JPS60168018A - Position detecting device - Google Patents

Abstract

PURPOSE:To fetch a detecting signal of a stable waveform by constituting a rotating detecting body of a position detecting device of a magnetic material, and providing at least one projection on the outside peripheral part of its detecting body. CONSTITUTION:A rotation detecting body 21 rotating coaxially a rotating body to be measured (not shown in the figure) is constituted of a magnetic material, and this detecting body 21 is constituted in a shape of a gear by forming a lot of projections 22a, 22b... on its outside peripheral part. A magnetism detecting mechanism 23 is provided oppositely so as to be fixed through a gap (g) on the outside peripheral part of this gear-shaped rotation detecting body 21. This magnetism detecting mechanism 23 is provided with a substrate 24 of a nonmagnetic material, whose tip is turned to an axial core part of the rotation detecting body 21, and a magnetism detecting element 11 on which a pattern by a ferro-magnetic magneto-resistance material is formed so as to become a stage opposed to the projections 22a, 22b... by the gap (g) is installed and set to one surface of this substrate 24, and set to a state that a magnetic resistance is controlled variably against a passage of the projections 22a, 22b....

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a position detection device constituting a rotation detection device or the like that magnetically detects, for example, the rotation speed, rotation angle, etc. of a rotating body.

[Technical Background of the Invention] Conventionally, rotation detection devices using magnetic detection elements formed with patterns made of ferromagnetic magnetoresistive materials have been known.

For example, N1-co, Ni-Fe, etc. are used as the ferromagnetic magnetoresistive material constituting this magnetic detection element, and it is possible to form a resistor pattern on the insulating substrate surface using such ferromagnetic material. The magnetic detection element is configured by: Here, this pattern is constructed in the form of a folded line in which a plurality of long sides and short sides are sequentially connected, and by connecting two sets of patterns in which the directions of the long sides are set at right angles to each other through a bridge, the detection element is is composed of

FIG. 1 shows the configuration of a conventional rotation detection device constructed using such a magnetic detection element 11, in which a disk-shaped rotation detection device 12 is rotated coaxially with a rotating body whose rotational speed is to be detected. is constituted by a multipolar magnet whose outer circumferential portion is magnetized to N and S poles at equal intervals, and the magnetic detection element 11 is fixedly set close to the outer circumference of the rotation detecting body 12. It is something. That is, each time the rotation detecting body 12 rotates and its m-type portion passes close to the magnetic detecting element 11, the resistance value of the resistor pattern on the ferromagnetic material of the magnetic detecting element 11 changes, and the above-mentioned magnetic pole The state is such that a voltage signal corresponding to the passage of the rotation detector 12 is generated, and by processing this detection signal, the rotation speed of the rotation detector 12, etc. can be detected and measured.

FIG. 2 shows the state of the detection signal taken out from the magnetic detection element 11 of the detection device as described above, and this detection output voltage changes in response to changes in the rotation angle of the rotation detection body 12. . The thus detected signal is then used by setting a specified voltage level and comparing it with the set voltage level, and shaping the waveform into a rectangular pulse-like signal.

[Problems with blue technology]However, in a rotation detection device having such a configuration, the accuracy of the magnetization pitch of the multipolar magnet constituting the rotation detection body 12,
The output voltage of the magnetic detection element 11 changes as the magnetization strength etc. of the magnetic detection elements 11 and 2 vary. Therefore, the output signal with the period shown in FIG. 2 is (9
However, if this signal is waveform-shaped and converted into rectangular wave No. 13, the duty of this rectangular wave signal will vary. This results in a large static increase in order to perform high-precision rotation detection, and it becomes particularly difficult to perform high-precision detection of the rotary table.

Therefore, in order to perform high-precision measurements, it is necessary to make the magnetization state of the multipolar magnet that constitutes the rotation detection body 12 sufficiently high precision. The combination with multi-pole magnets has a large effect on cost.

[Purpose of the Invention] The present invention has been made in view of the above points, and provides a method for processing a detection signal from a magnetic detection element, particularly when shaping the waveform into a rectangular wave, so that the duty is always set in a stable state. It is an object of the present invention to provide a position detection device, such as a rotation detection device, in which the detection accuracy can be easily and reliably improved.

[Summary of the Invention] However, the position detection device according to the present invention is configured such that, for example, the rotating detection body is made of a magnetic material, and a protrusion of at least 1 g is formed on the outer periphery of the detection body. Then, a magnetic detection element is placed on one surface of a non-magnetic substrate fixedly set close to the outer periphery of the detection object, and the projection surface covers the magnetic detection element on the other surface. The magnet is attached and set in such a manner that the magnetic detection u1 structure is constructed.

[Practical Example of the Invention j An embodiment of the present invention will be described below with reference to the drawings. 3 and 4 show the configuration of a rotational speed detection device, in which a rotation detection body 21 rotated coaxially with a rotating body to be measured (not shown) is made of a magnetic material. The rotation detecting body 21 has a large number of protrusions 22a1221), . Then, the magnetic detection element 23 is fixedly set so as to be opposed to the outer circumference of the gear-shaped rotation detection body 21 with a gap g interposed therebetween.

This magnetic detection element 23 is equipped with a non-magnetic substrate 24 whose tip is directed toward the axis of the rotation detection body 21. On one surface of this substrate 24, a gap 9 is formed between the protrusions 22a and 22a.
, 22b, . Corresponding protrusions 22a, 221
) , . .

