JP2007071641A - State quantity measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve an inexpensive structure allowing the behavior of an encoder 14 to be measured by a sensor with high reliability by increasing the density of magnetic flux passing through a surface to be detected of the encoder 14 containing a permanent magnet 15 sufficiently across the width direction of the surface to be detected and at low cost. <P>SOLUTION: The thickness of the permanent magnet 15 at the end part in the width direction of the surface to be detected is set to be larger than the thickness of the permanent magnet 15 at the central part in the width direction of the surface to be detected. For that purpose, the cross-sectional shape of the surface to be detected of the permanent magnet 15 is formed in a straight line, and a part connecting the end part in the width direction of the permanent magnet 15 out of a support tubular part 18 constituting a support plate 16 supporting the permanent magnet 15 is depressed in a direction away from the surface to be detected as compared to a part connecting the central part in the width direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The state quantity measuring device according to the present invention is incorporated in a wheel bearing rolling bearing unit that supports a vehicle (automobile) wheel rotatably with respect to a suspension device, for example, and measures the magnitude of a load applied to the wheel, Used to ensure stable operation of vehicles.

  For example, a rolling bearing unit is used to rotatably support a vehicle wheel with respect to a suspension device. In order to ensure the running stability of the vehicle, a running state stabilizing device for the vehicle such as an antilock brake system (ABS) or a traction control system (TCS) is widely used. According to these running state stabilizing devices such as ABS and TCS, the running state of the vehicle at the time of braking or acceleration can be stabilized, but in order to ensure this stability even under more severe conditions, the vehicle It is necessary to control the brakes and the engine by incorporating more information that affects the running stability of the vehicle.

  That is, in the case of the conventional running state stabilizing device such as ABS or TCS, since so-called feedback control is performed to detect the slip between the tire and the road surface and control the brake and the engine, the brake and engine Control is delayed for a moment. In other words, in order to improve performance under severe conditions, the so-called feed-forward control prevents slippage between the tire and the road surface, or the so-called brake one-side effect where the braking forces of the left and right wheels are extremely different. Cannot be prevented.

  In order to cope with such a problem, in order to perform the feedforward control or the like, one of a radial load and an axial load applied to the wheel is applied to the rolling bearing unit for supporting the wheel with respect to the suspension device. Or it is possible to incorporate a load measuring device for measuring both. Conventionally, what was described in patent documents 1-5 is known as a wheel bearing rolling bearing unit with a load measuring device which can be used in such a case.

  Of these, Patent Document 1 describes a rolling bearing unit with a load measuring device capable of measuring a radial load. In the case of the first example of the conventional structure, the outer ring and the hub are measured by measuring the radial displacement between the outer ring that does not rotate and the hub that rotates on the inner diameter side of the outer ring by a non-contact displacement sensor. The radial load applied between and is calculated. The obtained radial load is used not only to properly control the ABS but also to inform the driver of a bad loading condition.

  Patent document 2 describes a structure for measuring an axial load applied to a rolling bearing unit. In the case of the second example of the conventional structure described in Patent Document 2, bolts for connecting the fixed side flange to the knuckle are screwed at a plurality of positions on the inner side surface of the fixed side flange provided on the outer peripheral surface of the outer ring. Each load sensor is attached to a portion surrounding the screw hole. Each load sensor is clamped between the outer surface of the knuckle and the inner surface of the fixed flange in a state where the outer ring is supported and fixed to the knuckle. In the case of the load measuring device for the rolling bearing unit of the second example having such a conventional structure, the axial load applied between the wheel and the knuckle is measured by the load sensors.

  Further, in Patent Document 3, the displacement sensor unit supported at four positions in the circumferential direction of the outer ring and the L-shaped detection ring that is externally fitted and fixed to the hub are used to detect the above-described outer ring at the four positions. A structure is described in which the displacement of the hub in the radial direction and the axial direction is detected, and the direction of the load applied to the hub and the magnitude thereof are determined based on the detection values of the respective parts.

  Further, in Patent Document 4, a strain gauge for detecting dynamic strain is provided in a member corresponding to an outer ring whose rigidity is partially reduced, and the revolution speed of the rolling element is determined from the passing frequency of the rolling element detected by the strain gauge. A method for determining the axial load applied to the rolling bearing from the revolution speed is described.

  Further, in Patent Document 5, the revolution speed of the rolling elements provided with contact angles in opposite directions is changed depending on the direction and magnitude of the load, and the outer ring that is a stationary side race ring is rotated. The structure which calculates | requires one or both of the radial load and axial load which act between the hubs which are a side track ring is described.

  In addition, although not disclosed, for example, in Japanese Patent Application No. 2005-147642, the displacement between the two race rings is measured by an encoder supported on the rotation side race ring and a sensor supported on the stationary side race ring. From this displacement, a structure for obtaining a load applied between these two races is disclosed. In the load measuring apparatus according to the prior invention, an encoder in which the characteristics of the detected surface are alternately changed in the circumferential direction is supported concentrically with the rotation-side raceway on a part of the rotation-side raceway. The sensor is supported by a non-rotating portion such as the stationary-side track ring with the detection unit facing the detection surface, and changes its output signal in response to a change in the characteristics of the detection surface. Let A computing unit calculates a load acting between the two race rings based on the output signal of the sensor. For this purpose, the pitch or phase at which the characteristics of the surface to be detected change in the circumferential direction is continuously changed according to the acting direction of the load to be detected, and the computing unit outputs the output signal of the sensor. It has a function of calculating the load based on a pattern in which changes.

