JP7803916B2 - Case Structure - Google Patents

Description

The present invention relates to a case structure.

Patent Document 1 discloses a speaker device having a speaker unit and a case that houses the speaker unit.

Japanese Patent Application Laid-Open No. 2006-304236

The case that houses the speaker unit is sometimes formed by combining multiple housings. In this case, there is a risk that the sound emitted from the speaker unit may leak through the gaps between the housings, affecting the sound perceived by the user.

Therefore, there is a need to provide a case structure that can suppress sound leakage from a case that houses a speaker unit.
In addition to such requirements, another objective of the present invention is to achieve actions and effects derived from the various configurations disclosed in the "Forms for Implementing the Invention" described below, which actions and effects cannot be obtained with conventional technologies.

The present invention provides
A case structure for a case that houses a speaker unit,
the case has a first housing and a second housing assembled to each other in a first direction;
In the first housing, a wall portion covering the speaker unit has a first opening portion that communicates the inside and outside of the wall portion and that extends to a joint surface with the second housing,
the second housing has a protruding wall that protrudes in the first direction so as to close the first opening when the second housing is assembled to the first housing,
a recessed groove into which the other peripheral edge portion is inserted is provided in one peripheral edge portion of the protruding wall and the first opening;
a third housing provided with a switch electrically connected to the speaker unit;
a region of the wall portion of the first housing that is located on an opposite side to the first opening in a second direction orthogonal to the first direction is shared with the third housing;
The case structure is configured such that a second opening is provided in the area of the wall portion shared with the third housing to allow access from the first opening side to the inside of the third housing .

The present invention provides a case structure that can suppress sound leakage from a case that houses a speaker unit.

FIG. 2 is a diagram illustrating a switch device. FIG. 10A and 10B are diagrams illustrating the arrangement of a speaker unit on the rear cover. FIG. 2 is a schematic cross-sectional view of the switch device. FIG. 2 is a schematic cross-sectional view of the switch device. FIG. FIG. 2 is a schematic cross-sectional view of a speaker unit. FIG. FIG. 2 is a schematic cross-sectional view of an upper case. FIG. 2 is a schematic cross-sectional view of an upper case. FIG. FIG. FIG. 10 is a diagram illustrating a protruding wall. 10A and 10B are diagrams illustrating the joining of the upper case and the lower case. FIG. 4 is a diagram illustrating sound pressure generated inside the case. FIG. 2 is a diagram illustrating a case structure. 10A and 10B are diagrams illustrating a case structure according to a modified example.

In this embodiment, a speaker unit 1 provided in a switch device 9 for a vehicle will be described by taking as an example a case in which the case structure 100 is adopted. The switch device 9 can be disposed, for example, on an instrument panel of the vehicle.
Fig. 1 is a diagram illustrating a switch device 9. Fig. 1 is a perspective view of the switch device 9 as seen from the user's side.
Fig. 2 is a diagram illustrating the switch device 9. Fig. 2 is an exploded perspective view of the switch device 9 as seen from the speaker unit 1 side. Note that in the enlarged view of Fig. 2, the lower case 5 of the speaker unit 1 is not shown, and only the upper case 4 is shown.
3A and 3B are diagrams illustrating the arrangement of the speaker unit 1 on the rear cover 92. Fig. 3A is a plan view schematically illustrating an enlarged view of the area of the upper case 4 where the speaker unit 1 is provided. Fig. 3B is a diagram illustrating the area around the upper case 4 before assembly, with the lower case 5, which is to be assembled to the upper case 4, positioned at a distance from the upper case 4.
Fig. 4 is a schematic cross-sectional view of the switch device 9. Fig. 4 shows a cross section of the switch device 9 taken along line AA in Fig. 3A, together with other components of the switch device 9.
Fig. 5 is a schematic cross-sectional view of the switch device 9. Fig. 5(A) is a schematic cross-sectional view of the speaker unit 1 taken along line A-A in Fig. 4. Fig. 5(B) is a schematic cross-sectional view of the speaker unit 1 taken along line B-B in Fig. 4.
4 and 5, the speaker units 2 are not shown, and the areas where the speaker units 2 are arranged are indicated by imaginary lines.

In the following explanation, when describing the positional relationships of the components of the speaker unit 1, the X, Y, and Z directions (see Figure 1, etc.) will be used as references. The X direction is the vehicle width direction, the Y direction is the vehicle front-to-rear direction, and the Z direction is the up-down direction, but they do not need to be completely parallel. Where necessary, the terms "vehicle front side" and "vehicle rear side" may be used with the Y direction as the reference. The terms "upper side" or "above" and "lower side" or "below" may be used with the Z direction as the reference.

As shown in FIG. 1, the switch device 9 includes multiple switches SW. The switches SW are used by the user to operate various in-vehicle devices such as the air conditioner, audio system, and car navigation system. The switches SW may be, for example, capacitive touch sensors.

The switch device 9 is equipped with a speaker unit 1 on its front side in the Y direction (second direction). When the switch device 9 is arranged on the instrument panel, the switch SW is exposed within the vehicle interior VR, while the speaker unit 1 is located in a position that is not exposed within the vehicle interior VR. When the switch SW is operated, the speaker unit 1 outputs an alarm sound or the like to notify the driver that the switch SW has been operated.

The switch device 9 has an operation panel 91 on which a switch SW is provided, and a rear cover 92 (third housing) connected to the operation panel 91 from the front side in the Y direction. The speaker unit 1 is provided on the rear cover 92 of the switch device 9.

As shown in FIG. 2, the switch device 9 has a basic configuration in which an intermediate case 93 and a printed circuit board 94 are housed between an operation panel 91 and a rear cover 92. In the switch device 9, the operation panel 91, intermediate case 93, printed circuit board 94, and rear cover 92 are arranged in this order in the assembly direction of the rear cover 92 to the operation panel 91 (Y direction in the figure).

As shown in FIG. 1, the operation panel 91 has marks Mk indicating the functions of the switches SW displayed on its surface 91a, which is exposed to the vehicle interior VR. Examples of marks Mk include those indicating air conditioning ON/OFF, outside air intake, inside air circulation, and seat heaters.

As shown in FIG. 2, six bolt bosses 911 (911a to 911f) are provided on the back surface 91b of the operation panel 91. The six bolt bosses 911 (911a to 911f) protrude away from the back surface 91b. The six bolt bosses 911 (911a to 911f) are spaced apart in the longitudinal direction (X direction) of the operation panel 91.

