JP2010242921A - Wheel bearing with sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wheel bearing with sensors, capable of highly accurately detecting a load acting on the wheel bearing and the ground contact surface of a tire by correcting a detection error due to the temperature difference between the inside and outside of the bearing and in which the sensors are easy to assemble. <P>SOLUTION: Rollers 5 are interposed between opposing double-row rolling faces 3, 4 of an outer member 1 and an inner member 2. Of the outer member 1 and the inner member 2, one or more sensor units 20 are provided to a fixed side member. The sensor units 20 includes: a strain generation member 21 fixed in contact with the outer diameter surface of the fixed side member; strain sensors 22, which detect the strain; sensor-part-temperature sensors 28, which detect the temperatures of the sensor installation parts; and rolling-face-temperature sensors 29, which detect the temperatures near the rolling face 3 of the fixed side member. An estimation means 30 is provided which corrects the output signals of the strain sensors 22 with the outputs of the sensor-part-temperature sensors 28 and the rolling-face-temperature sensors 29 and estimates a load that acts on the wheels from the corrected signal. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a sensor-equipped wheel bearing equipped with a load sensor that detects a load applied to a bearing portion of the wheel.

  As a technique for detecting a load applied to each wheel of an automobile, a sensor-equipped wheel bearing that detects a load by detecting a distortion of an outer diameter surface of a flange portion of an outer ring that is a fixed ring of a wheel bearing has been proposed ( For example, Patent Document 1). There has also been proposed a wheel bearing in which a strain gauge is attached to the outer ring of the wheel bearing to detect the strain (for example, Patent Document 2).

JP 2002-098138 A Special table 2003-530565 gazette

In the technique disclosed in Patent Document 1, distortion generated by deformation of the flange portion of the fixed ring is detected. However, the deformation of the flange portion of the fixed ring involves slipping when a force exceeding the static friction force is applied between the flange surface and the knuckle surface, so that hysteresis is generated in the output signal when a repeated load is applied. There is a problem.
For example, when the load in a certain direction with respect to the wheel bearing increases, the static friction force between the fixed ring flange surface and the knuckle surface does not slip at first, but exceeds a certain size. And it comes to slip over the static friction force. If the load is reduced in this state, it will not slip due to static friction force at first, but it will slip when it reaches a certain size. As a result, hysteresis occurs when an attempt is made to estimate the load at the portion where this deformation occurs. When hysteresis occurs, the detection resolution decreases.
In addition, when a strain gauge is attached to the outer ring as in Patent Document 2, there is a problem in assemblability.

  Therefore, the present inventors have proposed a sensor-equipped wheel bearing having the following configuration as a means for solving the above problems (for example, Japanese Patent Application No. 2008-314165). As shown in FIG. 19, the wheel bearing in this sensor-equipped wheel bearing includes an outer member 41 having a double-row rolling surface 43 formed on the inner periphery, and a rolling surface 44 that faces the rolling surface 43. Includes an inner member 42 formed on the outer periphery and a double row rolling element 45 interposed between the opposing rolling surfaces 43, 44 of both members 41, 42, and supports the wheel rotatably with respect to the vehicle body. To do. Among the outer member 41 and the inner member 42, a plurality of sensor units 50 are provided on the outer diameter surface of the outer member 41 serving as a fixed member as shown in FIG. As shown in FIGS. 21 and 22 in an enlarged plan view and an enlarged cross-sectional view, the sensor unit 50 has a strain generating member 51 having two contact fixing portions 51 a fixed in contact with the outer diameter surface of the outer member 41. And a strain sensor 52 which is attached to the strain generating member 51 and detects the strain of the strain generating member 51. A notch 51 b is formed between the two contact fixing portions 51 a of the strain generating member 51.

  In FIG. 22, the spacer 53 is interposed between the contact fixing portion 51 a of the strain generating member 51 and the outer member 41, thereby separating the mounting portion of the strain sensor 52 in the strain generating member 51 from the outer member 51. It is easy to generate distortion. In addition, as shown in FIG. 23, by providing a groove 41 c in a part of the outer diameter surface of the outer member 41, the strain sensor 52 mounting portion of the strain generating member 51 may be separated from the outer member 51. good.

  In this sensor-equipped wheel bearing, when a load is applied to the inner member 42 that is the rotation-side member as the vehicle travels, the outer member 41 that is the fixed-side member is deformed via the rolling elements 45, so that deformation Causes distortion in the sensor unit 50. The strain sensor 52 provided in the sensor unit 50 detects the strain of the sensor unit 50. By obtaining the relationship between strain and load in advance through experiments and simulations, the estimating means 60 can calculate and estimate the load applied to the wheel from the output signal of the strain sensor 52.

  With the above configuration, when the temperature changes, the output signal of the strain sensor 52 varies depending on the temperature characteristics of the strain sensor 52 and the difference in linear expansion coefficient between the outer member 41 and the sensor unit 50. For this reason, when the load applied to the wheel bearing is calculated and estimated from the output signal of the strain sensor 52, the error of the load becomes large. Therefore, here, a sensor section temperature sensor 58 that detects the temperature in the vicinity of the strain sensor 52 is attached to the strain generating member 51, and the output signal of the strain sensor 52 is corrected by the output of the sensor section temperature sensor 58.

  However, the internal temperature and the surface temperature of the outer member 41 of the wheel bearing differ depending on the heat generation inside the bearing (near the rolling surface) due to the load and changes in the contact conditions with the outside air (wind, moisture, temperature). There are many. In this state, the thermal strain due to the temperature gradient from the inside of the outer member 41 to the surface is superimposed on the output signal of the strain sensor 52. This thermal distortion cannot be reduced by the correction by the output of the sensor unit temperature sensor 58 described above, and the detection error increases.

  Therefore, the present inventors, in the sensor-equipped wheel bearing with the above-described configuration, are located near the rolling surface 43 in the circumferential position near the sensor unit 50 in the outer member 41 as shown in FIGS. A rolling surface temperature sensor 59 for detecting the temperature is provided, and the output signal of the strain sensor 52 of the sensor unit 50 is corrected by the outputs of the sensor temperature sensor 58 and the rolling surface temperature sensor 59, and the load is calculated from the corrected signal. It is also proposed to estimate. In this case, the detection error due to the temperature difference between the inside and outside of the bearing is corrected, so it is possible to reduce the influence of changes in the outside air temperature and fluctuations in the internal heat generation of the bearing due to load changes. Load can be detected with high accuracy and stability.

  However, in the configuration shown in FIGS. 24 and 25, the sensor unit 50 and the rolling contact surface temperature sensor 59 are not integrated. Therefore, it is necessary to separately assemble them on the outer member 41 of the bearing. To increase. Further, the process for assembling the rolling contact surface temperature sensor 59 inside the bearing is complicated. Furthermore, when sealing, wiring, and a cover are provided, it is necessary to separately perform operations on the sensor unit 50 and the rolling contact surface temperature sensor 59, which increases costs.

