Radial type hydraulic machine

Abstract

A radial type hydraulic machine, which prevents a cylinder block from bending, and does not cause imbalance in a radial direction of a pintle, is provided. For this purpose, a cylinder block ( 4 ) is supported at a casing to be relatively rotatable with respect to a pintle ( 3 ) provided to be incapable of rotating with respect to a casing ( 1 ). The cylinder block is connected to a rotating shaft ( 5 ) at one end portion, and both end portions of a cylinder bore section ( 6 ) are supported at the casing via bearings ( 7 ). Cancel ports ( 20 a , 20 b ) are formed at regions of both side portions of a low pressure port ( 16 ), to which a high pressure port ( 15 ) opposes, and pressure oil of the high pressure port can be introduced into them.

What is claimed is:  
     
         1 . A radial type hydraulic machine, comprising: 
 a pintle, which is supported at a casing of a radial type hydraulic machine to be incapable of rotating, and has a high pressure port and a low pressure port, and port passages communicating with said high pressure port and said low pressure port, respectively;    a cylinder block relatively rotatable with respect to said pintle; and    a cylinder bore section, which communicates with said high pressure port and said low pressure port by switching between them at the time of rotation of said cylinder block, and includes a plurality of cylinders,    wherein said cylinder block is supported via bearings at both sides with said cylinder bore section between them to be rotatable with respect to said casing, and one end of said cylinder block is connected to a rotating shaft of said radial type hydraulic machine; and    wherein cancel ports for balancing with a radial force from said high pressure port, which acts on said pintle, are formed at regions of said pintle, to which said high pressure port opposes, and pressure oil of said high pressure port is introduced into said cancel ports.    
     
     
         2 . The radial type hydraulic machine according to  claim 1 , 
 wherein said cancel ports are formed at both side regions of said low pressure port along a circumferential direction of said pintle each in a shape of a line of a narrow slit.    
     
     
         3 . The radial type hydraulic machine according to  claim 2 , 
 wherein the pressure oil of said high pressure port is introduced into said cancel ports, and each of hydrostatic bearing capacities on a port area by said cancel ports and a port area by said high pressure port is made equal.    
     
     
         4 . The radial type hydraulic machine according to  claim 3 , 
 wherein ports for low pressure each in a shape of a line of a narrow slit are formed at both side regions of said high pressure port along the circumferential direction of said pintle, which are the regions of said pintle to which said low pressure port opposes, and pressure oil of said low pressure port is introduced into said ports for low pressure.    
     
     
         5 . The radial type hydraulic machine according to  claim 4 , 
 wherein each of hydrostatic bearing capacities on a port area by said ports for low pressure and a port area by said low pressure port is made equal.    
     
     
         6 . The radial type hydraulic machine according to  claim 3 , 
 said radial type hydraulic machine being a radial type hydraulic machine having a plurality of rows of said cylinders in said cylinder bore section,    wherein said cancel ports are formed at regions to which said high pressure port in each row opposes in said pintle.    
     
     
         7 . The radial type hydraulic machine according to  claim 6 , 
 wherein ports for low pressure each in a shape of a line of a narrow slit are formed at both side regions of said high pressure port along the circumferential direction of said pintle in said each row, which are the regions of said pintle to which said low pressure port in said each row opposes, each of hydrostatic bearing capacities on a port area by said ports for low pressure and a port area by said low pressure port corresponding to said ports for low pressure is made equal, and pressure oil of said low pressure port is introduced into each of said ports for low pressure.    
     
     
         8 . The radial type hydraulic machine according to  claim 6 , 
 wherein said high pressure port in each row is evenly placed at a position in the circumferential direction of said pintle.