JPH0953634A - Rolling bearing unit provided with rotating speed detection function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure having high detection accuracy even at slow speed and high degree of freedom in design. SOLUTION: A beam emitted from a light emitting element 35 constituting a sensor 23 is reflected by a half mirror 37 and reaches the inside face of a tone wheel 21. A lot of reflection sections are intermittently provided in the inside face of this tone in its peripheral directions. The beam reflected by a reflection section reaches a light receiving element 36 after transmitting the half mirror 37. This constitution enhances the degree of freedom in arranging members, facilitating the design for incorporating rolling bearing units of a variety of structure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION A rolling bearing unit having a rotation speed detecting function according to the present invention is used to rotatably support an automobile wheel on a suspension device and to detect the rotation speed of the wheel.

[0002]

2. Description of the Related Art A vehicle wheel is rotatably supported by a suspension system and the rotational speed of the wheel is detected in order to control an antilock brake system (ABS) or a traction control system (TCS). As a rolling bearing unit having a rotation speed detecting function for the purpose, various structures have been conventionally known. Each of the rotation speed detection devices incorporated in the rolling bearing unit having such a rotation speed detection function is a tone wheel that rotates with the wheel and a sensor that outputs an output signal that changes at a frequency proportional to the rotation speed of the tone wheel. With. Various types of tone wheels and sensors have been conventionally known.

FIG. 6 shows the structure disclosed in Japanese Patent Laid-Open No. 3-6458. On the outer peripheral surface of the outer end portion of the hub 1 that constitutes the rotating wheel (outer means the side that is outside the width direction of the vehicle when assembled to the vehicle, left in each drawing except FIGS. 4, 5, and 8), A flange portion 2 for fixing a wheel is formed, and an inner ring raceway 3a which is a rotation side raceway surface and a step portion 4 are formed on an intermediate portion outer peripheral surface which is a second peripheral surface. or,
On the outer peripheral surface of the hub 1, an inner ring raceway 3b which is a rotation side raceway surface is formed on the outer peripheral surface which is also a second peripheral surface.
The inner ring member 5, which also constitutes the rotary wheel, is externally fitted and supported with its outer end face abutting against the step portion 4.

A spline groove 6 is formed on the inner peripheral surface of the hub 1. A drive shaft that is rotationally driven via a constant velocity joint (not shown) is engaged with the spline groove 6 so that the hub 1 can be rotationally driven. Incidentally, the inner end surface of the inner ring member 5 in the assembled state to the vehicle (inside means the side which is the center in the width direction of the vehicle in the assembled state to the vehicle,
The right side of each drawing except FIGS. 4, 5, and 8 is in contact with the shoulder portion of the constant velocity joint to prevent loosening from the outer peripheral surface of the hub 1.

On the other hand, a mounting portion 8 for fixing the outer ring-equivalent member 7 to the suspension device is provided on the outer peripheral surface of the intermediate portion of the outer ring-equivalent member 7 which is a fixed ring and is arranged around the hub 1. . Further, outer ring raceways 9a, 9b, which are fixed-side raceway surfaces, are formed on the inner circumferential surface of the outer ring equivalent member 7, which is the first circumferential surface, and which face the inner ring raceways 3a, 3b, respectively. There is. A plurality of rolling elements 10 are provided between the inner ring raceways 3a and 3b and the outer ring raceways 9a and 9b, respectively.
10 is provided so that the hub 1 can freely rotate inside the member 7 corresponding to the outer ring.

Further, seal rings 11, 11 are mounted between the inner peripheral surfaces of both ends of the outer ring corresponding member 7 and the outer peripheral surfaces of the hub 1 and the inner ring member 5, so that the inner peripheral surface of the outer ring corresponding member 7 is mounted. Between the outer peripheral surface of the hub 1 and the outer peripheral surface of the hub 1 to close the openings at both ends of the space in which the plurality of rolling elements 10 and 10 are provided.

On the outer peripheral surface of the intermediate portion of the hub 1, between the rolling elements 10 provided in two rows, a tone wheel 12 made of a magnetic material in an annular shape is externally fitted and fixed. ing. Gear-shaped irregularities are formed on the outer peripheral surface of the tone wheel 12 so that the magnetic characteristics in the circumferential direction are alternately formed.
Moreover, it is changed at an equal pitch. The end surface of the sensor 13 provided through the outer ring equivalent member 7 is opposed to the outer peripheral surface of the tone wheel 12. The sensor 13 includes a permanent magnet and a magnetic detection element such as a Hall element or a magnetic resistance element.

