JPH10132837A - Rolling bearing unit with rotational speed detecting equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a structure wherein the output of a sensor can be sufficiently ensured without enlarging the dimension. SOLUTION: A through hole 35 and a pillar part are formed on a second cylindrical part 34 of tone wheel 31 which rotates together with a rotating wheel 1a. Comb teeth type end edge parts formed on both end endge parts of a stator 42 constituting a sensor 38 are made to face the second cylindrical part 34. Same poles of a pair of permanent magnets 45, 45 are made to abut against each other at both end parts of the stator 42, one side pole which is not made to abut is arranged adjacently to a flange part 33 of tone wheel 31, and the other side pole is arranged adjacently to a cover 37 formed of magnetic material. The sensor 38, tone wheel 31 and the cover 37 constitute a closed loop magnetic circuit.

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 anti-lock brake system (ABS) or a traction control system (TCS) to detect a rotation speed of a wheel of an automobile. Use it for

[0002]

2. Description of the Related Art In order to control an anti-lock brake system (ABS) or a traction control system (TCS) of a vehicle, it is necessary to detect a rotation speed of a wheel. Various types of rolling bearing units with a rotation speed detecting device for this purpose have been conventionally known, for example, as described in JP-A-8-15290.

FIGS. 5 to 7 show a rolling bearing unit with a rotation speed detecting device described in this publication. The rolling bearing unit with the rotation speed detecting device includes a rotating wheel 1,
Fixed wheel 2, a plurality of rolling elements 3, 3, and tone wheel 4
And a sensor 5. The rotating wheel 1 has an inner ring 6 fitted and fixed to an inner end portion (right end portion in FIG. 5), and has inner ring raceways 7 on the outer peripheral surfaces of the rotating wheel 1 and the inner ring 6, so that the rotating ring 1 can be used. Rotate. Further, the fixed wheel 2 has outer raceways 8, 8 on an inner peripheral surface facing the outer peripheral surface, and does not rotate during use. Further, the plurality of rolling elements 3, 3 are provided between the inner raceways 7, 7 and the outer raceways 8, 8, respectively.
The rotating wheel 1 is rotatably supported inside the fixed wheel 2 by being provided so as to be freely rotatable while being held by 8 and 18. The sensor 5 is provided at the inner end of the fixed wheel 2 (FIG. 5).
At the right end of the cover 10).

A seal assembly 19 is mounted between the inner peripheral surface of the inner end of the rotating wheel 1 and the inner peripheral surface of the fixed wheel 2.
The inner end opening of the space 20 where the rolling elements 3 and 3 are installed is closed. The seal assembly 19 includes an inner seal ring 21 externally fixed to the shoulder of the inner ring 6 externally fixed to the rotating wheel 1, and an outer seal ring 22 internally fixed to the inner end of the fixed ring 2. Consists of The outer end opening of the space 20 is
It is closed by another seal ring 23.

[0005] The inner seal ring 21 includes a core metal 24 and a seal material 25. The tone wheel 4 is provided on the inner side surface (the right side surface in FIG. 5) of the metal core 24. The tone wheel 4 is formed in an annular shape from a magnetic material such as a steel plate, and has a large number of through holes 9, 9 or notches formed in the circumferential direction at an equal pitch, and is concentric with the rotating wheel 1. Has been placed.

As shown in FIGS. 6 and 7, the sensor 5 has a stator 11 made of a magnetic material and entirely formed in a rectangular shape.
And a coil 12 formed by winding a conductive wire around an intermediate portion of the stator 11, and a pair of permanent magnets 13, 1
3 Both end surfaces 14, 15 of the stator 11
Is a part of the tone wheel 4, the large number of through holes 9,
The portion 9 is opposed to the portion formed with a small gap. At the moment when one end face 14 (15) of the stator 11 faces the through hole 9, the other end face 15 (14) faces the column portion 16 existing between the adjacent through holes 9. The gap between both end surfaces 14 and 15 of the stator 11 is regulated.

