JP2003240029A - Bearing unit for wheel and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve squareness of a mounting surface 25, namely an outer surface of a rotation side flange 15b for the rotation center of a hub 8b in a third generation structure where a first inner raceway track 16 is directly formed on the outer peripheral surface of the intermediate part of a hub body 13b, and to reduce judder occurring at braking. <P>SOLUTION: The rotation side flange 15b has a plurality of screw holes 33 for screwing bolts for fixing a wheel. After assembling respective components of a bearing unit 5b for the wheel, finishing of the mounting surface 25 is performed by rotating and grinding the hub 8b. Therefore, a size error and a mounting error for each component have no affect on the squareness. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wheel bearing unit for supporting a vehicle wheel and a braking rotor such as a rotor or a drum, and an improvement in a method for manufacturing such a wheel bearing unit.

[0002]

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 the knuckle 3 constituting the suspension device, for example, by the structure shown in FIG. That is, in the circular support hole 4 portion formed in the knuckle 3, the outer ring 6 that constitutes the wheel bearing unit 5 that is the subject of the present invention,
It is fixed by a plurality of bolts 7. On the other hand, the wheel 1 and the rotor 2 are coupled and fixed to the hub 8 constituting the wheel bearing unit 5 by a plurality of studs 9 and nuts 10.

A double row outer ring raceway 1 is formed on the inner peripheral surface of the outer ring 6.
1a and 11b are formed, and a fixed side flange 12 is formed on the outer peripheral surface. The outer ring 6 is fixed to the knuckle 3 by connecting the fixed side flange 12 to the knuckle 3 with the bolts 7.

On the other hand, the hub 8 is the hub body 1
3 and the inner ring 14 are combined. Of a part of the outer peripheral surface of the hub body 13 of these, the outer end opening of the outer ring 6 (the outer side in the axial direction means a portion which is on the outer side in the width direction when assembled in an automobile, and is shown in FIGS. , 6, 7, 8 on the left side, and the upper side of FIGS. 4, 9. On the contrary, the right side of FIGS. 1, 2, 5, 6, 7, 8 and FIG. The lower side 9 is referred to as the inner side with respect to the axial direction, and is the same throughout the present specification. The wheel 1 and the rotor 2 are joined and fixed to one side surface (outer surface in the illustrated example) of the rotary side flange 15 by the studs 9 and the nut 10. Further, on the outer peripheral surface of the intermediate portion of the hub body 13, a portion of the double row outer ring raceways 11a, 11b facing the outer outer ring raceway 11a is provided with the first inner ring raceway 1
6 is directly formed on the hub body 13. Further, the inner ring 14 is externally fitted and fixed to the small diameter step portion 17 formed on the outer peripheral surface of the inner end portion of the hub body 13 to form the hub 8. The second inner ring raceway 18 formed on the outer peripheral surface of the inner ring 14 is replaced with the double-row outer ring raceways 11a, 1
It faces the inner ring raceway 11b of 1b.

These outer ring raceways 11a, 11b and the first,
Between the second inner ring raceways 16 and 18, a plurality of balls 19 and 19 each of which is a rolling element are rotatably provided while being held by cages 20 and 20, respectively. With this configuration, a double-row angular type ball bearing, which is a combination of the back surfaces, is configured, and the hub 8 is rotatably supported inside the outer ring 6 so as to be rotatable and capable of bearing a radial load and a thrust load. It should be noted that seal rings 21a and 21b are provided between the inner peripheral surfaces of both ends of the outer ring 6, the outer peripheral surface of the intermediate portion of the hub body 13 and the outer peripheral surface of the inner end of the inner ring 14, respectively. The internal space provided with 19, 19 is cut off from the outside. Further, in the illustrated example, the driving wheels (the rear wheels of the FR and RR vehicles, the front wheels of the FF vehicle,
Since it is a wheel bearing unit 5 for all wheels of a 4WD vehicle,
A spline hole 22 is formed in the center of the hub body 13. Then, the spline shaft 24 of the constant velocity joint 23 is inserted into the spline hole 22.

When the bearing unit 5 for a wheel as described above is used, as shown in FIG. 8, the outer ring 6 is fixed to the knuckle 3, and the rotation side flange 15 of the hub body 13 is combined with a tire (not shown). 1 and the rotor 2 are fixed. Further, the rotor 2 of these is combined with a support and a caliper (not shown) fixed to the knuckle 3 to form a disc brake for braking. During braking, a pair of pads that sandwich the rotor 2 are pressed against both side surfaces of the rotor 2, which are friction surfaces for braking.
In the present specification, the term "friction surface for braking" refers to both axial side surfaces of the rotor when the rotating body for braking is a rotor, and this drum is used when the rotating body for braking is a drum. Say the inner surface of.

