JP7371926B2 - linear vibration motor - Google Patents

Description

The present invention relates to a linear vibration motor that linearly vibrates a movable element by magnetically driving it and outputs the vibration.

The above-mentioned linear vibration motor is installed in, for example, a mobile terminal device to notify the user of an incoming call, an operation input, etc. by vibration. Those disclosed in Documents 1 to 4 are known.

The linear vibration motor described in Patent Document 1 includes a disk-shaped fixed body 2, a movable body (movable element) 6 housed in the fixed body 2, and a fixed body 2 connected to the fixed body 2 and the movable body 6. The fixed body 2 and the movable body 6 are provided with a spring member (mechanical spring) 8 that supports the movable body 6 so as to be movable in the axial direction, and a magnetic drive mechanism 5 that drives the movable body 6 in the axial direction. By providing the gel-like damper member 9 disposed between them, resonance of the movable body can be effectively suppressed even when the spring member is connected to the movable body.

The linear vibration motor (linear actuator) described in Patent Document 2 includes a rectangular parallelepiped housing 220, a shaft 320 disposed inside the housing 220 and connected to both longitudinal ends of the housing 220, and a shaft 320 movably engaged with the shaft 320. combined masses (mover) 310, 330, a spring (mechanical spring) 510 that surrounds a portion of the shaft 320 and prevents the masses 310, 330 from contacting the housing 220, the shaft 320 and the mass 310, 330, and an electromagnetic structure 300 that applies a driving force to the masses 310, 330 so as to move the masses 310, 330 from the first position to the second position; Producing a tactile output upon movement from one position to a second position allows the mass to be moved in two directions with a relatively compact configuration.

The linear vibration motor (linear actuator) described in Patent Document 3 includes a bar-shaped movable element 4 having at least one permanent magnet 3a, 3b, 3c whose N pole and S pole are magnetized in the axial direction, and the movable element 4. It includes a cylindrical stator 2 in which a first coil 1a and a second coil 1b surrounding it are arranged in the axial direction, and the phase of the thrust generated in the first coil 1a and the thrust generated in the second coil 1b is adjusted. AC currents with different phases are applied to the first and second coils 1a, 1b so that the coils 1a, 1b are deviated from each other, and the centers of the first and second coils 1a, 1b in the axial direction are connected. By matching the pitch between the magnetic poles of No. 4, the movable element can be reciprocated without using a mechanical spring.

The linear vibration motor described in Patent Document 4 includes a rectangular parallelepiped-shaped housing 10 having an accommodation space, a first magnet 11 and a second magnet 13 each accommodated in the accommodation space and fixed to the housing 10, and the housing 10. It has a clamp weight 120, a third magnet 121, a driving magnet 122, and a fourth magnet 123, and the magnetic pole of the third magnet 121 faces the adjacent magnetic pole of the first magnet 11. The magnetic pole of the fourth magnet 123 faces the adjacent magnetic pole of the second magnet 13, and the vibrator unit (mover) 12 is connected to the first magnet 11, the vibrator unit 12, and the second magnet 13. are arranged one by one along the vibration direction of the vibrator unit 12, and further include a guide groove component having a magnetic guide groove, and a magnetic guide floating at least partially surrounded by the magnetic guide groove. engagement structures 15 and 16 that include a guide rail component having a rail and that floats the vibrator unit 12 within the housing 10 and moves it along the vibration direction; A drive coil 14 that is open and surrounds its drive magnet 122 allows the vibrator unit to float without the use of mechanical springs.

WO2015/141648A1 US2016/172953A1 WO2010/119788A1 US2016/226359A1

However, in both of the vibration motors described in Patent Document 1 and Patent Document 2, the movable element is positioned by a mechanical spring, so problems such as deformation of the mechanical spring are likely to occur during assembly. There was a problem in that the level of difficulty was extremely high, and there was also the problem that the product had low impact resistance after completion, which could cause changes in characteristics or failure.

