Vibration motor

Abstract

A vibration motor (10) comprises a mover magnet (60), a stator magnet (51) and a stator magnet (52), a cylindrical holder (30), drive windings (41, 42), and a case (20). The cylindrical holder (30) has a through-hole (300) comprising a first end and a second end, both ends of the through-hole (300) being open. The drive windings (41, 42) are wound around the outer circumferential surface of the cylindrical holder (30). The case (20) accommodates the stator magnet (51), the stator magnet (52), the cylindrical holder (30), and the drive windings (41, 42). The mover magnet (60) is accommodated in the through-hole (300) in a state of being capable of vibrating in a first direction parallel to the axis of the through-hole (300). The stator magnet (51) and the stator magnet (52) are disposed so as to sandwich the mover magnet (60) therebetween in the first direction and are arranged such that the magnetic poles thereof repel the mover magnet (60). The case (20) has a recess (211) at a position facing the first end of the cylindrical holder (30) and has a recess (221) at a position facing the second end. The stator magnet (51) is accommodated in the recess (211), and the stator magnet (52) is accommodated in the recess (221). In the first direction, a buffer body (71) that can contact the mover magnet (60) is provided between the mover magnet (60) and the stator magnet (51), and a buffer body (72) that can contact the mover magnet (60) is provided between the mover magnet (60) and the stator magnet (52).

Description

Vibration motor

[0001] The present invention relates to a vibration motor having a configuration in which a movable magnet is housed in a cylindrical holder so as to be vibrable.

[0002] Patent Document 1 describes a vibration actuator. The vibration actuator in Patent Document 1 comprises a disc-shaped magnet and a movable body connected to the magnet and using a spring.

[0003] The vibration actuator described in Patent Document 1 generates vibration acceleration by causing a movable body to collide with a housing or the like.

[0004] Japanese Patent Publication No. 2022-179794

[0005] However, in configurations that use a movable body with a leaf spring, such as the vibration actuator described in Patent Document 1, durability cannot be said to be high due to the possibility of the movable body being damaged by collisions, etc.

[0006] Therefore, the object of the present invention is to provide a vibration motor that can achieve high acceleration and has high durability.

[0007] A vibration motor according to one embodiment of the present invention includes a mover magnet, first and second stator magnets, a cylindrical holder, a drive winding, and a case. The cylindrical holder has a through hole with both ends open, each defined by a first end and a second end. The drive winding is wound around the outer circumferential surface of the cylindrical holder. The case accommodates the first and second stator magnets, the cylindrical holder, and the drive winding. 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 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.

[0008] The case has a first recess at a position opposite the first end of the cylindrical holder and a second recess at a position opposite the second end. The first stator magnet is housed in the first recess, and the second stator magnet is housed in the second recess.

[0009] In the first direction, a first buffer that can contact the movable magnet is provided between the movable magnet and the first stator magnet, and a second buffer that can contact the movable magnet is provided between the movable magnet and the second stator magnet.

[0010] In this configuration, the mover magnet can be brought into contact (collided) with the first buffer body and the second tube inner portion while using the magnetic spring method.

[0011] According to the present invention, a vibration motor that can achieve high acceleration and high durability can be realized.

[0012] Figure 1 is a cross-sectional view showing an example of the configuration of a vibration motor according to the first embodiment. Figure 2 is an exploded perspective view showing an example of the configuration of a vibration motor according to the first embodiment. Figures 3(A) and 3(B) are cross-sectional views showing the state in which the movable magnet collides with the buffer in the first embodiment. Figure 4 is a graph showing an example of the simulation results of electromagnetic force and gravity with respect to the position of the movable magnet. Figures 5(A), 5(B), and 5(C) are perspective views showing the configuration in the manufacturing process of the vibration motor. Figure 6 is a cross-sectional view showing an example of the configuration of a vibration motor according to the second embodiment. Figures 7(A) and 7(B) are cross-sectional views showing the state in which the movable magnet collides with the buffer in the second embodiment. Figure 8 is a cross-sectional view showing an example of the configuration of a vibration motor according to the third embodiment. Figure 9 is a cross-sectional view showing an example of the configuration of a vibration motor according to the fourth embodiment.

[0013] First Embodiment A vibration motor according to a first embodiment of the present invention will be described with reference to the drawings.

