JP2009128265A - Wheel bearing with sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wheel bearing with a sensor which avoids concentration of a strain on a corner portion of a notch part of a strain generating member in a sensor unit and thus enables accurate detection of a load on a wheel. <P>SOLUTION: The wheel bearing is constituted by interposing rolling elements between opposite rolling surfaces in a plurality of rows of exterior and interior members. One or more sensor units 20 are provided on a fixed-side one out of the exterior and interior members. The sensor unit 20 consists of: the strain generating member 21 which includes two or more contacting fixed parts fixed in contact with the fixed-side member; and the sensor 22 which is attached to the strain generating member 21, and detects a strain of the strain generating member 21. The member 21 includes the notch parts 21b located between the contacting fixed parts, and the corner portions of the notch parts 21b have circular-arc-shaped sections. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

As a technique for detecting a load applied to each wheel of an automobile, a sensor unit including a strain generating member and a strain sensor attached to the strain generating member is attached to a fixed ring of a bearing, and the strain generating member is attached to the fixed wheel. A sensor-equipped wheel bearing has been proposed which has at least two contact fixing portions, and has at least one notch portion between adjacent contact fixing portions, and the strain sensor is disposed in the notch portion. (For example, Patent Document 1).
According to this sensor-equipped wheel bearing, when a load is applied to the rotating wheel as the vehicle travels, the fixed wheel is deformed via the rolling elements, and this deformation causes distortion of the sensor unit. The strain sensor provided in the sensor unit detects the strain of the sensor unit. If the relationship between strain and load is obtained in advance through experiments and simulations, the load applied to the wheel can be detected from the output of the strain sensor.
JP 2007-057299 A

  When a strain generating member having a notch portion is fixed to a fixed ring of the bearing as in the sensor-equipped wheel bearing with the above configuration, the strain concentrates on the corner portion of the notch portion. For this reason, even if the amount of strain that causes plastic deformation is not reached at the mounting portion of the strain sensor that is the detection portion, plastic deformation may occur at the corner of the notch. When such plastic deformation occurs, there is a problem that the deformation at the fixed ring of the bearing is not accurately transmitted to the sensor unit and accurate strain measurement cannot be performed. In addition, since strain concentrates at the corner of the notch, there is a problem in that the strain distribution in the detection unit varies and positioning of the strain sensor greatly affects the measurement result.

  An object of the present invention is to provide a sensor-equipped wheel bearing that can accurately detect a load applied to a wheel while avoiding the concentration of distortion at a corner portion of a notch portion of a strain generating member in a sensor unit.

The sensor-equipped wheel bearing according to the present invention includes an outer member having a double-row rolling surface formed on the inner periphery, an inner member having a rolling surface opposed to the rolling surface formed on the outer periphery, A wheel bearing comprising a double row rolling element interposed between opposing rolling surfaces of the member and rotatably supporting the wheel with respect to the vehicle body, wherein the fixed side member of the outer member and the inner member One or more sensor units comprising a strain generating member having two or more contact fixing portions fixed in contact with the sensor, and a sensor attached to the strain generating member and detecting the strain of the strain generating member, The strain generating member has a notch portion between the contact fixing portions, and a corner portion of the notch portion has an arcuate cross section.
When a load acts between the tire of the wheel and the road surface, the load is also applied to the fixed side member (for example, the outer member) of the wheel bearing, causing deformation. Since the two contact fixing portions of the strain generating member having the notch portion in the sensor unit are fixed in contact with the outer member, the strain of the outer member is enlarged and transmitted to the strain generating member. Detected and the load can be estimated from the output signal. In particular, since the corner of the notch has an arcuate cross section, strain is not concentrated on the corner of the notch, and the possibility of plastic deformation is reduced. In addition, since strain does not concentrate at the corners of the notch, variation in the strain distribution at the detection part of the strain generating member, that is, the sensor mounting part is reduced, and the influence of the sensor mounting position on the sensor output signal. Becomes smaller. Thereby, a load can be estimated accurately.

