Method for manufacturing resin silencer

Abstract

The present invention provides a highly versatile manufacturing method that can be applied to the manufacture of a silencer obtained by joining two divided resin bodies, even if respective joining portions of the divided bodies have various shapes. Provided is a silencer 1 in which a small-diameter pipe part 4 is connected to both axial end parts of a cylindrical body part 2 via a pipe expansion part 3. The silencer is formed through resin molding of divided bodies 6A, 8A having a shape divided into two parts across an axial direction or along the axial direction. Respective opposing faces 7, 9 of the divided bodies 6A, 8A are pressure-bonded to each other, and while in this state, ultrasonic wave or sliding vibrations are applied to at least one of the opposing faces 7, 9 to weld the opposing faces 7, 9 to each other, thus joining and uniting the divided bodies 6A, 8A with each other.

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 across the axial direction or along the axial direction using resin molding, and while the opposing surfaces of each of the split bodies are pressed together, ultrasonic or sliding vibrations are applied to at least one of the opposing surfaces to weld the opposing surfaces together and join the split bodies together into a single unit.

[0008] According to the present invention, ultrasonic waves or sliding vibrations are applied to at least one of the opposing surfaces in the pressure-bonded state to weld the opposing surfaces together, so that the joining portions of the segments are not limited to being cylindrical, and segments having other shapes can be joined together and integrated. A segment in which the silencer is divided into two across the axial direction can be used, or a segment in which the silencer is divided into two along 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 viewed from the front. FIG. 2 is an explanatory diagram illustrating the silencer of FIG. 1, as viewed from the longitudinal cross section. FIG. 3 is an explanatory diagram illustrating one of the segments of FIG. 2 separated from the other segment. FIG. 4 is an explanatory diagram illustrating the structure of one of the segments, taken along the A-A cross section of FIG. 3. FIG. 5 is an explanatory diagram illustrating a process of applying ultrasonic waves to the opposing surfaces of the one segment of FIG. 3, which are pressed together. FIG. 6 is an explanatory diagram showing a modification of the opposing surfaces of FIG. 3. FIG. 7 is an explanatory diagram illustrating a process of applying ultrasonic waves to the opposing surfaces of the one segment of FIG. 6, which are pressed together. FIG. 8 is an explanatory diagram showing a modification of the reinforcing rib in a front view of the silencer. FIG. 9 is an explanatory diagram showing another modification of the reinforcing rib in a front view of the silencer. FIG. 10 is an explanatory diagram showing another form of silencer, as viewed from the front. FIG. 11 is an explanatory diagram illustrating a longitudinal cross-sectional view of one divided body and the other divided body of FIG. 10 in a separated state. FIG. 12 is an explanatory diagram illustrating a process of applying ultrasonic waves with the opposing surfaces of one divided body and the other divided body of FIG. 11 pressed together. FIG. 13 is an explanatory diagram showing a modified example of each opposing surface of FIG. 11. FIG. 14 is an explanatory diagram illustrating a process of applying ultrasonic waves with the opposing surfaces of one divided body and the other divided body of FIG. 13 pressed together. FIG. 15 is an explanatory diagram illustrating a front view of another embodiment of a silencer. FIG. 16 is an explanatory diagram illustrating a longitudinal cross-sectional view of the silencer of FIG. 15. FIG. 17 is an explanatory diagram illustrating a cross-sectional view of the silencer of FIG. 15. FIG. 18 is an explanatory diagram illustrating a separated state of one divided body and the other divided body of FIG. 16. FIG. 19 is an explanatory diagram illustrating a separated state of one divided body and the other divided body of FIG. 17. Fig. 20 is an explanatory diagram illustrating a process of applying ultrasonic waves in a state in which the opposing surfaces of one divided body and the other divided body in Fig. 19 are pressed together. Fig. 21 is an explanatory diagram showing a modified example of each opposing surface in Fig. 19. Fig. 22 is an explanatory diagram illustrating a process of applying ultrasonic waves in a state in which the opposing surfaces of one divided body and the other divided body in Fig. 21 are pressed together. Fig. 23 is an explanatory diagram illustrating, in vertical cross section, a process of applying sliding vibration in a state in which the opposing surfaces of one divided body and the other divided body are pressed together.Fig. 24 is an explanatory diagram illustrating, in a vertical cross-sectional view, a process of applying sliding vibrations to one and the other divided bodies constituting another form of silencer, with opposing surfaces thereof pressed against each other. Fig. 25 is an explanatory diagram illustrating, in a horizontal cross-sectional view, a process of applying sliding vibrations in a direction perpendicular to the axial direction, with opposing surfaces thereof pressed against each other, with opposing surfaces thereof pressed against each other. Fig. 26 is an explanatory diagram illustrating, in a front view, a process of applying sliding vibrations in the axial direction, with opposing surfaces thereof pressed against each other, with opposing surfaces thereof pressed against each other.

