Vibration actuator and electric device

Abstract

To achieve both manufacturing easiness and reliability with respect to drop impact even when a vibration actuator is downsized.SOLUTION: A vibration actuator includes: a fixation part having a thickness in a vertical direction and including a magnet fixed to a base; and a movable part arranged in a periphery of the fixation part, supported by a spring so as to be able to vibrate in the vertical direction, including a coil, and configured to vibrate in the vertical direction due to a driving force generated by mutual action of the electrified coil and the magnet. The spring has a truncated pyramid shape. An outside part of the spring connects to an outer peripheral part of the movable part. An inside part of the spring is connected to the base. The inside part has an opening to which an end portion of the fixation part in the vertical direction is inserted.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a vibration actuator and an electrical device equipped with the same. [Background technology]

[0002] Portable or wearable electrical devices with a vibration function are generally equipped with an actuator (vibration actuator) as a vibration generating source. The electrical device can notify the user of an incoming call or give a stimulus by driving the vibration actuator to transmit vibration to the user and have the user feel it. Note that portable or wearable electrical devices include mobile terminals such as mobile phones, smartphones, and smart watches, as well as various health care devices and beauty devices that provide massages and the like to users.

[0003] As an example of a conventional vibration actuator, there is a linear resonant actuator (LRA) described in Patent Document 1, for example. The linear resonant actuator described in Patent Document 1 has a cylindrical fixed part extending in the vertical direction, an annular movable part arranged around a permanent magnet, an elastic member, and a flexible printed circuit (FPC: Flexible Printed Circuits) in a cylindrical case with a bottom and a lid. The fixed part includes a magnet (permanent magnet), and the movable part includes a coil, a weight, and a yoke. The case has a disk-shaped base that is the bottom of the case, and a cylindrical cover with a lid that covers the top of the base. A circular protrusion is provided in the center of the base, and the lower end of the cylindrical fixed part is inserted and fixed inside the protrusion. The upper end of the fixed part is bonded to the upper part of the case.

[0004] In the cylindrical case, spaces are provided above and below the movable part to form the movable part's range of motion, with an elastic member disposed in the upper space and a flexible board disposed in the lower space. The flexible board is connected to the coil from below the movable part to supply power to the coil. The elastic member is a truncated cone-shaped spring, with an outer periphery of the spring fixed to the outer periphery of the upper part of the case and an inner periphery of the spring protruding downward from the outer periphery of the spring connected to the inner periphery of the upper part of the movable part, supporting the movable part so that it can vibrate in the vertical direction.

[0005] When the coil receives power, the magnetic field generated in the coil interacts with the magnetic field of the permanent magnet to generate a magnetic driving force that causes the movable part to vibrate up and down. The movable part vibrates up and down due to the generated magnetic driving force and the reaction force of the spring. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2016-152734 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the conventional vibration actuator, in order to provide a protrusion for fixing the fixing part at the center of the bottom of the case, it is necessary to process the base as the bottom of the case. On the other hand, due to the constraints on the installation space of the vibration actuator in portable or wearable electrical devices, further miniaturization of the vibration actuator is desired. When miniaturization of the vibration actuator is desired, for example, in the conventional vibration actuator, fine processing is required for the base. In other words, the conventional vibration actuator has a problem in terms of ease of manufacture. In addition, when the vibration actuator is applied to a portable or wearable electrical device, the risk of receiving a drop impact increases, and ensuring reliability against drop impact becomes an issue.

[0008] An object of the present invention is to provide a vibration actuator that is compact yet easy to manufacture and reliable against drop impacts, and an electrical device equipped with such a vibration actuator. [Means for solving the problem]

[0009] One aspect of the vibration actuator according to the present invention is a fixed portion including a magnet, the fixed portion having a thickness in a vertical direction and fixed to a base; a movable part that is disposed around the fixed part, is supported by a spring so as to be capable of vibrating in the vertical direction, includes a coil, and vibrates in the vertical direction by a driving force generated by an interaction between the coil and the magnet when a current is applied, The spring has a frustum shape, an outer portion of the spring is connected to the outer periphery of the movable part, and an inner portion of the spring is connected to the base, and the inner portion has an opening into which the end of the fixed part in the vertical direction is inserted.