In the present invention, the strain generating member may be made of a thin plate material having a strip shape in a plane and having a notch portion on a side portion.
When the strain generating member is a thin plate material, the strain of the fixed member is easily transmitted to the strain generating member in an enlarged manner, and the strain is detected with high sensitivity by the sensor, so that the load can be estimated with high accuracy. In addition, when the strain generating member is formed of a thin plate material having a strip-like outline and having a notch on the side portion, the shape of the strain generating member becomes simple and excellent in mass productivity.

  In the present invention, the sensor unit has an outer diameter surface of the fixed side member such that the two contact fixing portions of the strain generating member are positioned in the same axial direction of the fixed side member and spaced apart from each other in the circumferential direction. May be arranged. In the case of this configuration, the strain in the circumferential direction of the fixed side member can be detected by the sensor unit. That is, since the load acting between the tire and the road surface is transmitted from the rotation side member to the fixed side member via the rolling elements, the outer diameter surface of the fixed side member is distorted in the circumferential direction, and the contact fixing described above. The detection sensitivity is improved by the arrangement of the portions, and the load can be estimated with higher accuracy.

  In the present invention, the sensor unit has an outer diameter surface of the fixed side member such that the two contact fixing portions of the strain generating member are located at the same circumferential position of the fixed side member and spaced apart from each other in the axial direction. May be arranged.

  In the present invention, a flange for mounting a vehicle body to be attached to a knuckle is provided on the outer periphery of the fixed side member, bolt holes are provided at a plurality of circumferential directions of the flange, and the flange has a circumference provided with each bolt hole. The direction portion is a projecting piece that protrudes to the outer diameter side than the other portion, and the two contact fixing portions of the strain generating member are on the outer diameter surface of the fixed side member that is the center between the adjacent projecting pieces. It may be arranged. In the case of this configuration, the strain generating member is disposed at a position away from the projecting piece causing the hysteresis, and the hysteresis generated in the output signal of the sensor is reduced accordingly, and the load can be estimated with higher accuracy.

  In the present invention, the sensor unit is arranged such that the two contact fixing portions of the strain generating member are located at the same axial direction position of the fixed side member and spaced apart from each other in the circumferential direction. The interval between the fixed portions may be ½ or less of the interval between the adjacent protruding pieces. In the case of this configuration, the effect of slipping around the knuckle bolt that causes hysteresis can be reduced, and the hysteresis generated in the output signal of the sensor is reduced accordingly, and the load can be estimated more accurately.

  In the present invention, the sensor unit may be disposed at an axial position around the outboard rolling surface of the double row rolling surfaces. In this configuration, since the ground contact space is relatively large and the tire acting force is transmitted to the stationary member via the rolling elements, the sensor unit is disposed at a relatively large amount of deformation, thereby improving detection sensitivity. Thus, the load can be estimated with higher accuracy.

  In this invention, the strain generating member of the sensor unit is not plastically deformed even in a state where the assumed maximum force is applied as an external force acting on the stationary member or an acting force acting between the tire and the road surface. It is good as a thing. If plastic deformation occurs before the assumed maximum force is applied, the deformation of the fixed-side member is not accurately transmitted to the sensor unit and affects the strain measurement. It is desirable that plastic deformation does not occur even in a state where is applied.

  In this invention, the contact fixing portion of the strain generating member may be fixed to the outer diameter surface of the fixing side member via a spacer. In this configuration, even if the strain generating member is a thin plate, the two contact fixing portions can be kept in a non-contact state with respect to the fixed side member, and the distortion of the fixed side member is effective for the strain generating member. Can communicate.

  In this invention, you may provide a groove | channel between the fixed positions of the two contact fixing | fixed parts of the said sensor unit in the outer-diameter surface of the said fixed side member. Even in this configuration, even if the strain generating member is a thin plate, the two contact fixing portions can be kept in a non-contact state with respect to the fixed side member, and the distortion of the fixed side member is effective for the generating member. Can communicate.

