JP2006133045A - Rotation detection device, and rolling bearing unit with load measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform control utilizing an output signal in the more similar state to a real time, by increasing the total number of times of changes of an output signal from a rotation detection sensor without increasing the number of times of a characteristic change of the surface to be detected of an encoder 2. <P>SOLUTION: Each detection part 9, 9 of two rotation detection sensors are arranged on the surface to be detected of the encoder 2 in the shifted state by δ, a quarter of a pitch P of the characteristic change of the surface to be detected in the rotation direction of the encoder 2. Hereby, the total number of times of timings wherein the output signals from both rotation detection sensors are changed is increased, to thereby enable frequent processing based on the changes. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The rotation detection device of the present invention is used for measuring the rotation speed of the wheels of various vehicles or the rotation shafts of various machine tools and industrial machines with high accuracy. Further, the rolling bearing unit with a load measuring device of the present invention uses the above rotation detector to measure the load applied to the wheels of various vehicles or the rotating shafts of various machine tools and industrial machines with high accuracy. To use.

  In order to control the anti-lock brake system (ABS) for ensuring the running stability of the automobile and preventing the uneven wear of the wheels of the railway vehicle, it is necessary to detect the rotational speed of the wheels of the automobile and the railway vehicle. . Moreover, in order to stabilize the operating state of various machine tools and industrial machines, it is necessary to detect the rotational speed of the rotary shafts of these various machine tools and industrial machines. For example, as a wheel rotation speed detection device for detecting the rotation speed of a wheel for use in controlling an ABS or a traction control device (TCS) for stabilizing the running state of a car, Patent Documents 1, 2, etc. Structures described in many publications are known.

  Conventionally known wheel rotation speed detection devices described in Patent Documents 1 and 2 support and fix an encoder on a hub that is a rotating member that rotates together with the wheel. The characteristics of the detected surface of the encoder provided concentrically with the center of rotation of the hub are changed alternately at equal intervals over the circumferential direction. And the detection part of the rotation detection sensor which was installed in the state adjacent to the said hubs, such as an outer ring or a knuckle, and was supported by a part of the stationary member which does not rotate is adjoined and faced to this to-be-detected surface. When the wheel rotates, the output signal of the rotation detection sensor changes. The frequency of change of the output signal is proportional to the rotational speed of the wheel, and the period of change is also inversely proportional to the rotational speed. Therefore, the rotational speed of the wheel can be obtained based on this frequency or period. The structure for detecting the rotational speed of the rotary shafts of the various machine tools and industrial machines is basically the same.

  Further, in order to further improve the running stability of the automobile, it is required to measure the load (one or both of the radial load and the axial load) applied to each wheel of the automobile in order to perform more advanced control. . Conventionally, structures described in Patent Documents 3 to 6 are known as structures for measuring such a load. Each of the load measuring devices described in Patent Documents 3 to 6 applies a load applied to the rolling bearing that supports the wheel by a displacement sensor, by a load sensor, or by a frequency of vibration of a portion that holds the rolling bearing. Measure.

  In the case of the load measuring apparatus described in Patent Documents 3 to 6 as described above, the cost increases due to the provision of the displacement sensor or the load sensor, or the load sensor is sandwiched in the portion holding the rolling bearing. Alternatively, since the low-rigidity portion is provided, the rigidity or durability of the wheel support portion may be reduced. In view of such circumstances, Japanese Patent Application No. 2004-279155 describes this rolling bearing on the basis of the change pattern of the output signal of the sensor that changes with the rotation of the encoder mounted on the hub constituting the rolling bearing unit. A structure for obtaining the direction and magnitude of the load applied to the unit is described. Since it is effective to implement the present invention in combination with such a prior invention, two examples of the structure according to the prior invention will be described with reference to FIGS. Since the configuration and operation of the wheel bearing rolling bearing unit incorporating the load measuring device has been widely known, detailed description thereof will be omitted.

  First, in the case of the first example of the prior invention shown in FIGS. 11 to 14, an encoder 2 made of a permanent magnet is provided at an intermediate portion of the hub 1, which is a rotating raceway, which rotates together with the wheel while the wheel is supported and fixed. The outer fitting is fixed. N poles and S poles are alternately arranged at equal intervals in the circumferential direction on the outer peripheral surface of the encoder 2 that is the detection surface. The boundary between the N pole portion and the S pole portion is inclined by the same angle with respect to the axial direction of the encoder 2, and the inclined directions with respect to the axial direction are opposite to each other with respect to the intermediate portion in the axial direction of the encoder 2. It has become. 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.

  On the other hand, a pair of rotation detection sensors 5, 5 are installed in a portion between the rolling elements 4, 4 arranged in a double row at the axially intermediate portion of the outer ring 3, which is a stationary side raceway that does not rotate even in use, The detection portions of the both rotation detection sensors 5 and 5 are placed close to and opposed to the outer peripheral surface of the encoder 2. The positions at which the detection portions of the both rotation detection sensors 5 and 5 face the outer peripheral surface of the encoder 2 are the same with respect to the circumferential direction of the encoder 2. In other words, the detection parts of the both rotation detection sensors 5 and 5 are arranged on a virtual straight line parallel to the central axis of the outer ring 3. In the state where an axial load is not applied between the outer ring 3 and the hub 1, the axially intermediate portion between the portion magnetized in the N pole and the portion magnetized in the S pole is the most in the circumferential direction. The installation positions of the members 2, 5, 5 are set so that the protruding part (the part where the inclination direction of the boundary changes) is just at the center position between the detection parts of the both rotation detection sensors 5, 5. It is regulated.

  In the case of the structure of the first example according to the prior invention configured as described above, when an axial load is applied between the outer ring 3 and the hub 1, the phase at which the output signals of the both rotation detection sensors 5, 5 change is changed. Shift. That is, in a state where an axial load is not applied between the outer ring 3 and the hub 1, the detection units of the both rotation detection sensors 5 and 5 are on the solid lines A and B in FIG. A portion shifted by the same amount in the axial direction from the most protruding portion is scanned. Therefore, the phases of the output signals of the both rotation detection sensors 5 and 5 coincide as shown in FIG. On the other hand, when a downward axial load is applied to the hub 1 to which the encoder 2 is fixed in FIG. 14A, the detection units of the both rotation detection sensors 5 and 5 are shown in FIG. A) Scan the broken lines B and B, that is, the portions where the deviations in the axial direction from the most protruding portion are different from each other. In this state, the phases of the output signals of the both rotation detection sensors 5 and 5 are shifted as shown in FIG. Further, when an upward axial load is applied to the hub 1 to which the encoder 2 is fixed as shown in FIG. 14A, the detection portions of the both rotation detection sensors 5 and 5 are shown in FIG. On the chain line c, c, that is, the part where the deviation in the axial direction from the most projecting part is different is scanned in the opposite direction. In this state, the phases of the output signals of the both rotation detection sensors 5 and 5 are shifted as shown in FIG.

