JP5264206B2 - Wheel bearing with sensor - Google Patents

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

  Furthermore, a sensor unit comprising a strain generating member and a strain sensor attached to the strain generating member is attached to a fixed ring of the bearing, and the strain generating member has at least two contact fixing portions with respect to the fixed ring, A sensor-equipped wheel bearing has been proposed that 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 3).

According to the sensor-equipped wheel bearing disclosed in Patent Document 3, 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 2002-098138 A Special table 2003-530565 gazette JP 2007-57299 A

In the technique disclosed in Patent Document 1, distortion generated by deformation of the flange portion of the fixed ring is detected. However, the deformation of the flange portion of the fixed ring involves slipping when a force exceeding the static friction force is applied between the flange surface and the knuckle surface, so that hysteresis is generated in the output signal when a repeated load is applied. There is a problem.
For example, when the load in a certain direction with respect to the wheel bearing increases, the static friction force between the fixed ring flange surface and the knuckle surface does not slip at first, but exceeds a certain size. And it comes to slip over the static friction force. If the load is reduced in this state, it will not slip due to static friction force at first, but it will slip when it reaches a certain size. As a result, when an attempt is made to estimate the load at a portion where this deformation occurs, a hysteresis as shown in FIG. 11 occurs in the output signal. When hysteresis occurs, the detection resolution decreases.
When a strain gauge is attached to the outer ring as in Patent Document 2, there is a problem in assemblability.
Further, in the sensor-equipped wheel bearing disclosed in Patent Document 3, the thickness between the outer diameter surface of the bearing fixed ring to which the sensor unit is attached and the inner rolling surface is thin, and the outer diameter surface of the fixed ring is Because there is a hardened part, the sensor unit cannot be firmly fixed. For this reason, slip occurs between the sensor unit and the outer diameter surface of the fixed ring of the bearing, and hysteresis due to the slip occurs in the output signal of the sensor unit, and the load cannot be detected with high accuracy.

  An object of the present invention is to provide a wheel bearing with a sensor that can firmly detect a load acting on a wheel bearing or a tire ground contact surface by firmly fixing the load detecting means to the bearing without slipping.

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 A thick-walled portion that is partially thick is provided in a part of the rim, and load detecting means for detecting a load acting on the wheel bearing is fixed to the surface of the thick-walled portion.
According to this configuration, since the load detection means is fixed to the surface of the thick part of the fixed side member, the fixation becomes firm, and slippage between the load detection means and the fixed side member can be suppressed, Hysteresis due to the slip appearing in the output signal of the load detecting means can be reduced. As a result, the load acting on the wheel bearing can be accurately detected.

Before KiAtsu meat portion, a portion of the circumferential direction of the stationary member, in which a thicker than other portions of the circumferential direction.

  In this invention, it is good also considering the installation surface of the said load detection means in the thick part of the said fixed side member as a flat surface. In the case of this configuration, the load detection means can be stably fixed to the surface of the thick portion.

In the present invention, the load detecting means includes a strain generating member having two or more contact fixing portions fixed in contact with the surface of the thick portion of the fixed side member, and the strain generating member attached to the strain generating member. The contact unit may include a sensor unit having a sensor for detecting distortion of the generation member, and the contact fixing portions may be provided so as to have the same dimension in the axial direction with respect to the thick portion surface of the fixing side member.
In the case of this configuration, since two or more contact fixing portions of the strain generating member in the sensor unit are fixed in contact with the fixed side member, the strain of the fixed side member is enlarged and transmitted to the strain generating member. It is detected with high sensitivity by the sensor, and the load can be detected from the output signal.
Moreover, if the axial dimension of each contact fixing part of the sensor unit fixed to the surface of the thick part of the fixed side member is different, the strain transmitted from the fixed side member to the strain generating member via the contact fixing part is also different. . In the case of this configuration, since each contact fixing part of the sensor unit is provided so as to have the same dimension in the axial direction with respect to the surface of the thick part of the fixed side member, the distortion is likely to concentrate on the distortion generating member, The detection sensitivity is improved accordingly.

