JPH01318916A - Magnetic encoder - Google Patents

Abstract

PURPOSE:To make a magnetic encoder small in size by forming a conducting terminal of a magnetoresistance element for detecting the origin in a spacing part of a magnetic pole width of (mlambda+lambda/4) between a magnetoresistance element for a phase A and a magnetoresistance element for a phase B. CONSTITUTION:A magnetoresistance element 19A of a phase A constituted of a group of straight conductors 20 in a plurality which are formed in sequence adjacently in the shape of comb teeth and have a magnetoresistance effect, and a magnetoresistance element 19B of a phase B constituted likewise of a group of straight conductors 20 in a plurality which are formed in sequence adjacently in the shape of comb teeth and have the magnetoresistance effect, are formed on the upper surface of an insulative substrate 26 formed to be larger in width than the magnetoresistance elements 19A and 19B, so that the element 19B is slid from the element 19A by the phase of a magnetic pole width of (mlambda+lambda/4). Besides, a magnetoresistance element 19Z for an origin signal is formed at a position whereat it can be opposite to a magnetized part for the origin signal of a magnetic track for the origin signal, and lead wires 38, 39 and 40 for terminals are formed on the insulative substrate 26.

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 relates to a magnetic encoder that has good accuracy and is suitable for use during bath battery operation. Regarding the encoder, it can be used for either rotary type or 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)9 of the motor, etc.9 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 during two rotations, and an absolute type that reads a code recorded on the rotor. Furthermore, there are two types of detection methods: optical and magnetic. Recently, incremental magnetic encoders, which are inexpensive and have excellent reliability, have come into widespread use.

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 units.
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 through it and the magnetic flux 7 are perpendicular to each other, the magnetic flux 7 will go from the north pole 2N to the south pole 2S.

As shown in FIG. 9, this conductor 6 causes a decrease in resistance value due to the lateral magnetic flux 7X within the magnetic flux 7. still,
7Y indicates longitudinal magnetic flux.

At this time, the rate of change in the resistance of the conductor 6 is a few percent.

When the width of one magnetic pole of magnetic encoder magnetic pole 2 is λ, λ
Let Δr be the resistance value of the conductor 6 at the positions of /4 and 3λ/4 and the change value of the R9 resistance.

The phase θ of the magnetic 4i (2N or 2S) and the conductor 6 (-phase θ when the magnetic pole widths 2N and 2S are respectively 2π in electrical angle)
The resistance value R(θ) at ) is .

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

The lateral magnetic flux 7X is related to the three phases θ and the distance between the conductor 6 and the magnetic encoder pole 2, and the conductor 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 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 A-phase and B-phase magnetic echoder 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 (N pole 2N or S pole 28) of the magnetic encoder magnetic pole 2 so that they have opposite phases to each other.
When the width of is 2π in electrical angle, they are formed with a width shifted by λ/2.

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 from each other by a width of λ/4.

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'' as shown in (b).

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.

If the magnetoresistive element 5 formed in this way is drawn by taking out only the A-phase conductors 6a and 6a', the magnetoresistive element 5 with the A-phase conductors as shown in FIG. You can also 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 comb-like conductors 6a and 6a' are arranged so that the λ magnetic pole width phases are separated from each other and the phases are opposite to each other. It is formed. The other end of the conductor 6a and one end of the conductor 6a' are commonly connected.

The middle thereof is connected to the conductor 12 for the 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 the conductors 6a, 6a provided at positions with different λ 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 5' having the above structure, of course,
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.
2.22' in many cases, and this is particularly noticeable when the distance between the magnet rotor 3 and the magnetoresistive element 5' is short compared to 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 it has the advantage that it can take a relatively large number of pulses while being smaller than a two-absolute type.

