JP2009276261A - Rotational angle detection device and rotating machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotational angle detection device having high detection accuracy of a rotational angle, and to provide a rotating machine. <P>SOLUTION: The rotational angle detection device includes a magnetic rotator having N pieces of magnetic poles (N is an integer of 2 more) and two Hall sensors for detecting a rotational angle of the magnetic rotator in accordance with magnetic fluxes applied from the magnetic rotator. The two Hall sensors are constituted by the Hall sensor for a radial direction of which the magnetic sensitive axis faces the radial direction of the magnetic rotator and the Hall sensor for a circumference direction of which the magnetic sensitive axis faces the circumference direction of the magnetic rotator. The Hall sensors are arranged such that an amplitude of a component of a magnetic flux density that is applied to the Hall sensor for a radial direction and an amplitude of a component of a magnetic flux density that is applied to the Hall sensor for a circumference direction are the same as each other. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a rotation angle detection device and a rotating machine that detect a rotation angle of a rotation shaft or the like using a hall sensor.

  In Patent Document 1, as shown in FIG. 4, a cylindrical permanent magnet 1 that is rotated on its axis (presumed to be a two-pole magnet from an arrow indicating a magnetic flux on the inner peripheral side) and two magnetosensitive elements. An angular position sensor composed of (Hall sensors) 2 and 3 and a processing circuit 4 is disclosed. The two magnetosensitive elements are generally arranged at the same point, and measure the radial component of the magnetic field and the circumferential component of the magnetic field to provide two sine wave signals.

  In Patent Document 2, as shown in FIG. 1, there is a rotation angle detection device including a dipole disk-shaped magnet 2 having a rotation axis, a first Hall element 3, and a second Hall element 4. It is disclosed. The magnetic detection surface of the second Hall element 4 is arranged substantially perpendicular to the magnetic detection surface of the first Hall element 3.

  In Patent Document 3, as shown in FIG. 5, a rotation composed of a rotating body having a penetrating shaft and a two-pole ring magnet 11, and a magnetic sensing unit installed at a space point above the magnet surface. An angle sensor is disclosed. The magnetic sensing section includes two Hall sensors (X-axis direction sensor 12x and Y-axis) that respectively sense two-axis components Bx and By that are parallel to the magnet surface of the magnetic flux density generated by the magnet and orthogonal to each other. A direction sensor 12y).

  In Patent Document 4, as shown in FIGS. 6 and 7, two magnets 2 (each of which is a dipole magnet) fixed to the magnetic shaft 1 with a predetermined gap in the axial direction are parallel. There is disclosed a rotation angle detection device constituted by the two magnets 2 arranged and one chip 10 arranged in a closed magnetic field by the magnetic shaft 1. In the one chip 10, the first magnetic sensor and the second magnetic sensor are tilted 90 degrees and are built in an L shape.

In Patent Document 5, as shown in FIG. 9, a magnetic encoder device including a rotating body 1 having a two-pole permanent magnet 2 and a magnetic field detection element 4 is disclosed. Wherein the magnetic field detection element 4 is provided with a circumferential magnetic sensing section 46 for detecting a magnetic flux density component B _r radial magnetic sensitivity surfaces 45 and the magnetic flux density components for detecting the B _theta, viewed from the direction of the permanent magnet rotation shaft, It is arranged so as to form a cross shape.

  In Patent Document 6, as shown in FIGS. 4 and 6, a disc-shaped two-pole magnet 400 supported by a rotating shaft 403, and magnetic sensors A and B (Hall elements) around the circumference of the magnet 400. ) Is disclosed. In one configuration, the magnetic sensor is shifted in the direction of the rotation axis, and in the other configuration, the magnetic sensor is shifted in the direction of the rotation axis and the surface thereof is inclined with respect to the rotation axis. When viewed in the circumferential direction of the magnetic field, the angle formed by the straight line 412 passing through the center O of the disk and the approximate center of the magnetic sensor A and the straight line 411 passing through the center O and the approximate center of the magnetic sensor B is a mechanical angle. 90 deg. It is arranged to be. Here, the mechanical angle refers to an angle of 360 degrees around the circumference of the disk. It is what.

International Publication No. 2007/057563 Pamphlet (Explanation of figure 4 on page 10, second paragraph, REVENDICATIONS 1., figure 4 on page 16, first paragraph) Japanese Patent Laying-Open No. 2005-326291 (FIGS. 1 and 7) JP 2007-040850 A (FIG. 5) JP 2006-047227 A (FIGS. 6 and 7) International Publication No. 1999/13296 Pamphlet (FIGS. 9 to 11) Japanese Patent Laid-Open No. 2003-075108 (FIGS. 4 and 6)

According to FIG. 4 of Patent Document 1, signals measured by the two magnetosensitive elements 2 and 3 are processed by the processing circuit 4.
However, in order to convert it into an electrical signal proportional to the angular position of the magnet, the processing circuit 4 performs decoding and normalization on the two elements. That is, normalization of output signals obtained from the two hall sensors is performed by the processing circuit 4. Therefore, it is not disclosed to normalize the output signal of the Hall sensor that measures the circumferential component of the magnetic field with respect to the output signal of the Hall sensor that measures the radial component of the magnetic field by the arrangement of the two Hall sensors. It cannot be said to be a configuration for detecting a rotation angle with higher accuracy.

According to Patent Document 2, the first Hall element 3 and the second Hall element 4 are arranged in one place, thereby reducing the mounting space and improving the mountability. It is explained that stable angular accuracy can be obtained by making the output deviation due to temperature change substantially equal.
However, in the circumferential direction of the magnet 2, the magnetic sensitive center of the first Hall element 3 and the magnetic sensitive center of the second Hall element 4 are shifted by a predetermined angle Δθ ₁ . Due to this shift, a change in the magnetic flux density component received by the magnetic sensitive center of the other Hall element causes a predetermined angle delay or advance with respect to the change of the magnetic flux density component received by the magnetic sensitive center of one Hall element. There is a problem that an error occurs in the rotation angle measured by the rotation angle detection device due to this shift. It cannot be said to be a configuration for detecting a rotation angle with higher accuracy.

FIG. 7 of Patent Document 2 discloses a rotation angle detection device in which first and second Hall elements 3a and 4a are arranged adjacent to each other inside one chip 8. However, sensitive磁中center of the two Hall elements are not changed that are shifted by a predetermined angle [Delta] [theta] ₂ in the circumferential direction of the magnet _{2 (Δθ 1> Δθ 2)} . Incorporating and incorporating two Hall elements in one chip in an orthogonal state has a problem that it takes more man-hours than using two chips incorporating one Hall element.

According to FIG. 5 of Patent Document 3, the X-axis direction sensor 12x and the Y-axis direction sensor 12y are assembled so as to form a cross when viewed from the axial direction. From this form, it is presumed that the two Hall sensors are facilitated, a notch is formed in each, and the notch is inserted into a cross-shaped sensor.
However, if it is formed in a cross shape, if the magnetic sensitive center of the X-axis direction sensor 12x is disposed at the center of the cross-shaped sensor, the magnetic sensitive center of the Y-axis direction sensor 12y is displaced from the center of the cross-shaped sensor. . That is, in the circumferential direction of the magnet, the magnetic sensitive centers of the two sensors deviate by a predetermined angle Δθ ₃ , and an error occurs in the rotation angle measured by the rotation angle detection device. It cannot be said to be a configuration for detecting a rotation angle with higher accuracy.

