JP2007127253A - Rolling bearing device with sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing device equipped with a sensor having versatility applicable even to a driving wheel, provided with a sensor to sense a physical quantity varying accompanied by the displacement of peripheral side faces of rotary bearing rings, capable of determining the moment load of each vehicle wheel and a parallel displacement load in the axial direction. <P>SOLUTION: The rolling bearing device 100 with a sensor is composed of a fixed bearing ring 1 having a fixation part 12 with the body side of a vehicle, rotary bearing rings 2 and 3 arranged coaxially with the fixed bearing ring 1 and having wheel mounting parts 7, rolling elements 5 installed in double rows capable of rolling between the two bearing rings 2 and 3 for making the rings rotatable relatively, and a sensor device 14 installed on the fixed bearing ring 1 for sensing a physical quantity varying accompanied by the displacement of the peripheral side faces of the rotary bearing rings 2 and 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rolling bearing device with a sensor used for rotatably supporting wheels of a vehicle such as an automobile.

2. Description of the Related Art In recent years, in the field of automobiles, various information such as loads acting on wheels and the number of rotations of wheels has been required in order to perform operation control during traveling. In order to obtain such information, it has been proposed to provide a displacement sensor and a rotation sensor in a wheel rolling bearing device to which a wheel of an automobile is attached.
As a conventionally known rolling bearing device with a sensor for a wheel, a cylindrical fixed bearing ring having a fixed portion to the vehicle body side, a radial fixed inner ring of the fixed track ring, and a wheel There is a bearing device that includes a rotating raceway having a mounting portion, and a double row rolling element provided between the raceways so as to be rotatable relative to each other (for example, , See Patent Document 1).

In this conventional bearing device, the gap between the two race rings that changes due to the displacement of the outer peripheral side surface of the rotating race ring that occurs when a load is applied to the wheel (specifically, the electrical signal that changes corresponding to this gap) ) Is provided on the fixed track ring, and a vertical load acting on the wheel is obtained based on a gap detected by the displacement sensor.
And in the said bearing apparatus, the one through-hole which penetrates the upper part of the outer peripheral wall part of a fixed bearing ring radially is formed, By inserting the said displacement sensor downward in this through-hole, the said displacement sensor These detection surfaces are arranged in a state facing the outer peripheral surface of the rotating raceway.

Japanese Patent Laid-Open No. 2001-21577 (see FIG. 8)

  The rolling bearing device with sensor described in Patent Document 1 has a simple structure in which a detection surface of a single displacement sensor set downward is opposed to a sensor ring (target) provided on the outer peripheral surface of the rotating raceway. ing. For this reason, it is possible to obtain the translational load acting in the vertical direction on the wheel based on the detection value of the displacement sensor, but the front-rear direction (see FIG. The moment load around the x axis (13), the moment load around the vertical direction (z axis in FIG. 13), and the translational load in the axial direction of the wheel (Fy in FIG. 13) are obtained from the detection value of the displacement sensor. Is impossible.

  Therefore, in order to obtain the above-described moment load and axial translational load, another displacement sensor that detects axial displacement at the shaft end face of the rotating raceway is used as a case member that closes the inner end of the fixed raceway. (See, for example, FIGS. 1 and 2 and claim 3 of Japanese Patent Application No. 2005-266482). However, the means for adding a displacement sensor for detecting the axial displacement at the shaft end surface of the rotating raceway can be employed in a bearing device for a driven wheel in which the shaft end surface of the rotating raceway is a free end. However, there is a drawback that it cannot be employed in a bearing device for a drive wheel in which a constant velocity joint of a drive shaft is connected to the shaft end surface of the rotary drive wheel. Even in the case of a bearing device for a driven wheel, there is a drawback that it is difficult to attach a sensor other than load measurement such as an ABS sensor.

  In view of such a situation, the present invention is capable of driving a wheel moment load and an axial translation load by using only a sensor that detects a physical quantity that changes in accordance with the displacement of the peripheral side surface of the rotating raceway. An object of the present invention is to provide a highly versatile rolling bearing device with a sensor that can be applied to a wheel.

  The present invention relates to a fixed bearing ring having a fixed portion with respect to the vehicle body side, a rotating bearing ring arranged coaxially with respect to the fixed bearing ring and having a wheel mounting portion, and a relative rotation of these both bearing rings. A plurality of rolling elements provided between the two race rings so as to be freely movable, and the fixed race ring to detect a physical quantity that changes in accordance with the displacement of the peripheral side surface of the rotary race ring. In the rolling bearing device with a sensor provided with the provided sensor device, the sensor device detects the physical quantities at positions separated in the axial direction on the peripheral side surface of the rotating raceway, respectively. And is connected to a control device having a calculation function for calculating a moment load acting on the wheel based on a difference between detection values detected by each of the sensor members.

In this case, the first sensor member and the second sensor member that detect a physical quantity that changes in accordance with the displacement of the peripheral side surface of the rotating raceway ring detect the physical quantity at a position separated in the axial direction on the peripheral side surface of the rotating raceway ring. Therefore, the moment load acting on the wheel can be calculated by the control device based on the difference between the detection values detected by the sensor members.
In this way, since the moment load of the wheel can be obtained only by the first and second sensor members that detect the physical quantity that changes with the displacement of the peripheral side surface of the rotating raceway, in order to measure the moment load There is no need to add a sensor to detect the axial displacement of the shaft end face of the rotating raceway. For this reason, it can be applied to a bearing device for a drive wheel to which a constant velocity joint of a drive shaft is connected, and it becomes easy to mount a sensor other than a load measurement such as an ABS sensor. A high sensor rolling bearing device is obtained.