In this incremental type magnetic encoder, the Z phase (
origin) Magnet rotor 3 in Fig. 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 N pole 2'N and S pole 2°S, there is also a magnet for the origin signal (Z phase signal) for one pulse. In addition to providing a magnetic track 28 for the origin signal on which a magnetic portion 27 is formed, as well as magnetic tracks 28 for the A phase and B layers facing the multipolar magnetized body 2' as shown in FIG. Magnetoresistive element elements 29A, 2 for obtaining encoder signals
9B, and the magnetized part 2 for 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 opposite to the magnetoresistive element 7.

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

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.

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, the length of the lead conductor between the conductive terminal 35 and the conductive terminal 35 is the same.

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 element elements 6a, 6a', 29A of the A-phase and B layers of the magnetoresistive elements 5', 31,
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 invention have conducted various studies on methods for solving the above problems, and have found a method in which a large number of N-pole and S-pole magnetic poles are provided with approximately uniform widths. A magnetic encoder in which a magnetoresistive element is arranged opposite to a magnetized body having a polar magnetic pole track and a magnetized track for origin detection having a magnetized part for detecting an origin, wherein the magnetic resistance element is opposed to the multi-pole magnetic pole track. , approximately (2n+1)λ (where 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) For A phase formed in a comb-like shape or the like continuously over the magnetic pole width. An A-phase magnetoresistive element composed of a group of conductors having a magnetoresistive effect for obtaining a magnetic encoder output signal is provided, and an A An output terminal is provided to obtain the phase magnetic encoder output,
It is formed in the same way as the A-phase magnetoresistive element element, and is formed from the A-phase magnetoresistive element (mλ+λ/
4) Magnetic pole width (m is an integer greater than or equal to 1, and is an integer given independently of the above n) Consisted of a group of conductors having a magnetoresistive effect to shift the phase and obtain the B-phase magnetic encoder output signal. A magnetoresistive element element for B phase 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 A-phase magnetoresistive element and the B-phase magnetoresistive element The object of the present invention can be achieved by forming the conductive terminal of the magnetoresistive element for origin detection in the (mλ+λ/4) magnetic pole width vacant part of the element.

That is, in the magnetoresistive element, each of the A-phase and B-layer magnetoresistive element elements is approximately (2n+1)λ of the multipolar magnetic pole body of the multipolar magnetic track (where n is an integer of 0 or more,
λ is the width of one magnetic pole of the magnetic encoder) It is composed of a group of conductors having a magnetoresistive effect that are successively formed in a comb-like shape or the like over the magnetic pole width, and a conductor group having a magnetoresistive effect is set at the midpoint of the group of conductors having a magnetoresistive effect. The present invention was based on the discovery that by providing an output terminal and obtaining a magnetic encoder output from the output terminal, a good signal close to a rectangular wave (formed as a trapezoidal wave) can be output.

As a magnetoresistive element, a conductor group having a magnetoresistive effect over (2n+1)λ magnetic pole width is arranged uniformly adjacent to A.
The conventionally wasted part between the phase magnetoresistive element and the B-phase magnetoresistive element, that is, the part (mλ+λ/4) between the A-phase magnetoresistive element and the B-phase magnetoresistive element ) Since the conductive terminal of the magnetoresistive element element for origin detection is formed in the open part of the magnetic pole width, even if the magnetoresistive element element for origin detection (Z layer) is formed, the magnetoresistive The element does not become large, and the magnetic encoder can be formed in a small size and at low cost.

[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 at 5 degrees, and a large number of conductors having a magnetoresistive effect of 31 are arranged 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 being shifted little by little along the thickness direction.

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 is little change in the zero-crossing point due to fluctuations in the reference voltage, which is convenient for converting such a waveform into a digital magnetic encoder signal, and there is little influence from noise, making it possible to obtain a highly accurate and reliable magnetic encoder.

In addition, the magnetoresistive element for origin detection is also used for A phase and B phase.
Similarly to the phase magnetoresistive element, a large number of conductors having a magnetoresistive effect of the origin detection magnetoresistive element of the conventional magnetoresistive elements 5' and 31 are placed over the magnetic pole width (mλ+λ/4) of the movable element. By configuring them so that they are overlapped in the thickness direction while being shifted little by little along the movement 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. An incremental magnetic encoder having a highly accurate and reliable origin signal can be constructed.

