JP2009186428A - Device for measuring state quantity of rolling bearing unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a structure permitting diversion of an encoder for a rotation speed measuring device widely used conventionally and measuring the external forces in many directions acting between an outer ring 1 and a hub 2. <P>SOLUTION: The encoders 4a, 4b are supported and fixed at the shaft-direction middle part and shaft-direction inner end of the hub 2, respectively. Ones for the rotation speed measuring device, i.e., ones of which feature change boundary of a side to be detected is made parallel with the width direction of the side to be detected are used as both the encoders 4a and 4b, respectively. The detection parts of sensors 9A<SB>1</SB>, 9B<SB>2</SB>are opposed to the sides to be detected of both the encoders 4a, 4b, respectively at least one by one. Thereby, the external forces in the many directions can be measured based on the phase difference between output signals of the respective sensors 9A<SB>1</SB>, 9B<SB>2</SB>. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The state quantity measuring device for a rolling bearing unit according to the present invention is used to measure a state quantity such as an external force acting between a stationary side bearing ring and a rotating side bearing ring constituting the rolling bearing unit. Further, the obtained state quantity is used for ensuring the running stability of a vehicle such as an automobile.

  For example, a wheel of an automobile is rotatably supported by a rolling bearing unit such as a double-row angular type with respect to a suspension device. In addition, in order to ensure the running stability of automobiles, for example, anti-lock braking system (ABS), traction control system (TCS), and electronically controlled vehicle stability control system (ESC) etc. The device is in use. In order to control such various vehicle running stabilization devices, signals representing the rotational speed of the wheels, acceleration in each direction applied to the vehicle body, and the like 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 describes an invention in which a special encoder is used to measure the magnitude of a load applied to a rolling bearing unit. FIG. 8 shows an example of a conventional structure relating to a state quantity measuring device for a rolling bearing unit that employs the same load measurement principle as the structure described in Patent Document 1. In this conventional structure, a hub 2 that rotates together with a wheel while supporting and fixing the wheel in use is fixed to a plurality of rolling elements 3 and 3 on the inner diameter side of the outer ring 1 that does not rotate while being coupled and fixed to a suspension device when used. It is rotatably supported via A preload is applied to each of the rolling elements 3 and 3 together with a contact angle of the rear combination type. In the illustrated example, balls are used as the rolling elements 3 and 3. However, in the case of an automobile bearing unit that is heavy, tapered rollers may be used instead of balls.

  Further, the inner end of the hub 2 in the axial direction (“inner” with respect to the axial direction refers to the center in the width direction of the vehicle in the assembled state in the automobile, and is the right side of FIGS. 1 and 5 to 8. 1 and FIGS. 5 to 8, which are outside in the width direction of the vehicle, are referred to as “outside” with respect to the axial direction. The same applies to the entire specification). It is supported and fixed concentrically. The encoder 4 includes an annular cored bar 5 and a cylindrical encoder body 6 made of a permanent magnet attached and fixed to the outer peripheral surface of the cored bar 5. S poles and N poles are alternately arranged at equal intervals in the circumferential direction on the inner half portion in the axial direction of the outer peripheral surface of the encoder body 6 which is a detected surface. The boundary between these S poles and N poles has a "<" shape with the central portion in the axial direction protruding most in the circumferential direction.

  Further, a pair of sensors 9a and 9b are supported and fixed inside a cover 7 made of a metal plate and having a bottomed cylindrical shape that closes the axial inner end opening of the outer ring 1 through a sensor holder 8 made of synthetic resin. is doing. In this state, the detection portions of both the sensors 9a and 9b are respectively placed close to and opposed to both halves in the axial direction of the detected surface of the encoder 4. In addition, magnetic detection elements such as a Hall IC, a Hall element, an MR element, and a GMR element are incorporated in the detection portions of both the sensors 9a and 9b.

