KR20080018610A - Brake disk wheel bearing assembly for vehicle - Google Patents

Abstract

A brake disk-wheel bearing assembly for a vehicle is provided to prevent a judder from occurring by decreasing a run-out of a brake disk. A brake disk-wheel bearing assembly comprises a plurality of first rolling elements(103) aligned on a raceway. A plurality of second rolling elements(104) are aligned on the raceway toward inner side of a vehicle relative to the first rolling elements. An outer ring(106) provides an outer raceway of the first and second rolling elements. An inner ring(107) provides an inner raceway of the first rolling element. An inner ring shaft(105) provides an inner raceway of the second rolling element. The inner ring shaft includes a shoulder part(105a), a male screw part(105e) and an inner ring coupling part(105d). A brake disk includes a central bore. The male screw part is secured with the central bore.

Description

Brake Disc Wheel Bearing Assembly for Vehicles {BRAKE DISK WHEEL BEARING ASSEMBLY FOR VEHICLE}

1 is a cross-sectional view of a disc brake-wheel bearing assembly according to the prior art.

2 is a cross-sectional view of a disc brake-wheel bearing assembly according to the prior art.

3 is a cross-sectional view of a disc brake-wheel bearing assembly for a drive wheel according to the prior art.

4 is a cross-sectional view of a disc brake-wheel bearing assembly for a driven wheel according to the prior art.

Figure 5 is a cross-sectional view showing one embodiment of a wheel bearing assembly according to the present invention.

6 is an exploded view of a brake disc wheel bearing assembly according to the present invention.

7 is an assembled view of a brake disc-wheel bearing assembly according to the present invention coupled to a drive shaft and a knuckle.

Figure 8 is a partial cross-sectional view of one embodiment of a wheel bearing assembly in accordance with the present invention.

9 is a sectional view showing another embodiment of the wheel bearing assembly according to the present invention;

FIG. 10 is a sectional view taken along the line A-A of FIG.

11 is a perspective view and a partially enlarged view of the inner ring shaft according to the present invention;

Fig. 12 is a plan view showing a spline on which guides are viewed in the direction of arrow B in Fig. 8;

Figure 13 is an exploded view of a brake disc wheel bearing assembly according to the present invention.

FIG. 14 is a sectional view along line C-C in FIG. 13; FIG.

Fig. 15 is an enlarged view of a state of assembly and a caulking portion of a brake disc-wheel bearing assembly according to the present invention coupled to a drive shaft and a knuckle;

<Explanation of symbols for the main parts of the drawings>

100, 200: brake disc-wheel bearing assembly

101, 201: wheel bearing assembly

103, 203: first rolling element

104, 204: second rolling element

105, 205: inner ring shaft

106, 206: outer ring

107, 207: inner ring

112, 212: knuckles

118, 218: hub brake disc

140, 240: drive shaft

150, 250: wheel nuts

152: split pin

210: caulking part

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake disc-wheel bearing assembly of a vehicle, and more particularly to a brake disc-wheel bearing assembly having a hub-type brake disc in which a hub is integrally formed and an inner ring shaft without a hub flange.

The braking device of a vehicle having a brake disc is configured in such a manner that the brake disc that rotates together with the wheels is braked by hydraulically pressing the brake pads on both sides thereof. The brake device having a brake disc is coupled to a hub flange and rotates together and is made of a special cast iron brake disc, a caliper made of special cast iron in a saddle shape, and two brakes coupled to the left and right sides of the caliper. A cylinder, a piston, and a pad attached to the piston generate a braking force by friction with the brake disc. The brake disc of the braking device is coupled to the wheel bearing assembly, which is coupled between the knuckle portion of the vehicle body and the drive shaft. The wheel bearing assembly serves to support the load of the vehicle and to smooth the rotation of the wheel.

