JP2018183808A - Manufacturing method of collecting pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a collecting pipe for improving weld quality when welding downstream-side parts of a plurality of branch pipes and the collecting pipe in an exhaust manifold of an internal combustion engine.SOLUTION: In a manufacturing method of a collecting pipe 11 into which downstream-side end parts 20 of a plurality of branch pipes in an exhaust manifold are inserted in a bundle, in the collecting pipe 11, a portion located at a mating part 22 between downstream-side end parts 20, 20 of the adjacent branch pipes at an external peripheral face of an opening end part 12 at a side to which the branch pipes are inserted is pressed to an inside direction from the outside to form a recess 14, and at least a part of the external peripheral face of the opening end part 12 other than the recess 14 is pressed to the inside direction from the outside, thus forming the opening end part 12.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a method for manufacturing a collecting pipe.

  Conventionally, as shown in FIG. 12, an exhaust manifold 101 of an internal combustion engine has a plurality of branch pipes 102 through which exhaust gas discharged from each cylinder of a multi-cylinder internal combustion engine flows, There are some which gather at the unit 103 and guide the exhaust gas to a subsequent purifier or a silencer. A collecting pipe 104 is fitted on the collecting portion 103 of the branch pipe 102.

  In the gathering portion 103, as shown in FIG. 13 which is a sectional view taken along the line BB in FIG. 12, the downstream end portion of the branch pipe 102 is formed in a fan shape with an inner angle of 90 °. The downstream end is bundled so that the cross section is substantially circular, and a partition plate 105 is provided between the downstream ends of the adjacent branch pipes 102. Then, after the downstream end portions of the partition plate 105 and the branch pipe 102 are fixed to each other by welding, these are inserted into the collecting pipe 104, and the opening end portion of the collecting pipe 104 is extended over the entire circumference. What is fixed to 102 etc. by welding is known (for example, refer patent document 1).

  In the prior art described in Patent Document 1, as shown in FIG. 13, between the inner peripheral surface of the collecting pipe 104 in the collecting portion 103 and the outer portion in the mating portion 107 of the adjacent branch pipes 102 and 102. A triangular gap 108 is generated.

  If the gap 108 is larger than the diameter of the welding wire, spattering is likely to occur during welding, and there is a concern that the welding quality will deteriorate. Moreover, the generated spatter may enter the exhaust manifold from the gap 108.

  Therefore, as a method of reducing the gap 108, it has been proposed to reduce the gap 108 by previously narrowing the opening end of the collecting pipe 104 at a plurality of locations in the circumferential direction to form recesses (patent). Reference 2).

JP 2009-36166 A JP-A 63-290618

  However, the concave portion of the collecting pipe 104 described in Patent Document 2 is formed by locally pressing the outer peripheral surface of the collecting pipe 104 from the outside by the forming protrusions, and the collecting pipe 104 other than the concave portion is formed. The outer peripheral surface of the general part is not pressed or constrained from the outside, and the shape accuracy of the opening end part may be deteriorated. When this shape accuracy deteriorates, it may be difficult to insert the downstream end portion of the branch pipe 102 into the collecting pipe 104. Further, the gap between the outer peripheral surface of the branch pipe 102 and the inner peripheral surface of the general part of the collecting pipe 104 may vary in the circumferential direction, and the welding quality may be deteriorated.

  Accordingly, an object of the present invention is to propose a method of manufacturing a collecting pipe that solves the above problems.

In order to solve the above-described problem, the present invention provides a collecting pipe manufacturing method in which downstream ends of a plurality of branch pipes in an exhaust manifold are bundled and inserted.
In the collecting pipe, a concave portion is formed by pressing a portion located at a joint portion between the downstream end portions of adjacent branch pipes on the outer peripheral surface of the opening end portion on the side where the branch pipe is inserted from the outside toward the inside. With forming
The opening end is shaped by pressing at least a part of the outer peripheral surface of the opening end other than the recess inward from the outside.

  Moreover, you may press the outer peripheral surface of an opening edge part from an outer side to an inner side in the state which inserted the metal core in the said opening edge part.

  Further, the outer peripheral surface of the opening end may be pressed inward from the outside in a state where the downstream end of the branch pipe is bundled and inserted into the opening end.

  Moreover, after providing a notch in the said opening edge part, this notch part may be pressed and bent inside from the outer side, and the said recessed part may be formed.

