Method for manufacturing an opening member

Abstract

To excellently insert a cover member into an opening.SOLUTION: A manufacturing method includes inserting a cover member attached to a fitting surface of a cover member into a substantially circular opening of an opening member. An inner peripheral part of the cover member is substantially elliptical, and a holding part of the cover member is held by an end part of the opening member and another member connected to the opening. A long diameter of an outer periphery of an inner peripheral part is equal to or larger than a diameter of the opening, and a short diameter of the outer periphery of the inner peripheral part is less than a diameter of the opening. A length of the outer periphery of the inner peripheral part is equal to or less than a length of a circumference of the opening. A first virtual line of the fitting surface shows an inner peripheral part of the cover member, and a second virtual line of the fitting surface shows the opening when inserting the cover member. A positioning part is disposed inside the first and second virtual lines on the fitting surface, and the positioning part is close to a plurality of specific places of the first virtual line.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing an opening member.

Background Art

[0002] Parts used in a turbocharger of a vehicle engine and its surroundings are exposed to high-temperature exhaust gas, so they are required to have high-temperature oxidation resistance, and they are also required to have repeated oxidation resistance because heating and cooling occur repeatedly. In contrast, Patent Document 1 discloses a technique for improving the heat resistance of an exhaust pipe by providing a cover member at an opening of the exhaust pipe into which exhaust gas from the turbocharger flows and covering a portion around the opening on the inner peripheral surface of the exhaust pipe.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The cover member is a ring-shaped member, and includes an inner peripheral portion that covers the inner peripheral surface of the exhaust pipe and a clamping portion that extends outward from an end portion of the inner peripheral portion. First, the cover member is inserted into the opening of the exhaust pipe so that the inner peripheral portion covers the inner peripheral surface of the exhaust pipe. Then, the upstream exhaust pipe is fastened to the opening of the exhaust pipe into which the cover member is inserted by a V-clamp or the like. At this time, the clamping portion of the cover member is clamped by an end surface surrounding the opening of these exhaust pipes.

[0005] In one aspect of the present disclosure, it is desirable to insert the cover member well into the opening.

Means for Solving the Problems

[0006] One aspect of the present disclosure is a method for manufacturing an opening member having a substantially circular opening provided at an end, the method comprising attaching a cover member to an attachment surface of a jig, and inserting the cover member attached to the attachment surface of the jig into the opening. The cover member has an inner peripheral portion and a clamping portion. The inner peripheral portion is a ring-shaped portion that is substantially elliptical, and when the cover member is inserted into the opening, an outer peripheral surface thereof faces an inner peripheral surface that surrounds an internal space of the opening member communicating with the opening. The clamping portion is a portion that extends outward from an end of the inner peripheral portion and is a portion that is clamped between an end of the opening member and another member connected to the opening. A major axis of an outer periphery of the inner peripheral portion is equal to or longer than a diameter of the opening, and a minor axis of the outer periphery of the inner peripheral portion is shorter than the diameter of the opening. A length of an outer periphery of the inner peripheral portion is equal to or less than a circumference length of the opening. First and second virtual lines can be set on the attachment surface, the first virtual line indicates the inner peripheral portion of the cover member attached to the attachment surface, the second virtual line indicates the opening when inserting the cover member attached to the attachment surface, and a center of the inner peripheral portion indicated by the first virtual line and a center of the opening indicated by the second virtual line substantially coincide with each other. A positioning portion is provided inside the first and second virtual lines on the attachment surface, the positioning portion is close to a plurality of specific locations on the first virtual line, and at least two of the plurality of specific locations face each other with the center of the first virtual line and the center of the second virtual line interposed therebetween.

[0007] According to the above configuration, when attaching the cover member to the attachment surface of the jig, the cover member can be appropriately positioned by the positioning portion. Further, since the positioning portion is located inside the second virtual line, it is possible to suppress the positioning portion from interfering with the insertion of the cover member into the opening of the opening member using the jig. For this reason, the cover member can be satisfactorily inserted into the opening.

[0008] In one aspect of the present disclosure, the plurality of specific locations may be located around at least three intersections of the first virtual line and the second virtual line. According to the above configuration, the positioning of the cover member when attaching the cover member to the attachment surface of the jig can be appropriately performed.

[0009] In one aspect of the present disclosure, the positioning portion may have two long portions extending along the major axis direction of the inner peripheral portion of the substantially elliptical shape indicated by the first virtual line, and two short portions extending along the minor axis direction.

[0010] According to the above configuration, the positioning of the cover member when attaching the cover member to the attachment surface of the jig can be appropriately performed. In one aspect of the present disclosure, the opening member may be an exhaust pipe mounted on a vehicle.

[0011] According to the above configuration, the cover member can be favorably inserted into the opening of the exhaust pipe.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Mode for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the embodiments of the present disclosure are not limited to the following embodiments, and various forms can be adopted as long as they belong to the technical scope of the present disclosure.

[0014] [1. First exhaust pipe] The first exhaust pipe 1 constitutes a flow path for exhaust gas from the engine of the vehicle (see FIG. 1). As an example, the first exhaust pipe 1 is fastened by a V clamp 5 on the downstream side of a second exhaust pipe 3 (in other words, another member) that discharges exhaust gas from the turbocharger. Further, the first exhaust pipe 1 is configured to accommodate a purification member (for example, a catalyst or a filter) that purifies exhaust gas.

