JPH06265562A - Rolling bearing unit equipped with rotational speed detector - Google Patents

Abstract

PURPOSE:To increase sensor output by preventing saturation of flux within a yoke. CONSTITUTION:A sensor 33 comprises first and second yokes 34,35, a permanent magnet 36, and a coil 37. Immediately upon opposing one end face 34a of the first yoke 34 and the other end face 35b of the second yoke 35 to a tongue 30, one end face 35a of the second yoke 35 and the other end face 34b of the first yoke 34 oppose to a notch 31. Consequently, electromotive forces are induced alternately in reverse directions in the coil 37 as a tone wheel 29 rotates.

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 incorporated in an antilock brake system (ABS) or a traction control system (TCS) to rotate a vehicle wheel with respect to a suspension device. It is freely supported and used to detect the rotation speed of this wheel.

[0002]

2. Description of the Related Art The wheels of a motor vehicle must be rotatably supported on a suspension system. Further, in order to control the antilock brake system (ABS) or the traction control system (TCS), it is necessary to detect the rotation speed of the wheels. For this purpose, a rolling bearing unit with a rotation speed detecting device is disclosed in
No. 56, No. 5-4021, or US Pat. No. 5
It has been proposed in the past, as described in the specification of No. 063345. 14-15 show the structure therein, which is described in US Pat. No. 5,063,345.

The tone wheel 1 is entirely made of a magnetic material, and has gear-like irregularities 2 formed on the outer peripheral edge thereof.
The tone wheel 1 rotates with the wheels. The sensor 3 which is supported on the side of the suspension device and does not rotate includes a permanent magnet 4 magnetized in the axial direction (vertical direction in FIG. 14), a yoke 5 made of a magnetic material, and wound around the yoke 5. And a coil 6. The base end surface (upper end surface in FIG. 14) of the yoke 5 is abutted against one end surface (lower end surface in FIG. 14) of the permanent magnet 4, and the tip end surface (lower end surface in FIG. 14) of the yoke 5 is It opposes the unevenness 2. Therefore, a magnetic field as shown by the broken line in FIG. 14 is formed around the permanent magnet 4 and the yoke 5.

The density of the magnetic flux forming this magnetic field becomes high when the tip surface of the yoke 5 and the convex portion of the unevenness 2 face each other, and the tip surface faces the concave portion of the unevenness 2. If it is, it will be lower. In this way, as the magnetic flux density of the magnetic field formed around the coil 6 changes,
The electromotive force induced in this coil 6 portion changes as shown in FIG. The frequency at which the electromotive force changes is proportional to the rotational speed of the wheel. Therefore, the above electromotive force is
If it is input to the controller 7 of
S can be controlled appropriately.

[0005]

However, the conventional rolling bearing unit with the rotational speed detecting device, which is constructed and operates as described above, has the following problems. That is, it is not always possible to secure a sufficient mounting space for mounting the sensor 3 in the rotation supporting portion of the wheel.
Therefore, it is necessary to downsize the sensor 3, but if the sensor 3 is simply downsized, the output of the sensor 3 (see FIG.
The difference V) between the highest voltage and the lowest voltage shown in
The reliability of rotation speed detection is impaired.

That is, in order to miniaturize the sensor 3, it is necessary to use a yoke having a small diameter, but in order to secure the output of the sensor 3, the permanent magnet 4 has a strong magnetic force (magnetic flux). High density) must be used. As a result, the magnetic flux is easily saturated inside the yoke 5. When the magnetic flux is saturated in the yoke 5, there is little change in the magnetic flux density between the state in which the tip surface of the yoke 5 faces the convex portion of the unevenness 2 and the state in which it faces the concave portion, and the output is extremely high. It gets smaller.

[0007] As a rolling bearing unit with a rotation speed detecting device incorporating a sensor capable of being installed in a limited space and at the same time preventing saturation of magnetic flux in the yoke and obtaining a sufficient output, Japanese Patent Laid-Open No. 5-4021 discloses a structure as shown in FIGS.

