JP5151958B2 - POSITION DETECTION DEVICE AND ROTARY LINEAR MOTOR HAVING THE SAME - Google Patents
POSITION DETECTION DEVICE AND ROTARY LINEAR MOTOR HAVING THE SAME Download PDFInfo
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Description
本発明は、回転運動と直動運動を行う軸の回転位置と直動位置を同時に検出する位置検出装置およびそれを備えた回転直動モータに関する。
The present invention relates to a position detection device that simultaneously detects a rotational position and a linear motion position of a shaft that performs a rotational motion and a linear motion, and a rotary linear motion motor including the position detection device.
従来のモータ軸の回転運動と軸方向への運動(以下、直動運動)を同時に行う回転直動モータの位置検出装置は、回転運動と直動運動の位置検出を別々の装置で行うようにしていた。（例えば、特許文献１、２参照）。 A conventional rotary linear motor position detection device that simultaneously performs rotational motion of the motor shaft and axial motion (hereinafter referred to as linear motion) is configured to detect the position of rotational motion and linear motion separately. It was. (For example, refer to Patent Documents 1 and 2).
図１４は特許文献１に記載された回転直動モータの回転に関する位置検出部の側断面図である。
図において、モータ部１では、モータ軸９が回転運動を行うような構成をしており、回転用の位置検出部２は、直動軸受３が回転軸受４に回転自在に取り付け支持されている。従って、直動軸受３はモータ軸９と同期回転し、モータ軸９の軸方向の移動が可能となっている。回転信号発生部５は直動軸受３に同期回転してモータ軸の回転信号を発する。回転信号検出部６は、回転信号発生部５からの信号を定位置で受けてモータ軸９の回転位置を検出する。
FIG. 14 is a side cross-sectional view of a position detection unit relating to rotation of the rotary linear motor described in Patent Document 1.
In the figure, the motor unit 1 is configured such that the motor shaft 9 performs a rotational motion, and the position detecting unit 2 for rotation is supported by the linear motion bearing 3 being rotatably attached to the rotary bearing 4. . Therefore, the linear motion bearing 3 rotates synchronously with the motor shaft 9 so that the motor shaft 9 can move in the axial direction. The rotation signal generator 5 rotates in synchronization with the linear motion bearing 3 and generates a rotation signal of the motor shaft. The rotation signal detector 6 receives the signal from the rotation signal generator 5 at a fixed position and detects the rotation position of the motor shaft 9.
また図１５は回転直動モータの直動に関する位置検出部の側断面図を示したものである。図において、モータ部１では、モータ軸９が直動運動を行うような構成をしており、直動用の位置検出部２では、直動軸受３が回転軸受４を介してモータ軸９の下端部を支持している。直動信号発生部７はモータ軸９の直動運動に対してのみ直動軸受３と同期して移動することにより、モータ軸９の直動信号を発する。直動信号検出部８は、直動信号発生部７からの信号を受けて、モータ軸９の直動位置を検出する。 FIG. 15 is a side sectional view of the position detection unit related to the linear motion of the rotary linear motion motor. In the figure, the motor unit 1 is configured such that the motor shaft 9 performs a linear motion. In the linear motion position detection unit 2, the linear motion bearing 3 is connected to the lower end of the motor shaft 9 via the rotary bearing 4. Supporting the department. The linear motion signal generator 7 generates a linear motion signal of the motor shaft 9 by moving in synchronization with the linear motion bearing 3 only with respect to the linear motion of the motor shaft 9. The linear motion signal detection unit 8 receives the signal from the linear motion signal generation unit 7 and detects the linear motion position of the motor shaft 9.
従来の回転直動モータでは、回転位置と直動位置を同時に検出する場合、モータ軸９を長く延ばし、図１４と図１５に示した回転用と直動用の位置検出部２を直動方向に並べて構成する必要があった。
このように、従来の回転直動モータは、モータ軸の回転・直動位置を検出する装置を別々に組み合わせて構成していたため、位置検出装置が大きくなるという問題があった。
さらに、モータ軸の回転・直動運動がそれぞれ、回転・直動位置の検出に干渉しないよう、位置検出部に回転軸受と直動軸受を組み合わせて使用するため、回転軸受と直動軸受の組み立て精度や軸受のあそびの影響により検出誤差が発生するという問題があった。
本発明はこのような問題点に鑑みてなされたものであり、小型かつ精度の良い位置検出装置およびそれを備えた回転直動モータを提供することを目的とする。
As described above, since the conventional rotary / linear motion motor is configured by separately combining devices for detecting the rotation / linear motion position of the motor shaft, there is a problem that the position detection device becomes large.
In addition, since the rotation and linear motion of the motor shaft does not interfere with the detection of the rotation and linear motion position, respectively, the position detector is used in combination with a rotary bearing and linear motion bearing. There was a problem that a detection error occurred due to the influence of accuracy and play of the bearing.
The present invention has been made in view of such problems, and an object of the present invention is to provide a small and accurate position detection device and a rotary linear motion motor including the same.
