JP2001194376A - Rolling bearing unit having rotational speed detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling bearing unit of small diameter for a compact car having a structure to reliably detect the rotational speed. SOLUTION: An inner side of a permanent magnet 21 constituting an encoder 19b externally fitting an end of an inner ring 6 is located in the axial direction inward of an inner end face of a caulked portion 34 formed on an inner end of a hub 5a. In this configuration, the distance between a detection unit of a sensor 23 and the inner side of the permanent magnet 21 is reduced to solve the above problem even taking into consideration the prevention of interference of the caulked portion 34 with the sensor 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION A rolling bearing unit with a rotation speed detecting device according to the present invention rotatably supports a wheel of an automobile with respect to a suspension device, and is used for detecting the rotation speed of the wheel.

[0002]

2. Description of the Related Art Rolling bearing units are used to rotatably support the wheels of an automobile with respect to a suspension system.
Further, in order to control an antilock brake system (ABS) or a traction control system (TCS), it is necessary to detect the rotation speed of the wheel. For this reason, by the rolling bearing unit with the rotation speed detection device that incorporates the rotation speed detection device in the rolling bearing unit,
In recent years, it has been widely practiced to rotatably support the wheel with respect to a suspension device and detect the rotation speed of the wheel.

A rolling bearing unit with a rotation speed detecting device used for such a purpose is disclosed in Japanese Patent Application Laid-Open No. 11-2359.
No. 6 discloses a structure as shown in FIGS. First, a rolling bearing unit 1 with a rotation speed detecting device of a first example of a conventional structure shown in FIG. 5 is configured by incorporating a rotation speed detecting device 3 into a rolling bearing unit 2. The rolling bearing unit 2 includes a hub 5 and an inner ring 6 rotatably supported on the inner diameter side of the outer ring 4. A first end for attaching wheels is provided on an outer peripheral surface of an outer end portion of the hub 5 (an end portion which becomes an outer side in a width direction when assembled to a vehicle, a left end portion in each drawing; the same in the entire specification). , And a first inner raceway 8 on the outer peripheral surface of the intermediate portion.
The inner race 6 has a second inner raceway 9 on the outer peripheral surface thereof, is formed near the inner end of the hub 5, and has an outer diameter dimension smaller than that of the portion where the first inner raceway 8 is provided. It is externally fitted to the reduced step portion 10. A first outer raceway 1 facing the first inner raceway 8 is provided on an inner peripheral surface of the outer race 4.
A second flange 13 for supporting the outer race 4 on a suspension device is formed on an outer peripheral surface of a second outer raceway 12 facing the first and second inner raceway 9. A plurality of rolling elements 14 are provided between the first and second inner raceways 8 and 9 and the first and second outer raceways 11 and 12, respectively. The hub 5 and the inner ring 6 are rotatably supported on the side. In a state in which the inner ring 6 is externally fitted to the stepped portion 10, a nut 15 is screwed into a male screw portion formed at the inner end of the hub 5 to hold down the inner ring 6. The separation from the hub 5 is prevented.

The opening of the inner end (right end in FIG. 1) of the outer race 4 is closed by a cover 16. This cover 16
Is a bottomed cylindrical main body 17 formed by injection molding a synthetic resin.
And a fitting tube 18 connected to the opening of the main body 17. The fitting tube 18 is connected to the opening of the main body 17 by molding the base end thereof at the time of injection molding of the main body 17. The cover 16 configured in this manner is
The first half (the left half in FIG. 5) of the fitting tube 18 is
The inner ring of the outer ring 4 is closed by fixing the outer ring 4 to the inner end of the outer ring 4 with an interference fit.

On the other hand, in order to constitute the rotation speed detecting device, an encoder is provided on a portion of the outer peripheral surface of the inner end 6 of the inner ring 6 which is externally fitted and fixed to the inner end of the hub 5 and which is off the second inner raceway 9. 19 is externally fitted and fixed. This encoder 19
Comprises a support ring 20 and a permanent magnet 21. The support ring 20 is formed by bending a magnetic metal plate such as SPCC or the like to have an L-shaped cross section as a whole, and is externally fixed to the inner end of the inner ring 6 by interference fit. The permanent magnet 21 is formed by, for example, attaching rubber mixed with ferrite powder to the inner surface of the annular portion forming the support ring 20 by baking or the like. The permanent magnets 21 are magnetized, for example, in the axial direction (the left-right direction in FIG. 5), and the magnetization directions are alternately changed at equal intervals in the circumferential direction.
Therefore, S poles and N poles are arranged alternately and at equal intervals in the circumferential direction on the inner surface of the encoder 19, which is the part to be detected.