  As described above, in the case of the first example according to the invention, the phase of the output signals of the both rotation detection sensors 5 and 5 is a direction corresponding to the direction of the axial load applied between the outer ring 3 and the hub 1. Sneak away. Further, the degree to which the phase of the output signals of the two-rotation detection sensors 5, 5 is shifted by this axial load increases as the axial load increases. Therefore, in the case of the first example, the outer ring 3 and the hub 1 are determined based on the presence and absence of the phase shift of the output signals of the both rotation detection sensors 5 and 5 and, if there is a shift, the direction and magnitude. The direction and magnitude of the axial load acting during

  Next, in the case of the second example of the structure according to the prior invention shown in FIGS. 15 to 18, an encoder 2 a made of a magnetic metal plate is externally fitted and fixed to an intermediate portion of the hub 1. Slit-shaped 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 2a, which is the detection surface. The pitches of the through holes 6a and 6b adjacent to each other in the circumferential direction or the pitches of the column parts 7a and 7b are equal to each other, but the width of each of the through holes 6a and 6b in the circumferential direction and the column parts 7a and 7b. The widths in the circumferential direction need not be equal. However, it is preferable to make them equal in terms of facilitating signal processing. In particular, in the case of the second example, 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 2a, and the inclination direction with respect to the axial direction is inclined. Are opposite to each other with the intermediate portion in the axial direction of the encoder 2a as a boundary. That is, the encoder 2a of this example forms through holes 6a, 6a inclined in the same direction in the predetermined direction with respect to the axial direction in one half of the axial direction, and is opposite to the predetermined direction in the other half of the axial direction. Through holes 6b and 6b are formed that are inclined in the direction by the same angle.

  On the other hand, a pair of rotation detection sensors 5a and 5a is installed between the rolling elements 4 and 4 arranged in a double row at the axially intermediate portion of the outer ring 3, and the detection portions of the both rotation detection sensors 5a and 5a. Is opposed to the outer peripheral surface of the encoder 2a. The positions at which the detection portions of the both rotation detection sensors 5a and 5a face the outer peripheral surface of the encoder 2a are the same with respect to the circumferential direction of the encoder 2a. 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 3 and the hub 1 is provided with the double rotation detection sensor 5a. The installation positions of the members 2a, 5a, and 5a are restricted so as to exist at the center position between the detection units 5a.

  In the case of this example configured as described above, when an axial load is applied between the outer ring 3 and the hub 1, the output signals of the both rotation detection sensors 5a and 5a are output as in the case of the first example. The changing phase shifts. That is, in a state where an axial load is not applied between the outer ring 3 and the hub 1, the detection portions of the both rotation detection sensors 5a and 5a are on the solid lines A and B in FIG. A portion shifted from the rim portion 8 in the axial direction by the same amount is scanned. Therefore, the phases of the output signals of the both rotation detection sensors 5a and 5a coincide with each other as shown in FIG. On the other hand, when a downward axial load is applied to the hub 1 to which the encoder 2a is fixed in FIG. 18A, the detection units of the both rotation detection sensors 5a and 5a are shown in FIG. A) Scans the broken lines B and B, that is, the portions where the deviations in the axial direction from the rim portion 8 are different from each other. In this state, the phases of the output signals of the both rotation detection sensors 5a and 5a are shifted as shown in FIG. Further, when an upward axial load is applied to the hub 1 to which the encoder 2a is fixed as shown in FIG. 18A, the detection portions of the both rotation detection sensors 5a and 5a are shown in FIG. On the chain line c, c, that is, the part where the deviation in the axial direction from the rim portion 8 is different from each other in the opposite direction is scanned. In this state, the phases of the output signals of the both rotation detection sensors 5a and 5a are shifted as shown in FIG.

  As described above, also in the case of the second example of the structure according to the previous invention, as in the case of the first example described above, the phases of the output signals of the both rotation detection sensors 5a and 5a are It shifts in the direction according to the direction of the axial load applied between the two. Further, the degree to which the phase of the output signals of the two-rotation detection sensors 5a and 5a is shifted by this axial load increases as the axial load increases. Therefore, also in the case of this example, the presence or absence of a phase shift of the output signals of the both rotation detection sensors 5a and 5a, and if there is a shift, between the outer ring 3 and the hub 1 based on the direction and magnitude. The direction and magnitude of the acting axial load can be determined.

  Although illustration is omitted, the technique for obtaining the load applied to the rolling bearing unit based on the pattern in which the output signals of the pair of rotation detection sensors change is not limited to obtaining the axial load, but when obtaining the radial load. It is applicable even if it takes. When determining the radial load, the detected surface of the encoder is the axial side surface. In addition, a pair of encoders are arranged shifted in the radial direction of the detected surface. Further, the boundary where the characteristics of the detected surface change is inclined with respect to the radial direction. Then, the inclination direction with respect to the radial direction is reversed between the inner diameter side and the outer diameter side with respect to the radial center of the detected surface.

  By the way, in order to improve the performance of a device that performs some control according to the output signal of the rotation detection sensor, which changes according to the rotation speed of the rotating member, the number of times the output signal changes during one rotation of the encoder. It is preferable that the total is large. This is not limited to merely obtaining the rotational speed of the rotating member, but as described above, the rolling bearing unit is based on the pattern of the output signals of the rotation detection sensors 5 and 5a that change as the hub 1 rotates. It can also be said in the case of the load measuring device according to the prior invention that obtains the axial load (or radial load) applied to. This is because, as the total number of times that the output signal changes is larger, some control based on the output signal can be performed quickly (closer to real time).

  For example, when ABS or TCS control is performed according to the rotational speed of the hub, it is preferable to use data as close to the moment as possible from the viewpoint of appropriate control. In view of this aspect, obtaining the rotational speed using the frequency of the change in the output signal requires a certain amount of time until the rotational speed is obtained (the time lag increases). It is not preferable. On the other hand, if the rotation speed is obtained using the period of change of the output signal, the time lag can be made much smaller than when the frequency is used. The time lag can be further reduced by using the period of the change and increasing the number of boundaries where the characteristic existing on the detection surface of the encoder changes (number of characteristic changes). The structure similar to that shown in FIGS. 11 to 18 can be considered for the structure for obtaining the load applied to the rolling bearing unit portion based on the output signal of the rotation detection sensor.