  In the present invention, the stationary member may be provided with at least one or more sensor unit pairs, each of which includes two of the sensor units arranged at a position forming a phase difference of 180 degrees in the circumferential direction. . In the case of this configuration, when a load in a certain direction increases, a portion where the rolling element and the rolling surface are in contact with each other and a portion which is not in contact appear with a 180-degree phase difference. If it is installed with a phase difference, the load applied to the fixed member is always transmitted to one of the sensor units via the rolling elements, and the load can be detected by the sensor. Therefore, the load can be accurately estimated under any load condition.

  In this invention, two pairs of the sensor unit pairs are provided, and the two sensor units of the pair of sensor units are an upper surface portion and a lower surface portion of the outer diameter surface of the fixed side member that are located above the tire ground contact surface. The two sensor units of the other pair of sensor units may be arranged on the right surface portion and the left surface portion of the outer diameter surface of the fixed side member that is in the front-rear position with respect to the tire ground contact surface. . In the case of this configuration, the load applied in the vertical direction and the load serving as the driving force can be accurately detected under any load condition.

In this invention, you may provide the estimation means which estimates a load by at least any one among the absolute value of the output signal of the said sensor, the average value of the said output signal, and the amplitude of the said output signal.
During the rotation of the wheel bearing, there may be a periodic change in the amplitude of the output signal of the sensor of the sensor unit depending on the presence or absence of rolling elements passing through the vicinity of the sensor unit on the rolling surface. Therefore, by measuring the period of the amplitude in the output signal by the estimating means, it is possible to detect the passing speed of the rolling element, that is, the rotational speed of the wheel. As described above, when the output signal varies, the load can be calculated from the average value or amplitude of the output signal. If no change is observed, the load can be calculated from the absolute value.

  The sensor-equipped wheel bearing according to the present invention includes an outer member having a double-row rolling surface formed on the inner periphery, an inner member having a rolling surface opposed to the rolling surface formed on the outer periphery, A wheel bearing comprising a double row rolling element interposed between opposing rolling surfaces of the member and rotatably supporting the wheel with respect to the vehicle body, wherein the fixed side member of the outer member and the inner member One or more sensor units comprising a strain generating member having two or more contact fixing portions fixed in contact with the sensor, and a sensor attached to the strain generating member and detecting the strain of the strain generating member, Since the strain generating member has a notch portion between the contact fixing portions and the corner portion of the notch portion has an arcuate cross section, the strain concentrates on the corner portion of the notch portion of the strain generating member in the sensor unit. To accurately detect the load on the wheels Door can be.

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

  As shown in the sectional view of FIG. 1, the bearing for this sensor-equipped wheel bearing includes an outer member 1 in which a double row rolling surface 3 is formed on the inner periphery, and rolling facing each of these rolling surfaces 3. The inner member 2 has a surface 4 formed on the outer periphery, and the outer member 1 and the double row rolling elements 5 interposed between the rolling surfaces 3 and 4 of the inner member 2. This wheel bearing is a double-row angular ball bearing type, and the rolling elements 5 are made of balls and are held by a cage 6 for each row. The rolling surfaces 3 and 4 have an arc shape in cross section, and are formed so that the ball contact angle is aligned with the back surface. Both ends of the bearing space between the outer member 1 and the inner member 2 are sealed by a pair of seals 7 and 8, respectively.

