JPS6031005A - Detector of position of rotary angle - Google Patents

Abstract

PURPOSE:To detect the position of a rotary angle by a simple and compact constitution highly accurately, by detecting a voltage which responds to the change in magnetic flux in a sine wave shape, which is generated by a rotary magnet in thin plate shape, by two sets of Hall elements, which are provided at separated positions. CONSTITUTION:A rotary magnet 1 in a thin plate shape is rotated as a unitary body together with a rotary body. Two poles are a magnetized on the magnet so that the magnetic flux in the radial direction changes in the circumferential direction in a sine wave shape. Hall elements 6a and 6b, which are arranged at the positions separated by 90 deg., respond to the magnetic flux. Bias ACs Iosinwt and Iocoswt, whose phases are different by 90 deg., are applied to elements 6a and 6b. Then the sum V of the induced voltages, which are outputted from the elements 6a and 6b in correspondence with an angle theta with respect to the boundary of the magnetic fields N and S of the magnet 1, becomes V=KIoBosin (wt+theta), where K is a constant and Bo is magnetic flux. The angle theta is detected, and the position of the rotary angle is detected by the simple and compact constitution highly accurately.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] [Technical Background of the Invention and Problems Therewith] Conventionally, optical rotation angle position detection has been used to detect the rotation speed, rotation angle, rotation position, etc. of rotating machines. A rotation angle detector (hereinafter referred to as an optical detector), a rotating electric machine type rotation angle detector (hereinafter referred to as a rotating electric machine type detector) using electromagnetic induction, and the like are used.

An optical detector houses a disc that rotates with the shaft of a rotating machine and has thin slits formed at predetermined intervals on its circumference in a case that has a light-shielding structure. A light-emitting element and a light-receiving element are disposed facing each other with a slit in the plate interposed between them, and the light from the light-emitting element is blocked by the rotating slit and to thereby output a pulse from the light-receiving element side. This is what I did to get it. Since the disc with the slit in this optical detector can be thin, it can be made smaller and lighter. However, in order to avoid being affected by optical noise and ensure detection accuracy at a certain level, it is necessary to completely shut off the light between the case and the axis of the rotating machine. required high technical ability. In addition, disks are usually made of glass or the like in order to improve their characteristics, and because they have a large number of slits formed in them, they are weak in strength and have problems such as requiring careful handling during fabrication and operation. there were.

On the other hand, in a rotating electric machine detector, for example, in the case of a resolver, first and second stator windings are wound around a stator, and a rotor winding for detection is wound around a rotor. A high frequency voltage is applied to the first and second stator windings, and the rotor winding outputs a voltage proportional to the rotation angle.

In this case, conventionally the output of the rotor winding was taken out to the non-rotating side by means of brushes, but due to reasons such as lowering reliability, recently it has been taken out by means of a rotating transformer. I try to take it out on the non-rotating side. In such a configuration,
Since it is configured as a rotating electric machine, the stator and rotor are
It requires a certain size or more, so it is likely to be larger than the optical detector described above, and the winding process requires a large number of man-hours. was there.

1 [Object of the Invention] The present invention has been made based on the above-mentioned circumstances, and its object is to provide a rotation angle position detector which is small in size and has a simple configuration and is capable of detecting the rotation angle of a rotating shaft with high precision. It is about providing.

[Summary of the Invention] In order to achieve the above object, the rotational angular position detector according to the present invention is characterized by being configured as follows. That is,
A thin plate-shaped rotating magnet that generates a sinusoidal change in magnetic flux from the center toward the periphery due to rotational movement is provided on the rotating shaft whose rotational angle is to be detected, and at least one magnet is biased by a high-frequency sinusoidal current. 1. The second Hall elements are disposed at a distance from the center toward the periphery of the rotating magnet and spaced apart from each other in order to output voltages in response to the sinusoidal magnetic flux changes. The structure is as follows.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
1 and 2 show an embodiment of the rotational angular position detector according to the present invention, FIG. 1 is a configuration diagram seen from the front direction, and FIG. 2 is a sectional view seen from the side direction.

In FIGS. 1 and 2, reference numeral 1 denotes a bipolar thin disc-shaped rotating magnet that is attached to the shaft 2 of a rotating electric machine during a show session via a substantially cylindrical fitting member 3.

This rotating magnet 1 is manufactured by magnetizing a thin disc-shaped magnetic body so that the magnetic flux across the circumference and radially changes in a sinusoidal manner. Reference numeral 4 denotes a stay that has an inner diameter larger than the outer diameter of the rotating magnet 1 by the amount t shown in the drawing, and is formed with first and second convex portions 5h and 5b spaced apart by 90° from the center. 6a and 6b are the convex portions 5&.

Hall elements gx and g2 are arranged so that their magnetic field sensitive surfaces are parallel to the plane 5b.

As shown in FIG. 3, the Hall elements 6m and 6b apply a current bias of current value I to their input ends, and when a magnetic flux B is applied in a direction perpendicular to the direction in which this current flows, the current ■ and the magnetic flux B The voltage V=KBI(K
ld (referred to as sensitivity and is a constant) is generated. Note that the voltage V is proportional to the magnetic flux B as shown in FIG. In addition, such Hall elements 6* and 6b have been recently available, and have high output and
Products with high characteristics such as high heat resistance and small drift are manufactured, and the quality is uniform for each product.

Next, the operation of this embodiment configured as described above will be explained with reference to FIG. FIG. 5 is a diagram schematically showing the embodiment shown in FIGS. 1 and 2.

