JPH08228451A - Small motor - Google Patents

Abstract

PURPOSE: To maintain output and reduce process by providing an opposite plane wall portion and curved wall portion for the side wall of a cylindrical stator frame with bottom formed by drawing sheet metal, forming the plane wall portion and the bottom with small radii of curvature and arranging a pair of permanent magnets at the inner side of the curved wall portion. CONSTITUTION: A stator frame 10 has a bottomed cylindrical shape by drawing sheet metal and is equipped with plane wall portions 20 parallel each other, facing curved surface wall portions 22, a bottom 24 and edge portions 26 and 28. The plane wall portions 20 and the bottom 24 are connected by the edge portion 26, and the edge portion 26 has a small radius of curvature at the central portion but it becomes larger as it becomes far from the central portion. The curved wall portion 22 and the bottom 24 are connected by the edge portion 28, and the edge portion 28 has the radius of curvature same as the end portion of the edge portion 26. A magnet 12 comprises a permanent magnet having an outer surface equal to the curved surface of the curved surface wall portion 22, and a fixed spring 14 is a rod-shaped spring which presses the magnet 12 to the stator frame 10 and comprises two straight portions 30 and a bent portion 32. By doing this, manufacturing process can be reduced while maintaining the output characteristics and also the cost can be lowered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small motor, and more particularly to a small motor characterized by the shape of a stator frame.

[0002]

2. Description of the Related Art A stator for a small motor, particularly a stator for a small direct current motor using a magnet (permanent magnet) as a field pole, has a stator frame 100, as shown in FIG. The magnet 12, the fixed spring 14, and the bearing 16 are provided.

Here, as shown in FIG. 4, the stator frame 100 is formed into a cylindrical shape with a bottom by drawing a sheet metal, and has a flat side wall 120 facing each other and a curved side wall 12 facing each other.
2, having a bottom 124 and an edge 110 connecting them gently. Further, the stator frame 100 is provided with a bearing 16 at the center of the bottom portion 124.

Next, the magnet 12 comes into contact with and fits inside the curved side wall 122 of the stator frame 100.

Further, the fixed spring 14 is a bar-shaped spring having two straight portions 30 and a bent portion 32 connecting them. The fixed spring 14 is elastically deformed into a U shape and is inserted into the stator frame 100 so that the two parallel straight portions 30 are in contact with both magnets 12, 12 while being in contact with the inside of the plane side wall 120. It is located in.

With the above-described structure, in the stator of the small motor, the straight portion 30 of the fixed spring 12 causes the magnet 12 to move to the curved side wall 122 of the stator frame 10 by the elastic force of the fixed springs 14 and 14 trying to spread. The structure is such that it is pressed down and fixed inside.

A rotor (not shown) is inserted into the stator frame 100, and a rotary motion is performed in a space between the two magnets 12. The rotor movable area 18 is
The movable space area of the rotor due to this rotational movement is shown. That is, the rotor has a space area sandwiched between two magnets 12 and two fixed springs 14 arranged in parallel.
A rotary movement is performed in a space area between the two straight portions 30, 30.

By the way, since the fixed spring 14 is provided with the bent portions 32 connecting the straight portions 30 in addition to the straight portions 30, if the fixed spring 14 is not properly mounted, the bent portions 32 interfere with the rotor. Will be lost.

Therefore, the fixed spring 14 must be mounted so that the bent portion 32 is located deeper than the rotor movable region 18, and the fixed spring 14 has the apex of the bent portion 32 at the stator. It must be inserted as far as it contacts the bottom 124 of the frame 100.

Further, the bent portion 32 of the fixed spring 14
In order to allow the apex of the blade to contact the bottom portion 124 of the stator frame 100, the edge portion 110 of the bottom portion 124 of the stator frame 100 is machined with a small radius of curvature similar to the diameter of the rod-shaped fixed spring 14. Must have been

For the above reason, the stator frame 10 has been conventionally used.
The bottom portion 124 of 0 had the edge portion 110 rounded with a small radius of curvature in the sheet metal drawing process.

However, the stator frame of a small motor generally has a deeper bottom than its diameter, and redrawing is necessary in the drawing process in order to give a small radius of curvature to the edge portion 110 of the bottom portion 124. Therefore, the manufacturing of the stator frame 100 requires a plurality of steps, which causes a problem of increasing the manufacturing cost of the small motor.

