Air pressure balance hole channel structure and electronic equipment

Abstract

The utility model belongs to the technical field of electronic equipment, and particularly relates to an air pressure balance hole channel structure and electronic equipment. The air pressure balance hole channel structure comprises a waterproof breathable film, a shell and a structural part installed in the shell, a communication hole communicated with the outside is formed in the shell, a balance hole, a balance channel and a supporting table are arranged on the structural part, and the balance hole is communicated between the communication hole and the balance channel; the supporting table is arranged in the balance channel, the waterproof breathable film is sealed in the balance hole, and the top face of the supporting table supports the waterproof breathable film. The waterproof breathable film is supported by the top face of the supporting table arranged in the balance channel, so that the situation that the air pressure balance hole channel structure loses efficacy due to the fact that the waterproof breathable film deforms under the action of external force in the height direction to block the balance channel is avoided, and the stability of the air pressure balance hole channel structure during working is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of electronic equipment, and particularly relates to an air pressure balance hole channel structure and electronic equipment. Background Art

[0002] For electronic devices with waterproof performance, such as waterproof mobile phones, waterproof watches, etc., the inside of the outer casing of the electronic device is a closed space. When the speaker or receiver of the electronic device is working, the air flow in the closed space vibrates, causing an imbalance in the air pressure inside and outside the electronic device, which in turn makes the electronic device prone to noise.

[0003] In order to solve the above problems, an air pressure balance hole channel structure is provided on an electronic device of the related art. The electronic device includes a structural member and a battery cover covering the bottom side of the structural member. The air pressure balance hole channel structure includes a waterproof breathable membrane, a connecting hole, a balance hole and a balance channel. The connecting hole is provided on the battery cover, and the balance channel and the balance hole are provided at positions corresponding to the connecting hole on the structural member. The balance hole connects the balance channel and the connecting hole, and the waterproof breathable membrane is sealed in the balance hole. When the speaker or receiver of the electronic device is working, the external airflow can flow in the balance channel after passing through the waterproof breathable membrane, and the airflow in the electronic device can also flow out through the waterproof breathable membrane after passing through the balance channel, so that the internal and external air pressures of the electronic device are in a balanced state.

[0004] However, due to the highly concentrated functions of electronic equipment, the structural space is crowded, the height of the balance channel is relatively small, and the waterproof and breathable membrane sealed in the balance hole is in a suspended state. The waterproof and breathable membrane is easily squeezed and deformed under the action of external forces in the height direction and blocks the balance channel, causing failure of the air pressure balance hole channel structure. Utility Model Content

[0005] The technical problem to be solved by the utility model is: in view of the problem that the waterproof and breathable membrane of the existing electronic equipment is easily squeezed and deformed under the external force in the height direction and blocks the balance channel, an air pressure balance hole channel structure and an electronic equipment are provided.

[0006] In order to solve the above technical problems, on the one hand, the embodiment of the utility model provides an air pressure balance hole channel structure, including a waterproof breathable membrane, a shell and a structural member installed inside the shell, the shell is provided with a connecting hole connected to the outside, the structural member is provided with a balance hole, a balance channel and a support platform, the balance hole is connected between the connecting hole and the balance channel;

[0007] The support platform is arranged in the balancing channel, the waterproof and breathable membrane is sealed in the balancing hole, and the top surface of the support platform supports the waterproof and breathable membrane.

[0008] Optionally, the bottom surface of the support platform is connected to the bottom wall of the balancing channel.

[0009] Optionally, a plurality of support platforms are provided, and the plurality of support platforms are spaced apart from each other.

[0010] Optionally, an air flow channel is formed between the outer peripheral surface of the support platform and the inner wall of the balance channel, and the air flow channel is connected with the communication hole through the waterproof and breathable membrane.

[0011] Optionally, the plurality of support platforms are spaced apart along a preset circle, and the center of the preset circle is concentric with the center of a surface of the waterproof breathable membrane facing away from the communicating hole.

[0012] Optionally, the outer peripheral surface of the support platform includes an arcuate surface, a first vertical surface and a second vertical surface, a side of the first vertical surface close to the center of the preset circle and a side of the second vertical surface close to the center of the preset circle are connected at a preset position, and the arcuate surface is connected to a side of the first vertical surface away from the center of the preset circle and a side of the second vertical surface away from the center of the preset circle;

[0013] The arc surface is concentric with the preset circumference, and the arc surfaces of the plurality of support platforms are coplanar.

