Noise test experimental device

Abstract

The present invention provides a noise testing experimental device, including an orifice plate test bench for placing a test piece, a silencer base for reducing the noise of the test piece, a lifting mechanism arranged on the orifice plate test bench, and a push rod connected to the lifting mechanism, wherein the silencer base has a silencer cavity arranged opposite to the push rod, and the push rod moves with the lifting mechanism to change the length of the push rod extending into the silencer cavity and the cavity height of the silencer cavity. In the noise testing experimental device provided by the present invention, when the push rod moves with the lifting mechanism, the depth of the push rod inserted into the silencer cavity can be changed, and accordingly, the cavity height of the silencer cavity changes accordingly. By using the noise testing experimental device, there is no need to re-sample after each test, and the cavity height of the silencer cavity can be quickly adjusted, thereby shortening the design cycle of the silencer, reducing the design workload, and reducing the design cost.

Description

Technical Field

[0001] The invention belongs to the technical field of noise reduction, and more specifically, relates to a noise testing experimental device. Background Art

[0002] In daily industrial applications, high-speed vacuum suction motors generally have the problem of high noise, and the noise will be even louder at higher speeds. Therefore, the noise problem has always been one of the important issues that need to be improved and solved for this type of motor; the noise components of vacuum suction motors are mainly divided into pneumatic noise, mechanical noise and electromagnetic noise; and the pneumatic noise generated by the high-speed rotation of the vacuum suction motor impeller is much louder than its electromagnetic noise and mechanical noise, and pneumatic noise is the main noise of this type of motor.

[0003] The pneumatic noise of the vacuum suction motor can be divided into: 1. Due to the rotation of the impeller, the impeller blades will generate pneumatic noise (i.e. BPF noise) through the diffuser flow channel; 2. Broadband noise formed by the normal flow of air in the flow channel. Among them, BPF noise shows a sharp peak feature in the noise spectrum of the motor. Its characteristic frequency is the product of the rotation frequency of the motor and the number of impeller blades. In the noise spectrum, it is distributed with 1 times BPF noise frequency, 2 times BPF noise frequency, 3 times BPF noise frequency and other frequency peak characteristics. BPF noise contributes the most to the overall pneumatic noise of the vacuum suction motor and is the most important noise of this type of motor.

[0004] For the noise problem of vacuum motors with a fixed design, the method of active noise reduction by changing the flow channel shape and impeller design is generally difficult to operate due to the fixed design. Therefore, the most commonly used method for this type of noise problem is passive noise reduction, such as using sound-absorbing materials and sound-absorbing structures, sound-insulating materials and sound-insulating structures for sound absorption and sound insulation, or using silencers to reduce noise in fixed frequency bands.

[0005] Due to the high degree of integration of vacuum motors, there is not much suitable extra space on the actual motor to eliminate noise by applying sound-absorbing or noise-reducing materials and structures. The use of the quarter-wavelength tube silencer principle to reduce the noise amplitude of the BPF at a fixed frequency is currently a widely used noise control method.

[0006] At present, the design process of quarter-wavelength tube silencer is mainly carried out through theoretical formula calculation and finite element simulation calculation. Then, actual testing is carried out through actual proofing to verify the effect of the design scheme. If the error between the design result and the actual result is large, the formula correction factor is modified according to the actual test result or the simulation model is re-calibrated and calculated, and then proofing, testing and comparison are carried out until the design requirements are finally met.

[0007] In addition, a quarter-wavelength tube muffler is designed for BPF noise of different frequencies through theoretical calculations. First, the frequency of the target BPF noise before the muffler is installed needs to be measured. After the muffler is designed and manufactured, it is installed on the actual product for verification. Since the installation of the muffler will affect the actual performance of the vacuum motor, the target BPF noise frequency after the muffler is installed will be different from the target BPF noise frequency before the muffler is installed. This difference will lead to unsatisfactory actual test results of the quarter-wavelength tube muffler.

