WO2013029638A1

WO2013029638A1 - Rolling bearing arrangement with balls and cylindrical rollers integrated in a hub of a vehicle wheel

Info

Publication number: WO2013029638A1
Application number: PCT/EP2011/004335
Authority: WO
Inventors: Laurens Verhulst
Original assignee: Aktiebolaget Skf
Priority date: 2011-08-29
Filing date: 2011-08-29
Publication date: 2013-03-07

Abstract

The invention relates to a rolling bearing arrangement (1) for a hub of a vehicle wheel. To minimize the friction of the bearing when using a bearing arrangement of this type the rolling bearing arrangement (1) comprises three rolling bearings (2, 3, 6) to support a first vehicle part (4) such as a wheel hub relatively to a second vehicle part (5) such as a flanged outer ring. Each rolling bearing (2, 3) comprises a first raceway (2', 3', 6') and a second raceway (2", 3", 6") for rolling elements (2"', 3"', 6"') located between the respective raceways. The first rolling bearing (2) is an angular contact ball bearing (ACBB). The first raceway (2') of the angular contact ball bearing (2) and the first raceway (3') of the second rolling bearing (3) are machined directly into the first vehicle part (4) and the second raceway (2") of the angular contact ball bearing (2) and the second raceway (3") of the second rolling bearing (3) are machined directly into the second vehicle part (5). The first raceway (6') of the third rolling bearing (6) is machined directly into a face side (7) of the second vehicle part (5) and the second raceway (6") of the third rolling bearing (6) is arranged at or in an auxiliary ring (8) which is connected with the first vehicle part (4). The second rolling bearing (3) is e.g. a cylindrical roller bearing and the third rolling bearing (6) is e.g. a thrust ball bearing having a larger pitch circle diameter than the cylindrical roller bearing.

Description

ROLLING BEARING ARRANGEMENT WITH BALLS AND CYLINDRICAL ROLLERS INTEGRATED IN A HUB OF A VEHICLE WHEEL

Technical Field

The invention relates to a bearing arrangement for a hub of a vehicle, wherein the bearing arrangement has at least a first roller bearing and a second roller bearing to support a first vehicle part relatively to a second vehicle part, wherein each roller bearing has at least one first raceway and at least one second raceway for rolling elements and wherein the rolling elements are located between the respective raceways.

Background

Such a bearing arrangement is known for example from WO 2009/040001 Al. Here, two cylindrical roller bearings are arranged at axial ends of the bearing arrangement. In between the two cylindrical roller bearings two thrust bearings are arranged which are ball bearings. The bearing rings have an reshaped form in the radial cross section; each L-shaped element forms a raceway for one of the cylindrical roller bearings and one of the thrust bearings. So a compact design is obtained. Furthermore, it is aimed to reduce the friction in the bearing arrangement while keeping a high degree of stiffness of the bearing arrangement.

It has been found that the friction of such a bearing arrangement is still too high when being used in the field of vehicles. Here, the reduction of friction in the bearings is a precondition to further reduce the amount of the required gasoline and to reduce the pollutant emission.

It is an o bj e c t of the invention to propose a design for a bearing arrangement which allows to further reduce the friction in the bearing arrangement. Furthermore, a stiff arrangement should be obtained which experiences minimal deformation under load. Finally, the production of the bearing arrangement should be easy and should be possible with part which can be produced in a simple way; so, existing production facilities should be usable for the production of the required components of the bearing arrangement.

Summary of the invention

A s o l u t i o n according to the invention is characterized in that the first raceway of the first roller bearing and the first raceway of the second roller bearing are machined directly into the first vehicle part and wherein the second raceway of the first roller bearing and the second raceway of the second roller bearing are machined directly into the second vehicle part, wherein the first bearing is an angular contact ball bearing, wherein a third roller bearing is arranged, wherein the third roller bearing has a first raceway and a second raceway between which rolling elements are arranged, wherein the first raceway of the third roller bearing is machined directly into a face side of the second vehicle part and wherein the second raceway of the third roller bearing is arranged at or in an auxiliary ring which is connected with the first vehicle part.

The first vehicle part is preferably a rotating hub element which bears a vehicle wheel, the second vehicle part is preferably a stationary housing element. The auxiliary ring can be arranged at one axial end of the first vehicle part. This ring can be fixed to the first vehicle part by means of a deformed part of the first vehicle part. The deformed part of the first vehicle part is preferably produced by an orbital forming process. The auxiliary ring may also be fixed to the first vehicle part by means of a screw connection, a welded or brazed connection or any other suitable joining technique.

The auxiliary ring can be arranged with a bore section on a cylindrical section of the first vehicle part. It can have a rim section forming an axial stop for the rolling elements of the second rolling bearing.

The second roller bearing is preferably a cylindrical roller bearing.

The cylindrical roller bearing is preferably designed to carry radial loads only. Beneficially, the bearing arrangement is designed in such a way that the resulting load point runs through the middle of the cylindrical roller bearing. This minimizes the friction during use.

