JP2003010783A - Linear vibration motor (2) - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear vibration motor with which no deformation of an elastic supporting member is generated, magnetic flux distribution in a gap section is not fluctuated and stable thrust is obtained. SOLUTION: The linear vibration motor is provided with a moving section 9 obtained by integrally forming a magnetic circuit section 8 in which a closed magnetic path is formed by opposingly arranging two magnetic poles and a holding member 5 which holds the section 8 and with a coil 4 which is wound on one of the magnetic poles. The section 9 and the coil 4 are arranged so that they are relatively displaced with each other.

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a linear vibration motor used for an incoming alarm in a pager or the like or a supply device in a part manufacturing process. 2. Description of the Related Art As a conventional linear vibration motor, for example, there is one shown in FIG. That is, in the XYZ orthogonal coordinate system, the permanent magnet 11 magnetized in the Z-axis direction has a pole-shaped movable magnetic yoke 2
1 and a non-magnetic holding member 51 is fixed to the back of the movable magnetic yoke 21 to form a movable portion. The movable section is attached to and supported by the tip of an elastic support member 61 extending in the Y-axis direction from both ends of a base 71 constituting a fixed section. A fixed magnetic yoke 31 is disposed on the base 71 so as to face the other magnetic pole surface of the permanent magnet 11 via the space G in the Y-axis direction, and is wound around the outer periphery of the fixed magnetic yoke. A coil 41 having a line segment in the Z-axis direction is fixed. The base 71, the fixed magnetic yoke 31, and the coil 41 form a fixed portion. [0004] With such a configuration, the permanent magnet 1
1. The movable magnetic yoke 21, the fixed magnetic yoke 31, and the coil 41 form a magnetic circuit in which magnetic flux circulates through the space G. Therefore, the movable portion composed of the permanent magnet 11, the movable magnetic yoke 21 and the holding member 51 is moved in the X-axis direction relative to the fixed portion composed of the coil 41, the fixed magnetic yoke 31 and the base 71. Displace. In this configuration, when an alternating current is supplied to the coil 41, the movable portion reciprocates in the X-axis direction due to Lorentz force generated between the permanent magnet 11 and the coil 41. [0007] In the case of the linear vibration motor as described above, the permanent magnet 11 and the movable magnetic yoke 2 are used.
1 and a fixed portion formed by the coil 41, the fixed magnetic yoke 31, and a base 71 provided with the two members. Because of the connection, the movable portion side is attracted to the fixed portion side by the Coulomb force of the permanent magnet, and compressive stress acts on the elastic support member, which may cause buckling. Further, since the relative position of the movable magnetic yoke with respect to the fixed magnetic yoke changes with the displacement of the permanent magnet, the distribution of the magnetic flux in the space G changes, and the thrust becomes unstable. An object of the present invention is to provide a linear vibration motor capable of solving the above-mentioned problems of the prior art, which does not cause deformation of the elastic support member, and has a magnetic flux distribution in the space. Is intended to provide a linear vibration motor capable of obtaining a stable thrust with no fluctuation. In order to achieve the above-mentioned object, a linear vibration motor according to the present invention comprises a magnetic circuit portion having two magnetic poles arranged opposite to each other to form a closed magnetic circuit, and a magnetic circuit portion. A movable section integrally formed with a holding member for holding; and a coil wound around the magnetic circuit section to excite the magnetic circuit section, wherein the movable section and the coil are relatively displaced. It is characterized by. Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 and FIG. 2 are an exploded perspective view and a perspective view of a main part showing a first embodiment of the present invention. In this case, in the XYZ rectangular coordinate system, Z
