JP2517830B2 - Elbow molding method using metal pipe - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an elbow with a bent pipe having a small radius of curvature, that is, an elbow made of a metal pipe such as a stainless pipe, a copper pipe, or a steel pipe.

[0002]

2. Description of the Related Art As a conventional technique, as shown in FIG.
There has been a pipe bender 2 in which a longitudinal middle portion 1a of a stainless steel pipe 1 cut into a predetermined size is curved. That is, in the pipe bender 2, an arm 6 is rotatably connected to a shaft center portion of a large-diameter forming roll 3 having a groove 3a having a semicircular cross section on its outer periphery via a pin 5 so that the arm 6 can rotate. A pressure roller 4 having a small diameter and having a groove 4a having a semicircular arc shape in the outer periphery is formed at an intermediate portion in the longitudinal direction of 6 by a pin 7 so as to be rotatably connected to the pressure roller 4.
Is circumscribed on the forming roll 3 and the straight pipe 1 is inserted between the grooves 3a and 4a of the forming roll 3 and the pressure roll 4, and the left end portion of the pipe 1 is covered by a stopper 8
6, the pressure roll 4 is rotated in the direction of the arrow (a) in FIG. 6 via the arm 6, and the longitudinal middle portion of the pipe 1 is curved along the groove 3a of the forming roll 3, 7
The curved pipe 1-1 as shown in FIG.

[0003]

In the above-mentioned conventional apparatus, since the pipe 1 is clamped and curved by the forming roll 3 and the pressure roll 4, the radius of curvature R of the axis L of the pipe 1 is set.
It cannot be made smaller than the diameter dimension D, and there is a drawback that the space of the pipe increases. As a countermeasure against this, there is a means for forming an elbow made of a metal pipe having a small radius of curvature by cutting the end faces of a pair of pipes at an angle of, for example, 45 degrees with respect to the axis and connecting the end faces with each other by welding. However, this requires a high level of welding technology and has a drawback that productivity becomes poor. An object of the present invention is to obtain a new method for forming an elbow with a metal pipe, which solves the above-mentioned drawbacks.

[0004]

The present invention is configured as follows to achieve the above object. That is, the longitudinal middle portion of the metal pipe is curved with a radius of curvature such that the radius of curvature of the axis of the pipe is equal to or larger than the diameter of the pipe, and the longitudinal middle portion has a radius of curvature substantially equal to the diameter of the pipe. A mold having a groove having a semi-arcuate cross-section that is curved in a valley shape and fits a semi-circumferential portion of the pipe is provided, and the curved pipe is fitted into the molding groove of the mold and the length of the curved pipe is long. A pair of rod-shaped forming rods, whose both ends in the direction are pressed and locked to both ends of the forming groove by clamps, and whose tips are formed in an arc surface approximately equal to the radius of curvature in one longitudinal direction of the curved portion of the forming groove, A forming punch having a fitting groove having a semicircular arc cross section which is curved in a sharp mountain shape facing the middle portion of the forming groove and which fits a half peripheral portion of the pipe, and the forming rods are provided at both ends of the bending pipe. In the longitudinal direction Parts are moved toward each molded rod (1
Rutotomoni butt tip comrades 4) is obtained by the configuration in which the pressing bending a longitudinally intermediate portion of the curved pipe by said forming punch toward the longitudinally intermediate portion of the forming groove.

[0005]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 4 show the main manufacturing steps according to the present invention. First, as shown in FIG. 1, the left and right (longitudinal) direction intermediate portion 1a of a stainless steel pipe 1 cut into a predetermined size is bent by a pipe bender 2, and as shown in FIG. The radius R of curvature of the axis L of the portion 1a is substantially equal to the diameter dimension D of the pipe 1, and the curved pipe 1-1 is formed such that the intersection angle α of the left and right end portions 1b and 1c is, for example, 90 degrees. The formation of this curved pipe 1-1 is
It is formed in the same manner as the above-mentioned conventional method. In FIGS. 1 and 2, the same reference numerals as those in FIGS. 6 and 7 have the same structure as those in FIGS. 6 and 7, and therefore the description thereof will be omitted.

