JP4570541B2 - Manufacturing method and manufacturing apparatus for inner and outer double cylinders - Google Patents

Description

  The present invention relates to a manufacturing method and a manufacturing apparatus for an inner / outer double cylinder used as, for example, a finisher pipe, an exhaust pipe or various heat insulating pipes in an exhaust system of an automobile engine.

  Conventionally, in an exhaust system of an automobile engine, for example, a muffler is generally arranged at the rear lower part of a vehicle body, and a finisher pipe is attached to a tail pipe for releasing exhaust gas from the muffler into the atmosphere behind the vehicle body. It is known to improve the appearance and outer tube appearance from the rear of the vehicle body.

  Various types of finisher pipes have been proposed in the past. Recently, for example, a metal cylinder having a circular cross section or an oval cross section is used, and at least the rear end thereof is folded back into a vertical U section. Many are formed in an inner and outer double.

  In this case, conventionally, the inner cylinder body and the outer cylinder body are separately molded and folded at one end in a U shape, and the end of the other cylinder is welded to the folded end. Although fixed, the number of parts and the number of assembling steps are large, making the production cumbersome and increasing the cost. In addition, the welded part is often exposed to the outside and the outer tube shape is damaged.

  Therefore, in the following Patent Document 1, after forming a plate material as a raw material into a bottomed cylindrical shape by drawing one side in the thickness direction, the bottom portion is drawn in the opposite direction to the above-mentioned double-sided inner and outer doubles. Although it has been proposed to manufacture a finisher pipe made of a cylindrical body, there is a limit to the drawing depth in the drawing process as described above, and it is difficult to produce a double cylinder body that is long in the axial direction. . In addition, there is often a risk that the thickness and the thickness may be varied or distorted during processing, resulting in a decrease in rigidity and durability.

JP 2003-166424 A

  The present invention has been proposed in view of the above-described problems, and an object of the present invention is to provide a manufacturing method and a manufacturing apparatus capable of manufacturing the above-described inner and outer double cylinders easily and inexpensively.

  In order to achieve the above object, a method and an apparatus for manufacturing an inner and outer double cylinder according to the present invention have the following configurations. That is, the manufacturing method of the inner and outer double cylinders according to the present invention provides a cylindrical cored bar for manufacturing an inner / outer double cylinder having a circular or oval cross section having a folded portion having a U-shaped longitudinal section on at least one end side. The material cylinder is disposed on the inner peripheral surface side of the material cylinder, and at least a part of the material cylinder is moved by sequentially moving one end side of the material cylinder from the one end side of the cylindrical cored bar to the outer peripheral surface side. The inside and outside double cylinders are manufactured by reversing the front and back sides.

  An inner / outer double cylinder manufacturing apparatus according to the present invention is an apparatus for manufacturing an inner / outer double cylinder having a circular or oval cross-sectional shape having a folded portion having a U-shaped longitudinal section on at least one end side, A cylindrical cored bar for reversing the material cylinder and a pair of blank holders for gripping one end of the material cylinder, the cylindrical cored bar being arranged and fixed on a fixed base, and the cylinder The material cylinder is arranged on the inner peripheral surface side of the core metal bar, and an outward flange portion formed on one end side of the material cylinder body is projected radially outward from one end side of the cylindrical core metal. Then, the flange portion thus projected is gripped by the pair of blank holders, and is sequentially moved from one end side of the cylindrical cored bar along the outer peripheral surface side so that at least a part of the material cylinder is turned upside down. It is characterized by manufacturing inner and outer double cylinders That.

  As described above, the manufacturing method of the inner and outer double cylinders according to the present invention is configured such that the one end side of the material cylinder arranged on the inner peripheral surface side of the cylindrical core metal is extended from the one end side of the cylindrical core metal to the outer peripheral surface. Since the inner and outer double cylinders are manufactured by reversing at least part of the material cylinder by sequentially moving the inner and outer double cylinders, the inner and outer double cylinders having a circular or oval cross section are easily and inexpensively manufactured. It becomes possible.

  Moreover, since the manufacturing apparatus of the inner and outer double cylinders according to the present invention has the above-described configuration, the cylindrical cored bar for reversing the material cylinder and the fixed base for arranging and fixing the cylindrical cored bar are provided. And forming a flange portion facing outward on one end side of the material cylinder, and providing a pair of blank holders for holding the flange portion, and holding the flange portion of the material cylinder with the blank holder The above-described inner and outer double cylinders can be easily manufactured with a simple configuration in which the cylindrical cored bar is sequentially moved from one end side to the outer peripheral surface side.

