JPH01318918A - Magnetic encoder - Google Patents

Abstract

PURPOSE:To make a magnetic encoder small in size by providing a magnetoresistance element for detecting the origin in a space which is opposite only to one of magnetoresistance elements for a phase A and a phase B which are superposed in slippage from each other by the phase of a magnetic pole width of lambda/4. CONSTITUTION:A magnetoresistance element 19A for a phase A and a magnetoresistance element 19B for a phase B which constitute a magneto- resistance element 19 are formed respectively of groups of conductors 20 in a plurality which are formed in sequence adjacently over a magnetic pole width of (2n+1)lambda of a multiple magnetized body 2' in the shape of comb teeth and have a magnetoresistance effect. The two elements 19A and 19B are formed on an insulative substrate 26 in slippage from each other in a phase by the width of lambda/4 with respect to the direction of rotation. Moreover, a magnetoresistance element 19Z for an origin signal formed in the shape of comb teeth for arranging a plurality of conductors 20 having a magnetoresistance effect adjacently over a magnetic pole width of lambda/4 is formed on a thin-film insulator 48 being opposite only to either the magnetoresistance element 19A or 19B.

Description

[Detailed Description of the Invention] [Industrial Application Field of the Invention] The present invention relates to a magnetic encoder used in automatic equipment, etc., and particularly to a magnetic encoder that has good accuracy and is suitable for use during battery operation. It can be used in any of the , rotary type, and linear type magnetic encoders.

[Prior art and its problems] When performing positioning in various automatic devices, a means is required to measure the rotation angle (propulsion angle) of a motor, etc. per revolution ff1 (travel amount) and convert it into an electrical signal. . For this purpose, devices called encoders are often used.

For example, regarding rotary encoders, there are two types: an incremental type that measures the number of pulses generated in one revolution, and an absolute type that reads a code recorded on the rotor. Also, there are two types of detection power methods: optical and magnetic. In recent years, incremental magnetic encoders have come into widespread use because they are inexpensive and highly reliable.

Figure 7 shows a conventional general rotary magnetic encoder 1.
This is an explanatory diagram of a magnetic encoder magnetic pole 2 in which the outer periphery is magnetized with 2 N poles and 2 S poles alternately and at fine pitches.
A magnetoresistive (effect) element (referred to as an MR sensor) 5 is disposed to face a magnet rotor 3 with a radial gap 4 in between. The magnet rotor 3 may be an integral type made of magnets, or may be formed by applying a magnetic layer to the outer periphery of a suitable rotor drum.

Each of the north pole 2N and the south pole 2S of the magnetic encoder magnetic pole 2 is magnetized to have a width of λ (equal to the width expressed by 2π in electrical angle).

Assuming that the magnetoresistive element 5 is a ferromagnetic magnetoresistive element, for example, in order to explain the principle of the magnetic encoder 1, we will first explain the magnetoresistive effect formed by the ferromagnetic thin film that constitutes the magnetoresistive element 5. Regarding conductor (referring to a magnetoresistive element which is a magnetoresistive material)) 6, Section 8
This will be explained using figures.

This conductor 6 is made of Ni-C with a thickness of, for example, several thousand amps.
The magnetoresistive element 5 can be formed by forming an o-based 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. 9, if the conductor 6 is arranged so that the direction of the current I flowing therein and the magnetic flux 7 are perpendicular, the magnetic flux 7 will go from the north pole 2N to the south pole 2S.

As shown in FIG. 9, this conductor 6 undergoes a decrease in resistance due to the lateral magnetic flux 7x within the magnetic flux 7. still,
7Y indicates magnetic flux in the 4m direction.

The rate of change in the resistance of the conductor 6 at this time is several percent.

When the width of one magnetic pole of magnetic encoder magnetic pole 2 is λ, λ
When the resistance value of the conductor 6 at the positions of /4 and 3λ/4 is R2, the change value of the resistance is Δr.

Phase θ of magnetic pole (2N or 2S) and conductor 6 (-magnetic pole width 2
The resistance value R(θ) is the phase θ when N and 2S are respectively 2π in electrical angle.

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

The lateral magnetic flux 7X is related to one phase θ and the distance between the conductor 6 and the magnetic encoder pole 2, and the conductor 6 also has 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 N pole 2N and the S pole 2S). Similar to the magnetic field, it has the characteristic that the output signal does not change.

Since it is not possible to obtain the A-phase and B-phase magnetic echo signals with the magnetoresistive element 5 having the single conductor 6 described above, for example, as shown in FIG.
, 6b, 6a', and 6b' are sequentially formed with a shift of λ/4 to obtain A-phase and B-phase magnetic encoder signals.

This magnetoresistive element 5 has two conductors 6a and 6a' for obtaining an A-phase magnetic encoder signal, and a conductor 6b for obtaining a B-phase magnetic encoder signal.

6b'.

