JPH07253438A - Roller bearing unit with rotating speed detector - Google Patents

Abstract

PURPOSE:To effectively detect a rotating speed of a wheel synchronized with rotation of a tone wheel by increasing a change of an output signal of a sensor upon rotation of the tone wheel. CONSTITUTION:First and second yokes 34, 35 for forming a sensor 33 are opposed to mutually perpendicular first and second detectors 29, 30 for forming a tone wheel 27 to linearly move. Since a magnetic flux flows through both the detectors 29, 30, an area of a part in which the flux flows is increased, and the flux is scarcely saturated. As a result, a change of the signal of the sensor 33 is increased.

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. 11-12 show the structure described in U.S. 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 by the suspension device side and does not rotate includes a permanent magnet 4 magnetized in the axial direction (vertical direction in FIG. 11), a yoke 5 made of a magnetic material, and wound around the yoke 5. And a coil 6. A base end surface (upper end surface in FIG. 11) of the yoke 5 is abutted against one end surface (lower end surface in FIG. 11) of the permanent magnet 4, and a front end surface (lower end surface in FIG. 11) of the yoke 5 is It opposes the unevenness 2. Therefore, a magnetic field as shown by the broken line in FIG. 11 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. As described above, as the magnetic flux density of the magnetic field formed around the coil 6 changes, the electromotive force induced in the 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, by extracting the electromotive force as an output signal of the sensor 3 and inputting it to the controller 7 of the ABS or TCS, these ABS and TCS can be properly controlled.

[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 sufficiently secure the magnitude (voltage) of the output signal of the sensor 3, Strong magnetic force as the permanent magnet 4 (high magnetic flux density)
You have to use one. 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 magnetic fluxes are divided into systems, the magnetic flux is less likely to be saturated in the yoke 10 as compared with the structure shown in FIG. 11, but it is still difficult to obtain a reliable effect. That is, assuming that the yoke 5 of FIG. 11 and the yoke 10 of FIGS. 13 to 14 have the same cross-sectional area, the structure of FIGS.
The structure shown in can withstand up to about twice the magnetic flux density,
If the permanent magnet 8 having a magnetic flux density exceeding this is used, the magnetic flux is saturated in the yoke 10 as well, and the output of the sensor 13 is extremely reduced.

Also, in the case of the structure shown in FIGS. 13 to 14, all of the magnetic fluxes used for detecting the rotational speed in the tip surface of the permanent magnet 8 and the unevenness 2 formed on the tone wheel 1 are The tip end surface passes through a space between the tip end surface of the convex portion facing the tip end surface. In order to detect the rotational speed with precision, it is necessary to make the pitch of the irregularities 2 fine, and therefore the area of the tip surface of the convex portion and the cross-sectional area of the space are small. Therefore, when the magnetic flux density of the permanent magnet 8 is increased, the magnetic flux is saturated in this space as well, and the sensor 1
The output of 3 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]

A rolling bearing unit with a rotation speed detecting device according to the present invention includes a fixed ring that does not rotate during use and a fixed ring, like the above-described conventional rolling bearing unit with a rotation speed detecting device. A concentric rotating wheel that rotates together with the wheel when in use, and a first raceway surface formed on a portion of the peripheral surface of the fixed wheel that faces the peripheral surface of the rotating wheel,
A second raceway surface formed on a portion of the circumferential surface of the rotating wheel facing the circumferential surface of the fixed wheel; a plurality of rolling elements provided between the first and second raceway surfaces; The tone wheel is supported by a wheel and rotates together with the rotating wheel, and the sensor is supported by the fixed wheel and faces the tone wheel. Then, at least a portion of the tone wheel facing the sensor has a first portion and a second portion having a magnetic characteristic different from that of the first portion alternately and circumferentially repeated at equal pitches. .

Particularly, in the rolling bearing unit with the rotational speed detecting device of the present invention, the tone wheel has a first detecting portion formed in a circular ring shape and a peripheral edge of the first detecting portion formed in a cylindrical shape. From at least one second detection unit continuous with. The first portion and the second portion are formed on the first detection portion and the second detection portion at the same pitch and the same phase. Further, the sensor is a facing member made of a magnetic material, which faces the first and second portions of the first and second detecting portions simultaneously with the rotation of the rotary wheel, the facing member, and the first and second members. The second detection unit includes a permanent magnet arranged in series with respect to the flow direction of the magnetic flux, and a detection unit for detecting the density of the magnetic flux flowing through the facing member.

[0013]

When the rolling bearing unit with the rotational speed detecting device of the present invention constructed as described above is used, when the tone wheel rotates together with the wheels, the facing member faces the first portion of the first and second detecting portions. , The density of the magnetic flux flowing through the facing member is increased. Further, when the facing member faces the second portions of the first and second detecting portions, the density of the magnetic flux flowing through the facing member increases.