In the rolling bearing device of the present invention, when the rotating raceway is provided with a target portion that causes a difference in detection values detected by the sensor members when the rotating raceway is displaced in the same direction in the axial direction. In addition, the sensor device can be connected to the control device having an arithmetic function for calculating an axial translational load acting on the wheel based on a difference between detection values detected by the sensor members. .
In this case, the control device to which each sensor member is connected can also calculate the axial translational load acting on the wheel based on the difference between the detection values detected by each sensor member. For this reason, since both the moment load of the wheel and the translational load in the axial direction can be calculated based on the detection values by the same sensor members, the number of sensors for load measurement can be suppressed as much as possible.

In the present invention, more specifically, as the target portion, an annular first detected portion that faces the detection surface of the first sensor member and an annular first portion that faces the detection surface of the second sensor member. A thing provided with two to-be-detected parts can be adopted.
In this case, as each said to-be-detected part, when the said rotating raceway is displaced to the same direction in an axial direction, what becomes the shape and arrangement | positioning which changes the detected value which each said sensor member detects to a positive / negative reverse direction. It is preferable to adopt.
If such a detected part is adopted, the detection value for the unit translation amount in the axial direction of the rotating raceway ring is amplified by taking the difference between the detection value of the first sensor member and the detection value of the second sensor member. As a result, the detection sensitivity of the axial displacement of the entire sensor device can be increased.

  In the present invention, more specifically, the first sensor member is disposed above and below the rotating raceway, with a first front sensor and a first rear sensor respectively disposed before and after the rotating raceway. The second sensor member may be composed of a first front sensor and a second rear sensor respectively disposed before and after the rotating raceway, and the same orbital theory. The second upper sensor and the second lower sensor respectively disposed above and below the sensor.

In this case, as will be described in detail later in the embodiment, the following are obtained from the eight detection values f _i , r _i , t _i, b _i , f _o , r _o , t _o and b _o by the above-described sensors. SFy, which is an independent variable corresponding to the translational load Fy in the y-axis direction, according to the expressions (1) to (5) of
sMz which is an independent variable corresponding to the moment load Mz around the z-axis,
sMx, which is an independent variable corresponding to the moment load Mx around the x-axis,
sFz which is an independent variable corresponding to the translational load Fz in the z-axis direction, and
sFx, which is an independent variable corresponding to the translation load Fx in the x-axis direction,
Each can be calculated.
The x axis is the horizontal direction of the wheel, the y axis is the horizontal direction (axial direction) of the wheel, and the z axis is the vertical direction of the wheel (see FIG. 13).
sFy = (f _i + r _i + t _i + b _i ) − (f _o + r _o + t _o + b _o ) (1)
sMz = −mz × kz (2)
sMx = mx × kx (3)
sFz = z _i −mx × kx (4)
sFx = x _i −mz × kz (5)

As described later, the five independent variables sFx, sFy, sFz, sMx, and sMz described above are linearly independent of Fx, Fy, Fz, Mx, and Mz that are actual loads (five component forces) acting on the wheels. There is a relationship (see FIG. 12). Therefore, once these independent variables sFx, sFy, sFz, sMx, and sMz are obtained, the quinary simultaneous linear equation with the five component forces Fx, Fy, Fz, Mx, and Mz as unknowns is solved. The component forces Fx, Fy, Fz, Mx and Mz can be calculated.
Therefore, each sensor is provided by providing an arithmetic circuit (hardware) or a control program (software) for solving the above-described equations (1) to (5) and a quinary simultaneous linear equation in the control device such as an ECU. Based on the eight detected values f _i , r _i , t _i, b _i , f _o , r _o , t _o and b _o , the actual loads Fx, Fy, Fz, Mx and Mz acting on the wheels are obtained. be able to.

In the present invention, each of the sensor members is preferably attached to one case member, and the case member is preferably attached to an inner side end portion of the fixed raceway.
In this case, since each sensor member can be attached to the fixed track ring by simply attaching a case member having each sensor member to the inner end of the fixed track ring, each sensor member is individually attached to the fixed track ring. There is no need, and there is no need to provide a through hole for mounting the sensor on the fixed race. In addition, since the sensor member can be positioned with respect to the rotating raceway by attaching the case member to the fixed raceway, the assembly is also easy in this respect.
Furthermore, in this case, each sensor member detects a physical quantity associated with the deformation behavior of the inner end portion of the rotating raceway having a larger deformation behavior with respect to the external force than the axial center portion (portion close to the bearing center) of the rotating raceway. As a result, the detection accuracy of the physical quantity can be increased.

In the present invention, sensor elements constituting each sensor member are not particularly limited, but it is preferable to employ an inductance type displacement sensor. Since such an inductance-type displacement sensor is not easily affected by geomagnetism, particularly in the case of a vehicle such as an automobile that travels with its traveling direction freely changed, control becomes unstable due to noise caused by the geomagnetism. Can be prevented.
Further, if the inductance type displacement sensor is configured by connecting a plurality of coil elements arranged in the circumferential direction having independent detection surfaces in series, the magnetic flux density generated in one displacement sensor is increased, and the target is increased. The detection sensitivity of the gap with the part can be improved.