[0014] Optionally, the preset positions of the plurality of support platforms are located on a cylindrical surface with the center of the preset circle as the center.

[0015] Optionally, along the circumference of the preset circle, relative surfaces of adjacent support platforms are arranged in parallel and spaced apart.

[0016] Optionally, the balancing channel includes a first channel and a second channel, the second channel is located on a side of the first channel close to the center of the shell and is connected to the first channel, and the support platform is arranged in the first channel.

[0017] Optionally, the housing includes a transparent cover, the transparent cover is arranged on the structural member, and the communicating hole is arranged on the transparent cover;

[0018] The structural member includes a main board bracket, a first channel decorative member and a second channel decorative member, the first channel decorative member and the second channel decorative member are arranged at intervals on the top side of the main board bracket to form the second channel, the first channel is arranged on the side of the main board bracket facing the first channel decorative member, and the balancing hole is arranged on the first channel decorative member.

[0019] Optionally, a waterproof and breathable membrane is sealingly connected between the top surface of the support platform and the inner wall of the shell.

[0020] Optionally, a rear sound cavity of the earpiece is provided in the shell, and the communication hole is arranged corresponding to the rear sound cavity of the earpiece.

[0021] Compared with the prior art in which the waterproof and breathable membrane is suspended and sealed in the balancing hole, the air pressure balancing hole channel structure of the utility model realizes the connection between the balancing hole and the connecting hole, and at the same time, the top surface of the support platform arranged in the balancing channel supports the waterproof and breathable membrane to avoid deformation of the waterproof and breathable membrane under the action of external force in the height direction, which blocks the balancing channel and causes the failure of the air pressure balancing hole channel structure, thereby improving the stability of the air pressure balancing hole channel structure during operation.

[0022] On the other hand, an embodiment of the present utility model provides an electronic device, including the above-mentioned air pressure balance hole channel structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the air pressure balance hole channel structure provided by an embodiment of the utility model when the housing is hidden;

[0024] Figure 2 yes Figure 1 AA section view when the shell is not hidden;

[0025] Figure 3 yes Figure 1 A schematic diagram of the structure when the first channel decorative element and the second channel decorative element are hidden;

[0026] Figure 4 yes Figure 3 Airflow path diagram in .

[0027] The reference numerals in the specification are as follows:

[0028] 1. Shell; 11. Connecting hole; 2. Structural member; 21. Balance hole; 22. Balance channel; 221. First channel; 222. Second channel; 23. Support platform; 231. Arc surface; 232. First vertical surface; 233. Second vertical surface; 24. First channel decoration piece; 25. Second channel decoration piece; 26. Mainboard bracket; 27. Sound cavity behind earpiece; 3. Waterproof and breathable membrane. DETAILED DESCRIPTION

[0029] In order to make the technical problems, technical solutions and beneficial effects solved by the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0030] like Figure 1 and Figure 2As shown, an embodiment of the utility model provides an air pressure balance hole channel structure, including a waterproof breathable membrane 3, a shell 1 and a structural member 2 installed inside the shell 1, the shell 1 is provided with a connecting hole 11 connected to the outside, the structural member 2 is provided with a balance hole 21, a balance channel 22 and a support platform 23, and the balance hole 21 is connected between the connecting hole 11 and the balance channel 22.

[0031] The support platform 23 is disposed in the balancing channel 22 , the waterproof breathable membrane 3 is sealed in the balancing hole 21 , and the top surface of the support platform 23 supports the waterproof breathable membrane 3 .

[0032] The waterproof breathable membrane 3 is a breathable waterproof membrane. When water vapor condenses and deforms water droplets, the particles become larger. Due to the surface tension of the water droplets, water molecules cannot smoothly break away from the water droplets and penetrate to the other side, which prevents water penetration, making the waterproof breathable membrane 3 waterproof. When there is a pressure difference on both sides of the waterproof breathable membrane 3, the gas on both sides of the waterproof breathable membrane 3 can be exchanged through the waterproof breathable membrane 3 to balance the air pressure on both sides of the waterproof breathable membrane 3.

