Method for manufacturing resin silencer

Abstract

To provide a highly versatile manufacturing method applicable even if a joining part of respective divided bodies has various shapes when manufacturing a silencer by joining two divided bodies made of resin.SOLUTION: A 6A and a 8A of a split body are resin-molded in a shape in which a muffler 1 in which a pipe part 4 of a small diameter is connected to both ends in the axial direction of a cylindrical barrel part 2 through an expanded pipe part 3 crosses the axial direction or is split into two along the axial direction. The facing surfaces 7, 9 of the side 6A and the 8A of the respective divided bodies are irradiated with infrared rays from an irradiation part 11 or a heated hot plate 14 is brought close to the facing surfaces 7, 9 to melt the facing surfaces 7, 9, and the melted facing surfaces 7, 9 are brought into contact with each other and joined to integrate the side 6A and the 8A of the divided bodies.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a resin silencer that is connected to the piping of an automotive air conditioner. [Background technology]

[0002] Silencers are attached to the piping of automotive air conditioners to suppress noise caused by the flow of circulating refrigerant. In recent years, with the trend toward lighter automobiles, various studies have been conducted on replacing metal piping with plastic piping to reduce weight.

[0003] In order to manufacture a resin silencer that is lightweight yet has sufficient resistance to internal pressure, a method has been proposed in which a cylindrical insertion part (insertion part) and a cylindrical receiving part (receiving part) are integrated into a cylindrical part by spin welding (see Patent Document 1). In this proposed method, the specifications of the insertion part and the receiving part are devised to enable a stable and strong joining of the two.

[0004] However, in this method of manufacturing a silencer by joining two resin parts by spin welding, the joining portions of the resin parts are limited to a cylindrical shape, so another method is needed to make the joining portions of the two resin parts applicable to various shapes other than cylindrical. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2023-155659 Summary of the Invention [Problem to be solved by the invention]

[0006] The object of the present invention is to provide a highly versatile manufacturing method for manufacturing a resin silencer connected to the piping of an automotive air conditioner by joining two resin segments, which can be applied even when the joining parts of the segments are not limited to being cylindrical but have various shapes. [Means for solving the problem]

[0007] In order to achieve the above object, the method for manufacturing a resin silencer of the present invention is a method for manufacturing a resin silencer to be connected to the piping of an automotive air conditioner, the silencer having a cylindrical body and pipe sections connected to both axial ends of the body via expanded sections and having a smaller diameter than the body, characterized in that the silencer is molded into two divided bodies along the axial direction or along a direction transverse to the axial direction by resin molding, and the opposing surfaces of each of the divided bodies are melted by irradiating them with infrared rays or bringing a hot plate close to them, and the molten opposing surfaces are brought into contact and welded together to join the divided bodies into one unit. [Effects of the Invention]

[0008] According to the present invention, by irradiating each of the opposing surfaces with infrared rays or by bringing a hot plate close to the opposing surfaces, the opposing surfaces are melted and the molten opposing surfaces are brought into contact and welded together. Therefore, the joining portions of the divided bodies are not limited to being cylindrical, and the divided bodies can be joined and integrated even if they have other shapes. As each of the divided bodies, a divided body having a shape in which the silencer is divided into two along the axial direction, or a divided body having a shape in which the silencer is divided into two along a direction transverse to the axial direction, can be used. Therefore, this manufacturing method is highly versatile, as it can produce lightweight resin silencers of various shapes that have sufficient pressure resistance against internal pressure. [Brief explanation of the drawings]