Referring to FIG. 6 and FIG. 7 of Patent Document 4, in the circumferential direction of the magnet 2, sensitive磁中heart sensitive磁中mind first magnetic sensor 3 and the second magnetic sensor 4 is a predetermined angle [Delta] [theta] ₄ shift. Therefore. There is a problem that an error occurs in the rotation angle measured by the rotation angle detection device. It cannot be said to be a configuration for detecting a rotation angle with higher accuracy.
Although the chip incorporating the first and second magnetic sensors (two Hall sensors) is tilted at the tilt angle α, the deviation of the output wave height caused by the magnetic effect exerted by the magnetic shaft is suppressed, and the wave heights are made uniform. The purpose is that. That is, it is not intended to improve the angular accuracy corresponding to the magnetic flux by one magnet. Further, when the chip incorporating the Hall sensor is tilted at the tilt angle α, the axis of rotation corresponds to the radial direction of the magnet 2. When tilting the magnetic sensitive surface of the Hall sensor, there is no disclosure of a configuration in which the axis of rotation is the circumferential direction of the magnet 2.

The description of FIG. 9B of Patent Document 5 states that “the detection sensitivity and the arrangement position of the radial direction magnetic sensing part 45 and the circumferential direction magnetic sensing part 46 of the magnetic field detection element 4 are slightly different, so that the output The amplitude values of V′θ and V′r are slightly different .... The amplifiers 54 and 55 shown in FIG. 10 are provided in the signal processing circuit 5, and the gain of the amplifier 54 is adjusted according to the amplitude ratio α. The output Vr is obtained from the output V′r and input to the angle calculation circuit 56 to obtain the angle signal θ ”.
Therefore, by arranging the two Hall sensors, the amplitude value of the output signal of the Hall sensor that measures the radial component of the magnetic field is made equal to the amplitude value of the output signal of the Hall sensor that measures the circumferential component of the magnetic field (that is, Normalize.) Is not disclosed. It cannot be said to be a configuration for detecting a rotation angle with higher accuracy.

  In Patent Document 6, the surfaces of the two Hall sensors are arranged in the same direction with respect to the circumferential direction or radial direction of the magnet. Therefore, by arranging the two Hall sensors, the amplitude value of the output signal of the Hall sensor that measures the radial component of the magnetic field is made equal to the amplitude value of the output signal of the Hall sensor that measures the circumferential component of the magnetic field (that is, Normalize.) Is not disclosed. It cannot be said to be a configuration for detecting a rotation angle with higher accuracy.

  Therefore, an object of the present invention is to provide a rotation angle detection device and a rotating machine with high detection accuracy of the rotation angle.

The rotation angle detection device of the present invention includes a magnet rotor having N pole pairs of magnetic poles (where N is an integer equal to or greater than 2) and a magnet rotor according to the magnetic flux applied from the magnet rotor. With two Hall sensors for detecting the rotation angle,
The two Hall sensors are a radial Hall sensor in which a magnetic sensitive axis is arranged in the radial direction of the magnet rotor, and a circumferential direction in which a magnetic sensitive axis is arranged in the circumferential direction of the magnet rotor. It consists of a hall sensor and
The radial hall sensor and the circumferential hall sensor are arranged so that the amplitude of the magnetic flux density component received by the radial hall sensor and the amplitude of the magnetic flux density component received by the circumferential hall sensor are the same. It is characterized by being.
Here, the “magnetic flux density component received by the sensor” is a magnetic flux density component that can be detected by the Hall sensor, and corresponds to a magnetic flux density component orthogonal to the magnetic sensitive surface of the Hall sensor.

Another rotation angle detection device according to the present invention includes a magnet rotor having N pole pairs of magnetic poles (where N is an integer of 2 or more), and magnet rotation according to the magnetic flux applied from the magnet rotor. Two Hall sensors for detecting the rotation angle of the child,
The two Hall sensors are a radial Hall sensor in which a magnetic sensitive axis is arranged in the radial direction of the magnet rotor, and a circumferential direction in which a magnetic sensitive axis is arranged in the circumferential direction of the magnet rotor. It consists of a hall sensor and
The radial hall sensor and the circumferential hall sensor are (2s ₁ −1) × 360 / (4N) deg. (Where s ₁ is a natural number including 0),
The radial hall sensor and the circumferential hall sensor are arranged so that the amplitude of the magnetic flux density component received by the radial hall sensor and the amplitude of the magnetic flux density component received by the circumferential hall sensor are the same. Has been
The rotation angle is detected by combining the outputs of the radial hall sensor and the circumferential hall sensor.

  The distance r between the magnetic pole outer peripheral surface of the magnet rotor and the magnetic sensing center of the hall sensor is preferably arranged such that r of the radial hall sensor is larger than r of the circumferential hall sensor. Here, the “magnetic pole outer peripheral surface” refers to the outer peripheral surface of the magnet portion.

About the distance h between the magnetosensitive center of the Hall sensor and the plane passing through the thickness center point of the magnet rotor and perpendicular to the rotation axis,
It is preferable that h of the radial hall sensor is arranged to be larger than h of the circumferential hall sensor.
Preferably, h in the circumferential hall sensor is zero. In the circumferential hall sensor, the higher the h, the smaller the amount of magnetic flux received on the magnetosensitive surface, so the sensor output becomes smaller. When the sensitivity of the hall sensor for radial direction and the hall sensor for circumferential direction is the same, the output of the hall sensor for circumferential direction is lowered to make the output and the amplitude of the hall sensor for radial direction the same. Therefore, as the circumferential hall sensor is shifted in the z-axis direction, the sensitivity of the entire system decreases and the output of the rotation angle detection device also decreases.

  The inclination χ of the magnetosensitive surface of the Hall sensor with respect to the rotation axis of the magnet rotor (where χ is in the range of 0 to 90 deg.) Is arranged so that χ ≠ 0 of the radial Hall sensor. It is preferable that

Another rotation angle detection device according to the present invention includes a magnet rotor having N pole pairs of magnetic poles (where N is an integer of 2 or more), and magnet rotation according to the magnetic flux applied from the magnet rotor. And four Hall sensors for detecting the rotation angle of the child,
The four Hall sensors have first and second radial Hall sensors arranged with the magnetic sensitive axes directed in the radial direction of the magnet rotor, and the magnetic sensitive axes directed in the circumferential direction of the magnet rotor. The first and second circumferential hall sensors are arranged in the manner described above.

Another rotation angle detection device according to the present invention includes a magnet rotor having N pole pairs of magnetic poles (where N is an integer of 2 or more), and magnet rotation according to the magnetic flux applied from the magnet rotor. And four Hall sensors for detecting the rotation angle of the child,
The four Hall sensors have first and second radial Hall sensors arranged with the magnetic sensitive axes directed in the radial direction of the magnet rotor, and the magnetic sensitive axes directed in the circumferential direction of the magnet rotor. And the first and second circumferential hall sensors arranged
The first radial hall sensor and the second circumferential hall sensor are (2s ₁ −1) × 360 / (4N) deg. In the circumferential direction of the magnet rotor. (Where s ₁ is a natural number including 0),
The second radial hall sensor and the first circumferential hall sensor are (2s ₂ −1) × 360 / (4N) deg. In the circumferential direction of the magnet rotor. (Where s ₂ is a natural number including 0),
Synthesizing outputs of the first radial hall sensor and the second circumferential hall sensor, and synthesizing outputs of the second radial hall sensor and the first circumferential hall sensor; Thus, the rotation angle is detected.

Further, the first and second radial hall sensors are (2s ₃ −1) × 360 / (4N) deg. It is preferable that s ₃ is provided so as to make an angle of (note that s ₃ is a natural number including 0).

