JP4882403B2 - Encoder and state quantity measuring device - Google Patents

Description

  An encoder and a state quantity measuring device according to the present invention are incorporated in a wheel bearing rolling bearing unit that rotatably supports a vehicle (automobile) wheel with respect to a suspension device, for example, This is used to measure the relative displacement amount of the motor and the state quantities such as the load acting between the two race rings.

  For example, a rolling bearing unit is used to rotatably support a vehicle wheel with respect to a suspension device. Also, in order to ensure vehicle running stability, vehicle running state stabilization devices such as an anti-lock brake system (ABS), traction control system (TCS), and electronic stability control device (ESC) are widely used. Yes. In order to control such various vehicle running stabilizers, signals such as the rotational speed of the wheels and the acceleration in each direction applied to the vehicle body are required. In order to perform more advanced control, it may be preferable to know the magnitude of a load (at least one of a radial load, an axial load, and a moment) applied to the rolling bearing unit via the wheel.

  In order to cope with such a problem, it is conceivable to incorporate a load measuring device for measuring a load applied to the wheel in a rolling bearing unit for supporting the wheel with respect to the suspension device. Conventionally, for example, those described in Patent Documents 1 to 4 are known as wheel bearing rolling bearing units with load measuring devices that can be used in such cases. However, in the case of the wheel bearing rolling bearing unit with a load measuring device described in these Patent Documents 1 to 4, the cost is increased, or it is difficult to ensure sufficient durability and load measurement accuracy. There is an inconvenience.

  As a structure that can eliminate such inconvenience, Japanese Patent Application No. 2005-147642 describes the magnitude of the load applied to the rolling bearing unit based on the phase difference between the output signals of a pair of sensors arranged in the direction of the load. An invention to measure is disclosed. 8 to 11 show a first example of the prior invention disclosed in Japanese Patent Application No. 2005-147642. As shown in FIG. 8, the structure of the first example of the prior invention is a rotating side track that supports and fixes a wheel radially inward of the outer ring 1, which is a stationary side ring that does not rotate while being supported by a suspension device. A hub 2 that is a ring is rotatably supported via a plurality of rolling elements 3 and 3. The rolling elements 3 and 3 are provided with a contact pressure and a preload that is not lost regardless of the direction and magnitude of the load applied during use. Then, the rolling elements arranged in a double row at the intermediate portion in the axial direction of the outer ring 1 which is a stationary side raceway ring are fitted and fixed to the intermediate portion of the hub 2 with a permanent magnet. A pair of sensors 5 and 5 are provided between the portions 3 and 3 in a state in which the respective detection portions are closely opposed to the outer peripheral surface of the encoder 4a, which is the detection surface.

  As shown in FIGS. 9 to 11, on the outer peripheral surface of the encoder 4a, there are a portion magnetized in the N pole (first characteristic portion) and a portion magnetized in the S pole (second characteristic portion). They are alternately arranged at equal intervals in the direction. The boundary lines between the part magnetized in the N pole and the part magnetized in the S pole are linear at both axial side parts with the axial middle part of the encoder 4a as a boundary. Then, the inclination angle (absolute value) of the boundary line with respect to the axial direction of the encoder 4a is made equal to each other at both sides in the axial direction, and the inclination direction of the boundary line with respect to the axial direction of the encoder 4a is set to the axial direction. The two sides are reversed. That is, the boundary line has a "<" shape with the axially intermediate portion protruding most on one side in the circumferential direction. Therefore, the portion magnetized in the N pole and the portion magnetized in the S pole are each formed in a “<” shape with the axially intermediate portion protruding most on one side in the circumferential direction.

  Each of the sensors 5 and 5 incorporates a magnetic detection element such as a Hall IC, a Hall element, MR, or GMR in the detection unit. The positions at which the detection parts of both the sensors 5 and 5 face the outer peripheral surface of the encoder 4a are the same with respect to the circumferential direction of the encoder 4a. In other words, the detection parts of the sensors 5 and 5 are arranged on the same virtual plane including the central axis of the outer ring 1. Further, in a state where an axial load is not applied between the outer ring 1 and the hub 2, a circumferential direction is provided at the axial center portion between the portion magnetized at the N pole and the portion magnetized at the S pole. The positions where the members 4a, 5 and 5 are installed so that the most protruding part (the part where the inclination direction of the boundary line changes) exists at the center position between the detection parts of the sensors 5 and 5 above. Is regulated.

  In the case of the first example of the prior invention configured as described above, when an axial load is applied between the outer ring 1 and the hub 2, the phase in which the output signals of the sensors 5, 5 change is shifted. That is, in a state where an axial load is not applied between the outer ring 1 and the hub 2, the detection parts of the sensors 5 and 5 are on the solid lines A and B in FIG. It faces a portion that is shifted by the same amount in the axial direction from the most protruding portion. Accordingly, the phases of the output signals of the sensors 5 and 5 coincide as shown in FIG. On the other hand, when a downward axial load acts on the hub 2 to which the encoder 4a is fixed in FIG. 11A (the outer ring 1 and the hub 2 are relatively displaced in the axial direction), The detection parts of the sensors 5 and 5 are opposed to the broken lines B and B in FIG. 11A, that is, the parts different from each other in the axial direction from the most protruding part. In this state, the phases of the output signals of the sensors 5 and 5 are shifted as shown in FIG. Further, when an upward axial load is applied to the hub 2 to which the encoder 4a is fixed as shown in FIG. 11A, the detecting portions of both the sensors 5 and 5 are connected to the chain line hub of FIG. , C, that is, the deviation in the axial direction from the most projecting portion opposes different portions in the opposite direction. In this state, the phases of the output signals of the sensors 5 and 5 are shifted as shown in FIG.

