JPH09285070A - Vibration motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a vibration motor having a large vibration while a starting energy is suppressed. SOLUTION: A bearing 13 is fixed to the center of a frame 32. The outer circumference of the bearing 13 is fitted to the inner circumference of the attaching part 34 of a plate 33 above the frame 32. A weight 35 which is linked with an elastic member 37 is provided on the attaching part 34 so as to be moved freely. When the frame 32 is rotated, the plate 33 follows the rotation and the weight 35 which is placed near the bearing 13 at the starting is gradually moved toward the outer circumferential edge of the frame 32 by the centrifugal force which is increased by the acceleration of the plate 33 against the actuation force of the elastic member 37. As a result, the center of gravity of the plate 33 which is close to the shaft in a stationary state is moved toward the outer circumference of the plate 33 and an intense eccentricity is produced in the frame 32 and the plate 33 and a vibration motor vibrates violently. Moreover, as the center of gravity is close to the bearing 13 at the starting, a starting current may be small.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a vibration motor. More specifically, in a vibration motor having a rotating body rotatably supported, the center of gravity position is changed according to the rotation speed of the rotating body. The present invention relates to a vibration motor provided with a moving eccentric weight.

[0002]

2. Description of the Related Art In a notification device such as a pager or a mobile phone, in order to notify a calling signal to only the device owner surely and not to let anyone other than the device owner know, On the other hand, there is a notification device including a vibration motor that notifies by vibration.

The notification device is made small so as to be suitable for carrying, and the vibration motor is made small and lightweight so as to be suitable for this small structure. In addition, a power source for operation of this equipment is adopted that consumes less current and has high energy efficiency so that it can be used without being replenished for a long time.

As a conventional example of such a vibration motor, there is a shaft fixed type flat structure shown in FIG.

In FIG. 10, the vibration motor 1-1 is formed in the flat shape of a button type battery. The outer shape forming this flat shape is such that the opening of the cup-shaped case 5 is the bottom plate 6-1.
And covers the case 5 and the bottom plate 6-1 to form a closed casing. A through hole is provided in the case 5 and the bottom plate 6-1 at substantially the center thereof, and the shaft 12 is vertically arranged in the drawing.
For example, they are fixed by caulking. The shaft 12 has a bearing 13-1 integrally fixed to the eccentric rotating body 11.
Is inserted, and the eccentric rotor 3 is rotatable via washers 14 and 15 made of resin or the like for relaxing vertical sliding.

The rotating body 11 has a disk-shaped center portion as an axial core through which the shaft 12 is inserted, and is formed in a substantially semi-disk shape in which a tangent line contacting the peripheral surface of the rotating body 11 is moved toward the center and cut out. The center of gravity is deviated from the axis. Further, a plurality of air-core coils 10 are radially inserted from the axis of the rotating body 11, and a commutator 7 is formed on one surface in the axis direction to form the eccentric rotor 3.

A magnet 9 forming a field magnetic pole is fixedly arranged in an annular shape on the surface of the opposing bottom plate 6-1 of the air-core coil 10, and a brush 8 slidably contacting the commutator 7 is provided on the inner circumference of the magnet 9. It stands upright from the brush holder 4. An FPC 16 for supplying power to the brush holder is arranged between the brush holder 4 and the bottom plate 6-1 and a terminal 17 thereof projects outside the casing.

When a predetermined voltage is applied to the terminal 20 of the vibration motor 1-1 having such a structure, power is supplied from the brush 8 to the commutator 7 and further to the air-core coil 10 via the FPC, and the vibration motor 1-1 is arranged in an annular shape. The rotor 3 is driven and rotated by magnetic interaction with the magnet 9. At this time, since the center of the weight of the rotor 3 is deviated, the rotor 3 rotates while vibrating.

Another conventional example of such a vibration motor is shown in FIG. 11 of Japanese Patent Laid-Open No. 5-344699.
There is an axial rotation type cylindrical structure like this.

