WO2009040172A1

WO2009040172A1 - Device for compensating axial thermal expansion of a roller bearing arrangement

Info

Publication number: WO2009040172A1
Application number: PCT/EP2008/060324
Authority: WO
Inventors: Jürgen OSTERLÄNGER; Norbert Radinger; Tomas Smetana; Johann-Paul Stemplinger
Original assignee: Schaeffler Kg
Priority date: 2007-09-25
Filing date: 2008-08-06
Publication date: 2009-04-02
Also published as: DE102007045655A1

Abstract

The invention relates to a device for compensating axial thermal expansion of a roller bearing arrangement having a bearing ring (6) with a receptacle space for a thermal expansion element (10). In order to provide a compensation device which, while having a simple and cost-effective design, also permits the use of a thermal expansion element made of inexpensive material with relatively low durability and/or relatively low temperature coefficient, the bearing ring (6) is composed of two partial bearing rings (6a, 6b). In this context, the first partial bearing ring (6a) has a roller body running face (7), and the second partial bearing ring (6b) has an outer lateral face (13). The partial bearing rings (6a, 6b) bound the receptacle space (21) between them and can be displaced relatively to one another at least in the axial direction (A) owing to thermally induced changes in volume of the thermal expansion element (10).

Description

Name of the invention

Device for compensating for axial thermal expansion of a rolling bearing assembly

description

Field of the invention

The invention relates to a device for compensating for axial thermal expansion of a rolling bearing assembly with a bearing ring having a receiving space for a thermal expansion element.

Background of the invention

In the case of machine elements which consist of materials with different thermal expansion or with different temperature coefficients, different relative changes in length (axial thermal expansion) and thus changes in distance occur with changing operating temperatures. This phenomenon is particularly undesirable in high-speed assemblies where precise storage is required, such as automotive differentials or transfer cases. As a rule, in a motor vehicle transmission, the transmission housing is made of die-cast aluminum; The gear shafts made of steel are mounted by means of a tapered roller bearing. Here, the approximately twice as high thermal expansion of the aluminum housing in comparison to the steel shafts significantly noticeable and changes the set preload or the set bearing clearance of the bearings. This leads to reduced bearing life, at best to an axial wave shock to non-ideal meshing and noise.

To compensate for these effects, from the US Patent 5,028,152 devices of the type mentioned above are known in which in a bearing ring a circumferential recess is formed, in which a thermal expansion element in the form of a Dehnungshngs is used, on the other hand is supported on a shoulder of a transmission housing.

The expansion ring must be made of high-quality material, which has the highest possible temperature coefficient and a high resistance to aggressive external operating conditions - especially a high oil resistance. Therefore, the strain rings of the known device are preferably made of a marketed under the trade name VITON ^® from DuPont elastomer. This material is relatively expensive.

Object of the invention

Against this background, the object of the present invention is to provide a compensation device, which also allows the use of a thermal expansion element made of inexpensive material with lower resistance and / or lower temperature coefficient with a simple and inexpensive construction.

Description of the invention

This object is achieved by a device with the features of claim 1.

Accordingly, the bearing ring is composed of two bearing part rings, wherein the first bearing part ring has a rolling body tread and the second bearing part ring forms an outer surface of the rolling bearing assembly, wherein the bearing part rings between the receiving space between them and encapsulate the outside and wherein the bearing part rings due to thermally induced VoIu- menänderung of the thermal expansion element are displaceable relative to each other at least in the axial direction.

Under outer circumferential surface of the rolling bearing arrangement is within the scope of the invention Understand the standing in contact with the machine elements to be stored surface, so usually the cylindrical outer surface, with which the camp sits eg in a bearing bore, or the cylindrical surface of the bearing inner bore, in which, for example, a shaft to be stored is taken.

An essential advantage of the invention consists in the fact that the bearing part rings form an encapsulated receiving space in which the thermal expansion element against external influences is largely protected and sealed off accommodated. This can be used for the device according to the invention, a thermal expansion element made of a much cheaper material, such as thermoplastic elastomer, with significantly lower resistance to external influences, in particular low oil resistance.

Another significant advantage of the device according to the invention is that a pre-assembled and transportable mounting unit is created, which can be easily handled during final assembly.