On the other hand, the vibration motors described in Patent Document 3 and Patent Document 4 do not use a mechanical spring for positioning the movable element, but instead have an electromagnetic circuit extending in the moving direction of the movable element. Therefore, there was a problem that it was difficult to downsize the housing.

Therefore, the present invention advantageously solves the above problems in a vibration motor that linearly vibrates a movable element by magnetically driving it and outputs the vibration, and has easy handling and assembly of parts, high shock resistance, Moreover, it is an object of the present invention to provide a linear vibration motor that is easy to strengthen the magnetic circuit, saves power, and is easy to downsize.

The present invention provides a stator having at least two coils wound annularly and arranged in parallel, a pair of stator magnets sandwiching the coils from both sides, and magnetic yokes that fixedly hold the coils and the stator magnets. and,
A weight movably held on a support shaft having both ends fixed and movable along the axis of the weight, and a movable element each having a movable element magnet fixedly held on the weight,
A linear vibration motor that drives the movable element by applying a voltage to the coil and energizing it to strengthen the magnetic flux passing through the coil,
The movable magnet and the stator magnet are arranged to face each other with a gap between them, and the magnetic attraction force between the movable magnet and the stator magnet causes the weight to move together with the movable magnet. It is characterized by comprising a magnetic spring that elastically supports the support shaft at a certain position.

In the linear vibration motor of the present invention, the stator includes at least two coils wound annularly and arranged in parallel, a pair of stator magnets sandwiching the coils from both sides, and the coils and the stator magnets. The movable element is composed of a weight that is movably held along the axis of the support shaft with both ends fixed, and a movable weight that is fixed and held on the weight. By applying a voltage to the coil and energizing it to strengthen the magnetic flux passing through the coil, the weight of the mover can be moved along with the mover magnet in the axial direction of the support shaft in one direction or in a reciprocating direction. Further, a mover magnet and a stator magnet are arranged facing each other with a gap between them, and a magnetic spring is formed by the magnetic attraction force between the mover magnet and the stator magnet. Accordingly, when the driving force is removed, the weight of the mover is pulled back to a fixed position (intended position) on the support shaft by the biasing force of the magnetic spring and positioned together with the mover magnet.

Therefore, according to the linear vibration motor of the present invention, since no mechanical spring is used, the parts can be easily handled and assembled, and the impact resistance can be improved. In addition, a coil for driving the mover is placed between the mover magnet and the magnetic yoke, and the stator magnet is placed in the magnetic yoke to strengthen the magnetic circuit, improve energy efficiency, and save power. Moreover, since the biasing force of the magnetic spring acts in the moving direction of the mover, there is no need to extend the electromagnetic circuit in the moving direction of the mover, and it is necessary to separately provide the magnetic circuit that drives the mover and the magnetic spring. Therefore, the stator can be easily downsized.

In addition, in the linear vibration motor of the present invention, the movable magnet is combined with one having a magnetic pole that attracts the stator magnet and one having a magnetic pole that repulses the stator magnet. It is preferable to configure this, and by doing so, the spring constant of the magnetic spring can be easily adjusted to a substantially constant value, and the driving of the weight by the resonance frequency can be stabilized.

Furthermore, in the linear vibration motor of the present invention, the movable magnet has magnetic poles that attract the stator magnet and magnetic poles that repel the stator magnet. , it is preferable to provide a non-magnetic pole section that does not have a magnetic pole.In this way, it is easy to adjust the timing of increase and decrease of the repulsion force when the weight moves, and the magnitude of the force, and the spring of the magnetic spring It becomes easy to keep the constant substantially constant with high precision, and furthermore, the driving of the weight by the resonance frequency can be stabilized.

Further, in the linear vibration motor of the present invention, it is preferable that the stator magnet and the mover magnet are respectively arranged along the axial direction of the support shaft and face each other in the radial direction of the support shaft. If this is done, the movable magnet and the stator magnet will attract each other, and rotation of the weight with respect to the support shaft can be suppressed.

