Vibration motor

Abstract

A cylindrical holder (30) has, in a flange part (321), an opening part (OP321) that communicates with a through hole (300) and has a larger diameter than the through hole (300). The cylindrical holder (30) has, in a flange part (322), an opening part (OP322) that communicates with the through hole (300) and has a larger diameter than the through hole (300). A stator magnet (51) is fitted into the opening part (OP321) and fixed to the cylindrical holder (30). A stator magnet (52) is fitted into the opening part (OP322) and fixed to the cylindrical holder (30). The center of the stator magnet (51) fitted into the opening part (OP321) and the center of the stator magnet (52) fitted into the opening part (OP322) are shifted in the same direction with respect to the center of the through hole (300).

Description

Vibration motor

[0001] The present invention relates to a vibration motor having a configuration in which a mover magnet is housed in a cylindrical holder so that it can vibrate.

[0002] Patent Document 1 describes a linear vibration motor. The linear vibration motor of Patent Document 1 has a configuration in which a mover magnet is supported by two shafts. The linear vibration motor of Patent Document 1 uses the gravity of the mover magnet to press the mover magnet against the shafts. This makes the linear vibration motor of Patent Document 1 quieter.

[0003] JP 2024-17840 A

[0004] However, in conventional linear vibration motors such as those shown in Patent Document 1, when the mounting surface of the linear vibration motor is taken into consideration, the direction perpendicular to the plane defined by the two shafts and whether it faces upward or downward is uniquely determined. On the other hand, in the case of cylindrical motors, the mover magnet is not plate-shaped, and the mounting orientation is not determined, so the magnet must be arranged to suppress noise regardless of the direction of gravity. Furthermore, conventional linear vibration motors such as those shown in Patent Document 1 have many components because they use shafts.

[0005] SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a vibration motor that can be made quieter with fewer components.

[0006] A vibration motor according to one embodiment of the present invention includes a mover magnet, first and second stator magnets, a cylindrical holder having a through hole with both ends open and having flanges on at least both ends of its outer surface, a drive winding disposed on the outer surface of the cylindrical holder and wound in a recess formed between the flanges on both ends, and a case housing the cylindrical holder and the drive winding. The mover magnet is housed in the through hole in a state in which it can vibrate in a first direction parallel to the axis of the through hole. The first and second stator magnets are arranged to sandwich the mover magnet between them in the first direction, and their magnetic poles are arranged to repel the mover magnet.

[0007] The cylindrical holder has a first opening in one of the flanges at both ends that communicates with the through hole and has a diameter larger than that of the through hole. The cylindrical holder has a second opening in the other of the flanges at both ends that communicates with the through hole and has a diameter larger than that of the through hole. The first stator magnet is fitted into the first opening and fixed to the cylindrical holder. The second stator magnet is fitted into the second opening and fixed to the cylindrical holder. The center of the first stator magnet fitted into the first opening and the center of the second stator magnet fitted into the second opening are offset in the same direction relative to the center of the through hole.

[0008] In this configuration, the repulsive forces acting on the mover magnet from the first stator magnet fitted in the first opening and the second stator magnet fitted in the second opening include a component directed toward the inner circumferential surface of the through-hole, which causes the mover magnet to always be pressed against the inner circumferential surface of the through-hole in the same direction, suppressing rattling of the mover magnet when it vibrates.

[0009] A vibration motor according to one embodiment of the present invention includes a mover magnet, a first stator magnet, a second stator magnet, a cylindrical holder having a through hole with both ends open and a plurality of flanges on its outer surface, a drive winding disposed on the outer surface of the cylindrical holder and wound in a recess formed between the plurality of flanges, and a case for housing the cylindrical holder and the drive winding. The mover magnet is housed in the through hole in a state in which it can vibrate in a first direction parallel to the axis of the through hole. The first stator magnet and the second stator magnet are disposed so as to sandwich the mover magnet between them in the first direction, and their magnetic poles are arranged so as to repel the mover magnet.

[0010] The case has a first recess formed at a position facing one end of the cylindrical holder and a second recess formed at a position facing the other end of the cylindrical holder. The first stator magnet is fitted into the first recess and fixed to the case. The second stator magnet is fitted into the second recess and fixed to the case. The centers of the first stator magnet fitted into the first recess and the second stator magnet fitted into the second recess are offset in the same direction from the center of the through hole.

[0011] In this configuration, the repulsive forces acting on the mover magnet from the first stator magnet fitted in the first recess and the second stator magnet fitted in the second recess include a component directed toward the inner circumferential surface of the through-hole, which causes the mover magnet to always be pressed against the inner circumferential surface of the through-hole in the same direction, suppressing rattling of the mover magnet when it vibrates.

[0012] According to this invention, noise reduction can be achieved with fewer components.

