JP2009069092A - Rotation detector and bearing with rotation detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotation detector with simple construction capable of precisely detecting absolute angle without magnetic interference between magnetic encoders or being affected by noise, and a bearing with rotation detector mounted on the bearing. <P>SOLUTION: The rotation detector 1 includes: a plurality of magnetic encoders 2A, 2B provided in concentric ring shapes having mutually different number of magnetic poles; a plurality of magnetic sensors 3A, 3B for respectively detecting the magnetic field of each of magnetic encoders 2A, 2B, each of magnetic sensors 3A, 3B has a function for detecting positional information in the magnetic poles of the magnetic encoders 2A, 2B; a phase difference detection means 6 for obtaining the phase difference of the magnetic signals detected by each of the magnetic sensors 3A, 3B; and an angle calculation means 7 for calculating the absolute angles of the magnetic encoder using the detected phase differences and correcting the calculated absolute angle with the out put of a magnetic sensor of either side of the magnetic encoders. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rotation detection device used for rotation angle detection in various devices, particularly rotation angle detection for rotation control of various motors, and a bearing with a rotation detection device equipped with the rotation detection device.

  This type of rotation detection device includes a first encoder having a main track and a rotation pip track, and a second encoder for detecting a rotor phase of the motor, and a detection signal of a sensor disposed opposite to these encoders Based on the above, there has been proposed one that generates a signal train necessary for motor control (for example, Patent Document 1).

  Further, in a rotation detection device using a wound stator and a rotor, an absolute encoder is configured by forming a plurality of track groups having different numbers of poles in the rotor, and an absolute angle is determined by a phase difference of signals detected from the track groups. What has been detected is also proposed (for example, Patent Document 2).

  As another rotation detection device, a combination of a plurality of magnets arranged in the circumferential direction of the outer periphery of the rotor and a plurality of magnetic sensors provided at different positions in the circumferential direction on the inner periphery of the stator, There has also been proposed an apparatus in which an absolute angle is detected by calculating an output signal (for example, Patent Document 3).

Furthermore, as another rotating diameter device, a ring-shaped magnetic pulse generating means such as a magnetic encoder in which magnetic pole pairs are arranged in the circumferential direction for generating magnetic pulses, and substantially aligned in the circumferential direction with respect to the magnetic pulse generating means There is also proposed a device that includes a plurality of detection elements that detect the magnetic pulse and detect an absolute angle by calculating an output signal of the detection element (for example, Patent Document 4).
JP 2006-271503 A JP 2006-322927 A JP-T-2006-525518 Special Table 2002-541485

However, the above-described rotation detection device has the following problems.
-Currently, resolvers are widely used to detect rotational positions of motors and the like, but there is a problem of high manufacturing costs.
In each of the rotation detection devices described above, if a magnetic encoder is used, it is difficult to detect an absolute angle and obtain a high-resolution rotation pulse.
In the case of the rotation detection device disclosed in Patent Document 1, there is a problem that the structure is complicated and the absolute angle cannot be detected without rotating.
The rotation detection device disclosed in Patent Document 2 is an example in which the influence of positional deviation from the rotor is reduced by the same method as that using a resolver, but has a problem that a complicated coil is required.
In the case of the rotation detection device disclosed in Patent Document 3 that detects the rotation of the magnet with a magnetic sensor, the rotation angle can be detected. However, in order to obtain the rotation angle with high accuracy, the magnetic field strength is detected with high accuracy. The detection gap must be managed accurately. Further, in order to output the rotation pulse signal by this method, a processing circuit for generating the pulse signal from the detection angle is required.

Therefore, the present inventors have proposed the following configuration as a rotation detection device that can solve these problems and detect an absolute angle with high accuracy (Japanese Patent Application No. 2007-043735).
In this rotation detection device, a plurality of magnetic encoders provided in concentric rings and having different numbers of magnetic poles and a plurality of magnetic sensors for detecting the magnetic fields of these magnetic encoders are provided. A device having a function of detecting position information in the magnetic pole is used. Further, the phase difference of the magnetic field signal detected by each of the magnetic sensors is obtained by the phase difference detection means, and the absolute angle of the magnetic encoder is calculated by the angle calculation means based on the detected phase difference.