  Thus, in the case of the first example of the present invention, the phase of the output signals of the sensors 5 and 5 is an axial load applied between the outer ring 1 and the hub 2 (the outer ring 1 and the hub 2 The direction of the relative displacement in the axial direction is shifted in accordance with the direction. Further, the degree of the phase shift of the output signals of the sensors 5 and 5 due to this axial load (relative displacement) increases as the axial load (relative displacement) increases. Therefore, in the case of the first example of the above-described prior invention, the outer ring 1 and the outer ring 1 are determined based on the presence / absence of the phase shift of the output signals of the sensors 5 and 5 and, if there is a shift, the direction and magnitude. The direction and magnitude of the axial relative displacement with the hub 2 and the direction and magnitude of the axial load acting between the outer ring 1 and the hub 2 are determined.

  Next, FIG. 12 shows a second example of the prior invention disclosed in Japanese Patent Application No. 2005-238175. In the case of the second example of the prior invention, the inner end of the hub 2 which is a rotating side race (“inside” with respect to the axial direction refers to the center in the width direction of the vehicle in the assembled state in the automobile, FIG. , 8, 12, and 13) are supported and fixed concentrically with the hub 2 via a support ring 6 having a cross-sectional crank shape. On the outer peripheral surface, which is the detected surface of the encoder 4b, portions magnetized in the N pole (first characteristic portion) and portions magnetized in the S pole (second characteristic portion) are alternately arranged in the circumferential direction. And it arranges at equal intervals. The boundary line between the portion magnetized in the N pole and the portion magnetized in the S pole is a straight line inclined at the same angle in the same direction with respect to the axial direction of the encoder 4b. The detection parts of the pair of sensors 5 and 5 are placed close to and opposed to the upper and lower ends of the outer peripheral surface of the encoder 4b. That is, the sensors 5 and 5 are supported and fixed at both upper and lower ends of the inner peripheral surface of the cover 7 that is attached to the inner end opening of the outer ring 1 that is a stationary side race, and the detection of the sensors 5 and 5 is performed. The portion is made to face and oppose the upper and lower end portions of the outer peripheral surface of the encoder 4b. 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 5 and 5.

  In the case of a rolling bearing unit for supporting a wheel of an automobile, the axial load applied between the outer ring 1 and the hub 2 is input from the ground contact surface between the outer peripheral surface of the wheel (tire) coupled to the hub 2 and the road surface. The Since this ground contact surface exists radially outward from the rotation center of the outer ring 1 and the hub 2, the axial load is not between the outer ring 1 and the hub 2 but as a pure axial load. 1 and the center axis of the hub 2 and the center of the grounding surface are applied with a moment in a virtual plane (in the vertical direction). The magnitude of this moment is proportional to the magnitude of the axial load input from the ground plane. Therefore, if this moment is obtained, this axial load can be obtained. On the other hand, when a moment is applied to the hub 2, the upper end of the encoder 4b is displaced in any direction with respect to the axial direction, and the lower end is similarly displaced in the opposite direction. As a result, the phases of the output signals of the sensors 5 and 5 in which the detection units are brought close to and opposed to the upper and lower ends of the outer peripheral surface of the encoder 4b are shifted in opposite directions with respect to the neutral positions. Therefore, based on the direction and magnitude of the phase shift of the output signals of these sensors 5, 5, the direction and magnitude of the axial relative displacement between the outer ring 1 and the hub 2, and the outer ring 1 and An axial load acting between the hub 2 and the hub 2 is obtained.

  Next, FIGS. 13 to 14 show a third example of the prior invention disclosed in Japanese Patent Application No. 2005-147642. In the case of the third example of the present invention, an encoder 4c configured in a cylindrical shape by a permanent magnet is fitted and fixed to an intermediate portion of the hub 2 that is a rotation side raceway, and the axial direction of the outer ring 1 that is a stationary side raceway. A sensor 5 is provided between the rolling elements 3 and 3 arranged in a double row at the intermediate portion in a state where the detection portion is in close proximity to the outer peripheral surface of the encoder 4c which is a detection surface. Note that a magnetic sensing element such as a Hall IC, a Hall element, an MR element, or a GMR element is incorporated in the detection portion of the sensor 5.

  As shown in FIG. 14, on the outer circumferential surface of the encoder 4c, there are a portion magnetized in the N pole (first characteristic portion) and a portion magnetized in the S pole (second characteristic portion) in the circumferential direction. They are arranged alternately and at equal intervals. The boundary line between the part magnetized in the N pole and the part magnetized in the S pole is a straight line inclined by a predetermined angle with respect to the axial direction of the encoder 4c, and each boundary adjacent in the circumferential direction. The inclination directions with respect to the axial direction are reversed between the lines. As a result, the width in the circumferential direction of the portion magnetized in the N pole is made wider toward one axial side {lower side in FIG. 14B), and in the circumferential direction of the portion magnetized in the S pole. The width is made wider toward the other side in the axial direction (upper side in FIG. 14B).

  In the case of the third example of the prior invention 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. Accordingly, the duty ratio (high potential duration / one cycle) of the output signal of the sensor 5 changes. Therefore, based on the duty ratio, the direction and magnitude of the relative displacement in the axial direction and the direction and magnitude of the axial load can be obtained.

