Air conditioner silencer based on polymer composite material injection molding and ultrasonic welding

Abstract

The air conditioner silencer based on polymer composite injection molding and ultrasonic welding comprises a silencer body, the silencer body is of a tubular structure, the hole diameters of the two ends of the silencer body are reduced, the silencer body is divided into a section A and a section B, and the section A and the section B are formed in an injection molding mode and welded into a whole through ultrasonic waves. And the welding surfaces of the section A and the section B are respectively provided with a self-locking head and a self-locking groove. According to the silencer, a common injection molding process and a conventional ultrasonic welding process can be used, and the production efficiency is improved by more than 5 times; the innovatively-designed ultrasonic welding end face is adopted, full fusion can be achieved under the effect of ultrasonic waves, and therefore the air tightness is guaranteed; the self-locking function is achieved, and pressure maintaining is not needed after the end faces are fused; a macromolecule and metal reinforcing material is adopted, and the pressure of 1.0 MPa of a conventional refrigerant pipeline of an air conditioner is met; the special-shaped metal pipe insert with the flame blocking piece is introduced and is directly connected with an air conditioning system pipeline in a mature copper-steel welding mode, and the silencer can be prevented from being burnt out by welding flames.

Description

Technical Field

[0001] The invention relates to the technical field of air conditioners, in particular to an air conditioner muffler based on polymer composite material injection molding and ultrasonic welding. Background Art

[0002] At present, most of the air conditioner outdoor units on the market use "resistance silencers" in their refrigeration systems (see Figure 1 ), used to reduce the noise of refrigerant in refrigeration pipelines. The resistance muffler is made of a small tube φ1 and a large diameter φ0. It uses the sudden increase in the cross section of the pipeline to emit sound waves in the opposite direction of the sound source to achieve a muffler effect. It has a good muffler effect on medium and low noise and has a simple structure. In order to ensure the muffler effect, the expansion ratio should be φ0 / φ1>4.

[0003] The traditional process of making mufflers is to use a metal with excellent ductility, such as a precious copper tube, on a special spinning machine to reduce the ends of the thicker copper tube φ0 to φ1 = 1 / 4φ0 to make a "copper muffler". Figure 1 .

[0004] The manufacturing process of traditional copper mufflers has the following two major disadvantages:

[0005] 1. Highly ductile metals, such as copper, must be used to achieve an expansion ratio of 1 / 4. The price of copper is >60,000 yuan / ton, and its density is relatively high (density 8.9) (stainless steel is 20,000 yuan / ton, density 7.8). The cost of a stainless steel muffler of the same size is only 30% of that of copper; however, stainless steel is more difficult to form;

[0006] 2. It requires a large number of special spinning equipment with low manufacturing efficiency. A single machine can only produce 2,500 units in two shifts (24 hours), and a monthly production capacity of only 65,000 units. For large air conditioner manufacturers (such as Midea and Gree), the monthly demand during the peak season is >10 million units, so >150 units are needed to meet production needs. Assuming the equipment price is 75,000 yuan / unit, an investment of >10 million yuan is required! Adding the equipment depreciation and the operator's salary, the processing cost remains high.

[0007] Therefore, the market urgently needs to discover a cheap, corrosion-resistant, good mechanical property (fatigue, fracture, strength), efficient and convenient air conditioning muffler manufacturing process and material process. Summary of the invention

