JP3257982B2 - Flat coreless vibration motor with large center of gravity shift - Google Patents

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 a flat coreless vibration motor having a large center of gravity.

[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. 63-111186.
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 with each other and are biased so that the plane as a whole is substantially fan-shaped.

More specifically, as shown in FIGS. 5 and 6, an eccentric rotor 9 in which three armature coils a, b and c are biased to one side, and a shaft arranged in 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 figure, 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 centrifugal force generated at the time of rotation because of a large amount of movement of the center of gravity in the radial direction. 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 part of the synthetic resin excluding the armature coil. However, the size to be integrated cannot be made larger than expected and the effect is thin. In recent years, as the set itself has become lighter in weight, a motor to be mounted is required to be lighter and more vibrant, and it is necessary to balance these contradictory functions.

The present invention has been made in view of the market needs as described above, and is intended to achieve a large vibration amount with a simple configuration without changing the size and without increasing the thickness and to achieve a reduction in weight. It is the purpose.

[0008]

According to the present invention, in the above-mentioned conventional construction, a high-density composite engineering plastic having a density of 5 or more containing metal on the outer peripheral side as a synthetic resin constituting an eccentric rotor, and This can be achieved by using a resin of 1.8 or less.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to an eccentric rotor (99, 999) in which armature coils (a, b, c,) are arranged on one side and integrally formed of synthetic resin. ,
A shaft (7, 77) arranged at the center of the eccentric rotor, a housing (1) for rotatably supporting the eccentric rotor via the shaft, and a housing comprising brackets (2, 22, 222); Part of the housing (2, 22, 22)
A magnet (33) arranged in 2) to supply a magnetic flux to the eccentric rotor, and a brush (6) arranged inside a part of the housing inside the magnet so that the tip of the brush slides. In a flat coreless vibration motor provided with a commutator (10, 110) disposed on the eccentric rotor, a high-density composite engineering plastic (M) having a density of 5 or more containing metal on the outer peripheral side as a synthetic resin constituting the eccentric rotor And the inside density 1.8
This can be achieved with the following resin (L). In this way, the amount of movement of the center of gravity in the radial direction from the center can be increased without increasing the overall weight of the rotor.

Further, the outer diameter of the magnet is made smaller than the turning outer circumference of the eccentric rotor, and the synthetic resin (M or M) is provided on the magnet side of the outer circumference of the eccentric rotor.
Or L) to form a convex portion (A), and a part of the convex portion
Includes high-density composite engineering plastic (M)
The protrusion (A) may be arranged in a space (123) between the outer periphery of the magnet and the housing (side peripheral portion of the case ) via a gap. By doing so, the amount of movement of the center of gravity in the radial direction from the center can be further increased.

Further, the shaft is fixed to a part (222) of the housing, and the shaft (7) is fixed.
7) The eccentric rotor (999) may be rotatably mounted via a highly slidable resin (L) having a density of 1.8 or less and also serving as a bearing. In this way, the density of 1.8
Since the following highly slidable resin is used as the bearing, two oil-impregnated bearings can be omitted.

The commutator (10, 110) disposed on the eccentric rotor is formed of a printed wiring board, and the outer periphery of the commutator is located inside the outer periphery of the armature coil. It is preferable to arrange a high-density composite engineering plastic (M) having a density of 5 or more on the outside. By doing so, the amount of movement of the center of gravity in the radial direction from the center can be further increased.

[0013]

FIG. 1 is a plan view of a main part of an embodiment of a rotor of a flat coreless vibration motor according to the present invention. The eccentric rotor 9 has basically the same planar shape as that of the prior art, that is, three armatures. The coils a, b and c are biased to one side so that they do not overlap each other at an arrangement pitch of 60 °.
As a resin for integrally molding these armature coils a, b and c, a high-density composite engineering plastic (a tungsten powder bound with polyamide) M having a density of 12 on the outer peripheral side and a resin having a density of about 1.4 on the inner side L. In the figure, K is a locking portion for preventing a high-density composite engineering plastic (a tungsten powder bound with polyamide) M from coming off. Note that the flat coreless vibration motor using the eccentric rotor 9 is the same as the conventional one shown in FIG. 5, and the description thereof is omitted here.

FIGS. 2 and 3 are a sectional view of a main part of a flat coreless vibration motor according to a second embodiment of the present invention and a plan view of a rotor of the motor. That is, the rotor 99 is arranged so that the three armature coils a, b, and c are biased to one side so as not to overlap each other at an arrangement pitch of 60 °. The ring-shaped neodymium magnet 33 has an outer periphery smaller than the turning outer diameter of the eccentric rotor and is fixed to the bracket 22 via an adhesive (not shown) in order to save resources. Have been. Therefore, the space 12 is provided between the outer diameter of the magnet 33 and the inside of the case 1.
3 will occur.

