JP4887882B2 - Displacement measuring device and load measuring device of rolling bearing unit - Google Patents

Description

  A displacement measuring device and a load measuring device for a rolling bearing unit according to the present invention, for example, rotatably support a wheel of a vehicle (automobile) relative to a suspension device, and measure the magnitude of a load applied to the wheel, Used to ensure stable operation of vehicles. Alternatively, it is incorporated in a rolling bearing unit for supporting the spindles of various machine tools, is used for measuring the load applied to the spindle and adjusting the feed rate of the tool appropriately.

  For example, a rolling bearing unit is used to rotatably support a vehicle wheel with respect to a suspension device. Moreover, in order to ensure vehicle running stability, vehicle running state stabilizing devices such as an antilock brake system (ABS), a traction control system (TCS), and an electronically controlled vehicle running stabilizer (ESC) are widely used. in use. 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. Furthermore, it is impossible to prevent the running stability of a truck or the like from being deteriorated based on the poor loading state.

  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 1-4 is known as a rolling bearing unit for wheel support 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 thrust direction is detected, and the direction and magnitude of the load applied to the hub are determined based on the detected values of the respective parts.

  Furthermore, 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.

  In the case of the first example of the conventional structure described in Patent Document 1, the load applied to the rolling bearing unit is measured by measuring the displacement in the radial direction between the outer ring and the hub using a displacement sensor. However, since the displacement amount in the radial direction is small, it is necessary to use a highly accurate displacement sensor in order to obtain this load with high accuracy. Since high-precision non-contact sensors are expensive, it is inevitable that the cost of the entire rolling bearing unit with a load measuring device increases.

  In the second example of the conventional structure described in Patent Document 2, it is necessary to provide as many load sensors as the bolts for supporting and fixing the outer ring to the knuckle. For this reason, coupled with the fact that the load sensor itself is expensive, it is inevitable that the cost of the entire load measuring device of the rolling bearing unit is considerably increased. In addition, the structure described in Patent Document 3 is more expensive than the structure described in Patent Document 1 because sensors are installed at four positions in the circumferential direction of the outer ring. Furthermore, the method described in Patent Document 4 needs to reduce the rigidity of a part of the outer ring equivalent member, and it may be difficult to ensure the durability of the outer ring equivalent member.

  In view of such circumstances, Japanese Patent Application No. 2005-147642 discloses an invention for measuring the magnitude of a load applied to a rolling bearing unit based on the phase difference between the output signals of a pair of sensors arranged in the direction in which the load is applied. (Prior invention) is disclosed. 3 to 10 show the structures of two examples of the prior invention disclosed in the above application. As shown in FIGS. 3 and 7, each of the structures according to each of the prior inventions supports and fixes (couples) the wheel to the inner diameter side of the outer ring 1 which is a stationary race ring that does not rotate while being supported by the suspension device. A hub 2 which is a rotating side race ring to be fixed is rotatably supported via a plurality of rolling elements 3 and 3. The encoders 4, 4 a are externally fitted and fixed to the intermediate part of the hub 2, and the sensors 5, 5 a are arranged between the rolling elements 3, 3 arranged in a double row at the axially intermediate part of the outer ring 1. Each pair is provided in a state where the respective detection units are close to and opposed to the outer peripheral surfaces of the encoders 4 and 4a, which are detected surfaces. In addition, it is appropriate to incorporate a magnetic detection element such as a Hall IC, a Hall element, MR, or GMR in the detection portion of the sensors 5 and 5a. In the illustrated example, balls are used as the rolling elements 3 and 3. However, in the case of a rolling bearing unit for automobiles that is heavy in weight, a tapered roller may be used as the rolling element.

  In the case of the structure of the first example of the present invention shown in FIGS. 3 to 6, the encoder 4 is made of a permanent magnet. On the outer peripheral surface of the encoder 4 which is a detection surface, portions magnetized in the N pole and portions magnetized in the S pole are alternately arranged at equal intervals in the circumferential direction. The boundary between the part magnetized in the N pole and the part magnetized in the S pole is inclined by the same angle with respect to the axial direction of the encoder 4, and the inclination direction with respect to the axial direction of the encoder 4 is The axial directions are opposite to each other at the intermediate portion. Therefore, the portion magnetized in the N pole and the portion magnetized in the S pole have a “<” shape with the axially middle portion protruding (or recessed) most in the circumferential direction.

