JPH08178939A - Rolling bearing unit with rotation speed detector - Google Patents

Abstract

(57) [Summary] [Object] To increase the output voltage induced in the sensor 20a as the hub 1 rotates so that the rotation speed can be reliably detected. [Structure] The sensor 20a includes a permanent magnet 22a, a stator 23, and a coil 24. Gear-shaped irregularities are formed on the inner peripheral surface of the permanent magnet 22a, and the inner peripheral surface is opposed to the outer peripheral surface of the small diameter portion 14 of the tone wheel 13 via a minute gap 25. The permanent magnet 2 is formed by a part of the small-diameter portion 14.
A plurality of through holes 17, 17 are provided in a portion facing the inner peripheral surface of 2a.
Are formed at the same pitch as the irregularities and at equal intervals in the circumferential direction. The inner peripheral surface of the inner cylindrical portion 27 and the side surface of the circular ring portion 34 that constitute the stator 23 are the tone wheel 13 and
The outer peripheral surface of the small diameter portion 14 and the side surface of the step portion 16 are opposed to each other via the minute gap 25. As the facing area between the stator 23 and the tone wheel 13 becomes wider and the magnetic resistance between both members 23, 13 becomes lower, the output of the sensor 20a increases.

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 is used for rotatably supporting a vehicle wheel on a suspension device and for detecting the rotation speed of the wheel.

[0002]

2. Description of the Related Art A vehicle wheel is rotatably supported by a suspension system and the rotational speed of the wheel is detected in order to control an antilock brake system (ABS) or a traction control system (TCS). As a rolling bearing unit with a rotation speed detector for
Conventionally, various structures are known. Each of the rotation speed detecting devices incorporated in such a rolling bearing unit with a rotation speed detecting device includes a tone wheel that rotates together with the wheel and a sensor that outputs an output signal that changes at a frequency proportional to the rotation speed of the tone wheel. Prepare Various types of tone wheels and sensors have been conventionally known. Among these, the so-called passive type, which uses a magnetic material as the tone wheel and changes the voltage induced in the coil forming the sensor according to the rotation of the tone wheel, is an expensive component. It is widely used because it is not used. Further, in such a passive type rotation speed detecting device, in order to increase the output of the sensor, the sensor may be configured in an annular shape, as described in, for example, the Japan Institute of Invention Publication No. 94-16051. It has been known for a long time.

8 to 9 show a rolling bearing unit with a rotation speed detecting device described in this publication. An outer end portion of the hub 1 forming the rotating wheel (outside means a side outside the width direction of the vehicle when assembled to the vehicle, left in each drawing), and a flange portion for fixing the wheel on the outer peripheral surface. Forming 2,
An inner ring raceway 3a, which is a rotation-side raceway surface, and a step portion 4 are formed on the outer peripheral surface of the intermediate portion, which is the second peripheral surface. In addition, on the outer peripheral surface of the hub 1, an inner ring member 5 that also forms a rotating ring, in which an inner ring raceway 3b that is a rotation side raceway surface is formed on the outer peripheral surface that is also the first peripheral surface, and an outer end surface thereof is formed. Is externally fitted and supported in a state of abutting against the step portion 4. The inner ring raceway 3a is formed on an inner ring member (not shown) separate from the hub 1, instead of being formed directly on the outer peripheral surface of the hub 1, and the inner ring member and the inner ring member 5 are connected to each other by the hub. There is also a case where it is externally fitted and fixed to 1.

Further, a male screw portion 6 is provided on the hub 1 near its inner end.
Is formed. Then, the inner ring member 5 is fixed to a predetermined portion of the outer peripheral surface of the hub 1 by a nut 7 screwed into the male screw portion 6 and further tightened. A mounting portion 9 for fixing the outer ring-equivalent member 8 to the suspension device is provided on the outer peripheral surface of the intermediate portion of the outer ring-equivalent member 8 which is a fixed ring and is arranged around the hub 1. Further, on the inner peripheral surface of the member 8 corresponding to the outer ring, which is the first peripheral surface, each of the inner ring raceways 3 is formed.
Outer ring raceway 10 that is a fixed-side raceway surface that faces a and 3b.
a and 10b are formed. A plurality of rolling elements 11, 11 are provided between the inner ring raceways 3a, 3b and the outer ring raceways 10a, 10b, respectively, so that the hub 1 can freely rotate inside the outer ring equivalent member 8. . still,
In the illustrated example, balls are used as the rolling elements 11, 11, but in the case of a rolling bearing unit for an automobile that is heavy, tapered rollers may be used as the rolling elements.
Further, a seal ring 12 is mounted between the inner peripheral surface of the outer end of the outer ring member 8 and the outer peripheral surface of the hub 1, so that the inner ring surface of the outer ring member 8 and the outer peripheral surface of the hub 1 are attached. Between the rolling elements 11 and 11 closes the outer end opening of the space in which the plurality of rolling elements 11, 11 are provided.