In the case of the structure described in this publication, the projection 9 is brought into contact with the inner peripheral side surface of the permanent magnet 8 magnetized in the diameter direction of the tone wheel 1, and the intermediate portion thereof is brought into contact with the outer peripheral side surface of the permanent magnet 8. Bent portions 11, 11 are provided at both ends of the yoke 10 made of a magnetic material. The projection 9 and the bent portions 11, 11 and the projections forming the projections and depressions 2 on the outer peripheral edge of the tone wheel 1 are arranged to face each other at the same time. Further, in the coil 12 wound around the yoke 10, the first coil portion 12a and the second coil portion 12b whose winding directions are opposite to each other are connected in series.

In the case of the structure constructed as described above, the magnetic flux generated from the outer peripheral side surface of the permanent magnet 8 moves inside the yoke 10 by 2
Since the current flows separately in the system, the magnetic flux is less likely to be saturated in the yoke 10 as compared with the structure shown in FIG. 14, but it is still difficult to obtain a reliable effect. That is, FIGS.
In the case of the structure shown in FIG. 7, assuming that the cross-sectional areas of the yokes 5 and 10 are the same, a magnetic flux density up to about twice that of the structure shown in FIG. If the permanent magnet 8 included therein is used, the magnetic flux is saturated in the yoke 10 as well, and the output of the sensor 13 is extremely reduced.

The rolling bearing unit with a rotation speed detecting device of the present invention is designed to address the above-mentioned problems.

[0011]

All of the rolling bearing units with a rotation speed detecting device of the present invention, like the above-described conventional rolling bearing unit with a rotation speed detecting device, have a fixed ring that does not rotate during use and a fixed ring thereof. A rotating wheel that is provided concentrically with the wheel and that rotates together with the wheel when in use, a first raceway surface that is formed on the peripheral surface of the fixed wheel that faces the peripheral surface of the rotating wheel, and the peripheral surface of the rotating wheel. With a second raceway surface formed in a portion facing the peripheral surface of the fixed wheel, a plurality of rolling elements provided between these first and second raceway surfaces, supported by the rotating wheel, A tone wheel that rotates with the rotating wheel and a sensor that is supported by the fixed wheel and faces the tone wheel are provided. Then, at least a portion of the tone wheel facing the sensor has a ferromagnetic first portion and a non-magnetic second portion that alternate in the circumferential direction at an equal pitch.

In particular, in the rolling bearing unit with a rotation speed detecting device of the present invention, each of the above-mentioned sensors is provided with a plurality of yokes each made of a magnetic material and having at least four end faces in total. There is. Then, at the moment when any two end faces of the four end faces face the first portion, the other two end faces face the second portion. Further, at least one permanent magnet is provided between the plurality of yokes, with both end faces of the permanent magnet in the magnetizing direction abutting against the respective yokes. Then, due to the magnetic force of the permanent magnet, the rotation of the tone wheel is caused between the end surfaces of any two of the plurality of yokes and between the end surfaces of the other two. Then the magnetic flux flows alternately. Further, a part of the plurality of yokes is provided between the end faces of any two of the above and another
A coil is wound between the end faces of the portion, and the coil is characterized in that there are portions in which the winding directions are opposite to each other with respect to the direction of the alternately flowing magnetic flux.

[0013]

In the rolling bearing unit with rotation speed detecting device of the present invention constructed as described above, when the tone wheel rotates together with the wheel, between the two end faces and between the other two end faces. During this period, magnetic flux alternately flows, and an electromotive force is induced in the coil based on the presence of this magnetic flux. In this case, an electromotive force in the opposite direction is alternately generated between the part wound between the end faces of any two of the above and the part wound between the end faces of the other two places. To do.

Therefore, the magnetic flux is less likely to be saturated in the yoke, and the electromotive force in the opposite direction is alternately generated. As a result, the difference between the maximum value and the minimum value of the voltage can be made sufficiently large, and the rotational speed detection accuracy can be improved. Can be improved.