The first radial hall sensor so that the amplitude of the magnetic flux density component received by the first radial hall sensor is the same as the amplitude of the magnetic flux density component received by the second circumferential hall sensor. And arranging the second circumferential hall sensor,
The second radial hall sensor so that the amplitude of the magnetic flux density component received by the second radial hall sensor is the same as the amplitude of the magnetic flux density component received by the first circumferential hall sensor. It is preferable to arrange the first circumferential hall sensor.

About the distance r between the magnetic pole outer peripheral surface of the magnet rotor and the magnetic sensing center of the Hall sensor,
The first radial hall sensor is arranged so that r thereof is larger than r of the second circumferential hall sensor,
It is preferable that the second radial hall sensor is arranged such that r of the second radial hall sensor is larger than r of the first circumferential hall sensor.

About the distance h between the magnetosensitive center of the Hall sensor and the plane passing through the thickness center point of the magnet rotor and perpendicular to the rotation axis,
The first radial hall sensor h is arranged to be larger than the second circumferential hall sensor h,
It is preferable that h of the second radial hall sensor is arranged to be larger than h of the first circumferential hall sensor.

About the inclination χ (where χ is in the range of 0 to 90 deg.) Of the magnetosensitive surface of the Hall sensor with respect to the rotation axis of the magnet rotor.
The first radial hall sensor is arranged so that χ ≠ 0,
It is preferable that the second radial hall sensor is arranged so that χ ≠ 0.

  Regarding the distance r between the magnetic pole outer peripheral surface of the magnet rotor and the magnetic sensing center of the hall sensor, r of the first radial hall sensor is equal to r of the second radial hall sensor, and the first It is desirable that r of the circumferential hall sensor is equal to r of the second circumferential hall sensor.

  With respect to the distance h between the magnetic sensing center of the Hall sensor and the plane passing through the thickness center point of the magnet rotor and perpendicular to the rotation axis, h of the first radial hall sensor is the second radial direction. It is desirable that h of the first circumferential hall sensor is equal to h of the second circumferential hall sensor.

  With respect to the inclination χ of the magnetosensitive surface of the Hall sensor with respect to the rotation axis of the magnet rotor (where χ is in the range of 0 to 90 deg.), The χ of the first radial Hall sensor is the second. It is desirable that χ of the radial hall sensor is equal to χ, and χ of the first circumferential hall sensor is equal to χ of the second circumferential hall sensor.

  Since the circumferential magnetic flux density is smaller than the radial magnetic flux density, it is desirable that the circumferential hall sensor be close to the magnet, and more preferably perpendicular to the magnetic field lines. Conversely, since the radial magnetic flux density is larger than the circumferential magnetic flux density, there is a degree of freedom in the arrangement of the radial hall sensors, and the radial hall sensors can be tilted away from each other or tilted without being perpendicular to the magnetic field lines. Can be arranged so that the same magnetic flux density can be obtained and the same output voltage can be obtained. There is also an advantage that the adjustment range can be narrowed and adjustment becomes easy.

  In this invention, the freedom degree of arrangement | positioning of a Hall sensor increases. In one radial direction, a circumferential magnetic flux can be arranged on the inner side and a radial magnetic flux can be arranged on the outer side. The circumferential direction can be placed on the rotating surface of the rotary magnet, and the radial direction can be moved in the axial direction from the circumferential direction sensor.

  In the present invention using four hall sensors, although the number of sensors is large, the sensor section (a pair of two hall sensors) is installed only in two places in the circumferential direction, so that attachment is easy. . If the magnetic sensing surfaces of the circumferential and radial Hall sensors are orthogonal to each other, the phase difference of 90 deg. Is substantially maintained, it is avoided that the angle error in the rotation angle detector increases after the calculation.

  A rotating machine according to the present invention includes the above-described rotation angle detection device.

  Here, outputting the rotation angle signal corresponding to the rotation angle means performing processing including arctangent calculation. Specifically, it is a process of performing an arctangent calculation digitally.

  ADVANTAGE OF THE INVENTION According to this invention, the rotation angle detection apparatus and rotary machine with a high rotation angle detection accuracy can be provided.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, this invention is not necessarily limited by these embodiment.

(Embodiment 1)
FIG. 1A schematically shows a rotation angle detection device in which a first Hall IC 12a and a second Hall IC 12b are arranged on the outer periphery of a ring magnet 11 magnetized to 12 poles. FIG. 4A is a front view, and FIG. 4B is a cross-sectional view, showing only the positional relationship between components. The first Hall IC 12a is located at a position where the phase in the circumferential direction is the same as that of the second Hall IC 12b, and r is larger than 12a in the radial direction. The magnetic sensitive axis B01 of the second Hall IC 12b is along the circumferential direction of the ring magnet, and the magnetic sensitive axis A01 of the first Hall IC 12a is arranged along the radial direction of the ring magnet. When the ring magnet rotates, each is arranged such that the amplitude of the magnetic flux density component received by the first Hall IC 12a is the same as the amplitude of the magnetic flux density component received by the second Hall IC 12b. As shown in the circuit diagram of (c), the output of each Hall IC is input to the AD converter 27 as a Va signal and a Vb signal, and the AD-converted signal passes through the angle calculator 28 to be magnetized. A detection angle indicating the rotation angle of the rotor is obtained. In addition, display of the drive voltage, GND terminal, etc. which drive each Hall IC is abbreviate | omitted. This is represented by a cylindrical coordinate system in which the center of the ring magnet 11 of the magnet rotor is the origin and the rotation axis is the Z axis. The diameter of the ring magnet is 2r ₀ , the thickness is t (thickness is the dimension in the rotation axis direction), the distance from the Z axis to the center of the Hall IC 12b (magnetic center) is r ₀ + r ₁ , and the distance from the Z axis to the Hall IC 12a The distance to the center (magnetic center) is r ₀ + r ₂ . Using this configuration, the error in the detected angle is ± 1 deg. Got.

(Embodiment 2)
2 shows that the position of the first Hall IC 12a in FIG. 1 is 360 × 3 deg. (Mechanical angle is 180 deg.) An embodiment in which the phase is shifted and moved is shown. 2A is a front view, and FIG. 2B is a cross-sectional view. The first Hall IC 12a operates equivalent to the case of FIG. The display of the A-D converter and the like is omitted. However, each Hall IC is arranged so as to sandwich the ring magnet, and even if the shaft of the magnet rotor is displaced at the time of rotation, the influence of the deviation that one Hall IC is slightly separated from the ring magnet, The effect of the deviation of the other Hall IC slightly approaching the ring magnet is offset by the angle calculator, and even if a shaft misalignment occurs compared to the configuration of FIG. Angular errors can be suppressed. In the state where the shaft is not misaligned, using this configuration, the error of the detected angle is ± 1 deg. Got.

(Reference form 1)
An outline of the arrangement of the Hall ICs in the rotation angle detection device of the reference form is shown in the front view of FIG. Two Hall ICs 41 and 44 are arranged along the circumferential direction of the ring magnet 11 of the magnet rotor (the rotation direction of the ring magnet 11). The Hall IC 41 directs the magnetic sensitive axis (direction in which the magnetic flux is detected) to the center of the ring magnet 11, and the other Hall IC 44 directs the magnetic sensitive axis to the circumferential direction of the ring magnet 11. The distance between Hall ICs is 90 + 180 deg. And The distance r between the ring magnet surface and the magnetic sensitive center of the Hall IC satisfies r / λ = 1/12. The outputs of the Hall ICs 41 and 44 are input to the AD converter, the obtained conversion output is input to the angle calculator, and the detection angle of the rotation angle detector is obtained as the output. The detection angle error is ± 4 deg. Got.

