Acoustic device

Abstract

This acoustic device is provided with: a first rotating body that can rotate about a first axis of rotation; a second rotating body that can rotate about the first axis of rotation independently of the first rotating body; an imparting unit that is provided to the first rotating body and is pressed against the second rotating body to impart a frictional force thereto; and a regulating unit that is provided to a structure different from the first rotating body and the second rotating body and that regulates the frictional force applied by the imparting unit.

Description

sound equipment

[0001] The present disclosure relates to acoustic devices.

[0002] 2. Description of the Related Art There is known an audio device that includes a jog dial for controlling the playback of music. The jog dial has a first rotor that rotates around a rotation axis and a second rotor that rotates around a rotation axis.

[0003] The first rotating body has an annular portion formed in an annular shape centered on the rotation axis and is also called a platter, while the second rotating body has a disk portion provided inside the annular portion and formed in a disk shape centered on the rotation axis and is also called a vinyl.

[0004] During playback of music, a driving force is applied to the first rotating body, causing the first rotating body to rotate around the rotation axis. Frictional force is applied between the first rotating body and the second rotating body, causing the second rotating body to rotate integrally with the first rotating body.

[0005] An operator operating the audio device can rotate the second rotating body at a different speed and in a different direction than the first rotating body by touching the top surface of the second rotating body and applying a force exceeding the frictional force. The audio device plays music by adjusting the playback direction and playback speed of the music according to the rotation direction and rotation speed of the second rotating body.

[0006] Patent document 1 discloses an acoustic device that allows the frictional force between a first rotating body and a second rotating body to be adjusted, thereby changing the force applied when rotating the second rotating body.

[0007] International Publication No. 2023 / 119669

[0008] In the acoustic device disclosed in Patent Document 1, the frictional force is adjusted by varying the thickness, material, number, etc. of the frictional force adjusting member sandwiched between the first rotating body and the second rotating body. Therefore, the second rotating body must be removed to adjust the frictional force, which is a cumbersome process. Furthermore, the level of the frictional force after adjustment cannot be confirmed unless the second rotating body is installed. Furthermore, if the frictional force after adjustment is not satisfactory, it is necessary to remove the second rotating body again and change the frictional force adjusting member, which results in a significant workload when changing the frictional force.

[0009] An object of the present disclosure is to provide an acoustic device that can easily change the frictional force between a first rotating body and a second rotating body.

[0010] The acoustic device according to the present disclosure comprises a first rotating body rotatable around a first rotation axis, a second rotating body rotatable around the first rotation axis independently of the first rotating body, an application unit provided on the first rotating body and pressed against the second rotating body to apply a frictional force, and an adjustment unit provided on a structure different from the first rotating body and the second rotating body and for adjusting the frictional force applied by the application unit.

[0011] According to the present disclosure, it is possible to obtain an acoustic device that can easily change the frictional force between the first rotating body and the second rotating body.

[0012] FIG. 1 is a plan view of an acoustic device according to a first embodiment. FIG. 2 is a perspective view of the second acoustic operation unit as viewed from above. FIG. 3 is a perspective view of the second acoustic operation unit as viewed from below. FIG. 4 is an exploded perspective view of the second acoustic operation unit. FIG. 5 is a perspective view of the base unit as viewed from above. FIG. 6 is a perspective view of the first rotating body as viewed from below. FIG. 7 is a perspective view of the first rotating body as viewed from below. FIG. 8 is a view of the second acoustic operation unit cut along line VIII-VIII shown in FIG. 1 and viewed obliquely from above. FIG. 9 is a perspective view of the second rotating body as viewed from above. FIG. 10 is a perspective view of the second rotating body as viewed from below. FIG. 11 is a partially enlarged cross-sectional view of a portion where the application unit and the adjustment unit are provided. FIG. 12 is a side view of the application unit as viewed along the circumferential direction. FIG. 13 is a plan view of the application unit as viewed from above. FIG. 14 is a side view of the application unit as viewed along the radial direction. Fig. 15 is a cross-sectional view taken along line XV-XV shown in Fig. 13. Fig. 16 is a side view of the adjustment unit. Fig. 17 is a plan view of the adjustment unit viewed in the vertical direction. Fig. 18 is a partially enlarged cross-sectional view of the support unit inserted into the hole in the base unit, as viewed from diagonally above. Fig. 19 is a side view of the support unit. Fig. 20 is a plan view of the support unit viewed in the vertical direction. Fig. 21 is a partially enlarged view of the portion of the annular steel plate where the protrusion is formed, as viewed from diagonally above.