The conductors 6a and 6a' are connected to one magnetic pole of the magnetic encoder magnetic pole 2 (N pole 2N or S pole 2S) so that the conductors 6a and 6a' have opposite phases to each other.
When the width of is λ (2π in electrical angle), they are formed to be shifted by λ/2 width.

Similarly, the conductors 6b and 6b' are formed to be shifted by a width of λ/2 so as to have opposite phases to each other.

Further, the conductors 6a and 6b, and the conductors 6a' and 6b' are formed to be shifted by a width of λ/4 from each other.

Therefore, the magnetoresistive elements 5 are sequentially shifted by λ/4 pitch,
Conductors 6a, 6b, 6a' and 6b' are formed.

Conventionally, as a circuit for processing the magnetic encoder signal from the magnetoresistive element 5 formed in this manner, there is one method shown in FIG. 11, for example.

The magnetic encoder signal processing circuit 8 of the magnetoresistive element 5 shown in FIG. 11 configures a bridge using resistors 9-1, . -1.10-
2, FIG. 12(a).

It is possible to obtain two rectangular wave magnetic encoder signals 11-1 and 11-2 having different phases by 90 degrees as shown in FIG.

By counting the rectangular wave magnetic encoder signals 11-1 and 11-2 using a counter, the rotation angle of the magnetic encoder can be measured.

The magnetic encoder signal processing circuit 8 of the magnetoresistive element 5 shown in FIG.
, 6b and 6b' are used as a magnetic encoder signal output.

The magnetoresistive element 5 formed in this way can be drawn as a magnetoresistive element 5' having conductors for the A phase as shown in FIG. I can draw.

A conductor 6a in this magnetoresistive element 5'.

The conditions for forming 6a° are exactly the same as those explained for the magnetoresistive element 5 above, and the tri-toothed conductors 6a and 6a' are
They are formed at positions whose λ magnetic pole width phases are opposite to each other. The other end of the conductor 6a and one end of the conductor 6a' are commonly connected.

The intermediate portion thereof is connected to a conductor 12 for a midpoint output terminal.

One end of the conductor 6a is connected to the positive side of the power battery 14 via the terminal conductor 13, and the other end of the conductor 6a' is connected to the negative side of the power battery 16 via the terminal conductor 15'. ing.

Connection point 1 between the negative side of the power battery 14 and the positive side of the power battery 16
7 and the output terminal conductor 12, the output terminal 18-1.
18-2 is taken out.

According to such a magnetoresistive element 5', these conductors 6a,
6a' is sensitive to the magnetic field parallel to the two surfaces of the magnetic encoder magnetic poles of the magnet rotor 3 to reduce resistance.

This magnetic field component is large at the magnetic pole boundary of the magnetic encoder magnetic pole 2 of the magnet rotor 3, and is O at the center of the magnetic pole, so that the conductors 6a, 6a provided at positions with different magnetic pole widths
' is the number of times the potential at the midpoint crosses O because the polarity changes as the magnet rotor 3 rotates.
1. By taking out from 18-2 and counting,
The rotation speed of the rotor can be measured.

By the way, the magnetoresistive element with the above configuration 5° (of course 2
The conductors 6a, 6a' of the magnetoresistive element 5 are also the same.
According to , the change in the midpoint potential as the magnet rotor 3 rotates results in a narrow output signal waveform 2 as shown in FIG.
It is often 2.22°. This is particularly noticeable when the distance between the magnet rotor 3 and the magnetoresistive element 5' is shorter than the magnetic pole pitch.

Measuring the point where a short waveform with many potential areas near zero crosses zero is likely to contain errors due to fluctuations in the reference voltage, especially when converting to a digital signal, and may lead to malfunctions due to noise. The problem was that it was easy.

Incidentally, in the case of an incremental type magnetic encoder, unlike an absolute type magnetic encoder, the absolute position cannot be determined, but compared to the absolute type, it has the advantage that it can take a relatively large number of pulses while being smaller.

This incremental magnetic encoder has two phases (
origin) Magnet rotor 3 in Figure 15 to obtain the signal
' As shown in the conventional magnetic encoder magnetic pole 2, in addition to the multi-pole magnetized body 2' with a north pole of 2°N and a south pole of 2'S,
In addition to providing a magnetic track 28 for the origin signal on which a magnetized portion 27 for the origin signal (Z phase signal) for one pulse is formed, a multipolar magnetized body 2 is provided as shown in FIG. Magnetoresistive element elements 29A, 29 for obtaining magnetic encoder signals for A phase and B Tagawa opposite to '
In addition to providing the magnetization section 27 for the origin signal (Z phase signal)
It is necessary to dispose a magnetoresistive element 31 facing the magnet rotor 3'', which is provided with an origin detection magnetoresistive element element 30 for obtaining a Z-phase magnetic encoder signal at a position facing the magnetic encoder signal.

