EP3389926B1 - Grinding body having reduced weight - Google Patents

Description

The present invention relates, in various aspects, to a abrasive backing, a use of a abrasive backing, and a method of making a abrasive backing.

Different grinding base bodies are known from the prior art. Abrasive bases can be used to machine different objects. For this purpose, an abrasive is applied to the abrasive base. After wear of the abrasive this can be exchanged and the grinding base again be used. However, the prior art abrasive bodies have a comparatively high weight. On the one hand, this results in a high price of the abrasive base body. On the other hand, the handling of the abrasive base body is more expensive due to the high weight.

To counteract this, it is already known from the prior art to use a fiber-plastic composite (FKV) for the abrasive base body. For example, the Japanese publication describes JP11028668 A a grinding wheel, which has a core of several layered plate-shaped layers of a fiber-plastic composite. A grinding wheel section is glued to the core. The core also has flange portions on its side surfaces, via which the core can be attached to a shaft. As a result, this should be achieved a low weight, so that a high speed can be achieved during grinding.

Furthermore, the document is known from the prior art WO 2007/033396 A1 discloses a sanding base body with a carrier body for a rotating grinding or cutting tool, wherein the carrier body consists of a fiber-plastic composite with a peripheral wall, side walls and a hub. The document forms the preamble of claim 1.

However, it is still problematic that even such grinding wheels continue to have a comparatively high weight, which furthermore results in cost-intensive production and complicated handling.

Starting from this prior art, the invention therefore has the object of specifying a sanding base body, a use of a sanding base body and a method for producing a sanding base body, wherein a cost-effective production can be achieved with low weight.

The object is achieved by the provision of a sanding base according to claim 1.

It has been recognized that a mass-reduced abrasive base body can be provided by the inventive structure of the abrasive body of outer body, inner body and connecting structure in combination with the use of fiber-plastic composite materials. This is attributed to the fact that the structure according to the invention in combination with the choice of material according to the invention makes it possible to achieve an extremely force-flow-oriented, stiffness-optimized and strength-optimized structure which can serve as a carrier for the abrasive. Thus, the rotational mass and thus also the centrifugal forces occurring in the processing process of grinding can be reduced. In addition, higher accelerations of the abrasive body and improved balance options can be achieved.

By the substantially cylindrical outer body may advantageously be added to the abrasive. The abrasive may, for example, on the outside of the outer body (releasably) attached, in particular glued to this. Due to the substantially cylindrical outer body can thus a sufficient contact surface for the abrasive and thus a sufficiently large grinding surface can be provided.

Through the inner body, a connection can be achieved, in particular via its inner side, to a drive. The connection can be direct or indirect. For example, the inner body of the connection to a drive shaft.

In this case, material can be saved within the outer body by no solid abrasive base body, but a connection structure is provided. The connection structure is used for the mechanical transmission of force, in particular the torque transmission from the inner body to the outer body. The connection structure can be designed differently, provided that it allows a mechanical power transmission. The connection structure preferably extends from the inside of the outer body to the outer side of the inner body. Preferably, the connecting structure is substantially perpendicular to the inside of the outer body and substantially perpendicular to the outside of the inner body.

It has proven particularly advantageous if both the outer body and the inner body and the connecting structure consist of a fiber-plastic composite. For example, the outer body, the inner body and the connecting structure of the same fiber-plastic composite. However, it is also possible that for the outer body, the inner body and the connection structure different fiber-plastic composite materials (such as another fiber or another plastic matrix) are used.

According to the invention, the inner body is a substantially cylindrical inner body. By a substantially cylindrical inner body can over the inside of the Inner body is provided an advantageous surface for connection to a drive. The substantially cylindrical inner body and the substantially cylindrical outer body are preferably arranged concentrically to one another.

The inside of the inner body is preferably formed tapered along its cylinder axis. In this way, a secure connection can be made for example with a drive shaft.

According to an exemplary embodiment of the abrasive body according to the first aspect, the fibers of the fiber-plastic composite of the outer body, the inner body and / or the connecting structure as a scrim, fabric, braid, fabric and / or winding structure are formed. Preferably, the fibers of the fiber-plastic composite of both the outer body, as well as the inner body and the connecting structure are formed as described. Due to the described embodiments of the fiber-plastic composite and the fiber orientation resulting therefrom, the occurring rotational forces, the acting moments and the stiffness requirements of the abrasive base body can advantageously be taken into account. As a result, further mass reduction of the abrasive base body can be achieved with high rigidity.

