WO2011013570A1

WO2011013570A1 - Vibration motor

Info

Publication number: WO2011013570A1
Application number: PCT/JP2010/062356
Authority: WO
Inventors: 雅彦宮崎; 徹史林; 貴弘高木; 英明宮本; 運也本間
Original assignee: 三洋電機株式会社; 三洋精密株式会社
Priority date: 2009-07-27
Filing date: 2010-07-22
Publication date: 2011-02-03
Also published as: JP2011030370A

Abstract

Disclosed is a vibration motor wherein a movable part can be easily made to vibrate even with a yoke disposed on a fixed part. The vibration motor (1) is provided with: a movable part (3) containing a permanent magnet (31); planar coils (25 and 26) that are disposed opposite the movable part (3) and that, when power is supplied thereto, generate a magnetic force that moves the movable part (3); and a fixed part (2) including an upper yoke (top case part (22)) and a lower yoke (yoke (28) and base plate (21)) that are disposed opposite the movable part (3), respectively above and below said movable part (3), so as to sandwich the movable part (3) and the planar coils (25, 26).

Description

Vibration motor

The present invention relates to a vibration motor including a movable part including a permanent magnet and a fixed part including a coil.

Conventionally, a vibration motor including a movable part including a permanent magnet and a fixed part including a coil is known (for example, see Patent Document 1).

Patent Document 1 discloses a vibration motor including a movable part including a permanent magnet, a box-shaped case, and a fixed part including a coil that generates a magnetic force to move the movable part when energized. . In Patent Document 1, the movable part is provided with a yoke disposed so as to surround the upper surface, the lower surface and the side surface of the permanent magnet. By surrounding the permanent magnet with the yoke, the magnetism of the permanent magnet is confined in the yoke and the magnetic leakage is suppressed, so that the magnetic force of the permanent magnet can be effectively used for driving the movable part.

Here, in order to suppress magnetic leakage, it is conceivable that the yoke is not provided in the movable part but is provided in the fixed part. For example, in the vibration motor disclosed in Patent Document 1, even when the yoke on the upper surface side of the permanent magnet of the movable portion is disposed on the upper surface of the fixed portion (case), the permanent magnet is formed by the yoke of the movable portion and the yoke of the fixed portion. It is possible to confine magnetism and suppress magnetic leakage.

Japanese Patent Laid-Open No. 2002-200460

However, when the yoke on the upper surface side of the permanent magnet of the movable part is disposed on the upper surface of the fixed part (case), the permanent magnet of the movable part and the yoke of the fixed part attract each other. The force to move to the side (upper side) acts on the movable part. In this case, since the force that the movable part tries to move upward acts as a resistance force to the vibration operation of the movable part, there is a problem that it becomes difficult to vibrate the movable part.

The present invention has been made to solve the above-described problems, and one object of the present invention is to make it possible to easily vibrate the movable portion even when the yoke is disposed on the fixed portion. It is to provide a vibration motor.

In order to achieve the above object, a vibration motor according to one aspect of the present invention includes a movable part including a permanent magnet and a magnetic force that is arranged to face the movable part and moves the movable part when energized. And a fixed portion including a movable portion and an upper surface side yoke and a lower surface side yoke arranged to face the movable portion on both the upper surface side and the lower surface side of the movable portion so as to sandwich the coil. And.

In the vibration motor according to one aspect of the present invention, the movable portion can be vibrated easily even when the yoke is disposed on the fixed portion due to the above configuration.

It is a perspective view which shows the structure of the vibration motor by 1st Embodiment of this invention. It is a disassembled perspective view which shows the vibration motor by 1st Embodiment shown in FIG. It is a disassembled perspective view which shows the vibration motor by 1st Embodiment shown in FIG. FIG. 5 is a cross-sectional view taken along line 50-50 in FIG. FIG. 5 is a cross-sectional view taken along line 51-51 in FIG. It is a top view which shows the coil part of the vibration motor by 1st Embodiment of this invention shown in FIG. It is typical sectional drawing which shows the coil part of the vibration motor by 1st Embodiment of this invention shown in FIG. It is a disassembled perspective view which shows the movable part and spring member of a vibration motor by 1st Embodiment of this invention shown in FIG. It is a graph which shows the simulation result of the vibration characteristic of the vibration motor by the Example (1st Embodiment of this invention). It is a graph which shows the simulation result of the vibration characteristic of the vibration motor by a comparative example. It is a disassembled perspective view which shows the vibration motor by 2nd Embodiment of this invention. It is sectional drawing corresponding to FIG. 4 of the vibration motor by 2nd Embodiment of this invention. It is sectional drawing corresponding to FIG. 5 of the vibration motor by 2nd Embodiment of this invention. It is a top view which shows the mobile telephone by 3rd Embodiment of this invention. It is sectional drawing which shows the mobile telephone by 3rd Embodiment of this invention. It is a perspective view which shows the magnet cover of the vibration motor by the 1st modification of 2nd Embodiment of this invention. It is a perspective view which shows the spring member of the vibration motor by the 2nd modification of 2nd Embodiment of this invention. It is a perspective view which shows the spring member of the vibration motor by the 1st modification of 1st Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
First, the structure of the vibration motor 1 (linear drive vibration motor) according to the first embodiment of the present invention will be described with reference to FIGS.

The vibration motor 1 according to the first embodiment of the present invention is a device that is built in a portable device (not shown) or the like and applies vibration to the portable device. As shown in FIG. 1, the vibration motor 1 includes a fixed portion 2, a movable portion 3 that vibrates with respect to the fixed portion 2, and a spring member 4 that supports the movable portion 3 so as to vibrate.

