JPH03191817A - Magnetic encoder - Google Patents

Abstract

PURPOSE:To improve the reliability of an encoder by providing a plurality of magnetoresistance elements in first - fourth phases which are formed at the pitch of a specified pole width. CONSTITUTION:This apparatus has a plurality of magnetoresistance elements 5'A, 5'A11 - 5'A14... in the first phase which are formed at the pitch of the pole width of about lambda/2 along the movable direction of a multipolar magnetic body and elements 5'B, 5'B11 - 5'B14... in the second phase so that the phase of about lambda/8 is shfted along the moving direction of the multipolar magnetic body from the elements 5'A, 5'A11 - 5'A14.... Elements 5'C, 5'C11 - 5'C14... in the third phase are formed at the pitch of the pole width of about lambda/4 from the first elements 5'A, 5'A11 - 5'A14.... Elements 5'D, 5'D11 - 5'D14... in the fourth phase are formed at the pitch of the pole width of about lambda/8 from the third elements 5'C, 5'C11 - 5'C14.... When the elements in first - fourth phases are provided in this way, the reliability of an encoder can be improved.

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a magnetic encoder using a movable element having magnetic encoder magnetic poles and a magnetoresistive element, and is particularly applicable to limited Concerns a possible magnetic encoder that uses magnetic encoder magnetic poles with a multi-pole number of magnetization poles and makes it possible to extract more magnetic encoder signals, and is applicable to either rotary type or linear type magnetic encoders. It is something that has.

[Prior Art] When performing positioning in various automatic devices, a means is required to measure the rotation angle and movement amount of a motor, etc., and to convert these into electrical signals. For this purpose, devices called encoders are often used.

For example, rotary encoders are divided into incremental types that measure the number of pulses generated with one rotation, and absolute types that generate an absolute value signal of the position at which the code recorded on the rotor is read. be. In addition, the detection method includes
There are optical and magnetic encoders, but recently, incremental magnetic encoders, which are inexpensive and highly reliable, have come into widespread use.

Figure 7 shows a conventional general rotary magnetic encoder 1.
In the explanatory diagram, there are 2N N poles on the outer circumference, each with a magnetic pole width of approximately λ,
A magnetoresistive element (
MR sensors) 5 are arranged facing each other. The magnet rotor 3 may be an integral type made of a resin magnet, or may be formed by coating a magnetic layer on the outer periphery of a suitable rotor drum.

The N pole 2N and S pole 2S of the magnetic encoder magnetic pole 2 are magnetized to have a width of approximately λ (equal to the width expressed by 2π in electrical angle).

In addition, the magnetoresistive element 5 is assumed to be a ferromagnetic magnetoresistive effect element, for example. First, in order to explain the principle of the magnetic encoder 1, it is a wire formed of a ferromagnetic thin film that constitutes the magnetoresistive element 5. The magnetoresistive element 6 will be explained using FIG. 8.

This magnetoresistive element 6 is made of Ni--Co and has a thickness of approximately several thousand angstroms.

The magnetoresistive element 5 can be formed by forming a Ni-Fe metal thin film (ferromagnetic metal thin film) on a substrate such as glass by means such as vacuum deposition or etching.

As shown in FIG. 8, when the magnetoresistive element 6 is arranged so that the direction of the current (2) flowing through it and the magnetic field 7 are perpendicular, the magnetic field 7 will move from the north pole 2N to the south pole 2S.

As shown in FIG. 9, this magnetoresistive element element 6 causes a decrease in resistance value due to a horizontal magnetic field 7X within a magnetic field 7. Note that 7Y indicates a vertical magnetic field.

At this time, the rate of change in resistance of the magnetoresistive element 6 is several 7%, and when the width of one magnetic pole of the magnetic encoder magnetic pole 2 is λ, the resistance value of the magnetoresistive element 6 at the position of λ/4 If the change value of R1 resistance is Δr, then the resistance at the phase θ of the magnetic pole (2N or 2S) and the magnetoresistive element 6 (−phase θ when the magnetic pole widths 2N and 2S are respectively 2π in electrical angle) The value R(θ) is.

