JP2002061660A - Rolling bearing unit for wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively reduce a weight and realize an inexpensive structure. SOLUTION: An inner ring 5 is fixed to an inner end part of a hub 4a for supporting a non-driving wheel, by means of a caulking part 19. A through hole 8 is formed on a central part of the hub 4a in a state of axially penetrating through the hub 4a. A part between an outer end part of an outer ring 1 and an outer peripheral face of an intermediate part of the hub 4a is closed by a seal ring 13, and a part between an inner end part of the outer ring 1 and the inner ring 5 is closed by a combined seal ring 26. According to this structure, the components can be effectively used in common with a structure for supporting a driving wheel to achieve the subject of this invention.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION A rolling bearing unit for a wheel according to the present invention includes a rear wheel of a non-drive wheel FF vehicle (front engine front wheel drive vehicle) supported by an independent suspension type suspension of an automobile and an FR vehicle (front). Engine rear wheel drive) and R
The front wheel の of the R-vehicle (rear engine rear-wheel drive vehicle) is used to rotatably support the suspension system.

[0002]

2. Description of the Related Art For a wheel in which an outer wheel and a hub are rotatably combined via a rolling element in order to rotatably support a non-drive wheel supported by an independent suspension type suspension of an automobile with respect to a suspension device. Various types of rolling bearing units are used. In such a rolling bearing unit for wheels,
The outer race has a first mounting flange for supporting the suspension on the outer peripheral surface and an outer raceway on the inner peripheral surface, and does not rotate during use. Further, the hub is a second portion for fixing the non-driving wheels to a portion near the outer end of the outer peripheral surface (the outside is a side which is outside in the width direction of the vehicle when attached to the vehicle. The same applies hereinafter). The inner flange also has an inner raceway directly or via an inner race at the intermediate portion, and rotates during use. The non-drive wheels fixed to the hub are rotated with respect to the suspension device to which the outer ring is fixed by providing the plurality of rolling elements so as to freely roll between the outer ring track and the inner ring track. Support freely. In the case of a rolling bearing unit for a wheel for supporting a non-driving wheel as described above, generally, the hub does not need a through-hole penetrating the center portion, and thus the hub is made solid.

[0003] On the other hand, the driving wheel 前 front wheel of the FF vehicle, F
In the case of a wheel rolling bearing unit used to rotatably support the rear wheel of an R vehicle and an RR vehicle, and all wheels of a 4WD vehicle (four-wheel drive vehicle) with respect to a suspension, a constant velocity joint It is necessary to connect the shaft with a hub for fixing the wheels, and therefore, the hub is generally provided with a through hole for inserting the shaft.

A rolling bearing unit for a wheel for supporting a non-driving wheel as shown in FIG. 3 has conventionally been considered and actually used. This structure is intended to make the components of the rolling bearing unit for wheels common for the driving wheels and the non-driving wheels. In an assembled state to a vehicle, the outer ring 1 that does not rotate while being supported by the suspension device has a first mounting flange 2 for supporting the suspension device on the outer peripheral surface, and a double-row outer ring raceway 3 on the inner peripheral surface. 3 respectively. Inside the outer ring 1, a hollow cylindrical hub 4 and an inner ring 5, each of which rotates during use, are arranged. Of these, the hub 4 has a second mounting flange 6 for fixing a non-driving wheel at the outer end (left end in FIG. 3) of the outer peripheral surface, and a first inner raceway 7a at the intermediate portion, respectively. At the same time, a through hole 8 penetrating in the axial direction is formed at the center. The inner race 5 has a second inner raceway 7b formed on an outer peripheral surface thereof, and an inner end portion of the hub 4 (inside means a side near a center in a width direction of the vehicle when mounted on the vehicle, Right of each figure; the same applies hereinafter.) Externally fitted to the outer peripheral surface.

A bolt 9 is inserted into the through hole 8, and a nut 10 is screwed into a portion of the bolt 9 protruding from the outer end surface of the hub 4 at the tip end, and further tightened. The head 11 and the nut 1 of these bolts 9
0, the hub 4 and the inner ring 5 are sandwiched, and the hub 4 and the inner ring 5 are integrally connected. A plurality of rolling elements 12, 12 (balls) are provided between the outer raceways 3, 3 and the inner raceways 7a, 7b so as to roll freely. In addition, a bottomed short cylindrical cover 14 formed by bending a metal plate is attached to the inner end opening of the outer ring 1. At the same time, the outer end opening of the outer race 1 and the hub 4
A seal ring 13 is provided between the outer peripheral surface and the intermediate portion. This prevents foreign substances such as muddy water and dust from entering the space 15 where the plurality of rolling elements 12 and 12 are installed, and the grease for lubrication existing in the space 15 is externally provided. It prevents leakage.