Since the facing member simultaneously faces the first and second portions formed on both the first and second detecting portions, the cross-sectional area of the space between the facing member and the first portion is sufficient (see FIG. 11). 1
(More than twice the conventional structure shown in FIG. 4) can be secured. Therefore, at the moment when the facing member faces the first portion and at the moment when the facing member faces the second member, the magnetic flux density flowing through the facing member greatly changes. As a result, the amount of change in the output signal of the detection unit for detecting the magnetic flux density flowing through the facing member can be made sufficiently large.

[0015]

1 to 4 show a first embodiment of the present invention. Double-row outer ring raceways 14, 14 on the inner peripheral surface (first raceway surface)
The fixed ring 15 having the above-mentioned structure can be supported by the suspension device by the flange 24 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. Among these inner ring raceways 17, 17, the inner ring raceway 17 on the inner side (which means the side that becomes the center when assembled to the vehicle, the right side in FIG. 1) is the inner ring that is fitted onto the outer peripheral surface of the inner end portion of the rotating wheel 18. It is formed on the outer peripheral surface of 21. A nut 23 is screwed and tightened to the male screw portion 22 formed on the inner end portion of the rotary wheel 18 while the inner ring 21 is externally fitted, and the inner ring 21 is fixed to the rotary wheel 18.

Then, the outer ring raceway 14 of the fixed ring 15,
14 and the inner ring raceways 17, 17 of the rotary wheel 18, a plurality of rolling elements 2 held by cages 19, 19 respectively.
0 and 20 are provided, and the rotating ring 18 is provided on the inner diameter side of the fixed ring 15.
Is rotatably supported. The outer peripheral surface of the rotating wheel 18 near the outer end (toward the left in FIG. 1) and the outer end of the fixed wheel 15 (the end that becomes the widthwise outer side when assembled to a vehicle, the left end in FIG. 1) A seal ring 39 is provided between the inner ring and the inner surface.
25 in which the rolling elements 20 and 20 are installed
The outer end (left end in FIG. 1) of the portion is closed. In addition, a flange 26 for fixing the wheel is provided at a portion of the outer end portion of the rotary wheel 18 that protrudes from the outer end opening of the fixed wheel 15.
Is provided.

On the other hand, a tone wheel 27 is provided at the inner end portion (the right end portion in FIG. 1) of the inner race 21 at a portion deviated from the inner raceway 17. This tone wheel 27
Has a crank-shaped cross section and is formed into an annular shape by pressing a magnetic metal plate. The tone wheel 27 includes a support cylinder portion 28 for externally fitting and fixing to the inner end portion of the inner ring 21, and a circular ring-shaped first detection bent outward in the diametrical direction from the inner end edge of the support cylinder portion 28. Part 29,
The first detection unit 29 is provided with a cylindrical second detection unit 30 that is continuous from the outer peripheral edge toward the inside.

The first and second detectors 29 and 30 include
A large number of through holes 31, 31 each formed in a rectangle,
They are formed at equal intervals in the circumferential direction. Of the first and second detection units 29 and 30, the portion between the adjacent through holes 31 and 31 is a ferromagnetic first portion, and each of the through holes 31 and 31 is a nonmagnetic second portion. The first portion and the second portion are formed on the first and second detection units 29 and 30 at the same pitch and the same phase.

A cover 32 is fitted in and fixed to the inner end opening (the right end opening in FIG. 1) of the fixed wheel 15. The cover 32 is formed into a bottomed cylindrical shape by drawing a metal plate. The sensor 33 supported and fixed inside the cover 32 is attached to the tone wheel 27.
The inner surface of the first detection unit 29 and the second detection unit 30 that configure the
Is opposed to the inner peripheral surface of the via a minute gap.

This sensor 33, as shown in FIGS.
First and second yokes 34, 3 which are opposing members, respectively
5, the permanent magnets 36 and 36, and the coil 37 that is the detection unit
And are serially combined in the axial direction of the coil 37 (vertical direction in FIG. 4). The combination order is such that the coil 37 is located at the center and the permanent magnets 36, 36 are located at both ends. Of these, the first and second yokes 34, 3
Each of 5 is made of a magnetic material in a flat plate shape.
The outer end surface and the upper end surface of the first and second yokes 34, 35 face the inner side surface of the first detection section 29 and the inner peripheral surface of the second detection section 30 with a minute gap therebetween. There is.
Then, each of these end faces alternates with the through holes 31 and 31 formed in the first and second detecting portions 29 and 30 or between the adjacent through holes 31 and 31 as the tone wheel 27 rotates. opposite.

