WO2007068275A1

WO2007068275A1 - Bearing arrangement

Info

Publication number: WO2007068275A1
Application number: PCT/EP2005/013614
Authority: WO
Inventors: Jacobus Zwartz; Bernardus Gerardus Van Leeuwen
Original assignee: Ab Skf
Priority date: 2005-12-17
Filing date: 2005-12-17
Publication date: 2007-06-21

Abstract

The invention relates to a bearing arrangement (1) for a hub unit (2) of a driven or non-driven vehicle wheel end, especially of a truck or trailer, wherein a hub element (3) is supported relatively to a housing (4) by means of a bearing (5) with at least one rotating inner ring (6, 7), at least one stationary outer ring (8, 9) and rolling bodies (10, 11) between them, wherein the wheel hub element (3) is connected with the at least one inner ring (6, 7), wherein the at least one outer ring (8, 9) is connected with the housing (4), wherein at least one tire (29) is mounted on the hub unit (2) and wherein the bearing arrangement (1) is equipped with a seal unit system (30) for surveying the air pressure in the tire (29). To improve the system for surveying the air pressure in the tire, the invention is characterized in that an air conduit (31) of the system (30) for surveying the air pressure in the tire (29) is extending axially through the at least one inner ring (6, 7) of the bearing (5).

Description

Bearing Arrangement

Technical Field

The invention relates to a bearing arrangement for a hub unit of a driven or non-driven vehicle wheel end, especially of a truck or tractor/trailer.

Background

Bearing arrangements with a rotating outer ring are known to firmly mount a tire on a hub unit radially and axially relative to a housing. Often, two-row taper roller bearings in O-configuration are employed, which are mounted in the rotating cylindrically shaped bore of the housing of which the inner rings are pre-loaded locked on the stationary shaft with a locknut. The stationary shaft is a part of the chassis or suspension of the truck.

Summary of the invention

It has been found that existing systems for surveying the air pressure in the tire are not optimal when it comes to a concept with a bearing having a rotating inner ring and a stationary outer ring.

It is also desirable to design the bearing assembly together with the hub system so that one design can be used for different concepts. Especially, one concept is to use a quite wide tire but only one tire per hub unit ("Super Single Tires"), another concept is to use smaller tires but two tires ("Dual Tires") per hub unit. Furthermore, it has been found that due to the need to maintain the respective components of the system, e.g. the brake disc/unit, it is desirable to have a construction, which facilitates the assembly and disassembly to, for example, save costs for service works.

Therefore, it is an obj e ct of the invention to create an improved bearing arrangement according to a concept with a hub element with a bearing comprising a rotating inner ring and stationary outer ring, which allows improvements with regard to the mentioned aspects. All known functions, specifically the tire pressure control system, have to be maintained. Furthermore, it should become possible to adapt the bearing arrangement to different hub designs, i.e. dependently from the fact if a single tire or a dual tire is employed. Finally, the assembly and disassembly of the arrangement is aimed to become easier. Also sensors can be incorporated to monitor and control wheel-end functions e.g. rotational speed, vibration, temperature, load etc. For example an encoder sensor can be employed for transmitting the wheel rotational speed.

The hub element can be supported relative to a housing by means of a bearing with at least one rotating inner ring, at least one stationary outer ring and rolling bodies between them, wherein the wheel hub element is connected with the at least one inner ring, wherein the at least one outer ring is connected with the housing.

A solution according to the invention is characterized in that an air conduit of the system for surveying the air pressure in the tire is extending axially through the at least one inner ring of the bearing. Preferably, a second air conduit can connect one of the ends of the air conduit of the inner ring with the inner of the tire. Furthermore, a third air conduit can connect the other end of the air conduit of the inner ring with a pressure chamber, wherein the third conduit extends radially from the end of the air conduit of the inner ring through the inner ring or a part adjacent to the inner ring.

To ensure a high reliability of the system, the bearing arrangement can be characterized in that at least one seal unit is arranged at the end of a conduit.

So, a high level of safety can be guaranteed and it becomes very easy to survey the air pressure in the tire even when the conduit has to rotate with the inner ring. This can be an add-on device and can be incorporated with sensors, e.g. speed and/or load sensors to, for example, be linked to an ABS- brake system.

The at least one outer ring can be arranged in a cylindrically shaped bore of the housing and the at least one outer ring can axially be locked by connecting means relatively to the housing, wherein the connecting means comprise at least one recess in the outer circumference of the at least one outer ring and at least one fastener element which can be inserted and fixed in a bore in the housing, so that the end of the fastener element engages into the recess to axially lock the at least one outer ring relatively to the housing.

This radial locking device leaves new space for axial fixation means, e.g. direct or indirect fixation via a distance piece onto the suspension. With regard to the mentioned bore for the fastener element it should be noted that this includes a recess with a round or out of round cross section. Normally, the round cross section is preferred due to an easy fabrication. In spite of this, an out of round cross section (oval, rectangular, square, double circles, etc.) can have advantages when it comes to mounting of the fastener element in a defined orientation as it will become apparent later on.

Normally, it is preferred that the bore in the housing extends radially through the housing. An alternative concept has the bore in the housing extending under an angle to the radial direction through the housing. It is only important that the bore (or a respective recess) is arranged in the housing so that the fastener element interferes with the recess in the outer circumference of the outer ring to locate the outer ring of the bearing relatively to the housing.

