JP2007292233A - Wheel bearing with sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wheel bearing with a sensor capable of compactly mounting the sensor for load detection on a vehicle, sensitively detecting the load on a wheel and reducing costs in mass-production. <P>SOLUTION: In the wheel bearing mounted in a knuckle 16 of a suspension device by interposing double-row rolling elements 3 between an outer member 1 and an inner member 2 so as to freely rotatably support a wheel with respect to a vehicle body, a sensor unit 21 consisting of a sensor mounting member 22 and one or more displacement sensor 23 mounted in the sensor mounting part 22 is mounted in the knuckle 16. The sensor mounting part 22 is provided with at least one contact fixing part 22a with respect to the knuckle 16. The displacement sensor 23 measures the displacement of the surface of a fixed side member of the outer member 1 and an inner member 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sensor-equipped wheel bearing with a built-in load sensor for detecting a load applied to a bearing portion of the wheel.

  2. Description of the Related Art Conventionally, there is a wheel bearing provided with a sensor for detecting the rotational speed of each wheel for safe driving of an automobile. Conventional measures to ensure driving safety of general automobiles are carried out by detecting the rotational speed of the wheels of each part, but the rotational speed of the wheels is not sufficient, and it is further safer by using other sensor signals. It is required that the surface can be controlled.

  Therefore, it is conceivable to control the attitude from the load acting on each wheel during vehicle travel. For example, a large load is applied to the outer wheel in cornering, and the load applied to each wheel is not uniform. Further, even when the load is uneven, the load applied to each wheel becomes uneven. For this reason, if the load applied to the wheel can be detected at any time, based on the detection result, the suspension and the like are controlled in advance, thereby controlling the posture during vehicle travel (preventing rolling during cornering, preventing the front wheel from sinking during braking, It is possible to prevent subsidence due to uneven load load. However, there is no appropriate installation location of a sensor that detects a load acting on the wheel, and it is difficult to realize posture control by load detection.

  In addition, when steer-by-wire is introduced in the future, and the system is such that the axle and the steering are not mechanically coupled, it is required to detect the axle direction load and transmit the road surface information to the handle held by the driver.

As a response to such a demand, a wheel bearing has been proposed in which a strain gauge is attached to the outer ring of the wheel bearing to detect the strain (for example, Patent Document 1).
Special table 2003-530565 gazette

  The outer ring of the wheel bearing is a part that has a rolling surface and requires strength, and is a bearing part that is produced through complicated processes such as plastic working, turning, heat treatment, and grinding. When a strain gauge is attached to the outer ring as in Patent Document 1, there is a problem that productivity is poor and the cost for mass production is high. Moreover, it is difficult to detect the load applied to the wheel with high sensitivity, and when the detection result is used for attitude control during vehicle travel, the accuracy of the control becomes a problem.

  An object of the present invention is to provide a sensor-equipped wheel bearing in which a load detection sensor can be compactly installed in a vehicle, the load applied to the wheel can be detected with high sensitivity, and the cost during mass production is low.

  The sensor-equipped wheel bearing according to the present invention includes an outer member having a double row rolling surface formed on the inner periphery, an inner member having a rolling surface facing the rolling surface of the outer member, In a wheel bearing having a double row rolling element interposed between both rolling surfaces and attached to a knuckle of a suspension device to rotatably support a wheel with respect to a vehicle body, the sensor mounting member and the sensor mounting member A sensor unit comprising at least one displacement sensor attached is attached to the knuckle, the sensor attachment member has at least one contact fixing portion with respect to the knuckle, and the displacement sensor The displacement of the surface of the fixed side member of the member and the inner member is measured.