[0015] The first and second exhaust pipes 1 and 3 may be made of an austenitic steel material having heat resistance, for example. However, the first and second exhaust pipes 1 and 3 are not limited to an austenitic steel material, and may be made of other steel materials having heat resistance. Further, the second exhaust pipe 3 may be made of a material having higher heat resistance than the material constituting the first exhaust pipe 1.

[0016] The first exhaust pipe 1 includes a first end portion 10, a first opening 11, a first flange portion 12, and a cover member 2 described later (see FIGS. 1 to 3). The first opening 11 is a substantially circular opening located at the first end portion 10 of the first exhaust pipe 1 and communicates with the internal space 16 of the first exhaust pipe 1. The first opening 11 is located on the upstream side in the exhaust gas flow direction in the first exhaust pipe 1 and is connected to the second exhaust pipe 3. Hereinafter, a straight line passing through the center of the first opening 11 and orthogonal to the first opening 11 is described as the axis 11A.

[0017] The first flange portion 12 is provided at the first end portion 10 of the first exhaust pipe 1 and is used for fastening with the second exhaust pipe 3. The first end portion 10 surrounds the first opening 11 and extends planar in a direction orthogonal to the axis 11A of the first opening 11. The first end portion 10 includes a groove portion 13 and a first edge portion 14.

[0018] The first edge portion 14 is a portion that protrudes from the first end portion 10 toward the second exhaust pipe 3 along the axis 11A, is adjacent to the first opening 11, and surrounds the first opening 11. The clamping surface 14A located at the top of the first edge portion 14 extends planar in a direction orthogonal to the axis 11A. Further, the inner peripheral surface of the first edge portion 14 forms an inner peripheral surface 15 that surrounds the internal space 16 in the first exhaust pipe 1.

[0019] Also, a chamfered portion 14C is formed at the boundary between the clamping surface 14A and the inner peripheral surface 15 in the first edge portion 14 (see FIG. 2). The chamfered portion 14C is formed so as to surround the first opening 11 and is inclined so as to move away from the axis 11A as it goes toward the first end portion 10 side. The chamfered portion 14C is inclined with respect to the axis 11A by, for example, 10 to 80 degrees, more preferably 45 degrees.

[0020] The groove portion 13 is a groove-shaped portion provided at the first end portion 10 and surrounds the first opening 11. The groove portion 13 is provided adjacent to the outside of the first edge portion 14, and the outer peripheral surface 14B of the first edge portion 14 protrudes from the bottom surface of the groove portion 13 along the axis 11A. A ring-shaped gasket 4 is disposed in the groove portion 13 to seal the gap between the first opening 11 and the second opening 31.

[0021] [2. Second Exhaust Pipe] The second exhaust pipe 3 includes a second end portion 30, a second opening 31, and a second flange portion 32 (see FIGS. 1 and 2).

[0022] The second opening 31 is located at the second end portion 30 of the second exhaust pipe 3. Also, the second opening 31 is connected to the first opening 11 of the first exhaust pipe 1, and its shape is the same as that of the first opening 11 (for example, substantially circular).

[0023] The second flange portion 32 is provided at the second end portion 30 of the second exhaust pipe 3 and is used for fastening to the first exhaust pipe 1. The second end portion 30 surrounds the second opening 31 and extends planar in a direction orthogonal to the axis 11A of the first opening 11 of the first exhaust pipe 1 connected to the second opening 31. The second end portion 30 includes a recessed portion 33.

[0024] The recessed portion 33 is formed at the second end portion 30 adjacent to and surrounding the second opening 31, and has a bottom surface 34 and a first inner peripheral surface 35. The bottom surface 34 is a portion that extends planar in a direction orthogonal to the axis 10A of the first opening 11 connected to the second opening 31, and is provided so as to go around the inner peripheral surface of the second exhaust pipe 3. Also, the bottom surface 34 forms a step on the inner peripheral surface of the second exhaust pipe 3, and divides the inner peripheral surface into a first inner peripheral surface 35 and a second inner peripheral surface 36.

[0025] The first inner peripheral surface 35 is adjacent to and surrounds the second opening 31. Also, the first inner peripheral surface 35 is adjacent to the second inner peripheral surface 36 with the bottom surface 34 in between, and the diameter of the first inner peripheral surface 35 is larger than the diameter of the second inner peripheral surface 36.

[0026] [3. Cover member] The cover member 2 is provided at the first end portion 10 of the first exhaust pipe 1 and is sandwiched by the fastened first end portion 10 and the second end portion 30 of the second exhaust pipe 3 (see FIGS. 1 to 3). The cover member 2 is a ring-shaped member provided so as to surround the first opening 11, and includes a clamping portion 20 and an inner peripheral portion 21, and the cross-section orthogonal to the circumferential direction is L-shaped.

