CN204703984U - Impedance composite muffler - Google Patents

Abstract

The utility model discloses an impedance compound muffler, which comprises a cavity structure composed of a shell, a front end cover and a rear end cover. A chamber, a second chamber, a third chamber and a fourth chamber; the first chamber is arranged with an inlet pipe; the fourth chamber is arranged with an outlet pipe; An insertion tube communicates with the first chamber and the second chamber; a perforated pipe is fixed on the partition II and partition III, the inlet of the perforated pipe is located in the second chamber, the outlet is located in the fourth chamber, and the perforated pipe is located in the second chamber. Small holes are uniformly arranged in the middle area of the three-chamber part. The utility model greatly reduces the low and medium frequency noise of the airflow through the reasonable combination of expansion and resonance while taking into account the high frequency noise reduction effect, and obtains a larger noise reduction amount and a wider noise reduction frequency band; it has lower pressure loss and less power consumption. ; The structure is simple and easy, the processing is convenient, and it has good economic performance.

Description

Impedance Composite Muffler

technical field

The utility model relates to a muffler for engineering machinery, in particular to an impedance compound muffler.

Background technique

The muffler is a device that attenuates air transmission and allows airflow to pass through. It is installed on the engine exhaust pipe. Its main function is to reduce the exhaust noise of the engine, reduce vibration, reduce the noise near the driver's ears in the cab and the radiation noise outside the machine, and improve the performance of the driver. operating comfort. The design of the muffler should take into account the requirements of its acoustic performance, aerodynamic performance and economy.

In the existing diesel engine mufflers, in order to obtain good noise reduction, the structural design is usually more complicated, the air flow resistance is large, the cost increases and the engine power loss increases, and the fuel consumption increases, resulting in greatly reduced aerodynamic performance and pollution. environment; and there are few structures in existing mufflers that can effectively reduce low-frequency noise, and low-mid-frequency exhaust noise is the main noise source of the whole machine.

Contents of the invention

The purpose of this utility model is to solve the problems existing in the existing diesel engine muffler for engineering machinery. The utility model provides an impedance compound muffler, which can greatly improve the muffler's low and middle frequency band noise reduction while ensuring low pressure loss and economy. performance.

In order to solve the problems of the prior art and achieve the above purpose, the utility model impedance compound muffler includes a cavity structure composed of a shell, a front end cover and a rear end cover, and the cavity structure is composed of a partition I, a partition II and partition III are divided into a first chamber, a second chamber, a third chamber and a fourth chamber; the first chamber is arranged with an inlet pipe; the fourth chamber is arranged with an outlet pipe; the A plurality of insertion tubes are arranged on the partition I to communicate with the first chamber and the second chamber; a perforated pipe is fixed on the partition II and III, the inlet of the perforated pipe is located in the second chamber, and the outlet is located in the fourth chamber. The chamber, the perforated tube is uniformly arranged with small holes in the middle area of the third chamber part.

As a further improvement of the utility model, there are four insertion tubes, which are welded with the partition I and distributed evenly along the circumference, and each insertion tube is staggered by 45 degrees from the axial section of the casing. Ensure that the airflow is relatively uniform, which is beneficial to reduce the airflow resistance and improve the noise reduction effect.

As a preferred solution of the present invention, the length of the outlet of the insertion tube is 1/2 of the length of the second chamber, which can ensure the peak noise reduction of the transmission loss curve and make the noise reduction effect better.

As a proposal of the present utility model, the two ends of the perforated pipe are welded together with the separator II and the separator III. Further, in order to avoid the eddy current phenomenon and reduce the pressure loss, the shape of the inlet of the perforated pipe is trumpet-shaped.

In order to achieve an ideal noise reduction effect, reduce airflow resistance, and reduce pressure loss, as a preferred solution of the present invention, the inlet length of the perforated pipe is 1/4 of the length of the second chamber, and the length of the outlet is the length of the fourth chamber. 1/2 of.

As a further improvement of the utility model, a partition IV is arranged in the fourth chamber, and a fifth chamber is formed in the housing, and small holes are evenly distributed on the partition IV, which communicates with the fourth chamber and the fifth chamber. The fifth chamber is filled with porous sound-absorbing material. The noise reduction effect is further improved, and the use of porous materials can simultaneously take into account the high-frequency noise reduction performance.

In order to facilitate the installation and use of the muffler, the utility model further has a mounting seat welded under the housing.

