JP2009001201A - Quantity-of-state measuring device for rotary machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a structure easily arranging six sensors 6s<SB>1</SB>to 6s<SB>6</SB>in a provided space by devising arranged structure of the six sensors 6s<SB>1</SB>to 6s<SB>6</SB>. <P>SOLUTION: A structure is adopted which is other than having detectors in the six sensors 6s<SB>1</SB>to 6s<SB>6</SB>facing both of first and second characteristic variation parts 9 and 10 of an encoder 4 by three pieces each. For example, the structure is adopted in accord with the provided space with detectors of the two sensors 6s<SB>1</SB>and 6s<SB>2</SB>facing the first characteristic variation part 9 and detectors of remaining four sensors 6s<SB>1</SB>to 6s<SB>4</SB>face the second characteristic variation part 10 respectively. Thus the problem above is solved. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The state quantity measuring device for a rotary machine according to the present invention is a state quantity between a stationary member and a rotary member, each of which constitutes a rotary machine such as a rolling bearing unit, a relative displacement between these two members, It is used to measure the external force (load, moment) applied between these two members. Further, the obtained state quantity is used for ensuring the running stability of a vehicle such as an automobile.

  The wheel of the automobile is rotatably supported by the suspension device by a rolling bearing unit such as a double row angular type. In addition, in order to ensure the running stability of automobiles, anti-brake brake system (ABS), traction control system (TCS), and electronically controlled vehicle stability control system (ESC) etc. Is used. 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. 3 to 5 show an example of a state quantity measuring device for a rolling bearing unit that employs the same load measurement principle as that of the structure of the invention described in Patent Document 1. FIG. In this conventional structure, a plurality of hubs 2 that are rotating side race rings are rotated on the inner diameter side of an outer ring 1 that is a stationary side race ring that does not rotate even when used, while the wheels are supported and fixed during use. The rolling elements 3 and 3 are rotatably supported. A preload is applied to each of the rolling elements 3 and 3 together with contact angles that are opposite to each other (in the illustrated case, a rear combination type). In the illustrated example, a ball is used as the rolling element 3, but in the case of an automobile bearing unit that is heavy, a tapered roller may be used instead of the ball.

Also, the inner end of the hub 2 ("inner" in the axial direction means the center side in the width direction of the vehicle when assembled to the automobile, and is the right side of FIGS. 1, 3, 6 and 8. Conversely, to the automobile. In the assembled state of FIG. 1, the left side of FIGS. 1, 3, 6, and 8 is referred to as “outside” in the axial direction. The same applies to the entire specification.) The hub 2 is supported and fixed concentrically. In addition, a pair of sensors 6a ₁ and 6a ₂ are held inside a bottomed cylindrical cover 5 that closes the inner end opening of the outer ring 1, and the detection portions of both the sensors 6a ₁ and 6a ₂ are provided as described above. The encoder 4 is placed in close proximity to the outer peripheral surface, which is the detected surface.

  Of these, the encoder 4 is made of a magnetic metal plate. In the front half (axially inner half) of the encoder 4, through holes 7, 7 (first characteristic part) and column parts 8, 8 (second characteristic part) are alternately arranged in the circumferential direction and Arranged at equal intervals. The boundaries between the through holes 7 and 7 and the pillars 8 and 8 are inclined by the same angle with respect to the axial direction (width direction) of the detection surface, and the inclination direction with respect to the axial direction is determined as the detection target. The directions are opposite to each other with the axial middle portion of the surface as a boundary. Accordingly, each of the through holes 7 and 7 and each of the column portions 8 and 8 has a "<" shape with the axially intermediate portion protruding most in the circumferential direction. The outer half of the axial direction and the inner half of the axial direction of the outer peripheral surface of the encoder 4 that is the detected surface, the inclination directions of which are different from each other, are defined as the first characteristic changing unit 9. The inner half of the axial direction is the second characteristic changing unit 10. In addition, each through-hole which comprises both these characteristic change parts 9 and 10 may be formed in the mutually continuous state like illustration, and it is in the mutually independent state (each through-hole is arrange | positioned in "C" shape). ) Further, although the detection accuracy is inferior, only the boundary of one of the characteristic change parts 9 and 10 is inclined with respect to the axial direction, and the boundary of the other characteristic change part is parallel to the axial direction. You can also do it.

Each of the pair of sensors 6a ₁ and 6a ₂ includes a permanent magnet and a magnetic detection element such as a Hall IC, a Hall element, an MR element, and a GMR element that constitute a detection unit. Of these sensors 6a ₁ and 6a ₂ , the detection part of _one sensor 6a ₁ is the first characteristic change part 9 and the detection part of the other sensor 6a ₂ is the second characteristic change part 10, respectively. Closely opposed. The positions where the detection parts of these sensors 6a ₁ and 6a ₂ face both the characteristic change parts 9 and 10 are the same position (the lower end part in the illustrated example) in the circumferential direction of the encoder 4. Further, in the neutral state where an axial load does not act between the outer ring 1 and the hub 2, a portion that protrudes most in the circumferential direction at the axially intermediate portion of each of the through holes 7 and 7 and the column portions 8 and 8 ( The position where each member is installed is regulated so that the portion where the tilt direction of the boundary changes) is just at the center position between the detection parts of the sensors 6a ₁ and 6a ₂ .

In the case of the conventional structure 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 relatively displaced in the axial direction), the sensors 6a ₁ and 6a ₂ The phase at which the output signal changes is shifted. That is, in the neutral state where no axial load is applied between the outer ring 1 and the hub 2, the detecting portions of the sensors 6a ₁ and 6a ₂ are shown by solid lines A and B in FIG. That is, it faces a portion that is shifted from the most protruding portion by the same amount in the axial direction. Therefore, the phases of the output signals of the two sensors 6a ₁ and 6a ₂ coincide as shown in FIG. On the other hand, when a downward axial load is applied to the hub 2 to which the encoder 4 is fixed as shown in FIG. 5A, the detecting portions of the sensors 6a ₁ and 6a ₂ are shown in FIG. A) is opposed to the broken lines B and B, that is, the portions that are different from each other in the axial direction from the most protruding portion. In this state, the phases of the output signals of the sensors 6a ₁ and 6a ₂ 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. 5A, the detecting portions of the sensors 6a ₁ and 6a ₂ are shown in FIG. Deviations in the axial direction from the chain lines C and C, that is, from the most projecting portion are opposed to different portions in the opposite direction. In this state, the phases of the output signals of the sensors 6a ₁ and 6a ₂ are shifted in the opposite direction to the case of (B), as shown in (D) of FIG.

As described above, in the case of the conventional structure, the phases of the output signals of the sensors 6a ₁ and 6a ₂ are applied in the direction of the action of the axial load applied between the outer ring 1 and the hub 2 (the outer ring 1 and the hub 2). 2 in the direction of relative displacement in the axial direction). Further, the degree to which the phase of the output signals of the sensors 6a ₁ and 6a ₂ is shifted by this axial load (relative displacement) increases as the axial load (relative displacement) increases. Therefore, the direction of the relative displacement in the axial direction between the outer ring 1 and the hub 2 based on the presence and absence of the phase shift of the output signals of the sensors 6a ₁ and 6a ₂ and the direction and magnitude of the shift, if any. And the magnitude, and the direction and magnitude of the axial load acting between the outer ring 1 and the hub 2 are obtained.

Actually, the relative displacement and load in the axial direction are calculated based on the phase difference ratio (phase difference / 1 period) existing between the output signals of the sensors 6a ₁ and 6a _2. The calculation process is performed by an arithmetic unit (not shown). For this reason, in the memory of this computing unit, an expression or map representing the relationship 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, is stored. .