An insertion hole 22 is formed in a part of the main body 17 forming the cover 16 so as to face the inner surface of the permanent magnet 21 forming the encoder 19.
Are formed in the axial direction of the outer race 1 so as to penetrate. Into the insertion hole 22, a sensor 23 (including a sensor unit in which a detection element and the like are embedded in a synthetic resin. The same applies to the entire specification) is inserted. The sensor 23 includes a Hall element, a magnetoresistive element (MR element)
And an IC incorporating a magnetic detecting element for changing the characteristics in accordance with the flow direction of the magnetic flux, and a waveform shaping circuit for adjusting the output waveform of the magnetic detecting element, and an output from the permanent magnet 21 (or from the permanent magnet 21). And a pole piece made of a magnetic material for guiding a magnetic flux to the magnetic detection element.

[0007] Such a sensor 23 is provided near the tip (left end in FIG. 5), and has a columnar insertion portion 24 through which the insertion hole 22 can be inserted without looseness, and a base end of the insertion portion 24. And an outward flange-shaped flange portion 25 formed at a portion (right end in FIG. 5). A locking groove is formed in the outer peripheral surface of the intermediate portion of the insertion portion 24, and an O-ring 26 is formed in the locking groove.
Is locked.

On the other hand, a part of the outer surface of the cover 16 (the side opposite to the space 27 in which the rolling elements 14 and 14 are to be closed by the cover 16 and the right side in FIG. A locking cylinder 28 is provided around the opening. The sensor 23 connects the insertion portion 24 to the locking cylinder 2.
8, the flange 25 is brought into contact with the distal end surface of the locking cylinder 28, and is coupled to and supported by the locking cylinder 28 by a locking spring 29. It should be noted that such a coupling support structure using the locking spring 29 is described in Japanese Patent Application Laid-Open No. H11-23596.
Since it is described in detail in the official gazette and is not related to the gist of the present invention, detailed illustration and description are omitted.

When the above-described rolling bearing unit with a rotation speed detecting device is used, the second flange 13 fixed to the outer peripheral surface of the outer ring 4 is fixedly connected to the suspension device by bolts (not shown). By fixing the wheel to a first flange 7 fixed to the outer peripheral surface of the hub 5 by a stud 30 provided on the first flange 7, the wheel is rotatably supported with respect to the suspension device. . When the wheel rotates in this state, the vicinity of the end face of the detection unit of the sensor 23 is changed to the N pole existing on the inner surface of the permanent magnet 21 and the S pole.
The poles pass alternately. As a result, the direction of the magnetic flux flowing in the sensor 23 changes, and the output of the sensor 23 changes. The frequency at which the output of the sensor 23 changes in this way is proportional to the rotation speed of the wheel. Therefore, if the output of the sensor 23 is sent to a controller (not shown), ABS and T
CS can be controlled appropriately.

Further, as shown in FIG.
In the case of the second example of the conventional structure described in Japanese Patent Publication No. 96,
A cylindrical portion 31 is formed at the inner end of the hub 5a.
A caulking portion 34 is formed by caulking and expanding a portion protruding from the inner end surface of the inner ring 6 at the tip end of the inner ring 6 outward in the diameter direction,
The inner ring 6 is fixedly connected to the hub 5a by the caulking portion 34. If such a structure is adopted, as compared with the structure in which the inner ring 6 is connected and fixed to the hub 5 by the nut 15 as in the first example of the conventional structure shown in FIG.
Cost reduction can be achieved by reducing the number of parts and the labor for assembling. In the case of the second example of the conventional structure shown in FIG. 6, the structure of the portion where the sensor 23a is connected and supported by the locking cylinder 29 provided on the main body 17 of the cover 16 by the locking spring 29a is the first structure described above. It is different from the example. However, such a coupling support structure using the locking spring 29a is also disclosed in
Since it is described in detail in Japanese Patent Application Laid-Open No. 1-2596 and is not related to the gist of the present invention, detailed illustration and description are omitted. In the case of the structure of the second example, the encoder 19a is also different from the case of the first example.
That is, the encoder 19a of this example is formed by bending a magnetic metal plate such as a mild steel plate so that the cross-sectional shape is
It has an L-shape having two and is formed in an annular shape as a whole. A plurality of through holes 33 are radially formed in the annular portion 32, and the magnetic characteristics of the annular portion 32 are changed alternately at regular intervals in the circumferential direction. In accordance with this, the internal structure of the sensor 23a is also different from that of the first example described above.