[0015]

1 to 6 show a first embodiment of the present invention corresponding to claim 2. Double-row outer ring raceway on inner surface 1
The fixed ring 15 having 4 and 14 (first raceway surface) can be supported by the suspension device by the flange 3 formed on the outer peripheral surface thereof. Inside the fixed ring 15, a rotary ring 18 having an inner ring raceway 17, 17 (second raceway surface) facing the outer ring raceways 14, 14 is arranged on the outer peripheral surface. Then, the outer ring raceways 14, 14 of the fixed ring 15 and the rotating ring 18
Between the inner ring raceways 17 and 17 of the retainer 19,
A plurality of rolling elements 20, 20 held by 19 are provided,
A rotary wheel 18 is rotatably supported inside the fixed wheel 15.

The inner end of the rotary wheel 18 (right end in FIG. 1)
A seal assembly 21 is mounted between the outer peripheral surface and the inner peripheral surface of the fixed wheel 15 (the right end in FIG. 1) so that the rolling element 20,
The inner end (right end in FIG. 1) of the space 25 in which 20 is installed is closed. The seal assembly 21 is used for the rotary wheel 1
The inner seal ring 23 is externally fitted and fixed to the shoulder portion of the inner ring 22 that constitutes the inner ring 8, and the outer seal ring 24 is internally fitted and fixed to the inner end portion of the fixed ring 15. The opening of the outer end (left end in FIG. 1) of the space 25 is closed by another seal ring 26.

The inner seal ring 23 comprises a cored bar 27 and a sealing material 28. Then, the inner surface of the cored bar 27 (see FIGS.
A tone wheel 29 is attached to the right side surface of No. 2).
The tone wheel 29, which is manufactured by punching out a magnetic plate, has a gear shape as shown in FIG.
That is, the tongue pieces 30 and 30 which are the first ferromagnetic parts and the notches 31 and 31 which are the second non-magnetic parts are circumferentially provided at the outer peripheral part of the tone wheel 29. They are formed alternately and repeatedly at an equal pitch.

A cover 32, which has an L-shaped cross section and is formed in an annular shape as a whole, is externally fitted and fixed to the inner end opening (the right end opening in FIG. 1) of the fixed ring 15. The sensor 33, which is supported and fixed to the inside, is attached to the tone wheel 29.
The outer surface of the is opposed via a minute gap.

As shown in FIG. 4, the sensor 33 includes first and second yokes 34 and 35, a permanent magnet 36 and a coil 3.
It is composed by combining 7 and. Each of the first and second yokes 34 and 35 is made of a magnetic material in a U shape. The end faces of the first and second yokes 34, 35 are formed on the tone wheel 29.
With the rotation of the tongue 3 of the tone wheel 29
It faces 0, 30 or the notches 31, 31.

The distance between the end faces of the first and second yokes 34 and 35 and the positional relationship between the first and second yokes 34 and 35 satisfy the following conditions. The tongue pieces 30, 30 and the notches 31, 31 are properly set in accordance with the pitch. That is, as shown in FIG. 5, at the moment when the one end face 34a of the first yoke 34 faces any of the tongue pieces 30, the first yoke 34 is
Of the other end surface 34b of the second yoke 35 to one of the notches 31, and the one end surface 35a of the second yoke 35 to the one of the notches 31 of
The other end surface 35b of the second yoke 35 is provided with one of the tongue pieces 3
They are set to face each other at 0. In other words,
The one end face 34a of the first yoke 34 and the other end face 35b of the second yoke 35, and the other end face 34b of the first yoke 34 and the one end face 35a of the second yoke 35 are simultaneously and respectively the above-mentioned tongue pieces. It is made to face 30, 30 or the notches 31, 31.

Further, the permanent magnet 3 is provided between the one end side surface of the first yoke 34 and the one end side surface of the second yoke 35.
6 is the magnetization direction of the permanent magnet 36 (vertical direction in FIG. 5)
The one end face is sandwiched between the first yoke 34 and the other end face in the magnetizing direction is abutted against the second yoke 35, respectively. Therefore, as shown in FIG. 6 described below, magnetic fluxes in opposite directions alternately flow through the first yoke 34 and the second yoke 35 as the tone wheel 29 rotates.

That is, considering the case where the N pole is in contact with the first yoke 34 and the S pole is in contact with the second yoke 35, respectively, as shown in FIG. 34
One end surface 34a of the second yoke 35 and the other end surface 35b of the second yoke 35 face the tongue pieces 30, 30, and the other end surface 3 of the first yoke 34
4b and one end surface 35a of the second yoke 35 are notched 3
At the moment of facing the first and the third, the magnetic flux flows in the second yoke 35 from the other end side toward the one end side. On this occasion,
Only a very small amount of magnetic flux flows in the first yoke 34 whose other end face 34b faces the notch 31.