The outer member 1 is a fixed side member, and has a vehicle body mounting flange 1a attached to a knuckle 16 in a suspension device (not shown) of the vehicle body on the outer periphery, and the whole is an integral part. The flange 1a is provided with bolt holes 14 for attaching a knuckle at a plurality of locations in the circumferential direction, and a knuckle bolt 18 inserted into the bolt insertion hole 17 of the knuckle 16 from the inboard side is screwed into the bolt hole 14. The vehicle body mounting flange 1 a is attached to the knuckle 16.
The inner member 2 is a rotating side member, and includes a hub wheel 9 having a hub flange 9a for wheel mounting, and an inner ring 10 fitted to the outer periphery of the end portion on the inboard side of the shaft portion 9b of the hub wheel 9. And become. The hub wheel 9 and the inner ring 10 are formed with the rolling surfaces 4 of the respective rows. An inner ring fitting surface 12 having a small diameter with a step is provided on the outer periphery of the inboard side end of the hub wheel 9, and the inner ring 10 is fitted to the inner ring fitting surface 12. A through hole 11 is provided at the center of the hub wheel 9. The hub flange 9a is provided with press-fitting holes 15 for hub bolts (not shown) at a plurality of locations in the circumferential direction. In the vicinity of the base portion of the hub flange 9a of the hub wheel 9, a cylindrical pilot portion 13 for guiding a wheel and a braking component (not shown) protrudes toward the outboard side.

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

  A pair of sensor units 19 each including two sensor units 20 is provided on the outer diameter surface of the outer member 1 that is a fixed member. These two sensor units 20 are arranged at positions that form a phase difference of 180 degrees in the circumferential direction of the outer diameter surface of the outer member 1. One or more pairs of sensor units 19 may be provided. Here, the two sensor units 20 constituting the sensor unit pair 19 are provided at two positions on the outer diameter surface of the outer member 1 that is located above the tire ground contact surface, that is, the upper surface portion and the lower surface portion. The vertical load Fz or the axial load Fy acting on the bearing or the tire is detected. Specifically, as shown in FIG. 2, one sensor unit 20 is arranged at the center between two adjacent projecting pieces 1 aa on the upper surface portion of the outer diameter surface of the outer member 1, and the outer member 1. Another one sensor unit 20 is arranged at the center portion between two adjacent projecting pieces 1aa on the lower surface portion of the outer diameter surface.

  As shown in FIGS. 3 and 4 in an enlarged plan view and an enlarged cross-sectional view, these sensor units 20 are a strain generating member 21 and a sensor that is attached to the strain generating member 21 and detects the strain of the strain generating member 21. 22 The strain generating member 21 is made of an elastically deformable metal such as steel, and is made of a thin plate material of 3 mm or less. The corner of the notch 21b has an arcuate cross section. Further, the strain generating member 21 has two contact fixing portions 21 a that are fixed to the outer diameter surface of the outer member 1 through spacers 23 at both ends. Note that, depending on the shape of the strain generating member 21, two or more contact fixing portions 21a may be provided. The sensor 22 is affixed to a location where the strain increases with respect to the load in each direction on the strain generating member 21. Here, as the location, the central portion sandwiched between the notch portions 21b on both sides on the outer surface side of the strain generating member 21 is selected, and the sensor 22 detects the strain in the circumferential direction around the notch portion 21b. . 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 the plastic deformation occurs, the deformation of the outer member 1 is not transmitted to the sensor unit 20 and affects the measurement of strain. The assumed maximum force is, for example, the maximum force in a range where the wheel bearing is not damaged by the application of the force.

