JP4986759B2 - 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 distortion of an outer diameter surface of an outer ring flange of the wheel bearing has been proposed (for example, Patent Document 1). . In addition, a wheel bearing has been proposed in which a strain increasing mechanism composed of an L-shaped member is attached to the flange portion and the outer diameter portion of the fixed ring, and a strain gauge is attached to a part of the strain expanding mechanism (for example, Patent Documents). 2).
JP 2002-098138 A JP 2006-0777807 A

In the technique disclosed in Patent Document 1, distortion generated by deformation of the flange portion of the fixed ring is detected. However, since the deformation of the flange portion of the fixed ring involves friction (slip) between the flange surface and the knuckle surface, there is a problem that hysteresis is generated in the output signal when a repeated load is applied.
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. 13 occurs in the output signal.
Also in the technique disclosed in Patent Document 2, the portion fixed to the flange surface of the distortion expanding mechanism made of an L-shaped member is affected by the friction (slip) between the flange surface and the knuckle surface. Problems arise.
Further, when detecting the load Fz in the vertical direction acting on the wheel bearing, the amount of deformation of the fixed wheel with respect to the load Fz is small, so that the amount of distortion is small.

  An object of the present invention is to provide a sensor-equipped wheel bearing capable of accurately detecting a load applied to a wheel without being affected by hysteresis.

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 strain generating member having two contact fixing portions fixed in contact with the outer diameter surface and a notch portion positioned between the two contact fixing portions, and an attachment to the strain generating member One or more sensor units having a sensor for detecting the distortion of the distortion generating member are provided, and the two contact fixing portions of the sensor unit are arranged at the same phase position in the circumferential direction of the fixed side member. And one of the two contact fixing parts is the Of the rolling surfaces of the row, in the axial position around the rolling surface on the outboard side, the other one contact fixing part is further arranged on the outboard side than the one contact fixing part, The notch part of the sensor unit is arranged on the outboard side from the center position between the two contact fixing parts.
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. Here, one contact fixing portion of the strain generating member in the sensor unit is fixed to an axial position around the rolling surface of the outboard side row on the outer diameter surface of the outer member, and this axial position Is a part where the load applied to the ground contact surface of the tire is transmitted from the inner member through the rolling elements, and thus the part has a relatively large deformation amount. On the other hand, the other one contact fixing portion of the strain generating member is further fixed at an axial position on the outboard side than the one contact fixing portion, and this axial position is compared with the previous axial position. It becomes a site | part with a small deformation amount. As a result, the distortion of the outer diameter surface of the outer member is enlarged and transmitted to the distortion generating member, and the enlarged distortion is detected by the sensor. In addition, the amount of deformation that occurs in the outer member due to the application of a load differs at each position in the axial direction. Since the same phase is fixed in the circumferential direction, the strain tends to concentrate on the strain generating member, and the detection sensitivity is improved accordingly. Further, since the notch is provided in the strain generating member of the sensor unit, and the sensor is provided around the notch, the strain transmitted from the outer diameter surface of the outer member to the strain generating member is enlarged. Becomes easier to concentrate on the notch, and the detection sensitivity of the sensor is further improved. In addition, since the notch portion is disposed on the outboard side with respect to the center position between the two contact fixing portions of the strain generating member, the contact fixing portion and the notch that are fixed at the axial position where the deformation amount is large. The distance to the portion becomes longer, the moment acts, the periphery of the notch is deformed, and the distortion concentrates around the notch, further improving the detection sensitivity. As described above, since the sensor unit is not fixed to the projecting piece of the outer member flange which is a main cause of hysteresis, the hysteresis generated in the output signal of the sensor is reduced, and the load can be accurately detected. . Thereby, it is possible to accurately detect the load applied to the wheel without being affected by hysteresis.

