JPH01233316A - Revolution detector - Google Patents

Abstract

PURPOSE:To make the speed of response high, to exclude the effect of an ambient temperature and to make a resolution high, by a construction wherein a rotary magnetic pole plate having magnetic poles of different polarities disposed alternately along the peripheral edge thereof is fixed concentrically to a rotary shaft and elements prepared by winding detecting coils on ferromagnetic slender wires respectively are disposed in close proximity to said plate. CONSTITUTION:A rotary shaft 2 is supported rotatably by a case 1, while a rotary magnetic pole plate 3 formed of a ferromagnetic material is fixed concentrically to the shaft. On the peripheral edge part of the rotary magnetic pole plate 3, S and N poles are magnetized alternately and adjacently at prescribed intervals, and a spatial magnetic field wherein polarities of S and N vary alternately and sinusoidally substantially is formed along said peripheral edge part. Detecting elements 4 and 5 are formed by winding detecting coils on the central parts of amorphous alloy slender wires 6 and 6 bent in the shape of U respectively, and the opposite end parts thereof are made parallel substantially to the axial direction of the rotary shaft 2 through the intermediary of supporting members 10 and 11. The detecting elements 4 and 5 are set so that the phases are shifted by 90 deg. from each other in terms of a magnetic flux distribution.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a 1M1 mechanical system that detects the rotational speed and/or angle of rotation used for positioning control in production automation equipment (hereinafter abbreviated as FA equipment). Regarding a detection device.

[Conventional technology]

FA equipment is rapidly becoming popular with the automation and labor saving in production equipment, and the most important components of FA equipment are high-speed and high-precision positioning control. For positioning control in FA equipment,
A rotation detection device, usually called a rotary encoder, is mainly used to optically or magnetically detect the rotation speed and rotation angle of a rotating plate. The optical type has many slits in the rotating plate, and the light passing through the slits is
It is detected using a light-receiving element such as an i (amorphous silicon) semiconductor, and the magnetic type magnetizes the outer periphery of the rotating plate so that S and N poles are arranged adjacent to each other alternately, and the polarity along the periphery is Changes are detected using a magnetic sensor. Although the optical type can improve resolution by forming the slit and the light-receiving element with high precision using precision processing technology, there is a problem with the response frequency due to the followability of the light-receiving element. on the other hand,
The magnetic type is not as good as the optical type in terms of resolution, but its response speed is superior to the optical type. The detection performance of the magnetic rotary encoder is determined by the magnetization technique of the rotating plate, as well as the characteristics and arrangement of the magnetic sensor that detects the magnetic flux due to the magnetized magnetic poles.

This magnetic sensor uses a Hall element or a magnetoresistive element made of a semiconductor or a ferromagnetic thin film, but the Hall element and semiconductor magnetoresistive element have the disadvantage that their output is easily affected by the ambient temperature. Further, in the case of ferromagnetic thin film resistive elements, there are drawbacks such as the need for highly accurate microfabrication techniques, detection methods for obtaining high resolution, and complex circuit designs for signal processing.

[Problem to be solved by the invention]

In view of the above-mentioned problems and drawbacks of conventional rotation detection devices, the present invention has excellent high-speed response, is not affected by ambient temperature (and has a high resolution based only on the number of magnetized magnetic poles). The problem to be solved is the construction of a simple magnetic rotation detection device that exhibits higher resolution than the above.

[Means to solve the problem]

In order to solve the above problems, according to the present invention, the configuration of a magnetic rotation detection device is such that a rotating shaft driven by a rotating body to be positioned has magnetic poles of different polarities alternately along the periphery. Rotating magnetic pole plates arranged at equal intervals are fixed concentrically, and a detection coil is wound around the center of a ferromagnetic thin wire made of an amorphous alloy. rotating magnetic pole plate rotation direction pins arranged near the peripheral edge of the magnetic pole plate at intervals of an odd multiple of 180° in a magnetic flux distribution that changes sinusoidally along the peripheral edge of the magnetic pole plate, and in both ends of the thin wires of the plurality of detection elements; The configuration is such that the side comrades or the subordinate side comrades are sequentially shifted at equal intervals in terms of phase within the width of 180° of the magnetic flux distribution.