  As described above, in the case of the first to third examples of the prior invention, since the relative displacement amount and the load, which are the state quantities, can be obtained based on the phase difference or duty ratio of the output signals of the sensors 5, 5, the state It is possible to sufficiently reduce the cost and ensure durability of the quantity measuring device. By the way, although the state quantity measuring apparatus of the 1st-3rd example of the prior invention mentioned above is a structure which uses cylindrical encoder 4a, 4b, 4c, as a state quantity measuring apparatus other than this, as FIG. A structure using annular encoders 8a, 8b, and 8c as shown in FIG.

  Of the encoders 8a, 8b, and 8c shown in FIGS. 15 to 17, the encoder 8a shown in FIG. 15 has a configuration in which the cylindrical encoder 4a shown in FIGS. Is. That is, the encoder 8a is formed in a ring shape as a whole by a permanent magnet, and a portion (first characteristic portion) magnetized with an N pole on one side (front surface of FIG. 15) as a detection surface and S The parts magnetized in the poles (second characteristic parts) are alternately arranged at equal intervals in the circumferential direction. The boundary line between the part magnetized in the N pole and the part magnetized in the S pole is linear at both radial side parts with the radial intermediate part of the encoder 8a as a boundary. The inclination angles (absolute values) with respect to the radial direction are equal to each other, and the inclination directions with respect to the radial direction are opposite to each other. That is, the boundary line has a “<” shape with a radially intermediate portion protruding most on one side in the circumferential direction.

  Such an encoder 8a is supported and fixed to the rotating member concentrically with the rotating member. At the same time, as shown in FIG. 15, a pair of sensors 5 and 5 supported by a stationary member is disposed on a portion (upper portion in the illustrated example) of one side surface of the encoder 8a having the same phase in the circumferential direction. The detectors are placed close to each other while being shifted in the radial direction (vertical direction). In addition, the portion where the inclination direction of each boundary line changes in a state where no load acts between the stationary member and the rotating member is just at the center position between the detecting portions of the sensors 5 and 5. The installation position of each member is regulated so that it exists. In this state, based on the fact that a load acts between the stationary member and the rotating member (the stationary member and the rotating member are relatively displaced), the encoder 8a has a diameter relative to the sensors 5 and 5. When displaced in the direction (vertical direction), a phase difference occurs between the output signals of the sensors 5 and 5. Therefore, based on this phase difference, the direction and magnitude of relative displacement between the stationary member and the rotating member, and the direction and magnitude of the load acting between these two members are determined.

  Further, the encoder 8b shown in FIG. 16 has a configuration in which the cylindrical encoder 4b shown in FIG. 12 is formed into a ring shape. That is, the encoder 8b is formed into a ring shape as a whole by a permanent magnet, and a portion (first characteristic portion) magnetized with an N pole on one side (front surface of FIG. 16), which is a detected surface, and S The parts magnetized in the poles (second characteristic parts) are alternately arranged at equal intervals in the circumferential direction. The boundary line between the part magnetized in the N pole and the part magnetized in the S pole is a straight line inclined at the same angle in the same direction with respect to the radial direction of the encoder 8b. Such an encoder 8b is also supported and fixed to the rotating member concentrically with the rotating member. At the same time, as shown in FIG. 16, a pair of encoders 8b is supported by a stationary member at two locations (upper and lower locations in the illustrated example) that are 180 degrees apart from each other in the circumferential direction. The detection parts of the sensors 5 and 5 are placed close to each other. In this state, based on the fact that a load acts between the stationary member and the rotating member (the stationary member and the rotating member are relatively displaced), the encoder 8a has a diameter relative to the sensors 5 and 5. When displaced in the direction (vertical direction), a phase difference occurs between the output signals of the sensors 5 and 5. Therefore, based on this phase difference, the direction and magnitude of relative displacement between the stationary member and the rotating member, and the direction and magnitude of the load acting between these two members are determined.

  The encoder 8c shown in FIG. 17 has a configuration in which the cylindrical encoder 4c shown in FIG. 14 is formed into a ring shape. That is, the encoder 8c is formed into a ring shape as a whole by a permanent magnet, and a portion (first characteristic portion) magnetized with an N pole on one side (front surface of FIG. 17) which is a detected surface and S The parts magnetized in the poles (second characteristic parts) are alternately arranged at equal intervals in the circumferential direction. The boundary line between the part magnetized in the N pole and the part magnetized in the S pole is a straight line inclined by a predetermined angle with respect to the radial direction of the encoder 8c, and the boundary lines adjacent to each other in the circumferential direction. The inclination directions with respect to the radial direction are opposite to each other. Thereby, the width in the circumferential direction of the portion magnetized in the N pole is increased toward the inner diameter side, and the width in the circumferential direction of the portion magnetized in the S pole is increased in the outer diameter side. Such an encoder 8c is also supported and fixed to the rotating member concentrically with the rotating member. At the same time, as shown in FIG. 17, the detection portion of the sensor 5 supported by the stationary member is brought close to and opposed to a part in the circumferential direction (upper part in the illustrated example) on one side surface of the encoder 8c. In this state, based on the fact that a load acts between the stationary member and the rotating member (the stationary member and the rotating member are displaced relative to each other), the encoder 8c moves in the radial direction (up and down) with respect to the sensor 5. Displacement in the direction), the duty ratio (high potential duration / one cycle) of the output signal of the sensor 5 changes. Therefore, based on this duty ratio, the direction and magnitude of relative displacement between the stationary member and the rotating member, and the direction and magnitude of the load acting between these members can be obtained.