[0011]

In the case of the second example of the conventional structure shown in FIG. 6, the cost can be reduced by reducing the number of parts and the labor for assembling. However, the following points still remain. It is desired to improve. That is, as long as the installation space for the encoder 19a (or 19) is sufficiently secured in a relatively large rolling bearing unit for an automobile such as a normal passenger car, there is no particular problem, but the rolling bearing unit is assembled into a small automobile such as a light automobile. In the case of a rolling bearing unit, it is difficult to secure the installation space. The caulking portion 34 formed at the inner end of the hub 5a and the sensor 23a
(Or 23). Then, in the case of interference, the detection unit of the sensor 23a (or 23) cannot be brought close to the detected portion of the encoder 19a (or 19).

In order to ensure the reliability of the rotation speed detection,
The distance between the detection unit of the sensor 23a (or 23) and the detection unit of the encoder 19a (or 19) is set to 0.1 to
It is necessary to be about 2.0 mm, and as described above, it is not preferable that the distance between the detection unit and the detected portion cannot be shortened due to the interference between the caulked portion 34 and the sensor 23a (or 23). The rolling bearing unit with a rotation speed detecting device of the present invention has been invented in view of such circumstances.

[0013]

A rolling bearing unit with a rotation speed detecting device according to the present invention comprises a rolling bearing unit and a rotation speed detecting device similar to the above-described conventional rolling bearing unit with a rotation speed detecting device. Combined with a device. The rolling bearing unit includes a hub, an inner ring, an outer ring, and a plurality of rolling elements. Of these, the hub has a first flange for mounting wheels on the outer peripheral surface of the outer end portion, and a first inner raceway on the outer peripheral surface of the intermediate portion. Further, the inner race has a second inner raceway formed on the outer peripheral surface, and has an outer diameter smaller than that of the portion provided with the first inner raceway provided at the inner end of the hub. Externally fitted to the step. Further, the outer race supports a first outer raceway facing the first inner raceway on the inner circumferential surface and a second outer raceway facing the second inner raceway on the outer circumferential surface by a suspension device. Are formed respectively. In addition, a plurality of rolling elements are provided between the first and second inner raceways and the first and second outer raceways so as to be freely rolled. And, by the caulking portion formed by caulking and expanding the cylindrical portion formed at the portion protruding inward in the axial direction from the inner ring at least at the inner end of the hub at the inner end portion outside the stepped portion, radially outward. The inner ring externally fitted to the step is pressed down toward the step surface of the step, and the inner ring externally fitted to the step is fixedly connected to the hub. On the other hand, the rotation speed detection device includes an encoder and a sensor. Among them, the encoder has a ring-shaped detected portion in which the magnetic properties of the inner surface in the circumferential direction are alternately and equally changed at equal intervals, and deviates from the second inner raceway on the outer circumferential surface of the inner race. Is fixed concentrically with the inner ring. Further, the sensor has a detection unit, and the detection unit is supported by the outer ring or the suspension device in a state where the detection unit is opposed to the inner surface of the detected unit, and the detection unit responds to a change in magnetic characteristics of the detected unit. To change the output signal. In particular, in the rolling bearing unit with the rotation speed detecting device of the present invention, the inner surface of the detected portion projects axially inward from the inner end surface of the caulked portion.

[0014]

With the rolling bearing unit with the rotation speed detecting device of the present invention configured as described above, the wheel is rotatably supported on the suspension device, and the operation of detecting the rotation speed of the wheel is performed by the conventional structure described above. Is the same as In particular, in the case of the rolling bearing unit with the rotation speed detecting device of the present invention, since the inner surface of the ring-shaped detected portion provided on the encoder protrudes inward from the caulked portion, the detected portion and the sensor This sensor and the caulking unit do not interfere with each other even when the detecting unit is brought close to the detecting unit. Therefore, the distance between the detection unit of the sensor and the inner surface of the encoder, which is the detection target, can be shortened, and the reliability of rotation speed detection can be ensured.

[0015]

FIG. 1 shows a first embodiment of the present invention. In addition, the feature of this example is
Even when the rotational speed detecting device is incorporated in a relatively small diameter rolling bearing unit, the distance between the detected portion of the encoder constituting the rotational speed detecting device and the detecting portion of the sensor can be sufficiently reduced, and the sensor The structure is to ensure sufficient output of Since the structure and operation of the other parts are the same as those of the second example of the conventional structure shown in FIG. 6 described above, the same parts are denoted by the same reference numerals, and redundant description will be omitted. The following description focuses on the characteristic portions and the portions different from the second example of the conventional structure.