The third roller bearing is preferably a thrust ball bearing. To minimize friction on the one hand and to deliver a high degree of stability and stiffness on the other, it is preferred that the radius of the first raceway of the second roller bearing is below 70 % of the radius of the center of the rolling elements of the third roller bearing. This has a positive effect on the friction situation in the bearing arrangement.

The pitch diameter of the third roller bearing is for the same reason preferably at least 125 % of the pitch diameter of the second roller bearing. The first vehicle part can have a mounting flange for a vehicle wheel. The second vehicle part can have a mounting flange for the connection with an adjacent vehicle part.

The advantages of the proposed bearing arrangement are basically a low friction in the arrangement, while a compact design is obtained. Furthermore, existing production lines and usual manufacturing machinery can be used to produce the required components of the bearing arrangement.

The main focus of the present invention is to supply a bearing arrangement for a hub of a vehicle which has a low friction. Also, the producibility of the bearing arrangement is an important aspect of the invention. The bearing arrangement allows the use of existing and usual production facilities to manufacture the required parts of the arrangement. The radial and axial loads are carried by specific bearings within the bearing arrangement. For carrying of radial loads the cylindrical roller bearing (second bearing) is employed. Preferably, the cylindrical roller bearing carries all radial load, but some can also be taken up by the first bearing being an annular contact ball bearing (ACBB). For carrying axial loads the third roller bearing is used (together with the angular contact ball bearing). Friction is hereby reduced to a minimum. Line contact between the raceways and the rollers - as in the case of cylindrical roller bearings - produce typically a lower friction than point contact - as in the case of thrust ball bearings.

The first bearing being an angular contact ball bearing can transmit radial and axial loads and is arranged adjacent to the wheel which is supported by the bearing arrangement. This bearing guarantees a high degree of stability and stiffness especially during cornering (driving of a curve).

It is aimed that the load point of the resulting forces being transferred by the bearing arrangement runs exactly through the middle of the second bearing, i. e. the cylindrical roller bearing. In this case the second bearing (cylindrical roller bearing) will carry the biggest part of the radial load. This will result in a lower friction.

The proposed concept is preferably employed for inner ring rotation; but the concept can of course also be used for outer ring rotation. The first roller bearing, i. e. the angular contact ball bearing, maintains the stability during cornering while the third roller bearing carries the axial loads; the second roller bearing being preferably a cylindrical roller bearing carries the radial loads only. The pitch diameter of the second roller bearing is relatively small to keep speed of the rolling elements low resulting in a low friction. The pitch diameter of the third roller bearing is relatively big to give the bearing a high stiffness especially during cornering (i. e. during driving of curves). A steel inner ring with a mounting flange and a steel outer ring are preferably used. The auxiliary ring is preferably made from steel, too.

Brief description of the drawings

The drawings show an embodiment of the bearing arrangement according to the invention.

Fig. 1 shows a cross sectional view of a bearing arrangement according to an embodiment of the invention and

Fig. 2 shows the corresponding perspective view of the bearing arrangement, in a partially broken depiction.

Detailed description of the invention

In the figures a bearing arrangement 1 is shown which is used as a hub bearing in a vehicle (car or truck).

The bearing arrangement 1 has in total three bearings, i. e. a first roller bearing 2 which is an angular contact ball bearing (ACBB), a second roller bearing 3 which is a cylindrical roller bearing and a third roller bearing 6 which is a thrust ball bearing. Each bearing 2, 3, and 6 has a first raceway 2', 3', and 6' and a second raceway 2", 3", and 6". Between the respective raceways, rolling elements 2" ', 3"', and 6"' are located. By this bearing arrangement 1 a first vehicle part 4 being a rotating hub element is supported relatively to a second vehicle part 5, which in this example is a bearing outer ring.

The first raceway 2' of the first roller bearing 2 and the first raceway 3 ' of the second roller bearing 3 are both machined directly into the first vehicle part 4. Also, the second raceway 2" of the first roller bearing 2 and the second raceway 3 " of the second roller bearing 3 are machined directly into the second vehicle part 5.

The first raceway 6' of the third roller bearing 6 is also machined directly into the second vehicle part 5; more specifically it is machined into a face side 7 of the second vehicle part 5.

The second raceway 6" of the third roller bearing 6 is arranged in an auxiliary ring 8 which is connected with the first vehicle part 4. The auxiliary ring 8 has a bore section 10 which fits to a cylindrical section of the first vehicle part 4. As can be seen from the figures, the auxiliary ring 8 is axially fixed with the first vehicle part 4 by a deformed part 9 of the material of the part 4, i. e. by orbital forming of the axial end of the vehicle part 4. Thus, the auxiliary ring 8 is firmly connected with the vehicle part 4. Furthermore, the auxiliary ring 8 has a rim section 12 which establishes an axial stop for the cylindrical rollers 3"' when the arrangement is assembled.

