A vehicle-mounted microphone assembly with a ventilation cavity

Abstract

This utility model discloses a vehicle-mounted microphone assembly with a ventilation cavity, including a housing, a microphone unit disposed within the housing, and a sound guiding structure formed on the housing. The microphone unit includes a main substrate that divides the inner cavity of the housing into an independent front cavity and a rear cavity. An integrated circuit board located in the rear cavity is disposed on the main substrate. A through hole connecting the front and rear cavities is formed on the main substrate. A sound transducer located in the rear cavity and spanning the through hole is also disposed on the main substrate. An inner cylinder coaxially disposed with the housing is disposed inside the rear cavity. The inner cylinder divides the rear cavity into an inner cavity and a ventilation cavity surrounding the outer side of the inner cavity. The ventilation cavity is filled with a porous sound-absorbing material. The sound guiding structure includes a main sound inlet formed on the housing and communicating with the front cavity, a ventilation hole communicating with the ventilation cavity, and a connecting hole formed on the top of the inner cylinder. This invention can significantly suppress wind noise while providing an independent and stable working environment for the integrated circuit.

Description

Technical Field

[0001] This utility model relates to the field of vehicle microphone technology, specifically to a vehicle microphone assembly with a ventilation cavity. Background Technology

[0002] With the development of automotive intelligence, in-vehicle voice recognition and hands-free calling have become standard features. The core of these functions is the in-vehicle microphone. However, in-vehicle microphones operate in harsh environments, facing two major challenges, especially at high speeds: First, strong wind noise can enter through the sound inlet, drowning out the effective human voice signal, leading to a decrease in voice recognition rate or unclear calls; second, rapidly changing external air pressure acts on one side of the microphone diaphragm, causing an imbalance in air pressure on both sides of the diaphragm, resulting in low-frequency distortion and even damage to the microphone unit.

[0003] Existing technologies typically employ simple windshields or sponges at the microphone's sound inlet to reduce noise. While this method is effective in low-speed breezes, its effectiveness is limited against the stable wind pressure and turbulence generated by high-speed driving, and it fails to address the pressure balance issues caused by rapid pressure fluctuations. Furthermore, traditional MEMS microphones often encapsulate the integrated circuit and diaphragm on the same back substrate, housed together in the rear cavity. This structure makes acoustic treatment of the rear cavity (such as the application of sound-absorbing materials) difficult, as these materials may hinder IC heat dissipation or affect its acoustic performance, making it challenging to simultaneously achieve pressure balance, noise reduction, and component reliability. Therefore, there is an urgent need for a highly reliable automotive microphone assembly that can effectively isolate wind noise, balance air pressure, and ensure the normal operation of core electronic components. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide a vehicle-mounted microphone assembly with a ventilation cavity to effectively balance the air pressure on both sides of the microphone diaphragm, significantly suppress wind noise, and at the same time provide an independent and stable working environment for integrated circuits.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows.

[0006] A vehicle-mounted microphone assembly with a ventilation cavity includes a housing, a microphone unit disposed within the housing, and a sound guiding structure formed on the housing to guide sound into the microphone unit. The microphone unit includes a main substrate that divides the interior of the housing into a front cavity and a rear cavity. An integrated circuit board located in the rear cavity and electrically connected to the main substrate is disposed on the main substrate. A through-hole connecting the front and rear cavities is formed on the main substrate. An acoustic transducer located in the rear cavity, spanning the through-hole, and electrically connected to the integrated circuit board is also disposed on the main substrate. An inner cylinder coaxially disposed with the housing is disposed inside the rear cavity. The inner cylinder divides the rear cavity into an inner cavity opposite to the microphone unit and a ventilation cavity surrounding the outer side of the inner cavity. The ventilation cavity is filled with a porous sound-absorbing material. The sound guiding structure includes a main sound inlet formed on the housing and communicating with the front cavity, a ventilation hole communicating with the ventilation cavity, and a connecting hole formed on the top of the inner cylinder to communicate between the ventilation cavity and the inner cavity.

[0007] Preferably, the acoustic transducer includes an acoustic transducer substrate disposed on a main substrate, and a diaphragm disposed on the acoustic transducer substrate opposite to the through hole.

[0008] Preferably, the main sound inlet is opened on the front end face and the front side of the outer shell and communicates with the front cavity, and a first dustproof net is provided at the main sound inlet.

[0009] Preferably, the connecting hole is formed circumferentially along the top of the inner cylinder.

