JP2000092804A - Extremely small flat coreless vibrating motor with enlarged vibration - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an flat coreless vibrating motor which has an extremely small size and a simple constitution and can securely case vibrations similar to a large-sized motor. SOLUTION: A flat coreless vibrating motor is provided with an eccentric rotor 9 which is formed by integrally molding a synthetic resin with an armature coil on one side, a shaft which is passed through the center of the rotor 9, and a housing which rotatably supports the rotor 9. The motor is also provided with magnets 3 which are arranged in part of the housing and supply magnetic fluxes, brushes which are arranged inside the magnets 3 at the portion of the housing, and a commutator 10 which is arranged so that the front ends of the brushes may slide on the commutator 10. In the motor, in addition, an auxiliary weight (w) composed of a high-density synthetic resin having a specific gravity of >=7 is attached to the rotor 9 on the side opposite to the magnets 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a flat coreless vibration motor used as a silent call means of a mobile communication device, and more particularly to an ultra-small flat coreless vibration motor ensuring a sufficient vibration amount.

[0002]

2. Description of the Related Art A conventional flat coreless vibration motor is disclosed in, for example, Japanese Patent Application Laid-Open No. 63-290140.
An eccentric plate may be provided on the output shaft of a normal rotary motor,
There is one in which a part of three armature coils arranged equally at every 0 ° is deleted. There is also a conventional flat coreless vibration motor in which one of three armature coils is smaller than the others. Such a vibration motor is disclosed in USP 486.
4276.

However, it is difficult to make the output shaft provided with an eccentric plate thin, and a part of the three equally arranged armature coils is deleted or short-circuited or one armature coil is short-circuited. If the armature coil is small, it will still be a disk as a whole, so the amount of movement of the center of gravity will be small, the centrifugal force generated during rotation will be small, and the feeling of high frequency will not be good There is a disadvantage that it causes vibration.

[0004]

In order to overcome the above-mentioned deficiencies, the present applicant has previously filed Japanese Utility Model Application No. 63-11186.
No. 8 (Application changed to Japanese Patent Application No. 4-295503) and as disclosed in US Pat.
There has been proposed a rotor comprising a plurality of armature coils which are arranged so as not to overlap each other and are offset so that the plane as a whole is substantially fan-shaped.

[0005] More specifically, as shown in FIGS. 4 and 5, an eccentric rotor 9 having three armature coils a, b and c deviated to one side and a shaft disposed at the center of the eccentric rotor 9. 7, a housing 1 comprising a case 1 and a bracket 2 for rotatably supporting the eccentric rotor 9 via the shaft 7 and bearings 12a and 12b, and the eccentric mounted on the bracket 2 which is a part of the housing. A magnet 3 for supplying a magnetic flux to the rotor 9, a brush 6 disposed inside the magnet 3 via a brush base 4, and the end of the brush 6 slidably contacting the magnet 3 side of the eccentric rotor 9. The commutator 10 is provided on one side. In the drawing, reference numeral 8 denotes a brass retaining stopper, which becomes unnecessary if a retaining means such as a knurl is provided on the shaft itself. Numeral 11 denotes an integrally molded synthetic resin for the eccentric rotor 9, and usually, glass fiber reinforced polybutylene terephthalate is used. 13a and 13b are thrust washers.

The vibration motor having such a structure has a large amount of movement of the center of gravity in the radial direction, and therefore has a large centrifugal force generated at the time of rotation. There is an increasing demand for vibration motors that are smaller and have a centrifugal force. Eccentricity (movement of center of gravity)
In order to increase the weight, it is conceivable to integrally form a weight such as a lead ball on the synthetic resin part excluding the armature coil, but the size to be integrated cannot be made larger than expected, and the effect is thin, like a copper plate With a metal plate attached,
There is a problem that the loss due to the eddy current increases. Recently, as the set itself is becoming lighter, it is required that the motor to be mounted be lighter and have a larger vibration, and it is necessary to balance these conflicting functions.

The present invention has been made in view of the above-mentioned market needs, and has as its object to secure a vibration amount similar to that of a large-sized motor with a small and simple configuration.

[0008]

In order to solve this problem, the above-mentioned conventional structure, that is, an armature coil is disposed on one side and integrally formed of a synthetic resin as set forth in claim 1 is provided. An eccentric rotor, a shaft arranged at the center of the eccentric rotor, a housing rotatably supporting the eccentric rotor via the shaft, and a magnetic flux supplied to the eccentric rotor by being arranged on a part of the housing. The flat coreless vibration motor, comprising: a magnet; a brush disposed on a part of the housing inside the magnet; and a commutator disposed on the eccentric rotor such that a tip of the brush slides. This can be achieved by providing an auxiliary weight made of a high-density synthetic resin having a specific gravity of 7 to 12 on the anti-magnet side of the rotor. Specifically, it is preferable that the auxiliary weight is integrally formed with the eccentric rotor by providing a separation preventing means. Still further, the eccentric rotor is made of a synthetic resin having a high density and a high slidability having a specific gravity of 5 or more through a central bearing hole. Alternatively, it may be directly rotatable on a shaft fixed to a part of the housing.

