JP2007212389A - Load measuring device for rolling bearing unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure in which not only a load in the axial direction or moment about the axis in the longitudinal direction but also a radial load in the longitudinal direction can be determined only by facing an encoder 17 to sensors 18a<SB>1</SB>, 18a<SB>2</SB>, 18b<SB>1</SB>and 18b<SB>2</SB>in the radial direction. <P>SOLUTION: The characteristics of first and second characteristic changing sections 19 and 20 disposed in the encoder 17 vary alternately in the circumferential direction and at the same pitch, and the phases of the characteristic changes vary in the opposite direction to each other in the axial direction. A computing unit determines the radial load in the longitudinal direction, the axial load acting between both raceway rings, and the moment about the axis in the longitudinal direction based on the phase difference existing among output signals from respective sensors 18a<SB>1</SB>, 18a<SB>2</SB>, 18b<SB>1</SB>and 18b<SB>2</SB>. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  A load measuring device for a rolling bearing unit which is an object of the present invention is used to obtain a load applied between a stationary side race ring and a rotary side race ring which are combined in a relatively rotatable manner via a plurality of rolling elements. To do. Further, the obtained load is used for ensuring the running stability of a vehicle such as an automobile.

  For example, automobile wheels are rotatably supported by a rolling bearing unit such as a double-row angular type rolling bearing unit with respect to a suspension device. In order to ensure the running stability of the automobile, for example, as described in Non-Patent Document 1, an antilock brake system (ABS), a traction control system (TCS), and an electronically controlled vehicle stability A vehicle travel stabilization device such as a control system (ESC) is used. In order to control such various vehicle running stabilization devices, signals such as the rotational speed of the wheels and the acceleration in each direction applied to the vehicle body are required. In order to perform higher-level control, it may be preferable to know the magnitude of a load (for example, one or both of a radial load and an axial load) applied to the rolling bearing unit via a wheel.

  In view of such circumstances, Patent Document 1 discloses a radial applied to a rolling bearing unit based on the revolution speed of a pair of balls constituting a rolling bearing unit which is a double-row angular ball bearing unit. An invention relating to a rolling bearing unit with a load measuring device for measuring a load or an axial load is described. In the case of the invention described in Patent Document 1, the revolution speed of the balls in each row is measured as the rotation speed of the cage that holds these balls. However, since there are gaps (pocket gaps) for enabling the balls to roll between the inner surfaces of the pockets provided in the cage and the rolling surfaces of the balls, the rows There may be a slight difference between the revolution speed of the ball and the rotational speed of the cage. When a deviation occurs, the load measurement accuracy deteriorates by this deviation.

  Japanese Patent Application No. 2005-147642 discloses a rolling bearing based on the phase difference between the output signals of a pair of sensors arranged in the direction in which the load is applied. An invention for measuring the magnitude of the load applied to the unit is disclosed. 11 to 14 show the structure of the first prior invention disclosed in the above application. In the structure according to the first invention, as shown in FIG. 11, the wheel is supported and fixed (coupled and fixed) to the inner diameter side of the outer ring 1 which is a stationary race ring that does not rotate while being supported by the suspension device. A hub 2 that is a rotation side raceway is rotatably supported via a plurality of rolling elements 3 and 3. An encoder 4, 4 a is externally fixed to the intermediate part of the hub 2, and a pair of sensors is provided between the rolling elements 3, 3 arranged in a double row at the axially intermediate part of the outer ring 1. 5, 5 (5a, 5a) are provided in a state in which the respective detection units are close to and opposed to the outer peripheral surfaces of the encoders 4, 4a, which are the detection surfaces. Note that a magnetic detection element such as a Hall IC, a Hall element, an MR element, or a GMR element is incorporated in the detection unit of the sensors 5 and 5 (5a and 5a).

  In the case of the structure shown in FIGS. 12 to 13, the encoder 4 is made of a permanent magnet. On the outer peripheral surface of the encoder 4 which is a detection surface, portions magnetized in the N pole and portions magnetized in the S pole are alternately arranged at equal intervals in the circumferential direction. The boundary between the part magnetized in the N pole and the part magnetized in the S pole is inclined by the same angle with respect to the axial direction of the encoder 4, and the inclination direction with respect to the axial direction of the encoder 4 is The axial directions are opposite to each other at the intermediate portion. Therefore, the portion magnetized in the N pole and the portion magnetized in the S pole have a “<” shape with the axially middle portion protruding (or recessed) most in the circumferential direction.

  The positions where the detection parts of the sensors 5 and 5 face the outer peripheral surface of the encoder 4 are the same with respect to the circumferential direction of the encoder 4. In other words, the detection parts of the sensors 5 and 5 are arranged on the same virtual plane including the central axis of the outer ring 1. Further, in the state where the axial load is not applied between the outer ring 1 and the hub 2, the axial direction intermediate portion between the portion magnetized in the N pole and the portion magnetized in the S pole is related to the circumferential direction. The installation positions of the members 4, 5, and 5 are regulated so that the most protruding part (the part in which the tilt direction of the boundary changes) is exactly at the center position between the detection parts of the sensors 5 and 5. is doing. In the case of the structure shown in FIGS. 12 to 13, since the encoder 4 is made of a permanent magnet, it is not necessary to incorporate a permanent magnet on both the sensors 5 and 5 side.

  In the case of the load measuring device of the rolling bearing unit according to the first aspect of the invention configured as described above, when an axial load acts between the outer ring 1 and the hub 2, the output signals of the sensors 5, 5 change. Out of phase. That is, in the neutral state where an axial load is not applied between the outer ring 1 and the hub 2 and the outer ring 1 and the hub 2 are not relatively displaced, the detecting portions of the sensors 5 and 5 are It is opposed to the solid lines a and b in FIG. 13A, that is, the portion that is shifted from the most protruding portion by the same amount in the axial direction. Accordingly, the phases of the output signals of the sensors 5 and 5 coincide as shown in FIG.

  On the other hand, when a downward axial load acts on the hub 2 to which the encoder 4 is fixed in FIG. 13A (the outer ring 1 and the hub 2 are relatively displaced in the axial direction), The detectors of both sensors 5 and 5 are opposed to the portions of the broken lines B and B in FIG. 13A, that is, the portions different in axial displacement from the most protruding portion. In this state, the phases of the output signals of the sensors 5 and 5 are shifted as shown in FIG. Further, when an upward axial load is applied to the hub 2 to which the encoder 4 is fixed as shown in FIG. 13A, the detecting portions of both the sensors 5 and 5 are connected to the chain line hatch shown in FIG. , C, that is, the deviation in the axial direction from the most projecting portion opposes different portions in the opposite direction. In this state, the phases of the output signals of the sensors 5 and 5 are shifted as shown in FIG.