[0027] The inner peripheral portion 21 is a flat ring-shaped member, and the width direction of the inner peripheral portion 21 substantially coincides with the direction orthogonal to the radial direction of the cover member 2. The outer peripheral surface 21B of the inner peripheral portion 21 faces the portion around the first opening 11 on the inner peripheral surface 15 of the first exhaust pipe 1. Specifically, the outer peripheral surface 21B of the inner peripheral portion 21 is in contact with this portion or is arranged with a gap therebetween.

[0028] The clamping portion 20 is also a flat ring-shaped member, and the width direction of the clamping portion 20 substantially coincides with the radial direction of the cover member 2. The clamping portion 20 extends outward from the end portion in the width direction of the inner peripheral portion 21. The clamping portion 20 is clamped by the clamping surface 14A of the first edge portion 14 of the first exhaust pipe 1 and the bottom surface 34 of the recessed portion 33 of the second exhaust pipe 3.

[0029] The cover member 2 is made of a material having higher heat resistance than the material constituting the first end portion 10 etc. of the first exhaust pipe 1. Specifically, the cover member 2 may be made of, for example, a ferritic steel material. Of course, the cover member 2 may be made of other materials. Also, the heat resistance of the material constituting the cover member 2 may be the same as or lower than the heat resistance of the material constituting the first end portion 10 etc. of the first exhaust pipe 1.

[0030] [4. Mounting of Cover Member] Next, a method of mounting the cover member 2 to the first end portion 10 of the first exhaust pipe 1, in other words, a method of manufacturing the first exhaust pipe 1 with the cover member 2 mounted on the first end portion 10 will be described.

[0031] [(1) Cover Member Before and After Mounting] The cover member 2 before being mounted on the first end portion 10 is in a substantially elliptical ring shape (see FIG. 4). Specifically, the major axis DL of the substantially ellipse formed by the outer peripheral surface 21B of the inner peripheral portion 21 is larger than the diameter D of the first opening 11, and the minor axis DS of the substantially ellipse is less than the diameter D of the first opening 11. Note that the major axis DL may be equal to the diameter D. Also, the circumference of the substantially ellipse, that is, the circumferential length of the outer peripheral surface 21B is shorter than the circumferential length of the first opening 11.

[0032] The attachment of the cover member 2 to the first end portion 10 is performed by a plurality of steps including an attachment step and an insertion step. Then, the cover member 2 attached to the first end portion 10 is arranged along the circumference of the first opening 11 in a state where elastic deformation has occurred, and the shape of the cover member 2 becomes substantially circular or substantially elliptical with the major diameter DL shortened and the minor diameter DS extended. Therefore, the elastic force of the cover member 2 promotes the position of the cover member 2 to be held.

[0033] Therefore, when the cover member 2 attached to the first end portion 10 becomes substantially elliptical, the outer peripheral surface 21B of the inner peripheral portion 21 in the major diameter portion 2A of the cover member 2 after attachment abuts against the inner peripheral surface 15 of the first exhaust pipe 1. On the other hand, the outer peripheral surface 21B in the minor diameter portion 2B of the cover member 2 is arranged with a gap from the inner peripheral surface 15 of the first exhaust pipe 1.

[0034] Note that the major diameter portion 2A means a portion located around the end of the major diameter DL in the cover member 2 before attachment to the first end portion 10. The portion corresponding to the major diameter portion 2A of the cover member 2 before attachment in the cover member 2 after attachment to the first end portion 10 is also referred to as the major diameter portion 2A. Further, the minor diameter portion 2B means a portion located around the end of the minor diameter DS in the cover member 2 before attachment to the first end portion 10. The portion corresponding to the minor diameter portion 2B of the cover member 2 before attachment in the cover member 2 after attachment to the first end portion 10 is also referred to as the minor diameter portion 2B.

[0035] [(2) Pushing jig] When attaching the cover member 2, a pushing jig 6 is used (see FIGS. 5 to 7). The pushing jig 6 includes a columnar base portion 60, a rectangular thick plate-shaped bottom portion 61, and a positioning portion 63 (in other words, a mandrel).

[0036] On the outer surface of the bottom portion 61, first and second square surfaces facing each other in the thickness direction are formed. The base portion 60 is provided so as to protrude from the first surface of the bottom portion 61. On the other hand, the second surface of the bottom portion 61 is configured as an attachment surface 62 to which the cover member 2 can be attached. As an example, the cover member 2 is attached to the attachment surface 62 by a magnetic force of a magnet disposed inside the bottom portion 61. At this time, the surface of the sandwiching portion 20 of the cover member 2 that abuts on the second end portion 30 of the second exhaust pipe 3 abuts on the attachment surface 62, and the inner peripheral portion 21 protrudes from the attachment surface 62. Of course, the cover member 2 can be attached to the attachment surface 62 by various methods such as fastening and adhesion, not limited to the magnetic force.

[0037] The positioning portion 63 is a portion for positioning the cover member 2 attached to the attachment surface 62. The positioning portion 63 is provided so as to protrude from the attachment surface 62 of the bottom portion 61, and the cover member 2 is attached to the attachment surface 62 in a state where the positioning portion 63 is positioned inside the inner peripheral portion 21.

