JP5349022B2 - 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 technology for detecting the load applied to each wheel of an automobile, a sensor-equipped wheel bearing has been proposed in which a strain sensor is provided on the outer diameter surface of the flange portion of the outer ring, which is a fixed ring of the wheel bearing, and the load is detected. (For example, Patent Document 1). Further, as shown in FIG. 19, a wheel bearing has been proposed in which a strain gauge 51 is attached to the outer ring 50 of the wheel bearing to detect the strain (for example, Patent Document 2).

  Further, a sensor unit comprising a strain generating member and a strain sensor attached to the strain generating member is attached to an inner diameter surface of an outer member that is a fixed ring of a bearing, and the strain generating member is at least 2 with respect to the outer member. There has been proposed a sensor-equipped wheel bearing having a contact fixing portion at one location, a notch portion at least at one location between adjacent contact fixing portions, and the strain sensor being disposed in the notch portion ( For example, Patent Document 3).

According to the sensor-equipped wheel bearing disclosed in Patent Document 3, when a load is applied to the rotating wheel as the vehicle travels, the fixed wheel is deformed via the rolling elements, and this deformation causes distortion of the sensor unit. The strain sensor provided in the sensor unit detects the strain of the sensor unit. If the relationship between strain and load is obtained in advance through experiments and simulations, the load applied to the wheel can be detected from the output of the strain sensor.
JP 2002-098138 A Special table 2003-530565 gazette JP 2007-57299 A

However, the techniques disclosed in Patent Documents 1 to 3 described above do not have a specific description of sensor wiring. For example, in a wheel bearing with a sensor in which a sensor unit is attached to an outer member of a wheel bearing as disclosed in Patent Document 3, there are a plurality of sensor units or a signal processing for processing a sensor output signal of the sensor unit. When the IC is also attached to the outer member, each of the sensor unit and signal processing IC is attached to the outer member, and then the signal cables for taking out the processed sensor output signals outside the bearing are individually wired. There's a problem.
(1) The number of parts increases, resulting in an increase in cost and weight reduction.
(2) It takes time for wiring work, and this also raises the cost.
(3) Wrong wiring or damaged electronic components during wiring deteriorates the yield, which also increases costs.
In the wheel bearing with sensor disclosed in Patent Document 3, since the sensor unit is attached to the inner diameter surface of the outer member, wiring becomes more difficult.

  The object of the present invention is to prevent the failure of electronic parts such as sensors due to the influence of the external environment by simple wiring processing, and to detect the load acting on the wheel bearing and the tire ground contact surface accurately and inexpensively. It is to provide a wheel bearing with a high sensor.

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 having a double row rolling element interposed between opposing rolling surfaces of the member and rotatably supporting the wheel with respect to the vehicle body, the fixed side portion of the outer member and the inner member. A plurality of sensor units comprising a strain generating member fixed in contact with a peripheral surface of the outer member, and a sensor attached to the strain generating member and detecting a strain of the strain generating member; A signal processing IC for processing the output signal, a signal cable for extracting the processed output signal to the outside of the bearing, and a wiring circuit for wiring between the sensor unit, the signal processing IC and the signal cable. strip off Rekishiburu based on that An electronic component including bets, and an annular sensor assembly disposed along the outer diameter side groove provided on the outer peripheral surface of the protective cover of the annular This sensor assembly on the peripheral surface of the outer member only attached to the outer member concentric, an opening is provided at a plurality of locations in the circumferential direction of the protective cover, the sensor units are arranged located on the inner diameter side of each of these openings, the circumferential direction of the respective openings A half portion of the flexible substrate is a wide portion, and a connection portion with the sensor unit on the flexible substrate is arranged corresponding to the wide portion .

