JP2555068Y2 - Encoder - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an encoder.

[0002]

2. Description of the Related Art A conventional encoder of this type has a structure as shown in FIG. In FIG. 2, the glass scale 32
An incremental pattern of light and dark is repeatedly formed at a constant angular width on the peripheral portion of the rotary shaft 31.
A glass surface portion on which no pattern is formed is bonded and fixed on 3. The rotating shaft 31 is connected to a fixed member 35 via a bearing 36, and the rotating shaft 31 is configured to freely rotate with respect to the fixed member 35. A light emitting unit 37 and a light receiving unit 38 are arranged on the fixing member 35 with the incremental pattern of the glass scale 32 interposed therebetween. The light emitting unit 37 and the light receiving unit 38 constitute a detector that reads the amount of movement of the incremental pattern. Note that the index scale 38a of the light receiving section 38 faces the incremental pattern formed on the glass scale 32.

[0003]

In the prior art as described above, since glass and metal are bonded with an adhesive, there is a problem that stable adhesive strength cannot be obtained. Therefore, an object of the present invention is to obtain an encoder in which a glass scale is bonded to a metal support with stable bonding strength.

[0004]

In order to solve the above problems, the present invention provides an encoder for reading a pattern of a glass scale fixed to a support using a detector which moves relatively to the scale. An encoder, wherein the support is formed of metal, chromium is vapor-deposited on the scale to form a surface to be bonded, and the scale is bonded and fixed to the support through the surface to be bonded. did.

[0005]

[Function] In the present invention, chromium is vapor-deposited on the glass surface to form a metal-bonded surface, so that metals can be bonded to each other with an adhesive, and the glass scale is bonded to the support with stable bonding strength. The obtained encoder can be obtained. Note that the adhesion strength between glass and chromium is sufficiently higher than the adhesion strength between the adhesive and the metal.

[0006]

FIG. 1 shows a glass scale 1 according to an embodiment of the present invention.
1, which is used instead of the glass scale 32 in FIG. Since the glass scale of FIG. 1 has two types of patterns, an M-sequence pattern and an incremental pattern, it is necessary to change the detector of FIG. 2 to a detector that reads these well-known patterns.

The glass scale 11 shown in FIG. 1 has an incremental track 13 having an incremental pattern formed on the outermost periphery, and an M-sequence track 13b having an M-sequence pattern formed therein. In the incremental pattern, bright and dark gratings are arranged at equal angles, and in the M-sequence pattern, bright and dark patterns are arranged so that digital codes having different combinations can be obtained at predetermined angles in the circumferential direction. A through-hole 14 is formed in the center, and a chromium-deposited surface 12 for bonding is provided around the through-hole 14.

[0008] The chromium deposition surface 12 is
b M-sequence pattern and incremental track 13
Is formed at the same time when the incremental pattern is formed using chromium. That is, chromium is vapor-deposited on the entire surface of the glass surface, and the chromium-deposited surface 12 for bonding may be left when the M-series pattern and the incremental pattern are etched.

Therefore, in this case, the M series pattern and the incremental pattern and the chromium deposition surface 12 for bonding are used.
Are formed on the same surface. On the chromium deposition surface for bonding,
The adhesive is fixed on the support 33 of the rotating shaft 31 in FIG. 2 with an epoxy-based adhesive. The rotating shaft 31 is formed of a metal such as stainless steel.

[0010] With such a structure, in the above embodiment, the chromium deposition surface 12 for bonding is formed in the same step as the pattern for measuring the amount of movement, so that a special step is required to form the deposition surface 12. There is no need to cross. Since the glass scale 11 is bonded and fixed to the support base 33 with an adhesive via a chromium vapor-deposited surface, the bonding strength is stable with respect to environmental changes (humidity, temperature, etc.) Adhesion strength is increased by 1.5 to 2 times as compared with the time.)

In the above embodiment, the chromium deposition surface 1
2 does not have to be formed in the same step as the pattern.
In this case, it is not necessary to form the chromium deposition surface 12 and the pattern on the same surface. Even in this case, it is not necessary to change the type of process between the pattern formation and the deposition surface formation, so the cost increase is not so large. Also, the adhesive may be any as long as it can bond metal, and there is no need to stick to epoxy.

Further, in the above embodiment, a ring-shaped scale for a rotary encoder is taken as an example of a glass scale, but it is obvious that the present invention can be applied to a plate-shaped scale for a linear encoder.

[0013]

According to the present invention, as described above, since chromium deposition is applied to a glass bonding surface to bond metal to metal, it is not a different kind of bonding such as bonding glass to metal. Better adhesion. In addition, since chromium vapor deposition has been conventionally used when forming an encoder pattern, there is also an advantage that there is almost no element of cost increase.

[Brief description of the drawings]

FIG. 1 is a plan view of a glass scale according to an embodiment of the present invention.

FIG. 2 is a sectional view of a conventional rotary encoder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Glass scale 12 Chromium vapor deposition surface 13 Incremental track 13b M series track 14 Through hole 31 Rotation axis 32 Glass scale 33 Support base 35 Fixing member 36 Bearing 37 Light emitting part 38 Light receiving part 38a Index scale

Claims (2)

(57) [Scope of request for utility model registration] 1. An encoder which reads a pattern of a glass scale fixed to a support using a detector which moves relatively to the scale, wherein the support is formed of metal and chrome is formed on the scale. Wherein the scale is bonded and fixed to the support via the surface to be bonded. 2. The encoder according to claim 1, wherein the surface to be bonded and the pattern are simultaneously formed on the same surface of the glass scale by vapor deposition of chromium.