Concave type expansion tube
By setting an annular groove on the side wall of the sound wave channel of the MEMS speaker to enhance sound interference and reflection, the ultrasonic noise problem of MEMS speakers is solved, and the noise reduction effect at specific frequencies is achieved, protecting human health and improving chip compatibility.
Patent Information
- Application Number
- CN202422143444.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-02
- Publication Date
- 2025-09-05
- Estimated Expiration
- 2034-09-02
AI Technical Summary
MEMS speakers generate sharp ultrasonic noise at the driving frequency, affecting human health and chip compatibility. The prior art is difficult to achieve 32dB noise reduction effect at a specific frequency 37.4kHz without affecting the propagation of sound waves below 30kHz frequency.
A recessed expansion tube is designed. By setting multiple annular grooves on the side walls of the sound wave channel, the sound waves generate cross-sectional changes at each groove, enhancing interference and reflection, and achieving noise reduction effect.
Without affecting the propagation of sound waves in other frequency bands, the recessed expansion tube achieves 32dB at the frequency of 37.4KHz, reducing ultrasonic noise, protecting human health and improving chip compatibility.
Smart Images
Figure CN223309955U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of acoustics, in particular to a concave expansion tube. Background Art
[0002] Currently, microelectromechanical systems (MEMS) technology, which uses semiconductor and bulk silicon micromachining to create microstructures, is widely used in the manufacture of various chips, such as sensors, microphones, and accelerometers. MEMS speakers offer excellent sound quality and low power consumption in a very small size, and are widely used in smartphones, wearable smart devices, and automobiles.
[0003] MEMS speakers operate at ultrasonic frequencies. Mechanical drive generates sharp ultrasonic noise at these frequencies, with energy 40-50dB higher than that of adjacent frequency bands. This noise energy can be harmful to the human body and affect chip compatibility. Currently, it's impossible to achieve a 32dB noise reduction effect at a specific frequency of 37.4kHz without affecting sound wave propagation below 30kHz. Utility Model Content
[0004] The purpose of the utility model is to provide a concave expansion tube for improving the noise reduction effect of a sound chip.
[0005] In order to achieve the above-mentioned purpose, the present invention provides the following technical solutions: a concave expansion tube, comprising:
[0006] Multiple expansion pieces are arranged in sequence from top to bottom, and two adjacent expansion pieces are correspondingly engaged and snap-fitted. A window for testing the acoustics of the chip is opened in the central area of each expansion piece. Multiple expansion pieces form a channel at the window, and there are multiple annular grooves on the side walls of the channel. The multiple annular grooves are arranged in sequence from top to bottom along the extension direction of the channel.
[0007] Optionally, in the above-mentioned recessed expansion tube, the cross-sectional shape of the annular groove includes T-shape, rectangle or circle.
[0008] Optionally, in the above-mentioned recessed expansion tube, the depth a of the annular groove embedded in the expansion piece is 0.8 mm to 1.5 mm.
[0009] Optionally, in the above-mentioned recessed expansion tube, a height b of the annular groove along the vertical direction is 0.8 mm to 1.5 mm.
[0010] Optionally, in the above-mentioned recessed expansion tube, the window includes a rectangle or a circle.
[0011] Optionally, in the above-mentioned recessed expansion tube, the width c of the window is 8 mm to 12 mm.
[0012] Optionally, in the above-mentioned recessed expansion tube, the connecting seam between two adjacent expansion pieces that are engaged and clamped is stepped.
[0013] Optionally, in the above-mentioned recessed expansion tube, after the plurality of expansion pieces are correspondingly engaged and snap-fitted, both the upper surface and the lower surface along the extension direction of the channel comprise a plane.
[0014] Optionally, in the above-mentioned recessed expansion tube, a stacking height H of the plurality of expansion pieces along the channel direction is 4 mm to 12 mm.
[0015] Compared with the existing technology, when adopting the above technical solution, multiple corresponding interlocking expansion plates are placed on the chip, and multiple annular grooves are set through the side walls of the channel. Without affecting the propagation of sound waves in other frequency bands, a cross-sectional mutation occurs at each annular groove when the sound wave passes through the channel, so that the sound wave obtains multiple cross-sectional mutations, enhancing the interference and reflection phenomenon of the sound wave at the annular groove of the channel, so as to achieve a noise reduction effect. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:
[0017] Figure 1 This is a schematic diagram of the overall structure of a recessed expansion tube provided in an embodiment of the present utility model;
[0018] Figure 2 for Figure 1 Assembly diagram of
[0019] Figure 3 for Figure 2 The local structural cross-section diagram in
[0020] Figure 4 for Figure 1 The overall structural cross-section diagram;
[0021] Figure 5 for Figure 4 Cross-sectional dimension drawing;
[0022] Figure 6 for Figure 1 Installation diagram;
[0023] Figure 7 This is a sound pressure level response diagram at a point 5 cm vertically from the surface of a MEMS speaker when a recessed expansion tube provided in an embodiment of the present invention is installed and when it is not installed.