R(θ)=IR+ −Δr −cosθ (1)
It can be expressed as

The lateral magnetic field 7X is related to two phases θ and the distance between the magnetoresistive element 6 and the magnetic encoder magnetic pole 2, and the magnetoresistive element 6 also takes a resistance value R corresponding thereto.

In the case of the magnetoresistive element 5, unlike other magnetic sensors such as Hall elements, there is no lateral magnetic flux at the center of the magnetic field (the magnetic field state at the middle of the north pole 2N and the south pole 2S), so the output is It has the characteristic that the signal does not change.

Since it is not possible to obtain the A-phase and B-phase magnetic echoer signals with the magnetoresistive element 5 having the single magnetoresistive element 6 described above, the four magnetoresistive elements 6 as shown in FIG.
Book magnetoresistive element Niremen) 6a, 6b, 6a', 6
b' are sequentially shifted by approximately λ/4,
A-phase and B-phase magnetic encoder signals are obtained.

This magnetoresistive element 5 includes two magnetoresistive element elements 6a and 6a' for obtaining an A-phase magnetic encoder signal, and two magnetoresistive element elements 6b and 6b' for obtaining a B-phase magnetic encoder signal. It has become a thing.

When the width of one magnetic pole (N pole 2N or 5i2S) of the magnetic encoder magnetic pole 2 is ^ (2π in electrical angle), the magnetoresistive elements 6a and 6a' have opposite phases to each other.
They are formed to be shifted by /'2 width.

Similarly, the magnetoresistive elements Niremen l-6b and 6b' are
They are formed to be shifted by ^/'2 width so that they are in opposite phases to each other.

Further, the magnetoresistive element elements 6a and 6b, and 6a and 6I:1 are formed to be shifted from each other by a width of λ/'4.

Therefore, one magnetoresistive element 5 has magnetoresistive element elements 6a and 6b sequentially shifted by λ/11 pitch.

6a and 6b' are formed.

As a circuit for processing the magnetic encoder signal from the magnetoresistive element 5 formed in this manner, a circuit 1 as shown in FIG. 11, for example, is used.

This magnetic encoder signal processing circuit 8 includes resistors 9-1.
..., 9-4 constitutes a bridge and converts the resistance change into a voltage change, and the comparators 10-1 and 10-2 convert the 90" phase as shown in FIGS. 12(a) and (b). Two different square wave magnetic encoder signals 11-1°1
I'm trying to get 1-2.

This square wave magnetic encoder signal 11~1°] -1, -
2 by a counter, the rotation angle of the magnetic encoder can be measured.

[Problems to be Solved by the Invention] In order to increase the resolution by one point in a magnetic encoder as described above, the magnetization pitch of the magnetic encoder magnetic poles must be made extremely fine.

The finer the magnetization pitch, the more difficult it is to achieve fine magnetization and the more difficult it is to manufacture.

The rotor diameter had to be enlarged. Furthermore, the air gap must be narrowed in accordance with the magnetic pole width, requiring highly accurate bearings, and there is a risk of damage due to vibration or the like.

Note that in order to increase the resolution, the magnetization pitch of the magnetic encoder magnetic poles must be made extremely fine, but the finer the magnetization pitch, the more the distance between the magnetoresistive elements of the magnetoresistive element becomes. This makes it difficult to manufacture products of constant quality with good yields.

Further, in the magnetic encoder 1 as described above, the magnetoresistive element 5 used therein is configured so as to be able to obtain two-phase magnetic encoder signals for the A phase and the B phase, which are shifted by 90 degrees from each other in phase angle. has been done. Further, in order to configure a highly accurate magnetic encoder signal, a plurality of magnetoresistive elements for each phase are usually formed.

In the case of such conventional magnetic encoders, in order to configure a magnetic encoder with a resolution higher than 2, it was necessary to configure a multiphase magnetic encoder by arranging a plurality of magnetoresistive elements adjacent to each other with their phases shifted from each other. However, in the case of a constant rotor diameter, in order to make the magnetic encoder signal obtained from the magnetoresistive element multiphase, it is difficult to arrange a large number of magnetoresistive elements along the circumferential direction. The magnetoresistive element itself is large, and the shape of the rotor is inconvenient, making it difficult to easily form a high-quality one at low cost.