Furthermore, in the present invention, each detected portion provided in the target portion can be constituted by an annular groove, a ridge formed along the circumferential direction of the target portion, or inclined surfaces having different inclination directions. Moreover, it can also be comprised from the cyclic | annular strip part which consists of material which has a magnetic permeability different from the surrounding structural material.
In the case of the former annular groove, ridge or inclined surface, compared to the latter annular band, there is an advantage that the processing is simple and the manufacturing cost is low. In the latter case, compared to the former, There is an advantage that the physical quantity (for example, inductance in the case of an inductance type displacement sensor) changes with respect to the unit movement amount in the axial direction, and the detection sensitivity of the physical quantity increases.

  As described above, according to the present invention, the moment load of the wheel and the translational load in the axial direction can be obtained only by the sensor that detects the physical quantity that changes with the displacement of the peripheral side surface of the rotating raceway. It is possible to provide a highly versatile rolling bearing device with a sensor that can also be applied to a vehicle.

[Overall structure of bearing device]
Hereinafter, embodiments of a rolling bearing device with a sensor according to the present invention (hereinafter, also simply referred to as “bearing device”) will be described with reference to the drawings.
FIG. 1 is a side sectional view of a bearing device according to the present embodiment, and FIG. 2 is an enlarged sectional view of a sensor portion of the bearing device. 3 is a view of the bearing device as seen from the inner side, and FIG. 4 is a view of the bearing device as seen from the inner side with a lid member 17 described later removed. In FIG. 1, the right side is the outer side (the outside of the vehicle), and the left side is the inner side (the inside of the vehicle).

As shown in FIG. 1, the bearing device 100 of this embodiment includes a cylindrical outer ring 1, an inner shaft 2 that is rotatably inserted into the outer ring 1, and an inner side end portion of the inner shaft 2. The inner ring member 3 is externally fitted to the inner ring member, the target part 4 is externally fitted to the inner side end of the inner ring member 3, and the double-row rolling elements 5 and 5 are formed of a plurality of balls arranged in the circumferential direction. These constitute a double-row angular contact ball bearing portion. The balls in each row as the rolling elements 5 and 5 are held by the holder 6 at a predetermined interval in the circumferential direction.
In the present specification, the direction along the center line C of the bearing device 100 is defined as the y-axis direction, the horizontal direction perpendicular to the paper surface is defined as the x-axis direction, and is orthogonal to the y-axis direction and the x-axis direction. The vertical direction is defined as the z-axis direction. Therefore, as shown in FIG. 13, the x-axis direction is the front-rear horizontal direction of the wheel, the y-axis direction is the left-right horizontal direction (axial direction) of the wheel, and the z-axis direction is the vertical direction.

  In the bearing device 100 of this embodiment, the outer ring 1 is a fixed race that is fixed to the vehicle body. On the other hand, the inner shaft 2, the inner ring member 3, and the target portion 4 are wheel-side rotating race rings, and the double row rolling elements 5, 5 are rotated between the fixed race ring and the rotating race rings. It is movably interposed. Thereby, the fixed raceway and the rotary raceway are arranged coaxially with each other, and the rotary raceway is rotatable with the wheels (the tire and the tire wheel shown in FIG. 13) relative to the fixed raceway.

  The inner shaft 2 constituting the rotating raceway has a flange portion 7 extending outward in the radial direction on the outer side, and this flange portion 7 serves as a mounting portion of a wheel tire wheel or a brake disc. The tire wheel or the like is attached to the flange portion 7 with a mounting bolt (not shown). The inner ring member 3 is externally fitted to a step portion formed on the inner side of the inner shaft 2, and is fixed to the inner shaft 2 by a nut 8 screwed into the inner side end portion of the inner shaft 2. The inner raceway surfaces 9, 9 of the rolling elements 5, 5 are formed on the outer peripheral surface of the inner shaft 2 and the outer peripheral surface of the inner ring member 3, respectively.

The outer ring 1 constituting the fixed raceway includes a cylindrical main body cylinder portion 11 in which outer raceway surfaces 10 and 10 of the rolling elements 5 and 5 are formed on the inner peripheral surface, and a radial direction from the outer peripheral surface of the main body cylinder portion 11. And a flange portion 12 extending outward. The flange portion 12 is fixed to a knuckle (not shown) of a suspension device that is a vehicle body side member, whereby the bearing device 100 is fixed to the vehicle body side.
The bearing device 100 according to the present embodiment uses a physical quantity that changes with the displacement of the outer peripheral side surface of the target unit 4 provided on the rotating raceway (in this embodiment, an inductance that changes due to a gap with the outer peripheral side surface of the target unit 4). A sensor device 14 for detection and a case member 15 for attaching the sensor member 14 to the outer ring 1 which is a fixed raceway ring are provided.

[Case member structure]
As shown in FIGS. 1 and 2, the case member 15 includes a short cylindrical tube member 16 and a disk-shaped lid member 17. The cylindrical member 16 is made of a cylindrical metal member that is short in the axial direction, and is fixed to the inner side end of the outer ring 1 so as to be coaxial with the outer ring 1 by a set screw 18 at an opening on one end side thereof. Yes. The lid member 17 is a member that closes the opening on the other end side of the cylindrical member 16, and prevents foreign matter from entering the inside of the bearing device 100.
The sensor device 14 for detecting a gap with the outer peripheral side surface of the target portion 4 attached to the inner side end portion of the inner shaft 2 is mounted on the inner peripheral side of the cylindrical member 16 of the case member 15.

