JPS61135356A - Miniature motor - Google Patents

Abstract

PURPOSE:To enhance the precision of torque and stepping, by punching a magnetic plate to form a plurality of pole teeth integrally, and by forming the punched plate in a cylindrical shape to form a stator side pole tooth unit. CONSTITUTION:A miniature motor having stator side pole tooth units 4 in a cup-formed case and a plate-formed case, is formed with the rotor of a permanent magnet supported to be freely rotated by the bearing of the cases. The pole tooth units 4 are formed in a cylindrical shape to surround the rotor, and a plurality of pole teeth 4a-4d and projections 10 fitted on slots for positioning the cases are integrally formed. And a core 13, a coil and a bobbin 15 are put together on the outer periphery of the pole tooth units 4, and are fitted in a magnetic combining state. The pole tooth units 4 are formed by punching a magnetic plate 20, and the punched plate is formed in a cylindrical shape in a curling process. Then, the pole tooth units 4 are formed in an exactly cylindrical shape, and the shape between the units and the rotor is arranged to be even, and torque is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a small electric motor, and particularly to the structure of a pole tooth body on the stator side thereof.

BACKGROUND OF THE INVENTION Small electric motors of this type, such as stamping motors or synchronous motors, are equipped with a permanent magnet rotor and a large number of pole teeth along its corresponding circumferential surface. These pole teeth are provided on the inner circumferential surface of an annular case or an annular core, as in, for example, JP-A-58-112053 or JP-A-55-29214, and are suitable for punching and bending of magnetic materials. Formed by processing. For this reason, the accuracy of the assembly of each part in the completed state of a small electric motor is directly dependent on the accuracy of the press punching process, especially the bending process. As a result, there are the following drawbacks.

First of all, in press bending, it is difficult to perform processing with high precision, so the distance between the permanent magnet rotor and the pole teeth, that is, the air gap in the circumferential direction, cannot be made small, so the motor torque is You will be limited by that.

Second, when the pole teeth are formed by bending, the gaps between adjacent pole teeth are not uniform in the circumferential direction due to variations in the bending parts, which results in poor rotor stepping accuracy and There is uneven rotation.

Third, when bending a magnetic material, work hardening occurs in the material itself and the magnetic permeability of the material decreases, so an annealing process is required as a countermeasure. For this reason, heat processing becomes essential, which complicates the production process and increases product prices. As described above, in conventional small electric motors, since bending is always required in the manufacturing process of the pole teeth, there remain problems in rotor torque, step accuracy, uneven rotation, and manufacturing.

OBJECTS OF THE INVENTION Accordingly, an object of the present invention is to improve the torque of this type of small electric motor by eliminating the drawbacks of the prior art, that is, the bending of the pole tooth portions, and to increase the stepping accuracy, as well as to improve the stator, especially its poles. The purpose is to simplify the manufacturing of the tooth part.

SUMMARY OF THE INVENTION Therefore, the present invention has been devised to form a plurality of pole teeth integrally by punching a flat magnetic material, and to form a cylindrical shape to form a pole tooth body on the stator side. I have to.

These pole teeth have already been precisely formed in predetermined positions by the punching process of the flat magnetic material, and remain in a positional relationship that does not shift even after being connected in a cylindrical shape. Therefore, the mutual spacing between these pole teeth can be ensured with high accuracy.

When the punched magnetic bodies are connected in an annular shape, their inner circumferential surfaces face the outer circumferential surface of the rotor, but the curling of the pole teeth does not result in local bending as in conventional methods. In comparison, since this can be done with high precision, the gap between the outer circumferential surface of the rotor and the inner circumferential surface of these pole teeth can be made as small as possible. Therefore, the torque of the completed small electric motor will be sufficiently higher than that of a conventional motor with a similar structure.

In addition, since these pole teeth are on almost the same plane as the original flat magnetic material and cannot be locally bent like in the past, there is no reduction in magnetic permeability due to work hardening, etc. Magnetic properties are fully utilized. 2 Configuration of Embodiment Hereinafter, the configuration of an embodiment of the present invention will be specifically described based on the drawings.

First, FIGS. 1 and 2 show an assembled state of a small electric motor 1 according to the present invention. This small electric motor 1 includes a main part of the present invention, that is, a stator-side pole tooth body 4 inside a cup-shaped case 2 and a flat plate-shaped case 3. These cases 2.3 also have bearings 5.6 fixed at their respective center positions, which rotatably support the shaft 8 of the rotor 7 made of permanent magnets (isotropic ferrite). Note that the rotor 7 of this example is
It is a cylindrical body and is supported by an internal support body 19.

