Vibration actuator

Abstract

To provide a vibration actuator which can protect a coil despite having a small and simple structure.SOLUTION: A vibration actuator 10 includes: a case 12 formed in a cylindrical form; a movable element 14 which is housed in the case 12 and generates vibration by a yoke 22 and a magnet 24 moving relative to a coil 44; and a leaf spring 16 which is disposed spaced apart from the movable element 14 and connected to the movable element 14 by a shaft 30.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vibration actuator. [Background technology]

[0002] Patent Document 1 discloses a vibration actuator provided with upper and lower leaf springs. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6750825 Summary of the Invention [Problem to be solved by the invention]

[0004] Recently, there has been an increasing demand for small and simple vibration actuators, and structures with a leaf spring on only one side have been considered. However, there is a possibility that the free end side where the leaf spring is not provided may move in the radial direction and the mover may come into contact with the coil.

[0005] An object of the present invention is to provide a vibration actuator that can protect a coil even if it is small and has a simple structure. [Means for solving the problem]

[0006] The vibration actuator of the first aspect comprises a cylindrically shaped case, a movable element housed in the case and generating vibrations by relative movement of a yoke and a magnet with respect to a coil, and a leaf spring arranged at a distance from the movable element and connected to the movable element by a shaft.

[0007] In the above aspect, the movable element is housed in a cylindrically formed case, and the movable element generates vibrations by the relative movement of the yoke and magnet with respect to the coil. The movable element and the leaf spring are connected by a shaft. This allows the vibrations generated by the movable element to be transmitted to the leaf spring, causing the vibration target to vibrate. Here, the leaf spring is disposed at a distance from the movable element. This causes the center of gravity of the movable element in the case to move toward the other end, thereby suppressing the occurrence of rolling, in which the movable element swings radially, and suppressing contact between the movable element and the coil.

[0008] A vibration actuator according to a second aspect is the first aspect, wherein the yoke is formed into a cylindrical shape with a bottom, the magnet is fixed inside, and a spacer is provided between the yoke and the leaf spring.

[0009] In the above embodiment, the magnet is fixed to the inside of the cylindrical yoke with a bottom. Also, a spacer is provided between the yoke and the leaf spring. This allows the distance between the leaf spring and the mover to be adjusted simply by changing the height of the spacer.

[0010] A vibration actuator according to a third aspect is the second aspect, wherein the spacer is formed so that the other end connected to the leaf spring has a smaller diameter than the one end connected to the yoke.

[0011] In the above aspect, since the spacer is formed with a smaller diameter at the other end than at the other end, a wide vibration region of the leaf spring can be ensured, and vibration performance can be ensured even in a small size.

[0012] A vibration actuator according to a fourth aspect is the first aspect, wherein the shaft is attached with the yoke, the magnet, and the spacer inserted therethrough.

[0013] In the above embodiment, the yoke, magnet, and spacer are attached to the shaft in a state in which they are inserted therethrough, which makes it easy to position these components.

[0014] A vibration actuator according to a fifth aspect is the second aspect, wherein the side wall portion of the yoke is disposed between the case and the coil, and the dimension between the side wall portion and the case is smaller than the dimension between the side wall portion and the coil.

[0015] In the above-described embodiment, the dimension between the side wall portion of the yoke and the case is smaller than the dimension between the side wall portion and the coil, so that when the yoke oscillates within the case, it comes into contact with the case before the coil, thereby preventing the yoke from coming into contact with the coil.

[0016] A sixth aspect of the present invention relates to the vibration actuator of the fifth aspect, wherein a tip of the side wall portion is located on one end side of a pole piece attached to the magnet.

[0017] In the above embodiment, since the tip of the side wall portion of the yoke is located closer to one end than the pole piece, the yoke comes into contact with the case before the coil during rolling.

[0018] A vibration actuator according to a seventh aspect is the vibration actuator of the first aspect, further comprising a vibration suppressing section that limits the amplitude of the mover from exceeding a predetermined amplitude.