When the rolling bearing unit having the rotational speed detecting function constructed as described above is used, when the tone wheel 12 rotates together with the hub 1, the tone wheel 12 rotates.
The density of the magnetic flux flowing in the sensor 13 facing the sensor changes. As a result, the signal obtained at the magnetic detection element portion of the sensor 13 changes at a frequency proportional to the rotation speed of the hub 1. Therefore, if the output signal of the sensor 13 is input to a controller (not shown), the rotation speed of the wheel rotating together with the hub 1 can be detected and the ABS or TCS can be controlled.

On the other hand, Japanese Utility Model Laid-Open No. 2-101273 discloses a rolling bearing unit having a rotational speed detecting function having a structure as shown in FIGS. In this rolling bearing unit having a rotational speed detecting function, a tone wheel 15 formed by bending a metal plate into an L-shaped cross section and forming an entire ring on the outer peripheral surface of an inner ring 14 that is a rotary wheel is externally fixed. ing. On the other hand, a sensor 17 is fixed to the inner peripheral surface of the outer ring 16 which is a fixed ring. This sensor 17
The whole is formed in a bifurcated shape, and a light emitting element such as a semiconductor laser and a light emitting diode and a light receiving element such as a phototransistor are provided in a state of being opposed to each other via a portion near the outer periphery of the tone wheel 15. A plurality of through holes 18, which are light transmitting portions, are provided in a portion of the tone wheel 15 near the outer periphery between the light emitting element and the light receiving element.
18 are intermittently provided at equal intervals.

In the case of the rolling bearing unit having the rotational speed detecting function configured as described above, light is intermittently sent to the light receiving element of the sensor 17 as the inner ring 14 rotates.
The time interval at which light is sent to the light receiving element of the sensor 17 changes depending on the rotation speed of the inner ring 14. Therefore, the sensor 17
The rotation speed of the inner ring 14 and the member fixed to the inner ring 14 can be known from the signal from the.

[0011]

In the case of the rolling bearing unit having the conventionally known rotation speed detecting function, which is constructed and operates as described above, it suffices if the traveling speed of the vehicle is somewhat high. , It is difficult to secure sufficient detection accuracy at extremely low speeds. The reason for this is as follows.

In order to reliably detect the rotation speed, it is necessary to increase the output of the sensor 13 to some extent.
In order to increase the output of the sensor 13 with the structure of the first example shown in FIG. 1, the density change of the magnetic flux flowing in the sensor 13 must be increased. Since the magnetic flux flowing in the sensor 13 constitutes the closed circuit including the tone wheel 12, the facing area between the tone wheel 12 and the end face of the sensor 13 is widened to a certain extent, and the amount of magnetic flux flowing in the tone wheel 12 is increased. Need to be a lot. In order to widen the facing area, it is necessary to increase the circumferential length of the concave portions and the convex portions alternately formed on the outer peripheral surface of the tone wheel 12 to some extent. Therefore, the pitch of the unevenness formed on the outer peripheral surface of the tone wheel 12 cannot be made very fine. For example, in order to bring the output of the sensor 13 to a sufficiently practical level with the structure as shown in FIG. 6, it is necessary to suppress the number of the irregularities to about 50 at the maximum.

Further, as the tone wheel, as shown in FIG. 6, in addition to a gear wheel-shaped unevenness formed on the outer peripheral surface, a tone-shaped magnetic metal plate having a through hole or a notch is formed. Known from the past. In order to secure the amount of magnetic flux flowing in such a tone wheel, it is necessary to increase the plate thickness of the magnetic metal plate to some extent. In order to form the above-mentioned through hole or notch in a magnetic metal plate having a large plate thickness, punching or cutting must be performed, but with such a processing method, the interval between adjacent through holes or notches is required. Can not be extremely short. Therefore, in the case of a tone wheel having such through holes or notches, it is necessary to suppress the number of these through holes or notches to 50 or less from the viewpoint of processing.

