JPH0416894Y2 - - 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] An example of a conventionally known magnetic rotary encoder is shown in FIGS. 6 and 7. In these figures, 1 is a disk, 2 is a rotating shaft, 3 is a magnetization pattern, 4 is a magnetic sensor, 5 is a holding member, 6
is a case, 7 is a screw, and 14 is a bearing.

A disk 1 made of a magnetic material is rotatable around a rotating shaft 2 supported by a case 6 via a bearing 14, and a magnetization pattern 3 is attached to the flat disk surface 1a by magnetic recording technology. It is magnetized. As shown in FIG. 7, this magnetization pattern 3 is continuously formed at equal pitches such as N, S, S, N, N, S, S, N... so that adjacent magnetic pole pairs have opposite polarities. ing. 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 is mounted on the flat surface 6a of the case 6 with screws 7, with its lower surface serving as a mounting reference surface 5b. This plane part 6a
When machining the hole 6b in the center of the case 6, the hole 6b is machined so as to be parallel to the circumferential surface of the hole 6b, so that highly accurate parallelism between the two can be maintained relatively easily. Therefore, the parallelism between the rotating shaft 2 supported by the bearing 14 inserted into the hole 6b and the flat portion 6a, in other words, the perpendicularity between the flat portion 6a and the disk surface of the disk 1 is highly accurate. ing.

The magnetoresistive element constituting the magnetic sensor 4 has a magnetization pattern 3 arranged in a magnetized manner on the disk 1.
For each magnetic pole pitch p, np + 1/4p (however, n
is an integer) Two sets of magnetoresistive elements are arranged so as to be out of phase with each other, and are arranged opposite to the magnetization pattern 3 so that the magnetic path direction of each of these magnetoresistive elements is orthogonal to the rotation axis 2. Therefore, when the disk 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 disk 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 disk 1 are detected.

[Problem that the invention attempts to solve]

By the way, in such a magnetic rotary encoder, the disk 1 on which the magnetization pattern 3 is formed is
The distance between the disk surface 1a and the magnetic sensor 4 must be kept constant and parallel, for example, if the parallelism (tilt angle) between the disk surface 1a and the magnetic sensor 4 is at an angle as shown in If the magnetic sensor 4 is tilted by θ ₁ , or if the center line of the magnetization pattern 3 and the azimuth angle of the magnetic sensor 4 are tilted by an angle θ ₂ as shown in FIG. 9, the output of the magnetic sensor 4 will decrease, making accurate position detection impossible. Become. For these reasons, the perpendicularity of the sensor mounting surface 5a of the holding member 5 to the flat 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.

Among these problems, focusing on shortening the processing time, it is possible to form the holding member 5 by performing press processing such as punching or bending on a metal flat plate. Since springback occurs during machining, it has been difficult to achieve the same level of finishing accuracy as the above-mentioned cutting process.

Furthermore, since the substrate of the magnetic sensor 4 is usually made of glass or ceramic, if the holding member 5 is made of a metal material as described above, the magnetic sensor 4 will easily peel off from the holding member 5 due to the difference in coefficient of thermal expansion between the two. There was a problem.

In addition, as described in Japanese Utility Model Application Publication No. 60-72517, a method of correcting the angle θ ₂ shown in FIG. 9 using an azimuth adjustment mechanism after attaching the holding member 5 to the flat part 6a is also proposed. However, this method requires a great deal of time and effort for adjustment, making it unsuitable for mass production.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a magnetic rotary encoder which is inexpensive and has high detection accuracy, which solves the problems of the prior art described above, which enables the formation of a holding member by press working.

[Means for solving problems]

In order to achieve the above object, the present invention includes a rotatable rotating body having a magnetization pattern arranged in a circumferential direction, and a holding member mounted on a predetermined reference plane outside the rotating body. , a magnetic sensor that is fixed to the holding member and faces the magnetization 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. In the rotary encoder, the holding member made of a metal plate has a pair of legs facing each other at a predetermined distance and having fractured surfaces parallel to each other at both ends, and a pair of legs extending between these legs and having one fractured surface. A fixing piece bent in a step-like manner with respect to a plane including the cross section, and a mounting leg formed near the other fracture surface of the metering leg piece and bent at a position away from the fracture surface, The magnetic sensor is bonded to the fixing piece while in contact with the fracture surface on one side, and the holding member is
A feature thereof is that the mounting leg portion is screwed with the other side of the broken surface in contact with the reference plane portion.

