JP2008175644A - Bearing for wheel with sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing for a wheel with a sensor capable of installing the sensor compactly, detecting a load with high sensitivity, and lowering cost in mass production. <P>SOLUTION: In the bearing for the wheel, a strain sensor 21 is mounted on a fixing side member, which is either of an outer member and an inner member. For example, it is assumed that the fixing side member is the outer member. The strain sensor 21 comprises a strain generating member 22 and sensor elements 23 mounted on the strain generating member 22. The strain generating member 22 has a first contact fixing part 22a facing to a flange surface provided on the outer member, and a second contact fixing part 22b facing to the peripheral surface of the outer member, and a connection part 22c for connecting both contact fixing parts 22a, 22b together comprises a bent part 22e which is bent in the middle toward the outer member side. A mounting spot of the sensor elements 23 on the strain generating member 22 is near the bent part 22e on the furthermore first contact fixing part 22a side than the bent part 22e of the connection part 22c. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

  2. Description of the Related Art Conventionally, there is a wheel bearing provided with a sensor for detecting the rotational speed of each wheel for safe driving of an automobile. Conventional measures to ensure driving safety of general automobiles are performed by detecting the rotational speed of the wheels of each part, but the rotational speed of the wheels is not sufficient, and it is further safer by using other sensor signals. It is required that the surface can be controlled.

  Therefore, it is conceivable to control the posture from the load acting on each wheel during vehicle travel. For example, a large load is applied to the outer wheel in cornering, and the load applied to each wheel is not uniform. In addition, even when the load is uneven, the load applied to each wheel is uneven. For this reason, if the load applied to the wheel can be detected at any time, the suspension control etc. is controlled in advance based on the detection result, thereby controlling the attitude during vehicle travel (preventing rolling during cornering, preventing the front wheel from sinking during braking, It is possible to prevent subsidence due to uneven load capacity. However, there is no appropriate installation location of a sensor that detects a load acting on the wheel, and it is difficult to realize posture control by load detection.

  In addition, when steer-by-wire is introduced in the future and the system becomes a system in which the axle and the steering are not mechanically coupled, it is required to detect the axle direction load and transmit the road surface information to the handle held by the driver.

As a response to such a demand, a wheel bearing has been proposed in which a strain gauge is attached to the outer ring of the wheel bearing to detect the strain (for example, Patent Document 1).
Special table 2003-530565 gazette

  The outer ring of the wheel bearing is a part that has a rolling surface and requires strength, and is a bearing part that is produced through complicated processes such as plastic working, turning, heat treatment, and grinding. When a strain gauge is attached to the outer ring as in Patent Document 1, there is a problem that productivity is poor and the cost for mass production is high. In addition, it is difficult to detect the distortion of the outer ring with high sensitivity, and when the detection result is used for attitude control during vehicle travel, the accuracy of control becomes a problem.

  Accordingly, it has been considered to provide a strain generating member fixed to the outer ring, and to attach a strain measuring sensor element to the strain generating member. With this configuration, the strain generating member to which the sensor element is attached may be fixed to the outer ring, and productivity is improved. However, it was still insufficient to detect the distortion of the outer ring with high sensitivity.

  An object of the present invention is to provide a sensor-equipped wheel bearing in which a load detection sensor can be compactly installed in a vehicle, the load applied to the wheel can be detected with high sensitivity, and the cost during mass production is low.

  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 facing the rolling surface of the outer member, In a wheel bearing having a double row rolling element interposed between both rolling surfaces and rotatably supporting the wheel with respect to the vehicle body, the wheel bearing is fixed to a fixed side member of the outer member and the inner member. A strain sensor comprising a strain generating member and a strain measuring sensor element attached to the strain generating member, and the strain generating member of the strain sensor is a flange provided on the fixed side member. A first contact fixing portion for a surface and a second contact fixing portion for a peripheral surface of the fixed side member, and the connecting portion connecting the both contact fixing portions is a direction in which a bent portion approaches the fixed side member. The sensor is bent in the middle A mounting portion to the strain generating member of the child, characterized in that the vicinity of the in the than the bent portion of the connecting portion first contact fixing portion and bent portion.