[0008] Since this design method cannot quickly adapt and verify the design solution during the intermediate process, this method not only has a complicated process, a long design cycle, and a large workload, but also has a high cost and is not conducive to rapid product improvement and iteration. Summary of the invention

[0009] The purpose of the present invention is to provide a noise testing experimental device to solve the technical problems existing in the prior art such as long muffler design cycle, large workload and high cost.

[0010] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: to provide a noise testing experimental device, including a perforated plate method test bench for placing a test piece under test, a silencer base for reducing the noise of the test piece under test, a lifting mechanism arranged on the perforated plate method test bench, and a push rod connected to the lifting mechanism, the silencer base having a silencer cavity arranged opposite to the push rod, and the push rod moves with the lifting mechanism to change the length of the push rod extending into the silencer cavity and the cavity height of the silencer cavity.

[0011] In one embodiment, the number of the push rods and the number of the muffler cavities are both plural, and the number of the push rods is the same as the number of the muffler cavities.

[0012] In one embodiment, the push rods are arranged in a ring shape, the silencer base is ring-shaped, and the silencer cavities are arranged in a ring shape in the silencer base. The measured object is disposed in the silencer base, so that the silencer cavities are arranged in a ring shape on the periphery of the measured object.

[0013] In one embodiment, the moving end of the lifting mechanism is connected to a mounting plate, and the ends of each of the push rods are fixed to the mounting plate; the mounting plate is provided with a plurality of circular hole arrays with different diameters to accommodate various models of test pieces, and each of the push rods is fixed in a circular hole of the same circular hole array.

[0014] In one embodiment, there are multiple lifting mechanisms, and the moving end of each lifting mechanism is connected to at least one of the push rods.

[0015] In one embodiment, the lifting mechanism is a screw mechanism, a cylinder mechanism or a linear motor mechanism.

[0016] In one embodiment, the screw mechanism includes a lifting motor, a screw driven to rotate by the lifting motor, and a screw nut connected to the screw, and the screw nut is the moving end of the screw mechanism.

[0017] In one embodiment, the screw mechanism further includes a lifting plate and a guide rod, wherein the lifting plate is fixed to the screw nut, and the guide rod is arranged through the lifting plate, and the length directions of the guide rod and the screw are parallel.

[0018] In one embodiment, an annular holder is fixed on the orifice plate method test bench, the silencing matrix is ​​arranged in the annular holder, and the test piece is arranged in the silencing matrix.

[0019] In one embodiment, the device under test is a motor, and the silencer matrix is ​​disposed on the outer periphery of the stator of the motor.

[0020] The noise test experimental device provided by the present invention has the beneficial effect that: compared with the prior art, the noise test experimental device of the present invention includes a perforated plate method test bench for placing the test piece, a muffler base, a lifting mechanism and a push rod. The push rod is connected to the lifting mechanism and can move with the lifting mechanism. The muffler base has a muffler cavity arranged opposite to the push rod. When the push rod moves with the lifting mechanism, the depth of the push rod inserted into the muffler cavity can be changed, and accordingly, the cavity height of the muffler cavity changes accordingly. The muffler principle of the muffler cavity is equivalent to the muffler principle of a quarter-wavelength tube. When the height of the muffler cavity changes, the noise reduction frequency band corresponding to the muffler base changes. In this way, the cavity height of the muffler cavity can be changed by moving the push rod, and then the calculation is rechecked according to the actual noise reduction test results, and then the length of the push rod extending into the muffler cavity is re-adjusted according to the calculation results until the design requirements of noise reduction are met. Using the noise test experimental device, there is no need to re-sample after each test, and the cavity height of the muffler cavity can be quickly adjusted, thereby shortening the design cycle of the muffler, reducing the design workload, and reducing the design cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0022] Figure 1 A three-dimensional structural diagram of a noise testing experimental device provided in an embodiment of the present invention;

[0023] Figure 2 A three-dimensional structural diagram of a test piece and a noise-absorbing substrate provided in an embodiment of the present invention;

[0024] Figure 3 A cross-sectional view of a test piece and a muffler substrate provided in an embodiment of the present invention;

[0025] Figure 4 This is the structural principle diagram of the quarter-wavelength tube noise reduction;

[0026] Figure 5 A three-dimensional structural diagram of a mounting plate provided in an embodiment of the present invention;

[0027] Figure 6 A rear view of the lead screw mechanism provided by an embodiment of the present invention;

[0028] Figure 7 A cross-sectional view of a lead screw mechanism provided in an embodiment of the present invention.