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

  In the case of the 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 at which the output signals of the sensors 5, 5 change is shifted. That is, in the state where an axial load is not acting between the outer ring 1 and the hub 2, the detection parts of the sensors 5 and 5 are above the solid lines a and b in FIG. It faces a portion that is shifted in the axial direction by the same amount from the 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 4 is fixed in FIG. 6A (the outer ring 1 and the hub 2 are relatively displaced in the axial direction), The detection parts of both sensors 5 and 5 are opposed to the parts indicated by broken lines (b) and (b) in FIG. 6A, that is, 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 4 is fixed as shown in FIG. 6A, the detecting portions of both the sensors 5 and 5 are connected to the chain-line hub shown in FIG. , C, that is, the deviation in the axial direction from the most projecting portion opposes different portions in the opposite direction. In this state, the phases of the output signals of the sensors 5 and 5 are shifted as shown in FIG.

  As described above, in the case of the first example of the prior invention, the phases of the output signals of the sensors 5 and 5 are shifted in the direction corresponding to the direction of the axial load applied between the outer ring 1 and the hub 2. Further, the degree to which the phase of the output signals of the sensors 5, 5 is shifted by this axial load (displacement amount) increases as the axial load increases. Therefore, in the case of the first example, based on the presence and absence of the phase shift of the output signals of the sensors 5 and 5 and the direction and magnitude of the shift, between the outer ring 1 and the hub 2. The direction and magnitude of the acting axial load can be determined.

  Next, in the case of the structure of the second example of the prior invention shown in FIGS. 7 to 10, an encoder 4 a made of a magnetic metal plate is externally fitted and fixed to an intermediate portion of the hub 2. Slit-like through holes 6a and 6b and column portions 7a and 7b are alternately arranged at equal intervals in the circumferential direction on the outer peripheral surface of the encoder 4a, which is the detection surface. The through holes 6a and 6b and the column portions 7a and 7b are inclined by the same angle with respect to the axial direction of the encoder 4a, and the inclined direction with respect to the axial direction is bounded by the intermediate portion in the axial direction of the encoder 4a. Are in opposite directions. That is, the encoder 4a is formed with through holes 6a and 6a inclined in the same direction in the predetermined direction with respect to the axial direction in one half of the axial direction, and in the opposite direction to the predetermined direction in the other half of the axial direction. The through holes 6b and 6b inclined by the same angle are formed. 8-9, the slits 6a and 6b, which are slits, are provided in a "C" shape, but the same effect can be obtained by using a "H" -shaped through hole with the tops connected. .

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

  In the case of the second 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), the above-described prior invention. As in the case of the first example, the phase at which the output signals of the sensors 5a and 5a 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 5a and 5a are on the solid lines A and B in FIG. It faces a portion that is displaced from the portion 8 by the same amount in the axial direction. Therefore, the phases of the output signals of the sensors 5a and 5a coincide as shown in FIG.

  On the other hand, when a downward axial load is applied to the hub 2 to which the encoder 4a is fixed in FIG. 10A, the detecting portions of the sensors 5a and 5a are shown in FIG. The broken lines B and B, that is, the portions that are different from each other in the axial direction from the rim portion 8 face each other. In this state, the phases of the output signals of the sensors 5a and 5a 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. 10A, the detecting portions of both the sensors 5a and 5a are connected to the chain line H shown in FIG. , C, that is, the axial displacement from the rim 8 opposes different parts in the opposite direction. In this state, the phases of the output signals of the sensors 5a and 5a are shifted as shown in FIG.

  As described above, in the case of the second example of the prior invention, as in the case of the first example of the previous invention, the phases of the output signals of the sensors 5a and 5a are between the outer ring 1 and the hub 2. It shifts in the direction according to the direction of the axial load applied to. Further, the degree to which the phases of the output signals of the sensors 5a and 5a are shifted by this axial load increases as the axial load increases. Therefore, also in the case of the second example, there is an action between the outer ring 1 and the hub 2 based on the direction and size of the output signal of both the sensors 5a and 5a, if there is a phase shift and if there is a shift. The direction and magnitude of the axial load is determined.

  If the encoder is configured in an annular shape, the side surface in the axial direction of the encoder is a detection surface, and the detection portions of the pair of sensors are opposed to the detection surface in a state shifted in the radial direction, the above It is also possible to determine the displacement in the radial direction between the outer ring 1 and the hub 2 and thus the radial load applied between the outer ring 1 and the hub 2. However, Japanese Patent Application No. 2005-147642 specifically discloses a structure for obtaining both displacement in the axial direction and displacement in the radial direction (both axial load and radial load). It has not been done.