At the inner end portion of the inner ring member 5 (inside means the side closer to the widthwise center of the vehicle when assembled to the vehicle, right in each figure), there is a portion that is off the inner ring raceway 3b. , The base end of the tone wheel 13 (the left end of FIGS. 8-9)
Is fitted and fixed. The tone wheel 13 is formed of a magnetic metal plate such as a steel plate so as to have an annular shape (short cylindrical shape). The tone wheel 13 includes a small-diameter portion 14 and a large-diameter portion 15 which are concentrically formed with each other and are continuous by a step portion 16. In such a tone wheel 13, the large diameter portion 15 is externally fitted to the outer peripheral surface of the end portion of the inner ring member 5, and the step portion 16 is brought into contact with the end edge portion of the inner ring member 5 to form the inner ring. It is supported and fixed to the member 5. Therefore, the small diameter portion 14 which is a cylindrical portion is supported concentrically with the inner ring member 5. Then, a plurality of through holes 17 are formed in the small diameter portion 14 as the rotation side thinning portion at equal intervals in the circumferential direction. Each through hole 17 has the same shape, and is a rectangular shape that is long in the axial direction (the left-right direction in FIGS. 8 to 9).

The inner end opening of the member 8 corresponding to the outer ring is closed by a cover 18 formed in a cylindrical shape with a bottom by drawing a metal plate such as a stainless steel plate or an aluminum alloy plate. On the inner peripheral side of the cylindrical portion 19 forming the cover 18,
A synthetic resin 21 in which an annular sensor 20 is embedded is held and fixed. The sensor 20 includes a permanent magnet 22, a stator 23 made of a magnetic material such as a steel plate, and a coil 24. These members 22, 23 and 24 are embedded in the synthetic resin 21. Due to this, the whole is configured in an annular shape.

Of the constituent members of the sensor 20, the permanent magnet 22 is formed in an annular shape (annular shape) as a whole, and is magnetized in the diametrical direction. And this permanent magnet 2
The inner peripheral surface of 2 is opposed to the outer peripheral surface of the portion of the small diameter portion 14 forming the tone wheel 13 where the through hole 17 is not formed, through a minute gap 25.
The stator 23 has a substantially J-shaped cross section and is formed in an annular shape as a whole. Then, the inner peripheral surface of the end portion of the outer cylindrical portion 26 constituting the stator 23 and the outer peripheral surface of the permanent magnet 22 are brought close to or in contact with each other. Further, the inner peripheral surface of the inner cylindrical portion 27 which constitutes the stator 23 is made to face a part of the tone wheel 13 where the plurality of through holes 17 are formed. Further, the inner cylindrical portion 27
A plurality of cutouts 28, which are fixed-side thinned portions, are formed in the through holes 17, 1 over the circumferential direction of the inner cylindrical portion 27.
7 and the same pitch (center angle pitch). Therefore, the inner cylindrical portion 27 is formed in a comb shape.

Further, the coil 24 is formed in an annular shape by winding a conductive wire around a bobbin 29 made of a non-magnetic material,
It is arranged on the inner peripheral side portion of the outer cylindrical portion 26 constituting the stator 23. The electromotive force generated in the coil 24 is taken out from the connector 30 protruding on the outer surface of the cover 18.

When the rolling bearing unit with a rotational speed detecting device constructed as described above is used, when the tone wheel 13 rotates together with the hub 1, the magnetic flux density in the stator 23 facing the tone wheel 13 changes, and Coil 2
The voltage induced in 4 changes at a frequency proportional to the rotation speed of the hub 1. The principle that the voltage induced in the coil 24 changes in response to the change in the density of the magnetic flux flowing through the stator 23 is the same as in the case of a rotation speed detecting sensor that has been widely known from the past. The reason why the density of the magnetic flux flowing through the stator 23 changes according to the rotation of the tone wheel 13 is as follows.

