Piston of a hydraulic piston machine

Patent metadata

Field	Value
Publication number	US-11828274-B2
Application number	US-202318173132-A
Country	US
Kind code	B2
Filing date	Feb 23, 2023
Priority date	Mar 2, 2022
Publication date	Nov 28, 2023
Grant date	Nov 28, 2023

Abstract

A piston ( 1 ) having a piston shaft ( 2 ), a ball head ( 3 ) at one end of the piston shaft ( 2 ), and a slider shoe ( 4 ) mounted to the ball head ( 3 ), wherein the ball head ( 3 ) has a through channel ( 5 ), the slider shoe ( 4 ) has a sliding surface ( 6 ) and a through hole ( 7 ) in communication with an end of the through channel ( 5 ), and a plastic material ( 8 ) is arranged in a gap between the slider shoe ( 4 ) and the ball head ( 3 ) and forms an inner coating ( 9 ) of the through hole ( 7 ). The production of such a piston should be facilitated. To this end a sealing surface ( 14 ) is arranged at the end of the through channel ( 5 ) wherein the sealing surface ( 14 ) surrounds the opening of the through channel ( 5 ) into the through bore ( 7 ) and an inner diameter of the sealing surface ( 14 ) is smaller than an inner diameter of the inner coating ( 9 ) of the through bore ( 7 ).

First claim

What is claimed is:

1. A piston of a hydraulic piston machine comprising a piston shaft, a ball head at one end of the piston shaft, and a slider shoe mounted to the ball head, wherein the ball head comprises a through channel, the slider shoe comprises an end surface and a through bore in communication with an end of the through channel, and a plastic material is arranged in a gap between the slider shoe and the ball head and forms an inner coating of the through bore, wherein a sealing surface is arranged at the end of the through channel, wherein the sealing surface surrounds the opening of the through channel into the through bore and an inner diameter of the sealing surface is smaller than an inner diameter of the inner coating of the through bore.

2. The piston according to claim 1 , wherein the sealing surface is of truncated conical form.

3. The piston according to claim 1 , wherein the an outer diameter of the sealing surface is equal to or greater than an inner diameter of the inner coating.

4. The piston according to claim 1 , wherein the through channel comprises a first section of a reduced inner diameter, wherein the sealing surface is located at an end of the first section.

5. The piston according to claim 4 , wherein a second section of the through channel has the same inner diameter as the inner coating of the through bore.

6. The piston according to claim 1 , wherein the through bore comprises an inner radial recess and the inner coating extends into the inner radial recess.

7. The piston according to claim 6 , wherein the inner radial recess is located at the end surface of the slider shoe.

8. The piston according to claim 1 , wherein the slider shoe comprises a body, wherein the plastic material extends from the gap to an outer circumference of the body.

9. The piston according to claim 8 , wherein the plastic material covers a front face of the body facing the piston shaft.

10. The piston according to claim 8 , wherein the outer circumference of the body comprises an outer recess and the plastic material extends into the outer recess.

11. The piston according to claim 10 , wherein the outer recess is located at a diameter of the body which is larger than a diameter of the ball head.

12. The piston according to claim 8 , wherein the plastic material on the outer circumference of the body is machined at least on a face opposite the end surface.

13. The piston according to claim 1 , wherein the end surface comprises a sliding element made of a ceramic material.

14. The piston according to claim 13 , wherein the sliding element is in form of a ring.

15. The piston according to claim 1 , wherein the plastic material is rotatably fixed on the slider shoe.

16. The piston according to claim 2 , wherein the an outer diameter of the sealing surface is equal to or greater than an inner diameter of the inner coating.

17. The piston according to claim 2 , wherein the through channel comprises a first section of a reduced inner diameter, wherein the sealing surface is located at an end of the first section.

18. The piston according to claim 3 , wherein the through channel comprises a first section of a reduced inner diameter, wherein the sealing surface is located at an end of the first section.

Assignees

• Danfoss As

Inventors

• Andersen Stig Kildegaard
• Iversen Frank Holm
• Kolb Tommi

Classifications

• F04B1/126 Primary

  Piston shoe retaining means · CPC title

• F16J1/04

  Resilient guiding parts, e.g. skirts, particularly for trunk pistons · CPC title

• F16L27/04

  with partly-spherical engaging surfaces · CPC title

• F04B1/124

  Pistons · CPC title

• F03C1/0605

  Adaptations of pistons (pump pistons F04B1/124, F04B53/14) · CPC title