A preferred embodiment comes up with a concept wherein the recess in the outer circumference of the at least one outer ring is a groove, running around the whole circumference of the at least one outer ring.

The fastener element can be fixed in its final position by means of a mechanical locking device, e.g. a screw or a cirlcip with a spring, e.g. a compressed rubber seal. For this the bore in the housing can be equipped with a thread for a screw.

The at least one recess in the outer circumference of the at least one outer ring can have a shape defining an undercut in axial direction of the at least one outer ring. With this concept the fastener element interfering into the recess has a good halt in the recess to ensure appropriate axial fixation of the outer ring relatively to the housing. The recess can be a groove with at least two adjacent rills which run around the whole circumference of the at least one outer ring wherein the fastener element can have a corresponding shape at its end contacting the rills. The at least one outer ring can comprise a plurality of adjacent rills. With this design it becomes very easily possible to axially fix a two-piece outer ring in the housing as will become apparent later on. The fastener element can be equipped with guide means which prevent a rotational movement of the fastener element around the axis of the bore in the housing. With this feature it is made sure that the mentioned rills will be exactly met when inserting the fastener element.

The bearing is preferably a two row bearing e.g. a roller or ball bearing or a combination of these, especially a two row taper roller bearing. The connecting means are preferably located between the raceways for the roller bodies in a minimum loaded or a non-loaded zone. Furthermore, the outer ring can be made as a single part which comprises two raceways for the roller bodies. An alternative solution has a bearing which comprises two outer rings, which are axially connected by the fastener element in the mounted state.

The bearing arrangement can also be characterized in that the housing is connected with a suspension and that a distance piece of defined axial extension is detachably arranged between the housing and the suspension.

According to a preferred embodiment the connection between the distance piece and the housing as well as the connection between the distance piece and the suspension is realized by means of screws or bolts.

So, it becomes possible to modularly employ the suggested bearing arrangement for single tire concepts as well as for twin tire concepts. As will be apparent later on with this design it becomes possible to easy adapt one bearing arrangement for another concept with regard to the width of the tire/tires. As mentioned, the connection between the distance piece and the housing as well as the connection between the distance piece and the suspension is realized by means of screws with or without the combination of a U-shaped clamp component.

Further preferred embodiments of the invention are defined in the claims.

Brief description of the drawings

The drawings show embodiments of the bearing arrangement according to the invention.

Fig. 1 shows a radial cross section of a side view of a bearing arrangement of a dual tire hub unit, consisting of a hub with a pre-loaded double row pre-assembled bearing unit, Fig. 2 shows a radial cross section of a bearing of the bearing arrangement consisting of a pre-loaded flanged hub with an integrated roller raceway and a separate roller / inner ring set, Fig. 2A shows a radial cross section of a bearing of the bearing arrangement having two inner rings and two outer rings, wherein a spacer ring is arranged between the two outer rings,

Fig. 3 shows a radial cross section of a one piece bearing outer ring of the bearing arrangement mounted in a housing, wherein the housing forms one piece with the suspension and wherein the inner rings are fixed by so called orbital forming, Fig. 4 shows a radial cross section of a split bearing outer ring of a part of a housing of a bearing arrangement, Fig. 4A shows a radial cross section of a corresponding bearing arrangement with a spacer ring between the two outer rings, Fig. 5 shows an enlarged view of locking means according to an alternative embodiment, Fig. 6 shows a detail of the arrangement according to fig. 4 in a specific embodiment for a one-part outer ring of the bearing, Fig. 7 shows an alternative design of the solution according to fig. 6, Fig. 8 shows the view "X" according to fig. 7, Fig. 9 shows a radial cross section of the bearing arrangement with a distance piece for a Super Single Tire application,

Fig. 10 shows a comparison of two bearing arrangements, one according to fig. 3 and one according to fig. 9,

Fig. 11 shows a schematic illustration of the flanged/bolt connection of the suspension with the housing in a combination with a U-shaped connection element,

Fig. 12 shows a hub unit with the bearing arrangement for a Super Single Tire wheel-end, equipped with an air routing as part of a tire pressure control system, Fig. 13 shows the bearing arrangement of the hub unit according to fig. 12 with the seal unit to create the air routing between the stationary and rotating parts as part of a tire pressure control system, Fig. 14 shows a perspective view of the bearing arrangement and seal unit according to fig. 13, Fig. 15 shows a sectional view of a seal unit with a part adjacent to the inner bearing ring with a first and a third air conduit as well as a pressure chamber, Fig. 16 shows a radial cross section of an arrangement similar to that of fig.

9 with a mounted distance piece and suitable for use for the single tire concept, Fig. 17 shows the arrangement according to fig. 16, but without mounted distance piece and suitable for use for the dual tire concept, Fig. 18 shows the bearing with the housing of the arrangement according to fig. 16 and 17, Fig. 19 shows the bearing with the housing (upper part of the figure) and the arrangement according to fig. 16 (lower part of the figure), Fig. 20 shows a wheel hub unit with the bearing arrangement according to fig. 16 for the single tire concept and Fig. 21 shows a wheel hub unit with the bearing arrangement according to fig. 17 for the dual tire concept.

