JP2000253640A - Linear vibration motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve efficiency of a motor, reduce heat generation, restrain demagnetization and improve reliability, by reducing eddy current loss in a movable magnet body by using an insulating thin plate. SOLUTION: A linear vibration motor 10 is provided with a stator core 18 constituted of a first magnetic material core 12 having a coil 14 and a second magnetic material core 16 which is arranged facing the core 12 interposing a magnetic air gap 20, and a movable magnet body 22 which is arranged in the magnetic air gap 20 and capable of displacement in the axial direction. The movable magnet body 22 consists of permanent magnets 24, 26 divided into a plurality of segments and insulating thin plates 28 arranged between the divided magnets.

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, and more particularly, to a linear vibration motor having a movable body disposed in a magnetic gap formed in a stator core and displaced in an axial direction.

[0002]

2. Description of the Related Art A conventional linear vibration motor is, for example, shown in FIG.
FIG. The linear vibration motor 1 includes a first magnetic core 2 having a substantially E-shaped cross section, a coil 3 mounted on a center yoke 2 a of the first magnetic core 2, and an open end side of the first magnetic core 2. And a flat second magnetic core 5 disposed opposite to the first magnetic core 2 with the movable magnet 4 interposed therebetween. The movable magnet 4 is configured by joining two permanent magnets 4a and 4b magnetized in a direction indicated by an arrow in the drawing.
The second magnetic core 5 forms a stator core 6 together with the first magnetic core 2.

In the linear vibration motor 1 described above, a magnetic flux is generated by passing a current through the coil 3, and the magnetic flux flows through a magnetic path formed by the first magnetic core 2 and the second magnetic core 5. . The direction of the magnetic flux flowing through the magnetic path is changed by changing the direction of the current flowing through the coil 3, that is, by flowing the alternating current through the coil 3. By changing the direction of the magnetic flux flowing through the magnetic path with the alternating current, the movable magnet 4 continuously moves in the left-right direction. As a result, the movable magnet 4 reciprocates, and the reciprocating compressor is driven by transmitting the reciprocating force to, for example, a piston.

[0004]

In the linear vibration motor configured as described above, an eddy current is generated in a direction perpendicular to the plane of the drawing. Then, the eddy current causes a loss in the first magnetic core, the movable magnet, and the second magnetic core, thereby reducing the efficiency of the motor.

[0005] By the way, measures are taken to cut off eddy currents in the first magnetic core and the second character magnetic core constituting the stator core, but special measures are taken for the movable magnet 4. At present it has not been taken.

That is, since the movable magnet 4 is formed by contacting two permanent magnets 4a and 4b having different polarities, an eddy current is generated so as to straddle adjacent magnets. There is a problem in that the loss due to the eddy current lowers the motor efficiency, and the heat generated by the magnet causes demagnetization to lower reliability.

SUMMARY OF THE INVENTION Therefore, a main object of the present invention is to provide a highly reliable and efficient linear vibration motor with reduced demagnetization while reducing eddy current loss generated in a magnet.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a linear vibration motor having a movable magnet body disposed in a magnetic gap of a stator iron core having a coil and capable of being displaced in an axial direction. A linear vibration motor including a divided permanent magnet and insulating means provided between the magnets.

Further, the present invention relates to a linear vibration motor having a movable iron core body which is disposed in a magnetic gap and is capable of being displaced in an axial direction, wherein the permanent magnet is provided with a permanent magnet of a stator iron core having a coil. The linear vibration motor is characterized in that it includes an insulating means divided between the magnets and provided between the magnets.

[0010]

The movable magnets arranged in the magnetic gap formed in the stator core are insulated from each other by the permanent magnet divided into a plurality of parts and the insulating means provided between the magnets.
Eddy currents are blocked by this insulating means. In addition, even when the movable core is disposed in the magnetic gap where the permanent magnet of the stator core is mounted, the permanent magnet can be divided and the eddy current of the permanent magnet can be cut off by the insulating means provided between the magnets.

[0011]

According to the present invention, in a linear vibration motor, iron loss due to eddy current generated by a permanent magnet can be reduced, and the efficiency of the motor is improved. In addition, heat generation of the magnet can be reduced, demagnetization hardly occurs, and reliability is improved.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment according to the present invention will be described with reference to FIGS.