  In the case of the conventional structure described above, the encoder is made of a magnetic metal plate, the first characteristic portion provided on the detection surface of the encoder is a through hole, and the second characteristic portion is a column portion. is doing. On the other hand, the encoder is made of a permanent magnet, the first characteristic portion provided on the detection surface of the encoder is a portion magnetized to the N pole, and the second characteristic portion is a portion magnetized to the S pole. Can also be adopted. When such a configuration is adopted, it is not necessary to incorporate a permanent magnet on the pair of sensor sides.

  By the way, in the case of controlling the vehicle running state stabilizing device such as ABS, TCS, or ESC described above, either one of the above-described axial load (displacement) and radial load (displacement) ( Higher control can be achieved by using both loads (displacements) as control information than using only displacement) as control information. Furthermore, in addition to both of these loads (displacements), if the moment acting between the outer ring 1 and the hub 2 (the inclination of the central axes of the outer ring 1 and the hub 2) is used as control information, Advanced control is possible. For this reason, it is desired to realize a structure that can measure all three types of state quantities of the axial load (displacement), the radial load (displacement), and the moment (tilt).

  FIGS. 6 to 13 show an example of the structure of the prior invention relating to a state quantity measuring device for a rolling bearing unit, which was previously invented and applied for a patent in order to meet such a demand (Japanese Patent Application No. 2006-345849). . The structure of this prior invention is configured by incorporating a state quantity measuring device 12 into a rolling bearing unit 11 for supporting a wheel, which is a rotating machine. Since the structure of the rolling bearing unit 11 is the same as that of the conventional structure shown in FIG. 3 described above, the same parts are denoted by the same reference numerals, and redundant description is omitted. Further, when considering a three-dimensional coordinate system composed of an x-axis, a y-axis, and a z-axis that are orthogonal to each other, the central axis (lateral axis) of the outer ring 1 that is the stationary bearing ring that constitutes the rolling bearing unit 11. Is the y axis, the vertical axis is the z axis, and the longitudinal axis is the x axis.

The state quantity measuring device 12 includes one encoder 4 that is externally fitted and fixed to the inner end portion of the hub 2 that is the rotation side raceway, and the inner end opening portion of the outer ring 1 that constitutes the rolling bearing unit 11. 6 sensors 6a ₁ , 6a ₂ , 6b ₁ , 6b ₂ , 6c ₁ , 6c ₂ supported and fixed to the cover 5 attached to the cover 5 and an arithmetic unit (not shown). Since the structure of the encoder 4 is the same as that of the conventional structure shown in FIGS. 3 to 5 described above, the same parts are denoted by the same reference numerals, and redundant description is omitted. The six sensors 6a ₁ , 6a ₂ , 6b ₁ , 6b ₂ , 6c ₁ , 6c ₂ are each a permanent magnet and a magnetic element such as a Hall IC, Hall element, MR element, GMR element or the like constituting the detection unit. And a sensing element. These six sensors 6a ₁ , 6a ₂ , 6b ₁ , 6b ₂ , 6c ₁ , 6c ₂ are detected surfaces, which are 3 at equal intervals in the circumferential direction of the portion near the inner end of the outer peripheral surface of the encoder 4. Two each are arranged at a position facing the location. Specifically, as shown in FIG. 9, when the circumferential position (angle) θ is set, the two sensors 6a ₁ and 6a ₂ constituting the first sensor set are positioned at θ = 0 degrees. At the position of θ = 120 degrees, the two sensors 6b ₁ and 6b ₂ constituting the second sensor set, and the two sensors 6c constituting the third sensor set at the position of θ = 240 degrees. ₁ and 6c ₂ are arranged, respectively.

Then, the first characteristic changing unit which is the outer half of the detected surface in the axial direction is used as the detection unit of one of the two sensors constituting each sensor set, 6a ₁ , 6b ₁ , 6c _1. 9, the detection units of the other sensors 6a ₂ , 6b ₂ , and 6c ₂ are opposed to the second characteristic changing unit 10 that is the inner half of the detected surface in the axial direction. When no external force is applied, that is, when the outer ring 1 and the hub 2 are in a neutral state (the center axes of the outer ring 1 and the hub 2 coincide with each other and no axial displacement occurs), the sensors 6a ₁ , 6a ₂ , 6b ₁ , 6b ₂ , 6c ₁ , 6c ₂ are respectively opposed to the central portion in the width direction of the first characteristic changing unit 9 or the second characteristic changing unit 10. Further, in the neutral state, the detection units of a pair of sensors 6a ₁ (6b ₁ , 6c ₁ ) and 6a ₂ (6b ₂ , 6c ₂ ) constituting the same sensor set face both the characteristic change units 9 and 10. The circumferential position (angle) θ coincides with each other. Therefore, in the case of the structure of the prior invention, the initial phase difference existing between the output signals of the pair of sensors 6a ₁ (6b ₁ , 6c ₁ ) and 6a ₂ (6b ₂ , 6c ₂ ) constituting the same sensor set. (Phase difference in the neutral state) is 0 respectively. Furthermore, in the case of the structure of the prior invention, both the characteristic changing sections 9, 9, and 9, so that the initial phase difference between sensors constituting different sensor sets (existing at different circumferential positions θ) is also zero. A pitch P (length in the circumferential direction of one cycle) P of 10 characteristic changes is regulated.

In the case of the structure of the prior invention configured as described above, the outer ring 1 (the sensors 6a ₁ , 6a ₂ , 6b ₁ , 6b ₂ , 6c) is accompanied by the external force acting on the rolling bearing unit 11 via the wheels. ₁ and 6c ₂ ) and the hub 2 (detected surface of the encoder 4) are displaced from each other, the sensors 6a ₁ , 6a ₂ , 6b ₁ , 6b ₂ are correspondingly moved. , 6c ₁ and 6c ₂ change in phase. Here, the change amount (self-phase difference) of the output signal of each sensor 6a ₁ , 6a ₂ , 6b ₁ , 6b ₂ , 6c ₁ , 6c ₂ in this case is expressed as a self-phase difference ratio (self-phase difference / 1 (Period). Specifically, one of the pair of sensors 6a ₁ (6b ₁ , 6c ₁ ) and 6a ₂ (6b ₂ , 6c ₂ ) constituting each of the above sensor sets is present on the outer side in the axial direction (out side). The self-phase difference ratios relating to the sensors 6a ₁ (6b ₁ , 6c ₁ ) are represented by ε _out (θ) (θ = 0 degrees, 120 degrees, 240 degrees), respectively, The self-phase difference ratio regarding the sensor 6a ₂ (6b ₂ , 6c ₂ ) is expressed by ε _in (θ) (θ = 0 degree, 120 degree, 240 degree), respectively. Further, the encoder 4 with respect to the outer ring 1, the displacement of the x-axis direction is x, the displacement in the y-axis direction and y, the displacement in the z-axis direction and z, the slope around the x-axis and phi _x, z-axis the slope around the φ _z.

尚、これら（１）式及び（２）式の右辺中の各記号の意味は、以下の通りである。
Ｐ：上記第一、第二各特性変化部９、１０の特性変化のピッチ（１周期の円周方向長さ）
α：上記第一、第二各特性変化部９、１０に存在する特性境界の、軸方向に対する傾斜角度（先発明の構造の場合には、４５度）
Ｒ：上記第一、第二各特性変化部９、１０（被検出面）の半径
δ：上記各センサ組を構成する１対のセンサ６ａ₁ （６ｂ₁ 、６ｃ₁ ）、６ａ₂ （６ｂ₂ 、６ｃ₂ ）の検出部の中心同士の、軸方向に関する間隔（ピッチ、２δ）の１／２ In this case, between the self-phase difference ratios ε _out (θ), ε _in (θ) and the displacements x, y, z and the inclinations φ _x , φ _z , the following (1) The relationship of Formula and Formula (2) is materialized.