On the other hand, it is known that when braking an automobile, a vibration called a judder often causes an unpleasant noise. Various causes such as non-uniform frictional state between the side surface of the rotor 2 and the pad lining are known as causes of such vibration, and it is also known that the above-mentioned vibration of the rotor 2 is a major cause. Has been. That is, this rotor 2
The side surface of (1) should be perpendicular to the center of rotation of the rotor 2, but it is difficult to form a right angle due to unavoidable manufacturing errors. As a result, it is inevitable that the side surface of the rotor 2 swings in the direction of the rotation axis (the left-right direction in FIG. 8) while the vehicle is running. When such a shake (amount of displacement in the left-right direction in FIG. 8) increases,
The judder occurs when a pair of pad linings are pressed against both sides of the rotor 2 for braking.
Further, when the drum constituting the drum brake is fixed to the side surface of the rotary side flange 15, if the inner peripheral surface of the drum is not completely parallel to the rotation center of the drum, the shoe is attached to the inner peripheral surface. When pressed, vibration like judder still occurs.

In order to suppress the judder caused by such a cause, it is necessary to suppress (improve) the axial runout of the side surface of the rotor 2 (axial runout) or the radial runout of the inner peripheral surface of the drum. Is important. In order to suppress this shake, it is important to improve the squareness of the mounting surface of the rotary side flange 15 (one side surface of the rotary side flange 15) with respect to the center of rotation of the hub body 13. U.S. Pat. No. 6,071,180 describes a method of manufacturing a wheel bearing unit for improving the squareness of a mounting surface of a rotary side flange.

In the case of the wheel bearing unit manufactured by the manufacturing method described in the above-mentioned US patent specification, as shown in FIG. 9, a wide small-diameter step portion 17a formed at the middle portion or inner end portion of the hub body 13a. A pair of inner rings 14 a and 14 b are fitted on the outer side of the inner ring 14 and are held by a nut 29. Further, tapered rollers 30, 30 are used as rolling elements. Like this
The hub body 13a has a hub 8a in which a pair of inner rings 14a and 14b are fitted onto the hub body 13a, and the perpendicularity of the mounting surface 25 of the rotary side flange 15a of the wheel bearing unit 5a is improved. For the method, FIGS.
As shown in FIG. 1, first, the respective constituent members of the wheel bearing unit 5a including the hub 8a before processing the mounting surface 25 are assembled.

Then, the fixed side flange 12 provided on the outer peripheral surface of the outer ring 6 is fixed to the support base 26 of the processing apparatus, and then the hub 8a is rotated by the spindle 27 while the mounting surface 25 of the rotary side flange 15a is being rotated. The tip end surface of the grindstone 28 is abutted against and the mounting surface 25 is finished into a predetermined shape and size. By such a method, the wheel bearing unit 5a
In the case where the mounting surface 25 is manufactured, the squareness of the mounting surface 25 with respect to the rotation center of the hub 8a can be improved regardless of the dimensional error and the assembly error which are unavoidable in the manufacturing of the respective constituent members. It is possible to suppress the swing of the braking friction surface of the rotary braking body such as the rotor 2 (see FIG. 8) fixed to.

However, the above-mentioned US Pat. No. 6,071,1
In the case of the method for manufacturing a wheel bearing unit described in the specification of No. 80, since the finishing process of the mounting surface 25 of the rotary side flange 15a is performed by the grinding process using the grindstone 28, the quality of the wheel bearing unit is improved. It is difficult to secure enough. That is, since the grinding process is performed by rotating the grindstone 28 while the grindstone 28 is pressed against the mounting surface 25, the temperature of the rotary side flange 15a rises during the machining. In order to prevent the rotation-side flange 15a from being distorted due to this temperature rise, it is necessary to grind the mounting surface 25 while supplying a grinding liquid to the processed portion.

However, when the mounting surface 25 is ground while the grinding fluid is supplied after assembling the constituent members of the wheel bearing unit 5a, the grinding fluid causes the tapered rollers 30, 30 as rolling elements. There is a possibility of entering the inside space 31 of the wheel bearing unit 5a in which If it enters, it deteriorates the grease enclosed in the internal space 31 and causes the durability of the wheel bearing unit to be impaired. Moreover, since fine cutting chips and grindstone powder generated by the grinding process are mixed in the grinding fluid entering the internal space 31, these cutting chips and grindstone powder are applied to the rolling surfaces of the tapered rollers 30, 30. And outer ring raceways 11c, 11c and first and second inner ring raceways 16a, 18
This will damage a and significantly reduce the durability of the wheel bearing unit 5a.

Further, when the mounting surface 25 is ground by the cup-shaped grindstone 28 as shown in FIGS. 9 to 10, the friction area between the tip surface of the grindstone 28 and the mounting surface 25 increases, The rotation resistance of the grindstone 28 is large and easily becomes unstable. As a result, there is a possibility that the finishing accuracy of the mounting surface 25 cannot always be sufficiently ensured. Further, when a high degree of rotational balance is required as in a high performance vehicle, it may be required to finish not only one side surface of the rotary side flange 15a but also the outer peripheral edge of the rotary side flange 15a. With the method using, it is not possible to finish the outer peripheral edge as it is. Processing work becomes troublesome.

Further, it is common to press-fit and fix the base end portions of the studs 9 and 9 (see FIG. 8) for fixing the wheel and the braking rotary body to the rotary side flange 15a.
At the time of press-fitting and fixing, the mounting surface 25 may be deformed. Regardless of such deformation, in order to secure the accuracy of the mounting surface 25, it is conceivable that the finishing processing of the mounting surface 25 is performed after the studs 9 and 9 are press-fitted and fixed. It is difficult to perform the grinding process using the above method after the press-fitting and fixing because the grindstone interferes with the studs 9 and 9.