The magnetoresistive element 31 having such a structure includes the A-phase magnetoresistive element 29A and the B-phase magnetoresistive element 2 in order to obtain the A-phase and B Tagawa magnetic encoder signals.
9B must be arranged with a phase shift of (mλ+λ/4) magnetic pole width (m is an integer of 1 or more, and λ is the interval of one magnetic pole width of 2 degrees of the multi-pole magnetized body).

This is because the A-phase magnetoresistive element 29A and the B-phase magnetoresistive element 29B must be arranged on the surface of the insulating substrate 32 with a phase shift of (mλ+λ/4) magnetic pole width.

(mλ+λ/4) A space corresponding to the magnetic pole width is wasted in the magnetoresistive element 31.

Furthermore, in order to obtain the A-phase and B Tagawa magnetic encoder signals using the magnetoresistive element 5'', two of these magnetoresistive elements 5'' are used, resulting in wasted space mλ+ as described above.
The magnetic encoder must be arranged at a distance of λ/4 (m is an integer of 1 or more) apart from the magnetic pole width, which has the drawback of making the magnetic encoder large and expensive.

The magnetoresistive element 31 is provided with an origin detection magnet at a position above the A-phase and B-phase magnetoresistive elements 29A and 29B of the insulating substrate 32 and at a position where the origin detection magnetized portion 27 can be detected. A conductive terminal 35 is formed by forming a resistive element element 30 and guiding its conductive terminal 35 to the upper part of the substrate 32 on the opposite side to the conductive terminals 33 and 34 of the A-phase and B-phase magnetoresistive element elements 29A and 29B. Therefore, only the length of the conductor for gluing between the conductive terminal 35 and the conductive terminal 35 is required.

This has the drawback that the length of the magnetoresistive element 31 in the axial direction becomes long, making the magnetoresistive element 31 and the magnetic encoder expensive and large. Further, in the case of a conventional magnetoresistive element or a magnetoresistive element 31 shown in FIG.

One or two magnetoresistive elements having Z phase
Since it is constituted by a conductor having a magnetoresistive effect, the magnetoresistive elements 5' and 31 for the A phase and the B Tagawa magnetoresistive element elements 6a, 6a', 29A,
Similar to No. 29B, only a narrow output signal waveform can be obtained, and an incremental magnetic encoder having a highly accurate origin signal cannot be obtained.

[Means for Solving the Problems] The inventors of the present application have conducted various studies regarding methods for solving the above problems, but the width is approximately uniform.

In a magnetic encoder consisting of a magnet rotor in which a large number of magnetic poles (multi-pole magnetized body, corresponds to the magnetic encoder magnetic pole 2 described above) are provided alternately, and a magnetic resistance element arranged opposite to the magnet rotor, approximately Ni with uniform width,
A magnetic encoder in which a magnetoresistive element is arranged opposite to a magnetized body having a multipolar magnetic pole track provided with a large number of S-pole magnetic poles and a magnetized track for origin detection having a magnetized part for origin detection. A resistive element faces the multi-pole magnetic track, approximately (2n+1)λ (where n is an integer of 0 or more,
λ is the width of one magnetic pole of the above-mentioned multi-pole magnetized body) Consisting of a group of conductors having a magnetoresistive effect for obtaining an output signal of a magnetic encoder for physiognomy, which is formed in a comb-like shape or the like in sequence over the magnetic pole width. An output terminal for obtaining an A-phase magnetic encoder output is provided at the midpoint of a group of conductors having a magnetoresistive effect in the A-phase magnetoresistive element, and an output terminal for obtaining an A-phase magnetic encoder output is provided. The B-phase magnetic encoder output signal is formed in the same manner as the A-phase magnetoresistive element, and is superimposed on the A-phase magnetoresistive element with a λ/4 magnetic pole width phase shifted from the A-phase magnetoresistive element. A B-phase magnetoresistive element composed of a group of conductors having a magnetoresistive effect is provided to obtain a B-phase magnetic encoder output at the midpoint of the B-phase magnetoresistive element's conductor group having a magnetoresistive effect. An output terminal is provided to obtain the above A-phase magnetoresistive element element and B
The objects of the present invention can be achieved by providing a magnetic encoder in which a conductive terminal of the origin detection magnetoresistive element is formed at a position facing only one side of the phase magnetoresistive element.

That is, the magnetoresistive element is approximately (2n+1) of the multipolar magnetic pole body.
λ (where n is an integer greater than or equal to 0, λ is 1 of the magnetic encoder)
Width of magnetic pole) Consisting of a group of conductors having a magnetoresistive effect formed in a comb-like shape or the like in succession across the width of the magnetic pole,
Finding 1: By providing an output terminal at the midpoint of a group of conductors having the magnetoresistive effect and obtaining a magnetic encoder output from the output terminal, a good signal close to a rectangular wave (or trapezoidal wave) can be output. This led to the present invention.

As a magnetoresistive element, a group of conductors having a magnetoresistive effect over the width of the (2n+1) magnetic poles are uniformly arranged adjacent to each other.
If the phase magnetoresistive element element and the B-phase magnetoresistive element element are overlapped, there is almost no increase in the width area of the magnetoresistive element, and there are almost no negative effects such as an increase in cost or an increase in size. do not have.