In the magnetoresistive element formed in this way, the space that was wasted in the conventional method, that is, the (mλ+λ/4) magnetic pole width of the A-phase magnetoresistive element and the B-phase magnetoresistive element Since the conductive terminal of the magnetoresistive element element for origin detection is formed in the
Even if a magnetoresistive element element for origin detection (for two phases) is formed, the magnetoresistive element does not become large as in the conventional case, and the magnetic encoder can also be formed in a small size and at low cost.

[Example 1] 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 magnetoresistive element 19 receives (
mλ+λ/4) magnetic pole width (m is an integer greater than or equal to 1, and is an integer given independently of the integer n described later, λ is the multipolar magnetized body 2
2) For example, in this embodiment, 9m21 is selected, so λ + λ/4 magnetic pole width is phase shifted so that a B-phase magnetic encoder signal can be obtained. In order to do this, first, an A-phase magnetoresistive element element 19A consisting of a plurality of 20 groups of linear conductors having a comb-like magnetoresistive effect formed adjacent to each other is formed, and from the magnetoresistive element element 19A, Similarly, the B-phase magnetoresistive element 19B, which is composed of a plurality of 20 groups of linear conductors having a comb-like magnetoresistive effect and formed adjacent to each other, is connected to the magnetoresistive element 19A by λ+λ.
/4 magnetic pole width The magnetic poles are formed by suitable means as described above on the upper surface of the insulating substrate 26, such as a glass substrate, which is formed to have a width larger than that of the magnetoresistive element elements 19A and 19B, respectively, with a phase shift, and to be described later on the upper surface thereof. A thin film insulator 25 having a notch 25a for exposing a terminal is formed.

The thin film insulator 25 includes output terminal conductors 12A, 12B, 13A, 13B, 15A, 15B, 4, which will be described later.
1, 42, and 43, a notch 25a for terminal exposure is formed in the thin film insulator 25. This notch 25a is provided with the terminals 12A, 12B, 1
3A.

It is necessary to form terminals 13B, 15A, 15B, 41, 42, and 43 with appropriate widths 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). , λ is the width of one magnetic pole of a multi-pole magnetized body 2 degrees) Magnetic pole width 9 For example, taking the case where n=o as in this example,
The conductor is formed by a plurality of 20 groups of conductors formed in a comb-like shape having a magnetoresistive effect and adjacent to each other in sequence over one magnetic pole width λ of the multi-pole magnetized body 2', and the conductor is formed over the range of λ magnetic pole width. 20
The conductor 12A for the mid-point output terminal is taken out from the conductor portion 20' located at the center of the multi-pole magnetized body 2'' which divides the group into two in the direction of rotation. In the diagram divided into two by the conductor 12A, the left half, that is, the group of 20 conductors formed over a range of λ/2 width is defined as the magnetoresistive element 21A, and the right half, that is, the λ/2 width.
A group of 20 conductors formed over a width range will be referred to as a magnetoresistive element 21A'.

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

Moreover, the magnetoresistive element 19B constituting the magnetoresistive element 19 is (2) of the multipolar magnetized body 2' (see FIG. 3).
n+1) λ (n is an integer greater than or equal to 0. λ is the width of one magnetic pole of magnetic encoder magnetic pole 2) magnetic pole width.

For example, taking the case where n=0, the magnetic encoder magnetic pole 2 is formed of a plurality of comb-shaped conductors 20 that are successively adjacent to each other over one magnetic pole width λ and have a magnetoresistive effect, and λ The midpoint output terminal conductor 1 is inserted from the conductor portion 20' position located at the center of the multi-pole magnetized body 2' which divides the 20 groups of conductors formed over the magnetic pole width range into two.
I'm trying to take out 2B. In the drawing divided into two by the output terminal conductor 12B, the left half, λ
A group of 20 conductors formed over a range of /2 width is referred to as a magnetoresistive element 21B, and a group of 20 conductors formed over a range of λ/2 width in the right half is referred to as a magnetoresistive element 21B.
It will be expressed as B''.