When the rolling bearing unit for a wheel configured as described above is used, the first mounting flange 2 provided on the outer race 1 is fixed to a part of a suspension device (not shown) and the second mounting flange provided on the hub 4. A non-drive wheel (not shown) is fixed to the mounting flange 6. In the case of the wheel rolling bearing unit for supporting the non-driving wheels shown in FIG. 3, the hub is provided between the wheel rolling bearing unit for supporting the driving wheels as described above. Common use can be achieved. That is, in the case of a general wheel rolling bearing unit for supporting the drive wheels, as described above, a through hole (generally, a spline) for inserting the shaft of the constant velocity joint into the center of the hub is used. Holes). On the other hand, in the case of the structure shown in FIG. 3, since the through hole 8 is provided in the center of the hub 4, it is not necessary to separately manufacture the hub depending on the presence or absence of the through hole 8. In addition, the through-hole 8 of the hub 4 for the non-drive wheel is kept in a state before forming the spline, thereby suppressing an increase in cost due to the formation of the spline.

In the case of the structure shown in FIG. 3, since the inner end opening of the through hole 8 is tightly closed by the bolt 9 and the nut 10, the grease existing in the space 15 is reduced. There is no entry into this through hole 8. Therefore, it is not necessary to increase the amount of the grease in consideration of the loss to the through hole 8.

Further, US Pat. No. 3,589,747 discloses a rolling bearing unit for a wheel as shown in FIG. In the case of the rolling bearing unit for a wheel, a hollow cylindrical hub 4 and an inner ring 5 which is externally fitted and fixed to an inner end (right end in FIG. 4) of the hub 4 are provided inside the outer ring 1 with respect to the outer ring 1. And are rotatably supported by tapered roller bearings. For this reason, a pair of outer ring raceways 1 each having a conical concave shape are formed on the inner circumferential surfaces of both axial portions of the outer ring 1.
6 and 16 are formed with the inclination directions reversed.
Also, on the outer peripheral surface of the intermediate portion of the hub 4 and the outer peripheral surface of the inner ring 5,
Inner ring raceways 17a, 17b each having a conical convex shape
Are formed with the inclination directions opposite to each other. And
The outer raceways 16, 16 and the inner raceways 17a, 17b
, A plurality of tapered rollers 18 are provided so as to roll freely. In order to fix the inner ring 5 to the inner end of the hub 4, in the case of the structure shown in the drawing, a caulking portion 19 is formed at the inner end of the hub 4 so as to project outward in the diameter direction. I have. Then, between the caulked portion 19 and the step portion 20 formed on the outer peripheral surface of the intermediate portion of the hub 4, the inner ring 5
Is sandwiched.

A short cylindrical cover 14 with a bottom formed by bending a metal plate is attached to the inner end opening of the outer ring 1. At the same time, a seal ring 13 is provided between an outer end (left end in FIG. 4) opening of the outer race 1 and an outer peripheral surface of an intermediate portion of the hub 4. Also, at the center of the hub 4,
A through hole 8 penetrating in the axial direction is formed, and a sealing plate 21 is fixed to the inner peripheral surface of the inner end of the through hole 8, and the inner end of the through hole 8 is closed tightly by the sealing plate 21. I have.

US Pat. No. 3,589,397, constructed as described above.
In the case of the structure described in the specification of Japanese Patent No. 747, unlike the structure shown in FIG. 3, a member such as a bolt 9 (see FIG. 3) is not inserted into the inside of the through hole 8 formed in the hub 4. I'm done. Moreover, since the sealing plate 21 is provided at the inner end of the through hole 8, grease existing in the space 15 in which the plurality of tapered rollers 18, 18 are installed enters the through hole 8. The grease does not need to be increased.