[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 divided bodies 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 divided bodies 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°). Each of the divided bodies 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 peripheral walls of the opposing surfaces 7, 9 are butted together in a non-overlapping manner in the wall thickness direction (left-right direction in Figures 2 and 3) along the entire circumferential length. However, in this embodiment, one opposing surface 7 has a convex, annular engaging portion 7a, and the other opposing surface 9 has a concave, annular engaging portion 9a, with the engaging portion 7a shaped to fit into the engaging portion 9a. Only these engaging portions 7a, 9a overlap in the wall thickness direction. The engaging portions 7a, 9a are not limited to annular shapes, and any desired shape of engaging convex and concave portions may be used as long as they can engage with each other and prevent misalignment between the opposing surfaces 7, 9. For example, the engaging portions 7a may be convex portions of a desired shape arranged at intervals in the circumferential direction on the opposing surface 7, and the engaging portions 9a may be concave portions of a desired shape arranged at intervals in the circumferential direction on the opposing surface 9. The engaging portions 7a, 9a are not required and can be provided optionally.

[0016] 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.

[0017] The opposing surfaces 7, 9 are welded together, and in the manufactured silencer 1, the boundary between the opposing surfaces 7, 9 is unclear. In the drawings, the boundary 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).

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] An example of a procedure for manufacturing the silencer 1 will now be described.

[0027] 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.

[0028] Next, as shown in Fig. 5, the opposing surfaces 7, 9 of the divided bodies 6A, 8A are brought into a pressure-bonded state. In this state, ultrasonic waves are applied to at least one of the opposing surfaces 7, 9 using an ultrasonic welding device 10, thereby welding the opposing surfaces 7, 9 together. In this way, the divided bodies 6A, 8A are joined and integrated together, and the silencer 1 is manufactured.

[0029] More specifically, various known types of ultrasonic welding device 10 can be used, and includes a horn 11 that emits ultrasonic waves and a receiving base 12. The other divided body 8A is held and fixed by the receiving base 12. The facing surface 7 of one divided body 6A is brought into contact with the facing surface 9 of this divided body 8A. Here, by fitting the convex engaging portion 7a into the concave engaging portion 9a, the facing surfaces 7, 9 can be accurately positioned and brought into contact with each other while preventing misalignment.

[0030] Next, the horn 11 is brought into contact with the end face of the pipe portion 4 of one of the segments 6A, and pressure is applied to the segment 6A toward the other segment 8A, bringing the opposing surfaces 7, 9 into a pressure-bonded state. Thereafter, the positions (axial positions) of the segments 6A, 8A are maintained. Next, ultrasonic waves are emitted from the horn 11 and applied to one of the segments 6A for a predetermined period of time, whereby the ultrasonic waves are propagated and applied to the opposing surfaces 7, 9. The applied ultrasonic waves cause minute vibrations, which heat and melt the resins of the opposing surfaces 7, 9. The molten resin of the opposing surfaces 7, 9 then cools and hardens, welding the opposing surfaces 7, 9 together.

