JPH0730186Y2 - Pipe material forming equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a pipe material molding apparatus for press-molding an end portion of a pipe material into an irregular cross-sectional shape.

(Prior Art) In recent years, in the field of automobiles, in order to reduce the weight of an engine and to reduce the cost, an exhaust manifold of an engine, which is conventionally generally formed integrally with a casting, is mounted on a steel plate as shown in FIG. With the flange 52, the independent exhaust pipes 51, 51, ... Made of a pipe material are joined, and the downstream ends 51a, 51a, ... Of the respective independent exhaust pipes 51, 51 ,. Is being attempted. A main exhaust pipe (not shown) composed of a single pipe is fitted and connected to the collecting portion 53 of the exhaust manifold 50.

As described above, in order to collect a plurality of independent exhaust pipes 51, 51, ... And connect them to the main exhaust pipe having a circular cross section, for example, in an exhaust manifold for a four-cylinder engine, each independent exhaust pipe is independent. The ends of the exhaust pipes 51, 51, ... Are shown in FIGS.
As shown in the figure, two plane parts 54, 55 that are adjacent to each other in an orthogonal state
It is necessary to form a substantially fan shape including the circular arc portion 56 and the independent exhaust pipes 51, 51, ... so that the outer shape of the collecting portion 53 becomes circular. And, in this case, if the flatness of each flat portion 54, 55 of each independent exhaust pipe 51, 51, ...
..Independent exhaust pipes 51, 51 adjacent to each other when combined
A gap is generated between the surface portions that abut each other, resulting in gas leakage or the like, which is not preferable.

As a method of forming the collecting portion 53 in such an exhaust manifold made of a pipe material, there is, for example, a method disclosed in Japanese Utility Model Laid-Open No. 60-60113.

In this known example, as shown in FIG. 10, four circular pipe ends of four pipe members 60, 60, ... Each pipe material 60, 60,
The outer peripheral side of the pipe member 60, which has a substantially V-shaped forming surface 63 at its tip side and has a first forming die 61 inserted and arranged inside the pipe member 60, and an arc-shaped forming surface 64. Assembling the second molding die 62 arranged in the
Each of 61 and 62 can be pressed toward the center of the assembly. The pair of molding dies 61 and 62 have a separate structure and can be independently moved.

Then, by simultaneously moving these molding dies 61, 62 toward the center of the collecting portion, the pipe ends of the pipe members 60, 60, ... Are press-molded into a substantially fan-shaped cross section.

In this case, the pair of molding dies 61 and 62 are arranged such that, from the state shown in FIG. 10, the outer second molding die 62 is moved in the direction of the arrow by the pressing device (not shown) to the outer peripheral side of the pipe material 60. To start molding. The inner peripheral surface of the pipe material 60, which is deformed due to the progress of molding by the second molding die 62, is the outer end surface 61 of the first molding die 61.
When it comes into contact with a, it moves integrally with the second mold 62 as if it were pushed by the first mold 61 and the second mold 62. Molding proceeds with the movement of the first and second molding dies 61, 62,
Finally, as shown in FIG. 11, the pipe members 60, 60, ... Are formed into a substantially fan shape with their pipe ends in contact with each other, and the outer peripheral surface is formed into a circular gathering portion 53. .

(Problems to be solved by the device) However, such a method has the following problems.

(1) At the start of molding, that is, only the second molding die 62 is the pipe material 60.
During the molding process from the time when the pipe material 60 is contacted with the outer peripheral side of the pipe material 60 until the molding by the first molding die 61 is completed, the pipe materials 60, 60 ,. Since the outer peripheral surfaces near the center of the part are only in contact with the adjacent pipe materials 60, there is no guide for the deformation due to the molding of this part, so the deformation state of each pipe material 60, 60 Uneven, flat surface 54,55 after molding is completed
There is a risk that the flatness accuracy of the device will decrease, and as a result, a gap will be created between the adjacent surface portions, leading to gas leakage.

(2) When the end portion of the pipe material 60 having a circular cross section is deformed into a substantially fan shape and these are combined to form the collecting portion 53 having a circular cross section, as shown by the dimension S in FIG. The tops 57 of the flat portions 54, 55 project outward in the radial direction from the outer peripheral surface of the pipe material 60 (shown by a chain line) before molding. In the case where the projecting portion is projected from the original shape and the projecting portion is pointed like this, a so-called back state occurs in which the projecting portion is pulled back by elastic deformation when the molding die is removed after molding.

For this reason, as shown in FIG. 12, when forming a mold, the mold is not normally manufactured to match the original required shape (shown by the solid line). It is manufactured according to the shape at the time of completion of molding with anticipation of the back allowance, and during the actual molding operation, the molding die is pushed a little larger than the original molding position to cause excessive deformation, and the required shape in the state where the back occurs after molding. Is being obtained.