[0011]

In recent years, there has been a strong demand for reducing the weight of rolling bearing units for wheels from the viewpoint of improving fuel efficiency, riding comfort, and power performance of automobiles. As a means for reducing the weight of such a rolling bearing unit for a wheel, it is effective to remove a portion of the hub of the rolling bearing unit for a wheel for supporting a non-drive wheel that is unnecessary in structure. . For this purpose, a through-hole should be formed in the hub not only in the case of a wheel rolling bearing unit for supporting driving wheels, but also in the case of a wheel rolling bearing unit for supporting non-driving wheels. It is desirable to reduce the weight of an automobile.

On the other hand, a structure in which the hub 4 is substantially hollowed out by providing the through hole 8 in the hub 4 as in the structure shown in FIG. 3 has been conventionally considered. This is merely provided from the viewpoint of commonality. Therefore, in the case of the structure shown in the figure, a part of the bolt 9 is inserted into the through hole 8 and effective weight reduction cannot be achieved. On the other hand, US Pat.
In the case of the structure described in the specification of Japanese Patent No. 89,747, the hub 4 is provided with the through hole 8, and a heavy member such as a bolt is not inserted into the through hole 8. Therefore, FIG.
In the case of the structure shown in FIG. 7, unlike the structure shown in FIG. 3, the weight can be effectively reduced.

However, the structure shown in FIG. 4 is intended only to reduce the weight of the rolling bearing unit for supporting the non-driving wheels, and the rolling bearing unit for supporting the non-driving wheels and the driving wheel support are provided. It is not intended to share as many parts as possible with the rolling bearing unit for use in order to reduce costs. For example, when the structure shown in FIG. 4 is diverted for driving wheel support, not only the sealing plate 21 is removed but also the cover 14 is replaced in order to insert the constant velocity joint shaft into the center of the hub. Needs to be provided. As described above, exchanging parts in order to change from non-drive wheel use to drive wheel use causes an increase in cost due to an increase in labor for manufacturing parts and managing parts.

In the case of the structure shown in FIG. 4, the grease filled in the space in which the tapered rollers 18, 18 are installed also enters the space between the cover 14 and the sealing plate 21, and the taper is formed. There is a possibility that the grease existing in the space where the rollers 18, 18 are installed is reduced. For this reason, it is necessary to increase the filling amount of grease into this space, and the cost reduction effect by reducing the filling amount of grease is insufficient. The rolling bearing unit with a rotation speed detection device of the present invention is designed in consideration of the above-described circumstances.
The present invention was invented to realize a structure capable of effectively reducing the weight of a wheel rolling bearing unit for supporting a wheel that is a non-drive wheel at low cost.

[0015]

A rolling bearing unit with a rotation speed detecting device according to the present invention has a first mounting flange for supporting the suspension on an outer peripheral surface, a double row outer raceway on an inner peripheral surface, Each has an outer ring that does not rotate even during use, and a second mounting flange for supporting a non-drive wheel at a portion near one end of the outer peripheral surface, and a first inner ring raceway also at the intermediate portion directly or via the inner ring. A hub that rotates at the time of use, and a second inner raceway on its outer peripheral surface, and has the other end of the hub radially outwardly. An inner ring fixed to the hub by a caulking portion formed by plastic deformation, and a plurality of rolling elements rotatably provided between the outer ring tracks and the first and second inner ring tracks. And Further, an annular first contact-type seal is provided between one end opening of the outer ring and the outer peripheral surface of the intermediate portion of the hub, between the other end opening of the outer ring and the outer peripheral surface of the end of the inner ring. An annular second contact-type seal is provided for each.

[0016]

In the case of the wheel rolling bearing unit of the present invention constructed as described above, a through hole is provided at the center of the hub so as to communicate both end faces of the hub, and a caulking formed at the end of the hub. The inner ring is fixed to the hub by a portion. For this reason, it is possible to reduce the weight of the hub by removing unnecessary portions from the structural point of the hub. Further, in the case of the present invention, the first and second sealing members can prevent grease existing for lubrication in the space in which the rolling elements are installed from flowing out of this space, and the amount of this grease can be reduced. Does not need to be increased. Therefore, the amount of grease does not increase, and the weight and cost do not increase with the provision of the through hole. Further, the first and second sealing members can be used as they are even when the wheel rolling bearing unit is diverted for driving wheel support. For this reason, the parts can be shared in a high degree, and the cost can be further reduced.

