Exterior member, method for molding exterior member, and electronic musical instrument

Abstract

The present application provides an exterior member that improves the directivity of sound emitted from a speaker and ensures strength, a molding method for the exterior member, and an electronic musical instrument. A back panel (15) of an electronic keyboard instrument (10) has a frame portion (110, 210) that has a plurality of sound emission holes (150, 250), and the frame portion (110, 210) has a first hole frame (111, 211) that has a sound emission hole (150, 250) forming surface (111a, 211a), and a plurality of second hole frames (112, 212) that have sound emission hole (150, 250) forming surfaces (111a, 211a) that are longer than the first hole frame (111, 211) in the thickness direction (Y-axis direction) of the frame portion (110, 210).

Description

Technical Field

[0001] This invention relates to external components, methods for forming external components, and electronic musical instruments. Background Technology

[0002] Conventionally, external components with multiple sound holes, such as speaker grilles, have been used in audio equipment such as electronic musical instruments or radios. For example, Patent Document 1 discloses a speaker grille in which multiple circular sound holes are arranged in an alternating grid pattern. This speaker grille is mounted on a housing such that it covers the sound hole portion of the housing. A speaker is disposed inside the sound hole portion. Summary of the Invention

[0003] The external component of the present invention has a frame portion having a plurality of sound holes, the frame portion including: a first hole frame having a forming surface of the sound holes; and a second hole frame having a forming surface of the sound holes that is longer than the first hole frame in the thickness direction of the frame portion.

[0004] The forming method of the external component of the present invention is the forming method of the external component described above, comprising: a step of closing a mold having a core mold and a cavity mold, wherein the core mold has a first pin corresponding to the forming surface of the first hole frame and a second pin corresponding to the forming surface of the second hole frame; and a step of injecting molten resin into the mold to form the frame portion, wherein the frame portion has a plurality of sound-emitting holes including the first hole frame and the second hole frame.

[0005] The electronic musical instrument of the present invention includes the aforementioned external components. Attached Figure Description

[0006] Figure 1 This is a perspective view of an electronic keyboard musical instrument having an external component (rear panel) according to an embodiment of the present invention.

[0007] Figure 2 This is a rear view of an electronic keyboard musical instrument equipped with an external component (rear panel) according to an embodiment of the present invention.

[0008] Figure 3 This is an enlarged rear view of an electronic keyboard musical instrument showing the first and second sound-emitting sections of the external components (rear panel) according to an embodiment of the present invention.

[0009] Figure 4 This is an external component (rear panel) according to an embodiment of the present invention. Figure 3 Sectional view IV-IV.

[0010] Figure 5 This is an external component (rear panel) according to an embodiment of the present invention. Figure 3 VV sectional view.

[0011] Figure 6 This is an external component (rear panel) according to an embodiment of the present invention. Figure 3 Sectional view VI-VI.

[0012] Figure 7A and Figure 7B This is a partially enlarged view of the identically shaped sound-emitting portion of the second sound-emitting portion of the external component (rear panel) according to an embodiment of the present invention. Figure 7A yes Figure 3 An enlarged view of part P. Figure 7B yes Figure 7A Sectional view of VIIb-VIIb.

[0013] Figure 8 This is an external component (rear panel) according to an embodiment of the present invention. Figure 3 Sectional view of VIII-VIII.

[0014] Figure 9 This is a perspective view of the second sound-emitting section of the external component (rear panel) of an embodiment of the present invention, viewed from the inside.

[0015] Figure 10 This is a view of the first sound-emitting part of the outer component (rear panel) of the embodiment of the present invention, viewed from the outside. It is a perspective view showing the surface formed by the core mold in a hollow display and the surface formed by the cavity mold in a grid display.

[0016] Figure 11 This is a view of the first sound-emitting part of the outer component (rear panel) of the embodiment of the present invention, viewed from the inside. It is a perspective view showing the surface formed by the core mold in a hollow display and the surface formed by the cavity mold in a grid display.

