Actuator unit and musical instrument

Abstract

The actuator unit includes an actuator that vibrates a soundboard of a musical instrument, and a movement allowing portion that connects a frame of the musical instrument and the actuator so that the actuator can move within a predetermined range relative to the frame.

Description

Technical Field

[0001] The present invention relates to an actuator unit and a musical instrument.

[0002] This application claims priority based on Japanese Patent Application No. 2019-190959, filed on October 18, 2019, and all the disclosed contents are incorporated herein by reference. Background Art

[0003] Conventionally, various musical instruments such as keyboard instruments are equipped with actuators that vibrate a soundboard (in a predetermined direction) based on an input audio signal to produce sound.

[0004] Patent document 1 discloses a structure in which a soundboard and a vibrating body of an actuator are connected by a connecting body. In the structure of patent document 1, a plurality of joints are provided for tilting the connecting body relative to the thickness direction of the soundboard and the vibration direction of the vibrating body. By providing the joints in the connecting body, even if the relative position and orientation between the soundboard and the actuator change due to the aging of the soundboard due to the influence of temperature, humidity, etc., the soundboard can be properly vibrated by the actuator.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-114457 Summary of the invention

[0006] However, if the structure (connection structure) for connecting the soundboard and the vibrating body of the actuator includes a joint in addition to the connecting body, the connection structure that vibrates together with the vibrating body becomes complicated. Therefore, it becomes difficult to make the soundboard vibrate at a high frequency, and the playback characteristics of the high frequency range will deteriorate. As a result, the problem of reduced quality of audio playback through the actuator and the soundboard occurs.

[0007] The present invention has been made in view of the above circumstances. One example of an object of the present invention is to provide an actuator unit and a musical instrument that can achieve high-quality audio reproduction by simplifying the connection structure between a soundboard and a vibrating body of an actuator.

[0008] One embodiment of the present invention is an actuator unit having: an actuator that vibrates a soundboard of a musical instrument; and a movement allowing portion that connects a frame of the musical instrument and the actuator so that the actuator can move within a specified range relative to the frame.

[0009] Another aspect of the present invention is a musical instrument including the above-mentioned actuator unit.

[0010] Effects of the Invention

[0011] According to the embodiment of the present invention, high-quality audio reproduction can be achieved by simplifying the connection structure between the soundboard and the vibrating body of the actuator. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of a piano on which the actuator unit according to the first embodiment of the present invention is mounted, as viewed from below.

[0013] Figure 2 It is a cross-sectional view showing a state where the actuator unit according to the first embodiment of the present invention is mounted on a piano.

[0014] Figure 3 It is schematically shown in Figure 2 A diagram illustrating the effect of a spherical plain bearing included in an actuator unit.

[0015] Figure 4 It is a cross-sectional view showing a state where an actuator unit according to a second embodiment of the present invention is mounted on a piano.

[0016] Figure 5 It is a cross-sectional view showing a state where an actuator unit according to a third embodiment of the present invention is mounted on a piano. DETAILED DESCRIPTION

[0017] [First embodiment]

[0018] Below, refer to Figures 1 to 3 A first embodiment of the present invention will be described.

[0019] Figure 1 A grand piano 100 (hereinafter, also simply referred to as piano 100 ) which is one type of keyboard musical instrument is shown as a musical instrument to which the actuator unit 1 according to the first embodiment of the present invention is applied. Figure 1 The Z-axis direction of 1 represents the up-down direction of the piano 100. The piano 100 has a frame 110 and a soundboard 120. Figure 1 Thus, if the grand piano 100 is viewed from the bottom, the plurality of straight struts 111 and the soundboard 120 constituting the frame 110 can be seen. Figure 2 As shown, a plurality of straight pillars 111 are located below the sound board 120 (in the negative direction of the Z axis) and are spaced apart from each other.

[0020] like Figure 2 As shown, the actuator unit 1 according to this embodiment connects the frame 110 and the soundboard 120 of the piano 100 to vibrate the soundboard 120. The actuator unit 1 includes an actuator 2 for vibrating the soundboard 120 and a movement allowance 3 that allows the actuator 2 to move within a predetermined range relative to the frame 110.

[0021] The actuator 2 includes a main body 11 and a vibrating body 12 which vibrates in a predetermined direction ( Figure 1 and a vibration damper portion 13, which connects the vibrating body 12 to the main body 11.