On the contrary, as shown in FIG. 6B, one end face 34a of the first yoke 34 and the other end face 35b of the second yoke 35 face the notches 31 and 31, and The other end surface 34b of the yoke 34 and one end surface 35 of the second yoke 35
At the moment when a and the tongue pieces 30 and 30 face each other, a magnetic flux flows from the one end side to the other end side in the first yoke 34. At this time, a very small amount of magnetic flux flows in the second yoke 35 whose other end surface 35b faces the notch 31.

In this way, magnetic flux flows in the first yoke 34 and the second yoke 35 alternately and in opposite directions. A single coil 37 is provided in the middle of the first and second yokes 34, 35 through which such magnetic flux flows.
Is wound so that both yokes 34 and 35 are bundled.

The first and second yokes 34, 35, the permanent magnet 36, and the coil 37, which are combined as described above, are molded in a synthetic resin 38 in the combined state to form the sensor 33. Then, the sensor 33 is held inside the cover 32. The sensor 33 is the tone wheel 2
9 can be made long in the circumferential direction, while this sensor 33
It is relatively easy to secure a space in which can be installed in the circumferential direction. Therefore, the design for assembling the sensor 33 is easier than in the case of the conventional structure.

When the rotation speed of the wheel is detected by the rolling bearing unit with the rotation speed detecting device of the present invention configured as described above, together with the wheel fixed to the rotation wheel 18, the tone fixed to this rotation wheel 18 is used. When the wheel 29 rotates, the coil 3 wound around the first and second yokes 34, 35.
Electromotive force is induced in 7. In this case, a part of the coil 37 wound around the middle part of the first yoke 34 (the right half part of FIGS. 5 to 6) and the remaining part of the coil 37 of the second yoke 35. Electromotive force in the opposite direction is alternately generated in the part wound in the part (the left half of the figure).

That is, as shown in FIG. 6 (A), when the magnetic flux flows through the second yoke 35, almost no magnetic flux flows through the first yoke 34. Therefore, the left half portion of the coil 37. When an electromotive force is generated in the coil 37, an electromotive force is hardly generated in the right half portion of the coil 37. On the contrary, as shown in FIG. 6B, when the magnetic flux flows through the first yoke 34,
Almost no magnetic flux flows through the second yoke 35, so that
When electromotive force is generated in the right half portion of the coil 37, almost no electromotive force is generated in the left half portion of the coil 37. Moreover, depending on whether the magnetic flux flows through the first yoke 34 or the second yoke 35, the coil 37
The directions of the magnetic flux with respect to are reversed, and the directions of the electromotive force induced in the coil 37 are also opposite to each other.

As a result, the first and second yokes 34 and 35 are formed.
As a result, it becomes difficult for the magnetic flux to saturate inside, and as a result of the reverse electromotive force being alternately generated in the coil 37, the difference between the maximum value and the minimum value of the voltage can be made sufficiently large. As a result, the output of the sensor 33 can be made sufficiently large, and the accuracy of wheel rotation speed detection can be improved.

Next, FIG. 7 shows a second embodiment of the present invention corresponding to claim 2. In the case of this embodiment, the coil 37a is wound around the first yoke 34 and the second yoke 35 independently of each other in the same direction, and the wound portions are connected in series. Other configurations and operations are similar to those in the case of the first embodiment described above.

Next, FIG. 8 shows a third embodiment of the present invention corresponding to claim 2. In the case of the present embodiment, the retracting portion 39 is formed by projecting the intermediate portion of the first yoke 34 laterally in a U shape, and the intermediate portion of the second yoke 35 is housed in this retracting portion 39. There is. With this configuration,
The thickness dimension of the sensor 33 can be reduced over the axial direction of the rotary wheel 18 (FIG. 1). Other configurations and operations are similar to those of the above-described first embodiment.

