JP5014107B2 - 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 strain on 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). Further, 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 Document 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, the deformation of the flange portion of the fixed ring involves slipping between the flange surface and the knuckle surface when the static frictional force is exceeded, so there is a problem that hysteresis occurs in the output signal when a repeated load is applied. Yes (detection resolution decreases when hysteresis occurs).
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 vertical load Fz acting on the wheel bearing, the amount of deformation of the fixed ring with respect to the load Fz is small, so the amount of distortion is also small. With the above technique, the detection sensitivity is low and the load Fz cannot be detected with high accuracy.

  Accordingly, the present inventors have developed a sensor-equipped wheel bearing having the following configuration in order to solve the above problems. The wheel bearing in this sensor-equipped wheel bearing includes an outer member in which double-row rolling surfaces are formed on the inner member, and an inner member in which a rolling surface facing the rolling surface is formed on the outer periphery. And a double-row rolling element interposed between the opposing rolling surfaces of both members, and supports the wheel rotatably with respect to the vehicle body. A sensor unit comprising a strain generating member and a strain measuring sensor attached to the strain generating member is provided on the outer diameter surface of the fixed member of the outer member and the inner member. The strain generating member has two contact fixing portions that are fixed in contact with the outer diameter surface of the fixed side member, and the two contact fixing portions are at the same position in the circumferential direction of the fixed side member and in the axial direction. It fixes to a stationary-side member so that it may become a separated position.

  However, in this configuration, the change in the output signal of the sensor is small with respect to the change in the load, and the detection error becomes large due to drift generated in the output signal due to temperature, noise, or the like. As a result, it is difficult to calculate the load in each direction in a state where a composite load (for example, the cornering force Fy and the vertical load Fz) is applied to the wheel bearing.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a wheel bearing with a sensor capable of accurately detecting any one of a vertical load applied to a wheel and a longitudinal load due to a driving force or a braking force and a cornering force without being affected by hysteresis. Is to provide.

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 At least one sensor unit pair comprising two sensor units arranged on the outer diameter surface of the fixed member is provided, and the sensor unit is fixed in contact with the outer diameter surface of the fixed side member and fixed at least two or more. A strain generating member having a portion and a sensor attached between two contact fixing portions of the strain generating member to detect strain of the strain generating member, and at least two contact fixing portions of the contact fixing portions are At the same axial position of the fixed side member One sensor unit in the pair of sensor units has a sensor for determining a direction in which a cornering force is applied to a wheel bearing, and the sensor unit is disposed so as to be spaced apart from each other in the circumferential direction. An estimation means for estimating a load acting on the wheel bearing from an output signal of the sensor of the unit pair is provided.
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, the two contact fixing portions of the strain generating member in the two sensor units of the sensor unit pair are fixed at the same axial position on the outer diameter surface of the outer member and at positions spaced apart from each other in the circumferential direction. Since a sensor for detecting the strain of the strain generating member is attached between the two contact fixing portions, the strain of the outer member is concentrated and transmitted to the strain generating member, and the strain is highly sensitive by the sensor. The hysteresis generated in the output signal is also reduced. Thus, the estimation means accurately determines the absolute value of the cornering force acting on the wheel bearing and at least one of the vertical load and the front-rear load serving as the driving force and the braking force from the sensor output signal. Can be estimated. Further, since one sensor unit has a sensor for determining the application direction of the cornering force acting on the wheel bearing, the estimation means can also determine the application direction of the cornering force from the output signal of this sensor. it can. As a result, it is possible to accurately estimate the cornering force acting on the wheel bearing and at least one of the vertical load and the front-rear load serving as the driving force and the braking force.

  In the present invention, in the sensor unit having a sensor for determining the application direction of the cornering force in the sensor unit pair, the distortion generating member has at least three or more contact fixing portions, and at least two or more of them are in contact. The fixing portion is arranged so as to be in the same axial direction position of the fixing side member and spaced apart from each other in the circumferential direction, and at least one contact fixing portion is connected to the contact fixing portion of the fixing side member. A sensor mounted between two contact fixing parts spaced apart in the axial direction at positions that are in the same phase in the circumferential direction and spaced apart from each other in the axial direction can also be used for determining the direction in which the cornering force is applied. good.

