JP2003010784A - Linear vibration motor (1) - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear vibration motor in which magnetic efficiency is made higher by reducing a magnetic gap, no attraction of a movable magnetic yoke caused by coulomb force is generated, deviation between the frequency of AC current being applied and the resonance frequency of an elastic supporting member is eliminated and thus high thrust is stably obtained. SOLUTION: The motor consists of a plurality of permanent magnets 1a and 1b and driving coils 4a and 4b. In an XYZ orthogonal coordinate system, the magnets are magnetized in a parallel direction with respect to the Y axis and along mutually reversed directions. The magnets are arranged adjacent to each other in the X axis direction and back surface magnetic pole sides thereof are connected with each other through a first magnetic yoke 2. The coils have coil segments extended along the Z axis direction and are arranged to oppose the surface side magnetic poles of the permanent magnets in the Y axis direction. Either one of the permanent magnet side and the driving coil side is reciprocatingly moved along the X axis direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear vibration motor used for an incoming call alarm in a pager or the like and a supply device in a component manufacturing process.

[0002]

2. Description of the Related Art Conventionally proposed linear vibration motors include those shown in FIG. That is, in the XYZ rectangular coordinate system, the arm 103 extending in the Y-axis direction from both ends and the center of the base portion extending in the X-axis direction.
a substantially E-shaped magnetic yoke 105 having a, 103b, 103c, and a coil 10 wound around an arm 103c.
4 and a fixed portion 108 composed of the magnetic yoke 105, and the magnetic yoke 105 is suspended and supported by the elastic support member 106 so as to be movable in the X-axis direction.
2a and 102b are vibrating masses 10 made of permanent magnets 101 each having a movable member 107 formed at the tip in the Y-axis direction.
9 and.

The permanent magnet 101 is formed by each arm 103.
a, 103b, 103c and the magnetic gap, the permanent magnet 101-the movable magnetic yoke 102a-the arm 103a-
Magnetic loop of arm 103c or permanent magnet 101-movable magnetic yoke 102b-arm 103b-arm 103
It is arranged so that a magnetic circuit of c forms a magnetic circuit.

When the coil 104 is energized, a magnetic flux is generated in the arms 103a and 103b of the magnetic yoke 105, which is attracted or repelled by the Coulomb force generated between the coil 103 and the permanent magnet 101.
It is displaced in the X-axis direction so as to approach either a or 103b. Therefore, when an alternating current having a frequency corresponding to the resonance frequency of the bending of the elastic support member 106 is applied to the coil 104, the permanent magnet 101 side reciprocally vibrates in the X-axis direction.

[0005]

However, in the above-mentioned linear vibration motor, since there are many magnetic gaps on the magnetic circuit and the permeance of the permanent magnets is reduced to lower the efficiency, a large thrust is generated in the vibrating mass. I can't. In addition, the movable magnetic yokes 102a and 102b
In order to displace the permanent magnet 101 attracted to one of the arms 103a or 103b to the other arm side by the Coulomb force via the coil, it is necessary to add an additional amount of electricity to the coil 104 in order to give a thrust force exceeding the attraction force. The vibration efficiency is poor.

When an open-loop alternating current is applied from an external power source to oscillate the vibrating mass 109, the current applied due to fluctuations in the alternating current frequency and changes in the elastic modulus of the elastic support member 106. And the resonance frequency of the elastic support member 106 deviate from each other, and a sufficient vibration amplitude cannot be obtained.

The object of the present invention has been made in view of such a conventional problem. The magnetic gap is reduced to improve the magnetic efficiency, and the Coulomb force does not attract the movable magnetic yoke. It is an object of the present invention to provide a linear vibration motor, and at the same time, to provide a linear vibration motor capable of stably obtaining a high thrust by eliminating a deviation between a frequency of an applied alternating current and a resonance frequency of an elastic supporting member.

[0008]

To achieve the above object, the linear vibration motor of the present invention is magnetized in the XYZ orthogonal coordinate system in directions opposite to each other in parallel with the Y axis and in the X axis direction. A plurality of permanent magnets, which are arranged adjacent to each other and whose back magnetic pole side is connected via the first magnetic yoke, and a coil wire segment extending in the Z-axis direction, are provided. Each of them is composed of a drive coil facing each other in the Y-axis direction, and reciprocates either the permanent magnet side or the drive coil side in the X-axis direction.