Moreover, as a magnetoresistive element, one of the A-phase magnetoresistive element element and the B-phase magnetoresistive element element is provided with a group of conductors having a magnetoresistive effect over (2n+1)λ magnetic pole width arranged uniformly adjacent to each other. Since the conductive terminal of the magnetoresistive element element for origin detection is formed in the open position facing only the magnetoresistive element for origin detection, even if the magnetoresistive element element for origin detection (for two phases) is formed, the magnetoresistive element element will Therefore, the magnetic encoder can be formed compactly and inexpensively.

[Function] The magnetoresistive element according to the magnetic encoder of the present invention has its A
The phase magnetoresistive element element and the B-phase magnetoresistive element element are conventional magnetoresistive elements 5'' and 31 conductors having a magnetoresistive effect in large numbers over (2n+1) λ magnetic pole width in the moving direction of the mover. It can be thought that they are formed by overlapping each other in the thickness direction while shifting them little by little along the .

When such superposition is performed, the output waveform approaches a rectangular wave (or trapezoidal wave) as shown in FIGS. 5 and 6. With such a waveform, there are few periods close to zero, so there are few changes in the zero crossing point due to fluctuations in the reference voltage, which is convenient for converting such a waveform into a digitized magnetic encoder signal, and it is also less affected by noise. , a highly accurate and reliable magnetic encoder can be obtained.

A pair of magnetoresistive elements formed in this way (in the examples shown below, this magnetoresistive element part is referred to as a magnetoresistive element element) is prepared for A phase and B horse, and this is further connected to a λ/4 magnetic pole. If the width phase is shifted and the magnetic encoder signals for the A phase and B horse are obtained by doubling them,
Compared to the conventional one that uses two magnetoresistive elements as shown in Figure 13, even though the thickness increases by several to ten microns, the lateral length can be reduced to less than half. Therefore, the magnetic encoder can be made compact.

In addition, the magnetoresistive element for origin detection is also used for A phase and B phase.
Similarly to the phase magnetoresistive element element, a large number of conductor numbers (mλ+λ/4) having the magnetoresistive effect of the origin detection magnetoresistive element of the conventional magnetoresistive elements 5' and 31 are connected to the movable element over the magnetic pole width. By configuring them so that they are overlapped in the thickness direction while being shifted little by little along the moving direction, it is possible to obtain a rectangular wave origin signal output waveform with less change in the zero crossing point due to fluctuations in the reference voltage. Therefore, it is possible to construct an incremental magnetic encoder having a highly accurate and reliable origin signal.

In the magnetoresistive element formed in this way, a conductive terminal of the magnetoresistive element for origin detection is further provided in the vacant part facing only one of the A-phase magnetoresistive element and the B-phase magnetoresistive element. Therefore, even if a magnetoresistive element element for origin detection (Z layer) is formed, the magnetoresistive element will not be large as in the conventional case, and the magnetic encoder can be formed compactly and inexpensively.

[Example] Fig. 1 shows an incremental magnetic encoder 3 of the present invention.
FIG. 2 is an exploded perspective view of the magnetoresistive element 19 used in FIG.

FIG. 3 is a schematic perspective view of an incremental magnetic encoder 36 using the magnetoresistive element 1.
9, the A-phase magnetoresistive element 19A and the B-phase magnetoresistive element 19B are configured so that the A-phase and B-phase magnetic encoder signals can be obtained, and the origin (Z-phase) signal is The configuration of the magnetoresistive element element 19Z for the origin signal is illustrated to enable the origin signal to be obtained.

The magnetic resistance element 19 receives the A-phase magnetic encoder signal ^
/4 magnetic pole width (λ indicates the width of one magnetic pole of the multi-pole magnetized body 2'). In order to obtain a B-phase magnetic encoder signal with a phase shift, first, a plurality of magnetic encoders are formed adjacently in sequence. An A-phase magnetoresistive element element 19A is formed of 20 groups of linear conductors having a comb-like magnetoresistive effect, and from the magnetoresistive element element 19A, a plurality of combs are formed adjacent to each other in sequence. B phase magnetoresistive element element 19B consisting of 20 groups of linear conductors having tooth-like magnetoresistive effect is λ/4 from magnetoresistive element element 19A.
Thin film insulators 4 formed with magnetic pole widths out of phase and each having a width larger than that of the magnetoresistive element elements 19A and 19B.
8. It is formed on the upper surface of the insulating substrate 26 such as a glass substrate by the above-mentioned appropriate means.

Further, the upper surface of the A-phase magnetoresistive element 19A is larger than that of the magnetoresistive element 19A.

A thin film insulator 49 having a large width and approximately the same size as the thin film insulator 48 is provided, and this thin film insulator 48.49 allows the magnetoresistive element element 19A to
, protecting 13B.