[0013] FIG. 1 is a cross-sectional view showing an example of the configuration of a vibration motor according to a first embodiment. FIG. 2 is an exploded perspective view showing an example of the configuration of a vibration motor according to the first embodiment. FIG. 3(A) is a side view of a cylindrical holder, FIG. 3(B) is a front view of the second end of the cylindrical holder, FIG. 3(C) is a front view of the first end of the cylindrical holder, and FIG. 3(D) is a cross-sectional view of the cylindrical holder. FIGS. 4(A), 4(B), 4(C), and 4(D) are diagrams showing an example of the position of a mover magnet and the repulsive force acting thereon. FIG. 5 is a graph showing an example of a simulation result of electromagnetic force and gravity relative to the position of the mover magnet. FIGS. 6(A), 6(B), and 6(C) are perspective views showing the configuration of a vibration motor during the manufacturing process. FIG. 7 is a cross-sectional view showing an example of the configuration of a vibration motor according to a second embodiment. FIG. 8 is a cross-sectional view showing an example of the configuration of a vibration motor according to a third embodiment. FIGS. 9(A) and 9(B) are cross-sectional views showing examples of alternative examples of mover magnets. Fig. 10 is a cross-sectional view showing an example of another embodiment of the cylindrical holder and the drive winding. Fig. 11(A), Fig. 11(B), and Fig. 11(C) are schematic diagrams showing an example of another embodiment of the wiring of the drive winding.

[0014] [First embodiment] A vibration motor according to a first embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a cross-sectional view showing an example of the configuration of a vibration motor according to the first embodiment. Fig. 2 is an exploded perspective view showing an example of the configuration of a vibration motor according to the first embodiment.

[0015] 1 and 2, the vibration motor 10 includes a case 20, a cylindrical holder 30, a drive winding 41, a drive winding 42, a stator magnet 51, a stator magnet 52, and a mover magnet 60. The stator magnet 51 corresponds to the first stator magnet, and the stator magnet 52 corresponds to the second stator magnet.

[0016] The case 20 includes a first housing 21 and a second housing 22. The first housing 21 is made of insulating resin, and the second housing 22 is made of metal. However, the materials of the first housing 21 and the second housing 22 are not limited to this combination.

[0017] The first housing 21 is a box-shaped body with an opening, and has an internal space 210. The internal space 210 is cylindrical. The first housing 21 has a bottom surface BF21 on the side opposite to the opening side of the internal space 210.

[0018] The second housing 22 is a box-shaped body with an opening, and has an internal space 220. The internal space 220 is cylindrical. The second housing 22 has a bottom surface BF22 on the side opposite to the opening side of the internal space 220.

[0019] The first housing 21 and the second housing 22 are arranged so that their openings face each other, thereby forming an internal space in which the internal space 210 and the internal space 220 communicate with each other.

[0020] Fig. 3(A) is a side view of the cylindrical holder, Fig. 3(B) is a front view of the second end side of the cylindrical holder, Fig. 3(C) is a front view of the first end side of the cylindrical holder, and Fig. 3(D) is a cross-sectional view of the cylindrical holder.

[0021] The cylindrical holder 30 includes a main body 31, a flange 310, a flange 321, and a flange 322. The cylindrical holder 30 is made of a non-magnetic material.

[0022] The main body 31 is cylindrical and has a through hole 300 that penetrates from the first end to the second end. The direction in which the through hole 300 extends (the direction connecting the first end and the second end) is defined as a first direction. The through hole 300 has a constant diameter from the first end to the second end.

[0023] The flanges 310, 321, and 322 are annular and are disposed on the outer circumferential surface of the main body 31, protruding from the outer circumferential surface.

[0024] The flange 310 is positioned to include a middle position in the first direction of the main body 31. The flange 321 is positioned to include a first end of the main body 31. The flange 322 is positioned to include a second end of the main body 31.

[0025] The flange 310 and the flange 321 are disposed at a predetermined distance in the first direction. The flange 310 and the flange 322 are disposed at a predetermined distance in the first direction.

[0026] The flange portion 321 has an opening OP321 that opens to the first end side of the main body 31. The opening OP321 communicates with the through hole 300. The diameter of the opening OP321 is larger than the diameter of the through hole 300. When viewed in the first direction, the outer diameter of the opening OP321 is located outside the outer diameter of the through hole 300 (see FIG. 3C ). The opening OP321 corresponds to the first opening.

[0027] The flange portion 322 has an opening OP322 that opens to the second end side of the main body 31. The opening OP322 communicates with the through hole 300. The diameter of the opening OP322 is larger than the diameter of the through hole 300. When viewed in the first direction, the outer diameter of the opening OP322 is located outside the outer diameter of the through hole 300 (see FIG. 3B ). The opening OP322 corresponds to the second opening.

[0028] The openings OP321 and OP322 have the same diameter. The centers of the openings OP321 and OP322 are offset from the center of the through-hole 300 when viewed in the first direction.

[0029] More specifically, the center of the opening OP321 and the center of the opening OP322 are coaxial in the first direction. The opening central axis passing through the center of the opening OP321 and the center of the opening OP322 is at a position different from the central axis AX30 of the through hole 300.

[0030] The drive windings 41 and 42 each have a cylindrical shape formed by winding a linear conductor. The drive windings 41 and 42 are arranged along the outer circumferential surface of the main body 31 of the cylindrical holder 30. The drive winding 41 is arranged in a recess formed between the flanges 310 and 321. The drive winding 42 is arranged in a recess formed between the flanges 310 and 322.

[0031] The drive winding 41 is connected to a terminal conductor OL41 that protrudes from the case 20 to the outside. The drive winding 42 is connected to a terminal conductor OL42 that protrudes from the case 20 to the outside.

[0032] The stator magnets 51, 52, and mover magnet 60 are made of permanent magnets having ferromagnetic properties. For example, the stator magnets 51, 52, and mover magnet 60 are made of neodymium magnets.

