JP2003002003A - Wheel bearing unit - Google Patents

Abstract

(57) [Problem] To provide a low-cost structure capable of suppressing vibration of a braking rotary body fixed to a hub 8a and preventing judder during braking. SOLUTION: At plural positions in the circumferential direction of a mounting flange 13a provided on the outer peripheral surface of a hub 8a, mounting holes 14 are formed, which penetrate the mounting flange 13 in the axial direction. The mounting flange 13a for fixing the rotating body for braking
An annular projection 28 is formed at a radially intermediate portion on one side of the mounting flange 13a so as to protrude in the axial direction over the entire circumference of the mounting flange 13a. The one side surface of the annular projection 28 in the axial direction is
A plane perpendicular to the rotation center of a. One end of each mounting hole 14 in the axial direction is opened on one axial side surface of the annular projection 28.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a wheel bearing unit for supporting a wheel of an automobile and a rotating body for braking such as a rotor or a drum. 2. Description of the Related Art A wheel 1 constituting a wheel of an automobile and a rotor 2 constituting a disc brake which is a braking device.
Is rotatably supported by a knuckle 3 constituting a suspension device, for example, by a structure as shown in FIG. That is, the outer ring 6, which is a stationary wheel that does not rotate during use and forms a bearing unit for a wheel 5, is fixed to the circular support hole 4 formed in the knuckle 3 by a plurality of bolts 7. On the other hand, the hub 8 constituting the wheel bearing unit 5
The wheel 1 and the rotor 2 are connected to a plurality of studs 9.
And the nut 10 for connection and fixation. On the inner peripheral surface of the outer ring 6 which is a stationary side peripheral surface, a double row outer ring raceway 11 which is a stationary side raceway is provided.
a and 11b, and a coupling flange 12 on the outer peripheral surface. The outer ring 6 is fixed to the knuckle 3 by connecting the connecting flange 12 to the knuckle 3 with the bolts 7. On the other hand, a part of the outer peripheral surface of the hub 8 is an outer end opening of the outer ring 6 (the term "outside in the axial direction" means a part which is outward in the width direction when assembled to an automobile,
Left side of FIGS. Conversely, the right side of FIGS. 1 and 4, which is the center side in the width direction when assembled to an automobile, is referred to as the inner side in the axial direction. ) Protruding from the mounting flange 13
Is formed. The wheel 1 and the rotor 2 are connected and fixed to one side surface (outside surface in the illustrated example) of the mounting flange 13. For this purpose, mounting holes 14 are formed at a plurality of positions in the circumferential direction of the mounting flange 13 on the same circumference centered on the center axis of the hub 8 and penetrate both side surfaces of the mounting flange 13. are doing. Further, a serration portion 15 is provided on the outer peripheral surface of a portion near the base end (portion near the right end in FIG. 4) of each of the studs 9, and a first half (left half in FIG. 4).
The male screw portion 16 is formed on the outer peripheral surface of each. Then, the serration portion 15 of each stud 9 is press-fitted into each of the mounting holes 14 so that the base end of each stud 9 is mounted on the mounting flange 13.
Is fixed in a state in which rotation with respect to is prevented. The rotor 2 is superimposed on one side of the mounting flange 13, and the wheel 1 is superimposed on one side of the rotor 2. In this state, the tip of each of the studs 9 is inserted through a through hole provided in the wheel 1 and the rotor 2. A nut 10 serving as a coupling member is attached to a male thread 16 provided at the tip of the stud 9 projecting from one side surface of the wheel 1.
And further tightened. With this configuration, the wheel 1 and the rotor 2 are connected and fixed to one side surface of the mounting flange 13. A portion of the double row of outer raceways 11a and 11b facing the outer raceway 11a is a rotation raceway at a middle portion of the outer circumferential surface of the hub 8 which is a rotating raceway. An inner raceway 17a is formed. Further, an inner ring 20, which constitutes a rotating member 19 which rotates when used together with the hub 8, is externally fixed to a small-diameter stepped portion 18 formed on the outer peripheral surface of the inner end of the hub 8. The inner raceway 17b, which is also a rotating raceway, formed on the outer circumferential surface of the inner race 20, which is also a rotating circumferential surface, is combined with the outer race 11 of the double row.
a and 11b are opposed to the inner outer raceway 11b. [0007] Between each of the outer raceways 11a, 11b and each of the inner raceways 17a, 17b, a plurality of balls 21, 21 each of which is a rolling element, is provided with a cage 22, 22, respectively.
