Axial flow guide small hole noise reduction cover for motor

Abstract

The utility model relates to the technical field of motor noise reduction equipment, in particular to an axial flow guide small hole noise reduction cover for a motor, which comprises a noise reduction cover body, the noise reduction cover body comprises a first air guide wall and a second air guide wall, a distance is reserved between one end of the first air guide wall and one end of the second air guide wall to form an air inlet, and the other ends of the first air guide wall and the second air guide wall are connected into a whole. An air outlet hole group for air outlet is formed in the second air guide wall, the air outlet hole group comprises two or more rows of silencing holes, and the cross sectional areas of the silencing holes are gradually increased in the direction from the second air guide wall to the first air guide wall. The axial flow guide small hole noise reduction cover for the motor has the effect of improving the high efficiency of the axial flow guide small hole noise reduction cover for the motor in the using process.

Description

Technical Field

[0001] This application relates to the field of motor silencing equipment technology, and in particular to a motor axial flow guide hole silencing cover. Background Technology

[0002] With the improvement of people's living standards, vacuum cleaners have become an indispensable household appliance. People are particularly sensitive to the operating noise of these appliances. Therefore, to improve the noise of vacuum cleaner motors, soundproof covers are often added to achieve better noise reduction. However, several factors need to be considered: motor heat dissipation: impedance-type soundproof covers require filling with sound-absorbing materials, affecting heat dissipation; soundproof cover manufacturing: micro-perforated plates require ultra-thin metal materials with micro-holes less than 1mm in diameter, which is difficult and costly; and the soundproof cover's fit with the overall machine: active soundproofing requires corresponding detection of the sound source, which is difficult to achieve in the limited space of a vacuum cleaner. Therefore, small-hole soundproof covers are the most suitable. Small-hole soundproof covers divide the total outflow area into multiple small holes while maintaining a constant total area. This disperses the pressure drop, reducing airflow velocity and thus lowering sound power. Furthermore, the sound frequency of the gas emitted through the small holes shifts to a frequency range inaudible to the human ear.

[0003] A Chinese utility model patent with application number CN202320303907.X discloses a fan silencing structure. One aspect of this silencing structure is a radially vented small-hole silencing cover that achieves noise reduction by allowing the outlet airflow to flow out through small side holes. In this radially vented small-hole silencing cover, most of the fluid is first thrown axially, impacting the bottom of the silencing cover before being squeezed out through the side holes. This significantly affects motor efficiency. Furthermore, because the bottom of the radially vented small-hole silencing cover is closed, the high-speed impact and compression of the fluid at the bottom can cause structural vibration, potentially inducing strength problems or new noise issues. Utility Model Content

[0004] In order to improve the efficiency of the axial flow guide orifice silencing cover for motors during use, this application provides an axial flow guide orifice silencing cover for motors.

[0005] This application provides a axial flow guide hole silencer for an electric motor, which adopts the following technical solution:

[0006] A motor axial airflow guide hole silencer includes a silencer body, which includes a first air guide wall and a second air guide wall. The first air guide wall and the second air guide wall are spaced apart at one end to form an air inlet, and the other end is connected as a whole. An air outlet hole group is opened on the second air guide wall for air outlet. The air outlet hole group includes two or more rows of silencer holes. The cross-sectional area of ​​the silencer holes gradually increases in the direction from the second air guide wall to the first air guide wall.

[0007] By adopting the above technical solution, most of the airflow blown out by the motor is collected and guided into the air inlet on the silencer body. Because the airflow speed gradually increases from near to far with the motor rotor as the reference, the airflow velocity will be different. The airflow enters the silencer and enters the small holes step by step along the second air guide wall. The airflow speed in the outer ring is fast and the airflow speed in the inner ring is relatively slow, which corresponds to the design of the large hole in the outer ring and the small hole in the inner ring. This ensures that the axial outflow velocity of the airflow is relatively consistent, thereby reducing the loss of efficiency.

[0008] In one specific implementation, the second air guide wall is configured as a curved surface, and the silencing holes include a first silencing hole and a second silencing hole. The first silencing hole is located further away from the first air guide wall than the second silencing hole, and the cross-sectional area of ​​the first silencing hole is smaller than the cross-sectional area of ​​the second silencing hole.

