vibration actuator

Abstract

Provided is a weight that is easy to manufacture, has optimal weight and high strength, and a vibration actuator that has excellent vibration characteristics. The invention includes a cylindrical housing (2), a coil (21) provided to the housing (2), and a movable member (4) that vibrates along a vibration axis (O) of the housing (2). The movable member (4) includes a movable member body and a weight (32) fixed to the movable member body. A protruding portion (311) that protrudes toward an opening of the housing (2) is provided to a central portion of the movable member body, and a recessed portion (321) that is recessed toward the opening of the housing (2) is provided to a central portion of the weight (32). The movable member body and the weight (32) are fixed in a state in which the protruding portion (311) is inserted into the recessed portion (321).

Description

Technical Field

[0001] This invention relates to a vibration actuator, and more particularly to a small and lightweight vibration actuator used in mobile terminals such as mobile phones or smartphones, game console controllers, etc. Background Technology

[0002] In the past, mobile phones and other communication devices have used vibration actuators (or vibration motors) to notify people of incoming calls or alarms. Furthermore, in recent years, vibration actuators have also been used in the fields of film, games, and virtual reality (VR), for example, as performance effects in action scenes or as a means of feedback to players, stimulating the sense of touch through vibration to enhance realism.

[0003] Vibration actuators also include those that use a motor to rotate an eccentric weight, thereby generating vibration through inertial force. However, the method of using a rotary motor to generate vibration through the inertial force of the eccentric weight has the disadvantage of being slow to respond from the start of the eccentric weight's rotation until the vibration is felt in the form of touch, which detracts from the realism of the vibration.

[0004] Therefore, as an actuator for obtaining a more realistic tactile sensation, a voice coil actuator is sometimes employed, as shown in Patent Document 1, for example. In this vibration actuator, a movable element with a magnet is disposed within a cylindrical housing, and a coil fixed to the housing is disposed around the movable element. By energizing the coil, the movable element is caused to reciprocate within the housing.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2016-28819 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] In Patent Document 1, a through hole is provided in the pole piece to fix the weight, which is a movable structural member, into the pole piece, and a protrusion of the weight is inserted into the through hole. However, since the pole piece becomes a channel (magnetic circuit) for the magnetic flux generated by the magnet, the through hole shields the magnetic flux, which is undesirable. In particular, since the through hole is located in the center of the pole piece, the magnetic flux from the center of the magnet leaks through the through hole into the atmosphere (outside the pole piece), making it impossible to effectively utilize the magnetic force of the magnet.

[0010] Furthermore, considering the weight and balance characteristics of the weights, a complex cross-sectional shape with a high height along the vibration axis is used instead of a simple plate shape. Such weights cannot be manufactured by stamping like simple plate weights. Therefore, they can be manufactured using molding methods such as forming the weight as a whole using resin molding, embedding metal within resin, die casting (where molten metal flows into a mold and solidifies), hot isostatic pressing (where metal powder is supplied to a mold and solidified), and metal injection molding. When manufacturing weights using these methods, if the weight has fine protrusions, the space in the mold for these protrusions is narrower than other parts, making it difficult for resin or metal material to flow into or fill such narrow areas.

[0011] Furthermore, magnets or Hall elements generate magnetic flux, forming a magnetic circuit, thus requiring a metallic construction. On the other hand, regarding the weights, it has been proposed to manufacture them entirely or partially using resin. That is, when the vibrating actuator is stationary, the movable part supported by the leaf spring may tilt within the housing due to external vibrations or impacts, potentially contacting the inner surface of the housing or the coil. Therefore, it has been proposed that by increasing the height of the weight in the vibration axis direction, or by making its outer diameter larger than that of the magnet, and by using a resin weight, or at least a weight with its surface coated with resin, even if the weight contacts the inner surface of the housing, neither the weight nor the inner surface of the housing will be damaged.