The utility model uses four partitions to divide the housing into five chambers. Since the airflow velocity entering the first chamber of the muffler is relatively high, in order to ensure smoother air flow, it can enter the second chamber smoothly, prevent backflow, and at the same time prevent Excessive pressure loss is generated to reduce the exhaust back pressure. Several insertion pipes are arranged on the partition I to communicate with the first and second chambers, and a perforated pipe is arranged between the partition II and the partition III. The entrance of the perforated pipe is located in the second chamber. chamber, the outlet is located in the fourth chamber, when the airflow flows from the pipeline to the cavity, the cross-sectional area changes, and the diameter of the cavity becomes larger from the pipeline with a smaller diameter, in the first chamber, the second chamber, the second chamber The expansion cavity is formed in the four chambers. Depending on the sudden change of the section of the pipe and the length of the pipe, the sound wave propagating forward and the sound wave reflected by each wall interfere with each other in the expansion cavity. By setting different lengths and expansion ratios of the expansion cavity, the ideal noise-abneance frequency can be obtained. The lower anechoic peak and less passing frequency, the perforated part of the perforated tube forms a resonance cavity in the third chamber, and the airflow flows to the third chamber through the small holes on the perforated tube to form multiple Helmholtz resonance cavities. The resonance of the air column produces severe friction, and the resonance cavity absorbs a large amount of sound energy. The ideal resonance frequency of the resonance cavity is obtained by setting the perforation rate of the perforated tube, and a standing wave is formed in the resonance cavity to achieve the effect of eliminating low-frequency noise. In the fifth chamber It is filled with porous sound-absorbing material, and the sound energy is consumed through friction in the pores of the porous material into heat energy, which further improves the noise reduction effect, and the use of porous materials can simultaneously take into account the high-frequency noise reduction performance. The utility model greatly reduces the low and medium frequency noise of the airflow through the reasonable combination of the expansion and resonance forms, and at the same time takes into account the high frequency silencing effect, obtains a large amount of silencing and a wider silencing frequency band; has lower pressure loss and less power consumption ; The structure is simple and easy, the processing is convenient, and it has good economic performance.

Description of drawings

Fig. 1 is the structural representation of the utility model;

Fig. 2 is a structural three-dimensional structure diagram of the utility model;

In Fig. 1: 1. inlet pipe; 2. rear end cover; 3. shell; 4. first chamber; 5. insertion pipe; 6. second chamber; 7. perforated pipe; 8. third chamber ;9, outlet pipe; 10, fourth chamber; 11, fifth chamber; 12, front cover; 13, porous sound-absorbing material; 14, partition IV; 15, partition III; 16, mounting seat; 17 , Partition II; 18, Partition I.

Detailed ways

In order to enable those skilled in the art to better understand the solution of the utility model, the utility model will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1, the utility model is an impedance compound muffler, which includes a cavity structure composed of a housing 3, a front end cover 12 and a rear end cover 2. The cavity structure is composed of a partition I18, a partition II17 and a partition Plate III 15 is divided into a first chamber 4, a second chamber 6, a third chamber 8 and a fourth chamber 10; the first chamber 4 is arranged with an inlet pipe 1; the fourth chamber 10 is arranged with an outlet pipe 9; A plurality of insertion tubes 5 are arranged on the partition I18, communicating with the first chamber 4 and the second chamber 6; a perforated tube 7 is fixed on the partition II17 and the partition III15, and the entrance of the perforated tube 7 is located in the second chamber 6, The outlet is located in the fourth chamber 10, and the perforated pipe 7 is evenly arranged with small holes in the middle area of the third chamber 8.

The shell 3 is divided into five chambers by four partitions, several insertion tubes 5 are arranged on the partition I to communicate with the first and second chambers, a perforated pipe 7 is arranged between the partition II7 and the partition III15, and the The airflow exhausted by the engine enters the inlet pipe 1 and then passes through the first chamber 4, the second chamber 6, the third chamber 8, the fourth chamber 10 and the fifth chamber 11 to reduce the exhaust noise, and finally the outlet Tube 9 exits. When the air flow flows from the insertion tube 5 to the second cavity, and when the perforated tube 7 flows to the fourth cavity, the air flow enters the cavity with a larger diameter from the pipe with a smaller diameter, and the cross-sectional area changes. The expansion cavity is formed in the expansion cavity, the second cavity, and the fourth cavity. The expansion cavity depends on the sudden change of the section of the pipeline and the length of the pipeline, so that the sound waves propagating forward and the sound waves reflected by each wall interfere with each other. By setting different expansion cavity lengths and Expansion ratio, to obtain the peak attenuation and less passing frequency at the ideal attenuation frequency, the perforated part of the perforated tube 7 forms a resonant cavity in the third chamber 8, and the airflow flows to the third chamber through the small hole on the perforated tube 7 8. Multiple Helmholtz resonant cavities are formed, and severe friction is generated through the resonance of the air column, and the resonant cavities absorb a large amount of sound energy. Through the reasonable combination of expansion and resonance, the airflow can greatly reduce the low and medium frequency noise while taking into account the high frequency noise reduction effect, so as to obtain a larger noise reduction amount and a wider noise reduction frequency band.

