Noise reduction pipe

Abstract

The utility model belongs to the field of acoustics, solves the problem of how to improve the noise reduction effect of a noise reduction pipe with an expansion cavity, and relates to a noise reduction pipe which comprises a pipe body and a channel formed in the pipe body, the channel penetrates through the pipe body and is provided with a first end and a second end, and the inner wall of the pipe body is provided with the expansion cavity formed in an inward concave mode. The expansion cavity comprises a plurality of transverse grooves distributed in the direction from the first end to the second end, and at least two transverse grooves are communicated with each other. Because the discontinuity of acoustic impedance is created through the sudden change of the section of the expansion cavity structure, the noise reduction effect is achieved by utilizing the characteristics of interference, reflection and the like generated by sound waves at the sudden change of the section. And through the design that the transverse grooves are communicated, the sound wave dissipation effect is enhanced. And the noise reduction pipe can achieve a specific ultrasonic frequency noise reduction effect through parameter design, and propagation of sound waves in other frequency bands is not blocked.

Description

Technical Field

[0001] This utility model belongs to the field of acoustics, specifically relating to a noise reduction tube. Background Technology

[0002] Microelectromechanical (MEMS) loudspeakers are audio output devices that convert electrical signals into sound signals using MEMS technology. Compared to traditional electromagnetic loudspeakers, they are smaller and more efficient. However, MEMS loudspeakers suffer from ultrasonic noise due to their mechanical drive. The noise energy in the ultrasonic frequency band can be harmful to the human body and affect chip compatibility. Currently, it is not possible to achieve noise reduction at a specific ultrasonic frequency without affecting the propagation of sound waves in other frequency bands. Utility Model Content

[0003] The purpose of this invention is to provide a noise-reducing tube that solves the problem of how to improve the noise reduction effect of a noise-reducing tube with an expansion cavity.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0005] This utility model provides a noise reduction tube, including a tube body and a channel formed in the tube body. The channel penetrates the tube body and has a first end and a second end. The inner wall of the tube body has an expansion cavity formed by an inward concavity. The expansion cavity includes multiple transverse grooves distributed along the direction from the first end to the second end, and at least two of the transverse grooves are interconnected.

[0006] Preferably, the two connected transverse grooves are connected by a vertical groove that extends in the direction from the first end to the second end.

[0007] Preferably, the two connected transverse grooves are connected by a vertical groove, and the connected transverse grooves and the corresponding vertical grooves together form a spiral structure extending from the center to the edge of a region on the inner wall of the tube.

[0008] Furthermore, the width of the horizontal groove is the same as that of the vertical groove.

[0009] Preferably, there are two axial cutting lines that divide the wall of the tube into two equal parts along the two axial cutting lines, and the expansion cavities in these two parts are asymmetrical.

[0010] Preferably, there exists a transverse groove that is not connected to other transverse grooves.

[0011] Preferably, the tube body has a first single piece and a second single piece, which are connected by a snap-fit ​​structure, the snap-fit ​​structure including a protrusion in one of the first single piece and a recess in the other.

[0012] Furthermore, the horizontal grooves on the first single piece are connected by vertical grooves, and the horizontal grooves and the corresponding vertical grooves together form a spiral structure extending from the center to the edge of a region on the inner wall of the tube.

[0013] Preferably, the cross-sectional shape and size of the channel from the first end to the second end remain unchanged.

[0014] Preferably, the channel portion at the first end is used to mount the object to be noise-reduced, and the inner wall of the channel at the first end is flush with the outer periphery of the object to be noise-reduced.

