JP2004151076A - Rotatable component for hub-integrated reflection type optical encoder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotatable component for a reflection type optical encoder with an integrated hub. <P>SOLUTION: The rotatable component for a reflection type optical encoder turns the irradiated light into an encoded reflection light by a rotatable component which comprises a reflecting surface and a non-reflecting surface, or comprises two or more kinds of reflecting surfaces with different reflection characteristics. The rotatable component comprises a hub fixed to a rotating shaft of a motor. The reflecting surface, non-reflecting surface, or two or more reflecting surfaces with different reflection characteristics is provided on the plane vertical to the rotating shaft of the hub. Since it is fixed to the rotating shaft of the motor itself with no need of fixing to another component, for a smaller size, no deviation of the rotating shaft, delay in response to the rotating shaft or loosening, nor wearing of a part is hard to occur, resulting in longer life of a product, with less consumption of energy. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
[Industrial applications]
The present invention relates to a rotary component for a reflective optical encoder integrated with a hub of a rotary motor.
[0002]
[Prior art]
The optical encoder uses a rotating part with a number of thin slits formed on a thin metal plate, which allows the transmission of irradiation light by the slits or irradiates the light by blocking it with a metal plate between the slits. Light has been converted to encoded light. In recent years, there is a limit in accuracy when a slit is formed by etching, and a reflection type optical encoder is also used.
[0003]
The precision metal part for the reflective part of the reflective optical encoder encodes the illuminated light by having a reflective surface and a non-reflective surface, or by having a plurality of reflective surfaces having different reflective characteristics from each other. To the reflected light. A method for manufacturing such a reflective optical encoder component is described in, for example, JP-A-2000-283794.
[0004]
[Problems to be solved by the invention]
However, conventional optical encoders, whether they allow or block the transmission of light or encode by reflection or non-reflection, use special parts that are generally thin metal. . Perhaps the reason is that precision parts are relatively expensive, have a simple structure like a hub commonly used for fixing parts to the motor shaft, and are inexpensive due to the large number of off-the-shelf products manufactured. Since it is common sense to manufacture separately from parts, it is difficult to precisely process a three-dimensional structure such as a hub, which is not a thin plate, in actual manufacturing Because.
[0005]
When an optical encoder is manufactured by fixing a thin metal plate to a hub, the thin metal plate tends to have insufficient strength for movement such as rotation and handling during assembly if the proportion of the thin metal portion is too large. Therefore, it is necessary to fix the hub to a firm hub.
[0006]
On the other hand, the use of thick special metal components only for encoding purposes requires extra space and results in energy loss.
[0007]
[Means to solve the problem]
The present inventors have as follows: 1) If a metal part is manufactured by the method described in JP-A-2000-283794, a reflection surface or the like can be provided at a considerable place of an existing part. 2) On the other hand, focusing on the fact that a rotary encoder uses a motor as a power, and the motor usually uses a) a rotating shaft and b) a hub, a hub-integrated reflective optical system The inventors have found that the above problem can be solved by a rotary component for an encoder, and have completed the present invention.
[0008]
That is, the present invention provides a reflection type in which light to be irradiated is reflected by a rotating component having a reflection surface and a non-reflection surface or having two or more reflection surfaces having different reflection characteristics from each other. In a rotary component for an optical encoder, the rotary component is a hub fixed to a rotating shaft of a motor, and the reflection surface and the non-reflection surface, or two or more reflection surfaces having different reflection characteristics from each other are provided. And a rotary part for a reflective optical encoder, which is provided on a plane perpendicular to the rotation axis of the hub.