As shown in FIGS. 2 and 3, the fixing portion 2 includes a metal box-like case 23 including a base plate (lower case portion) 21 and an upper case portion 22, and a yoke-integrated coil portion fixed to the base plate 21. 24. The base plate 21 and the upper case portion 22 are made of a magnetic metal material (for example, SPCC).

The base plate 21 and the upper case portion 22 are fixed by welding at six

welding portions

23a, 23b, 23c, 23d, 23e, and 23f (see FIG. 1). Specifically, as shown in FIGS. 1 to 3, protrusions 21a are formed at both ends in the X direction of the base plate 21, and the protrusions of the base plate 21 are formed at the lower ends of the side surfaces of the upper case part 22. A notch 22a into which 21a is fitted is formed. Two portions (welded

portions

23a and 23b) are welded at the fitting portion between the protruding portion 21a and the cutout portion 22a. Further, the upper end portion 21c of the side surface 21b of the base plate 21 and the end portion 22c in the Y direction of the upper surface 22b of the upper case portion 22 are respectively provided at two positions at both ends in the Y direction of the case 23 (welded

portions

23c, 23d, 23e). And 23f).

The case 23 (the base plate 21 and the upper case part 22) has a function as a magnetic shield (yoke) for suppressing the leakage of magnetism from the case 23 to the outside by being made of a magnetic material. As shown in FIGS. 2 to 4, an opening 21d is formed in the lower surface of the base plate 21, and the yoke-integrated coil portion 24 is disposed so as to be fitted into the opening 21d. The base plate 21 and the yoke integrated coil portion 24 are fixed by being bonded at two bonding portions. Specifically, in the region corresponding to the opening 21d, the lower surface of a portion 21e (see FIGS. 2 and 3) that protrudes inwardly from the side surface 21b of the base plate 21 and the upper surface of the yoke-integrated coil unit 24 are Y. Both ends in the direction are linearly bonded. The base plate 21 and the upper case portion 22 are examples of the “lower surface side yoke” and the “upper surface side yoke” of the present invention, respectively.

Further, as shown in FIG. 2, a pair of rails 21 g protruding upward is provided integrally with the base plate 21 on the upper surface 21 f of the base plate 21 (the lower inner surface of the case 23). A pair of rails 21g is provided in each of the regions on both sides in the X direction across the opening 21d. The pair of rails 21g is formed so as to extend in the X direction, which is the vibration direction of the movable portion 3, from the end portion of the base plate 21 in the X direction (end portion on the protruding portion 21a side) to the opening portion 21d. The pair of rails 21g are arranged at positions slightly corresponding to the inner side portions from both ends of the movable portion 3 in the Y direction. The surface of the rail 21g is rounded, and the shape of the surface of the rail 21g in the cross section in the direction (Y direction) orthogonal to the direction in which the rail 21g extends (X direction) is a substantially arc shape.

Further, the entire surface of the base plate 21 including the surface of the rail 21g is subjected to fluororesin processing. Specifically, Nimflon treatment (Nimflon is a registered trademark) is applied. The Nimflon treatment is a plating treatment having both characteristics of Teflon (polytetrafluoroethylene: PTFE) (Teflon is a registered trademark) having a low friction coefficient and electroless Ni. The Nimflon treatment is performed by mixing PTFE particles in an electroless plating solution and plating. Similarly, the entire surface of the upper case portion 22 is also treated with Nimflon.

As shown in FIGS. 6 and 7, the yoke-integrated coil portion 24 includes flat

planar coils

25 and 26 having a two-layer wiring structure, and mounting terminals 27a exposed on the lower surface side of the yoke-integrated coil portion 24. And a wiring layer 27 including the mounting terminals 27b and a yoke 28 made of a magnetic material (for example, SPCC, silicon steel plate, etc.). The planar coils 25, 26, the wiring layer 27 and the yoke 28 are formed as an integral part with an insulating resin 29. More specifically, as shown in FIG. 7, the planar coil 25 and the yoke 28 are integrated with a resin 29a, and the planar coil 26 and the wiring layer 27 formed on the upper and lower surfaces of the resin 29a are made of a resin 29b. Covered. A part of the wiring layer 27 including the mounting terminal 27a and the mounting terminal 27b is exposed through the opening 29c of the resin 29b on the lower surface side. Each of the

planar coils

25 and 26 has a rectangular outline in plan view, and spirals so as to spread from the inside toward the outside in the XY plane (surface formed by the X direction and the Y direction). It is formed in a shape. Each of the

planar coils

25 and 26 is an example of the “coil” in the present invention. The yoke 28 is an example of the “lower surface side yoke” in the present invention.

The planar coils 25 and 26 are electrically connected in series by one current line. Specifically, as shown in FIG. 6, the first-layer current line 25a constituting the planar coil 25 is wound spirally counterclockwise from the outside when viewed from above. Yes. As shown in FIGS. 6 and 7, the outer end of the first-layer current line 25a of the planar coil 25 is exposed on the surface of the lower surface of the yoke-integrated coil section 24 through a connecting line 25b extending in the thickness direction. Connected to the mounting terminal 27a.

As shown in FIG. 5, the second layer current line 26a constituting the planar coil 26 is wound in a spiral shape counterclockwise from the inside to the outside when viewed from above. As shown in FIGS. 6 and 7, the outer end of the second-layer current line 26a of the planar coil 26 is connected to the mounting terminal 27b via a connection line 26b extending in the thickness direction (Z direction). Yes. The inner end portion of the first layer current line 25a constituting the planar coil 25 and the inner end portion of the second layer current line 26a constituting the planar coil 26 are the same as the yoke when viewed in plan. The body coil portions 24 are connected to each other in the vicinity of the central portion 24a.