[0029] Among them, the reference numerals in the figure are:

[0030] 010-test piece; 020-main pipe; 030-quarter wavelength pipe; 1-orifice plate method test bench; 2-annular holder; 3-muffler base; 30-muffler cavity; 4-lifting mechanism; 41-lifting motor; 42-motor mounting seat; 43-lifting plate; 44-guide rod; 45-screw; 46-screw slider; 47-bearing; 5-thrust rod; 6-mounting plate; 61-circular hole array. DETAILED DESCRIPTION

[0031] 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 in conjunction with 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.

[0032] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can 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 can be directly connected to the other element or indirectly connected to the other element.

[0033] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0034] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0035] The noise test experimental device provided by the embodiment of the present invention is now described. The noise test experimental device can be applied to a vacuum suction motor that uses an orifice plate test device according to the ASTM F431-03 standard to perform performance tests.

[0036] See also Figure 1 In one embodiment, the noise test experimental device includes an orifice plate test bench 1, a muffler base 3, a lifting mechanism 4 and a push rod 5. The orifice plate test bench 1 includes a pressure gauge, an orifice plate assembly and other structures, and the test piece 010 is installed on the orifice plate assembly. The specific structure of the orifice plate test bench 1 is not described here, please refer to the link https: / / www.docin.com / p-1458340691.html Figure 4 .2. The test piece 010 is placed on the orifice plate test bench 1, and the silencer matrix 3 is also arranged on the orifice plate test bench 1, which is used to reduce the airflow noise generated by the test piece 010. The lifting mechanism 4 is arranged on the orifice plate test bench 1, and the push rod 5 is connected to the moving end of the lifting mechanism 4, so that the push rod 5 can move with the moving end of the lifting mechanism 4. The length direction of the push rod 5 is parallel to the moving direction of the lifting mechanism 4. Optionally, the moving direction of the moving end of the lifting mechanism 4 is the up and down direction, the push rod 5 is correspondingly arranged vertically, and the moving direction of the push rod 5 is also the vertical direction; the moving direction of the moving end of the lifting mechanism 4 can also be the horizontal direction, the push rod 5 is correspondingly arranged horizontally, and the moving direction of the push rod 5 is also the horizontal direction. The setting direction and moving direction of the push rod 5 are not limited here, as long as it can be extended into and out of the silencer matrix 3. The muffler base 3 has a muffler cavity 30 arranged opposite to the push rod 5. The push rod 5 can be extended into or moved out of the muffler cavity 30 along with the lifting mechanism 4. The length of the push rod 5 extending into the muffler cavity 30 can be adjusted by the lifting mechanism 4. As the push rod 5 moves, the length of the push rod 5 extending into the muffler cavity 30 gradually changes. Accordingly, the remaining cavity height of the muffler cavity 30 also gradually changes, and the frequency of the muffler cavity 30 that can reduce noise also changes. In the process of design, testing, and verification, the noise reduction frequency can be changed by changing the extension length of the push rod 5. The experimental conditions can be changed at any time, and the height of the muffler cavity 30 suitable for the test piece 010 can be measured more quickly.

