Plastic primary piston with insert for a tandem penetration-type master cylinder and a master cylinder equipped with such a piston

Patent metadata

Field	Value
Publication number	US-9581241-B2
Application number	US-201113996670-A
Country	US
Kind code	B2
Filing date	Nov 30, 2011
Priority date	Dec 21, 2010
Publication date	Feb 28, 2017
Grant date	Feb 28, 2017

Abstract

A primary piston of molded plastic material equipped with a metallic insert and having grooves, mounted in a master cylinder comprising at least a primary piston and a secondary piston mounted in the bore hole of the master cylinder. These pistons can create pressure, respectively, in a primary pressure chamber and in a secondary pressure chamber due to the action of a push rod on the primary piston.

First claim

The invention claimed is:

1. A primary piston for a tandem penetration-type brake master cylinder, comprising:
a primary piston of molded plastic material and having an overmolded stamped sheet-metal insert situated between a forward cavity and a cavity, and also having at least one groove on the surface emerging on a forward face;
wherein the metallic insert has at least one hole, and
wherein the hole is substantially parallel to the axis of the piston.

2. The primary piston of claim 1 , wherein the primary piston is made of a thermoset plastic material.

3. The primary piston of claim 1 , wherein, after injection of the plastic material, the hole of the insert forms a blind hole in the piston.

4. The primary piston of claim 1 , wherein the surface of the piston is ground by machine.

5. The primary piston of claim 1 , wherein the primary piston is made of plastic materials capable of damping noise.

6. A master cylinder, comprising:
a master cylinder arrangement: and
at least a primary piston and a secondary piston mounted in a bore hole of the master cylinder arrangement, wherein the primary piston is of molded plastic material and having a metallic insert situated between the forward cavity and the primary pressure chamber and in that it also has at least one groove on a surface emerging on the forward face,
wherein the metallic insert has at least one hole, and
wherein the hole is substantially parallel to the axis of the piston.

7. The master cylinder of claim 6 , wherein the insert of the primary piston is made of a magnetizable material, so that the piston emits a magnetic field capable of being detected by a magnetic field sensor.

8. The master cylinder of claim 6 , wherein the primary piston is made of a thermoset plastic material.

9. The master cylinder of claim 6 , wherein, after injection of the plastic material, the hole of the insert forms a blind hole in the piston.

10. The master cylinder of claim 6 , wherein the surface of the piston is ground by machine.

11. The master cylinder of claim 6 , wherein the primary piston is made of plastic materials capable of damping noise.

Assignees

• Lhuillier Laurent
• Grech Daniel
• Bernadat Olivier
• Rodriguez Marc
• Bosch Gmbh Robert

Inventors

• Lhuillier Laurent
• Grech Daniel
• Bernadat Olivier
• Rodriguez Marc

Classifications

• B60T11/236

  Piston sealing arrangements · CPC title

• F16J1/01 Primary

  characterised by the use of particular materials (F16J1/02 takes precedence) · CPC title

• B60T11/232 Primary

  Recuperation valves · CPC title