  In the case of the rotation detection device configured as described above, for example, when the magnetic pole pair is rotated by using the magnetic encoder of 12 and the magnetic encoder of 13, the signal of these two magnetic sensors is equivalent to one magnetic pole pair per rotation. Phase shift occurs. Therefore, this phase difference can be detected by the phase difference detection means, and the absolute angle in one rotation can be calculated by the angle calculation means based on the phase difference. In addition, each magnetic sensor has a function of detecting position information in the magnetic pole of each magnetic encoder, so that an absolute angle can be detected with high accuracy. Also, the configuration is simple.

  However, in the case of the rotation detection device having this configuration, the absolute angle cannot be detected with high precision in a state where the magnetic angle and noise of the magnetic encoders are added to the obtained absolute angle information. In addition, when the ABZ-phase pulse signal is also output from the rotation detection device, it is desirable that the absolute angle information and the ABZ-phase pulse signal are synchronized.

  An object of the present invention is to provide a rotation detector capable of detecting an absolute angle with high accuracy without being affected by magnetic interference and noise between magnetic encoders, and a bearing with a rotation detector equipped with the rotation detector. Is to provide.

The rotation detection device of the present invention includes a plurality of magnetic encoders that are provided in concentric rings and have different numbers of magnetic poles, and a plurality of magnetic sensors that respectively detect the magnetic fields of these magnetic encoders. A rotation detection device having a function of detecting position information in a magnetic pole of an encoder, a phase difference detection means for obtaining a phase difference of magnetic field signals detected by each magnetic sensor, and the detected phase difference And an angle calculating means for correcting the calculated absolute angle with the output of one of the magnetic sensors on the magnetic encoder side.
For example, if the magnetic pole pair is rotated by using a magnetic encoder having 12 magnetic poles and a magnetic encoder having 13 magnetic poles, a phase shift corresponding to one magnetic pole pair occurs in one rotation between the signals of two magnetic sensors that detect these magnetic fields. The phase difference can be detected by the phase difference detection means, and the absolute angle in one rotation can be calculated by the angle calculation means based on the phase difference. In addition, each magnetic sensor has a function of detecting position information in the magnetic pole of each magnetic encoder, so that an absolute angle can be detected with high accuracy. Also, the configuration is simple. In particular, the absolute angle calculated based on the phase difference detected by the phase difference detecting means is corrected by the output of any one magnetic sensor on the magnetic encoder side. The absolute angle can be detected with high accuracy without being influenced by.

In the present invention, the magnetic sensor has a plurality of sensor elements arranged at positions shifted from each other within the magnetic pole pitch, and can obtain a two-phase signal output of sin and cos. May be detected by multiplying.
When the magnetic sensor has such a configuration, the magnetic field distribution of the magnetic encoder can be detected more finely as a sinusoidal signal based on an analog voltage rather than as an on / off signal, and an accurate absolute angle can be detected.

In the present invention, the magnetic sensor is composed of a line sensor in which sensor elements are arranged along the arrangement direction of the magnetic poles of the magnetic encoder, and a two-phase signal output of sin and cos is generated by calculation to determine the position in the magnetic pole. It may be detected.
When the magnetic sensor is configured as such a line sensor, the influence of the distortion of the magnetic field pattern and noise is reduced, and the phase of the magnetic encoder can be detected with higher accuracy.

In the present invention, the absolute angle calculated by the angle calculating means is calculated based on two pulse signals of A phase and B phase, which are 90 ° different from each other, based on the detection signal of any one magnetic sensor, and the origin position. An angle information output circuit that outputs an ABZ phase signal composed of a Z-phase pulse signal shown in the figure, and a magnetic sensor used for absolute angle correction in the angle calculation means may be selected as the magnetic sensor.
In the case of this configuration, it is not necessary to separately provide an I / F that outputs an absolute angle, and the circuit configuration of the rotation detection device and the circuit configuration of the device on which the rotation detection device is mounted can be simplified. Further, an ABZ phase signal synchronized with the absolute angle information can be output.