[0013] An acoustic device according to an embodiment of the present disclosure will be described in detail below with reference to the drawings. However, the present disclosure is not limited to the embodiment described below.

[0014] [Embodiment 1] Fig. 1 is a plan view of an audio device according to embodiment 1. The audio device 1 includes a housing 2, a first audio operation unit 3 and a second audio operation unit 4 provided on a top surface 21 of the housing 2, and a control unit (not shown) provided inside the housing 2. In the audio device 1, the control unit outputs an operation signal or outputs an audio signal of a song whose playback state has been adjusted in response to an operation performed by an operator on the first audio operation unit 3 and the second audio operation unit 4. The output destination of the operation signal and the audio signal is, for example, a music playback device (not shown) connected to the audio device 1. The music playback device plays the song based on the input operation signal or audio signal.

[0015] A plurality of first acoustic operation units 3 are provided on the top surface 21 of the housing 2. The first acoustic operation units 3 include a button-type operation unit that is operated by pressing, and a slider-type operation unit that is operated by sliding.

[0016] The second acoustic operation unit 4 is provided on the top surface 21 of the housing 2. In the audio device 1, two second acoustic operation units 4 are provided side by side. Fig. 2 is a perspective view of the second acoustic operation unit as seen from above. Fig. 3 is a perspective view of the second acoustic operation unit as seen from below. Fig. 4 is an exploded perspective view of the second acoustic operation unit.

[0017] The second acoustic operation unit 4 includes a first rotating body 5, a second rotating body 6, an applying unit 8 (see FIG. 8 ), and an adjusting unit 9 (see FIG. 8 ), which are rotatable around a common first rotation axis 11. The second acoustic operation unit 4 also includes a base unit 7 that rotatably supports the first rotating body 5 and the second rotating body 6.

[0018] Here, the terms for directions used in the following description will be defined. First, the direction along the first rotation axis 11 when the first rotation axis 11 is parallel to the vertical direction is defined as the up-down direction. Furthermore, a Z axis parallel to the up-down direction is defined, with the positive direction along the Z axis being upward and the negative direction along the Z axis being downward. Furthermore, the circumferential direction refers to the circumferential direction of a circle centered on the first rotation axis 11. Furthermore, the radial direction refers to the radial direction of a circle centered on the first rotation axis 11. Note that the directions defined here are defined for convenience in explaining the present disclosure and do not specify the posture of the acoustic device 1 when in use.

[0019] <Base portion> Figure 5 is a perspective view of the base portion as viewed from above. The base portion 7 is fixed to the top surface 21 of the housing 2. The base portion 7 is formed in a circular shape when viewed in the up-down direction. A recess 71 that is recessed from top to bottom is formed in the base portion 7. A shaft portion 72 that extends along the first rotation shaft 11 is formed in the center of the recess 71. The shaft portion 72 is formed in a cylindrical shape. The first rotating body 5 is rotatably fixed to the shaft portion 72.

[0020] A peripheral portion 73 having an annular shape and an upper surface 73a facing upward is formed around the recess 71 of the base portion 7. A plurality of holes 74 are formed in the upper surface 73a of the peripheral portion 73, into which support portions (described later) are inserted. Furthermore, a plurality of holes 75 are formed in the upper surface 73a, into which biasing portions (described later) are inserted. The plurality of holes 74 and the plurality of holes 75 are aligned in the circumferential direction. Furthermore, a plurality of protrusions 76 protruding upward are aligned in the circumferential direction on the upper surface 73a.

