JPS6015026A - Joining end of square pipe and its forming method - Google Patents

Abstract

PURPOSE:To form a joining end of a square pipe excellent in strength easily and efficiently by pressing the square pipe between a mandrel and a die and tapering top and bottom and forming a side to bulged form having a flange face at the tip. CONSTITUTION:A mandrel 61 having tapered faces 62a at the top and bottom and provided with the tip part 62 having lacked left and right sides is fitted into a square pipe 3. A die 71 in which a forming chamber 74 consisting of upper and lower formed faces 73 and formed faces 75 that extend to left and right outside is shifted by a lift cam 72 to press the tip of the square pipe 3. By this way, a joining end 3a having upper and lower faces 11, 12 of tapered off faces 13, 14, left and right sides 15, 16 of widened tapered faces 17, 18, a flange part consisting of a bent part 23, a bulged part 22, excellent in strength, rigidity and appearance, high in dimensional accuracy and having joining part 25 of sufficient welding area can be formed easily by one process.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a joining end of a square pipe and a method of forming the same when welding a pipe material or a shaft member to the end.

Conventionally, forming the joining end of this type of square pipe & 1. First, slits were cut on the left and right sides of the end of the square pipe, and then the slit was closed. The pipe is formed into a tapered shape, the slits are welded together, and the top and bottom are joined together, and then the joint is made by cutting out semicircular grooves (for example, semicircular grooves that correspond to the pipe surface) on the left and right sides of the tip of the square pipe. .

For this reason, conventional joining ends of square pipes have grooves cut out on the left and right sides, which is not the best in terms of strength and rigidity, and it is difficult to secure a sufficient welding area with the pipe for joining. (For example, when welding the rear fork pipe material of a motorcycle and a rectangular fork pipe, especially in large vehicles, there is a disadvantage that small items such as reinforcing patches must be used due to the lack of strength.)

In addition, the conventional forming method requires cumbersome processes such as cutting slits on the left and right sides of the end of the square pipe, and crushing and welding the slits, resulting in poor workability and productivity, and is also disadvantageous in terms of cost. It is.

The present invention has been devised to solve the above-mentioned problems, and the object of the present invention is to provide an end for joining square pipes that is superior in strength and rigidity and can secure a sufficient welding area. The object of the present invention is to provide a molding method for the same with excellent workability and productivity.

In order to achieve the above-mentioned object, the present invention has a first aspect of the present invention, which includes upper and lower surfaces that approach as they reach the tip, left and right side surfaces that separate as they reach the tip, and flange surfaces that bend the left and right side tips outward. The second invention is characterized in that a joint part corresponding to the joint part is formed between the top and bottom ends of the upper and lower surfaces and the flange surface, and the second invention is a molding method thereof, so that it is suitable for a tapered mandrel having an internal square pipe end part. Pressure is applied to form the end into a tapered tapered shape with the top and bottom collapsed, the side surface of the end bulges outward, and the bulge end is further bent outward to form a flange surface. It is characterized by what it did.

The present applicant has already filed a method for forming the end of a square pipe in Japanese Patent Application No. 57-228526, and the second invention relates to an improvement of this earlier application.

Hereinafter, a case will be described in which a preferred embodiment of the present invention is applied to a rear fork of a motorcycle.

FIG. 1 shows a plan view of the rear fork 1, and the rear fork 1 includes a pipe material 2 and a pair of left and right square pipes 3.3 whose joining ends 3d are welded to the pipe material 2' and extend rearward. .

The joining end portion 3a of the square pipe 3 has a shape before welding as shown in a side view in FIG. 5, a plan view in FIG. 6, and a top view in FIG. The piece 11 and the lower piece 12 are formed into tapered surfaces 13 and 14 that gradually approach each other as they reach the tip, and the left and right widths gradually become dog-like as they reach the tip, and corresponding to the tapered surfaces 13 and 14, left and right side pieces 15, 16 is formed into tapered surfaces 17 and 18 which are gradually spaced apart from each other as they reach the tip and whose height is gradually reduced as they reach the tip.

