Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
1999-08-20
2001-01-23
Ramirez, Nestor (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S049540, C310S194000, C310S216055, C310S256000
Reexamination Certificate
active
06177751
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a miniature cylindrical radial-gap type rotary electric machine having improved mounting accuracy of stator yokes and handling such as assembly thereof and, more particularly, to a bobbin that allows positive positioning between the stator yokes and a rotary electric machine adopting the bobbin.
2. Description of the Prior Arts
Generally, an inner rotor type brushless DC motor has stator yokes arranged on the inside of a case of the motor and a rotor rotatably arranged at the center portion of the stator yokes wherein the stator yokes are excited to rotatably drive the rotor. A stator yoke comprises a salient pole composed of a plurality of laminated thin plates which is fitted into a bobbin and magnet wires wound around the bobbin. The stator yokes, thus fabricated are predetermined positions inside the case of the motor.
The inventor of the present application proposed in Japanese Patent Application No. 178687/1997 a rotary electric machine wherein resin is injected in between a case of the motor and a stator portion to form them into one piece. This proposal brings such advantages that filling of the resin allows the stator to be secured to the case with the result that assembling accuracy is improved and durability is increased.
However, in the above proposed motor a plurality of stator yokes must be secured to the inside of the case with accuracy, thus resulting in much labor and time for the assembly. For example, when a plurality of stator yokes are mounted on the inner surface of the case, if the center of the assembly is dislocated from the center of revolution of the rotor, or there is a variation of a distance between the stator yokes thus mounted, then torque ripple or cogging torque shall be increased with the result that the performance of the motor will be lowered.
Furthermore, in the rotary electric machine above-mentioned wherein resin is injected in the case of the motor, the stator yokes must be positively held at predetermined positions until the resin completely solidifys. In this case, there are problems in that weak holding of the stator yokes causes displacement thereof or dislocation of the center thereof thereby reducing the efficiency of the motor.
Furthermore, if the stator yokes are arranged so closely with each other at the edge portions thereof, resin flow will be blocked thus preventing resin from being filled in the whole stator yokes from the front to the rear surfaces thereof.
SUMMARY OF THE INVENTION
It is an object of the present invention to solve the foregoing problems and provide a rotary electric machine wherein stator yokes are positively positioned and secured so that smootly flow of resin is improved when the resin is filled in the armature portion including the case, and good durability is provided.
According to the present invention, a rotary electric machine is constituted as mentioned below in order to solve the foregoing problems.
That is, according to the present invention, in a cylindrical radial-gap rotary electric machine wherein a salient pole is inserted into the center of a bobbin, stator yokes in which magnetic wires are wound around said bobbins are radially arranged, and a rotor having a permanent magnet is rotatably provided against the salient pole of the stator yoke, both ends of the stator yoke bobbin are formed to contact with each other, whereby stator yokes can be arranged with accuracy by allowing an edge to contact with another edge and can be positively secured at predetermined positions as well.
Furthermore, notches are formed at the bobbin, for example, at contact portions on the edge of the bobbin, and through-holes are formed which penetrate the stator yoke. Accordingly, injecting resin in between the stator yokes and the case causes the resin to flow through the through-holes out to the front and rear surfaces of the bobbin, whereby the stator yokes are secured into one piece with the resin, and thus assembly work can be simplified and the mounting accuracy of the motor can be improved.
The through-holes may be not only notches or the like provided on the edge of the bobbin, but also holes that penetrate the bobbin itself.
Furthermore, the stator yoke may be provided, on the edge thereof, with a projection and depression so that other bobbins are mated with each other. This allows the stator yoke to be more secure when stator yokes are combined, and allows the securing force to be increased as well. The mating portion may have at least, but is not necessarily limited to, a projection and a depression that allows for no displacement between bobbins; the mating portion may be of a slidable type for assembly, may be provided with a pin and a hole for insertion, or may be mated with another one by bonding or adhesion.
Furthermore, such a rotary electric machine is possible in that the stator yoke may be provided on, but is not limited to, the outer circumference; the stator yoke may be arranged inside and a rotor outside.
REFERENCES:
patent: 2655613 (1953-10-01), Weiseman
patent: 2691113 (1954-10-01), Ordas
patent: 2870357 (1959-01-01), Vandenberg et al.
patent: 4795933 (1989-01-01), Sakai
patent: 359070160A (1984-04-01), None
patent: 403155347A (1991-07-01), None
Fujitani Sakae
Matsushita Kunitake
Muramatsu Kazuo
Nishio Taichi
Sano Hiroshi
Faye Sharpe, Fagan, Minnich & McKee LLP
Minebea Co. Ltd.
Perez Guillermo
Ramirez Nestor
LandOfFree
Rotary electric machine and bobbin thereof does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Rotary electric machine and bobbin thereof, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Rotary electric machine and bobbin thereof will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2474272