  In this invention, the notch part of the sensor unit may be notched from the outer surface side to the inner surface side of the strain generating member. In the case of this configuration, one contact fixing portion is fixed at an axial position around the outboard side rolling surface with a relatively large deformation amount on the outer diameter surface of the outer member, and the other one contact fixing portion. Is fixed at an axial position on the outboard side where the amount of deformation is relatively small, the deformation of the outer diameter surface of the outer member causes the periphery of the notch to be pulled, and the distortion around the notch And the load can be estimated with higher sensitivity.

  In the present invention, the notch portion of the sensor unit may be further notched in the width direction from both side surfaces in the width direction orthogonal to the arrangement direction of the two contact fixing portions of the strain generating member. In the case of this configuration, the strain is not dispersed and tends to concentrate on a part, so that the load can be estimated with higher sensitivity.

  In this invention, the width dimension of the notch of the sensor unit may be 2 mm or less. If the width of the notch is wide, the strain will disperse. However, if the width of the notch is set to 2 mm or less, the strain will not disperse and it will be easier to concentrate on the part. can do.

  In the present invention, the strain generating member of the sensor unit may be plastically deformed even in a state in which an 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 to not. If plastic deformation occurs before the assumed maximum force is applied, the deformation of the outer member will not be transmitted accurately to the sensor unit and will affect the strain measurement. It is desirable that plastic deformation does not occur even in a state where is applied.

  In the present invention, the sensor unit may be provided with the sensor around the notch of the strain generating member, and the entire predetermined surface portion including the sensor installation surface of the strain generating member may be a flat surface. In the case of this configuration, processing of the sensor unit and installation of the sensor are facilitated.

  In the present invention, the entire surface of the predetermined surface portion including the sensor installation surface in the strain generating member is a flat surface, and the sensor is formed by printing and baking on the sensor installation surface of the strain generating member. Further, an electrode and a strain measuring resistor may be formed by printing and baking. In the case of this configuration, the sensor can be easily formed on the strain generating member. When the sensor is formed in this manner, the adhesive strength is not lowered due to a change in diameter as in the case where the strain generating member is fixed to the sensor installation surface with an adhesive, and the reliability of the sensor unit can be improved. Further, since the processing is easy, the cost can be reduced.

  In the present invention, the entire surface of the predetermined surface portion including the sensor installation surface of the strain generating member of the sensor unit may be a flat surface, and the strain generating member may be fixed to the outer diameter surface of the fixed side member via a spacer. When the predetermined surface portion including the sensor installation surface in the strain generating member is an inner surface facing the outer diameter surface of the fixed side member, the fixed side member A gap is formed between the outer diameter surface and the sensor can be easily installed in the vicinity of the notch without interfering with the outer diameter surface of the stationary member.

  In this invention, a sensor is provided around the notch portion of the strain generating member, the entire surface of the predetermined surface portion including the sensor installation surface in the strain generating member is a flat surface, and the sensor unit on the outer diameter surface of the fixed side member A groove may be provided between the fixing positions of the two contact fixing portions. Thus, when the groove is provided on the outer diameter surface of the fixed side member, when the flat surface of the strain generating member is the inner surface facing the outer diameter surface of the fixed side member, the two contact fixing portions are fixed to the fixed side member. Even if it is directly fixed to the outer diameter surface of the member, a gap is created between the outer diameter surface of the fixed side member and the inner surface of the strain generating member that is a flat surface, so that the sensor also interferes with the outer diameter surface of the fixed side member. It can be easily installed in the vicinity of the notch without any need to do so.

  In this 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 is a circle in which each bolt hole is provided. The circumferential part may be a protruding piece that protrudes to the outer diameter side from the other part, and the sensor unit may be arranged at the center between the adjacent protruding pieces. In the case of this configuration, the sensor unit is provided at a position away from the projecting piece causing the hysteresis, the hysteresis of the output signal of the sensor is further reduced, and the load can be detected with higher accuracy.