When a load acts between the wheel bearing or the tire of the wheel and the road surface, the load is also applied to the outer member, which is a stationary member of the wheel bearing, causing deformation. Since the strain generating member in the sensor unit is fixed in contact with the outer member, is transmitted distortion of the outer member is enlarged in the strain generating member, the strain is detected sensitively by a sensor, the hysteresis occurring in the output signal And the load can be estimated accurately.
In particular, a plurality of sensor units, a signal processing IC that processes the output signals of the sensors of the sensor unit, a signal cable that takes out the processed output signals to the outside of the bearing, the sensor unit, the signal processing IC, and the An electronic component including a flexible substrate having a wiring circuit for wiring between signal cables is arranged inside an annular protective cover to form an annular sensor assembly, and the sensor assembly is arranged around the outer member . Since it is mounted concentrically with the outer member on the surface, it is possible to prevent the failure of electronic components such as sensors due to the influence of the external environment by simple wiring processing, and the load acting on the wheel bearing and tire contact surface can be accurately measured. Can be detected. For example, electronic components such as sensors, signal processing ICs, signal cables and the like can be reliably held from stepping stones, muddy water, salt water, and the like from the outside.
In addition, since the wiring circuit of the flexible substrate is wired between the sensor unit, the signal processing IC, and the signal cable, the number of parts can be reduced, and the cost and weight can be reduced. In addition, since the wiring can be automated, it is possible to reduce the number of wiring steps and the damage of electronic components due to incorrect wiring or wiring.
Moreover, since the flexible substrate can be bent, the sensor assembly can be attached along the peripheral surface of the outer member of the assembled bearing even after the electronic component is unitized. That is, since it is not necessary to assemble the bearing after the sensor assembly is mounted in a state where the outer member is a single member , existing production equipment can be used for the production of the sensor-equipped wheel bearing. As a result, an inexpensive and highly reliable wheel bearing with sensor can be obtained.

  In the present invention, the flexible substrate may be provided with a circuit pattern for connection and wiring with the sensor unit, the signal processing IC, and the signal cable. By providing the circuit pattern in this way, it is possible to further reduce the man-hours for wiring and reduce damage to electronic components due to incorrect wiring or wiring.

  In the present invention, the signal processing IC may be directly attached to the flexible substrate, or the signal cable may be directly connected to a wiring circuit of the flexible substrate. That is, you may perform attachment and a connection without an inclusion. Moreover, you may attach the said sensor unit directly to a flexible substrate. In this configuration, all the electronic components of the sensor assembly and the flexible substrate can be integrated into a unit.

  In this invention, you may attach the said sensor unit to a flexible substrate so that the circuit printed surface may face the printed surface of the wiring circuit of the said flexible substrate. In the case of this configuration, the contact surface of the sensor unit with the fixed side member is a flat surface without a circuit printing surface or a solder portion, and the sensor unit can be attached to the fixed side member in close contact.

  In the present invention, the sensor unit may be separated from the flexible substrate except for a connection portion with the wiring circuit of the flexible substrate. In the case of this configuration, even if the sensor unit after wiring is attached to the fixed member, the sensor unit is less likely to be distorted by the bending force of the flexible substrate. Thereby, the initial offset at the time of sensor attachment is relieved and load detection with high accuracy becomes possible.

  In this invention, the base material of the flexible substrate may be polyimide. When the base material of the flexible substrate is polyimide, the flexible substrate can have sufficient flexibility and heat resistance.

In the present invention, the sensor assembly may be attached to the outer diameter surface of the outer member .

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 having a double row rolling element interposed between opposing rolling surfaces of the member and rotatably supporting the wheel with respect to the vehicle body, the fixed side portion of the outer member and the inner member. A plurality of sensor units comprising a strain generating member fixed in contact with a peripheral surface of the outer member, and a sensor attached to the strain generating member and detecting a strain of the strain generating member; A signal processing IC for processing the output signal, a signal cable for extracting the processed output signal to the outside of the bearing, and a wiring circuit for wiring between the sensor unit, the signal processing IC and the signal cable. strip off Rekishiburu based on that An electronic component including bets, and an annular sensor assembly disposed along the outer diameter side groove provided on the outer peripheral surface of the protective cover of the annular This sensor assembly on the peripheral surface of the outer member only attached to the outer member concentric, an opening is provided at a plurality of locations in the circumferential direction of the protective cover, the sensor units are arranged located on the inner diameter side of each of these openings, the circumferential direction of the respective openings The connection part with the sensor unit in the flexible board is arranged corresponding to the wide part, and the failure of electronic parts such as sensors due to the influence of the external environment is prevented by simple wiring processing. Thus, it is possible to provide an inexpensive and highly reliable wheel bearing with a sensor that can accurately detect a load acting on a wheel bearing or a tire ground contact surface.