[0010] One aspect of the electrical device according to the present invention is A portable or wearable electrical device incorporating the vibration actuator described above. Effect of the Invention

[0011] According to the present invention, even if the vibration actuator is miniaturized, it is possible to achieve both ease of manufacture and reliability against drop impact. [Brief description of the drawings]

[0012] [Figure 1A] FIG. 1A is a perspective view showing the appearance of a vibration actuator according to an embodiment. [Figure 1B] FIG. 1B is a perspective view showing the vibration actuator according to the embodiment, excluding the outer casing. [Diagram 2] FIG. 2 is an exploded view showing the vibration actuator according to the embodiment. [Diagram 3]FIG. 3 is a diagram showing a schematic cross-sectional configuration of a vibration actuator according to an embodiment. [Figure 4] FIG. 4 is an enlarged view of a connecting portion between a base, a fixed portion, and a spring in a vibration actuator according to an embodiment, for explaining the connecting portion. [Diagram 5] FIG. 5 is a view showing the connection portion between the base, the fixed portion, and the spring in a vibration actuator according to an embodiment, viewed from below, for explaining the connection portion. [Figure 6] FIG. 6 is a diagram showing a mobile terminal equipped with a vibration actuator according to an embodiment. [Figure 7] FIG. 7 is a diagram showing a wearable terminal equipped with a vibration actuator according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0014] FIG. 1A is a perspective view showing the appearance of a vibration actuator according to the present embodiment, and FIG. 1B is a perspective view showing the vibration actuator according to the present embodiment excluding the outer casing. FIG. 3 is a schematic view showing a cross-sectional configuration of a vibration actuator according to an embodiment. FIG. 4 is an enlarged view of a connection portion between a base, a fixed portion, and a spring in a vibration actuator according to an embodiment, for explaining the connection portion. FIG. 5 is a view of the connection portion between a base, a fixed portion, and a spring as viewed from below in a vibration actuator according to an embodiment, for explaining the connection portion.

[0015] In the following description, the terms "upper" and "lower" in terms such as "upper side" and "lower side" are used for the sake of convenience to facilitate understanding of the configuration and behavior of the vibration actuator 1 according to this embodiment. When the vibration actuator 1 is mounted on an electrical device (see Figs. 6 and 7), the "upper" and "lower" described here may be reversed, may be left or right, or may be oblique. Incidentally, in this embodiment, the up-down direction is the vibration direction of the movable body in the vibration actuator 1, with the "upward direction" being one of the vibration directions and the "downward direction" being the other of the vibration directions. In other words, the vibration actuator 1 is a linear actuator that vibrates the movable part 13 linearly in the up-down direction.

[0016] In the following description, the direction extending radially or centrifugal from the center of the vibration actuator 1 when the vibration actuator 1 is viewed in a plan view from above and below is referred to as the "radial direction." Furthermore, "inside" as in "inner side" refers to a position in the radial direction closer to the center of the vibration actuator 1 when viewed in a plan view, and "outside" as in "outer side" refers to a position in the radial direction farther from the center of the vibration actuator 1 when viewed in a plan view. Furthermore, unless otherwise specified, the "circumferential direction" refers to the direction extending around the center of the vibration actuator 1 when viewed in a plan view.

[0017] Furthermore, it goes without saying that the expressions relating to shapes used in the following description are expedient expressions for the purpose of simple outline description, and do not necessarily apply to geometrically accurate definitions of figures. The shapes of the entire device or each component part described herein are merely examples, and the present invention is not limited to the shapes exemplified in this embodiment.

[0018] The vibration actuator 1 is mounted as a vibration generating source in a portable or wearable electric device, and realizes the vibration function of the electric device. Examples of electric devices include a mobile terminal such as a smartphone (for example, the mobile terminal M shown in FIG. 6), and a wearable smart device of a ring type or a wristwatch type (for example, the wearable terminal W shown in FIG. 7). Electric devices in which the vibration actuator 1 can be mounted also include health care devices and beauty devices that provide massages and the like to users. The vibration actuator 1 is mounted in various electric devices, and the vibration actuator 1 itself vibrates due to the vibration of the internal movable part 13, thereby notifying the user of an incoming call or providing a physical stimulus.

[0019] The vibration actuator 1 has a cylindrical case 10 , a base 11 , a fixed part 12 , a movable part 13 , a flexible substrate 14 , and a spring 15 .

[0020] The cylindrical case 10 has a hollow portion that is rectangular in plan view and penetrates in the vertical direction. In other words, the cylindrical case 10 is a square cylindrical body. The cylindrical case 10 is made of a non-magnetized magnetic body, and functions as an outer yoke (fixed yoke) in the vibration actuator 1. Examples of materials for the magnetic body include permalloy.