[0009] By adopting the above technical solution, the second air guide wall is set as a curved surface, which facilitates the flow of gas. This allows most of the airflow from the motor outlet to be collected and guided into the silencer, where it is silenced. This enhances the efficiency of the silencer during use. The combination of the curved surface and the varying sizes of the small holes ensures a uniform distribution of airflow velocity, thus solving the problem of excessive efficiency loss. Furthermore, the bottom opening solves the strength or noise problems caused by the impact and compression of the airflow.

[0010] In one specific implementation, the first silencing hole and the arc-shaped sidewall of the second air guide wall on the side away from the first air guide wall form an opening.

[0011] In one specific implementation, the second silencing hole forms an opening with the arc-shaped sidewall of the second air guide wall near the first air guide wall.

[0012] By adopting the above technical solution, the first and second silencing holes are opened on the second air guide wall, which increases the diameter of the holes, which facilitates airflow and enhances the silencing effect.

[0013] In one specific implementation scheme, a third silencing hole is provided on the second air guide wall. The third silencing hole is located on the side of the second silencing hole away from the first silencing hole. The third silencing hole is located near the connection position between the first air guide wall and the second air guide wall. The cross-sectional area of ​​the third silencing hole is larger than the cross-sectional area of ​​the second silencing hole.

[0014] By adopting the above technical solution and adding a third silencing hole, the airflow can easily flow out from the connection position after passing through the first and second air guide walls, thereby enhancing the airflow performance within the silencing cover.

[0015] In one specific implementation, the first air guide wall is provided with sound-insulating louvers, which are arranged in a circular pattern on the first air guide wall.

[0016] By adopting the above technical solution and adding soundproof louvers, on the one hand, some airflow is guided to flow out through the soundproof louvers, and the airflow is further slowed down by friction. On the other hand, the soundproof louvers reflect sound waves by their inclined surfaces, which can prevent the propagation of direct sound. The noise reduction capability of the soundproof cover is further increased by adding soundproof louvers to the soundproof holes.

[0017] In one specific implementation, the spacing between the soundproof louvers is 0.8 mm.

[0018] In one specific implementation, the silencer body is provided with an avoidance opening, and a reinforcing plate is installed on the silencer body at the avoidance opening position, the reinforcing plate connecting the first air guide wall and the second air guide wall together.

[0019] By adopting the above technical solution, the addition of reinforcing plates helps to enhance the stability of the soundproof cover's main structure.

[0020] In summary, this application includes at least one of the following beneficial technical effects:

[0021] 1. When the motor is running, most of the airflow blown out by the motor is collected and guided into the air inlet on the silencer body. The airflow enters the silencer and enters the small holes step by step along the curved surface of the second air guide wall. The airflow speed in the outer ring is fast and the airflow speed in the inner ring is relatively slow, which corresponds to the design of the large holes in the outer ring and the small holes in the inner ring. This ensures that the axial outflow speed of the airflow is relatively consistent, thereby reducing efficiency loss. The airflow flows out through the sound insulation louvers, and the airflow is further slowed down by friction. The sound insulation louvers reflect the sound waves by their inclined surfaces, which can block the propagation of direct sound. The sound insulation of the small holes and the sound insulation of the sound insulation louvers further increase the noise reduction capability of the silencer. Attached Figure Description

[0022] Figure 1 This is a schematic diagram illustrating the positional relationship of the silencer cover mounted on the motor according to an embodiment of this application.

[0023] Figure 2 This is a cross-sectional view of the muffler and motor according to an embodiment of this application.

[0024] Figure 3 This is a schematic diagram illustrating the internal structure of the silencer cover body in an embodiment of this application.

[0025] Figure 4 This is a schematic diagram of the external structure of the silencer cover body, which embodies an embodiment of this application.

[0026] Figure 5This is a schematic diagram illustrating the arrangement of the air guide holes on the body of the muffler in an embodiment of this application.

[0027] Figure 6 This is a cross-sectional view of the sound-absorbing cover body according to an embodiment of this application.

[0028] Reference numerals in the attached drawings: 1. Silencing cover body; 11. First air guide wall; 12. Second air guide wall; 13. Air outlet group; 131. First silencing hole; 132. Second silencing hole; 133. Third silencing hole; 14. Sound insulation louver; 15. Reinforcing plate. Detailed Implementation

[0029] The following is in conjunction with the appendix Figure 1-6 This application will be described in further detail.