Since the plurality of through holes 17 formed in the tone wheel 13 and the notches 28 formed in the stator 23 have the same pitch, they face each other at the same time over the entire circumference as the tone wheel 13 rotates. There is a moment. Then, at the moment when each of the through holes 17 and each of the notches 28 face each other, between the column portion which is a magnetic body existing between the adjacent through holes 17 and between the adjacent notches 28 also. The existing tongue, which is a magnetic body, faces each other through the minute gap 25. In this way, in the state where the column portion and the tongue piece, each of which is a magnetic body, face each other, a high-density magnetic flux flows between the tone wheel 13 and the stator 23.

On the other hand, the through hole 17 and the notch 2
If the phase with 8 is shifted by half, the above tone wheel 1
The density of the magnetic flux flowing between the stator 3 and the stator 23 becomes low. That is, in this state, the through hole 17 provided in the tone wheel 13 faces the tongue piece and the stator 23
The notch 28 provided on the column faces the column portion. In this state where the pillar portion faces the notch 28 and the tongue piece faces the through hole 17, respectively, in the tone wheel 13 and the stator 2 described above.
There is a relatively large gap between 3 and 3 over the entire circumference. Then, in this state, the density of the magnetic flux flowing between the both members 13 and 23 becomes low. As a result, the voltage induced in the coil 24 changes in proportion to the rotation speed of the hub 1.

The sensor 20 operates as described above to change the output voltage induced in the coil 24 at a frequency proportional to the rotation speed of the hub 1, but the opening end portion of the member 8 corresponding to the outer ring is changed. , Originally there is an annular space. Therefore, the sensor 20 can be installed in a limited space, and the output of the sensor 20 can be made sufficiently large to make the hub 1
It is possible to reliably detect the rotation speed of a wheel that rotates with the wheel.
That is, the permanent magnet 22, the stator 23, and the coil 24 that constitute the sensor 20 are respectively the tone wheel 1
It is formed in an annular shape surrounding the entire circumference of 3. Since the magnetic flux emitted from the permanent magnet 22 is caused to flow over the entire circumference of the stator 23, the amount of magnetic flux flowing inside the stator 23 can be sufficiently increased as a whole of the stator 23. Therefore, the voltage change of the coil 24 corresponding to the density change of the magnetic flux passing through the stator 23 can be increased.

[0013]

In the case of the rotational speed detecting device having the heretofore known annular sensor 20 configured and functioning as described above, the rod-shaped sensor known before that is used. Larger output can be obtained compared to the structure used. However, when the sensor 20 is formed in an annular shape and the permanent magnet 22, the stator 23, and the coil 24 are made large, the degree of improvement in output is small, and improvement is desired in order to obtain a larger output. There is.

As described above, the reason why the degree of output improvement is small in proportion to the increase in size of the constituent members 22 to 24 is that the magnetic resistance between the tone wheel 13 and the permanent magnets 22 and the stator 23 is large, and each of these is large. The amount of magnetic flux flowing in the magnetic circuit including the members 13, 22 and 23 is small,
The amount of change in the magnetic flux flowing through the stator 23 may be small.
That is, in the case of the conventional structure shown in FIGS. 8 to 9, the inner cylindrical portion 2 forming the inner peripheral surface of the permanent magnet 22 and the stator 23.
7 and the small diameter portion 1 forming the tone wheel 13
The outer peripheral surface of No. 4 opposes via the minute gap 25. Since air having a large magnetic resistance exists in the minute gap 25,
The resistance to the magnetic flux flowing through the magnetic circuit increases in this minute gap 25 portion. As a result, at the moment when the through holes 17 and the notches 28 face each other,
The amount of change in the magnetic flux density between the moments when the phases of the coils 28 shift by half is reduced, and the extent to which the output voltage induced in the coil 24 increases becomes small.