[Structure of sensor device]
As shown in FIGS. 2 and 4, the sensor device 14 of the present embodiment includes a first sensor member 21 and a second sensor member 22 that detect gaps at positions separated in the axial direction on the outer peripheral side surface of the target unit 4, respectively. It has. In the present specification, regarding the sensor device 14 and the target unit 4, “first” means the inner side, and “second” means the outer side.
The first and second sensor members 21, 22 are inductance-type displacement sensors that detect a change in gap with the outer peripheral side surface of the target unit 4 by a change in inductance, and are separated in the axial direction on the inner peripheral side of the cylindrical member 16. The sensor ring 23 attached in two rows and a plurality of (four in this embodiment) displacement sensors 24 arranged at predetermined intervals in the circumferential direction of the sensor ring 23 are provided. Each sensor ring 23 is fixed to the flange portion 16a of the cylindrical member 16 with a set screw 26 with a cylindrical spacer 25 interposed (see FIG. 1).

The displacement sensors 24 of the first and second sensor members 21 and 22 are provided at four positions, front and rear, and upper and lower, respectively, and gaps in the x-axis direction and the z-axis direction with the outer peripheral side surface of the target portion 4 of the rotating raceway ring. It is arranged so that a change can be detected.
That is, the inner side first sensor member 21 includes a first front sensor 24f and a first rear sensor 24r disposed before and after the rotating raceway, and a first upper sensor 24t and a first upper sensor 24t respectively disposed above and below the rotating raceway. And a first lower sensor 24b. The second sensor member 22 on the outer side also includes a second front sensor 24f and a second rear sensor 24r disposed before and after the rotating raceway, and a second upper sensor 24t and a second upper sensor 24t respectively disposed above and below the rotating raceway. And a second lower sensor 24b.

  Each of these eight displacement sensors 24 (f, r, t, b) is connected in series with a pair of coil elements 27, 27 arranged in close proximity in the circumferential direction having an independent detection surface for the target portion 4. It is configured by The pair of coil elements 27, 27 are configured by winding a coil around a pair of magnetic poles 28 protruding from the inner peripheral side of the sensor ring 23. These magnetic poles 28 protrude inward in the radial direction from the sensor ring 23, and an end face (detection surface) on the inner side of the diameter faces the outer peripheral side surface of the target unit 4 with a gap in the radial direction. Has been placed.

As described above, in the bearing device 100 of the present embodiment, the first and second sensor members 21 and 22 that have the four displacement sensors 24 arranged in the front-rear direction and the upper-lower direction and are separated in the axial direction are integrally formed with the case member 15. Since the sensor unit is mounted, all the displacement sensors 24 can be attached to the outer ring 1 simply by attaching the case member 15 to the inner side end of the outer ring 1 when the bearing device 100 is assembled. For this reason, it is not necessary to attach each displacement sensor 24 to the outer ring 1 individually, and it is not necessary to provide a through hole for mounting the sensor in the outer ring 1.
Further, by attaching the case member 15 to the outer ring 1, the circumferential position and the radial position of each displacement sensor 24 with respect to the target portion 4 of the rotating raceway are positioned. There is no need for mounting, and in this respect, the assembly of the bearing device 100 is extremely easy.

Further, each displacement sensor 24 incorporated in the case member 15 has an inner side end of the rotating raceway whose deformation behavior with respect to an external force is larger than an axially central portion (portion close to the bearing center O shown in FIG. 1) of the rotating raceway. Since the gap associated with the deformation behavior of the target portion 4 located in the portion is detected, there is an advantage that the accuracy of detecting the gap is increased.
Furthermore, when the case member 15 with the sensor is attached to the inner side end of the outer ring 1, the displacement sensor 24 is disposed at a position relatively far from the flange 12 of the outer ring 1. There is also an advantage that a gap change can be detected with high accuracy in this respect.

FIG. 5A shows an example of a gap detection circuit by the sensor device 14 of the present embodiment. As shown in the figure, among the displacement sensors 24 of the sensor members 21 and 22, the sensors 24t and 24b opposite to each other in the vertical direction (upper sensor and lower sensor in FIG. 5) are connected to the oscillator 30, respectively. An alternating current having a constant period is supplied from the oscillator 30 to the sensors 24t and 24b. A synchronous capacitor 31 is connected in parallel to each sensor 24t, 24b.
In this embodiment, the output voltage (detection value) from each of the sensors 24t and 24b is determined by the differential amplifier 32 to obtain an output voltage (detection value) corresponding to the amount of displacement in the vertical direction. The temperature drift is removed. Although not shown in the drawing, the temperature drift is also removed from the sensors facing each other in the horizontal direction by taking the difference with the differential amplifier in the same manner as described above.

By the way, in the inductance type displacement sensor 24, when the inductance of the coil is L, the area of the detection surface is A, the magnetic permeability is μ, the number of turns of the coil is N, and the distance (gap) from the detection surface to the target 4 is d. The following equation (a) is established.
L = A × μ × N ² / d (a)
Accordingly, when the gap d to the target 4 changes, the inductance L of the displacement sensor 24 changes and the output voltage changes. By detecting this change in the output voltage, the target portion 4 is detected from the detection surface of the displacement sensor 24. A radial gap up to can be detected.