[Effect]

By configuring the rotation detection device in this way, each time the magnetic pole of the rotating magnetic pole plate passes through both ends of a thin ferromagnetic wire made of an amorphous alloy disposed close to the periphery of the rotating magnetic pole plate, the magnetic pole of the rotating magnetic pole plate passes through the thin wire. The polarity of the magnetic flux is reversed, and an alternating voltage is induced in the detection coil wound around the center of the thin wire, and the rotation speed and rotation angle are detected from this alternating voltage. A plurality of detection elements each having a detection coil wound around the center are disposed, and the comrades on the armature side or the comrades on the armature side in the direction of rotation of the rotating magnetic pole plate in both ends of the thin wires of the plurality of detection elements are placed on the periphery of the rotating magnetic pole plate. The detection element has a resolution that can be obtained only from the number of magnetized magnetic poles because the magnetic flux distribution that changes sinusoidally along the axis is sequentially shifted at equal intervals in terms of phase within a width of 18o0. be increased several times. Furthermore, if a Co-based amorphous alloy is used, for example, the amount of deformation due to magnetization, that is, the amount of deformation due to magnetization, becomes almost zero, and the mechanical strength is also strong, so detection can be performed extremely stably. By making a thin wire with a diameter of about 50 = 120 um and winding a thin copper wire around the center of this thin wire to form a small detection element, it becomes possible to increase the resolution by arranging a large number of detection elements. .

〔Example〕

FIG. 1 is a side sectional view of one embodiment of a rotation detection device constructed based on the present invention, and FIG. 2 is a perspective view showing the principle of construction of the main parts of the device shown in FIG.

In these figures, 1 is a case of the rotation detecting device, and 2 is a rotating shaft having, for example, a keyway 2A for being integrated with a rotating body (not shown) at its tip, and is rotatably supported by the case 1. A rotating magnetic pole plate 3 made of a ferromagnetic material is fixed concentrically within the case 1. The peripheral edge of the zero-rotating magnetic pole plate 3 is magnetized with S and N poles alternately adjacent to each other at predetermined equal intervals. Along this peripheral portion, a spatial magnetic field is formed whose polarity changes in a substantially sinusoidal manner alternately in S and N directions. Figure 1.

FIG. 2 shows an example in which a resolution twice as many as the number of magnetized poles of the rotating magnetic pole plate is obtained, and two detection elements (4.5) are used. The detection element 4.5 has a detection coil 8.5 at the center of the amorphous alloy thin wires 6, 7 bent into a U-shape.
The thin amorphous alloy wire 6.7 of each detection element 4.5 is wound onto the case l via the supporting member 10.11 so that both ends of the thin amorphous alloy wire 6.7 are approximately parallel to the axial direction of the rotating shaft 2. is fixed. At this time, both ends of each detection element 4.5 are connected to the second
As shown in the figure, each thin wire end of the detection element 4 is N
When located at the center position of the pole and south pole, another detection element 5
The ends of each of the thin wires are placed on the boundary line between the S-N and N-3 poles, that is, so that they are out of phase by 90° in the let flux distribution. 12 is a detection circuit having a function of signal processing the induced voltage generated in the detection coil 8.9 as described later. 13
is a lead wire that transmits signals to the outside.

As the amorphous alloy thin wire 6.7, a Co-based amorphous alloy thin wire is passed. As mentioned above, Co-based amorphous alloy thin wires are mechanically strong and have almost zero magnetostriction, so thin copper wires can be added to thin wires with a diameter of about 50 to 120 mm without affecting the magnetic properties. It has the advantage of being able to be wound and making the detection element smaller, and has higher magnetic permeability in the high frequency range than magnetic materials such as permalloy and ferrite, and has excellent sensitivity to magnetic fields.
Also, compared to Hall elements and magnetoresistive elements, it has less dependence on ambient temperature. Hereinafter, the detection coil 8 of each detection element 4.5 will be described as the rotation of the rotating magnetic pole plate 3, that is, the passage of the magnetic pole.
．． The output obtained in Section 9 and its signal processing will be explained.