In this space 123, a convex portion A integrally formed of a high-density composite engineering plastic M extends on the outer periphery of the eccentric rotor 99 and is arranged via a gap. Other configurations are the same as those of the conventional FIG.
Therefore, the description is omitted.

FIG. 4 is a sectional view of a main part of a fixed-shaft flat coreless vibration motor according to a third embodiment of the present invention. That is, the thin shaft 77 is fixed to the center of the bracket 222, and the eccentric rotor 999 is rotatable at the center bearing part with a low friction coefficient and a high slidability resin having a density of about 1.5 on the shaft 77. I support it. The eccentric rotor 999 further has three armature coils a, b, and c arranged at an arrangement pitch of 6.
At 0 °, it is biased to one side so that it does not overlap each other , and
In the same manner as in the above-described embodiment, the flat commutator 110 formed of a printed wiring board that does not protrude from the outer periphery of the armature coils a, b, and c is integrated with the low friction coupling.
And a high slidability resin having a density of about 1.5 is extended and integrated, and a high-density composite engineering plastic M having a low friction coefficient and a density of 1.5 It is arranged so as to be included in the protruding portion A formed by extending a resin having a high degree of slidability. The distal end of the thin shaft 77 is made to penetrate into the through hole 1a of the case 1 via a slidable washer 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,
Assembly becomes easy.

[0017]

According to the present invention, as described above, the synthetic resin constituting the eccentric rotor is formed of a high-density composite engineering plastic having a density of 5 or more on the outer peripheral side and a resin having a density of 1.8 or less on the inner side. Can be increased without changing the center of gravity. Therefore, the weight can be reduced by the inner resin while securing the amount of vibration, so that it is possible to meet the demand for reducing the weight of the motor itself. In particular, when the convex portion A is provided on the outer periphery, the centroid moves further in the radial direction, so that the centrifugal force at the time of rotation becomes large, which is effective.

[Brief description of the drawings]

FIG. 1 is a plan view of a first embodiment of an eccentric rotor of a flat coreless vibration motor according to the present invention.

FIG. 2 is a plan view of the second embodiment.

FIG. 3 is a sectional view of a main part of a flat coreless vibration motor using the eccentric rotor of the embodiment of FIG. 2;

FIG. 4 is a sectional view of a main part of the motor according to a second embodiment of the present invention.

FIG. 5 is a sectional view of a main part of the conventional motor.

FIG. 6 is a plan view of the eccentric rotor of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Case 2,22,222 Bracket 3,33 Magnet 6 Brush 7 Shaft 9,99 Eccentric rotor 10,110 Commutator A Convex part M Resin with specific gravity 5 or more L Resin with specific gravity 1.8 or less

Claims (4)

(57) [Claims] An eccentric rotor (9) in which armature coils (a, b, c,) are arranged on one side and integrally formed of synthetic resin.
9, 999), a shaft (7, 77) disposed at the center of the eccentric rotor, a case (1) rotatably supporting the eccentric rotor via the shaft, and a bracket (2, 22,
222) , a magnet (33) arranged on a part (2, 22, 222) of the housing to supply a magnetic flux to the eccentric rotor, and a magnet (33) arranged on a part of the housing inside the magnet. And a commutator (10, 110) disposed on the eccentric rotor such that the tip of the brush is in sliding contact with the eccentric rotor. A flat coreless vibration motor having a large center of gravity, characterized in that the side is made of a high-density composite engineering plastic (M) containing metal and having a density of 5 or more and the inside is made of a resin (L) having a density of 1.8 or less. 2. An outer diameter of the magnet is made smaller than a turning outer circumference of the eccentric rotor, and a part of the synthetic resin on the armature coil side is convex on the magnet side on the outer circumference of the eccentric rotor. The convex portion (A) is arranged in the space (123) between the outer periphery of the magnet and the housing (side peripheral portion of the case ) through a gap, and the high density is partially provided on the convex portion. Composite engineering plastic
2. The flat coreless vibration motor according to claim 1 , wherein (M) is included . 3. The eccentric rotor (2) is fixed to a part (222) of a housing, and the shaft (77) is provided with a highly slidable resin (L) having a density of 1.8 or less and also serving as a bearing. 99
2. The flat coreless vibration motor according to claim 1, wherein the motor is mounted rotatably. 4. The commutator (10, 110) disposed on the eccentric rotor is made of a printed wiring board, and has a high density of 5 or more outside the commutator with the outer periphery being inside the outer periphery of the armature coil. The flat coreless vibration motor according to any one of claims 1 to 3, wherein a density composite engineering plastic (M) is provided.