The inventive design of the device also allows to optimize the recess and thus the axial extent of the thermal expansion element with respect to the axial thermal expansion. In other words, a ring or a sleeve with a comparatively small wall thickness or a small radial extent and a correspondingly long axial extent can be used as the thermal expansion element. This leads to the additional advantage that the material used for the thermal expansion element, for example, thermoplastic elastomers can be used, which have a lower thermal expansion. For example, materials known by the trade names Hytrel, Elastollan, TPSiV or Zeotherm may be used.

Due to the dimensions of the first or second bearing part ring, the fit or the seat of the second bearing part ring can be designed on the first bearing part ring become. In addition, a slight radial excess of the thermal expansion element may be provided, so that when mounting the rolling bearing assembly, an additional radial pressure is exerted, for example, from the outer bearing part ring on the inner bearing part ring. In the assembled mounting position, the two bearing rings are then fixed, for example, by means of a corresponding interference fit.

An installation-technically preferred development of the invention provides that the one bearing part ring extends in the axial direction over the entire length of the other bearing part ring.

A preferred embodiment of the invention with regard to the compensation efficiency provides that the one bearing part ring has a peripheral recess in which the thermal expansion element is at least partially received, and that the other bearing part ring completely covers this recess.

The bearing part rings may preferably be connected to each other at least at one point. In terms of manufacturing technology, the first bearing part ring is preferably a separate outer sleeve.

A further optimization of the compensation efficiency can be achieved according to a further preferred embodiment of the invention by limiting the bearing part rings a conical receiving space.

Advantageously, the bearing part rings may have an approximately L-shaped cross-section.

Structurally preferred, the bearing part rings on side walls which are connected to the respective other bearing part ring, that the bearing part rings can move axially and radially relative to each other while the receiving space remains encapsulated to the outside.

According to an advantageous embodiment of the invention is between a La- gerteilring and the receiving space arranged a separate intermediate sleeve. This embodiment has the advantage that standard bearings can be used and the compensation device forms a separate unit. In addition, in this embodiment, no weakening of the actual bearing ring to accept. This embodiment is particularly suitable for highly stressed bearing assemblies or for the subsequent retrofitting of rolling bearings.

According to an advantageous embodiment of the invention, a piston between the bearing part ring and the thermal expansion element is arranged within the Kapse-, which transmits compressive forces in the axial direction. As a result, thermal flow and unwanted setting of the thermal expansion element are particularly well prevented. In addition, the piston can additionally act sealingly, so that it is prevented that material of the thermal expansion element can escape or flow in any gaps between the outer sleeve and the bearing-side ring.

In terms of manufacturing technology, according to a further advantageous embodiment of the invention, at least one edge region of one bearing part ring is bent over in order to be supported on one end side of the other bearing part ring. The other, in the axial direction opposite edge region of a bearing ring part can be caulked for transport or assembly facilitation.

An advantageous development of the invention provides that the edge region of the one bearing part ring is axially stepped, wherein the step with a substantially radially extending step portion on the inside in contact with the thermal expansion element. The step-like design of the edge region forms a defined contact surface, to which the thermal expansion element can directly transmit the compensation forces that arise as a result of its thermal expansion. This design is particularly suitable for cases in which a piston is dispensed with. Brief description of the drawings

Further advantages and aspects of the invention will become apparent or in addition from the following description of the invention with reference to the accompanying drawings. Showing:

Figure 1 is a perspective view of a partial longitudinal section of a tapered roller bearing with a device according to the invention;

Figure 2 is a perspective exploded view of components of the arrangement of Figure 1;

3 is a perspective view of a partial longitudinal section of a tapered roller bearing with a further device according to the invention;

FIG. 4 shows in perspective an exploded view of components of the arrangement according to FIG. 3;

Figure 5 is a perspective view of a partial longitudinal section of a

Tapered roller bearing with a further device according to the invention;

FIG. 6 shows in perspective an exploded view of components of the arrangement according to FIG. 5;

Figure 7 is a perspective view of a partial longitudinal section of a tapered roller bearing with a further device according to the invention;

FIG. 8 shows a longitudinal section through various operating situations of the device according to FIG. 7; FIG. 9 shows a comparative illustration of the axial force flow of the exemplary embodiments according to FIGS. 1 to 6.

