JP2003146196A - Rotational speed detection device for wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotational speed detection device for a wheel structured to transmit by wireless a signal of a rotation detection sensor 39 provided on the rolling bearing unit side for wheel supporting to a controller 36 provided on the car body side and capable of freely judging a failure of this rotation detection sensor 39. SOLUTION: A judgement circuit 57 to judge existence of the failure of this rotation detection sensor 39 is provided on a sensor unit 44 including the rotation detection sensor 39 or on the controller 36. An above subject is solved by judging existence of abnormality of the rotation detection sensor 39 by this judgement circuit 57 before or after starting travelling.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The rotation speed detecting device according to the present invention is used to detect the rotation speed of a vehicle wheel.

[0002]

2. Description of the Related Art An anti-lock brake system (AB for ensuring vehicle stability during braking and acceleration)
In order to control S) and the traction control system (TCS), it is necessary to detect the rotation speed of the wheels. Therefore, the rolling bearing unit with a rotation speed detecting device, which has a rotation speed detecting device incorporated in a rolling bearing unit for rotatably supporting the wheel with respect to the suspension device, rotatably supports the wheel with respect to the suspension device. With
In recent years, the detection of the rotation speed of the wheel has been widely performed.

A rolling bearing unit with a rotation speed detecting device used for such a purpose is disclosed in Japanese Patent Laid-Open No. 11-2359.
The publication No. 6 describes a structure as shown in FIGS. First, the rolling bearing unit 1 with a rotation speed detecting device according to the first example of the conventional structure shown in FIG. 10 has a rolling bearing unit 2 and a rotation speed detecting device 3 incorporated therein. Of these, the rolling bearing unit 2 includes an outer ring 4 which is a stationary wheel.
A hub 5 and an inner ring 6 which are rotating wheels are rotatably supported on the inner diameter side of the. The outer end of the hub 5 (the left end in each drawing showing the rolling bearing unit, which is the end on the outer side in the width direction when assembled to a vehicle, is the same throughout this specification).
First flange 7 for attaching wheels to the outer peripheral surface of
And a first inner ring raceway 8 is provided on the outer peripheral surface of the intermediate portion. Further, the inner ring 6 has a second inner ring raceway 9 on the outer peripheral surface thereof, and refers to the inner end of the hub 5 (the end which is the inner side in the width direction when assembled to a vehicle, and each rolling bearing unit is described. (The right end of the figure. The same throughout the specification.) It is externally fitted to the stepped portion 10 which is formed in a side portion and has an outer diameter smaller than that of the portion where the first inner ring raceway 8 is provided.
A first outer ring raceway 11 facing the first inner ring raceway 8 and a second outer ring raceway 12 facing the second inner ring raceway 9 are provided on the inner circumferential surface of the outer ring 4, and the outer circumferential surface is provided with the second outer ring raceway 12 facing the second inner ring raceway 9. Second flanges 13 for supporting the outer ring 4 on the suspension device are respectively formed. A plurality of rolling elements 14 and 14 are provided between the first and second inner ring raceways 8 and 9 and the first and second outer ring raceways 11 and 12, respectively. The hub 5 and the inner ring 6 are rotatably supported on the side. In the state where the inner ring 6 is fitted onto the step portion 10, a nut 15 is screwed into a male screw portion formed on the inner end portion of the hub 5 to hold down the inner ring 6 and the inner ring 6 and the inner ring 6 together. The separation from the hub 5 is prevented.

The inner end (right end in FIG. 10) of the outer ring 4 is closed by a cover 16. This cover 16
Is a bottomed cylindrical main body 17 formed by injection molding a synthetic resin.
And a fitting cylinder 18 made of a metal plate, which is connected to the opening of the main body 17. The fitting cylinder 18 is joined to the opening of the main body 17 by molding the base end portion of the main body 17 during injection molding. The cover 16 configured in this way is provided with the first half of the fitting cylinder 18 (the left half of FIG. 10).
Is externally fitted and fixed to the inner end portion of the outer ring 4 by interference fitting, thereby closing the inner end opening portion of the outer ring 4.

On the other hand, in order to configure the rotation speed detecting device, an encoder is provided on a portion of the outer peripheral surface of the inner end portion of the inner ring 6 fitted and fixed to the inner end portion of the hub 5 from the second inner ring raceway 9. 19 is externally fitted and fixed. This encoder 19
Is composed of a support ring 20 and a permanent magnet 21. The support ring 20 is formed by bending a magnetic metal plate such as SPCC into an annular shape with an L-shaped cross section, and is fixed to the inner end of the inner ring 6 by interference fitting. Further, the permanent magnet 21 is formed by, for example, attaching rubber mixed with ferrite powder to the inner side surface of the ring portion forming the support ring 20 by baking or the like. The permanent magnets 21 are magnetized, for example, in the axial direction (the left-right direction in FIG. 10) and are changed in the circumferential direction alternately and at equal intervals. Therefore, the S poles and the N poles are alternately arranged at equal intervals in the circumferential direction on the inner surface of the encoder 19, which is the detected portion.

Further, an insertion hole 22 is formed in a part of the main body 17 forming the cover 16 facing the inner surface of the permanent magnet 21 forming the encoder 19.
Is formed so as to extend in the axial direction of the cover 16. Then, the sensor 23 is inserted into the insertion hole 22.
Have been inserted. The sensor 23 is an IC incorporating a magnetic detection element such as a Hall element or a magnetic resistance element (MR element) that changes its characteristics depending on the flow direction of the magnetic flux, and a waveform shaping circuit for adjusting the output waveform of the magnetic detection element. When,
A magnetic pole piece or the like for guiding a magnetic flux emitted from the permanent magnet 21 (or flowing into the permanent magnet 21) to the magnetic detection element is embedded in a synthetic resin.