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

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

The outer member 1 is a fixed side member, and has a vehicle body mounting flange 1a attached to a knuckle (not shown) in the suspension device of the vehicle body on the outer periphery, and the whole is an integral part. The vehicle body mounting flange 1a is provided with knuckle mounting screw holes 14 at a plurality of locations in the circumferential direction, and knuckle bolts (not shown) inserted into the knuckle bolt insertion holes from the inboard side are screwed into the screw holes 14. By doing so, the flange 1a is attached to a knuckle.
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 16 for hub bolts 15 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.

  Four sensor units 20 are provided on the outer diameter surface of the outer member 1 which is a fixed member. Here, these sensor units 20 are provided on the upper surface portion, the lower surface portion, the right surface portion, and the left surface portion of the outer diameter surface of the outer member 1 that is in the vertical position and the front-rear position with respect to the tire ground contact surface.

As shown in FIG. 11, these sensor units 20 include a strain generating member 21 and a strain sensor 22 that is attached to the strain generating member 21 and detects the strain of the strain generating member 21. The strain generating member 21 is made of an elastically deformable metal such as a steel material and is made of a thin plate material having a thickness of 2 mm or less. Further, the strain sensor 22 is affixed to a location where the strain increases with respect to the load in each direction on the strain generating member 21. Here, the central part sandwiched between the notch portions 21a on both sides is selected on the outer surface side of the strain generating member 21, and the strain sensor 22 detects the strain in the circumferential direction around the notch portion 21a. To do. Insertion holes 24 for bolts 23 (FIG. 2) for fixing the sensor unit 20 to the outer diameter surface of the outer member 1 are provided at two positions of the strain generating member 21 that are separated in the longitudinal direction across the strain sensor 22. It has been.
Note that the strain generating member 21 is plastically deformed even in a state in which an assumed maximum force is applied as an external force acting on the outer member 1 that is a fixed member or an acting force acting between the tire and the road surface. It is desirable not to do so. This is because when the plastic deformation occurs, the deformation of the outer member 1 is not transmitted to the sensor unit 20 and affects the measurement of strain.

  The four sensor units 20 include a signal processing IC 25 that is an integrated circuit chip that processes output signals from these strain sensors 22, and a signal cable wiring portion 26A that extracts the processed output signals to the outside of the bearing (FIG. 11). 9A and 9B together with electronic components such as a flexible substrate 35 having a wiring circuit 36 for wiring between the sensor unit 20, the signal processing IC 25, and the signal cable wiring portion 26A. An annular sensor assembly 28 shown in front and side views in FIGS. 15A and 15B is configured inside the annular protective cover 27 shown in the figure.

11A and 11B are a plan development view and a cross-sectional view of the electronic component disposed inside the protective cover 27. FIG. In this arrangement example of the electronic components, the wiring circuit 36 and the signal cable wiring portion 26A for wiring between each sensor unit 20, the signal processing IC 25, and the signal cable wiring portion 26A are printed as a circuit pattern on the belt-like flexible substrate 35. The signal processing IC 25 is directly mounted on the flexible substrate 35. The sensor unit 20 and the signal processing IC 25 are connected to the wiring circuit 36, and the lead-out portion 26B of the signal cable to the vehicle body side is connected to the signal cable wiring portion 26A by soldering or the like. Each sensor unit 20 is separated from the flexible substrate 35 except for a connection portion between the flexible substrate 35 and the wiring circuit 36.
In addition, the flexible substrate 35 has a wide portion as the mounting portion of the signal processing IC 25 and a narrow portion as the other portion, and each sensor unit 20 is arranged on the side of the narrow portion of the flexible substrate 35, so that The arrangement configuration is not widened. Thereby, the sensor assembly 28 can be configured compactly. In the sensor unit 20, the surface of the distortion generating member 21 opposite to the contact surface with the outer member 1 is a circuit printed surface, and this circuit printed surface faces the printed surface of the wiring circuit 36 of the flexible substrate 35. It attaches to the flexible substrate 35 so that it may become. Thereby, the contact surface of the sensor unit 20 with the outer member 1 becomes a flat surface without a circuit printing surface or a solder portion, and the sensor unit 20 can be attached to the outer member 1 in close contact.