  However, there is a limit to increasing the number of boundaries where the characteristics existing on the detected surface change. For example, in the case of the encoder 2 made of a permanent magnet as shown in FIG. 12, it is adjacent in the circumferential direction both from the subdivision surface of the magnetizing yoke constituting the magnetizing device and from the surface of ensuring the magnetization accuracy. Even from the surface where the magnetic flux flowing between the S pole and the N pole reaches the detection unit of the rotation detection sensor located at a certain distance from the detection surface, the boundary of the boundary is not increased unless the encoder diameter is increased. It is difficult to increase the number dramatically (for example, 2 to 3 times). Further, even in the case of the encoder 2a made of a magnetic metal plate as shown in FIG. 16, the durability of the punch for punching and forming the through holes 6a and 6b is ensured, and the through holes 6a adjacent in the circumferential direction are provided. Considering the securing of the strength of the pillars 7a and 7b existing between the 6b and prevention of leakage of the magnetic flux flowing between the detection part of the sensor and the surface to be detected of the encoder 2a, the number of the above boundaries is dramatically increased. It is difficult to make more.

Japanese Patent Laid-Open No. 11-174071 JP 11-183492 A Japanese Patent Publication No.62-3365 Japanese Patent Laid-Open No. 3-209016 JP 2001-21577 A Japanese Patent Laid-Open No. 2004-3918

  In view of the above-described circumstances, the present invention increases this output by increasing the total number of times the output signal of the rotation detection sensor changes without particularly increasing the number of changes in the characteristics of the detected surface of the encoder. The present invention has been invented to realize a rolling bearing unit with a rotation detection device and a load measurement device that can perform control using signals in a state closer to real time.

Of the rotation detecting device and the rolling bearing unit with a load measuring device according to the present invention, the rotation detecting device according to claim 1 includes an encoder and a rotation detecting sensor, like the rotation detecting device widely known in the art. .
Of these, the encoder is supported by the rotating member and rotates together with the rotating member. The characteristics of the detection surface provided concentrically with the rotation center of the rotating member are alternately and over the circumferential direction. The interval is changed.
The rotation detection sensor is installed in a state adjacent to the rotation member and is supported by a part of a stationary member that does not rotate, and the detection unit faces the detection surface.
In particular, in the rotation detection device of the present invention, when n is a natural number of 2 or more (generally n = 2 to 4, n = 2 in consideration of cost and accuracy), the rotation detection sensor described above. N are provided. The phase of each of the n rotation detection sensors that faces the detection surface of the encoder is known in the rotation direction of the encoder with respect to the phase in which the characteristics of the detection surface change. They are shifted from each other by the value.

A rolling bearing unit with a load measuring device according to an eleventh aspect includes 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. And a plurality of rolling elements provided between the stationary side track and the rotating side track.
The load measuring device includes a rotation detection device and a computing unit.
Of these, the rotation detection device is a rotation detection device as described above, and as an encoder, the phase at which the characteristics of the surface to be detected change in the circumferential direction depends on the direction of action of the load to be detected. It incorporates what has been changed continuously.
Further, the computing unit has a function of calculating a load acting between the stationary side raceway and the rotation side raceway based on a pattern in which output signals of n rotation detection sensors change. is there.

  In the case of the rolling bearing unit with the rotation detecting device and the load measuring device of the present invention configured as described above, the n rotation detecting sensors change output signals at different timings, so that some control is performed. The number of cycles in which the output signal changes increases n times. That is, if the controller side watches the timing when the output signal of each rotation detection sensor changes, and obtains the interval (cycle) between the instants when each output signal changes, the rotational speed of the rotating member is further obtained from this interval. In addition, the load applied to the rotating member can be obtained. Of course, when measuring the load, the controller side recognizes which rotation detection sensor is the rotation detection sensor whose output signal is changed at each moment. If it is only used to determine the rotation speed of the rotating member (if the output signal of each rotation detection sensor does not change with the change in load), the controller side It is not necessary to recognize which rotation detection sensor is the rotation detection sensor whose output signal is changed instantaneously. However, in that case, by adopting the structure of claim 2 or claim 3 described below, the change in the output signal of each rotation detection sensor occurs at equal intervals unless the rotation speed of the encoder changes. To.

When carrying out the invention described in claim 1, for example, as described in claim 2, the phase in which each of the detection units of the n rotation detection sensors faces the detection surface of the encoder is determined by the rotation of the encoder. A known value that is shifted in the direction is set to 1 / 2n pitch of the pitch at which the characteristic of the detection surface of the encoder changes.
When such a configuration is adopted, the rotation of the rotating member is performed using both points where the output signal of each rotation detection sensor rises and falls (edge portions of both pulses of the output signal). When obtaining the speed, the timing for obtaining the rotational speed can be increased n times.
Alternatively, as described in claim 3, the known value is set to 1 / n pitch of the pitch at which the characteristics of the detection surface of the encoder change.
When such a configuration is adopted, rotation is performed using one of the points where the output signal of each rotation detection sensor rises and falls (either one of the pulses of the output signal). When obtaining the rotation speed of the member, the timing for obtaining the rotation speed can be increased n times.
In the case of the above description, in a rolling bearing unit equipped with n rotation detection sensors, the rotation direction deviation between the detection unit of each rotation detection sensor and the detected surface of the encoder is 1 / 2n. The pitch or 1 / n pitch is used. On the other hand, with respect to the rolling bearing unit on which m (m> n) rotation detection sensors are mounted, the detection unit of each rotation detection sensor and the detected surface of the encoder for any n of the m rotation detection sensors. The rotation direction deviation can be ½n pitch or 1 / n pitch.
In addition, the rotation direction of the rotating member is discriminated by using the output signals sent out from n rotation detection sensors in a state of being shifted in phase as output signals corresponding to the so-called encoder A phase and B phase. You can also do it.

Further, when carrying out the invention described in claim 1, for example, as described in claim 4, the detection portions of the n rotation detection sensors are arranged at the same position with respect to the rotation direction of the encoder. And the phase in which the characteristic of the to-be-detected surface of this encoder changes is mutually shifted regarding the said rotation direction between the arrangement positions of the detection part of each said rotation detection sensor.
In this case, for example, as described in claim 5, the encoder includes one encoder in which the phase in which the characteristic is changed is shifted from each other between portions in which the positions in the width direction of the detection surface are different from each other.
When such a configuration is employed, the phase can be accurately shifted without particularly rigorously assembling the encoder with respect to the rotating member.
Alternatively, as described in claim 6, n encoders are provided in a state in which the phases in which the characteristics of the detected surface change are shifted from each other with respect to the rotation direction of each encoder.
When such a configuration is adopted, it is necessary to strictly assemble the encoders with respect to the rotating member. However, since each encoder can be reduced in size, the encoders can be easily assembled in a limited space. .

