JPS635827A - Method and device for bending angular pipe - Google Patents

Abstract

PURPOSE:To perform the bending twisted three-dimensionally for an angular pipe by setting to a roll die and inclining so that its each outer face may not intersect at right angles with and in parallel to the rotary axial line of the roll die and performing the bending of the angular pipe. CONSTITUTION:The guide groove 12 of V shaped cross section abutted to the outer peripheral 2 faces P1, P2 of the inner side of the angular pipe P of the bending object and to which a bending is executed by winding with the inclined state for the rotary axial line l is provided on the outer periphery of a roll die 11. The angular pipe P is set by extending to the tangent direction for the roll die 11 in the inclined state and the prescribed place of the angular pipe P is fixed by holding it with a clamp mechanism 13. The roll die 11 is then rotated and the angular pipe P is fed by setting to the peripheral speed of the outer peripheral face of the roll die 11 and moved as well in the tangent direction with pressing a pressure die 18 to the roll die 11 side. In this way, the three-dimensional bending that each outer face becomes in the shape of the side face of a cone for the angular pipe can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for bending a square pipe used, for example, in the frame of a motorcycle, and a device for bending a square pipe used to carry out the method. It's Shino.

``Conventional technology'' Recently, square pipes have become mainstream instead of round pipes as body frames for motorcycles, but this is because square pipes are more resistant to twisting than round pipes, and This is because if the arrangement is appropriately determined according to the load direction, a large cross-sectional area opposing the load direction can be taken, and its divisibility can be improved.

FIG. 1 shows an example of a conventional motorcycle body frame using square pipes.

This body frame is called a diamond-shaped frame, and from the upper part of the head pipe indicated by reference numeral 1 in the figure, a pair of left and right main pipes 2.2 spread in the left and right direction with the body as a reference, and then extend rearward ( From the lower part of the head pipe 1, a pair of left and right down tubes 3.3 are provided to extend laterally and then diagonally rearward and downward. An engine (not shown) is supported at the rear end of 3.

Conventional square pipes used in the body frame of motorcycles, such as the down tube 3 mentioned above, are, for example,
As described in Japanese Patent No. 50887, the bending process is performed by providing a wedge-shaped notch in the bent portion of the pipe, leaving an outer vertical wall, and then bending the pipe so that both sides of the notch meet and welding. the outer surface 3a of the square vibrator, which is inside and outside with respect to the direction of bending;
3b is bent so as to be parallel to the axis Q, which is the bending center, and outer surfaces 3c and 3d on both sides thereof are bent to be perpendicular to the HgE axis.

``Problem to be Solved by the Invention'' However, with the square pipe bent in this way, when the down tube 3 is joined to the head pipe l, both pipes 113 are inclined to each other, as shown in FIG. angle θ
This results in the following problems: (1) It is difficult to expose the joint surface for welding, making the welding process troublesome; and (2) It is difficult to perform reinforcement using gussets.

For this reason, an angle is formed in which the - end side widens in the left-right direction with the vehicle body as a reference and extends diagonally rearward and downward, and the other end joins the head pipe l so that its longitudinal axis is parallel to the axis of the head pipe l. The appearance of a pipe, or in other words, a three-dimensionally twisted square pipe, has been awaited.

The present invention has been made in view of the above circumstances, and aims to provide a method for bending a square pipe that can be twisted three-dimensionally, and an apparatus suitably used when carrying out this method. .

[Means for Solving the Problems] The method of the present invention involves extending a square pipe having a square cross section in a tangential direction with respect to the roll mold, and at the same time extending a predetermined portion of the square pipe at a predetermined location on the outer periphery of the roll mold. In the square pipe bending method, the rectangular pipe is fed while rotating the roll mold, and the rectangular pipe is rolled along the outer periphery of the roll mold to perform the bending process. It is characterized in that the bending process is carried out by setting it in the roll mold so as not to be perpendicular to or parallel to the rotational axis of the roll mold.