A movable magnet (MM) type near vibration motor 10 according to an embodiment of the present invention shown in FIG. 1 has a first magnetic core 12 having an E-shaped cross section, and a center of the first magnetic core 12. A stator core 18 composed of a second magnetic core 16 having an I-shaped cross-section, which is opposed to the coil 14 mounted on the yoke 12a and the open end of the first magnetic core 12 with a space therebetween; A movable magnet body is disposed in a magnetic gap formed by the first magnetic core and the second magnetic core and is displaceable in the axial direction.

The movable magnet body 22 includes four divided permanent magnets 24, 24 and 26, 26, and a thin insulating material is provided between the permanent magnets 24 and 24, 24 and 26 and 26 and 26. Are provided to provide a thin insulation between the magnets. The permanent magnets 24, 24 are magnetized in the same direction, and the permanent magnets 26, 26 are magnetized and arranged in the opposite direction to the permanent magnets 24, 24. When the permanent magnets are insulated from each other by the thin insulating material 28, for example, the permanent magnets 24 and 26 may be covered with an insulating film to form the movable magnet body 22. Furthermore, a similar effect can be obtained by forming a coating film (for example, epoxy spray coating or the like) formed by coating an insulating material on the adjacent surface or the entire surface of the magnet as the insulating material 28.

In the configuration described above, when a current is applied to the coil 14 in the direction shown in the figure, the stator core 18 composed of the first magnetic core 12 and the second magnetic core 16 The magnetic flux flows, and the magnetic poles of the first magnetic core 12 become SNS poles as shown. On the other hand, the movable magnet body 2
Since the four permanent magnets 24 and 26 constituting the magnet 2 are magnetized as shown in the drawing, the movable magnet body 22 moves rightward by receiving a thrust in a direction indicated by an arrow by a repulsive force and an attractive force. . When the direction of the current flowing through the coil 14 is reversed, the flow of the magnetic flux is in the direction indicated by the dotted line in the drawing, and the magnetic pole of the first magnetic core 12 is the N-S-N pole, contrary to the drawing. As a result, the repulsive force and the attractive force acting on the movable magnet body 22 are reversed, and the movable magnet body 22 moves leftward due to the thrust in the direction opposite to the solid line arrow in the drawing.

Therefore, by supplying an alternating current to the coil 14, the movable magnet body 22 reciprocates continuously. The movable magnet body 22 is cut off the eddy current by the divided permanent magnets 24 and 26 and the insulating material 28 provided between the magnets, so that the iron loss due to the eddy current of the movable magnet body 22 is reduced. In addition, since heat generation is suppressed, demagnetization does not occur, reliability is improved, and an efficient linear vibration motor can be provided.

The other modification shown in FIG. 2 is different from the embodiment of FIG. 1 only in the configuration of the movable magnet body 22.
Since other configurations are the same, the same reference numerals are given and the description thereof is omitted. That is, the movable magnet body 22 includes four divided permanent magnets 24, 24 and 26, 26 and these permanent magnets 24, 24, 24, 26, and 2
Electrical insulation members 28 are provided between 6 and 26 to insulate the magnets from each other, and the permanent magnets 24 and 26 and the insulation member 28 are integrally held by an insulation holding frame 30. The insulating holding frame 30 may be formed of, for example, a synthetic resin material, or may be formed by forming an insulating film on the surface of a metal frame. The operation in this case is the same as that of the embodiment shown in FIG. 1, and a description thereof will be omitted.

Next, a movable iron core (MI) type linear vibration motor 10 according to another embodiment of the present invention will be described with reference to FIG. The components corresponding to the embodiment of FIG. 1 will be described with the same reference numerals.

The linear vibration motor 10 is arranged in a stator core 18 having a C-shaped cross section, a coil 14 disposed in a slot of the stator core 18, and a magnetic gap 20 on the open end side of the stator core 18. And a permanent magnet 24, 26 mounted on the opposing surface of the stator core 18 forming the magnetic gap 20. And
Each of the permanent magnets 24 and 26 is divided into magnets 24a and 24b and magnets 26a and 26b, respectively, and the plate-like insulating materials 28 are provided between the divided magnets to be insulated from each other. Further, each pair of divided magnets 24a and 24b and magnets 26a and 26b are magnetized and arranged in opposite directions. Further, as another modified example, the same effect can be obtained by covering each of the divided magnets with an insulating film (not shown). The movable iron core 32 is formed by laminating magnetic steel plates of a predetermined shape in the axial direction.