[0038] Here, first and second virtual lines 64 and 65 can be set on the attachment surface 62 (see FIGS. 8, 111 to 17). The first virtual line 64 indicates the inner peripheral portion 21 of the cover member 2 attached to the attachment surface 62. The second virtual line 65 indicates the circumference of the first opening 11 when the cover member 2 attached to the attachment surface 62 is inserted. That is, the first virtual line 64 is substantially elliptical, the second virtual line 65 is substantially circular, and the center of the inner peripheral portion 21 indicated by the first virtual line 64 and the center of the first opening 11 indicated by the second virtual line 65 substantially coincide.

[0039] Note that, as an example, the first and second virtual lines 64 and 65 mean virtual lines that are not actually provided on the attachment surface 62. However, the first and second virtual lines 64 and 65 may be lines actually provided on the attachment surface 62, and the first and second virtual lines 64 and 65 may be drawn on the attachment surface 62, for example.

[0040] And the positioning portion 63 is provided in the region inside the first and second virtual lines 64, 65 on the mounting surface 62 and is close to at least two specific locations 64A on the first virtual line 64. In the present disclosure, "close" is a concept that includes contact. That is, the positioning portion 63 close to the specific location 64A has a slight gap with respect to the specific location 64A or is in contact with the specific location 64A. The two specific locations 64A face each other with the centers of the first virtual line 64 and the second virtual line 65 interposed therebetween.

[0041] As an example, the positioning portion 63 is provided in a substantially rectangular region on the mounting surface 62 (see FIG. 8). That is, when viewed from the front of the mounting surface 62, the positioning portion 63 has a substantially rectangular shape. And at the edge of the positioning portion 63, there are formed two long portions 63A extending substantially linearly along the major axis DL direction of the outer peripheral surface 21B of the inner peripheral portion 21 indicated by the first virtual line 64, and two short portions 63B extending substantially linearly along the minor axis DS direction of the outer peripheral surface 21B. Hereinafter, the major axis DL and the minor axis DS of the outer peripheral surface 21B of the inner peripheral portion 21 indicated by the first virtual line 64 may be simply referred to as the major axis DL and the minor axis DS, respectively.

[0042] Also, the four corner portions of the positioning portion 63 each have a roundness and are close to the first virtual line 64 around the four intersection points of the first virtual line 64 and the second virtual line 65 (hereinafter, virtual intersection points 64B). That is, the four locations close to these corner portions on the first virtual line 64 become the specific locations 64A, and these specific locations 64A are located around the four virtual intersection points 64B. Also, each specific location 64A faces another specific location 64A with the centers of the first and second virtual lines 64, 65 (hereinafter, virtual center 64C) interposed therebetween.

[0043] [(3) Mounting process and insertion process] In the mounting process, the cover member 2 is mounted on the mounting surface 62 so as to surround the positioning portion 63 in a state where the major axis DL direction coincides with the direction of the long portion 63A of the positioning portion 63 (see FIGS. 5, 7, and 8). At this time, the four corners of the positioning portion 63 are close to the inner peripheral surface 21A of the inner peripheral portion 21 of the cover member 2. Thereby, the inner peripheral portion 21 of the cover member 2 is arranged along the first imaginary line 64.

[0044] In the subsequent insertion process, first, the first exhaust pipe 1 is fixed by a fixing jig (not shown) provided around the first end portion 10 of the first exhaust pipe 1. Then, with the cover member 2 attached to the mounting surface 62 of the pressing jig 6 arranged at an insertion position determined with reference to the first exhaust pipe 1 (for example, the first opening 11), for example, in a state where the virtual center 64C and the axis 11A coincide, the cover member 2 is brought close to the first opening 11 and inserted into the first opening 11 (see FIG. 7).

[0045] When the cover member 2 is inserted into the first opening 11, the cover member 2 arranged along the first imaginary line 64 is deformed into a substantially circular shape and extends along the second imaginary line 65 of the mounting surface 62. After insertion, by moving the pressing jig 6 away from the first opening 11, the cover member 2 is separated from the mounting surface 62 while remaining inserted into the first opening 11, whereby the mounting of the cover member 2 is completed.

[0046] Also, during the insertion of the cover member 2, the end portion of the inner peripheral portion 21 in the major axis portion 2A of the cover member 2 collides with the chamfered portion 14C of the first exhaust pipe 1 (see FIG. 9). Then, while the inner peripheral portion 21 is deformed so as to incline inward due to the inclination of the chamfered portion 14C, it enters the first opening 11. On the other hand, the inner peripheral portion 21 in the minor axis 2B is located inside the chamfered portion 14C of the first exhaust pipe 1, and the end portion of the inner peripheral portion 21 does not collide with the clamping surface 14A or the chamfered portion 14C and enters the first opening 11 (see FIG. 10).

[0047] For example, the cover member 2 may be disposed at the insertion position by adjusting the relative position between a mark (not shown) provided on the pressing jig 6 and a specific portion of the first exhaust pipe 1. Further, as an example, the cover member 2 may be press-fitted into the first opening 11 by pressing the pressing jig 6 toward the first opening 11.

