Eccentric rotor and compact vibrator motor including the eccentric rotor

Abstract

An eccentric rotor including a printed wiring commutator device where a hole for shaft installation is formed at the center thereof and a plurality of segment patterns are formed at the periphery of one surface thereof, a winding type armature coil integrally formed in a non-mold manner so as to be eccentric toward the other surface of the printed wiring commutator device, an end connection portion installed at such a position at the outer circumferential portion of the printed wiring commutator device that latching an end portion of the winding type armature coil is possible within a range of not deviating from the turning circumference during rotation and simultaneously electrical connection with the segment patterns is possible, and also at the position of not overlapping the winding type armature coil viewed from a plane, a resin bearing holder inserted in the shaft installation hole so that part thereof protrudes toward the segment pattern and simultaneously the other part thereof is extended toward the other surface of the printed wiring commutator device, and a resin eccentric weight exhibiting density of over 3 installed at the printed wiring commutator device. Thus, connection between each end of the armature coil and the commutator in an built-in type non-mold eccentric rotor is made easy and contact of the eccentric rotor becomes simplified.

Description

BACKGROUND OF THE INVENTION[0001] 1. Field of the Invention[0002] The present invention relates to an eccentric rotor used as a silent call device for a mobile communications apparatus, a compact vibrator motor having the rotor and a method of manufacturing the rotor, and more particularly, to an improvement of assembly and structure of an eccentric rotor which does not require an eccentric weight.[0003] 2. Description of the Related Art[0004] Referring to FIG. 21, as a silent call device for a pager or a mobile phone, an eccentric weight W made of tungsten alloy is coupled to an output shaft S of a cylindrical DC motor M. When the motor M rotates, vibrations are generated due to the difference in centrifugal force of the eccentric weight W.[0005] However, as the above addition of the eccentric weight W to the output shaft S requires a space for rotation of the eccentric weight W in an apparatus such as a pager, there is a limit in designing the apparatus. Also, use of the expensive...

AI Technical Summary

Benefits of technology

[0033] The above objectives and advantage of the present invention will become more apparent by describing in detail preferred embodiments thereof with reference to the attached drawings in which:

[0034] FIG. 1 is a cross sectional view showing a compact vibrator motor having an eccentric rotor according to the first preferred embodiment of the present invention;

[0035] FIG. 2 is a vertical sectional view of the motor of FIG. 1;

[0036] FIG. 3 is a vertical sectional view of a modified example of the motor of FIG. 1;

[0037] FIG. 4 is a view for explaining the principle of operation of the above motor;

[0038] FIG. 5 is a cross sectional view showing a motor according to the second preferred embodiment of the present invention;

Problems solved by technology

However, as the above addition of the eccentric weight W to the output shaft S requires a space for rotation of the eccentric weight W in an apparatus such as a pager, there is a limit in designing the apparatus.

Also, use of the expensive tungsten alloy increases the production costs.

However, as the motor requires three cylindrical coreless coils, the number of parts or processing steps increases, thus increasing the production costs.

However, for a portable apparatus such as a portable terminal using a low voltage, as the portable apparatus is small, movement of the center of mass is little and the amount of vibrations is insufficient.

However, as the three armature iron cores made of magnetized material are distributed at one angular side and cogging torque (a force of being absorbed by a field magnet) increases in the case of the motor, pores needs to be enlarged and the diameter of the motor itself cannot be reduced.

Thus, connection of the end portion thereof to the commutator without damage to the armature coil is very difficult.

Particularly, when a printed circuit board is used as a flat panel commutator as it is, where the end portion of the armature coil is directly welded thereon, welding of the end portion is not easy as the end portion is easily detached from a printed pattern due to elasticity of the end portion.

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