[0008] In order to solve the above problems, the present invention discloses an air conditioner muffler based on polymer composite material injection molding and ultrasonic welding. The invention uses injection molding process and special welding technology, and replaces special spinning equipment with ordinary injection molding machine, without equipment investment, and greatly shortens the processing cycle of a single piece from 30s to 3s, and improves the efficiency by 10 times; selects a polymer + reinforced material (PA66 + GF30), which has a tensile strength of 180MPa, which is equivalent to copper; the linear expansion coefficient is 20μ / mk, which is equivalent to 17μ / mk of copper, and is suitable for R410a, R407C and R32 air conditioning pipeline environments; innovatively adopts the end face design with self-locking docking to ensure the ultrasonic welding. a,b,c The three sides are tightly welded to meet the air-tightness requirements of the air-conditioning system for the pipeline, and the self-locking structure can continuously apply pressure, eliminating the pressure holding time after welding. The overall welding time is shortened from 5s to 1.5s, and the efficiency is increased by 3 times. By embedding a metal tube with a fireproof baffle (such as 304 stainless steel), the polymer plastic silencer can be directly welded to the external refrigeration pipeline, and can effectively prevent the flame from burning the composite material body during welding.

[0009] The specific plan is as follows:

[0010] The air conditioner muffler based on polymer composite material injection molding and ultrasonic welding includes a muffler body, the muffler body is a tubular structure, the aperture of the two ends is reduced, and the characteristic is that the muffler body is divided into section A and section B, the section A and section B are respectively injection molded and ultrasonically welded, the welding surfaces of the section A and section B are respectively provided with self-locking heads and self-locking grooves, the self-locking heads and self-locking grooves are adapted and tightly pressed. The ultrasonic plastic welding technology in the present invention utilizes that when ultrasonic waves pass through the plastic contact surface, due to the large acoustic resistance at the interface, local high temperature will be generated, causing the plastic to melt rapidly in the area close to the contact surface, and the interface is solidified under the action of pressure to form a strong molecular chain, and the welding strength is close to the raw material strength. The quality of ultrasonic plastic welding depends on three factors: the amplitude of the transducer welding head, the applied pressure and the welding time, and the optimal parameters need to be adjusted according to the actual situation.

[0011] As a further improvement of the present invention, the muffler body is a high molecular nylon + 30% glass fiber composite muffler. It has excellent mechanical properties, tensile strength σ T =180MPa, thermal expansion coefficient α=20μ / Km. Strength performance and copper σ T=180MPa, α=17μ / Km is close. In the pipeline pressure of the air-conditioning R32 refrigerant system: under low pressure, its standard value is 0.5MPa, which is equivalent to 5 kg. Under high pressure, the pressure is 1.8MPa, which is equivalent to 18 kg. Under equilibrium, the pressure is 1MPa, which is 10 kg. The tensile strength of nylon + 30% glass fiber (PA66+GF30) reaches 180MPa, which is acceptable as the strength of the R32 air-conditioning system pipeline. The pipeline pressure of R410a and 407c is lower than that of R32, so they can both be used.

[0012] As a further improvement of the present invention, the self-locking head is provided with three end faces a, b and c for welding, wherein the end faces a and c are parallel to each other in annular shapes, and the outer diameter of the end face a is greater than the outer diameter of the end face c and is perpendicular to the ultrasonic injection direction, and the end face b is horn-shaped and is perpendicular to the ultrasonic injection direction. β The small aperture end is connected to the outer side of the c end face, and the self-locking groove is provided with a welding end face adapted to the self-locking head. The ultrasonic wave enters from the a end, passing through the interfaces a, b, and c. The sections a and c are perpendicular to the ultrasonic wave injection direction; the section b is perpendicular to the ultrasonic wave injection direction. β Angle, which is conducive to the reflection of ultrasonic waves. At the same time, t becomes t / Cos β , increase the contact area, and also improve the air tightness.

[0013] As a further improvement of the present invention, the a, b, and c end faces are continuous faces connected in sequence, and the inner side of the a end face is connected to the large-aperture end of the b end face.

[0014] As a further improvement of the present invention, the end faces a and b are connected by a cylindrical surface.

[0015] As a further improvement of the present invention, a pipe sleeve structure is provided at both ends of the muffler body, and a metal pipe for welding the muffler body to the copper pipe of the peripheral refrigeration system is embedded in the pipe sleeve structure. The metal pipe is formed as one piece with the muffler body during the injection molding process, and an annular flame baffle is provided on the outside of the middle part.