[0048] Further, by inserting the cover member 2 at the insertion position into the first opening 11, the inner peripheral portion 21 located in the major diameter portion 2A of the cover member 2 is disposed at a portion (hereinafter referred to as the vulnerable portion) of the inner peripheral surface 15 of the first exhaust pipe 1 where damage is likely to occur. Thereby, the inner peripheral portion 21 of the cover member 2 attached to the first opening 11 is urged to abut against the vulnerable portion, and it is possible to suppress the exhaust gas from directly hitting the vulnerable portion. Specifically, for example, a portion where the flow of the deflected exhaust gas tends to concentrate or a portion that tends to become relatively hot may be used as the vulnerable portion. Also, if a waste gate is provided inside the second exhaust pipe 3, a portion where the flow of the exhaust gas flowing out from the waste gate concentrates may be used as the vulnerable portion. In addition to this, for example, a portion of the first exhaust pipe 1 having a thin wall thickness and low strength or a portion where stress is likely to concentrate may be used as the vulnerable portion. Further, for example, it is assumed that a positioning portion including a concave portion or a convex portion or the like is provided at a part in the circumferential direction of the cover member 2. In this case, it is conceivable to provide a to-be-positioned portion including a convex portion or a concave portion at an edge portion of the first opening 11 of the first exhaust pipe 1 corresponding to the circumferential positioning portion. In such a case, the to-be-positioned portion becomes the vulnerable portion.

[0049] On the other hand, the inner peripheral portion 21 located in the minor diameter portion 2B of the cover member 2 comes into contact with the inner peripheral surface 15 of the first exhaust pipe 1 or has a gap with respect to the inner peripheral surface 15. Thereafter, for example, the first end portion 10 of the first exhaust pipe 1 to which the cover member 2 is attached and the second end portion 30 of the second exhaust pipe 3 are fastened by a V clamp 5 or the like.

[0050] [5. Modification Example of Positioning Portion] [(1) Modification Example 1] As shown in FIG. 11, the positioning portion 63 of the above embodiment may be provided in a substantially rectangular region where the long side and the short side are curved in an arc shape so that the center thereof bulges outward. That is, the positioning portion 63 is substantially rectangular, but each long portion 63A and each short portion 63B are arc-shaped. And the entire area of each long portion 63A extends along the major axis DL in the first virtual line 64 and is close to each of the two sections facing each other across the virtual center 64C. That is, these two sections become the specific location 64A. Further, these specific locations 64A are located around the four virtual intersection points 64B. Note that a part of each long portion 63A may be close to this section. On the other hand, each short portion 63B is located at a position away from the first and second virtual lines 64 and 65.

[0051] And in the mounting process, with the direction of the major axis DL substantially coinciding with the direction of the long portion 63A of the positioning portion 63, the cover member 2 is mounted on the mounting surface 62 so as to surround the positioning portion 63. At this time, each long portion 63A is close to the inner peripheral surface 21A of the inner peripheral portion 21 located in the section including the minor diameter portion 2B of the cover member 2. Thereby, the inner peripheral portion 21 of the cover member 2 is arranged along the first virtual line 64.

[0052] [(2) Modification 2] As shown in FIG. 12, the positioning portion 63 may be provided in a substantially elliptical region where the major axis and the minor axis directions coincide with the major axis DL and the minor axis DS directions of the first virtual line 64, respectively. At the edge of the positioning portion 63, two long portions 63A passing through the end of the minor axis and extending along the major axis DL direction of the first virtual line 64, and two short portions 63B passing through the end of the major axis and extending along the minor axis DS direction of the first virtual line 64 are provided. And each long portion 63A is close to each of the two sections passing through the end of the minor axis DS in the first virtual line 64 and facing each other across the virtual center 64C. That is, these two sections become the specific location 64A. On the other hand, each short portion 63B is located at a position away from the first and second virtual lines 64 and 65.

[0053] In the mounting process, the cover member 2 is mounted on the mounting surface 62 in a state where the major axis DL direction substantially coincides with the major axis direction of the positioning portion 63. At this time, each long portion 63A approaches the inner peripheral surface 21A of the inner peripheral portion 21 located in the minor axis portion 2B of the cover member 2. Thereby, the inner peripheral portion 21 of the cover member 2 is arranged along the first virtual line 64.

[0054] [(3) Modification Example 3] As shown in FIG. 13, the positioning portion 63 may be provided in a substantially elliptical region corresponding to the entire inside of the first and second virtual lines 64 and 65. That is, each long portion 63A extending along the major axis at the edge of the positioning portion 63 is located inside the second virtual line 65 on the first virtual line 64 and approaches the entire area of each of the two sections facing each other with the virtual center 64C interposed therebetween. That is, these two sections become the specific locations 64A. Further, these specific locations 64A are located around the four virtual intersection points 64B. Note that a part of each long portion 63A may be close to this section.

[0055] In addition, the two short portions 63B, which are portions extending along the minor axis at the edge of the positioning portion 63, respectively approach the entire area of each of the two sections located inside the first virtual line 64 on the second virtual line 65. Further, an elastic portion 63C is provided in the positioning portion 63 corresponding to each short portion 63B. The elastic portion 63C is configured to displace the short portion 63B toward the center side of the positioning portion 63 along the major axis direction in response to an external pressing force and return to the original position by an elastic force. Specifically, the elastic portion 63C may be, for example, a portion formed of an elastic material provided around the short portion 63B in the positioning portion 63, or a portion having a spring or the like disposed inside the positioning portion 63.

