JP5571460B2 - 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, as shown in FIG. 19, a strain gauge 91 is attached to an outer ring 90 that is a fixed ring of a wheel bearing, and the load is detected by detecting a strain. A bearing has been proposed (for example, Patent Document 1).

Special table 2003-530565 gazette

  However, in the configuration in which the strain gauge 91 is attached to the outer ring 90 of the wheel bearing as shown in FIG. 19, the sensor is not protected from the external environment. For this reason, there is a possibility that the pebbles and the like jumped while the vehicle is running will hit the sensor and damage the sensor, or the sensor may be corroded by being covered with muddy salt water.

  In order to solve the above problems, the present inventors have proposed the structure shown in FIGS. 20 and 21 (Japanese Patent Application No. 2009-244303). In this proposed example, as shown in FIG. 20, a plurality of sensor units 120 for load detection are provided on the outer peripheral surface of an outer member 101 which is a fixed ring of a wheel bearing, and the plurality of sensor units 120 are connected to the outer member. It is covered with a cylindrical protective cover 129 surrounding 101. The outboard side end of the protective cover 129 is fitted to the outer peripheral surface of the outer member 101, and a lip made of an annular elastic body provided along the opening edge of the inboard side end of the protective cover 129 as shown in FIG. The portion 135 is brought into contact with the side surface of the flange 101a for mounting the vehicle body provided on the outer periphery of the outer member 101 and facing the outboard side. In addition to the sensor unit 120, a signal processing circuit for processing the output signal of the sensor unit 120 and a signal cable for extracting the processed output signal to the outside of the bearing are attached to the flexible substrate 130 to form an annular sensor assembly. The sensor assembly is attached to the outer peripheral surface of the outer member 101 concentrically therewith. As shown in FIG. 21, a hole 136 through which the signal cable protective cover 129 is drawn out is provided at the inboard side end of the protective cover 129, and the signal cable lead-out part 132 B is drawn out from the hole 136. Sealing material 137 is applied to the portion. Accordingly, the sensor unit 120 and other electronic components are covered with the protective cover 129, and these can be protected from the external environment.

  However, in the above proposed example, when the signal cable is attached to the protective cover 129, it is necessary to process the signal cable so that the signal cable does not interfere when the bearing is assembled, and the protective cover 129 and the signal are also removed when the protective cover 129 is removed. Since an operation such as peeling off the sealing material 137 provided between the cables is required, there is a problem that the number of man-hours for assembly and disassembly of the bearing increases.

  An object of the present invention is a sensor that has a compact configuration, has good assemblability such as signal cable drawing processing, has a reliable sensor unit protection and high detection reliability, and can accurately detect a load applied to a bearing portion of a wheel. It is to provide a bearing for a wheel with a wheel.

  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 plurality of rolling elements interposed between the opposing rolling surfaces of the member, and the fixed side member of the outer member and the inner member has a flange for mounting the vehicle body attached to the knuckle on the outer periphery, In a wheel bearing for rotatably supporting a wheel with respect to a vehicle body, a plurality of sensor units for load detection fixed to the outer peripheral surface of the fixed side member are provided, and the plurality of sensor units are connected to the fixed side member. A waterproof protective connector is provided to take out the output signal of the sensor unit or a signal obtained by calculating the output signal to the outside of the bearing together with the protective cover that surrounds the outer periphery of the sensor. Features. In this case, the fixed member is, for example, an outer member of the bearing.

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 stationary side member (for example, the outer member) of the wheel bearing to cause deformation. The distortion of the fixed side member is transmitted to the sensor unit and detected with high sensitivity, and the load can be estimated with high accuracy.
In addition, since the plurality of sensor units are covered with a cylindrical protective cover that surrounds the outer periphery of the fixed side member, the plurality of sensor units can be protected from the external environment, and the sensor unit can be prevented from being damaged by the external environment. Thus, the load acting on the wheel bearing and the tire ground contact surface can be accurately detected over a long period of time. In particular, a waterproof connector for taking out the output signal of the sensor unit or a signal obtained by processing the output signal to the outside of the bearing is provided integrally with the protective cover, so the signal connected to the sensor unit etc. when assembling the bearing The troublesome operation of taking out the cable from the protective cover so as not to interfere with the protective cover is not required, the structure is compact, the assembly is good, and the load applied to the bearing portion of the wheel can be accurately detected.
When the stationary member is the outer member, the protective cover is attached to the outer peripheral surface of the outer member. In this case, the protective cover can be easily attached and the sensor unit can be easily protected by the protective cover.

  In this invention, the outboard side end of the protective cover is fitted to the outer peripheral surface of the fixed side member, and the lip portion made of an annular elastic body provided along the opening edge of the inboard side end of the protective cover You may make it contact | abut to the side surface which faces the outboard side of the flange of a stationary-side member.

  In the present invention, the elastic body constituting the lip portion may be made of a rubber material. When the elastic body constituting the lip portion is a rubber material, the sealing performance of the inboard side end of the protective cover can be ensured. In addition, the lip portion may be integrally formed with the protective cover.

  In the present invention, the lip portion may have a shape whose diameter increases toward the inboard side. In the case of this configuration, the intrusion of muddy water, salt water or the like from the inboard side end into the protective cover can be more reliably prevented.

  In this invention, the protective cover may be formed by pressing a steel plate having corrosion resistance. In this configuration, the protective cover can be prevented from being corroded by the external environment.

  In the present invention, the protective cover may be formed by pressing a steel plate and performing metal plating or coating treatment on the surface thereof. Also in this configuration, the protective cover can be prevented from being corroded by the external environment.

The output signal of the sensor unit on the outer circumference of the front Symbol stationary member may be provided with arithmetic processing circuit performing arithmetic processing.

  In this invention, the arithmetic processing circuit may be resin-molded integrally with the waterproof connector. In the case of this configuration, the connection work between the arithmetic processing circuit and the waterproof connector can be omitted. The sensor unit and the arithmetic processing circuit are connected when the protective cover is attached to the fixed member.

Pre Symbol arithmetic processing circuit, Ru includes a load estimating means for estimating a load applied to the wheel from the output signal of the sensor unit.