  FIG. 11 shows an example of a structure according to the invention disclosed in Japanese Patent Application No. 2005-147642. The structure according to the prior invention is a rotating side track that rotates together with the wheel while supporting and fixing (bonding and fixing) the wheel to the inner diameter side of the outer ring 1 that is a stationary side ring that does not rotate while being supported by the suspension device. A hub 2 that is a ring is rotatably supported via a plurality of rolling elements 3 and 3. The encoder 4 is externally fitted and fixed to the intermediate portion of the hub 2, and the sensor unit 5 is provided between the rolling elements 3 and 3 arranged in a double row at the axial intermediate portion of the outer ring 1. A mounting hole 6 formed in the outer ring 1 is provided so as to be inserted from the radially outer side of the outer ring 1 to the inner side. A pair of sensors 7a and 7b are provided at the tip of the sensor unit 5 protruding from the inner peripheral surface of the outer ring 1 in a state of being separated in the axial direction of the outer ring 1 (left and right direction in FIG. 11). Yes. And the detection part of both these sensors 7a and 7b is made to adjoin and oppose the outer peripheral surface of the said encoder 4 which is a to-be-detected surface. In addition, it is appropriate to incorporate a magnetic detection element such as a Hall IC, a Hall element, an MR element, or a GMR element in the detection unit of both the sensors 7a and 7b.

  The encoder 4 is formed by laminating a support plate 8 and a permanent magnet 9 in the thickness direction of the permanent magnet 9 (vertical direction in FIG. 11). That is, the support plate 8 is formed by bending a magnetic metal plate such as a mild steel plate, and the axial end edges of the fitting tube portion 10 on the inner diameter side and the support tube portion 11 on the outer diameter side that are concentric with each other. Are connected by a continuous portion 12, and the whole is formed in an annular shape with a crank-shaped cross section. The permanent magnet 9 is supported and fixed over the entire circumference by baking, bonding or the like on the outer peripheral surface of the support cylinder portion 11 of the support plate 8. Further, the encoder 4 is supported and fixed to the outer peripheral surface of the intermediate portion of the hub 2 by fitting the fitting cylinder portion 10 to the intermediate portion of the hub 2 by interference fitting.

  Further, on the outer peripheral surface of the permanent magnet 9, which is the detection surface of the encoder 4, a portion magnetized in the N pole and a portion magnetized in the S pole are alternately arranged at equal intervals in the circumferential direction. It is arranged. The boundary between the part magnetized in the N pole and the part magnetized in the S pole is inclined by the same angle with respect to the axial direction of the encoder 4, and the inclination direction with respect to the axial direction of the encoder 4 is The axial directions are opposite to each other at the intermediate portion. Therefore, the portion magnetized in the N pole and the portion magnetized in the S pole have a “<” shape with the axially middle portion protruding (or recessed) most in the circumferential direction.

  Further, the positions where the detection portions of both the sensors 7 a and 7 b face the outer peripheral surface of the permanent magnet 9 are the same with respect to the circumferential direction of the encoder 4. In other words, the detection parts of both the sensors 7 a and 7 b are arranged on the same virtual plane including the central axis of the outer ring 1. Further, in the state where the axial load is not applied between the outer ring 1 and the hub 2, the axial direction intermediate portion between the portion magnetized in the N pole and the portion magnetized in the S pole is related to the circumferential direction. The installation position of each member 4, 7 a, 7 b is regulated so that the most protruding part (the part where the tilt direction of the boundary changes) is exactly at the center position between the detection parts of the sensors 7 a, 7 b. is doing. In this way, by making the portion where the inclination direction of the boundary changes in the center position, errors due to temperature difference between the inner and outer rings and deformation due to thermal expansion (even if no displacement occurs, the temperature difference between the inner and outer rings The so-called offset, which causes a phase difference, can be kept small.

  In the case of the structure shown in FIG. 11 described above, the encoder 4 is externally fitted to the intermediate portion of the outer peripheral surface of the hub 2 and the sensor unit 5 is inserted into the mounting hole 6 formed in the intermediate portion of the outer ring 1. The invention disclosed in Japanese Patent Application No. 2005-147642 can also be implemented with the structure shown in FIG. That is, the fitting cylinder portion 10a formed at the base end portion of the support plate 8a constituting the encoder 4a is fitted and fixed to the inner end portion of the hub 2 by an interference fit, and is attached to the opening end portion of the outer ring 1. The sensor unit 5a is held and fixed to the cover 13. Then, the detection portions of the pair of sensors 7a and 7b constituting the sensor unit 5a are brought close to and opposed to the outer peripheral surface of the permanent magnet 9 constituting the encoder 4a.

  In any structure, in the case of the load measuring device of the prior invention, 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 7a and 7b change is shifted. That is, in the neutral state in which an axial load is not acting between the outer ring 1 and the hub 2 and the outer ring 1 and the hub 2 are not relatively displaced, the detection parts of the sensors 7a and 7b are It is opposed to the solid lines a and b in FIG. Therefore, the phases of the output signals of the two sensors 7a and 7b coincide as shown in FIG.

