JPS59155716A - Rotary encoder - Google Patents

Abstract

PURPOSE:To make it possible to secure a rotary slig plate to a rotary shaft by concentrically determining the pattern position of the rotary slit plate without using a jig for performing positiolnal alignment and not necessitating the processing accuracy of a center hole at all, by securing the pattern of the rotary slit plate to the rotary shaft through an attachment member in concentrically coincided relation to said rotary shaft. CONSTITUTION:An attachement member 4 is attached to the shaft end 2a of a rotary shaft 2 in such a state that said rotary shaft 2 is pivotally supported by a main body 1 while the other end 2b of the rotary shaft 2 is geared into a processing machine in this state and the outer peripheral end surface 4a of the attachement member 4 is processed while the rotary shaft 2 is rotated at a desired speed to form a radius (r) (r=a) coincided with the radius (a) of the aligning mark M which is applied in concentrical relation to the pattern P of a rotary slit plate 5. As mentioned above, by performing processing on the basis the rotary shaft 2, the eccentric amount of the outer peripheral end surface 4a of the rotary shaft 2 is suppressed. Thereafter, the rotary slit plate 5 is temporarily clamped on the attachement member 4 by a press plate and a screw and the aligning mark M of the rotary slit plate 5 is allowed to coincide with the outer peripheral end surface 4a of the attachement member 4.

Description

[Detailed Description of the Invention] The present invention relates to a rotary encoder that photoelectrically detects the rotation angle, rotation speed, or linear displacement of an object to be measured. Akira・
The present invention relates to a low-resolution encoder in which a dark pattern is precisely placed and fixed concentrically with respect to a rotation axis.

This type of photoelectric rotary encoder consists of a rotating slit plate fixed to a rotating shaft supported by the main body, a fixed slit plate fixed to the main body in proximity to the rotating slit plate, and a pair of slit plates. The light-emitting and light-receiving elements are arranged opposite to each other with the rotating shaft and the rotating slit plate.
If there is an eccentricity between the circumference and the dark pattern,
During the rotation of the rotary shaft, the characteristics of the output signal obtained from the light-receiving element vary, making it impossible to obtain high precision. Therefore, during assembly, it is especially important to avoid eccentricity between the rotary shaft and the pattern circumference of the rotary slit plate. It was necessary to do so.

Therefore, as a conventional measure to reduce this amount of eccentricity, (1) Use a jig to position a fixed slit plate with respect to the rotating shaft, and then use this positioned fixed slit plate as a reference to look into the microscopic area and open the rotating slit. (2) The center hole of the rotating slit plate is precisely set concentrically to the circumference on which the light and dark patterns are applied (for example, ±10.L). The method used was to position the shaft by machining it (below) and inserting this center hole into the matching shaft part of the rotating shaft.

However, in the former method, the fixed slit plate is fixed using a special jig, and the rotating slit plate is fixed concentrically with respect to the rotation axis based on this fixed slit plate. Even if the rotating slit plate can be positioned extremely accurately, if the fixed slit plate is eccentrically fixed with respect to the rotating shaft, eccentricity between the rotating slit plate and the rotating shaft cannot be avoided. ,
Furthermore, since a jig is used to position the fixed slit plate itself, some eccentricity with respect to the rotating shaft occurs.

In the latter method, the rotary slit plate is directly fixed using the rotary shaft as a guide without using the fixed slit plate as a reference, so it can be used quickly (and even accurately), regardless of the operator's skill level. However, the center hole and the pattern circumference must be machined in advance to be concentric with a considerable degree of accuracy, which is disadvantageous in that the cost increases significantly. .

In view of the above-mentioned drawbacks, the present invention has been made in view of the above-mentioned drawbacks. The object of the present invention is to provide a rotary encoder that can concentrically position the pattern of the rotary slit plate and fix the rotary slit plate.

The ninth aspect of the invention to achieve the above object is as stated in the Claims section above.

Next, preferred embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an explanatory longitudinal cross-sectional view of a main part of a rotary encoder according to the present invention, and FIG. 2 is an explanatory view of a main part for positioning a rotary slit plate on the rotation axis in FIG.

In these figures, 1 is the main body, 2 is the rotating shaft, and a pair of ball bearings 1 are provided in the center hole of the main body 1.
a, 11] It is rotatably mounted on the shaft.

Lo is a spacer ring, a pair of ball bearings 1a,
11) The bearings 1a and 11 are interposed between the bearings 1a and 11 to regulate the spacing. 4 is a mounting member for fixing a rotating slit plate 5, which will be described later, and is attached to one shaft end 2a (I) of the rotating shaft 2.
T! They are integrally fixed by appropriate means such as IN press-fitting, adhesion, and screwing. 5 is a rotating slit plate made of metal material such as glass, acrylic, or stainless steel, and as shown in Fig. 2, two circles (6
D, and within the area determined by the rooster are bright and
A well-known pattern P, which is alternately dark and consecutively provided at 19 intervals, is applied. Furthermore, for one circle that determines this pattern P, for example φD, a concentric circumference (
An alignment mark M is provided at the radius (indicated by radius a in FIG. 2). In Fig. 2, this alignment mark M is
Although shown as a line corresponding to a circle with radius a, in FIG. 6 shown as another example, a plurality of lines)
One of them is shown as (shown in the figure), and the inner arc of this slit M is formed so as to coincide with a circle of radius a.