[0021] <First Rotating Body> Figure 6 is a perspective view of the first rotating body as seen from above. The first rotating body 5 is formed in a circular shape when viewed in the up-down direction. A recess 51 that is recessed from top to bottom is formed in the first rotating body 5. An opening 51a that connects the inside and outside of the recess 51 is formed in the inner wall surface of the recess 51. An application portion 8 is provided outside the opening 51a. The configuration and function of the application portion 8 will be described in detail later. A protrusion 51b that protrudes inward is formed in the inner wall surface of the recess 51.

[0022] The first rotating body 5 is formed with a peripheral portion 52 having an upper surface 52a facing upward and formed in an annular shape surrounding the recessed portion 51. The first rotating body 5 is provided with an annular portion 53 formed in an annular shape surrounding the peripheral portion 52. As shown in FIG. 1 , the annular portion 53 is exposed on the top surface 21 side of the housing 2. The annular portion 53 is a part known as a platter, which rotates while the performance of a piece of music is being controlled. A through-hole 54 is formed in the center of the recessed portion 51, penetrating it vertically. The central axis of the through-hole 54 overlaps with the first rotating shaft 11.

[0023] Fig. 7 is a perspective view of the first rotating body as seen from below. Fig. 8 is a view of the second acoustic operation unit cut along line VIII-VIII shown in Fig. 1 as seen from diagonally above.

[0024] A cylindrical portion 55 is formed on the bottom surface of the first rotor 5, extending downward from the edge of the through-hole 54. As shown in Fig. 8, two bearings 56 are fitted inside the cylindrical portion 55. The bearings 56 are, for example, ball bearings, and have an outer ring 56a and an inner ring 56b.

[0025] An outer ring 56a of the bearing 56 is fixed to the inner wall surface of the cylindrical portion 55. An inner ring 56b of the bearing 56 is fixed to the shaft portion 72 of the base portion 7. This allows the first rotating body 5 to be rotatably supported on the base portion 7. The number of bearings 56 provided is not limited to two. Furthermore, the bearings 56 are not limited to ball bearings.

[0026] <Regarding the Drive Unit> The acoustic device 1 is provided with a drive unit 12 that rotates the first rotating body 5. As shown in Fig. 8 , the drive unit 12 is configured to have a plurality of coils 121 and a plurality of magnets 122. The plurality of coils 121 are provided on the bottom surface of the recess 71 of the base portion 7. The plurality of coils 121 are arranged in a circumferential direction so as to surround the periphery of the shaft portion 72. The plurality of magnets 122 are provided on the bottom surface of the recess 51 of the first rotating body 5. The plurality of magnets 122 are arranged in a circumferential direction so as to surround the periphery of the through hole 54. The drive unit 12 configured in this manner functions as an electric motor, and by passing current through the coils 121, the first rotating body 5 can be rotated together with the magnets 122 around the first rotating shaft 11.

[0027] <Second Rotating Body> As shown in FIGS. 4 and 8 , the second rotating body is provided inside the annular portion 53 of the first rotating body 5 .

[0028] 9 is a perspective view of the second rotating body 6 as seen from above. FIG. 10 is a perspective view of the second rotating body 6 as seen from below. The second rotating body 6 has a disk portion 61 and a cylindrical portion 62.

[0029] The disc portion 61 is a plate-like member formed in a circular shape centered on the first rotating shaft 11. The disc portion 61 is formed to a size that covers the upper surface 52a of the peripheral portion 52 provided on the first rotating body 5. The top surface of the disc portion 61 is exposed on the top surface side of the housing 2. The disc portion 61 is a part that rotates integrally with the first rotating body 5 while the performance of a piece of music is being controlled, and is what is called a vinyl.

