GRINDING WHEEL

Abstract

A grinding wheel includes an elastomerically deformable supporting layer, at least a first metallic surface fastened to the elastomerically deformable supporting layer, the metalic surface being an elastically deformable metal foil and includes abrasive particles attached to the at least one metalic surface. The particles may include at least one of: cubic boron nitride or diamonds. The metal foil may have a thickness of less than 1 mm. The abrasive particles may be bonded galvanically on the metallic surface. The abrasive particles may be bonded on the metalic surface in a plurality of areas having regions without abrasive particles therebetween. The metal foil may be adhesively bonded onto the elastomerically deformable supporting layer. The elastomerically deformable supporting layer may be plastic foam. The elastomerically deformable supporting layer may be adhesively bonded onto a metallic supporting body.

Claims

1. A grinding wheel, comprising: an elastomerically deformable supporting layer; at least a first metallic surface fastened to the elastomerically deformable supporting layer, the metalic surface being an elastically deformable metal foil; and abrasive particles attached to the at least one metalic surface.

2. The grinding wheel of claim 1, wherein the particles include at least one of: cubic boron nitride or diamonds.

3. The grinding wheel of claim 1, wherein the metal foil has a thickness of less than 1 mm.

4. The grinding wheel of claim 1, wherein the abrasive particles are bonded galvanically on the metallic surface.

5. The grinding wheel of claim 1, wherein the abrasive particles are bonded on the metalic surface in a plurality of areas having regions without abrasive particles therebetween.

6. The grinding wheel of claim 1, wherein the metal foil is adhesively bonded onto the elastomerically deformable supporting layer.

7. The grinding wheel of claim 1, wherein the elastomerically deformable supporting layer is plastic foam.

8. The grinding wheel of claim 1, wherein the elastomerically deformable supporting layer is adhesively bonded onto a metallic supporting body.

9. The grinding wheel of claim 1, further comprising: a second metallic surface fastened to an elastomerically deformable supporting layer, the second metalic surface being opposite to the first metallic surface and having abrasive particles attached thereto.

10. The grinding wheel of claim 9, wherein the particles attached to the second metallic surface include at least one of: cubic boron nitride or diamonds.

11. The grinding wheel of claim 1, wherein the elastically deformable metal foil extends over an outer annular region of the grinding wheel.

12. An apparatus for grinding rigid, metallic welding electrodes for resistance welding, the apparatus comprising: a grinding wheel having at least one elastomerically deformable supporting layer, a metallic surface fastened to the elastomerically deformable supporting layer, the metalic surface being an elastically deformable metal foil and abrasive particles attached to the at least one metalic surface; a bearing, fastened on a pivotable and displaceable bearing carrier, for rotatably mounting the grinding wheel about a rotational axis; a grinding wheel drive which is coupled to the grinding wheel to rotate the grinding wheel, wherein a bearing plane of the bearing is pivoted in relation to a starting plane and is displaced in a starting direction which is perpendicular with respect to the starting plane; and an apparatus for pivoting and displacing the bearing carrier, coupled to the bearing carrier, that causes the surface of the grinding wheel to produce a curved surface about a stationary reference point which is at a radial spacing from a center point of the grinding wheel.

13. The apparatus of claim 12, wherein the particles include at least one of: cubic boron nitride or diamonds.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The system described herein will be shown in greater detail in the following text with reference to the drawings, which are as follows:

[0025] FIGS. 1 to 4 show a perspective illustration and three sectional illustrations of the grinding wheel and a workpiece of the grinding apparatus which is described herein.

[0026] FIG. 5 shows a plan view of a first embodiment of the grinding wheel which is described herein.

[0027] FIG. 6 shows an illustration of the grinding wheel from FIG. 5, which illustration is sectioned along the sectional line A-A.

[0028] FIG. 7 shows the enlarged detail X from FIG. 6.

[0029] FIG. 8 shows a plan view of a second embodiment of the grinding wheel which is described herein.

[0030] FIG. 9 shows an illustration of the grinding wheel from FIG. 8, which illustration is sectioned along the sectional line B-B.

[0031] FIG. 10 shows the enlarged detail Y from FIG. 9.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

[0032] FIGS. 1 to 4 show the grinding process which is aimed for using the grinding apparatuses which are described in documents DE 10 2012 215 532 A1 and DE 10 2014 203 409 A1 and is preferably to be carried out using the grinding wheel 1 which is described herein. The grinding wheel 1 and the workpiece 2 are depicted here. The grinding wheel 1 is of planar configuration, that is to say it has two grinding surfaces which are parallel to one another. In the illustration which is shown, the workpiece 2 is a welding electrode made from copper. The welding electrode 2 is shown in a free-standing manner. In practice, it is moved to the grinding wheel 1 by a welding gun which is fastened to a robot arm. The grinding wheel 1 preferably consists of an elastic, possibly foamed plastic material, on the disk-shaped upper side and lower side of which abrasive grinding materials are deposited. Rigid grinding wheels 1 may also be used, however. The grinding wheel 1 is screwed fixedly on a hub 3 which can be pivoted and displaced by the present grinding apparatus.

[0033] The rotational axis of the bearing of the grinding wheel is provided with the reference numeral 4 in FIGS. 2 to 4. The bearing itself is not shown.