[Problem to be solved by the invention] The present invention has been made in view of the above circumstances.

Magnetic encoder with multi-pole magnetization on the surface The magnetic poles are magnetized with a width that maintains reliability1.For example, in the case of a rotary magnetic encoder, it is possible to increase the diameter of the magnet rotor and to arrange multiple sets of magnetic resistance elements along the circumferential direction. Therefore, it is possible to form a magnetoresistive element that can obtain a 4-phase magnetic encoder signal that can be constructed with a narrow width, and use this 4-phase magnetic encoder signal as it is as a 4-phase signal, or to use this 4-phase magnetic encoder signal as a 4-phase magnetic encoder signal. The object of the present invention is to obtain a highly reliable high-resolution magnetic encoder extremely easily and inexpensively by extracting a two-phase magnetic encoder signal with a 90" phase difference by making full use of known waveform shaping and logic circuits. It is something that

[Specific Means for Achieving the Problems of the Invention] The problem of the present invention is to provide a plurality of first phases formed at a pitch of approximately λ/4 magnetic pole width along the movable direction of the multipolar magnetic pole body. A magnetoresistive element group and a magnetic field forming a second phase formed by shifting the phase by approximately λ/8 pitch from each of the first phase magnetoresistive element groups along the moving direction of the multipolar magnetic pole body. and resistance element element group.

A plurality of magnetoresistive elements for forming a second phase formed from each of the magnetoresistive element element groups of the first phase at a pitch of approximately λ/4 magnetic pole width along the moving direction of the multipolar magnetized body. a plurality of elements for forming a fourth phase formed at a pitch of approximately λ/8 magnetic pole width along the moving direction of the multipolar magnetized body from each of the magnetoresistive element group of the third phase; This can be achieved by using a magnetoresistive element consisting of a group of magnetoresistive element elements.

[Function] The magnetic encoder having the magnetoresistive element of the present invention can obtain four-phase magnetic encoder signals from the magnetoresistive element disposed opposite to the magnetic encoder magnetic poles of the magnetic encoder with relatively low resolution. It is possible to construct a magnetic encoder with twice the resolution compared to the magnetic encoder of . These four-phase magnetic encoder signals can be further improved in resolution by shaping and multiplying the waveform using, for example, the cheapest known doubling circuit. If you use an inexpensive n-multiplier circuit that makes full use of the It can be configured extremely easily.

Since the magnet rotor requires only low-resolution multi-pole magnetization, the distance between the magnetic poles can be large. For example, regarding a rotary type magnetic encoder, if the resolution is the same, a small diameter magnet rotor can be used, so it can be mass-produced in a small size and at low cost. High-quality items can be manufactured easily. In particular, in the case of a rotary magnetic encoder, in order to arrange multiple sets of multiple magnetoresistive elements in the circumferential direction, the outer periphery of the magnet rotor is arcuate, so a wide one is required to match the arc. However, it is difficult to form and arrange it as a single element.

Since it can be constructed as a single narrow magnetoresistive element that can obtain four-phase magnetic encoder signals, it is also extremely easy to form the lead-out terminal portion of the element.

In addition, in the case of a normal two-phase magnetic encoder, if one phase fails for some reason, encoder signals in the forward and reverse rotation directions cannot be detected, but in the present invention, the four-phase magnetic encoder signal Since it is based on
By making it possible to perform discrimination based on adjacent digital encoder signals, it is possible to obtain a magnetic encoder that is advantageous in terms of reliability.

[One Embodiment] The present invention is also applicable to a linear magnetic encoder, but since the description will be redundant, in the second embodiment shown below, a rotary magnetic encoder will be described.

FIG. 1 shows an incremental type magnetoresistive element 5 of the present invention.
A perspective view of a rotary magnetic encoder 1' using
FIG. 2 shows the magnetic encoder l.