When a load is applied to the rotation-side member as the vehicle travels, the fixed-side member is deformed via the rolling elements, and the deformation changes the distance between the fixed-side member and the sensor unit. The displacement sensor provided in the sensor unit detects the distance between the fixed member and the sensor unit. From the detection result, the displacement of the stationary member is obtained. If the relationship between the displacement and the load is obtained in advance through experiments and simulations, the load applied to the wheel and the steering moment acting on the wheel bearing can be detected from the output of the displacement sensor. The steering moment is a moment applied to the wheel bearing when the vehicle travels on a curved path. Further, the detected load and steering moment can be used for vehicle control of the automobile.
Since the sensor attachment member of the sensor unit is attached to the knuckle by the contact fixing portion, the sensor attachment member hardly deforms even when the rotation side member is deformed. Since the displacement sensor attached to the sensor attachment member measures the displacement of the surface of the fixed member, the measurement accuracy of the displacement is high, and the detection accuracy of the load applied to the vehicle body detected from the measurement value is also high.
Since this wheel bearing has a structure in which a sensor unit comprising a sensor mounting member and a displacement sensor mounted on the sensor mounting member is mounted on the knuckle, the load detection sensor can be mounted compactly on the vehicle. Since the sensor attachment member is a simple part that can be attached to the knuckle, attaching a displacement sensor to the sensor attachment member makes it possible to achieve excellent mass productivity and reduce costs.

The displacement sensor can measure the deformation of the fixed member by measuring the displacement of the surface of the fixed member of the outer member and the inner member. In that case, the displacement of the outer peripheral surface of the stationary member is greatly deformed in the radial direction compared to other portions of the stationary member due to the external force acting on the stationary member or the acting force between the tire and the road surface. It is preferable to measure.
If the displacement of a portion that greatly deforms in the radial direction is measured, the load and the steering moment can be measured with high sensitivity as the displacement.

  The fixed member can be an outer member. In that case, the displacement of the outer peripheral surface of the outer member is measured by the displacement sensor of the sensor unit.

  In this invention, the said sensor unit can be attached to the upper part or the lower part of the said knuckle, or both upper and lower sides. In this case, the load applied to the vehicle can be calculated from the output of the displacement sensor of the sensor unit.

When the sensor unit is mounted at the above location, it is preferable to provide an acting force estimating means for estimating an external force acting on the wheel bearing or an acting force between the tire and the road surface based on the output of the displacement sensor.
By using the external force acting on the wheel bearing obtained by the acting force estimation means or the acting force between the tire and the road surface for vehicle control of the automobile, fine vehicle control is possible.

  Moreover, in this invention, you may make it attach the said sensor unit to the front part in the vehicle advancing direction of the said knuckle, the rear part, or both front and rear. In this case, the steering moment acting on the wheel bearing can be calculated from the output of the displacement sensor of the sensor unit.

When the sensor unit is mounted at the above location, it is preferable to provide a moment estimation means for estimating the steering moment acting on the wheel bearing by the output of the displacement sensor.
By using the steering moment acting on the wheel bearing obtained by the moment estimating means for vehicle control of the automobile, fine vehicle control is possible.

  The sensor unit may be plural. When a plurality of sensor units are provided, it is possible to measure displacements at a plurality of locations on the fixed side member, so that it is possible to detect a load with high accuracy.

A temperature sensor may be provided on the sensor mounting member.
Since the temperature of the wheel bearing and the knuckle changes during use, the temperature change affects the deformation of the sensor mounting member or the operation of the displacement sensor. It also has the same effect on changes in ambient environmental temperature. By correcting the temperature characteristics of the displacement sensor based on the output of the temperature sensor, it is possible to detect a load with high accuracy.

The sensor mounting member may be provided with at least one of an acceleration sensor and a vibration sensor.
When various sensors such as an acceleration sensor and a vibration sensor are attached to the sensor mounting member in addition to the displacement sensor, the load and the state of the wheel bearing can be measured at one place, and wiring and the like can be simplified. it can.

  As the displacement sensor, an eddy current sensor, a magnetic sensor, an optical sensor, an ultrasonic sensor, a contact sensor, or the like can be used. Any other type of sensor may be used as long as it can detect displacement. An appropriate sensor may be selected in accordance with various conditions.

