ROLLER, IN PARTICULAR FOR A SLIDING DOOR

Abstract

A roller, in particular for a sliding door of a vehicle, includes a main part having a running surface pointing radially outward. The running surface can be coupled to a guide rail of a sliding door. The roller also includes a central bore, penetrating the main part at least in part, for receiving a bearing arrangement for rotatable mounting of the main part. A roller which is cost-effective to manufacture and is additionally durable is created in that at least the running surface consists of a radiation-crosslinked plastic having a gel value in formic acid between 20% and 60%.

Claims

1–16. (canceled)

17. A roller for a sliding door of a vehicle, comprising: a main body with a running surface pointing radially outward, wherein the running surface is coupleable to a guide rail of the sliding door; and a central bore, which extends at least partially through the main body, for receiving a bearing arrangement for rotatable mounting of the main body, at least the running surface consisting of a radiation-crosslinked plastic having a gel value in formic acid of between 20% and 60%.

18. The roller according to claim 17, wherein the main body consists of a radiation-crosslinkable plastic.

19. The roller according to claim 17, wherein the radiation-crosslinked plastic comprises a polyamide.

20. The roller according to claim 17, wherein the radiation-crosslinked plastic comprises a crosslinking additive.

21. The roller according to claim 20, wherein the crosslinking additive is a polyfunctional monomer.

22. The roller according to claim 20, wherein the crosslinking additive is one of triallyl isocyanurate and triallyl cyanurate.

23. The roller according to claim 20, characterized in that the crosslinking additive is contained in the radiation-crosslinked plastic in a concentration of between 0.01% and 20%.

24. The roller according to claim 20, wherein the crosslinking additive is contained in the radiation-crosslinked plastic in a concentration of between 12.5% and 17.5%.

25. The roller according to claim 24, wherein the concentration is approximately 15%.

26. The roller according to claim 17, wherein the gel value in formic acid is between 35% and 59%.

27. The roller according to claim 17, wherein the radiation-crosslinked plastic has a modulus of elasticity of between 3000 MPa and 4000 MPa.

28. The roller according to claim 27, wherein the modulus of elasticity is approximately 3500 MPa.

29. The roller according to claim 17, wherein the radiation-crosslinked plastic has a Charpy impact toughness of between 50 kJ/m.sup.2 and 55 kJ/m.sup.2 at 23° C.

30. The roller according to claim 30, wherein the Charpy impact toughness is approximately 52 kJ/m.sup.2 at 23° C.

31. The roller according to claim 17, wherein the radiation-crosslinked plastic has a Charpy notched impact toughness of between 3 kJ/m.sup.2 and 7 kJ/m.sup.2 at 23° C.

32. The roller according to claim 31, wherein the Charpy notched impact toughness is approximately 5 kJ/m.sup.2 at 23° C.

33. A method for producing the roller according to claim 17, wherein the method comprises the steps of: injection molding the main body of the roller in a molding tool, a radiation-crosslinkable plastic being used as a base material; demolding the injection-molded main body from the molding tool; and irradiating at least the running surface of the main body with beta radiation, a dose of the beta radiation being between 90 kGy and 110 kGy and the irradiation has a radiation energy of approximately 7 MeV to 13 MeV.

34. The method according to claim 33, wherein after the injection-molded main body has been demolded, the roller is arranged lying in an elastic covering during the irradiation.

35. The method according to claim 33, wherein the dose of the beta radiation is approximately 100 kGy and the irradiation has a radiation energy of approximately 10 MeV.

Description

BRIEF SUMMARY OF THE DRAWINGS

[0022] The present disclosure is explained in more detail in the following with reference to the accompanying drawing, using a preferred exemplary embodiment of the present disclosure.

[0023] FIG. 1 shows a preferred exemplary embodiment of a roller according to the present disclosure, in a side view sectioned longitudinally.

DETAILED DESCRIPTION

[0024] FIG. 1 shows a preferred exemplary embodiment of a roller according to the present disclosure, in a side view sectioned longitudinally. The roller 1 comprises a cylindrically symmetrical main body 2 made of a radiation-crosslinked plastic. In the

[0025] exemplary embodiment shown here, the base material of the main body 2 is polyamide 66 (PA 66), wherein a crosslinking additive having a proportion of approximately 15% was supplied to the polyamide. In the exemplary embodiment shown here, the crosslinking additive is triallyl cyanurate.

[0026] The main body 2 has been produced via an injection molding process, so that the production costs for the roller 1 are advantageously low. Subsequently, the main body 2 was subsequently radiation-crosslinked by means of beta radiation with an energy of 10 MeV and a radiation dose of 100 kGy.

[0027] The main body 2 has a running surface 3 on an upper portion, which running surface can be brought into engagement with a guide rail of a guide arrangement (not shown here). The running surface 3 has a slightly outwardly curved shape, so that the rolling resistance upon displacement of the sliding door is as small as possible and the displacement of the sliding door is accordingly easily possible.

[0028] The main body 2 further has a central bore 4, extending completely through the main body 2, which enables the receiving of a bearing arrangement for the rotatable mounting of the main body 2 about an axis of rotation L. In the exemplary embodiment shown here, the bore 4 is designed as a stepped bore so that the bore 4 has a first bore portion 4a and a second bore portion 4b, wherein the first bore portion 4a has a smaller inner diameter than the second bore portion 4b.

[0029] The first bore portion 4a extends in the axial direction along the axis of rotation L, from an underside 2a of the main body 2 to the second bore portion 4b. In the region of the underside 2a, the first bore portion 4a has a first bevel 5, which facilitates the passage of a bearing pin for the rotatable mounting of the main body 2. The second bore portion 4b extends in the axial direction along the axis of rotation L, from the first bore portion 4a to an upper side 2b of the main body 2. A radially circumferential groove 6 is provided in the second bore portion 4b, which groove can be used for the pressing-in or axial securing of a bearing element in the main body 2 via a tension ring.

[0030] Finally, the second bore portion 4b has, in a region of the upper side 2b of the main body, a second bevel 7 which facilitates the insertion of the bearing element into the open receptacle formed by the second hole portion 4b. The annular step 8, formed between the first bore portion 4a and the second portion 4b, forms a stop surface for the bearing element.

[0031] The present disclosure has been explained in the preceding using an exemplary embodiment in which triallyl cyanurate is used as a crosslinking additive. It is understood that the use of other crosslinking additives is also possible, insofar as a crosslinking activated via subsequent irradiation of the roller or main body that is preformed after the injection molding process is effectively possible.

[0032] The present disclosure has been explained in the preceding using an exemplary embodiment in which a radiation dose of 100 kGy at a beam energy of 10 MeV of a beta radiation was used for radiation-crosslinking. It is understood that these parameters are variable insofar as, in the roller according to the present disclosure which is present at the end of the manufacturing process, a certain degree of crosslinking, preferably a gel value in the range of from 35% to 59% in formic acid, is achieved.

[0033] The present disclosure has been explained in the preceding using an exemplary embodiment in which the central bore is designed as a stepped bore. It is understood that the central bore can also be designed as a simple bore, insofar as an axial securing of a bearing element for enabling a rotational movement of the main body of the roller about the axis of rotation L is possible in the central bore.