JP2003157485A - Transmission device of signal for showing state of wheel support part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a structure at low cost capable of measuring accurately the air pressure in a tire 38 during travelling, and hardly generating a disconnection fault in a circuit for transmitting a detection signal of a rotation detection sensor 51. SOLUTION: A radio signal transmitted from a first transmission antenna 41 of a pneumatic sensor unit 40 and a radio signal transmitted from a second transmission antenna 60 of a rotation sensor unit 56 are received by a single reception antenna 47. The detection signal of the rotation detection sensor 56 is transmitted to the body side by utilizing the reception antenna 47 indispensable for pneumatic measurement during travelling, to thereby reduce a part cost and an assembly cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention A signal transmission device for representing a state of a wheel supporting portion according to the present invention is provided with a signal representing an air pressure of a tire constituting a wheel of an automobile and a rolling bearing unit for supporting the wheel. It is used to send a signal indicating the status to a controller provided on the vehicle body side.

[0002]

2. Description of the Related Art By making it possible to detect the air pressure in a tire forming a wheel during traveling, in order to avoid the risk of bursts and the like associated with traveling while the air pressure is excessively reduced, for example, There is known a pressure estimation device in a tire as described in JP-A-11-20429. In the case of this conventional device, this air pressure is estimated by utilizing the fact that the spring constant of the tire changes due to the air pressure inside the tire. Further, since this air pressure changes depending on the temperature inside the tire, a temperature sensor provided in this tire portion measures this temperature and sends it to a controller on the vehicle body side to correct the estimated value of the air pressure. .
The detection signal of the temperature sensor is periodically wirelessly transmitted to the vehicle body side when the centrifugal force switch is turned on as the wheels rotate. The controller provided on the vehicle body side corrects the estimated value of the air pressure based on the temperature in the tire thus sent.

Further, a structure in which an air pressure detecting unit incorporating an air pressure sensor, a temperature sensor, a signal processing circuit, and a transmitter is mounted on a wheel supporting a tire is described in some documents. It is actually used in some car models. This conventional device employs a structure in which the air pressure and temperature in the tire detected by the air pressure sensor and the temperature sensor are wirelessly transmitted to a receiving antenna installed in the tire house of the body. In the case of this conventional structure, since the air pressure in the tire is directly measured,
The air pressure can be measured with high accuracy, and the performance of avoiding danger such as burst can be further improved.

On the other hand, an anti-lock brake system (A for ensuring the stability of the vehicle during braking or acceleration)
BS) and traction control system (TCS)
It has been widely practiced to detect the rotation speed of the wheel in order to control the rotation speed. In order to detect this rotation speed, a rolling bearing unit with a rotation speed detection device in which a rotation speed detection device is incorporated in a rolling bearing unit for rotatably supporting the wheel with respect to the suspension device is used to make the wheel as a suspension device. It is rotatably supported and detects the rotation speed of this wheel.

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. 4 has a rolling bearing unit 2 and a rotation speed detecting device 3 incorporated therein. The rolling bearing unit 2 among them has a hub 5 and an inner ring 6 which are rotating wheels rotatably supported on the inner diameter side of an outer ring 4 which is a stationary wheel. A wheel is provided on the outer peripheral surface of the outer end portion of the hub 5 (the left end portion of each drawing in which the rolling bearing unit is described, which is the end portion that is the outer side in the width direction when assembled to a vehicle. The same applies throughout the present specification). Is provided with a first flange 7 for mounting and a first inner ring raceway 8 is provided on the outer peripheral surface of the intermediate portion. The inner ring 6 has a second inner ring raceway 9 on its outer peripheral surface.
And is formed at a portion closer to the inner end of the hub 5 (referred to as an end that is the inner side in the width direction when assembled to a vehicle, the right end of each drawing showing the rolling bearing unit, the same throughout the specification). The external diameter is smaller than that of the portion where the first inner ring raceway 8 is provided, and is externally fitted to the step portion 10. 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 addition, in a 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 prevent the inner ring 6 from being separated from the hub 5.

The inner end (right end in FIG. 4) 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 as described above is fitted to the inner end portion of the outer ring 4 by fitting the front half portion (left half portion in FIG. 4) of the fitting cylinder 18 onto the inner end portion of the outer ring 4 by interference fitting to fix the outer ring 4 of the outer ring 4. The inner end opening is blocked.

On the other hand, in order to configure the rotation speed detecting device 3, 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 is separated from the second inner ring raceway 9, The encoder 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. 4), and the magnetized directions are alternately changed in the circumferential direction 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. 4), 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 (the right end portion in FIG. 4). A locking groove is formed on the outer peripheral surface of the intermediate portion of the insertion portion 24, and an O-ring 26 is formed in the locking groove.
Is locked.

On the other hand, 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. 4 to be closed), the insertion hole 22 is formed. A locking cylinder 28 is provided around the opening. The sensor 23 connects the insertion portion 24 to the locking tube 2
8 and the collar 25 is abutted against the front end surface of the locking cylinder 28, and is supported by the locking spring 28 in a coupled manner by a locking spring 29. Incidentally, regarding such a combined support structure by the locking spring 29, the above-mentioned Japanese Patent Laid-Open No. 11-23596.
Since it is described in detail in the publication and is not related to the gist of the present invention, detailed illustration and description thereof will be omitted.

When the rolling bearing unit 1 with the rotational 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 wheels. 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. 11-235 shown in FIG.
In the case of the second example of the conventional structure described in Japanese Patent Publication No. 96,
A cylindrical portion 31 is formed on the inner end of the hub 5a.
By forming a portion of the inner end surface of the inner ring 6 projecting from the tip portion of 1 in the diametrical outward direction, the swaged portion 34 is formed,
The caulking portion 34 joins and fixes the inner ring 6 to the hub 5a. If such a structure is adopted, compared to the structure in which the inner ring 6 is coupled and fixed to the hub 5 by the nut 15, as in the first example of the conventional structure shown in FIG.
Cost reduction can be achieved by reducing the number of parts and the labor required for assembly. In the case of the second example of the conventional structure shown in FIG. 5, the structure of the portion where the sensor 23a is coupled and supported by the locking spring 29a to the locking cylinder 28 provided in the main body 17 of the cover 16 is the above-described first structure. Different from the example. However, such a coupling and supporting structure using the locking spring 29a is also disclosed in the above-mentioned Japanese Patent Laid-Open No.
The detailed description and the description thereof are omitted because they are described in detail in Japanese Patent Publication No. 1-23596 and do not relate to the gist of the present invention. Further, in the case of the structure of the second example, the encoder 19a also differs from the case of the first example described above.
That is, the encoder 19a of this example has a cross-sectional shape formed by bending a magnetic metal plate such as a mild steel plate to form the circular ring portion 3
It has an L-shape having 2 and is formed into an annular shape as a whole. Then, a plurality of through holes 33 are radially formed in the circular ring portion 32, and the magnetic characteristics of the circular ring portion 32 are changed alternately and at equal intervals in the circumferential direction. In accordance with this, the internal structure of the sensor 23a is also different from that of the first example described above.

In each of the conventional structures shown in FIGS. 4 to 5, the detection signals of the sensors 23 and 23a are sent to the controller provided on the vehicle body side by the harness 35. 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 ring, 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.

[0014]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The above-mentioned first example of the conventional structure for obtaining the air pressure in the tire and the above-mentioned JP-A-200
The second example of the conventional structure for wirelessly transmitting the rotation speed signal to the vehicle body side, which is described in Japanese Patent Publication No. 1-151090, was considered separately from each other, and was not particularly considered in association with each other. Conventionally, a device that measures the air pressure in the tire and wirelessly transmits an air pressure signal representing the measured value to the vehicle body side,
The device combined with the device that wirelessly transmits the rotation speed signal is
It was neither implemented nor proposed.

Of course, it is possible to simultaneously carry out the first example and the second example of the above-mentioned conventional structure, but when they are simply combined, not only the cost of parts is increased but also the assembling work is troublesome. Become. That is, if the first and second examples of the above-described conventional structure are simply combined and a receiver for receiving a radio signal indicating the air pressure and a receiver for receiving a radio signal indicating the rotation speed are separately installed on the vehicle body side, the cost is reduced. The cost increase due to the provision of two receivers that are bulky and the cost increase due to the troublesome work of connecting these receivers and the controller by harnesses are added. As a result, it is inevitable that the overall cost will increase considerably. The signal transmission device representing the state of the wheel supporting portion of the present invention was invented in view of such circumstances.

[0016]

SUMMARY OF THE INVENTION A signal transmission device representing a state of a wheel supporting portion according to the present invention comprises a tire mounted on a wheel and indicates a state of a wheel supported by a suspension device through a rolling bearing unit. Of the signals that represent the signal that represents the air pressure in the tire, and at least the part that supports this wheel, selected from among a plurality of states of the part that is present on the wheel side of the suspension device, other than the air pressure. It is a transmission device of a signal representing a state of a wheel supporting portion, which transmits two or more kinds of signals to a vehicle body side and a wheel supporting portion state signal representing at least one kind of state. Such a device for transmitting a signal representing the state of the wheel supporting portion of the present invention is mounted on the wheel, and an air pressure signal transmitting unit for wirelessly transmitting a signal indicating the air pressure detected by the air pressure sensor, and a device other than the air pressure. A support portion state signal transmitter for wirelessly transmitting a wheel support portion state signal detected by a state sensor for detecting at least one state of the vehicle, and a single unit for receiving the support portion state signal and the signal representing the air pressure. And a receiver.

[0017]

In the case of the signal transmission device representing the state of the wheel supporting portion of the present invention configured as described above, since the signal representing the air pressure and the wheel supporting portion state signal are received by the single receiving portion, Since only one receiver is required, the cost of parts can be reduced, and the wiring work of the harness connecting the receiver and the controller can be easily performed. Even when a plurality of types of wireless signals representing different measurement values are received by a single receiving unit, if the frequency of the carrier wave of each of these wireless signals is changed, these wireless signals are received by the receiver side or controller side. It is possible to select and take out each of the above measured values separately.

[0018]

1 and 2 show a first example of an embodiment of the present invention corresponding to claims 1 to 3. still,
The feature of the present invention is that the wheel 3 is combined with the wheel 36.
The air pressure monitor 48 provided on the vehicle body side includes a signal representing the air pressure and temperature in the tire 38 constituting the vehicle 7, and a signal representing the detected values of the rotational speeds of the hub 5 and the inner ring 6 which are rotating wheels. And a structure for transmitting a signal indicating the state of the wheel supporting portion, which is wirelessly transmitted to the ABS controller 66. The structure and operation of the rolling bearing unit 2 portion for rotatably supporting the wheels 37 with respect to the suspension device are generally known from the past, including the first example of the conventional structure shown in FIG. Since the structure is the same as
The description will be omitted or simplified, and the characteristic part of the present invention will be mainly described below.

An air pressure sensor unit 40 is mounted on a part of the wheel 36 so that the air pressure and temperature inside the tire 38 can be measured freely. On the surface of the air pressure sensor unit 40, the first transmission antenna 41, which is the air pressure signal transmission unit described in claim 1, is installed. The air pressure sensor unit 40 includes, in addition to an air pressure sensor 42 for measuring the air pressure and a temperature sensor 43 for measuring the temperature, a transmission circuit (IC) 44 and a battery 45.
Is stored. The transmitter circuit 44 processes (modulates) the measurement signals of both the sensors 42 and 43 to bring them into a state in which wireless communication is possible, and includes a modulator 46. Then, the transmission circuit 44 modulates the carrier waves (of different frequencies) by the output signals of the both sensors 42, 43 by the modulator 46 to obtain separate modulated waves that can be wirelessly transmitted. Then, the first transmitting antenna 41 is
Each of these modulated waves receives the receiving antenna 47 provided on the vehicle body side.
Send to. In the case of this example, this receiving antenna 47
Is installed on the inner surface of the tire house 68.

The signal received by the receiving antenna 47 is demodulated by a demodulator provided in the control circuit of the air pressure monitor 48 provided on the vehicle body side, and restored to a signal showing air pressure and a signal showing temperature. Then, when the air pressure inside the tire 38 drops abnormally, the air pressure monitor 48 activates a warning means such as a warning light or a buzzer provided on the dashboard to issue a warning to the driver. Not only the air pressure inside the tire 38 but also the temperature is measured because the air pressure inside the tire 38, which is a closed space, changes depending on the temperature.
This is because the change due to the temperature is corrected by the Boyle-Charles law. In the illustrated example, the tire 38 is provided between the first transmitting antenna 41 and the receiving antenna 47.
Exists. Even in such an arrangement, there is no particular problem if the tire 38 does not have a structure that shields radio waves.
On the other hand, when the tire 38 has a steel belt that shields radio waves inside the outer peripheral wall,
The receiving antenna 47 is arranged on the inner surface of the tire house 68 in the lower right portion of FIG. 1, that is, at a portion directly facing the inner surface of the wheel 36, and the receiving antenna 47 is arranged between the receiving antenna 47 and the first transmitting antenna 41. Make sure that there is no shielding layer on. Of course, the first transmitting antenna 41 is also exposed on the inner peripheral surface of the wheel 36. Since it is not necessary to replace the battery 45 until the vehicle is scrapped, it is possible to intermittently measure the air pressure and temperature to suppress the consumption of the battery 45. Further, a calculation circuit is provided in the air pressure sensor unit 40, the temperature-corrected air pressure is obtained by calculation in the air pressure sensor unit 40, and only the signal representing the corrected air pressure is output from the first transmission antenna 41. It is also possible to transmit to the receiving antenna 47.

On the other hand, in order to detect the rotation speed of the wheel 37 during traveling, the nut 15 is pressed against the hub 5 while being externally fitted to the stepped portion 10 formed on the inner end of the hub 5. An encoder 19b is externally fitted and fixed to an inner end portion of an inner ring 6 that constitutes a rotary wheel together with the hub 5. In the case of this example, the encoder 19b is formed by bending a magnetic metal plate to have a crank shape in section and an annular shape as a whole. The inner diameter side cylindrical portion 49 and the outer diameter side cylindrical portion 50 are concentric with each other.
Have and. And in the outer diameter side cylindrical portion 50 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 50, which is the surface to be detected of the encoder 19b, are changed alternately at equal intervals in the circumferential direction.

In carrying out the present invention, the encoder 19b may be one in which the magnetic characteristics are alternately changed in the circumferential direction at equal intervals, and for example, the S pole and the N pole are provided 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 51 described later according to the difference in the properties of the encoder. That is, when an encoder having a permanent magnet is used, the rotation detection sensor 5
It is not necessary to incorporate a permanent magnet in 1, but in the case of using the encoder 19b made of only a magnetic material, on the sensor side,
As will be described later, it is necessary to incorporate a permanent magnet that is a 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 cylindrical shape is fitted into the opening of 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 the cylindrical portion 53 having the large-diameter step portion 52 formed at the opening end, and the bottom plate portion 54 that closes the inner end opening of the cylindrical portion 53. The rotation sensor unit 56 is held in a through hole 55 portion formed in a part of the bottom plate portion 54 in a state where the rotation sensor unit 56 is tightly sealed with the cover 16a.

The rotation sensor unit 56 embeds and supports a processing circuit 58 and a transmission circuit 59 in addition to the rotation detection sensor 51 in a holder 57 made of synthetic resin.
A second transmitting antenna 60 is installed on the inner end face. The processing circuit 58 is a rectifying / smoothing circuit for processing a part of the detection signal of the rotation detection sensor 51 to obtain a direct current. That is, the processing circuit 58 includes the encoder 19b.
A part of the sinusoidal output signal (AC signal) output from the rotation detection sensor 51 in accordance with the rotation of is rectified to obtain DC for operating the transmission circuit 59.

That is, in the rotation detecting sensor 51 incorporated in the structure of this example, an annular permanent magnet 61 magnetized in the radial direction and a magnetic metal plate such as a mild steel plate are formed into an annular shape with a substantially J-shaped cross section. The yoke 62, the yoke 62 and the permanent magnet 6
A coil 63 disposed in a portion surrounded by 1 and
It consists of and. The yoke 62 has an inner peripheral end side in contact with or close to the inner peripheral surface of the permanent magnet 61, and an outer peripheral end side in close proximity to the inner peripheral surface of the outer diameter side cylindrical portion 50 of the encoder 19b. . Further, at the outer peripheral end portion of the yoke 62, the through hole 33 formed in the outer diameter side cylindrical portion 50.
The same number of notches 64, 64 as a, 33a are formed at equal pitches in the circumferential direction. Therefore, the yoke 6
The outer peripheral edge portion of 2 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 62 as the encoder 19b rotates, thereby causing an alternating current in the coil 63. There is.

In the case of this example, the coil 63 is
A part of this alternating current, which is the output signal of the rotation detection sensor 51 caused by the above, is processed by the processing circuit 58,
Obtain the above direct current. The direct current thus obtained is used to operate the transmission circuit 59. That is, in the case of this example, the rotation detection sensor 51 functions as a sensor for obtaining a signal for knowing the rotation speed of the wheel, and also as a generator for supplying electric power for operating the transmission circuit 59. It has the function of. If necessary, a rechargeable battery such as a nickel-hydrogen battery may be held in the rotation sensor unit 56, and this battery may be charged by the direct current obtained by the processing circuit 58. If such a rechargeable battery is used in combination, the transmission circuit 59 can be operated sufficiently even when the rotation speed of the encoder 19b is low during low speed traveling and the amount of power generation of the rotation detection sensor 51 is small. Become.

The rest of the output signal of the rotation detecting sensor 51 is directly sent to the transmitting circuit 59 without passing through the processing circuit 58. And this transmitting circuit 5
9 is an output signal of the rotation detection sensor 51, which is a carrier wave,
The modulated wave is modulated by the modulator 65 to be a modulated wave that can be wirelessly transmitted. The modulated wave carrying the signal representing the rotation speed has a different frequency from the frequency of the modulated wave carrying the signal representing the air pressure and the frequency of the modulated wave carrying the signal representing the temperature. Then, the second transmitting antenna 6 on the transmitting side
0 transmits this modulated wave to the receiving antenna 47 provided on the vehicle body side. Of the signals received by the receiving antenna 47, the modulated wave carrying the signal representing the rotation speed is
Demodulation is performed by a demodulator provided in the ABS controller 66 provided on the vehicle body side to restore the signal representing the wheel rotation speed.
It is used to control the BS (or TCS). The signal representing the air pressure and the signal representing the temperature are demodulated by a demodulator provided in the air pressure monitor 48 provided on the vehicle body side and used for air pressure monitoring. The signal representing the rotation speed and the signal representing the air pressure and the signal representing the temperature are separated by the difference in the frequency of the modulated wave.

The second transmitting antenna 60 has the holder 5 made of synthetic resin, which is exposed to the outside of the cover 16a.
It is supported on the inner end surface of 7. Therefore, the radio wave transmitted from the second transmission antenna 60 is not shielded by the cover 16a made of a steel plate such as SPCC which is a metal member that shields the radio wave.
Further, the second transmission antenna 60 and the cover 16a are in an insulated state. As a result, the transmission from the second transmitting antenna 60 to the receiving antenna 47 is efficiently performed.

In any case, the magnetic field strength (strength of the transmitted radio wave) emitted from the first transmitting antenna 41 and the second transmitting antenna 60 is from the first and second transmitting antennas 41 and 60. It is suppressed to 35 μV / m or less at a portion 3 m away. The reason for this is to prevent interference in a limited frequency band. That is, even if a weak radio wave that is not regulated by the Radio Law is used, the available frequency band is limited in consideration of cost and efficiency. Then, by utilizing this limited frequency band, interference between four sets of air pressure detection devices and four sets of rotation speed detection devices, which are incorporated in one automobile, is prevented and the vehicles run next to each other. It is necessary to prevent possible interference with the rotation speed detection device incorporated in other automobiles.

To prevent interference between the four sets of air pressure detecting devices and the rotation speed detecting devices incorporated in one automobile, the frequency of the carrier wave of the radio wave relating to these four sets of air pressure detecting devices and rotation speed detecting devices is used. Can be dealt with by changing, but interference with other cars can not be prevented by changing the frequency (because we do not know what frequency the car using will come near). Therefore, the radio waves transmitted from the first and second transmission antennas 41 and 60 are shortened so that the radio waves transmitted from the first and second transmission antennas 41 and 60 can travel closer to each other. It is necessary not to reach the receiving antenna 47 of the automobile. In consideration of such a point, in the case of this example, the magnetic field strength is set to the first and second transmission antennas 4
It is kept at 35 μV / m or less in the part 3 m away from the 1, 60, to prevent interference with other cars running nearby.

The processing circuit 58 and the transmission circuit 59 are
IC (IC package or IC bare chip)
The respective IC chips (or all the circuits 58 and 59 together) are embedded and supported in the holder 57 at the time of injection molding. The rotation detection sensor 51, the processing circuit 58, the transmission circuit 59, and the second transmission antenna 60 are connected (conducted) prior to the injection molding of the holder 57. Therefore, the constituent members 51, 58, 59 of the rotation sensor unit 56 are in a state of being covered and sealed by the synthetic resin forming the holder 57, so that the watertightness can be reliably maintained. The first half of the rotation sensor unit 56 (the left half of FIG. 1) and the encoder 19b are arranged in a closed space 67 that 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 rotation sensor unit 5
The base end portion (right end portion in FIG. 1) of 6 is installed outside the closed space 67 with respect to the bottom plate portion 54 of the cover 16a. The processing circuit 58 and the transmission circuit 59 (and the battery, if a battery is provided) are embedded and supported in the base end portion of the rotation sensor unit 56. Therefore, the temperature rise of the processing circuit 58 and the transmission circuit 59 is limited, and it becomes easy to ensure the durability of the processing circuit 58 and the transmission circuit 59, which are electrical components whose heat resistance is difficult to ensure.

In particular, as in this example, the rolling bearing unit 2
The structure in which the rotation sensor unit 56 is attached to the inner end portion of the above is compared with the structure in which the sensor unit is attached to the central portion in the axial direction of the rolling bearing unit 2 as in the structure of the second example shown in FIG. The position of the rotation sensor unit 56 is a portion that is arranged radially outside the rolling bearing unit 2 and that is a large distance from a component (a disc rotor or a brake drum) of a braking device (not shown) that serves as a heat source and is a heat source. Therefore, this rotation sensor unit 56
It is possible to keep the operating environment temperature low, and it becomes easy to ensure the durability of the electrical components incorporated in the rotation sensor unit 56.

Further, in the case of this example, the processing circuit 58 and the transmission circuit 59 are provided on the inner end portion of the rotation sensor unit 56 and outside the cover 16a on the inner side surface portion of the bottom plate portion 54 in the axial direction. It is provided. Therefore, this cover 16a
As described above, the conventional passive type rotation detection sensor can be used without any change, and the rotation sensor unit 56 having the structure of this example can be attached to the cover as it is.

In the case of this example, the rotation detection sensor 51
A passive type is used as this, and the rotation detecting sensor 51 is provided with a power generation function. On the other hand, in addition to the passive type sensor, an active type rotation detecting sensor is added to the structure of this example, and the active type rotation detecting sensor is built in the sensor unit to generate power from the passive type sensor. It is possible to use only the function, that is, rotation detection is performed by an active type sensor, and the passive type sensor can be used as a power generation device for obtaining electric power for operating the active type sensor and the transmission circuit 59. is there. In this case, if a rechargeable battery is provided, even if the rotation speed of the wheels decreases and the amount of power generated by the passive sensor decreases, a signal indicating the rotation speed detected by the active sensor is transmitted. Therefore, it is possible to detect the speed of the lower speed rotation. When the amount of power generated by the passive sensor decreases, the transmitter circuit 59 is driven by the electric power supplied from the battery.

The rolling bearing unit with the rotational speed detecting device of the present embodiment constructed as described above omits the harness 35 provided in the conventional structure shown in FIGS. 4 to 5 by wirelessly transmitting the detection signal. is doing. Therefore, while preventing the failure due to the wire breakage of the harness due to flying stones,
By omitting the harness itself and its wiring work, weight reduction and cost reduction can be achieved. This point is related to the above-mentioned JP-A-200
This is the same as the case of the conventional structure described in JP-A-1-151090.

In particular, in the case of the signal transmitting device showing the state of the wheel supporting portion of this example, the wheel 36 which is a rotating portion.
From the vehicle body to the signal indicating the air pressure and the temperature and the signal indicating the rotation speed detected by the rotation speed detection device are received by a single receiving antenna 47 which is a single receiving unit. . For this reason, it is possible to reduce the cost of parts because only one receiving antenna 47 is required, and the wiring work of the harness that connects the receiving antenna 47 and the air pressure monitor 48 and the ABS controller 66, which are the controllers, respectively. Can be done easily. That is, these air pressure monitor 48 and AB
Since the S controller 66 can be installed in a single casing, the wiring work of the harness connecting the air pressure monitor 48 and the ABS controller 66 to the receiving antenna 47 can be performed at once, and the wiring can be performed. The work can be simplified.

Further, in the case of this example, the rotation detecting sensor 51, the transmitting circuit 59 for wirelessly transmitting the detection signal detected by the rotation detecting sensor 51, and the DC for operating the transmitting circuit 59. Since the rotation sensor unit 56 is formed by holding the processing circuit 58 and the processing circuit 58 in order to obtain the rotation sensor unit 56, component management and assembly work can be facilitated, and mounting brackets can be reduced, resulting in cost and weight reduction. Can be easily reduced. That is, each of the parts 51,
59 and 58 are embedded and supported in the single holder 57 to form the rotation sensor unit 56, which can be handled integrally. Therefore, only by mounting the rotation sensor unit 56 on the bottom plate portion 54 of the cover 16a, the work of mounting the above-mentioned components 51, 59, 58 is completed. Therefore, as described above, cost and weight can be reduced.
In the above embodiment, the case where the signal transmission from the first and second transmitting antennas 41 and 60 to the receiving antenna 47 is performed by wireless communication has been described. However, the wireless communication performed in this part is as follows. Wireless optical communication (including infrared and laser light) and ultrasonic communication can also be adopted.

Next, FIG. 3 shows a second embodiment of the present invention.
An example is shown. In the case of this example, the outer ring 4 which is a stationary wheel
A mounting hole 69 is formed in a portion between the first and second outer ring raceways 11 and 12 at an axially intermediate portion of the outer ring 4 so as to penetrate the outer ring 4 in the radial direction. Then, a rotation sensor unit 56a in which a passive type stick-shaped rotation detection sensor 51a is incorporated is inserted into the mounting hole 69 from the outer side to the inner side in the radial direction. The rotation detection sensor 51a includes a permanent magnet 61a magnetized in the axial direction (vertical direction in FIG. 3) and a pole piece made of a magnetic material in which one end face in the axial direction is abutted against one end face in the axial direction of the permanent magnet 61a. 70, and a coil 63a wound around the pole piece 70. Such a rotation detecting sensor 51a causes an alternating current in the coil 63a in response to a change in magnetic flux flowing in the pole piece 70.

On the other hand, an encoder 19c is tightly fitted on the outer peripheral surface of the intermediate portion of the hub 5b which constitutes the rotating wheel together with the inner ring 6.
Alternatively, it is fitted and fixed by adhesion. This encoder 19
Reference character c is a ring-shaped member made of a magnetic material, and gear-like irregularities are formed on the outer peripheral surface of the outer peripheral surface, and the magnetic characteristics of the outer peripheral surface are changed alternately at equal intervals in the circumferential direction. . The other axial end surface of the pole piece 70 of the rotation detection sensor 51a is closely opposed to the outer peripheral surface of the encoder 19c. When the hub 5b rotates together with the wheels,
The amount of magnetic flux flowing in the pole piece 70 changes as the irregularities on the outer peripheral surface of the encoder 19c change, and an alternating current having a frequency proportional to the rotation speed is induced in the coil 63a.

Further, in the case of the present example, in addition to the rotation detecting sensor 51a, the vibration sensor 71 and the temperature sensor are provided in the holder 57a which embeds the rotation detecting sensor 51a and constitutes the rotation sensor unit 56a. 72 and 72 are held. Of these, the vibration sensor 71 detects the vibration generated during the operation of the rolling bearing unit 2a via the holder 57a and the outer ring 4. In addition, the temperature sensor 72
Detects the temperature of the rolling contact portion of the outer ring 4. For this reason, in the illustrated example, the temperature sensor 72 is installed in a portion as close as possible to the first outer ring raceway 11 formed on the inner peripheral surface of the outer ring 4, and the detection part thereof is made of the synthetic resin holder 57a. The outer ring 4 is exposed to the outer peripheral surface thereof and is in direct contact with or close to the outer ring 4. Therefore, the temperature sensor 72 accurately (sensitively) measures the temperature of the outer ring 4.

Incidentally, as shown in the figure, the rotation sensor unit 56a
When the rolling bearing unit 2a is attached to the suspension device and is incorporated in the vertically upper portion, the temperature sensor 72 is close to the load zone of the rolling elements constituting the rolling bearing unit 2a and the temperature rises most. It will be located in the part where it is easy to do. Therefore, the detection sensitivity of the temperature sensor 72 is improved. Further, the rotation sensor unit 56a
From the state shown in the drawing, the temperature sensor 72 is arranged equidistant from the double-row rolling bearings by mounting the rotation sensor unit 56a in a state of being rotated 90 degrees in the circumferential direction about the axis of the rotation sensor unit 56a itself. The temperature detection sensitivities of the double-row rolling bearings can be made equal to each other.

Further, in order to obtain a direct current by rectifying a part of the output of the rotation detecting sensor 51a to a portion exposed from the outer peripheral surface of the outer ring 4 at the base end portion (upper end portion in FIG. 3) of the holder 57a. Embedded in and supporting a processing circuit 58, a remaining output of the rotation detecting sensor 51a, and a transmitting circuit 59 for processing the detection signals of the vibration sensor 71 and the temperature sensor 72 into a state capable of wireless transmission. . Also, the holder 57a
A second transmission antenna 60 for transmitting the radio signal processed by the transmission circuit 59 to the reception antenna 47 mounted on the inner surface of the tire house 68 is installed on the base end surface (upper end surface of FIG. 3). There is.

In the case of the present example as described above, the second transmitting antenna 60 has an envelope of the rolling bearing unit 2a which is radially outside of the outer peripheral surface of the outer ring 4, that is, a metal member which shields radio waves. Since it exists outside the line, the transmission from the second transmitting antenna 60 to the receiving antenna 47 provided on the vehicle body side is performed well. In the case of this example,
The seal rings 73, 73 in which the rotation detection sensor 51a and the encoder 19c are attached to both axial end portions of the outer ring 4 described above.
Since it is placed in a closed space that is shielded from the outside by a foreign matter such as magnetic powder or the like, which is wound up from the road surface, is prevented from adhering to the rotation detecting portion including the rotation detecting sensor 51a and the encoder 19c. Therefore, the reliability of rotation detection can be maintained for a long period of time.

On the other hand, the wheel 36 constituting the wheel 37 supported by the hub 5b is equipped with the same air pressure sensor unit 40 as in the case of the above-mentioned first example, and the tire 38 detected by this air pressure sensor unit 40 is mounted. The signal representing the air pressure inside and the signal representing the temperature are freely transmitted to the receiving antenna 47 by the first transmitting antenna 41. The configuration of the air pressure sensor unit 40 portion is the same as in the case of the first example described above.

Further, in the case of the present embodiment, the hub 5b for driving wheels is used. For this reason, a spline hole 74 is provided at the center of the hub 5b. The inner ring 6 fitted on the inner half of the hub 5b is attached to the hub 5b.
The inner ring 6 is fixed to the hub 5b by being held down by the caulking portion 75 formed at the inner end portion of the. And
A disk rotor made of carbon-carbon composite material (C-C composite) is coupled and fixed to the first flange 7 provided on the outer peripheral surface of the hub 5b. As the disk rotor made of this carbon-carbon composite material, a disk rotor having a smaller diameter than that of a normal cast iron disk rotor is used.

In the case of the signal transmitting device representing the state of the wheel supporting portion of the present embodiment configured as described above, from the first transmitting antenna 41 provided in the air pressure sensor unit 40 portion to the receiving antenna 47, A signal representing the air pressure and temperature inside the tire 38 is wirelessly transmitted. In addition, the second transmission antenna 6 provided in the rotation sensor unit 56a portion
From 0 to the receiving antenna 47, a signal representing the rotation speed of the wheel 37 and the outer ring 4 constituting the rolling bearing unit 2a
A signal indicating the vibration of the portion and a signal indicating the temperature are wirelessly transmitted.

The signal representing the air pressure and temperature in the tire 38 and the signal representing the rotation speed of the wheel 37 are the same as in the case of the first example described above, and the air pressure monitor 48 or A.
It is sent to the BS controller 66 and used for monitoring the air pressure in the tire 38 or for controlling the ABS.

On the other hand, the signal representing the vibration of the outer ring 4 portion detected by the vibration sensor 71 is used to detect an abnormality in the rotation support portion of the wheel 37 due to the rolling bearing unit 2a. The abnormality of the rotation support portion detected by the vibration sensor 71 means the rolling contact surface of the rolling bearing unit 2a, especially the first and second inner ring raceways 8 and 9, and the first and second outer ring raceways 11. The rolling bearing unit 2a is damaged, such as peeling off at 12, or a part of the suspension device supporting the rolling bearing unit 2a is damaged, or the wheel 36 of the wheel 37.
Alternatively, if the vibration occurs due to the damage, such as that caused by the damage of the tire 38, it can be detected. The presence or absence of such an abnormality in the rotation support portion is determined by the reception antenna 4
7 is received and demodulated by the demodulator, and is judged by the vibration judging device 76 which has received the signal representing the vibration of the outer ring 4 portion. In this case, if a large vibration continues for a certain amount of time (for example, several seconds or more), it is determined that there is an abnormality,
Warnings are issued from the warning lights and buzzers installed on the dashboard. The reason for this is that it is not possible to determine that there is an abnormality due to vibration applied to the outer ring 4 portion when the vehicle is traveling on a rough road or the like in a road surface state.

Further, the temperature of the outer ring 4 portion detected by the temperature sensor 72 is deteriorated in durability of the rolling bearing unit 2a as the temperature inside the rolling bearing unit 2a is abnormally increased. It is used to prevent
That is, in the case of this example, carbon-
A disk rotor made of carbon composite material is provided. This disk rotor made of carbon-carbon composite material has a small diameter, and at the time of braking, the temperature of the friction surface is increased to secure the braking force.
Higher than cast iron rotor. The smaller diameter leads to a shorter distance between the friction surface and the main part of the rolling bearing unit 2a, and the remarkable rise in temperature leads to a larger amount of heat transferred to the rolling bearing unit 2a. For this reason, the temperature rise of the rolling bearing unit 2a portion becomes more remarkable as compared with the case where a normal cast iron disc rotor is used.

On the other hand, in the rolling bearing unit 2a,
The grease filled for lubricating the rolling contact surface deteriorates at a high temperature (for example, 170 ° C. or higher). Therefore, the temperature rise determiner 77, which has received the signal representing the temperature of the outer ring 4 portion received by the receiving antenna 47 and demodulated by the demodulator, has the temperature of the outer ring 4 portion equal to or higher than a predetermined value (for example, 160 ° C. or higher). ), It is judged that there is something wrong and a warning is issued from the warning light or buzzer installed on the dashboard. In the case of this example, the rotation sensor unit 56a
Is provided at the central portion of the outer ring 4 in the axial direction, it is possible to accurately detect the vibration and the temperature rise, and effectively detect the abnormality of the rotation support portion and the temperature rise of the rolling bearing unit 2a.

As described above, when the disk rotor made of carbon-carbon composite material is used, the rolling bearing unit 2a described above is used.
Are exposed to a higher temperature environment. On the other hand, as in this example, the temperature sensor 72 is used for the rolling bearing unit 2a.
If the temperature of the rolling bearing unit 2a is measured, the deterioration of the grease can be detected early before the rolling bearing unit 2a is seriously damaged such as seizure, and the serious damage can be prevented. it can. As for warning means such as a warning light and a buzzer provided on a dashboard or the like, it is costly to individually display the presence or absence of abnormality based on signals such as air pressure, vibration, and temperature for each of the four wheels. Not only that, but the number of check items for the driver is increased, which is not preferable. Therefore, as for the above-mentioned warning means, one is provided for each of air pressure, vibration, and temperature, and a warning is issued if any one of the four wheels is abnormal. In this case, a repair shop can check which of the four wheels has an abnormality. For this reason, it is preferable that the air pressure monitor 48, the vibration determiner 76, and the temperature increase determiner 77 are provided with storage means for storing a history of abnormality, such as a memory. In addition, it is possible to warn of all abnormalities in air pressure, vibration, and temperature with one warning means.
It is also possible to allow a repair shop to check which abnormality has occurred for which wheel.

[0053]

Since the device for transmitting the signal indicating the state of the wheel supporting portion of the present invention is constructed and operates as described above, the tire air pressure can be accurately measured during running and the rotational speed detecting device is disconnected. It is possible to realize a structure capable of preventing a failure due to the above at low cost.

[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 sectional view showing a second example of the embodiment of the present invention.

FIG. 4 is a sectional view showing a first example of a conventional structure.

FIG. 5 is a partial cross-sectional view showing the second example.

[Explanation of symbols]

1 Rolling bearing unit with rotational speed detector 2, 2a Rolling bearing unit 3 Rotational speed detector 4 outer ring 5, 5a, 5b hub 6 inner ring 7 First flange 8 First inner ring raceway 9 Second inner ring raceway 10 steps 11 First outer ring raceway 12 Second outer ring raceway 13 Second flange 14 rolling elements 15 nuts 16, 16a, 16b cover 17, 17a body 18, 18a Fitting tube 19, 19a, 19b, 19c encoder 20, 20a Support ring 21 Permanent magnet 22 insertion hole 23, 23a sensor 24 Insert 25 collar part 26 O-ring 27 spaces 28 Locking cylinder 29, 29a Locking spring 30 studs 31 Cylindrical part 32 circle 33, 33a through hole 34 Caulking part 35 harness 36 wheels 37 wheels 38 tires 40 Air pressure sensor unit 41 First transmitting antenna 42 Air pressure sensor 43 Temperature sensor 44 Transmitting circuit 45 batteries 46 modulator 47 receiving antenna 48 Air pressure monitor 49 Inner diameter side cylindrical part 50 Outer diameter side cylindrical part 51, 51a rotation detection sensor 52 Large diameter step 53 Cylindrical part 54 Bottom plate 55 through hole 56, 56a Rotation sensor unit 57, 57a holder 58 processing circuit 59 Transmission circuit 60 Second transmitting antenna 61, 61a Permanent magnet 62 York 63, 63a coil 64 cutout 65 modulator 66 ABS controller 67 closed space 68 tire house 69 mounting hole 70 pole pieces 71 Vibration sensor 72 Temperature sensor 73 seal ring 74 Spline hole 75 Caulking part 76 Vibration judge 77 Temperature rise judging device

Claims (3)

[Claims] 1. A signal, which is formed by mounting a tire on a wheel and which is supported by a suspension device through a rolling bearing unit, of a signal representing the air pressure in the tire and at least a signal supporting the wheel. Two or more kinds of signals, a wheel supporting part state signal representing at least one kind of state other than pneumatic pressure, which is selected from a plurality of states of a portion existing on the wheel side of the suspension device. Is a transmission device of a signal representing the state of a wheel supporting portion, which is mounted on the wheel, and an air pressure signal transmitting unit for wirelessly transmitting a signal representing the air pressure detected by an air pressure sensor, A support section status signal transmission unit for wirelessly transmitting a wheel support section status signal detected by a status sensor for detecting at least one state other than the air pressure, and this support section status signal. And a single receiver for receiving the signal representing the air pressure, and a device for transmitting the signal representing the state of the wheel supporting portion. 2. A wheel supporting portion state signal representing at least one state other than pneumatic pressure constitutes a rolling bearing unit and represents a rotational speed signal of a rotating wheel that rotates together with the wheel during traveling, and the rolling bearing. Transmission of a signal representing the state of the wheel support portion according to claim 1, which is one or more kinds of signals selected from a vibration signal representing the vibration of the unit and a temperature signal representing the temperature of the rolling bearing unit. apparatus. 3. A wheel is equipped with a temperature sensor for measuring the temperature inside the tire, in addition to an air pressure sensor for measuring the air pressure inside the tire, and the air pressure signal transmitting section is provided with:
In addition to the signal indicating the air pressure, the tire temperature signal indicating the temperature is also wirelessly transmitted, and the signal transmission device indicating the state of the wheel supporting portion according to claim 1.