[0022] The main body 11 has a magnetic circuit forming portion 14 that forms a magnetic circuit. The magnetic circuit forming portion 14 has a top plate 15, a yoke 16, and a magnet 17. The top plate 15 and the yoke 16 are made of soft magnetic materials such as soft iron. The top plate 15 is formed in the shape of a circular ring. The yoke 16 has a circular plate portion 16A in the shape of a circular plate, and a cylindrical portion 16B protruding from the center of the circular plate portion 16A. The yoke 16 has a through hole 16C. The through hole 16C connects the circular plate portion 16A and the cylindrical portion 16B along their axis A1 direction ( Figure 1 The yoke 16 is configured so that the circular plate portion 16A is opposite to the top plate 15 in the direction of the axis A1, and the front end of the cylindrical portion 16B enters the inner side of the top plate 15. The magnet 17 is a permanent magnet formed in an annular shape. The magnet 17 is configured so that the cylindrical portion 16B is inserted through and is sandwiched between the top plate 15 and the circular plate portion 16A.

[0023] By providing the magnetic path forming portion 14 configured as described above, a magnetic field is generated in a gap between the inner periphery of the top plate 15 and the outer periphery of the front end portion of the cylindrical portion 16B.

[0024] The vibrating body 12 includes a cylindrical portion 18 and a cover portion 19. The cylindrical portion 18 is inserted into a gap between the inner periphery of the top plate 15 and the outer periphery of the cylindrical portion 16B of the yoke 16. The cover portion 19 closes one opening of the cylindrical portion 18.

[0025] The cylindrical portion 18 includes a bobbin (not shown) and a voice coil (not shown) wound around the bobbin. The vibrating body 12 is located near the first end of the main body 11 where the top plate 15 is located in the direction of the axis A1 of the magnetic path forming portion 14 .

[0026] The damper portion 13 holds the cylindrical portion 18 of the vibrating body 12 in the gap between the inner periphery of the top plate 15 and the outer periphery of the cylindrical portion 16B of the yoke 16. The damper portion 13 is formed to be elastically deformable. The damper portion 13 holds the cylindrical portion 18 at a predetermined position of the magnetic path forming portion 14 by its elastic force. In addition, when the cylindrical portion 18 deviates from the above-mentioned predetermined position, the damper portion 13 causes the cylindrical portion 18 to tend to the above-mentioned predetermined position by the elastic force of the damper portion 13 itself.

[0027] In the actuator 2, a current corresponding to the audio signal flows in the voice coil of the vibrating body 12, whereby the vibrating body 12 vibrates in the direction of the axis A1 of the main body 11. In addition, the audio signal is generated, for example, as a drive signal for driving the vibrating body 12 in a control device (not shown) based on audio data stored in a storage unit (not shown).

[0028] The actuator 2 of the present embodiment has a connection portion 20 that connects the vibrating body 12 to the soundboard 120. The specific structure of the connection portion 20 may be arbitrary. The connection portion 20 of the present embodiment includes a rod-shaped portion 21 and a mounting plate portion 22. The rod-shaped portion 21 extends from the vibrating body 12 along the vibration direction (axis A1 direction) of the vibrating body 12. The mounting plate portion 22 is provided at the front end portion of the rod-shaped portion 21 and is fixed to the soundboard 120. The base end portion of the rod-shaped portion 21 is fixed to the cover portion 19 of the vibrating body 12.

[0029] The movement allowing portion 3 is provided to connect the frame 110 and the actuator 2. The movement allowing portion 3 of the present embodiment includes a plane sliding bearing 30 and a spherical sliding bearing (spherical plain bearing) 40.

[0030] The plane sliding bearing 30 includes first and second flat surface members (a pair of flat surface members) 31 and 32 having flat surfaces 31a and 32a. The flat surfaces 31a and 32a are movable relative to each other in a state of being in surface contact with each other.

[0031] The plane sliding bearing 30 includes a movement limiting portion 35 (first movement limiting portion 35) that limits the range of relative movement of the first and second flat surface members 31 and 32. The specific structure of the first movement limiting portion 35 can be arbitrary. The first movement limiting portion 35 of the present embodiment is a peripheral wall portion 31B protruding from the peripheral edge of the flat surface 31a of the first flat surface member 31. The peripheral wall portion 31B is formed in an annular shape and surrounds the second flat surface member 32 that is in surface contact with the flat surface 31a of the first flat surface member 31. As a result, it is possible to prevent the second flat surface member 32 from protruding from the edge of the flat surface 31a of the first flat surface member 31. In addition, the peripheral wall portion 31B is not limited to being formed on the first flat surface member 31. For example, a peripheral wall portion can be formed on the second flat surface member 32, and the peripheral wall portion surrounds the first flat surface member 31, thereby preventing the first flat surface member 31 from protruding from the edge of the flat surface 32a of the second flat surface member 32.

[0032] By disposing the first and second flat surface members 31 and 32 as described above, the actuator 2 can be moved relative to the frame 110 in directions along the flat surfaces 31 a and 32 a of the first and second flat surface members 31 and 32 (X-axis direction and Y-axis direction).

[0033] The plane sliding bearing 30 is preferably arranged so that the first and second flat surface members 31 and 32 are aligned in the vertical direction (Z-axis direction).