The apparatus of the present invention also includes a roll mold that bends a square pipe having a square cross section while rolling it along its outer periphery as it rotates, and a clamp mechanism that grips and fixes a predetermined portion of the square pipe on the outer periphery of the roll mold. and a pressure mold that presses a bending start portion of the square pipe against the outer periphery of the roll mold against bending reaction force when the roll mold rotates to bend the square pipe, the pipe bending device comprising: On the outer periphery of the mold, there is a V-shaped cross-section that contacts the two outer peripheral surfaces of the square pipe and bends the same square pipe in an inclined state so that the outer surfaces are not perpendicular or parallel to the rotation axis of the roll mold. The clamp mechanism is provided with a locking portion that comes into contact with the outer surface of the square pipe to hold and fix the same square pipe in the inclined state, and the pressure type is further provided with a locking portion that comes into contact with the outer surface of the square pipe to hold and fix the same square pipe in the tilted state. , a pressure surface having a V-shaped cross section is provided which contacts the two outer surfaces and presses the same-angle pipe against the roll shape in the inclined state.

``Operation'' In order to perform the bending process by setting square pipes in a roll mold with their respective outer surfaces inclined so that they are not perpendicular or parallel to the rotational axis of the roll mold, Can perform three-dimensional bending into a conical side shape,
The entire pipe can be twisted three-dimensionally.

"Embodiments" Examples of the present invention will be described below with reference to the drawings.

3 and 4 show a square pipe bending device according to the present invention, which is an improved version of what is commonly called a rotary bender.

The reference numeral 11 in the figure is a roll type, and the outer periphery of the roll type I■ is in contact with two inner peripheral surfaces P, , P of a rectangular pipe P with a square cross section, which is the object to be bent. A guide groove 12 having a V-shaped cross section is formed by winding a square pipe in an inclined state so that each outer surface P, ~P4 thereof is not perpendicular to or parallel to the rotational axis a of the roll mold 11 and is bent.
is provided.

Further, the roll mold 11 is provided with a clamp mechanism 13 that grips and fixes a part of the square pipe P arranged so as to extend in the tangential direction with respect to the roll mold II. The clamp mechanism 13 has a clamp body 14 bolted to the roll type II and a square pipe P sandwiched between the clamp body 14 and a clamp body 14 that is bolted to the clamp body 14 or equipped with a one-touch locking device or the like. The clamp M15 is fixed by a fixing means.

The clamp body 14 and the clamp M15 constituting the clamp mechanism 13 each have a locking surface that comes into contact with each outer surface P, -P of the square pipe P and holds and fixes the square pipe P in the tilted state. 16.17 are provided. The locking surface 17 on the side of the clamp body 14 is continuous with the roll-shaped guide groove 12.

Moreover, 18 is a pressure mold disposed so as to extend in a tangential direction to the roll mold 11 and to be movable in the same direction. This pressure type I8 has an inner square pipe P
When the roll die 11 is rotated to bend the square pipe P, the bending start part of the square tube P tends to move away from the roll die due to the reaction force at that time. It is in charge of regulating. This pressure mold 18 has a pressure surface 1 having a V-shaped cross section that contacts the two outer peripheral surfaces P3 and P4 of the square vibrator P and presses the same square pipe P against the roll mold 11 while holding it in the inclined state.
9 is provided.

Next, a method of bending the square vibrator P using the apparatus having the above configuration will be explained.

First, as shown by the solid line in FIG. 3, the square vibrator P to be bent is tilted so that its outer surfaces P1 to P4 are neither perpendicular nor parallel to the rotational axis Q of the roll die 11. It is set so as to extend tangentially to the roll mold 11, and a predetermined portion of the same square pipe P is gripped and fixed by the clamp mechanism 13.

Next, while avoiding rotation of the roll mold 11, the square pipe P
is fed in accordance with the circumferential speed of the outer peripheral surface of the roll mold 2, and
As shown by the arrow in the figure, the pressure mold 18 is a roll mold l.
It is moved in the tangential direction of the roll mold 11 according to the moving speed of the pipe P while being pressed to the l side. At this time, the square pipe P has the inner outer surface P3, Pt connected to the guide groove 12 of the roll mold 11.
Since it is not guided by the groove 12, it gets caught up in the groove 12 and is bent while remaining in an inclined state.