When a load is applied to the rotation-side member as the vehicle travels, the fixed-side member is deformed via the rolling elements, and the deformation causes distortion of the distortion generating member. The sensor element attached to the strain generating member outputs according to the strain of the strain generating member. The distortion of the fixing member can be detected from this output. If the relationship between strain and load is obtained in advance through experiments and simulations, the load applied to the wheel can be detected from the output of the sensor element. Moreover, this detected load can be used for vehicle control of an automobile.
Since the wheel bearing has a configuration in which a strain sensor including a strain generating member and a sensor element attached to the strain generating member is attached to the fixed side member, the load detecting sensor can be compactly installed in the vehicle. Since the strain generating member is a simple part that can be attached to the fixed member, attaching a sensor element to the member can provide excellent mass productivity and reduce costs.
The strain generating member has two contact fixing portions with respect to the fixed side member, and the first contact fixing portion of the contact fixing portions is a flange surface provided on the fixed side member. Since the contact fixing part is the peripheral surface of the fixed side member, the radial positions of the first and second contact fixing parts are different, and the distortion of the fixed side member is easily transferred and expanded on the distortion generating member. Become. Since the sensor element outputs in accordance with the transferred and enlarged distortion, the distortion of the fixed side member can be detected with high sensitivity, and the load measurement accuracy is increased.
In addition, the connecting portion of the strain generating member is bent at the middle portion in the direction in which the bent portion approaches the fixed side member, so that the distortion portion is particularly distorted near the bent portion on the first contact fixing portion side than the bent portion. Appears greatly. In particular, since the sensor element is attached at a position where the distortion appears to be large, the distortion of the stationary member can be detected with higher sensitivity.

The fixed member can be an outer member. In that case, the strain sensor is attached to the outer peripheral surface of the outer member. In this case, the connecting portion of the strain generating member can be formed in an L shape including a portion along the radial direction and a portion along the axial direction.
The portion along the radial direction of the connecting portion of the strain generating member is deformed according to the deformation of the flange of the outer member. Since the connecting portion is L-shaped, strain concentrates in the vicinity of the bent portion in the portion along the radial direction of the connecting portion, and a strain larger than that of the outer member appears. That is, the distortion generated in the vicinity of the bent portion in the portion along the radial direction of the connecting portion is obtained by transferring and expanding the distortion at the proximal end of the flange. Since the sensor element is mounted at a location where the distortion of the outer member appears after being transferred and enlarged, an output of the sensor element corresponding to the enlarged distortion of the outer member is obtained, and the output of the outer member is obtained from the output. Distortion can be detected with high sensitivity.

When the connecting portion of the strain generating member is L-shaped as described above, the attachment position of the sensor element to the strain generating member is changed from the bent portion of the connecting portion to the first contact fixing portion side. The position should be within 3 times the wall thickness.
The reason for this is that, as shown in the graph of FIG. 6, the magnitude x of distortion generated in the connecting portion of the strain generating member is the largest at the position t from the bent portion, where t is the thickness of the connecting portion, This is because if the distance is 3 t or more, a small value that is not suitable for the measurement of distortion is obtained.

In the present invention, a plurality of sensor elements may be arranged in the circumferential direction with respect to the strain generating member.
If a plurality of sensor elements are arranged side by side in the circumferential direction, distortion of the fixed side member can be detected using the average value of the output of each sensor element, so that the accuracy of detecting the distortion of the fixed side member is increased. Can do.