Pre Symbol arithmetic processing circuit includes a first load estimating means for estimating a load acting on the wheel support bearing using the average value of the output signal of the sensor unit, the amplitude value of the output signal of the sensor unit or the amplitude thereof, A second load estimating means for estimating a load acting on the wheel bearing using the value and the average value, and an estimation of one of the first and second load estimating means according to the wheel rotational speed Ru and a selection output means for selecting switching the load value.
In the case of this configuration, the detection processing time can be shortened by outputting the estimated load value of the first load estimating means obtained from the average value obtained without performing the time averaging process when the wheel is stationary or at a low speed. Further, when the wheel is in the normal rotation state, the average value and the amplitude value of the output signal can be calculated with high accuracy. Therefore, the estimated load value of the second load estimating means obtained from the amplitude value or the average value and the amplitude value can be obtained. By outputting, the error of the estimated load value is reduced, and the detection delay time is sufficiently shortened.
As a result, the load applied to the wheel can be accurately estimated, and the detected load signal can be output without delay. For this reason, the responsiveness and controllability of the vehicle control using the load signal are improved, and safety and running stability can be further improved.

  In this case, the sensor unit has three or more contact fixing portions and two sensors, and is between the adjacent first and second contact fixing portions and between the adjacent second and third contact fixing portions. The sensors are respectively mounted between them, and the interval between the contact fixing portions adjacent to each other or the circumferential direction of the fixed side member of the adjacent sensors is {1/2 + n (n: integer)} times the arrangement pitch of the rolling elements, The first and second load estimating means may use the sum of output signals of the two sensors as an average value. In the case of this configuration, the output signals of the two sensors have a phase difference of about 180 degrees, and the average value is a value obtained by canceling the fluctuation component due to passing through the rolling elements. Thereby, the load estimation using the average value becomes more accurate.

  In the present invention, the sensor unit may be attached to a flexible substrate. As described above, the sensor unit can be easily attached by attaching the sensor unit to the flexible substrate.

  Furthermore, an arithmetic processing circuit that performs arithmetic processing on the output signal of the sensor unit and a signal cable that connects the arithmetic processing circuit to the waterproof connector may be attached to the flexible substrate. In this way, by attaching the sensor unit, arithmetic processing circuit, and signal cable to the flexible substrate, and forming the wiring circuit pattern on the flexible substrate, the connection between the sensor unit, arithmetic processing circuit, and signal cable can be facilitated. It can be carried out.

  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 unit is arranged at 90 degrees in the circumferential direction 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 fixed side member that is in the vertical position and the horizontal position with respect to the tire ground contact surface. Four of them may be equally arranged with a phase difference.
Thus, by arranging four sensor units, it is possible to estimate the vertical load Fz acting on the wheel bearing, the load Fx serving as the driving force and the braking force, and the axial load Fy.

In the present invention, the front shape of the flange of the stationary member may be a shape that is line symmetric with respect to a line segment orthogonal to the bearing axis or a shape that is point symmetric with respect to the bearing axis.
In the case of this configuration, the shape of the fixed side member is simplified, and variations in temperature distribution and expansion / contraction amount due to the complexity of the shape of the fixed side member can be reduced. Thereby, the influence by the variation in the temperature distribution and the expansion / contraction amount in the fixed side member can be sufficiently reduced, and the strain amount due to the load can be detected by the sensor unit.

In this invention, you may give the surface treatment which has corrosion resistance or corrosion resistance to the surrounding surface in which the flange of the said stationary-side member is provided. The surface treatment in this case is, for example, metal plating, painting, or coating treatment.
In this way, when the peripheral surface on which the flange of the fixed side member is provided is subjected to corrosion resistance or anticorrosive surface treatment, the mounting portion of the sensor unit rises due to rust on the peripheral surface of the fixed side member, or the sensor unit receives it. Rust can be prevented from occurring, malfunction of the sensor unit due to rust can be eliminated, and load detection can be accurately performed over a longer period.

The method of assembling the sensor-equipped wheel bearing according to the present invention is the method of assembling the sensor-equipped wheel bearing according to the present invention, wherein the stationary member is a single member or the rolling element is assembled to the stationary member. The sensor unit is attached to the peripheral surface of the fixed side member, and further, the bearing is assembled after the protective cover is attached to the peripheral surface of the fixed side member.
According to this assembling method, the sensor-equipped wheel bearing in which the sensor unit and the protective cover are attached to the stationary member can be easily assembled.

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 plurality of rolling elements interposed between the opposing rolling surfaces of the member, and the fixed side member of the outer member and the inner member has a flange for mounting the vehicle body attached to the knuckle on the outer periphery, In a wheel bearing that rotatably supports a wheel with respect to a vehicle body, a plurality of sensor units for load detection fixed to the outer diameter surface of the fixed side member are provided, and the plurality of sensor units are connected to the fixed side. covered with a cylindrical protective cover surrounding the outer periphery of the member, the protective cover integrally, the only setting a waterproof connector for taking out an output signal or an output signal of the arithmetic processed signals to the outside of the bearing of the sensor unit, wherein The outer periphery of the fixed side member An arithmetic processing circuit for arithmetically processing the output signal of the sensor unit is provided, and the arithmetic processing circuit includes load estimating means for estimating a load applied to the wheel from the output signal of the sensor unit, and the arithmetic processing circuit includes the sensor unit First load estimating means for estimating the load acting on the wheel bearing using the average value of the output signal of the motor and the amplitude value of the output signal of the sensor, or the amplitude value of the sensor and the average value for the wheel A second load estimating means for estimating a load acting on the bearing, and a selection output for switching and outputting one of the estimated load values of the first and second load estimating means according to the wheel rotational speed order to and means, a compact configuration, assembly of the withdrawal process or the like of the signal cable is good, protection of the sensor unit is reliable reliable detection, the load applied to the bearing portion of the wheel It can be accurate.
The method for assembling the sensor-equipped wheel bearing according to the present invention is an assembly method for assembling the sensor-equipped wheel bearing according to the present invention, wherein the stationary member is in a single state or the rolling element is assembled in the stationary member. Since the sensor unit is attached to the peripheral surface of the fixed side member and the protective cover is further attached to the peripheral surface of the fixed side member, the bearing is assembled. Therefore, the sensor unit and the protective cover are attached to the fixed side member. The sensor wheel bearing can be easily assembled.