[0030] As shown in Figure 10, the cylindrical portion 62 is a cylindrical portion extending downward from the disk portion 61. A step portion 62a is provided in the cylindrical portion 62 so that the outer diameter at the bottom is larger than the outer diameter at the top (see also Figure 8). The step portion 62a engages with the protrusion 51b, which will be described later. The outer diameters of the upper and lower cylindrical portions do not need to be different as long as the shape allows engagement with the protrusion 51b. For example, a groove extending in the circumferential direction may be formed in the cylindrical portion 62, and the protrusion 51b may engage with the groove.

[0031] When the second rotating body 6 is provided inside the annular portion 53 of the first rotating body 5, the cylindrical portion 62 is inserted into the recessed portion 51 of the first rotating body 5. When the cylindrical portion 62 is inserted, the convex portion 51b provided on the inner wall surface of the recessed portion 51 of the first rotating body 5 engages from above with the stepped portion 62a of the cylindrical portion 62 of the second rotating body 6. This prevents the first rotating body 5 from falling off. Meanwhile, although the convex portion 51b engages with the stepped portion 62a from above, it does not engage with the cylindrical portion 62 in the circumferential direction, and therefore the second rotating body 6 is not prevented from rotating around the first rotating shaft 11.

[0032] A part of the outer surface of the cylindrical portion 62 serves as a contact surface 62b against which a part of the application portion 8 (described later) comes into contact. In the first embodiment, the entire circumferential area below the step portion 62a serves as the contact surface 62b, but the area above the step portion 62a may also serve as the contact surface 62b. Note that the portion where the step portion 62a is formed and the portion where the contact surface 62b is formed may be separate bodies as shown in FIG. 10 or may be integrated.

[0033] As shown in FIGS. 4 and 8 , a frictional force imparting sheet 13 is sandwiched between the peripheral portion 52 and the disc portion 61 of the first rotating body 5. The frictional force imparting sheet 13 is formed of, for example, felt or resin. With the frictional force imparting sheet 13 sandwiched between the peripheral portion 52 and the disc portion 61 of the first rotating body 5, the rotational force imparted by the drive unit 12 is transmitted to the second rotating body 6 via the first rotating body 5. This causes the second rotating body 6 to rotate integrally with the first rotating body 5. On the other hand, by applying a force to the second rotating body 6 in the forward or reverse direction of rotation that exceeds the frictional force imparted by the frictional force imparting sheet 13, the second rotating body 6 can be rotated independently of the first rotating body 5. An operator of the audio device 1 can rotate the second rotating body 6 in a direction or at a speed different from that of the first rotating body 5 by touching and applying a force to the disc portion 61 exposed from the top surface 21 of the housing 2.

[0034] The control unit transmits a signal to play the music in reverse or to change the playback speed of the music according to the rotation direction and rotation speed that have changed as a result of the application of force to the second rotating body 6. In the following description, applying force to the second rotating body 6 to change the rotation direction and rotation speed will also be simply referred to as performing a scratch.

[0035] <Regarding the Display Unit> As shown in Fig. 8, a space is formed inside the second rotating body 6, and the display unit 14 is provided in this space. The display unit 14 is installed with its display surface 14a, which can display various information, facing upward. The display unit 14 does not rotate because its rod-shaped portion 14b, which extends downward, is inserted into the inside of the shaft portion 72 of the base portion 7 and fixed therein. By forming part or all of the disc portion 61 of the second rotating body 6 from a translucent material, the various information displayed on the display surface 14a can be viewed by an operator or the like through the disc portion 61.

[0036] <Regarding the Applying Unit> Figure 11 is a partially enlarged cross-sectional view of the portion where the applying unit and the adjusting unit are provided. The applying unit 8 is attached to the first rotating body 5. Therefore, the applying unit 8 rotates integrally with the first rotating body 5. The applying unit 8 is pressed against the second rotating body 6 to apply a frictional force, and the frictional force is adjustable. As described above, the frictional force is applied by the frictional force applying sheet 13 sandwiched between the peripheral portion 52 of the first rotating body 5 and the disc portion 61 of the second rotating body 6. In addition, by applying a frictional force to the second rotating body 6 by the applying unit 8 attached to the first rotating body 5, the force required to perform the scratching can be adjusted.