As shown in FIG. 7, an alternating magnetic flux flows through the stator 11 of the sensor 5 configured as described above as the tone wheel 4 rotates together with the rotating wheel 1. That is, as shown in FIG. 7A, when one end face 14 of the stator 11 faces the column portion 16, the other end face 15 faces the through-hole 9, and the magnetic flux passes through the inside of the stator 11. It flows in the direction indicated by the arrow in FIG. In contrast, FIG.
As shown in (B), when one end face 14 of the stator 11 faces the through hole 9, the other end face 15 is connected to the column portion 1.
6, the magnetic flux flows through the inside of the stator 11 in a direction indicated by an arrow in FIG. And, corresponding to this alternating magnetic flux,
A voltage in the opposite direction is generated alternately in the coil 12 provided in the intermediate portion of the stator 11. The frequency at which this voltage changes is proportional to the rotation speed of the tone wheel 4. Therefore, the voltage induced in the coil 12 is applied to the sensor 5
As an output signal of the above, the ABS or TCS can be controlled by extracting it from the conductor 17 provided on the cover 10 and sending it to the controller of the ABS or TCS.

[0008]

The structure described and described in Japanese Patent Application Laid-Open No. H8-15290, which is constructed and operates as described above, enables a large output to be obtained despite a relatively small structure. However, with the spread of ABS and TCS in recent years, it is desired to realize a structure capable of obtaining a larger output in order to reduce the cost of these ABS and TCS controllers while ensuring the reliability of these ABS and TCS. It is rare.

That is, the electromotive force generated in the coil 12 of the sensor 5 is determined by the amount of change in the magnetic flux flowing through the intermediate portion of the stator 11. However, the stator 11 does not
Due to the limited mounting space, it cannot be too large.
Therefore, the amount of change in the magnetic flux cannot be too large.
In order to increase the amount of change in the magnetic flux, the permanent magnet 1
Although it is conceivable to increase the magnetic force of the coils 3 and 13 (increase the magnetic flux density), the magnetic flux flowing in the stator 11 tends to be saturated if the cross-sectional area of the stator 11 cannot be increased. When the magnetic flux is saturated, the amount of change in the magnetic flux according to the rotation speed of the wheel becomes extremely small, and the electromotive force generated in the coil 12 becomes extremely small. The rolling bearing unit with a rotation speed detecting device of the present invention was invented in view of such circumstances.

[0010]

A rolling bearing unit with a rotation speed detecting device according to the present invention is supported on a fixed wheel which does not rotate during use, similarly to a conventionally known rolling bearing unit with a rotation speed detecting device. A sensor and a tone wheel provided concentrically with the fixed wheel, supported by a rotating wheel that rotates during use, and rotated with the rotating wheel. At least a portion of the tone wheel facing the sensor has a first portion (e.g., a thinned portion such as a notch, a through hole, and a concave portion) and a second portion (e.g., a column, a protrusion, Magnetic parts such as protrusions) are arranged alternately and at equal pitches in the circumferential direction. In particular, in the rolling bearing unit with a rotation speed detecting device of the present invention, a magnetic material is supported on a part of the fixed wheel, and the magnetic material is provided on at least a part of the tone wheel on a side opposite to the sensor. It faces the position and a part of the sensor. Further, the tone wheel has a first cylindrical portion supported by an end of the rotating wheel, a flange bent in a diametrical direction from an end of the first cylindrical portion, and an end of the flange. A second cylindrical portion extending in the axial direction. The second cylindrical portion is concentric with the first cylindrical portion. In addition, the sensor includes an annular stator arranged concentrically with the tone wheel, and the same poles are abutted or brought close to both ends of the stator. A pair of permanent magnets and a coil wound around an intermediate portion of the stator, each of which is in close proximity to a part of the tone wheel or a part of the magnetic material. Then, a plurality of projections and notches are provided at both end portions of the stator alternately in the circumferential direction and at the same pitch as the first portion and the second portion provided on the tone wheel, respectively. A comb-like edge is formed. Further, at the moment when each protruding portion forming one comb tooth edge portion faces the first portion, each protruding portion forming the other comb tooth edge portion faces the second portion, and The sensor, the tone wheel and the magnetic material constitute a closed loop magnetic circuit.