[0014] Figure 1 is a cross-sectional view showing an example of the configuration of a vibration motor according to the first embodiment. Figure 2 is an exploded perspective view showing an example of the configuration of a vibration motor according to the first embodiment.

[0015] As shown in Figures 1 and 2, the vibration motor 10 comprises 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 movable 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 and the second housing 22 are formed from insulating resin. 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. A recess 211 recessed from the bottom surface BF21 is formed in the bottom surface BF21.

[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. A recess 221 recessed from the bottom surface BF22 is formed in the bottom surface BF22.

[0019] The diameter of the recess 211 and the diameter of the recess 221 are the same and are smaller than the diameter of the through-hole 300 of the cylindrical holder 30 .

[0020] 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.

[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 the first direction. The through hole 300 has a constant diameter from the first end to the second end. The main body 31 is provided with an inner wall surface FI 31 through this through hole 300.

[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. 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. The opening OP322 corresponds to the second opening.

[0028] The openings OP321 and OP322 have the same diameter. The central axes of the openings OP321 and OP322 substantially coincide with the central axis of the through-hole 300.

[0029] 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.

[0030] 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.

[0031] The stator magnet 51, stator magnet 52, and movable magnet 60 are composed of ferromagnetic permanent magnets. For example, the stator magnet 51, stator magnet 52, and movable magnet 60 are composed of neodymium magnets.

[0032] The stator magnet 51, stator magnet 52, and movable magnet 60 are cylindrical in shape. The diameters of the stator magnet 51 and stator magnet 52 are smaller than the diameter of the movable magnet 60.

[0033] The diameter of the stator magnet 51 is approximately the same as the diameter of the recess 211, and is less than or equal to the diameter of the recess 211. In this case, the difference between the radius of the stator magnet 51 and the radius of the recess 211 is within the range of manufacturing tolerance. The stator magnet 51 is fitted into the recess 211 and bonded to the first housing 21 with adhesive.

[0034] The diameter of the stator magnet 52 is approximately the same as the diameter of the recess 221, and is less than or equal to the diameter of the recess 221. In this case, the difference between the radius of the stator magnet 52 and the radius of the recess 221 is within the range of manufacturing tolerance. The stator magnet 52 is fitted into the recess 221 and bonded to the second housing 22 with adhesive.

[0035] The diameter of the movable magnet 60 is approximately the same as the diameter of the through hole 300, and is less than or equal to the diameter of the through hole 300. The movable magnet 60 is housed in the through hole 300 of the cylindrical holder 30 in a state that allows it to vibrate (slide) in the first direction.

[0036] In this configuration, the stator magnet 51 and the movable magnet 60 are positioned so that their magnetic poles face each other. Furthermore, the stator magnet 52 and the movable magnet 60 are positioned so that their magnetic poles face each other.

[0037] As a specific example, in the case shown in Figure 1, the movable magnet 60 is positioned so that its north pole surface 60N faces the stator magnet 51 side (the first end side of the cylindrical holder 30). The movable magnet 60 is positioned so that its south pole surface 60S faces the stator magnet 52 side (the second end side of the cylindrical holder 30).

[0038] The stator magnet 51 is positioned so that its north pole surface 51N faces the movable magnet 60. The south pole surface 51S of the stator magnet 51 is positioned so that it faces outward along the first direction from the first end of the main body 31. As a result, the stator magnet 51 is positioned to generate a magnetic repulsive force against the movable magnet 60.

[0039] The stator magnet 52 is positioned so that its south pole surface 52S faces the movable magnet 60. The north pole surface 52N of the stator magnet 52 is positioned so that it faces outward along the first direction from the second end of the main body 31. As a result, the stator magnet 52 is positioned to generate a magnetic repulsive force against the movable magnet 60.

[0040] The buffer body 71 and the buffer body 72 are made of, for example, urethane rubber. The buffer body 71 and the buffer body 72 are cylindrical. The buffer body 71 corresponds to the first buffer body, and the buffer body 72 corresponds to the second buffer body.

[0041] The diameter of the buffer 71 is larger than the diameter of the through hole 300. The diameter of the buffer 71 is approximately the same as the diameter of the opening OP321, and is less than or equal to the diameter of the opening OP321. In this case, the difference between the radius of the buffer 71 and the radius of the opening OP321 is within the range of manufacturing tolerance. The buffer 71 is fitted into the opening OP321 and bonded to the cylindrical holder 30 with adhesive.