  And in this embodiment, since the one displacement sensor 24 is comprised by connecting a pair of coil element 27 which has the independent detection surface with respect to the target part 4 in series, as shown in FIG.5 (b). As compared with the case where one displacement sensor 27 is constituted by one coil element 27, the magnetic flux density generated is further increased, and thereby the detection sensitivity of the gap with the target unit 4 is further improved.

[Structure of the target part]
As shown in FIGS. 1 and 2, the target portion 4 is formed of a cylindrical member that is externally fitted and attached to the inner side end portion of the inner ring member 3. On the outer peripheral side surface of the target portion 4, there are an annular first detected portion 34 that faces the detection surface of the inner side first sensor member 21 (tip surface of the magnetic pole 28), and an outer side second sensor member 22. An annular second detected portion 35 is provided opposite to the detection surface. In the present embodiment, these detected portions 34 and 35 are configured by first and second annular grooves formed along the circumferential direction of the target portion 4.

As shown in FIG. 2B, the inner-side first annular groove 34 is disposed such that the outer-side groove end surface 34 a is positioned in the vicinity of the center of the detection surface A <b> 1 of the first sensor member 21. The second annular groove 35 is arranged so that the groove end surface 35a on the inner side is located in the vicinity of the center of the detection surface A2 of the second sensor member 22.
For this reason, if the target portion 4 of the rotating raceway is displaced by a distance δ in the axial direction, for example, on the inner side, the lap length in the axial direction between the first sensor member 21 and the first annular groove 34 is on the inner side. As a result, the detected value of the gap by the first sensor member 21 decreases, and on the outer side, the wrap length in the axial direction between the second sensor member 22 and the second annular groove 35 increases, and the second sensor member The detected value of the gap by 22 increases.

Similarly, if the target portion 4 of the rotating raceway is displaced to the outer side in the axial direction by a distance δ, the detected value of the gap by the first sensor member 21 on the inner side increases, and the second sensor member 22 on the outer side. The detected value of the gap due to decreases.
Thus, the target unit 4 of the present embodiment causes a difference in the detection values detected by the first and second sensor members 21 and 22 when the rotating raceway is displaced in the same direction in the axial direction. A pair of annular grooves 34 and 35 separated in the axial direction are provided on the outer peripheral side surface.

Further, as described above, these annular grooves 34 and 35 change the detected values detected by the sensor members 21 and 22 in the positive and negative directions when the rotating raceway is displaced in the same direction in the axial direction. An axial position with respect to the sensor side is set.
Accordingly, as is apparent from the calculation method of the detection value in the control device 37 described later, the difference between the detection value of the inner side first sensor member 21 and the detection value of the outer side second sensor member 22 is taken to determine the rotational trajectory. The detection value with respect to the unit translation amount in the axial direction of the wheel is amplified, whereby the detection sensitivity of the axial displacement of the entire sensor device can be increased.

In contrast to the arrangement shown in FIG. 2B, the inner-side first annular groove 34 is shifted to the outer side with respect to the detection surface A <b> 1 of the first sensor member 21, and the outer-side second annular groove 35. May be shifted from the detection surface A2 of the second sensor member 22 toward the inner side, and even in this case, the same effect as described above can be obtained.
The displacement sensors 24 constituting the first and second sensor members 21 and 22 are controlled by, for example, an ECU or the like on the vehicle body side via a signal line 36 (see FIG. 4) that passes through the lid member 17 of the case member 15. It is connected to the device 37. The output voltage (detected value) obtained from each sensor is calculated in the control device 37 by the calculation method described below, whereby the moment load and translation load acting on the wheel in each direction are obtained.

[Calculation method for each load]
Hereinafter, the load calculation method performed by the control device 37 will be described with reference to FIGS. FIG. 11 is a block diagram showing a calculation method in the control device 37.

[Definition of direction and sensor detection value]
As shown in FIG. 13, the front-rear horizontal direction of the wheel is defined as the x-axis direction, the left-right horizontal direction (axial direction) of the wheel is defined as the y-axis direction, and the vertical direction of the wheel is defined as the z-axis direction.
Further, as shown in FIG. 6, the subscript “i” is used for the detection value of the sensor on the inner side (first sensor member 21), and the subscript “o” is used for the sensor on the outer side (second sensor member 22). Is used. Further, the detection value of the front sensor is defined as “f (front)”, the detection value of the rear sensor is defined as “r (rear)”, and the detection value of the upper sensor is defined as “t (top)”. The detection value of the lower sensor is defined as “b (bottom)”.