  In the present invention, one of the sensor units may be provided on the upper surface portion of the outer diameter surface of the outer member with respect to the tire ground contact surface. In the case of this configuration, even when a vertical load Fz or a longitudinal load Fy is applied to the outer diameter surface of the outer member, the position where the rolling element load is always applied, that is, the upper surface with respect to the tire ground contact surface If one sensor unit is provided at a position to be a part, the load can be detected with high accuracy in any case.

In the present invention, an estimation means for estimating an external force acting on the wheel bearing or an acting force between the tire and the road surface may be provided based on the output signal of the sensor.
When the force between the tire and the road surface is estimated by the estimation means based on the output signal of the sensor, the force between the tire and the road surface of the wheel can be detected with high sensitivity regardless of when stationary or at low speed. Not only the acting force but also the force acting on the wheel bearing (for example, the preload amount) can be estimated by the estimating means.

In this invention, the estimating means is an external force acting on the wheel bearing by at least one of an absolute value of the sensor signal, an average value of the output signal, and an amplitude of the output signal, or The acting force between the tire and the road surface may be estimated.
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, the passage speed of the rolling element, that is, the rotational speed of the wheel can be detected by measuring the period of the amplitude in the detection signal by the estimation means. Thus, when the output signal varies, the acting force can be calculated from the average value and amplitude of the output signal. When there is no change, the acting force 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 A strain generating member having two contact fixing portions fixed in contact with the outer diameter surface and a notch portion positioned between the two contact fixing portions, and an attachment to the strain generating member One or more sensor units having a sensor for detecting the distortion of the distortion generating member are provided, and the two contact fixing portions of the sensor unit are arranged at the same phase position in the circumferential direction of the fixed side member. And one of the two contact fixing parts is the Of the rolling surfaces of the row, in the axial position around the rolling surface on the outboard side, the other one contact fixing part is further arranged on the outboard side than the one contact fixing part, Since the notch portion of the sensor unit is disposed on the outboard side with respect to the center position between the two contact fixing portions, it is possible to accurately detect the load applied to the wheel without being affected by hysteresis.

  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 formed with the surface 4 and the double row rolling elements 5 interposed between the outer member 1 and the rolling surfaces 3 and 4 of the inner member 2 are constituted. 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.

  A sensor unit 19 is provided on the outer diameter surface of the outer member 1 that is a stationary member. Here, the two sensor units 19 are provided in two locations, the upper surface portion and the lower surface portion, on the outer diameter surface of the outer member 1 that is located above the tire ground contact surface, so that the vertical direction acts on the wheel bearing. The load Fz is detected. Specifically, as shown in FIG. 2, one sensor unit 19 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 sensor unit 19 is arranged at the center between the two adjacent projecting pieces 1aa on the lower surface portion of the outer diameter surface.

  As shown in an enlarged sectional view in FIG. 3, these sensor units 19 include a strain generating member 20 and a sensor 21 that is attached to the strain generating member 20 and detects the strain of the strain generating member 20. The strain generating member 20 is made of an elastically deformable metal material such as a steel material. The strain generating member 20 has two contact fixing portions 20a projecting on the inner surface facing the outer diameter surface of the outer member 1 at both ends, and these contact fixing portions 20a are formed on the outer diameter surface of the outer member 1. Directly fixed. Of the two contact fixing portions 20a, one contact fixing portion 20a 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 20a is arranged at the position, and both the contact fixing portions 20a are arranged at the same phase position in the circumferential direction of the outer member 1. 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 19 to the outer diameter surface of the outer member 1, a flat portion is provided at a location where the contact fixing portion 20 a of the strain generating member 20 is contact-fixed on the outer diameter surface of the outer member 1. It is desirable to form.