In FIG. 5, alternating currents Ia=Icoogω3 Ib=Iomωt as shown in FIGS. 6(a) and (b) are supplied to the input terminals of the first and second Hall elements 6h and 6b, respectively. It is assumed that the rotary magnet 1 is rotated around the shaft 2 many times and the second Hall element 6b is positioned at an angle θ with respect to the boundary of the magnetic poles, as shown in FIG. In this state, the first
On the magnetic field sensitive surfaces of the second Hall elements 6h and 6b, a magnetic field Ba = Bostn as shown in FIGS. 6(c) and 6(d) is applied.
θ, Bb = Bocos θ acts. As a result, from the output ends of the first and second Hall elements, an AC voltage Va=K-Ia4a=4oBocosωtsfnθ, and Vb=KIbBb=-Io-Boslnωt・cosθ are output. . The sum V of the output voltages of the first and second Hall elements 6a and 6b is as follows: V=Va+Vb=K HI o −B o −cm (
d t-tAnθ10K・I 0-Bo bite Q) t −
asθ=−IO−Bo−gin(ωt+θ).

This sum voltage V is shown in FIG. 6(d). When the sum voltage V=-I o -B osin (ωt+θ), the rotational position of the rotating magnet 1, that is, the angle θ can be detected.

As described above, in this embodiment, the rotational position can be detected in the same manner as the rotating electrical machine type detector. In addition, the rotating magnet 1, which is a rotating body, can have a small thickness, and the first and second Hall elements 6a and 6b, which are detection elements, are small elements, and the rotating magnet 10 turns around 10 times. Since the device is installed in the same direction, the external dimensions of the entire device can be significantly reduced. Furthermore, since no pre-emptive structure is required, processing and assembly of the parts are easy and inexpensive.

The above configuration is an example implemented as a separate configuration from a rotating machine, but for example, as shown in FIG. 7, the structure shown in FIG. It is also possible to adopt a configuration in which the rotating shaft 90 and the rotating magnet 1 are attached as in FIG. 2, and the Hall elements 6m and 6b are provided on the frame 8. With such a configuration, it is possible to obtain a rotating electric machine 7 that includes a motor section and a detection section and has an extremely small dimension in the axial direction.

This configuration is especially useful for machine tools that require downsizing.
It is effective if applied to servo motors such as G and G. In addition, conventional optical and rotating electric machine type detectors have a configuration in which multiple connections are made to the rotating electric machine to be detected by force and pull, so they are susceptible to resonance (due to wide range speed changes) and especially to the rotating electric machine type. However, in the above configuration, the rotating magnet 1 is directly attached to the rotating shaft 9 of the rotating electrical machine 7 to be detected, so Problems associated with speed changes and force and pull connections do not occur. Furthermore, since the rotating magnet 1 and the coil elements 6h+6b are housed within the frame 8, they are reliably protected.

In the above embodiment, the rotating magnet 1 rotates one rotation of the disk (
360') was implemented as a bipolar type divided into two parts, but the invention is not limited to this. The circumference of the disk-shaped ferromagnetic material is divided by the axial angle multiplier n1 electrical angle by θn, and the For each divided part, there are n-poles (n
may be an integer).

In this case, the relationship θ=nθm holds true, and the output voltage V is v
= to -IO-Bo11flI(ωt-nθm),
The resolution per rotation of the rotating magnet can be made finer.

FIG. 8 shows the waveform of the output voltage V when n=2 and n=5.

Note that the present invention is not limited to the above embodiments,
For example, various methods can be used as appropriate, such as the means for connecting the rotating magnet and the shaft to be tested, the method for arranging the rotating magnet and the pole element, and the method for processing the output voltage from the Hall element. In addition, the present invention can be modified in various ways without departing from the spirit thereof.

9- [Effects of the Invention] As described above, according to the present invention, a thin plate-shaped rotating magnet provided on a rotating shaft and rotating integrally generates a magnetic flux that changes sinusoidally in the direction of the peripheral edge. The magnetic flux is biased by a high frequency sinusoidal current, and the magnetic flux is biased by at least first
, the second Hall element is caused to emit a voltage, the sum or difference of these two voltages is determined, and the rotation angle of the rotation axis is detected from the phase difference between them. Therefore, it is possible to provide a rotation angle position detector that is small in size and has a simple configuration, and is capable of detecting rotation angles with high precision.

[Brief explanation of drawings]

1 and 2 show an embodiment of the rotational angular position detector according to the present invention. FIG. 1 is a configuration diagram seen from the front, and FIG. 3 is a schematic diagram for explaining the characteristics of the Hall element, FIG. 4 is a characteristic diagram of the Hall transducer, and FIG. 5 is a diagram showing the tenth embodiment shown in FIGS. FIG. 7 is a sectional view showing an application example in which the embodiment is incorporated into a rotating electrical machine. FIG. 8 is a waveform diagram for explaining another embodiment of the present invention. . 10.・Rotating magnet, 2... Shaft, 3... Fitting member, 4
... slur, 5 m, 5 b-convex part, 6 m,
6 b - Hall element. Applicant's agent Patent attorney Takehiko Suzue 11- Figure 5 Figure 6 io ---- l ' a ' wt (a) ・ 1 1111 1-+ ' 1 ' II 11' (b) ' + wt 11 1 +, 1 l l. +" l l' (C) " 1 l l + l " Mr. -f-l + ' 11 (d) 1 "'1 11 Wt 1 1 1 1 Fig. 7

Claims (1)

[Claims] A thin plate-like rotating magnet that generates a sinusoidal magnetic flux change from the center toward the periphery due to rotational movement is provided on the rotating shaft, and at least first and second Hall transponders biased by a high-frequency sinusoidal current are attached to the periphery. Rotational angular position detectors arranged at a distance in the direction of the parts and spaced apart from each other.