Detailed description of the invention

Fig. 1 shows in radial cross section a wheel end bearing arrangement 1 preloaded and with rotating inner ring positioned with a radial interference fit of the stationary outer ring in a housing 4 according to one embodiment of the invention. The bearing arrangement 1 is employed to support a hub unit 2 relatively to the housing 4 forming one piece with the suspension 25 of a vehicle. A hub element 3 - here designed to be used for a dual tire concept - bears the wheel hub unit 2, wherein the hub unit 2 is fixed to the hub element 3, 3" by means of screws. A pre-loaded bearing 5 supports the hub element 3, 3" relatively to the housing 4, i. e. the hub element 3, 3" is rotatably arranged relatively to the housing 4 and kept in position radially and axially.

Fig. 2 shows an alternative arrangement in more detail but also with a bearing with rotating inner ring(s). As can be better seen in this figure the bearing 5 is a two-row taper roller bearing; other types of bearings can also be employed. The outer ring 8 of the bearing 5 has two raceways for two rows of taper rollers. One of the inner rings 6 is formed by an intermediate part 71 which has connection means 41 by which it is attached to the hub element 3 (see fig. 1). A raceway 39 is machined into this part. The other inner ring 7 is formed by a separate part which is connected with the intermediate part 71 by orbital forming, i. e. the right axial end of the intermediate part 71 is radially bent outwards to form a shoulder which keeps the inner ring 7 in its position. The inner ring 7 has the raceway 40 for the taper rollers.

It can also be seen in fig. 2 that a recess 14 is machined into the outer ring 8. Here, the recess 14 is a ring groove running around the whole circumference of the outer ring 8.

An alternative arrangement is depicted in fig. 2 A. Here the bearing 5 has two inner rings 6 and 7 as well as two outer rings 8 and 9. The inner rings 6, 7 are arranged on an intermediate part 71 which is connected by (not shown) screws to the hub unit 3. In distinction to fig. 2 the outer ring is not made as one piece but consists of the two rings 8 and 9 which are kept at a defined distance by a ring part 56 (spacer). In this case only the spacer 56 has the recess 14 which is used as described blow.

If the spacer 56 is of different material (e. g. aluminium) than the other parts of the bearing (e. g. steel) the pre-load can modify (raise) when the bearing warms up during operation.

As can be seen in fig. 3, the rotating inner rings are arranged on the intermediate part 71 as described above. The intermediate part 71 is fixed to the hub element 3 by means of connections means (screws) 41. At a flange 42 of the hub element 3 the wheel hub unit 2 (not shown in fig. 3), i. e. the vehicle wheel is attached (see fig. 1). The wheel hub, i. e. the hub unit 2 and/or the hub element 3, can suitably be made of cast iron or light metal like aluminum. Furthermore, the hub element 3 bears a brake disc 43. The brake disc 43 can have a defined axial position after assembly of the unit to fit to the respective floating disc brake caliper (not shown) or a floating brake disc can be employed in combination with a fixed disc brake caliper.

To facilitate the assembly and the disassembly of the unit, the arrangement is equipped as shown in one embodiment in fig. 4: The housing 4 has a cylindrically shaped bore 12 in which the pre-loaded bearing unit 5 is inserted with a radial interference fit and axially locked, i.e. the diameter of the cylindrically shaped bore 12 is substantially the same as the outer diameter of the outer rings 8, 9. When the bearing 5 is inserted into the cylindrically shaped bore 12 of the housing 4 the bearing 5 is axially fixed by one or more connecting means 13 positioned in minimum or non-loaded sections.

In the embodiment shown in fig. 4 the connecting means 13 consist of a bore 16 machined in radial direction into the housing 4. A thread 18 is machined into the bore 16. As mentioned earlier a recess 14, preferably a groove running around the whole circumference of the outer rings 8, 9, is machined in the outer circumference of the outer ring/rings 8, 9. After allocation of the bearing 5 and the outer rings 8, 9 respectively in the bore 12 a fastener element 15 is inserted in radial direction into the bore 16 in the housing 4. The fastener element 15 interferes into the recess as depicted in fig. 4. Consequently, an axial movement of the outer rings 8, 9 is prevented after the fastener element 15 is in its final position. To fix the element 15 in this position a screw 17 is screwed into the bore 16 and the fastener element 15 is pressed in contact with the recess 14. To prevent the infiltration of dirt and moisture into the region between the bore 12 and the outer rings 8, 9 the screw 17 is equipped with a seal 44 (O-ring seal) arranged in a ring groove at the outer circumference of the screw 17. An alternative design is depicted in fig. 4A. Here the arrangement corresponds to that one shown in fig. 2A. The at least one recess 14 is machined in the spacer 56 which keeps the two outer rings 8, 9 at a defined distance. As the bearing 5 is assembled in a pre-loaded manner, the spacer 56 is firmly fixed in its position between the two outer rings 8, 9, i. e. the spacer

56 is insofar axially and radially connected with the outer rings 8, 9. The spacer 56 is sealed to the outer rings 8, 9 similar like the screw 17 to the housing 4 with O-ring seals. The fastener element 15 engages with the recess 14 in the same way as describes in connection with fig. 4.

