JPS6366620B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is a method for forming a steel plate molded product having a cross section with key-shaped steps on the left and right hypotenuses of a trapezoidal mountain by cold roll forming. This is a roll forming method that is applied to forming deck plates, etc. used as synthetic floor boards for bridges, etc.

BACKGROUND OF THE INVENTION FIG. 2 shows a cross section of a certain deck plate used in composite flooring. This deck plate supports the poured fresh concrete during concrete pouring, and after the concrete hardens, it is integrated with the concrete to form a composite floor plate.

Conventionally, like this deck plate, trapezoidal mountain 1
As a method of forming a steel plate molded product having a cross section with hook-shaped step portions 3 as shown in an enlarged view in FIG. As shown in FIG. 5a, first, a rectangular base 4 is formed by bending the upper bending point E and the lower bending point F of the hook-shaped step 3 at right angles, and then, as shown in FIG. The bending points E and F of the hook-shaped step part 3 are bent by the upper and lower vertical bending rolls 5 and 6 placed in the middle of the roll forming stand, so that the lower bending point F is inside the upper bending point E. The rectangular base 4 is then tilted on its sides to obtain a predetermined final bent shape, and then, as shown in figure c, the upper and lower horizontal sections are bent so that the key-shaped step 3 is on the oblique side 2. There is one in which the trapezoidal peak 1 is formed using rolls.

[Problems to be Solved by the Invention] The above-mentioned key-shaped stepped portion 3 is a blind corner that goes inside and cannot be contacted by horizontal rolls, so it is impossible to form it using normal methods. Various methods are being devised, and the above-mentioned conventional molding method is one of them.

The above-mentioned forming method has no problem if the hook-shaped stepped portion 3 has a relatively gentle bending shape, but it becomes a problem if a sharp bending shape is required. That is, in FIG. 3, the depth dimension W and height dimension H of the key-shaped stepped portion 3 are small, the interval between the upper and lower bending points E and F is extremely narrow, and the bending angle (bending amount) α If is a large bent shape (and therefore has an acute angle as a bent shape),
There are the following problems. That is, (i) It is difficult to provide a sufficiently large rigidity to the support mechanism for the vertical rolls 5 and 6 as shown in FIG. It is difficult to ensure a predetermined bending R and inclination angle θ.

(ii) After forming the hook-shaped stepped portion 3, when forming the peak 1 as shown in Fig. 5c, as shown in Fig. 6,
During the process of forming from the previous roll to the next roll,
When the working pressure P is applied to the material to be formed, a tensile force T acts on the material to be formed, and the material returns to the hook-shaped stepped portion, causing deformation.

In other words, in FIG. 6, the dotted line shows the state of forming with the first roll, and the solid line shows the original shape to be formed with the next roll. However, due to the deviation of the bending intersection, the original unfolded length l of the oblique side 2 becomes (l - △ 1), and the inclination angle θ of the key-shaped stepped portion becomes large as shown by the two-dot chain line.

In order to correct the return deformation, even if re-forming is performed using a vertical roll disposed at a later stage, correction is extremely difficult because the absolute value of the developed length of the oblique side portion is insufficient. In addition, in the case of forming a deck plate as shown in FIG. also acts to further increase the return deformation.

For this reason, it has been extremely difficult to ensure the predetermined dimensions W, H, R, and θ of the shape of the key-shaped stepped portion 3.

The present invention was made against the above background, and an object of the present invention is to provide a roll forming method that can ensure a predetermined dimension even in the case of a sharply bent hook-shaped step.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides the first
By the following steps (i) to (iv) described with reference to the drawings, a cross section with hook-shaped steps on the left and right hypotenuses of the trapezoidal mountain was formed.