  As described above, in the case of the load measuring device of the rolling bearing unit according to the first aspect of the invention, the action of the axial load applied between the outer ring 1 and the hub 2 is such that the phase of the output signals of the sensors 5 and 5 is the same. It shifts in the direction according to the direction. Further, the degree to which the phase of the output signals of the sensors 5, 5 is shifted by this axial load (displacement amount) increases as the axial load increases. Therefore, the presence or absence of a phase shift between the output signals of the sensors 5 and 5 and, if there is a shift, the axial load acting between the outer ring 1 and the hub 2 based on the direction and magnitude thereof. The direction and size of action can be determined.

  In the case of the load measuring device for the rolling bearing unit according to the first aspect of the invention, a magnetic metal plate as shown in FIG. 14 may be used as the encoder 4a that is externally fitted and fixed to the intermediate portion of the hub 2. it can. Slit-like through holes 6a and 6b and column portions 7a and 7b are alternately arranged at equal intervals in the circumferential direction on the outer peripheral surface of the encoder 4a, which is the detection surface. The through holes 6a and 6b and the column portions 7a and 7b are inclined by the same angle with respect to the axial direction of the encoder 4a, and the inclined direction with respect to the axial direction is bounded by the intermediate portion in the axial direction of the encoder 4a. Are in opposite directions. That is, the encoder 4a is formed with through holes 6a and 6a inclined in the same direction in the predetermined direction with respect to the axial direction in one half of the axial direction, and in the opposite direction to the predetermined direction in the other half of the axial direction. The through holes 6b and 6b inclined by the same angle are formed.

  On the other hand, the pair of sensors 5a and 5a is installed between the rolling elements 3 and 3 arranged in a double row at the axially intermediate portion of the outer ring 1, and the detection portions of both the sensors 5a and 5a are provided. It is made to face and oppose the outer peripheral surface of the encoder 4a. The positions where the detection parts of both the sensors 5a and 5a face the outer peripheral surface of the encoder 4a are the same in the circumferential direction of the encoder 4a. A rim portion 8 that is located between the through holes 6a and 6b and continues to the entire circumference in a state where an axial load does not act between the outer ring 1 and the hub 2 includes the sensors 5a and 5a. The installation positions of the members 4a, 5a, and 5a are regulated so as to exist at the center position between the detection units. In the case where the simple encoder 4a made of a magnetic material is used, a permanent magnet is incorporated on both the sensors 5a and 5a.

Even when the encoder 4a made of a simple magnetic material as described above is used, whether or not there is a phase shift between the output signals of the sensors 5a and 5a as in the case of using the encoder 4 made of a permanent magnet. If present, the direction and magnitude of the axial load acting between the outer ring 1 and the hub 2 can be determined based on the direction and magnitude.
If the encoder is configured in an annular shape, the side surface in the axial direction of the encoder is a detection surface, and the detection portions of the pair of sensors are opposed to the detection surface in a state shifted in the radial direction, the above It is also possible to determine the displacement in the radial direction between the outer ring 1 and the hub 2 and thus the radial load applied between the outer ring 1 and the hub 2. However, Japanese Patent Application No. 2005-147642 does not specifically disclose a structure for obtaining both an axial load and a radial load.

  In Japanese Patent Application No. 2005-267552, the axial load applied between the outer ring 1 and the hub 2 is determined between the central axis of the outer ring 1 and the central axis of the hub 2 with a structure as shown in FIGS. An invention obtained from the inclination is described. In the case of the structure of the second prior invention, slit-like through-holes 6 and 6 are formed at equal intervals in the circumferential direction in the cylindrical portion 9 provided in the front half of the encoder 4b made of a magnetic metal plate. Yes. Each of these through-holes 6 and 6 has a linear shape that is inclined with respect to the axial direction of the cylindrical portion 9. A pair of sensors 5b and 5c are supported at two positions on the inner peripheral surface of the bottomed cylindrical cover 10 which are fitted and fixed to the inner end portion of the outer ring 1 on the diametrically opposite side. In the case of the structure shown in FIGS. 15 to 18, it is intended to determine the axial load applied in the width direction of the vehicle to the contact portion (ground surface portion) between the tire 12 constituting the wheel 11 and the road surface 13. Therefore, one sensor 5b is supported and fixed on the inner peripheral surface of the upper end portion of the cover 10, and the other sensor 5c is supported and fixed on the inner peripheral surface of the lower end portion of the cover 10.

  In addition, in a state where the central axis of the outer ring 1 and the central axis of the hub 2 (the encoder 4b fitted and fixed to the inner end of the hub 2) coincide with each other, the detecting portions of the sensors 5b and 5c The positions facing the outer peripheral surface of 4b are the same positions with respect to the axial direction of the encoder 4b. Therefore, in the neutral state in which the central axis of the outer ring 1 and the central axis of the hub 2 coincide with each other, the phases of the detection signals of the sensors 5b and 5c coincide with each other (no phase difference occurs).

  For example, FIG. 17 shows a case where the phases of the detection signals of the sensors 5b and 5c with respect to the change in the characteristics of the detection surface of the encoder 4b are opposite to each other (phase difference = 180 degrees). ing. For this purpose, for example, the sensors 5b and 5c are installed in opposite directions, the directions of the permanent magnets to be incorporated in the sensors 5b and 5c (directions of S and N poles) are reversed, or a processing circuit Or electrical processing. Alternatively, at the moment when the detection part of one sensor 5 b faces the through hole 6, the detection part of the other sensor 5 c is made to face the portion between the adjacent through holes 6 and 6. In any case, when no load is applied between the outer ring 1 and the hub 2, as shown in FIG. 17, the detection parts of the sensors 5b and 5c are all covered by the encoder 4b. Scan the center of the detection surface. In this state, the detection signals of both sensors 5b and 5c are in opposite phases, the phase difference is 180 degrees, and the phase difference ratio (phase difference B / 1 period A) is 0.5. In the illustrated example, when the phase difference ratio B / A is 0.5, this indicates that the axial load is zero. When the phase difference ratio B / A is larger than 0.5, the axial load is acting in a predetermined direction. When the phase difference ratio B / A is smaller than 0.5, the axial load is in the predetermined direction. Represents acting in the opposite direction.

  That is, when a moment is applied between the outer ring 1 and the hub 2 and the central axes of the outer ring 1 and the hub 2 are not matched, the phases of the detection signals of the sensors 5b and 5c are shifted from each other (phase difference). Occurs). For example, when a counterclockwise moment as indicated by an arrow in FIG. 15 is applied to the hub 2 based on an axial load applied to the ground contact surface portion, the phase of the detection signal of the one sensor 5b is neutral. The phase of the detection signal of the other sensor 5c is delayed (or advanced) from the neutral state. As a result, a phase difference is generated between the detection signals of both the sensors 5b and 5c.