The operation of this embodiment will be described.
4 to change the direction of the current flowing through the stator core 18
The direction of the magnetic flux flowing through the magnetic path formed by is changed to move the movable iron core body 32 left and right. That is, when a current is applied to the coil 14, the magnetic pole at the open end of the stator core 18 becomes an NS pole as shown in the figure, and the magnetic pole is mounted on the facing surface of the magnetic gap 20 in which the movable core 32 is arranged. Since the pair of magnets 24a and 24b and the other pair of magnets 26a and 26b are magnetized in the directions of the arrows, the magnetic flux flowing through the stator core 18 increases the magnetic flux of the right magnets 24a and 26a, and The magnetic flux of the magnets 24b and 26b is weakened. As a result, the movable iron core 32 moves rightward in response to the thrust in the direction in which the magnetic flux is strengthened, that is, the direction indicated by the solid line arrow.

When the direction of the current flowing through the coil 14 is changed, the magnetic pole at the open end of the stator
The direction of the magnetic flux flowing through the stator core 18 changes by reversing the poles. As a result, the magnetic flux of the right magnets 24a and 26a is weakened, and the magnetic flux of the left magnets 24b and 26b is strengthened, and the movable core 32 moves in the direction in which the magnetic flux is strengthened, that is, in the left direction.

Accordingly, by supplying an alternating current to the coil 14, the movable core 32 continuously reciprocates,
If a piston or the like is connected to the movable iron core 32, for example, a compressor for air or refrigerant can be driven. Also in this embodiment, since the permanent magnets 24 and 26 are divided and the divided magnets are insulated by an insulating material, the eddy current is cut off.

FIG. 4 is a modification of the MI type linear vibration motor 10 showing another embodiment according to the present invention. This linear vibration motor 10 has a coil 14 in a slot and permanent magnets 24 and 26 at both ends on the open side.
1st magnetic core 1 with a substantially U-shaped cross section
2. A second magnetic core having a substantially I-shaped cross section in which the permanent magnets 24 and 26 are mounted oppositely to the open side of the first magnetic core 12 and opposed to the permanent magnets 24 and 26, respectively. 16, the first magnetic core 12 and the second
A movable core body 32 that is disposed in the magnetic gap 20 of the stator core 18 formed by the magnetic core 16 and is displaced in the axial direction.
It is composed of

Each of the permanent magnets 24 and 26 is divided into a pair of magnets 24a and 24b and a pair of magnets 26a and 26b, respectively.
An insulating material 28 is provided between the magnets a and 26b to electrically insulate the magnets from each other.

The pair of magnets 24a and 24b and the magnets 26a and 26b are magnetized and arranged in the direction shown by the arrow in the figure. The movable core body 32 includes two laminated cores 36 connected at intervals by a shaft 34, and each laminated core 36 is provided with a permanent magnet 2 disposed opposite to each other.
4 and 24 and fixed to the shaft 34 so as to be located in a gap surrounded by the permanent magnet 26.

The MI type linear vibration motor 10 of this modified example
3 is the same as that of the previous embodiment shown in FIG. 3, and the detailed description is omitted. However, when a current is applied to the coil 14 in the illustrated state, the magnetic poles at both ends on the open side of the first magnetic core 12 become N−. The magnetic flux generated by the current according to the direction of the current strengthens the magnets 24a and 24b adjacent to the permanent magnets 24 and 26 and the magnets 24b and 26a of the magnets 26a and 26b, and the other magnet 24a. And 26b
The two cores 3 on the side where the magnetic flux is
6 moves, and the movable core 32 moves rightward. When the direction of the current flowing through the coil 14 is reversed, the magnetic poles at both ends on the open side of the first magnetic core 12 are reversed from the S-N pole opposite to the illustration, and the direction of the magnetic flux flowing through the magnetic path is also reversed. Therefore, the movable iron core 32 moves to the left.
Therefore, when an alternating current is applied to the coil 14, the movable core 32 continuously reciprocates. If a piston is connected to the shaft 34 of the movable core 32, the reciprocating compressor is driven.

