Variable displacement pump regulator

Abstract

A regulator includes a feedback lever configured to move a compensating sleeve in an axial direction of a compensating spool. The compensating spool and the compensating sleeve form: a self-pressure introduction chamber, into which a self-pressure of a pump is introduced; and a pressure adjuster configured to output a control pressure from the self-pressure introduction chamber to a large-diameter pressure receiver of a servo piston. The compensating sleeve includes a stepped portion, to which a pressure in a direction in which a control spring urges the compensating spool is applied when the self-pressure is introduced into the self-pressure introduction chamber.

1 . A variable displacement pump regulator comprising:
 a servo piston configured to change a delivery flow rate of a variable displacement pump driven by a prime mover;   a feedback lever for detecting a position of the servo piston;   a compensating spool urged by a control spring in a direction toward one end of the compensating spool; and   a compensating sleeve positioned surrounding the compensating spool and configured to move, by operation of the servo piston and the feedback lever, in an axial direction of the compensating spool via an engagement portion engaged with the feedback lever, wherein   the compensating spool and the compensating sleeve form:
 a delivery pressure introduction chamber, into which a delivery pressure of the pump is introduced; and 
 a pressure adjuster configured to output a control pressure from the delivery pressure introduction chamber to a large-diameter pressure receiver of the servo piston, and 
   the compensating sleeve includes a stepped portion to which a pressure in the direction toward the one end of the compensating spool is applied when the delivery pressure is introduced into the delivery pressure introduction chamber.   
     
     
         2 . The variable displacement pump regulator according to  claim 1 , wherein
 the stepped portion is formed on an opposite side of the delivery pressure introduction chamber to the pressure adjuster, the stepped portion being formed by reducing an internal diameter of the compensating sleeve.   
     
     
         3 . The variable displacement pump regulator according to  claim 1 , wherein
 the delivery pressure introduction chamber is a self-pressure introduction chamber, into which a self-pressure, which is the delivery pressure of the pump, is introduced, and   the compensating spool and the compensating sleeve form a counterpart-pressure introduction chamber, into which a counterpart-pressure, which is a delivery pressure of another variable displacement pump, is introduced, the counterpart-pressure introduction chamber being formed at a position that is away from the self-pressure introduction chamber toward an opposite side to the pressure adjuster.   
     
     
         4 . The variable displacement pump regulator according to  claim 3 , wherein
 the counterpart-pressure introduction chamber has a diameter less than that of the self-pressure introduction chamber, and   the compensating sleeve includes a stepped portion to which a pressure in the direction toward the one end of the compensating spool is applied when the counterpart-pressure is introduced into the counterpart-pressure introduction chamber.   
     
     
         5 . The variable displacement pump regulator according to  claim 2 , wherein
 the delivery pressure introduction chamber is a self-pressure introduction chamber, into which a self-pressure, which is the delivery pressure of the pump, is introduced, and   the compensating spool and the compensating sleeve form a counterpart-pressure introduction chamber, into which a counterpart-pressure, which is a delivery pressure of another variable displacement pump, is introduced, the counterpart-pressure introduction chamber being formed at a position that is away from the self-pressure introduction chamber toward an opposite side to the pressure adjuster.   
     
     
         6 . The variable displacement pump regulator according to  claim 5 , wherein
 the counterpart-pressure introduction chamber has a diameter less than that of the self-pressure introduction chamber, and   the compensating sleeve includes a stepped portion to which a pressure in the direction toward the one end of the compensating spool is applied when the counterpart-pressure is introduced into the counterpart-pressure introduction chamber.