JP2000224805A - Flat vibration motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flat vibration motor whose rotor has two armature coils to reduce a manufacturing cost and which has no activation starting point. SOLUTION: An annular stator 4 which is equally divided into four sections magnetized so as to have N-polarity and S-polarity alternately is arranged in a flat cylindrical casing 3. A semi-circular disc type rotor 5 is rotatably arranged in the casing 3 so as to face the stator 4. Two armature coils 11a and 11b are arranged on the rotor 5. An approximately fan-shaped weight member 20 is provided between the two armature coils 11a and 11b. A shaft-type magnetic element 21 is provided in the weight member 20 at a position close to one of the armature coils 11a and 11b so as to penetrate the weight member 20 from its one surface to the other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small flat type vibration motor used for notifying a mobile phone or the like of an incoming call by vibration.

[0002]

2. Description of the Related Art Conventionally, as a flat type vibration motor of this type, for example, a flat iron coreless vibration motor disclosed in Japanese Patent Application Laid-Open No. 6-205565 has been known. The flat iron coreless vibration motor includes a magnet portion fixed to a bottom portion of a casing, a rotatable substantially fan-shaped rotor arranged to face the magnet portion, and a main portion of the rotor. The rotor is composed of three armature coils arranged in a fan shape and molded integrally with a resin material. The eccentricity of the rotor itself reduces the centrifugal force during rotation of the rotor. It is designed so that it works to generate vibration, and that three armature coils are mounted on the rotor so that a starting dead center does not occur.

[0003]

However, in the above-mentioned flat type vibration motor, torque is generated by the magnetic field with the magnet for the three coils in which the current flows alternately, so that at least three coils are used. Will be needed. This is because, when the rotor stops with an armature coil having a rotation angle of about 90 degrees or less, no rotation force is generated in the armature coil positioned within the polarity of the magnet. It has not been possible to simply reduce the number of armature coils from a rotor having a number of armature coils.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems, to reduce the manufacturing cost by providing two armature coils provided on the rotor, and to provide a flat vibration motor having no starting point. .

[0005]

In order to solve the above-mentioned problems, a flat type vibration motor according to the present invention is characterized by having the following requirements. (A) A ring-shaped stator that is equally divided into four parts in the circumferential direction and that is alternately magnetized with N poles and S poles is disposed in a flat cylindrical casing. A rotatable, substantially semi-disc-shaped rotor is axially supported inside the rotor while being opposed to the stator, and two armature coils are symmetrically arranged on the rotor with respect to the support shaft of the rotor. (C) The rotor has a non-magnetic weight member provided in a substantially fan shape between the two armature coils, and the weight member has an axial magnetic material penetrating from one surface to the other surface. Is provided,
When the rotor is stopped, the magnetic body corresponds to the center of the magnetic pole of the stator. (D) The magnetic body is located near one of the armature coils at the circumferential end of the weight member. Be placed in

[0006]

1 and 2 show an exploded perspective view and a longitudinal sectional view of a main part of a flat type vibration motor (hereinafter referred to as a motor) according to the present invention. A ring-shaped stator 4 and a substantially semi-disc shape are provided inside a casing 3 comprising a flat cylindrical case 1 and a disc-shaped bracket 2 fitted into an opening at the lower end of the case 1. Of the rotor 5 are arranged.

The bracket 2 has a ring-shaped stator 4,
A commutator 10 described below provided on the lower surface of the rotor 5
Are arranged, and two brushes 12a and 12b are disposed to contact the armature coil 11 and to supply a current to the armature coil 11.
b, a positive brush 12a and a negative brush 1b are soldered on a brush base 13 formed so that a lead wire (not shown) can be soldered to an end and connected to a power source.
2b is disposed so as to contact the commutator 10 at an electrical angle of 90 degrees.

The stator 4 is divided into four equal parts in the circumferential direction, and each of the stators 4a, 4a,
b, 4c, and 4d, each stator is alternately magnetized to an N pole and an S pole, and two brushes 12a, 12
It is fixed on the bracket 2 by an appropriate means such as an adhesive so that the contact portions contacting the commutator 10 in b coincide with each other.

The rotor 5 is provided at a main part of the rotor 5 as shown in the plan view, the bottom view and the sectional view taken along the line XX 'in FIGS. 3 (a), 3 (b) and 3 (c). An armature coil 11 composed of two first and second armature coils 11a and 11b, each of which is a substantially fan-shaped flat plate having an opening angle of 90 degrees and symmetrically arranged with respect to the rotation shaft 16 provided therebetween, and the first electric motor A substantially semicircular plate-shaped weight member 13 formed of a nonmagnetic metal and formed in a substantially fan shape with an opening angle of 90 degrees disposed between the child coil 11a and the second armature coil 11b. Is formed integrally with a resin 15 on a commutator substrate 14 of FIG.
The commutator substrate 14 is fixed by a metal 18 fitted to an opening 17 formed at the center of the case 1 and a metal 18 fitted to an opening 19 formed at the center of the bracket 2 shown in FIG. The casing 4 faces the child 4 and is rotatably supported by the casing 3.

