An automobile sheath sound insulation performance testing device and testing method

Abstract

An automobile sheath sound insulation performance testing device and testing method belong to the technical field of automobile sheaths, and solve the problems that the existing automobile sheath sound insulation testing device is inconvenient because the test sample can only be placed on the test window between two test chambers, and the disassembly and assembly of the test window are also time-consuming and laborious. The device includes: a sheath test assembly, a test structure, a round hole plug and a comparison sheet metal; the round hole plug includes 3 pieces of lead sheets and 3 diffusers; the test structure includes a test tube; 3 round holes on the test tube are blocked with 3 pieces of lead sheets or 3 diffusers; a comparison sheet metal or a sheath test assembly is installed at the right end of the test tube.

Description

Technical Field

[0001] The present invention relates to the technical field of automotive sheaths, and particularly relates to a device and a method for testing the sound insulation performance of an automotive sheath. Background Art

[0002] In the sound insulation test of automotive sheaths, mainly a sheet metal with a sheath is embedded in the test window of a reverberation chamber and an anechoic chamber, and the sealing is done well. A sound source is turned on in the reverberation chamber, and the sound pressure level a in the reverberation chamber is measured. Then, the sound intensity level b near the sheath in the anechoic chamber is measured with a sound intensity scanner. Finally, the sound insulation performance STL of the sheath = a - b - 6.

[0003] In the existing test methods, as Figure 1 shown, to ensure the noise uniformity in the reverberation chamber and be close to an ideal diffuse sound field, the reverberation chamber is usually more than 200m 3 above, and the anechoic chamber is also very large. That is, the test sample can only be placed on the test window between the two test chambers, which is not convenient, and the disassembly and assembly of the test window are also time-consuming and laborious.

[0004] Therefore, the defect of the existing automotive sheath sound insulation test device is that the test sample can only be placed on the test window between the two test chambers, which is not convenient, and the disassembly and assembly of the test window are also time-consuming and laborious.

[0005] In the prior art, there has been no improvement scheme for the problem that the automotive sheath sound insulation test device is not convenient because the test sample can only be placed on the test window between the two test chambers, and the disassembly and assembly of the test window are also time-consuming and laborious. For example: Patent document CN113931743A discloses "a perforated sound insulation cover". Through modal, impact calculations and tests, it can be known that the strength of the perforated sound insulation cover meets the use requirements. The technical solution described in this patent document can solve the problem that the strength of the perforated sound insulation cover meets the use requirements. Patent document CN207879205U discloses "a detachable acoustic test window system". By providing a modular detachable movable window frame and a movable test window sash, it can be quickly disassembled and assembled, and test pieces of different sizes can be interchanged at any time, which can greatly shorten the time for replacing test pieces, effectively save test costs, and there is no need to destructively disassemble the original wall and window. The technical solution described in this patent document can greatly shorten the time for replacing test pieces, effectively save test costs, and there is no need to destructively disassemble the original wall and window.

[0006] In summary, although the existing test device can achieve the purpose of acoustic testing, since the test sample can only be placed on the test window between the two test chambers, it will cause inconvenience, and the disassembly and assembly of the test window are also time-consuming and laborious. Summary of the Invention

[0007] The present invention solves the problems of the existing automobile jacket sound insulation testing device in that the test sample can only be placed on the test window between two test chambers, which is inconvenient and the disassembly and assembly of the test window is time-consuming and labor-intensive.

[0008] The present invention provides a vehicle jacket sound insulation performance testing device, comprising: a jacket testing assembly, a testing structure, a circular hole blocking block, and a comparison sheet metal 2;

[0009] The circular hole block includes three pieces of lead sheets 13 and three diffusers 12; the test structure includes a test tube 4;

[0010] The three circular holes on the test tube 4 are blocked with three pieces of lead sheets 13 or three diffusers 12;

[0011] The right end of the test tube 4 is installed with a comparison sheet metal 2 or a sheath test assembly.

[0012] Furthermore, in an embodiment of the present invention, the sheath test assembly includes a fixture sheet metal 1 and a sheath 3;

[0013] The sheath 3 is mounted on the fixture sheet metal 1 .

