Piston guiding element, rock drilling machine and method

Patent metadata

Field	Value
Publication number	US-12330281-B2
Application number	US-202117928683-A
Country	US
Kind code	B2
Filing date	Jun 1, 2021
Priority date	Jun 1, 2020
Publication date	Jun 17, 2025
Grant date	Jun 17, 2025

Abstract

A piston guiding element, rock drilling machine and method for supporting a front end portion of a percussion piston of a rock drilling machine. The piston guiding element includes a braking recess at its rear end. The element further includes at least one bearing sleeve, which is provided with two axially successive slide bearing sections. Hydraulic fluid is conveyed between the slide bearing sections via a feed system.

First claim

The invention claimed is:

1. A piston guiding element arranged for providing support for a front end portion of a reciprocating percussion piston of a rock drilling machine, the element being a sleeve-like piece mountable inside a body of the rock drilling machine between the percussion piston and the body, the element comprising:
a first end, an opposed second end, an outer surface and an inner surface, wherein the first end is arranged to be facing towards an impact direction of the percussion piston, wherein the opposite second end is arranged to be facing towards a return direction of the percussion piston and is provided with a braking recess having a greater diameter on the inner surface, and the braking recess extending a first axial distance from the second end towards the first end, the inner surface of the element having a first groove, which is located at a second axial distance from the braking recess;
at least one radial opening located between a bottom of the first groove and the outer surface, the inner surface including a first axial section disposed between the braking recess and the first groove, and a second axial section disposed between the first groove and the first end; and
at least one separate bearing sleeve mounted inside the element and provided with the first and second axial sections, wherein at least the mentioned first and second axial sections are made of a slide bearing material, wherein the outer surface includes a second groove, the at least one radial opening extending to a bottom of the second groove, and wherein the outer surface includes at least one third groove extending from the second end to the second groove.

2. The element as claimed in claim 1 , wherein the bearing sleeve mounted inside the element is one single piece and is provided with the first and second axial sections.

3. The element as claimed in claim 1 , wherein the at least one separate bearing sleeve is made of the slide bearing material.

4. The element as claimed in claim 1 , wherein an inner surface of the at least one bearing sleeve includes at least one layer made of at least one slide bearing material.

5. The element as claimed in claim 1 , wherein the element comprises two separate bearing sleeves mounted successively inside the element, a first bearing sleeve being configured to form the first axial section, a second bearing sleeve being configured to form the second axial section, and the first groove being located between the first and second bearing sleeves.

6. The element as claimed in claim 1 , wherein an outer diameter at the second axial section between the second groove and the first end is greater than an outer diameter at the first axial section between the braking recess and the second groove, whereby the outer surface of the element has a stepped configuration.

7. A rock drilling machine, comprising:
a body;
an impact device including a percussion piston movable inside the body in a reciprocating manner in an impact direction and a return direction under influence of a pressurized hydraulic fluid alternating in working pressure chambers of the impact device; and
a piston guiding element in accordance with claim 1 arranged for supporting a front end portion of the percussion piston to the body, the piston guiding element including at least one slide bearing section and a braking recess for decelerating the percussion piston, wherein hydraulic fluid is conveyed between the slide bearing section and the braking recess, wherein the front end portion of the percussion piston is supported by means of the piston guiding element, the piston guiding element having two successive slide bearing sections, hydraulic fluid being conveyed between the two successive slide bearing sections.

8. The rock drilling machine as claimed in claim 7 , wherein a portion between the two successive slide bearing sections is connected to an impact pressure system of the impact device.

9. The element as claimed in claim 1 , wherein the outer surface includes at least one third groove extending from the second end to at least one radial opening.

10. The element as claimed in claim 9 , wherein the at least one third groove has a spiral configuration.

11. The element as claimed in claim 9 , wherein the at least one third groove has an axial configuration.

12. The element as claimed in claim 1 , wherein the at least one third groove has a spiral configuration.

13. The element as claimed in claim 1 , wherein the at least one third groove has an axial configuration.

14. A method of supporting a front end portion of a percussion piston of a rock drilling machine, the method comprising:
supporting the front end portion of the percussion piston on a body of the rock drilling machine by means of a sleeve-like piston guiding element including at least one slide bearing section and a braking recess for decelerating the percussion piston;
conveying hydraulic fluid between the slide bearing section and the braking recess;
providing the piston guiding element with at least one bearing sleeve;
supporting the percussion piston by means of two slide bearing sections and directing the hydraulic fluid flow between the two slide bearing sections; and
cooling the piston guiding element by the hydraulic fluid conveyed between the two slide bearing sections.

Assignees

• Sandvik Mining & Construction Oy

Inventors

• Koskimaki Antti
• Kandelin Lars
• Hamalainen Mikko
• Kela Timo
• Viinikka Matti
• Laakkola Esa

Classifications

• B25D2250/331

  Use of bearings · CPC title

• B25D2250/125

  Hydraulic tool components · CPC title

• B25D2217/0019

  Guide-sleeves · CPC title

• B25D9/12

  comprising a built-in liquid motor {, i.e. the tool being driven by hydraulic pressure} · CPC title

• E21B1/26

  by liquid pressure · CPC title