  On the other hand, Japanese Patent Application No. 2004-370407 discloses a specific structure for obtaining both displacement in the axial direction and displacement in the radial direction (both axial load and radial load). Yes. FIG. 11 shows an example of a structure for obtaining the displacement (load) in both directions disclosed in Japanese Patent Application No. 2004-370407. In the case of this structure, a ring-shaped detection surface existing on one side surface in the axial direction of the encoder 9 for obtaining the displacement in the radial direction is inclined in one direction with respect to the radial direction of the encoder 9. Characteristic portions for detection 10 and 10 such as strips, through holes, concave holes, and magnetic poles are provided. In addition, in the axial half of the cylindrical detection surface existing on the outer peripheral surface of the encoder 11 for measuring the displacement in the axial direction {the left half of FIG. Inclined characteristic portions 12 and 12 for detection are provided. On the other hand, the detected characteristic portion parallel to the axial direction of the encoder 11 in the other half portion in the axial direction of the detected surface of the encoder 11 (the right half portion in FIG. 11B). 12a and 12a are provided.

  In the case of such a structure in which encoders 9 and 11 are incorporated, a total of three sensor detection portions are formed on the detection surfaces of both encoders 9 and 11 and the above-described detection characteristic portions 10, 12 and 12 a are formed. Oppose to the part. The direction of the phase shift of the output signals of the remaining two sensors with reference to the moment when the output signals of the sensors facing the detected characteristic portions 12a, 12a change in parallel to the axial direction of the encoder 11. And determine the size. Further, displacements in the axial direction and the radial direction are obtained based on the direction and magnitude of the phase shift.

  According to the structure as shown in FIG. 11 described above, it can be configured to be relatively small, and both the displacement in the axial direction and the displacement in the radial direction can be obtained. However, it may still be difficult to install in a limited space, such as a portion between double row rolling elements constituting a wheel bearing rolling bearing unit of a small automobile. In particular, since the size of this space in the axial direction is often limited, it is difficult to adopt a structure in which the detected surface of the encoder and the sensor are opposed to each other in the axial direction in order to obtain the displacement (load) in the radial direction. There are cases.

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 present invention is a rolling bearing in which not only the displacement (load) in the axial direction but also the displacement (load) in the radial direction is required only by causing the encoder and the sensor to face each other in the radial direction. It is invented to realize a unit displacement measuring device and a load measuring device.

A displacement measuring device and a load measuring device for a rolling bearing unit according to the present invention include a rolling bearing unit and a displacement measuring device or a load measuring device.
Of these, the rolling bearing unit is present on the stationary bearing ring that does not rotate even in use, the rotating bearing ring that rotates in use, and the circumferential surfaces of the stationary bearing ring and the rotating bearing ring that face each other. And a plurality of rolling elements provided between the stationary side track and the rotating side track.
The displacement measuring device or the load measuring device includes an encoder provided concentrically with the rotating raceway at a portion rotating with the rotating raceway, and a detection unit supported by the stationary raceway. A sensor device opposed to the outer peripheral surface, which is a surface to be detected, and a computing unit.
And the said encoder is provided with the 1st, 2nd to-be-detected surface provided in the two places position which mutually deviated from the axial direction among the outer peripheral surfaces. Further, the characteristics of these two detection surfaces change alternately in the circumferential direction and at the same pitch. Furthermore, at least the phase of the characteristic change of the first detected surface is gradually changed in a state different from the second detected surface with respect to the axial direction.
On the other hand, the sensor device includes first to third sensors. Among these, the detection part of the 1st sensor is facing the said 1st to-be-detected surface. Similarly, the detection unit of the second sensor faces the second detection surface in a state where the phase in the circumferential direction of the encoder is matched with the detection unit of the first sensor. Similarly, the detection unit of the third sensor has a phase in the circumferential direction of the encoder different from the detection unit of the first and second sensors by 90 degrees on the first detection surface. Opposite.
And the said arithmetic unit is based on the phase difference which exists between the output signals of said 1st-3rd sensor, and the displacement of the axial direction between the said both bearing rings and the displacement of a radial direction, or Obtain the load applied in the axial direction and the load applied in the radial direction.

In the case of the displacement measuring device and the load measuring device of the rolling bearing unit of the present invention configured as described above, the encoder and the sensor are only opposed to each other in the radial direction, and not only the displacement (load) in the axial direction but also the radial. The displacement (load) in the direction is also obtained.
That is, based on the phase difference between the output signals of the first and second sensors, the displacement (load) in the axial direction can be obtained in the same manner as in the prior invention shown in FIGS. Further, a radial displacement (load) is also obtained based on the phase difference between the output signal of the first sensor and the output signal of the third sensor.
Even in the case of a small rolling bearing unit, the space in the radial direction is relatively easy to secure, so the present invention is, for example, like a portion between double row rolling elements constituting a wheel bearing rolling bearing unit of a small automobile, It is effective as a structure that can be installed in a limited space.
In order to obtain the load acting between the stationary side race ring and the rotation side race ring, it is not always necessary to obtain the relative displacement amount between the stationary side race ring and the rotation side race ring. That is, as described in claim 4, based on the phase difference existing between the output signals of the first to third sensors, the calculator has the stationary side ring and the rotation side ring to It is also possible to have a function of directly calculating the load acting during the period (without going through the process of obtaining the displacement).