For example, when a pair of magnetic materials have an opposing area of A and are opposed to each other via an air layer having a thickness of L, the magnetic resistance R _m in this air layer portion is expressed by the following equation. . still,
μ ₀ is the magnetic permeability of air. R _m = L / (μ ₀ · A) As is clear from this equation, in order to reduce the magnetic resistance R _m in the minute gap 25 in order to increase the amount of magnetic flux flowing in the magnetic circuit, It is necessary to reduce the thickness L of the minute gap 25 or increase the facing area A of the members 13, 22, 23 that face each other through the minute gap 25. Among them, the thickness of the minute gap 25 is conventionally a small value of 1 mm or less (for example, about 0.5 mm), and it is difficult to further reduce the thickness in consideration of machining accuracy and assembly accuracy. The rolling bearing unit with a rotation speed detecting device of the present invention was invented in view of such circumstances, and the output of the sensor is increased by increasing the facing area.

[0016]

A rolling bearing unit with a rotation speed detecting device according to the present invention has a fixed side raceway surface on a first peripheral surface, like the above-described conventional rolling bearing unit with a rotation speed detecting device. A fixed ring, a cover fixed to an end of the fixed ring, a rotary ring having a rotation side raceway surface on a second peripheral surface facing the first peripheral surface, the fixed side raceway surface and the rotation side Fixed to the end of the rotary wheel, which has a plurality of rolling elements rotatably provided between the raceway surface and a plurality of rotation-side thinned portions formed at equal intervals in the circumferential direction. An annular tone wheel made of a magnetic material and a sensor held inside the cover so as to face the tone wheel are provided.

Particularly, in the rolling bearing unit with a rotation speed detecting device of the present invention, the tone wheel is diametrically bent from a cylindrical portion concentric with the rotating wheel and the fixed wheel and one axial end of the cylindrical portion. There is a step portion, and the rotation-side thinning portion is provided on the peripheral surface of the cylindrical portion.
In addition, the sensor includes at least a permanent magnet formed in an annular shape, a stator made of a magnetic material, and a coil. Further, a fixed-side thinned portion is formed at a portion electrically connected to one end surface in the magnetizing direction of the permanent magnet at a pitch equal to that of the rotary-side thinned portion, and the fixed-side thinned portion is formed. The portion formed with is opposed to a portion of the peripheral surface of the cylindrical portion where the rotation-side thinned portion is formed via a minute gap.
The one end of the stator is in contact with or close to the other end surface of the permanent magnet in the magnetizing direction. The other end of the stator faces a part of the peripheral surface of the cylindrical portion and the step portion with a minute gap. Further, the coil is attached to the stator around the entire circumference thereof.

[0018]

The rolling bearing unit with a rotation speed detecting device of the present invention constructed as described above rotatably supports the wheel on the suspension device, and the operation itself when detecting the rotation speed of the wheel is as described above. This is similar to the conventional rolling bearing unit with a rotation speed detecting device. In particular, in the case of the rolling bearing unit with a rotation speed detecting device of the present invention, since the other end of the stator faces a part of the peripheral surface of the cylindrical portion and the step portion with a minute gap, The facing area between the stator and the tone wheel can be widened to reduce the magnetic resistance between the stator and the tone wheel. As a result, the output of the sensor can be improved by increasing the magnetic flux flowing in the magnetic circuit including the stator and the tone wheel.

[0019]

1 and 2 show a first embodiment of the present invention. The feature of the present invention is that the output of the sensor 20a (and the sensors 20b and 20c described later) is increased, so that the tone wheel 13 and the stator 23 (and the stator 23 described later) that configures the sensor 20a (20b, 20c).
a, 23b) so as to widen the facing area.
Since the configuration and operation of the other parts are almost the same as those of the above-mentioned conventional structure, the same parts are designated by the same reference numerals, and overlapping description will be omitted or simplified. Hereinafter, the characteristic parts of the present invention will be mainly described. explain.

In the small diameter portion 14 formed in the tone wheel 13 which is a cylindrical portion concentric with the rotary wheel and the fixed wheel, a plurality of through holes 17, 17 each of which is a rotary side thinning portion, are provided around the circumference. They are formed at equal intervals in the direction. Further, a step portion 16 is bent outward from the outer end of the small diameter portion 14 in the diametrical direction. Then, a large diameter portion 15 continuous from the outer peripheral edge of the step portion 16 in the opposite direction to the small diameter portion 14 is provided.
Is fitted and fixed to the inner ring 5.