[0033] Specifically, for an electronic device with waterproof performance, the shell 1 is equivalent to a closed space. When the environment in the closed space changes and a pressure difference is generated inside and outside the shell 1, the external gas enters the balance channel 22 through the circulation hole and the waterproof breathable membrane 3, and the gas in the sealed space can also pass through the balance channel 22 and be discharged through the waterproof breathable membrane 3 and the connecting hole 11 to achieve two-way circulation of gas inside and outside the shell 1, so that the air pressure inside and outside the shell 1 reaches a balanced state, avoiding noise caused by the imbalance of air pressure inside and outside the shell 1 when the speaker or the earpiece is working.

[0034] It should be noted that the area on the waterproof breathable membrane 3 corresponding to the connecting hole 11 is the breathable area. In order to achieve the connection between the balancing hole 21 and the connecting hole 11 and the balancing channel 22, the top surface of the support platform 23 should not support the entire breathable area of ​​the waterproof breathable membrane 3, so as to avoid the support platform 23 blocking the breathable area, so that the outside gas can enter the balancing channel 22 through the breathable area, and the gas in the balancing channel 22 can be discharged to the outside through the breathable area.

[0035] Compared with the prior art in which the waterproof breathable membrane 3 is suspended and sealed in the balance hole 21, the support platform 23 in the balance channel 22 of the utility model supports the waterproof breathable membrane 3 to prevent the waterproof breathable membrane 3 from deforming and blocking the balance channel 22 under the external force in the height direction, thereby causing the air pressure balance hole channel structure to fail, thereby improving the stability of the air pressure balance hole channel structure during operation. Moreover, the support platform 23 is arranged in the balance channel 22, and the support platform 23 is arranged using the original space of the balance channel 22, which does not increase the height occupied space of the air pressure balance hole channel structure. Therefore, the air pressure balance hole channel structure can also be applied to electronic devices with highly concentrated functions and crowded structural space.

[0036] Compared with the prior art in which the waterproof breathable membrane 3 is suspended and sealed in the balance hole 21, the air pressure balance hole channel structure of the utility model realizes that the balance hole 21 connects the balance channel 22 and the connecting hole 11, and at the same time, the top surface of the support platform 23 arranged in the balance channel 22 supports the waterproof breathable membrane 3 to avoid deformation of the waterproof breathable membrane 3 under the action of external force in the height direction, blocking the balance channel 22 and causing the air pressure balance hole channel structure to fail, thereby improving the stability of the air pressure balance hole channel structure during operation.

[0037] In one embodiment, the bottom surface of the support platform 23 is connected to the bottom wall of the balancing channel 22. Compared with the side wall of the support platform 23 being connected to the inner wall of the balancing channel 22, this design makes the structure of the support platform 23 simple and easy to process, and eliminates the connection structure connecting the side wall of the support platform 23 and the inner wall of the balancing channel 22, so that the support platform 23 occupies a smaller space.

[0038] In one embodiment, if Figure 3 and Figure 4 As shown, a plurality of support platforms 23 are provided, and the plurality of support platforms 23 are spaced apart from each other. Figure 4 11' shown in the figure is the projection of the connecting hole 11 on the bottom wall of the balance channel 22. The external airflow is dispersed into multiple small airflows after passing through the waterproof breathable membrane 3. The multiple small airflows flow to the intervals between adjacent support platforms 23 respectively, and then the small airflows flow to other positions in the airflow channel.

[0039] The plurality of support platforms 23 respectively support a plurality of positions on the waterproof breathable membrane 3 , thereby improving the balance of force on the waterproof breathable membrane 3 and further improving the stability of the support platforms 23 in supporting the waterproof breathable membrane 3 .

[0040] In one embodiment, if Figure 3 and Figure 4 As shown, an air flow channel is formed between the outer peripheral surface of the support platform 23 and the inner wall of the balancing channel 22, and the air flow channel is connected to the connecting hole 11 through the waterproof breathable membrane 3, so that the small air flow in the interval between adjacent support platforms 23 can continue to flow to the outside of the support platform 23, and flow in a unidirectional direction along the outer peripheral direction of the support platform 23 in the air flow channel, so that the path of the external air flow into the balancing channel 22 is unidirectional, so as to avoid confusion in the flow direction of the air flow in the balancing channel 22, which is beneficial to increasing the flow speed of the gas, and then increasing the speed of gas exchange inside and outside the shell 1.