  In the state measuring device for a rolling bearing unit configured as described above, when an axial load acts between the outer ring 1 and the hub 2, the outer ring 1 and the hub 2 are displaced relative to each other in the axial direction. Accordingly, the phase difference ratio (= phase difference / 1 period) existing between the output signals of the sensors 9a and 9b changes. This phase difference ratio takes a value commensurate with the action direction and magnitude of the axial load (the direction and magnitude of the relative displacement). Therefore, based on this phase difference ratio, the direction and magnitude of the axial load (the direction and magnitude of the relative displacement) can be determined. Note that the processing for obtaining these is performed by an arithmetic unit (not shown). For this reason, in the memory of this computing unit, an equation or a formula representing the relationship (zero point and gain) between the phase difference ratio and the relative displacement or load in the axial direction, which has been examined in advance by theoretical calculation or experiment. Remember the map.

  In the case of the above-described conventional structure, the number of sensors that make the detection portion face the detection surface of the encoder is two. On the other hand, although not shown, Patent Documents 2 to 3 and Japanese Patent Application No. 2006-345849 describe a structure in which multidirectional displacement and external force are required by setting the number of sensors to three or more. ing.

  By the way, in the rolling bearing unit state quantity measuring apparatus shown in FIG. 8 described above, the encoder 4 having a structure different from that of the rolling bearing unit rotational speed measuring apparatus widely used in the past for controlling the ABS or the like is used. I use it. That is, in the case of an encoder for a rotational speed measuring device that has been widely used conventionally, the boundary of the characteristic change of the detected surface is made parallel to the width direction of the detected surface (for example, Patent Document 4). reference). On the other hand, in the case of the encoder 4, the boundary of the characteristic change of the detected surface is inclined with respect to the width direction of the detected surface. When such an encoder 4 is actually manufactured, new costs (for design and new manufacturing equipment) are required. On the other hand, if an encoder for a rotational speed detecting device that has been widely used in the past can be used as an encoder for a state quantity measuring device, a new cost for the encoder becomes unnecessary. For this reason, it is desired that the encoder for the rotational speed measuring device can be used as the encoder for the state quantity measuring device. Furthermore, it is desired to realize a structure that requires multidirectional displacement and external force with such a structure that uses an encoder.

JP 2006-317420 A JP 2006-322928 A JP 2007-93580 A JP 2004-309342 A

  The state quantity measuring device of the rolling bearing unit of the present invention was invented in order to realize a structure in which an encoder for a rotational speed detecting device can be diverted and multi-directional displacement and external force are required in view of the circumstances as described above. It is.

The rolling bearing unit state quantity measuring apparatus of the present invention includes a rolling bearing unit and a state quantity measuring apparatus.
Of these, the rolling bearing unit has a double-row stationary raceway on the stationary peripheral surface, a stationary raceway that does not rotate during use, and a double-row rotational raceway on the rotational peripheral surface. A rotation-side raceway that rotates at times; and a plurality of rolling elements provided between the stationary-side raceways and the rotation-side raceways.
In addition, the state quantity measuring device is used with a pair of encoders that are supported and fixed directly or via other members, one at each of two positions on the rotating side raceway that are separated in the axial direction. A sensor device that is supported and fixed to a portion that does not rotate sometimes, and an arithmetic unit.
Each of the pair of encoders has a detected surface concentric with the rotation side raceway, and the characteristics of the detected surface are changed alternately and at equal intervals in the circumferential direction. At the same time, the boundaries between the different characteristic portions adjacent to each other in the circumferential direction are parallel to the width direction of the detected surface.
The sensor device includes one or more first sensors in which a detection unit is opposed to a detection surface of one encoder of the pair of encoders, and a detection unit on a detection surface of the other encoder. 1 to a plurality of second sensors facing each other. Each of these sensors changes an output signal corresponding to a change in characteristics of a portion of each of the above-described detection surfaces facing its detection unit.
The computing unit is configured to detect relative displacement between the stationary side raceway and the rotation side raceway, based on the phase difference existing between the output signals of the sensors, and the stationary side raceway and the rotation side. It has a function of calculating at least one kind of state quantity among external forces acting between the races.

  In carrying out the present invention as described above, for example, the structure as described in claim 2, that is, the stationary side raceway is an outer race having a double row outer raceway on the inner peripheral surface, and the rotation side The bearing ring is a hub having double-row inner ring raceways on the outer peripheral surface, and the one encoder is supported and fixed at a portion between a pair of rolling element rows at an intermediate portion in the axial direction of the hub. It is possible to adopt a structure that supports and fixes these at the axial end of the hub.