上記問題を解決するため、本発明は、次のように構成したのである。
一観点による本発明は、回転運動と直動運動が可能となるよう支持された軸と、
前記軸に固定された永久磁石と、
前記永久磁石に空隙を介して対向し、固定体に取り付けられた磁界検出素子と、
前記磁界検出素子からの信号を処理する信号処理回路とを備えた位置検出装置において、前記磁界検出素子は前記永久磁石の回転方向側面に２個配置され、
２個の磁界検出素子からの検出信号は９０度の位相差をもち、
前記磁界検出素子が検出する磁束密度は前記軸の回転方向に対して正弦波状に変化し、
直動方向に対して磁束密度の振幅が位置に関して変化するように構成した磁気回路を備え、
前記磁界検出素子からの２検出信号から回転位置と直動位置を求める。
また、上記発明は、前記２個の磁界検出素子の２つの検出信号の比の逆正接演算から回転位置を、また前記２つの検出信号の二乗和の平方根演算により直動位置を検出してもよい。
In order to solve the above problem, the present invention is configured as follows.
According to one aspect of the present invention, there is provided a shaft supported so as to be capable of rotational motion and linear motion;
A permanent magnet fixed to the shaft;
A magnetic field detection element that is opposed to the permanent magnet via a gap and is attached to a fixed body,
And a signal processing circuit that processes a signal from the magnetic field detection element, wherein the two magnetic field detection elements are arranged on a side surface in the rotation direction of the permanent magnet,
The detection signals from the two magnetic field detection elements have a phase difference of 90 degrees,
The magnetic flux density detected by the magnetic field detection element changes sinusoidally with respect to the rotational direction of the shaft,
A magnetic circuit configured such that the amplitude of the magnetic flux density changes with respect to the position with respect to the linear motion direction;
The rotational position and the linear motion position are obtained from the two detection signals from the magnetic field detection element.
Further, the invention provides a rotational position from the arctangent calculation of the ratio of the two detection signals of the two magnetic field detecting elements, and also to detect the linear motion position by square root of the square sum of the two detection signals Good.
また、上記発明は、前記永久磁石は前記軸の直動方向に円錐台形状となっており、前記軸に対して垂直方向に２極着磁されてもよい。
また、上記発明は、前記永久磁石を焼結磁石またはボンド磁石で円錐台形状に成形の後、前記軸に対して垂直方向に２極着磁されてもよい。
また、上記発明は、前記永久磁石は複数個の永久磁石が前記軸の直動方向に並べて配置され、各々の前記永久磁石は前記軸に対して垂直方向に２極着磁され、各々の前記永久磁石の極は同じ方向になるように並べられ、各々の前記永久磁石の半径は前記軸の直動方向とともに変えられており、前記軸の直動方向に並べたときに前記複数の永久磁石が形成する稜線が円錐台形状になるようにしてもよい。
In the invention described above , the permanent magnet may have a truncated cone shape in the linear motion direction of the shaft, and may be magnetized in two poles in a direction perpendicular to the shaft .
In the above invention, the permanent magnet may be magnetized in a direction perpendicular to the axis after being formed into a truncated cone shape with a sintered magnet or a bonded magnet .
In the invention, the permanent magnet includes a plurality of permanent magnets arranged side by side in the linear movement direction of the shaft, and each of the permanent magnets is magnetized in two poles in a direction perpendicular to the shaft. The poles of the permanent magnets are arranged in the same direction, and the radius of each of the permanent magnets is changed together with the linear movement direction of the shaft, and the plurality of permanent magnets when arranged in the linear movement direction of the shaft The ridgeline formed by may have a truncated cone shape .
また、上記発明は、前記円錐台形状の永久磁石の稜線を凹曲面としてもよい。
また、上記発明は、前記円錐台形状の永久磁石の稜線を凸曲面としてもよい。
また、上記発明は、前記円錐台形状の永久磁石の稜線を凹曲面と凸曲面を組み合わせた形状としてもよい。
また、上記発明は、前記軸がモータの回転軸であってもよい。
また、他の観点による本発明は、前記位置検出装置を搭載した回転直動モータであってもよい。
Moreover, the said invention is good also considering the ridgeline of the said truncated cone-shaped permanent magnet as a concave curved surface .
Moreover, the said invention is good also considering the ridgeline of the said truncated cone-shaped permanent magnet as a convex curve .
Moreover, the said invention is good also as a shape which combined the concave curved surface and the convex curved surface with the ridgeline of the said truncated cone-shaped permanent magnet .
In the invention described above , the shaft may be a rotating shaft of a motor .
Further, the present invention according to another aspect may be a rotary linear motor equipped with the position detecting device .
また、更に他の観点による本発明は、回転運動と直動運動が可能となるよう支持された軸と、前記軸に固定された円筒状の永久磁石と、前記永久磁石に空隙を介して対向し、固定体に取り付けられた磁界検出素子と、前記磁界検出素子からの信号を処理する信号処理回路とを備えた位置検出装置において、前記磁界検出素子は前記永久磁石の回転方向側面に２個配置され、２個の磁界検出素子からの検出信号は９０度の位相差をもち、前記円筒状の永久磁石は磁界検出素子が検出する磁束密度が前記軸の回転方向に対して正弦波状に変化し、
直動方向に対しては磁束密度の振幅が位置に関して線形特性又は一価関数の非線形特性で変化するように着磁されており、前記磁界検出素子からの２検出信号から回転位置と直動位置を求める。
また、上記発明は、前記永久磁石は焼結磁石またはボンド磁石で円筒形状に成形の後、前記軸に対して垂直方向に２極着磁してもよい。
また、更に他の観点による本発明は、前記２個の磁界検出素子の２つの検出信号の比の逆正接演算から回転位置を検出し、直動位置検出に関し、前記磁束密度特性が線形特性の場合は前記２つの検出信号を二乗和の平方根演算して得られる値から直動位置を検出し、前記磁束密度が前記非線形特性の場合は更に前記一価関数の逆関数を計算することにより直動位置を検出する。
According to still another aspect of the present invention , there is provided a shaft supported so as to be capable of rotational motion and linear motion, a cylindrical permanent magnet fixed to the shaft, and opposed to the permanent magnet through a gap. In the position detection device including a magnetic field detection element attached to a fixed body and a signal processing circuit for processing a signal from the magnetic field detection element, two magnetic field detection elements are provided on the side surface in the rotation direction of the permanent magnet. The detection signals from the two magnetic field detection elements have a phase difference of 90 degrees, and the cylindrical permanent magnet changes the magnetic flux density detected by the magnetic field detection element in a sinusoidal shape with respect to the rotation direction of the shaft. And
With respect to the linear motion direction, the amplitude of the magnetic flux density is magnetized so as to change with a linear characteristic or a non-linear characteristic of a monovalent function with respect to the position, and the rotational position and the linear motion position are detected from the two detection signals from the magnetic field detection element. Ask for .