[0030] This application discloses a noise-reducing cover with axial flow-guiding holes for a motor, referring to... Figure 1 , Figure 2 and Figure 3 The silencing cover body 1 includes a first air guide wall 11 located on the outer ring and a second air guide wall 12 located on the inner ring. The first air guide wall 11 and the second air guide wall 12 are separated at one end to form an air inlet, and the other end is connected together to form a closed annular whole. The second air guide wall 12 is provided with an air outlet hole group 13 for air outlet, and the air outlet hole group 13 includes two or more rows of silencing holes.

[0031] See attached document Figure 3 To be continued Figure 6 The second air guide wall 12 is configured with an S-shaped curved surface. The silencing holes are divided into a first silencing hole 131 and a second silencing hole 132. The first silencing hole 131 is located close to the inner wall of the second air guide wall 12, forming an opening along the arc-shaped surface of the inner wall of the second air guide wall 12. The second silencing hole 132 is located closer to the first air guide wall 11 than the first silencing hole 131, and also forms an opening along the arc-shaped surface of the outer wall of the second air guide wall 12. A third silencing hole 133 is provided on the second air guide wall 12. The third silencing hole 133 is located on the side of the second silencing hole 132 away from the first silencing hole 131. The third silencing hole 133 is located near the connection position of the first air guide wall 11 and the second air guide wall 12. The third silencing hole 133, the second silencing hole 132 and the first silencing hole 131 are all on the same straight line. The cross-sectional area of ​​the third silencing hole 133 is larger than the cross-sectional area of ​​the second silencing hole 132, and the cross-sectional area of ​​the second silencing hole 132 is larger than the cross-sectional area of ​​the first silencing hole 131.

[0032] In this embodiment, the cross-sections of the first silencing hole 131, the second silencing hole 132, and the third silencing hole 133 are all elliptical, and the total area of ​​the cross-sections satisfies the following relationship: Where: S is the opening area of ​​the orifice; A is the medium coefficient: A = 13 for dry air, oxygen, hydrogen, etc.; A = 13.4 for superheated steam; A = 14 for saturated steam; G is the weight flow rate of the exhaust gas; V1 is the specific volume of the gas at the inlet of the silencer; p1 is the pressure of the gas at the inlet of the silencer; μ is the flow section coefficient, which is 1.8-2.0 when the diameter-to-length ratio is less than 0.5. Preferably, the area of ​​a single orifice is best in the range of 1mm-3mm.

[0033] When the motor is running, the impeller on the motor draws in outside air to do work. Most of the airflow blown out by the motor is collected by the silencer body 1 and guided into the air inlet on the silencer body 1. Because the airflow speed gradually increases from near to far with the motor rotor as the reference, the airflow velocity will be different. The airflow enters the silencer and enters the small holes step by step along the S-shaped curved surface of the second air guide wall 12. The airflow speed in the outer ring is fast and the airflow speed in the inner ring is relatively slow, which corresponds to the design of the large hole in the outer ring and the small hole in the inner ring. This ensures that the axial outflow velocity of the airflow is relatively consistent, thereby reducing the loss of efficiency.

[0034] In addition, the small hole can reduce the exhaust pressure and exhaust speed, and has a large acoustic impedance. Therefore, when sound energy is injected through the small hole, there will be a large loss. The small hole also has a frequency upsampling effect, pushing most of the sound energy to the frequency range that the human ear is not sensitive to or the ultrasonic frequency range that the human ear cannot perceive, thus greatly reducing noise. The first silencing hole 131 and the second silencing hole 132 form an opening on the second air guide wall 12, which can facilitate air flow and enhance the silencing effect.

[0035] In this embodiment, the tangent at the inlet of the second guide wall 12 of the S-shaped curved surface forms an angle of 28.6° with the axial direction, and the tangent at the outlet forms an angle of 36.6° with the axial direction. The axial length of the curve, i.e. the total length of the silencer channel, is 14.6 mm, and the radial length, i.e. the width of the silencer channel, is 4.3 mm. In this design, the width of the silencer channel is 4 / 5 of the width of the motor channel outlet. By controlling the curve parameters, most of the airflow from the motor outlet can be collected and guided into the silencer for noise reduction, thereby enhancing the efficiency of the silencer during use.

[0036] In this embodiment, the second air guide wall 12 of the silencing cover is not limited to a curved surface. The cross-section of the silencing hole can be polygonal or irregular in shape without affecting the structure.