It is sectional drawing of the bearing for wheels with a sensor concerning one Embodiment of this invention. It is sectional drawing of the outward member of the wheel bearing with a sensor. It is the front view which looked at the outward member from the outboard side. It is an enlarged plan view of a sensor unit in the wheel bearing with sensor. It is a VV arrow sectional view in FIG. (A) is an expanded top view of an example of a flexible substrate, (B) is VIb-VIb arrow sectional drawing of (A). (A) is an expansion | deployment top view of the other example of a flexible substrate, (B) is the same sectional drawing. (A) is a development top view of the further another example of a flexible substrate, (B) is the same sectional drawing. (A) is a development top view of the further another example of a flexible substrate, (B) is the same sectional drawing. It is explanatory drawing of the influence of a rolling-element position with respect to the output signal of a sensor unit. It is a block diagram which shows an example of the whole structure of the detection system in the bearing for wheels with the said sensor. It is a block diagram of the circuit example of the calculating part which calculates the average value and amplitude value of a sensor output signal. It is a block diagram of the circuit part which estimates and outputs a load from an average value and an amplitude value. It is sectional drawing of the outward member in the bearing for wheels with a sensor concerning other embodiment of this invention. It is the front view which looked at the outward member from the outboard side. It is sectional drawing of the outward member in the bearing for wheels with a sensor concerning further another embodiment of this invention. It is the front view which looked at the outward member from the outboard side. It is sectional drawing of the bearing for wheels with a sensor concerning further another embodiment of this invention. It is a perspective view of a prior art example. It is a front view of a proposal example. It is sectional drawing of a proposal example.

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

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

The outer member 1 is a fixed side member, and has a vehicle body mounting flange 1a attached to a knuckle 16 in a suspension device (not shown) of the vehicle body on the outer periphery, and the whole is an integral part. The flange 1a is provided with screw holes 14 for attaching a knuckle at a plurality of locations in the circumferential direction, and knuckle bolts (not shown) inserted into the bolt insertion holes 17 of the knuckle 16 from the inboard side are screwed into the screw holes 14. Thus, the vehicle body mounting flange 1a is attached to the knuckle 16.
The inner member 2 is a rotating side member, and includes a hub wheel 9 having a hub flange 9a for wheel mounting, and an inner ring 10 fitted to the outer periphery of the end portion on the inboard side of the shaft portion 9b of the hub wheel 9. And become. The hub wheel 9 and the inner ring 10 are formed with the rolling surfaces 4 of the respective rows. An inner ring fitting surface 12 having a small diameter with a step is provided on the outer periphery of the inboard side end of the hub wheel 9, and the inner ring 10 is fitted to the inner ring fitting surface 12. A through hole 11 is provided at the center of the hub wheel 9. The hub flange 9a is provided with press-fitting holes 15 for hub bolts (not shown) at a plurality of locations in the circumferential direction. In the vicinity of the base portion of the hub flange 9a of the hub wheel 9, a cylindrical pilot portion 13 for guiding a wheel and a braking component (not shown) protrudes toward the outboard side.

  FIG. 2 shows a cross-sectional view of the outer member 1 in this wheel bearing, and FIG. 3 shows a front view of the outer member 1 viewed from the outboard side. 2 shows a cross-sectional view taken along arrow II-II in FIG. The vehicle body mounting flange 1a has a shape in which the front surface shape is symmetrical with respect to a line segment perpendicular to the bearing axis O (for example, a vertical line segment LV or a horizontal line segment LH in FIG. 3), or a bearing axis O The shape is point-symmetric with respect to. Specifically, in this example, the front shape is a circle that is line symmetric with respect to the vertical line segment LV.

  Four sensor units 20 are provided on the outer diameter surface of the outer member 1 that is a stationary member. Here, these sensor units 20 are arranged in the circumferential direction 90 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 and rear position with respect to the tire ground contact surface. They are equally distributed with a phase difference of degrees.

  As shown in the enlarged plan view and the enlarged sectional view in FIGS. 4 and 5, these sensor units 20 are attached to the strain generating member 21 and detect the strain 2 of the strain generating member 21. The two strain sensors 22A and 22B. 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 of 2 mm or less, and has a planar shape with a strip shape having a uniform width over the entire length, and has notches 21b on both sides. The corner of the notch 21b has an arcuate cross section. The strain generating member 21 has three contact fixing portions 21 a that are contact-fixed to the outer diameter surface of the outer member 1 via the spacers 23. The three contact fixing portions 21 a are arranged in a line in the longitudinal direction of the strain generating member 21. That is, in FIG. 5, one strain sensor 22A is arranged between the contact fixing portion 21a at the left end and the contact fixing portion 21a at the center, and the other between the contact fixing portion 21a at the center and the contact fixing portion 21a at the right end. One strain sensor 22B is arranged. As shown in FIG. 4, the notches 21 b are formed at two positions corresponding to the placement portions of the strain sensors 22 </ b> A and 22 </ b> B on both sides of the strain generating member 21. Thereby, the strain sensors 22A and 22B detect the strain in the longitudinal direction around the notch 21b of the strain generating member 21. 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 assumed maximum force is, for example, the maximum force within a range in which the normal functioning of the wheel bearing is restored when the force is removed without the wheel bearing being damaged. .

  In the sensor unit 20, the three contact fixing portions 21a of the strain generating member 21 are at the same position in the axial direction of the outer member 1, and the contact fixing portions 21a are positioned away from each other in the circumferential direction. These contact fixing portions 21 a are respectively fixed to the outer diameter surface of the outer member 1 by bolts 24 through spacers 23. At this time, the flexible substrate 30 disposed on the upper surface of the sensor unit 20 is also fixed to the outer diameter surface of the outer member 1 together with the sensor unit 20. The flexible substrate 30 is a strip-shaped single substrate disposed in a ring shape concentrically with the outer member 1 along the outer diameter surface of the outer member 1. That is, the four sensor units 20 are attached to the back surface side of one flexible substrate 30 and are fixed to the outer diameter surface of the outer member 1 together with the flexible substrate 30. Since the flexible substrate 30 is arranged in a ring shape along the outer diameter surface of the outer member 1, the base material is preferably polyimide. When the base material of the flexible substrate 30 is polyimide, the flexible substrate 30 can have sufficient flexibility and heat resistance, and can be easily along the circumferential direction of the outer member 1.

  Each of the bolts 24 is inserted from a bolt insertion hole 30a of the flexible substrate 30 into a bolt insertion hole 25 provided in the contact fixing portion 21a of the strain generating member 21 in the radial direction and a bolt insertion hole 26 of the spacer 23. Then, the outer member 1 is screwed into the screw hole 27 provided in the outer peripheral portion. A washer 28 is interposed between the head of the bolt 24 and the distortion generating member 21. In this way, by fixing the contact fixing portion 21a to the outer diameter surface of the outer member 1 via the spacer 23, each portion having the cutout portion 21b in the strain generating member 21 which is a thin plate shape becomes the outer member 1. It becomes a state away from the outer diameter surface of this, and distortion deformation around the notch 21b becomes easy. As the axial position where the contact fixing portion 21a is disposed, an axial position that is the periphery of the rolling surface 3 of the outboard side row of the outer member 1 is selected here. Here, the periphery of the rolling surface 3 of the outboard side row is a range from the intermediate position of the rolling surface 3 of the inboard side row and the outboard side row to the formation portion of the rolling surface 3 of the outboard side row. It is. In order to stably fix the sensor unit 20 to the outer diameter surface of the outer member 1, a flat portion 1 b is formed at a location where the spacer 23 is contacted and fixed on the outer diameter surface of the outer member 1.

