BEARING BUSH

Abstract

A bearing bush for supporting a motor vehicle part includes an inner tube made of a metal, a sliding sleeve made of a first plastic material and mounted rotatably on the inner tube, and an elastomer bearing which surrounds the sliding sleeve and has at least a first elastomer body and an outer sleeve. A sliding layer made of a second plastic material is applied to an outer circumferential surface of the inner tube, the first plastic material and the second plastic material forming a tribological pairing either of two different polymers from the groups of polyamides, polyoxymethylenes, polyketones, fluoropolymers, polyethylene terephthalates or polybutylene terephthalates, or the tribological pairing being formed from polyketone against polyketone, wherein the polymers of the tribological pairings each are present in a continuous thermoplastic polymer phase.

Claims

1.-16. (canceled)

17. A bearing bush for supporting a motor vehicle part, the bearing bush comprising: an inner tube comprised of a metal, a sliding sleeve comprised of a first plastic material and mounted rotatably on the inner tube, and an elastomer bearing that surrounds the sliding sleeve and has at least a first elastomer body and an outer sleeve, wherein a sliding layer comprised of a second plastic material is disposed on an outer circumferential surface of the inner tube, the first plastic material and the second plastic material forming a tribological pairing either of two different polymers from the groups of polyamides, polyoxymethylenes, polyketones, fluoropolymers, polyethylene terephthalates or polybutylene terephthalates, or the tribological pairing being formed from polyketone against polyketone, and wherein the polymers of the tribological pairings each are present in a continuous thermoplastic polymer phase.

18. The bearing bush according to claim 17, wherein the polyoxymethylene is a polyoxymethylene copolymer or a polyoxymethylene homopolymer.

19. The bearing bush according to claim 17, wherein the polyamide is an aliphatic polyamide or a partially aromatic polyamide.

20. The bearing bush according to claim 17, wherein the sliding sleeve and/or the sliding layer includes at least one additive.

21. The bearing bush according to claim 20, wherein the at least one additive comprises polytetrafluoroethylene, graphite, carbon nanofibres, carbon fibres, aramid fibres, minerals, molybdenum disulphide, talcum, oils, waxes, glass beads and/or glass fibres.

22. The bearing bush according to claim 17, wherein the sliding layer is applied by a powder coating process.

23. The bearing bush according to claim 17, wherein the sliding layer has a thickness between approx. 50 μm and approx. 300 μm.

24. The bearing bush according to claim 17, wherein the sliding layer has a thickness between approx. 70 μm and approx. 150 μm.

25. The bearing bush according to claim 17, wherein an adhesive layer is applied to the outer circumferential surface of the inner tube.

26. The bearing bush according to claim 17, wherein on a surface facing the sliding layer, the sliding sleeve has at least one recess for receiving a lubricant.

27. The bearing bush according to claim 17, wherein the sliding sleeve is slotted or formed in several parts.

28. The bearing bush according to claim 17, wherein the elastomer bearing is slotted or formed in several parts.

29. The bearing bush according to claim 17, wherein the elastomer bearing is connected to the sliding sleeve in a form-locking, force-locking and/or material-locking manner.

30. The bearing bush according to claim 17, wherein the elastomer bearing includes an inner sleeve enclosing the sliding sleeve.

31. The bearing bush according to claim 30, wherein the elastomer bearing has a second elastomer body that is connected to an inner circumferential surface of the inner sleeve.

32. The bearing bush according to claim 17, wherein a sealing system is provided that seals a sliding gap.

33. The bearing bush according to claim 17, wherein a path limiting device is provided that limits movement of the sliding sleeve in a longitudinal direction of the bearing bush.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In the following, the bearing bush as well as other features and advantages are explained in more detail on the exemplary embodiments schematically shown in the figures. Shown here:

[0034] FIG. 1 a longitudinal section through a bearing bush according to a first embodiment;

[0035] FIG. 2 a cross-section through the bearing bush shown in FIG. 1 along line II-II;

[0036] FIG. 3 an enlarged cross-section through an inner tube with a sliding layer applied to it;

[0037] FIG. 4 an enlarged section of detail IV from FIG. 3;

[0038] FIG. 5 an enlarged cross-section through a sliding sleeve;

[0039] FIG. 6 a longitudinal section through a bearing bush according to a second embodiment;

[0040] FIG. 7 a cross-section through the bearing bush shown in FIG. 6 along the line VI-VI;

[0041] FIG. 8 a cross-section through a bearing bush according to a third embodiment; and

[0042] FIG. 9 a cross-section through the elastomer bearing shown in FIG. 8.

DETAILED DESCRIPTION

[0043] FIGS. 1 and 2 show a bearing bush 10 which is used to support a motor vehicle part (not shown), in particular a chassis component such as a leaf spring. For this purpose, the bearing bush 10 is inserted, in particular pressed, into an unrepresented bearing receiving eye.

[0044] The bearing bush 10 has an inner tube 12 made of a metal, a sliding sleeve 14 made of a first plastic, which is rotatably mounted on the inner tube 12, and an elastomer bearing 16.

[0045] Preferably, the inner tube 12 is made of steel or aluminium and has a receiving opening 13 for connecting a motor vehicle part (not shown) to the bearing bush 10.

[0046] As can be seen especially in FIGS. 3 and 4, an adhesive layer 21 is applied to an outer circumferential surface 18 of the inner tube 12. The adhesive layer 21 is an adhesion promoter made of an epoxy resin and is preferably applied by means of electrostatic powder coating. Advantageously, the adhesive layer 21 has a layer thickness of 10 to 100 μm, preferably between 20 and 40 μm. A sliding layer 20 made of a second plastic is applied to the adhesive layer 21, the sliding sleeve 14 and the sliding layer 20 forming a tribological pairing 22. The sliding layer 20 is preferably applied to the adhesive layer 21 by electrostatic powder coating and has a thickness between approx. 50 μm and approx. 300 μm, in particular between approx. 80 μm and approx. 200 μm. In addition, the sliding layer 20 can also be applied directly to the outer circumferential surface 18 of the inner tube 12.

[0047] The sliding layer 20 forms a continuous polymer layer on the inner tube 12, wherein the sliding layer 20 may be from the groups of polyamides (PA), polyoxymethylenes (POM), polyketones (PK), fluoropolymers, polyethylene terephthalates (PET) or polybutylene terephthalates (PBT).

[0048] As shown in FIG. 5, the sliding sleeve 14 is slotted. This allows a preload to be applied to the tribological pairing 22 when mounting the bearing bush 10 on a bearing receiving eye in order to achieve a clearance-free contact between the sliding sleeve 14 and the sliding layer 20. The sliding sleeve 14 can be from the groups of polyamides (PA), polyoxymethylenes (POM), polyketones (PK), fluoropolymers, polyethylene terephthalates (PET) or polybutylene terephthalates (PBT).

[0049] If the sliding layer 20 is made of polyamide, then the sliding sleeve 14 is made of polylyoxymethylene, polyethylene terephthalate, polybutylene terephthalate or polyketone. If the sliding layer 20 is made of polyoxymethylene, then the sliding sleeve 14 is made of polyamide, polyethylene terephthalate, polybutylene terephthalate or polyketone. If the sliding layer 20 is made of polybutylene terephthalate, then the sliding sleeve 14 is made of polyoxymethylene, polyamide, or polyketone. If the sliding layer 20 is made of polyketone, then the sliding sleeve 14 is made of polyamide, polyethylene terephthalate, polybutylene terephthalate or polyoxymethylene, but may also be made of polyketone.

[0050] Polyoxymethylene may be a polyoxymethylene copolymer (POM-C) or a polyoxymethylene homopolymer (POM-H). The polyamide may be an aliphatic polyamide or a partially aromatic polyamide. Aliphatic polyamides may be polyamide 6 (PA6), polyamide 12 (PA12), polyamide 46 (PA46), polyamide 66 (PA66) or polyamide 666 (PA666).

[0051] To improve the tribological, mechanical and/or thermal properties of the sliding layer 20, at least one additive 52 may be embedded in the sliding layer 20, as shown in FIG. 4. Additive 52 may be polytetrafluoroethylene (PTFE), graphite, carbon nanofibres, carbon fibres, aramid fibres, minerals, molybdenum disulphide, talcum, oils, waxes, glass beads and/or glass fibres. As can also be seen in FIG. 4, the additive 52 is statistically embedded in the sliding layer 20 in such a way that the additive 52 is also arranged directly at the surface of the sliding layer 20 and can therefore be tribologically effective immediately.

[0052] The elastomer bearing 16 has a first elastomer body 24 and an outer sleeve 26 and is connected to the sliding sleeve 14 in a form-fit, force-fit and/or material-fit manner. In the embodiment shown in FIGS. 1 and 2, the elastomer bearing 16 is bonded to the sliding sleeve 14 by the first elastomer body 24 being vulcanised to the sliding sleeve 14. The first elastomer body 24 is also slotted in order to apply a preload to the tribological pairing 22 when mounting the bearing bush 10 on a bearing receiving eye and to thus achieve a clearance-free contact between the sliding sleeve 14 and the sliding layer 20.

[0053] As can also be seen in FIG. 2, the outer sleeve 26 is made of two parts, wherein the outer sleeve 26 has a projection 28 which protrudes radially inwards into a corresponding recess 30 of the sliding sleeve 14. The outer sleeve 26 may be made of metal or plastic.

[0054] The bearing bush 10 also has a stop device 32 which limits movement of the sliding sleeve 14 relative to the inner tube 12 in the longitudinal direction L of the bearing bush 10. The stop device 32 has a first annular disc 34a and a second annular disc 34b, the first annular disc 34a being connected to a first end face 36a of the inner tube 12 and the second annular disc 34b being connected to a second end face 36b of the inner tube 12. For this purpose the first end face 36a has a first shoulder 38a and the second end face 36b has a second shoulder 38b, wherein the first annular disc 34a is pushed, in particular pressed, onto the first shoulder 38a, and the second annular disc 34b is pushed, in particular pressed, onto the second shoulder 38b.

[0055] A sealing system 42 is provided for sealing a sliding gap 40. The sealing system 42 consists of a first projecting axial end area 44a of the first elastomer body 24 and a second axially projecting end area 44b of the first elastomer body 24. Two radially inwardly projecting sealing lips 46 are arranged at each end area 44a, 44b. The sealing lips 46 are in contact with the annular discs 34a, 34b in order to reliably seal the sliding gap 40 against the penetration of environmental influences.

[0056] In order to reduce friction within the tribological pairing 22, the sliding sleeve 14 has on an inner surface 48 several recesses 50 extending in axial direction A, which serve as lubricant depots, as shown in FIG. 2.

[0057] In the following, further embodiments for the bearing bush 10 and the elastomer bearing 16 are described, wherein the same reference signs are used for identical and functionally identical parts.

[0058] The FIGS. 6 and 7 show a second embodiment of the bearing bush 10, which differs from the first embodiment in that the elastomer bearing 16 has an inner sleeve 54, which is connected to the first elastomer body 24 in a material-locking manner, in particular it is vulcanised onto the first elastomer body 24. The inner sleeve 54 made of metal or plastic is pushed, in particular pressed, onto the sliding sleeve 14. In the second embodiment, the outer sleeve 26 is made in one piece and has no projection 28 which lies in a corresponding recess 30 of the sliding sleeve 14.

[0059] According to FIG. 7 the sliding sleeve 14, the inner sleeve 54, the first elastomer body 24 and the outer sleeve 26 are slotted. In particular, the elastomer bearing 16 has a slot 55 extending through the outer sleeve 26, the first elastomer body 24 and the inner sleeve 54. Furthermore, the sliding sleeve 14 in the second embodiment has no recesses 50 serving as lubricant depots.

[0060] FIG. 8 shows a third embodiment of the bearing bush 10 which differs in particular from the second embodiment in that the elastomer bearing 16 has a second elastomer body 56 which is connected to an internal side 57 of the intermediate bush 54.

[0061] As can be seen in FIG. 9 in particular, the second elastomer body 56 is formed from radially inwardly projecting thickenings 58. The second elastomer body 56, together with the slotted sliding sleeve 14, is used to apply a preload to the tribological pairing 22 during the assembly of the bearing bush 10, thus ensuring clearance-free contact between the sliding sleeve 14 and the sliding layer 20.