When carrying out the invention described in claim 1, or as described in claim 7, the detection units of the n rotation detection sensors are installed at positions shifted with respect to the rotation direction of the encoder. In this case, the phase at which the characteristic of the encoder changes cannot be deviated as in claims 4 to 6 described above.
According to any one of the structures described in claims 4 and 7, the phase at which each detection unit of the n rotation detection sensors faces the detected surface of the encoder is related to the pitch at which the characteristics of the detected surface change. They can be shifted from each other by 1 / 2n pitch or 1 / n pitch.

When the present invention is carried out, the encoder is made of a permanent magnet as described in claim 8, for example. Then, N poles and S poles are alternately arranged at equal intervals in the circumferential direction on the detection surface of the encoder.
Alternatively, as described in claim 9, the encoder is made of a magnetic metal plate, and through holes and column portions are alternately arranged in the circumferential direction on the detection surface of the encoder. In this case, with respect to the rotation direction of the encoder, the width of the through hole and the width of the column portion do not necessarily have to coincide with each other. However, as described above, when the rotation speed of the rotating member is obtained by using both edge portions of the pulse which is the output signal, the width of the through hole and the width of the column portion may be matched with each other. preferable.

Further, when implementing the present invention, preferably, as described in claim 10, an IC constituting n rotation detection sensors is supported on the tip of a single holder. In this case, for example, the IC holding these rotation detection sensors at predetermined intervals is embedded and supported in a synthetic resin holder in a state in which the direction is regulated.
If comprised in this way, the operation | work which regulates the shift | offset | difference regarding the circumferential direction of the to-be-detected surface of an encoder of the detection part of said n rotation detection sensor to known values, such as 1 / 2n pitch or 1 / n pitch. Can be performed easily and accurately. That is, for example, in the case of an encoder for detecting the rotational speed of an automobile wheel, the pitch at which the characteristics of the detected surface change is about 4 to 8 mm at the center of the detected surface. For this reason, it is troublesome to configure the n rotation detection sensors independently of each other, and to dispose the detection units of these rotation detection sensors with an accurate shift of 1 / 2n pitch or 1 / n pitch. . On the other hand, when the rotation detection sensor manufacturing factory supports the ICs constituting the n rotation detection sensors on the tip of a single holder as described above, the above-described regulation operation can be performed easily and accurately. The

Further, when the rolling bearing unit with a load measuring device according to claim 11 is implemented, for example, as described in claim 12, n is set to 2, and the detection portions of the two rotation detection sensors are arranged in the rotation direction of the encoder. Are arranged at the same position. Then, the direction in which the phase in which the characteristics of the detected surface of the encoder changes changes in the opposite direction to the arrangement direction of the both rotation detection sensors, with the width direction central portion of the detected surface as a boundary. In addition, the phase of the change is shifted from each other by 1/4 pitch or 1/2 pitch on both sides of the central portion in the width direction.
Alternatively, as described in claim 13, n is set to 2, and the detection units of the two rotation detection sensors are arranged at positions shifted by 1/4 pitch or 1/2 pitch with respect to the rotation direction of the encoder. Then, the direction in which the phase at which the characteristic of the detection surface of the encoder changes changes is opposite to the arrangement direction of the both rotation detection sensors, with the central portion in the width direction of the detection surface as a boundary. In addition, the phases of change are made to coincide with each other on both sides of the central portion in the width direction.

When configured in this way, the pattern in which the output signals of the two rotation detection sensors shift is changed according to the magnitude of the load acting in the width direction of the detected surface. Then, the computing unit determines in which direction (the advance direction or the delay direction) the phase of the output signal of which rotation detection sensor is compared with the output signals of other rotation detection sensors (for one pitch). It is calculated how much load is applied in which direction with respect to the width direction of the surface to be detected, depending on the degree of deviation).
The output signals of the two rotation detection sensors are shifted by 1 / 2n pitch or 1 / n pitch even when the load is not applied. Therefore, when this load is applied, the detection signal that is the timing (trigger) for obtaining this load is n times that in the case where the detection portions of the two rotation detection sensors are not shifted. . As a result, the load can be obtained in a state closer to real time.

Moreover, when implementing the rolling bearing unit with a load measuring device according to claim 11, for example, as described in claim 14, for example, the rolling bearing unit is rotatably supported on a suspension device of an automobile. Rolling bearing unit for wheel support. The load calculated by the computing unit is a load applied between the suspension device and the wheel.
If comprised in this way, the load added between each wheel and suspension of a motor vehicle will be calculated | required, and it will be useful for the control for aiming at the running stability ensuring of this motor vehicle.

Further, when the rolling bearing unit with a load measuring device described in claim 14 is implemented, for example, as described in claim 15, the load calculated by the calculator is applied between the suspension device and the wheel. Use radial load. In this case, the detected surface of the tone wheel is the axial side surface of the tone wheel, and the phase of the characteristic change of the detected surface is changed with respect to the radial direction of the detected surface.
Alternatively, as described in claim 16, the load calculated by the calculator is an axial load applied between the suspension device and the wheel. In this case, the detected surface of the tone wheel is the peripheral surface of the tone wheel, and the phase of the characteristic change of the detected surface is changed with respect to the axial direction of the detected surface.
If comprised in this way, the radial load or axial load added between each wheel of a motor vehicle and a suspension apparatus can be calculated | required according to the control to perform.

  1 and 2 show a first embodiment of the present invention corresponding to claims 1, 2, 7, 8, 11, 13, 14, and 16. This embodiment acts between the hub 1 and the outer ring 3 by using a permanent magnet made of a cylindrical encoder 2 fitted and fixed to the hub 1 as shown in FIGS. This is an effective structure to apply when determining the axial load. Therefore, the structure of the encoder 2 is the same as that of the encoder 2 incorporated in the rolling bearing unit with a load measuring device shown in FIGS. That is, the N pole and the S pole are alternately arranged at equal intervals in the circumferential direction on the outer peripheral surface of the encoder 2 that is the detection surface. The boundary between the N pole portion and the S pole portion is inclined by the same angle with respect to the axial direction of the encoder 2, and the inclined directions with respect to the axial direction are opposite to each other with respect to the intermediate portion in the axial direction of the encoder 2. It has become.