  An object of the present invention is to correct a detection error due to a temperature difference between the inside and outside of a bearing, detect a load acting on the wheel stably with high accuracy, and install a temperature sensor without increasing the number of mounting steps. It is to provide a bearing for an automobile.

  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 opposed to the rolling surface formed on the outer periphery, A wheel bearing comprising a double row rolling element interposed between opposing rolling surfaces of the member and rotatably supporting the wheel with respect to the vehicle body, wherein the fixed side member of the outer member and the inner member One or more sensor units are provided on the outer diameter surface of the strain generating member, and the sensor unit has two or more contact fixing portions fixed in contact with the outer diameter surface of the fixed-side member, and this strain generation A strain sensor attached to the member for detecting the strain of the strain generating member, a sensor temperature sensor attached to the strain generating member for detecting the temperature of the installation portion of the strain sensor, and the rolling in the fixed side member Rolling surface temperature sensor that detects the temperature near the surface Provided with an estimation means for correcting the output signal of the strain sensor of the sensor unit with the output of the sensor unit temperature sensor and the rolling surface temperature sensor, and estimating the load applied to the wheel from the corrected signal. It is characterized by. The stationary member may be an outward member, for example. The estimation of the load applied to the wheel in the estimation means may be performed by directly estimating the load applied to the wheel bearing, and the load applied to the wheel can be calculated from the load applied to the wheel bearing.

When a load acts between the wheel and the road surface, the load is also applied to a stationary member of the wheel bearing, for example, an outer member, and deformation occurs. Since the contact fixing part of the strain generating member in the sensor unit is fixed in contact with the fixed side member, the strain of the fixed side member is enlarged and transmitted to the strain generating member, and the strain is detected with high sensitivity by the sensor. It can be estimated with high accuracy.
In addition, in the estimation means for estimating the load, a sensor part temperature sensor that is attached to the strain generating member of the sensor unit and detects the temperature of the sensor installation part, and a rolling surface that detects the temperature in the vicinity of the rolling surface in the fixed member The output signal of the strain sensor of the sensor unit is corrected by the output of the temperature sensor, and the load applied to the wheels is estimated from the corrected signal. By correcting the detection error due to the temperature difference inside and outside the bearing, Thus, it becomes possible to reduce the influence of fluctuations in the internal heat of the bearing due to changes in the outside air temperature and load changes, and the load acting on the wheels can be detected stably with high accuracy.
In particular, since the rolling surface temperature sensor is also attached as a part of the sensor unit, the number of assembling steps to the fixed member can be reduced, and the work can be facilitated. Further, the wiring of the sensor part temperature sensor and the rolling surface temperature sensor can be combined on the strain generating member together with the wiring of the strain sensor, and the wiring process becomes easy. Furthermore, the rolling surface temperature sensor can be covered only by covering the sensor unit with a protective cover. As a result, the sensor can be easily assembled to the fixed member.

  In the present invention, three or more sensor units are provided, and the estimating means is configured to apply a radial load in the left-right direction and a vertical direction applied to the wheel from an output signal of a strain sensor of the three or more sensor units, and an axial load. It is good also as what estimates. In this specification, the left-right direction is the left-right direction when the wheel is viewed in the axial direction, and the radial load in the left-right direction is a load that becomes a driving force or a braking force.

  In this invention, four or more of the sensor units are provided, and the estimation means is configured to output a radial load in the horizontal direction and a vertical direction applied to the wheel, an axial load, The steering moment load may be estimated.

In the present invention, the four sensor units are provided, and these sensor units are arranged in an up-down position and a left-right position with respect to the tire ground contact surface of the wheel. , And the left surface portion may be arranged so as to form a phase difference of 90 degrees in the circumferential direction.
In this configuration, the load can be accurately estimated under any load condition. That is, when the load in a certain direction increases, the portion where the rolling element and the rolling surface are in contact with each other and the portion not in contact appear with a 180-degree phase difference. If installed, the load applied to the stationary member is always transmitted to one of the sensor units via the rolling elements, and the load can be detected by the sensor.

In this invention, the estimation means corrects the output signal of the strain sensor of the sensor unit based on the difference between the output of the sensor unit temperature sensor and the output of the rolling surface temperature sensor, and the correction amount by this correction is: It may be determined from a linear approximate relational expression between the set output difference between the two temperature sensors and the correction amount.
In the case of this configuration, the amount of offset superimposed on the sensor output signal of the sensor unit, that is, the thermal distortion due to the temperature gradient from the inside to the surface of the stationary member can be sufficiently reduced, and the accuracy of the load estimated value can be improved. .

  In this invention, the rolling surface temperature sensor in the sensor unit may be buried in a hole reaching the vicinity of the rolling surface provided in the fixed side member.

  Thus, when it is set as the structure which embeds a rolling surface temperature sensor in the inside of a hole, the rolling surface temperature sensor in the said sensor unit is attached to the front-end | tip of the temperature sensor attachment piece provided in the said distortion generation member, and this temperature The sensor mounting piece may be fixed by being press-fitted into a hole reaching the vicinity of the rolling surface provided in the fixed side member.

In the case where the rolling surface temperature sensor is embedded in the hole as described above, even if molding is performed with a mold material having high thermal conductivity between the rolling surface temperature sensor in the sensor unit and the inner surface of the hole. good. In the case of this configuration, the temperature in the vicinity of the rolling surface of the fixed member can be accurately detected by the rolling surface temperature sensor. The high thermal conductivity molding material is a mixture of ceramic powder such as alumina (AL ₂ O ₃ ), silica (SiO ₂ ), silicon carbide (SiC), etc. having high thermal conductivity, or carbon black as an additive. The term refers to a resin-based or rubber-based molding material with increased thermal conductivity, or a thermoplastic elastomer.

  In the present invention, a plate-shaped temperature sensor mounting piece is formed by bending a part of the strain generating member toward the radial direction of the fixed side member, and the rolling surface temperature sensor is disposed at the tip of the temperature sensor mounting piece. You may do it.

When the rolling surface temperature sensor is disposed on the plate-shaped temperature sensor mounting piece made of such a bent piece, a flat surface portion serving as a portion where the strain sensor is disposed in the strain generating member, and a rolling surface temperature sensor A wiring pattern may be formed on both of the temperature sensor mounting pieces to be arranged.
In this case, the wiring pattern of the plane portion where the strain sensor is arranged in the strain generating member and the wiring pattern of the temperature sensor mounting piece where the rolling surface temperature sensor is arranged are near the base end of the temperature sensor mounting piece. May be connected by a conductive wire.
By forming the wiring pattern in this way, the output of the rolling surface temperature sensor can be collected together with the output of the strain sensor and the sensor temperature sensor in one place on the strain generating member, and each sensor output signal can be extracted. Can be easily performed.