[0033] The stator magnets 51, 52, and mover magnet 60 are cylindrical. The diameters of the stator magnets 51 and 52 are larger than the diameter of the mover magnet 60.

[0034] The diameter of the stator magnet 51 is approximately the same as the diameter of the opening OP321, but is equal to or smaller than the diameter of the opening OP321. In this case, the difference between the radius of the stator magnet 51 and the radius of the opening OP321 is smaller than the difference between the central axis of the opening and the central axis AX30 of the through hole 300.

[0035] The stator magnet 51 is fitted into the opening OP321 and fixed to the cylindrical holder 30. The fixing method may be simply fitting, or may be bonding with an adhesive.

[0036] The diameter of the stator magnet 52 is approximately the same as the diameter of the opening OP322, but is equal to or smaller than the diameter of the opening OP322. In this case, the difference between the radius of the stator magnet 52 and the radius of the opening OP322 is smaller than the difference between the central axis of the opening and the central axis AX30 of the through hole 300.

[0037] The stator magnet 52 is fitted into the opening OP322 and fixed to the cylindrical holder 30. The fixing method may be simply fitting, or may be bonding with an adhesive.

[0038] The diameter of the mover magnet 60 is approximately the same as the diameter of the through hole 300, but is smaller than the diameter of the through hole 300. The mover magnet 60 is housed in the through hole 300 of the cylindrical holder 30 in a state in which it can vibrate (slide) in the first direction.

[0039] In this case, the stator magnet 51 and the mover magnet 60 are arranged so that the same magnetic poles face each other. Furthermore, the stator magnet 52 and the mover magnet 60 are arranged so that the same magnetic poles face each other.

[0040] 1 , the mover magnet 60 is arranged so that its north pole face 60N faces the stator magnet 51 (the first end of the cylindrical holder 30) and its south pole face 60S faces the stator magnet 52 (the second end of the cylindrical holder 30).

[0041] The stator magnet 51 is arranged so that its north pole face 51N faces the mover magnet 60. The stator magnet 51 is arranged so that its south pole face 51S faces outward from the first end of the main body 31 along the first direction. This positions the stator magnet 51 so that it generates a repulsive force due to magnetic force with respect to the mover magnet 60.

[0042] The stator magnet 52 is arranged so that its south pole face 52S faces the mover magnet 60. The stator magnet 52 is arranged so that its north pole face 52N faces outward from the second end of the main body 31 along the first direction. This positions the stator magnet 52 so that it generates a repulsive force due to magnetic force with respect to the mover magnet 60.

[0043] The cylindrical holder 30, to which the drive windings 41, 42, the stator magnets 51, 52, and the mover magnet 60 are attached, is housed in the internal space of the case 20, which is made up of the internal space 210 of the first housing 21 and the internal space 220 of the second housing 22. At this time, a first end of the cylindrical holder 30 in the first direction abuts against the bottom surface BF21 of the first housing 21. A second end of the cylindrical holder 30 in the first direction abuts against the bottom surface BF22 of the second housing 22. The terminal conductors OL41 and OL42 are drawn to the outside of the case 20 through a gap on the side where the first housing 21 and the second housing 22 meet.

[0044] In this configuration, an AC drive signal is applied to the drive windings 41 and 42. This causes the drive windings 41 and 42 to excite an electromagnetic field. This electromagnetic field acts on the mover magnet 60, causing the mover magnet 60 to move in the first direction of the cylindrical holder 30.

[0045] At this time, the mover magnet 60 receives a magnetic repulsive force from the stator magnets 51 and 52 at both ends in the first direction, causing the mover magnet 60 to vibrate along the first direction. Therefore, the vibration motor 10 can generate vibrations using the magnetic spring mechanism.

[0046] This vibration is transmitted to the case 20 , and the vibration motor 10 can apply vibration to an object or person that comes into contact with the case 20 .

[0047] In the vibration motor 10 configured as described above, the center of the opening OP321 and the center of the opening OP322 are offset in the same direction from the center of the through-hole 300. The through-hole 300 houses the mover magnet 60. The stator magnet 51 is fixed to the opening OP321. The stator magnet 52 is fixed to the opening OP322.

[0048] As a result, the centers of stator magnets 51 and 52 are offset from the center of mover magnet 60. More specifically, the center of mover magnet 60 exists on the central axis AX30 of through-hole 300. The central axis AX50 connecting the centers of stator magnets 51 and 52 coincides with the central axis of the opening.

[0049] Therefore, the central axis through which the center of mover magnet 60 approximately passes when it vibrates is at a different position from central axis AX50 connecting the centers of stator magnets 51 and 52. Furthermore, central axis AX50 connecting the centers of stator magnets 51 and 52 is shifted to the same side with respect to central axis AX30 about which mover magnet 60 vibrates, regardless of the position of mover magnet 60 in the first direction.

[0050] In this configuration, the following repulsive forces act on the mover magnet 60. Figure 4 is a diagram showing an example of the position of the mover magnet and the repulsive forces acting on it. Figure 4(A) is a cross-sectional view of the mover magnet in the center in the first direction, Figure 4(B) is a cross-sectional view of the mover magnet in the vicinity of the second end in the first direction, and Figure 4(D) is a diagram showing the repulsive forces when the mover magnet is in the vicinity of the second end in the first direction.

