A vehicle headrest, vehicle seat, vehicle for noise reduction, and noise reduction method

Abstract

The present invention discloses a vehicle headrest for sound absorption, a vehicle seat, a vehicle and a sound absorption method, which relate to the technical field of vehicle noise reduction. The vehicle headrest includes a micro-perforated plate provided with a plurality of micro-holes; a pillow portion disposed on one side of the micro-perforated plate, and the pillow portion is communicated with the micro-holes; a noise reduction cavity disposed on the other side of the micro-perforated plate, and the noise reduction cavity is communicated with the pillow portion through the micro-holes; an adjusting device for adjusting the functional volume of the noise reduction cavity according to a target frequency determined by the motor speed so as to adjust the sound absorption frequency. Sound absorption is carried out by using the principle of a resonance absorber. By collecting the motor speed signal, the target frequency is calculated, and the adjusting device changes the functional volume of the noise reduction cavity according to the target frequency to adjust the sound absorption frequency. The adjustment method is simple, convenient and fast. It solves the problems in the prior art that it is difficult to perform active adjustment to cope with noises of different frequencies or the active adjustment structure is complex.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle noise reduction, and particularly relates to an in-vehicle headrest, an in-vehicle seat, a vehicle and a noise reduction method for sound absorption. Background Art

[0002] With the rise of the new energy vehicle trend, the vehicle noise has changed from mainly medium and low frequencies to mainly high-frequency whistling sounds, and there is an urgent need for active control means capable of controlling high-frequency whistling or high-frequency electromagnetic sounds.

[0003] During the vehicle driving process, the position of the human ear and the position of the headrest are highly matched. Designing an acoustic environment with a high acoustic impedance for prominent noises in the headrest area can greatly improve the user experience.

[0004] In the prior art, the cavity noise reduction structure adopted by vehicles is to use a sheet-like flexible sound-absorbing material to divide all or part of the space of the cavity into multiple cavities according to a set size and shape, form a sound-absorbing material back cavity with the cavities, and use the sound-absorbing material back cavity to obtain a sound-absorbing effect for noises in a specific frequency band. There are problems that it is difficult to actively adjust to cope with noises of different frequencies or the active adjustment structure is complex. Summary of the Invention

[0005] Aiming at the defects existing in the prior art, the purpose of the present invention is to provide an in-vehicle headrest, an in-vehicle seat, a vehicle and a noise reduction method for sound absorption, which can solve the problems that it is difficult to actively adjust to cope with noises of different frequencies or the active adjustment structure is complex in the prior art.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is:

[0007] On the one hand, an in-vehicle headrest for sound absorption is provided, which includes:

[0008] A micro-perforated plate, on which a plurality of micro-holes are opened;

[0009] A pillow part, which is arranged on one side of the micro-perforated plate, and the pillow part communicates with the micro-holes;

[0010] A noise reduction cavity, which is arranged on the other side of the micro-perforated plate, and the noise reduction cavity communicates with the pillow part through the micro-holes;

[0011] An adjusting device, which is used to adjust the functional volume of the noise reduction cavity according to the target frequency determined by the motor speed, so as to adjust the sound absorption frequency.

[0012] Based on the above technical solution,

[0013] In some alternative solutions, the adjusting device includes:

[0014] The isolation film is disposed inside the noise reduction cavity, dividing the noise reduction cavity into a noise reduction functional cavity and a variable cavity. The noise reduction functional cavity communicates with the occipital part through the micro-holes;

[0015] The driving mechanism drives the isolation film to change the volumes of the noise reduction functional cavity and the variable cavity.

[0016] In some alternative solutions, the driving mechanism is an air pump. The air pump communicates with the variable cavity through a pipeline. By changing the air volume inside the variable cavity, the position of the isolation film is changed to adjust the volume of the noise reduction functional cavity.

[0017] In some alternative solutions, the air pump is used to connect to the vehicle-mounted energy supply device through a circuit. The vehicle-mounted energy supply device is controlled by the vehicle-mounted ECU and receives the instructions of the vehicle-mounted ECU to perform inflation or deflation.

[0018] In some alternative solutions, a wrapping part is provided outside the noise reduction cavity. The wrapping part is connected to the occipital part to form a receiving cavity. The micro-perforated plate and the noise reduction cavity are both disposed in the receiving cavity.

