JPH0452650Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a magnetic rotary encoder, and in particular to a holding device for holding a magnetic sensor for detecting magnetic signals in a position facing a magnetization pattern provided on a rotating body. Regarding parts.

[Prior Art] FIG. 9 shows a schematic configuration of a conventionally known magnetic rotary encoder. In the same figure, 1
2 is a drum, 2 is a rotating shaft, 3 is a magnetization pattern, 4 is a magnetic sensor, 5 is a holding member, and 6 is a base.

A drum 1 made of a magnetic material is rotatable about a rotating shaft 2 by a motor (not shown) or the like, and has a magnetization pattern 3 magnetized on its circumferential surface by magnetic recording technology. This magnetization pattern 3 is continuously formed at equal pitches such as N, S, S, N, N, S, S, N, etc. so that adjacent magnetic pole pairs have opposite polarities. The magnetic sensor 4 is a known type made of, for example, a magnetoresistive element, and is fixed to the sensor mounting surface 5a of the holding member 5 by adhesive or the like. The holding member 5 is made of a metal material such as aluminum or a synthetic resin material, and its lower surface is the mounting reference surface 5.
a and screw 7 onto the reference plane part 6a of the base 6.
It is attached by.

The magnetoresistive elements constituting the magnetic sensor 4 are arranged in two sets so that the phase is shifted by np+1/4p (n is an integer) with respect to each magnetic pole pitch p of the magnetization pattern 3 magnetized and arranged on the drum 1. and
Further, these magnetoresistive elements are arranged opposite to the magnetization pattern 3 such that their respective magnetic path directions are orthogonal to the rotating shaft 2. Therefore, when the drum 1 rotates, each magnetoresistive element of the magnetic sensor 4 outputs a signal having a phase difference of 90 degrees.

In the magnetic rotary encoder configured as described above, when the drum 1 rotates in a predetermined direction, a continuous signal with a phase difference of 90 degrees is output from each magnetoresistive element of the magnetic sensor 4. By performing processing such as amplification, detection, and matching on these pulses, incremental pulses are obtained, and the displacement amount and rotation direction of the drum 1 are detected.

[Problem that the invention attempts to solve]

By the way, in such a magnetic rotary encoder, it is necessary to keep the distance between the circumferential surface of the drum 1 on which the magnetization pattern 3 is formed and the magnetic sensor 4 constant and parallel. Parallelism (tilt angle) with sensor 4 is 10th
As shown in the figure, the angle θ ₁ is tilted, or the 11th
As shown in the figure, when the center line of the magnetization pattern 3 and the azimuth angle of the magnetic sensor 4 are inclined by an angle θ ₂ , the output of the magnetic sensor 4 decreases, making accurate position detection impossible. For this reason, the perpendicularity of the sensor mounting surface 5a of the holding member 5 with respect to the reference plane portion 6a and the flatness of the mounting reference surface 5b must be maintained with high precision.

Conventionally, the sensor mounting surface 5a and mounting reference surface 5b of the holding member 5 are cut out by cutting a metal material such as aluminum, or after obtaining an approximate external shape by die casting or injection molding, cutting is performed. A method has been adopted in which secondary processing such as machining is performed to finish the sensor mounting surface 5a and the mounting reference surface 5b.

However, with these conventional methods, the finished state of the sensor mounting surface 5a and the mounting reference surface 5b is not stable. For example, if the mounting reference surface 5b is finished with unevenness, when the screw 7 is tightened, the retaining member 5 and the mounting reference surface 5b are not stable. There is a problem that the magnetic sensor 4 fixed to the magnetic sensor 4 is tilted, and there is also a problem that the finishing process requires a lot of time and the cost increases.

Furthermore, even if the sensor mounting surface 5a and the mounting reference surface 5b are plate-finished with high precision, since the holding member 5 is fixed on the base 6 using the screws 7,
There was another problem in that the magnetic sensor 4, which had been adjusted to the correct position, would fluctuate due to the rotational torque when the screw 7 was tightened.