In the above invention, the permanent magnet may be magnetized in a perpendicular direction with respect to the axis after being formed into a cylindrical shape by a sintered magnet or a bonded magnet .
According to still another aspect of the present invention , the rotational position is detected from the arc tangent calculation of the ratio of the two detection signals of the two magnetic field detection elements, and the magnetic flux density characteristic is linear. In this case, the linear motion position is detected from a value obtained by calculating the square root of the sum of squares of the two detection signals. If the magnetic flux density is the nonlinear characteristic, the inverse function of the monovalent function is further calculated. Detect the moving position .
以上、本発明によると、磁界検出素子が検出する磁束密度が円周方向には正弦波状に変化し、軸の軸方向に向かって直線状に変化するようにし、磁界検出素子は９０度間隔で２個設けられており、軸の回転位置を２つの検出信号の比の逆正接演算から、また軸の直動位置を２つの検出信号の二乗和の平方根演算により求めることができるので、磁気式エンコーダを小型化することができる。
また、構成が単純なため組み立て精度や軸受のあそびの影響による検出誤差を小さくすることができる。
As described above, according to the present invention, the magnetic flux density detected by the magnetic field detecting element changes in a sine wave shape in the circumferential direction and changes linearly in the axial direction of the shaft. Two are provided, and the rotational position of the shaft can be obtained from the arctangent calculation of the ratio of the two detection signals, and the linear movement position of the shaft can be obtained by the square root calculation of the sum of squares of the two detection signals. The encoder can be reduced in size.
In addition, since the configuration is simple, detection errors due to the effects of assembly accuracy and play of the bearing can be reduced.
また、本発明によると、前記永久磁石は軸の軸方向に円錐台形状となっており、２極着磁されている場合、磁束密度が回転方向には正弦波状に変化し、軸の直動方向に直線状に変化するように分布させることが可能になる。
また、本発明によると、前記永久磁石を焼結磁石またはボンド磁石を用いる場合、容易に成形することができる。
Further, according to the present invention, the permanent magnet has a frustoconical axial direction of the shaft, if it is two-pole magnetized, changes sinusoidally in the magnetic flux density direction of rotation of the shaft linear The distribution can be performed so as to change linearly in the direction.
Further, according to the present invention, the permanent magnet when using the sintered magnet or a bonded magnet, can be easily molded.
また、本発明によると、前記永久磁石は複数の永久磁石を軸の直動方向に並べて構成され、それぞれの永久磁石は２極着磁されており、それぞれの永久磁石の極は同じ方向になるように並べられ、それぞれの永久磁石の半径は軸の直動方向とともに変えられており、軸の直動方向に並べたときに円錐台形状になるようにした場合、磁束密度が円周方向には正弦波状に変化し、軸の直動方向に向かって直線状に変化するように分布させることができる。 Further , according to the present invention, the permanent magnet is configured by arranging a plurality of permanent magnets in the linear movement direction of the shaft, each permanent magnet is magnetized in two poles, and the poles of each permanent magnet are in the same direction. The radius of each permanent magnet is changed with the linear motion direction of the shaft, and when it is arranged in the shape of a truncated cone when aligned in the linear motion direction of the shaft , the magnetic flux density is increased in the circumferential direction. Can be distributed so as to change sinusoidally and change linearly in the linear motion direction of the shaft.
また、本発明によると、円錐台の稜線を曲線形状とする場合、軸方向位置に対する磁束密度変化の直線性を向上させることが可能になる。
また、本発明によると、軸をモータの回転軸を用い直接に磁石を取り付ける場合、小型に構成できる。
また、本発明によると、小型の位置検出装置を取付ける場合、回転直動モータ自体を小型に構成できる。
また、本発明によると、永久磁石を円筒形状にする場合、容易に製造することができる。また、軸の直動方向の移動ストロークを長くすることができる。
また、本発明によると、軸方向の特性が非線形特性であっても一価関数で表される特性である場合、補正することで高精度の直動位置を測定できる。
Further , according to the present invention, when the ridge line of the truncated cone is curved, it is possible to improve the linearity of the magnetic flux density change with respect to the axial position.
Further, according to the present invention, when mounting the magnets directly using the rotation shaft of the motor axis, it can be configured compact.