  In the state measuring device of the rolling bearing unit of the present invention configured as described above, as a pair of encoders, encoders for rotational speed measuring devices that have been widely used conventionally, An encoder in which the boundary of the characteristic change is parallel to the width direction of the detected surface can be used. This eliminates the need for new costs for both encoders. Further, in the case of the present invention, a pair of encoders supported and fixed at two positions separated in the axial direction among the rotating side races, that is, a pair that can be displaced in different directions with respect to the stationary side races. Use the encoder. Therefore, based on the phase difference between the output signals of the sensors opposed to the detection surfaces of both encoders, the multidirectional relative displacement between the stationary side raceway and the rotation side raceway, A multidirectional external force acting between the stationary side raceway and the rotation side raceway is required.

[First example of embodiment]
1 and 2 show a first example of an embodiment of the present invention. Also in the case of this example, as in the case of the conventional structure shown in FIG. 8 described above, the wheel is supported and fixed on the inner diameter side of the outer ring 1 that does not rotate in the state of being coupled and fixed to the suspension device when used. The hub 2 that rotates together with it is rotatably supported via a plurality of rolling elements 3 and 3. A preload is applied to each of the rolling elements 3 and 3 together with a contact angle of the rear combination type. In this example, in the three-dimensional orthogonal coordinate system composed of the x axis, the y axis, and the z axis orthogonal to each other, the y axis is the central axis of the outer ring 1, the z axis is the vertical axis, and the x axis is the front and rear. The following description will be given as the direction axis.

In the case of this example, encoders are respectively provided between a pair of rolling element rows (between rows) and an inner end portion (shaft end) in the axial direction of the hub 2 at an intermediate portion in the axial direction of the hub 2. 4a and 4b are fitted and fixed concentrically with the hub 2. At the same time, the detection units of the sensors (9A ₁ , 9A ₂ , 9A ₃ ) (9B ₁ , 9B ₂ , 9B ₃ ) supported and fixed to the outer ring 1 are provided on the detection surfaces of the encoders 4a, 4b. Three each are close to each other.

  Among the above-described components, the encoders 4a and 4b are formed of an annular core metal 5a and 5b that is externally fixed to the hub 2 by an interference fit, and an annular portion that constitutes the core metal 5a and 5b. It consists of an encoder body 6a, 6b made of a permanent magnet and attached to the side surface. An axially outer side surface of the encoder body 6a constituting one (between) encoder 4a and an inner side surface of the encoder body 6b constituting the other (shaft end) encoder 4b, each of which is a detected surface. , S poles and N poles are alternately arranged at equal intervals in the circumferential direction. The boundaries between the S pole and the N pole, which are different characteristic portions, are parallel to the width direction (radial direction) of the surface to be detected. The encoders 4a and 4b have the same pitch and phase in the circumferential arrangement of the S and N poles provided on the detected surface.

2 (A) shows three detection sensors, each of which is a first sensor, with the detection surface of the encoder (4a) on one side (between rows) facing each detection surface. Sensors 9A ₁ , 9A ₂ , 9A _3, and (B) are the detection surface of the encoder (4b) on the other side (shaft end) and the respective detection units facing this detection surface. FIG. ₃ is a projection view of _three sensors 9B ₁ , 9B ₂ , and 9B ₃ that are _second sensors as viewed from the right side (+ y side) in the axial direction of FIG. Therefore, in the case where the sensors 9A ₁ , 9A ₂ , 9A ₃ are located on the back side of the detected surface (A), these sensors 9A ₁ , 9A ₂ , 9A ₃ are white circles, and in front of the detected surface. In (B) where the sensors 9B ₁ , 9B ₂ , 9B ₃ are located on the side, these sensors 9B ₁ , 9B ₂ , 9B ₃ are represented by black circles (even in FIGS. 3 to 4 described later). The same).

