JP4263991B2 - Method for manufacturing irregularly bent tapered tube and irregularly bent tapered tube manufactured by this method - Google Patents

Description

  The present invention relates to a taper tube applicable to an exhaust pipe for flowing exhaust gas discharged from an engine to the muffler side, for example, in an automobile, a motorcycle, and the like. This relates to a tapered tube.

For example, in an automobile or motorcycle, a tapered pipe whose axis is bent three-dimensionally (hereinafter referred to as an irregularly bent tapered pipe) is applied as an exhaust pipe that guides exhaust gas discharged from the engine to the muffler side. There is.
In order to manufacture such an irregularly curved tapered tube 1 ', for example, as shown in FIG. 6, a short tubular member P in a divided state is joined in the longitudinal direction by welding or the like, and a desired tapered tube is formed. There is a technique to get. However, such a manufacturing method is generally costly due to increased welding and the like, and it cannot be said that it is a reasonable method particularly in the mass production stage.

For this reason, the present applicant has manufactured a desired tubular member (collecting pipe) by using a blank material as a starting material and pressing it as a manufacturing method for reducing the joining process such as welding as much as possible. The technique to do is developed and it has reached the patent application (refer patent document 1). In Patent Document 1, since the welding process can be reduced or eliminated as much as possible, a corresponding effect is achieved in terms of cost reduction and the like.
However, in the automobile-related parts industry described above, the demand for cost reduction and weight reduction for each of the component parts is extremely severe, and even with exhaust pipes (tapered pipes), exhaust gas is efficiently used. In addition to improving the original function of flowing in a stream, rational manufacturing methods that can always achieve further cost reductions are intensively studied.
JP 2002-188440

  The present invention has been made as a part of such research and development, and it is possible to reduce the number of processes and reduce the number of joints such as welding, thereby further reducing the cost. This is an attempt to develop a manufacturing method of a novel deformed curved taper tube that can be realized.

That is, the method of manufacturing the irregularly bent tapered tube according to claim 1 has a small-diameter side open end (11) and a large-diameter side open end (12) , and the shaft core (10) is bent or curved three-dimensionally. In producing a deformed curved taper pipe (1)
This deformed curved taper pipe (1) is a blank material (B) that forms a non-axisymmetric deformed fan shape as a starting material, and this blank material (B) is punched (21, 31 ) And dies (22, 32) as a main component and bent by an opposing mold (2, 3) to form a desired tapered tube shape,
When bending the blank material (B) into a U-shaped cross section , the strong bend portion (15) in the completed shape of the tapered tube is formed without using the center portion of the blank material (B) as the center of U-bending. The strong bend (15) is sandwiched from both sides by the die (22) and punch (21), and the shape of the strong bend (15) is the blank material (B ) at the initial stage of the bending process. ) Is reproduced as a feature.

In addition to the requirement of claim 1, the manufacturing method of the irregularly bent taper pipe according to claim 2 is the same in the bending process of aligning both edges (S) of the blank material (B) after the U bending process. The edge joining portion (14) serving as a portion is set to a relatively flat and substantially flat portion (16) in the completed shape of the tapered tube.

Furthermore, in addition to the requirement of claim 2, the manufacturing method of the irregularly bent taper pipe according to claim 3 is a core at the opening end in the bending step of aligning both end edges (S) of the blank material (B). It is characterized in that gold is inserted and pressed.

The irregularly curved tapered tube according to claim 4 comprises a small-diameter side open end (11) and a large-diameter side open end (12) , and the shaft core (10) is three-dimensionally bent or curved. In this taper tube, the blank material (B) having a non-axisymmetric deformation fan shape is bent by the manufacturing method according to claim 1, 2, or 3 to obtain a desired tapered tube shape. It is characterized by being formed .

  The above-described problems can be solved by using the configuration of the invention described in each of the claims. That is, according to the first aspect of the present invention, since a general blank material can be used as a starting material, it is possible to significantly reduce the material cost, the processing cost, and the like. At the initial stage of the bending process, a strong bend with a relatively large bend is sandwiched from both sides with a punch and a die, so that the shape of the strong bend can be reliably realized, and the shape reproducibility (improvement of the finished product) (Shape).