The thin film insulators 48 and 49 are output terminal conductors 12A, 12B, and 13A, which will be described later.

In order to expose terminals 13B, 15A, 15B, 41, 42, and 43, terminal exposing notches 48a and 50° 51,49a are formed in the thin film insulator 48,49. These notches 48a, 50, 51, 49a are the terminals 12A, 12B, 13A, 13B, 15A, 15B.
, 41, 42, and 43 need to be formed with an appropriate width at positions that do not overlap with other terminals.

As shown in FIGS. 1 and 2, the A-phase magnetoresistive element 19A constituting the magnetoresistive element 19 has a (2n+1)λ (n is 0 or more) of the multipolar magnetized body 2' (see FIG. 3). , where λ is the width of one magnetic pole of magnetic encoder magnetic pole 2) Magnetic pole width 1 For example, if n=0 as in this embodiment, the magnetic encoder magnetic poles 2 are successively adjacent over one magnetic pole width λ. When viewed from the rotation direction of the magnetic encoder magnetic pole 2, which divides the 20 groups of conductors formed over the range of λ magnetic pole width into two, the 20 groups of conductors are formed in a comb-like shape and have a magnetoresistive effect. The midpoint output terminal conductor 12A is taken out from the conductor portion 20' located at the center. In the drawing divided into two by the output terminal conductor 12A, the left half, that is, the group of 20 conductors formed over a range of λ/2 width is defined as a magnetoresistive element 2LA,
Conductor 2 formed over the right half, that is, the range of λ/2 width
The 0th group will be expressed as magnetoresistive element 21A'.

These magnetoresistive elements 21A, 21A' are formed by appropriate means on the thin film insulator 48 as described above, thereby forming the magnetoresistive element element 19A for obtaining the A-phase magnetic encoder output signal. .

Moreover, the magnetoresistive element 19B constituting the magnetoresistive element 19 is (2n
+l) λ (n is an integer greater than or equal to 0. λ is the width of one magnetic pole of the magnetic encoder magnetic pole 2) Magnetic pole width 8 For example, if n = 0, the width of one magnetic pole λ of the multi-pole magnetized body 2' is A multi-pole magnetized body 2° which divides into two the 20 groups of conductors formed over the range of the width of two magnetic poles, which are formed by a plurality of 20 groups of comb-shaped conductors having a magnetoresistive effect and are adjacent to each other. The midpoint output terminal conductor 12B is taken out from a position of the conductor portion 20' located at the center as viewed from the rotational direction.

In the drawing divided into two by the output terminal conductor 12B, the left half, that is, the group of 20 conductors formed over a range of λ/2 width is defined as the magnetoresistive element 21B, and the right half, that is, λ/2 A group of 20 conductors formed over a width range will be referred to as a magnetoresistive element 21B''.

The magnetoresistive elements 21B, 218' are formed on the insulating substrate 26 by appropriate means as described above, thereby forming the magnetoresistive element 19B for obtaining the B-phase magnetic encoder output signal.

This magnetoresistive element 19B is arranged so that a B-phase magnetic encoder signal whose phase is shifted from the magnetoresistive element 19A by a width of λ/4 in two rotational directions is obtained. They are formed on the insulating substrate 26 with a phase shift of 4 widths.

The 20 groups of conductors formed on the thin film insulator 48 are covered with a thin film insulator 49 so as to protect them.

By doing this, the conductors 20 groups are mutually arranged by λ/4 over one magnetic pole width λ of the magnetic encoder magnetic pole 2.
They were formed with a phase shift of the width of the magnetic pole. A magnetoresistive element element 19A consisting of A-phase and B Tagawa magnetoresistive elements 21A and 21A', and a magnetoresistive element 21
Magnetoresistive element 19B consisting of B and 21B'
forming each.

In other words, it is not necessary to form the A-phase magnetoresistive element element and the B Tagawa magnetoresistive element element with different magnetic pole widths so that they do not overlap each other (mλ+λ/4<m is an integer greater than or equal to 1) as in the conventional method. Therefore, there is an advantage that the magnetoresistive element 19 can be formed into a small and narrow element.

Moreover, by configuring as described above, the magnetoresistive elements 21A and 21A'' and the magnetoresistive elements 21B and 21B' are the same as those formed in opposite phases to each other.

The magnetoresistive element 19A is connected to the conductor 20 at the other end of the magnetoresistive element 2LA and the magnetoresistive element 21A°.
A common connection is made to the conductor 20 at one end, and the connected intermediate portion is drawn out and connected to the midpoint output terminal conductor 12A. The conductor 20 at one end of the magnetoresistive element 21A is connected to the positive side of the power supply battery 14A via the terminal conductor 13A.

The conductor 20 at the other end of the magnetoresistive element 21A' is connected to the negative side of the power supply battery 16A via the terminal conductor 15A. Output terminals 18A-1 and 18A-2 are connected to take out the A-phase magnetic encoder output from the connection point 17A between the negative side of the power supply battery 14A and the positive side of the power supply battery 16A, and the conductor 12A for the midpoint output terminal. I'm taking it out.