In addition, the meaning of each symbol in the right side of these (1) Formula and (2) Formula is as follows.
P: Characteristic change pitch of each of the first and second characteristic change portions 9 and 10 (circumferential length of one cycle)
α: Inclination angle with respect to the axial direction of the characteristic boundary existing in each of the first and second characteristic changing portions 9 and 10 (45 degrees in the case of the structure of the previous invention)
R: radius of each of the first and second characteristic changing portions 9, 10 (surface to be detected) δ: a pair of sensors 6a ₁ (6b ₁ , 6c ₁ ), 6a ₂ (6b ₂ ) constituting each sensor set , 6c ₂ ) 1/2 of the distance (pitch, 2δ) in the axial direction between the centers of the detectors.

となる。
又、第二のセンサ組を構成する各センサ６ｂ₁ 、６ｂ₂ に関する自己位相差比ε_out （１２０）、ε_in（１２０）はそれぞれ、上記（１）式及び（２）式に、θ＝１２０度、α＝４５度を代入して、

となる。
又、第三のセンサ組を構成する各センサ６ｃ₁ 、６ｃ₂ に関する自己位相差比ε_out （２４０）、ε_in（２４０）はそれぞれ、上記（１）式及び（２）式に、θ＝２４０度、α＝４５度を代入して、

となる。 Accordingly, the self-phase difference ratios ε _out (0) and ε _in (0) related to the sensors 6a ₁ and 6a ₂ constituting the first sensor set are respectively expressed by the above equations (1) and (2), θ = Substituting 0 degrees and α = 45 degrees,

It becomes.
Further, the self-phase difference ratios ε _out (120) and ε _in (120) relating to the respective sensors 6b ₁ and 6b ₂ constituting the second sensor set are respectively expressed by the following equations (1) and (2): θ = Substituting 120 degrees and α = 45 degrees,

It becomes.
Further, the self-phase difference ratios ε _out (240) and ε _in (240) relating to the sensors 6c ₁ and 6c ₂ constituting the third sensor set are respectively expressed by the following equations (1) and (2): θ = Substituting 240 degrees and α = 45 degrees,

It becomes.

となる。
又、第二のセンサ組を構成する１対のセンサ６ｂ₁ 、６ｂ₂ の出力信号同士の間に存在する位相差（相互位相差）は、相互位相差比で表すと、

となる。
又、第三のセンサ組を構成する１対のセンサ６ｃ₁ 、６ｃ₂ の出力信号同士の間に存在する位相差（相互位相差）は、相互位相差比で表すと、

となる。 Therefore, the phase difference (mutual phase difference) existing between the output signals of the pair of sensors 6a ₁ and 6a ₂ constituting the first sensor set is a mutual phase difference ratio (mutual phase difference / 1 period). To represent

It becomes.
Further, the phase difference (mutual phase difference) existing between the output signals of the pair of sensors 6b ₁ and 6b ₂ constituting the second sensor set is expressed by a mutual phase difference ratio.

It becomes.
Further, the phase difference (mutual phase difference) existing between the output signals of the pair of sensors 6c ₁ and 6c ₂ constituting the third sensor set is expressed by a mutual phase difference ratio.

It becomes.

Furthermore, here, two different phase differences (mutual phase differences) between two sensors constituting different sensor sets (existing at different circumferential positions θ) are represented by mutual phase difference ratios, respectively. The two sensor combinations adopted here may be combinations of two sensors on the out side and the in side that are different from each other, or two sensors on the same side of each other. A combination of sensors may be used. Here, in both cases, a combination of two sensors on the same side (out side) (a combination of the sensor 6a ₁ and the sensor 6b ₁ and a combination of the sensor 6a ₁ and the sensor 6c ₁ ) is employed. The mutual phase difference ratio between these two types of sensors is as follows.

となり、これを上記５つの未知数（ｘ、ｙ、ｚ、φ_x 、φ_z ）に就いての式に書き換えると、

となる。この（１５）式の右辺中、Ｐ、Ｒ、δは、前記α（＝４５度）と同様、何れも先発明の構造により決まる定数である。又、５つの相互位相差比「ε_in（０）−ε_out （０）」、「ε_in（１２０）−ε_out （１２０）」、「ε_in（２４０）−ε_out （２４０）」、「ε_out （１２０）−ε_out （０）」、「ε_out （２４０）−ε_out （０）」は、上記６個のセンサ６ａ₁ 、６ａ₂ 、６ｂ₁ 、６ｂ₂ 、６ｃ₁ 、６ｃ₂ の出力信号に基づいて求められる。従って、前述した図示しない演算器に、上記（１５）式の右辺を計算させれば、この（１５）式の左辺の５つの未知数（ｘ、ｙ、ｚ、φ_x 、φ_z ）を算出できる。 As described above, in the case of the structure of the prior invention, five relational expressions {expressions (9) to (13)} with respect to five unknowns (displacement x, y, z and inclinations φ _x , φ _z ) Therefore, the five unknowns (x, y, z, φ _x , φ _z ) can be obtained analytically. That is, when the above five relational expressions {(9) to (13)} are displayed as a matrix,

When this is rewritten into the above equation for the five unknowns (x, y, z, φ _x , φ _z ),

It becomes. In the right side of the equation (15), P, R, and δ are constants determined by the structure of the previous invention, similarly to α (= 45 degrees). Further, five mutual phase difference ratios “ε _in (0) −ε _out (0)”, “ε _in (120) −ε _out (120)”, “ε _in (240) −ε _out (240)”, “Ε _out (120) −ε _out (0)” and “ε _out (240) −ε _out (0)” are the six sensors 6a ₁ , 6a ₂ , 6b ₁ , 6b ₂ , 6c ₁ , 6c. It is obtained based on the output signal of ₂ . Therefore, if the arithmetic unit (not shown) calculates the right side of the above equation (15), the five unknowns (x, y, z, φ _x , φ _z ) on the left side of the equation (15) can be calculated. .

When the above-described calculation is performed, the distance 2δ between the centers of the detection units of the pair of sensors 6a ₁ (6b ₁ , 6c ₁ ) and 6a ₂ (6b ₂ , 6c ₂ ) constituting each sensor set is Since it is usually small, if the error can be tolerated, it is possible to calculate the 5-degree-of-freedom displacement (x, y, z, φ _x , φ _z ) with δ = 0. If the calculation is performed in this way, the speed of the arithmetic processing can be increased.

Further, the five-degree-of-freedom displacement (x, y, z, φ _x , φ _z ) and the corresponding five external force components (the load Fx in the x-axis direction, acting between the outer ring 1 and the hub 2). A predetermined relationship between the load Fy in the y-axis direction, the load Fz in the z-axis direction, the moment Mx around the x-axis, and the moment Mz around the z-axis) is determined by the rigidity of the target rolling bearing unit 11. There is. And this predetermined relationship is calculated | required not only by calculation based on the elastic contact theory etc. widely known in the field of a rolling bearing unit, but also by experiment. Therefore, if an expression or a map representing the predetermined relationship is stored in the memory of the arithmetic unit, the above-mentioned 5 is calculated based on the 5-degree-of-freedom displacement (x, y, z, φ _x , φ _z ). External force components (Fx, Fy, Fz, Mx, Mz) are obtained.

  However, when determining the radial load (Fx, Fz) acting between the outer ring 1 and the hub 2, it is necessary to pay attention to the following points. That is, the radial load (Fx, Fz) is generally calculated from the radial displacement generated in the hub 2 in the same direction as the radial load (Fx, Fz). However, the hub 2 may be displaced radially with an inclination. In this case, since the magnitude of the radial displacement of the hub 2 differs depending on the y-axis direction position, the calculation result of the radial load (Fx, Fz) differs depending on which y-axis direction position the radial displacement is read. Cause the problem. Therefore, it is important to read the radial displacement at a position in the y-axis direction where the actually acting radial load (Fx, Fz) can be accurately calculated.