According to an exemplary embodiment of the abrasive base body according to the first aspect, the fibers of the fiber-plastic composite of the outer body and / or the inner body are at least partially oriented in the circumferential direction of the respective body. This can advantageously increase the bending and torsional strength of the abrasive body. In particular, it has been found that in this context a fiber-plastic composite with braided or wound fibers is advantageous.

According to an exemplary embodiment of the abrasive base body according to the first aspect, the fibers of the fiber-plastic composite of the outer body, the Inner body and / or the connection structure at least partially oriented along the surface of the respective body. By means of such a fiber orientation, a further advantageous stability and strength of the abrasive base body can be achieved so that the mass of the abrasive base body can be further reduced.

According to an exemplary embodiment of the abrasive base body according to the first aspect of the fiber-plastic composite of the outer body, the inner body and / or the connecting structure is constructed in one or more layers. In particular, by a multi-layer structure of the respective fiber-composite plastic, a claimed layer structure of the abrasive base body can be achieved, since thereby the rotational forces, the acting moments and the stiffness requirements can be taken into account and as a result a loop body can be provided with low mass ,

According to an exemplary embodiment of the abrasive base body according to the first aspect, the connecting structure is formed as a flat, in particular disk-shaped connecting element. A flat, disk-shaped connecting element may be formed, for example, as a flat disc arranged between the outer body and the inner body, which preferably extends substantially perpendicular to the cylinder axis of the outer body and of the inner body.

The abrasive base body can advantageously have a cover, in particular in this embodiment. The cover is preferably provided at one end of the abrasive base body, so that in any case the space between the outer body and the inner body is covered on one side. Thereby, an excessive accumulation of grinding dust between the outer body and inner body and connecting structure can be prevented.

According to an exemplary embodiment of the abrasive base body according to the first aspect, the connection structure has a quasi-isotropic layer structure. As a result, uniform properties of the connection structure, in particular with regard to stability and elasticity can be achieved. In particular, in the case of a disc-shaped connecting structure, it can be achieved that this behaves like a metallic material. As a result, a mass reduction with reliable mechanical properties can be achieved.

Under a quasi-isotropic layer structure is understood that in particular the elastic properties are invariant with respect to the rotation about the normal. However, different properties can be present perpendicular to the layer plane. The quasi-isotropic layer structure can basically be constructed by a different number of (for example unidirectional) layers. However, the quasi-isotropic layer structure preferably comprises at least three layers.

According to an exemplary embodiment of the abrasive base body according to the first aspect, the connecting structure comprises a plurality of spoke-like arranged elements. Preferably, the connecting structure consists of the spoke-like angoerdneten elements. The spoke-like arranged elements may be formed, for example, as struts. For example, the spoke-shaped elements extend in the radial direction between the inner body and the outer body. An advantage of such a design is in particular that an accumulation of grinding dust is counteracted from the outset, since it can escape between the spoke-like arranged elements.

According to an exemplary embodiment of the abrasive base body according to the first aspect, the spoke-like arranged elements each have a core of foam material. In this way, an additional weight reduction in the region of the connection structure can be achieved.

According to an exemplary embodiment of the abrasive base body according to the first aspect, the outer body, the inner body and / or the connecting structure are constructed from preforms. For example, carbon fiber preforms are used. Preforms are understood in particular to be preforms made of fibers, which are used to form the corresponding regions of the abrasive base body. For example, different separate preforms are used for the outer body, the inner body and the connection structure.

According to an exemplary embodiment of the abrasive base body according to the first aspect, the connection structure is bonded to the outer body and / or inner body in a material-locking and / or form-fitting manner. Preferably, the connection structure is bonded to the inner body as well as to the outer body in a material-locking and / or form-fitting manner. For example, the connection structure, the outer body and the inner body are made of separate preforms and connected to each other by infiltration with plastic.

According to an exemplary embodiment of the abrasive base body according to the first aspect, the fibers of the fiber-plastic composite of the outer body, the inner body and / or the connecting structure comprise inorganic and / or organic reinforcing fibers, in particular at least one of carbon fibers, glass fibers, basalt fibers and aramid fibers. With inorganic fibers such as glass fibers or basalt fibers, high temperature resistance and low cost can be advantageously achieved. With organic fibers, such as aramid fibers or carbon fibers, in particular a high degree of orientation of the fibers can be achieved.