  However, in the case of the annular encoders 8a, 8b, and 8c as described above, the shape of each side or the whole of the boundary line between the portion magnetized at the N pole and the portion magnetized at the S pole on the detected surface. Is a linear shape. In other words, a proportional relationship is not established between the radial position and the central angle position regarding each side or the whole of the boundary line. Therefore, the radial displacement amount (relative displacement amount between the stationary member and the rotating member) of the encoders 8a, 8b, and 8c with respect to the sensors 5 and 5 and the phase difference between the output signals of the sensors 5 and 5 or A proportional relationship is not established with the duty ratio. Even when the proportional relationship is not established in this way, if a map showing the relationship between the phase difference or duty ratio and the radial displacement amount is prepared in advance, the map can be used to calculate the phase difference or duty ratio. From the above, the radial displacement amount can be obtained. However, if the opposing positions of the detection parts of the sensors 5 and 5 with respect to the detection surfaces of the encoders 8a, 8b, and 8c are shifted in the radial direction from the design position due to assembly errors or the like, the map is used. Thus, the amount of radial displacement cannot be accurately obtained. On the other hand, when a proportional relationship is established between the phase difference or duty ratio and the radial displacement amount, the radial displacement amount is calculated from the phase difference or duty ratio without using a map. Is easily required. Furthermore, even when the position where the detection unit faces the detected surface is displaced in the radial direction from the design position due to an assembly error or the like, the initial phase difference or duty ratio after assembly (when no load is applied) Is set to the zero point, the amount of radial displacement can be accurately obtained from this phase difference or duty ratio during operation. Therefore, it is desirable to realize a structure in which a proportional relationship is established between the phase difference or duty ratio and the radial displacement.

JP 2001-21577 A Japanese Patent Laid-Open No. 3-209016 Japanese Patent Laid-Open No. 2004-3918 Japanese Patent Publication No.62-3365

  In view of the circumstances as described above, the encoder and the state quantity measuring device of the present invention establish a proportional relationship between the phase difference or duty ratio of the output signal of each sensor and the radial displacement of the encoder with respect to each sensor. It was invented to realize a structure that can be made.

Of the encoder and the state quantity measuring apparatus according to the present invention, the encoder according to claim 1 is supported and fixed to a part of the rotating member during use, and an annular detection surface concentric with the rotation center of the rotating member. Is provided. Then, the first characteristic part and the second characteristic part having different characteristics on the detected surface are alternately arranged in the circumferential direction, and the boundary line between the first characteristic part and the second characteristic part It is constituted by a curve in which a proportional relationship is established between the direction position and the center angle position.
This curve is a curve C as shown in FIG. 1 represented by the following equations (1) and (2), for example.
x = r · cos (α · r) ----- (1)
y = r · sin (α · r) ----- (2)
The meanings of the symbols on the right side of the equations (1) and (2) are as follows.
r: distance from the coordinate origin O (the radial position of each point constituting the curve C)
α · r: angle based on x-axis (center angle position of each point constituting curve C)
α: Arbitrary constant (proportional coefficient between radial position and center angle position with respect to curve C)

When the encoder according to the first aspect is implemented, specifically, as described in the second aspect, for example, the proportionality coefficient between the radial position and the central angle position with respect to each boundary line is set as follows. These two boundary lines are made different from each other in the radial direction between the radial intermediate portions of these boundary lines (for example, the absolute values are made equal and the signs of the positive and negative signs are reversed) A configuration is adopted in which the proportional coefficients for the respective parts are equal to each other.
Alternatively, as described in claim 3, for example, the proportionality coefficient between the radial position and the central angle position with respect to each boundary line is made equal over the entire length of each boundary line, and Therefore, a configuration is adopted in which the proportional coefficients are equal to each other.
Alternatively, for example, as described in claim 4, the proportionality coefficient between the radial position and the central angular position with respect to each boundary line is made equal over the entire length of each boundary line, and the proportionality coefficients are mutually equal. A configuration is adopted in which two different types of boundary lines (for example, the absolute values are equal but the signs of the positive and negative signs are opposite) are alternately arranged in the circumferential direction.

Further, among the encoder and the state quantity measuring device of the present invention, the state quantity measuring device according to claim 5 includes an encoder and at least one pair of sensors.
Of these, the encoder is supported and fixed to the rotating member.
Each of the pair of sensors is supported by a stationary member in a state in which the detection portion faces a part of the detection surface of the encoder. At the same time, the output is changed in response to a change in the characteristics of the detected surface facing the detection unit.
Further, the encoder is the encoder according to claim 2 described above, and among the detected surfaces of the encoder, both sides in the radial direction have mutually different phases in the circumferential direction and have different proportionality coefficients in each boundary line. The detection portions of the pair of sensors are made to face each other at two locations existing in the region. Based on the phase difference between the output signals of both sensors, the state quantity between the rotating member and the stationary member {relative displacement (radial displacement, axial displacement, tilt), load (radial load) , Axial load, moment). same as below. } Can be measured.

According to a sixth aspect of the present invention, there is provided a state quantity measuring device comprising an encoder and at least one pair of sensors.
Of these, the encoder is supported and fixed to the rotating member.
Each of the pair of sensors is supported by a stationary member in a state in which the detection portion faces a part of the detection surface of the encoder. At the same time, the output is changed in response to a change in the characteristics of the detected surface facing the detection unit.
The encoder is the encoder according to claim 3 described above, and the detection units of the pair of sensors are arranged at two positions on the detected surface of the encoder that are 180 degrees different in phase in the circumferential direction. They are facing each other. Then, based on the phase difference between the output signals of these two sensors, the state quantity between the rotating member and the stationary member can be measured.