Based on this point, a method for calculating the radial load Fz in the z-axis direction will be specifically described below with reference to FIGS. In an actual automobile, due to uneven wear of tires, insufficient air pressure, change in camber angle, etc., as shown schematically in FIG. 10, the position of the application point of the radial load Fz in the y-axis direction and the target rolling The y-axis direction position of the bearing center (the center between the axially outer bearing row A and the axially inner bearing row B) O of the bearing unit 11 may be inconsistent with each other. In this case, the hub 2 is radially displaced in the z-axis direction with an inclination in the yz plane as indicated by a two-dot chain line in the drawing. In addition, as schematically shown in FIG. 11, even if the y-axis direction position of the point of application of the radial load Fz and the y-axis direction position of the bearing center O coincide with each other, the bearing in the z-axis direction and stiffness k _a column a, if the z-axis direction for the different bearing row B of stiffness k _b and each other {k _a ≠ k _b (in the illustrated example k _a <k _b)} is the hub 2, Again, as shown in the drawing with its center axis indicated by a two-dot chain line, it is radially displaced in the z-axis direction with an inclination in the yz plane. 10 and 11, since the magnitude of the radial displacement in the z-axis direction of the hub 2 differs depending on the y-axis direction position, the radial displacement in the z-axis direction is read at any y-axis direction position. Depending on whether or not, the calculation result of the radial load Fz is different.

However, such a problem can be solved by using an equivalent stiffness k _eq of the rolling bearing unit 11 about the z-axis direction _{(= k a + k b)} . That is, in the situation shown in FIGS. 10 and 11, the magnitude of the radial displacement of the hub 2 in the z-axis direction is a value (Fz / k _eq ) obtained by dividing the radial load Fz by the equivalent stiffness k _eq. There exists a y-axis direction position (y-axis direction position of the rigidity center of the rolling bearing unit 11). Such a position in the y-axis direction is an optimum y-axis direction position from which the radial displacement in the z-axis direction should be read. In other words, if the radial displacement in the z-axis direction of the hub 2 is read at the optimum position in the y-axis direction, the actually acting radial load Fz can be accurately calculated.

一方、上述した様に、最適なｙ軸方向位置で読み取られるｚ軸方向のラジアル変位ｚ_eqの値は、上記ラジアル荷重Ｆｚを上記等価剛性ｋ_eq（＝ｋ_a ＋ｋ_b ）で除した値（Ｆｚ／ｋ_eq）となる。これを式で表すと、次の（１７）式の様になる。

従って、この（１７）式を満たす距離Ｈ、即ち、次の（１８）式で表される距離Ｈの位置が、上記最適なｙ軸方向位置となる。

This optimum y-axis direction position will be described in more detail with reference to FIG. First, the distance in the y-axis direction between the bearing arrays A and B is N, and the distance in the y-axis direction from the bearing array A to the point of application of the radial load Fz is M. In this case, the radial displacement z _{h in} the z-axis direction of the hub 2 at the position where the y-axis direction distance from the bearing row A is H is expressed by the following equation (16).

On the other hand, as described above, the optimum value of the radial displacement z _eq in the z-axis direction to be read by the y-axis direction position is a value obtained by dividing the radial load Fz by the equivalent stiffness _{k eq (= k a + k} b) ( Fz / k _eq ). This can be expressed by the following equation (17).

Therefore, the distance H satisfying the equation (17), that is, the position of the distance H represented by the following equation (18) is the optimum position in the y-axis direction.

又、傾きφ_x が微小な場合は、次の（２０）式で近似する事もできる。

Also, the radial displacement z _{eq in the} z-axis direction read at the optimum y-axis direction position is a part (z, φ _x ) of the above-described 5-degree-of-freedom displacement (x, y, z, φ _x , φ _z ). Is required. That is, when the distance from the center y-axis direction position of the encoder 4 to the optimum y-axis direction position is L (FIG. 8), the radial displacement z _eq can be expressed by the following equation (19).

Further, when the inclination φ _x is small, it can be approximated by the following equation (20).

In the above description, the both bearing rows A, the stiffness k _a of B, and k _b is proceeded talking assumed to be constant, since the rolling bearing unit 11 having a non-linear stiffness characteristics, other directions There is a possibility that the rigidity may change when a load is applied from (direction other than the z-axis). For example, in the case of the rolling bearing unit 11 which is the object of the structure of the previous invention, a preload is applied to both the bearing rows A and B together with the contact angle of the rear combination type. Therefore, when the axial load Fy of the hub 2 + y-direction (right direction in FIG. 12) acts, and the contact load of the bearing row A increases, the rigidity k _a of the bearing row A increases, the contact load decreases bearing column B, the stiffness k _b of the bearing row B decreases. As a result, the rigidity ratio of both the bearing arrays A and B changes, and the distance H indicating the optimum position in the y-axis direction obtained by the above equation (18) changes. In order to deal with such a problem, the distance H after the change is obtained based on the axial load Fy calculated by the computing unit, and the radial displacement in the z-axis direction is determined at the position of the distance H after the change. Just read it. Alternatively, the moment Mx of the axial load Fy is generated in association with that input from the ground surface of the tire (camber moment) causes the inclination phi _x around x-axis acts on the hub 2. Therefore, on the basis of the inclination phi _x calculated by the arithmetic unit calculates the distance H after change, it may be as reading the radial displacement of the z-axis direction at a distance H after the change.

Note that the both bearing rows A, stiffness k _a, k _b of B, not only when the axial load Fy in the rolling bearing unit 11 is applied, changes even when the radial load acts on the rolling bearing unit 11 To do. For this reason, strictly speaking, the rigidity ratio of the two bearing arrays A and B also changes depending on the radial load Fz that is the calculation purpose. However, in this case, both the bearing arrays A and B undergo substantially the same rigidity change, and the change in the distance H indicating the optimum y-axis direction position is extremely small, if any. For this reason, no significant error occurs in the calculation result of the radial load Fz even if no particular measures are taken.

  Next, another situation will be described. As schematically shown in FIG. 13, the y-axis direction position of the point of application of the radial load Fz to the rolling bearing unit 11 and the y-axis direction position of the bearing center O of the rolling bearing unit 11 coincide with each other. However, when the moment Mx around the x axis acts together with the radial load Fz, the hub 2 is also in a state with an inclination in the yz plane, as shown by the two-dot chain line in the drawing. , Radial displacement in the z-axis direction. Even in the situation shown in FIG. 13, since the magnitude of the radial displacement in the z-axis direction of the hub 2 varies depending on the position in the y-axis direction, depending on which y-axis direction position the radial displacement in the z-axis direction is read, There arises a problem that the calculation results of the radial load Fz are different.

However, such a problem is that when only the moment Mx acts on the hub 2, the hub 2 is displaced in the y-axis direction where the radial displacement in the z-axis direction becomes 0, that is, the hub generated by the moment Mx. The node position with the inclination φ _x of 2 can be eliminated by setting the radial displacement reading position in the z-axis direction. Since the rolling bearing unit 11 has non-linear stiffness characteristics, the node position may vary somewhat depending on the magnitude of the moment Mx (inclination φ _x ). In such a case, based on the moment Mx (inclination φ _x ) calculated by the calculator, the node position after the change is obtained, and the radial displacement in the z-axis direction is read at the node position after the change. It ’s fine.