[0011]

In the case of the rolling bearing unit with the rotation speed detecting device of the present invention configured as described above, when the tone wheel rotates together with the rotating wheel, each comb-shaped edge formed at both ends of the stator is formed. The moment when each of the plurality of protrusions faces the first portion of the tone wheel,
Alters alternately. That is, at a certain moment, the protrusion at one end of the stator faces the first portion, and the protrusion at the other end faces the second portion of the tone wheel. Then, at the next moment, the protruding portion of one end edge of the stator faces the second portion, and the protruding portion of the other end portion faces the first portion. In this way, at the moment when the protruding portion of the one end edge of the stator faces the first portion and the protruding portion of the other end edge faces the second portion, respectively, At the moment when the protruding portion of the other end edge portion is opposed to the first portion, the magnetic flux flows in the stator in opposite directions. Accordingly, an alternating magnetic flux flows in the stator as the rotating wheel rotates. Then, in accordance with the alternating magnetic flux flowing through the inside of the stator, an electromotive force is generated in the coil alternately in the opposite direction.
For this reason, the difference between the highest value and the lowest value of the voltage can be increased,
The accuracy of rotation speed detection can be improved.

In particular, in the case of the rolling bearing unit with the rotation speed detecting device of the present invention, the sensor is formed in a ring shape, and the magnetic flux is less likely to be saturated by increasing the sectional area of the stator constituting the sensor. . Also, the amount of magnetic flux flowing in the stator along the coil constituting this sensor is:
It is the sum of the magnetic flux flowing through each comb-shaped edge formed over the entire circumference. Therefore, the electromotive force generated in this coil can be further increased. Further, a magnetic material is supported on a part of the fixed wheel, and the magnetic material is positioned at least on a part of the tone wheel on a side opposite to the sensor and on a part of the sensor. And a magnetic material constitute a closed loop magnetic circuit. Therefore, the magnetic flux
On both sides of the coil, the current flows over the entire circumference. Therefore, the electromotive force generated in this coil can be further increased, and the accuracy of rotation speed detection can be sufficiently improved.

[0013]

1 to 3 show a first embodiment of the present invention corresponding to claim 1. FIG. In this embodiment, the present invention is applied to a rolling bearing unit for supporting non-drive wheels (a front wheel of an FR vehicle, a rear wheel of an FF vehicle). Double rows of outer raceways 8, 8 are formed on the inner peripheral surface of the fixed wheel 2a that does not rotate during use. This fixed wheel 2a
Can be supported on a suspension device by a flange 26 formed on the outer peripheral surface thereof. Inside the fixed wheel 2a,
A rotating wheel 1a that rotates during use is arranged. An inner ring 6a is externally fitted and fixed to the inner end (the right end in FIG. 1) of the rotating wheel 1a, and inner ring tracks 7, 7 are formed on the outer peripheral surfaces of the rotating wheel 1a and the inner ring 6a, respectively. Orbit 7, 7
Are opposed to the outer ring raceways 8, 8. And
Between each of these outer raceways 8, 8 and each of the inner raceways 7, 7,
A plurality of rolling elements 3, 3 held by retainers 18, 18, respectively, are provided, and a rotating wheel 1a is provided inside the fixed wheel 2a.
Is rotatably supported. A flange 27 for fixing a wheel to the rotating wheel 1a is provided in a portion near the outer end of the outer peripheral surface of the rotating wheel 1a and protruding from an outer end opening of the fixed wheel 2a. A nut 29 is screwed and tightened onto a male screw portion 28 formed at the inner end of the rotating wheel 1a while the inner ring 6a is externally fitted to the inner end of the rotating wheel 1a to rotate the inner ring 6a. It is fixed to the wheel 1a.
A seal ring 23a is provided between the outer peripheral surface of the rotating wheel 1a (left end in FIG. 1) and the inner peripheral surface of the outer end of the fixed wheel 2a.
To close the outer end opening of the space 30 where the rolling elements 3 and 3 are installed.