(Function)
A magnet rotor having 2N poles in the rotation direction will be described. This magnet rotor may be rephrased as having N pole pairs of magnets, and has N times of axial symmetry. A mechanical angle φ of a certain reference angle is expressed by [Equation 1] by an electrical angle θ.

  Assuming that the magnetic flux density coming out of this magnet rotor is a magnet rotor that is infinitely long in the axial direction for simplification (that is, it is assumed that the magnetic flux density is uniformly distributed in the axial direction) ), The magnetic flux density in the space generated from the magnet rotor is considered as a vector, and the magnetic flux density component Br in the radial direction and the magnetic flux density component Bθ in the rotational direction are represented by the measurement position (r, φ) expressed in the cylindrical coordinate system. The function can be approximated by the following [Equation 2] function.

Further, when the fundamental wave component is not zero, that is, when A ₁ is not zero, r becomes large to some extent, and when the third-order or higher harmonic is smaller than the fundamental wave represented by A ₁ [Equation 3 ] Can be simplified.

This means that the direction of the magnetic flux changes by θ when the magnet rotor moves by an angle θ with respect to the measurement point. That is, the rotation angle of the magnet rotor can be measured by detecting the direction of the magnetic flux regardless of the magnitude of the magnetic flux density. While in the above formula and infinitely long above were the same of A ₁ the magnitude of the amplitude of the sin signal and the cos signal, generally when the shaft is a finite length and the like, applied to the term of the term and the sin of cos The magnitude of the coefficient may be different. When the magnitudes of the coefficients are different, it is necessary to adjust the amplitude according to the conditions.

  When the same Hall sensor is used to obtain sin and cos signals at the same time as described above, 90 deg. The phase difference is required. Many combinations are possible to obtain this phase difference. In other words, since the Hall sensor has anisotropy in one direction (that is, a magnetosensitive axis), an angle ξ formed by the Hall sensor itself with respect to a line drawn in the normal direction from the center of the rotor is arbitrarily set. Is possible, but the angle ξ is 0 deg. , ± 90 deg, ± 180 deg. It is preferable that it is either. This ξ is called a rotation angle.

  When fixing the position of the hall sensor, the first hall sensor is set to 0 (zero) deg. It is assumed that the second hall sensor is disposed at the position θ in terms of electrical angle at the position. This θ is temporarily called a revolution angle. Revolution angle θ = 90 deg. When the second hall sensor is disposed at the position, it is possible to obtain a signal having a relationship between sin θ and cos θ by setting the rotation angle ξ of the first hall sensor and the second hall sensor to the same angle. It becomes. Further, when the first Hall sensor is used as a reference, that is, the revolution angle of the first Hall sensor is 0 deg. And the rotation angle is 0 deg. In this case, the second hall sensor has a revolution angle θ = 45 deg. And the rotation angle ξ = −45 deg. It is possible to obtain a similar signal, and the revolution angle θ = 180 deg. And the rotation angle ξ = 90 deg. It is also possible to obtain a similar signal.

  Further, the revolution angle θ of the two Hall sensors is 0 deg. And the rotation angle ξ = 0 deg. Of the first Hall sensor. And the rotation angle of the second sensor element ξ = 90 deg. It is possible to obtain a similar signal even if two hall sensors are provided at the same location. When these are further expanded, the revolution angle difference between the first Hall sensor and the second Hall sensor is Δθ, and the rotation angle difference between the first Hall sensor and the second Hall sensor is Δξ. In addition, any combination of [Delta] [theta] and [Delta] [xi] having the relationship of [Equation 4] may be used.

  Further, since the magnet rotor is composed of a multi-pole pair, the second Hall sensor does not stop at the above-mentioned angle in terms of electrical angle but has moved an angle in units of one cycle (electric angle is set to 360 deg. × n). It is possible to obtain a similar signal even if it is installed at a corresponding location, and the integer n may be plus or minus. In other words, any combination of θ and ξ that satisfies the relationship of [Equation 5] may be used (where n is an arbitrary integer). This is the most generalized formula.

(Applicable magnetic sensor)
As a magnetic sensor for realizing the above magnetic sensor, there is a Hall sensor having a Hall element. The Hall element is a sensor element that changes its output voltage value by detecting the “magnitude” of the magnetic flux density, and normally detects the magnetic flux density component applied perpendicularly to the surface of the sensor element in a one-dimensional manner. (This direction corresponds to the magnetosensitive axis.) The flat surface of the Hall sensor (the magnetic sensitive portion: corresponding to the widest surface of the molded surface) is parallel to the surface of the sensor element (magnetic sensitive surface) that detects the change in magnetic flux density, and the magnetic sensitive axis. Is orthogonal. The center of the magnetic sensitive surface is referred to as the magnetic sensitive center. More specifically, the output of the Hall sensor is proportional to the magnetically sensitive axial direction component of the magnetic flux density in the magnetically sensitive portion of the Hall sensor. In the present invention, the entire sensor system is configured by paying attention to the voltage change when the Hall sensor is placed in the rotating magnetic field. Hall sensor that changes the voltage of cos α (α is the angle formed by the magnetic flux with respect to the reference direction) relative to the rotating magnetic field, Hall sensor that changes the voltage of the opposite sign (−cos α), or a combination of elements Is used. By applying a Hall sensor that outputs a voltage proportional to cos α when a DC voltage is applied, the following Vout is output as [Equation 6]. In Equation 6, δ is the rate of change of the output voltage with respect to the applied magnetic flux density Bin.

  In general, a Hall sensor having a Hall element is placed with its magnetosensitive axis directed toward the magnet rotor, and when a plurality of arrangements are made, it is placed at a predetermined position with an electrical angle (the revolution angle θ described above). ), Without changing the rotation angle ξ. Since the hall sensor must be installed only at spatially different positions, when the hall sensor is used as a magnetic sensor, its location is also limited, but in the present invention, this ξ can be changed. Even if they are arranged at the same mechanical angle, they can have different phase differences.

(Reduction of harmonic components by multiple magnetic sensors)
In the above description of the operation, it is assumed that when a magnet rotor is ideally rotated, a magnetic flux without sin or cos harmonics is generated temporally and spatially. , Harmonic components (harmonic distortion) A ₃ , A ₅ ,... Are not limited to zero. Rather, it is more common to assume that harmonic components are present. If expressed simply, it is expressed as Equation 7.

  That is, the ratio of the harmonic components that are distortion components is equal to each of the fundamental waves of Br and Bθ, and the cos component and the sin component are mainly used, respectively. In order to reduce this harmonic component, a method of arranging a plurality of magnetic sensors and greatly reducing only the harmonic component was invented.

(Reason why the angle error is reduced by changing the number of magnetic sensors from 2 to 4)
When there are four magnetic sensors, the r direction (radial direction) component tends to be a trapezoidal waveform and the θ direction (rotation direction) component tends to be a triangular wave when the magnetic flux coming out of the rotor is detected. The harmonics of have an antiphase relationship. The first Hall sensor has an electrical angle (revolution angle) of 90 deg. So that the r direction component of the magnetic flux density is detected, and the second Hall sensor detects the θ direction component of the magnetic flux density. Rotation angle -90 deg. Place with. At that time, the phases of the fundamental waves output from the respective hall sensors can be made to coincide with each other, and in this case, the main harmonics output from the respective hall sensors have an opposite phase relationship. Specifically, the first hall sensor is set to θ = 0 deg. ξ = 0 deg. And the second Hall sensor is θ = 90 deg. ξ = 0 deg. And the third Hall sensor is θ = 180 deg. ξ = 90 deg. And the fourth Hall sensor is θ = 270 deg. ξ = −90 deg. In this case, the outputs from the hall sensors are expressed as Vout ₁ to Vout ₄ .