  In the present invention, the magnetic sensor selected for use in the absolute angle correction may be a magnetic sensor corresponding to a magnetic encoder having a large number of magnetic poles among a plurality of magnetic encoders having different numbers of magnetic poles. In the case of this configuration, an ABZ phase signal with higher resolution can be obtained.

  In this invention, the sensor module has an angle information output circuit for outputting the absolute angle calculated by the angle calculation means, and the magnetic sensor, the phase detection means, the angle calculation means, and the angle information output circuit are integrated with each other. May be provided. With this configuration, advantages such as reduction in the number of parts, improvement in the mutual position accuracy of magnetic sensors, reduction in manufacturing cost, reduction in assembly cost, and improvement in detection accuracy due to signal noise reduction are obtained. It can be a detection device.

  In the present invention, the sensor module may be integrated on a semiconductor chip. When integrated on a semiconductor chip, the size is further reduced and the reliability is improved.

The bearing with a rotation detection device of the present invention is obtained by mounting the rotation detection device of any one of the above configurations of the present invention on a bearing.
According to this configuration, it is possible to reduce the number of parts, the number of assembling steps, and the size of the bearing using device.

The rotation detection device of the present invention includes a plurality of magnetic encoders that are provided in concentric rings and have different numbers of magnetic poles, and a plurality of magnetic sensors that respectively detect the magnetic fields of these magnetic encoders. A rotation detection device having a function of detecting position information in a magnetic pole of an encoder, a phase difference detection means for obtaining a phase difference of magnetic field signals detected by each magnetic sensor, and the detected phase difference The absolute angle of the magnetic encoder is calculated on the basis of the angle, and the angle calculating means for correcting the calculated absolute angle with the output of the magnetic sensor on any one of the magnetic encoders is provided. The absolute angle can be accurately detected without being affected by magnetic interference or noise.
Since the bearing with a rotation detection device according to the present invention has the above-described rotation detection device according to the present invention mounted on the bearing, it is possible to reduce the number of parts, the number of assembling steps, and downsizing of the equipment using the bearing.

  An embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a schematic configuration of the rotation detection device of this embodiment. The rotation detection device 1 includes a plurality of (here, two) magnetic encoders 2A and 2B provided in a ring shape concentric with an axis O on the outer periphery of a rotating member 4 such as a rotating shaft of a motor. A plurality of (here, two) magnetic sensors 3A and 3B that respectively detect the magnetic fields of the magnetic encoders 2A and 2B are provided. In the example of FIG. 1, the magnetic sensors 3A, 3B are fixed members 5 such as motor housings so as to face each of the magnetic encoders 2A, 2B in the radial direction (radial direction) through a minute gap. Is provided. Here, the magnetic sensor 3A faces the magnetic encoder 2A, and the magnetic sensor 3B faces the magnetic encoder 2B.

  The magnetic encoders 2A and 2B are ring-shaped magnetic members in which a plurality of magnetic pole pairs (one set of a magnetic pole S and a magnetic pole N) are magnetized at an equal pitch in the circumferential direction. In the example of FIG. A magnetic pole pair is magnetized on the outer peripheral surface. The number of magnetic pole pairs of these two magnetic encoders 2A and 2B is different from each other. In the example of FIG. 1, the two magnetic encoders 2A and 2B are arranged adjacent to each other in the axial direction. However, if the magnetic encoders 2A and 2B rotate in the same direction, they are arranged in different places. You may do it.