Further , according to the present invention, when a small position detecting device is mounted , the rotary linear motor itself can be configured in a small size.
Further, according to the present invention, when the permanent magnets in a cylindrical shape, can be easily manufactured. Further, the movement stroke of the shaft in the linear motion direction can be lengthened.
Further , according to the present invention, even if the axial characteristic is a nonlinear characteristic, if it is a characteristic represented by a monovalent function, a highly accurate linear motion position can be measured by correcting it.
以下、本発明の実施の形態について図を参照して説明する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
図１は本発明の回転直動モータの位置検出装置の構造を示す断面図である。
図１において１１はモータ部であり、１２は位置検出部である。１５は円錐台形状の永久磁石であり、モータ軸に対して垂直方向に２極に着磁されている。１３は固定体であり、磁気回路を形成するために、鉄や電磁鋼板などの磁性体で構成される。１４は磁界検出素子であり、第１の磁界検出素子１４１と第２の磁界検出素子１４２で構成され、第１の磁界検出素子１４１と第２の磁界検出素子１４２は永久磁石１５の回転方向側面に、それぞれ検出信号が９０度位相のずれた信号になるように配置されている。１６はモータ軸であり、回転運動と直動運動が可能となるよう支持されている。ただし、ここでは支持機構を省略している。円錐台形状の永久磁石１５は例えば圧粉磁心材料を用いた焼結磁石、もしくはフェライト磁石などの磁石を砕いてゴムやプラスチックに練り込んだ柔軟性のあるボンド磁石を用いて形成することができる。
FIG. 1 is a sectional view showing the structure of a position detecting device for a rotary direct acting motor according to the present invention.
In FIG. 1, 11 is a motor unit, and 12 is a position detection unit. Reference numeral 15 denotes a frustoconical permanent magnet, which is magnetized in two poles in a direction perpendicular to the motor shaft. Reference numeral 13 denotes a fixed body, which is composed of a magnetic body such as iron or an electromagnetic steel plate in order to form a magnetic circuit. Reference numeral 14 denotes a magnetic field detection element, which includes a first magnetic field detection element 141 and a second magnetic field detection element 142, and the first magnetic field detection element 141 and the second magnetic field detection element 142 are side surfaces in the rotational direction of the permanent magnet 15. In addition, the detection signals are arranged so that the signals are 90 degrees out of phase. Reference numeral 16 denotes a motor shaft, which is supported so as to be capable of rotating and linear motion. However, the support mechanism is omitted here. The frustum-shaped permanent magnet 15 can be formed by using, for example, a sintered magnet using a powder magnetic core material or a flexible bonded magnet obtained by crushing a magnet such as a ferrite magnet and kneading it into rubber or plastic. .
図２は図１のＡ−Ａ’における磁石の断面と磁化方向を示したものである。
磁石１５を２極としているので、第１の磁界検出素子１４１と第２の磁界検出素子１４２の検出信号をモータ軸の回転に対して９０度位相のずれた信号とするために、２つの磁界検出素子をそれぞれ機械角で９０度離れた位置に配置する。
本実施例が従来の実施例と異なる点は、これまで別々の検出装置を用いて検出していた回転方向と直動方向の位置検出を、２個の磁界検出素子を用いて回転方向と直動方向の位置を同時に検出する点である。
本実施例の動作について説明する。図３は軸の回転位置と直動位置に対する磁界検出素子の検出磁束密度の変化を示したものである。軸の回転運動に対して磁界検出素子の検出磁束密度は正弦波状に変化し、軸の直動運動に対しては、検出磁束密度は直線的に変化する。図４は回転方向の位置をある位置に固定して、直動方向の位置を変化させた時の磁束密度の振幅の変化を模式的に示したものである。
直動方向の位置ｚの検出範囲をＺ１，Ｚ２とし、Ｚ１，Ｚ２の位置における磁束密度をＢ１，Ｂ２とすれば、この磁束密度分布は次式で表すことができる。
回転角θｐ、直動方向の位置をＺｐとすれば、この位置における第１の磁界検出素子１４１および第２の磁界検出素子１４２が出力する電圧Ｖ１，Ｖ２は次のようになる。
ここでＫは磁界検出素子が出力する電圧と磁束密度との比例定数である。
従って回転角θpは２つの磁界検出素子の検出信号の比の逆正接演算により、すなわち次式で求めることができる。
また、直動位置Ｚpは２つの磁界検出素子の検出信号の二乗和の平方根演算、すなわち次式で求めることができる。
ここでＣ1,Ｃ2は定数であり、次のように表される。
このように本実施例では、回転位置と直動位置の検出が２個の磁界検出素子の出力を用いることで可能になるので、小型の位置検出装置が実現することができる。
FIG. 2 shows a cross section and a magnetization direction of the magnet at AA ′ in FIG.
Since the magnet 15 has two poles, two magnetic fields are used in order to make the detection signals of the first magnetic field detection element 141 and the second magnetic field detection element 142 out of phase by 90 degrees with respect to the rotation of the motor shaft. The detection elements are respectively arranged at positions separated by 90 degrees in mechanical angle.
The difference between the present embodiment and the conventional embodiment is that the position detection in the rotational direction and the linear motion direction, which have been detected by using different detection devices so far, is performed by using two magnetic field detection elements. This is the point where the position in the moving direction is detected simultaneously.