[0021] In this embodiment, the "rectangular shape in plan view" typically refers to a square shape in plan view. This also applies to the following description.

[0022] The base 11 includes a first base 11-1 and a second base 11-2. Both the first base 11-1 and the second base 11-2 are flat plates having a rectangular shape in a plan view. The first base 11-1 functions as a lid (which may be called a top surface) that closes the opening at the upper end of the cylindrical case 10, and the second base 11-2 functions as a lid (which may be called a bottom surface) that closes the opening at the lower end of the cylindrical case 10. In addition, both the first base 11-1 and the second base 11-2 are made of a non-magnetized magnetic material, and function as an actor yoke (fixed yoke) together with the cylindrical case 10 in the vibration actuator 1. Examples of materials for the magnetic material include permalloy.

[0023] The box formed by combining the cylindrical case 10 and the base 11 is the outer housing of the vibration actuator 1. The cylindrical case 10 and the base 11 are fixed to each other by welding, but the fixing method may be bonding with an adhesive or fastening with a fastening member (e.g., a screw). The outer housing is attached to an external device (portable or wearable electrical equipment) by a desired fixing method such as bonding and fastening.

[0024] Since the first base 11-1 and the second base 11-2 have the same shape, they function as a lid (which may also be called a top surface) that closes the opening at the upper end of the cylindrical case 10, and the second base 11-2 can utilize a common part as a lid that closes each of the lower end and the opening at the lower end of the cylindrical case 10.

[0025] In this embodiment, the term "same shape" does not include "similar" meaning that the shapes are the same but the sizes (dimensions) are different, but includes "congruent" meaning that the shapes are the same as well as the sizes (dimensions). This point is the same in the following explanations.

[0026] The fixed portion 12 includes a first fixed portion 12-1 and a second fixed portion 12-2. The first fixed portion 12-1 has a first magnet 12-1a, and the second fixed portion 12-2 has a second magnet 12-2a. The fixed portion 12 may be a single part, but in this embodiment, from the viewpoint of ease of manufacture, the fixed portion 12 includes a pair of parts (the first fixed portion 12-1 and the second fixed portion 12-2) having the same shape. This point will be described later.

[0027] The fixed portion 12 constitutes a fixed body of the vibration actuator 1 together with the cylindrical case 10 and the base 11 which constitute the outer housing.

[0028] The first magnet 12-1a and the second magnet 12-2a are each a prism (rectangular parallelepiped or cube) that is rectangular in plan view (more specifically, square in plan view) and has a thickness (which may be called height) in the vertical direction. The first magnet 12-1a and the second magnet 12-2a have the same shape. The magnetization direction of the first magnet 12-1a and the second magnet 12-2a is the vertical direction (which may be called thickness direction or height direction). In this embodiment, the upper end 12-1c side of the first magnet 12-1a is magnetized to the S pole, and the lower end side is magnetized to the N pole. Also, the lower end 12-2c of the second magnet 12-2a is magnetized to the S pole, and the upper end side is magnetized to the N pole.

[0029] The first magnet 12-1a and the second magnet 12-2a are fixed to the first base 11-1 and the second base 11-2, respectively, by bonding with an adhesive.

[0030] The first base 11-1 and the second base 11-2 close the cylindrical case 10 from above and below, with the first magnet 12-1a and the second magnet 12-2a facing each other (more specifically, with the same poles facing each other). An adhesive is applied to the gap between the facing portions of the first magnet 12-1a and the second magnet 12-2a. This makes it possible to strengthen the fixing strength between the upper and lower halves of the vibration actuator 1.

[0031] The movable part 13 is an annular body arranged around the fixed part 12. The movable part 13 has an air core coil 13-1 and a weight 13-2. The air core coil 13-1 and the weight 13-2 are both annular bodies having a rectangular shape in a plan view (more specifically, a square shape in a plan view). The air core coil 13-1 is arranged relatively on the inside in the radial direction, and the weight 13-2 is arranged relatively on the outside in the radial direction. The inner peripheral surface of the air core coil 13-1 has a rectangular shape in a plan view corresponding to the rectangular shapes in a plan view of the magnet outer peripheral parts 12-1b and 12-2b of the first magnet 12-1a and the second magnet 12-2a, but the radial size is slightly larger than that of the magnet outer peripheral parts 12-1b and 12-2b. Therefore, the air core coil 13-1 faces the magnet outer peripheral parts 12-1b and 12-2b with a small gap therebetween. The outer peripheral surface of the air-core coil 13-1 is fixed to the outer peripheral surface of the weight 13-2 by adhesive.