Furthermore, in the linear vibration motor of the present invention, two sets of stator magnets and two sets of movable magnets are arranged symmetrically across the axis of the support shaft, and of these, the movable magnets are oriented in such a way that they attract each other. It is preferable to arrange it on a weight; in this way, the attraction forces between the mover magnet and the stator magnet become symmetrical with respect to the support shaft and cancel each other out, thereby reducing the frictional force of the bearing that supports the support shaft. In addition, the rotation of the mover relative to the support shaft can be suppressed with high precision, and since the mover magnets sandwich the weight and attract each other, it is possible to fix the mover magnet to the weight. This makes it possible to prevent the mover magnet from easily falling off from the weight even if it receives an impact or the like.

Furthermore, in the linear vibration motor of the present invention, it is preferable to arrange a magnetic fluid between the mover magnet and the stator magnet, or between the mover magnet and the coil. To reliably suppress the rotation of the weight relative to the support shaft when the weight moves, improve the shock resistance of the vibration motor, and stabilize the magnetic flux of the magnetic spring to obtain good resonance response. I can do it.

Further, in the linear vibration motor of the present invention, the stator includes a bottom plate having a rectangular shape and side walls connected in a cantilevered manner to both ends of the bottom plate in the width direction, and the coil and stator magnet are connected to the magnetic yoke. It is also preferable to have a case for storing the parts inside.This makes it easier to handle and assemble the parts.

Further, in the linear vibration motor of the present invention, the stator is connected in a cantilevered manner to the top plate facing the bottom plate of the case and both ends of the top plate in the longitudinal direction, and is positioned at the edge of the side wall of the case. It is preferable to have a side wall that cooperates with the case to define a sealed space inside the case, and a cover that stores the weight and mover magnet together with the support shaft inside the side wall. Easy to handle and assemble.

Furthermore, in the vibration motor of the present invention, it is preferable to arrange a buffer member on the cover or the weight to reduce the impact when the weight is driven.In this way, the noise when the weight is driven can be reduced. In addition, it is possible to improve the shock resistance of the vibration motor, and it is also possible to make the maximum amount of vibration substantially constant and improve the yield rate.

1 is a perspective view of the appearance of an embodiment of a linear vibration motor according to the present invention, viewed from above. FIG. 2 is a perspective view showing the linear vibration motor shown in FIG. 1 with the movable element and the stator separated. FIG. 3 is a perspective view of the linear vibration motor shown in FIG. 2 showing a state in which the mover is reversed. FIG. 3 is an exploded perspective view showing the configuration of a stator seen from above in the linear vibration motor shown in FIG. 2. FIG. FIG. 3 is an exploded perspective view showing the configuration of a stator in the linear vibration motor shown in FIG. 2 when viewed from below. FIG. 3 is an exploded perspective view showing the configuration of a mover seen from above in the linear vibration motor shown in FIG. 2. FIG. FIG. 3 is an exploded perspective view showing the configuration of a mover seen from below in the linear vibration motor shown in FIG. 2. FIG. (a) is a perspective view showing how the stator and mover are assembled in the linear vibration motor of the above embodiment, and (b) is a perspective view showing the stator and mover separated from each other. FIG. 4 is a diagram showing the direction of magnetic flux when no current is applied and the arrangement of magnetic poles when the movable element is driven. 9 is a diagram showing a cross section taken along line AA in FIG. 9. FIG. It is a graph showing the relationship between the moving distance of the movable element and the biasing force. It is a graph showing the relationship between the moving distance of the movable element and the biasing force. In another embodiment of the linear vibration motor according to the present invention, it is a diagram showing an example in which each magnetic pole group of the mover magnet is integrally molded by multi-pole magnetization. In the linear vibration motor of the previous embodiment, it is a diagram showing an example in which a magnetic fluid is provided between the mover magnet and the stator magnet and between the mover magnet and the coil.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Below, embodiments of a linear vibration motor of the present invention will be described in detail based on the drawings.
FIG. 1 is a perspective view of the external appearance of an embodiment of the linear vibration motor according to the present invention viewed from above, and FIG. 2 is a state in which the movable element and the stator are separated in the linear vibration motor shown in FIG. 1. 3 is a perspective view showing the state in which the mover is reversed in the linear vibration motor shown in FIG. 2. FIG. 4 is a perspective view showing the structure of the stator in the linear vibration motor shown in FIG. 2. 5 is an exploded perspective view showing the structure of the stator in the linear vibration motor shown in FIG. 2 as seen from the bottom, and FIG. 7 is an exploded perspective view showing the structure of the mover seen from above in the linear vibration motor shown in FIG. 2. FIG. 7 is an exploded perspective view showing the structure of the mover seen from below in the linear vibration motor shown in FIG. It is an exploded perspective view shown in state. In addition, FIG. 8(a) is a perspective view showing how the stator and mover are assembled in the linear vibration motor of the above embodiment, and FIG. 8(b) is a perspective view showing the stator and mover separated from each other. FIG.