  On the other hand, when the downward axial load acts on the hub 2 to which the encoder 4 (4a) is fixed in FIG. 13A (the outer ring 1 and the hub 2 are relatively displaced in the axial direction). The detectors of both the sensors 7a and 7b are opposed to the broken lines B and B in FIG. 13A, 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 7a and 7b are shifted as shown in FIG. Further, when an upward axial load is applied to the hub 2 to which the encoder 4 (4a) is fixed as shown in FIG. 13A, the detecting portions of the sensors 7a and 7b are shown in FIG. The shifts in the axial direction from the chain lines c, i.e., 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 7a and 7b are shifted as shown in FIG.

  As described above, in the case of the load measuring device of the previous invention, the phases of the output signals of the sensors 7a and 7b are shifted in a direction corresponding to the direction of the axial load applied between the outer ring 1 and the hub 2. In addition, the degree to which the phase of the output signals of both the sensors 7a and 7b is shifted by this axial load (displacement amount) increases as the axial load increases. Therefore, in the case of the load measuring device according to the above 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 7a and 7b, and the direction and magnitude of the shift, if any. The direction and magnitude of the axial load acting between the hub 2 can be obtained.

  11 to 12, the permanent magnet 9 constituting the encoder 4 (4 a) has a cylindrical shape with the outer peripheral surface as a detected surface, and between the outer ring 1 and the hub 2 constituting the wheel bearing rolling bearing unit. FIG. 2 shows a structure for obtaining the relative displacement in the axial direction and the axial load applied between the outer ring 1 and the hub 2. On the other hand, the permanent magnet constituting the encoder has a ring shape, and the side surface in the axial direction of the permanent magnet is a detected surface, and a pair of sensors are separated from each other in the radial direction among the detected surfaces. It is also possible to adopt a structure that is close to and opposed to the location. When such a structure is adopted, the relative displacement in the radial direction and further the radial load can be obtained based on the phase shift existing between the detection signals of the two sensors.

  Regardless of the structure of the load measuring device according to the previous invention, the sufficiently high density of magnetic flux reaching each sensor ensures the reliability of the load measurement acting between the rotating member and the stationary member. It is important to do. On the other hand, when implementing a device for measuring the load applied to the wheel-supporting rolling bearing unit, the installation space for the encoder including the permanent magnet is limited, and the width of the detected surface of the permanent magnet is too large. Can not. In order to ensure the reliability, the width dimension is limited, and even if each sensor faces the width direction end of the detection surface of the permanent magnet, It is necessary to make the density of the magnetic flux reaching to sufficiently high. This point will be described with reference to FIG.

In the case of an encoder including a permanent magnet, which has been conventionally known, including the structure of the prior invention disclosed in the aforementioned Japanese Patent Application No. 2005-147642, as shown in the lower part of FIG. The thickness dimension was uniform in the width direction of the detection surface. On the other hand, as shown in the upper part of FIG. 14, the density of the magnetic flux that exits from the N pole existing on the detected surface of the permanent magnet 9 and enters the S pole is a stable region that exists in the intermediate portion in the width direction of the detected surface. However, at both ends in the width direction, it decreases rapidly toward the edge. When the width W _{9 of the} surface to be detected of the permanent magnet 9 is reduced and the width w of the stable region is reduced accordingly, when the displacement to be detected increases, the detection unit of any sensor However, the density of the magnetic flux that protrudes from the stable region and reaches the detection part of the sensor may be extremely reduced. In such a case, there is a possibility that the sensor does not output a sufficiently large signal, and the displacement due to this signal and further the measurement of the load cannot be performed.

  In order to prevent a decrease in measurement reliability due to such a cause, a permanent magnet having a high magnetic strength such as a rare earth magnet is used as the permanent magnet constituting the encoder, or the thickness dimension of the permanent magnet is increased. Thus, it is conceivable to increase the overall density of the magnetic flux entering and exiting the surface of the permanent magnet to be detected. However, in the case of such countermeasures, not only the cost is increased, but the magnetic flux density in the stable region portion in the intermediate portion in the width direction of the detection surface becomes excessively high, so that the threshold value for detection signal processing of the sensor is set. It may cause problems such as difficulty.

JP 2001-21577 A Japanese Patent Laid-Open No. 3-209016 Japanese Patent Laid-Open No. 2004-3918 Japanese Patent Publication No.62-3365 JP 2005-31063 A

  In view of the circumstances as described above, the present invention can sufficiently increase the density of magnetic flux entering and exiting the detected surface portion of the encoder including the permanent magnet in the entire width direction of the detected surface, and at a low cost. The present invention was invented to realize an inexpensive structure capable of measuring the behavior of the encoder with a sensor with high reliability.

The state quantity measuring device of the present invention includes an encoder, a sensor, and a calculator.
Of these, the encoder is supported by a part of the rotating member and rotates together with the rotating member. The encoder is concentric with the rotation center of the rotating member and has a direction perpendicular to the rotating direction of the rotating member as its width direction. A surface to be detected is provided. The detected surface includes a permanent magnet in which S poles and N poles are alternately arranged.
The sensor is supported by a stationary member in a state where the detection portion is opposed to the detection surface of the encoder in the thickness direction of the encoder.
The computing unit has a function of obtaining a state quantity relatively changing between the stationary member and the rotating member based on an output signal of the sensor.
Furthermore, in the state quantity measuring apparatus of the present invention, the thickness dimension of the permanent magnet at the widthwise end of the detected surface is set to the thickness of the permanent magnet at the widthwise central portion of the detected surface. It is larger than the size.