The operation of this embodiment will be described. FIG. 3 shows changes in the detected magnetic flux density of the magnetic field detecting element with respect to the rotational position and the linear motion position of the shaft. The detected magnetic flux density of the magnetic field detecting element changes sinusoidally with respect to the rotational movement of the shaft, and the detected magnetic flux density changes linearly with respect to the linear motion of the shaft. FIG. 4 schematically shows changes in the magnetic flux density amplitude when the position in the rotational direction is fixed at a certain position and the position in the linear motion direction is changed.
If the detection range of the position z in the linear motion direction is Z1 and Z2, and the magnetic flux density at the position of Z1 and Z2 is B1 and B2, this magnetic flux density distribution can be expressed by the following equation.
If the rotation angle θp and the position in the linear motion direction are Zp, the voltages V1 and V2 output from the first magnetic field detection element 141 and the second magnetic field detection element 142 at this position are as follows.
Here, K is a proportional constant between the voltage output from the magnetic field detection element and the magnetic flux density.
Therefore, the rotation angle θp can be obtained by the arc tangent calculation of the ratio of the detection signals of the two magnetic field detection elements, that is, the following equation.
The linear motion position Zp can be obtained by the square root calculation of the sum of squares of the detection signals of the two magnetic field detection elements, that is, the following equation.
Here, C1 and C2 are constants and are expressed as follows.
As described above, in this embodiment, the rotation position and the linear movement position can be detected by using the outputs of the two magnetic field detection elements, so that a small position detection apparatus can be realized.
図５は第２の実施例を示す回転直動モータの位置検出装置の断面図である。図において１７は半径が異なる円筒状の永久磁石を複数重ね、稜線を円錐台形状としたものである。各々の永久磁石は２極に着磁されており、磁極が同じ方向になるように重ねられている。図６は図５のＢ−Ｂ’における磁石の断面と磁化方向を示したものである。
このように本実施例では、焼結磁石やボンド磁石のような一体の成形磁石を使用しなくても実施例１と同機能の位置検出装置を実現することができる。
FIG. 5 is a cross-sectional view of a position detecting device for a rotary linear motor showing a second embodiment. In the figure, reference numeral 17 denotes a plurality of cylindrical permanent magnets having different radii, and a ridge line having a truncated cone shape. Each permanent magnet is magnetized in two poles, and the magnetic poles are stacked so that they are in the same direction. FIG. 6 shows the cross section and the magnetization direction of the magnet at BB ′ in FIG.
As described above, in the present embodiment, a position detecting device having the same function as that of the first embodiment can be realized without using an integrated molded magnet such as a sintered magnet or a bonded magnet.
図７は第３の実施例を示す磁石の形状である。図７（a）は永久磁石を一体で形成した場合を示し、図７（b）は円筒状の永久磁石を複数個積み重ねた場合を示す。磁石端部において漏れ磁束の影響が大きくなる場合、磁石端部付近に磁界検出素子が対抗すると、検出磁束密度が著しく減少するため、図に示すように端部付近の磁石の径を大きくし、円錐台形状の稜線を凹曲面にすることで、軸方向位置の変化に対する磁束密度の直線性を向上させることができる。
FIG. 7 shows the shape of a magnet according to the third embodiment. FIG. 7A shows a case where the permanent magnets are integrally formed, and FIG. 7B shows a case where a plurality of cylindrical permanent magnets are stacked. When the influence of leakage magnetic flux becomes large at the magnet end, if the magnetic field detection element counteracts near the magnet end, the detected magnetic flux density is remarkably reduced, so the diameter of the magnet near the end is increased as shown in the figure, By making the frustoconical ridge line into a concave curved surface, the linearity of the magnetic flux density with respect to the change in the axial position can be improved.
図８は第４の実施例を示す磁石の形状である。図８（a）は永久磁石を一体で形成した場合を示し、図８（b）は円筒状の永久磁石を複数個積み重ねた場合を示す。磁石端部の漏れ磁束の影響が無視できる場合、中央部の磁石の径を大きくし、端部の磁石の径を小さく円錐台形状の稜線を凸曲面にし、軸方向位置の変化に対する磁束密度の直線性を向上させることができる。このような形状にする理由を以下に述べる。
磁界検出素子の検出磁束密度の大きさは、磁石の発生する磁束密度の大きさと、磁石周面から磁界検出素子までの距離に依存する。磁石の発生する磁束密度は磁石形状と周辺に存在する磁性体により定まるパーミアンス係数で決まる。磁石径が大きい場合、内部に発生する反磁界が減少するとともに、磁石と磁性体でできた固定体までの距離が短くなるため、パーミアンス係数が大きくなり、磁石の発生する磁束密度は大きくなる。さらに、磁石径が大きい場合、磁石面から磁界検出素子までの距離が短くなるため、磁界検出素子の検出磁束密度は大きくなる。以上の２つの効果により、検出磁束密度は磁石の径に対して、単純に比例するのではなく、１．５〜２乗程度に比例する。したがって、円錐台磁石の中央部を凸曲面にすることで、軸方向位置の変化に対する磁束密度の直線性を向上させることができる。
FIG. 8 shows the shape of a magnet according to the fourth embodiment. FIG. 8A shows a case where the permanent magnets are integrally formed, and FIG. 8B shows a case where a plurality of cylindrical permanent magnets are stacked. When the influence of leakage magnetic flux at the magnet end is negligible, the diameter of the magnet at the center is increased, the diameter of the magnet at the end is decreased, the frustoconical ridge is formed as a convex curved surface, and Linearity can be improved. The reason for this shape will be described below.