Next, FIG. 9 shows a fourth embodiment of the present invention corresponding to claim 2. In the case of the present embodiment, between the intermediate portions of the first yoke 34 and the second yoke 35,
The permanent magnet 36 is sandwiched. Further, the coil 37 is divided into a half portion near one end (upper side in FIG. 9) and a half portion near the other end (lower side in FIG. 9) of the first and second yokes 34, and they are connected in series. is doing. In the case of the present embodiment, as the tone wheel 29 rotates, a half portion of the first yoke 34 near one end and a half portion of the second yoke 35 near the other end and a half portion of the first yoke 34 near the other end. Magnetic flux flows alternately and in opposite directions to the portion and a half portion of the second yoke 35 near one end. Therefore, the electromotive force in the opposite direction alternately flows through the coil 37. Other configurations and operations are similar to those of the above-described first embodiment.

Next, FIGS. 10 to 11 show a fifth embodiment of the present invention, which corresponds to the second aspect. In the case of the present embodiment, as the tone wheel 29a, the tongue piece 30,
30 and the notches 31 and 31 are alternately formed, and the through holes 40 and 40 are formed slightly inside (lower side in FIGS. 10 to 11). In the case of the present embodiment, the portion between the tongue pieces 30, 30 and the adjacent through holes 40, 40 is the first ferromagnetic portion, and the notches 31, 31 are formed.
The through holes 40, 40 are the non-magnetic second portion. The through holes 40, 40 and the tongue pieces 30, 30 are in phase with each other. Further, the first and second yokes 34, 35 each made of a magnetic material and formed in a U-shape are arranged at different positions in the diametrical direction (vertical direction in FIG. 10). The permanent magnet 36 is sandwiched between the end side surfaces of the first and second yokes 34, 35.

At the moment when one end face 34a of the first yoke 34 faces any of the tongue pieces 30, the other end face 34b of the first yoke 34 is placed in any one of the notches 31 and the second yoke 3.
One end surface of 5 faces one of the through holes 40, and the other end surface 35b of the second yoke 35 faces a portion between the adjacent through holes 40, 40. Also in the case of the present embodiment, the coil 37 is formed by winding the first and second yokes 34 and 35 in a bundle.
Electromotive force in the opposite direction is alternately induced as the tone wheel 29a rotates. Other configurations and operations are similar to those of the first embodiment described above.

Next, FIG. 12 shows a sixth embodiment of the present invention corresponding to claim 2. In the case of the present embodiment, the permanent magnet 36 is sandwiched between the intermediate portions of the first and second yokes 34, 35. Other configurations and operations are similar to those of the above-mentioned fifth embodiment.

Next, FIG. 13 shows a seventh embodiment of the present invention, which corresponds to the third aspect. In the case of this embodiment, the sensor 41 includes third, fourth, fifth, and sixth yokes 42 to 45 each made of a magnetic material. One end surface of each of these yokes 42 to 45 (the left end surface in FIG. 13) is
As the tone wheel 29 rotates, it faces the tongue pieces 30, 30 or the notches 31, 31 formed on the outer peripheral edge of the tone wheel 29.

Then, as shown in FIG.
The one end surfaces of the fourth yokes 42, 43 have the tongue pieces 30, 30.
At the moment when the first and second yokes 44 and 45 face each other, one end surfaces of the fifth and sixth yokes 44 and 45 face the notches 31 and 31, and as shown in FIG. At the moment when one end surface of the fifth and sixth yokes 44 and 45 faces the notches 31 and 31, the one end surfaces of the fifth and sixth yokes 44 and 45 face the tongue pieces 30 and 30, respectively.

A first permanent magnet 46 is provided between the third yoke 42 and the fourth yoke 43, and one end face of the first permanent magnet 46 in the magnetizing direction (N pole in the illustrated example). (Side end face)
Is sandwiched between the third yoke 42 and the other end face in the magnetization direction (the end face on the same S-pole side) of the fourth yoke 43 while being abutted against each other. On the other hand, a second permanent magnet 47 is provided between the fifth yoke 44 and the sixth yoke 45, and one end face of the second permanent magnet 47 in the magnetizing direction (the end face on the N pole side).
Is sandwiched between the fifth yoke 44 and the other end face in the magnetization direction (the end face on the same S pole side) to the sixth yoke 45 in abutting state.