FIG. 3(a) is an example of the output waveform of the detection element 4.

When the waveform (a) is full-wave rectified by the detection circuit 12, the waveform (b) is obtained, and the period of the peak value is the same as the time interval between adjacent magnetized poles of the rotating magnetic pole plate. Detection element 5
In this embodiment, the output waveform of is obtained as a waveform whose phase is delayed by 90'' from that of the detection element 4, and when similarly full-wave rectified, it becomes as shown in FIG.

By adding the full-wave rectified waveform of the output of the rain detection element 4.5, a waveform with a frequency doubled for the number of magnetized poles is obtained, and this waveform is the reference voltage (■). If a pulse is generated when the number of magnetized poles is exceeded, it is possible to obtain a digital output value twice as many as the number of magnetized poles shown in (f), and the rotation angle can be detected with twice the resolution.

Figures 1 to 3 are examples in which double the resolution is obtained, but as the number of detection elements is increased, the phase shift of the output of the detection elements is made smaller than 90° (if this is done, the resolution can be further increased). Can be done.

[Effects of the Invention] As described above, according to the present invention, the configuration of the rotation detection device is such that magnetic poles of different polarities are arranged alternately along the circumference of the rotating shaft driven by the rotating body to be detected. Rotating magnetic pole plates arranged at equal intervals are fixed concentrically, and a detection coil is wound around the center of a ferromagnetic thin wire made of an amorphous alloy. A magnetic flux distribution that changes in a sinusoidal manner along the circumference of the magnetic pole plate is provided at intervals of an odd multiple of 180° at intervals of an odd number of times 180°, and the rotating magnetic pole plate rotates at both ends of the thin wires of the plurality of detection elements. Since the directional armature side comrades or the directional armature side comrades are sequentially shifted at equal intervals in phase within the 180° width of the magnetic flux distribution, the resolution for the rotation speed and rotation angle can be adjusted to the peripheral edge of the rotating magnetic pole plate. The resolution obtained only from the number of magnetic poles arranged at equal intervals along the detection element is increased by a factor of two.

In addition, by using a metal material such as a Co-based amorphous alloy thin wire, which is mechanically strong, has almost no magnetostriction, has high magnetic permeability in the high frequency region, and has excellent sensitivity to magnetic fields. A rotation detection device with a simple configuration that is not easily affected by ambient temperature, and has almost no change in magnetic properties due to deformation during magnetization, thus enabling stable detection, excellent high-speed response, and high zero resolution. can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of an embodiment of a rotation detection device constructed based on the present invention, FIG. 2 is a perspective view showing the principle of construction of the main parts of the device shown in FIG. 1, and FIG. FIG. 2 is a waveform diagram of a detected voltage and its processed voltage, showing a procedure for detecting a rotational speed and/or rotational angle by the apparatus of the invention. 2...Rotating shaft, 3...Rotating magnetic pole plate, 4.5...Detecting element, 6.7...Amorphous alloy thin wire, 8.9...Detecting coil Fig. 1 F, 25i ]

Claims (1)

[Claims] 1) A device for detecting the rotation speed and/or rotation angle of a rotating body, in which a rotating shaft driven by the rotating body has a rotating magnetic pole in which magnetic poles of different polarities are arranged alternately and at equal intervals along the periphery. The plates are fixed concentrically and a detection coil is wound around the center of a thin ferromagnetic wire made of amorphous alloy. 1 in wave-like magnetic flux distribution
The plurality of detection elements are arranged close to the peripheral edge of the magnetic pole plate at intervals of an odd number multiple of 80 degrees, and the comrades on the hand side or the side on the side of the rotating magnetic pole plate in the rotation direction of the rotating magnetic pole plate at both ends of the thin wires are arranged at intervals of 180 degrees of the magnetic flux distribution. A rotation detection device characterized in that the rotation detection device is arranged so as to be sequentially shifted at equal intervals in terms of phase within a width of .degree. to obtain a resolution that is an integral multiple of the number of magnetic poles of the rotating magnetic pole plate.