  In the case of the state quantity measuring device of the present invention configured as described above, the thickness dimension of the permanent magnet is thick at the end in the width direction of the detection surface. The end of the detected surface in the width direction tends to have a lower magnetic flux density because there is no permanent magnet beyond it. On the other hand, when the thickness dimension of the permanent magnet is increased, the magnetic flux density of the portion tends to increase. As described above, the width direction end of the surface to be detected tends to increase the magnetic flux density due to the large thickness dimension, instead of decreasing the magnetic flux density in relation to the spread in the surface direction. The change in magnetic flux density due to these two causes cancels each other, and the magnetic flux density at the end portion in the width direction of the detected surface can be suppressed from being lower than the magnetic flux density at the intermediate portion in the width direction. As a result, according to the present invention, the density of the magnetic flux entering and exiting the detected surface portion of the encoder including the permanent magnet can be increased sufficiently and at low cost over the entire width direction of the detected surface. It is possible to realize an inexpensive structure that can measure the behavior of the rotating member that supports the plate with high reliability.

When implementing this invention, Preferably, as described in claim 2, the direction of the boundary between the south pole and the north pole adjacent in the circumferential direction is inclined with respect to the width direction. Then, the calculator is provided with a function for obtaining the relative displacement between the rotating member and the stationary member.
In the case of such a structure, it is configured on the assumption that the detection portion of the sensor and the detection surface of the permanent magnet constituting the encoder are displaced in the width direction of the detection surface. Therefore, in order to ensure the detectable range of the relative displacement without increasing the width dimension of the detected surface, it is necessary to ensure the magnetic flux density at the end in the width direction of the detected surface. Great importance. In other words, the effect obtained by applying the present invention is great.

When implementing the present invention, the structure for increasing the thickness of the permanent magnet at the end in the width direction of the surface to be detected is not particularly limited. For example, as described in claims 3 to 4, an encoder From the viewpoint of increasing the density of the magnetic flux entering and exiting from the detection surface, it is preferable to employ a structure in which a support plate made of a magnetic metal plate and a permanent magnet are laminated in the thickness direction of the permanent magnet. .
And in the case of the structure described in Claim 3, let the cross-sectional shape of the to-be-detected surface of the said permanent magnet be a straight line. On the other hand, the direction in which the distance from the detected surface is greater in the portion of the support plate where the end portion in the width direction of the permanent magnet is to be joined than in the portion where the center portion in the width direction is to be joined. Indent.
On the other hand, in the case of the structure described in claim 4, the cross-sectional shape of the portion of the support plate to which the permanent magnet is to be joined is a straight line. On the other hand, compared with the width direction end of the detected surface of the permanent magnet in the width direction center, the distance from the portion of the support plate to which the permanent magnet should be joined increases. Make it protrude.

Preferably, when carrying out the present invention, preferably, as described in claim 5, the rotating member is a rotating bearing ring that constitutes a rolling bearing unit and rotates during use, and the stationary member is the rolling bearing unit. The stationary side bearing ring that does not rotate even during use or a member that supports and fixes the stationary side bearing ring. Then, based on the relative displacement between the stationary-side raceway and the rotation-side raceway, the arithmetic unit is provided with a function for obtaining a load acting between the two raceways.
If such a configuration is adopted, the load applied to the rolling bearing unit portion supporting various rotating members is measured, for example, control for ensuring the running stability of an automobile, or appropriateness of various machine tools and various industrial machine devices. A signal necessary for performing control for ensuring a proper operation state can be obtained.

  FIG. 1 shows a first embodiment of the present invention corresponding to claims 1 to 3. The feature of this embodiment is that the density of magnetic flux entering and exiting from the outer peripheral surface of the permanent magnet 15 which is the detected surface of the permanent magnet 15 constituting the encoder 14 is made uniform over the entire width of the outer peripheral surface. It is in the structure to do. Regarding the structure and operation for determining the relative displacement between a pair of bearing rings constituting the rolling bearing unit by incorporating the encoder 14, and further, the load acting between the two bearing rings. This is the same as the case of the structure according to the prior invention shown in FIG. Therefore, the illustration and description relating to the same parts as those of the structure according to the present invention will be omitted or simplified, and the following description will focus on the characteristic parts of the present embodiment.

  In this embodiment, the encoder 14 is formed by laminating a support plate 16 and the permanent magnet 15 in the thickness direction of the permanent magnet 15. The support plate 16 is formed by bending a magnetic metal plate such as a mild steel plate, and the end edges in the axial direction of the fitting cylinder portion 17 on the inner diameter side and the support cylinder portion 18 on the outer diameter side that are concentric with each other are continuous. They are connected by a portion 19 and are formed in an annular shape with a crank-shaped cross section. The support cylinder 18 is inclined by an angle θ in a direction in which a cylindrical surface portion 20 having a linear cross-sectional shape is formed at an axially intermediate portion, and an outer diameter dimension is reduced toward the both axial end portions as the distance from the cylindrical surface portion 20 decreases. The partial conical cylindrical surface-like inclined surface portions 21 and 21 each have a substantially trapezoidal cross section. The permanent magnet 15 is supported and fixed over the entire circumference by baking, bonding, or the like on the outer peripheral surface of the support cylinder portion 18 of the support plate 16.