Such a sensor 23 is provided at a portion near the tip (the left end in FIG. 10) and has a cylindrical insertion portion 24 that can be inserted into the insertion hole 22 without rattling, and the base end of the insertion portion 24. And a flange portion 25 having an outward flange shape, which is formed on the portion (right end portion in FIG. 10). A locking groove is formed on the outer peripheral surface of the intermediate portion of the insertion portion 24, and the O-ring 2 is formed in the locking groove.
6 is locked.

On the other hand, the insertion hole 22 is formed at a part of the outer surface of the cover 16 (the side surface opposite to the space 27 in which the rolling elements 14, 14 are to be closed, which is the right side surface in FIG. 10) to be closed by the cover 16. A locking cylinder 28 is provided around the opening. In the sensor 23, the insertion portion 24 is inserted into the locking cylinder 28, the collar 25 is abutted against the tip end surface of the locking cylinder 28, and the locking spring 29 causes the locking cylinder 28 to move. 28, and is supported. Incidentally, regarding such a coupling and supporting structure by the locking spring 29, the above-mentioned Japanese Patent Laid-Open No. 11-2359 is used.
It is described in detail in Japanese Patent Publication No. 6 and is not related to the gist of the present invention, so detailed illustration and description thereof will be omitted.

When the rolling bearing unit 1 with a rotation speed detecting device as described above is used, the second flange 13 fixedly mounted on the outer peripheral surface of the outer ring 4 is coupled and fixed to the suspension device by a bolt (not shown). By fixing the wheel to the first flange 7 fixed to the outer peripheral surface of the hub 5 by the stud 30 provided on the first flange 7, the wheel is rotatably supported with respect to the suspension device. To do. When the wheel rotates in this state, the N pole and the S pole existing on the inner side surface of the permanent magnet 21 alternately pass near the end face of the detecting portion of the sensor 23. As a result, the direction of the magnetic flux flowing in the sensor 23 changes, and the output of the sensor 23 changes. The frequency at which the output of the sensor 23 changes in this manner is proportional to the rotational speed of the wheel. Therefore, if the output of the sensor 23 is sent to a controller (not shown), ABS and TCS can be controlled appropriately.

Further, the above-mentioned Japanese Patent Laid-Open No. 11-23 shown in FIG.
In the case of the second example of the conventional structure described in Japanese Patent No. 596, the cylindrical portion 31 is formed at the inner end portion of the hub 5a, and the end portion of the cylindrical portion 31 projects from the inner end surface of the inner ring 6. The caulking portion 34 is formed by expanding the caulking outward in the diametrical direction, and the caulking portion 34 causes the inner ring 6 to move to the hub 5a.
It is fixed by binding to. If such a structure is adopted,
Compared to the structure in which the inner ring 6 is coupled and fixed to the hub 5 with the nut 15 as in the first example of the conventional structure shown in FIG. 10 described above, the number of parts is reduced and the labor for assembling is reduced, resulting in cost reduction. Can be achieved. The second structure of the conventional structure shown in FIG.
In the case of the example, the structure of the portion in which the sensor 23a is coupled to and supported by the locking cylinder 28 provided in the main body 17 of the cover 16 by the locking spring 29a is different from the case of the first example described above. However,
Such a combined support structure using the locking spring 29a is also described in detail in the above-mentioned JP-A-11-23596.
Further, since it is not related to the gist of the present invention, detailed illustration and description thereof will be omitted. Moreover, in the case of the structure of the second example,
The encoder 19a is also different from the case of the first example described above. That is, the encoder 19a of the present example is formed by bending a magnetic metal plate such as a soft steel plate to have an L-shaped cross section and an annular shape as a whole. Then, a plurality of through holes 3 are formed in the circular ring portion 32.
3 is formed in a radial shape, and the magnetic characteristics of the circular ring portion 32 are
Around the circumferential direction, they are alternately changed at equal intervals.
In accordance with this, the internal structure of the sensor 23a is also different from that of the first example described above.

The conventional structure shown in FIGS. 10 to 11 is as follows.
In both cases, the detection signals from the sensors 23 and 23a are output to the harness 35.
Therefore, it is sent to the controller provided on the vehicle body side. On the other hand, Japanese Patent Application Laid-Open No. 2001-151090 describes a structure in which the detection signal of the rotation speed detection sensor is sent to a controller provided on the vehicle body side by wireless transmission. That is, a transmitter for wirelessly transmitting the detection signal is provided on the outer peripheral surface of the outer wheel, which is a stationary wheel, adjacent to the rotation speed detection sensor, and a harness for transmitting the detection signal is unnecessary. With such a configuration, a failure due to wire breakage of the harness due to flying stones or the like can be prevented, and the harness itself and its wiring work can be omitted to achieve weight reduction and cost reduction.

[0012]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the case of the conventional structure disclosed in Japanese Patent Publication No. 151090, it is necessary to prevent malfunction of ABS or TCS by detecting whether or not there is an abnormality in the rotation speed detection sensor or the transmission unit provided in the wheel supporting rolling bearing unit. I haven't taken any particular consideration. On the other hand, when the structure for wirelessly transmitting the detection signal is adopted, factors that generate an abnormal detection signal are increased as compared with the case where the harness is used, such as securing power for transmission. Further, in the case of a new structure for wireless transmission, the conventional structure in which a harness is used for transmitting signals and electric power cannot be applied as it is. In view of such circumstances, the rotation speed detection device of the present invention has a structure for performing wireless transmission and is invented to prevent malfunction of ABS or TCS.