Further, during the above-mentioned bending process, a core metal (not shown) is inserted from inside the bending start portion of the pipe P to prevent deformation and wrinkles of the pipe P.

The square pipe P shown in FIGS. 5 and 6 is obtained by bending as described above. This pipe P is three-dimensionally bent so that each outer surface P, -P has a conical side surface shape, and the pipe P is three-dimensionally twisted as a whole.

FIGS. 7 and 8 show an example in which a square pipe bent as described above is used in a body frame of a motorcycle.

The downtube indicated by 20 in the figure is bent by the method of the present invention. As shown in the figure, this down tube 20 is three-dimensionally bent, so that the longitudinal axis Q of the upper end portion that joins with the head pipe 21 is parallel to the axis Q2 of the head pipe 21. It is arranged so that. For this reason, both pipes 20.21
This makes it easier to expose the welded joint surface, making it easier to weld. Further, it is possible to perform reinforcement using a simple flat plate-shaped gusset 22, and it is also possible to use the gusset 22 to integrally reinforce the main pipe.

Furthermore, a down tube 2 as shown in FIGS. 7 and 8
If it is 0, the corner of the upper end of the down tube 20 does not protrude inward compared to the one shown in FIG. In this case, advantages such as an increase in the degree of freedom can be obtained.

"Effects of the Invention" As explained above, according to the present invention, square pipes are set on rolls and bent so that their outer surfaces are not perpendicular or parallel to the rotational axis of the roll mold. , a square pipe can be bent three-dimensionally so that each outer surface has the shape of a conical side surface, and the pipe as a whole can be bent three-dimensionally.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of a conventional motorcycle body frame, FIG. 2 is a perspective view of its down frame, FIG. 3 is a plan view of essential parts of a square pipe bending device according to the present invention, and FIG.
The figures are the ■ arrow view of Figure 3, Figure 5 (a), (+)), (c
) is a diagram showing a square pipe bent by the above-mentioned device, FIG. 6 is a perspective view of the same, FIG. 7 is a perspective view of an example in which the above-mentioned pipe is used in a body frame of a motorcycle, and FIG. FIG. 2 is a plan view of a portion of the motorcycle.

Claims (2)

[Claims] (1) A square pipe with a square cross section is extended in the tangential direction to the roll mold, a predetermined part of the square pipe is fixed to a predetermined position on the outer circumference of the roll mold, and the square pipe is rotated while the roll mold is rotated. In a square pipe bending method in which the square pipe is bent while being fed and rolled along the outer periphery of a roll mold, the square pipe is tilted so that each outer surface thereof is not perpendicular or parallel to the rotation axis of the roll mold. A method of bending a square pipe, which is characterized by bending the square pipe by setting it in a roll shape. (2) a roll mold that bends a square pipe with a square cross section while rolling it along the outer periphery as it rotates; a clamp mechanism that grips and fixes a predetermined portion of the square pipe on the outer periphery of the roll mold; When the square pipe is rotated to bend the square pipe, the pipe bending device is equipped with a pressure mold that presses the bending start part of the square pipe against the outer periphery of the roll mold against the bending reaction force. teeth,
A guide groove with a V-shaped cross section is provided, which contacts the two outer circumferential surfaces of the square pipe and bends the same square pipe in an inclined state so that the outer surfaces thereof are not perpendicular or parallel to the rotation axis of the roll type. The clamp mechanism is provided with a locking surface that abuts against the outer surface of the square pipe to hold and fix the same square pipe in the inclined state, and the pressure type is further provided with a locking surface that abuts on two outer surfaces of the square pipe. A square pipe bending device is provided with a pressure surface having a V-shaped cross section for pressing the same square pipe in the inclined state onto a roll mold.