As shown in FIGS. 5 and 6, the

planar coils

25 and 26 are wound in a spiral shape with a predetermined space having a width W4 in the X direction at the center. The width W1 (see FIG. 5) in the X direction of the outermost periphery of the

planar coils

25 and 26 is substantially equal to the width W2 (see FIG. 8) in the X direction of the permanent magnet 31. The width W3 (see FIG. 5) in the X direction of the yoke-integrated coil portion 24 is larger than the width W2 in the X direction of the permanent magnet 31. Further, as shown in FIG. 4, the center lines O1 and O2 of the portions around which the current lines of the

planar coils

25 and 26 are wound are a center line O3 of the first magnet 311 and a center line O4 of the second magnet 312 described later. It is located outside.

As shown in FIG. 8, the movable part 3 includes a flat permanent magnet 31, a weight 32 made of a material having a large specific gravity (for example, tungsten), and a non-magnetic material (for example, phosphorous) that covers the permanent magnet 31 and the weight 32. Bronze) magnet cover 33. The movable part 3 does not include a yoke (magnetic material). The permanent magnet 31 is a permanent magnet made of a ferromagnetic material such as ferrite or neodymium. The permanent magnet 31 is formed in a substantially rectangular shape when seen in a plan view. The weight 32 is formed in a frame shape whose outer shape is substantially rectangular when viewed in a plan view, and has an opening 32 a having substantially the same shape as the permanent magnet 31. A permanent magnet 31 is fitted in the opening 32 a of the weight 32. The permanent magnet 31 and the weight 32 have substantially the same thickness. The magnet cover 33 is integrated with the permanent magnet 31 and the weight 32 so as to cover the entire upper surface of the permanent magnet 31 and the weight 32, the entire side surface in the X direction of the weight 32, and a part of the lower surface of the weight 32. It is fixed to. The lower surface of the magnet cover 33 is located below the lower surfaces of the permanent magnet 31 and the weight 32. Further, the entire surface of the magnet cover 33 is subjected to Nimflon treatment.

As shown in FIGS. 4 and 8, the permanent magnet 31 is composed of two permanent magnets including a first magnet 311 and a second magnet 312 in which a pair of magnetic poles are magnetized in the thickness direction (Z direction). . Specifically, the first magnet 311 is arranged on the arrow X1 direction side with the center line of the movable portion 3 as a boundary, and the second magnet 312 is arranged on the arrow X2 direction side. In the first magnet 311, the side facing the yoke-integrated coil unit 24 is an N pole surface 311 a magnetized to N pole, and the opposite side is an S pole surface 311 b magnetized to S pole. In the second magnet 312, the side facing the yoke-integrated coil portion 24 is an S pole surface 312 a magnetized to the S pole, and the opposite side is an N pole surface 312 b magnetized to the N pole.

The first magnet 311 and the second magnet 312 are adjacent to the N pole surface 311a and the S pole surface 312a on the surface on the yoke integrated coil portion 24 side, and opposite to the yoke integrated coil portion 24 side. The S pole face 311b and the N pole face 312b are disposed adjacent to each other. The first magnet 311 and the second magnet 312 are in close contact with each other due to the attractive force between the N pole surface 311a and the S pole surface 312a adjacent to each other and the attractive force between the S pole surface 311b and the N pole surface 312b. And are fixed to each other by an adhesive or the like.

As described above, as shown in FIGS. 4 and 5, the movable portion 3 is disposed to face the magnetic pole surface of the permanent magnet 31 so as to be parallel to the yoke-integrated coil portion 24. The movable portion 3 is linearly moved in the directions of arrows X1 and X2 parallel to the yoke-integrated coil portion 24 inside the case 23 while being supported by the spring member 4. Here, the term “parallel” includes not only a state parallel to each other but also a state deviated from a parallel state (a state inclined at a predetermined angle) to the extent that the movable portion 3 does not hinder linear movement. At this time, the side surface in the Y direction of the case 23 has a function as a guide when the movable portion 3 moves in the directions of the arrows X1 and X2.

As shown in FIGS. 5 and 8, the spring member 4 includes a dish part 41 and a pair of

spring parts

42 and 43 provided on both sides of the dish part 41. The plate part 41 and the

spring parts

42 and 43 are made of a plate-like nonmagnetic material (for example, SUS304). The lower surface of the dish part 41 and the upper surface of the magnet cover 33 are fixed by being bonded. A rectangular opening 41 a is formed at the center of the dish 41. The opening 41a and the permanent magnet 31 are configured to have substantially the same size when viewed in a plan view. The SUS 304 constituting the dish part 41 is basically non-magnetic, but may be magnetized during processing, and thus the magnetic field lines of the permanent magnet 31 may be shielded by the dish part. Here, by providing the opening 41 a, it is possible to suppress the lines of magnetic force from the permanent magnet 31 from being shielded by the spring member 4. Thereby, all or part of the attractive force (downward attractive force) between the yoke 28 and the base plate 21 of the yoke-integrated coil portion 24 and the permanent magnet 31 is reduced between the upper case portion 22 and the permanent magnet 31. It is offset by the suction force (upward suction force). The dish portion 41 is an example of the “attachment portion” in the present invention.

As shown in FIGS. 4 and 5, the spring portion 42 is provided so as to stretch the side surface of the magnet cover 33 and the side surface of the upper case portion 22 on the arrow X1 direction side of the movable portion 3. The spring member 4 supports the movable portion 3 so as not to contact the case 23 (the base plate 21 and the upper case portion 22). That is, the movable portion is caused by the difference between the attractive force between the permanent magnet 31 and the upper case portion 22 and the attractive force between the permanent magnet 31 and the yoke 28 and the base plate 21 of the yoke-integrated coil portion 24. Even when 3 is pulled upward or downward with a predetermined force, the spring member 4 has a force larger than the vertical suction force applied to the movable portion 3 (the vertical suction force applied to the movable portion 3). The movable part 3 is configured to be supported in the vertical direction by the strength to withstand.