[0051] 4(A) and 4(B), when mover magnet 60 is in the center in the first direction (the center of through-hole 300), mover magnet 60 receives repulsive force FB51c from stator magnet 51. Repulsive force FB51c has a component in the first direction (a component toward the second end) and a component in a direction in which central axis AX50 deviates from central axis AX30.

[0052] Furthermore, when mover magnet 60 is in the center in the first direction (the center of through-hole 300), mover magnet 60 receives a repulsive force FB52c from stator magnet 52. Repulsive force FB52c has a component in the first direction (a component toward the first end) and a component in a direction in which central axis AX50 deviates from central axis AX30.

[0053] The resultant force of repulsive forces FB51c and FB52c acts on mover magnet 60. Repulsive forces FB51c and FB52c each have a component in a direction in which central axis AX50 deviates from central axis AX30. Therefore, a force F60c (component perpendicular to the inner wall surface) acts on mover magnet 60, directed toward the surface of inner wall surface FI31 of through hole 300 in a direction in which central axis AX50 deviates from central axis AX30.

[0054] This force F60c presses the mover magnet 60 against the surface of the inner wall surface FI31 of the through-hole 300 in a direction in which the central axis AX50 is offset from the central axis AX30.

[0055] 4(C) and 4(D), when mover magnet 60 is in the vicinity of the second end in the first direction, mover magnet 60 receives a repulsive force FB51e from stator magnet 51. Repulsive force FB51e has a component in the first direction (a component toward the second end) and a component in a direction in which central axis AX50 deviates from central axis AX30.

[0056] Furthermore, when mover magnet 60 is in the vicinity of the second end in the first direction, mover magnet 60 receives a repulsive force FB52e from stator magnet 52. Repulsive force FB52e has a component in the first direction (a component toward the first end) and a component in a direction in which central axis AX50 deviates from central axis AX30.

[0057] The resultant force of repulsive forces FB51e and FB52e acts on mover magnet 60. Repulsive forces FB51e and FB52e each have a component in a direction in which central axis AX50 deviates from central axis AX30. Therefore, force F60e acts on mover magnet 60, including a force F60ev (a component perpendicular to the inner wall surface) directed toward the surface of inner wall surface FI31 of through hole 300 in a direction in which central axis AX50 deviates from central axis AX30.

[0058] This force F60ev presses the mover magnet 60 against the surface of the inner wall surface FI31 of the through-hole 300 in a direction in which the central axis AX50 is deviated from the central axis AX30.

[0059] Furthermore, the force F60c when the mover magnet 60 is in the center of the first direction (the center of the through hole 300) and the force F60ev when the mover magnet 60 is near the second end of the first direction are directed in the same direction.

[0060] Furthermore, although not shown, no matter where mover magnet 60 is in the first direction, forces in the same directions as the above-mentioned forces F60c and F60ev act on mover magnet 60. Therefore, while mover magnet 60 is vibrating in the first direction, it is constantly pressed against the surface of inner wall surface FI31 in a direction in which central axis AX50 is deviated from central axis AX30.

[0061] This suppresses rattles caused by vibration of the mover magnet 60. Therefore, the vibration motor 10 can be made quieter.

[0062] In this case, the vibration motor 10 can suppress rattles caused by vibration of the mover magnet 60 using only the minimum number of components required to vibrate the mover magnet 60 in the first direction. Therefore, the vibration motor 10 can achieve quiet operation with a small number of components.

[0063] Furthermore, the vibration motor 10 makes the force (electromagnetic force) acting on the movable magnet 60 in the direction of shifting the central axis AX50 from the central axis AX30 greater than the gravity (mg in Figures 4(A) and 4(C)) acting on the movable magnet 60.

[0064] 5 is a graph showing an example of the simulation results of electromagnetic force and gravity versus the position of the mover magnet. The vertical axis of the graph represents the magnitude of gravity and electromagnetic force, and the horizontal axis of the graph represents the position in the vibration direction of the stator magnet. The solid line represents electromagnetic force, and the dotted line represents gravity.

[0065] As shown in FIG. 5, regardless of the position of the mover magnet 60, the electromagnetic force (the force pressing the mover magnet 60 against the inner wall surface F131) exceeds gravity.

[0066] This allows the mover magnet 60 to always abut against the inner wall surface FI31 regardless of the posture of the vibration motor 10 during use. Therefore, the vibration motor 10 can be made quieter without being affected by the posture.

[0067] Furthermore, the vibration motor 10 may have oil inserted into the through-hole 300 of the cylindrical holder 30 to improve the sliding properties. This improves the sliding properties even if a force is constantly applied to the mover magnet 60 pressing against the inner wall surface FI31, thereby improving the characteristics of the vibration motor 10.

[0068] At this time, as described above, the stator magnet 51 is fixed to the opening OP321 with an adhesive, and the stator magnet 52 is fixed to the opening OP322 with an adhesive, so that both ends of the through hole 300 are sealed by the stator magnets 51 and 52. Therefore, the vibration motor 10 can prevent oil leakage. In particular, if the diameter of the stator magnet 51 is the same as the diameter of the opening OP321 and the diameter of the stator magnet 52 is the same as the diameter of the opening OP322, sealing performance is improved.

[0069] The vibration motor 10 having the above-described configuration is manufactured, for example, as follows: Figures 6(A), 6(B), and 6(C) are perspective views showing the configuration of the vibration motor during the manufacturing process.