Fig. 3 is an enlarged explanatory view of the magnetoresistive element 5' used in the above, and Fig. 3 is an expanded view of the magnetic encoder magnetic pole 2 and the magnetoresistive element group of 1° of the magnetoresistive element, and Fig. 4 is an enlarged view of the magnetoresistive element element group. FIG. 5 is a circuit diagram of an n-multiplying circuit including a waveform shaping circuit, and FIG. 6 is a waveform diagram of each part.

Referring to FIG. 1, similarly to the conventional general rotary magnetic encoder 1, there are 2N N poles on the outer periphery with a magnetic pole width of approximately λ.
, a magnet rotor 3 having a magnetic encoder magnetic pole 2 in which magnetic poles of S poles 2S are alternately magnetized at fine pitches at equal intervals.
Magnetoresistive elements (MR sensors) 5' are disposed facing each other with a radial gap 4 interposed therebetween to form an incremental magnetic encoder 1'.

The magnetoresistive elements 5° include a Z-phase (origin) first magnetoresistive element 5'-1 on an insulating substrate 12 made of glass or the like in order from above.
and a second magnetoresistive element 52 from which first to fourth phase magnetic encoder signals are obtained. The second magnetoresistive element 5°-2 from which the magnetic encoder signals of the first to fourth phases are obtained is a plurality of magnetoresistive elements 5°A (hereinafter referred to as A-phase magnetoresistive element element 5) constituting the first phase. 'A
), a plurality of magnetoresistive elements 5' constituting the second phase.
B (hereinafter referred to as B-phase magnetoresistive element element 5°B)
, a plurality of magnetoresistive elements 5°C constituting the third phase (hereinafter referred to as C-phase magnetoresistive element elements 5'C) and a fourth
It consists of a plurality of magnetoresistive elements 5°D (hereinafter referred to as D-phase magnetoresistive element elements 5'D) that constitute the phase.

Referring to FIGS. 2 and 3, the magnetoresistive element 5' includes a Z-phase (origin) first magnetoresistive element 5"-1 formed on the upper part of the insulating substrate 12, which is approximately λ magnetic pole The Z-phase magnetoresistive element element 5'Z+t and the two-phase magnetoresistive element element 5'Z1□ are formed with a width phase shift (however, not shown in FIG. 3). The upper end of each of the magnetoresistive element elements 5' Z++ and 5° 212 is electrically connected to the power terminal 1. ground terminal G formed at the lower end of the insulating substrate 12, respectively, via connecting conductive wires 13 and 14. The lower ends of the Z-phase magnetoresistive element elements 5'Z11 and 5'Z1□ are commonly connected via a connecting conductive wire 16, and are connected to the lower ends of the insulating substrate 12, respectively. It is connected to the connection terminal Zll.

The A-phase magnetoresistive element 5'A forming the second magnetoresistive element 5'-2 is the single-phase magnetoresistive element 5'A.
'A
Phase magnetoresistive element 5' A 12.5'
A I3 and 5'A□4 are formed by a total of four A-phase magnetoresistive element elements 5'A11 to 5°A14.

The B-phase magnetoresistive element element 5'B forming the second magnetoresistive element 5'-2 is the A-phase magnetoresistive element element.
Sequentially from 5'A++ to 5°A+4, the phase is shifted in the circumferential direction (to the right in FIGS. 2 and 3) by approximately λ/4 magnetic pole width, and the B-phase magnetoresistive element element 5'B1□,
1 by forming 5'B+□, 5'BI3 and 5'B+a
Total of 4 B phase magnetoresistive element elements 5'B++~5
'It is formed in B14.

The C-phase magnetoresistive element 5'C forming the second magnetoresistive element 5'-2 is the 9-phase magnetoresistive element 5.
From °A11, the phase is shifted in the circumferential direction (to the right in Figures 2 and 3) by approximately λ/4 magnetic pole width.
Phase magnetoresistive element elements 5'CI2.5''CI3 and 5'CI4 are formed, and a total of four C-phase magnetoresistive element elements 5''C1□ to 5'C14 are formed.