  The flexible substrate 35 is disposed in the circumferential direction along the outer diameter side groove 29 </ b> A of the protective cover 27. As described above, polyimide is desirable as the base material of the flexible substrate 35 in order to place the flexible substrate 35 along the outer diameter side groove portion 29 </ b> A of the annular protective cover 27. When the base material of the flexible substrate 35 is polyimide, the flexible substrate 35 can have sufficient flexibility and heat resistance, and can be easily along the circumferential direction of the protective cover 27. The signal cable lead-out portion 26 </ b> B is drawn out from one place of the protective cover 27 to the outside of the protective cover 27. The material of the protective cover 27 may be plastic or rubber, or may be made of metal.

As shown in FIGS. 10 (A) and 10 (B) showing the Xa-Xa arrow sectional view and the Xb-Xb arrow sectional view of FIGS. Four places serving as arrangement portions of the sensor units 20 in the direction are flat flat portions 27a. An outer diameter side groove portion 29A extending along the circumferential direction is provided on the outer diameter surface of the protective cover 27, and the four flat portions 27a are provided in the radial direction from the outer diameter side groove portion 29A to the inner diameter surface. An opening 30 is provided through each of the openings 30. These openings 30 are in substantially rectangular extending in the circumferential direction of the protective cover 27, the halves are the wider portion 30 b. On both side edges along the circumferential direction on the inner diameter side of these openings 30, planar engagement step portions 30 a with which the strain generating members 21 of the sensor unit 20 are engaged are provided. Thereby, as shown in FIGS. 16A and 16B showing the XVIa-XVIa arrow sectional view and the XVIb-XVIb arrow sectional view of FIGS. 15A and 15B, the opening 30 of the protective cover 27. Further, each sensor unit 20 is installed with its distortion generating member 21 exposed to the inner diameter side.

  Since there is a step between the flexible substrate 35 arranged in the outer diameter side groove 29A of the protective cover 27 and the sensor unit 20 arranged on the inner diameter side of the protective cover 27, there is a difference between the sensor unit 20 and the flexible substrate 35. The connecting portion is bent into an S-shaped cross section as shown in FIG. Since the sensor unit 20 is separated from the flexible substrate 35 except for the connection portion of the flexible substrate 35 to the wiring circuit 36, the sensor unit 20 after wiring is attached to the outer diameter surface of the outer member 1 which is a fixed member. However, the sensor unit 20 is less likely to be distorted by the bending force of the flexible substrate 35. Thereby, the initial offset at the time of sensor attachment is relieved and load detection with high accuracy becomes possible.

Further, in the arrangement of the sensor unit 20 on the inner diameter side of the protective cover 27, as shown in FIG. 15B , the wide width portion 30b of the opening 30 of the protective cover 27 is connected to the sensor unit 20 in the flexible substrate 35. Connections are made to correspond. Thereby, the connection part with the sensor unit 20 of the flexible substrate 35 can be bent easily.

FIG. 12A shows a plan development view of another arrangement example of the electronic component arranged inside the protective cover 27, and FIG. 12B is a cross-sectional view taken along the line XIIb-XIIb in FIG. Indicates. In this example of electronic component arrangement, the sensor unit 20, the signal processing IC 25, and the signal cable wiring portion 26A are all mounted on the flexible substrate 35. Also in this case, in the sensor unit 20, the surface of the distortion generating member 21 opposite to the contact surface with the outer member 1 is a circuit printing surface, and this circuit printing surface is printed on the wiring circuit 36 of the flexible substrate 35. It is attached to the flexible substrate 35 so as to face the surface. In this example, strip-shaped openings 35 a extending in the longitudinal direction of the flexible substrate 35 are formed in portions corresponding to both side portions of the sensor unit 20 in the arrangement portion of the sensor unit 20 of the flexible substrate 35. In addition, the flexible substrate 35 is formed with insertion holes 35b of the bolts 23 at portions facing the insertion holes 24 of the bolts 23 (FIG. 2) that fix the sensor unit 20 to the outer diameter surface of the outer member 1. Yes.
As described above, by forming the band-shaped openings 35a in the portions of the flexible substrate 35 corresponding to the both sides of the sensor unit 20 in the arrangement portion of the sensor unit 20, the deformation of the strain generating member 21 in the sensor unit 20 can be changed. The load detection accuracy can be improved accordingly.
Other configurations are the same as those in the arrangement example shown in FIG.