[0009]
Material The material of the rotary component for the reflective optical encoder of the present invention is not particularly limited as long as it can form a reflective surface and a non-reflective surface, but is generally based on brass or stainless steel. It is convenient to use a hardened aluminum alloy, and an aluminum alloy or iron can be used. Furthermore, the present inventors have conducted studies to further reduce energy loss, and as a result, the hub is made of a lightweight magnesium alloy as a main material, or is made of synthetic resin or plastic whose surface is metal-plated, It has been discovered that energy loss can be reduced by forming the reflective surface and the non-reflective surface or two or more reflective surfaces having different reflective characteristics on the metal plated portion. Compared with the conventionally used brass (specific gravity 8.39) and aluminum (specific gravity 2.70), the specific gravity of magnesium is about 1.8, which is the smallest among practical metal materials, 2/3 of aluminum, and 1 of titanium. / 3, 1/4 of iron, and the physical properties of the alloy are also suitable for the purpose of the present invention. Therefore, the book for the purpose of reducing energy loss, especially the load at the time of starting and stopping the motor, is preferred. It is excellent as a material of the rotary component for the reflective optical encoder of the present invention. Also, a method of attaching a metal in a desired pattern on the surface of a three-dimensional synthetic resin or plastic object is known. (See, for example, Japanese Patent No. 2776791, Japanese Patent No. 2951843, etc.)
[0010]
Example of reflective surface The reflective surface and the non-reflective surface, or two or more reflective surfaces having different reflective characteristics from each other, of the rotary component for the reflective optical encoder include, for example, those having the following forms. I can do it.
[0011]
B) at least a light reflection surface portion on a surface perpendicular to the rotation axis of the hub is made of a metal or alloy having a plurality of layers formed of at least two or more metals or alloys;
The light-reflecting surface portion on the surface perpendicular to the rotation axis of the hub may be partly a light-reflective surface and partly a non-light-reflective surface or two or more reflective surfaces having different reflection characteristics from each other. Yes,
The light reflecting surface portion has a predetermined pattern portion in which the metal or alloy on the surface does not exist because at least one layer of a metal or alloy different from the metal or alloy on the surface is exposed. thing.
[0012]
B) In the above item a), only the metal or alloy portion on the surface of the light reflecting surface portion, or only the exposed portion of the metal or alloy different from the metal or alloy on the surface of the light reflecting surface portion. , With a metal oxide film formed to eliminate light reflection or reduce light reflection. Here, as the metal oxide film, a process for forming a black oxide film generally called a black oxide process can be used. For example, a thin film of copper oxide can be formed. Also, triiron tetroxide can be used for blackening.
[0013]
C) a light-reflecting surface portion on a surface perpendicular to the rotation axis of the hub, the portion being a light-reflecting surface and another being a non-reflective surface, or having different reflection characteristics from each other; The surface of the first metal or alloy has a concave portion of a predetermined pattern, and the first metal or alloy is formed in the concave portion of the predetermined pattern. And at least one selected from the group consisting of at least one metal or alloy different from the first metal or alloy having a metal oxide film on the surface and at least one metal or alloy different from the first metal or alloy. thing.
[0014]
D) A light reflecting surface portion on a plane perpendicular to the rotation axis of the hub is a single metal or alloy reflecting layer, and a predetermined pattern on the surface of the reflecting layer or a predetermined pattern existing on the surface of the reflecting layer A metal oxide film as described above for eliminating or reducing light reflection on the surface of the concave portion.
[0015]
Examples of manufacturing method of reflective surface portion For example, the methods a) and b), c) and d) described in JP-A-2000-283794 are exemplified.