In this way, the shape of the inner peripheral surface of the permanent magnet 15 supported and fixed on the outer peripheral surface of the support cylinder portion 18 is a shape commensurate with the outer peripheral surface shape of the support cylinder portion 18 (inverted irregularities). On the other hand, the outer peripheral surface shape of the permanent magnet 15 is a cylindrical surface whose cross-sectional shape is linear. Therefore, the thickness of the permanent magnet 15, whereas a constant value T ₂₀ at the periphery portion of the cylindrical surface portion 20, the peripheral portion of the both inclined surface portions 21 and 21, toward the both widthwise end edges The width gradually increases and reaches a maximum value T _MAX (> T ₂₀ ) at both edges in the width direction. The permanent magnet 15 is magnetized in the same pattern as that of the structure of the prior invention shown in FIGS. 11 to 14 and the S and N poles are alternately and equally spaced on the outer peripheral surface. The boundary between the S pole and the N pole adjacent in the circumferential direction has a “<” shape with the center portion in the width direction protruding most circumferentially.

  When the state quantity measuring apparatus including the encoder 14 of the present embodiment having such a configuration is configured, the fitting cylinder portion 17 is externally fitted to the intermediate portion of the hub 2 (see FIG. 11) by an interference fit. By doing so, it is supported and fixed to the outer peripheral surface of the intermediate part of the hub 2. Then, the detection portions of the pair of sensors 7a and 7b (see FIG. 11) incorporated in the sensor unit 5 supported on the outer ring 1 side are positioned at two positions on the outer peripheral surface of the permanent magnet 15 that are separated in the axial direction. Proximity to face.

  The thickness dimension of the permanent magnet 15 constituting the encoder 14 is thicker at both end portions in the axial direction of the encoder 14 which are width direction end portions of the detected surface. At the end in the width direction of the surface to be detected, the permanent magnet 15 does not exist any further, so the magnetic flux density tends to be low. On the other hand, when the thickness dimension of the permanent magnet 15 is increased, the magnetic flux density of the portion tends to increase. In this way, the width direction end of the detected surface has a thickness dimension instead of a decrease in magnetic flux density due to the relationship with the spread in the surface direction (there is no permanent magnet further outward in the width direction). Larger magnetic flux density tends to increase. The change in magnetic flux density due to these two causes cancels each other, and the magnetic flux density at both axial ends of the permanent magnet 15 can be suppressed from being lower than the magnetic flux density at the axial intermediate portion.

  That is, in the case of the encoder 14 of the present embodiment, the density of magnetic flux entering and exiting from the outer peripheral surface of the permanent magnet 15 is equal to the entire width of the permanent magnet 15 as shown in the diagram in the upper part of FIG. Almost uniform. The density of the magnetic flux entering and exiting from the outer peripheral surface of the permanent magnet 15 starts to decrease from a position outside the axial end edge of the permanent magnet 15. Therefore, as long as the two sensors 7a and 7b are actually opposed to the outer peripheral surface of the permanent magnet 15, the density of the magnetic flux reaching the detection portions of both the sensors 7a and 7b can be sufficiently increased. In this embodiment, the support cylinder 18 has a trapezoidal cross section, and the permanent magnet 15 is attached to the outer peripheral surface of the support cylinder 18 by plastic working such as pressing or rolling. Each can be easily done. As a result, according to the structure of the present embodiment, the density of the magnetic flux entering and exiting the detected surface portion of the encoder 14 including the permanent magnet 15 can be sufficiently reduced at a low cost over the entire width direction of the detected surface. Can be high. An inexpensive structure that can measure the behavior of the hub 2 supporting the encoder 14 by the sensors 7a and 7b with high reliability can be realized.

  FIG. 2 also shows a second embodiment of the present invention corresponding to claims 1 to 3. In the case of the present embodiment, the cross-sectional shape of the support cylinder portion 18a of the support plate 16a that constitutes the encoder 14a together with the permanent magnet 15a is a mountain shape. That is, the cylindrical surface portion 20 (see FIG. 1) provided at the intermediate portion in the axial direction in the case of the first embodiment is omitted, and the support cylinder portion 18a is formed only by the inclined surface portions 21a and 21a inclined in opposite directions. It is composed. And the outer diameter of this support cylinder part 18a is the largest in the axial direction center part, and it is made small gradually as it goes to an axial direction both ends edge. The shape of the inner peripheral surface of the permanent magnet 15a is a shape commensurate with the shape of the outer peripheral surface of the support cylinder portion 18a, and the outer peripheral surface shape is a simple cylindrical surface. Therefore, the thickness dimension of the permanent magnet 15a is the smallest at the central portion in the axial direction and gradually increases toward the both end edges in the axial direction. The state quantity measuring device is configured by causing the detection portions of the pair of sensors 7a and 7b incorporated in the sensor unit 5 supported on the outer ring 1 side to face each other on the outer peripheral surface of the permanent magnet 15a. The configuration and operation other than the differences in the cross-sectional shapes of the permanent magnet 15a and the support cylinder portion 18a are the same as in the case of the first embodiment described above.

  FIG. 3 also shows a third embodiment of the present invention corresponding to claims 1 to 3. In the case of the present embodiment, the inclined surface portions 21b and 21b formed at both ends in the width direction of the support cylinder portion 18b of the support plate 16b constituting the encoder 14b together with the permanent magnet 15b are convex arc surfaces. The cylindrical surface portion 20a at the intermediate portion in the width direction of the support cylinder portion 18b exists in the tangential direction of both the inclined surface portions 21b and 21b. Except for the fact that the cross-sectional shapes of both the inclined surface portions 21b and 21b are changed from a linear shape to an arc shape, the configuration and operation are the same as those in the first embodiment.