The fixation of the fastener element 15 can also be done in an alternative way as shown in fig. 5 as one example of different possibilities: Here, the housing 4 has the bore 16 in which the fastener element 15 is inserted to match with the at least one recess 14 in the outer circumference of the outer rings 8, 9. Further, a ring groove 18' is machined in the bore 16 fitting with the cross shape of a circlip 17'. Between the fastener element 15 and the circlip 17' a spring element 17" is mounted which presses the fastener element 15 down to the outer rings 8, 9. In this embodiment the spring element 17" is a belleville spring washer. Also an other spring element can be employed with spring back characteristics, e. g. a rubber or elastomer ring. The bore 16 is covered by a cap 49 which can be made form metal or a non-metal material.

In figures 6 and 7 details of the connecting means are apparent. In fig. 6 the outer ring 8, 9 has a ring groove 14 running around the whole circumference of the outer ring 8, 9 defining an undercut 19 so that the axial fixation of the outer rings 8, 9 relatively to the housing 4 is assured after insertion of the fastener element 15. In fig. 7 the recess 14 has a couple of rills 20. Correspondingly, the fastener element 15 has the respective profile to fit into the rills 20.

In the latter case of fig. 7 it is important, that the fastener element 15 has the correct position to find the rills 20 of the recess 14 when the fastener element 15 is inserted into the bore 16. Therefore, guide means 21 can be employed to make this sure.

The view "X" according to fig. 7 is depicted in fig. 8. The fastener element 15 has a nose 45 at one circumference position, which fits into a cutout 46 extending in axial direction of the bore 16. Consequently, the fastener element 15 can be inserted into the bore 16 in only one relative rotational position with respect to the axis 22 of the bore 16. Another possibility to ensure that the fastener element 15 is inserted into the bore 16 in the correct orientation is to machine the bore 16 and correspondingly the fastener element 15 in an out of round cross section, i. e. the bore 16 can have a round or a out of round cross section. Specifically, the bore 16 can have a cross section which is oval, rectangular, having two circles that mix, and the like.

It is an advantage of the invention that the described pre-loaded bearing arrangement is applicable for different concepts of wheel rims. In some applications it is desirable to have different concepts realized with basically the same bearing arrangement: One concept is a so called Super Single Tire wheel rim, the other is a dual tire wheel rim as explained above. In fig. 1 the dual tire concept is depicted. Fig. 12 shows the concept of only one tire, i. e. the Super Single Tire concept.

To have the possibility to change from one wheel end tire concept to the other a solution is suggested as depicted in fig. 9. Here the housing 4 is fixed to a suspension 25 not directly - as done for the concept with dual tires - but indirectly via a distance piece 26 to realize the single tire concept (see fig. 10: dual tire concept depicted in the upper drawing without distance piece 26, single tire concept shown in the lower drawing with distance piece 26). The distance piece 26 has a defined axial extension x which defines a certain axial position of the housing 4 relatively to the suspension 25. As can be seen in fig. 10 an axial reference position 47 is defined for one face side of the brake disc 43, which has to be kept. So by inserting the distance piece 46 between the housing 4 and the suspension 25 the hub unit can easily be converted from the dual tire concept to the single tire concept and vice versa, i.e. by taking out the distance piece 26 the concepts can be changed easily using the same drive shaft length as the splined bearing inner ring can be shifted over the splined drive shaft.

It should be noted that different hub elements 3', 3" are used for the two concepts (Super Single Tire or Dual Tire).

To facilitate the conversion from one wheel end tire concept to the other and to ensure a minimum number of required parts of the bearing arrangement the distance piece 26 is fixed with bolts or screws 27 and 28 respectively.

Another possibility of connecting the suspension 25 with the housing 4 and the distance piece 26 respectively is to use a connection element 50 as depicted in fig. 11. As can be seen in the sectional view of fig. 11 the connection element 50 has a U-shaped cross section. It covers flanges 51 and 52 which are located at the axial ends of the housing 4 or distance piece 26 and of the suspension 25 and takes up the major bending forces. The fixation is also done with bolts or screws 27 or 28. The connection element 50 can be designed as a two part assembly, each part covering 180° of the circumference of the flanges 51 and 52.

Figures 12 till 15 show in different views an integrated or add-on system 30 for surveying the air pressure in the inner 24 of a tire 29 mounted on the hub unit. Therefore three air conduits 31, 32 and 35 are arranged in the bearing arrangement 1. The first air conduct 31 is a pipe or bore arranged in the inner ring or inner rings 6, 7 of the bearing 5 which runs substantially in axial direction through the inner ring 6, 7. On one end 33 of the first air conduit 31 of the inner ring a second air conduit 32 is gastight attached to the conduit 31. As can be seen in fig. 12 and 13, this conduit 32 runs to the carrier plane which bears the tire and has a fluidic connection to the inner 34 of the tire 29. As can be seen in fig. 13 a third air conduit 35 is attached to the other end 36 of the air conduit 31. This conduit 36 is a bore in the inner ring 6, 7 or in an adjacent part 38, which is oriented radially and ends in a sealed pressure chamber 37. The pressure chamber 37 is composed of walls or parts adjacent to those walls of the inner ring 6, 7 and the outer ring 8, 9. As can be further seen there is a fourth conduit 48 which creates a gaseous connection between the pressure chamber 37 and a face side of the housing 4. Here, a pressure tube 55 can be fixed. It should just be mentioned that in fig. 13 a spline is visible at the inner circumference of the intermediate part 71 which is connected with the hub element 3. This spline cooperates with a spline at the end of a drive shaft (see fig. 16: reference numeral 57) which is not shown in fig. 13.