Further, on the other surface of the substrate 24, a magnet 25 is attached so that an N pole and an S pole are set along a line connecting the substrate 24 and the rotation detecting body 21. . In this case, the size of the magnet 25 is set so that its projected surface is larger than the resistor pattern of the magnetic detection element 11, and the substrate 24 on which the magnet 25 and the magnetic detection element 11 are attached has a tip portion thereof. The magnetic detection element 11 and the magnet 25 are shaped into a tapered state to become narrower.
The two sides are set to face each other at an angle θ. Here, the shortest distance C between the magnetic detection element 11 and the magnet 25 is 1~
The size is 4ml, and the gap Q is 5mm.
Set it to the following state.

In other words, in the rotation speed detection device configured as described above, as the gear-shaped rotation detection body 21 rotates, its protrusions 22a, 22b, . . .
3, the resistance value of the magnetic resistance pattern of the magnetic detection element 11 changes, and in response to this resistance change, the resistance value of the magnetic resistance pattern of the magnetic detection element 11 changes.
A detected output voltage signal having a waveform as shown in the figure is now extracted.

In this case, a constant magnetic field is always applied to the magnetic sensing element 11 by the 1i11 stones 25, and the strength of the magnetic field acting on the magnetic sensing element 11 is
It is variably controlled depending on the proximity state of the protrusions 22a, 22b, . . . made of magnetic material, and a detection voltage signal as shown in FIG. 5 is output. Therefore, since the magnetic field strength acting on the magnetic detection element 11 is constant, the output signal obtained from the magnetic detection element 11 is stabilized, and the output waveform is also stabilized. 17. In other words, even if this output waveform is shaped and converted into a rectangular wave signal, the duty will be a high m degree specified with respect to the rotation angle of the rotation detector 21, and the rotation angle detection accuracy will be extremely stable. It is something that can be converted into

FIG. 6 shows the relationship between the angle θ of the tapered portion formed at the tip of the base 24 to which the magnetic detection element 11 and the magnet 25 are attached, and the output signal level from the magnetic detection element 11. It is effective to set it to about 5 to 60'.

The magnet 25 may be configured to cover the range of the magnetic detection element 11 by itself as shown in the above embodiment, but as shown in FIG. The yoke 2 is made of a material with high transmittance (δ) for one side of the
G may be attached so that the yoke 2Ge a lν acts as a magnet. In this case, it goes without saying that yokes may be formed for both the N and S poles of the magnet 25, respectively.

In addition, when the rotation detection body 21 generates a large number of signals during one rotation, it is possible to configure the rotation detection body 21 in the shape of a gear as shown in the above embodiment. In order to detect the angular position, as shown in Fig.
It is sufficient if the configuration is such that one protrusion 28 is formed on the disk-shaped rotating body 27. In the case of such a detection device, the above-mentioned effect of being able to stably set the duty ratio of the sea urchin detection signal works more effectively to improve the detection accuracy of the rotation angle. .

In the above embodiment, a device for detecting rotational speed, etc. was used as an example, but such a device can also effectively constitute a linear position detecting device, for example, as shown in FIG. −
The moving detection body 29 is made of a magnetic material, and a protrusion 30 is formed on the detection body 29, so that the surface having the protrusion 30 passes close to the fixed magnetic detection mechanism 23. 1 is sufficient.

However, in the device configured in this way, the output signal from the detection mechanism is changed (in a warped state) corresponding to the state in which the protrusion 30 of the moving detection body 29 passes closest to the detection mechanism 23. This makes it possible to effectively detect the movement position of the movement detecting body 29.

In addition, in the apparatus shown in FIG. 9, the detection object 29 is fixedly set, and the magnetic detection mechanism 23 is attached to a moving object (& if the object is the detection object). The state of passing through the protrusion 30 portion of 29 can be detected at i''s fi degrees.

[Effect of Zataki] As described above, according to the present invention, there is no need to form 11 poles on the detection object, and the magnetic sensing element constructed using the ferromagnetic magnetoresistive material Stable against [
By making the 1st world work all the time, it becomes better. Also,
The above-mentioned detection body can also be constructed by simply adding a magnetic material, and with a sufficiently simplified configuration, a pressure detection signal with a stable waveform can be extracted from the magnetic detection element.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram illustrating a conventional detection device, FIG. 2 is a diagram illustrating an output signal waveform from the device, and FIG. 3 is a front view illustrating the configuration of a rotation detection device according to an embodiment of the present invention. FIG. 4 is a configuration diagram of the device shown in FIG. 3 as seen from the side, FIG. 5 is a diagram showing the output waveform of the above detection device, and FIG. 6 is a diagram showing the taper of the substrate in the above device. 7 is a configuration diagram illustrating another example of the magnetic detection mechanism, and FIGS. 8 and 9 are configuration diagrams illustrating still other embodiments of the present invention. It is a diagram. 11... Magnetic detection element, 21... Rotation detection body, 22
a, 22b,...28.30...protrusion, 23...
Magnetic detection mechanism, 24... Substrate (non-magnetic material), 25...
- Magnet, 2G... Yoke, 29... Moving detection object. Applicant's Representative Patent Attorney Takehiko Suzue Figure 1 Figure 2 Figure 3 Figure 4 ft55 Figure 6 Figure 7 Figure 8

Claims (2)

[Claims] (1) Mounted on one side of a detection body having at least one magnetic protrusion and a substrate made of a non-magnetic material fixed close to the moving surface of the protrusion of the detection body. is characterized by comprising a set magnetic detection element, and a magnet set to be attached to the other surface of the substrate so that a projection surface for the magnetic detection element covers the magnetic detection element portion. position detection device. (2) The position detection device according to claim 1, wherein the magnet is constituted by a permanent magnet and a yoke formed on at least one magnetic pole of the permanent magnet.