  In the sensor unit 20, the two contact fixing portions 21a of the strain generating member 21 are located at the same dimension in the axial direction of the outer member 1, and the two contact fixing portions 21a are separated from each other in the circumferential direction. These contact fixing portions 21a are fixed to the outer diameter surface of the outer member 1 by bolts 24 via spacers 23, respectively. In this case, the interval Ls between the two contact fixing portions 21a is set to be ½ or less of the interval Lb between the adjacent projecting pieces 1aa in the vehicle body mounting flange 1a of the outer member 1. Each of the bolts 24 is inserted into a bolt insertion hole 26 of the spacer 23 from a bolt insertion hole 25 provided in the contact fixing portion 21a in the radial direction, and a bolt hole 27 provided in the outer peripheral portion of the outer member 1. Screwed on. In this way, by fixing the contact fixing portion 21a to the outer diameter surface of the outer member 1 via the spacer 23, the central portion having the notch portion 21b in the strain generating member 21 having a thin plate shape is the outer member 1. It becomes a state away from the outer diameter surface of this, and distortion deformation around the notch 21b becomes easy. As the axial position where the contact fixing portion 21a is disposed, an axial position that is the periphery of the rolling surface 3 of the outboard side row of the outer member 1 is selected here. Here, the periphery of the rolling surface 3 of the outboard side row is a range from the intermediate position of the rolling surface 3 of the inboard side row and the outboard side row to the formation portion of the rolling surface 3 of the outboard side row. It is. In order to stably fix the sensor unit 20 to the outer diameter surface of the outer member 1, a flat portion 1 b is formed at a location where the spacer 23 is contacted and fixed on the outer diameter surface of the outer member 1.

  In addition, as shown in a cross-sectional view in FIG. 5, grooves 1 c are provided at two intermediate portions where the two contact fixing portions 21 a of the strain generating member 21 are fixed on the outer diameter surface of the outer member 1. The spacer 23 may be omitted, and the intermediate portion of the two contact fixing portions 21 a where the notch portions 21 b of the strain generating member 21 are located may be separated from the outer diameter surface of the outer member 1.

  Various sensors can be used as the sensor 22. For example, the 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 sensor 22 can also be formed on the strain generating member 21 with a thick film resistor.

  The sensor 22 of the sensor unit 20 is connected to the estimation means 30. Here, the estimating means 30 is means for estimating the acting force between the wheel tire and the road surface from the output signal of the sensor 22, and includes a signal processing circuit, a correction circuit, and the like. The estimation means 30 has relationship setting means (not shown) in which the relationship between the acting force between the wheel tire and the road surface and the output signal of the sensor 22 is set by an arithmetic expression or a table or the like. The acting force is output from the output signal using the relationship setting means. The setting contents of the relationship setting means are obtained by a test or simulation in advance.

  When a load acts between the tire of the wheel and the road surface, the load is also applied to the outer member 1 that is a stationary member of the wheel bearing, causing deformation. Since the two contact fixing portions 21a of the strain generating member 21 having the notch portion 21b in the sensor unit 20 are fixed in contact with the outer member 1, the strain of the outer member 1 is enlarged and transmitted to the strain generating member 21. The distortion is detected by the sensor 22, and the load can be estimated from the output signal. In this case, since the corner of the notch 21b has an arcuate cross section, strain does not concentrate on the corner of the notch 21b, and the possibility of plastic deformation is reduced. In addition, since the strain is not concentrated at the corner of the notch 21 b, variation in the strain distribution at the detection portion of the strain generation member 21, that is, the mounting portion of the sensor 22 is reduced, and the mounting position of the sensor 22 is The effect on the output signal is also reduced. Thereby, a load can be estimated accurately.

In the above description, the case where the acting force between the wheel tire and the road surface is detected is shown. However, not only the acting force between the wheel tire and the road surface but also the force acting on the wheel bearing (for example, the preload amount) is detected. It is also good.
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.

  In the case of this embodiment, the strain generating member 21 of the sensor unit 20 is formed of a thin plate material having a strip-like shape in plan and having a notch portion on the side portion. The distortion is easily detected by the sensor 22, the hysteresis generated in the output signal is reduced, and the load can be estimated with high accuracy. Further, the shape of the strain generating member 21 becomes simple, and the mass productivity is excellent.

  Further, in this embodiment, in the installation of the sensor unit 20 on the outer diameter surface of the outer member 1 that is a stationary member, the two contact fixing portions 21a of the distortion generating member 21 are connected to the same axis of the outer member 1. Since they are arranged so as to be in the directional position and spaced apart from each other in the circumferential direction, the circumferential distortion of the outer member 1 can be detected by the sensor unit 20. In the case of this embodiment, the load acting between the tire and the road surface is transmitted from the inner member 2 which is a rotation side member to the outer member 1 via the rolling elements 5, so that the outer diameter surface of the outer member 1 Is distorted in the circumferential direction, and the detection sensitivity is improved by the arrangement of the contact fixing portion 21a described above, and the load can be estimated with higher accuracy.