[0014] Furthermore, in an embodiment of the present invention, the test structure includes a piston 7, a speaker 8, an amplifier 5 and a connecting harness 1;

[0015] The piston 7 is located at the left end of the test tube 4 , and the top of the piston 7 is an arc surface. The top arc surface of the piston 7 is connected to a speaker 8 , and the speaker 8 is connected to the amplifier 5 via a connecting harness 11 .

[0016] Furthermore, in an embodiment of the present invention, the test structure further includes a double-sided tape 9;

[0017] The comparison sheet metal 2 or the sheath test assembly is connected to the right end of the test tube 4 via double-sided tape 9 .

[0018] Furthermore, in an embodiment of the present invention, the test structure further includes a data acquisition device 6 and a microphone 10;

[0019] A microphone 10 is arranged outside the right end of the test tube 4 . The microphone 10 is connected to the data acquisition device 6 via a connecting harness 11 . At this time, the microphone 10 and the test tube 4 are coaxial.

[0020] Furthermore, in an embodiment of the present invention, the microphone 10 is 20 cm away from the right end of the test tube 4 .

[0021] Furthermore, in an embodiment of the present invention, the diameter of the three circular holes on the test tube 4 is 5 cm, and the distances from the centers of the three circular holes to the right end of the test tube 4 are 11 cm, 17 cm, and 29 cm, respectively.

[0022] Furthermore, in the embodiment of the present invention, the thickness of the lead sheet 13 is 2.5 mm, the diffuser 12 is conical, and the height is 11 cm.

[0023] A method for testing the sound insulation performance of an automotive sheath according to the present invention is realized by using a device for testing the sound insulation performance of an automotive sheath described in the above method, and includes the following steps:

[0024] Step S1: Install the comparison sheet metal 2 at the right end of the test tube 4. Seal the three round holes on the test tube 4 with three lead sheets 13. Enable the power amplifier 5 to emit white noise from 100 Hz to 20,000 Hz. The data acquisition device 6 collects for 30 seconds, and the microphone 10 obtains the one-third octave band B from 100 Hz to 20,000 Hz;

[0025] Step S2: Replace the comparison sheet metal 2 with the sheath test assembly. Measure the sound pressure level R1 according to Step S1, calculate the insertion loss IL1 of the sheath test assembly, then replace one lead sheet 13 with a diffuser 12 and measure the insertion loss IL2 in the same way. Finally, replace the lead sheets 13 at different positions and in different quantities with diffusers 12, and a total of 2 3 insertion losses are measured, and their average value is taken to obtain the insertion loss Ila;

[0026] Step S3: Move the piston 7 30 cm to the left, obtain the insertion loss ILb according to Step S2, and then move the piston 7 20 cm to the left and obtain the insertion loss ILc according to Step S2;

[0027] Step S4: Calculate the average value of ILa, ILb, and ILc to obtain the insertion loss IL of the test tube 4.

[0028] Furthermore, in the embodiment of the present invention, in Step S2, the formula for calculating the insertion loss IL1 of the sheath test assembly is:

[0029] IL1 = B - R1, where B is the frequency band and R1 is the sound pressure level.

[0030] The present invention solves the problem that the existing device for testing the sound insulation of an automotive sheath can only be placed on the test window between two test rooms, which is not convenient, and the disassembly and assembly of the test window are also time-consuming and laborious. The specific beneficial effects include:

[0031] 1. The present invention proposes a device for testing the sound insulation performance of an automotive sheath. The device uses a small box, which is small and convenient for testing, and does not need to be placed on the test window between two test rooms. At the same time, it also solves the problem that the disassembly and assembly of the test window are time-consuming and laborious.

[0032] 2. The present invention provides a device for testing the sound insulation performance of an automotive sheath. The prior art sheath sound insulation testing device requires a sound intensity scanner to collect signals, while this device only uses one microphone, with simple instruments and low costs.

[0033] 3. The present invention provides a device for testing the sound insulation performance of an automotive sheath. Although the space inside the test tube is small, resulting in an uneven sound field, this situation can be improved by adding an arc-shaped piston. Moreover, through the arrangement and combination of multiple diffusers and different piston positions, a statistical average can be obtained after multiple tests, which better represents the sound insulation performance under a comprehensive sound field.