[0032] Incidentally, the air core coil 13-1 can be replaced with, for example, a wound coil wound around a bobbin, etc. However, from the viewpoint of minimizing the number of parts and minimizing the size of the device, it is preferable to use an air core coil 13-1 that does not require a holding member such as a bobbin.

[0033] The weight 13-2 is made of a material with a high specific gravity and functions as a weight that provides the movable part 13 with a desired mass. The material with a high specific gravity may be a magnetic material. Examples of such materials include tungsten. When the weight 13-2 is a non-magnetized magnetic body, the weight 13-2 can function as an inner yoke (movable yoke). The outer peripheral surface of the weight 13-2 has a rectangular shape in a plan view that corresponds to the rectangular shape of the hollow part of the cylindrical case 10 in a plan view, but the radial size is slightly smaller than that of the hollow part of the cylindrical case 10. Therefore, the weight 13-2 faces the cylindrical case 10 with a small gap therebetween.

[0034] The flexible substrate 14 is a circuit board for passing electricity (for supplying a drive signal) to the air core coil 13-1. Since the circuit board needs to be flexible in order to be connected to the air core coil 13-1 that constitutes the movable part 13, the flexible substrate 14 is used.

[0035] In this embodiment, the flexible substrate 14 has a ring-shaped connection portion 14a at its tip and a band-shaped extension portion 14b extending from the connection portion 14a to its rear end. The connection portion 14a surrounds the outer periphery of the fixed portion 12 and is fixed to the upper outer periphery 13-2a of the weight 13-2. The connection portion 14a has a terminal that connects to the air core coil 13-1. The extension portion 14b has wiring for electrically connecting the terminal provided on the connection portion 14a to an external device. The extension portion 14b extends to the outside of the vibration actuator 1 through a side opening 10a provided in the cylindrical case 10.

[0036] The spring 15 includes a first spring 15-1 and a second spring 15-2. The first spring 15-1 and the second spring 15-2 have the same shape. The first spring 15-1 has two first flexible parts 15-1c each having a spiral shape extending from the first inner part 15-1a to the first outer part 15-1b. The second spring 15-2 has two second flexible parts 15-2c each having a spiral shape extending from the second inner part 15-2a to the second outer part 15-2b.

[0037] In this embodiment, the first spring 15-1 and the second spring 15-2 are flat before being assembled, i.e., leaf springs. Since the first spring 15-1 and the second spring 15-2 are manufactured as leaf springs, they can be easily manufactured by punching a flat metal plate, such as a stainless steel plate, into a spiral shape.

[0038] However, in this embodiment, the first spring 15-1 and the second spring 15-2 have a frustum shape after assembly, as shown in Fig. 1B and Fig. 3. The frustum shape of the first spring 15-1 is such that the first inner portion 15-1a protrudes upward relative to the first outer portion 15-1b. The frustum shape of the second spring 15-2 is such that the second inner portion 15-2a protrudes downward relative to the second outer portion 15-2b.

[0039] The thickness of the first spring 15-1 is sufficiently thin compared to the space secured as a movable range above the movable part 13 in the cylindrical case 10. Therefore, when the first inner part 15-1a and the first outer part 15-1b are connected to the radial center part of the first base 11-1 and the upper outer peripheral part 13-2a of the movable part 13, respectively, the first spring 15-1 naturally becomes frustum-shaped.

[0040] The thickness of the second spring 15-2 is sufficiently thin compared to the space secured as a movable range below the movable part 13 in the cylindrical case 10. Therefore, by connecting the second inner part 15-2a and the second outer part 15-2b to the radial center part of the second base 11-2 and the lower outer peripheral part 13-2b of the movable part 13, respectively, the second spring 15-2 naturally becomes frustum-shaped.

[0041] The first inner portion 15-1a of the first spring 15-1 is connected to the first base 11-1. The second inner portion 15-2a of the second spring 15-2 is connected to the second base 11-2. In this embodiment, the first inner portion 15-1a and the second inner portion 15-2a are fixed to the first base 11-1 and the second base 11-2, respectively, by welding. That is, the first inner portion 15-1a of the first spring 15-1 is the fixed end of the first spring 15-1, and the second inner portion 15-2a of the second spring 15-2 is the fixed end of the second spring 15-2.

