Patent Application
20080073996
Many aspects of the present motor stator can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present motor stator. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views:
Referring to
Each of the yokes 10a, 10b, 20a, 20b of the claw-pole assemblies 30a, 30b is ring-shaped with a circular hole 100 defined therein. A plurality of pole teeth 50 extends perpendicularly from an inner circumference of each yoke 10a, 10b, 20a, 20b. The pole teeth 50 of each yoke 10a, 10b, 20a, 20b are evenly spaced from each other along a circumferential direction thereof and thus define a plurality of slots 80 therebetween. Each of the pole teeth 50 has a shape and size the same as those of the other teeth 50. Each tooth 50 forms an arc-shaped free end. Each of the slots 80 has a size a little larger than that of the tooth 50 so as to receive a corresponding tooth 50 therein. Two pins 70 extend outwardly from an outer circumference of each inner yoke 20a, 20b. The pins 70 are integrally formed with the inner yokes 20a, 20b. The two pins 70 of each inner yoke 20a, 20b are spaced from and parallel to each other.
During assembly, each of the outer yokes 10a, 10b combines with a corresponding inner yoke 20a, 20b to form a claw-pole assembly. The inner yokes 20a, 20b and the outer yokes 10a, 10b of each claw-pole assembly 30a, 30b face to each other. The teeth 50 of each outer yoke 10a, 10b insert into the slots 80 of the corresponding inner yoke 20a, 20b. The teeth 50 of each inner yoke 20a, 20b insert into the slots 80 of the corresponding outer yoke 10a, 10b. Thus the pole teeth 50 of the two yokes 10a, 20a (10b, 20b) of each claw-pole assembly 30a (30b) are intermeshed with each other. Along the circumferential direction of the yokes 10a, 10b, 20a, 20b, the teeth 50 of the outer and inner yokes 10a, 20a (10b, 20b) of the claw-pole assembly 30a (30b) are arranged alternatively, and are misaligned from each other by an electrical angle of 180°. The teeth 50 of the yokes 10a, 20a (10b, 20b) of the claw-pole assembly 30a (30b) cooperatively form a cylinder-shaped sidewall 60. The outer and inner yokes 10a, 20a (10b, 20b) are located at two opposite ends of the sidewall 60. The circular holes 100 of the yokes 10a, 20a (10b, 20b) cooperatively define a through hole for receiving the rotor therein. Coils (not shown) wind around each sidewall 60 to generate an alternating magnetic field when a current is applied to the coils. The alternating magnetic field of the stator interacts with the magnetic field of a permanent magnet of the rotor to drive the motor into rotation. A narrow gap 62 is defined between each two neighboring pole teeth 50 of the sidewalls 60 for the relatively larger size of the slots 80 than the teeth 50. The gaps 62 between the teeth 50 are filled with resin inserted by insert molding, and thus fixedly combining the inner and outer yokes 10a, 10b (20a, 20b) together to form the claw-pole assembly 30a (30b).
The two claw-pole assemblies 30a, 30b are then arranged back-to-back. The four yokes are arranged in sequence: the outer yoke 10a, the inner yoke 20a of the upper claw-pole assembly 30a, the inner yoke 20b, and the outer yoke 10b of the lower claw-pole assembly 30b. The inner yokes 20a, 20b of the two claw-pole assemblies 30a, 30b abut each other and are located approximately in a middle of the stator. The outer yokes 10a, 10b of the two claw-pole assemblies 30a, 30b are spaced from each other. The outer yoke 10a of the upper claw-pole assembly 30a is located at a top end of the stator, whilst the outer yoke 10b of the lower claw-pole assembly 30b is located at a bottom end of the stator. The two claw-pole assemblies 30a, 30b are misaligned from each other by an electrical angle of 90°. The pins 70 of the two inner yokes 20a, 20b are alternatively arranged; one pin of each inner yoke 20a, 20b is located between the two pins 70 of the other inner yoke 20b, 20a. The four pins 70 are parallel to each other. The coils wound on each sidewall 60 of the claw-pole assembly 30a, 30b have two ends (not shown) connected to the two pins 70 of a corresponding inner yoke 20a, 20b. Thus the coils are electrically connected to a power source (not shown) by the pins 70. During operation of the motor, a current is applied to the coils to establish alternating magnetic filed, interacting with the magnetic field of the rotor to drive the rotor into rotation. As the pins 70 are integrally formed with the inner yokes 20a, 20b of the stator, production and assembly of the motor is simplified. Also the location of the pins 70 is more accurate and thus prevents separation from the stator; the coils thus can be connected to the pins 70 correctly, and thus avoid in-operation of the motor.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to accommodate various modifications and equivalent arrangements. The stator in accordance with the preferred embodiments of the present invention comprises two claw-pole assemblies 30a, 30b arranged back-to-back. The number of the claw-pole assemblies 30a, 30b can be changed according to the precision requirements of the motor, it can be only one, and it can also can be three or more. The number of the teeth 50 of each yoke 10a, 10b, 20a, 20b is also decided by the precision requirement of the motor, being not limited to the disclosed embodiments.