2 so as to be able to roll freely while being held. With this configuration, a double-row angular contact type ball bearing that is a back-to-back combination is formed, and the rotating member 19 is provided inside the outer ring 6.
Are supported rotatably and capable of supporting radial loads and thrust loads. A seal ring 23 is provided between the inner peripheral surface of both ends of the outer ring 6, the outer peripheral surface of the intermediate portion of the hub 8 and the outer peripheral surface of the inner end of the inner ring 20.
a, 23b are provided to shut off the internal space where the balls 21, 21 are provided from the outside. Further, the illustrated example is a wheel bearing unit 5 for driving wheels (rear wheels of FR and RR vehicles, front wheels of FF vehicles, and all wheels of 4WD vehicles). A hole 24 is formed. The spline shaft 26 of the constant velocity joint 25 is inserted into the spline hole 24. When using the above-described rolling bearing unit 5 for a wheel, as shown in FIG. 4, the outer ring 6 is fixed to the knuckle 3 and the mounting flange 13 of the hub 8 is combined with a tire (not shown). And the rotor 2 which is a rotating body for braking is fixed. Also, the rotor 2 of these,
A disc brake for braking is configured by combining a support and a caliper (not shown) fixed to the knuckle 3. At the time of braking, 1 is provided with the rotor 2 interposed therebetween.
A pair of pads is pressed against both sides of the rotor 2.
In the present specification, the braking friction surface means both axial sides of the rotor when the rotating body for braking is a rotor, and when the rotating body for braking is a drum constituting a drum brake. Refers to the inner peripheral surface of this drum. [0009] On the other hand, it is known that vibrations accompanied by unpleasant noise, often called judder, are often generated when braking an automobile. Various causes are known as the cause of such vibration, such as uneven friction between the side surface of the rotor 2 and the pad lining, but the runout of the rotor 2 is also known to be a major cause. Have been. In other words, the side surface of the rotor 2, which is the friction surface for braking, should be perpendicular to the center of rotation of the rotor 2; . As a result, it is unavoidable that the side surface of the rotor 2 swings in the direction of the rotation axis (the left-right direction in FIG. 4) when the vehicle is running, albeit somewhat. When such vibration (the amount of displacement in the left-right direction in FIG. 4) increases, the judder occurs when the linings of a pair of pads are pressed against both side surfaces of the rotor 2 for braking. When a drum constituting a drum brake is fixed to the side surface of the mounting flange 13, if the inner peripheral surface of the drum is not completely parallel to the rotation center of the drum, the inner peripheral surface of the drum is When the shoe is pressed, vibration like a judder also occurs. In order to suppress the judder generated due to such a cause, the axial vibration of the side surface of the rotor 2 (axial vibration) or the radial vibration of the inner peripheral surface of the drum 2 is suppressed (improved). Things matter. In order to suppress this run-out, the perpendicularity of the mounting surface for fixing the rotor 2 in a state where the rotor 2 is in contact with one side surface of the mounting flange 13 with respect to the rotation center of the hub 8 is improved. It is important to ensure sufficient shape accuracy of the mounting surface. [0011] Conventionally, it has been common practice to make almost one side of the mounting flange 13 for fixing a rotating body for braking such as the rotor 2 into a flat surface having no irregularities. It is being done. Almost the entire surface of one side of the mounting flange 13 serves as a mounting surface for fixing the rotor 2 in contact therewith. For this reason, in the case of the conventional structure, the area of the mounting surface is relatively large.
Therefore, not only is the processing work for finishing the mounting surface in a predetermined shape and dimensions complicated, but also the time required for the processing work is lengthened, which causes the cost of the wheel bearing unit 5 to increase. The hub 8 is connected to the wheel bearing unit 5.