On the basis of the above-mentioned structure, the utility model also has the following further embodiments, as shown in Figure 2, the insertion tube 5 is set to four, welded together with the partition I18, evenly distributed along the circumference, and each insertion tube 5 It is staggered by 45 degrees with the axial section of the housing 3 . Here, four insertion tubes 5 are taken as an example. The insertion tubes 5 and the axial section of the housing 3 are staggered by 45 degrees, so that the insertion tubes 5 are kept distributed up and down on the partition I18 as two insertion tubes 5, so that when the air flow flows from the inlet tube 1. When entering, two insertion tubes 5 can enter from the bottom at the same time to ensure relatively uniform airflow, which is beneficial to reduce airflow resistance and improve the noise reduction effect. , when the airflow enters from the inlet pipe 1, the flow rate of the airflow through each insertion pipe is quite different, which invisibly increases the resistance of the airflow and reduces the effect of noise reduction.

The length of the outlet of the insertion tube 5 of the utility model is preferably 1/2 of the length of the second chamber 6, which can ensure the peak value of the silencing of the transmission loss curve and make the silencing effect better. The two ends of the perforated pipe 7 are welded together with the separator II 17 and the separator III 15, and the inlet shape of the perforated pipe 7 is trumpet-shaped, which can effectively avoid eddy current phenomenon and reduce pressure loss. The length of the entrance of the perforated pipe 7 is 1/4 of the length of the second chamber 6. This is to make the entrance closer to the third chamber, which facilitates the flow of air into the third chamber and reduces air resistance. The length of the outlet is preferably the fourth 1/2 of the chamber length can ensure the peak value of the transmission loss curve and make the noise reduction effect better.

A partition IV14 is provided in the fourth chamber 10, and a fifth chamber 11 is formed in the housing 3. Small holes are evenly distributed on the partition IV14, communicating with the fourth chamber 10 and the fifth chamber 11. The fifth chamber 11 is filled with porous sound-absorbing material 13 . Acoustic energy is dissipated by conversion into heat energy through friction in the pores of the porous material. The noise reduction effect is further improved, and the use of porous materials can simultaneously take into account the high-frequency noise reduction performance.

In addition, a mounting base 16 is welded under the housing 3 for the convenience of installing the muffler during use.

Certainly, the above-mentioned embodiments are only preferred solutions of the present invention, and are not limited thereto. On this basis, targeted adjustments can be made according to actual needs, so as to obtain different implementation modes. Since there are many ways of possible realization, it is not necessary to give examples one by one here.

Claims (7)

1. an impedance composite muffler, comprises the cavity body structure be made up of housing (3), front cover (12) and rear end cover (2), it is characterized in that,

Described cavity body structure inner route clapboard I (18), dividing plate II (17) and dividing plate III (15) are divided into the first chamber (4), the second chamber (6), the 3rd chamber (8) and the 4th chamber (10);

Described first chamber (4) is furnished with inlet tube (1);

Described 4th chamber (10) is furnished with outer pipe (9);

Described dividing plate I (18) is provided with multiple Inserting Tube (5), is communicated with the first chamber (4) and the second chamber (6);

Described dividing plate II (17) and dividing plate III (15) are fixed with a perforated pipe (7), perforated pipe (7) import is positioned at the second chamber (6), outlet is positioned at the 4th chamber (10), and perforated pipe (7) has aperture the 3rd chamber (8) part zone line is evenly distributed.

2. a kind of impedance composite muffler according to claim 1, it is characterized in that, described Inserting Tube (5) arranges four, welds together with dividing plate I (18), circumferentially be uniformly distributed, and each Inserting Tube (5) and housing (3) axial cross section are staggered 45 degree.

3. a kind of impedance composite muffler according to claim 1 and 2, is characterized in that, described Inserting Tube (5) outlet length is 1/2 of the second chamber (6) length.

4. a kind of impedance composite muffler according to claim 1, is characterized in that, described perforated pipe (7) two ends and dividing plate II (17), dividing plate III (15) weld together, and perforated pipe (7) entrance shape is horn-like.

5. a kind of impedance composite muffler according to claim 1 or 4, is characterized in that, described perforated pipe (7) entrance length is 1/4 of the second chamber (6) length, and outlet length is 1/2 of the 4th chamber (10) length.

6. a kind of impedance composite muffler according to claim 1, it is characterized in that, dividing plate IV (14) is provided with in described 4th chamber (10), the 5th chamber (11) is formed in housing (3), dividing plate IV (14) is evenly distributed with aperture, be communicated with the 4th chamber (10) and the 5th chamber (11), in described 5th chamber (11), be filled with sound-absorbing porous material (13).

7. a kind of impedance composite muffler according to claim 1, is characterized in that, is welded with fitting seat (16) under described housing (3).