[0019] In some alternative solutions, a plurality of through holes are formed in the occipital part. The through holes communicate with the micro-holes, and the opening directions of the through holes and the micro-holes are the same.

[0020] On the one hand, a sound absorption method is provided, which is implemented by using the above-mentioned vehicle-mounted headrest for sound absorption and includes the following steps:

[0021] Determine the target frequency according to the motor speed;

[0022] Determine the target volume required for the noise reduction cavity according to the target frequency;

[0023] Adjust the functional volume of the noise reduction cavity according to the target volume required for the noise reduction cavity to adjust the sound absorption frequency.

[0024] In some alternative solutions, according to the formula: , , , , determine the target volume required for the noise reduction cavity;

[0025] Wherein, is the target frequency, is the speed of sound, n is the number of micro-holes, s is the cross-sectional area of a single micro-hole, is the effective length of the micro-hole, V is the target volume of the noise reduction cavity, t is the thickness of the micro-perforated plate, is the inherent calculated value of the micro-perforated plate, d is the opening diameter of the micro-holes, B is the center distance between adjacent micro-holes, and D is the average depth of the target volume of the noise reduction cavity. is an intermediate parameter.

[0026] On the one hand, a vehicle seat is provided, which includes the above-mentioned vehicle headrest for sound absorption.

[0027] On the other hand, a vehicle is provided, which includes the above-mentioned vehicle seat.

[0028] Compared with the prior art, the advantages of the present invention are as follows:

[0029] When using the vehicle headrest for sound absorption, a plurality of micro-holes with the hole neck direction perpendicular to the plane direction of the micro-perforated plate are opened on the micro-perforated plate. The pillow part is arranged on one side of the micro-perforated plate and communicated with the micro-holes. The noise reduction cavity is arranged on the other side of the micro-perforated plate and communicated with the pillow part through the micro-holes. The resonance absorber principle is used for sound absorption. By adjusting the target frequency determined by the motor speed through the adjusting device, the functional volume of the noise reduction cavity is changed to adjust the sound absorption frequency. The adjustment method is simple, convenient and fast. It solves the problems in the prior art that it is difficult to actively adjust to cope with different frequency noises or the active adjustment structure is complex. Description of the Drawings

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained according to these drawings without creative efforts.

[0031] Figure 1 is a schematic structural diagram of an embodiment of a vehicle headrest for sound absorption according to the present invention;

[0032] Figure 2 is a schematic cross-sectional structural diagram of an embodiment of a vehicle headrest for sound absorption according to the present invention;

[0033] Figure 3 is a schematic top view structural diagram of an embodiment of a vehicle headrest for sound absorption according to the present invention;

[0034] Figure 4 is a schematic structural diagram of a micro-perforated plate in an embodiment of a vehicle headrest for sound absorption according to the present invention;

[0035] Figure 5 is a schematic diagram of the change of the structural sound absorption coefficient in an embodiment of a vehicle headrest for sound absorption according to the present invention.

[0036] In the figure: 1, occipital part; 2, through hole; 3, micro-perforated plate; 31, micro-holes; 4, noise reduction cavity; 41, noise reduction functional cavity; 42, variable cavity; 5, driving mechanism; 6, isolation membrane. Specific embodiments

[0037] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the scope of protection of the present application.

[0038] The following further elaborates in detail on embodiments of a vehicle headrest, vehicle seat, vehicle, and noise reduction method for noise reduction according to the present invention with reference to the accompanying drawings.

[0039] As Figures 1-4 shown, on the one hand, a vehicle headrest for noise reduction is provided, which includes:

[0040] A micro-perforated plate 3, on which a plurality of micro-holes 31 are provided;

[0041] An occipital part 1, which is arranged on one side of the micro-perforated plate 3, and the occipital part 1 communicates with the micro-holes 31;

[0042] A noise reduction cavity 4, which is arranged on the other side of the micro-perforated plate 3, and the noise reduction cavity 4 communicates with the occipital part 1 through the micro-holes 31;

[0043] An adjusting device, which is used to adjust the functional volume of the noise reduction cavity 4 according to the target frequency determined by the motor speed to adjust the noise reduction frequency.