FIGS. 13A and 13B are a plan development view and a cross-sectional view of still another example of the arrangement of the electronic components arranged inside the protective cover 27. FIG. Also in this electronic component arrangement example, the sensor unit 20, the signal processing IC 25, and the signal cable wiring portion 26A are all mounted on the flexible substrate 35. Also in this case, in the sensor unit 20, the surface of the distortion generating member 21 opposite to the contact surface with the outer member 1 is a circuit printing surface, and this circuit printing surface is printed on the wiring circuit 36 of the flexible substrate 35. It is attached to the flexible substrate 35 so as to face the surface. In this example, a rectangular opening 35 c is formed in the arrangement portion of the sensor unit 20 on the flexible substrate 35 so that substantially the entire sensor unit 20 is exposed.
As described above, by forming the square opening 35 c in which the entire sensor unit 20 is exposed in the arrangement portion of the sensor unit 20 in the flexible substrate 35, the deformation of the strain generating member 21 in the sensor unit 20 is caused by the flexible substrate 35. It can be surely prevented from being restricted, and the load detection accuracy can be improved accordingly.
Other configurations are the same as those in the arrangement example shown in FIG.

  14A and 14B are a plan development view and a cross-sectional view of still another example of the arrangement of the electronic components arranged inside the protective cover 27. FIG. In the example of the arrangement of the electronic components, each sensor unit 20 is separated from the flexible substrate 35 except for the connection portion with the wiring circuit 36 of the flexible substrate 35 as in the case of the arrangement example of FIG. In this arrangement example, the flexible substrate 35 is formed in a strip shape having the same width, and each sensor unit 20 is disposed along one side of the flexible substrate 35 along the flexible substrate 35. Other configurations are the same as those in the arrangement example shown in FIG.

The annular sensor assembly 28 is mounted concentrically with the outer member 1 on the outer diameter surface of the outer member 1 which is a fixed member of the bearing via a seal member 40. 5A and 5B show a front view and a side view of the seal member 40. FIG. As shown in FIGS. 6A and 6B showing the VIa-VIa arrow cross-sectional view and the VIb-VIb arrow cross-sectional view of FIGS. It consists of a ring-shaped metal core 41 along the inner diameter surface and a pair of ring-shaped elastic bodies 42 joined to the entire circumference of both side edges of the metal core 41 from the inner diameter surface to the outer diameter surface. The placement portion and each position facing the circumferential direction of the sensor unit 20 in the sensor assembly 28 of the seal member 40, the sensor unit exposure opening 43 that penetrates in a radial direction that have been found respectively. Thus, the sensor unit 20 is attached to the outer diameter of the outer member 1 from the sensor unit exposure opening 43 of the seal member 40 in a state where the sensor assembly 28 is attached to the outer diameter surface of the outer member 1 via the seal member 40. The surface can be contacted.

  The metal core 41 of the seal member 40 is made of a press-formed product of corrosion-resistant steel, and both side edges to which the ring-shaped elastic body 42 is joined are enlarged as shown in FIG. 6B, for example, as shown in FIG. The chamfered portion 41a has an inner diameter surface that changes in diameter toward the inner side in the width direction and an outer diameter surface that changes in diameter toward the inner side in the width direction. With such a joining structure, the ring-shaped elastic body 42 can be easily and reliably joined to both side edges of the cored bar 41 without using an adhesive or the like. Prior to the annular sensor assembly 28, the seal member 40 is press-fitted and fixed to the outer diameter surface of the outer member 1 in a single state before being assembled into a bearing.

  Further, on both side portions of the inner diameter surface of the protective cover 27 of the annular sensor assembly 28, an inner diameter side groove portion 29B that is in close contact with the ring-shaped elastic body 42 of the seal member 40 is formed as shown in FIGS. Has been. The annular sensor assembly 28 can be divided into two at the center as shown in FIGS. Specifically, an annular protective cover 27 is formed by connecting one end of each of the two divided bodies 27 </ b> A and 27 </ b> B with a hinge 31 so that the two half arcs of the sensor assembly 28 can be opened via the hinge 31. The part can be opened and closed. The maximum value of the opening dimension W in the open state of the sensor assembly 28 is based on the outer diameter dimension of the outer member 1 (more specifically, the outer diameter dimension when the seal member 40 is press-fitted and fitted). It has also been made larger. Thus, after the seal member 40 is press-fitted into the outer diameter surface of the outer member 1, the sensor assembly 28 is opened to a state where the opening dimension W is maximized, thereby overlapping the seal member 40. Can be installed.