[0041] In one embodiment, a plurality of support platforms 23 are distributed at intervals along a preset circle, and the center of the preset circle is concentric with the center of the surface of the side of the waterproof breathable membrane 3 facing away from the connecting hole 11, that is, a plurality of support platforms 23 are distributed at intervals around the center of the surface of the side of the waterproof breathable membrane 3 facing away from the connecting hole 11, so that the supporting positions of the plurality of support platforms 23 supporting the waterproof breathable membrane 3 are distributed at intervals along the preset circle, so as to further improve the balance of the force on the waterproof breathable membrane 3, and further improve the stability of the support platforms 23 in supporting the waterproof breathable membrane 3.

[0042] In one embodiment, if Figure 3 As shown, the outer circumferential surface of the support platform 23 includes an arcuate surface 231, a first vertical surface 232 and a second vertical surface 233, and a side of the first vertical surface 232 close to the center of the preset circle and a side of the second vertical surface 233 close to the center of the preset circle are connected at a preset position. Figure 3 The position indicated by A in the figure is the preset position, and the arc surface 231 is connected to the side of the first vertical surface 232 away from the center of the preset circle and the side of the second vertical surface 233 away from the center of the preset circle.

[0043] The arc surface 231 is concentric with the preset circle, and the arc surfaces 231 of multiple support platforms 23 are coplanar. After the airflow flows into the airflow channel from the gaps between adjacent support platforms 23, the airflow flows along the outer peripheral direction of the arc surface 231. The arc surface 231 has no edges and corners, which can prevent the support platform 23 from obstructing the airflow flow, and is conducive to smooth flow of airflow.

[0044] In one embodiment, the waterproof breathable membrane 3 is circular, and the outer diameter of the waterproof breathable membrane 3 is the same as the diameter of the arc surface 231 .

[0045] In one embodiment, the preset positions of the plurality of support platforms 23 are located on a cylindrical surface with the center of the preset circle as the center, so that each support platform 23 is at a certain distance from the center of the waterproof breathable membrane 3, so that each support platform 23 can avoid the breathable area of ​​the waterproof breathable membrane 3 as much as possible, so as to facilitate the external airflow to enter the balance channel 22 through the waterproof breathable membrane 3, and the airflow in the balance channel 22 to be discharged through the waterproof breathable membrane 3.

[0046] In one embodiment, along the circumference of a preset circle, the relative surfaces of adjacent support platforms 23 are arranged in parallel and spaced apart, so that the intervals between adjacent support platforms 23 form a straight channel of equal width, which is conducive to the smooth flow of airflow in the straight channel.

[0047] In one embodiment, four support platforms 23 are provided, and the four support platforms 23 are evenly spaced apart along the circumferential direction of the second vertical surface 233 .

[0048] In one embodiment, the first vertical surface 232 of the support platform 23 is perpendicular to the second vertical surface 233 .

[0049] In one embodiment, a side of the first vertical surface 232 close to the center of the preset circle and a side of the second vertical surface 233 close to the center of the preset circle are in an arc transition.

[0050] In one embodiment, the balancing channel 22 includes a first channel 221 and a second channel 222. The second channel 222 is located on a side of the first channel 221 close to the center of the housing 1 and communicates with the first channel 221. The support platform 23 is disposed in the first channel 221. The volume requirement of the balancing channel 22 is met by two channels to reduce the size of a single channel, thereby facilitating the design of the first channel 221 and the second channel 222 on an electronic device with limited structural space.

[0051] In one embodiment, a sink is provided inside the structural member 2 at the bottom of the balancing hole 21 , the sink forms the first channel 221 , and the support platform 23 is connected to the bottom wall of the sink.

[0052] In one embodiment, the sink is circular, and a gap is provided between the inner wall of the sink and the outer peripheral surface of the support platform 23 to form the above-mentioned air flow channel.

[0053] In one embodiment, the second channel 222 is arc-shaped, and the first channel 221 is located on one radial side of the second channel 222 .