According to an exemplary embodiment of the abrasive base body according to the first aspect, the matrix material of the fiber-plastic composite of the outer body, the inner body and / or the connecting structure comprises a thermoset or a thermoplastic. For thermosets are the relatively high thermomechanical Strength and low specific gravity advantageous, while thermoplastics, for example, a weldability is given.

According to an exemplary embodiment of the abrasive base body according to the first aspect, the abrasive base body comprises a metal bush arranged at least in sections within the inner body. By means of the metallic bush, it is possible with advantage to provide a sanding base body with a metallic hub element. By way of example, the metallic bush is essentially cylindrical. For example, the metallic bushing is designed to taper in the axial direction. The metallic socket can be connected to the inner body by means of a clamping seat, which can be achieved, for example, by shrinking the inner body onto the metallic bushing. As a result, by the disposed within the inner body metal bushing a sanding base body can be provided in hybrid construction, which allows a stable connection to the drive despite low weight.

According to the invention, the outer body has a greater axial extent than the inner body. In the case of an essentially cylindrical outer body or inner body, an axial extent is understood in particular to be the extent in the direction of the respective cylinder axis. This results in an asymmetrical design of the base abrasive body, which allows a shortened compared to the outer body inner body, without reducing the grinding surface. Thus, a further mass reduction can be achieved, which enables a reduction of the rotational mass and the centrifugal forces during machining and a higher acceleration. In addition, the drive shaft or tool spindle can be shortened, which reduces the levers and the acting moments.

According to an exemplary embodiment of the abrasive base body according to the first aspect, the abrasive base body further comprises a on the outer body applied abrasive. The abrasive is formed for example as abrasive coating or as abrasive elements. For example, the abrasive is applied annularly on the outside of the outer body, in particular glued by means of an adhesive layer.

According to a second aspect, the object mentioned at the outset is achieved by using a grinding base body according to the first aspect for the abrasive machining of metallic parts, in particular camshafts. In abrasive machining, especially the grinding of metallic parts, such as camshafts, large diameters and high speeds of the abrasive bodies are needed. Due to their properties, in particular their low mass, the abrasive base bodies according to the first aspect are particularly suitable for this purpose.

According to a third aspect, the object mentioned at the outset is achieved by a method according to claim 17 for producing a sanding base body, in particular according to the first aspect.

As already stated in relation to the first aspect, an advantageous construction and, as a result, a reduced-mass abrasive base body can be provided by the inventive structure in combination with the choice of material according to the invention an extremely force flow compatible, stiffness-optimized and strength-optimized abrasive base body can be achieved. As already stated is the Inner body formed as a substantially cylindrical inner body. The outer body, the inner body and the connecting structure can be formed one after the other or at the same time.

According to the invention, the outer body, the inner body and / or the connecting structure are formed by first placing fibers on a molding tool and then infiltrating the fibers with plastic. By using a mold, the structure and the geometry of the abrasive base body can be precisely determined, since the fibers can first be brought as preforms in the desired position and orientation. Subsequently, the fibers can be fixed by plastic infiltration and consolidation. The plastic infiltration can be overpressure assisted or vacuum assisted. In this way, in particular individual preforms can be connected to one another in a material-locking manner.

Alternatively or additionally, it is conceivable that the fibers are already pre-infiltrated applied to the molds, for example as a prepreg. The fibers are pre-impregnated, for example, with a reaction resin. The fibers can then be cured in particular under the action of pressure and temperature. According to an exemplary embodiment of the method according to the third aspect, the abrasive base body is removed from the mold after removal of the mold after infiltration. By infiltration in particular a cohesive connection between the outer body, the connecting structure and the inner body was achieved. After infiltration, therefore, the mold, which gives the fiber-plastic composite and thus the abrasive base body its shape, are removed.

According to the invention, the molding tool comprises separate molding tool sections for the outer body, the inner body and / or the connecting structure. This allows a simple manufacturing process. The molding tool sections are in particular separate parts which can be mounted on one another or connected to one another. For example, a mold section for the inner body, a mold section for the connection structure, and a mold section for the outer body are provided. In this way, the fibers, for example, as preforms first applied to the corresponding mold sections, for example, be wrapped around them. Subsequently, the mold sections can be mounted. Finally, the fibers can be infiltrated.