Reference numeral 1 in FIGS. 1 to 8 indicates a stator. The stator 1 includes two coils 1a that are wound in a substantially rectangular parallelepiped shape and can be energized in series or in parallel, a pair of stator magnets 1b that sandwich the coils 1a from both sides, and the coils 1a and the stator magnets 1b. It has a magnetic material yoke 1c that holds fixedly. Further, reference numeral 2 denotes a case made of non-magnetic stainless steel or the like, in which the stator 1 is housed.

The case 2 has a U-shaped cross section, and is composed of a rectangular bottom plate 2a and a pair of side walls 2b that are bent and connected to both ends of the bottom plate 2a in the width direction.

Two sets of stators 1 are arranged on the side wall 2b of the case 2 so as to face each other across the axis of a support shaft (described later), and as shown in FIG. 8(b), one of the two sets is One set is arranged so that the magnetic pole on the front side of the stator magnet 1b is the north pole, and the other set is arranged so that the magnetic pole on the front side of the stator magnet 1b is the south pole.

The coil 1a may be made of magnet wire or the like and wound into a substantially rectangular parallelepiped shape, and is fixed to the magnetic yoke 1c with an adhesive or the like. Further, the stator magnet 1b may be made of a neodymium magnet or the like, and is fixed to the magnetic yoke 1c with an adhesive or the like. The magnetic yoke 1c is made of a substantially rectangular plate made of a magnetic material such as an electromagnetic steel plate, and is fixed to the side wall 2b of the case 2 by welding or the like.

The coil 1a is shown as an example in which a total of four coils 1a are provided, with two coils 1a arranged side by side as a set, but the two coils are configured so that they can be energized in series or in parallel. The two coil groups can also be configured to be energized in series or in parallel, and the two end wires of each coil 1a can be soldered or welded to the coil connection part of the board (described later). electrically connected.

The direction of the current flowing through the coil 1a can be a combination of the directions of the arrows shown in FIG. 8(b), or a combination in which all the directions of the arrows are reversed. can be reversed periodically.

Further, the reference numeral 3 in the figure is a movable element. The mover 3 includes a weight 3b held movably along the axis e of a support shaft 3a having both ends fixed, and a mover magnet 3c fixedly held on the weight 3b. . Further, reference numeral 4 denotes a cover made of non-magnetic stainless steel or the like and housing the movable element 3 therein.

The cover 4 is connected in a bent state to a top plate 4a facing the bottom plate 2a of the case 2 and both ends of the top plate 4a in the longitudinal direction, and cooperates with the case 2 by being positioned on the edge of the side wall 2b of the case 2. A side wall 4b which functions to define a sealed space inside the side wall 4b and has a U-shaped cross section can be used. The case 2 and the cover 4 can be provided with cutouts that can fit into each other, and the two are integrated by fitting the cutouts into each other and performing welding or the like on the fitting parts. It is now possible to do so.