It is to be understood that suitable seal units or seal elements are arranged to seal the connection between the different conduits 31, 32, 35, 48. For this purpose integrated seal units can be employed as well as add-on units. So, it can be made sure that the air routing can be done without leakage. In fig. 15 the part 38 is depicted which is allocated adjacent to the inner ring 7 (not shown). The first air conduit 31 enters into the part 38 from the left hand side. A radial oriented bore forms the third air conduit 35 which is in fluidic communication with the first air conduit 31. At the outer radial end of the third air conduit 31 the pressure chamber 37 is allocated. Seals 53 and 54 seal the pressure chamber 37 against the environment.

Referring now to fig. 16, an arrangement is shown which is equipped with the distance piece 26 so that is used for the single tire concept, see fig. 20. A drive shaft 57 extends centrally through the suspension 25 and the housing 4 to reach the inner spline of the intermediate part 59 (part adjacent to the inner rings of the bearing 5). The drive shaft 57 has a corresponding spline at its axial end to form means 58 to establish a torque drive (torsional connection by a spline connection) between the drive shaft 57 and the intermediate part

59.

The housing 4 is equipped with a cylindrical bore 69 in one of its axial end regions. The diameter of this bore 69 fits to that one of a cylindrical outer circumference 70 of a support 67 formed by a hollow-cylindrical part. The support 67 is fixed with the suspension 25 at one axial end. This can be done by welding, especially friction welding. So₅ the housing 4 can axially slide on the support 67. Consequently, the housing 4 can be arranged in a desired relative axial position to the suspension 25. This allows that the housing 4 can be used quite easily for changing the concepts from single tire to dual tire and vice versa.

To establish the arrangement for use with a single tire application, the distance piece 26 with its axial extension x is located on the support 67 and the housing 4 is put on the support 67. The support 67 has a flange as well as the housing 4, see flange 72. So, bolts or screws 27 can be fixed so that a firm unit is obtained from suspension 25, support 67 and housing 4 with the preloaded bearing unit 5.

To fix the drive shaft 57 axially and relatively to the hub element 3 a fixation element 60 is detachably arranged at the one face end of the drive shaft 57. The fixation element 60 has a flange part and a screw 64 by which the axial fixation of the drive shaft 57 relatively to the hub element 3, 3' takes place, so that a defined axial position exists between the drive shaft 57 and the hub element 3.

If the arrangement according to fig. 16 - which is used to arrange a single tire 29 according to fig. 20 - has to be used to arrange a dual tire concept as depicted in fig. 21, the arrangement is employed as shown in fig. 17.

Here, the distance piece 26 has been taken out, so that the housing 4 could slide on the support 67 in the depicted position. Support 67 and housing 4 are again fixed by screws or bolts 27, so that a firm connection is given between the housing 4 and the suspension 25.

It should be noted that the drive shaft 57 has always the same axial length and always stays in the same axial position. As can be seen by comparison of figures 16 and 17 an other hub element 3 is now used with other axial dimensions. As the distant piece 26 from fig. 16 is taken out the housing 4 is connected with the suspension 25 directly, i. e. not via the distance piece 26. Consequently, the drive shaft 57 extends by the amount x further beyond the housing 4 to the left in fig. 17. To establish the right axial position between the end of the drive shaft 57 and the end of the hub element 3 a fixation element 60' is now used which is a part of a set of fixation elements 60, 60'. The different fixation elements 60, 60' establish different axial mounting surfaces. Consequently, different axial positions between the axial end of the drive shaft 57 and the axial end of the hub element 3 are achieved.

As can be seen in fig. 17, the fixation element 60' has a sleeve like part 61 with axial end sides establishing contact surfaces to be mounted with the axial end of the drive shaft 57 and the hub element 3 respectively. The first end surface 62 is brought into contact with the face side of the drive shaft 57 and fixed with a screw or bolt 64. The second contact surface 63 is brought into contact with the face side of the hub element 3. Consequently, the exact axial distance is obtained after mounting of the fixation element 60' to bring the hub element 3 into the right axial position with respect to the drive shaft 57.

As the hub elements 3 are different for the single tire concept (see fig. 20) and for the dual tire concept (fig. 21) it is necessary to fix the brake caliper 66 in different axial positions relatively to the housing 4. For this the brake caliper 66 is brought into the correct position where it is fixed at the housing 4 e. g. by means of bolts or screws.

As can be seen in fig. 18 a couple of holes 65 are machined into the housing 4 to form means for fixing the brake caliper. Two sets of bores 65 are arranged in an axial distance x which corresponds to the axial distance of the distance piece 26. This situation is depicted in fig. 19. 1. e. the axial pitch x of the holes 65 for the fixation of the brake caliper 66 is equal to the length x of the distance piece 26. As can be seen in fig. 20 a certain axial space y is provided which is at least as long as the axial distance x to make sure that no collision takes place when the distance piece 26 is taken out and the housing 4 slides on the support 67 in the position depicted in fig. 21.