Further, the three sensors 9A ₁ , 9A ₂ , 9A ₃ existing between the rows are supported and fixed to the intermediate portion of the outer ring 1 in the axial direction, and each of the three sensor holders 10 each made of synthetic resin. Each one is embedded and supported at the tip. On the other hand, the three sensors 9B ₁ , 9B ₂ , 9B ₃ existing at the shaft end are held and fixed in a bottomed cylindrical cover 7a fixed to the inner end in the axial direction of the outer ring 1. It is embedded and supported in a sensor holder 8a made of synthetic resin. In the case of this example, in a neutral state where no external force is acting between the outer ring 1 and the hub 2, as shown in FIG. 2, of the detected surfaces of the encoders 4a and 4b, Each of the sensors (9A ₁ , 9A ₂ , 9A ₃ ) (9B ₁ , 9B ₂ , 9B ₃ ), _{one at} each of three circumferentially equidistant positions (positions of θ = 60 °, 180 °, 300 °). ) Are close to each other. The sensors (9A ₁ , 9A ₂ , 9A ₃ ) (9B ₁ , 9B ₂ , 9B ₃ ) incorporate magnetic sensing elements such as Hall ICs, Hall elements, MR elements, GMR elements, etc. Yes.

In the case of the state measuring device of the rolling bearing unit of the present example configured as described above, when an external force acts between the outer ring 1 and the hub 2 and a radial displacement occurs in the pair of encoders 4a and 4b, Accordingly, the phases of the output signals of the sensors (9A ₁ , 9A ₂ , 9A ₃ ) (9B ₁ , 9B ₂ , 9B ₃ ) are shifted. Here, this phase shift is expressed by a phase difference ratio ε (θ) obtained by dividing the phase difference by one period, and the radial displacements of the encoders 4a and 4b in the x-axis direction and the z-axis direction are respectively X and Z. Then, the phase difference ratio ε (θ) is expressed by the following equation (1).

これら（２）〜（５）式の関係より、上記各エンコーダ４ａ、４ｂのラジアル変位（ｘ_A 、ｚ_A ）、（ｘ_B 、ｚ_B ）は、それぞれ次の（６）〜（７）式により算出できる。

又、この様に各エンコーダ４ａ、４ｂのラジアル変位（ｘ_A 、ｚ_A ）、（ｘ_B 、ｚ_B ）が求まれば、上記ハブ２の中心Ｏの変位ｘ、ｚ及び傾きφ_x 、φ_z は、それぞれ次の（８）〜（１１）式により算出できる。

尚、本例の場合、上記ハブ２の中心Ｏと上記一方のエンコーダ４ａとのｙ軸方向位置は、非常に近い為、それぞれのラジアル変位（ｘ、ｚ）（ｘ_A 、ｚ_A ）は、互いにほぼ等しく（ｘ≒ｘ_A 、ｚ≒ｚ_A ）なる。この場合に、これらを互いに等しい（ｘ＝ｘ_A 、ｚ＝ｚ_A ）と取り扱っても、測定精度に実用上問題となる程度の大きな誤差は生じない。この為、上記（８）〜（９）式の様にした。但し、これら（８）〜（９）式に代えて、上記ハブ２の中心Ｏの正確なラジアル変位（ｘ、ｚ）を表す式を採用する事もできる。この式は、上記ハブ２の中心Ｏ及び上記１対のエンコーダ４ａ、４ｂの各ｙ軸方向位置と、これら両エンコーダ４ａ、４ｂの各ラジアル変位（ｘ_A 、ｚ_A ）（ｘ_B 、ｚ）との関係に基づいて導出する事ができる。何れにしても、以上の算出処理は、車体側に設置した図示しない演算器により行う。 Also, the pitch circle diameter (PCD) of the detected surfaces of the encoders 4a and 4b is d, and the number of pairs of S poles and N poles arranged on the entire circumference of each detected surface (each of the above-mentioned per revolution The number of pulses of the output signal of the sensor) is n, the axial distance (span) between the detected surfaces is L, and the radial displacement in the x-axis direction and z-axis direction of one (between rows) encoder 4a is x _A. , Z _A , and radial displacements of the other (shaft end) encoder 4b in the x-axis direction and z-axis direction are x _B and z _B , respectively. In this case, each of these radial displacements x _A , z _A , x _B , and z _B causes a phase difference ratio between the output signals of the two sensors {pulse edge time difference Δt divided by pulse period T. a value Δt / T}, and the phase difference ratio epsilon _A2-A1 between the two sensors 9A _2, 9A _1, a phase difference ratio epsilon _A2-A3 between the two sensors 9A _2, 9A _3, the two sensors 9B _2, a phase difference ratio epsilon _B2-B1 between 9B _1, the phase difference ratio epsilon _B2-B3 between the two sensors 9B _2, 9B ₃ are each based on the equation (1), the following (2) It can represent with-(5) Formula.

