A method for testing damping performance of a composite diaphragm of a headphone

Abstract

The application discloses a kind of earphone composite diaphragm sheet damping performance test methods, comprising the following steps: step S1, cutting sample piece;Step S2, clamping sample piece: along the length direction of sample piece, sample piece is folded, so that the two ends of sample piece are completely coincident, then the two ends of sample piece are coincident and clamped between two steel sheets;Step S3, install sample piece: the steel sheet with sample piece is clamped is placed on the clamp of universal tensile testing machine;Step S4, press test: start tensile testing machine, start press test, record the work value G1 in the process of tensile testing machine press, with the work value G2 in the process of tensile testing machine rebound, G1 and G2 difference is used to quantify the damping performance of earphone composite diaphragm sheet.The damping performance of earphone composite diaphragm sheet is evaluated and quantified by work loss, not only has the characteristics of convenient testing, short testing time, but also the evaluation of the damping performance of earphone composite diaphragm sheet is more accurate.

Description

Technical Field

[0001] This invention relates to a test method for composite diaphragms in headphones, specifically a method for testing the damping performance of composite diaphragms in headphones. Background Technology

[0002] While the damping performance of a simple adhesive layer can be tested using a rheometer, a composite diaphragm formed by two thin films sandwiching a 3-50 μm damping adhesive layer cannot be directly tested by a rheometer. In other words, existing rheometers cannot test the damping performance of composite diaphragms in headphones.

[0003] Currently, the testing method for the damping performance of composite diaphragms in headphones involves manufacturing the composite diaphragm into a finished headphone for testing. This testing process is quite lengthy, and the reliability of the test is reduced due to errors inherent in headphone manufacturing. Furthermore, the testing cycle is too long, ranging from two weeks to several months, which severely impacts the efficiency of the early-stage development of the diaphragm.

[0004] On May 14, 2021, the State Intellectual Property Office published patent document CN112798633A, which provides a microscopic testing method for damping performance. The method includes the following steps: A) processing the material to be tested into a micro / nano column; B) conducting a uniaxial compression experiment on the micro / nano column to obtain a stress-strain curve; C) using the stress at the elastic deformation stage on the stress-strain curve as the maximum load, conducting a periodic uniaxial compression experiment on the micro / nano column with equal stress amplitude to obtain an engineering stress-time curve and an engineering strain-time curve; D) calculating the damping coefficient of the material to be tested by statistically analyzing the time lag between the strain wave and the stress wave in the engineering stress-time curve and the engineering strain-time curve in step C. In step A, the aspect ratio of the micro / nano column is 2 to 4:1, and the taper of the column is no greater than 3°. The taper is the angle formed by the perpendicular lines of the side surface and the bottom surface of the column. If the aspect ratio is too large, the sample will undergo local over-deformation and buckling; if the aspect ratio is too small, there will be significant friction on the sample end face, resulting in bulging and affecting the test results. If the taper is too large, the internal stress distribution of the micro / nano column sample will be uneven, affecting the accuracy of the results. The size of the micro / nano column is selected according to the size of the micro / nano scale device; for example, the bottom diameter of the micro / nano column is 2-5 μm and the length is 6-15 μm. The micro / nano column is processed by focused ion beam or chemical etching. In step B, the micro / nano column undergoes a uniaxial compression test in an in-situ micro / nano mechanical testing system using nanoindentation or electron microscopy, and a flat-head indenter is used for the uniaxial compression test. The cross-sectional diameter of the flat-head indenter is 8-15 μm. The strain rate used in the uniaxial compression test is 0. The maximum strain is set to 5-20% (0.001-0.005s-1). Based on the stress-strain curve from step B, the yield strength, rheological stress, and tensile strength of the material under test are obtained. Then, the stress at the elastic deformation stage is selected for the experiment in step C. In step C, the load ratio used in the periodic uniaxial compression experiment with constant stress amplitude on the micro / nano column is between 0.02 and 0.2, the load frequency is between 5 and 20 Hz, the loading time is between 10 and 100 s, and the total number of cycles is between 50 and 2000. In step D, the time the strain wave lags behind the stress wave is the average strain lag time over multiple cyclic load cycles. For example, values ​​can be taken every 3 cycles, every 5 cycles, or every 10 cycles.