In the present invention, the two sensor units of the sensor unit pair are arranged on the upper surface portion and the lower surface portion of the outer diameter surface of the fixed side member that are vertically positioned with respect to the tire ground contact surface, and the estimation means includes cornering The force and the vertical load may be estimated.
For the vertical load, the upper and lower surfaces of the fixed member are deformed. In this configuration, the cornering force and the vertical load are applied under any load condition without being affected by hysteresis. It can be detected accurately.

In the present invention, the two sensor units of the sensor unit pair are arranged on the right surface portion and the left surface portion of the outer diameter surface of the fixed side member that are in the front-rear position with respect to the tire ground contact surface, and the estimation means includes cornering It is good also as what estimates the load in the front-back direction used as force, driving force, and braking force.
For the load that becomes the driving force, the right and left surfaces of the fixed side member are deformed. In this configuration, the cornering force and the driving force are not affected by hysteresis and under any load condition. It is possible to accurately detect the load in the front-rear direction as a braking force.

  In this invention, two pairs of the sensor unit pairs are provided, and the two sensor units of the pair of sensor units are arranged such that the upper surface portion and the lower surface portion of the outer diameter surface of the fixed-side member that are vertically positioned with respect to the tire ground contact surface And the two sensor units of the other pair of sensor units are arranged on the right surface portion and the left surface portion of the outer diameter surface of the fixed side member which are front and rear positions with respect to the tire ground contact surface, The estimation means may estimate the cornering force, the load in the vertical direction, and the load in the front-rear direction as the driving force or the braking force. In this configuration, it is possible to accurately detect the cornering force, the load in the vertical direction, the front-rear load as the driving force, and the braking force under any load condition without being affected by hysteresis.

  In this invention, the distortion generating member of the two sensor units of the sensor unit pair may have a notch, and the sensor may be provided around the notch. In the case of this configuration, the strain transmitted from the fixed member to the strain generating member is easily concentrated on the notch, the detection sensitivity of the sensor is improved, and the load can be detected with high accuracy.

In this invention, the estimation means may calculate the load by at least one of an absolute value, an average value, and an amplitude of the output signal of the sensor.
During the rotation of the wheel bearing, the amplitude of the output signal of the sensor of the sensor unit may periodically change 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, the passing speed of the rolling element, that is, the rotation speed of the wheel can be detected. Thus, when the output signal varies, the load can be calculated from the average value or amplitude of the output signal. When there is no fluctuation, the load can be calculated from the absolute value.

  In this invention, the sensor is formed by printing and firing an insulating layer on the sensor installation surface of the strain generating member, and forming an electrode and a strain measuring resistor on the insulating layer by printing and firing. May be. 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 strain generating member may be provided with temperature detecting means.

In this invention, you may provide the signal processing circuit part which processes the output signal of the said sensor in the said distortion generation member.
When the strain generating member is provided with a sensor other than the strain detection sensor, the strain detection sensor and the other sensor can be connected via the signal processing circuit unit, so that wiring between the sensors becomes unnecessary. .

  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 At least one pair of sensor units each including two sensor units arranged at a position forming a phase difference of 180 degrees in the circumferential direction of the fixed side member is provided on the outer diameter surface of the fixed side member. A strain generating member having at least two contact fixing portions fixed in contact with the outer diameter surface of the member, and a sensor which is attached between the two contact fixing portions of the strain generating member and detects strain of the strain generating member Of the contact fixing part At least two contact fixing portions are arranged so as to be in the same phase position in the circumferential direction of the fixed side member and at positions spaced apart from each other in the axial direction, and one sensor unit in the sensor unit pair includes a wheel There is a sensor for judging the direction of application of the cornering force acting on the bearing for the vehicle, and there is provided an estimation means for estimating the load acting on the wheel bearing from the output signal of the sensor of the sensor unit pair. Without receiving, it is possible to accurately detect either the vertical load applied to the wheel, the longitudinal load due to the driving force or the braking force, and the cornering force.