  In FIG. 18, an axial load is applied from the left side of FIG. 16, and the encoder 4b is tilted counterclockwise as shown exaggeratedly in the lower left part of FIG. 18 due to the moment based on this axial load. It shows a case where the upper part of the encoder 4b rotates in the left direction and the lower part rotates in the right direction, respectively. In this case, the detection units of the sensors 5b and 5c are displaced in the opposite directions with respect to the width direction of the detection surface of the encoder 4b, so that a phase difference is detected between the detection signals of the sensors 5b and 5c. Will occur. For example, the detection signal of the sensor 5b changes in the direction in which the phase is delayed, and the detection signal of the sensor 5c changes in the direction in which the phase advances. For this reason, the phase difference and the phase difference ratio (B / A) existing between the detection signals of both the sensors 5b and 5c become small. When the axial load acts in the reverse direction and the encoder 4b tilts in the reverse direction, the phase difference and the phase difference ratio (B / A) increase.

Between the phase difference between the detection signals of the two sensors 5b and 5c and the inclination angle between the central axis of the outer ring 1 and the central axis of the hub 2 generated as described above, and the inclination angle theta ₆ holes 6,6, the pitch P of the rolling elements 3, 3 arranged in double rows, defined by the geometrical factors of the diameter or the like of the cylindrical portion 9, predetermined relationship (first relationship ) Accordingly, if an equation or map representing the first relationship is stored in a memory in a calculator (not shown) that processes the detection signals of the sensors 5b and 5c, the phase difference B (phase difference ratio B) is stored. / A) to determine the tilt angle. Further, there is a certain relationship (second relationship) between the magnitude of the inclination angle and the magnitude of the moment, which is determined by the moment rigidity of the wheel bearing rolling bearing unit. This second relationship is obtained not only by calculation based on the elastic contact theory widely known in the field of rolling bearing units, but also by experiments. Accordingly, if an equation or a map representing the second relationship is stored in the computing unit, the moment can be obtained based on the tilt angle.

Further, between the magnitude of this moment and the axial load applied in the width direction of the vehicle to the contact portion (grounding surface portion) between the tire 12 constituting the wheel 11 and the road surface 13, the turning radius of the wheel 11, etc. There is a certain relationship (third relationship) that is geometrically determined by. Therefore, if the formula or map representing the third relationship is stored in the memory in the arithmetic unit, the axial load can be obtained based on the moment. The axial load thus obtained is equivalent to the load generated on the contact surface between the road surface 13 and the wheel 11 (tire 12).
Japanese Patent Application No. 2005-256752, which discloses the invention as described above, does not disclose a structure for obtaining both an axial load and a radial load.

  On the other hand, Japanese Patent Application No. 2004-370407 discloses a specific structure for obtaining both displacement in the axial direction and displacement in the radial direction (both axial load and radial load). Yes. FIG. 19 shows an example of a structure for obtaining the displacement (load) in both directions disclosed in Japanese Patent Application No. 2004-370407. In the case of the structure according to the third aspect of the present invention, each of the annular detection surfaces existing on one side surface in the axial direction of the encoder 4d for obtaining the displacement in the radial direction is one in the radial direction of the encoder 4d. The characteristic portions for detection 14 and 14 which are inclined in the direction are provided. Further, in the axial half of the cylindrical detection surface existing on the outer peripheral surface of the encoder 4c for measuring the displacement in the axial direction (the left half of FIG. 19B), Inclined characteristic portions 15 and 15 for detection are provided. On the other hand, the detected characteristic parts parallel to the axial direction of the encoder 4c are respectively connected to the other half part in the axial direction of the detected surface of the encoder 4c (the right half part in FIG. 19B). 15a and 15a are provided.

  In the case of the structure of the third prior invention in which such encoders 4d and 4c are incorporated, among the three sensors in which the respective detection parts are opposed to the respective characteristic parts for detection 14, 15, 15a, the shaft The direction and magnitude of the phase shift of the output signals of the remaining two sensors are obtained on the basis of the moment when the output signals of the sensors facing the detected characteristic portions 15a and 15a that are parallel to the direction change. Further, the axial and radial loads are determined based on the direction and magnitude of the phase shift.

  According to the structure of the third prior invention as shown in FIG. 19, the displacements of both the load in the axial direction and the load in the radial direction can be obtained. However, it may still be difficult to install in a limited space, such as a portion between double row rolling elements constituting a wheel bearing rolling bearing unit of a small automobile. In particular, since the size of this space in the axial direction is often limited, it is difficult to adopt a structure in which the detected surface of the encoder and the sensor are opposed to each other in the axial direction in order to obtain the displacement (load) in the radial direction. There are cases.

  In view of such circumstances, in Japanese Patent Application No. 2005-125029, as shown in FIGS. 20 to 21, the detectors of three or four sensors 5 d to 5 g are provided on the outer peripheral surface of the encoder 4 a made of a magnetic metal plate. A structure is disclosed in which not only the load in the axial direction but also the load in the radial direction can be obtained only by making them face each other in the radial direction. Although detailed description is omitted, according to the structure of the fourth prior invention, the three or four sensors 5d to 5d caused by the relative displacement between the outer ring 1 and the hub 2 (see FIGS. 11 and 15). Based on the phase difference between the output signals of 5 g, not only the load in the axial direction but also the load in each radial direction is obtained. However, in the case of the fourth prior invention, it is effective when the displacement of the encoder 4a can be assumed to be only the displacement in the three translational directions, but when the displacement due to the inclination angle based on the moment occurs. In order to detect the synthesized value, an error occurs. For example, when an axial moment in the front-rear direction acts on the encoder 4a, a phase difference occurs in the detection signals of the sensors 5d and 5f (5g) arranged with a phase difference of 90 degrees with respect to the circumferential direction of the encoder 4a. However, it cannot be separated whether this is caused by the above-mentioned axial moment in the longitudinal direction or the radial load in the longitudinal direction.

JP 2005-31063 A Motoo Aoyama, “Red Badge Super Illustrated Series / A book that shows the latest mechanics of cars”, p. 138-139, p. 146-149, Sangensha Co., Ltd./Kodansha Co., Ltd., December 20, 2001

  In view of the circumstances as described above, the present invention can determine not only the axial load or the moment about the axis in the front-rear direction but also the radial load in the front-rear direction only by causing the encoder and sensor to face each other in the radial direction. Invented to realize a load measuring device for a rolling bearing unit.

The load measuring device for a rolling bearing unit according to the present invention includes a rolling bearing unit and a load measuring device.
Of these, the rolling bearing unit is present on the stationary bearing ring that does not rotate even in use, the rotating bearing ring that rotates in use, and the circumferential surfaces of the stationary bearing ring and the rotating bearing ring that face each other. And a plurality of rolling elements provided between the stationary side track and the rotating side track.
Further, the load measuring device is provided at a portion that rotates and displaces together with the rotation side raceway or the rotation side raceway, and concentrically with a portion that rotates and displaces together with the rotation side raceway or the rotation side raceway. An encoder, a sensor device supported by the stationary-side raceway and having a detection unit opposed to an outer peripheral surface that is a detection surface of the encoder, and a calculator.
The encoder includes first and second detected surfaces provided at two positions on the outer peripheral surface that are axially distant from each other. They change alternately in the circumferential direction and at the same pitch. At least the phase of the characteristic change of the first detected surface is gradually changed in a state different from the second detected surface with respect to the axial direction.
The sensor device includes at least first to third sensors. Of these, the detection part of the first sensor is opposed to the upper end part or the lower end part of the first detection surface, and the detection part of the second sensor is the second detection surface. Of the first sensor, the same as the detection unit of the first sensor, the detection unit of the third sensor is the same as the detection unit of the first sensor of the first detected surface. Opposite the opposite end.
Further, the arithmetic unit is configured to apply a radial load in the front-rear direction acting between the two race rings based on a phase difference existing between the output signals of the first to third sensors, and these It has a function of obtaining a load or moment of at least one of an axial load acting between the two race rings and a moment about an axis in the front-rear direction.