I)
A resist was applied to the first metal or alloy layer side of a thin metal plate or film having a first metal or alloy layer and a second metal or alloy layer, and only a predetermined pattern of the resist was removed. Forming a resist layer;
Etching the first metal or alloy with a corrosive liquid to remove the second metal or alloy layer into the surface of the first metal or alloy layer; Exposed with;
Performing a process of forming an oxide film of the second metal or alloy on the exposed surface of the second metal or alloy layer to reduce or eliminate light reflection;
Thereafter, the resist layer is removed;
A method comprising the steps described above, wherein the surface of the first metal or alloy layer is a surface that reflects light, and the oxide film of the second metal or alloy is a surface that does not reflect light. . (See Fig. 7)
B)
A resist is applied to the reflective surface where the first metal or alloy of the metal material is exposed to form a resist layer in which only a predetermined pattern of the resist is removed;
After the concave portion is formed by etching a predetermined pattern portion of the reflection surface portion where the resist is removed, or to the next step without forming a concave portion without etching,
Plating a metal different from the metal or alloy on the exposed surface of the metal or alloy from which only the predetermined pattern has been removed to form portions of different metal or alloy;
If the different metal or alloy portion is not used as a light reflecting surface, a dark oxide of the different metal or alloy is applied to the surface of the plated different metal or alloy portion to reduce or eliminate light reflection. Performing a process of forming a film of;
Removing the resist layer;
Polish only when polishing is necessary,
A method in which at least one of the plurality of types of metals or alloys is a surface to which light is to be reflected, comprising performing the above steps more than once by changing the predetermined pattern once or more times. (See Fig. 9)
C) applying a resist in a desired pattern on the base material forming surface;
Forming a first metal layer having a thickness equal to or less than the thickness of the resist, that is, the height from the formation surface, by electroforming or other thin film forming methods in contact with the surface of the base material not covered with the resist; Stages and
A second metal layer is formed by electroforming or other thin film forming method so as to cover the first metal layer and the resist, and if necessary, a reinforcing layer is further formed on the second metal layer. Forming a
Stripping and / or removing the base material and the resist from a metal component including the first metal layer and the second metal layer;
And
One of the first metal layer and the second metal layer exposed by the peeling and / or removal is a reflection surface, and the other is a non-reflection surface, or the first metal layer is A method wherein the second metal layer is a reflective surface having different reflective properties. (See FIG. 14)
D)
A step of applying a resist in a desired pattern on the base material forming surface,
Forming a metal layer having a thickness equal to or less than the thickness of the resist by electroforming or another thin film forming method in contact with the formation surface of the base material not covered with the resist,
Providing a reinforcing portion in contact with the metal layer before removing the base material and the resist;
Peeling and / or removing the base material and the resist from the metal layer, so that a penetration portion is not formed by peeling and / or removing the base material and the resist. Features method. (See FIG. 15)
[0016]
【Example】
Hereinafter, the present invention will be described with reference to the drawings.
FIG. 1 is a plan view of a hub of a motor which also serves as a rotating part for a reflective optical encoder according to the present invention, FIG. 2 is a front view of the hub of FIG. 1, and FIG. 3 is fixing the hub of FIG. FIG. In the case of the rotary component for the reflective optical encoder of FIG. 1, the reflective surface and the non-reflective surface provided on the surface perpendicular to the rotation axis of the hub or two or more reflective surfaces having different reflective characteristics from each other are: They are arranged in a manner resembling elongated, alternating close slits, all oriented radially to a central axis. However, the reflection surface and the non-reflection surface provided on the surface perpendicular to the rotation axis of the hub, or two or more reflection surfaces having different reflection characteristics from each other can be arranged in any form according to the purpose of the encoder. .
[0017]
The rotating part, that is, the hub 1 can have various shapes as shown in FIGS. 2, 5 and 6, but has a large radius portion 2 and a small radius portion 3 in the case of FIG. . The whole center has a hole 4 through which the shaft of the motor passes. FIG. 3 shows an appropriate method, such as screwing a set screw into a screwed set screw hole as shown in FIG. 2 and fixing the set screw by abutting the tip of the set screw on the peripheral surface of the motor shaft. As shown, hub 1 is fixed to shaft 6 of motor 5. In the example of FIG. 2, the large radius portion 2 has surfaces 7, 8 perpendicular to the rotation axis on both sides thereof, and in FIG. 3 a surface 7 perpendicular to the rotation axis opposite to the motor 5, or FIG. In the case of No. 4, a portion 9 having a slit-shaped reflecting surface and a non-reflecting surface is provided on the surface 8 or on both the surfaces 7 and 8. When both sides have a portion having a reflection surface and a non-reflection surface, as shown in FIGS. 3 and 4, the slit pattern can be selectively used according to the mounting direction of the hub to the motor shaft.