[0016] As a further improvement of the present invention, the metal tube is a 304 stainless steel tube, and the thermal conductivity coefficient λ=15W / mK, which is 1 / 25 of copper (λ=385W / mK), and the metal tube and the flame baffle are directly formed by metal cold heading.

[0017] As a further improvement of the present invention, the edge of the flame baffle is folded 90° toward the muffler body, which can better prevent the muffler body from being burned during welding.

[0018] As a further improvement of the present invention, the metal tube is a 304 stainless steel tube.

[0019] As a further improvement of the present invention, metal spiral wires are installed in the A section and the B section and are integrally injection molded to increase the elastic modulus of the muffler body.

[0020] As a further improvement of the present invention, a filter screen for filtering the refrigerant is installed between section A and section B.

[0021] The beneficial effects of the present invention are:

[0022] 1. The muffler of the present invention can use ordinary injection molding process and conventional ultrasonic welding process. It replaces the complex spinning equipment, does not require the investment of special equipment, and improves the production efficiency by more than 5 times;

[0023] 2. The innovatively designed ultrasonic welding end face allows the three faces a, b, and c to be fully fused under the action of ultrasound, thereby ensuring air tightness. In addition, the structure has a self-locking function, and there is no need to maintain pressure after the end faces are fused. The welding production cycle is shortened by 70%, and the efficiency is significantly improved.

[0024] 3. It uses polymer + metal reinforcement materials (PA66 + GF30), with a tensile strength of 180Mpa, excellent anti-fatigue properties, and a linear expansion coefficient of α = 20μ / Km, which is close to copper's 17μ / Km. Its mechanical properties meet the 1.0MPa pressure requirement of conventional air-conditioning refrigerant (R32, R410a, R407c) pipelines;

[0025] 4. By introducing a metal pipe insert with a flame baffle, the muffler can be directly connected to the external system pipeline using a mature copper-steel welding method, and can prevent the welding flame from burning the composite muffler. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic diagram of an existing reactive silencer.

[0027] Figure 2 It is a structural schematic diagram of the present invention.

[0028] Figure 3 It is a schematic diagram of the present invention being integrated by ultrasonic welding, wherein the arrow indicates the direction of the ultrasonic wave.

[0029] Figure 4 This is a schematic diagram of the welding of the three end faces a, b, and c in Example 1.

[0030] Figure 5 This is a schematic diagram of the welding of the three end faces a, b, and c in Example 2.

[0031] Figure 6 Schematic diagram of adding spiral wire to the present invention.

[0032] Figure 7This is a schematic diagram of the metal tube insert and its assembly with the muffler body in Example 1, the left figure is a diagram of the metal tube insert, and the right figure is an assembly diagram.

[0033] Figure 8 This is a schematic diagram of the metal tube insert and its assembly with the muffler body in Example 4, the left figure is a diagram of the metal tube insert, and the right figure is an assembly diagram.

[0034] List of reference numerals:

[0035] 1-A section, 2-B section, 3-metal tube, 4-flame baffle, 5-metal spiral wire. DETAILED DESCRIPTION

[0036] The present invention will be further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. Example 1

[0037] like Figure 2-4 As shown, the air conditioner muffler based on polymer composite material injection molding and ultrasonic welding includes a muffler body, the muffler body is a tubular structure, the aperture of the two ends is reduced, the muffler body is divided into section A 1 and section B 2, the A section and the B section are respectively injection molded and ultrasonically welded, the welding surfaces of the A section and the B section are respectively provided with a self-locking head and a self-locking groove, the self-locking head and the self-locking groove are adapted and tightly pressed. The ultrasonic plastic welding technology in the present invention utilizes that when ultrasonic waves pass through the plastic contact surface, due to the large acoustic resistance at the interface, local high temperature will be generated, causing the plastic to melt rapidly in the area close to the contact surface, and the interface is solidified under the action of pressure to form a strong molecular chain, and the welding strength is close to the raw material strength. The quality of ultrasonic plastic welding depends on three factors: the amplitude of the transducer welding head, the applied pressure and the welding time, and the optimal parameters need to be adjusted according to the actual situation.