[0017]

FIG. 1 shows a first embodiment of the present invention. The feature of the present invention is to effectively reduce the weight of a rolling bearing unit for a wheel for supporting a wheel that is a non-driving wheel, to reduce the amount of grease used, and to use a wheel for supporting a driving wheel. In order to realize an inexpensive structure by sharing parts between the rolling bearing unit and the rolling bearing unit, unnecessary portions in the structure of the hub 4a are lightened and a sealing structure is devised. . The structure of the portion for rotatably supporting the non-drive wheels fixed to the hub 4a with respect to the suspension device is the same as the conventional structure shown in FIGS. In addition, description of overlapping parts will be omitted or simplified, and the following description will focus on the characteristic parts of the present invention.

A rolling bearing unit for a wheel according to the present invention has a hub for fixing a non-driving wheel through a plurality of rolling elements 12 inside an outer ring 1 which is fixed to a part of a suspension device during use. 4a is arranged. An annular seal ring 13, which is a first contact type seal, is provided between an outer end (left end in FIG. 1) opening of the outer race 1 and an outer peripheral surface of an intermediate portion of the hub 4a. The seal ring 13 includes a metal core 22 formed of a metal plate such as a steel plate having a substantially U-shaped cross section and a ring shape as a whole, and an elastic material 23 such as an elastomer such as rubber.
It consists of: The cylindrical portion provided on the outer peripheral edge of the cored bar 22 is internally fixed to the inner peripheral surface of the outer end of the outer ring 1 by interference fitting. And the elastic material 23
Of the plurality of seal lips are slidably contacted with the inner surface of the base end of the second mounting flange 6 provided on the outer peripheral surface of the outer end of the hub 4a and the outer peripheral surface of the intermediate portion of the hub 4a. Let me. Therefore, the seal ring 13 seals the outer end opening of the space 15 in which the rolling elements 12 and 12 are installed over the entire circumference.

On the other hand, a through hole 8 is formed at the center of the hub 4a so as to penetrate the hub 4a in the axial direction. Accordingly, both ends of the through hole 8 are respectively opened at the center of both end surfaces of the hub 4a. It is preferable to increase the inner diameter of the through hole 8 as much as possible within a range that can withstand the load applied to the wheel rolling bearing unit from the viewpoint of reducing the weight. However, in consideration of use for driving wheel support, a cutting allowance for forming a spline groove on the inner peripheral surface is secured.

The hub 4a has an inner end (the right end in FIG. 1).
By forming the step portion 24 in the deviated portion, a portion on the inner end side of the step portion 24 is a small-diameter cylindrical portion 25. The inner ring 5 is externally fitted to the outer peripheral surface of the small-diameter cylindrical portion 25, and a portion of the inner end of the small-diameter cylindrical portion 25 that projects in the axial direction from the inner ring 5 is directed toward the inner end surface of the inner ring 5. By caulking, a caulked portion 19 is formed.
Therefore, the inner ring 5 is sandwiched between the caulking portion 19 and the step portion 24 and is integrally connected to the hub 4a. In the illustrated example, balls are used as the rolling elements 12 and 12. However, in the case of a heavy wheel rolling bearing unit, tapered rollers may be used as the rolling elements.

An annular combination seal ring 26, which is a second contact type seal, is provided between the inner end (right end in FIG. 1) opening of the outer race 1 and the outer peripheral surface of the shoulder of the inner race 5. Provided. The combination seal ring 26 includes a seal ring 27 and a slinger 28. The slinger 28 is formed by forming a metal plate such as a steel plate or a stainless steel plate into an annular shape with an L-shaped cross section.
The cylindrical portion 29 has a circular ring portion 30 that is bent radially outward at a right angle from the inner end portion. Such a slinger 28
Is externally fitted to the inner end of the inner ring 5 by tightly fitting the cylindrical portion 29 to the outer peripheral surface of the shoulder of the inner ring 5.

On the other hand, the seal ring 27 is made of a metal plate such as a steel plate, a stainless steel plate or the like, and has a L-shaped cross section formed into a ring shape as a whole, and a ring portion 32 constituting the core bar 31. And an elastic member 33 such as an elastomer such as rubber, which is supported on the inner side surface of the elastic member. Also, this elastic material 3
Reference numeral 3 has a plurality of (two in the illustrated example) seal lips at the tip. Such a seal ring 27 is provided on the core metal 3.
The cylindrical portion 34 of the outer ring 1 is tightly fitted on the inner peripheral surface of the inner end portion of the outer ring 1 to be fixedly fitted to the inner end portion of the outer ring 1.