The inner ring 6 is externally fitted to a step portion 10 formed near the inner end of the hub 5a, and its inner end surface is suppressed by a caulking portion 34 formed at the inner end of the hub 5a. Is fixedly attached. The encoder 19b is supported by a shoulder 35 of the inner race 6, which is a part of the inner race 6 that is off the second inner raceway 9 at the inner end. In the case of the present example, the encoder 19b includes a support ring 20a having a T-shaped cross section and an entire ring shape, and a support ring 20a.
The ring-shaped permanent magnet 21 is attached to the inner surface (the right side surface in FIG. 1) of the annular portion 32a constituting the portion a.

The support ring 20a is formed by bending a magnetic metal plate such as a mild steel plate such as SPCC. The support ring 20a has a cylindrical portion 31a and a 90 ° radially outward direction from the inner end of the cylindrical portion 31a. The connecting ring portion 36 is bent, and the ring portion 32a is bent 180 degrees inward in the radial direction from the outer peripheral edge of the connecting ring portion 36. The width W of the ring portion 32a in the radial direction of the support ring 20a.
_32a is sufficiently larger than the width W ₃₆ of the connecting annular portion ₃₆ (W _32a »W 36). Therefore, the leading edge (inner peripheral edge) of the circular ring portion 32a exists on the inner diameter side of the inner peripheral surface of the cylindrical portion 31a. The permanent magnet 21 is attached to the inner surface of the annular portion 32a constituting the support ring 20a over substantially the entire width of the annular portion 32a over the entire circumference.

The support ring 20a and the permanent magnet 2 as described above
And the encoder 19b comprises the cylindrical portion 3
The base end (outer end) of the inner ring 1a is supported and fixed to the inner end of the inner ring 6 by fitting the outer end to the shoulder 35 of the inner ring 6 by interference fit. In the illustrated, the inner diameter R _32a of the circular ring portions 32a and the permanent magnet 21 is made smaller (R _32a <D ₃₄₎ than the outer diameter D ₃₄ of the crimping portion 34. And
The annular portion 32a and the permanent magnet 21 are positioned axially inward (rightward in the drawing) of the caulking portion 34, and the annular portion 32a and the caulking portion 34 are separated from each other. Accordingly, in this state, the inner peripheral edges of the annular portion 32a and the permanent magnet 21 are located diametrically inner than the outer peripheral edges of the caulked portion 34. In this manner, the ring portion 32a
The reason why the inner peripheral edge of the permanent magnet 21 is positioned diametrically inward of the outer peripheral edge of the caulking portion 34 in addition to separating the caulking portion 34 and the caulking portion 34 is to secure (increase) the output of the sensor 23 described later. That's why.

As described above, the encoder 19b is connected to the inner ring 6
The outer surface of the permanent magnet 21 is positioned axially inward from the inner end surface of the caulked portion 34 by a predetermined amount δ ₁ that is designed, in a state where the permanent magnet 21 is externally fitted and fixed to the shoulder portion 35. I have. For this reason, in the illustrated example, the inner surface of the permanent magnet 21 is positioned axially inward by δ ₂ from the inner end surface of the outer ring 4. That is, when the encoder 19b is pressed toward the inner ring 6 by a press-fitting jig (not shown) so that the base end of the cylindrical portion 31a is fitted to the shoulder 35, the inner end surface of the outer ring 4 is fixed to the permanent The reference surface is used for positioning the inner surface of the magnet 21. Therefore, even when the annular portion 32a and the caulking portion 34 are separated from each other as in the example shown in the drawing, the permanent magnet 21 which is the portion to be detected can be used.
Can be positioned in the axial direction of the inner side surface of the member.

The permanent magnet 2 of the encoder 19b as described above
1 has a tip end surface of the sensor 23 (the left end surface in FIG. 1).
Are opposed to each other through a minute gap 37. The thickness of the minute gap 37 is 0.1 to
It is about 2.0 mm (generally 0.5 to 1.0 mm).
The sensor 23 is connected to the outer race 4 via the cover 16.
The support structure is the same as that of the first example of the conventional structure shown in FIG. 5 described above.