  FIG. 4 also shows a fourth embodiment of the present invention corresponding to claims 1 to 3. In the case of the present embodiment, the entire outer peripheral surface of the support cylinder portion 18c of the support plate 16c constituting the encoder 14c together with the permanent magnet 15c is a convex arc surface. There is no cylindrical surface portion in the intermediate portion in the width direction of the support cylinder portion 18c. The configuration and operation other than the point that the entire outer peripheral surface of the support plate portion 18c is a convex arcuate surface are the same as those in the first embodiment.

  FIG. 5 shows a fifth embodiment of the present invention corresponding to claims 1, 2, and 4. In the case of the present embodiment, the support cylinder portion 18d of the support plate 16d constituting the encoder 14d together with the permanent magnet 15d is formed in a simple cylindrical shape. In other words, the outer peripheral surface of the support cylinder portion 18d is a simple cylindrical surface whose outer diameter does not change in the axial direction. And the inclined convex parts 22 and 22 which protrude in a diameter direction outer side are formed in the width direction both ends of the to-be-detected surface of the said permanent magnet 15d compared with the width direction center part. Specifically, the both end portions in the width direction are inclined by an angle θ to form both inclined convex portions 22 and 22. The outer peripheral surfaces of the both inclined convex portions 22 and 22 are partially conical concave surfaces. In the case of the present embodiment, with this configuration, the thickness dimension of the permanent magnet 15d is made uniform at the center in the width direction of the detected surface, and gradually increases at both edges in the width direction toward the edge. I have to. The configuration and operation other than the differences in the cross-sectional shapes of the permanent magnet 15d and the support cylinder portion 18d are the same as those in the first embodiment.

  FIG. 6 also shows a sixth embodiment of the present invention corresponding to claims 1, 2, and 4. In the case of the present embodiment, the outer peripheral surface of the permanent magnet 15e constituting the encoder 14e together with the support plate 16d is formed in a V-groove shape. That is, the cylindrical surface portion whose outer diameter does not change provided in the intermediate portion in the axial direction in the case of the above-described fifth embodiment is omitted, and the outer peripheral surface of the permanent magnet 15e is composed only of inclined surface portions inclined in opposite directions. is doing. The outer diameter of the permanent magnet 15e is the smallest at the central portion in the axial direction and gradually increases toward the both end edges in the axial direction. The configuration and operation other than the difference in the cross-sectional shape of the permanent magnet 15e are the same as in the case of the fifth embodiment described above.

  FIG. 7 also shows a seventh embodiment of the present invention corresponding to claims 1, 2, and 4. In the case of the present embodiment, the outer peripheral surfaces of the inclined convex portions 22a and 22a formed at both ends in the width direction of the outer peripheral surface of the permanent magnet 15f that constitutes the encoder 14f together with the support plate 16d are concave arcuate curved surfaces. The cylindrical surface portion of the intermediate portion in the width direction of the outer peripheral surface of the permanent magnet 15f exists in the tangential direction of the outer peripheral surfaces of the both inclined convex portions 22a and 22a. The configuration and operation other than the fact that the cross-sectional shape of the outer peripheral surfaces of both inclined convex portions 22a and 22a has changed from a linear shape to an arc shape are the same as in the case of the above-described fifth embodiment.

  FIG. 8 also shows an eighth embodiment of the present invention corresponding to claims 1, 2, and 4. In the case of the present embodiment, the entire outer peripheral surface of the permanent magnet 15g that constitutes the encoder 14g together with the support plate 16d is a concave arc surface. There is no cylindrical surface portion in the intermediate portion in the width direction of the outer peripheral surface of the permanent magnet 15g. Except for the fact that the entire outer peripheral surface of the permanent magnet 15g has a concave arc surface, the configuration and operation are the same as in the case of the fifth embodiment described above.

  FIG. 9 shows Embodiment 9 of the present invention corresponding to claims 1, 2, 3, and 5. In the case of the present embodiment, the first encoder 23 is provided on the outer peripheral surface of the intermediate portion of the hub 2 that is the rotation side raceway, and the inner end {the end that becomes the central portion in the width direction when assembled to the vehicle, The right encoder of FIG. 9 (A)} is fitted on the outer peripheral surface of the second encoder 24 concentrically with the hub 2 by an interference fit. Of these, the first encoder 23 is the characteristic feature of the present invention, that is, the thickness dimension of the permanent magnet 25 is set to the center in the width direction at the width direction end of the outer peripheral surface which is the detected surface of the permanent magnet 25. It has a configuration that is larger than the portion.

  Therefore, in the case of the present embodiment, as the support plate 16 constituting the first encoder 23 together with the permanent magnet 25, the support plate 16 constituting the encoder 14 of the first embodiment shown in FIG. While using the same thing, let the outer peripheral surface of the said permanent magnet 25 be a mere cylindrical surface which does not change a diameter over the axial direction. The first encoder 23 and the encoder 14 of the first embodiment are the same in that the thickness dimension of the permanent magnet 25 is adjusted by the combination of the support plate 16 and the permanent magnet 25. However, in the case of the first encoder 23 incorporated in the present embodiment, the inclination direction of the boundary between the S pole and the N pole arranged alternately at equal intervals on the outer peripheral surface of the permanent magnet 25 in the circumferential direction. Is in a constant direction over the entire width of the outer peripheral surface. On such an outer peripheral surface of the first encoder 23, a detection unit of one sensor 7c provided at the tip of the sensor unit 5b supported on the outer ring 1 which is a stationary side raceway is opposed to and close to the first encoder 23.