The support shaft 3a may be made of high-strength stainless steel or the like, and both ends thereof are press-fitted into an opening 4c provided in the side wall 4b of the cover 4 and fixed by welding or the like. Further, the weight 3b may be made of a high specific gravity material such as a tungsten alloy and formed into a substantially rectangular parallelepiped, and a through hole 3d passing through the weight 3b in the longitudinal direction is formed in the center in the width direction. Furthermore, a recess 3e is formed at the end in the width direction symmetrically with the through hole 3d in between.

Bearings 3f formed in a substantially cylindrical shape from a copper-based or iron-copper-based oil-impregnated material are fixed to both ends of the through-hole 3d by press-fitting or the like, and the support shaft 3a is inserted through the bearings 3f. This allows the weight 3b to be held movably along the axis e of the support shaft 3a. Furthermore, a mover magnet 3c is arranged in the recess 3e of the weight 3b.

The mover magnet 3c is made of a neodymium magnet, an electromagnetic steel plate, or the like, and has rectangular parallelepiped magnetic poles magnetized in the radial direction of the support shaft 3a. The magnetic pole is preferably a single magnet or a group of magnetic poles formed by assembly, such as a single-pole magnetization, multi-pole magnetization, a multi-pole magnetized magnet including a non-magnetized section, and an electromagnetic steel plate. It is fixed to the recess 3e of the weight 3b by adhesive or the like.

As shown in FIG. 8, the mover magnet 3c has a magnetic pole opposite to the north pole of the stator magnet 1b as an south pole, and a non-magnetic pole section P and a north pole in order from there along the axial direction of the support shaft 3a. , an S pole, a N pole, and a non-magnetic pole section P, and the magnetic pole opposite to the S pole of the fixed magnet 1b is the N pole, and from there, a non-magnetic pole is formed along the axial direction of the support shaft 3a. Although a magnetic pole group consisting of a magnetic pole section P, an S pole, an N pole, an S pole, and a non-magnetic pole section P can be used, the present invention is not limited to what is shown in the drawings. Note that a non-magnetized section in a multi-pole magnetized magnet can be used as a non-magnetized section P.

By configuring the mover magnet 3c as described above, the two sets of mover magnets 3c are arranged to attract each other via the weight 3b, and the advantage is that the fixation of the mover magnet 3c on the weight 3b is strengthened. be. Further, the attractive force between the mover magnet 3c and the stator magnet 1b is strengthened by the magnetic flux passing through the coil 1a via the magnetic yoke 1c.

Further, reference numeral 5 in the figure is a buffer member made of a sponge-like synthetic resin or the like and adhesively fixed to the back surface of the side wall 4b of the cover 4. This buffer member 5 is for mitigating the impact when the weight 3b collides with the side wall 4b during driving, and may be provided on the longitudinal end face of the weight 3b instead or in addition.

Further, the reference numeral 6 in the figure is a board (such as a flexible printed wiring board (FPC)) made of an insulating resin layer and copper foil. The board 6 is pulled out to the outside of the motor through a notch provided in the case 1d, and is electrically insulated from the insulating resin layer except for the power terminal part and the coil connection part. It has a structure in which copper foil is sandwiched between resin layers (not shown), and is fixed to the case 2 with double-sided tape or the like.

To assemble the linear vibration motor having the above configuration, for example, first, the bearings 3f are fixed to both ends of the through hole 3d of the weight 3b by press-fitting, etc., and the mover magnet 3c is glued to the recess 3e of the weight 3b. do.

Further, the coil 1a is bonded to the magnetic yoke 1c, the magnetic yoke 1c is fixed to the side wall 2b of the case 2 by welding, etc., the board 6 is bonded to the bottom plate 2b of the case 2, and the end wire of the coil 1a is are connected to the terminals of the board 6, the stator magnet 1b is bonded to the magnetic yoke 1c, and the magnetic fluid 7 is applied to the magnetic pole face of the stator magnet 1b, the magnetic pole face of the mover magnet 3f, and the coil 1a as necessary. Apply to at least one of the front surfaces.