[0044] When using this vehicle headrest for noise reduction, a plurality of micro-holes 31 with the hole neck direction perpendicular to the plane direction of the micro-perforated plate 3 are provided on the micro-perforated plate 3. The occipital part 1 is arranged on one side of the micro-perforated plate 3 and communicates with the micro-holes 31. The noise reduction cavity 4 is arranged on the other side of the micro-perforated plate 3 and communicates with the occipital part 1 through the micro-holes 31. The resonance absorber principle is used for noise reduction. The functional volume of the noise reduction cavity 4 is changed according to the target frequency determined by the motor speed through the adjusting device to adjust the noise reduction frequency. The adjustment method is simple, convenient and fast. It solves the problems in the prior art that it is difficult to perform active adjustment to cope with different frequency noises or the active adjustment structure is complex.

[0045] By collecting the motor speed signal, through calculating the target frequency, the principle formula of the micro-perforated plate 3 using the resonance absorber is , where , , , is the target frequency, is the speed of sound, n is the number of micropores 31, s is the cross-sectional area of a single micropore 31, is the effective length of the micropore 31, V is the functional volume of the noise reduction cavity 4, t is the thickness of the micro-perforated plate 3, is the inherent calculated value of the micro-perforated plate 3, d is the opening diameter of the micropore 31, B is the center distance between adjacent micropores 31, is an intermediate parameter, D is the average depth of the functional volume of the noise reduction cavity 4. In this solution, except for all are fixed values, only changes with the change of D. The functional volume V of the noise reduction cavity 4 is equal to the area of the micro-perforated plate 3 multiplied by the average depth D of the functional volume of the noise reduction cavity 4. The area of the micro-perforated plate 3 is a fixed value. Therefore, by adjusting the device to change the functional volume V of the noise reduction cavity 4 according to the target frequency, the frequency of sound absorption can be adjusted.

[0046] In this example, the micro-perforated plate 3 is made of a rigid material and is fixedly connected to the skeleton of the headrest to prevent the pressure of the occiput 1 on the micro-perforated plate 3 from deforming the micro-perforated plate 3 and causing the resonance absorber to lose its effect, thereby improving the structural stability; the micropores 31 are arranged in a matrix on the micro-perforated plate 3, and the distance between adjacent micropores 31 is the same, which is simpler in the process manufacturing stage and convenient for production and manufacturing.

[0047] In this example, the sound absorption principle of the micro-perforated plate 3: When sound waves reach the structure of the micropores 31 and the noise reduction cavity 4, the gas in the necks of the micropores 31 moves back and forth like a piston under the pressure of the sound waves. The moving gas has a certain mass, and it resists the change in the moving speed caused by the action of the sound waves. At the same time, when the sound waves enter the micropores 31, due to the friction and damping of the walls of the necks of the micropores 31, part of the sound energy is converted into heat energy and consumed. When the frequency of the external sound waves is the same as the natural frequency of the micropores 31 and the noise reduction cavity 4, resonance occurs in the system. At this time, the sound energy loss caused by the back-and-forth movement and friction of the air column in the necks of the micropores 31 is the largest, so as to achieve the purpose of sound absorption and noise reduction for a specific frequency.

[0048] As Figures 1-3 shown, in some alternative embodiments, the adjusting device includes:

[0049] An isolation film 6, which is arranged inside the noise reduction cavity 4 and divides the noise reduction cavity 4 into a noise reduction functional cavity 41 and a variable cavity 42. The noise reduction functional cavity 41 is communicated with the occiput 1 through the micropores 31;

[0050] A driving mechanism 5, which drives the isolation film 6 to change the volumes of the divided noise reduction functional cavity 41 and variable cavity 42.

[0051] In this embodiment, the specific structure of the adjusting device is described. The adjusting device includes an isolation membrane 6 and a driving mechanism 5. The isolation membrane 6 is disposed inside the noise reduction cavity 4, dividing the noise reduction cavity 4 into a noise reduction functional cavity 41 and a variable cavity 42. The noise reduction functional cavity 41 communicates with the occipital part 1 through micropores 31. The driving mechanism 5 is used to drive the isolation membrane 6 to change the volumes of the noise reduction functional cavity 41 and the variable cavity 42. By driving the isolation membrane 6 with the driving mechanism 5 to change the size of the noise reduction functional cavity 41, the frequency of sound absorption can be adjusted, and the adjustment method is simple, convenient and fast.

[0052] In some alternative embodiments, the driving mechanism 5 is an air pump. The air pump is connected to the variable cavity 42 through a pipeline. By changing the volume of the air inside the variable cavity 42, the position of the isolation membrane 6 is changed to adjust the volume of the noise reduction functional cavity 41.