  On the other hand, the second encoder 24 is fixedly attached to the inner side surface of the slinger 27 of the combination seal ring 26 that closes the inner peripheral surface of the inner end portion of the outer ring 1 and the outer peripheral surface of the inner end portion of the hub 2. . The second encoder 24 is formed in an annular shape as a whole, and the S pole and the N pole are arranged in the circumferential direction on the inner side which is the detection surface, alternately and at equal intervals. is doing. The boundary between the S pole and the N pole adjacent in the circumferential direction exists in the radial direction of the second encoder 24. The number of S poles and N poles present on the outer peripheral surface of the first encoder 23 is equal to the number of S poles and N poles present on the inner surface of the second encoder 24. On the inner side surface of the second encoder 24 as described above, the detection unit of one sensor 7d provided at the tip of a sensor unit 5c supported by a part of a stationary member such as a knuckle that supports and fixes the outer ring 1 is provided. Are close to each other.

  In the case of this embodiment, an axial load does not act between the outer ring 1 and the hub 2, and both the sensors are used in a neutral state where the outer ring 1 and the hub 2 are not relatively displaced in the axial direction. The detection signals 7c and 7d are changed simultaneously (or with a predetermined time difference). In order to change simultaneously, in the neutral state, the sensor 7d faces the boundary between the S pole and the N pole existing on the inner surface of the second encoder 24, and at the same time, the sensor 7c is moved to the first encoder. The installation positions of the members 7c, 7d, 23, and 24 are regulated so as to face the boundary between the S pole and the N pole existing on the outer peripheral surface of the head 23.

  In the case of this embodiment, the outer ring 1 and the hub 2 are in the axial direction depending on the presence / absence of the phase shift of the detection signals of the sensors 7c and 7d and the direction and magnitude of the shift, if any. Whether or not there is a deviation, the direction and size can be obtained. That is, the phase of the detection signal of the sensor 7d facing the inner surface of the second encoder 24 is constant (no advance or delay) regardless of whether or not there is a deviation in the axial direction. . On the other hand, the phase of the detection signal of the sensor 7c facing the outer peripheral surface of the first encoder 23 is advanced or delayed with the deviation in the axial direction. Accordingly, the detection signal of the sensor 7c facing the outer peripheral surface of the first encoder 23 is synchronized with the timing at which the detection signal of the sensor 7d facing the inner surface of the second encoder 24 changes. The phase and the size of the outer ring 1 and the hub 2 are determined whether or not they are displaced in the axial direction.

  FIG. 10 also shows a tenth embodiment of the present invention corresponding to claims 1, 2, 3, and 5. In the case of the present embodiment, an encoder 28 is externally fitted and fixed concentrically with the hub 2 by an interference fit on the outer peripheral surface of the inner end portion of the hub 2 which is a rotating side race. The encoder 28 is configured to be a feature of the present invention, that is, the thickness dimension of the permanent magnet 25 is made larger at the widthwise end portion of the outer peripheral surface that is the detected surface of the permanent magnet 25 than the widthwise central portion. It has a configuration. For this reason, in the case of the present embodiment, the shape of the tip portion for supporting the permanent magnet 25 as the support plate 16e constituting the encoder 28 together with the permanent magnet 25 is the same as that shown in FIG. The same support plate 16 that constitutes the encoder 14 of Example 1 is used, and the outer peripheral surface of the permanent magnet 25 is a simple cylindrical surface that does not change in diameter in the axial direction.

  In the case of the present embodiment, the axial dimension of the support plate 16e is provided for the purpose of externally fixing the encoder 28 to the inner end portion of the hub 2 so as to protrude inward in the axial direction from the hub 2. Is longer than the support plate 16 constituting the encoder 14 of the first embodiment. The encoder 28 and the encoder 14 of the first embodiment are the same in that the thickness dimension of the permanent magnet 25 is adjusted by the combination of the support plate 16e and the permanent magnet 25. However, in the case of the encoder 28 incorporated in the present embodiment, like the first encoder 23 of the ninth embodiment described above, it is arranged on the outer peripheral surface of the permanent magnet 25 alternately and at equal intervals over the circumferential direction. The inclined direction of the boundary between the S pole and the N pole is made constant over the entire width of the outer peripheral surface.

  In particular, in the case of the present embodiment, the detection portions of the pair of sensors 7e and 7f are placed close to and opposed to the upper and lower ends of the outer peripheral surface of the encoder 28 as described above. That is, the two sensors 7e and 7f are supported and fixed at both upper and lower end portions of the inner peripheral surface of the cover 29 attached to the inner end opening of the outer ring 1 which is a stationary side race ring, and the detecting portions of both the sensors 7e and 7f are supported. Are opposed to both upper and lower end portions of the outer peripheral surface of the encoder 28. 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 28 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 detection signals of the sensors 7e and 7f, in which the detection units are close to and opposed to the upper and lower ends of the outer peripheral surface of the encoder 28, are shifted in the opposite directions with respect to the neutral positions. Therefore, the direction and magnitude of the axial load can be obtained based on the direction and magnitude of the phase shift of the detection signals of both the sensors 7e and 7f.