  As another example of the magnetic encoders 2A and 2B, as shown in FIG. 2, an axial type magnet in which a plurality of magnetic pole pairs are magnetized so as to be arranged at an equal pitch in the circumferential direction on the end surface in the axial direction of a ring-shaped magnetic member May be used. In this example, two magnetic encoders 2A and 2B are arranged adjacent to the inner and outer peripheries. In the case of the axial type magnetic encoders 2A and 2B, the magnetic sensors 3A and 3B are arranged in the axial direction facing the magnetized surface.

The magnetic sensors 3A and 3B have a function of detecting magnetic poles with a resolution higher than the number of magnetic pole pairs of the corresponding magnetic encoders 2A and 2B, that is, a function of detecting position information within the magnetic pole ranges of the magnetic encoders 2A and 2B. It is supposed to be. In order to satisfy this function, for example, the magnetic sensor 3A may be configured as shown in FIG. 3 when the pitch λ of one magnetic pole pair of the corresponding magnetic encoder 2A is one cycle. That is, two magnetic sensor elements 3A1 and 3A2 such as Hall elements arranged apart from each other in the arrangement direction of the magnetic poles so as to have a phase difference of 90 degrees (λ / 4) are obtained by using these two magnetic sensor elements 3A1 and 3A2. It may be calculated by multiplying the phase in the magnetic pole (φ = tan ⁻¹ (sinφ / cos φ)) from the two-phase signal (sinφ, cosφ). The same applies to the other magnetic sensors 3B. The waveform diagram of FIG. 3 shows the magnetic pole array of the magnetic encoder 2A in terms of magnetic field strength.

  When the magnetic sensors 3A and 3B have such a configuration, the magnetic field distribution of the magnetic encoders 2A and 2B can be detected more finely as a sinusoidal signal based on an analog voltage rather than as an on / off signal, and accurate absolute angle detection can be performed. It becomes possible.

  As another example of the magnetic sensors 3A and 3B having a function of detecting position information in the magnetic poles of the magnetic encoders 2A and 2B, a line sensor as shown in FIG. 4B may be used. That is, for example, as the magnetic sensor 3A, line sensors 3AA and 3AB in which the magnetic sensor elements 3a are arranged along the arrangement direction of the magnetic poles of the corresponding magnetic encoder 2A are used. FIG. 4A is a waveform diagram in which one magnetic pole section in the magnetic encoder 2A is converted into a magnetic field strength. In this case, the first line sensor 3AA of the magnetic sensor 3A is arranged in association with the 90-degree phase section of the 180-degree phase section in FIG. 4A, and the second line sensor 3AB is the remaining 90. It is arranged in correspondence with the phase interval of degrees. With such an arrangement, the signal S1 obtained by adding the detection signal of the first line sensor 3AA by the adder circuit 31 and the signal S2 obtained by adding the detection signal of the second line sensor 3AB by the adder circuit 32 are different addition circuits. By adding in step 33, a sin signal corresponding to the magnetic field signal as shown in FIG. Further, the signal S1 and the signal S2 via the inverter 35 are added by another adding circuit 34 to obtain a cos signal corresponding to the magnetic field signal as shown in FIG. The position in the magnetic pole is detected from the two-phase output signal thus obtained.

  When the magnetic sensors 3A and 3B are configured by line sensors in this way, the influence of distortion and noise of the magnetic field pattern is reduced, and the phases of the magnetic encoders 2A and 2B can be detected with higher accuracy.

  For example, in the configuration example of FIG. 1, the magnetic sensors 3 </ b> A and 3 </ b> B are connected to the phase difference detection means 6. The phase difference detection means 6 is a means for obtaining a phase difference between magnetic field signals detected by the magnetic sensors 3A and 3B, and an angle calculation means 7 is connected to the subsequent stage. The angle calculation means 7 is a means for calculating the absolute angle of the magnetic encoders 2A and 2B based on the phase difference detected by the phase difference detection means 6. In addition, the angle calculation unit 7 includes a correction unit 12 that corrects the calculated absolute angle with the output of the magnetic sensor 3A on any one of the magnetic encoders (for example, 2A).

