JP2008213561A - Wheel bearing with sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wheel bearing with a sensor capable of mounting a load sensor without deteriorating bearing rigidity, and accurately detecting an action force between a wheel tire and a road surface. <P>SOLUTION: The bearing is equipped with an outward member 1, an inward member 2, and a double-row rolling body 5, and rotatably supports a wheel with respect to a vehicle body. A fixed side member, for example, the outward member 1 has a flange 1a to be mounted on a knuckle at its outer periphery. Bolt holes 14 are provided at a plurality of circumferential places of the flange 1a. One or more strain sensors 16 are arranged at positions of the same phase as that of the bolt holes 14 of the flange 1a of the outward member 1. A sensor element 18 is mounted on a strain generating member 17 which has two or more contact fixing parts 17a in contact with the outward member 1, and one or more notches 17b so as to measure the strain of the notches 17b. An estimation means 19 is provided for estimating the action force between the wheel tire and the road surface with an output signal of the sensor element 18. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

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

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

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

As a response to such a request, there has been proposed one in which a strain gauge is attached to a fixed ring or a rotating wheel of a wheel bearing, and a load applied to the wheel is estimated from a strain detected by the strain gauge (for example, Patent Documents 1 and 2).
In the wheel bearing disclosed in Patent Document 1, a strain gauge is attached to the outer periphery of the outer ring, which is a fixed ring, and the strain of the outer ring when the rolling element passes is detected by the strain gauge. Further, in the wheel bearing disclosed in Patent Document 2, a plurality of through holes adjacent in the circumferential direction are provided in a wheel mounting flange of a hub wheel that is a rotating wheel, and a strain gauge is provided in a column portion between the adjacent through holes. Is attached, and the strain of the column part is detected with a strain gauge.

There has also been proposed a structure in which a strain-enlarging member having an L-shaped cross section is provided over the body mounting flange of the fixed wheel and the outer diameter surface, and the strain of this strain-enlarging member is detected by a load sensor (
For example, Patent Document 3).
Special table 2003-530565 gazette JP 2004-053331 A JP 2006-0777807 A

However, in the wheel bearing disclosed in Patent Document 1, in order to detect distortion when the rolling element passes,
If the thickness between the rolling surface and the outer periphery of the outer ring is not reduced, distortion cannot be detected, and the bearing rigidity may be lowered. In addition, it is difficult to estimate the load at rest or at a low speed because the strain at the time of passing through the rolling element is detected.

In the wheel bearing disclosed in Patent Document 2, there is a problem that the bearing rigidity is also lowered because a through hole is provided in the wheel mounting flange of the hub wheel and a strain gauge is attached.

In the case of the wheel bearing disclosed in Patent Document 3, it is possible to detect the load with respect to the lateral load (Fy load) on the tire because the relative displacement between the body mounting flange of the fixed wheel and the outer diameter surface is large. However, with respect to a vertical load (Fz load), it is difficult to detect the load because the relative displacement between the body mounting flange of the fixed wheel and the outer diameter surface is small.

The object of the present invention is to attach the load sensor without reducing the bearing rigidity,
The object is to provide a sensor-equipped wheel bearing capable of accurately detecting the acting force between a wheel tire and a road surface regardless of whether the vehicle is stationary or at a low speed.

The sensor-equipped wheel bearing according to the present invention includes an outer member in which a double-row rolling surface is formed on the inner periphery, an inner member in which a rolling surface facing the rolling surface is formed on the outer periphery, and both members. A plurality of rolling elements interposed between the opposing rolling surfaces, on the outer periphery of the fixed member of the outer member and the inner member,
In a wheel bearing having a flange for mounting a vehicle body attached to a knuckle and having bolt holes provided at a plurality of circumferential positions of the flange so as to rotatably support the wheel with respect to the vehicle body, the flange is in contact with the fixed side member. A strain sensor in which a sensor element for measuring the strain of the notch portion is attached to a strain generating member having two or more contact fixing portions and one or more notch portions on an inner diameter surface or an outer diameter surface of the fixed side member. One or more are installed, the notch is arranged at the same phase as the bolt hole of the flange of the fixed side member, and the action between the tire of the wheel and the road surface by the output signal of the sensor element of the strain sensor An estimation means for estimating the force is provided.