  In particular, in the case of the present embodiment, the installation positions of the detection units 9 and 9 of the pair of rotation detection sensors 5 and 5 (see FIG. 11) that are close to and opposed to the outer peripheral surface that is the detection surface of the encoder 2. Are shifted from each other with respect to the rotation direction of the encoder 2 (left-right direction in FIG. 1) by δ. In this way, the amount δ by which the detection units 9 and 9 are shifted is set to ¼ (δ = P / 4) of the pitch P at which the characteristics of the detected surface change. In addition, with no axial load acting between the hub 1 and the outer ring 3 (see FIG. 11), the boundary between the N pole portion and the S pole portion is related to the circumferential direction with respect to the axial direction of the encoder 2. The most projecting (or recessed) portion is present at the center position of both the detection units 9 and 9.

The operation of the present embodiment having the above-described configuration is as follows. In the case of this embodiment, both the points where the output signals of the both rotation detection sensors 5, 5 rise and fall (both edge portions of the pulse which is the output signal) are used. Then, the rotational speed of the hub 1, which is a rotating member, and the axial load are obtained.
First, the case where an axial load does not act between the hub 1 and the outer ring 3 will be described. In this case, the positional relationship between the encoder 2 and the both rotation detection sensors 5 and 5 in the axial direction between the hub 1 and the outer ring 3 is in a neutral state, and the output signals of the both rotation detection sensors 5 and 5 Changes as shown in FIG. Note that the output signal shown in FIG. 14 changes in a sine wave form, whereas the output signal shown in FIG. 2 changes in a rectangular wave form (pulse form). Such a difference in waveform depends only on whether or not a waveform shaping circuit is provided. That is, the rectangular wave output signal shown in FIG. 2 can be obtained by processing the sine wave output signal shown in FIG. 14 by the waveform shaping circuit. Since the waveform shaping circuit is well known, detailed description thereof is omitted.

  Of the output signals of the two-rotation detection sensors 5 and 5 shown in FIG. 2, the portions indicated by arrows are the points where the output signal rises and falls. When only the output signal of one of the rotation detection sensors 5 is viewed, the sum of the rising point and the falling point in one cycle corresponding to one pitch of the characteristic change of the encoder 2 is two points. Only. On the other hand, when the output signals of the both rotation detection sensors 5 and 5 are viewed together, the total of the rising point and the falling point in one cycle is 4 points. That is, in the state where the axial load is not applied, the rising point and the falling point are alternately between the rotation detection sensors 5 and 5 (as long as the rotation speed of the hub 1 is constant). ) Appear at regular intervals. That is, after the output signal of one rotation detection sensor 5 increases (or decreases), the output signal of the other rotation detection sensor 5 decreases (or increases) after a predetermined time (short time) has elapsed. The length of the predetermined time is inversely proportional to the rotational speed of the hub 1. Therefore, the rotational speed of the hub 1 can be obtained based on the predetermined time. In this way, the timing at which the rotational speed of the hub 1 is obtained appears four times during the one period. For this reason, the control performed based on this rotational speed can be performed in a state close to real time.

Next, a procedure for obtaining the axial load when an axial load acts between the hub 1 and the outer ring 3 will be described. When an axial load is applied between the hub 1 and the outer ring 3, the output signals of the both rotation detection sensors 5, 5 are the same as in the first example of the prior invention described with reference to FIGS. Out of phase. That is, the time t ₁ from when the output signal shown in one (upper side) of FIG. 2 drops until the other (lower side) output signal rises, and after the other output signal rises, The time t ₂ until the output signal rises does not match (t ₁ ≠ t ₂ ). Which time t ₁ (t ₂ ) becomes longer depends on the direction in which the axial load acts, and how much difference occurs between these times t ₁ and t ₂ depends on the magnitude of the axial load. It depends on the size. Therefore, if the ratio (t ₁ / t ₂ ) between the times t ₁ and t ₂ is obtained, the acting direction and the magnitude of the axial load can be obtained.

Further, the distance between the point of falling and the point of the rise, as shown by t ₁ ~t ₄ in FIG. 2, there four positions in one cycle corresponding to one pitch of the characteristic change of the encoder 2. The direction and magnitude of the axial load is determined by the ratio between adjacent intervals (t ₁ / t ₂ , t ₂ / t ₃
, T ₃ / t ₄ , t ₄ / t ₁ ). Of course, in order to specify the acting direction of the axial load, an arithmetic unit for calculating the axial load is required to select any ratio (t ₁ / t ₂ , t ₂ / t ₃ , t ₃ / t _4). , T ₄ / t ₁ ), and the action direction is specified accordingly. The above-mentioned t ₁ ~t ₄ becomes negative (the timing of the change in the output signal of both rotation sensor 5,5 is reversed before and after) about, never axial displacement of the encoder 2 becomes significant. As is clear from the above description, according to the present embodiment, even when the axial load is obtained, it appears four times in one period corresponding to one pitch of the characteristic change of the encoder 2. For this reason, the control performed based on the axial load can be performed in a state close to real time.

  Next, a procedure for obtaining the rotational speed of the hub 1 when this axial load is applied will be described. As is apparent from the above description of the procedure for obtaining the axial load, when the axial load is applied, the distance between the rising point and the falling point is not equal according to the axial load. Become. Therefore, as it is, the rotational speed cannot be accurately obtained by the same procedure as that when the axial load is not applied as described above. Therefore, in order to obtain the rotation speed in such a case, the following three procedures (a) to (c) can be considered.

(a) Disregarding the above-mentioned gap (t _{1 to} t ₄ variation) based on the axial load.
The amount by which this interval is shifted based on this axial load (where t _{1 to} t ₄ vary) is about several percent. Therefore, if the accuracy required for the measured value of the rotational speed is about 10%, the rotational speed can be obtained at a level that does not cause any practical problem even if the deviation is ignored.
(b) The rotational speed is obtained based on values obtained by adding adjacent intervals (t ₁ + t ₂ , t ₂ + t ₃ , t ₃ + t ₄ , t ₄ + t ₁ ).
If the rotational speed is obtained in this way, the rotational speed is accurately obtained as long as the width between the S pole and the N pole existing on the detected surface of the encoder 2 in the rotational direction of the encoder 2 is accurate. It is done. In this case, the time for which the observation is continued in order to obtain the rotational speed becomes longer, but the timing for obtaining the rotational speed appears four times in one period corresponding to one pitch of the characteristic change of the encoder 2. That is, if the structure on the controller side is devised, the rotational speed measurement work for two times before and after can be performed at the same time (partially overlapping the processing time).
(c) Correct based on the obtained axial load.
The amount by which this interval deviates based on this axial load (where t _{1 to} t ₄ fluctuate) changes in a proportional or nearly proportional state in accordance with this axial load. Therefore, if the interval t _{1 to} t ₄ is multiplied by a correction coefficient in accordance with the obtained axial load, a more accurate rotational speed can be obtained than in the case (a).
Which of these (a) to (c) is adopted is selected according to the accuracy of the control performed using the obtained rotation speed.

