Method for Producing a Component Comprising a Position Measuring System

Abstract

A piston rod defining a surface and including a structure on the surface configured to be traced by a position sensor during a stroke of the piston rod. The surface, and consequently the structure, are covered by a coating by build-up welding. The structure is produced in the same operation during the build-up welding of the coating. The entire structure may be formed by the build-up welding, or a coded basic profile is incorporated before the build-up welding.

Claims

1. A method for applying a coating to a surface of a main body of a component and for producing a coated profile, the translatory movements of the coated profile being traceable by a position sensor, the method comprising: machining a coded basic profile in the surface of the main body; then forming a coating with a comparatively low iron content by build-up welding wherein the coded basic profile is changed to obtain said coated profile in such a way that the coded basic profile can still be traced by the position sensor in spite of the changes caused by the build-up welding; and then remelting and/or reworking the surface of the coating.

2. The method according to claim 1, further comprising: performing the build-up welding with a laser.

3. The method according to claim 2, further comprising: performing thermal imaging of molten material of the main body by way of a camera during the build-up welding; and setting a power supply of the laser in dependence on the thermal imaging.

4. The method according to claim 1, further comprising thereafter at least partially melting the coating.

5. The method according to claim 1, further comprising: producing the main body from a low-alloy steel.

6. A cylinder-piston arrangement comprising: a cylinder; a position sensor associated with the cylinder; and a piston rod at least partially located in the cylinder and defining a surface with a coating applied thereto according to the method of claim 1.

7. The cylinder-piston arrangement of claim 6, wherein: the piston rod is at least partially formed from a low-alloy steel, the position sensor is integrated in the cylinder, and the position sensor in conjunction with the structure based on the coded basic profile are configured for advanced error correction.

8. A method for applying a coating to a surface of a main body of a component and for producing a structure on the surface, the translatory movements of the structure being traceable by a position sensor, the method comprising: mechanically incorporating a coded basic profile having a geometry in the surface; then applying a coating to the surface by a build-up welding process using a laser; and adapting a size of a laser spot formed by the laser during the build-up welding process to the geometry of the coded basic profile.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Various exemplary embodiments of the disclosure are described in detail below with reference to the figures, in which:

[0033] FIG. 1 shows a first exemplary embodiment of a piston rod according to the disclosure after a first production step;

[0034] FIG. 2 shows the piston rod according to FIG. 1 after a second production step; and

[0035] FIG. 3 shows the piston rod according to FIGS. 1 and 2 after a third production step in the installed state.

DETAILED DESCRIPTION

[0036] FIG. 1 shows a detail of a main body 1 of a piston rod in a longitudinal section. The main body 1 was produced from a low-alloy steel. After that, a basic profile 3 was produced on a surface 2 of the piston rod or of the main body 1 in a machining process. The basic profile 3 has along the piston rod uniformly recurring, comparatively wide and flat grooves 4. Each groove 4 has a peripheral groove base 6 and two lateral peripheral flanks 8. Arranged between two flanks 8 is a web 10 of the surface 2. The axial extent of the groove bases 6 and of the webs 10 is the same. A groove 4 and a web 10 together have a radial extent of for example 100 mm. The grooves 4, and consequently the basic profile, have or has a depth T of for example 0.25 mm.

[0037] FIG. 2 shows the detail of the piston rod from FIG. 1 after a further production step. A coating 12 was provided on the surface 2 by build-up welding by means of a laser. This coating has a comparatively low iron content, in order to make later tracing of the surface 2 by a magnetic position sensor possible.

[0038] During the build-up welding of the coating 12, the basic profile 3 (compare FIG. 1) was attacked and changed, so that the grooves 4, the flanks 8 and the webs 10 of the basic profile 3 have now been overlaid with a structure 14 that is formed by radial elevations 16 and radial depressions 18.

[0039] FIG. 3 shows the piston rod after precision working of the surface 20 of the coating 12, the piston rod being accommodated in a guide of a cylinder 22. Integrated in the cylinder 22 is a position sensor 24. In this way, the Cylinder Integrated Measuring System (CIMS) is formed. An electronic evaluation unit (not shown any more specifically) is connected for signalling purposes to the position sensor 24 and is programmed in such a way that, in spite of the changes caused by the build-up welding, the position measuring system thus formed can detect the grooves 4 and webs 10 of the original basic profile 3 (cf. FIG. 1), and so can determine the position of the piston rod in relation to the cylinder 22.

[0040] A piston rod which has on its surface a structure that is traced by a position sensor during the stroke is disclosed. The surface, and consequently the structure, are covered by a coating by build-up welding. The structure is produced in the same operation during the build-up welding of the coating. The entire structure may be formed by the build-up welding, or a coded basic profile is incorporated before the build-up welding.

LIST OF DESIGNATIONS

[0041] 1 main body [0042] 2 surface [0043] 3 basic profile [0044] 4 groove [0045] 6 groove base [0046] 8 flank [0047] 10 web [0048] 12 coating [0049] 14 structure [0050] 16 radial elevation [0051] 18 radial depressions [0052] 20 surface [0053] 22 cylinder [0054] 24 position sensor [0055] T depth