[0037] The noise test experimental device in the above embodiment includes a perforated plate method test bench 1 for placing the test piece 010, a noise reduction base 3, a lifting mechanism 4 and a push rod 5. The push rod 5 is connected to the lifting mechanism 4 and can move with the lifting mechanism 4. The noise reduction base 3 has a noise reduction cavity 30 arranged opposite to the push rod 5. When the push rod 5 moves with the lifting mechanism 4, the depth of the push rod 5 inserted into the noise reduction cavity 30 can be changed, and accordingly, the cavity height of the noise reduction cavity 30 changes accordingly. The noise reduction principle of the noise reduction cavity 30 is equivalent to the noise reduction principle of the quarter-wavelength tube 030. When the height of the noise reduction cavity 30 changes, the noise reduction frequency band corresponding to the noise reduction base 3 changes. In this way, the cavity height of the noise reduction cavity 30 can be changed by moving the push rod 5, and then the calculation can be re-checked according to the actual noise reduction test results, and then the length of the push rod 5 extending into the noise reduction cavity 30 can be readjusted according to the calculation results until the design requirements of noise reduction are met. By using the noise testing experimental device, there is no need to re-sample after each test, and the cavity height of the silencer cavity 30 can be quickly adjusted, thereby shortening the design cycle of the silencer, reducing the design workload, and lowering the design cost.

[0038] When the tested object 010 is a motor, the internal structure of the motor is compact. Pipe silencers include resistive silencers, anti-type silencers and mixed silencers. Anti-type silencers usually include Helmholtz silencers and quarter-wavelength silencers. Helmholtz silencers are usually used to eliminate low-frequency noise, and the required silencer cavity volume is large, which is not suitable for silencers with small structure designs. The quarter-wavelength tube 030 silencer is used to eliminate relatively high-frequency noise. The higher the frequency, the smaller the volume of the silencer is relatively, which is suitable for motors. Moreover, the impeller speed of the motor is relatively high, and the frequency of the BPF noise generated during actual operation is also relatively high, so the quarter-wavelength tube 030 is selected for silencer, and the silencer cavity 30 is equivalent to silencer in the form of a quarter-wavelength tube 030. The quarter-wavelength tube 030 silencer only needs to be a branch of the main pipe 020, and its pipe length needs to be one-fourth of the wavelength of the frequency to be silenced.

[0039] See also Figure 4 , Figure 4 The structure principle diagram of the quarter-wavelength tube 030 is shown in FIG. The noise reduction principle of the silencing cavity 30 in the embodiment of the present invention is the same as that of the quarter-wavelength tube 030. Figure 4When the muffler is used, part of the incident wave is reflected back to the main pipe 020 to form a reflected wave, part of the incident wave continues to propagate in the main pipe 020 to form a transmitted wave, and part of the sound wave enters the quarter-wavelength pipe 030. In the quarter-wavelength pipe 030, when the incident sound wave encounters the boundary, part of the wave will be reflected back to the quarter-wavelength pipe 030. At the interface between the main pipe 020 and the quarter-wavelength pipe 030, the reflected sound wave of a specific frequency in the quarter-wavelength pipe 030 is opposite in phase to the incident sound wave of the main pipe 020, and the two sound waves cancel each other to form a node of sound pressure or reduce the amplitude of the incident sound wave, thereby achieving the purpose of muffler. The above-mentioned specific frequency f=c / (4L), where c is the speed of sound wave, f is the muffler frequency, and L is the length of the quarter-wavelength pipe 030. That is, the level of muffler frequency depends only on the length (depth) of the side branch pipe. The design of the quarter-wavelength tube 030 silencer is mainly to study the length of the side branch pipe, that is, it is necessary to test and verify whether the length of the side branch pipe calculated by theoretical calculation or simulation is compatible with the actual frequency. In the traditional experimental method, when adjusting the design scheme, it is necessary to make multiple samples of different lengths according to the theoretical calculation or simulation results and test them separately. In the present invention, one silencer base 3 can test multiple design schemes of different lengths, and can eliminate the difference in influence on the test piece 010 before and after the silencer is installed.

