Method for producing resin silencer

Abstract

For provision of a silencer by joining two divided bodies made of a resin, a highly versatile manufacturing method is provided that can be applied even when joint portions of the respective divided bodies have various shapes. A silencer 1 in which small-diameter pipe parts 4 are connected to both axial end parts of a cylindrical barrel part 2 via expanded pipe parts 3 crosses in the axial direction. Divided bodies 6A, 8A, which are parts divided in two along the axial direction, are molded by resin molding, facing surfaces 7, 9 of the respective divided bodies 6A, 8A are melted by irradiating the facing surfaces 7,9 with infrared rays from an irradiation part 11, or bringing a heated hot plate 14 close to the respective facing surfaces 7, 9, and the divided bodies 6A and 8A are integrated by bringing the molten facing surfaces 7 and 9 into contact with each other and joining them.

Description

Manufacturing method for resin silencer

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

[0002] Silencers are connected 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 methods have been studied for 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.

[0005] Japanese Patent Application Publication No. 2023-155659

[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 portions of the segments are not limited to being cylindrical but have various shapes.

[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 formed by molding a split body into two parts along the axial direction or along a direction transverse to the axial direction using resin molding, and the opposing surfaces of each of the split 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 split bodies into a single unit.

[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 surfaces are brought into contact with each other to be welded. Therefore, the joining portions of the segments are not limited to being cylindrical, and segments having other shapes can be joined and integrated together. As each segment, a segment in which the silencer is divided into two along the axial direction can be used, or a segment 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 internal pressure resistance.

[0009] FIG. 1 is an explanatory diagram illustrating a silencer manufactured according to the present invention, as seen from the front. FIG. 2 is an explanatory diagram illustrating the silencer of FIG. 1, as seen in vertical cross section. FIG. 3 is an explanatory diagram illustrating one of the segments of FIG. 2 in a separated state. FIG. 4 is an explanatory diagram illustrating the structure of one of the segments, taken along the line A-A in FIG. 3. FIG. 5 is an explanatory diagram illustrating a process of irradiating infrared rays onto the opposing surfaces of one of the segments and the other of the segments of FIG. 3 from an irradiation unit disposed in the gap between the opposing surfaces. FIG. 6 is an explanatory diagram illustrating a state in which the irradiation unit of FIG. 5 has been moved outward from the gap between the opposing surfaces. FIG. 7 is an explanatory diagram illustrating a process of abutting and welding the opposing surfaces of one of the segments of FIG. 6 and the other of the segments. FIG. 8 is an explanatory diagram showing a modified example of the opposing surfaces of FIG. 5. FIG. 9 is an explanatory diagram illustrating a process of abutting and welding the opposing surfaces of one of the segments of FIG. 8 and the other of the segments. FIG. 10 is an explanatory diagram showing a modified example of the reinforcing rib in a front view of the silencer. FIG. 11 is an explanatory diagram showing another modified example of the reinforcing rib in a front view of the silencer. FIG. 12 is an explanatory diagram showing another form of silencer in a front view. FIG. 13 is an explanatory diagram showing an example of a longitudinal cross section of one divided body and the other divided body in a separated state. FIG. 14 is an explanatory diagram showing a process of irradiating each opposing surface of one divided body and the other divided body in FIG. 13 with infrared rays from an irradiation unit disposed in the gap between the opposing surfaces of the one divided body and the other divided body. FIG. 15 is an explanatory diagram showing a process of moving the irradiation unit in FIG. 14 outward from the gap between the opposing surfaces and then abutting and welding the opposing surfaces of the one divided body and the other divided body. FIG. 16 is an explanatory diagram showing a modified example of each opposing surface in FIG. 13. FIG. 17 is an explanatory diagram showing a process of abutting and welding the opposing surfaces of the one divided body and the other divided body in FIG. 16. Fig. 18 is an explanatory diagram illustrating another embodiment of the silencer as seen from the front. Fig. 19 is an explanatory diagram illustrating the silencer of Fig. 18 as seen in vertical cross section. Fig. 20 is an explanatory diagram illustrating the silencer of Fig. 18 as seen in horizontal cross section. Fig. 21 is an explanatory diagram illustrating one divided body and the other divided body of Fig. 19 in a separated state. Fig. 22 is an explanatory diagram illustrating one divided body and the other divided body of Fig. 20 in a separated state.Fig. 23 is an explanatory diagram illustrating a process of irradiating infrared rays onto the opposing surfaces of one divided body and the other divided body of Fig. 22 from an irradiation unit disposed in the gap between the opposing surfaces. Fig. 24 is an explanatory diagram illustrating a state in which the irradiation unit of Fig. 23 has been moved outward from the gap between the opposing surfaces. Fig. 25 is an explanatory diagram illustrating a process of abutting and welding the opposing surfaces of one divided body and the other divided body of Fig. 24 together. Fig. 26 is an explanatory diagram showing a modified example of the opposing surfaces of Fig. 22. Fig. 27 is an explanatory diagram illustrating a process of irradiating infrared rays onto the opposing surfaces of one divided body and the other divided body of Fig. 26 and then abutting and welding the opposing surfaces together. Fig. 28 is an explanatory diagram illustrating a process of heating the opposing surfaces of one divided body and the other divided body of another form of silencer by a hot plate disposed in the gap between the opposing surfaces. Fig. 29 is an explanatory diagram illustrating a process of heating each of the opposing surfaces of one divided body and the other divided body constituting yet another form of silencer by a hot plate arranged in the gap between the opposing surfaces of the other divided body. Fig. 30 is an explanatory diagram illustrating a process of heating each of the opposing surfaces of one divided body and the other divided body constituting yet another form of silencer by a hot plate arranged in the gap between the opposing surfaces of the other divided body.