The permanent magnets 36, 36 are magnetized in the axial direction of the coil 37, and the magnetizing directions are opposite to each other. Further, the coil 37 is
It is wound around an iron core 38 spanned between the second yokes 34, 35 and generates an output signal according to the amount of change in the magnetic flux flowing inside the iron core 38. The magnitude (voltage) of the output signal generated in this manner is determined by the rotation wheel 1
The frequency of the output signal is proportional to the rotation speed of the rotating wheel, although it changes with the rotation of 8. Therefore, if this output signal is sent to a controller (not shown), it is possible to know the rotational speed of the wheels that rotate together with the rotary wheel 18.

In this case, the opposing member, first,
The second yokes 34 and 35 are the first and second detection units 29 and 30.
And the through holes 31, 31 formed in both of them, or a portion therebetween is simultaneously opposed. Therefore, the first and second yokes 34,
A sufficient cross-sectional area of the space between 35 and the above-mentioned portion can be secured. Therefore, the magnetic flux density flowing through the first and second yokes 34 and 35 at the moment when the first and second yokes 34 and 35 face the interspace and at the moment when they face the through holes 31 and 31. Changes greatly. As a result, the amount of change in the output signal of the coil 37 can be made sufficiently large.

In particular, in the illustrated embodiment, the first yoke 3
4 and the second yoke 3 at the moment when the holes 4 and 31 face each other.
5 is shifted from the moment when the through holes 31 and 31 face each other, and the phases are opposite to each other. Further, the pair of permanent magnets 36, 36 are magnetized in opposite directions. Therefore, with the rotation of the tone wheel 27, magnetic fluxes in opposite directions alternately flow through the iron core 38. As a result, the amount of change in the output signal can be increased.

The respective members 34, 3 constituting the sensor 33 are
The arrangement order of 5, 36 and 37 is not limited to that shown in FIGS. For example, the first and second yokes 34, 35
The permanent magnet 36 and the coil 37 can be sandwiched between the two yokes 34, 35 by arranging the both ends. In this case, the first and second yokes 34 and 35 are simultaneously formed in the through hole 3
The distance between the two yokes 34, 35 is regulated so as to face the first and the third holes 31 (or the portions between the adjacent through holes 31, 31). In this case, one permanent magnet 36 is sufficient. When two or more magnets are provided, the magnetizing directions are matched.

With this structure, both yokes 34 and 35 are formed.
The magnetic flux density in the iron core 38 of the coil 37 becomes low at the moment when is opposed to the through holes 31, 31, and the magnetic flux density becomes high at the moment when it is opposed to the gap portion. Then, an electromotive force is generated in the coil 37 according to the change in the magnetic flux density.

Next, FIG. 5 shows a second embodiment of the present invention. In this embodiment, the tone wheel 27a is formed by casting, forging, or shaving a magnetic material into an annular shape. Then, the inner side surface of the circular ring-shaped first detection unit 29a and the cylindrical second detection unit 30.
Irregularities are formed on the outer peripheral surface of a in the circumferential direction. The convex portion of the unevenness corresponds to the first ferromagnetic portion, and the concave portion corresponds to the second weak magnetic portion.

In the case of this embodiment, the opposing portion of the sensor 33a is the inner surface of the first detecting portion 29a and the second detecting portion 3a.
It faces the outer peripheral surface of 0a through a minute gap, respectively. Other configurations and operations are similar to those of the above-described first embodiment.

Next, FIGS. 6 to 7 show a third embodiment of the present invention. The structure shown in FIG.
While the present invention is applied to the rolling bearing unit for supporting the front wheels of the vehicle and the rear wheels of the FF vehicle, in the case of this embodiment, the drive wheels (the rear wheels of the FR vehicle and the FF vehicle). The present invention is applied to the front wheel). Therefore, in the case of the present embodiment, the rotary wheel 18a is formed in a hollow cylindrical shape, and
A spline groove is formed on the inner peripheral surface of 8a. An annular cover 32a is externally fitted and fixed to the inner end opening of the fixed wheel 15, and the sensor 33 is supported by a part of the cover 32a. Further, the seal ring 39 is also provided on the inner end of the fixed ring 15.
a is fitted inside. Other configurations and operations are similar to those of the first embodiment described above.

Next, FIG. 8 shows a fourth embodiment of the present invention. In the case of this embodiment, the tone wheel 2 of the second embodiment shown in FIG. 6 is added to the structure of the third embodiment described above.
7a and the sensor 33a are combined. Other configurations and operations are the same as those of the second embodiment or the third embodiment described above.