On the other hand, even when the automobile runs at an extremely low speed, in order to accurately detect the traveling speed (improve the detection accuracy), the output of the sensor changes while the hub makes one revolution. It is necessary to increase the number of times. For example, even if an automobile is moving at a speed much slower than the walking speed, in order to accurately measure the traveling speed, the output of the sensor may change 300 times or more during one rotation of the hub. A different rotation speed detection device is required.

On the other hand, in the structure of the second conventional example shown in FIGS. 7 to 8, the sensor 17 in which the light emitting element and the light receiving element are integrally incorporated to form a bifurcated structure is provided in the shaft of the outer peripheral edge portion of the tone wheel 15. These sensors 17 are arranged on both sides in the direction.
Also, the work of mounting the tone wheel 15 becomes troublesome. That is, it is necessary to interpose an appropriate gap between the sensor 17 and the tone wheel 15 so as not to rub against each other as the inner ring 14 rotates. However, in the structure of the second example, the sensor 17 and the tone wheel 15 have to be simultaneously mounted on the outer ring 16 and the inner ring 14, respectively, and the work of mounting them while ensuring an appropriate gap is troublesome. Is. Furthermore, since the positional relationship between the light emitting element and the light receiving element is fixed, the degree of freedom in design is low, and it may be considered that the optimum design cannot be performed depending on the structure of the rolling bearing unit.

Further, in the structure of the second example, it is difficult to increase the number of through holes 18, 18 formed in the tone wheel 15 from the viewpoint of ensuring the strength of the tone wheel 15, and measurement at low speed running is made. It is difficult to improve accuracy. That is,
In the case of the structure of the second example, the entire tone wheel 15 is formed of one metal plate, and this metal plate is externally fitted and fixed to the inner ring 14. Therefore, in order to secure the fitting and fixing strength, it is necessary to use the metal plate having a thickness of about 0.5 mm or more. However, in the case of a metal plate having a thickness of about 0.5 mm or more, it is impossible to extremely shorten the interval between the adjacent through holes or notches as described above, because the distortion during processing needs to be suppressed. . If the work of forming the through holes 18, 18 is performed by etching instead of pressing or cutting, the number of the through holes 18, 18 can be increased, but the tone wheel 15 having a large plate thickness can be used. Since the work of forming the through holes 18, 18 by the etching process requires time and causes a high cost,
Not preferred. The rolling bearing unit having the rotational speed detecting function of the present invention was invented in view of such circumstances.

[0017]

A rolling bearing unit which constitutes a rolling bearing unit having a rotational speed detecting function of the present invention comprises a fixed ring having a fixed side raceway surface on a first peripheral surface, and the first ring. A rotary wheel having a rotation-side raceway surface on a second circumferential surface facing the circumferential surface, and a plurality of rolling elements rotatably provided between the fixed-side raceway surface and the rotation-side raceway surface.

Further, the rotation speed detecting device changes the reflection characteristics alternately and at equal intervals in the circumferential direction, and includes a tone wheel fixed to the rotating wheel, and a sensor supported on the fixed portion. Equipped with. The sensor includes a light emitting element, a light receiving element, and a half mirror. The half mirror sends the light emitted from the light emitting element toward the tone wheel, and sends the light reflected by the tone wheel to the light receiving element.

The sensor can be supported not only on the fixed wheel but also on the controller side provided on the vehicle body side.
In this way, when the sensor is installed away from the rolling bearing unit, an optical fiber cable is provided between the half mirror and the tone wheel, and light is emitted between the half mirror and the tone wheel. Configure to reciprocate in the cable. In this case, the front end surface of the optical fiber cable is brought into close proximity to the surface of the tone wheel, and the base end surface is brought close to the half mirror.

[0020]

In the rolling bearing unit having the rotational speed detecting function of the present invention configured as described above, the light emitted from the light emitting element constituting the sensor is converted in its traveling direction by the half mirror and then the tone wheel is rotated. Reach Then, the light is reflected by the surface of the tone wheel, reaches the light receiving element after passing through the half mirror. Since the reflection characteristics of the surface of the tone wheel change alternately and at regular intervals in the circumferential direction, when the tone wheel rotates together with the rotating wheel while the vehicle is running, the tone wheel surface is reflected. The amount of light reaching the light receiving element changes. Therefore, the detection signal of the light receiving element changes at a frequency proportional to the rotation speed of the rotating wheel. Since the detection signal of the light receiving element changes abruptly according to the change in the reflection characteristic, the detection signal can be easily determined and the rotation speed can be surely detected.