[0040] See also Figure 1 and Figure 2 In one embodiment, the number of the top rods 5 and the number of the silencer cavities 30 are both multiple, and the number of the top rods 5 is the same as the number of the silencer cavities 30. Only when the number of the silencer cavities 30 is multiple can a better noise reduction effect be achieved. It is difficult for a single silencer cavity 30 to simultaneously perform noise reduction on the airflow around the test piece 010. Optionally, the silencer matrix 3 itself is annular, and the test piece 010 is arranged in the area surrounded by the silencer matrix 3. Each silencer cavity 30 is also arranged in a ring shape and is opened in the silencer matrix 3. In this way, each silencer cavity 30 surrounds the outer periphery of the test piece 010, and can perform sufficient noise reduction on the airflow around the test piece 010. Correspondingly, the top rods 5 are also arranged in a ring shape, and the arrangement of the top rods 5 is the same as the arrangement of the silencer cavities 30.

[0041] Among them, see Figure 3 When the tested component 010 is a motor, the motor is arranged in the area surrounded by the silencer base 3, and the rotor of the motor, the stator of the motor and the silencer base 3 are arranged in sequence from the inside to the outside. Figure 3 The direction of the arrow in the middle is the approximate flow direction of the airflow. When the airflow flows to the entrance of the muffler cavity 30, the muffler cavity 30 will reduce the noise of a specific frequency.

[0042] See also Figure 1In one embodiment of the noise testing experimental device, the moving end of the lifting mechanism 4 is connected to the mounting plate 6, and all the top rods 5 are fixed on the mounting plate 6. The movement of the lifting mechanism 4 drives all the top rods 5 to move, and each top rod 5 works in conjunction with each other and moves in unison. More specifically, one end of each top rod 5 is fixed to the mounting plate 6, and the other end of each top rod 5 is used to be inserted into the silencer cavity 30 of the silencer base 3. In this embodiment, the cavity height changes of all silencer cavities 30 are consistent. Of course, the end of the top rod 5 used to insert into the silencer base 3 can be on the same plane or not on the same plane, which is not specifically limited here.

[0043] Optionally, see Figure 5 In one embodiment of the mounting plate 6, the mounting plate 6 has a plurality of circular hole arrays 61 with different diameters to accommodate different types of test pieces. The centers of the circular hole arrays 61 are the same, which is the center of the mounting plate 6. The diameter of the circular hole arrays 61 gradually increases from the center of the mounting plate 6 to the edge of the mounting plate 6. Each push rod 5 is fixed in a circular hole of the same circular hole array 61. The diameters of the circular holes of different circular hole arrays 61 may be the same or different.

[0044] In another embodiment of the noise testing experimental device, there are multiple lifting mechanisms 4, and the moving end of each lifting mechanism 4 is connected with one push rod 5, two push rods 5, three push rods 5, etc. In this way, a single, two or more push rods 5 can be controlled respectively. In this way, it is more convenient to verify the noise reduction effect when the heights of the various silencer cavities 30 in the silencer base 3 are different.

[0045] In the lifting mechanism 4 in any of the above embodiments, the lifting mechanism 4 may be any mechanism capable of outputting linear motion, such as a screw mechanism, a cylinder mechanism, a linear motor mechanism, or the like.

[0046] Optionally, see Figure 1 , Figure 6 and Figure 7 The lead screw mechanism includes a lifting motor 41, a lead screw 45 and a lead screw nut 46. The lead screw 45 is connected to the rotating shaft of the lifting motor 41 and rotates with the rotating shaft. The lead screw nut 46 on the lead screw 45 is threadedly matched with the lead screw 45. When the lead screw 45 rotates, the lead screw nut 46 moves linearly. The push rod 5 realizes its linear motion through the movement of the lead screw nut 46. When all the push rods 5 are controlled by a lead screw mechanism, the lead screw nut 46 is fixed on the mounting plate 6, and all the push rods 5 are also fixed on the mounting plate 6. In this way, the movement of the lead screw nut 46 can make all the push rods 5 move together.

[0047] Optionally, the screw mechanism is arranged on the orifice plate method test bench 1, one end of the screw 45 is connected to the lifting motor 41, and the other end is supported on the orifice plate method test bench 1 through a bearing 47, so that the screw 45 can rotate relative to the orifice plate method test bench 1, and the bearing 47 has a supporting effect on the screw 45.