It should be noted that changing the configuration of the rotor and the magnet 12 is an irrational change. That is, when the positional relationship between the rotor and the magnet is deviated, a large magnetic attraction force is exerted and the output of the motor is reduced. Also, when the diameter of the rotor is reduced, the magnetic flux also decreases and the output of the motor decreases. That is, in order to eliminate the inconvenience of the manufacturing process of the stator frame 100 while maintaining the output characteristics of the motor, the configuration other than the stator frame 100 should not be changed, and only the shape of the stator frame 100 should be changed. Need to be changed.

As an example of this modification, the stator frame 100
It is conceivable to machine the edge portion 110 of the bottom portion 124 with a large radius of curvature as a whole. However, the stator frame 10
If this change is performed without changing the configuration other than 0, the side wall portion of the stator frame 100 must be extended, that is, the cylindrical stator frame 100 must be deepened. This violates the demand for miniaturization that the small motor originally has.

The present invention has been made in view of the above problems, and an object thereof is to provide a stator frame shape of a small motor capable of reducing the steps required for forming the motor while maintaining the motor configuration and output characteristics. To do.

[0016]

In order to achieve the above-mentioned object, the invention according to claim 1 has a bottomed cylindrical stator frame formed by drawing a metal plate in a small motor. The side wall of the stator frame has a flat surface wall portion and a curved surface wall portion that face each other, and has a flat shape in which the facing portion of the cylinder is crushed, and only the central portion of the connecting portion between the flat wall portion and the bottom portion is formed. Formed with a small radius of curvature, a pair of permanent magnets are arranged inside each curved wall portion, and a U-shaped elastically deformed rod-shaped spring is arranged inside the plane wall portion, and the rod-shaped springs are supposed to spread. The pair of permanent magnets are pressed against and held by the curved wall portion by the elastic force of, and the bent portion of the rod-shaped spring is brought into contact with the inside of the central portion of the connection portion having a small radius of curvature so that the rod-shaped spring is It is characterized by being attached.

[0017]

According to the small motor having the above structure, both permanent magnets forming the field pole are housed inside the curved side wall of the stator frame so as to be in contact with the curved surface, and the rod spring is elastically deformed into a U shape. Meanwhile, the apex of the bent portion is inserted so as to come into contact with the edge portion of the bottom portion rounded off with a small radius of curvature of the stator frame.

In the small motor thus formed, the edge portion 1 of the bottom portion 124 of the conventional stator frame 100 is used.
The configuration is such that only the shape of 10 is changed (see FIG. 3).

That is, according to the present invention, inside the stator frame, only the edge of the portion where the bent portion of the rod-shaped spring abuts has a shape rounded with a small radius of curvature, and the structure other than the stator frame is used. Is as usual. Therefore, while maintaining the output characteristics of the motor, it is possible to reduce one or more steps of redrawing, which is conventionally required when forming the stator by drawing the sheet metal.

[0020]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 2 is a three-view drawing showing the stator of the small motor according to this embodiment, and FIG. 1 is a perspective view showing the stator frame.

As shown in FIG. 2, the small motor of this embodiment comprises a stator frame 10, a magnet 12, a fixed spring 14, and a bearing 16.

The stator frame 10 is an outer frame for forming the small motor of this embodiment, and is formed into a cylindrical shape with a bottom by drawing a sheet metal, and as shown in FIG. 1, flat surfaces parallel to each other. Wall portions 20, 20 and curved surface wall portions 22, 22 facing each other
And has a bottom 24 and edges 26, 28.

Here, the flat wall portion 20 and the bottom portion 24 are connected by an edge portion 26, which has a small radius of curvature at its central portion and has a larger radius of curvature as the distance from the central portion increases. Has the shape of having.

On the other hand, the curved wall portion 22 and the bottom portion 24 have the edge portion 2
8 and the edge 28 is connected to the edge 26.
The shape has the same large radius of curvature as the end part of. That is, the edge portion 28 is rounded with a relatively large constant radius of curvature.

Next, the magnet 12 constitutes the field pole of the small-sized motor of this embodiment, and a plate-shaped permanent magnet is used as a surface having the same shape as the curved surface of the curved wall portion 22. Make a curved shape to have as.

Next, the fixed spring 14 is a bar-shaped spring for pressing and fixing the magnet 12 to the stator frame 10 in the small motor of this embodiment.
It is composed of one straight line portion 30 and a bent portion 32 connecting them.

Further, the bearing 16 is for inserting and supporting the shaft (not shown) of the rotor of the small motor of this embodiment, and is provided at the center of the bottom portion 24 of the stator frame 10. .