Note that the moment Mx about the x-axis may be an error factor when calculating the radial load Fx in the x-axis direction (reading the radial displacement in the x-axis direction). That is, since the moment Mx is a large moment, the inclination φ _{x of the} hub 2 caused by the moment Mx becomes large. Here, suppose that each of the sensors 6a ₁ , 6a ₂ , 6b ₁ , 6b ₂ , 6c ₁ , 6c ₂ is from the predetermined circumferential position (positions θ = 0 degrees, 120 degrees, 240 degrees). It is assumed that it is installed at a circumferential position that is slightly shifted (shifted by φ _y as an angle). In this case, the coordinate axes of the sensors 6a ₁ , 6a ₂ , 6b ₁ , 6b ₂ , 6c ₁ , 6c ₂ are inclined by the angle φ _y around the y axis (in the xz plane). the moment Mx by results about the x-axis (in the y-z plane) inclination phi _x is detected as the gradient with a (x-y plane) component about the z axis. The component in the xy plane is only the amount of sin φ _y of the angle φ _y that is an attachment misalignment, but since the inclination φ _x due to the original moment Mx is large as described above, An error may occur in the reading of the radial displacement. In order to prevent such an error from occurring, the radial displacement in the x-axis direction may be read at the node position of the inclination φ _x around the x-axis (in the yz plane).

To summarize the above story, in order to accurately calculate the radial load Fz in the situation shown in FIGS. 10 and 11, the radial displacement in the z-axis direction may be read at the rigidity center of the rolling bearing unit 11, Further, in order to accurately calculate the radial load Fz in the situation shown in FIG. 13, it is only necessary to read the radial displacement in the z-axis direction at the node position of the inclination φ _x of the hub 2 caused by the moment Mx. It will be a thing. Here, if the rolling bearing unit 11 is a linear spring, the y-axis direction positions of the rigid center and the node position coincide with each other. However, since the rolling bearing unit 11 has nonlinear rigidity characteristics, the y-axis direction positions of the center of rigidity and the node position may not coincide with each other. The reason why such a phenomenon occurs is that the distribution of contact load acting on the bearing arrays A and B differs between the situation shown in FIGS. 10 and 11 and the situation shown in FIG.

  However, even when the y-axis direction positions of the rigid center and the node position do not coincide with each other as described above, there is no great gap between the y-axis direction positions. For this reason, the y-axis direction position corresponding to one of the situation shown in FIGS. 10 and 11 and the situation shown in FIG. 13 is used as the radial displacement reading position in the z-axis direction. Even when the other situation occurs, there is no inconvenience that the calculation error of the radial load Fz becomes so large that it becomes a practical problem. That is, even when the other situation occurs, the calculation accuracy of the radial load Fz can be reduced to a practically satisfactory level. Also, an arbitrary y-axis position (between the central position or one of the y-axis positions depending on the degree of problem) existing between the y-axis positions of the rigid center and the node position. (Position) can be a position at which radial displacement in the z-axis direction is read. In this way, the calculation error of the radial load Fz can be suppressed in a well-balanced manner in each of the situations described above.

  In the above description, the calculation method of the radial load Fz in the z-axis direction is mainly taken up, but the same applies to the calculation method of the radial load Fx in the x-axis direction. For example, when the rigidity ratios of the two bearing arrays A and B are the same in the x-axis direction and the z-axis direction, the optimum y-axis direction position for reading the radial displacement is the same position in both axial directions. If not, they will be in different positions.

  In addition, since the rolling bearing unit 11 which is the object of this example has nonlinear rigidity characteristics, the load conversion coefficient when calculating the radial load in the same direction from the radial displacement read as described above is also nonlinear. Of course. Therefore, it is effective to convert the radial displacement into the radial load using a map.

  Further, as the optimum y-axis direction position for reading the radial displacement and the load conversion coefficient, those calculated in advance by design may be used, or those actually measured at the time of shipment at the factory may be used. However, in any case, when the preload applied to the bearing rows A and B of the rolling bearing unit 11 changes, the optimal y-axis direction position and the load conversion coefficient change accordingly. Therefore, in order to deal with such a problem, for example, the optimum y is measured while measuring the preload during driving of the vehicle by the method disclosed in Japanese Patent Application No. 2006-065675 and various conventionally known methods. It is preferable to correct the axial position and the load conversion coefficient.

As described above, according to the structure of the previous invention, a 5-degree-of-freedom displacement (x, y, z, φ _x , φ _z ) and five external force components (Fx, Fy, Fz, Mx, Mz) are converted into one encoder. 4 is used. For this reason, the cost of the state quantity measuring apparatus 12 used when calculating | requiring each of these state quantities (displacement, external force) can fully be suppressed. At the same time, the state quantity measuring device 12 can be sufficiently downsized. Therefore, even when the target rolling bearing unit 11 does not have a wide mounting space, the state quantity measuring device 12 can be easily assembled to the rolling bearing unit 11. In the case of the structure of the above-described prior invention, since radial displacement (x, z) and radial load (Fx, Fz) in two directions (x direction and z axis direction) orthogonal to each other are obtained, these components are obtained. Can be used to easily calculate radial displacements and radial loads in other directions in the xz plane. Similarly, in this example, since the inclination (φ _x , φ _z ) and moment (Mx, Mz) around two axes (x axis, z axis) orthogonal to each other can be obtained, these components are used. Thus, tilts and moments around other axes existing in the xz plane can be easily calculated.

By the way, in the case of the structure of the prior invention described above, the _first and _second detection units of the six sensors 6a ₁ , 6a ₂ , 6b ₁ , 6b ₂ , 6c ₁ , 6c ₂ are arranged side by side in the axial direction. A configuration is adopted in which each of the characteristic change sections 9 and 10 is opposed to each other by three. However, the installation space of each of the sensors 6a ₁ , 6a ₂ , 6b ₁ , 6b ₂ , 6c ₁ , 6c ₂ depends on the structure of the target rolling bearing unit 11 and the structure of the assembly part on the vehicle. In many cases, it becomes a narrow space. For this reason, depending on the case, the detection of the six sensors 6a ₁ , 6a ₂ , 6b ₁ , 6b ₂ , 6c ₁ , 6c ₂ as described above due to the restriction of the size of the installation space (particularly the axial dimension). It may be difficult to make three parts face each of the first and second characteristic change parts 9 and 10.

JP 2006-1113017 A

In view of the circumstances as described above, the state quantity measuring device for a rotating machine according to the present invention has a structure other than three detection units of six sensors opposed to the first and second characteristic change units. The present invention was invented to realize a structure capable of measuring the degree of freedom displacement (x, y, z, φ _x , φ _z ).

The rotating machine state quantity measuring apparatus of the present invention includes a rotating machine and a state quantity measuring apparatus.
Among these, the rotating machine includes a stationary member that does not rotate even when in use, and a rotating member that is rotatably supported by the stationary member.
In addition, the state quantity measuring device includes an encoder supported and fixed to a part of the rotating member directly or via another member, a sensor device supported and fixed to a part that does not rotate during use, and an arithmetic unit. Prepare.
Among these, the encoder includes a detected surface on a circumferential surface concentric with the rotating member, and includes first and second characteristic changing portions at two positions which are out of the detected surface in the axial direction. The characteristics of these two characteristic changing parts change alternately and at the same pitch in the circumferential direction, and the phase of the characteristic change of at least one of the first and second characteristic changing parts is With respect to the axial direction, it gradually changes in a state different from the other characteristic changing portion.
In addition, the sensor device includes four or more sensors that change the output signal in response to a change in characteristics of a portion facing the detection unit. And assuming that the total number of each of these sensors is 6, under the condition not adopting a configuration in which three detection units of each of these sensors are opposed to both the first and second characteristic change units (described above). (Except for the structure in which six sensors are opposed to the three characteristic change parts three at a time as in the previous invention), among the detection parts of the four or more sensors, the detection part of one sensor is In one characteristic change part, the detection part of another one sensor is the second characteristic change part, and the detection part of each remaining sensor is the other one of the first characteristic change part or the second characteristic change part. Each of the sensors is opposed to a portion spaced in the circumferential direction with respect to a portion facing the detection unit.
Further, when the y-axis of the three-dimensional orthogonal coordinate system composed of the x-axis, y-axis, and z-axis orthogonal to each other is made coincident with the central axis of the stationary member, each of the computing units is more than four Phase difference {or phase difference ratio (= phase difference / 1 period)} existing between the output signals of two sensors selected from among the two sensors, and two different from each other Based on the five phase differences (or phase difference ratios) relating to the sensor combination, the x-axis direction displacement x, the y-axis direction displacement y, and the z-axis direction displacement z of the encoder relative to the stationary member , Have a function of calculating an inclination φ _x around the x axis and an inclination φ _z around the z axis, respectively.