In FIG. 11, 21 of the vibration motor 1-2 is shown.
Is a bottomed cylindrical case, and a cylindrical magnet 29 is fixedly provided on the inner peripheral surface of the case to form a stator. Also,
A bearing 23 is provided at one end of the bottomed cylindrical case 21, and a bearing 23 ′ is provided at the case cover 24 at the other end.
A shaft 22 is rotatably supported between 3 '. A cylindrical winding 30 is provided on the opposite surface of the cylindrical magnet 29, the cylindrical winding 30 is fixed to the winding holder 25, and a driving current can be supplied via the brush 26 and the commutator 27. . The winding holder 25 is fixed to the shaft 22 integrally with the eccentric rotating body 28.

The eccentric rotating body 28 has a columnar shape, and as shown in the perspective view of FIG. 12, one of the eccentric rotating bodies 28 is a dense portion 18 and the other is a sparse portion 20 with a gap 19 at the axis 22a.
The center of gravity is set at a position displaced from the axis. Now, when the cylindrical winding 30 is energized via the brush 26 and the commutator 27, a magnetic interaction occurs between the cylindrical winding 30 and the cylindrical magnet 29, and the eccentric rotating body 28 fixed integrally with the shaft is provided. Vibrates toward the side of the cylinder.

In the above-mentioned conventional example, the fixed shaft type is used for the flat structure, and the axial rotation type is used for the cylindrical structure. However, by changing the shaft-related members, the flat structure can also be rotated. A mold having a cylindrical structure can be easily fixed to a shaft, so that the following description will be given on the assumption that all of them are included.

[0013]

However, in the above-mentioned conventional example, the center of gravity of the eccentric rotor is at a fixed position regardless of the rotation speed. On the other hand, the eccentric motor is small,
Moreover, large vibration is desired. In order to obtain a large vibration despite such a small size, it is necessary to increase the mass of the eccentric rotary member or rotate the eccentric rotary member at a high speed.
In order to increase the mass, it is necessary to manufacture the eccentric rotating body using a member having a large specific gravity, but such a member is expensive. Further, when the mass of the eccentric rotating body is large, it takes a long time to accelerate from the initial speed to the high speed. Due to the purpose of use of the eccentric motor, it is desirable that the acceleration time be short, and in order to shorten this acceleration time, it is necessary to increase the starting energy. The result is contrary to the specification and purpose of the notification device that you want to operate with. On the other hand, in the case of reducing the mass of the eccentric rotating body, the eccentric rotating body must be rotated at high speed in order to obtain the desired vibration, and in such a motor, the rotary sliding portion is severely worn and has a short life. .

Therefore, according to the present invention, when the motor is started, the driving is started with a small amount of starting energy, and the apparent center of gravity of the rotating body is moved to the outer peripheral portion of the rotating body in accordance with the high speed rotation, whereby the vibration of the peripheral portion of the rotating body is caused. It is intended to obtain the same frequency and amplitude as an eccentric motor in which the mass of the eccentric rotating body is increased by increasing the mass, and by adopting this structure, the current consumption is small and the prescribed frequency and amplitude can be obtained. A vibration motor can be provided.

[0015]

SUMMARY OF THE INVENTION Therefore, claim 1 of the present invention is provided.
The vibration motor of No. 1 includes a rotating body and an eccentric weight mounted on the rotating body and having a center of rotation different from the center of gravity. Vibration occurs when the eccentric weight rotates. It has a mounting portion mounted on the body, an elastic portion extending from the mounting portion, and a weight portion provided on one end side of the elastic portion, and the center of gravity of the eccentric weight corresponds to the rotation speed of the rotating body. Is characterized by moving.

In the vibrating motor according to the second aspect of the present invention, the position of the weight portion when rotating at a predetermined speed is located outside in the radial direction with respect to the position of the weight portion when the rotating body is stopped. It is characterized by doing.

A vibration motor according to a third aspect of the present invention is the vibration motor according to the first and second aspects, wherein the rotating body is an eccentric rotating body whose center of gravity is at a position different from the center of rotation. At the time of starting, the eccentric rotating body and the eccentric weight have the same center of gravity position, and as the eccentric rotating body and the weight rotate, a difference occurs in the center of gravity of the eccentric rotating body.