[0015] Due to the application of the above technical solution, this utility model has the following advantages compared with the prior art:

[0016] This invention's noise-reducing tube achieves noise reduction by creating a discontinuity in acoustic impedance through abrupt changes in the cross-sectional area of ​​the expansion cavity. This discontinuity is exploited by the interference and reflection of sound waves at these points. The interconnected transverse slots enhance sound wave dissipation. Furthermore, through parameter design, the tube can achieve noise reduction at specific ultrasonic frequencies without obstructing the propagation of sound waves in other frequency bands. Attached Figure Description

[0017] The following sections will describe some specific embodiments of the present invention in a detailed manner by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or components. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0018] Figure 1 This is a schematic diagram of a preferred embodiment of the present invention combined with a chip;

[0019] Figure 2 yes Figure 1 A schematic diagram showing the disassembly of the noise reduction tube;

[0020] Figure 3 This is a schematic diagram showing the expansion cavity on the inner surface of the noise-canceling tube after it has been disassembled;

[0021] Figure 4 This is a schematic diagram of transmission loss at different frequencies;

[0022] The reference numerals in the attached figures are explained as follows:

[0023] 1. Tube body; 11. Expansion cavity; 111. Horizontal groove; 112. Vertical groove; 12. First single piece; 13. Second single piece; 14. Snap-fit ​​structure; 141. Protrusion; 142. Recess; 2. Channel; 21. First end; 22. Second end; 3. Chip. Detailed Implementation

[0024] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0025] like Figure 1 The noise-reducing tube shown includes a tube body 1, which contains a channel 2. The channel 2 has a first end 21 and a second end 22. The size and cross-sectional shape of the channel 2 remain constant from the first end 21 to the second end 22. The first end 21 is close to the chip 3, and the channel 2 extends from the first end 21 to the second end 22. The tube body 1 is composed of two parts: a first monolith 12 and a second monolith 13.

[0026] like Figure 3 The inner surface of the first single piece 12 is a spiral, labyrinth-like expansion cavity 11, including a horizontal groove 111 and a vertical groove 112. The vertical groove 112 can be seen as connecting the horizontal groove 111. The horizontal groove 111 extends along the cross-section of the tube body 1, and the vertical groove 112 extends axially (in the direction from the first end 21 to the second end 22). The inner surface of the first single piece 12 has a spiral labyrinth-like expansion tube structure. The inner surface of the second single piece 13 has an eight-layer conventional expansion tube structure connected in series. Figure 3 The tube body 1 is shown to have eight non-connected transverse grooves 111 distributed axially upwards, forming an expansion tube structure. The width and depth of the transverse grooves 111 and the vertical grooves 112 are the same.

[0027] The horizontal groove 111 may not strictly extend along the cross section of the pipe body 1, and the vertical groove 112 may not strictly extend along the axial direction of the pipe body 1. Furthermore, the width and depth of the horizontal groove 111 and the vertical groove 112 may be different.

[0028] like Figure 2 The first single piece 12 and the second single piece 13 are connected by a snap-fit ​​structure 14. The edges of the first single piece 12 and the second single piece 13 have protrusions 141 and recesses 142. The first single piece 12 and the second single piece 13 are connected by the protrusion 141 of one and the recess 142 of the other.

[0029] In specific implementation, such as Figure 1 As shown, the noise reduction tube is placed on the chip 3. The inner wall surface of the first end 21 of the channel 2 is flush with the perimeter of the chip 3, ensuring that there is no obstruction directly above the chip 3. Through the expansion cavity 11 set on the side wall of the channel 2, the sound wave produces a cross-sectional change at each transverse slot 111 when passing through the channel 2 without affecting the propagation of other frequency bands. This allows the sound wave to obtain multiple cross-sectional changes, enhancing interference and reflection phenomena to achieve the noise reduction effect.

[0030] Figure 4The simulation results of the transmission loss of the noise reduction tube provided in this embodiment show that the noise reduction tube can achieve a noise reduction effect of 19dB at a frequency of 47kHz, while having virtually no effect on other frequencies.