[0056] Then, in the mounting step, with the major axis DL direction substantially coinciding with the direction of the long portion 63A, the cover member 2 is mounted on the mounting surface 62 so as to surround the positioning portion 63. At this time, each long portion 63A is close to the inner peripheral surface 21A of the inner peripheral portion 21 located in the section including the minor diameter portion 2B of the cover member 2. Thereby, the inner peripheral portion 21 of the cover member 2 is arranged along the first imaginary line 64.

[0057] Also, when the cover member 2 is inserted into the first opening 11 in the insertion step, the cover member 2 is deformed, and the cover member 2 is in a state of extending along the second imaginary line 65 of the mounting surface 62. Each short portion 63B of the positioning portion 63 is close to the cover member 2 after insertion. At this time, by deforming each short portion 63B toward the center by the elastic portion 63C, it becomes easier to separate the cover member 2 from the mounting surface 62.

[0058] [(4) Modification Example 4] As shown in FIG. 14, the positioning portion 63 may be provided in a substantially right-angled triangular region on the mounting surface 62. That is, when viewed from the front of the mounting surface 62, the positioning portion 63 is substantially right-angled triangular. And at the edge of the positioning portion 63, a long portion 63A extending substantially linearly along the major axis DL direction of the first imaginary line 64 and a short portion 63B extending substantially linearly along the minor axis DS direction are formed.

[0059] Also, the three corner portions of the positioning portion 63 each have a roundness and are close to the first imaginary line 64 around different virtual intersection points 64B. That is, three locations close to these corner portions on the first imaginary line 64 become specific locations 64A, and these specific locations 64A are located around the three virtual intersection points 64B. Also, two of these specific locations 64A face each other along the portion forming the hypotenuse (hereinafter, hypotenuse portion 63D) of the positioning portion 63 with the virtual center 64C interposed therebetween.

[0060] And in the mounting step, the cover member 2 is mounted on the mounting surface 62 such that the three corner portions of the positioning portion 63 are close to the inner peripheral surface 21A of the inner peripheral portion 21 of the cover member 2. Thereby, the inner peripheral portion 21 of the cover member 2 is arranged along the first virtual line 64.

[0061] [(5) Modification Example 5] As shown in FIG. 15, the positioning portion 63 of the modification example 4 may be provided in a substantially right-angled triangular region in which each side is curved in an arc shape so that the center bulges outward. That is, the positioning portion 63 is a substantially right-angled triangle, but the long side portion 63A, the short side portion 63B, and the hypotenuse portion 63D are in an arc shape.

[0062] And the entire area of the long side portion 63A is close to one of the two sections extending along the major axis DL of the first virtual line 64. That is, the section of the first virtual line 64 becomes the specific location 64A. Note that a part of each long side portion 63A may be close to the section. Also, the corner portion located between the short side portion 63B and the hypotenuse portion 63D is close to the first virtual line 64. That is, two locations on the first virtual line 64 that are close to the long side portion 63A and the corner portion become the specific location 64A. These specific locations 64A are located around the three virtual intersection points 64B. Also, the specific location 64A close to the corner portion faces the end portion of the specific location 64A close to the long side portion 63A with the virtual center 64C interposed therebetween. On the other hand, the short side portion 63B and the hypotenuse portion 63D are located at positions away from the first and second virtual lines 64, 65.

[0063] And in the mounting step, the cover member 2 is mounted on the mounting surface 62 so as to surround the positioning portion 63 in a state where the direction of the major axis DL substantially coincides with the direction of the long side portion 63A of the positioning portion 63. At this time, the long side portion 63A and the corner portion between the short side portion 63B and the hypotenuse portion 63D are close to the inner peripheral surface 21A of the inner peripheral portion 21 located in the section including the minor axis portion 2B of the cover member 2. Thereby, the inner peripheral portion 21 of the cover member 2 is arranged along the first virtual line 64.

[0064] [(6) Modification Example 6] As shown in FIG. 16, the positioning portion 63 may have four portions provided in four substantially circular regions on the mounting surface 62. That is, each portion of the positioning portion 63 is substantially circular when viewed from the front of the mounting surface 62.

[0065] Each portion of the positioning portion 63 (hereinafter, circular portion) is close to the virtual intersection 64B and the first virtual line 64. That is, four locations on the first virtual line 64 close to these circular portions become the specific locations 64A, and these specific locations 64A are respectively located around the four virtual intersections 64B. Also, each specific location 64A faces another specific location 64A with the virtual center 64C in between.

[0066] And in the mounting process, the cover member 2 is mounted on the mounting surface 62 so that the four circular portions of the positioning portion 63 are close to the inner peripheral surface 21A of the inner peripheral portion 21 of the cover member 2. Thereby, the inner peripheral portion 21 of the cover member 2 is arranged along the first virtual line 64.

[0067] Note that the number of circular portions in Modification 6 may be three as shown in FIG. 17, or may be two. When the number of circular portions is two, these circular portions are arranged to face each other with the virtual center 64C in between. That is, the specific locations 64A on the first virtual line 64 where these circular portions are close are arranged with the virtual center 64C in between.

