METHOD FOR PRODUCING A BEARING ASSEMBLY

Abstract

A method for producing a bearing assembly for mounting a control shaft, for example a camshaft, may include: providing a bearing; arranging at least two rings on respective axial front sides of the bearing; pushing the bearing together with the at least two rings onto an assembly mandrel; pre-tensioning the at least two rings against the respective axial front sides of the bearing; at least one of (i) pushing a shrink hose over the bearing and the at least two rings and heating the shrink hose, and (ii) winding a film strip over the bearing and the at least two rings; and withdrawing the assembly mandrel.

Claims

1. A method for producing a bearing assembly for mounting a control shaft, comprising: providing a bearing, arranging at least two rings on respective axial front sides of the bearing; pushing the bearing together with the at least two rings onto an assembly mandrel, pre-tensioning the at least two rings against the respective axial front sides of the bearing; at least one of (i) pushing a shrink hose over the bearing and the at least two rings and heating the shrink hose, and (ii) winding a film strip over the bearing and the at least two rings; and withdrawing the assembly mandrel.

2. The method according to claim 1, wherein the film strip is wound over the bearing and the at least two rings, and wherein winding the film strip includes winding the film strip under tension and partially overlapping over the bearing and the at least two rings.

3. A bearing assembly comprising, a bearing; at least two rings arranged on a respective axial front side of the bearing; and at least one of: a shrink hose shrunk over the bearing and the at least two rings; and a film strip wound over the bearing and the at least two rings.

4. The bearing assembly according to claim 3, wherein the shrink hose is arranged over the bearing and the at least two rings and includes at least one tear tab.

5. The bearing assembly according to claim 3, wherein the shrink hose further includes a material weakening to facilitate removal.

6. The bearing assembly according to claim 5, wherein the material weakening is configured as a perforation.

7. The bearing assembly produced according to claim 1, wherein the film strip is wound over the bearing and the at least two rings under tension and partially overlapping.

8. The bearing assembly according to claim 3, wherein at least one of the at least two rings includes at least one of a plastic material and a metal material.

9. The bearing assembly according to claim 3, wherein the at least two rings include at least one axial front-side oil conveying structures.

10. The bearing assembly according to claim 3, wherein the at least two rings have an outside diameter that is smaller than an outside diameter of the bearing.

11. The bearing assembly according to claim 3, wherein at least one of: the at least two rings include at least one radially extending structure disposed on an outer radial side at least in an overlap region of the at least one of the shrink hose and the film strip; and the at least one of the shrink hose and the film strip include a radially interior layer to facilitate a sealing effect.

12. The bearing assembly according to claim 3, wherein the bearing is one of a plain bearing and a roller bearing.

13. A method for producing a control shaft, comprising: providing at least one pre-fabricated bearing assembly, wherein providing the at least one pre-fabricated bearing assembly includes: providing a bearing; arranging at least two rings on a respective axial front side of the bearing; pushing the bearing together with the at least two rings onto an assembly mandrel; pre-tensioning the at least two rings against the respective axial front side of the bearing; covering the bearing and the at least two rings with a protective material, wherein covering the bearing and the at least two rings with the protective material includes at least one of: pushing a shrink hose over the bearing and the at least two rings and heating the shrink hose; and winding a film strip over the bearing and the at least two rings; and withdrawing the at least one pre-fabricated bearing assembly from the assembly mandrel; arranging the at least one pre-fabricated bearing assembly and at least one control element on a control-shaft shaft; and removing the protective material from the at least one bearing assembly.

14. The method according to claim 13, further comprising grinding the at least one control element and cleaning the control shaft after arranging the at least one pre-fabricated bearing assembly and the at least one control element on the control-shaft shaft.

15. The method according to claim 13, wherein removing the protective material includes removing at least one of the shrink hose and the film strip by at least one of scoring, cutting, and lasering.

16. The method according to claim 13, further comprising fixing the bearing axially and displacing the control shaft in an axial direction after removing the protective material from the at least one bearing assembly.