  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, and the rolling elements 5 are formed 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-fit holes 15 for hub bolts (not shown) at a plurality of locations in the circumferential direction. In the vicinity of the base of the hub flange 9a of the hub wheel 9, a cylindrical pilot portion 13 for guiding a wheel and a brake 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 20A and 20B is provided on the outer diameter surface of the outer member 1 that is a fixed member. These two sensor units 20 </ b> A and 20 </ b> B are arranged at a position that forms 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, by providing the two sensor units 20A and 20B constituting the sensor unit pair 19 at two locations on the outer diameter surface of the outer member 1 that are in the vertical position with respect to the tire ground contact surface, the upper surface portion and the lower surface portion. The vertical load Fz that is the vertical load acting on the wheel bearing and the cornering force Fy that is the axial load are detected. Specifically, as shown in FIG. 2, one sensor unit 20 </ b> A 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 Another sensor unit 20B is arranged at the center between two adjacent projecting pieces 1aa on the lower surface of the outer diameter surface.

  For example, the sensor unit 20A disposed on the upper surface portion of the outer diameter surface of the outer member 1 includes a strain generating member 21 and the strain generating member as shown in FIGS. 3 and 4 in an enlarged plan view and an enlarged sectional view. And two or more (two in this case) sensors 22A and 22B which are attached to 21 and detect the strain of the strain generating member 21. The strain generating member 21 is made of an elastically deformable metal thin plate material such as a steel material, and has an L-shaped plan shape. The strain generating member 21 has three or more (three in this case) contact fixing portions 21 a, 21 b, and 21 c that are fixed to the outer diameter surface of the outer member 1 through spacers 23. These three contact fixing portions 21 a to 21 c are arranged at one end, corner, and other end of the L-shaped strain generating member 21.

  In the sensor unit 20A, the two contact fixing portions 21a and 21b of the strain generating member 21 are positioned at the same dimension in the axial direction of the outer member 1, and both the contact fixing portions 21a and 21b are circumferentially connected to each other. It is arranged so that it comes to a distant position. With this arrangement, one of the contact fixing portions 21a and 21b and the other remaining contact fixing portion 21c are in the same phase position in the circumferential direction of the outer member 1, and Both contact fixing portions 21b and 21c are arranged to be separated from each other in the axial direction. Further, notch portions 21d are formed on both side portions of the strain generating member 21 at the intermediate positions of the contact fixing portions 21a and 21b and both side portions of the intermediate positions of the contact fixing portions 21b and 21c. One sensor 22A in the sensor unit 20A is affixed to a location sandwiched between two notches 21d at an intermediate position between the two contact fixing portions 21a and 21b on the outer surface side of the strain generating member 21. The other one sensor 22B is affixed to a location sandwiched between two notches 21d at an intermediate position between the two contact fixing portions 21b and 21c on the outer surface side of the strain generating member 21. Thereby, one sensor 22A detects the distortion in the circumferential direction of the strain generating member 21, and the other one sensor 22B detects the strain in the axial direction of the strain generating member 21. Specifically, the detection signal of the sensor 22A is used to detect the absolute value of the cornering force Fy acting on the wheel bearing and the vertical load Fz. The detection signal of the other sensor 22B is used to determine the application direction of the cornering force Fy. Note that the strain generating member 21 is plastically deformed even in a state in which an assumed maximum force is applied as an external force acting on the outer member 1 that is a fixed member or an acting force acting between the tire and the road surface. It is desirable not to do so. This is because, when plastic deformation occurs, the deformation of the outer member 1 is not transmitted to the sensor unit 20A and affects the measurement of strain.