[0034] The spherical sliding bearing 40 includes a first spherical component 41 having a spherical convex surface 41a and a second spherical component 42 having a spherical concave surface 42a. The spherical convex surface 41a and the spherical concave surface 42a have the same curvature radius, so that the spherical convex surface 41a and the spherical concave surface 42a are in surface contact. The spherical convex surface 41a and the spherical concave surface 42a can move relative to each other in a state of surface contact.

[0035] The spherical sliding bearing 40 includes a movement limiting portion 45 (second movement limiting portion 45) that limits the range of relative movement of the first and second spherical components 41 and 42. The specific structure of the second movement limiting portion 45 can be arbitrary. The second movement limiting portion 45 of the present embodiment is a peripheral wall portion 41B protruding from the peripheral edge of the spherical convex surface 41a of the first spherical component 41. The peripheral wall portion 41B is formed in an annular shape and surrounds the second spherical component 42 that is in surface contact with the spherical convex surface 41a of the first spherical component 41. As a result, it is possible to prevent the second spherical component 42 from protruding from the edge of the spherical convex surface 41a of the first spherical component 41. In addition, the peripheral wall portion 41B is not limited to being formed on the first spherical component 41. For example, a peripheral wall portion may be formed on the second spherical component 42, and the peripheral wall portion surrounds the first spherical component 41, thereby preventing the first spherical component 41 from protruding from the edge of the spherical concave surface 42a of the second spherical component 42.

[0036] In the present embodiment, the first spherical component 41 is located near the actuator 2, and the second spherical component 42 is located near the frame 110. Alternatively, the first spherical component 41 may be located near the frame 110, and the second spherical component 42 may be located near the actuator 2. As described above, by arranging the first and second spherical components 41 and 42, the actuator 2 can be rotated relative to the frame 110 around the center of curvature C1 of the spherical convex surface 41a and the spherical concave surface 42a.

[0037] The spherical sliding bearing 40 is preferably arranged such that the first and second spherical components 41 and 42 are arranged side by side in the vertical direction (Z-axis direction). In addition, it is more preferable to arrange the second spherical component 42 below the first spherical component 41 (on the negative side in the Z-axis direction).

[0038] The above-mentioned plane sliding bearing 30 and spherical sliding bearing 40 are arranged in the arrangement direction (Z-axis direction) of the first and second flat surface members 31 and 32 and the arrangement direction (Z-axis direction) of the first and second spherical surface members 41 and 42. In this embodiment, one of the first and second flat surface members 31 and 32 and one of the first and second spherical surface members 41 and 42 are formed integrally. Figure 2 In the example shown, the second flat surface member 32 and the second spherical surface member 42 are formed integrally, but they may be formed separately, for example.

[0039] The first and second flat surface members 31 and 32 constituting the movement allowing portion 3 are preferably made of a material that can slide easily on each other (a material with a small friction coefficient). Similarly, the first and second spherical surface members 41 and 42 are preferably made of a material that can slide easily on each other (a material with a small friction coefficient). For example, one of the first and second flat surface members 31 and 32 may be made of polyoxymethylene (POM) and the other may be made of ABS resin (the same also applies to the first and second spherical surface members 41 and 42). The first and second flat surface members 31 and 32 may be made of the same material or different materials. However, the material constituting the first and second flat surface members 31 and 32 is preferably selected in such a way that the friction coefficient of the first and second flat surface members 31 and 32 becomes small. Similarly, the material constituting the first and second spherical surface members 41 and 42 is preferably selected in such a way that the friction coefficient of the first and second spherical surface members 41 and 42 becomes small, and may be the same as or different from each other.

[0040] The movement-allowing portion 3 is fixed to the main body 11 of the actuator 2. The movement-allowing portion 3 of the present embodiment is arranged in the direction of the axis A1 of the actuator 2 (i.e., the vibration direction of the vibrating body 12) relative to the actuator 2. Specifically, the movement-allowing portion 3 is fixed to the second end portion of the main body 11 opposite to the first end portion of the main body 11 where the vibrating body 12 is located in the direction of the axis A1 of the actuator 2 in the main body 11. In the present embodiment, the first spherical component 41 constituting the movement-allowing portion 3 is fixed to the main body 11 of the actuator 2.

[0041] In a state where the movement allowing portion 3 is fixed to the actuator 2 , the center of curvature C1 of the spherical convex surface 41 a and the spherical concave surface 42 a is located on the axis A1 of the actuator 2 .

[0042] The actuator unit 1 is mounted on the piano 100 so as to connect the frame 110 and the soundboard 120 of the piano 100. In the present embodiment, the connecting portion 20 (particularly the mounting plate portion 22) of the actuator unit 1 is fixed to the soundboard 120. In addition, the movement allowing portion 3 of the actuator unit 1 is fixed to the frame 110. The movement allowing portion 3 may be fixed to a side plate of the frame 110, for example, but in the present embodiment, the movement allowing portion 3 is fixed to the side plate of the frame 110. Figure 1 , 2 A straight support column 111 is shown fixed to the frame 110 .