[0013]

The rotation speed detecting device of the present invention constitutes a wheel supporting rolling bearing unit, as in the previously known rotation speed detecting device.
A rotating wheel that rotates together with the wheel during traveling, an encoder that is concentrically supported by the rotating wheel, and that alternately changes the characteristics of the detected part in the circumferential direction, and a state in which the detected part faces the detected part. And a rotation detection sensor supported by a portion that does not rotate. Then, the detection signal of this rotation detection sensor is wirelessly transmitted to the controller provided on the vehicle body side. In particular, the rotation speed detection device of the present invention includes a self-diagnosis circuit for determining whether or not there is an abnormality in the rotation detection sensor.

[0014]

The operation of detecting the rotational speed of the wheel supported by the suspension by the rotational speed detecting device of the present invention constructed as described above is the same as that of the conventional structure shown in FIGS. . Further, by wirelessly transmitting the detection signal, it is possible to prevent a failure due to wire breakage of the harness due to flying stones, etc., and to omit the harness itself and its wiring work, thereby achieving weight reduction and cost reduction. This is similar to the case of the conventional structure described in 2001-151090. Especially, in the case of the rotation speed detecting device of the present invention, since the self-diagnosis circuit for judging the presence or absence of abnormality of the rotation detecting sensor is provided, malfunction of ABS or TCS can be prevented, and safe operation of the vehicle can be achieved. .

[0015]

1 to 3 show a first example of an embodiment of the present invention corresponding to claims 1 and 2. still,
A feature of the present invention is that the rotation speed of the hub 5 and the inner ring 6 that are rotating wheels is detected, and a signal representing the detected values is wirelessly transmitted to the controller 36 provided on the vehicle body side. 39 is a part for determining the presence or absence of abnormality. Rolling bearing unit 2 for supporting a wheel with respect to a suspension device
The structure and operation of the parts are the same as the structure generally known in the past including the first example of the conventional structure shown in FIG. 10 described above, and therefore the description thereof will be omitted or simplified. The description will focus on the characteristic part of.

The nut 15 is pressed against the hub 5 in a state of being externally fitted to the step portion 10 formed on the inner end portion of the hub 5, and the inner end portion of the inner ring 6 which constitutes a rotating wheel together with the hub 5 is The encoder 19b is externally fitted and fixed. In the case of this example, the encoder 19b is formed of a magnetic metal plate by bending so as to have an overall annular shape with a crank type cross section, and the inner diameter side cylindrical portion 37 and the outer diameter side cylindrical portion 38 are concentric with each other.
Have and. And in the outer diameter side cylindrical portion 38 of these,
Each of the slit-shaped through holes 33a, 33 is long in the axial direction.
Many a are formed at equal intervals in the circumferential direction. Then, the magnetic characteristics of the inner peripheral surface of the outer diameter side cylindrical portion 38, which is the surface to be detected of the encoder 19b, are changed alternately at equal intervals in the circumferential direction.

When the present invention is carried out, the encoder 19b may be one whose magnetic characteristics are alternately changed at equal intervals in the circumferential direction, for example, an S pole and an N pole on the inner peripheral surface. It may be a cylindrical permanent magnet in which and are alternately arranged at equal intervals, or an encoder made of a magnetic metal material having an inner gear-shaped unevenness formed on the inner peripheral surface. In this case, it is necessary to change the configuration of the rotation detection sensor 39 described later according to the difference in the properties of the encoder. That is, when the encoder having the permanent magnet is used, the rotation detection sensor 3
It is not necessary to incorporate a permanent magnet in 9, but if a simple encoder 19b made of magnetic material is used, the sensor side must be
It is necessary to incorporate a permanent magnet that is the source of magnetic flux.

On the other hand, the opening end of a cover 16a formed by plastically deforming a magnetic metal plate such as a steel plate to form a bottomed cylinder is fitted into the opening at the inner end of the outer ring 4 which is a stationary wheel, The inner end opening is blocked. That is, the cover 16a includes a cylindrical portion 41 having a large-diameter step portion 40 formed at the opening end, and a bottom plate portion 42 that closes the inner end opening of the cylindrical portion 41. The sensor unit 44 is held in the through hole 43 formed in a part of the bottom plate portion 42 in a state where it is hermetically sealed with the cover 16a.

The sensor unit 44 includes a processing circuit 46, a transmission circuit 47, a battery 48, and a determination circuit 57 in a holder 45 made of synthetic resin, in addition to the rotation detection sensor 39.
And embeds and supports the antenna 4 on the transmission side on the inner end face.
9 is installed. The processing circuit 46 is a rectifying / smoothing circuit for processing a part of the detection signal of the rotation detecting sensor 39 to obtain a direct current. That is, the processing circuit 46
Rectifies a part of the sinusoidal output signal (AC signal) output from the rotation detection sensor 39 as the encoder 19b rotates, operates the transmission circuit 47, and charges the battery 48. Get the direct current for. The reason for obtaining the direct current in this way is as follows.