Further, when carrying out the present invention, as described in claim 2, in addition to the first to third sensors, a fourth sensor is provided, and the detection portion of the fourth sensor is connected to the second sensor. It can also be made to oppose the edge part on the same side as said 3rd sensor among detection surfaces. In this case, based on the phase difference existing between the output signals of the first to fourth sensors, the arithmetic load is applied to the axial load and the front-rear direction acting between both stationary and rotating raceways. A function for obtaining a load or moment of at least one of the moments around the axis and a radial load in the front-rear direction is provided.
Further, when the invention described in claim 2 as described above is carried out, as described in claim 3, the arithmetic unit has a position existing between the output signals of the first to fourth sensors. Based on the phase difference, it is also possible to provide a function for obtaining a displacement amount based on a moment around the vertical axis (vertical axis).
Furthermore, when carrying out the present invention, preferably, as described in claim 4, the rolling bearing unit is configured to support and fix the stationary side bearing ring to the suspension device and to support and fix the wheel to the rotation side bearing ring. This is a rolling bearing unit for supporting wheels. The computing unit has a function of calculating a load or moment acting between the stationary side raceway and the rotation side raceway based on the relative displacement amount between the stationary side raceway and the rotation side raceway. Give it.

In the case of the load measuring device of the rolling bearing unit according to the present invention configured as described above, the encoder and the sensor act only between the radial bearing and the stationary bearing ring and the rotating bearing ring. A radial load in the front-rear direction, an axial load acting between the two races, and a moment about the axis in the front-rear direction are obtained. In addition, the moment about the vertical axis can be obtained as required.
First, the radial load in the front-rear direction can be obtained based on the phase difference existing between the output signals of the first and third sensors. That is, when the radial load is applied, the encoder is displaced in the front-rear direction with respect to the two sensors. Since these two sensors are opposed to the upper and lower ends of the outer peripheral surface of the encoder in the radial direction, the phase of the output signal of one of these sensors is advanced and the phase of the output signal of the other sensor is delayed. The phase difference between the output signals of both sensors changes. Therefore, the radial load can be obtained based on this phase difference.
Further, with respect to the axial load and the moment about the longitudinal axis, by using the output signals of the first and third sensors, the second prior invention shown in FIGS. It is obtained in the same way as the case.
Further, the moment about the vertical axis is obtained based on the phase difference existing between the output signals of the first and second sensors.
Even in the case of a small-sized rolling bearing unit, the space in the radial direction (vertical direction) is relatively easy to secure. Therefore, the present invention provides, for example, a portion between double-row rolling elements that constitute a rolling bearing unit for supporting a wheel of a small automobile. It is effective as a structure that can be installed in a limited space.

[First example of embodiment]
FIGS. 1-7 has shown the 1st example of embodiment of this invention corresponding to Claims 1-4. The load measuring device of the rolling bearing unit of this example is configured by incorporating the load measuring device 16 in a double row rolling bearing unit for supporting wheels. Among these, the structure of the rolling bearing unit is the same as the structure according to the previous invention shown in FIGS. 11 and 15 described above. On the other hand, the load measuring device 16 includes an encoder 17 that is externally fitted and fixed to the axially inner end of the hub 2 that is a rotating side race, and the axially inner end of the outer ring 1 that constitutes the rolling bearing unit. Four sensors 18a ₁ , 18a ₂ , 18b ₁ , 18b ₂ supported by a cover 10 attached to the opening and an arithmetic unit (not shown) are provided.
Of these, the encoder 17 is made of a magnetic metal plate such as a mild steel plate, and is provided with first and second characteristic changing portions 19 and 20 at a portion near the tip of the outer peripheral surface which is a detection surface (closer to the inner half in the axial direction). It is supported and fixed concentrically with the hub 2 at the inner end of the hub 2 constituting the rolling bearing unit. Both the characteristic changing portions 19 and 20 are formed by forming a plurality of through holes 21a and 21b each having a slit shape at equal intervals in the circumferential direction.

  The first characteristic changing unit 19 of the two characteristic changing units 19 and 20 is a half half of the detected surface in the width direction (the right half of FIG. 1 and the lower half of the encoder 17 shown in FIG. 7). In addition, the phase of the characteristic change is provided so as to gradually change at a predetermined angle in a predetermined direction with respect to the width direction of the detected surface. On the other hand, the second characteristic changing unit 20 has a phase of characteristic change in the other half of the detected surface in the width direction (the left half of FIG. 1 and the upper half of the encoder 17 shown in FIG. 7). Is provided in a state of gradually changing at the same angle as the predetermined angle in a direction opposite to the predetermined direction with respect to the width direction of the detected surface. For this reason, in the case of this example, among the through holes 21a and 21b, the through holes 21a and 21a constituting the first characteristic changing portion 19 and the second characteristic changing portion 20 are constituted. The through holes 21b and 21b are inclined at the same angle in the opposite direction to the axial direction of the encoder 17. The through holes 21a and 21a constituting the first characteristic changing portion 19 and the through holes 21b and 21b constituting the second characteristic changing portion 20 are continuous as shown in FIG. Alternatively, they may be formed independently of each other as in the case of the first prior invention shown in FIG.

A total of four sensors 18a ₁ , 18a ₂ , 18b ₁ , 18b ₂ are provided at two positions on the upper and lower ends of the detection surface. That is, two sensors 18a ₁ and 18a ₂ are disposed above the upper end of the encoder 17, and the remaining two sensors 18b ₁ and 18b ₂ are disposed below the lower end. Of the two sensors provided at both positions, one of the sensors 18a ₁ and 18b ₁ is set as the first characteristic changing unit 19 and the other sensor 18a ₂ and 18b _{2 is set as} the detecting unit. The second characteristic changing unit 20 is opposed to the second characteristic changing unit 20. The detecting portions of the sensors 18a ₁ , 18a ₂ , 18b ₁ , 18b ₂ are not subjected to external force, and the outer ring 1 and the hub 2 are in a neutral state (center axes coincide with each other and axial displacement also occurs. The first characteristic changing portion 19 or the second characteristic changing portion 20 is opposed to the central portion in the width direction.

