Piston pump for delivering a fluid, and associated brake system

Patent metadata

Field	Value
Publication number	US-9303640-B2
Application number	US-68173708-A
Country	US
Kind code	B2
Filing date	Sep 18, 2008
Priority date	Oct 4, 2007
Publication date	Apr 5, 2016
Grant date	Apr 5, 2016

Abstract

A piston pump includes a piston assembly having at least one cross bore and a longitudinal bore corresponding to the at least one transverse bore, a cylinder, into which the piston assembly is guided in a longitudinally movable manner, and an inlet valve with a cage element, in which an inlet valve spring and an inlet valve sealing element are disposed, and a corresponding inlet valve seat, which is disposed on the piston assembly. Fluid flows through the longitudinal bore into a compression chamber via the inlet valve. A return spring is disposed in the compression chamber. The cage element has a resilient high-pressure sealing element that is configured to receive radially acting power components, and to effect a seal against a cylinder wall via a radial sealing surface, and in order to effect an axial seal against the piston assembly via an axial sealing surface.

First claim

The invention claimed is:

1. A piston pump, comprising:
a piston assembly, which includes a piston assembly wall, at least one transverse bore, and one longitudinal bore corresponding to the at least one transverse bore;
a cylinder, including a cylinder wall in which the piston assembly is guided longitudinally movably; and
an inlet valve, which includes a cage element in which an inlet valve spring and an inlet valve sealing element are disposed, and which includes a corresponding inlet valve seat, which is disposed on the piston assembly, wherein
the inlet valve sealing element is configured to be pressed sealingly by a spring force of the inlet valve spring into the corresponding inlet valve seat in order to close the longitudinal bore; and via the at least one transverse bore disposed in the piston assembly, fluid can be aspirated that can be conducted through the longitudinal bore via the inlet valve into a compression chamber in which a restoring spring for the piston assembly is disposed, and wherein
the cage element has an elastic high-pressure sealing element which absorbs radially acting force components and which seals off radially against the cylinder wall via a radial seal, the radial seal including:
a first radial sealing face having a full radial outside diameter including a substantially planar surface extending longitudinally along the entire longitudinal extent of the sealing element and configured for full surface contact with the cylinder wall along the entire longitudinal extent of the sealing element, and
a second radial sealing face having a full inside diameter including a substantially planar surface extending longitudinally and configured for full surface contact with the piston assembly wall,

the high-pressure sealing element further including:
an axial sealing face extending radially inward from said radial seal which seals off axially against the piston assembly, and
a radial contact region disposed toward the cylinder wall, the radial contact region being configured for receiving and centering an upper end winding of the restoring spring;

wherein said second radial sealing face extends longitudinally from said axial sealing face toward said piston assembly,
wherein said first radial sealing face extends longitudinally beyond said second radial sealing face, and
wherein the radial seal is configured to and formed of a material adapted to be widened radially between the first radial sealing face and the second radial sealing face, so that the first radial sealing face is in full surface contact with the cylinder wall and the second radial sealing face is in full surface contact with said piston assembly wall, at least partly by a longitudinal pressure acting on the high-pressure sealing element resulting from contact of the high-pressure sealing element with the piston assembly due to spring force of the restoring spring.

2. The piston pump as defined by claim 1 , wherein the piston assembly includes a first piston element and a second piston element, and the inlet valve seat comprises a wear-resistant material and is disposed on the second piston element, and the second piston element absorbs axially acting force components, and the at least one transverse bore corresponding with the longitudinal bore is made in the second piston element, and the elastic high-pressure sealing element seals off axially from the second piston element via the axial sealing face.

3. The piston pump as defined by claim 2 , wherein the first piston element is loosely coupled to the second piston element.

4. The piston pump as defined by claim 3 , wherein the first piston element is embodied as a cylindrical needle roll.

5. The piston pump as defined by claim 2 , wherein the first piston element is coupled to the second piston element by positive and/or nonpositive engagement.

6. The piston pump as defined by claim 5 , wherein the first piston element is embodied as a cylindrical needle roll.

7. The piston pump as defined by claim 1 , wherein the radial contact region is embodied as a radial receiving groove, which is shaped on the outer edge as a flexible sealing lip, which closes off the compression chamber in pressure-tight fashion toward the cylinder wall.

8. The piston pump as defined by claim 1 wherein the cage element, having the elastic high-pressure sealing element, and the piston assembly, having the inlet valve seat, are embodied as plastic injection-molded parts.

9. The piston pump as defined by claim 1 , wherein the cylinder wall defines a cylinder diameter and the piston assembly wall defines a piston diameter less than the cylinder diameter to define a longitudinal space extending longitudinally along the cylinder and between the cylinder wall and the piston assembly wall such that the radial seal completely fills at least a first portion of the longitudinal space when the first radial sealing face is in contact with the cylinder wall and the second radial sealing face is in contact with the piston assembly wall.

10. The piston pump as defined by claim 9 , wherein the radial seal extends along the longitudinal space a predetermined distance such that a second portion of the longitudinal space between the cylinder wall and the piston assembly wall is not filled by the radial seal.

11. The piston pump as defined by claim 10 , wherein the piston diameter of the piston assembly wall is the same along the first portion and the second portion.

12. The piston pump as defined by claim 1 , wherein the cylinder wall defines a cylinder diameter and the piston assembly wall defines a piston diameter less than the cylinder diameter to define a longitudinal space extending longitudinally along the cylinder and between the cylinder wall and the piston assembly wall such that the radial seal completely fills a first portion of the longitudinal space when the first radial sealing face is in contact with the cylinder wall and the second radial sealing face is in contact with the piston assembly wall; and the radial seal does not fill a second portion of the longitudinal space.

13. The piston pump as defined by claim 12 , wherein:
the radial contact region is in the form of a radial annular receiving groove; and
the upper end winding of the restoring spring is configured to be received within the radial annular receiving groove and an outer longitudinally disposed surface of the upper end winding is in full surface contact with the radial contact region.

Assignees

• Jahn Heiko
• Zimmermann Marc
• Bosch Gmbh Robert

Inventors

• Jahn Heiko
• Zimmermann Marc

Classifications

• F04B53/126

  Ball valves · CPC title

• F04B53/146

  Piston-rod guiding arrangements · CPC title

• F04B53/10 Primary

  Valves; Arrangement of valves · CPC title

• F04B1/0452

  Distribution members, e.g. valves (machines or pumps with cam-actuated distribution members at the outer ends of the cylinders F04B1/0472; machines or pumps with cam-actuated distribution members at the inner ends of the cylinders F04B1/0531; the piston-driving cams being provided with inlets and outlets F04B1/0535) · CPC title

• B60T8/4031

  Pump units characterised by their construction or mounting (pump units in combination with valve blocks B60T8/36) · CPC title