[0031] The frequency of the applied ultrasonic waves is, for example, 15 kHz to 200 kHz, more preferably 20 kHz to 40 kHz. The amplitude is, for example, 5 μm to 50 μm, and the duration of application of the ultrasonic waves is, for example, 0.5 seconds to 5 seconds. The optimal ranges for the ultrasonic frequency, amplitude, application duration, and pressure applied to the opposing surfaces 7, 9 vary slightly depending on the specifications of the segments 6A, 8A. Therefore, a preliminary test is conducted to determine these optimal ranges, and the opposing surfaces 7, 9 are welded together using the determined optimal ranges.

[0032] The vibrations generated on the opposing surfaces 7 and 9, which are welded by applying ultrasonic waves, are very small, which is advantageous in suppressing the generation of burrs due to the molten resin. In other words, it is possible to omit the finishing work on the joints of the divided bodies 6A and 8A (the parts corresponding to the opposing surfaces 7 and 9).

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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).

[0038] As shown in Fig. 6, 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. 6) over the entire circumferential length. The divided bodies 6A, 8A in Fig. 6 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.

[0039] 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. As illustrated in Figure 7, with the opposing surfaces 7, 9 of the divided bodies 6A, 8A pressed together, ultrasonic waves are applied from a horn 11 to at least one of the opposing surfaces 7, 9, thereby welding the opposing surfaces 7, 9 together.

[0040] 7, 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 suppressing misalignment of the divided bodies 6A, 8A (opposing surfaces 7, 9) and crimping them together before applying ultrasonic waves.

[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] 8, 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. 8, 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. 9. 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. 10 is manufactured by joining and integrating two divided bodies 6A, 8A shown in Fig. 11. Each divided body 6A, 8A has a shape in which the silencer 1 is divided into two parts across 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] In the silencer 1 shown in Fig. 10, the opposing surfaces 7, 9 of the respective divided bodies 6A, 8A are not 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, 8A illustrated in Figure 11 are manufactured by resin injection molding. Next, as illustrated in Figure 12, the opposing surfaces 7, 9 of the divided bodies 6A, 8A are pressed together, and ultrasonic waves are applied to at least one of the opposing surfaces 7, 9 using an ultrasonic welding device 10 to weld the opposing surfaces 7, 9 together. In this way, the divided bodies 6A, 8A are joined together and integrated to manufacture the silencer 1.

[0048] 12, 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.

[0049] 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.

[0050] As shown in Fig. 13, 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. 13) over the entire circumferential length. The divided bodies 6A, 8A in Fig. 13 differ from the divided bodies 6A, 8A in Fig. 11 only in the specifications of the opposing surfaces 7, 9, and the other specifications are the same.

[0051] The procedure for manufacturing this silencer 1 is substantially the same as the procedure for manufacturing the silencer 1 illustrated in Fig. 7. As illustrated in Fig. 14, with the opposing surfaces 7, 9 of the divided bodies 6A, 8A pressed together, ultrasonic waves are applied from a horn 11 to at least one of the opposing surfaces 7, 9, thereby welding the opposing surfaces 7, 9 together.

[0052] 14, 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 suppressing misalignment of the divided bodies 6A, 8A (opposing surfaces 7, 9) and crimping them together before applying ultrasonic waves.

[0053] 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. As a result, the areas of the opposing surfaces 7, 9 are larger than 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 increases the bonding area between the opposing surfaces 7, 9, which is advantageous for improving the bonding strength between the segments 6A, 8A.

[0054] The silencer 1 of the embodiment illustrated in Figures 15 to 17 is manufactured by joining together two divided bodies 6B, 8B illustrated in Figures 18 and 19. 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 opposing surfaces 7, 9 are butted together in a non-overlapping manner in the wall thickness direction over the entire axial length.

[0055] 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.

[0056] 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, 8B illustrated in Figures 18 and 19 are manufactured by resin injection molding. Next, as illustrated in Figure 20, the opposing surfaces 7, 9 of the divided bodies 6B, 8B are pressed together, and ultrasonic waves are applied to at least one of the opposing surfaces 7, 9 using an ultrasonic welding device 10 to weld the opposing surfaces 7, 9 together. In this way, the divided bodies 6B, 8B are joined and integrated to manufacture the silencer 1.