In the case of this example in which the sensors 18a ₁ , 18a ₂ , 18b ₁ , 18b ₂ and the encoder 17 are incorporated as described above, detection signals of these sensors 18a ₁ , 18a ₂ , 18b ₁ , 18b ₂ are sent. The arithmetic unit to be operated has the following functions, and the axial load Fy applied between the outer ring 1 and the hub 2 constituting the rolling bearing unit and the axis in the front-rear direction (indicated by arrows in FIGS. 1 and 3). D) A moment Mx, a radial load Fx in the front-rear direction, and a moment Mz about the vertical axis are obtained.
First, the case where the axial load Fy and the moment Mx about the axis in the front-rear direction are obtained will be described.

  As is apparent from the description of the second prior invention made with reference to FIG. 16, the axial load Fy applied to the contact portion between the tire 12 and the road surface 13 in the width direction of the vehicle is between the outer ring 1 and the hub 2. In addition, it is added as a composite value of the axial load (pure axial load) and the moment Mx about the longitudinal axis. The encoder 17 translates in the direction of the central axis between the outer ring 1 and the hub 2 based on the pure axial load. At the same time, the encoder 17 tilts in a direction in which the central axis and the central axis of the outer ring 1 do not coincide with each other based on the moment Mx about the longitudinal axis. Due to the inclination based on the moment Mx, the displacement amount of the encoder 17 in the axial direction of the outer ring 1 differs between the upper end portion and the lower end portion of the encoder 17.

First, in order to obtain the moment Mx about the longitudinal axis, the displacement amount δ _Hy of the upper end portion and the displacement amount δ _{Ly of the} lower end portion of the encoder 17 are obtained. The displacement is measured in the same manner as in the case of the first prior invention shown in FIGS. That is, the displacement amount δ _{Hy at} the upper end is obtained based on the phase difference existing between the output signals of the _two sensors 18a ₁ and 18a ₂ arranged above the upper end of the encoder 17. Similarly, the displacement amount δ _Ly of the lower end is obtained based on the phase difference existing between the output signals of the _two sensors 18b ₁ and 18b ₂ arranged below the lower end of the encoder 17. In this way, if the displacement amounts δ _Hy and δ _Ly of the upper and lower ends of the encoder 17 with respect to the axial direction of the outer ring 1 are known, the following formula (1) is used to determine the pureness of the hub 2 relative to the outer ring 1. Axial displacement δ _Ty can be obtained.
δ _Ty = (δ _Hy + δ _Ly ) / 2 −−− (1)
Further, the inclination of the central axis of the encoder 17 with respect to the central axis of the outer ring 1 is calculated from the displacements δ _Hy and δ _{Ly of the} upper and lower ends and the radius r of the outer peripheral surface of the encoder 17 by the following equation (2). An angle θ ₁₇ is obtained.
θ ₁₇ = (δ _Hy −δ _Ly ) / 2r −−− (2)

Between the displacement amount δ _{Ty in the} pure axial direction and the inclination angle θ ₁₇ obtained in this way and the axial load Fy applied between the outer ring 1 and the hub 2, for example, as shown in FIG. There is a certain relationship (not necessarily a linear function as shown in FIG. 2). Such a relationship can be obtained not only by mathematical processing based on the elastic contact theory widely known in the field of rolling bearings but also by experiments. Therefore, if the relationship between the displacement amount δ _{Ty in the} pure axial direction and the inclination angle θ ₁₇ and the axial load Fy is obtained in advance and incorporated in software installed in the computing unit, each sensor Based on the output signals 18a ₁ , 18a ₂ , 18b ₁ , 18b ₂ , the axial load Fy is obtained. In this case, whether the axial load Fy is obtained based on the displacement amount δ _Ty in the pure axial direction, obtained based on the inclination angle θ ₁₇ , or based on both (for example, from both It is also possible to average the required values).

Next, the case where the radial load Fx in the front-rear direction is obtained will be described. In order to obtain the radial load Fx in the front-rear direction, a displacement amount δx in the front-rear direction of the encoder 17 with respect to the outer ring 1 (the cover 10 fixed to the outer ring 1) is measured. The displacement amount δx in the front-rear direction is obtained based on the phase difference existing between the output signals of the pair of upper and lower sensors facing the upper and lower ends of the same characteristic changing portion. This point will be described based on the output signals of the pair of upper and lower sensors 18a ₂ and 18b ₂ in which the respective detection units are opposed to the upper and lower ends of the second characteristic changing unit 20. The same applies to the case based on the output signals of the pair of upper and lower sensors 18a ₁ and 18b ₁ in which the respective detection units are opposed to the upper and lower ends of the first characteristic changing unit 19.

As long as the relationship between the second characteristic changing unit 20 and the two sensors 18a ₂ and 18b ₂ is seen, as shown in FIGS. 3 to 6, the phase of the characteristic change of the detected surface is only in one direction with respect to the axial direction. It can be considered that the encoder 17a changing (in a straight line) is detected by a pair of upper and lower sensors 18a ₂ and 18b ₂ . In this case, when no load or moment is applied between the outer ring 1 and the hub 2 in any direction, the detecting portions of the sensors 18a ₂ and 18b ₂ are as shown in FIG. In addition, since the center position of the second characteristic changing unit 20 is scanned, the phases of the output signals of both the sensors 18a ₂ and 18b ₂ substantially coincide with each other (in the illustrated case, a preset half pitch is used). It is shifted by a minute).

From this state, when the axial load Fy and the moment Mx about the axis in the front-rear direction are input to the rolling bearing unit from the lower left side of FIGS. 3 and 5 (in the drawing shown in the lower left part of FIG. 5). The encoder 17a is displaced in the counterclockwise direction as indicated by an arrow in FIG. 3 while moving in parallel to the right in the lower left part of FIGS. Then, as exaggeratedly shown in the lower left part of FIG. 5, the upper end portion of the encoder 17a is inclined in the direction of displacement in the left direction and the lower end portion of the encoder 17a in the right direction. Of this inclination and the parallel movement, the parallel movement does not lead to a change in the phase difference between the output signals of the _two sensors 18a ₂ and 18b ₂ , but the inclination does not affect the two sensors 18a ₂ and 18b ₂ . This leads to a change in the phase difference between the output signals.

When a longitudinal load Fx is applied between the outer ring 1 and the hub 2, the encoder 17a is displaced in the longitudinal direction as indicated by an arrow at the upper end of FIG. Due to this displacement, as shown in FIG. 6, for example, the phase of the output signal of the upper sensor 18a ₂ is advanced, and the phase of the output signal of the lower sensor 18b ₂ is delayed, and both the sensors 18a ₂ , 18b ₂ are delayed. The phase difference between the output signals changes. In the state shown in FIG. 6, the phase difference between the output signals of both the sensors 18a ₂ and 18b ₂ is not only the longitudinal displacement of the encoder 17a based on the longitudinal load Fx but also the longitudinal direction. It also changes due to the inclination (inclination angle θ ₁₇ ) based on the moment Mx about the axis. However, the inclination angle θ ₁₇ among these is obtained by the above equation (2) based on the output signals of the four sensors 18a ₁ , 18a ₂ , 18b ₁ , 18b ₂ as described above. If the inclination angle θ ₁₇ is known, the amount of change in the phase difference between the output signals of the sensors 18a ₂ and 18b ₂ based on the moment Mx in the state shown in FIG. 6 can be found. Therefore, from the state shown in FIG. 6, except for the phase change amount based on the inclination angle theta _17, it can be taken out displacement amount in the longitudinal direction of the encoder 17a based on the load Fx of the front-rear direction.