When a load acts between the tire of the wheel and the road surface, the load is also applied to the rotating side member of the wheel bearing, and the fixed side member is deformed via the rolling elements. At this time, the position in the same phase as the bolt hole provided in the flange of the fixed side member is fixed to the knuckle in the suspension device of the vehicle body by the bolt, so it hardly deforms and the circumferential direction from the position in the same phase as the bolt hole. The positions on both sides separated from each other are deformed. The deformation is transmitted to the strain generating member installed on the inner diameter surface or the outer diameter surface of the fixed side member, and the strain generating member is deformed. The strain of the strain generating member is measured by a sensor element.
At this time, the strain generating member is deformed in accordance with the radial deformation of the fixed portion of the strain generating member in the fixed side member, but the strain generating member is attached to the most deformed portion in the radial direction. The distortion increases, and a slight distortion of the fixed side member can be detected by the distortion sensor.
Furthermore, since the notch is provided in the strain generating member and the rigidity of the notch is reduced, a strain larger than the strain of the fixed side member appears in the strain generating member, and the fixed side is further increased. A slight distortion of the member can be accurately detected by the sensor element. The force between the wheel tire and the road surface is estimated by the estimation means from the output signal of this sensor element, so the force between the wheel tire and the road surface can be accurately detected regardless of whether it is stationary or at low speed. The detected load can be used for automatic vehicle control.
In addition, the attachment of the strain sensor, which is a load sensor, requires almost no additional work on the wheel bearing, and therefore does not reduce the bearing rigidity.
Moreover, according to the wheel bearing with a sensor comprised in this way, mounting | wearing of the load sensor to a vehicle becomes easy, it can be excellent in mass productivity, and cost reduction can be aimed at.

In the present invention, the strain generating member is formed of a ring-shaped member, and the ring-shaped strain generating member is a plurality of bolt holes of the flange of the fixed side member that are in phase with each other as the notch portion. The contact fixing part may be provided between adjacent notch parts.
In the case of this configuration, a plurality of notches having the same phase as all of the bolt holes of the flange on the fixed side member are formed in one ring-shaped strain generating member. Compared to the case of preparing a strain generating member, the number of assembly steps and the number of parts can be reduced.
In addition, since the contact fixing part in the strain generating member is provided between the adjacent notch parts, each contact fixing part is fixed by aligning each notch part with the same position as the bolt hole of the flange. It can be easily fixed at a low-rigidity position spaced apart from the bolt hole in the side member in the circumferential direction.
When the contact fixing portion is provided at the center position between the adjacent notches, the contact fixing portion can be fixed at the position having the lowest rigidity in the circumferential direction of the fixing side member, so that the strain detection sensitivity by the strain sensor is further improved.

In the present invention, the fixed side member may be an outer member, and the sensor element may be a strain gauge, and may be attached in a direction to detect a circumferential strain on the inner diameter surface of the fixed side member.
Since the strain is distorted in the circumferential direction at the same phase as the bolt hole in the fixed side member, when the strain gauge is attached as a sensor element in the direction of detecting the circumferential strain of the fixed side member, Distortion detection can be performed with higher sensitivity.

In this invention, the fixed side member may be an outer member, and the strain sensor may be provided on an inner diameter surface between double row rolling surfaces of the fixed side member. In the case of this configuration, an averaged load applied to the double-row rolling surfaces is detected, and the load can be estimated more accurately without being affected by the position of the rolling elements.

In the present invention, the opposing surfaces of the flange and knuckle of the fixed side member are brought into contact with each other at the periphery of each bolt hole via an intervening portion formed of a protrusion or a protrusion provided on the flange or knuckle. The remaining ranges of the facing surfaces may be non-contact with each other.
In the case of this configuration, the surface facing the knuckle on the flange of the fixed side member contacts the surface facing the knuckle only through the spacer or the interposed portion at the periphery of each bolt hole, and the bolt hole and the bolt hole aligned in the circumferential direction are in contact with each other. Since the facing surface between them is a non-contact surface where no frictional force acts, the deformation of the fixed side member accompanying the application of a load becomes particularly prominent at the phase portion between adjacent bolt holes. Distortion is more easily concentrated on the phase part. As a result, the strain detection sensitivity by the strain gauge is further improved.