A sheet-like electrostatic sensor S is attached to the back surface 91b of the operation panel 91 (see Figure 4). The electrostatic sensor S has a sensor portion that corresponds one-to-one to each switch SW (see Figure 1) on the operation panel 91. The electrostatic sensor S is electrically connected to the connector portion C1 of the printed circuit board 94 via wiring Sa.

The intermediate case 93 has a band-shaped base 930 and a peripheral wall 932 that surrounds the entire outer periphery of the base 930. The base 930 is oriented along the X direction. When viewed from the Y direction, the base 930 has through holes 931 at positions that overlap with the bolt bosses 911 (911a to 911f) of the operation panel 91. The number of through holes 931 is the same as the number of bolt bosses 911.

When viewed from the intermediate case 93, a strip-shaped printed circuit board 94 is provided on the opposite side of the operation panel 91 in the Y direction. The printed circuit board 94 is oriented along the X direction. When viewed from the Y direction, the printed circuit board 94 has through holes 941 at positions that overlap the bolt bosses 911 of the operation panel 91 and the through holes 931 of the intermediate case 93. The number of through holes 931 is the same as the number of bolt bosses 911.

The printed circuit board 94 has three connectors C1, C2, and C3 on its surface 94b facing the rear cover 92 in the Y direction. The wiring Sa of the electrostatic sensor S is electrically connected to the connector C1. The wiring Sb (see Figure 6) of the speaker unit 2 (described below) is electrically connected to the connector C2. A power supply line (not shown) is electrically connected to the connector C3.

Although not shown in the figure, the printed circuit board 94 has a light-emitting element (LED) on its surface 94a facing the intermediate case 93 in the Y direction. The intermediate case 93 is provided with a lens that diffuses the light emitted from the light-emitting element. When viewed from the linear Y direction, the light-emitting element and lens are positioned so that they overlap the mark Mk (see Figure 1) of each switch SW on the operation panel 91. This allows the user to visually confirm whether the mark Mk of the operated switch SW is on or off.

As shown in FIG. 2, the rear cover 92 has a strip-shaped base 920. The rear cover 92 is provided with the base 920 oriented along the X direction. As shown in FIG. 4, the upper case 4, which is a component of the speaker unit 1, is provided in approximately the center of the base 920 in the X direction. The upper case 4 and the base 920 are integrally formed resin parts.

As shown in FIG. 2, six counterbore holes 921 (921a to 921f) are provided in the base 920 of the rear cover 92. The counterbore holes 921 (921a to 921f) are spaced apart in the X direction. The number of counterbore holes 921 (921a to 921f) is the same as the number of bolt bosses 911 described above.

In the rear cover 92, two countersunk holes 921a and 921b are located on one side (diagonally upper left side in Figure 2) when viewed from the upper case 4, and three countersunk holes 921d, 921e, and 921f are located on the other side (diagonally lower right side in Figure 2).
The countersunk hole 921c (second opening) is provided in an area overlapping with the upper case 4 when viewed from the Y direction.

As shown in Figure 4, when the rear cover 92 is attached to the operation panel 91, the intermediate case 93 and printed circuit board 94 are sandwiched between the rear cover 92 and the operation panel 91. In this state, the bolt boss 911 of the operation panel 91, the through hole 931 of the intermediate case 93, the through hole 941 of the printed circuit board 94, and the countersunk hole 921 of the rear cover 92 are arranged in an overlapping positional relationship.

As a result, by screwing the bolts B (Ba-Bf) inserted into the countersunk holes 921 in the rear cover 92 into the bolt bosses 911 on the operation panel 91 side, the housing of the switch device 9 is formed between the operation panel 91 and the rear cover 92, with the intermediate case 93 and printed circuit board 94 sandwiched between them.

FIG. 6 is an exploded perspective view of the speaker unit 1. As shown in FIG.
Fig. 7 is a schematic cross-sectional view of the speaker unit 1. Fig. 7A is a schematic cross-sectional view of the speaker unit 1 taken along line CC in Fig. 4. Fig. 7B is a schematic cross-sectional view of the speaker unit 1 taken along line AA in Fig. 7A.
8A and 8B are diagrams illustrating the upper case 4. Fig. 8A is a perspective view of the upper case 4 as viewed from below in the Z direction. In Fig. 8A, the connector C2 provided on the printed circuit board 94 is shown by imaginary lines. Fig. 8B is a plan view of the upper case 4 as viewed from the opening 45 side.
Fig. 9 is a schematic cross-sectional view of the upper case 4. Fig. 9 is a schematic cross-sectional view of the upper case 4 taken along line A-A in Fig. 8B.
Fig. 10 is a schematic cross-sectional view of the upper case 4. Fig. 10A is a schematic cross-sectional view of the upper case 4 taken along line A-A in Fig. 9A. Fig. 10B is a schematic cross-sectional view of the upper case 4 taken along line A-A in Fig. 10A. Fig. 10C is a schematic cross-sectional view of Fig. 10B with the lower case 5 superimposed thereon.

As shown in FIG. 6, the speaker unit 1 has a speaker unit 2 and a case 3 that houses the speaker unit 2. The case 3 has an upper case 4 (first housing) that is formed integrally with the rear cover 92, and a lower case 5 (second housing) that is detachably attached to the upper case 4.

The upper case 4 and lower case 5 are joined to each other along a line Lz (first direction) that runs along the Z direction, with the speaker unit 2 sandwiched between them. The speaker unit 2 is fixed to the upper case 4 with bolts B4. Furthermore, a line Ly that passes through the center of the countersunk hole 921c runs along the Y direction. The lines Lz and Ly are perpendicular to each other.

(Upper case 4)
As shown in FIG. 5 , the upper case 4 has a peripheral wall 41 (wall) that surrounds the outer periphery of the speaker unit 2 , and a bottom wall 42 that closes one opening of the peripheral wall 41 .
6, the peripheral wall 41 is provided with an opening oriented along the assembly direction (direction of the straight line Lz) of the upper case 4 and the lower case 5. Here, the assembly direction of the upper case 4 and the lower case 5 is a direction perpendicular to the assembly direction (direction of the straight line Ly) of the operation panel 91 and the rear cover 92.