According to a seventh aspect of the present invention, there is provided a state quantity measuring device comprising an encoder and at least one sensor.
Of these, the encoder is supported and fixed to the rotating member.
The sensor is supported by a stationary member in a state where the detection portion faces a part of the detection surface of the encoder. At the same time, the output is changed in response to a change in the characteristics of the detected surface facing the detection unit.
The encoder is the encoder described in claim 4 described above, and the state quantity between the rotating member and the stationary member can be measured based on the duty ratio of the output signal of the sensor.

Further, when the state quantity measuring device described in claims 5 to 7 described above is implemented, specifically, as described in claim 8, for example, the rotating member is configured to be a rolling bearing unit and rotated during use. A rotating bearing ring or a member that is coupled and fixed to the rotating bearing ring, and the stationary member is a stationary bearing ring that does not rotate even when used by constituting the rolling bearing unit or a member that supports and fixes the stationary bearing ring. And
More specifically, for example, as described in claim 9, the rolling bearing unit is configured to support the wheel of an automobile so as to be rotatable with respect to the suspension device.

  As described above, in the case of the encoder according to the present invention, a proportional relationship is established between the radial position and the central angle position of the boundary line between the first characteristic portion and the second characteristic portion provided on the detected surface. It is composed of curved lines. For this reason, in the case of the state quantity measuring apparatus of the present invention as described above configured by incorporating such an encoder, the phase difference between the output signals of a pair of sensors (in the case of claims 5 and 6) or 1 A proportional relationship is established between the duty ratios of the output signals of the two sensors (in the case of claim 7) and the radial displacements of the encoder relative to these sensors (the relative displacements of the stationary member and the rotating member). I can do things. For this reason, the relative displacement amount can be easily obtained from the phase difference or the duty ratio without using a map during operation. Even if the position of the detection portion of each sensor with respect to the detection surface of the encoder deviates from the design position in the radial direction due to an assembly error or the like, the initial position (when no load is applied) after assembly is provided. If the phase difference or duty ratio is set to a zero point, the relative displacement can be accurately obtained from the phase difference or duty ratio during operation.

[First example of embodiment]
2 to 4 show a first example of an embodiment of the present invention corresponding to claims 1, 2, 5, 8 and 9. The feature of this example is that the annular encoder 8d has the same basic configuration as the encoder 8a shown in FIG. 15 described above, and a plurality of “<”-shaped boundary lines existing on the detection surface. These are that the shape of each side is changed from a linear shape to a predetermined curved shape, and that the encoder 8d is assembled to a specific wheel support rolling bearing unit. Since the structure and operation of other parts such as the positions of the detection parts of the sensors 5 and 5 facing the detection surface are the same as the structure shown in FIG. 15 described above, the overlapping description is omitted or simplified. Hereinafter, the description will focus on the features of this example.

  In the case of this example, as shown in FIG. 2, a combination seal that seals between the inner peripheral surface of the inner end of the outer ring 1 that is a stationary side raceway and the outer peripheral surface of the inner end of the hub 2 that is a rotary side raceway. The encoder 8d is attached and fixed concentrically with the hub 2 on the inner surface of the slinger 10 that is fitted and fixed to the inner end of the hub 2 constituting the ring 9. In this state, the inner side surface of the encoder 8d is set as a detected surface. A sensor unit 11 holding the pair of sensors 5 and 5 is supported on the upper end of a cover 7 attached to the inner end of the outer ring 1.

  In the case of the encoder 8a shown in FIG. 15 described above, each side of a plurality of "<"-shaped boundary lines existing on the detected surface is a straight line, whereas in the case of the encoder 8d of this example, As shown in FIG. 3, each side of a plurality of “<”-shaped boundary lines existing on the detected surface is represented by a curve {radial position in the above-mentioned formulas (1) and (2), respectively. Between r and the center angle position (α · r), a curve that establishes a proportional relationship with a proportionality coefficient α is used. More specifically, the absolute value of the proportionality coefficient α is made equal to and proportional to the side existing in the radially outer half of each boundary line and the side existing in the radially inner half. The sign of the coefficient α is opposite to each other. This point will be described in more detail with reference to FIG. This FIG. 4 shows a plurality of two types of curves in which the absolute value of the proportional coefficient α is equal to each other and the signs of the proportional coefficient α are opposite to each other. It is the figure plotted at equal intervals. In the case of this example, a part of each of these two types of curves (for example, a part surrounded by a chain line S) is used as each side constituting each boundary line.

  The operation of the encoder and state measuring apparatus of this example configured as described above is as follows. As described above, in the case of a rolling bearing unit for supporting a wheel of an automobile, the axial load input between the outer ring 1 and the hub 2 from the contact surface between the tire and the road surface is not a pure axial load, It is applied with a moment in a virtual plane (in the vertical direction) including the center of the ground plane and the central axes of the outer ring 1 and the hub 2. The magnitude of this moment is proportional to the magnitude of the axial load. Therefore, if this moment is obtained, this axial load can be obtained. On the other hand, when the moment is applied to the hub 2, the central axis of the hub 2 is inclined with respect to the central axis of the outer ring 1 in the imaginary plane (in the vertical direction). The center of this inclination is substantially the center of the bearing unit. For this reason, when the moment is applied to the hub 2, the encoder 8 d supported and fixed to the inner end portion of the hub 2 via the slinger 10 in the radial direction (vertical direction) with respect to the sensors 5 and 5. Displace. As a result, a phase difference is generated between the output signals of the sensors 5 and 5 in which the respective detection units are brought close to and opposed to the inner surface of the encoder 8d. Therefore, based on the phase difference between the output signals of both the sensors 5 and 5, the direction and magnitude of the axial relative displacement between the outer ring 1 and the hub 2, and between the outer ring 1 and the hub 2. The acting axial load is required.