A tone wheel 31 is externally fixed to a portion of the inner end of the inner ring 6a which is off the inner ring raceway. The tone wheel 31 has a first cylindrical portion 32 formed into a cylindrical shape by press-forming a magnetic metal plate such as a mild steel plate, and diametrically outward from an end of the first cylindrical portion 32. It comprises a bent flange portion 33 and a second cylindrical portion 34 extending in the axial direction from the end of the flange portion 33 and present around the nut 29. In the second cylindrical portion 34, a rectangular through hole 35 which is a first portion and which is long in the axial direction is alternately and equally pitched in the circumferential direction.
And a plurality of pillar portions 36 (FIG. 3) existing between the adjacent through holes 35 in the second portion.

On the other hand, at the inner end opening of the fixed wheel 2a,
An open end of a bottomed cylindrical cover 37 formed by subjecting a magnetic metal plate such as a mild steel plate to plastic working such as drawing is externally fitted and fixed, and the inner end opening of the fixed ring 2a is closed. And
In this cover 37, an annular synthetic resin 39 in which a sensor 38 is embedded is held and fixed. The sensor 38 is made of a magnetic metal plate such as a mild steel plate, and includes a stator 42 formed by combining first and second stator elements 40 and 41 arranged in series with each other with respect to the flow direction of magnetic flux.
A coil 44 formed by winding a wire around a bobbin 43;
It comprises a pair of permanent magnets 45, 45. In this case,
The constituent members of the sensor 38 are all formed in an annular shape.

The first stator element 40 has one end edge (the left end edge in FIGS. 1 to 3) of the cylindrical portion folded back outward in the diametrical direction to have a U-shaped cross section, and a first half of the folded portion. In a portion facing the inner peripheral surface of the second cylindrical portion 34,
A first comb-shaped edge 46 is formed. The first comb-shaped edge portion 46 has a plurality of projections 47, 4 respectively.
7 and the notches 48, 48 are alternately provided at equal pitches in the circumferential direction, and the whole is in a comb shape. And these projections 47, 47 and notches 48, 48
And the center angle pitch of the through hole 35 and the column portion 36 formed in the second cylindrical portion 34 are made equal to each other. Therefore, at the moment when all the protruding portions 47 face the through holes 35 (or the pillar portions 36), all the notches 48, 48 are in the column portions 36 (or the through holes 35).
Oppose. Further, the shape of the other end of the cylindrical portion of the first stator element 40 (the right end in FIGS. 1 to 3) extending in the circumferential direction is simply a straight line.

On the other hand, the second stator element 41 has a U-shaped cross section. Then, the other end edge of the cylindrical portion of the first stator element 40 is brought into contact with or close to the outer surface of the second stator element 41, and one end of the first and second stator elements 40, 41. The parts are fitted to each other by interference fit in the radial direction, and the first and second stator elements 40 and 41 are magnetically connected to each other to form a stator 42. In addition, the second comb-shaped edge 4 is provided on the outer peripheral edge of the second stator element 41.
9 are formed. Like the first comb-shaped edge 46, the second comb-shaped edge 49 also includes a plurality of projections 47, 47 and cutouts 48, 48, respectively. The through holes 35 and the column portions 36 formed in the cylindrical portion 34 are formed at the same pitch as the center angle pitch. However, the phase of the second comb-shaped edge 49 and the phase of the first comb-shaped edge 46 are shifted from each other by a half pitch. That is, the projections 47, 47 (or the notches 48, 48) constituting the second comb-toothed edge 49 are formed in the through holes 3
At the moment opposed to 5, the protrusions 47, 47 (or notches 48, 48) constituting the first comb-shaped edge 46 are formed.
Faces the column portion 36.