Detailed description of the drawings

In the following description of the figures, identical or functionally identical elements are provided with the same reference numerals.

The illustrated in Figures 1 and 2, the first embodiment of an inventive device shows a designed as a tapered roller bearing per se known rolling bearing 1 with a bearing inner ring 2 with a tread 3. On the tread roll formed as a tapered rollers 4 rolls off in a bearing cage 5 are held. A bearing outer ring 6 consists of two bearing ring parts, a first bearing ring part 6a and a second bearing ring part 6b. The bearing ring part 6a has a running surface 7, also referred to as an outer running surface, on which the rolling elements 4 roll. In the outer casing, seen in the radial direction, of the bearing ring part 6a, a peripheral radial recess 8, also referred to as a groove, is provided. In the recess 8, an existing from an elastomer 9 thermal expansion element 10 is at least partially introduced. The thermal expansion element 10 is formed (see also FIG. 2) by a thin-walled ring or a sleeve. Their radial extent is very small compared to the axial extent.

The arrangement of the first bearing ring part 6a and the thermal expansion element 10 is completely surrounded by the second bearing ring part 6b in the axial direction A. The second Lageringteil 6b extends axially completely over the length of the first bearing ring portion 6a and surrounds it at least so far that the recess 8 is completely below it and completely covered. The Lagering- part 6b forms with its outer surface, the outer circumferential surface 13 of the bearing ring 6 and is connected at its rear end or edge portion 14 with the rear edge or web 15 of the bearing ring portion 6a. In the front, transmission-side area of the bearing ring 6b is based with its umgeboge- NEN or beaded edge 18 on the front side 19 of a Lagerbords 20 of the ring 6a from. The bearing ring parts 6a, 6b thus form in cooperation with the recess 8 a closed receiving space 21 which extends axially.

The two bearing ring parts 6a, 6b are designed in their outer dimensions so that there is a fit between them, which allows a sufficient Axialverschieblichkeit with a tight fit. The thermal expansion element 10 has a small radial excess, so that this generates an additional radial pressure force in the mounted state. Thereby, the outer bearing ring part 6b is held tightly on the inner bearing ring part 6a. In the state mounted in a bearing arrangement, a press fit holding the bearing ring parts 6a, 6b in their functional position can be provided. Separate fastening or holding parts between the bearing ring parts are thus not required during operation; they can at most be configured in the form of cross-shaped beads, beadings, latching noses or hooks in order to secure the bearing ring parts relative to one another during transportation.

To guide the bearing ring parts in the axial direction relative to each other serve their respective casserole or contact surfaces.

In order to transmit the desired extension of the temperature in the axial direction A and the axial force generated thereby as wear-free as possible for the material of the thermal expansion element 10 on the edge 18 and thus on the non-illustrated contact surface, for example, a transmission, an annular piston 22 is provided at in which the front end 23 of the thermal expansion element 10 is supported. With its rear end 24, the thermal expansion element is supported on the inside vertical wall of the web 15. Due to the considerable axial extent of the recess 8 and the encapsulation formed by the outer sleeve 12 in cooperation with the recess 8 - whose shielding capability is considerably increased by the piston 22 - can be relatively inexpensive as material for the thermal expansion element 10. be chosen because the material does not have to have very high mechanical resistance and a high temperature coefficient. This has an overall cost-reducing effect.

FIGS. 3 and 4 show a second embodiment of a device modified from the first embodiment. Here, the basic structure of the bearing 1 is unchanged and will therefore not be described again. However, the bearing part ring 30 is modified by having its front edge portion 32 has a double step 33. In this case, the stage is supported by its lower end region 34 on the end bearing shelf 20 of the ring 6a. The substantially horizontally extending step shoulder 35 rests on the lateral surface 36 of the ring 6 axially displaceable. A step section 38, which adjoins the stepped shoulder 35 at a rearward angle and acts substantially radially, acts as a counterstop for the thermal expansion element 10 in that the end 23 rests against the inner side 40 of the step section 38. In a thermally induced expansion of the thermal expansion element 10 in the bounded by the rings 6a and 6b receiving space 21 in the axial direction A, this immediately causes an axial displacement of the end portion 34, which can be supported for temperature compensation in a conventional manner to a non-illustrated gearbox side stop surface ,