  A schematic operation of absolute angle detection by the rotation detection device 1 will be described below with reference to FIGS. In FIG. 1, when the number of magnetic pole pairs of the two magnetic encoders 2B and 2A is P and P + n, there is a phase difference of n magnetic pole pairs per rotation between the magnetic encoders 2A and 2B. The phases of the detection signals of the magnetic sensors 3A and 3B corresponding to the magnetic encoders 2A and 2B coincide with each other when rotated 360 / n degrees.

5A and 5B show examples of magnetic pole patterns of both magnetic encoders 2A and 2B, and FIGS. 5C and 5D show detection signals of magnetic sensors 3A and 3B corresponding to these magnetic encoders. The waveform is shown. In this case, the two magnetic pole pairs of the magnetic encoder 2B correspond to the three magnetic pole pairs of the magnetic encoder 2A, and the absolute position in this section can be detected. FIG. 5E shows a waveform diagram of the output signal of the phase difference obtained from the phase difference detecting means 6 of FIG. 1 based on the detection signals of FIGS. 5C and 5D.
FIG. 6 shows a waveform diagram of detection phases and phase differences by the magnetic sensors 3A and 3B. 6A and 6B show examples of magnetic pole patterns of both magnetic encoders 2A and 2B, and FIGS. 6C and 6D show waveforms of detection phases of the corresponding magnetic sensors 3A and 3B. FIG. 6E shows a waveform diagram of the phase difference signal output from the phase difference detecting means 6.

  Since the phase difference signal (FIG. 6 (E)) detected by the phase difference detecting means 6 is affected by the magnetic interference and noise of the magnetic encoders 3A and 3B, it is actually shown in FIG. 7 (A). It becomes a waveform with distortion like delta. That is, for example, when detection errors of ε1 and ε2 are added to the detection signals of the magnetic sensors 3A and 3B, respectively, a detection error of about ε1 + ε2 is added to the phase difference signal delta.

Therefore, the angle calculation means 7 calculates the absolute angle with high detection accuracy by performing the following processing. In FIG. 7, the number of magnetic pole pairs of the two magnetic encoders 2B and 2A is 2 and 3, and there is a phase difference of one magnetic pole pair per rotation between the magnetic encoders 2A and 2B. In the example, the phases of the detection signals of the magnetic sensors 3A and 3B corresponding to the encoders 2A and 2B coincide with each other when rotated 360 degrees.
As a first process, the angle calculation means 7 calculates the approximate phase of one magnetic encoder (here, the magnetic encoder 2A with many magnetic pole pairs) from the phase difference signal delta of FIG. And the detected positions a, b, and c of each magnetic pole pair of the magnetic encoder 2A shown in FIG. 7B are estimated as the waveform shown by MA in FIG.
In the second process, the phase difference signal delta in FIG. 7A is corrected by the correction unit 12 of the angle calculation unit 7 as follows. The phase difference signal correctA = MA + (θ1 / 3) corrected as shown in FIG. 7C by adding the phase signal θ1 / 3 of the magnetic encoder 2A to the estimated approximate phase MA.
Get.
In the third process, the absolute angle is calculated based on the phase difference signal correctA corrected in this way.

  In this case, although the detection error is included in the phase difference signal correctA corrected as described above, the detection error is ε1 / 3 because it is divided by the number of magnetic poles 3 of the magnetic encoder 2A. This detection error is clearly smaller than the detection error ε1 + ε2 of the phase difference signal delta before correction. Therefore, the absolute angle can be detected with the same accuracy as the detection accuracy of each of the magnetic sensors 3A and 3B.

  FIG. 8 shows a configuration example of an absolute angle detection circuit in the rotation detection device 1. Based on the detection signals of the magnetic sensors 3A and 3B as shown in FIGS. 5C and 5D, the corresponding phase detection circuits 13A and 13B are shown in FIGS. 6C and 6D, respectively. Output an accurate detection phase signal. The phase difference detection means 6 outputs a phase difference signal as shown in FIG. 6E based on these detected phase signals. The angle calculation means 7 provided at the next stage corrects the phase difference obtained by the phase difference detection means 6 by the processing shown in FIG. 7, and then converts it to an absolute angle according to a preset calculation parameter. Process.