These 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 has a width of λ/4 (
However, in order to obtain a B-phase magnetic encoder signal whose phase is shifted by a width of λ+λ/4 (when m=1) with respect to the rotation direction, is formed.

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

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 21A 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 2LA 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
A common connection is made to the conductor 20 at one end of B', 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 magnetoresistive 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 magnetoresistive element 218
is connected to the negative side of the power supply battery 16B via the terminal conductor 15B. Negative side of power battery 14B and power battery 16
Connection point 17B with the positive side of B and conductor 12 for the midpoint output terminal
Output terminals 18B-1 and 18B-2 for taking out the B-phase magnetic encoder output are taken out from B.

According to such a magnetoresistive element 19, these A-phase and B-phase magnetoresistive element elements 19A.

The 20 groups of conductors having a magnetoresistive effect of 19B are 1, for example, the magnetic multipole magnetized body 2 of the magnet rotor 3' shown in FIG.
′ reduces the resistance by sensing the parallel magnetic field.

This magnetic field component is generated by the multi-pole magnetized body 2 of the magnet rotor 3'.
The polarity of the magnetoresistive elements 19A and 19B, which are formed over a range of <2n+l)λ, changes as the magnet rotor 3 rotates. In order to
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 accompanying 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 groups of 20 conductors over a λ/2 magnetic pole width, so that the magnetoresistive elements 21A and 21A', 21B
and 21B'', the waveform similar to that shown in FIG. 14 becomes waveform 2 as shown in FIGS. 4(a) and (b), respectively.
2A and 22A', waveforms 22B and 22B' are two output signals consisting of a narrow signal group with a λ/4 magnetic pole width phase shifted as if they were superimposed while being shifted slightly over the λ/2 magnetic pole width range. Waveforms 22A and 22A', 22B and 22
It can be considered that "B" 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', 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 22.22' shown in Fig. 14, there are fewer parts close to zero, so there are fewer points crossing the zero potential, and the 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.

Waveforms 24A, 24A', 24 shown in FIGS. 5 and 6
In the A-phase and B-phase magnetoresistive elements 19 that can obtain B and 24B', the magnetoresistive element elements 19A and 19B are formed with the λ/4 magnetic pole width phase shifted as described above. By using the magnetic encoder signal processing circuit 8 shown in FIG. 11, it is possible to obtain two rectangular wave encoder signals 11-1 and 11-2 having 90° different phases as shown in FIGS. 11(a) and 11(b). I can do it.

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,
Magnetoresistive element elements 19A and 19B for A phase and B phase
There is 1mλ+λ/4 magnetic pole width 2m=0, then λ/4
A wasted space is created by the distance between the magnetic pole widths.

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 insulating substrate 26 above the magnetoresistive element elements 19A, 19B (in the drawing of FIG. 1). An element 19z is formed, and terminal lead wires 38, 39, 40 of this origin signal magnetoresistive element 19Z are formed on the insulating substrate 26 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 origin output signal waveform has fewer parts close to zero, and there is less error due to fluctuations in the reference voltage. In addition, in order to avoid noise malfunction and obtain an accurate origin output signal waveform, (2
It is desirable to form a plurality of conductors 20 having a magnetoresistive effect adjacently arranged over a magnetic pole width of n+1)λ or mλ+λ/4 magnetic pole width.

Therefore, in this embodiment, if mλ+λ/4 magnetic pole width 9m=0 at the upper part of the intermediate part of the magnetoresistive element elements 19A and 19B at the same phase position as the space 37, a plurality of magnetic fields are formed over the λ/4 magnetic pole width. In order to arrange the conductor 20 having a resistance effect 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 a terminal conductor 41 formed at the lower end of the insulating substrate 26 (in the paper of FIG. 1) via a terminal lead wire 38. .