Finally, FIGS. 5 and 6 show a further modification of a device according to the invention, in which a first bearing part ring 6a 'of a bearing outer ring 6' with a constant concentric, ie shoulder-free outer surface 41 is used. This has the advantage that the lateral surface does not need to be additionally processed. On the ring 6a 'a separate (inner) sleeve 42 is pushed, which has a flange 44 for the rear end 24 of the thermal expansion element 10 in the rear region. The sleeve 42 has a bend 46, with which it is supported on a recess 47 on the board 48 of the ring 6a '. Otherwise, the bearing part ring 30 described in detail in connection with FIGS. 3 and 4 is used and, with its vertical, radially extending step section 38, is used internally. side as a stop 39 for the other end 23 of the thermal expansion element 10th

7 shows in a perspective view a partial longitudinal section of a tapered roller bearing with a further device according to the invention, wherein the bearing outer ring 50 is designed as a split outer ring by two trained as metal sleeves bearing part rings 50a, 50b interlock. The partial rings are formed in their respective cross-section 51, 52 L-shaped. They are nested in such a way that they form a receiving space 53 between them and form an outward appearance. This has longitudinally tapering walls 56, 57 which are formed by the axial inner walls of the partial rings 50a, 50b. This results in a receiving space 53, which has a conical shape. The receiving space is provided with a material such as an elastomer (heat expansion member) 58, filled, one high thermal expansion coefficient (for example, VITON ^® with α = 1, 5 x 10 ^"4 x 1 / K) In the case of temperature-dependent expansion of the material moving. the rings 50a, 50b relative to each other, the walls of which, as indicated only schematically by cooperating mold elements (eg grooves and webs) provide a permanent and sealing contact.

FIG. 8 shows in longitudinal section two operating situations of the device according to FIG. 7 at a temperature of 20 [deg.] C. or of 120 [deg.] C. at a temperature of 20 [deg.] C. (see left-hand part of FIG. a bearing 60 with a device according to the invention is seated firmly with its bearing inner ring 61 on one end 62 of a shaft 63 to be supported. The bearing outer ring 50 is formed by second bearing part rings 50a, 50b as described above, wherein the second, outer part ring 50b is firmly seated in a bore 64 of an aluminum housing 66 is received. Between the partial rings, the thermal expansion element 58 in the receiving space 53 can be seen.

With an increase in the temperature to 120 ° C, the housing 66 axially and radially much more expanded than the shaft 63. Therefore, the results in the right part of Figure 8 - greatly exaggerated - expansion of the bore 64, with the result that the bearing assembly without temperature compensation would be taken only with play and thus any original bearing preload would be changed. The expansion of the thermal expansion element 58 leads to an increase in pressure in the receiving space 53, due to which the relatively movable bearing part rings 50a, 50b as indicated in the axial A and radial direction R, so that a resulting shift (arrow V) of the partial ring 50a to a compensation leads to these effects.

FIG. 9 shows the three exemplary embodiments described above in a longitudinal section, the arrow F symbolizing the force flow under axial load.

In the left part of Figure 9 (embodiment according to Figures 1 and 2), the power flow through the bearing inner ring 2, the rolling elements 4, the bearing outer ring 6, the thermal expansion element 10 and the annular piston 22 is shown schematically, this is about bearing ring 6b or its bend 18 outside supported on a housing section, not shown.

FIG. 9 shows in the middle region (according to the exemplary embodiments according to FIGS. 3 and 4) the basically same force flow via the bearing inner ring 2, the rolling elements 4, the bearing outer ring 6, the thermal expansion element 10, which, however, runs over the step 33 of the edge 32 of the partial ring 30 ,

In Figure 9 right of the first on the bearing inner ring 2, the rolling elements 4, the bearing outer ring 6 ', the thermal expansion element 10, the separate sleeve 42 and the gradation 33 extending force flow can be seen.

It can be seen that due to the relatively large axial extent of the receiving space 21 for the thermal expansion element 10, even with cost-effective materials, a magnitude relatively long extension and thus temperature compensation exists. In contrast, the required additional radial space of the device according to the invention very low. The devices according to the invention are also characterized by the fact that they require no additional axial space.

The separate bearing part rings form a reliably encapsulated receiving space 21 in a structurally and production-wise simple manner, so that no high resistance requirements with respect to external media must be placed on the material of the thermal expansion element 10.