Therefore, the purpose of the present invention is to solve the above-mentioned problems of the conventional technology, to make it possible to form a holding member by press working without impairing the finishing accuracy of the sensor mounting surface or the mounting reference surface, and to achieve detection accuracy at low cost. To provide high quality magnetic rotary encoders.

[Means for solving problems]

In order to achieve the above object, the present invention includes a rotating body having a magnetization pattern arranged in a circumferential direction, and a holder mounted on a reference flat part of a base disposed outside the rotating body. and a magnetic sensor fixed to the holding member and facing the magnetization pattern, and detecting a change in the position of the magnetization pattern due to the rotational movement of the rotating body based on a change in the output of an electric signal from the magnetic sensor. In the magnetic rotary encoder, a pair of legs are arranged opposite to each other at a predetermined distance from the holding member made of a metal plate, and have a broken surface as a mounting reference plane, and a pair of legs are bridged between these leg pieces, A sensor mounting surface is provided that is continuous at a bent portion perpendicular to a plane including the mounting reference surface, and the holding member is configured such that the mounting reference surface is connected to the reference plane portion by a free end of a leaf spring provided on the base. It is characterized in that it is pressed and fixed to the leaf spring via an adhesive.

[Effect]

When the holding member is configured as described above, the mounting reference surface becomes a plane connecting a plurality of fractured surfaces punched out from a metal plate at predetermined intervals, so that high flatness is achieved. In addition, since the sensor mounting surface is bent along a straight line perpendicular to the straight line connecting the fractured surfaces, as long as this perpendicularity is maintained, even if the bending angle changes due to springback, it will maintain a high squareness. is realized. Furthermore, since such a holding member is temporarily fixed using the elastic force of a leaf spring attached to the base and then fixed to the leaf spring using adhesive, the position adjustment work of the magnetic sensor is unnecessary. This can be done easily and reliably, and the holding member can be installed in a narrow space.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

Fig. 1 is a cross-sectional view showing a magnetic rotary encoder according to an embodiment of the present invention, Fig. 2 is a partially sectional plan view showing the main parts of the magnetic rotary encoder, and Fig. 3 is the magnetic rotary encoder. FIG. 4 is a perspective view of a holding member provided in the magnetic rotary encoder, and FIG. 5 is an exploded view thereof.

As shown in FIGS. 1 to 3, a pair of grooves 8a are formed in the base 8 made of a metal material, and the periphery of these grooves 8a forms a flat reference plane portion 8b. A rotating shaft 10 is supported at the center of the base 8 via a bearing 9, and a drum 11 whose circumferential surface is magnetized with a magnetization pattern (not shown) is fixed to the upper end of the rotating shaft 10. ing. Further, a horseshoe-shaped leaf spring 12 is attached to the upper surface of the base 8 with a screw 13, and a free end 12a of the leaf spring 12 extends to a position facing the groove 8a.

The magnetic sensor 14 is a known sensor made of, for example, a magnetoresistive element, and is bonded to a holding member 15, which will be described later, and faces the magnetization pattern of the drum 11 at a predetermined distance. This holding member 15 is
The lower surface serves as a mounting reference surface that comes into contact with the reference plane portion 8b of the base 8, and is fixed to the free end 12a of the leaf spring 12 with an adhesive 16. Note that 17 is a printed circuit board on which circuit elements (not shown) are mounted, and 18 is a cover attached to the base 8.

As shown in FIG. 4, the holding member 15 is made of a pressed metal plate, and includes a sensor mounting surface 15a for adhering the magnetic sensor 14, and a pair of leg pieces 15c having ears 15b at the lower ends. These sensor mounting surfaces 15a and both leg pieces 1
The lower surface of 5c serves as a mounting reference surface 15d. The leg piece 15c is formed to be bent approximately 90 degrees rearward from both sides of the sensor mounting surface 15a,
The lower surface of the sensor mounting surface 15a and the lower surface of both leg pieces 15c (excluding the portion where the ear pieces 15b are formed) are formed flush with each other. Also, the ear piece 15b is the leg piece 15.
After extending downward from the bottom of c, it is bent outward at an angle of approximately 90 degrees.