[0019] In the above-described embodiment, the case is provided with a stopper, which makes it possible to suppress excessive vibration of the mover when the case is dropped, for example. Effect of the Invention

[0020] According to the vibration actuator of the present invention, the coil can be protected even if it has a small and simple structure. [Brief description of the drawings]

[0021] [Figure 1] 1 is a cross-sectional view of a vibration actuator according to an embodiment, as viewed from a radial direction. [Diagram 2] 2 is a cross-sectional view showing a state cut along line 2-2 in FIG. 1. [Diagram 3] FIG. 2 is an enlarged view of a main part of FIG. 1. [Figure 4] 13 is a cross-sectional view of a vibration actuator according to a modified example, viewed from a radial direction. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] A vibration actuator 10 according to an embodiment will be described with reference to the drawings. FIG. 1 is a cross-sectional view of the vibration actuator 10 according to an embodiment as viewed from the radial direction. As shown in FIG. 1, the vibration actuator 10 includes a cylindrical case 12, a mover 14, a leaf spring 16, an upper cover 18, and a lower cover 20. In the following description, for convenience, one side of the central axis of the vibration actuator 10 will be referred to as one axial side (upper side), and the other side of the central axis will be referred to as the other axial side (lower side). In addition, in a direction perpendicular to the central axis, the side closer to the central axis will be referred to as the radial inner side, and the side away from the central axis will be referred to as the radial outer side.

[0023] Although the case 12 of the present embodiment is formed in a cylindrical shape, the present invention is not limited thereto and may be formed in a rectangular tube shape. Moreover, the case 12 of the present embodiment is made of resin, for example, but is not limited thereto and may be made of metal.

[0024] One axial end of the case 12 is open and is closed by an upper lid 18. The other axial end of the case 12 is open and is closed by a lower lid 20. The upper lid 18 and the lower lid 20 will be described in detail later.

[0025] A mover 14 is disposed inside the case 12. The mover 14 includes a yoke 22, a magnet 24, and a pole piece 26, which are housed in the case 12.

[0026] The yoke 22 is formed of a cylindrical soft magnetic material having a bottom on one axial side, and includes a substantially cylindrical side wall 22A and a bottom wall 22B. Therefore, as shown in FIG. 1, the cross-sectional shape of the yoke 22 viewed from the radial direction is a substantially U-shape with the other axial side open. The shaft 30 penetrates through the center of the bottom wall 22B of the yoke 22. Details of the shaft 30 will be described later.

[0027] A magnet 24 is fixed to the inside of the yoke 22. Specifically, the magnet 24 is formed in a generally cylindrical shape with a smaller diameter than the yoke 22, and is disposed inside the side wall portion 22A of the yoke 22. The upper end portion of the magnet 24 is fixed to the lower surface of the bottom wall portion 22B of the yoke 22. Furthermore, a through hole penetrating vertically is formed in the radial center portion of the magnet 24, and the shaft 30 is inserted through the through hole.

[0028] A pole piece 26 is disposed below the magnet 24. The pole piece 26 is formed in a substantially circular plate shape from a soft magnetic material, and the upper surface of the pole piece 26 is fixed to the lower surface of the magnet 24. A shaft 30 passes through the radial center portion of the pole piece 26.

[0029] Here, the pole piece is located above the lower end (tip) of the side wall portion 22A of the yoke 22. In other words, the tip of the side wall portion 22A of the yoke 22 is located below the pole piece (one end side).

[0030] The leaf spring 16 is provided above the mover 14. The leaf spring 16 is made of a thin metal plate, and is attached to the mover 14 via a spacer 28.

[0031] Fig. 2 is a cross-sectional view taken along line 2-2 in Fig. 1. As shown in Fig. 2, the leaf spring 16 is formed in a substantially circular shape when viewed in the axial direction. Furthermore, since a plurality of substantially arc-shaped grooves 16A are formed in the leaf spring 16, the leaf spring 16 is formed in a shape including a plurality of arc-shaped arms extending from the center to the outer periphery when viewed in the axial direction.