The tone wheel and the sensor can be fixed to a fixed wheel or a rotating wheel independently of each other.
Therefore, it becomes easy to attach and fix the tone wheel and the sensor to the fixed wheel or the rotating wheel while ensuring a proper gap between them. Also, since these tone wheels and sensors are provided independently of each other, a certain degree of freedom in arrangement of these tone wheels and sensors is secured,
The degree of freedom in design can be increased, and the rotation speed detection device can be incorporated in the rolling bearing unit having various structures. Further, it is possible to improve the accuracy of rotation speed detection by making the pitch at which the reflection characteristic changes on the surface portion of the tone wheel fine.

Further, if an optical fiber cable is provided, the degree of freedom in arranging the light emitting element, the light receiving element, and the half mirror which compose the sensor can be further increased, and light from the outside does not enter the light receiving element as noise. .

[0023]

1 and 2 show a first embodiment of the present invention. A flange portion 2 for fixing a wheel is formed on an outer peripheral surface of an outer end portion of a hub 1a constituting a rotating wheel, and an inner peripheral surface of a rotating side raceway surface is formed on an outer peripheral surface of an intermediate portion which is a second peripheral surface. Orbit 3
a and the step 4 are formed. Further, on the outer peripheral surface of the hub 1a, an inner ring member 5 which is also a rotating ring, is formed on the outer peripheral surface which is also a second peripheral surface. Is externally fitted and supported in a state of abutting against the step portion 4. The inner ring raceway 3a
Instead of being formed directly on the outer peripheral surface of the hub 1a,
In some cases, the inner ring member and the inner ring member 5 are formed separately from the inner ring member (not shown), and the inner ring member and the inner ring member 5 are externally fitted and fixed to the hub 1a.

Further, a male screw portion 19 is formed on a portion near the inner end of the hub 1a. Then, the inner ring member 5 is fixed to a predetermined portion on the outer peripheral surface of the hub 1a by a nut 20 screwed into the male screw portion 19 and further tightened. A mounting portion 8 for fixing the outer ring-equivalent member 7 to the suspension device is provided on the outer peripheral surface of the intermediate portion of the outer ring-equivalent member 7 which is a fixed ring and is arranged around the hub 1a. Also, the first peripheral surface,
Outer ring raceways 9a and 9b, which are fixed-side raceway surfaces, are formed on the inner peripheral surface of the member 7 corresponding to the outer ring, which face the inner ring raceways 3a and 3b, respectively. A plurality of rolling elements 10 and 10 are provided between the inner ring raceways 3a and 3b and the outer ring raceways 9a and 9b, respectively, so that the hub 1a can freely rotate inside the outer ring member 7. .
Although balls are used as the rolling elements 10 in the illustrated example, tapered rollers may be used as the rolling elements in the case of a rolling bearing unit for an automobile, which is heavy in weight.

Seal rings 11a and 11b are mounted between the inner peripheral surfaces of both ends of the outer ring equivalent member 7 and the inner peripheral surfaces of the hub 1a and the inner ring member 5. The seal rings 11a and 11b are provided between the inner peripheral surface of the outer ring-equivalent member 7 and the outer peripheral surface of the hub 1a to open the openings at both ends of the space where the plurality of rolling elements 10 and 10 are provided. It is blocking. In particular, the seal ring 1 provided between the inner peripheral surface of the inner end portion of the outer ring equivalent member 7, the outer peripheral surface of the inner end portion of the inner ring member 5, and the outer peripheral surface of the retaining ring 22 described below.
1b prevents the grease existing in the installation portions of the rolling elements 10 and 10 from entering the tone wheel 21, which will also be described below, and the sensor 23 portion, which will be described later.

If a light-transmissive grease is used as the grease, the seal ring 11b can be omitted from the aspect of protecting the rotation speed detecting device. However, the amount of grease used is reduced (the amount of grease present in the rolling elements 10, 10 does not have to be increased by preventing the grease from entering the inside of the cover 24 described later). To secure the above), the above seal ring 11b
Is preferably provided.