  By using this relationship, by combining the positional relationship, the fundamental waves from the two Hall sensors are added together, and at the same time, the main third-order harmonic components are added and reduced so as to be in antiphase, and the amplitudes are equal, And 90 deg. Two signals having different phases can be obtained, and as a result, the angle error can be reduced. Here, since the positive and negative signs of each output correspond to the front and back of the surface of the Hall sensor, they can be appropriately arranged so that the mathematical formula is established.

  In Expression 8, although the output amplitude is different due to the coefficient Km which is not generally 1, the same amplitude can always be obtained by combining the outputs of the two Hall sensors in this way. The first and second Hall sensors, the third Hall sensor, and the fourth Hall sensor are respectively the same distance from the center of the magnet rotor and the same angular difference in the circumferential direction with respect to the magnet rotor (= electrically 90 degrees different). If it arrange | positions so that it may become, it will satisfy conditions. The placement of the Hall sensor becomes easy.

While the ratio of the third harmonic to the fundamental wave in Equation 8 is A ₃ / A ₁ ,
That in Equation 9 is (Km−1) / (Km + 1) × A ₃ / A ₁ . Therefore, by increasing the number of Hall sensors from two to four, the third harmonic, which is the largest cause of the rotation angle error obtained from the arc tangent calculation, can be reduced to (Km−1) / (Km + 1). it can.

  When another set of Hall ICs was added in the configuration of Reference Mode 1 (FIG. 3), Km was about 1.4 to 2. That is, as indicated by the dotted line, an electrical angle of 90 de. Hall IC 42 is provided at a position apart from the Hall IC 44, and an electrical angle of −90 deg. A Hall IC 43 is provided at a distant position. The previous set of outputs and the added set of outputs are added and averaged by an operational amplifier, and a detection angle is obtained using an A-D converter and an angle calculator. Therefore, by increasing the number of hall sensors from two to four, the waveform distortion, that is, the angle error can be reduced from 30% to about 10% in the case of two hall sensors. Further, if the output amplitudes from the four Hall sensors are adjusted, the third-order harmonic distortion can be completely canceled if the configuration shown in FIGS. The error can be further suppressed. The cause of the angular error due to waveform distortion shifts from the third-order distortion to the fifth-order distortion, which is a smaller value.

  As a method of adjusting the output amplitude, the inventors have arranged a circumferential hall sensor at a position where r is small and a radial hall sensor where r is large on a track orbiting the magnet. Was invented. By reducing the effective magnetic flux density received by the other Hall sensor relative to the effective magnetic flux density received by one Hall sensor, the amplitudes of the output signals relating to both Hall sensors can be made uniform. In addition, the circumferential hall sensor can be arranged on the rotating surface of the magnet rotor, and the radial hall sensor can be moved to a position separated in the axial direction from the circumferential hall sensor. It can be seen that the degree of freedom of arrangement of the hall sensors is large. Since adjustment is possible by arrangement, it is not necessary to add an adjustment circuit.

  FIG. 4 is a graph obtained by measuring the relationship between the rotation angle of the magnet and the mechanical angle error for the configurations of the third embodiment (FIG. 12) and the second embodiment (FIG. 2). The thick line corresponds to Embodiment 3 with 4 sensors, and the thin line corresponds to Embodiment 2 with 2 sensors. In the configuration of the second embodiment, the detection angle error is ± 1 deg. Got. In the configuration of the third embodiment, the error of the detection angle is ± 0.4 deg. Got.

  When the hall sensors are oriented in the same direction with respect to the rotation axis as in the prior art, all hall sensors detect the magnetic flux density component in the radial direction, so the number of hall sensors is increased from two to four. However, the above effect does not appear. On the other hand, when four Hall sensors are arranged almost symmetrically with respect to the rotation axis, there is a feature that an increase in rotation angle error can be suppressed with respect to eccentricity (variation) of the rotation axis. In the present invention, the Hall sensor cannot be completely axisymmetrically arranged, and thus cannot be completely suppressed. However, one of the Hall sensors that obtains the in-phase output is installed at a location closest to the other axially symmetric position. (In the case of N = 8), it was confirmed that it can be suppressed to about 1/10 without inferiority.

  When the magnet rotor is, for example, 12 poles, the Hall IC 12b is arranged at a position different from the Hall IC 12a in the circumferential direction by a mechanical angle φ (φ = 15 deg.), And therefore there is a phase difference of the electrical angle θ ( θ = 90 deg.). When one receives the magnetic flux along the circumferential direction of the magnet rotor, the other receives the magnetic flux delayed by θ. By increasing the number of poles in this way, the φ with respect to θ is reduced, and a set of Hall ICs can be accommodated in a narrow area and reduced in size.

(Reduction of rotation angle error due to the number of poles)
When the maximum detection angle error is represented by a mechanical angle, the electrical angle error decreases according to the number of magnetic poles. For this reason, the present invention using a magnet rotor with a large number of magnetic poles has high resolution and can further reduce detection errors. In the case of a 12-pole magnet rotor, the rotational angle error is reduced to one-sixth of the mechanical angle compared to the case of using a 2-pole magnet rotor. When using a multi-pole (4 poles or more) ring magnet and incorporating a yoke on the inner periphery of the ring, the magnetic flux density applied to the Hall sensor can be increased compared to the case without a yoke, and the rotation angle detection device Contributes to improved output.
When the number of pole pairs of the magnet rotor is the same as the number of pole pairs of the motor, high-precision motor control is facilitated. Moreover, it can replace with a magnet rotor and a rotation angle can also be calculated | required using the magnet of a motor. Contributes to weight reduction and miniaturization.
Since the multipole magnet (4 poles or more) has less magnetic flux leaking outside than the dipole magnet, the magnetic influence on the outside is small.
The rotation period of the magnetic flux received by the Hall sensor is 1 / N times (N is an integer of 2 or more), and the resolution is higher than the mechanical rotation period of the magnet rotor. The above rotation angle detection device may be provided in a rotating machine.

5A and 5B are diagrams for explaining the rotation angle detection device according to FIG. 1 in more detail, in which FIG. 5A is a front view, and FIG. 5B is a side view (a lower half is a partial cross-sectional view). The rotation angle detection device shown in FIG. 5A includes a magnet rotor 1, a magnetic sensor unit 2, and a housing 3 to which the magnetic sensor unit is fixed. Hall ICs 12a and 12b (a Hall element and an operational amplifier are integrated). The rotation angle of the ring magnet 1a is detected by a hall sensor). The Hall IC in FIG. 5 is arranged such that the magnetic sensing axis of the Hall IC is parallel to the direction in which the lines of magnetic force are directed (corresponding to the radial direction when viewed from the center of the magnet rotor), and the magnetic sensitivity of the Hall IC. Some are arranged with the axis vertical. The relationship with this magnetic flux changes as the magnet rotates. As shown in FIG. 5B, the terminals of the Hall IC are fixed to the circuit board 2c. Further, the signals of the Hall ICs 12a and 12b are input to the A / D converter, and both of the obtained outputs are input to the angle calculator, and the value of the detected angle is obtained as the final output. The rotation angle is detected by using multiple magnet rotors and bringing the magnetic sensor arrangement close to each other. The same components are used in the other embodiments of the present invention except for the number and arrangement of Hall ICs (that is, the magnetic sensor unit).