Accordingly, the detection values of a total of eight sensors provided on the first and second sensor members 21 and 22 are defined as follows.
f _i : Detection value of the first front sensor r _i : Detection value of the first rear sensor t _i : Detection value of the first upper sensor b _i : Detection value of the first lower sensor f _o : Detection value of the second front sensor r _o : detection value of the second rear sensor t _o : detection value of the second upper sensor b _o : detection value of the second lower sensor

[Independent variable (sFy) corresponding to translational load Fy in the y-axis direction]
As shown in FIG. 7B, when a translational load Fy in the y-axis direction acts on the wheel, the rotating raceway is displaced in the direction of the load, and the positions of the annular grooves 34 and 35 are shifted in the axial direction. . Therefore, as described above, the detection value of each sensor on the inner side (the output voltage in this _{embodiment) f i, r i, t} i, b it is either with increasing amount of axial movement δ to decrease The detected values f _o , r _o , t _o and b _o of the outer side sensors all increase as the axial movement amount δ increases.
Therefore, as shown in FIG. 7B, sFy calculated by the following equation (1) is adopted as an independent variable corresponding to the translational load Fy in the y-axis direction (see the calculation block B1 in FIG. 11).
sFy = (f _i + r _i + t _i + b _i ) − (f _o + r _o + t _o + b _o ) (1)
Thus, by taking the difference between the detection value of each sensor on the inner side and the detection value of each sensor on the outer side, sFy with respect to the unit translation amount in the axial direction of the rotating raceway ring is amplified. The detection sensitivity of the axial displacement as a whole can be increased.

[X-axis direction displacement and z-axis direction displacement]
As shown in the calculation block B2 in FIG. 11, in the x-axis direction, the detected value of the displacement in the x-axis direction is determined by the difference between the detected value f of the front sensor and the detected value r of the rear sensor. The detected value t and the detected value b of the lower sensor are used as a detected value of displacement in the z-axis direction.
Since the output of the front and rear sensors and the output of the upper and lower sensors are affected by the temperature in the same direction by the same amount, the temperature drift is eliminated by taking the difference as described above.

In the present invention, since the displacement sensors 24 are arranged on the inner side and the outer side, the detected value of the x-axis direction displacement and the detected value of the z-axis direction displacement at each of the inner side and the outer side positions as shown below. Is obtained.
Detection values of the x-axis direction displacement at the inner side x _i = _{f i} -r _i
Detected value of displacement in the z-axis direction on the inner side z _i = −t _i + b _i
Detection values of the x-axis direction displacement at the outer side x _o = _{f o} -r _o
Detected value of displacement in the z-axis direction on the outer side z _o = −t _o + b _o

[Independent variable (sMz) corresponding to moment load Mz around z-axis]
Next, as shown in FIG. 8, a pure moment state in which only the moment load Mz about the z-axis acts is assumed.
In this case, the axial distance from the bearing center O to the detection position of the inner sensor (first sensor member 21) is L _i , and the axial direction from the bearing center O to the detection position of the outer sensor (second sensor member 22). If the distance is L _o , the detected value corresponding to the moment load Mz around the z-axis can theoretically be obtained by mz calculated by the following equation. This mz is obtained when θ is sufficiently small. Should be consistent with x _i .
mz = L _i × tan θ
= L _i × tan ((x _i -x _o ) / (L _i -L _o ))

However, actually, since the annular grooves 34 and 35 are formed in the target portion 4, as shown in FIG. 10A, mz does not coincide with x _i . FIG. 10 (a), when an acting only z axis of the moment load Mz, a line graph showing the relationship between the detection value of the Mz and mz and x _i, thus, mz and x _The slopes of the straight line graphs of the detected values of _i do not match.
Therefore, as shown in FIG. 10C, in order to make these inclinations coincide, a correction coefficient kz obtained by dividing the inclination of the _xi line by the inclination of the mz line is introduced. Therefore, as shown in the following equation (2), by multiplying the above-described mz by the correction coefficient kz, an independent variable sMz corresponding to the moment load Mz around the z-axis is obtained (calculation blocks B3 and B4 in FIG. 11). reference). The minus (−) on the right side is for making the sign coincide with other independent variables (such as sFy and sMx described later).
sMz = −mz × kz (2)

[Independent variable (sMx) corresponding to moment load Mx around x-axis]
The x-axis direction and the z-axis direction have a relationship obtained by coordinate conversion by 90 degrees. Therefore, the independent variable sMx corresponding to the moment load Mx around the x axis can be calculated by the following equation (3) based on the same concept as in the case of sMz.
sMx = mx × kx (3)
Incidentally, kx in the above formula (3) is a correction factor introduced in the same spirit as kz, the slope of z _i straight is a correction coefficient obtained by dividing the slope of mx line (FIG. 10 (b) and (Refer FIG.10 (c)).

[Independent variable (sFz) corresponding to the translational load Fz in the z-axis direction]
[Independent variable (sFx) corresponding to translation load Fx in the x-axis direction]
Next, as shown in FIG. 9, it is assumed that the translational load Fx in the x-axis direction acts together with the moment load Mz around the z-axis.
In this case, the detected value x _{i of the} displacement in the x-axis direction on the inner side includes the component of the independent variable sMz corresponding to the moment load Mz around the z-axis and the independent variable sFx corresponding to the translational weight Fx in the x-axis direction. Contains ingredients. Thus, the independent variable sFx corresponding to translation weighted Fx in the x-axis direction can be determined by subtracting the sMz from the _{x i.}
This also applies to the case of sFz, which is an independent variable corresponding to the translation load Fz in the z-axis direction.

Therefore, the independent variable sFz due to the translational load Fz in the z-axis direction and the independent variable sFx due to the translational load Fx in the x-axis direction can be calculated by the following equations (4) and (5), respectively (FIG. 11). (See calculation block B4).
sFz = z _i −mx × kx (4)
sFx = x _i −mz × kz (5)

FIG. 12 shows the independent variables sFx, sFy, sFz, sMx and sMz obtained by the above equations (1) to (5), and Fx, Fy, Fz, Mx and Mz which are actual loads acting on the wheels. It is a matrix figure showing the correspondence of these.
That is, Fx, Fy, Fz, Mx and Mz actually loaded on the wheel are input, and the independent variables sFx, sFy, sFz, sMx and sMz obtained by the equations (1) to (5) are output, It is a matrix of straight line graphs between these variables.