In the present invention, the strain generating member may be made of a strip having a uniform width in a planar shape or a thin plate material having a planar shape in a strip shape and having a notch in a side portion.
If the strain generating member is a thin plate material, the distortion of the fixed side member is easily transmitted to the strain generating member, the strain is detected with high sensitivity by the sensor, the hysteresis generated in the output signal is also reduced, and the load is accurate. It can be detected well. In addition, the shape of the strain generating member is simple, and the mass productivity is excellent. When the distortion generating member is a strip having a uniform plane shape, the shape is further simplified, and mass productivity is improved. Further, if the distortion generating member has a planar outline and has a notch in the side portion, the distortion of the fixed side member is further enlarged and transmitted to the distortion generating member, so that the load is more accurately applied. Can be detected.

  In this invention, you may provide a groove | channel between the fixing positions of the contact fixing part which the said sensor unit adjoins in the thick part surface of the said fixed side member. In the case of this configuration, without interposing a spacer between the contact fixing part and the thick part, the intermediate part of the adjacent contact fixing part of the strain generating member is separated from the surface of the thick part to improve the detection sensitivity. The sensor unit mounting structure can be simplified.

  In this invention, you may form the thick part of the said fixed side member, or a thick part and the said groove | channel by forging. In the case of this configuration, the thick part and the groove can be formed in the forging process of the fixed side member, so that the thick part and the groove can be easily formed without increasing the manufacturing process.

  In this invention, you may arrange | position the said sensor unit in the upper surface part of the outer diameter surface of the said fixed side member which becomes a vertical position and a left-right position with respect to a tire ground-contact surface, a lower surface part, a right surface part, and a left surface part. In the case of this configuration, it is possible to accurately detect the vertical load Fz, the axial load Fy, and the load Fx caused by the driving force and braking force acting on the wheel bearing.

The sensor-equipped wheel bearing according to the present invention includes an outer member having a double-row rolling surface formed on the inner periphery, an inner member having a rolling surface 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 A thick wall part that is partially thick is provided in a part of the wheel, and a load detecting means for detecting a load acting on the wheel bearing is fixed to the surface of the thick wall part, and the thick wall part is fixed. a part of the circumferential direction of the side members, because the is obtained by a thicker than other portions of the circumferential direction and can be fixed to firmly bearing without slippage load detecting means, wheel bearing and the tire contact The load acting on the ground can be accurately detected.

  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. Bolt holes 14 for mounting the vehicle body are provided at a plurality of locations in the circumferential direction on the flange 1a, and knuckle bolts 18 inserted into the bolt insertion holes 17 of the knuckle 16 from the inboard side are screwed into the bolt holes 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.

Two sensor units 20 are provided on the outer diameter surface of the outer member 1 which is a fixed member as load detecting means for detecting a load acting on the wheel bearing. 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. Here, the two sensor units 20 are provided at two locations, the upper surface portion and the lower surface portion, on the outer diameter surface of the outer member 1 that are in the vertical position with respect to the tire ground contact surface, so that the vertical direction acts on the wheel bearing. The load (vertical load) Fz 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.
The upper part and the lower part in which each sensor unit 20 that is a part of the outer member 1 in the circumferential direction is installed are thicker with the outer diameter surface projecting to the outer diameter side than the other parts in the circumferential direction. The thick portion 1b is formed. The sensor units 20 are fixed to the surfaces of the thick portions 1b. The thick part 1 b is formed in the forging of the outer member 1. Thereby, the thick part 1b can be formed easily, without increasing a manufacturing process.

