JPS58139014A - Rotary encoder - Google Patents

Abstract

PURPOSE:To obtain output signals whose output deviation is small, by simultaneously taking out the electric signals having the same phase from a plurality of magnetic patterns by magnetic resistor elements wherein at least two magnetic resistance detecting elements are connected in series. CONSTITUTION:A plurality of the magnetic patterns 4a are radially arranged at an equal interval on a magnetic track 4' at the outer surface of a magnetic disk 4. The three pairs of magnetic resistor elements 10a-10f are connected in series between input and output terminals 10g and 10h by five conductors 10i on the surface opposing the magnetic track 4'. The magnetic resistor element part 10 comprising three magnetic resistance elements 10A-10C is arranged. By connecting a current limiting resistor R and a DC power source E in series, the electric signals having the same phase are obtained from 6 magnetic patterns 4a. Since said electric signals become the averaged output with respect to deviation in the pitches and magnetic fluxes of the six magnetic patterns 4a, the output deviation becomes very small.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a four-tally encoder, and particularly to a magnetic detection structure of a magnetoresistive element for magnetic detection disposed facing a magnetic medium.

FIG. 1 is a cross-sectional configuration diagram of essential parts showing an example of a conventionally proposed rotary encoder. In the same figure, 1
As the rotating means, for example, a rotating body such as a DC-1 motor, 2
3 is a rotating shaft connected to this rotating body 1; 3 is a magnetic disk rotating shaft on which magnetic poles (magnetic patterns) are magnetized and written; sr; is a coupling that connects the rotating body rotating shaft 2 and the magnetic disk rotating shaft 3, @a + 6b
8 is a bearing of the magnetic disk rotating shaft 3; T is a magnetoresistive element disposed opposite to the disc-shaped magnetic disk 4 and has a magnetoresistive effect; 8 is an amplifier for amplifying the electrical signal output from the magnetoresistive element T; This is a hack to shield the magnetic disk 41, magnetoresistive element 1, and amplifier from the outside atmosphere.

FIG. 2 is an enlarged plan view of the main parts for explaining the correspondence relationship in which the magnetic disk 4 and the magnetoresistive element T shown in FIG. 1 are disposed facing each other. In the same figure, there are 5
A large number of magnetic patterns 4a written by magnetizing the -N11 pole are equally distributed radially to form a magnetic track 4'. On the surface □ of the disc-shaped magnetic disk 4 facing the magnetic tracker 4', a set of magnetoresistive elements made of, for example, a thin film pattern made of a permanent mask having a circumferential interval width approximately equal to that of the magnetic pattern 4a is provided. The T's are arranged opposite to each other with a predetermined interval between them. In addition, Ta.

1b is an input/output terminal, la and 7d are a magnetic resistance detection section, and a T@L conductor section.

In the rotary encoder configured in this way,
When the rotating body 1 rotates in the direction of the arrow A, the magnetic disk 4 also rotates in the direction of the arrow in synchronization with this, and since the magnetoresistive element 7 is fixedly arranged, the magnetoresistive effect of the magnetoresistive element T causes , a change in output voltage ΔVp-p between input and output terminals 7a and Tb corresponding to the rotation angle of Fi
is obtained. Ninth, the frequency of the output waveform changes depending on the rotation speed. Therefore, by using these functions, it is possible not only to simply count the number of revolutions but also to output information on the degree of rotational speed.

However, in the rotary encoder having the above configuration, there is a problem that the accuracy of the hunting pattern 41 that is magnetized and written on the magnetic disk 4 has a large influence on the accuracy of the output signal. Nineteen. That is, as shown in FIG. 3 (a) (1 can) and (C), one type of electrical output of the same phase is output from each single bond magnetic pattern 4a, but as shown in FIG. The pitch of the magnetic pattern 4a and the deviation (dispersion) of the magnetic flux are shown in the same figure (b),
As shown in (@), the difference is output as a deviation of the electric signal. For example, a 4m magnetic pattern with deviation in pitch
', as shown in the corresponding figures (b) and (c), had the disadvantage that the wavelength and pulse width of the output signal were changed, making it impossible to obtain highly accurate electrical output. In an encoder in which the rotating body 1 has a rotation speed of 1000 r, p, m, there are 1000 magnetic patterns 4a, but each magnetic pattern 4a must be written and magnetized on the magnetic disk 4 with a certain precision. The problem was that it was technically extremely difficult.

Therefore, the present invention provides a magnetoresistive element that is configured by connecting at least two sets of magnetoresistive sensing elements in one row, so that one electrical output is obtained from a plurality of magnetic patterns, and each magnetic pattern It is an object of the present invention to provide a rotary encoder in which the pitch and magnetic flux deviations are made uniform, and the deviation in output accuracy is reduced for reading.