Is should be noted that an alternative design is also possible where the distance piece 26 is positioned at the location where the axial extension y is depicted in fig. 20, i. e. between the support 67 and the bearing 5 and concentrically to the drive shaft 26.

The length and position of the drive shaft 57 is always constant regardless if the single tire concept or the dual tire concept is realized, which have their own respective hub elements 3' and 3". The support 67 can be fixed onto the suspension 25 by. e. g. friction welding or can be pressed in or on the suspension tube, e. g. combined with energy welding. The hub unit, i.e. the wheel hub, can be made from light metal, e.g. from aluminum. Of course, also cast iron can be used.

The mounting and dismounting of the arrangement is significantly facilitated and a changeover from a single tire concept to a dual tire concept can be easily carried out. The brake assembly, i.e. the brake disc can remain at a defined axial position so that no modifications must be done when changing the concept. This makes it easier to realize both concepts with a minimum number of required parts. The brake disc can also float axially in case a fixed brake caliper is applied. The bearing 5 can be pre-mounted before being assembled into the bearing arrangement 1. Thereby, a defined pre-load can be permanently or semi-permanently adjusted. With the suggested concept is becomes possible to carry out maintenance services for the brake disc without disassembly of the whole wheel end bearing arrangement. A further advantage of the design is that a reduced heat transfer takes place from the brake disk to the bearing 5.

Reference Numerals :

1 bearing arrangement

2 hub unit

3 hub element

3' hub element for single tire concept

3" hub element for dual tire concept

4 housing

5 bearing

6 inner ring

7 inner ring

8 outer ring

9 outer ring

10 rolling bodies or elements

11 rolling bodies or elements

12 cylindrically shaped bore

13 locking means

14 recess

15 fastener element

16 bore

17 screw

17' circlip

17" spring element (belleville spring washer)

18 thread

18' ring groove

19 undercut 0 rill 1 guide means 22 axis

23 raceway

24 raceway

25 vehicle suspension (carrier element)

26 distance piece

27 screw

28 screw

29 tire

30 system for surveying the air pressure

31 first air conduit

32 second air conduit

33 end of the air conduit of the inner ring

34 inner of the tire

35 third air conduit

36 end of the air conduit of the inner ring

37 pressure chamber

38 part

39 raceway

40 raceway

41 connection means

42 flange

43 brake disk

44 seal

45 nose

46 cutout

47 reference position

48 fourth air conduit

49 cap

50 connection element 51 flange

52 flange

53 seal

54 seal

55 pressure tube

56 ring part (spacer)

57 drive shaft

58 means to establish a torque drive (spline connection)

59 intermediate part (part adjacent to the inner ring)

60 fixation element

60' fixation element

61 sleeve-like part

62 first contact surface

63 second contact surface

64 bolt/screw

65 means for fixing the brake caliper (bore)

66 brake caliper

67 support

68 flange

69 bore

70 outer circumference

71 intermediate part

72 flange

X axial extension y axial extension

Claims

Claims:

1. Bearing arrangement (1) for a hub unit (2) of a driven or non-driven vehicle wheel end, especially of a truck or trailer, wherein a hub element (3) is supported relatively to a housing (4) by means of a bearing (5) with at least one rotating inner ring (6, 7), at least one stationary outer ring (8, 9) and rolling bodies (10, 11) between them, wherein the wheel hub element (3) is connected with the at least one inner ring (6, 7), wherein the at least one outer ring (8, 9) is connected with the housing (4), wherein at least one tire (29) is mounted on the hub unit (2) and wherein the bearing arrangement (1) is equipped with a seal unit system

(30) for surveying the air pressure in the tire (29), characterized in that an air conduit (31) of the system (30) for surveying the air pressure in the tire (29) is extending axially through the at least one inner ring (6, 7) ofthe bearing (5).

2. Bearing arrangement according to claim 1, characterized in that a second air conduit (32) connects one of the ends (33) of the air conduit (31) of the inner ring (6, 7) with the inner (34) of the tire (29).

3. Bearing arrangement according to claim 2, characterized in that a third air conduit (35) connects the other end (36) of the air conduit (31) of the inner ring (6, 7) with a pressure chamber (37), wherein the third conduit (35) extends radially from the end of the air conduit (31) of the inner ring (6, 7) through the inner ring (6, 7) or a part (38) adjacent to the inner ring (6, 7).

4. Bearing arrangement according to at least one of claims 1 till 3, characterized in that at least one seal unit is arranged at the end of a conduit (31, 32, 35, 48).

5. Bearing arrangement according to at least one of claims 1 till 4, characterized in that the at least one outer ring (8, 9) is arranged in a cylindrically shaped bore (12) of the housing (4) and wherein the at least one outer ring (8, 9) is axially locked by connecting means (13) relatively to the housing (4), wherein the connecting means (13) comprise at least one recess (14) in the outer circumference of the at least one outer ring (8, 9) and/or in the outer circumference of a ring part (56) adjacent to and connected with the at least one outer ring (8, 9) and at least one fastener element (15) which can be inserted and fixed in a bore (16) in the housing (4), so that the end of the fastener element (15) engages into the recess (14) to axially lock the at least one outer ring (8, 9) relatively to the housing (4).

6. Bearing arrangement according to at least one of claims 1 till 5, characterized in that the bearing (5) is pre-loaded.