17. The method according to claim 13, wherein removing the bearing material from the at least one bearing assembly includes separating the shrink hose along a material weakening perforation.

18. The method according to claim 13, wherein the protective material is the film strip, and wherein winding the film strip includes winding the film strip under tension and partially overlapping over the bearing and the at least two rings.

19. The method according to claim 1, wherein the shrink hose is pushed over the bearing and the at least two rings, and wherein heating the shrink hose includes shrinking the shrink hose onto the bearing and the at least two rings.

20. The bearing assembly according to claim 9, wherein the at least one front-side oil conveying structure includes at least one of a recessed groove, an elevated groove, a recessed slot, an elevated slot, a recessed web, an elevated web, a recessed hemispherical elevation, and an elevated hemispherical elevation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In the figures, schematically in each case

[0015] FIG. 1 shows a sectional view through a bearing assembly according to the invention during assembly on an assembly mandrel,

[0016] FIG. 2 shows a sectional view through a camshaft produced according to the invention before grinding the cams with shrink hose still applied to the bearing assemblies,

[0017] FIG. 3 shows a detailed view from FIG. 2,

[0018] FIG. 4 shows a sectional view through a cylinder head or a cylinder head over with installed camshaft with shrink hoses removed from the bearing assemblies at the same time,

[0019] FIG. 5 shows a sectional view through the control shaft during axial displacement of the control-shaft shaft to create a clearance.

DETAILED DESCRIPTION

[0020] According to FIG. 1, in a method according to the invention for producing a bearing assembly 1 by means of which subsequently, for example a control shaft/camshaft 2 is mounted in a cylinder head 3 or a cylinder head cover 4 (cf. FIG. 4), a bearing 5 is firstly prepared or produced by mounting or arranging roller bodies 6 in a bearing ring 7. The term “control shaft” can hereinafter frequently be equated to the term “camshaft”. The roller bodies 6 can in this case, for example, be configured as rolls or as needles but also as spheres. This bearing 5 together with two rings 8 arranged on the front side thereto, in particular with plastic or metal rings, is then pushed onto an assembly mandrel 9 (cf. FIG. 1), where the two rings 9 are pre-tensioned towards the front sides of the bearing 5 by means of a corresponding sleeve 10. This is brought about by the sleeve 10 pressing onto the upper ring 8 and the lower ring 8 resting on a bracket or a stop 11 of the assembly mandrel 9. A shrink hose 12 is then pushed over the bearing 5 and the two rings 8 and shrunk onto these by heating. Alternatively to this, a film strip 12′ can also be wound over the bearing 5 and the two rings 8. The film strip 12 is thereby wound under tension and partially overlapping over the bearing 5 and the two rings 8 in order to ensure tightness.

[0021] FIG. 1 shows the state of the shrink hose 12 before heating, whereas FIGS. 2 and 3 show the state after shrinking the shrink hose 12 onto the rings 8 and the bearing 5 or the film strip 12′ wound under tension over the bearing 5 and the two rings 8. This is wound in a partially overlapping manner so that gaps can be avoided and a tight packing for the bearing 5 and the ring 8 can be ensured. The bearing assembly 1 now thus pre-fabricated can now be removed from the assembly mandrel 9. As can be deduced from FIG. 1, the bracket 11 or the stop 11 has the effect that the shrink hose 12 can be pushed further downwards on the front side so that for example, it is also possible for the rings 8 to be embraced by the shrink hose 12 on the front side. The rings 8 can in this case have a structuring radially on the outer side at least in the overlap region of the shrink hose 12. According to FIGS. 2 and 3, the shrink hose 12 thereby however does not embrace the front sides of the two rings but merely holds these firmly on its outer lateral surface.

[0022] The bearing assembly 1 according to the invention thus consists of the actual bearing 5, the bearing ring 7 and the roller bodies 6 mounted therein, the two rings 8 arranged on the front side thereto and the shrink hose 12 shrunk thereon, which fixes the two rings 8 on the bearing 5.

