Electrical generator or motor structure – Dynamoelectric – Rotary
Patent
1989-07-14
1990-11-13
Skudy, R.
Electrical generator or motor structure
Dynamoelectric
Rotary
310 42, 310 51, 310211, 74573R, H02K 122
Patent
active
049704249
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to the construction of a rotor for a high speed electric induction motor, and more particularly, to a reinforcing construction of aluminum end rings formed as integrated portions projecting from opposite ends of a rotor core when an aluminum material to be used as an electric conductor is poured by a die casting method, in a laminate-stacked core of a rotor, i.e., a rotor core.
BACKGROUND ART
An increase in the speed of rotation of motors to be used for driving the spindles of machine tools is urgently needed to satisfy current requirements for increasing the cutting and grinding speeds of machine tools. Alternate current electric induction motors are often used to drive the spindles of machine tools, and the rotor of the electric induction motor includes a rotor core usually formed by stacking a plurality of laminates obtained by punching from a silicone steel plate by a press machine, and cylindrical end rings formed by electroconductive aluminum material poured into opposite end portions of the rotor core, the aluminum material being also poured in the slots of the rotor core to form an electric closed circuit for the induction motor.
In the case of high speed electric induction motors, however, a problem arises in that the centrifugal force is increased in response to an increase in a speed of rotation of the induction motor, and such a large centrifugal force due to an increase in the motor speed causes a breakage of the aluminum end rings of the rotor. To prevent such breakage, the rotor of the electric induction motor has been designed and manufactured so as to have a small outer diameter.
It is well known that a high speed induction motor rotating at a high speed must be provided with a rotor which is dynamically balanced, and therefore, in a known construction of a high speed-induction motor, a balancing ring is disposed radially inside an aluminum end ring and is permanently attached to each axial end of the core of the rotor, whereby the rotor is dynamically balanced by drilling a balancing bore or bores in the balancing ring. At the same time, the balancing rings on the opposite ends of the rotor core are tightly engaged in the corresponding end rings of the rotor, to hold the rings in place against a centrifugal force acting on the aluminum end rings during a high speed rotation of the rotor of the induction motor.
In another conventional construction of a high speed induction motor, an iron ring is attached to the end ring of each of the opposite axial ends of the rotor by the press fit or shrink fit, to protect the end rings from breakage.
Nevertheless, the above-mentioned construction of the rotor for a high speed induction motor must still suffer from a problem such that the end rings of the rotor are apt to be broken due to a self expansion thereof caused by the Joule heat, and therefore, a further reinforcing of the end rings is needed. Particularly, the method of attaching the abovementioned iron ring to the end rings of the rotor brings an additional problem in that the process of manufacturing the high speed induction motors becomes complicated.
DISCLOSURE OF THE INVENTION
Therefore, an object of the present invention is to obviate the above-mentioned defects encountered by the high speed electric induction motor according to the prior art.
Another object of the present invention is to provide a construction of a rotor for a high speed electric induction motor, having sufficient strength to resist a centrifugal force acting thereon during a high speed rotation of the motor and a method of forming such a rotor.
A further object of the present invention is to provide a high speed electric induction motor by which the manufacturer thereof is simplified.
In accordance with the present invention, there is provided a construction of a rotor for a high speed electric induction motor including a stator capable of forming a rotatory magnetic field rotating at a high speed, the rotor having a stacked-lamination-type rotor core provided with axia
REFERENCES:
patent: 1134776 (1915-04-01), Thomson
patent: 1240018 (1917-09-01), Bergman
patent: 2436414 (1948-02-01), Arnemo
patent: 4309635 (1982-01-01), Sei et al.
patent: 4641886 (1987-02-01), Muck et al.
patent: 4760300 (1988-07-01), Yoshida et al.
Hayashi Yoshiyuki
Nakamura Kosei
Fanuc Ltd.
Skudy R.
LandOfFree
Rotor construction for high speed induction motor does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Rotor construction for high speed induction motor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Rotor construction for high speed induction motor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-778728