The magnitude of the detected magnetic flux density of the magnetic field detecting element depends on the magnitude of the magnetic flux density generated by the magnet and the distance from the magnet circumferential surface to the magnetic field detecting element. The magnetic flux density generated by the magnet is determined by the permeance coefficient determined by the magnet shape and the surrounding magnetic material. When the magnet diameter is large, the demagnetizing field generated inside decreases and the distance between the magnet and the fixed body made of the magnetic material decreases, so that the permeance coefficient increases and the magnetic flux density generated by the magnet increases. Furthermore, when the magnet diameter is large, the distance from the magnet surface to the magnetic field detection element is shortened, so that the detected magnetic flux density of the magnetic field detection element is increased. Due to the above two effects, the detected magnetic flux density is not simply proportional to the diameter of the magnet, but is proportional to about 1.5 to the square. Therefore, by making the central portion of the truncated cone magnet a convex curved surface, the linearity of the magnetic flux density with respect to the change in the axial position can be improved.
図９は第５の実施例を示す磁石の形状である。図９（a）は永久磁石を一体で形成した場合を示し、図９（b）は円筒状の永久磁石を複数個積み重ねた場合を示す。
磁石端部近傍については、実施例３に示したように、漏れ磁束による磁束密度の減少分を補正するために、磁石径を大きくし、円錐台形状の稜線を凹曲面にする。
一方、磁石中央部の径については、実施例４に示したように、磁石のパーミアンス係数と磁界検出素子までの距離を考慮して、円錐台形状の稜線を凸曲面にする。
このような磁石形状にすることで、直動方向の広い領域で、軸方向位置の変化に対する磁束密度の直線性を向上させることができる。
FIG. 9 shows the shape of a magnet according to the fifth embodiment. FIG. 9A shows a case where the permanent magnets are integrally formed, and FIG. 9B shows a case where a plurality of cylindrical permanent magnets are stacked.
In the vicinity of the magnet end portion, as shown in the third embodiment, in order to correct the decrease in the magnetic flux density due to the leakage magnetic flux, the magnet diameter is increased and the frustoconical ridge line is formed into a concave curved surface.
On the other hand, with respect to the diameter of the magnet central portion, as shown in the fourth embodiment, the frustoconical ridge line is formed as a convex curved surface in consideration of the permeance coefficient of the magnet and the distance to the magnetic field detection element.
By adopting such a magnet shape, the linearity of the magnetic flux density with respect to the change in the axial position can be improved in a wide region in the linear motion direction.
図１０は本発明の第６の実施例を示す回転直動モータの位置検出装置の構造を示す断面図である。 実施例１との違いは１５が円筒形状の永久磁石であり、モータ軸１６に対して垂直方向に２極に着磁され、軸方向に磁化が漸増するように着磁されていることである。他の構成要素は同じであるので説明は省略する。本実施例では２極で構成しているが、多極であっても同様に構成することができる。
図１１は図１０の永久磁石１５のみを取り出した側断面図であり、磁化の様子を示したものである。永久磁石１５は軸方向に磁化が漸増するように着磁される。すなわち、第１の磁界検出素子１４１および、第２の磁界検出素子１４２の検出信号がモータ軸の直動位置に対して、概ね線形的に増減するように、着磁が施される。
本実施例の動作は実施例１で説明した動作と同じになるためここでは説明を省略する。
FIG. 10 is a sectional view showing the structure of a position detecting device for a rotary linear motion motor according to a sixth embodiment of the present invention. The difference from the first embodiment is that 15 is a cylindrical permanent magnet, which is magnetized in two poles perpendicular to the motor shaft 16 and magnetized so that the magnetization gradually increases in the axial direction. . Since other components are the same, description thereof is omitted. In this embodiment, it is configured with two poles, but it can be configured similarly even with multiple poles.
FIG. 11 is a side sectional view showing only the permanent magnet 15 of FIG. 10 and shows the state of magnetization. The permanent magnet 15 is magnetized so that the magnetization gradually increases in the axial direction. That is, magnetization is performed so that the detection signals of the first magnetic field detection element 141 and the second magnetic field detection element 142 increase or decrease substantially linearly with respect to the linear movement position of the motor shaft.
Since the operation of this embodiment is the same as that described in the first embodiment, the description thereof is omitted here.
図１２に本実施例における永久磁石の着磁方法に関し、着磁器と永久磁石の断面図を示した例である。図において１５は円筒状の永久磁石であり、着磁コイル２１に通電を行い、着磁磁極２０から発生する磁束を受け、着磁が施される。
この場合、永久磁石１５は軸に対して垂直方向に２極着磁され、軸方向には永久磁石の磁化が漸増するように着磁される。すなわち、上部においては永久磁石１５の周面から着磁磁極面までの距離が長いため永久磁石１５の磁化は低いが、永久磁石１５の下部に行くほど磁化は大きくなる。このようにして、一度の通電により、永久磁石１５を着磁することができる。
FIG. 12 shows an example of a sectional view of a magnetizer and a permanent magnet with respect to the method for magnetizing the permanent magnet in the present embodiment. In the figure, reference numeral 15 denotes a cylindrical permanent magnet, which energizes the magnetizing coil 21 to receive a magnetic flux generated from the magnetized magnetic pole 20 and is magnetized.