[0053] In this embodiment, the driving mechanism 5 is an air pump. The air pump is connected to the variable cavity 42 through a pipeline. The isolation membrane 6 divides the noise reduction cavity 4 into a noise reduction functional cavity 41 and a variable cavity 42. By inflating or deflating the variable cavity 42 with the air pump, the volume of the variable cavity 42 can be changed, and then the position of the isolation membrane 6 can be changed to adjust the volume of the noise reduction functional cavity 41 and the frequency of sound absorption. The implementation method is simple and convenient for design and manufacture.

[0054] In some alternative embodiments, the air pump is used to be connected to the vehicle-mounted energy supply device through a circuit. The vehicle-mounted energy supply device is controlled by the vehicle-mounted ECU and receives the instructions of the vehicle-mounted ECU to perform inflation or deflation.

[0055] In this embodiment, the air pump is connected to the vehicle-mounted energy supply device through a circuit. The vehicle-mounted energy supply device is controlled by the vehicle-mounted ECU. The vehicle-mounted energy supply device receives the instructions of the vehicle-mounted ECU to perform inflation or deflation, without the need to use other control devices, further simplifying the operation process, which is convenient and fast.

[0056] In this example, the motor speed signal can be directly collected by the vehicle-mounted ECU, and through calculated to obtain the target frequency, and then according to , where , , directly calculate the functional volume of the noise reduction cavity 4, that is, the volume of the noise reduction functional cavity 41, convert the required volume of the noise reduction functional cavity 41 into an electrical signal, and transmit it to the vehicle-mounted energy supply device to perform the corresponding inflation or deflation operation.

[0057] As Figures 1-3 shown, in some alternative embodiments, a wrapping part is provided outside the noise reduction cavity 4. The wrapping part is connected to the occipital part 1 to form an accommodation cavity. The micro-perforated plate 3 and the noise reduction cavity 4 are both disposed in the accommodation cavity.

[0058] In this embodiment, a wrapping portion is provided outside the noise reduction cavity 4. The wrapping portion is connected to the pillow portion 1 to form a receiving cavity. The micro-perforated plate 3 and the noise reduction cavity 4 are arranged in the receiving cavity to wrap the micro-perforated plate 3 and the noise reduction cavity 4, which can play a certain protective role for the micro-perforated plate 3 and the noise reduction cavity 4, and is more in line with the design shape of the vehicle headrest, and has better comfort.

[0059] In this example, the materials of the wrapping portion and the pillow portion 1 are both sponge, which further improves the comfort.

[0060] Such as Figures 1-3 shown, in some alternative embodiments, a plurality of through holes 2 are formed in the pillow portion 1. The through holes 2 communicate with the micro-holes 31, and the hole neck directions of the through holes 2 and the micro-holes 31 are the same.

[0061] In this embodiment, a plurality of through holes 2 are formed in the pillow portion 1 to communicate the through holes 2 with the micro-holes 31, and the hole neck directions of the through holes 2 and the micro-holes 31 are the same, which can more conveniently transmit noise into the noise reduction cavity 4 through the through holes 2. Forming a plurality of through holes 2 in the pillow portion 1 can also improve the experience of the passengers and improve the comfort.

[0062] Such as Figures 1-4 shown, on the one hand, a noise elimination method is provided, which is implemented by using the above-mentioned vehicle headrest for noise elimination, and includes the following steps:

[0063] Determine the target frequency according to the motor speed;

[0064] Determine the target volume required for the noise reduction cavity 4 according to the target frequency;

[0065] Adjust the functional volume of the noise reduction cavity 4 according to the target volume required for the noise reduction cavity 4 to adjust the noise elimination frequency.

[0066] When using the vehicle headrest for noise elimination, a plurality of micro-holes 31 with the hole neck direction perpendicular to the plane direction of the micro-perforated plate 3 are formed in the micro-perforated plate 3. The pillow portion 1 is arranged on one side of the micro-perforated plate 3 and communicates with the micro-holes 31. The noise reduction cavity 4 is arranged on the other side of the micro-perforated plate 3 and communicates with the pillow portion 1 through the micro-holes 31. The resonance absorber principle is used for noise elimination. By adjusting the device to change the functional volume of the noise reduction cavity 4 according to the target frequency determined by the motor speed, the noise elimination frequency is adjusted. The adjustment method is simple, convenient and fast. It solves the problems in the prior art that it is difficult to perform active adjustment to cope with different frequency noises or the active adjustment structure is complex.