[0009] [Figure 1]1 is an explanatory diagram illustrating a silencer manufactured according to the present invention as viewed from the front. [Figure 2] 2 is an explanatory diagram illustrating the silencer of FIG. 1 in a vertical cross-sectional view. FIG. [Figure 3] 3 is an explanatory view illustrating one divided body and the other divided body of FIG. 2 in a separated state. FIG. [Figure 4] 4 is an explanatory view illustrating the structure of one of the divided bodies in a cross section taken along the line AA in FIG. 3. FIG. [Figure 5] 4 is an explanatory view illustrating a process of irradiating infrared rays onto the opposing surfaces of one divided body and the other divided body of FIG. 3 from an irradiation unit disposed in a gap between the opposing surfaces. FIG. [Figure 6] 6 is an explanatory diagram illustrating a state in which the irradiation unit in FIG. 5 is moved outward from the gap between the opposing surfaces. FIG. [Figure 7] 7 is an explanatory view illustrating a process of welding and joining one divided body and the other divided body of FIG. 6 by bringing their opposing surfaces into contact with each other. FIG. [Figure 8] 6A to 6C are explanatory views showing modified examples of the opposing surfaces of FIG. 5. [Figure 9] 9 is an explanatory view illustrating a process of welding and joining one divided body and the other divided body of FIG. 8 by bringing their opposing surfaces into contact with each other. [Figure 10] 10 is an explanatory diagram showing a modified example of a reinforcing rib in a front view of the silencer. FIG. [Figure 11] 10 is an explanatory diagram showing another modified example of the reinforcing rib in a front view of the silencer. FIG. [Figure 12] 10 is an explanatory diagram illustrating another embodiment of the silencer as viewed from the front. FIG. [Figure 13] 13 is an explanatory diagram illustrating one divided body and the other divided body of FIG. 12 in a separated state in a vertical cross section. FIG. [Figure 14] 14 is an explanatory view illustrating a process of irradiating the opposing surfaces of one divided body and the other divided body of FIG. 13 with infrared rays from an irradiation unit disposed in a gap between the opposing surfaces. FIG. [Figure 15] 15 is an explanatory view illustrating a process of welding and joining the opposing surfaces of one divided body and the other divided body by bringing the opposing surfaces into contact with each other after the irradiation unit in FIG. 14 is moved outward from the gap between the opposing surfaces. FIG. [Figure 16] 14A to 14C are explanatory views showing modified examples of the opposing surfaces of FIG. 13. [Figure 17] 17 is an explanatory view illustrating a process of welding and joining the opposing surfaces of one divided body and the other divided body of FIG. 16 together. FIG. [Figure 18] 10 is an explanatory diagram illustrating another embodiment of the silencer as viewed from the front. FIG. [Figure 19] 19 is an explanatory diagram illustrating the silencer of FIG. 18 in a vertical cross-sectional view. FIG. [Figure 20] 19 is an explanatory diagram illustrating the silencer of FIG. 18 in cross section. FIG. [Figure 21] 20 is an explanatory view illustrating one divided body and the other divided body of FIG. 19 in a separated state. FIG. [Figure 22] 21 is an explanatory view illustrating one divided body and the other divided body of FIG. 20 in a separated state. FIG. [Figure 23] 23 is an explanatory view illustrating a process of irradiating the opposing surfaces of one divided body and the other divided body of FIG. 22 with infrared rays from an irradiation unit disposed in a gap between the opposing surfaces. FIG. [Figure 24] 24 is an explanatory diagram illustrating a state in which the irradiating unit in FIG. 23 is moved outward from the gap between the opposing surfaces. FIG. [Figure 25] 25 is an explanatory view illustrating a process of welding and joining the opposing surfaces of one divided body and the other divided body of FIG. 24 by abutting them against each other. FIG. [Figure 26] 23 is an explanatory diagram showing a modified example of each of the opposing surfaces in FIG. 22. FIG. [Figure 27] 27 is an explanatory view illustrating a process of irradiating the opposing surfaces of one divided body and the other divided body of FIG. 26 with infrared rays and then bringing the opposing surfaces into contact with each other to weld and join them. FIG. [Figure 28] FIG. 10 is an explanatory diagram illustrating a process of heating the opposing surfaces of one divided body and the other divided body constituting another form of silencer by a heat plate disposed in the gap between the opposing surfaces. [Figure 29] FIG. 10 is an explanatory diagram illustrating a process of heating the opposing surfaces of one divided body and the other divided body constituting yet another form of silencer by a heat plate disposed in the gap between the opposing surfaces. [Figure 30] FIG. 10 is an explanatory diagram illustrating a process of heating the opposing surfaces of one divided body and the other divided body constituting yet another form of silencer by a heat plate disposed in the gap between the opposing surfaces. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a method for manufacturing a resin silencer according to the present invention will be described based on an embodiment shown in the drawings.

[0011] According to the present invention, a resin silencer 1 as shown in FIGS. 1 and 2 is manufactured. This silencer 1 has a cylindrical body 2, and pipe sections 4 each having a smaller diameter than the body 2 are connected to both axial ends of the body 2 via expanded sections 3. Each pipe section 4 is connected to the piping of an automotive air conditioner. A refrigerant C used in the air conditioner circulates inside the hollow silencer 1. The refrigerant C flows in from one pipe section 4 and out from the other pipe section 4. The dashed-dotted line CL in the figures indicates the axis of the silencer 1, which passes through the center of the cross section of the body 2, expanded section 3, and pipe section 4. The direction in which the axis center CL extends is the axial direction.

[0012] The silencer 1 is manufactured by joining together two resin divided bodies 6A and 8A, as shown in FIG. 3. While FIG. 4 shows one divided body 6A as an example, the other divided body 8A has a similar shape. Each divided body 6A and 8A is basically made of the same resin. Various known moldable resins are used as this resin. For example, nylon resin (such as 66 nylon), polypropylene, ABS resin, etc. are used.

[0013] For reinforcement, short fibers (such as glass fibers or carbon fibers) can be mixed into the resin at a predetermined ratio (for example, 30% to 40% by mass per 100 parts by mass of the resin). The size of the short fibers is, for example, an outer diameter of about 0.001 mm to 1.0 mm and a length of about 0.01 mm to 10 mm.

[0014] Each divided body 6A, 8A has a shape in which the silencer 1 is divided into two parts transversely to the axial direction, and is manufactured by resin molding. In this embodiment, each divided body 6A, 8A has a shape in which the silencer 1 is divided into two parts along a direction perpendicular to the axial direction (at an angle of 90°). The peripheral walls of the respective opposing surfaces 7, 9 are butted together in a non-overlapping manner in the wall thickness direction (the left-right direction in Figures 2 and 3) over the entire circumferential length. Each divided body 6A, 8A has a body portion 2, an expanded tube portion 3, and a pipe portion 4 that are divided into two parts in the axial direction, and they have substantially the same shape.