As described above, the structure in which the first and second stator elements 41 are partially overlapped in the radial direction and fitted to each other secures the axial length (contact area) of the overlapping portion. As a result, these first and second stator elements 4
The magnetic resistance of the divisional connection between 0 and 41 can be reduced. Further, if the bent portion on the inner diameter side of the second stator element 41, which is a small diameter portion of the overlapping portion, is shifted from the hexagonal column portion of the nut 29, interference between the hexagonal column portion and the bent portion is prevented. As a result, limited space can be effectively used. On the other hand, it is also possible to adopt a structure in which the inner diameters of the first and second stator elements 40 and 41 are made the same, and the edges of the two stator elements 40 and 41 abut against each other. However, if such a structure is adopted, in order to secure the contact area between the two stator elements 40 and 41 and to reduce the magnetic resistance of the split connection portion, it is necessary to use the magnetic material forming the two stator elements 40 and 41. The thickness of the metal plate must be increased. For this reason, bending of the magnetic metal plate becomes difficult, or the capacity of the two stator elements 40 and 41 is increased, and the degree of freedom in design is lost. Therefore, it is preferable as a means for suppressing the magnetic resistance to be small. Absent.

The coil 44 is installed at a portion surrounded by the first and second stator elements 40 and 41 on three sides except the outer peripheral side. That is, these two stator elements 40 and 41 enclose a bobbin 43 having a U-shaped cross section, which is open outward in the diameter direction. Then, a wire is wound around the bobbin 43 to form the coil 44. The first and second comb-shaped edge portions 46, 4 formed on the first and second stator elements 40, 41, respectively.
In order to shift the phase of each other by a half pitch as described above, the bobbin 43 and the first and second stator elements 40,
An uneven engaging portion can be formed between the 41. For example, if engaging projections are formed on both end surfaces in the axial direction of the bobbin 43, and the first and second stator elements 40 and 41 are formed with engaging holes for fitting these engaging projections, The phase between the first and second comb-like edge portions 46 and 49 can be reliably regulated.

Further, the first and second stator elements 4
0, 41, in the axial direction of the sensor 38 (FIGS. 1 to 3).
Permanent magnets 45, 45 are respectively abutted against surfaces opposite to the coil 44, which correspond to both end surfaces. Each of these permanent magnets 45 is formed in an annular shape, and is magnetized in the axial direction. These permanent magnets 4
The magnetizing directions of the magnets 5 and 45 are opposite to each other, and the permanent magnets 45 and 45 face each other with the same polarity.
Incidentally, these permanent magnets 45, 45 can be combined with a plurality of elements formed in an arc shape and formed in an annular or partially annular shape to reduce the cost.

With the cover 37 supporting the above-described sensor 38 via a synthetic resin 39 fitted and fixed to the inner end opening of the fixed wheel 2a, the first stator element 4
0 and the second comb-shaped edge 49 of the second stator element 41 are provided on the inner peripheral surface of the second cylindrical portion 34 with minute clearances, respectively. They face each other through 50. Also, one of the two permanent magnets 45 (FIG. 1)
The left (up to 3 left) permanent magnets 45 are surfaces (poles) opposite to the surfaces (poles) that abut against the first stator element 40.
Is replaced with a flange portion 33 constituting the tone wheel 31.
Close to. The other permanent magnet 45 (right side in FIGS. 1 to 3) of the two permanent magnets 45, 45 is a surface (pole) opposite to a surface (pole) abutting on the second stator element 41. ) Is brought close to one side surface of the bottom of the cover 37 made of a magnetic material.