  In carrying out the present invention, the pair of rotation detection sensors 5 and 5 are preferably of the same type (having the same characteristics). However, the same type of rotation detection sensor cannot be used for some reason, and as a result, the output signals of the both rotation detection sensors 5 and 5 (although no geometric phase shift has occurred). ) If an electrical phase shift occurs, this phase shift is corrected. That is, in such a case, the amount of electrical phase deviation is grasped in advance, and the electrical phase deviation is detected on the controller side that has received the output signals of the both rotation detection sensors 5 and 5. After correcting (releasing), the axial load and the rotational speed are obtained.

  In this case, if the phase shift is constant, the correction value is a constant. On the other hand, when this phase shift increases or decreases as the rotational speed changes, it is necessary to change the correction value depending on the rotational speed. Further, the correction of the phase shift as described above may be necessary even when the same type of rotation detection sensor is used. For example, a rectangular wave (pulse wave) that is an output signal of each rotation detection sensor that changes in response to a change in the characteristics of the detection surface of the encoder is not a complete rectangular wave, and this output signal rises. Someone is generated at a point or a point of descent. Such an avalanche is caused by the characteristics of an electrical component incorporated in an electrical circuit attached to the rotation detection sensor, and the magnitude of the avalanche is expressed by a time constant. Even if the time constants are the same, in the normal case, the shape of each of the output signals is different between the point where the output signal rises and the point where it falls. Therefore, even if the time constants of one rotation detection sensor and the other rotation detection sensor are exactly the same, the point that the output signal of one rotation detection sensor rises and the detection signal of the other rotation detection sensor There is a possibility that the phase difference detected from the point at which descents changes depending on the rotation speed. Although the difference due to the difference in the shape of the one is considered to be constant as the time difference, the ratio of the time difference with respect to one pitch of the reference characteristic change, that is, the phase difference changes depending on the time length of one reference pitch. As a result, a phase difference is generated depending on the rotation speed. In such a case, the detected time difference data is corrected, or the calculated phase difference data is corrected depending on the rotation speed.

  FIG. 3 shows a second embodiment of the present invention corresponding to claims 1, 3, 7, 8, 11, 13, 14, and 16. Similarly to the case of the above-described first embodiment, this embodiment also uses a cylindrical magnet 2 made of a permanent magnet and externally fixed to the hub 1 as shown in FIGS. This structure is effective when applied to obtain an axial load acting between the hub 1 and the outer ring 3. In the case of the present embodiment, one of the points where the output signals of the pair of rotation detection sensors 5, 5 (see FIG. 11) rise and fall (any one of the pulses as the output signal). It is assumed that the rotational speed of the hub 1 that is a rotating member and the axial load are obtained using only one edge portion).

  In particular, in the illustrated example, the axial load and the rotational speed are obtained by using only the point where the output signals of the both rotation detection sensors 5 and 5 rise (without using the point where it falls). . Therefore, in the case of the present embodiment, as shown by the solid line and the chain line in FIG. 1 described above, the detection units 9 and 9 of the both rotation detection sensors 5 and 5 are twice as long as the case of the first embodiment. The rotation direction of the encoder 2 is shifted by 2δ, that is, 1/2 of the pitch P (2δ = P / 2) at which the characteristics of the detected surface of the encoder 2 change.

  In the case of this embodiment, the timing for obtaining the axial load and the rotational speed is less (halved) than in the case of Embodiment 1 described above, but this timing is one pitch of the characteristic change of the encoder 2. Appears twice in the corresponding period. The axial loads and the detection points 9 and 9 of the both rotation detection sensors 5 and 5 are not shifted in the rotation direction of the encoder 2 and the output signals of the both rotation detection sensors 5 and 5 rise only. When the rotational speed is obtained, the timing for obtaining these appears only once in one period corresponding to one pitch of the characteristic change of the encoder 2. Therefore, also in the case of the present embodiment, the control performed based on the axial load and the rotation speed by shifting the detection units 9 and 9 of the both rotation detection sensors 5 and 5 in the rotation direction of the encoder 2 is conventionally performed. Or, it can be performed in a state close to real time as compared with the prior invention.

FIG. 4 shows a third embodiment of the present invention corresponding to claims 1, 2, 7, 8, 11, 13, 14, and 16. In the case of the present embodiment, a pair of encoders 10a and 10b having a mirror-symmetrical structure are supported and fixed to a rotating member such as the hub 1 (see FIG. 11) concentrically with the rotating member. In the case of this embodiment, the individual encoders 10a and 10b can be configured smaller (narrower in width) than the case of the integrated encoder 2 as shown in FIG. For this reason, the freedom degree regarding providing the installation site | part of an encoder in the said rotation member improves. For example, when the rotating member is the hub 1, one encoder 10 a is installed between the rolling elements 4 and 4 (see FIG. 11) arranged in a double row, and the other encoder 10 a is connected to the hub 1. It can also be installed at the axial end of
Except for the use of separate encoders 10a and 10b, the second embodiment is the same as the first embodiment or the second embodiment described above.

  FIG. 5 shows a fourth embodiment of the present invention corresponding to claims 1, 2, 7, 8, 11, 14, and 16. In the case of the present embodiment, of the pair of encoders 10a and 10c that are independent from each other, one encoder 10a (the upper side in FIG. 5) is adjacent in the circumferential direction as in the case of the third embodiment described above. The boundary between the S pole and the N pole is inclined with respect to the axial direction of the encoder 10a. On the other hand, the encoder 10c on the other side (lower side in FIG. 5) makes the boundary between the S pole and the N pole adjacent in the circumferential direction parallel to the axial direction of the encoder 10c. However, in any encoder 10a, 10c, the widths (characteristic change pitches) in the rotation direction between the S pole and the N pole adjacent in the circumferential direction are equal to each other. Further, when the phase of the boundary where the characteristics of the detected surfaces of the one encoder 10a and the other encoder 10c change is compared, both of these encoders 10a are positioned at the center position in the width direction of the one encoder 10a. The phases relating to the encoders 10a and 10c coincide with each other. In a state where the axial load is not applied, the detection unit 9 of one rotation detection sensor faces the center position in the width direction of the one encoder 10a.