  As shown in FIG. 8, a cylindrical grinding surface 1b is provided at the axial position of the outer diameter surface of the outer member 1 where the sensor assembly 28 is attached. In addition, four portions of the cylindrical grinding surface 1b with which the strain generating member 21 of the sensor unit 20 comes into contact, that is, an upper surface portion, a lower surface portion, a right surface portion, and a left surface portion are formed as a surface grinding surface portion 1c. Thereby, the distortion generating member 21 of each sensor unit 20 can be reliably brought into contact with the surface grinding surface portion 1c. Further, each surface grinding surface portion 1c is provided with a screw hole 32 that matches the bolt insertion hole 24 of the strain generating member 21. Thus, after the sensor assembly 28 is assembled to the cylindrical grinding surface 1b via the seal member 40, the bolt 23 inserted into the bolt insertion hole 24 (FIG. 11) of the strain generating member 21 as shown in FIG. By screwing into the screw hole 32, the sensor unit 20 is directly fixed to the outer diameter surface of the outer member 1, and at the same time, the entire sensor assembly 28 is also fixed. The assembly of the sensor assembly 28 is performed on the outer member 1 with the bearing assembled. An intermediate portion sandwiched between the two screw holes 32 in the surface grinding surface portion 1c is provided with a groove 1d extending in the axial direction. Thereby, since the intermediate site | part in which the notch part 21a in the distortion generation member 21 is located is separated from the surface grinding surface part 1c, distortion deformation of the periphery of the notch part 21a becomes easy. The four sensor units 20 are provided at positions where the respective strain sensors 22 have the same dimensions with respect to the axial direction of the outer member 1.

  3 and 4 are enlarged views of the sensor assembly 28 mounting portion of the outer member 1 in FIG. As shown in the figure, after the sensor assembly 28 is attached to the outer diameter surface of the outer member 1 in the state assembled to the bearing via the seal member 40, the electronic components (sensor unit 20, The exposed portions of the signal processing IC 25, the signal cable wiring portion 26 </ b> A, and the flexible substrate 35) from the protective cover 27 are sealed by secondary molding with the molding material 33. Specifically, the outer diameter side groove 29A of the protective cover 27 is filled with the molding material 33 over the entire circumference, and the exposed portion of the electronic component is sealed. 3 shows an enlarged cross-sectional view of a portion that is not connected to the wiring circuit 36 of the flexible substrate 35 of the sensor unit 20 in the circumferential direction, and FIG. 4 is an enlarged cross-sectional view of the wiring circuit 36 and the connection portion of the flexible substrate 35 of the sensor unit 20. The figure is shown.

  Instead of using the molding material 33 to seal the exposed part of the electronic component, the outer diameter side groove 29A of the protective cover 27 is filled with an adhesive or a sealing agent, and then the outer diameter surface of the sensor assembly 28 is filled. In addition, a ring-shaped outer cover 34 composed of two divided bodies 34A and 34B as shown in FIGS. 18A and 18B may be bonded and fixed as shown by phantom lines in FIGS.

  Various strain sensors 22 can be used. For example, the strain sensor 22 can be composed of a metal foil strain gauge. In that case, the distortion generating member 21 is usually fixed by adhesion. The strain sensor 22 can also be formed on the strain generating member 21 with a thick film resistor.

  The strain sensor 22 of the sensor unit 20 is connected to the signal processing IC 25. The signal processing IC 25 receives the force (vertical load Fz, load Fx serving as driving force, axial load Fy) acting between the wheel bearing and the wheel and the road surface (tire contact surface) according to the output signal of the strain sensor 22. The estimation means is an estimation means, and includes a signal processing circuit, a correction circuit, and the like. The signal processing IC 25 has relationship setting means (not shown) in which the relationship between the acting force and the output signal of the strain sensor 22 is set by an arithmetic expression or a table, and the relationship setting is performed from the input output signal. The value of the acting force is output using the means. The setting contents of the relationship setting means are obtained by a test or simulation in advance.