  According to the present invention, in the collecting pipe, a portion located at a joint portion between the downstream end portions of adjacent branch pipes on the outer peripheral surface of the opening end portion on the side where the branch pipe is inserted is pressed from the outside to the inside direction. And forming at least a part of the outer peripheral surface of the opening end other than the recess from the outside toward the inside by shaping the opening end, compared with the prior art. The gap between the opening end of the collecting pipe and the mating section can be narrowed, and the variation in the circumferential direction of the gap between the opening end of the collecting pipe and the branch pipe can be reduced, so that the welding quality can be improved.

The longitudinal cross-sectional view of the processing apparatus which concerns on Example 1 of this invention. Sectional drawing of the state which moved the split type | mold to the centripetal direction from the state of FIG. Sectional drawing of the state which moved the division type | mold to the radial direction from the state of FIG. FIG. 3 is an end view taken along line AA in FIG. 2. The end view of the state which inserted the branch pipe and the partition plate in the collecting pipe which concerns on Example 1 of this invention. The side end view of the processing apparatus which concerns on Example 3 of this invention. The side view of the collecting pipe for demonstrating the manufacturing method of the collecting pipe which concerns on Example 5 of this invention. The left view of FIG. The longitudinal cross-sectional view for demonstrating the method to form the cut which concerns on Example 5 of this invention. FIG. 10 is a cross-sectional view of FIG. 9. Sectional drawing of the state which inserted the branch pipe and the partition plate in the collecting pipe which concerns on Example 5 of this invention. The front view of the exhaust manifold of a prior art. BB sectional drawing of FIG.

  A mode for carrying out the present invention will be described based on an embodiment shown in the drawings. In addition, in order to avoid complication of the drawing, hatching was omitted for members formed using a thin plate material such as a collecting pipe, a branch pipe, and a partition plate.

[Example 1]
FIGS. 1-4 shows the processing apparatus 1 used for the manufacturing method of the collecting pipe which concerns on Example 1 of this invention.

  As shown in FIG. 1, the processing device 1 is provided on a fixed base 2 and an upper portion of the fixed base 2 so as to be movable in a radial direction around a predetermined axis that stands upward from the fixed base 2. It has split molds 3A and 3B.

  As shown in FIG. 4, the fixed base 2 is provided with four first split molds 3A and four second split molds 3B. The first split mold 3A and the second split mold 3B are arranged in the circumferential direction. Alternatingly arranged, the two split molds 3A and 3B are divided into a total of eight in the circumferential direction. Further, as shown in FIG. 4, in a state where the respective divided molds 3 </ b> A and 3 </ b> B are located on the innermost side, the adjacent divided molds 3 </ b> A and 3 </ b> B are in contact with each other, and as illustrated in FIG. The outer surface 3d of each of the split molds 3A and 3B is formed in a tapered shape so that the outer shape formed by the split molds 3A and 3B is substantially circular and has a truncated conical shape with a diameter decreasing toward the upper side. ing.

  Inside the split mold 3A, as shown in FIG. 4, a molding surface 3a having a circular cross section is formed. Formed on the inner side of the split mold 3B is a molding surface 3c that has a convex portion 3b in the central portion in the circumferential direction and is formed so that the cross section of the other portion is arcuate.

  On the outside of the split molds 3A and 3B, an annular clamping mold 6 movable in the vertical direction is provided in a fitted state. As shown in FIGS. 1 to 3, the inner side surface 6 a of the clamping die 6 is formed in a truncated cone shape corresponding to the outer side surface 3 d of the split dies 3 </ b> A and 3 </ b> B and reducing in diameter toward the upper side.

  A ram 8 is fixed to the clamping mold 6, and the clamping mold 6 is moved up and down together with the ram 8 by moving the ram 8 up and down by a hydraulic cylinder 9. The split dies 3A and 3B are always urged radially in the radial direction by an urging portion such as a spring (not shown). With the above structure, when the clamping mold 6 is raised, the outer surface 3d of the split molds 3A and 3B and the inner surface 6a of the clamp mold 6 slide, and the split molds 3A and 3B move in the radial direction in the radial direction. When the clamping mold 6 is lowered, the outer surface 3d of the split molds 3A and 3B and the inner side surface 6a of the clamp mold 6 slide, and the split molds 3A and 3B move in the centripetal direction in the radial direction. ing.