[0070] First, as shown in Fig. 6A, the drive windings 41 and 42 are attached to the cylindrical holder 30. Next, as shown in Fig. 6B, the mover magnet 60 is inserted into the through-hole 300 of the cylindrical holder 30.

[0071] 6(C), the stator magnet 51 is attached to the opening OP321, and the stator magnet 51 is adhered and fixed to the cylindrical holder 30 with an adhesive. Similarly, the stator magnet 52 is attached to the opening OP322, and the stator magnet 52 is adhered and fixed to the cylindrical holder 30 with an adhesive.

[0072] The cylindrical holder 30, to which the drive windings 41, 42, the stator magnets 51, 52, and the mover magnet 60 are attached, is covered with a case 20 made up of a first housing 21 and a second housing 22. With this configuration, the vibration motor 10 can be manufactured.

[0073] Second Embodiment A vibration motor according to a second embodiment of the present invention will be described with reference to the drawings. Fig. 7 is a cross-sectional view showing an example of the configuration of a vibration motor according to the second embodiment.

[0074] 7, the vibration motor 10A according to the second embodiment differs from the vibration motor 10 according to the first embodiment in that the stator magnets 51 and 52 are positioned by a case 20A. The other configuration of the vibration motor 10A is the same as that of the vibration motor 10, and a description of similar parts will be omitted.

[0075] The vibration motor 10A includes a case 20A and a cylindrical holder 30A. The case 20A includes a first housing 21A and a second housing 22A. The first housing 21A and the second housing 22A are made of, for example, insulating resin.

[0076] The first housing 21A has an internal space 210A and a bottom surface BF21. The first housing 21A has a recess 211A recessed from the bottom surface BF21. The shape of the recess 211A when viewed from the opening (when viewed in the first direction) is the same as that of the stator magnet 51.

[0077] The second housing 22A has an internal space 220A and a bottom surface BF22. The second housing 22A has a recess 221A recessed from the bottom surface BF22. The shape of the recess 221A when viewed from the opening (when viewed in the first direction) is the same as that of the stator magnet 52.

[0078] The cylindrical holder 30A includes a main body 31, a flange 310, a flange 321A, and a flange 322A. The main body 31 and the flange 310 of the cylindrical holder 30A have the same configuration as the cylindrical holder 30.

[0079] The flange 321A is disposed on the first end side of the main body 31 relative to the flange 310, and is disposed at a predetermined distance from the first end toward the flange 310.

[0080] The flange 322A is disposed on the second end side of the main body 31 relative to the flange 310, and is disposed at a predetermined distance from the second end toward the flange 310.

[0081] The stator magnet 51 is housed in the recess 211A and fixed to the first housing 21A. The stator magnet 52 is housed in the recess 221A and fixed to the second housing 22A. The fixing method may be simply to house the magnet in the recess, or may be to adhere the magnet with an adhesive.

[0082] The cylindrical holder 30A, on which the drive windings 41, 42, and mover magnet 60 are mounted, is housed in a first housing 21A, on which the stator magnet 51 is mounted, and a second housing 22A, on which the stator magnet 52 is mounted. At this time, the stator magnet 51 abuts against a first end of the cylindrical holder 30A, and the stator magnet 52 abuts against a second end of the cylindrical holder 30A. Furthermore, the flange 321A abuts against a bottom surface BF21 of the internal space 210A, and the flange 322A abuts against a bottom surface BF22 of the internal space 220A.

[0083] In the vibration motor 10A configured as described above, the center of the recess 211A and the center of the recess 221A are offset in the same direction from the center of the through-hole 300. The mover magnet 60 is housed in the through-hole 300. The stator magnet 51 is fixed to the recess 211A. The stator magnet 52 is fixed to the recess 221A.

[0084] As a result, the centers of stator magnets 51 and 52 are offset from the center of mover magnet 60. More specifically, the center of mover magnet 60 exists on central axis AX30 of through-hole 300. Central axis AX50A connecting the centers of stator magnets 51 and 52 coincides with the recess central axis connecting the centers of recesses 211A and 221A.

[0085] Therefore, the central axis through which the center of mover magnet 60 approximately passes when it vibrates is at a different position from central axis AX50A connecting the centers of stator magnets 51 and 52. Furthermore, central axis AX50A connecting the centers of stator magnets 51 and 52 is shifted to the same side with respect to central axis AX30 about which mover magnet 60 vibrates, regardless of the position of mover magnet 60 in the first direction.

[0086] With this configuration, similar to vibration motor 10, vibration motor 10A is always pressed against a surface in a direction in which the center axis AX50 of inner wall surface FI31 is shifted from center axis AX30, regardless of the position of movable magnet 60 in the first direction.

[0087] This suppresses rattles caused by vibration of the mover magnet 60. Therefore, the vibration motor 10A can achieve quieter operation.

[0088] [Third Embodiment] A vibration motor according to a third embodiment of the present invention will be described with reference to the drawings. Fig. 8 is a cross-sectional view showing an example of the configuration of a vibration motor according to the third embodiment.

[0089] 8, the vibration motor 10B according to the third embodiment differs from the vibration motor 10 according to the first embodiment in the sizes of the stator magnets 51 and 52 and the arrangement of the stator magnets 51 and 52. The other configuration of the vibration motor 10B is the same as that of the vibration motor 10, and a description of similar parts will be omitted.