[0017] Figure 12A and Figure 12B This is a diagram illustrating the mold used to form the outer component (rear panel) according to an embodiment of the present invention. Figure 12A This is an enlarged rear view of the front (outer) side of the second sound hole, which serves as the rear panel of the product. Figure 12B Is with Figure 12A The cross-sectional view of the mold corresponding to section XIIb-XIIb. Detailed Implementation

[0018] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 The electronic keyboard musical instrument 10 (electronic musical instrument) shown is an audio device, comprising a 61-key keyboard 30 and an instrument housing 19. An operating section 31 with adjustment knobs 13 is provided on the upper surface 11 of the electronic keyboard musical instrument 10. Figure 2As shown, the instrument housing 19 is provided with a rear panel 15 as an external component and a back cover 12 disposed on the outside of the rear panel 15. On the rear panel 15 of the electronic keyboard instrument 10, a connector panel 18 is provided in the lower center, which has an AC adapter connection port, a connection port for other audio equipment, and a USB connection port.

[0019] In addition, in the following description, the vertical direction of the electronic keyboard instrument 10 is set as the Z-axis (the lower side is the positive side of the Z-axis), the horizontal direction which is the arrangement direction of the keys is set as the X-axis (the side with the higher pitch is the positive side of the X-axis), and the front-back direction of the keys is set as the Y-axis (the side of the key closer to the front is the positive side of the Y-axis).

[0020] On the rear panel 15 of the electronic keyboard instrument 10, two first sound-emitting sections 100 and two second sound-emitting sections 200 are respectively provided. Each first sound-emitting section 100 and second sound-emitting section 200 has a frame portion 110 and 210 having multiple sound holes 150 and 250. The first sound-emitting section 100 is axially aligned with the sound holes 150 and 250. Figure 2 The direction orthogonal to the Y-axis direction, i.e., the thickness direction of frame parts 110 and 210. Figure 2 The two first sound-emitting sections 100 are arranged in a straight line along the X-axis direction. Furthermore, the two first sound-emitting sections 100 are arranged on the outer side of the electronic keyboard instrument 10 (opposite to the connector panel 18) along the X-axis direction, and the two second sound-emitting sections 200 are arranged on the inner side of the electronic keyboard instrument 10 (on the connector panel 18 side) along the X-axis direction. Figure 2 The first sound output section 100 and the second sound output section 200 are symmetrically arranged on the left and right sides.

[0021] like Figure 4 As shown, a sound-emitting device 20, corresponding to the first sound-emitting unit 100 and the second sound-emitting unit 200 respectively, is provided on the inner side (positive side in the Y-axis direction) of the back panel 15. In this embodiment, the sound-emitting device 20 is a loudspeaker. The back panel 15 (first sound-emitting unit 100, second sound-emitting unit 200) is arranged close to the sound-emitting device 20. A back cover 12 is provided on the outer side of the back panel 15. The portion of the back cover 12 corresponding to the first sound-emitting unit 100 and the second sound-emitting unit 200 is open. In addition, although not shown, a yarn mesh may be provided on the outer surface of the back cover 12.

[0022] like Figure 3As shown, the outer edges of the frame portions 110 and 210 are generally elliptical in shape with the X-axis as the major axis. The frame portions 110 and 210 include multiple frames 115 and 215. Here, frames 115 and 215 are sides that form, for example, hexagonal sound holes 150 and 250, and the frame portions 110 and 210 are composed of multiple frames 115 and 215. Furthermore, the sound holes 150 and 250 are provided within the area surrounded by the multiple frames 115 and 215. Additionally, as... Figure 4 As shown, the outer surfaces (outer surfaces 110a, 210a) of the frame portions 110 and 210 (negative sides in the Y-axis direction) are set to be coplanar.

