JP3420862B2 - Axial gap type vibration motor with eccentric weight - 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 an axial gap type vibration motor with an eccentric weight, which is used for a radio notification means of a portable radio communication device.

[0002]

2. Description of the Related Art An eccentric weight W made of a tungsten alloy is provided on an output shaft S of a cylindrical motor M as a silent notification means of a portable radio communication device such as a pager as shown in FIG. It is known that vibration is obtained by utilizing centrifugal force.

However, in the case where the eccentric weight is added to the output shaft, the turning point of the eccentric weight must be taken into consideration on the set maker side, and the eccentric weight is exposed during rotation. Since it is dangerous, the shaft may be deformed if an impact such as a direct drop is applied to the eccentric weight.

Especially in the flat type motor, since the eccentric weight must be thinned, the danger at the time of turning is further increased. As shown in FIG. 5, when the eccentric weight WW is attached to the shaft S with a large dimension. Otherwise, in addition to impact such as dropping, the eccentric weight may be inadvertently held and deformed.

In order to overcome the above drawbacks, the present applicant has proposed Japanese Patent Application No. 63-11868, in which the eccentric weight is deleted so that the rotor itself is eccentric so that vibration can be obtained during rotation. That is, as shown in FIG. 6, the three armature coils 1a, 1b, and 1c are arranged so as not to overlap each other and so that their planes are substantially fan-shaped, and are integrally resin-molded. 1 is used, and vibration is generated by the eccentric rotor 1 during rotation.

[0006]

The above-mentioned eccentric rotor itself generates vibration, and in the case of an eccentric coreless motor having a diameter of 14 mm or more, the center-of-gravity movement amount is large, and relatively large vibration is obtained. Although it is well-received in the market, when the ultra-thin shape with a diameter of 12 mm or less is required, the deviation of the center of gravity from the center decreases,
High density eccentric weights must be attached to the rotor as ancillary means.

In this case, it is necessary to consider the turning space of the eccentric weight, which causes a problem of deformation when the eccentric weight is dropped. To avoid this, the eccentric weight is attached to the anti-magnet side of the rotor. A structure is also possible, but
This causes a decrease in the operating point permeance coefficient, which is represented by the ratio of the air gap size to the thickness of the magnet.Moreover, since this eccentric weight is conductive, eddy current loss occurs when it is placed in a magnetic field, and the characteristics It is no longer desirable.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a flat vibration motor with an eccentric weight which is highly compact and efficient without causing a reduction in the operating point permeance coefficient even though the eccentric weight is provided on the rotor. It is in. Another object of the present invention is not to give special consideration to the swirl space of the eccentric weight, that is, to prevent danger, and to secure sufficient mounting strength of the eccentric weight to sufficiently prevent impact such as dropping. To endure.

[0009]

In order to solve the above problems, a housing for rotatably supporting a rotor (R) through a shaft (2) as in the invention shown in claim 1.
(H) , a magnet (5) arranged in a part of the housing for giving a magnetic force to the rotor, and a power feeding means (6) arranged inside the magnet for supplying electric power to the rotor.
And an eccentric weight which is arranged on the rotor and generates a centrifugal force.
In the axial air gap type motor consisting of (9) , the rotor has a rising portion (7) provided in the axial direction,
The yoke plate (1
1) is arranged on a part (10) of the housing,
When the core weight is attached to the rising part (7),
Both are opposed to the yoke plate with a gap, and
A cover 12 is attached to cover the eccentric weight.
This can be achieved by having the tip of the shaft supported by the cover . As a means for solving the above problems, as in the invention described in claim 2, the rising portion (7) is formed in a ring shape surrounding the shaft, and the eccentric weight (9) has the ring rising portion. This can also be achieved by providing a mounting hole (9a) surrounded by. As a means for solving the above problems, as in the invention according to claim 3, the rotor is provided with a rising portion outside the rising portion, and the eccentric weight is formed by these rising portions (7, 8). It can be achieved by sandwiching between. More specifically, as in the invention described in claim 4, the eccentric weight can be achieved by being attached by crushing at least a part of the rising portion (7, 8).

[0010]

According to the means for solving the problems described in claim 1, since the yoke plate interposed between the rotor and the eccentric weight eliminates the loss of the operating point permeance coefficient and increases the characteristics, the characteristics are improved and the cover is used. The eccentric weight will be protected. According to the problem solving means described in claim 2, the eccentric weight can be attached with good strength. According to the problem solving means of the third aspect, the eccentric weight can be attached more favorably by the rising portion of the rotor. According to the problem solving means described in claim 4,
The eccentric weight can be attached easily.

[0011]

[First Embodiment] A first embodiment of the present invention will be described below with reference to a sectional view of a main part shown in FIG. That is, a base 2a of a shaft 2 is fixed to the center of a dish-shaped bracket 1 that constitutes a part of the housing H, and a plurality of armature coils 3 are integrally molded on the shaft 2 with a slidable resin J. R is loosely fitted. In this rotor R, the armature coil 3 is placed on the other surface of the glass cloth epoxy thin plate 4 on one surface of which the commutator 4a is printed and wired, and its end 3a is connected to the commutator 4a through a predetermined pattern (a predetermined pattern). (Not shown) is soldered and then integrated with the resin J.