A permanent magnet 1 magnetized in the axial direction is connected to a gate-shaped first magnetic yoke 2 to form a first magnetic pole, and further becomes a second magnetic pole via a space G in the Z-axis direction. A magnetic yoke 3 is disposed to face the permanent magnet 1 and a first magnetic yoke 2
The respective ends of the second magnetic yoke 3 and the second magnetic yoke 3 are connected to each other to form an integrated magnetic circuit section 8. That is, the magnetic circuit 8 closes the magnetic flux from the permanent magnet 1 through the space G between the first magnetic yoke 2 as the first magnetic pole and the second magnetic yoke 3 as the second magnetic pole. Forming a road. The coil 4 is wound around the outer periphery of the second magnetic yoke 3 so that the line segment in the Y-axis direction is located in the space G, the magnetic circuit section 8 is movably arranged, and the base 7 Fixed to. The holding member 5 holds the magnetic circuit portion 8 to form a movable portion 9. One end of an elastic support member 6 extending along both side surfaces in the Y-axis direction of the magnetic circuit portion 8 is fixed to the base 7, and the other end of the elastic support member 6 is connected to the holding member 5. Have been. Therefore, the movable part 9 is suspended and supported by the base 7 via the elastic support member 6, and can be displaced in the X-axis direction with respect to the coil 4. When an alternating current is supplied to the coil 4, a Coulomb force is generated in the magnetic circuit section 8, and the movable section 9 reciprocates in the X-axis direction. In this case, the permanent magnet 1 is
Does not affect the elastic support member 6, there is no possibility that the elastic support member 6 will buckle. Further, since the permanent magnet 1, the first magnetic yoke 2, and the second magnetic yoke 3 constituting the magnetic circuit section 8 are integrally connected, the distribution shape of the magnetic flux does not change with the displacement, and the thrust is reduced. Stabilize. FIGS. 3 and 4 are plan views of a coil used in a second embodiment of the present invention, and FIGS.
FIG. 2 is an exploded view of the second embodiment and an assembly view with a part cut away. In FIG. 3, the coils 4a and 4b are respectively wound around axes parallel to the X axis, and are disposed adjacent to each other in the X axis direction. Further, the coil 4c is wound around an axis parallel to the Z axis, and the coils 4a and 4b are used for driving.
The coil 4c is used for feedback. In FIG. 4, the coil 4d is wound around an axis parallel to the Z axis and used for driving. In FIG. 5, permanent magnets 1a and 1b which are magnetized in the Z-axis direction in opposite directions to each other and are adjacent in the X-axis direction.
Is connected to one surface of the first magnetic yoke 2a to form a first magnetic pole. Further, the second magnetic yoke 3a is arranged so as to face the permanent magnets 1a and 1b in the Z-axis direction via the space G. To form a second magnetic pole, and the first magnetic yoke 2a and the second magnetic yoke 3a are connected to each other via a non-magnetic spacer 10 at their respective ends to form a first magnetic pole. And a second magnetic pole form a magnetic circuit 8a in which a closed magnetic path is formed. For example, the coils 4a and 4 shown in FIG.