Next, as shown in FIG. 3, the curved pipe 1-1 is fitted and locked in a molding groove 11 formed in an elongated shape in the left-right direction on the upper surface of the mold 10 and having a valley shape in a side view. This forming groove 1
1, the curvature radius R1 of the bottom surface of the left-right (longitudinal) direction intermediate portion 11a is substantially equal to the diameter dimension D of the curved pipe 1-1, and the intersection angle β of the left and right end portions 11b and 11c is the curved pipe 1- 1 is formed at an angle (90 degrees) with the crossing angle α of the left and right ends 1b and 1c of the pipe 1, and the cross-sectional shape is formed into a semi-circular shape that fits the lower half of the pipe 1-1. The curved pipe 1-1 is fitted and locked in the groove 11 with the left-right direction intermediate portion 1a thereof facing downward.

Next, the left and right (longitudinal direction) end portions 1b and 1c of the curved pipe 1-1 are pressed and locked to the left and right end portions 11b and 11c of the molding groove 11 by a pair of left and right clamps 12. The clamp 12 has a holding groove 12a having a semi-circular cross section, which fits the upper half portions of the left and right end portions 1b and 1c of the curved pipe 1-1 in the lower portion, and is moved and held downward by the first cylinder 13. Left and right ends 1 of the curved pipe 1-1 in the groove 12a
The upper half portions of b and 1c are fitted, and the left and right end portions 1b and 1c are pressed and locked to the left and right end portions 11b and 11c of the molding groove 11.

Left and right ends 11b, 11 of the molding groove 11
A pair of rod-shaped forming rods 14 are arranged to face each other in c, and the right and left end portions 11b, 11b
11c is moved in the opposite direction. The forming rod 14 has the lower surface of each tip 14a on the opposite side formed into an arc surface substantially equal to the radius of curvature R1 of one bottom surface of the left-right direction intermediate portion 11a of the forming groove 11. Further, the forming punch 16 having the fitting groove 17 in the lower portion is arranged above the intermediate portion 11a of the forming groove 11 and is moved vertically by the third cylinder 18. The fitting groove 17 is the intermediate portion 11 of the molding groove 11.
The bottom surface 17a of the middle portion in the left-right (longitudinal) direction which is curved in a mountain shape facing a is formed to have a radius of curvature of 2 mm to 3 mm, and the cross section is formed in a semi-arcuate shape to fit the upper half of the pipe 1-1. To do.

As shown in FIGS. 3 and 4, the second cylinders 15 synchronize the molding rods 14 to move the molding rods 14 toward the center in the left-right direction. Left and right ends 1b and 1c of -1
And the molding punch 16 is moved downward by the third cylinder 18 to press the left-right intermediate portion 1a of the bending pipe 1-1 along the left-right intermediate portion 11a of the forming groove 11, that is, draw forming. Then, as shown in FIG. 5, the radius of curvature R2 of the lower surface of the intermediate portion 20a is equal to the diameter D of the pipe 1-1.
And the radius of curvature of the upper surface of the intermediate portion 20a is 2 mm
An elbow 20 having a size of 3 mm is formed. According to the above example
If so, the curved pipe 1-1 has a curved portion (longitudinal middle).
The radius of curvature R of the axis L of the portion 1a) is equal to or less than the diameter D of the pipe 1.
Since it is above, it can be easily formed with the conventional pipe bender 2.
be able to. The elbow 20 is the curved pipe 1 described above.
The outside of the curved portion of -1 is the tip portion 14a of each forming rod 14.
By the curved portion of the molding groove 11 (longitudinal intermediate portion 11a)
By pressing and bending along, that is, draw forming,
The radius of curvature on the outside of the intermediate portion 20a is approximately equal to the diameter D of the pipe
The curved portion of the curved pipe 1-1 formed on R2.
Is the sharp tip of the forming punch 16 (the middle in the longitudinal direction).
The portion 17a) pushes the molding groove 11 toward the curved portion.
By press-bending, that is, by drawing, the intermediate portion 20a
Is formed with a much smaller radius of curvature than the outside
It will be.