Then, the leading edge of the seal lip of the elastic member 33 provided on the seal ring 27 is connected to the slinger 28.
The outer circumferential surface of the cylindrical portion 29 and the outer circumferential surface of the circular ring portion 30 are slid over the entire circumference, so that the inner end opening of the space 15 in which the plurality of rolling elements 12 Sealed all around.

A cover 36 is fixedly fitted to a cylindrical portion 35 formed for centering a wheel constituting a non-driving wheel at the outer end of the hub 4a. The end opening is closed to prevent solid foreign matter such as pebbles from entering the through hole 8. That is, when a solid foreign object such as pebbles enters the through hole 8 when the automobile is running, and the solid foreign object is thrown around by the centrifugal force accompanying the rotation of the non-drive wheel, it may injure a pedestrian or damage the vicinity. There is a possibility of damaging other running cars. Therefore, the cover 36 prevents the solid foreign matter from entering the through hole 8.

On the other hand, in the case of the present embodiment, the inner end opening of the through hole 8 is left open without being closed. Therefore,
Rainwater or the like may enter the through hole 8 from the inner end opening. Therefore, in the case of the present example, a portion of the cover 36 that is fitted and fixed to the cylindrical portion 35 is formed in a comb shape, and gaps 37 and 37 are formed in the fitting portion between the cover 36 and the cylindrical portion 35. Is provided. The liquid such as rainwater or minute dust that has entered the through-hole 8 is centrifugal when traveling, and is gravitational when stopped.
Is discharged through. Therefore, rainwater, dust, and the like do not accumulate in the through hole 8. As described above, since the structure is not always immersed in rainwater, generation and progress of rust do not become a major problem. The cover 36 is formed in such a shape and size that it does not interfere with the axis of the constant velocity joint so that the cover 36 can be used even when used for driving wheels.

In the case of the rolling bearing unit for a wheel of the present invention constructed as described above, a through hole 8 is provided at the center of the hub 4a for communicating both end faces of the hub 4a. The inner ring 5 is fixed to the hub 19 by a caulking portion 19 formed at the end. For this reason, it is possible to reduce the weight of the hub 4a effectively by removing unnecessary portions in the structure.

In the case of the present invention, the seal ring 13 and the combined seal ring 26 seal the openings at both ends of the space 15 in which the rolling elements 12, 12 are installed. Therefore, it is possible to prevent grease existing in the space 15 for lubrication from flowing out of the space 15 and reduce the amount of the grease to the above-mentioned rolling elements 12 and 12.
There is no need for more than is needed to lubricate. Therefore, the amount of grease does not increase, and the weight and cost do not increase with the provision of the through hole 8. Further, the seal ring 13 and the combined seal ring 26 can be used as they are even when the wheel rolling bearing unit is diverted for driving wheel support. For this reason, the parts can be shared in a high degree, and the cost can be further reduced.

Next, FIG. 2 shows a second embodiment of the present invention.
An example is shown. In the case of this example, an encoder 38, which is a permanent magnet made of rubber mixed with powder made of a ferromagnetic material such as ferrite, is coupled to a slinger 28 constituting the combination seal ring 26. The encoder 38 is magnetized in the axial direction, and alternately changes the magnetization direction at regular intervals in the circumferential direction, so that the S pole and the N pole are formed on the inner surface in the circumferential direction. Are arranged alternately and at equal intervals. The encoder 38 is connected and supported on the inner surface of the annular portion 30 of the slinger 28 by bonding, printing, or the like.

Also in the case of the present embodiment, the cover 36a is fitted and fixed inside the cylindrical portion 35 formed at the outer end of the hub 4a, thereby closing the outer end opening of the through hole 8. However, in the case of the present example, no gap is formed in the fitting portion between the cover 36a and the cylindrical portion 35, and the fitting is sealed so as to prevent intrusion of rainwater or the like. At the same time, a sealing plate 39 is fitted and fixed in a portion of the through hole 8 near the opening at the inner end of the intermediate portion. The inner peripheral surface of the portion of the through hole 8 where the sealing plate 39 is internally fitted and fixed is finished by turning, so that no gap is formed between the inner peripheral surface and the outer peripheral edge of the sealing plate 39. It can be fitted freely by interference fit. Therefore, in the case of this example, rainwater or the like does not enter the through hole 8 except for a part of the inner end thereof.