  Each contact fixing portion 21 a to 21 c of the strain generating member 21 is fixed to the outer diameter surface of the outer member 1 by a bolt 24 via a spacer 23. Each bolt 24 is inserted into a bolt insertion hole 26 of the spacer 23 from a bolt insertion hole 25 provided in each of the contact fixing portions 21 a to 21 c in the radial direction, and is provided in an outer peripheral portion of the outer member 1. 27. Thus, by fixing the contact fixing portions 21 a to 21 c to the outer diameter surface of the outer member 1 through the spacer 23, the sensor installation portion of the strain generating member 21 is separated from the outer diameter surface of the outer member 1. It becomes a state, and distortion deformation around the sensor installation part becomes easy. As the axial position where the contact fixing portions 21a and 21b are arranged, 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. Another contact fixing portion 21c is arranged at a position closer to the outboard side than this position. 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 20A to the outer diameter surface of the outer member 1, a flat portion 1b is formed at a location where the spacer 23 is contacted and fixed on the outer diameter surface of the outer member 1.

  Although the sensor unit 20B disposed on the lower surface portion of the outer diameter surface of the outer member 1 is not described in detail, for example, the sensor unit 20A does not have the sensor 22B. In this case, the distortion generating member 11 may not have the one piece portion on which the contact fixing portion 21c is arranged. Other configurations are the same as those of the sensor unit 20A.

  Various sensors can be used as the sensors 22A and 22B. For example, the sensors 22A and 22B can be configured with a metal foil strain gauge. In that case, the distortion generating member 21 is usually fixed by adhesion.

  Also, the sensors 22A and 22B can be formed on the strain generating member 21 with a thick film resistor. FIG. 5 shows the structure of the sensor units 20A and 20B in that case. In the sensor units 20A, 20B, an insulating layer 50 is formed on the sensor mounting surface 21A of the strain generating member 21, and a pair of electrodes 51, 51 are formed on both sides of the surface of the insulating layer 50. 51, a strain measuring resistor 52 serving as a sensor is formed on the insulating layer 50, and a protective film 53 is formed on the electrodes 51 and 51 and the strain measuring resistor 52. Yes.

  A method for manufacturing the sensor units 20A and 20B will be described below. First, the insulating layer 50 is formed by printing and baking an insulating material such as glass on the surface of the strain generating member 21 formed of a metal material such as stainless steel. Next, a conductive material is printed and baked on the surface of the insulating layer 50 to form the electrodes 51 and 51. Further, a material for forming a resistor is printed and baked between the electrodes 51 and 51 to form a strain occurrence measuring resistor 52. Further, a protective film 53 is formed to protect the electrodes 51 and 51 and the strain measuring resistor 52.

  When the sensors 22A and 22B are formed in this way, there is no decrease in adhesive strength due to secular change as in the case where the sensor is installed on the sensor installation surface of the strain generating member 21, and the reliability of the sensor units 20A and 20B is improved. Can be made. Further, since the processing is easy, the cost can be reduced.

  Further, in the formation of the sensors 22A and 22B, the resistor generation circuit 52 and the resistor and the circuit constituting the bridge circuit may be formed by pattern printing and baking. In this case, variation in resistance of the bridge circuit can be reduced.

  The sensors 22A and 22B of the sensor units 20A and 20B are connected to the estimation means 30. The estimation means 30 is a means for estimating a load acting on the wheel bearing based on output signals of the sensors 22A and 22B of the sensor unit pair 19. Here, the estimation means 30 estimates the vertical load Fz and the cornering force Fy acting on the wheel bearing.

  Here, the sensor 22A is provided at an intermediate position between the two contact fixing portions 21a and 21b of the strain generating member 21 in the sensor units 20A and 20B, that is, the same axial direction position on the outer diameter surface of the outer member 1 and the circumference. The circumferential distortion is detected by a sensor 22A provided at an intermediate position between the two contact fixing portions 21a and 21b that are spaced apart from each other in the direction. Therefore, the estimation means 30 estimates the vertical load Fz and the cornering force (absolute value) Fy from the difference between the output signals of the two sensors 22A of the sensor unit pair 19. Thereby, even when there is a drift due to temperature or noise in the output signal of each sensor 22A, the influence of the drift can be canceled or reduced.