On the other hand, although not shown, in WO 00/74883 A1, the mounting surface of the rotary side flange is finished by a cutting tool while rotating the hub including the rotary side flange. The method of processing is described. Further, US Pat. No. 6,158,124 describes a method in which a rotor is coupled and fixed to a mounting surface of a rotary side flange, and then both side surfaces of the rotor are finished by a cutting tool. In the case of the inventions described in these international publications and US patent specifications, since the finishing of the target surface is performed using a cutting tool, it is described in the above-mentioned US Pat. No. 6,071,180. It is believed that the inconveniences of the above inventions can be eliminated.

[0016]

However, the international publication WO 0
0/74883 A1 Publication and US Patent No. 6,158,12
Also in the case of the invention described in the specification No. 4, there is room for improvement in order to realize the performance improvement of the wheel bearing unit having the structure which has been widely spread in recent years at low cost. This point will be described below.

First, in the case of the invention described in WO 00/74883 A1, in the case of the invention described in US Pat. No. 6,071,180 shown in FIGS. Similarly, in order to provide the first and second inner ring raceways on the outer peripheral surface of the hub, a pair of inner rings is externally fitted and fixed to the hub body,
It is intended for so-called second-generation wheel bearing units.
In the case of such a structure, the outer peripheral surface of the wide small-diameter step portion formed on the hub body for fitting the pair of inner rings to each other has a diameter that changes over substantially the entire length of the portion where the inner rings are fitted to each other. do not do,
It is a single cylindrical surface. Such a single cylindrical surface is relatively easy to machine. Therefore, a pair of inner rings having the same diameter are fitted onto the small-diameter stepped portion so that the first and second inner rings are attached to the outer peripheral surface of the hub. When the inner ring raceways are provided, it is easy to ensure the parallelism of these two inner ring raceways with respect to the center of rotation as long as the accuracy of the pair of inner rings can be secured. Therefore, the bearing unit for a second-generation wheel can be less likely to cause significant judder without performing the method according to the invention described in WO 00/74883 A1. Due to the increase in the number of components, the number of vehicles adopted has gradually decreased in recent years.

On the other hand, as shown in FIG.
In the case of a so-called third-generation wheel bearing unit in which the first inner ring raceway 16 is directly formed on the outer peripheral surface of the intermediate portion of the hub 8,
The first inner ring raceway 16 is provided at an axially intermediate portion of the hub body 13.
And the inner ring 1 provided with the second inner ring raceway 18
The small diameter step portion 17 for externally fitting and fixing 4 has a stepped shape. Therefore, compared to the second-generation wheel bearing unit, judder is more likely to occur due to the deterioration of the parallelism of the first and second inner ring raceways 16 and 18, and a countermeasure is desired.
The invention described in International Publication WO 00/74883 A1 is not intended for the third-generation wheel bearing unit.

In contrast, the above-mentioned US Pat. No. 6,15
Although the invention described in the specification of No. 8,124 is intended for the third-generation wheel bearing unit, the subject of finishing processing is not the mounting surface of the rotary side flange but the both side surfaces of the rotor. Since the diameter of this rotor is larger than the diameter of the rotary side flange, when finishing both sides of the rotor, it is inevitable that the processing apparatus becomes large and the cost increases accordingly. The bearing unit for a wheel of the present invention and the method for manufacturing the same are invented in view of such circumstances.

[0020]

In the wheel bearing unit and the manufacturing method thereof according to the present invention, the wheel bearing unit according to claim 1 is a wheel and a braking unit, like the above-mentioned conventional wheel bearing unit. A bearing unit for a wheel for rotatably supporting a rotating body for use with a suspension device, comprising an outer ring, a hub, and a plurality of rolling elements. The outer ring of these has a double row outer ring raceway on its inner peripheral surface, and does not rotate while being supported by the suspension device during use. The hub is composed of a hub body and an inner ring. Of these, the hub body includes a rotary side flange formed on the outer end of the outer peripheral surface and having one axial surface thereof as a mounting surface for supporting the braking rotating body, and an axial intermediate surface of the outer peripheral surface. A first inner ring raceway formed directly on the portion; and a small diameter step formed on the inner circumferential end of the outer peripheral surface in the axial direction. The inner ring has a second inner ring raceway formed on the outer peripheral surface thereof, and is fixed to the hub body while being fitted onto the small-diameter step portion.
A plurality of each rolling element is provided between each outer ring raceway and each of the first and second inner ring raceways so that they can roll freely. Particularly, in the bearing unit for a wheel of the present invention, the rotary side flange has screw holes penetrating in the axial direction at a plurality of circumferential positions, and the mounting surface of the rotary side flange is at least The outer ring, the hub, and the plurality of rolling elements are assembled, and then machined into a predetermined shape and size.

A method of manufacturing a wheel bearing unit according to a fourth aspect of the present invention is a method of manufacturing the wheel bearing unit as described above, wherein after the outer ring, the hub and the plurality of rolling elements are assembled together. While rotating the hub with respect to the outer ring, the mounting surface of the rotary side flange is machined into a predetermined shape and size by turning.