  The present invention is not limited to the case of measuring the load applied to the wheel support rolling bearing unit as described above. For example, the displacement of the rotation support portion of various machine tools and various industrial machine devices is measured and this rotation is performed. It can also be used when measuring the load applied to the support. In addition, the present invention can be applied not only to measuring displacement and load but also to a structure for detecting the rotational speed. In other words, by applying the present invention to a rotational speed detection device having an encoder made of a permanent magnet, even if an encoder having a small detected surface width is used, the displacement between the encoder and the sensor can be reduced. Regardless, it is possible to ensure a sufficient density of magnetic flux reaching the sensor and to detect the rotational speed with high reliability.

The figure which shows the cross-sectional shape of an encoder, the state of the characteristic change of a to-be-detected surface, and the distribution state of magnetic flux density in the structure of Example 1 of this invention. The expanded sectional view equivalent to the A section of Drawing 11 showing Example 2 of the present invention. The figure similar to FIG. 2 which shows the same Example 3. FIG. The figure similar to FIG. 2 which shows the same Example 4. FIG. The figure similar to FIG. 2 which shows the same Example 5. FIG. The figure similar to FIG. 2 which shows the same Example 6. FIG. The figure similar to FIG. 2 which shows the same Example 7. FIG. The figure similar to FIG. 2 which shows the same Example 8. FIG. The same Example 9 is shown, (A) is sectional drawing which shows the whole structure, (B) is the figure which looked at a part of the to-be-detected surface of the encoder of the right side of (A) from the right side of (A). Sectional drawing which shows the same Example 10. FIG. Sectional drawing which shows the 1st example of the structure which concerns on a prior invention. Sectional drawing which shows the 2nd example. The schematic diagram for demonstrating the reason for which the displacement and axial load of an axial direction are calculated | required by prior invention. The same figure as FIG. 1 for demonstrating the necessity of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer ring 2 Hub 3 Rolling element 4, 4a Encoder 5, 5a, 5b, 5c Sensor unit 6 Mounting hole 7a, 7b, 7c, 7d, 7e, 7f Sensor 8, 8a Support plate 9 Permanent magnet 10, 10a Fitting cylinder part 11 Support cylinder part 12 Continuous part 13 Cover 14, 14a, 14b, 14c, 14d, 14e, 14f, 14g Encoder 15, 15a, 15b, 15c, 15d, 15e, 15f, 15g Permanent magnet 16, 16a, 16b, 16c, 16d, 16e Support plate 17 Fitting cylinder part 18, 18a, 18b, 18c Support cylinder part 19 Continuous part 20, 20a Cylindrical surface part 21, 21a, 21b Inclined surface part 22, 22a Inclined convex part 23 First encoder 24 Second Encoder 25 Permanent magnet 26 Combination seal ring 27 Slinger 28 Encoder 29 Cover

Claims (5)

  A detected surface that is supported by a part of the rotating member and rotates with the rotating member, is concentric with the rotation center of the rotating member and has a direction perpendicular to the rotating direction of the rotating member as its width direction. An encoder comprising a permanent magnet with S poles and N poles alternately arranged on the surface, and a stationary member on the stationary member in a state where the detector is opposed to the detected surface of the encoder in the thickness direction of the encoder. In a state quantity measuring device comprising: a supported sensor; and a computing unit that obtains a state quantity that relatively changes between the stationary member and the rotating member based on an output signal of the sensor. A state quantity measuring device characterized in that the thickness dimension of the permanent magnet at the widthwise end of the detection surface is larger than the thickness dimension of the permanent magnet at the widthwise center of the detection surface.   The boundary direction between the S pole and the N pole adjacent in the circumferential direction is inclined with respect to the width direction, and the computing unit has a function of obtaining a relative displacement between the rotating member and the stationary member. The state quantity measuring device described.   The encoder is formed by laminating a support plate made of a magnetic metal plate and a permanent magnet in the thickness direction of the permanent magnet, and the cross-sectional shape of the detected surface of the permanent magnet is a straight line, and the support plate Among these, the part which should join the width direction edge part of this permanent magnet is dented in the direction where the distance from the said to-be-detected surface becomes large compared with the part which should join the width direction center part. 2. The state quantity measuring device described in any one of the items 2.   The encoder is formed by laminating a support plate made of a magnetic metal plate and a permanent magnet in the thickness direction of the permanent magnet, and the cross-sectional shape of the portion of the support plate to which the permanent magnet is to be joined is It is a straight line, and the end in the width direction of the surface to be detected of the permanent magnet protrudes in a direction in which the distance from the portion to which the permanent magnet is to be joined in the support plate is larger than the center in the width direction. The state quantity measuring device according to any one of claims 1 and 2. The rotating member constitutes a rolling bearing unit and is a rotating bearing ring that rotates during use, and the stationary member constitutes this rolling bearing unit and supports the stationary bearing ring that does not rotate during use or the stationary bearing ring. It is a member to be fixed, and the computing unit has a function of obtaining a load acting between the two race rings based on the relative displacement between the stationary race ring and the rotation side race ring. The state quantity measuring device described in any one of 4.

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