  Further, a notch portion 20b is formed on the outboard side from the center position between the two contact fixing portions 20a of the strain generating member 20. 4A and 4B, a front view and a bottom view of one configuration example of the sensor unit 19 (a view seen from the inner surface facing the outer diameter surface of the outer member 1) are shown in this example. The notch 20b has a shape that is notched from the outer surface side to the inner surface side of the strain generating member 20. The width dimension of the notch 20b is 2 mm or less. The sensor 21 is affixed to a location where the strain increases with respect to the load in each direction in the strain generating member 20. Here, as the location, the position around the notch 20b, specifically the position on the inner surface side of the strain generating member 20 and the back side of the notch 20b, is selected, and the sensor 21 has the notch 20b. Detect peripheral distortion. It should be noted that the strain generating member 20 is plastically deformed even in a state where the maximum force assumed 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 is applied. It is desirable not to do so. This is because when plastic deformation occurs, the deformation of the outer member 1 is not accurately transmitted to the sensor unit 19 and affects the measurement of strain. The maximum force assumed above is, for example, the maximum force that does not cause damage that impedes normal operation of the wheel bearing as a bearing.

  5A and 5B show a front view and a bottom view of another configuration example of the sensor unit 19. In this configuration example, compared to the embodiment shown in FIGS. 4A and 4B, the width direction from both side surfaces in the width direction orthogonal to the arrangement direction of the two contact fixing portions 20 a of the strain generating member 20. The notches 20b 'are formed by cutting each halfway toward the placement portion of the sensor 21 toward the end. Other configurations are the same as those in the configuration example of FIG.

  The contact fixing portion 20a of the strain generating member 20 is fixed to the outer diameter surface of the outer member 1 by using a bolt 23 inserted through a bolt insertion hole 22 provided in the contact fixing portion 20a in the radial direction. 1 is screwed into a bolt hole 24 provided on the outer peripheral portion of the 1 and fastened, but may be fixed with an adhesive or the like. At locations other than the contact fixing portion 20a of the strain generating member 20, a gap is generated between the outer member 1 and the outer diameter surface.

  The sensor 21 of the sensor unit 19 is connected to the estimation means 25. Here, the estimation means 25 is means for estimating the acting force between the tire of the wheel and the road surface from the output signal of the sensor 21, and includes a signal processing circuit and a correction circuit. The estimation means 25 has relationship setting means (not shown) in which the relationship between the acting force between the tire of the wheel and the road surface and the output signal of the sensor 21 is set by an arithmetic expression or a table or the like, and from the input output signal The acting force is output 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. For example, when the sensor unit 19 is installed on the projecting piece 1aa of the outer member flange 1a and the load is estimated from the deformation of the flange 1a, hysteresis occurs in the output signal as in the description of the conventional example.
Here, one contact fixing portion 20 a of the strain generating member 20 in the sensor unit 19 is fixed at an axial position that is the periphery of the rolling surface 3 of the outboard side row on the outer diameter surface of the outer member 1. This axial position is a portion where the load applied to the ground contact surface of the tire is transmitted from the inner member 2 via the rolling elements 5, and thus the portion having a relatively large amount of deformation. On the other hand, the other one contact fixing portion 20a of the strain generating member 20 is fixed to an axial position on the outboard side further than the one contact fixing portion 20a, and this axial position is the previous axial position. It becomes a part with a small amount of deformation compared to. As a result, the distortion of the outer diameter surface of the outer member 1 is enlarged and transmitted to the distortion generating member 20, and the enlarged distortion is detected by the sensor 21. Further, the amount of deformation generated in the outer member 1 due to the application of a load is different at each position in the axial direction, but here, the two contact fixing portions 20 a of the strain generating member 20 in the sensor unit 19 are connected to the outer member 1. Since the same phase is fixed in the circumferential direction with respect to the outer diameter surface, the strain tends to concentrate on the strain generating member 20, and the detection sensitivity is improved accordingly.