[0042] The diameter of the buffer 72 is larger than the diameter of the through hole 300. The diameter of the buffer 72 is approximately the same as the diameter of the opening OP322, and is less than or equal to the diameter of the opening OP322. In this case, the difference between the radius of the buffer 72 and the radius of the opening OP322 is within the range of manufacturing tolerance. The buffer 72 is fitted into the opening OP322 and bonded to the cylindrical holder 30 with adhesive.

[0043] The drive winding 41, drive winding 42, stator magnet 51, stator magnet 52, movable magnet 60, buffer 71, and the cylindrical holder 30 to which the buffer 71 is mounted are housed in the internal space of the case 20, which consists of the internal space 210 of the first housing 21 and the internal space 220 of the second housing 22. At this time, the first end of the cylindrical holder 30 in the first direction and the buffer 71 abut against the bottom surface BF21 of the first housing 21. The second end of the cylindrical holder 30 in the first direction and the buffer 72 abut against the bottom surface BF22 of the second housing 22. The terminal conductors OL 41 and OL 42 are drawn out to the outside of the case 20 through the gap on the side where the first housing 21 and the second housing 22 are in contact.

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

[0045] In this process, the movable magnet 60 receives a repulsive magnetic force from the stator magnets 51 and 52 at both ends in the first direction. As a result, the movable magnet 60 vibrates along the first direction. Therefore, the vibration motor 10 can generate vibrations using a magnetic spring mechanism.

[0046] This vibration is transmitted to the case 20, allowing the vibration motor 10 to impart vibration to objects or people that come into contact with the case 20.

[0047] Furthermore, the magnetic force strength of the stator magnet 51, stator magnet 52, and movable magnet 60, and the magnitude of the current flowing through the drive winding 41 and drive winding 42 are adjusted as appropriate. As a result, as shown in Figures 3(A) and 3(B), the movable magnet 60 collides with (comes into) the buffer 71 or buffer 72.

[0048] Figures 3(A) and 3(B) are cross-sectional views showing the state in which the movable magnet collides with the buffer in the first embodiment. Figure 3(A) shows the state in which the movable magnet 60 collides with the buffer 71, and Figure 3(B) shows the state in which the movable magnet 60 collides with the buffer 72.

[0049] As shown in Figures 3(A) and 3(B), the collision of the mover magnet 60 with the buffer 71 or 72 can increase the acceleration of the mover magnet 60. This allows the vibration motor 10 to supply vibrations of greater amplitude to the case 20. Therefore, the vibration motor 10 can effectively apply greater vibrations to objects or people that come into contact with the case 20. As a result, the vibration motor 10 can achieve greater acceleration. Furthermore, because the vibration motor 10 does not have a leaf spring structure, it can achieve high durability. In particular, by using the buffers 71 and 72, damage to the mover magnet 60 can be appropriately suppressed when the mover magnet 60 collides.

[0050] Furthermore, in this configuration, a buffer 71 is disposed between the mover magnet 60 and the stator magnet 51, and a buffer 72 is disposed between the mover magnet 60 and the stator magnet 52. Therefore, the mover magnet 60 does not collide with the stator magnets 51 and 52. This allows the vibration motor 10 to prevent damage to the mover magnet 60 and the stator magnets 51 and 52.

[0051] The buffers 71 and 72 are not limited to urethane rubber. The buffers 71 and 72 may have a lower modulus of elasticity than the stator magnets 51 and 52. More preferably, the buffers 71 and 72 have a lower modulus of elasticity than the first housing 21 and the second housing 22. However, if the modulus of elasticity of the buffers 71 and 72 is made too low, the effect of improving acceleration will be suppressed. Therefore, the modulus of elasticity of the buffers 71 and 72 may be appropriately set based on the magnitude of vibration and durability required for the vibration motor 10.

[0052] Furthermore, the vibration motor 10 can also achieve the following effects.

[0053] When viewed in the first direction, the center of recess 211 and the center of recess 221 are offset from the center of through hole 300. More specifically, the center of recess 211 and the center of recess 211 are coaxial in the first direction. The center of recess 211 and the central axis of the opening that passes through the center of recess 211 are at a position different from central axis AX30 of through hole 300.