  Calculation parameters used in the angle calculation means 7 are stored in a memory 8 such as a nonvolatile memory. In addition to the calculation parameters, the memory 8 stores information necessary for the operation of the apparatus, such as setting of the number of magnetic pole pairs of the magnetic encoders 2A and 2B, an absolute angle reference position, and a signal output method. Here, by providing a communication interface (I / F) 9 at the next stage of the memory 8, the contents of the memory 8 can be updated through the communication interface 9. Thereby, the individual setting information can be variably set according to the use situation, and the usability is improved.

  The absolute angle information calculated by the angle calculation means 7 is output from the angle information output circuit 10 or via the communication interface 9 as a modulation signal such as a parallel signal, serial data, analog voltage, or PWM. Further, a rotation pulse signal is also output from the angle calculation means 7. As the rotation pulse signal, any one of the detection signals of the two magnetic sensors 3A and 3B may be output. As described above, since each magnetic sensor 3A, 3B has a multiplication function, it is possible to output a rotation signal with high resolution.

  In the angle information output circuit 10 of FIG. 7, the absolute angle calculated by the angle calculating means 7 is divided into two A-phase and B-phase pulse signals having a phase difference of 90 degrees and a Z-phase pulse signal indicating the origin position. It may be output as an ABZ phase signal.

When the absolute angle is calculated from the phase difference signal delta before correction shown in FIG. 7A, the obtained absolute angle signal is not synchronized with the ABZ phase signal obtained from each of the magnetic encoders 2A and 2B. Therefore, in this embodiment, an ABZ phase signal is output from the detection signal of the magnetic sensor 3A on the magnetic encoder 2A side used for correcting the phase difference signal delta. As a result, the corrected phase difference signal correctA and the ABZ phase signal are synchronized.
In this embodiment, since the phase difference signal delta is corrected by the sensor output of the magnetic sensor 3A on the magnetic encoder 2A side having a large number of magnetic poles, the ABZ phase signal can be obtained with higher resolution.

When outputting an ABZ phase signal, as shown in FIG. 9, when a request signal for absolute angle output is input from the receiving circuit 14 to the angle calculation means 7, the absolute calculation in the angle calculation means 7 is correspondingly performed. The angle execution means 15 becomes operable, and a mode execution signal (ABS_mode = 1) indicating that the absolute angle output mode is in effect is generated from the mode execution signal generation means 16 in the angle calculation means 7, and the rotation pulse in the angle calculation means 7. The angle calculation means 7 may be configured such that A, B, and Z phase signals are output from the signal generation means 17.
In the receiving side circuit 14, the position counter 18 indicating the absolute angle value is reset to 0 by receiving the Z-phase signal, and the A-phase signal and the B-phase signal output following the Z-phase signal are converted into the position counter 18. Counts. Once the pulse outputs of the A-phase signal and B-phase signal reach the current absolute angle value, the absolute angle output mode operation ends there (ABS_mode = 0). Thereafter, a rotation pulse signal (ABZ phase signal) corresponding to the change in the absolute angle detected with the rotation of the rotating member 4 (FIG. 1) is output from the angle calculating means 7. As a result, the receiving-side circuit 14 that knows the absolute angle by counting the pulses is in a state in which the actual absolute angle information is always acquired after the absolute angle output mode operation ends (ABS_mode = 0). .

  In this way, when the rotation information such as the ABZ phase signal is output from the angle information output circuit 10 and the absolute angle information is output in the absolute angle output mode, there is no need to separately provide an interface for outputting the absolute angle. The circuit configuration of the rotation detection device 1 and the circuit configuration on the device side on which the rotation detection device 1 is mounted can be simplified.