As shown in FIG. 9 , the peripheral wall 41 has a generally rectangular shape surrounding the line Lz when viewed in the direction of the line Lz. The peripheral wall 41 is cylindrically formed from a pair of side walls 411, 412 spaced apart in the X direction (left-right direction in the figure), a connecting wall 413 connecting the distal ends of the side walls 411, 412, and a shared wall 414 connecting the proximal ends of the side walls 411, 412. The shared wall 414 is the area of the base 920 of the rear cover 92 that overlaps with the upper case 4.

In Figure 9, the line Lx is a line that runs along the X direction and passes through the midpoint between the pair of side wall portions 411 and 412. The line Ly is a line that runs along the Y direction and passes through the midpoint between the connecting wall portion 413 and the shared wall portion 414. The line Lz is a line that is perpendicular to the lines Lx and Ly.

The inside of the peripheral wall 41 is the accommodation space R for the speaker unit 2. A seat 43, which serves as the mounting surface for the speaker unit 2, is provided on the inside of the peripheral wall 41. The seat 43 is provided across the four corners of the approximately rectangular peripheral wall 41.

As shown in FIG. 9 , the pair of side wall portions 411, 412 are located on one side and the other side of the line Ly in the X direction. The side wall portions 411, 412 are formed in symmetrical shapes at symmetrical positions across the line Ly.

The side wall portions 411, 412 have recesses 416, 416 formed on the outer periphery at approximately the midpoint in the longitudinal direction (vertical direction in the figure). The recesses 416, 416 are grooves with a rectangular cross section that open to the outer periphery surfaces 411a, 412a of the side wall portions 411, 412.

As shown in Figure 5 (A), the recesses 416, 416 have lengths L416, L416 that extend to the lower ends of the side wall portions 411, 412 in the direction of the straight line Lz. The recesses 416, 416 have engagement protrusions 417, 417 located closer to the bottom wall portion 42 in the direction of the straight line Lz. As shown in Figure 9, the engagement protrusions 417, 417 are located closer to the connecting wall portion 413 (upper side in the figure) than to the direction of the straight line Lx.

As shown in FIG. 5B, the side wall portions 411 and 412 have step portions 415 and 415 at their lower ends in the direction of the straight line Lz.
The step portion 415 has a first lower end surface 415a (joint surface) and a second lower end surface 415b that are offset in the direction of the line Lz, and a step surface 415c that connects the first lower end surface 415a and the second lower end surface 415b. The first lower end surface 415a and the second lower end surface 415b are flat surfaces that are perpendicular to the line Lz. The step surface 415c is a flat surface that is parallel to the line Lz.

The first lower end surface 415a is connected to the outer peripheral surfaces 411a, 412a of the side wall portions 411, 412. The second lower end surface 415b is connected to the inner peripheral surfaces 411b, 412b of the side wall portions 411, 412. The second lower end surface 415b is located below the first lower end surface 415a in the direction of the straight line Lz.

As a result, when the lower case 5 is joined to the upper case 4, the first lower end surface 415a of the side wall portion 412 abuts against the lower case 5. Furthermore, the second lower end surface 415b overlaps the lower case 5 when viewed from the X direction. This creates a seal between the upper case 4 and the lower case 5 at their boundary, making it difficult for the storage space R surrounded by the upper case 4 and the lower case 5 to communicate with the outside in the X direction.

As shown in Figure 8, recesses 418, 418 are formed on the outer periphery of the connecting wall 413 where it connects to the side walls 411, 412. As shown in Figure 9, the recesses 418, 418 are grooves with a rectangular cross section that open to the outer periphery 411a, 412a of the side walls 411, 412 and the outer periphery 413a of the connecting wall 413. As shown in Figure 7A, the recesses 418, 418 have a length L418 in the direction of the straight line Lz, extending to the end 413c of the connecting wall 413 on the lower case 5 side. The recesses 418, 418 are provided with engagement protrusions 419, 419.

As shown in FIG. 9 , an opening 45 (first opening) is provided in the connecting wall portion 413 at approximately the center in the direction of the straight line Lx. The opening 45 penetrates the connecting wall portion 413 in the thickness direction (the up-down direction in the figure).

The boundary between the connecting wall portion 413 and the opening 45 is defined by peripheral portions 46, 47 with recessed grooves 6A, 6B. The peripheral portions 46, 47 have thicknesses W46, W47 in the direction of line Ly, and predetermined widths L46, L47 in the direction of line Lx (left-right direction in the figure).

As shown in (B) of Figure 8, the opening 45 is an area surrounded by a first side surface 451, which is the side surface of the peripheral portion 46 on the opening 45 side, a second side surface 452, which is the side surface of the peripheral portion 47 on the opening 45 side, and a third side surface 453 that connects the upper ends of the first side surface 451 and the second side surface 452.
The third side surface 453 is located above (upper side in the drawing) the bottom surface 42 a of the bottom wall portion 42 of the upper case 4 in the direction of the straight line Lz. Therefore, on the side of the third side surface 453 in the opening 45, the side surface 42 c of the bottom wall portion 42 is exposed.

As shown in the enlarged area of Figure 9, when viewed from the direction of line Lz, the first side 451 and second side 452 of the opening 45 are flat surfaces parallel to line Ly. The grooves 6A and 6B are recessed in directions away from each other at approximately the center of the first side 451 and second side 452 in the direction of line Ly. The distance W2 between the grooves 6A and 6B in the X direction is wider than the distance W1 between the first side 451 and second side 452 (W2 > W1, see Figure 8 (B)).

In this embodiment, grooves 6A and 6B are formed by utilizing the thickness of peripheral portions 46 and 47. Grooves 6A and 6B have shapes that are symmetrical across straight line Ly. In the following explanation, the shape of groove 6A will be described using groove 6A as an example.

The recessed groove 6A has a groove bottom 61 parallel to the straight line Ly and groove walls 62, 63 connecting both ends of the groove bottom 61 in the direction of the straight line Ly to the first side surface 451. The groove walls 62, 63 are perpendicular to the groove bottom 61.

In the recessed groove 6A, a rib 65 is provided on the groove wall 63 on the seating portion 43 side in the direction of the straight line Ly. The rib 65 has, for example, an arc shape with an apex 65a facing the groove wall 62 side.
In the recessed groove 6A, the groove width W65 of the region where the rib 65 is provided is narrower than the groove width W6 of the region where the rib 65 is not provided (W65<W6).