  In addition, since the notch 20b is provided in the strain generating member 20 of the sensor unit 19 and the sensor 21 is provided around the notch 20b, the strain generating member 20 is connected to the strain generating member 20 from the outer diameter surface of the outer member 1. The enlarged and transmitted distortion is easily concentrated on the notch 20b, and the detection sensitivity of the sensor 21 is further improved. Moreover, since the notch 20b is disposed on the outboard side of the center position between the two contact fixing portions 20a in the strain generating member 20, the contact fixing portion is fixed to the axial position where the deformation amount is large. The distance between 20a and notch 20b is increased, the moment acts and the periphery of notch 20b is deformed, strain is concentrated around notch 20b, and detection sensitivity is further improved.

  The estimating means 25 estimates the load acting on the wheel bearing from the output signal of the sensor 21. This makes it possible to detect the acting force between the wheel tire and the road surface with high sensitivity regardless of whether the vehicle is stationary or at low speed. As described above, since the sensor unit 19 is not fixed to the projecting piece 1aa of the outer member flange 1a which is a main cause of hysteresis, the hysteresis generated in the output signal of the sensor 21 is reduced, and the load is accurately estimated. can do.

  In this embodiment, when the cutout portion 20b of the sensor unit 19 is cut out from the outer surface side to the inner surface side of the strain generating member 20 as in the configuration example shown in FIG. The fixing portion 20a is fixed to an axial position around the outboard side rolling surface 3 having a relatively large deformation amount on the outer diameter surface of the outer member 1, and the other one contact fixing portion 20a is relatively deformed. Since the amount is further fixed at the axial position on the outboard side, the periphery of the notch 20b is pulled by the deformation of the outer diameter surface of the outer member 1, and the distortion of the periphery of the notch 20b is caused. The load becomes larger and the load can be estimated with higher sensitivity.

  Further, in this embodiment, the notch portion 20b of the sensor unit 19 is arranged in the width direction orthogonal to the arrangement direction of the two contact fixing portions 20a of the strain generating member 20 as in the configuration example shown in FIG. When the shape is cut out in the width direction from the both side surfaces, the strain is not dispersed and it becomes easy to concentrate on a part, so that the load can be estimated with higher sensitivity.

  Further, when the width of the cutout portion 20b is wide, the distortion is dispersed. However, in this embodiment, since the width dimension of the cutout portion 20b is 2 mm or less, the distortion is not further dispersed and concentrated in a part. Therefore, the load can be estimated with higher sensitivity.

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 of the bearing) is detected. It is good to do.
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, during the rotation of the wheel bearing, the amplitude of the output signal of the sensor 21 of the sensor unit 19 depends on the presence or absence of the rolling element 5 passing through the vicinity of the sensor unit 19 on the rolling surface 3 as shown in FIG. Periodic changes may occur as shown. The reason is that the amount of deformation differs between when the rolling element 5 passes and when it does not, and the amplitude of the output signal of the sensor 21 has a peak value for each passing period of the rolling element 5. Therefore, by measuring the period of the peak value in the detection signal by, for example, the estimating means 25, 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 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.

  In this embodiment, the sensor unit 19 is arranged on the outer diameter surface of the outer member 1 at a position corresponding to the center between the two adjacent projecting pieces 1aa of the outer member flange 1a. Thus, the sensor unit 19 is provided at a position away from the projecting piece 1aa that causes the above-described problem, and the hysteresis of the output signal of the sensor 21 is further reduced, so that the load can be estimated more accurately.

  Further, in this embodiment, even when a vertical load Fz or a longitudinal load Fy is applied to the outer diameter surface of the outer member 1, a position where the load of the rolling element 5 is always applied, that is, a tire ground contact surface. Since one sensor unit 19 is provided at a position that becomes the upper surface portion, the load can be accurately estimated in any case. Further, since the sensor unit 19 detects even a small strain in an enlarged manner, it can detect with high sensitivity even a load Fz in the vertical direction with a small deformation amount of the outer member 1.

In this embodiment, the following configuration is not particularly limited.
-Number of sensor units 19 installed, location, number of contact fixing parts 20a, sensors 21, and notches 20b-Shape and fixing method of sensor unit 19 (adhesion, welding, etc.)

