EP1395397A2

EP1395397A2 - Grinding wheel, intermediate product and method for producing a grinding wheel of this type

Info

Publication number: EP1395397A2
Application number: EP02762282A
Authority: EP
Inventors: Patrick Müller
Original assignee: Sia Abrasives Industries AG
Current assignee: Sia Abrasives Industries AG
Priority date: 2001-06-12
Filing date: 2002-06-06
Publication date: 2004-03-10
Also published as: EP1266724A1; AU2002328286A1; US20050000166A1; WO2002100598A3; WO2002100598A2

Abstract

The invention relates to a grinding wheel for grinding curved surface sections (O), which is essentially comprised of a supporting body (2, 12) and of a grinding means (3, 13, 23) that is placed on the supporting body. The supporting body (2, 12) has a peripheral surface (4) whose intersection with a radial plane (R) has a curvature. The grinding means (3, 13, 23) is situated on the supporting body (2, 12) at least in the area of the peripheral surface (4). The grinding means thus also has a curvature at the intersection with the radial plane (R) that essentially corresponds to the curvature of the peripheral surface (4).

Description

Grinding wheel, intermediate product and method for producing such a grinding wheel

The invention relates to a grinding wheel for grinding curved surface sections and an intermediate product and a method for producing such a grinding wheel with the features of the preamble of the independent claims.

Different types of grinding wheels are known. For grinding flat surfaces, flat disks are used, for example, on one or both sides of which abrasive is applied.

From US 5 722 881 it is known to apply grinding flaps to the outside of a disc-shaped carrier.

From EP 911 116 grinding wheels are known in which abrasives are arranged in segments overlapping one another on both surfaces.

These known grinding wheels are suitable for grinding essentially flat surfaces. In certain applications, however, it is desirable to grind radii, for example in the case of welds that connect flat parts to one another. Especially in applications where the requirements for hygiene are high or where corrosion is to be avoided, it is important that the surface of the weld seam is smooth, in particular that it has no depressions or pores. Such concavely curved surfaces are relatively difficult to grind with conventional grinding wheels.

It is therefore an object of the present invention to avoid the disadvantages of the known, in particular one To create grinding wheel that is suitable for grinding curved concave surfaces. The grinding wheel should be easy to manufacture and have a long service life.

According to the invention, these objects are achieved with a grinding wheel with the features of the characterizing part of claim 1.

The grinding wheel essentially consists of a support body and abrasive applied to the support body. In this context, abrasive means in particular a flexible flat carrier which is provided with abrasive, that is to say typically an abrasive belt or sections made from an abrasive belt or a flat grinding wheel. However, it is also conceivable to apply abrasives directly and without a carrier to the carrier body, in particular to bond abrasive material directly to the carrier body.

The grinding wheel can be rotated about an axis, for example by a grinding machine. The support body has a circumferential surface which at least partially has a convex curvature in section in a radial plane. A radial plane is a plane that runs through the axis of rotation. The abrasive is arranged on the support body at least in the area of the peripheral surface. The abrasive therefore also has a curvature in section with the radial plane which corresponds approximately to the curvature of the circumferential surface.

The grinding wheel according to the invention is approximately rotationally symmetrical. Of course, the outer surface of the support body has a curvature as seen in the U direction. Here and below, the curvature of the peripheral surface is understood to mean the curvature of the peripheral surface in a radial plane.

Because the support body is provided with a convex peripheral surface and the abrasives are applied to the support body at least in the region of the peripheral surface, concave surface sections can be ground in a simple manner.

Because, according to the invention, an abrasive is applied to a support body with a predetermined shape with a curvature, the shape of the abrasive is always precisely defined by the support body. Unlike bonded abrasives, in which the shape of the grinding surface can change over time due to abrasion of the abrasive, the curved grinding surface according to the invention remains defined over the life of the grinding wheel.

According to a first embodiment, the support body is designed as a ring. Designing the support body as a ring has various advantages. In this way, the supporting body can be manufactured with relatively little material. In addition, a support body designed as a ring can be easily attached to a grinding machine using a fastening device, as is described, for example, in EP 911 116.