As shown in Figure 10 (A), in the direction of line Lz, the upper ends 6A1, 6B1 of the grooves 6A, 6B are connected to the third side surface 453 of the opening 45. The lower ends of the grooves 6A, 6B reach the lower end surfaces 46a, 47a of the peripheral portions 46, 47. In other words, the upper sides of the grooves 6A, 6B in the direction of line Lz are sealed by the bottom wall portion 42, and the lower ends open to the lower end surfaces 46a, 47a of the peripheral portions 46, 47.

The rib 65 is a linear protrusion that extends along the line Lz inside the grooves 6A and 6B. In the line Lz direction, the rib 65 is formed with a length that extends from the third side surface 453 of the opening 45 to near the lower end surfaces 46a and 47a of the peripheral portions 46 and 47.

10B, there is a region of height h65 where no rib 65 is provided on the lower end surface 47a side of the peripheral edge portion 47. In this region, the opening area of the recessed groove 6B on the lower end surface 47a side of the peripheral edge portion 47 is wider by the amount of the absence of the rib 65.
This makes it easier to insert a fitting wall 7B (see FIG. 10C ) of the lower case 5, which will be described later, into the recessed groove 6B than if the lower end 65c of the rib 65 were flush with the lower end surface 47a of the peripheral edge 47. Although not shown, the same applies to the rib 65 provided in the recessed groove 6A.

As shown in FIG. 8B, the common wall portion 414 of the peripheral wall portion 41 and the countersunk hole 921c are located on the rear side of the opening 45 in the direction of the straight line Ly.
In the opening 45, the distance W1 between the first side surface 451 and the second side surface 452 in the X direction is set to be wider than the hole diameter D1 of the countersunk hole 921c (W1>D1).

As shown in Figure 8 (A), the countersunk hole 921c of the rear cover 92 is provided in the shared wall portion 414. An opening window 923 is provided on the underside of the shared wall portion 414. The opening window 923 is connected to the countersunk hole 921c via a communication passage 924. When viewed from the direction of line Ly, the opening window 923 exposes the connector portion C2 (see the imaginary line in the figure) provided on the printed circuit board 94. The wiring Sb of the speaker unit 2 (see Figure 6) is connected to the connector portion C2 of the printed circuit board 94 from the opening window 923.

4, a boss 925 surrounding the countersunk hole 921c is provided on the common wall 414. The boss 925 protrudes in the direction of a straight line Ly from a surface 414a of the common wall 414 facing the printed circuit board 94.
Furthermore, the opposing surface 414 a of the common wall portion 414 is provided with engaging protrusions 928 , 928 on one side and the other side of the boss portion 925 in the X direction.

As shown in FIG. 4, a tool T (e.g., a screwdriver, hex wrench, etc.) is used to secure the rear cover 92 to the operation panel 91 using bolts B. The opening 45 in the connecting wall 413 is provided to ensure sufficient space for the tool T to access and tighten the bolts Bc housed in the countersunk holes 921c.

(Lower case 5)
11A and 11B are diagrams illustrating the lower case 5. Fig. 11A is a perspective view of the lower case 5 as seen from above in the Z direction. Fig. 11B is a plan view of the lower case 5.
Figure 12 is a diagram illustrating the lower case 5. Figure 12(A) is a schematic cross-sectional view taken along line A-A in Figure 11(B). Figure 12(B) is a view taken along line A-A in Figure 12(A). In Figure 12(B), cross-hatching is applied to the side wall portion 53 to make the shape easier to understand.
Fig. 13 is a diagram illustrating the protruding wall 533. Fig. 13 is a schematic cross-sectional view taken along line AA in Fig. 12(B).
14A and 14B are diagrams illustrating the joining of the upper case 4 and the lower case 5. Fig. 14A is a perspective view of the case 3 as seen from below in the Z direction. Fig. 14B is a view taken along the line A-A in Fig. 14A.

As shown in Figure 11 (A), the lower case 5 has a bottom wall portion 50 that is perpendicular to the line Lz, and a peripheral wall portion 55 that surrounds the outer periphery of the bottom wall portion 50. The peripheral wall portion 55 protrudes upward from the bottom wall portion 50 in the direction of the line Lz.

As shown in FIG. 11B, the bottom wall 50 has a mesh-like grill portion 502 in which a plurality of through holes 501 are formed, and a frame portion 503 surrounding the outer periphery of the grill portion 502 .
As shown in FIG. 12A, in the bottom wall portion 50, the upper surface 502a of the grill portion 502 is slightly offset downward in the direction of the straight line Lz from the upper surface 503a of the frame portion 503.

As shown in Figure 11 (B), the peripheral wall portion 55 has side walls 51 and 52 that face each other in the X direction, sandwiching the grill portion 502 therebetween, and side walls 53 and 54 that face each other in the Y direction, sandwiching the grill portion 502 therebetween.

As shown in FIG. 12A, the side wall portion 51 has a base portion 510 connected to the bottom wall portion 50. The base portion 510 is provided over the entire length of the bottom wall portion 50 in the Y direction. A protruding wall 511 protruding upward in the direction of the straight line Lz is provided on the upper surface 510a (joint surface) of the base portion 510. The protruding wall 511 is provided with an engagement hole 511a that penetrates the protruding wall 511. Note that, as shown in FIG. 11A, the side wall portion 52 has a shape symmetrical to the side wall portion 51 with the grill portion 502 in between. The side wall portion 52 also has a base portion 520 connected to the bottom wall portion 50 and a protruding wall 521 that protrudes from the base portion 520. An engagement hole 521a penetrates the protruding wall 521.

As shown in Figure 11 (A), the side wall portion 54 has a notch 545 formed in the center in the X direction. The notch 545 is provided over the entire length of the side wall portion 54 in the direction of the straight line Lz. The side wall portion 54 has engagement holes 54a, 54a that penetrate the side wall portion 54 on the side of the side wall portion 51 and the side wall portion 52 that are sandwiched between the notch 545.

As shown in Figure 11 (B), in the X direction, the notch width W545 of the notch 545 is wider than the width W925 of the boss portion 925 (see Figure 7 (B)) provided on the rear cover 92 (W545 > W925).

As shown in Figure 12 (A), a lid portion 56 is provided below the side wall portion 54 across the bottom wall portion 50 in the direction of straight line Lz. As shown in Figure 12 (B), the lid portion 56 is provided over the entire length of the bottom wall portion 50 in the X direction.

As shown in Figures 11A and 11B, the side wall portion 53 is composed of three walls spaced apart in the X direction. Specifically, it has a protruding wall 531 connected to the side wall portion 51, a protruding wall 532 connected to the side wall portion 52, and a protruding wall 533 disposed between the protruding walls 531 and 532. As shown in Figure 12B, the protruding walls 531 and 532 are provided with engagement holes 531a and 532a that penetrate the protruding walls 531 and 532, respectively.