The D-phase magnetoresistive element 5'D forming the second magnetoresistive element 5°-2 is the C-phase magnetoresistive element
5"C1□ to 5'C14, the phase is shifted in the circumferential direction (rightward in the drawings of FIGS. 2 and 3) by approximately λ/4 magnetic pole width, and the D-phase magnetoresistive element element 5'Dol
, 5'CI2.5' Dis and 5' DI4 are formed to form a total of four D-phase magnetoresistive element elements 5'D1.
It is formed from 1 to 5'DI4.

That is, in the magnetoresistive element of the present invention, the A-phase magnetoresistive element elements 5 are sequentially arranged with a phase shift of about λ/4 magnetic pole width, respectively.
'A+1. C-phase magnetoresistive element 5' C1,
, B-phase magnetoresistive element element 5'B port, D-phase magnetoresistive element element 5'Dll, A-phase magnetoresistive element element 5' A I2+ C-phase magnetoresistive element element 5
°C, 2, B-phase magnetoresistive element 5' B12.
D-phase magnetoresistive element 5'D1□, A-phase magnetoresistive element 5'A, , C-phase magnetoresistive element 5'Cts, B-phase magnetoresistive element 5'B
131 D-phase magnetoresistive element 5'D13. A
Phase magnetoresistive element element 5' A 1a, C phase magnetoresistive element element 5C, 4, B phase magnetoresistive element element 5'B, 4. D-phase magnetoresistive element 5'D
, 4 are formed.

A-phase magnetoresistive element 5'A++, C-phase magnetoresistive element 5'C, , B-phase magnetoresistive element 5°B, , D-phase magnetoresistive element 5'D+
+, A-phase magnetoresistive element element 5''A, 2. C-phase magnetoresistive element element 5' CI2. B-phase magnetoresistive element element 5'B1□, D-phase magnetoresistive element element 5
'The upper end of each D+2 is.

Connection conductive wires 17, 18, 19, 20.2122.23.
Connection terminals A, C, B, D are formed on the lower end of the insulating substrate 12 via 24.

A2. C2, B2. Connected to D2.

Also, A-phase magnetoresistive element element 5''A, , C-phase magnetoresistive element element 5' C, , B-phase magnetoresistive element element 5°B, ..., D-phase magnetoresistive element 5'
D, , A phase magnetoresistive element element 5°A, 2. C
The lower ends of the phase magnetoresistive element 5'C1□, the B-phase magnetoresistive element 5°B1□, and the D-phase magnetoresistive element 5'D12 are commonly connected by a connecting conductive wire 25.

It is connected to a power terminal V2 formed at the lower end of the insulating substrate 12.

A-phase magnetoresistive element element 5'' A, , C-phase magnetoresistive element element 5' C, 3, B-phase magnetoresistive element element 5' B13.D-phase magnetoresistive element element 5'
DI3. A-phase magnetoresistive element element 5'A, 4. The upper ends of each of the C-phase magnetoresistive element 5"CI4.B-phase magnetoresistive element 5'B, 4.D-phase magnetoresistive element 5'D, 4.

Connecting conductive wire 26, 27. 28, 29, 30° 31.32
．． Connection terminal A5.33 formed at the lower end of the insulating substrate 12. C3, B3. D3A4. c4. B4. Connected to D4.

Also, A-phase magnetoresistive element element 5"A, 5.C-phase magnetoresistive element element 5' C13, B-phase magnetoresistive element element 5'B, 3.D-phase magnetoresistive element element 5'
DI3. A phase magnetoresistive element element 5'A, 4. C-phase magnetoresistive element 5'C14, B-phase magnetoresistive element 5'B, 4. The lower end of each of the D-phase magnetoresistive element elements 5'DI4 is connected to conductive &! Commonly connected by 34.

It is connected to a ground terminal G2 formed at the lower end of the insulating substrate 12.