  In this invention, the estimation means may use an average value of output signals for several cycles of a signal that changes as the rolling element passes as an output signal of a strain sensor of the sensor unit used for load estimation. . For example, you may make it obtain | require the moving average which shifts the object of average value calculation for every period. The several cycles are 2-3 cycles or 5-6 cycles, and may be 2-6 cycles. By using an average value of a plurality of cycles, the output signal of the strain sensor can be obtained with high accuracy, and by performing the calculation within a range of several cycles, a quick calculation can be performed.

In this invention, the strain generating member in the sensor unit has three or more contact fixing portions fixed in contact with the outer diameter surface of the fixed side member, and the strain generating member includes at least two strain sensors. And the contact fixing part is arranged at an interval at which the phase difference between the output signals of the two strain sensors is 1/2 or an integer multiple of the arrangement pitch of the rolling elements. A sum of output signals of the two strain sensors corrected by outputs of the temperature sensor and the rolling surface temperature sensor may be obtained, and a load applied to the wheel may be estimated from the sum.
In the case of this configuration, the influence of the position of the rolling element is canceled out by the sum of the output signals of the two strain sensors, so that it is not affected by the rolling element and even when stopped, The load acting between the tire and the road surface can be detected with high accuracy.

  The sensor-equipped wheel bearing according to the present invention is the sensor-equipped wheel bearing according to any one of the above-described configurations of the present invention, wherein the strain generating member is in contact with and fixed to the outer diameter surface of the stationary-side member. Instead of a configuration in which a spacer is interposed between the fixed-side member and a rolling surface temperature sensor is attached to the strain generating member, a rolling surface temperature sensor may be attached to the spacer.

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 opposed to the rolling surface formed on the outer periphery, A wheel bearing comprising a double row rolling element interposed between opposing rolling surfaces of the member and rotatably supporting the wheel with respect to the vehicle body, wherein the fixed side member of the outer member and the inner member One or more sensor units are provided on the outer diameter surface of the strain generating member, and the sensor unit has two or more contact fixing portions fixed in contact with the outer diameter surface of the fixed-side member, and this strain generation A strain sensor attached to the member for detecting the strain of the strain generating member, a sensor temperature sensor attached to the strain generating member for detecting the temperature of the installation portion of the strain sensor, and the rolling in the fixed side member Rolling surface temperature sensor that detects the temperature near the surface Since the output signal of the strain sensor of the sensor unit is corrected with the output of the sensor unit temperature sensor and the rolling surface temperature sensor, and the estimation means for estimating the load applied to the wheel from the corrected signal is provided, The detection error due to the temperature difference between the inside and outside of the bearing is corrected, the load acting on the wheel can be detected stably with high accuracy, and the temperature sensor can be installed without increasing the number of mounting steps. Specifically, the following effects can be obtained.
The detection error of the strain sensor due to the temperature difference inside the fixed member of the bearing can be corrected, the influence of internal heat generation due to changes in the outside air temperature and load changes is reduced, and stable load detection with higher accuracy becomes possible.
Even if it is raining during driving or changes in outside air temperature, it is not easily affected, and even when driving under heavy load conditions, detection accuracy does not deteriorate and accurate vehicle control can be performed to increase safety. become.
Since each temperature sensor is integrated with the strain sensor, the temperature sensor can be installed without increasing the number of mounting steps.

It is a figure showing combining the sectional view of the wheel bearing with a sensor concerning one embodiment of this invention, and the block diagram of the conceptual composition of the detection system. It is the front view which looked at the outer member of the wheel bearing with a sensor from the outboard side. It is an expanded sectional view of the installation part of the rolling surface temperature sensor in the wheel bearing with the same sensor. It is an enlarged plan view of a sensor unit in the wheel bearing with sensor. It is a VV arrow sectional view in FIG. It is a graph which shows the relationship between the internal / external temperature difference of an outer member, and a distortion sensor output. It is an expanded sectional view of the installation part of the rolling surface temperature sensor in the wheel bearing with a sensor at the time of using the sensor unit of the other structural example. It is an enlarged plan view of the sensor unit. It is IX-IX arrow sectional drawing in FIG. It is an expanded sectional view of the sensor unit of other composition examples. It is a top view which expands and shows the sensor unit. It is a top view which expands and shows the sensor unit of other structural examples. It is a figure showing combining the sectional view of the wheel bearing with a sensor concerning other embodiments of this invention, and the block diagram of the conceptual composition of the detection system. It is the front view which looked at the outer member of the wheel bearing with a sensor from the outboard side. It is an enlarged plan view of a sensor unit in the wheel bearing with sensor. It is XVI-XV1 arrow sectional drawing in FIG. It is sectional drawing which shows the other example of installation of the sensor unit in the bearing for wheels with a sensor. It is explanatory drawing of the influence of a rolling-element position with respect to the output signal of the sensor unit. It is a figure which combines and shows the sectional view of the bearing for sensors with a wheel of a prior art example, and the block diagram of the conceptual structure of the detection system. It is the front view which looked at the outer member of the wheel bearing with a sensor from the outboard side. It is an enlarged plan view of a sensor unit in the wheel bearing with sensor. It is XXII-XXII arrow sectional drawing in FIG. It is sectional drawing which shows the other example of installation of the sensor unit in the bearing for wheels with a sensor. It is an expanded sectional view of the installation part of the rolling surface temperature sensor in the wheel bearing with the same sensor. It is an expanded sectional view which shows the other example of installation of the rolling surface temperature sensor in the wheel bearing with a sensor.

  A first 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.

  As shown in the sectional view of FIG. 1, the bearing for this sensor-equipped wheel bearing includes an outer member 1 in which a double row rolling surface 3 is formed on the inner periphery, and rolling facing each of these rolling surfaces 3. The inner member 2 has a surface 4 formed on the outer periphery, and the outer member 1 and the double row rolling elements 5 interposed between the rolling surfaces 3 and 4 of 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 have an arc shape in cross section, and are formed so that the ball contact angle is aligned with the back surface. Both ends of the bearing space between the outer member 1 and the inner member 2 are sealed by a pair of seals 7 and 8, respectively.

The outer member 1 is a fixed side member, and has a vehicle body mounting flange 1a attached to a knuckle 16 in a suspension device (not shown) of the vehicle body on the outer periphery, and the whole is an integral part. The flange 1a is provided with screw holes 14 for attaching a knuckle at a plurality of locations in the circumferential direction, and knuckle bolts (not shown) inserted into the bolt insertion holes 17 of the knuckle 16 from the inboard side are screwed into the screw holes 14. Thus, the vehicle body mounting flange 1a is attached to the knuckle 16.
The inner member 2 is a rotating 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 end portion on the inboard side of the shaft portion 9b of the hub wheel 9. And become. The hub wheel 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 (not shown) 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.

  FIG. 2 shows a front view of the outer member 1 of the wheel bearing as viewed from the outboard side. 1 shows a cross-sectional view taken along the line II in FIG. As shown in FIG. 2, the vehicle body mounting flange 1 a is a projecting piece 1 aa in which a circumferential portion provided with each screw hole 14 protrudes to the outer diameter side from the other portion.

  Four sensor units 20 are provided on the outer diameter surface of the outer member 1 which is a fixed member. Here, these sensor units 20 are arranged in the circumferential direction on the upper surface portion, the lower surface portion, the right surface portion, and the left surface portion of the outer diameter surface of the outer member 1 that is in the vertical position and the front and rear position with respect to the tire ground contact surface. Are provided so as to form a phase difference of 90 degrees.

  4 and 5, the sensor unit 20 includes a strain generating member 21 and a strain that is attached to the strain generating member 21 and detects the strain of the strain generating member 21. The sensor 22, the sensor part temperature sensor 28 that is attached to the strain generation member 21 and detects the temperature of the installation part of the strain sensor 22, and the rolling in the outer member 1 that is attached to the strain generation member 21 and is a fixed side member. It comprises a rolling surface temperature sensor 29 that detects the temperature in the vicinity of the running surface 3. The strain generating member 21 is made of a plate material such as an elastically deformable metal thin plate material such as a steel material, and the planar outline is a belt having a uniform width over the entire length, and has notches 21b on both sides of the center. Further, the strain generating member 21 has two contact fixing portions 21 a that are contact-fixed to the outer diameter surface of the outer member 1 via the spacers 23. Note that, depending on the shape of the strain generating member 21, it may have three or more contact fixing portions 21 a. The strain sensor 22 is affixed to a location where the strain increases with respect to the load in each direction on the strain generating member 21. Here, as the location, a central portion sandwiched between the notch portions 21b on both sides is selected on the outer surface side of the strain generating member 21, and the strain sensor 22 measures the circumferential strain around the notch portion 21b. To detect. Note that the strain generating member 21 is plastically deformed even in a state in which an assumed maximum force is applied as an external force acting on the outer member 1 that is a fixed member or an acting force acting between the tire and the road surface. It is desirable not to do so. This is because when plastic deformation occurs, the deformation of the outer member 1 is not transmitted to the sensor unit 20 and affects the measurement of strain. Even if an excessive load is applied to the bearing, the assumed maximum force is the maximum force within a range in which the normal function as the bearing excluding the sensor system is restored when the load is removed.

  In the sensor unit 20, the two contact fixing portions 21a of the strain generating member 21 are located at the same dimension in the axial direction of the outer member 1, and the two contact fixing portions 21a are separated from each other in the circumferential direction. These contact fixing portions 21a are fixed to the outer diameter surface of the outer member 1 by bolts 24 via spacers 23, respectively. Each bolt 24 is inserted into a bolt insertion hole 26 of the spacer 23 from a bolt insertion hole 25 penetrating in the radial direction provided in the contact fixing portion 21 a, and a screw hole 27 provided in the outer peripheral portion of the outer member 1. Screwed on. In this way, by fixing the contact fixing portion 21a to the outer diameter surface of the outer member 1 via the spacer 23, the central portion having the notch portion 21b in the strain generating member 21 having a thin plate shape is the outer member 1. It becomes a state away from the outer diameter surface of the, and distortion deformation around the notch 21b becomes easy. As the axial position where the contact fixing portion 21a is disposed, an axial position that is the periphery of the rolling surface 3 of the outboard side row of the outer member 1 is selected here. Here, the periphery of the rolling surface 3 of the outboard side row is a range from the intermediate position of the rolling surface 3 of the inboard side row and the outboard side row to the formation portion of the rolling surface 3 of the outboard side row. It is. In order to stably fix the sensor unit 20 to the outer diameter surface of the outer member 1, a flat portion 1 b is formed at a location where the spacer 23 is contacted and fixed on the outer diameter surface of the outer member 1.

Various strain sensors 22 can be used. For example, the strain sensor 22 can be composed of a metal foil strain gauge. In that case, the distortion generating member 21 is usually fixed by adhesion. The strain sensor 22 can also be formed on the strain generating member 21 with a thick film resistor.
For the sensor temperature sensor 28 and the rolling contact surface temperature sensor 29, for example, a semiconductor thermometer such as a thermistor, a thermocouple, a resistance temperature detector, or the like is used.

  Similar to the strain sensor 22, the sensor part temperature sensor 28 is attached to the surface of the strain generating member 21. As shown in FIG. 5, the strain generating member 21 has an L-shaped cross section in which one end is bent toward the radial direction of the outer member 1. A rolling surface temperature sensor 29 is installed on the tip surface of the temperature sensor mounting piece 21c formed of a bent piece forming one side of the L shape. Further, the outer member 1 is provided with a temperature sensor embedding hole 32 that extends in a radial direction from an installation portion of each sensor unit 20 on the outer diameter surface and reaches the vicinity of the rolling surface 3. The temperature sensor mounting piece 21c of the strain generating member 21 is embedded in the temperature sensor embedding hole 32, whereby the rolling surface temperature sensor is located at the bottom of the temperature sensor embedding hole 32 near the rolling surface 3. 29 is buried. Here, a rolling surface temperature sensor 29 is disposed at the tip of the temperature sensor mounting piece 21c, and the temperature sensor mounting piece 21c is press-fitted into the temperature sensor embedding hole 32. In the temperature sensor mounting piece 21c, a wiring hole 33 is formed which extends in the extending direction and opens on the surface of the strain generating member 21, and a signal connected to the rolling surface temperature sensor 29 through the wiring hole 33. The line 34 is drawn out to the surface of the distortion generating member 21. The bottom of the temperature sensor embedding hole 32 is preferably closer to the rolling surface 3 within a range in which the bearing life is not reduced by the formation of the hole 32. The vicinity of the boundary with the hardened portion. A protective cover 35 (FIG. 1) that covers each sensor unit 20 is provided on the outer periphery of the outer member 1 that is a stationary member.

  The strain sensor 22, the sensor part temperature sensor 28, and the rolling surface temperature sensor 29 of the sensor unit 20 are connected to the estimation means 30 in FIG. 1. The estimation means 30 is a force (vertical load Fz, load Fx serving as driving force or braking force, axial load Fy) acting on the wheel between the road surface (tire contact surface) and the output signal of the strain sensor 22. Temperature correction means 31 for correcting the output signal of the strain sensor 22 with the outputs of the sensor temperature sensor 28 and the rolling surface temperature sensor 29. In other words, the vertical load Fz and the load Fx serving as the driving force or the braking force are radial loads in the left-right direction and the up-down direction applied to the wheels, respectively. The left-right direction referred to in this specification is the left-right direction when the wheel is viewed in the axial direction as described above. The estimation unit 30 estimates the vertical load Fz, the load Fx serving as the driving force or the braking force, and the axial load Fy from the output signal of the strain sensor 22 corrected by the temperature correction unit 31. In addition to these loads, the estimating means 30 may estimate the steering moment load Mz.

  Since the output signal of the strain sensor 22 has a temperature drift characteristic, if the output signal of the strain sensor 2 is corrected by the temperature of the sensor unit 20 measured by the sensor temperature sensor 28 provided in the sensor unit 20 or the outside air temperature. Detection errors due to temperature drift characteristics can be reduced. However, if the amount of heat generated inside the bearing or the state of heat radiation to the outside air of the bearing changes, the thermal strain component of the outer member 1 is superimposed on the output signal of the strain sensor 22 to deteriorate the detection accuracy.

Therefore, the temperature correction means 31 in the estimation means 30 includes the temperature Ts of the installation part of the strain sensor 22 detected by the sensor part temperature sensor 28 and the internal temperature of the outer member 1 detected by the rolling contact surface temperature sensor 29. Based on the temperature Ti in the vicinity of the rolling surface 3, the output signal of the strain sensor 22 is corrected as follows.
First, ΔT = Ti−Ts is obtained as the temperature difference between the inside and outside of the outer member 1. The relationship between the temperature gradient inside and outside the outer member 1 and the offset amount superimposed on the output signal of the strain sensor 22 is determined by the structure of the outer member 1 and can be approximated by a proportional relationship as shown in the graph of FIG. A coefficient a indicating such a proportional relationship is obtained by a test or the like and set in the temperature correction means 31. In FIG. 6, the temperature of the sensor unit 20 is constant, and the output signal of the strain sensor 22 when the temperature difference ΔT = 0 is S0.
Next, the temperature correction means 31 uses the coefficient a indicating the proportional relationship of the graph of FIG. 6 and uses the internal / external temperature difference ΔT to obtain a correction value that is a value after correction of the output signal of the strain sensor 22.
Correction value = (output of strain sensor 22) + (offset O (Ts) due to sensor temperature)
+ (Offset G (ΔT) due to temperature gradient)
Asking. However,
O (Ts): offset amount due to difference in linear expansion + temperature characteristic of strain sensor 22
G (ΔT): offset amount due to temperature gradient,
It is.
Note that G (ΔT) = (coefficient a) × ΔT.

  The estimation means 30 includes a computer such as a microcomputer or an electronic circuit. The estimation unit 30 includes a relationship setting unit (not shown) in which the relationship between the acting force and the correction value of the output signal of the strain sensor 22 obtained by the temperature correction unit 31 is set by an arithmetic expression or a table. The value of the acting force is calculated and output from the input correction value using the relationship setting means. The setting contents of the relationship setting means are obtained by a test or simulation in advance.

  Since the sensor unit 20 is provided at an axial position around the rolling surface 3 of the outer board 1 on the outboard side row, the output signal of the strain sensor 22 passes in the vicinity of the installation portion of the sensor unit 20. It is affected by the rolling element 5. That is, when the rolling element 5 passes the position closest to the strain sensor 22 in the sensor unit 20, the amplitude of the output signal becomes the maximum value, and decreases as the rolling element 5 moves away from the position. Thereby, during rotation of the bearing, the output signal of the strain sensor 22 has a waveform close to a sine wave whose amplitude changes with the arrangement pitch of the rolling elements 5 as a period.

  Therefore, the calculation formula prepared for the load calculation by the estimation means 30 is, for example, the variable of the amplitude value of the temperature-corrected output signal of the strain sensor 22 of each sensor unit 20, and this variable is multiplied by a predetermined correction coefficient. Expressed as a linear expression. The correction coefficients and constants in this linear expression are calculation parameters. As another example of the arithmetic expression, a linear expression in which an average value (DC component) of the output signal of the strain sensor 22 of each sensor unit 20 is used as a variable and a predetermined correction coefficient is multiplied by this variable may be prepared. . As the average value in this case, the average value of the output signal for several cycles of the signal amplitude that changes as the rolling element 5 passes is used. For example, you may make it obtain | require the moving average which shifts the object of average value calculation for every period. The several cycles are 2-3 cycles or 5-6 cycles, and may be 2-6 cycles. As yet another example of the arithmetic expression, an average value and an amplitude value of the output signal of the strain sensor 22 of each sensor unit 20 are used as variables, and a linear expression obtained by multiplying these variables by a predetermined correction coefficient is set. Also good. The values of the correction coefficients and constants in the linear equation are determined and set in advance through tests and simulations.

When a load acts between the tire of the wheel and the road surface, the load is also applied to the outer member 1 that is a stationary member of the wheel bearing, causing deformation. Since the two contact fixing portions 21a of the strain generating member 21 in the sensor unit 20 are fixed in contact with the outer member 1, the strain of the outer member 1 is transmitted to the strain generating member 21 in an enlarged manner, and the strain is distorted. It is detected with high sensitivity by the sensor 22 and the load can be estimated with high accuracy.
Further, a sensor part temperature sensor 28 for detecting the temperature of the installation part of the strain sensor 22 on the strain generating member 21 of the sensor unit 20, and a rolling surface temperature sensor for detecting the temperature in the vicinity of the rolling surface 3 in the outer member 1. 29, and in the estimation means 30, the temperature correction means 31 corrects the output signal of the strain sensor 22 with the outputs of the sensor part temperature sensor 28 and the rolling surface temperature sensor 29, and the wheel bearing or Since the load applied to the tire is estimated, it becomes possible to reduce the influence of changes in the outside air temperature and fluctuations in the internal heat generation of the bearing due to the load change, and the load acting on the wheel bearing and tire contact surface is high. It can be detected accurately and stably, and even when there is rainfall or a change in the outside air temperature, it is less affected by load detection.
In particular, since the rolling surface temperature sensor 29 is also attached to the strain generating member 21 as a part of the sensor unit 20, the number of assembling steps to the outer member 1 can be reduced, and the work is facilitated. Moreover, since the wiring of the sensor part temperature sensor 28 and the rolling surface temperature sensor 29 can be collected on the strain generating member 21 together with the wiring of the strain sensor 22, wiring processing is facilitated. Furthermore, the rolling surface temperature sensor 29 can be covered only by covering the sensor unit 20 with the protective cover 35.

Although the case where the acting force between the wheel tire and the road surface is detected has been described in the above description, not only the acting force between the wheel tire and the road surface but also the force acting on the wheel bearing (for example, the preload amount) is detected. It is good as a thing.
By using the detection load obtained from this sensor-equipped wheel bearing for vehicle control, the detection accuracy will not deteriorate even when traveling under conditions with high load, and safety will be improved by accurate vehicle control. Can do.

  Further, in this embodiment, four sensor units 20 are provided, and these sensor units 20 are arranged on the upper surface portion, the lower surface portion, and the outer diameter surface of the outer member 1 that are in the vertical position and the horizontal position with respect to the tire ground contact surface. Since the right surface portion and the left surface portion are arranged so as to have a phase difference of 90 degrees in the circumferential direction, the load can be accurately estimated under any load condition. That is, when a load in a certain direction increases, a portion where the rolling element 5 and the rolling surfaces 3 and 4 are in contact with each other and a portion which is not in contact appear with a phase difference of 180 degrees. Is installed with a phase difference of 180 degrees, a load applied to the outer member 1 is always transmitted to one of the sensor units 20 via the rolling elements 5, and the load can be detected by the strain sensor 22.

  In this embodiment, the temperature correction means 31 of the estimation means 30 causes the output signal of the strain sensor 22 of the sensor unit 20 based on the difference between the output of the sensor unit temperature sensor 28 and the output of the rolling surface temperature sensor 29. The correction amount is determined from the first-order approximate relational expression (FIG. 6) between the output difference between the temperature sensors 28 and 29 and the correction amount prepared in advance. The amount of offset superimposed on the outer member 1, that is, the thermal distortion due to the temperature gradient from the inside to the surface of the outer member 1, can be sufficiently reduced, and the accuracy of the estimated load value can be improved.

  7 and 8 show another configuration example of the sensor unit 20 in the embodiment. In this configuration example, the temperature sensor is formed of a bent piece that is bent inward in the radial direction of the outer member 1 at a portion facing the axial direction of the outer member 1 at one end portion fixed by the bolt 24 of the strain generating member 21. A mounting piece 21d is provided, and a rolling contact surface temperature sensor 29 is arranged at the tip of the temperature sensor mounting piece 21d. The temperature sensor mounting piece 21d is press-fitted into the temperature sensor embedding hole 32 that extends in the radial direction from the installation portion of the sensor unit 20 on the outer diameter surface of the outer member 1 and reaches the vicinity of the rolling surface 3. The rolling surface temperature sensor 29 is embedded at the bottom near the rolling surface 3 in the temperature sensor embedding hole 32. Other configurations are the same as those of the configuration examples shown in FIGS.

  FIG. 9 shows still another configuration example of the sensor unit 20 in the embodiment. In this configuration example, from one of the spacers 23 interposed between the contact fixing portion 21 a of the strain generating member 21 and the outer diameter surface of the outer member 1, a protrusion extending in the radial direction of the outer member 1. A temperature sensor mounting piece 23a is provided, and a rolling surface temperature sensor 29 is disposed on the tip surface of the temperature sensor mounting piece 23a. The temperature sensor mounting piece 23 a is press-fitted into the temperature sensor embedding hole 32 extending in the radial direction from the installation portion of the sensor unit 20 on the outer diameter surface of the outer member 1 and reaching the vicinity of the rolling surface 3. The rolling surface temperature sensor 29 is embedded at the bottom near the rolling surface 3 in the temperature sensor embedding hole 32. In the temperature sensor mounting piece 23a, a wiring hole 33A extending in the extending direction and opening on the surface is formed, and the strain generating member 21 is penetrated in the thickness direction and aligned with the wiring hole 33A. 33B is formed. As a result, a signal line (not shown) connected to the rolling surface temperature sensor 29 is drawn out to the surface of the strain generating member 21 through the wiring holes 33A and 33B. Other configurations are the same as the configuration examples shown in FIGS. 4 and 5.

10 and 11 show still another configuration example of the sensor unit 20 in the embodiment. In this configuration example, a temperature sensor mounting piece 21c made of a bent piece bent toward the radially inner side of the outer member 1 is provided at one end of the strain generating member 21 fixed by the bolt 24, and the temperature sensor mounting piece 21c. A rolling contact surface temperature sensor 29 is disposed at the tip of the flat surface portion that is the front surface. In addition, in FIG. 11, it has shown as the expanded view before bending the said temperature sensor attachment piece 21c. The temperature sensor mounting piece 21c is embedded in a temperature sensor embedding hole 32 that extends in the radial direction from the installation portion of the sensor unit 20 on the outer diameter surface of the outer member 1 and reaches the vicinity of the rolling surface 3. Here, the installation part of the rolling contact surface temperature sensor 29 embedded in the temperature sensor embedding hole 32, that is, the temperature sensor mounting piece 21c is molded with the molding material 36 having high thermal conductivity. The high thermal conductivity molding material 36 referred to here is ceramic powder such as alumina (AL ₂ O ₃ ), silica (SiO ₂ ), silicon carbide (SiC), etc. having high thermal conductivity, or carbon black as an additive. By mixing, it is a resin-based or rubber-based molding material whose thermal conductivity is increased, or a thermoplastic elastomer.

  When the strain generating member 21 is a thin plate that is thinner than a certain degree, the wiring hole 33 cannot be provided in the temperature sensor mounting piece 21c as in the configuration example of FIG. Therefore, in this configuration example, the rolling contact surface temperature sensor 29 is arranged on the tip flat portion of the temperature sensor attachment piece 21c as shown in FIG. 10, so that the signal line connected to the rolling contact surface temperature sensor 29 is connected to the temperature sensor attachment. It pulls out through the surface of the piece 21c. Further, since the temperature sensor mounting piece 21c is molded with the molding material 36 having good thermal conductivity, the temperature in the vicinity of the rolling surface 3 of the outer member 1 can be accurately detected by the rolling surface temperature sensor 29. it can. Further, since the temperature sensor embedding hole 32 is sealed with the molding material 36, wiring processing is facilitated, and moisture can be prevented from entering the outer member 1 through the temperature sensor embedding hole 32. .

  FIG. 12 shows still another configuration example of the sensor unit 20 in the embodiment. In this configuration example, a temperature sensor mounting piece 21c bent toward the radial direction of the outer member 1 is provided at one end of the strain generating member 21 fixed by the bolt 24, and the tip end flat portion of the temperature sensor mounting piece 21c is provided. A rolling surface temperature sensor 29 is disposed. In the drawing, the temperature sensor mounting piece 21c is shown as a development before being bent, and the sensor temperature sensor 28 is not shown. A wiring pattern 37A connected to the rolling surface temperature sensor 29 is formed on the flat surface portion of the temperature sensor mounting piece 21c where the rolling surface temperature sensor 29 is disposed, and the strain sensor 22 and the sensor portion temperature sensor 28 are disposed. Wiring patterns 37B, 37C, and 37D are also formed on the planar portion. Then, in the vicinity of the boundary between both plane portions, the electrode 37Aa of the wiring pattern 37A in the plane portion where the rolling contact surface temperature sensor 29 is arranged, and the electrodes 37Ba of the wiring patterns 37B and 37C in the plane portion where the strain sensor 22 is arranged. 37Ca is connected by the conducting wire 38. Moreover, you may print-mold the conductor 38 part similarly to another part. Each wiring pattern 37B, 37C, 37D on the plane portion where the strain sensor 22 is arranged and the sensor portion temperature sensor 28 (not shown) are connected to another cable 39. The output signals of the strain sensor 22, the sensor part temperature sensor 28, and the rolling contact surface temperature sensor 29 are taken out through the cable 39.

  In this manner, the wiring pattern wiring patterns 37A, 37B, 37C, and 37D are formed on both the plane portion where the strain sensor 22 is arranged and the plane portion where the rolling contact surface temperature sensor 29 is arranged, and the strain sensor 22 By connecting the wiring patterns 37B and 37C of the flat part to be arranged and the wiring pattern 37A of the flat part where the rolling contact surface temperature sensor 29 is arranged by a conductor 38 in the vicinity of the boundary between the two flat parts, rolling The output of the surface temperature sensor 29 can be collected together with the outputs of the strain sensor 22 and the sensor temperature sensor 28 at one place on the strain generating member 21, and the output signals of the sensors can be easily taken out.

  13 to 18 show another embodiment of the present invention. 13 shows a cross-sectional view taken along arrow XIII-XIII in FIG. In this embodiment, in the embodiment shown in FIGS. 1 to 11, the sensor unit 20 includes a strain generating member 21 and the strain generating member 21 as shown in FIGS. 15 and 16 in an enlarged plan view and an enlarged sectional view. And two or more (two in this case) strain sensors 22 that detect the strain of the strain generating member 21, a sensor section temperature sensor 28, and a rolling surface temperature sensor 29. The strain generating member 21 has two or more (here, three) contact fixing portions 21 a that are fixed to the outer diameter surface of the outer member 1 through spacers 23. The three contact fixing portions 21 a are arranged in a line in the longitudinal direction of the strain generating member 21. The two strain sensors 22 are arranged between the contact fixing portions 21 a adjacent on the outer surface side of the strain generating member 21. One strain sensor 22A is disposed between the contact fixing portion 21a at the left end and the contact fixing portion 21a at the center, and another strain sensor 22B is provided between the contact fixing portion 21a at the center and the contact fixing portion 21a at the right end. Is placed. The sensor part temperature sensor 28 is attached to the surface of the strain generating member 21, and the temperature sensor attaching piece 21c extending in the radial direction of the outer member 1 is formed at one end of the strain generating member 21, and the tip of the temperature sensor attaching piece 21c is formed. The rolling surface temperature sensor 29 is disposed at the site, and the temperature sensor mounting piece 21c is embedded in the temperature sensor embedding hole 32 of the outer member 1 in the case of the embodiment shown in FIGS. It is the same.

  As shown in the cross-sectional view of FIG. 17, the sensor unit 20 is installed at three locations where the three contact fixing portions 21 a of the strain generating member 21 on the outer diameter surface of the outer member 1 are fixed. By providing the groove 1c in each intermediate portion, the spacer 23 may be omitted, and each portion where the notch portion 21b in the strain generating member 21 is located may be separated from the outer diameter surface of the outer member 1.

  The two strain sensors 22 of each sensor unit 20 are connected to the estimation means 30. In the embodiment shown in FIGS. 1 to 11, the estimation means 30 corrects the temperatures of the output signals of the two strain sensors 22 based on the output signals of the sensor section temperature sensor 28 and the rolling surface temperature sensor 29. It is the same. In the case of this embodiment, the estimating means 30 obtains the sum of the temperature-corrected output signals of the two strain sensors 22 of the sensor unit 20, and acts on the wheel bearing or between the wheel and the road surface (tire contact surface) from this sum. To be estimated (vertical load Fz, driving force or braking force Fx, axial load Fy) and steering moment load Mz.

  As described in the previous embodiment, the sensor unit 20 is provided at the axial position around the rolling surface 3 of the outboard side row of the outer member 1, and therefore the output signal A of the strain sensors 22 </ b> A and 22 </ b> B. , B are affected by the rolling element 5 passing near the installation part of the sensor unit 20 as shown in FIG. Even when the bearing is stopped, the output signals A and B of the strain sensors 22A and 22B are affected by the position of the rolling element 5. That is, when the rolling element 5 passes through the position closest to the strain sensors 22A and 22B in the sensor unit 20, or when the rolling element 5 is at that position, the output signals A and B of the strain sensors 22A and 22B are maximum values. As shown in FIGS. 18A and 18B, the rolling element 5 decreases as the distance from the position increases. Since the rolling elements 5 sequentially pass through the vicinity of the installation portion of the sensor unit 20 at a predetermined arrangement pitch P when the bearing rotates, the output signals A and B of the strain sensors 22A and 22B indicate the arrangement pitch P of the rolling elements 5. As a cycle, as shown by a solid line in FIG. 18C, the waveform is close to a sine wave that periodically changes.

  In the case of this embodiment, the estimating means 30 uses the sum of the output signals A and B of the two strain sensors 22A and 22B to determine the force that the estimating means 30 acts between the wheel bearings and the wheels and the road surface (tire contact surface) ( Estimate the vertical load Fz, the driving force or braking force Fx, the axial load Fy) and the steering moment load Mz. In this case, the sum of the output signals A and B of the two strain sensors 22A and 22B corresponds to the average value (DC component) of the output signals of the one strain sensor 22 in the previous embodiment. Thereby, it is possible to cancel the influence of the position of the rolling element 5 appearing in the output signals A and B of the two strain sensors 22A and 22B, and to accurately detect the load acting on the wheel bearing and the tire ground contact surface. Can do.

  In FIG. 18 showing the installation example of FIG. 17 as the sensor unit 20, among the three contact fixing portions 21a arranged in the circumferential direction of the outer diameter surface of the outer member 1 which is a fixed side member, The interval between the two contact fixing portions 21 a located at both ends is set to be the same as the arrangement pitch P of the rolling elements 5. In this case, the circumferential interval between the two strain sensors 22A and 22B respectively disposed at the intermediate positions of the adjacent contact fixing portions 21a is approximately ½ of the arrangement pitch P of the rolling elements 5. As a result, the output signals A and B of the two strain sensors 22A and 22B have a phase difference of about 180 degrees, and the average value (A + B) / 2 is as indicated by a chain line in FIG. This is a value that sufficiently offsets the influence of the position of the rolling element 5. As a result, the force (vertical load Fz, F), acting on the wheel bearings or between the wheel and the road surface (tire contact surface) estimated by the estimating means 30 from the sum of the output signals A and B of the two strain sensors 22A and 22B. The driving force or braking force Fx, axial load Fy) and steering moment load Mz are accurate with the influence of the position of the rolling element 5 removed more reliably.

  Instead of setting the interval between the three contact fixing portions 21a of the strain generating member 21 as described above, the interval between the two strain sensors 22A and 22B in the circumferential direction is equal to the arrangement pitch P of the rolling elements 5. It may be an integer multiple of 1/2 or a value approximate to these values. Also in this case, the average value (A + B) / 2 of the output signals A and B of both strain sensors 22A and 22B is a value that cancels out the influence of the position of the rolling element 5.

DESCRIPTION OF SYMBOLS 1 ... Outer member 2 ... Inner member 3, 4 ... Rolling surface 5 ... Rolling body 20 ... Sensor unit 21 ... Strain generating member 21a ... Contact fixing | fixed part 21c ... Temperature sensor attachment piece 22 ... Strain sensor 23 ... Spacer 23a ... Temperature sensor mounting piece 28 ... sensor temperature sensor 29 ... rolling surface temperature sensor 30 ... estimating means 31 ... temperature correcting means 32 ... temperature sensor embedding hole 36 ... mold material 37A, 37B, 37C ... wiring pattern 38 ... conductor

Claims (15)

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 formed on the outer periphery, and interposed between the opposing rolling surfaces of both members A double row rolling element, and a wheel bearing for rotatably supporting the wheel with respect to the vehicle body,
One or more sensor units are provided on the outer diameter surface of the fixed side member of the outer member and the inner member, and the sensor unit is fixed in contact with the outer diameter surface of the fixed side member. A strain generating member having the above-described contact fixing portion, a strain sensor attached to the strain generating member to detect strain of the strain generating member, and a temperature of an installation portion of the strain sensor attached to the strain generating member. A sensor part temperature sensor, and a rolling surface temperature sensor for detecting a temperature in the vicinity of the rolling surface of the stationary member, and output signals of the strain sensor of the sensor unit are output to the sensor part temperature sensor and the rolling surface temperature. A sensor-equipped wheel bearing, comprising: an estimation means for correcting a load applied to a wheel from the corrected signal by correcting with an output of the sensor.   The sensor-equipped wheel bearing according to claim 1, wherein the fixed-side member is the outer member.   3. The three or more sensor units are provided according to claim 1, and the estimation unit is configured to apply a radial load in a lateral direction and a vertical direction applied to a wheel from an output signal of a strain sensor of the three or more sensor units. And a bearing for a wheel with a sensor for estimating an axial load.   4. The sensor unit according to claim 1, wherein four or more of the sensor units are provided, and the estimation unit is configured to apply a radial load in a horizontal direction and a vertical direction applied to a wheel from an output signal of a strain sensor of the four or more sensor units. A wheel bearing with sensor that estimates the axial load and steering moment load.   5. The outer diameter of the fixed-side member according to claim 1, wherein four sensor units are provided, and the sensor units are arranged in a vertical position and a horizontal position with respect to a tire ground contact surface of a wheel. A sensor-equipped wheel bearing disposed on an upper surface portion, a lower surface portion, a right surface portion, and a left surface portion of the surface so as to form a phase difference of 90 degrees in the circumferential direction.   6. The method according to claim 1, wherein the estimating means outputs an output signal of a strain sensor of the sensor unit based on a difference between an output of the sensor unit temperature sensor and an output of the rolling surface temperature sensor. A sensor-equipped wheel bearing in which correction is performed and a correction amount by the correction is determined from a linear approximate relational expression between the set output difference between the two temperature sensors and the correction amount.   7. The wheel bearing with sensor according to claim 1, wherein the rolling surface temperature sensor in the sensor unit is buried in a hole reaching the vicinity of the rolling surface provided in the fixed side member.   In Claim 7, The rolling surface temperature sensor in the said sensor unit is attached to the front-end | tip of the temperature sensor attachment piece provided in the said distortion generation member, and this temperature sensor attachment piece is provided in the said fixed side member. Sensor-equipped wheel bearing fixed by press-fitting into a hole that reaches the vicinity.   The wheel bearing with sensor according to claim 7, wherein the sensor unit is molded with a mold material having high thermal conductivity between a rolling surface temperature sensor and an inner surface of the hole.   The plate-shaped temperature sensor mounting piece obtained by bending a part of the distortion generating member toward the radial direction of the fixed side member according to any one of claims 1 to 9, A sensor-equipped wheel bearing in which the rolling surface temperature sensor is arranged at the tip.   11. The sensor-equipped wheel bearing according to claim 10, wherein a wiring pattern is formed on both of a flat surface portion where the strain sensor is disposed in the strain generating member and a temperature sensor mounting piece where the rolling surface temperature sensor is disposed. .   In Claim 11, the wiring pattern of the plane part by which the strain sensor in the said strain generation member is arrange | positioned, and the wiring pattern of the temperature sensor attachment piece by which a rolling surface temperature sensor is arrange | positioned are the base ends of the said temperature sensor attachment piece. Sensor-equipped wheel bearing connected by a conducting wire in the vicinity.   13. The method according to claim 1, wherein the estimating means outputs, as an output signal of a strain sensor of the sensor unit used for load estimation, a signal corresponding to several cycles of a signal that changes as the rolling element passes. Wheel bearing with sensor that uses the average value of the signal.   13. The strain generating member in the sensor unit according to claim 1, wherein the strain generating member includes three or more contact fixing portions that are fixed in contact with an outer diameter surface of the fixing side member. At least two strain sensors are attached to the strain generating member, and the contact fixing portions are arranged at intervals at which the phase difference between the output signals of the two strain sensors is 1/2 or an integer multiple of the arrangement pitch of the rolling elements. The estimation means obtains a sum of output signals of the two strain sensors corrected by outputs of the sensor temperature sensor and the rolling surface temperature sensor, and estimates a load applied to the wheel from the sum. Wheel bearing. 15. The spacer according to claim 1, wherein a spacer is interposed between the fixed member and the contact fixing part that is fixed in contact with the outer diameter surface of the fixed member in the strain generating member. In addition, instead of a configuration in which a rolling surface temperature sensor is attached to the strain generating member, a wheel bearing with sensor in which a rolling surface temperature sensor is attached to the spacer.

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