  The magnet rotor 1 supports a ring-shaped permanent magnet 1a having an outer peripheral shape connecting a plurality of arcs, a soft magnetic ring 1b integrally formed on the inner peripheral side of the ring-shaped permanent magnet, and the soft magnetic ring The nonmagnetic ring-shaped adapter 1c is provided. The magnetic sensor unit 2 includes a plate-like circuit board 2c having a concave surface facing the magnet rotor 1, a pair of Hall ICs 12a and 12b fixed to the surface of the circuit board 2c, and the Hall IC and circuit. A cable 2d and a connector 2e for electrically connecting a control circuit or an output processing circuit to the circuit board 2c, and a nonmagnetic cover 2f covering the Hall IC. The housing 3 is provided with a U-shaped angle 3a and a bolt 3c for fixing the circuit board 2c so that the Hall ICs 12a and 12b face the magnet rotor 1 at a predetermined interval.

  In order to use the rotation angle detection device of FIG. 5, the housing 3 in which the magnetic sensor unit 2 is installed is fixed to the machine tool body (using the bolting holes 3b), and the magnet rotor 1 is attached to the rotation shaft of the machine tool. It is fixed so as to be coaxial (using the bolting hole 1d) (the machine tool is not shown in FIG. 5). As shown in FIG. 5 (a), when the rotating shaft of the machine tool is driven in a state where the magnet rotor 1 and the magnetic sensor unit 2 are opposed to each other, the configuration to which the rotation angle detection device of the first embodiment is applied is high. The rotation angle can be detected with accuracy.

Here, the magnet rotor 1 includes a ring-shaped permanent magnet 1a formed by molding NdFeB-based magnetic powder and a binder, a soft magnetic ring 1b formed by molding soft iron powder and a binder, and the soft magnetic ring is attached to a rotating shaft. For this purpose, the adapter 1c made of S45C is used. The Hall ICs 12a and 12b are 15 deg. It is fixed to the circuit board 2c so as to make an angle (mechanical angle: φ). The housing 3 and the U-shaped angle 3a are also made of nonmagnetic SUS316.
Radius of circumscribed circle (illustrated by dotted line) of magnet rotor 1: 40 mm
The distance r ₁ between the circumscribed circle of the magnet rotor 1 (illustrated by a dotted line) and the magnetic sensing center of the Hall IC 12b: 3.5 mm
The distance r ₂ between the circumscribed circle of the magnet rotor 1 (illustrated by a dotted line) and the magnetic sensing center of the Hall IC 12a: 5.5 mm
Magnet rotor 1 thickness t: 25 mm
Thickness T of housing 3: 2 mm (A 2 mm thick plate is punched out and formed with a diaphragm)
When the distance r was changed, it could be used without any problem even when r = 10 mm. Further, even when the thickness t of the magnet rotor 1 was 5 mm, it could be used without any problem.

(Embodiment 3)
6 reduces the distance between the magnetic sensing center of the first Hall IC 12a and the ring magnet 11 to r ₁ in FIG. 2, and the distance h in the axial direction (Z-axis direction) of the ring magnet 11 from the magnetic sensing center. Fig. 5 shows an embodiment translated. 6A is a front view, and FIG. 6B is a cross-sectional view. This distance h is such that when the ring magnet rotates, the amplitude of the magnetic flux density component received by the first Hall IC 12a is the same as the amplitude of the magnetic flux density component received by the second Hall IC 12b.

(Embodiment 4)
7 reduces the distance between the magnetic sensing center of the first Hall IC 12a and the ring magnet 11 to r ₁ in FIG. 2, and sets the magnetic sensing surface of the Hall IC 12a to an angle χ with respect to the axial direction of the ring magnet 11. Fig. 3 shows a tilted embodiment. FIG. 7A is a front view, and FIG. 7B is a cross-sectional view. This sensor inclination angle χ corresponds to an angle at which the amplitude of the magnetic flux density component received by the first Hall IC 12a is the same as the amplitude of the magnetic flux density component received by the second Hall IC 12b when the ring magnet rotates.

(Embodiments 5 to 10)
FIG. 8 shows a plurality of embodiments in which the positions of the first Hall IC 12a and the second Hall IC 12b and the magnet rotor in FIG. 1 are changed. 8A to 8F are cross-sectional views for each embodiment. In any case, the amplitude of the magnetic flux density component received by the first Hall IC 12a is arranged to be the same as the amplitude of the magnetic flux density component received by the second Hall IC 12b. In (a), (b), (d), and (e), the ring magnet 11 is replaced with a disk magnet 21. In (c) and (f), the ring magnet 11 is not changed.

(Embodiments 11 to 13)
FIG. 9 shows a plurality of embodiments in which the positions of the first Hall IC 12a and the second Hall IC 12b and the magnet rotor are changed in FIG. Each of FIGS. 9G to 9I is a cross-sectional view for each embodiment. In any case, the amplitude of the magnetic flux density component received by the first Hall IC 12a is arranged to be the same as the amplitude of the magnetic flux density component received by the second Hall IC 12b. In (a), (b), (d), and (e), the ring magnet 11 is replaced with a disk magnet 21.

(Embodiment 14)
10 adds another set of the first and second Hall ICs in FIG. 1, and the addition position is 360 × 3 + 90 deg. An embodiment in which the phase is changed is shown. 10A is a front view, FIG. 10B is a cross-sectional view, and FIG. 10C is a graph showing the relationship between the sensor output and the rotation angle of each set of Hall ICs. The first and second Hall ICs 13a and 13b to be added are perpendicular to the magnetosensitive axes A02 and B02. When this configuration is used, the detection angle error is ± 0.6 deg. Got. When the fine adjustment is further advanced, the amplitude of each waveform in (c) becomes the same, and the angle error is almost eliminated.

(Embodiment 15)
FIG. 11 shows an embodiment in which the circumferential arrangement of the Hall ICs in FIG. 10 is changed. As shown in the front view of (a), the Hall IC 12a and the Hall IC 13a are moved clockwise to a position shifted in phase by an electrical angle of 360 degrees. However, the magnetic sensing centers of the Hall IC 12a and the Hall IC 13a are translated in the Z-axis direction by the amount close to the ring magnet. By this adjustment, when the ring magnet rotates, each is arranged such that the amplitude of the magnetic flux density component received by the first Hall IC 12a is the same as the amplitude of the magnetic flux density component received by the second Hall IC 12b.

(Embodiment 16)
FIG. 12 shows another addition of the first and second Hall ICs in FIG. 6, and the added position is 360 + 90 deg. An embodiment in which the phase is changed is shown.

(Embodiment 17)
FIG. 13 shows another addition of the first and second Hall ICs in FIG. 7 and the addition position is 360 + 90 deg. An embodiment in which the phase is changed is shown.

(Reference form 2)
FIG. 14 shows a reference form in which the position and angle ξ of the Hall IC in FIG. 1 are changed. In FIG. 14A, the position and the angle ξ of the Hall IC 12 are not changed and are set to the Hall IC 120a, but the Hall IC 12b is moved to be the Hall IC 120b. As a result, the line connecting the rotation center of the ring magnet and the magnetic sensing center of the Hall IC 120a and the line connecting the rotation center of the ring magnet and the magnetic sensing center of the Hall IC 120b form an angle Δθ. Although the magnetic sensitive axes A01 and B01 are orthogonal to each other, the phase of the output of the Hall IC is shifted by this Δθ, so that an angle error is added to the detection angle of the rotation angle detection device, and it is difficult to increase the detection accuracy.

  FIG. 14B shows that the Hall IC 120b shown in FIG. 14A is tilted to correct the deviation of the angle ξ and maintains the orthogonal relationship between the magnetic sensitive axes A01 and B01. Therefore, as in FIG. 5A, an angle error is added to the detection angle of the rotation angle detection device, and it is difficult to increase the detection accuracy. (C) of FIG. 14 is obtained by correcting the ξ of the Hall IC 120a in FIG. 14 (b) and directing the magnetosensitive axis toward the rotation center of the ring magnet. However, there is no change in the phase difference of Δθ between the two Hall ICs, and since Δθ is not an integer multiple of 90 deg, the problem of angular error remains.