[0067] In some alternative embodiments, according to the formula: , , , , determine the target volume required for the noise reduction cavity 4;

[0068] Among them, is the target frequency, is the sound speed, n is the number of micro-holes 31, s is the cross-sectional area of a single micro-hole 31, is the effective length of the micro-hole 31, V is the target volume of the noise reduction cavity 4, t is the thickness of the micro-perforated plate 3, is the inherent calculated value of the micro-perforated plate 3, d is the opening diameter of the micro-hole 31, B is the center distance between adjacent micro-holes 31, and D is the average depth of the target volume of the noise reduction cavity 4.

[0069] In this embodiment, the principle formula of the micro-perforated plate 3 using a resonance absorber is , where , , , is the target frequency, is the sound speed, n is the number of micro-holes 31, s is the cross-sectional area of a single micro-hole 31, is the effective length of the micro-hole 31, V is the functional volume of the target of the noise reduction cavity 4, t is the thickness of the micro-perforated plate 3, is the inherent calculated value of the micro-perforated plate 3, d is the opening diameter of the micro-hole 31, B is the center distance between adjacent micro-holes 31, and D is the average depth of the functional volume of the noise reduction cavity 4. In this solution, except for are all fixed values, is only affected by the change of D. The functional volume V of the noise reduction cavity 4 is equal to the area of the micro-perforated plate 3 multiplied by the average depth D of the functional volume of the noise reduction cavity 4. The area of the micro-perforated plate 3 is a fixed value. Therefore, by adjusting the device to change the functional volume V of the noise reduction cavity 4 according to the target frequency, the frequency of sound absorption can be adjusted. The adjustment method is simple and easy to implement.

[0070] Such as Figure 5 shown, in this example, the micro-perforated plate 3 changes the functional volume V of the noise reduction cavity 4, and the change in the sound absorption ability is referred to Figure 5 . Changing the functional volume V of the noise reduction cavity 4 can change the sound absorption peak frequency. As long as this frequency can follow the excitation source, the purpose of active control can be achieved.

[0071] Such as Figures 1-4 shown, on the one hand, a vehicle seat is provided, which includes the above-mentioned vehicle headrest for sound absorption.

[0072] When using this vehicle seat, multiple micro-holes 31 with the hole neck direction perpendicular to the plane direction of the micro-perforated plate 3 are provided on the micro-perforated plate 3 for noise reduction of the vehicle headrest. The pillow part 1 is arranged on one side of the micro-perforated plate 3 and communicated with the micro-holes 31. The noise reduction cavity 4 is arranged on the other side of the micro-perforated plate 3 and communicated with the pillow part 1 through the micro-holes 31, and noise reduction is carried out by using the principle of a resonance absorber. By collecting the motor speed signal, through calculating the target frequency, the principle formula of the micro-perforated plate 3 using the resonance absorber is , where , , , is the target frequency, is the speed of sound, n is the number of the micro-holes 31, s is the cross-sectional area of a single micro-hole 31, is the effective length of the micro-hole 31, V is the functional volume of the noise reduction cavity 4, t is the thickness of the micro-perforated plate 3, is the inherent calculated value of the micro-perforated plate 3, d is the opening diameter of the micro-hole 31, B is the center distance between adjacent micro-holes 31, D is the average depth of the functional volume of the noise reduction cavity 4. In this solution, except for are all fixed values, only changes with the change of D. The functional volume V of the noise reduction cavity 4 is equal to the area of the micro-perforated plate 3 multiplied by the average depth D of the functional volume of the noise reduction cavity 4. The area of the micro-perforated plate 3 is a fixed value. Therefore, by adjusting the device to change the functional volume V of the noise reduction cavity 4 according to the target frequency, the frequency of noise reduction can be adjusted. By adjusting the device to change the functional volume V of the noise reduction cavity 4 according to the target frequency to adjust the frequency of noise reduction, the adjustment method is simple, convenient and fast. It solves the problems in the prior art that it is difficult to carry out active adjustment to cope with noises of different frequencies or the active adjustment structure is complex.

[0073] Such as Figures 1-4 shown, on the other hand, a vehicle is provided, which includes the above-mentioned vehicle seat.