  Further, the cored bar 10 is fixed to the base 2 at the center of the split molds 3A and 3B, and the outer peripheral surface of the cored bar 10 is the split molds 3A and 3B as shown in FIG. It is formed in a shape corresponding to the molding surfaces 3a and 3c, and recessed portions 10a are formed at a predetermined interval in the circumferential direction.

  Next, the manufacturing method of the collecting pipe using the said processing apparatus 1 is demonstrated.

  First, as shown in FIG. 1, when the ram 8 is raised by the hydraulic cylinder 9, the clamping die 6 is raised, and the divided die 3 </ b> A, 3 </ b> B is moved in the radial direction by the urging portion, and then the collecting pipe to be molded 11 open end portions 12 are attached at predetermined positions between the split dies 3A and 3B and the cored bar 10. The open end portion 12 is formed in a perfect circle in cross section, and other portions can have any shape.

  Next, as shown in FIG. 2, when the hydraulic cylinder 9 is operated and the ram 8 is lowered, the clamping die 6 is lowered and the split dies 3A and 3B are pushed and moved in the centripetal direction. As a result, the open end 12 on the side where the branch pipe is inserted in the collecting pipe 11 is pressed inward from the outside by the split dies 3A and 3B over the entire circumferential direction, and the split dies 3A and 3B. And four concave portions 14 are formed in the opening end portion 12 at appropriate intervals in the circumferential direction by the convex portions 3b of the split mold 3B and the concave portions 10a of the core metal 10. In addition, the entire open end 12 is shaped, and the open end 12A is shaped like a petal as shown in FIG.

  Next, as shown in FIG. 3, the ram 8 is raised by the hydraulic cylinder 9, the split dies 3A, 3B are retracted in the radial direction by the urging portion, the molded collecting tube 11A is removed, and the assembly of a predetermined shape is performed. Tube 11A is obtained.

  Separately, as shown in FIG. 5, four downstream end portions 20 of the branch pipe formed in a fan shape with an inner angle of 90 ° are bundled so that the cross section is substantially circular, and adjacent downstream end portions A partition plate 21 is provided between the portions 20 and 20, and the partition plate 21 and the downstream end portion 20 of the branch pipe are fixed to each other by welding.

  The opening end 12A of the collecting pipe 11A is externally fitted to the partition plate 21 and the downstream end 20 of the branch pipe fixed to each other by welding. At this time, as shown in FIG. 5, the gap between the concave portion 14 and the mating portion 22 is inserted inside the concave portion 14 so that the mating portion 22 of the adjacent downstream end portions 20 and 20 is located. Can be made narrower than the prior art described in Patent Document 1.

  Next, the downstream end 20 of the branch pipe, the partition plate 21, and the open end 12A of the collecting pipe 11A are fixed to each other by welding over the entire circumference in the circumferential direction to obtain an exhaust manifold. The gap between the open end 12A of the molded collecting pipe 11A and the downstream end 20 during the welding is compared with the prior art described in Patent Document 2 over the entire circumference. Uniform and close to each other, and the welding quality can be dramatically improved.

  The moving method for moving the split molds 3A and 3B in the radial direction is not limited to the above moving method and can be arbitrarily set.

  Moreover, in the said Example 1, although the number of division | segmentation type | molds 3A and 3B was set to eight in total, the number can be set arbitrarily. Further, one split mold 3A and one split mold 3B adjacent in the circumferential direction may be integrally formed.

[Example 2]
In the first embodiment, the open end 12 of the collecting pipe 11 is pressed from the outside to the inside by the divided dies 3A and 3B over the entire circumferential direction, and the divided dies 3A and 3B and the cored bar 10 are used. Although formed by pressing, the concave portion 14 is formed by the convex portion 3b of the split mold 3B and the concave portion 10a of the cored bar 10, and at least the outer peripheral surface of the opening end portion 12 that easily deforms as the concave portion 14 is molded. The portion may be partially pressed from the outside to the inside by the split dies 3A and 3B, and may be shaped by being pinched by the split dies 3A and 3 and the cored bar 10.

  Since the other structure is the same as that of the first embodiment, description thereof is omitted.

  Also in the second embodiment, the same effects as in the first embodiment are obtained.

[Example 3]
In the first and second embodiments, the cored bar 10 is provided at the center of the split molds 3A and 3B. However, as shown in FIG. 12 may be pressed from the outside to the inside to form the recess 14 and the whole may be shaped.

  Since other structures are the same as those in the first and second embodiments, description thereof is omitted.

