Hydraulic motor control
AssigneeSundstrand Corporation
InventorFrederic W. Pollman
Life of this patent
Estimating the term…
Abstract
A control for a variable displacement motor and operable in either direction of rotation of the motor (10) and which acts on a servo cylinder (55) to set the position of a wash plate (50). The control includes a signal-setting valve (65) operable in response to the rate of fluid flow through the motor by sensing a pressure drop in a closed circuit line to the motor to set a variable control signal and the variable control signal is applied to the displacement-setting mechanism (56,55) for the motor to have a decrease in motor displacement related to an increase in the rate of fluid flow through the motor.
Claims17
A control for a variable displacement motor operable in either direction of rotation and having a movable member for setting motor displacement, positioning means including a servo member connected to said movable member for normally urging said movable member to a first position to set maximum motor displacement and for moving said movable member from said first position in response to a variable control signal, and means including a signal-setting valve operable in either direction of fluid flow through the motor and responsive to the rate of fluid flow therethrough for establishing said variable control signal generally proportional to said rate of fluid flow and which is applied to said member-positioning means.
A control for a variable displacement motor operable in either direction of rotation and having a movable member for setting motor displacement, positioning means including a servo cylinder connected to said movable member for normally urging said movable member to a first position to set maximum motor displacement and for moving said movable member from said first position in response to a variable control signal above a predetermined value, and means including a signal-setting valve having means responsive to the rate of fluid flow through the motor in either direction of fluid flow therethrough for establishing said variable control signal generally proportional to said rate of fluid flow and which is applied to said member-positioning means.
A control for a variable displacement motor operable in either direction of rotation and having a movable member for setting motor displacement;
- means including a displacement control valve and a servo cylinder connected to said movable member for normally urging said movable member to a first position to set maximum motor displacement and for moving said movable member from said first position in response to a variable control signal;
- a signal-setting valve having a valve member with a center position and movable therefrom to establish a variable control signal directed to said displacement control valve, said signal-setting valve having pilot means responsive to a pressure differential representative of the rate of fluid flow through the motor for positioning of the valve member, a pair of inlet connections for delivery of control pressure thereto, an outlet connection to tank, a pair of outlet connections to the displacement control valve, a pair of feedback pilots, outlet connections extended one to each of said feedback pilots;
- and said signal-setting valve and valve member having means operable when positioned at either side of the center position for modifying the control pressure to set the variable control signal and for directing the variable control signal to one of said feedback pilots.
A control for a variable displacement motor operable in either direction of rotation and having a movable member for setting motor displacement;
- means including a servo cylinder connected to said movable member for normally urging said movable member to a first position to set maximum motor displacement and for moving said movable member from said first position in response to a variable control signal;
- a signal-setting valve having a valve member with a closed centered position and movable therefrom to establish a variable control signal directed to said servo cylinder, said signal-setting valve having pilot means responsive to a pressure differential representative of the rate of fluid flow through the motor for positioning of the valve member, an inlet connection for delivery of control pressure thereto, a pair of outlet connections to tank, an outlet connection to the servo cylinder, a pair of feedback pilots, outlet connections extended one to each of said feedback pilots;
- and said signal-setting valve and valve member having means operable when positioned at either side of the closed centered position for modifying the control pressure to set the variable control signal and for directing the variable control signal to one of said feedback pilots.
A control for a variable displacement motor operable in either direction of rotation and having a movable member for setting motor displacement;
- means including a displacement control valve and a servo cylinder connected to said movable member for normally urging said movable member to a first position to set maximum motor displacement and for moving said movable member from said first position in response to a variable control signal;
- a signal-setting valve having a valve member with a closed centered position and movable therefrom to establish a variable control signal directed to said displacement control valve, said signal-setting valve having pilot means responsive to a pressure differential representative of the rate of fluid flow through the motor for positioning of the valve member, an inlet connection for delivery of control pressure thereto, and an outlet connection to tank;
- said signal-setting valve and valve member having means operable when positioned at either side of the closed centered position for modifying the control pressure to set the variable control signal;
- and means responsive to the variable control signal for positioning said displacement control valve.
A control for a variable displacement motor having a movable member for setting motor displacement;
- means including a servo cylinder connected to said movable member for normally urging said movable member to a first position to set maximum motor displacement and for moving said movable member from said first position in response to a variable control signal;
- a signal-setting valve having a valve member movable from a first position to establish a variable control signal, said signal-setting valve having pilot means responsive to a pressure differential representative of the rate of fluid flow through the motor for positioning of the valve member, an inlet connection for delivery of control pressure thereto, an outlet connection to tank, an outlet connection for delivery of the variable control signal, a pair of feedback pilots, outlet connections extended one to each of said feedback pilots;
- and said signal-setting valve and valve member having means operable when positioned away from said first position from modifying the control pressure to set the variable control signal and for directing the variable control signal to one of said feedback pilots.
A control for a variable displacement motor having a movable member for setting motor displacement;
- means inc1uding a displacement control valve and a servo cylinder connected to said movable member for normally urging said movable member to a first position to set maximum motor displacement and for moving said movable member from said first position in response to a variable control signal;
- a signal-setting valve having a valve member with a closed centered position and movable therefrom to establish a variable control signal directed to said displacement control valve, said signal-setting valve having pilot means responsive to a pressure differential representative of the rate of fluid flow through the motor for positioning of the valve member;
- a supply fluid line for directing fluid under pressure to said signal-setting valve and having a branch line extending to said displacement control valve for supplying fluid for operation of the displacement control valve;
- said signal-setting valve and valve member having means operable when the valve member is shifted from;
- the closed centered position for modifying the pressure in the fluid line to set the variable control signal;
- a control fluid line extended from said supply fluid line to deliver the variable control signal to a pilot for positioning said displacement control valve;
- and a pressure-immunizing orifice in said supply fluid line between said branch line and the control fluid line.
Dependencies are inferred from the claim text.