In order to carry out the present invention, preferably, as described in claims 2 and 5, a fourth sensor is provided in addition to the first to third sensors. And the detection part of this 4th sensor is made into a 1st to-be-detected surface, and the phase regarding the circumferential direction of an encoder is opposite to said 3rd sensor with respect to the detection part of said 1st, 2nd sensor. It is made to oppose in the state which made it differ by 90 degree | times. Further, the computing unit is configured to determine the axial displacement (load) between the two race rings based on the phase difference existing between the output signals of the first to fourth sensors, and 90 degrees between each other. Two different types of radial displacement (load) are obtained.
According to such a structure, the calculation for obtaining these two types of radial displacements (loads) is simplified, and the displacements in these two directions, and hence the loads applied in these two directions, can be obtained almost in real time. It becomes possible.

Further, when the present invention is implemented, preferably, as described in claims 3 and 6, the rolling bearing unit is configured such that the stationary side race ring is supported and fixed to the suspension device, and the wheel is supported and fixed to the rotation side race ring. A rolling bearing unit for supporting automobile wheels. In the case of the invention described in claim 3, the calculator calculates the relative displacement between the stationary side raceway and the rotation side raceway between the stationary side raceway and the rotation side raceway. Provide a function to calculate the load acting between them.
If configured in this way, the feedforward control prevents slippage between the tire and the road surface, prevents the so-called brake one-side effect where the braking forces of the left and right wheels are extremely different, It is possible to prevent the running stability of the truck or the like from being deteriorated based on the poor loading state.

  FIG. 1 shows a first embodiment of the present invention corresponding to claims 1 and 4. The feature of the present embodiment is that not only the displacement (load) in the axial direction but also the detection portions of the three sensors 13a to 13c are opposed to the outer peripheral surface of the encoder 4a made of a magnetic metal plate in the radial direction. In addition, a radial displacement (load) is also required. That is, by adding one sensor 13c to the structure of the second example of the prior invention shown in FIGS. 7 to 10 described above, the outer ring 1 which is a stationary side race ring and the hub 2 which is a rotation side race ring (FIG. 7). In addition to the displacement (load) in the axial direction, the displacement (load) in the radial direction can be measured. Since the configuration and operation other than the point enabling measurement of the radial displacement (load) are the same as in the case of the second example of the previous invention, the illustration and description regarding the equivalent parts are omitted or simplified. The description will focus on the features of this embodiment. Of the three sensors 13a to 13c, the two sensors 13a and 13b correspond to the pair of sensors 5a and 5a incorporated in the structure of the second example of the prior invention. The structure of the encoder 4a is the same as the structure of the second example of the previous invention. Out of a pair of detected surfaces provided over the entire circumference at two positions in the axial direction of the outer circumferential surface of the encoder 4a, through holes 6a and 6a and column portions 7a and 7a are alternately provided. The portion corresponds to the first detected surface described in the claims, and the portion in which the through holes 6b and 6b and the column portions 7b and 7b are alternately provided corresponds to the second detected surface.

  Among the three sensors 13a to 13c, the detection units of the two sensors 13a and 13b, which correspond to the first and second sensors described in the claims, are included in the outer peripheral surface of the encoder 4a. Thus, the portion is divided into a portion corresponding to the first detected surface and a portion corresponding to the second detected surface, and is opposed to the same position in the circumferential direction of the encoder 4a. As in the case of the second example of the previous invention, the outer ring 1 and the hub 2 (see FIG. 7) are in a neutral state and are positioned between the through holes 6a and 6b formed in the encoder 4a. And the rim | limb part 8 continuing to a perimeter is made to exist in the exact center position between the detection parts of both said sensors 13a and 13b.

  On the other hand, among the three sensors 13a to 13c, the detection part of the remaining one sensor 13c, which corresponds to the third sensor described in the claims, is the outer peripheral surface of the encoder 4a. Thus, it is made to face the portion corresponding to the first detected surface. The position where the detection part of the one sensor 13c faces the outer peripheral surface of the encoder 4a is in a neutral state between the outer ring 1 and the hub 2, and the sensor 13a faces the rotation direction of the encoder 4a. The position is shifted by 90 degrees from the portion of the image. Further, the axial direction of the encoder 4a is the same as the position where the sensor 13a faces.