As a conventional brake disc wheel bearing assembly, as shown in Fig. 1, the wheel bearing 1 is a separate part from the hub flange 2. In addition, there is a brake disc-wheel bearing assembly in which the outer ring 3 and the hub flange 4 are integrally formed as shown in FIG. 2 to improve this to reduce the number of related parts and to facilitate assembly and disassembly. However, such a wheel bearing assembly is that the inner ring (5) is fixed and the outer ring (3) is rotated can be applied only to the driven wheel, there is a disadvantage that can not be applied to the drive wheel.

As another brake disc wheel bearing assembly, as shown in Figs. 3 and 4, the inner ring and the hub flange are integrally formed. Figure 3 shows a brake disc-wheel bearing assembly for a drive wheel, and Figure 4 shows a brake disc-wheel bearing assembly for a driven wheel. This type of brake disc-wheel bearing assembly comprises small inner rings 6, 6 'and inner ring hubs 7, 7' divided into two parts as elements corresponding to a conventional inner ring. The inner ring hubs 7, 7 ′ are formed with hub flanges 9, 9 ′ on which outer wheels and brake discs 8, 8 ′ are coupled.

Referring to Fig. 3, the brake disc-wheel bearing assembly 10 for driving wheels includes an inner ring hub 7 integrally equipped with a hub flange 9, a plurality of first rolling elements 13, and a plurality of second rolling elements. 14, the outer ring 16 and the small inner ring 6 are included. On the radially outer surface of the inner ring hub 7, the first and second rolling elements 13 and 14 and the outer ring 16 are engaged, and then the small inner ring 6 is press-fitted. The inner ring hub 7 and the small inner ring 6 form inner raceways of the first rolling element 13 and the second rolling element 14, respectively. A brake disc 8 and a wheel (not shown) are coupled to the hub flange 9 located at the vehicle outer end of the inner ring hub 7 by a hub bolt 18. The outer ring 16 is provided with a flange 19 having a bolt through hole for fastening to the knuckle 12 of the vehicle with the bolt 20.

Since the driving force of the drive shaft is not transmitted to the brake disc-wheel bearing assembly 10 'for the driven wheel shown in Fig. 4, the bore for inserting the drive shaft is not formed in the inner ring hub 7', The flange 22 'is formed in the inner end of the inner ring hub 7' so that the inner ring 6 'does not escape.

The brake disc wheel bearing assembly shown in Figs. 3 and 4 has a brake disc (8, 8 ') superimposed on the hub flange (9, 9') and is coupled to the hub bolt (18, 18 ') to a nut (shown). And the surfaces of the brake discs 8 and 8 'which are in contact with each other when the brake discs 8 and 8' are assembled to the hub flanges 9 and 9 ', the manufacturing tolerances of the hub flanges 9 and 9' The increase in the assembly tolerance due to the accumulation of manufacturing tolerances of the brake discs 8 and 8 'has a problem that it is difficult to limit the run-out of the brake discs 8 and 8' to be small and increase the rigidity. Therefore, in the conventional brake disc, the runout upper limit is regulated to, for example, a level of 50 mu m. Brake discs having this level of runout tend to easily cause judder due to poor axial runout when braking, and it is difficult to fundamentally resolve consumer complaints. In addition, since the brake discs 8 and 8 'are bolted to the hub flanges 9 and 9', there is also a problem in that the overall weight is increased than when these parts are integrated.

In addition, the brake disc-wheel bearing assembly is difficult to process precisely because the surface where the brake disc and the hub flange are coupled to form a concave orthogonal surface. In addition, machining of tab holes for assembling the brake disc is also required. Accordingly, the brake disc-wheel bearing assembly has a problem in that the machining process is complicated, the machining time is high, and the cost is high.

Meanwhile, in order for the brake disc wheel bearing assembly to operate at an optimal life, a predetermined preload is applied to the bearing rolling elements, and the conventional brake disc wheel bearing assemblies are mostly assembled at the final stage of the module or vehicle manufacturer. The preload changes due to the coupling with the associated components in the sluice, affecting the performance and life of the bearing.