[0054] As a result, the centers of the stator magnet 51 and the stator magnet 52 are offset from the center of the movable magnet 60. More specifically, the center of the movable magnet 60 lies on the central axis AX 30 of the through hole 300. The central axis AX 50 connecting the centers of the stator magnet 51 and the stator magnet 52 coincides with the central axis of the opening.

[0055] Therefore, the central axis through which the center of the movable magnet 60 passes when it vibrates is different from the central axis AX50 that connects the centers of the stator magnets 51 and 52. Furthermore, the central axis AX50 connecting the centers of the stator magnets 51 and 52 is shifted to the same side relative to the central axis AX30 on which the movable magnet 60 vibrates, regardless of the position of the movable magnet 60 in the first direction.

[0056] In this configuration, the magnetic forces of the stator magnets 51 and 52 apply a force to the mover magnet 60 in a direction perpendicular to the vibration direction (first direction), regardless of the position of the mover magnet 60 .

[0057] This force 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.

[0058] This suppresses rattling of the movable magnet 60 during vibration.

[0059] Figure 4 is a graph showing an example of simulation results for electromagnetic force and gravity with respect to the position of the movable magnet.

[0060] In this way, in the vibration motor 10, regardless of the position of the mover magnet 60, the force (electromagnetic force) pressing the mover magnet 60 against the inner wall surface FI31 exceeds the gravity acting on the mover magnet 60. Therefore, the vibration motor 10 can achieve quieter operation.

[0061] Furthermore, the central axes AX30 and AX50 are not necessarily offset from each other; they may coincide.

[0062] The buffer 71 may be sandwiched between the cylindrical holder 30 and the first housing 21A and fixed without using adhesive. Similarly, the buffer 72 may be sandwiched between the cylindrical holder 30 and the second housing 22A and fixed without using adhesive.

[0063] However, as described above, the buffer 71 is fixed to the opening OP321 with adhesive, and the buffer 72 is fixed to the opening OP322 with adhesive. In this way, both ends of the through hole 300 are sealed by the buffer 71 and the buffer 72.

[0064] Therefore, even if oil is placed in the through-hole 300 to improve the sliding properties of the movable magnet 60, the vibration motor 10 can prevent oil leakage. In particular, if the diameter of the buffer 71 is the same as the diameter of the opening OP321 and the diameter of the buffer 72 is the same as the opening OP322, oil leakage can be prevented more reliably.

[0065] Furthermore, by sealing oil in the through-hole 300, the acceleration of the movable magnet 60 is improved. Therefore, the vibration motor 10 can achieve even greater acceleration and higher durability.

[0066] The vibration motor 10 with the above configuration is manufactured, for example, as follows. Figures 5(A), 5(B), and 5(C) are perspective views showing the configuration during the manufacturing process of the vibration motor.

[0067] First, as shown in Figure 5(A), the drive windings 41 and 42 are mounted on the cylindrical holder 30.

[0068] Next, as shown in Figure 5(B), the movable magnet 60 is inserted into the through hole 300 of the cylindrical holder 30.

[0069] Next, as shown in Figure 5(C), the buffer 71 is attached to the opening OP321 and then bonded and fixed to the cylindrical holder 30 with adhesive. Similarly, the buffer 72 is attached to the opening OP322 and then bonded and fixed to the cylindrical holder 30 with adhesive.

[0070] Next, the stator magnet 51 is attached to the recess 221 of the first housing 21, and the stator magnet 51 is bonded and fixed to the first housing 21 with adhesive. Similarly, the stator magnet 52 is attached to the recess 221 of the second housing 22, and the stator magnet 52 is bonded and fixed to the second housing 22 with adhesive.

[0071] A cylindrical holder 30, on which drive windings 41, drive windings 42, movable magnet 60, buffer 71, and buffer 72 are mounted, is covered by a case 20 consisting of a first housing 21 on which stator magnet 51 is mounted and a second housing 22 on which stator magnet 52 is mounted.

[0072] The vibration motor 10 can be manufactured with this configuration.

[0073] [Second Embodiment] A vibration motor according to a second embodiment of the present invention will be described with reference to the figures. Figure 6 is a cross-sectional view showing an example of the configuration of the vibration motor according to the second embodiment.

