Hydraulic piston with a cooling and lubricating gasket valve

1. A hydraulic piston ( 1 ) comprising:

a cylindrical body ( 6 ) housed in a clearance in a cylinder ( 4 ),

said hydraulic piston ( 1 ) being translatable in said cylinder ( 4 ) with which said hydraulic piston ( 1 ) forms a hydraulic chamber ( 5 ) of a variable volume,

a first end of said hydraulic piston ( 1 ) having a compression surface ( 10 ) opening into the hydraulic chamber ( 5 ) for receiving pressure of a fluid ( 11 ),

a second end of said hydraulic piston ( 1 ) having a piston support surface ( 8 ) for exerting a force on a transmission means ( 9 ),

wherein said hydraulic piston ( 1 ) comprises:

at least one cooling and lubricating gasket valve ( 2 ) positioned on a side of the compression surface ( 10 ) and in an extension of the cylindrical body ( 6 ) with respect to which the at least one cooling and lubricating gasket valve ( 2 ) moves in longitudinal translation over a short stroke, said at least one cooling and lubricating gasket valve ( 2 ) comprising, first, a piston-side axial valve surface ( 23 ) which has a circular flow closure contact surface ( 24 ) which comes into contact with a valve contact surface ( 26 ) on the compression surface ( 10 ), said at least one cooling and lubricating gasket valve ( 2 ) having secondly an external cylindrical valve surface ( 14 ) which exposes a sealing means ( 16 ) which comes into contact with the cylinder ( 4 ) and remain sealed, said at least one cooling and lubricating gasket valve ( 2 ) comprising, third, a chamber-side axial valve surface ( 15 ) which faces the hydraulic chamber ( 5 );

at least one intermediate fluid outlet chamber ( 29 ) formed within the circular flow closure contact surface ( 24 ) by the piston-side axial valve surface ( 23 ) and the compression surface ( 10 );

at least one flow calibration opening ( 27 ) which passes through the at least one cooling and lubricating gasket valve ( 2 ) mainly through an axial direction, the hydraulic chamber ( 5 ) communicating with the at least one intermediate fluid outlet chamber ( 29 ) via said at least one flow calibration opening ( 27 );

at least one valve stop-link ( 3 ) which connects the at least one cooling and lubricating gasket valve ( 2 ) to the cylindrical body ( 6 ), said at least one valve stop-link ( 3 ) allowing said at least one cooling and lubricating gasket valve ( 2 ) to approach said cylindrical body ( 6 ) to a point that the circular flow closure contact surface ( 24 ) contacts the valve contact surface ( 26 ), while said at least one valve stop-link ( 3 ) prohibits said at least one cooling and lubricating gasket valve ( 2 ) from moving away from said cylindrical body ( 6 ) more than a certain distance; and

at least one valve return spring ( 30 ) which tends to move the at least one cooling and lubricating gasket valve ( 2 ) away from the cylindrical body ( 6 ).

2. The hydraulic piston according to claim 1 , wherein the at least one valve return spring ( 30 ) is wholly or partly housed within the at least one intermediate fluid outlet chamber ( 29 ).

3. The hydraulic piston according to claim 1 , wherein the sealing means ( 16 ) comprises at least one cutting segment ( 17 ) housed in a segment groove ( 18 ) provided in the at least one cooling and lubricating gasket valve ( 2 ) or added wholly or partly attached to said at least one cooling and lubricating gasket valve ( 2 ), said segment groove ( 18 ) opens at the external cylindrical value surface ( 14 ).

4. The hydraulic piston according to claim 1 , wherein the sealing means ( 16 ) comprises at least one flexible circular seal ( 19 ) housed in a segment groove ( 18 ) provided in the at least one cooling and lubricating gasket valve ( 2 ) or added wholly or partly attached to said at least one cooling and lubricating gasket valve ( 2 ), said segment groove ( 18 ) opens at the external cylindrical valve surface ( 14 ).

5. The hydraulic piston according to claim 1 , wherein the cylindrical body ( 6 ) has an anti-shearing release groove ( 20 ).

6. The hydraulic piston according to claim 1 , wherein a diameter of an axial end of the cylindrical body ( 6 ) situated on the side of the compression surface ( 10 ) gradually decreases over a certain length to form a lift relief ( 21 ).

7. The hydraulic piston according to claim 1 , wherein a diameter of an axial end of the cylinder ( 4 ) opposite the hydraulic chamber ( 5 ) gradually increases over a certain length to form a lift ( 12 ).

8. The hydraulic piston according to claim 1 , wherein the at least one valve link-stop ( 3 ) is constituted by a link-stop pin ( 13 ) which emerges integrally from the compression surface ( 10 ) in order to first pass through the at least one cooling and lubricating gasket valve ( 2 ) via a link-stop opening ( 22 ) provided in said at least one cooling and lubricating gasket valve ( 2 ) and, second, to project from the chamber-side axial valve surface ( 15 ) in order to expose to said chamber-side axial valve surface ( 15 ) a valve stop ( 28 ).

9. The hydraulic piston according to claim 8 , wherein the at least one flow calibration opening ( 27 ) comprises a clearance left between the external cylindrical valve surface ( 14 ) and the link-stop opening ( 22 ).

10. The hydraulic piston according to claim 1 , wherein the valve link-stop ( 3 ) is constituted by the valve link-stop extension ( 31 ) which emerges integrally with the piston-side axial valve surface ( 23 ), first, to penetrate into the cylindrical body ( 6 ) via a link-stop shaft ( 32 ) provided in said cylindrical body ( 6 ) and, second, to expose an extension stop ( 33 ) which works with a shaft stop ( 34 ) which is exposed by the link-stop shaft ( 32 ).

11. The hydraulic piston according to claim 10 , wherein the extension stop ( 33 ) comprises at least one flexible claw ( 42 ) that snaps into an abutment groove 43 forming the shaft stop 34 .

12. The hydraulic piston according to claim 10 , wherein the at least one valve return spring ( 30 ) is wholly or partly housed in an extender recess ( 44 ) arranged axially in the valve link-stop extension 31 .