As described above, in the case of the rolling bearing unit with the rotation speed detecting device according to the present invention, the inner surface of the permanent magnet 21 which is the ring-shaped detected portion constituting the encoder 19b is formed by the caulking portion. It protrudes inward in the axial direction from 34. Therefore, even if the inner surface of the permanent magnet 21 and the detecting portion of the sensor 23 are brought close to each other, the sensor 23 and the caulking portion 34 do not interfere. Therefore, the distance between the detecting portion of the sensor 23 and the inner side surface of the permanent magnet 21 can be shortened, and the reliability of the rotation speed detection can be secured.

In the illustrated example, the encoder 19
Since the ring portion 32a of the support ring 20a constituting the b is separated from the caulking portion 34, and the inner peripheral edge of the permanent magnet 21 is positioned diametrically inward from the outer peripheral edge of the caulking portion 34. The output of the sensor 23 can be secured (increased). This point will be described with reference to FIG.

In order to increase the magnetic flux density existing around the permanent magnet 21, it is preferable that the support ring 20a is made of a magnetic material. On the other hand, the hub 5a is generally made of carbon steel which is a magnetic material. Therefore, FIG.
As shown in (B), the ring portion 32a and the caulked portion 3
4 is brought into contact with the inner surface of the permanent magnet 21, the magnetic flux coming out of the inner surface of the permanent magnet 21 is strongly drawn by the caulking portion 34.
As shown by the arrow in (B), the minimum distance required for the magnetic flux density (hereinafter, referred to as detectable magnetic flux) required for detection by the sensor 23 is reduced. In other words, the reachable distance L of the detectable magnetic flux from the inner surface of the permanent magnet 21
₁ becomes shorter. On the other hand, when the annular portion 32a and the caulking portion 34 are separated from each other as in the structure of the present embodiment, the magnetic flux emitted from the inner side surface of the permanent magnet 21 causes the caulking portion 3
4 does not flow much, and the reachable distance of the detectable magnetic flux increases as indicated by the arrow in FIG. In other words, reach L ₂ of the detectable magnetic flux from the inner surface of the permanent magnet 21 becomes longer. As a result, the permanent magnet 2
Even if the distance between the inner surface of the sensor 1 and the detection unit of the sensor 23 is increased, the output of the sensor 23 can be sufficiently ensured. In this manner, the ring portion 32a and the caulked portion 3
It was confirmed by experiments conducted by the inventor that the distance between the inner surface of the permanent magnet 21 and the detecting portion of the sensor 23 can be increased by separating the sensor 4 from the inner surface of the permanent magnet 21.

In the case of this embodiment, the output of the sensor 23 is also ensured by locating the inner peripheral edge of the permanent magnet 21 radially inward of the outer peripheral edge of the caulking portion 34. . That is, by adopting such a configuration,
By increasing the width W ₂₁ regarding the diameter direction of the permanent magnet 21, and increasing the reach of the detectable magnetic flux from the inner surface of the permanent magnet 21. At the same time, the output of the sensor 23 is secured by increasing the magnetic flux density.

FIG. 3 shows a second embodiment of the present invention.
An example is shown. In the case of this example, the sensor 23b is supported and fixed to a knuckle 38 constituting a suspension device.
The detection unit provided on the outer surface of the distal end of the sensor 23b is opposed to the inner surface of the permanent magnet 21 constituting the encoder 19b via a minute gap 37a. Also in the case of this example, the inner side surface of the permanent magnet 21 is located axially inward of the inner end of the caulked portion 34 formed at the inner end of the hub 5a. Therefore, although the inner peripheral edge of the encoder 19b exists on the inner diameter side of the outer peripheral edge of the caulked portion 34, the caulked portion 34 does not interfere with the sensor 23b. In the case of this example, the encoder 19
The combination seal ring is constituted by the support ring 20a constituting b and the seal ring 39 which is fitted and supported on the inner end of the outer race 4. That is, in the case of this example, the support ring 20a also has a function as a slinger. Other configurations and operations are the same as those of the above-described first example, and thus redundant description will be omitted.

FIG. 4 shows a third embodiment of the present invention.
An example is shown. In the case of this example, the opening at the inner end of the outer race 4 is closed with a cover 16a made of a metal plate.
The sensor 23c is supported and fixed to a part of the through hole 40 formed in a part of the part a, which faces the inner side surface of the permanent magnet 21 constituting the encoder 19b. That is, this sensor 20c
In order to constitute the above, a synthetic resin for embedding and supporting the Hall IC and the like is molded into the through hole 40 of the cover 16a. A connector 41 for connecting a plug provided at an end of a signal transmission harness is provided on the sensor 23c. Also in the case of this example, the inner surface of the permanent magnet 21, which is the detected portion of the encoder 19b, protrudes inward in the axial direction from the inner end surface of the caulking portion 34 formed at the inner end of the hub 5a. So, this caulking part 34
And the sensor 23c do not interfere with each other. Other configurations and operations are the same as in the case of the above-described first example.