More specifically, the spring part 42 includes a first part 42 a formed integrally with the dish part 41, and a second part 42 b welded to the first part 42 a and the upper case part 22. The first portion 42a and the second portion 42b are leaf springs. The first portion 42a is in contact with the side surface of the magnet cover 33 at the end in the arrow Y1 direction, and is curved so that the end in the arrow Y2 direction is separated from the side surface of the magnet cover 33. The second portion 42b is in planar contact with the side surface in the arrow X1 direction of the upper case portion 22 at the end portion in the arrow Y1 direction, and the end portion in the arrow Y2 direction is from the side surface in the arrow X1 direction of the upper case portion 22. It is curved to be separated. The end portion in the arrow Y2 direction of the first portion 42a and the end portion in the arrow Y2 direction of the second portion 42b are welded in a surface contact state. The spring portion 43 has a configuration similar to that of the spring portion 42, and includes a first portion 43a and a second portion 43b having the same structure as the first portion 42a and the second portion 42b. With the above configuration, the

spring portions

42 and 43 are configured to bias the movable portion 3 in opposite directions.

The vibration motor 1 is fixedly attached to the portable device by soldering the mounting

terminals

27a and 27b to terminals (not shown) formed on the mother board of the portable device, for example.

Next, the operation of the vibration motor 1 according to the first embodiment of the present invention will be described with reference to FIGS.

First, a drive current is supplied to the current lines constituting the

planar coils

25 and 26 via the mounting

terminals

27a and 27b. Thereby, a current in a direction (arrow Y1 and Y2 directions) perpendicular to the vertical magnetic field generated between the N pole surface 311a and the S pole surface 312a of the movable part 3 flows in the planar coil 25 and the planar coil 26. At this time, the direction of the current flowing in the portion on the arrow X1 direction side (hereinafter referred to as the right portion) when viewed in plan from the central portion of the planar coil 25 and the planar coil 26 (the central portion of the spiral), and the arrow from the central portion. The direction of the current flowing through the portion on the X2 direction side (hereinafter, the left portion) is opposite. The Lorentz force acts in the direction of the arrow X1 on the right side portions of the

planar coils

25 and 26 through which the current flows due to the magnetic field generated by the permanent magnet 31, and the reaction force acts on the N pole surface 311a of the first magnet 311 in the direction of the arrow X2 To work. At the same time, a Lorentz force acts in the direction of the arrow X1 on the left portions of the

planar coils

25 and 26, and the reaction force acts on the south pole face 312a of the second magnet 312 in the direction of the arrow X2. As described above, the movable portion 3 is linearly moved in the arrow X2 direction.

Then, after a predetermined time, by supplying a drive current in the opposite direction, the movable part 3 is linearly moved in the direction of the arrow X1 by the same action as described above. In this way, by switching the direction of the drive current at a predetermined frequency, the movable portion 3 is linearly moved alternately in the directions of the arrows X1 and X2 and reciprocated. At this time, the magnetic flux generated between the N-pole surface 311a of the first magnet 311 and the S-pole surface 312a of the second magnet 312 is absorbed by the yoke 28 and the base plate 21 and selectively inside the yoke 28 and the base plate 21. Since it passes through, almost no magnetic flux that extends to the outside of the case 23 is generated. Further, most of the magnetic flux generated between the S pole surface 311b of the first magnet 311 and the N pole surface 312b of the second magnet 312 is absorbed by the upper case portion 22 and selectively inside the upper case portion 22. Since it passes through, almost no magnetic flux that extends to the outside of the case 23 is generated.

At this time, the movable part 3 has a force in a direction toward the center along the directions of the arrows Y1 and Y2, respectively, due to the electromagnetic force generated from the current line extending in the X direction among the

planar coils

25 and 26, or A force in a direction of pulling outward from the center along the directions of the arrows Y1 and Y2 is applied.

In the vibration motor 1 according to the first embodiment of the present invention, the following effects can be obtained.

(1) By constructing the vibration motor 1 of lateral vibration (vibration in the directions of arrows X1 and X2), it is easy to reduce the thickness as compared with the vibration motor of vertical vibration (vibration in the vertical direction (Z direction)).

(2) The movable part 3 is provided that is movable along the direction (arrow X1 and X2 directions) along the surfaces of the

planar coils

25 and 26. Accordingly, it is necessary to provide a moving range (moving space in the vertical direction) of the movable part 3 as compared with the case where the movable part 3 is linearly moved in the vertical direction using a coil having a large thickness in the vertical direction (Z direction). Therefore, the degree of freedom of design for reducing the thickness in that direction can be ensured. As a result, the vibration motor 1 that can be thinned can be provided.

(3) The planar coils 25 and 26 were spirally formed so as to be flat along the moving direction of the movable part 3. This eliminates the need to provide a region in the height direction (height direction) due to the coil winding surface, compared to the case where the coil winding surface is arranged in a direction perpendicular to the moving direction of the movable part. The thickness of the yoke-integrated coil portion 24 can be reduced. Therefore, the vibration motor 1 can be thinned.