[0018]

1 is an exploded perspective view showing a vibration motor according to the present invention, which is in contrast to the conventional example shown in FIG. This vibration motor is a fixed shaft flat motor. Although the rotating body shown in FIG. 10 is divided into a frame and a plate, the actions related to the eccentricity of the frame and the plate, which are collectively called the rotating body, are the same. Members that operate in the same manner as in the conventional example are denoted by the same reference numerals, and the description that duplicates the description already given is omitted.

In FIG. 1A, the vibration motor 1 has a cup-shaped case 5 whose opening is covered with a bottom plate 6 to form a closed casing. A through hole 31 through which the shaft 12 passes is opened in the central portion of the case 5, while the shaft 12 is provided upright in the central portion of the bottom plate 6 toward the upper side in the drawing.
An annular magnet 9 is fixed to the outer side of 2. Further, between the shaft 12 and the magnet 9, a brush 8 concentrically arranged upward is placed in contact with a not-illustrated commutator. When the case 5 is covered on the bottom plate 6, the shaft 12 is fitted into the through hole 31 of the case 5, and
The case 5 is fixed to the outer edge surface of the bottom plate 6.

At a slight distance from the magnet 9,
A frame 32 in which the air-core coil 10 is embedded is arranged. A slide bearing 13 made of a sintered oil-impregnated alloy or the like is fixed to the center of the frame 32 so as to penetrate the shaft 12, and the lower end surface of the slide bearing in the figure contacts the bottom plate 6 to cause the magnet to move as described above. 9 and the air-core coil 10 face each other with a slight distance. That is, the plain bearing 13
In the thrust direction, the bottom plate 6 and the case 5 rotate while being held by a sliding washer such as Teflon (not shown) that assists in rotation. At this time, a drive current is supplied to the air-core coil 10 via the brush 8. The outer periphery of the slide bearing 13 is fitted to the inner periphery of the mounting portion 34 of the plate 33 on the upper portion of the frame 32, and when the frame 32 rotates due to the magnetic interaction between the magnet 9 and the air-core coil 10, the plate 33 also follows. It moves. The rotating direction of the rotating body can be set freely.

An elastic portion 37 made of phosphor bronze and other members and a movable weight portion 35 connected to the elastic portion 37 are provided on the outer periphery of the mounting portion 34. Also,
A protrusion 36 that restricts the movement of the weight portion 35 is planted near the outer periphery of the plate 33.

In this structure, as described above, when the frame 32 rotates, the plate 33 also follows as a rotating body, but when the frame 32 starts up or 4000RP.
In the state of low speed rotation of M or less, the weight portion 35 at the position shown in FIG. 1 receives a centrifugal force proportional to the square of the velocity as the plate 33 accelerates, and gradually resists the urging force of the elastic portion 37. It moves toward the outer peripheral edge, that is, the implanted protrusion 36. Suitably, 7000-8000RP
The biasing force of the elastic portion 37 is adjusted so as to contact the protrusion near M. As a result, the center of gravity of the plate, which was near the axis in the stopped state, moves toward the outer peripheral portion of the plate 33 with acceleration, and thus the frame 32 and the plate 3 are moved.
Apparently strong eccentricity occurs in No. 3. Therefore, the vibration motor vibrates violently. Moreover, since the center of gravity is near the bearing at the time of starting, the starting current becomes small.

Although the bearing 13 and the frame 32 are separately assembled in the above description, they may be integrally formed of a sintered alloy or the like, and the bearing portion formed of the sintered alloy or the like may be oiled. It can be preferably used by impregnating. In addition, as shown in FIG.
The projection 36 'for restricting the movement of the frame may be provided directly on the frame 32.

In FIG. 1, the frame 32 and the plate 33 are formed in a substantially semi-disk shape in which a central portion through which the shaft 12 is inserted is provided on the shaft center, and a tangential line whose peripheral surface is in contact with the peripheral surface is moved and cut in the central direction. Therefore, the center of weight is deviated from the above-mentioned axis, but the rotating body may be formed in a slightly disc shape other than the above figure.

FIG. 2 is a plan view showing another weight of the eccentric motor according to the present invention.