In an alternative embodiment, the support body is designed as a disk. An advantage of this design is that the wheel can be attached directly to a grinding machine.

In a preferred embodiment, the abrasive is clamped onto the support body by means of a clamping device. The flat, flexible abrasive is made around the curvature of the of the supporting body curved and clamped laterally. With such a clamping device it is reliably ensured that the abrasive does not come loose even under high loads.

The clamping device can also be designed as a holder for fastening the grinding wheel to a grinding machine. The clamping device serves at the same time to hold the grinding wheel and to fasten the abrasive.

According to an alternative embodiment, the abrasive is glued to the support body. Gluing is easier compared to jamming, since a specific clamping device can be dispensed with. Of course, gluing can also be combined with jamming. For this purpose, the abrasive is glued to the support body in a first step. To increase the resistance, the abrasive is also clamped at the same time.

In a further exemplary embodiment, the abrasive is formed from segments which are arranged next to one another on the supporting body in an overlapping manner in the circumferential direction. Similar to EP 911 116, the abrasive is fastened on one side of a support body. In contrast to EP 911 116, however, the carrier body has a curved outer surface over which the abrasive is applied in a curved manner. Individual segments can be particularly easily adapted to the curvature of the peripheral surface.

The segments are particularly advantageously almond-shaped. In this context, almond-shaped means that the segments have rounded side edges that taper towards the two ends of the segments. This shape reduces the Thickening of the layer consisting of the segments due to the overlap.

According to an alternative exemplary embodiment, the abrasive is designed as a band which, seen in the circumferential direction, is wound in windings on the support body which is designed as a ring. This type of attachment is particularly advantageous because, to a certain extent, the tape attaches itself to the carrier due to the windings. Since only a one-piece abrasive is applied, the manufacturing effort is reduced.

The overlap of the segments or the windings is advantageously designed such that the distance of the front end of the segments or windings from the axis of rotation, as seen in the direction of rotation, is greater than the distance of the rear end. Such an overlap leads to an advantageous self-renewal effect and thereby to an increase in the service life. During operation, the outermost rear end of the segments or windings is removed first.

According to a further exemplary embodiment, the abrasive is designed as a belt, which is applied to the circumferential surface when viewed in the circumferential direction. The tape is applied as a closed tape to the peripheral surface and bent along its side edges against the surfaces of the support body. The advantage of this embodiment is that, in contrast to overlaps, the grinding surface is essentially flat, that is to say has no steps.

In order to facilitate the folding over of the edges of the closed band, the band can be provided with incisions or cutouts along its edges. The segments formed between incisions or cutouts can be on the surfaces of the Support body are folded and overlap slightly. This prevents curling of the flat abrasive.

According to a further exemplary embodiment, the abrasive in the form of an abrasive material (abrasive grain) is bonded directly to the surface of the support body with a binder. It is therefore not necessary to attach and deform abrasives on a substrate.

The radius of curvature of the peripheral surface is typically adapted to the curved surface to be ground. The radius is preferably between 3 mm and 8 mm. The support body of the grinding wheel is advantageously made of glass fiber reinforced plastic. The abrasive can be stuck particularly permanently on such a support body. But it is also conceivable for the supporting body, in particular a supporting body designed as a ring, e.g. to be made of aluminum or plastic. The curved section of the circumferential surface of the support body advantageously extends over an angle of more than 180 °, that is to say the support body has an annular outer circumference. This provides a particularly large, actively usable grinding surface.