In this invention, the estimation means may estimate a load in the vertical direction that is a direction perpendicular to the axle from the output signal of the strain sensor.
When a load is applied in a direction perpendicular to the axle, a load close to a pure radial load is applied to the wheel bearing, and therefore, a load in the same direction is applied to the rolling elements in both rows. Therefore, the outer diameter surface of the fixed member is deformed outward with respect to the load direction. Also in this case, since the amount of deformation is small at a position in the same phase as the bolt hole of the flange, the strain tends to concentrate on the notch portion of the strain generating member that is in the same phase as the bolt hole, and the sensor element measures this strain. . For this reason, this sensor-equipped wheel bearing is particularly suitable for estimating the load in the vertical direction, which is perpendicular to the axle, by the estimation means based on the output signal of the sensor element of the strain sensor.

The sensor-equipped wheel bearing according to the present invention includes an outer member in which a double-row rolling surface is formed on the inner periphery, an inner member in which a rolling surface facing the rolling surface is formed on the outer periphery, and both members. A plurality of rolling elements interposed between the opposing rolling surfaces, on the outer periphery of the fixed member of the outer member and the inner member,
In a wheel bearing that has a flange for mounting a vehicle body to be attached to a knuckle, and is provided with bolt holes in a plurality of locations in the circumferential direction of the flange to rotatably support the wheel with respect to the vehicle body.
A strain sensor in which a sensor element for measuring the distortion of the notch is attached to a strain generating member having two or more contact fixing portions and one or more notches in contact with the fixed side member. One or more are installed on the surface or the outer diameter surface, the notch is disposed at the same phase as the bolt hole of the flange of the fixed side member, and the wheel according to the output signal of the sensor element of the strain sensor The load sensor can be installed without lowering the bearing rigidity, and the force between the wheel tire and the road surface can be measured at both low and low speeds. It can be detected accurately.

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. Inner member 2 having surface 4 formed thereon, and double row rolling elements 5 interposed between rolling surfaces 3 and 4 of outer member 1 and inner member 2.
It consists of. This wheel bearing is a double-row angular contact ball bearing type, and the rolling element 5
Consists of balls and is held by the 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 in a suspension device (not shown) of the vehicle body on the outer periphery, and the whole is an integral part. Bolt holes 14 for mounting the vehicle body are provided at a plurality of locations in the circumferential direction on the flange 1a.
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. Hub wheel 9
An inner ring fitting surface 12 having a step and a small diameter is provided on the outer periphery of the inboard side end, and the inner ring 10 is fitted to the inner ring fitting surface 12. A through hole 11 is provided at the center of the hub wheel 9. The hub flange 9a is provided with press-fitting holes 15 for hub bolts (not shown) at a plurality of locations in the circumferential direction. In the vicinity of the base portion of the hub flange 9a of the hub wheel 9, a cylindrical pilot portion 13 for guiding a wheel and a brake component (not shown) protrudes toward the outboard side.
FIG. 2A shows a front view of the wheel bearing viewed from the inboard side. In addition, FIG.
A cross-sectional view taken along the line I-O-I in FIG.

One or a plurality (four in this case) of strain sensors 16 arranged in the circumferential direction as shown in FIG. 2A are provided on the inner diameter surface of the outer member 1 that is a fixed side member. . Above 4
In this embodiment, the positions of the individual strain sensors 16 are four locations, that is, upper left, upper right, lower left, and lower right in the drawing. As shown in FIG. 2B, the strain sensor 16 includes a strain generating member 17 having two or more contact fixing portions 17a and one or more cutout portions 17b in contact with the inner diameter surface of the outer member 1. The sensor element 18 measures the distortion of the notch 17b of the strain generating member 17.

Here, as shown in the enlarged side view of FIG. 2B, the strain generating member 17 is formed in a substantially arc shape that is long in the circumferential direction along the outer member 1, and projects to the outer peripheral side of the arc at both ends thereof. A pair of contact fixing portions 17a, 17a is formed. One notch 17b is formed at the center of the strain generating member 17 so as to open to the outer peripheral side of the arc, and the sensor element 18 is attached to the inner surface of the notch 17b. The sensor element 18 is composed of, for example, a resistance wire strain gauge,
It is affixed in a direction to detect the circumferential distortion of the inner diameter surface of the outer member 1, that is, the distortion along the arc of the distortion generating member 17. In addition, a semiconductor strain gauge may be used as the sensor element 18.