  As the strain sensors 22A and 22B, various sensors can be used. For example, the strain 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. Further, the strain sensors 2222A and 22B can be formed on the strain generating member 21 with a thick film resistor.

  6A and 6B are a plan development view and a sectional view of an arrangement example of the sensor unit 20 on the flexible substrate 30. FIG. In this arrangement example, four sensor units 20 are directly mounted on the flexible substrate 30. The sensor unit 20 is attached to the back surface of the flexible substrate 30 (the surface facing the outer diameter surface of the outer member 1), and the wiring circuit 34 is printed as a circuit pattern on the back surface, front surface, or both front and back surfaces of the flexible substrate 30. . The sensor unit 20 is connected to the wiring circuit 34 by soldering or the like. 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 34 of the flexible substrate 30. It attaches to the flexible substrate 30 so that it becomes. In this example, strip-shaped openings 30 b extending in the longitudinal direction of the flexible substrate 30 are formed in portions corresponding to both side portions of the sensor unit 20 in the sensor unit arrangement portion of the flexible substrate 30. 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 30 has an arithmetic processing circuit 31 for processing output signals of the strain sensors 22A and 22B together with the four sensor units 20, and an output terminal of the arithmetic processing circuit 31 is connected to a waterproof connector 81A (FIG. Electronic components such as the signal cable 32 connected to 1) are connected in a ring shape, and the sensor assembly 33 is configured. The arithmetic processing circuit 31 is composed of, for example, an integrated circuit chip. The ring-shaped sensor assembly 33 is attached to the outer diameter surface of the outer member 1 concentrically with the outer member 1.

  The waterproof connector 81A is a connector that serves as a socket in a plug-and-connect type connector set 81 including a socket and a plug, and protrudes from the bottom surface of the connector body 81Aa having a rectangular tube shape with one end opened. And a plurality of pin-shaped connection terminals 81Ab. The plurality of connection terminals 81Ab may be attached to the terminal board and attached to the connector main body 81Aa via the terminal board, or may be attached directly to the connector main body 81Aa. The signal cable 32 is connected to the connection terminal 81Ab. A connector 81B serving as a plug is inserted and connected to the connector 81A serving as a socket. A connector 81B serving as a plug is provided at the tip of a cable 89 for extracting signals from the wheel bearing. The connector 81B serving as a plug is provided in a connector body 81Ba to be inserted and fitted into the connector body 81Aa of the connector 81A serving as a socket, and provided in a recess provided in the distal end surface of the connector body 81Ba to serve as the socket. It consists of a plurality of connection terminals 81Bb that are in contact with and connected to the connection terminals 81Ab of the connector 81A. In the connector 81A serving as the socket, the connector main body 81Aa has a shape in which the peripheral surface of the connector main body 81Ba of the connector 81B serving as a plug is inserted without a gap. It is a waterproof type that does not enter.

FIGS. 7A and 7B are a plan development view and a sectional view of another arrangement example of the sensor unit 20 on the flexible substrate 30. FIG. Also in this arrangement example, all of the sensor units 20 are mounted on the flexible substrate 30. In this arrangement example, a rectangular opening 30 c is formed in the sensor unit arrangement portion of the flexible substrate 30 so that substantially the entire sensor unit 20 is exposed.
In this way, by forming the rectangular opening 30 c in which the entire sensor unit 20 is exposed in the arrangement portion of the sensor unit 30 in the flexible substrate 30, the deformation of the strain generating member 21 in the sensor unit 20 is caused by the flexible substrate 30. 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.

FIGS. 8A and 8B are a plan development view and a cross-sectional view of still another arrangement example of the sensor unit 20 on the flexible substrate 30. FIG. In this arrangement example, each sensor unit 20 is separated from the flexible substrate 30 except for a connection portion between the flexible substrate 30 and the wiring circuit 34.
In addition, the flexible substrate 30 has the mounting portion of the arithmetic processing circuit 31 as a wide portion, the other portion as a narrow portion, and each sensor unit 20 is disposed on the side of the narrow portion of the flexible substrate 30, so that The arrangement configuration is not widened. Thereby, the sensor assembly 33 can be comprised compactly. Other configurations are the same as those in the arrangement example shown in FIG.

  9A and 9B are a plan development view and a cross-sectional view of still another arrangement example of the sensor unit 20 on the flexible substrate 30. FIG. Also in this arrangement example, each sensor unit 20 is separated from the flexible substrate 30 except for the connection portion with the wiring circuit 34 of the flexible substrate 30 as in the case of FIG. However, in this arrangement example, the flexible substrate 30 is formed in a strip shape having the same width, and each sensor unit 20 is arranged along one side of the flexible substrate 30 along the flexible substrate 30. Other configurations are the same as those in the arrangement example shown in FIG.

  The strain sensors 22A and 22B of each sensor unit 20 are connected to the arithmetic processing circuit 31 through the wiring circuit 34 of the flexible substrate 30. The arithmetic processing circuit 31 performs arithmetic processing on the output signals of the strain sensors 22A and 22B to obtain force (vertical load Fz, driving force and braking force) acting between the wheel bearing and the wheel and the road surface (tire contact surface). This is a circuit for estimating the load Fx and the axial load Fy). An example of the configuration of the arithmetic processing circuit 31 is shown in a block diagram in FIG.

  In the configuration example of the arithmetic processing circuit 31 shown in FIG. 11, the strain sensor 22 of each sensor unit 20 is connected to the load estimating means 50 via the AD converter 49. That is, the output signal of the strain sensor 22 is directly AD converted by the AD converter 49, and the output signal of the strain sensor 22 subjected to the AD conversion is input to the load estimating means 50. In this case, an AD converter 49 having a resolution of at least 20 bits is used. The AD converter 49 is a small multi-channel input element, and constitutes a conversion unit 59 that combines sensor output signals from a plurality of sensor units 20 into digital data. The AD converter 49 is preferably a digital sigma converter because it has high accuracy and relatively high speed characteristics.