According to an exemplary embodiment of the method according to the third aspect, a metallic bush is arranged and fixed at least in sections within the inner body. In this way, a hybrid construction can be achieved, which allows a high stability of the abrasive body in the field of connection to the drive. For example, the inner body can be shrunk onto the metallic bushing by exploiting the geometric design or the different thermal expansion behavior of the metallic bushing and the inner body. Thus, a press fit of the metallic bushing can be achieved. With regard to further advantageous embodiments of the second and third aspects, reference is made in particular to the description of the first aspect and the advantages described there. Also, by the preceding or following description of embodiments of the different aspects, in particular advantageous embodiments of the respective other aspects are to be disclosed.

Further exemplary embodiments of the different aspects of the invention can be found in the following detailed description of exemplary embodiments of the present invention, in particular in conjunction with the figures.

However, the figures enclosed with the application are intended only for the purpose of clarification but not for determining the scope of protection of the invention. The accompanying drawings are not to scale and are merely intended to exemplify the general concept of the present invention. In particular, features included in the figures should by no means be considered as a necessary part of the present invention.

Fig. 1a,b

ein erstes Ausführungsbeispiel eines Schleif-Grundkörpers gemäß dem ersten Aspekt in einer Teilaufsicht und in einem Teillängsschnitt;

Fig. 2a,b

ein zweites Ausführungsbeispiel eines Schleif-Grundkörpers gemäß dem ersten Aspekt in einer Teilaufsicht und in einem Teillängsschnitt;

Fig. 3

eine schematische Darstellung eines vorteilhaften Faserverlaufs; und

Fig. 4a-d

eine schematische Darstellung eines Ausführungsbeispiels eines Herstellungsverfahrens gemäß dem dritten Aspekt.

The drawing shows in

Fig. 1a, b

a first embodiment of a grinding base according to the first aspect in a partial and a partial longitudinal section;

Fig. 2a, b

a second embodiment of a grinding base according to the first aspect in a partial and a partial longitudinal section;

Fig. 3

a schematic representation of an advantageous fiber profile; and

Fig. 4a-d

a schematic representation of an embodiment of a manufacturing method according to the third aspect.

Fig. 1 first shows a first embodiment of a grinding base body 1 according to the first aspect in partial supervision ( Fig. 1a ) and in partial longitudinal section ( Fig. 1b ).

The abrasive base body 1 comprises a substantially cylindrical outer body 2 for receiving an abrasive (not shown). The abrasive can be applied, for example, flat on the outside of the outer body 2. In addition, the sanding base body 1 comprises a substantially cylindrical inner body 4 for connecting the sanding base body 1 to a drive (not The outer body 2, the inner body 4 and the connecting structure 6 are all formed of a fiber-plastic composite, the fibers each having organic reinforcing fibers, in this case Carbon fibers are. Alternatively or additionally, however, it is also possible to use other fibers, such as glass fibers, basalt fibers or aramid fibers. The plastic or matrix material of the fiber-plastic composite may be a thermoset or a thermoplastic.

The connecting structure 6 is formed here from a plurality of radially outwardly extending spoke-like arranged struts, of which only two struts 6a, 6b are shown here. This has the advantage that due to the recesses a deposition of grinding dust on the connecting structure 6 can be reduced. The struts 6a, 6b, etc. may have a core of foam material to allow a particularly easy variant of the abrasive base body 1.

The connection structure 6 is in particular connected to the outer body 2 as well as to the inner body 4 in a materially bonded manner. This can be achieved in particular by means of a plastic infiltration.

The outer body 2 and the inner body 4 are arranged concentrically and have the common cylinder axis 8. The outer body 2 and the inner body 4 extend from the connecting structure 6 in each case in both directions substantially parallel to the axis 8. It can be seen that the Outer body 2 in comparison to the inner body 4 on one side has a greater axial extent or that the inner body 4 on one side has a correspondingly smaller axial extent. As a result of this asymmetrical design, a further reduction in mass is achieved, in particular, which makes it possible to reduce the rotational mass and the centrifugal forces during machining and thus to increase the acceleration.

The fibers of the fiber-plastic composite of the outer body 2, the inner body 4 and the connecting structure 6 are preferably formed as a scrim, fabric, braid, fabric and / or winding structure. In this case, the fiber-plastic composite of the outer body 2, the inner body 4 and the connecting structure 6 is preferably constructed in multiple layers. The fibers of the outer body 2, the inner body 4 and the connecting structure 4 are constructed from preforms.