From the relationship of the equations (2) to (5), the radial displacements (x _A , z _A ) and (x _B , z _B ) of the encoders 4a and 4b are respectively expressed by the following equations (6) to (7). Can be calculated.

If the radial displacements (x _A , z _A ) and (x _B , z _B ) of the encoders 4a and 4b are obtained in this way, the displacement x and z and the inclinations φ _x and φ of the center O of the hub 2 are obtained. _z can be calculated by the following equations (8) to (11).

In this example, since the position in the y-axis direction between the center O of the hub 2 and the one encoder 4a is very close, the respective radial displacements (x, z) (x _A , z _A ) are They are almost equal to each other (x≈x _A , z≈z _A ). In this case, even if these are treated as being equal to each other (x = x _A , z = z _A ), a large error that causes a practical problem in measurement accuracy does not occur. Therefore, the above formulas (8) to (9) are used. However, instead of these formulas (8) to (9), a formula representing an accurate radial displacement (x, z) of the center O of the hub 2 may be employed. This equation represents the center O of the hub 2 and the y-axis direction positions of the pair of encoders 4a and 4b, and the radial displacements (x _A , z _A ) (x _B , z) of the encoders 4a and 4b. It can be derived based on the relationship. In any case, the above calculation process is performed by a calculator (not shown) installed on the vehicle body side.

In the case of the rolling bearing unit that is the subject of this example,
(1) Between the displacement x and the radial load Fx in the x-axis direction acting between the outer ring 1 and the hub 2 (2) Between the displacement z and the outer ring 1 and the hub 2 Between the acting radial load Fz in the z-axis direction (3) The y-axis direction inputted from the ground contact surface of the tire constituting the wheel acting between the inclination φ _x and the outer ring 1 and the hub 2 (4) The inclination φ _z and the z-axis rotation acting between the outer ring 1 and the hub 2 between the axial load Fy (or the moment Mx about the x-axis generated based on this axial load Fy) A predetermined relationship is established between the moment Mz and the moment Mz, which is determined by the rigidity of the subject rolling bearing unit. These predetermined relationships are obtained not only by calculation based on the elastic contact theory widely known in the field of rolling bearing units, but also by experiments (shipment tests). Therefore, if an equation or a map representing each predetermined relationship is stored in the memory of the arithmetic unit, the radial load Fx is based on the displacement x, and the radial load is based on the displacement z. the fz, the axial load Fy (moment Mx) based on the inclination phi _x, the moment Mz based on the phi _z, are determined, respectively.

In the case of the state quantity measuring device of the rolling bearing unit of the present example configured and operated as described above, as the pair of encoders 4a and 4b, respectively, those for rotational speed measuring devices widely used conventionally, In this case, the boundary of the characteristic change of the detected surface is made parallel to the width direction of the detected surface. This eliminates the need for a new design cost for the encoders 4a and 4b. In the case of this example, a pair of encoders 4a and 4b supported and fixed at two positions separated from each other in the axial direction in the hub 2, that is, a pair of pairs that can be displaced in different directions with respect to the outer ring 1. Encoders 4a and 4b are used. Therefore, as described above, between the output signals of the sensors (9A ₁ , 9A ₂ , 9A ₃ ) (9B ₁ , 9B ₂ , 9B ₃ ) opposed to the detection surfaces of both the encoders 4a, 4b Multidirectional relative displacements x, z, φ _x , φ _z between the outer ring 1 and the hub 2 and the multi-directional acting between the outer ring 1 and the hub 2 based on the phase difference ratio of External forces Fx, Fy, Fz, Mx, and Mz are obtained.