[0043] Specifically, if Figure 2As shown, the first flat surface member 31 of the movement allowing portion 3 is fixed to the straight support 111 via the intermediary member 5. The intermediary member 5 is fixed to the side surface of the straight support 111 (the surface extending in the Z-axis direction). The intermediary member 5 has a supporting plate portion 51 extending from the side surface of the straight support 111 in a direction orthogonal to the side surface of the straight support 111 (the negative direction of the X-axis). The first flat surface member 31 is fixed to the supporting plate portion 51 (the opposite surface of the supporting plate portion 51 facing the sound board 120). In this state, the first flat surface member 31, the second flat surface member 32 and the second spherical surface member 42 formed integrally, and the first spherical surface member 41 are arranged in this order from the supporting plate portion 51 to the upper direction (the positive direction of the Z-axis).

[0044] In the piano 100 equipped with the actuator unit 1, the vibration of the vibrating body 12 according to the audio signal is transmitted to the soundboard 120 via the connecting part 20, thereby vibrating the soundboard 120. The vibration of the soundboard 120 becomes a sound propagating in the air, thereby playing the audio.

[0045] In the piano 100 equipped with the actuator unit 1, the actuator 2 is movable relative to the frame 110 by the movement allowing portion 3. Therefore, even if the mounting position of the soundboard 120 where the actuator 2 is mounted changes with the aging of the soundboard 120, the direction and position of the actuator 2 can follow the change of the soundboard 120.

[0046] For example, when the mounting portion of the soundboard 120 is displaced in the direction along the surface of the soundboard 120 (X-axis direction, Y-axis direction), the first and second flat surface components 31 and 32 move relatively in the directions along their flat surfaces 31a and 32a (X-axis direction, Y-axis direction). As a result, the position of the actuator 2 can follow the displacement of the soundboard 120. That is, the movement allowing portion 3 has the degree of freedom of translation in two axes (X-axis and Y-axis). In addition, when the mounting portion of the soundboard 120 is displaced in the plate thickness direction (Z-axis direction) of the soundboard 120, the vibrating body 12 of the actuator 2 is displaced relative to the main body 11 in the vibration direction of the vibrating body 12 (Z-axis direction). That is, the actuator unit 1 has the degree of freedom of translation in three axes in total.

[0047] In addition, for example Figure 3 As shown, when the orientation of the mounting portion of the soundboard 120 changes, the first and second spherical components 41 and 42 move relative to each other while the spherical convex surface 41a and the spherical concave surface 42a are in surface contact. As a result, the orientation of the actuator 2 (particularly the orientation of the axis A1 of the vibrating body 12) can follow the change in the orientation of the soundboard 120. Figure 3In response to the change in the orientation of the soundboard 120 about the Y axis, the first spherical member 41 rotates relative to the second spherical member 42 about the Y axis, whereby the orientation of the actuator 2 follows the change in the orientation of the soundboard 120 .

[0048] Although not shown in the figure, in this embodiment, the first spherical component 41 rotates relative to the second spherical component 42 about the X-axis in accordance with the change in the orientation of the soundboard 120 about the X-axis, thereby enabling the orientation of the actuator 2 to follow the change in the orientation of the soundboard 120.

[0049] In addition, in the present embodiment, in accordance with the change in the orientation of the soundboard 120 with the Z-axis as the axis, the first and second spherical components 41 and 42 rotate relative to each other with the Z-axis as the axis, or the first and second flat surface components 31 and 32 rotate relative to each other with the Z-axis as the axis, thereby enabling the orientation of the actuator 2 to follow the change in the orientation of the soundboard 120.

[0050] As described above, the movement allowing unit 3 of the present embodiment has the degree of freedom of rotation about three axes.

[0051] As described above, according to the actuator unit 1 of the present embodiment, the movement allowing portion 3 is sandwiched between the frame 110 and the actuator 2. Therefore, even if the actuator unit 1 of the present embodiment does not have a joint portion as in the past in the connection structure that connects the vibrating body 12 of the actuator 2 and the soundboard 120 including the connection portion 20, etc., the orientation and position of the actuator 2 can follow the changes of the soundboard 120 based on the aging change. As a result, the connection structure that vibrates together with the vibrating body 12 can be simpler than before. As a result, the playback frequency band obtained by the actuator 2 and the soundboard 120 can be extended to a higher range. Therefore, audio playback under a wide frequency band can be performed, and high-quality audio playback can be achieved.