While the vehicle is being transported to be combined with the other components, or the completed wheel bearing unit 5 is being transported to be assembled into an automobile, a part of one side of the mounting flange 13 collides with another component. There is a possibility that irregularities such as dents may be formed due to such factors. In the case of the conventional structure as described above, almost the entire surface of one side of the mounting flange 13 is used as a mounting surface for fixing the rotor 2. Are easily formed on this mounting surface. If the projections and depressions are formed on the mounting surface, the braking friction surface of the braking rotating body such as the rotor 2, which is fixed in a state of contacting the mounting surface, oscillates. It is difficult to prevent the occurrence of the occurrence. or,
If the braking friction surface oscillates, there is a possibility that uneven wear may occur on the braking friction members such as pads and shoes that are pressed against the braking friction surface during braking. The wheel bearing unit of the present invention has been invented in view of such circumstances. [0013] A wheel bearing unit according to the present invention comprises a stationary wheel which has a stationary track on a stationary peripheral surface and does not rotate during use, similarly to the above-described conventional structure. A rotating member having a rotating side track on the rotating side peripheral surface and rotating during use, a mounting flange provided on the outer peripheral surface of the rotating member, and a mounting hole formed so as to penetrate the mounting flange in the axial direction. And a plurality of rolling elements provided between the stationary track and the rotating track. Then, at the time of use, the rotating body for braking is fixedly connected to one side surface of the mounting flange so as to overlap the mounting flange. In particular, in the wheel bearing unit of the present invention, an annular projection formed at a radially intermediate portion on one side surface of the mounting flange so as to protrude in the axial direction over the entire circumference of the mounting flange. It has a part. One end of the mounting hole in the axial direction is open on the side surface of the annular projection. In the case of the wheel bearing unit of the present invention constructed as described above, the mounting surface for fixing the rotating body such as the rotor in contact with one side of the mounting flange is provided. Only the side surface of the annular projection is provided. Therefore, in the case of the present invention, the area of the mounting surface can be reduced. Accordingly, a working operation for finishing one side surface of the mounting flange into a predetermined shape and dimensions can be easily performed, and the time required for the working operation can be shortened, thereby reducing the manufacturing cost of the wheel bearing unit. In addition, even when the wheel bearing unit of the present invention is transported, the mounting surface for fixing the rotating body for braking in the abutted state is small, so that the mounting surface can be connected to other parts. Unevenness due to collision or the like can be hardly formed.
Therefore, it is possible to reduce the runout of the braking friction surface of the braking rotary body fixed to the mounting flange. As a result, according to the present invention, it is possible to sufficiently suppress the occurrence of judder at the time of braking of the automobile and the occurrence of uneven wear on the braking friction member such as a pad that is pressed against the braking friction surface. 1 to 3 show a first embodiment of the present invention. The feature of the present invention is that the manufacturing cost of the wheel bearing unit is reduced, and at the same time, the braking rotation of the rotor 2 (FIG. 4) and the like fixed to one side of the mounting flange 13a provided on the outer peripheral surface of the rotating member. The point is that the shape of the one side surface of the mounting flange 13a is devised in order to suppress the body shake. The basic structure and operation of the other wheel bearing units are the same as those of the conventional structure shown in FIG. 4 described above, and therefore, duplicated illustration and description are omitted or simplified. The following description focuses on the differences from the conventional structure described above. On the outer peripheral surface of the hub 8a, which constitutes a rotating member together with the inner ring 20 (FIG. 4), a wheel 1 constituting a wheel is provided.
(FIG. 4), and a mounting flange 13a for fixing the rotor 2 or the drum which is a rotating body for braking is provided. At a plurality of positions in the circumferential direction of the mounting flange 13a, mounting holes 14 and 14 are formed on the same circumference centered on the rotation center of the hub 8a.
14, a serration portion 15 (FIG. 4) provided at a portion near the base end of the stud 9 is press-fittable. or,
Chamfers 27 are formed at both ends of the mounting holes 14 in the axial direction. Also, the conventional wheel bearing unit 5 shown in FIG. 4 is provided with drive wheels (FR wheels and RR vehicles, rear wheels, FF wheels).
While this was for supporting the front wheels of a car and all the wheels of a 4WD car, the wheel bearing unit of the present example is used for driven wheels (front wheels of FR and RR cars, rear wheels of FF cars). It is for supporting. For this reason, in the case of this example, unlike the above-described conventional structure, a spline hole 24 (see FIG. 4) for inserting the spline shaft 26 of the constant velocity joint 25 into the center of the hub 8a. Without forming the hub 8a
Is a solid state. In particular, in the case of the present invention, an annular convex portion 28 is provided at a radially intermediate portion of the axially outer surface (the left surface in FIG. 1) of the mounting flange 13a, and an axially extending portion is formed around the entire circumference of the mounting flange 13a. (Left side of FIG. 1). The axially outer surface (the left surface in FIG. 1) of the annular projection 28 is a plane perpendicular to the rotation center of the hub 8a. For this reason, at the time of manufacturing the hub 8a, while rotating the hub 8a around its central axis, a precision machining tool is hit against the axially outer surface of the annular projection 28, and turning is performed. The outer surface in the axial direction is finished to a predetermined shape and dimensions. In addition, each of the mounting holes 14, 1
An outer end in the axial direction of FIG. 4 (the left end in FIG. 1) is opened on the outer surface in the axial direction of the annular projection 28. The rotating member is provided with such a hub 8.