[0037] Fig. 12 is a side view of the application portion viewed in the circumferential direction. Fig. 13 is a plan view of the application portion viewed from above. Fig. 14 is a side view of the application portion viewed in the radial direction. Fig. 15 is a cross-sectional view taken along line XV-XV shown in Fig. 13. In Figs. 13 and 15, the abutment surface 62b formed on the second rotating body 6 is shown by a two-dot chain line.

[0038] The application unit 8 includes a brake arm 81, a brake lever 82, and a spring 83. The brake arm 81 is attached to the first rotating body 5 so as to be rotatable around an arm-side fulcrum 81a. The brake arm 81 is provided so that one side surface faces the abutted surface 62b of the second rotating body 6. The side surface facing the abutted surface 62b of the second rotating body 6 forms an abutment portion 81b that abuts against the abutted surface 62b. Rotation around the arm-side fulcrum 81a causes the abutment portion 81b of the brake arm 81 to move toward or away from the abutted surface 62b. A hook portion 81c is formed on the brake arm 81. A spring 83 is hooked onto the hook portion 81c. The spring 83 applies a biasing force to the brake arm 81 so that the abutment portion 81b rotates in a direction away from the abutted surface 62b. A through-hole 81d that penetrates vertically is formed in the brake arm 81. As shown in Figure 6, the brake arm 81 enters the inside of the recess 51 of the first rotating body 5 through an opening 51a formed in the recess 51, and abuts the abutting portion 81b against the abutted surface 62b of the second rotating body 6.

[0039] The brake lever 82 is attached to the first rotor 5 so as to be rotatable around a lever-side fulcrum 82a. The brake lever 82 has an action portion 82b extending downward from the lever-side fulcrum 82a and a force point portion 82c extending radially outward from the lever-side fulcrum 82a. As shown in Figure 15, a magnet 82d, which serves as a first attraction portion, is attached to the tip of the force point portion 82c. The area through which the magnet 82d passes as it rotates together with the first rotor 5 is circular when viewed in the up-down direction.

[0040] The tip of the action portion 82b is inserted into a through-hole 81d formed in the brake arm 81. When the brake lever 82 rotates (in the direction indicated by arrow A2) so that the tip of the force point portion 82c moves downward, the action portion 82b moves radially inward. Therefore, by moving the tip of the force point portion 82c downward, the force point portion 82c can be brought into contact with the inner wall surface of the through-hole 81d, thereby pushing the brake arm 81 radially inward (see also FIG. 11 ). When the brake arm 81 is pushed radially inward, the abutment portion 81b is pressed strongly against the abutted surface 62b of the second rotating body 6, increasing the frictional force applied to the abutted surface 62b.

[0041] That is, by varying the force that moves the force point 82c of the brake lever 82 downward, the strength with which the abutment portion 81b is pressed against the abutted surface 62b of the second rotating body 6 can be varied, thereby adjusting the frictional force applied to the abutted surface 62b. The acoustic device 1 is provided with an adjustment unit 9 that attracts the force point 82c of the brake lever 82 from below to move the force point 82c downward, and that adjusts the frictional force by varying the suction force.

[0042] <Regarding the Adjustment Unit> Fig. 16 is a side view of the adjustment unit, and Fig. 17 is a plan view of the adjustment unit as viewed in the up-down direction.

[0043] The adjustment unit 9 is attached to the base unit 7 and an auxiliary base unit 7a attached to the base unit 7. The base unit 7 and the auxiliary base unit 7a are structures different from the first rotating body 5 and the second rotating body. Therefore, unlike the application unit 8, the adjustment unit 9 does not rotate together with the first rotating body 5.