Embodiments of the present invention will be described in detail below using the drawings.

Figure 1s4 is an enlarged plan configuration diagram of essential parts showing the correspondence relationship between a magnetic disk and a magnetoresistive element for explaining an example of the same tally encoder according to the present invention, and the above-mentioned figure and the same description are the same elements, so I will omit that explanation. In the figure, multiple **Oa air patterns 4a are formed on the outer circumferential surface of the magnetic disk 4, and nine magnetic spots 4' are formed evenly distributed radially.
On the opposing surface, three sets of magnetoresistive elements 1 (A, 10 wins, I
DC% i.e. 4) Magnetic detection elements 1 each accounting for 2 pieces and 6 pieces
0m, 16is, 10・, led, 10@, 10f are input/output terminals 10p.

A magnetoresistive element 10 consisting of three sets of magnetoresistive elements 10m, 10m, and 10c formed on the same plane and connected in series with five conductors [l1101] is connected with a predetermined width dimension between them. They are placed facing each other. In this case, similarly to the above, the magnetoresistive element 1 is formed of a permalay thin film pattern having a direction Mi@ which is substantially the same as that of the magnetic pattern 4&.

According to such a configuration, the magnetoresistive element 10 becomes an equivalent circuit as shown in FIG. 5, and therefore the input/output terminal ta
11. By connecting the Naotsuki power supply E with the current limiting resistor In series connected to the 10h gate, the six magnetic patterns 4a
(See figure j114), electrical signals of the same type and phase are obtained. In this case, the electric signal is obtained by averaging the six magnetic patterns 4a with respect to the deviation of the pitch and magnetic flux of the six eight magnetic patterns 41, and the electric signal is obtained as an electrical output. The deviation of the output becomes extremely small. Moreover, if the number of magnetic patterns 4a is further increased, the output individual difference can be further reduced.

In addition, as another example of a butterfly, in the above embodiment, one set of magnetoresistive element 10 is configured with three terminals, that is, the input/output terminals 10F and 10h, and the three terminals on the positive electrode side of the DC power supply E. As shown in FIGS. 6(a) and 6(b), a magnetoresistive element 11 having the same structure as the magnetoresistive element 10 is arranged with a 1/2 magnetic pole pitch shifted, and two magnetoresistive elements 1 and 1 with three terminals are arranged.
, 11, the electrical output can be doubled. Furthermore, similarly as shown in No. 65A, 3
By arranging the terminal elements so as to shift the pitch of two magnetic poles, a bridge connection structure can be formed, and the electrical output can be quadrupled. Furthermore, by arranging elements with the same bridge connection structure as described above, shifted by 14 magnetic pole pitches, electrical outputs with a phase shift of 900 electrical degrees can be obtained, and the magnetic disk 4 (not shown) (see FIG. 4) can be rotated in the forward and reverse directions. It is possible to have a structure that allows one-turn discrimination.

As explained above, according to the present invention, an output signal with a small deviation in accuracy can be obtained, so that a highly accurate magnetic rotary encoder can be obtained, which is an extremely excellent effect.

[Brief explanation of the drawing]

#11 to 3 are diagrams IR4 diagram for explaining an example of a conventional magnetic rotary machine/coder. 111ゝFIG. 5 is a diagram for explaining one embodiment of the magnetic rotary encoder according to the present invention, and FIGS. 6 and 7 are rounded diagrams for explaining other embodiments of the magnetic rotary encoder according to the present invention. It is. 411...magnetic disk, 4m, 4m'...
e・Magnetic pattern (magnetic pole), 4′...Fist magnetic tock, 10, 10^, 10m, IOC@@Φ・Magnetic resistance element, 10m+ 10b+ lee, 10d, 10*,
10f... Magnetoresistive detection element, 10F, 10h
...Toneri output terminal, 101 ...Conductor part, 11
... Magnetoresistive element. Agent Patent Attorney Susuki 1) Yukiyuki Tori\ノ・τ″1 w41 Figure 11112 Figure 3 WJ

Claims (1)

[Claims] A magnetic rotary encoder comprising at least a magnetic medium on which a large number of magnetic patterns are magnetized and written, and a magnetoresistive element arranged to face the magnetic pattern and read the magnetized pattern, wherein the magnetoresistive element has at least two magnetoresistive elements. A 94-voice encoder comprising a set of magnetoresistive elements connected in series and capable of simultaneously extracting electrical signals of the same phase from a plurality of magnetic patterns.