In this case, the permanent magnet 15 is two-pole magnetized in a direction perpendicular to the axis, and is magnetized so that the magnetization of the permanent magnet gradually increases in the axis direction. That is, in the upper part, since the distance from the peripheral surface of the permanent magnet 15 to the magnetized magnetic pole surface is long, the magnetization of the permanent magnet 15 is low, but the magnetization increases toward the lower part of the permanent magnet 15. In this way, the permanent magnet 15 can be magnetized by a single energization.
永久磁石の周方向に磁束密度が正弦波状に変化させるような着磁を行うことはさほど難しくないが、円筒状永久磁石の軸方向に磁束密度が線形的に変化させるように着磁するのは比較的難しい。図１３に示すように軸方向の位置Ｚに対して、検出磁束密度Ｂは非線形に変化することがある。
このような場合、検出磁束密度Ｂ（θ，ｚ）は、直動位置ｚの一価関数ｆ（ｚ）を用いて、以下のように表すことができる。
ここで、モータ軸のある回転角θｐ、直動方向の位置Ｚｐおいて、第１の磁界検出素子１４１および第２の磁界検出素子１４２が出力する、それぞれの電圧Ｖ１，Ｖ２は次のようになる。
ここで、ｆ（Ｚｐ）は第１、第２の磁界検出素子が出力する電圧Ｖ１，Ｖ２から、
と表されるので、直動位置Ｚｐは
で定められる。ただし、一般的にはｆ−１（Ｚｐ）を理論的に求めることが困難であるので、あらかじめ、位置と出力電圧に対する複数個のサンプリングデータを取得し、ｆ−１（Ｚｐ）を例えば多項式補間などを行い表現することができる。
このようにして、直動位置Ｚｐを定めることができる。
Although it is not so difficult to magnetize the magnetic flux density to change in the circumferential direction of the permanent magnet, it is difficult to magnetize the magnetic flux density to change linearly in the axial direction of the cylindrical permanent magnet. Relatively difficult. As shown in FIG. 13, the detected magnetic flux density B may change non-linearly with respect to the position Z in the axial direction.
In such a case, the detected magnetic flux density B (θ, z) can be expressed as follows using the monovalent function f (z) of the linear motion position z.
Here, at the rotation angle θp of the motor shaft and the position Zp in the linear motion direction, the respective voltages V1 and V2 output from the first magnetic field detection element 141 and the second magnetic field detection element 142 are as follows: Become.
Here, f (Zp) is obtained from the voltages V1 and V2 output from the first and second magnetic field detecting elements.
Therefore, the linear motion position Zp is
Determined by However, since it is generally difficult to determine f -1 a (Zp) theoretically beforehand, it obtains a plurality of sampling data with respect to the position and the output voltage, f -1 a (Zp) for example polynomial interpolation Can be expressed.
In this way, the linear motion position Zp can be determined.
以上のように磁界検出素子が検出する磁束密度が軸の回転方向には正弦波状に変化し、かつ、軸の直動方向には磁束密度の振幅が直線状に変化するように構成した磁気回路と、その磁界変化を２つの磁界検出素子で検出し、９０度位相の異なる検出信号から回転と直動の位置を検出するようにしたので、回転と直動の位置を同時に検出する小型の磁気式エンコーダ装置を実現することができる。
なお、上記実施例の説明では軸としてモータ軸としたが軸はモータ軸に限らず、たとえば検出器としての専用の軸であっても良い。
As described above, a magnetic circuit configured such that the magnetic flux density detected by the magnetic field detecting element changes in a sinusoidal shape in the rotational direction of the shaft, and the amplitude of the magnetic flux density changes linearly in the linear motion direction of the shaft. The change in the magnetic field is detected by two magnetic field detection elements, and the rotation and linear motion positions are detected from detection signals that are 90 degrees out of phase. An encoder system can be realized.
In the description of the above embodiment, the motor shaft is used as the shaft. However, the shaft is not limited to the motor shaft, and may be a dedicated shaft as a detector, for example.
本発明によればモータ軸などの軸の回転位置と直動位置を小型の検出器で検出することができるので、回転直動モータなどの軸の位置検出装置としての用途へ適用することができる。
According to the present invention, since the rotational position and linear motion position of a shaft such as a motor shaft can be detected by a small detector, the present invention can be applied to a use as a position detection device for a shaft such as a rotational linear motion motor. .
