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US 4,399,886 AGranted
Controls for variable displacement motor and motors
AssigneeSundstrand Corporation
InventorFrederic W. Pollman
Life of this patent
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AssigneeSundstrand Corporation
InventorFrederic W. Pollman
Estimating the term…
A control for a variable displacement motor which utilizes a motor speed sensitive signal for moving the displacement of the motor toward a zero displacement setting position including a device for generating a conditioned variable signal representative of motor speed, circuitry for receiving said signal and upon the signal reaching a predetermined intermediate value applying the signal to the control device for motor displacement for causing reduction in motor displacement and with various devices in the circuit for modifying the variable signal to provide a desired relation between motor speed and motor displacement. Utilization of such controls individually associated with plural variable displacement motors driving vehicle wheels and driven by one pump protects against spin-out of one of the wheels. The variable motor control is usable in a load-compensated system wherein at least one motor is associated with a drive at the front of the vehicle and another motor with the drive at the rear of the vehicle and with the control circuit having a valve responsive to the pressure condition in the system pressure lines connected between the pump and motors for differing adjustment of the displacement of the front and rear drive motors. The variable motor control is usable in a vehicle drive system with separate drives on the right and left-hand side of the vehicle to obtain steer compensation whereby the displacement of at least a pair of motors associated with the separate drives at the right and left sides of the vehicles are controlled by a circuit which includes a valve responsive to a steering signal whereby the displacement of the motors in their respective drives is varied to apply torque to the wheels in a relation to that required in connection with turning of the vehicle.
A hydrostatic drive system for a pair of drive shafts with anti-slip drive characteristics comprising, a pair of variable displacement fluid motors associated one with each of said drive shafts, a pump in closed circuit with said motors with said motors being connected in parallel with said pump, a pair of movable displacement-setting members associated one with each motor, a pair of signal-generating means associated one with each motor and with each signal-generating means generating a variable signal which increases in value as the speed of the associated motor increases, and control devices connected one to each of said displacement-setting members and responsive to an increase in the variable signal indicating increased motor speed for reducing displacement of the associated motor with the maximum value of the variable signal achieving zero output torque.
A control for a variable displacement motor having a movable displacement-setting member which is movable to a position to set zero motor displacement comprising, a control device connected to said displacement-setting member and actuable by a variable signal to move the last-mentioned member toward a zero displacement-setting position, means for generating a conditioned variable signal representative of motor speed, and means responsive to a predetermined intermediate value of said variable signal for communicating said signal to said control device for reducing motor displacement.
A load-compensated control for a variable displacement motor having a movable displacement-setting member which is movable to a position to set motor displacement comprising, a control device connected to said displacement-setting member and actuable by a variable signal to move the last-mentioned member toward a zero displacement-setting position, means for generating a variable signal representative of motor speed, means responsive to a predetermined value of said variable signal for communicating said signal to said control device for reducing motor displacement, and means responsive to the system pressure of fluid supplied to said motor for modifying the value of said signal.
A load-compensated control for each of plural variable displacement motors usable in separate drives at the front and rear of a vehicle for changing transmission ratio when system loading changes and wherein a pump is in closed fluid system with said motors, a servo control for each of said motors, a displacement control for each of said servo controls, means associated with each motor including a speed pump driven by the motor for applying a motor speed sensitive fluid signal to the associated displacement and servo control for control of the displacement of the associated motor, a plurality of pressure regulator valves associated one with each motor and having an output in a fluid circuit with said speed pump and an input connected to the closed fluid system and being piloted by said input to increase the speed sensitive signal as the input pressure increases, a first of the pressure regulator valves associated with the control for the front drive motor having said input connected to the closed fluid system in a manner whereby the input pressure increases upon forward acceleration of the front drive motor, and a second of the pressure regulator valves associated with the control for the rear drive motor has said input connected to the closed fluid system in a manner whereby the input pressure increases as the rear drive motor decelerates.
A steer compensated control for a variable displacement motor having a movable displacement-setting member which is movable to a position to set motor displacement comprising, a control device connected to said displacement-setting member and actuable by a variable signal to move the last-mentioned member toward a negative displacement-setting position, means for generating a variable motor speed signal, means responsive to a predetermined value of said variable signal for communicating said signal to said control device for reducing motor displacement, and means responsive to a steer command signal for modifying the value of said variable signal.
A steer compensated control for each of plural variable displacement motors usable in separate traction drives at opposite sides of a vehicle for changing transmission ratio when steering the vehicle, a servo control for each of said motors, a displacement control for each of said servo controls, means responsive to the speed of a motor for controlling the displacement thereof, and means associated with each motor and responsive to a steer command signal for modifying the displacement of the associated motor.
A steer compensated control for each of plural variable displacement motors usable in separate traction drives at opposite sides of a vehicle for changing transmission ratio when steering the vehicle, each of said controls comprising, a servo control for setting displacement of a motor, a displacement control for said servo controls, means for generating a motor speed-sensitive signal, and a pressure regulator valve having an output additive to said speed-sensitive signal and having a pilot section operable on the pressure-regulator valve to control the output thereof, and a steer command system including means for generating either a right turn or a left turn signal, and means connecting the steer command system to the pilot section of the pressure regulator associated with the motor for the traction drive at the right side of the vehicle to deliver the right turn signal thereto and increase the output thereof and reduce the displacement of the last-mentioned motor, and means connecting the steer command system to the pilot section of the pressure regulator associated with the motor for the traction drive at the left side of the vehicle to deliver the left turn signal thereto and increase the output thereof and reduce the displacement of the last-mentioned motor.
Dependencies are inferred from the claim text.