  According to the second aspect of the present invention, the both ends of the blank material can be relatively easily abutted, and thereafter, brazing, welding, and the like applied to the abutting portion can be performed cleanly.

Furthermore, according to the invention of the third aspect, in the bending step of abutting the both end edges of the blank material, the blank material is wound around the core bar, and the shape of the opening end portion of the tapered tube is reproduced. Open ends with the desired diameter and shape can be reproduced almost faithfully. The opening end of the taper tube is often connected to other members such as a muffler in particular, and can be formed according to the desired shape and dimensions by press molding using a cored bar. , the only assembling of consolidation made reliable and easy.

  Furthermore, according to the invention described in claim 4, since the irregularly curved taper tube whose axis is bent in various directions can be actually bent from a single blank, this kind of irregularly curved taper tube is used. Thorough cost reduction can be achieved.

The best mode for carrying out the present invention is such that such an irregularly bent taper tube can be actually formed by bending from a single blank, thereby reducing the number of processes and making an inexpensive variant. A bent taper tube can be provided.
Hereinafter, the present invention will be described based on the following examples. In the description, first, the deformed curved taper tube 1 to be manufactured according to the present invention will be described, and then the manufacturing method of the deformed curved taper tube 1 will be described.

As shown in FIGS. 1 and 2, the irregularly curved tapered tube 1 to be manufactured in the present invention means a tapered tube in which an axis (axial center) passing through the center of the tube is three-dimensionally bent or curved. . Here, it is assumed that the axis of the irregularly bent tapered tube 1 is 10, the small diameter side open end is 11, and the large diameter side open end is 12.
In the embodiment shown in FIGS. 1 and 2, the axially bent core 1 is bent in the middle portion of the pipe, and the directions (opening directions) of the small-diameter side open end 11 and the large-diameter side open end 12 are different. Is illustrated.

  Incidentally, if the taper tube to be manufactured is of a straight shape in which the shaft core 10 is not shaken, it is considered relatively easy to bend from a single blank. That is, for example, a straight taper tube can be obtained by rounding a substantially fan-shaped blank (part of a double concentric circle). However, it is extremely difficult to form a taper tube (an irregularly curved taper tube 1) in which the shaft core 10 is variously bent three-dimensionally from a single blank material, in terms of shape reproducibility and profitability. There was no actual manufacturing method that could withstand mass production. In the present invention, even such a deformed curved taper tube 1 can be actually mass-produced from a single blank B.

Further, in the deformed curved taper tube 1 of the present invention, a portion between the small-diameter side open end 11 and the large-diameter side open end 12 serves as a transfer portion 13, which corresponds to the transfer length of the exhaust gas G passing through the taper tube. To do. Note that the length of the transfer portion 13 is substantially equal to the length of the shaft core 10.
Furthermore, in the present invention, since the blank material B is rounded and formed into a tapered tubular shape, the edges of the blank material B are abutted so as to be substantially along the longitudinal direction (axial core 10) of the tube, It is joined by brazing, welding, or the like, and this is referred to as an edge joining portion 14.

Further, due to the fact that the shaft core 10 is bent in various directions, the irregularly bent tapered tube 1 has a surface portion that is relatively tightly bent in appearance, and this portion is a strong bend portion 15. The strong bend portion 15 is usually present at one place in one taper tube, but it is not always necessary to have one place, and two or more places may be present in one taper tube.
Further, the portion where the tube surface becomes substantially flat in the longitudinal direction of the tapered tube is defined as a substantially flat portion 16, where it is preferable that the surface of the tapered tube has almost no bend, but even if there is a bend, it is relatively gentle. If so, this is the substantially flat portion 16. And it is preferable to set (form) the edge joining part 14 mentioned above on this substantially flat part 16, and this will butt | match the edges of the blank material B more reliably, and performs subsequent brazing etc. It is the structure for making it easy. Further, by adopting such a configuration, shape reproducibility is improved, and a desired tapered tube shape can be stably reproduced at a high level.