Then, the support shaft 3a is inserted through the through hole 3d of the weight 3b and the bearing 3f, and both ends of the support shaft 3a are fixed to the hole 4c provided in the side wall 4b of the cover 4 by press fitting, welding, etc., and the buffer member 5 is adhered to the side wall 4b of the cover 4, the cover 4 and the case 2 are fitted at the notch, and then the two are fixed and integrated by welding or the like.

FIG. 9 is a diagram showing the direction of the magnetic flux when the current is not energized and the arrangement of the magnetic poles when the mover is driven. FIG. 10 is a diagram showing the direction of the magnetic flux (the diameter of the support shaft FIG.

When the coil 1a is not energized, the mover 3 is kept at the most stable constant position in both the axial and circumferential directions of the support shaft 3a due to the magnetic attraction and repulsion between the mover magnet 3c and the stator magnet 1b. In this state, even if the mover 3 attempts to move in the axial direction of the support shaft 3a or rotate around the support shaft 3a due to external force, the mover 3 will not be supported by the magnetic spring. The force (pullback force) causes the movable element 3 to return to a stable fixed position, and movement of the movable element 3 along the support shaft 3a and rotation around the support shaft 3a are suppressed.

On the other hand, when the movable element 3 is driven as described below by energizing the coil 1a and moves in the axial direction of the support shaft 3a, the urging force by the magnetic spring changes as follows. That is, the two stator magnets 1b on both sides of the coil in FIG. The repulsive force of magnetic poles adjacent to each other via the non-magnetic pole section P is expressed as a repulsive force A, the attractive force of the magnetic pole of the mover magnet 3c facing B of the stator magnet 1b is expressed as an attractive force B, and the magnetic pole of this attractive force B has no effect on the magnetic pole. Assuming that the repulsive force between the adjacent magnetic poles via the magnetic pole section P is the repulsive force B, the movable force in the magnetic pole group constituting one magnetic spring is shown in FIG. When the repulsive magnetic pole of the mover magnet 3c, which is also used to drive the child 3, approaches the stator magnet 1b, the biasing force due to the repulsive force changes to a substantially increasing tendency, and conversely, the biasing force of the stator magnet 1b As the magnetic pole repelling moves away, the biasing force due to the repulsive force changes to a substantially decreasing tendency.

FIG. 12 shows the relationship between the moving distance of the movable element 3 and the biasing force; total A (attractive force A + repulsive force A), total B (attractive force B + repulsive force B), and total (A + B) of a set of movable element magnets 3c. ), which is a graph displayed as the total of the entire motor (A+B)×2.

By combining the two magnetic pole groups (stator magnet 1b) facing one set of mover magnets 3c, the spring constant of the magnetic spring becomes approximately constant, and the spring constant of the entire motor is determined by the combination of the four magnetic pole groups. be able to.

The magnitude of the attractive force and repulsive force at each position of the mover 3 depends on the magnetic strength and arrangement of the mover magnet 3c and the stator magnet 1b, the length in the axial direction of the support shaft 3a, and the diameter of the support shaft 3a. It is possible to adjust the thickness in the direction, the length of the non-magnetic pole section P, etc., and by appropriately changing the combination thereof, it is possible to configure a magnetic spring with an optimal spring constant.

In the linear vibration motor according to the present invention, when a voltage is applied between the power terminals of the substrate 6 to energize the coil 1a, the mover 3 receives a thrust in the axial direction of the support shaft 3a according to Fleming's left hand rule. As a result, the coil is driven to a position where it balances the urging force of the magnetic spring due to the attractive force and repulsive force of the stator magnet 1b and mover magnet 3c, and the voltage applied to the coil 1a is alternately reversed in polarity, for example. By using a sine wave or a rectangular wave, the movable element 3 reciprocates in the axial direction of the support shaft 3a. In particular, by making the frequency of the applied voltage waveform substantially coincide with the natural frequency of the spring constant of the magnetic spring and the mass of the movable element 3, it is possible to perform reciprocating motion with maximum amplitude due to resonance.