SUMMARY OF THE INVENTION The present invention solves these problems with prior art brake disc-wheel bearing assemblies, and provides a brake disc wheel bearing assembly structure in which the preload of a predetermined bearing is not affected or hardly affected in the final assembly process of the vehicle. It aims to provide.

The present invention also aims to provide a wheel bearing assembly in which the engaging portion of the brake disc and the wheel bearing assembly can be easily machined.

It is also an object of the present invention to provide a brake disc-wheel bearing assembly which has a small run out of the brake disc and is free from inconvenience due to judging during operation.

It is an object of the present invention to provide a brake disc-wheel bearing assembly in which the rigidity of the brake disc is increased and the overall weight is reduced.

The brake disc wheel bearing assembly according to an embodiment of the present invention includes a plurality of first rolling elements arranged in track and a plurality of second rolling elements arranged in track in an inward direction of the vehicle than the first rolling elements. An outer ring providing an outer raceway surface of the first rolling element and an outer raceway surface of the second rolling element on an inner circumferential surface, an inner ring providing an inner raceway surface of the first rolling element on an outer circumferential surface, and a second on an outer circumferential surface; An inner raceway shaft providing an inner raceway surface of the rolling element, and a brake disc, the inner raceway shaft having a shoulder positioned at an inner end of the vehicle, a male threaded portion located at the other end, and between the shoulder portion and the male screwed portion; And an inner ring coupling portion in which the inner ring is press fit and the first and second rolling elements are angular contact with each of the outer raceway surface and the inner raceway, Disc is characterized in that it is provided, and is screwed into the male screw portion said central bore given a predetermined preload to the first and second rolling members the central bore the female thread portion is formed.

According to another embodiment of the present invention, a brake disc-wheel bearing assembly includes a plurality of first rolling elements arranged on track and a plurality of second rolling elements arranged on track in an inward direction of the vehicle than the first rolling elements. An outer ring providing an outer raceway surface of the first rolling element and an outer raceway surface of the second rolling element on an inner circumferential surface, an inner ring providing an inner raceway surface of the first rolling element on an outer circumferential surface, and a second on an outer circumferential surface; An inner wheel shaft providing an inner raceway surface of the rolling element, and a brake disc, the inner wheel shaft having a shoulder portion, an inner ring coupling portion in which the inner ring is forcibly fitted, a spline portion, and a caulking in turn from an inner end portion of the vehicle; And first and second rolling elements in angular contact with each of the outer raceway surface and the inner raceway surface, and the brake disc is coupled to the male spline portion of the inner ring shaft. Having a central bore which is formed, and wherein the brake disk is characterized in that by the caulking portion is pressed and fixed between the inner ring and the crimping portion.

5 shows one embodiment of a wheel bearing assembly 101 in accordance with the present invention. The wheel bearing assembly 101 includes first and second rolling elements 103 and 104, an outer ring 106, an inner ring 107, and an inner ring shaft 105. The outer ring 106 has an outer raceway surface of the first rolling element 103 and an outer raceway surface of the second rolling element 104 on its inner circumferential surface, and a screw through for mounting to the vehicle body on the outer circumferential surface of the outer ring 106. The flange with which the hole 106a is provided is formed. The inner ring 107 is disposed outside the wheel with respect to the first rolling element 103 and has an inner raceway surface of the first rolling element 103.

The inner ring shaft 105 is divided into a shoulder portion 105a, a raceway portion 105b, an inner ring coupling portion 105d, and a male screw portion 105e. The shoulder portion 105a and the raceway portion 105b formed at the vehicle inner side end portion of the inner ring shaft 105 form the inner raceway surface of the second rolling element 104. The inner ring 107 is forcibly fitted to the inner ring engaging portion 105d. The inner ring 107 is forcibly fitted in the axial direction from the outside of the vehicle (ie, the wheel side). Therefore, as compared with the prior art of the shape where the inner ring is disposed inside the vehicle with respect to the rolling element, the assembly of the wheel bearings is easy and the bearing related parts can be easily replaced. The jaw 105c is formed between the inner ring engaging portion 105d and the track portion 105b. The inner ring 107 is inserted until one end thereof abuts against the jaw 105c to form an interference fit.