As shown in FIG. 12B, in the X direction, there are provided gaps CL1, CL1 between the protruding wall 533 and the protruding walls 531, 532.
The protruding walls 531, 532 and the protruding wall 533 are connected via connecting walls 536, 537, respectively. Upper surfaces 536a, 537a of the connecting walls 536, 537 are positioned slightly above an upper surface 503a of the frame portion 503 of the bottom wall portion 50.

In Figure 11 (B), cross-hatching is applied to the upper surfaces 510a, 520a of the bases 510, 520 of the side wall portions 51, 52 and the upper surfaces 536a, 537a of the connecting walls 536, 537. These upper surfaces 510a, 520a, 536a, 537a are flat surfaces perpendicular to the line Lz and form the joint surfaces with the upper case 4.

As shown in Figure 12 (B), the protruding wall 533 has a first side surface 533b and a second side surface 533c that extend along the line Lz, and a third side surface 533a that connects the upper ends of the first side surface 533b and the second side surface 533c in the line Lz.

In the X direction, the width W3 from the first side surface 533b to the second side surface 533c is approximately equal to the opening width W1 of the opening 45 of the upper case 4 (see FIG. 8B) (W3 ≒ W1). In addition, in the Z direction, the height H533 from the upper surfaces 536a, 537a of the connecting walls 536, 537 to the third side surface 533a is approximately equal to the groove length L6 of the recessed grooves 6A, 6B in the direction of the straight line Lz (see FIG. 10B) (H533 ≒ L6). In other words, the protruding wall 533 has an area that is approximately equal to the opening area of the opening 45 of the upper case 4. As a result, when the lower case 5 is joined to the upper case 4, the opening 45 is closed by the protruding wall 533 (see FIG. 14A). That is, the protruding wall 533 protrudes in the direction of the straight line Lz so as to block the opening 45 when the lower case 5 is assembled to the upper case 4.

Here, as shown in the enlarged area of Figure 12(A), a step portion 535 is provided at the upper end of the protruding wall 533 by cutting away part of the protruding wall 533. Specifically, the step portion 535 has a first step surface 535a connected to the third side surface 533a, and a second step surface 535b connecting the first step surface 535a to the inner circumferential surface 533d. The first step surface 535a is a flat surface parallel to the straight line Lz. The second step surface 535b is a flat surface perpendicular to the straight line Lz.

When the opening 45 is closed by the protruding wall 533, the third side surface 533a of the protruding wall 533 faces the third side surface 453 of the opening 45 in the direction of the straight line Lz. The second step surface 535b of the step portion 535 faces the bottom surface 42a of the bottom wall portion 42. Furthermore, in the Y direction, the first step surface 535a of the step portion 535 faces the side surface 42c of the bottom wall portion 42. This creates a sealed structure at the boundary between the bottom wall portion 42 and the protruding wall 533. Therefore, the storage space R surrounded by the upper case 4 and lower case 5 is less likely to communicate with the outside in the Y direction (see Figure 10 (C)).

(Fitting walls 7A, 7B)
As shown in FIG. 12B, the first side surface 533b and the second side surface 533c of the protruding wall 533 are provided with fitting walls 7A and 7B that protrude in directions that separate from each other in the X direction.
The fitting walls 7A and 7B are continuous walls that are provided linearly over the entire length of the protruding wall 533 in the direction of the straight line Lz, and are provided in a range that spans from the third side surface 533a of the protruding wall 533 to the connecting walls 536 and 537. These fitting walls 7A and 7B constitute the peripheral portion of the protruding wall 533 in the present invention.

In the X direction, the width W4 from mating wall 7A to mating wall 7B is approximately equal to the width W2 from groove 6A to groove 6B of the upper case 4 (see Figure 8(B)) (W4 ≒ W2).

As shown in FIG. 13, the fitting walls 7A and 7B are provided between the inner peripheral surface 533d and the outer peripheral surface 533e of the protruding wall 533 in the Y direction.
The fitting wall 7A has side surfaces 71 and 72 that are perpendicular to the first side surface 533b of the protruding wall 533 and an end surface 73 that connects the tips of the side surfaces 71 and 72 in the X direction. The fitting wall 7B has side surfaces 71 and 72 that are perpendicular to the second side surface 533c of the protruding wall 533 and an end surface 73 that connects the tips of the side surfaces 71 and 72 in the X direction.

As shown in the enlarged area of Figure 13, the thickness T7 of the mating walls 7A, 7B in the Y direction is approximately equal to the groove width W65 of the region where the rib 65 (see phantom lines in the figure) is provided in the aforementioned grooves 6A, 6B (T7 ≈ W65). Furthermore, the protrusion lengths L7 of the mating walls 7A, 7B from the first side surface 533b and the second side surface 533c in the X direction are set to be shorter than the groove depth D6 of the grooves 6A, 6B, respectively (L7 < D6). As a result, the mating walls 7A, 7B are in surface contact with the groove walls 62 of the grooves 6A, 6B at their side surfaces 71, and in line contact with the rib 65 at their side surfaces 72.

As shown in Figure 14(A), when the lower case 5 is assembled to the upper case 4 to form the case 3, the engagement hole 521a provided in the side wall portion 52 of the lower case 5 engages with the engagement protrusion 417 on the side wall portion 412 of the upper case 4. The engagement holes 531a, 532a provided in the side wall portion 53 of the lower case 5 engage with the engagement protrusions 419, 419 on the connecting wall portion 413 of the upper case 4. As shown in Figure 14(B), the engagement holes 54a, 54a provided in the side wall portion 54 engage with the engagement protrusions 928, 928 provided on the shared wall portion 414. In addition, the engagement hole 511a (see Figure 12(A)) provided in the side wall portion 51 of the lower case 5 engages with the engagement protrusion 417 (see Figure 5(A)) on the side wall portion 411 of the upper case 4. The opening window 923 in the rear cover 92 is covered by the lid portion 56 of the lower case 5.

Also, as shown in FIG. 5B, the upper surface 510a of the base 510 of the lower case 5 and the upper surface 520a of the base 520 abut against the first lower end surfaces 415a, 415a of the side wall portions 411, 412 of the upper case 4, respectively. Furthermore, the upper surfaces 536a, 537a (see FIG. 12B) of the connecting walls 536, 537 of the lower case 5 abut against the lower end surfaces 46a, 47a (see FIG. 8B) of the peripheral portions 46, 47.

That is, the first lower end surfaces 415a, 415a (see FIG. 8A) and lower end surfaces 46a, 47a (see FIG. 8B) of the peripheral edges 46, 47 of the upper case 4, and the upper surfaces 510a, 520a, 536a, 537a (see FIG. 11B) of the lower case 5 constitute the joining surfaces in this application.

Furthermore, as shown in Figure 5(B), when viewed from the X direction, the second lower end surfaces 415b, 415b of the side wall portions 411, 412 of the upper case 4 overlap the base portions 510, 520 of the lower case 5.

In this embodiment, as shown in Figure 10(C), the opening 45 of the upper case 4 is blocked by inserting the protruding wall 533 of the lower case 5 from below in the Z direction. The mating wall 7B (see dashed line in the figure) is inserted into the recessed groove 6B from the lower end surface 47a of the peripheral portion 47, moves upward in the Z direction, and ultimately faces the third side surface 453 of the opening 45 with a small gap between them.

In this state, as shown in Figure 16, when viewed from the Y direction, the peripheral edges 46 and 47 of the opening 45 overlap with the mating walls 7A and 7B, which are the peripheral edges of the protruding wall 533.

Also, as shown in Figure 12 (A), when viewed from the Y direction, the first step surface 535a of the protruding wall 533 overlaps the step surface 42b of the bottom wall portion 42 of the upper case 4.

As a result, when the case 3 is viewed from the X and Y directions, which are perpendicular to the joining direction (Z direction), the areas around the joint between the upper case 4 and the lower case 5 overlap each other. This ensures that the storage space R of the case 3 is sealed.

(Case structure 100)
Fig. 15 is a diagram for explaining the sound pressure generated in the case 3. Fig. 15 is a schematic cross-sectional view of the speaker unit 1 of Fig. 14(A) taken along plane B.
16 is a diagram illustrating the case structure 100. FIG. 16 is a schematic cross-sectional view taken along line AA in FIG.

As shown in FIG. 15 , in the speaker section 1, the speaker unit 2 is housed in the housing space R surrounded by the upper case 4 and the lower case 5. The speaker unit 2 is housed in the housing space R with the front-to-rear direction of the speaker unit 2 oriented along the line Lz. The speaker unit 2 has a drive unit 20 that generates sound and a support unit 21 that supports the drive unit 20. The speaker unit 2 is housed in the housing space R between the upper case 4 and the lower case 5 with the diaphragm 201 (cone paper) of the drive unit 20 that forms the front surface facing downward in the line Lz. Wiring Sb is connected to the drive unit 20 of the speaker unit 2. Wiring Sb is electrically connected to the connector portion C2 provided on the printed circuit board 94.

As shown in FIG. 6 , the support portion 21 of the speaker unit 2 has a flange portion 210 that surrounds the outer peripheral edge of the diaphragm 201. A through-hole 211 penetrates the flange portion 210 in the direction of the straight line Lz. The speaker unit 2 is fixed to the upper case 4 by screwing a bolt B4 that passes through the through-hole 211 while the flange portion 210 is seated on the seat portion 43 of the upper case 4.

As shown in Figure 15, when the upper case 4 and lower case 5 are joined, the flange portion 210 of the speaker unit 2 abuts against the frame portion 503 of the bottom wall portion 50 of the lower case 5 in the direction of the straight line Lz. The diaphragm 201 of the speaker unit 2 faces the grill portion 502 with a gap between them. The speaker unit 2 is arranged so that all parts other than the flange portion 210 are spaced apart from the upper case 4 and lower case 5 with a gap between them.

When the diaphragm 201 vibrates in response to driving of the driver 20 of the speaker unit 2, a positive-phase sound pressure Sp is generated toward the front side of the diaphragm 201 (the lower side in the direction of the straight line Lz), and an opposite-phase sound pressure Sp' is generated toward the rear side of the diaphragm 201 (the upper side in the direction of the straight line Lz). The positive-phase sound pressure Sp and the opposite-phase sound pressure Sp' each spread spherically from the diaphragm 201. In this embodiment, with the abutment surface P between the flange portion 210 and the lower case 5 as the boundary, the area below the abutment surface P in the direction of the straight line Lz is the area from which the positive-phase sound pressure Sp is generated, and the area above the abutment surface P is the area from which the opposite-phase sound pressure Sp' is generated.
Therefore, as shown in FIG. 16, when viewed from the direction of the straight line Lz, the sound pressure Sp' of the opposite phase acts on substantially the entire surface of the peripheral wall portion 41 of the upper case 4.

Of the peripheral wall portion 41, the side wall portions 411, 412 and the shared wall portion 414 are continuous walls formed integrally with the rear cover 92 and therefore have high rigidity. Therefore, they are little affected by the action of the opposite-phase sound pressure Sp'. On the other hand, in this embodiment, to ensure work space, an opening 45 is provided in the connecting wall portion 413 of the peripheral wall portion 41, and this opening 45 is closed by the protruding wall 533 of the lower case 5. Because the protruding wall 533 is separate from the rear cover 92, it has lower rigidity than the side wall portions 411, 412 and the shared wall portion 414 of the peripheral wall portion 41. Therefore, they are easily affected by the action of the opposite-phase sound pressure Sp' on the protruding wall 533.

When the sound pressure Sp' acts on the protruding wall 533, the protruding wall 533 is displaced away from the speaker unit 2, forming a gap between the protruding wall 533 and the opening 45, which may result in sound leakage. The sound leaking from the gap between the protruding wall 533 and the opening 45 is an antiphase sound, which weakens the positive phase sound. Furthermore, if the antiphase sound is perceived by the user, it will cause the user to feel uncomfortable. Furthermore, when the sound pressure Sp' acts on the protruding wall 533, the protruding wall 533 vibrates in the direction in which the sound pressure Sp' acts. If the vibration of the protruding wall 533 propagates throughout the case 3, chatter may occur in the case 3. The chattering sound of the case 3 also causes the user to feel uncomfortable.
In contrast to these problems, for example, if the connecting wall 413 is formed as a continuous wall with the side walls 411 and 412 without providing the opening 45, the rigidity and strength against the sound pressure Sp' is ensured, thereby suppressing sound leakage and chatter. However, this would result in a loss of working space for threading the bolts Bc (see FIG. 4), which would lead to a deterioration in the ease of assembling the rear cover 92.

Therefore, in this embodiment, the case structure 100 is provided with the recessed grooves 6A, 6B and the fitting walls 7A, 7B that fit together in the opening 45 and the protruding wall 533.
16 , when an out-of-phase sound pressure Sp′ acts on the inner peripheral surface 533d of the protruding wall 533, pushing the protruding wall 533 in the Y direction away from the speaker unit 2 (indicated by the black arrow in the enlarged area of FIG. 16 ), the side surfaces 71, 71 of the fitting walls 7A, 7B are pressed against the groove walls 62, 62 of the recessed grooves 6A, 6B, respectively. At this time, a reaction force acts on the side surfaces 71, 71 of the fitting walls 7A, 7B from the groove walls 62, 62 of the recessed grooves 6A, 6B, respectively (indicated by the white arrow in the enlarged area of FIG. 16 ).

As a result, the pressing force due to the sound pressure Sp' and the reaction force from the recessed grooves 6A and 6B are balanced, reducing the displacement of the protruding wall 533 away from the speaker unit 2. Therefore, the case structure 100 according to this embodiment can ensure working space, suppress sound leakage, and reduce chatter.

Furthermore, in the case structure 100 according to this embodiment, ribs 65 are provided on the groove wall 63 side of the grooves 6A and 6B. This allows the side surfaces 72 and 72 of the mating walls 7A and 7B to also abut against the ribs 65. As a result, the mating walls 7A and 7B are supported by the grooves 6A and 6B from both sides in the Y direction. This reduces rattling of the mating walls 7A and 7B within the grooves 6A and 6B in response to changes in sound pressure Sp'.

In this case, it is also possible to simply reduce the spacing W6 (see Figure 9) between the groove walls 62, 63 without providing the rib 65. However, the mating walls 7A, 7B would be in surface contact with both the groove walls 62, 63 of the grooves 6A, 6B. This would increase resistance when inserting the mating walls 7A, 7B into the grooves 6A, 6B, affecting workability. Therefore, by providing a rib 65 that narrows the spacing between the groove walls 62, 63, as in the present application, the sides of the mating walls 7A, 7B that come into contact with the rib 65 are in line contact, reducing resistance during insertion. This allows the mating walls 7A, 7B to be inserted into the grooves 6A, 6B with less force, improving workability.

As described above, the case structure 100 according to this embodiment has the following configuration.
(1) The case structure 100 of the case 3 that houses the speaker unit 2.
The case 3 has an upper case 4 (first housing) and a lower case 5 (second housing) that are assembled together in the direction of a straight line Lz (first direction).
In the upper case 4, an opening 45 (first opening) that connects the inside and outside of the peripheral wall portion 41 (wall portion) covering the speaker unit 2 is formed, extending to the lower end surfaces 46a, 47a of the peripheral portions 46, 47, which are the joint surfaces with the lower case 5.
The lower case 5 has a protruding wall 533 that protrudes in the direction of the straight line Lz so as to close the opening 45 when the lower case 5 is assembled to the upper case 4 .
When the opening 45 is viewed from the direction of the straight line Ly (second direction) perpendicular to the direction of the straight line Lz, the mating walls 7A and 7B, which are the peripheral portions of the protruding wall 533, and the peripheral portions 46 and 47, which are the peripheral portions of the opening 45 in the peripheral wall portion 41, overlap.
The peripheral edges 46, 47 (one peripheral edge) of the opening 45 are provided with recessed grooves 6A, 6B into which the fitting walls 7A, 7B (the other peripheral edge) of the protruding wall 533 are inserted.

The sound pressures Sp and Sp' generated by the speaker unit 2 spread spherically. Therefore, the sound pressures Sp and Sp' also act on the upper case 4. If an opening 45 is formed in the peripheral wall 41 that covers the speaker unit 2, simply blocking the opening 45 with the protruding wall 533 may result in a gap between the protruding wall 533 and the opening 45 when the sound pressures Sp and Sp' (especially the sound pressure Sp') act, potentially causing sound leakage. Furthermore, the sound pressure Sp' may cause the protruding wall 533 to vibrate, resulting in chatter in the case 3 itself, making it impossible to ensure the required sound pressure.
Therefore, with the above configuration, even if sound pressure acts on the protruding wall 533, the fitting walls 7A and 7B are fitted into the recessed grooves 6A and 6B, so that a reaction force in a direction that resists the sound pressure Sp' is generated in the protruding wall 533. As a result, vibration of the protruding wall 533 is suppressed, and a gap is less likely to occur between the protruding wall 533 and the opening 45. This keeps the opening 45 closed by the protruding wall 533, thereby suppressing sound leakage and chattering of the case 3.

The case structure 100 according to this embodiment has the following configuration.
In the above (1),
(2) The grooves 6A and 6B are provided with ribs 65, 65 that narrow the groove width W6 of the grooves 6A and 6B.

With this configuration, it is possible to reduce rattling of the protruding wall 533 within the recessed grooves 6A and 6B.
It is also possible to simply reduce the groove width W6 (see FIG. 9 ) without providing the rib 65. However, the fitting walls 7A, 7B would be in surface contact with both the groove walls 62, 63 of the recessed grooves 6A, 6B. This would increase the resistance when inserting the fitting walls 7A, 7B into the recessed grooves 6A, 6B, affecting the ease of assembly of the lower case 5 to the upper case 4.
Therefore, by configuring as described above and providing ribs 65 in the recessed grooves 6A and 6B, the side of the protruding wall 533 that comes into contact with the ribs 65 is in line contact, which reduces resistance during insertion and improves workability.

The case structure 100 according to this embodiment has the following configuration.
In the above (1) or (2),
(3) The direction of the straight line Lz is along the front-rear direction of the speaker unit 2 .
The lower case 5 is attached to the upper case 4 from the diaphragm 201 side (front side) of the speaker unit 2 in the direction of the straight line Lz.
The opening 45 and the protruding wall 533 are arranged at least on the opposite phase side of the sound emitted from the speaker unit 2 .

In the spherically spreading sound pressures Sp, Sp', if sound having anti-phase sound pressure Sp' leaks to the outside and interferes with the positive phase sound pressure Sp, it may affect the sound perceived by the user.
Therefore, by configuring as described above, it is possible to reduce the leakage of sound having the opposite phase sound pressure Sp' to the outside of the case 3, thereby reducing the influence on the sound perceived by the user.