[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 Figures 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 and flows 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 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. This resin may be any of a variety of known moldable resins. Examples include nylon resin (such as nylon 66), polypropylene, and ABS resin.

[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 of the segments 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 of the segments 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 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 of the segments 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 these parts 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 is 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, is not present), 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, is not present), and the opposing surfaces protrude outward. Therefore, the joints between the segments 6A, 8A (the portions corresponding to the opposing surfaces 7, 9) function as circumferential ribs. The inner and outer diameters of each opposing surface 7, 9 can also be the same as those of the surrounding body portion 2 (the portion where the circumferential ribs 5a, 5b are not present).

[0017] The expanded tube section 3 is a tubular body (a cylindrical body in this embodiment) that expands in diameter 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 convex arc-shaped, 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 concave arc-shaped, 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 barrel 2 so as to reinforce the barrel 2. In this embodiment, the plurality of circumferential ribs 5a are arranged at intervals in the axial direction. The circumferential ribs 5a may be arranged at equal intervals in the axial direction. The circumferential ribs 5a are arranged at least in the axial center of the barrel 2.

[0020] The protruding height of the circumferential ribs 5 a (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 5 a are determined appropriately based on the pressure resistance required of the silencer 1, etc.

[0021] In this embodiment, a circumferential rib 5b is provided on the inner peripheral surface of the body 2 so as to extend continuously in the circumferential direction. The circumferential rib 5b is primarily intended to improve the sound deadening effect, but also has the effect of reinforcing the body 2. In this embodiment, a plurality of 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 peripheral 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 5 a, 5 b is not limited to a semicircular shape or other shape with an arc-shaped top, but may be a triangular shape, a square shape, or other polygonal shape, etc. Having an arc-shaped top is advantageous in improving the durability of the circumferential ribs 5 a, 5 b.

[0024] As in this embodiment, the circumferential ribs 5a and 5b are preferably arranged offset in the axial direction. That is, the circumferential ribs 5a and 5b should be arranged so as not to overlap in the axial direction. If the circumferential ribs 5a and 5b were arranged so as to 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 the 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 types of known infrared welding devices can be used, and the device 10 includes 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 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 opposing surface 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 of the retaining portions 12a is moved axially toward 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 separation distance, 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 irradiated infrared rays, the irradiation time, the distance between the irradiating unit 11 and each of the opposing surfaces 7, 9, and the pressure applied to the opposing surfaces 7, 9 vary slightly depending on the specifications of the divided bodies 6A, 8A. Therefore, a preliminary test is 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 joint parts, damage will be concentrated in areas with low joint strength, so being able to more uniformly join the opposing surfaces 7, 9 together greatly contributes to improving durability.

[0033] The opposing surfaces 7, 9 protrude outward from 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 in 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] 2, in the piping system of an automotive air conditioner, refrigerant C flows in through one pipe section 4, passes through the expanded pipe section 3, the body section 2, and the expanded pipe section 3, and flows out of the other pipe section 4, repeatedly circulating. In the expanded pipe section 3, the refrigerant C flows along the inner circumferential surface. In this embodiment, the circumferential rib 5b protruding from the inner circumferential surface of the body section 2 interferes with the flowing refrigerant C, thereby canceling out the noise and pulsation caused by the flowing 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 (the left-right direction in Fig. 8) over the entire circumferential length. The divided bodies 6A, 8A of Fig. 8 differ from the divided bodies 6A, 8A of 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 the 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 fit 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 the divided bodies 6A and 8A together and integrates them.

[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 respective 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 bonding 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 bonding strength between the divided bodies 6A, 8A.

[0042] 10, in addition to the circumferential ribs 5a, axial ribs 5c extending in the axial direction may be provided 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. The specification including the axial ribs 5c in addition to the circumferential ribs 5a is advantageous in further improving the durability of the body portion 2 (silencer 1).