[0032] Three insertion holes 16B are formed in the outer peripheral end of the leaf spring 16. The insertion holes 16B are formed at equal intervals around the central axis, and are inserted through mounting pins 50 formed in the case 12. The mounting pins 50 have a smaller diameter than the insertion holes 16B and protrude upward from the upper end surface of the case 12. The mounting pins 50 are inserted through the insertion holes 16B of the leaf spring 16, thereby preventing the leaf spring 16 from rotating.

[0033] A substantially rectangular center hole 16C is formed in the radial center of the leaf spring 16, and an upper end 30A of a shaft 30 is fitted into the center hole 16C.

[0034] 1, the spacer 28 is provided between the yoke 22 and the leaf spring 16, and is formed to have a smaller diameter than the mover 14. Specifically, the spacer 28 in this embodiment is configured to include a small diameter portion 28A and a large diameter portion 28B.

[0035] The small diameter portion 28A is formed in a substantially cylindrical shape, and a lower end portion of the small diameter portion 28A is fixed to an upper surface of the bottom wall portion 22B of the yoke 22. In addition, an upper end portion of the small diameter portion 28A is fixed to a lower surface of the leaf spring 16.

[0036] The large diameter portion 28B is a substantially annular portion provided on the outer periphery of the lower end of the small diameter portion 28A, and the lower end of the large diameter portion 28B is fixed to the upper surface of the bottom wall portion 22B of the yoke 22. Here, the large diameter portion 28B may be formed integrally with the small diameter portion 28A, or may be formed separately. In this manner, the spacer 28 is formed so that the upper end (the other end) connected to the leaf spring 16 has a smaller diameter than the lower end (one end) connected to the yoke 22. The leaf spring 16 is disposed at a distance from the mover 14 by the spacer 28, and is connected to the mover 14 by the spacer 28 and the shaft 30.

[0037] The shaft 30 extends in the axial direction, and the upper end 30A of the shaft 30 is fitted into the central hole 16C of the leaf spring 16 as described above. The shaft 30 also passes through the spacer 28, the yoke 22, and the magnet 24, and the lower end 30B of the shaft 30 is fitted into the pole piece 26.

[0038] A stopper 17 is provided on the upper surface of the leaf spring 16. The stopper 17 is formed in a substantially circular plate shape with an outer shape similar to that of the spacer 28, and the shaft 30 is inserted into the radial center portion of the stopper 17. This results in a structure in which the leaf spring 16 is sandwiched between the spacer 28 and the stopper 17. In other words, the stopper 17 functions to prevent the shaft 30 from coming off.

[0039] An upper lid 18 is provided above the leaf spring 16. The upper lid 18 is formed of a cylindrical resin member with one axial side serving as the bottom, and the opening at the upper end of the case 12 is closed by the upper lid 18. The leaf spring 16 is sandwiched between a side wall portion 18A of the upper lid 18 and the upper end surface of the case 12.

[0040] An insertion hole 18C is formed in the radial center of the bottom wall portion 18B of the top lid 18. The insertion hole 18C is formed with a diameter larger than that of the shaft 30, and prevents the upper end 30A of the shaft 30 from interfering with the top lid 18 even if the mover 14 moves excessively upward. Furthermore, if the mover 14 moves excessively upward, the stopper 17 abuts against the lower surface of the bottom wall portion 18B of the top lid 18, thereby restricting the mover 14 from vibrating more than a predetermined amount. That is, the stopper 17 also functions as a vibration suppressing portion.

[0041] On the other hand, a bottom lid 20 is provided below the movable element 14. The bottom lid 20 is formed in a substantially cylindrical shape and includes a lid main body portion 40 and a cylindrical portion 42. The bottom lid 20 closes the opening on the bottom end side (the other end side) of the case 12.

[0042] The lid main body 40 has an annular flange portion 40A. The flange portion 40A extends radially outward from the inner surface of the case 12 and contacts the lower end surface of the case 12. In addition, a locking claw portion 40B is provided on the lid main body 40 above the flange portion 40A.

[0043] The locking claw portion 40B protrudes radially outward from the general surface of the lid main body 40 and is pressed against the inner surface of the case 12. In addition, the locking claw portion 40B is locked to the lower end of the case 12, preventing the lower lid 20 from coming off.