[0048] See also Figure 6 In one embodiment of the screw mechanism, the screw mechanism includes a lifting motor 41, a screw 45 and a screw nut 46, and also includes a lifting plate 43 and a guide rod 44. The lifting plate 43 is fixed to the screw nut 46 and moves with the screw nut 46. The guide rod 44 is arranged through the lifting plate 43. When the screw 45 and the screw nut 46 move, the guide rod 44 remains stationary. The function of the guide rod 44 is to guide the screw nut 46 to make the movement of the screw nut 46 more stable. Among them, the length direction of the guide rod 44 is parallel to the length direction of the screw 45. More specifically, when the screw 45 is vertically arranged and the screw nut 46 moves in the vertical direction, the lifting plate 43 is horizontally arranged so that it has space for the guide rod 44 to pass through. When the screw mechanism of this embodiment also includes a mounting plate 6, the mounting plate 6 is fixedly connected to the lifting plate 43.

[0049] Furthermore, the screw mechanism also includes a motor mounting seat 42 , the lifting motor 41 is mounted on the motor mounting seat 42 , one end of the guide rod 44 is fixed to the motor mounting seat 42 , and the other end of the guide rod 44 is fixed to the orifice plate method test bench 1 .

[0050] See also Figure 1 In one embodiment of the noise test experimental device, an annular holder 2 is fixed on the orifice plate method test bench 1, a noise elimination matrix 3 is arranged in the annular holder 2, and a test piece 010 is arranged in the noise elimination matrix 3. The noise elimination matrix 3 is annular, and the test piece 010 is arranged in the area surrounded by the noise elimination matrix 3. The setting of the annular holder 2 provides a relatively closed environment for the noise test, thereby improving the accuracy of the test results.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. Noise test experimental device, characterized by: The invention comprises a perforated plate method test bench for placing a test piece, a muffler base for reducing the noise of the test piece, a lifting mechanism arranged on the perforated plate method test bench, and a push rod connected to the lifting mechanism, wherein the muffler base has a muffler cavity arranged opposite to the push rod, and the push rod moves with the lifting mechanism to change the length of the push rod extending into the muffler cavity and the cavity height of the muffler cavity; The number of the push rods and the number of the muffler cavities are both multiple, and the number of the push rods is the same as the number of the muffler cavities; The push rods are arranged in a ring shape, the muffler base is in a ring shape, and the muffler cavities are arranged in a ring shape in the muffler base. The tested object is arranged in the muffler base, so that the muffler cavities are arranged in a ring shape on the periphery of the tested object. The moving end of the lifting mechanism is connected to a mounting plate, and the ends of each of the push rods are fixed to the mounting plate; the mounting plate is provided with a plurality of circular hole arrays with different diameters to accommodate various types of test pieces, and each of the push rods is fixed in a circular hole of the same circular hole array, and the diameter of the circular hole array gradually increases from the center of the mounting plate to the edge of the mounting plate.

2. The noise test experimental device according to claim 1, characterized in that: There are multiple lifting mechanisms, and the moving end of each lifting mechanism is connected to at least one push rod.

3. The noise test experimental device according to claim 1 or 2, characterized in that: The lifting mechanism is a screw mechanism, a cylinder mechanism or a linear motor mechanism.

4. The noise test experimental device as claimed in claim 3, characterized in that: The screw mechanism includes a lifting motor, a screw driven to rotate by the lifting motor, and a screw nut connected to the screw, wherein the screw nut is a moving end of the screw mechanism.

5. The noise test experimental device as claimed in claim 4, characterized in that: The screw mechanism also includes a lifting plate and a guide rod, the lifting plate is fixed to the screw nut, the guide rod is penetrated by the lifting plate, and the length directions of the guide rod and the screw are parallel.

6. The noise testing experimental device according to claim 1, characterized in that: An annular holder is fixed on the orifice plate method test bench, the silencing matrix is ​​arranged in the annular holder, and the tested object is arranged in the silencing matrix.

7. The noise test experimental device according to claim 6, characterized in that: The measured object is a motor, and the noise-absorbing substrate is arranged on the outer periphery of the stator of the motor.

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