  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 plate having a thickness of 3 mm or less, such as a steel material, and has a flat planar shape with a constant width over the entire length, and has notches 21b on both sides of the center. In addition, the planar outline of the strain generating member 21 may be a monotonous belt without the notch 21b. In addition, the strain generating member 21 has two contact fixing portions 21 a at both ends that are fixed to the surface of the thick portion 1 b of the outer member 1 through spacers 23. 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, the central part sandwiched between the notches 21b on both sides on the outer surface side of the strain generating member 21 is selected as the part. 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 sensor unit 20 is arranged such that the two contact fixing portions 21a of the strain generating member 21 are located at positions having the same dimension in the axial direction of the outer member 1 and being spaced apart from each other in the circumferential direction. These contact fixing portions 21a are fixed to the surface of the thick portion 1b of the outer member 1 by bolts 24 through spacers 23, respectively. Each of the bolts 24 is inserted into a bolt insertion hole 26 of the spacer 23 from a bolt insertion hole 25 penetrating in the radial direction provided in the contact fixing portion 21 a, and a bolt provided in the thick portion 1 b of the outer member 1. Screwed into the hole 27. Thus, by fixing the contact fixing portion 21a to the surface of the thick portion 1b of the outer member 1 through the spacer 23, the central portion having the notch portion 21b in the thin plate-like strain generating member 21 is thick. It will be in the state away from the surface of the meat part 1b, and distortion deformation of the periphery of the notch part 21b will become 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 surface of the thick portion 1b of the outer member 1, it is desirable that the surface of the thick portion 1b be a flat surface.

  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. Based on the output signal of the sensor 22, the estimating means 30 is a force acting on the wheel bearing or between the wheel and the road surface (tire contact surface) (vertical load Fz, load Fx serving as driving force or braking force, axial load Fy). And includes a signal processing circuit and a correction circuit. The estimation means 30 has a relationship setting means (not shown) in which the relationship between the acting force and the output signal of the sensor 22 is set by an arithmetic expression or a table, and the relationship setting means is determined from the input output signal. Used to output the value of the acting force. 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 in the sensor unit 20 are fixed to the outer member 1, the strain of the outer member 1 is transmitted to the strain generating member 21 in an enlarged manner, and the strain is transmitted to the sensor. 22 is detected with high sensitivity, and the load can be estimated from the output signal. In particular, since the sensor unit 20 that is the load detecting means is fixed to the surface of the thick portion 1b that is the outer diameter surface of the outer member 1 that is the stationary member, the sensor is moved to the outer diameter surface of the outer member 1. By firmly fixing the unit 20, slipping between the sensor unit 20 and the outer diameter surface of the outer member 1 can be suppressed, and hysteresis due to the slip appearing in the output signal of the sensor 22 can be reduced. it can. As a result, the load can be estimated with high accuracy.

  If the axial dimension of each contact fixing portion 21a of the sensor unit 20 fixed to the outer diameter surface (the surface of the thick portion 1b) of the outer member 1 which is a fixed member is different, the outer diameter surface of the outer member 1 The strain transmitted to the strain generating member 21 through the contact fixing portion 21a is also different. In this embodiment, the contact fixing portions 21a of the sensor unit 20 are provided so as to have the same dimension in the axial direction with respect to the surface of the thick portion 1b of the outer member. It becomes easier to concentrate and the detection sensitivity is improved accordingly.

  Further, since the strain generating member 21 is made of a thin plate material, the strain of the outer member 1 is easily transmitted to the strain generating member 21 in an enlarged manner. It becomes smaller and the load can be estimated with high accuracy. In addition, the shape of the strain generating member 21 is simple, and the mass productivity is excellent. When the strain generating member 21 is a belt having a monotonous planar outline, the shape is further simplified, and mass productivity is improved. Further, when the strain generating member 21 has a planar outline as shown in FIG. 3 and has a notch portion 21b on the side portion, the strain of the outer member 1 is further enlarged and transmitted to the strain generating member 21. Therefore, the load can be estimated with higher accuracy.

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, 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, for the vertical load Fz, the outer member 1 that is a fixed member is deformed at the upper surface portion and the lower surface portion. In this embodiment, the two sensor units 20 are moved up and down with respect to the tire ground contact surface. Since the outer member 1 is positioned on the upper surface and the lower surface of the outer diameter surface, the axial load Fy and the vertical load Fz can be accurately estimated from the output signals of the sensors 22.