[0038] In this embodiment, the muffler body is a nylon + 30% glass fiber polymer composite muffler. It has excellent mechanical properties and a tensile strength of σ T =180MPa, thermal expansion coefficient α=20μ / Km. Strength performance and copper σ T =180MPa, α=17μ / Km is close. In the pipeline pressure of the air-conditioning R32 refrigerant system: under low pressure, its standard value is 0.5MPa, which is equivalent to 5 kg. Under high pressure, the pressure is 1.8MPa, which is equivalent to 18 kg. Under equilibrium, the pressure is 1MPa, which is 10 kg. The tensile strength of nylon + 30% glass fiber (PA66+GF30) reaches 180MPa, which is acceptable as the strength of the R32 air-conditioning system pipeline. The pipeline pressure of R410a and 407c is lower than that of R32, so they can both be used.

[0039] In this embodiment, the self-locking head is provided with three end faces a, b, and c for welding, wherein the end faces a and c are parallel to each other in annular shapes, and the outer diameter of the end face a is greater than the outer diameter of the end face c and is perpendicular to the ultrasonic injection direction, and the end face b is horn-shaped and is perpendicular to the ultrasonic injection direction. β The small aperture end is connected to the outer side of the c end face, and the self-locking groove is provided with a welding end face adapted to the self-locking head. The ultrasonic wave enters from the a end, passing through the interfaces a, b, and c. The sections a and c are perpendicular to the ultrasonic wave injection direction; the section b is perpendicular to the ultrasonic wave injection direction. β Angle, which is conducive to the reflection of ultrasonic waves. At the same time, t becomes t / Cos β , increase the contact area, and also improve the air tightness.

[0040] In this embodiment, the a, b, and c end faces are continuous faces connected in sequence, and the inner side of the a end face is connected to the large-aperture end of the b end face.

[0041] In this embodiment, if Figure 7 As shown, a pipe sleeve structure is provided at both ends of the muffler body, and a metal pipe for welding the muffler body to the copper pipe of the peripheral refrigeration system is embedded in the pipe sleeve structure. The metal pipe is formed as one body with the muffler body during the injection molding process, and an annular flame baffle 4 is provided on the outside of the middle.

[0042] In this embodiment, the metal tube is a 304 stainless steel tube with a thermal conductivity coefficient of λ=15W / mK, which is 1 / 25 of copper (λ=385W / mK). The metal tube and the flame baffle are directly formed by metal cold heading. Example 2

[0043] In this embodiment, if Figure 5 As shown, the end faces a and b are connected by a cylindrical surface. The remaining features of this embodiment are the same as those of embodiment 1. Example 3

[0044] In this embodiment, if Figure 6 As shown, metal spiral wires 5 are installed in the A section and the B section and are integrally injection molded to improve the elastic modulus of the muffler body. The remaining features of this embodiment are the same as those of the first embodiment. Example 4

[0045] In this embodiment, if Figure 8 As shown, the edge of the flame stopper is folded 90° toward the muffler body, which can better prevent the muffler body from being burned during welding. The remaining features of this embodiment are the same as those of embodiment 1. Example 5

[0046] In this embodiment, a filter screen for filtering the refrigerant is installed between section A and section B. The remaining features of this embodiment are the same as those of embodiment 1.