In the present invention, the first contact fixing portion in the strain generating member or the extension portion extending from the first contact fixing portion in the strain generating member to the side opposite to the second contact fixing portion. In addition, the same number of sensor elements as the sensor elements of the connection part are attached to the same number, and an amplifier circuit for outputting a new signal obtained by amplifying the output of the sensor element of the connection part from the output signals of the sensor elements of the connection part and the extension part May be provided.
The first contact fixing portion in the strain generating member and the extension portion provided to extend from the first contact fixing portion in the strain generating member to the opposite side of the second contact fixing portion are the distortion of the fixed side member. It is a place that is hardly affected. A bridge connection is made between the element of the first contact fixing part and the extension part which is hardly affected by the distortion of the fixed side member and the sensor element of the connecting part which is a part where the distortion of the fixed side member greatly appears. By configuring the amplifier circuit, it is possible to output a new signal obtained by amplifying the output of the sensor element at the connection portion. By using the amplified signal for detecting the distortion of the fixed side member, the distortion of the fixed side member can be detected with high sensitivity.

  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 facing the rolling surface of the outer member, In a wheel bearing having a double row rolling element interposed between both rolling surfaces and rotatably supporting the wheel with respect to the vehicle body, the wheel bearing is fixed to a fixed side member of the outer member and the inner member. A strain sensor comprising a strain generating member and a strain measuring sensor element attached to the strain generating member, and the strain generating member of the strain sensor is a flange provided on the fixed side member. A first contact fixing portion for a surface and a second contact fixing portion for a peripheral surface of the fixed side member, and the connecting portion connecting the both contact fixing portions is a direction in which a bent portion approaches the fixed side member. The sensor is bent in the middle Since the attachment position of the child to the member for generating distortion is located on the first contact fixing part side and in the vicinity of the bent part with respect to the bent part in the connecting part, a sensor for load detection is installed compactly in the vehicle. And the load applied to the wheel can be detected with high sensitivity. Since the strain generating member is a simple part that can be attached to the fixed member, attaching a sensor element to the member can provide excellent mass productivity and reduce costs.

  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.

  This sensor-equipped wheel bearing includes an outer member 1 having a double row rolling surface 3 formed on the inner periphery, an inner member 2 having a rolling surface 4 opposed to each of the rolling surfaces 3, and these It is comprised by the double row rolling element 5 interposed between the rolling surfaces 3 and 4 of the outer member 1 and the inner member 2. This wheel bearing is a double-row angular ball bearing type, and the rolling elements 5 are made of balls and are held by a cage 6 for each row. The rolling surfaces 3 and 4 are arc-shaped in cross section, and each rolling surface 3 and 4 is formed so that the contact angle is outward. Both ends of the bearing space between the outer member 1 and the inner member 2 are sealed by sealing devices 7 and 8, respectively.

The outer member 1 is a fixed side member, and has a flange 1a attached to the knuckle in the suspension device (not shown) of the vehicle body on the outer periphery, and the whole is an integral part. The flange 1a is provided with vehicle body mounting holes 14 at a plurality of locations in the circumferential direction.
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 brake component (not shown) protrudes toward the outboard side.

  A strain sensor 21 shown in FIG. 4 is provided on the outer peripheral portion of the outer member 1. The strain sensor 21 includes a strain generating member 22 fixed to the outer member 1 via a first mounting member 24 and a second mounting member 25, and strain measurement attached to the strain generating member 22. Sensor element 23 for use.

The strain generating member 22 includes a first contact fixing portion 22a that is contact-fixed to the flange 1a surface of the outer member 1 via the first mounting member 24, and an outer portion via the second mounting member 25. And the second contact fixing portion 22b fixed to the peripheral surface of the side member 1, and the connecting portion 22c connecting both the contact fixing portions 22a and 22b has a bent portion 22e on the outer member 1 side. It is said that it was bent in the middle in the direction of approach.
The strain generating member 22 of this embodiment is manufactured by, for example, pressing a plate material, and is formed into an L shape with a radial portion 22A along the radial direction and an axial portion 22B along the axial direction. It is configured in the shape of An intermediate portion of the radial portion 22A is a first contact fixing portion 22a, and an outboard side portion of the axial portion 22B is a second contact fixing portion 22b. The connecting portion 22c includes a portion 22ca along the radial direction and a portion 22cb along the axial direction, and has a shape bent at a right angle in the middle portion. Further, an extension 22d is provided on the outer diameter side of the first contact fixing portion 22a of the radial portion 22A. If the strain generating member 22 is a pressed product of a plate material, the strain generating member 22 can be easily manufactured, and the cost can be reduced.