[0012] Furthermore, as mentioned above, to prevent damage to moving parts or the housing, and to facilitate easy adjustment of the weight, the weight's shape must be complex, such as a bowl shape. In cases where the weight is entirely molded from resin, or where metal is embedded within the resin using methods such as inlay molding, the protrusions on such weights are mostly made of resin. In such weights, the resin protrusions may break when force is applied.

[0013] This invention addresses the problems of the prior art. The objective of this invention is to provide a vibration actuator that utilizes a weight that is easily manufactured to achieve optimal weight and high strength, and exhibits excellent vibration characteristics.

[0014] Technical means to solve the problem

[0015] The vibration actuator of the present invention has the following structure.

[0016] (1) A cylindrical shell.

[0017] (2) A coil disposed in the housing.

[0018] (3) A movable part that vibrates along the vibration axis of the housing.

[0019] (4) The movable part includes a movable part body and a weight fixed to the movable part body.

[0020] (5) A protrusion is provided at the center of the movable part body, which protrudes toward the opening of the housing.

[0021] (6) A recessed portion is provided at the center of the weight, which is recessed toward the opening of the housing.

[0022] (7) When the protrusion is inserted into the recess, the movable body and the weight are fixed.

[0023] The following structure can be adopted in this invention.

[0024] (1) The movable part body includes a pole piece and a magnet.

[0025] (2) The diameter of the concave portion of the weight is greater than the diameter of the central axis of the weight.

[0026] (3) The electrode is fixed to the opening side of the housing in the magnet, and the protrusion is disposed at the center of the electrode.

[0027] (4) The weight has a bottomed cylindrical portion, the bottom of which extends in a direction orthogonal to the vibration axis, and the cylindrical portion of which opens toward the opening of the housing.

[0028] (5) The weight has a cylindrical part integrally formed with the bottomed cylindrical part at its center, and the cylindrical part extends along the vibration axis towards the opening of the shell.

[0029] (6) The outer periphery of the bottomed cylindrical portion is located on the outermost periphery side of the movable member.

[0030] (7) The weight has ribs between the cylindrical portion and the tube portion, starting from the root portion of the cylindrical portion.

[0031] (8) The central part of the rib is thicker than the outer periphery of the rib.

[0032] (9) The face of the rib on the opening side of the shell is formed by at least two planes at different angles.

[0033] The effects of the invention

[0034] This invention provides a vibration actuator that is easy to manufacture with optimal weight and high strength, and has excellent vibration characteristics. Attached Figure Description

[0035] Figure 1 This is an exploded perspective view showing the overall structure of the first embodiment.

[0036] Figure 2 This is a cross-sectional view showing the overall structure of the first embodiment cut along the vibration axis.

[0037] Figure 3 This is an exploded perspective view of the weights, pole pieces, and magnet in the first embodiment.

[0038] Figure 4 This is an exploded perspective view of the housing body, weights, leaf springs, and vibration damping components in the first embodiment.

[0039] Figure 5 This is a perspective view of the state after the housing body, weights, leaf springs and vibration damping components are combined in the first embodiment.

[0040] Figures 6(a) and 6(b) are plan views showing the positional relationship between the corners of the triangular shaft hole and the central shaft and the through hole or rib in the first embodiment.

[0041] Figure 7 This is an enlarged view showing the shape of the weights in the first embodiment.

[0042] Figure 8 This is a diagram illustrating the operation of the first embodiment.

[0043] [Explanation of Symbols]

[0044] 1: Vibration actuator

[0045] 2: Shell

[0046] 3: Electromagnetic drive unit on the housing side

[0047] 4: Movable parts

[0048] 5: Leaf Spring

[0049] 11: Cover

[0050] 12: Inner guide rod

[0051] 13: Terminal

[0052] 14: Flange portion

[0053] 15: Protrusion

[0054] 20: Magnetic yoke

[0055] 21: Coil

[0056] 30: Magnet

[0057] 31: Extreme film

[0058] 311: Protrusion

[0059] 312: concave part

[0060] 32: Weights

[0061] 321: concave part

[0062] 322: Cylindrical part

[0063] 323: Bottom

[0064] 324: Central axis

[0065] 325: Tube section

[0066] 326: Ribs

[0067] 326a: Inclined surface

[0068] 326b: Plane

[0069] 41: Vibration damping components

[0070] 50: Shaft hole

[0071] 51: Support section

[0072] 52: Arm

[0073] 53: Frame

[0074] 54: Through hole Detailed Implementation

[0075] [1. First Implementation Method]