Further, the magnetoresistive element 19B is connected to the conductor 20 at the other end of the magnetoresistive element 21B and the magnetoresistive element 21
The conductor 20 at one end of B° is commonly connected, and the connected intermediate portion is drawn out and connected to the midpoint output terminal conductor 12B. The conductor 20 at one end of the magnetic resistance element 21B is connected to the positive side of the power supply battery 14B via the terminal conductor 13B, and the conductor 20 at the other end of the magnetic resistance element 21B is connected to the positive side of the power supply battery 14B via the terminal conductor 13B.
0 is connected to the negative side of the power source 16B via the terminal conductor 15B. Output terminals 18B-1 and 18B-2 are connected to take out the B-phase magnetic encoder output from the connection point 17B between the negative side of the power supply battery 14B and the positive side of the power supply battery 16B, and the conductor 12B for the midpoint output terminal. I'm taking it out.

According to such a magnetoresistive element 19, the group of conductors 20 having a magnetoresistive effect reduces resistance by sensing a magnetic field parallel to the multipolar magnetized body 2' of the magnet rotor 3' shown in FIG. 3, for example.

This magnetic field component is generated by the multi-pole magnetized body 2 of the magnet rotor at 3°.
The magnetoresistive element elements 19A and 19B formed over the range of (2n+l)λ are large at the magnetic pole boundary of 3°, and 0 at the center of the magnetic pole.
Since the polarity changes with the rotation of the output terminals 18A-1, 18A-2, 18B
The number of revolutions of the rotor can be measured by extracting and counting the magnetic encoder outputs from -1 and 18B-2.

By the way, according to the magnetoresistive element 19 having the above configuration, the change in the midpoint potential due to the rotation of the magnet rotor 3'' is caused by the change in the midpoint potential of the magnetoresistive element 21A of the magnetoresistive element 19A.
and 21A', and the magnetoresistive elements 21B and 21B' of the magnetoresistive element 19B are each formed by a plurality of conductor groups 20 over a λ/2 magnetic pole width, so that the magnetoresistive elements 21A and 21A', 21
By B and 21B°, waveforms similar to those shown in Fig. 14 are obtained, as shown in Figs. 4(a) and (b), respectively, with waveforms 22A and 22A', and waveforms 22B and 22B' of λ/2 magnetic pole width. Two output signal waveforms 22A and 22A'', 22B and 22B consisting of a narrow signal group with a λ/4 magnetic pole width phase shifted as if superimposed while being shifted little by little over a range.
It can be considered that ° can be obtained.

Therefore, these waveforms 22A and 22A', 22B and 22
B' is actually an integrated waveform, so it is synthesized as shown by dotted lines 23A and 23A' and 23B and 23B' in the same figure, and as a result, the potential at the midpoint is Trapezoidal wave (or rectangular wave) as shown in Figures 5 and 6
Output signal waveforms 24A and 24A', 24B and 24B°
They can be taken out from the output terminals 18A-1 and 18A-2, 18B-1 and 18B-2.

Such output signal waveforms 24A and 24A''.

According to 24B and 24B°, unlike the output signal waveform 22 and 22' shown in Fig. 13, there are fewer parts close to zero, so there are fewer points that cross the zero potential.1The measurement of this zero point is based on the standard. Since errors due to voltage fluctuations are no longer included and noise is also reduced, noise malfunctions are eliminated.

In the A-phase and B-Tagawa magnetoresistive elements 19, waveforms 24A, 24A', 24B, and 24B' shown in FIGS. 5 and 6 can be obtained.

By forming the magnetoresistive element elements 19A and 19B with the λ/4 magnetic pole width phase shifted as described above, the first
If the magnetic encoder signal processing circuit 8 shown in FIG. 1 is used,
It is possible to obtain two rectangular wave encoder signals 11-1 and 11-2 having phases different by 90 degrees as shown in FIGS. 11(a> and 11(b)).

Therefore, these square wave encoder signals 11-1.1
By counting 1-2 with a counter, the rotation angle of the magnetic encoder, etc. can be measured.

In the magnetoresistive element 19 configured as described above, 1
Magnetoresistive element elements 19A and 19B for human phase and B phase
This forms a wasted space 37 that does not overlap with each other.

Therefore, the magnetoresistive element for the origin signal is placed in a position where it can face the magnetized portion 27 for the origin signal of the magnetic track 28 for the origin signal on the thin film insulator 48 on the upper part of the magnetoresistive element 19A (in the drawing of FIG. 1). form 19z,
Terminal lead wires 38, 39, 40 of this origin signal magnetoresistive element 19Z are formed on the thin film insulator 48 through the space 37.

In the present invention, the origin signal magnetoresistive element 19Z may be constructed of one or two conductors 20 having a magnetoresistive effect, as in the conventional case.