[0022]

In the case of the wheel bearing unit and the method of manufacturing the same of the present invention configured as described above, after the outer ring, the hub and the plurality of rolling elements are assembled, they are provided on the outer peripheral surface of the outer end portion of the hub.
The mounting surface of the rotating-side flange for fixing the braking rotating body in a fixed manner is machined into a predetermined shape and size. Therefore, the squareness of the side surface of the rotation-side flange with respect to the rotation center of the hub is irrespective of the dimensional error and the assembly error that are unavoidable in the manufacturing of the respective constituent members, which are likely to occur particularly in the third-generation wheel bearing unit. By increasing the height, it is possible to suppress the deflection of the braking friction surface of the braking rotor fixed to the rotating side flange.

In addition, in the case of the present invention, since the side surface of the rotary side flange is machined by turning or the like, it is not necessary to pour the grinding liquid into the portion to be machined, and so-called dry machining is possible. In addition, the processing scraps generated by the processing become continuous in the form of threads and are less likely to be scattered around. Therefore, it becomes difficult for foreign matter such as grinding fluid and processing dust to enter the internal space of the wheel bearing unit, and it is unlikely that the durability of the wheel bearing unit is impaired due to finishing of the rotary flange. it can. Further, since the frictional force acting between the processing tool and the side surface of the rotary side flange at the time of turning processing is limited, it is possible to perform the processing in a stable state, and the rotation side flange is less likely to be distorted. . Further, finishing processing of the outer peripheral edge of the rotary side flange can be easily performed if necessary. Moreover, even if a screw hole is formed in the rotary side flange, there is no protruding portion such as a stud, so that the mounting surface can be easily processed.

[0024]

1 to 3 show a first example of an embodiment of the present invention. The wheel bearing unit 5b manufactured by the manufacturing method of this example is provided with a fixed side flange 12 for fixing the outer ring 6 to the knuckle 3 (FIG. 8) on the outer peripheral surface of the intermediate portion of the outer ring 6. In addition, double rows of outer ring raceways 11a and 11b are formed on the inner peripheral surface of the outer ring 6.
In addition, first and second inner ring raceways 16 and 18 are provided on the outer peripheral surfaces of the hub body 13b and the inner ring 14 that form the hub 8b, respectively, at portions facing the outer ring raceways 11a and 11b. That is, the first inner ring raceway 16 is formed directly on the outer peripheral surface of the intermediate portion of the hub body 13b, and the hub body 1
The inner ring 14 having a second inner ring raceway 18 formed on the outer peripheral surface thereof is externally fitted to the small-diameter step portion 17 formed near the inner end of 3b. Then, the inner ring 14 has the small-diameter step portion 17
A caulking portion 32 is formed at the inner end of the hub body 13b to prevent the hub body 13b from coming off. That is, after the inner ring 14 is fitted onto the small-diameter step portion 17, the hub body 1
A portion of the inner end portion 3b protruding from the inner end surface of the inner ring 14 is plastically deformed outward in the radial direction to form the caulked portion 32. The caulked portion 32 suppresses the inner end surface of the inner ring 14. . With this configuration, the inner ring 14 is externally fitted and fixed to the inner end portion of the hub body 13b, and the hub 8 is
b.

Further, at a portion of the outer peripheral surface of the hub body 13b near the outer end, which is projected from the outer end opening of the outer ring 6, a wheel 1 constituting a wheel and a rotor 2 as a rotating body for braking (see FIG. 8) Alternatively, a rotary side flange 15b for fixing the drum is provided. Screw holes 33 are formed at a plurality of circumferential positions of the rotation-side flange 15b on the same circumference with the rotation center of the hub body 13b as the center. For example, as shown in FIG. 7, the wheel 1 and the rotor 2 are fixed to the rotary side flange 15b by bolts 55 screwed into the screw holes 33.

Between the outer ring raceways 11a and 11b and the first and second inner ring raceways 16 and 18, a plurality of balls 19 and 19, which are rolling elements, are respectively provided in the cage 20. , 20 are held so that they can roll freely. A pair of seal rings 21a and 21b are 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 body 13b, and the outer peripheral surface of the inner end portion of the inner ring 14, respectively. The internal space 31 in which the balls 19 and 19 are provided is shielded from the outside to prevent leakage of grease filled in the internal space 31 and prevent foreign matter from entering the internal space 31.

Further, in the case of this example, the inner seal ring 21 of the pair of seal rings 21a and 21b is used.
The encoder 35 is fixed to the side surface of the cored bar 34 which is configured as b and is externally fitted and fixed to the inner end portion of the inner ring 14. The encoder 35 is made of a rubber magnet in which S poles and N poles are alternately arranged in the circumferential direction. That is, this encoder 3
Reference numeral 5 is a ring-shaped rubber magnet in which ferrite powder is mixed in rubber and is magnetized in the axial direction. The magnetizing directions are alternately changed at equal intervals in the circumferential direction. Therefore, the S poles and the N poles are alternately arranged at equal intervals in the circumferential direction on the inner side surface of the encoder 35. When the wheel bearing unit 5b is used, the detection portion of a sensor (not shown) supported by a fixed portion such as a part of the suspension device is opposed to the inner surface of the encoder 35 through a minute gap. The output signal of the sensor, which changes according to the rotation speed of the encoder 35, can be taken out. The encoder 35 and the sensor as described above constitute a rotation speed detecting device for detecting the rotation speed of the wheel fixed to the hub body 13b.