[0074] When using this vehicle, multiple micro-holes 31 with the hole neck direction perpendicular to the plane direction of the micro-perforated plate 3 are provided on the micro-perforated plate 3. The pillow part 1 is arranged on one side of the micro-perforated plate 3 and communicated with the micro-holes 31. The noise reduction cavity 4 is arranged on the other side of the micro-perforated plate 3 and communicated with the pillow part 1 through the micro-holes 31, and noise reduction is carried out by using the principle of a resonance absorber. By collecting the motor speed signal, through calculating the target frequency, the principle formula of the micro-perforated plate 3 using the resonance absorber is , where , , , is the target frequency, is the speed of sound, n is the number of micro-holes 31, s is the cross-sectional area of a single micro-hole 31, is the effective length of the micro-hole 31, V is the functional volume of the noise reduction cavity 4, t is the thickness of the micro-perforated plate 3, is the inherent calculated value of the micro-perforated plate 3, d is the opening diameter of the micro-hole 31, B is the center distance between adjacent micro-holes 31, D is the average depth of the functional volume of the noise reduction cavity 4. In this solution, except for are all fixed values, only changes with the change of D. The functional volume V of the noise reduction cavity 4 is equal to the area of the micro-perforated plate 3 multiplied by the average depth D of the functional volume of the noise reduction cavity 4. The area of the micro-perforated plate 3 is a fixed value. Therefore, by adjusting the device to change the functional volume V of the noise reduction cavity 4 according to the target frequency, the frequency of sound absorption can be adjusted. By adjusting the device to change the functional volume V of the noise reduction cavity 4 according to the target frequency to adjust the frequency of sound absorption, the adjustment method is simple, convenient and fast. It solves the problems in the prior art that it is difficult to perform active adjustment to cope with different frequency noises or the active adjustment structure is complex.

[0075] In summary, the present application provides a vehicle headrest, vehicle seat, vehicle and sound absorption method for sound absorption. When using the vehicle headrest for sound absorption, a plurality of micro-holes 31 with the hole neck direction perpendicular to the plane direction of the micro-perforated plate 3 are opened on the micro-perforated plate 3. The pillow part 1 is arranged on one side of the micro-perforated plate 3 and communicated with the micro-holes 31. The noise reduction cavity 4 is arranged on the other side of the micro-perforated plate 3 and communicated with the pillow part 1 through the micro-holes 31. The principle of the resonance absorber is used for sound absorption. By collecting the motor speed signal, through calculating the target frequency, the principle formula of the micro-perforated plate 3 using the resonance absorber is , where , , , is the target frequency, is the speed of sound, n is the number of micro-holes 31, s is the cross-sectional area of a single micro-hole 31, is the effective length of the micro-hole 31, V is the functional volume of the noise reduction cavity 4, t is the thickness of the micro-perforated plate 3, is the inherent calculated value of the micro-perforated plate 3, d is the opening diameter of the micro-hole 31, B is the center distance between adjacent micro-holes 31, D is the average depth of the functional volume of the noise reduction cavity 4. In this solution, except for are all fixed values, It only changes with the change of D. The functional volume V of the noise reduction cavity 4 is equal to the area of the micro-perforated plate 3 multiplied by the average depth D of the functional volume of the noise reduction cavity 4. Since the area of the micro-perforated plate 3 is a fixed value, the functional volume V of the noise reduction cavity 4 is changed according to the target frequency by the adjusting device. The adjusting device includes an isolation membrane 6 and a driving mechanism 5. The isolation membrane 6 is arranged inside the noise reduction cavity 4, dividing the noise reduction cavity 4 into a noise reduction functional cavity 41 and a variable cavity 42. The noise reduction functional cavity 41 communicates with the occipital part 1 through micropores 31. The driving mechanism 5 is used to drive the isolation membrane 6 to divide the volumes of the noise reduction functional cavity 41 and the variable cavity 42. By driving the isolation membrane 6 by the driving mechanism 5 to change the size of the noise reduction functional cavity 41, the frequency of sound absorption is adjusted. The driving mechanism 5 is an air pump, and the air pump is connected to the variable cavity 42 through a pipeline. The isolation membrane 6 divides the noise reduction cavity 4 into a noise reduction functional cavity 41 and a variable cavity 42. By inflating or deflating the variable cavity 42 through the air pump, the volume of the variable cavity 42 can be changed, and then the volume of the noise reduction functional cavity 41 can be changed. The air pump is connected to the vehicle-mounted energy supply device through a circuit. The vehicle-mounted energy supply device is controlled by the vehicle-mounted ECU. The vehicle-mounted energy supply device receives the instruction of the vehicle-mounted ECU to perform inflation or deflation, and the operation is more convenient. By the adjusting device, the functional volume V of the noise reduction cavity 4 is changed according to the target frequency, and the frequency of sound absorption is adjusted. The adjustment method is simple, convenient and fast. It solves the problems in the prior art that it is difficult to perform active adjustment to cope with noises of different frequencies or the active adjustment structure is complex.