The installation position of the strain sensor 16 is a position between the rolling surfaces 3 and 3 in both rows on the inner diameter surface of the outer member 1 as shown in FIG. 1, and as shown in FIG. The notch portion 17b is positioned in the same phase as the bolt hole 14 in the vehicle body mounting flange 1a of the outer member 1.

These strain sensors 16 are connected to the outer member 1 by the contact fixing portion 17a of the strain generating member 17.
Fixed to. The contact fixing portion 17a is fixed to the outer member 1 by distorting the bolt 21 inserted from the outer peripheral side of the outer member 1 into the bolt insertion hole 20 provided in the outer member 1 in the radial direction. Bolt hole 22 provided in the contact fixing portion 17a of the generating member 17 (FIG. 2B)
It is performed by screwing and fastening, but may be bonded and fixed with an adhesive. A gap is formed between the strain generating member 17 and the outer member 1 at a portion other than the contact fixing portion 17a. When the bolt insertion hole 20 is provided, a seal structure (not shown) is preferably provided so that moisture or the like does not enter the bearing.

The strain generating member 17 is preferably a member that does not undergo plastic deformation at the maximum expected value of the acting force between the wheel tire and the road surface. As a material of the strain generating member 17, in addition to steel,
Metal materials such as copper, brass, and aluminum can be used.

Further, the outer member 1 is provided with a wiring hole (not shown) for drawing the wiring of the sensor element 18 to the outside. This wiring hole may be provided in the vicinity of the installation portion of each sensor element 18, or the wiring of each sensor element 18 may be gathered at one place and drawn out from one wiring hole. Each sensor element 18 is preferably covered with a protective cover.

In this embodiment, as the axial position of the strain sensor 16 on the inner diameter surface of the outer member 1,
The position between the rolling surfaces 3 and 3 in both rows is selected, but the position between the seal 7 and the rolling surface 3 on the outboard side, or between the seal 8 and the rolling surface 3 on the inboard side. You may install the distortion sensor 16 in a position. Further, instead of installing the strain sensor 16 on the inner diameter surface of the outer member 1, the outer member 1
The strain sensor 16 may be installed on the outer diameter surface.

The sensor elements 18 of these strain sensors 16 are connected to the estimation means 19. Estimating means 19
Is means for estimating the acting force between the tire of the wheel and the road surface based on the output signal of the sensor element 18 in the strain sensor 16. The estimating means 19 has a relation setting means (not shown) in which the relation between the acting force between the wheel tire and the road surface (for example, the acting force in the vertical direction) and the output of the sensor element 18 is set by an arithmetic expression or a table. Then, from the output of the sensor element 18, an acting force having a corresponding value in the relationship setting means is output. The relationship between the sensor output of the relationship setting means and the acting force is determined and set in advance by a test or simulation.

When a load acts between the tire of the wheel and the road surface, the inner member 2 which is a rotating side member of the wheel bearing.
Also, a load is applied to the outer member 1 that is a fixed member via the rolling elements 5. At this time, the position of the same phase as the bolt hole 14 provided in the flange 1a of the outer member 1 is fixed to the knuckle in the suspension device of the vehicle body by the bolt, so that it hardly deforms and is in the same phase as the bolt hole 14. The positions on both sides that are separated from the position in the circumferential direction are deformed. The deformation is transmitted to the strain generating member 17 installed on the inner diameter surface of the outer member 1, and the strain generating member 17 is deformed. The strain of the strain generating member 17 is measured by the sensor element 18.
At this time, the strain generating member 17 is deformed according to the radial deformation of the fixed portion of the outer member 1 where the strain generating member 17 is fixed, but the strain generating member 17 is attached to the most deformed portion in the radial direction. The strain of the strain generating member 17 increases, and a slight strain of the outer member 1 that is a fixed member can be detected by the strain sensor 16.
Further, the strain generating member 17 is provided with a notch 17b, and the rigidity of the portion of the notch 17b is reduced. Therefore, a strain larger than the strain of the outer member 1 appears in the strain generating member 17. Further, a slight distortion of the outer member 1 can be accurately detected by the sensor element 18. Since the acting force between the wheel tire and the road surface is estimated by the estimating means 19 from the output signal of the sensor element 18, the acting force between the wheel tire and the road surface can be accurately determined regardless of whether the vehicle is stationary or at a low speed. The detected load can be used for automatic vehicle control.
Further, since the strain sensor 16 as a load sensor is attached with little additional work to the wheel bearing, the bearing rigidity is not lowered.
Moreover, according to the wheel bearing with a sensor comprised in this way, mounting | wearing of the load sensor to a vehicle becomes easy, it can be excellent in mass productivity, and cost reduction can be aimed at.