[0076] [1-1. Structure]

[0077] The following uses Figure 1 and Figure 2 The vibration actuator 1 of the first embodiment will be described. In this embodiment, the vibration actuator 1 is located at a position 1 / 2 of its vibration axis O along a plane of symmetry orthogonal to the central axis. Figure 2 The symbol S) represents components with the same shape set on the boundary. Therefore, for the structure of each component, only the structure of one of the symmetrical shapes is described; for the other, unless there is a special need, the description is omitted by marking it with the same symbol. In addition, in the case of "center of the movable part", it refers to the center in the direction of the vibration axis O in the movable part, specifically the intersection of the vibration axis O and the symmetry plane S. Regarding the inner and outer directions with the vibration axis O as the axis, it is represented as the inner or outer circumference with the vibration axis O as the reference.

[0078] The vibration actuator 1 mainly includes a cylindrical housing 2 forming the outer shell, a housing-side electromagnetic drive unit 3 disposed inside the housing 2, a movable member 4 capable of vibrating through the housing-side electromagnetic drive unit 3, and a leaf spring 5 that elastically supports the movable member 4 to the housing 2.

[0079] The housing 2 includes a cylindrical housing body 10, a cover 11 that closes the openings at both ends, and an inner guide rod 12 disposed on the inner periphery near the opening of the housing body 10. In this embodiment, the housing body 10, the cover 11, and the inner guide rod 12 are respectively made of resin materials such as acrylonitrile butadiene styrene (ABS), but are not limited to resin materials. Terminals 13 for connecting wires (not shown) are formed on the outer surface of the housing body 10.

[0080] The electromagnetic drive unit includes a housing-side electromagnetic drive unit 3 and a movable-part-side electromagnetic drive unit that is freely supported within the housing body 10 for reciprocating motion.

[0081] The electromagnetic drive unit 3 on the housing side includes a magnetic yoke 20 and a coil 21 fixed to the housing 2. That is, a cylindrical magnetic yoke 20 made of soft magnetic material is arranged along its inner circumference in the housing 2, and a coil 21 is installed on the inner circumference of the magnetic yoke 20 in a state of electrical insulation from the magnetic yoke 20.

[0082] The coil 21 is wound along the inner circumference of the yoke 20 and positioned at a predetermined interval relative to the outer circumference of the movable member 4. To prevent contact between the movable member 4 and the coil 21 during vibration, an inner guide rod 12 is fixed to the inner circumference of the housing body 10 to cover the surface of the coil 21 on the movable member 4 side, and a gap is provided between the inner circumferential surface of the inner guide rod 12 and the outer circumferential surface of the movable member 4. The coil 21 can generate a magnetic field by energizing the terminal 13. During assembly, the coil 21 can be temporarily fixed to the yoke 20 or the inner guide rod 12 using adhesives or the like. Alternatively, the coil 21 can be wound outside the housing 2 and inserted into the housing body 10, and then bonded to the yoke 20 or the inner guide rod 12.

[0083] The movable member 4 is disposed within the housing body 10 such that it vibrates along the central axis direction of the cylindrical housing 2, i.e., the vibration axis O. The movable member 4 includes a movable member body having a circular plate-shaped magnet 30, and a weight 32 fixed to the magnet 30. The movable member body has a circular plate-shaped pole piece 31 fixed to the opening side of the housing 2 in the magnet 30, and a weight 32 disposed on the surface of the pole piece 31. The magnet 30 and the pole piece 31 constitute the electromagnetic drive part on the movable member side.