Various shapes can be selected as the shape of the weight. The weight 35-1 shown in FIG. 2 occupies 180 ° or more of the inner angle of a circle having the center of the mounting portion 34 as the midpoint, but in such a shape, the position of the center of gravity 38 at rest is mounted. Since it can be placed toward the center of the part 34,
Not only is it advantageous for the starting current, but the weight 3
The mass of 5-1 can be increased.

FIG. 3 is a diagram comparing the starting current and the rotation speed of the eccentric motor according to the present invention with those of the conventional eccentric motor. FIG. 3A shows a comparison of starting currents, and FIG. 3B shows a comparison of rotation speeds.

In FIG. 3 (a), the horizontal axis represents the time from the start, and the vertical axis represents the load current. Compared with the conventional example a,
The load current at the time of starting the eccentric motor b of the present invention shows a small value.

In FIG. 3 (b), the horizontal axis represents the time from the start, and the vertical axis represents the center of gravity. Compared to the conventional example a, the center of gravity of the eccentric motor b of the present invention at the time of starting is closer to the mounting portion, moves outward from the mounting portion with time, and exceeds the conventional example a after a certain time. , Further increase. Since the position of the center of gravity correlates with the vibration of the vibration motor, the amplitude at the time of starting is small, but it can be considered that the amplitude gradually becomes large.

FIG. 4 shows that the center of gravity of the rotating body and the center of gravity of the weight according to the present invention are at the same position at the time of starting, and the weight is displaced in the counter-rotational direction with respect to the rotating body as it rotates at high speed. It is a top view which shows the relationship between a weight and. FIG. 4A is a diagram showing the positional relationship between the rotating body and the weight in the starting state, and FIG. 4B is a diagram showing the positional relationship between the rotating body and the weight in the high-speed rotation state.

In FIG. 4, the rotating body 11 is an eccentric rotating body having the same shape as in FIG. 1, and the weight 35-2 rotates so that the center of gravity of the eccentric rotating body 11 shifts as it moves to high speed rotation. A biasing member 42 is installed from the locking portion 40 at a predetermined position of the body 11 toward the locking portion 41 at one end of the weight 35-2, while the outer circumference of the device portion 34 slides on the outer circumference of the device portion. Engage the ring 43 as much as possible
The elastic portion 37 is joined to the other end of the weight 35-2.

In this state, the center of gravity of the eccentric rotor 11 and the weight 35-2 are at the same position at the time of starting, and rotation is started with the above-mentioned starting current and amplitude. However, when rotating in the direction of the arrow, as the rotation speed increases, 35
The -2 weight moves from the ring portion 43 to the outer peripheral direction of the rotating body 11 by centrifugal force, and the eccentric rotating body 11 and the weight 3
A difference in inertia due to a difference in mass of 5-2 causes a difference in the center of gravity between the eccentric rotating body 11 and the weight 35-2. This means that there is a time difference with respect to the rotation, which results in two time difference amplitudes. And these two amplitudes resonate. At this time, the biasing member 42 vibrates in a complicated manner in association with the resonance, and this vibration also increases the resonance. Further, the elastic portion 37 also produces a subtle pulsation, which also increases the resonance in the same manner as described above.

FIG. 5 shows the vibration of the eccentric rotor and the weight 3
It is a figure which shows the vibration of 5-2, and the resonance which they make.
FIG. 5A is a diagram showing vibration of the eccentric rotating body.
5B is a diagram showing vibration of the weight, and FIG. 5C is a diagram showing resonance of the eccentric rotating body and the weight.

In FIG. 5, the center of gravity of the eccentric rotor and the weight are in the same position in the starting state, so the vibrations of both are the same, but the center of gravity shifts as the rotation speed increases, and due to the difference in mass, Two vibrations having a time difference t are generated, and at least a resonance vibration shown in FIG. 5C is generated, which is composed of the sum of the curves of FIG. 5A and the curve of FIG. 5B. Actually, since the biasing member 42 and the elastic portion 37 also vibrate as described above, further complicated vibration is caused.

FIG. 6 is a perspective view of an essential part when a weight is installed outside the motor case of the shaft rotation type eccentric motor instead of the embodiment shown in FIG. Members that operate in the same manner as in FIG. 1 are assigned the same reference numerals, and duplicate explanations are omitted.