Within the inner body 4, a metallic bush 10 is also arranged as a hub element, with which a shaft-hub connection can be made. The inner body 4 has been shrunk onto the metallic bushing 10, so that the metallic bushing 10 is fixed in the inner body 4 by means of a clamping fit. In this case, the inner body 4 and / or the metallic bushing 10 along the cylinder axis 8 is tapered.

Fig. 2 now shows a second embodiment of a grinding base body 1 'according to the first aspect in plan view (2a) and in the longitudinal section (2b). The second embodiment is similar to that in FIG Fig. 1 illustrated embodiment. In this respect, the comments on Fig. 1 referenced and the same reference numerals (in the case of spelled notation) are used. In the following, the differences will be discussed.

In the in Fig. 2 In particular, the connecting structure 6 'of the grinding base body 1' is designed differently. The connecting structure 6 'is formed in this case as a flat, disk-shaped connecting element 6'. In this case, the disk-shaped connecting structure 6 'has a quasi-isotropic layer structure, as a result of which the connecting structure 6' behaves in the plane similar to a metallic material.

The abrasive base body 1 'also has a cover 12'. The cover 12 'is provided at one end of the abrasive base body 1', so that the space between the Outer body 2 'and the inner body 4' is covered. Thereby, an excessive accumulation of grinding dust between the outer body 2 ', the inner body 1' and the disc-shaped connecting structure 6 'can be prevented.

Fig. 3 shows a schematic representation of an advantageous fiber profile of a grinding base body. The abrasive base can, for example, the abrasive base body 1 from Fig. 1 or the abrasive base 1 ' Fig. 2 be.

As indicated by the dashed lines, the fibers of the fiber-plastic composite of the outer body 2, 2 'and the inner body 4, 4' are at least partially oriented in the circumferential direction of the respective body. The fibers of the fiber-plastic composite of the outer body 2, 2 ', the inner body 4, 4' and the connecting structure 6, 6 'are at least partially oriented along the respective surface.

The Fig. 4a-d Now show a schematic representation of an embodiment of a manufacturing method according to the third aspect. In this case, the in Fig. 2 shown grinding base body 1 'produced. However, the illustrated manufacturing method is also transferable to the production of differently shaped abrasive base body, such as abrasive base body 1.

First, fibers 30 are applied as a disk-shaped preform to form the subsequent connecting structure 6, 6 'on a mold section 20 ( Fig. 4a ).

Subsequently, fibers 32 are applied as a preform to form the later inner body 4, 4 'on a cylindrical mold section 22 ( Fig. 4b ). The mold sections 20 and 22 can then be joined together.

Now, the tool sections 20, 22 are connected to a further cylindrical mold section 24. Consisting of the mold section The assembled tools 20 and 24, the fibers 34 are applied to form the later outer body 2, 2 'with a braiding process ( Fig. 4c ).

Subsequently, an enclosing outer tool (not shown) is mounted, which images the shape-negative, substantially cylindrical contour of the outer body 2, 2 'to be produced. The outer tool and the now inner tools 20, 22, 24 form the Werkzeugkavität for the fibers 30, 32, 34. Here, the cylindrical contour may also contain changes in diameter, so as to be able to apply stepped or stepped abrasive coatings without the remote outer contour of the consolidated fiber composite body must be made by machining (milling / turning).

Finally, the fibers 30, 32, 34 are infiltrated with plastic, so that the outer body 2, 2 ', the inner body 4, 4' and the connecting structure 6, 6 'are formed from a fiber-plastic composite. After infiltration and consolidation, the abrasive base 1 'can be removed from the mold by removing the individual mold sections 20, 22, 24 (FIG. Fig. 4d )

Claims (19)

1. Grinding base body

   - with a substantially cylindrical outer member (2, 2') for accepting an abrasive material,

   - with an inner member (4, 4') for attaching the grinding base body (1, 1') to a drive unit, and