A preferred embodiment of the linear vibration motor of the present invention is characterized in that a second magnetic yoke is provided on the back side of the drive coil described in claim 1.

A preferred embodiment of the linear vibration motor according to the present invention is characterized in that the magnetic detecting means is arranged near the X-axis direction end of the magnetic pole of the permanent magnet described in claim 1.

A further preferred embodiment of the linear vibration motor is characterized in that a drive signal based on the output of the magnetic detection means is applied to the drive coil.

In a preferred embodiment of the linear vibration motor of the present invention, the magnetism detecting means is a Y magnet of the permanent magnet.
The detection coil is wound around an axis parallel to the axis.

In a preferred embodiment of the linear vibration motor of the present invention, the magnetism detecting means is the X of the permanent magnet.
It is characterized in that the detection coil is wound around an axis parallel to the X axis near the end in the axial direction.

[0014]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are a plan view and a perspective view showing a first embodiment of the present invention. That is, the permanent magnets 1a and 1b arranged so as to be adjacent to each other in the X-axis direction in the XYZ orthogonal coordinate system are magnetized in parallel with the Y-axis and in opposite directions to each other, and the rear magnetic pole side is X-axis.
The permanent magnets 1a and 1b are connected by the first magnetic yoke 2 extending in the axial direction to close the magnetic circuit on the back magnetic pole side.
Has a high permeance.

The permanent magnets 1a, 1b and the first magnetic yoke 2 are connected to a movable member 7 so that they can integrally move as an oscillating mass.

Y is applied to each of these permanent magnets 1a and 1b.
A second magnetic yoke 3 extending in the X-axis direction is arranged so as to oppose the axial direction to further enhance the permeance of the permanent magnets 1a and 1b. The drive coils 4a and 4b having coil wire segments extending in the Z-axis direction are formed so as to be wound around the second magnetic yoke 3, and are fixed to the fixing member 5 together with the second magnetic yoke 3. It

An elastic support member 6 holding a movable member 7 is connected to a fixed member 5 fixed to a vibrating member such as a pager (not shown) so that the movable member 7 can move in the X-axis direction. Suspended and supported.

The drive coil 4a is arranged in the magnetic field in the Y-axis direction by the permanent magnet 1a, and the other drive coil 4b is arranged in the magnetic field in the opposite direction by the permanent magnet 1b. When currents in mutually opposite directions are simultaneously supplied to the coils 4a and 4b, a Lorentz force is generated in the X-axis direction of the permanent magnets 1a and 1b, which acts as a thrust force to the permanent magnets 1a and 1b. The magnetic yoke 2 and the movable member 7 are displaced to the left and right in the X-axis direction.

The resonance frequency of the vibration of the elastic support member 6 in the X-axis direction is determined by the elastic modulus of the elastic support member 6 and the mass on the vibrating mass side connected to the tip. An alternating current having the same frequency as the resonance frequency is applied to the drive coils 4a and 4b.
, The vibrating mass efficiently vibrates in the X-axis direction.

In this embodiment, the fixing member 5
Is used as the fixed side and the movable member 7 is used as the working side. Conversely, it is also possible to use the movable member 7 side as the fixed side and the fixed member 5 side as the movable side to form a linear vibration motor. . Further, even if the second magnetic yoke 3 is omitted, the thrust can be obtained sufficiently efficiently.

FIGS. 3 and 4 are a plan view and a perspective view showing a second embodiment of the present invention. Permanent magnets 1 arranged adjacent to each other in the X-axis direction in the XYZ orthogonal coordinate system
a and 1b are magnetized in parallel with the Y axis and in opposite directions,
Each back magnetic pole side is connected by a first magnetic yoke 2 extending in the X-axis direction, and the permanent magnets 1a and 1b and the first magnetic yoke 2 are connected to a movable member 7 and integrated as a vibrating mass. Exercise is possible.