[Function] When the holding member is configured as described above, the mounting reference surface for supporting the holding member on the predetermined reference flat portion and the sensor reference surface for positioning the magnetic sensor are both attached to the predetermined flat metal plate. Since it is defined by a plane connecting a plurality of press-cut fractured surfaces at intervals, their parallelism and mutual flatness are highly accurate. In addition, the mounting legs for screwing the holding member to the reference flat surface are bent into leg pieces at positions away from the reference mounting surface, so even if the amount of screw tightening changes, the mounting The flatness of the reference plane and the sensor reference plane and the parallelism between the two are not impaired. Furthermore, the magnetic sensor is not directly fixed to the sensor reference surface, but is bonded onto a fixed piece formed in a step-like manner with respect to the sensor reference surface while in contact with the sensor reference surface. Even if relative movement occurs between the holding member and the magnetic sensor due to a temperature change, there is less risk that the magnetic sensor will peel off from the holding member.

〔Example〕

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

FIG. 1 is a sectional view showing a schematic configuration of a magnetic rotary encoder according to an embodiment of the present invention, FIG. 2 is a perspective view of a holding member and a magnetic sensor provided in the magnetic rotary encoder, and FIG. 3 is a perspective view of the magnetic rotary encoder. A partially cutaway side view showing the attachment state of the holding member;
FIG. 4 is a developed view of the holding member, with reference numeral 8.
shows the holding member comprehensively, and members corresponding to those in FIGS. 6 to 9 are given the same reference numerals.

As shown in FIGS. 1 to 3, the holding member 8
is made of a pressed metal flat plate, and has a substantially rectangular connecting portion 8a and a fixing piece 8b having a through hole 9.
, a pair of leg pieces 8c each having a sensor reference surface 10 at the upper end and a mounting reference surface 11 at the lower end, and a pair of mounting leg portions 8d having mounting holes 12.

The leg pieces 8c are bent rearward at approximately 90 degrees from both sides of the connecting portion 8a, and the mounting leg portions 8d are bent at an angle of approximately 90 degrees outward from the bottom of both leg pieces 8c. The lower surface is located above the mounting reference surface 11. Further, the fixing piece 8b is formed to be bent approximately 90 degrees rearward from the upper edge of the connecting portion 8a, and its upper surface is located below the sensor reference plane 10.

In order to form the holding member 8 constructed in this way, first, a flat metal plate is pressed out to obtain a shape as shown in FIG. Here, the two fractured surfaces A-A and B-B in the figure that are pressed are set to be parallel to each other, but these are determined by the cutting die (soybean and punch) of the press machine. Therefore, a highly accurate fracture surface can be obtained, and the fracture surface along the A-A line is on the sensor reference plane 10 mentioned above, and the fracture surface along the A-A line is aligned with the B-B
The fractured surface along the line becomes the mounting reference surface 11 described above. Next, when the metal flat plate is bent approximately 90 degrees at the positions of two straight lines C-C and D-D perpendicular to these fracture surfaces A-A and B-B, the central square portion surrounded by these straight lines will be The connecting portion 8a becomes the connecting portion 8a, and the rectangular portions on both sides become the leg pieces 8c.

Also, before and after the above-mentioned bending process, A-A
And when the flat metal plate shown in Fig. 4 is bent approximately 90 degrees at positions E-E and F-F parallel to B-B,
The fixed piece 8b is formed by the former bending line E-E.
The latter bending line F--F forms the mounting leg portion 8d. Note that each of the above-mentioned bending angles varies somewhat due to spring back, but due to these variations, the sensor reference plane 10 and the mounting reference plane 1
Parallelism etc. of 1 are not affected.