[0034] 4. The present invention provides a method for testing the sound insulation performance of an automotive sheath. In practical applications, the space near the automotive sheath is limited and not a uniformly diffused sound field, and the sound fields vary due to different sheath environments. Therefore, the test results of this testing method are closer to the actual sound insulation performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of the embodiments in conjunction with the drawings, where:

[0036] Figure 1 It is a diagram showing the sound insulation performance of the sheath measured in the reverberation chamber and anechoic chamber as described in the background art.

[0037] Figure 2 It is a drawing of the fixture sheet metal as described in the specific embodiment; (1) is the fixture sheet metal.

[0038] Figure 3 It is a comparative sheet metal drawing as described in the specific embodiment; (2) is the comparative sheet metal.

[0039] Figure 4 It is a drawing of the sheath test assembly as described in the specific embodiment; (3) is the sheath.

[0040] Figure 5 It is a drawing of the cylindrical test tube as described in the specific embodiment; (4) is the test tube; (5) is the power amplifier; (6) is the data acquisition device; (7) is the piston; (8) is the speaker; (9) is the double-sided tape; (10) is the microphone; (11) is the connection wire harness.

[0041] Figure 6 It is a drawing of the round hole plug as described in the specific embodiment; (12) is the diffuser; (13) is the lead sheet.

[0042] Figure 7 It is a drawing of the comparative sheet metal installed at the right end of the test tube as described in the specific embodiment.

[0043] Figure 8 It is a drawing of the sheath test assembly installed at the right end of the test tube as described in the specific embodiment.

[0044] Figure 9 The test chart for changing the piston position described in the specific implementation mode. Specific implementation mode

[0045] The following will clearly and completely describe various implementation modes of the present invention in conjunction with the accompanying drawings. The embodiments described by referring to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as a limitation to the present invention.

[0046] A device for testing the sound insulation performance of an automotive sheath according to this implementation mode, the device includes: a sheath test assembly, a test structure, a round hole plug and a comparison sheet metal 2;

[0047] The round hole plug includes 3 pieces of lead sheet 13 and 3 diffusers 12; the test structure includes a test tube (4);

[0048] Three round holes on the test tube 4 are blocked with 3 pieces of lead sheet 13 or 3 diffusers 12;

[0049] A comparison sheet metal 2 or a sheath test assembly is installed at the right end of the test tube 4.

[0050] In this implementation mode, the sheath test assembly includes a clamp sheet metal 1 and a sheath 3;

[0051] The sheath 3 is installed on the clamp sheet metal 1.

[0052] In this implementation mode, the test structure includes a piston 7, a speaker 8, a power amplifier 5 and a connection wire harness 11;

[0053] The piston 7 is located at the left end of the test tube 4, and the top of the piston 7 is an arc surface. A speaker 8 is connected to the top arc surface of the piston 7, and the speaker 8 is connected to the power amplifier 5 through the connection wire harness 11.

[0054] In this implementation mode, the test structure further includes double-sided tape 9;

[0055] The comparison sheet metal 2 or the sheath test assembly is connected to the right end of the test tube 4 through the double-sided tape 9.

[0056] In this implementation mode, the test structure further includes a data acquisition device 6 and a microphone 10;

[0057] The microphone 10 is arranged outside the right end of the test tube 4. The microphone 10 is connected to the data acquisition device 6 through the connection wire harness 11. At this time, the microphone 10 is coaxial with the test tube 4.

[0058] In this implementation mode, the microphone 10 is 20 cm away from the right end of the test tube 4.

[0059] In this embodiment, the diameters of the three round holes on the test tube 4 are 5 cm, and the distances from the centers of the diameters of the three round holes to the right end of the test tube 4 are 11 cm, 17 cm, and 29 cm respectively.

[0060] In this embodiment, the thickness of the lead sheet 13 is 2.5 mm, and the diffuser 12 is conical with a height of 11 cm.