  The load estimator 50 generates force (vertical load Fz, driving force and braking force) acting on the wheel bearing and between the wheel and the road surface (tire contact surface) from the AD-converted output signal of the strain sensor 22 of the sensor unit 20. The load Fx and the axial load Fy) are estimated by, for example, a microcomputer. The load estimating means 50 composed of this microcomputer may be one in which various electronic components are mounted on one substrate or one chip. The load estimation unit 50 includes an offset adjustment circuit 51, a temperature correction circuit 52, a filter processing circuit 53 such as a low-pass filter, a load estimation calculation circuit 54, a control circuit 55, and the like. The offset adjustment circuit 51 adjusts the initial offset of the strain sensor 22 and the offset due to fixing to the wheel bearing to a normal value. Adjustment by the control circuit 55 or offset adjustment by an external command is performed. It is configured as possible. That is, the offset adjustment circuit 51 performs offset adjustment as a normalization process. Since the cause of the offset is a variation in the strain sensor 22 or a strain when the sensor is fixed, it is desirable to attach the sensor unit 20 to the wheel bearing and adjust the offset when the assembly is completed.

  As described above, after the assembly of the sensor-equipped wheel bearing is completed, when the offset is adjusted by the offset adjustment circuit 51 so that the output signal of the strain sensor 22 becomes the specified value, the sensor-equipped wheel bearing is completed. Therefore, the sensor output signal quality can be ensured.

  In addition, the output signal of the strain sensor 22 includes a drift amount due to temperature characteristics of the strain sensor itself, temperature distortion of the outer member 1 that is a fixed member, and the like. The temperature correction circuit 52 is a circuit that corrects drift caused by the temperature of the output signal of the strain sensor 22 that has been offset adjusted. In order to correct the drift due to temperature, a temperature sensor 29 is provided in the strain generating member 21 of at least one sensor unit 20 as shown in FIG. 4, and an output signal of the temperature sensor 29 is digitized by an AD converter 49. And then input to the temperature correction circuit 52.

  In the load estimation calculation circuit 54, based on the digitized output signal of the strain sensor 22 subjected to the offset adjustment process, the temperature correction process, the filter process, and the like by the offset adjustment circuit 51, the temperature correction circuit 52, and the filter processing circuit 53. A load estimation calculation is performed. The load estimation calculation circuit 54 is a relationship setting in which the relationship between the vertical load Fz, the load Fx as a driving force or braking force, the axial load Fy, and the output signal of the strain sensor 22 is set by an arithmetic expression or a table. Means (not shown), and using the relation setting means from the output signal of the strain sensor 22, the acting force (vertical load Fz, load Fx serving as driving force or braking force, axial load Fy) is estimated. . The setting contents of the relationship setting means are obtained by a test or simulation in advance. The load data obtained by the load estimation calculation circuit 54 of the load estimating means 50 is output to an upper electric control unit (ECU) installed on the vehicle body side through an in-vehicle communication bus (for example, CAN bus). This communication path may be wireless, and may be configured such that a transmitter / receiver is installed on each of the bearing side and the vehicle body side to output load data and the like. In this case, it is possible to reduce the number of necessary cables by attaching the necessary cables such as power supply and operating the sensor and transmitting the obtained data wirelessly. Becomes easier. The electric control unit is, for example, a unit that controls the entire vehicle, and includes a microcomputer or the like. It is good also as what outputs with an analog voltage as needed.

  The load estimation calculation circuit 54 of the load estimation means 50 includes an average calculation unit 68 and an amplitude calculation unit 69 shown in FIG. The average calculation unit 68 includes an adder, calculates the sum of the output signals of the two strain sensors 22A and 22B of the sensor unit 20, and extracts the sum as an average value A. The amplitude calculation unit 69 includes a subtracter, calculates the difference between the output signals of the two strain sensors 22A and 22B, and extracts the difference value as the amplitude value B.

  In the load estimation calculation circuit 54, a force F (for example, a force acting on the wheel bearing or between the wheel and the road surface (tire contact surface) is calculated from the average value A and the amplitude value B calculated by the average calculation unit 68 and the amplitude calculation unit 69. Calculate and estimate the vertical load Fz). For the calculation and estimation, the load estimation calculation circuit 54 has two load estimation means 71 and 72 shown in FIG. The first load estimating means 71 uses the average value A to calculate / estimate the load F acting on the wheel bearing. The second load estimating means 72 calculates and estimates the load F acting on the wheel bearing using the average value A and the amplitude value B.

The relationship between the load F acting on the wheel bearing and the output signal S of the strain sensors 22A and 22B is as follows:
F = M1 × S (1)
The load F can be estimated from this relational expression (1). Here, M1 is a predetermined correction coefficient.
In the first load estimation means 71, the average value A is used as a variable obtained by removing the offset from the output signals of the strain sensors 22A and 22B, and this variable is multiplied by a predetermined correction coefficient M1, that is, F = M1 × A (2)
The load F is calculated and estimated from the above. In this way, the load estimation accuracy can be improved by using the variable excluding the offset.

In the second load estimating means 72, the average value A and the amplitude value B are used as variables, and these variables are multiplied by predetermined correction coefficients M2 and M3, that is, F = M2 × A + M3 × B. (3)
The load F is calculated and estimated from the above. Thus, load estimation accuracy can be further improved by using two types of variables.
The value of each correction coefficient in each of the above arithmetic expressions is set by obtaining in advance by a test or simulation. The calculations by the first load estimating means 71 and the second load estimating means 72 are performed in parallel. In equation (3), the average value B, which is a variable, may be omitted. That is, the second load estimation means 72 can also calculate and estimate the load F using only the amplitude value B as a variable.

  Since the sensor unit 20 is provided at an axial position around the rolling surface 3 of the outboard side row of the outer member 1 as shown in FIG. 1, the output signals a and b of the strain sensors 22A and 22B are shown in FIG. 10 is affected by the rolling element 5 passing through the vicinity of the installation part of the sensor unit 20. That is, the influence of this rolling element 5 acts as an offset. Even when the bearing is stopped, the output signals a and b of the strain sensors 22A and 22B are affected by the position of the rolling element 5. That is, when the rolling element 5 passes the position closest to the strain sensors 22A and 22B in the sensor unit 20 (or when the rolling element 5 is at that position), the amplitude of the output signals a and b of the strain sensors 22A and 22B. Becomes the maximum value, and decreases as the rolling element 5 moves away from the position as shown in FIGS. 10A and 10B (or when the rolling element 5 is located away from the position). When the bearing rotates, the rolling elements 5 sequentially pass through the vicinity of the installation portion of the sensor unit 20 at a predetermined arrangement pitch P, so that the analog output signals a and b of the strain sensors 22A and 22B have an amplitude of the rolling elements 5. A waveform similar to a sine wave that periodically changes as shown in FIG. Therefore, in the load estimation calculation circuit 54 in the calculation processing circuit 31, as the data for obtaining the load, the sum of the amplitudes of the output signals a and b of the two strain sensors 22A and 22B is set to the above-described average value A, and the amplitude difference is obtained. (Absolute value) | a−b | is the amplitude value B described above. Thus, the average value A is a value obtained by canceling the fluctuation component due to the passage of the rolling elements 5. The amplitude value B is a value that offsets the influence of temperature appearing in the output signals a and b of the two strain sensors 22A and 22B and the influence of slippage between the knuckle and flange surfaces. Therefore, by using the average value A and the amplitude value B, the load acting on the wheel bearing and the tire ground contact surface can be accurately detected.