Two sensor elements 23 are attached side by side in the circumferential direction in the vicinity of the bent portion 22e in the portion 22ca along the radial direction of the connecting portion 22c and in each of the extended portions 22d. These sensor elements 23 are fixed to the distortion generating member 22 using, for example, an adhesive.
The attachment location of the sensor element 23 (S1) of the connecting portion 22c is preferably a location where distortion appears greatly in the portion 22ca along the radial direction of the connecting portion 22c. Specifically, the position is within three times the wall thickness t of the connecting portion 22c from the bent portion 22e of the connecting portion 22c to the first contact fixing portion 22a side. That is, when the distance from the bent portion 22e to the attachment location of the sensor element 23 is x, the relationship x <3t is established. The reason for this is that, as shown in the graph of FIG. 6, the magnitude of the distortion generated in the connecting part 22c of the distortion generating member 22 is the largest at the position t from the bent part 22e, and is suitable for measuring distortion when separated by 3t or more. This is because there is no small value.
On the other hand, the other sensor element 23 (S2) is attached to the extension portion 22d as a portion that is hardly affected by the distortion of the outer member 1.

As shown in FIGS. 1 to 3, the strain sensor 21 is fixed to the outer member 1 using a bolt 76, and the first contact fixing portion 22 a and the first attachment of the strain generating member 22. Bolt insertion holes 70, 71 in the axial direction are formed in the member 24, and bolt insertion holes 72, 73 in the radial direction are formed in the second contact fixing portion 22 b of the distortion generating member 22 and the second mounting member 25. Are formed respectively. Further, a bolt screw hole 74 corresponding to the bolt insertion holes 70 and 71 in the axial direction is formed on the surface on the outboard side of the outer member flange 1 a, and the radial direction is formed on the outer peripheral surface of the outer member 1. Bolt screw holes 75 corresponding to the bolt insertion holes 72 and 73 are formed. The position of the bolt screw hole 74 is in the vicinity of the vehicle body mounting hole 14 on the flange 1a surface.
The strain sensor 21 inserts a bolt 76 from the outboard side into the bolt insertion hole 70 of the strain generating member 22 and the bolt insertion hole 71 of the first mounting member 24, and the male screw portion 76 a of the bolt 76 is connected to the outer member. The bolt 76 is screwed into the first bolt screw hole 74, and the bolt 76 is inserted from the outer peripheral side into the bolt insertion hole 72 of the strain generating member 22 and the bolt insertion hole 73 of the second mounting member 25. The external thread 1 is fixed to the outer member 1 by screwing the male screw portion 76 a into the bolt screw hole 75 of the outer member 1.

The fixing of the strain generating member 22 and the first and second mounting members 24 and 25 and the fixing of the first and second mounting members 24 and 25 and the outer member 1 may be performed by adhesive fixing with an adhesive. Moreover, you may use an adhesive agent and a bolt together. Further, the fixing may be performed by welding without using an adhesive or a bolt.
Regardless of which of these fixing structures is employed, the distortion generating member 22 and the first and second mounting members 24 and 25, and the first and second mounting members 24 and 25 and the outer member 1 are firmly secured. Can be fixed. Therefore, the distortion generating member 22 is not displaced with respect to the outer member 1, and the deformation of the outer member 1 can be accurately transmitted to the distortion generating member 22.

  As shown in FIG. 3, the strain sensor 21 includes the first and second contact fixing portions 22 a and 22 b of the strain generating member 22, so that both contact fixing portions 22 a and 22 b are in the circumferential direction of the outer member 1. It fixes to the outer peripheral part of the outer member 1 via the 1st, 2nd attachment members 24 and 25 so that it may become a position of the same phase. If the first and second contact fixing portions 22a and 22b are in the same phase in the circumferential direction, the length of the strain generating member 22 can be shortened, so that the strain sensor 21 can be easily installed.