The coil b is wound around the second magnetic yoke 3 while being spaced apart therefrom, and is disposed in the space G together with the coil 4c. The coils 4a, 4b, 4c are fixed to the base 7. The magnetic circuit portion 8a is held by the holding member 5,
Therefore, the movable portion 9 is suspended and supported by the distal end of the elastic support member 6 extending in the Y-axis direction of the base 7 so as to be capable of relative displacement in the X-axis direction with respect to the coils 4a, 4b, 4c. When an alternating current is supplied to the coils 4a and 4b, a Lorentz force directed in the same X-axis direction is generated in the space G with respect to the current flowing through the coils 4a and 4b. Reciprocating vibration. In this case, since the Coulomb force generated by the permanent magnets 1a and 1b on the second magnetic yoke 3a does not affect the elastic support member 6, there is no possibility that the elastic support member 6 will buckle. Further, since the permanent magnets 1a and 1b, the first magnetic yoke 2a, and the second magnetic yoke 3a that constitute the magnetic circuit 8a are integrally connected via the spacer 10, the distribution shape of the magnetic flux varies with the displacement. And thrust is stable. Here, similarly to the coils 4a and 4b shown in FIG. 3, if a coil wound like a coil 4d shown in FIG. 4 is used, a stable thrust can be similarly generated. When the magnetic circuit portion 8a is relatively displaced in the X-axis direction, the polarity of the magnetic flux linked to the coil 4c changes, so that an induced electromotive force is induced in the coil 4c. Therefore, if the output of the coil 4c is fed back to the oscillation circuit (not shown) and the output is again supplied to the coils 4a and 4b, the self-excited driving can be performed at the resonance frequency of the elastic support member 6. It is possible to reciprocate more efficiently with a large amplitude. FIG. 7 is an exploded perspective view and a perspective view of a main part showing a third embodiment of the present invention. In this case, a gate-shaped first magnetic yoke 2b is connected to one magnetic pole surface of the permanent magnet 1c magnetized in the Z-axis direction in the XYZ orthogonal coordinate system, and further to the other magnetic pole surface of the permanent magnet c. The second magnetic yoke 3b is disposed so as to face the Y axis direction via the space G, and the first magnetic yoke 2b
The respective ends of the first magnetic yoke 3b and the second magnetic yoke 3b are connected to each other to form an integrated magnetic circuit portion 8b. The coil 4d is wound around the second magnetic yoke 3b while being spaced apart from the second magnetic yoke 3b. The coil 4d is fixed to the base 7. The magnetic circuit section 8b forming the movable section 9 is connected to the tip of an elastic support member 6a connected to the base 7 and extending in the Y-axis direction via the holding member 5, and is connected to the coil 4d by X.
Suspended to allow relative displacement in the axial direction. In this example, similarly to the first embodiment, the Coulomb force generated by the permanent magnet 1c on the second magnetic yoke 3b does not affect the elastic support member 6a, so that the elastic support member 6a may be buckled. There is no. Further, since the permanent magnet 1c, the first magnetic yoke 2b, and the second magnetic yoke 3b constituting the magnetic circuit portion 8b are integrally connected, the distribution shape of the magnetic flux does not change with displacement, and the thrust is reduced. Stabilize. As described above, the permanent magnet, the first magnetic yoke, and the second magnetic yoke which constitute the magnetic circuit portion of the movable portion are integrally connected to form a closed magnetic circuit. So
The Coulomb force generated between the permanent magnet and the second magnetic yoke does not affect the elastic support member, and there is no possibility that the elastic support member will be buckled. Further, since there is no change in the distribution shape of the magnetic flux due to the displacement, the thrust is stabilized.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded view showing a main part of a first embodiment of the present invention. FIG. 2 is an assembly view showing the first embodiment of the present invention. FIG. 3 is a plan view showing an example of a coil used in a second embodiment of the present invention. FIG. 4 is a plan view showing another example of the coil used in the second embodiment of the present invention. FIG. 5 is an exploded view showing a main part of a second embodiment of the present invention. FIG. 6 is an assembly view showing a second embodiment of the present invention. FIG. 7 is an assembly view showing a third embodiment of the present invention. FIG. 8 is an explanatory diagram showing a conventional example. [Description of Signs] 1, 1a, 1b, 1c Permanent magnets 2, 2a, 2b First magnetic yokes 3, 3a, 3b Second magnetic yokes 4, 4a, 4b, 4c, 4d Coil 5 Holding unit 6, 6a Elastic support Member 7 Base 8, 8a, 8b Magnetic circuit section 9 Movable section G Space section

Claims (1)

Claims: 1. A movable section integrally formed with a magnetic circuit section having two magnetic poles arranged opposite to each other to form a closed magnetic circuit, and a holding member for holding the magnetic circuit section, and the magnetic circuit. Wound around
A linear vibration motor, comprising: a coil for exciting the magnetic circuit portion, wherein the movable portion and the coil are relatively displaced.