[0074] 6, the vibration motor 10A according to the second embodiment differs from the vibration motor 10 according to the first embodiment in the shapes of the case 20A and the cylindrical holder 30A, and in that the vibration motor 10A does not include the buffers 71 and 72. The other configurations of the vibration motor 10A are the same as those of the vibration motor 10, and a description of the same parts will be omitted.

[0075] The first housing 21A of the case 20A has a recess 211A. The depth of the recess 211A is greater than the height of the stator magnet 51. The stator magnet 51 is housed in and adhered to the recess 211A so as to contact the bottom surface of the recess 211A. This prevents the stator magnet 51 from reaching the bottom surface BF21 of the first housing 21A. In other words, in the first direction, the stator magnet 51 is positioned closer to the outer end surface of the first housing 21A (the surface at the right end of the first housing 21A in FIG. 5 ) than the bottom surface BF21.

[0076] The second housing 22A of the case 20A has a recess 221A. The depth of the recess 221A is greater than the height of the stator magnet 52. The stator magnet 52 is housed in the recess 221A and adhered so as to contact the bottom surface of the recess 221A. This prevents the stator magnet 52 from reaching the bottom surface BF22 of the second housing 22A. In other words, in the first direction, the stator magnet 52 is positioned closer to the outer end surface of the second housing 22A (the left-end surface of the second housing 22A in FIG. 5 ) than the bottom surface BF22.

[0077] The cylindrical holder 30A does not have openings at the first end and the second end.

[0078] The vibration motor 10A does not include separate shock absorbers 71 and 72 relative to the case 20A and the cylindrical holder 30A.

[0079] Figures 7(A) and 7(B) are cross-sectional views showing the state in which the movable magnet collides with the buffer in the second embodiment. Figure 7(A) shows the state in which the movable magnet 60 collides with the bottom surface BF21 of the first housing 21A. Figure 7(B) shows the state in which the movable magnet 60 collides with the bottom surface BF22 of the second housing 22A.

[0080] As shown in Figures 7(A) and 7(B), in the vibration motor 10A, when the movable magnet 60 vibrates, it collides with the bottom surface BF21 of the first housing 21A or the bottom surface BF22 of the second housing 22A. That is, the wall forming the bottom surface BF21 of the first housing 21A functions as the first buffer of the present invention. The wall forming the bottom surface BF22 of the second housing 22A functions as the second buffer of the present invention.

[0081] As a result, the vibration motor 10A can achieve high acceleration and high durability. In particular, if the first housing 21A and the second housing 22A are made of insulating resin, damage to the mover magnet 60 can be reduced compared to when they are made of metal.

[0082] Furthermore, with this configuration, the mover magnet 60 does not collide with the stator magnets 51 and 52. As a result, the vibration motor 10A can prevent damage to the mover magnet 60 and the stator magnets 51 and 52.

[0083] Furthermore, since the vibration motor 10A does not require a separate damping element from the case 20A, the configuration can be simplified.

[0084] [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.

[0085] 8, the vibration motor 10B according to the third embodiment differs from the vibration motor 10A according to the second embodiment in that it includes a buffer 71B and a buffer 72B. The other configuration of the vibration motor 10B is the same as that of the vibration motor 10A, and a description of the same parts will be omitted.

[0086] The vibration motor 10B includes a case 20B, a cylindrical holder 30B, a buffer body 71B, and a buffer body 72B.

[0087] The first housing 21B of the case 20B has the same configuration as the first housing 21A of the case 20A. The second housing 22B of the case 20B has the same configuration as the second housing 22A of the case 20A.

[0088] The cylindrical holder 30B does not have openings at the first end and the second end, similar to the cylindrical holder 30A, In other words, the cylindrical holder 30B has only a through-hole 300 with a fixed diameter.

[0089] The buffer body 71B and the buffer body 72B are cylindrical. The diameters of the buffer body 71B and the buffer body 72B are substantially the same as the diameter of the through-hole 300.

[0090] Cushioning body 71B is disposed at a first end position of through-hole 300. Cushioning body 72B is disposed at a second end position of through-hole 300. Cushioning body 71B and cushioning body 72B are each adhered to inner wall surface FI31 of cylindrical holder 30B with an adhesive.