However, in the case of the configuration in which the molding dies are fed simultaneously from all four directions as in this known example, the molding in consideration of the back allowance cannot be performed, and as a result, the flat portions 54, 55 of the pipe members 60, 60, ... They cannot be brought into close contact with each other and cause gas leakage.

(3) The first molding die 61 punches through the peripheral wall of the pipe material 60.
Since it is pressed by 62, when there is a variation in the wall thickness dimension of this peripheral wall, a difference occurs in the relative dimension between the first molding die 61 and the second molding die 62, and the molding accuracy of the pipe material 60. Will be adversely affected.

Therefore, in the present invention, the end portions of the pipe materials to be assembled together are individually and accurately press-formed to ensure the accuracy in the assembled state, and a suitable pipe material forming apparatus therefor is provided. That is the purpose.

(Means for Solving the Problem) In the present invention, as a specific means for solving the problem, the end portion of a pipe material having a circular cross section is formed by a press molding die at a predetermined angle. The cross-section has a substantially triangular shape having two adjacent flat portions and an arc portion connecting these two flat portions, and the apex portions of the two flat portions are projected outward from the outer circumference of the pipe material. Further, in a pipe material molding apparatus for molding the arc portion so as to be recessed inward from the outer periphery of the pipe material, the press mold has a substantially V-shape for molding the outer peripheral surfaces of the two flat portions. A die having a molding surface and a substantially V that can be fitted to the molding surface of the die
It has a convex molding part that has a V-shaped molding surface and can be inserted inside the pipe material, and a molding surface that is spaced apart from the convex molding part on the side opposite to the molding surface and that molds the arc portion. A concave forming part is integrally formed with a punch, and the punch is movable in the contacting and separating direction with respect to the die with the convex forming part facing the forming surface of the die. At the same time, the distance between the apex of the convex molding portion and the top of the concave molding portion in the moving direction of the punch is set to be smaller than the outer dimension of the pipe material.

(Operation) Since the present invention has such a configuration, (1) as illustrated in FIG. 5, the end portion of the pipe material 30 is placed on the substantially V-shaped molding surface 21 of the die 11 and The punch 12 is arranged at the end of the pipe material 30, the convex molding portion 14 is arranged inside the pipe material 30, and the concave molding portion 13 is arranged on the outer peripheral surface side of the pipe material 30. By bringing the portion 13 into contact with the outer peripheral surface of the pipe material 30, the outer peripheral surface of the pipe material 30 is supported at three positions in the circumferential direction,
The convex forming part 14 is not in contact with the inner peripheral surface of the pipe material. (2) By pressing the punch 12 toward the die 11, first the forming between the die 11 and the concave forming part 25 of the punch 12 is performed. The action is started, and the pipe material 30 is gradually deformed on both upper and lower sides along the molding surfaces of the die 11 and the punch 12 while gradually moving toward the die 11 side as shown in FIG. It is deformed into a substantially elliptical shape, and the top portion 14b of the convex shaped portion 14 of the punch 12 is brought into contact with the inner peripheral surface of the pipe material 30 accordingly. (3) When the punch 12 is further pressed, The die 11 side portion is smoothly pushed by the pushing action of the concave shaping portion 13 of the punch 12 to the die 11 side and the overhanging action of the convex shaping portion 14 (4) The punch 12 is When reaching a predetermined position, as shown in FIG. 7, the molding surface of the die 11 and the convex surface of the punch 12 are projected. Shaped part 14
And two planar parts 33, 3 that are continuous with a certain included angle.
4 and the circular arc portion 35 is formed by the concave forming portion 13 of the punch 12 (effect of the invention). Therefore, according to the pipe material forming apparatus of the present invention, (1) the end of the pipe material 30 is The die 11 and the punch can be formed without irregular deformation during forming.
While being guided by the molding surface of 12, the molding of the flat surface portions 33, 34 is performed while bringing the meat of the pipe material 30 from the arc portion 35 side to the flat surface portions 33, 34 side. Even though 34 has a substantially V-shaped cross-sectional shape, its molding can be performed smoothly and accurately, and a higher level of molding accuracy can be secured. (2) Two flat surface portions 33, 34 Since the forming is performed by the forming surface of the die 11 and the punch 12, the die 11 and the punch 12 are
And can be designed and manufactured in consideration of the backing cost after molding, and it is easy to ensure product accuracy, and so on.

(Embodiment) A preferred embodiment of the present invention will be described below with reference to FIGS. 1 to 7.