When carrying out the invention described in claim 1 described above, for example, as described in claim 2, the total number of sensors constituting the sensor device is six.
In carrying out the invention described in claims 1 and 2, preferably, as described in claim 3, among the first and second characteristic change units, the detection units of a plurality of sensors. With respect to at least one of the characteristic changing portions that are opposed to each other, the opposing positions of the detection units of the plurality of sensors with respect to the characteristic changing portion are defined as circumferentially equidistant positions.

In carrying out the invention described in claims 1 to 3, preferably, as described in claim 4, each displacement x, y, z and each inclination φ _x , φ _z are calculated. The five phase differences (or phase difference ratios) used in the above are expressed in a neutral state in which the displacements x, y, z and the inclinations φ _x , φ _z are 0, each having a magnitude of a certain value or more { Preferably, the phase difference is 180 degrees (or a phase difference ratio of 0.5) that are opposite to each other. For this purpose, the five phase differences (or phase difference ratios) are more than a certain value in the neutral state, taking into consideration the number of characteristic changes per round of the first and second characteristic change portions. The opposing position of the detection part of each sensor with respect to both the first and second characteristic change parts is regulated so that Or, due to various circumstances, the opposing position of the detection unit of each sensor with respect to both the first and second characteristic change units is restricted so that the five phase differences (or phase difference ratios) become zero in the neutral state. If this is not possible, the polarities (+/−) of the two sensors for obtaining the phase difference are reversed, or the polarities (+/−) of the two sensors are reversed in the circuit that receives these two sensor signals. It is also possible to adopt measures to

  When the inventions described in claims 1 to 4 are implemented, as described in claim 5, the phase of the characteristic change of one of the first and second characteristic change parts is the same. It is also possible to adopt a configuration in which only the change in the axial direction is made and the phase of the characteristic change of the other characteristic change unit is not changed in the axial direction.

Further, when carrying out the inventions described in the first to fifth aspects, preferably, as described in the sixth aspect, the calculator calculates the displacement and inclination of the encoder relative to the stationary member calculated by itself (each displacement). Based on x, y, z and at least a part of each inclination φ _x , φ _z , external force acting between the stationary member and the rotating member (for example, load Fx in the x-axis direction, A function of calculating a load Fy, a load Fz in the z-axis direction, a moment Mx around the x-axis, and a moment Mz around the z-axis) is provided.
Further, when the invention described in claim 6 is carried out, for example, as described in claim 7, the stationary calculator calculates the stationary state based on the displacement and inclination of the encoder relative to the stationary member calculated by itself. The radial displacement (displacement in the xz plane) of the rotating member at a predetermined position in the axial direction (y-axis direction) of the member is calculated, and the stationary member and the rotation are calculated based on the radial displacement. A function of calculating a radial load acting in the same direction as the radial displacement acting between the members is provided.

Further, when the invention described in claim 7 is carried out, as described in claim 8, for example, the axial position of the center of rigidity of the rotary machine in the same direction as the radial displacement to be calculated is stationary. A predetermined position in the axial direction of the member is used.
Alternatively, as described in claim 9, when only a moment acts between the stationary member and the rotating member, the axial position where the radial displacement of the rotating member becomes zero is defined as the predetermined axial direction of the stationary member. The position of
Alternatively, as described in claim 10, when only a moment acts between the axial position of the center of rigidity of the rotating machine in the same direction as the radial displacement to be calculated and the stationary member and the rotating member, An arbitrary (preferably central) axial position existing between an axial position where the radial displacement of the rotating member is 0 is defined as a predetermined position in the axial direction of the stationary member.

  Further, when carrying out the invention described in claims 6 to 10 above, preferably, as described in claim 11, the calculator has a displacement or inclination of the encoder relative to the stationary member calculated by itself, or A predetermined position in the axial direction of the stationary member based on a component in a direction different from the radial displacement to be calculated among external forces acting between the stationary member and the rotating member calculated based on the displacement or inclination. To correct.

When carrying out the invention described in the above first to eleventh aspects, for example, as described in the twelfth aspect, the rotary machine is a rolling bearing unit. This rolling bearing unit includes a stationary bearing ring that is a stationary member, a rotating bearing ring that is a rotating member, and stationary bearings that exist on circumferential surfaces facing each other of the stationary bearing ring and the rotating bearing ring. A plurality of rolling elements provided between the rotating side track and the rotating side track.
In carrying out the invention described in claim 12, preferably, as described in claim 13, the rolling bearing unit is a hub unit for supporting a wheel of an automobile. In use, the stationary bearing ring is supported by the automobile suspension, and the wheel is coupled and fixed to the hub which is the rotating bearing ring.

According to the state quantity measuring apparatus of the rotating machine of the present invention configured as described above, the five-degree-of-freedom displacement (x, y, z, φ _x , φ _z ) It is determined using one encoder. The reason for this is as follows. That is, as in the case of the structure of the prior invention shown in FIGS. 6 to 13 described above, each is a phase difference (or phase difference ratio) between the output signals of the two sensors and is different from each other. When calculating the five-degree-of-freedom displacement (x, y, z, φ _x , φ _z ) based on the five phase differences (or phase difference ratios) for two sensor combinations, the first It is not necessary to make the same number of detection parts of the sensor face the second both characteristic change parts. The condition is that one or more sensor detection units are opposed to both the first and second characteristic change units, and at least five combinations of two sensors can be selected from each sensor. {5 phase differences (or phase difference ratios) can be obtained}. In the case of the present invention, since this condition is satisfied, the five-degree-of-freedom displacement (x, y, z, φ _x , φ _z ) is converted into one encoder as in the case of the structure of the previous invention. Sought using.

  Further, as described above, in the case of the present invention, it is not necessary to make the same number of sensor detection portions face the first and second characteristic change portions. For this reason, when the installation space of the sensor is small and it is difficult to make the same number of sensor detection parts face the first and second characteristic change parts, the first and second characteristic change parts The installation of the sensors in the installation space can be facilitated by making the number of detection parts of the sensors opposed to each other different.

Further, if the structure described in claim 5 is adopted, calculation for calculating the five-degree-of-freedom displacement (x, y, z, φ _x , φ _z ) from five phase differences (or phase difference ratios). The amount can be reduced {specifically, a large number of 0 can be included in the matrix element of 5 rows and 5 columns in the same formula as the formula (14) related to the present invention}. For this reason, although the measurement accuracy is somewhat deteriorated, the five-degree-of-freedom displacement (x, y, z, φ _x , φ _z ) can be calculated in a state closer to real time. Further, the rotation speed of the rotating member can be obtained with high accuracy based on a detection signal of a sensor in which the detection unit is opposed to the characteristic change unit that does not change the phase in the axial direction.
Further, if the structure described in claim 6 is adopted, external forces acting between the stationary member and the rotating member (for example, load Fx in the x-axis direction, load Fy in the y-axis direction, load Fz in the z-axis direction, The moment Mx around the x-axis and the moment Mz around the z-axis) are determined using one encoder.
Moreover, if the structure as described in Claims 7-11 is employ | adopted, the radial load which acts between a stationary member and a rotation member will be calculated | required with sufficient precision.