The permanent magnet 22a is magnetized in the diameter direction over the entire circumference. Then, as shown in detail in FIG. 4, the inner peripheral surface of the permanent magnet 22a itself, which is a portion electrically connected to one end surface in the magnetizing direction of the permanent magnet 22a, is formed with irregularities in the circumferential direction. Then, the permanent magnet 22a is formed in the shape of an internal gear. In this way, the pitch of the recesses 31, 31 and the protrusions 32, 32 alternately formed on the inner peripheral surface of the permanent magnet 22a is equal to the pitch of the through holes 17, 17 formed in the small diameter portion 14 of the tone wheel 13. Are equal. or,
The recesses 31 and 31 correspond to the fixed-side thinned portions, respectively. The inner peripheral surface of the permanent magnet 22a is formed on the outer peripheral surface of a portion of the small diameter portion 14 where the through holes 17, 17 are formed.
They are opposed to each other via the minute gap 25. Therefore, at the moment when any one of the protrusions 32 faces the through hole 17, all the other protrusions 32 also face the other through holes 17, 17. On the contrary, at the moment when any of the concave portions 31 faces the through hole 17, all of the other concave portions 31 also face the other through holes 17, 17. If the permanent magnet 22a is a plastic magnet, it is possible to easily form irregularities on the inner peripheral surface of the permanent magnet 22a by using a molding die having a slightly complicated shape. Therefore, the increase in processing cost is small compared with the case where a mere annular permanent magnet is used.

The stator 23 has an inner end portion (the right end portion in FIGS. 1 to 3) of the outer cylindrical portion 26, which is one end portion thereof, and an inner end edge (the right end edge in FIGS. 1 to 3) of the inner cylindrical portion 27. ) Is brought into contact with or close to the outer peripheral surface which is the other end surface of the permanent magnet 22a in the magnetizing direction. Therefore, the outer peripheral surfaces of the permanent magnets 22a and the stator 23 are magnetically connected. Further, the inner cylindrical portion 27 formed at the other end of the stator 23 and the circular ring portion 34 that connects the inner cylindrical portion 27 and the outer cylindrical portion 26 are opposed to the tone wheel 13 via a minute gap 25. I am letting you.
That is, the inner peripheral surface of the inner cylindrical portion 27 is provided with the through hole 17 as a part of the small diameter portion 14 that constitutes the tone wheel 13.
The inner ring-shaped portion of the circular ring portion 34 faces the side surface of the stepped portion 16 via a minute gap 25 at a portion deviated from 17.

Further, the coil 24 constituting the sensor 20a is attached to the intermediate portion of the stator 23 over the entire circumference thereof while being sandwiched between the outer cylindrical portion 26 and the inner cylindrical portion 27. The coil 24 is constructed by winding a conductive wire around a bobbin 29, which is made of a non-magnetic material such as synthetic resin and has a U-shaped cross section, and is formed into an annular shape. The end portion of this lead wire is taken out through a through hole (not shown) formed in the stator 23 and connected to a terminal inside the connector 30.

In the case of the rolling bearing unit with the rotation speed detecting device of the present embodiment configured as described above, the permanent magnet 2 is used.
The small diameter portion 1 which constitutes the inner peripheral surface of 2a and the tone wheel 13.
The magnetic resistance is changed between the sensor 20a and the outer peripheral surface of the sensor 20a.
The density of the magnetic flux flowing in the stator 23 constituting the above is changed. This mechanism will be described in detail with reference to FIGS. First, as shown in FIG. 3 (A), as the tone wheel 13 rotates, all the protrusions 3 of the permanent magnet 22a are rotated.
The magnetic resistance between the tone wheel 13 and the permanent magnet 22a becomes small at the moment when the two faces the column portion 33 between the adjacent through holes 17. Therefore, a large amount of magnetic flux flows (the magnetic flux density increases) in the magnetic circuit including the stator 23. On the other hand, as shown in FIG. 3 (B), as the tone wheel 13 rotates, at the moment when all the concave portions 31 of the permanent magnet 22 a face the pillar portions 33, the tone wheel 13 and the permanent magnet 22 a become permanent. The magnetic resistance with the magnet 22a increases. Therefore, the magnetic flux flowing in the magnetic circuit including the stator 23 decreases (the magnetic flux density decreases). As described above, the magnetic resistance in the magnetic circuit including the stator 23 changes as the tone wheel 13 rotates, and as a result, the coil 24 changes at a frequency proportional to the rotation speed of the tone wheel 13. A voltage is evoked.