By the way, a small circular through hole 20 penetrating from one surface to the other surface is formed in the weight member 13 near the outer periphery and near the first armature coil 11a. 20 is a round shaft-shaped iron core (magnetic material) 21
Are fitted and fixed, and both ends of the iron core 21 are weight members 13.
It is formed in the length which becomes flush with. The above-mentioned iron core 21 is not limited to a round shaft shape as long as the cross-sectional area is small, and may be a prismatic shape.

FIG. 4A shows an armature coil 11.
FIG. 2 is a plan view of the commutator substrate 14 before the a, 11b and the weight member 13 are fixed with the resin 15;
Printed wirings 20a, 20b, and 20c for soldering the start end and the end of 1b, respectively, are formed. The start ends of the armature coils 11a and 11b are connected to the printed wirings 20a and 20b.
b, the armature coils 11a, 1
1b are soldered to the soldering portions 24 and 25 of the printed wirings 20c and 20a, respectively.
b and 20c pass through the through holes 31 to 33,
As shown in the bottom view of (b), each armature coil 11a,
11b, which are connected to commutators 10a, 10b, 10c, 10d formed on the back side of the commutator substrate 14 so as to correspond to the commutators 10a, 10b, 10c, 10c.
d and the armature coils 11a and 11b are connected as shown in the connection diagram of FIG. In FIG. 5A, reference numeral 35 denotes a resistor for preventing electric noise. FIG.
(B) is a development view showing relative positions of the rotor 5, the commutators 10a to 10d, the stators 4a to 4d, the contacts of the brushes 11a to 11b, and the magnetic body 21.

Next, with reference to FIG. 6, it will be described that no dead center is generated after the above-mentioned flat type vibration motor is stopped.

While a voltage is applied to the coil via the brush, a force acts on the coil in a fixed direction according to Fleming's law by the direction of the current flowing through the coil and the magnetic field of the stator. When no voltage is applied, no current flows through the coil, and the rotor stops rotating without being affected by the force of the magnetic field of the stator. Since the iron core 21 is formed of a shaft having a small cross-sectional area, any one of the four stators 4a to 4d is used as shown in FIGS. The rotor is stopped in a state where the iron core 21 is located in the middle of one of the magnetic poles, and the armature coil of the rotor can always be stopped at a position outside the boundary between the magnetic poles of the stator, and the brushes 12a, 12b Is always commutator 1 It can be stopped in contact with.

FIG. 6A shows a state in which the magnetic body 21 has stopped on the stator 4a, and FIG. 6B shows a state in which the magnetic body 21 has stopped on the stator 4b. FIG. 6C shows a state in which the magnetic body 21 stops on the stator 4c, and FIG.
(D) has shown the state where the magnetic body 21 stopped on the stator 4d, respectively.

When the rotor is stopped in the state shown in FIG. 6A, when a voltage is applied, the brush 12a, the commutator 10b, the armature coil 11b, the armature coil 11a, the commutator 10a, the commutator 10c, and the brush 12b
Since the current flows in the direction of the arrow in the order of, the rotor generates a rotational force in the direction of the arrow A according to Fleming's left-hand rule, and can start the rotor 5.

When the rotor is stopped in the state shown in FIG. 6B, when a voltage is applied, the brush 12a → the commutator 10a → the armature coil 11a → the armature coil 11
Since current flows in the direction of the arrow in the order of b → commutator 10b → brush 12b, the rotor generates a rotational force in the direction of arrow A according to Fleming's left-hand rule, and can start the rotor 5.

When the rotor is stopped in the state shown in FIG. 6C, when a voltage is applied, the brush 12a → the commutator 10d → the commutator 10b → the armature coil 1
1b → armature coil 11a → commutator 10a → brush 12b Since current flows in the direction of the arrow in the order of the arrows, the rotor generates a rotational force in the direction of the arrow A according to Fleming's left-hand rule, and can start the rotor 5. .

Further, when the rotor is stopped in the state shown in FIG. 6D, when a voltage is applied, the brush 12a → the commutator 10c → the commutator 10a → the armature coil 1
1a → armature coil 11b → commutator 10b → commutator 10d → brush 12b Since current flows in the direction of the arrow, the rotor generates a rotational force in the direction of arrow A according to Fleming's left-hand rule, and starts the rotor 5. be able to.