[0037] The first air guide wall 11 is equipped with sound-insulating louvers 14. Each sound-insulating louver 14 is composed of a sheet with a thickness of 1.2 mm, a width of 3 mm, and a length of 9.7 mm. From the axial direction, each louver forms a 30° angle with the tangent of the outer circle of the silencer cover. The louvers are arranged in a circular pattern with a spacing of 0.8 mm between them and an inclination angle of 30 degrees. The inclination direction is in line with the direction of airflow out of the motor. By adding sound-insulating louvers 14, on the one hand, some airflow is guided to flow out through the sound-insulating louvers 14, and the airflow is further slowed down by friction. On the other hand, the sound-insulating louvers 14 reflect sound waves by their inclined surfaces, which can prevent the propagation of direct sound. The sound-insulating louvers 14, combined with the sound-insulating louvers 14, further increases the noise reduction capability of the silencer cover.

[0038] The silencer body 1 has an opening for clearance. A reinforcing plate 15 is installed on the silencer body 1 at the clearance position. The reinforcing plate 15 connects the first air guide wall 11 and the second air guide wall 12 together, thereby enhancing the structural strength and stability of the silencer body 1.

[0039] The implementation principle of this application embodiment is as follows: When the motor is running, most of the airflow blown out by the motor is collected by the silencer body 1 and guided into the air inlet on the silencer body 1. The airflow enters the silencer and enters the small holes step by step along the S-shaped curved surface of the second air guide wall 12. The airflow speed in the outer ring is fast and the airflow speed in the inner ring is relatively slow, which corresponds to the design of the large holes in the outer ring and the small holes in the inner ring. This ensures that the axial outflow speed of the airflow is relatively consistent, thereby reducing the loss of efficiency. The airflow flows out through the sound insulation louvers 14, and the airflow is further slowed down by friction. The sound insulation louvers 14 reflect the sound waves by the inclined surface, which can block the propagation of direct sound. The sound insulation of the small holes and the sound insulation of the sound insulation louvers 14 further increase the noise reduction capability of the silencer.

[0040] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An axial flow hole silencer for a motor, characterized by: The muffler body (1) comprises a first air guide wall (11) and a second air guide wall (12), one end of which is left with a distance to form an air inlet, and the other end is connected as a whole, a group of air outlet holes (13) for air outlet are arranged on the second air guide wall (12), the group of air outlet holes (13) comprises two rows or more than two rows of sound attenuation holes, the cross-sectional area of the sound attenuation holes gradually increases in the direction from the second air guide wall (12) to the first air guide wall (11).

2. The axial flow ported sound shield for an electric machine of claim 1, wherein: The second air guide wall (12) is arranged as a curved surface, the sound attenuation holes include first sound attenuation holes (131) and second sound attenuation holes (132), the first sound attenuation holes (131) are arranged away from the first air guide wall (11) compared with the second sound attenuation holes (132), and the cross-sectional area of the first sound attenuation holes (131) is smaller than that of the second sound attenuation holes (132).

3. The axial flow ported sound shield for an electric machine of claim 2, wherein: The first sound attenuation holes (131) and the arc-shaped side wall of the second air guide wall (12) away from the first air guide wall (11) form an open mouth.

4. The axial flow ported sound shield for an electric machine of claim 2, wherein: The second sound attenuation holes (132) and the arc-shaped side wall of the second air guide wall (12) close to the first air guide wall (11) form an open mouth.

5. The axial flow ported sound shield for an electric machine of claim 2, wherein: The second air guide wall (12) is provided with third sound attenuation holes (133), the third sound attenuation holes (133) are arranged on the side of the second sound attenuation holes (132) away from the first sound attenuation holes (131), the third sound attenuation holes (133) are arranged close to the connection position of the first air guide wall (11) and the second air guide wall (12), and the cross-sectional area of the third sound attenuation holes (133) is greater than that of the second sound attenuation holes (132).

6. The axial flow ported sound shield for an electric machine of claim 1, wherein: The first air guide wall (11) is provided with sound insulation louvers (14), and the sound insulation louvers (14) are arranged in a circle on the first air guide wall (11).

7. The axial flow ported sound shield for an electric machine of claim 6, wherein: The interval between the sound insulation louvers (14) is 0.8mm.

8. The axial flow ported sound shield for an electric machine of claim 1, wherein: The muffler body (1) is provided with a avoiding port, the muffler body (1) is provided with a reinforcing plate (15) at the avoiding port, and the reinforcing plate (15) connects the first air guide wall (11) and the second air guide wall (12) together.

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