  Moreover, in this embodiment, the circumferential direction part in which the bolt hole 14 for knuckle attachment was provided in multiple places of the circumferential direction of the vehicle body attachment flange 1a of the outer member 1 which is a fixed side member is outside the other part. Although the projecting piece 1aa protrudes to the radial side, the two contact fixing portions 21a of the strain generating member 21 in the sensor unit 20 are arranged at the center between the adjacent projecting pieces 1aa, which causes the hysteresis. The strain generating member 21 is arranged at a position away from the protruding piece 1aa, and the hysteresis generated in the output signal of the sensor 22 is reduced accordingly, and the load can be estimated more accurately.

  Further, since the distance Ls between the two contact fixing portions 21a is set to be ½ or less of the distance Lb between the adjacent projecting pieces 1aa, the influence of the slip around the knuckle bolt 18 (FIG. 1) that causes hysteresis. Thus, the hysteresis generated in the output signal of the sensor 22 is reduced accordingly, and the load can be estimated more accurately.

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

  Moreover, in this embodiment, the sensor which makes two sets of the sensor units 20 arrange | positioned in the position which makes the 180 degree phase difference in the circumferential direction on the outer diameter surface of the outer member 1 which is a stationary member. Since at least one unit pair 19 is provided, the load can be accurately estimated under any load condition. That is, when a load in a certain direction increases, a portion where the rolling element 5 and the rolling 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 installed with a phase difference, the load applied to the outer member 1 is always transmitted to one of the sensor units 20 via the rolling elements 5, and the load can be detected by the sensor 22.

  Further, during the rotation of the wheel bearing, depending on the presence or absence of the rolling element 5 passing through the vicinity of the sensor unit 20 on the rolling surface 3, the waveform shown in FIG. Periodic changes may occur as shown. This is because the amount of deformation differs between when the rolling element 5 passes and when it does not pass, and the amplitude of the output signal of the sensor 22 has a peak value for each passing period of the rolling element 5. Therefore, by measuring the period of this peak value in the detection signal by, for example, the estimation means 30, it is possible to detect the passing speed of the rolling element 5, that is, the rotational speed of the wheel. As described above, when the output signal varies, the estimation unit 30 can estimate the load from the average value or amplitude of the output signal of the sensor 22 of the sensor unit 20. If no change is observed, the load can be calculated from the absolute value.

In this embodiment, the following configuration is not particularly limited.
・ Number of sensor units 20 installed, installation location, number of contact fixing parts 21a, sensors 22, and notches 21b ・ Shape of sensor unit 20, fixing method (adhesion, welding, etc.), fixing direction (axial distortion) May be detected)