Y is applied to each of the permanent magnets 1a and 1b.
The second magnetic yoke 3 extending in the X-axis direction is arranged so as to face the axial direction, and the drive coils 4a and 4b having coil wire segments extending in the Z-axis direction are, for example, the second magnetic yoke. 3 is formed so as to be wound around 3, and the permanent magnet 1 is provided near the boundary between the permanent magnet 1a and the permanent magnet 1b.
As the magnetic detection means S, a detection coil 10 wound around an axis parallel to the Y axis is provided so as to face each of a and 1b. The drive coils 4a and 4b and the detection coil 10 are fixed together with the second magnetic yoke 3 and the fixing member 5.
Fixed to.

An elastic support member 6 for holding a movable member 7 is connected to the fixed member 5 fixed to the vibrated member,
The movable member 7 is suspended and supported so as to be movable in the X-axis direction.

The drive coil 4a is disposed in the magnetic field of the permanent magnet 1a in the Y-axis direction, and the drive coil 4b is arranged in the permanent magnet 1a.
The magnetic field of the permanent magnet 1a is arranged in a direction opposite to the magnetic field of the permanent magnet 1a by b, and when currents in the opposite directions are simultaneously supplied to the drive coils 4a and 4b, respectively.
A Lorentz force is generated in the X-axis direction of a and 1b, and this becomes a thrust force, and the permanent magnets 1a and 1b move together with the first magnetic yoke 2 and the movable member 7 at a speed corresponding to the resonance frequency of the elastic support member 6. The elastic support member 6 is vibrated by being displaced to the left and right in the X-axis direction.

With the displacement of the permanent magnets 1a, 1b in the X-axis direction, the permanent magnets 1a, 1 interlink with the detection coil 10.
The direction of the magnetic flux from b changes, and an induced electromotive force having a frequency corresponding to the resonance frequency of the elastic support member 6 is output to the detection coil 10.

The output of the detection coil 10 serving as the magnetic detection means S is supplied to the detection circuit C of the oscillation circuit as shown in FIG. 5 for phase adjustment, and further supplied to the drive circuit D for amplification, and the drive coil 4a. , 4b are energized. Although the driving coils 4a and 4b are connected in series here, they may be connected in parallel.

When a current is supplied from the drive circuit D to the drive coils 4a, 4b, a thrust force is applied to the permanent magnets 1a, 1b in a direction to accelerate the vibration of the elastic support member 6 in the X-axis direction, and this operation is performed. Is repeated, the vibration level of the vibrating mass is grown, and the vibration with a large amplitude is continued so that the self-excited vibration can be maintained.

In the present description, the detection coil 10 is illustrated as the magnetic detection means S, but the present invention is not limited to this, and an MR element, a Hall element or the like may be used.

FIG. 6 shows a modification of the second embodiment, in which the detection coil 10a is wound around an axis parallel to the Y-axis near the ends of the permanent magnet 1a and the permanent magnet 1b in the X-axis direction. , 10b are provided, but an induced electromotive force having a frequency corresponding to the resonance frequency of the elastic support member 6 is output to the detection coils 10a and 10b, as in the second embodiment, and the vibration mass X. Since the displacement in the axial direction can be detected, the self-excited vibration can be maintained by connecting the oscillation circuit as shown in FIG.

7 and 8 are a plan view and a perspective view showing a third embodiment of the present invention. Permanent magnets 1a, 1c and 1b, which are sequentially arranged so as to be adjacent to each other in the X-axis direction in the XYZ orthogonal coordinate system, are magnetized so as to be parallel to the Y-axis and alternately in opposite directions, and each back magnetic pole side is X-axis. Connected by a first magnetic yoke 2 extending in the axial direction,
The permanent magnets 1a, 1c, 1b and the first magnetic yoke 2 are connected to the movable member 7 so that they can integrally move as an oscillating mass.

A second magnetic yoke 3 extending in the X-axis direction is arranged so as to face the Y-axis direction on each of the permanent magnets 1a, 1c, 1b, and a coil wire segment extending in the Z-axis direction is provided. Drive coils 4a, 4b having a permanent magnet 1a,
1b is formed so as to be wound around the second magnetic yoke 3, and the detection coil 11 is provided around the second magnetic yoke 3 as the magnetic detection means S so as to be opposed to the permanent magnet 1c. It is wound.

In the detection coil 11, the magnetic flux generated between the surface magnetic poles of the permanent magnet 1a and the permanent magnet 1c and the magnetic flux generated between the surface magnetic poles of the permanent magnet 1b and the permanent magnet 1c, respectively. Are interlinked, and changes in magnetic flux can be detected efficiently.