[0031] Expansion cavity structures are commonly used in reactive silencers. They create a discontinuity in acoustic impedance through abrupt changes in the cross-section of the tube 1, utilizing the interference and reflection characteristics of sound waves at these points to achieve noise reduction. A labyrinth expansion cavity design connects the expansion cavities on the first monolith 12, enhancing sound wave dissipation. The combination of the labyrinth expansion cavity 11 (first monolith 12) and the ordinary expansion cavity 11 (second monolith 13) breaks structural symmetry, suppresses structural resonance, and improves noise reduction. Parameter design allows the expansion tube to achieve noise reduction at specific ultrasonic frequencies without obstructing the propagation of sound waves in other frequency bands.

[0032] As for symmetry Figure 3 The diagram shows two axial tangent lines that divide the wall of tube 1 into two equal parts, with the expansion cavities 11 in these two parts being asymmetrical. In fact, in this example, dividing tube 1 into two parts along any two axial tangent lines results in asymmetrical expansion cavities 11 in these two parts. Furthermore, the two spiral regions on the first single piece 12 are also asymmetrical.

[0033] This invention addresses the shortcomings of existing technologies by providing a noise-reducing tube with ultrasonic noise reduction effect. In one example, it achieves a noise reduction effect of 19dB at a specific frequency of 47kHz without significantly affecting the propagation of sound waves in other frequency bands. This provides a solution to the specific high-frequency noise problem of microelectromechanical loudspeakers and offers a reference for the design of variable cross-section array structures.

[0034] The above embodiments are only for illustrating the technical concept and features of this utility model. Their purpose is to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be used to limit the protection scope of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be included within the protection scope of this utility model.

Claims

1. A noise-reducing tube, comprising a tube body (1) and a channel (2) formed within the tube body (1), the channel (2) penetrating the tube body (1) and having a first end (21) and a second end (22), wherein the inner wall of the tube body (1) has an inwardly formed expansion cavity (11), characterized in that, The expansion cavity (11) includes multiple transverse grooves (111) distributed along the direction from the first end (21) to the second end (22), and at least two of the transverse grooves (111) are interconnected.

2. The noise reduction tube according to claim 1, characterized in that: The two connected transverse grooves (111) are connected by a vertical groove (112) that extends in the direction from the first end (21) to the second end (22).

3. The noise reduction tube according to claim 1, characterized in that: The two connected transverse grooves (111) are connected by a vertical groove (112). The connected transverse grooves (111) and the corresponding vertical grooves (112) together form a spiral structure extending from the center of a region on the inner wall of the tube (1) to the edge.

4. The noise reduction tube according to claim 3, characterized in that: The width of the horizontal groove (111) is the same as that of the vertical groove (112).

5. The noise reduction tube according to claim 1, characterized in that: There are two axial cutting lines that divide the wall of the tube (1) into two parts along the two axial cutting lines, and the expansion cavities (11) on these two parts are asymmetrical.

6. The noise reduction tube according to claim 1, characterized in that: There exists a transverse groove (111) that is not connected to any other transverse groove (111).

7. The noise reduction tube according to claim 1, characterized in that: The tube body (1) has a first piece (12) and a second piece (13), the first piece (12) and the second piece (13) are connected by a snap-fit ​​structure (14), the snap-fit ​​structure (14) includes a protrusion (141) in one of the first piece (12) and a recess (142) in the other.

8. The noise reduction tube according to claim 7, characterized in that: The horizontal grooves (111) on the first single piece (12) are connected by vertical grooves (112), and the horizontal grooves (111) and the corresponding vertical grooves (112) together form a spiral structure extending from the center of a region of the inner wall of the tube (1) to the edge.

9. The noise reduction tube according to claim 1, characterized in that: The cross-sectional shape and size of the channel (2) from the first end (21) to the second end (22) remain unchanged.

10. The noise reduction tube according to claim 1, characterized in that: The channel (2) portion of the first end (21) is used to install the noise-reducing object, and the inner wall of the channel (2) of the first end (21) is flush with the outer periphery of the noise-reducing object.

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