Axial pistons hydraulic pump able to function in one or the other rotating direction

Abstract

A hydraulic pump able to function in one or the other rotating direction is of the type including a rotating barrel bearing pistons applied against a valve plate provided with two symmetrical opposed drillings. The valve plate provided with two symmetrical and opposed drillings, one connected to one of the output openings of the pump, the other one connected to the other output opening, is jointly linked to a double piston having two sections of equal surfaces, one of these surfaces being connected with one of the two output openings, the other one being connected with the other output opening so that valve plate is always applied against barrel bearing pistons by the discharge pressure in any rotating direction of the pump.

1 . An hydraulic pump able to function in one or the other rotating direction of the type comprising a rotating barrel bearing pistons applied against a valve plate provided with two symmetrical opposed drillings wherein said valve plate ( 80 ) provided with two symmetrical and opposed drillings ( 70 , 70 ′), one connected to one of the output openings ( 10 ) of the pump, the other one connected to the other output opening ( 11 ) is jointly linked to a double piston having two sections ( 81 , 82 ) of equal surfaces, one of these surfaces being connected with one of the two output openings ( 10 ), the other one being connected with the other output opening ( 11 ) so that the valve plate ( 80 ) is always applied against the rotating barrel ( 20 ) bearing the pistons ( 30 ) by the discharge pressure in any rotating direction of the pump. 
     
     
         2 . An hydraulic pump according to  claim 1  wherein the spherical heads of the pistons ( 30 ) are maintained applied against the inclined plane of the swash plate ( 40 ) by means of a disc ( 91 ) pressed by a spring ( 90 ) which is applying said barrel ( 20 ) against said valve plate ( 80 ). 
     
     
         3 . An hydraulic pump according to  claim 2  wherein said spring ( 90 ) is maintaining a back side of the barrel ( 20 ) against the valve plate ( 80 ). 
     
     
         4 . An hydraulic pump according to  claim 1  wherein said valve plate ( 80 ) is provided with two symmetrical drillings ( 70 , 70 ′). 
     
     
         5 . An hydraulic pump according to  claim 1  wherein the cubic displacement of the pump is lower than 5 cm3. 
     
     
         6 . An hydraulic pump according to  claim 2  wherein said valve plate ( 80 ) is provided with two symmetrical drillings ( 70 , 70 ′). 
     
     
         7 . An hydraulic pump according to  claim 3  wherein said valve plate ( 80 ) is provided with two symmetrical drillings ( 70 , 70 ′). 
     
     
         8 . An hydraulic pump according to  claim 2  wherein the cubic displacement of the pump is lower than 5 cm3. 
     
     
         9 . An hydraulic pump according to  claim 3  wherein the cubic displacement of the pump is lower than 5 cm3. 
     
     
         10 . An hydraulic pump according to  claim 4  wherein the cubic displacement of the pump is lower than 5 cm3.