Next, FIG. 9 shows a fifth embodiment of the present invention. In the case of the present embodiment, one first detection unit 29a and two second detection units 30 are used as the tone wheel 27b.
A and 30b each having a U-shaped cross section and formed in an annular shape as a whole are used. A permanent magnet 36 is attached to the inner end surface of a pole piece 40, which is a facing member constituting the sensor 33b, and a coil 37 is wound around the outer peripheral surface of the middle portion of the pole piece 40. And the pole piece 40
The inner end portion of the first detecting portion 29a, the outer peripheral surface of the one second detecting portion 30a, and the other second detecting portion 30b.
And the inner peripheral surface of each of them through a minute gap.

Also in the case of the present embodiment, the detection units 29a and 30 are provided.
The irregularities formed on a and 30b and the inner end surface of the pole piece 40 face each other in the same phase. Other configurations and operations are the same as those in the above-described embodiments.

Next, FIG. 10 shows a sixth embodiment of the present invention. In the case of this embodiment, inside the tone wheel 27b similar to that incorporated in the above-mentioned fifth embodiment,
The U-shaped yoke 41, which is a facing member that constitutes the sensor 33c, is inserted with the U-shaped opening facing outward. The upper surface of the yoke 41 faces the lower surface of the one second detecting portion 30a, and the lower surface faces the upper surface of the other second detecting portion 30b with a minute gap therebetween.

Inside the yoke 41, a permanent magnet 36 and a Hall element 42, which are magnetized in the inner and outer directions (left and right directions in FIG. 10), are arranged in series in the magnetizing direction. is doing. Then, the outer end surface of the Hall element 42 is
It faces the inner surface of the first detection unit 29a with a minute gap.

In the case of this embodiment, the tone wheel 27 is used.
With the rotation of b, the density of the magnetic flux passing through the Hall element 42 changes, and the output signal of the sensor 33c incorporating the Hall element 42 changes. Other configurations and operations are the same as those in the above-described embodiments.

[0035]

The rolling bearing unit with a rotation speed detecting device of the present invention is constructed and operates as described above, but the output of the sensor can be increased without increasing the size of the rolling bearing unit with a rotation speed detecting device. Therefore, 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 part A in FIG.

FIG. 3 is a perspective view of a sensor.

FIG. 4 shows a positional relationship between a tone wheel and a sensor,
FIG. 3 is a view corresponding to a BB cross section of FIG. 2.

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

FIG. 6 is a sectional view showing a third embodiment of the present invention.

FIG. 7 is an enlarged view of part C in FIG.

FIG. 8 is a view similar to FIG. 7, showing a fourth embodiment of the present invention.

FIG. 9 is a view showing a fifth embodiment of the present invention, in which the tone wheel and the constituent members of the sensor are viewed from the same direction as FIG.

FIG. 10 is a view similar to FIG. 9 showing a sixth embodiment of the present invention.

FIG. 11 is a sectional view of an essential part showing a first example of a conventional structure.

FIG. 12 is a diagram showing an output signal of a sensor.

FIG. 13 is a cross-sectional view showing a second example of the conventional structure.

FIG. 14 is an enlarged view of a half part as viewed from the right side (inside) of FIG.

[Explanation of symbols]

 1 Tone Wheel 2 Unevenness 3 Sensor 4 Permanent Magnet 5 Yoke 6 Coil 7 Controller 8 Permanent Magnet 9 Projection 10 Yoke 11 Bend Part 12 Coil 12a First Coil Part 12b Second Coil Part 13 Sensor 14 Outer Ring Track 15 Inner Ring 17 Tracks 18 and 18a Rotating wheel 19 Retainer 20 Rolling element 21 Inner ring 22 Male screw part 23 Nut 24 Flange 25 Space 26 Flange 27, 27a, 27b Tone wheel 28 Support cylinder part 29, 29a First detecting part 30, 30a, 30b Second Detection unit 31 Through hole 32, 32a Cover 33, 33a, 33b, 33c Sensor 34 First yoke 35 Second yoke 36 Permanent magnet 37 Coil 38 Iron core 39, 39a Seal ring 40 Pole piece 41 Yoke 42 Hall element

Claims (1)

[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 first portion and a second portion having a magnetic characteristic different from that of the first portion alternated in the circumferential direction. In the rolling bearing unit with a rotation speed detecting device, which repeats at an equal pitch, the tone wheel has a ring-shaped first detecting portion and a cylindrically-shaped first detecting portion. Continuing from the periphery, at least one second detection unit, and the first detection unit and the second detection unit, the first portion and the second portion are formed at the same pitch and the same phase, The sensor includes a facing member made of a magnetic material, which faces the first and second portions of the first and second detectors simultaneously with the rotation of the rotary wheel, and the facing member and the first and second members. Flow of magnetic flux to the detector A permanent magnet arranged in series with respect to the direction, speed sensing rolling bearing unit and a detection unit for detecting a density of magnetic flux flowing through the opposing member.