[0090] The vibration motor 10B includes a case 20B, a cylindrical holder 30B, a stator magnet 51, and a stator magnet 52.

[0091] The outer shapes of the stator magnets 51 and 52 are smaller than the outer shapes of the mover magnets 60. More specifically, the diameters of the stator magnets 51 and 52 are smaller than the diameter of the mover magnets 60.

[0092] The case 20B includes a first housing 21B and a second housing 22B. The first housing 21B and the second housing 22B are made of, for example, insulating resin.

[0093] The first housing 21B has an internal space 210B, a bottom surface BF21, a recess 211B, a recess bottom surface BF210, and a recess 212B.

[0094] The recess 211B has a shape recessed from a bottom surface BF21 that defines the internal space 210B. The shape of the recess 211B when viewed from the opening (when viewed in the first direction) is the same as the outer shape of the main body 31 of the cylindrical holder 30. The recess 211B has a recess bottom surface BF210.

[0095] The recess 212B has a shape recessed from the recess bottom surface BF210. The shape of the recess 212B when viewed from the opening (when viewed in the first direction) is the same as that of the stator magnet 51.

[0096] The second housing 22B has an internal space 220B, a bottom surface BF22, a recess 221B, a recess bottom surface BF220, and a recess 222B.

[0097] The recess 221B has a shape recessed from a bottom surface BF22 that defines the internal space 220B. The shape of the recess 221B when viewed from the opening (when viewed in the first direction) is the same as the outer shape of the main body 31 of the cylindrical holder 30. The recess 221B has a recess bottom surface BF220.

[0098] The recess 222B has a shape recessed from the recess bottom surface BF220. The shape of the recess 222B when viewed from the opening (when viewed in the first direction) is the same as that of the stator magnet 52.

[0099] The cylindrical holder 30B includes a main body 31, a flange 310, a flange 321B, and a flange 322B. The cylindrical holder 30B has the same configuration as the cylindrical holder 30A according to the second embodiment.

[0100] The stator magnet 51 is housed in the recess 212B and fixed to the first housing 21B. In this case, the surface of the stator magnet 51 on the inner space 210B side is located closer to the recess 212B than the recess bottom surface BF210.

[0101] The stator magnet 52 is housed in the recess 222B and fixed to the second housing 22B. In this case, the surface of the stator magnet 52 on the side of the internal space 220B is recessed closer to the recess 222B than the recess bottom surface BF220.

[0102] The cylindrical holder 30B, on which the drive winding 41, the drive winding 42, and the mover magnet 60 are mounted, is housed in a first housing 21B, on which the stator magnet 51 is mounted, and a second housing 22B, on which the stator magnet 52 is mounted.

[0103] At this time, the first end of the body 31 of the cylindrical holder 30B contacts the recess bottom surface BF210, and the flange 321B contacts the bottom surface BF21. Also, the second end of the body 31 of the cylindrical holder 30B contacts the recess bottom surface BF220, and the flange 322B contacts the bottom surface BF22.

[0104] The centers of recesses 212B and 222B are offset in the same direction from the center of through-hole 300. Mover magnet 60 is housed in through-hole 300. Stator magnet 51 is fixed in recess 212B. Stator magnet 52 is fixed in recess 222B.

[0105] As a result, the centers of stator magnets 51 and 52 are offset from the center of mover magnet 60. More specifically, the center of mover magnet 60 exists on central axis AX30 of through-hole 300. Central axis AX50A connecting the centers of stator magnets 51 and 52 coincides with the recess central axis connecting the centers of recesses 212B and 222B.

[0106] Therefore, the central axis through which the center of mover magnet 60 approximately passes when it vibrates is at a different position from the central axis AX50B connecting the centers of stator magnets 51 and 52. Furthermore, regardless of the position of mover magnet 60 in the first direction, central axis AX50B connecting the centers of stator magnets 51 and 52 is shifted to the same side with respect to central axis AX30 about which mover magnet 60 vibrates.

[0107] With this configuration, similar to vibration motors 10 and 10A, vibration motor 10B is always pressed against a surface in a direction in which the center axis AX50 of inner wall surface FI31 is shifted from center axis AX30, regardless of the position of movable magnet 60 in the first direction.

[0108] This suppresses rattles caused by vibration of the mover magnet 60. Therefore, the vibration motor 10B can achieve quieter operation.

[0109] Furthermore, in the vibration motor 10B, the stator magnet 51 fits into the recess 212B, and the stator magnet 52 fits into the recess 222B.

[0110] The area of ​​the mover magnet 60 in the moving direction (the area when viewed in the first direction) is larger than the opening area of ​​the recess 212B and the opening area of ​​the recess 222B. Therefore, even if a voltage higher than expected is applied to the drive windings 41 and 42, causing the acceleration of the mover magnet 60 to increase too much and reach the end of the cylindrical holder 30 in the first direction, it is possible to prevent the mover magnet 60 from colliding with the stator magnet 51 or 52. This allows the vibration motor 10B to prevent damage to the mover magnet 60, stator magnet 51, and stator magnet 52.

[0111] (Alternative Embodiments of Mover Magnet) FIGS. 9(A) and 9(B) are cross-sectional views each showing an example of an alternative embodiment of the mover magnet.

[0112] 9A includes a plurality of magnets 601-603 (magnet 601, magnet 602, magnet 603). The plurality of magnets 601-603 are made up of permanent magnets, similar to the mover magnet 60 described above.