FIG. 1 shows a pipe material forming apparatus Z according to an embodiment of the present invention. This pipe material forming device Z is for individually forming each of the independent exhaust pipes 51, 51, ... Constituting the exhaust manifold 50 for a 4-cylinder engine as shown in FIG. As shown in FIG. 4 (A),
A pipe end 30 of a pipe material 30 that is bent and formed into a predetermined shape in advance.
By subjecting a to a press forming process, as shown in FIG. 4 (B), a pipe molded body 31 is formed in which the pipe end portion is a deformed portion 32 having a substantially fan-shaped cross-sectional shape. In addition, this deformed portion 32
Is an exhaust manifold together with the other three similarly shaped pipe moldings 31, 31, 31 (not shown), as shown by the chain line in FIG. The main exhaust pipe connecting portion 36 having a circular outer peripheral surface is formed by abutting the respective pipe molded bodies 31, 31 ,.

The deformed portion 32 is a deformed portion of another pipe molded body 31.
For the sake of abutting against 32, it has two plane portions 33 and 34 which are continuous with each other at an included angle of 90 °, and an arc portion 35 which connects them. Further, the fact that the tops 37 of the two flat portions 33, 34 project outward from the outer peripheral surface of the pipe material 30 before molding, and that the arcuate portion 35 is recessed inward from the outer peripheral surfaces are as described above. This is the same as the case of the conventional example.

As shown in FIGS. 1 and 3, the pipe material forming apparatus Z includes a press forming die 1 including a die 11 and a punch 12 described later. The die 11 is fixedly arranged on the base 2, and has a V-forming surface 21 having an included angle of 90 ° and a die 11 which is continuous and axially rearward of the V-forming surface 21. A forming surface 20 formed of a taper forming surface 22 having a curvature capable of being inscribed therein, and an arcuate supporting surface 23 continuous to the rear side of the forming surface 20 and having the same curvature as the pipe member 30. is doing.

Above the arc-shaped support surface 23 of the die 11, as shown in FIGS. 1 and 2, by abutting with the arc-shaped support surface 23, a cylinder having substantially the same diameter as the pipe material 30 is formed. A pressing die (15) having an arcuate support surface (24) forming a space is arranged so that it can come into contact with and separate from the die (11). Further, a predetermined supporting pressure is applied to the pressing die 15 by the pressing device 42.

The punch 12 has a concave shaped portion 13 composed of a protrusion having an arc shaped molding surface 25, and a V forming shaped surface 26 having a substantially triangular cross section and having a 90 ° included angle at its base end. Also, the tip end side is integrally formed with a convex shaped portion 14 constituted by a projection body in which an arcuate tapered shaped surface 27 is formed.

The concave molding portion 13 and the convex molding portion 14 have their respective molding surfaces directed toward the V-forming surface 21 side of the die 11,
Moreover, as shown in FIG. 5, the upper surface 14a of the convex shaped portion 14 is
And the top 25a of the arc-shaped molding surface 25 of the concave molding portion 13 have a dimension l ₁ into which the peripheral wall of the pipe material 30 can be inserted, and the top 25a of the arc-shaped molding surface 25 and the V-forming surface 26 The relative position of the pipe member 30 is set so that the distance l _{2 from} the apex 26a becomes smaller than the outer dimension of the pipe member 30. The punch 12 is fixed to a movable member 4 which can be vertically moved by a press device 41 so that the punch 12 can be pressed.

Then, using the pipe material forming apparatus Z, the pipe material
An operation for producing the pipe molded body 31 by press molding the end portion of 30 will be described with reference to FIG.

First, as shown in FIG.
Is placed on the arc-shaped support surface 23 of the
And the arcuate support surface 24 (see FIG. 2) of the pressing die 15 are sandwiched and fixed, and the punch 12 is inserted into the end portion of the pipe material 30 and the convex shaped portion 14 is inserted into the pipe material 30. Set in the state. In this state, the convex shaped portion 14 is not in contact with the pipe material 30.

From this state, when the movable member 4 is pushed down by the pressing device 41 and a pressing force is applied to the punch 12, the forming operation by the punch 12 is started. In this case, the pipe material 30 is supported by the concave shaped portion 13 of the punch 12 and the die 11 and is not in contact with the convex shaped portion 14. Therefore, the pipe material 30 is first formed into the arc-shaped forming surface 25 of the punch 12.
It is deformed in a flat direction by the ridge, and is gradually pushed toward the die 11 side as a whole, and when a predetermined amount of deformation is reached, as shown in FIG.
b, that is, the apex 26a of the V-shaped surface 26 abuts on the inner peripheral surface of the pipe material 30.