The first vehicle part 4 has a mounting flange 13, the second vehicle part 5 has a mounting flange 14. Looking preferably now at figure 2 it can be seen that the cylindrical roller bearing 3 and specifically its first raceway 3' has a radius τ_\. The rolling elements (balls) 6'" of the third roller bearing 6 are arranged with their center on a radius r₂. Furthermore, the pitch diameter Di of the second roller bearing 3 and the pitch diameter D₂ of the third roller bearing 6 are noted.

To minimize friction in the bearing arrangement as much as possible specific ratios for the mentioned parameters are preferred.

The radius r of the first raceway 3' of the second roller bearing 3 is preferably below 70 % of the radius r₂ of the center of the rolling elements 6'" of the third roller bearing 6. Also, it is preferred that the pitch diameter D₂ of the third roller bearing 6 is at least 125 % of the pitch diameter D_! of the second roller bearings 3.

Thus, friction in the bearing arrangement can be further reduced.

Reference Numerals:

1 Bearing arrangement

2 First roller bearing

2' First raceway

2" Second raceway

2"' Rolling element

3 Second roller bearing

3' First raceway

3" Second raceway

3"' Rolling element

4 First vehicle part

5 Second vehicle part

6 Third roller bearing

6' First raceway

6" Second raceway

6'" Rolling element

7 Face side

8 Auxiliary ring

9 Deformed part

10 Bore section

1 1 Cylindrical section

12 Rim section

13 Mounting flange

14 Mounting flange Radius of the first raceway of the second roller bearing Radius of the center of the rolling elements of the third roller bearing

Pitch diameter

Claims

Patent Claims:

Bearing arrangement (1) for a hub of a vehicle, wherein the bearing arrangement (1) has at least a first roller bearing (2) and a second roller bearing (3) to support a first vehicle part (4) relatively to a second vehicle part (5), wherein each roller bearing (2, 3) has at least one first raceway (2', 3') and at least one second raceway (2", 3") for rolling elements (2'", 3"') and wherein the rolling elements are located between the respective raceways, characterized in that the first raceway (2') of the first roller bearing (2) and the first raceway (3') of the second roller bearing (3) are machined directly into the first vehicle part (4) and wherein the second raceway (2") of the first roller bearing (2) and the second raceway (3") of the second roller bearing (3) are machined directly into the second vehicle part (5), wherein the first bearing (2) is an angular contact ball bearing (ACBB), wherein a third roller bearing (6) is arranged, wherein the third roller bearing (6) has a first raceway (6') and a second raceway (6") between which rolling elements (6"') are arranged, wherein the first raceway (6') of the third roller bearing (6) is machined directly into a face side (7) of the second vehicle part (5) and wherein the second raceway (6") of the third roller bearing (6) is arranged at or in an auxiliary ring (8) which is connected with the first vehicle part (4).

2. Bearing arrangement according to claim 1, characterized in that the first vehicle part (4) is a rotating hub element which bears a vehicle wheel.

3. Bearing arrangement according to claim 1, characterized in that the second vehicle part (5) is a stationary housing element.

4. Bearing arrangement according to one of claims 1 to 3, characterized in that the auxiliary ring (8) is arranged at one axial end of the first vehicle part (4).

5. Bearing arrangement according to one of claims 1 to 4, characterized in that the auxiliary ring (8) is fixed to the first vehicle part (4) by means of a deformed part (9) of the first vehicle part (4).

6. Bearing arrangement according to claim 5, characterized in that the deformed part (9) of the first vehicle part (4) is produced by an orbital forming process.

7. Bearing arrangement according to one of claims 1 to 6, characterized in that the auxiliary ring (8) is arranged with a bore section (10) on a cylindrical section (1 1) of the first vehicle part (4).

8. Bearing arrangement according to one of claims 1 to 7, characterized in that the auxiliary ring (8) has a rim section (12) forming an axial stop for the rolling elements (3"') of the second rolling bearing (3).

9. Bearing arrangement according to one of claims 1 to 8, characterized in that the second roller bearing (3) is a cylindrical roller bearing.

10. Bearing arrangement according to claim 9, characterized in that a load point of the bearing arrangement runs through the middle of the cylindrical roller bearing (3).

11. Bearing arrangement according to one of claims 1 to 10, characterized in that the third roller bearing (6) is a thrust ball bearing.

12. Bearing arrangement according to one of claims 1 to 11, characterized in that the radius ( ) of the first raceway (3') of the second roller bearing (3) is below 70 % of the radius (r₂) of the center of the rolling elements (6"') of the third roller bearing (6).

Bearing arrangement according to one of claims 1 to 12, characterized in that the pitch diameter (D₂) of the third roller bearing (6) is at least 125 % of the pitch diameter (Dj) of the second roller bearings (3).

Bearing arrangement according to one of claims 1 to 13, characterized in that the first vehicle part (4) has a mounting flange (10) for a vehicle wheel.

15. Bearing arrangement according to one of claims 1 to 14, characterized in that the second vehicle part (5) has a mounting flange (11) for the connection with an adjacent vehicle part.