As shown in the matrix diagram of FIG. 12, only sFx has a slope with respect to Fx, and the other Fy, Fz, Mx, and Mz have no reaction. Only the corner is a line graph. Therefore, these five independent variables sFx, sFy, sFz, sMx and sMz are in a linearly independent relationship with the five component forces Fx, Fy, Fz, Mx and Mz which are actual loads acting on the wheels.
Therefore, once these independent variables sFx, sFy, sFz, sMx and sMz are obtained, by solving the five-way simultaneous linear equations with five loads Fx, Fy, Fz, Mx and Mz acting on the wheels as unknowns, The respective loads Fx, Fy, Fz, Mx and Mz can be calculated.

In the present embodiment, the control device 37 composed of an ECU or the like incorporates an arithmetic circuit (hardware) or a control program (software) that solves the above-described equations (1) to (5) and a five-way simultaneous linear equation. ing. Therefore, based on the eight detected values f _i , r _i , t _i, b _i , f _o , r _o , t _o and b _o by each sensor, the actual loads Fx, Fy, Fz, Mx and Mz can be determined.

The present invention is not limited to the above embodiment.
For example, as shown in FIG. 14A, annular belt portions 39 and 40 having a magnetic permeability larger (or smaller) than the surrounding constituent materials may be provided in the annular grooves 34 and 35 of the target portion 4. it can. For example, in the case of steel materials, such annular belt portions 39 and 40 can be formed by changing the amount of carbon contained.
Moreover, as a to-be-detected part of the target part 4, it can also be comprised not only the above-mentioned annular grooves 34 and 35 but the protrusions 41 and 42 as shown in FIG.14 (b), FIG.14 (c). It is also possible to form the inclined surfaces 43 and 44 whose inclination directions are opposite to each other. In addition, although both the inclined surfaces 43 and 44 of FIG.14 (c) have a trough shape in the junction part, it can also be set as the both inclined surface in which the junction part becomes a mountain shape.
Further, the sensor members 21 and 22 constituting the sensor device 14 may be directly attached to the outer ring 1 instead of the case member 15. Furthermore, in the above embodiment, the outer ring 1 on the outer peripheral side of the bearing device 100 is configured as a fixed bearing ring, and the inner shaft 2 and the like on the inner peripheral side are configured as rotating bearing rings. It can also be configured as a fixed raceway and the outer peripheral side as a rotary raceway.

The sensor device 14 of the present invention can employ not only an inductance type displacement sensor but also other displacement sensors as long as it is a non-contact type capable of detecting a gap.
Furthermore, the control device 37 that performs the calculation method and the sensor device 14 connected thereto can be applied not only to a rolling bearing device for a vehicle but also to a bearing device other than a vehicle such as a magnetic bearing. The control device 37 that performs the calculation method shown in FIG. 11 and the sensor device 14 that is arranged in two rows in the axial direction as a precondition for performing the calculation are various bearing devices that have a need to measure a plurality of moment loads and translation loads. Can be adopted.

  That is, the present invention provides a fixed track ring, a rotating track ring coaxially and rotatably arranged with respect to the fixed track ring, and a physical quantity that changes with displacement of the peripheral side surface of the rotating track ring. The present invention can be applied to a rolling bearing device including a sensor device provided on the fixed raceway for detection. In this case, the sensor device includes a first sensor member and a second sensor member that detect the physical quantities at positions separated in the axial direction on the circumferential side surface of the rotating raceway, and the detection values detected by the sensor members. It is only necessary to connect to a control device that performs the above-described calculation method (for example, the calculation method shown in FIG. 12) for calculating the moment load acting in the radial direction and the translational load in the axial direction based on the above.

It is side surface sectional drawing of the rolling bearing apparatus with a sensor which concerns on one Embodiment of this invention. (A) is an expanded sectional view of the sensor portion of the bearing device, and (b) is a diagram showing the positional relationship between the sensor member and the annular groove. It is the figure which looked at the same bearing device from the inner side. It is the figure which looked at the same bearing device in the state where a lid member was removed from the inner side. (A) is a circuit diagram which shows an example of the detection circuit of the gap by a sensor apparatus, (b) is function explanatory drawing of a coil element. It is a figure which shows the arrangement position of each displacement sensor, and the definition of the detected value. (A) is a graph which shows the calculation method of sFy, (b) is a figure which shows the deformation | transformation behavior of the rotating raceway by the load Fy. It is a figure which shows the deformation | transformation state of the rotating raceway in a pure moment state. It is a figure which shows the deformation | transformation state of a rotation bearing ring when a moment load and a translation load act. (A) is a line graph of mz and _{x i} in pure moment state, (b) is a line graph of mx and _{z i} in pure moment state, showing the (c) the calculation of the correction coefficient kz and kx It is a formula. It is a block diagram which shows the calculation method in a control means. It is a matrix figure which shows the correspondence of the independent variable calculated from the sensor output, and the actual load which acts on a wheel. It is a perspective view of a wheel portion showing the definition of each load with x-axis direction, y-axis direction, and z-axis direction. It is a figure which shows the modification of a to-be-detected part, (a) is a figure showing the positional relationship of a sensor member and an annular belt part, (b) is a figure showing the positional relationship of a sensor member and a protrusion, (c) is a sensor. It is a figure showing the positional relationship of a member and an inclined surface.