As described above, when the rotor 5 stops, the magnetic member 21 always stops at the center of any one of the four stators 4a to 4d. , 12b are always in contact with the commutator 10, and when a voltage is applied to the motor, a current flows through the armature coils 11a, 11b, and always acts on the armature coils 11a, 11b in the same direction due to the magnetic field of the stator. It is possible to avoid the existence of a starting dead center where the rotor cannot be started due to the generation of a force and the brush 11 is stopped in a state where the brush 11 is not in contact with the commutator 10.

FIG. 7 shows an example of a stopped state of a motor having no magnetic material. In the case of this motor, since a magnetic material for positioning is not provided on the rotor, the stop position of the rotor is not determined. The brush may stop halfway between the commutators. In this case, even when a voltage is applied to the motor, no current flows through the coil, so that no torque is generated and the rotor does not start. This state occurs at four places in the rotation direction of the rotor. Although the probability of occurrence of the starting dead center can be reduced by reducing the interval (slit width) between the commutator and the commutator, the response by the slit width cannot completely eliminate the starting dead center. If it is too small, the brush may short-circuit adjacent commutators.

FIGS. 8A to 8C show that the rotor rotates in the same direction regardless of the position of the rotor. In the state of FIG. 8A, power is supplied to the brushes 12a and 12b. Then, the brushes 12a are attached to the armature coils 11a and 11b.
The current flows in the direction of the arrow in the order of the commutator 10a, the armature coil 11a, the armature coil 11b, the commutator 10b, and the brush 12b. Rotate.

When the rotor rotates and reaches the state shown in FIG. 8B, the armature coils 11a and 11b are provided with brushes 12a.
→ commutator 10d → commutator 10b → armature coil 11b → armature coil 11a → commutator 10a
→ Since the current flows in the direction of the arrow in the order of the brush 12b,
The rotor generates a rotational force in the same direction (arrow A) as in FIG. 8A according to Fleming's left-hand rule.

When the rotor further rotates and reaches the state shown in FIG. 8C, the brush 12 is attached to the armature coils 11a and 11b.
a → commutator 10d → commutator 10b → armature coil 11a → armature coil 11b → commutator 10
Since current flows in the direction of the arrow in the order of c → commutator 10a → brush 12b, the rotor generates a rotational force in the same direction (arrow A) as in FIG. 8A (arrow A) according to Fleming's left-hand rule, and a voltage is applied to the brush. Is supplied, the armature coils 11a1a and 11b always have an arrow A with respect to the stator.
Since current flows so as to generate torque in the direction, rotation can be continued.

[0024]

According to the present invention, when the supply of voltage to the motor is stopped, the rotor always stops at the center of any one of the four stators, so that the commutator always contacts the brush. Motor (rotor)
When the voltage is applied again after the stop, the current can be reliably passed through the armature coil through the brush, and the magnetic field of the stator generates a force that always acts on the armature coils 11a and 11b in the same direction. Can be reliably started and rotated. Moreover, since a large weight member is provided as a whole, larger vibration can be generated while being small. In addition, the number of coils can be reduced to two, thereby reducing the manufacturing cost. In addition, there is no need to perform special processing on the coils, and the production yield can be increased, and the productivity can be improved. A high motor can be realized.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a flat type vibration motor according to the present invention.

FIG. 2 is a longitudinal sectional view of a main part of the flat type vibration motor.

FIGS. 3A to 3C are a plan view, a bottom view, and a cross-sectional view taken along line XX ′ of the rotor.

4A and 4B are a plan view and a bottom view of a commutator substrate.

5 (a) and 5 (b) are connection diagrams of a rotor, and development views of a flat vibration motor showing relative positions of a rotor, a commutator, a stator, a brush contact, and a magnetic body.

FIGS. 6A to 6D are explanatory diagrams of a state in which the rotor is started from a stopped state.

FIG. 7 is an explanatory diagram of a state in which a rotor without a magnetic body cannot be started due to a stopped position;

FIGS. 8A to 8C are explanatory diagrams showing directions of forces acting on an armature coil in relation to a direction of a current flowing through the armature coil and a magnetic field of a stator.

[Explanation of symbols]

 Reference Signs List 3 casing 4 stator 5 rotor 11 armature coil 20 weight member 21 magnetic body

Claims (1)

[Claims] 1. A flat type vibration motor having the following requirements. (A) A ring-shaped stator that is equally divided into four parts in the circumferential direction and that is alternately magnetized with N poles and S poles is disposed in a flat cylindrical casing. A rotatable, substantially semi-disc-shaped rotor is axially supported inside the rotor while being opposed to the stator, and two armature coils are symmetrically arranged on the rotor with respect to the support shaft of the rotor. (C) The rotor has a non-magnetic weight member provided in a substantially fan shape between the two armature coils, and the weight member has an axial magnetic material penetrating from one surface to the other surface. Is provided,
When the rotor is stopped, the magnetic body corresponds to the center of the magnetic pole of the stator. (D) The magnetic body is located near one of the armature coils at the circumferential end of the weight member. Be placed in