Particularly, in the case of the rolling bearing unit with the rotational speed detecting device of the present embodiment, the entire inner peripheral surface of the inner cylindrical portion 27 which is the other end portion of the stator 23 and the side surface of the circular ring portion 34 near the inner peripheral portion. (Left side of FIGS. 1 to 3) is the tone wheel 1
Since a part of the outer peripheral surface of the small diameter portion 14 which is the peripheral surface of the cylindrical portion forming part 3 and the side surface of the stepped portion 16 face each other with a minute gap 25, the stator 23 and the tone wheel 1
The facing area with 3 can be widened. The stator 23 and the tone wheel 13 are increased in proportion to the increase in the facing area.
The magnetic resistance between and can be reduced. As a result, the magnetic flux flowing in the magnetic circuit including the stator 23 and the tone wheel 13 can be increased to improve the output of the sensor 20a.

Next, FIGS. 5 to 6 show a second embodiment of the present invention. In the case of the present embodiment, the permanent magnet 22b constituting the sensor 20b is formed in an annular shape such as a short cylindrical shape, and is magnetized in the axial direction (the left-right direction in FIGS. 5 to 6) over the entire circumference. ing. Then, one end of the stator 23b is abutted against one end surface (the left end surface in FIGS. 5 to 6) of the permanent magnet 22b, which is the other end surface in the magnetization direction. The stator 23b is formed by forming a magnetic material such as a mild steel plate into an annular shape with an L-shaped cross section. The inner peripheral surface of the stator 23b is a portion of the small diameter portion 14 of the tone wheel 13 which is out of the through hole 17. On the outer peripheral surface of
The outer side surface (the left side surface of FIGS. 5 and 6) on the side surface of the stepped portion
They are opposed to each other via a minute gap 25.

On the other hand, one end of another stator 35 is abutted against the other end surface (right end surface in FIGS. 5 to 6) of the permanent magnet 22b which is one end surface in the magnetizing direction. Further, the other stator 35 is constituted, and the notches 37 and 37, which are the fixed-side thinning portions, are provided in the circumferential direction in the cylindrical portion 36 facing the small diameter portion 14 with the minute gap 25 therebetween. Are formed at equal intervals. Therefore, the inner peripheral half of the other stator 35 is formed in a comb tooth shape, and the adjacent notches 3 are formed.
Protrusions 39 and 39 are formed between 7 and 37. In addition, the pitch of the notches 37, 37 is such that the through holes 17, 17
It is equal to the pitch. In the case of the present embodiment, these notches 3 are formed as the tone wheel 13 rotates.
7 and 37 and the through holes 17 and 17 change the phase, the density of the magnetic flux flowing through the stator 23b and the other stator 35 changes, which is induced in the coil 24 attached to the two stators 23b and 35. Voltage changes.

First, as shown in FIG. 6 (A), as the tone wheel 13 rotates, all the projecting pieces 39 of another stator 35 adjoin the through holes 17, and the column portion 33 between the adjacent holes 17. The tone wheel 13 and the permanent magnet 22
The magnetic reluctance with b becomes small. Therefore, the stator 2
Many magnetic fluxes flow in the magnetic circuit including 3b and 35.
On the other hand, as shown in FIG. 6B, at the moment when all the notches 37 of the other stator 35 face the pillar portion 33 with the rotation of the tone wheel 13, The magnetic resistance between the permanent magnet 22b and the permanent magnet 22b increases. Therefore, the magnetic flux flowing in the magnetic circuit including the stators 23b and 35 is reduced. In this way, the stator 23
As a result of the magnetic resistance in the magnetic circuit including b and 35 changing with the rotation of the tone wheel 13, a voltage that changes at a frequency proportional to the rotation speed of the tone wheel 13 is generated in the coil 24. To be done.

The difference between this embodiment and the first embodiment described above is that the magnetizing direction of the permanent magnet 22b is different, and another stator is provided between one end face of the permanent magnet 22b in the magnetizing direction and the tone wheel 13. 35 is provided. Other configurations and operations are similar to those of the first embodiment described above. 5 to 6 showing the present embodiment, the bobbin is omitted.