FIG. 3 is an explanatory view of the deformation of the outer member 1 when the vertical load Fz is applied between the wheel tire and the road surface. In this case, since a load close to a pure radial load is applied to the wheel bearing, a load in the same direction is applied to the rolling elements 5 in both rows. Therefore, the outer diameter surface of the outer member 1 is deformed outward as indicated by an arrow in FIG. In addition, the length of the arrow in the figure shows the magnitude | size of deformation. Also in this case, the deformation amount is small at the position in the same phase as the bolt hole 14 of the flange 1a, and the deformation amount is large at the fixing position of the strain generating member 17 spaced from the bolt hole 14 in the circumferential direction. Distortion tends to concentrate at the same phase position. For this reason, the distortion tends to concentrate on the notch 17c of the strain generating member 17 to which the sensor element 18 is attached. In this wheel bearing with sensor, the direction perpendicular to the axle is determined by the output signal of the sensor element 18. It is particularly suitable for the estimation means 19 to estimate the vertical load Fz.

Further, as described above, since the outer member 1 is distorted in the circumferential direction at the same phase as the bolt hole 14, the sensor element 16 made of a strain gauge is arranged in the circumferential direction of the outer member 1 as in this embodiment. When it is pasted in the direction in which the distortion is detected, the distortion of the outer member 1 by the distortion sensor 16 can be detected with higher sensitivity.

In this embodiment, one or more (here, four) strain sensors 16 are connected to the outer member 1.
Is provided at the axial position between the rolling surfaces 3 and 3 in both rows on the inner diameter surface of the rolling surface 3 in both rows.
That is, the load averaged is detected, and the load can be estimated more accurately without being influenced by the position of the rolling element 5.

FIG. 4 shows another embodiment of the present invention. In this embodiment, in the embodiment shown in FIGS. 1 to 3, the strain generating member 17 of the strain sensor 16 is formed of a ring-shaped member. In the ring-shaped distortion generating member 17, the vehicle body mounting flange 1 a in the outer member 1 is used.
A plurality of (in this case, four) cutout portions 17b having the same phase as all of the bolt holes 14 are formed. Further, the contact fixing portion 17a is formed between adjacent cutout portions 17b and 17b, preferably at a central position. The fact that the sensor element 18 is provided in the notch portion 17b and that the contact fixing portion 17a of the strain generating member 17 is fixed to the inner diameter surface of the outer member 1 with the bolts 21 is the same as that of the strain sensor 16 in the previous embodiment. Same as the case. in this case,
Since the strain generating member 1 is a ring-shaped member, it may be fixed to the inner diameter surface of the outer member 1 by press-fitting and bonding. The configuration of the wheel bearing is the same as that of the previous embodiment.

In this embodiment, a plurality of notches 17b having the same phase as all of the bolt holes 14 of the flange 1a in the outer member 1 are formed in one ring-shaped strain generating member 17, so that each bolt Compared to the previous embodiment in which a plurality of strain generating members 17 are prepared corresponding to the holes 14, the number of assembly steps and the number of parts can be reduced.
Further, since the contact fixing portion 17a in the strain generating member 17 is provided between the adjacent notches 17b and 17b, each notch 17b is aligned at the same phase as the bolt hole 14 of the flange 1a. Thus, each contact fixing portion 17a can be easily fixed at a low rigidity position spaced apart from the bolt hole 14 in the outer member 1 in the circumferential direction. Adjacent notch 17b
, 17b, the contact fixing portion 17a can be fixed at a position having the lowest rigidity in the circumferential direction of the outer member 1, so that the strain detection sensitivity of the strain sensor 16 is further improved. To do.