  As another installation example of the sensor unit 20, as shown in FIG. 5, the upper surface portion of the outer diameter surface of the outer member 1 that is in the vertical position and the horizontal position with respect to the tire ground contact surface, You may arrange | position to a lower surface part, a right surface part, and a left surface part. In this case, a thick portion 1b similar to the thick portion 1b of the upper surface portion and the lower surface portion is also provided on the right surface portion and the left surface portion of the outer diameter surface of the outer member 1, and the surface of the thick portion 1b The sensor unit 20 is fixed. For the load Fx caused by the driving force or the braking force, the right surface portion and the left surface portion of the outer member 1 that is a fixed member are deformed. In this case, the driving force or The load Fx caused by the braking force can be accurately estimated. That is, when the sensor unit 20 is 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 outer member 1, the vertical load Fz, the axial load Fy, the driving force and the braking force Can accurately estimate the load Fx.

  6 and 7 show another embodiment of the present invention. In this embodiment, in the sensor-equipped wheel bearing of the embodiment shown in FIGS. 1 to 4, as shown in an enlarged cross-sectional view in FIG. 7, the outer diameter surface of the outer member 1 (the surface of the thick portion 1 b). By providing the groove 1c in two intermediate portions where the two contact fixing portions 21a of the strain generating member 21 are fixed, the spacer 23 is omitted, and the two contacts where the notch portion 21b in the strain generating member 21 is located. The intermediate part of the fixing part 21a is separated from the surface of the thick part 1b of the outer member 1. In this case, the thick portion 1b and the groove 1c on the surface thereof are formed in the forging of the outer member 1. Thereby, the thick part 1b and the groove | channel 1c can be formed easily, without increasing a manufacturing process. Other configurations are the same as those in the embodiment of FIGS.

  As described above, when the groove 1c is provided at the two intermediate portions where the two contact fixing portions 21a are fixed on the surface of the thick portion 1b, the spacer 23 is omitted and the intermediate portion of the strain generating member 21 is the thick portion. Since it can remove | separate from the surface of 1b, the attachment structure of the sensor unit 20 to the thick part 1b becomes simple.

8 to 10 show still another embodiment of the present invention. In this sensor-equipped wheel bearing, in the embodiment shown in FIGS. 1 to 4, the sensor unit 20 is 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. As shown in FIG. 9, the outer member 1 is provided with a thick part 1 b in which a part of the outer diameter surface projects to the outer diameter side, and two contact fixing parts 21 a are fixed to the surface of the thick part 1 b. This is the same as the embodiment of FIGS. 8 shows a cross-sectional view taken along arrow VIII-VIII in FIG. 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. It arrange | positions at the thick part 1b surface of the direction member 1. FIG. 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 surface of the thick part 1b of the outer member 1, it is desirable to form the surface of the thick part 1b as a flat surface.
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. The strain sensor 22 is affixed to a location where the strain increases with respect to the load in each direction on the strain generating member 21. Here, as the location, the position around the notch portion 21b, specifically, the outer surface side of the strain generating member 21 and the back side of the notch portion 21b is selected, and the strain sensor 22 is the notch portion. The distortion around 21b is detected.

  The two contact fixing portions 21a of the strain generating member 21 are fixed by fastening to the surface of the thick portion 1b of the outer member 1 with bolts 47, respectively. Specifically, each of these bolts 47 is inserted into a bolt insertion hole 48 provided in the contact fixing portion 21a in the radial direction and screwed into a bolt hole 49 provided in the outer peripheral portion of the outer member 1. . In addition, as a fixing method of the contact fixing part 21a, in addition to fastening with the bolt 47, an adhesive or the like may be used. 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.

  In this embodiment, in addition to the sensor unit 20, a rotation detector 40 for detecting the rotation of the inner member 2 is provided as shown in FIG. The rotation detector 40 is an axial rotation detector including a magnetic encoder 51 shared by the slinger of the inboard side seal 8 and a magnetic sensor 52 facing the magnetic encoder 51 in the axial direction. .