[0015] The inner diameter of the body portion 2 is, for example, about 30 mm to 60 mm. The inner diameter of the pipe portion 4 is, for example, about 10 mm to 20 mm. The thickness of the peripheral walls of the body portion 2, the expanded tube portion 3, and the pipe portion 4 are approximately the same, for example, about 2 mm to 5 mm.

[0016] The opposing surfaces 7, 9 are welded together, and the boundary between the opposing surfaces 7, 9 is unclear in the manufactured silencer 1. In the drawings, the boundary between the opposing surfaces 7, 9 is shown by a dashed line for convenience. In this embodiment, the inner diameter of each opposing surface 7, 9 is the same as the inner diameter of the surrounding body portion 2 (the inner diameter of the portion where the circumferential rib 5b described later does not exist), but the outer diameter is larger than the outer diameter of the surrounding body portion 2 (the outer diameter of the portion where the circumferential rib 5a described later does not exist), and protrudes outward. Therefore, the joint portion between the segments 6A, 8A (the portion corresponding to the opposing surfaces 7, 9) functions as a circumferential rib. The inner and outer diameters of each opposing surface 7, 9 can also be made the same as those of the surrounding body portion 2 (the portion where the circumferential rib 5a, 5b does not exist).

[0017] The expanded tube section 3 is a tubular body (a cylindrical body in this embodiment) whose diameter expands from the cylindrical pipe section 4 toward the body section 2. The body section 2 is not limited to a cylindrical shape, and can have, for example, an elliptical cylindrical shape or a polygonal cylindrical shape, and therefore the expanded tube section 3 becomes a tubular body that changes from the small-diameter pipe section 4 to the shape of the large-diameter body section 2.

[0018] The inclination angle of the peripheral wall of the expanded tube section 3 relative to the axis CL is, for example, approximately 30° to 60°. The boundary between the expanded tube section 3 and the body section 2 is a convex arc, and the arc radius (R1 dimension) of the outer surface of this boundary is, for example, approximately 10 mm to 20 mm. The arc radius (R2 dimension) of the inner surface of this boundary is set so that the thickness (thickness between the outer and inner surfaces) is constant. The boundary between the expanded tube section 3 and the pipe section 4 is a concave arc, and the arc radius (R3 dimension) of the outer surface of this boundary is, for example, approximately 10 mm to 20 mm. The arc radius (R4 dimension) of the inner surface of this boundary is set so that the thickness (thickness between the outer and inner surfaces) is constant. Therefore, the cylindrical body section 2 and the cylindrical pipe section 4 are smoothly connected by the expanded tube section 3, whose inner and outer diameters gradually change.

[0019] Circumferential ribs 5a are provided on the outer peripheral surface of the body 2 so as to reinforce the body 2 and extend continuously in the circumferential direction. In this embodiment, the multiple circumferential ribs 5a are arranged at intervals in the axial direction. The circumferential ribs 5a are preferably arranged at equal intervals in the axial direction. The circumferential ribs 5a are arranged at least in the axial center of the body 2.

[0020] The protruding height of the circumferential ribs 5a (the amount of protrusion radially outward from the outer circumferential surface of the body 2) is, for example, about 2 mm to 5 mm, and the rib width is, for example, about 1 mm to 5 mm. The number and dimensions of the circumferential ribs 5a are determined appropriately based on the pressure resistance required of the silencer 1, etc.

[0021] In this embodiment, circumferential ribs 5b are provided on the inner peripheral surface of the body 2 so as to extend continuously in the circumferential direction. The main purpose of these circumferential ribs 5b is to improve the sound deadening effect, but they also have the effect of reinforcing the body 2. In this embodiment, multiple circumferential ribs 5b are arranged at intervals in the axial direction. It is preferable that the circumferential ribs 5b are arranged at equal intervals in the axial direction. The circumferential ribs 5b can be provided as desired.

[0022] The protruding height of the circumferential ribs 5b (the amount of protrusion radially inward from the inner circumferential surface of the body 2) is, for example, about 2 mm to 5 mm, and the rib width is, for example, about 1 mm to 5 mm. The number and dimensions of the circumferential ribs 5b are determined appropriately based on the sound-deadening properties required of the silencer 1, etc.

[0023] The cross-sectional shape of the circumferential ribs 5a, 5b is not limited to a semicircular shape or other shape with an arc-shaped apex, but may be a triangular shape, a square shape, or other polygonal shape, etc. Having an arc-shaped apex is advantageous in improving the durability of the circumferential ribs 5a, 5b.

[0024] As in this embodiment, the circumferential ribs 5a and 5b are preferably arranged to be offset in the axial direction. That is, the circumferential ribs 5a and 5b should be arranged so that they do not overlap in the axial direction. If the circumferential ribs 5a and 5b were arranged so that they overlap in the axial direction, the amount of resin in the body portion 2 would be excessively unevenly distributed, which would be disadvantageous for successful injection molding of the segments 6A and 8A.

[0025] An example of a procedure for manufacturing this silencer 1 will now be described.

[0026] First, the segments 6A and 8A shown in Fig. 3 are manufactured by a known resin molding method. For example, the segments 6A and 8A may be injection molded using a known injection molding machine. When the segments 6A and 8A are injection molded, the circumferential ribs 5a and 5b are also molded integrally at the same time.