(i) The left and right key-shaped steps have bending points E and F at the same positions as the upper and lower bending points E and F of the key-shaped step 3, and the bending angle of the lower bending point F. is a right angle, and the bending angle of the upper bending point E is larger than the final bending angle. A step of forming a triangular protrusion 10 using upper and lower horizontal rolls 11 and 12, respectively (Fig. 1 a, b), (ii) left and right A step of pushing up the middle part 14 at the key-shaped step position with the lower horizontal roll 15 and tilting the right angle side of the triangular protrusion 10 so that the upper bending point E projects outward from the lower bending point F. (1st
Figures c) and (iii) With the left and right key-shaped stepped portions supported by the lower horizontal flat rolls 16, the intermediate portion 14 is
(Fig. 1 d), (iv) a step of rolling down the hook-shaped step portion 3 with the upper horizontal flat roll 17 to form a hook-shaped step portion 3 with a bending angle larger than a predetermined final bending point bending angle; 3, and then molding the trapezoidal peak 1 so that the key-shaped stepped portion 3 is on the oblique side (FIG. 1e).

[Operation] In step (i), the triangular protrusion 10 is formed not at a blind corner but by the upper and lower horizontal rolls 11 and 12, so that the upper bending point E can be formed into a sufficiently acute angle.

In step (ii), the intermediate portion 14 is rolled by the lower horizontal roll 1
When pushing up at step 5, the upper bending point E will move to the lower bending point F.
protrude more outward. This creates a blind corner.

In step (iii), since the bending angle at the bending point of the key-shaped stepped portion 3 is larger than the predetermined final bending point bending angle,
This solves the problem of insufficient developed length of the oblique side when forming the ridge, and since the ridge can be formed while anticipating return deformation in the previous roll, even if return deformation occurs in the next roll, the predetermined key can be maintained. It is possible to ensure the stepped shape.

[Example] The example described below is about molding a deck plate with the cross section shown in FIG.
It is molded by the molding steps shown in FIG. To roughly explain this forming process, () First, the central trapezoidal ridge 1 having the hook-shaped stepped portion 3 is formed in the steps shown in Fig. 4, and the dovetail portions 8 on both sides thereof are formed in the steps shown in Preliminary forming is carried out, the trapezoidal peak 1 on the edge side is roughly formed in the steps of () ~, the dovetail portion 8 is formed into a predetermined final shape in the steps of () ~, and the trapezoidal peak 1 on the edge side is formed in the steps of The trapezoidal peak 1 is also formed into a predetermined shape in parallel.

Note that the steps shown in the figure are forming stands with upper and lower horizontal rolls, and
The process shown in between is a forming process using vertical rolls arranged between horizontal roll stands. In addition, the illustrated steps ~ are shown with some of the molding stands omitted, and the actual number of molding stands is as follows.
Usually more.

Details will be explained below.

() process (~) The method of the present invention is employed in this step.

(i) The left and right key-shaped steps have bending points E and F at the same positions as the upper and lower bending points E and F of the key-shaped step 3, and the lower bending point F is bent. A triangular protrusion 10 whose angle is a right angle and whose bending angle at the upper bending point E is larger than its final bending angle α (that is, the bent shape is more acute) is formed by upper and lower horizontal rolls 11 and 12, respectively. (Figure 4 (~).

(ii) Push up the intermediate portions 14 at the left and right key-shaped stepped portions with the lower horizontal roll 15, and align the triangular protrusion 10 at right angles so that the upper bending point E extends outward from the lower bending point F. Slant the sides (Figure 4).

In this step of inclining the right angle sides of the triangular protrusion 10, the intermediate portion 14 is pushed up while restraining the outward escape in the width direction of the outer flat portions 13 at the left and right hook-shaped step positions, respectively; Flat part 1
There are two possible methods: a method of pushing up the intermediate portion 14 without constraining it in the width direction (that is, not rolling down the flat portion 13). In the former case,
Due to the reaction of the compressive force in the width direction of the material to be formed in the intermediate portion 14, the upper bending point E changes to the lower bending point F.
It will stick out more outward. In the latter case, the triangular protrusion 10 itself is tilted while the sharp bending shape of the apex (E) of the triangular protrusion 10 is maintained, so that the lower bending point F becomes the upper bending point E. It will go more inside.