  The strain generating member 22 has a shape or material that does not cause plastic deformation by being fixed to the outer member 1. Further, the strain generating member 22 needs to have a shape that does not cause plastic deformation even when the maximum expected load is applied to the wheel bearing. The above assumed maximum force is the maximum force assumed in traveling that does not lead to vehicle failure. This is because, when plastic deformation occurs in the strain generating member 22, the deformation of the outer member 1 is not accurately transmitted to the strain generating member 22 and affects the measurement of strain.

  Various sensors can be used as the sensor element 23. For example, when the sensor element 23 is composed of a metal foil strain gauge, in consideration of the durability of the metal foil strain gauge, even when the maximum expected load is applied to the wheel bearing, the strain generating member 22 is preferably 1500 microstrain or less. For the same reason, when the sensor element 23 is composed of a semiconductor strain gauge, the amount of strain is preferably 1000 microstrain or less. Moreover, when the sensor element 23 is comprised by the thick film type sensor, it is preferable that the distortion amount is 1500 microstrain or less.

  As shown in FIG. 1, as means for processing the output of each sensor element 23 of the strain sensor 21, an amplifier circuit 30, an acting force estimation means 31, and an abnormality determination means 32 are provided. As shown in FIG. 5, the amplifier circuit 30 includes two sensor elements 23 (S1) attached to the connecting portion 22c where the distortion of the outer member 1 appears to be large, and an extension portion that is hardly affected by the distortion of the outer member 1. The two sensor elements 23 (S2) attached to 23d are bridge-connected, and the intermediate terminal of the series circuit of one sensor element S1, S2 and the intermediate terminal of the series circuit of the other sensor elements S2, S1 are connected. The circuit is connected to the inverting input terminal and the non-inverting input terminal of the dynamic amplifier 31a, respectively, and acts to amplify the output of the sensor element 23 (S1) twice. The actions of the acting force estimating means 31 and the abnormality determining means 32 will be described later. These circuits and means 30, 31 and 32 may be provided in an electronic circuit device (not shown) on a circuit board or the like attached to the outer member 1 of the wheel bearing, or an automobile. It may be provided in the electric control unit (ECU).

  The operation of the sensor-equipped wheel bearing with the above configuration will be described. When a load is applied to the hub wheel 9, the outer member 1 is deformed via the rolling elements 5, and the deformation is transmitted to the strain generating member 22 attached to the outer member 1. Deform. Each sensor element 23 outputs according to the distortion of the distortion generating member 22. From the output of each sensor element 23, the output of the sensor element 23 (S1) is amplified by a factor of two from the amplifier circuit 30 and output. The distortion of the outer member 1 can be detected from the amplified output.

  The radial portion 22A of the strain generating member 22 is deformed according to the deformation of the flange 1a of the outer member 1. Since the strain generating member 22 is L-shaped, in the vicinity of the corner on the radial portion 22A side between the radial portion 22A and the axial portion 22B, that is, in the portion 22ca along the radial direction of the connecting portion 22c. Distortion concentrates in the vicinity of the bent portion 22e, and distortion larger than that of the outer member 1 appears there. That is, the distortion generated in the vicinity of the bent portion 22e in the portion 22ca along the radial direction of the connecting portion 22c is a transfer and expansion of the distortion of the R portion 1b at the base end of the flange 1a. Since the fixing part of the first contact fixing part 22a is in the vicinity of the vehicle body mounting hole 14 on the surface of the flange 1a, the difference in the radial position between the first and second contact fixing parts 22a and 22b should be as large as possible. Therefore, the distortion of the outer member 1 tends to appear after being transferred and enlarged on the distortion generating member 22.

  Since the strain changes depending on the direction and magnitude of the load, if the relationship between the strain and the load is obtained in advance through experiments and simulations, the external force acting on the wheel bearing or the acting force between the tire and the road surface is calculated. be able to. From the relationship between strain and load obtained and set in advance through experiments and simulations as described above, the acting force estimating means 31 is configured so that the external force acting on the wheel bearing or the distance between the tire and the road surface is determined by the output of the sensor element 23. Is calculated. The abnormality determining means 32 outputs an abnormality signal to the outside when it is determined that the external force acting on the wheel bearing calculated by the acting force estimating means 31 or the acting force between the tire and the road surface exceeds an allowable value. Output. This abnormal signal can be used for vehicle control of an automobile. In addition, when an external force acting on the wheel bearing in real time or an acting force between the tire and the road surface is output, finer vehicle control becomes possible.