In order to form the holding member 15 constructed in this way, first, the flat metal plate 19 is punched out to obtain a shape as shown in FIG. Here, since the outer shape of the pressed metal flat plate 19 is determined by the cutting die (die and punch) of the press machine,
A highly accurate fracture surface is obtained, and a part of this fracture surface (indicated by reference numeral 19a in the figure) is the above-mentioned mounting reference surface 15.
d. Next, a straight line A connecting this fracture surface 19a
- Two straight lines B-B' and C- perpendicular to A'
When the flat metal plate 19 is bent approximately 90 degrees at the C' position, the portion 19b surrounded by these straight lines B-B' and C-C' (the hatched portion in the figure) becomes the sensor mounting surface 15a, and Part 19 on both sides
c becomes the leg piece 15c. Therefore, the fracture surface 19
The plane including a (the plane perpendicular to the plane of the paper in the figure) and the hatched portion 19b are at right angles, and the sensor mounting surface 1
5a is perpendicular to the mounting reference surface 15d. The bending angle at this time corresponds to θ ₃ in FIG. 4, but even if the bending angle θ ₃ varies due to springback, the sensor mounting surface 15
The perpendicularity of a is not affected in any way.

Also, before and after the above-mentioned bending process, A-
When the flat metal plate 19 shown in FIG. 5 is bent approximately 90 degrees at the D-D' position parallel to the line A', this bending line D-D' is located at a portion away from the fracture surface 19a, so the mounting standard is A bent portion 19d that becomes the ear piece 15b is formed on both leg pieces 15c without deforming the surface 15d.

After obtaining the holding member 15 having the shape shown in FIG. 4 from the metal flat plate in this manner, the magnetic sensor 14 is positioned and adhesively fixed to the sensor mounting surface 15a of the holding member 15. On the other hand, there is a screw 1 on the base 8.
3 to secure the leaf spring 12, and this leaf spring 12
The lug 15b of the holding member 15 to which the magnetic sensor 14 is glued is inserted into the space defined by the free end 12a of the drum and the groove 8a of the base 8, and the magnetic sensor 14 and the drum are connected using a microscope, an output meter, etc. 11 (the surface on which the magnetization pattern is formed) is adjusted to a predetermined state. In this case, the holding member 15 has both ear pieces 15b.
is elastically biased toward the bottom side of the concave groove 8a of the base 8 by the free end 12a of the leaf spring 12, so the simple operation of moving the mounting reference surface 15d along the reference plane portion 8b of the base 8 As a result, the magnetic sensor 14 can be adjusted parallel to the circumferential surface of the drum 11 without any azimuth deviation, and the adjusted holding member 15 is held (temporarily fixed) on the base 8 by the leaf spring 12.

After adjusting the magnetic sensor 14 to a predetermined position in this way, the contact portion between the leaf spring 12 and the holding member 15,
That is, adhesive 1 is applied to the free end 12a and the ear piece 15b.
The holding member 15 is mounted on the base 8 by filling the holding member 6 and solidifying it.

FIG. 6 is a perspective view of a magnetic rotary encoder according to another embodiment of the present invention, in which parts corresponding to those in the first embodiment described above are given the same reference numerals.

In this embodiment, the leg piece 15c of the holding member 15
A window hole 15e is formed from the sensor mounting surface 15a to the sensor mounting surface 15a, and the free end 12 of the leaf spring 12 is inserted into the window hole 15e.
a, and apply adhesive 16 to this elastic contact part.
The holding member 15 is mounted on the base 8 by filling it with . Therefore, the lug 15b required in the first embodiment described above can be omitted, and the installation space can be reduced. Note that the holding member 15
The rest of the parts are basically the same as those in the first embodiment, and a detailed explanation will be omitted, but each mounting reference surface 15d in this embodiment also utilizes the fractured surface when a flat metal plate is pressed, Since the sensor mounting surface 15a and both leg pieces 15c are bent along a straight line perpendicular to the plane including the fractured surface, the flatness of the plane including each mounting reference surface 15d and the sensor mounting surface 15
The squareness of a is maintained with high accuracy.