1-2 show an example of an embodiment of the present invention corresponding to claims 1 to 4 and 6 to 13. The feature of this example is that among the _six sensors 6s _{1 to} 6s 6 constituting the sensor device, the number of sensors opposed to the first characteristic changing unit 9 and the sensor opposed to the second characteristic changing unit 10 are as follows. Is different from each other. Since the structure and operation of other parts are the same as those of the structure of the prior invention shown in FIGS. 6 to 13 described above, the same parts are denoted by the same reference numerals, and overlapping illustrations and descriptions are omitted or simplified. In the following, the characteristic part of this example and the part different from the structure of the previous invention will be mainly described.

This example, by the size constraints of the installation space of the six sensor 6s ₁ ~6s _6, the detection portion of the six sensor 6s ₁ ~6s _6, the first, second double characteristic change portions 9 and 10 It is intended for structures that are difficult to face each other. Therefore, in the case of this example, the six sensor 6s ₁ ~6s ₆ in the installation space, so as to the manner effectively placed in terms of the state quantity measured, the six sensor 6s ₁ ˜6s ₆ , the detection units of the _two sensors 6 s ₁ and 6 s ₂ are used as the first characteristic change unit 9, and the detection units of the remaining four sensors 6 s _{3 to 6 s 6} are used as the second characteristic change unit 10. , Each has a facing structure. Specifically, the detection units of the _two sensors 6s ₁ and 6s ₂ are opposed to the position of θ = 60 degrees and the position of θ = 300 degrees of the first characteristic change unit 9, respectively. Further, the detection units of the four sensors 6s _{3 to} 6s ₆ are respectively set to a position of θ = 0 degrees, a position of θ = 90 degrees, and a position of θ = 180 degrees of the second characteristic changing unit 10; Opposite to the position of θ = 270 degrees. If the sensor arrangement structure of this example is adopted, the six sensors 6s _{1 to} 6s ₆ cannot be effectively arranged in any installation space. That is, when carrying out the present invention, the number of detection parts of the sensor facing each of the first and second characteristic change parts 9, 10 and the circumferential position θ of each detection part are prepared. and installation space above six sensor 6s ₁ ~6s ₆ as can be effectively disposed of, appropriately determined. In any case, in the case of this example, in the neutral state, any one of these six sensors 6s _{1 to} 6s ₆ is selected between the output signals of any one of the two sensors. The characteristic change pitch P of the first and second characteristic change sections 9 and 10 is such that a phase difference ratio of 0.5 (phase difference of 180 degrees) is generated even in the case of the pair (see FIG. 7). And the polarities (+/−) of the sensors 6s _{1 to} 6s ₆ are made different from each other as necessary.

Also in this example, as in the case of the structure of the previous invention described above, the 5-degree-of-freedom displacement of the encoder 4 with respect to the outer ring 1 (displacement x in the x-axis direction, displacement y in the y-axis direction, displacement z in the z-axis direction) inclination phi _x around the x axis, in order to calculate the inclination phi _z) about the z axis, each of the output signals between the two sensors selected from the above-mentioned six sensors 6s ₁ ~6s ₆ A combination of two sensors each having a phase difference ratio existing between them and different from each other (in the case of this example, there are ₆ C ₂ = 15 combinations in total. For example, a combination of the sensors s ₁ and s ₂ , a combination of the sensors s ₃ and s ₅ , a combination of the sensors s ₄ and s _6, and the sensors s ₁ and s ₃ with a combination of five retardation ratio about the total combination of five different) epsilon ₁ to use the ε _5.

尚、この（２１）式の右辺の５行５列の行列要素には、上記５通りの２個ずつのセンサの組み合わせの選択の仕方によって、それぞれ異なった数値が入る。
更に、上記（２１）式を、上記５自由度変位（ｘ、ｙ、ｚ、φ_x 、φ_z ）に就いての式に書き換えた、次の（２２）式を得る。

そして、この（２２）式の関係を、演算器のメモリ中に記憶させておく。そして、運転中に実測した、上記５つの位相差比ε₁ 〜ε₅ に基づいて、上記演算器に上記（２２）式の右辺を計算させる事により、上記５自由度変位（ｘ、ｙ、ｚ、φ_x 、φ_z ）を算出する。 For this reason, specifically, with respect to the above-mentioned five combinations of two sensors, the equations corresponding to the equations (3) to (13) are obtained based on the equations (1) and (2). Further, the following expression (21) corresponding to the expression (14) is obtained.

The matrix element of 5 rows and 5 columns on the right side of the equation (21) has different numerical values depending on how to select the five combinations of the two sensors.
Further, the following expression (22) is obtained by rewriting the above expression (21) into the expression for the five-degree-of-freedom displacement (x, y, z, φ _x , φ _z ).

Then, the relationship of the equation (22) is stored in the memory of the arithmetic unit. Then, based on the _five phase difference ratios ε _{1 to} ε 5 actually measured during operation, the computing unit calculates the right side of the equation (22), whereby the five-degree-of-freedom displacement (x, y, z, φ _x , φ _z ) are calculated.

In this example, in the neutral state, a phase difference ratio of 0.5 (between the output signals of any two of the _six sensors 6s _{1 to} 6s 6) A phase difference of 180 degrees). For this reason, when the phase difference ratio between the two sensors related to each of the combinations changes with the displacement of the encoder 4 with respect to the outer ring 1, a pulse of an output signal is generated between the two sensors. It is possible to prevent the edge timing from being reversed (so-called overtaking). Therefore, it is possible to normally detect the phase difference ratio between the two sensors with respect to each of the combinations without monitoring the presence or absence of the reverse rotation.

Also in this example, as in the case of the structure of the above-described prior invention, the outer ring 1 and the outer ring 1 are based on the five-degree-of-freedom displacement (x, y, z, φ _x , φ _z ) calculated as described above. Five external force components acting on the hub 2 (the load Fx in the x-axis direction, the load Fy in the y-axis direction, the load Fz in the z-axis direction, the moment Mx around the x-axis, and the moment Mz around the z-axis) can be obtained. . In particular, in the case of this example as well, the radial load acting between the outer ring 1 and the hub 2 can be obtained with high accuracy as described with reference to FIGS. (Claims 7 to 11).

As described above, in the case of the state quantity measuring device of the rotating machine of this example, three detection units of the _six sensors 6s _{1 to} 6s 6 are provided in each of the first and second characteristic change units 9 and 10. While adopting a structure other than the facing, the 5-degree-of-freedom displacement (x, y, z, φ _x , φ _z ) of the encoder 4 with respect to the outer ring 1 and five external force components acting between the outer ring 1 and the hub 2 (Fx, Fy, Fz, Mx, Mz) is obtained using one encoder 4.

  In addition, this invention can employ | adopt not only the structure of embodiment mentioned above but the various structures which satisfy | fill the requirements described in the claim. For example, the total number of sensors constituting the sensor device may be other than six as long as it is four or more. This is because if the total number of sensors is four or more, five or more combinations of two sensors can be obtained (six in the case of four). In both the first and second characteristic changing portions, the opposing positions of the detection portions of the sensors may be equal intervals or unequal intervals in the circumferential direction. In addition, the above formulas (3) to (8) were derived based only on the geometric positional relationship, but in reality, a phase difference ratio as theoretically occurred due to the influence of Gap dependence, nonlinearity, directivity, etc. Sometimes not. In such a case, as a countermeasure, for example, based on an actual measurement value, the formula related to the present invention corresponding to the above formulas (3) to (8) is corrected or used, or shipped from a factory. Occasionally, an expression related to the present invention corresponding to the expressions (3) to (8) is actually measured, and this actually measured value is reflected and used in software installed in a computing unit.