When the punch 12 further descends from this state and the molding proceeds, the arcuate molding surface 25 of the concave molding portion 13 pushes the pipe material 30 toward the V-forming surface 21 side of the die 11 and the convex molding portion 14 V of die 11 of pipe material 30 by V forming surface 26 of
The projecting action to the forming surface 21 side is performed at the same time, and the forming of the circular arc portion 35 by the concave forming portion 13 and the forming of the flat surface portions 33, 34 by the convex forming portion 14 simultaneously proceed.

Finally, as shown in FIG. 7, when the convex shaped portion 14 reaches the lowermost position, the forming is completed, and the deformed portion 32 having a substantially fan-shaped cross section is obtained.

As described above, in the pipe material molding apparatus Z of this embodiment, since the press molding of the pipe material 30 is always performed while being supported by the molding surfaces 25, 21, and 26, it is irregular during molding. There is no deformation and the molding accuracy is improved.

In the middle of molding, since the pipe material 30 is entirely pushed toward the V-forming surface 21 side of the die 11 by the concave molding portion 13 of the punch 12, the projecting work of the pipe material 30 by the convex molding portion 14 is performed. As a result, the pipe member 30 can be smoothly moved to the projecting side, the molding accuracy of the flat portions 33 and 34 is improved, and the flatness thereof is increased.

Further, as in this embodiment, the V of the die 11 that abuts each other.
Forming surface 21 and V forming surface 26 of convex forming portion 14 of punch 12
In the configuration in which the plane portions 33 and 34 are formed by and, when setting the shapes of the V-forming surface 21 and 26 as described above,
The bag allowance after the preforming can be expected, and the dimensional accuracy of the product can be further enhanced.

As a result of these, four finished pipe molded bodies 31, 31,
.. are combined as shown in FIG. 8 to form an exhaust manifold, the dimensional accuracy of the deformed portion 32 of each pipe molded body 31 is high and the flatness of the flat portions 33, 34 is good. Exhaust manifold main exhaust pipe connection 36 (4th
While the circularity and the diametrical dimension shown in FIG. (B) are properly maintained, there is almost no gap at the connecting portion between the pipe molded bodies 31, 31 ,. Therefore, when this is used for an engine, there is no risk of gas leakage, and the reliability and commercial value of the product can be improved.

In this embodiment, the press device 41 for driving the movable member 4 and the press device 42 for driving the pressing die 15 are separate bodies, but in another embodiment of the present invention, this is a single press device. You can also do it in. However, in this case, a means for preventing an excessive pressing force from being applied to the pressing die 15, for example, a rubber member having a predetermined elastic force is interposed between the pressing device and the pressing die 15. Measures are needed.

Further, in this embodiment, the molding of the exhaust manifold for a 4-cylinder engine in which four pipe molded bodies 31 are combined has been described, but the present invention is not limited to this and is widely applicable to a multi-cylinder engine. Of course, it can be applied to the molding of an exhaust manifold.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a main part of a pipe material forming apparatus according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view of II-II in FIG. 1, and FIG. 3 is a longitudinal sectional view of III-III in FIG. FIG. 4 (A) is a perspective view of a pipe material, FIG. 4 (B) is a perspective view of a pipe molded body, and FIG.
Figures 7 to 7 are explanatory views of the molding state, FIG. 8 is a perspective view of the exhaust manifold, FIG. 9 is a view taken along the arrow IX of FIG. 8, and FIGS. 10 and 11 are explanatory views of the molding state according to the conventional method. FIG. 12 is an explanatory view of the back allowance of the molding die. 1 …… Press molding die 4 …… Movable member 11 …… Die 12 …… Punch 13 …… Concave molding part 14 …… Convex molding part 33,34 …… Plane surface 35 …… Arc part

Claims (1)

[Scope of utility model registration request] Claims: 1. A pipe material having a circular cross section and having an end portion formed by a press molding die and having two plane portions adjacent to each other with a predetermined included angle and an arc portion connecting the two plane portions. Molded into a triangular irregular cross-sectional shape, with the apex portions of the two flat portions projecting outward from the outer periphery of the pipe material and the circular arc portion being recessed inward from the outer periphery of the pipe material. In the pipe material molding apparatus, a die having a substantially V-shaped molding surface that molds the outer peripheral surfaces of the two flat portions, and a substantially V shape that can be fitted to the molding surface of the die. It has a convex molding part that has a V-shaped molding surface and can be inserted inside the pipe material, and a molding surface that is spaced apart from the convex molding part on the side opposite to the molding surface and that molds the arc portion. And a punch formed integrally with the concave shaped portion, and The shape-forming part is made movable in the contact and separation direction with respect to the die in a state of being opposed to the forming surface of the die, and the apex of the convex forming part and the top of the concave forming part in the moving direction of the punch are formed. The pipe material forming apparatus is characterized in that the interval of is set to be smaller than the outer dimension of the pipe material.