[0044] The adjustment unit 9 has an annular steel plate 91 as a second attraction portion. The annular steel plate 91 is a plate-shaped member formed into an annular shape when viewed in the vertical direction. The annular steel plate 91 is formed of a magnetic steel plate, but may be formed of other magnetic materials. The annular steel plate 91 is disposed opposite the circular movement path of the magnet 82d as a first attraction portion that rotates together with the first rotor 5. Therefore, the annular steel plate 91 is always positioned opposite the magnet 82d regardless of the rotational position of the first rotor 5. Because the annular steel plate 91 is magnetic, a magnetic force is generated between the annular steel plate 91 and the opposing magnet 82d, attracting each other. This can be said to generate a magnetic force that attracts the force point portion 82c on which the magnet 82d is provided, or to generate a magnetic force that attracts the annular steel plate 91.

[0045] A plurality of protrusions 91a protruding downward are formed on the annular steel plate 91. The protrusions 91b are formed at positions facing the holes 75 formed in the base portion 7.

[0046] The adjustment unit 9 has a movement mechanism 92. The movement mechanism 92 moves the annular steel plate 91 up and down to move the annular steel plate 91 between a position close to the force point 82c of the brake lever 82 and a position away from it.

[0047] The movement mechanism 92 has multiple support portions 92a that support the annular steel plate 91 from below. The multiple support portions 92a are inserted into holes 74 formed in the base portion 7 shown in FIG. 5 . That is, the multiple support portions 92a are arranged in a circumferential direction centered on the first rotation shaft 11. FIG. 18 is a partially enlarged cross-sectional view, viewed from diagonally above, of the support portion inserted into the hole in the base portion. Each of the multiple support portions 92a is rotatable about a second rotation shaft 92c parallel to the first rotation shaft 11. As the support portions 92a rotate, the annular steel plate 91 moves upward or downward depending on the direction of rotation. For example, if the support portions 92a are threaded and screwed into a threaded hole formed in the annular steel plate 91, the rotation of the support portions 92a can move the annular steel plate up and down.

[0048] Fig. 19 is a side view of the support part. Fig. 20 is a plan view of the support part as viewed in the vertical direction. As shown in Fig. 19 and Fig. 20, the support part 92a is a rod-shaped member extending vertically, and a plurality of teeth are formed on the outer surface of the support part 92a to form a gear 92b.

[0049] 21 is a partially enlarged view of the portion of the annular steel plate where the protrusion is formed, viewed from diagonally above. The movement mechanism 92 has a biasing portion 92d that biases the annular steel plate 91 in a direction to move it upward. The biasing portion 92d is, for example, a compression coil spring. One end of the biasing portion 92d is inserted into a hole 75 formed in the base portion 7. The other end of the biasing portion 92d is inserted into the protrusion 91a formed on the annular steel plate 91.

[0050] 16 and 17 , the movement mechanism 92 has a ring gear 92e formed in an annular shape surrounding a plurality of support portions 92a. The ring gear 92e is rotatable about the first rotation shaft 11. Specifically, as shown in FIGS. 18 and 21 , the ring gear 92e is placed on the upper surface 73a of the peripheral portion 73 of the base portion 7. A recess 92f extending in the circumferential direction is formed on the lower surface of the ring gear 92e. The recess 92f formed in the ring gear 92e fits into the protrusion 76 formed on the upper surface 73a of the base portion 7, thereby allowing the ring gear 92e to rotate about the first rotation shaft 11.

[0051] A plurality of teeth 92g that mesh with the gears 92b formed on the plurality of support portions 92a are formed and arranged in the circumferential direction on the inner peripheral surface of the ring gear 92e. Therefore, when the ring gear 92e rotates about the first rotation shaft 11, the plurality of support portions 92a can be rotated collectively about the second rotation shaft 92c. In addition, a plurality of teeth 92h that are formed and arranged in the circumferential direction on the outer peripheral surface of the ring gear 92e.