In the case of the present invention, it is premised that the communication between the sensor unit 44 and the controller provided on the vehicle body side is performed wirelessly. Further, in the case of this example, a self-diagnosis is made in the sensor unit 44 to judge whether the operation of the rotation detection sensor 39 is proper or not. The electric power for wireless communication among these is supplied by the rotation detection sensor 39.
Electric power for self-diagnosis is obtained from the battery 48, but the power source of the transmitting circuit 47 is direct current.
Further, as the battery 48, a rechargeable battery such as a nickel-hydrogen battery or a nickel-cadmium battery is used so that the battery 48 does not reach the end of its life during the periodic inspection. On the other hand, in the case of this example, the encoder 1 is used as the rotation detection sensor 39.
The passive type is used, which generates power as the 9b rotates. That is, the rotation detection sensor 39 incorporated in the structure of this example includes an annular permanent magnet 50 magnetized in the radial direction, and a yoke 51 in which a magnetic metal plate such as a soft steel plate is formed in an annular shape with a substantially J-shaped cross section. , The yoke 51 and the permanent magnet 50.
And a coil 52 disposed in a portion surrounded by and. The yoke 51 has an inner peripheral end side in contact with or close to the inner peripheral surface of the permanent magnet 50, and an outer peripheral end side in close proximity to the inner peripheral surface of the outer diameter side cylindrical portion 38 of the encoder 19b. . Further, at the outer peripheral end portion of the yoke 51, the through hole 33a formed in the outer diameter side cylindrical portion 38,
The same number of notches 53, 53 as 33a are formed at equal pitches in the circumferential direction. Therefore, the outer peripheral end portion of the yoke 51 is formed in a comb shape. With such a configuration, the moment that a large amount of magnetic flux flows and the moment that a small amount of magnetic flux flows are alternately generated in the yoke 51 as the encoder 19b rotates, so that an alternating current is induced in the coil 52. There is.

In the case of this example, the coil 52 is
Part of this alternating current, which is the output signal of the rotation detection sensor 39 caused by the above, is processed by the processing circuit 46,
Obtain the above direct current. The direct current thus obtained operates the transmitting circuit 47 and charges the battery 48. It should be noted that, if necessary, the required DC power is sent from the battery 48 to the transmission circuit 47, and the transmission circuit 47
It may be used as a power source for operating the. That is, in the case of this example, the rotation detection sensor 39 has a function as a sensor for obtaining a signal for knowing the rotation speed of the wheel, and also supplies electric power for operating the transmission circuit 47 and a determination circuit 57 described later. It has a function as a generator for doing.

The rest of the output signal of the rotation detecting sensor 39 is directly sent to the transmitting circuit 47 without passing through the processing circuit 46. And this transmission circuit 4
7 is an output signal of the rotation detection sensor 39, which is a carrier wave,
The modulated wave is modulated by the modulator 54 to obtain a modulated wave that can be wirelessly transmitted. Then, the transmitting-side antenna 49 transmits the modulated wave to the receiving-side antenna 55 that communicates with the controller 36 provided on the vehicle body side. The signal received by the antenna 55 is demodulated by the demodulator 56 provided in the controller 36 to be restored to a signal representing the rotation speed, and used for controlling the ABS and TCS. The antenna 49 on the transmission side is the holder 45 made of the synthetic resin, which is exposed to the outside of the cover 16a.
It is supported on the inner end surface of the. Therefore, the radio wave transmitted from the antenna 49 is made of a steel plate such as SPCC, which is a metal member that shields the radio wave.
Therefore, the antenna 49 and the cover 16a are insulated from each other. As a result, the transmission from the antenna 49 to the receiving antenna 55 is efficiently performed.

Further, the judging circuit 57 is arranged so that the battery 48
The function diagnosis of the rotation detecting sensor 39 such as the presence / absence of disconnection of the coil 52 is performed based on the DC power supplied from the. That is, as shown in FIG. 3, the determination circuit 57 is fed from the antenna 55 on the controller 36 side to the antenna 49 on the sensor unit 44 side when the ignition switch is turned on to start the automobile. It starts based on the determination start command signal. Then, the determination circuit 57 diagnoses the function of the rotation detection sensor 39 by energizing the coil 52 and monitoring the energized state. Then, a signal representing the diagnosis result is sent to the antenna 49 on the sensor unit 44 side.
To the antenna 55 on the controller 36 side. Then, based on the diagnosis result, the controller 36 changes the signal sent from the rotation detection sensor 39 after the start of operation to A
It is determined whether or not the control is used for BS or TCS.

In this case, when it is determined that the coil 52 is not broken and a normal signal is sent from the rotation detecting sensor 39, the controller 36 causes the battery 48 to detect the rotation. The energization of the sensor 48 is stopped (power is turned off). In this case, the ABS or T
The control of CS is performed as usual. On the other hand, if the coil 52 is broken, the rotation detection sensor 3
When it is determined that the normal signal is not sent from 9, the controller 36 stops the functions of ABS and TCS and turns on the warning light in the driver's seat to warn the driver to repair. Emit. In this case as well, after the functions of ABS and TCS are stopped and an alarm is issued, the power supply from the battery 48 to the rotation detecting sensor 39 is stopped to prevent the battery 48 from being consumed. When the controller 36 does not receive the signal from the determination circuit 57, an abnormality in the wireless transmission system path or the like is considered, so the controller 36:
As in the case where the rotation detection sensor 39 fails, the AB
The function of S and TCS is stopped and an alarm is issued.