The mounting surface 25 which is the outer surface of the rotary side flange 15b provided on the wheel bearing unit 5b as described above.
Is finished by turning into a flat surface perpendicular to the central axis of rotation of the hub body 13b. In this way, prior to performing the turning process on the mounting surface 25 of the rotary side flange 15b, the respective constituent members of the wheel bearing unit 5b are
Except for the mounting surface 25 of the rotary side flange 15b, the rotary side flange 15b is processed into a predetermined shape and size. Also, this rotating side flange 1
The mounting surface 25 of 5b is processed into a rough shape and dimensions. Next, the constituent members of the wheel bearing unit 5b are assembled into the state shown in FIG.

That is, the outer ring 6 and the balls (rolling elements) 19, 19 are assembled around the hub body 13b to form the wheel bearing unit 5b. In other words, the outer ring raceways 11 a, 1 provided on the inner peripheral surface of the outer ring 6
1b and the first and second inner ring raceways 16 and 18 provided on the outer peripheral surfaces of the hub body 13b and the inner ring 14, the plurality of balls 19 and 19 are provided, and the outer ring 6 and the hub body are provided. 13b, the inner ring 14, and the plurality of balls 19, 19 are assembled. In this state, the rotation side flange 15b provided on the outer peripheral surface of the outer end portion of the hub body 13b is located on the outer side in the axial direction of the outer ring 6, and the mounting surface 25 is located on the side opposite to the outer ring 6 in the axial direction. To do. Since a rear surface combination type contact angle is given to each of the balls 19 and 19, the wheel bearing unit 5b can support the radial load and the thrust load applied during traveling. Also, the inner peripheral surfaces of both ends of the outer ring 6, the outer peripheral surface of the intermediate portion of the hub body 13b, and the inner ring 14 are formed.
A pair of seal rings 21a between the inner end and the outer peripheral surface of the
21b is provided.

Then, in this state, the wheel bearing unit 5b to be turned on the mounting surface 25 of the rotary side flange 15b is assembled to the turning device 36. In this case, a portion of the outer peripheral surface of the outer ring 6 that is axially inward of the inner surface of the fixed side flange 12 is the turning device 36.
It is gripped by the tip portion of the chuck 37 constituting the. The tip surface of the chuck 37 (the left end surface in FIGS. 1 and 2) is the inner surface of the fixed-side flange 12 (the surface opposite to the mounting surface 25).
Butt against the inner diameter part of. In the case of this example, the inner peripheral surface of the tip portion of the chuck 37 is made of a sleeve 38 made of a relatively soft material such as synthetic resin, aluminum or copper.
It is composed by. With the outer ring 6 held by the chuck 37, the outer peripheral surface of the outer ring 6 contacts only the inner peripheral surface of the sleeve 38 so that the outer peripheral surface of the outer ring 6 is not damaged.

The tip of the spindle 41 of the turning device 36 is inserted from the outer end side of the hub body 13b into the spline hole 22 provided in the center of the hub body 13b. The male spline portion 42 provided on the outer peripheral surface of the tip portion is spline-engaged with the spline hole 22. Then, the spindle 41 is rotationally driven to rotate the hub body 13b around its central axis, and the precision machining bits 43a and 43b are abutted against the outer side surface of the rotating side flange 15b. Then, the mounting surface 25 is subjected to turning. Then, the mounting surface 25 is finished into a predetermined shape and size. If the machining time may be a little longer, one precision machining tool is sufficient.

As described above, in the case of the wheel bearing unit manufacturing method of the present invention and the wheel bearing unit obtained by this manufacturing method, the hub body is assembled after the respective constituent members of the wheel bearing unit 5b are assembled. Provided on the outer peripheral surface of 13b,
The mounting surface 25, which is the outer surface of the rotating-side flange 15b for fixing the wheel 1 and the rotor 2 (see FIG. 8) to each other, is subjected to turning to finish into a predetermined shape and size. Therefore, irrespective of the dimensional error and the assembly error which are unavoidable in the manufacturing of the respective constituent members, the perpendicularity of the mounting surface 25 with respect to the rotation center of the hub body 13b is increased and fixed to the rotation side flange 15b. It is possible to suppress the shake of both side surfaces, which are friction surfaces for braking of the rotor 2. Particularly in the case of the illustrated example, the inner ring 14 is fixed to the hub body 13b by the caulking portion 32 formed at the inner end portion of the hub body 13b. Therefore, if the perpendicularity of the mounting surface 25 is bad, it becomes impossible to reuse each of the constituent members of the wheel bearing unit 5b (all the parts must be discarded), and the parts cannot be walked. The stay becomes worse. On the other hand, in the case of the present invention, since the perpendicularity of the mounting surface 25 can be always made good, the yield can be made good and the high-quality wheel bearing unit 5b can be manufactured at low cost.