  In the case of the present embodiment configured as described above, the detectors 9 and 9 of the pair of rotation detection sensors and the detection surfaces of the encoders 10a and 10c are connected to the encoders 10a and 10c in accordance with the action of the axial load. In the case of relative displacement in the axial direction of 10c, only the phase of the output signal of the rotation detection sensor in which the detection unit 9 is opposed to the detection surface of the one encoder 10a is shifted. The phase of the output signal of the rotation detection sensor having the detection unit 9 opposed to the detection surface of the other encoder 10c does not change regardless of the action of the axial load. For this reason, in the case of the present embodiment, the phase shift of the pair of rotation detection sensors due to the action of this axial load becomes smaller (halved) than in the case of the first to third embodiments. However, it is sufficient to make only one type of encoder in which the boundary between the S pole and the N pole adjacent in the circumferential direction is inclined with respect to the axial direction. The other encoder 10c that has been widely used for ABS can be used. For this reason, the manufacturing cost of a rolling bearing unit with a load measuring device can be suppressed. Other configurations and operations are the same as those of the above-described third embodiment, and thus redundant description is omitted.

  FIG. 6 shows a fifth embodiment of the present invention corresponding to claims 1, 2, 4, 5, 8, 11, 12, 14, and 16. In the case of the present embodiment, the detection units 9, 9 of the two rotation detection sensors are arranged at the same position with respect to the rotation direction of the encoder 2b. Instead, in the case of the present embodiment, the phase of the boundary position between the S pole and the N pole arranged alternately at equal intervals in the rotation direction on the detected surface of the encoder 2b is the center of the detected surface. On both sides of the position, they are shifted from each other by a ¼ pitch (or ½ may be allowed to correspond to claim 3). In the case of this embodiment as well, as in the case of Embodiment 1 or Embodiment 2 described above, the axial load and rotation speed applied to a rotating member such as a hub can be obtained in a state close to real time.

  FIG. 7 shows Embodiment 6 of the present invention corresponding to claims 1, 2, 4, 6, 8, 11, 12, 14, and 16. In the case of the present embodiment, a pair of encoders 10a and 10b having a mirror-symmetrical structure are supported and fixed to a rotating member such as the hub 1 (see FIG. 11) concentrically with the rotating member. The operations and effects obtained by using a pair of encoders 10a and 10b that are independent from each other are the same as those of the third embodiment described in FIG. 4, and the other configurations and operations are the same as those of the fifth embodiment. is there.

  FIG. 8 shows Embodiment 7 of the present invention corresponding to claims 1, 2, 4, 6, 8, 11, 14, and 16. In the case of the present embodiment, of the pair of encoders 10a and 10c independent from each other, the encoder 10c on the lower side of FIG. 8 has a boundary between the S pole and the N pole adjacent in the circumferential direction. The one parallel to the axial direction is used. The operation and effect by using such an encoder 10c is the same as that of the fourth embodiment described in FIG. 5, and the other configurations and operations are the same as those of the sixth embodiment.

  9 to 10 show an eighth embodiment of the present invention corresponding to claims 1, 2, 4, 5, 9, 11, 12, 13, 14, and 16. FIG. In the case of the present embodiment, as the encoder 2c, the through holes 6a and 6b inclined in the axial direction as shown in FIGS. A magnetic metal plate formed at intervals is used. In particular, in the case of the present embodiment, the phase in the rotational direction of the encoder 2c is determined by the through holes 6a, 6a provided in one half of the encoder 2c in the axial direction and the through holes 6b, 6b provided in the other half. Are shifted from each other by ½ of the pitch of the through holes 6a and 6b.

  Such operations and effects of the present embodiment are basically the same as those of the second embodiment shown in FIG. That is, in the case of the present embodiment, as the encoder 2c is made of a magnetic metal plate, permanent magnets are provided on the pair of rotation detection sensors 5a and 5a (see FIG. 15). The shape of the output signal sent out from the both rotation detection sensors 5a and 5a and the manner of change of this output signal accompanying the fluctuation of the rotational speed and the axial load are the same as in the case of the second embodiment. FIG. 10 shows the positional relationship between the detection portions 9 and 9 of the pair of rotation detection sensors 5a and 5a and the through holes 6a and 6b when the axial load is not applied and when it is applied. The output signals of the both rotation detection sensors 5a and 5a are shown. It should be noted that even if the position of the detection unit of the pair of rotation detection sensors combined with the encoder 2a shown in FIGS. 16 to 17 is shifted in the rotation direction of the encoder 2a, the same operation and effect as in this embodiment can be obtained. It is done.

  In each of the illustrated embodiments, the structure in which the peripheral surface of the encoder is the detected surface and the axial load applied to the rotating member is obtained has been described. However, the present invention is not limited to such a structure, and can be implemented with a structure for measuring a radial load. In this case, the detection units of the pair of rotation detection sensors are opposed to each other at different positions in the radial direction of one side surface in the axial direction of the annular encoder. Basically, it can be carried out in the same manner as when measuring the axial load, except that the position of the detection unit facing the surface to be detected changes from the radial direction to the axial direction.

  In the case of the present invention, the phases of the detection portions of a plurality (n) of rotation detection sensors and the boundary portion of the characteristic change existing on the detection surface of the encoder are shifted between these rotation detection sensors, The number of detections corresponding to the starting point at which the output signal changes is increased so that substantially the same operation and effect as when the number of pulses is increased can be obtained. On the other hand, a method of obtaining the same operation and effect as when the number of pulses is increased by using an estimation calculation (observer) while keeping the structure of the encoder and the rotation detection sensor as before is also effective. This method was announced at the Institute of Electrical Engineers of Japan held on March 3, 2004 at the Hatoyama Campus of Tokyo Denki University, "State Estimation Using a Dual Rate Sampling Observer with a Slow Sensor" (P.31-36 of the IEEJ Technical Committee Materials).

  On the other hand, in the aforementioned Japanese Patent Application No. 2004-279155, an S pole and an N pole are magnetized in a trapezoidal shape or a sector shape on the detected surface of the encoder, or a trapezoidal or fan-shaped through hole or uneven portion is provided on the detected surface. A structure is described in which the load applied to the member that supports the encoder is determined based on the duty ratio of the output signal of a single rotation detection sensor that is formed and has its detection portion opposed to the detected surface. In the case of the present invention, the load measurement based on the duty ratio of the output signal of such a single rotation detection sensor cannot obtain the load measurement in real time. On the other hand, if the estimation calculation as described above is used, even if the load is obtained based on the duty ratio of the output signal of the single rotation detection sensor, the same as the case where the number of pulses is increased. Action and effect can be obtained.