[0027] Next, as illustrated in FIGS. 5 to 7, the divided bodies 6A and 8A are joined together and integrated using an infrared welding device 10. More specifically, various known types of infrared welding device 10 can be used, and the device has an irradiation unit 11 that irradiates infrared rays and holding units 12a and 12b that move toward and away from each other. At least one of the holding units 12a and 12b must be able to move toward and away from the other unit. As illustrated in FIG. 5, the divided bodies 6A and 8A are held by the holding units 12a and 12b, with the opposing surfaces 7 and 9 facing each other but spaced apart. In this state, the irradiation unit 11 is inserted into the gap between the opposing surfaces 7 and 9, and the irradiation unit 11 is positioned out of contact with the opposing surfaces 7 and 9.

[0028] The distance (axial distance) between the irradiating unit 11 and the opposing surface 7 and the distance (axial distance) between the irradiating unit 11 and the opposing surface 9 are made substantially the same over the entire surface. The irradiating unit 11, which is disposed in the gap between the opposing surfaces 7, 9, irradiates each of the opposing surfaces 7, 9 with infrared rays for a predetermined period of time. As a result, the resin on the entire surfaces of the opposing surfaces 7, 9 is melted by the irradiated infrared rays.

[0029] Next, as shown in Fig. 6, the irradiation unit 11 is moved outside the respective divided bodies 6A, 8A (in a direction perpendicular to the axial direction), so that the molten opposing surfaces 7, 9 face each other with a gap therebetween.

[0030] Next, as shown in Fig. 7, one retaining portion 12a is moved axially and brought close to the other retaining portion 12b, which is fixed in a predetermined position, so that the molten opposing surfaces 7, 9 come into contact with each other without any gaps. The other retaining portion 12b may be moved axially toward the one retaining portion 12a, which is fixed in a predetermined position. Thereafter, the retaining portions 12a, 12b are maintained at a predetermined distance from each other, and the molten resin on the opposing surfaces 7, 9 is cooled and hardened, thereby welding the opposing surfaces 7, 9 to each other. In this way, the respective divided bodies 6A, 8A are joined and integrated to manufacture the silencer 1.

[0031] The process from melting the opposing surfaces 7, 9 to bringing them into contact with each other must be carried out quickly, for example, within 1 to 10 seconds. The optimum ranges for the output of the infrared rays to be irradiated, the irradiation time, the distance between the irradiation unit 11 and each of the opposing surfaces 7, 9, and the pressure to be applied to the opposing surfaces 7, 9 vary slightly depending on the specifications of the segments 6A, 8A. Therefore, preliminary tests are conducted to determine these optimum ranges, and the opposing surfaces 7, 9 are welded together using the determined optimum ranges.

[0032] In this embodiment, each of the divided bodies 6A, 8A has a shape in which the silencer 1 is divided into two along a direction perpendicular to the axial direction, so the joint area between the divided bodies 6A, 8A (the area of ​​the opposing surfaces 7, 9) is minimized. This is advantageous for more uniformly joining the opposing surfaces 7, 9. If there is variation in the joint strength of the joints, damage will be concentrated in areas with low joint strength, so being able to more uniformly join the opposing surfaces 7, 9 greatly contributes to improving durability.

[0033] The opposing surfaces 7, 9 protrude more radially outward than the surrounding body portion 2, increasing the bonding area between them. The engagement portions 7a, 9a also increase the bonding area between the opposing surfaces 7, 9. This is advantageous for improving the bonding strength between the segments 6A, 8A.

[0034] In this silencer 1, the body portion 2 and the pipe portion 4 are connected via the expanded portion 3, so that when internal pressure acts during use of the silencer 1, it is possible to prevent excessive stress from occurring locally in the region between the body portion 2 and the pipe portion 4. The circumferential rib 5a resists the internal pressure acting on the silencer 1, so it is possible to prevent excessive stress from occurring locally. Therefore, with this silencer 1, it is possible to ensure sufficient pressure resistance against internal pressure even though it is made of lightweight resin.

[0035] As shown in Fig. 2, in the piping system of an automotive air conditioner, refrigerant C flows into one pipe section 4, passes through expanded section 3, body section 2, and expanded section 3, and flows out of the other pipe section 4, repeatedly circulating. In expanded section 3, refrigerant C flows along the inner circumferential surface. In this embodiment, the circulating refrigerant C is interfered with by circumferential ribs 5b protruding from the inner circumferential surface of body section 2, thereby canceling out the noise and pulsation caused by the circulating refrigerant C, thereby further reducing the noise and pulsation.

[0036] The circumferential ribs 5b may be arranged in the axial direction with different protruding heights. The circumferential ribs 5b are not limited to the protruding direction perpendicular to the axial direction as in the above-described embodiment, but may be protruding at an angle toward the other axial side (the other pipe portion 4 side from which the refrigerant C flows out).

[0037] As shown in Fig. 8, it is also possible to use divided bodies 6A, 8A that are divided into two so that the peripheral walls of the opposing surfaces 7, 9 of each body overlap in the wall thickness direction (left and right direction in Fig. 8) over the entire circumferential length. The divided bodies 6A, 8A in Fig. 8 differ from the divided bodies 6A, 8A in Fig. 3 only in the specifications of the opposing surfaces 7, 9, and the other specifications are the same.