A sensor signal processing circuit unit having a sensor signal processing circuit for processing the output signal of the displacement sensor may be provided in the vicinity of the sensor unit.
Providing a sensor signal processing circuit unit in the vicinity of the sensor unit can simplify the wiring work from the sensor unit to the sensor signal processing circuit unit. Further, the sensor signal processing circuit unit can be installed more compactly than when the sensor signal processing circuit unit is provided in a place other than the wheel bearing.

  The sensor-equipped wheel bearing according to the present invention includes an outer member having a double row rolling surface formed on the inner periphery, an inner member having a rolling surface facing the rolling surface of the outer member, In a wheel bearing having a double row rolling element interposed between both rolling surfaces and attached to a knuckle of a suspension device to rotatably support a wheel with respect to a vehicle body, the sensor mounting member and the sensor mounting member A sensor unit comprising at least one displacement sensor attached is attached to the knuckle, the sensor attachment member has at least one contact fixing portion with respect to the knuckle, and the displacement sensor Since the displacement of the surface of the fixed side member among the members and the inward members is measured, a load detection sensor can be compactly installed in the vehicle, and the load applied to the wheel can be detected with high sensitivity. Since the sensor attachment member is a simple part that can be attached to the knuckle, by attaching a displacement sensor to the sensor attachment member, the sensor attachment member can be excellent in mass productivity, and the cost can be reduced.

  An embodiment of the present invention will be described with reference to FIGS. This embodiment is a third generation inner ring rotating type and is applied to a wheel bearing for driving wheel support. In this specification, the side closer to the outer side in the vehicle width direction of the vehicle when attached to the vehicle is referred to as the outboard side, and the side closer to the center of the vehicle is referred to as the inboard side.

  This sensor-equipped wheel bearing includes an outer member 1 having a double row rolling surface 3 formed on the inner periphery, an inner member 2 having a rolling surface 4 opposed to each of the rolling surfaces 3, and these It is comprised by the double row rolling element 5 interposed between the rolling surfaces 3 and 4 of the outer member 1 and the inner member 2. This wheel bearing is a double-row angular ball bearing type, and the rolling elements 5 are made of balls and are held by a cage 6 for each row. The rolling surfaces 3 and 4 are arc-shaped in cross section, and each rolling surface 3 and 4 is formed so that the contact angle is outward. Both ends of the bearing space between the outer member 1 and the inner member 2 are sealed by sealing devices 7 and 8, respectively.

  The outer member 1 is a fixed side member, and is formed as an integral part as a whole. The outer member 1 has a flange 1a for attaching to a knuckle 16 extending from a suspension device (not shown) of the vehicle body on the outer peripheral portion, and a vehicle body having internal threads cut at a plurality of locations in the circumferential direction of the flange 1a. A mounting hole 14 is provided. On the other hand, a knuckle bolt insertion hole 17 with a step is provided at a position corresponding to the vehicle body mounting hole 14 in the knuckle 16. The outer member 1 and the knuckle 16 are fixedly integrated with each other by screwing the knuckle bolt 18 inserted from the knuckle bolt insertion hole 17 side into the vehicle body mounting hole 14.

  The inner member 2 serves as a rotation side member, and includes a hub wheel 9 having a hub flange 9a for wheel mounting, and an inner ring 10 fitted to the outer periphery of the inboard side end of the shaft portion 9b of the hub wheel 9. And become. The hub ring 9 and the inner ring 10 are formed with the rolling surfaces 4 of the respective rows. An inner ring fitting surface 12 having a small diameter with a step is provided on the outer periphery of the inboard side end of the hub wheel 9, and the inner ring 10 is fitted to the inner ring fitting surface 12. A through hole 11 is provided at the center of the hub wheel 9. The hub flange 9a is provided with press-fitting holes 15 for hub bolts 19 at a plurality of locations in the circumferential direction. In the vicinity of the base portion of the hub flange 9a of the hub wheel 9, a cylindrical pilot portion 13 for guiding a wheel and a braking component (not shown) protrudes toward the outboard side.

  A sensor unit 21 shown in FIG. 3 is attached to the upper portion of the knuckle 16. The sensor unit 21 includes an elongated sensor mounting member 22 whose tip is bent like a bowl, and a displacement sensor 23 attached to the tip of the sensor mounting member 22. The base portion of the sensor attachment member 22 is a contact fixing portion 22a for attachment to the knuckle 16.

  As shown in FIGS. 1 and 2, the sensor unit 21 is attached to the knuckle 16 by fixing the contact fixing portion 22 a of the sensor attachment member 22 to the tip surface of the knuckle 16 with an adhesive or the like. In this embodiment, the displacement sensor 23 is a non-contact type sensor such as an eddy current type, and the displacement sensor 23 measures the radial displacement of the outer circumferential surface of the outer member 1. 1 is attached to the sensor unit 21 with a predetermined interval from the outer peripheral surface. The axial direction position of the outer member 1 that opposes the displacement sensor 23 is, for example, in the vicinity of the rolling surface 3 in the outboard side row or on the outboard side of the rolling surface 3. The portion of the outer member 1 on the outboard side with respect to the rolling surface 3 is relatively greatly deformed in the radial direction with respect to the load as compared with other portions. The sensor attachment member 22 is made of a material having rigidity that is not deformed by an external force when the sensor unit 21 is attached to the knuckle 16.

  As the displacement sensor 23, in addition to the eddy current type, a magnetic type, an optical type, an ultrasonic type, a contact type or the like, or a sensor capable of detecting a displacement of any other type can be used. An appropriate sensor may be selected in accordance with various conditions.

  As shown in FIG. 1, acting force estimating means 31 and abnormality determining means 32 are provided as means for processing the output of the displacement sensor 23. These means 31 and 32 may be provided in an electronic circuit device (not shown) on a circuit board or the like attached to the outer member 1 of the wheel bearing, or may be an electric control unit of an automobile. (ECU) may be provided.

  The operation of the sensor-equipped wheel bearing with the above configuration will be described. When a load is applied to the hub wheel 9, the outer member 1 is deformed via the rolling elements 5, and the radial displacement of the outer member 1 due to the deformation is applied to the sensor attachment member 22 attached to the knuckle 16. Measurement is performed by the provided displacement sensor 23. At this time, since the outer peripheral surface of the outer member 1 to be measured by the displacement sensor 23 is a portion that is largely displaced in the radial direction as compared with the surroundings, the displacement of the outer member 1 can be measured with high sensitivity.

  Since the displacement varies depending on the direction and magnitude of the load, if the relationship between the displacement and the load is obtained in advance through experiments and simulations, the external force acting on the wheel bearing or the acting force between the tire and the road surface can be calculated. it can. From the relationship between the displacement and the load obtained and set in advance by experiments and simulations as described above, the acting force estimating means 31 is configured to output an external force acting on the wheel bearing or between the tire and the road surface by the output of the displacement sensor 23. Is calculated. The abnormality determining means 32 outputs an abnormal signal to the outside when it is determined that the external force acting on the wheel bearing calculated by the acting force estimating means 31 or the acting force between the tire and the road surface exceeds an allowable value. Output. This abnormal signal can be used for vehicle control of an automobile. Further, when an external force acting on the wheel bearing in real time or an acting force between the tire and the road surface is output, finer vehicle control becomes possible.

  In this embodiment, the sensor unit 21 is attached to only one upper portion of the knuckle 16. For example, as shown in FIG. 4, the sensor unit 21 is provided to two or more upper and lower portions of the knuckle 16. It is also good. If the sensor units 21 are provided at two or more locations, displacements at a plurality of locations on the outer peripheral surface of the outer member 1 can be measured, and therefore, a load with higher accuracy can be detected. In some cases, the sensor unit 21 may be attached to only one lower portion of the knuckle 16.

  FIG. 5 shows a different embodiment of the sensor unit. The sensor unit 21 is provided with a temperature sensor 24 in addition to the displacement sensor 23. The shape of the sensor mounting member 22 is the same as that shown in FIG. 3, and a temperature sensor 24 is mounted in the vicinity of the strain sensor 23 in the sensor mounting member 22. As the temperature sensor 24, for example, a platinum resistance thermometer, a thermocouple, or a thermistor can be used. Furthermore, a sensor capable of detecting a temperature other than these can also be used.

  Also in the wheel bearing provided with the sensor unit 21, the displacement sensor 23 detects the deformation of the outer member 1, and measures the load applied to the wheel by the deformation. Incidentally, the temperature of the wheel bearing and the knuckle 16 changes during use, and the change in temperature affects the deformation of the sensor mounting member 22 and the operation of the displacement sensor 23. It also has the same effect on changes in ambient environmental temperature. Therefore, the temperature sensor 24 arranged on the sensor mounting member 22 detects the temperature of the sensor mounting member 22 and corrects the output of the displacement sensor 23 based on the detected temperature, thereby removing the influence of the temperature of the displacement sensor 23. be able to. Thereby, it is possible to detect the load with high accuracy.

FIG. 6 shows yet another embodiment of the sensor unit. The sensor unit 21 is provided with various sensors 25 in addition to the displacement sensor 23. The various sensors 25 are at least one of an acceleration sensor and a vibration sensor. The shape of the sensor attachment member 22 is the same as that shown in FIG. 3, and various sensors 25 are attached in the vicinity of the displacement sensor 23.
Thus, when the displacement sensor 23 and the various sensors 25 are attached to the sensor attachment member 22, the load and the state of the wheel bearing can be measured at one place, and wiring and the like can be simplified.

  7 to 9 show further different embodiments. This wheel bearing incorporates a sensor signal processing circuit unit 60 for processing an output of a displacement sensor provided in the sensor unit 21 and each of the aforementioned sensors (temperature sensor, acceleration sensor, vibration sensor). The sensor signal processing circuit unit 60 is attached to the outer peripheral surface of the outer member 1.

  The sensor signal processing circuit unit 60 has a circuit board 62 made of glass epoxy or the like in a housing 61 made of resin or the like, and the output signal of the displacement sensor 23 is processed on the circuit board 62. An electric / electronic component 63 for power source for driving the operational amplifier, the resistor, the microcomputer, and the displacement sensor 23 is disposed. Further, a joint portion 64 that joins the wiring of the displacement sensor 23 and the circuit board 62 is provided. Further, it has a cable 65 for supplying power from the outside and outputting an output signal processed by the sensor signal processing circuit to the outside. When the sensor unit 21 is provided with each of the above-described sensors (temperature sensor, acceleration sensor, vibration sensor), the sensor signal processing circuit unit 60 includes a circuit board 62, an electric / electronic component 63, a joint corresponding to each sensor. A portion 64, a cable 65, and the like are provided.

  In general, a sensor signal processing circuit unit for processing the output of each sensor provided in a wheel bearing is provided in an electric control unit (ECU) of an automobile. As in this embodiment, a sensor in a wheel bearing is provided. By providing the sensor signal processing circuit unit 60 in the vicinity of the unit 21, labor for wiring from the sensor unit 21 to the sensor signal processing circuit unit 60 can be simplified, and the sensor signal processing circuit unit 60 is provided at a place other than the wheel bearing. The sensor signal processing circuit unit 60 can be installed more compactly than the case of providing the sensor.

  10 and 11 show an embodiment in which the mounting location of the sensor unit 21 is different from the above embodiments. In each of the above embodiments, the sensor unit 21 is attached to the upper part, the lower part, or both of the upper and lower parts of the knuckle 16, whereas in this embodiment, the sensor unit 21 is attached to the front part of the knuckle 16 in the vehicle traveling direction. Yes. As shown in FIG. 10, as means for processing the output of the displacement sensor 23, moment estimating means 33 is provided instead of the acting force estimating means 31 in the above embodiment. Other than this, the configuration is the same as that of the embodiment of FIGS. 1 to 3, and thus the same components are denoted by the same reference numerals and description thereof is omitted.

  Also in this embodiment, when a load is applied to the hub wheel 9, the outer member 1 is deformed via the rolling elements 5, and the radial displacement of the outer member 1 due to the deformation is attached to the knuckle 16. Measurement is performed by the displacement sensor 23 of the obtained sensor unit 21. At this time, since the outer peripheral surface of the outer member 1 to be measured by the displacement sensor 23 is a portion that is largely displaced in the radial direction as compared with the surroundings, the displacement of the outer member 1 can be measured with high sensitivity.

  In this embodiment, the steering moment acting on the wheel bearing can be calculated from the relationship between the displacement and the load. The steering moment is a moment applied to the wheel bearing when the vehicle travels on a curved path. The moment estimation means 33 calculates the steering moment acting on the wheel bearing based on the output of the displacement sensor 23 from the relationship between the displacement and the load obtained and set in advance through experiments and simulations. Based on this, the abnormality determination means 32 outputs an abnormality signal to the outside when it is determined that the steering moment acting on the wheel bearing exceeds the allowable value. This abnormal signal can be used for vehicle control of an automobile. Further, if the steering moment acting on the wheel bearing is output in real time, more detailed vehicle control becomes possible.

  In this embodiment, the sensor unit 21 is attached to only one front portion of the knuckle 16 in the vehicle traveling direction. However, as shown in FIG. It is good also as a structure attached to two or more places of the rear part. When the sensor unit 21 is attached to two or more places, it becomes possible to detect the steer moment with higher accuracy. In some cases, the sensor unit 21 may be attached to only one rear portion of the knuckle 16 in the vehicle traveling direction.

In each of the above embodiments, the case where the outer member 1 is a fixed side member has been described. However, the present invention can also be applied to a wheel bearing in which the inner member is a fixed side member. The displacement sensor 23 of the sensor unit 21 attached to the knuckle 16 measures the displacement of the inner peripheral surface of the inner member.
In each of the above embodiments, the case where the present invention is applied to a third generation type wheel bearing has been described. However, the present invention is applicable to a first or second generation type wheel in which the bearing portion and the hub are independent parts. The present invention can also be applied to a bearing or a fourth-generation type wheel bearing in which a part of the inner member is composed of an outer ring of a constant velocity joint. Further, this sensor-equipped wheel bearing can be applied to a wheel bearing for a driven wheel, and can also be applied to a tapered roller type wheel bearing of each generation type.

It is a figure showing combining the sectional view of the wheel bearing with a sensor concerning the embodiment of this invention, and the block diagram of the conceptual composition of the detection system. It is a front view which shows the outward member and sensor unit of the wheel bearing with a sensor. (A) is a side view of the sensor unit, and (B) is a bottom view thereof. It is a front view which shows the outward member and sensor unit of a different wheel bearing with a sensor. (A) is a side view of a different sensor unit, and (B) is a bottom view thereof. (A) is a side view of a further different sensor unit, and (B) is a bottom view thereof. It is sectional drawing of the bearing for wheels with a sensor concerning further different embodiment of this invention. It is a front view which shows the outward member, sensor unit, and sensor signal processing circuit unit of the wheel bearing with a sensor. It is a side view of the sensor signal processing circuit unit. It is a figure showing combining the sectional view of the bearing for wheels with a sensor concerning still another embodiment of this invention, and the block diagram of the conceptual composition of the detection system. It is a front view which shows the outward member and sensor unit of the wheel bearing with a sensor. Furthermore, it is a front view which shows the outward member and sensor unit of a different bearing for wheels with a sensor.

Explanation of symbols

1 ... Outer member (fixed side member)
2 ... Inward member (rotary member)
3, 4 ... rolling surface 5 ... rolling elements 7, 8 ... sealing device 16 ... knuckle 21 ... sensor unit 22 ... sensor mounting member 22a ... contact fixing part 23 ... displacement sensor 24 ... temperature sensor 25 ... various sensors 31 ... acting force Estimating means 32 ... Abnormality determining means 33 ... Moment estimating means 60 ... Sensor signal processing circuit unit 61 ... Housing 62 ... Circuit board 63 ... Electrical / electronic component 64 ... Joint 65 ... Cable

Claims (17)

An outer member in which a double row rolling surface is formed on the inner periphery, an inner member having a rolling surface opposite to the rolling surface of the outer member, and a double row interposed between both rolling surfaces A rolling bearing, and attached to a knuckle of a suspension device to rotatably support the wheel with respect to the vehicle body,
A sensor unit comprising a sensor mounting member and at least one displacement sensor mounted on the sensor mounting member is mounted on the knuckle, and the sensor mounting member has at least one contact fixing portion with respect to the knuckle. The wheel sensor-equipped bearing is characterized in that the displacement sensor measures a displacement of a surface of a fixed side member of the outer member and the inner member.   2. The wheel bearing with sensor according to claim 1, wherein the displacement sensor measures deformation of the fixed side member.   3. The displacement sensor according to claim 1, wherein the displacement sensor is compared with other portions of the fixed side member due to an external force applied to the fixed side member by an outer peripheral surface of the fixed side member or an applied force between the tire and the road surface. Sensor-equipped wheel bearings that measure the displacement at locations that are greatly deformed in the radial direction.   The sensor-equipped wheel bearing according to any one of claims 1 to 3, wherein the stationary member is an outer member.   5. The wheel bearing with sensor according to claim 1, wherein the sensor unit is attached to an upper portion, a lower portion, or both upper and lower portions of the knuckle.   6. The sensor-equipped wheel bearing according to claim 5, further comprising an acting force estimating means for estimating an external force acting on the wheel bearing or an acting force between the tire and the road surface based on the output of the displacement sensor.   5. The sensor-equipped wheel bearing according to claim 1, wherein the sensor unit is attached to a front part, a rear part, or both front and rear in the vehicle traveling direction of the knuckle.   8. The sensor-equipped wheel bearing according to claim 7, further comprising moment estimation means for estimating a steering moment acting on the wheel bearing based on an output of the displacement sensor.   9. The sensor-equipped wheel bearing according to claim 1, wherein the sensor unit includes a plurality of sensor units.   The sensor-equipped wheel bearing according to claim 1, wherein a temperature sensor is provided on the sensor mounting member.   11. The sensor-equipped wheel bearing according to claim 1, wherein the sensor mounting member is provided with at least one of an acceleration sensor and a vibration sensor.   12. The wheel bearing with sensor according to claim 1, wherein the displacement sensor is an eddy current sensor.   12. The wheel bearing with sensor according to claim 1, wherein the displacement sensor is a magnetic sensor.   The sensor-equipped wheel bearing according to claim 1, wherein the displacement sensor is an optical sensor.   The sensor-equipped wheel bearing according to claim 1, wherein the displacement sensor is a contact sensor.   The sensor-equipped wheel bearing according to any one of claims 1 to 11, wherein the displacement sensor is an ultrasonic sensor.   The sensor-equipped wheel bearing according to any one of claims 1 to 16, wherein a sensor signal processing circuit unit having a sensor signal processing circuit for processing an output signal of the displacement sensor is provided in the vicinity of the sensor unit.

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