For example, even if the polarity of the voltage applied to the coil 1a is not changed, the voltage may be applied intermittently to drive the movable element 3 in one direction in the axial direction of the support shaft 3a, thereby causing the coil 1a to move in the opposite direction. The movable element 3 can also be reciprocated by repeating the operation of returning the movable element 3 to a stable position using the magnetic spring function caused by energization.

FIG. 13 is a diagram showing an example in which each magnetic pole group of the mover magnet 3c is integrally formed by multi-pole magnetization in another embodiment of the linear vibration motor according to the present invention. According to the linear vibration motor of this embodiment, even if the mover magnet 3c integrally formed by multi-pole magnetization is used, the same operation and effect as the mover magnet 3c configured by combining each magnetic pole can be achieved. Not only that, but in this case, it is possible to reduce the number of parts, and it is possible to realize efficient assembly of the linear vibration motor.

FIG. 14 is a diagram showing an example in which a magnetic fluid 7 is provided between the mover magnet 3c and the stator magnet 1b and between the mover magnet 3c and the coil 1a. As the magnetic fluid, for example, magnetic fine particles such as magnetite, which can be applied and adhered to the magnetic pole surface of the mover magnet 3c, the magnetic pole surface of the stator magnet 1b, and the front surface of the coil 1a, are mixed with hydrocarbon oil, fluorine oil, etc. It is preferable to use a known method in which a surfactant is dispersed in a solvent. According to this, when the weight 3b moves, rotation of the weight 3b with respect to the support shaft 3a can be reliably suppressed. In addition, it is possible to improve the shock resistance of the vibration motor, stabilize the magnetic flux constituting the magnetic spring, and obtain good resonance response.

According to the linear vibration motor of the above embodiment, since a mechanical spring is not used, the parts can be easily handled and assembled, and the impact resistance can be increased, and the magnetic spring strengthens the magnetic circuit. It is possible to improve energy efficiency and save power, and since the retracting action of the magnetic spring acts in the direction of movement of the mover M, there is no need for an electromagnetic circuit to extend in the direction of movement of the mover. Since there is no need to separately provide the magnetic spring and the magnetic spring, the stator can be easily downsized.

The embodiments of the linear vibration motor according to the present invention have been described above based on the drawings, but the linear vibration motor according to the present invention is not limited to the above embodiments, and can be modified as appropriate within the scope of the claims. For example, in a magnetic pole group constituting one magnetic spring, the stator magnet 1b may be two or more, and may be a multi-pole magnetized magnet having a plurality of magnetic poles or a non-magnetized section of non-magnetic poles. A magnet may also be applied.

Furthermore, the movable magnet 3c may have two or more attracting magnetic poles and two or more repelling magnetic poles instead of one attracting magnetic pole and one repelling magnetic pole. It is sufficient that the magnetic spring is configured by combining the attractive force and repulsive force of .

Regarding the coils 1a, in the embodiment of the present invention, the case where four coils are arranged as a whole is shown as an example, but the number of coils 1a may be three or less or five or more. The number of magnetic poles of the movable element magnet 3c that contribute to driving the movable element 3 may be changed according to the number of elements.

The non-magnetic pole section P may be omitted as long as the spring constant of the magnetic spring is substantially constant, and the non-magnetic pole section P can also be replaced with a non-magnetic magnetic material such as a steel plate or a non-magnetic material.

The shape of the substrate 6 is not limited to the illustrated shape, and if it is difficult to fix it to the case 2, it may be fixed to the magnetic yoke 1c. Further, the coil 1a may not be directly fixed to the magnetic yoke 1c, but may be fixed to the substrate 6 with the substrate 6 interposed therebetween.