[0044] Instead of the axial ribs 5c shown in Fig. 10, 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, as shown in Fig. 11. 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 parts transversely in the axial direction. More specifically, each divided body 6A, 8A has a shape in which the silencer 1 is divided into two parts along a direction in which the silencer 1 is uniformly inclined with respect to the axial direction (the inclination angle B is 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 divided body 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. That is, this silencer 1 differs from the silencer 1 shown in Figs. 1 and 2 in the specifications of the opposing surfaces 7, 9. 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, without contacting 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 relative to the axial direction and that crosses 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 divided bodies 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 (the left-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, 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, 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 opposing surfaces 7, 9. The opposing surfaces 7, 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. 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.

[0054] 17, the peripheral walls of the opposing surfaces 7 and 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 and 8A (opposing surfaces 7 and 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. 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 without overlapping in the wall thickness direction over the entire circumferential length. This is advantageous for improving the joining 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 manner in the wall thickness direction over the entire axial length.

[0057] That is, this silencer 1 differs from the silencer 1 illustrated in Figures 1 and 2 in the specifications of the opposing surfaces 7, 9 (the dividing direction of the divided bodies 6B, 8B). The divided bodies 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 Figures 1 and 2. The various arrangements described for the silencer 1 illustrated in Figures 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, but without contacting 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 outside the respective 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 a specification 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, 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, 9, which are spaced apart and facing 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 axial length, the shape of the irradiation unit 11 is shaped to fit the opposing surfaces 7, 9. The opposing surfaces 7, 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 Figure 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 segment 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 respective 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. Therefore, the area of ​​the opposing surfaces 7, 9 is larger than 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 the 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, melting 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, 15b that move toward and away from each other. At least one of the holders 15a, 15b must be able to move toward and away from the other. The divided bodies 6A, 8A are held by the holders 15a, 15b, with the opposing surfaces 7, 9 facing each other but spaced apart. In this state, the hot plate 14 is inserted into the gap between the opposing surfaces 7, 9, and is positioned without contacting the opposing surfaces 7, 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, which is 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), so that the molten opposing surfaces 7 and 9 face 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, 9 come into contact with each other without any gaps. Alternatively, 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, 15b 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 together. In this way, the silencer 1 is manufactured by joining the respective segments 6A, 8A together. That is, when using the hot plate welding device 13, the only difference is that the irradiation portion 11, which is used when using 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 carried out quickly, for example, within 1 to 10 seconds. Furthermore, the hot plate 14 is preheated to a predetermined temperature before being inserted between the opposing surfaces 7, 9, thereby shortening the manufacturing process time. 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, 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, 9, as shown in FIG. 29 , to melt the opposing surfaces 7, 9. To maintain a constant distance between the hot plate 14 and the opposing surfaces 7, 9 over the entire circumferential length, the hot plate 14 is shaped to conform to the opposing surfaces 7, 9. Next, the hot plate 14 is moved outside the respective segments 6A, 8A (in a direction perpendicular to the axial direction) so that the molten opposing surfaces 7, 9 face each other with a gap between them. Next, at least one of the holding portions 15a, 15b is brought close to the other, causing the molten opposing surfaces 7, 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, a hot plate 14 is brought 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), so that the molten opposing surfaces 7, 9 face each other 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 the divided bodies 6A (6B), 8A (8B) have any other shape, they 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.

[0079] DESCRIPTION OF SYMBOLS 1 silencer 2 body 3 expanded tube section 4 pipe section 5a, 5b circumferential rib 5c axial rib 5d diagonal rib 6A, 6B one divided body 7 opposing surface 8A, 8B other divided body 9 opposing surface 10 infrared welding device 11 irradiation section 12a, 12b holding section 13 hot plate welding device 14 hot plate 15a, 15b holding section C refrigerant

Claims

1. A method for manufacturing a resin silencer 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, the method comprising: molding the silencer into two divided bodies across the axial direction or along the axial direction using resin molding; irradiating the opposing surfaces of each divided body with infrared rays or bringing a hot plate close to each other to melt the opposing surfaces; and welding the molten opposing surfaces together to join the divided bodies together.

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

3. A method for manufacturing a resin silencer as described in claim 1, wherein each of the divided bodies is a divided body in which the silencer is divided into two along a direction that is uniformly inclined relative to the axial direction.

4. A 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. A method for manufacturing a resin silencer as described in claim 2 or 3, 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 circumferential length.

6. A method for manufacturing a resin silencer as described in claim 2 or 3, in which each divided body is a divided body shaped so that the peripheral walls of each opposing surface are overlapped in the wall thickness direction over the entire circumferential length.

7. 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. 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 overlapped in the wall thickness direction over the entire axial length.

Images