In this way, each of the second magnetoresistive elements 5°-2 is
Magnetoresistive element element 5'A for A phase to phase of book,
1~''Al1,5'B11~5'B, 4.5C
, □~"14.5'D++~5'DI4, and in order to obtain a two-phase magnetic encoder, the A-phase and B-phase magnetoresistive element elements 5°A1
．． ~5' A14, 5° B ~ 5° Using two sets of B14, these two sets of magnetoresistive elements are superimposed with a phase shift of about λ/8 magnetic pole width so that a four-phase magnetic encoder is obtained. Each of the magnetoresistive element elements 5'A11 to 5'A forming them has the same configuration as that of the
I4+ 5'B1□~5'B10.5' C1□~5
'C, 4, 5' D.

~5'D, 4 does not overlap with other magnetoresistive element elements. This means that the A-phase and B-phase magnetoresistive element elements 5'A+t to 5'A14 and 5°l3tt
In the empty space of ~5'B14, install magnetoresistive element elements 5'01□ for C phase and D phase ~5'CI4 and 5'D.
Since this is the same as rationally incorporating 11 to 5"D14, there is an advantage that the magnetoresistive element 5' of the present invention can be formed with a small width.

Referring to FIG. 4, magnetoresistive element elements 5' for A phase, B phase, C phase, and D phase A1, 5°A1□, 5
'A, and 5'Al1.5' Bll, 5'B1
□, 5'B13 and 5°BI4.5°CI3,5'CI
2.5' CI3 and 5' C+4+ and 5”Dl
l.

5''+2+5' DI3 and 5''DI4 are assembled to form a bridge circuit, and output magnetic encoder output signals to output terminals 35, 3637.
38, 39, 40, 41 and 42.

In the bridge circuit shown in FIG. 4, a magnetic encoder circuit 44 is configured by an n (n is an integer of 2 or more) multiplier circuit 43 including the waveform shaping circuit shown in FIG.
m multiplied by 11 from (m is 8 CJ, an integer of earth. kp
m. ) phase magnetic encoder signal is obtained.

In this example, n-2 is selected as iM, and I
The I multiplier circuit 43 constitutes a double multiplier circuit, and since the magnetoresistive cable 5° has a four-phase n4 structure, a total of eight phases are output from the final output terminal 45.46 of the magnetic encoder circuit 44. Magnetic encoder can give you confidence.

Output terminals 35 and 36.37 and 38.39 and 40,
41 and 42 are connected to amplifiers 47°, 48.4(n, 50), respectively, and the output terminal of the amplifier 3850 is
The output terminals of the comparators 51 and 52 are connected to the logic circuit [
The output terminals of converters 53 and 54 are connected to a 9-logic circuit 56.

When the magnetic encoder 1' rotates, the magnetic encoder magnetic pole 2 formed therein also rotates, so the air gap 4
Eight-phase magnetic encoder signals can be obtained from the magnetoresistive element 5', which rotates relative to the magnetic encoder magnetic pole 2.

More specifically, with reference to FIGS. 4 to 6,
The midpoint signal waveform obtained from the output terminal 35 is shown in FIG.
A magnetic encoder signal waveform 57 having a waveform shown in ) is obtained.

The midpoint signal waveform obtained from the output terminal 36 is approximately ^/2 magnetic pole width (180 in electrical angle) from the magnetic encoder signal waveform 57.
A magnetic encoder signal waveform 58 having a phase shift shown in FIG. 6(b) is obtained.

The midpoint signal waveform obtained from the output terminal 37 is approximately λ/'4 magnetic pole width (90 in electrical angle) from the magnetic encoder signal waveform 57.
A magnetic encoder signal waveform 59 having a phase shift shown in FIG. 6(c) is obtained.

The midpoint signal waveform obtained from the output terminal 38 is approximately λ/'2 magnetic pole width (18 in electrical angle) from the magnetic encoder signal waveform 59.
0 degree)> A magnetic encoder signal waveform 60 having a phase shift shown in FIG. 6(d) is obtained.

The midpoint signal waveform obtained from the output terminal 39 is approximately λ/'8 magnetic pole width (45 in electrical angle) from the magnetic encoder signal waveform 57.
A magnetic encoder signal waveform 61 having a phase shift shown in FIG. 6(e) is obtained (').