The invention is explained in more detail below in exemplary embodiments and with reference to the drawings. Show it:

1 shows a section through a surface to be ground and through part of a grinding wheel according to the invention,

FIG. 2 top view of a first exemplary embodiment of a grinding wheel according to the invention, FIG. 3 cross section through the exemplary embodiment according to FIG. 2,

FIG. 4 shows an enlarged representation of abrasives according to the exemplary embodiment from FIG. 2,

FIG. 5 top view of a second exemplary embodiment of the invention,

FIG. 6 cross section through a grinding wheel according to the exemplary embodiment from FIG. 5,

FIG. 7 top view of an intermediate product for producing a grinding wheel according to the invention,

FIG. 8 cross section through part of the intermediate product according to FIG. 7 and a grinding wheel produced therefrom,

Figure 9 top view of a third embodiment of the grinding wheel according to the invention

Figure 10 top view of the abrasive for a grinding wheel according to the embodiment of Figures 9 and

Figure 11 cross section through a fourth embodiment of a grinding wheel.

Figure 1 shows schematically the use of an inventive grinding wheel 1 in cross section. The grinding wheel 1 serves for example for grinding radii into the surface 0 of a weld seam S, which for example joins two metal parts M1, M2.

A grinding wheel 1 is fastened rotatably about an axis A. The grinding wheel 1 has a support body which, according to the following exemplary embodiments, can be designed as a ring 2 or as a wheel 12. 1 shows a section through the grinding wheel 1 along a radial plane R (see FIG. 2). Radial planes are planes that run through axis A. The support body of the grinding wheel 1 has a peripheral surface 4. The peripheral surface 4 is the surface defining the circumference of the grinding wheel 1. The circumferential surface 4 is convexly curved on average with the radial plane R. In the area of the peripheral surface 4, the support body of the grinding wheel 1 is provided with an abrasive which, according to the following exemplary embodiments, can be designed as a segment or as a belt or as an abrasive grain applied to the support body with a binder. Due to the convex curvature of the circumferential surface 4, the abrasive applied to the circumferential surface 4, for example a segment 3, also acquires a convex shape. The radius can be ground into the surface O of the welding point S with the curved abrasive.

A first exemplary embodiment of the grinding wheel according to the invention is shown in FIGS. 2 to 4. FIG. 2 shows a top view of the grinding wheel 1. The grinding wheel 1 according to this exemplary embodiment has a support body designed as a ring 2. The ring 2 is made of aluminum, steel or nylon or of a glass fiber reinforced plastic. Along the outer circumferential surface 4, the ring 2 is convexly curved in a radial sectional plane R. On the ring 2 are adjacent, mutually overlapping segments elements 3 arranged from a flexible abrasive. Typically, abrasive segments with a carrier material made of fabric (cotton or polyester) are used, on which the desired abrasive grain is held with a binder. The segments 3 are glued to the bottom and top of the ring 2 with an adhesive, for example a polyurethane adhesive. In addition, the segments 3 are clamped by a clamping device (see Figure 3). The clamping device consists of an upper part 5 and a lower part 6, which are held together for example with screws 10 and thus clamp the ring 2 with the segments 3. The clamping device consisting of parts 5, 6 can also be provided with a holding device 7 (shown in broken lines) by means of which the grinding wheel 1 can be attached to a grinding machine (not shown).

The overlap of the segments 3 is selected such that the distance d of the front end 8 of the segments 3 in the direction of rotation D from the axis of rotation A of the grinding wheel 1 is less than the distance of the rear end 9 of the segment 3 as seen in the direction of rotation D from the axis of rotation A. This results in a gentler grinding effect. At the same time, the rear end 9 is removed during operation, so that the grinding wheel 1 renews itself.

As shown in FIG. 3, the circumferential surface 4 is provided with a radius of curvature r in a radial sectional plane R. The peripheral surface 4 need not run exactly along a circle, that is to say the radius of curvature of the peripheral surface is not constant. The radius of curvature r is selected depending on the type of grinding point to be treated. It is typically 3 mm to 8 mm. When the grinding wheel 1 is worn out, the clamping device consisting of the parts 5, 6 can be released and the ring 2 can be replaced. Thanks to the clamping device, it is not necessary to replace the holding device 7 connected to the clamping device 5, 6.