A retaining ring 22 is externally fitted and fixed to the inner end portion of the inner ring member 5, and an annular tone wheel 21 made of synthetic resin or the like is supported and fixed to the inner side surface of the retaining ring 22. . The holding ring 22 is made of a metal plate having sufficient rigidity and is formed into an annular shape with an L-shaped cross section. The cylindrical portion 25 of the retaining ring 22 is externally fitted to the inner end portion of the inner ring member 5, and the tone wheel 21 is fixed to the inner side surface of the circular ring portion 26 by adhesion or the like. The reflection characteristics of the inner surface of the tone wheel 21 are changed alternately and at equal intervals in the circumferential direction.

Although various methods of alternately changing the reflection characteristics can be considered, the following methods (1) to (4) can be used. The tone wheel 21 is made of a material with low reflectance,
On the inner surface of the tone wheel 21, a large number of portions having a high reflectance such as metal plating are formed intermittently in the circumferential direction. The tone wheel 21 is made of a material having a high reflectance such as a stainless steel plate, and on the inner surface of the tone wheel 21, a portion having a low reflectance, such as a black matte coating, is intermittently arranged in a number of locations in the circumferential direction. Form. On the inner surface of the tone wheel 21 of any material, a large number of portions having the above-described reflectance and a portion having the small amount of the reflectance as described above are alternately formed in the circumferential direction at a large number of portions. . The tone wheel 21 is made of a material having a large reflectance, such as a stainless steel plate and a highly functional resin having a bright color such as white. The tone wheel 21 has a mountain-shaped protrusion on the inner surface thereof, which is long in the diameter direction, as shown in FIG. 27, 27 are intermittently formed in a large number of places in the circumferential direction. As shown in FIG. 5A, the flat portion 2 existing between the adjacent protrusions 27, 27.
The light that hits 8 is reflected in the direction that it is sent, but as shown in FIG. 7B, the light that hits the protrusion 27 is reflected to the side and returned in the direction that it was sent. Absent. The thickness of the tone wheel 21 does not necessarily have to be large as shown in the figure. Further, the retaining ring 22 can be made to function as the tone wheel 21 by alternately changing the reflection characteristics of the inner side surface of the circular ring portion 26 of the retaining ring 22 in the circumferential direction.

On the other hand, at the inner end opening of the member 7 corresponding to the outer ring, a cover 24 is formed by drawing a metal plate.
Is externally fixed. In the illustrated embodiment, the cover 24 has a large diameter portion 29 on the opening side and a small diameter portion 30 on the bottom side. The first half of the nut 20 is inserted into the inner diameter side of the small diameter portion 30. Also, these large diameter parts 2
A part of the stepped portion 31 that connects 9 and the small diameter portion 30 is slightly inwardly projected to form, for example, a fan-shaped mounting portion 32 (as viewed from the right side of FIG. 1). And
The synthetic resin 3 with the sensor 23 embedded in the mounting portion 32
3 are provided. A through hole is provided in a part of the mounting portion 32, and the synthetic resin 33 and the synthetic resin forming the connector 34 are fusion-bonded through the through hole.

The sensor 23 also includes a light emitting element 35 such as a semiconductor laser or a light emitting diode, a light receiving element 36 such as a phototransistor, a half mirror 37, and a slit plate 38. As the light emitting diode, for example, an infrared light emitting diode can be used. Each of these members 35
The sensor 23 composed of ˜38 is installed in the cavity 39 formed in the synthetic resin 33. This cavity 39
Includes a main hole portion 40 formed in a direction perpendicular to the inner surface of the tone wheel 21, and a branch hole portion 41 branched from the middle of the main hole portion 40 to the side at a right angle. The light-receiving element 36 is located at the innermost end of the main hole 40, and the light-emitting element 35 is located at the middle of the branch hole 41 so that their optical axes coincide with the axial centers of the holes 40, 41. It is fixed in the closed state. Further, the half mirror 37 is fixed to a portion of the intermediate portion of the main hole portion 40 facing the opening of the branch hole portion 41 in a state of being inclined by 45 degrees with respect to the axes of the both hole portions 40, 41. are doing. Further, the slit plate 38
Is fixed to the opening of the main hole 40 and faces the inner surface of the tone wheel 21. A conducting wire for energizing the light emitting element 35 and a conducting wire for taking out a signal of the light receiving element 36 are inserted through the through holes formed in the mounting portion 32.