[0061] A method for testing the sound insulation performance of an automobile sheath according to this embodiment is realized by using the device for testing the sound insulation performance of an automobile sheath described in the above embodiment, and includes the following steps:

[0062] Step S1: Install the comparison sheet metal 2 at the right end of the test tube 4, block the three round holes on the test tube 4 with three lead sheets 13, enable the power amplifier 5 to emit white noise from 100 Hz to 20,000 Hz, the data acquisition device 6 collects for 30 seconds, and the microphone 10 obtains the one-third octave band B from 100 Hz to 20,000 Hz;

[0063] Step S2: Replace the comparison sheet metal 2 with the sheath test assembly, measure the sound pressure level R1 according to Step S1, calculate the insertion loss IL1 of the sheath test assembly, then replace one lead sheet 13 with a diffuser 12 and measure the insertion loss IL2 in the same way, and finally replace the lead sheets 13 at different positions and in different quantities with diffusers 12, and a total of 2 3 insertion losses are measured, and their average value is taken to obtain the insertion loss Ila;

[0064] Step S3: Move the piston 7 30 cm to the left, obtain the insertion loss ILb according to Step S2, and then move the piston 7 20 cm to the left and obtain the insertion loss ILc according to Step S2;

[0065] Step S4: Calculate the average value of ILa, ILb, and ILc to obtain the insertion loss IL of the test tube 4.

[0066] In this embodiment, the formula for calculating the insertion loss IL1 of the sheath test assembly is:

[0067] IL1 = B - R1, where B is the frequency band and R1 is the sound pressure level.

[0068] The structure and working principle of the present invention will be described in detail below with reference to the accompanying drawings:

[0069] Fabricate the fixture sheet metal 1, as Figure 2 shown. The fixture sheet metal 1 is circular with a diameter of 20 cm, and its thickness is the same as that of the corresponding sheet metal of the sheath on the vehicle. An opening is made in the middle of the fixture sheet metal 1, and the size and shape of the opening are the same as those of the opening for installing the sheath on the vehicle.

[0070] Fabricate the comparison sheet metal 2, as Figure 3As shown, it has the same size, shape and thickness as the fixture sheet metal 1, but is only for comparison purposes.

[0071] Fabricate the sheath test assembly as Figure 4 shown. Install the sheath 3 containing the wrapped components (such as electrical wiring harness, water pipe, etc.) onto the fixture sheet metal 1 to form the sheath test assembly.

[0072] Fabricate the test tube 4 as Figure 5 shown. Fabricate a cylindrical test tube 4 with a diameter of 30 cm and a wall thickness of 3 mm. There are 3 round holes on it with a hole diameter of 5 cm. The center distances of the hole diameters from the right end face are 11 cm, 17 cm, and 29 cm respectively. The left end of the test tube 4 is a piston, and the top of the piston is an arc surface to facilitate the diffusion of sound. There is a speaker on the arc surface, which is connected to the power amplifier 5. Double-sided tape 9 is pasted on the right end of the test tube to facilitate close fitting with the fixture sheet metal 1 to prevent sound leakage. A field microphone 8 is arranged outside the right end of the test tube 4. The microphone 10 is connected to the data acquisition device 6, which is coaxial with the test tube 4 and is 20 cm away from the right end of the test tube 4.

[0073] Fabricate the round hole plugs as Figure 6 shown. Fabricate 3 plastic diffuser 12 plugs and 3 pieces of lead sheets 13. The diffuser 12 is conical with a height of 11 cm and can fit tightly with the round holes of the test tube 4. The lead sheet 13 has a thickness of 2.5 mm and an area larger than the opening of the test tube 4, which can provide complete sealing.

[0074] Conduct the comparison sheet metal test as Figure 7 shown. Install the comparison sheet metal 2 onto the right end of the test tube 4. All the round holes of the test tube 4 are blocked with lead sheets 13. Start the power amplifier 5 to emit white noise from 100 Hz to 20,000 Hz. The data acquisition device 6 collects data for 30 seconds to obtain the one-third octave band spectrum B of the microphone from 100 Hz to 20,000 Hz.

[0075] Conduct the sheath sound insulation test as Figure 8 shown. Replace the comparison sheet metal 2 with the sheath test assembly. Similarly, measure R1; subtract R1 from B to obtain the insertion loss IL1 of the sheath 3 in this state; then replace one piece of lead sheet 13 with a diffuser 12 and measure IL2. Finally, by replacing different numbers of lead sheets 13 with diffusers 12 at different positions, a total of 2 3 results are measured, and their average value is taken to obtain the insertion loss ILa.