In FIG. 6, 12-1 is a motor case 3.
It is a shaft as a rotating body with one end protruding from 9
Is a device unit attached to the shaft 12-1. Further, 35 is a weight portion, and the mounting portion 34 and the weight portion 35 are connected by an elastic portion 37. Also, 3
Reference numeral 6 is a protrusion for limiting the movement range of the weight portion 35. If the shaft 12-1 and the device unit 34 are fitted with each other in such a configuration, the weight 35 is rotated along with the rotation of the shaft 12-1.
Is rotated while moving in the outer peripheral direction of the motor case 39 by the centrifugal force, and the same effect as that of FIG. 1 can be obtained.

FIG. 7 is a diagram showing another mode of the embodiment described in FIG.

In FIG. 7, the weight 35-2 is composed of an annular deforming member, a part of which is thick. And
The weight 35-2 includes a rubber-like elastic body 37 from the mounting portion 34.
Connect -1. With the rotation of the rotating body, the weight 35-
2 is biased and the rubber-like elastic body 37-1 expands and contracts,
The same effect as that of the embodiment described in FIG. 6 can be obtained.

FIG. 8 is a diagram showing another mode of the embodiment described in FIG.

In FIG. 8, the weight 35-3 and the mounting portion 34 are connected by a helical spring 37-2. With the rotation of the weight 35-3, the spring 37-2 extends and the weight 35-3 moves toward the outer peripheral edge portion of the rotating body 11.
The same effect as that of the embodiment described in FIG. 6 can be obtained.

In the above embodiment, an example in which the eccentric weight is provided on the rotary shaft located substantially at the center of the vibration motor is shown, but the configuration as shown in FIG. 9 may be adopted. That is, a disk-shaped rotary plate 33-1 is fixedly mounted on one end of the rotary shaft, and the eccentric weight mounting portion 34-1 is mounted on the outer edge of the rotary plate 33-1 toward the center of rotation. Elastic part 37-3 that is twisted once in the middle and has a bend in the radial direction
Extend. An eccentric weight 35-4 is provided at the tip of the elastic portion 37-3 so that the center of rotation and the center of gravity substantially coincide with each other when the rotating body is not rotating. When the rotating body rotates, the eccentric weight 35-4 moves outward in the radial direction by the elasticity of the elastic portion 37-3, and the eccentricity increases.
With such a configuration, the same effect as that of the above embodiment can be obtained.

[0042]

In the vibrating motor according to the present invention, the weight whose center of gravity is changed depending on the rotational speed is provided separately from the rotating body through the elastic portion from the mounting portion, so that the motor is driven with a small amount of starting energy. Then, the apparent center of gravity of the rotating body can be moved to the outer peripheral portion of the rotating body in accordance with the high speed rotation. As a result, the vibration of the peripheral portion of the rotating body can be increased, and the vibration motor having a high frequency and a strong amplitude can be obtained, and its transmission function is increased when it is used as a notification device.

Further, the center of gravity of the eccentric rotor and the weight are placed at the same position at the time of starting, the rotation is started with a small starting current and amplitude, and as the speed becomes higher, the position of the center of gravity of the weight and the eccentric rotor becomes different. By doing so, two amplitudes having a time difference with respect to the rotation direction are generated, and these two amplitudes resonate. As a result, the vibration motor is small in size and can be driven with a small amount of electric power while obtaining a large amplitude.

[Brief description of drawings]

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

FIG. 2 is a plan view showing another weight of the eccentric motor according to the present invention.

FIG. 3 is a diagram comparing a starting current and a rotation speed of an eccentric motor according to the present invention with those of a conventional eccentric motor.

FIG. 4 is a diagram showing the relationship between the weight and the center of gravity of the rotating body and the center of gravity of the weight according to the present invention, which are shifted to the same position at the time of starting and in the rotation direction as the speed increases.

FIG. 5 is a diagram showing vibrations of an eccentric rotating body, vibrations of a weight, and resonances formed by the vibrations according to the present invention.