[0042] A first outer portion 15-1b of the first spring 15-1 is connected to an upper outer peripheral portion 13-2a of the movable portion 13. A second outer portion 15-2b of the second spring 15-2 is connected to a lower outer peripheral portion 13-2b of the movable portion 13.

[0043] More specifically, in the first spring 15-1, the first outer end portions 15-1e of the two first flexible portions 15-1c are connected to two diagonal corners of the upper outer peripheral portion 13-2a. In this manner, the first outer end portions 15-1e of the two first flexible portions 15-1c can support the rectangular movable portion 13 at positions furthest outward from the radial center portion, so that the horizontal posture of the rectangular movable portion 13 can be stably maintained.

[0044] In the second spring 15-2, the second outer end portions 15-2e of the two second flexible portions 15-2c are connected to two diagonal corner portions of the lower outer peripheral portion 13-2b. In this manner, the second outer end portions 15-2e of the two second flexible portions 15-2c can support the rectangular movable portion 13 at a position farthest outward from the radial center portion, so that the horizontal posture of the rectangular movable portion 13 can be stably maintained.

[0045] Here, the weight 13-2 is provided with protrusions 13-2c that protrude upward and downward at the four corners of the upper outer peripheral portion 13-2a and the lower outer peripheral portion 13-2b. The first outer end portion 15-1e of the first spring 15-1 and the second outer end portion 15-2e of the second spring 15-2 are fixed by welding to the protrusions 13-2c at the corresponding positions. In this way, since the fixing portions of the first outer end portion 15-1e and the second outer end portion 15-2e of the movable portion 13 protrude, it is easy to fix the first outer end portion 15-1e and the second outer end portion 15-2e to the movable portion 13. In addition, since the protrusions 13-2c are provided at all corners, the protrusions 13-2c can be arranged at positions corresponding to the two second outer end portions 15-1e and the two second outer end portions 15-2e regardless of the orientation of the movable portion 13 arranged in the cylindrical case 10. Furthermore, in weight 13-2, the location to which spring 15 is connected and the location to which flexible substrate 14 is connected can be distinguished by the projections and recesses.

[0046] The diagonal line on which the two corners of the upper outer peripheral portion 13-2a to which the two first outer ends 15-1e are connected are located intersects with the diagonal line on which the two corners of the lower outer peripheral portion 13-2b to which the two second outer ends 15-2e are connected. This allows the springs 15, in combination with the upper first spring 15-1 and the lower second spring 15-2, to support the rectangular movable portion 13 in both diagonal directions. This further stabilizes the horizontal position of the movable portion 13.

[0047] The first inner portion 15-1a has a first opening 15-1d. The first opening 15-1d has a rectangular shape in plan view corresponding to the rectangular shape in plan view of the magnet outer periphery 12-1b of the first fixed portion 12-1 (first magnet 12-1a). The upper end portion 12-1c of the first magnet 12-1a is inserted into the first opening 15-1d. Therefore, the first spring 15-1 can function as a positioning member that determines the fixed position of the first magnet 12-1a. This makes it unnecessary to perform fine processing for fixing the first fixed portion 12-1 to the first base 11-1, and therefore makes manufacturing easier. As a result, the dimensional stability of the vibration actuator 1 can be improved, and therefore the vibration characteristics can be stabilized and improved.

[0048] Moreover, with the first opening 15-1d surrounding the magnet outer peripheral portion 12-1b, the first inner portion 15-1a is connected to the first base 11-1 included in the fixed body. Therefore, the first spring 15-1 can also function as a support member that supports the first fixed portion 12-1 (first magnet 12-1a). As a result, the first fixed portion 12-1 can be fixed not only by the first base 11-1 but also by the first spring 15-1, so that the fixing strength of the first fixed portion 12-1 can be strengthened. Therefore, the reliability of the vibration actuator 1 against drop impacts and the like can be improved.

[0049] The second inner portion 15-2a has a second opening 15-2d. The second opening 15-2d has a rectangular shape in plan view corresponding to the rectangular shape in plan view of the magnet outer periphery 12-2b of the second fixed portion 12-2 (second magnet 12-2a). The lower end portion 12-2c of the second magnet 12-2a is inserted into the second opening 15-2d. Therefore, the second spring 15-2 can function as a positioning member that determines the fixed position of the second magnet 12-2a. This makes it unnecessary to perform fine processing for fixing the second fixed portion 12-2 to the second base 11-2, and therefore makes manufacturing easier. As a result, the dimensional stability of the vibration actuator 1 can be improved, and therefore the vibration characteristics can be stabilized and improved.