[0038] The procedure for manufacturing the silencer 1 using these divided bodies 6A, 8A is substantially the same as the procedure for manufacturing the silencer 1 illustrated in Figures 1 and 2. First, the divided bodies 6A, 8A illustrated in Figure 8 are manufactured by resin injection molding. Next, the irradiation unit 11 is placed in the gap between the opposing surfaces 7, 9, which are spaced apart from each other, without contacting the opposing surfaces 7, 9. In order to keep the distance between the irradiation unit 11 and the opposing surfaces 7, 9 constant over the entire circumferential length, the shape of the irradiation unit 11 is made to match the shape of the opposing surfaces 7, 9.

[0039] The opposing surfaces 7 and 9 are melted by the infrared rays irradiated from the irradiation unit 11. Next, as shown in Fig. 9, the molten opposing surfaces 7 and 9 are brought into contact with each other and welded together. This joins and integrates the divided bodies 6A and 8A.

[0040] 9, the peripheral walls of the opposing surfaces 7, 9 overlap in the wall thickness direction over the entire circumferential length, so that one opposing surface 7 is convex and the other opposing surface 9 is concave, and they fit together in the axial direction. This is advantageous for crimping while suppressing misalignment of the divided bodies 6A, 8A (opposing surfaces 7, 9).

[0041] The peripheral wall of the other opposing surface 9 covers the outer periphery of the peripheral wall of one opposing surface 7 over the entire circumferential length. Therefore, the joining area between the opposing surfaces 7, 9 is increased compared to when the peripheral walls of the opposing surfaces 7, 9 are butted together over the entire circumferential length with no overlap in the wall thickness direction. This is advantageous for improving the joining strength between the segments 6A, 8A.

[0042] 10, in addition to the circumferential ribs 5a, axial ribs 5c extending in the axial direction can also be provided protrudingly on the outer peripheral surface of the body portion 2. The axial ribs 5c are molded integrally with the divided bodies 6A and 8A at the same time when the divided bodies 6A and 8A are injection molded.

[0043] The axial ribs 5c are preferably arranged at least in the axial center of the body portion 2, in the range where the circumferential ribs 5a are arranged. The protruding height and rib width of the axial ribs 5c are the same as those of the circumferential ribs 5a. Three or more axial ribs 5c are arranged at equal intervals around the circumferential direction of the body portion 2, and preferably, for example, three to twelve axial ribs. By providing the axial ribs 5c in addition to the circumferential ribs 5a, it is advantageous to further improve the durability of the body portion 2 (silencer 1).

[0044] Instead of the axial ribs 5c shown in Fig. 10, as shown in Fig. 11, diagonal ribs 5d may be provided on the outer peripheral surface of the body 2, extending at an angle of, for example, 30° to 60° relative to the axial direction. The diagonal ribs 5d are molded integrally with the segments 6A and 8A simultaneously when they are injection molded. The protruding height and width of the diagonal ribs 5d are set to be the same as those of the circumferential ribs 5a.

[0045] The silencer 1 of the embodiment shown in Fig. 12 is manufactured by joining and integrating two divided bodies 6A, 8A shown in Fig. 13. Each divided body 6A, 8A has a shape in which the silencer 1 is divided into two bodies transversely in the axial direction. More specifically, each divided body 6A, 8A has a shape in which the silencer 1 is divided into two bodies along a direction in which the silencer 1 is uniformly inclined with respect to the axial direction (at an inclination angle B of about 80°). This inclination angle B can be set, for example, in the range of 60° or more and less than 90°.

[0046] The silencer 1 shown in FIG. 12 does not have a shape in which each of the divided bodies 6A, 8A is divided into two along a direction perpendicular to the axial direction. This silencer 1 does not have a circumferential rib 5b, but it can also be configured to have a circumferential rib 5b. In other words, this silencer 1 differs from the silencer 1 shown in FIGS. 1 and 2 in the specifications of the opposing surfaces 7, 9. The other specifications of this silencer 1 are substantially the same as those of the silencer 1 shown in FIGS. 1 and 2. The various arrangements described for the silencer 1 shown in FIGS. 1 and 2 can also be applied to this silencer 1.

[0047] The procedure for manufacturing this silencer 1 is substantially the same as the procedure for manufacturing the silencer 1 illustrated in Figures 1 and 2. First, the divided bodies 6A and 8A illustrated in Figure 13 are manufactured by resin injection molding. Next, as illustrated in Figure 14, an irradiation unit 11 is placed in the gap between the opposing surfaces 7 and 9 while not in contact with the opposing surfaces 7 and 9, and the opposing surfaces 7 and 9 are melted by infrared rays irradiated from the irradiation unit 11.

[0048] Next, each of the divided bodies 6A, 8A is moved in the axial direction, and then the opposing surfaces 7, 9 are brought into contact with each other as shown in Fig. 15. As a result, the molten opposing surfaces 7, 9 are welded together, and the divided bodies 6A, 8A are joined and integrated to produce the silencer 1.

[0049] 14, the peripheral walls of the opposing surfaces 7, 9 overlap in the wall thickness direction, but in other cross-sectional views, the peripheral walls of the opposing surfaces 7, 9 are butted together but not overlapped in the wall thickness direction. In other words, the peripheral walls of the opposing surfaces 7, 9 do not overlap in the wall thickness direction over the entire circumferential length.