[0084] The magnetization direction of magnet 30 is along the vibration axis O. The pole piece 31 is formed of a soft magnetic material made of metal and is a stamped product comprising a metal plate. Furthermore, the pole piece 31 is attached to magnet 30 by the magnetic attraction of magnet 30 and adhesives, etc. Figure 2 and Figure 3As shown, a protrusion 311 protruding toward the opening of the housing 2 is provided at the center of the electrode 31. In this embodiment, since the protrusion 311 is provided by stamping the electrode 31, a recess 312 is formed on the opposite side of the protrusion 311 of the electrode 31. On the other hand, a recess 321 recessed toward the opening of the housing 2 is formed at the center of the weight 32 corresponding to the protrusion 311. With the protrusion 311 inserted into the recess 321, the electrode 31 and the weight 32 are fixed. The integration of the magnet 30, the electrode 31, and the weight 32 is not limited to installation by means of magnetic attraction, adhesive, or insertion; they can also be integrated by mechanical means such as screwing or other means.

[0085] like Figure 2 As shown, in the movable member 4, the shape of the magnet 30 is smaller in the radial direction than the shape of the pole piece 31 and the weight 32. That is, the outer periphery of the pole piece 31 and the weight 32 is located on the outermost periphery of the movable member 4, and is closest to the inner periphery of the coil 21.

[0086] like Figure 2 and Figure 3 As shown, the weight 32 comprises a non-magnetic body and is a molded article comprising resin and / or metal. In this embodiment, the weight is manufactured by die casting, in which molten metal flows into a mold and solidifies. However, it can also be manufactured by molding methods such as resin molding, embedding metal in resin to adjust weight, hot isostatic pressing, or metal injection molding, in which metal powder is supplied into a mold and solidified. The weight 32 includes: a cylindrical portion 322 extending along the vibration axis O at the center of the weight 32 toward the opening of the housing 2; and a bottomed cylindrical portion, the bottom 323 extending from the root portion of the cylindrical portion 322 (the central side in the direction of the vibration axis O) in a direction orthogonal to the vibration axis, and the cylindrical portion 325 having a U-shaped cross-section opening toward the opening of the housing 2. A recess 321 is formed at the center of the cylindrical portion 322 on the magnet 30 side, recessed toward the opening of the housing 2. The diameter of the recess 321 is formed to be larger than the diameter of the central axis 324 of the weight 32.

[0087] like Figure 2 and Figure 3 As shown, a polygonal central axis 324 protruding towards the vibration axis O is provided at the center of the front end of the cylindrical portion 322 of the weight 32. For example, the central axis 324 of the weight 32 is an equilateral triangle with angles and sides spaced at 120-degree intervals, and the angles are rounded. A cylindrical portion 325 is provided on the outer periphery of the disc-shaped bottom 323, which stands upright towards the leaf spring 5, and three ribs 326 are provided radially at 120-degree intervals on the surface of the bottom 323, extending from the root of the cylindrical portion 322 to the cylindrical portion 325.

[0088] The central portion where the rib 326 meets the cylindrical portion 322 of the weight 32 is thicker than the outer periphery. More specifically, as... Figure 7 As shown, the rib 326 has different heights L1 at the center and L2 at the outer periphery where it connects with the cylindrical portion 322 of the weight 32. Furthermore, the height of the rib 326 is set such that it is highest in the direction of the vibration axis O, so that L1 > L2. Additionally, the upper surface of the rib 326, i.e., the opening side of the shell 2 of the rib 326, is formed by at least two planes at different angles. For example, it could be formed by an inclined surface 326a from approximately one-third of the rib 326 towards the outer periphery, and by a plane 326b parallel to the plane of symmetry S from the end of the inclined surface to the cylindrical portion 325, forming two planes at different angles.