Thus, according to the linear vibration motor of the present invention, the parts can be easily handled and assembled because no mechanical spring is used, and the shock resistance can be increased, and the magnetic spring strengthens the magnetic circuit. It is possible to improve energy efficiency and save power, and since the retracting action of the magnetic spring acts in the direction of movement of the mover, there is no need to extend the electromagnetic circuit in the direction of movement of the mover, and the magnetic circuit that drives the mover Since there is no need to separately provide the magnetic spring and the magnetic spring, the stator can be easily downsized.

1 Stator 1a Coil 1b Stator magnet 1c Magnetic yoke 2 Case 2a Bottom plate 2b Side wall 3 Mover 3a Support shaft 3b Weight 3c Mover magnet 3d Through hole 3e Recess 3f Bearing 4 Cover 4a Top plate 4b Side wall 4c Opening 5 Buffer member 6 Substrate 7 Magnetic fluid e Axis center P of support shaft Non-magnetic pole section

Claims (10)

a stator each having at least two coils wound in an annular shape and arranged in parallel, a pair of stator magnets sandwiching the coils from both sides, and magnetic yokes that fixedly hold the coils and the stator magnets;
A weight movably held on a support shaft having both ends fixed and movable along the axis of the weight, and a movable element each having a movable element magnet fixedly held on the weight,
A linear vibration motor that drives the movable element by applying a voltage to the coil and energizing it to strengthen the magnetic flux passing through the coil,
The movable magnet and the stator magnet are arranged to face each other with a gap between them, and the magnetic attraction force between the movable magnet and the stator magnet causes the weight to move together with the movable magnet. A linear vibration motor comprising a magnetic spring that elastically supports the support shaft at a certain position. The movable magnet is characterized in that it is composed of a combination of a magnet having a magnetic pole that attracts the stator magnet and a magnet that has a magnetic pole that repulses the stator magnet. The linear vibration motor described in 1. The movable magnet has a non-magnetic pole having no magnetic pole between one having a magnetic pole that attracts the stator magnet and the other having a magnetic pole that repulses the stator magnet. 3. The linear vibration motor according to claim 2, wherein the linear vibration motor has a section. 4. The linear vibration motor according to claim 1, wherein the stator magnet and the mover magnet are each arranged along the axial direction of the support shaft. The mover magnets include a set of magnets having magnetic poles that attract the stator magnet and magnets that have magnetic poles that repel the stator magnet, and the set is connected to the support shaft. The linear vibration motor according to any one of claims 1 to 4, characterized in that the linear vibration motor has two sets symmetrically in the axial direction of the motor. The stator magnets and the movable magnets are arranged in two sets each symmetrically in the radial direction with the axis of the support shaft in between, and the sets of the movable magnets are oriented toward the weights so as to attract each other. The linear vibration motor according to any one of claims 1 to 5, characterized in that the linear vibration motor is arranged in a. Any one of claims 1 to 6, characterized in that a magnetic fluid is disposed between the mover magnet and the stator magnet and at least one between the mover magnet and the coil. The linear vibration motor described in section. The stator includes a rectangular bottom plate and side walls connected to both widthwise ends of the bottom plate in an upright state, and has a case in which the coil and the stator magnet are housed together with the magnetic yoke. The linear vibration motor according to any one of claims 1 to 7, characterized in that: The stator is connected to a top plate facing the bottom plate of the case and both longitudinal ends of the top plate in a suspended state, and is positioned at an edge of the side wall, so that the stator cooperates with the case and extends inside the case. 9. The linear vibration motor according to claim 8, further comprising a cover that includes a side wall defining a sealed space and housing the weight and the movable magnet therein together with the support shaft . 10. The linear vibration motor according to claim 9, wherein at least one of the cover and the movable element has a buffer member that cushions a shock when the weight is driven.

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