When the present embodiment having the above-described configuration is used, the outer ring 1 is supported and fixed to a knuckle (not shown) constituting a suspension device, and a detection unit provided at the tip of the sensor unit 40 supported by the knuckle. Is opposed to the inner surface of the encoder 38 via a minute gap. The sensor unit 40 includes a Hall element and a magnetoresistive element (M
(R element), etc., a magnetic detecting element for changing characteristics according to the flow direction of magnetic flux, an IC 41 incorporating a waveform shaping circuit for adjusting an output waveform of the magnetic detecting element, and an output from the encoder 38 (or an encoder 38). Flows into)
A pole piece or the like made of a magnetic material for guiding a magnetic flux to the magnetic detection element is embedded in a synthetic resin.

When the hub 4a and the inner wheel 5 rotate together with the non-driving wheels during running of the automobile, the sensor unit 40 detects the rotation of the encoder 38 fixed to the inner wheel 5, and determines the rotation speed of the non-driving wheels. Can do things. As described above, the structure of the present example is based on the combination seal ring 26.
By assembling the encoder 38 with the slinger 28 constituting the above, a structure for supporting the sensor unit 40 on a knuckle and realizing a structure for detecting the rotational speed of the non-driving wheels can be realized. Although the illustrated example does not have a structure in which rainwater accumulates in the caulking portion 19, a hub is used when it is desired to prevent a slight rust of the caulking portion 19 and maintain the holding strength of the inner ring 5 for a longer period. It is also possible to paint around the caulking part 19 of 4a. Other configurations and operations are the same as those in the above-described first example, and therefore, the same parts are denoted by the same reference numerals and overlapping description will be omitted.

[0032]

The rolling bearing unit for a wheel according to the present invention comprises:
Because of the configuration and operation described above, weight reduction can be effectively achieved, and this weight reduction can contribute to improvement of fuel efficiency, ride comfort, and power performance of an automobile. Further, the amount of grease sealed inside can be suppressed to a small level, and parts can be shared in a higher order, so that the cost can be further reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first example of an embodiment of the present invention.

FIG. 2 is a sectional view showing the second example.

FIG. 3 is a sectional view showing a first example of a conventional structure.

FIG. 4 is a sectional view showing the second example.

[Explanation of symbols]

 Reference Signs List 1 outer ring 2 first mounting flange 3 outer ring track 4, 4a hub 5 inner ring 6 second mounting flange 7a first inner ring track 7b second inner ring track 8 through hole 9 bolt 10 nut 11 head 12 rolling element 13 seal Ring 14 Cover 15 Space 16 Outer ring raceway 17a, 17b Inner ring raceway 18 Taper roller 19 Caulking part 20 Stepped part 21 Sealing plate 22 Core metal 23 Elastic material 24 Stepped part 25 Small diameter cylindrical part 26 Combination seal ring 27 Seal ring 28 Slinger 29 Cylindrical part Reference Signs List 30 circular ring part 31 core metal 32 circular ring part 33 elastic material 34 cylindrical part 35 cylindrical part 36, 36a cover 37 gap 38 encoder 39 sealing plate 40 sensor unit 41 IC

Claims (1)

[Claims] 1. An outer ring which has a first mounting flange for supporting the suspension on an outer peripheral surface, a double row of outer raceways on an inner peripheral surface, and which does not rotate during use, and one end of the outer peripheral surface. A second mounting flange to support the non-driving wheel in the part,
Similarly, a hub which has a first inner raceway directly or via an inner race in the intermediate portion, a through hole communicating the both end surfaces in the center portion, and which rotates at the time of use, and a second inner raceway on the outer peripheral surface thereof An inner ring fixed to the hub by a caulking portion formed by plastically deforming the other end of the hub radially outward, the outer ring tracks, the first and second inner ring tracks A plurality of rolling elements rotatably provided between the outer ring and an annular first contact seal between the one end opening of the outer ring and the outer peripheral surface of the intermediate portion of the hub. A rolling bearing unit for a wheel, wherein an annular second contact type seal is provided between the other end opening of the outer ring and the outer peripheral surface of the end of the inner ring.