In short, in the state shown in FIG. 6, the output signals of the sensors 18a ₂ and 18b _{2 in} the state where the displacement δ _{1 in} the front-rear direction of the encoder 17a and the tilt angle θ ₁₇ minutes δ ₂ are combined. synthesis variation [delta] _Tx of phase difference to understand between, variation [delta] ₂ of the inclination angle theta ₁₇ minutes of the retardation of this is determined by another method. Therefore, if the change amount δ ₂ of the phase difference corresponding to the inclination angle θ ₁₇ is subtracted from the combined change amount δ _Tx , the displacement amount δ ₁ (= δ _Tx −δ ₂ ) of the encoder 17a in the front-rear direction can be obtained. . If the longitudinal displacement δ ₁ is known, the longitudinal displacement δx of the hub 2 relative to the outer ring 1 can be obtained from the inclination angle θ _{21 of the} through hole 21b. Further, when the longitudinal displacement δx is known, the longitudinal load Fx applied between the outer ring 1 and the hub 2 can be obtained.

That is, there is a fixed relationship between the displacement δx and the load Fx, which is determined by the radial rigidity of the rolling bearing unit. This relationship is obtained not only by calculation based on the elastic contact theory widely known in the field of rolling bearing units, but also by experiments. Therefore, if an equation or a map representing the above relationship is stored in the computing unit, the load Fx can be obtained based on the displacement amount δx. In this case, in addition to the displacement amount δx in the front-rear direction, the displacement amount δ _{Ty in the} pure axial direction and the inclination angle θ ₁₇ are taken into account (in consideration of the influence of the displacement in the other direction). The load Fx can be obtained. Thus, if this Fx load is obtained in consideration of the influence of the displacement in the other direction, for example, the axial load Fy is applied to the rolling bearing unit, and the rigidity of the rolling bearing unit changes (highly Even under such circumstances, the load Fx in the front-rear direction can be accurately obtained without receiving crosstalk.

Next, the case where the moment Mz about the vertical axis is obtained will be described. In this case, the processing for obtaining the displacement amount δx in the front-rear direction, which is performed to obtain the load Fx in the front-rear direction, is performed by the outputs of the four sensors 18a ₁ , 18a ₂ , 18b ₁ , 18b ₂ . Perform on the signal. That is, based on the output signals of a pair of upper and lower sensors 18a ₂ and 18b ₂ each having a detection unit facing the second characteristic change unit 20, the encoder 17 in the second characteristic change unit 20 portion. The displacement amount δ ₂₀ in the front-rear direction is obtained. At the same time, based on the output signals of the pair of upper and lower sensors 18a ₁ , 18b ₁ with the respective detection units facing the first characteristic change unit 19, the encoder 17 in the first characteristic change unit 19 portion. A displacement amount δ ₁₉ in the front-rear direction is obtained. The method for obtaining these displacement amounts δ ₂₀ and δ ₁₉ is the same as the method for obtaining the displacement amount δ ₁ in the front-rear direction of the encoder 17a, and therefore a duplicate description is omitted.

If the moment Mz about the vertical axis does not act and the encoder 17 is translated in the front-rear direction, the displacement of the encoder 17 in the front-rear direction at the first and second characteristic changing portions 19, 20 The quantities δ ₁₉ and δ ₂₀ are equal. Then, in this case, as shown in (A) in FIG. 7 by a solid line (a state before the displacement) and a chain line (the state after the displacement), a pair of sensors 18a, upper end disposed above the encoder 17 ₁ , 18a ₂ (and a pair of 18b ₁ and 18b ₂ arranged below the lower end) and the boundary between the first and second characteristic change parts 19 and 20 (characteristic change boundary line) The phases are the same. Of course, as described above, when the axial load Fy and the moment Mx are applied, the above phases are different, but even in this case, if an arithmetic process for eliminating the influence of the axial load Fy and the moment Mx is performed, the above-described phase is performed. As long as the moment Mz about the vertical axis does not act, the phases of the detection portions of the pair of sensors 18a ₁ and 18a ₂ and the boundary portions of the first and second characteristic change portions 19 and 20 are the same.

On the other hand, when the moment Mz about the vertical axis is applied and the encoder 17 is oscillated and displaced about the vertical axis, the encoder 17 in the first and second characteristic changing portions 19 and 20 is used. There is a difference between the displacement amounts δ ₁₉ and δ ₂₀ in the front-rear direction. That is, in this case, even if the axial load Fy and the moment Mx are not applied (or even after a calculation process that eliminates the influence of the axial load Fy and the moment Mx is performed) ( As shown by the chain line (the state after displacement) in B), the difference between the displacement amounts δ ₁₉ and δ _{20 in} the front-rear direction of the encoder 17 at the first and second characteristic changing portions ₁₉ and ₂₀ is different. Occurs. From these displacements δ ₁₉ and δ ₂₀ , the swing displacement angle about the vertical axis of the hub 2 relative to the outer ring 1 based on the moment Mz is obtained by the following equation (3).
Oscillation displacement angle = (δ ₁₉ −δ ₂₀ ) / sensor distance L −−− (3)
Further, based on both displacement amounts δ ₁₉ and δ ₂₀ , the center of the detected surface of the encoder 17 (the portion between the first and second characteristic changing portions 19 and 20) in a state where the moment Mz is applied. ) Is obtained as “(δ ₁₉ + δ ₂₀ ) / 2”. If the swing displacement angle and the longitudinal displacement at the center of the detected surface are known, the longitudinal displacement at the center of the rolling bearing unit can be geometrically determined.

As described with reference to FIGS. 3 to 6, the displacement δ ₁ in the front-rear direction can be obtained based on the output signals of the pair of upper and lower sensors facing the upper and lower ends of any of the characteristic change portions. it can. However, the displacement δ ₁ in the front-rear direction obtained in this case is a combination of a pure displacement in the front-rear direction and a swinging displacement around the vertical axis. In a normal case, the moment Mz about the vertical axis that is related to the swing displacement about the vertical axis is very small and can generally be ignored. However, the possibility that the moment Mz about the vertical axis becomes so large that it cannot be ignored cannot be completely denied, such as when a user of an automobile wears a wheel whose offset amount deviates greatly from the standard.

In such a case, it was obtained only by obtaining the displacement in the front-rear direction from the phase difference existing between the output signals of a pair of sensors arranged at the upper and lower ends of either one of the characteristic changing portions. Whether the displacement is due to the load in the front-rear direction or due to the moment Mz about the vertical axis is unknown, which is an error related to measuring the load in the front-rear direction. Therefore, if there is a possibility that the moment Mz about the vertical axis is so large that it cannot be ignored, a swing displacement angle based on the moment Mz is obtained, and a correction based on the swing displacement angle is performed, and the displacement in the front-rear direction is determined. The value of the minute δ ₁ is accurately obtained, and the load Fx in the front-rear direction is obtained based on this value. Further, if necessary, the measurement accuracy of the axial load Fy is improved while taking this longitudinal load Fx into consideration (the axial load Fy is taken into account by taking into account the increase in rigidity of the rolling bearing unit based on the longitudinal load Fx). Is calculated). The moment Mz about the vertical axis can also be obtained from the swing displacement angle.