In any case, the magnetic field strength (strength of transmitted radio wave) emitted from the antenna 49 is the same as that of the antenna 4
It is suppressed to 35 μV / m or less in the part 3 m away from 9. The reason for this is to prevent interference in a limited frequency band. That is, even when using weak radio waves that are not regulated by the Radio Law, considering cost and efficiency,
The usable frequency band is limited. Then, by utilizing this limited frequency band, it is possible to prevent interference between the four sets of rotation speed detection devices incorporated in one automobile, and to drive other automobiles that may run next to each other. It is necessary to prevent interference with the rotation speed detection device incorporated in the. Interference prevention between four sets of rotation speed detection devices incorporated in one automobile can be dealt with by changing the frequency of the carrier wave of the radio wave relating to these four sets of rotation speed detection devices. Interference prevention between can not be dealt with by changing the frequency (because it is not known what frequency the car will use nearby). Therefore, it is necessary to shorten the reaching distance of the radio wave sent from the antenna 49 so that the radio wave sent from the antenna 49 does not reach the receiving side antenna 55 of another vehicle running nearby. In consideration of such a point, in the case of this example, the magnetic field strength is set to the antenna 49.
It is kept at 35 μV / m or less at a position 3 m away from the vehicle to prevent interference with other vehicles running nearby.

The processing circuit 46, the transmission circuit 47, and the determination circuit 57 are integrated into an IC (IC package or I
C bare chip) and each (or all circuits 4)
The IC chip (which includes 6, 47 and 57 together) is embedded and supported in the holder 45 during injection molding of the holder 45. The rotation detection sensor 39, the processing circuit 46, the transmission circuit 47, the determination circuit 57, the battery 48, and the antenna 49 are connected (conducted) prior to the injection molding of the holder 45. Therefore, the sensor unit 4
The respective components 46, 47, 57, and 48 of No. 4 are covered with the synthetic resin that constitutes the holder 45 and are hermetically sealed, so that water-tightness can be reliably maintained. The front half (left half in FIG. 1) of the sensor unit 44 and the encoder 19b are arranged in a closed space 58 which is shielded from the outside by the cover 16a. Therefore, it is possible to effectively prevent the occurrence of the inconvenience such as the foreign matter made of a magnetic material adhering to the encoder 19b and the accuracy of the rotation speed detection being deteriorated.

On the other hand, the base end portion (right end portion in FIG. 1) of the sensor unit 44 is the bottom plate portion 4 of the cover 16a.
2 is installed outside the closed space 58. Then, the processing circuit 46, the transmission circuit 47, the determination circuit 57,
The battery 48 is embedded and supported in the base end portion of the sensor unit 44. Therefore, the temperature rises of the processing circuit 46, the transmission circuit 47, the determination circuit 57, and the battery 48 are limited, and the processing circuit 46, the transmission circuit 47, and the determination circuit 57, which are electrical components for which it is difficult to ensure heat resistance. Therefore, it becomes easy to secure the durability of the battery 48.

In particular, as in this example, the rolling bearing unit 2
The structure in which the sensor unit 44 is attached to the inner end portion of the sensor is similar to the structure in which a sensor unit is attached to the axial center of the rolling bearing unit 2 as in the structure of a fourth example shown in FIG. The position of the unit 44 is a portion which is arranged on the outside in the radial direction of the rolling bearing unit 2 and is a great distance from a component (a disc rotor or a brake drum) of a braking device (not shown) which serves as a heat source and which is not shown. Therefore, the temperature of the environment in which the sensor unit 44 is used can be kept low, and the durability of the electrical components incorporated in the sensor unit 44 can be easily ensured.

Further, in the case of this example, the processing circuit 46,
The transmitter circuit 47, the determination circuit 57, and the battery 48 are provided at the inner end portion of the sensor unit 44 and outside the cover 16a on the axially inner side surface portion of the bottom plate portion 42. For this reason, the cover 16a can be used without making any change to the cover on which the conventional passive type rotation detection sensor is mounted, and the sensor unit 44 that constitutes the structure of this example can be mounted on this cover as it is. You can

In the case of this example, the rotation detection sensor 39
A passive type is used as this, and the rotation detection sensor 39 is provided with a power generation function. On the other hand, in addition to the passive type sensor, the active type rotation detecting sensor is added to the structure of the present example, and the active type rotation detecting sensor is built in the sensor unit. Only the power generation function is used, that is, rotation detection is performed by an active type sensor, and the passive type sensor is used as a power generation device for obtaining electric power for operating the active type sensor and the transmission circuit 47 and the determination circuit 57. It is also possible to do. In this case, even if the rotation speed of the wheels decreases and the amount of power generated by the passive sensor decreases, it is possible to transmit a signal indicating the rotation speed detected by the active sensor, so that the rotation speed at a lower speed. Detection is also possible. When the amount of power generated by the passive sensor decreases, the transmitter circuit 47 is driven by the electric power supplied from the battery 48. In this case, the determination circuit 5
7 determines the suitability of the operation of the active sensor.

According to the rolling bearing unit with a rotation speed detecting device of the present embodiment configured as described above, the harness 35 provided in the conventional structure shown in FIGS. Is omitted. For this reason, it is possible to prevent a failure due to wire breakage of the harness due to flying stones and the like, and to omit the harness itself and its wiring work, thereby achieving weight reduction and cost reduction. This point is the same as the case of the conventional structure described in the above-mentioned JP 2001-151090 A.