A preferred form of the segments 3 is shown in FIG. The segments 3 are almond-shaped. This means that the segments have the greatest width in a central region 15. The central region 15 lies against the ring 2 along a circumferential outer line 16. The segments 3 taper away from the center line 15, the front end 8 and the rear end 9 being curved. This shape of the segments 3 takes into account the desired curvature of the segments 3. The problem of thickening due to additional material in the area of the fastening of the segments 3 on the ring 2 is thereby prevented.

FIGS. 5 and 6 show an alternative exemplary embodiment of the grinding wheel 1 according to the invention. The support body is designed as a ring 2 as in FIGS. 2 to 4. In contrast to the previous exemplary embodiment, the abrasive is designed as a band 13 which is wound in windings 14 around the ring 2. Similar to the segments 3, the windings 14 are arranged such that the distance of the front end 8 of the windings from the rotational direction A, as viewed in the direction of rotation, is greater than the distance of the rear end 9 of the windings 14. An advantage of the winding is that not individual ones Segments need to be attached to the ring. It is not necessary to glue the abrasive to the ring 2. The clamping device shown in FIG. 6, consisting of an upper and a lower part 5, 6, serves to press the grinding belt 13 onto the ring 2. The ring 2 is on its top and bottom with a concave pressing area 17 provided. The parts 5, 6 press the grinding belt 13 into the concave region 17. This leads to a tension of the grinding belt 13 in the area of the curved peripheral surface 4.

FIG. 7 shows a plan view of an intermediate product of a grinding wheel which is constructed similarly to the exemplary embodiment according to FIGS. 2 to 4. In contrast to the exemplary embodiment according to FIGS. 2 to 4, according to FIG. 7 the support body is designed as a continuous disk 12. The disc 12 is made, for example, of glass fiber reinforced plastic. To produce a grinding wheel according to this exemplary embodiment, segments 3 are first glued to a surface of the wheel 12, so that an inner end 11a is glued to the surface and an outer end 11b of the segments projects so far beyond the circumferential outer line 16 of the wheel 12 (see cross section in FIG. 8) that the projecting end 11b is then curved downward and can also be glued to the lower side 12 of the disk 12. The segment 3 assumes the convex shape of the peripheral surface 4.

Of course, the manufacturing method illustrated in this way can also be used to produce a grinding wheel according to FIGS. 2 to 4 with an annular support body.

Figures 9 and 10 show a further embodiment of the invention. Similar to the exemplary embodiment according to FIGS. 2 to 4, the support body is designed as a ring 2. The abrasive is designed as a band 23 which is applied to the ring 2 in the circumferential direction U along the circumferential outer line 16. The band 23 is flat in itself. So that the band 23 receives a curved surface, the edges 24 of the band 23 are on the upper or. Bottom of disc 2 folded and attached to it, for example glued and / or clamped. So that the band 23 does not curl when the edges 24 are folded over, the band is provided with incisions 25 extending from the edges 24 towards the center 26 of the band 23. On the upper or lower side of the disc 2, the band 23 overlaps in the area of the incisions 25 (see FIG. 9). FIG. 10 shows a section of the band 23 in a top view. The center 26 of the band is placed on the disc 2 along the circumferential outer line 16. Cutouts 25 are shown in FIG. Depending on the degree of curvature, the size of the cutouts 25 can be selected accordingly. Incisions are also conceivable in which no material is removed from the band 23. The exemplary embodiment according to FIGS. 9 and 10 can be realized both with a support body as a ring 2 and with a disk-shaped support body 12. The sanding belt 23 is a conventional sanding belt. The grinding belt can be glued along the circumferential outer line 16 and on the upper or lower side of the support body and / or clamped in place using a clamping device similar to that shown in the previous exemplary embodiments.

Figure 11 shows a cross section through a fourth embodiment of the invention. A support body designed as a ring 2 is designed as an injection molded part, in which the ends 11a, 11b of the segments 3 are anchored. Such anchoring is of course also conceivable in connection with a continuous disc according to the exemplary embodiment in FIGS. 7 and 8, and with a tape applied in the circumferential direction according to FIGS. 9 and 10. The parts of the fastening device 5, 6 for all of the exemplary embodiments shown can be manufactured, for example, from aluminum. Plastic injection molded parts are also conceivable. 1, 3, 6 and 11, the curved peripheral surface extends over an angle of more than 180 °. This means that a circumferential section of at least 180 ° can be used for grinding. The support body has an area of greatest thickness in the axial direction. The thickness of the supporting body decreases radially inwards from this area, so that a drop-shaped cross section results. The abrasive is applied radially inward beyond the area of greatest thickness on the carrier body.