Next, FIG. 7 shows a third embodiment of the present invention. In this embodiment, the peripheral speed of the tone wheel 13a is increased in order to increase the output of the sensor 20c. Therefore, the tone wheel 13a used in this embodiment is used.
Comprises a small-diameter portion 14a and a large-diameter portion 15a, which are concentric with each other, connected by a step portion 16a. In such a tone wheel 13a, the small-diameter portion 14a is fitted on the inner end portion of the inner ring member 5 outside the inner ring raceway 3b, so that the hub 1
It can be rotated together with it. The large diameter portion 15a, which is a cylindrical portion that is concentric with the hub 1 that is a rotating wheel and the outer ring equivalent member 8 that is a fixed wheel, has a plurality of through holes 17, 17 that are rotating-side thinning portions, respectively They are formed at equal intervals in the direction.

The sensor 20c includes a permanent magnet 22c, a stator 23a, and a coil 24, each of which is formed in an annular shape. The permanent magnet 22c among them is magnetized in the diameter direction over the entire circumference. And this permanent magnet 22
Gear-shaped concavities and convexities consisting of concave portions 31 and 31 and convex portions 32 and 32 are formed on the outer peripheral surface which is one end surface in the magnetizing direction of c. The portion where the through holes 17, 17 are formed is opposed to each other via a minute gap 25a. The concave portion 31 is the fixed-side thinning portion.

The stator 23a is formed by forming a magnetic metal plate such as a mild steel plate into a substantially J-shaped cross section, and has an outer cylindrical portion 26a and an inner cylindrical portion 27a which are concentric with each other. Of the two cylindrical portions 26a and 27a, the inner cylindrical portion 27a
Of the outer cylindrical portion 26a (right end edge of FIG. 7) in the axial direction (left and right direction of FIG. 7).
Overhangs. The permanent magnet 22c, which is the other end surface in the magnetizing direction, is formed on the outer peripheral surface of the portion of the inner cylindrical portion 27a protruding from the leading edge of the outer cylindrical portion 26a.
The inner peripheral surface of the is contacted with or brought close to.

The outer peripheral surface of the outer cylindrical portion 26a formed at the other end of the stator 23a is the same as the inner peripheral surface of a portion of the large-diameter portion 15a which is separated from the through holes 17, 17. The side surface of the circular ring portion 34a faces the stepped portion 16a via a minute gap 25a.

The sensor 20c configured as described above has a synthetic resin 21a whose cross section has a laterally convex shape and which is formed in an annular shape as a whole.
Embedded within. Then, the synthetic resin 21a is internally fitted and fixed to the cover 18a fitted to the inner end opening of the outer ring equivalent member 8. In this state, the inner peripheral surface of the large diameter portion 15a of the tone wheel 13a is on the outer peripheral surface of the sensor 20b supported by the synthetic resin 21a, and the step portion 16a is also on the outer end surface thereof via the minute gaps 25a. To face each other. In the illustrated example, a bottomed cylindrical convex portion 38 is formed on the bottom plate portion of the cover 18a, and the synthetic resin 21a is
The convex portion 38 is externally fitted. Therefore, this synthetic resin 2
A sufficient supporting strength for the cover 1a of 1a is ensured.

The rolling bearing unit with the rotation speed detecting device of the present embodiment configured as described above rotatably supports the wheel on the suspension device, and the action itself at the time of detecting the rotation speed of the wheel is as follows. It is the same as the rolling bearing unit for rotational speed detection of the first embodiment described above except that the inner side and the outer side in the diametrical direction are reversed. Tone wheel 13 with hub 1
When a rotates, the magnetic flux density in the stator 23a facing the tone wheel 13a changes, and the coil 24
The voltage induced by the voltage changes at a frequency proportional to the rotation speed of the hub 1.