[0076] In the description of the present application, it should be noted that the orientation or positional relationship indicated by terms such as "upper" and "lower" is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, so it cannot be understood as a limitation to the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0077] It should be noted that in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising said element.

[0078] The above are only specific embodiments of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application will not be limited to these embodiments shown herein, but rather will conform to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A vehicle headrest for noise reduction, characterized in that, Comprising: A micro-perforated plate (3) with a plurality of micropores (31) formed thereon; A pillow part (1) disposed on one side of the micro-perforated plate (3), the pillow part (1) communicating with the micropores (31), a plurality of through holes (2) being formed in the pillow part (1), the through holes (2) communicating with the micropores (31), and the through holes (2) and the micropores (31) having the same hole opening direction; A noise reduction cavity (4) disposed on the other side of the micro-perforated plate (3), the noise reduction cavity (4) communicating with the pillow part (1) through the micropores (31); An adjusting device for adjusting the functional volume of the noise reduction cavity (4) according to a target frequency determined by the motor speed to adjust the sound absorption frequency.

2. The vehicle headrest for noise reduction according to claim 1, wherein, The adjusting device includes: An isolation film (6) disposed inside the noise reduction cavity (4), dividing the noise reduction cavity (4) into a noise reduction functional cavity (41) and a variable cavity (42), the noise reduction functional cavity (41) communicating with the pillow part (1) through the micropores (31); A driving mechanism (5) for driving the isolation film (6) to change the volumes of the noise reduction functional cavity (41) and the variable cavity (42).

3. The vehicle headrest for noise reduction according to claim 2, characterized in that, The driving mechanism (5) is an air pump, the air pump being connected to the variable cavity (42) through a pipeline, and by changing the air volume inside the variable cavity (42), the position of the isolation film (6) is changed to adjust the volume of the noise reduction functional cavity (41).

4. The vehicle headrest for noise reduction according to claim 3, wherein, The air pump is used to be connected to a vehicle-mounted power supply device through a circuit, the vehicle-mounted power supply device being controlled by a vehicle-mounted ECU and receiving instructions from the vehicle-mounted ECU to perform inflation or deflation.

5. The vehicle headrest for noise reduction according to claim 1, characterized in that, A wrapping part is provided outside the noise reduction cavity (4), the wrapping part being connected to the pillow part (1) to form a receiving cavity, and the micro-perforated plate (3) and the noise reduction cavity (4) are both disposed in the receiving cavity.

6. A sound attenuation method, characterized in that, Implementing by using a vehicle-mounted headrest for sound absorption according to any one of claims 1-5, including the following steps: Determining a target frequency according to the motor speed; Determining a target volume required for the noise reduction cavity (4) according to the target frequency; Adjusting the functional volume of the noise reduction cavity (4) according to the target volume required for the noise reduction cavity (4) to adjust the sound absorption frequency.

7. The noise reduction method according to claim 6, characterized in that, According to the formula: , , , to determine the target volume required for the noise reduction cavity (4); Wherein, is the target frequency, is the speed of sound, n is the number of micro-holes (31), s is the cross-sectional area of a single micro-hole (31), is the effective length of the micro-hole (31), V is the target volume of the noise reduction cavity (4), t is the thickness of the micro-perforated panel (3), is the inherent calculated value of the micro-perforated panel (3), d is the opening diameter of the micro-hole (31), B is the center distance between adjacent micro-holes (31), D is the average depth of the target volume of the noise reduction cavity (4), is an intermediate parameter.

8. A vehicle seat, characterized in that, Including a vehicle-mounted headrest for sound absorption according to any one of claims 1-5.

9. A vehicle, characterized in that, Including a vehicle seat according to claim 8.

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