[0052] The adjustment unit 9 has a friction force operation unit 93. The friction force operation unit 93 is provided on the outer periphery of the first rotating body 5. The friction force operation unit 93 is exposed from the top surface 21 of the housing 2. The friction force operation unit 93 is rotatable around a third rotation axis 93a that is parallel to the first rotation axis 11. The friction force operation unit 93 is a part that can be rotated by an operator. A gear 93b is formed on the friction force operation unit 93. An intermediate gear 94 that meshes with the gear 93b is provided around the friction force operation unit 93. The teeth formed on the intermediate gear 94 also mesh with teeth 92h formed on the outer periphery of the annular gear 92e.

[0053] Therefore, by rotating the friction force operating unit 93, the ring gear 92e can be rotated. Rotating the ring gear 92e rotates the support portion 92a, thereby moving the ring steel plate 91 up and down. By moving the ring steel plate 91 up and down, the distance between the magnet 82d provided at the force point portion 82c of the brake lever 82 and the ring steel plate 91 can be varied (see also FIG. 15 ). If the distance between the magnet 82d and the ring steel plate 91 is shorter, i.e., if the ring steel plate 91 is moved upward, the force with which the ring steel plate 91 attracts the magnet 82d increases, and the force with which the abutting portion 81b of the brake arm 81 is pressed against the abutted surface 62b of the second rotating body 6 increases. On the other hand, if the distance between the magnet 82d and the annular steel plate 91 increases, i.e., if the annular steel plate 91 is moved downward, the force with which the annular steel plate 91 attracts the magnet 82d decreases, and the force with which the abutment portion 81b of the brake arm 81 is pressed against the abutted surface 62b of the second rotating body 6 decreases.

[0054] <Effects> In the acoustic device 1 described above, the force required for the operator to perform a scratch changes as the frictional force applied to the second rotating body 6 from the frictional force applying unit 8, which rotates together with the first rotating body 5. Therefore, by simply performing the simple operation of rotating the frictional force operating unit 93, the operator can adjust the force required to perform a scratch.

[0055] Furthermore, because the adjustment unit 9 is attached to a structure different from the first rotating body 5 and the second rotating body 6, the force required to perform a scratch can be adjusted by operating the friction force operating unit 93 even when the first rotating body 5 and the second rotating body 6 are rotating. Therefore, the operator can adjust the force required to perform a scratch while controlling the performance of a piece of music using the acoustic device 1.

[0056] Note that the portion of the annular steel plate 91 that faces the magnet 82d is attracted by the magnet 82d, which is the first attraction portion. Because the magnet 82d rotates together with the first rotor 5, the portion of the annular steel plate 91 that is attracted to the magnet constantly changes. Therefore, the portion of the annular steel plate 91 that is pulled upward moves in accordance with the rotation of the first rotor 5, which can cause the annular steel plate 91 to vibrate and generate noise and other problems. On the other hand, in the acoustic device 1, the biasing portion 92d constantly biases the entire annular steel plate 91 in a direction that moves it upward, thereby preventing vibration and noise from occurring when a force that pulls upward is applied only to a portion of the annular steel plate 91.

[0057] Although the example in which the first attraction portion is a magnet and the second attraction portion is a magnetic material has been described, this is not limiting. For example, the first attraction portion may be a magnetic material and the second attraction portion may be a magnet. Furthermore, both the first attraction portion and the second attraction portion may be magnets. Furthermore, the magnet may be an electromagnet. In this case, the attraction force can be varied by varying the supplied power, thereby adjusting the frictional force.

[0058] Furthermore, although an example in which the ring gear 92e is provided radially outward from the support portion 92a has been described, it may be provided radially inward from the support portion 92a.