[0009]

FIG. 1 is a sectional view of a main part of a flat coreless vibration motor according to the present invention, FIG. 2 is a cross-sectional view of an eccentric rotor used in the flat coreless vibration motor, and FIG. It is principal part sectional drawing which shows 2nd Embodiment.

1 and 2, an eccentric rotor 9 in which three armature coils a, b and c are biased to one side and a shaft 7 disposed in the center of the eccentric rotor 9.
And a housing comprising a bracket 1 and a case 1 rotatably supporting the eccentric rotor 9 via the shaft 7 and bearings 12a and 12b, and the eccentric rotor mounted on the bracket 2 which is a part of the housing. 9, a brush 6 arranged inside the magnet 3 via a brush base 4,
And a commutator 10 disposed on the entire surface of the eccentric rotor 9 on the magnet 3 side so that the tip of the eccentric rotor 9 slides. The eccentric rotor 9 basically has the same planar shape as that of the conventional one, that is, the three armature coils aa, bb and cc are biased to one side so as not to overlap each other at an arrangement pitch of 60 °. However, here, the three armature coils aa, bb and cc are made thin, and a specific gravity of 7 to 1 made of nylon containing tungsten powder is used.
It is characterized in that two auxiliary weights W are placed.
The auxiliary weight W is provided with a chamfer Wa on its upper surface so that it does not come off during integral molding. Such an auxiliary weight W increases in vibration amount when the specific gravity is increased, but becomes brittle when the specific gravity exceeds 12, and there is a concern about eddy current. When the specific gravity is 7 or less, it is not possible to greatly contribute to the vibration amount.

FIG. 3 is a sectional view of a main part of a fixed-shaft flat coreless vibration motor according to a second embodiment of the present invention. That is, a thin shaft 77 is fixed to the center of the bracket 22, and the shaft 77 is rotatably supported by an eccentric rotor 99 having a low friction coefficient and a high density and high slidability resin having a density of about 5 integrated inside. are doing. The eccentric rotor 99 is further provided with three armature coils aa, bb and cc which are biased to one side so as not to overlap each other at an arrangement pitch of 60 °. aa,
A flat plate commutator 110 made of a printed wiring board that is not located outside the outer periphery of bb and cc is integrated. The distal end of the thin shaft 77 is made to penetrate into the through hole 1a of the case 1 via the slidable washer 14 so as to withstand a side impact. Other configurations are the same as those described above, and the same reference numerals are given, and description thereof is omitted.
This eliminates the need for two bearings and facilitates assembly.

[0012]

As described above, the present invention provides an eccentric rotor in which an armature coil is disposed on one side and integrally formed of synthetic resin, and an eccentric rotor disposed at the center of the eccentric rotor. A shaft, a housing rotatably supporting the eccentric rotor via the shaft, a magnet arranged in a part of the housing to supply a magnetic flux to the eccentric rotor, and the housing inside the magnet. And a commutator disposed on the eccentric rotor such that the tip of the brush is in sliding contact with the eccentric rotor. With a simple configuration in which an auxiliary weight made of a high-density synthetic resin is attached, a vibration amount similar to that of a large-sized motor can be secured. More specifically, the workability is good if the auxiliary weight is provided integrally with the eccentric rotor by providing a separation preventing means. Still further, the eccentric rotor is made of a synthetic resin having a specific gravity of 5 with an armature coil disposed on one side and integrated therewith.
If it is made to have the above-mentioned high density and high slidability, and it is made rotatable directly on a shaft fixed to a part of the housing through the central bearing hole, the assembling work is simple and the vibration amount can be increased.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a flat coreless vibration motor of the present invention, and FIG. 2 is a transverse sectional view of an eccentric rotor used in the motor.

FIG. 2 is a transverse sectional view of an eccentric rotor used for the motor.

FIG. 3 is a sectional view of a main part of a flat coreless vibration motor according to a second embodiment of the present invention;

FIG. 4 is a sectional view of a main part of the conventional motor.

FIG. 5 is a plan view of the eccentric rotor of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Case 2, 22 Bracket 3, 33 Magnet 6 Brush 7 77 Shaft 9, 99 Eccentric rotor 10, 110 Commutator

Claims (3)

[Claims] An eccentric rotor in which an armature coil is arranged on one side and integrally formed of synthetic resin, a shaft arranged at the center of the eccentric rotor, and the eccentric rotor is rotatable via the shaft. A housing that is supported, a magnet that is provided on a part of the housing and supplies magnetic flux to the eccentric rotor, and a brush that is provided on a part of the housing inside the magnet and that the brush is in sliding contact with the eccentric rotor. In a flat coreless vibration motor provided with a commutator disposed on the eccentric rotor, vibration generated by adding an auxiliary weight made of high-density synthetic resin having a specific gravity of 7 to 12 to the anti-magnet side of the eccentric rotor is increased. Ultra small flat coreless vibration motor. 2. The microminiature flat coreless vibration motor according to claim 1, wherein said auxiliary weight is provided integrally with said eccentric rotor with a separation preventing means. 3. The eccentric rotor is made of synthetic resin having an armature coil arranged on one side and integrated to have high density and high slidability with a specific gravity of 5 or more and a part of a housing through a central bearing hole. 2. The apparatus according to claim 1, wherein said shaft is rotatable directly on a shaft fixed to said shaft.
Or the ultra-small flat coreless vibration motor according to 2.