  In addition, as described in the structure of the previous invention, the displacement of the rotating side raceway with respect to the stationary side raceway with a predetermined degree of freedom (for example, x) and the same direction acting between these raceways. The relationship with the external force (for example, Fx) is slightly different depending on the external force (for example, Fy, Fz, Mx, Mz) in other directions acting between the two race rings at that time. However, the influence of such external forces in other directions is examined in advance by experiments or simulations of the mutual relationship between the displacement in the predetermined direction, the external force in the same direction, and the external force in the other direction. I can leave. Then, by calculating with map convergence, simultaneous equations, or the like by software installed in the computing unit, the external force in the other direction can be accurately obtained without the influence of the external force in the other direction.

The schematic diagram which shows one example of embodiment of this invention. The figure which shows the circumferential direction position of a sensor. Sectional drawing which shows one example of the conventional structure of the state quantity measuring apparatus of a rolling bearing unit. The figure which looked at a part of the to-be-detected surface of an encoder from the radial direction outer side. The diagram for demonstrating the state from which the output signal of a pair of sensor changes based on an axial load. Sectional drawing which shows one example of the structure of previous invention regarding the state quantity measuring apparatus of a rolling bearing unit. The figure which looked at a part of the to-be-detected surface of an encoder from the radial direction outer side. The schematic diagram which shows an example of the structure of a prior invention. The figure which shows the circumferential direction position of a sensor. The schematic diagram which shows the condition where the radial load Fz is acting on the position of the y-axis direction which shifted | deviated from the bearing center O. FIG. The schematic diagram which shows the situation where the radial load Fz is acting on the y-axis direction position of the bearing center O, but the rigidity of a pair of bearing rows A and B is mutually different. The schematic diagram for demonstrating the optimal y-axis direction position which reads the radial displacement of az-axis direction. The schematic diagram which shows the condition where the moment Mx is acting with the radial load Fz.

Explanation of symbols

1 the outer ring 2 hub 3 rolling element 4 encoder 5 cover _{6a 1, 6a 2, 6b 1} , 6b 2, 6c 1, 6c 2, 6s 1 ~6s 6 sensor 7 through holes 8 column portion 9 first characteristic change portion 10 second Characteristic change part 11 Rolling bearing unit 12 State quantity measuring device

Claims (13)

A rotating machine and a state quantity measuring device;
Among these, the rotating machine includes a stationary member that does not rotate even when in use, and a rotating member that is rotatably supported with respect to the stationary member.
The state quantity measuring apparatus includes an encoder supported and fixed to a part of the rotating member directly or via another member, a sensor device supported and fixed to a part that does not rotate even when used, and a computing unit. Is,
The encoder includes a detected surface on a peripheral surface concentric with the rotating member, and includes first and second characteristic changing portions at two positions on the detected surface that are separated from each other in the axial direction. Thus, the characteristics of these two characteristic changing portions change alternately and at the same pitch in the circumferential direction, and the phase of the characteristic change of at least one of the first and second characteristic changing portions is Regarding the axial direction, it is gradually changing in a state different from the other characteristic change part,
It is assumed that the sensor device includes four or more sensors that change the output signal in response to the characteristic change of the part facing the detection unit, and the total number of these sensors is six. In such a case, one sensor among the four or more detection units is not used under the condition that three detection units of each sensor are opposed to the first and second characteristic change units. The detection unit is the first characteristic change unit, the detection unit of another sensor is the second characteristic change unit, and the detection units of the remaining sensors are the first characteristic change unit or the second characteristic, respectively. Each of the changing portions is opposed to a portion spaced in the circumferential direction with respect to a portion facing the detection portion of another sensor,
When the y-axis of the three-dimensional orthogonal coordinate system composed of the x-axis, y-axis, and z-axis orthogonal to each other coincides with the central axis of the stationary member, each of the computing units includes the four or more sensors. The phase difference existing between the output signals of two sensors selected from among the five sensors and the five phase differences relating to two different combinations of sensors, A function of calculating the displacement x in the x-axis direction, the displacement y in the y-axis direction, the displacement z in the z-axis direction, the inclination φ _x around the x axis, and the inclination φ _z around the z axis of the encoder. Having
A state machine for rotating machines.   The state quantity measuring device for a rotary machine according to claim 1, wherein the total number of sensors constituting the sensor device is six.   With respect to at least one of the first and second characteristic change parts, the opposite positions of the detection parts of the plurality of sensors with respect to the characteristic change part are set to the circumference. The state quantity measuring device for a rotary machine according to any one of claims 1 and 2, wherein the state amount measuring device is at equal intervals in the direction. The displacement x, y, z and the inclination phi _x, 5 single retardation utilized to calculate the phi _z found respective displacements x, y, z and the inclination phi _x, phi _z is 0 The state quantity measuring device for a rotary machine according to any one of claims 1 to 3, wherein each of the neutral state has a size equal to or greater than a certain value.   Of the first and second characteristic change parts, only the characteristic change phase of one characteristic change part changes in the axial direction, and the characteristic change phase of the other characteristic change part does not change in the axial direction. The state quantity measuring device for a rotary machine according to any one of claims 1 to 4.   The computing unit has a function of calculating an external force acting between the stationary member and the rotating member based on the displacement and inclination of the encoder with respect to the stationary member calculated by itself. The state quantity measuring device of the rotary machine described in the item.   The computing unit calculates the radial displacement of the rotating member at a predetermined position with respect to the axial direction of the stationary member based on the displacement and inclination of the encoder with respect to the stationary member calculated by itself, and based on the radial displacement, The state quantity measuring apparatus for a rotating machine according to claim 6, having a function of calculating a radial load acting between the stationary member and the rotating member in the same direction as the radial displacement.   The rotating machine state quantity measuring device according to claim 7, wherein the axial position of the center of rigidity of the rotating machine in the same direction as the radial displacement to be calculated is a predetermined position in the axial direction of the stationary member.   The rotation according to claim 7, wherein when only a moment acts between the stationary member and the rotating member, an axial position where the radial displacement of the rotating member becomes zero is set as a predetermined position in the axial direction of the stationary member. Machine state quantity measuring device.   The axial position of the center of rigidity of the rotating machine in the same direction as the radial displacement to be calculated, and the axial position where the radial displacement of this rotating member becomes zero when only a moment acts between the stationary member and the rotating member The apparatus for measuring a state quantity of a rotary machine according to claim 7, wherein an arbitrary axial position existing between and is a predetermined position in the axial direction of the stationary member.   Of the displacement or inclination of the encoder relative to the stationary member calculated by itself, or the external force acting between the stationary member and the rotating member calculated based on this displacement or inclination, the radial displacement to be calculated The apparatus for measuring a state quantity of a rotating machine according to any one of claims 6 to 10, wherein a predetermined position in the axial direction of the stationary member is corrected based on a component in a different direction.   The rotating machine is a rolling bearing unit, and the rolling bearing unit is a stationary member that is a stationary member, a rotating member that is a rotating member, and a stationary member that is opposed to the rotating member and the rotating member. The rotating machine according to any one of claims 1 to 11, comprising a plurality of rolling elements provided between a stationary-side track and a rotating-side track existing on a peripheral surface. State quantity measuring device.   The rolling bearing unit is a hub unit for supporting a wheel of an automobile, the stationary side bearing ring is supported by a suspension of the automobile in use, and the wheel is coupled and fixed to a hub that is a rotating side bearing ring. State machine for measuring the state quantity of a rotating machine.

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