  In particular, in the case of this example, each side of a plurality of “<”-shaped boundary lines provided on the inner surface of the encoder 8d is proportional to the radial position and the central angle position as described above. It is a curve that establishes the relationship. For this reason, in the case of the state quantity measuring apparatus of this example configured by incorporating such an encoder 8d, the phase difference between the output signals of the two sensors 5, 5 and the encoder 8d for both the sensors 5, 5 are described. A proportional relationship can be established between the vertical displacement amount (the relative displacement amount in the axial direction between the outer ring 1 and the hub 2). Therefore, the relative displacement amount in the axial direction can be easily obtained from the phase difference without using a map during operation. Further, even when the opposing position of the detecting portions of the sensors 5 and 5 with respect to the inner surface of the encoder 8d is shifted in the vertical direction from the design position due to an assembly error or the like, the initial (after no load is applied) after assembly. If the phase difference is set to zero, the relative displacement amount in the axial direction can be accurately obtained from this phase difference during operation.

In the first example of the above-described embodiment, the detection portions of the sensors 5 and 5 are opposed to the upper portion of the inner surface of the encoder 8d. The same effect can be obtained even when facing the lower part of the inner surface of 8d. The combination of the encoder 8d and the pair of sensors 5, 5 can also be used by being assembled with another rotation support device. Regardless of which rotation support device is assembled, if the detection parts of the sensors 5 and 5 are closely opposed to the detection surface of the encoder 8d in the radial direction of the detection surface, the both sensors From the phase difference between the output signals of the sensors 5 and 5, the radial displacement of the encoder 8d with respect to the shifted direction can be measured.

[Second Example of Embodiment]
Next, FIG. 5 shows a second example of an embodiment of the present invention corresponding to claims 1, 3, 6, 8 and 9. The feature of this example is that the annular encoder 8e has the same basic configuration as the encoder 8b shown in FIG. 16, and a plurality of boundary lines existing on the detection surface are linearly shaped. The point is to use what is changed to a predetermined curve shape. The opposing positions of the detection portions of the sensors 5 and 5 with respect to the detected surface are the same as the structure shown in FIG. 16, and the encoder 8e is attached and fixed to the inner surface of the slinger 10 (FIG. 2). At the same time, the point that the sensors 5 and 5 are supported by the cover 7 (FIG. 2) is the same as that of the first example of the embodiment described above. For this reason, overlapping illustrations and descriptions will be omitted or simplified, and the following description will focus on the features of this example.

  In the case of the encoder 8b shown in FIG. 16 described above, each side of the plurality of boundary lines existing on the surface to be detected is a straight line, whereas in the case of the encoder 8e in this example, the surface to be detected is A plurality of boundary lines existing on a certain inner side surface (front surface of FIG. 5) are respectively expressed by the curves {radial position r and central angle position (α · r) In the meantime, a curve in which a proportionality relationship is established with a proportionality coefficient α is set. That is, in the case of this example, among the two types of curves shown in FIG. 4 described above, a part of a plurality of curves each of which is the same type (for example, a portion surrounded by a chain line T) is respectively The boundary is used.

  In the case of the encoder and the state measuring apparatus of the present example configured as described above, when a moment is applied to the hub 2 (FIG. 2), the encoder 8e causes each of the above-described encoders to be similar to the case of the first example of the above-described embodiment. The sensor 5 or 5 is displaced in the radial direction (vertical direction). As a result, a phase difference is generated between the output signals of the sensors 5 and 5 in which the respective detection units are brought close to and opposed to the inner surface of the encoder 8e. Therefore, based on the phase difference between the output signals of both the sensors 5 and 5, the direction and magnitude of the axial relative displacement between the outer ring 1 (FIG. 2) and the hub 2, and the outer ring 1 and the hub 2 The axial load acting during the period is required. In particular, in the case of this example, the plurality of boundary lines provided on the inner surface of the encoder 8e are curves that establish a proportional relationship between the radial position and the central angle position, as described above. For this reason, in the case of the state quantity measuring apparatus of this example configured by incorporating such an encoder 8e, the phase difference between the output signals of the sensors 5, 5 and the encoder 8e for the sensors 5, 5 are described. A proportional relationship can be established between the vertical displacement amount (the relative displacement amount in the axial direction 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 described above.