  The estimation means 30 is a relationship setting means (relationship setting means (vertical load Fz and strain amount (difference), cornering force Fy and strain amount (difference)) set in advance by experiment or analysis, using an arithmetic expression or a table. (Not shown). Thereby, the estimation means 30 can estimate the vertical load Fz and the cornering force (absolute value) Fy from the difference between the input output signals of the two sensors 22A using the relationship setting means.

Further, the estimating means 30 determines the direction of the cornering force Fy as follows.
For example, in the axial position of the contact fixing portion 22b of the strain generating member 21 in the sensor unit 20A shown in FIG. 3, the radial displacement ly of the strain generating member 21 from the position y1 to the position y2 is as shown in FIG. . As shown in the figure, the position that is most displaced in the radial direction differs depending on the direction of the cornering force Fy. Further, as shown in FIG. 7, the radial displacement amount at the position y2 monotonously increases / decreases as the applied cornering force Fy increases / decreases. As a result, the amount of strain at the intermediate position between the two contact fixing portions 21b and 21c arranged in the axial direction of the strain generating member 21 in the sensor unit 20A also increases or decreases according to the directionality of the cornering force Fy as shown in FIG. Therefore, the estimation means 30 determines the direction in which the cornering force Fy is applied from the magnitude of the output signal of the sensor 22B installed at the intermediate position between the two contact fixing portions 21b and 21c of the strain generating member 21 in the sensor unit 20A. can do. The magnitude of the output signal of the sensor 22B increases and decreases as the vertical load Fz increases and decreases as shown in FIG. Therefore, the estimation means 30 corrects the output signal of the sensor 22B with the previously estimated vertical load Fz to determine the application direction of the cornering force Fy.

  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. Here, the two contact fixing portions 21a and 21b of the strain generating member 21 in the two sensor units 20A and 20B of the pair of sensor units 19 are in the same axial direction position on the outer diameter surface of the outer member 1 and in the circumferential direction. Since the sensor 22A is fixed between the two contact fixing portions 21a and 21b and is detected between the two contact fixing portions 21a and 21b, the strain of the outer member 1 is concentrated on the strain generating member 21. The distortion is detected by the sensor 22A with high sensitivity, and the hysteresis generated in the output signal is also reduced. As a result, the estimation means 30 determines from the output signal of the sensor 22A either the cornering force Fy (absolute value) acting on the wheel bearing and at least one of the vertical load Fz and the longitudinal load Fx serving as a driving force or a braking force. It is possible to accurately estimate the load (in this case, the vertical load Fz). Further, since one sensor unit 20A has a sensor 22B for determining the application direction of the cornering force Fy acting on the wheel bearing, the estimation means 30 applies the application direction of the cornering force Fy from the output signal of the sensor 22B. Can also be determined. As a result, the cornering force and the vertical load Fz acting on the wheel bearing can be accurately estimated.

  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 this embodiment, among the two sensor units 20A and 20B constituting the sensor unit pair 19, in the sensor unit 20A having the sensor 22B for determining the application direction of the cornering force Fy, the distortion generating member 21 is At least three or more (here, three) contact fixing portions 21a to 21c are provided, and two of the contact fixing portions 21a and 21b are located at the same axial position on the outer diameter surface of the outer member 1 and in the circumferential direction. The sensor 22A, which is disposed so as to be spaced apart from each other and attached between the two contact fixing portions 21a and 21b, is used for estimating the cornering force (absolute value) Fy and the vertical load Fz. The other contact fixing portion 21c is arranged so as to be in the same phase in the circumferential direction as the contact fixing portion 21b and spaced apart from each other in the axial direction, and in the same direction in the circumferential direction. The sensor 22B mounted between the two contact fixing portions 21b and 21c at the position is used for determining the application direction of the cornering force Fy. Therefore, in order to determine the application direction of the cornering force Fy, it is not necessary to provide it separately from the sensor units 20A and 20B, and the configuration becomes simple.