[0091] With this configuration, the vibration motor 10B can achieve high acceleration and high durability, similar to the vibration motors 10 and 10A. Furthermore, the vibration motor 10B can simplify the shape of the cylindrical holder 30B.

[0092] [Fourth embodiment] A vibration motor according to a fourth embodiment of the present invention will be described with reference to the drawings. Fig. 9 is a cross-sectional view showing an example of the configuration of a vibration motor according to the fourth embodiment.

[0093] 9, the vibration motor 10C according to the fourth embodiment differs from the vibration motor 10 according to the first embodiment in the shapes of the case 20C and the cylindrical holder 30C, and in that the case 20C houses the buffers 71 and 72. The other configuration of the vibration motor 10C is the same as that of the vibration motor 10, and a description of similar parts will be omitted.

[0094] The case 20C includes a first housing 21C and a second housing 22C.

[0095] The first housing 21C has a recess 211C. The recess 211C has a two-stage structure and is composed of an open side portion and a closed side portion, each of which is cylindrical. The open side portion has a larger diameter than the closed side portion.

[0096] The diameter of the open side portion of the first housing 21C is approximately the same as the diameter of the buffer 71. The diameter of the closed side portion of the first housing 21C is approximately the same as the diameter of the stator magnet 51. The stator magnet 51 is housed in the closed side portion of the first housing 21C. The buffer 71 is housed in the open side portion of the first housing 21C. The stator magnet 51 and the buffer 71 are bonded and fixed to the first housing 21C with adhesive.

[0097] The second housing 22C has a recess 221C. The recess 221C has a two-stage structure and is composed of an open side portion and a closed side portion, each of which is cylindrical. The open side portion has a larger diameter than the closed side portion.

[0098] The diameter of the open side portion of the second housing 22C is approximately the same as the diameter of the buffer 72. The diameter of the closed side portion of the second housing 22C is approximately the same as the diameter of the stator magnet 52. The stator magnet 52 is housed in the closed side portion of the second housing 22C. The buffer 72 is housed in the open side portion of the second housing 22C. The stator magnet 52 and the buffer 72 are bonded and fixed to the second housing 22C with adhesive.

[0099] The cylindrical holder 30C does not have openings at its first and second ends. The first end face of the cylindrical holder 30C abuts against the bottom surface BF21 of the first housing 21A and a part (outer edge) of the buffer 71. The second end face of the cylindrical holder 30C abuts against the bottom surface BF22 of the second housing 22A and a part (outer edge) of the buffer 72.

[0100] With this configuration, the vibration motor 10C can achieve high acceleration and high durability, similar to the vibration motors 10, 10A, and 10B. Furthermore, the vibration motor 10C can simplify the shape of the cylindrical holder 30C.

[0101] <1> A vibration motor comprising: a movable magnet; a first stator magnet and a second stator magnet; a cylindrical holder having a through hole with both ends open, formed by a first end and a second end; a drive winding wound around the outer circumferential surface of the cylindrical holder; and a case housing the first stator magnet, the second stator magnet, the cylindrical holder, and the drive winding, wherein the movable magnet is housed in the through hole in a state that 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 in the first direction so as to sandwich the movable magnet between them, and their magnetic poles are arranged to repel the movable magnet, wherein the case has a first recess at a position opposite to the first end of the cylindrical holder; and a second recess at a position opposite to the second end of the cylindrical holder; the first stator magnet is housed in the first recess; and the second stator magnet is housed in the second recess. a vibration motor having a first buffer body between the mover magnet and the first stator magnet in the first direction, the first buffer body being capable of contacting the mover magnet, and a second buffer body between the mover magnet and the second stator magnet, the second buffer body being capable of contacting the mover magnet.

[0102] <2> The vibration motor according to <1>, wherein, when viewed in the first direction, the first stator magnet and the second stator magnet are smaller than the movable magnet.

[0103] <3> The vibration motor according to <2>, wherein the thickness of the first stator magnet is less than the depth of the first recess, the first buffer is a wall portion that forms the opening of the first recess, and the thickness of the second stator magnet is less than the depth of the second recess, the second buffer is a wall portion that forms the opening of the second recess.