[0010]

As is apparent from the above description, the present invention
The elbow made of metal pipe molded by
Since the radius of curvature of the bent portion becomes small, a mounting flange can be provided in the vicinity of the bent portion, and piping can be performed in a small space. In particular, exhaust manifolds, intake manifolds, etc. of automobile engines can be formed from pipe materials made of heat-resistant metal such as stainless steel, which is suitable for weight reduction. Also, ahead
The end is approximately equal to the radius of curvature on one side in the longitudinal direction of the curved part of the forming groove.
A pair of rod-shaped forming rods formed on a new arc surface
The curve is moved by moving it toward the center in the longitudinal direction in the curved pipe.
While drawing the outside of the curved part of the pipe to a small diameter,
Form a forming punch curved into a sharp chevron in the longitudinal direction of the forming groove.
Inside the curved part of the curved pipe by moving it toward the interspace
Since it is designed to be drawn to a small diameter, wrinkles, cracks, etc.
Getting an elbow with a small radius of curvature without occurring
Can be. Furthermore, use the above-mentioned forming rod and forming punch
And formed by drawing so that the radius of curvature of the bent portion becomes smaller.
Therefore, if the molding device is small, simple, and cheap,
Both have effects such as high productivity.

[Brief description of drawings]

FIG. 1 is a side view showing a first step of the present invention.

FIG. 2 is a side view of a curved pipe formed by the first step of the present invention.

FIG. 3 is a side sectional view showing a second step of the present invention.

FIG. 4 is a side sectional view showing a third step of the present invention.

FIG. 5 is a side view of an elbow formed by the third step of the present invention.

FIG. 6 is a side view showing a conventional process.

FIG. 7 is a side view of a curved pipe formed by a conventional process.

[Explanation of symbols]

 1 Pipe 1a Left-right (longitudinal) direction middle part 1b Left end part 1c Right end part 1-1 Curved pipe 2 Pipe bender 3 Forming roll 3a groove 4 Pressure roll 4a groove 5 pin 6 Arm 7 pin 8 Stopper 10 Type 11 Forming groove 11a Left and right (Longitudinal) direction middle part 11b Left end part 11c Right end part 12 Clamp 12a Holding groove 13 First cylinder 14 Forming rod 14a Tip part 15 Second cylinder 16 Forming punch 17 Fitting groove 17a Left and right (longitudinal) direction middle part 18 Third cylinder 20 Elbow 20a Middle part

Claims (1)

(57) [Claims] 1. A radius of curvature (R) of an axial line (L) of the pipe (1) made of a metal is equal to or larger than a diameter (D) of the pipe (1). A cross-section half which is curved and curved in a valley shape with a radius of curvature (R1) of the intermediate portion (11a) in the longitudinal direction substantially equal to the diameter (D) of the pipe and which fits a half circumference portion of the pipe (1). A mold (10) having an arc-shaped forming groove (11) is provided, and the curved pipe (1-1) is fitted into the forming groove (11) of the mold (10) and the curved pipe (1) −
1) clamp both ends (1b, 1c) in the longitudinal direction.
2) Both ends (11b, 11c) of the forming groove (11)
Is pressed and locked to the molding groove (11) at the tip (14a).
Of a pair of rod-shaped forming rods (14) formed in an arc surface substantially equal to the radius of curvature of one of the curved portions of the curved portion of the curved portion, and curved in a sharp mountain shape facing the intermediate portion (11a) of the forming groove (11). And a forming punch (16) having a fitting groove (17) having a semi-circular cross section for fitting a semi-circular portion of the pipe, and each forming rod (14) is fitted with a bending pipe (1-1).
Fit both ends (1b, 1c) of the molding rod and move them toward the center in the longitudinal direction, and stick the tips of the molding rods (14) together.
The combined Rutotomoni, characterized in that by pressing bent toward the longitudinally intermediate portion (11a) of the longitudinally intermediate portion (1a) forming groove of the curved pipe (1-1) (11) wherein the forming punch (16) Molding method of elbow with metal pipe.