Further, a coil 48 is provided on a part of the fourth yoke 43 and a part of the fifth yoke 44, and both yokes 4 are provided.
It is wound so that 3,44 are bundled.

In the case of the rolling bearing unit with a rotation speed detecting device of the present invention constructed as described above, as shown in FIG. 13 (A), one end surface of the third and fourth yokes 42, 43 is a tongue piece. The fifth and sixth yokes 4 facing the 30, 30
When one end faces of 4, 45 face the notches 31, 31,
A magnetic flux flows in the fourth yoke 43 from one end surface toward the other end surface. On the contrary, as shown in FIG.
One end surfaces of the fourth yokes 42 and 43 are formed by the cutouts 31,
The fifth and sixth yokes 44 and 45 are opposed to
When one end surface of the first tongue faces the tongue pieces 30, 30, a magnetic flux flows in the fifth yoke 44 from the other end surface toward the one end surface.

As a result, the fourth and fifth yokes 43,
In the coil 48 wound so as to bundle 44, electromotive forces in opposite directions are alternately induced as the tone wheel 29 rotates. Therefore, as in the case of the first to sixth embodiments described above, it is possible to prevent the magnetic flux from being saturated in each of the yokes 42 to 45 and to increase the output of the sensor.

As a modification of the seventh embodiment described above,
Instead of making the magnetizing directions of the first and second permanent magnets 46, 47 opposite to each other, two coils connected in series are provided, and the winding direction of both coils and the magnetic flux direction are mutually opposite. The tone wheel 29
It is also possible to construct a structure in which electromotive forces in opposite directions are alternately induced in both of the coils in accordance with the rotation of. For example, in FIG.
If it is assumed that the magnetizing direction of the first permanent magnet 46 is reversed in step 3, the third yoke 42 and the fifth yoke 44 (or the fourth yoke 43 and the sixth yoke 45). And to),
It is conceivable to wind the coils in the same direction and connect both coils in series. Further, coils are wound in opposite directions to each other on the third yoke 42 and the sixth yoke 45 (or on the fourth yoke 43 and the fifth yoke 44), and both coils are connected in series. May be.

As a tone wheel, as shown in FIG.
It is also possible to use those having gear-like irregularities formed on the outer peripheral edge as shown in FIG. In this case, the convex portion is the first ferromagnetic portion and the concave portion is the non-magnetic second portion.

[0043]

The rolling bearing unit with a rotation speed detecting device according to the present invention is constructed and operates as described above, but the output of the sensor can be obtained without increasing the width of the rolling bearing unit with a rotation speed detecting device. It can be made large and can reliably detect the wheel rotation speed.

[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 part A in FIG.

FIG. 3 is a view of the tone wheel as viewed from the side of FIG.

FIG. 4 is a perspective view showing the internal structure of the sensor.

FIG. 5 is a plan view of the same.

FIG. 6 is a view similar to FIG. 5, showing a state in which an electromotive force in the opposite direction is generated as the tone wheel rotates.

FIG. 7 is a view similar to FIG. 5, showing a second embodiment of the present invention.

FIG. 8 is a view similar to FIG. 4, showing a third embodiment of the present invention.

FIG. 9 is a view similar to FIG. 6, showing a fourth embodiment of the present invention.

FIG. 10 is a perspective view of an essential part showing a fifth embodiment of the present invention.

FIG. 11 is a view similar to FIG. 3 showing the shape of a tone wheel.

FIG. 12 is a view similar to FIG. 4, showing a sixth embodiment of the present invention.

FIG. 13 is a view similar to FIG. 6, showing a seventh embodiment of the present invention.

FIG. 14 is a sectional view of an essential part showing a first example of a conventional structure.

FIG. 15 is a diagram showing an output signal of a sensor.

FIG. 16 is a sectional view showing a second example of the conventional structure.

