Sound emitting device and electronic keyboard instrument

Abstract

To provide a sound emitting device and an electronic keyboard instrument in which reproduction capability of low-pitched sound is improved while downsizing (thinning) of a housing.SOLUTION: A sound emitting device 28L includes a box-shaped receiving frame 30L having an open upper surface, and an integrally molded sound emitting member 28L1 placed on the receiving frame 30L. The sound emitting member 28L1 and the receiving frame 30L form a housing space 54LS for housing the speaker 62L, an acoustic space 56LS connected to the housing space 54LS, and a duct 58L connected to the housing space 54LS, and the acoustic space 56LS fixes the receiving frame 30L and the sound emitting member 28L1. The receiving frame 30L is a space corresponding to a region including a plurality of lower bosses 44b and 44c provided side by side in a left-right direction, and is provided with a port 50L that opens at a position corresponding to the duct 58L.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a sound emitting device and an electronic keyboard instrument. [Background technology]

[0002] There is a demand for smaller housings for electronic keyboard instruments from the standpoint of portability, storage, and other convenience. However, as the housing becomes smaller, the sound emitted from the rear side (back surface) of the speaker's diaphragm may interfere with the sound emitted from the front side (front surface) of the speaker's diaphragm, resulting in a deterioration in the quality of the bass. Therefore, Patent Document 1 discloses a technology that prevents the deterioration of the quality of the bass even when the housing is made smaller. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 6-26386 Summary of the Invention [Problem to be solved by the invention]

[0004] The electronic keyboard instrument described in Patent Document 1 is designed so that the sound emitted from the rear of the speaker does not interfere with the sound emitted from the front of the speaker. However, because low-pitched sounds tend to diffract more than high-pitched sounds, the diffraction of the sound emitted from the sound output hole 9 in Figure 1 causes interference between the sound emitted from the rear of the speaker and the sound emitted from the front of the speaker, making it difficult to completely guarantee low-pitched sounds. Therefore, an object of the present invention is to provide a sound output device and an electronic keyboard instrument that have improved low-pitched sound reproduction capabilities while achieving a smaller (thinner) housing. [Means for solving the problem]

[0005] A sound emitting device according to one embodiment of the present invention comprises a box-shaped receiving frame having an open top, and an integrally molded sound emitting member placed on the receiving frame, wherein the sound emitting member and the receiving frame form a storage space for storing a speaker, an acoustic space connected to the storage space, and a duct connected to the storage space, the acoustic space being a space corresponding to an area including a plurality of lower bosses which fix the receiving frame and the sound emitting member and are arranged side by side in the left-right direction, and the receiving frame is provided with a port which opens at a position corresponding to the duct.

[0006] An electronic keyboard instrument according to one aspect of the present invention includes the above-described sound emitting device. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a sound emitting device and an electronic keyboard instrument that have a smaller (thinner) housing and improved bass reproduction capabilities. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view of an electronic keyboard instrument according to an embodiment; [Figure 2] 1 is a perspective view of an electronic keyboard instrument according to an embodiment, disassembled into an upper case and a lower case. [Figure 3] FIG. 3 is a cross-sectional view taken along line II-II of FIG. 2. [Figure 4] 4 is a diagram showing the sound emitting device located on the right side of FIG. 3 disassembled into a sound emitting member, a speaker, and a receiving frame. [Figure 5] 4 is a perspective view of the sound emitting device located on the right side of FIG. 3, exploded into a sound emitting member and a receiving frame. [Figure 6] 5A is a top view of the sound emitting and containing member shown in FIG. 4 with the speaker removed, and FIG. 5B is a bottom view of the sound emitting and containing member shown in FIG. [Figure 7] 1 is a top view of a part of a lower case of a sound emitting device located at the rear right side of the electronic keyboard instrument according to an embodiment, from which a sound emitting member has been removed. FIG. [Figure 8] FIG. 8 is a cross-sectional view taken along line VII-VII shown in FIG. 7. [Figure 9]FIG. 4 is an enlarged view of a part on the right side of the cross-sectional view of FIG. 3. [Figure 10] FIG. 2 is a bottom view of the electronic keyboard instrument according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] The structure of an electronic keyboard instrument 1 according to one embodiment of the present invention will be described below with reference to FIGS. 1 to 10. The electronic keyboard instrument 1 shown in FIG. 1 includes a housing 10 and a keyboard 12 having a plurality of keys arranged in the longitudinal direction of the housing 10. The housing 10 contains sound-emitting devices 28L and 28R. Sound is emitted from the sound-emitting devices 28L and 28R in response to the player's operation of the keyboard 12. In the following description, as shown in FIG. 1, the direction in which the keys of the keyboard 12 are arranged is defined as the left-right direction (the left side of FIG. 1 is the left direction), and the direction in which the keys of the keyboard 12 extend is defined as the front-rear direction (the front side of FIG. 1 is the front direction). The left-right direction and the front-rear direction are perpendicular to each other. The direction perpendicular to the left-right and front-rear directions is defined as the up-down direction (the upper side of FIG. 1 is the up direction). The sound-emitting device 28L located on the left side of the electronic keyboard instrument 1 is responsible for emitting low-pitched sounds, and the sound-emitting device 28R located on the right side is responsible for emitting high-pitched sounds. In the following, the sound emitting device 28L that emits low-pitched sounds will be described in detail, and the explanation and illustration of the sound emitting device 28R may be omitted. Note that the structures of the sound emitting devices 28L, 28R included in the electronic keyboard instrument 1 are roughly symmetrical with respect to the center of the electronic keyboard instrument 1 in the left-right direction.