[0044] An upper wall portion 40C is formed at the upper end of the lid main body portion 40, and an insertion hole 40D is formed in the radial center portion of the upper wall portion 40C. The insertion hole 40D is formed with a larger diameter than the shaft 30, and prevents the lower end 30B of the shaft 30 from interfering with the lower lid 20.

[0045] A cylindrical portion 42 protrudes upward from the upper end of the lid main body 40. The cylindrical portion 42 is formed in a cylindrical shape with a smaller diameter than the lid main body 40, and the lower end of the magnet 24 and the pole piece 26 fit into the inner periphery of the cylindrical portion 42.

[0046] Here, a recess 42A is formed on the outer circumferential surface of the cylindrical portion 42. The recess 42A is formed around the entire outer circumferential surface of the cylindrical portion 42, and a coil 44 is wound around this recess 42A. The side wall portion 22A of the yoke 22 is disposed on the radial outside of the coil 44, and the magnet 24 and the pole piece 26 are disposed on the radial inside of the coil 44.

[0047] In this way, a magnetic circuit is formed including the yoke 22, magnet 24, and pole piece 26 that constitute the mover 14, and a strong magnetic field is generated in the gap between the pole piece 26 and the yoke 22. Since the coil 44 is disposed in the magnetic circuit, a force along the axial direction acts on the mover 14 when electricity is applied to the coil 44. In other words, the mover 14 generates vibration as the yoke 22 and magnet 24 move relative to the coil 44.

[0048] Here, FIG. 1 illustrates a state in which the yoke 22 is in the initial position. When an axial force is applied to the yoke 22, the yoke 22 is displaced in the axial direction against the biasing force of the leaf spring 16. When the external force input to the yoke 22 is removed, the biasing force of the leaf spring 16 displaces the yoke 22 toward the initial position of FIG. 1. This is repeated, causing the mover 14 to vibrate up and down, vibrating the vibration target to which the case 12 is attached. Note that the vibration target referred to here is not particularly limited as long as it generates vibration. In this embodiment, as an example, the vibration actuator 10 is mounted on a controller used for video games, etc., but it may also be mounted on a haptic device, a mobile phone, a tablet terminal, a massage machine, etc.

[0049] When a strong impact is applied to the mover 14, the stopper 17 abuts against the lower surface of the bottom wall portion 18B of the upper cover 18 as described above, thereby restricting the mover 14 from vibrating more than a predetermined amount. Similarly, the lower end of the yoke 22 abuts against the upper end of the cover body portion 40 of the lower cover 20, thereby restricting the mover 14 from vibrating more than a predetermined amount. Therefore, the upper surface of the cover body portion 40 functions as a vibration suppressing portion. In this embodiment, the tip of the side wall portion 22A of the yoke 22 is located below the pole piece 26, but a structure in which the pole piece 26 is located below the yoke 22 may be adopted. In this case, the pole piece 26 abuts against the upper surface of the cover body portion 40 before the yoke 22, thereby restricting the mover 14 from vibrating more than a predetermined amount, as in this embodiment.

[0050] Fig. 3 is an enlarged view of the main part of Fig. 1. As shown in Fig. 3, the side wall portion 22A of the yoke 22 is disposed between the case 12 and the coil 44. In this embodiment, as an example, the dimension D1 between the side wall portion 22A and the case 12 is set to be smaller than the dimension D2 between the side wall portion 22A and the coil 44.

[0051] (action) Next, the operation of this embodiment will be described.

[0052] 1, in the vibration actuator 10 according to this embodiment, a mover 14 is housed in a cylindrical case 12, and the mover 14 generates vibrations as a result of the relative movement of a yoke 22 and a magnet 24 with respect to a coil 44. In addition, a leaf spring 16 is attached to one end side of the mover 14. As a result, the vibrations generated by the mover 14 are transmitted to the leaf spring 16, and the object to which the vibration actuator 10 is attached can be vibrated.