[0050] In this embodiment, the opposing surfaces 7, 9 extend in a direction that is uniformly inclined and transverse to the axial direction, which increases the area of ​​the opposing surfaces 7, 9 compared to the specification in which the opposing surfaces 7, 9 extend in a direction perpendicular to the axial direction as shown in Figure 1. This increases the bonding area between the opposing surfaces 7, 9, which is advantageous for improving the bonding strength between the segments 6A, 8A.

[0051] As shown in Fig. 16, it is also possible to use divided bodies 6A, 8A that are divided into two so that the peripheral walls of the opposing surfaces 7, 9 of each body overlap in the wall thickness direction (left and right direction in Fig. 16) over the entire circumferential length. The divided bodies 6A, 8A in Fig. 16 differ from the divided bodies 6A, 8A in Fig. 14 only in the specifications of the opposing surfaces 7, 9, and the other specifications are the same.

[0052] The procedure for manufacturing this silencer 1 is substantially the same as the procedure for manufacturing the silencer 1 illustrated in Fig. 7. First, the divided bodies 6A and 8A illustrated in Fig. 16 are manufactured by resin injection molding. Next, the irradiation unit 11 is placed in the gap between the opposing surfaces 7 and 9, which are spaced apart from each other, without contacting the opposing surfaces 7 and 9. In order to keep the distance between the irradiation unit 11 and the opposing surfaces 7 and 9 constant over the entire circumferential length, the shape of the irradiation unit 11 is made to match the opposing surfaces 7 and 9. The opposing surfaces 7 and 9 are melted by the infrared rays irradiated from this irradiation unit 11.

[0053] 17, the divided bodies 6A, 8A are then moved axially to bring the opposing surfaces 7, 9 into contact with each other. This causes the molten opposing surfaces 7, 9 to be welded together, joining and integrating the divided bodies 6A, 8A, and producing the silencer 1.

[0054] 17, the peripheral walls of the opposing surfaces 7, 9 overlap in the wall thickness direction over the entire circumferential length, so that one opposing surface 7 is concave and the other opposing surface 9 is convex, and they fit together in the axial direction. This is advantageous for crimping while suppressing misalignment of the divided bodies 6A, 8A (opposing surfaces 7, 9).

[0055] The peripheral wall of one opposing surface 7 covers the outer periphery of the peripheral wall of the other opposing surface 9 over the entire circumferential length. This increases the bonding area between the opposing surfaces 7, 9 compared to when the peripheral walls of the opposing surfaces 7, 9 are butted together without overlapping in the wall thickness direction over the entire circumferential length. This is advantageous for improving the bonding strength between the segments 6A, 8A.

[0056] The silencer 1 of the embodiment illustrated in Figures 18 to 20 is manufactured by joining and integrating two divided bodies 6B, 8B illustrated in Figures 21 and 22. Each divided body 6B, 8B has a shape in which the silencer 1 is divided into two along the axial direction. In addition, the peripheral walls of the respective opposing surfaces 7, 9 are butted together in a non-overlapping state in the wall thickness direction over the entire axial length.

[0057] That is, this silencer 1 differs from the silencer 1 illustrated in FIGS. 1 and 2 in the specifications of the opposing surfaces 7, 9 (the division direction of the segments 6B, 8B). The segments 6B, 8B do not have circumferential ribs 5b, but they can also be designed to have circumferential ribs 5b. The other specifications of this silencer 1 are substantially the same as those of the silencer 1 illustrated in FIGS. 1 and 2. The various arrangements described for the silencer 1 illustrated in FIGS. 1 and 2 can also be applied to this silencer 1.

[0058] The procedure for manufacturing this silencer 1 is substantially the same as the procedure for manufacturing the silencer 1 illustrated in Figures 1 and 2. First, the divided bodies 6B and 8B illustrated in Figures 21 and 22 are manufactured by resin injection molding. Next, as illustrated in Figure 23, an irradiation unit 11 is placed in the gap between the opposing surfaces 7 and 9 while not in contact with the opposing surfaces 7 and 9, and the opposing surfaces 7 and 9 are melted by infrared rays irradiated from the irradiation unit 11.

[0059] 24, after the opposing surfaces 7 and 9 are melted, the irradiation unit 11 is moved to the outside of the divided bodies 6A and 8A (in a direction perpendicular to the axial direction), so that the melted opposing surfaces 7 and 9 face each other with a gap therebetween.

[0060] 25, each of the divided bodies 6A, 8A is moved in a direction perpendicular to the axial direction so that the opposing surfaces 7, 9 come into contact with each other, and the molten opposing surfaces 7, 9 are welded together. At least one of the divided bodies 6A, 8A is moved toward the other to bring the opposing surfaces 7, 9 into contact with each other.

[0061] In this embodiment, the opposing surfaces 7, 9 extend along the axial direction, which increases the area of ​​the opposing surfaces 7, 9 compared to specifications in which the opposing surfaces 7, 9 extend along a direction transverse to the axial direction. This increases the bonding area between the opposing surfaces 7, 9, which is advantageous for improving the bonding strength between the segments 6B, 8B.

[0062] As shown in Fig. 26, it is also possible to use divided bodies 6A, 8A that are divided into two so that the peripheral walls of the opposing surfaces 7, 9 of each body overlap in the wall thickness direction over the entire axial length. The divided bodies 6A, 8A of Fig. 26 differ from the divided bodies 6A, 8A of Fig. 22 only in the specifications of the opposing surfaces 7, 9, and the other specifications are the same.