7 to 9 show another embodiment of the present invention. In the sensor-equipped wheel bearing, in the embodiment shown in FIGS. 1 to 6, the two sensor units 20 of the sensor unit pair 19 are configured as follows. Also in this case, the sensor unit 20 includes a strain generating member 21 and a sensor 22 that is attached to the strain generating member 21 and detects the strain of the strain generating member 21, as shown in an enlarged cross-sectional view in FIG. The strain generating member 21 has two contact fixing portions 21a projecting on the inner surface facing the outer diameter surface of the outer member 1 at both ends, and these contact fixing portions 21a are formed on the outer diameter surface of the outer member 1. Fixed in contact. Of the two contact fixing portions 21a, one contact fixing portion 21a is disposed at an axial position around the rolling surface 3 of the outboard side row of the outer member 1, and is located on the outboard side from this position. Another contact fixing portion 21a is arranged at the position, and both the contact fixing portions 21a are arranged at the same phase position in the circumferential direction of the outer member 1. That is, the sensor unit 20 is arranged so that the two contact fixing portions 21a of the distortion generating member 21 are located at the same circumferential direction position of the outer member 1 that is the fixed side member and at positions separated from each other in the axial direction. The outer member 1 is arranged on the outer diameter surface. 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. Also in this case, in order to stably fix the sensor unit 20 to the outer diameter surface of the outer member 1, the contact fixing portion 21 a of the strain generating member 21 on the outer diameter surface of the outer member 1 is fixed at a location where the sensor unit 20 is fixed. It is desirable to form a flat part.
In addition, one notch portion 21 b that opens to the inner surface side is formed in the central portion of the strain generating member 21. Also in this case, the corner portion of the notch portion 21b has an arcuate cross section so that distortion is not concentrated on the corner portion of the notch portion 21b. The sensor 22 is affixed to a location where the strain increases with respect to the load in each direction on the strain generating member 21. Here, as the location, the position around the notch 21b, specifically, the position on the outer surface side of the strain generating member 21 and the back side of the notch 21b is selected, and the sensor 22 has the notch 21b. Detect peripheral distortion.

  The two contact fixing portions 21 a of the strain generating member 21 are fixed by being fastened to the outer diameter surface of the outer member 1 by bolts 37. Specifically, each of these bolts 37 is inserted into a bolt insertion hole 38 provided in the contact fixing portion 21a in the radial direction, and is screwed into a bolt hole 39 provided in the outer peripheral portion of the outer member 1. . In addition, as a fixing method of the contact fixing | fixed part 21a, you may use an adhesive agent etc. besides the fastening by the volt | bolt 37. FIG. At locations other than the contact fixing portion 21 a of the strain generating member 21, a gap is generated between the outer member 1 and the outer diameter surface. Other configurations are the same as those of the embodiment shown in FIGS. 7 is a cross-sectional view taken along arrow VII-VII in FIG. 8 showing a front view of the outer member 1 of the wheel bearing as viewed from the outboard side.

  FIG. 10 shows still another embodiment of the present invention. In this sensor-equipped wheel bearing, in the embodiment shown in FIGS. 1 to 6, the two sensor units 20 are connected to the upper surface portion and the lower surface portion of the outer diameter surface of the outer member 1 that is located above the tire ground contact surface. In addition to a pair of sensor units 19 composed of two sensor units 20 arranged in the above, 2 arranged on the right surface portion and the left surface portion of the outer diameter surface of the outer member 1 which is the front and rear position with respect to the tire ground contact surface. Another pair of sensor units 19 composed of one sensor unit 20 is provided. Other configurations are the same as those of the embodiment of FIGS.

  In the case of this configuration, the two sensor units 20 act on the wheel bearings or the tires from the detection signals of the pair of sensor unit pairs 10 arranged on the upper surface portion and the lower surface portion of the outer diameter surface of the outer member 1. The load Fz acting in the vertical direction or the load Fy in the axial direction can be accurately estimated. Further, the load Fx as the driving force is accurately estimated from the detection signals of the other pair of sensor units 10 in which the two sensor units 20 are arranged on the right and left surfaces of the outer diameter surface of the outer member 1. it can. That is, under any load condition, the vertical load Fz, the axial load Fy, and the load Fx as a driving force can be accurately detected.

In each of the above-described embodiments, the case where the outer member 1 is a fixed side member has been described. However, the present invention can also be applied to a wheel bearing in which the inner member is a fixed side member. In this case, the sensor unit 20 is provided on the peripheral surface that is the inner periphery of the inner member.
In these embodiments, the case where the present invention is applied to a third generation type wheel bearing has been described. However, the present invention is applicable to a first generation or second generation type wheel in which a bearing portion and a hub are independent parts. The present invention can also be applied to a bearing or a fourth-generation type wheel bearing in which a part of the inner member is composed of an outer ring of a constant velocity joint. Further, this sensor-equipped wheel bearing can be applied to a wheel bearing for a driven wheel, and can also be applied to a tapered roller type wheel bearing of each generation type.