The first and second rolling elements 103 and 104 are in angular contact with each of the outer raceway surface and the inner raceway surface. Here, the angular contact means that the rolling element contacts the outer ring and inner ring of the bearing such that the line connecting the contact point of the rolling element (for example, the bearing ball) with the inner ring and the contact point with the rolling element with the outer ring forms a predetermined angle with respect to the axial direction of the rotating shaft. It is a state of being. Since the rolling element of this embodiment makes angular contact, it can support both an axial load and a radial load. Through such a combination, the wheel bearing assembly forms a submodule consisting of the first and second rolling elements, the outer ring, the inner ring, and the inner ring shaft.

A male screw portion 105e is formed on the outer circumferential surface of the other end of the inner ring shaft. A hub (not shown) component for coupling the brake disc may be coupled to the male screw portion 105e, and preferably, a hub type brake disc 118 (see FIG. 6) formed integrally with the hub may be coupled. . A female thread is formed on the inner circumferential surface of the hub component or the hub brake disc coupled to the male thread portion.

6 and 7 illustrate a coupling relationship between the brake disc-wheel bearing assembly 100 and the vehicle knuckle 112 and the drive shaft 140 of the present invention. The hub brake disc 118 has a center bore with a female threaded portion. The male thread portion 105e of the inner ring shaft 105 is screwed into the center bore of the hub brake disc 118. By doing so, the wheel bearing assembly 101 and the hub brake disc 118 are integrally combined to form a brake disc-wheel bearing assembly 100 which is one module. In particular, the module has an inner ring that is forcibly fitted to the inner ring engaging portion 105d of the inner ring shaft 105, and the hub brake disc 118 is screwed to the male thread portion 105e, thereby providing The preset preload is applied to the second rolling element. The rolling elements of the wheel bearing are driven in a track formed by the outer ring and the inner ring (or the inner ring shaft), which are operated in a state of elastic compression at a constant pressure. This pressure is called preload, which has a very important influence on the performance and life of the bearing.

Since the hub brake disc 118 is coupled to the inner ring shaft 105 by screws, the preload of the wheel bearing assembly 101 can be precisely adjusted. In addition, in the case where excessive preload is applied, it is easy to make adjustment to reduce the preload again.

In the brake disc wheel bearing assembly 100, since the hub brake disc 118 is screwed to the inner ring shaft and constitutes a submodule, the brake disc wheel bearing assembly 100 is pre-assigned to the bearing in the manufacturing process of the brake disc wheel bearing assembly 100. Adjusted preload is hardly affected when assembled with other parts of the vehicle. In addition, even if the brake disc-wheel bearing assembly 100 is removed from the drive shaft during the maintenance process, there is no fear that the bearing balls may detach.

The brake disc-wheel bearing assembly 100 thus having a predetermined adjusted bearing preload is fixed to the vehicle by the outer ring 106 being coupled to the knuckle 112 of the vehicle by bolts 120. On the other hand, the drive shaft 140 is inserted into the bore formed in the center of the inner ring shaft 105, the inner ring shaft 105 and the drive shaft 140 is splined to each other. The wheel nut 150 is fastened to the male threaded portion formed at the end of the drive shaft 140, and the split pin 152 is inserted to penetrate the groove formed in the wheel nut 150 and the hole formed at the end of the drive shaft 140. The end of 152 is bent to secure the wheel nut 150. As a result, the driving force of the drive shaft 140 is transmitted to the hub brake disc 118 through the inner ring shaft 105. When the hub-type brake disc 118 is screwed to the inner ring shaft 105, a predetermined preload is applied to the bearing. Therefore, in the process of fastening the wheel nut 150, the drive shaft 140 and the preload of the bearing are not considered. The wheel nut 150 may be fastened to the drive shaft 140 by a torque for fastening the motor.