  Hereinafter, a method and an apparatus for manufacturing an inner / outer double cylinder according to the present invention will be described in detail by taking as an example the case of manufacturing a finisher pipe used in an exhaust system of an automobile engine.

  FIG. 1 (a) is a longitudinal side view showing an example of a finisher pipe as an inner / outer double cylinder to which an inner / outer double cylinder manufacturing method and manufacturing apparatus according to the present invention is applied, and FIG. is there.

  The illustrated finisher pipe 1 includes an inner cylindrical portion 1a and an outer cylindrical portion 1b, which are integrally formed of the same metal, in this embodiment, a stainless steel plate. In the present embodiment, the inner cylindrical portion 1a is formed shorter than the outer cylindrical portion 1b. However, the inner cylindrical portion 1a can be formed substantially the same length or longer than the outer cylindrical portion 1b.

  Further, the finisher pipe 1 has a rear end folded portion (right end portion in FIG. 1A) 1c inclined at a predetermined angle θ (about 20 degrees in the figure) with respect to a plane α perpendicular to the axial direction of the pipe 1. However, it may be formed in parallel with the plane α in the perpendicular direction. In the figure, reference numeral 2 denotes a tail pipe, and the inner cylinder portion 1a of the finisher pipe 1 is fitted to the rear end portion thereof, and the finisher pipe 1 is prevented from being detached from the tail pipe 2 by a mounting band or the like omitted in the drawing. It is.

  In manufacturing the inner and outer double cylinders such as the finisher pipe 1 as described above, for example, it may be manufactured in the following manner, and an example thereof will be described in order according to the process explanatory diagrams of FIGS. First, a blank plate made of a stainless steel material (not shown in the figure) (SUS304 is used in this embodiment) is punched into a predetermined shape (blank process), as shown in FIG. 10 is formed.

  Next, the material plate 10 is rolled into a cylindrical shape as shown in FIG. 2B, both end portions 10 a and 10 a are butted together, and joined by seam welding or the like to form the material cylinder 11. At that time, as shown in the illustrated example, the extension protrusions 10b are formed on both sides of the end portions 10a and 10a, respectively, and the protrusions 10b are welded together with the extension protrusions 10b, as shown in FIG. When excised, the butt welds can be satisfactorily joined over the entire length without causing poor welding or the like at the ends.

  The material cylinder 11 formed into a cylindrical shape as described above is continuously processed into an oval (elliptical) cross section as shown in FIG. 2C, and one end of the cylinder 11 after the foam processing. 11A, in this embodiment, as shown in FIG. 3A, which is a cross-sectional view taken along line AA of FIG. 2C, the folded portion 1c with respect to the surface α perpendicular to the axial direction of the cylindrical body 11 It is formed in a state where it is inclined by substantially the same angle θ. In addition, the end 11B opposite to the above is slightly inclined so that it is substantially flat in the direction perpendicular to the axial direction of the cylinder 11 when a front / back reversing process (hereinafter also simply referred to as reversing process) described later is performed. Is formed.

  Next, the material cylinder 11 is reversed to form at least a part of the cylinder 11 inside and outside, and prior to that, as shown in FIGS. 3 (b) and 3 (c), the cylinder 11 If the flange portion 11F is formed in advance at one end, the above reversing process can be easily performed. In the present embodiment, the flange portion 11F is formed by bending the inclined end portion 11A outward at a predetermined angle δ, in the case of FIG. At this time, first, as shown in FIG. 3 (b), it is bent at an angle of about 45 degrees with respect to the extension line L of the cylindrical body surface, and further, substantially perpendicular to the cylindrical body surface as shown in FIG. 3 (c). When bent, the flange portion 11F can be easily formed.

  When the flange portion 11F is formed at one end of the material cylinder 11 as described above, the cylinder body 11 is subjected to a front / back reversing process for reversing the front / back using a cylindrical cored bar or the like, at least a part of which is An internal / external double cylinder formed into an internal / external double is formed. FIG. 4 shows an example of the process. First, as shown in FIG. 4A, the material cylinder 11 is arranged on the inner peripheral surface side of the cylindrical cored bar 20, and one end side of the material cylinder 11 is arranged. For example, the flange portion 11F is gripped by a holder or the like not shown in the figure, and the cylindrical cored bar from one end side (the upper end side in the figure) of the cylindrical cored bar 20 as shown in FIGS. The inner and outer double cylinders may be formed by reversing the front and back while sequentially folding back into a U-shape along the outer peripheral surface of 20.