  Here, the sensor unit 20 includes two contact fixing portions 21a positioned at both ends of the array among the three contact fixing portions 21a arranged in the circumferential direction of the outer diameter surface of the outer member 1 which is a fixed side member. The interval is set to be the same as the arrangement pitch P of the rolling elements 5. In this case, the circumferential interval between the two strain sensors 22A and 22B respectively disposed at the intermediate positions of the adjacent contact fixing portions 21a is approximately ½ of the arrangement pitch P of the rolling elements 5. . As a result, the output signals a and b of the two strain sensors 22A and 22B have a phase difference of about 180 degrees, and the average value A obtained as the sum is obtained by canceling the fluctuation component due to the passage of the rolling element 5. It becomes. Further, the amplitude value B obtained as the difference is a value obtained by offsetting the influence of temperature and the influence of slippage between the knuckle and the flange surface.

In FIG. 10, the interval between the contact fixing portions 21 a is set to be the same as the arrangement pitch P of the rolling elements 5, and one strain sensor 22 </ b> A, 22 </ b> B is disposed at an intermediate position between the adjacent contact fixing portions 21 a. Thus, the circumferential interval between the two strain sensors 22A and 22B is set to be approximately ½ of the arrangement pitch P of the rolling elements 5. Alternatively, the circumferential interval between the two strain sensors 22A and 22B may be directly set to ½ of the arrangement pitch P of the rolling elements 5.
In this case, the circumferential interval between the two strain sensors 22A and 22B may be {1/2 + n (n: integer)} times the arrangement pitch P of the rolling elements 5, or a value approximated to these values. good. Also in this case, the average value A obtained as the sum of the output signals a and b of both strain sensors 22A and 22B is a value obtained by canceling the fluctuation component due to the passage of the rolling element 5, and the amplitude value B obtained as the difference is the temperature. It is a value that offsets the influence and the effect of slippage between the knuckle and flange surfaces.

As shown in FIG. 13, both load estimation means 71 and 72 of the load estimation calculation circuit 54 are connected to the selection output means 73 in the next stage. The selection output means 73 switches and selects one of the estimated load values of the first and second load estimation means 72 according to the wheel rotation speed and outputs it. Specifically, the selection output means 73 selects and outputs the estimated load value of the first load estimation means 71 when the wheel rotation speed is lower than a predetermined lower limit speed.
When the wheel rotates at a low speed, the processing time for detecting the amplitude of the sensor output signal becomes longer, and further, the amplitude cannot be detected when the wheel is stationary. Thus, in this way, when the wheel rotation speed is lower than the predetermined lower limit value, the detected load is obtained by selecting and outputting the estimated load value from the first load estimating means 71 using only the average value A. The signal can be output without delay.

  In this embodiment, a rolling element detection sensor 60 for detecting the position of the rolling element 5 is provided on the inner periphery of the outer member 1 as shown in FIG. The rotational speed of the wheel is obtained from the output signal of the rolling element detection sensor 60. The selection output means 73 may receive information on wheel rotation speed from the outside. In this case, as information on the wheel rotation speed from the outside, a rotation sensor signal such as an ABS sensor from the vehicle body side may be used to estimate the wheel rotation speed. Moreover, it is good also as a structure which the selection output means 73 receives a switching selection instruction | command from the high-order control apparatus connected to the in-vehicle communication bus | bath by the side of a vehicle body as an alternative to the wheel rotational speed information. Further, as the wheel rotation speed information, the wheel rotation speed may be estimated by detecting the passing frequency of the rolling element 5 from the output signals a and b of the strain sensors 22A and 22B.

  In this embodiment, 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 the fixed side member, which are in the vertical position and the horizontal position with respect to the tire contact surface, Since the four sensor units 20 are equally arranged with a phase difference of 90 degrees in the direction, it is possible to estimate the vertical load Fz acting on the wheel bearing, the load Fx serving as a driving force and a braking force, and the axial load Fy. it can.

  The sensor assembly 33 including the sensor unit 20 attached to the outer diameter surface of the outer member 1 is covered with a protective cover 80 as shown in FIG. The protective cover 80 is a cylindrical member that surrounds the outer periphery of the outer member 1, and specifically, a stepped cylinder in which the inboard side half is the large diameter portion 80a and the outboard side half is the small diameter portion 80b. It is made into a shape. The inboard side end of the protective cover 80 is fitted to the outer diameter surface of the flange 1a for mounting the vehicle body, and the outboard side end of the protective cover 80 is fitted to the outer diameter surface of the outer board 1 of the outer member 1. Can be combined. As the material of the protective cover 80, a steel plate having a corrosion resistance such as stainless steel, which is formed by pressing, or a steel plate which is formed by pressing, is subjected to metal plating or coating. Thereby, it can prevent that the protective cover 80 corrodes by an external environment. In addition, the material of the protective cover 80 may be plastic or rubber.

In addition, the protective cover 80 is integrally provided with a waterproof connector 81A for taking out the output signal of the arithmetic processing circuit 31 to the outside of the bearing. The arithmetic processing circuit 31 and the waterproof connector 81A are connected via the signal cable 32. Connected. The waterproof connector 81 </ b> A is integrated with the protective cover 80 by bonding or welding the connector sail 81 a to the protective cover 80. The operation of connecting the signal cable 32 to the waterproof connector 81 </ b> A is performed when the protective cover 80 is attached to the outer member 1.
In this embodiment, the arithmetic processing circuit 31 for arithmetic processing of the output signal of the sensor unit 20 is also provided on the outer periphery of the outer member 1, but the arithmetic processing circuit 31 is omitted and the output signal of the sensor unit 20 is directly used as a bearing. For example, when load estimation is performed by performing output signal arithmetic processing on the vehicle body side, the output terminal of the sensor unit 20 is connected to the waterproof connector 81A via the signal cable 32.