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 insulating substrate 26 (in the paper of FIG. 1) via a terminal lead wire 40. There is.

The center point of the conductor 20 of the origin signal magnetoresistive element 192 is connected to the insulating substrate 26 via the terminal lead wire 39.
It is connected to a midpoint output terminal conductor 42 formed at the lower end (in the plane of the paper 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 source 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 the magnetic encoder signals for the A phase, the B layer, and the 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 highly accurate magnetic encoder can be constructed inexpensively and easily, making it possible to accurately and stably measure position with a simple configuration. become.

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.

Furthermore, the effect resulting from the greatest feature of the present invention lies in the magnetoresistive element for use in the above-mentioned magnetic encoder. A conductive terminal of the magnetoresistive element for origin detection was formed in the part where the magnetoresistive element for origin detection was located, that is, in the part where the magnetic pole width was (mλ+^/4) between the A-phase magnetoresistive element element and the B-phase magnetoresistive element element. Therefore, even if a magnetoresistive element element for origin detection (Z layer) is formed, the magnetoresistive element does not become large as in the past, and a magnetic encoder that can obtain an origin output signal can also be formed in a small size and at low cost. can do.

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 obtaining an origin signal showing an embodiment of the present invention, FIG. 2 is an exploded perspective view of the magnetoresistive element of FIG. 1, and FIG. The figure is a schematic perspective view of the magnetic encoder.
The figure is an explanatory diagram for detailed explanation of the present invention when the magnetoresistive elements shown in Figs. 1 to 3 are used, and Fig. 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 magnetic encoder of the A-phase and B-layers of the magnetoresistive element used in the present invention, and FIG. 8 to 10 are schematic explanatory diagrams of the relationship between the magnetic encoder magnetic poles and the magnetoresistive element, FIG. 11 is an explanatory diagram of the magnetic encoder processing circuit of the magnetoresistive element, and FIG. An encoder signal waveform diagram obtained from the same magnetic encoder, Figure 13 is an explanatory diagram of the conventional A-phase magnetoresistive element, and Figure 14 shows the output signal of the magnetic encoder when the magnetoresistive element of Figure 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. 2S, 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, 13B... Conductor for terminals. 14.14A, 14B...Power battery. 15.15A, 15B... Conductor for terminals. 16.16A, 16B...Power battery. 17.17A, 17B... Connection points. 18-1.18-2.18A-1,18A-2゜18B
-1, 18B-2... Output terminal. 19... Magnetoresistive element. 19A... Magnetoresistive element for A phase. 19B...B layer magnetoresistive element element. 19Z... Magnetoresistive element element for origin signal, 20
...Conductor, 20'...Conductor part. 21A, 21A'... Magnetoresistive element for A phase, 21B, 21B'... Magnetoresistive element for B layer, 22.22', 22A, 22A'. 22B, 22B'...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 226... Insulating substrate,
27... Magnetized part for origin signal, 28... Magnetic track for origin signal, 29A... Magnetoresistive element element for A phase, 29B... Magnetoresistive element element for B 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 1 38.39.40 ... Lead wire for terminal. 41... Conductive terminal, 42... Midpoint output conductor, 4
3... Conductive terminal. 44.45...Power battery, 46.47...Output terminal.

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, which is formed in the same manner as the A-phase magnetoresistive element, and has a magnetic pole width (mλ+λ/4) from the A-phase magnetoresistive element.
is an integer greater than or equal to 1, and is an integer given independently of the above n)) A B-phase magnetoresistive element composed of a group of conductors having a magnetoresistive effect to shift the phase and obtain a B-phase magnetic encoder output signal. An output terminal for obtaining the 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 A-phase magnetoresistive element and the B-phase magnetoresistive element are connected to each other. A magnetic encoder in which a conductive terminal of a magnetoresistive element for origin detection is formed in a vacant part of the magnetoresistive element for origin detection (mλ+λ/4) magnetic pole width. (2) The magnetoresistive element element for origin detection is (m
λ+λ/4) Claim No.
) magnetic encoder.