[0052] In addition, in the actuator unit 1 of the present embodiment, the actuator 2 can be linearly moved relative to the frame 110 by the plane sliding bearing 30. Therefore, even if the mounting portion of the soundboard 120 to which the actuator 2 is mounted is displaced in the direction along the surface of the soundboard 120 (the surface direction of the soundboard 120), the actuator 2 can follow the displacement in the surface direction of the soundboard 120 by the plane sliding bearing 30.

[0053] In the actuator unit 1 of the present embodiment, the actuator 2 can be rotatably moved relative to the frame 110 by the spherical sliding bearing 40. Thus, even if the orientation of the mounting portion of the soundboard 120 to which the actuator 2 is mounted changes, the orientation of the actuator 2 (particularly the orientation of the axis A1 of the vibrating body 12) can follow the change in the orientation of the soundboard 120 by the spherical sliding bearing 40.

[0054] In the actuator unit 1 of the present embodiment, one of the first and second flat surface members 31 and 32 is integrally formed with one of the first and second spherical surface members 41 and 42. Therefore, the number of components constituting the movement allowing portion 3 can be reduced. Thus, the actuator unit 1 including the movement allowing portion 3 can be easily assembled.

[0055] In the actuator unit 1 of the present embodiment, the movement permission portion 3 is arranged in the direction of the axis A1 (vibration direction) of the actuator 2 relative to the actuator 2. In this case, in a state where the actuator unit 1 is arranged so that the axis A1 of the actuator 2 (vibration direction of the vibrating body 12) is oriented in the vertical direction, the first and second flat surface members 31 and 32 that slide on each other are arranged in the vertical direction. Similarly, in this state, the first and second spherical surface members 41 and 42 that slide on each other are arranged in the vertical direction. Therefore, it is possible to suppress the first and second flat surface members 31 and 32 from moving relative to each other due to gravity. Similarly, it is possible to suppress the first and second spherical surface members 41 and 42 from moving relative to each other due to gravity. That is, the movement permission portion 3 is not easily affected by gravity. As described above, the actuator unit 1 of the present embodiment is particularly effective in the grand piano 100 in which the thickness direction of the soundboard 120 is oriented in a substantially vertical direction.

[0056] In the actuator unit 1 of the present embodiment, the center of curvature C1 of the spherical convex surface 41a of the first spherical member 41 and the spherical concave surface 42a of the second spherical member 42 are located on the axis A1 of the actuator 2. Therefore, the first and second spherical members 41 and 42 can be moved relative to each other while the spherical convex surface 41a and the spherical concave surface 42a are in reliable surface contact. Therefore, the orientation of the actuator 2 can reliably follow the change in the orientation of the soundboard 120.

[0057] In the first embodiment, the two members (for example, the first and second flat surface members 31 and 32 ) constituting the movement allowing portion 3 and movable in a state of surface contact with each other may be formed of a material that easily slides only on their surfaces.

[0058] In the first embodiment, for example, a lubricant may be interposed between two members that constitute the movement allowing portion 3 and are movable in a state of surface contact with each other. When the lubricant is interposed, the two members can slide more easily.

[0059] [Second embodiment]

[0060] Next, refer to Figure 4 In the description of the second embodiment, the same components of the second embodiment as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

[0061] like Figure 4 As shown, the actuator unit 1D of the second embodiment is applied to the same grand piano 100 as that of the first embodiment. The actuator unit 1D of the second embodiment includes an actuator 2D and a movement allowing portion 3D, similarly to the first embodiment.

[0062] The actuator 2D has the same main body 11, vibrating body 12 and damper part 13 as those in the first embodiment. However, in the second embodiment, a bearing portion 23D is formed on the main body 11, and the bearing portion 23D is used to bear the support portion 60D of the movement allowing portion 3D described later. The bearing portion 23D is recessed in a concave shape and is located on the axis A1 of the main body 11. The bearing portion 23D may be formed directly on the magnetic path forming portion 14, for example. In the second embodiment, the bearing portion 23D is formed on a cover portion 24D that blocks the through hole 16C of the yoke portion 16. The cover portion 24D may be as shown in FIG. Figure 4 Although it is provided near the front end portion of the cylindrical portion 16B as in the illustrated example, it may be provided near the base end portion of the cylindrical portion 16B (near the disc portion 16A), for example.

[0063] The movement allowing portion 3D is arranged in the direction of the axis A1 of the actuator 2D with respect to the actuator 2D as in the first embodiment. Also, the movement allowing portion 3D is arranged near the second end of the body 11 in the direction of the axis A1 as in the first embodiment, but is not fixed to the actuator 2D.

[0064] The movement allowing portion 3D has the same planar sliding bearing 30D as that of the first embodiment. Figure 4 The illustrated plane sliding bearing 30D is formed by stacking three flat surface members 31D, 32D, and 33D, but may be formed by stacking two flat surface members 31D and 32D as in the first embodiment.