Further, as described above, in this example, in order to obtain the relative displacement and the external force, the phase difference ratio between the sensors 9A ₁ , 9A ₂ , 9A ₃ existing between the rows and the shaft end exist. It is only necessary to measure the phase difference ratio between the sensors 9B ₁ , 9B ₂ , and 9B _3, and there is no need to measure the phase difference ratio between the sensors across both sides. Therefore, the rotation angle position when assembling the encoders 4a and 4b on both sides is restricted, and the initial phase difference between the sensors across both sides is set to a predetermined size without performing the work. That's it. Therefore, the assembly can be easily performed by that amount. In the case of this example, the circumferential arrangement of the detectors of the _three sensors 9A ₁ , 9A ₂ , 9A ₃ (9B ₁ , 9B ₂ , 9B ₃ ) is set at equal intervals. Even if it is not, the above-mentioned relative displacement and external force can be obtained by correcting the equations (2) to (7) according to the specific arrangement method.

[Second Example of Embodiment]
FIG. 3 shows a second example of the embodiment of the present invention. In the case of this example, the number of sensors opposed to the detected surfaces of the pair of encoders 4a and 4b is different from that in the first example of the above-described embodiment. That is, in the case of this example, in the neutral state, of the detected surfaces of the encoders 4a and 4b, two positions on the x axis opposite to the radial direction (positions of θ = 90 degrees and 270 degrees) Each of the sensors 9A ₁ , 9A ₂ , 9B ₁ , and 9B ₂ are made to face each other.

In the case of this example configured as described above, the phase difference between the output signals of the _two sensors 9A ₁ and 9A ₂ changes as the displacement z _A in the z-axis direction occurs in one (between columns) encoder 4a. However, the phase difference between the output signals of the _two sensors 9B ₁ and 9B ₂ changes with the occurrence of the displacement z _B in the same direction in the other (shaft end) encoder 4b. On the other hand, even if a displacement y in the y-axis direction occurs in each encoder 4a, 4b, only the distance between each detection surface and each detection unit changes, and each phase difference does not change. Further, even if the displacement x in the x-axis direction occurs in each encoder 4a, 4b, the respective phase differences do not change. Accordingly, in this example, the displacements z _A and z _B of the encoders 4a and 4b in the z-axis direction can be detected based on these phase differences, so that the displacement of the center O of the hub 2 (see FIG. 1). z and the inclination φ _x about the x-axis of the hub 2 can be obtained.

尚、これら（１２）〜（１３）式中の各記号ｄ、ｎ、Ｌの意味は、上述した実施の形態の第１例の場合と同様である。
従って、これら（１２）〜（１３）式に上記両位相差比ε_A1-A2 、ε_B1-B2 を代入し、これら（１２）〜（１３）式を演算器に計算させる事により、上記ハブ２の中心Ｏの変位ｚと、このハブ２の傾きφ_x とを求められる。 Specifically, the phase difference ratio between the output signals of the _two sensors 9A ₁ and 9A ₂ existing between the columns is ε _{A1 -A2,} and the two sensors 9B ₁ and 9B ₂ existing at the shaft end are set. If the phase difference ratio between the output signals is ε _B1-B2 , the displacement z of the center O of the hub 2 and the inclination φ _{x of the} hub 2 are expressed by the following equations (12) to (13), respectively. It is represented by

The meanings of the symbols d, n, and L in the equations (12) to (13) are the same as those in the first example of the embodiment described above.
Accordingly, by substituting the two phase difference ratios ε _{A1 -A2} and ε _B1 -B2 into these equations (12) through (13) and letting the computing unit calculate these equations (12) through (13), the above hub is obtained. The displacement z of the center O of 2 and the inclination φ _{x of the} hub 2 are obtained.

Also in this example, as in the case of the first example of the above-described embodiment, the radial in the z-axis direction acting between the outer ring 1 (see FIG. 1) and the hub 2 based on the displacement z. a load Fz, based on the inclination phi _x, a y-axis direction of the axial load Fy (x-axis moment Mx) acting between the outer ring 1 and the hub 2, are determined, respectively. Other configurations and operations are the same as those in the first example of the embodiment described above.