According to a further exemplary embodiment, not shown in the figures, the abrasive is applied directly to the supporting body, for example a ring as shown in FIGS. 2 and 3, without a substrate. For this purpose, abrasive grains with a binder (e.g. epoxy resin) are applied to the surface of ring 2 e.g. (made of aluminum, steel or plastic).

Claims

claims

1. grinding wheel (1) for grinding curved surface sections (O),

with a supporting body (2, 12) and abrasive (3, 13, 23) applied to the supporting body

characterized in that the carrier body (2, 12) has a circumferential surface (4) which at least partially has a convex curvature in section in a radial plane (R) and that the abrasive (3, 13, 23) at least in the region of the circumferential surface ( 4) is arranged on the support body (2, 12) so that the abrasive has a curvature in section with the radial plane (R) which corresponds approximately to the curvature of the peripheral surface (4).

2. Grinding wheel according to claim 1, characterized in that the supporting body is designed as a ring (2).

3. Grinding wheel according to claim 1, characterized in that the supporting body is designed as a wheel (12).

4. Grinding wheel according to one of claims 1 to 3, characterized in that the grinding means (3, 13, 23) by means of a clamping device (5, 6) on the support body (2, 12) is clamped.

5. Grinding wheel according to claim 4, characterized in that the clamping device (5, 6) is provided with a holder (7) for fastening the grinding wheel (1) to a grinding machine.

6. Grinding wheel according to one of claims 1 to 5, characterized in that the abrasive (3, 13, 23) is glued to the support body (2, 12).

7. Grinding wheel according to one of claims 1 to 6, characterized in that the abrasive consists of segments (3) which are preferably arranged overlapping in the circumferential direction (U) on the support body (2, 12).

8. Grinding wheel according to claim 7, characterized in that the segments (3) are almond-shaped.

9. Grinding wheel according to claim 2 and one of claims 4 or 5, characterized in that the abrasive is designed as a band (13), seen in the circumferential direction (U) preferably overlapping in windings (14) on the ring

(2) is wound up.

10. Grinding wheel according to one of claims 7 to 9, characterized in that the overlap is formed such that the distance (d) of the front end in the direction of rotation (D)

(8) of the segments (3) or the windings (14) from the axis of rotation (A) is less than the distance of the rear end (9) in the direction of rotation (D) from the axis of rotation (A).

11. Grinding wheel according to one of claims 1 to 6, characterized in that the abrasive is designed as a belt (23) which, seen in the circumferential direction (U), at least on a circumferential outer line (16) of the circumferential surface (4) on the support body (2, 12) is applied.

12. Grinding wheel according to claim 11, characterized in that the band (23) along its edges (24) is provided with incisions or cutouts (25).

13. Grinding wheel according to one of claims 1 to 12, characterized in that the peripheral surface (4) has a radius of curvature (r) of 3 mm to 8 mm.

14. Grinding wheel according to one of claims 1 to 13, characterized in that the carrier (2, 12) consists of glass fiber reinforced plastic.

15. Intermediate product for producing a grinding wheel according to one of claims 7, 8, 10, 13 or 14, characterized in that the segments (3) are fastened with an inner end (11a) on the support body (2, 12) and that outer end (11b) of the segments (3) protrudes beyond the circumferential outer line of the support body (2, 12).

16. A method for producing a grinding wheel according to one of claims 7, 8, 10, 13 or 14, characterized by the steps

Providing an intermediate according to claim 15, bending the outer ends (11b) of the segments (3) around the curved peripheral portion (4),

Attach the outer ends (11b) to the support body (2, 12).