[0047] The production capacity and economic effect of the present invention are:

[0048] 1. The present invention uses ordinary injection molding technology to make silencers, and there is no need to purchase special equipment; for example, if each injection mold has 36 cavities, 18 A segments and 18 B segments, and the injection cycle is 36 seconds, then the processing cycle of each set of A+B silencers is 2 seconds, and the daily production capacity of double shifts for 24 hours is 43,000 pieces, and the monthly production capacity of 30 days is 1.3 million pieces. 10 injection molding machines can meet the monthly production demand of 13 million pieces;

[0049] 2. The present invention uses ultrasonic welding, and the A+B sections are pre-installed and self-locked in place, and prestress is applied. The loading + welding time is calculated as 2s / set, which matches the injection molding, and the monthly production capacity is 1.3 million pieces in 30 days. 10 welding machines can meet the monthly production demand of 13 million;

[0050] 3. The unit price of the main PA66+GF30 material of the present invention is 20,000 yuan / ton, which is 33% of copper (60,000 yuan / ton), and the density is 1.5g / cm 3 , is copper (8.93g / cm 3 ) of 17%; considering that the wall thickness of the present invention is 2.0 mm, the material cost of the present invention is that of the copper muffler: 0.33*0.17*2.0=11% (excluding metal inserts).

[0051] The technical means disclosed in the scheme of the present invention are not limited to the technical means disclosed in the above-mentioned implementation mode, but also include technical schemes composed of any combination of the above-mentioned technical features. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications are also regarded as the protection scope of the present invention.

Claims

1. An air conditioner muffler based on polymer composite material injection molding and ultrasonic welding, comprising a muffler body, the muffler body being a tubular structure with reduced apertures at both ends, characterized in that: The muffler body is divided into section A and section B, and the sections A and B are injection molded separately and welded into a whole by ultrasonic welding. The welding surfaces of the sections A and B are respectively provided with self-locking heads and self-locking grooves, and the self-locking heads and self-locking grooves are adapted to each other and tightly pressed together. A pipe sleeve structure is provided at both ends of the muffler body, and a metal pipe for welding the muffler body to the copper pipe of the peripheral refrigeration system is embedded in the pipe sleeve structure. The metal pipe is molded as a whole with the muffler body during the injection molding process, and an annular flame baffle is provided on the outside of the middle.

2. The air conditioner muffler based on polymer composite material injection molding and ultrasonic welding according to claim 1, characterized in that: The muffler body is a nylon plus 30% glass fiber polymer composite muffler.

3. The air conditioner muffler based on polymer composite material injection molding and ultrasonic welding according to claim 1, characterized in that: The self-locking head is provided with three end faces a, b and c for welding, wherein the end faces a and c are parallel to each other in annular shapes, and the outer diameter of the end face a is greater than the outer diameter of the end face c and is perpendicular to the ultrasonic injection direction, and the end face b is horn-shaped and is perpendicular to the ultrasonic injection direction. β Angle, the small aperture end is connected to the outer side of the C end face, and the self-locking groove is provided with a welding end face adapted to the self-locking head.

4. The air conditioner muffler based on polymer composite material injection molding and ultrasonic welding according to claim 3 is characterized in that: The a, b, and c end faces are continuous faces connected in sequence, and the inner side of the a end face is connected to the large-aperture end of the b end face.

5. The air conditioner muffler based on polymer composite material injection molding and ultrasonic welding according to claim 3, characterized in that: The end faces a and b are connected via a cylindrical surface.

6. The air conditioner muffler based on polymer composite material injection molding and ultrasonic welding according to claim 1, characterized in that: The metal tube is a 304 stainless steel tube, and the metal tube and the flame baffle are directly formed by metal cold forging.

7. The air conditioner muffler based on polymer composite material injection molding and ultrasonic welding according to claim 1, characterized in that: The edge of the flame baffle is folded 90° toward the muffler body.

8. The air conditioner muffler based on polymer composite material injection molding and ultrasonic welding according to claim 1, characterized in that: The metal spiral wire is integrally injection-molded in the A section and the B section to improve the elastic modulus of the muffler body.

9. The air conditioner muffler based on polymer composite material injection molding and ultrasonic welding according to claim 1, characterized in that: A filter screen for filtering refrigerant is installed between section A and section B.

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