[0065] The movement allowing portion 3D of the second embodiment further includes a support portion 60D protruding from the plane sliding bearing 30D. The support portion 60D protrudes toward the main body 11 of the actuator 2D to support the actuator 2D so that it can swing. The specific structure of the support portion 60D may be arbitrary.

[0066] The support portion 60D of the second embodiment has a base portion 61D, a rod-shaped portion 62D, and a spherical portion 63D. The base portion 61D is fixed to one of the three flat surface components 31D, 32D, and 33D. The rod-shaped portion 62D extends from the base portion 61D in the upper direction in the vertical direction (positive direction of the Z axis). The spherical portion 63D is provided at the front end of the rod-shaped portion 62D. The spherical portion 63D is accommodated in the supporting portion 23D of the main body 11. Thus, the actuator 2D can swing with the spherical portion 63D (supporting portion 23D) as a fulcrum. The fulcrum (supporting portion 23D) of the actuator 2D is preferably located at a position that is closer to the upper side in the vertical direction than the center of gravity of the actuator 2D (especially the main body 11), for example.

[0067] In the piano 100 equipped with the actuator unit 1D of the second embodiment, the actuator 2D is movable relative to the frame 110 via the movement allowing portion 3D, similarly to the first embodiment. Therefore, even if the mounting position of the soundboard 120 where the actuator 2D is mounted changes with the aging of the soundboard 120, the orientation and position of the actuator 2D can follow the change of the soundboard 120.

[0068] For example, when the mounting portion of the soundboard 120 is displaced in the direction along the surface of the soundboard 120 (X-axis direction, Y-axis direction), the actuator 2D is displaced in the direction along the surface of the soundboard 120 relative to the frame 110 through the plane sliding bearing 30D as in the first embodiment. In addition, when the mounting portion of the soundboard 120 is displaced in the plate thickness direction (Z-axis direction) of the soundboard 120, the vibrator 12 of the actuator 2D is displaced in the vibration direction (Z-axis direction) of the vibrator 12 relative to the body 11. That is, the actuator unit 1D of the second embodiment has three degrees of freedom of translation as in the first embodiment.

[0069] On the other hand, when the orientation of the mounting portion of the soundboard 120 changes, the actuator 2D is swung relative to the frame 110 through the support portion 60D, thereby making it possible to make the orientation of the actuator 2D (particularly the orientation of the vibration direction of the vibrator 12) follow the orientation change of the soundboard 120. Specifically, in accordance with the orientation change of the soundboard 120 with the X-axis as the axis, the actuator 2D is swung with the X-axis as the axis, thereby making the orientation of the actuator 2D follow the orientation change of the soundboard 120. Similarly, in accordance with the orientation change of the soundboard 120 with the Y-axis as the axis, the actuator 2D is swung with the Y-axis as the axis, thereby making the orientation of the actuator 2D follow the orientation change of the soundboard 120. In addition, in accordance with the orientation change of the soundboard 120 with the Z-axis as the axis, the plurality of flat surface members 31D, 32D, and 33D are relatively rotated with the Z-axis as the axis, thereby making the orientation of the actuator 2D follow the orientation change of the soundboard 120.

[0070] As described above, the movement allowing portion 3D of the second embodiment has three degrees of freedom of rotation, similar to the first embodiment.

[0071] According to the actuator unit 1D of the second embodiment, the same effects as those of the first embodiment are achieved.

[0072] In the actuator unit 1D of the second embodiment, the actuator 2D can be rotatably moved relative to the frame 110 by the support portion 60D. Thus, even if the orientation of the mounting portion of the soundboard 120 to which the actuator 2D is mounted changes, the orientation of the actuator 2D (particularly the orientation of the vibration direction of the vibrator 12) can follow the orientation change of the soundboard 120 by the support portion 60D.

[0073] [Third embodiment]

[0074] Next, refer to Figure 5 In the description of the third embodiment, the same components of the third embodiment as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

[0075] like Figure 5 As shown, the actuator unit 1E of the third embodiment is applied to a soundboard 120E whose plate thickness direction is generally oriented in the horizontal direction ( Figure 5 The actuator unit 1E of the third embodiment includes an actuator 2 and a movement allowing portion 3 similar to those of the first embodiment.

[0076] The movement allowing portion 3 is fixed to the main body 11 of the actuator 2 in the same manner as in the first embodiment. However, the movement allowing portion 3 of the third embodiment is arranged in the radial direction of the actuator 2 (the direction orthogonal to the vibration direction of the vibrating body 12) relative to the actuator 2. Specifically, the first spherical surface component 41, the second spherical surface component 42 and the second flat surface component 32 formed integrally with the movement allowing portion 3, and the first flat surface component 31 are arranged in this order in the radial direction of the actuator 2 in the direction away from the actuator 2 ( Figure 5 The negative direction of the Z axis).