(Surface magnetic flux density distribution)
FIG. 15 shows the positional relationship between the magnetic flux of the magnet rotor (four or more poles) and the Hall sensor in the present invention. FIG. 2A is a front view, and FIG. In FIG. 15A, the direction of magnetization in each magnetic pole of the ring magnet 11a of the magnet rotor is represented by a straight thick arrow, and the magnetic flux generated from the magnetic pole surface is represented by a curved thick arrow. The Hall IC 12 receives a magnetic flux in the X-axis direction. λ corresponds to one wavelength of a sine signal when measuring the surface magnetic flux density distribution (360 deg. in electrical angle), and in the ring magnet 11a, corresponds to the circumferential length of a pair of magnetic pole surfaces. r ₁ is when viewed along the radial direction of the ring magnet 11a, a distance between the center of the sensitive surface of the Hall IC 12 (sensitive磁中Center) and the surface of the ring magnet 11a (outer peripheral surface). At this time, the Hall IC 12 receives a magnetic flux in the X-axis direction. Ring magnet 11a is electrically angled in the circumferential direction η = 90 deg. When it is rotated only, the Hall IC 12 receives a magnetic flux in the Y-axis direction (there is no output because it is a magnetic flux density component orthogonal to the magnetic sensitive axis). The Z-axis is an axis that passes through the center o of the hole of the ring magnet 11a and is orthogonal to the rotation plane of the magnet, and corresponds to the rotation axis of the magnet rotor. θ _m is a mechanical angle representing the mechanical rotation of the magnet rotor. When the Hall IC 12 that is on the dotted line op connecting the rotation center o and the point p of the magnet rotor and is centered at a distance r from the surface of the magnet rotor 1a is used as a reference, the Hall IC 12r is On the other hand, it can be said that the electrical angle is different by η in the circumferential direction. η is called the revolution angle. An angle ξ formed by a dotted line connecting the center of the Hall IC 12r and the rotation center o of the magnet rotor and the magnetosensitive axis of the Hall IC 12r is referred to as a rotation angle. The radial Hall sensor is ξ = 0 deg. It is. The circumferential hall sensor is ξ = 90 deg. It is. θm is a mechanical angle representing the mechanical rotation of the magnet rotor.

  FIG. 15B shows the arrangement of three Hall ICs 12 and Hall ICs 12 '. In the Hall IC 12, the center of the magnetosensitive surface is arranged on the XY plane with Z = 0, and the magnetosensitive surface is tilted by χ with respect to the XY plane. The Hall IC 12 'is located at the sensor arrangement angle φ' and tilted by χ 'with respect to the XY plane. The center of the Hall IC 12 'is h' away from the plane passing through the center point of the thickness of the ring magnet 11a and perpendicular to the rotation axis in the Z-axis direction. At the position of the Hall IC 12 ', the direction of the magnetic flux is inclined by ε' from the X axis. The center of the Hall IC 12 ″ is on the axis of rotation of the ring magnet of the magnet rotor (φ ″ = 90 deg.), And the magnetosensitive surface is parallel to the XY plane (χ ″ = 180 deg. And ε ′. '= 180 deg.). The thickness t of the ring magnet is a dimension in the Z-axis direction. The thickness center point of the magnet is a point where the center of the XY cross section of the magnet intersects the center of the Z axis cross section, and corresponds to the origin of the XYZ axes. A shaft serving as a rotating shaft can be fixed to the hole of the ring magnet.

  FIG. 16 is a schematic view for explaining the rotating machine of the present invention. The Hall IC 82b has the surface of the Hall IC 82a (the surface perpendicular to the magnetic sensing axis of the Hall IC) along the circumferential direction (θ direction) of the magnet rotor 71c (the surface of the Hall IC (that) This is equivalent to a configuration in which the surface is changed to a direction perpendicular to the surface perpendicular to the magnetic sensitive axis and is disposed at a position shifted in the circumferential direction.

  As shown in FIG. 16, this rotating machine is a motor. In a frame 73c, a permanent magnet rotor 71a having a shaft 71b as a central axis, and a stator with a stator coil 73b fixed to the inner peripheral surface of the frame 73c. 73a is installed. The shaft 71b was rotatably fixed to the frame 73c via a bearing (not shown). Further, the magnet rotor 71c is provided on the shaft 71b, and the Hall IC 82a is installed on the frame 73c via the support portion 72n. The rotating machine also includes a radial Hall IC 82c (not shown) that is the same as the Hall IC 82a and a circumferential Hall IC 82d (not shown) that is the same as the Hall IC 82b.

  The rotating magnetic field of the magnet rotor 71c was detected by the Hall IC 82a and the Hall IC 82b, their outputs were input to the arithmetic circuit 72m, and the two outputs were subjected to arctangent calculation to obtain the rotation angle of the magnet rotor 71c. The axis of magnetic rotation in the magnetization direction is indicated by a chain line in the figure.

  When the configuration of the first embodiment is applied to a motor, the Hall IC whose magnetosensitive axis faces the radial direction of the magnet rotor is arranged to face the magnet rotor as in the Hall IC 82a of FIG. In the configuration of the first embodiment, the Hall IC in which the magnetosensitive axis faces the circumferential direction of the magnet rotor is arranged so as to be different from the Hall IC by 90 ° as in the Hall IC 82b of FIG.

  FIG. 17 is a schematic diagram for explaining another rotating machine of the present invention, which is an application example in which the configuration of FIG. 16 is modified. In FIG. 17, the rotor 71a and the magnet rotor 71c are replaced with the rotor 71e. The rotating magnetic field of the magnet rotor 71e is detected by the Hall IC 82a and the Hall IC 82b, processed by an arithmetic circuit, and rotated by the magnet rotor. Detect the angle.

It is the schematic which shows the rotation angle detection apparatus of this invention. It is the schematic which shows the other rotation angle detection apparatus of this invention. It is the schematic which shows the rotation angle detection apparatus of a reference form. It is a graph which shows the relationship between the rotation angle of a magnet, and a mechanical angle error. It is a figure explaining the rotation angle detection apparatus concerning FIG. 1 in detail. It is the schematic which shows the other rotation angle detection apparatus of this invention. It is the schematic which shows the other rotation angle detection apparatus of this invention. It is the schematic which shows the other rotation angle detection apparatus of this invention. It is the schematic which shows the other rotation angle detection apparatus of this invention. It is the schematic which shows the other rotation angle detection apparatus of this invention. It is the schematic which shows the other rotation angle detection apparatus of this invention. It is the schematic which shows the other rotation angle detection apparatus of this invention. It is the schematic which shows the other rotation angle detection apparatus of this invention. It is the schematic which shows the other rotation angle detection apparatus of a reference form. It is the schematic explaining the positional relationship of the magnetic flux of a magnet rotor, and a Hall sensor. It is the schematic explaining the rotary machine of this invention. It is the schematic explaining the other rotary machine of this invention.