[0010] Preferably, the ventilation hole is located on the rear end face of the outer shell and communicates with the ventilation cavity, and a second dustproof net is provided at the ventilation hole.

[0011] Preferably, the porous sound-absorbing material is spaced apart from the ventilation holes, and the porous sound-absorbing material is sponge, foam, or sintered metal mesh.

[0012] The technological advancements achieved by this utility model are as follows, due to the adoption of the above technical solutions.

[0013] This invention boasts superior acoustic performance: it picks up human voices through a path of "main inlet - front cavity - through hole - diaphragm," while wind noise and air pressure fluctuations act on the back of the diaphragm through a path of "ventilation hole - ventilation cavity (containing porous sound-absorbing material) - connecting hole - inner cavity." The porous sound-absorbing material efficiently attenuates broadband wind noise while allowing static air pressure to pass through slowly, thus effectively suppressing wind noise while perfectly balancing the air pressure on both sides of the diaphragm, eliminating low-frequency distortion and potential physical damage.

[0014] This invention offers high component protection and reliability: the inner cylinder structure divides the rear cavity into an independent inner cavity and a ventilation cavity. The core acoustic transducer and integrated circuit board are sealed in a clean and stable inner cavity, completely avoiding the influence of dust and moisture that may be introduced by porous sound-absorbing materials, and facilitating heat dissipation and long-term reliable operation of the integrated circuit. The ventilation cavity is specifically designed to handle noise and balance air pressure; each component performs its specific function, enhancing the overall reliability of the assembly.

[0015] This invention achieves a pressure equalization design: the circumferentially opened connecting holes allow the filtered airflow to enter the inner cavity evenly, providing a uniform acoustic load on the back of the diaphragm and helping to obtain a flatter frequency response. Attached Figure Description

[0016] Figure 1 This is a first-view structural diagram of the present invention; Figure 2 This is a schematic diagram of the second-view structure of the present invention; Figure 3 This is a longitudinal sectional view of the present invention.

[0017] Among them: 1. Outer shell, 2. Main substrate, 21. Through hole, 3. Front cavity, 4. Rear cavity, 5. Integrated circuit board, 6. Acoustic transducer, 61. Acoustic transducer substrate, 62. Diaphragm, 7. Main sound inlet hole, 8. Ventilation hole, 9. Inner cylinder, 10. Inner cavity, 11. Ventilation cavity, 12. Porous sound-absorbing material, 13. Connecting hole. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0019] A vehicle-mounted microphone assembly with a ventilation cavity, combined with Figures 1 to 3 As shown, it includes a housing 1, a microphone unit, and a sound guiding structure. The housing 1 is cylindrical. The microphone unit is located inside the housing 1. The sound guiding structure is formed on the housing 1 and is used to guide sound into the microphone unit.

[0020] The microphone unit includes a main substrate 2, which divides the interior of the outer shell 1 into two independent chambers: a front cavity 3 and a rear cavity 4. An integrated circuit board 5 is mounted on the main substrate 2, located in the rear cavity 4 and electrically connected to the main substrate 2. A through-hole 21 is formed in the center of the main substrate 2, connecting the front cavity 3 and the rear cavity 4. An acoustic transducer 6 is also mounted on the main substrate 2, located in the rear cavity 4 and spanning the through-hole 21. The acoustic transducer 6 is electrically connected to the integrated circuit board 5 via bonding wires or similar means. Specifically, the acoustic transducer 6 includes an acoustic transducer substrate 61, which is mounted on the main substrate 2. A diaphragm 62 is mounted on the acoustic transducer substrate 61, and the diaphragm 62 is positioned opposite the through-hole 21.

[0021] The rear cavity 4 is provided with an inner cylinder 9, which is coaxially arranged with the outer shell 1. The inner cylinder 9 divides the rear cavity 4 into an inner cavity 10 and a ventilation cavity 11. The inner cavity 10 is arranged opposite to the microphone unit, thereby surrounding the microphone unit. The ventilation cavity 11 is annular and surrounds the outer side of the inner cavity 10. The ventilation cavity 11 is filled with a porous sound-absorbing material 12, which is a sponge, foam or metal sintered mesh, and preferably an acoustic sponge.