  According to the structure of the present embodiment configured as described above, based on the phase difference between the output signals of the three sensors 13a to 13c caused by the relative displacement between the outer ring 1 and the hub 2, Not only the displacement (load) in the axial direction but also the displacement (load) in the radial direction is required. With respect to this point, the displacement in each of the x, y, and z directions and the presence / absence of a phase difference between the output signals of the three sensors 13a to 13c will be described. The x, y, and z directions mean the radial direction in the longitudinal direction and the y direction in the axial direction in the case where the present embodiment is applied to a rolling bearing unit for supporting a wheel of an automobile. , And the z direction represents the radial direction with respect to the vertical direction.

(1) When displacement in the x direction occurs (the outer ring 1 and the hub 2 are relatively displaced in the front-rear direction).
In this case, no phase difference is generated between the output signals of the two sensors 13a and 13b provided on the lower side.
On the other hand, between the output signal of the one sensor 13c provided in the horizontal direction and facing the first detection surface, and the output signal of the two sensors 13a and 13b provided on the lower side. A phase difference of a direction and a magnitude corresponding to the displacement (direction and magnitude) in the x direction is generated.
(2) When displacement in the y direction occurs {the outer ring 1 and the hub 2 are relatively displaced in the width direction (axial direction)}. In this case, a phase difference is generated between the output signals of the two sensors 13a and 13b provided on the lower side.
Similarly, a phase difference also occurs between the output signal of one sensor 13c provided in the horizontal direction and the output signal of the sensor 13b provided on the lower side and facing the second detection surface.
On the other hand, there is no phase difference between the output signal of the sensor 13a provided on the lower side and facing the first detection surface and the output signal of one sensor 13c provided in the horizontal direction. .
(3) When displacement in the z direction occurs (the outer ring 1 and the hub 2 are relatively displaced in the vertical direction).
In this case, no phase difference is generated between the output signals of the two sensors 13a and 13b provided on the lower side.
On the other hand, the displacement in the z direction (direction and direction) between the output signal of one sensor 13c provided in the horizontal direction and the output signals of the two sensors 13a and 13b provided on the lower side. A phase difference of a direction and a size according to (size) occurs.

  As apparent from the appearance of the phase difference between the output signals of the sensors 13a to 13c in the state where the displacements in the x, y, and z directions have occurred, Not only the displacement (load) in the direction but also the displacement (load) in the radial direction is required. However, the radial displacement in both the x and z directions cannot be distinguished. Therefore, the structure of the present embodiment is effective for obtaining any one radial displacement in addition to the axial displacement. In other words, if the application or structure is such that the displacement occurs only in one direction of the x direction or the z direction and does not occur in the other direction (a constant value), the above axial, Radial and bi-directional displacement are required.

For example, when the rolling bearing unit is a rolling bearing unit for supporting a driven wheel of an automobile (rear wheel of FF vehicle, FR vehicle, RR vehicle, front wheel of MR vehicle), the load acting during traveling is Except during braking, only the axial load and the radial load in the vertical direction are available, and the radial load in the front-rear direction may be almost negligible. Therefore, assuming that the radial displacement in the x direction is 0, and processing the phase difference between the output signals of the sensors 13a to 13c, the remaining two directions, that is, the y direction which is the width direction of the vehicle, are processed. The displacement in the axial direction and the displacement in the radial direction with respect to the z direction, which is also the vertical direction, can be obtained. That is, the displacement in the y direction is obtained from the phase difference between the output signals of the sensors 13a and 13b, and the displacement in the z direction is obtained from the phase difference between the output signals of the sensors 13a and 13c. Based on the phase difference between the output signals of the sensors 13a to 13c, the method for obtaining the displacement in both the y and z directions is basically the second aspect of the prior invention shown in FIGS. Since it is the same as that of the example, detailed description is abbreviate | omitted.
As described above, if the displacement in both the y and z directions can be obtained, the load applied in both the y and z directions can be obtained. At this time, if necessary, for example, the method described in Japanese Patent Application No. 2004-370407 or Japanese Patent Application No. 2005-110460 is used to reduce the influence of the load on the displacement in the direction other than the action direction. Improve load measurement accuracy. As described above, the load in each direction may be obtained directly without obtaining the displacement in each direction.