In each of the above embodiments, a magnetic rotary encoder in which a magnetization pattern is magnetized on the outer peripheral surface of the drum 11 has been described, but as shown in FIG.
Needless to say, the present invention can also be applied to a magnetic rotary encoder in which a magnetization pattern is provided on the inner circumferential surface of the drum 11 having an inverted concave cross-sectional shape, and the magnetic sensor 14 is arranged to face the magnetization pattern.

Further, the magnetic recording medium having a magnetization pattern is not limited to the drum described above, but the present invention can also be applied to a magnetic recording medium in which a magnetization pattern is formed on the flat disk surface 20a of the disk 20, as shown in FIG. 8ab. In this case, the mounting reference surface 15d of the holding member 15 may be pressed against the reference plane portion 8b of the base 8, which is parallel to the rotation axis 10, by using the elastic force of the leaf spring 12.

Furthermore, in each of the above embodiments, the sensor mounting surface 15a of the holding member 15 and the lower surface of both leg pieces 15c are used as the mounting reference surface 15d, but this mounting reference surface 15d is formed at least on the lower surface of both leg pieces 15c. For example, the lower surface of the sensor mounting surface 15a may be broken at a position away from the reference plane portion 8d of the base 8 with respect to the lower surface of both leg pieces 15c.

[Effect of idea]

As explained above, according to the present invention, not only can the desired parallelism and flatness required for the holding member be obtained by the fractured surface when pressing a flat metal plate, but also the flatness of the leaf spring can be obtained. Since the holding member is temporarily fixed and permanently fixed using the magnetic sensor, adjustment work for the magnetization pattern of the magnetic sensor becomes easy and reliable, and the holding member can be installed in a narrow space, making it inexpensive. A magnetic rotary encoder with high detection accuracy can be provided.

[Brief explanation of the drawing]

Figures 1 to 5 are for explaining a magnetic rotary encoder according to an embodiment of the present invention. Figure 1 is a vertical cross-sectional view of the magnetic rotary encoder, and Figure 2 shows its main parts. A partially sectional plan view, FIG. 3 is a perspective view thereof, and FIG. 4 is a perspective view of the holding member.
FIG. 5 is a developed view thereof, FIG. 6 is a perspective view of a magnetic rotary encoder according to another embodiment of the present invention, and FIG. 7 is a longitudinal section of a magnetic rotary encoder according to yet another embodiment of the present invention. 8a is a side view of a magnetic rotary encoder according to another embodiment of the present invention, FIG. 8b is a perspective view thereof, and FIG. 9 is a perspective view of a conventional magnetic rotary encoder, FIGS. 10 and 11 are explanatory diagrams showing problems in the conventional example. 11...drum, 12...leaf spring, 12a...
Free end, 14... Magnetic sensor, 15... Holding member, 15a... Sensor mounting surface, 15b... Ear piece,
15c...Leg piece, 15d...Mounting reference surface, 15e
... window hole, 16 ... adhesive, 19 ... metal plate,
20...disk, 20a...disk surface.

Claims (1)

[Scope of utility model registration request] a rotating body having a magnetization pattern arranged in a circumferential direction; a holding member attached to a reference plane part of a base disposed outside the rotating body; A magnetic rotary encoder is provided with a magnetic sensor facing the pattern, and detects a change in the position of the magnetization pattern due to the rotational movement of the rotating body based on a change in the output of an electric signal from the magnetic sensor. A pair of leg pieces facing the holding member at a predetermined interval and having the fractured surface as the mounting reference plane, and a bent part bridging between these leg pieces and perpendicular to the plane containing the mounting reference plane. The holding member is provided with a continuous sensor mounting surface, and the mounting reference surface of the holding member is pressed against the reference flat part by the free end of the leaf spring provided on the base, and an adhesive is applied to the leaf spring. A magnetic rotary encoder characterized in that it is fixed to the magnetic rotary encoder.