotation of the motor output shaft;
• motor displacement means operatively associated with the motor, the motor speed sensor means, and the operator input means for changing the displacement of the motor in response to differences between the indications of the actual and desired speed and direction of rotation of the output shaft.

A total fluid power system comprising:

• a variable displacement fluid pump having an inlet operatively connected to a fluid reservoir and an outlet for providing pressurized fluid;
• a first variable displacement fluid motor having an inlet connected to the pump outlet and a first output shaft rotatable by the pressurized fluid;
• a second variable displacement fluid motor having an inlet connected to the pump outlet and a second output shaft rotatable by the pressurized fluid;
• pump control means connected to the pump outlet and operatively associated with the pump for changing the displacement thereof in response to the changes in the pressure of the pressurized fluid at the pump outlet;
• first motor speed sensor means operatively associated with the first output shaft for providing an indication of actual speed and direction of rotation of the first motor output shaft;
• operator input means for providing indication of desired speed and direction of rotation of the first and second motor output shafts;
• motor displacement means operatively associated with the first motor, the first motor speed sensor means, and the operator input means for changing the displacement of the first motor in response to differences between the indications of actual and desired speed and direction of rotation of the first output shaft, said motor displacement means operatively associated with the second motor, the second motor speed sensor means, and the operator input means for changing the displacement of the second motor in response to differences between the indications of the actual and desired speed and direction of rotation of the second output shaft.

A total fluid power system comprising:

• a fluid reservoir;
• a variable displacement fluid pump having an inlet operatively connected to the reservoir and an outlet providing pressurized fluid;
• a variable displacement, variable speed fluid motor having an inlet connected to the pump outlet and an output shaft rotatable by the pressurized fluid;
• pump control means operatively associated with the pump and the motor responsive to changes in the pressure of the pressurized fluid at the pump outlet and to a predetermined displacement of the motor to change the displacement of the pump;
• motor control means operatively associated with the motor and the pump control means responsive to changes in the speed of the motor shaft and to a predetermined pressure of pressurized fluid at the pump outlet to change the motor displacement.

A total fluid power system comprising:

• a fluid reservoir;
• a variable displacement fluid pump having an inlet operatively connected to the reservoir and an outlet providing pressurized fluid;
• a variable displacement, variable speed fluid motor having an inlet connected to the pump outlet;
• an engine drivingly connected to the pump;
• pump control means operatively associated with the pump and the engine responsive to changes in the pressurized fluid between the pump outlet and the motor inlet and to a predetemined change in the engine speed to change the pump displacement;
• and motor control means operatively associated with the motor and the pump control means responsive to changes in the speed of the motor and a predetermined pressure of pressurized fluid between the pump outlet and the motor inlet to change the displacement of the motor.

In an engine powered vehicle, a total fluid power system comprising:

• a fluid reservoir;
• a variable displacement, engine driven fluid pump having an inlet operatively connected to the reservoir and an outlet for providing pressurized fluid;
• first and second variable displacement, variable speed, fluid wheel motors having inlets connected to the pump outlet and first and second wheel shafts rotatable by the pressurized fluid, pump control means operatively associated with the pump, the engine, and the first and second wheel motors responsive to changes in the pressure of pressurized fluid at the pump outlet, to a predetermined change in the engine speed, and to a predetermined displacement of either the first and second wheel motor and the larger of the changes in the speed of the first and second wheel motors to change the displacement of the pump;
• and first and second wheel motor control means operatively associated, respectively, with the first and second wheel motors and the pump control means responsive, respectively, to changes in the speed of the first and second wheel shafts and to a predetermined pressure of the pressurized fluid at the pump outlet to respectively change the first and second wheel motor displacements.

In an engine powered vehicle, a total fluid power system comprising:

• a fluid reservoir;
• a variable displacement, engine driven fluid pump having an inlet operatively connected to the reservoir and an outlet for providing pressurized fluid;
• first and second variable displacement;
• variable speed, fluid wheel motors having inlets connected to the pump outlet and having first and second wheel shafts, respectively, rotatable by the pressurized fluid to drive first and second vehicle drive wheels;
• a pressure transducer positioned at the pump outlet providing a pressure signal proportional to the pressure thereat;
• reference pressure means providing a predetermined reference pressure signal proportional to a predetermined stand-by pump outlet pressure;
• pressure error summing means connected to the pressure transducer and the reference pressure means for summing the pressure and reference pressure signals and providing pressure error signals in response to a pressure signal smaller and larger than the reference pressure signal;
• a pump displacement transducer operatively connected to the pump providing a displacement signal proportional to the displacement of the pump;
• pressure error-displacement summing means operatively connected to the pressure error summing means and the pump displacement transducer for summing the pressure error and pump displacement signals and providing pump actuation signals in response to a pressure error signal smaller and larger than the pump displacement signal;
• pump actuator means operatively associated with the pump and the pressure error-displacement summing means for increasing and decreasing the pump displacement in response to pump actuation signals;
• first and second wheel speed transducers operatively connected to the first and second wheel motors, respectively, and providing wheel speed signals proportional to the respective rotative speed of the first and second motor output shafts;
• first and second input speed means respectively providing first and second input speed signals;
• first speed error summing means connected to the first wheel speed transducer and to the first input speed means for summing the first actual and input speed signals and providing first speed error signals in response respectively to a first actual speed signal smaller and larger than the first speed input signal;
• second speed error summing means connected to the second wheel speed transducers and to the second input speed means for summing the second actual and input speed signals and providing second speed error signals in response respectively to a second actual speed signal smaller and larger than the second speed input signal;
• first and second motor displacement transducers operatively connected to the first and second motors providing first and second displacement signals proportional to the displacement of the first and second motors, respectively;
• first speed error-displacement summing means operatively connected to the first speed error summing means and the first motor displacement transducer for respectively summing the first speed error and motor displacement signals and providing first motor actuation signals in response respectively to a first speed error signal smaller and larger than the first motor displacement signal;
• and first motor actuator means operatively associated with the first motor and the first speed error-displacement summing means for increasing and decreasing the first motor displacement in response respectively to first positive and negative motor actuation signals;
• second speed error-displacement summing means operatively connected to the second speed error summing means and the second motor displacement transducer for respectively summing the second speed error and motor displacement signals and providing second motor actuation signals in response respectively to a second speed error signal smaller and larger than the first motor displacement signal;
• and second motor actuator means operatively associated with the second motor and the second speed error-displacement summing means for increasing and decreasing the second motor displacement in response respectively to second motor actuation signals.