Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
1999-12-29
2003-01-14
Le, Dang Dinh (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S237000, C310S081000
Reexamination Certificate
active
06507136
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an eccentric commutator used as a silent call device for a mobile communications apparatus and an improvement in assembly and structure of a compact vibrator motor using the eccentric commutator.
2. Description of the Related Art
Conventionally, as a silent call device for pagers or mobile phones, as shown in
FIG. 8
, an eccentric weight W formed of tungsten alloy is coupled to an output shaft S of a cylindrical DC motor M. During rotation of the motor M, vibrations are generated due to the difference in centrifugal force of the eccentric weight W.
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.
Thus, the present applicant has suggested a cylindrical coreless vibrator motor in Japanese Patent Application No. Hei 2-309070 and the corresponding U.S. Pat. No. 5,107,155, in which a built-in rotor itself is made eccentric excluding an output shaft. The above motor having no output shaft and no eccentric weight is favorably noticed by the market as there is no limit in design, use thereof is easy and there is no danger during rotation. However, as the motor requires three cylindrical coreless coils, the number of parts or processing steps increases.
In order to make a rotor with an iron core itself vibrate instead of the cylindrical coreless coil type core, the present applicant has suggested removing one of three salient pole type iron cores as disclosed in Japanese Patent Application No. Hei 2-294482. The above two salient pole type iron cores are preferable in the case of a motor such as a massager needing a relatively large amount of output. However, for a portable apparatus such as a portable terminal consuming a low voltage, movement of the center of mass is little and the amount of vibration is insufficient.
Also, as disclosed in U.S. Pat. No. 5,341,057, the present applicant has suggested a compact vibrator motor having an eccentric armature iron core which is formed by arranging a rotor in which three salient poles made of magnetized material are distributed at one side, to face a tetrapolar field magnet having four alternate north and south pole sections. Also, the same technical concept has been disclosed in Japanese Laid-open Patent Application No. Hei 9-261918. However, as the three armature iron cores made of magnetized material are distributed at one side and cogging torque (a force of being absorbed by a field magnet) increases in the case of the motor, the gap of the motor needs to be enlarged and the diameter of the motor itself cannot be reduced.
In the above motor having a built-in type eccentric rotor, as the size of the above motor is reduced, the distance between armature coils decreases. Thus, connection of an end portion of the armature coil 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 because the end portion is easily detached from a printed pattern due to an elastic force of the end portion.
Also, as the commutator itself is generally a balanced circular shape, the number of parts such as an additional eccentricity emphasizing member increases in the built-in type eccentric rotor.
SUMMARY OF THE INVENTION
To solve the problems described, it is an objective of the present invention to provide an eccentric commutator for a vibrator motor with connection terminals that extend beyond air-core armature coils so that assembly of the vibrator motor and connection of the air-core armature coils is simplified in manufacturing the vibrator motor.
According to one aspect of the invention, an eccentric commutator includes a commutator base member comprising a printed wiring plate; a plurality of commutator pieces on a first side of the commutator base member; a resin shaft receiving portion, having a through-hole into which a shaft rotatably supporting the commutator base member is to be inserted, supporting the commutator base member, located partially on a second side of the commutator base member, passing through the commutator base member, and protruding to and partially located on the first side of the commutator base member; air-core armature coil position determination fixation fitting wedges located on the second side of the commutator base member, beyond the resin shaft receiving portion; at least two air-core armature coils fixed to the second side of the commutator base member on the air-core armature coil position determination fixation fitting wedges, each air-core armature coil having first and second ends; a resin portion positioned between the air-core armature coils, and eccentric relative to the resin shaft receiving portion, the resin portion including a resin and a metal component and having a specific gravity of at least 3; and air-core armature coil end connection terminals located outside the air-core armature coils, on the commutator base member, and respectively connected to the first and second ends of each air-core armature coil.
According to another aspect of the invention, an eccentric commutator includes a commutator base member comprising a printed wiring plate; a plurality of commutator pieces on a first side of the commutator base member; a resin shaft receiving portion, having a through-hole into which a shaft rotatably supporting the commutator base member is to be inserted, supporting the commutator base member, passing through the commutator base member, located partially on a second side of the commutator base member, protruding to and partially located on the first side of the commutator base member, and having a dynamic frictional coefficient of no more than 0.4 (1.5 kg/cm
2
); air-core armature coil position determination fixation fitting wedges located on the second side of the commutator base member, beyond the resin shaft receiving portion; at least two air-core armature coils fixed to the second side of the commutator base member on the air-core armature coil position determination fixation fitting wedges, each air-core armature having first and second ends; a resin portion positioned between the air-core armature coils and eccentric relative to the resin shaft receiving portion, the resin portion including a resin and a metal component and having a specific gravity of at least 3; and air-core armature coil end connection terminals located outside the air-core armature coils, on the commutator base member, and respectively connected to the first and second ends of each air-core armature coil.
It is a second objective of the present invention to provide an eccentric commutator in which intensity of a commutator member having a particular shape is secured.
It is a third objective of the present invention to provide a structure of an eccentric commutator in which connection of each end is easy because an end connection portion is separated from an armature coil.
It is a fourth objective of the present invention to provide an eccentric commutator which can receive a shaft as it is.
It is a fifth objective of the present invention to provide a vibrator motor using the above eccentric commutator, which needs less parts and is low in cost.
The above objectives can be achieved, by an eccentric commutator made by forming a plurality of commutator pieces on a commutator base member formed as a printed wiring plate, in which high density resin having a specific gravity of 3 or more is added to at least a part of the commutator base member and a shaft receiving portion is simultaneously is provided at the center thereof by making at least the high density resin portion to be eccentric.
It is preferred in the present invention that the high density resin has a specific gravity of 5 through 12
Dinh Le Dang
Tokyo Parts Industrial Co., Ltd.
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