  When a load acts between the tire of the wheel and the road surface, the load is also applied to the outer member 1 that is a stationary member of the wheel bearing, causing deformation. Since the strain generating member 21 in the sensor unit 20 is fixed in contact with the peripheral surface of the outer member 1, the strain of the outer member 1 is enlarged and transmitted to the strain generating member 21, and the strain is transmitted to the strain sensor 22. And the hysteresis generated in the output signal is reduced, and the load can be estimated with high accuracy. Also, a plurality of sensor units 20, a signal processing IC 25 for processing the output signals of the strain sensors 22, a signal cable wiring portion 26A for taking out the processed output signals to the outside of the bearing, the sensor units 20, and the signals An electronic component including the processing IC 25 and the flexible substrate 35 having the wiring circuit 36 for wiring between the signal cable wiring portion 26A is disposed inside the annular protective cover 27 to form an annular sensor assembly 28. Since the sensor assembly 28 is attached to the peripheral surface of the outer member 1 concentrically with the outer member 1, the load acting on the wheel bearing and the ground contact surface of the tire can be accurately detected.

  In particular, a plurality of sensor units 20, a signal processing IC 25 that processes sensor output signals of the sensor unit 20, a signal cable wiring portion 26A that extracts the processed sensor output signals to the outside of the bearing, the sensor unit 20, An electronic component including a signal processing IC 25 and a flexible substrate 35 having a wiring circuit 36 for wiring between the signal cable wiring portion 26A is arranged inside an annular protective cover 27 to form an annular sensor assembly 28. Since the sensor assembly 28 is mounted concentrically with the outer member 1 on the outer diameter surface of the outer member 1 which is a fixed member, an electronic component including the sensor unit 20 can be obtained by a simple wiring process depending on the external environment Can be prevented (damage due to stepping stones, corrosion due to muddy water, salt water, etc.) And it prevents failure of the electronic components such as sensors, the load acting on the ground contact surface of the wheel support bearing assembly or the tire can be accurately detected over a long period.

Further, since the wiring circuit 36 of the flexible substrate 35 is wired between the sensor unit 20, the signal processing IC 25, and the signal cable wiring portion 26A, the number of parts is reduced, and the cost and the weight can be reduced. In addition, since the wiring can be automated, it is possible to reduce the number of wiring steps and the damage of electronic components due to incorrect wiring or wiring.
In addition, since the flexible substrate 35 is bendable, the sensor assembly 28 is attached along the outer diameter surface of the outer member 1 that is a stationary member of the assembled bearing even after the electronic component is unitized. Can do. That is, since it is not necessary to assemble the bearing after the sensor assembly 28 is mounted with the outer member 1 as a single unit, existing production equipment can be used for the production of the sensor-equipped wheel bearing. As a result, an inexpensive and highly reliable wheel bearing with sensor can be obtained.

In the above description, the case where the acting force between the wheel tire and the road surface is detected is shown. However, not only the acting force between the wheel tire and the road surface but also the force acting on the wheel bearing (for example, the preload amount) is detected. May be.
By using the detected load obtained from the sensor-equipped wheel bearing for vehicle control, it is possible to contribute to stable running of the automobile. In addition, when this sensor-equipped wheel bearing is used, a load sensor can be installed in a compact vehicle, the mass productivity can be improved, and the cost can be reduced.

  In this embodiment, the sensor unit 20 is attached to the flexible substrate 35 so that the circuit printed surface thereof faces the printed surface of the wiring circuit 36 of the flexible substrate 35. The contact surface with a certain outer member 1 does not have a stepped portion such as a circuit printing surface or a solder portion, and can be attached in close contact with the external member 1.

  In this embodiment, since the sensor assembly 28 can be divided into two at the center, it is easy to attach the outer member 1 which is a fixed member to the peripheral surface, and the assemblability is improved.

  In this embodiment, since the base material of the flexible substrate 35 is polyimide, the flexible substrate 35 can be provided with sufficient flexibility and heat resistance.