[0053] Here, the leaf spring 16 is attached to the mover 14 via a spacer 28 that has a smaller diameter than the mover 14. This ensures a wider vibration region for the leaf spring 16 compared to a structure in which the leaf spring 16 is directly attached to the mover 14, and ensures vibration excitation performance even in a small size. In other words, the vibration actuator 10 of this embodiment can generate vibration with a small and simple structure.

[0054] In this embodiment, the leaf spring 16 is sandwiched between the top lid 18 and the case 12, and the coil 44 is provided on the bottom lid 20 of the case 12. This eliminates the need to provide separate dedicated parts for mounting the leaf spring 16 and the coil 44, simplifying the structure.

[0055] Furthermore, in this embodiment, the coil 44 is wound around a recess 42A formed on the outer surface of the cylindrical portion 42. This allows the cylindrical portion 42 constituting the lower cover 20 to function as a bobbin, making it unnecessary to provide a separate bobbin.

[0056] Furthermore, in this embodiment, the leaf spring 16 is attached to one end of the shaft 30, and the yoke 22, magnet 24, pole piece 26 and spacer 28 are attached to the other end of the shaft 30. This makes it possible to easily position the vibration actuator 10 using the shaft 30, even if it is small in size.

[0057] In this embodiment, the leaf spring 16 is disposed at a distance from the mover 14. This causes the center of gravity of the mover 14 in the case 12 to move downward (toward the other end), thereby making it possible to suppress rolling, in which the mover 14 swings radially, and to suppress contact between the mover 14 and the coil 44.

[0058] Furthermore, in this embodiment, a magnet 24 is fixed inside the cylindrical yoke 22 with a bottom, and a spacer 28 is provided between the yoke 22 and the leaf spring 16. This makes it possible to adjust the distance between the leaf spring 16 and the mover 14 simply by changing the height of the spacer 28.

[0059] Furthermore, in this embodiment, the spacer 28 is formed with a smaller diameter at the upper end (other end) than at the lower end (one end), so that a wide vibration area of ​​the leaf spring 16 can be secured, and vibration performance can be secured even in a small size.

[0060] In addition, in this embodiment, as shown in FIG. 3, the dimension D1 between the side wall portion 22A of the yoke 22 and the case 12 is smaller than the dimension D2 between the side wall portion 22A and the coil 44. Therefore, when the yoke 22 oscillates within the case 12, the yoke 22 comes into contact with the case 12 before the coil 44, thereby preventing the yoke 22 from coming into contact with the coil 44.

[0061] Furthermore, since the tip of the side wall portion 22A of the yoke 22 is located below (on one end side of) the pole piece 26, the yoke 22 comes into contact with the case 12 before the coil 44 does during rolling.

[0062] Furthermore, the provision of the stopper 17 makes it possible to suppress excessive vibration of the mover 14 when it is dropped, etc. In this way, with the vibration actuator 10 of this embodiment, the coil 44 can be protected even though it has a small and simple structure.

[0063] In the above embodiment, the small diameter portion 28A of the spacer 28 has a substantially rectangular shape in side view, but is not limited to this, and a modified structure shown in FIG. 4 may be adopted.

[0064] (Modification) Fig. 4 is a cross-sectional view of a vibration actuator 60 according to a modified example, viewed from the radial direction. As shown in Fig. 4, the vibration actuator 60 according to this modified example has the same configuration as the embodiment, except for the spacer 62 and the stopper 64.

[0065] The spacer 62 is provided between the yoke 22 and the leaf spring 16, and is formed to have a smaller diameter than the mover 14. The spacer 62 is configured to include a small diameter portion 62A and a large diameter portion 62B.

[0066] The small diameter portion 62A is formed in a generally truncated cone shape with a diameter that decreases toward the top, and a lower end portion of the small diameter portion 62A is fixed to an upper surface of the bottom wall portion 22B of the yoke 22. In addition, an upper end portion of the small diameter portion 62A is fixed to a lower surface of the leaf spring 16.