(4) The movable part 3 including the permanent magnet 31 is not provided with a yoke, and the fixed part 2 including the

planar coils

25 and 26 is opposed to the movable part 3 on both the upper surface side and the lower surface side thereof. The upper surface side yoke (upper case portion 22 that functions as a yoke) and the lower surface side yoke (the yoke 28 and the base plate 21 that functions as a yoke) are provided. With this configuration, the attractive force (upward attractive force) between the permanent magnet 31 of the movable portion 3 and the upper case portion 22, the permanent magnet 31 of the movable portion 3, the yoke 28, and the base plate 21 It is possible to balance the suction force (downward suction force). As a result, it is possible to reduce the vertical force applied to the movable portion 3 due to the fact that the yoke is disposed on the fixed portion 2. Thereby, even when the yoke is arranged on the fixed portion 2, the movable portion 3 can be easily vibrated.

(5) Movable portion 3 is attracted to the upper surface side of movable portion 3 by upper surface side yoke (upper case portion 22 functioning as a yoke) and movable by lower surface side yoke (yoke 28 and base plate 21 functioning as a yoke) The part 3 cancels out at least a part of the force attracted to the lower surface side of the movable part 3. By comprising in this way, the force of the up-down direction added to the movable part 3 can be adjusted easily. Thereby, the Q value of the vibration system of the vibration motor 1 can be easily adjusted. Here, the Q value is a dimensionless number that characterizes the vibration state, and is an amount that represents the sustained characteristic of vibration of the resonating system. When the Q value is high, the vibration continues for a long time, and when it is low, the vibration decreases immediately.

(6) The planar coils 25 and 26 are provided only on the lower surface side of the movable part 3. In the first embodiment, as described in the above effect (4), the movable part 3 can be easily vibrated, so that the

planar coils

25 and 26 are not provided on the upper surface of the movable part 3 but provided only on the lower surface side. In this case, the movable part 3 can be sufficiently vibrated.

(7) The spring member 4 is provided with a dish part 41 fixed to the movable part 3 so as to cover the upper surface of the movable part 3, and the dish part 41 is provided with an opening 41a. Thereby, even if it is a case where the plate part 41 is a magnetic body, the magnetic force line of the permanent magnet 31 can be passed to the upper case part 22 side through the opening part 41a. Thereby, even when the upper surface of the movable part 3 is covered with the dish part 41, it is possible to suppress a reduction in the attractive force (upward attractive force) between the upper case part 22 and the permanent magnet 31. . As a result, it is possible to suppress the balance between the upward suction force and the downward suction force of the movable part 3 from being lost.

(8) A magnet cover 33 made of a non-magnetic material is provided on the movable part 3. Thereby, the permanent magnet 31 can be supported by the magnet cover 33 without shielding the magnetic lines of force of the permanent magnet 31.

(9) Due to the configuration of the vibration motor 1, the Q value in the vibration amount-frequency characteristics (relation between the vibration amount of the object (eg, mobile phone) to be vibrated by the vibration motor 1 and the frequency of the input voltage) is reduced (vibration amount The amount of vibration of the object to be vibrated by the vibration motor 1 can be increased. If the Q value is lowered, the amount of vibration does not increase unless an input voltage with an accurate frequency is input as in the case where the Q value is high (if the input voltage deviates slightly from the resonance frequency, the amount of vibration decreases rapidly. Unlike the case), a large amount of vibration can be obtained in a wider frequency band. As a result, a sufficient amount of vibration can be obtained even when the actual resonance frequency (f0) deviates from the design value due to manufacturing errors or assembly errors of components of the vibration motor 1. Further, since the Q value can be reduced, the time from the resonance state until the vibration stops can be reduced. Thereby, the stop characteristic of the vibration motor 1 can be improved.

(10) The movable part 3 was not provided with a yoke, and the fixed part 2 was provided with a yoke. With this configuration, not only the Lorentz force but also the attractive force between the permanent magnet 31 and the yoke (the yoke 28, the base plate 21 and the upper case portion 22) of the fixed portion 2 contributes to the vibration of the movable portion 3. be able to. Thereby, the vibration amount of the target object which the vibration motor 1 vibrates can be enlarged. In the vibration motor 1, it is possible to suppress a decrease in the vibration amount even when the Q value is reduced as described above.

(11) A space having a width W4 in the X direction is provided in the central portion of the

planar coils

25 and 26. Thereby, when the movable part 3 moves in the arrow X1 direction, the Lorentz force acting in the arrow X1 direction acting between the right side portions of the

planar coils

25 and 26 and the S pole surface 312a of the second magnet 312 is suppressed. Can do. Thereby, the reaction force of the Lorentz force acting on the permanent magnet 31 (second magnet 312) in the arrow X2 direction can be suppressed. Further, when the movable part 3 moves in the direction of the arrow X2, it is possible to suppress the Lorentz force acting in the direction of the arrow X2 acting between the left portions of the

planar coils

25 and 26 and the N pole surface 311a of the first magnet 311. it can. Thereby, the reaction force of the Lorentz force acting in the arrow X1 direction with respect to the permanent magnet 31 (first magnet 311) can be suppressed. Thus, since the force (reaction force of Lorentz force) acting in the direction opposite to the moving direction of the movable part 3 is suppressed, the driving amount of the movable part 3 can be increased.

Next, a simulation for verifying the effect (9) will be described.

In this simulation, as an example, a model (example) in which the Q value is reduced by using the structure of the first embodiment in which the movable body is not provided with a yoke and magnetic bodies (yokes) are arranged above and below the fixed portion. Assumed. As a comparative example, a model (comparative example) in which a yoke surrounding a permanent magnet is provided on a movable part as in Patent Document 1 described above. And the vibration characteristic was verified about the Example and the comparative example.