[0089] like Figure 3 As shown, the position of rib 326 is related to the position of the angle of the triangular central axis 324, and the angle is set to be optimal considering the vibration characteristics of the weight 32 and the leaf spring 5. That is, the angle between the weight 32 and the leaf spring 5 in the circumferential direction is determined according to the position of the angle of the central axis 324, but there are parts of the leaf spring 5 that support the weight 32 with different rigidity, such as the arm and the cut-out part. On the other hand, since there are three ribs 326, and the weight distribution of the weight 32 in the circumferential direction is not uniform, the position of the angle of the central axis 324 and the position of rib 326 are set in a way that minimizes the generation of uneven vibration, taking into account the uneven rigidity of the leaf spring 5 and the weight balance of each part of the weight 32. In this embodiment, as shown in FIG6(b), the central axis 324 and rib 326 are arranged such that the vibration axis O is offset by an angle of 60 degrees between the three corners of the central axis 324 and the position of the rib 326.

[0090] The leaf spring 5 comprises one or more metal leaf springs, such as a leaf spring made from a thin sheet of stainless steel in this embodiment. The material of the leaf spring 5 is not limited to metal, but may also be a composite raw material containing resin or fiber. In addition, the material of the leaf spring 5 is ideally a material with excellent durability and flexibility.

[0091] like Figure 4As shown, a polygonal shaft hole 50 is provided at the center of the inner periphery of the leaf spring 5 for the central shaft 324 of the weight 32 to fit into. For example, the shaft hole 50 is an equilateral triangle with angles or sides spaced at 120-degree intervals, and the angles are formed as arcs. The leaf spring 5 is connected to the weight 32 through the shaft hole 50. That is, the weight 32 is aligned with the leaf spring 5 by inserting the central shaft 324 of the weight 32, which is formed as an equilateral triangle, through the shaft hole 50, which is also formed as an equilateral triangle. Furthermore, the central shaft 324 protruding from the surface of the leaf spring 5 is crushed by heating or pressing with a clamp, thereby being riveted together with the surface of the weight 32 overlapping the leaf spring 5. The means of fixing the leaf spring 5 and the weight 32 is not limited to riveting; as long as the polygonal central shaft 324 and the shaft hole 50 are included, other methods such as screwing or bonding can also be used for fixing (connection).

[0092] like Figure 4 As shown, the leaf spring 5 has three arms 52 extending spirally from the support portion 51 provided on its inner periphery toward the outer periphery. Each arm 52 is provided at equal intervals of 120 degrees around the vibration axis O. The outer periphery end of each arm 52 is connected to an annular frame portion 53 provided on the outer periphery of the leaf spring 5 along the inner periphery of the housing body 10.

[0093] As described above, in this embodiment, two leaf springs 5 ​​are arranged symmetrically with a plane of symmetry as the boundary. The helical directions of the arms 52 of the two leaf springs 5 ​​are opposite to each other. Therefore, when the actuator vibrates, the movable member 4 receives torques in opposite directions from the two leaf springs 5, so even if it reciprocates along the vibration axis O, it will not rotate around the vibration axis O.

[0094] like Figure 4 As shown, a flange portion 14 protruding radially inward toward the end face of the cylindrical housing body 10 is provided, and three protrusions 15 extending along the vibration axis O are provided at 120-degree intervals on the flange portion 14. Three through holes 54 for inserting the protrusions 15 are provided at 120-degree intervals on the frame portion 53 of the outer periphery of the leaf spring 5. In this case, as shown in FIG6(a), the shaft hole 50 and the three through holes 54 of the leaf spring 5 are arranged with an angular offset of 30 degrees between the three corners of the triangular central axis 324 of the weight 32 and the three corners of the triangular shaft hole 50 of the leaf spring 5 and the positions of the three through holes 54 of the leaf spring 5, with the vibration axis O as the reference.

[0095] With each protrusion 15 inserted into each through hole 54, a clamp is used to heat or press the front end of each protrusion 15 and crush it, thereby riveting it so that the frame portion 53 of the leaf spring 5 coincides with the end face of the housing body 10. The fixing means between the frame portion 53 and the leaf spring 5 is not limited to riveting, but can also be fixed by other methods such as screwing or bonding.