The midpoint signal waveform obtained from the output terminal 40 is approximately λ/'2 magnetic pole width (18 in electrical angle) from the magnetic encoder signal waveform 61.
A magnetic encoder signal waveform 62 having a phase shift shown in FIG. 6 (f>) is obtained.

The midpoint signal waveform obtained from the output terminal 41 is approximately 3^/'8 magnetic pole width electrical angle 13 from the magnetic encoder signal waveform 62.
A magnetic encoder signal waveform 63 having a phase shift of 5 degrees) shown in FIG. 6 (g>) is obtained.

The midpoint signal waveform obtained from the output terminal 42 is approximately ^/'2 magnetic pole width (18 in electrical angle) from the magnetic encoder signal waveform 63.
A magnetic encoder signal waveform 64 having a phase shift shown in FIG. 6(h) is obtained.

These magnetic encoder signal waveforms 57, 64 are amplified by an amplifier 47°50, and differentially amplified into magnetic encoder signal waveforms 65, 66, and 6768 as shown in (i) to (+> in the figure). Further, the magnetic encoder signal waveforms 65, . . . , 68, which have been shaped into rectangular waves, are converted into rectangular magnetic encoder signal waveforms 69 shown in FIGS.゜70.71 7
The waveform is shaped into 2. The rectangular magnetic encoder signal waveform 69. ..., 72 is 2 by the logic circuits 55 and 56.
The multiplied rectangular magnetic encoder signal waves 73.74 shown in (q) and (r) in the figure are converted to output terminals 45.4.
6, it is possible to extract a magnetic encoder signal waveform with a 90 degree phase difference that allows discrimination of the cw and ccw directions.

If the rising waveform part or the falling waveform part of the two-phase magnetic encoder signal waveform with a 90 degree phase difference obtained from the output terminals 45 and 46 is detected by a magnetic encoder circuit (not shown) and input into a counter, the magnetic encoder 1 degree is detected. It is possible to obtain 8-phase magnetic encoder signals per rotation of
By simply doubling, it is possible to obtain twice the magnetic encoder signal. Also, if you use a quadruple multiplier circuit.

It is possible to obtain a four-fold encoder signal, that is, a magnetic encoder signal divided into 16 parts. In addition.

It goes without saying that an origin signal of one pulse per -rotation can be obtained by the Z-phase magnetoresistive element elements 5'Z and 5'Z12.

[Other Embodiments] In the above embodiments, an example was shown in which a two-phase magnetic encoder signal with a 90 degree phase difference with increased resolution was obtained. It may also be output as the final magnetic encoder signal.

Further, in the above example, an embodiment was shown in which a magnetic encoder signal of twice the frequency is obtained using a four-phase magnetoresistive element, but there is no need to limit it to this, and depending on the configuration of the n-multiplying circuit used, further Large numbers of high resolution magnetic encoders can be formed very easily.

It goes without saying that the present invention is not limited to rotary magnetic encoders, and may also be applied to linear magnetic encoders.

[Effects of the Invention] The magnetic encoder of the present invention has two surfaces with multi-pole magnetization. Even if the magnetization width of the magnetic encoder magnetic poles is not narrowed and the magnetization is not formed, the magnetic encoder can be used for A phase, B soma, C phase, and D soma from the magnetoresistive element. Since it is possible to obtain a reference magnetic encoder signal with a total of 4 phases, it is possible to obtain a higher pulse magnetic encoder signal, and moreover, by using two magnetoresistive elements that can obtain a 2-phase magnetic encoder signal. The result is the same as if they were arranged twice with the phase shifted by approximately λ/'8 magnetic pole width, but
Since it can be formed without doubling, a four-phase magnetoresistive element with short thickness and width can be formed easily and inexpensively.
Moreover, it is possible to obtain a highly reliable product. Therefore,
This has the advantage that a high-resolution magnetic encoder can be assembled extremely easily and at low cost.