Particularly, in the case of the rolling bearing unit with the rotation speed detecting device of the present embodiment, since the judgment circuit 57, which is a self-diagnosis circuit for judging the presence / absence of abnormality of the rotation detection sensor, is provided, the ABS or TCS is provided. You can achieve safe operation of your car by preventing the malfunction of. Further, in the case of the rolling bearing unit with the rotation speed detecting device of the present example, the rotation detecting sensor 3
9, a transmission circuit 47 for wirelessly transmitting the detection signal detected by the rotation detection sensor 39, and the transmission circuit 4
7 and a processing circuit 46 for obtaining a direct current for charging the battery 48, the judgment circuit 57 and the battery 48 for forming the self-diagnosis circuit, and a single holder 4
Since the sensor unit 44 is held inside 5, the component management and the assembling work are facilitated, and the number of mounting brackets can be reduced, so that the cost and the weight can be easily reduced. That is, the components 47, 46, 57 and 48 are embedded and supported in the single holder 45 to form the sensor unit 44, which can be handled integrally. Therefore, only by mounting the sensor unit 44 on the bottom plate portion 42 of the cover 16a, the above-mentioned components 47, 46, 5
Installation work of 7, 48 is completed. Therefore, as described above, cost and weight can be reduced. In the above-described embodiment, the case where the signal transmission from the sensor unit side to the controller side is performed by wireless communication has been described, but the wireless communication performed in this part includes wireless optical communication (infrared, laser). (Including light), ultrasonic communication can also be adopted. In the case of this example, in order to enhance safety, self-diagnosis can be performed before traveling (while stopped),
The battery 48 is incorporated. That is, since the sensor unit 44 does not generate power during the stop, the battery 48 is required to perform self-diagnosis during the stop.

Next, FIGS. 4 to 6 show a second example of the embodiment of the present invention corresponding to claims 1 and 3. In the case of this example, the present invention is applied to a wheel supporting rolling bearing unit for driving wheels. Inner ring 6 externally fitted and fixed to the inner end portion of the hub 5b which is rotationally driven by the constant velocity joint 59.
The outer end of the encoder 19c, which is formed by forming a magnetic metal plate such as a mild steel plate into a cylindrical shape, is externally fitted and fixed to the inner end thereof by interference fitting. A large number of through holes 33b, 33b each having a slit shape are formed in a portion of the inner half portion of the encoder 19c projecting from the inner ring 6 at equal intervals in the circumferential direction, so that the outer periphery of the inner half portion is formed. The magnetic characteristics of the surface are changed alternately and at equal intervals in the circumferential direction.

On the other hand, at the inner end of the outer ring 4, a cover 16b is formed by bending a metal plate to form an annular shape as a whole.
Are fitted and fixed by interference fitting. This cover 16
The sensor unit 44a is held and fixed to a holding portion 60 formed by bulging the metal plate inward in the circumferential direction at a portion of b in the circumferential direction. This sensor unit 44a
Is a holder 45a made of synthetic resin, and the rotation detection sensor 3
9a, a processing circuit 46, and a transmission circuit 47 are embedded, and an antenna 49 is installed and fixed on the inner end surface of the holder 45a. The rotation detection sensor 39a is of a passive type, which is a combination of a stator made of a magnetic material, a permanent magnet, and a coil, and causes an alternating current in the coil as the encoder 19c rotates. In the case of this example, unlike the first example described above, the sensor unit 44a portion is not provided with a battery and a determination circuit. Instead, in the case of the present example, the determination circuit 57a is provided on the controller 36 side. To the determination circuit 57a, in addition to the signal indicating the rotation speed of the wheel transmitted from the rotation detection sensor 39a, a signal transmitted from another rotation detection sensor 61 provided in the transmission portion is input. The signals of both sensors 39a and 61 are compared. In the case of the present example, the rotation detection sensor 39 is operated by the determination circuit 57a as shown in FIG.
Whether or not there is an abnormality in a is determined.

That is, in the determination circuit 57a, after the ignition switch is turned on and the vehicle starts traveling, the output of the rotation detection sensor 39a becomes sufficiently high as the traveling speed increases (for example, the traveling speed is 3 km / h. The signal sent from the rotation detection sensor 39a is compared with the signal sent from the another rotation detection sensor 61 in the state (above). The signals sent from both the sensors 39a and 61 represent the traveling speed of the automobile (rotational speed of the drive wheels). Therefore, both of these sensors 39
The signals sent from a and 61 are converted into a comparable state (for example, a value indicating the vehicle speed), and the magnitudes are compared. When the difference between the signals sent from both the sensors 39a and 61 exceeds a preset predetermined value (for example, the difference between the two signals is 20% based on either one of them), It is determined that the rotation detection sensor is abnormal.
When it is determined that there is an abnormality, ABS or TCS
The function of is stopped and the warning light of the driver's seat is turned on to issue an alarm for urging the driver to repair. On the other hand, when it is determined that there is no abnormality, the ABS and TCS are made to function normally. Other configurations and operations are similar to those in the case of the first example described above. Since this example is a system that performs self-diagnosis after starting traveling, the sensor unit 4
The electric power generated by 4a can be used. Therefore, it is not necessary to install a battery in the sensor unit 44a, and the system is inexpensive accordingly.