The sealing essentially takes place via a steel / steel contact between the partial rings. Partial ring 6b or 30, together with the tapered roller bearing, can easily be inserted into an e.g. on the housing side provided receiving bore be pressed.

Although configurations are shown with arranged on the bearing outer ring temperature compensation devices in the embodiments, a realization on the bearing inner ring is conceivable in the same way.

LIST OF REFERENCE NUMBERS

roller bearing

Bearing inner ring

tread

rolling elements

Bearing cage, 6 'Bearing outer ring a, 6a ¹ Bearing ring b Bearing ring

tread

recess

Elastomer 0 thermal expansion element 2 outer sleeve 3 outer lateral surface 4 edge area v. 6b 5 Rear edge / bridge v. 6a 8 bent edge 9 end face 0 bearing board 1 receiving space 2 ring piston 3 front end v. 10 4 Rear end 0 Bearing ring 2 Border area 3 Level 4 End area 5 Step shoulder 6 Sheath b. 6 8 step section 9 stop inside in 38 40 inside v. 38

41 lateral surface v. 6a '

42 sleeve

44 flange

46 bend

47 recess

48 storage board v. 6a '

50 bearing outer ring

50a, 50b bearing rings

51, 52 cross section

53 recording room

56, 57 walls v. 53

58 thermal expansion element

60 bearings

61 bearing inner ring

62 end

63 wave

64 hole

66 aluminum housing

A axial direction

F arrow = power flow

R radial direction

V arrow

Claims

claims

1. Device for compensating axial thermal expansion of a rolling bearing assembly

- With a bearing ring (6) having a receiving space for a thermal expansion element (10),

characterized in that

- The bearing ring (6) consists of two bearing part rings (6a, 6b) is composed,

- wherein the first bearing part ring (6a) has a rolling body running surface (7) and the second bearing part ring (6b) forms an outer circumferential surface (13) of the rolling bearing assembly,

- Wherein the bearing part rings (6 a, 6 b) limit the receiving space (21) between them and encapsulate to the outside and

- Wherein the bearing part rings (6a, 6b) due to thermally induced volume changes of the thermal expansion element (10) at least in the axial direction (A) are displaceable relative to each other.

2. Apparatus according to claim 1, characterized in that

- The one bearing part ring (6b) in the axial direction (A) over the entire

Length of the other bearing part ring (6a) extends.

3. Apparatus according to claim 1 or 2, characterized in that

- A bearing part ring (6 a) has a circumferential recess (8) in which the thermal expansion element (10) is at least partially accommodated,

- And that the other bearing part ring (6b) completely covers this recess (8).

4. Device according to one of the preceding claims, characterized in that

- The bearing part rings (6 a, 6 b) are connected at least at one point with each other.

5. Device according to one of the preceding claims, characterized in that

- The first bearing part ring (6 a) is a separate outer sleeve.

6. Device according to one of the preceding claims, characterized in that

- The bearing part rings (50 a, 50 b) define a conical receiving space (53).

7. Device according to one of the preceding claims, characterized in that

- The bearing part rings (50 a, 50 b) have approximately L-shaped cross-section.

8. Device according to one of the preceding claims, characterized in that

- The bearing part rings (50 a, 50 b) side walls (56, 57) which cooperate with the respective other bearing part ring (50 b, 50 a) so that the bearing part rings (50 a, 50 b) can move axially and radially relative to each other during the receiving space (53) remains encapsulated.

9. Device according to one of the preceding claims, characterized in that - Between a bearing part ring (6 a ¹ ) and the receiving space (8), a separate intermediate sleeve (42) is arranged.

10. Device according to one of the preceding claims, characterized in that

- Between a bearing part ring (6b) and the thermal expansion element (10) in the axial direction (A) force-transmitting piston (22) is arranged net is.

11. Device according to one of the preceding claims, characterized in that

- At least one edge region (18) of a bearing part ring (6b) is bent to support one end face (19) of the other bearing part ring (6a).

12. Device according to one of the preceding claims, characterized in that

- The edge region (32) of a bearing part ring (6 b) is axially stepped, wherein a substantially radially extending step portion (38) on the inside in contact with the thermal expansion element (10).