[0096] The leaf spring 5 thus constructed is capable of elastic deformation within a specified range in the direction of the vibration axis O and the plane of symmetry S. Furthermore, this specified range corresponds to the amplitude range of the movable element 4 when typically used as a vibration actuator 1. Therefore, the specified range is at least the area where the leaf spring 5 does not contact the housing 2, and is not greater than the limit of the elastic deformation of the leaf spring 5.

[0097] In this embodiment, a damping member 41 for controlling the vibration characteristics of the leaf spring 5 is provided. For example... Figure 4 As shown, the damping member 41 is plate-shaped, extending from the support portion 51 of the leaf spring 5 to each arm portion 52 within a certain range, and is fixed to one side of the leaf spring 5. The damping member 41 comprises a first adhesive layer formed by an adhesive, a PE layer formed by polyethylene (PE), a second adhesive layer formed by an adhesive, and an elastomer layer formed by an elastomer, all laminated on the leaf spring 5. Suitable elastomers are thermoplastic polyurethane (TPU), but it is not limited to this. Damping of the leaf spring 5 is achieved through the elastic deformation of the damping member 41, specifically through the shear deformation of the PE layer or adhesive layer and the bending deformation of the elastomer layer. The means of fixing the damping member 41 to the leaf spring 5 is not limited to the aforementioned adhesive; other means of fixing, such as heat-welding the resin-made damping member 41 to the leaf spring 5, may also be used.

[0098] [1-2. The Role of the Implementation Method]

[0099] The vibration actuator 1 configured as described above, when not energized to coil 21, such as Figure 2 As shown, the movable member 4, supported by the leaf spring 5, is located at the center in the direction of the vibration axis O.

[0100] When the movable part 4 vibrates, alternating current is applied to the coil 21 via terminal 13 in a direction that alternately generates magnetic fields of opposite polarities. That is, the same polarity is generated in adjacent portions of the coil 21. For example, in Figure 8 In the case of the polarity shown, the movable part 4 produces the other side in the direction of the vibration axis O, as indicated by the solid arrow A. Figure 8 If the thrust from below (in the middle) reverses the current flowing to coil 21, then on the movable part 4, a force is generated in the direction of the vibration axis O as indicated by the solid arrow B. Figure 8 The thrust from above the coil 21. Thus, if alternating current is applied to the coil 21, the movable member 4 will vibrate along the vibration axis O while being subjected to forces generated by the leaf springs 5 ​​from both sides.

[0101] The thrust generated by the movable member 4 is basically based on the thrust given by Fleming's left-hand rule. In this embodiment, since the two coils 21, which are arranged symmetrically, are fixed to the housing 2, the movable member 4, on which the magnet 30 is mounted, also generates a thrust as a reaction force to the force generated by the two coils 21.

[0102] Therefore, the weight 32 is subjected to a force that acts along the vibration axis O and a force that acts along the symmetry plane S of the magnetic flux of the magnet 30, causing it to rotate around the vibration axis O. At this time, the angle of the central axis 324 of the equilateral triangle set on the weight 32 becomes the anti-rotation element of the weight 32, and the movable element 4 vibrates along the vibration axis O.

[0103] [1-3. Effects of the Implementation Method]

[0104] (1) In this embodiment, when the protrusion 311 of the movable member 4 is inserted into the recess 321 of the weight 32, the movable member 4 and the weight 32 are fixed. Therefore, it is not necessary to provide a protrusion on the weight 32, and the formation of the weight 32 becomes easier.

[0105] (2) In this embodiment, with the protrusion 311 of the pole piece 31 inserted into the recess 321 of the weight 32, the pole piece 31 and the weight 32 are fixed. Therefore, there is no through hole in the pole piece 31, so the magnetic lines of force from the magnet 30 are captured in the entire area of ​​the pole piece 31 and flow into the pole piece 31. Therefore, the magnetic lines of force will not leak from the magnet 30, and the movable member 4 can be reciprocated effectively by utilizing the magnetic force generated in the coil 21, thereby obtaining excellent vibration characteristics.