[0023] The shrunk-on shrink hose 12 or the wound-on film strip 12′ protects the bearing 5 during grinding of cams 13 from penetrating grinding particles and therefore from any accompanying damage. A tear tab 14, for example, can be provided on the shrink hose 12, which makes it easier to tear off and therefore remove the shrink hose 12 from the bearing assembly 1 after grinding. A film strip 12′ can be simply unwound. The shrink hose 12 can furthermore have a material weakening, for example, in the manner of a perforation which additionally simplifies the removal of the shrink hose 12 after grinding of the cams 13. The shrink hose 12 or the film strip 12′ can also have a layer which increases the sealing effect at least partially from inside, in particular an adhesive layer.

[0024] The bearing assembly 1 generally fabricated separately according to the invention is now slid onto a control-shaft shaft 15 during assembly of the control shaft/camshaft 2 with at least one control element, in particular a cam 13, where it is naturally clear that not only one bearing assembly 1 and one control element/cam 13 are slid onto the control-shaft shaft 15 but in each case a plurality thereof. When the bearing assemblies 1 are pushed onto the control-shaft shaft 15 and the control elements, in particular the cams 13 are joined to the control-shaft shaft 15, for example, by a thermal shrink fit, an after-treatment or finishing of the control element/cams 13 can be accomplished, in particular by grinding. The bearing assemblies 8 are held on the control-shaft shaft 15. When the finishing, for example, by grinding the cams 13 is completed, the camshaft 2 can be cleaned and the shrink hose 12 or the film strip 12′ can be opened and removed from the individual bearing assemblies 1, for example, by tearing on the tear tab 14 and the pre-fabricated camshaft 2 can be inserted into the cylinder head 3 or the cylinder head cover 4.

[0025] Before reaching the end position of the camshaft 2 in the cylinder head 3 or in the cylinder head cover 4, the control-shaft shaft 15 is moved to and fro slightly in the axial direction relative to the bearing 5 and a minimal distance 17 in the axial direction 16 between the two rings 8 and the bearing 5 is thereby created, enabling a clearance of the bearing 5.

[0026] Usually after removal of the shrink hose 12 or the film strip 12′, the bearings 5 of the control shaft 2 can be fixed axially to create the clearance before insertion in the cylinder head 3 and the control shaft 2 is displaced in the axial direction preferably by at least 1/10 mm as shown in FIG. 5. For this purpose an axial force is exerted on the control shaft 2 and at the same time the bearings 5 are held by means of retaining contours 23.

[0027] In order to be able to reliably ensure sufficient lubrication of the bearing 5 during operation of the control shaft 2 installed in an internal combustion engine 8, oil-conveying structures or oil conveying structures 20 (see detailed view from FIG. 3), in particular grooves, slots, webs or hemispherical elevations 22 can be provided on one of the front sides 19 of the two rings 8 facing the bearing ring 7, which enable a reliable transport of oil into the area between the roller bodies 6 and the control-shaft shaft 15 and thereby on the one hand enable reliable lubrication of the bearing 5 and on the other hand a smooth-running mounting of the control shaft 2.

[0028] If FIGS. 1 to 4 are viewed again, it can be see that the rings 8 have a smaller outside diameter than the bearing ring 7 with the result that a simplified insertion of the control shaft 2 into the relevant bearing opening 21 of the cylinder head 3 or cylinder head cover 4 is made possible.

[0029] Using the method according to the invention for producing the bearing assembly 1 according to the invention and the resulting method according to the invention for producing the control shaft 2, the latter can be produced significantly more simply and cost-effectively since in particular a laborious covering of the bearings 5 during grinding of the control elements, in particular the cams 13 is omitted. On the contrary the bearings 5 are protected from any unwanted ingress of grinding dust by means of the two rings 8 arranged on the front side thereto and the shrink hose 12 shrunk thereover or the film strip 12′ wound thereover. This can be removed significantly more simply compared to the protective cages known hitherto from the prior art, for example by simply tearing off or away or unwinding.