In each of the examples shown in the drawings, as the encoder 19b, the annular permanent magnet 2 is attached to the annular portion 32a of the support ring 20a.
1 is attached. However, the embodiment of the present invention is not limited to the encoder 19b having such a permanent magnet 21, but an encoder having no permanent magnet as in the second example of the conventional structure shown in FIG. Can also be used. Also, in each example shown in the figure, in order to increase the magnetic flux density at the detecting portion of the sensor, the inner peripheral edge of the permanent magnet constituting the encoder is diametrically larger than the outer peripheral edge of the caulking portion formed at the inner end of the hub. Although shown in the case where the width in the diametrical direction of the permanent magnet is increased by being positioned inward, the inner peripheral edge of the permanent magnet is larger in diameter than the outer peripheral edge of the caulked portion if the detection capability of the sensor has a margin. It is also possible to position it outside the direction.

[0028]

Since the present invention is constructed and operates as described above, it is possible to assemble a rotational speed detecting device having excellent detecting performance even with a relatively small diameter rolling bearing unit. For this reason, it is possible to realize a small-sized rolling bearing unit with a rotation speed detecting device, which is incorporated in a small vehicle such as a mini vehicle and has excellent handling properties.

[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 cross-sectional view corresponding to the portion A in FIG. 1 for explaining the effect of separating the encoder and the caulking portion.

FIG. 3 is a sectional view showing a second example of the embodiment of the present invention.

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

FIG. 5 is a sectional view showing a first example of a conventional structure.

FIG. 6 is a partial sectional view showing the second example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rolling bearing unit with rotation speed detection device 2 Rolling bearing unit 3 Rotation speed detection device 4 Outer ring 5, 5a hub 6 Inner ring 7 First flange 8 First inner ring raceway 9 Second inner raceway 10 Step 11 Outer ring raceway 12 Second outer ring raceway 13 Second flange 14 Rolling element 15 Nut 16, 16a Cover 17 Main body 18 Fitting cylinder 19, 19a, 19b Encoder 20, 20a Support ring 21 Permanent magnet 22 Insertion hole 23, 23a, 23b , 23c Sensor 24 Insertion part 25 Flange part 26 O-ring 27 Space 28 Locking cylinder 29, 29a Locking spring 30 Stud 31, 31a Cylindrical part 32, 32a Ring part 33 Through hole 34 Caulking part 35 Shoulder part 36 Connecting circle Ring part 37, 37a Micro gap 38 Knuckle 39 Seal ring 40 Through hole 41 Connector

Claims (1)

[Claims] 1. A hub provided with a first flange for mounting a wheel on the outer peripheral surface of the outer end, a first inner raceway on the outer peripheral surface of the intermediate portion, and a second inner raceway on the outer peripheral surface. Then, an inner ring provided at the inner end of the hub and having an outer diameter dimension smaller than that of the portion provided with the first inner ring raceway is externally fitted to the stepped portion. An outer ring formed with a first outer ring track facing the inner ring track and a second outer ring track facing the second inner ring track, a second flange formed on the outer peripheral surface for supporting the suspension, A first and a second inner raceway and the first and the second outer raceway, between each, a plurality of rolling elements provided to be freely rolled,
At the inner end of the hub, at least the stepped portion formed by caulking and expanding a cylindrical portion formed at a portion protruding inward in the axial direction beyond the inner ring fitted at least to the stepped portion outward in the diameter direction. An inner ring that is fitted to the outer surface of the step is pressed toward the step surface of the step, and the inner ring that is fitted to the step is fixedly connected to the hub. An encoder fixed to the portion of the outer peripheral surface of the inner ring that deviates from the second inner ring raceway, the encoder being concentrically fixed to the inner ring, having a toroidal detection portion having characteristics changed alternately and at equal intervals. A detection unit that is supported by the outer ring or the suspension device in a state where the detection unit faces the inner surface of the detection target, and changes an output signal in response to a change in magnetic characteristics of the detection target; And a rotation speed detecting device having a sensor for causing In a rolling bearing unit with a rotation speed detecting device, the inner surface of the detected portion is projected more inward in the axial direction than the inner end surface of the caulking portion. Rolling bearing unit.