Since the sensor 23 is constructed as described above, the light emitted from the light emitting element 35 is reflected by the half mirror 37.
Is reflected by and sent to the inner surface of the tone wheel 21. The light reflected on the inner surface of the tone wheel 21 passes through the half mirror 37 and is sent to the light receiving element 36. In addition, a plurality of slits (for example, 2 to 3) are formed in the slit plate 38 at the same pitch as the reflecting portions formed on the inner surface of the tone wheel 21. In the slit plate 38, the light emitted from the light emitting element 35 toward the tone wheel 21 via the half mirror 37 is diffused, and the light is always emitted to the light receiving element 36 regardless of the rotation of the tone wheel 21. It is provided in order to prevent it from remaining. Therefore, the light emitting element 3
If a semiconductor laser that hardly diffuses light is used as 5, the slit plate 38 can be omitted. Further, the light emitting element 35 and the light receiving element 36 can be arranged in the opposite manner to the illustrated embodiment.

In the case of the rolling bearing unit having the rotational speed detecting function of the present invention configured as described above, the light emitted from the light emitting element 35 constituting the sensor 23 travels in the traveling direction 90 by the half mirror 37. After being converted, the inner surface of the tone wheel 21 is reached. The light reflected on the inner surface reaches the light receiving element 36 after passing through the half mirror 37. When the tone wheel 21 rotates together with the hub 1a while the vehicle is running, the amount of light reflected by the inner surface of the tone wheel 21 and reaching the light receiving element 36 changes. Therefore, the detection signal of the light receiving element 36 changes at a frequency proportional to the rotation speed of the hub 1a. The detection signal of the light receiving element 36 changes abruptly depending on whether the light emitted from the light emitting element 35 reaches a portion having a large reflectance on the inner surface of the tone wheel 21 or a portion having a small reflectance. To do. Therefore, the detection signal can be easily determined, and the rotation speed can be surely detected.

The sensor 23 is integrally held in the synthetic resin 33 supported by the cover 24. After the tone wheel 21 is externally fitted and fixed to the inner ring member 5, the cover 24 is fixed to the outer ring member. It can be easily mounted by fitting it on the inner end of 7. Therefore, the work of attaching and fixing the sensor 23 to the member 7 corresponding to the outer ring while ensuring an appropriate gap with the tone wheel 21 becomes easy. Further, it is possible to secure a certain degree of freedom in arranging the sensor 23 and the tone wheel 21 to increase the degree of freedom in design, and to incorporate the rotation speed detecting device into the rolling bearing unit having various structures. For example, in the case of the present embodiment, the sensor 23 and the tone wheel 21 are arranged so as to face each other in the axial direction, so that the dimension of the rotational speed detecting device in the diameter direction is reduced. On the other hand, for example, at least a part of the tone wheel is made cylindrical, and the reflection characteristics of the peripheral surface of this cylindrical portion are alternately changed in the circumferential direction,
It is also possible to make the sensor face the peripheral surface of this cylindrical portion.

Next, FIGS. 3 to 4 show a second embodiment of the present invention. In the case of the present embodiment, the sensor 23 including the light emitting element 35, the light receiving element 36, and the half mirror 37 is built in a controller provided on the vehicle body side apart from the rolling bearing unit. Then, between the half mirror 37 constituting the sensor 23 and the inner surface of the tone wheel 21,
An optical fiber cable 42 is provided. Slit plate 38
Is provided at a portion of the tip end surface of the optical fiber cable 42 that faces the inner side surface of the tone wheel 21.
Also, between the light emitting element 35 and the half mirror 37,
A slit plate 43 is provided to prevent light diffusion.
Further, in the mounting portion 32 portion of the cover 24, a cable element 42a (FIG. 4) disposed on the vehicle body side and a cable element 42b (FIG. 3) disposed inside the cover 24 of the optical fiber cable 42 are provided. An optical connector 45 for connection is provided.