[0024] Reference numerals:
[0025] 1-expansion piece; 11-window; 2-channel; 3-annular groove; 4-connecting seam; 5-chip. DETAILED DESCRIPTION
[0026] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.
[0027] It should be noted that when an element is referred to as being “fixed on” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or indirectly connected to the other element.
[0028] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of this utility model, "plurality" means two or more, unless otherwise specifically defined. "Several" means one or more, unless otherwise specifically defined.
[0029] In the description of the present invention, it should be understood that the terms "up", "down", "front", "back", "left", "right", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.
[0030] In the description of this utility model, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and can refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.
[0031] like Figure 1-Figure 7 As shown, an embodiment of the present invention provides a recessed expansion tube, which includes: an expansion piece 1.
[0032] Among them, multiple expansion pieces 1 are arranged in sequence from top to bottom, and two adjacent expansion pieces 1 are correspondingly engaged and snap-fitted. A window 11 for testing the acoustics of the chip 5 is opened in the central area of each expansion piece 1. Multiple expansion pieces 1 form a channel 2 at the window 11, and a plurality of annular grooves 3 are provided on the side wall of the channel 2. The plurality of annular grooves 3 are arranged in sequence from top to bottom along the extension direction of the channel.
[0033] When implementing it specifically, Figure 1 As shown, a plurality of correspondingly engaged expansion pieces 1 are placed on the chip 5, and a plurality of annular grooves 3 are set through the side wall of the channel 2. Without affecting the propagation of sound waves in other frequency bands, a cross-sectional mutation occurs at each annular groove 3 when the sound wave passes through the channel 2, so that the sound wave obtains multiple cross-sectional mutations, thereby enhancing the interference and reflection phenomenon of the sound wave at the annular groove 3 of the channel 2, so as to achieve a noise reduction effect.
[0034] like Figure 7 As shown, it should be noted that curve A in the figure shows the change in sound pressure level response when the recessed expansion tube is not added, and curve B shows the change in sound pressure level response after the recessed expansion tube is added. Each annular groove 3 is connected at the corner, and the cross-sectional mutation generated by forming the side wall of the channel 2 only in the annular groove 3, and the other side walls of the channel 2 are all smooth. Without affecting the propagation of sound waves in other frequency bands, multiple groups of expansion plates 1 are arranged in a snap-fit manner, that is, multiple annular grooves 3 are formed in the vertical direction in the channel 2 to provide discontinuity for the acoustic impedance. The sound waves produce multiple interferences, reflections and sound energy dissipation at the cross-sectional mutation points, so that the recessed expansion tube achieves 32dB of attenuation at a frequency of 37.4KHz, achieving a noise reduction effect, and basically no attenuation below 30KHz, avoiding the impact on the propagation of sound waves in other frequency bands.
[0035] like Figure 3 and Figure 4 As shown, specifically, in this embodiment, the cross-sectional shape of the annular groove 3 includes a T-shape, a rectangle, or a circle. The cross-sectional shape of the annular groove 3 can be T-shaped, rectangular, circular, or other polygonal shapes, without specific limitation herein, as long as the annular groove 3 can provide a cross-sectional mutation for the sidewall of the channel 2. The recessed expansion tube creates a discontinuity in acoustic impedance through the cross-sectional mutation of the sidewall of the channel 2, causing the sound waves to interfere and reflect multiple times at the cross-sectional mutation to achieve acoustic energy dissipation, thereby enhancing the acoustic wave reflection and interference effect and the acoustic energy dissipation effect, thereby ensuring the noise reduction effect of the recessed expansion tube.
[0036] like Figure 5As shown, specifically, in this embodiment, the depth a of the annular groove 3 embedded in the expansion piece 1 is 0.8 mm to 1.5 mm. The depth a of the annular groove 3 embedded in the expansion piece 1 can be 0.8 mm, 1 mm, 1.35 mm, 1.5 mm, etc. There is no specific limitation on the depth a of the annular groove 3 embedded in the expansion piece 1, as long as the depth a of the annular groove 3 formed satisfies the dissipation of acoustic energy.
[0037] like Figure 5 As shown, specifically, in this embodiment, the height b of the annular groove 3 along the vertical direction is 0.8 mm to 1.5 mm. The height b of the annular groove 3 along the vertical direction can be 0.8 mm, 1 mm, 1.3 mm, 1.5 mm, etc. There is no specific limitation on the height b of the annular groove 3 along the vertical direction, as long as the height b of the annular groove 3 formed satisfies the dissipation of acoustic energy.
[0038] like Figure 6 As shown, specifically, in this embodiment, the window 11 includes a rectangular or circular shape. The window 11 on the expansion piece can be set to a rectangular, circular or other polygonal shape. The shape of the window 11 is not specifically limited here, as long as the channel 2 formed by the window 11 can allow the sound waves of the chip 5 to pass through.