[Second Example of Embodiment]
8 to 10 show a second example of an embodiment of the present invention corresponding to claims 1 and 4. In the case of this example, the sensor 18a ₁ is omitted from the structure of the first example of the embodiment described above, and the remaining three sensors 18a ₂ , 18b ₁ , 18b ₂ are the same as in the case of this first example. Placed in position. In this example, the axial load Fy acting between the outer ring 1 and the hub 2, the moment Mx (indicated by arrows in FIG. 8) around the axis in the front-rear direction, and the radial in the front-rear direction are as described above. The load Fx is obtained. In the case of carrying out this example, it is assumed that the preload applied to the rolling elements 3 and 3 does not change. When the preload changes, the axial displacement of the relationship shown in FIG. 9, that is, the axial load Fy applied from the contact portion between the tire 12 and the road surface 13 (see FIG. 16), the outer ring 1, and the hub 2. And the ratio of the inclination angle between the central axes changes. As a result, the axial load Fy cannot be calculated based on the relationship shown in FIG. Therefore, in this example, it is a condition that the preload is constant. In the case of the first example of the above-described embodiment, even if the preload changes, each rolling element 3, based on the invention disclosed in Japanese Patent Application No. 2005-296053 (fifth prior invention), 3 is obtained. Although the fifth prior invention may be carried out in combination with the first example of the embodiment of the present invention, it is not related to the gist of the present invention, and therefore detailed explanation is omitted.

If the preload is constant and the relationship shown in FIG. 9 is established, among the three sensors 18a ₂ , 18b ₁ , 18b ₂ , a pair of sensors 18b ₁ , 18b ₂ arranged below the lower end of the encoder 17 is used. The amount of displacement determined based on the phase difference existing between the output signals of each other, that is, the amount of displacement of the hub 2 in the pure axial direction with respect to the outer ring 1, the central axis of the outer ring 1 and the above A displacement amount δy in the pure axial direction (displacement amount δ _{Ty in} the first example of the embodiment) is obtained by combining the amount of displacement of the lower end portion of the encoder 17 based on the inclination of the hub 2 and the central axis. Further, the inclination angle θ ₁₇ of the central axis of the encoder 17 with respect to the central axis of the outer ring 1 is obtained.

Hereinafter, description will be given to the specific procedure for obtaining the amount of displacement δy and the inclination angle theta _17. While the relationship shown in FIG. 9 is established when the preload is constant, the axial load Fy is generated between the output signals of the pair of sensors 18b ₁ and 18b ₂ disposed below the lower end of the encoder 17. It is determined based on the existing phase difference. That is, the preload is constant between the axial load Fy applied from the contact portion between the tire 12 and the road surface 13 and the phase difference existing between the output signals of the sensors 18b ₁ and 18b _2. As long as there is a certain relationship. This relationship can be obtained in advance and incorporated into software installed in the computing unit. Accordingly, the axial load Fy can be obtained based on the phase difference existing between the output signals of the sensors 18b ₁ and 18b ₂ . When the axial load Fy is obtained, the ratio V (= δy / θ ₁₇ ) between the pure axial displacement δy and the inclination angle θ ₁₇ can be found from FIG.

The lower end portion of the encoder 17 is based on the axial load Fy applied from the contact portion from the phase difference existing between the output signals of the pair of sensors 18b ₁ and 18b ₂ arranged below the lower end portion of the encoder 17. , That is, the combined displacement δ _TOTAL as shown in FIG. The combined displacement [delta] _TOTAL is a sum of the entire encoder 17 and the displacement δy of pure axial direction is displaced in the axial direction, and the displacement [delta] _Mx based on moment Mx around axis, the radius of the encoder 17 Is represented by δ _TOTAL = δy + r · θ ₁₇ . From this equation and the equation V = δy / θ ₁₇ , the inclination angle θ ₁₇ can be obtained. If the inclination angle θ ₁₇ is known, the pure axial displacement δy can be obtained from FIG. Further, the displacement amount δx in the front-rear direction is obtained in the same manner as in the first example of the embodiment described above, and the radial load Fx in the front-rear direction is obtained based on the displacement amount δx. For this reason, the load in two directions can be obtained together with the axial load Fy obtained as described above.

  Each embodiment shown in the drawings shows a structure using an encoder 17 made of a magnetic metal plate in which through holes 21a and 21b inclined in opposite directions are formed on the first and second detection surfaces. It was. On the other hand, as shown in FIG. 19B, the encoder to be used may be an encoder whose characteristic change boundary is inclined with respect to the axial direction only at the first detected surface portion. it can. Further, the property change of the detected surface of the encoder is not limited to the repetition of the through hole and the column as shown in the figure, but the repetition of the S pole and the N pole as shown in FIGS. Or the repetition of a recessed part and a convex part may be sufficient.

  In the case of a rolling bearing unit for supporting a wheel of an automobile, for example, the rotational speed of the wheel is measured as information for controlling the ABS. In the case of the first example of the embodiment shown in FIG. 1, the four wheels are used. In the case of the second example of the embodiment shown in FIG. The rotational speed is measured. As for the ABS control signal, it is sufficient to input the output signal of any one sensor to the controller for ABS, but the output signals of a plurality of sensors are taken into this controller and compared with each other. It can also be determined whether or not there is any abnormality in the sensor. If there are three or more sensors used to detect the rotational speed of the wheel, even if an abnormality occurs in any of the sensors, a sensor that is considered to be normal in the majority logic is selected, and control is temporarily performed by the sensor. You can also continue.

  In addition, the combined structure of the encoder and the sensor according to the above-described prior invention and the present invention measures the load applied between the stationary side raceway and the rotation side raceway. Therefore, the encoder and the sensor may be installed on the components of the rolling bearing unit, i.e., the stationary raceway and the rotary raceway, but at least one of the encoder and the sensor is You may install in rotary bodies or stationary members (not the structural member of a rolling bearing unit) other than these stationary-side and rotation-side bearing rings. That is, the encoder is installed on a rotating raceway or a rotating body coupled and fixed to the rotating raceway, and the sensor is installed on the stationary raceway or a stationary member coupled and fixed to the stationary raceway. You can also do it. For example, in the case of a rolling bearing unit for supporting a wheel of an automobile, an encoder is installed in a part of a constant velocity joint (rotating body) having a drive shaft for rotationally driving a hub, and a knuckle ( A sensor can be installed on the stationary member. By adopting such a configuration, the installation of the encoder and sensor does not require restrictions on the dimensions of the rolling bearing unit. For this reason, even with a small rolling bearing unit, it is possible to estimate the load acting between the stationary side raceway and the rotation side raceway.