  The phase difference between the output signals of the sensors 13b and 13c also changes due to the displacement in the z direction. However, the output signals of both the sensors 13b and 13c change not only by the displacement in the z direction but also by the displacement in the y direction. Since the displacement in the y direction is obtained from the phase difference between the output signals of the sensors 13a and 13b, the influence of the displacement in the y direction is determined from the phase difference between the output signals of the sensors 13b and 13c. Only the displacement in the z direction can also be obtained by a correction operation for removing. However, this is not preferable because the amount of calculation increases and the time required to obtain the displacement in the z direction is not only longer, but errors are more likely to enter.

  FIG. 2 shows a second embodiment of the present invention corresponding to claims 1, 2, 4, and 5. In the case of the present embodiment, in addition to the structure of the first embodiment described above, a sensor 13d as a fourth sensor is provided. And the detection part of this sensor 13d is the same as the detection part of the sensor 13c which is a 3rd sensor, The through-holes 6a and 6a and the pillar parts 7a and 7a which are the 1st to-be-detected surfaces of the encoder 4a are used. It is made to oppose the part provided alternately. The position at which the detection portion of the sensor 13d as the fourth sensor faces the outer peripheral surface of the encoder 4a is in a neutral state between the outer ring 1 and the hub 2 (see FIG. 7), and the rotational direction of the encoder 4a. Is a position shifted 90 degrees from the portion where the sensor 13a is opposed to the side opposite to the sensor 13c as the third sensor. The axial direction of the encoder 4a is the same as the position where the sensors 13a and 13c face each other. In the case of the present embodiment, by adopting such a configuration, the displacement in the three directions x, y, and z is obtained, and further, the load applied in these three directions can be obtained from the displacement in these three directions. .

According to the structure of the present embodiment configured as described above, the axial is based on the phase difference between the output signals of the four sensors 13a to 13d caused by the relative displacement between the outer ring 1 and the hub 2. Not only the displacement (load) in the direction but also the displacement (load) in the radial direction in two directions is obtained. With respect to this point, the displacement in the x, y, and z directions and the presence or absence of a phase difference between the output signals of the four sensors 13a to 13d will be described.
(1) When displacement in the x direction occurs (the outer ring 1 and the hub 2 are relatively displaced in the front-rear direction).
In this case, no phase difference is generated between the output signals of the two sensors 13a and 13b provided on the lower side.
On the other hand, the output signal of the sensor 13b provided on the lower side and facing the second detected surface, and the outputs of the two sensors 13c and 13d provided in the horizontal direction and facing the first detected surface. A phase difference of a direction and a magnitude according to the displacement (direction and magnitude) in the x direction is generated between the signal and the signal.
Further, the output signal of the sensor 13a provided on the lower side and facing the first detection surface, and the output signals of the two sensors 13c and 13d provided in the horizontal direction and facing the first detection surface In the meantime, a phase difference of a direction and a magnitude corresponding to the displacement (direction and magnitude) in the x direction occurs. There is no phase difference between the output signals of the two sensors 13c and 13d provided in the horizontal direction.
(2) When displacement in the y direction occurs {the outer ring 1 and the hub 2 are relatively displaced in the width direction (axial direction)}. In this case, a phase difference is generated between the output signals of the two sensors 13a and 13b provided on the lower side.
Similarly, there is also a phase difference between the output signals of the two sensors 13c and 13d provided in the horizontal direction and the output signal of the sensor 13b provided on the lower side and facing the second detection surface. appear.
On the other hand, the output signal of the sensor 13a provided on the lower side and facing the first detected surface, and the two sensors 13c and 13d provided in the horizontal direction and facing the first detected surface. There is no phase difference between the output signals of the two.
Further, no phase difference is generated between the output signals of the two sensors 13c and 13d provided in the horizontal direction.
(3) When displacement in the z direction occurs (the outer ring 1 and the hub 2 are relatively displaced in the vertical direction).
In this case, no phase difference occurs between the output signals of the two sensors 13a and 13b provided on the lower side.
On the other hand, the output signal of the sensor 13b provided on the lower side and facing the second detected surface, and the two sensors 13c and 13d provided in the horizontal direction and facing the first detected surface. A phase difference occurs between the output signals.
Also, the output signal of the sensor 13a provided on the lower side and facing the first detected surface, and the output signal of the two sensors 13c and 13d provided in the horizontal direction and facing the first detected surface. A phase difference also occurs between them.
Furthermore, a phase difference also occurs between the output signals of the two sensors 13c and 13d provided in the horizontal direction.