[0010] As shown in Fig. 1, the housing 10 has a generally elongated rectangular shape with the longitudinal direction extending in the left-right direction when viewed from above. As shown in Fig. 2, the housing 10 is divided into an upper case 14 and a lower case 16. The upper case 14 and the lower case 16 are each made of a resin material.

[0011] When viewed from above, the upper case 14 has a generally rectangular shape with a hollow portion 14a into which the keyboard 12 is fitted. The upper case 14 has a left portion 14L, a right portion 14R, a front portion 14F, and a rear portion 14B. The left portion 14L and the right portion 14R extend in the front-to-rear direction and are generally rectangular parallelepipeds with an open bottom. The rear portion 14B extends in the left-to-right direction and is generally rectangular parallelepipeds with an open bottom. The left side of the rear portion 14B is connected to the rear portion of the right side of the left portion 14L. The right side of the rear portion 14B is connected to the rear portion of the left side of the right portion 14R. The top surfaces of the rear portion 14B, the left portion 14L, and the right portion 14R are slightly inclined downward from rear to front. Various operating switches 18, such as a power switch, are arranged in a left-to-right array in the front center of the top surface of the rear portion 14B. A volume dial 20 is provided to the left of the operation switches 18. Speaker grills (not shown) corresponding to speakers 62L and 62R (described later) are provided on the left and right sides of the upper surface of the rear portion 14B. The front portion 14F has an upper main surface and a lower main surface and is shaped like a plate extending in the left-right direction. The left end of the front portion 14F is connected to the front end of the right surface of the left portion 14L. The right end of the front portion 14F is connected to the front end of the left surface of the right portion 14R. The lower surfaces of the left portion 14L, right portion 14R, and rear portion 14B and the lower main surface of the front portion 14F are located on the same plane.

[0012] As shown in FIG. 2, upper bosses 38La, 38Lb, and 38Lc are provided on the left side of the rear portion 14B to integrally fasten the upper case 14, the lower case 16, and the sound emitting device 28L. The upper bosses 38La, 38Lb, and 38Lc protrude downward from the inside of the rear portion 14B and have a generally truncated cone shape tapering downward. The upper bosses 38La, 38Lb, and 38Lc have hollow portions that threadably engage with the fixing screws 46. More specifically, as shown in FIG. 8, the outer edge of the lower end of the upper boss 38Lc is notched in an annular shape, and a protrusion 38Lc1 is formed at the lower end. The upper bosses 38La and 38Lb have the same shape as the upper boss 38Lc. The upper boss 38Lc is positioned to correspond to a case fixing hole 48c of the storage portion 54L (described later) and a lower boss 44c (described later). The upper bosses 38La, 38Lb are positioned to correspond to case fixing holes 48a, 48b of the acoustic unit 56L, which will be described later, and lower bosses 44a, 44b, which will be described later, respectively. Upper bosses 38Ra, 38Rb, 38Rc are provided on the right side of the rear portion 14B to integrally fix the upper case 14, the lower case 16, and the sound emitting device 28R. The shapes and positions of the upper bosses 38Ra, 38Rb, 38Rc are similar to those of the upper bosses 38La, 38Lb, 38Lc, so a description thereof will be omitted.

[0013] 2 and 3, the lower case 16 has a bottom surface 16B that is a generally rectangular shape extending in the left-right direction when viewed from above, and a side surface 16S that extends upward from the outer edge of the bottom surface 16B. The boundary between the bottom surface 16B and the side surface 16S has a curved shape. The upper end of the side surface 16S fits into the lower end of the upper case 14, thereby integrating the upper case 14 and the lower case 16.

[0014] As shown in FIGS. 2 and 3 , the keyboard 12, control boards 26L and 26R, and sound emitting devices 28L and 28R are provided inside the lower case 16. The keyboard 12 is located in the front of the lower case 16. The sound emitting devices 28L and 28R are located at the rear left and right corners of the lower case 16, respectively. The sound emitting device 28L includes a sound emitting member 28L1 and a receiving frame 30L. The sound emitting device 28R includes a sound emitting member 28R1 and a receiving frame 30R. The sound emitting member 28R1 and the receiving frame 30R are joined together without any gaps. The control boards 26L and 26R are arranged in parallel, from left to right, between the sound emitting devices 28L and 26R. A known keystroke mechanism is provided in the space between the keyboard 12 and the lower case 16 to achieve keystroke intervals and tone colors similar to those of a real piano when a player strikes each key on the keyboard 12.