[0057] 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.

[0058] As shown in Fig. 21, 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 overlap in the wall thickness direction over the entire axial length. The divided bodies 6A, 8A in Fig. 21 differ from the divided bodies 6A, 8A in Fig. 19 only in the specifications of the opposing surfaces 7, 9, and the other specifications are the same.

[0059] The procedure for manufacturing this silencer 1 is substantially the same as the procedure for manufacturing the silencer 1 illustrated in Fig. 20. As illustrated in Fig. 22, with the opposing surfaces 7, 9 of the divided bodies 6A, 8A pressed together, ultrasonic waves are applied from a horn 11 to at least one of the opposing surfaces 7, 9, thereby welding the opposing surfaces 7, 9 together.

[0060] 22, 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 suppressing misalignment of the divided bodies 6A, 8A (opposing surfaces 7, 9) and crimping them together before applying ultrasonic waves.

[0061] 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.

[0062] In the various embodiments for manufacturing the silencer 1 described above, ultrasonic waves are used to weld the opposing surfaces 7, 9 together, but it is also possible to weld the opposing surfaces 7, 9 together by applying slide vibration instead of ultrasonic waves. Therefore, a method for manufacturing the silencer 1 using the slide vibration welding device 13 will be described below.

[0063] 1 and 2, the opposing surfaces 7 and 9 of the divided bodies 6A and 8A are brought into a pressure-bonded state as shown in Fig. 23. In this state, a slide vibration is applied to one of the opposing surfaces 7 using a slide vibration welding device 13, thereby welding the opposing surfaces 7 and 9 together.

[0064] Although the segments 6A and 8A in FIG. 23 do not have circumferential ribs 5b, they can also be configured to have circumferential ribs 5b. Because sliding vibrations along the opposing surfaces 7 and 9 are applied to the segment 6A, it is desirable that the opposing surfaces 7 and 9 be flat in the sliding direction. Therefore, the segments 6A and 8A in FIG. 23 are configured not to have the engaging portions 7a and 9a shown in FIG. 3. 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.

[0065] Various known types of slide vibration welding device 13 can be used, and include a sliding head 14, a holding portion 14a that holds one of the divided bodies 6A and is slidably vibrated by the sliding head 14, and a holding base 15. The other divided body 8A is held and fixed by the holding base 15. The opposing surface 7 of one divided body 6A held by the holding portion 14a is brought into contact with the opposing surface 9 of the other divided body 8A held and fixed by the holding base 15, and the divided body 6A is pressed toward the other divided body 8A, thereby crimping the opposing surfaces 7 and 9 together. Thereafter, the axial positions of the respective divided bodies 6A and 8A are maintained.

[0066] Then, by causing the slide head 14 to slide back and forth along the opposing surfaces 7 and 9, slide vibration is applied to the holding portion 14a and one of the divided bodies 6A (opposing surface 7) for a predetermined time. This slide vibration causes the opposing surfaces 7 and 9 to rub against each other, generating heat and melting the resin in each. The molten resin on the opposing surfaces 7 and 9 then cools and hardens, welding the opposing surfaces 7 and 9 together.

[0067] The frequency of the applied slide vibration is, for example, 200 kHz to 250 kHz. The amplitude is, for example, 0.5 mm to 2.0 m, and the duration of application of the ultrasonic waves is, for example, 0.5 seconds to 5 seconds. The optimal ranges for the ultrasonic frequency, amplitude, application duration, and pressure applied to the opposing surfaces 7 and 9 vary slightly depending on the specifications of the segments 6A and 8A. Therefore, a preliminary test should be conducted to determine these optimal ranges, and the segments 6A and 8A can be welded together using the determined optimal ranges.