  In the case of the combination of the encoder 8e and the sensors 5 and 5 of the second example of the embodiment described above, not only when the encoder 8e is displaced in the vertical direction with respect to both the sensors 5 and 5, Even when displaced in the left-right direction, the phase difference between the output signals of the sensors 5, 5 changes. For this reason, the combination of the encoder 8e and the sensors 5 and 5 is a combination of a stationary member (outer ring 1) and a wheel bearing rolling bearing unit (see FIG. 2) constituting the second example of the embodiment described above. It is preferable to incorporate the rotating member (hub 2) in a structure that does not substantially displace in the left-right direction in FIG. 5 in order to ensure the measurement accuracy of the amount of displacement in the up-down direction. FIG. 6 shows a conventionally known annular encoder 12 in which a plurality of boundary lines existing on the surface to be detected are straight lines in the radial direction. Also in the case of the encoder 12, if the detection portions of a pair of sensors are opposed to the left and right side portions of the detection surface of the encoder 12, the encoder 12 for the two sensors is determined based on the phase difference between the output signals of the two sensors. The amount of displacement in the vertical direction is obtained. However, in the case of the encoder 12, even if the detection parts of the two sensors are opposed to the upper and lower side portions of the detection surface of the encoder 12, the phase difference between the output signals of the two sensors causes the above-described difference to the two sensors. The amount of vertical displacement of the encoder 12 cannot be obtained. On the other hand, in the case of the encoder 8e of the second example of the above-described embodiment, even if the sensors 5 and 5 cannot be arranged on the left and right sides of the detection surface, If 5 can be arranged, there is an advantage that the amount of displacement in the vertical direction of the encoder 8e with respect to both the sensors 5 and 5 can be obtained.

[Third example of embodiment]
Next, FIG. 7 shows a third example of the embodiment of the invention corresponding to claims 1, 4, 7, 8 and 9. The feature of this example is that the annular encoder 8f has the same basic configuration as the encoder 8c shown in FIG. 17 described above, and a plurality of boundary lines existing on the detection surface are linearly shaped. The point is to use what is changed to a predetermined curve shape. The opposing position of the detection portion of the sensor 5 with respect to the detected surface is the same as the structure shown in FIG. 17, and the encoder 8f is attached and fixed to the inner surface of the slinger 10 (FIG. 2). The point of supporting the sensor 5 on the cover 7 (FIG. 2) is the same as in the case of the first example of the embodiment described above. For this reason, overlapping illustrations and descriptions will be omitted or simplified, and the following description will focus on the features of this example.

  In the case of the encoder 8c shown in FIG. 17 described above, each side of the plurality of boundary lines existing on the detected surface is a straight line, whereas in the case of the encoder 8f of this example, the detected surface is A plurality of boundary lines existing on a certain inner side surface (front surface of FIG. 7) are respectively expressed by the curves {radial position r and central angle position (α · r) In the meantime, a curve in which a proportionality relationship is established with a proportionality coefficient α is set. Specifically, in the case of this example, a part of each of the two types of curves shown in FIG. 4 (for example, a part surrounded by a chain line U) is used as each boundary line adjacent in the circumferential direction. Yes.

  Also in the case of the encoder and the state measuring device of this example configured as described above, when a moment is applied to the hub 2 (FIG. 2), the encoder 8f is connected to the sensor as in the case of the first example of the embodiment described above. 5 is displaced in the radial direction (vertical direction). As a result, the duty ratio of the output signal of the sensor 5 is changed, with the detection unit being brought close to and opposed to the inner surface of the encoder 8f. Therefore, based on the duty ratio, the direction and magnitude of the axial relative displacement between the outer ring 1 (FIG. 2) and the hub 2 and the axial load acting between the outer ring 1 and the hub 2 are obtained. It is done. In particular, in the case of this example, the plurality of boundary lines provided on the inner surface of the encoder 8f are curves that have a proportional relationship between the radial position and the central angle position as described above. For this reason, in the case of the state quantity measuring device of this example configured by incorporating such an encoder 8f, the duty ratio of the output signal of the sensor 5 and the amount of vertical displacement of the encoder 8f with respect to the sensor 5 are described. A proportional relationship can be established between (the relative displacement in the axial direction between the outer ring 1 and the hub 2). Other configurations and operations are the same as those of the first example of the embodiment described above.

  In each of the embodiments described above, as a ring-shaped encoder, the first characteristic portion made of a permanent magnet and provided on the detection surface (side surface) is a portion magnetized to the N pole, and the second characteristic portion is What was made into the part magnetized to S pole was adopted. However, when carrying out the present invention, the annular encoder is made of a simple magnetic material, and the first characteristic portion provided on the detected surface (side surface) is a convex portion (or column portion), and the second characteristic portion It is also possible to adopt a material having a recess (or a through hole). When such a simple encoder made of a magnetic material is used, a permanent magnet is provided on the sensor side. Moreover, when implementing this invention, the total number of the 1st characteristic part and 2nd characteristic part which are provided in the to-be-detected surface of an encoder does not ask | require in particular. For example, the number may be more than ten or more than one hundred.

Further, in each of the above-described embodiments, the relative displacement amount (inclination) in the axial direction between the stationary member and the rotating member, and the relationship between the stationary member and the rotating member from the phase difference or duty ratio of the output signals of the sensors. A configuration was adopted to determine the axial load (moment) acting in between. However, when carrying out the present invention, the radial direction between the stationary member and the rotating member is determined from the phase difference or duty ratio of the output signals of each sensor by supporting and fixing the encoder to the rotating member that receives a pure radial load. the relative displacement, as well, it is also possible to adopt a configuration for determining a radial load acting between the these stationary member rotating member.