  FIG. 5 is a schematic configuration diagram showing an example of an apparatus for manufacturing the inner and outer double cylinders according to the above-described process. The apparatus of the illustrated example is mounted on a plurality of support legs 21 as shown in FIG. A cored bar support 23 is integrally provided on the fixed base 22 that is disposed and fixed, and the cylindrical cored bar 20 is disposed and fixed on the cored bar support 23. A movable base 25 for feeding a work is provided on the core metal support base 23 in the cylindrical core metal 20 so as to be movable up and down via a movable rod 24, and the material cylinder as a work is provided on the movable base 25. 11 is placed with the flange portion 11F facing up.

  A pair of upper and lower ring-shaped blank holders 26 and 27 for holding the flange portion 11F of the material cylinder 11 are provided above the fixed base 21 so as to be movable up and down via movable rods 28 and 29, respectively. The opposing surfaces of the blank holders 26 and 27 are formed in a state in which the central portion in the left-right direction is inclined as shown in FIG. 5A in accordance with the inclined portion of the flange portion 11F.

  Further, a centering core 30 is provided in the ring-shaped blank holders 26 and 27 so as to be movable up and down via a movable rod 31, and a lower narrow diameter portion 30 a of the centering core 30 is formed on the material cylinder 11. By fitting to the upper inner surface, the material cylinder 11 and the cylindrical cored bar 24 are positioned and held at a predetermined center position.

  In the above configuration, when the material cylinder 11 is reversed, first, the lower blank holder 27 of the pair of blank holders 26 and 27 is formed into a cylindrical upper surface as shown in FIG. It arrange | positions so that it may become the substantially same height position as the upper end position of the metal core 20, and the raw material cylinder 11 in the cylindrical metal core 20 in the state which the upper blank holder 26 and the centering metal core 30 were evacuated upwards. Is inserted and fitted with the flange portion 11F facing up.

  In this state, when the centering core 30 is moved downward and inserted and fitted into the upper portion of the material cylinder 11 as shown in FIG. 5B, the material cylinder is interposed between the centering core 30 and the cylindrical core 20. At the same time as the upper part of the body 11 is pinched, the cylindrical cored bar 20 and the upper part of the material cylinder 11 are positioned and fixed at predetermined positions. Further, the flange portion 11F of the cylindrical body 11 is located on the lower blank holder 27 in a state of projecting radially outward from the cylindrical cored bar 20 above the cylindrical cored bar 20, and in this state. When the upper blank holder 26 is moved downward, the flange portion 11 </ b> F is held between the blank holders 26 and 27.

  Next, as shown in FIG. 6A, when the blank holders 26 and 27 holding the flange part 11F are moved downward while raising the movable base 25 on which the material cylinder 11 is placed, the material cylinder 11 is moved. The upper and lower sides of the cylindrical core bar 23 are sequentially folded back in a U-shape while the front and back are reversed, and then move downward along the outer peripheral surface of the cylindrical core bar 2. As a result, the material cylinder 11 is composed of an inner and outer double portion including an inner cylinder portion 11 a located on the inner peripheral surface side of the cylindrical core metal 2 and an outer cylinder portion 11 b located on the outer peripheral surface side of the cylindrical core metal 2. Will be formed.

  And when those inner and outer cylinder parts 11a and 11b are formed to a predetermined length as shown in FIG. 6 (b), stop the raising operation of the movable base 25 and the lowering operation of the blank holders 26 and 27. An inner / outer double cylinder having a desired length as shown in FIG. 6B is formed, and if it is taken out from the apparatus, an inner / outer double cylinder 11 ′ as shown in FIG. 7 is manufactured. Then, the inner and outer double cylinders 11 ′ are cut at a chain line position C in the drawing, the end on the flange portion 11F ′ side is cut off, and if desired processing is performed as required, the finisher as shown in FIG. The pipe 1 is obtained.

  As described above, in manufacturing the inner and outer double cylinders such as the finisher pipe in the present invention, the material cylinder 11 is disposed on the inner peripheral surface side of the cylindrical cored bar 20, and the material cylinder 11 is formed into the cylinder shape. Since the inner and outer double cylinders are manufactured by sequentially reversing the front and back along the outer peripheral surface side from one end side of the cored bar 20, the inner and outer double cylinders as described above can be manufactured easily and inexpensively.