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

It is sectional drawing of the bearing for wheels with a sensor concerning one Embodiment of this invention. It is II-II arrow sectional drawing in FIG. It is an expanded sectional view of the part except the connection part of the sensor unit and the wiring circuit of a flexible substrate in the axial direction position in which the sensor assembly of an outer member is installed. It is an expanded sectional view of the connection part of the sensor unit and the wiring circuit of a flexible substrate in the axial direction position where the sensor assembly of an outer member is installed. (A) is a front view of a sealing member, (B) is the side view. (A) is VIa-V1a arrow sectional drawing in FIG. 5 (B), (B) is VIb-V1b arrow sectional drawing in FIG. 5 (A). It is a partial expanded sectional view of an example of a sealing member. It is a side view of an outward member. (A) is a front view of an annular | circular shaped protective cover, (B) is the same side view. (A) is Xa-Xa arrow sectional drawing in FIG.9 (B), (B) is Xb-Xb arrow sectional drawing in FIG.9 (A). (A) is an expansion | deployment top view of an example of arrangement | positioning of the electronic component installed in a sensor assembly, (B) is the same sectional drawing. (A) is an expanded top view of the other example of arrangement | positioning of the electronic component installed in a sensor assembly, (B) is XIIb-XIIb arrow sectional drawing of (A). (A) is a development top view of the further another example of arrangement | positioning of the electronic component installed in a sensor assembly, (B) is the same sectional drawing. (A) is a development top view of the further another example of arrangement | positioning of the electronic component installed in a sensor assembly, (B) is the same sectional drawing. (A) is a front view of the sensor assembly, and (B) is a side view of the sensor assembly. 15A is a cross-sectional view taken along the arrow XIVa-XIVa in FIG. 15B, and FIG. 15B is a cross-sectional view taken along the arrow XIVb-XIVb in FIG. (A) is a front view which shows the closed state of a sensor assembly, (B) is a front view which shows the open state of the sensor assembly. (A) is a side view of a split body of the ring-shaped outer cover, and (B) is a front view of the ring-shaped outer cover. It is a perspective view of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Outer member 2 ... Inner member 3, 4 ... Rolling surface 5 ... Rolling body 20 ... Sensor unit 21 ... Strain generating member 22 ... Strain sensor 25 ... Signal processing IC
26A ... Signal cable wiring portion 26B ... Signal cable lead-out portion 27 ... Protective cover 28 ... Sensor assembly 35 ... Flexible substrate 36 ... Wiring circuit

Claims (9)

An outer member having a double row rolling surface formed on the inner periphery, an inner member having a rolling surface facing the rolling surface formed on the outer periphery, and interposed between the opposing rolling surfaces of both members A double row rolling element, and a wheel bearing for rotatably supporting the wheel with respect to the vehicle body,
Distortion of the outer member and the inner strain generating member fixed in contact with the peripheral surface of the outer member is fixed side member of the member, and attached to the strain generating member the strain generating member A plurality of sensor units comprising sensors for detecting the signal, a signal processing IC for processing the output signal of the sensor, a signal cable for taking out the processed output signal to the outside of the bearing, the sensor unit, and the signal processing IC and an electronic component comprising a strip of full Rekishiburu substrate that having a wiring circuit for wiring between the signal cable, and arranged along the outer diameter side groove provided on the outer peripheral surface of the protective cover of the annular circle the annular sensor assembly, only mounting the sensor assembly to the outer member concentric to the circumferential surface of the outer member, an opening is provided at a plurality of locations in the circumferential direction of the protective cover, the inner diameter of each opening Located arranging the respective sensor units, characterized in that the half of the circumferential direction of the respective openings and the wide portion, were placed the connection portion of the sensor unit in the flexible substrate so as to correspond to the wide portion Bearing with sensor wheel. Oite to claim 1, the flexible substrate, the sensor unit, signal processing IC, and The signal cables and connections and sensor equipped wheel support bearing assembly provided with the circuit pattern of the wiring. The sensor-equipped wheel bearing according to claim 1 or 2 , wherein the signal processing IC is directly attached to the flexible substrate. 4. The wheel bearing with sensor according to claim 1 , wherein the signal cable is directly connected to a wiring circuit of the flexible substrate. 5. 5. The wheel bearing with sensor according to claim 1 , wherein the sensor unit is directly attached to the flexible substrate. 6. 6. The sensor-equipped wheel bearing according to claim 5 , wherein the sensor unit is attached to the flexible substrate so that a circuit printed surface thereof faces a printed surface of the wiring circuit of the flexible substrate. The sensor-equipped wheel bearing according to any one of claims 1 to 5 , wherein the sensor unit is separated from the flexible substrate except for a connection portion with the wiring circuit of the flexible substrate. 8. The sensor-equipped wheel bearing according to claim 1 , wherein the base material of the flexible substrate is polyimide. 9. The wheel bearing with sensor according to claim 1 , wherein the sensor assembly is attached to an outer diameter surface of the outer member .

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