[0104] <4> The vibration motor according to <1> or <2>, wherein the first buffer is disposed at the first end of the cylindrical holder, the second buffer is disposed at the second end of the cylindrical holder, and the elastic modulus of the first buffer and the second buffer is lower than the elastic modulus of the case.

[0105] <5> The vibration motor according to <4>, wherein the cylindrical holder is provided with flanges at the first and second ends, the flange at the first end communicates with the through hole and has a first opening larger in diameter than the through hole, the flange at the second end communicates with the through hole and has a second opening larger in diameter than the through hole, the first buffer is housed in the first opening, and the second buffer is housed in the second opening.

[0106] <6> The vibration motor according to any one of <1>, <2>, <4>, or <5>, wherein the first recess and the second recess have a two-stage structure consisting of an open side portion and a closed side portion, the open side portion having a larger diameter than the closed side portion, the first stator magnet is housed in the closed side portion of the first recess and the first buffer is housed in the open side portion, and the second stator magnet is housed in the closed side portion of the second recess and the second buffer is housed in the open side portion.

[0107] <7> The vibration motor according to any one of <4> to <6>, wherein the first and second shock absorbers are made of urethane rubber.

[0108] 10, 10A, 10B, 10C: Vibration motor 20, 20A, 20B, 20C: Case 21, 21A, 21B, 21C: First housing 22, 22A, 22B, 22C: Second housing 30, 30A, 30B, 30C: Cylindrical holder 31: Main body 41, 42: Drive winding 51, 52: Stator magnet 51N, 52N, 60N: N pole surface 51S, 52S, 60S: S pole surface 60: Movable magnet 71, 71B, 72, 72B: Cushion 210, 220: Internal space 211, 211A, 211C, 221, 221A, 221C: Recess 300: Through hole 310, 321, 322: Flange AX30, AX50: Central axis BF21, BF22: Bottom surface FI31: Inner wall surface OL41, OL42: Terminal conductor OP321, OP322: Opening

Claims

1. A vibration motor comprising: a mover magnet; a first stator magnet and a second stator magnet; a cylindrical holder having a through hole with both ends open and defined by a first end and a second end; a drive winding wound around the outer circumferential surface of the cylindrical holder; and a case that accommodates the first stator magnet, the second stator magnet, 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 in the first direction, and their magnetic poles are arranged to repel the mover magnet; and the case has a first recess at a position facing the first end of the cylindrical holder and a second recess at a position facing the second end of the cylindrical holder; the first stator magnet is accommodated in the first recess, and the second stator magnet is accommodated in the second recess. a first buffer body between the mover magnet and the first stator magnet, the first buffer body being capable of contacting the mover magnet in the first direction, and a second buffer body between the mover magnet and the second stator magnet, the second buffer body being capable of contacting the mover magnet.

2. The vibration motor according to claim 1, wherein the first stator magnet and the second stator magnet are smaller than the mover magnet when viewed in the first direction.

3. The vibration motor according to claim 2, wherein the thickness of the first stator magnet is smaller than the depth of the first recess, the first buffer body is a wall portion that forms the opening of the first recess, and the thickness of the second stator magnet is smaller than the depth of the second recess, and the second buffer body is a wall portion that forms the opening of the second recess.

4. A vibration motor as described in claim 1 or claim 2, wherein the first buffer is disposed at the first end of the cylindrical holder, the second buffer is disposed at the second end of the cylindrical holder, and the elastic modulus of the first buffer and the second buffer is lower than the elastic modulus of the case.

5. A vibration motor as described in claim 4, wherein the cylindrical holder has flanges at the first end and the second end, the flange at the first end having a first opening communicating with the through hole and having a larger diameter than the through hole, the flange at the second end having a second opening communicating with the through hole and having a larger diameter than the through hole, the first buffer body being housed in the first opening, and the second buffer body being housed in the second opening.

6. A vibration motor as described in any one of claims 1, 2, 4 and 5, wherein the first recess and the second recess have a two-stage structure consisting of an open side portion and a closed side portion, the open side portion having a larger diameter than the closed side portion, the first recess houses the first stator magnet in the closed side portion and the first buffer body in the open side portion, and the second recess houses the second stator magnet in the closed side portion and the second buffer body in the open side portion.

7. The vibration motor according to any one of claims 4 to 6, wherein the first buffer body and the second buffer body are made of urethane rubber.

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