[0018]
The production of the reflective surface and the non-reflective surface of the hub 1 or two or more reflective surfaces having different reflective characteristics from each other can be performed by an arbitrary method described in JP-A-2000-283794, a method using the base material described above. Or any other method.
[0019]
【effect】
The present invention has the following advantages.
1) By integrating the hub and the encoder parts, space can be saved, and the encoder can be downsized.
2) It is not necessary to attach a thin precision metal plate such as a metal plate having a slit-shaped reflection pattern to another part such as a hub by bonding, press-fitting, or other methods, and it is considered that the number of steps can be reduced.
3) Since the hub is fixed to the rotating shaft of the motor itself, displacement of the rotating shaft, delay or loosening of the response to rotation, and wear of parts are less likely to occur, which contributes to prolonging the life of the product.
4) Energy consumption is saved because it does not drive a separate component from the motor.
[Brief description of the drawings]
FIG. 1 is a plan view of a rotating component for a hub-integrated reflective optical encoder of the present invention in a general form.
FIG. 2 is a front view of the rotary component for a hub-integrated reflective optical encoder of the present invention shown in FIG. 1;
FIG. 3 is a schematic view showing a state in which the hub of FIG. 1 is fixed to a motor.
FIG. 4 is a schematic view showing a state in which the hub of FIG. 1 is fixed to a motor in a direction opposite to that of FIG. 3;
FIG. 5 is a front view of a hub different from FIG. 2 in that it has the same diameter over its entire length.
FIG. 6 is a front view of yet another form of hub.
FIG. 7 is an explanatory view showing a step of manufacturing one specific example of the encoder component of the present invention by a cross-sectional view of the component.
FIG. 8 is an explanatory view showing a step of manufacturing another specific example of the encoder component of the present invention by a cross-sectional view of the component.
FIG. 9 is an explanatory view showing a step of manufacturing another specific example of the encoder component of the present invention by a cross-sectional view of the component.
FIG. 10 is an explanatory view showing a step of manufacturing another specific example of the encoder component of the present invention by a cross-sectional view of the component.
FIG. 11 is a sectional view showing another specific example of the encoder component of the present invention.
FIG. 12 is an explanatory view showing a step of manufacturing another specific example of the encoder component of the present invention by a cross-sectional view of the component.
FIG. 13 is a sectional view showing another specific example of the encoder component of the present invention.
FIG. 14 is a process drawing showing the steps of manufacturing an example of the method for manufacturing a precision metal part according to the present invention in a cross section of the part.
FIG. 15 is a process diagram showing, in cross-section, a part of each step of an example of another method of manufacturing a precision metal part according to the present invention.
FIG. 16 is a diagram illustrating a case where a component made of a metal plate is manufactured by an electroforming method using a resist using a base material, and a case where the component is manufactured by etching from a metal plate having a center hole or the like in advance; FIG. 9 is an explanatory view showing a comparison of component manufacturing processes, explaining that a pattern including a center hole and an outline can be determined by a photograph, so that troublesome positioning of a film or the like can be omitted.