[0106] (3) A recess 321 is provided in the center of the weight 32, which is recessed toward the opening of the housing 2. Therefore, the molding component can easily flow into the mold during molding, and even if it is small and complex in shape, the manufacturing of the weight 32 becomes easy, and a vibration actuator with excellent vibration characteristics can be provided.

[0107] (4) In this embodiment, the diameter of the recess 321 of the weight 32 is larger than the diameter of the central axis 324 of the weight 32. Therefore, the molding component can easily flow into the mold during molding, and the manufacture of the weight 32 is easy even if it is small and has a complex shape. In addition, when riveting the central axis 324 of the weight 32 that protrudes from the surface of the leaf spring 5, the area of ​​the plane directly below the riveting shape is increased, thereby enabling stable fixing. Furthermore, since the diameter of the recess 321 of the weight 32 is larger than the diameter of the central axis 324 of the weight 32, it is also easy to manufacture a protrusion like the central axis 324.

[0108] (5) In this embodiment, the weight 32 has a bottomed cylindrical portion, namely, a bottom 323 extending in a direction orthogonal to the vibration axis O, and a bottomed cylindrical portion 325 opening in the direction of the opening of the housing 2, which is a U-shaped cross-section. Therefore, even when an external impact is applied, the cylindrical portion 325 of the weight 32 contacts the inner guide rod 12, preventing the movable part 4 from contacting the coil 21, thereby preventing malfunction or abnormal noise.

[0109] (6) In this embodiment, a cylindrical portion 322 extending along the vibration axis O toward the opening side of the housing 2 is integrally provided at the center of the weight 32 and the bottomed cylindrical portion. Therefore, a vibration actuator with a weight 32 that is easy to manufacture with optimal weight and high strength and excellent vibration characteristics can be provided.

[0110] (7) In this embodiment, the outer periphery of the cylindrical portion 325 is located at the outermost periphery of the movable member 4. Therefore, even when an external impact or the like is applied, the cylindrical portion 325 of the weight 32 is in contact with the inner guide rod 12, thereby preventing the movable member 4 from contacting the coil 21.

[0111] (8) In this embodiment, ribs 326 are provided radially at equal intervals between the cylindrical portion 322 and the cylindrical portion 325. Therefore, even when the cylindrical portion 325 is formed with a thin wall, high strength can be maintained, and a vibration actuator with excellent vibration characteristics can be provided.

[0112] (9) In this embodiment, the center portion of the weight 32 that connects with the cylindrical portion 322 is made thicker than the outer periphery. Therefore, during the molding of the weight 32, the forming component can easily flow into the mold, making the manufacturing of the weight 32 easier. In addition, since the center portion of the weight 32 is heavier, the overall weight balance of the movable part can be improved. Furthermore, when riveting the central shaft 324 of the weight 32 protruding from the surface of the leaf spring 5, the thick center portion of the weight 32 allows for stable riveting.

[0113] (10) In this embodiment, the upper surface of the rib 326, i.e. the opening side of the shell 2 of the rib 326, is formed by at least two planes at different angles. Therefore, during the molding of the weight 32, the molding component is more likely to flow into the mold, and even if it is small and has a complex shape, the manufacturing of the weight 32 becomes easier.

[0114] [2. Other Implementation Methods]

[0115] As described above, several embodiments of the present invention have been illustrated, but this is not intended to limit the scope of the invention. As listed below, the invention can be implemented in various other forms without departing from its spirit, and various omissions, substitutions, and modifications are possible. Furthermore, these embodiments, combinations thereof, and variations thereof are included within the scope or spirit of the invention, and are included within the scope of the claims and their equivalents. The following are examples of embodiments included in the present invention.

[0116] (1) For example, in the embodiment, the protrusion 311 of the electrode 31 and the recess 321 of the weight 32 are both provided in the center, but they do not necessarily need to be provided in the center. In addition, the protrusion 311 and the recess 321 are not limited to one; as long as the number of the two is equal, multiple protrusions can be provided.