7. Bearing arrangement according to claim 5 or 6, characterized in that the bore (16) in the housing (4) extends radially through the housing (4).

8. Bearing arrangement according to claim 5 or 6, characterized in that the bore (16) in the housing (4) extends under an angle to the radial direction through the housing (4).

9. Bearing arrangement according to at least one of claims 5 till 8, characterized in that the bore (16) in the housing (4) has a round cross section.

10. Bearing arrangement according to at least one of claims 5 till 8, characterized in that the bore (16) in the housing (4) has an out of round cross section.

11. Bearing arrangement according to at least one of claims 5 till 10, characterized in that the recess (14) in the outer circumference of the at least one outer ring (8, 9) or in the outer circumference of the ring part (56) adjacent to and connected with the at least one outer ring (8, 9) is a groove, running around the whole circumference of the at least one outer ring (8, 9) or ring part (56).

12. Bearing arrangement according to at least one of claims 5 till 11, characterized in that the fastener element (15) is fixed in its final position by means of a mechanical locking device (17, 17').

13. Bearing arrangement according to claim 12, characterized in that the mechanical locking device is a screw (17).

14. Bearing arrangement according to claim 13, characterized in that the bore (16) in the housing (4) is equipped with a thread (18) for the screw

(17).

15. Bearing arrangement according to claim 12, characterized in that the mechanical locking device is a circlip (17').

16. Bearing arrangement according to claim 15, characterized in that the bore (16) in the housing (4) is equipped with a groove (18') for the circlip (17').

17. Bearing arrangement according to claim 15 or 16, characterized in that a spring element (17") is located between the fastener element (15) and the circlip (17').

18. Bearing arrangement according to claim 17, characterized in that the spring element (17") is abelleville spring washer.

19. Bearing arrangement according to claim 17, characterized in that the spring element (17") is a rubber or elastomer ring.

20. Bearing arrangement according to at least one of claims 5 till 19, characterized in that the at least one recess (14) in the outer circumference of the at least one outer ring (8, 9) and/or in the outer circumference of the ring part (56) adjacent to and connected with the at least one outer ring (8, 9) has a shape defining an undercut (19) in axial direction of the at least one outer (8, 9).

21. Bearing arrangement according to claim 20, characterized in that the recess (14) is a groove with at least two adjacent rills (20) which run around the whole circumference of the at least one outer ring (8, 9) and/or the whole circumference of the ring part (56) adjacent to and connected with the at least one outer ring (8, 9) and that the fastener element (15) has a corresponding shape at its end contacting the rills (20).

22. Bearing arrangement according to claim 21, characterized in that the at least one outer ring (8, 9) and/or the ring part (56) adjacent to and connected with the at least one outer ring (8, 9) comprises a plurality of adjacent rills (20).

23. Bearing arrangement according to at least one of claims 20 till 22, characterized in that the fastener element (15) is equipped with guide means (21) which prevent a rotational movement of the fastener element (15) around the axis (22) of the bore (16) in the housing (4).

24. Bearing arrangement according to at least one of claims 1 till 23, characterized in that the bearing (5) is a two row bearing, e.g. a roller bearing, a ball bearing or a combination of these.

25. Bearing arrangement according to claim 24, characterized in that the connecting means (13) are located between the raceways (23, 24) for the rolling bodies (10, 11) preferably in at least one minimum loaded or non- loaded zone.

26. Bearing arrangement according to claim 24 or 25, characterized in that the ring part (56) is located as a spacer ring between two outer rings (8, 9) ofthe bearing (5).

27. Bearing arrangement according to claim 26, characterized in that only the ring part (56) comprises the at least one recess (14).

28. Bearing arrangement according to claim 24 or 25, characterized in that the outer ring (8, 9) is made as a one piece which comprises two raceways (23, 24) for the rolling bodies (10, 11).

29. Bearing arrangement according to claim 24 or 25, characterized in that the bearing (5) comprises two outer rings (8, 9), which are axially connected by the fastener element (15) in the mounted state.

30. Bearing arrangement according to at least one of claims 1 till 29, characterized in that the hub unit (2) and/or the hub element (3) is made of cast iron.

31. Bearing arrangement according to at least one of claims 1 till 29, characterized in that the hub unit (2) and/or the hub element (3) is made of light metal, especially of aluminium.

32. Bearing arrangement according to at least one of claims 1 till 31, characterized in that it is equipped with at least one seal unit.

33. Bearing arrangement according to at least one of claims 1 till 32, characterized in that it is equipped with at least one sensor device to monitor and/or control at least one wheel end function.

34. Bearing arrangement according to claim 33, characterized in that the sensor device is designed to monitor and/or control the rotational speed of the hub unit or adjacent parts of it.

35. Bearing arrangement according to claim 33, characterized in that the sensor device is designed to monitor and/or control the vibration of the hub unit or adjacent parts of it.

36. Bearing arrangement according to claim 33, characterized in that the sensor device is designed to monitor and/or control the temperature of the hub unit or adjacent parts of it.

37. Bearing arrangement according to claim 33, characterized in that the sensor device is designed to monitor and/or control the load of the hub unit or adjacent parts of it.

38. Bearing arrangement according to claim 37, characterized in that the sensor for monitoring the load is connected with the brake system and/or control system of the vehicle for controlling the dynamic behavior of the vehicle.