１ モータ部
２ 位置検出部
３ 直動軸受
４ 回転軸受
５ 回転信号発生部
６ 回転信号検出部
７ 直動信号発生部
８ 直動信号検出部
９ モータ軸
１１ モータ部
１２ 位置検出部
１３ 固定体
１４ 磁界検出素子
１４１ 第１の磁界検出素子
１４２ 第２の磁界検出素子
１５ 永久磁石
１６ モータ軸
１７ 永久磁石
２０ 着磁磁極
２１ 着磁コイル
DESCRIPTION OF SYMBOLS 1 Motor part 2 Position detection part 3 Linear motion bearing 4 Rotary bearing 5 Rotation signal generation part 6 Rotation signal detection part 7 Linear motion signal generation part 8 Direct motion signal detection part 9 Motor shaft 11 Motor part 12 Position detection part 13 Fixed body 14 Magnetic field detection element 141 First magnetic field detection element 142 Second magnetic field detection element 15 Permanent magnet 16 Motor shaft 17 Permanent magnet 20 Magnetized magnetic pole 21 Magnetized coil
Claims (9)
前記軸に固定された永久磁石と、
前記永久磁石に空隙を介して対向し、固定体に取り付けられた磁界検出素子と、
前記磁界検出素子からの信号を処理する信号処理回路と、
を備え、
前記磁界検出素子は、前記永久磁石の回転方向側面において、検出信号が相互に９０度の位相差を有する位置に２個配置され、
前記永久磁石は、前記磁界検出素子が検出する磁束密度が前記軸の回転運動に応じて正弦波状に変化し、かつ、前記磁束密度の振幅が前記軸の直動運動に応じて線形特性で変化するように形成され、
前記信号処理回路は、前記磁界検出素子からの２検出信号から回転位置と直動位置を求め、
前記永久磁石は、前記軸と垂直な方向に２極着磁され、かつ、前記軸と平行な方向における位置に応じて該軸と垂直な方向の半径が異なる形状を有すること
を特徴とする位置検出装置。 A shaft supported to allow rotational and linear motion;
A permanent magnet fixed to the shaft;
A magnetic field detection element that is opposed to the permanent magnet via a gap and is attached to a fixed body,
A signal processing circuit for processing a signal from the magnetic field detection element;
With
Two of the magnetic field detection elements are arranged at positions where the detection signals have a phase difference of 90 degrees from each other on the side surface in the rotational direction of the permanent magnet.
The permanent magnet, the magnetic flux density the magnetic field detection element detects changes sinusoidally in accordance with the rotation movement of the shaft, and the amplitude of said flux density in the linear characteristics in accordance with the linear motion of the shaft Formed to change,
The signal processing circuit obtains a rotation position and a linear movement position from two detection signals from the magnetic field detection element ,
The permanent magnet is dipole magnetized in a direction perpendicular to the axis, and has a shape in which the radius in the direction perpendicular to the axis differs depending on the position in the direction parallel to the axis.
A position detection device characterized by the above .
前記複数の永久磁石は、並べられた状態における稜線が円錐台形状となるように、前記軸と垂直な方向の半径が異なることを特徴とする請求項３または４に記載の位置検出装置。 The permanent magnet has a plurality of permanent magnets arranged in the axial direction so that the poles of the permanent magnets face in the same direction,
5. The position detection device according to claim 3, wherein the plurality of permanent magnets have different radii in a direction perpendicular to the axis so that a ridge line in the arranged state has a truncated cone shape.
前記軸に固定された永久磁石と、 A permanent magnet fixed to the shaft;
前記永久磁石に空隙を介して対向し、固定体に取り付けられた磁界検出素子と、 A magnetic field detection element that is opposed to the permanent magnet via a gap and is attached to a fixed body,
前記磁界検出素子からの信号を処理する信号処理回路と、 A signal processing circuit for processing a signal from the magnetic field detection element;
を備え、With
前記磁界検出素子は、前記永久磁石の回転方向側面において、検出信号が相互に９０度の位相差を有する位置に２個配置され、 Two of the magnetic field detection elements are arranged at positions where the detection signals have a phase difference of 90 degrees from each other on the side surface in the rotational direction of the permanent magnet.
前記永久磁石は、前記磁界検出素子が検出する磁束密度が前記軸の回転運動に応じて正弦波状に変化し、かつ、前記磁束密度の振幅が前記軸の直動運動に応じて線形特性又は一価関数の非線形特性で変化するように形成され、 In the permanent magnet, the magnetic flux density detected by the magnetic field detecting element changes in a sine wave shape according to the rotational motion of the shaft, and the amplitude of the magnetic flux density is linear or one-dimensional depending on the linear motion of the shaft. Formed to change with the non-linear characteristics of the valence function,
前記信号処理回路は、前記磁界検出素子からの２検出信号から回転位置と直動位置を求め、 The signal processing circuit obtains a rotation position and a linear movement position from two detection signals from the magnetic field detection element,
前記永久磁石は、前記軸と垂直な方向に２極着磁され、かつ、前記軸と平行な方向における位置に関わらず同じ半径の円筒形状であること The permanent magnet is two-pole magnetized in a direction perpendicular to the axis and has a cylindrical shape with the same radius regardless of the position in the direction parallel to the axis.
を特徴とする位置検出装置。 A position detection device characterized by the above.
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| JP6217596B2 (en) * | 2014-11-04 | 2017-10-25 | 株式会社デンソー | Rotation angle and stroke amount detection device |
| JP6801170B2 (en) * | 2015-09-10 | 2020-12-16 | 日立金属株式会社 | Manufacturing method of rotation angle detection magnet, rotation angle detection device and rotation angle detection magnet |
| JP7294744B2 (en) * | 2019-06-06 | 2023-06-20 | 株式会社Soken | meshing clutch |
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| JPH0550307U (en) * | 1991-12-03 | 1993-07-02 | パイオニア精密株式会社 | Linear sensor |
| JP4029679B2 (en) * | 2002-05-28 | 2008-01-09 | 愛知製鋼株式会社 | Bond magnet for motor and motor |
| JP5261913B2 (en) * | 2005-10-21 | 2013-08-14 | 株式会社安川電機 | Linear motion actuator and system |
| JP4607049B2 (en) * | 2006-02-23 | 2011-01-05 | 株式会社デンソー | Rotation angle detector |
| JP5036669B2 (en) * | 2008-09-12 | 2012-09-26 | 三菱電機株式会社 | Position detection device for moving parts, 2-DOF actuator |
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