Further, the left and right ends of the tips 21° 21 of the upper and lower tapered surfaces 13.14 are respectively bulged outward to the left and right 22.22L, the tips of the left and right tapered surfaces 17.18 are bent outward 23, 23L,
・Flange portions 24.24 shaped to be joined to the pie 2° material 2 are formed on the left and right by the bulging portion 22.22 and the bent portion 23.231'', and the tips 21 of the upper and lower tapered surfaces 13, 14 are clearly formed.
．． 21 is formed into a shape to be joined to the pipe 2, and the flange portion 24.24 and the tapered surface tip 2L 21 constitute a joint portion 25.

The flange portion 24 of the joining end portion 3a and the tips 21.21 of the upper and lower tapered surfaces 13.14 are welded to the pipe material 2, square pipes 3°3 are attached to both sides of the pipe material 2, and the square pipes 3, 3 are attached. A cross plate 26 is horizontally joined between the intermediate portions of the square pipes 3, and an end piece 27 is welded to the rear end of each square pipe 3 to obtain the rear fork 1.

Therefore, according to the joining end portion 3a of the square pipe 3 according to the present invention, the left and right side pieces 15 and 16 are gradually wavy, and their tips are formed into outwardly bent flange portions 24. Since the joint portion has a larger joint span than its dimensions, the strength of the joint with the pipe material 2 can be increased.

In addition, since there are flange parts 24 and 24 on the left and right sides of the tip, the joint area is large and the joint strength can be further increased.
This is particularly advantageous when brazing and welding. Furthermore, since there are no notches or welds on the side surface of the tip as in the conventional case, the strength and rigidity are high, and the appearance can be improved.

8 shows a side view, and FIG. 9 shows a second embodiment of the present invention.

In the second embodiment, the left and right sides 32, 33 of the square pipe end 31
The tips are each bent outward to form flange surfaces 34 and 34 to ensure a bonding area.

FIG. 10 is a plan view of the bonded state, and FIG. 11 is a side view of the same, showing a third embodiment of the present invention.

In the third embodiment, the joint 36 includes the flange surface 35.35.
is formed into a substantially U-shape when viewed from the side, corresponding to the shape of the pipe material 2a.

Next, a method for forming the joining end portion 3a of the square pipe 3 will be explained in relation to a forming apparatus.

Fig. 2 shows a cross-sectional side view of the main part of the molding device, and Fig. 4 shows a plan view of the same. The base 53 has rotation 1
1Q1154 is installed vertically, and a handle 5 is attached to the upper end of the rotating shaft 54.
Install 5.

The base 53 has a proximal end 61a connected to the rotating shaft 54 and has a mandrel 61 projecting thereon, and a gap is formed in the current surface 52 so that the mandrel 61 can horizontally rotate at a required angle.

The base portion 61b of the mandrel 61 is formed to fit closely with the inner surface of the square pipe 3, and the intermediate portion 61c is formed to have a small diameter so as to fit loosely with the square pipe 3. The tip 62 of the mandrel 61 is formed so that the base 62a is tightly fitted into the square pipe 3, and the lower surface thereof has tapered surfaces 62b, 62b corresponding to the tapered surfaces 13 and 14. Form and tip 62
A fitting portion 62d is formed on the tip side by cutting out the left and right side portions closer to c.

The length from the above-mentioned surface 52 to the tip 62c of the mandrel 61 is formed to be approximately equal to the length of the square pipe 3 that is the workpiece.

A guide 71 is provided on the base 51 so as to face the tip 62 of the mandrel 61, and the dia 1 is formed to be movable along the longitudinal direction of the mandrel 61 by a lift cam 72 that moves up and down with a ram or the like. .

A molding chamber 74 is defined in the diamond 1 by upper and lower molding surfaces 73 and 73 corresponding to the tapered surfaces 13 and 14, and from the deep part of the molding chamber 74, the left and right tapered surfaces 17,
18, molding surfaces 75 corresponding to the flange portions 24 and 24, respectively;
A forming part 76.76 is provided protrudingly, and an image forming part 76.7 is provided.
A fitting hole 77 that can be freely fitted to the fitting portion 62d is formed between the holes 6 and 6.

In the above process, first, the handle 55 is rotated to horizontally turn the mandrel 61 as shown in FIG. 4, and the square pipe 3 is fitted into the mandrel 61 from the tip 62.

