Grinding Disc Device for a Grinding Apparatus

Abstract

A grinding disc device for a grinding apparatus is described, having at least one grinding layer and a carrier disc fixedly connected to the grinding layer. The grinding layer has at least one connection surface (F.sub.V) connected to the carrier disc and forms an abrasive grinding surface (F.sub.S) lying opposite the connection surface (F.sub.V) and facing away from the carrier disc. The carrier disc made of a plastic material is produced by injection molding and is connected immediately and directly to the connection surface (F.sub.V) of the grinding layer, wherein the plastic material of the carrier disc is sprayed by injection molding immediately and directly onto the connection surface (F.sub.V) of the grinding layer, such that the carrier disc and the grinding layer are connected to one another in a material-locking manner.

Claims

1. A grinding disc device for a grinding apparatus comprising: at least one grinding layer and a carrier disc fixedly connected to the grinding layer, wherein the grinding layer comprises a connection surface (F.sub.V) connected to the carrier disc and forms an abrasive grinding surface (F.sub.S) lying opposite the connection surface (F.sub.V) and facing away from the carrier disc, wherein the carrier disc is made of a plastic material produced by injection molding and is connected immediately and directly to the connection surface (F.sub.V) of the grinding layer, wherein the plastic material of the carrier disc is sprayed by means of injection molding immediately and directly onto the connection surface (F.sub.V) of the grinding layer, such that the carrier disc and the grinding layer are connected to one another in a materially-bonded manner.

2. The grinding disc device according to claim 1, wherein the grinding layer consists essentially of a flat, circular grinding disc or a sanding disc.

3. The grinding disc device according to claim 1, wherein the grinding layer is formed by a fiber disc or a vulcanised fiber disc.

4. The grinding disc device according to claim 1, wherein the grinding layer is composed of grinding lamellas.

5. The grinding disc device according to claim 1, wherein the connection surface (F.sub.V) and the grinding surface (F.sub.S) lying opposite the connection surface (F.sub.V) are each constituted as essentially continuous, annular surfaces.

6. The grinding disc device according to claim 1, wherein the grinding surface (F.sub.S) is formed by a ceramic grain abrasive medium scattered on a carrier material.

7. The grinding disc device according to any claim 1, wherein the grinding surface (F.sub.S) of the grinding layer connected to the carrier disc is constituted dish-shaped.

8. The grinding disc device according to claim 1, wherein cooling air slots are formed in the carrier disc distributed over a periphery of the carrier disc for passage of cooling air.

9. The grinding disc device according to claim 1, wherein the carrier disc is constituted in one piece with a hub part, wherein ventilation ribs extend radially outwards from the hub part.

10. The grinding disc device according to claim 9, wherein the hub part comprises an inner thread for the fastening of the grinding disc device on a drive shaft of the grinding apparatus.

11. The grinding disc device according to claim 9, wherein cooling air passage slots are also formed into the hub part.

12. The grinding disc device according to claim 1, wherein the carrier disc is produced from a thermoplastic polymer.

13. The grinding disc device according to claim 12, wherein the carrier disc is made from a thermoplastic terpolymeror an acrylnitrile-butadiene-styrene copolymer (ABS).

14. The grinding disc device according to claim 12, wherein the carrier disc is made from a polyamide PA6 or a glass fiber-reinforced polyamide PA6.

15. A method for producing a grinding disc device for a grinding apparatus by injection molding, comprising the steps of: introducing a grinding layer with a connection surface (F.sub.V) and an opposite abrasive grinding surface (F.sub.S) into a molding tool of an injection molding machine, in such a way that the connection surface (F.sub.V) of the grinding layer points in a direction of a predefined cavity of the molding tool, forming a carrier disc connection to the grinding layer by injecting a plastic material suitable for producing the carrier disc into a closed molding tool at a predefined temperature and under a predefined pressure, such that the plastic material of the carrier disc is sprayed immediately and directly onto the connection surface (F.sub.V) of the grinding layer thereby producing the grinding disc device.

16. The method according to claim 15, wherein the carrier disc is constituted in one piece with a hub part and/or that slots distributed over the periphery of the carrier disc are formed for a passage of cooling air.

17. The method according to claim 16, wherein an inner thread is formed in the hub part for the fastening of the grinding disc device on a drive shaft of the grinding apparatus and/or that the hub part is formed with corresponding cooling air passage slots.

18. The method according to any one of claim 15, wherein a flat, circular vulcanised fiber disc with a scattered ceramic grain abrasive medium is used as a grinding layer and that a glass fiber-reinforced polyamide PA6 is the plastic material for the carrier disc sprayed onto the grinding layer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The invention will be explained below in greater detail with the aid of examples of embodiment in connection with the drawings.