[0023] The first sound output section 100 will be described below. For example... Figure 3 As shown, the sound holes 150 provided in the frame portion 110 of the first sound output section 100 include a plurality of first sound holes 160-1 to sixth sound holes 160-6 and a plurality of identical sound holes 170. The first sound output section 100 has a plurality of identical sound holes 170 on its inner side (connector panel 18 side) in a direction orthogonal to the thickness direction (Y-axis direction) of the frame portion 110. Additionally, the frame portion 110 of the first sound output section 100 has a relatively long, linear frame 120-1 to 120-6. The linear frames 120-1 to 120-4 are configured to be parallel to the Z-axis direction and connected to the outer edge of the frame portion 110. The linear frames 120-1 and 120-2 are arranged at approximately the center of the frame portion 110 in the X-axis direction, spaced apart by a predetermined interval, with the linear frame 120-1 located on the inner side and the linear frame 120-2 located on the outer side.

[0024] Linear frame 120-3 is positioned inside linear frame 120-1 in the X-axis direction, and linear frame 120-4 is positioned outside linear frame 120-2 in the X-axis direction. Furthermore, the portions of linear frames 120-3 and 120-4 that overlap with the hexagonal edges of the second sound hole 160-2 are also used as inclined portions (second inclined portion 162b). Linear frames 120-5 and 120-6 are configured to be parallel to the X-axis direction and connected to the outer edge of frame portion 110. Linear frames 120-5 and 120-6 are positioned near the outer edge of frame portion 110 in the Z-axis direction, with linear frame 120-5 positioned below and linear frame 120-6 positioned above.

[0025] On the inner side of the frame portion 110 in the X-axis direction relative to the central straight frame 120-1, between the upper and lower straight frames 120-5 and 120-6, a plurality of similarly shaped sound holes 170, which are polygonal in shape and approximately hexagonal in shape, are provided in a generally honeycomb pattern on the frame portion 110. For example... Figure 4As shown, the similar-shaped sound holes 170 are configured such that the inner and outer shapes of the sound holes 150 are approximately the same along the axial direction (Y-axis direction). Here, similar-shaped sound holes 170, 171, 270, etc., refer to holes 150 whose inner and outer shapes are approximately the same along the axial direction (Y-axis direction, i.e., the thickness direction of the frame portion 110). The similar-shaped sound holes 170 connected to the outer edge of the frame portion 110 and the straight frames 120-5 and 120-6 are configured to deform or form half of a generally hexagonal shape.

[0026] On the other hand, in the frame portion 110 located outside the straight frame 120-2 in the X-axis direction and between the straight frames 120-5 and 120-6, a plurality of first sound holes 160-1 to third sound holes 160-3, each in a generally honeycomb shape and with a generally hexagonal shape, are provided. The plurality of first sound holes 160-1 to third sound holes 160-3 are arranged in three rows, each in a row in the X-axis direction. (See reference...) Figure 3 Multiple first sound holes 160-1 are located at the top, multiple second sound holes 160-2 are located in the middle, and multiple third sound holes 160-3 are located at the bottom. Furthermore, in Figure 3 In the middle, the inclined surfaces of the first sound hole 160-1 to the seventh sound hole 160-7 are shown with shading.

[0027] When the first sound hole 160-1 is in Figure 5 When explaining using the first sound hole 161 in the cross-sectional view as an example, the first sound hole 160-1 is located within the area of ​​the first sound hole 161. Figure 3 In a top view, within the approximately hexagonal inner region, there is a first inclined portion 161b, which has a first inclined surface 161a. This first inclined surface 161a is arranged inclined from the axial direction of the first sound hole 161 (Y-axis direction, i.e., the thickness direction of the frame portion 110), i.e., the thickness direction of the frame portion 110. The first direction 161c, which is the inclination direction of the first inclined surface 161a (orthogonal to the edge line 161a1 of the first inclined surface 161a inside the hole, and the direction from the inside of the first sound hole 161 outward, i.e., the sound emission direction), is a direction that is approximately half an angle between the negative side of the X-axis and the negative side of the Z-axis.