[0050] Moreover, with the second opening 15-2d surrounding the magnet outer peripheral portion 12-2b, the second inner portion 15-2a is connected to the second base 11-2 included in the fixed body. Therefore, the second spring 15-2 can also function as a support member that supports the second fixed portion 12-2 (second magnet 12-2a). As a result, the second fixed portion 12-2 can be fixed not only by the second base 11-2 but also by the second spring 15-2, so that the fixing strength of the second fixed portion 12-2 can be strengthened. Therefore, the reliability of the vibration actuator 1 against drop impacts and the like can be improved.

[0051] In the vibration actuator 1 having the above configuration, when an AC driving current is input as a driving signal to the air core coil 13-1, a driving force for upward movement and a driving force for downward movement are generated alternately and repeatedly in the movable part 13 according to the frequency (driving frequency) of the driving current. This causes the movable part 13 to vibrate. In this embodiment, the thrust acts in the vertical direction, so the movable part 13 vibrates linearly in the vertical direction. The above-mentioned driving force is a thrust that follows Fleming's left-hand rule and is generated by the interaction between the energized air core coil 13-1 and the first magnet 12-1a and second magnet 12-2a.

[0052] In this embodiment, the movable part 13 is elastically supported by the first spring 15-1 and the second spring 15-2 so as to be able to vibrate in the vertical direction. Therefore, when the movable part 13 moves upward or downward from the center position of the vibration, the deformed first flexible part 15-1c of the first spring 15-1 and the second spring 15-2 generate a restoring force to return to their original shapes, and transmit this force to the movable part 13. The movable part 13 is biased in the opposite direction by this force. That is, the movable part 13 moves downward if it has moved upward, and moves upward if it has moved downward, so as to return to the center position of the vibration.

[0053] When an AC wave having a frequency equal to the resonant frequency of movable part 13 is input to air core coil 13-1, movable part 13 enters a resonant state. That is, by inputting an AC wave having a frequency equal to the resonant frequency of movable part 130 to air core coil 13-1, movable part 13 can be vibrated efficiently.

[0054] As described above, according to this embodiment, the vibration actuator 1 has a fixed part 12 and a movable part 13. The fixed part 12 has a thickness in the vertical direction and includes a magnet (at least one of a first magnet 12-1a and a second magnet 12-2a) fixed to the base 11. The movable part 13 is disposed around the fixed part 12, is supported by a spring 15 so as to be able to vibrate in the vertical direction, includes a coil (air-core coil 13-1), and vibrates in the vertical direction by a driving force generated by an interaction between the energized coil and the magnet. The spring 15 has a frustum shape. An outer part of the spring 15 (at least one of a first outer part 15-1b and a second outer part 15-2b) is connected to an outer periphery of the movable part 13 (at least one of an upper outer periphery 13-2a and a lower outer periphery 13-2b). An inner part of the spring 15 (at least one of a first inner part 15-1a and a second inner part 15-2a) is connected to the base 11. The inner portion of the spring 15 (at least one of the first inner portion 15-1a and the second inner portion 15-2a) has an opening (at least one of the first opening 15-1d and the second opening 15-2d) into which the end portion (upper end portion 12-1c or lower end portion 12-2c) of the fixed portion 12 in the vertical direction is inserted.

[0055] According to the above configuration, the inner part of the spring 15 corresponding to the radial center part where the fixed part 12 is located is fixed to the base 11. This allows the spring 15 to support the upper and lower ends of the fixed part 12. Specifically, as described above, an opening is provided in the inner part of the spring 15, and the upper and lower ends of the fixed part 12 are inserted into this opening. Since the upper and lower ends of the fixed part 12 are fixed to the base 11 with the opening of the inner part of the spring 15 surrounding the outer periphery of the fixed part 12, the fixed part 12 can be fixed not only by the base 11 but also by the spring 15, and the fixing strength of the fixed part 12 can be strengthened. Therefore, the reliability of the vibration actuator 1 against drop impact and the like can be improved.

[0056] Furthermore, since the spring 15 can be used to position the fixed portion 12, there is no need to perform fine processing on the base 11 in order to position the fixed portion 12. This makes it easier to manufacture the base 11, and therefore the vibration actuator 1.

[0057] Therefore, according to this embodiment, even if the vibration actuator 1 is made smaller, the ease of manufacture of the vibration actuator 1 can be ensured, and the reliability of the vibration actuator 1 against shocks caused by dropping and the like can be improved.