[0068] Also, the number of circular portions may be five or more. In this case, four circular portions are arranged as in FIG. 16, and further circular portions may be provided so as to be close to the first virtual line 64 between the circular portions arranged along the major axis DL.

[0069] [6. Effects] (1) According to the above embodiment, when attaching the cover member 2 to the attachment surface 62 of the pressing jig 6 in the attachment step, by arranging the cover member 2 so as to surround the positioning portion 63, the cover member 2 can be attached to the attachment surface 62 along the first virtual line 64. Therefore, the positioning of the cover member 2 can be appropriately performed. Further, since the positioning portion 63 is located inside the second virtual line 65 indicating the first opening 11 of the first exhaust pipe 1, in the insertion step, it is possible to suppress the positioning portion 63 from interfering with the insertion of the cover member 2 into the first opening 11. Therefore, the cover member 2 can be satisfactorily inserted into the first opening 11.

[0070] (2) Also, around the major axis portion 2A of the elliptical cover member 2, the inner peripheral portion 21 is likely to come into contact with the inner peripheral surface 15 of the first exhaust pipe 1, but around the minor axis portion 2B, there is a possibility that a gap may be generated between the inner peripheral portion 21 and the inner peripheral surface 15 of the first exhaust pipe 1. On the other hand, on the downstream side of the turbocharger, uneven flow of the exhaust gas is likely to occur. For this reason, if the flow of the high-temperature exhaust gas concentrates around the minor axis portion 2B of the cover member 2, the exhaust gas may directly hit the inner peripheral surface 15 of the first exhaust pipe 1, causing damage. Therefore, when inserting the cover member 2 into the first opening 11, it is desirable to adjust the orientation of the cover member 2 so that the periphery of the major axis portion 2A of the cover member 2 covers the portion where the flow of the exhaust gas concentrates.

[0071] On the contrary, according to the above embodiment, by using the positioning portion 63 to arrange the cover member 2 at an appropriate position on the attachment surface 62, in the insertion step, by adjusting the relative position of the pressing jig 6 and the first exhaust pipe 1, the cover member 2 can be surely arranged at the insertion position. As a result, when inserting the cover member 2 into the first opening 11, it is possible to promote the peripheral portion of the major axis portion 2A of the inner peripheral portion 21 to come into contact with the chamfered portion 14C, or to promote it to be arranged at a vulnerable portion on the inner peripheral surface 15 of the first exhaust pipe 1.

[0072] (3) Also, in the above-described embodiment and Modifications 1, 3 to 6, the specific portion 64A is located around at least three virtual intersection points 64B. Thereby, by arranging the cover member 2 so as to surround the positioning portion 63, the cover member 2 is easily arranged along the first virtual line 64. Therefore, the positioning of the cover member 2 can be appropriately performed.

[0073] (4) Also, in the above-described embodiment and Modifications 1 and 3, the positioning portion 63 has two long portions 63A and two short portions 63B. Thereby, it becomes easy to grasp the appropriate attachment position of the cover member 2 based on the positioning portion 63, and by arranging the cover member 2 so as to surround the positioning portion 63, the cover member 2 can be more reliably arranged along the first virtual line 64. Therefore, the positioning of the cover member 2 can be appropriately performed.

[0074] [7. Other Embodiments] (1) The groove portion 13 may not be formed at the first end portion 10 of the first exhaust pipe 1 of the above-described embodiment. Further, the groove portion 13 and the first edge portion 14 may not be formed at the first end portion 10, and the first and second end portions 10 and 30 may be formed as a flat surface without a step. Even in such a case, in the same manner as the above-described embodiment, the cover member 2 can be attached to the first end surface 10, and the sandwiching portion 20 of the cover member 2 can be sandwiched at the first and second end portions 10 and 30.

[0075] (2) In the above-described embodiment, the cover member 2 is attached to the first opening 11 of the first end portion 10 located on the upstream side of the first exhaust pipe 1 connected to the downstream side of the second exhaust pipe 3 that discharges the exhaust gas from the turbocharger. However, it is not limited to this, and the cover member 2 may be attached to the opening at the downstream end portion of the first exhaust pipe 1, or the cover member 2 may be similarly attached to an exhaust pipe arranged away from the turbocharger or an exhaust pipe forming an exhaust gas flow path in which no turbocharger is provided.

[0076] Furthermore, the cover member 2 may be similarly attached to an opening of a tubular member mounted on the vehicle, or an opening of an exhaust pipe not mounted on the vehicle or a tubular member other than the exhaust pipe. Further, not limited to the tubular member, the cover member 2 may be similarly attached to an opening in an opening member having an internal space, an opening communicating with the internal space on the outer surface, and an end portion surrounding the opening.

[0077] (3) A plurality of functions of one component in the above embodiment may be realized by a plurality of components, or one function of one component may be realized by a plurality of components. Further, a plurality of functions of a plurality of components may be realized by one component, or one function realized by a plurality of components may be realized by one component. Further, a part of the configuration of the above embodiment may be omitted. Further, at least a part of the configuration of the above embodiment may be added to or replaced with the configuration of another of the above embodiments.