On the other hand, during braking, the hub-type brake disc 118 may apply a compressive force to the inner ring 107 while trying to proceed in the screw locking direction. Various known fastening means, such as keys or pins, may be used to prevent relative rotation of the hub brake disc 118 relative to the inner ring shaft 105 of the threaded movement along the thread. In addition, as shown in Fig. 8, when the inner ring thickness a is 0.3 times the rolling element diameter and the inner wheel minimum length b is 2 mm to 4 mm, the rigidity of the inner ring is increased. Even if the force is applied in the direction of locking, the rigidity of the inner ring subjected to the compressive force by the hub brake disk is very large, so that the amount of change in the axial direction of the inner ring hardly occurs, whereby the inner ring stops the disk from moving inward of the vehicle. (stopper) Play enough.

Referring to FIG. 7, the hub brake disc 118 includes a friction material contact surface 132, a wheel contact surface 134, a hub bolt insertion hole 138, and a center bore 139 from the radially outer side. The central bore 139 has a female screw formed on an inner circumferential surface thereof. A protrusion 136 is formed between the hub bolt insertion hole 138 and the central bore 139. The protrusion 136 provides an effect of preventing foreign matter from entering the raceway surface of the rolling element. Foreign matter and moisture from the outside of the vehicle will be blocked first before it reaches the seal of the bearing, significantly reducing the likelihood that foreign matter and moisture will penetrate into the seal. Also, The projection 136 also serves to enable post-assembly processing in the machining process of the friction material contact surface 132 and the wheel contact surface 134 of the brake disc-wheel bearing assembly 100 to be described later.

Since the inner ring shaft 105 is directly coupled to the hub brake disc 118 by screwing, the machining process of the assembly surface between the hub flange and the brake disc is omitted, and there is no tolerance accumulation due to such assembly. As a result, the runout of the brake disc can be restricted to a small size.

9 shows another embodiment of a wheel bearing assembly 201 in accordance with the present invention. The inner ring shaft 205 has the shoulder 205a, the track 205b, the jaw 205c, the inner ring coupling 205d, the spline 205f, and caulking on the outer circumferential surface of the vehicle 205a, the track 205b, and the jaw 205c. ) Forming portion 205g. As shown in Fig. 10, the inner ring shaft 205 has a male spline portion 205f on a part of its outer circumferential surface and an arm spline portion on its inner circumferential surface. The male spline portion 205f of the inner ring shaft 205 is for coupling with the hub brake disc 218 (see FIG. 13), and the female spline portion of the inner ring shaft 205 is connected to the drive shaft 240 (see FIG. 13). For the combination of

11 is a perspective view of the inner ring shaft 205. One end of each of the male spline teeth in the male spline portion 205f of the inner ring shaft 205 may be provided with a guide 205f 'for guiding the insertion of the hub brake disc into the central bore. FIG. 12 shows the shape of the guide as seen in the direction of arrow B of FIG. The male spline portion 205f has a smaller width in the guide 205f '. It is also possible to make the diameter of the male spline smaller in the guide than that of other portions of the male spline portion. The guide serves to guide the engagement position at its leading end when the disc engagement portion engages with the hub brake disc to facilitate assembly. Fig. 12 shows a step-shaped guide viewed from the side. In addition, the guide may be implemented in various forms such as a taper.

13 shows a coupling relationship between the wheel bearing assembly 201, the hub brake disc 218, the drive shaft 240, and the knuckle 212. The male spline portion of the wheel bearing assembly 201 is inserted into the central bore of the hub brake disc 218. As shown in FIG. 14, an arm spline is formed in the center bore of the hub brake disc 218. As shown in FIG. The spline coupling method can support a larger driving force because of the large contact area of the coupling portion.

Figure 15 illustrates a brake disc-wheel bearing assembly 200 in accordance with the present invention. As shown in Fig. 15, after the hub brake disc 218 is fitted to the disc engaging portion of the inner ring shaft, the caulking forming portion 205g (Fig. 9) is cocked to fix the hub brake disc 218. Preload. A flat portion 211 is formed at the outermost side of the caulking portion 210. The flat portion 211 is a surface in contact with the wheel nut 250, the wheel nut 250 is in surface contact with the flat portion 211 of the caulking portion to accurately adjust the tightening force of the wheel nut 250 drive shaft 240 And to the brake disc-wheel bearing assembly 200.