[0076] Conduct the test by changing the position of the piston 7 as Figure 9 shown. Move the piston 7 30 cm to the left. According to the above method, obtain the insertion loss ILb; then move the piston 7 20 cm to the left. According to the above method, obtain the insertion loss ILc.

[0077] Calculate the average value of the insertion losses at each position. Take the average of ILa, ILb, and ILc to obtain the insertion loss IL of the test tube.

Claims

1. A method for testing the sound insulation performance of an automotive sheath, which is realized by using a testing device for the sound insulation performance of an automotive sheath, characterized in that, The device includes: a sheath test assembly, a test structure, a round hole plug, and a comparison sheet metal (2); The round hole plug includes 3 pieces of lead sheet (13) and 3 diffusers (12); the test structure includes a test tube (4); Three round holes on the test tube (4) are blocked by 3 pieces of lead sheet (13) or 3 diffusers (12); A comparison sheet metal (2) or a sheath test assembly is installed at the right end of the test tube (4); The test structure includes a piston (7), a speaker (8), a power amplifier (5), and a connecting wire harness (11); The piston (7) is located at the left end of the test tube (4), and the top of the piston (7) is an arc surface. The speaker (8) is connected to the top arc surface of the piston (7), and the speaker (8) is connected to the power amplifier (5) through the connecting wire harness (11); The test structure further includes a data acquisition device (6) and a microphone (10); The microphone (10) is arranged outside the right end of the test tube (4). The microphone (10) is connected to the data acquisition device (6) through the connecting wire harness (11). At this time, the microphone (10) and the test tube (4) are coaxial; It includes the following steps: Step S1, install the comparison sheet metal (2) at the right end of the test tube (4). Three round holes on the test tube (4) are blocked by 3 pieces of lead sheet (13). Enable the power amplifier (5) to emit white noise from 100 Hz to 20000 Hz. The data acquisition device (6) acquires for 30 seconds, and the microphone (10) obtains the one-third octave B from 100 Hz to 20000 Hz; Step S2: Replace the comparison sheet metal (2) with the sheath test assembly. Measure the sound pressure level R1 according to Step S1, calculate the insertion loss IL1 of the sheath test assembly. Then replace a piece of lead sheet (13) with a diffuser (12) and measure the insertion loss IL2 in the same way. Finally, replace different numbers of lead sheets (13) with diffusers (12) at different positions, and a total of 2 3 insertion losses are measured. Average them to obtain the insertion loss Ila; Step S3, move the piston (7) 30 cm to the left, obtain the insertion loss ILb according to Step S2, then move the piston (7) 20 cm to the left, and obtain the insertion loss ILc according to Step S2; Step S4, calculate the average value of ILa, ILb, and ILc to obtain the insertion loss IL of the test tube (4).

2. The acoustic insulation performance test method of an automotive sheath according to claim 1, wherein The sheath test assembly includes a fixture sheet metal (1) and a sheath (3); The sheath (3) is installed on the fixture sheet metal (1).

3. A method for testing the sound insulation performance of an automotive sheath according to claim 1, characterized in that The test structure further includes double-sided tape (9); The comparison sheet metal (2) or the sheath test assembly is connected to the right end of the test tube (4) through the double-sided tape (9).

4. A method for testing the sound insulation performance of an automobile sheath according to claim 1, characterized in that, The microphone (10) is 20 cm away from the right end of the test tube (4).

5. A method for testing the sound insulation performance of an automotive sheath according to claim 1, characterized in that, The diameters of the 3 round holes on the test tube (4) are 5 cm, and the center distances of the 3 round hole diameters from the right end of the test tube (4) are 11 cm, 17 cm, and 29 cm respectively.

6. The method for testing the sound insulation performance of an automotive sheath according to claim 1, wherein The thickness of the lead sheet (13) is 2.5 mm, and the diffuser (12) is conical with a height of 11 cm.

7. A method for testing the sound insulation performance of an automobile sheath according to claim 1, characterized in that, In the said Step S2, the formula for calculating the insertion loss IL1 of the sheath test assembly is: IL1 = B - R1, where B is the frequency band and R1 is the sound pressure level.

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