[0063] The procedure for manufacturing this silencer 1 is substantially the same as the procedure for manufacturing the silencer 1 illustrated in Fig. 20. First, the divided bodies 6B and 8B illustrated in Fig. 26 are manufactured by resin injection molding. Next, the irradiation unit 11 is placed in the gap between the opposing surfaces 7 and 9, which are spaced apart and facing each other, without contacting the opposing surfaces 7 and 9. In order to keep the distance between the irradiation unit 11 and the opposing surfaces 7 and 9 constant over the entire axial length, the shape of the irradiation unit 11 is made to fit the opposing surfaces 7 and 9. The opposing surfaces 7 and 9 are melted by the infrared rays irradiated from this irradiation unit 11.

[0064] Next, the irradiation unit 11 is moved outside each of the segments 6B and 8B (in a direction perpendicular to the axial direction). This causes the molten opposing surfaces 7 and 9 to face each other with a gap between them. Next, as shown in FIG. 27, each of the segments 6B and 8B is moved in a direction perpendicular to the axial direction to bring the opposing surfaces 7 and 9 into contact with each other, thereby welding the molten opposing surfaces 7 and 9 together. At least one of the segments 6B and 8B is moved toward the other to bring the opposing surfaces 7 and 9 into contact with each other.

[0065] 27, the peripheral walls of the opposing surfaces 7, 9 overlap in the wall thickness direction over the entire axial length, so that one opposing surface 7 is convex and the other opposing surface 9 is concave, and they fit together in the circumferential direction. This is advantageous for crimping while suppressing misalignment of the divided bodies 6A, 8A (opposing surfaces 7, 9).

[0066] The peripheral wall of the other opposing surface 9 covers the outer periphery of the peripheral wall of one opposing surface 7 over the entire axial length. This increases the area of ​​the opposing surfaces 7, 9 compared to when the peripheral walls of the opposing surfaces 7, 9 are butted together without overlapping in the wall thickness direction over the entire axial length. This increases the bonding area between the opposing surfaces 7, 9, which is advantageous for improving the bonding strength between the segments 6B, 8B.

[0067] In the various embodiments for manufacturing the silencer 1 described above, the opposing surfaces 7, 9 are welded together using infrared rays, but the opposing surfaces 7, 9 can also be welded together by using heating with a hot plate 14 instead of infrared rays. Therefore, a method for manufacturing the silencer 1 using a hot plate welding device 13 will be described below.

[0068] 1 and 2, as shown in Fig. 28, a hot plate 14 is brought close to the opposing surfaces 7, 9 to melt the opposing surfaces 7, 9, and the molten opposing surfaces 7, 9 are brought into contact with each other and welded together. In this way, the divided bodies 6A, 8A are joined together and integrated to manufacture the silencer 1.

[0069] The hot plate welding device 13 can be of various known types and includes a hot plate 14 heated to a predetermined temperature and holders 15a and 15b that move toward and away from each other. At least one of the holders 15a and 15b must be able to move toward and away from the other. The divided bodies 6A and 8A are held by the holders 15a and 15b, with the opposing surfaces 7 and 9 facing each other but spaced apart. In this state, the hot plate 14 is inserted into the gap between the opposing surfaces 7 and 9, and is positioned without contacting the opposing surfaces 7 and 9.

[0070] The distance (axial distance) between the hot plate 14 and the opposing surface 7 and the distance (axial distance) between the hot plate 14 and the opposing surface 9 are substantially the same over the entire surface. The hot plate 14 disposed in the gap between the opposing surfaces 7 and 9 heats each of the opposing surfaces 7 and 9 for a predetermined time. This heating melts the resin on the entire surfaces of the opposing surfaces 7 and 9.

[0071] Next, the hot plate 14 is moved to the outside of each of the divided bodies 6A and 8A (in a direction perpendicular to the axial direction), whereby the molten opposing surfaces 7 and 9 are placed opposite each other with a gap therebetween.

[0072] Next, one of the retaining portions 15a is moved axially toward the other retaining portion 15b, which is fixed in a predetermined position, so that the molten opposing surfaces 7 and 9 are brought into contact with each other without any gaps. The other retaining portion 15b may be moved axially toward the one retaining portion 15a, which is fixed in a predetermined position. Thereafter, the retaining portions 15a and 15b are maintained at a predetermined distance from each other, and the molten resin on the opposing surfaces 7 and 9 is cooled and hardened, thereby welding the opposing surfaces 7 and 9 together. This joins and integrates the respective segments 6A and 8A to produce the silencer 1. That is, when using the hot plate welding device 13, the only difference is that the irradiation portion 11 used in the infrared welding device 10 is replaced with a hot plate 14; otherwise, the procedure is essentially the same.

[0073] The process from melting the opposing surfaces 7, 9 to bringing them into contact with each other must be performed quickly, for example, within 1 to 10 seconds. Furthermore, the manufacturing process can be shortened by preheating the hot plate 14 to a predetermined temperature before inserting it into the gap between the opposing surfaces 7, 9. The optimal ranges for the heating temperature and heating time of the hot plate 14, the distance between the hot plate 14 and the opposing surfaces 7, 9, and the pressure applied to the opposing surfaces 7, 9 vary slightly depending on the specifications of the segments 6A, 8A. Therefore, preliminary tests should be conducted to determine these optimal ranges, and the opposing surfaces 7, 9 can be welded together using the determined optimal ranges.