The sensor 22 of the sensor unit 20 and the magnetic sensor 52 of the rotation detector 40 are connected to the averaging processing means 29. The averaging processing means 29 is means for averaging the output signal of the sensor 22.
Since the sensor unit 20 is provided at an axial position around the rolling surface 3 in the outboard side row of the outer member 1, the output signal of the sensor 22 is affected by the rolling elements 5. That is, when the rolling element 5 passes through the position closest to the sensor 22 in the sensor unit 20, the amplitude of the output signal of the sensor 22 has a peak value, and decreases as the rolling element 5 moves away from the position. Since the rolling elements 5 sequentially pass through the vicinity of the installation portion of the sensor unit 20 at a predetermined arrangement pitch, the output signal of the sensor 22 has a waveform whose amplitude is the arrangement pitch of the rolling elements. Therefore, the averaging processing means 29 averages the amplitude of the output signal during the period in which the rolling elements 5 revolve by the arrangement pitch to eliminate the influence of the rolling elements 5. An estimation unit 30 is provided in the next stage of the averaging processing unit 29. The estimation means 30 calculates the force (vertical load Fz, drive) acting on the wheel bearing or between the wheel and the road surface (tire contact surface) from the average value of the output signal of the sensor 22 obtained by the averaging processing means 29. The load Fx and the axial load Fy) are estimated. Other configurations are the same as those in the embodiment of FIGS.

In each of the above embodiments, the case where the outer member 1 is a fixed side member has been described. However, the present invention can also be applied to a wheel bearing in which the inner member is a fixed side member. In this case, the sensor unit 20 is provided on the peripheral surface that is the inner periphery of the inner member.
In each of the above embodiments, the case where the present invention is applied to a third generation type wheel bearing has been described. However, the present invention is for a first or second generation type wheel in which the bearing portion and the hub are independent parts. The present invention can also be applied to a bearing or a fourth-generation type wheel bearing in which a part of the inner member is composed of an outer ring of a constant velocity joint. The sensor-equipped wheel bearing can also 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 a front view of the outward member which shows the other example of installation of a sensor unit. It is the front view which looked at the outward member of the bearing for wheels with a sensor concerning other embodiments of this invention from the outboard side. It is an expanded sectional view of the sensor unit in the wheel bearing with the sensor. It is a figure which combines and shows the sectional view of the wheel bearing with a sensor concerning further another embodiment of this invention, and the block diagram of the conceptual structure of the detection system. It is the front view which looked at the outer member of the wheel bearing with a sensor from the outboard side. It is an expanded sectional view of the sensor unit in the wheel bearing with the sensor. It is explanatory drawing of the hysteresis in the output signal in a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Outer member 1b ... Thick part 1c ... Groove 2 ... Inner member 3, 4 ... Rolling surface 5 ... Rolling body 20 ... Sensor unit (load detection means)
21 ... Strain generating member 21a ... Contact fixing part 21b ... Notch part 22 ... Sensor

Claims (7)

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 part of the fixed member of the outer member and the inner member is provided with a thick portion that is partially thick, and load detecting means for detecting a load acting on the wheel bearing is provided with the thick wall portion. fixed on the surface of the part, the thick section, a portion of the circumferential direction of the stationary member, for the sensor with a wheel, wherein the this is obtained by a thicker than other portions of the circumferential direction bearing. The sensor-equipped wheel bearing according to claim 1 , wherein an installation surface of the load detection means in the thick part of the fixed side member is a flat surface. 3. The strain generating member according to claim 1 , wherein the load detecting means includes two or more contact fixing portions that are fixed in contact with the surface of the thick portion of the fixed side member, and the strain generating member. The sensor unit includes a sensor unit that is attached and detects a strain of the strain generating member, and each of the contact fixing portions is provided to have the same dimension in the axial direction with respect to the surface of the thick portion of the fixing side member. Bearing for wheel with sensor. 4. The sensor-equipped wheel bearing according to claim 3 , wherein the strain generating member is a strip having a uniform planar width, or a thin plate material having a planar planar shape and having a notch in a side portion. 5. The sensor-equipped wheel bearing according to claim 3 or 4 , wherein a groove is provided between fixing positions of adjacent contact fixing portions of the sensor unit on a surface of the thick portion of the fixed side member. 6. The sensor-equipped wheel bearing according to claim 5 , wherein the fixed-side member has a thick portion or a thick portion and the groove formed by forging. The sensor unit according to any one of claims 3 to 6 , wherein the sensor unit is an upper surface portion, a lower surface portion, a right surface portion of an outer diameter surface of the fixed side member that is in a vertical position and a horizontal position with respect to a tire ground contact surface. And a wheel bearing with sensor arranged on the left side.

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