Piston unit and hydrostatic radial-piston machine

Patent metadata

Field	Value
Publication number	US-10082027-B2
Application number	US-201614994602-A
Country	US
Kind code	B2
Filing date	Jan 13, 2016
Priority date	Jan 13, 2015
Publication date	Sep 25, 2018
Grant date	Sep 25, 2018

Abstract

A piston unit includes a piston which has a rolling element seat configured to rotatably support a rolling element. The rolling element seat has a bearing surface with a surface coating composed of a polymer compound or with a ceramic surface coating.

First claim

What is claimed is:

1. A piston unit of a hydrostatic machine, comprising:
a piston including a rolling element seat configured to rotatably support a rolling element, the rolling element seat including a bearing surface,
wherein the bearing surface has a surface coating composed of a polymer compound,
wherein the polymer compound is applied in at least two layers, and
wherein the polymer compound in a first layer differs from the polymer compound in a second layer.

2. The piston unit as claimed in claim 1 , wherein the polymer compound has a layer thickness of approximately 40 to 80 μm.

3. The piston unit as claimed in claim 1 , wherein the polymer compound is a dispersion before it is applied.

4. The piston unit as claimed in claim 1 , wherein the surface coating is applied to the bearing surface in the form of an aerosol.

5. The piston unit as claimed in claim 1 , wherein the rolling element is supported directly on the bearing surface.

6. The piston unit as claimed in claim 1 , wherein the surface coating of the bearing surface extends so far in a longitudinal direction of the piston that the rolling element is at least partially supported in a radial direction of the piston.

7. A piston unit, of a hydrostatic machine, comprising:
a piston including a rolling element seat configured to rotatably support a rolling element, the rolling element seat including a bearing surface,
wherein the bearing surface has one of a surface coating composed of a polymer compound and a ceramic coating, and
wherein the bearing surface is integrally formed with the piston.

8. The piston unit as claimed in claim 7 , wherein the ceramic surface coating has a layer thickness of approximately 25 to 35 μm.

9. A hydrostatic radial-piston machine, comprising:
at least one piston unit including a piston, the piston having a rolling element seat configured to rotatably support a rolling element,
wherein the rolling element seat includes a bearing surface having a surface coating composed of a polymer compound,
wherein the polymer compound is applied in at least two layers,
wherein the polymer compound in a first layer differs from the polymer compound in a second layer, and
wherein the at least one piston unit is guided in a cylinder bore of a cylinder block.

10. The piston unit as claimed in claim 9 , wherein the polymer compound has a layer thickness of approximately 40 to 80 μm.

11. The piston unit as claimed in claim 9 , wherein the polymer compound is a dispersion before it is applied.

12. The piston unit as claimed in claim 9 , wherein the surface coating of the bearing surface extends so far in a longitudinal direction of the piston that the rolling element is at least partially supported in a radial direction of the piston.

Assignees

• Bosch Gmbh Robert

Inventors

• Macphee Adam
• Kermode Geoffrey
• Kilroy Kevin

Classifications

• F04B1/0408

  Pistons · CPC title

• F04B1/0474

  with two or more serially arranged radial piston-cylinder units · CPC title

• F01B1/0651

  consisting of several cylindrical elements, e.g. rollers · CPC title

• F01B1/0655

  cylinders · CPC title

• F04B1/107

  with actuating or actuated elements at the outer ends of the cylinders · CPC title