Method for manufacturing a resin silencer and resin silencer

Abstract

To provide a resin-made silencer connected to piping of an air conditioner for an automobile, and having sufficient pressure resistance against inner pressure while being light in weight, and a manufacturing method of the same.SOLUTION: A resin-made silencer has: a cylindrical flow stop wall part 18 in which a resin-made insertion-side component 2 protrusively arranged with a circumferential-direction rib 10a at an external peripheral face of a flank part 3, and having an insertion part 4 at one end part of the flank part 3 in an axial core direction, and a pipe part 9 continuously connected to the other end part via a diameter-expanded part 8, and a resin-made receiving-side component 11 protrusively arranged with a circumferential-direction rib 21a at an external peripheral face of a flank part 12, and having a receiving part 13 at the other end part of the flank part 12 in an axial core direction, and a pipe part 20 continuously connected to one end part via a diameter-expanded part 19 are inserted into a circular ring-shaped groove 14 of the receiving part 13 of the insertion part 4, and also in which the flank parts 3, 12 joined to each other by spin-welding a contact portion of the insertion part 4 and the circular ring-shaped groove 14 are formed as cylinder parts, and which is continuously connected to the joining portion while separating to an external peripheral side; and a cylindrical flow stop wall part 16 which is continuously connected to the joining portion while separating to an internal peripheral side.SELECTED DRAWING: Figure 6

Description

Technical Field

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[0001] The present invention relates to a method for manufacturing a resin silencer connected to a pipe of an automotive air conditioner and a resin silencer.

Background Art

[0002] A silencer is connected to a pipe of an automotive air conditioner to suppress noise caused by the flow of a circulating refrigerant (see, for example, Patent Documents 1 and 2). The silencer is a cylindrical body having a larger diameter than the connected pipe and is mainly formed of metal.

[0003] In recent years, with the weight reduction of automobiles, weight reduction of pipes has also been demanded. When making a conventional metal silencer into a resin one for weight reduction, it is necessary to ensure sufficient pressure resistance against the internal pressure exerted by the circulating refrigerant. In addition, since the silencer is connected to a pipe having a smaller diameter, it is necessary to change the thickness from the large-diameter cylindrical portion (body portion) to the connected pipe. Depending on the degree of this thickness change, excessive stress may locally occur in the silencer on which the internal pressure acts, making it difficult to ensure sufficient pressure resistance. To ensure pressure resistance, thickening the peripheral wall of the cylindrical silencer is disadvantageous for weight reduction. Therefore, there is room for improvement in manufacturing a resin silencer that is lightweight and has sufficient pressure resistance against internal pressure.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The object of the present invention is to provide a method for manufacturing a resin silencer that is connected to the piping of an automobile air conditioner and is lightweight yet has sufficient pressure resistance against internal pressure, as well as a resin silencer. [Means for solving the problem]

[0006] To achieve the above objective, the present invention provides a method for manufacturing a resin silencer, which is a method for manufacturing a resin silencer connected to the piping of an automobile air conditioner, comprising: an insertion-side component having an annular circumferential rib protruding from the outer surface of a cylindrical body, an insertion portion at one end of the body in the axial direction, and a pipe portion smaller in diameter than the body connected to the other end in the axial direction via an expanded pipe portion that expands toward the body; and a receiving-side component having an annular circumferential rib protruding from the outer surface of a cylindrical body, a receiving portion into which the insertion portion is inserted at the other end of the body in the axial direction, and a pipe portion smaller in diameter than the body connected to the one end in the axial direction via an expanded pipe portion that expands toward the body, each of which is manufactured by resin injection molding. The receiving portion is formed by spin welding the contact portion between the insertion portion and the annular groove, thereby joining the body portion of the insertion portion and the body portion of the receiving portion to form an integrated cylindrical portion. The receiving portion has an annular groove into which the cylindrical insertion portion is inserted, and a cylindrical flow-stopping wall portion is connected to the outer circumference of the annular groove at a distance from it. The tip surface of the insertion portion inserted into the annular groove is brought into contact with the bottom surface of the annular groove and pressed, and the outer surface of the insertion portion is brought into contact with the outer circumference wall of the annular groove, while the inner surface of the insertion portion is left in a non-contact state with the inner circumference wall of the annular groove. By rotating the insertion portion and the receiving portion relative to each other around their axes, the contact portion between the insertion portion and the annular groove is spin-welded, thereby joining the body portion of the insertion portion and the body portion of the receiving portion to form an integrated cylindrical portion.

