Vickers, Inc.

Michael R McCarty

Rajamouli Gunda

Richard Scott Leemhuis

Melvin A Rode

James A Kessler

Robert C Hodges

Roy T Burgess

Frank Herta

Robert W Stephens

A rotary hydraulic machine which includes a housing having a shaft mounted for rotation within the housing about a shaft axis. A cylinder block is coupled to the shaft for co-rotation with the shaft within the housing and includes a plurality of cylinders disposed in a circumferential array parallel to and surrounding the shaft axis. A piston is disposed to reciprocate within each of the cylinders and is coupled to a yoke for determining displacement of the pistons within the cylinders. A valve plate is mounted on a valve block and includes kidney-shaped slots for registering with the cylinders as the cylinder block rotates, and thereby connecting the cylinders to pump input and output ports. A microprocessor-based controller is externally mounted on the pump valve block and includes internal memory having various remotely-selectable control programs prestored therein. Sensors responsive to pump operating conditions are connected to the pump control electronics, and include a first sensor responsive to yoke position, a pressure sensor responsive to pump output pressure and a speed sensor responsive to angular velocity of shaft rotation. All of the electronic components are mounted on the valve block.

Power transmission

A rotary hydraulic machine which includes a housing having a shaft mounted for rotation within the housing about a shaft axis. A cylidner block is coupled to the shaft for co-rotation with the shaft within the housing and includes a plurality of cylinders disposed in a circumferential array parallel to and surrounding the shaft axis. A piston is disposed to reciprocate within each of the cylinders and is coupled to a yoke for determining displacement of the pistons within the cylinders. A valve plate is mounted on a valve block and includes kidney-shaped slots for registering with the cylinders as the cylinder block rotates, and thereby connecting the cylinders to pump input and output ports. A microprocessor-based controller is externally mounted on the pump valve block and includes internal memory having various remotely-selectable control programs prestored therein. Sensors responsive to pump operating conditions are connected to the pump control electronics, and include a first sensor responsive to yoke position, a pressure sensor responsive to pump output pressure and a speed sensor responsive to angular velocity of shaft rotation. All of the electronic components are mounted on the valve block.

An electrohydraulic servo system which includes a plurality of pressure compensated flow control servo valves for feeding hydraulic fluid from a variable displacement pump to associated actuators and loads. A closed-loop velocity-control servo system is coupled to each servo valve, and is responsive to velocity command inputs from an operator and to feedback signals from the respective loads for providing flow control signals to the respective servo valves. A pump controller receives the valve flow control signals, derives associated valve flow rates from predetermined functional characteristics of the pressure compensated valves, and obtains a total flow demand as a function of the sum of the indicated individual valve flow rates. A pump displacement command is derived as a combined function of total flow demand and pump speed to accommodate volumetric inefficiencies which vary with speed, and the displacement command signal is fed to a pump displacement servo control loop for controlling pump output. Displacement command is limited as a function of power available at the engine coupled to the pump to prevent engine stall.

An electrohydraulic control system which includes first and second electrically controlled fully variable hydraulic pumps adapted to be driven by the vehicle engine. In the specific embodiment of the invention herein disclosed, the first pump is coupled to the steering and braking control valves, and the second pump is coupled to the bucket and hoist control valves. An electrically controlled poppet valve selectively interconnects the respective pump outputs. Operator-responsive controllers, namely a bucket/hoist joy-stick controller, a vehicle propulsion controller and a steering controller, provide associated electrical signals as respective functions of operator demand. Electrically operated valves control application of hydraulic fluid to the bucket and hoist drive mechanisms, and pressure and position sensors are connected to such valves and actuating mechanisms. An electronic controller receives inputs indicative of operator demands, pump outputs, and operation at the hoist and bucket, and selectively controls or modulates the cartridge valve, the pumps, and the hoist and bucket valves for operation at optimum efficiency.

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Troy, MI, United States of America

Michael R McCarty