  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 20A and 20B of the sensor unit pair 19 are Since they are arranged on the upper surface and the lower surface of the outer diameter surface of the outer member 1 that is positioned up and down with respect to the tire ground contact surface, the output signals of these sensors 22A and 22B can be obtained under any load conditions. The estimation means 30 can accurately estimate the cornering force (absolute value and application direction) Fy and the vertical load Fz.

  The two sensor units 20A and 20B that form the sensor unit pair 19 are arranged on the upper surface portion and the lower surface portion of the outer diameter surface of the outer member 1 that is in the vertical position with respect to the tire ground contact surface as in this embodiment. You may arrange | position not only to a case but to the right surface part and left surface part of the outer-diameter surface of the outer member 1 used as the front-back position with respect to a tire ground-contact surface. With respect to the longitudinal load Fx caused by the driving force and the braking force, the right surface portion and the left surface portion of the outer member 1 which is a fixed member are deformed. In this case, from the output signals of these sensors 22A and 22B The estimation means 30 can accurately estimate the cornering force (absolute value and application direction) Fy and the front / rear load Fx caused by the driving force or the braking force.

  The strain generating member 21 of the sensor units 20A, 20 may be provided with at least one of temperature detection means such as a thermistor and a platinum resistance element, and sensors such as vibration and acceleration. Thus, by integrating other sensors with the strain sensor, the number of parts can be reduced.

  In this embodiment, the distortion generating member 21 of the two sensor units 20A and 20B of the sensor unit pair 19 has a notch 21d, and the sensors 22A and 22B are provided around the notch 21d. The strain transmitted from the outer member 1 which is the fixed member to the strain generating member 21 is easily concentrated on the notch 21d, the detection sensitivity by the sensors 22A and 22B is improved, and the load is accurately applied. Can be detected.

  Further, in this embodiment, as shown in FIG. 2, one sensor unit 20A is arranged at the center between two adjacent protruding pieces 1aa on the upper surface portion of the outer diameter surface of the outer member 1, and the outer member Since one other sensor unit 20B is disposed at the center between two adjacent projecting pieces 1aa on the lower surface portion of the outer diameter surface of one, the deformation of the projecting piece 1aa causes the knuckle 16 (FIG. 1) to The influence of hysteresis occurring between them can be reduced accordingly.

  In this embodiment, for example, an axial position around the rolling surface 3 of the outboard side row of the outer member 1 is selected as the axial position where the contact fixing portions 21a and 21b in the sensor unit 20A are arranged. Since the other contact fixing portion 21c is arranged at a position on the outboard side from this position, the load received by the outer member 1 from the rolling element 5 can be accurately measured. Moreover, since the radial deformation of the outer member 1 is large in the periphery between the rolling surfaces 3 and 3, the load can be estimated with high sensitivity.

  Further, during the rotation of the wheel bearing, the amplitude of the output signal of the sensor unit 20A, 20B is shown in FIG. 9 depending on the presence or absence of the rolling element 5 passing through the vicinity of the sensor unit 20A, 20B on the rolling surface 3. A periodic change may occur as shown in the waveform diagram. This is because the amount of deformation differs between when the rolling element 5 passes and when it does not, and the amplitude of the output signals of the sensors 22A and 222B has a peak value for each passing period of the rolling element 5. Therefore, by measuring the period of the peak value in the output signal by the estimating means 30, it is possible to detect the passing speed of the rolling element 5, that is, the rotational speed of the wheel. When the output signal varies as described above, the estimation unit 30 can calculate the difference between the two sensors 22A of the sensor unit pair 19 from the average value and amplitude of each output signal. When there is no change, it can be calculated from the absolute value.