  7 to 10 show another embodiment of the present invention. 8 shows a front view of the outer member 1 of the wheel bearing as viewed from the outboard side, and FIG. 7 shows a sectional view taken along arrow VII-VII in FIG. In this embodiment, in the sensor-equipped wheel bearing of the embodiment shown in FIGS. 1 to 3, as shown in FIG. It is fixed to the outer diameter surface of the outer member 1 via. Therefore, as shown in FIGS. 10A and 10B showing a front view and a bottom view of the sensor unit 19, the inner side surface of the strain generating member 20 including the installation surface of the sensor 21 is the same as in the previous embodiment. Thus, the contact fixing portion 20a does not protrude to the inner surface side, and the entire surface is a flat surface. Other configurations are the same as those in the previous embodiment.

  As a result, in a fixed state where the strain generating member 20 is fastened to the outer diameter surface of the outer member 1 with the bolts 23 via the spacers 26, the outer side of the inner surface of the strain generating member 20 is outside the space 26 intervening place. A gap is generated between the outer member 1 and the outer member 1 so that the sensor 21 can be easily installed in the vicinity of the notch 20 b without interfering with the outer member 1. Moreover, since the inner surface of the strain generating member 20 is a flat surface over the entire surface, the processing of the sensor unit 19 and the installation of the sensor 21 are facilitated. The bolt 23 is inserted into the bolt insertion hole 27 of the spacer 26 from the bolt insertion hole 22 that penetrates in the radial direction provided in the contact fixing portion 20 a of the strain generating member 20, and is provided on the outer peripheral portion of the outer member 1. The bolt hole 24 is screwed.

  If the inner surface of the strain generating member 20 is a flat surface, an insulating layer is formed on the sensor installation surface on the inner surface by printing and baking, and an electrode and a strain measurement resistor are printed on the insulating layer. By forming by baking, the sensor 21 can be easily formed on the inner surface of the strain generating member 20. When the sensor 21 is formed in this way, there is no decrease in the adhesive strength due to a change in diameter and the time when the sensor 21 is fixed to the sensor installation surface of the strain generating member 20, and the reliability of the sensor unit 19 can be improved. it can. Further, since the processing is easy, the cost can be reduced.

  11 and 12 show still another embodiment of the present invention. In this embodiment, the sensor-equipped wheel bearing shown in FIGS. 7 to 10 is replaced with a spacer 26 interposed between the strain generating member 20 of the sensor unit 19 and the outer diameter surface of the outer member 1. Thus, a groove 27 is provided between the fixing positions of the two contact fixing portions 20a of the strain generating member 20 on the outer diameter surface of the outer member 1. Other configurations are the same as those of the embodiment of FIGS.

  As described above, when the groove 27 is provided on the outer diameter surface of the outer member 1, the two contact fixing portions 20 a are directly fixed to the outer diameter surface of the outer member 1 with the entire inner surface of the strain generating member 20 as a flat surface. Even so, a gap is formed between the outer diameter surface of the outer member 1 and the inner side surface of the strain generating member 20, so that the sensor 21 does not interfere with the outer diameter surface of the outer member 1. Easy to install in the vicinity.