The simulation results of the example and the comparative example are shown in FIGS. 9 and 10, respectively. 9 and 10, the horizontal axis represents the frequency of the input voltage (resonance frequency is f0), and the vertical axis represents the acceleration and vibration amount of the object that the vibration motor vibrates. In the embodiment, the Q value is reduced (Q value = 10) by adjusting the suction force in the vertical direction of the movable part to apply the resistance force against the vibration of the movable part. On the other hand, in the comparative example, since the force in the vertical direction does not act on the movable part and the resistance force against the vibration of the movable part is small, the Q value is large (Q value = 40).

Considering the case of driving the vibration motor so that the acceleration exceeds the predetermined value g0 for the example and the comparative example.

9 and 10, the frequency width A1 in which the acceleration in the example exceeds g0 is larger than the frequency width A2 in which the acceleration in the comparative example exceeds g0. That is, in the embodiment, by allowing the Q value to be lower than that in the comparative example, the allowable range of deviation of the input voltage with respect to the resonance frequency f0 is larger than that in the comparative example. This means that even when manufacturing errors and assembly errors of vibration motor parts occur, the embodiment has less variation between products than the comparative example (the ratio of obtaining desired performance is higher). Show.

Further, the maximum width of the vibration amount deviation corresponding to the allowable width of the input frequency (frequency of the input voltage) is B1 in the example, but B2 larger than B1 in the comparative example. That is, in the example, the maximum error of the vibration amount between products is B1, and in the comparative example, the maximum error is B2. Therefore, in the comparative example in which the maximum error of the vibration amount is large, in order not to cause the movable part to collide with the case, the distance between the inner walls of the case (the distance between the side surfaces in the X direction of the upper case part 22 (see FIG. 1)). It needs to be designed to be larger. In the embodiment, since the maximum error of the vibration amount is small, the distance between the inner walls of the case can be designed to be small. As a result, it is considered that the size of the vibration motor can be reduced.

(Second Embodiment)
Next, the structure of the vibration motor 101 according to the second embodiment will be described with reference to FIGS. In the second embodiment, an example in which the movable portion 103 contacts (slids) the case 23 will be described, unlike the first embodiment in which the movable portion 3 does not contact (slide) the case 23.

As shown in FIGS. 11 to 13, the vibration motor 101 includes a fixed portion 2 (case 23 and yoke-integrated coil portion 24), a movable portion 103, and a spring member 104 made of a nonmagnetic material (for example, SUS304). It has. The movable portion 103 includes a permanent magnet 31, a weight 32, and a magnet cover 133 made of a nonmagnetic material (for example, phosphor bronze). The structure other than the magnet cover 133 and the spring member 104 is the same as that of the vibration motor 1 according to the first embodiment.

As shown in FIGS. 11 and 13, four protrusions 133 a that protrude upward are formed on the upper surface of the magnet cover 133. Two rectangular openings 141 a are formed in a region corresponding to the protruding portion 133 a of the plate portion 141 of the spring member 104. That is, as shown in FIG. 12, in a state where the magnet cover 133 and the plate portion 141 of the spring member 104 are bonded, the protruding portion 133 a of the magnet cover 133 is connected to the plate portion 141 through the opening 141 a of the plate portion 141. It protrudes above the upper surface. Thereby, even when the movable part 103 is pulled by the upper case part 22 and moves to the upper case part 22 side, the movable part 103 and the upper case part 22 are connected via the protrusions 133a (of the four protrusions 133a). It is configured to abut (at four points on the tip). The dish portion 141 is an example of the “attachment portion” in the present invention.

As shown in FIG. 12, the magnet cover 133 has a side surface portion 133b that covers the side surface of the weight 32 in the X direction. A sliding portion 133c is formed at the lower end of the side surface portion 133b. The sliding portion 133c protrudes downward from the lower surfaces of the permanent magnet 31 and the weight 32. The sliding part 133c is formed by being bent so that the lower end of the side part 133b is in the substantially horizontal direction.

11 and 13, the spring member 104 includes

spring portions

142 and 143 in addition to the plate portion 141. The spring portion 142 is in contact with the first portion 142a that contacts the side surface in the X direction of the magnet cover 133, the elastic deformation portion 142c having the folded portion 142b, and the side surface in the X direction of the upper case portion 22. It has the 2nd part 142d which touches, and the 3rd part 142e which contact | abuts the side surface of the Y direction of the upper case part 22 planarly. From the first portion 142a toward the elastic deformation portion 142c, the elastic deformation portion 142c is separated from the side surface 133b of the magnet cover 133 with a bent portion 142f positioned near the center in the Y direction as a starting point. Similarly, the elastic deformation portion 142c is separated from the side surface of the upper case portion 22 from the second portion 142d toward the elastic deformation portion 142c, starting from a bent portion 142g located in the vicinity of the center portion in the Y direction. The spring member 104 is bent along the shape of the side surface of the upper case portion 22 from the second portion 142d to the third portion 142e. The third portion 142e and the side surface in the Y direction of the upper case portion 22 are fixed by welding. Further, the spring part 143 has the same configuration as the spring part 142.

As shown in FIG. 12, the spring member 104 supports the movable portion 103 so that the movable portion 103 contacts the base plate 21. That is, the attractive force between the permanent magnet 31 and the upper case portion 22 is configured to be smaller than the attractive force between the permanent magnet 31 and the yoke 28 and the base plate 21 of the yoke-integrated coil portion 24. When the movable portion 103 is pulled downward with a predetermined force due to the difference in the suction force, the spring member 104 moves the movable portion 103 in the vertical direction (Z direction) with a force smaller than the predetermined force. It is configured to support. Thereby, the movable part 103 vibrates while sliding the sliding part 133c of the magnet cover 133 and the rail 21g of the base plate 21.

The vibration motor 101 according to the second embodiment of the present invention can obtain the following effects in addition to the effects (1) to (11).