The caulking unit 210 serves to set and maintain a predetermined preload on the rolling element of the brake disc wheel bearing assembly 200 before the brake disc wheel bearing assembly 200 is assembled to the drive shaft and the knuckle. module In the assembling process, the brake disc-wheel bearing assembly 200 is coupled to the drive shaft and the wheel nut 250 is fastened to the male threaded portion of the drive shaft 240. At this time, the fastening force of the tightened wheel nut 250 is set to the rolling element. Does not affect the preload, only the wheel nut 250 serves to couple the drive shaft 240 and the brake disc-wheel bearing assembly 200.

[Method of processing wheel bearing assembly]

The hub-type brake discs 118 and 218 are ground or coupled to the friction material contact surfaces of the hub-type brake discs with the wheel bearing assemblies 101 and 201 coupled thereto.

The machining method of the friction material contact surface of the brake disc wheel bearing assembly 100, 200 of the present invention is as follows. With the hub brake discs 118 and 218 and the wheel bearing assemblies 101 and 201 assembled, chucking the outer circumferential surfaces of the outer rings 106 and 206 relative to the flange faces of the outer rings of the wheel bearing assemblies 101 and 201 (see FIG. chucking). Then, on one side, a corresponding axial pressure is applied to the shoulders of the inner ring shafts 105 and 205 at the shoulder side of the inner ring shafts 105 and 205, and on the other side, the vehicle is fixed to the central side of the hub brake disks 118 and 218. Apply the appropriate axial pressure during assembly. A grinding or cutting tool is placed on both sides of the hub brake discs 118, 218. Both surfaces of the friction material contact surfaces of the hub brake discs 118 and 218 are simultaneously processed while rotating the spindle of the fixed shaft. Alternatively, both surfaces of the friction material contact surfaces of the hub-type brake discs 118 and 218 may be simultaneously processed by inserting the wheel bearing assemblies 101 and 201 into the drive shaft, tightening the nuts, and rotating the drive shaft. Since the brake disc-wheel bearing assembly 100 and 200 of the present invention has not only a seal formed on the wheel bearing, but also protrusions 136 and 236 are formed on the hub brake discs 118 and 218, the hub type Even after machining the friction material contact surface after assembling the brake discs 118 and 218 and the wheel bearing assemblies 101 and 201, foreign substances such as metal chips generated during machining do not enter the bearing gap.

As such, the friction material contact surfaces of the hub brake discs 118 and 218 are ground first by processing the friction material contact surfaces while the hub brake disks 118 and 218 are firmly assembled to the wheel bearing assemblies 101 and 201. Since the problem that the runout is changed due to the clamping force during assembly when the assembly is performed on the wheel bearing assemblies 101 and 201 after the runout is fundamentally prevented, the runout can be managed very precisely. In addition, the brake disc-wheel bearing assemblies 100 and 200 of the present invention do not need to bolt the hub brake disc to the hub flange before machining the friction material contact surface, so that the friction material contact surface can be processed more easily than before.

[Runout measurement test]

According to the present invention, the brake disk-wheel bearing assembly 100 which polishes the friction material contact surfaces of the hub brake disks 118 and 218 while the wheel bearing assemblies 101 and 201 and the hub brake disks 118 and 218 are coupled to each other. Runout was measured. To this end, the brake disc-wheel bearing assemblies 100 and 200 are seated and fixed in the runout measuring jig, and the wheel nuts are tightened to the drive shaft with a torque of 20 to 26 kgf.m (same as the mounting torque of the actual vehicle). . The gauge was placed on the friction material contact surfaces of the hub brake discs 118 and 218, and then the amount of change of the gauge was measured while the hub brake discs 118 and 218 were rotated. As a result of the measurement, runout was measured to be less than 20 mu m.