[0036] FIG. 1 shows a diagrammatic plan view of a first example of an embodiment of the grinding disc device according to the invention;

[0037] FIG. 2 shows a cross-section through the grinding disc device of FIG. 1;

[0038] FIG. 3 shows a perspective view of the grinding disc device of FIG. 1;

[0039] FIGS. 4-6 show an alternative embodiment of the grinding disc device according to the invention in plan view, in a cross-sectional representation, and in a perspective view;

[0040] FIGS. 7-9 show a further alternative embodiment of the grinding disc device according to the invention, wherein the grinding layer comprises grinding lamellas, in plan view, in a cross-sectional representation, and in a perspective view;

[0041] FIGS. 10-12 show a further alternative embodiment of the grinding disc device according to the invention, wherein the grinding layer comprises grinding lamellas, in a view from beneath, in a cross-sectional representation, and in a perspective view from beneath;

[0042] FIGS. 13-15 show a further alternative embodiment of the grinding disc device according to the invention, wherein the grinding layer comprises grinding lamellas, in a view from beneath, in a cross-sectional representation, and in a perspective view from beneath;

[0043] FIGS. 16-18 show yet another embodiment of the grinding disc device according to the invention, in plan view, in a cross-sectional representation, and in a perspective view and

[0044] FIGS. 19-21 show yet another embodiment of the grinding disc device according to the invention, in plan view, in a cross-sectional representation, and in a perspective view.

DETAILED DESCRIPTION OF THE INVENTION

[0045] All the examples of embodiment described below have in common that grinding disc device 10, according to the invention, comprises an essentially circular carrier disc 12 provided with an abrasive grinding layer 14, such that grinding layer 14 and carrier disc 12 are immediately and directly connected to one another without an intermediate layer. The side of grinding disc device 10 on which abrasive grinding layer 14 is arranged represents an underside U of grinding disc device 10. Opposite underside U of grinding disc device 10 lies an upper side O defined by carrier disc 12.

[0046] Carrier disc 12 is produced by means of injection molding and is directly sprayed onto grinding layer 14 thereby constituting grinding disc device 10 according to the invention. Carrier disc 12 is made of plastic, for example ABS, since the material is food-safe, has a sufficient elasticity, and has a long life. Other injectable plastics can also be used for carrier disc 12. More preferably, carrier disc 12 is made of a polyamide, in particular of polyamide PA6, and even more preferably of glass fiber-reinforced polyamide with for example a 30% glass fiber content, such as for example PA6-GF30.

[0047] In injection molding, which numbers among the primary shaping processes, the plastic for carrier disc 12, for example ABS or PA6, is plasticised and injected under pressure with an injection molding machine into a shaping hollow space, i.e. the cavity of the molding tool. The plastic material transforms back into the solid state by cooling. For the production of grinding disc device 10 according to the invention, grinding layer 14 is first placed into the cavity of the molding tool prior to the injection of the plastic material, in such a way that the side of grinding layer 14 forming a grinding surface F.sub.S lies against an inner wall of the cavity and a connection surface F.sub.V of grinding layer 14 is thus facing the hollow space. The subsequent injection of the plastic material into the shaping hollow space takes place under pressure in a range from 500 bar to 2000 bar and at a temperature in a range from 200 C. to 330 C. The plastic material is thus sprayed directly onto connection surface F.sub.V of grinding layer 14. As a result of the hardening in the injection molding machine, the plastic material of grinding disc 12 solidifies and is directly bonded to connection surface VF of grinding layer 14 or is connected in a material-locking manner to the latter.

[0048] In the example of the embodiment of FIGS. 1 to 3, grinding layer 14, comprising a connection surface F.sub.V and a grinding surface F.sub.S, consists of a flat, circular sanding disc 16, wherein carrier disc 12 is sprayed directly by injection molding onto connection surface F.sub.V of grinding layer 14 or sanding disc 16 without plastic being applied between the two latter. This takes place by means of injection molding in a suitable injection molding machine as described above.

[0049] Grinding layer 14 is first introduced or placed into the hollow space of the molding tool. More precisely, grinding layer 14 is placed into the hollow space of the molding tool such that connection surface F.sub.V of grinding layer 14 is facing the hollow space, i.e. grinding surface F.sub.S is facing an inner wall or hollow-space wall of the molding tool and in particular lies against the latter. The plasticised plastic material of carrier disc 12 is then injected into the cavity under pressure and at raised temperature. Following a short hardening time of less than one minute, the plastic of carrier disc 12 is hard and firmly connected in a durable manner to sanding disc 16 or grinding layer 14.

[0050] In the example of the embodiment of FIG. 1 to FIG. 3, a hub part 18 is formed in one piece with carrier disc 12 at upper side O of grinding disc device 10, from which hub part ventilation ribs 20 extend radially outwards. The ventilation ribs 20 provide for a sufficient cooling air flow over the surface of carrier plate 12 at the speeds generated during operation.