[0007] The resin silencer of the present invention is a resin silencer connected to the piping of an automobile air conditioner, comprising: a resin insertion-side component having an annular circumferential rib protruding from the outer surface of a cylindrical body, with an insertion portion at one end of the body in the axial direction, and a pipe portion smaller in diameter than the body connected to the other end in the axial direction via an expanded pipe portion that expands toward the body; and a receiving portion having an annular circumferential rib protruding from the outer surface of a cylindrical body, with the insertion portion being inserted into the other end of the body in the axial direction. A resin receiving part, having a pipe section smaller in diameter than the body section connected to its end via an expanded pipe section that widens toward the body section, is joined to the receiving part with the insertion section inserted into the receiving part, and the body section of the insertion part and the body section of the receiving part, which are integrated by this joining, form a cylindrical section, and has a cylindrical flow-stopping wall section that is spaced apart and connected to the outer circumference of the joint between the insertion part and the receiving part, and a cylindrical flow-stopping wall section that is spaced apart and connected to the inner circumference of the joint section. [Effects of the Invention]

[0008] According to the present invention, a resin silencer can be obtained in which the insertion-side part and the receiving-side part are joined together with the insertion part inserted into the receiving part, thereby forming cylindrical bodies at the joint. Since there is a cylindrical flow-stopping wall connected at a distance from the outer circumference of the joint between the insertion part and the receiving part, and a cylindrical flow-stopping wall connected at a distance from the inner circumference of the joint, burrs generated during the joining of the joint are prevented from protruding from the inner and outer surfaces of the silencer by these flow-stopping walls, which is advantageous for stably and firmly joining the insertion-side part and the receiving-side part. Furthermore, since each of the bodies and the pipe section is connected via the expanded pipe section, it is possible to avoid the generation of locally excessive stress in the region between each of the bodies and the pipe section when internal pressure is applied. Furthermore, the circumferential ribs protruding from the outer surface of each of the aforementioned body sections resist internal pressure, thus preventing excessive localized stress from occurring in each body section, expanded section, or joint. Therefore, it is possible to obtain a silencer that is lightweight, made of resin, yet possesses sufficient pressure resistance against internal pressure. [Brief explanation of the drawing]

[0009] [Figure 1] This is an explanatory diagram illustrating an embodiment of a silencer in a front view. [Figure 2] This is an explanatory diagram illustrating the silencer shown in Figure 1 in a longitudinal cross-sectional view. [Figure 3] This is an explanatory diagram illustrating a magnified view of the joint portion in Figure 2. [Figure 4] This is an explanatory diagram illustrating the insertion-side component and the receiving-side component that make up the silencer shown in Figure 1, in a separated state and viewed from the front. [Figure 5] Figure 4 is an explanatory diagram illustrating the insertion-side component and the receiving-side component in a longitudinal cross-sectional view. [Figure 6] Figure 5 is an explanatory diagram illustrating the state in which the insertion-side component and the receiving-side component are fitted together, in a longitudinal cross-sectional view. [Figure 7] This is an explanatory diagram illustrating an enlarged view of the fitting portion in Figure 6. [Figure 8]This is a cross-sectional view AA in Figure 6. [Figure 9] This is an explanatory diagram illustrating another embodiment of the silencer in a longitudinal cross-sectional view. [Figure 10] This is an explanatory diagram illustrating another embodiment of the silencer in a front view. [Figure 11] Figure 10 is a cross-sectional view of BB. [Figure 12] This is an explanatory diagram illustrating another embodiment of the silencer in a front view. [Modes for carrying out the invention]

[0010] The method for manufacturing a resin silencer and the resin silencer of the present invention will be described below based on the embodiments shown in the figures.