Particularly, in the case of the rolling bearing unit with the rotation speed detecting device of the present embodiment, since the inner peripheral surface of the large diameter portion 15a formed on the tone wheel 13a and the outer peripheral surface of the permanent magnet 22c are opposed to each other, the magnetic flux In order to change the density, the diameter of the portion that changes the magnetic resistance can be increased. That is, the sensor 20c in which the thickness of the portion that changes the magnetic resistance is increased to some extent in the diameter direction due to the presence of the coil 24 and the like.
Since it is arranged on the outer peripheral side, the diameter of the portion that changes the magnetic resistance, such as the large diameter portion 15a, can be increased. As a result, the through hole 17 and the permanent magnet 22 which are both the rotating side and the fixed side thinned portions.
The width dimension of the column portion 33 (FIGS. 3 and 6) existing between the adjacent through holes 17, 17 is improved by sufficiently securing the number of irregularities formed on the outer peripheral surface of c to improve the detection accuracy of the rotation speed. Can be sufficiently secured to increase the output of the sensor. The present invention can be applied not only to the structure in which the outer ring side rotates as in the illustrated embodiment, but also to the structure in which the inner ring side rotates. In this case, the sensor is preferably provided on the inner peripheral side of the tone wheel.

[0037]

Since the rolling bearing unit with the rotational speed detecting device of the present invention is constructed and operates as described above,
A large output can be obtained, and the rotation speed of the wheel can be reliably detected.

[Brief description of drawings]

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

FIG. 2 is an enlarged view of the right part of FIG.

FIG. 3 is a view for explaining a situation where an output is generated in a sensor,
The partial expanded sectional view of a tone wheel and a sensor.

FIG. 4 is a perspective view of a permanent magnet that constitutes a sensor.

FIG. 5 is a view similar to FIG. 2, showing a second embodiment of the present invention.

FIG. 6 is a view for explaining a situation where an output is generated in a sensor,
The partial expanded sectional view of a tone wheel and a sensor.

FIG. 7 is a view similar to FIG. 2, showing a third embodiment of the present invention.

FIG. 8 is a sectional view showing an example of a conventional structure.

9 is an enlarged view of part A in FIG.

[Explanation of symbols]

 1 hub 2 flange part 3a, 3b inner ring raceway 4 step part 5 inner ring member 6 male screw part 7 nut 8 outer ring equivalent member 9 mounting part 10a, 10b outer ring raceway 11 rolling element 12 seal ring 13, 13a tone wheel 14, 14a small diameter part 15 , 15a Large diameter part 16, 16a Step part 17 Through hole 18, 18a Cover 19 Cylindrical part 20, 20a, 20b, 20c Sensor 21, 21a Synthetic resin 22, 22a, 22b, 22c Permanent magnet 23, 23a, 23b Stator 24 Coil 25, 25a Micro gap 26, 26a Outer cylindrical portion 27, 27a Inner cylindrical portion 28 Notch 29 Bobbin 30 Connector 31 Recessed portion 32 Convex portion 33 Pillar portion 34, 34a Ring portion 35 Another stator 36 Cylindrical portion 37 Notched portion 38 Convex Part 39 Projection piece

Claims (1)

[Claims] 1. A fixed ring having a fixed side raceway surface on a first peripheral surface, a cover fixed to an end portion of the fixed ring, and a second peripheral surface opposed to the first peripheral surface. A rotating wheel having a side raceway surface, a plurality of rolling elements rotatably provided between the fixed side raceway surface and the rotating side raceway surface, and a plurality of rotations formed at equal intervals in the circumferential direction. An annular tone wheel made of a magnetic material, which has a side wall removal portion and is fixed to the end of the rotary wheel, and a sensor held inside the cover in a state of facing the tone wheel are provided. In the rolling bearing unit with the rotation speed detecting device, the tone wheel has a cylindrical portion concentric with the rotating wheel and the fixed wheel and a step portion diametrically bent from one axial end of the cylindrical portion. The thinning part is provided on the peripheral surface of the cylindrical part, and the sensor , At least each of which is provided with a permanent magnet and a stator made of a magnetic material and a coil each formed in an annular shape, and a fixed-side thinning portion is provided in a portion that is magnetically connected to one end face in the magnetization direction of the permanent magnet, It is formed at the same pitch as the rotation-side thinned portion, and the portion where the fixed-side thinned portion is formed is the portion where the rotation-side thinned portion is formed in a part of the peripheral surface of the cylindrical portion, The stator faces each other through a minute gap, and one end of the stator is brought into contact with or close to the other end face of the permanent magnet in the magnetizing direction, and the other end of the stator is a peripheral surface of the cylindrical portion. A rolling bearing unit with a rotation speed detecting device, wherein a part of the coil is opposed to the stepped portion through a minute gap, and the coil is attached to the stator over the entire circumference thereof.