[0015] As shown in FIG. 4, the bottom surface 16B has an upper main surface 16B1 and a lower main surface 16B2. As shown in FIG. 10, the lower main surface 16B2 is provided with a handle 22, rubber feet 24, and ports 50R and 50L (described later). The handle 22 is located at the center of the rear end of the lower main surface 16B2. When viewed from below, the handle 22 has a generally elongated rectangular shape with its longitudinal direction extending in the left-right direction and is recessed. The rubber feet 24 have a generally flat cylindrical shape and protrude downward. A plurality of rubber feet 24 are arranged at approximately equal intervals along the front and rear ends of the lower main surface 16B2. The rubber feet 24 contact a mounting surface (not shown) and support the housing 10. This creates a space between the lower main surface 16B2 and the mounting surface. The ports 50R and 50L are located symmetrically on either side of the handle 22.

[0016] As shown in FIGS. 3 to 5, a receiving frame 30L is provided in the upper left corner of the upper main surface 16B1. The receiving frame 30L is configured to mount and secure the sound emitting member 28L1 without creating any gaps. The receiving frame 30L is box-shaped and open at the top. Specifically, the receiving frame 30L is formed by a plate-like member extending from the upper main surface 16B1 and the upper main surface 16B1 surrounded by this plate-like member. When viewed from above, the receiving frame 30L has a generally elongated rectangular shape with the left-right direction as its longitudinal direction. The upper main surface 16B1 is provided with a plurality of U-shaped grooves 16B1d extending in the left-right direction. The U-shaped grooves 16B1d are recessed downward in a U-shape. More specifically, the cross section of the U-shaped grooves 16B1d perpendicular to the left-right direction has a recessed arc-shaped shape. Furthermore, the upper main surface 16B1 is provided with a duct rib 68 that protrudes slightly upward. The duct rib 68 has a right rib 68R, a front rib 68F, and a rear rib 68B, and is generally U-shaped when viewed from above with an open left end. The duct rib 68 is positioned to correspond to the surrounding wall 64, which will be described later. A port 50L, which will be described later, is located at the right end inside the duct rib 68. As shown in FIGS. 5 and 7, the receiving frame 30L has upright holes 32LF, 32LB, 32RF, 32RB, 32CF, 32CB, 34LF, 34LB, 34RF, and 34RB formed inside the receiving frame 30L for fixing the sound radiating member 28L1. The upright holes 32LF, 32LB, 32RF, 32RB, 32CF, 32CB, 34LF, 34LB, 34RF, and 34RB are cylindrical and protrude upward from the upper main surface 16B1, and have hollow portions that threadably engage with the mounting screws 36. 6, the vertical holes 32LF, 32LB, 32RF, 32RB, 32CF, and 32CB are positioned to correspond to the mounting holes 40LF, 40LB, 40RF, 40RB, 40CF, and 40CB of the port connection portion 52L, which will be described later. The vertical holes 34LF, 34LB, 34RF, and 34RB are positioned to correspond to the mounting holes 42LF, 42LB, 42RF, and 42RB of the acoustic portion 56L, which will be described later.

[0017] Furthermore, as shown in Fig. 5, lower bosses 44a, 44b, and 44c are provided on the inside of the receiving frame 30L to integrally fix the upper case 14, the lower case 16, and the sound emitting device 28L. Specifically, the lower bosses 44a, 44b, and 44c fix the receiving frame 30L and the sound emitting member 28L1. The lower bosses 44a, 44b, and 44c protrude upward from the upper main surface 16B1, have a generally truncated cone shape that tapers upward, and have hollow portions through which fixing screws 46 are inserted, as shown in Fig. 8. The outer edges of the upper ends of the lower bosses 44a, 44b, and 44c are cut out in an annular shape.

[0018] The lower boss 44a is positioned to correspond to the upper boss 38La and a case fixing hole 48a of the storage section 54L (described later). The lower bosses 44b and 44c are positioned to correspond to the acoustic section 56L. More specifically, the lower bosses 44b and 44c are positioned to correspond to the upper bosses 38Lb and 38Lc and case fixing holes 48b and 48c of the acoustic section 56L (described later), respectively. The lower bosses 44b and 44c enable the upper case 14, the lower case 16, and the sound emitting device 28L to be more firmly integrated and fixed to the acoustic section 56L, which extends in the left-right direction. The lower bosses 44a, 44b, and 44c are aligned in this order from right to left on the left-right axis Ax, as shown in FIG. 7 . This makes it easier for workers to insert the fixing screws 46 into the lower bosses 44a, 44b, and 44c during the process of integrating the upper case 14, sound-emitting member 28L1, receiving frame 30L, and lower case 16, thereby improving work efficiency.