[0011] In the embodiment of the resin silencer 1 illustrated in Figures 1 to 3, pipe sections 9 and 20, which are smaller in diameter than the body sections 3 and 12, are connected to both ends of the cylindrical section (body section 3 and 12) in the axial direction via expanded pipe sections 8 and 19, respectively. The piping of an automobile air conditioner is connected to the pipe sections 9 and 20, respectively. The refrigerant C used in the air conditioner circulates inside the hollow silencer 1. The refrigerant C flows in from one pipe section 9 and out from the other pipe section 20. The dashed line CL in the figures indicates the axis of the silencer 1, passing through the center of the cross-sections of the body sections 3 and 12, expanded pipe sections 8 and 19, and pipe sections 9 and 20. The direction in which the axis CL extends is the axial direction.

[0012] The silencer 1 is formed by joining and integrating a resin insertion-side part 2 and a resin receiving-side part 11, as illustrated in Figures 4 and 5. The insertion-side part 2 and the receiving-side part 11 are basically made of the same resin. Known injection-molded resins are used as the resins for forming the insertion-side part 2 and the receiving-side part 11. For example, nylon resin (such as nylon 66), polypropylene, and ABS resin can be used.

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

[0014] The insertion-side component 2 has a body portion 3, an expanded pipe portion 8, and a pipe portion 9. The body portion 3 has an insertion portion 4 at one end in the axial direction (the lower end in the figure) and the expanded pipe portion 8 is arranged at the other end in the axial direction (the upper end in the figure). The expanded pipe portion 8 is a cylindrical body that expands in diameter from the pipe portion 9 toward the body portion 3, and the body portion 3 and the pipe portion 9 are connected via the expanded pipe portion 8.

[0015] The inclination angle of the peripheral wall of the expanded pipe portion 8 with respect to the axis CL is, for example, about 30° to 60°. Also, the boundary between the expanded pipe portion 8 and the body portion 3 is in a convex arc shape, and the arc radius (R1 dimension) of the outer surface of this boundary is, for example, about 10 mm to 20 mm. The arc radius (R2 dimension) of the inner surface of this boundary is set so that the thickness (the thickness between the outer surface and the inner surface) is constant. The boundary between the expanded pipe portion 8 and the pipe portion 9 is in a concave arc shape, and the arc radius (R3 dimension) of the outer surface of this boundary is, for example, about 10 mm to 20 mm. The arc radius (R4 dimension) of the inner surface of this boundary is set so that the thickness (the thickness between the outer surface and the inner surface) is constant. Therefore, the cylindrical body portion 3 and the cylindrical pipe portion 9 are smoothly connected by the expanded pipe portion 8 whose inner diameter and outer diameter gradually change.

[0016] On the outer peripheral surface of the body portion 3, in order to reinforce the body portion 3, circumferential ribs 10a that are continuous in the circumferential direction are protruding. In this embodiment, a plurality (five) of circumferential ribs 10a are arranged at intervals in the axial direction, but the number is, for example, in the range of 1 to 6. The circumferential ribs 10a may be arranged at equal intervals in the axial direction. The axial rib 10 is arranged at least in the central portion in the axial direction of the body portion 3.

[0017] The protrusion height of the circumferential ribs 10a (the amount of radial outward protrusion from the outer surface of the body 3) 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 10a are determined appropriately based on the pressure resistance required for the silencer 1.

[0018] In this embodiment, circumferential ribs 10b are provided on the inner surface of the body 3, extending continuously in the circumferential direction. These circumferential ribs 10b are primarily intended to improve sound absorption, but they also serve to reinforce the body 3. In this embodiment, multiple (five) circumferential ribs 10b are arranged at intervals in the axial direction, but the number of circumferential ribs 10b can range from, for example, 1 to 6. It is preferable to arrange the circumferential ribs 10b at equal intervals in the axial direction. Note that circumferential ribs 10b can be provided at will.