[0028] Similarly, in the second sound hole 160-2 Figure 4Taking the second sound emission hole 162 in the cross-sectional view as an example, the second sound emission hole 162 has a second inclined portion 162b in the region of the second sound emission hole 162. The second inclined portion 162b has a second inclined surface 162a, which is arranged inclined from the axial direction (Y-axis direction) of the second sound emission hole 162, that is, the thickness direction of the frame portion 110. Furthermore, the second direction 162c, which is the inclination direction of the second inclined surface 162a, is set to the direction on the negative side of the X-axis.

[0029] Similarly, the third sound hole 160-3 (third sound hole 163) has a third inclined portion 163b with a third inclined surface 163a, and the third direction 163c, which is the direction of the third inclined surface 163a, is a direction that takes approximately a half angle between the negative side of the X-axis and the positive side of the Z-axis. The directions of the first direction 161c, the second direction 162c, and the third direction 163c are different.

[0030] On the other hand, on the outer sides of each of the upper and lower straight frames 120-5 and 120-6, a plurality of quadrilateral-shaped fourth sound holes 160-4 and a plurality of quadrilateral-shaped fifth sound holes 160-5 are arranged in a row along the X-axis direction. In the fourth sound holes 160-4 (fourth sound holes 164), the fourth direction 164c, which is the positive side of the Z-axis, is the direction of the fourth inclined surface 164a of the fourth inclined portion 164b. In the fifth sound holes 160-5 (fifth sound holes 165), the fifth direction 165c, which is the negative side of the Z-axis, is the direction of the fifth inclined surface 165a of the fifth inclined portion 165b. The fourth inclined portion 164b and the fifth inclined portion 165b each have inclined surfaces (fourth inclined surface 164a and fifth inclined surface 165a) that are inclined in the thickness direction of the frame portion 110.

[0031] On the other hand, a similarly shaped sound hole 172 is provided between the straight frames 120-1 and 120-2 in the central part, and approximately in the center of the frame portion 110 in the Z-axis and X-axis directions. A sixth sound hole 160-6 and a seventh sound hole 160-7, which are approximately elongated rectangular in shape in the Z-axis direction, are provided on the upper (negative side) and lower (positive side) side of the similarly shaped sound hole 172 in the Z-axis direction.

[0032] like Figure 6As shown, the sixth inclined surface 166a of the sixth inclined portion 166b of the sixth sound hole 160-6 is inclined from the thickness direction of the frame portion 110. In other words, the sixth inclined surface 166a is configured to expand from the inside to the outside of the frame portion 110. The sixth inclined portion 166b is provided with a curved portion that bends in the expanding direction. Similarly, the seventh inclined surface 167a of the seventh inclined portion 167b of the seventh sound hole 160-7 has the same curved portion as the above-mentioned curved portion, and is inclined from the thickness direction of the frame portion 110. The inclination direction of the sixth inclined surface 166a of the sixth sound hole 160-6 is the same as the fourth direction 164c. The inclination direction of the seventh inclined surface 167a of the seventh sound hole 160-7 is the same as the fifth direction 165c. Inclined portions (sixth inclined portion 166b and seventh inclined portion 167b) having inclined surfaces (sixth inclined surface 166a and seventh inclined surface 167a) are respectively provided between the second hole frames 112 described later. Furthermore, the inclined portions (sixth inclined portion 166b and seventh inclined portion 167b) are arranged in a pair with their inclined surfaces (sixth inclined surface 166a and seventh inclined surface 167a) facing each other.

[0033] Thus, from Figure 3 From the top view, the sound emission direction from the first sound emission unit 100 is the upper right direction (first direction 161c) according to the first sound emission hole 160-1, the right direction (second direction 162c) according to the second sound emission hole 160-2, the lower right direction (third direction 163c) according to the third sound emission hole 160-3, the upper direction (fourth direction 164c) according to the fourth and sixth sound emission holes 160-4 and 160-6, and the lower direction (fifth direction 165c) according to the fifth and seventh sound emission holes 160-5. Therefore, the first sound emission unit 100 can broaden the emitted sound.

