Swash plate type hydraulic rotating machine

Abstract

A swash plate type hydraulic rotating machine includes: a rotating shaft; a valve plate; a swash plate; a cylinder block on the outside of the rotating shaft slidingly contacting the valve plate; cylinders provided in the cylinder block having axially movable pistons therein; shoes on a distal end of respective pistons; an annular keep plate between the swash plate and the cylinder block supporting the shoes having a plain bearing within the inner periphery of the keep plate, the plain bearing supporting the keep plate to push the keep plate toward the swash plate side; and set springs biasing the plain bearing and the cylinder block toward the opposite sides in the axial direction. The swash plate type hydraulic rotating machine is configured such that, when in an assembled state, a gap in the axial direction between the cylinder block and the plain bearing is 0 or a fine gap.

1 . A swash plate type hydraulic rotating machine comprising:
 a rotating shaft;   a valve plate and a swash plate facing each other and away from each other in an axial direction of the rotating shaft;   a cylinder block fitted to an outside of the rotating shaft between the valve plate and the swash plate, such that the cylinder block is slidingly in contact with the valve plate;   a plurality of cylinders provided in the cylinder block;   a plurality of pistons inserted in the respective cylinders, such that the pistons are movable in the axial direction in a reciprocating manner;   a plurality of shoes each connected to a distal end of a respective one of the pistons such that each shoe is movable in a rocking manner, wherein the distal end of each piston protrudes from a respective one of the cylinders toward the swash plate side;   an annular keep plate loosely fitted to the rotating shaft between the swash plate and the cylinder block, the keep plate holding the shoes;   a plain bearing provided between the keep plate and the cylinder block, the plain bearing supporting the keep plate; and   spring members provided between the plain bearing and the cylinder block, the spring members biasing the plain bearing to cause the plain bearing to push the keep plate toward the swash plate side, wherein   a gap in the axial direction between the plain bearing the cylinder block is 0 or a fine gap when the swash plate type hydraulic rotating machine is in an assembled state.   
     
     
         2 . The swash plate type hydraulic rotating machine according to  claim 1 , wherein the gap has a size of 0, or has a size of more than 0 and equal to or less than 1.2 mm. 
     
     
         3 . A swash plate type hydraulic rotating machine comprising:
 a rotating shaft;   a valve plate and a swash plate facing each other and away from each other in an axial direction of the rotating shaft;   a cylinder block fitted to an outside of the rotating shaft between the valve plate and the swash plate, such that the cylinder block is slidingly in contact with the valve plate;   a plurality of cylinders provided in the cylinder block;   a plurality of pistons inserted in the respective cylinders, such that the pistons are movable in the axial direction in a reciprocating manner;   a plurality of shoes each connected to a distal end of a respective one of the pistons such that each shoe is movable in a rocking manner, wherein the distal end of each piston protrudes from a respective one of the cylinders toward the swash plate side;   an annular keep plate loosely fitted to the rotating shaft between the swash plate and the cylinder block, the keep plate holding the shoes;   a plain bearing provided between the keep plate and the cylinder block, the plain bearing supporting the keep plate;   spring members provided between the plain bearing and the cylinder block, the spring members biasing the plain bearing to cause the plain bearing to push the keep plate toward the swash plate side; and   a filling member filling a gap in the axial direction between the plain bearing and the cylinder block.   
     
     
         4 . The swash plate type hydraulic rotating machine according to  claim 3 , wherein the filling member is at least one shim plate. 
     
     
         5 . The swash plate type hydraulic rotating machine according to  claim 3 , comprising a time-hardening or thermosetting filler between the filling member and one of the plain bearing and the cylinder block. 
     
     
         6 . The swash plate type hydraulic rotating machine according to  claim 3 , wherein the filling member is a press-fit bushing.