  In this embodiment, the strain sensor 21 is provided at only one place on the outer member 1. However, for example, as shown in FIG. 7, the strain sensor 21 may be provided at two or more places. When the strain sensors 21 are provided at two or more locations, it becomes possible to detect a load with higher accuracy.

8 and 9 show different embodiments. In the strain sensor 21 of this embodiment, a sensor element 23 for measuring the strain of the strain generating member 22 is attached to a strain generating member 22 made of a machined product. The distortion generating member 22 includes a first contact fixing portion 22a that is fixed in contact with the outer member 1 in the vicinity of the vehicle body mounting hole 14, and a second contact fixing portion that is fixed in contact with the outer peripheral surface of the outer member 1. 22b, and are directly attached to the outer member 1 by these contact fixing portions 22a and 22b. In this embodiment, the adhesive is fixed by an adhesive.
The distortion generating member 22 includes a connecting portion 22c that connects the first contact fixing portion 22a and the second contact fixing portion 22b, and includes a portion 22ca along the radial direction and a portion 22cb along the axial direction. It is configured in an L shape. The thickness of the portion 22ca along the radial direction is reduced so as to be less rigid than the portion 22cb along the axial direction. One sensor element 23 is attached in the vicinity of the bent portion 22e in the portion 22ca along the radial direction of the connecting portion 22c. Similarly to the above, the mounting location of the sensor element 23 is also set to a position within three times the wall thickness t of the portion 22cb along the axial direction of the connecting portion 22c from the bent portion 22e of the connecting portion 22c (x <3t). ing.
The other configuration is the same as that of the above embodiment. The same reference numerals are given to the same components.

  Also in this embodiment, the distortion of the outer member 1 is transmitted to the distortion generating member 22, and the sensor element 23 outputs according to the distortion of the distortion generating member 22. At that time, the portion 22 ca along the radial direction of the connecting portion 22 c is deformed according to the deformation of the flange 1 a of the outer member 1. The connecting portion 22c of the strain generating member 22 is composed of a portion 22ca along the radial direction having a low rigidity and a portion 22ca along the radial direction having a low rigidity and a portion 22cb along the axial direction having a high rigidity. Therefore, the strain concentrates in the vicinity of the bent portion 22e in the portion 22ca along the radial direction, that is, the portion where the sensor element 23 is attached, and there is a strain larger than that of the outer member 1 there. appear. That is, the distortion generated at the location where the sensor element 23 is attached is a distortion obtained by transferring and expanding the distortion of the R portion 1b at the base end of the flange 1a. Since the sensor element 23 outputs in accordance with this strain, the strain of the outer member 1 can be detected with high sensitivity, and the strain measurement accuracy is increased.

  As for the strain generating member 22 made of a machined product used in this embodiment, sensor elements 23 may be attached to a plurality of locations in the circumferential direction of the connecting portion 22c as in the above embodiment. In addition to the sensor element 23 of the connecting portion 22c, the sensor element 23 is attached to a location where there is almost no influence of the distortion of the outer member 1, for example, the first contact fixing portion 22a. The output of the sensor element 23 of 22c may be amplified.

  In each of the above-described embodiments, the connecting portion 22c of the strain generating member 22 has an L-shape including a portion 22ca along the radial direction and a portion 22cb along the axial direction. There is no need to have an L-shape, and any bent portion may be used as long as the bent portion is bent in the middle in a direction approaching the outer member 1 side. In this case as well, the element sensor attached to the connecting portion is located closer to the first contact fixing portion than the bent portion in the connecting portion and in the vicinity of the bent portion.