The case structure 100 according to this embodiment has the following configuration.
In any one of the above (1) to (3),
(4) When viewed from the direction of the straight line Ly, the recessed grooves 6A and 6B are located on both sides of the opening 45 in the X direction (width direction).

This configuration improves the support stability of the protruding wall 533 against sound pressures Sp and Sp'.

The case structure 100 according to this embodiment has the following configuration.
In any one of the above (1) to (4),
(5) A rear cover 92 (third housing) is provided with a switch device 9 electrically connected to the speaker unit 2,
The peripheral wall portion 41 of the upper case 4 shares an area located on the opposite side of the opening 45 in the direction of the straight line Ly with the rear cover 92 .
A common wall portion 414, which is an area of the peripheral wall portion 41 shared with the rear cover 92, is provided with a countersunk hole 921c (second opening) for accessing the inside of the rear cover 92 from the opening 45 side.

With this configuration, when assembling the switch device 9, the opening 45 can be used as a working space for accessing the counterbore 921c.
This allows the switch device 9 to achieve both improved workability and reduced sound leakage.

(Modification)
FIG. 17 is a diagram illustrating a case structure 100A according to a modified example.
In the present embodiment, the recessed grooves 6A and 6B are provided on the periphery of the opening 45 of the upper case 4, and the fitting walls 7A and 7B are provided on the periphery of the protruding wall 533 of the lower case 5. However, the present invention is not limited to this.

17, mating walls 7A', 7B' may be provided on the opening 45A side of the upper case 4A, and recessed grooves 6A', 6B' may be provided on the protruding wall 533A side of the lower case 5A. In a case structure 100A according to a modified example, ribs 75, 75 are provided on side surfaces 72', 72' of the mating walls 7A', 7B'.
That is, in the case structure 100A according to the modified example, the fitting walls 7A' and 7B' form the peripheral edge of the opening 45A. Also, the area of the protruding wall 533A surrounding the recessed grooves 6A' and 6B' forms the peripheral edge of the protruding wall 533A.

In this case, an out-of-phase sound pressure Sp' acts on the inner surface 533d of the protruding wall 533A, pushing the protruding wall 533A away from the speaker unit 2 in the Y direction (shown by the black arrow in the enlarged area of Figure 17). This causes the groove walls 63', 63' of the recessed grooves 6A', 6B' to press against the side surfaces 71', 71' of the mating walls 7A', 7B', respectively. At this time, a reaction force acts on the groove walls 63', 63' of the recessed grooves 6A', 6B' from the side surfaces 71', 71' of the mating walls 7A', 7B' (shown by the white arrow in the enlarged area of Figure 17).

As a result, the pressing force due to the sound pressure Sp' and the reaction force from the fitting walls 7A' and 7B' are balanced, reducing the displacement of the protruding wall 533A away from the speaker unit 2.

As described above, the case structure 100A according to the modified example has the following configuration.
(I) A case structure 100A of the case 3 that houses the speaker unit 2.
The case 3A has an upper case 4A (first housing) and a lower case 5A (second housing) that are assembled together in the direction of a straight line Lz (first direction).
In the upper case 4A, an opening 45A (first opening) that connects the inside and outside of the peripheral wall portion 41A (wall portion) covering the speaker unit 2 is formed in the peripheral wall portion 41A, extending to the lower end surfaces 46a, 47a of the peripheral portions 46, 47, which are the joint surfaces with the lower case 5A.
The lower case 5A has a protruding wall 533A that protrudes in the direction of the straight line Lz so as to close the opening 45A when the lower case 5A is assembled to the upper case 4A.
When the opening 45A is viewed from the direction of the line Ly (second direction) perpendicular to the direction of the line Lz, the mating walls 7A', 7B' which form the peripheral portion of the opening 45A and the recessed grooves 6A', 6B' which form the peripheral portion of the protruding wall 533A overlap.
The fitting walls 7A' and 7B' of the opening 45A form one of the peripheral edges.
The area of the protruding wall 533A surrounding the recessed grooves 6A' and 6B' constitutes the other peripheral edge portion into which the fitting walls 7A' and 7B' are inserted.

This configuration also makes it possible to secure work space while suppressing sound leakage.

The above describes embodiments and variations of the present invention, but the present invention is not limited to these and can be modified as appropriate within the scope of the technical concept of the invention.

REFERENCE SIGNS LIST 1 Speaker section 2 Speaker unit 3 Case 4 Upper case 5 Lower case 6A, 6B Groove 7A, 7B Fitting wall (periphery)
9 Switch device 41 Peripheral wall portion (wall portion)
45 Opening (first opening)
46 Peripheral edge portion 46a Lower end surface (joint surface)
47 Peripheral edge portion 47a Lower end surface (joint surface)
65 Rib 91 Operation panel 92 Rear cover (third housing)
100 Case structure 413 Connection wall portion 414 Shared wall portion (area in the wall portion shared with the third housing)
533 Protruding wall 921c Counterbore hole (second opening)
Bc Volts Sp Sound pressure in positive phase Sp' Sound pressure in negative phase Lx Line Ly Line (second direction)
Lz Straight line (first direction)

Claims (4)

A case structure for a case that houses a speaker unit,
the case has a first housing and a second housing assembled to each other in a first direction;
In the first housing, a wall portion covering the speaker unit has a first opening portion that communicates the inside and outside of the wall portion and that extends to a joint surface with the second housing,
the second housing has a protruding wall that protrudes in the first direction so as to close the first opening when the second housing is assembled to the first housing,
a recessed groove into which the other peripheral edge portion is inserted is provided in one peripheral edge portion of the protruding wall and the first opening;
a third housing provided with a switch electrically connected to the speaker unit;
a region of the wall portion of the first housing that is located on an opposite side to the first opening in a second direction orthogonal to the first direction is shared with the third housing;
A case structure characterized in that a second opening is provided in an area of the wall portion shared with the third housing, for accessing the inside of the third housing from the side of the first opening . In claim 1,
A case structure characterized in that the groove is provided with a rib that narrows the groove width of the groove. In claim 1,
the first direction is a direction along a front-rear direction of the speaker unit,
the second housing is attached to the first housing from the front side of the speaker unit,
A case structure characterized in that the first opening and the protruding wall are arranged at least on the opposite phase side of the sound emitted from the speaker unit. In claim 1,
A case structure characterized in that, when viewed from a second direction perpendicular to the first direction, the recessed grooves are located on both sides of the first opening in the width direction.