[0113] The multiple magnets 601-603 are attached together in the direction of attraction. Specifically, the south pole face 601S of magnet 601 is attached to the north pole face 602N of magnet 602. The south pole face 602S of magnet 602 is attached to the north pole face 603N of magnet 603. As a result, the north pole face 601N of magnet 601 becomes the north pole face 60N of mover magnet 60X1. Furthermore, the south pole face 603S of magnet 603 becomes the south pole face 60S of mover magnet 60X2.

[0114] The mover magnet 60X2 shown in FIG. 9B includes a plurality of magnets 601-602 (magnets 601 and 602) and a metal member 600M.

[0115] The plurality of magnets 601-602 are made up of permanent magnets, similar to the above-described mover magnet 60. The metal member 600M is made up of a metal with a greater specific gravity than the magnets 601-602. For example, the metal member 600M is made up of tungsten or the like.

[0116] Magnets 601 and 602 are arranged so as to sandwich metal member 600M. At this time, south pole face 601S of magnet 601 is attracted to metal member 600M. Also, north pole face 602N of magnet 602 is attracted to metal member 600M. As a result, north pole face 601N of magnet 601 becomes north pole face 60N of mover magnet 60X2. Also, south pole face 602S of magnet 602 becomes south pole face 60S of mover magnet 60X2.

[0117] (Alternative Forms of Cylindrical Holder and Drive Winding) FIG. 10 is a cross-sectional view showing an example of an alternative form of a cylindrical holder and a drive winding.

[0118] The cylindrical holder 30Y includes a plurality of auxiliary flanges 330 between the flanges 310 and 321 and between the flanges 310 and 322.

[0119] The drive winding 41Y1 is wound in a divided manner around a plurality of recesses formed by the flange portion 310, the flange portion 321, and a plurality of auxiliary flange portions 330 between the flange portion 310 and the flange portion 321.

[0120] The drive winding 41Y2 is wound in a divided manner around a plurality of recesses formed by the flange portion 310, the flange portion 322, and a plurality of auxiliary flange portions 330 between the flange portion 310 and the flange portion 322.

[0121] (Alternative Wiring of Drive Winding) FIGS. 11A, 11B, and 11C are schematic diagrams showing alternative wiring examples of the drive winding.

[0122] 11(A) and 11(B), the drive windings 41 and 42 are connected in parallel. The winding direction and connection method of the drive windings 41 and 42 are determined so that when a current is passed through them, the magnetic flux generated has the same polarity at the ends that are close to each other and the same polarity at the ends that are far apart.

[0123] 11(C), the drive windings 41 and 42 are connected in series. In this configuration, as in Figures 11(A) and 11(B), the winding direction is determined so that the magnetic flux generated when a current is passed through the windings has the same polarity at ends that are close to each other and the same polarity at ends that are far apart.

[0124] In this way, the drive windings 41 and 42 do not have to be configured to individually supply drive signals, but may be configured to supply drive signals by connecting them in parallel or in series.

[0125] <1> A vibration motor comprising: a mover magnet; a first stator magnet and a second stator magnet; a cylindrical holder having a through hole that is open at both ends and having flanges on at least both ends of its outer surface; a drive winding that is arranged on the outer circumferential surface of the cylindrical holder and wound in at least two recesses formed between the flanges provided on the both ends; and a case that houses the cylindrical holder and the drive winding, wherein the mover magnet is housed in the through hole in a state in which it can vibrate in a first direction parallel to the axis of the through hole, and the first stator magnet and the second stator magnet are arranged to sandwich the mover magnet therebetween in the first direction, and have magnetic poles that are repulsive to the mover magnet, wherein the cylindrical holder has a first opening in one of the flanges at both ends that communicates with the through hole and has a diameter larger than that of the through hole, a second opening in communication with the through hole and having a diameter larger than that of the through hole at the other end of the flanges; the first stator magnet is fitted into the first opening and fixed to the cylindrical holder; the second stator magnet is fitted into the second opening and fixed to the cylindrical holder; and the center of the first stator magnet fitted into the first opening and the center of the second stator magnet fitted into the second opening are offset in the same direction relative to the center of the through hole.

[0126] <2> A vibration motor comprising: a mover magnet; a first stator magnet and a second stator magnet; a cylindrical holder having a through hole that is open at both ends and has a plurality of flanges on its outer surface; a drive winding that is disposed on the outer circumferential surface of the cylindrical holder and wound in a recess formed between the plurality of flanges; and a case that accommodates the cylindrical holder and the drive winding, wherein the mover magnet is accommodated in the through hole in a state in which it can vibrate in a first direction parallel to the axis of the through hole, and the first stator magnet and the second stator magnet are arranged to sandwich the mover magnet therebetween in the first direction and have magnetic poles that repel the mover magnet, and the case has a first recess formed at a position facing one end of the cylindrical holder and a second recess formed at a position facing the other end of the cylindrical holder, and the first stator magnet is fitted into the first recess and fixed to the case, the second stator magnet is fitted into the second recess and fixed to the case, and the center of the first stator magnet fitted into the first recess and the center of the second stator magnet fitted into the second recess are offset in the same direction relative to the center of the through hole.

[0127] <3> The vibration motor according to <1>, wherein the first stator magnet and the second stator magnet are fixed to the cylindrical holder with an adhesive.