The drive coils 4a and 4b and the detection coil 11 are fixed to the fixing member 5 together with the second magnetic yoke 3.

An elastic support member 6 for holding the movable member 7 is connected to the fixed member 5 fixed to the member to be vibrated,
The movable member 7 is suspended and supported so as to be movable in the X-axis direction.

The drive coil 4a is arranged in a magnetic field in the Y-axis direction by the permanent magnet 1a, and the drive coil 4b is arranged in a magnetic field in the opposite direction by the permanent magnet 1b. When currents in the same direction are simultaneously supplied to each of 4a and 4b, X of the permanent magnets 1a and 1b is increased.
A Lorentz force is generated in the axial direction, and this becomes a thrust force, and the permanent magnets 1a and 1b together with the other permanent magnet 1c, the first magnetic yoke 2, the movable member 7, and the elastic support member 6 are provided.
The movable member 7 vibrates at the same frequency as the resonance frequency of the elastic support member 6 because it is displaced to the left and right in the X-axis direction at a speed corresponding to the resonance frequency of.

With the displacement of the permanent magnets 1a, 1c, 1b in the X-axis direction, the permanent magnet 1 interlinks with the detection coil 11.
The direction of the magnetic flux due to a, 1c, and 1b changes, and an induced electromotive force having a frequency corresponding to the resonance frequency of the elastic support member 6 is output to the detection coil 11.

[0038]

As described above, according to the present invention, since the magnetic gap can be reduced and the permeance of the permanent magnet can be increased, a large thrust can be applied to the vibrating mass. Further, the magnetic yoke does not stick to the other magnetic yoke due to the Coulomb force.

Further, since the closed loop oscillation circuit can be constructed, the alternating current can be efficiently applied, and the driving can be performed at the frequency following the resonance frequency change due to the change of the elastic modulus of the elastic support member and the sufficient vibration amplitude can be obtained. Obtained stably.

[Brief description of drawings]

FIG. 1 is a plan view showing a first embodiment of the present invention.

FIG. 2 is a perspective view showing a first embodiment of the present invention.

FIG. 3 is a plan view showing a second embodiment of the present invention.

FIG. 4 is a perspective view showing a second embodiment of the present invention.

FIG. 5 is a circuit block diagram showing a second embodiment of the present invention.

FIG. 6 is a plan view showing a modified example of the second embodiment of the present invention.

FIG. 7 is a plan view showing a third embodiment of the present invention.

FIG. 8 is a perspective view showing a third embodiment of the present invention.

FIG. 9 is a diagram showing a conventional example.

[Explanation of symbols]

1a, 1b, 1c Permanent magnet 2 First magnetic yoke 3 Second magnetic yoke 4a, 4b drive coil 5 fixing members 6 Elastic support member 7 Movable member 10, 10a, 10b, 11 detection coil S Magnetic detection element C detection circuit D drive circuit

Claims (6)

[Claims] 1. In an XYZ orthogonal coordinate system, the magnets are magnetized in parallel with the Y-axis and in mutually opposite directions, and adjacent to each other in the X-axis direction on the back magnetic pole side via a first magnetic yoke. A plurality of permanent magnets and a coil wire segment extending in the Z-axis direction, and a drive coil facing each of the magnetic poles on the surface side of the permanent magnet in the Y-axis direction. A linear vibration motor characterized by reciprocating one of the coil sides in the X-axis direction. 2. The linear vibration motor according to claim 1, wherein a second magnetic yoke is provided on the back side of the drive coil. 3. The linear vibration motor according to claim 1, wherein the magnetic detection means is arranged in the vicinity of the X-axis direction end of the magnetic pole of the permanent magnet. 4. The linear vibration motor according to claim 3, wherein a drive signal based on the output of the magnetic detection means is applied to the drive coil. 5. The linear vibration according to claim 3, wherein the magnetic detection means is a detection coil wound around an axis parallel to the Y axis of the plurality of permanent magnets. motor. 6. The linear vibration according to claim 3, wherein the magnetic detection means is a detection coil wound around an axis parallel to the X axis of the plurality of permanent magnets. motor.