(iii) With the left and right key-shaped stepped portions supported by the lower horizontal flat rolls 16, move the intermediate portion 14
is rolled down by the upper horizontal flat roll 17 to form a hook-shaped step at a bending point bending angle α' that is larger than the predetermined final bending point bending angle α (that is, at an angle that is more acute than the final shape as a bent shape). Part 3
(Figure 4).

In this case, in the step (ii) above, the lower bending point F
is slightly inside the upper bending point E, so
When rolled down with the upper horizontal flat roll 17, due to buckling deformation due to stress generated inside the material,
As described above, a sufficiently large bending angle α' (that is, an acute bending shape) can be obtained.

(iv) After forming the hook-shaped step 3, bend the trapezoid ridge 1 at the upper and lower bending point positions D and G using upper and lower horizontal rolls so that the trapezoid ridge 1 is bent so that the hook-shaped step 3 is on the oblique side. (Figure 4(,)).

In this case, the bending point D on the center side when forming the triangular protrusion 10 is bent in the opposite direction and becomes the upper bending point D of the trapezoidal peak 1. There is no problem in terms of appearance.

Steps () (Fig. 4~) While lifting the adjacent parts of the trapezoidal peak 1 with upper and lower horizontal rolls, bend the upper bending point M of the dovetail part 8 (Fig. 4), and then fold the dovetail part 8. By bending the lower bending point N of the isthmus, a rectangular protrusion 20 having bending points M and N at the same positions as the bending points M and N of the dovetail part 8 is placed in the center of the isthmus part 7. The bottom part of the side part 7 is molded in a lifted state so that it slopes upward (FIG. 4).

Step () (~) Next, the trapezoidal peak 1 on the edge side is roughly formed. This process is basically the same as the forming process (-) of the central trapezoidal peak 1 using the method of the present invention, although there are some differences therebetween. Although it is possible to form the trapezoidal peak 1 into the final shape in this step, it is preferable to form the trapezoidal peak 1 into the final shape in parallel with the subsequent steps in order to avoid increasing the number of roll forming steps.

In this step, the preliminarily formed shapes of the isthmus portion 7 and the dovetail portion 8 are maintained as they are.

Steps () (-) (i) First, the upper side 20a of the square protrusion 20 is formed into a downwardly convex arc shape using upper and lower horizontal rolls 21 and 22 (FIG. 4).

(ii) Next, the trapezoidal mountains 1, 1 on both sides of the isthmus part 7 position
While maintaining the interval at a predetermined final peak pitch P, the arcuate upper side 20a of the square protrusion 20 is pushed up by the lower support roll 23, and the left and right sides 20b of the square protrusion 20 are pushed up on the left and right sides. It is bent inward by the vertical rolls 24, 24, so that the lower bending point N of the rectangular projection 20 is placed inside the upper bending point M, and the side portion 20b is inclined. This process is performed between the upper and lower horizontal roll stands.

(iii) Next, while maintaining the same pitch P, the square protrusion 20 is pressed down by the upper and lower horizontal flat rolls 25 and 26 to return the bottom portion to the horizontal (Fig. 4~). In this horizontal return process, due to the buckling deformation due to the stress generated inside the material during the downward pressure reduction, the lower bending point N of the dovetail portion 8 goes sufficiently deeper inside than the upper bending point M, and a predetermined point is formed. A dovetail shaped part 8 is obtained.

In addition, this leveling process is as in the example,
This is usually done using a multi-stage horizontal roll stand.
As shown in the process between the horizontal roll stands, the vertical roll 27 and the support roll 2 are
8 so that the shape of the dovetail portion 8 smoothly transitions to the final bent shape.

