Bushing arrangement for centering two shaft sections to be joined

Abstract

Bushing arrangement (10) for centering two shaft sections to be joined with: - at least one external socket (12), and - at least one inner bushing (14) arranged radially inwards of the at least one outer bushing (12), wherein the at least one outer bushing (12) and the at least one inner bushing (14) are connected via at least one elastomer body (16) on which at least one sealing lip (18) is formed, wherein at least one circumferential recess (20) is formed in the elastomer body (16) which extends from an axial end of the bushing arrangement (10) into the elastomer body (16) such that the at least one recess (20) extends radially around the at least one sealing lip (18) and around at least one section (32) of the axial extension of the inner bushing (12), characterized in that the sealing lip (18) and the inner bushing (14) are arranged at an axial end region of the outer bushing (12).

Description

[0001] The present invention relates to a bushing arrangement for centering two shaft sections to be joined, comprising at least one outer bushing and at least one inner bushing arranged radially inward of the at least one outer bushing. The at least one outer bushing and the at least one inner bushing are connected via at least one elastomer body, on which at least one sealing lip is formed.

[0002] Such bushing arrangements are known from the prior art and are disclosed, for example, in documents DE 195 31 201 A1 and WO 2004 / 097239 A1.

[0003] Document DE 195 31 201 A1 discloses a centering device with a sleeve-shaped centering collar to which a rubber spring assembly is attached. The rubber spring assembly extends between the centering collar and an inner bushing that can guide a centering pin. The rubber spring assembly surrounds the inner bushing and includes a sealing lip. Following the sealing lip, the rubber spring assembly completely fills the radial area between the centering collar and the inner bushing.

[0004] WO 2004 / 097239 A1 discloses a bearing comprising a tube section and an insert embedded in the tube section. The central insert is embedded in and vulcanized to an elastic rubber centering sleeve. The centering sleeve has a first annular sealing lip and a second annular sealing lip. The elastic centering sleeve completely fills the radial area between the tube section and the central insert between the two sealing lips.

[0005] For further information on the state of the art, please refer to document WO 2004 / 097239 A1.

[0006] Devices known from the prior art for centering two shaft sections to be joined are frequently used and have proven their worth in practice.

[0007] However, it has been shown that further developments, for example in steering shafts and drive trains in the automotive sector, more frequently result in relatively large deflection angles, i.e. greater than 3°, between the shaft sections to be connected.

[0008] The applicant has recognized that at larger bending angles, the sealing lip may lift off, for example, a centering pin, which may impair the sealing function of the centering device or bushing arrangement.

[0009] Accordingly, it is an object of the present invention to further develop a bushing arrangement of the type described above in such a way that it fulfills its function safely and reliably even at relatively large bending angles.

[0010] This problem is solved by a device for centering two shaft sections to be joined, having the features of claim 1.

[0011] Further embodiments of the invention will be evident from the attached dependent claims.

[0012] In the bushing arrangement for centering two shaft sections to be joined according to the invention, at least one circumferential recess is formed in the elastomer body. The circumferential recess extends from an axial end of the bushing arrangement into the elastomer body such that the at least one recess extends radially around the at least one sealing lip and around at least one section of the axial extent of the inner bushing.

[0013] In this context, the axial extent of the inner bushing refers to its length in the direction of the central axis of the bushing assembly. Accordingly, the circumferential recess in the elastomer body overlaps at least an axial section of the inner bushing.

[0014] The recess in the elastomer body, which radially surrounds at least one sealing lip and at least one axial section of the inner bushing, allows the sealing lip and the inner bushing to be largely decoupled from the outer bushing. The sealing lip is coupled to the inner bushing and can follow its movement. This has the advantage that, at relatively large articulation angles typical for applications in steering shafts or drive trains (i.e., articulation angles in the range of 4–5°), the sealing lip follows the movement of the inner bushing and is not lifted from it by its connection to the outer bushing, thus losing its sealing effect. The sealing lip and the inner bushing are therefore largely independent of the outer bushing in their movement. Consequently, the sealing lip can reliably fulfill its sealing function even at relatively large articulation angles.

[0015] According to one embodiment of the invention, the at least one recess in the elastomer body can extend, at least partially, between the outer surface of the inner bushing and the inner circumferential surface of the outer bushing. Such a recess configuration can support the decoupling of the sealing lip and also the inner bushing from the outer bushing and prevent the sealing lip from lifting off at larger bending angles.

[0016] According to a further embodiment of the invention, an axial end region of the at least one recess can be radially enclosed between the inner bushing and the outer bushing. The recess terminates in a region of the elastomer body that is located radially between the inner bushing and the outer bushing.

[0017] To achieve guided movement between the outer and inner bushings under bending stresses of the bushing arrangement caused by the shaft sections to be connected, and to prevent excessive radial deflections between the inner and outer bushings, a further development of the invention provides that the at least one inner bushing has a circumferential section projecting towards the outer bushing. The inner bushing can bear against the outer bushing via this projecting section and the elastomeric body provided between the inner and outer bushings.

[0018] According to one embodiment of the invention, the at least one recess in the elastomer body can extend to the section of the at least one inner bushing projecting towards the outer bushing, i.e., the section of the inner bushing projecting towards the outer bushing limits the recess in the elastomer body in the axial direction.

[0019] At least one recess can extend into the elastomer body essentially parallel to the inner circumferential surface of the outer bushing. In other words, the recess extends in a direction parallel to the central axis of the bushing assembly.

[0020] To facilitate the decoupling of the sealing lip from the outer bushing and to better connect the sealing lip to the inner bushing, the cylindrical surface of the inner bushing can have a predetermined contour. According to one embodiment of the invention, the cylindrical surface of the inner bushing, viewed axially, can comprise a section extending parallel to the central axis, which is connected via a curved section to the section projecting towards the outer bushing. A further curved section can adjoin the projecting section, transitioning into a section extending parallel to the central axis of the bushing assembly. A chamfer can be provided at each of the axial ends of the inner bushing. In other words, a chamfer can be formed between the sections extending parallel to the central axis of the bushing assembly and the end faces of the inner bushing.

[0021] As an alternative to the embodiment described above, the outer surface of the inner bushing can also have a different contour. According to a further embodiment of the invention, the outer surface of the inner bushing, viewed in the axial direction, can comprise a linear section extending at an angle to the central axis, to which a curved section adjoins. The curved section can transition into the section projecting towards the outer bushing. The projecting section is connected via a curved section to a linear section extending at an angle to the central axis of the bushing arrangement.

[0022] With such a design of the inner bushing, it is conceivable that the inner bushing has no end faces or only very small end faces.

[0023] According to a further development of the invention, the outer surface of the inner bushing can be completely surrounded by the elastomer body.

[0024] It may also be provided that the elastomer body covers at least part of the end faces of the inner bushing. A bond between the bushings and the elastomer body is usually established via an adhesion promoter. In this case, it is also conceivable that the end faces of the inner bushing are coated with an adhesion promoter to bond the elastomer body.

[0025] Preferably, the inner circumferential surface of the outer bushing can be completely covered with the elastomer body.

[0026] According to the invention, the sealing lip and the inner bushing are arranged in an axial end region of the outer bushing. Thus, the sealing lip and the inner bushing are not arranged centrally in the outer bushing, but offset at an axial end region of the outer bushing.

[0027] According to a further development of the invention, the at least one recess in the at least one elastomer body can be radially surrounded by approximately 10 to 40% of the axial extent of the inner bushing.

[0028] The present invention further relates to a centering device with a bushing arrangement of the type described above.

[0029] Furthermore, the present invention relates to a torque transmission device with a bushing arrangement described above.

[0030] Exemplary embodiments of the present invention are described below with reference to the accompanying figures. These figures represent: Fig. 1 a perspective view of a bushing arrangement according to a first embodiment of the present invention; Fig. 2 a perspective, axis-containing sectional view of the bushing arrangement according to the first embodiment of the invention; Fig. 3 a section view containing the axle of the bushing arrangement according to the first embodiment of the invention; Fig. 4 an enlarged detail view of detail Z in Fig. 3; Fig. 5 a perspective view of a bushing arrangement according to a second embodiment of the invention; Fig. 6 a perspective, axis-containing sectional view of the bushing arrangement according to a second embodiment of the invention; Fig. 7 an axle-containing sectional view of the bushing arrangement according to the second embodiment; and Fig. 8 a detailed view of detail Z in Fig. 7.

[0031] Fig. Figure 1 shows a perspective view of a bushing arrangement according to a first embodiment of the invention, which is generally designated by 10.

[0032] The socket arrangement 10 comprises an outer socket 12 and an inner socket 12. Fig. 1. The inner bushing 14 is only partially visible. The outer bushing 12 and the inner bushing 14 are connected to each other via an elastomer body 16. A sealing lip 18 is formed on the elastomer body 16, which abuts the inner bushing 14 in the direction of the central axis M of the bushing arrangement 10. The sealing lip 18 is intended for sealing contact with, for example, a centering pin (not shown) of a centering device.

[0033] In Fig. 1 The recess 20 can be seen in a preliminary way, which extends in the axial direction of the central axis M into the elastomer body 16 in order to decouple the sealing lip 18 from the outer bushing 12.

[0034] The outer bushing 12 is tubular in shape and radially surrounds the inner bushing 14 and the elastomer body 16.

[0035] Fig. Figure 2 shows an axis-containing, perspective view of the bushing arrangement 10.

[0036] The outer bushing 12 is connected to the inner bushing 14 via the elastomer body 16. The inner bushing 14 has two axial end faces 22 and 24. The sealing lip 18 adjoins the end face 22 in the axial direction. The sealing lip 18 and the inner bushing 14 are arranged in an axial end region of the outer bushing 12, i.e., not centrally located within the outer bushing 12.

[0037] The recess 20 extends axially from an axial end of the outer bushing 12 into the elastomer body 16. The recess 20 runs parallel to an inner circumferential surface 26 of the outer bushing 12. The recess 20 radially surrounds the sealing lip 18 and a section of the extension of the inner bushing 14 in the direction of the central axis M of the bushing assembly 10. In other words, the recess 20 extends section by section between the inner circumferential surface 26 of the outer bushing 12 and the outer surface 28 of the inner bushing 14; that is, the axial end 30 of the recess 20 in the elastomer body 16 is radially enclosed between the inner circumferential surface 26 of the outer bushing 12 and the outer surface 28 of the inner bushing 14.

[0038] The elastomer body 16 is connected to the outer surface 28 of the inner bushing 12 and also partially spans the end faces 22 and 24 of the inner bushing 14. Optionally, the elastomer body 16 can also be connected to or bonded to the end faces 22 and 24 of the inner bushing 14. To bond the elastomer body 16 to the outer bushing 12 and the inner bushing 14, an adhesion promoter is first applied, and then the elastomer body 16 is vulcanized to the inner circumferential surface 26 of the outer bushing 12 and to the outer surface 28 of the inner bushing 14.

[0039] The elastomer body 12 is completely provided on the inner circumferential surface 26 of the outer bushing 12, i.e. a thin elastomer layer also spans the inner circumferential surface 26 of the outer bushing 12 in the area of ​​the recess 20.

[0040] Fig. Figure 3 shows a sectional view of the bushing arrangement 10, including the axis.

[0041] The inner bushing 14, or rather its outer surface 28, has a predetermined contour. A section 32 extending parallel to the central axis M is provided, starting from the end face 22. This section is connected via a curved section 34 to a section 36 projecting towards the outer bushing 12. The projecting section 36, in turn, is connected to a curved section 38, which transitions into a section 40 extending linearly to the central axis M. A circumferential chamfer 42 is provided on each of the end faces 22 and 24, and at the transitions between the end faces 22 and 24 and the sections 34 and 40 extending parallel to the central axis M.

[0042] In Fig. Figure 3 shows that the sealing lip 18 projects radially further towards the central axis M than the inner circumferential surface 44 of the inner bushing 14. This is because the sealing lip 18 is intended to seal the bushing arrangement 10 against, for example, a centering pin (not shown).

[0043] Both the outer bushing 12 and the inner bushing 14 are rotationally symmetric bodies.

[0044] The inner bushing 14 can be supported on the outer bushing 12 or its inner circumferential surface 26 via the section 36 projecting towards the outer bushing 12, both in the case of bending loads and in the case of deflections in the radial direction.

[0045] Fig. 4 shows an enlarged detail view of detail Z in Fig. 3.

[0046] From the enlarged view according to Fig. Figure 4 makes it clear that the recess 20 includes both the sealing lip 18 and the section 32 running parallel to the central axis M (see also Fig. 3) radially surrounds the inner bushing 14. The recess 20 extends almost to the projecting section 36 of the inner bushing 14, i.e., the recess 20 ends approximately at the level of the curved section 34. The projecting section 36 limits the recess 20 in the elastomer body 16 in the axial direction.

[0047] An elastomer layer of the elastomer body 16 on the inner circumferential surface 26 of the outer bushing 12 is approximately as thick in the area of ​​the recess 20 as the elastomer layer between the end surface 46 of the preceding section 36 and the inner circumferential surface 26 of the outer bushing 12.

[0048] The sealing lip 18 extends over a relatively large area of ​​the end face 22, i.e. a small area of ​​the end face 22 is not covered by the sealing lip 18 or the elastomer body 16.

[0049] From a synthesis of Fig. Figures 1 to 4 show that the recess 20 radially surrounds the sealing lip 18 and the inner bushing 14 up to the transition of section 32 into section 34. This mechanically decouples the sealing lip 18 from the outer bushing 12. Due to the recess 20, the sealing lip 18 can follow the movement of the inner bushing 14 under bending loads, effectively preventing the sealing lip 18 from lifting off the inner bushing 14 and, for example, off a centering pin (not shown).

[0050] A further embodiment of the present invention is described below. The same reference numerals are used for identical and equivalently functioning components, but preceded by the number "1".

[0051] Fig. Figure 5 shows a perspective view of the bushing arrangement 110 according to a second embodiment of the invention.

[0052] The bushing arrangement 110 comprises an outer bushing 112 and an inner bushing 114, which are connected to each other via an elastomer body 116. A sealing lip 118 is formed on the elastomer body 116, which abuts the inner bushing 114 in the axial direction.

[0053] Fig. Figure 6 shows a sectional view of the bushing arrangement 110, including the axle.

[0054] Compared to the one relating to the Fig. In the embodiment described in sections 1 to 4, the outer surface 128 of the inner bushing 114 has a different contour. The inner bushing 114 in this embodiment has end faces 122 and 124 that are very thin in the radial direction, i.e., smaller, compared to the embodiment described above.

[0055] Starting from the end face 122, the inner bushing 114, viewed axially, has a linear section 148 extending at an angle to the central axis M, to which a curved section 150 adjoins. The curved section 150 transitions into a section 152 projecting towards the outer bushing 112. The projecting section 152 is connected via the curved section 154 to a linear section 156, which extends at an angle to the central axis M of the bushing arrangement 110. In other words, according to this embodiment, the inner bushing 114 is provided with inclined sections 148 and 156 and considerably smaller end faces 122 and 124.

[0056] The recess 120 extends axially from an axial end of the outer bushing 112 into the elastomer body 116. The recess 120 radially surrounds the sealing lip 118 and the section 148 of the inner bushing 114, i.e., the section 148 of the axial extension of the inner bushing 114.

[0057] Fig. Figure 7 shows a sectional view of the bushing arrangement 110. The cylindrical surface 128 of the inner bushing 114 has the inclined section 148, the curved section 150, the section 152 projecting towards the outer bushing, the curved section 154 and the section 156 angled to the central axis M or running obliquely.

[0058] Out of Fig. Figure 7 now clearly shows that the recess 120 radially surrounds the sealing lip 118 and the section 148 of the inner bushing 114. The inner bushing 114 can be supported on the inner circumferential surface 126 of the outer bushing 112 via the projecting section 152 or its surface 158 and the elastomeric body 116. The elastomeric body 116 completely covers the outer surface 128 of the inner bushing 114.

[0059] As in the first embodiment, a thin elastomer layer of the elastomer body 116 spans the area of ​​the inner circumferential surface 126 of the outer bushing 112 in which the inner bushing 114 and the sealing lip 118 are not located. In the area of ​​the inner circumferential surface 126 in which the inner bushing 114 is located, the elastomer body 116 connects the outer surface 128 of the inner bushing 114 with the inner circumferential surface 126 of the outer bushing 112.

[0060] Fig. Figure 8 shows an enlarged partial view of detail Z in Fig. 7.