[0058] According to this embodiment, the vibration actuator 1 further includes a cylindrical case 10 having a hollow portion that is rectangular in plan view and penetrates in the vertical direction. The fixed portion 12 includes a first fixed portion 12-1 and a second fixed portion 12-2 that have a first magnet 12-1a and a second magnet 12-2a, respectively, that are identical in shape. The base 11 includes a first base 11-1 and a second base 11-2 that are identical in shape to which the first fixed portion 12-1 and the second fixed portion 12-2 are fixed, respectively. The spring 15 includes a first spring 15-1 and a second spring 15-2 that are identical in shape. In the first spring 15, a first inner portion 15-1a that is connected to the first base 11-1 has a first opening 15-1d into which the upper end portion 12-1c of the first fixed portion 12-1 is inserted. In the second spring 15-2, a second inner portion 15-2a connected to the second base 11-2 has a second opening 15-2d into which the lower end portion 12-2c of the second fixed portion 12-2 is inserted. The first base 11-1 and the second base 11-2 close the cylindrical case 10 from above and below with the first magnet 12-1a and the second magnet 12-2a facing each other, respectively.

[0059] According to the above configuration, the upper half including the first base 11-1, the first fixing portion 12-1, and the first spring 15-1 and the lower half including the second base 11-2, the second fixing portion 12-2, and the second spring 15-2 have the same shape. The upper and lower halves, which have the same shape, are assembled facing each other. Therefore, the components of the upper and lower halves can be standardized, and the number of components of the vibration actuator 1 can be substantially reduced.

[0060] An example of the implementation of the vibration actuator 1 will now be described.

[0061] Fig. 6 shows an example of an electrical device in which a vibration actuator equivalent to the vibration actuator 1 is mounted. Fig. 6 shows an example in which the vibration actuator 1 is mounted in a mobile terminal M.

[0062] The mobile terminal M is, for example, a mobile communication terminal such as a mobile phone, a smartphone, etc. The mobile terminal M can notify the user of an incoming call from, for example, an external communication device by vibration.

[0063] The mobile terminal M has a communication unit 101, a processing unit 102, a drive control unit 103, and a vibration actuator 104 which is the vibration actuator 1 serving as a drive unit. Note that a plurality of vibration actuators 104 may be implemented.

[0064] In the mobile terminal M, the vibration actuator 104 is preferably mounted so that, for example, the main surface (e.g., the operation surface) of the mobile terminal M and a surface perpendicular to the vibration direction of the vibration actuator 104, in this case the first base 11-1 and the second base 11-2, are parallel to each other.

[0065] The communication unit 101 is connected to an external communication device via wireless communication, receives a signal from the communication device, and outputs the signal to the processing unit 102. In the case of the mobile terminal M, the external communication device is, for example, a base station, and communication is performed in accordance with a mobile communication standard.

[0066] The processing unit 102 converts the input signal into a drive signal for driving the vibration actuator 104 using a conversion circuit unit (not shown), and outputs the drive signal to the drive control unit 103. In the mobile terminal M, the processing unit 102 generates a drive signal based on signals input from the communication unit 101 as well as signals input from various functional units (not shown, for example, an operation unit such as a touch panel).

[0067] The drive control unit 103 is connected to the vibration actuator 104, and is equipped with a circuit for driving the vibration actuator 104. The drive control unit 103 supplies a drive signal to the vibration actuator 104.

[0068] The vibration actuator 104 is driven in accordance with a drive signal from the drive control unit 103. Specifically, in the vibration actuator 104, the movable part 13 vibrates in a direction perpendicular to the main surface of the mobile terminal M.

[0069] Since vibrations in a direction perpendicular to the body surface are transmitted to the body surface of the user in contact with the mobile terminal M, it is possible to provide the user with a sufficiently sensible vibration.

[0070] Fig. 7 shows another example of an electrical device incorporating a vibration actuator equivalent to the vibration actuator 1. Fig. 7 shows an example in which the vibration actuator 1 is incorporated in a wearable terminal W.

[0071] The wearable terminal W, like the above-mentioned mobile terminal M, has a communication unit 101, a processing unit 102, a drive control unit 103, and a vibration actuator 104 which is the vibration actuator 1 serving as a drive unit. Note that a plurality of vibration actuators 104 may be implemented.