[0019] The protrusion height of the circumferential ribs 10b (the amount of radial inward protrusion from the inner circumferential surface of the body 3) 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 10b are determined appropriately based on the sound-dampening performance required of the silencer 1.

[0020] The cross-sectional shape of the circumferential ribs 10a and 10b is not limited to a semicircular shape or other shape with an arc-shaped top; triangular, quadrilateral, or other polygonal shapes can also be adopted. An arc-shaped top is advantageous for improving the durability of the circumferential ribs 10a and 10b.

[0021] It is desirable that the circumferential ribs 10a and 10b be offset in the axial direction, as in this embodiment. That is, it is preferable that the circumferential ribs 10a and 10b be arranged so that they do not overlap in the axial direction. If the circumferential ribs 10a and 10b overlap in the axial direction, the uneven distribution of resin in the body portion 3 will be excessive, which is disadvantageous for good injection molding.

[0022] The cylindrical insertion portion 4 has outer peripheral walls 5a and 5b, an inner peripheral wall 6, and a tip surface 7. The outer peripheral wall 5a has a smaller diameter than the outer peripheral wall 5b, and there is a step between the two.

[0023] The receiving component 11 has a body portion 12, an expanded pipe portion 19, and a pipe portion 20. The body portion 12 has a receiving portion 13 at one end in the axial direction (upper end in the figure) and an expanded pipe portion 19 at the other end in the axial direction (lower end in the figure). The body portion 12 and the pipe portion 20 are connected via the expanded pipe portion 19. A circumferential rib 21a is provided on the outer circumferential surface of the body portion 12, which is continuous in the circumferential direction, in order to reinforce the body portion 12. In this embodiment, a circumferential rib 21b is also provided on the inner circumferential surface of the body portion 12, which is continuous in the circumferential direction.

[0024] The insertion part 2 and the receiving part 11 differ in their insertion section 4 and receiving section 13, but the other parts (body section 3 and body section 12, expanded section 8 and expanded section 19, pipe section 9 and pipe section 20, circumferential rib 10a and circumferential rib 21a, circumferential rib 10b and circumferential rib 21b) are substantially the same. The inner diameter of body sections 3 and 12 is approximately 30mm to 60mm. The inner diameter of pipe sections 9 and 20 is approximately 10mm to 20mm. The thickness of the circumferential walls of body sections 3 and 12, expanded sections 8 and 19, and pipe sections 9 and 20 is approximately the same, for example, 2mm to 5mm.

[0025] The receiving portion 13 has an annular groove 14 and a cylindrical flow-stopping wall portion 18 that is spaced apart and connected to the outer circumference of the annular groove 14. The annular groove 14 has outer peripheral walls 15a and 15b, an inner peripheral wall 16, and a bottom surface 17. The outer peripheral wall 15a has a smaller diameter than the outer peripheral wall 15b, and there is a step between the two.

[0026] In assembly 1, the insertion-side component 2 and the receiving-side component 11 are joined with the insertion-side portion 4 inserted into the receiving-side portion 13. In Figure 2, the joint between the insertion-side portion 4 and the receiving-side portion 13 is shown by a thin dashed line. Specifically, with the insertion-side portion 4 inserted into the receiving-side portion 13, the opposing surfaces are joined together: the tip surface 7 and the bottom surface 17, the outer peripheral wall 5a and the outer peripheral wall 15a, and the outer peripheral wall 5b and the outer peripheral wall 15b.

[0027] This joining integrates the body portion 3 and the body portion 12 to form a single cylindrical portion. A cylindrical flow-stopping wall portion 18 is connected to the outer circumference of the joint between the insertion portion 4 and the receiving portion 13, spaced apart with a gap g2. The flow-stopping wall portion 18 protrudes axially from the tip surface of the outer peripheral wall 5b, with a protrusion of, for example, 5 mm to 10 mm. A cylindrical inner peripheral wall 16, which functions as a flow-stopping wall, is connected to the inner circumference of the joint between the insertion portion 4 and the receiving portion 13, spaced apart with a gap g1. The amount of axial protrusion from the bottom surface 17 of the inner peripheral wall 16 is, for example, 10 mm to 15 mm. The gaps g1 and g2 are, for example, about 0.5 mm to 2 mm. Note that there is a gap between the tip surface 16a of the inner peripheral wall 16 and the insertion-side component 2 (insertion portion 4).