[0019] As shown in Fig. 7, the lower boss 44a is provided near the upright hole 32RB located at the rear end so as not to contact the longitudinal axis Ay1 connecting the upright holes 32LF and 32LB, and to avoid the central portion of the receiving frame 30L in the longitudinal direction. This makes it less likely that communication between the storage area 54LA (see Fig. 9) described below and the duct 58L will be obstructed. In other words, air vibrations are smoothly transmitted from the storage area 54LA to the duct 58L.

[0020] The lower boss 44b is provided near the upright hole 34RB at the rear end so as not to contact the longitudinal axis Ay2 connecting the upright holes 34RF and 34RB, and to avoid the central portion of the receiving frame 30L in the longitudinal direction. This makes it difficult for communication between the acoustic region 56LA and the storage region 54LA, which will be described later, to be obstructed. In other words, air vibrations are smoothly transmitted between the acoustic region 56LA and the storage region 54LA.

[0021] As shown in FIG. 8 , the fixing screw 46 inserted from below through the hollow portion of the lower boss 44c is threadedly engaged with the hollow portion of the upper boss 38Lc via a case fixing hole 48c (described later). Therefore, with the sound emitting device 28L sandwiched between the upper case 14 and the lower case 16, the upper case 14 and the lower case 16 are fixed together. Specifically, the lower boss 44c fixes the receiving frame 30L and the acoustic unit 56L. More specifically, with the protrusion 38Lc1 of the upper boss 38Lc fitted into the hollow portion of the lower boss 44c via the case fixing hole 48c, the upper case 14, the sound emitting device 28L, and the lower case 16 are integrated together by the fixing screw 46. Similarly, the fixing screw 46 inserted from below through the hollow portion of the lower boss 44a is threadedly engaged with the hollow portion of the upper boss 38La via the case fixing hole 48a. A fixing screw 46 is inserted from below into the hollow portion of the lower boss 44b and threadedly engages with the hollow portion of the upper boss 38Lb via a case fixing hole 48b.

[0022] A port 50L is provided on the right side of the inner side of the receiving frame 30L. A storage area 54LA is interposed between the port 50L and an acoustic area 56LA (described later). This separates the port 50L from the acoustic area 56LA. The port 50L has a plurality of circular holes arranged in a matrix pattern that penetrate the bottom surface 16B in the vertical direction.

[0023] As shown in FIGS. 5 and 6, the sound emitting members 28L1 and 28R1 are generally rectangular in shape with the longitudinal direction extending left to right when viewed from above. The sound emitting member 28L1 is attached to a receiving frame 30L erected in the upper left corner of the upper main surface 16B1. The sound emitting member 28L1 includes a port connection portion 52L, a storage portion 54L, and an acoustic portion 56L. The port connection portion 52L, the storage portion 54L, and the acoustic portion 56L are integrally molded and arranged in this order from right to left to form the sound emitting member 28L1. The sound emitting member 28R1 is attached to a receiving frame 30R erected in the upper right corner of the upper main surface 16B1. The sound emitting member 28R1 includes a port connection portion 52R, a storage portion 54R, and an acoustic portion 56R. The port connection portion 52R, the storage portion 54R, and the acoustic portion 56R are integrally molded and arranged in this order from left to right to form the sound emitting member 28R1.

[0024] As shown in FIG. 6, the port connection portion 52L has a generally rectangular top surface 52L1 with its longitudinal direction extending left-right when viewed from above, a generally rectangular parallelepiped pit 52LP recessed downward from the inside of the top surface 52L1, and an enclosure wall 64. More specifically, the pit 52LP has a bottom surface 52LB with a left short side, a right short side, a front long side, and a rear long side, and left side, right side, front side, and rear side extending upward from each side of the bottom surface 52LB and connecting to the top surface 52L1. Therefore, the cross section of the port connection portion 52L perpendicular to the left-right direction is concave. Six mounting holes 40LF, 40LB, 40RF, 40RB, 40CF, and 40CB are provided in the top surface 52L1, penetrating the top surface 52L1 in the vertical direction. The upper surface 52L1 has a mounting hole 40LF located in the front left corner, a mounting hole 40LB located in the rear left corner, a mounting hole 40RF located in the front right corner, and a mounting hole 40RB located in the rear right corner. A mounting hole 40CF is located approximately in the center between the mounting holes 40LF and 40RF, and a mounting hole 40CB is located approximately in the center between the mounting holes 40LB and 40RB. As shown in FIG. 5 , mounting screws 36 inserted from above into the mounting holes 40LF, 40LB, 40RF, 40RB, 40CF, and 40CB threadably engage with the vertical holes 32LF, 32LB, 32RF, 32RB, 32CF, and 32CB provided in the receiving frame 30L. This attaches the port connection portion 52L to the receiving frame 30L. More specifically, the lower outer edge of the upper surface 52L1 is placed on and fixed to the upper end of the receiving frame 30L. An elastic sealant is attached to the joint between the lower outer edge of the top surface 52L1 and the upper end of the receiving frame 30L. The space formed by the port connection portion 52L and the receiving frame 30L is sealed except for the surface that communicates with the port 50L and the storage area 54LA located at the left end, which will be described later. The pit 52LP is stored within the receiving frame 30L. A control board 26L is placed on the port connection portion 52L. The control board 26L outputs an electrical signal to the speaker 62L in response to input from the player's operation of the keyboard 12.

[0025] The port connection portion 52L has multiple wiring clips 60. Each wiring clip 60 is a plate-like member having left and right main surfaces and protruding upward. A notch 60S is provided downward at the center upper end of each wiring clip 60 in the front-to-rear direction. More specifically, as shown in FIGS. 5 and 6(a), five wiring clips 60 are arranged at approximately equal intervals in the left-to-right direction in the center of the front-to-rear direction when viewed from above the port connection portion 52L. Three of the wiring clips 60 are located on the bottom surface 52LB. Two of the wiring clips 60 are located on the left and right sides of the top surface 52L1. Wiring (not shown) connecting the speaker 62L and the control board 26L (described later) is sandwiched in the notches 60S. This prevents the wiring from interfering with the upper case 14, the keyboard 12, and the like.

[0026] As shown in FIG. 6(b), the surrounding wall 64 protrudes downward from the outside of the bottom surface 52LB. More specifically, the surrounding wall 64 protrudes downward along the outer edges (right short side, front long side, and rear long side) of the bottom surface 52LB. Therefore, the surrounding wall 64 has a right wall portion 64RS, a front wall portion 64FS, and a rear wall portion 64BS, and is generally U-shaped when viewed from below, with an open left end. Elastic sealing material is attached to the lower ends of the right wall portion 64RS, the front wall portion 64FS, and the rear wall portion 64BS. The surrounding wall 64 is joined to a duct rib 68 to form a duct 58L. The duct 58L has a flat cylindrical shape extending in the left-right direction and is open at its left end. Specifically, the lower ends of the right wall portion 64RS, the front wall portion 64FS, and the rear wall portion 64BS are joined to the upper ends of the right rib 68R, the front rib 68F, and the rear rib 68B, respectively, to form the duct 58L. Thus, the duct 58L is configured by the surrounding wall 64 and the duct rib 68. In other words, the duct 58L is located below the lower ends (opening lower surfaces) of the storage section 54L and the acoustic section 56L, which will be described later. A portion of the duct 58L is formed by a part of the sound emitting member 28L1. A port 50L is located at the right end inside the duct 58L. In other words, the duct 58L has a port 50L that opens downward on the side opposite the side connected to the storage area 54LA, which will be described later. The duct 58L forms an enclosed space, excluding the port 50L and the opening at the left end.

[0027] The storage section 54L has a box shape with openings on the bottom and left sides. More specifically, when viewed from above, the storage section 54L has a substantially rectangular top surface 54L1 having a right short side, a front long side, and a rear long side. The top surface 54L1 has a right side surface 54L2, a front side surface 54L3, and a rear side surface 54L4 extending downward from each side of the top surface 54L1. The lower end of the right side surface 54L2 of the storage section 54L is connected to the left end of the top surface 52L1 of the port connection section 52L. The storage section 54L is placed on and fixed to the receiving frame 30L. More specifically, the lower ends of the front side surface 54L3 and the rear side surface 54L4 of the storage section 54L are joined to the upper end of the receiving frame 30L. Thus, a storage area 54LA is formed, surrounded by the top surface 54L1, right side surface 54L2, front side surface 54L3, rear side surface 54L4, and receiving frame 30L. An elastic sealant is attached to the joint surfaces between the lower ends of the front side surface 54L3 and the rear side surface 54L4 and the upper end of the receiving frame 30L. This seals the storage area 54LA, except for the surface at the right end that communicates with the duct 58L and the surface at the left end that communicates with the acoustic area 56LA (described later). The opening of the duct 58L is located near the lower right of the storage area 54LA. In other words, the left end of the duct 58L is connected to the storage area 54LA. Thus, the duct 58L connects the storage area 54LA to the port 50L. The storage area 54LA is connected to the outside of the lower case 16 via the duct 58L and the port 50L.

[0028] The storage section 54L stores a speaker 62L in a storage area 54LA. Therefore, by placing the storage section 54L on the receiving frame 30L, a storage space 54LS is formed to store the speaker 62L corresponding to the storage area 54LA. The speaker 62L is composed of a diaphragm 62L1, a magnet 62L2, and a voice coil (not shown). The diaphragm 62L1 is frustum-shaped with an upper surface, a lower surface, an inner surface, and an outer surface, and tapers from top to bottom. The upper surface of the diaphragm 62L1 is open and is defined by the boundary between the inner and outer surfaces. When viewed from above, the upper surface of the diaphragm 62L1 is a substantially elongated rectangle with the longitudinal direction extending left to right, and the left and right sides have arcs that bulge outward. The magnet 62L2 is flat and cylindrical with upper and lower surfaces that are perpendicular to the vertical direction. The upper surface of the magnet 62L2 is in contact with the lower surface of the diaphragm 62L1. When viewed from above, the center of the diaphragm 62L1 and the center of the magnet 62L2 overlap. The voice coil is located in the upper center of the magnet 62L2 so as to be embedded therein.

[0029] The inner surface of the diaphragm 62L1 is exposed from the top surface 54L1. Specifically, the open top surface of the diaphragm 62L1 is attached to a sound emission hole 54L1H that penetrates the top surface 54L1 in the vertical direction. The sound emission hole 54L1H has substantially the same shape as the top surface of the diaphragm 62L1, which will be described later. The bottom surface, inner surface, and outer surface of the diaphragm 62L1, which are located below the top surface, are located within the storage area 54LA. The speaker 62L receives an electrical signal from the control board 26L and emits sound upward from the diaphragm 62L1.

[0030] 6(a), a case fixing hole 48a that penetrates the storage section 54L in the vertical direction is provided at the rear of the lower side of the right side surface 54L2 of the storage section 54L. In other words, the case fixing hole 48a is located to the left of the mounting hole 40LB when viewed from above.

[0031] As shown in FIGS. 4 to 6, the acoustic unit 56L has a box shape with openings on the right and bottom sides. The rear left corner of the acoustic unit 56L is chamfered at approximately 45 degrees. More specifically, when viewed from above, the acoustic unit 56L has a substantially rectangular top surface 56L1 having a left short side, a front long side, and a rear long side, a left side surface 56L2 extending downward from the left short side, a front side surface 56L3 extending downward from the front long side, and a rear side surface 56L4 extending downward from the rear long side. An open right side surface is formed by the right ends of the top surface 56L1, the front side surface 56L3, and the rear side surface 56L4. This open right side surface is connected to the open left side surface of the storage unit 54L. Therefore, the top surface 54L1 and the top surface 56L1, the front side surface 54L3 and the front side surface 56L3, and the rear side surface 54L4 and the rear side surface 56L4 are all on the same plane.

[0032] The acoustic unit 56L is placed on and fixed to the receiving frame 30L. More specifically, the lower ends of the left side surface 56L2, front side surface 56L3, and rear side surface 56L4 are joined to the upper end of the receiving frame 30L. Therefore, as shown in FIG. 9, an acoustic area 56LA extending in the left-right direction is formed, surrounded by the upper surface 56L1, left side surface 56L2, front side surface 56L3, rear side surface 56L4, and receiving frame 30L. Therefore, by placing the acoustic unit 56L on the receiving frame 30L, an acoustic space 56LS corresponding to the acoustic area 56LA is formed. More specifically, the acoustic area 56LA includes the lower bosses 44b and 44c. The acoustic area 56LA is located on the left side of the generally truncated cone-shaped outer surface of the lower boss 44b that tapers upward, and on the left side of the outer surface of a truncated cone-shaped recess that tapers downward from the top surface 56L1 to surround the case fixing hole 48b. Elastic sealing material is attached to the joint surfaces between the lower ends of the left side surface 56L2, front side surface 56L3, and rear side surface 56L4 and the upper end of the receiving frame 30L. This seals the acoustic area 56LA tightly, except for the surface that communicates with the storage area 54LA located at the right end.

[0033] Thus, the acoustic region 56LA and the duct 58L are positioned symmetrically with respect to the storage region 54LA. The storage region 54LA and the acoustic region 56LA are connected to each other to form a single, interconnected space. This allows the acoustic region 56LA to communicate with the outside of the lower case 16 via the storage region 54LA, the duct 58L, and the port 50L. In other words, the port 50L communicates with the acoustic region 56LA via the duct 58L and the storage region 54LA. The low-frequency sounds emitted from the outer surface of the diaphragm 62L1 travel from the storage region 54LA to the acoustic region 56LA, as indicated by the dashed arrows in FIG. 9, and resonate in the acoustic region 56LA. Furthermore, the low-frequency sounds resonating in the acoustic region 56LA travel from the storage region 54LA to the duct 58L and are emitted downward from the port 50L. On the inner surface of the front side surface 56L3, rod-shaped ribs 66F1, 66F2, 66F3 extending from the upper end to the lower end along the vertical axis are disposed evenly in the left-right direction. On the inner surface of the rear side surface 56L4, rod-shaped ribs 66B1, 66B2, 66B3 extending from the upper end to the lower end along the vertical axis are disposed evenly in the left-right direction.

[0034] Four mounting holes 42LF, 42LB, 42RF, and 42RB are provided at the four corners of the acoustic unit 56L, penetrating the acoustic unit 56L in the vertical direction. The mounting holes 42LF, 42LB, 42RF, and 42RB are located at the front left corner, rear left corner, front right corner, and rear right corner of the acoustic unit 56L, respectively. Mounting screws 36 inserted from above into the mounting holes 42LF, 42LB, 42RF, and 42RB are threaded into vertical holes 34LF, 34LB, 34RF, and 34RB provided on the left side of the receiving frame 30L, which will be described later. This attaches the acoustic unit 56L to the receiving frame 30L. More specifically, the lower end of the acoustic unit 56L is joined to the upper end of the right side of the receiving frame 30L.

[0035] As shown in Figures 4 to 6, case fixing holes 48b and 48c are provided in the hollow truncated cone-shaped lower surface that tapers downward from the inside of the upper surface 56L1, penetrating this lower surface in the up-down direction. The case fixing holes 48b and 48c are located at the rear right and left sides of the acoustic unit 56L, respectively. More specifically, the case fixing holes 48b and 48c are located near the front left of the mounting hole 42RB and the front left of the mounting hole 42LB, respectively, when viewed from above.

[0036] Next, the operation and effect of the sound-emitting device 28L will be described. In the above configuration, when a player operates the keyboard 12, sound is emitted upward from the open upper surface of the diaphragm 62L1 of the speaker 62L, as indicated by the outline arrow in FIG. 9 . Simultaneously with this upward sound emission, low-pitched sounds are emitted from the outer surface of the diaphragm 62L1 of the speaker 62L, as indicated by the dashed arrow. These low-pitched sounds are transmitted to the acoustic area 56LA via the storage area 54LA. The low-pitched sounds then return to the storage area 54LA, pass through the duct 58L, and are emitted from the port 50L to the outside of the lower case 16. In this way, reinforced low-pitched sounds are emitted. The space formed between the lower main surface 16B2 of the lower case 16 and the mounting surface allows sound to be emitted without impeding air vibrations.

[0037] According to this embodiment, the acoustic area 56LA is located adjacent to the outer lateral side of the storage area 54LA that houses the speaker 62L, so the storage area 54LA does not need to have a volume required for the low-frequency resonance function. This allows the vertical length of the storage area 54LA to be kept to a length sufficient to house the speaker 62L. Furthermore, by adjusting the vertical length of the acoustic area 56LA to match the vertical length of the storage area 54LA and expanding it in the horizontal direction, the electronic keyboard instrument 1 can be made more compact. Specifically, the vertical length of the housing 10 can be reduced, resulting in a thinner design.

[0038] A resonance effect is generated by the configuration of the acoustic area 56LA, the duct 58L, and the port 50L. Specifically, when a performer operates the keyboard 12 and the speaker 62L emits sound upward, a low-pitched sound that resonates in the acoustic area 56LA is emitted downward from the port 50 via the storage area 54LA and the duct 58L, enhancing the resonance effect. The low-pitched sound emitted downward from the port 50 is in phase with the low-pitched sound emitted upward from the speaker 62L. This suppresses interference due to phase differences and reinforces the low-pitched sound. The sound-emitting device 28L can improve the bass reproduction capability while reducing the size (thinning) of the housing 10.

[0039] The acoustic area 56LA has sufficient capacity by expanding in the left-right direction. Furthermore, the storage area 54LA is interposed between the acoustic area 56LA and the port 50L, and the increased distance between the acoustic area 56LA and the port 50L increases the flow resistance from the acoustic area 56LA to the port 50L, increasing the elasticity of the air passing through the port 50L. This results in a favorable resonance effect and improves bass reproduction. Furthermore, the increased distance between the acoustic area 56LA and the port 50L increases the freedom to adjust the position of the port 50L according to the performance of the speaker 62L, resulting in better bass sound quality.

[0040] The lower bosses 44a and 44b provided within the receiving frame 30L are located near the vertical holes 32RB and 34LB at the rear end of the receiving frame 30L, avoiding the center of the receiving frame 30L in the front-to-rear direction. This prevents communication between the acoustic area 56LA and the storage area 54LA from being obstructed, allowing air vibrations to be transmitted smoothly between the acoustic area 56LA and the storage area 54LA. This improves bass reproduction.

[0041] In this way, the sound output device 28L can improve the bass reproduction capability while miniaturizing (thinning) the electronic keyboard instrument 1. The sound output device 28R also achieves the same functions and effects as the sound output device 28L. Furthermore, since the storage area 54LA does not have a bass resonance function, it is not affected by its position relative to the port 50L. The increased flexibility in the layout of the storage area 54LA allows the speaker 62L to be placed in a suitable position. This improves sound reproduction capability regardless of the bass.

[0042] The port connection portion 52L, the storage portion 54L, and the acoustic portion 56L are integrally molded to form the sound emitting member 28L1. The port connection portion 52L has an surrounding wall 64, and by placing the port connection portion 52L on the receiving frame 30L, the lower end of the surrounding wall 64 joins with the upper end of the duct rib 68 to form the duct 58L. In other words, the surrounding wall 64, which is part of the sound emitting member 28L1, forms part of the duct 58L. Furthermore, the duct 58L is formed by the surrounding wall 64, which is part of the sound emitting member 28L1, and the duct rib 68, which is part of the lower case 16. This allows for reduced manufacturing costs compared to forming the duct 58L using a separate plate-like member.

[0043] Furthermore, the lower bosses 44a, 44b, and 44c provided in the receiving frame 30L are aligned on the left-right axis Ax. This allows workers to easily insert the fixing screws 46 into the lower bosses 44a, 44b, and 44c during the process of integrating the upper case 14, the sound emitting member 28L1, and the lower case 16 with the fixing screws 46, improving work efficiency. This reduces manufacturing costs.

[0044] Furthermore, a plurality of U-shaped grooves 16B1d extending in the left-right direction are provided on the upper main surface 16B1 of the receiving frame 30L, which allows the air vibrations in the duct 58L toward the port 50L to be transmitted efficiently, improving bass reproduction capability.

[0045] On the inner surfaces of the front side surface 56L3 and the rear side surface 56L4 of the acoustic section 56L, rod-shaped ribs 66F1, 66F2, 66F3, 66B1, 66B2, 66B3 extending from the upper end to the lower end along the vertical axis are evenly arranged in the left-right direction. This increases the bending strength in the up-down direction even for the acoustic section 56L which is extended in the left-right direction, resulting in a stable resonance effect and improved bass reproduction capability.

[0046] The control board 26L is placed on the port connection portion 52L, which integrates the sound emitting device 28L and the control board 26L, improving the work efficiency in the assembly process of the electronic keyboard instrument 1 and reducing the manufacturing cost.

[0047] The port connection portion 52L and the acoustic portion 56L may be interchanged in their left and right positions relative to the storage portion 54L. The port connection portion 52R and the acoustic portion 56R may be interchanged in their left and right positions relative to the storage portion 54R.

[0048] The above-described embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. The embodiments and modifications of the present invention are included within the scope and spirit of the present invention, and are also included in the scope of the inventions and their equivalents as defined in the claims. [Explanation of symbols]

[0049] 1: Electronic keyboard instrument, 28L, 28R: Sound emitting device, 28L1, 28R1: Sound emitting member, 30L, 30R: Receiving frame, 52L, 52R: Port connection part, 54L, 54R: Storage part, 56L, 56R: Acoustic part

Claims

1. A box-shaped receiving frame with an opening at the top; an integrally molded sound emitting member placed on the receiving frame; Equipped with The sound emitting member and the receiving frame form a storage space for storing a speaker, an acoustic space connected to the storage space, and a duct connected to the storage space, the acoustic space is a space corresponding to an area including a plurality of lower bosses that fix the receiving frame and the sound emitting member and are arranged side by side in the left-right direction, The receiving frame is provided with a port that opens at a position corresponding to the duct. Sound emitting device.

2. the receiving frame has a plurality of vertical holes protruding upward and a plurality of lower bosses protruding upward therein; The upright holes are located at the front end and the rear end of the receiving frame so as to form a pair along the front-rear axis, and are arranged at a predetermined interval in the left-right direction, The lower boss is located near the upright hole so as not to come into contact with the longitudinal axis. The sound emitting device according to claim 1 .

3. The lower bosses are arranged at predetermined intervals along the same left-right axis. The sound emitting device according to claim 2 .

4. A part of the sound emitting member forms a part of the duct. The sound emitting device according to claim 1 .

5. The sound emitting member has a surrounding wall that protrudes downward, The receiving frame has a duct rib that protrudes upward, The duct is formed in the receiving frame by joining the lower end of the surrounding wall and the upper end of the duct rib. The sound emitting device according to claim 4.

6. A U-shaped groove extending in the left-right direction is provided on the upper main surface of the receiving frame. The sound emitting device according to claim 5 .

7. A control board that outputs an audio signal to the speaker is mounted and integrated. The sound emitting device according to claim 6.

8. a plurality of ribs extending from the upper end to the lower end are disposed on the inner surfaces of the front and rear sides of the box-shaped acoustic section that is placed on the receiving frame and that constitutes the acoustic area; The sound emitting device according to claim 7.

9. A sound emitting device according to any one of claims 1 to 8, Electronic keyboard instrument.

10. The duct is located inside the storage area, and the acoustic area is located outside the storage area.

10. The electronic keyboard instrument according to claim 9.

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