When the holding member 8 having the shape shown in FIG. 2 is obtained from the flat metal plate in this way, the adhesive 13 is inserted through the through hole 9 of the fixing piece 8b while the lower surface of the magnetic sensor 4 is pressed against both sensor reference surfaces 10. and adhere the magnetic sensor 4 to the fixing piece 8b (see FIG. 3).
After that, as shown in FIG.
The holding member 8 is attached onto the reference plane portion 6c of the case 6 by inserting the screw 7 into the attachment hole 12 and tightening the screw 7. It is assumed that this reference plane portion 6c is processed so as to maintain a high degree of parallelism to the disk surface 1a of the disk 1 in relation to the hole portion 6b. In this case, as shown in FIG. 3, the mounting leg 8d is located at a position apart from the mounting reference surface 11 by a minute amount Δl (this corresponds to the distance between B-B and F-F shown in FIG. 4). for screw 7
Even if there is some variation in the amount of tightening, the holding member 8 will not tilt when attached to the reference plane portion 6c. Therefore, the parallelism between the sensor reference surface 10 and the mounting reference surface 11, which were finished with high precision during press working, or the flatness of each is maintained even when the holding member 8 is attached to the case 6, and the magnetic sensor 4 is It is arranged parallel to the disk surface 1a of the disk 1 without any azimuth deviation. Furthermore, even if the magnetic sensor 4 and the holding member, which have different coefficients of thermal expansion, move relative to each other due to a change in the ambient temperature, the magnetic sensor 4 will be partially stuck to the fixed piece 8 at the center of the lower surface.
b, this movement is absorbed by both sensor reference surfaces 10 sliding on the lower surface of the magnetic sensor 4, and the risk of the magnetic sensor 4 peeling off from the holding member 8 is reduced.

Note that the shape or formation position of the fixing piece 8b and the mounting leg 8d can be changed as appropriate; for example, the fifth
As shown in Figure a, for the purpose of improving the mounting space, the mounting leg 8d is bent inside the leg piece 8c, and as shown in Figure 5b, the fixing piece 8b is bent over the upper edge of the leg piece 8c. You may do so. In these cases as well, the sensor reference surface 10 and the mounting reference surface 11 are formed by the fractured surfaces during press punching, and
By setting the bending positions of the fixing piece 8b and the mounting leg portion 8d at a location away from the fracture surface, the same effects as in the first embodiment can be achieved.

Further, in the first embodiment, the case where the disk 1 is used as the magnetic recording medium having the magnetization pattern 3 has been described, but the present invention can also be applied to a magnetic recording medium in which the magnetization pattern is formed around a drum-shaped rotating body. applicable, and in this case, the holding member 8 is placed on a reference plane parallel to the rotation axis of the magnetic recording medium.
All you have to do is install the .

[Effects of the invention] As explained above, according to the invention, it is possible not only to obtain the desired parallelism and flatness required for the holding member by the fractured surface during press punching, but also to obtain the desired parallelism and flatness required for the holding member. The magnetic sensor can be firmly fixed to the holding member regardless of changes, and it is possible to provide a magnetic rotary encoder that is inexpensive and has high detection accuracy.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a magnetic rotary encoder according to an embodiment of the present invention, FIG. 2 is a perspective view of a holding member and a magnetic sensor provided in the magnetic rotary encoder, and FIG. 3 is a perspective view of the holding member. A partially broken side view, FIG. 4 is a developed view of the holding member,
5a and 5b are perspective views of a holding member according to another embodiment of the present invention, FIG. 6 is a sectional view showing a conventional example of a magnetic rotary encoder to which the present invention is applied, and FIG. 7 1 is a bottom view showing the relationship between a disk and a holding member provided in the magnetic rotary encoder, and FIGS. 8 and 9 are a side view and a front view for explaining the problems of the conventional example. 1... Disk (rotating body), 1a... Disk surface, 2... Rotating shaft, 3... Magnetization pattern, 4...
Magnetic sensor, 6... Case, 6c... Reference plane part, 7... Screw, 8... Holding member, 8a... Connecting part, 8b... Fixing piece, 8c... Leg piece, 8d... Mounting leg part. , 9...Through hole, 10...Sensor reference surface (fractured surface), 11...Mounting reference surface (fractured surface), 12...
Mounting hole, 13...adhesive, 14...bearing.

Claims (1)

[Scope of utility model registration request] a rotatable rotating body having a magnetization pattern arranged in a circumferential direction; a holding member mounted on a predetermined reference plane portion on the outside of the rotating body; A magnetic rotary encoder is provided with a magnetic sensor facing the rotor, and detects a change in the position of a 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, wherein the holding member is made of a metal plate. A pair of legs that face each other at a predetermined distance from each other and have fractured surfaces parallel to each other at both ends of the member, and a pair of legs that extend between these legs and form a stepped shape with respect to the plane that includes one of the fractured surfaces. A bent fixing piece and a mounting leg formed near the other fracture surface of both leg pieces and bent at a position away from the fracture surface are provided, and the magnetic sensor is placed in contact with the fracture surface on one side. A magnetic rotary rotor, characterized in that the holding member is bonded to the fixing piece in a state in which the holding member is in contact with the reference plane part, and the mounting leg part is screwed with the fractured surface on the other side in contact with the reference plane part. encoder.