[0078] [8. Technical idea disclosed in this specification] [Item 1] A method for manufacturing an opening member having a substantially circular opening provided at an end, attaching a cover member to the mounting surface of a jig, inserting the cover member attached to the mounting surface of the jig into the opening, comprising: The cover member is a ring-shaped portion that is substantially elliptical, and when the cover member is inserted into the opening, an inner peripheral portion that is a portion where an outer peripheral surface thereof faces an inner peripheral surface surrounding an internal space of the opening member communicating with the opening, and a portion that extends outward from an end of the inner peripheral portion and is a portion sandwiched between the end portion of the opening member and another member connected to the opening, a major axis of an outer periphery of the inner peripheral portion is equal to or longer than a diameter of the opening, a minor axis of an outer periphery of the inner peripheral portion is shorter than the diameter of the opening, The length of the outer periphery of the inner peripheral portion is equal to or less than the length of the circumference of the opening. On the mounting surface, first and second virtual lines can be set. The first virtual line indicates the inner peripheral portion of the cover member attached to the mounting surface, and the second virtual line indicates the opening when inserting the cover member attached to the mounting surface. The center of the inner peripheral portion indicated by the first virtual line and the center of the opening indicated by the second virtual line substantially coincide. A positioning portion is provided inside the first and second virtual lines on the mounting surface. The positioning portion is close to a plurality of specific locations on the first virtual line, and at least two of the plurality of specific locations face each other with the center of the first virtual line and the center of the second virtual line in between. Method for manufacturing an opening member.

[0079] [Item 2] The method for manufacturing an opening member according to Item 1, The plurality of specific locations are located around at least three intersections of the first virtual line and the second virtual line. Method for manufacturing an opening member.

[0080] [Item 3] The method for manufacturing an opening member according to Item 1 or Item 2, The positioning portion has two long portions extending along the major axis direction of the substantially elliptical inner peripheral portion indicated by the first virtual line and two short portions extending along the minor axis direction. Method for manufacturing an opening member.

[0081] [Item 4] The method for manufacturing an opening member according to any one of Items 1 to 3, The opening member is an exhaust pipe mounted on a vehicle. Method for manufacturing an opening member.

Explanation of Reference Numerals

[0082] 1…First exhaust pipe, 10…First end portion, 11…First opening, 11A…Axis line, D…Diameter, 12…First flange portion, 13…Groove portion, 14…First edge portion, 14A…Clamping surface, 14B…Outer peripheral surface, 14C…Chamfered portion, 15…Inner peripheral surface, 16…Internal space, 2…Cover member, 2A…Long diameter portion, 2B…Short diameter portion, 20…Clamping portion, 21…Inner peripheral portion, 21A…Inner peripheral surface, 21B…Outer peripheral surface, DL…Long diameter, DS…Short diameter, 6…Pressing jig, 60…Base portion, 61…Bottom portion, 62…Mounting surface, 63…Positioning portion, 63A…Long hand portion, 63B…Short hand portion, 63C…Elastic portion, 63D…Hypotenuse portion, 64…First imaginary line, 64A…Specific location, 64B…Imaginary intersection point, 64C…Imaginary center, 65…Second imaginary line.

Claims

1. A method for manufacturing an opening member having a substantially circular opening provided at an end portion, comprising: attaching a cover member to an attachment surface of a jig; inserting the cover member attached to the attachment surface of the jig into the opening; The cover member is: A ring-shaped portion that is substantially elliptical, and when the cover member is inserted into the opening, an inner peripheral portion that is a portion where an outer peripheral surface thereof faces an inner peripheral surface surrounding an inner space of the opening member communicating with the opening; A portion that extends outward from an end of the inner peripheral portion and is a portion sandwiched between the end portion of the opening member and another member connected to the opening, and has a sandwiching portion; The major axis of the outer periphery of the inner peripheral portion is equal to or longer than the diameter of the opening; The minor axis of the outer periphery of the inner peripheral portion is shorter than the diameter of the opening; The length of the outer periphery of the inner peripheral portion is equal to or less than the circumference of the opening; On the attachment surface, first and second virtual lines can be set. The first virtual line indicates the inner peripheral portion of the cover member attached to the attachment surface, and the second virtual line indicates the opening when the cover member attached to the attachment surface is inserted. The center of the inner peripheral portion indicated by the first virtual line and the center of the opening indicated by the second virtual line substantially coincide; A positioning portion is provided inside the first and second virtual lines on the attachment surface. The positioning portion is close to a plurality of specific locations on the first virtual line, and at least two of the plurality of specific locations face each other with the center of the first virtual line and the center of the second virtual line interposed therebetween. A method for manufacturing an opening member.

2. The method for manufacturing an opening member according to claim 1, wherein The plurality of specific locations are located around at least three intersections of the first virtual line and the second virtual line. A method for manufacturing an opening member.

3. The method for manufacturing an opening member according to claim 1 or claim 2, wherein The positioning portion has two long portions extending along the major axis direction of the substantially elliptical inner peripheral portion indicated by the first virtual line and two short portions extending along the minor axis direction. A method for manufacturing an opening member.

4. The method for manufacturing an opening member according to claim 1 or claim 2, wherein The opening member is an exhaust pipe mounted on a vehicle. A method for manufacturing an opening member. ​

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