In addition, in order to obtain a higher pulse encoder signal, even if the width of the magnetic poles is narrowed by narrowing the width of the magnetic poles magnetized on one surface, it is possible to obtain a higher pulse magnetic encoder signal extremely easily. Since the width between the magnetoresistive element elements and patterns can be widened,
Highly reliable and consistent quality magnetoresistive elements with high yield.
It can be easily manufactured.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a rotary magnetic encoder using an incremental type magnetoresistive element showing an embodiment of the present invention, and FIG. 2 is an enlarged explanatory view of the magnetoresistive element used in the magnetic encoder. Figure 3 is a developed view of the magnetic encoder magnetic pole and the magnetoresistive element group of the magnetoresistive element.
The figure shows a circuit diagram of a bridge configuration of magnetoresistive element groups, Figure 5 is a diagram of an n-multiplying circuit including a waveform shaping circuit, Figure 6 is a waveform diagram of various parts, and Figure 7 is a diagram of a conventional general rotary magnetic encoder. An explanatory diagram, FIG. 8 is an explanatory diagram of a magnetoresistive element that constitutes a magnetoresistive element to explain the principle of a magnetic encoder, FIG. 9 is an explanatory diagram of a magnetoresistive element, current, and magnetic flux, and FIG. is an explanatory diagram of a magnetoresistive element consisting of four magnetoresistive element elements, FIG. 11 is an explanatory diagram of a magnetic encoder signal processing circuit, and FIG. 12 is an explanatory diagram of a 90
2 is a waveform diagram of two rectangular magnetic encoder signals having different phases. FIG. [Explanation of symbols] 1.1'...Rotary magnetic encoder. 2...Magnetic encoder magnetic pole, 2N...N pole. 2S...S pole, 3...Magnetic rotor. 4...Empty jL5.5'...Magnetoresistive element. 5°A, 5'A11.5'A1215' A13
15'A14... Magnetoresistive element element for A phase. 5' B, 5' BII, 5° B1□2
5"F-3,,,5'F3,4...To B phase magnetoresistive element Niremen 15'C,5'C++,5"CI2
．． 5°C13, 5°C+4... Magnetoresistive element element for C phase. 5' D, 5' Dll, 5'D12.5' DI3
．． 5'[)14 ・I) Phase magnetoresistive element Niremen 1~. 5' Z, 5°Z, , 5' Z, □... Z phase magnetoresistive element element 6 6a 6a', 6b, 6b' -- Conductor (magnetoresistive element), 7 Magnetic field. 7X, 7Y... Magnetic field 8... Magnetic encoder signal processing circuit 91...
9-1-1...Resistor. 10-1 10-2...Comparator]]-111-
2... Magnetic encoder signal 12... Insulating board. 13.14.16... Connection conductive wire 17,..., 34... Connection conductive wire 35,..., 42... Output terminal 43... [1 multiplication circuit, 44... Magnetic encoder circuit, 45゜47,・1 556 OR circuit. 57... Shape, V,, V2 G,, G2... Ato CI,... Connecting terminal. 46...Final output terminal. 50...Amplifier. 54... Comparator.・Logic circuit [exclusive・ 74... Magnetic encoder signal wave... Power supply terminal.・Ground terminal. A4. B,...,B4゜C4,D,...,D4...

Claims (1)

[Scope of Claims] A magnetic encoder comprising a multipolar magnetic pole body provided with a large number of N-pole and S-pole magnetic poles with substantially uniform widths, and a magnetic resistance element disposed opposite to the multipolar magnetic pole body. The following components (1
) to (4). (1) There is a plurality of magnetoresistive element element groups for forming the first phase formed at a pitch of approximately λ/2 magnetic pole width along the moving direction of the multipole magnetic pole body. (2) A group of magnetoresistive element elements forming a second phase formed by shifting the phase by approximately λ/8 pitch along the moving direction of the multipolar magnetic pole body from each of the magnetoresistive element element groups of the first phase. That there is. (3) A plurality of second phases formed from each of the first phase magnetoresistive element groups at a pitch of approximately λ/4 magnetic pole width along the moving direction of the multipolar magnetic pole body. There must be a group of magnetoresistive elements. (4) A plurality of fourth phases formed from each of the third phase magnetoresistive element groups at a pitch of approximately λ/8 magnetic pole width along the moving direction of the multipolar magnetic pole body. There must be a group of magnetoresistive elements.