   - with a connecting structure (6, 6') for mechanical force transmission between the outer member (2, 2') and the inner member (4, 4'),

   wherein the outer member (2, 2'), the inner member (4, 4') and/or the connecting structure (6, 6') are made at least in sections of a fiber-plastic composite and wherein the grinding base body is characterized in that the inner member (4, 4') is formed substantially cylindrically and the outer member (2, 2') has a larger axial extension than the inner member (4, 4').
2. Grinding base body according to Claim 1,
   wherein the fibers (30, 32, 34) of the fiber-plastic composite of the outer member (2, 2'), the inner member (4, 4') and/or the connecting structure (6, 6') are formed as a laid web, woven fabric, braiding, surface structure and/or winding structure.
3. Grinding base body according to one of Claims 1 and 2,
   wherein the fibers (30, 32, 34) of the fiber-plastic composite of the outer member (2, 2') and/or the inner member (4, 4') are oriented at least for a section in the circumferential direction of the respective member.
4. Grinding base body according to one of Claims 1 to 3,
   wherein the fibers of the fiber-plastic composite of the outer member (2, 2'), the inner member (4, 4') and/or the connecting structure (6, 6') are oriented at least partly along the surface of the respective member.
5. Grinding base body according to one of Claims 1 to 4,
   wherein the fiber-plastic composite of the outer member (2, 2'), the inner member (4, 4') and/or the connecting structure (6, 6') is built of one or more layers.
6. Grinding base body according to one of Claims 1 to 5,
   wherein the connecting structure (6, 6') is formed as a flat, connecting element (6').
7. Grinding base body according to one of Claims 1 to 6,
   wherein the connecting structure (6, 6') has a quasi-isotropic layer structure.
8. Grinding base body according to one of Claims 1 to 5,
   wherein the connecting structure (6, 6') comprises several elements (6a, 6b) in spokelike arrangement.
9. Grinding base body according to Claim 8,
   wherein the spokelike arranged elements (6a, 6b) each comprise a core of foam material.
10. Grinding base body according to one of Claims 1 to 9,
    wherein the outer member (2, 2'), the inner member (4, 4') and/or the connecting structure (6, 6') are composed of preforms.
11. Grinding base body according to one of Claims 1 to 10,
    wherein the connecting structure (6, 6') is attached by integral bonding and/or by form fit to the outer member (2, 2') and/or inner member (4, 4').
12. Grinding base body according to one of Claims 1 to 11,
    wherein the fibers (30, 32, 34) of the fiber-plastic composite of the outer member (2, 2'), the inner member (4, 4') and/or the connecting structure (6, 6') comprise inorganic and/or organic reinforcing fibers (30, 32, 34).
13. Grinding base body according to one of Claims 1 to 12,
    wherein the matrix material of the fiber-plastic composite of the outer member (2, 2'), the inner member (4, 4') and/or the connecting structure (6, 6') comprises a thermoset or a thermoplastic.
14. Grinding base body according to one of Claims 1 to 13,
    wherein the grinding base body (1, 1') comprises a metal bushing (10, 10') arranged at least for a section inside the inner member (4, 4').
15. Grinding base body according to one of Claims 1 to 14,
    wherein the grinding base body (1, 1') furthermore comprises an abrasive material applied to the outer member (2, 2').
16. Use of a grinding base body according to one of Claims 1 to 17 for the abrasive machining of metal parts.
17. Method for making a grinding base body, where the method involves:

    - forming of a substantially cylindrical outer member (2, 2') to receive an abrasive material,

    - forming of a substantially cylindrical inner member (4, 4') for attaching the grinding base body (1, 1') to a drive unit, wherein the outer member (2, 2') has a larger axial extension than the inner member (4, 4') and

    - forming of a connecting structure (6, 6') for the mechanical force transmission between the outer member (2, 2') and the inner member (4, 4'),

    - wherein the outer member (2, 2'), the inner member (4, 4') and/or the connecting structure (6, 6') are formed at least in sections of a fiber-plastic composite,

    - wherein the outer member (2, 2'), the inner member (4, 4') and/or the connecting structure (6, 6') are formed in that first of all fibers (30, 32, 34) are placed on a mould tool (20, 22, 24) and then the fibers (30, 32, 34) are infiltrated with plastic, and

    - wherein the mould tool (20, 22, 24) comprises separate mould tool sections (20, 22, 24) for the outer member (2, 2'), the inner member (4, 4') and/or the connecting structure (6, 6').
18. Method according to Claim 17,
    wherein the grinding base body (1, 1') after being infiltrated is stripped by being removed from the mould tool (20, 22, 24).
19. Method according to one of Claims 17 and 18,
    wherein a metal bushing (10, 10') is arranged and secured for at least a section inside the inner member (4, 4').

Images