[0074] To manufacture the silencer 1 shown in FIG. 12, in which the opposing surfaces 7 and 9 extend in a direction uniformly inclined relative to the axial direction, a hot plate 14 is brought close to each of the opposing surfaces 7 and 9, as shown in FIG. 29, to melt the opposing surfaces 7 and 9. To keep the distance between the hot plate 14 and the opposing surfaces 7 and 9 constant over the entire circumferential length, the hot plate 14 is shaped to conform to the opposing surfaces 7 and 9. Next, the hot plate 14 is moved outside the divided bodies 6A and 8A (in a direction perpendicular to the axial direction) so that the molten opposing surfaces 7 and 9 face each other with a gap between them. Next, at least one of the holding portions 15a and 15b is brought close to the other side, causing the molten opposing surfaces 7 and 9 to abut against each other and be welded.

[0075] 18 to 20, in which the opposing surfaces 7, 9 extend along the axial direction, is manufactured by bringing a hot plate 14 close to each of the opposing surfaces 7, 9, as shown in FIG. 30, to melt the opposing surfaces 7, 9. Next, the hot plate 14 is moved outside each of the divided bodies 6B, 8B (in a direction perpendicular to the axial direction) to bring the molten opposing surfaces 7, 9 into opposition with a gap between them. Next, at least one of the holding portions 15a, 15b is brought close to the other side, so that the molten opposing surfaces 7, 9 come into contact with each other and are welded.

[0076] When the silencer 1 is manufactured using the hot plate welding device 13, the various arrangements described in the case where the infrared wave welding device 10 is used can also be applied.

[0077] As in the various embodiments of the silencer 1 described above, the opposing surfaces 7, 9 are melted by irradiating them with infrared rays or bringing a hot plate close to them, and the molten opposing surfaces 7, 9 are then brought into contact and welded together, so the joining portions of the divided bodies 6A (6B), 8A (8B) are not limited to being cylindrical, and even if they have other shapes, the divided bodies 6A (6B), 8A (8B) can be joined together and integrated. Therefore, this manufacturing method is highly versatile, as it can manufacture silencers 1 of various shapes made of resin that are lightweight and have sufficient pressure resistance against internal pressure.

[0078] The method of welding and joining the opposing surfaces 7, 9 together using the infrared welding device 10 allows the opposing surfaces 7, 9 to be welded together in a shorter time, which is advantageous for reducing power consumption. On the other hand, the hot plate welding device 13 has the advantage of being simpler in configuration and not generating noise. [Explanation of symbols]

[0079] 1 silencer 2. Torso 3 Expanded section 4 Pipe section 5a, 5b Circumferential rib 5c Axial rib 5d diagonal rib 6A, 6B One of the divisions 7 Opposite Surface 8A, 8B Other divided body 9 Opposite Surface 10 Infrared welding equipment 11 Irradiation unit 12a, 12b holding part 13 Hot plate welding equipment 14 Hot plate 15a, 15b holding part C Refrigerant

Claims

1. A method for manufacturing a resin silencer to be connected to piping of an automotive air conditioner, the silencer having a cylindrical body portion and pipe portions connected to both axial ends of the body portion via expanded pipe portions and having a smaller diameter than the body portion, The silencer is molded by resin molding into a divided body having a shape divided into two parts across the axial direction or along the axial direction, A method for manufacturing a resin silencer in which the opposing surfaces of each of the divided bodies are melted by irradiating them with infrared rays or bringing a hot plate close to them, and the molten opposing surfaces are brought into contact and welded together to join and integrate the divided bodies.

2. 2. The method for manufacturing a resin silencer according to claim 1, wherein each of the divided bodies is formed by dividing the silencer into two bodies along a direction perpendicular to the axial direction.

3. 2. The method for manufacturing a resin silencer according to claim 1, wherein each of the divided bodies is formed by dividing the silencer into two bodies along a direction that is uniformly inclined relative to the axial direction.

4. 2. The method for manufacturing a resin silencer according to claim 1, wherein each of the divided bodies is a divided body in which the silencer is divided into two along the axial direction.

5. 4. A method for manufacturing a resin silencer according to claim 2 or 3, wherein each divided body is a divided body shaped so that the peripheral walls of each of the opposing surfaces are butted together in a non-overlapping manner in the wall thickness direction over the entire circumferential length.

6. 4. A method for manufacturing a resin silencer according to claim 2 or 3, wherein each divided body is a divided body having a shape in which the peripheral walls of the opposing surfaces are divided into two so as to overlap in the wall thickness direction over the entire circumferential length.

7. 5. A method for manufacturing a resin silencer as described in claim 4, wherein each divided body is a divided body shaped so that the peripheral walls of each opposing surface are butted together in a non-overlapping manner in the wall thickness direction over the entire axial length.

8. 5. A method for manufacturing a resin silencer as described in claim 4, wherein each divided body is a divided body that is divided into two so that the peripheral walls of each opposing surface overlap in the wall thickness direction over the entire axial length.

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