  In this embodiment, the arithmetic processing circuit 31 may be resin-molded integrally with the waterproof connector 81A, or the waterproof connector 81A and arithmetic processing circuit 31 may be integrally injection-molded. When the arithmetic processing circuit 31 is resin-molded integrally with the waterproof connector 81A, the operation of connecting the arithmetic processing circuit 31 and the waterproof connector 80 when the protective cover 80 is attached can be omitted. Further, when the waterproof connector 81A and the arithmetic processing circuit 31 are integrally formed by injection molding, not only these connection operations can be omitted, but also the manufacturing process can be simplified. In these cases, the sensor unit 20 and the arithmetic processing circuit 31 are connected when the protective cover 80 is attached to the outer member 1 that is a fixed member.

  The assembly of the sensor-equipped wheel bearing of this embodiment is performed according to the following procedure. First, the sensor unit 20, the flexible substrate 30, and the arithmetic processing circuit 32 are attached to the outer member 1 in a state where the outer member 1 is a single body or the rolling member 5 is assembled to the outer member 1. Next, the protective cover 80 is inserted from the outboard side of the outer member 1, the inboard side end is fitted to the outer diameter surface of the flange 1 a of the outer member 1, and the outboard side end is fitted to the outer member. The sensor assembly 33 including the sensor unit 20, the flexible substrate 30, the arithmetic processing circuit 32, and the like is covered with the protective cover 80 by being fitted to the outer diameter surface of the cylindrical part 1 on the outboard side. After this, the entire bearing is assembled. By assembling in this procedure, the sensor-equipped wheel bearing in which the sensor unit 20, the flexible substrate 30, and the arithmetic processing circuit 32 attached to the outer member 1 are covered with the protective cover 80 can be easily assembled.

  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, since the two or more contact fixing portions 21 a of the strain generating member 21 in the sensor unit 20 are contact fixed to the outer member 1, the strain of the outer member 1 is transmitted to the strain generating member 21 in an enlarged manner. The distortion is easily detected by the distortion sensor 22.

  In addition, since the sensor assembly 33 including the plurality of sensor units 20 is covered with the cylindrical protective cover 80 that surrounds the outer periphery of the outer member 1 that is the fixed side member, the plurality of sensor units that constitute the sensor assembly 33. 20 and other electronic components can be protected from the external environment, the sensor unit 20 and other electronic components can be prevented from being damaged by the external environment, and the load acting on the wheel bearing and the tire ground contact surface can be accurately detected over a long period of time. It can be detected. In particular, since the waterproof connector 81A for taking out the output signal of the sensor unit 20 or a signal obtained by performing arithmetic processing on the output signal is provided integrally with the protective cover 80, the arithmetic processing circuit 31 is provided when the bearing is assembled. Alternatively, the complicated operation of removing the signal cable connected to the sensor unit 20 from the protective cover 80 so as not to interfere with the protective cover 80 is not required, the structure is compact, the assembly is good, and the load applied to the bearing portion of the wheel is accurate. Can be detected. In the case of this embodiment in which the outer member 1 is a fixed side member, it is easy to attach the protective cover 80 to the outer member 1, and the protective cover 80 can easily protect the sensor unit 20 and other electronic components.

  Further, in this embodiment, the front shape of the vehicle body mounting flange 1a in the outer member 1 which is a stationary member is symmetrical with respect to line segments LV and LH perpendicular to the bearing axis O as shown in FIG. Therefore, the shape of the outer member 1 is simplified, and the temperature distribution and the amount of expansion / contraction caused by the complicated shape of the outer member 1 are obtained. The variation of can be reduced. Thereby, the influence by the variation in the temperature distribution and expansion / contraction amount in the outer member 1 can be made sufficiently small, and the strain amount due to the load can be detected by the sensor unit.

  14 and 15 show another embodiment of the present invention. 1 to 13, the sensor-equipped wheel bearing has the outboard side end of the protective cover 80 attached to the outer diameter surface of the outer member 1 through an O-ring 82. Other configurations are the same as those of the embodiment shown in FIGS.

  As described above, when the outboard side end of the protective cover 80 is attached to the outer diameter surface of the outer member 1 via the O-ring 82, the sealing performance of the outboard side end of the protective cover 80 may be ensured. Thus, the protection effect of the sensor unit 20 and other electronic components by the protective cover 80 can be further improved.

  16 and 17 show still another embodiment of the present invention. 1 to 13, the sensor-equipped wheel bearing is provided with a lip portion 83 formed of an annular elastic body along the opening edge at the inboard side end of the protective cover 80. The portion 83 is brought into contact with the side surface of the outer member 1 facing the outboard side of the vehicle body mounting flange 1a. In this case, the sealing performance of the inboard side end of the protective cover 80 can be ensured, and the protective effect of the sensor unit 20 and other electronic components by the protective cover 80 can be further improved.

  As the elastic body constituting the lip portion 83, a rubber material is desirable. In addition, the lip portion 83 may be integrally formed with the protective cover 80. Here, the lip portion 83 has a shape that expands toward the inboard side. Thereby, infiltration of muddy water, salt water, etc. into the protective cover 80 from the inboard side end can be prevented more reliably. Other configurations are the same as those of the embodiment shown in FIGS.

  FIG. 18 shows still another embodiment of the present invention. In this sensor wheel bearing, in each embodiment shown in FIGS. 1 to 17, a surface treatment layer having corrosion resistance or corrosion resistance on the outer diameter surface provided with the flange 1 a in the outer member 1 which is a fixed member. 84 is formed. The sensor unit 20, the flexible substrate 30, the arithmetic processing circuit 31, and the protective cover 80 are attached to the outer diameter surface of the outer member 1 on which the surface treatment layer 84 is formed as shown in FIGS. Other configurations are the same as those in the embodiments of FIGS.

  Examples of the surface treatment layer 84 having corrosion resistance or corrosion resistance include a surface layer subjected to metal plating treatment, a surface layer subjected to coating treatment, and a surface layer subjected to coating treatment. As the metal plating treatment, treatments such as galvanization, unichrome plating, chromate plating, nickel plating, chrome plating, electroless nickel plating, Kanigen plating, black iron trioxide film (black dyeing), and radient can be applied. As the coating treatment and coating treatment, cationic electrodeposition coating, anion electrodeposition coating, fluorine electrodeposition coating, ceramic coating such as silicon nitride, and the like are applicable.