 Although embodiments of the wheel bearing assembly of the present invention have been described so far applied to a drive wheel, the wheel bearing assembly of the present invention is also applicable to a driven wheel.

The above examples should not be construed as limiting the scope of the invention. Those skilled in the art will appreciate that various modifications may be made from the above embodiments without departing substantially from the scope of the present invention. Accordingly, all content included in the above description should be interpreted as illustrative, and not as limiting the scope of the present invention.

One embodiment of the brake disc-wheel bearing assembly according to the present invention provides a brake disc-wheel bearing assembly in which a hub-type brake disc is screwed onto an inner ring shaft, thereby preloading a predetermined preload in an optimal state for the performance and life of the rolling element. It can be given to a bearing precisely. The preload imparted in this way can be kept unchanged in the final assembly process of the vehicle. In addition, by grinding the disk surface while the brake disk is firmly fixed to the wheel bearing assembly, it is possible to reduce runout of the brake disk and to eliminate inconvenience caused by judging during driving. Further, by providing a hub integrated brake disc, the rigidity of the brake disc can be increased and the weight can be reduced.

In another embodiment of the brake disc wheel bearing assembly according to the present invention, by providing a brake disc wheel bearing assembly in which the hub type brake disc spline-coupled to the inner ring shaft is pressed and fixed with a caulking unit, the brake disc wheel bearing assembly is optimal for the performance and life of the rolling element. Preload pre-set in the state can be precisely applied to the bearing, and the preload thus applied can be kept unchanged in the final assembly process of the vehicle.

Claims (5)

A plurality of first rolling elements arranged in a track, a plurality of second rolling elements arranged in a track in an inward direction of the vehicle than the first rolling element, an outer raceway surface of the first rolling element on an inner circumferential surface, and An outer ring providing an outer raceway surface of the second rolling element, an inner ring providing an inner raceway surface of the first rolling element on its outer circumferential surface, an inner raceway shaft providing an inner raceway surface of the second rolling element on its outer circumferential surface, and a brake disc Including; The inner ring shaft includes a shoulder portion positioned at the vehicle inner side end portion, a male screw portion positioned at the other end portion, and an inner ring coupling portion disposed between the shoulder portion and the male screw portion and configured to forcibly fit the inner ring. The two rolling elements are in angular contact with each of the outer raceway surface and the inner raceway surface, and the brake disc has a central bore with a female threaded portion, and the male threaded portion is screwed into the central bore so that the first and second rolling elements Brake disc wheel bearing assembly, characterized in that the predetermined preload is applied to. 2. The brake disc-wheel bearing assembly of claim 1, wherein the inner wheel shaft further comprises means for preventing relative rotation of the brake disk with respect to the inner wheel shaft. A plurality of first rolling elements arranged in a track, a plurality of second rolling elements arranged in a track in an inward direction of the vehicle than the first rolling element, an outer raceway surface of the first rolling element on an inner circumferential surface, and An outer ring providing an outer raceway surface of the second rolling element, an inner ring providing an inner raceway surface of the first rolling element on its outer circumferential surface, an inner raceway shaft providing an inner raceway surface of the second rolling element on its outer circumferential surface, and a brake disc Including; The inner wheel shaft includes a shoulder portion, an inner ring coupling portion in which the inner ring is forcibly fitted, a spline portion, and a caulking portion, in order from the inner side end portion of the vehicle, and the first and second rolling elements each have an outer raceway surface, Angular contact with the inner raceway surface, the brake disc has a central bore with an arm spline coupled with the male spline portion of the inner ring shaft, and the brake disc is pressed between the inner ring and the caulking portion by the caulking portion. And fixed to the brake disc wheel assembly. 4. The brake disc-wheel bearing assembly according to claim 3, wherein a guide for guiding insertion of the brake disc into the center bore is provided on an outer side of the vehicle of the male spline portion. The brake disc-wheel bearing assembly according to any one of claims 1 to 4, wherein the brake disc has a protrusion protruding to surround the outer ring on a surface opposite the outer ring.

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