[0051] As FIGS. 2 and 3 show, hub part 18 comprises an inner thread 22, which is also formed in the injection molding, so that carrier disc 12 can be fastened on a drive shaft of a grinding apparatus, in particular a grinding machine, such as for example an angle grinder.

[0052] Essentially annular grinding layer 14, which comprises a central perforation in the region of hub part 18, comprises an annular, continuous connection surface F.sub.V and an annular, continuous grinding surface F.sub.S, wherein the circular surfaces extend over more than 90% of the total area of underside U of grinding disc device 10.

[0053] For further, improved cooling, slots 24 are designed or formed distributed over the outer periphery or over upper side O of carrier disc 12. The slots 24 provide for the passage of cooling air both against connection surface F.sub.V of grinding layer 14, which can also be seen as the inner surface, as well as against the machined workpiece. Cooling air slots 24 are fashioned according to the teaching known from German Patent No. DE 10 2016 102 037 B4, which is incorporated herein by reference.

[0054] FIGS. 4 to 6 show a variant of the embodiment of FIG. 1 to FIG. 3, wherein carrier disc 12 is also sprayed directly and without adhesive onto grinding layer 14. Diverging from the example of FIG. 1 to FIG. 3, central hub part 18 is constituted with a flat dish-shaped and has ventilation ribs. In this example of the embodiment of FIGS. 4 to 6, the central perforation of grinding layer 14 in the region of hub part 18 is larger than in the example of FIGS. 1 to 3, so that the surface segment area of annular, continuous connection surface F.sub.V and grinding surface F.sub.S in the total area of underside U of grinding disc device 10 is smaller than in the example of FIGS. 1 to 3.

[0055] In the alternative, also preferred variant of FIGS. 7 to 9, grinding layer 14 comprises grinding lamellas 26 arranged fan-shaped. The plastic of carrier disc 12 is also sprayed without an intermediate adhesive onto grinding lamellas 26 arranged fan-shaped. Grinding lamellas 26 arranged fan-shaped again form a flat grinding layer 14 with connection surface F.sub.V and grinding surface F.sub.S, which are also constituted in this embodiment as respective annular, continuous surfaces on account of the overlaps of grinding lamellas 26 arranged fan-shaped.

[0056] In the embodiment of FIGS. 10 to 12, hub part 18, in the same way as in the example of the embodiment of FIGS. 4 to 6, does not have any ventilation ribs. The air slots at the outer periphery of carrier disc 12 are also absent in this example of the embodiment.

[0057] FIGS. 13 to 15 show a modified embodiment with a carrier disc 12 constituted similar to the example of FIGS. 4 to 6, wherein here, as also in the example of FIGS. 10 to 12, grinding layer 14 comprises grinding lamellas 26 arranged fan-shaped, onto which carrier disc 12 is directly sprayed.

[0058] Finally, FIGS. 16 to 18 show an embodiment with a carrier disc 12, which has cooling air slots 24 at the outer periphery for the passage of cooling air. The flat, roughly dish-shaped hub 18 of carrier disc 12 also comprises, in addition to ventilation ribs 20, cooling air passage slots 28 for the passage of cooling air. Grinding layer 14 comprises grinding lamellas 26 arranged fan-shaped.

[0059] In FIGS. 19 to 21, an example of the embodiment of grinding disc device 10 is shown, wherein grinding layer 14 is formed by a grinding disc or a sanding disc 16. The grinding disc is a vulcanised fiber disc, wherein grinding surface F.sub.S is formed by a scattered ceramic grain abrasive medium.

[0060] In the case of grinding disc device 10 of the example of FIGS. 19 to 21, hub part 18 is constituted with ventilation ribs 20 and with an inner thread 22. No cooling air slots are provided, however, in carrier disc 12.

[0061] For the additional improvement of the stability, rigidity, and bending strength, reinforcing structures are constituted on carrier disc 12 at upper side O of grinding disc device 10, and more precisely in the represented example in the form of an annular rib 30. Furthermore, an annular groove 32 is provided, which serves to improve the elasticity during grinding.

LIST OF REFERENCE NUMBERS

[0062] 10 grinding disc device [0063] 12 carrier disc [0064] 14 grinding layer [0065] 16 grinding disc or sanding disc [0066] 18 hub part [0067] 20 ventilation rib [0068] 22 inner thread [0069] 24 cooling air slots [0070] 26 grinding lamellas [0071] 28 cooling air passage slots [0072] 30 annular rib [0073] 32 annular groove [0074] F.sub.S grinding surface [0075] F.sub.V connection surface [0076] O upper side [0077] U underside