[0005] The above technical solution uses a uniaxial compression experiment of micro-nano cylinders to test the damping coefficient. Since it is not suitable to process the composite diaphragm of headphones into micro-nano cylinders, the above technical solution is not suitable for testing the damping performance of the composite diaphragm of headphones. Summary of the Invention

[0006] This invention provides a method for testing the damping performance of composite diaphragms in acoustic headphones that is convenient to test, has a short testing time, and provides more accurate evaluation of damping performance.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] A method for testing the damping performance of a composite diaphragm sheet for headphones includes the following steps:

[0009] Step S1: Cutting the sample: Cut the composite diaphragm sheet of the earphone into sample pieces of a certain length and width;

[0010] Step S2, Clamping the sample: Fold the sample along its length so that both ends of the sample are completely overlapped, and then clamp the overlapping ends of the sample between the two steel sheets.

[0011] Step S3, Install the sample: Place the steel sheet holding the sample onto the clamp of the universal tensile testing machine, and use the clamp to fix the steel sheet holding the sample.

[0012] Step S4, Compression Test: Start the tensile testing machine and begin the compression test. Record the work done during the compression process (G1) and the work done during the rebound process (G2). Use the difference between G1 and G2 to quantify the damping performance of the headphone composite diaphragm.

[0013] Preferably, in step S1, the sample has a length of 60 mm and a width of 30 mm.

[0014] Preferably, in step S2, the thickness of the steel sheet is 2-3 mm, and the edges need to be chamfered.

[0015] Preferably, in step S2, the sample is clamped between two steel plates with its two ends overlapping along the length direction, with a clamping distance of 5-15mm, preferably 10mm.

[0016] Preferably, in step S2, after the two overlapping ends of the sample are clamped between the two steel sheets, the stacked sample has a structure that is narrow at both ends and wide in the middle.

[0017] Preferably, in step S4, during the pressing and rebounding processes, the software provided with the tensioning machine generates a pressing displacement-pressing tension curve and a rebound displacement-rebound tension curve.

[0018] Preferably, in step S4, the pressing distance and pressing speed of the tensile testing machine are set before pressing.

[0019] Preferably, in step S2, the chamfer of the edge of the steel sheet is R1.0mm.

[0020] Preferably, in step S1, the headphone composite diaphragm is cut using a test strip sampler to obtain several strips.

[0021] The beneficial effects of this invention are as follows:

[0022] The damping performance testing method of the present invention evaluates and quantifies the damping performance of the headphone composite diaphragm by power loss. It not only has the advantages of convenient testing and short testing time, but also provides a more accurate evaluation of the damping performance of the headphone composite diaphragm.

[0023] Another feature of this invention is its versatility; regardless of whether the composite diaphragm has a three-layer or five-layer structure, it can be directly subjected to damping tests.

[0024] This invention can also set different test speeds, and can also design different sample widths and lengths for testing based on the stiffness of the diaphragm itself. Attached Figure Description

[0025] The present invention will be further described with reference to the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the present invention. For those skilled in the art, other drawings can be obtained based on the following drawings without creative effort:

[0026] Figure 1 This is a flowchart of the testing process for the present invention. Detailed Implementation

[0027] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0028] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper surface," "lower surface," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "forward," "reverse," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0029] like Figure 1 As shown, a method for testing the damping performance of a composite diaphragm sheet for headphones includes the following steps:

[0030] Step S1: Cutting the sample: Take a piece of headphone composite diaphragm material with a length of about 1 (or 1.5m or other lengths) and a normal width (e.g., 500cm). Use a peel force test strip sampler (e.g., steel plate) to cut the headphone composite diaphragm material to obtain several test strips of standard size 60mm*30mm. The cut sample can be used as the test sample.