In each of the above embodiments, the case where the outer member 1 is a fixed side member has been described. However, the present invention can also be applied to a wheel bearing in which the inner member is a fixed side member. The strain sensor 21 is provided on the peripheral surface that is the inner periphery of the inner member.
In each of the above embodiments, the case where the present invention is applied to a third generation type wheel bearing has been described. However, the present invention is for a first or second generation type wheel in which the bearing portion and the hub are independent parts. The present invention can also be applied to a bearing or a fourth-generation type wheel bearing in which a part of the inner member is composed of an outer ring of a constant velocity joint. Further, this sensor-equipped wheel bearing can be applied to a wheel bearing for a driven wheel, and can also be applied to a tapered roller type wheel bearing of each generation type.

It is a figure showing combining the sectional view of the wheel bearing with a sensor concerning the embodiment of this invention, and the block diagram of the conceptual composition of the detection system. It is the elements on larger scale of FIG. It is a front view which shows the outward member and distortion sensor of the wheel bearing with a sensor. (A) is a fractured side view of the strain sensor, (B) is a rear view thereof, and (C) is a perspective view thereof. It is a circuit diagram of an amplifier circuit. It is a graph which shows the relationship between the distance from the bending part of the connection part of the member for distortion generation, and the magnitude | size of distortion. It is a front view which shows the outward member and strain sensor of a different wheel bearing with a sensor. It is sectional drawing of the bearing for wheels with a sensor concerning different embodiment of this invention. (A) is a top view of the strain sensor of the wheel bearing with a sensor, (B) is the side view, (C) is the back view.

Explanation of symbols

1 ... Outer member (fixed side member)
1a ... Flange 2 ... Inward member (rotation side member)
3, 4 ... rolling surface 5 ... rolling elements 7, 8 ... sealing device 14 ... vehicle body mounting hole 21 ... strain sensor 22 ... strain generating member 22a ... first contact fixing portion 22b ... second contact fixing portion 22c ... Connection part 22ca ... part 22cb along the radial direction of the connection part ... part 22e along the axial direction of the connection part ... bent part 23 ... sensor element 30 ... amplification circuit

Claims (6)

An outer member in which a double row rolling surface is formed on the inner periphery, an inner member having a rolling surface opposite to the rolling surface of the outer member, and a double row interposed between both rolling surfaces In a wheel bearing for supporting a wheel rotatably with respect to the vehicle body,
A strain sensor comprising a strain generating member fixed to a fixed side member of the outer member and the inner member and a strain measuring sensor element attached to the strain generating member is provided. The distortion generating member has a first contact fixing portion for a flange surface provided on the fixed side member and a second contact fixing portion for a peripheral surface of the fixed side member, and both the contact fixing portions. The connecting portion that connects the bent portion is bent in the middle portion in a direction in which the bent portion approaches the fixed side member, and the attachment location of the sensor element to the member for generating distortion is more than the bent portion in the connecting portion. The wheel bearing with sensor is also characterized in that it is on the first contact fixing portion side and in the vicinity of the bent portion.   The sensor-equipped wheel bearing according to claim 1, wherein the fixed-side member is an outer member.   The sensor-equipped wheel bearing according to claim 2, wherein the connecting portion of the distortion generating member is formed in an L shape including a portion along the radial direction and a portion along the axial direction.   4. The sensor-equipped wheel according to claim 3, wherein the attachment position of the sensor element to the distortion generating member is a position within three times the thickness of the connecting portion from the bent portion of the connecting portion to the first contact fixing portion side. Bearings.   5. The wheel bearing with sensor according to claim 1, wherein a plurality of the sensor elements are arranged in the circumferential direction with respect to the member for generating distortion. 6.   6. The first contact fixing portion of the strain generating member according to claim 5, or an extension portion extending from the first contact fixing portion of the strain generating member to the opposite side of the second contact fixing portion. The same number of sensor elements as the sensor elements of the connection part are attached, and an amplifier circuit is provided for outputting a new signal obtained by amplifying the output of the sensor element of the connection part from the output signals of the sensor elements of the connection part and the extension part. Bearing for wheel with sensor.

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