Explanation of symbols

1: magnet rotor, 1a: ring-shaped permanent magnet, 1b: soft magnetic ring, 1c: adapter,
1d: Bolt fixing hole,
2: Magnetic sensor part,
2c: circuit board, 2d: cable, 2e: connector, 2f: non-magnetic cover,
3: Housing, 3a: U-shaped angle, 3b: Bolt fixing hole, 3c: Bolt,
11: Ring magnet, 11a: Ring magnet,
12, 12 ′, 12 ″: Hall IC,
12a, 12b, 12r: Hall IC,
13a, 13b: Hall IC,
21: Multipolar magnet,
27: AD converter, 28: Angle calculator,
41, 42, 43, 44: Hall IC,
71a: rotor, 71b: shaft, 71c: magnet rotor, 71e: rotor,
72m: arithmetic circuit, 72n: support part,
73a: Stator, 73b: Coil for stator, 73c: Frame,
82a: Hall IC, 82b: Hall IC,
120a, 120b: Hall IC

Claims (16)

A magnet rotor having N pole pairs of magnetic poles (where N is an integer of 2 or more) and two for detecting the rotation angle of the magnet rotor according to the magnetic flux applied from the magnet rotor With a hall sensor
The two Hall sensors are a radial Hall sensor in which a magnetic sensitive axis is arranged in the radial direction of the magnet rotor, and a circumferential direction in which a magnetic sensitive axis is arranged in the circumferential direction of the magnet rotor. It consists of a hall sensor and
The radial hall sensor and the circumferential hall sensor are arranged so that the amplitude of the magnetic flux density component received by the radial hall sensor and the amplitude of the magnetic flux density component received by the circumferential hall sensor are the same. A rotation angle detection device characterized by being provided. A magnet rotor having N pole pairs of magnetic poles (where N is an integer of 2 or more) and two for detecting the rotation angle of the magnet rotor according to the magnetic flux applied from the magnet rotor With a hall sensor
The two Hall sensors are a radial Hall sensor in which a magnetic sensitive axis is arranged in the radial direction of the magnet rotor, and a circumferential direction in which a magnetic sensitive axis is arranged in the circumferential direction of the magnet rotor. It consists of a hall sensor and
The radial hall sensor and the circumferential hall sensor are (2s ₁ −1) × 360 / (4N) deg. (Where s ₁ is a natural number including 0),
The radial hall sensor and the circumferential hall sensor are arranged so that the amplitude of the magnetic flux density component received by the radial hall sensor and the amplitude of the magnetic flux density component received by the circumferential hall sensor are the same. Has been
A rotation angle detecting device that detects a rotation angle by combining outputs of the radial hall sensor and the circumferential hall sensor.   3. The arrangement according to claim 1, wherein a distance r between the magnetic pole outer peripheral surface of the magnet rotor and the magnetic sensing center of the hall sensor is such that r of the radial hall sensor is larger than r of the circumferential hall sensor. A rotation angle detection device characterized by being provided. In claim 1 or 2, for the distance h between the magnetic sensing center of the Hall sensor and a plane that passes through the thickness center point of the magnet rotor and is perpendicular to the rotation axis,
The rotation angle detecting device, wherein the radial hall sensor is arranged so that h of the radial hall sensor is larger than h of the circumferential hall sensor.   3. The inclination χ (where χ is in the range of 0 to 90 deg.) Of the magnetic sensor surface of the Hall sensor with respect to the rotation axis of the magnet rotor according to claim 1 or 2, A rotation angle detecting device arranged so that ≠ 0. A magnet rotor having N pole pairs of magnetic poles (where N is an integer of 2 or more) and four for detecting the rotation angle of the magnet rotor in accordance with the magnetic flux applied from the magnet rotor With a hall sensor
The four Hall sensors have first and second radial Hall sensors arranged with the magnetic sensitive axes directed in the radial direction of the magnet rotor, and the magnetic sensitive axes directed in the circumferential direction of the magnet rotor. A rotation angle detection device comprising: a first circumferential hall sensor and a second circumferential hall sensor arranged in the same manner. A magnet rotor having N pole pairs of magnetic poles (where N is an integer of 2 or more) and four for detecting the rotation angle of the magnet rotor in accordance with the magnetic flux applied from the magnet rotor With a hall sensor
The four Hall sensors have first and second radial Hall sensors arranged with the magnetic sensitive axes directed in the radial direction of the magnet rotor, and the magnetic sensitive axes directed in the circumferential direction of the magnet rotor. And the first and second circumferential hall sensors arranged
The first radial hall sensor and the second circumferential hall sensor are (2s ₁ −1) × 360 / (4N) deg. In the circumferential direction of the magnet rotor. (Where s ₁ is a natural number including 0),
The second radial hall sensor and the first circumferential hall sensor are (2s ₂ −1) × 360 / (4N) deg. In the circumferential direction of the magnet rotor. (Where s ₂ is a natural number including 0),
Synthesizing outputs of the first radial hall sensor and the second circumferential hall sensor, and synthesizing outputs of the second radial hall sensor and the first circumferential hall sensor; A rotation angle detecting device characterized by detecting a rotation angle. 8. The first and second radial hall sensors according to claim 7, wherein (2s ₃ −1) × 360 / (4N) deg. The rotation angle detecting device is provided so as to make an angle (where s ₃ is a natural number including 0). 9. The magnetic flux density component received by the first radial hall sensor and the amplitude of the magnetic flux density component received by the second circumferential hall sensor according to any one of claims 6 to 8. , Arranging the first radial hall sensor and the second circumferential hall sensor,
The second radial hall sensor so that the amplitude of the magnetic flux density component received by the second radial hall sensor is the same as the amplitude of the magnetic flux density component received by the first circumferential hall sensor. And a rotation angle detection device comprising the first circumferential hall sensor. In any one of Claims 6 thru | or 8, About the distance r of the magnetic pole outer peripheral surface of a magnet rotor, and the magnetic sensing center of a Hall sensor,
The first radial hall sensor is arranged so that r thereof is larger than r of the second circumferential hall sensor,
The rotation angle detecting device, wherein the second radial hall sensor is arranged such that r of the second radial hall sensor is larger than r of the first circumferential hall sensor. The distance h between the magnetosensitive center of the Hall sensor and a plane passing through the thickness center point of the magnet rotor and perpendicular to the rotation axis according to any one of claims 6 to 8.
The first radial hall sensor h is arranged to be larger than the second circumferential hall sensor h,
The rotation angle detecting device, wherein the second radial hall sensor is arranged such that h of the second radial hall sensor is larger than h of the first circumferential hall sensor. 9. The inclination χ (where χ is in the range of 0 to 90 deg.) Of the magnetosensitive surface of the Hall sensor with respect to the rotation axis of the magnet rotor according to claim 6.
The first radial Hall sensor χ is arranged so that ≠ 0,
The rotation angle detecting device, wherein the second radial hall sensor is arranged such that χ is not equal to zero. The distance r between the magnetic pole outer peripheral surface of the magnet rotor and the magnetic sensitive center of the Hall sensor according to any one of claims 6 to 12.
R of the first radial hall sensor is equal to r of the second radial hall sensor;
The rotation angle detector according to claim 1, wherein r of the first circumferential hall sensor is equal to r of the second circumferential hall sensor. The distance h between the magnetosensitive center of the Hall sensor and a plane passing through the thickness center point of the magnet rotor and perpendicular to the rotation axis according to any one of claims 6 to 12.
H of the first radial hall sensor is equal to h of the second radial hall sensor;
The rotation angle detecting device according to claim 1, wherein h of the first circumferential hall sensor is equal to h of the second circumferential hall sensor. 13. The inclination χ (where χ is in the range of 0 to 90 deg.) Of the magnetically sensitive surface of the Hall sensor with respect to the rotation axis of the magnet rotor according to claim 6.
Χ of the first radial hall sensor is equal to χ of the second radial hall sensor,
The rotation angle detector according to claim 1, wherein χ of the first circumferential hall sensor is equal to χ of the second circumferential hall sensor.   A rotating machine comprising the rotation angle detecting device according to any one of claims 1 to 15.

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