[Third example of embodiment]
FIG. 4 shows a third example of the embodiment of the present invention. Also in the case of this example, the number of sensors opposed to the detected surfaces of the pair of encoders 4a and 4b is different from the case of the first example of the embodiment shown in FIGS. That is, in the case of this example, in the neutral state, one sensor 9A ₁ , one at each position (θ = 90 ° position) on the x-axis, of the detected surfaces of the encoders 4a and 4b. 9B ₁ are opposed to each other.

In the case of this example configured as described above, the inclination φ around the x-axis of the hub 2 (see FIG. 1) with respect to the outer ring 1 is based on the phase difference between the output signals of the two sensors 9A ₁ and 9B ₁ . _x is required. That is, in the case of this example, as the inclination φ _{x of the} hub 2 with respect to the outer ring 1 is generated, the z axis is connected to one (between rows) encoder 4a and the other (shaft end) encoder 4b. Displacements of different magnitudes with respect to the direction occur. As a result, the phase difference between the output signals of both the sensors 9A ₁ and 9B ₁ changes. On the other hand, even if displacement x occurs in the hub 2 (both encoders 4a and 4b) with respect to the outer ring 1, the phase difference does not change. Further, even if the displacement 2 in the axial direction or the inclination φ _z around the z axis occurs in the hub 2 (both encoders 4a and 4b) with respect to the outer ring 1, the distance between each detected surface and each detecting portion changes. Only the phase difference does not change. Even if the hub 2 (both encoders 4a and 4b) is displaced in the z-axis direction with respect to the outer ring 1, the phases of the output signals of the sensors 9A ₁ and 9B ₁ are the same in the same direction. Only the magnitude changes, and the phase difference does not change. Therefore, in the case of this example, based on this phase difference, the inclination φ _{x of the} hub 4 can be obtained with high accuracy (without being affected by displacement or inclination in other directions).

尚、この（１４）式中の各記号ｄ、ｎ、Ｌの意味は、前述の図１〜２に示した実施の形態の第１例の場合と同様である。
又、本例の場合も、上記ハブ２の傾きφ_x に基づいて、上記外輪１とこのハブ２との間に作用するアキシアル荷重Ｆｙ（モーメントＭｘ）を求められる。その他の構成及び作用は、前述の図１〜２に示した実施の形態の第１例の場合と同様である。 Specifically, when the phase difference ratio between the output signals of the two sensors 9A ₁ and 9B ₁ is ε _{B1 -A1} , the inclination φ _{x of the} hub 2 is obtained by the following equation (14). It is done.

The meanings of the symbols d, n, and L in the equation (14) are the same as those in the first example of the embodiment shown in FIGS.
Also, in the present embodiment, based on the inclination phi _x of the hub 2 is calculated axial load Fy (moment Mx) acting between the outer ring 1 and the hub 2. Other configurations and operations are the same as those in the first example of the embodiment shown in FIGS.

[Fourth to Sixth Embodiments]
In the first to third examples of the above-described embodiment, the pair of encoders 4a and 4b that are supported and fixed to the hub 2 are both provided with an annular detection surface. However, when practicing the present invention, as in the fourth example of the embodiment shown in FIG. 5, a pair of encoders 4c and 4d that are supported and fixed to the hub 2 are both cylindrical detection surfaces. You can also use what you have. These encoders 4c and 4d are cylindrical core bars 5c and 5d that are externally fixed to the hub 2 by an interference fit, and are made of permanent magnets and attached to the outer peripheral surface of the core bars 5c and 5d. It consists of encoder bodies 6c and 6d. S poles and N poles are alternately arranged at equal intervals in the circumferential direction on the outer peripheral surfaces of the encoder bodies 6c and 6d, which are detected surfaces, respectively. The boundary between these S poles and N poles is parallel to the width direction (radial direction) of the surface to be detected. The encoders 4a and 4b have the same pitch and phase in the circumferential arrangement of the S and N poles provided on the detected surface.