[0117] (2) In the embodiment described above, ribs 326 are provided radially at equal intervals between the cylindrical portion 322 and the cylindrical portion 325. However, as long as the ribs are used to reinforce the strength of the cylindrical portion 322 or the cylindrical portion 325, they do not necessarily need to be at equal intervals. In addition, the shape of the ribs is not limited to radial, but may also be lattice-shaped or spiral-shaped, etc.

[0118] (3) In the embodiment described above, the rib 326 is formed such that the central part of the weight 32 that is connected to the cylindrical part 322 is thicker than the outer periphery, that is, the central part of the weight 32 that is connected to the cylindrical part 322 has the highest height in the direction of the vibration axis O, or it can be formed such that the central part of the weight 32 that is connected to the cylindrical part 322 has the longest length in the direction of the symmetry plane S.

[0119] (4) In the embodiment described above, the leaf spring 5 has a damping member 41, but it may not necessarily have a damping member.

[0120] (5) The housing 2 of the embodiment is cylindrical and the movable part 4 is generally cylindrical, but the shape of the housing and the movable part is not limited to this, and may also be polygonal or other shapes.

[0121] (6) In the embodiment described above, a protrusion 311 is provided on the pole piece 31 of the movable member. However, a protrusion may also be provided on the surface of other components of the movable member, such as the magnet 30, or on the surface of other components when the pole piece 31 is covered or stacked on the weight side.

Claims

1. A vibration actuator, characterized in that... include: A cylindrical shell having at least one opening; A coil is disposed in the housing; The movable part vibrates along the vibration axis of the housing; as well as Leaf spring, providing elastic support for the movable member. The movable element includes a magnet, a movable element body, and a weight. The movable element body has a pole piece fixed to the at least one opening side of the housing within the magnet. The weight is fixed to the pole piece at the at least one opening side of the housing and is also fixed to the leaf spring. A protrusion is provided at the center of the electrode sheet, protruding toward at least one opening of the housing. A recess is provided at the center of the weight, facing the at least one opening of the housing. With the protrusion inserted into the recess, the electrode and the weight are fixed.

2. The vibration actuator according to claim 1, characterized in that, The cylindrical shell has openings at both ends. The leaf spring elastically supports the movable parts of the openings at both ends of the cylindrical housing. The movable member has pole pieces fixed to the magnet and weights fixed to the pole pieces at the openings at both ends of the housing, respectively. The weights are fixed to the leaf springs at the openings at both ends of the housing. Each electrode has a protrusion at its center that protrudes toward the openings at both ends of the housing. Each of the weights has a recessed portion at its center, which is recessed towards the openings at both ends of the housing. With each of the protrusions inserted into the recess, the electrode and the weight are fixed.

3. The vibration actuator according to claim 1 or 2, characterized in that, The diameter of the recessed portion of the weight is greater than the diameter of the central axis of the weight.

4. The vibration actuator according to claim 1, characterized in that, The weight has a bottomed cylindrical portion, the bottom of which extends in a direction orthogonal to the vibration axis, and the cylindrical portion of which opens toward the opening of the housing.

5. The vibration actuator according to claim 4, wherein, The weight has a cylindrical portion integrally formed with the bottomed cylindrical portion at its center, and the cylindrical portion extends along the vibration axis toward the opening of the shell.

6. The vibration actuator according to claim 4 or 5, wherein, The outer periphery of the bottomed cylindrical portion is located on the outermost periphery side of the movable member.

7. The vibration actuator according to claim 5, characterized in that, The weight has ribs between it and the cylindrical portion, starting from the root of the cylindrical portion.

8. The vibration actuator according to claim 7, characterized in that, The central portion of the rib is thicker than the outer periphery of the rib.

9. The vibration actuator according to claim 7, characterized in that, The surface of the rib on the opening side of the housing is formed by at least two planes at different angles.

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