  Another embodiment of the present invention is shown in FIGS. In the wheel bearing with sensor of this embodiment, in the embodiment shown in FIGS. 1 to 9, as shown in FIG. 12 showing an enlarged plan view and a sectional view of the sensor unit 20 </ b> A, on the outer diameter surface of the outer member 1. Two intermediate portions where the two contact fixing portions 21a and 21b arranged in the circumferential direction of the strain generating member 21 are fixed, and two intermediate portions where the two contact fixing portions 21b and 21c arranged in the axial direction are fixed. In addition, by providing the grooves 1 c, the spacer 23 is omitted, and the installation portions of the sensors 22 A and 22 B in the strain generating member 21 are separated from the outer diameter surface of the outer member 1. The same applies to the sensor unit 20B. Other configurations are the same as those of the embodiment shown in FIGS. 10 and 11, the estimation means 30 is omitted.

  FIG. 14: shows the front view which looked at the outer member 1 of the bearing for wheels with a sensor in other embodiment of this invention from the outboard side. In this embodiment, another sensor unit pair 19A is provided in the embodiment of FIGS. The sensor unit pair 19A is also composed of two sensor units 20C and 20D arranged at a position that forms a phase difference of 180 degrees in the circumferential direction of the outer diameter surface of the outer member 1 that is a fixed member. In this case, the two sensor units 20C and 20D are disposed on the right surface portion and the left surface portion of the outer diameter surface of the outer member 1 which are front and rear positions with respect to the tire ground contact surface. The configuration of the sensor units 20C and 20B is the same as that of the sensor units 20A and 20B in the embodiment of FIGS. The sensors 22A and 22B of these two sensor units 20C and 20D are also connected to the estimation means 30. Other configurations are the same as those of the embodiment of FIGS.

  By arranging the two sensor units 20C and 20D of the sensor unit pair 19A as described above, it is possible to detect the front / rear load Fx as a driving force or a braking force. The estimation means 30 estimates the front / rear load Fx, which is a driving force or a braking force, from the difference between the output signals of the sensors 22A of the sensor units 20C and 20D. For the load Fx, the left surface portion and the right surface portion of the outer member 1 are deformed, so that the load Fx can be accurately estimated under any load condition.

  FIG. 15 shows an enlarged plan view of another configuration example of the sensor unit 20A in the embodiment of FIGS. In this sensor unit 20A, the contact fixing portion 21a and the contact fixing portion 21c of the strain generating member 21 are connected by an L-shaped extension portion 21e, so that the planar shape of the strain generating member 21 is an approximate square shape. A signal processing circuit 31 for processing the output signals of the sensors 22A and 22B is provided on the L-shaped extension 21e. As described above, by providing the signal writing circuit unit 31 on the strain generating member 21, for example, when another sensor is installed on the strain generating member 21, wiring between circuit units of other sensors is unnecessary. Become.

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 a figure which combines and shows the front view of the outward member of the wheel bearing with a sensor, and the block diagram of a conceptual structure of a detection system. 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 an expanded sectional view of other examples of a sensor unit. It is a graph which shows the relationship between the deformation amount in the outer-diameter surface of an outer member, and cornering force. It is a graph which shows the relationship between the amount of deformation | transformation in the outer-diameter surface of an outer member, and cornering force by using the variation | change_quantity of the vertical direction load Fz as a parameter. It is a graph which shows the relationship between the deformation | transformation amount and cornering force in the installation part of the direction determination sensor in a distortion generation member by using the variation | change_quantity of the vertical direction load Fz as a parameter. It is a wave form diagram of an output signal of a sensor unit in a bearing for wheels with a sensor. It is a figure showing combining the sectional view of the wheel bearing with a sensor concerning other embodiments of this invention, and the block diagram of the conceptual composition of the detection system. It is a front view of the outward member of the wheel bearing with a sensor. It is an enlarged plan view of a sensor unit in the wheel bearing with sensor. It is XI-XI arrow sectional drawing in FIG. It is a front view of the outward member of the bearing for wheels with a sensor concerning further another embodiment of this invention. It is an enlarged plan view of another example of the sensor unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Outer member 2 ... Inner member 3, 4 ... Rolling surface 5 ... Rolling element 19, 19A ... Sensor unit pair 20A, 20B ... Sensor unit 21 ... Strain generating member 21a-21c ... Contact fixing | fixed part 21d ... Notch Units 22A, 22B ... sensor 30 ... estimating means 31 ... signal processing circuit unit