  Further, when carrying out the present invention, as in the fifth example of the embodiment shown in FIG. 6, one (between rows) of the encoder 4 a having an annular detection surface is adopted, As the other (shaft end) encoder 4d, an encoder having a cylindrical detection surface may be employed. Further, as in the sixth example of the embodiment shown in FIG. 7, one (between rows) encoder 4c is provided with a cylindrical detection surface, and the other (shaft end) encoder 4b. As an example, it is also possible to employ one having an annular surface to be detected. In the fourth to sixth examples of these embodiments, the output signals of the sensors opposed to the detected surfaces of the pair of encoders are based on the same principle as in the first to third examples of the above-described embodiments. Based on the phase difference existing between them, the relative displacement between the outer ring 1 and the hub 2 and the external force acting between the outer ring 1 and the hub 2 are obtained.

  The present invention is not limited to the above-described embodiments, and can be applied to various structures that satisfy the requirements described in the claims. For example, the rolling bearing unit is not limited to the vehicle wheel support, but may be incorporated in a rotation support portion of various industrial machines. Further, the pair of encoders may be supported and fixed at both ends in the axial direction of the rotating side race. In addition, when implementing the present invention, it is not always necessary to obtain the relative displacement between the stationary side race ring and the rotary side race ring in order to obtain the external force acting between the stationary side race ring and the rotary side race ring. Absent. That is, a function for directly calculating an external force acting between the stationary side raceway and the rotation side raceway based on the output signal of each sensor (without going through the process of obtaining the relative displacement). Can also be given.

Sectional drawing which shows the 1st example of embodiment of this invention. The projection figure which looked at a pair of encoder main body and each sensor from the same side regarding the axial direction. The figure similar to FIG. 2 which shows the 2nd example of embodiment of this invention. The figure similar to FIG. 2 which shows the 3rd example. Sectional drawing which shows the 4th example. Sectional drawing which shows the 5th example. Sectional drawing which shows the 6th example. Sectional drawing which shows an example of the conventional structure regarding the state quantity measuring apparatus of a rolling bearing unit.

Explanation of symbols

1 the outer ring 2 hub 3 rolling element 4,4a~4d encoder 5,5a~5d core metal 6,6a~6d encoder main 7,7a cover 8,8a sensor holder _{9a, 9b, 9A 1, 9A} 2, 9A 3, 9B _1, 9B _2, 9B ₃ sensor 10 sensor holder

Claims (2)

A rolling bearing unit and a state quantity measuring device;
Of these, the rolling bearing unit has a double-row stationary raceway on the stationary peripheral surface, a stationary raceway that does not rotate during use, and a double-row rotational raceway on the rotational peripheral surface. A rotation-side raceway that rotates at times, and a plurality of rolling elements provided between the respective stationary-side raceways and the respective rotation-side raceways so as to be capable of rolling, respectively.
The state quantity measuring device includes a pair of encoders that are supported and fixed directly or via other members at two positions separated from each other in the axial direction in the rotating side raceway, and in use. A sensor device supported and fixed to a non-rotating part, and an arithmetic unit;
Each of the pair of encoders has a detected surface concentric with the rotation-side raceway, and changes the characteristics of the detected surface alternately and at equal intervals in the circumferential direction, and in the circumferential direction. The boundary between adjacent characteristic parts adjacent to each other is made parallel to the width direction of the detected surface,
The sensor device includes one or more first sensors having a detection unit opposed to a detection surface of one encoder of the pair of encoders, and a detection unit opposed to a detection surface of the other encoder. 1 to a plurality of second sensors, and each of these sensors outputs an output signal corresponding to a change in characteristics of a portion of each of the detected surfaces facing its detection unit. Is to change,
Based on the phase difference existing between the output signals of the sensors, the computing unit calculates the relative displacement between the stationary side raceway and the rotation side raceway, and the stationary side raceway and the rotation side raceway. And having a function of calculating at least one state quantity of the external force acting between
State quantity measuring device for rolling bearing units.   The stationary side race ring is an outer ring having a double row outer ring raceway on the inner peripheral surface, and the rotation side race ring is a hub having a double row inner ring raceway on the outer peripheral surface. The amount of state of the rolling bearing unit according to claim 1, wherein the state is supported and fixed at a portion between the pair of rolling element rows at the portion, and the other encoder is supported and fixed at the axial end of the hub. measuring device.

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