It is sectional drawing of the bearing for wheels with a sensor concerning one Embodiment of this invention. It is a front view of the outward member in the wheel bearing with a sensor. It is an expanded sectional view of the sensor unit installation part in FIG. (A) is a front view of one structural example of the sensor unit in the wheel bearing with the sensor, and (B) is a bottom view of the sensor unit. (A) is a front view of another configuration example of the sensor unit in the wheel bearing with sensor, and (B) is a bottom view of the sensor unit. It is a wave form diagram of the output signal of the sensor 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 a front view of the outward member in the wheel bearing with a sensor. It is an expanded sectional view of the sensor unit installation part in FIG. (A) is a front view of one structural example of the sensor unit in the wheel bearing with the sensor, and (B) is a bottom view of the sensor unit. It is sectional drawing of the bearing for wheels with a sensor concerning further another embodiment of this invention. It is an expanded sectional view of the sensor unit installation part in FIG. 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 1a ... Car body mounting flange 1aa ... Projection piece 2 ... Inner member 3, 4 ... Rolling surface 5 ... Rolling body 14 ... Bolt hole 16 for vehicle body mounting ... Knuckle 19 ... Sensor unit 20 ... Strain generation Member 20a ... Contact fixing part 20b ... Notch 21 ... Sensor 25 ... Estimating means 26 ... Spacer 27 ... Groove

Claims (13)

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,
Two contact fixing portions fixed to the outer diameter surface of the fixed side member of the outer member and the inner member in contact with the outer diameter surface, and a notch positioned between the two contact fixing portions. And at least one sensor unit having a sensor that is attached to the strain generating member and detects a strain of the strain generating member, and the two contact fixing portions of the sensor unit are connected to each other. The fixed side member is disposed at the same phase position in the circumferential direction, and one of the two contact fixing portions is an axial direction around the outboard side rolling surface of the double row rolling surface. The other one of the contact fixing portions is arranged on the outboard side further than the one contact fixing portion, and the notch portion of the sensor unit is outboard than the central position between the two contact fixing portions. This is located on the side Sensor equipped wheel support bearing assembly according to claim.   2. The sensor-equipped wheel bearing according to claim 1, wherein the notch portion of the sensor unit is further notched from the outer surface side to the inner surface side of the strain generating member.   The notch part of the sensor unit according to claim 2, wherein the notch part is notched in the width direction from both side surfaces in the width direction orthogonal to the direction in which the two contact fixing parts of the strain generating member are arranged. Bearing for wheel with sensor.   4. The wheel bearing with sensor according to claim 1, wherein the width dimension of the notch portion of the sensor unit is 2 mm or less. 5.   5. The strain generating member of the sensor unit according to claim 1, wherein the strain generating member is a maximum force assumed as an external force acting on the fixed side member or an acting force acting between the tire and the road surface. The sensor-equipped wheel bearing is characterized in that it is not plastically deformed even in a state in which is applied.   6. The sensor unit according to claim 1, wherein the sensor unit is provided with the sensor around a notch portion of the strain generating member, and the entire predetermined surface portion including the sensor installation surface of the strain generating member is provided. A wheel bearing with sensor, characterized by a flat surface.   7. The sensor according to claim 6, wherein an insulating layer is formed on the sensor installation surface of the strain generating member by printing and firing, and an electrode and a strain measurement resistor are formed on the insulating layer by printing and firing. Features wheel bearing with sensor.   8. The sensor-equipped wheel bearing according to claim 6, wherein the strain generating member of the sensor unit is fixed to an outer diameter surface of the stationary member via a spacer.   The sensor-equipped wheel bearing according to claim 6 or 7, 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.   In any one of Claims 1 thru | or 9, 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 part provided with each bolt hole protrudes to the outer diameter side than the other part, and the sensor unit is arranged at the center between the adjacent projecting pieces. Features wheel bearing with sensor.   11. The sensor-equipped wheel according to claim 1, wherein one of the sensor units 1 is provided on an upper surface portion of an outer diameter surface of the outer member with respect to a tire ground contact surface. Bearings.   12. The method according to claim 1, further comprising an estimation unit that estimates an external force acting on a wheel bearing or an acting force between a tire and a road surface based on an output signal of the sensor. Seisa wheel bearings. 13. The external force acting on the wheel bearing according to claim 12, wherein the estimation means uses at least one of an absolute value of the sensor signal, an average value of the output signal, and an amplitude of the output signal. Or the wheel bearing with a sensor characterized by estimating the action force between a tire and a road surface.

Images