Next, the handle 55 is returned to align the axis of the mandrel 61 with the center of the diamond 1, and the square pipe 3 is further pushed in to bring the rear end 3b of the square pipe into contact with the surface 52 for the time being.

Next, by the downward movement of the cam 72, the bottom ear 1 is moved to the mandrel 6.
Move it to the 1st side.

By moving the diamond 1, the tip of the square pipe 3 first enters the molding chamber 4, and pressurizes the two pieces 11 and the lower piece 12 while sliding and moving on the two lower molding surfaces 73, 73, and the square pipe Squeeze the tip of 3 up and down to bulge outward to the left and right.

Eventually, as the diamond 1 moves, the fitting portion 62d will fit into the fitting hole 7.
7, and at the same time, the left and right molded parts 76 and 76 enter the distal end of the rectangular vibrator 3 which has been bulged and deformed.

The penetration of the molded portions 76 and 76 pushes the left and right side pieces 15°16 outward, respectively, and bends the tips outward to form the above-mentioned -
The bottom molding surface 73.73, the left and right molding parts 76.76,!
The tapered surfaces 62 ′b and ’62b of the metal plate 61 form the joining end portion 3a having the joining portion 25.

After molding, the lift cam 72 is moved upward, and the diamond 1 is moved backward by appropriate means to release the engagement between the diamond 1 and the square pipe 3.

Next, the rotating shaft 54 is rotated by the handle 55, and as a result, the square pipe rear end 3b moves to the side while following and abutting the surface 52, and moves in the direction of detaching from the mandrel 61, and then moves it to the side. This is shown in phantom lines in Figure 4.

Therefore, according to the present invention, the joining end 3a of the square pipe 3 can be easily tapered without requiring the conventional notching process and welding process, and the tapering can be performed by crushing the square pipe 3 vertically. At the same time, left and right side pieces 15.1
6 can be easily bulged outward.

In addition, since the flange portion 24 is formed using the portion that is pressed up and down and bulges outward, there is no waste of material and the flange portion 24 can be easily formed. Since it is made of solid wood, the molded joining end portion 3a has excellent strength, rigidity, and appearance, and since it is press-formed using the core metal 61 and the diamond 1, it is possible to mold the joint portion 25 with high dimensional accuracy.

As is clear from the above explanation, according to the joining end portion of a square pipe according to the present invention, a joining area can be secured, joint strength, rigidity, appearance, etc. can be improved, and the molding according to the invention According to the method, a number of excellent effects such as the ability to efficiently and easily form the joining end portion are exhibited.

[Brief explanation of drawings]

Fig. 1 is a plan view of the rear fork, Fig. 2 is a cross-sectional side view of the main part of the forming device, Fig. 3 is a plan view of the forming section, Fig. 4 is a plan view of the forming device, and Fig. 5 is the square pipe. 6 is a side view of the joining end of 1. FIG. 6 is a plan view of the same. 7 is a view taken along the Vll arrow in FIG. 5, FIG. 8 is a side view of the second embodiment, and FIG. 9 is a
10 is a plan view showing the joined state of the third embodiment, and FIG. 11 is a side view of the same. In addition, 3 in the drawing is a square pipe, 3a is a joining end, 13.14
．． 17 and 18 are tapered surfaces, 24 is a flange portion, 61 is a mandrel, and 71 is a gouer. Patent applicant Honda Motor Co., Ltd. agent Patent attorney 2 1) Production department Patent attorney Kuni Ohashi Production volume Patent attorney Yu Koyama

Claims (2)

[Claims] (1) Approaching toward the tip (comprising upper and lower surfaces, left and right side surfaces that become separated as they reach the tip, and flange surfaces formed by bending the tips of the left and right side surfaces outward, and joined at the tips of the upper and lower surfaces and the flange surfaces) The joint end of a corner) where a joint corresponding to the location is formed. (2) Pressure is applied to fit the tapered tenno (shaped core metal) with the square pipe end inside, and the end is formed into a tapered shape with the top and bottom crushed, and the @11 surface of the end is directed outward. A method of forming a joining end of a square pipe by bulging and further bending the bulging end outward to form a flange surface.