Next, FIGS. 7 to 8 show a third example of the embodiment of the present invention corresponding to claims 1 and 4. In the case of this example, the permanent magnet 21a is used as the encoder 19d, as in the case of the first example of the conventional structure shown in FIG.
I am using the one that incorporates. Further, in the case of this example, an active type is used as the rotation detecting sensor 39b which constitutes the rotation speed detecting device in combination with the encoder 19d. The active type rotation detection sensor 39b processes a magnetic detection element such as a Hall element or a magnetoresistive element whose characteristics are changed according to a change (direction or amount) of magnetic flux, and an output waveform of this magnetic detection element. This is an IC chip with a waveform processing circuit (making a sine wave a rectangular wave). Therefore, the rotation detection sensor 39
The output signal from b becomes a rectangular wave that changes at a frequency proportional to the rotation speed of the rotating wheel.

Such an active type rotation detection sensor 3
9b can obtain a stable output regardless of the rotation speed of the rotating wheel (the output does not decrease when the rotation speed is low unlike the passive type), so that the rotation speed detection reliability is low. Can be improved. However, since the active rotation detecting sensor 39b does not generate power by itself and requires electric power to obtain a detection signal, it is necessary to supply electric power from the outside. In the case of the present invention, the sensor unit 44b including the rotation detection sensor 39b and the controller 3 provided on the vehicle body side.
Since it is premised that no harness is provided between the power supply unit 6 and the power supply unit 6, it is necessary to wirelessly supply the power.

For this reason, in the case of this example, a power receiving section 62 is provided at the base end of the holder 45b constituting the sensor unit 44b in addition to the processing circuit 46 and the transmission circuit 47, and the electric power receiving section 62 is provided on the vehicle body side. A power transmission unit 63 is installed. The power transmission unit 63 electromagnetically couples the power required for operating the rotation detection sensor 39b and the transmission circuit 47,
The light is wirelessly transmitted to the power receiving unit 62 by wireless light (including infrared rays and laser light), radio waves, ultrasonic waves, or the like. In this way, the electric power sent from the electric power transmitting unit 63 to the electric power receiving unit 62 is in a state in which the wireless power supply is taken into consideration, and therefore the rotation detecting sensor 3 is left as it is.
9b and the transmission circuit 47 cannot be operated.
Therefore, the processing circuit 46 supplies the electric power (by rectification or the like) to the rotation detection sensor 39b and the transmission circuit 47.
Is converted into an appropriate direct current to operate the motor and is sent to the rotation detection sensor 39b and the transmission circuit 47.

Further, in the case of this example, the controller 36 is configured as shown in FIG.
And determines whether or not the rotation detection sensor 39b is abnormal, and then determines whether or not the ABS or TCS is to function. That is, when it is determined that the signal sent from the rotation detection sensor 39b is abnormal, the ABS or TC is sent based on the signal sent from another rotation detection sensor 61 (see FIG. 5) installed in the transmission portion.
Control S. In this case, the ABS control is also limited to the drive wheels. Also, the left and right drive wheels are in the same control state,
Left and right independent control is not performed. The signal sent from the rotation detection sensor 39b is not used for this control. Then, when the abnormality of the signal sent from the rotation detecting sensor 39b is resolved within a preset predetermined time (for example, about 10 seconds), the rotation detecting sensor 3
Based on the signal sent from 9b, the ABS or T
Restart control of CS. On the other hand, if the above-mentioned abnormality is not resolved when the above-mentioned predetermined time has elapsed, the above-mentioned A
It has the functions of stopping the functions of BS and TCS and issuing an alarm to prompt the driver to repair.

When the present embodiment is carried out, the determination as to whether or not there is an abnormality in the rotation detecting sensor 39b is performed as in the above-mentioned first example or second example. In the case of such an example, ABS or TCS in the case where an interfering radio wave is input for a short time, for example, when passing in front of an automatic door.
It is possible to detect the abnormality of the rotation detection sensor 39b while ensuring the function of. As is clear from the above description, the structure of this example is preferably implemented in combination with the control described in the first example or the second example.

Next, FIG. 9 shows a fourth embodiment of the present invention.
An example is shown. In the case of this example, the outer ring 4 which is a stationary wheel
An attachment hole 64 is formed in a portion between the first and second outer ring raceways 11 and 12 at an axially intermediate portion thereof so as to penetrate the outer ring 4 in the radial direction. Then, in the mounting hole 64, a passive type stick-shaped sensor unit 44c similar to that used in the second example shown in FIG. 4 is inserted from the outside in the radial direction to the inside. On the other hand, at the inner end portion of another inner ring 65 that is externally fitted to the axially intermediate portion of the outer peripheral surface of the hub 5c that constitutes the rotating wheel together with the inner ring 6, tighten the encoder 19e inside the first inner ring raceway 8 The outer fitting is fixed by fitting or gluing. The encoder 19e is formed of a magnetic material in an annular shape as a whole, and has gear-like concavities and convexities formed on the outer peripheral surface thereof to change the magnetic characteristics of the outer peripheral surface alternately at equal intervals in the circumferential direction. ing. Further, in the case of this example, the first inner ring raceway 8 is provided on the outer peripheral surface of the other inner ring 65 which is fitted onto the intermediate portion of the hub 5c.

In the case of such a present example, the antenna 49 for transmitting a signal indicating the rotation speed is radially outside the outer peripheral surface of the outer ring 4, that is, a rolling member made of a metal member that shields radio waves. Since it exists outside the envelope of the bearing unit 2, the transmission from the antenna 49 to the receiving-side antenna 55 provided on the vehicle body side is performed well. Further, in the case of this example, since the rotation detection sensor 39c and the encoder 19e are arranged in the sealed space which is shielded from the outside by the seal rings 66 mounted on both ends of the outer ring 4 in the axial direction, It is possible to prevent foreign matter such as magnetic powder that has been wound up from the road surface from adhering to the rotation detecting portion including the rotation detecting sensor 39c and the encoder 19e, so that the reliability of rotation detection can be maintained for a long period of time. Other configurations and operations are the same as those of the first example shown in FIGS. 1 to 3 or the second example shown in FIGS.

[0043]

Since the rotation speed detecting device of the present invention is constructed and operates as described above, it has a structure capable of preventing a failure due to a disconnection, and effectively detects a failure of the rotation detecting sensor to ensure safe operation. Can contribute to. If further required, cost and weight can be further reduced.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing a signal transmission path.

FIG. 3 is a flowchart showing a state in which a failure determination is performed.

FIG. 4 is a sectional view showing a second example of the embodiment of the present invention.

FIG. 5 is a block diagram showing a signal transmission path.

FIG. 6 is a flowchart showing a state in which a failure determination is performed.

FIG. 7 is a sectional view showing a third example of the embodiment of the present invention.

FIG. 8 is a flowchart showing a state in which a failure determination is performed.

FIG. 9 is a sectional view showing a fourth example of the embodiment of the present invention.

FIG. 10 is a sectional view showing a first example of a conventional structure.

FIG. 11 is a partial cross-sectional view showing the second example.

[Explanation of symbols]

1 Rolling Bearing Unit with Rotational Speed Detection Device 2 Rolling Bearing Unit 3 Rotational Speed Detection Device 4 Outer Rings 5, 5a, 5b, 5c Hub 6 Inner Ring 7 First Flange 8 First Inner Ring Raceway 9 Second Inner Ring Raceway 10 Step Section 11 1st outer ring raceway 12 2nd outer ring raceway 13 2nd flange 14 Rolling element 15 Nut 16, 16a, 16b Cover 17, 17a Main body 18, 18a Fitting cylinder 19, 19a, 19b, 19c, 19d, 19e Encoder 20, 20a Support ring 21, 21a Permanent magnet 22 Insertion hole 23, 23a Sensor 24 Insertion part 25 Collar part 26 O-ring 27 Space 28 Locking cylinder 29, 29a Locking spring 30 Stud 31 Cylindrical part 32 Circular ring part 33, 33a , 33b through hole 34 caulked portion 35 harness 36 controller 37 inner diameter side cylindrical portion 38 outer diameter side cylindrical portion 39, 39a, 39b, 39c Roll detection sensor 40 Large-diameter step portion 41 Cylindrical portion 42 Bottom plate portion 43 Through holes 44, 44a, 44b, 44c Sensor units 45, 45a, 45b Holder 46 Processing circuit 47 Transmission circuit 48 Battery 49 Antenna 50 Permanent magnet 51 Yoke 52 Coil 53 Notch 54 Modulator 55 Antenna 56 Demodulators 57, 57a Judgment circuit 58 Sealed space 59 Constant velocity joint 60 Holding part 61 Other rotation detection sensor 62 Power receiving part 63 Power transmitting part 64 Mounting hole 65 Inner ring 66 Seal ring

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2F073 AA36 AB07 BB02 BC02 BC04                       BC05 CC01 CC08 EE01 FF02                       GG01 GG04 GG08                 3D046 BB01 BB28 BB29 HH36 MM06                       MM08 MM14 MM15

Claims (4)

[Claims] 1. A rolling bearing unit for supporting a wheel, comprising: a rotating wheel that rotates together with the wheel during traveling, the characteristics of a detected portion supported concentrically with the rotating wheel being alternately changed in the circumferential direction. An encoder and a rotation detection sensor supported by a portion that does not rotate in a state where the detection portion faces the detected portion and a rotation detection sensor that wirelessly transmits a detection signal of the rotation detection sensor to a controller provided on the vehicle body side. A rotation speed detecting device comprising a self-diagnosis circuit for determining whether or not there is an abnormality in the rotation detecting sensor. 2. The rotation detecting sensor generates electric power with a coil by magnetic flux change due to rotation of an encoder, and a self-diagnosis circuit is provided in a portion which does not rotate together with the rotation detecting sensor, and the rotation detecting sensor generates electric power. The self-diagnosis circuit is provided with a battery that is charged by electric power and a determination circuit that determines whether or not the rotation detection sensor is disconnected by using the battery as a power source. The rotation speed detection device according to claim 1, which has a function of sending a signal indicating the fact of disconnection to the controller when it is determined that the rotation speed is detected. 3. The rotation detecting sensor is for generating electric power by a coil due to a change in magnetic flux due to rotation of an encoder, and a self-diagnosis circuit installed in a transmission portion and a vehicle speed calculated based on a signal of the rotation detecting sensor. The rotation speed detection device according to claim 1, wherein when the difference from the vehicle speed calculated based on another rotation detection sensor exceeds a predetermined value set in advance, it is determined that the rotation detection sensor is abnormal. 4. When the controller determines that the signal sent from the rotation detection sensor is abnormal, the controller controls the antilock brake system based on the signal sent from another rotation detection sensor installed in the transmission portion. , If the abnormality of the signal sent from the rotation detection sensor is resolved within a predetermined time set in advance,
The control of the antilock brake system is restarted based on the signal sent from the rotation detection sensor, and if the abnormality is not resolved when the predetermined time has elapsed, the function of the antilock brake system is stopped and an alarm is issued. The rotation speed detection device according to any one of claims 2 to 3, which has a function of emitting a.