39. Bearing arrangement according to at least one of claims 1 till 38, characterized in that the housing (4) is connected with a suspension (25) and that a distance piece (26) of defined axial extension (x) is detachably arranged between the housing (4) and the suspension (25).

40. Bearing arrangement according to claim 39, characterized in that the connection between the distance piece (26) and the housing (4) as well as the connection between the distance piece (26) and the suspension

(25) is realized by means of screws or bolts (27, 28).

41. Bearing arrangement according to at least one of claims 1 till 40, characterized in that the housing (4) is connected with a suspension (25) and that a drive shaft (57) extends through the suspension (25) which is equipped with drive means (58) to establish a torque drive between one end of the drive shaft (57) and the hub element (3), wherein the suspension (25) and the housing (4) are equipped with means (67, 69, 27) which allow a relative axial movement between the suspension (25) and the housing (4) and a locking of the housing (4) relatively to the suspension (25) in a defined axial position.

42. Bearing arrangement according to claim 41, characterized in that the means (67, 69) comprise a support (67) with a cylindrical outer circumference (70) and a bore (69) in the housing (4).

43. Bearing arrangement according to claim 42, characterized by a press fit, a transition fit or a clearance fit between the outer circumference (70) of the support (67) and the bore (69) in the housing (4).

44. Bearing arrangement according to at least one of claims 41 till 43, characterized in that the housing (4) and the support (67) form an axial sliding arrangement.

45. Bearing arrangement according to at least one of claims 41 till 44, characterized in that a fixation element (60, 60') is detachably arranged at one end of the drive shaft (57) for the axial fixation of the drive shaft (57) relatively to the hub element (3), so that a defined axial position exists between the drive shaft (57) and the hub element (3).

46. Bearing arrangement according to at least one of claims 41 till 45, characterized in that the housing (4) is centered and bolted relatively to the suspension (25) by the means (67, 69, 27).

47. Bearing arrangement according to at least one of claims 41 till 46, characterized in that a fixation element (60, 60') is detachably arranged at one end of the drive shaft (57) for the axial fixation of the drive shaft (57) relatively to the hub element (3), so that a defined axial position exists between the drive shaft (57) and the hub element (3).

48. Bearing arrangement according to claim 47, characterized in that the fixation element (60, 60') is a part of a set of fixation elements (60, 60') which establish different axial relations between the axial end of the drive shaft (57) and the axial end of the hub element (3).

49. Bearing arrangement according to claim 48, characterized in that at least one of the fixation elements (60, 60') of the set of fixation elements (60') comprise a sleeve-like part (61) with a first contact surface (62) for one axial end of the drive shaft (57) and a second contact surface (63) for one axial end of the hub element (3).

50. Bearing arrangement according to at least one of claims 47 till 49, characterized in that the fixation element (60, 60') comprises at least one bolt or screw (64) which connects the axial end of the drive shaft (57) with the hub element (3).

51. Bearing arrangement according to at least one of claims 41 till 50, characterized in that the housing (4) has at least two means (65) for fixing a brake caliper (66) on the housing (4), wherein the at least two means (65) are located in a defined axial distance (x) at the housing (4).

52. Bearing arrangement according to claim 51, characterized in that the means (65) for fixing the brake caliper (66) comprises at least one bore or recess extending in radial direction through or into the housing (4).

53. Bearing arrangement according to at least one of claims 41 till 52, characterized in that the means (58) to establish a torque drive between one end of the drive shaft (57) and the hub element (3) are a spline connection.

54. Bearing arrangement according to at least one of claims 41 till 53, characterized in that a distance piece (26) of defined axial extension (x) is detachably arranged between the housing (4) and the suspension (25).

55. Bearing arrangement according to claim 51 and 54, characterized in that the axial distance (x) between the at least two means (65) for fixing the brake caliper (66) on the housing (4) and the axial extension (x) of the distance piece (26) are identical.

56. Bearing arrangement according to claim 54 or 55, characterized in that the distance piece (26) is ring shaped and arranged on the cylindrical outer circumference (70) of the support (67).

57. Bearing arrangement according to at least one of claims 54 till 56, characterized in that the fixation of the distance piece (26) with the housing (4) as well as the fixation of the distance piece (26) with the suspension (25) is realized by means of screws or bolts (27).

58. Bearing arrangement according to at least one of claims 54 till 57, characterized in that the distance piece (26) is made from a metallic or non-metallic material, preferably from steel or cast aluminium.

59. Bearing arrangement according to at least one of claims 54 till 58, characterized in that the distance piece (26) has an axial extending slot.

60. Bearing arrangement according to at least one of claims 41 till 59, characterized in that the fixation of the housing (4) with the suspension (25) is done by means of screws or bolts (27) in axial and radial direction.

61. Bearing arrangement according to at least one of claims 41 till 60, characterized in that means (67, 69, 27) for allowing a relative axial movement between the suspension (25) and the housing (4) and preferably adjacent parts of them are sealed off against the environment.

62. Bearing arrangement according to claim 61, characterized in that the sealing means comprise a shrink foil or a silicon paste or a combination of these.

63. Bearing arrangement according to at least one of claims 42 till 62, characterized in that the support (67) is fixed with the suspension (25) by welding, especially by friction welding.