Further, in this rotation detection device 1, the magnetic sensors 3A and 3B and the signal processing circuit including the angle information output circuit 10 shown in FIG. 9 are integrated as a sensor module 11 as shown in the example of FIG. The sensor module 11 may be integrated on one semiconductor chip. When configured in this way, advantages such as a reduction in the number of parts, an improvement in the positional accuracy of the magnetic sensors 3A and 3B, a reduction in manufacturing costs, a reduction in assembly costs, and an improvement in detection accuracy due to signal noise reduction are obtained. Thus, a low-cost rotation detection device 1 can be obtained.
In this case, since one sensor module 11 is opposed to the two magnetic encoders 2A and 2B, the two magnetic encoders 2A and 2B are arranged close to each other.

  As described above, the rotation detection device 1 includes a plurality of magnetic encoders 2A and 2B that are provided in concentric rings and have different numbers of magnetic poles, and a plurality of magnetic sensors 3A that detect magnetic fields of the magnetic encoders 2A and 2B, respectively. , 3B, and each of the magnetic sensors 3A, 3B has a function of detecting position information in the magnetic poles of the magnetic encoders 2A, 2B, and the phase difference between the magnetic field signals detected by the magnetic sensors 3A, 3B. Is calculated by the phase difference detection means 6, and the angle calculation means 7 calculates the absolute angle of the magnetic encoder 2A, 2B based on the phase difference detected by the phase difference detection means 6, and the calculated absolute angle is either Since correction is made with the output of one magnetic encoder side magnetic sensor (here, magnetic sensor 3A), the structure becomes simple and the magnetic encoder 2A It is possible to accurately detect the absolute angle without being affected by magnetic interference and noise among 2B.

  In this embodiment, an example using two magnetic encoders 2A and 2B is illustrated, but the number of magnetic encoders is not limited to two, and a combination of three or more magnetic encoders having different numbers of magnetic pole pairs is wider. It may be configured to detect the absolute angle of the range. When this rotation detection device 1 is used to detect the rotation of the motor, if the combination of P and P + Pn is adjusted in accordance with the number of rotor poles Pn in the adjustment of the difference in the number of magnetic pole pairs, the rotation detection device 1 causes the motor to This is convenient for controlling the rotation of the motor.

  FIG. 10 is a cross-sectional view showing an embodiment of a bearing with a rotation detection device in which the rotation detection device 1 is mounted on a bearing. This bearing 20 with a rotation detection device is provided at one end of a rolling bearing 21 in which a plurality of rolling elements 24 are interposed between an inner ring 22 that is a rotation side raceway and an outer ring 23 that is a fixed side raceway. Is provided. The rolling bearing 21 is a deep groove ball bearing, and rolling surfaces 22 a and 23 a of the rolling elements 24 are formed on the outer diameter surface of the inner ring 22 and the inner diameter surface of the outer ring 23, respectively. The bearing space between the inner ring 22 and the outer ring 23 is sealed with a seal 26 at the end opposite to the installation side of the rotation detection device 1.

The two magnetic encoders 2 </ b> A and 2 </ b> B of the rotation detection device 1 are provided side by side in the axial direction on the outer diameter surface of a ring-shaped cored bar 27 that is press-fitted into the outer diameter surface of one end portion of the inner ring 22. As shown in FIG. 2, the two magnetic sensors 3A and 3B of the rotation detecting device 1 are integrated as a sensor module 11 together with other signal processing circuits, and are inserted inside a ring-shaped metal sensor housing 28. The resin mold 29 is attached to the inner diameter surface of one end of the outer ring 23 via the sensor housing 28. As a result, the magnetic encoders 2A and 2B and the corresponding magnetic sensors 3A and 3B are arranged to face each other in the radial direction. The lead wire 30 connected to the sensor module 11 passes through the sensor housing 27 and is drawn to the outside, and signals are exchanged and power is supplied between the sensor module 11 and an external circuit via the lead wire 30.