[0034] Furthermore, here, we focus on the height (length of the frame portion 110 in the thickness direction (Y-axis direction) of the plurality of frames 115 constituting the frame portion 110 of the first sound-emitting section 100). Figure 7A and Figure 7B The following explanation uses the identical sound holes 171 and 172 as examples. The plurality of frames 115 constituting the frame portion 110 of the first sound-emitting section 100 have a first hole frame 111 and a second hole frame 112 having a forming surface of a sound hole 150. For example... Figure 3 The enlarged view of part P is Figure 7AAs shown, the shaped sound hole 171 is formed by the forming surfaces 111a of the holes provided by the six first hole frames 111 (reference numerals a to f). Similarly, the shaped sound hole 172 is formed by the forming surfaces 112a of the holes provided by the six second hole frames 112 (reference numerals g to l). Furthermore, the forming surfaces 111a and 112a are the side surfaces of the holes along the thickness direction (Y-axis direction) of the frame portion 110. Therefore, even if the forming surface is an extended shape, the length of the forming surface is in the thickness direction of the frame portion 110.

[0035] Then, as Figure 7B As shown, in the second hole frame 112, the length T2 of the forming surface 112a in the Y-axis direction (thickness direction of the frame portion 110) of the same-shaped sound hole 172 is longer than the length T1 of the forming surface 111a in the thickness direction of the frame portion 110 in the first hole frame portion 111 of the same-shaped sound hole 171. Since the outer surface 110a of the frame portion 110 is coplanar, the inner surface 110b of the central portion of the frame portion 110 is convex in the second hole frame 112. Figure 4 As shown, the second hole frame 112 can be provided corresponding to the central recess of the speaker cone 21 of the sound output device 20. Furthermore, the second hole frame 112 has a portion located inside the speaker cone 21. The first hole frame 111 is not located inside the speaker cone 21.

[0036] Next, the second sound output section 200 will be explained. For example... Figure 3 and Figure 4 As shown, the sound holes 250 of the frame portion 210 of the second sound output unit 200 are composed of a plurality of identical sound holes 270. In other words, the second sound output unit 200 has a frame portion 210, replacing the plurality of sound holes 150 of the first sound output unit 100, including the first sound hole 160-1 to the seventh sound hole 160-7, and the frame portion 210 has sound holes 250 composed of identical sound holes 270. The plurality of identical sound holes 270 are approximately hexagonal in shape as polygons and are configured to be approximately honeycomb-like. In addition, similar to the first sound output unit 100, straight frames 220-1 to 220-6 are provided on the frame portion 210 of the second sound output unit 200.

[0037] Next, as Figure 9 As shown, the frame 215 of the second sound-emitting section 200 has a first hole frame 211 and a second hole frame 212, and the first hole frame 211 and the second hole frame 212 have forming surfaces 211a and 212a of the sound-emitting hole 250. Figure 8As shown, the length T4 of the axial (Y-axis direction, thickness direction of frame portion 210) forming surface 212a of the sound hole 250 in the second hole frame 212 is longer than the length T3 of the thickness direction (Y-axis direction) forming surface 211a of the frame portion 210 in the first hole frame 211. Furthermore, length T4 is shorter than length T2.

[0038] Similar to the sixth and seventh sound holes 160-6 and 160-7, the second hole frame 112 is convex in side view for the purpose of sound diffusion, so the inclined surface is set to be long, and thus the length T2 is set to be relatively long. On the other hand, since the frame 215 of the second sound output section 200 does not need to diffuse sound in terms of acoustic characteristics, the length T4 is shorter than the length T2. Furthermore, the configuration of the frame sections 110 and 210 is not limited to this embodiment, and the configuration, including changes to the lengths T2 and T4, can be changed according to the desired acoustic characteristics.

[0039] In the second sound-emitting section 200, a defined area Q approximately in the center of the frame section 210 is formed by the second hole frame 212, thereby increasing the strength of the frame section 210. Furthermore, as... Figure 4 As shown, the second hole frame 212 can be configured to correspond to the central recess of the speaker cone 21 of the sound output device 20.

[0040] Here, the back panel 15 is formed by resin injection molding. In this case, the forming surfaces of the holes 150 and 250 are provided with draft angles that widen from the outside to the inside of the back panel 15. For example, as Figure 7B and Figure 8 As shown, the forming surfaces 111a, 112a, 211a, and 212a are provided with draft angles by slightly widening from the outside to the inside of the back panel 15.

[0041] The mold 50 for forming the back panel 15 has a cavity mold 51 and a core mold 52. (The text then abruptly shifts to a description of the first sound-emitting section 100.) Figure 10 , Figure 11 In the middle, the shaded area (the surface of the back panel 15) is formed using the cavity mold 51, and the hollow area is formed using the core mold 52. Additionally, as... Figure 10 As shown, four bosses 15a for mounting the back cover 12 are provided on the outer periphery of the surface (outer side) of the first sound-emitting section 100. Figure 11 Around the inner side of the first sound-emitting section 100 shown, there is a boss 15b for connecting to the instrument housing 19 of the electronic keyboard instrument 10.

[0042] In the forming of the hexagonal holes 170 and 270, hexagonal prism-shaped protrusions can be provided on the core mold 52 for forming. In the forming of the first sound hole 160-1 to the third sound hole 160-3, since the inclined portions (first inclined portion 161b to third inclined portion 163b) are formed, the cavity mold 51 and the core mold 52 have the following structure.

[0043] In mold 50, a hexagonal prism 53 having a pair of inclined surfaces 51a and 52a that are inclined in the same direction on opposite sides is divided between opposite tops M1 and M2, and a pin 51b, which is one side of the divided hexagonal prism 53, is provided in cavity mold 51, and a pin 52b, which is the other side, is provided in core mold 52.

[0044] The molding method for the back panel 15, which is an outer component using the mold 50, includes a process of closing the mold 50 and a process of injecting molten resin into the closed mold 50. Thus, a frame portion 110 is formed, which is provided with a first sound hole 160-1 to a third sound hole 160-3. The first sound hole 160-1 to the third sound hole 160-3 have inclined surfaces (such as a first inclined surface 161a) in the area of ​​the hole via hexagonal prisms 53.

[0045] Thus, in the cavity mold 51 and core mold 52 of the first sound hole 160-1 to the third sound hole 160-3, the line connecting the opposing tops M1 and M2 of the hexagon is set as the parting line PL.

[0046] In addition, using Figure 7A , Figure 7B Explain the forming methods of the first hole frames 111 and 211 and the second hole frames 112 and 212. Figure 7A , Figure 7B This refers to the periphery of the similarly shaped sound holes 171 and 172 in the first sound-emitting section 100. For example... Figure 7B As shown, the core mold 52 of the mold 50 has a first pin 52c corresponding to the forming surface 111a of the first hole frame 111 and a second pin 52d corresponding to the forming surface 112a of the second hole frame 112. Furthermore, the forming method using the back panel 15 of the mold 50 is the same as described above, including a mold closing process for closing the mold 50 and a process for injecting molten resin. Thus, a frame portion 110 having a plurality of sound holes 150 including the first hole frame 111 and the second hole frame 112 is formed.

[0047] in addition, Figure 7A and Figure 7B The first sound output section 100 has been described, but the same applies to the first hole frame 211 and the second hole frame 212 of the second sound output section 200.

[0048] In the above embodiments of the present invention, the back panel 15 of the electronic keyboard musical instrument 10, which is an external component, has a frame portion 110, 210 having a plurality of sound holes 150, 250. The frame portion 110, 210 has a first hole frame 111, 211 and a second hole frame 112, 212. The first hole frame 111, 211 has a forming surface 111a, 211a of the sound holes 150, 250. The second hole frame 112, 212 has a forming surface 111a, 211a of the sound holes 150, 250 that is longer than the first hole frame 111, 211 in the thickness direction (Y-axis direction) of the frame portion 110, 210.

[0049] Therefore, the sound holes 150 and 250 provided through the second hole frames 112 and 212 can be made into cylindrical shapes that are longer than the sound holes 150 and 250 provided through the first hole frames 111 and 211. This improves the directivity of the sound from the sound reproduction device 20 and also locally increases the strength of the frame portions 110 and 210. Furthermore, while it is possible to increase the axial length of all sound holes 150 and 250, this would increase the overall size of the device with the external mounting components.

[0050] Furthermore, the second hole frames 112 and 212 are disposed in the center of the frame portions 110 and 210. As a result, the cylindrical sound holes 150 and 250 formed by the second hole frames 112 and 212 can be easily disposed at the center of the sound emitted from the sound emission device 20.

[0051] Furthermore, inclined portions (sixth inclined portion 166b and seventh inclined portion 167b) are provided between the second hole frames 112, each having an inclined surface (sixth inclined surface 166a and seventh inclined surface 167a) inclined from the thickness direction (Y-axis direction) of the frame portion 110. This allows for the arbitrary setting of the sound emission direction while improving the directivity of the sound.

[0052] Furthermore, the inclined portions (sixth inclined portion 166b and seventh inclined portion 167b) are provided with a pair of inclined surfaces, which are arranged such that the inclined surfaces (sixth inclined surface 166a and seventh inclined surface 167a) are opposite each other. As a result, the inclined surfaces (sixth inclined surface 166a and seventh inclined surface 167a) on the inner side of the rear panel 15, which is an outer component, become narrower, thereby increasing the sound pressure level and producing sound.

[0053] Furthermore, the frame portions 110 and 210 are provided with straight frames 120-1 to 120-6 and 220-1 to 220-6. This further improves the strength of the frame portions 110 and 210.

[0054] Furthermore, the outer surfaces (outer surfaces 110a and 210a) of the frame portions 110 and 210 are made coplanar. As a result, a back panel 15 with an inner protrusion due to the second hole frames 112 and 212 can be obtained, which has a good appearance and is easy to install fabric components such as yarn mesh.

[0055] Furthermore, a loudspeaker serving as the sound emission device 20 is provided at a position corresponding to the second hole frames 112 and 212. By using the second hole frames 112 and 212, which are cylindrical in shape to form the sound emission holes, the directivity of the sound emitted from the loudspeaker can be improved.

[0056] Furthermore, a portion of the inner side of the second hole frame 112 is located inside the speaker cone 21 of the speaker. Since only the portion of the frame portion 110 corresponding to the recess of the speaker cone 21 enters the interior of the speaker cone 21, the frame portion 110 is less likely to collide with the speaker cone 21 due to vibration. In addition, since the frame portion 110 (rear panel 15) can approach the speaker cone 21, the electronic keyboard instrument 10 can be miniaturized.

[0057] Furthermore, in the first sound-emitting section 100 and the second sound-emitting section 200, which are respectively equipped with frame portions 110 and 210, the length T2 of the forming surface 112a of the same shape sound-emitting hole 172 (sound-emitting hole 150) in the thickness direction of the frame portion 110 in the second hole frame 112 of the first sound-emitting section 100 is longer than the length T4 of the forming surface 212a of the sound-emitting hole 250 in the thickness direction of the frame portion 210 in the second hole frame 212 of the second sound-emitting section 200. Therefore, the lengths T2 and T4 of the forming surfaces of the first hole frames 111, 211 and the second hole frames 112, 212 can be set according to the desired acoustic characteristics.

[0058] Furthermore, a rear panel 15, serving as an external component, is provided on the electronic keyboard instrument 10, which is an electronic musical instrument. This allows for the provision of an electronic musical instrument with an external component that enhances both the directivity and intensity of the sound.

[0059] Furthermore, the method for forming the back panel 15 includes: a step of closing a mold 50 having a core mold 52 and a cavity mold 51, the core mold 52 having a first pin 52c corresponding to the forming surfaces 111a, 211a of the first hole frames 111, 211 and a second pin 52d corresponding to the forming surfaces 112a, 212a of the second hole frames 112, 212; and a step of injecting molten resin into the mold 50 to form frame portions 110, 210, the frame portions 110, 210 having a plurality of sound-emitting holes 150, 250 including the first hole frames 111, 211 and the second hole frames 112, 212. Thus, a method for forming the back panel 15 that improves sound directivity and strength can be provided.

[0060] Furthermore, the draft angles in the forming surfaces 111a and 211a of the first hole frames 111 and 211, and the forming surfaces 112a and 212a of the second hole frames 112 and 212, are designed to expand from the outside to the inside of the frame portions 110 and 210. This provides a method for forming a back panel 15 that improves sound pressure and sound emission characteristics, particularly in the shaped sound holes 170 and 270.

[0061] While several embodiments of the invention have been described, these embodiments are provided by way of example and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included within the scope and spirit of the invention, and are included within the scope of the invention described in the claimed scope and its equivalents.

Claims

1. An external component, wherein, It has a frame section with multiple sound holes. The frame portion includes: The first hole frame has the surface for forming the sound hole; and The second hole frame has a forming surface for the sound-emitting hole that is longer in the thickness direction of the frame portion than the first hole frame. The frame section also includes: The first sound hole is defined by the second hole frame and is located in the central region of the frame portion; A plurality of second sound holes, defined by the first hole frame, are disposed outside the area where the second hole frame is configured; and A pair of third sound holes, at least partially defined by the second hole frame, are positioned opposite each other on either side of the first sound hole and are arranged adjacent to the first sound hole. An inclined portion is provided between the second hole frames. The inclined portion has an inclined surface that is inclined from the thickness direction of the frame portion and is formed to be coplanar with the frame portion.

2. The external component according to claim 1, wherein, It also has a second frame section, which has a fourth sound outlet. The second frame section includes: The third hole frame has the forming surface of the fourth sound hole; and The fourth hole frame has a forming surface for the fourth sound hole that is longer in the thickness direction of the second frame portion than the third hole frame. The second hole frame is configured to be closer to the center of the frame portion than the first hole frame. The fourth hole frame is configured to be closer to the center of the second frame portion than the third hole frame.

3. The external component according to claim 1, wherein, The inclined portion is provided with a pair of opposite inclined surfaces.

4. The external component according to claim 1, wherein, The inclined surface of the inclined portion is the forming surface of the third sound hole.

5. The external component according to claim 1, wherein, The frame portion has a linear frame.

6. The external component according to claim 1, wherein, The outer surfaces of the frame are configured to be coplanar.

7. The external component according to claim 1, wherein, The speaker cone has a recess in the center. The length of the second hole frame in the thickness direction is set according to the depth of the recess in the central part of the speaker cone.

8. The external component according to claim 2, wherein, The fourth sound hole, defined by the fourth hole frame, is configured to correspond to the recess in the center of the speaker cone of the loudspeaker.

9. An electronic musical instrument comprising the external component as described in any one of claims 1 to 8.

10. A method for forming an external component, as described in any one of claims 1 to 8, wherein, have: The process of closing a mold having a core mold and a cavity mold, wherein the core mold has a first pin corresponding to the forming surface of the first hole frame and a second pin corresponding to the forming surface of the second hole frame; as well as The process of injecting molten resin into the mold to form the frame portion, wherein the frame portion has a plurality of sound-emitting holes including the first hole frame and the second hole frame.

11. The forming method according to claim 10, wherein, The draft angles in the forming surfaces of the first hole frame and the second hole frame are set to expand from the outside to the inside of the frame portion.

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