In addition, in the embodiment, in the horizontal return step, the isthmus portion 7 is once pushed further down from the horizontal state (FIG. 4), and then returned to the horizontal state in the next stand (FIG. 4). This is to prevent spring back and obtain a correctly horizontal isthmus section 7.

In the embodiment, the cross section has a dovetail portion 8 in the isthmus portion 7 between the trapezoidal peaks 1.
The method of the present invention is not limited to this, and in short, the method of the present invention can be applied to any cross section having a hook-shaped step 3 on the oblique side 2 of the trapezoidal crest 1.

[Effects of the Invention] As explained above, according to the present invention, the following effects are achieved.

(i) The key-shaped step is formed using only upper and lower horizontal rolls with sufficient rigidity, without using vertical rolls with low rigidity, so the forming effect is high, and even if the shape is sharply bent, the specified Can be reliably molded into any shape.

(ii) The upper bending point of the hook-shaped step is formed in advance as the apex of the triangular protrusion, so it can be formed into a sufficiently sharp acute angle, and a hook-shaped step with a sharp bend can be formed. make it practical to do so.

(iii) Since the bending angle at the bending point of the pre-formed hook-shaped stepped portion is larger than the bending angle at the bending point of the final shape, the development length of the hypotenuse portion is insufficient when forming the trapezoidal mountain. This problem is significantly reduced, and since the trapezoidal peak can be formed with the previous roll taking into account the return deformation, it is possible to easily obtain a hook-shaped stepped portion of a predetermined shape.

Due to the above-mentioned high formability, even a hook-shaped stepped portion in which the two bending points of the sharply bent shape are close to each other at a narrow interval can be reliably formed into a predetermined shape and size.

(iv) Furthermore, since no vertical rolls as incidental equipment are required for forming the key-shaped stepped portion, the roll arrangement is simplified, and workability with respect to roll rearrangement, roll adjustment, etc. is improved.

[Brief explanation of drawings]

Fig. 1 is a molding process diagram explaining the method of the present invention, Fig. 2 is a sectional view of a deck plate that is the object of molding in an embodiment of the present invention, Fig. 3 is an enlarged view of part A in Fig. 2, and Fig. 4 Figures (Part 1), (Part 2), (Part 3),
(Part 4) is a molding process diagram showing an embodiment of the present invention for molding the deck plate shown in Figure 2, Figure 5 is a molding process diagram showing a conventional molding method, and Figure 6 is a problem with the conventional molding method. It is an explanatory diagram of points. DESCRIPTION OF SYMBOLS 1... Trapezoidal mountain, 2... Oblique side part, 3... Key-shaped stepped part, 10... Triangular protrusion, 11, 12... Upper and lower horizontal rolls, 13... Flat part, 14... Intermediate part, 1
5... lower horizontal roll, 16... lower horizontal flat roll, E... upper bending point, F... lower bending point,
α...Bending angle at bending point.

Claims (1)

[Scope of Claims] 1. A method of forming a steel sheet molded product having a cross section with hook-shaped steps on the left and right hypotenuses of a trapezoidal mountain by cold roll forming, comprising: (i) at the positions of the left and right hook-shaped steps; , a triangular shape that has a bending point at the same position as the upper and lower bending points of the hook-shaped step, the bending angle of the lower bending point is a right angle, and the bending angle of the upper bending point is larger than the final bending angle. forming the protrusions using upper and lower horizontal rolls; (ii) pushing up the intermediate portions of the left and right key-shaped steps with lower horizontal rolls so that the upper bending point protrudes outward from the lower bending point; (iii) While the right and left hook-shaped steps are supported by the lower horizontal flat rolls, the middle part is rolled down by the upper horizontal flat rolls to form a predetermined shape. forming a hook-shaped step with a bending angle larger than the final bending point bending angle; (iv) forming a trapezoidal crest so that the hook-shaped step is on the oblique side after forming the hook-shaped step; A method of roll forming a cross section having a hook-shaped step on the hypotenuse of a trapezoidal mountain, which comprises the following steps: