Hydraulic rotary machine and valve plate thereof

Abstract

It includes a plurality of cylinders formed on the cylinder block; a piston slidably inserted into the cylinder; a case accommodating the cylinder block; and a valve plate formed by a core member and a resin layer coating the core member, the valve plate being interposed between the cylinder block and an end cover of the case. The valve plate has a first land portion formed by the resin layer, the first land portion being in sliding contact with the cylinder block; and an outer-side non-contact portion provided closer to an outer side in a radial direction than the first land portion, the outer-side non-contact portion being separated away from the cylinder block. At least a part of the outer-side non-contact portion is an exposed portion where the core member is exposed.

1 . A hydraulic rotary machine comprising:
 a cylinder block to which a shaft is connected so as 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 of the piston;   a swash plate with which the shoe is in sliding contact;   a case accommodating the cylinder block; and   a valve plate formed by a core member and a resin layer coating the core member, the valve plate being provided with a supply port through which an operating liquid supplied to the volume chamber passes and a discharge port through which an operating liquid discharged from the volume chamber passes, the valve plate being interposed between the cylinder block and the case, wherein   the valve plate has
 a sliding contact portion formed by the resin layer, the cylinder block being in sliding contact with the sliding contact portion; and 
 a non-contact portion separated away from the cylinder block, and 
   at least a part of the non-contact portion is an exposed portion where the core member is exposed.   
     
     
         2 . The hydraulic rotary machine according to  claim 1 , wherein
 the supply port and the discharge port are defined by a port resin layer coating an inner peripheral surfaces of a supply base hole and a discharge base hole provided in the core member, respectively; and   the port resin layer is provided continuously to the sliding contact portion.   
     
     
         3 . The hydraulic rotary machine according to  claim 1 , wherein
 the non-contact portion has an outer-side non-contact portion provided closer to an outer side in a radial direction than the sliding contact portion; and   at least a part of the outer-side non-contact portion is the exposed portion.   
     
     
         4 . The hydraulic rotary machine according to  claim 1 , wherein
 the non-contact portion has an inner-side non-contact portion provided on an inner side in the radial direction of the sliding contact portion and formed with a gap from the cylinder block; and   at least a part of the inner-side non-contact portion is the exposed portion.   
     
     
         5 . The hydraulic rotary machine according to  claim 1 , wherein
 at least a part of the core member exposed in the exposed portion is a support portion supported in mold-forming of the resin layer.   
     
     
         6 . The hydraulic rotary machine according to  claim 5 , wherein
 the supply port and the discharge port are formed as arc-shaped grooves, respectively; and   the exposed portion which is the support portion is provided on at least one of an outer side in the radial direction and an inner side in the radial direction of an intermediate portion provided between the supply port and the discharge port in a circumferential direction.   
     
     
         7 . The hydraulic rotary machine according to  claim 1 , wherein
 the whole non-contact portion is formed as the exposed portion.   
     
     
         8 . A valve plate interposed between a cylinder block and a case in a hydraulic rotary machine, the valve plate being formed by a core member and a resin layer coating the core member, comprising:
 a sliding contact portion formed by the resin layer, the cylinder block being in sliding contact with the sliding contact portion; and   a non-contact portion separated away from the cylinder block, wherein   at least a part of the non-contact portion is the exposed portion where the core member is exposed.