Explanation of symbols

1 Outer ring (fixed race)
2 Inner shaft (rotating raceway)
3 Inner ring member (rotating raceway)
4 Target part 7 Flange part (Mounting part)
12 Flange (fixed part)
Reference Signs List 14 sensor device 15 case member 21 first sensor member 22 second sensor member 24 displacement sensor 27 coil element 34 first annular groove (first detected portion)
35 Second annular groove (second detected part)
37 Controller

Claims (12)

A fixed race ring having a fixed portion with respect to the vehicle body side, a rotating race ring disposed coaxially with respect to the fixed race ring and having a wheel mounting portion, and the two race rings to be relatively rotatable. A double-row rolling element provided between the two raceways and a sensor provided on the fixed raceway for detecting a physical quantity that changes with displacement of a peripheral side surface of the rotary raceway. A rolling bearing device with a sensor comprising:
The sensor device includes first and second sensor members that respectively detect the physical quantities at positions separated in the axial direction on the peripheral side surface of the rotating raceway, and detection values detected by the sensor members are detected. A sensor-equipped rolling bearing device connected to a control device having a calculation function for calculating a moment load acting on the wheel based on a difference. When the rotating raceway is displaced in the same direction in the axial direction, a target portion that causes a difference in detection values detected by the sensor members is provided in the rotating raceway,
The said sensor apparatus is connected to the said control apparatus which has the calculation function which calculates the axial translational load which acts on the said wheel based on the difference of the detected value detected by each said sensor member. The rolling bearing device with a sensor as described. The target portion includes an annular first detected portion that faces the detection surface of the first sensor member, and an annular second detected portion that faces the detection surface of the second sensor member,
The said each to-be-detected part becomes a shape and arrangement | positioning which change the detected value which each said sensor member detects to a positive / negative reverse direction, when the said rotating raceway is displaced to the same direction in an axial direction. Rolling bearing device with sensor. The first sensor member includes a first front sensor and a first rear sensor respectively disposed before and after the rotating raceway, and a first upper sensor and a first lower sensor respectively disposed above and below the rotating raceway. Consisting of
The second sensor member includes a second front sensor and a second rear sensor respectively disposed before and after the rotating raceway, and a second upper sensor and a second lower sensor respectively disposed above and below the rotational trajectory. The rolling bearing device with a sensor in any one of Claims 1-3 comprised from these. The rolling bearing device with a sensor according to claim 4, wherein sFy calculated by the following equation (1) is an independent variable corresponding to the translational load Fy in the y-axis direction.
sFy = (f _i + r _i + t _i + b _i ) − (f _o + r _o + t _o + b _o ) (1)
However,
x-axis: front-rear horizontal direction of wheel y-axis: left-right horizontal direction (axial direction) of wheel
z axis: vertical direction of wheel f _i : detected value of first front sensor r _i : detected value of first rear sensor t _i : detected value of first upper sensor b _i : detected value of first lower sensor f _o : detection values of the second front sensor r _o: detection value of the second sensor after t _o: detected values of the second upper sensor b _o: detected values of the second lower sensor SMz calculated by the following equation (2) is an independent variable corresponding to the moment load Mz around the z axis, and sMx calculated by the following equation (3) corresponds to the moment load Mx around the x axis. The rolling bearing device with a sensor according to claim 5, which is an independent variable.
sMz = −mz × kz (2)
sMx = mx × kx (3)
However,
mz = L _i × tan ((x _i −x _o ) / (L _i −L _o ))
mx = L _i × tan ((z _i −z _o ) / (L _i −L _o ))
x _i = _{f i} -r _i
z _i = −t _i + b _i
x _o = _{f o} -r _o
z _o = −t _o + b _o
L _i : Axial distance from bearing center to detection position of first sensor member L _o : Axial distance from bearing center to detection position of second sensor member kz: Correction coefficient for independent variable sMz kx: For independent variable sMx Correction factor SFz calculated by the following equation (4) is an independent variable corresponding to the translation load Fz in the z-axis direction, and sFx calculated by the following equation (5) corresponds to the translation load Fx in the x-axis direction. The rolling bearing device with a sensor according to claim 6, wherein the rolling bearing device is an independent variable.
sFz = z _i −mx × kx (4)
sFx = x _i −mz × kz (5)   The rolling bearing device with a sensor according to any one of claims 1 to 7, wherein each sensor member is attached to one case member, and the case member is attached to an inner side end portion of the fixed race.   9. The sensor-equipped rolling bearing device according to claim 1, wherein each of the sensor members is an inductance type displacement sensor.   The rolling bearing device with a sensor according to claim 9, wherein the inductance-type displacement sensor is configured by connecting a plurality of coil elements arranged in the circumferential direction having independent detection surfaces in series.   The sensor-equipped rolling bearing device according to claim 3, wherein each of the detected parts includes an annular groove, a ridge formed along a circumferential direction of the target part, or inclined surfaces having different inclination directions.   4. The sensor-equipped rolling bearing device according to claim 3, wherein each of the detected portions includes an annular belt portion made of a material having a magnetic permeability different from that of surrounding constituent materials.

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