(12) The surface (inner surface) of the case 23 on the side where the yoke 28 is disposed and the movable portion 103 are configured to abut via the rail 21g. With this configuration, even when the case 23 (base plate 21) and the movable portion 103 slide, the contact area is reduced unlike the case where the inner surface of the base plate 21 and the movable portion 103 are in planar contact. Therefore, the frictional force between the base plate 21 and the movable part 103 can be reduced. Thereby, it can suppress that the vibration amount of the movable part 103 falls.

(13) The surface (inner surface) of the upper case portion 22 of the case 23 and the movable portion 103 are configured to come into contact with each other via the protruding portion 133a of the magnet cover 133. By comprising in this way, even when the case 23 (upper case part 22) and the movable part 103 slide, unlike the case where the inner surface of the upper case part 22 and the movable part 103 contact in a planar shape, Since the contact area can be reduced, the frictional force between the upper case portion 22 and the movable portion 103 can be reduced. Thereby, it can suppress that the vibration amount of the movable part 103 falls.

(14) The surface (inner surface) of the case 23 and the movable portion 103 are configured to contact each other via a rail 21g formed so as to extend along the moving direction of the movable portion 103. With this configuration, the case 23 and the movable part 103 can always be brought into contact with each other via the rail 21g at any position in the movement range due to the vibration of the movable part 103.

(15) The surface of the case 23 and the magnet cover 133 are configured to contact each other via the rail 21g. By comprising in this way, it can prevent that the permanent magnet 31 and the case 23 slide. Thereby, since it is possible to prevent the permanent magnet 31 from being worn, the reliability of the vibration motor 1 can be improved.

(16) The rail 21g is formed so that the surface of the contact portion of the rail 21g with the movable portion 103 is rounded. With this configuration, the contact area between the rail 21g and the movable portion 103 can be further reduced, and the rail 21g and the movable portion 103 can be smoothly slid.

(17) The entire surface of the base plate 21 including the rail 21g, the entire surface of the upper case portion 22, and the entire surface of the magnet cover 133 including the protruding portion 133a are subjected to fluororesin processing. By comprising in this way, the friction coefficient between the rail 21g and the magnet cover 133 and the friction coefficient between the protrusion part 133a and the upper case part 22 can be reduced. Thereby, even when the case 23 and the movable part 103 slide, it can suppress that the kinetic energy of the movable part 103 falls by friction. Therefore, it is possible to suppress a decrease in the vibration amount of the movable portion 103.

(Third embodiment)
FIG. 14 and FIG. 15 are diagrams for explaining an example of a portable device using the vibration motor according to any one of the first and second embodiments of the present invention. FIG. 15 is a cross-sectional view of a portion including the vibration motor of FIG.

The vibration motor 1 (101) according to any of the first and second embodiments of the present invention can be used for a mobile phone 500 or the like as shown in FIGS. The mobile phone 500 includes a vibration motor 1 (101), a CPU 510 (see FIG. 15), and a display unit 520. The vibration motor 1 (101) is disposed on the surface of the mobile phone 500 opposite to the side where the display unit 520 is disposed. Display unit 520 is configured by a touch panel panel, and is configured to operate cellular phone 500 by pressing button unit 520 a displayed on display unit 520. The vibration motor 1 (101) vibrates when it is detected that the button unit 520a displayed on the display unit 520 is pressed or when the manner mode is set when a call is received. It is controlled by the CPU 510.

The following effects can be obtained with the mobile phone 500 including the vibration motor 1 (101) according to the third embodiment of the present invention.

(18) By providing the vibration motor 1 (101) as a vibration source, the thickness of the vibration motor 1 (101) can be reduced, so that the mobile phone 500 can be reduced in thickness.

(19) Since the magnetic flux leakage from the vibration motor 1 (101) is suppressed by providing the vibration motor 1 (101), even when a ferromagnetic material such as iron approaches the mobile phone 500, The influence on the operation of the vibration motor 1 (101) due to can be reduced.

The embodiments and examples disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

For example, in the first and second embodiments described above, an example in which the pair of rails 21g are formed on the base plate 21 so as to extend along the vibration direction of the movable portion 3, but the present invention is not limited thereto. For example, three or more rails may be formed. Further, the rail may be formed to extend in a direction inclined by a predetermined angle from the vibration direction of the movable part.

In the first and second embodiments, the example in which the rail 21g is integrally formed with the base plate 21 has been shown, but the present invention is not limited to this. That is, a rail made of another member may be fixed to the base plate 21 by adhesion or the like.

Further, in the first and second embodiments, the example in which the surface of the rail 21g is subjected to the fluororesin processing is shown, but the present invention is not limited to this, and the fluororesin processing may not be performed.

In the first and second embodiments, the movable member 3 (103) is movably supported by the spring member 4 (104). However, the present invention is not limited to this, and a coil spring or a rubber member is used. An elastic member other than the leaf spring may be used.

Further, in the first and second embodiments, the example in which the yoke-integrated coil portion 24 on which the

planar coils

25 and 26 are disposed is disposed only on one surface side of the movable portion 3 (103) is shown. The invention is not limited to this, and it may be arranged on both surfaces of the movable portion 3 (103). Thereby, since it drives from the both sides of the movable part 3 (103), the driving force of the movable part 3 (103) can be improved. As a result, the response time of the movable part 3 (103) (time until the movable part 3 (103) reaches a predetermined vibration amount) can be shortened.

In the second embodiment, the rail 21g is provided on the base plate 21 and the sliding portion 133a of the magnet cover 133 is slid on the rail 21g. However, the present invention is not limited to this. That is, like the magnet cover 633 of the vibration motor of the first modified example of the second embodiment shown in FIG. 16, the base plate 21 is provided with a protrusion 633b protruding downward (base plate side) on the sliding portion 633a of the magnet cover 633. It is good also as a structure which does not provide a rail. Also by this, the contact area between the base plate 21 and the magnet cover 133 can be reduced.