[0039] like Figure 5 As shown, specifically, in this embodiment, the width c of the window 11 is 8 mm to 12 mm. When the window 11 is rectangular, the width c of the window 11 is the side length of the rectangle. In this case, the width c of the window 11 can be 8 mm, 9.5 mm, 10 mm, 12 mm, etc. When the window 11 is circular, the width c of the window 11 is the diameter of the circle. In this case, the width c of the window 11 can be 8 mm, 9 mm, 10 mm, 12 mm, etc. There is no specific limitation on the width c of the window 11 as long as the channel 2 formed by the window 11 can allow the sound waves of the chip 5 to pass through.
[0040] like Figure 5 As shown, specifically, in this embodiment, the connecting seam 4 between the adjacent expansion pieces 1 is stepped. The connecting seam 4 can be stepped, wavy, or in other shapes, without specific limitation, as long as the corresponding engagement between the two adjacent expansion pieces 1 is achieved. The different shapes of the connecting seam 4 improve the stability and reliability of the connection structure between the two adjacent expansion pieces 1.
[0041] like Figure 1 、 Figure 5 and Figure 6As shown, specifically, in this embodiment, the upper and lower surfaces of the plurality of expansion pieces 1 corresponding to the extension direction of the channel 2 after being engaged and snapped together are both flat. Specifically, one of the upper and lower surfaces of the plurality of expansion pieces 1 corresponding to the extension direction of the channel 2 after being engaged and snapped together is a flat surface, or both the upper and lower surfaces of the plurality of expansion pieces 1 corresponding to the extension direction of the channel 2 after being engaged and snapped together are flat surfaces. The flat surfaces are assembled in contact with the surface of the chip 5, thereby improving the flatness of the assembly surface between the recessed expansion tube and the chip 5 and reducing vibration of the recessed expansion tube on the chip 5 during operation.
[0042] like Figure 5 As shown, specifically, in this embodiment, the stacking height H of the plurality of expansion pieces 1 along the direction of the channel 2 is within a range of 4 mm to 12 mm. The stacking height H of the plurality of expansion pieces 1 along the direction of the channel 2 can be 4 mm, 8 mm, 10 mm, 12 mm, etc., which is not specifically limited here.
[0043] like Figure 5 As shown, preferably, in this embodiment, the noise reduction characteristics of the recessed expansion tube are related to its geometric dimensions. Through structural design, it can attenuate 37.4kHz noise by 32dB. At this time, the height b of the annular groove 3 is 1.0mm, and the width a is 0.5mm. When the cross-sectional shape of the annular groove 3 is T-shaped, d is 0.2mm, the width of the neck is e is 0.4mm, and the structural wall thickness is f is 1.5mm; the width m of the connecting seam 4 of the expansion sheet 1 is 0.75mm, and n is 0.8mm at the connecting seam 4; the size p of the clamping part of each layer of expansion sheet 1 is 0.5mm, the total thickness D of each layer of expansion sheet 1 is 2.4mm, and the total height L of two adjacent expansion sheets 1 is 4mm; after the structural assembly is completed, the total height H is 12mm, the width W is 14.8mm, and the width c of the window 11 (i.e., the size of the expansion cavity entrance) is 10mm.
[0044] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.
[0045] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.
Claims
1. A concave expansion tube, characterized in that: include: A plurality of expansion sheets are arranged in sequence from top to bottom, and two adjacent expansion sheets are correspondingly engaged and snap-fitted. A window for testing the acoustics of the chip is opened in the central area of each expansion sheet. The plurality of expansion sheets form a channel at the window, and a plurality of annular grooves are provided on the side walls of the channel. The plurality of annular grooves are arranged in sequence from top to bottom along the extension direction of the channel.
2. The recessed expansion tube according to claim 1, characterized in that: The cross-sectional shape of the annular groove includes T-shape, rectangle or circle.
3. The recessed expansion tube according to claim 1, characterized in that: The depth a of the annular groove embedded in the expansion piece is 0.8 mm to 1.5 mm.
4. The recessed expansion tube according to claim 1, characterized in that: The height b of the annular groove along the vertical direction is 0.8 mm to 1.5 mm.
5. The recessed expansion tube according to claim 1, characterized in that: The window includes a rectangle or a circle.
6. The recessed expansion tube according to claim 1, characterized in that: The width c of the window is 8 mm to 12 mm.
7. The recessed expansion tube according to claim 1, characterized in that: The connecting seam between two adjacent expansion pieces is in a stepped shape.
8. The recessed expansion tube according to claim 1, characterized in that: After the plurality of expansion pieces are correspondingly engaged and snap-fitted, the upper surfaces and lower surfaces along the extension direction of the channel both comprise planes.
9. The recessed expansion tube according to claim 1, characterized in that: The stacking height H of the plurality of expansion pieces along the channel direction is 4 mm to 12 mm.