Motor core and motor using the same
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorHiroyasu Fujinaka
Life of this patent
Estimating the term…
Abstract
A motor generating cogging torque has one-quarter the cycle of basic cogging torque and an extremely small absolute value. First, in order to reduce the cycle of the cogging torque to one-half the cycle of the basic cogging torque, a basic configuration of the core is determined by setting opening angles of its slots to an appropriate electrical angle ranging from 80° to 95° and from 20° to 35°. Next, to produce the above-mentioned effects, an angular displacement of one-quarter the cycle of the basic cogging torque is provided in the motor. Furthermore, polarizing the core with a skew angle equal to one-half or less the cycle of the basic cogging torque at the same time allows the cogging torque to be reduced effectively while decrease in efficiency is minimized.
Claims9
A core for use in a motor, said motor including N and S magnetic poles for generating a magnetic field to which said core is opposed, said core comprising:
- a plurality of slots formed in said core,
- wherein said core is made of upper, middle, and lower thirds and pole winding parts of said core are made narrower in the upper and lower thirds than the middle third.
A motor including:
- (a) magnetic field generating means having N and S magnetic poles for generating a magnetic field;
- and
- (b) a core made of magnetic material and opposed to said magnetic field generating means;
- wherein one of said magnetic field generating means and said core rotates with respect to the other, and
- wherein said core is mode of upper, middle, and lower thirds, and pole winding parts of said core are made narrower in the upper and lower thirds than the middle third.
The motor described in claim 8 wherein
- in a case where said magnetic field generating means is a magnet, and a number of magnet poles is 2 m and a number of core slots is 3 n (m and n are integers), polarization is performed at a skew angle of (200/k)° or less in central angle (k is a least common multiple of 2 m and 3 n).
Dependencies are inferred from the claim text.