[0128] <4> The vibration motor according to <2>, wherein the first stator magnet and the second stator magnet are fixed to the case with an adhesive.

[0129] <5> The vibration motor according to any one of <1> to <4>, wherein the mover magnet is formed by bonding a plurality of permanent magnets together in directions in which they attract each other.

[0130] <6> The vibration motor according to <5>, wherein the mover magnet is formed by sandwiching a metal having a specific gravity greater than that of the permanent magnets between the plurality of permanent magnets.

[0131] <7> The vibration motor according to any one of <1> to <6>, wherein a center of the first stator magnet and a center of the second stator magnet are coaxial in the first direction.

[0132] <8> The vibration motor according to any one of <1> to <7>, wherein, regardless of the position of the mover magnet in the first direction, a component of a resultant force of a first repulsive force that the first stator magnet exerts on the mover magnet and a second repulsive force that the second stator magnet exerts on the mover magnet, which is perpendicular to the inner wall surface of the through hole, is greater than the gravity of the mover magnet.

[0133] DESCRIPTION OF SYMBOLS 10, 10A, 10B: vibration motor 20, 20A, 20B: case 21, 21A, 21B: first housing 22, 22A, 22B: second housing 30, 30A, 30B, 30Y: cylindrical holder 31: main body 41, 42: drive winding 51, 52: stator magnet 60, 60X1, 60X2: mover magnet 51N, 52N, 60N, 601N, 602N, 603N: north pole face 51S, 52S, 60S, 601S, 602S, 603S: south pole face 210, 210A, 210B, 220, 220A, 220B: internal space 211A, 211B, 212B, 221A, 221B, 222B: recess 300: Through hole 310, 321, 321A, 321B, 322, 322A, 322B: Flange portion 330: Auxiliary flange portion 601, 602, 603: Magnet 600M: Metal member AX30, AX50, AX50A, AX50B: Central axis BF21, BF22: Bottom surface BF210, BF220: Bottom surface of recess F60c, F60e, F60ev: Force FB51c, FB51e, FB52c, FB52e: Repulsive force FI31: Inner wall surface OL41, OL42: Terminal conductor OP321, OP322: Opening

Claims

1. A vibration motor comprising: a mover magnet; first and second stator magnets; a cylindrical holder having through holes that are open at both ends and having flanges on at least both ends of its outer surface; a drive winding that is arranged on the outer surface of the cylindrical holder and wound in at least two recesses formed between the flanges provided on both ends; and a case that houses the cylindrical holder and the drive winding; wherein the mover magnet is housed in the through holes in a state in which it can vibrate in a first direction parallel to the axis of the through holes, and the first and second stator magnets are arranged to sandwich the mover magnet between them in the first direction, and their magnetic poles are arranged to repel the mover magnet; and the cylindrical holder has a first opening in one of the flanges at both ends that communicates with the through holes and has a diameter larger than that of the through holes, a second opening in communication with the through hole and having a diameter larger than that of the through hole at the other end of the flanges; the first stator magnet is fitted into the first opening and fixed to the cylindrical holder; the second stator magnet is fitted into the second opening and fixed to the cylindrical holder; and the center of the first stator magnet fitted into the first opening and the center of the second stator magnet fitted into the second opening are offset in the same direction relative to the center of the through hole.

2. A vibration motor comprising: a mover magnet; first and second stator magnets; a cylindrical holder having a through hole that is open at both ends and has a plurality of flanges on its outer surface; a drive winding that is disposed on the outer circumferential surface of the cylindrical holder and wound in a recess formed between the plurality of flanges; and a case that accommodates the cylindrical holder and the drive winding; wherein the mover magnet is accommodated in the through hole in a state in which it can vibrate in a first direction parallel to the axis of the through hole; the first stator magnet and the second stator magnet are arranged to sandwich the mover magnet between them in the first direction, and their magnetic poles are arranged to repel the mover magnet; and the case has a first recess formed at a position facing one end of the cylindrical holder and a second recess formed at a position facing the other end of the cylindrical holder; the first stator magnet is fitted into the first recess and fixed to the case; the second stator magnet is fitted into the second recess and fixed to the case, and the center of the first stator magnet fitted into the first recess and the center of the second stator magnet fitted into the second recess are offset in the same direction relative to the center of the through hole.

3. The vibration motor according to claim 1, wherein the first stator magnet and the second stator magnet are fixed to the cylindrical holder with an adhesive.

4. The vibration motor according to claim 2, wherein the first stator magnet and the second stator magnet are fixed to the case with an adhesive.

5. A vibration motor according to any one of claims 1 to 4, wherein the mover magnet is made of a plurality of permanent magnets attached together in directions in which they attract each other.

6. The vibration motor according to claim 5, wherein the mover magnet is formed by sandwiching a metal having a specific gravity greater than that of the permanent magnets between the plurality of permanent magnets.

7. A vibration motor according to any one of claims 1 to 6, wherein the center of the first stator magnet and the center of the second stator magnet are coaxial in the first direction.

8. A vibration motor as described in any one of claims 1 to 7, wherein, regardless of the position of the mover magnet in the first direction, the component of the resultant force of the first repulsive force exerted on the mover magnet by the first stator magnet and the second repulsive force exerted on the mover magnet by the second stator magnet, which is perpendicular to the inner wall surface of the through hole, is greater than the gravity of the mover magnet.

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