Claims (10)

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,
Among the outer member and the inner member, at least one pair of sensor units including two sensor units arranged on the outer diameter surface of the fixed side member is provided, and the sensor unit is an outer diameter surface of the fixed side member. A strain generating member having at least two or more contact fixing parts fixed in contact with the sensor, and a sensor mounted between the two contact fixing parts of the strain generating member for detecting the strain of the strain generating member, Among the contact fixing parts, at least two contact fixing parts are arranged so as to be in the same axial direction position of the fixed side member and spaced apart from each other in the circumferential direction, and one sensor unit in the sensor unit pair is: A sensor for determining a direction in which a cornering force acting on the wheel bearing is applied, and a load acting on the wheel bearing from an output signal of the sensor of the sensor unit pair; Bearing sensor wheeled characterized by comprising estimation means for estimating.   The sensor unit having a sensor for determining a direction in which a cornering force is applied in the pair of sensor units according to claim 1, the distortion generating member has at least three contact fixing portions, and at least two of them are fixed. The contact fixing portion is disposed so as to be in the same axial direction position of the fixed side member and spaced apart from each other in the circumferential direction, and at least one contact fixing portion is disposed on the contact fixing portion of the fixed side member. And a sensor mounted between two contact fixing parts spaced apart in the axial direction at positions that are in the same phase in the circumferential direction and spaced apart from each other in the axial direction. Bearing for sensor wheel.   In Claim 1 or Claim 2, two sensor units of the pair of sensor units are arranged on the upper surface portion and the lower surface portion of the outer diameter surface of the fixed side member that is in the vertical position with respect to the tire ground contact surface, The estimation means is a wheel bearing with a sensor that estimates a cornering force and a load in a vertical direction.   In Claim 1 or Claim 2, the two sensor units of the pair of sensor units are arranged on the right surface portion and the left surface portion of the outer diameter surface of the fixed side member that are in the front-rear position with respect to the tire ground contact surface, The estimating means is a wheel bearing with a sensor that estimates a longitudinal load caused by a cornering force, a driving force, and a braking force.   In Claim 1 or Claim 2, two pairs of said sensor unit pairs are provided, and two sensor units of one pair of sensor units are arranged on the outer diameter surface of said fixed side member that is in the vertical position with respect to the tire ground contact surface. The two sensor units of the other pair of sensor units are arranged on the upper surface portion and the lower surface portion, and the right surface portion and the left surface portion of the outer diameter surface of the fixed side member that are in the front-rear position with respect to the tire ground contact surface, The sensor-equipped wheel bearing is configured to estimate a cornering force, a load in the vertical direction, and a load in the front-rear direction as a driving force or a braking force.   6. The sensor according to claim 1, wherein the strain generating member of the two sensor units of the sensor unit pair has a notch, and the sensor is provided around the notch. Wheel bearing.   7. The method according to claim 1, wherein the estimating unit calculates the load by at least one of an absolute value, an average value, and an amplitude of the output signal of the sensor. Wheel bearing with sensor.   8. The sensor according to claim 1, wherein the sensor is formed by printing and baking an insulating layer on a sensor installation surface of the strain generating member, and an electrode and a strain measuring resistor on the insulating layer. A wheel bearing with sensor, which is formed by printing and firing.   9. The wheel bearing with sensor according to claim 1, wherein a temperature detecting means is provided on the strain generating member.   The sensor-equipped wheel bearing according to any one of claims 1 to 9, wherein the distortion generating member is provided with a signal processing circuit unit for processing an output signal of the sensor.

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