[0028] The following describes an example of the procedure for manufacturing the silencer 1 using the manufacturing method of the present invention.

[0029] First, the insertion-side component 2 and the receiving-side component 11, as illustrated in Figures 4 and 5, are molded by resin injection molding. The insertion-side component 2 and the receiving-side component 11 can be injection molded using a known injection molding machine and a known method. Therefore, when the insertion-side component 2 and the receiving-side component 11 are injection molded, the circumferential ribs 10a, 10b, 21a, and 21b are also molded integrally at the same time.

[0030] Next, as illustrated in Figures 6 to 8, the insertion part 4 is inserted into the receiving part 13 and fitted into place. More specifically, the receiving part 11 is fixed to the fixed part of the spin welding machine, and the insertion part 2 is fixed to the movable part of the spin welding machine. With their axes CL aligned, the insertion part 2 is moved downward to insert the insertion part 4 into the annular groove 14. Any known spin welding machine may be used.

[0031] Then, the tip surface 7 of the insertion portion 4 is brought into contact with the bottom surface 17 of the annular groove 14 and pressed, and the outer surface of the insertion portion 4 is brought into contact with the outer peripheral walls 15a and 15b of the annular groove 14, while the inner peripheral wall 6 of the insertion portion 4 is kept in a non-contact state with the inner peripheral wall 16 of the annular groove 14 with a gap g1. In addition, the outer surface of the insertion portion 4 and the flow-stopping wall portion 18 are kept in a non-contact state with a gap g2.

[0032] Next, with the receiving part 11 fixed in place, the insertion part 2 is rotated around the axis CL to spin-weld the contact portion between the insertion part 4 and the annular groove 14. That is, the tip surface 7 and the bottom surface 17, the outer peripheral wall 5a and the outer peripheral wall 15a, and the outer peripheral wall 5b and the outer peripheral wall 15b are welded together. As a result, the body 3 of the insertion part 2 and the body 12 of the receiving part 11 are joined together to form a single cylindrical part. Alternatively, the receiving part 11 can be rotated around the axis CL while the insertion part 2 is fixed in place, and the insertion part 2 and the receiving part 11 can be rotated relative to each other around the axis CL to perform spin welding.

[0033] When spin welding, the spin rotation speed and the pressing force (the amount of downward movement of the insertion-side part 2) applied to the tip surface 7 against the bottom surface 17 of the annular groove 14 should be determined through prior testing to determine the appropriate range for successful welding. Then, the spin rotation speed and pressing force should be set within that appropriate range, and spin welding should be performed.

[0034] In this way, the insertion part 2 and the receiving part 11 are joined and integrated by spin welding to produce the silencer 1 illustrated in Figures 1 to 3. A cylindrical flow-stopping wall 18, which protrudes upward and is connected to the outer circumference of the joint portion between the insertion part 4 and the receiving part 13 (tip surface 7 and bottom surface 17, outer circumference side wall 5a and outer circumference side wall 15a, outer circumference side wall 5b and outer circumference side wall 15b) with a gap g2 between them, blocks the flow of molten resin during spin welding. This prevents burrs generated by the solidification of molten resin from protruding onto the outer circumference of the silencer 1 (body parts 3 and 12). In addition, a cylindrical inner circumference side wall 16, which is connected to the inner circumference of this joint portion with a gap g1 between them, also functions as a flow-stopping wall, thus blocking the flow of molten resin during spin welding. This prevents burrs, which are formed when molten resin solidifies, from protruding from the inner surface of the silencer 1 (body sections 3 and 12).