In short, the phase between the output signals of the two sensors 13a and 13b provided on the lower side changes only by displacement in the y direction (phase difference occurs) and does not change by displacement in the x and z directions. Therefore, if the presence / absence, direction and size of the phase difference between the output signals of the two sensors 13a and 13b provided on the lower side are measured, the displacement in the y direction can be obtained.
The phase between the output signals of the two sensors 13c and 13d provided in the horizontal direction changes only with displacement in the z direction, and does not change with displacement in the x and y directions. Therefore, the displacement in the z direction can be obtained by measuring the presence, direction, and magnitude of the phase difference between the output signals of the two sensors 13c and 13d provided in the horizontal direction.
Furthermore, the phase between the output signals of the sensors 13a and 13c, which are respectively provided in the lower or horizontal direction and face the first detection surface, varies depending on the displacement in the x direction. It also changes depending on the displacement. However, since the displacement in the z direction is obtained from the phase difference between the output signals of the two sensors 13c and 13d provided in the horizontal direction, the displacement between the output signals of both the sensors 13c and 13d. If the correction calculation that excludes the influence of the displacement in the z direction is performed from the phase difference, only the displacement in the x direction can be obtained. The displacement in the x direction is similarly determined from the phase difference between the output signals of the sensors 13a and 13d, which are provided in the lower and horizontal directions, and are opposed to the first detection surface. It is obtained by performing a correction calculation that excludes the influence of the displacement in the z direction. That is, only the displacement in the x direction can be obtained from the phase difference between the output signals of the sensors 13a and 13c, the phase difference between the output signals of the sensors 13a and 13d, or the average of both phase differences. . As described above, the load in each direction can be obtained from the displacement in each direction, and the load in each direction can be obtained directly without obtaining the displacement in each direction.

  The phase difference between the output signals of the sensors 13b and 13c and the phase difference between the output signals of the sensors 13b and 13d also change due to the displacement in the x direction. It also changes depending on the displacement. Since the displacements in the y and z directions are obtained as described above, these y are calculated from the phase difference between the output signals of the sensors 13b and 13c and the phase difference between the output signals of the sensors 13b and 13d. In addition, only the displacement in the x direction can be obtained by a correction operation for removing the influence of the displacement in the z direction. However, it is not preferable because the calculation amount increases and not only the time required to obtain the displacement in the x direction is increased, but also errors are easily introduced.

  In each of the illustrated examples, an encoder 4a made of a magnetic metal plate having through holes 6a and 6b and column portions 7a and 7b inclined in opposite directions on the first and second detection surfaces was used. The structure is shown. On the other hand, as shown in FIG. 11B, the encoder to be used may be an encoder whose characteristic change boundary is inclined with respect to the axial direction only on the first detected surface portion. it can. Further, the property change of the detected surface of the encoder is not limited to the repetition of the through hole and the column as shown in the figure, but the repetition of the S pole and the N pole as shown in FIGS. Or the repetition of a recessed part and a convex part may be sufficient.

  In the case of a rolling bearing unit for supporting a wheel of an automobile, for example, the rotational speed of the wheel is measured as information for controlling the ABS. In the case of the first embodiment shown in FIG. 1, the three sensors 13a to 13c are used, and in the case of the second embodiment shown in FIG. 2, the four sensors 13a to 13d are used. Is measured. As for the ABS control signal, it is sufficient to input the output signal of any one sensor to the controller for ABS, but the output signals of a plurality of sensors are taken into this controller and compared with each other. It can also be determined whether or not there is any abnormality in the sensor. If there are three or more sensors used to detect the rotational speed of the wheel, even if an abnormality occurs in any of the sensors, a sensor that is considered to be normal in the majority logic is selected, and control is temporarily performed by the sensor. You can also continue.

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

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

1 is a schematic perspective view showing Example 1 of the present invention. The schematic perspective view which shows the same Example 2. FIG. Sectional drawing which shows the 1st example of a prior invention. The perspective view of the encoder built in this 1st example. Similarly development. 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 2nd example of a prior invention. The perspective view of the encoder integrated in this 2nd example. Similarly development. The diagram which shows the output signal of the sensor which changes with the fluctuation | variation of an axial load. The schematic diagram which shows one example of the structure which calculates | requires the displacement of an axial direction and a radial direction based on prior invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a Outer ring 2 Hub 3, 3a Rolling element 4, 4a Encoder 5, 5a Sensor 6a, 6b Through-hole 7a, 7b Pillar part 8 Rim part 9 Encoder 10 Characteristic part for detection 11 Encoder 12, 12a Characteristic part for detection 13a-13d sensor

Claims (6)