[0077] The movement allowing portion 3 may be directly fixed to the main body 11, or may be fixed to the main body 11 as shown in FIG. Figure 5 As shown in the example, the intermediate member 7E is fixed to the main body 11 via the intermediate member 7E. The specific structure of the intermediate member 7E may be arbitrary.

[0078] Figure 5The illustrated intermediate member 7E is formed by bending a plate-like member, etc., and has first and second plate portions 71E and 72E extending in directions orthogonal to each other. The first plate portion 71E is fixedly overlapped on the top plate 15 in the direction of the axis A1 of the main body 11. On the other hand, the second plate portion 72E is fixedly overlapped on the first spherical member 41 opposite to the main body 11 in the radial direction of the main body 11.

[0079] The actuator unit 1E is mounted on the piano 100E so as to connect the frame 110E and the soundboard 120E of the piano 100E, similarly to the first embodiment. That is, the connection portion 20 of the actuator unit 1E is fixed to the soundboard 120E, and the movement allowing portion 3 of the actuator unit 1E is fixed to the frame 110E.

[0080] However, in the piano 100E of the third embodiment, when the actuator unit 1E is attached to the soundboard 120E, the axis A1 of the actuator 2 (the vibration direction of the vibrating body 12) is oriented substantially in the horizontal direction ( Figure 5 On the other hand, the movement-allowing portion 3 is located vertically below the actuator 2 (in the negative direction of the Z axis) as in the first embodiment. The movement-allowing portion 3 may be as follows: Figure 5 The embodiment shown in the figure is directly fixed to the frame 110E, but may also be fixed via an intermediary member 5 (see Figure 2 ) etc. and are fixed to the frame 110E.

[0081] In the piano 100E equipped with the actuator unit 1E of the third embodiment, the actuator 2 is movable relative to the frame 110E via the movement allowing portion 3, similarly to the first embodiment. Therefore, even if the mounting position of the soundboard 120E to which the actuator 2 is mounted changes due to the aging change of the soundboard 120E, the orientation and position of the actuator 2 can follow the change of the soundboard 120E.

[0082] For example, when the mounting portion of the soundboard 120E is displaced in the horizontal direction (Y-axis direction) along the surface of the soundboard 120E, the actuator 2 is displaced in the horizontal direction along the surface of the soundboard 120E relative to the frame 110E through the plane sliding bearing 30. In addition, when the mounting portion of the soundboard 120E is displaced in the plate thickness direction (X-axis direction) of the soundboard 120E, the actuator 2 is displaced in the plate thickness direction of the soundboard 120E relative to the frame 110E through the plane sliding bearing 30. That is, the actuator unit 1E of the third embodiment has a two-axis degree of freedom of translation.

[0083] On the other hand, when the orientation of the mounting portion of the soundboard 120E changes, the first and second spherical components 41 and 42 move relatively to each other in a state where the spherical convex surface 41a and the spherical concave surface 42a are in surface contact, similarly to the first embodiment. As a result, the first spherical component 41 rotates relative to the second spherical component 42 about the X-axis as the axis in accordance with the orientation change of the soundboard 120E about the X-axis, and the orientation of the actuator 2 follows the orientation change of the soundboard 120E. In addition, the first spherical component 41 rotates relative to the second spherical component 42 about the Y-axis as the axis in accordance with the orientation change of the soundboard 120E about the Y-axis, and the orientation of the actuator 2 follows the orientation change of the soundboard 120E. Furthermore, in response to the change in the orientation of the soundboard 120E with the Z axis as the axis, the first and second spherical components 41, 42 rotate relative to each other with the Z axis as the axis, or the first and second flat surface components 31, 32 rotate relative to each other with the Z axis as the axis, thereby the orientation of the actuator 2 follows the change in the orientation of the soundboard 120E.

[0084] As described above, the movement allowing unit 3 of the third embodiment has the degree of freedom of rotation about three axes, similar to the first embodiment.

[0085] According to the actuator unit 1E of the third embodiment, the same effects as those of the first embodiment are achieved.

[0086] In the actuator unit 1E of the third embodiment, the movement-allowing portion 3 is arranged in the radial direction of the actuator 2 relative to the actuator 2. In this case, in a state where the actuator unit 1E is arranged so that the axis A1 of the actuator 2 (the vibration direction of the vibrating body 12) is oriented in the horizontal direction, the first and second flat surface members 31 and 32 that slide on each other are arranged in the vertical direction. Similarly, in this state, the first and second spherical surface members 41 and 42 that slide on each other are arranged in the vertical direction. Therefore, it is possible to suppress the first and second flat surface members 31 and 32 from moving relative to each other due to gravity. Similarly, it is possible to suppress the first and second spherical surface members 41 and 42 from moving relative to each other due to gravity. That is, the movement-allowing portion 3 is not easily affected by gravity. As described above, the actuator unit 1E of the third embodiment is particularly effective in an upright piano 100E in which the thickness direction of the soundboard 120E is oriented approximately in the horizontal direction.