[0035] In other words, burrs generated during joining are contained within gaps g1 and g2 and do not protrude to the outside of the flow-stopping wall 18 or to the inside of the inner peripheral wall 16. Therefore, deburring is unnecessary, and the risk of damage to the joint due to burrs is reduced, which is advantageous for stably and firmly joining the insertion-side component 2 and the receiving-side component 11.

[0036] Furthermore, since the respective body sections 3 and 12 and pipe sections 9 and 20 are connected via the expanded pipe sections 8 and 19, when internal pressure acts on the silencer 1 during use, it is possible to avoid the generation of locally excessive stress in the region between the body section 3 and pipe sections 9 and 20, and in the region between the body section 12 and pipe section 20. Moreover, the circumferential ribs 10a and 21a protruding from the outer circumferential surfaces of the respective body sections 3 and 12 resist the internal pressure acting on the silencer 1. Therefore, it is possible to avoid the generation of locally excessive stress in the respective body sections 3 and 12, the expanded pipe sections 8 and 19, and the joints. Thus, with this silencer 1, sufficient pressure resistance against internal pressure can be ensured despite being made of lightweight resin.

[0037] As illustrated in Figure 2, the refrigerant C flows in from one pipe section 9, passes through the expanded section 8, the body sections 3 and 12, and the expanded section 19, and flows out from the other pipe section 18, thus circulating. In the expanded sections 8 and 19, the refrigerant C flows along the inner surface. In this embodiment, the circulating refrigerant C interferes with the circumferential ribs 10b and 21b that protrude from the inner surface of the body sections 3 and 12, thereby canceling out the noise and pulsation caused by the circulating refrigerant C, and further reducing noise and pulsation.

[0038] As illustrated in Figure 9, it is also possible to have a specification in which circumferential ribs 10b and 21b with different protruding heights are arranged in a line along the axial direction. The circumferential ribs 10b and 21b are not limited to a specification in which they protrude in a direction perpendicular to the axial direction as in the embodiment described above, but can also be made to protrude with an inclination toward one side of the axial direction (towards the pipe section 20).

[0039] As illustrated in Figures 10 and 11, the outer circumferential surfaces of the respective body sections 3 and 12 can also be provided with axial ribs 10c and 21c extending in the axial direction, in addition to the circumferential ribs 10a and 21a. The axial ribs 10c and 21c are molded integrally at the same time when the insertion-side part 2 and the receiving-side part 11 are injection-molded. The axial ribs 10c and 21c are made to be substantially the same.

[0040] The axial ribs 10c and 21c should be positioned at least in the axial center of the body sections 3 and 12, and preferably within the same range as the circumferential ribs 10a and 21a. The protruding height and rib width of the axial ribs 10c and 21c should be the same as those of the circumferential ribs 10a and 21a. Three or more axial ribs 10c and 21c should be positioned at equal intervals in the circumferential direction, preferably between 3 and 12. Furthermore, it is desirable that the circumferential positions of the axial ribs 10c and 21c coincide.

[0041] By incorporating axial ribs 10c and 21c in addition to circumferential ribs 10a and 21a, it becomes advantageous to further improve the durability of the body sections 3 and 12 (silencer 1).

[0042] Instead of the axial ribs 10c and 21c illustrated in Figure 10, the design can also be modified as illustrated in Figure 12, with oblique ribs 10d and 21d protruding from the outer circumferential surface of the body portions 3 and 12, inclined at, for example, 30° to 60° with respect to the axial direction. The oblique ribs 10d and 21d are integrally molded simultaneously when the insertion-side component 2 and the receiving-side component 11 are injection-molded. The oblique ribs 10d and 21d are substantially the same in specifications. The protrusion height and rib width of the oblique ribs 10d and 21d are equivalent to those of the circumferential ribs 10a and 21a.