  Of course, if the above estimation calculation is performed in combination with the present invention, the number of times that the load and the rotation speed can be obtained per unit rotation angle of the encoder can be further increased. In the estimation calculation performed in such a case, one or a plurality of estimated pulse edges are calculated between the pulse edge output from the encoder (starting point where the output signal changes) and the next pulse edge. Identify (tentatively set). When such a method is applied to a structure for obtaining the rotational speed and load of the hub of a rolling bearing unit for supporting a wheel of an automobile, information for estimating the state includes the accelerator opening of the engine, the transmission of the transmission. It is conceivable to use gear ratio, brake fluid pressure, etc.

The schematic diagram which shows Example 1 of this invention, and shows the relationship between the to-be-detected surface of an encoder, and the detection part of a pair of rotation detection sensor. FIG. 3 is a diagram illustrating output signals of a pair of rotation detection sensors in the first embodiment. FIG. 6 is a diagram showing output signals of a pair of rotation detection sensors in Embodiment 2 of the present invention. The schematic diagram which shows the relationship between the to-be-detected surface of an encoder and the detection part of a pair of rotation detection sensor which shows Example 3 of this invention. The figure similar to FIG. 1 which shows the same Example 4. FIG. The figure similar to FIG. 1 which shows the same Example 5. FIG. The figure similar to FIG. 1 which shows the same Example 6. FIG. The figure similar to FIG. 1 which shows the same Example 7. FIG. The perspective view of the encoder which shows the same Example 8. FIG. The same figure as FIG. Sectional drawing which shows the 1st example of the structure 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 the structure 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.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hub 2, 2a, 2b, 2c Encoder 3 Outer ring 4 Rolling element 5, 5a Rotation detection sensor 6a, 6b Through-hole 7a, 7b Pillar part 8 Rim part 9 Detection part 10a, 10b, 10c Encoder

Claims (16)

An encoder that is supported by the rotating member and rotates together with the rotating member, and the characteristics of the detected surface provided concentrically with the rotation center of the rotating member are changed alternately and at equal intervals over the circumferential direction; In a rotation detection device comprising: a rotation detection sensor installed in a state adjacent to the rotation member and supported by a part of a stationary member that does not rotate, and having a detection unit opposed to the detection surface. ,
When n is a natural number of 2 or more, n rotation detection sensors are provided, and the phase at which each detection unit of the n rotation detection sensors faces the detection surface of the encoder A rotation detection device characterized in that the phase of the detection surface is deviated from each other by a known value in the rotation direction of the encoder with respect to the phase where the characteristic of the detection surface changes.   The rotation detection device according to claim 1, wherein the known value is a ½n pitch of a pitch at which the characteristic of the detection target surface of the encoder changes.   The rotation detection device according to claim 1, wherein the known value is 1 / n pitch of the pitch at which the characteristic of the detection target surface of the encoder changes.   The detection units of the n rotation detection sensors are arranged at the same position with respect to the rotation direction of the encoder, and the phase at which the characteristics of the detection surface of the encoder changes varies between the positions of the detection units of the rotation detection sensors. The rotation detection device according to claim 1, wherein the rotation detection devices are shifted from each other with respect to the rotation direction.   The rotation detection device according to claim 4, further comprising: one encoder whose characteristics change in phase are shifted from each other between portions having different positions in the width direction of the detection surface.   The rotation detection device according to claim 4, wherein the n encoders are provided in a state in which phases in which the characteristics of the detected surface change are shifted from each other with respect to the rotation direction of each encoder.   The rotation detection device according to any one of claims 1 to 3, wherein the detection units of the n rotation detection sensors are installed at positions shifted from each other with respect to the rotation direction of the encoder.   The encoder according to any one of claims 1 to 7, wherein the encoder is made of a permanent magnet, and N poles and S poles are alternately arranged at equal intervals in the circumferential direction on the detection surface of the encoder. The described rotation detector.   The rotation according to any one of claims 1 to 7, wherein the encoder is made of a magnetic metal plate, and through-holes and column portions are alternately arranged in a circumferential direction on a detection surface of the encoder. Detection device.   The rotation detection device according to any one of claims 1 to 9, wherein an IC constituting n rotation detection sensors is supported by a tip portion of a single holder. 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 a rotation detecting device and a computing unit,
Among these, the rotation detection device is the rotation detection device according to any one of claims 1 to 10 and, as an encoder, detects a phase in which a characteristic of a detected surface changes in a circumferential direction. The operation unit incorporates what is continuously changed according to the acting direction of the power load. A rolling bearing unit with a load measuring device having a function of calculating a load acting between the rotating side raceway.   n is 2, and the detection units of the two rotation detection sensors are arranged at the same position with respect to the rotation direction of the encoder, and the direction in which the phase in which the characteristics of the detection surface of the encoder changes changes in the detected direction. The detection surfaces are opposite to each other with respect to the arrangement direction of the two rotation detection sensors, with the center portion in the width direction of the detection surface as a boundary, and the phase of change is 1/4 pitch or 1 on both sides of the center portion in the width direction. The rolling bearing unit with a load measuring device according to claim 11, wherein the rolling bearing units are displaced from each other by a pitch of / 2.   n is 2, and the detection units of the two rotation detection sensors are arranged at positions shifted by ¼ pitch or ½ pitch with respect to the rotation direction of the encoder. The direction in which the changing phase changes is opposite to the arrangement direction of the both rotation detection sensors, with the center portion in the width direction of the detection surface as a boundary, and on both sides of the center portion in the width direction. The rolling bearing unit with a load measuring device according to claim 11, wherein the phases of change coincide with each other.   The rolling bearing unit is a wheel bearing rolling bearing unit that rotatably supports a wheel on a suspension device of an automobile, and the load calculated by the computing unit is a load applied between the suspension device and the wheel. Item 14. A rolling bearing unit with a load measuring device according to any one of Items 11 to 13.   The load calculated by the computing unit is a radial load applied between the suspension device and the wheel, the detected surface of the tone wheel is the side surface in the axial direction of this tone wheel, and the phase of the characteristic change of this detected surface is The rolling bearing unit with a load measuring device according to claim 14, wherein the rolling bearing unit changes in the radial direction of the detected surface.   The load calculated by the arithmetic unit is an axial load applied between the suspension device and the wheel, the detected surface of the tone wheel is the peripheral surface of the tone wheel, and the phase of the characteristic change of the detected surface is the detected surface. The rolling bearing unit with a load measuring device according to claim 14, wherein the rolling bearing unit changes with respect to the axial direction of the detection surface.

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