[0034] The vertical direction, along which the grinding wheel 1 can be displaced, is provided with the reference numeral 5 in FIGS. 2 to 4. The vertical direction 5 in FIGS. 2 to 4 corresponds to the starting direction. It is noted that the starting direction can be selected to be in any desired position. The workpiece 2 is then to be moved in the corresponding position onto the grinding face of the grinding wheel 1. The relative position of the components of the grinding apparatus is pivoted correspondingly in the case of pivoting of the starting direction 5.

[0035] It can be gathered from FIGS. 2 and 3, in particular, that the rotational axis of the mounting of the grinding wheel 1 can be pivoted with respect to the vertical starting direction 5 in order to produce a rotationally symmetrical, convex surface on the workpiece 2. Here, the rotational axis 4 can be pivoted not only in the illustrated plane of FIGS. 2, 3 and 4, but rather also perpendicularly with respect thereto and in any desired other directions. The grinding wheel 1 is held in such a way that the rotational axis 4 can be pivoted freely around the starting direction 5 within a conical adjustment region. At the same time, the grinding wheel 1 can be displaced in the vertical starting direction 5. The pivoting movements and displacement movements are synchronized in such a way that the grinding wheel 1 is in contact with the surface of the workpiece 2 in the vicinity of a reference point 6. As a result of the pivotability of the grinding wheel 1, the grinding wheel 1 can produce a convexly formed, in particular spherical or conical surface on the end side of the workpiece 2. During the machining process, the workpiece 2 remains stationary in relation to the machine frame of the grinding apparatus, with the result that the reference point 6 is stationary.

[0036] The reference point 6 is at a radial spacing from the center point of the grinding wheel 1. Due to the radial spacing, the pivoting of the grinding wheel 1 causes a movement of the reference point 6 in the starting direction 5, which movement is compensated for by way of a displacement of the mounting of the grinding wheel 1. The displacement movement and the pivoting movement of the grinding wheel 1 are synchronized in such a way that the surface of the grinding wheel 1 always makes contact with the workpiece 2 in the vicinity of the reference point 6. A tumbling movement of the grinding wheel 1 can thus be produced, which tumbling movement produces a convex surface on the end side of the workpiece 2 in the region of the reference point 6.

[0037] The surface of the workpiece 2 does not necessarily have to be ground in a rotationally symmetrical manner. Any desired forms of the end side of the workpiece 2 in the pivoting range and displacement range of the grinding wheel 1 can be realized by way of the free pivoting and displacement of the grinding wheel 1.

[0038] FIG. 5 shows a plan view of a first embodiment of a grinding wheel 1 of the type described herein. The grinding wheel 1 has a metal foil 8 in an annular outer region 7 which extends approximately over a third of the radius of the grinding wheel 1. The metal foil 8 can be seen on an enlarged scale in FIG. 7. Diamond particles 10 are bonded in circular areas 9 on the metal foil 8. The diamond particles are shown diagrammatically as triangular peaks in FIG. 7, although the contour of the edges of the diamond particles 10 differs in practice from a triangular contour. The bonding of the diamond particles 10 to the metal foil 8 takes place galvanically by way of nickel. Approximately 50% of the diamond particles protrude out of the nickel bond. It is also possible to bond other abrasive particles, for example cubic boron nitride CBN, galvanically on the metal foil 8.

[0039] The metal foil 8 is adhesively bonded on a middle, elastomeric supporting layer 11 comprising a closed-pore polyethylene foam. An opening 12 is situated in the center of the grinding wheel 1. The opening 12 serves to fasten the grinding wheel 1 to the hub 3 (see FIGS. 1-4).

[0040] On account of the elastomeric polyethylene foam, the metallic surface of the grinding wheel 1, which metallic surface is formed by way of the metal foil 8, can deflect flexibly at every location. The metal foil 8 is deformable to a certain extent. Hard shocks or jolts are cushioned on the surface of the grinding wheel 1 as a result of the deflection of the metal foil 8 with the diamond particles 10 which is adhesively bonded on the elastomeric supporting layer 11.

[0041] The grinding wheel 1 is provided for the purpose of machining welding electrodes 2 made from copper. After a few welding operations, the welding electrodes 2 have to be re-ground. Since no great quantities of material have to be removed, the corresponding forces on the grinding wheel 1 are only small and can be introduced directly into the hub 3 via the elastomeric supporting layer 11.

[0042] As an alternative to the embodiment from FIGS. 5 to 7, FIGS. 8 to 10 show a version of the grinding wheel 1, in which a supporting body 13 made from aluminum extends in the center of the grinding wheel 1 between its two surfaces. The supporting body forms a core of the grinding wheel 1. One thin, elastomeric supporting layer 11 is applied on each of the two outer sides of the metallic supporting body 13 in the annular region 7, in which the metal foil 8 is arranged. The thin elastomeric supporting layer 11 also consists of closed-pore polyethylene foam. It extends on each side of the metallic supporting body 13 over a thickness of from approximately 1 mm to 2 mm. The flexibility of the thin elastomeric supporting layer 11 is sufficient, in order to effectively absorb shocks which act on the surface of the grinding wheel 1 with the diamond particles 10 during the machining.

[0043] In FIGS. 8 to 10, parts which are identical to the embodiment of the grinding wheel 1 from FIGS. 5 to 7 are identified by identical reference numerals.

[0044] Other embodiments of the invention will be apparent to those skilled in the art from a consideration of the specification or practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims.