JP2012255544A - Sensor-equipped wheel bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sensor-equipped wheel bearing enabling improvement in quality of a wiring part, and cost reduction, without requiring complicated wiring work.SOLUTION: A wheel bearing has a rolling element 5 interposed between mutually opposing double rows of rolling surfaces of an outer member 1 and an inner member 2. A plurality of load detecting sensor units 20 each composed of a strain-generating member 21 and a sensor 22 installed in the strain-generating member and detecting its strain, is provided. The strain generating member 21 is a single strip-shaped member continuous across the plurality of load detecting sensor units 20, and a contact-fixed part 21a assigned to each of the load detecting sensor units 20, is arranged in a fixed side member out of the outer member 1 and the inner member 2. A load acting on the wheel bearing is estimated by an estimation means from output signals of the two or more of sensors 22 of the load detecting sensor units 20. The load detecting sensor units 20 are covered with a cover together with the fixed side member. A lip part is provided on one end of the cover.

Description

  The present invention relates to a sensor-equipped wheel bearing provided 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, an electronic component composite shown in a development view in FIG. 36 is arranged inside an annular protective cover to form an annular sensor assembly. A sensor-equipped wheel bearing has been proposed that is mounted concentrically with the fixed side member on the peripheral surface of the fixed side member of the outer and inner members of the wheel bearing via a seal member (for example, Patent Document 1). . The electronic component composite shown in FIG. 1 is a strain generating member 51 fixed in contact with the peripheral surface of the fixed side member, and a sensor 52 that is attached to the strain generating member 51 and detects the strain of the strain generating member 51. 4, a signal processing IC 55 for processing the output signal of the sensor 52, and a signal cable 56 for taking out the processed output signal to the outside of the bearing.

  As another technique, as shown in development and cross-sectional views in FIGS. 37A and 37B, in the electronic component composite shown in FIG. 36, the sensor unit 50, the signal processing IC 55, and A sensor-equipped wheel bearing having a configuration in which a flexible substrate 65 having a wiring circuit for wiring between the signal cables 56 is added has also been proposed (for example, Patent Document 2).

JP 2010-138958 A JP 2010-127750 A

  In the sensor-equipped wheel bearing disclosed in Patent Document 1, four strain generating members 51 are wired via a signal cable 56 by soldering or the like to constitute the electronic component composite. For this reason, the wiring work of the signal cable 56 is a complicated and expensive factor.

  On the other hand, even with the sensor-equipped wheel bearing disclosed in Patent Document 2, the work of connecting the four strain generating members 51 and the flexible substrate 65 by soldering or the like is required to form the electronic component composite. In addition, when the wiring part is fixed with solder, it is conceivable that a crack is generated in the solder part due to vibration or the like during traveling of the vehicle, and the sensor 52 does not normally detect and operate.

  Furthermore, in the sensor-equipped wheel bearing disclosed in Patent Document 2, in order to prevent the sensor 52 from being corroded by muddy water or the like in the external environment, the electronic device is disposed inside the annular protective cover 57 as shown in FIG. A component composite is arranged, and a molding material 58 is filled in the outer diameter side groove of the protective cover 57. However, as shown in FIG. 39, the protective cover 57 has a half-cracked shape via the hinge 60, and thus has a problem from the viewpoint of sealing performance, assembling performance, and cost. In addition, since the entire protective cover 57 is not covered with metal, it may be damaged if it collides with a pebble or the like that has jumped while the vehicle is running, and the internal sensor 52 may not be normally detected.

  The object of the present invention is that no complicated wiring work is required, the quality of the wiring part can be improved and the cost can be reduced, the sensor can be protected from the collision of pebbles and the like jumped during traveling, and muddy water from the outside It is possible to provide a sensor-equipped wheel bearing that can prevent intrusion into a sensor and the like and can stably sense for a long period of time.

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 Further, a strain generating member having two or more contact fixing portions fixed in contact with the fixed side member, and two or more sensors attached to the strain generating member and detecting the strain of the strain generating member A sensor-equipped wheel bearing provided with a plurality of load detection sensor units, wherein an estimation means for estimating a load acting on the wheel bearing is provided based on output signals of the two or more sensors.
The strain generating members of the plurality of load detecting sensor portions are used as one belt-like strain generating member continuous over the plurality of load detecting sensor portions, and the two or more contact fixings in the belt-shaped strain generating members are performed. The parts are arranged so as to be at the same axial position on the outer diameter surface of the fixed side member and at positions separated from each other in the circumferential direction,
A plurality of load detection sensors are covered with a cylindrical protective cover that surrounds the outer periphery of the fixed member, and is fitted to the outer periphery of the fixed member at one end in the axial direction of the protective cover. An annular seal member made of an elastic body is provided on the surface, and the seal member is brought into contact with the surface of the stationary member or the surface of the rotating member of the outer member and the inner member.
The stationary member may be an outer member, and the rotating member may be the inner member. The seal member may be, for example, a lip portion or an O-ring.

  When a load acts between the wheel bearing or the wheel tire and the road surface, the load is also applied to the stationary side member (for example, the outer member) of the wheel bearing to cause deformation. Detect load. The output signals of two or more sensors in the load detection sensor section are affected by the passage of rolling elements, but the estimation means determines the bearings for wheels and the distance between the wheels and the road surface (tire contact surface) from the output signals of these sensors. Force (vertical load Fz, driving force or braking force Fx, axial load Fy) is estimated, so the temperature effect on each output signal of two or more sensors and knuckle The effect of slippage between the flange surfaces can be offset or reduced. As a result, the load (vertical load Fz, driving force and braking force) acting between the wheel bearing and the tire of the wheel and the road surface without being affected by the temperature or the slippage between the knuckle and the flange surface. The load Fx and the axial load Fy) can be detected with high accuracy.

In particular, since the strain generating members of the plurality of load detecting sensor portions are one band-like strain generating member continuous across the plurality of load detecting sensor portions, no complicated wiring work is required. Quality improvement and cost reduction are possible.
In addition, since the sensor assembly having a plurality of load detection sensor portions is covered with a protective cover, the plurality of load detection sensor portions are protected from the external environment by, for example, protecting the sensor from a collision of pebbles or the like jumped while the vehicle is running. Can be protected from. For this reason, it is possible to stably detect the load acting on the wheel bearing and the tire ground contact surface for a long period of time by preventing a failure of the load detection sensor unit due to the external environment.
Furthermore, since a sealing member is added to the protective cover to add a sealing function, muddy water from the outside can be prevented from entering the sensor, and sensing can be performed stably for a longer period of time.

In the present invention, the one belt-like strain generating member may be bent at a plurality of locations in the longitudinal direction and fixed to the stationary member.
In this way, by bending one belt-like strain generating member having a plurality of load detection sensor portions at a plurality of locations, the attachment work to the fixed member is facilitated.

In this invention, the fixed side member has a flange for attachment to the vehicle body on the outer periphery, and the shape of the fixed side member viewed from the front side in the bearing axial direction is relative to a line segment orthogonal to the bearing axis. It may be a line-symmetric shape or a point-symmetric shape with the bearing axis as the center.
When the front shape of the flange for mounting the vehicle body is such a shape, the shape of the fixed side member is simplified, and variations in temperature distribution and expansion / shrinkage due to the complexity of the shape of the fixed side member can be reduced. . Thereby, the influence by the variation in the temperature distribution and the expansion / contraction amount in the fixed member can be sufficiently reduced, and the load detection sensor unit can detect the strain amount due to the load.

In the present invention, a surface treatment having corrosion resistance or corrosion resistance may be applied to at least a contact portion of the outer diameter surface of the stationary member with the plurality of load detection sensor portions. The surface treatment is metal plating, painting, or coating treatment.
As described above, when the outer diameter surface of the fixed side member is subjected to corrosion resistance or anticorrosion surface treatment, the mounting portion of the load detection sensor portion rises due to the rust of the outer diameter surface of the fixed side member, or the load detection It is possible to prevent the sensor unit from generating rust, eliminate the malfunction of the strain sensor due to rust, and accurately detect the load over a long period of time.

In this invention, the outboard side end of the protective cover is fitted to the outer peripheral surface of the stationary member, and a lip portion made of the annular elastic body is provided along the opening edge of the inboard side end of the protective cover. You may make this lip part contact the side surface which faces the outboard side of the flange provided in the said fixed side member, or the outer peripheral surface of the said fixed side member.
Even in this configuration, the sensor can be covered with a protective cover, and the sensor failure due to the influence of the external environment can be prevented, and the load acting on the wheel bearing and the tire ground contact surface can be accurately detected over a long period of time. For example, it is possible to reliably protect the load detection sensor unit from stepping stones, muddy water, salt water, and the like from the outside. Since the protective cover is attached by fitting the outboard side end to the outer peripheral surface of the fixed side member, the protective cover can be easily attached. In addition, the signal cable wiring process and the load detection sensor unit can be easily assembled and the cost can be reduced.
When the stationary member is the outer member, the protective cover is attached to the outer peripheral surface of the outer member. In this case, the protective cover is easy to attach, and the load detection sensor unit is protected by the protective cover. Easy to do.

  In the case of this configuration, a hole portion from which the lead portion of the signal cable is pulled out from the protective cover is provided at an inboard side end portion of the protective cover, and a seal material is provided at a portion where the signal cable lead portion is pulled out from the hole portion. May be applied. As a result, waterproofing and dustproofing can be reliably performed at the signal cable lead-out portion.

Further, the outboard side end of the protective cover may be protruded to the outboard side from the fixed side member, and a non-contact seal gap may be formed between the outboard side end and the rotating side member.
In the case of this configuration, since the non-contact sealing gap is sealed between the protective cover and the rotation side member, the sealing performance can be improved without increasing torque.

  In this case, the outboard side end of the protective cover may be shaped along the rotation side member. In the case of this configuration, the non-contact seal gap formed between the outboard side end of the protective cover and the rotation side member has a higher sealing performance.

In this invention, the inboard side end of the protective cover is fitted to the outer diameter surface of the flange for mounting on the vehicle body provided on the fixed side member, and along the opening edge of the outboard side end of the protective cover. A lip portion made of the annular elastic body may be provided, and this lip portion may be brought into contact with the outer peripheral surface of the stationary member or the surface of the rotating member of the outer member and the inner member.
In this way, when the inboard side end of the protective cover is fitted to the outer diameter surface of the flange for mounting on the vehicle body provided on the stationary member, the protective cover can be easily attached. . Moreover, since the lip is provided on the protective cover, it is not necessary to attach the sealing means such as the lip portion separately from the protective cover, and the attaching work of the sealing means can be reduced.
When the stationary member is an outer member, the protective cover is attached to the outer periphery of the outer member. In this case, the protective cover can be more easily attached and the sensor can be easily protected by the protective cover.

  In the case of this configuration, the lip portion may have a shape in which the distal end gradually extends toward the outboard side and extends, and the lip portion may be brought into contact with the outer peripheral surface of the fixed side member. In the case of this configuration, the intrusion of muddy water, salt grooves, and the like from the outboard side end into the protective cover can be more reliably prevented.

  Moreover, it is good also as a cover outer peripheral surface coating | coated part by extending a part of lip part to a part of outer peripheral surface of the said protective cover. When the lip portion is attached to the outer peripheral surface of the protective cover, the cover outer peripheral surface covering portion extends further to the inboard side than the range positioned on the outer peripheral surface of the protective cover in order to obtain the strength required for the attachment. Provide. In the case of this configuration, at the end on the outboard side of the outer peripheral surface of the protective cover, a wall made of the cover outer peripheral surface covering portion projects to the outer diameter side, and this wall causes the lip portion to become the outer peripheral surface of the outer member. Muddy water, salt water, etc. can be prevented from flowing into the abutting part. Therefore, intrusion of muddy water, salt water, etc. into the protective cover can be prevented more reliably.

  In this invention, it is good also considering the outer peripheral surface of the cover outer peripheral surface coating | coated part of the said lip | rip part as an inclined surface which diameter-expands toward an outboard side. In this configuration, it is possible to prevent the muddy water / salt water or the like from flowing into the portion where the lip portion is in contact with the outer peripheral surface of the outer member, and it is possible to more reliably prevent the muddy water / salt water etc. from entering the protective cover.

In this invention, the outboard side end of the protective cover may be projected to the outboard side from the fixed side member, and a non-contact seal gap may be formed between the outboard side end and the rotating side member. . The “non-contact seal gap” in this specification refers to a gap that is narrow enough to prevent water or the like from entering in a state where relative rotation between the stationary member and the rotating member occurs.
In the case of this configuration, a seal between the protective cover and the fixed side member is formed between the contact of the lip portion with the outer peripheral surface of the fixed side member and between the outboard side end of the protective cover and the rotating side member. Since it is made of a double sealed structure with a non-contact seal, the seal on the outboard side is more secure, and sensor failure due to the influence of the external environment is more reliably prevented, and load detection is performed accurately. be able to.

In this invention, the said rotation side member has a hub flange for wheel attachment, and you may make the said lip part contact the side surface which faces the inboard side of this hub flange.
In this configuration, since the gap between the hub flange of the rotating side member and the outboard side end of the protective cover is sealed by the lip part, it is ensured that muddy water, salt water, etc. enter the protective cover from the outboard side end. Can be prevented.

  In the present invention, an electronic component including the load detection sensor unit, a signal processing IC for processing an output signal of the load detection sensor unit, and a signal cable for extracting the processed output signal to the outside of the bearing is ringed. A sensor assembly connected in a shape may be attached to the outer peripheral surface of the fixed side member concentrically with the fixed side member, and the sensor assembly may be covered with the protective cover. In this configuration, the electronic component can be covered with the protective cover together with the sensor assembly.

  In this invention, the protective cover may be a molded product obtained by pressing a corrosion-resistant steel plate. The protective cover may be formed by pressing a corrosion-resistant steel plate and performing metal plating or coating treatment on the surface thereof. In these configurations, the protective cover can be prevented from being corroded by the external environment.

  In the present invention, the lip portion may be integrally formed with the protective cover. If the lip portion is formed integrally, the labor of manufacturing the lip portion as a separate part and assembling it to the protective cover can be saved. The elastic body constituting the lip portion may be made of a rubber material. When the elastic body constituting the lip portion is a rubber material, the sealing performance of the inboard side end of the protective cover can be ensured.

In this invention, the estimation means may calculate the amplitude of the output signal or a value corresponding to the amplitude from the difference between the output signals of the two or more sensors.
The amplitude of the output signal is influenced by the passage of the rolling element and the position of the rolling element, and the output signal fluctuates due to the influence of temperature and the effect of slippage between the knuckle and flange surfaces. Therefore, by calculating the amplitude of the output signal or the value corresponding to the amplitude from the difference between the output signals, at least the effect of temperature on each output signal and the effect of slippage between the knuckle and flange surfaces can be offset and detected. The accuracy can be increased.
The “temperature influence” means that the output signal shifts due to the temperature change of the bearing. The “slip effect” is a shift of an output signal caused by a change in load applied to the bearing.
(1) When the temporal change of the shift factor is moderate, specifically, when it is lower than the rolling element frequency, the apparent amplitude width is equivalent to the amplitude width obtained by the calculation. That is, it appears that the center position of the amplitude has changed.
(2) When the temporal change of the shift factor is the same as the frequency of the rolling element, the apparent amplitude range is (actual amplitude) + (variation due to the shift factor).
(3) When the temporal change of the shift factor is higher than the frequency of the rolling element, the apparent amplitude frequency appears not to be due to the passage of the rolling element but to the change of the shift factor.
These shift factors are input in phase to two adjacent output signals. Therefore, by taking the difference between the two sensors, the influence can be removed and a pure amplitude can be detected.

The estimation means may generate an absolute value of the signal from the difference between the output signals, and use the peak value or the direct current component as the amplitude equivalent value of the output signal.
The estimation means may calculate an effective value of the signal from the difference between the output signals and set the value as an amplitude equivalent value of the output signal.
The estimation means may obtain a maximum value and a minimum value within a time interval of one or more periods of the vibration period from the difference between the output signals, and use the values as the amplitude equivalent value of the output signal.
Even if the estimation means performs any of the above processes, the amplitude equivalent value can be obtained with high accuracy and simple calculation.

In this invention, among the two or more contact fixing parts, the interval between two contact fixing parts located at both ends of the circumferential arrangement of the outer diameter surface of the fixed side member is made the same as the arrangement pitch of the rolling elements. Also good.
In the case of this configuration, if, for example, two sensors are arranged at an intermediate position between the two contact fixing portions, the circumferential interval between the two sensors is approximately 1 / (1) of the arrangement pitch of the rolling elements. 2. As a result, the output signals of both sensors have a phase difference of approximately 180 degrees, and the difference is a value that sufficiently offsets the influence of temperature and the influence of slippage between the knuckle and flange surfaces. Thereby, the force acting between the wheel bearing and the wheel and the road surface estimated by the estimating means becomes accurate with the effect of temperature and the effect of slippage between the knuckle and the flange surface more reliably eliminated.

In this invention, the interval in the circumferential direction of the outer diameter surface of the fixed member between adjacent sensors in the two or more sensors is {1/2 + n (n: integer)} times the arrangement pitch of the rolling elements. Or it is good also as a value approximated to these values.
When the circumferential interval between two sensors is ½ of the arrangement pitch of the rolling elements, the output signals of these sensors have a phase difference of 180 degrees, and the difference is the temperature It is a value that offsets the effects of sliding and the effects of slippage between the knuckle and flange surfaces. Thereby, the force acting between the wheel bearing and the wheel and the road surface estimated by the estimating means becomes accurate with the effect of temperature and the effect of slippage between the knuckle and the flange surface more reliably eliminated.

In the present invention, the load detection sensor unit includes three contact fixing units and two sensors, and is adjacent between the first and second contact fixing units adjacent to each other and between the second and third contact fixing units adjacent to each other. Each sensor may be attached between the two.
In the case of this configuration, when the circumferential interval between the two contact fixing portions (the first contact fixing portion and the third contact fixing portion) located at both ends is the same as the arrangement pitch of the rolling elements. The interval in the circumferential direction between two adjacent sensors is ½ of the arrangement pitch of the rolling elements. As a result, the force acting between the wheel bearing and the wheel and the road surface estimated by the estimating means is accurate without the influence of temperature and the effect of slippage between the knuckle and the flange surface.

  In the case of this configuration, the interval in the circumferential direction of the outer diameter surface of the fixed member of the adjacent contact fixing portion or the adjacent sensor is {1/2 + n (n: integer)} times the arrangement pitch of the rolling elements. Or it is good also as a value approximated to these values. Also in this configuration, the influence of temperature and the influence of slippage between the knuckle and the flange surface can be eliminated by the difference between the output signals of the sensors.

In the present invention, the strain generating member may be formed of a strip having a uniform planar width, or a thin plate material having a planar planar shape and having a notch in the side portion.
As described above, when the strain generating member is formed of a thin plate material having a planar shape with a uniform width, the strain generating member can be made compact and low cost.

  In the present invention, the load detection sensor portions are arranged 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 fixed side member that are in a vertical position and a horizontal position with respect to the tire ground contact surface. Also good. In the case of this configuration, loads in a plurality of directions can be estimated. That is, the vertical direction load Fz and the axial direction load Fy can be estimated from the output signals of the two load detection sensor portions arranged on the upper surface portion and the lower surface portion on the outer diameter surface of the fixed side member. The load Fx caused by the driving force or the braking force can be estimated from the output signals of the two load detecting sensor portions arranged on the right surface portion and the left surface portion.

In this invention, the estimation means may further estimate the load acting on the wheel bearing using the sum of the output signals of the two or more sensors.
If the sum of the output signals of two or more sensors is taken, the influence of the position of the rolling element appearing in each output signal can be canceled out, so that the load can be estimated even when stationary. Coupled with the fact that the effect of temperature and the effect of slippage between the knuckle and flange surfaces can be eliminated from the difference, the load can be detected with higher accuracy and a low-pass filter is not required, thereby improving the response speed.

In this invention, there are three contact fixing parts of the strain generating member in the load detecting sensor part, and the three contact fixing parts in the belt-like strain generating member are the same on the outer diameter surface of the fixed side member. An axial position and a position spaced apart from each other in the circumferential direction, and an interval between adjacent contact fixing portions or an interval in the circumferential direction of the outer diameter surface of the fixed side member of the adjacent sensor. , {1/2 + n (n: integer)} times the arrangement pitch of the rolling elements or a value approximating these values, and the estimating means acts on the wheel bearing according to the difference between the output signals of the two sensors. It is good also as what estimates the load to do.
To summarize, this sensor-equipped wheel bearing has an outer member in which a double row rolling surface is formed on the inner periphery, and an inner member in which the rolling surface opposite to the rolling surface is formed on the outer periphery. A wheel bearing including a member and a double row rolling element interposed between the rolling surfaces of the two members opposed to each other, wherein the wheel is rotatably supported with respect to the vehicle body, of the outer member and the inner member. A strain generating member having three contact fixing portions fixed to the fixed side member in contact with the fixed side member, and two sensors attached to the strain generating member and detecting the strain of the strain generating member. A sensor-equipped wheel bearing provided with a plurality of load detection sensor sections, wherein the plurality of load detection sensor section strain generating members are continuously formed over the plurality of load detection sensor sections. This band-shaped distortion generating part The three contact fixing portions are arranged at the same axial position on the outer diameter surface of the fixed side member and at positions spaced apart from each other in the circumferential direction, and the adjacent contact fixing portions are spaced or adjacent to each other. The interval in the circumferential direction of the outer diameter surface of the fixed side member of the sensor is set to {1/2 + n (n: integer)} times the arrangement pitch of the rolling elements or a value approximating these two values. An estimation means for estimating a load acting on the wheel bearing may be provided based on the difference between the output signals of the sensors.

According to this configuration, the difference between the output signals of the two sensors cancels out the influence of temperature and the effect of slippage between the knuckle and the flange surface. The load acting between the tire and the road surface can be detected with high accuracy.
In particular, since the strain generating members of the plurality of load detecting sensor portions are one band-like strain generating member continuous across the plurality of load detecting sensor portions, no complicated wiring work is required. Quality improvement and cost reduction are possible.

In the method for assembling a sensor-equipped wheel bearing according to the present invention, a plurality of loads are applied to the outer peripheral surface of the fixed-side member in a single state of the fixed-side member or in a state where the rolling element is assembled to the fixed-side member. The belt-shaped strain generating member constituting the detection sensor portion is attached, the protective cover is press-fitted into the outer peripheral surface of the stationary member, and then the bearing is assembled.
According to this assembling method, the sensor-equipped wheel bearing in which the load detection sensor portion attached to the fixed member is covered with the protective cover can be easily assembled.

An in-wheel motor-equipped wheel bearing device according to the present invention includes the sensor-equipped wheel bearing according to any one of the above-described configurations of the present invention.
According to this configuration, when the wheel bearing with sensor of the present invention is applied to the in-wheel motor built-in wheel bearing apparatus, each effect of the present invention is more effectively exhibited.

  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 Further, a strain generating member having two or more contact fixing portions fixed in contact with the fixed side member, and two or more sensors attached to the strain generating member and detecting the strain of the strain generating member A sensor-equipped wheel bearing provided with a plurality of load detection sensor units, wherein an estimation means for estimating a load acting on the wheel bearing is provided based on a difference between output signals of the two or more sensors. These strain generating members of the load detection sensor One band-like strain generating member continuous over a number of load detecting sensor portions, and the two or more contact fixing portions in the band-like strain generating member are arranged in the same axial direction of the outer diameter surface of the fixed side member It is arranged so that it is at a position and spaced apart from each other in the circumferential direction, and a plurality of load detection sensor parts are covered with a cylindrical protective cover surrounding the outer periphery of the fixed side member, and one of the axial directions of this protective cover One end is fitted to the outer periphery of the fixed side member, and an annular seal member made of an elastic body is provided at the opening edge of the other end. The seal member is provided on the surface of the fixed side member, or the outer member and the inner member. Because it is in contact with the surface of the rotating side member, it is possible to improve the quality and reduce the cost of the wiring part, and to protect the sensor from collisions such as pebbles jumping during traveling. Yes, from outside Can be prevented from entering the sensor such as muddy water is, long-term becomes possible to stably sensing.

  Since the in-wheel type motor-equipped wheel bearing device of the present invention includes the sensor-equipped wheel bearing having any one of the above-described configurations of the present invention, each effect of the sensor-equipped wheel bearing of the present invention is effective. As a result, no complicated wiring work is required for the sensor, the quality of the wiring part can be improved and the cost can be reduced, and the sensor can be protected from collisions such as pebbles that bounce while driving, and from the outside. Intrusion of muddy water into the sensor can be prevented, and stable sensing can be performed for a long period of time.

It is a figure showing combining the sectional view of the bearing for wheels with a sensor concerning a 1st embodiment of this invention, and the block diagram of the conceptual composition of the detection system. It is explanatory drawing of the sensor assembly which looked at the outward member of the wheel bearing with a sensor from the outboard side. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2. FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. 2. It is a VV arrow sectional view of Drawing 1. It is an expanded top view of the sensor assembly in the wheel bearing with a sensor. It is an enlarged plan view of the sensor part for load detection in the sensor assembly. It is VIII-VIII arrow sectional drawing in FIG. It is sectional drawing which shows the other example of installation of the sensor part for load detection. It is explanatory drawing of the influence of a rolling-element position with respect to the output signal of the sensor part for load detection. It is another explanatory drawing of the influence of the rolling element position with respect to the output signal of the sensor part for load detection. It is another explanatory drawing of the influence of the rolling element position with respect to the output signal of the sensor part for load detection. It is another explanatory drawing of the influence of the rolling element position with respect to the output signal of the sensor part for load detection. FIG. 6 is a partially omitted sectional view of a sensor-equipped wheel bearing according to another embodiment of the present invention. It is sectional drawing of the bearing for wheels with a sensor concerning further another embodiment of this invention. It is a partial expanded sectional view of FIG. It is sectional drawing of the bearing for wheels with a sensor concerning further another embodiment of this invention. It is a partial expanded sectional view of FIG. It is sectional drawing of the bearing for wheels with a sensor concerning further another embodiment of this invention. It is a partial expanded sectional view of FIG. It is sectional drawing of the bearing for wheels with a sensor concerning further another embodiment of this invention. It is the elements on larger scale of FIG. It is sectional drawing of the bearing for wheels with a sensor concerning further another embodiment of this invention. It is a partial expanded sectional view of FIG. It is sectional drawing of the bearing for wheels with a sensor concerning further another embodiment of this invention. It is a partial expanded sectional view of FIG. It is sectional drawing of the bearing for wheels with a sensor concerning further another embodiment of this invention. It is a partial expanded sectional view of FIG. It is sectional drawing of the bearing for wheels with a sensor concerning further another embodiment of this invention. It is a partial expanded sectional view of FIG. It is sectional drawing of the bearing for wheels with a sensor concerning further another embodiment of this invention. It is a partial expanded sectional view of FIG. It is sectional drawing of the bearing for wheels with a sensor concerning further another embodiment of this invention. It is a partial expanded sectional view of FIG. It is sectional drawing which shows the outline | summary of the in-wheel type motor built-in wheel bearing apparatus using the bearing for wheel with a sensor of FIG. It is an expansion | deployment top view which shows the structure of the sensor assembly in a prior art example. It is an expansion | deployment top view which shows the structure of the sensor assembly in another prior art example. It is sectional drawing which shows the attachment structure of the protective cover in the prior art example. It is explanatory drawing of the protection cover.

  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 (not shown) in the suspension device of the vehicle body on the outer periphery, and the whole is an integral part. The flange 1a is provided with bolt holes 14 for attaching knuckles at a plurality of locations in the circumferential direction. Knuckle bolts (not shown) inserted into the bolt insertion holes (not shown) of the knuckle from the inboard side are formed in the bolt holes 14. By screwing, the body mounting flange 1a is attached to the knuckle.
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-fit holes 16 for hub bolts 15 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 assembly 31 for load detection is provided on the outer periphery of the outer member 1, and this sensor assembly 31 is covered with a cylindrical protective cover 29 surrounding the outer periphery of the outer member 1.

  FIG. 5 shows a cross-sectional view taken along the arrow VV in FIG. FIG. 1 shows a cross-sectional view taken along the line II in FIG. As shown in FIG. 5, the vehicle body mounting flange 1a has a front shape that is a line segment perpendicular to the bearing axis O (for example, a shape that is line symmetric with respect to the vertical line segment LV or the horizontal line segment LH in FIG. The shape is point-symmetric with respect to the bearing axis O. Specifically, in this example, the front shape is circular.

  Four load detection sensor portions 20 are provided on the outer diameter surface of the outer member 1 which is a fixed member. Here, these load detection sensor units 20 are provided 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 are in the vertical position and the front-rear position with respect to the tire ground contact surface. ing.

  Each of these load detection sensor units 20 includes a strain generating member 21 and a strain of the strain generating member 21 attached to the strain generating member 21, as shown in an enlarged plan view and an enlarged sectional view in FIGS. Are two or more (two here) strain sensors 22 (22A, 22B). In the figure, the reference numerals “22A, 22B” are assigned to the strain sensors. However, when there is no need to distinguish between the two strain sensors, they may be referred to as “strain sensors 22”. The strain generating member 21 of the load detection sensor unit 20 is a single band-shaped member that is continuous over the plurality of load detection sensor units 20 as shown in a development plan view in FIG. 6. This strain generating member 21 is made of an elastically deformable metal such as a steel material and is made of a thin plate material of 2 mm or less, and the plane outline is a strip having a uniform width over the entire length. Two slit-shaped cutout portions 21b extending in the width direction are provided in parallel in the portion. Here, the notch portion 21b on one side portion of the strain generating member 21 is formed by cutting directly in the width direction from the side portion, but the notch portion 21b on the other side portion is formed by the strain generating member. 21 is formed by cutting in the width direction from a middle portion of a slit 21c formed to extend in the longitudinal direction. The corner of the notch 21b has an arcuate cross section. In addition, the strain generating member 21 has two or more (three in this case) contact fixing portions 21 a that are fixed to the outer diameter surface of the outer member 1 in contact with each position of the load detecting sensor portion 20. 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 affixed to locations where the strain increases with respect to the load in each direction in the strain generator 21. Specifically, it arrange | positions between the contact fixing | fixed parts 21a adjacent on the outer surface side of the distortion generation member 21. FIG. That is, in FIG. 8, one strain sensor 22A is arranged between the contact fixing portion 21a at the left end and the contact fixing portion 21a at the center, and the other between the contact fixing portion 21a at the center and the contact fixing portion 21a at the right end. One strain sensor 22B is arranged. As shown in FIG. 7, the notch portions 21 b are formed at two positions corresponding to the placement portions of the strain sensors 22 </ b> A and 22 </ b> B on both side portions of the strain generating member 21. Thereby, the strain sensor 22 detects the strain in the longitudinal direction around the notch 21 b of the strain generating member 21. 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 load detection sensor unit 20 and affects the measurement of strain.

  Each load detecting sensor unit 20 has three contact fixing parts 21a of the strain generating member 21 at positions having the same dimension in the axial direction of the outer member 1, and the contact fixing parts 21a are arranged in the circumferential direction. It arrange | positions so that it may come to a distant position, and these contact fixing | fixed parts 21a are each fixed to the outer-diameter surface of the outer member 1 with the volt | bolt 24 which is a fixing tool. In order to stably fix the load detection sensor 20 to the outer diameter surface of the outer member 1, a flat portion 1 b is formed at a place where the contact fixing portions 21 a on the outer diameter surface of the outer member 1 are contact-fixed. Is done. Each of the bolts 24 is screwed into a bolt hole 27 of a female screw provided on the outer peripheral portion of the outer member 1 from a bolt insertion hole 25 provided in the contact fixing portion 21a in a radial direction. A groove 1c is provided in each of the three intermediate portions to which the three contact fixing portions 21a of the strain generating member 21 are fixed on the outer diameter surface of the outer member 1. Thus, by fixing the contact fixing portion 21 a to the outer diameter surface of the outer member 1, each portion having the notch portion 21 b in the thin plate-like strain generating member 21 is separated from the outer diameter surface of the outer member 1. It becomes a separated state, 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 addition, as shown in a cross-sectional view in FIG. 9, the three contact fixing portions 21 a of the strain generating member 21 are fixed to the outer diameter surface of the outer member 1 by bolts 24 via spacers 23, respectively. The formation of the groove 1c on the outer diameter surface of the member 1 may be omitted, and the portions where the notches 21b of the strain generating member 21 are located may be separated from 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.

  As shown in FIG. 5, the strain generating member 21, which is one continuous belt-like member across the four load detection sensor units 20, has a plurality of locations (here, the intermediate positions of the adjacent load detection sensor units 20). 6 places) is a bent portion 21d bent in one direction, and is attached to the outer member 1 so as to surround the outer periphery of the outer member 1 as shown in FIG. The strain generating member 21 includes a signal processing IC 28 for processing an output signal from the strain sensor 22 of each load detection sensor unit 20, a signal cable 33 for taking out the processed signal to the outside, and a signal processing IC 28. And a connector 34 for connecting the signal cable 33 is provided. Each strain sensor 22 in the four load detection sensor units 20 is connected to the signal processing IC 28 by a circuit pattern (not shown) for wiring provided on the strain generating member 21. As described above, the four load detection sensor units 20, the strain generation member 21 continuous over the load detection sensor units 20, the signal processing IC 28 provided separately in the strain generation member 21, and the signal cable 33, , The connector 34 is combined to form a sensor assembly 31 which is an integrated electronic component, and the sensor assembly 31 is attached to the outer diameter surface of the outer member 1 to thereby form a sensor. A wheel bearing is constructed.

  Next, the protective cover 29 will be described with reference to FIGS. The protective cover 29 is a cylindrical member that surrounds the outer periphery of the outer member 1, and the outer end surface of the outer member 1 is a fitting cylindrical portion 29 o whose outboard side end has a smaller diameter than other portions. Can be fitted. The inboard side end of the protective cover 29 is provided with a lip portion 35 made of an annular elastic body along the opening edge as a sealing member, and this lip portion 35 is provided on the flange 1a for mounting the vehicle body of the outer member 1. It can be brought into contact with the side facing the outboard side. Thereby, the space between the outboard side end and the inboard side end of the protective cover 29 and the outer peripheral surface of the outer member 1 is sealed. The lip portion 35 may be brought into contact with the outer peripheral surface of the flange 1a.

  As the elastic body constituting the lip portion 35, a rubber material is desirable. Thereby, the sealing performance of the inboard side end of the protective cover 29 by the lip portion 35 can be ensured. In addition, the lip portion 35 may be integrally formed with the protective cover 29. Here, as shown in an enlarged sectional view in FIG. 3, the lip portion 35 has a shape that increases in diameter toward the inboard side. Thereby, infiltration of muddy water, salt water, etc. into the protective cover 29 from the inboard side end can be prevented more reliably.

  The protective cover 29 is formed by, for example, pressing a steel plate having corrosion resistance. Thereby, it can prevent that the protective cover 29 corrodes by an external environment. In addition, the protective cover 29 may be formed by pressing a steel plate, and the surface thereof may be subjected to metal plating or painting. Also in this case, the protective cover 29 can be prevented from being corroded by the external environment. In addition, the material of the protective cover 29 may be plastic or rubber.

  As shown in FIG. 4 showing a cross-sectional view taken along the line IV-IV in FIG. And a sealing material 37 is applied to a portion where the signal cable lead portion 33B is drawn from the hole portion 36. The hole 36 is sealed by the sealing material 37. Thereby, the sealing performance of the part where the signal cable lead-out portion 33B is drawn out from the protective cover 29 can be ensured.

  The assembly of the sensor-equipped wheel bearing is performed according to the following procedure. First, in a state where the outer member 1 is a single body or a state where the rolling member 5 is assembled to the outer member 1, a sensor assembly 31 including an electronic component including the load detection sensor unit 20 on the outer peripheral surface of the outer member 1. Install. Next, the cylindrical protective cover 29 is press-fitted into the outer peripheral surface from the outboard side of the outer member 1 to fit the outer end of the outer board 1 to the outer peripheral surface of the outer member 1. By assembling the lip portion 35 at the inboard side end to the side surface or the outer peripheral surface of the outer member 1 facing the outboard side of the vehicle body mounting flange 1a, a sensor assembly comprising an electronic component including the load detection sensor portion 20 is provided. The product 31 is covered with a protective cover 29. After this, the entire bearing is assembled. By assembling in this procedure, the sensor-equipped wheel bearing with the protective cover 29 covering the load detecting sensor unit 20 attached to the outer member 1 or the sensor assembly 31 including the load detecting sensor unit 20 can be easily obtained. Can be assembled into.

The operation and specific configuration of the load detection sensor unit 20 will be described. The output signals of the two strain sensors 22 (22A, 22B) of each load detection sensor unit 20 are input to the vehicle-side estimation means 32 (FIG. 1) via the signal processing IC 28 and the signal cable 33. The estimation means 32 determines the force (vertical load Fz, driving force, etc.) acting on the wheel bearings and between the wheel and the road surface (tire contact surface) from the output signals of the two strain sensors 22A, 22B of the load detection sensor unit 20. This is a means for estimating the load Fx and the axial load Fy) as braking force. In this embodiment, the estimation means 32 estimates the acting forces Fx, Fy, and Fz from the difference between the output signals of the two strain sensors 22A and 22B (specifically, the amplitude of the output signal). The estimation means 32 uses a calculation formula or a table or the like to determine the relationship between the vertical load Fz, the load Fx as a driving force or braking force, the axial load Fy, and the difference between the output signals of the two strain sensors 22A and 22B. It has a set relationship setting means (not shown), and using the relationship setting means based on the difference between the output signals of the two strain sensors 22A and 22B, the acting force (vertical load Fz, load that becomes driving force or braking force) Fx and axial load Fy) are estimated. The setting contents of the relationship setting means are obtained by a test or simulation in advance.
The estimation means 32 is not limited to the difference between the output signals, and for example, based on information such as the sum of the output signals of the two strain sensors 22A and 22B, the average value, the amplitude value, and the amplitude center value. For example, the acting forces Fx Fy and Fz may be estimated using a linear combination, for example. Also in this case, a relationship setting means in which the relationship between the information such as the sum and the average value and the respective acting forces Fx Fy, Fz is set by an arithmetic expression or a table may be used.

  Since the load detection sensor unit 20 is provided at an axial position around the rolling surface 3 of the outboard side row of the outer member 1, the output signals of the strain sensors 22A and 22B are as shown in FIG. It is influenced by the rolling element 5 that passes through the vicinity of the installation portion of the detection sensor unit 20. 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 load detection sensor unit 20 (or when the rolling element 5 is at that position), the output signals A and S of the strain sensors 22A and 22B, B becomes the maximum value, and decreases as the rolling element 5 moves away from the position as shown in FIGS. 10B and 10C (or when the rolling element 5 is located away from the position). When the bearing rotates, the rolling elements 5 sequentially pass through the vicinity of the installation portion of the load detection sensor unit 20 at a predetermined arrangement pitch P. Therefore, the output signals A and B of the strain sensors 22A and 22B are output from the arrangement of the rolling elements 5. As shown by a solid line in FIG. 10C, the pitch P is a period, and the waveform is close to a sine wave that changes periodically. Further, the output signals A and B of the strain sensors 22A and 22B are affected by temperature and hysteresis due to slippage between the surfaces of the knuckle and the vehicle body mounting flange 1a (FIG. 1).

  In this embodiment, by calculating the difference between the output signals A and B of the two strain sensors 22A and 22B, the force that the estimating means 32 acts on the wheel bearings or between the wheel and the road surface (tire contact surface) ( Since the vertical load Fz, the driving force and the braking force Fx, and the axial load Fy) are estimated, the influence of the temperature appearing in the output signals A and B of the two strain sensors 22A and 22B, the knuckle The effect of slippage between the flange surfaces can be offset, and thereby the load acting on the wheel bearing and the tire ground contact surface can be accurately detected.

The difference calculation process will be described.
As a method of obtaining the amplitude of the difference signal or a value corresponding to the amplitude from the difference between the output signals A and B of the two strain sensors 22A and 22B by calculation processing, the peak value is obtained from the absolute value | A−B |. It may be detected. The absolute value | A−B | may be generated by an arithmetic circuit or may be calculated by digital arithmetic processing. Since a half-wave rectified waveform is obtained in the rotating state, the peak value can be held, or a DC component can be obtained by a low-pass filter; Further, the effective value (root mean square value) of the difference signal (A−B) may be used as an amplitude equivalent value in the load estimation calculation. In the digital calculation processing, one or more vibration periods of the difference signal may be set as a calculation target section, and the amplitude equivalent value may be calculated by detecting the maximum value and the minimum value in the section.

  In FIG. 10 showing the configuration example of FIG. 8 as the load detection sensor unit 20, among the three contact fixing units 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 of the array is set to be the same as the array 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 difference sufficiently offsets the influence of temperature and the effect of slippage between the knuckle and flange surfaces. Value. As a result, the force acting on the wheel bearings and the distance between the wheel and the road surface (tire contact surface) (vertical load Fz, The load Fx and the axial load Fy) serving as the driving force and braking force are accurate with the effect of temperature and the effect of slippage between the knuckle and flange surfaces more reliably eliminated.

In FIG. 11, in the load detection sensor unit 20 of the configuration example of FIG. 8, the circumferential interval between the two strain sensors 22 </ b> A and 22 </ b> B is ½ of the arrangement pitch P of the rolling elements 5. An example of setting is shown. In this example, since the circumferential interval between the two strain sensors 22A and 22B is ½ of the arrangement pitch P of the rolling elements 5, the output signal A of the two strain sensors 22A and 22B. , B have a phase difference of 180 degrees, and the difference is a value that completely cancels the influence of temperature and the effect of slippage between the knuckle and flange surfaces. Thus, from the wheel bearings estimated by the estimating means 32 and the forces acting on the wheel and the road surface (tire contact surface) (vertical load Fz, driving force and braking force Fx, axial load Fy), It is possible to more reliably eliminate the effects of temperature and sliding effects such as between the knuckle and flange surfaces.
In this case, the circumferential distance between the two strain sensors 22A and 22B is {1/2 + n (n: integer)} times the arrangement pitch P of the rolling elements 5, or a value approximated to these values. It is also good. Also in this case, the difference between the output signals A and B of the two strain sensors 22A and 22B is a value that offsets the influence of temperature and the influence of slippage between the knuckle and flange surfaces.

FIG. 12 shows a configuration example in which the contact fixing portion 21a at the intermediate position is omitted and two contact fixing portions 21a are provided in the configuration example of FIG. 8 as the load detecting sensor unit 20 (FIG. 12A). ). In this case, similarly to the example of FIG. 10, the interval between the two contact fixing portions 21 a is set to be the same as the arrangement pitch P of the rolling elements 5. Accordingly, the circumferential interval between the two strain sensors 22A and 22B disposed between the two 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 difference sufficiently offsets the influence of temperature and the effect of slippage between the knuckle and flange surfaces. Value. As a result, the force acting on the wheel bearings and the distance between the wheels and the road surface (tire contact surface) (vertical load Fz, F), which is estimated by the estimating means 32 from the difference between the output signals A and B of the two strain sensors 22A and 22B. The load Fx and the axial load Fy) serving as the driving force and braking force are accurate with the effect of temperature and the effect of slippage between the knuckle and flange surfaces more reliably eliminated.
In FIG. 13, in the load detection sensor unit 20 of the configuration example of FIG. 12A, the circumferential interval between the two strain sensors 22 </ b> A and 22 </ b> B is 1 of the arrangement pitch P of the rolling elements 5. An example of setting to / 2 is shown. In this example as well, as in the example of FIG. 11, the output signals A and B of the two strain sensors 22A and 22B have a phase difference of 180 degrees, and the difference is influenced by the temperature and knuckle flange. It is a value that completely cancels out the effects of slippage between surfaces. Thus, from the wheel bearings estimated by the estimating means 32 and the forces acting on the wheel and the road surface (tire contact surface) (vertical load Fz, driving force and braking force Fx, axial load Fy), It is possible to more reliably eliminate the effects of temperature and sliding effects such as between the knuckle and flange surfaces.

  In this case, the circumferential interval between the two strain sensors 22A and 22B may be {1/2 + n (n: integer)} times the arrangement pitch P of the rolling elements 5, or a value approximate to these values. . Also in this case, the difference between the output signals A and B of the two strain sensors 22A and 22B is a value that offsets the influence of temperature and the influence of slippage between the knuckle and flange surfaces.

  In addition, in FIGS. 10 and 11, the circumferential interval between two adjacent contact fixing portions 21a is {1/2 + n (n: integer)} times the arrangement pitch P of the rolling elements 5, Or it is good also as a value approximated to these values. Also in this case, the difference between the output signals A and B of the two adjacent strain sensors 22A and 22B is a value that cancels out the influence of temperature and the influence of slippage between the knuckle and flange surfaces.

  According to the wheel bearing with sensor having the above-described configuration, when a load acts between the wheel bearing or the wheel tire and the road surface, the load is also applied to the outer member 1 that is a stationary member of the wheel bearing and the deformation is caused. Arise. Since the three contact fixing portions 21 a of the strain generating member 21 having the notch portion 21 b in the load detecting sensor portion 20 are fixed in contact with the outer member 1, the strain of the outer member 1 expands to the strain generating member 21. The strain is detected by the strain sensors 22A and 22B with high sensitivity, and the load can be estimated from the output signal. Here, the vertical load Fz and the axial load Fy can be estimated from the output signals of the two load detection sensor units 20 arranged on the upper surface portion and the lower surface portion of the outer diameter surface of the outer member 1, and the outer member 1. The load Fx caused by the driving force or the braking force can be estimated from the output signals of the two load detection sensor units 20 arranged on the right surface portion and the left surface portion of the outer diameter surface.

  In this case, the output signals A and B of the strain sensors 22A and 22B in each load detection sensor unit 20 are influenced by temperature and slippage between the knuckle and the flange surface as described above. 32, from the difference between the two output signals, the load acting between the wheel bearing and the tire of the wheel and the road surface (vertical load Fz, load Fx serving as driving force or braking force, axial load Fy) is estimated. Therefore, the influence of temperature and the influence of slippage between the knuckle and flange surfaces are eliminated, and the load can be estimated with high accuracy.

  In particular, in this wheel bearing with sensor, the strain generating member 21 of the plurality of load detection sensor units 20 is formed of a single belt-like member that is continuous over the plurality of load detection sensor units 20. Therefore, it is possible to improve the quality of the wiring section and reduce the cost.

  Further, in this embodiment, the strain generating member 21 is bent at a plurality of positions in the longitudinal direction and fixed to the outer member 1 which is a fixed side member. Work becomes easy.

  If the axial dimension of each contact fixing portion 21a of the load diameter sensor portion 20 fixed to the outer diameter surface of the outer member 1 which is a fixed side member is different, the contact fixing portion 21a from the outer diameter surface of the outer member 1 is different. The strain transmitted to the strain generating member 21 via the difference is also different. In this embodiment, since each contact fixing portion 21a of the load detection sensor portion 20 is provided so as to have the same dimension in the axial direction with respect to the outer diameter surface of the outer member 1, the strain generating member 21 is distorted. Becomes easier to concentrate, and the detection sensitivity is improved accordingly.

  Further, in this embodiment, the strain generating member 21 of the load detecting sensor unit 20 is made of a strip having a uniform planar width, or a thin plate material having a planar planar shape and a notch 21b on the side. Therefore, the distortion of the outer member 1 is easily transmitted to the distortion generating member 21, and the distortion is detected with high sensitivity by the distortion sensors 22A and 22B, and the hysteresis generated in the output signals A and B is also reduced. The load can be estimated with high accuracy. Further, the shape of the strain generating member 21 is also simple, and it can be made compact and low cost.

  In addition, since the corner of the notch 21b of the strain generating member 21 has an arcuate cross section, strain does not concentrate on the corner of the notch 21b, and the possibility of plastic deformation is reduced. Distortion does not concentrate at the corners of the notch portion 21b, so that variation in strain distribution at the detection portion of the strain generating member 21, that is, the attachment portion of the strain sensors 22A and 22B is reduced, and the attachment positions of the strain sensors 22A and 22B are reduced. Affects the output signals A and B of the strain sensors 22A and 22B. Thereby, the load can be estimated with higher accuracy.

  In particular, according to the wheel bearing with sensor, a plurality of load detecting sensor portions 20 are covered with a cylindrical protective cover 29 surrounding the outer periphery of the outer member 1 that is a fixed member, and the outboard of the protective cover 29 is covered. The side end is fitted to the outer peripheral surface of the outer member 1, and the lip portion 35 made of an annular elastic body provided along the opening edge of the inboard side end of the protective cover 29 is attached to the vehicle body mounting flange of the outer member 1. It is made to contact | abut to the side surface or outer peripheral surface which faces the outboard side of la. For this reason, it is possible to prevent the load detection sensor unit 20 from being damaged due to the external environment (damage due to stepping stones, corrosion due to muddy water, salt water, etc.), the load can be detected accurately over a long period of time, and the signal cable 33 is wired Assembling of the processing and the load detecting sensor unit 20 is easy and the cost can be reduced.

  In this embodiment, the load detection sensor unit 20, the signal processing IC 28 that processes the output signal of the load detection sensor unit 20, and the signal cable 33 that extracts the processed output signal to the outside of the bearing are provided. The included electronic components are connected in a ring shape to form a sensor assembly 31, and the sensor assembly 31 is attached concentrically to the outer member 1 on the outer peripheral surface of the outer member 1 that is a stationary member. The sensor assembly 31 is covered with the protective cover 29. For this reason, not only the load detection sensor unit 20 but also other electronic components such as the signal processing IC 28 and the signal cable 33 constituting the sensor assembly 31 can be protected from failure due to the external environment.

In the above description, the case where the acting force between the wheel tire and the road surface is detected is shown, but 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 can be as well.
By using the detected load obtained from the sensor-equipped wheel bearing for vehicle control of the automobile, it is possible to contribute to stable running of the automobile. In addition, when this sensor-equipped wheel bearing is used, a load sensor can be installed in a compact vehicle, the mass productivity can be improved, and the cost can be reduced.

  Further, in this embodiment, the front shape of the vehicle body mounting flange 1a of the outer member 1 which is a fixed side member is a line segment orthogonal to the bearing axis O as shown in FIG. 5 (for example, the vertical line segment LV in FIG. 5). Alternatively, since the shape is axisymmetric with respect to the horizontal line segment LH) or a shape that is point-symmetric with respect to the bearing axis O (specifically, a circle), the flange 1a of the outer member 1 is simplified, Variations in temperature distribution and expansion / shrinkage due to the complexity of the shape of the outer member 1 can be reduced. Thereby, the influence by the variation in the temperature distribution and the expansion / contraction amount in the outer member 1 that is the fixed side member can be sufficiently reduced, and the load detection sensor unit can detect the strain amount due to the load.

  Further, in this embodiment, the load detection sensor unit 20 is positioned in the axial direction around the rolling surface 3 on the outboard side of the double row rolling surfaces 3 in the outer member 1, that is, relatively installed. Since the space is wide and the tire acting force is transmitted to the outer member 1 via the rolling elements 5 and is disposed at a portion having a relatively large deformation amount, the detection sensitivity is improved, and the load can be estimated with higher accuracy.

  In this embodiment, since the load detection sensor unit 20 is provided on the upper surface portion and the lower surface portion of the outer diameter surface and the right surface portion and the left surface portion of the outer member 1 that is a fixed side member, Even under conditions, the load can be estimated with high accuracy. That is, when the load in a certain direction increases, a portion where the rolling element 5 and the rolling contact surface 3 are in contact with each other and a portion which is not in contact appear with a phase difference of 180 degrees. If 20 is installed with a phase difference of 180 degrees, the load applied to the outer member 1 is always transmitted to one of the load detection sensor portions 20 via the rolling elements 5, and the load is applied to the strain sensors 22A and 22B. Can be detected.

  In the above embodiment, the estimating means 32 estimates the load acting on the wheel bearing from the difference between the output signals A and B of the two or more strain sensors 22A and 22B. Further, the load acting on the wheel bearing may be estimated using the sum of the output signals A and B of the two or more strain sensors 22A and 22B. As described above, when the sum of the output signals A and B of the two or more strain sensors 22A and 22B is taken, the influence of the position of the rolling element 5 appearing in each of the output signals A and B can be offset. Coupled with the ability to eliminate the effects of temperature and the effects of sliding between the knuckle and flange surfaces, the load can be detected with higher accuracy.

  FIG. 14 shows another embodiment of the present invention. In this sensor-equipped wheel bearing, in the embodiment shown in FIGS. 1 to 13, at least the contact portion with the load detection sensor portion 20 on the outer peripheral surface of the outer member 1 to which the load detection sensor portion 20 is attached. A surface treatment layer 38 having corrosion resistance or corrosion resistance is formed. Although the case where the surface treatment layer 38 is formed over the entire outer peripheral surface of the outer member 1 is shown here, the surface treatment layer 38 is formed only on the outer peripheral surface on the outboard side of the vehicle body mounting flange 1a. May be. In addition, in FIG. 14, illustration is abbreviate | omitted about the protective cover 29 of FIG. Further, the surface treatment layer 38 may be provided in the same manner as described above also in each embodiment described below.

  Examples of the surface treatment layer 38 having corrosion resistance or corrosion resistance include a plating layer by metal plating, a coating film by painting, a coating layer by coating, and the like. As the metal plating treatment, treatments such as zinc plating, unichrome plating, chromate plating, nickel plating, chrome plating, electroless nickel plating, Kanigen plating, iron trioxide film (black dyeing), and radient can be applied. As the coating treatment, electrodeposition coating such as cationic electrodeposition coating, anion electrodeposition coating, and fluorine-based electrodeposition coating can be applied. As the coating treatment, ceramic coating such as silicon nitride can be applied.

  Thus, by forming the surface treatment layer 38 having corrosion resistance or corrosion resistance on at least the contact portion of the outer peripheral surface of the outer member 1 that is a fixed side member with the load detection sensor unit 20, The mounting portion of the load detection sensor unit 20 can be prevented from rising due to rust on the outer peripheral surface, or the load detection sensor unit 20 can be prevented from generating rust, and the malfunction of the strain sensors 22A and 22B due to rust can be eliminated. Load detection can be performed accurately over a longer period. Further, when the surface treatment layer 38 is formed on the outer peripheral surface of the outer member 1 to which the sensor assembly 33 including the load detection sensor portion 20 is attached, the attachment portion of the sensor assembly 33 may be swelled with rust. And the malfunction of the strain sensors 22A and 22B due to rust can be further eliminated.

  Further, when the surface treatment layer 38 is formed only on the outboard side of the outer peripheral surface of the outer member 1 relative to the body mounting flange 1a, the rolling surface 3 of the outer member 1 is ground. In addition, the untreated surface of the inboard side end of the outer peripheral surface of the outer member 1 can be held, and the rolling surface 3 can be ground with high accuracy.

  15 and 16 show still another embodiment of the present invention. In the wheel bearing with sensor, in the embodiment shown in FIGS. 1 to 13, the outboard side end of the protective cover 29 protrudes to the outboard side from the outer member 1, and the outboard side end and the rotation side A non-contact seal gap 39, that is, a labyrinth seal is formed between the inner member 2 and the member. Here, as shown in an enlarged cross-sectional view in FIG. 16, an inner bent portion 29 a that is bent toward the inner diameter side along the outboard side end of the outer member 1 is formed on the outboard side end of the protective cover 29. The outer bent portion 29b is folded back from the tip of the inner bent portion 29a to the outer diameter side and overlaps the inner bent portion 29a, and further, the curved surface of the base portion of the hub flange 9a of the inner member 2 from the tip of the outer bent portion 29b. A cylindrical portion 29c extending toward the portion 9aa is formed. As a result, a narrow non-contact seal gap 39 is formed between the portion extending from the outer bent portion 29b to the tubular portion 29c and the base curved surface portion 9aa of the hub flange 9a. Other configurations are the same as those in the embodiment of FIGS.

  Thus, by forming the non-contact seal gap 39 between the outboard side end of the protective cover 29 and the inner member 2, the sealing performance at the outboard side end of the protective cover 29 is improved, and the external environment It is possible to more reliably prevent a sensor failure due to the influence of the load and to accurately detect the load.

  17 and 18 show still another embodiment of the present invention. In this sensor wheel bearing, in the embodiment shown in FIGS. 15 and 16, the cylindrical portion 29c at the tip of the outer bent portion 29b at the outboard side end of the protective cover 29 is shown in an enlarged sectional view in FIG. It is formed in an L-shaped cross section along the side surface of the hub flange 9a. Other configurations are the same as those of the embodiment shown in FIGS.

  In this manner, the cylindrical portion 29c at the tip of the outer bent portion 29b at the end of the outboard side of the protective cover 29 is formed in an L-shaped section along the side surface of the hub flange 9a, so that the cylindrical portion 29c is changed from the outer bent portion 29b. A non-contact seal gap 39 formed between the extending portion and the base curved surface portion 9aa of the hub flange 9a has a shape along the side surface of the hub flange 9a. As a result, on the outboard side of the protective cover 29, intruding muddy water and the like can easily flow outward from the non-contact seal gap 39 along the side surface of the hub flange 9a. The sealing performance at is further improved.

  19 and 20 show still another embodiment of the present invention. In this embodiment of the wheel bearing with sensor, in the embodiment shown in FIGS. 15 and 16, the outer bent portion 29b at the end of the outboard side of the protective cover 29 is arranged outside the inner bent portion 29a as shown in an enlarged sectional view in FIG. It extends further to the outer diameter side than the radial base end. Other configurations are the same as those of the embodiment shown in FIGS. 15 and 16.

  In this way, by extending the outer bent portion 29b at the outboard side end of the protective cover 29 further to the outer diameter side than the outer diameter side base end of the inner bent portion 29a, a portion extending from the outer bent portion 29b to the cylindrical portion 29c. And the radial distance of the non-contact seal gap 39 formed between the base curved surface portion 9aa of the hub flange 9a. Thereby, the sealing performance at the outboard side end of the protective cover 29 is further improved.

  21 and 22 show still another embodiment of the present invention. In this sensor-equipped wheel bearing, as shown in an enlarged cross-sectional view in FIG. 22, the outboard side end of the protective cover 29 protrudes to the outboard side from the outer member 1, and the outer diameter side extends from the outboard side end. An outer bent portion 29d that is bent to the inner bent portion 29d is formed, and then an inner bent portion 29e that is folded back from the tip of the outer bent portion 29d to the inner diameter side and overlaps with the outer bent portion 29d is formed. A cylindrical portion 29f extending toward the curved surface portion 9aa of the base portion of the hub flange 9a of the side member 2 is formed. Thereby, a non-contact seal gap 39 that is narrow and long in the radial direction is formed between the portion extending from the inner bent portion 29e to the tubular portion 29f and the base curved surface portion 9aa of the hub flange 9a. Other configurations are the same as those in the embodiment of FIGS.

  Also in this case, at the end of the protective cover 29 on the outboard side, the non-contact seal gap 39 that is narrow and long in the radial direction is narrow between the inner bent portion 29e to the tube portion 29f and the base curved surface portion 9aa of the hub flange 9a. As a result, the sealing performance at the outboard side end of the protective cover 29 is improved, the sensor failure due to the influence of the external environment can be more reliably prevented, and the load detection can be accurately performed.

  23 and 24 show still another embodiment of the present invention. In this sensor-equipped wheel bearing, in the first embodiment shown in FIGS. 1 to 13, the protective cover 29A provided on the outer peripheral surface of the outer member 1 is configured as follows. In this example, the protective cover 29A is a cylindrical member that covers the outer periphery of the sensor assembly part 31 and the outer member 1 as in the first embodiment, but the outer diameter is directed from the outboard side to the inboard side. The inboard side end is fitted to the outer diameter surface of the flange 1 a of the outer member 1. A lip portion 35A made of an annular elastic body is provided along the opening edge of the protective cover 29A on the outboard side end, and the lip portion 35A is brought into contact with the outer peripheral surface of the outer member 1. Thereby, the space between the outboard side end of the protective cover 29A and the outer peripheral surface of the outer member 1 and the space between the inboard side end of the protective cover 29A and the outer diameter surface of the flange 1a of the outer member 1 are sealed. Intrusion of muddy water, salt water, and the like from the outboard side end into the protective cover 29A can be reliably prevented. As a result, sensor failure due to the influence of the external environment can be reliably prevented, and load detection can be performed accurately.

  As the elastic body constituting the lip portion 35A, a rubber material is desirable. Thereby, the sealing performance at the outboard side end of the protective cover 29A by the lip portion 35A can be ensured. In addition, the lip portion 35A may be integrally formed with the protective cover 29A. Here, as shown in an enlarged cross-sectional view in FIG. 24, the lip portion 35A has a shape that extends with the tip gradually reducing in diameter toward the outboard side. Thereby, infiltration of muddy water, salt water, etc. into the protective cover 29A from the outboard side end can be prevented more reliably. Further, a part of the lip portion 35A is extended to a part of the outer peripheral surface of the protective cover 29A to form a cover outer peripheral surface covering portion 35Aa. As a result, at the end of the outer surface of the protective cover 29A on the outboard side end, a wall formed of the cover outer peripheral surface covering portion 35Aa projects outward, and the lip portion 35A is formed on the outer peripheral surface of the outer member 1 by this wall. It is possible to prevent the muddy water / salt water or the like from flowing into the portion in contact with the water, and to more reliably prevent the muddy water / salt water or the like from entering the protective cover 29A. When attaching the lip portion 35A to the outer peripheral surface of the protective cover 29A, the cover outer peripheral surface covering portion 35Aa is further on the inboard side than the range positioned on the outer peripheral surface of the protective cover 29A in order to obtain the strength necessary for the attachment. It extends to

  The protective cover 29A is formed by, for example, pressing a steel plate having corrosion resistance. Thereby, it can prevent that the protective cover 29A corrodes by an external environment. In addition, the steel cover may be pressed to form the protective cover 29A, and the surface thereof may be subjected to metal plating or painting. Also in this case, the protective cover 29A can be prevented from being corroded by the external environment. In addition, the material of the protective cover 29A may be plastic or rubber.

  Other configurations and effects in this embodiment are the same as those in the first embodiment described with reference to FIGS. In this embodiment and each of the following embodiments, the surface treatment layer 38 described with reference to FIG. 14 may be provided.

  25 and 26 show still another embodiment of the present invention. In this sensor-equipped wheel bearing, in the embodiment shown in FIGS. 23 and 24, the outer peripheral surface of the cover outer peripheral surface covering portion 35Aa of the lip portion 35A provided at the outboard side end of the protective cover 29A is shown in FIG. As shown in the figure, the inclined surface is enlarged in diameter toward the outboard side. Other configurations are the same as those in the embodiment of FIGS.

  In this way, by forming the outer peripheral surface of the cover outer peripheral surface covering portion 35Aa of the lip portion 35A as an inclined surface whose diameter increases toward the outboard side, the lip portion 35A abuts on the outer peripheral surface of the outer member 1. It is possible to prevent the muddy water / salt water or the like from flowing into the portion, and to more reliably prevent the muddy water / salt water etc. from entering the protective cover 29A.

  27 and 28 show still another embodiment of the present invention. In the sensor-equipped wheel bearing, in the embodiment shown in FIGS. 23 and 24, the outboard side end of the protective cover 29A protrudes more toward the outboard side than the outer member 1, and the outboard side end and the rotation side A non-contact seal gap 39A, that is, a labyrinth seal is formed between the inner member 2 and the member. The non-contact seal gap 39A is a narrow gap to the extent that water or the like is prevented from entering when the inner member 2 and the outer member 1 are relatively rotated as described above. Here, as shown in an enlarged cross-sectional view in FIG. 28, the end on the outboard side of the protective cover 29A protrudes to the vicinity of the side facing the inboard side of the hub flange 9a of the inner member 2, and is bent from the tip to the inner diameter side. A bent portion 29Aa directed toward the inboard side is formed, and an inner bent portion 29Ab bent toward the inner diameter side from the tip of the bent portion 29Aa is formed, and a lip portion 35A is provided integrally with the inner bent portion 29Ab. ing. Other configurations are the same as those in the embodiment of FIGS.

  In this way, by forming the non-contact seal gap 39A between the outboard side end of the protective cover 29A and the inner member 2, the seal between the outer member 1 at the outboard side end of the protective cover 29A is formed. However, the contact between the lip portion 35A and the outer peripheral surface of the outer member 1 and the non-contact seal 39A formed between the outboard side end of the protective cover 29A and the hub flange 9a of the inner member 2 are two. Since it is made of a heavy sealed structure, sealing on the outboard side is more reliable, sensor failure due to the influence of the external environment can be more reliably prevented, and load detection can be performed accurately.

  29 and 30 show still another embodiment of the present invention. In the wheel bearing with sensor, in the embodiment shown in FIGS. 23 and 24, the bent portion 29Aa at the end of the outboard side of the protective cover 29A is contracted toward the inboard side as shown in the enlarged sectional view of FIG. The shape is inclined in diameter. Other configurations are the same as those of the embodiment shown in FIGS.

  In this way, the bent portion 29Aa at the end of the outboard side of the protective cover 29A is formed so as to incline toward the inboard side, thereby entering the outboard side end of the outer member 1 from the non-contact seal gap 39A. The muddy water, salt water, and the like that has been discharged can be easily discharged outward from the non-contact seal gap 39A along the inclined surface of the bent portion 29Aa, and the sealing performance at the end of the protective cover 29A on the outboard side is further improved.

31 and 32 show still another embodiment of the present invention. In this embodiment of the wheel bearing with sensor, in the embodiment shown in FIGS. 23 and 24, an O-ring 35 </ b> B as a seal member is provided between the small-diameter cylindrical portion 29 s on the outboard side end of the protective cover 29 </ b> A and the outer periphery of the outer member 1. Is interposed. As shown in an enlarged cross-sectional view in FIG. 32, the O-ring 35B is fitted and attached in an annular seal mounting groove provided on the outer peripheral surface of the outer member 1. Other configurations are the same as those of the embodiment shown in FIGS.
As described above, even when the O-ring 35B is provided as a seal member, it is possible to reliably prevent the intrusion of muddy water, salt water, etc. into the protective cover 29A from the outboard side end of the protective cover 29A. Failure can be reliably prevented and load detection can be performed accurately.

  33 and 34 show still another embodiment of the present invention. In the sensor-equipped wheel bearing, in the embodiment shown in FIGS. 23 and 24, the lip portion 35A provided at the outboard side end of the protective cover 29A is brought into contact with the surface of the inner member 2 that is the rotation side member. ing. Specifically, as shown in an enlarged cross-sectional view in FIG. 34, the end of the protective cover 29A on the outboard side protrudes from the outer member 1 to the outboard side, and the hub wheel 9 that is a component of the inner member 2 is formed. The lip portion 35A is brought into contact with the side surface of the hub flange 9a facing the inboard side. Other configurations are the same as those of the embodiment shown in FIGS.

  As described above, even when the lip portion 35A provided on the outboard side end of the protective cover 29A is brought into contact with the hub flange 9a of the inner member 2, the outboard side end of the protective cover 29A enters the protective cover 29A. Intrusion of muddy water, salt water, and the like can be reliably prevented, so that sensor failure due to the influence of the external environment can be reliably prevented, and load detection can be accurately performed. In this case, since the outboard side end of the bearing space formed between the outer member 1 and the inner member 2 is also sealed, the outboard side seal 7 can be omitted. It is.

FIG. 35 is a cross-sectional view showing an outline of an in-wheel motor-equipped wheel bearing device equipped with the sensor-equipped wheel bearing A according to the first embodiment shown in FIGS. 1 to 13. This in-wheel type motor-integrated wheel bearing device includes a sensor-equipped wheel bearing A that rotatably supports a hub of the drive wheel 40, an electric motor B as a rotational drive source, and a speed reduction of the rotation of the electric motor B. Thus, the speed reducer C that transmits to the hub and the brake D that applies braking force to the hub are arranged on the central axis of the drive wheels 40. The electric motor B is a radial gap type in which a radial gap is provided between a stator 42 fixed to a cylindrical casing 41 and a rotor 44 attached to an output shaft 43. The reduction gear C is configured as a cycloid reduction gear.
In addition, in FIG. 35, although the example which mounts the wheel bearing A with a sensor of embodiment shown in FIGS. 1-13 was shown, not only this but the wheel bearing with sensor of other embodiment of this invention is shown. Similar effects can be achieved when used.

  Thus, when the sensor-equipped wheel bearing A according to any one of the configurations of the present invention is used as a wheel bearing of a wheel bearing device with a built-in in-wheel motor, sensor failure due to the influence of the external environment is prevented. Thus, an in-wheel motor-equipped wheel bearing device that can accurately detect the load acting on the wheel bearing and the tire ground contact surface over a long period of time can be obtained.

  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 relates to a first or second generation type wheel bearing in which the bearing portion and the hub are independent parts. Further, the present invention can be applied to a fourth generation type wheel bearing in which a part of the inner member is constituted by an outer ring of a constant velocity joint, and can also be applied to a tapered roller type wheel bearing of each generation type. Further, the present invention can also be applied to a wheel bearing in which the outer member is a rotation side member. In that case, a sensor unit is provided on the outer periphery of the inner member.

DESCRIPTION OF SYMBOLS 1 ... Outer member 1a ... Body mounting flange 2 ... Inner members 3, 4 ... Rolling surface 5 ... Rolling element 20 ... Load detecting sensor part 21 ... Strain generating member 21a ... Contact fixing part 21b ... Notch part 21d ... Bent part 22, 22A, 22B ... Strain sensor 29, 29A ... Protective cover 31 ... Sensor assembly 32 ... Estimating means 35, 35A ... Lip part <seal member>
35B ... O-ring (seal member)
38 ... Surface treatment layers 39, 39A ... Non-contact seal gap

Claims (37)

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,
A strain generating member having two or more contact fixing portions fixed to the fixed side member of the outer member and the inner member in contact with the fixed side member, and attached to the strain generating member. A sensor-equipped wheel bearing provided with a sensor assembly in which a plurality of load detection sensor portions including two or more sensors for detecting strain of a strain generating member are provided,
Estimating means for estimating a load acting on the wheel bearing is provided based on output signals of the two or more sensors,
The strain generating members of the plurality of load detecting sensor portions are used as one belt-like strain generating member continuous over the plurality of load detecting sensor portions, and the two or more contact fixings in the belt-shaped strain generating members are performed. The parts are arranged so as to be at the same axial position on the outer diameter surface of the fixed side member and at positions separated from each other in the circumferential direction,
A plurality of load detection sensors are covered with a cylindrical protective cover that surrounds the outer periphery of the fixed member, and is fitted to the outer periphery of the fixed member at one end in the axial direction of the protective cover. Provided with an annular sealing member made of an elastic body, and this sealing member was brought into contact with the surface of the stationary member, or the surface of the rotating member of the outer member and the inner member,
The wheel bearing with a sensor characterized by the above-mentioned.   2. The sensor-equipped wheel according to claim 1, wherein the one belt-like strain generating member is bent between adjacent load detection sensor portions at a plurality of locations in the longitudinal direction and fixed to the stationary member with a fixture. Bearings.   3. The fixed side member according to claim 1, wherein the fixed side member has a flange for attachment to a vehicle body on an outer periphery, and the shape of the fixed side member viewed from the front side in the bearing axial direction is orthogonal to the bearing axis. A sensor-equipped wheel bearing having a shape that is line-symmetric with respect to a line segment or a shape that is point-symmetric about a bearing axis.   4. The sensor according to claim 1, wherein a surface treatment having corrosion resistance or corrosion resistance is applied to at least a contact portion of the outer diameter surface of the fixed side member with the plurality of load detection sensor portions. Wheel bearing.   The wheel bearing with sensor according to claim 4, wherein the surface treatment is metal plating, painting, or coating.   The sensor-equipped wheel bearing according to any one of claims 1 to 5, wherein the stationary member is an outer member, and the rotating member is the inner member.   7. The method according to claim 1, wherein an outboard side end of the protective cover is fitted to an outer peripheral surface of a fixed side member, and the annular shape is formed along an opening edge of the inboard side end of the protective cover. A sensor-equipped wheel bearing in which a lip portion made of an elastic body is provided, and the lip portion is brought into contact with a side surface facing the outboard side of a flange provided on the fixed side member or an outer peripheral surface of the fixed side member.   8. The inboard side end portion of the protective cover according to claim 7, wherein a hole portion from which the lead portion of the signal cable is drawn out from the protective cover is provided, and a sealing material is provided in a portion where the signal cable lead portion is drawn out from the hole portion. Coated wheel bearing with sensor.   In Claim 7 or Claim 8, the outboard side end of the protective cover is projected to the outboard side from the fixed side member, and a non-contact seal gap is formed between the outboard side end and the rotating side member. Formed wheel bearing with sensor.   The sensor-equipped wheel bearing according to claim 9, wherein an outboard side end of the protective cover has a shape along the rotation side member.   7. The protective cover according to claim 1, wherein an inboard side end of the protective cover is fitted to an outer diameter surface of a flange for mounting on a vehicle body provided on the fixed side member. A lip portion made of the annular elastic body is provided along an opening edge of the outboard side end of the outer board, and the lip portion is an outer peripheral surface of the fixed side member or a rotation side member of the outer member and the inner member. Wheel bearing with sensor in contact with the surface.   The sensor-equipped wheel bearing according to claim 11, wherein the lip portion has a shape in which a tip is gradually reduced in diameter toward the outboard side, and the lip portion is brought into contact with an outer peripheral surface of the fixed side member.   The sensor-equipped wheel bearing according to claim 11 or 12, wherein a part of the lip portion is extended to a part of the outer peripheral surface of the protective cover to form a cover outer peripheral surface covering portion.   The sensor-equipped wheel bearing according to claim 13, wherein the outer peripheral surface of the cover outer peripheral surface covering portion of the lip portion is an inclined surface whose diameter increases toward the outboard side.   15. The outboard side end of the protective cover is protruded more to the outboard side than the fixed side member according to claim 11, and between the outboard side end and the rotating side member. Bearing for sensor wheel with non-contact seal gap.   12. The sensor-equipped wheel bearing according to claim 11, wherein the rotation side member has a hub flange for wheel attachment, and the lip portion is brought into contact with a side surface of the hub flange facing the inboard side.   17. The load detection sensor unit, a signal processing IC that processes an output signal of the load detection sensor unit, and the processed output signal to the outside of the bearing according to claim 7. A sensor assembly formed by connecting electronic components including a signal cable to be taken out in a ring shape is attached to the outer peripheral surface of the fixed side member concentrically with the fixed side member, and the sensor assembly is covered with the protective cover. Wheel bearing.   The wheel bearing with sensor according to any one of claims 7 to 18, wherein the protective cover is a molded product obtained by pressing a steel plate having corrosion resistance.   19. The sensor-equipped wheel bearing according to any one of claims 7 to 18, wherein the protective cover is obtained by pressing a steel plate having corrosion resistance and performing metal plating or coating treatment on a surface thereof.   The sensor-equipped wheel bearing according to any one of claims 6 to 19, wherein the lip portion is integrally formed with the protective cover.   The sensor-equipped wheel bearing according to claim 20, wherein the elastic body constituting the lip portion is made of a rubber material.   22. The sensor-equipped device according to claim 1, wherein the estimation unit calculates an amplitude of an output signal or a value corresponding to the amplitude from a difference between output signals of the two or more sensors. Wheel bearing.   23. The sensor-equipped wheel bearing according to claim 22, wherein the estimating means generates an absolute value of the signal from the difference between the output signals, and uses the peak value or the direct current component as a value corresponding to the amplitude of the output signal.   23. The wheel bearing with sensor according to claim 22, wherein the estimating means calculates an effective value of the signal from the difference between the output signals and sets the value as a value corresponding to the amplitude of the output signal.   In Claim 22, the said estimation means calculates | requires the maximum value and minimum value in the time interval more than one period of the vibration period from the difference of an output signal, and makes the value the amplitude equivalent value of an output signal. Wheel bearing with sensor.   26. The distance between two contact fixing portions located at both ends of a circumferential arrangement of outer diameter surfaces of the fixed side member among the two or more contact fixing portions according to any one of claims 1 to 25. Is a sensor-equipped wheel bearing with the same arrangement pitch as the rolling elements.   The distance between the adjacent sensors in the two or more sensors in the circumferential direction of the outer diameter surface of the fixed side member in the circumferential direction of the rolling element according to any one of claims 1 to 12 is { Sensor-equipped wheel bearing with 1/2 + n (n: integer)} times or a value approximated to these values.   28. The load detection sensor unit according to claim 1, wherein the load detection sensor unit includes three contact fixing units and two sensors, and between and adjacent to the adjacent first and second contact fixing units. A sensor-equipped wheel bearing in which each sensor is mounted between the matching second and third contact fixing portions.   In Claim 28, the space | interval about the circumferential direction of the outer diameter surface of the said fixed side member of an adjacent contact fixing | fixed part or an adjacent sensor is {1/2 + n (n: integer)} times the arrangement pitch of rolling elements, or Sensor-equipped wheel bearing with values approximate to these values.   30. The sensor according to any one of claims 1 to 29, wherein the strain generating member is formed of a thin plate having a strip shape with a uniform planar plane shape or a strip shape with a planar plan shape having a notch portion on a side side. Wheel bearing.   The upper surface portion, the lower surface portion, and the lower surface portion of the outer diameter surface of the fixed side member, wherein the load detection sensor portion is in a vertical position and a horizontal position with respect to a tire ground contact surface. Sensor-equipped wheel bearings arranged on the right and left surfaces.   18. The sensor-equipped wheel bearing according to claim 1, wherein the estimation means further estimates a load acting on the wheel bearing using a sum of output signals of the two or more sensors. . In any one of Claims 1 thru | or 28, the contact fixing | fixed part of the said distortion generation member in the said sensor part for load detection is three,
The three contact fixing portions of the belt-shaped strain generating member are arranged so as to be in the same axial direction position on the outer diameter surface of the fixed side member and spaced apart from each other in the circumferential direction, and the adjacent contact fixing portions. The interval in the circumferential direction of the outer diameter surface of the fixed side member of the sensor adjacent to each other or the adjacent sensor is {1/2 + n (n: integer)} times the arrangement pitch of the rolling elements or approximate to these values The sensor-equipped wheel bearing is configured to estimate a load acting on the wheel bearing based on a difference between output signals of the two sensors.   34. The sensor-equipped wheel bearing according to claim 1, wherein the seal member fitted to the outer periphery of the stationary member at one end of the protective cover is a lip portion.   34. The sensor-equipped wheel bearing according to any one of claims 1 to 33, wherein the seal member fitted to the outer periphery of the stationary member at one end of the protective cover is an O-ring.   36. A method of assembling a sensor-equipped wheel bearing according to any one of claims 1 to 35, wherein the stationary member is a single member or the rolling member is assembled to the stationary member. The belt-shaped strain generating member constituting a plurality of load detection sensor portions is attached to the outer peripheral surface of the fixed side member, the bearing is assembled after the protective cover is press-fitted into the outer peripheral surface of the fixed side member. Assembly method for wheel bearing with sensor.   36. An in-wheel type motor-integrated wheel bearing device comprising the sensor-equipped wheel bearing according to any one of claims 1 to 35.

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