Deere + Company

Sanjay Ishvarlal Mistry

Yifei Raymond Hou

Mark Allen Bergene

Scott Allen Toppin

Benjamin Michael Witte

Lawrence Vernon Anderson

John W Schletzbaum

Raymond Yifei Hou

Ronald Lee Mayfield

Dennis Royal Yoder

A system for monitoring the charge flow in a hydrostatic system. The system provides a sharp edge orifice restriction in the drain from the hydrostatic pump, creating a back pressure in the drain that is proportional to the fluid flow through the drain. A pressure switch mounted in the pump case, or in the drain, detects the back pressure in the drain. The pressure switch is designed to be activated at a back pressure that corresponds to the intended charge flow at a specific engine speed. During operation, if the back pressure is not sufficient to cause the pressure switch to be activated at the predetermined engine speed or at a faster engine speed, the charge flow is not sufficient and a warning signal is generated.

Hydrostatic system with charge flow monitoring

A control system controls a hydrostatic transmission having an engine driven variable displacement pump coupled to a fixed displacement motor. The pump has a swashplate which is controlled by a control signal generated by the control system. The control system includes a speed command signal generator, a motor speed sensor for generating a sensed motor speed signal, an engine speed sensor for generating an engine speed signal, and a control unit which generates the control signal as a function thereof. The control unit generates a desired motor speed signal as a function of the speed command signal and the engine speed signal, generates a feed-forward command signal as a function of the desired motor speed signal, generates a difference signal as a difference between the desired motor speed signal and the sensed motor speed signal, generates an integral signal by applying an integral function to the difference signal, generating a sum signal as a summation of the feed-forward command signal and the integral signal, and generating the control signal as a function of the sum signal.

Control system for hydrostatic transmission

A control system is provided for a tracked vehicle drive/steering system having an engine driven hydraulic steering pump which drives a hydraulic steering motor. The steering pump is responsive to steering control signals representing a status of an operator manipulated steering wheel. The steering motor provides an input to a differential track drive mechanism which responds to manipulation of the steering wheel and drives left and right tracks to turn the vehicle. The control system includes a control unit which receives signals from an engine speed sensor, a steering motor rotation speed and direction sensor, and the steering control signals. The control unit, when the steering control signals indicate that the steering wheel is turned in a direction opposite to a direction of rotation of the steering motor, generating and saving a first ratio value representing a ratio of the motor speed to the pump speed. Then, if the steering control signal is unchanged after a certain time duration, the control unit generates and saves a second ratio value representing a later ratio of the motor speed to the pump speed. The control unit then calculates a difference value representing a difference between the first and second ratio values, and generates a fault signal if the difference value has a magnitude which is less than a predetermined magnitude. Thus, the control system generates a fault signal when the sensed signals indicate that the steering pump swashplate position is not changing as it should in response to changes in steering wheel position.

Tracked vehicle steering system with failure detection

A control system is provided for a tracked vehicle drive/steering system having an engine driven hydraulic steering pump which drives a hydraulic steering motor. The steering pump is responsive to steering control signals representing a status of an operator manipulated steering wheel. The steering motor provides an input to a differential track drive mechanism which responds to manipulation of the steering wheel and drives left and right tracks to turn the vehicle. The control system includes a control unit which receives signals from an engine speed sensor, a steering motor rotation speed and direction sensor, and the steering control signals. The control unit calculates a motor speed threshold value as a function of sensed engine speed and steering control signals, and generates a fault signal as a function of a relationship between the steering motor speed signal and a motor speed threshold value. The control unit generates an overspeed fault signal when the steering motor speed signal is greater than the motor speed threshold value or less than a negative motor speed threshold value, and generates a data conflict fault signal when the steering motor speed signal is less than a negative minimum motor speed threshold value or greater than a minimum motor speed threshold value. The control unit, when the vehicle is not being commanded to turn by the steering control signals, generates a minimum threshold value, and generates an overspeed fault signal when the motor speed signal is greater than the minimum threshold value or is less than a negative minimum threshold value.

Tracked vehicle steering system with steering pump monitoring

A steering control system for a tracked vehicle includes an engine driven variable displacement steering pump which drives a hydraulic motor. A control system senses steering wheel position, vehicle speed, engine speed and forward/reverse vehicle direction. As a function of these sensed inputs, a control signal is generated and is used to control the swashplate angle of an engine-driven variable displacement pump which drives a steering motor which drives a differential track drive mechanism. The control system also determines a ratio of motor speed to vehicle speed and generates a powerboost signal when the ratio exceeds a threshold value. The powerboost signal is communicated to the engine controller which causes the engine to increase its power output. This modifies the engine fuel delivery curve based on the steering system power requirement and increases the power available for turning the vehicle.

Growing community of inventors

Cedar Falls, IA, United States of America

Sanjay Ishvarlal Mistry