[0054] In one embodiment, one circumferential end of the second channel 222 is communicated with the first channel 221 .

[0055] In one embodiment, the housing 1 includes a transparent cover, which is disposed on the structural member 2, and the communication hole 11 is disposed on the transparent cover.

[0056] The structural component 2 includes a main board bracket 26, a first channel decoration component 24 and a second channel decoration component 25. The first channel decoration component 24 and the second channel decoration component 25 are spaced apart on the top side of the main board bracket 26 to form a second channel 222, so as to hide the second channel 222 under the first channel decoration component 24 and the second channel decoration component 25, thereby preventing the user from seeing the structure of the balance channel 22 through the transparent cover, and preventing the air pressure balance hole channel structure from destroying the appearance of the structural component 2 in the transparent cover, thereby improving the user experience.

[0057] The first channel 221 is disposed on a side of the mainboard bracket 26 facing the first channel decoration piece 24 , and the balancing hole 21 is disposed on the first channel decoration piece 24 .

[0058] In one embodiment, the waterproof and breathable membrane 3 is sealed and connected between the top surface of the support platform 23 and the inner wall of the housing 1 .

[0059] In one embodiment, the waterproof and breathable membrane 3 is glued to the inner wall of the housing 1 by means of a sealant.

[0060] In one embodiment, the balancing hole 21 is a circular hole, the waterproof breathable membrane 3 is circular, and the inner diameter of the balancing hole 21 is larger than the outer diameter of the waterproof breathable membrane 3, so as to avoid the hole wall of the balancing hole 21 hindering the insertion of the waterproof breathable membrane 3 when the waterproof breathable membrane 3 is placed on the support platform 23, thereby facilitating the installation of the waterproof breathable membrane 3.

[0061] In one embodiment, a receiver rear sound cavity 27 is defined in the housing 1 , and the communication hole 11 is disposed corresponding to the receiver rear sound cavity 27 .

[0062] In one embodiment, the diameter of the cylindrical surface where the preset positions of the plurality of support platforms 23 are located is 1.5 mm, the diameter of the coplanar arcuate surfaces 231 of the plurality of support platforms 23 is 3.9 mm, the height of the support platforms 23 is 0.15 mm, the interval between the opposite surfaces of adjacent support platforms 23 is 0.8 mm, the diameter of the circular first channel 221 is 5.1 mm, the size of the arcuate second channel 222 is 8.5 mm long, 1.8 mm wide, and 0.1 mm deep, and the junction of the bottom wall of the first channel 221 and the bottom wall of the second channel 222 is tangently transitioned. The bottom walls of the circumferential ends of the second channel 222 and the mainboard bracket 26 are tangently transitioned, which not only ensures the channel function but also ensures that the appearance of the transparent cover inner structure 2 is not damaged.

[0063] In other embodiments, a plurality of connecting arms may be provided on the outer peripheral surface of the support platform 23, and the support platform 23 may be connected to the inner wall of the balancing channel 22 via the plurality of connecting arms. It should be noted that the connecting arms should be prevented from obstructing the flow of gas in the balancing channel 22. For example, the height of the connecting arms may be less than the depth of the balancing channel 22.

[0064] In other embodiments, only one support platform 23 may be provided, and the cross section of the support platform 23 may be cross-shaped.

[0065] In other embodiments, the number of support platforms 23 can be adjusted according to design requirements, and two, three, five or more support platforms 23 can be provided.

[0066] In other embodiments, the plurality of support platforms 23 may be distributed in a circular array, or in a rectangular array, or of course, in an irregular array.

[0067] In other embodiments, the outer peripheral surface of the support platform 23 can be in contact with the inner wall of the balance channel 22. At this time, the external airflow passes through the waterproof breathable membrane 3 and flows into the gap between adjacent support platforms 23, and then flows to other areas of the balance channel 22.

[0068] In other embodiments, the cross-sectional shape of the support platform 23 may be circular, polygonal, elliptical or other irregular shapes.

[0069] In other embodiments, the preset positions of the plurality of support platforms 23 may be located on the outer circumferential surface of a polygonal column centered at the center of a preset circle.

[0070] In other embodiments, the angle between the opposing surfaces of adjacent support platforms 23 may be non-zero.