[0067] The large diameter portion 62B is a substantially annular portion provided on the outer periphery of the lower end of the small diameter portion 62A, and the lower end of the large diameter portion 62B is fixed to the upper surface of the bottom wall portion 22B of the yoke 22. Here, the large diameter portion 62B may be formed integrally with the small diameter portion 62A or may be formed separately. Also, the large diameter portion 62B does not necessarily have to be provided.

[0068] A stopper 64 is provided on the upper surface of the leaf spring 16. The stopper 64 is formed in a substantially circular plate shape with an outer shape roughly the same as the upper end of the spacer 62, and the shaft 30 is inserted through the radial center portion of the stopper 64. For this reason, the leaf spring 16 is sandwiched between the spacer 62 and the stopper 64.

[0069] By making the upper end of the spacer 62 have a small diameter as in this modified example, the vibration region of the leaf spring 16 can be secured to be wide.

[0070] 〔supplementary explanation〕 The vibration actuators 10 and 60 according to the embodiment and the modified examples have been described above, but it goes without saying that the present invention can be embodied in various forms without departing from the spirit and scope of the present invention. For example, in the above embodiment, the spacer 28 is provided as shown in Fig. 1, but the present invention is not limited to this, and the spacer 28 may not be provided. Even in this case, the same effect can be achieved as long as the mover 14 is disposed away from the leaf spring 16.

[0071] In addition, in this embodiment, an internal magnet type magnetic circuit is configured in which the magnet 24 is disposed on the inner circumferential side of the coil 44, but the present invention is not limited to this, and an external magnet type magnetic circuit may also be adopted.

[0072] Furthermore, in the above embodiment and modified example, the magnetic circuit is formed including the yoke 22, the magnet 24, and the pole piece 26, but this is not limiting, and a structure further including a second yoke in addition to the yoke 22 may be adopted. For example, the second yoke may be provided between the magnet 24 and the yoke 22. In this case, the yoke 22 and the second yoke may be formed integrally. Also, for example, the second yoke may be provided between the magnet 24 and the pole piece 26. In this case, the pole piece 26 and the second yoke may be formed integrally.

[0073] Furthermore, in the above embodiment and modified examples, an adhesive may be interposed between the components that make up the magnetic circuit.

[0074] In the above embodiment and modified example, the upper end 30A of the shaft 30 is fitted into the central hole 16C of the leaf spring 16, and the lower end 30B of the shaft 30 is fitted into the pole piece 26, but the present invention is not limited to this, and the upper and lower ends of the shaft 30 may be fixed by a method other than fitting. For example, the upper and lower ends of the shaft 30 may be fixed by crimping. [Explanation of symbols]

[0075] 10. Vibration Actuator 12 cases 14 Mover 16 Leaf spring 17 Stopper 18 Top lid 20 Lower lid 22 York 24 Magnet 26 Pole Piece 28 Spacer 30 Shaft (vibration suppression part) 40 Lid body part (vibration suppression part) 44 Coil 60 Vibration Actuator

Claims

1. A cylindrically formed case; a mover that is housed in the case and generates vibration when a yoke and a magnet move relative to a coil; a leaf spring disposed on one end side of the mover at a distance from the mover and connected to the mover by a shaft; A vibration actuator having

2. The yoke is formed in a cylindrical shape with a bottom, and the magnet is fixed inside the yoke. The vibration actuator according to claim 1 , further comprising a spacer provided between the yoke and the leaf spring.

3. 3. The vibration actuator according to claim 2, wherein the spacer is formed so that the diameter of the other end connected to the leaf spring is smaller than the diameter of the other end connected to the yoke.

4. 2. The vibration actuator according to claim 1, wherein the shaft is attached with the yoke, the magnet, and the spacer inserted therethrough.

5. 3. The vibration actuator according to claim 2, wherein the side wall portion of the yoke is disposed between the case and the coil, and the dimension between the side wall portion and the case is smaller than the dimension between the side wall portion and the coil.

6. 6. The vibration actuator according to claim 5, wherein a tip of the side wall portion is located on one end side of a pole piece attached to the magnet.

7. 2. The vibration actuator according to claim 1, further comprising a vibration suppressing portion that limits the amplitude of the mover from exceeding a predetermined amplitude.

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