[0043] The insertion-side component 2 and the receiving-side component 11 can be joined not only by spin welding, but also by other known methods. For example, the insertion-side component 2 and the receiving-side component 11 can be joined and integrated by high-frequency welding, hot plate welding, ultrasonic welding, etc. [Explanation of Symbols]

[0044] 1 Silencer 2 Insertion-side component 3. Body (cylindrical section) 4 Insertion part 5a, 5b Outer peripheral wall 6 Inner peripheral wall 7 Tip surface 8. Pipe expansion section 8a Flow expansion section 9. Pipe section 10a, 10b circumferential ribs 10c Axial Rib 10d Diagonal Ribs 11 Receiving part 12 Body (cylindrical section) 13 Receiving part 14 Circular groove 15a, 15b Outer peripheral wall 16. Inner circumferential wall (flow-stopping wall section) 17. Bottom 18 Flow-stopping wall section 19. Pipe expansion section 20 Pipe section 21a, 21b circumferential ribs 21c Axial Rib 21d Diagonal Ribs C Refrigerant

Claims

1. A method for manufacturing a resin silencer connected to the piping of an automobile air conditioner, An insertion-side component having an annular circumferential rib protruding from the outer surface of a cylindrical body, an insertion portion at one end of the body in the axial direction, and a pipe portion smaller in diameter than the body connected to the other end in the axial direction via an expanded pipe portion that widens toward the body, A cylindrical body has annular circumferential ribs protruding from its outer surface, and the other end of the body in the axial direction has a receiving portion into which the insertion part is inserted. A receiving part is connected to one end of the body in the axial direction via an expanded pipe section that widens toward the body, and both are molded by resin injection molding. The receiving portion has an annular groove into which the cylindrical insertion portion is inserted, and a cylindrical flow-stopping wall portion connected to the outer circumference of the annular groove at a distance from each other. A method for manufacturing a resin silencer, comprising: pressing the tip surface of the insertion part inserted into the annular groove against the bottom surface of the annular groove; bringing the outer surface of the insertion part into contact with the outer peripheral wall of the annular groove; leaving a gap between the inner surface of the insertion part and the inner peripheral wall of the annular groove to create a non-contact state; and rotating the insertion part and the receiving part relative to each other around their axis, thereby spin-welding the contact portion between the insertion part and the annular groove to join the body of the insertion part and the body of the receiving part to form an integrated cylindrical part.

2. A method for manufacturing a resin silencer according to claim 1, wherein an axial rib extending in the axial direction is provided on the outer circumferential surface of the insertion-side component by resin injection molding, and an axial rib extending in the axial direction is provided on the outer circumferential surface of the receiving-side component by resin injection molding.

3. A method for manufacturing a resin silencer according to claim 1 or 2, wherein an annular circumferential rib is provided protruding from the inner circumferential surface of the body of the insertion-side component by resin injection molding, and an annular circumferential rib is provided protruding from the inner circumferential surface of the body of the receiving-side component by resin injection molding.

4. A method for manufacturing a resin silencer according to claim 3, wherein the circumferential ribs protruding from the outer circumferential surface and the circumferential ribs protruding from the inner circumferential surface of the body of the insertion-side component are arranged to be offset in the axial direction, and the circumferential ribs protruding from the outer circumferential surface and the circumferential ribs protruding from the inner circumferential surface of the body of the receiving-side component are arranged to be offset in the axial direction.

5. A resin silencer that connects to the piping of an automobile air conditioner, A resin insert-side component has an annular circumferential rib protruding from the outer surface of a cylindrical body, with an insertion portion at one end of the body in the axial direction, and a pipe portion smaller in diameter than the body connected to the other end in the axial direction via an expanded pipe portion that widens toward the body. A cylindrical body has annular circumferential ribs protruding from its outer surface, and the other end of the body in the axial direction has a receiving portion into which the insertion portion is inserted. The receiving part is made of resin and has a pipe portion with a smaller diameter than the body connected to one end in the axial direction via an expanded pipe portion that widens toward the body. The insertion portion is inserted into the receiving portion and joined together, and the body of the insertion part and the body of the receiving part, which are integrated by this joining, form a cylindrical portion. A resin silencer having a cylindrical flow-stopping wall portion connected at a distance from the outer circumference of the joint between the insertion portion and the receiving portion, and a cylindrical flow-stopping wall portion connected at a distance from the inner circumference of the joint portion.

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