JPH04372546A - Stepping motor - Google Patents

Abstract

PURPOSE:To increase an output of a stepping motor of equal structure with improvement in an effect of collecting and radiating heat by applying an anodic oxidation film of black color to brackets of the stepping motor. CONSTITUTION:In the case of a stepping motor 1 having brackets 7, 8 for holding a stator core 2 in a predetermined position while rotatably supporting a rotary shaft 4 of a rotor 3, anodic oxidation films 10, 11 of black color are applied to surface of the brackets 7, 8.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention relates to a stepping motor, and particularly to a stepping motor that rotatably supports a rotating shaft of a rotor.
This invention relates to a stepping motor in which a black anodic oxide film (hereinafter referred to as alumite) is applied to the surface of a bracket that holds a stator in a predetermined position.

0002

2. Description of the Related Art Generally, stepping motors are known that have a bracket that rotatably supports a rotating shaft of a rotor and holds a stator in a predetermined position. The bracket is often formed by die-casting using an aluminum alloy. Brackets include those whose surfaces are as cast, those whose surfaces are finished by shot blasting after casting, and those whose surfaces are finished by shot blasting and then painted. FIG. 4 shows a conventional stepping motor with a painted bracket. The stepping motor 21 is arranged with a stator core 22 and inside the stator core 22,
It has a rotor 23 that rotates by interaction with the rotating magnetic field of the stator. A rotating shaft 24 of the rotor 23 is rotatably supported by brackets 27 and 28 via ball bearings 25 and 26. Bracket 27,2
8 further sandwiches the stator core 22 and holds the stator core 22 in a predetermined position. The stator core 22 has a coil 2
9 is wound to form a stator. Bracket 27
, 28 has a coating film 3 of black paint on the outer surface of the stepping motor 21 in order to more efficiently release the heat inside the stepping motor 21.
It has 0. On the other hand, brackets 27, 28
The coating film is removed from the inner surface 31 of the stator core 22 and the ball bearings 25, 26 in order to accurately mount the stator core 22 and ball bearings 25, 26 in predetermined positions.

0003

[Problems to be Solved by the Invention] However, since the surface of the conventional bracket whose surface is as-cast or whose surface has been finished by shot blasting etc. is metallic, it is difficult to use it with a stepping motor. When used in a stepping motor, the heat collection and heat dissipation effect for the stepping motor is low. Due to the low heat collection and heat dissipation effects of the bracket, the power that can be input to the stepping motor is limited, resulting in a problem that the efficiency of the stepping motor is poor. In addition, the above black painted bracket is
Since paint is usually applied by spraying, dipping, etc.
Paint adheres to the inside surface of the bracket. However, due to the miniaturization of steppin motors, strict dimensional accuracy of the inner surface of the bracket is required, and the dimensions of the inner surface of the bracket are affected by the coating film formed by the paint adhering to the inner surface of the bracket. Therefore, conventionally, the paint film adhering to the inner surface of the bracket has been removed by mechanical or chemical methods, which takes time and complicates the manufacturing process of the stepping motor. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a stepping motor that has a bracket that has high heat collection and heat dissipation effects, is easy to manufacture, and has high efficiency.

0004

[Means for Solving the Problems] In order to achieve the above object, a stepping motor of the present invention has a bracket that rotatably supports a rotating shaft of a rotor and holds a stator in a predetermined position. The bracket is characterized in that a black anodic oxide film is applied to the surface of the bracket.

[0005]

[Operation] In the stepping motor of the present invention, the surface of the bracket is coated with black alumite. This black alumite oxide film is strong and has a high heat collection and heat dissipation effect, so stepping motors with black alumite brackets have a smaller temperature rise than motors with the same structure and a large rated capacity. By having this, the efficiency of the motor can be increased. In addition, the bracket according to the present invention has high corrosion and abrasion resistance due to the dense structure of black alumite, and can protect the stepping motor from external forces, and can be used under severe conditions such as corrosion and abrasion. can do. Furthermore, in black alumite, metals or metal oxides are deposited in the recesses of the anodic oxide film of the alumite during electrolysis and are colored black, so that the shape and dimensions of the bracket surface will not change due to paint or the like. Therefore, it is not necessary to perform operations such as polishing to remove the colored layer on the inner surface of the bracket after coloring, and manufacturing is easy.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a cross section of a stepping motor having a bracket coated with black alumite in the direction of the rotating shaft. The stepping motor 1 has a stator core 2
and a rotor 3 that is arranged inside the stator core 2 and rotates by interaction with the rotating magnetic field of the stator. The rotor 3 is penetrated by the rotating shaft 4 and is configured to rotate together with the rotating shaft 4. Both ends of the rotating shaft 4 are rotatably supported by brackets 7 and 8 via ball bearings 5 and 6, and the brackets 7 and 8 further sandwich the stator core 2 and hold the stator core 2 in a predetermined position. There is. A coil 9 is wound around the stator core 2,
It constitutes a stator that generates a rotating magnetic field by switching the current. The brackets 7 and 8 have black alumite 10 and 11 on their surfaces. This black alumite 1
0, 11 are formed on the entire surface of the brackets 7, 8,
It is also formed on the contact surface between the stator core 2 and the coil 9 or the contact surface between the stator core 2 and the ball bearings 5 and 6. The brackets 7 and 8 are formed by die-casting an aluminum alloy into a predetermined shape, and then immersed in a sulfuric acid solution and electrolytically oxidized using this as an anode, thereby forming black alumite 10 and 11 on their surfaces.