Below the rotor R, a neodymium magnet 5 is mounted on the bracket 1 via a gap. Inside the magnet 5, a pair of positive and negative brushes, which are a part of the power feeding means, are installed. 6 (only one of which is shown in the drawing) is planted in the bracket 1 via a brush base 6a made of a flexible substrate. The brush base 6a passes under the magnet 5 and is led out to the outside as a power supply terminal 6b. On the anti-commutator side of the rotor R, there are further provided riser portions 7 and 8 made of resin J and integrally formed of two rings.
A half-moon shaped eccentric weight 9 formed by sintering a tungsten powder is also bonded. The mounting hole 9a of the eccentric weight 9 is surrounded by a step 9b so as to be lower than the rising portions 7 and 8. After mounting the eccentric weight 9, the head of the outer rising portion 8 should be crushed. By this, it is more firmly fixed.

A shallow cylindrical case 10 which is a part of the housing is attached to the outer periphery of the bracket 1 by caulking or the like, and a step portion 10a arranged in the middle of the case 10 has a feature of the present invention. Which is a yoke plate 11
However, it is locked so that a predetermined gap is maintained between the rotor R and the eccentric weight 9. The yoke plate 11 is further sandwiched by an inverted cup-shaped cover 12 fitted from above, and the edge 10b of the case 10 is sandwiched.
The cover 12 is firmly fixed together by crimping the inside. At the center of the cover 12, the shaft 2
One end 2b of the shaft is fitted and supports the shaft 2 together with the bracket 1.

In order to rotatably support the rotor R on the fixed shaft 2, the rotor R is supported vertically by 2 in order to suppress the inclination of the rotor R.
Equipped with bearings at several locations. That is, the lower bearing Ja
Is molded integrally with a high-sliding resin for rotor molding at the same time as molding, and the upper bearing Jb is a washer type and is inserted later.
The upper bearing Jb may be made of the same material as the rotor or may be a metal oil-impregnated bearing. In addition, Jc is a thrust washer inserted for the purpose of further preventing brake loss, and is the brush 6
It is always in sliding contact with the ceiling portion of the cover 12 with the pushing up urging force. Therefore, there is no possibility that the rotor will fall and come into contact with the magnet side.

With this configuration, by supplying positive and negative electric power to the power supply terminal 6b, the armature coil 3 is energized via the brush 6 and the commutator 4a, and the rotor R receives the magnetic force of the magnet 5. Although it rotates, centrifugal force is generated by the eccentric weight 9 and large vibration is obtained.

[0016]

[Second Embodiment] Although the shaft fixing type is illustrated in the above embodiment, the shaft may be rotated as shown in the sectional view of the main part of FIG. That is, the shaft 22 is formed integrally with the rotor RR by forming the rotation stopper 22c, and is rotatably supported by the bearings 1a and 12a arranged on the bracket B and the cover 12. Since other members are the same as those in the first embodiment, the same reference numerals are given and the description thereof is omitted. In this example, the outer circumference of the bracket B is raised upward and the case 10 is omitted.

[0017]

As described above, according to the present invention, even if the eccentric weight is arranged on the rotor, the yoke plate arranged between the rotor and the eccentric weight allows the operating point permeance coefficient to be large and the eccentric weight. Since it is possible to prevent an overcurrent even if it is electrically conductive, it is possible to provide an efficient flat vibration motor despite its small size.

[Brief description of drawings]

FIG. 1 shows a first flat vibration motor with eccentric weight according to the present invention.
FIG. 3 is a cross-sectional view of a main part of the embodiment.

FIG. 2 is a perspective view of an eccentric weight in FIG.

FIG. 3 is a cross-sectional view of a main part of a second embodiment of a perspective view of an eccentric weight according to the present invention.

FIG. 4 is a perspective view of a conventional general vibration motor.

FIG. 5 is a front view of a flat vibration motor in which a conventional eccentric weight is attached to an output shaft.

FIG. 6 is a plan view of a rotor of a vibration motor without a conventional eccentric weight.

[Explanation of symbols]

H housing 1 bracket 2 axes 3 armature coil J Sliding resin R rotor 4 thin plates 5 magnets 6 brushes 7,8 Startup section 9 Eccentric weight 10 cases 11 York board 12 covers

Claims (4)

(57) [Claims] 1. A housing (H) for rotatably supporting a rotor (R) via a shaft (2) , and a magnet (5) arranged in a part of the housing for giving a magnetic force to the rotor.
When, this power supply means for supplying power to said rotor disposed inwardly of the magnet (6), in the axial direction gap type motor consisting eccentric weights produce centrifugal force arranged in said rotor (9), said rotor Has a rising part (7) provided in the axial direction and has a gap with respect to the rotor
So that the yoke plate (11) is part of the housing (1
0), and the eccentric weight is attached to the rising portion.
(7) and the yoke plate with a gap
Facing each other and further covering the eccentric weight.
12 is attached, and the tip of the shaft is supported on this cover.
Eccentric weight with axial air-gap type vibration motor being. 2. The rising portion (7) is formed in a ring shape surrounding the shaft, and the eccentric weight (9) is provided with a mounting hole (9a) surrounding the ring-shaped rising portion. An axial gap type vibration motor with a flat weight according to claim 1. 3. The rotor according to claim 1, further comprising a start-up portion provided outside the start-up portion, and the eccentric weight is mounted between the start-up portions (7, 8). Axial air gap type vibration motor with flat weight. 4. The axial gap type vibration motor with an eccentric weight according to claim 3, wherein the eccentric weight is attached by crushing at least a part of the rising portion (7, 8).