A rolling bearing unit and a displacement measuring device;
Of these, the rolling bearing unit is present on a stationary bearing ring that does not rotate even in use, a rotating bearing ring that rotates in use, and circumferential surfaces of the stationary bearing ring and the rotating bearing ring that face each other. A plurality of rolling elements provided between the stationary side track and the rotating side track,
The displacement measuring device includes an encoder provided concentrically with the rotation-side raceway at a portion that rotates together with the rotation-side raceway, and a detection unit supported by the stationary-side raceway as a detected surface of the encoder. It is equipped with a sensor device facing the outer peripheral surface, and a calculator.
The encoder includes first and second detected surfaces provided at two positions on the outer peripheral surface that are axially deviated from each other. The characteristics of these detected surfaces are related to the circumferential direction. Alternately and at the same pitch, and at least the phase of the characteristic change of the first detected surface is gradually changed in a state different from the second detected surface with respect to the axial direction,
The sensor device includes first to third sensors, of which the detection unit of the first sensor faces the first detection surface, and is also the detection unit of the second sensor. Is opposed to the second detection surface in a state where the phase in the circumferential direction of the encoder is matched with the detection unit of the first sensor, and the detection unit of the third sensor is the same as the first detection surface. The phase in the circumferential direction of the encoder is opposed to one detection surface in a state where the phase is different by 90 degrees from the detection units of the first and second sensors,
The arithmetic unit is a rolling bearing unit for obtaining an axial displacement and a radial displacement between the two race rings based on a phase difference existing between output signals of the first to third sensors. Displacement measuring device. In addition to the first to third sensors, a fourth sensor is provided, and the detection unit of the fourth sensor indicates the phase in the circumferential direction of the encoder on the first detected surface, and the first and second sensors. Is opposed to the third sensor on the opposite side to the third sensor in a state of being different by 90 degrees,
Based on the phase difference that exists between the output signals of the first to fourth sensors, the computing unit is based on the axial displacement between the two races and two types of radials that differ from each other by 90 degrees. The displacement measuring device for a rolling bearing unit according to claim 1, wherein a displacement in a direction is obtained.   A rolling bearing unit is a wheel bearing rolling bearing unit for supporting and fixing a stationary side bearing ring to a suspension device, and supporting and fixing a wheel to a rotating side bearing ring. The rolling according to any one of claims 1 to 2, wherein a load acting between the stationary side raceway and the rotation side raceway is calculated based on a relative displacement amount with the rotation side raceway. Displacement measuring device for bearing unit. A rolling bearing unit and a load measuring device;
Of these, the rolling bearing unit is present on a stationary bearing ring that does not rotate even in use, a rotating bearing ring that rotates in use, and circumferential surfaces of the stationary bearing ring and the rotating bearing ring that face each other. A plurality of rolling elements provided between the stationary side track and the rotating side track,
The load measuring device includes an encoder provided concentrically with the rotation-side raceway at a portion rotating together with the rotation-side raceway, and a detection unit supported by the stationary-side raceway as a detected surface of the encoder. It is equipped with a sensor device facing the outer peripheral surface, and a calculator.
The encoder includes first and second detected surfaces provided at two positions on the outer peripheral surface that are axially deviated from each other. The characteristics of these detected surfaces are related to the circumferential direction. Alternately and at the same pitch, and at least the phase of the characteristic change of the first detected surface is gradually changed in a state different from the second detected surface with respect to the axial direction,
The sensor device includes first to third sensors, of which the detection unit of the first sensor faces the first detection surface, and is also the detection unit of the second sensor. Is opposed to the second detection surface in a state where the phase in the circumferential direction of the encoder is matched with the detection unit of the first sensor, and the detection unit of the third sensor is the same as the first detection surface. The phase in the circumferential direction of the encoder is opposed to one detection surface in a state where the phase is different by 90 degrees from the detection units of the first and second sensors,
The computing unit calculates a load applied in the axial direction and a load applied in the radial direction between the two race rings based on a phase difference existing between the output signals of the first to third sensors. Bearing unit load measuring device. In addition to the first to third sensors, a fourth sensor is provided, and the detection unit of the fourth sensor indicates the phase in the circumferential direction of the encoder on the first detected surface, and the first and second sensors. Is opposed to the third sensor on the opposite side to the third sensor in a state of being different by 90 degrees,
Based on the phase difference that exists between the output signals of the first to fourth sensors, the computing unit includes a load applied in the axial direction between the two races and two types that differ from each other by 90 degrees. The load measuring device for a rolling bearing unit according to claim 4, wherein a load applied in a radial direction is obtained.   6. The rolling bearing unit according to claim 4, wherein the rolling bearing unit is a rolling bearing unit for supporting a vehicle wheel, wherein the stationary bearing ring is supported and fixed to the suspension device, and the wheel is supported and fixed to the rotating bearing ring. The load measuring device of the rolling bearing unit described in the item.

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