As seen in FIGS. 3 and 4, the pole tooth body 4 is configured as a cylindrical body surrounding the rotor 7, and has a plurality of pole teeth 4a, 4b extending in the axial direction of the shaft 8.
4c and 4d are formed alternately along the circumferential direction, and protrusions 10 that fit into the positioning holes 9 of the case 2.3 are integrally formed at both end edges. These pole teeth 4a,
4b, 4c, and 4d are formed into trapezoidal shapes with zigzag gaps 11 to obtain a spatially ideal magnetic flux distribution, as shown in FIG. In this embodiment, the pole teeth 4a and 4b form a pair, and the other pole teeth 4c and 4d form a pair, and the pole teeth 4b and 4c are integrally formed at the base portion. , they are connected by a connecting part 12. The connecting portion 12 is formed with a narrow width as shown in FIG. 6 so as to be magnetically saturated, but if necessary, it may be made thinner by necking as shown in FIG. .

A core 13, a coil 14, and a bobbin 15 are combined around the outer periphery of the pole tooth body 4. The core 13 is made of the same magnetic material as the pole tooth body 4, and has a ring shape or a split ring shape, and its inner peripheral portion forms a convex angle with the outer peripheral surface of the pole tooth body 4. while being magnetically coupled.

At this time, the inner circumferential surface of the core 13 is closely joined to the substantially central portion of the pole tooth body 4 in order to suppress magnetic resistance. The pole tooth body 4 and the core 13 together with the case 2.3 form a magnetic path for the magnetic flux caused by each coil 14. The excitation coil 14 is formed around the outer periphery of the pole tooth body 4 and the core 3, and is wound inside the two bobbins 15. This bobbin 15 is integrally molded by plastic insert molding after combining the core 13 with the outer periphery of the cylindrical pole gear body 4, with the core 13 sandwiched therebetween. During this molding, a portion of the winding drum 15a of the bobbin 15 enters into the gap 11 as shown in FIG. 8, and acts as a spacer to regulate the distance therebetween. Further, one flange 15b of the bobbin 15 is thicker (molded) than the other flange 15b, and the terminals 16a, 16b, and 1 of the coil 14 are formed at that portion.
6c is fixed by embedding. These terminals 16
a, 16b, and 16C are connected to the lead wire 17,
It is guided to the outside through an insulating bush 18 attached to the boundary between the cases 2 and 3. Here, along the circumference of the winding drum 15a and along the inner circumferential surface of at least one flange 15b, a strain absorbing material is provided. lIl
5c is integrally formed.

Manufacturing Process of Pole Tooth Body Here, the manufacturing process of the above-mentioned pole tooth body 4 will be specifically explained.

The pole tooth body 4, which is the main part of the present invention, is formed by punching out a flat magnetic material 20, as shown in FIG. In this punching process, for example, a strip-shaped magnetic material 20 is continuously supplied, and then diagonal cutting lines 22 are cut every predetermined length.
This can be done automatically by cutting at the position. In this manufacturing process, the pole teeth 4a, 4b, 4c, and 4d are formed simultaneously with the teno gear/branch 11 as a removal allowance.

Next, this flat plate-shaped pole tooth body 4 is formed into a cylindrical shape by the next curling process, but in preparation for this, the pole teeth 4b, 4c
A locking hole 21 for curling is integrally formed along the boundary, that is, along the longitudinal direction. Also, the cutting line 22 is
It is formed obliquely along the longitudinal direction of the magnetic material 20,
This is effective in expanding the connection part with the other end in the circumferential direction, eliminating sudden changes in magnetic properties on the circumference, and preventing steps during curling.

Next, the flat plate-shaped pole tooth body 4 is formed into a cylindrical shape in the next curling process, as shown in FIGS. 3 and 4.
It is fitted inside the core °13.

During this curling process, the pole teeth 4 as 4 bs 4
Since the portion where 0%4d does not exist, that is, the narrow width portion, is easily deformed, the pole tooth body 4 tends to have a polygonal shape when viewed from the open end. Therefore, as shown in FIG. 9, each pole tooth 4a, 4b,
If the portions 4c and 4d are previously bent to have a curvature equal to the curvature of the cylindrical pole tooth body 4, the pole tooth body 4 after the curling process will have an accurate cylindrical shape. This curved surface processing is performed using magnetic material 20.
This can be done at the same time during the punching process. As a result, the gap between the pole tooth body 4 and the rotor 7 becomes uniform, and the opposing area between them increases, so that the torque of the rotor 7 is increased as much as possible.