[0061] In Fig. Figure 8 shows the chamfered section 148 of the outer surface 128 of the inner bushing 114.

[0062] The recess 120 extends axially into the elastomer body 116 to such an extent that it radially surrounds section 148 of the outer surface 128 of the inner bushing 114. The recess 120 extends axially approximately to the transition of the inclined section 148 into the curved section 150, or ends at this transition.

[0063] This decouples the sealing lip 118 from the outer bushing 112. Due to the recess 120, the sealing lip 118 can follow the movement of the inner bushing 114 under bending loads, and lifting of the sealing lip 118 from the inner bushing 114 can be effectively prevented.

Claims

[1] Bushing arrangement (10) for centering two shaft sections to be joined, comprising: - at least one external socket (12), and - at least one inner bushing (14) arranged radially inwards of the at least one outer bushing (12), wherein the at least one outer bushing (12) and the at least one inner bushing (14) are connected via at least one elastomer body (16) on which at least one sealing lip (18) is formed, wherein at least one circumferential recess (20) is formed in the elastomer body (16) which extends from an axial end of the bushing arrangement (10) into the elastomer body (16) such that the at least one recess (20) extends radially around the at least one sealing lip (18) and around at least one section (32) of the axial extension of the inner bushing (12), characterized by , that the sealing lip (18) and the inner bushing (14) are arranged at an axial end region of the outer bushing (12). [2] Bushing arrangement (10) according to claim 1, characterized by , that the at least one recess (20) in the elastomer body (16) extends at least sectionally between the outer surface (28) of the inner bushing (14) and the inner circumferential surface (26) of the outer bushing (12). [3] Bushing arrangement (10) according to claim 1 or 2, characterized by , that an axial end region (30) of the at least one recess (20) is enclosed radially between the inner bushing (14) and the outer bushing (12). [4] Bushing arrangement (10) according to one of claims 1 to 3, characterized by , that at least one inner bushing (14) has a circumferential section (36) projecting towards the outer bushing (12). [5] Bushing arrangement (10) according to claim 4, characterized by , that the at least one recess (20) in the elastomer body (16) extends to the section (36) of the at least one inner bushing (14) projecting towards the outer bushing (12). [6] Bushing arrangement (10) according to one of the preceding claims, characterized by , that at least one recess (20) extends substantially parallel to the inner circumferential surface (26) of the outer bushing (12) into the elastomer body (16). [7] Bushing arrangement (10) according to one of the preceding claims, characterized by , that the outer surface (28) of the inner bushing (14), viewed in the axial direction, comprises a section (32) extending parallel to the central axis, which is connected via a curved section (34) to the section (36) projecting towards the outer bushing (12), wherein a further curved section (38) adjoins the projecting section (36), which transitions into a section (40) extending parallel to the central axis (M) of the bushing arrangement (10), wherein a chamfer (42) is provided at each of the axial ends of the inner bushing (14). [8] Bushing arrangement (110) according to any one of claims 1 to 6, characterized by, that the outer surface (128) of the inner bushing (114), viewed in the axial direction, comprises a linear section (148) extending at an angle to the central axis (M), to which a curved section (150) is attached, which transitions into the section (152) projecting in the direction of the outer bushing (112), wherein the projecting section (156) is connected via a curved section (154) to a linear section (150) extending at an angle to the central axis (M) of the bushing arrangement (10). [9] Bushing arrangement (10) according to one of the preceding claims, characterized by , that the outer surface (28) of the inner bushing (14) is completely surrounded by the elastomer body (16). [10] Bushing arrangement (10) according to one of the preceding claims, characterized by , that the elastomer body (16) covers the end faces (22, 24) of the inner bushing (14) at least partially. [11] Bushing arrangement (10) according to one of the preceding claims, characterized by , that the inner circumferential surface (26) of the outer bushing (12) is completely covered by the elastomer body (16). [12] Bushing arrangement (10) according to one of the preceding claims, characterized by , that the at least one recess (20) in the at least one elastomer body (16) surrounds radially to approximately between 10 and 40% of the axial extent of the inner bushing (14). [13] Centering device with a bushing arrangement (10, 110) according to one of claims 1 to 12. [14] Torque transmission device with a bushing arrangement (10, 110) according to any one of claims 1 to 12.

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