Reference numeral 6 is a fixed slit plate, similar to the rotating slit plate 5.
On the circumference of the rotating slit plate 5, which matches the pattern P, there are two sets of known slit patterns (not shown) that are bright and dark against light and are alternately spaced at regular intervals and have a phase difference with each other. It is fixed to the main body 1 in close proximity to the rotary slit plate 5 via a holding member 7. Reference numeral 8.9 denotes a light emitting element and a light receiving element which are arranged facing each other with the pair of slit plates 5.6 in between.

Next, a method for fixing the pattern P of the rotating slit plate 5 concentrically to the rotating shaft 2 will be explained.

With the rotating shaft 2 supported on the main body 1, the shaft end 2 of the rotating shaft 2
3. Attach the mounting member 4 several times, and in this state, attach the shaft end 21 of the rotary shaft 2 to a processing machine such as a lathe or grinder, and while rotating the rotary shaft 2 at a desired speed, attach the mounting member 4.
By cutting or grinding the outer peripheral end surface 4a of the rotary slit plate 5, a radius r (sflc, ra-a
).

By processing the rotary shaft 2 as a base in this manner, the eccentricity of the outer peripheral end surface 4a of the shaft member 4 can be sufficiently suppressed to within 10 μm. After that, the rotating slit plate 5 is
The holding plate 10 and the screws 11 are used to temporarily fix the rotating slit plate 5 to the mounting member 4'' so that the alignment mark M of the rotating slit plate 5 coincides with the outer circumferential end surface 4a of the mounting member 4.

Furthermore, if the upper plane 41) of the mounting member 4 is also machined at the same time when the outer peripheral end face 4a of the take-out member 4 is machined, the perpendicularity of the upper plane 41) to the rotating shaft 2 can be ensured with the accuracy of the town. It is also possible to eliminate flat vibration of the rotating slit plate 4 with respect to the rotating shaft 2 when the rotating slit plate 4 is attached.

In the previous embodiments, a circle or a long hole shape was shown as the alignment mark M, but a circle (radius a) concentric with the pattern P [therefore, a continuous circle on the determined n circumference] (・ is applied discontinuously, or a part of the alignment mark M should match, and the mounting member 4 that is machined to match this radius a may also be Instead of the length of the outer circumferential end surface 4a, as shown in FIG. 4, it may be formed as the inner circumferential surface 4d of the groove 4C (of course, it may be on the outer circumferential side).

As explained in detail above, the present invention forms a circumferential surface on a mounting member fixed to a rotating shaft that matches the circumference of a alignment mark made concentrically with the pattern of a rotating slit plate, If you align the circumferential surface with the alignment mark and fix it as is, you can fix it with extreme precision.
It is possible to provide a highly accurate and inexpensive rotary encoder with less eccentricity without using a dedicated jig or requiring extremely high machining accuracy as in the past.

[Brief explanation of the drawing]

FIG. 1 is an explanatory view of a main part in longitudinal section of a rotary encoder according to an embodiment of the present invention, FIG. 3
FIG. 4 is a plan view illustrating a main part of another embodiment of the alignment mark of the rotary slit plate, and FIG. 1 Main body, 2. Rotating shaft, 4.-Mounting member, 4a, 4d.
・Circumferential surface, 5 ・Rotating slit plate, P... pattern, M
Alignment mark, 6 Fixed slit plate, 8・Light emitting element, 9
Light-receiving element, ward C difficult procedure correction M)] Commissioner of the Japan Patent Office Kazuinu Wakasugi 1, Indication of the case Patent Application No. 031244 of 1982 2, Name of the invention Rotary encoder 3, Person making the amendment Telephone number 055 .5-3-1231 Voluntary action 5. No increase in the number of inventions due to the amendment 6. Column 7 of "Detailed explanation of the invention" of the specification subject to the amendment, Line 3 of page 7 of the description of the contents of the amendment Correct the phrase ``in addition'' to ``in addition to the opportunity.''

Claims (1)

[Scope of Claims] A rotating slit plate fixed to a rotating shaft supported by the main body and having a continuous pattern of bright and dark on the circumference, and a rotating slit plate in the vicinity of the rotating slit plate, which is attached to the main body. A rotary encoder comprising: a fixed slit plate fixed to a fixed slit plate with a wide pattern of bright and dark; and a light emitting element and a light receiving element disposed opposite to each other with the pair of slit plates sandwiched therebetween; A alignment mark is made on a circumference concentric with the light/dark pattern, and a circumferential surface having the same size as the circumference on which the alignment mark is made is formed. A rotary encoder, comprising: a mounting member, so that the pattern of the rotary slit plate is concentrically aligned with and fixed to the rotation shaft via the mounting member.