FIG. 5 shows still another embodiment of the present invention. In this sensor-equipped wheel bearing, in the embodiment of FIG. 1, the opposing surfaces of the flange 1a of the outer member 1 and the knuckle 23 of the suspension device of the vehicle body are ring-shaped at the periphery of each bolt hole 14 of the flange 1a. The spacers 24 are in contact with each other, and the remaining areas of the facing surfaces are not in contact with each other. Instead of interposing the spacer 24, an interposition part including a protrusion may be provided on the facing surface of the flange 1 a or the knuckle 23, and this interposition part may be brought into contact with the opposing surface. When providing the interposition part, the shape of the interposition part is, for example, a ring shape similar to the spacer 24. Other configurations are the same as those in the embodiment of FIG.

In the case of this embodiment, the surface of the flange 1a of the outer member 1 facing the knuckle 23 is
Only at the periphery of each bolt hole 14 is a knuckle 23 via a spacer (or interposition part) 24.
Since the opposing surface between the bolt hole 14 and the bolt hole 14 aligned in the circumferential direction is a non-contact surface where no frictional force acts, the deformation of the outer member 1 due to the application of the load is adjacent. Matching bolt hole 1
4 and the bolt hole 14 are particularly prominent at the phase portion, and the distortion is more likely to be concentrated at the phase portion of the bolt hole 14. As a result, the strain detection sensitivity of the strain sensor 16 is further improved.

It is sectional drawing of the bearing for wheels with a sensor concerning one Embodiment of this invention. (A) is the front view which looked at the wheel bearing with a sensor from the inboard side, (B) is the expansion side view of a distortion sensor. It is explanatory drawing of a deformation | transformation of the outward member accompanying the application of a vertical direction load. It is the front view which looked at the bearing for wheels with a sensor concerning other embodiments of this invention from the inboard side. It is sectional drawing of the bearing for wheels with a sensor concerning other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Outer member 1a ... Body mounting flange 2 ... Inner member 3, 4 ... Rolling surface 5 ... Rolling element 14 ... Bolt hole 15 ... Press-fit hole 16 ... Strain sensor 17 ... Strain generating member 17a ... Contact fixing | fixed part 17b ... notch 18 ... sensor element 19 ... estimation means 23 ... knuckle 24 ... spacer

Claims (7)

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 plurality of rolling elements, and a flange for mounting a vehicle body to be attached to a knuckle is provided on the outer periphery of the fixed member of the outer member and the inner member, and bolts are provided at a plurality of locations in the circumferential direction of the flange. In the wheel bearing that is provided with a hole and rotatably supports the wheel with respect to the vehicle body,
A strain sensor in which a sensor element for measuring the distortion of the notch is attached to a strain generating member having two or more contact fixing portions and one or more notches in contact with the fixed side member. One or more are installed on the surface or the outer diameter surface, the notch is disposed at the same phase as the bolt hole of the flange of the fixed side member, and the wheel according to the output signal of the sensor element of the strain sensor The wheel bearing with a sensor which provided the estimation means which estimates the action force between the tire and the road surface. 2. The strain generating member according to claim 1, wherein the strain generating member is a ring-shaped member, and the ring-shaped strain generating member has a plurality of phases that are in phase with all the bolt holes of the flange of the fixed-side member as the notch portion. The sensor-equipped wheel bearing is provided between the adjacent notch portions. The sensor-equipped wheel bearing according to claim 2, wherein the contact fixing portion is provided at a central position between adjacent notch portions. In any one of Claims 1 thru | or 3, The said fixed side member is an outward member,
The sensor element is a strain gauge, and is a sensor-equipped wheel bearing attached in a direction to detect a circumferential distortion of an inner diameter surface of the fixed-side member. In any one of Claims 1 thru | or 4, The said fixed side member is an outward member,
The strain sensor is a sensor-equipped wheel bearing provided on an inner diameter surface between double row rolling surfaces of the fixed side member. In any one of Claims 1 thru / or 5, the mutually opposing surface of the flange and knuckle of the above-mentioned fixed side member is interposed via the spacer or the interposition part which consists of the projection provided in the above-mentioned flange or knuckle. A wheel bearing with sensor, which is brought into contact with the periphery of each of the bolt holes and in which the remaining ranges of the facing surfaces are not in contact with each other. 7. The sensor-equipped wheel according to claim 1, wherein the estimating means estimates a load in a vertical direction that is a direction perpendicular to an axle from an output signal of the strain sensor. bearing.

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