However, in this embodiment, for the same purpose as the A-phase and B-phase magnetoresistive element elements 19A and 19B, the portion near zero of the origin output signal waveform is reduced, and the error due to fluctuations in the reference voltage is small. In order to obtain an accurate origin output signal waveform without noise malfunction, (2n
+1) It is desirable to form a plurality of conductors 20 having a magnetoresistive effect adjacently arranged over the λ magnetic pole width or mλ+λ/4 magnetic pole width.

Therefore, in this embodiment, a plurality of magnetoresistive elements are provided over the λ/4 magnetic pole width on the thin film insulator 48 that is in the same phase as the space 37 and faces only one of the magnetoresistive element elements 19A and 19B. In order to arrange the effective conductors 20 adjacently, a comb-shaped origin signal magnetoresistive element element 19z is formed.

The conductor 20 at one end of the origin signal magnetoresistive element 19Z is connected to the terminal conductor 41 formed at the lower end of the thin film insulator 48 (in the paper plane of FIG. 1) via the terminal lead wire 38. There is.

The conductor 20 at the other end of the origin signal magnetoresistive element 19Z is connected to a terminal conductor 43 formed at the lower end of the thin film insulator 48 (in the plane of the paper in FIG. 1) via a terminal lead wire 40. ing.

Conductor 20 of magnetoresistive element element 19Z for origin signal
The midpoint is connected via a terminal lead wire 39 to a midpoint output terminal conductor 42 formed at the lower end of the thin film insulator 48 (in the paper plane of FIG. 1).

The conductor 41 is connected to the positive side of the power battery 44 , and the conductor 43 is connected to the negative side of the power battery 45 . The output terminal 46 taken out from the conductor 42 and the power batteries 44 and 4
The origin signal output waveform is obtained from the output terminal 47 taken out from the connection point with 5, and the origin magnetic encoder output is taken out.

Based on this origin signal output waveform, cw with reference to the origin,
Encoder pulses in the ccw direction can be counted.

[Effects of the Invention] The magnetic encoder of the present invention can extract magnetic encoder signals for A phase, B phase, and origin from the magnetoresistive element with a rectangular wave or trapezoidal wave output potential. Alternatively, the error when digitizing the trapezoidal wave output is very small, and a high-precision magnetic encoder can be constructed inexpensively and easily, making it possible to accurately and stably measure position with a simple W configuration. It becomes possible.

Furthermore, since the magnetoresistive element according to the present invention has a long conductor, a magnetoresistive element with high electrical resistance can be easily obtained, and a magnetic encoder with low power consumption can be constructed. This makes the magneto-resistance element ideal for use as a magnetic encoder, especially during battery operation.

Moreover, the effect resulting from the greatest feature of the present invention lies in the magnetoresistive element for use in the above-mentioned magnetic encoder. Since they are shifted and overlapped,
There is an effect that the magnetic encoder can be formed small and inexpensively without making the magnetoresistive element large and expensive.

In particular, a pair of magnetoresistive element elements for A phase and B phase are prepared, and these are further overlapped with a phase shift of λ/4 magnetic pole width to generate magnetic encoder signals for A phase and B phase. Even if the thickness increases by several to tens of microns compared to the conventional one using two magnetoresistive elements as shown in FIG. Since it can be made compact to one-fold or less, the magnetic encoder can be made compact.

Moreover, the magnetoresistive element for use in the magnetic encoder of the present invention is obtained by overlapping the A-phase and B-phase magnetoresistive elements with the λ/4 magnetic pole width phase shifted as described above.
When the A-phase magnetoresistive element element and the B-phase magnetoresistive element element are offset and face each other, a vacant part is formed that does not face each other, so that the conductive part of the origin detection magnetoresistive element is formed in this vacant part. Because the terminal is formed, even if a magnetoresistive element element for origin detection (Z Tagawa) is not formed, the magnetoresistive element does not become large as in conventional methods, and the magnetic encoder can obtain the origin output signal. Moreover, it can be formed at low cost.

Another method is to arrange a plurality of such magnetoresistive elements at the same phase position (it goes without saying that the plurality of magnetoresistive elements may be configured into one magnetoresistive element). ), it is also possible to obtain a more accurate and reliable magnetic ender signal.