[0087] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the above embodiments, and various changes can be made without departing from the scope of the present invention. For example, the order of overlapping the flat surface component and the spherical surface component can be reversed, and the overlap of the spherical surface component can be set below the overlap of the flat surface component. In this case, the curvature of the spherical surface component can be appropriately adjusted according to the displacement of the actuator.

[0088] In one embodiment of the present invention, for example, the actuator unit may not have a connecting portion, and the vibrating body may be directly fixed to the soundboard.

[0089] The musical instrument including the actuator unit according to any embodiment of the present invention is not limited to a piano, and may be a stringed instrument including a soundboard such as a guitar.

[0090] Industrial Applicability

[0091] The present invention can also be applied to an actuator unit.

[0092] Description of the label

[0093] 1, 1D, 1E…Actuator unit

[0094] 2. 2D…Actuator

[0095] 3. 3D…Movement allowance

[0096] 11…Main body

[0097] 12…Vibrating body

[0098] 13…Shock absorber

[0099] 20…Connection

[0100] 23D…Bearing part

[0101] 30, 30D…Planar sliding bearings

[0102] 31 ... first flat surface member

[0103] 31a…Flat surface

[0104] 31D, 32D, 33D…Flat surface parts

[0105] 32 ... second flat surface member

[0106] 32a…Flat surface

[0107] 40…Spherical plain bearings

[0108] 41…first spherical component

[0109] 41a…spherical convex surface

[0110] 42…Second spherical component

[0111] 42a…spherical concave

[0112] 60D…Support

[0113] 100…Grand piano (musical instrument)

[0114] 100E…Upright piano (musical instrument)

[0115] 110, 110E…frame

[0116] 120, 120E…Soundboard

[0117] C1…Center of curvature

Claims

1. An actuator unit, comprising: an actuator that vibrates the soundboard of the musical instrument; and a movement allowing unit configured to connect the frame of the musical instrument and the actuator so that the actuator can move within a predetermined range relative to the frame, The actuator comprises: a main body; and a vibrating body that vibrates in a predetermined vibration direction relative to the main body. The movement allowing portion includes a spherical sliding bearing or a plane sliding bearing, and is configured to connect the frame and the main body so that the main body can move within a predetermined range relative to the frame.

2. The actuator unit according to claim 1, wherein: The movement allowing portion includes a plane sliding bearing, the plane sliding bearing including: a first flat surface member having a first flat surface; and a second flat surface member having a second flat surface in surface contact with the first flat surface. The first flat surface member and the second flat surface member are configured to be relatively movable in a state where the first flat surface and the second flat surface are in surface contact with each other.

3. The actuator unit according to claim 1 or 2, wherein: The movement allowing portion has a spherical sliding bearing, the spherical sliding bearing including: a first spherical member having a spherical convex surface; and a second spherical member having a spherical concave surface in surface contact with the spherical convex surface. The first spherical surface member and the second spherical surface member are configured to be relatively movable in a state where the spherical convex surface and the spherical concave surface are in surface contact with each other.

4. The actuator unit according to claim 1, wherein: The movement allowing portion has a spherical sliding bearing and a plane sliding bearing, The spherical sliding bearing includes: a first spherical component having a spherical convex surface; and a second spherical component having a spherical concave surface in surface contact with the spherical convex surface. The plane sliding bearing includes: a first flat surface member having a first flat surface; and a second flat surface member having a second flat surface in surface contact with the first flat surface. The first spherical surface member and the second spherical surface member are configured to be relatively movable in a state where the spherical convex surface and the spherical concave surface are in surface contact with each other. The first flat surface member and the second flat surface member are configured to be relatively movable in a state where the first flat surface and the second flat surface are in surface contact with each other. One of the first spherical surface member and the second spherical surface member and one of the first flat surface member and the second flat surface member are formed integrally.

5. The actuator unit according to claim 1 or 2, wherein: The movement allowing portion and the actuator are arranged in a vibration direction of the actuator.

6. The actuator unit according to claim 3, wherein: The movement allowing portion and the actuator are arranged in a vibration direction of the actuator, The centers of curvature of the spherical convex surface and the spherical concave surface are located on an axis of the actuator extending along the vibration direction.

7. The actuator unit according to claim 1 or 2, wherein: The movement allowing portion and the actuator are arranged in a direction orthogonal to a vibration direction of the actuator.

8. The actuator unit according to claim 2, wherein: The movement allowing portion includes a support portion that protrudes from the planar sliding bearing and supports the actuator so as to be swingable. 9 . A musical instrument comprising the actuator unit according to claim 1 .

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