[0071] In other embodiments, only the first channel 221 may be provided. In this case, in order to ensure the volume of the entire balancing channel 22 and to meet the gas exchange speed requirement, the size of the first channel 221 may be increased.

[0072] In addition, an embodiment of the utility model provides an electronic device, including the air pressure balance hole channel structure of the above embodiment, wherein the electronic device includes but is not limited to a waterproof mobile phone, a waterproof watch, a waterproof tablet, etc.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A pressure balance hole channel structure, characterized in that: The invention comprises a waterproof breathable membrane (3), a shell (1) and a structural member (2) installed inside the shell (1); the shell (1) is provided with a connecting hole (11) communicating with the outside; the structural member (2) is provided with a balancing hole (21), a balancing channel (22) and a support platform (23); the balancing hole (21) is connected between the connecting hole (11) and the balancing channel (22); The support platform (23) is arranged in the balancing channel (22), the waterproof breathable membrane (3) is sealed in the balancing hole (21), and the top surface of the support platform (23) supports the waterproof breathable membrane (3).

2. The air pressure balance hole channel structure according to claim 1, characterized in that: The bottom surface of the support platform (23) is connected to the bottom wall of the balancing channel (22).

3. The air pressure balance hole channel structure according to claim 1, characterized in that: A plurality of the support platforms (23) are provided, and the plurality of the support platforms (23) are spaced apart from each other.

4. The air pressure balance hole channel structure according to claim 3, characterized in that: An air flow channel is formed between the outer peripheral surface of the support platform (23) and the inner wall of the balance channel (22), and the air flow channel is connected to the communication hole (11) through the waterproof and breathable membrane (3).

5. The air pressure balance hole channel structure according to claim 4, characterized in that: The plurality of support platforms (23) are distributed at intervals along a preset circle, and the center of the preset circle is concentric with the center of a surface of the waterproof breathable membrane (3) on one side facing away from the connecting hole (11).

6. The air pressure balance hole channel structure according to claim 5, characterized in that: The outer peripheral surface of the support platform (23) comprises an arcuate surface (231), a first vertical surface (232) and a second vertical surface (233), wherein a side of the first vertical surface (232) close to the center of the preset circle and a side of the second vertical surface (233) close to the center of the preset circle are connected at a preset position, and the arcuate surface (231) is connected to a side of the first vertical surface (232) away from the center of the preset circle and a side of the second vertical surface (233) away from the center of the preset circle; The arc surface (231) is concentric with the preset circumference, and the arc surfaces (231) of the plurality of support platforms (23) are coplanar.

7. The air pressure balance hole channel structure according to claim 6, characterized in that: The preset positions of the plurality of support platforms (23) are located on a cylindrical surface with the center of the preset circle as the center.

8. The air pressure balance hole channel structure according to claim 6, characterized in that: Along the circumference of the preset circle, the relative surfaces of adjacent support platforms (23) are arranged in parallel and at intervals.

9. The air pressure balance hole channel structure according to claim 1, characterized in that: The balancing channel (22) comprises a first channel (221) and a second channel (222); the second channel (222) is located on a side of the first channel (221) close to the center of the shell (1) and is connected to the first channel (221); and the support platform (23) is arranged in the first channel (221).

10. The air pressure balance hole channel structure according to claim 9, characterized in that: The housing (1) comprises a transparent cover, the transparent cover is arranged on the structural member (2), and the communicating hole (11) is arranged on the transparent cover; The structural member (2) comprises a main board support (26), a first channel decorative member (24) and a second channel decorative member (25); the first channel decorative member (24) and the second channel decorative member (25) are arranged at intervals on the top side of the main board support (26) to form the second channel (222); the first channel (221) is arranged on a side of the main board support (26) facing the first channel decorative member (24); and the balancing hole (21) is arranged on the first channel decorative member (24).

11. The air pressure balance hole channel structure according to any one of claims 1 to 10, characterized in that: The housing (1) has a receiver rear sound cavity (27) in it, and the communication hole (11) is arranged corresponding to the receiver rear sound cavity (27).

12. An electronic device, characterized in that: An air pressure balance hole channel structure comprising any one of claims 1 to 11.

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