JPH09215234A - Rotor for stepping motor as well as cup used for this rotor and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotor, for a stepping motor, which is manufactured easily and which is low-cost. SOLUTION: Two cups 23, 23 are arranged and installed so as to be faced at the front and the rear of a shaft 19, and a magnet 21 is constructed on outer circumferential parts 26, 26 of the cups 23, 23. Hollow parts 27 are opened in external parts at bottom parts 24 of the cups 23, and barring parts 28 are formed at peripheral edges of the hollow parts 27 so as to compression-bond the shaft 19. In addition, round parts 25 are formed at corners between the bottom parts 24 and the outer circumferential parts 26 of the cups 23, and hollow parts 29, 29 are formed by the front end part and the rear end part on the inside face of the magnet 21. Then, an ultraviolet curing adhesive 30 is coated from the outer sides of the hollow parts 29, 29, and the cups 23, 23 are bonded to the magnet 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor for a permanent magnet type stepping motor.
The present invention relates to a rotor having a magnet bonded to the outer peripheral portion of the magnet holder.

[0002]

2. Description of the Related Art A conventional rotor of a stepping motor of this type will be described with reference to FIG. In the figure, reference numeral 1 denotes a rotor, a shaft 2 is arranged at the center of the rotor 1, and a magnet 3 is provided around the outer surface of the rotor 1. A magnet holder 4 is interposed between the shaft 2 and the magnet 3.

The magnet holder 4 is formed by cutting an aluminum rod into a bush shape with a lathe or boring machine, and the shaft press-fitting hole 5 is formed in the center.
Is opened, and the shaft 2 is press-fitted into the shaft press-fitting hole 5. Further, the outer peripheral portion of the bush-shaped magnet holder 4 and the inner side surface of the magnet 3 are adhered by a thermosetting adhesive 6.

[0004]

Since the magnet holder in the rotor of the conventional stepping motor of this type is formed by cutting an aluminum rod material into a bush shape by a lathe or boring machine, the processing cost is reduced. High, resulting in higher product prices. In particular, a large-diameter magnet holder having an outer diameter of more than 15 mm complicates the cutting work, so that the price increases accordingly.

Therefore, there arises a technical problem to be solved in order to facilitate the manufacture of this type of rotor and reduce the product price, and the present invention aims to solve the above problem.

[0006]

SUMMARY OF THE INVENTION The present invention has been proposed to solve the above problems, in which a shaft is crimped to the center of a magnet holder and a magnet is bonded to the outer periphery of the magnet holder. In the rotor of a stepping motor, the magnet holder is configured by disposing two cups each having a hollow disk-shaped bottom portion and a cylindrical outer peripheral portion protruding from the periphery of the bottom portion in front of and behind the shaft. Further, the present invention provides a rotor for a stepping motor in which the shaft is crimped to the hollow portion of the bottom portion, a burring is provided on the peripheral edge of the hollow portion, and magnets are installed and fixed on the outer peripheral portions of the front and rear cups. .

[0007] Also, by making the front and rear cups face each other,
The bottom portions of the front and rear cups are respectively directed to the front and rear outer sides of the rotor, and rounded portions are provided on the peripheral edges of the bottom portions so as to be bent toward the front and rear inner sides of the rotor. Further, the present invention provides a rotor for a stepping motor in which the cup and the magnet are adhered to each other by applying an adhesive to the recess formed between the outer surface of the rounded portion and the inner surface of the magnet.

Further, the present invention provides a stepping motor rotor using an ultraviolet curable adhesive as the adhesive. Furthermore, a rotor cup and a metal plate of a stepping motor having a hollow disk-shaped bottom peripheral edge overhanging a cylindrical outer peripheral portion through a rounded portion, and a burring formed on the bottom hollow peripheral edge are pressed by a press machine. The present invention provides a method for manufacturing the cup, which is punched and molded.

[0009]

FIG. 1 is a block diagram showing an embodiment of the present invention.
And FIG. In FIG. 1, reference numeral 11 denotes a stepping motor. An outer casing 12 of the stepping motor 11 is provided with a stator 13 around an inner surface thereof, and a rotor 14 is provided at the center thereof. The stator 13 winds the coil 15 around the bobbin 16 and
It is configured by fitting 6 into the yoke 17.

Bearings 18 are provided at the center of the front surface 12a and the center of the back surface 12b of the outer casing 12, and the shafts 19 of the rotor 14 are provided in these bearings 18, 18, respectively.
Are fitted and rotatably supported. Further, a magnet 21 is provided around the shaft 19 via a magnet holder 20 to form the rotor 14. A minute gap 22 is provided between the magnet 21 of the rotor 14 and the yoke 17 of the stator 13.

Thus, by exciting the coil 15 in a fixed pattern, the rotor 14 can be rotated by a predetermined angle. Thus, the magnet holder 20 is
The shaft 19 is composed of two cups 23, 23 arranged before and after the portion housed in the outer casing 12. As shown in FIG. 2, the cup 23 is formed by punching and molding a metal plate of iron, aluminum, brass or the like with a press machine. The outer peripheral portion 26 has a projecting shape. A hollow portion 27 is opened at the center of the bottom portion 24, and a burring portion 28 protruding in the same direction as the outer peripheral portion 26 is provided at the peripheral edge of the hollow portion 27.