The inner ring 20 is externally fitted and fixed to a small-diameter stepped portion 18 formed at the inner end in the axial direction of FIG. Then, the wheel bearing unit of the present invention is configured such that the serration portion 15 provided near the base end of each of the studs 9 is press-fitted and fixed to each of the mounting holes 14, 14, and the rotating member, the outer race 6 and the ball are fixed. 21 (FIG. 4) and other components of the wheel bearing unit. In the case of the wheel bearing unit of the present invention configured as described above, the axially outer surface of the mounting flange 13a is
An attachment surface for fixing the rotating body for braking such as the rotor 2 in contact with the annular rotating portion 28 shown in FIG.
Only the outer surface in the axial direction. Therefore, in the case of the present invention, the area of the mounting surface can be reduced. Accordingly, a working operation for finishing the outer surface in the axial direction of the mounting flange 13a into a predetermined shape and dimensions can be easily performed, and the time required for the working operation can be reduced, thereby reducing the manufacturing cost of the wheel bearing unit. Can be achieved. Moreover, even when the wheel bearing unit of the present invention is transported, the mounting surface of the mounting flange 13a for fixing the braking rotary member in a contact state is small because the area of the mounting surface is small. Irregularities due to collision with other components or the like can be less likely to be formed on the surface. Accordingly, it is possible to sufficiently suppress the vibration of the braking friction surface of the braking rotary body fixed to the axially outer surface of the mounting flange 13a. As a result, according to the present invention, it is possible to sufficiently suppress the occurrence of judder at the time of braking of the automobile and the occurrence of uneven wear on the braking friction member such as a pad that is pressed against the braking friction surface. Although not shown, the mounting flange 13 is not shown.
The mounting hole formed in a is a screw hole, and a bolt inserted through a through hole provided in the braking rotary body such as the rotor 2 is screwed into the screw hole, and further tightened, so that the braking rotary body and The present invention can also be implemented by a structure that couples and fixes the mounting flange. In the case of this example, a stationary wheel that does not rotate during use is used as the outer ring 6, and a rotating member that rotates during use is provided inside the outer ring 6. However, the present invention is not limited to such a structure, and may be implemented with a structure in which a stationary wheel is used as an inner ring and a rotating member is provided around the inner ring. Since the wheel bearing unit of the present invention is constructed and operates as described above, unpleasant noise and vibration generated during braking can be sufficiently suppressed, and the production of the wheel bearing unit can be achieved. Cost can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial sectional view showing a hub constituting a first example of an embodiment of the present invention. FIG. 2 is a diagram viewed from the left side of FIG. 1; FIG. 3 is an enlarged view of a portion A in FIG. 2; FIG. 4 is a sectional view showing an example of an assembled state of the wheel bearing unit. [Description of Signs] 1 Wheel 2 Rotor 3 Knuckle 4 Support hole 5 Wheel bearing unit 6 Outer ring 7 Bolt 8, 8a Hub 9 Stud 10 Nut 11a, 11b Outer ring track 12 Coupling flange 13, 13a Mounting flange 14 Mounting hole 15 Serration 16 Male thread portion 17a, 17b Inner ring raceway 18 Small diameter step portion 19 Rotating member 20 Inner ring 21 Ball 22 Cage 23a, 23b Seal ring 24 Spline hole 25 Constant velocity joint 26 Spline shaft 27 Chamfer 28 Annular convex portion

Claims (1)

Claims: 1. A stationary wheel having a stationary track on a stationary peripheral surface and not rotating during use, and a rotating member having a rotating track on a rotating peripheral surface and rotating during use. And a mounting flange provided on the outer peripheral surface of the rotating member; a mounting hole formed so as to penetrate the mounting flange in the axial direction; and a plurality of mounting holes provided between the stationary side track and the rotating side track. In the wheel bearing unit having a plurality of rolling elements, and a braking rotary body being fixed to one side of the mounting flange during use, and being coupled and fixed in a state of being superimposed on the mounting flange, a diameter of one side of the mounting flange is provided. An annular projection formed in the middle part in the direction so as to protrude in the axial direction over the entire circumference of the mounting flange, and one end in the axial direction of the mounting hole is opened on a side surface of the annular projection. A rotating member characterized by the above-mentioned.