Hydraulic rotary machine

Abstract

A piston pump/motor includes a cylinder block rotated with a shaft; a piston slidably inserted into a cylinder that is formed on the cylinder block; a shoe rotatably connected to a tip end portion of the piston, the shoe being in sliding contact with the tip end portion; and a swash plate with which the shoe is in sliding contact. The shoe has a piston slide portion in sliding contact with the piston and a swash-plate slide portion in sliding contact with the swash plate; a shoe body portion on which the piston slide portion and the swash-plate slide portion are mounted; and a first lock portion and a second lock portion provided across the shoe body portion, and the piston slide portion and the swash-plate slide portion, respectively, the first lock portion and the second lock portion regulating relative rotation between the shoe body portion, and the piston slide portion and the swash-plate slide portion.

1 . A hydraulic rotary machine comprising:
 a cylinder block to which a shaft is connected, the cylinder block being configured to be rotated with the shaft;   a plurality of cylinders formed on the cylinder block, the plurality of cylinders being disposed at a predetermined interval in a circumferential direction of the shaft;   a piston slidably inserted into the cylinder, the piston defining a volume chamber inside the cylinder;   a shoe rotatably connected to a tip end portion of the piston, the shoe being in sliding contact with the tip end portion; and   a swash plate with which the shoe is in sliding contact, wherein
 the shoe has 
 a slide portion made of resin provided on at least either one of a portion in sliding contact with the piston and a portion in sliding contact with the swash plate; 
 a shoe body portion on which the slide portion is mounted; and 
 a lock portion provided across the shoe body portion and the slide portion, the lock portion regulating relative rotation between the shoe body portion and the slide portion, and
 the lock portion has 
 a dent portion formed on either one of the shoe body portion and the slide portion; and 
 a projecting portion formed on the other of the shoe body portion and the slide portion, the projecting portion being locked by the dent portion. 
 
   
     
     
         2 . The hydraulic rotary machine according to  claim 1 , wherein
 the piston has a spherical surface seat formed on the tip end portion,   the shoe body portion has a receiving portion receiving the spherical surface seat of the piston,
 the receiving portion has 
 a body portion; and 
 a reduced-diameter portion whose diameter is reduced from the body portion, the reduced-diameter portion regulating removal of the spherical surface seat from the receiving portion, 
   the shoe has a piston slide portion as the slide portion provided on an inner periphery of the receiving portion, the piston slide portion being in sliding contact with the spherical surface seat of the piston, and   the lock portion is provided across the body portion of the receiving portion and the piston slide portion.   
     
     
         3 . The hydraulic rotary machine according to  claim 1 , wherein
 the shoe body portion has a flat plate portion formed having a disc shape and faced with the swash plate,   the shoe has a swash-plate slide portion as the slide portion provided on the flat plate portion so as to cover an outer peripheral surface of the flat plate portion, the swash-plate slide portion being in sliding contact with the swash plate, and   the lock portion is provided across the outer peripheral surface of the flat plate portion and the swash-plate slide portion.   
     
     
         4 . The hydraulic rotary machine according to  claim 1 , wherein
 the dent portion is provided on the shoe body portion, and   the projecting portion is provided on the slide portion.   
     
     
         5 . The hydraulic rotary machine according to  claim 1 , wherein
 the dent portion is formed by a curved surface.