FIG. 17 is an enlarged view of a half part viewed from the side of FIG. 16.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 tone wheel 2 unevenness 3 sensor 4 permanent magnet 5 yoke 6 coil 7 controller 8 permanent magnet 9 protrusion 10 yoke 11 bent part 12 coil 12a first coil part 12b second coil part 13 sensor 14 outer ring raceway 15 fixed shaft 16 flange 17 Inner ring raceway 18 Rotating shaft 19 Retainer 20 Rolling element 21 Seal assembly 22 Inner ring 23 Inner seal ring 24 Outer seal ring 25 Space 26 Seal ring 27 Core metal 28 Seal material 29, 29a Tone wheel 30 Tongue piece 31 Cutout 32 Cover 33 Sensor 34 First yoke 34a One end surface 34b Other end surface 35 Second yoke 35a One end surface 35b Other end surface 36 Permanent magnet 37, 37a Coil 38 Synthetic resin 39 Retract part 40 Through hole 41 Sensor 42 Third yoke 43 Fourth York 44 Fifth York 45 Sixth yoke 46 First permanent magnet 47 Second permanent magnet 48 Coil

Claims (3)

[Claims] 1. A fixed wheel that does not rotate during use, a rotary wheel that is provided concentrically with the fixed wheel and that rotates with the wheel during use, and a portion of the peripheral surface of the fixed ring that faces the peripheral surface of the rotary wheel. A first raceway surface formed, a second raceway surface formed on a portion of the peripheral surface of the rotating wheel facing the peripheral surface of the fixed wheel, and provided between the first and second raceway surfaces. A plurality of rolling elements, supported by the rotary wheel, a tone wheel that rotates with the rotary wheel, and a fixed wheel,
A sensor facing the tone wheel is provided, and at least a portion of the tone wheel facing the sensor has a ferromagnetic first portion and a non-magnetic second portion which are alternately arranged in the circumferential direction and the like. It repeats on the pitch,
In the rolling bearing unit with a rotation speed detecting device, each of the sensors is made of a magnetic material and is provided with a plurality of yokes having a total of at least four end faces. At the moment when the end faces of any two of the two faces the first portion, the other two end faces face the second portion, and at least one permanent magnet is provided between the plurality of yokes. Are provided in a state in which both end faces of the permanent magnet in the magnetizing direction are abutted against the respective yokes. Due to the magnetic force of the permanent magnets, a part of the plurality of yokes has end faces of any two of the end faces. Magnetic flux flows alternately between the two end faces and between the two other end faces as the tone wheel rotates. Between the two end faces and the other 2 A coil is wound between the two end faces, and the coil has portions in which the winding directions are opposite to each other with respect to the direction of the magnetic flux that alternately flows. Rolling bearing unit. 2. The sensor comprises first and second yokes, each made of a magnetic material, and both end faces of which face the first and second portions as the tone wheel rotates. The moment the one end surface of the first yoke faces the first portion, the other end surface of the first yoke is the second portion, and the one end surface of the second yoke is the second portion. The other end face of the second yoke faces the first portion, and a permanent magnet is provided between the first yoke and the second yoke, and one end face of the permanent magnet in the magnetization direction is provided. The first yoke is provided with the other end surface in the magnetizing direction abutting the second yoke, respectively, and with a part of the first yoke and a part of the second yoke, Coil is wound in the same direction where the directions of magnetic flux are opposite to each other. The rolling bearing unit with the rotation speed detecting device according to claim 1, wherein 3. The sensor is made of a magnetic material, one end surface of which is opposed to the first and second portions as the tone wheel rotates, and third, fourth, and
The fifth and sixth yokes are provided, and at the moment when one end surfaces of the third and fourth yokes face the first portion, the one end surfaces of the fifth and sixth yokes face the second portion. A first permanent magnet is provided between the third yoke and the fourth yoke, and one end face in the magnetization direction of the first permanent magnet is attached to the third yoke in the magnetization direction. The end faces of the second yoke are attached to the fourth yoke, and a second permanent magnet is provided between the fifth yoke and the sixth yoke. One end in the magnetic direction is provided to the fifth yoke and the other end in the magnetic direction is provided to the sixth yoke, and the one of the third and fourth yokes is provided. A coil is formed in a part of the yoke and a part of one of the fifth and sixth yokes, and a magnetic flux flows through the yoke. It is wound in a direction to be opposite to each other with respect to the direction, speed sensing rolling bearing unit according to claim 1.