In the above description, a rotary magnetic encoder has been described, but it goes without saying that the present invention can also be applied to a linear magnetic encoder.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a magnetoresistive element used in an incremental magnetic encoder capable of waiting for an origin signal, showing an embodiment of the present invention, and FIG. 2 is an exploded perspective view of the magnetoresistive element shown in FIG. Figure 3 is a schematic perspective view of the same magnetic encoder;
The figure is an explanatory diagram for detailed explanation of the present invention when the magnetoresistive elements shown in Figures 1 to 3 are used, and Figure 5 is the output of the magnetic encoder for phase A of the magnetoresistive element used in the present invention. FIG. 6 is a waveform diagram showing the output signals of the A-phase and B Tagawa magnetic encoders of the magnetoresistive element used in the present invention, and FIG. 7 is a schematic diagram of a conventionally known incremental type rotary magnetic encoder. 8 to 10 are explanatory diagrams of the relationship between the magnetic encoder magnetic poles of the magnetic encoder and the magnetoresistive element. FIG. 11 is an explanatory diagram of the magnetic encoder processing circuit of the magnetoresistive element. An encoder signal waveform diagram obtained from the encoder, Fig. 13 is an explanatory diagram of the conventional A-phase magnetoresistive element ♀, and Fig. 14 shows the output signal of the magnetic encoder when the magnetoresistive element of Fig. 13 is used. 15 is a schematic perspective view of a conventional magnetic encoder capable of obtaining an origin signal, and FIG. 16 is a perspective view of a magnetoresistive element used in the magnetic encoder of FIG. 15. [Explanation of symbols] 1... Rotary magnetic encoder. 2...Magnetic encoder magnetic pole, 2"...Multi-pole magnetized body, 2N, 2N'...N pole. 23.2S"...S pole, 3.3'...Magnet rotor, 4... ... air gap, 5.5' ... magnetoresistive element. 6.6a, 6a', 6b, 6b' --- Conductor (magnetoresistive element), 7.7X, 7Y... Magnetic flux, 8.
...Magnetic encoder signal processing circuit. 9-1. ..., 9-4...Resistor. 10-1.10-2...Comparator. 11-1.11-2...Magnetic encoder signal. 12.12A, 12B... Conductor for midpoint output terminal, 1
3.13A, t3M... Terminal conductor 114.14A
, 14B...Power battery. 15.15A, 15B... Conductor for terminals. 16.16A, 16B...Power battery. 17.17A, 17B... Connection point 1 18-1.18-2, 18A-1, 18A-2゜18B
-1, 18B-2... Output terminal. 19... Magnetoresistive element. 19A... Magnetoresistive element for human faces. 19B...B Tagawa's magnetoresistive element. 19Z... Magnetoresistive element element for origin signal, 20
...Conductor, 20゛ ...Conductor part. 2LA, 21A'...Magnetic resistance element for A phase, 21B, 21B'...B Tagawa's magnetic resistance element. 22.22', 22A, 22A'...Output signal waveform. 23A, 23A', 23B, 23B'... dotted line, 2
4A, 24A', 24B, 24B'...Output signal waveform, 25...Thin film insulator. 25a... Notch for terminal exposure, 26... Insulating substrate,
27... Magnetized part for origin detection, 28... Magnetic track for origin signal, 29A... Magnetoresistive element element for A phase, 29B... Magnetoresistive element element for A phase, 30
... Magnetoresistive element element for origin detection, 31...
Magnetoresistive element. 32... Insulating substrate, 33, 34. 35... Conductive terminal, 36... Incremental magnetic encoder, 37
···space. 38.39.40...Terminal lead wire. 41... Conductive terminal, 42... Midpoint output conductor, 4
3... Conductive terminal, 44.45... Power supply battery, 46.
47...Output terminal. 48.49... Thin film insulator. 48a, 49a, 50.51... Notches for exposing terminals.

Claims (2)

[Claims] (1) A magnetoresistive element is attached to a magnetized body having a multipolar magnetic pole track in which a large number of magnetic poles of N and S poles are provided with approximately uniform width, and a magnetized track for origin detection that has a magnetized part for origin detection. A magnetic encoder in which a magnetoresistive element faces the multipolar magnetic track and has a magnetic field of approximately (2n+1)λ.
(However, n is an integer greater than or equal to 0, and λ is the width of one magnetic pole of the above-mentioned multi-pole magnetized body.) To obtain the A-phase magnetic encoder output signal formed in a comb-like shape or the like sequentially and continuously over the magnetic pole width. An A-phase magnetoresistive element element configured by a conductor group having a magnetoresistive effect is provided, and an A-phase magnetic encoder output is obtained at the midpoint of the A-phase magnetoresistive element group of conductors having a magnetoresistive effect. An output terminal is provided for the purpose, and is formed in the same manner as the A-phase magnetoresistive element element, and
By a group of conductors having a magnetoresistive effect to obtain a B-phase magnetic encoder output signal superimposed on the A-phase magnetoresistive element with a λ/4 magnetic pole width phase shifted from the A-phase magnetoresistive element. A B-phase magnetoresistive element configured as above is provided, an output terminal for obtaining a B-phase magnetic encoder output is provided at the midpoint of the conductor group having a magnetoresistive effect of the B-phase magnetoresistive element, and the above-mentioned A A magnetic encoder in which a conductive terminal of a magnetoresistive element for origin detection is formed at a position facing only one of a phase magnetoresistive element and a B-phase magnetoresistive element. (2) The magnetoresistive element element for origin detection is (m
λ+λ/4) Claim No.
) magnetic encoder.