Claims (13)

A rotary component for a reflective optical encoder that converts the irradiated light into reflected light encoded by a rotary component having a reflective surface and a non-reflective surface or two or more reflective surfaces having different reflective characteristics from each other. At
The rotating component is a hub that can be fixed to a rotation axis of a motor, and the reflection surface and the non-reflection surface or two or more reflection surfaces having different reflection characteristics are provided on a surface perpendicular to the rotation axis of the hub. A rotating part for a reflective optical encoder, comprising: 2. The rotating component according to claim 1, wherein a light-weight magnesium alloy is used as a main material, and the reflection surface and the non-reflection surface or two or more reflection surfaces having different reflection characteristics are formed on the magnesium alloy. 2. The rotating component according to claim 1, wherein the surface is made of metal-plated plastic, and the metal-plated portion is provided with the reflection surface and the non-reflection surface or two or more reflection surfaces having reflection characteristics different from each other. At least the light reflecting surface portion on the surface perpendicular to the rotation axis of the hub is made of a metal or alloy having a plurality of layers formed of at least two or more metals or alloys,
The light-reflecting surface portion on the surface perpendicular to the rotation axis of the hub may be partly a light-reflective surface and partly a non-light-reflective surface or two or more reflective surfaces having different reflection characteristics from each other. Yes,
The light reflecting surface portion has a predetermined pattern portion in which the metal or alloy on the surface does not exist because at least one layer of a metal or alloy different from the metal or alloy on the surface is exposed. The rotating component according to claim 1. To eliminate reflection of light only on the metal or alloy portion of the surface of the light reflecting surface portion or only on the exposed portion of the metal or alloy different from the metal or alloy on the surface of the light reflecting surface portion, or 5. The rotating component according to claim 4, wherein a metal oxide film is formed to reduce the reflection of light. A light-reflecting surface portion on a surface perpendicular to the rotation axis of the hub, the portion being a light-reflecting surface and another being a non-reflective surface, or two types having different reflection characteristics from each other; The above reflection surface, the structure below the surface of the portion, the surface of the first metal or alloy has a recess of a predetermined pattern, in the recess of the predetermined pattern, the first metal or alloy and the A structure having at least one selected from the group consisting of at least one different metal or alloy and at least one metal or alloy different from the first metal or alloy having a metal oxide film on the surface. The rotating part according to claim 1, characterized in that: A reflective layer of a single metal or alloy, for eliminating or reducing light reflection on a predetermined pattern on the surface of the reflective layer or on a concave surface of a predetermined pattern present on the surface of the reflective layer. The rotating component according to claim 1, wherein a metal oxide film is formed. A step of applying a resist in a desired pattern on the base material forming surface,
Forming a first metal layer having a thickness equal to or less than the thickness of the resist, that is, the height from the formation surface, by electroforming or other thin film forming methods in contact with the surface of the base material not covered with the resist; Stages and
A second metal layer is formed by electroforming or other thin film forming method so as to cover the first metal layer and the resist, and if necessary, a reinforcing layer is further formed on the second metal layer. Forming a
Stripping and / or removing the base material and the resist from a metal component including the first metal layer and the second metal layer;
And
One of the first metal layer and the second metal layer exposed by the peeling and / or removal is a reflection surface, and the other is a non-reflection surface, or the first metal layer is 2. The method for manufacturing a rotating component according to claim 1, wherein the second metal layer has a reflection surface having a different reflection characteristic. The first metal is nickel, the second metal is copper, a metal layer is formed by electroforming, and copper plating for forming the second metal layer is performed. 9. The rotating component of claim 8, starting from the nickel surface at a location below the top surface of the resist and growing over at least the entire top surface of the resist until copper is fully connected. The rotating component according to claim 9, wherein the surface of the nickel layer forms a reflection surface, and the exposed surface of the copper layer is blackened to form a non-reflection surface. 9. The rotating component according to claim 8, wherein the first metal is nickel, and the second metal layer is a metal layer formed by a black nickel plating method. A step of applying a resist in a desired pattern on the base material forming surface,
Forming a metal layer having a thickness equal to or less than the thickness of the resist by electroforming or another thin film forming method in contact with the formation surface of the base material not covered with the resist,
Providing a reinforcing portion in contact with the metal layer before removing the base material and the resist;
Peeling and / or removing the base material and the resist from the metal layer, so that a penetration portion is not formed by peeling and / or removing the base material and the resist. The rotating component according to claim 1, wherein the rotating component is manufactured by a method for manufacturing a precision metal component. The base material has a mirror surface as the formation surface, and the base material is made of stainless steel or glass which may have a metal thin film and / or a release coating film. Rotating parts described in the above.

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