The irregularly curved tapered tube 1 of the present invention has the above basic structure, and a method for manufacturing the irregularly curved tapered tube, which is the method of the present invention, will be described below.
(1) Blank material preparation step This step is a step of preparing a blank material B as a starting material for the irregularly bent taper tube 1 and, in fact, has an appropriate developed shape from a substantially constant thickness metal plate. Generally, blank material B is punched and prepared. At this time, the blank B naturally has a small-diameter side development length L11 that realizes the small-diameter side opening end 11, a large-diameter side development length L12 that realizes the large-diameter side opening end 12, and a transfer length L13 that realizes the transfer unit 13. It is blanked to the developed shape. Specifically, as shown in FIG. 3, the unfolded shape is punched into a deformed fan shape and has a small-diameter-side unfolded length L11 and a large-diameter-side unfolded length L12 as two opposing arcs, generally separated by a transfer length L13. Presents. In addition, in the said FIG. 3, the code | symbol of S is attached | subjected to the edge of the blank material B which receives butt | matching after this.

(2) U bending process This process is an initial stage of the bending process, and is a process of bending the flat blank material B described above into a U-shaped cross section. In performing this process, as shown in FIG. 4 as an example, the blank material B is press-molded by a U-bending opposed mold 2 including a U-bending punch 21 and a U-bending die 22.
In this case, according to the present invention, the strong bend portion 15 of the tapered tube is firmly sandwiched between the U-bending punch 21 and the U-bending die 22 to realize the shape. In general, it is difficult to form a portion with a large bend (strong bend portion 15) in a desired shape. Therefore, at the initial stage of the bending process, such a portion is formed on both sides with a punch and a die. And is surely formed into a desired shape. In this type of pressing device, the die is usually installed on the lower side, and the punch is provided so as to be movable up and down (pressable), so that the strong bend portion 15 of the tapered tube is positioned on the lower side. The blank structure B is sandwiched from above and below by the U-bending punch 21 and the U-bending die 22 to realize the shape of the strong bend portion 15 more faithfully. Incidentally, FIG. 4 shows a mold structure in which the strong bend portion 15 is positioned on the lower side in a state where the deformed curved taper tube 1 press-molded by the U-bending opposed mold 2 is viewed from the side. 4 and 5, (a) is a perspective view showing a three-dimensional shape of the blank material B after undergoing each process, and (b) is a cross-sectional view showing an example of a facing type necessary for performing each process. It is.

For this reason, in a normal U-bending press, the center part of the blank material B is often the center (center) of the U-bend, but in the present invention, the center part of the blank material is the center of the U-bend. (Refer to blank material B shown in FIG. 4).
In FIG. 4, the U-bending process is illustrated as if it is completed by a single press operation. However, depending on the degree of bending of the strong bend portion 15, the performance (pressing ability) of the pressing device, etc. There may be no problem even if a plurality of bending facing molds 2 are used and the U-bending step is performed in several press operations.
Moreover, the blank material B will be in the state by which both edge S was raised with respect to the strong bend part 15 in the step which received this U bending process.

(3) Round bending process This process is a process of rounding the blank material B after the U bending process into a circular cross-section and the like and bringing both end edges S into contact with each other. In performing this process, as shown in FIG. 5 as an example, press molding is performed by a round bending opposing mold 3 including a round bending punch 31 and a round bending die 32.
Here, the above-described process of matching both end edges S is conventionally described as a “round bending process”, but this is because the section is usually rounded into a circular shape. Therefore, the cross section of the taper tube to be formed does not necessarily have to be circular (round), and can be, for example, a rectangular cross section such as an oval or a quadrangle, or from one opening end side to the other. It is also possible to gradually change the cross section from a circular shape to a rectangular shape toward the opening end side.

Moreover, in order to implement this round bending process, as mentioned above, it is preferable to set the both-ends edge S of the blank material B (end edge junction part 14) to the substantially flat part 16, and to carry out. As a result, the edge joining portion 14 is formed as a locus that is almost linear, such as a relatively gentle curve or a simple broken line, and the end edges S can be more reliably matched. Needless to say, the end edges S can be butt-matched, so that it becomes easy to perform joining such as brazing and welding, which is applied to this portion, and a desired tapered tube shape can be realized at a high level.
Note that FIG. 5 also shows the deformed bent taper tube 1 press-molded by the opposed mold in a state viewed from the side.