  Further, when the above-described invention and the present invention are carried out, an arithmetic unit is required. This arithmetic unit may be installed in the rolling bearing unit portion or outside the rolling bearing unit. You may install as a separate body. However, if it is installed in the rolling bearing unit, characteristics such as a gain indicating the relationship between the phase ratio and the displacement and a gain indicating the relationship between the displacement and the load are given to the computing unit installed in each rolling bearing unit. Since it can be written, it is convenient from the viewpoint of correctly managing the gain that is different for each rolling bearing unit. On the other hand, when the rolling bearing unit is exposed to a harsh environment in terms of heat, vibration, etc., the computing unit should be installed in an environmentally advantageous place away from the rolling bearing unit. Is preferred. Even in this case, it is desirable to manage the computing unit and each rolling bearing unit so as to have a one-to-one correspondence. As a structure that can perform such management, an arithmetic unit is coupled to the harness derived from the sensor attached to the rolling bearing unit, and the rolling bearing unit and the arithmetic unit can be handled as one set via this harness. It can be considered to be transported between factories. By adopting such means, the computing unit can be installed in an environmentally advantageous place, and the characteristics such as gain that differ for each rolling bearing unit are written in the computing unit corresponding to each rolling bearing unit. I can. Specifically, a method is conceivable in which the computing unit is installed at a connector portion provided at the distal end of a harness in which the base end portion is coupled to each rolling bearing unit.

Sectional drawing which shows one example of embodiment of this invention. The diagram which shows an example of the relationship between the inclination angle of center axes, or an axial direction displacement, and an axial load. Sectional drawing which shows the detected part of an encoder used when calculating | requiring the radial load of the front-back direction, and a pair of upper and lower sensors. The schematic diagram which shows the positional relationship of any one characteristic change part in the state which the encoder is not displaced, and a pair of upper and lower sensors, and the phase difference which exists between the output signals of these both sensors. FIG. 5 is a schematic view similar to FIG. 4, showing a state where the encoder is displaced in the axial direction and at the same time is tilted by a moment about an axis in the front-rear direction. FIG. 5 is a schematic diagram similar to FIG. 4 showing a state in which the encoder is tilted by a moment about an axis in the front-rear direction and simultaneously displaced in the front-rear direction. The schematic diagram which shows the procedure which calculates | requires the displacement based on the moment around an up-down direction axis | shaft, and shows the state which looked at the encoder and a pair of sensor from the up-down direction. Sectional drawing which shows the 2nd example of embodiment of this invention. The diagram which shows the relationship between the ratio of an axial direction displacement and an inclination angle, and an axial load. The schematic diagram which shows the displacement condition of the encoder based on the axial load input from the contact part of a tire and a road surface. Sectional drawing which shows the 1st example of a prior invention. The perspective view of the encoder built in this 1st example. The diagram which shows the output signal of the sensor which changes with the fluctuation | variation of an axial load. The perspective view which shows another example of the encoder integrated in the 1st example of the said prior invention. Sectional drawing which shows the 2nd example of a prior invention. The schematic sectional drawing which shows the state assembled | attached between the suspension apparatus of the motor vehicle, and the wheel. The schematic diagram which shows the positional relationship of this encoder and sensor in the state which the encoder is not displaced, and the phase difference which exists between the output signals of both these sensors. FIG. 18 is a schematic view similar to FIG. 17 showing a state where the encoder is tilted by a moment about an axis in the front-rear direction. The schematic diagram which shows one example of the structure which calculates | requires the displacement of an axial direction and radial direction based on 3rd prior invention. The schematic diagram which shows the 1st example of 4th prior invention. The schematic diagram which shows the 2nd example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer ring 2 Hub 3 Rolling element 4, 4a, 4b, 4c, 4d, 4e Encoder 5, 5a, 5b, 5c, 5d, 5e, 5f, 5g Sensor 6, 6a, 6b Through-hole 7a, 7b Column part 8 Rim part 9 cylindrical portion 10 cover 11 wheel 12 tire 13 road 14 the detection characteristic unit 15,15a be detected for characteristic unit 16 load measuring device 17,17a encoder _{18a 1, 18a 2, 18b 1} , 18b 2 sensor 19 first Characteristic change part 20 2nd characteristic change part 21a, 21b Through-hole

Claims (4)

A rolling bearing unit and a load measuring device;
Of these, the rolling bearing unit is present on a stationary bearing ring that does not rotate even in use, a rotating bearing ring that rotates in use, and circumferential surfaces of the stationary bearing ring and the rotating bearing ring that face each other. A plurality of rolling elements provided between the stationary side track and the rotating side track,
The load measuring device includes an encoder provided concentrically with the rotating side raceway or a portion rotating and displacing together with the rotating side raceway, at a portion rotating and displacing together with the rotating side raceway or the rotating side raceway. A sensor device supported by the stationary side raceway and having a detection unit opposed to an outer peripheral surface which is a detection surface of the encoder, and a calculator.
The encoder includes first and second detected surfaces provided at two positions on the outer peripheral surface that are axially deviated from each other. The characteristics of these detected surfaces are related to the circumferential direction. Alternately and at the same pitch, and at least the phase of the characteristic change of the first detected surface is gradually changed in a state different from the second detected surface with respect to the axial direction,
The sensor device includes at least first to third sensors, and a detection unit of the first sensor among them is opposed to an upper end or a lower end of the first detection surface, The detection part of the second sensor faces the same end part as the detection part of the first sensor in the second detection surface, and the detection part of the third sensor is the same as the first detection part. Of the detected surface of the first sensor is opposed to the end opposite to the detection portion of the first sensor,
The arithmetic unit includes a radial load in the front-rear direction acting between the two raceways based on a phase difference existing between the output signals of the first to third sensors, and both the raceways. A load measuring device for a rolling bearing unit having a function of obtaining a load or moment of at least one of an axial load acting between wheels and a moment about an axis in the front-rear direction. In addition to the first to third sensors, a fourth sensor is provided, and the detection portion of the fourth sensor faces the end on the same side as the third sensor in the second detected surface. And
The computing unit is based on the phase difference existing between the output signals of the first to fourth sensors, and acts between the stationary and rotating raceways. Having the function of obtaining the load or moment of at least one of the axial load acting between the two races and the moment about the longitudinal axis;
The load measuring device of the rolling bearing unit according to claim 1.   The rolling according to claim 2, wherein the computing unit has a function of obtaining a displacement amount based on a moment about an axis in the vertical direction based on a phase difference existing between output signals of the first to fourth sensors. Bearing unit load measuring device.   A rolling bearing unit is a wheel bearing rolling bearing unit for supporting and fixing a stationary side bearing ring to a suspension device, and supporting and fixing a wheel to a rotating side bearing ring. The rolling according to any one of claims 1 to 3, wherein a load acting between the stationary side raceway and the rotation side raceway is calculated based on a relative displacement amount with the rotation side raceway. Bearing unit load measuring device.

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