  The third embodiment has the same effect as the first and second embodiments although the processing accuracy is slightly lower than the first and second embodiments because the core bar 10 is not provided.

[Example 4]
In the first to third embodiments, after the recess 14 is formed in the opening end 12 of the collecting pipe 11, the downstream end 20 and the partition plate 21 of the branch pipe are inserted, but the state before the recess 14 is formed After inserting the partition plate 21 and the downstream end 20 of the branch pipe fixed to each other by welding into the open end 12 of the collecting pipe 11, the split molds 3A and 3B are used in the same manner as in the third embodiment. By pressing from the outside of the opening end 12, the recess 14 may be formed, and the entire opening in the circumferential direction or part of the opening end 12 may be shaped.

  Since other structures are the same as those in the first to third embodiments, description thereof is omitted.

  In the fourth embodiment, the same effects as in the first to third embodiments are obtained.

  In the fourth embodiment, the downstream end 20 and the partition plate 21 of the branch pipe are inserted, and then the concave portion 14 is formed and the whole is molded, so that the downstream end 20 of the branch pipe is formed. Both of the partition plate 21 and the opening end portion 12A of the collecting pipe 11A are plastically deformed and closely adhered to each other, so that the welding quality can be further improved.

[Example 5]
The fifth embodiment is a modification of the first to fourth embodiments.

  First, as shown in FIGS. 9 and 10, a core metal 31 for cutting is inserted into the open end 12 of the collecting pipe 11. The cutting core bar 31 is provided with four grooves 33 extending in the axial direction thereof at appropriate intervals in the circumferential direction.

  Next, as shown in FIG. 10, by inserting the cutting tool 35 into the groove 33 from the outside of the open end 12 of the collecting pipe 11, as shown in FIGS. 7 and 8, The cuts 30 in the axial direction are formed at appropriate intervals in the four circumferential directions.

  Next, the open end 12 of the collecting pipe 11 is pressed from the outside by the split dies 3A and 3B or is clamped by the split dies 3A and 3B and the cored bar 10 by the same method as in the first to fourth embodiments. Then, the notch 30 is bent inward to form a recess 14A as shown in FIG.

  Since the other structure is the same as that of the said Examples 1-4, the description is abbreviate | omitted.

  In Example 5, the same effects as in Examples 1 to 4 are obtained.

[Example 6]
In the first to fifth embodiments, the present invention is applied to a method for manufacturing a collecting pipe used for an exhaust manifold for a four-cylinder internal combustion engine having four branch pipes. The number of branch pipes, partition plates 21 and recesses 14 can be arbitrarily set.

  Since the other structure is the same as that of the said Examples 1-5, the description is abbreviate | omitted.

  In Example 6, the same effects as in Examples 1 to 5 are obtained.

[Other Examples]
The shape of the downstream end portion of the branch pipe is not limited to the fan shape described in the above embodiment, and can be arbitrarily set, such as a polygonal shape or an irregular shape. The shapes of the molding surfaces 3a and 3c of the split dies 3A and 3B are It can be arbitrarily formed according to the shape of the downstream end or the like.

DESCRIPTION OF SYMBOLS 10 Core metal 11, 11A Collecting pipe 12, 12A Open end part 14, 14A Recessed part 20 Downstream side end part of branch pipe 22 Matching part 30 Cutting

Claims (4)

In the manufacturing method of the collecting pipe in which the downstream end portions of the plurality of branch pipes in the exhaust manifold are bundled and inserted,
In the collecting pipe, a concave portion is formed by pressing a portion located at a joint portion between the downstream end portions of adjacent branch pipes on the outer peripheral surface of the opening end portion on the side where the branch pipe is inserted from the outside toward the inside. With forming
A method for manufacturing a collecting pipe, wherein at least a part of the outer peripheral surface of the opening end other than the recess is pressed inward from the outside to shape the opening end.   The method for manufacturing a collecting pipe according to claim 1, wherein the outer peripheral surface of the opening end is pressed inward from the outside in a state where the cored bar is inserted into the opening end.   2. The manufacturing of a collecting pipe according to claim 1, wherein the outer peripheral surface of the opening end is pressed inward from the outside in a state where the downstream end of the branch pipe is bundled and inserted into the opening end. Method.   The cut portion is formed by pressing and bending the cut portion inward from the outside after forming the cut at the opening end portion, to form the concave portion. Manufacturing method of collecting pipe.

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