Further, at the time of the round bending process, in order to further improve the reproducibility of the shape, it is possible to insert a cored bar (mandrel) inside the blank material B and perform press molding. In particular, when using a taper tube as part of the exhaust pipe, the opening end is often connected to other members such as a muffler. It is preferable that the material B is press-molded so as to be wound, and the opening end serving as the connecting portion is reproduced to have a desired shape, dimensions, and the like, thereby improving the assembling property (fitting property) with the later muffler and the like.
In this round bending process, it is possible to divide into several press operations as in the U bending process.

(4) Joining process of edge joint part This process is a process of joining both edges S that have been matched in the round bending process by brazing, welding, or the like, and blank material B (blank material B at this stage Brazing or the like is performed so as to be along the longitudinal direction of the substantially curved curved taper tube 1 (which has a three-dimensional shape). At this time, if the end edges S are abutted (contacted) in the round bending process, this brazing is very easy and a desired tapered tube shape can be realized at a high level.
The irregularly bent tapered tube 1 of the present invention is not necessarily limited to application to an exhaust pipe, but can be applied to various members such as a hopper for raw material input in various manufacturing apparatuses, a liquid flow pipe, a wind instrument, and the like. Can be applied.

It is the perspective view which shows the use condition which applied the irregular-shaped taper pipe of this invention, and this as an exhaust pipe. It is the front view and top view of an irregular curve taper pipe of the present invention. It is an expanded view which shows an example of the planar expansion | deployment shape of the blank material used as a starting material when manufacturing a deformed curved taper pipe. It is the perspective view (I) which shows the external appearance shape of the blank material which received the U bending process, and explanatory drawing (B) which shows the U bending type which performs this process. It is the perspective view (I) which shows the external appearance shape of the blank material which received the round bending process, and explanatory drawing (B) which shows the round bending die which performs this process. It is a perspective view which shows the irregular curve taper tube formed by the conventional method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Profile bending taper pipe 2 U bending opposing type 3 Round bending opposing type 10 Axle core 11 Small diameter side opening end 12 Large diameter side opening end 13 Transfer part 14 Edge joint part 15 Strong bend part 16 Flat part 21 U bending punch 22 U-bending dies 31 Round-bending punch 32 Round-bending dies B Blank material G Exhaust gas L11 Small-diameter side developed length L12 Large-diameter side developed length L13 Transfer length P Short tubular member S Edge (of blank material)

Claims (4)

In manufacturing a deformed curved taper tube (1) having a small-diameter side open end (11) and a large-diameter side open end ( 12) , and the shaft core (10) being bent or curved three-dimensionally,
This deformed curved taper pipe (1) is a blank material (B) that forms a non-axisymmetric deformed fan shape as a starting material, and this blank material (B) is punched (21, 31 ) And dies (22, 32) as a main component and bent by an opposing mold (2, 3) to form a desired tapered tube shape,
When bending the blank material (B) into a U-shaped cross section , the strong bend portion (15) in the completed shape of the tapered tube is formed without using the center portion of the blank material (B) as the center of U-bending. The strong bend (15) is sandwiched from both sides by the die (22) and punch (21), and the shape of the strong bend (15) is the blank material (B ) at the initial stage of the bending process. ) , A method for manufacturing a deformed curved taper tube.
After the U-bending process, in the bending process of joining both end edges (S ) of the blank material (B) , the edge joining part (14) that becomes the mating part is formed as a relatively flat substantially flat part in the finished shape of the tapered tube. The method of manufacturing a deformed bent taper tube according to claim 1, wherein the method is set to (16) .
3. The deformed bent taper tube according to claim 2, wherein in the bending step of aligning both end edges (S ) of the blank material (B) , a cored bar is inserted into the open end and pressed. Production method.
In a tapered tube having a small-diameter side open end (11) and a large-diameter side open end ( 12) , and the shaft core (10) is three-dimensionally bent or curved, the taper tube has a non-symmetrical shape. 4. A deformed curved taper pipe, wherein one blank material (B) forming a certain deformation fan shape is bent by the manufacturing method according to claim 1, 2 or 3 to be formed into a desired taper pipe shape. .

Images