  In particular, the inner and outer double cylinders having a circular cross section can be easily manufactured even in the inner and outer double cylinders having an oblong cross section (including an oval shape) as shown in the illustrated example. Even if the one-end folded portion of the cylindrical body is an inner and outer double cylindrical body inclined at a predetermined angle θ with respect to a plane α perpendicular to the axial direction of the cylindrical body, it can be easily manufactured.

  In addition, although the said embodiment demonstrated as an example the finisher pipe used for the exhaust system of a motor vehicle engine, it is not restricted to this, For example, it is applicable also to the inner and outer double cylinders used for a muffler, an exhaust pipe, etc. Is an internal / external double cylinder for the intake system, which is limited to the exhaust system of the engine, and other various types intended for heat insulation, heat retention or durability, such as a thermos, a solar heat collecting tube, or a fuel cell reformer. It can also be applied to inner and outer double cylinders.

  As described above, the manufacturing method and the manufacturing apparatus for the inner and outer double cylinders according to the present invention have the above-described configuration, so that the inner and outer double cylinders can be easily and inexpensively manufactured. The degree of freedom in selecting a manufacturing method when manufacturing a cylindrical body can be increased.

(A) is the vertical side view which shows an example of the finisher pipe as an internal / external double cylinder to which this invention is applied, (b) is the back view. (A)-(c) is explanatory drawing which shows an example of the front process at the time of manufacturing an inner / outer double cylinder. (A)-(c) is explanatory drawing which shows an example of the formation process of a flange part. (A)-(c) is explanatory drawing which shows an example of a front-back inversion process. (A) is a partially longitudinal front view showing an example of an inner / outer double cylinder manufacturing apparatus, and (b) is the same as above in a state where the flange portion of the material cylinder is held by a blank holder. (A) is a partially longitudinal front view of the manufacturing apparatus in a state in which the blank holder is moved down, and (b) is the same as above in a state where processing is completed. The longitudinal cross-sectional view of the internal / external double cylinder manufactured with the said manufacturing apparatus.

Explanation of symbols

1 Inner and outer double cylinder (finisher pipe)
DESCRIPTION OF SYMBOLS 1a Inner cylinder part 1b Outer cylinder part 10 Material board 11 Material cylinder 11A, 11B End part 11F Flange part 11a Inner cylinder part 12b Outer cylinder part 2 Tail pipe 20 Cylindrical core metal 21 Support leg 22 Fixed base 23 Fixed base 24 Movable Guide rod 25 Movable base 26, 27 Blank holder 28, 29 Movable rod 30 Centering core 31 Movable rod

Claims (4)

  In manufacturing an inner / outer double cylinder having a circular cross section or an oval cross section having a U-shaped folded section at least at one end side, a material cylinder is arranged on the inner peripheral surface side of the cylindrical cored bar, and the material The inner and outer double cylinders are manufactured by reversing at least a part of the raw material cylinder by sequentially moving one end side of the cylinder body from one end side of the cylindrical core metal along the outer peripheral surface side. A method for producing an inner and outer double cylinder.   An apparatus for manufacturing an inner / outer double cylinder having a circular or oval cross section having a folded portion having a U-shaped longitudinal section on at least one end side, and a cylindrical cored bar for reversing the material cylinder A pair of blank holders for gripping one end of the material cylinder, the cylindrical cored bar is disposed and fixed on a fixed base, and the material cylinder is disposed on the inner peripheral surface side of the cylindrical cored bar. And projecting the outward flange portion formed on one end side of the raw material cylindrical body radially outward from the one end side of the cylindrical core metal, and the projecting flange portion with the pair of blank holders The inner and outer double cylinders are manufactured by reversing at least a part of the material cylinder by sequentially moving from one end side of the cylindrical cored bar along the outer peripheral surface side in the gripped state. Equipment for manufacturing inner and outer double cylinders.   The centering mandrel according to claim 2, further comprising a centering mandrel that is inserted and fitted inside the cylindrical metal core and the inner end of the material cylinder to hold the cylindrical metal core and the material cylinder substantially concentrically. Equipment for manufacturing inner and outer double cylinders.   When the protruding flange portion is held by a pair of blank holders and moved along the outer peripheral surface from one end side of the cylindrical cored bar, the material cylinder is moved to one end side of the cylindrical cored bar. The apparatus for manufacturing an inner / outer double cylinder according to claim 2 or 3, comprising a movable base for moving and energizing.

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