JP4442032B2 - Stepping motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to the structure of a stepping motor mainly used for information-related equipment.
[0002]
[Prior art]
In recent years, in information-related equipment, stepping motors (hereinafter referred to as motors) having higher reliability have been demanded.
[0003]
The motor is required to have high reliability as well as high productivity. FIG. 5 shows the structure of a conventional motor. Reference numeral 6 denotes a stator including a coil 7 and a comb-shaped yoke 8. Reference numeral 9 denotes an oil-impregnated metal bearing. Reference numeral 10 denotes a sliding washer. Reference numeral 111 denotes a substantially cylindrical magnet 1 which is multipolarly magnetized in the circumferential direction. It is a rotor having. Conventionally, a rotor described in Japanese Patent Application No. 11-132268 is known as a rotor of a motor.
[0004]
FIG. 4 shows a method for manufacturing the rotor 111 used in the conventional motor. In FIG. 4, reference numeral 1 is a substantially cylindrical magnet that is multipolarly magnetized in the circumferential direction, 2 is a shaft arranged coaxially with the magnet, and 31 is heat that couples the shaft 2 and the magnet 1. It is a molded member made of a curable resin. The rotor of the motor is completed by inserting the shaft 2 and the magnet 1 into the molding die 4 and injecting and curing a molding member 31 made of a thermosetting resin.
[0005]
[Problems to be solved by the invention]
In the rotor described above, a molding member 31 made of a thermosetting resin is injected and cured. Since the thermosetting resin has good flowability during molding and a small shrinkage rate, a highly accurate motor rotor can be obtained. However, on the other hand, there is a problem that burrs are liable to enter into a minute gap. In particular, if burrs adhere to the gap between the shaft and the molding die, it is difficult to remove the rotor from the molding die, and at the same time, burrs remain attached to the molding die or the shaft after the rotor is removed. If burrs remain attached to the shaft, it will enter the sliding part of the bearing and reduce the motor life. If burrs remain attached to the molding die, it is difficult to insert the shaft into the molding die. was there.
[0006]
The present invention solves such a conventional problem, and provides a motor having a rotor with high reliability and good productivity while suppressing the occurrence of burrs in the gap between the shaft and the molding die. Objective.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention is one in which a shaft in which a heat-resistant thin plate material is press-fitted in advance to the position of the end face of the molded member before integral molding is integrally molded with a thermosetting resin.
[0008]
As a result, the gap between the molding die and the shaft can be closed with the heat-resistant thin plate material, and the problem that the thermosetting resin enters the gap between the shaft and the die to generate burrs can be solved.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
According to a first aspect of the present invention, there is provided a magnet having a substantially cylindrical shape and being multipolarly magnetized in a circumferential direction, a shaft disposed coaxially with the magnet, the shaft and the magnet. A method of manufacturing a stepping motor having a rotor comprising: a molding member made of thermosetting resin to be coupled; and a heat-resistant thin plate member that is press-fitted into the shaft and disposed at the end surface of the molding member and integrally formed with the magnet. When the shaft into which the thin plate material is press-fitted is inserted into a molding die, the thin plate material is in close contact with the molding die, and the gap between the molding die and the shaft is closed with the thin plate material. This is a featured stepping motor manufacturing method , which has the effect of eliminating the problem that burrs occur due to the thermosetting resin entering the gap between the shaft and the molding die.
[0010]
The invention according to claim 2 is the one in which the thin plate material according to claim 1 is made of a heat-resistant sliding material, and has an effect that a washer inserted into a sliding surface with the bearing can be omitted.
[0011]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[0012]
Example 1
In FIG. 1, a magnet 1 that is substantially cylindrical and multipolarly magnetized in the circumferential direction, a shaft 2 that is arranged coaxially with the magnet 1, and heat that couples the shaft 2 and the magnet 1. The molding member 3 is made of a curable resin, and a heat-resistant thin plate material 5 that is press-fitted into the shaft 1 and disposed at the end surface of the molding member 3 and is integrally molded with the magnet 1.
[0013]
When the shaft 2 into which the heat-resistant thin plate material 5 is press-fitted with the above-described configuration is inserted into the molding die 4, the heat-resistant thin plate material 5 comes into close contact with the molding die 4, and the gap between the molding die 4 and the shaft 2 is sealed. 5, it is possible to eliminate the occurrence of burrs due to the molding member made of a thermosetting resin entering the gap between the shaft 2 and the molding die 4. FIG. 2 is a structural diagram of a motor using the rotor 11 of this embodiment, and the configuration excluding the rotor is the same as the conventional one.
[0014]
(Example 2)
In FIG. 1, the heat-resistant thin plate material 5 is made of a sliding material. FIG. 3 is a structural diagram of a motor using the rotor 11 of the present embodiment. Compared with the first embodiment, the washer inserted on the sliding surface with the bearing can be omitted.
[0015]
【The invention's effect】
As is apparent from the description of the above embodiment, according to the invention described in claim 1, it is possible to eliminate a problem in which a molding member made of a thermosetting resin enters a gap between the shaft and the molding die to generate burrs. Therefore, it is possible to provide an advantageous effect that a motor having a rotor with high reliability and good productivity can be provided.
[0016]
According to the second aspect of the invention, the washer inserted into the sliding surface with the bearing can be omitted, and an inexpensive motor can be obtained.
[0017]
In addition, by using the stepping motor according to the present invention, it is possible to obtain a highly reliable or inexpensive information-related device such as a printer.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a rotor and a molding die of a stepping motor according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view of a stepping motor according to Embodiment 1 of the present invention. Cross-sectional view of a stepping motor [FIG. 4] Cross-sectional view showing a rotor and a molding die of a conventional stepping motor [FIG. 5] Cross-sectional view of a conventional stepping motor [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Magnet 2 Shaft 3 Molding resin consisting of thermosetting resin 4 Molding die 5 Heat-resistant thin plate material 6 Stator 7 Coil 8 Yoke 9 Oil-impregnated metal bearing 10 Washer 11 Rotor

Claims (2)

A magnet that is substantially cylindrical and multipolarly magnetized in the circumferential direction; a shaft that is coaxially disposed with the magnet; and a molded member made of a thermosetting resin that couples the shaft and the magnet; A method of manufacturing a stepping motor having a rotor having a heat-resistant thin plate material that is press-fitted into the shaft and arranged at a position of an end surface of the molding member and integrally formed with the magnet, the shaft into which the thin plate material is press-fitted A method of manufacturing a stepping motor, wherein when the sheet metal is inserted into a molding die, the thin plate material comes into close contact with the molding die, and a gap between the molding die and the shaft is closed with the thin plate material . 2. The method of manufacturing a stepping motor according to claim 1, wherein the thin plate material is a heat-resistant sliding material.

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