In the case of the rolling bearing unit with the rotation speed detecting device of the present invention configured as described above, when the second cylindrical portion 34 constituting the tone wheel 31 rotates together with the rotating wheel 1a, one end of the stator 42 is rotated. The through-holes 35 and the column portions 36 facing the protruding portions 47, 47 of the first comb-shaped edge portion 46 located at the edge portion, and the second comb-shaped portion also located at the other end edge portion of the stator 42 Projections 47, 4 of edge 49
The through-hole 35 and the column portion 36 facing 7 alternately change. That is, at a certain moment, as shown in FIG. 3 (A), the projection 47 of the first comb-shaped edge 46 is attached to the column 36, and the projection of the second comb-shaped edge 49. 47 is a through hole 35 (FIG. 2)
, Respectively. And at the next moment,
As shown in (B), the protrusions 4 of the first comb-shaped edge 46 are formed.
7 faces the through hole 35 (FIG. 2), and the protruding portion 47 of the second comb-like edge portion 49 faces the column portion 36.

In this embodiment, as shown in FIG. 3, the N poles of the permanent magnets 45 are opposed to each other. Therefore, as shown in FIG. 3A, the projection 47 of the first comb-shaped edge 46 is provided in the column 36, and the projection 47 of the second comb-shaped edge 49 is provided in the through hole 35. At the moment when they face each other,
In the cylindrical portion of the first stator element 40, as shown by an arrow in FIG.
A magnetic flux flows from right to left in (A). On the other hand, as shown in FIG. 3B, the protrusion 47 of the first comb-like edge 46 is provided in the through hole 35 and the protrusion 4 of the second comb-like edge 49.
At the moment when each 7 faces the column portion 36, a magnetic flux (from left to right in FIG. 3B) flows from one end to the other end in the cylindrical portion. Therefore, an alternating magnetic flux flows in the cylindrical portion as the rotating wheel 1a rotates. Accordingly, a voltage in the opposite direction is induced in the coil 44 alternately in accordance with the alternating magnetic flux.

The frequency at which the voltage generated in the coil 44 changes as described above is proportional to the rotation speed of the tone wheel 31. Therefore, the voltage induced in the coil 44 is extracted by a harness (not shown) through a connector 51 provided on a part of the cover 37, and the voltage is applied to the ABS or TC.
If the signal is sent to a controller that controls S, the ABS and TCS can be appropriately controlled.

In the case of the rolling bearing unit with the rotation speed detecting device of the present invention, the sensor 38 is formed in an annular shape as described above, and the sectional area of the stator 42 constituting the sensor 38 is increased. The magnetic flux is less likely to saturate in the region. The coil 44 constituting the sensor 38
Is the sum of the magnetic fluxes flowing through the comb-shaped edge portions 46 and 49 formed over the entire circumference. Therefore, the electromotive force generated in the coil 44 can be increased in any direction. As a result, the difference between the maximum value and the minimum value of the voltage can be increased, and the accuracy of rotation speed detection can be improved.

Further, in the case of the rolling bearing unit with the rotation speed detecting device of the present invention, this coil 44
Can be increased. That is, FIG.
At the moment shown in (A), the magnetic flux flowing from the first comb-shaped edge portion 46 to the column portion 36 further flows inside the cover 37 made of the magnetic material from one end to the other end. . On the other hand, at the moment shown in FIG. 3B, the magnetic flux flowing from the second comb-shaped edge portion 49 toward the column portion 36 further moves the column portion 36 from the other end to one end. Flows towards In this way, the sensor 38, the tone wheel 31, and the magnetic material constitute a closed loop magnetic circuit, so that a large amount of magnetic flux flows not only inside the coil 44 but also outside the coil 44 over the entire circumference. become. Therefore, the electromotive force generated in the coil 44 can be further increased. Thereby, the difference between the maximum value and the minimum value of the voltage can be further increased, and the accuracy of rotation speed detection can be sufficiently improved. It should be noted that even if the cover 37 is made of a non-magnetic material, in other words, even if the magnetic material facing a part of the tone wheel opposite to the sensor and a part of the sensor is omitted (the output is higher than the illustrated example). Although it is lower), a larger output than before can be obtained.