Then, as shown in FIG. 1, if these two cups 23, 23 are made to face each other and the shaft 19 is press-fitted into the hollow portions 27, 27 of these two cups 23, 23, respectively.
23 and the shaft 19 are fitted and integrated. Further, at this time, since the burring portions 28, 28 are pressure-bonded to the peripheral side portion of the shaft 19, the connection is extremely strong and is not separated by load torque or the like.

Further, as described above, the two cups 23, 23 are
When they are opposed to each other in the front-rear direction, their bottoms 24, 24 are respectively directed to the front-rear outer sides of the rotor 14, and the outer peripheral portions 26,
26 will face each other at a constant interval. When the magnet 21 is installed on the front and rear outer peripheral portions 26, 26 facing each other in this manner, the front and rear end portions of the inner side surface of the magnet 21 and the rounded portions 25, 25 of the cups 23, 23.
With the outer side surface of the concave portion 29, 29 is formed.

Thus, when the UV curable adhesive 30 is applied to the recesses 29, 29 from the outside, the UV curable adhesive 30 is cured in about 1 minute, whereby the magnets 21 and 2 are cured. The rotor 14 is completed by bonding the cups 23, 23 to each other.

The present invention can be modified in various ways without departing from the spirit of the present invention, and it goes without saying that the present invention extends to such modifications.

[0016]

As described above, according to the present invention, the magnet holder is composed of two cups. Since the cups are punched and formed by the press machine, they can be formed on the lathe or the boring machine. It is possible to manufacture many pieces in a shorter time than the conventional bush-shaped magnet holder that is cut,
The processing cost can be reduced. In particular, the larger the magnet holder becomes, the more difficult the machining becomes, and the price becomes much lower than that of the bush magnet holder having the same diameter.

Further, since the burring is provided on the periphery of the hollow portion of the cup, the burring can be pressure-bonded to the peripheral side portion of the shaft to strengthen the coupling between the cup and the shaft. Further, the burring and the rounded portion at the periphery of the bottom of the cup can be easily formed by press molding.

When the front and rear cups are opposed to each other, the outer surface of the rounded portion of the cup and the front and rear end portions of the inner surface of the magnet form a recess, so that the recess is formed. If the adhesive is applied from the front and rear outside of the rotor to the cup and the magnet, it is possible to apply the adhesive to the entire outer surface of the cup outer peripheral portion and the entire portion of the inner surface of the magnet that abuts the outer surface of the cup outer peripheral portion. Can be glued. Therefore, the bonding work becomes extremely simple.

Further, when the bonding work is performed by using an ultraviolet curable adhesive as in the third aspect of the invention, the ultraviolet curable adhesive is cured in a short time of about 1 minute, It is not necessary to batch the bonding process as in the case of using a conventional thermosetting adhesive, and the entire rotor assembly process can be lined up. Thus, the rotor can be efficiently manufactured, and the product price can be reduced as much as possible.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional side view of a stepping motor incorporating a rotor according to the present invention.

FIG. 2 is a perspective view of the cup in FIG.

FIG. 3 is a sectional view showing a conventional example.

[Explanation of symbols]

 11 Stepping Motor 14 Rotor 19 Shaft 20 Magnet Holder 21 Magnet 23 Cup 24 Bottom 25 Rounded Part 26 Peripheral Part 27 Hollow Part 28 Burring Part 29 Dimple 30 UV Curing Adhesive

Claims (5)

[Claims] 1. In a rotor of a stepping motor in which a shaft is pressure-bonded to a central portion of a magnet holder and a magnet is adhered to an outer peripheral portion of the magnet holder, the rotor is extended from a hollow disc-shaped bottom portion and a peripheral edge of the bottom portion. The magnet holder is constructed by arranging two cups consisting of a cylindrical outer peripheral portion in front of and behind the shaft, and a burring is formed on the peripheral edge of the hollow portion of the bottom portion to crimp the shaft. Further, a rotor for a stepping motor characterized in that magnets are installed and fixed on the outer peripheral portions of the front and rear cups. 2. The front and rear cups are opposed to each other, and the bottom portions of the front and rear cups are respectively directed to the front and rear outer sides of the rotor,
A rounded portion that bends inward and rearward of the rotor is provided on the peripheral edge of the bottom portion, the bottom portion of the cup and the outer peripheral portion are connected via the rounded portion, and the outer surface of the rounded portion and the inner surface of the magnet are further connected. The rotor for a stepping motor according to claim 1, wherein the cup and the magnet are adhered to each other by applying an adhesive to the formed recess. 3. The stepping motor rotor according to claim 2, wherein the adhesive is ultraviolet curable. 4. A rotor cup for a stepping motor having a hollow disk-shaped bottom peripheral edge overhanging a cylindrical outer peripheral portion through a rounded portion, and a burring formed on the bottom hollow peripheral edge. 5. The method for manufacturing a cup according to claim 4, wherein the metal plate is punched and molded by a press machine.