  In this rotation detecting device bearing 20, since the rotation detecting device 1 is mounted on the rolling bearing 21, it is possible to reduce the number of parts, the number of assembling steps, and downsizing of the equipment using the bearing. In addition, the bearing with a rotation detection device of the present invention may be applied to a wheel bearing that supports a wheel of an automobile or the like with respect to the vehicle body.

It is the schematic of the example of 1 structure of the rotation detection apparatus concerning one Embodiment of this invention. It is a principal part side view of the other structural example of the rotation detection apparatus. It is explanatory drawing of the example of 1 structure of a magnetic sensor. It is explanatory drawing of the other structural example of a magnetic sensor. It is a wave form diagram of the detection signal of a magnetic sensor, and the detection signal of a phase difference detection means. It is a wave form diagram which shows the phase of the detection signal of each magnetic sensor, and the phase difference of both detection signals. It is explanatory drawing of the correction process which correct | amends the phase difference signal detected by a phase difference detection means by the correction means of an angle calculation means. It is a block diagram which shows one structural example of the absolute angle detection circuit of this rotation detection apparatus. It is a block diagram which shows the example of 1 structure of the angle information output circuit in this rotation detection apparatus. It is sectional drawing which shows one Embodiment of the bearing with a rotation detection apparatus which mounted this rotation detection apparatus in the bearing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rotation detection apparatus 2A, 2B ... Magnetic encoder 3A, 3B ... Magnetic sensor 3A1, 3A2 ... Magnetic sensor element 3AA, 3AB ... Line sensor 6 ... Phase difference detection means 7 ... Angle calculation means 10 ... Angle information output circuit 11 ... Sensor Module 12 ... Correction means 20 ... Bearing with rotation detector 21 ... Rolling bearing

Claims (8)

A plurality of magnetic encoders provided in concentric rings and having different numbers of magnetic poles, and a plurality of magnetic sensors that respectively detect the magnetic fields of these magnetic encoders, each of the magnetic sensors is information on a position in the magnetic pole of the magnetic encoder A rotation detecting device having a function of detecting
Phase difference detection means for obtaining a phase difference between magnetic field signals detected by the magnetic sensors, an absolute angle of the magnetic encoder is calculated based on the detected phase difference, and the calculated absolute angle is used as one of the magnetic encoders. An angle calculating means for correcting with the output of the side magnetic sensor is provided.   2. The magnetic sensor according to claim 1, wherein the magnetic sensor has a plurality of sensor elements arranged at positions shifted from each other within the magnetic pole pitch, and can obtain a two-phase signal output of sin and cos, A rotation detector that detects the position by multiplying it.   2. The magnetic sensor according to claim 1, wherein the magnetic sensor is composed of a line sensor in which sensor elements are arranged along an arrangement direction of magnetic poles of a magnetic encoder, and a two-phase signal output of sin and cos is generated by calculation to obtain a position in the magnetic pole. Rotation detection device that detects   4. The absolute angle calculated by the angle calculation unit according to claim 1, wherein the absolute angle calculated by the angle calculation unit is based on a detection signal of any one of the magnetic sensors. And an angle information output circuit that outputs an ABZ-phase signal composed of a Z-phase pulse signal indicating the origin position, and a magnetic sensor used for absolute angle correction in the angle calculation means. A rotation detection device that selects a sensor.   5. The rotation detection device according to claim 4, wherein the magnetic sensor selected for use in the absolute angle correction is a magnetic sensor corresponding to a magnetic encoder having a large number of magnetic poles among a plurality of magnetic encoders having different numbers of magnetic poles.   6. The method according to claim 1, further comprising an angle information output circuit that outputs an absolute angle calculated by the angle calculation unit, the magnetic sensor, the phase detection unit, the angle calculation unit, and the angle information. A rotation detector provided with a sensor module in which output circuits are integrated with each other.   The rotation detection device according to claim 6, wherein the sensor module is integrated on a semiconductor chip.   A bearing with a rotation detection device, wherein the rotation detection device according to any one of claims 1 to 7 is mounted on the bearing.

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