Next, FIG. 4 shows a second embodiment of the present invention corresponding to claim 2. In this example, the structure of the stator constituting the structure of the above-described first example is changed from the first example. That is, the first stator element 40a and the second stator element 41a constituting the stator 42a
In the circumferential direction, half of the comb-tooth-shaped edge portions provided at both edge portions are all cutouts 48a, 48a. That is, the first and second stator elements 40a, 41a are not formed with protrusions in the lower halves, but are provided with only the cutouts 48a, 48a. In the remaining upper half, a plurality of projections 47 and notches 48 are respectively provided on the first stator element 40a and the second stator element 41a in the circumferential direction, similarly to the structure of the first example. The first stator element 40 is provided so as to be alternately provided at equal pitches and to shift the projections 47 and the notches 48 from each other by a half pitch.
a and the second stator element 41a.
Further, similarly to the structure of the first example, the center angle pitch of the protruding portion 47 and the notch 48, the through-hole 35 and the column portion 36 formed in the second cylindrical portion 34 of the tone wheel 31 are formed.
Are made equal to each other. Other structures are the same as in the first example.

In the case of the rolling bearing unit with the rotation speed detecting device of the present embodiment configured as described above, the second cylindrical portion 34 forming the tone wheel 31 rotates together with the rotating wheel 1a, and the rotation of the rotating wheel 1a. A reverse voltage is induced in the coil 44 alternately in proportion to the speed. The frequency at which this voltage changes changes in proportion to the rotation speed of the rotating wheel 1a as in the case of the first example. The magnitude of this voltage is constant when the car travels on a flat road, but when the axis of the rotating wheel 1a is slightly displaced due to the car traveling on a bad road, etc. Voltage magnitude is not constant. That is, in the case of the structure of the first example, the protruding portions 47 and the notches 48 of the comb-teeth-shaped edge portions provided at both end portions constituting the stator 42a constituting the sensor 38 are formed over the entire circumference. Had formed. For this reason, even if the minute gap 50 between the tone wheel 31 and the stator 42a changes due to the slight displacement of the axis of the rotating wheel 1a in the diameter direction, the magnitude of the voltage changes accordingly. There are few things. That is,
The voltage increases when the minute gap 50 decreases, and decreases when the minute gap increases. However, in the case of the first example described above, if the minute gap 50 becomes large in a part in the circumferential direction, it becomes small in other parts. Therefore, the change in the voltage is offset in the circumferential direction of the stator 42a. Therefore, as a result, the coil 4
The magnitude of the voltage generated at 4 is kept constant. On the other hand, in the case of the present example, since the lower half of the comb-tooth-shaped edge of the stator 42a has only the cutouts 48, 48, when the axis of the rotating wheel 1a is displaced in the diametrical direction, the voltage becomes lower. Size is not kept constant. Therefore, if the degree of the voltage change is sent to a controller (not shown) through the connector 51, the condition of the road surface can be determined. Then, for example, the damping force of the damper of the suspension system of the vehicle is appropriately adjusted based on this determination, so that a comfortable ride comfort can be given to the occupant, or traveling safety can be ensured.

In both the first and second examples described above, the cover 37 is made of a magnetic material to provide a magnetic material. However, the cover 37 is not made of a magnetic material and is different from the cover 38. May be supported and fixed to the fixed wheel 1a. For example, a magnetic metal plate having an L-shaped cross section and formed in an annular shape as a whole is embedded in a synthetic resin 39, and the metal plate is used as an outer peripheral surface of a second cylindrical portion 34 of the tone wheel 31 and one permanent magnet. 45
To the other pole (right side in FIGS. 1 to 4).