  Thus, in this embodiment, since the surface treatment layer 84 having corrosion resistance or corrosion resistance is formed on the outer diameter surface of the outer member 1, the sensor unit 20 is caused by rust on the outer diameter surface of the outer member 1. It is possible to prevent the mounting portion of the flexible substrate 30, the arithmetic processing circuit 31, the protective cover 80, etc. from rising, or the sensor unit 20, the flexible substrate 30, the arithmetic processing circuit 31 from generating rust, and a strain sensor caused by rust. Malfunctions such as 22A and 22B can be eliminated, and load detection can be performed accurately over a long period of time.

  In each of the above-described embodiments, the case where the outer member 1 is a fixed side member has been described, but the present invention can also be applied to a wheel bearing in which the inner member is a fixed side member. The sensor unit 20 is provided on the peripheral surface that is the inner periphery of the inner member.

  In these 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 generation or second generation type wheel in which the bearing portion and the hub are independent parts. The present invention can also be applied to a bearing or a fourth-generation type wheel bearing in which a part of the inner member is composed of an outer ring of a constant velocity joint. The sensor-equipped wheel bearing can also be applied to a wheel bearing for a driven wheel, and can also be applied to a tapered roller type wheel bearing of each generation type.

DESCRIPTION OF SYMBOLS 1 ... Outer member 1a ... Car body mounting flange 2 ... Inner member 3, 4 ... Rolling surface 5 ... Rolling body 20 ... Sensor unit 21 ... Strain generating member 21a ... Contact fixing | fixed part 22, 22A, 22B ... Strain sensor 30 ... flexible substrate 31 ... arithmetic processing circuit 32 ... signal cable 71 ... first load estimation means 72 ... second load estimation means 73 ... selection output means 80 ... protective cover 81A ... waterproof connector 83 ... lip portion 84 ... surface treatment layer

Claims (19)

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 The fixed side member of the outer member and the inner member has a flange for mounting the vehicle body attached to the knuckle on the outer periphery, and supports the wheel rotatably with respect to the vehicle body. Wheel bearing
A plurality of load detection sensor units fixed to the outer peripheral surface of the fixed side member are provided, and the plurality of sensor units are covered with a cylindrical protective cover that surrounds the outer periphery of the fixed side member. together, for taking out the processing signal of the output signal or the output signal of the sensor unit to the outside of the bearing, only setting the waterproof connector, to processing the output signal of the sensor unit on the outer circumference of the fixed-side member An arithmetic processing circuit is provided, and the arithmetic processing circuit includes load estimating means for estimating a load applied to the wheel from the output signal of the sensor unit, and the arithmetic processing circuit uses an average value of the output signals of the sensor unit. First load estimating means for estimating the load acting on the wheel bearing and the amplitude value of the output signal of the sensor, or the amplitude value and the average value are used. A second load estimating means for estimating a load acting on the wheel bearing and a switch for selecting and outputting one of the estimated load values of the first and second load estimating means according to the wheel rotational speed. selective output means and the sensor equipped wheel support bearing assembly, characterized that you provided with that.   The sensor-equipped wheel bearing according to claim 1, wherein the fixed-side member is an outer member.   3. The annular elastic body according to claim 1, wherein an outboard side end of the protective cover is fitted to an outer peripheral surface of the fixed side member, and is provided along an opening edge of the inboard side end of the protective cover. The wheel bearing with a sensor which made the lip part which contact | abut contact | abut to the side surface which faces the outboard side of the flange of the said fixed side member.   4. The wheel bearing with sensor according to claim 3, wherein the lip portion is integrally formed with the protective cover.   5. The sensor-equipped wheel bearing according to claim 3, wherein the elastic body constituting the lip portion is made of a rubber material.   6. The sensor-equipped wheel bearing according to claim 3, wherein the lip portion has a shape that increases in diameter toward the inboard side.   The sensor-equipped wheel bearing according to any one of claims 1 to 6, wherein the protective cover is formed by pressing a corrosion-resistant steel plate.   The sensor-equipped wheel bearing according to any one of claims 1 to 6, wherein the protective cover is formed by pressing a steel plate, and the surface thereof is subjected to metal plating or coating treatment. 9. The sensor-equipped wheel bearing according to claim 1 , wherein the arithmetic processing circuit is resin-molded integrally with the waterproof connector. 10. The sensor unit according to claim 1 , wherein the sensor unit includes three or more contact fixing portions and two sensors, and is adjacent between and adjacent to the adjacent first and second contact fixing portions. Each sensor is attached between the second and third contact fixing portions, and the distance between the adjacent contact fixing portions or the adjacent sensors in the circumferential direction of the fixed side member is {1 / of the arrangement pitch of the rolling elements. 2 + n (n: integer)} times, and the first and second load estimation means use the sum of output signals of the two sensors as an average value. In any one of claims 1 to 10, sensor equipped wheel support bearing assembly mounted to the sensor unit to the flexible substrate. 12. The sensor-equipped wheel bearing according to claim 11 , wherein an arithmetic processing circuit that performs arithmetic processing on an output signal of the sensor unit and a signal cable that connects the arithmetic processing circuit to the waterproof connector are attached to the flexible substrate. The wheel bearing with sensor according to claim 11 or 12 , wherein a base material of the flexible substrate is polyimide. The upper surface portion, the lower surface portion, the right surface portion of the outer diameter surface of the fixed side member which is the vertical position and the left and right position with respect to the tire ground contact surface according to any one of claims 1 to 13 . And four wheel bearings with a sensor arranged equally on the left surface with a phase difference of 90 degrees in the circumferential direction. 15. The sensor-equipped wheel bearing according to any one of claims 1 to 14 , wherein a front shape of the flange of the fixed-side member is line-symmetric with respect to a line segment orthogonal to the bearing axis. In any one of claims 1 to 14, wherein the front shape of the flange of the stationary member, the sensor equipped wheel support bearing assembly having a shape which is point symmetry with respect to the bearing axis. The sensor-equipped wheel bearing according to any one of claims 1 to 16 , wherein a surface treatment having corrosion resistance or corrosion resistance is performed on a peripheral surface on which the flange of the fixed side member is provided. 18. The wheel bearing with sensor according to claim 17 , wherein the surface treatment is metal plating, painting, or coating treatment. The method of assembling a sensor-equipped wheel bearing according to any one of claims 1 to 18 , wherein the stationary member is a single member or the rolling member is assembled to the stationary member. A method of assembling a sensor-equipped wheel bearing, comprising: mounting the sensor unit on a peripheral surface of the fixed side member; and further mounting the protective cover on the peripheral surface of the fixed side member;

Images