At this stage of curling, each pole tooth 4a
, 4b, and 4C14d becomes unstable, a plastic layer 23 is formed on the surface of the flat plate-shaped pole tooth body 4 by insert molding or the like. As shown in FIGS. 10 and 11, this plastic layer 23 covers the outer circumferential surface of the pole tooth body 4 except for the portion to be joined to the core 13, and enters into the gap 11 to connect them to each other. In addition to regulating the positional relationship, it is also used for insulation protection of the coil 14 afterwards.

Further, as shown in FIGS. 12 and 13, this plastic layer 23 is made by cutting the front or back surfaces or both sides of the pole teeth 4a, 4b, and 4C14d along the width thereof to reduce their thickness. Alternatively, a plastic filling may be formed in the thinned portion. In this way, the plastic layer 23 that has entered the inside of the gap 11
Even after the pole tooth body 4 is formed into a cylindrical shape, a part of the pole tooth body 4 does not protrude from the inside of the gap 11 and remains within the gap 11. Further, the above-mentioned thin portion may be formed in a zigzag shape along the gap 11. Plastic layer 2 like this
3 is effective for ensuring the necessary gap 11 of the pole tooth body 4 even after the curling process.

Note that this plastic layer 23 can also be replaced with a nonmagnetic material, such as a thin copper plate. In this case, the copper plate becomes the outer periphery of the flat plate-shaped pole tooth body 4. It is attached to the surface by fixing means such as spot welding. At this time,
Unlike the plastic layer 23, the inside of the gap 11 is a space.

After the curling process, the cylindrical pole tooth body 4 has a perfect circular shape, and has a predetermined phase shift on the circumference to form a gap 11. In this state, when the connecting portion 12 is separated as necessary, the magnetic flux is transferred to the pole tooth 4.
Since it becomes easier to flow from a, 4b, 4c, and 4d to the rotor 7, the magnetic properties of the pole tooth body 4 are further improved. In addition, in the case of this cutting, the plastic layer 23 is formed thinly at the connecting portion 12.

As already mentioned, the core 13 is configured as a single annular body or a split annular body, and is fixed in a state of magnetic coupling almost at right angles to the cylindrical pole tooth body 4 after curling. .

In FIG. 14, the center pole teeth 4b, 4c are formed into a cylindrical shape and integrally formed with the core 13 and bobbin 15 using the method already described, and then the outer pole teeth 4a, 4d are formed on the left and right open ends. An example of fixing by press-fitting is shown. In such an assembly process, the gap 11 tends to become non-uniform, so a protrusion corresponding to the gap 11 is formed on the inner peripheral surface of the bobbin 15. As a result, the pole teeth 4a,
Even if 4d is combined, the necessary gap 11 can be secured.

Winding Process Next, the process of winding the coil 14 around the two bobbins 15 will be explained.

The terminal 16 is connected to one bobbin 15 as shown in FIG.
There are three of them, embedded in the thick flange circumferentially. And these are two bobbins 1
5, they are formed on the left and right sides of the center line in the generatrix direction, and their pitches are the same.

In the case of a unipolar drive system, during zero winding, which is bifilar winding, the bobbin 15 is integrated with the pole gear body 4 and the core 13, as shown in FIG. It is fixed to a support shaft 26 on the center of rotation.

This flyer 24 for winding is attached to each bobbin 15.
By pulling out two electric wires 25 at each time, and by rotational movement,
These electric wires 25 are wound around the winding drum 15a of the bobbin 15. At this time, one end of the two electric wires 25 is connected to the terminal 16.
After being attached to parts b and 16c, they are fixed by soldering or the like. When the required number of turns has been completed, the wire 25 connected to the terminal 16b is connected to the terminal 16a, and the wire 25 connected to the terminal 16c is connected to the common terminal 16b with similar fixing means at its other end. Connected with Therefore, in the completed state of this small electric motor 1, the user should use the terminal 16b in common and use the other terminals 16a or 1
By selecting one of 6c, the rotational direction of the rotor 7 can be set to any direction.

The winding fryer 24 is also movable in the axial direction, and automatically ties the electric wires 25 to the terminals 16a, 16b, 16C by moving in the axial direction and swinging motion in the rotational direction. go. Thereafter, the aforementioned lead wire 17 is connected to these terminals 16a116b, 16c by means such as soldering. Note that these lead wires 17
can also serve as terminals 16a, 16b, and 16c at their ends.

In the process of winding the electric wire 25 in this manner, the flange 15b is deformed in the opening direction due to the lateral force of the electric wire 25, and the position of the pole teeth 4a, 4b, 4c is shifted due to the distortion. As a result, it is also predicted that the distance between the gaps 11 will change. As a countermeasure against this, as already described, the groove 15c is formed in the outer circumferential portion of the winding drum 15a or the outer inner circumferential portion of the flange 15b. This groove 15c is for the electric wire 25
When the winding is thickened, the external force is absorbed and acts not to act on the pole tooth body 4.