[0022] The sound guiding structure includes a main sound inlet 7, a ventilation hole 8, and a connecting hole 13. The main sound inlet 7 is located on the outer shell 1 and communicates with the front cavity 3. Specifically, the main sound inlet 7 is located on the front end face and the front side face of the outer shell 1 and communicates with the front cavity 3. A first dustproof net is provided at the main sound inlet 7 to prevent dust from entering the front cavity 3. The ventilation hole 8 is located on the rear end face of the outer shell 1 and communicates with the ventilation cavity 11. The ventilation hole 8 is spaced apart from the porous sound-absorbing material 12. A second dustproof net is provided at the ventilation hole 8 to prevent dust from entering the ventilation cavity 11. The connecting hole 13 is located at the top of the inner cylinder 9 and is used to connect the ventilation cavity 11 with the inner cavity 10. Specifically, the connecting hole 13 is evenly distributed along the top circumference of the inner cylinder 9.

[0023] The working principle of this utility model is as follows: The human voice signal enters the front cavity 3 through the main sound inlet 7, and then acts on the front of the diaphragm 62 of the sound transducer 6 through the through hole 21, causing it to vibrate and generate an electrical signal, which is then processed and output by the integrated circuit board 5.

[0024] When external air pressure changes or wind noise is generated, it enters the ventilation cavity 11 through the ventilation hole 8 on the rear end face. The porous sound-absorbing material 12 inside the ventilation cavity 11 efficiently absorbs and attenuates the rapidly fluctuating wind noise over a wide frequency range. The filtered, stable airflow then diffuses evenly into the sealed inner cavity 10 through the circumferential connecting hole 13 at the top of the inner cylinder 9, and finally acts on the back side of the diaphragm 62.

[0025] This design ensures that the front of the diaphragm 62 (through the front cavity 3) is exposed to the human voice signal, while the back (through the inner cavity 10) is exposed to the filtered and equalized ambient air pressure. This perfectly balances static air pressure, protects the microphone, and minimizes wind noise interference, significantly improving the speech clarity and signal-to-noise ratio of the vehicle microphone in harsh environments such as high speeds and strong winds.

Claims

1. A vehicle-mounted microphone assembly with a ventilation cavity, comprising a housing (1), a microphone unit disposed within the housing (1), and a sound guiding structure formed on the housing (1) to guide sound into the microphone unit, characterized in that: The microphone unit includes a main substrate (2), which divides the interior of the outer shell (1) into a front cavity (3) and a rear cavity (4) that are independent of each other. An integrated circuit board (5) is provided on the main substrate (2) and is located in the rear cavity (4) and electrically connected to the main substrate (2). A through hole (21) is provided on the main substrate (2) to connect the front cavity (3) and the rear cavity (4). An acoustic transducer (6) is also provided on the main substrate (2) and is located in the rear cavity (4) and is provided across the through hole (21) and electrically connected to the integrated circuit board (5). The rear cavity (4) is provided with There is an inner cylinder (9) coaxially arranged with the outer shell (1). The inner cylinder (9) divides the rear cavity (4) into an inner cavity (10) opposite to the microphone unit and a ventilation cavity (11) surrounding the outer side of the inner cavity (10). The ventilation cavity (11) is filled with a porous sound-absorbing material (12). The sound guiding structure includes a main sound inlet (7) opened on the outer shell (1) and communicating with the front cavity (3), a ventilation hole (8) communicating with the ventilation cavity (11), and a connecting hole (13) opened on the top of the inner cylinder (9) to realize the communication between the ventilation cavity (11) and the inner cavity (10).

2. The vehicle-mounted microphone assembly with a ventilation cavity according to claim 1, characterized in that: The acoustic transducer (6) includes an acoustic transducer substrate (61) disposed on the main substrate (2), and a diaphragm (62) disposed on the acoustic transducer substrate (61) opposite to the through hole (21).

3. The vehicle-mounted microphone assembly with a ventilation cavity according to claim 1, characterized in that: The main sound inlet (7) is opened on the front end face and front side of the outer shell (1) and communicates with the front cavity (3), and a first dustproof net is provided at the main sound inlet (7).

4. The vehicle-mounted microphone assembly with a ventilation cavity according to claim 1, characterized in that: The connecting hole (13) is opened circumferentially along the top of the inner cylinder (9).

5. A vehicle-mounted microphone assembly with a ventilation cavity according to claim 1, characterized in that: The ventilation hole (8) is located on the rear end face of the outer shell (1) and communicates with the ventilation cavity (11), and a second dustproof net is provided at the ventilation hole (8).

6. A vehicle-mounted microphone assembly with a ventilation cavity according to claim 5, characterized in that: The porous sound-absorbing material (12) is spaced apart from the ventilation holes (8), and the porous sound-absorbing material (12) is a sponge, foam or metal sintered mesh.

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