In the case of this embodiment configured as described above, the light emitted from the light emitting element 35 and passing through the slit plate 43 has its traveling direction converted by 90 degrees by the half mirror 37, and then the optical fiber cable 42. Into the optical fiber cable 42,
The inner surface of the tone wheel 21 is reached. Then, the light reflected on the inner surface is the optical fiber cable 42.
Of the light receiving element 36 after entering the optical fiber cable 42 from the front end surface of the
Reach As described above, in the case of the present embodiment, since the sensor 23, which requires a relatively large installation space, is installed on the vehicle body side away from the rolling bearing unit, the degree of freedom in the arrangement of the sensor 23 can be further increased, and especially the installation is possible. It can be applied to rolling bearing units with limited space. Moreover, since the light from the outside does not enter the light receiving element as noise, more stable rotation speed detection becomes possible.

In each of the illustrated embodiments, the non-driving wheels (F
It shows a structure in which the present invention is applied to a rolling bearing unit for supporting front wheels of an R vehicle and rear wheels of an FF vehicle. However,
The present invention is not limited to such non-driving wheels, but also to a rolling bearing unit for supporting the driving wheels (rear wheels of FR vehicles, front wheels of FF vehicles, all wheels of 4WD vehicles) as shown in FIG. Applicable. Further, it can be applied to a rolling bearing unit in which the inner ring side is fixed and the outer ring side rotates.

[0037]

Since the rolling bearing unit having the rotational speed detecting function of the present invention is constructed and operates as described above, the traveling speed can be surely detected even at an extremely low speed, and the AB
It becomes possible to control S and TCS more accurately. Further, for example, since it is possible to accurately measure the speed difference between the right wheel and the left wheel, it becomes possible to accurately change the traveling direction of the vehicle and the measurement distance, and to accurately measure the self-supporting traveling type. It can contribute to the realization of a navigation system. Moreover, since the degree of freedom in arranging the constituent members is great, it becomes possible to incorporate the rotation speed detecting device into a rolling bearing unit having various structures by utilizing an empty space of the rolling bearing unit.

[Brief description of drawings]

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

FIG. 2 is an enlarged sectional view showing a tone wheel and a sensor taken out.

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

FIG. 4 is a plan view showing the components of the sensor taken out.

FIG. 5 is a partially enlarged cross-sectional view showing a structure in which the reflection characteristics are changed by changing the shape of the tone wheel surface.

FIG. 6 is a sectional view showing a first example of a conventional structure.

FIG. 7 is a sectional view showing the second example.

FIG. 8 is a diagram of the tone wheel and the sensor as viewed from the right side of FIG. 7.

[Explanation of symbols]

 1, 1a Hub 2 Flange part 3a, 3b Inner ring raceway 4 Step part 5 Inner ring member 6 Spline groove 7 Outer ring equivalent member 8 Mounting part 9a, 9b Outer ring raceway 10 Rolling element 11, 11a, 11b Seal ring 12 Tone wheel 13 Sensor 14 Inner ring 15 tone wheel 16 outer ring 17 sensor 18 through hole 19 male screw portion 20 nut 21 tone wheel 22 retaining ring 23 sensor 24 cover 25 cylindrical portion 26 circular ring portion 27 protrusion 28 flat portion 29 large diameter portion 30 small diameter portion 31 step portion 32 mounting portion 33 Synthetic resin 34 Connector 35 Light emitting element 36 Light receiving element 37 Half mirror 38 Slit plate 39 Cavity 40 Main hole 41 Branch hole 42 Optical fiber cable 42a, 42b Cable element 43 Slit plate 45 Optical connector

Claims (1)

[Claims] 1. A fixed wheel having a fixed side raceway surface on a first circumferential surface, a rotary wheel having a rotary side raceway surface on a second circumferential surface facing the first circumferential surface, and the fixed side raceway. A plurality of rolling elements provided rotatably between the surface and the raceway surface on the rotation side, and the reflection characteristics are alternately changed at equal intervals over the circumferential direction,
A tone wheel fixed to the rotating wheel and a sensor supported by the fixed portion are provided. The sensor includes a light emitting element, a light receiving element, and a half mirror, and the half mirror is illuminated by the light emitting element. Rolling bearing unit having a rotation speed detecting function for sending light to the tone wheel and sending light reflected by the tone wheel to the light receiving element.