[0030]

Since the rolling bearing unit with the rotation speed detecting device of the present invention is constructed and operates as described above, the output of the sensor can be increased without increasing the size of the rolling bearing unit with the rotation speed detecting device. Thus, the accuracy of detecting the rotational speed of the wheels can be sufficiently improved.

[Brief description of the drawings]

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

FIG. 2 is an enlarged view of a portion A in FIG.

FIG. 3 is a cross-sectional view of a main part of the structure of FIG. 1, showing a state in which an electromotive force is generated in the opposite direction as the tone wheel rotates.

FIG. 4 is a view showing a second example of the embodiment of the present invention and corresponding to an enlarged view of the right part of FIG. 1;

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

FIG. 6 is a perspective view showing the internal structure of a sensor used in the structure shown in FIG. 6;

FIG. 7 is a plan view of the internal structure of the sensor, showing a state in which an electromotive force is generated in the reverse direction with the rotation of the tone wheel in the structure of FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1a Rotating wheel 2, 2a Fixed wheel 3 Rolling element 4 Tone wheel 5 Sensor 6, 6a Inner ring 7 Inner ring track 8 Outer ring track 9 Through hole 10 Cover 11 Stator 12 Coil 13 Permanent magnet 14 End face 15 End face 16 Column part 17 Conducting wire 18 Cage 19 Seal assembly 20 Space 21 Inner seal ring 22 Outer seal tube 23, 23a Seal ring 24 Core bar 25 Seal material 26 Flange 27 Flange 28 Male screw part 29 Nut 30 Space 31 Tone wheel 32 First cylindrical part 33 Flange part 34 Second cylindrical portion 35 Through hole 36 Column portion 37 Cover 38 Sensor 39 Synthetic resin 40, 40a First stator element 41, 41a Second stator element 42, 42a Stator 43 Bobbin 44 Coil 45 Permanent magnet 46 First comb Toothed edge 47 Projection 48, 48a Notch 49 Second comb-like edge 50 Micro gap 51 Connector

Claims (3)

[Claims] 1. A sensor which is supported by a fixed wheel which does not rotate during use, and a tone wheel which is provided concentrically with the fixed wheel and is supported by a rotating wheel which rotates during use and rotates together with the rotating wheel. At least a portion of the tone wheel opposed to the sensor is provided with a rotation speed detecting device in which first portions and second portions having different magnetic properties are alternately arranged at equal pitches in the circumferential direction. In the rolling bearing unit, a magnetic material is supported on a part of the fixed wheel, and the magnetic material is opposed to at least a part of the tone wheel at a position opposite to the sensor and a part of the sensor. The tone wheel has a first cylindrical portion supported at an end of the rotating wheel, a flange bent in a diametric direction from an end of the first cylindrical portion, A second cylindrical portion extending in the axial direction from the end portion, the sensor is an annular stator arranged concentrically with the tone wheel, and the same poles are abutted or approached to both ends of the stator, One other pole is wound on the flange portion, and the other pole is wound on a pair of permanent magnets which are close to a part of the tone wheel or a part of the magnetic material, and a middle part of the stator. A plurality of protrusions and notches are provided at both end edges of the stator alternately in the circumferential direction and at the same pitch as the first portion and the second portion provided on the tone wheel. By providing, each comb-shaped edge is formed, and the other comb-shaped edge is formed at the moment when each protruding portion forming one comb-shaped edge faces the first portion. Replace each protrusion with the second part It is opposed to,
A rolling bearing unit with a rotation speed detecting device, wherein the sensor, the tone wheel, and the magnetic material form a closed loop magnetic circuit. 2. The rolling bearing with a rotation speed detecting device according to claim 1, wherein all the semicircular portions that match with each other among the comb-shaped end portions provided at both end portions of the stator are cut out. Unit bearing unit. 3. The rolling bearing unit according to claim 1, wherein the magnetic material is omitted.