Further, in the case of the present invention, the mounting surface 25, which is the outer surface of the rotary side flange 15b, is machined by turning using the precision machining bits 43a and 43b, so that the machined portion is machined. It is not necessary to pour the grinding fluid onto the certain mounting surface 25, and so-called dry machining is possible. In addition, the processing scraps generated by the processing become continuous in the form of threads and are less likely to be scattered around. For this reason, it becomes difficult for foreign matter such as grinding fluid and processing dust to enter the internal space 31 of the wheel bearing unit 5b which is already assembled from the respective constituent members, and with the finishing of the rotary side flange 15b,
The cause of impairing the durability of the wheel bearing unit 5b can be less likely to occur.

Further, at the time of turning, the frictional force acting between each of the precision machining tools 43a, 43b, which is a machining tool, and the mounting surface 25 is limited. Therefore, the stress applied to the rotary side flange 15b at the time of processing can be suppressed to be small, and the heat generated in the processed portion can be reduced, and the rotation side flange 15b is less likely to be distorted. Therefore, the runout of both side surfaces of the rotor 2 fixed to the rotary side flange 15b can be further suppressed. Further, if necessary, the rotary side flange 15
For the finishing of the outer peripheral edge of b, the wheel bearing unit 5b is also used.
Can be easily performed without attaching / detaching to / from the turning device 36.

Further, in the case of this embodiment, the outer peripheral surface of the outer ring 6 is held by the chuck 37 of the turning device 36, and the outer peripheral surface of the outer ring 6 is inside the sleeve 38 made of a relatively soft material. It is designed to contact only the peripheral surface.
The relatively hard metal part forming the main body of the chuck 37 does not contact the outer peripheral surface of the outer ring 6. Therefore, it is possible to prevent the outer peripheral surface from being damaged by the hard metal portion forming the chuck 37, and it is possible to sufficiently secure the shape accuracy of the outer peripheral surface of this portion. The outer peripheral surface of this portion is a portion that is internally fitted inside the support hole 4 (FIG. 8) of the knuckle 3 when the wheel bearing unit 5b is used, and the shape accuracy of the outer peripheral surface of this portion can be sufficiently ensured. As a result, a part of the outer ring 6 can be fitted and fixed inside the support hole 4 without rattling. Moreover, even if the screw hole 33 is formed in the rotary side flange 15b,
Since there is no protruding part such as the stud 9 (see FIG. 8),
The mounting surface 25 can be easily processed.

Next, FIG. 4 shows a second embodiment of the present invention.
An example is shown. In the case of the present example, the finishing processing of the mounting surface 25 which is the outer surface of the rotary side flange 15b constituting the wheel bearing unit 5c is assembled by mounting the wheel bearing unit 5c on the turning device 36a. 25,
The single precision machining tool 43c is used for continuous machining. In this case, the outer ring 6 is placed on the support base 26a,
The central axis of the spindle 41a is supported and fixed in the vertical direction, and the tip end of the spindle 41a is fitted in the cylindrical portion 44 formed on the outer end of the hub 8c so that torque can be transmitted.
Further, the inner end portion of the inner ring 14 externally fitted and fixed to the inner end portion of the hub 8c is projected beyond the inner end surface of the hub 8c, and the inner end surface of the inner ring 14 is held down by a part of a constant velocity joint (not shown). I am doing it. Further, the encoder as in the first example is not incorporated in the seal ring 21b that closes the inner end opening of the internal space 31. Other configurations and operations are the same as those in the case of the above-described first example, and thus redundant description will be omitted.

Next, FIGS. 5 to 6 show a third example of the embodiment of the present invention. In the case of this example, the hub body 13b
A single cylindrical surface portion 45 is provided on the outer peripheral surface of the rotary side flange 15b provided on the outer peripheral surface of the
Is provided all around. Further, the outer diameter D ₄₅ of the cylindrical surface portion 45 is made larger than the diameter D ₁₂ (FIG. 6) of the circumscribing circle of the fixed side flange 12 (D ₄₅ > D ₁₂ ). Then, as in the case of the first example described above, the wheel bearing unit 5d.
In a state in which the respective constituent members are assembled, the closing member 46 is externally fitted and fixed to the inner end portion of the outer ring 6. The closing member 46 is made of a synthetic resin by injection molding so as to have a cylindrical shape with a bottom. That is, the closing member 46 has a cylindrical portion 47.
And a bottom plate portion 48 that closes the inner end (right end in FIGS. 5 and 6) of the tubular portion 47. In addition, a knob 49 is provided at the center of a side surface of the bottom plate 48 opposite to the cylindrical portion 47. The cylindrical portion 47 is formed by connecting a small-diameter cylindrical portion 50 and a large-diameter cylindrical portion 51, which are concentric with each other, by a step portion 52. Such a closing member 46 is externally fitted and fixed to the small-diameter step portion 53 provided on the outer peripheral surface of the inner end portion of the outer ring 6 during the turning process of the mounting surface 25 which is the outer surface of the rotary side flange 15b. Further, the outer surface of the step portion 52 provided in the middle portion of the cylindrical portion 47 is abutted against the inner end surface of the outer ring 6.

Then, in this state, the rotary side flange 15
The wheel bearing unit 5d to be turned on the mounting surface 25 which is the outer side surface of b is assembled to the turning device 36b. In this case, a portion of the outer peripheral surface of the outer ring 6 between the fixed-side flange 12 and the small-diameter step portion 53 of the chuck 37 that constitutes the turning device 36b, as in the case of the first example described above. Hold by the tip.

Further, in the case of the present embodiment, the base end portion of the cylindrical cover 54, which is made of a metal plate such as a steel plate or synthetic resin and whose inner and outer peripheral surfaces are simply cylindrical surfaces, is provided with the turning device 36b.
Fixed to a part of. The inner diameter d ₅₄ (FIG. 2) of the cover 54 is slightly larger than the outer diameter D ₄₅ of the cylindrical surface portion 45 (d ₅₄ > D ₄₅ ). Wheel bearing unit 5
When d is installed in the turning device 36b, the wheel bearing unit 5d in which the closing member 46 is fixed to the inner end portion of the outer ring 6 is placed inside the cover 54, and the closing member 46 is placed first. Insert in the state where it was set to. The cover 54 covers the periphery of a portion extending from the outer diameter side of the axially intermediate portion of the cylindrical surface portion 45 provided on the rotation side flange 15b to the outer diameter side of the inner end of the closing member 46. The outer end portion of the rotary side flange 15b and the outer end portion of the hub 8a are not inserted into the inside of the cover 54 but protruded from the outer end of the cover 54. Then, in the same manner as in the case of the above-described first example, two precision processing bits 43a and 43b are provided on the mounting surface 25 which is the outer surface of the rotary side flange 15b.
The mounting surface 25 is subjected to a turning process. Then, the mounting surface 25 is finished into a predetermined shape and size.

Particularly in the case of this example, this mounting surface 25 is added.
It is provided on the outer peripheral surface of the rotary side flange 15b when working.
From the outer diameter side of the cylindrical surface portion 45 to the outer diameter side of the inner end of the outer ring 6
A cylindrical cover 54 covers the periphery of the
It The outer diameter of the outer peripheral surface of the rotating side flange 15b is
If a single cylindrical surface portion 45 is provided at the largest portion,
Together, the outer diameter D of the cylindrical surface portion 45₄₅The fixed side flange
Diameter D of 12 circumscribed circles ₁₂Larger than (D₄₅>
D₁₂). For this reason, the circumference of the above-mentioned predetermined portion is formed into the cylindrical shape.
Even if it is covered with the cover 54, this cover 54 and the above fixing
Prevents interference with the side flange 12, and
The inner peripheral surface of the cover 54 and the cylinder of the rotation side flange 15b
The gap between the outer peripheral surface of the surface portion 45 can be made sufficiently small.
The screw hole 33 is on the opposite side of the mounting surface 25 (inner side).
Surface side), a key made of an elastic material such as rubber or synthetic resin.
The cap 39 is closed by fitting or the like.

Therefore, during turning of the mounting surface 25, which is the outer surface of the rotary side flange 15b, foreign matter such as chips generated during turning is inside the internal space 31 in which the plurality of balls 19, 19 are provided. Enter each seal ring 21
It is possible to sufficiently prevent the a and 21b from being damaged by the foreign matter. As a result, the durability of the wheel bearing unit 5d can be sufficiently ensured, and foreign matter such as cutting chips of a magnetic material is prevented from adhering to the encoder 35, which is a permanent magnet, to prevent the wheel fixed to the hub 8a. The accuracy of rotation speed detection can be improved. In addition, a dynamic pressure groove is formed in the cylindrical surface portion 45, and as the rotary side flange 15b rotates, a gap is formed between the cylindrical surface portion 45 and the inner peripheral surface of the cover 54 from the inside to the outside of the cover 54. By inducing the flow, it is possible to more reliably prevent foreign matter from entering the internal space 31.

Further, in the case of the present embodiment, the closing member 46 is externally fitted and fixed to the inner end portion of the outer ring 6 when the mounting surface 25 which is the outer surface of the rotary side flange 15b is turned.
For this reason, the outer ring 6 and the hub 8 are combined with the fact that a part of the bearing unit 5d for wheels is covered with the cylindrical cover 54.
It is possible to more reliably prevent foreign matter from entering the inside space 31 from the inner end side of a. When the turning process is completed, the turning device 36b moves the wheel bearing unit 5
d is removed, and further, the closing member 46 is removed from the inner end portion of the outer ring 6. In this way, the operation of removing the closing member 46 is performed by the operator with the knob 49 provided on the closing member 46.
It can be easily done by pulling. Moreover, the work of attaching and detaching the closing member 46 to and from the outer ring 6 can be performed at a place sufficiently distant from the turning device 36b, so that foreign matter can be sufficiently prevented from entering the internal space 31.

Unlike the case of this example, the closing member 4 is
Instead of omitting 6, the base end portion of a cylindrical second cover (not shown) is fixed to a part of the turning device 36b, and the tip end portion of the second cover is fixed when turning is performed. The outer ring 6 can also be fitted onto the inner end portion of the outer ring 6. Even in this case, foreign matter can be sufficiently prevented from entering the inner space 31 from the inner end sides of the outer ring 6 and the hub 8a, as in the case of the present example using the closing member 46.
When the second cover is externally fitted to the inner end portion of the outer ring 6 as described above, the second cover is used in order to facilitate the external fitting work of the second cover. It is preferable to fit the inner end portion of the outer ring 6 with a clearance fit. Even when the second cover is fitted to the outer ring 6 by a clearance fit as described above, since the base end portion of the second cover is fixed to a part of the turning device 36b, the The second cover never comes off from the inner end of the outer ring 6. Since the configuration and operation of the other parts are the same as those in the case of the first example shown in FIGS. 1 to 3 described above, the same parts are designated by the same reference numerals, and the duplicate description will be omitted.

[0044]

Since the wheel bearing unit and the manufacturing method thereof according to the present invention are configured and operate as described above, a third-generation wheel bearing unit having a small number of parts can be obtained.
Unpleasant noise and vibration generated during braking can be sufficiently suppressed at low cost.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first example of an embodiment of the present invention in a state in which a side surface of a rotary side flange is subjected to a turning process.

2 is a partially enlarged sectional view of FIG.

FIG. 3 is a view of the hub as viewed from the left side of FIG. 1, omitting a spindle for rotationally driving the hub.

FIG. 4 is a view similar to FIG. 1, showing a second example of the embodiment of the present invention.

FIG. 5 is a view similar to FIG. 1 showing the third example.

6 is a partially enlarged sectional view of FIG.

FIG. 7 is a partial cross-sectional view showing a state in which the wheel and the rotor on the side surface of the rotary side flange are fixed.

FIG. 8 is a cross-sectional view showing an example of an assembled state of a wheel bearing unit that is a target of the present invention.

FIG. 9 is a partial cross-sectional view showing an example of a conventional technique in a state where a side surface of a rotary side flange is ground.

FIG. 10 is a partially cutaway view from above in FIG. 9;

[Explanation of symbols]

1 wheel 2 rotor 3 knuckles 4 Support holes 5, 5a, 5b, 5c, 5d Wheel bearing unit 6 outer ring 7 volts 8, 8a, 8b, 8c hub 9 studs 10 nuts 11a, 11b, 11c Outer ring raceway 12 Fixed side flange 13, 13a, 13b Hub body 14, 14a, 14b Inner ring 15, 15a, 15b Rotating side flange 16, 16a First inner ring raceway 17, 17a Small diameter step 18, 18a Second inner ring raceway 19 balls 20 cage 21a, 21b Seal ring 22 Spline hole 23 constant velocity joint 24 spline shaft 25 Mounting surface 26, 26a support base 27 spindles 28 whetstone 29 nuts 30 yen 31 Internal space 32 Caulking part 33 screw holes 34 core metal 35 encoder 36, 36a, 36b Machining processing device 37 chuck 38 Sleeve 39 cap 41, 41a Spindle 42 Male spline part 43a, 43b, 43c Precision processing tool 44 Cylindrical part 45 Cylindrical surface 46 Blocking member 47 Tube 48 Bottom plate 49 Picking part 50 Small diameter cylindrical part 51 Large diameter cylindrical part 52 steps 53 Small diameter step 54 cover 55 volts

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3J017 AA02 BA10 DA01 DB08                 3J058 AA48 AA53 AA62 BA21 BA23                       CB14 CB26 DD02 FA01                 3J101 AA03 AA32 AA43 AA54 AA62                       AA72 BA53 BA56 DA20 FA01                       FA44 GA03

Claims (4)

[Claims] 1. A bearing unit for a wheel for rotatably supporting a wheel and a braking rotating body with respect to a suspension device, comprising an outer ring, a hub, and a plurality of rolling elements, of which the outer ring. Has a double-row outer ring raceway on its inner peripheral surface and does not rotate while being supported by the suspension device at the time of use.The hub is composed of a hub body and an inner ring. A rotary side flange formed on the outer end of the outer peripheral surface and having one axial surface thereof as a mounting surface for supporting the braking rotating body, and a first directly formed on the axial intermediate portion of the outer peripheral surface. Inner ring raceway and a small-diameter step portion formed on the axially inner end portion of the outer peripheral surface, and the inner ring has a second inner ring raceway formed on the outer peripheral surface thereof, and the small-diameter step portion has an outer surface. It is fixed to the hub body in a fitted state, and each rolling element is In a wheel bearing unit rotatably provided in plural numbers between a ring raceway and the first and second inner ring raceways, the rotary side flange has shafts at a plurality of circumferential positions. A screw hole penetrating in the direction is provided, and the mounting surface of the rotary side flange is machined into a predetermined shape and size after at least the outer ring, the hub and the plurality of rolling elements are assembled. A bearing unit for wheels, which is characterized by being a thing. 2. The bearing unit for a wheel according to claim 1, wherein each rolling element is a ball. 3. A caulking portion formed by plastically deforming a portion of an inner ring axially inner end portion of the hub body projecting axially inward more than an axial inner end surface of the inner ring radially outward. The bearing unit for a wheel according to any one of claims 1 and 2, which is fixed to the hub body by the above. 4. The method of manufacturing a wheel bearing unit according to claim 1, wherein after the outer ring, the hub and the plurality of rolling elements are assembled, the hub is rotated with respect to the outer ring. At the same time, a method of manufacturing a bearing unit for a wheel, in which a mounting surface of a rotary side flange is machined into a predetermined shape and size by turning.