Modifications of the Invention The above embodiment has four pole teeth 4 corresponding to two coils 14.
A, 4b, 4c, and 4d form a pole tooth body 4. However, in the present invention, the pole tooth body 4 has two pole teeth 4a, 4b,
Alternatively, in addition to the case of only the pole teeth 4c and 4d, it also includes the case of only the central pole teeth 4b and 4c. The pole tooth body 4 is the pole tooth 4a
, 4b, or the pole teeth 4c, 4d, the effect of the invention is sought in that the gap 11 between them is formed with high accuracy. Further, when the pole tooth body 4 is constituted by continuous pole teeth 4b, 4C, it is advantageous in that the mutual positional relationship of the pole teeth 4b, 4C can be precisely regulated.

Effect of the invention The present invention provides the following unique effects.

First, since the cylindrical pole tooth body forms the pole teeth in the same plane as the flat magnetic body before punching, there is no need to bend the pole teeth in the right angle direction during the manufacturing process. The mutual positional relationship between the two and the positional relationship of the gaps can be precisely regulated.

In addition, in the punching process during the forming process of the pole tooth body, compared to bending process, the mold can ensure higher precision, so the accuracy of the pole teeth after manufacturing is better, and therefore the characteristics of small electric motors, especially stepping When using a motor, the step accuracy is increased, and when using a synchronous motor, rotational unevenness is reduced.

Further, although curling is performed in the manufacturing process of this pole tooth body, the magnetic material is not bent by 90 degrees in this curling process, and thus does not adversely affect the processing accuracy. In addition, the magnetic permeability is reduced, and the characteristics of the magnetic material can be effectively utilized.

[Brief explanation of drawings]

Fig. 1 is a side view of the small electric motor of the present invention, Fig. 4 is a sectional view thereof, Fig. 3 is a front view of the pole tooth portion on the stator side, and Fig.
The figure is a sectional view, FIG. 5 is a plan view of a part of the pole tooth body in an expanded state, FIG. 6 is an enlarged front view of the connecting portion, FIG. 7 is an enlarged sectional view of the connecting portion, and FIG. An enlarged cross-sectional view of the bobbin, FIG. 9 is a front view showing the state of bending of the pole tooth body, FIG. 10 is a plan view of a part of the pole tooth body in another embodiment, and FIG. 11 is FIG. 12 is a plan view of a part of the pole tooth body of another embodiment, FIG. 13 is a sectional view of the structure shown in FIG. 12,
Fig. 14 is a partial cross-sectional view showing another example when the pole teeth are combined, Fig. 15 is a plan view showing the starting state of winding the electric wire, and Fig. 16 is a side view showing the winding process of the electric wire. It is a diagram. ■...Small electric motor, 2...Case, 3...Case, 4...
・Pole tooth body, 7.. Rotor, 11.. Gap, 12.
- Connecting portion, 13... Core, 14... Coil, 15... Bobbin, 20... Magnetic material, 23... Plastic layer. Patent applicant: Sankyo Seiki Seisakusho Co., Ltd. Figure 1
Figure 2 Figure 9 Figure 70 Figure 17 Procedural amendment (voluntary) 1. Indication of the case 1982 Patent Application No. 256179 2. Name of the invention Small electric motor 3. Person making the amendment Relationship to the case Patent Applicant Address 5329 Shimosuwa-cho, Suwa-gun, Nagano Prefecture Name
(223”) Sankyo Seiki Co., Ltd. Representative Yama 1
) 6-4, Agent Lu 160 Address: No. 708, Shinjuku Seven Building, 2-8-1 Shinjuku, Shinjuku-ku, Tokyo 6, Scope of Claims and Detailed Description of the Invention column 7 of the specification to be amended , the contents of the amendment (11. The scope of claims in the Clarification Statement is corrected as shown in the attached sheet. (3) Delete "even after being connected in a cylindrical shape" in line 15 of page 3 of the specification. (4) Line 6 of page 15 of the specification ``Cylindrical'' is deleted. 2. Claims 2. A li-body top plate punched from a flat magnetic material and integrally formed with a plurality of alternately protruding pole teeth. A small electric motor characterized by its simple design and design.

Claims (1)

[Claims] A small electric motor characterized by comprising a cylindrical pole tooth body punched from a flat magnetic material and integrally formed with a plurality of alternately protruding pole teeth.