As described above, in the shape of the stator frame 10 of the present small motor, only the central portion of the edge portion 26 of the edge portions 26, 28 has the bottom portion 124 of the conventional small motor stator frame 100. It has a small radius of curvature similar to the edge 110 (see FIG. 3), and the other edges have a relatively large radius of curvature. That is, in the stator frame 10 in the small-sized motor of the present embodiment, the flat side wall 20, the curved side wall 22, and the bottom portion 24 are connected with a gentler curved surface than in the case of the conventional stator frame 100. Make a shape.

Therefore, when forming the stator frame 10 by drawing a sheet metal, the conventional stator frame 100 is used.
It is possible to reduce the number of steps by one or more as compared with the number of steps when forming is performed by sheet metal processing.

In order to form the stator of the present small motor, for example, two magnets 12 are first inserted inside the curved side wall 22 of the stator frame 10 so that the outer surfaces of the magnets 12 are in contact with each other. , Hold it down.

Next, the fixing spring 14 is attached to the stator frame 1
The bent portion 32 of the fixed spring 14 is in contact with the inside of the flat side wall 20 of 0, and the bottom portion 2 of the stator frame 10 is
4 is inserted while elastically deforming in a U shape so as to come into contact with the central portion of the edge portion 26 of No. 4, that is, the edge portion having the smallest radius of curvature.

In the stator of this small-sized motor thus formed, the U-shaped fixed spring 12 is generated by the elastic force of the fixed springs 14 and 14 to spread.
The linear portion 30 presses the magnet 12 inside the curved side wall 22 of the stator frame 10 to fix the magnet 12.

In the small motor according to the present embodiment, a rotor (not shown) rotates in the movable area 18. That is, the rotor rotates in the space area sandwiched between the two magnets 12 and in the space area between the two linear portions 30 of the fixed spring 14.

Here, the fixed spring 14 is inserted up to the bottom portion 24 of the stator frame 10 as in the case of the conventional small motor, and the bent portion 32 is arranged so as not to enter the movable region 18 of the rotor. .

That is, the small motor according to this embodiment has the same magnet 12, the same fixed spring 14, the same bearing 16 and the same diameter and the same as the conventional stator frame 100 as the conventional small motor. It has a stator frame 10 with a depth of.

As described above, the small-sized motor of this embodiment has the bent portion 3 of the fixed spring 14 inside the stator frame 10.
Only the central portion of the edge portion 26 with which the 2 abuts has a shape rounded with a small radius of curvature, and the configuration other than the stator frame 10 is the same as the conventional one. That is, in this embodiment, by changing only the shape of the edge portion 110 of the bottom portion 124 of the conventional stator frame 100, while exhibiting the same configuration and output characteristics as the conventional motor, the manufacturing process of the stator frame is performed. This has the advantage of reducing one or more steps.

[0038]

As described above, according to the small motor of the present invention, the drawing process is performed when the stator frame is formed while maintaining the structure and output characteristics of the conventional small motor. Since the number of steps can be reduced by one or more, the manufacturing cost can be reduced.

[0039]

[Brief description of drawings]

FIG. 1 is a perspective view showing a stator frame of a small-sized motor according to the present invention.

2A and 2B are views showing a stator in a small-sized motor of the present invention, where FIG. 2A is a front view of the bottom of an opening of a stator frame, FIG. 2B is a side view thereof, and FIG. It is a figure.

3A and 3B are diagrams showing a stator in a conventional small-sized motor, in which FIG. 3A is a front view of a bottom of an opening of a stator frame, FIG. 3B is a side view thereof, and FIG. Is.

FIG. 4 is a perspective view showing a stator frame of a conventional small-sized motor.

[Explanation of symbols]

 10 Stator frame of small motor of the present invention 12 Magnet 14 Fixed spring 20 Planar wall part 22 Curved wall part 24 Bottom part 26 Edge part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ishikawa ▲ Toshi ▼ Man 390 Umeda, Kosai City, Shizuoka Prefecture Asmo Stock Company In-house

Claims (1)

[Claims] 1. A small motor, comprising a bottomed cylindrical stator frame formed by drawing a metal plate, wherein the side walls of the stator frame have flat wall portions facing each other and curved wall portions facing each other. Having a flat shape obtained by crushing the opposing portion of the cylinder, only the central portion of the connecting portion between the flat wall portion and the bottom portion is formed with a small radius of curvature, and a pair of permanent magnets inside the curved wall portions. Arranged, a bar-shaped spring elastically deformed in a U-shape is arranged inside the plane wall part, and the pair of permanent magnets are pressed against the curved wall part by the elastic force of the bar-shaped spring trying to spread and held, A small motor, characterized in that the rod-shaped spring is attached by abutting the bent portion of the rod-shaped spring inside the central portion of the connecting portion having a small radius of curvature.