[0031] Step S2: Clamping the Sample: Fold the sample along its length so that both ends completely overlap. Then clamp the overlapping ends of the sample between two steel plates. The steel plates are 2-3mm thick, and their edges need to be chamfered with a radius of 1.0mm. The sample is clamped between the two steel plates with a clamping distance of 5-15mm, preferably 10mm. After clamping the overlapping ends of the sample between the two steel plates, the folded sample will have a petal-shaped structure that is narrow at both ends and wide in the middle. After clamping the steel plates, the outer layer of the steel plates is tightly wrapped with tape to prevent the ends of the sample from coming loose. The two ends of the sample must completely overlap; otherwise, the resulting petal-shaped test strip will be distorted, affecting the test results.

[0032] Step S3, Install the sample: Place the steel sheet holding the sample onto the clamp of the universal tensile testing machine, and use the clamp to fix the steel sheet holding the sample; specifically, put the other end of the two steel sheets into the lower clamp of the tensile testing machine and clamp them, making sure to clamp them in the center so that the stress point of the test sample is always in the center position during the pressing process of the tensile testing machine.

[0033] Step S4, Compression Test: Before compression, set the compression distance and speed of the tensile testing machine, start the machine, and begin the compression test. During the compression and rebound processes, the machine's software generates compression displacement-compression tension curves and rebound displacement-rebound tension curves. Record the work done during the compression process (G1) and the work done during the rebound process (G2). Use the difference between G1 and G2 to quantify the damping performance of the headphone composite diaphragm. Evaluating and quantifying the damping performance of the headphone composite diaphragm through work loss is not only convenient and quick, but also provides a more accurate assessment of its damping performance.

[0034] Another feature of this invention is its versatility; regardless of whether the composite diaphragm has a three-layer or five-layer structure, it can be directly subjected to damping tests.

[0035] Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described herein, as well as the features of those embodiments or examples, without contradiction. Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for testing the damping performance of a composite diaphragm sheet for headphones, characterized in that... This includes the following steps: Step S1: Cutting the sample: Cut the composite diaphragm sheet of the earphone into sample pieces of a certain length and width; Step S2, Clamping the sample: Fold the sample along its length so that the two ends of the sample are completely overlapped. Then clamp the overlapping ends of the sample between two steel sheets along its length, with a clamping distance of 5-15mm. After clamping the overlapping ends of the sample between two steel sheets with a thickness of 2-3mm, the stacked sample will have a petal-shaped structure that is narrow at both ends and wide in the middle. Step S3, Install the sample: Place the steel sheet holding the sample onto the clamp of the universal tensile testing machine, use the clamp to fix the steel sheet holding the sample, and clamp it in the center so that the stress point of the test sample is always in the center position during the pressing process of the tensile testing machine. Step S4, Compression Test: Start the tensile testing machine and begin the compression test. Record the work done during the compression process (G1) and the work done during the rebound process (G2). Use the difference between G1 and G2 to quantify the damping performance of the headphone composite diaphragm.

2. The method for testing the damping performance of the headphone composite diaphragm sheet according to claim 1, characterized in that: In step S1, the sample is 60mm long and 30mm wide.

3. The method for testing the damping performance of the headphone composite diaphragm sheet according to claim 1, characterized in that: In step S2, the edges of the steel sheet are chamfered.

4. The method for testing the damping performance of the headphone composite diaphragm sheet according to claim 1, characterized in that: In step S2, the sample is clamped between two steel plates with its two ends aligned along its length, with a clamping distance of 10mm.

5. The method for testing the damping performance of the headphone composite diaphragm sheet according to claim 1, characterized in that: In step S4, during the pressing and rebounding processes, the software built into the tension testing machine generates a pressing displacement-pressing tension curve and a rebound displacement-rebound tension curve.

6. The method for testing the damping performance of the headphone composite diaphragm sheet according to claim 1, characterized in that: In step S4, before pressing down, the pressing distance and pressing speed of the tensile testing machine are set.

7. The method for testing the damping performance of the composite diaphragm sheet for headphones according to claim 3, characterized in that: In step S2, the edge chamfer of the steel sheet is R1.0mm.

8. The method for testing the damping performance of the headphone composite diaphragm sheet according to claim 1, characterized in that: In step S1, the headphone composite diaphragm is cut using a test strip sampler to obtain several strips.

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