FIG. 6 is a perspective view of a main part when a weight is installed outside the motor case of the shaft rotation type eccentric motor according to the present invention.

FIG. 7 is a diagram showing another aspect of the embodiment according to the present invention.

FIG. 8 is a diagram showing another aspect of the embodiment according to the present invention.

FIG. 9 is a diagram showing another aspect of the embodiment according to the present invention.

FIG. 10 is a conventional example showing a shaft-fixed type vibration motor having a flat structure.

FIG. 11 is a conventional example showing a shaft-rotating cylindrical vibration motor.

12 is a perspective view showing an eccentric rotating body of the cylindrical vibration motor shown in FIG. 11. FIG.

[Explanation of symbols]

 5 Case 6 Bottom plate 9 Magnet 10 Air core coil 12 Shaft 13 Sliding bearing 32 Frame 33 Plate 34 Mounting part 35 Weight part 37 Elastic part 40 Locking part 41 Locking part 42 Energizing member

[Procedure amendment]

[Submission date] November 11, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0024

[Correction method] Change

[Correction contents]

In FIG. 1, the frame 32 and the plate 33 are formed in a substantially semi-disk shape in which a central portion through which the shaft 12 is inserted is provided on the shaft center, and a tangential line whose peripheral surface is in contact with the peripheral surface is moved and cut in the central direction. Therefore, the center of gravity is deviated from the axis, but the rotating body may be formed in a disc shape other than the above figure.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0031

[Correction method] Change

[Correction contents]

In FIG. 4, the rotating body has the same shape as in FIG.
The eccentric rotating body 11 has a weight 35-2 from the locking portion 40 at a predetermined position of the eccentric rotating body 11 so that the center of gravity of the weight 35-2 shifts as the center of gravity of the eccentric rotating body 11 moves to high speed. A biasing member 42 is installed toward the locking portion 41 at one end of 35-2, while a ring portion 43 is slidably engaged with the outer periphery of the device portion 34 on the outer periphery of the device portion 34. The elastic portion 37 is joined to the other end of the weight 35-2.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0032

[Correction method] Change

[Correction contents]

In this state, the center of gravity of the eccentric rotor 11 and the weight 35-2 are at the same position at the time of starting, and rotation is started with the above-mentioned starting current and amplitude. However, when rotating in the direction of the arrow, as the rotation speed increases, 35
-The 2 weight is the eccentric rotating body 1 from the ring portion 43 by the centrifugal force.
While moving in the 1 outer peripheral direction, a difference in the center of gravity between the eccentric rotating body 11 and the weight 35-2 occurs due to a difference in inertia due to a difference in mass between the eccentric rotating body 11 and the weight 35-2. This means that there is a time difference with respect to the rotation, which results in two time difference amplitudes. And this 2
The two amplitudes resonate. At this time, the biasing member 42 vibrates in a complicated manner in association with the resonance, and this vibration also increases the resonance. Further, the elastic portion 37 also produces a subtle pulsation, which also increases the resonance in the same manner as described above.

[Procedure amendment 4]

[Document name to be amended] Drawing

[Correction target item name] Fig. 6

[Correction method] Change

[Correction contents]

FIG. 6

Claims (3)

[Claims] 1. A vibration motor comprising a rotating body and an eccentric weight attached to the rotating body and having a center of rotation different from the center of gravity, wherein vibration is generated when the eccentric weight rotates. It has a mounting portion mounted on the body, an elastic portion extending from the mounting portion, and a weight portion provided on one end side of the elastic portion, and the center of gravity of the eccentric weight corresponds to the rotation speed of the rotating body. The vibration motor is characterized by moving the. 2. The position of the weight portion when rotating at a predetermined speed is located outside in the radial direction with respect to the position of the weight portion when the rotating body is stopped. Vibration motor described. 3. The vibration motor according to claim 1, wherein the rotating body is an eccentric rotating body having a center of gravity at a position different from a center of rotation, and the eccentric rotating body and the eccentric weight are provided at the time of starting. The vibration motor is characterized in that the center of gravity of the eccentric rotor and the weight of the eccentric rotor are different as the center of gravity of the eccentric rotor rotates at a higher speed.