  Further, as described above, according to the state quantity measuring device of the present invention, the relative displacement amount between the stationary member and the rotating member, and the stationary member and the rotating member based on the phase difference or duty ratio of the output signals of the sensors. Both the load acting between the members and the member can be obtained. In this case, after obtaining the relative displacement amount, the load can be obtained by using the relative displacement amount, or directly obtained from the phase difference or the duty ratio. Regardless of which method is used, there is no proportional relationship between the phase difference, duty ratio, relative displacement, and load, so use a map that shows the relationship between the two. Thus, the above load is obtained. However, in the present invention, a proportional relationship is established between the phase difference or duty ratio and the radial displacement amount (relative displacement amount) of the encoder with respect to each sensor. Gain large. Therefore, the measurement accuracy of the load can be improved.

The figure which shows the curve which is a curve which comprises the boundary line provided in the to-be-detected surface of the encoder of this invention, and a proportional relationship is materialized between a radial direction position and a center angle position. The half part sectional view showing the structure of the 1st example of an embodiment of the invention. The figure which looked at the encoder and the sensor from the axial direction inner side. A plurality of two types of curves, each having an absolute value of the proportionality coefficient between the radial position and the central angle position, and the signs of the proportionality coefficient being opposite to each other, each inside the circle The figure plotted at equal intervals about the circumferential direction. The figure similar to FIG. 3 which shows the 2nd example of embodiment of this invention. The figure which looked at the annular-shaped encoder for rotational speed detection conventionally known from the axial direction. The figure similar to FIG. 3 which shows the 3rd example. Sectional drawing which shows the structure of the 1st example of a prior invention. The perspective view of an encoder. The expanded view of the to-be-detected surface of an encoder. The diagram which shows the output signal of the sensor which changes with the fluctuation | variation of an axial load. Sectional drawing which shows the structure of the 2nd example of a prior invention. Sectional drawing which shows the structure of the same 3rd example. The encoder is shown, (A) is a raw material, (B) is a perspective view of a finished product. The figure which looked at the axial direction from the to-be-detected surface side of this encoder of the 1st example of a ring-shaped encoder considered in the process of completing this invention, and a pair of sensor. Similarly, the figure which looked at the 2nd example of a ring-shaped encoder and a pair of sensors from the to-be-detected surface side of this encoder to the axial direction. Similarly, the figure which looked at the 3rd example of a ring-shaped encoder and one sensor from the to-be-detected surface side of this encoder in the axial direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer ring 2 Hub 3 Rolling element 4a, 4b, 4c Encoder 5 Sensor 6 Support ring 7 Cover 8a-8f Encoder 9 Combination seal ring 10 Slinger 11 Sensor unit 12 Encoder

Claims (9)

  A first characteristic portion and a second characteristic that are supported and fixed to a part of the rotating member during use, and have a ring-shaped detected surface concentric with the rotation center of the rotating member, and having different characteristics on the detected surface Are arranged alternately with respect to the circumferential direction, and the boundary line between the first characteristic part and the second characteristic part is configured by a curve that establishes a proportional relationship between the radial position and the central angle position. Encoder.   The proportionality factor between the radial position and the central angle position for each boundary line is different from each other between the two radial side portions with the boundary between the radial intermediate portions of each boundary line. The encoder according to claim 1, wherein the proportional coefficients for the respective parts are equal to each other.   The proportionality coefficient between the radial position and the central angular position for each boundary line is made equal over the entire length of each boundary line, and the proportionality coefficient is made equal between the boundary lines. The encoder according to claim 1.   The proportional coefficient between the radial position and the central angle position for each boundary line is made equal over the entire length of each boundary line, and two types of boundary lines having different proportional coefficients are alternately arranged in the circumferential direction. The encoder according to claim 1, wherein the encoder is arranged.   Encoders supported and fixed to the rotating member, and supported by the stationary member with the detection unit facing a part of the detection surface of the encoder, and the detection surface facing the detection unit And at least one pair of sensors that change the output in response to a change in characteristics. The encoder is the encoder according to claim 2, and the phase in the circumferential direction of the detected surface of the encoder is The detection parts of the pair of sensors are opposed to each other at two locations that are equal to each other and have different proportionality coefficients for each boundary line in regions on both sides in the radial direction. A state quantity measuring device capable of measuring a state quantity between the rotating member and the stationary member based on a phase difference.   Encoders supported and fixed to the rotating member, and supported by the stationary member with the detection unit facing a part of the detection surface of the encoder, and the detection surface facing the detection unit And at least one pair of sensors that change their outputs in response to changes in characteristics, wherein the encoder is the encoder according to claim 3, and the phases in the circumferential direction of the detected surfaces of the encoder are mutually different. The detection units of the pair of sensors are opposed to each other at two positions that differ by 180 degrees, and the state quantity between the rotating member and the stationary member is determined based on the phase difference between the output signals of these sensors. A state quantity measuring device that enables measurement.   The encoder supported and fixed to the rotating member, and supported by the stationary member with the detection unit facing a part of the detection surface of the encoder, and the characteristics of the detection surface facing the detection unit And at least one sensor that changes its output in response to a change, wherein the encoder is the encoder according to claim 4, and the rotating member and the stationary member are based on a duty ratio of an output signal of the sensor. A state quantity measuring device that makes it possible to measure a state quantity between and.   The rotating member is a rotating bearing ring that constitutes a rolling bearing unit and rotates during use, or a member that is coupled and fixed to the rotating bearing ring, and the stationary member does not rotate even when used by constituting the rolling bearing unit. The state quantity measuring device according to any one of claims 5 to 7, which is a stationary raceway or a member that supports and fixes the stationary raceway.   The state quantity measuring device according to claim 8, wherein the rolling bearing unit rotatably supports the wheel of the automobile with respect to the suspension device.

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