[0068] It is desirable that the area of ​​the opposing surfaces 7, 9 that rub against each other due to the sliding vibration be as large as possible. In the method of applying sliding vibration, the opposing surfaces 7, 9 slide relatively against each other at high speed, making it possible to more quickly weld the opposing surfaces 7, 9 that have a large area together.

[0069] 10 in which the opposing surfaces 7, 9 extend at a uniform incline relative to the axial direction, is manufactured by applying a sliding vibration to one of the opposing surfaces 7 using a slide vibration welding device 13 while the opposing surfaces 7, 9 of the divided bodies 6A, 8A are pressed together, as shown in FIG. 24. This joins and integrates the divided bodies 6A, 8A to manufacture the silencer 1. The vibration direction of the applied sliding vibration is along the opposing surfaces 7, 9, so that one divided body 6A is held by a holder 14a in a state inclined relative to the slide head 14, and the other divided body 8A is held and fixed by a holder 15 in a state inclined relative to the slide head 14.

[0070] 15 to 17 in which the opposing surfaces 7, 9 extend along the axial direction, the opposing surfaces 7, 9 of the respective divided bodies 6B, 8B of the silencer 1, which extend along the axial direction, are pressed together as shown in Fig. 25. In this state, a slide vibration is applied to one of the opposing surfaces 7 using a slide vibration welding device 13, thereby welding the opposing surfaces 7, 9 together. In this embodiment, the vibration direction of the slide vibration applied to one of the divided bodies 6B is perpendicular to the axial direction.

[0071] 15 to 17, the vibration direction of the slide vibration may be set to the axial direction when manufacturing the silencer 1 illustrated in Fig. 15 to 17 using the slide vibration welding device 13. That is, in this case, the opposing surfaces 7 and 9 are pressed together as illustrated in Fig. 26, and then the slide vibration welding device 13 is used to apply axial slide vibration to one of the opposing surfaces 7, thereby welding the opposing surfaces 7 and 9 together.

[0072] When the silencer 1 is manufactured using the slide vibration welding device 13, the various arrangements described in the case where the ultrasonic welding device 10 is used can also be applied.

[0073] As in the various embodiments of the silencer 1 described above, ultrasonic or sliding vibration is applied to at least one of the opposed surfaces 7, 9 in the crimped state to weld the opposed surfaces 7, 9 together, so the joining portions of the divided bodies 6A (6B), 8A (8B) are not limited to being cylindrical, and even if the joined bodies have other shapes, 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.

[0074] In addition, in the method of welding the opposing surfaces 7, 9 together using the ultrasonic welding device 10, the opposing surfaces 7, 9 only vibrate slightly, so it is also possible to form the opposing surfaces 7, 9 into a zigzag shape that fits together. Therefore, the method of applying ultrasonic waves is more advantageous than the method of applying sliding vibration for manufacturing silencers 1 with a wider variety of shapes.

[0075] REFERENCE SIGNS LIST 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 7a engagement section 8A, 8B other divided body 9 opposing surface 9a engagement section 10 ultrasonic welding device 11 horn 12 receiving base 13 slide vibration welding device 14 slide head 14a holding section 15 holding base 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 by resin molding; applying ultrasonic or sliding vibrations to at least one of the opposing surfaces of each of the divided bodies while the opposing surfaces are pressed together, thereby welding the opposing surfaces together and joining the divided bodies together into a single unit.

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 any one of claims 2 to 4, in which engaging portions that engage with each other are formed on each of the opposing surfaces, and the ultrasonic waves are applied to each of the opposing surfaces in a state in which the engaging portions are engaged with each other and the opposing surfaces are pressed together.

6. A method for manufacturing a resin silencer according to any one of claims 2 to 4, wherein, with the opposing surfaces pressed together, one of the opposing surfaces is fixed in a predetermined position, and a sliding vibration having a frequency of 200 Hz to 250 Hz and an amplitude of 2.0 mm or less is applied to the other opposing surface.

7. 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.

8. 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 divided into two so that they overlap in the wall thickness direction over the entire circumferential length.

9. 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.

10. 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.

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