It is a figure showing combining the sectional view of the wheel bearing with a sensor concerning one embodiment of this invention, and the block diagram of the conceptual composition of the detection system. It is the front view which looked at the outer member of the wheel bearing with a sensor from the outboard side. It is an enlarged plan view of a sensor unit in the wheel bearing with sensor. FIG. 4 is a cross-sectional view taken along arrow IV-IV in FIG. 3. It is sectional drawing which shows the other example of installation of a sensor unit. It is a wave form diagram of the output signal of the sensor unit in the bearing for wheels with the sensor. It is sectional drawing of the bearing for wheels with a sensor concerning other embodiment of this invention. It is the front view which looked at the outer member of the wheel bearing with a sensor from the outboard side. It is an expanded sectional view of the sensor unit in the wheel bearing with the sensor. It is the front view which looked at the outward member of the bearing for wheels with a sensor concerning further another embodiment of this invention from the outboard side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Outer member 1a ... Body mounting flange 1aa ... Projection piece 1c ... Groove 2 ... Inner member 3, 4 ... Rolling surface 5 ... Rolling element 14 ... Knuckle mounting bolt hole 16 ... Knuckle 19 ... Sensor unit pair 20 ... Sensor unit 21 ... Strain generating member 21a ... Contact fixing part 21b ... Notch part 22 ... Sensor 30 ... Estimation means

Claims (9)

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,
The strain generating member having two or more contact fixing portions fixed in contact with the fixed side member of the outer member and the inner member, and the strain generating member attached to the strain generating member One or more sensor units each including a sensor to be detected are provided, the strain generating member has a notch between the contact fixing parts, and a corner of the notch has an arcuate cross section. Wheel bearing with sensor.   The sensor-equipped wheel bearing according to claim 1, wherein the strain generating member is a thin plate material having a planar shape in a planar shape and a notch portion on a side portion.   3. The sensor unit according to claim 1, wherein the sensor unit includes a fixed side so that the two contact fixing portions of the distortion generating member are located at the same axial direction position of the fixed side member and spaced apart from each other in the circumferential direction. A wheel bearing with a sensor disposed on the outer diameter surface of a member.   3. The sensor unit according to claim 1, wherein the sensor unit includes a fixed side so that the two contact fixing portions of the distortion generating member are located at the same circumferential position of the fixed side member and spaced apart from each other in the axial direction. A wheel bearing with a sensor disposed on the outer diameter surface of a member.   In any one of Claims 1 thru | or 4, The flange for a vehicle body attachment attached to a knuckle is provided in the outer periphery of the said fixed side member, The bolt hole is provided in the circumferential direction several places, The said The flange is a projecting piece in which the circumferential portion provided with each bolt hole protrudes to the outer diameter side than the other portion, and the two contact fixing portions of the strain generating member are located between the adjacent projecting pieces. The wheel bearing with a sensor arrange | positioned at the outer-diameter surface of the fixed side member used as this.   6. The sensor-equipped wheel according to claim 1, wherein the sensor unit is disposed at an axial position around the outboard side rolling surface of the double row rolling surfaces. 7. Bearings.   7. The sensor-equipped wheel bearing according to claim 3, wherein the contact fixing portion of the strain generating member is fixed to an outer diameter surface of the fixed side member via a spacer. 7. The sensor-equipped wheel bearing according to claim 3, wherein a groove is provided between the fixed positions of the two contact fixing portions of the sensor unit on the outer diameter surface of the fixed-side member.   9. The sensor unit according to claim 1, wherein the fixed-side member includes two sets of the sensor units arranged at a position forming a phase difference of 180 degrees in the circumferential direction. 10. A wheel bearing with sensor provided with at least one pair.

Images