In the second embodiment, the example using the spring member 104 having the folded portion 142b is shown. However, the present invention is not limited to this, and the vibration motor of the second modification of the second embodiment shown in FIG. Like the spring member, the resin 600 may be applied to the inner portion of the folded portion 142b. Thereby, the stress generated in the folded portion 142b by the resin 600 can be dispersed and the load can be reduced, so that the reliability of the spring member 104 can be improved.

In the first and second embodiments, the example in which the opening 41a (141a) is provided in the plate 41 (141) of the spring member 4 (104) is shown, but the present invention is not limited to this. In the first and second embodiments, the spring member 4 (104) is made of non-magnetic SUS. However, since the SUS may become magnetic when the spring member is processed, the magnetic dish portion. In order to prevent the magnetism from being shielded by 41 (141), an opening 41a (141a) is provided. Therefore, if the spring member is a material that does not have magnetism, the spring member need not be provided with an opening. When the protrusion is provided as in the second embodiment, the opening 700a is provided only in the region corresponding to the protrusion, as in the spring member 700 of the vibration motor of the third modification of the second embodiment shown in FIG. It may be formed.

In the first and second embodiments, an example in which the case 23 and the magnet cover 33 (133) are subjected to the Nimflon treatment has been shown, but the present invention is not limited to this. That is, normal Teflon coating (lining) treatment may be performed. Moreover, as fluororesin processing, not only PTFE but other fluororesins may be used.

In the first and second embodiments, the case 23 (base plate 21 and upper case portion 22) is made of a magnetic material and used as a yoke. However, the present invention is not limited to this. That is, even when the case is made of a non-magnetic material, the case covers the surface of the case (in particular, the upper surface (outer surface or inner surface) and the lower surface (outer surface or inner surface)) of the case. A yoke made of a separate magnetic material may be fixed.

In the first embodiment, the example in which the movable member 3 is supported by the spring member 4 so as not to contact the case 23 is shown. However, the present invention is not limited to this, and the movable member 3 contacts the case 23. You may let them. By bringing the movable part into contact (sliding) with the case (rail), the Q value of the vibration system of the vibration motor can be lowered by friction between the movable part and the rail. Thereby, the vibration of the movable part can be stabilized and the stop characteristic of the vibration can be improved. Further, the Q value of the vibration system of the vibration motor can be reduced by breaking the balance of the suction force in the vertical direction of the movable part between the yoke and the upper case part without contacting (sliding) the movable part and the rail. Can be lowered.

In the first and second embodiments, the example in which the width W3 in the X direction of the yoke-integrated coil portion 24 is larger than the width W2 in the X direction of the permanent magnet 31 has been described, but the present invention is not limited thereto. The width W3 in the X direction of the yoke-integrated coil portion 24 may be smaller than the width W2 in the X direction of the permanent magnet 31.

In the first and second embodiments, the example in which the permanent magnet 31 is configured by the N pole surface 311a, the S pole surface 312a, the S pole surface 311b, and the N pole surface 312b has been described. However, the present invention is not limited to this. I can't. For example, the permanent magnet 31 may be composed of only the N pole surface 311a and the S pole surface 312a, and the S pole surface 311b and the N pole surface 312b may not be provided. That is, it is only necessary to provide magnetic pole surfaces magnetized with different magnetism along the surfaces facing the

planar coils

25 and 26.

In the first and second embodiments, the example in which the movable portion 3 (103) does not include a yoke (magnetic body) has been described. However, the present invention is not limited to this, and the movable portion 3 (103) has a yoke ( (Magnetic material) may be disposed. In this case, it is preferable that the yoke provided in the movable portion is arranged so as not to be positioned between the permanent magnet and the upper surface side yoke or between the permanent magnet and the lower surface side yoke.

Moreover, although the example which provided the magnet cover 33 (133) was shown in the said 1st and 2nd embodiment, this invention is not restricted to this, If the permanent magnet 31 and the weight 32 are assembled | attached as an integral object. The magnet cover may not be provided.

1, 101 Vibration motor 2 Fixing part 21 Base plate (lower side yoke)
22 Upper case (upper side yoke)
23 Case 24 Yoke-integrated

coil section

25, 26 Planar coil (coil)
28 Yoke (lower side yoke)
3, 103 Movable part 31

Permanent magnet

33, 133

Magnet cover

4, 104

Spring member

41, 141 Dish part (attachment part)

Claims

A movable part including a permanent magnet;
A coil that is arranged to face the movable part and generates a magnetic force that moves the movable part when energized;
A fixed portion including an upper surface side yoke and a lower surface side yoke disposed on both the upper surface side and the lower surface side of the movable portion so as to face the movable portion so as to sandwich the movable portion and the coil, respectively. Equipped with vibration motor.
The force with which the movable part is attracted to the upper surface side of the movable part by the upper surface side yoke cancels out at least a part of the force with which the movable part is attracted to the lower surface side of the movable part by the lower surface side yoke. The vibration motor according to claim 1, which acts on the motor.
The vibration motor according to claim 1 or 2, wherein the coil is disposed on either the upper surface side or the lower surface side of the movable portion.
A spring member that movably supports the movable part in a direction along the upper surface of the coil;
The spring member includes an attachment portion fixed to the movable portion so as to cover an upper surface of the movable portion,
The vibration motor according to claim 3, wherein the attachment portion has an opening.
The vibration motor according to any one of claims 1 to 4, wherein the movable part includes a magnet cover that supports the permanent magnet and is made of a nonmagnetic material.