[0072] In the wearable terminal W, the vibration actuator 104 is preferably mounted so that, for example, the main surface of the wearable terminal W and the surface perpendicular to the vibration direction of the vibration actuator 104, here the first base 11-1 and the second base 11-2, are parallel to each other. If the wearable terminal W has a ring shape as shown in Fig. 7, for example, the surfaces of the first base 11-1 and the second base 11-2 should be arranged toward the center of the ring shape.

[0073] Since vibrations perpendicular to the body surface are transmitted to the body surface of the user in contact with the wearable terminal W, the user can be given a sufficiently bodily sensation of vibration.

[0074] In this way, the vibration actuator 1 (vibration actuator 104) is effective when mounted on a part of a portable or wearable electrical device that comes into contact with the user.

[0075] Although the embodiment of the present invention has been specifically described above, the present invention is not limited to the above-mentioned specific embodiment. Various modifications and changes can be made to the specific examples described in the above embodiment within the scope of the gist of the present invention described in the claims. [Industrial Applicability]

[0076] The vibration actuator according to the present invention is useful as a vibration generating source for, for example, notifying incoming calls in portable or wearable electrical devices such as mobile terminals. [Explanation of symbols]

[0077] 1. Vibration Actuator 10 Cylindrical case 10a side opening 11. Base 11-1 First Base 11-2 Second Base 12 Fixed part 12-1 First fixed part 12-1a First magnet 12-1b Magnet outer periphery 12-1c Upper end 12-2 Second fixed part 12-2a Second magnet 12-2b Magnet outer periphery 12-2c Lower end 13 Moving parts 13-1 Air core coil 13-2 Weight 13-2a Upper outer periphery 13-2b Lower outer periphery 13-2c Protrusion 14 Flexible PCB 14a Connection 14b Extension 15 Spring 15-1 First spring 15-1a First inner part 15-1b First outer part 15-1c First flexible part 15-1d First opening 15-1e First outer end 15-2 Second spring 15-2a Second inner part 15-2b Second outer part 15-2c Second flexible part 15-2d Second opening 15-2e Second outer end 5201 Communications Department 5202 Processing section 5203 Drive control unit M Mobile Device W Wearable device

Claims

1. a fixed portion including a magnet, the fixed portion having a thickness in a vertical direction and fixed to a base; a movable part that is disposed around the fixed part, is supported by a spring so as to be capable of vibrating in the vertical direction, includes a coil, and vibrates in the vertical direction by a driving force generated by an interaction between the coil and the magnet when a current is applied, the spring has a frustum shape, an outer portion of the spring is connected to an outer periphery of the movable portion, an inner portion of the spring is connected to the base, and the inner portion has an opening into which an end of the fixed portion in the up-down direction is inserted. Vibration actuator.

2. The fixing portion has a rectangular shape in a plan view, and the opening has a rectangular shape in a plan view corresponding to the rectangular shape of the fixing portion in a plan view.

2. The vibration actuator according to claim 1.

3. the movable portion has a rectangular shape in a plan view corresponding to the rectangular shape in a plan view of the fixed portion, The spring has two flexible parts each having a spiral shape extending from the inner part to the outer part, and an outer end of each of the two flexible parts is connected to two diagonally opposite corners of the outer periphery of the movable part. The vibration actuator according to claim 2 .

4. The springs include a first spring and a second spring having the same shape, the outer end portions of the two flexible portions of the first spring are connected to two diagonally opposite corners of an upper outer periphery of the movable portion, the outer end portions of the two flexible portions of the second spring are connected to two corner portions on a diagonal line of a lower outer periphery, the corner portions being in a positional relationship intersecting the diagonal line of the upper outer periphery of the movable portion; The vibration actuator according to claim 3 .

5. The device further includes a cylindrical case having a hollow portion that is rectangular in plan view and penetrates the device in the vertical direction, the fixed portion includes a first fixed portion and a second fixed portion having a first magnet and a second magnet, respectively, of the same shape; the base includes a first base and a second base having the same shape to which the first fixing portion and the second fixing portion are respectively fixed, The springs include a first spring and a second spring having the same shape, In the first spring, a first inner portion connected to the first base has an opening into which an upper end portion of the first fixed portion is inserted, In the second spring, a second inner portion connected to the second base has an opening into which a lower end portion of the second fixing portion is inserted, the first base and the second base close the cylindrical case from above and below with the first magnet and the second magnet facing each other, 5. A vibration actuator according to claim 1 or 4.

6. A portable or wearable electrical device, 13. An electrical device incorporating the vibration actuator according to claim 1.

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