FIG. 2 shows an enlarged conceptual diagram of the black alumite-treated bracket surface. A black alumite 10 is formed on the outside of the aluminum alloy base metal 12,
This black alumite 10 has a sulfuric acid film 13 obtained by electrolysis in an aqueous sulfuric acid solution or the like. Since this sulfuric acid film 13 is porous, it has great heat collection and heat dissipation effects, and also has high corrosion resistance and abrasion resistance. In the deepest porous part of the sulfuric acid film 13, a precipitate 14 made of a metal or metal oxide that is colored black by secondary electrolysis in an electrolytic solution containing a metal salt or the like is deposited. The black metal or metal oxide precipitates 14 further enhance the heat collection and heat dissipation effects of the black alumite 10. By using the brackets 7 and 8 coated with black alumite 10 and 11 for the stepping motor 1, the heat generated inside the stepping motor 1 during use is efficiently transferred to the outside of the stepping motor 1 via the brackets 7 and 8. well released. Because heat collection and heat dissipation are carried out efficiently, even if the input current value for driving the motor is increased, the temperature rise due to the heat generated inside the motor is small, so the temperature is higher than that of a motor with the same structure. Current can be input and larger output can be obtained.

FIG. 3 shows a comparison of the temperature rise of a stepping motor subjected to black alumite treatment and a stepping motor not subjected to alumite treatment with respect to the input current value. As shown in Figure 3, the temperature of a stepping motor increases in proportion to the input current value, and the temperature of a stepping motor with an anodized bracket is higher than that of a stepping motor with a non-anodized bracket. Therefore, the temperature rise is small by about 8%. Furthermore, as is clear from FIG. 2, the black alumite 10, 11 is formed by oxidizing the surfaces of the brackets 7, 8 with a sulfuric acid solution, etc., so the surfaces of the brackets 7, 8 are not coated with a coating film as in the case of painting. It never bulges out. That is, the brackets 7 and 8 are coated with black alumite 10.
, 11, the stator core 2 and ball bearings 5 and 6 can be attached immediately. This makes it possible to omit steps such as polishing the inner surfaces of the brackets 7 and 8, and facilitates the manufacture of the brackets 7 and 8. Furthermore, since the black alumite 10, 11 has excellent corrosion resistance and wear resistance as described above, the stepping motor 1 can be used under severe conditions.

[0009]

[Effects of the Invention] As is clear from the above explanation, the stepping motor of the present invention has an excellent heat collection and heat dissipation effect because the surface of the bracket is coated with black alumite, and the rated capacity of the stepping motor can be increased. A larger, more efficient stepping motor can be obtained. Further, according to the present invention, the black alumite of the bracket has high corrosion resistance and wear resistance, so it is possible to obtain a stepping motor that can be used under severe conditions such as corrosion. Furthermore, in the stepping motor bracket of the present invention, precipitates made of metals and metal oxides are formed in the recesses of the anodic oxide film of the alumite through the coloring process.
The colored layer does not change the shape and dimensions of the bracket surface. With this, it is possible to omit operations such as polishing to remove the colored layer on the inner surface of the bracket after coloring, and it is possible to obtain a stepping motor that is easy to manufacture.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a stepping motor according to the present invention in the direction of the rotation axis.

FIG. 2 is an enlarged side sectional view showing black alumite of the bracket of the stepping motor of the present invention.

FIG. 3 is a graph showing a comparison of temperature rise due to input current between a stepping motor with a bracket coated with black alumite and a stepping motor without a bracket.

FIG. 4 is a cross-sectional view of a conventional stepping motor in the direction of its rotational axis.

[Explanation of symbols]

1 Stepping motor 2 Stator core 3 Rotor 4 Rotation axis 7 Bracket 8 Bracket 10 Black alumite 11 Black alumite

Claims (1)

[Claims] Claims: 1. A stepping motor having a bracket that rotatably supports a rotating shaft of a rotor and holds a stator in a predetermined position, wherein the surface of the bracket is coated with a black anodic oxide film. Features a stepping motor.