FIG. 5 shows an MI type linear vibration motor 1.
Another embodiment of zero is shown. In this motor 10, a stator core 18 is formed in a cylindrical shape, and four yoke 1
8a, 18b, 18c and 18d are provided, the coil 14 is wound around each yoke, and a permanent magnet 24 having an arc-shaped cross section is fixed to the end face of each yoke as a stator magnet using an adhesive. The internal space 2 of the stator core 18
At 0, a columnar movable core body 32 having a shaft portion inserted at the center is disposed so as to be displaceable in the axial direction. Each of the permanent magnets 24 is divided into two magnets 24a and 24b as in the previous embodiments, and an insulating material 28 is provided between the magnets to electrically insulate the magnets from each other. Also in this case, instead of the insulating material 28, the magnets 24a and 24b may be covered with an insulating film to insulate the magnets from each other.

The operation in this embodiment is the same as that described above. Basically, when an alternating current is applied to the coil 14, the direction and strength of the magnetic flux alternately change, and the movable magnet 32 In the illustration shown in FIG. 5 (b), it reciprocates in the left-right direction.

FIG. 6 shows an MM type linear vibration motor 10.
In comparison with the embodiment shown in FIG. 1, the second magnetic core 16 having the I-shaped cross section that forms the stator core 18 is fixed to the movable magnet 22 to form an integral movable portion, and the coil 1
4 reciprocally moves left and right with respect to the first magnetic core 12 having an E-shaped cross section around which the magnetic core 4 is wound. Other configurations are substantially the same as those of the embodiment of FIG. Further, the operation principle is the same, and the description is omitted.

[Brief description of the drawings]

FIG. 1 is an illustrative view schematically showing an MM type linear vibration motor according to an embodiment of the present invention;

FIG. 2 is an illustrative view showing a schematic configuration of a modification of FIG. 1;

FIG. 3 is an illustrative view schematically showing an MI linear vibration motor according to another embodiment;

FIG. 4 is an illustrative view of another embodiment corresponding to FIG. 3;

FIGS. 5 (a) and (b) show still another embodiment of M
It is a top view of an I type linear vibration motor, and the principal part sectional view.

FIG. 6 is an illustrative view of a modified example of the MM type linear vibration motor shown in FIG. 1;

FIG. 7 is an illustrative view of a conventional example corresponding to FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Linear vibration motor 12 ... 1st magnetic body core 14 ... Coil 16 ... 2nd magnetic body core 18 ... Stator core 20 ... Magnetic gap 22 ... Movable magnet body 24, 26 ... Permanent magnet 28 ... Insulation material 30 ... Insulation holding Frame 32: movable iron core 36: laminated iron core

Claims (10)

[Claims] 1. A linear vibration motor including a movable magnet body disposed in a magnetic gap of a stator core having a coil and capable of being displaced in an axial direction, wherein the movable magnet body is divided into a plurality of permanent magnets, and A linear vibration motor comprising insulating means provided between permanent magnets. 2. A stator according to claim 1, wherein said stator core has a coil.
The magnetic core and the first magnetic core include a second magnetic core opposed via the magnetic gap, and the second magnetic core is configured to be movable integrally with the movable magnet. The linear vibration motor according to claim 1, characterized in that: 3. The linear vibration motor according to claim 1, wherein said insulating means includes an insulating thin plate or an insulating coating film. 4. The linear vibration motor according to claim 1, wherein said insulating means includes an insulating film covering each of said permanent magnets. 5. The linear vibration motor according to claim 1, wherein said plurality of permanent magnets are arranged such that adjacent magnets have opposite polarities. 6. The linear vibration motor according to claim 1, wherein said permanent magnet and said insulating means are held by a frame. 7. The linear vibration motor according to claim 6, wherein said frame is formed of an insulating material or is subjected to an insulating process. 8. A linear vibration motor having a movable iron core disposed in a magnetic gap and having an axially displaceable magnetic core and a stator core having a permanent magnet having a coil, wherein the permanent magnet is divided into a plurality of parts and divided. A linear vibration motor, characterized by including an insulating means provided between the magnets provided. 9. The linear vibration motor according to claim 8, wherein said insulating means includes an insulating thin plate or an insulating coating film. 10. The linear vibration motor according to claim 8, wherein said insulating means includes an insulating film covering each of said divided magnets.