[0059] 1 Acoustic device, 2 Housing, 21 Top surface, 3 First acoustic operation unit, 4 Second acoustic operation unit, 5 First rotating body, 51 Recess, 51a Opening, 51b Convex portion, 52 Surrounding portion, 52a Top surface, 53 Annular portion, 54 Through hole, 55 Cylindrical portion, 56 Bearing, 56a Outer ring, 56b Inner ring, 6 Second rotating body, 61 Circumferential plate portion, 62 Cylindrical portion, 62a Step portion, 62b Contact surface, 7 Base portion, 7a Auxiliary base portion, 71 Recess, 72 Shaft portion, 73 Surrounding portion, 73a Top surface, 74, 75 Hole, 76 Convex portion, 8 Applying portion, 81 Brake arm, 81a Arm side fulcrum, 81b Contact portion, 81c Hook portion, 81d Through hole, 82 Brake lever, 82a Lever-side fulcrum, 82b action portion, 82c force point portion, 82d magnet, 83 spring, 9 adjustment portion, 91 annular steel plate, 91a convex portion, 92 movement mechanism, 92a support portion, 92b gear, 92c second rotation shaft, 92d biasing portion, 92e annular gear, 92f concave portion, 92g, 92h tooth portion, 93 friction force operation portion, 93a third rotation shaft, 93b gear, 94 intermediate gear, 11 first rotation shaft, 12 drive portion, 121 coil, 122 magnet, 13 friction force applying sheet, 14 display portion, 14a display surface

Claims

1. An acoustic device comprising: a first rotating body that is rotatable around a first rotation axis; a second rotating body that is rotatable around the first rotation axis independently of the first rotating body; an application unit that is provided on the first rotating body and is pressed against the second rotating body to apply a frictional force; and an adjustment unit that is provided on a structure different from the first rotating body and the second rotating body and that adjusts the frictional force applied by the application unit.

2. The acoustic device described in claim 1, wherein the first rotating body has an annular portion formed in a ring shape centered on the first rotation axis, the second rotating body is provided inside the annular portion, the application portion has a force point portion that rotates around a fulcrum and a contact portion that contacts the second rotating body in conjunction with the rotation of the force point portion, and the adjustment portion adjusts the force with which the contact portion is pressed against the second rotating body by changing the force applied to the force point portion.

3. The acoustic device described in claim 2, wherein the application portion comprises a brake arm having the contact portion and a brake lever having the force point portion, the brake lever having an action portion formed integrally with the force point portion and extending from the fulcrum in a direction different from that of the force point portion, and the action portion abuts against the brake arm and changes the force applied to the brake arm as the brake lever rotates.

4. The acoustic device described in claim 3, wherein a first suction portion is provided at the force point portion, and the adjustment portion has a second suction portion provided opposite to the area through which the first suction portion passes as the first rotating body rotates, and one of the first suction portion and the second suction portion is a magnet and the other is a magnetic material, or both are magnets.

5. The acoustic device according to claim 4, wherein the adjustment section has a movement mechanism that moves the second suction section between a position close to the force point and a position distant from the force point.

6. The acoustic device described in claim 5, wherein the action portion extends downward from the fulcrum, the force point portion extends from the fulcrum in a direction away from the first rotation axis, the force with which the action portion is pressed against the second rotating body increases as the force point portion moves downward, the second suction portion is provided below the force point portion, and the movement mechanism moves the second suction portion up and down.

7. The acoustic device described in claim 6, wherein the movement mechanism comprises: a plurality of support parts that support the second suction part from below, are arranged in a row along the circumferential direction of a circle centered on the first rotation axis, and move the second suction part up and down by rotating around a second rotation axis parallel to the first rotation axis; a gear that is provided on each of the plurality of support parts and has the second rotation axis as its central axis; and a ring gear that meshes with the gear from the inside or outside of the plurality of support parts to rotate the plurality of support parts.

8. The acoustic device according to claim 7, wherein the movement mechanism further comprises a biasing portion that biases the second suction portion in a direction of upward movement.

9. An acoustic device as described in claim 7, wherein the adjustment unit is provided on the outer periphery of the first rotating body when viewed along the first rotation axis, and has a friction force operating unit that rotates the annular gear when operated.

10. The acoustic device described in claim 9, wherein the friction force operating unit is rotatable around a third rotation axis parallel to the first rotation axis, and the operation of rotating the ring gear is a rotation operation around the third rotation axis.

Images