JPS6366619B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a method of forming a steel sheet molded product having a cross section with a dovetail portion in the isthmus between the mountains by cold roll forming, For example, this is a roll forming method applied to forming deck plates used as synthetic floor boards for buildings, 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, there is a method of forming a steel plate molded product having a cross-section with a dovetail-like part 3 in the isthmus part 2 between the peaks 1 and the bent part is shown in an enlarged view in Fig. 3. There is a molding method shown in the molding process diagrams shown in FIGS. 5a to 5f. That is, first, the mountain 1 is formed (a in the figure). This mountain 1 is the central mountain, and FIGS. 5 a to 5 f show the right half from the center, and the molding is performed symmetrically.

Next, as shown in FIG. A rectangular protrusion 4 having a curved point is formed in a raised state so that the bottom part 2a of the isthmus part 2 is inclined upward. A portion of this cross-sectional shape (a portion of the isthmus portion 2) in which the square protrusion 4 is located at the center of the bottom portion 2a in the lifted state is tentatively referred to as a lifting protrusion 5.

Next, the outer peak 1 is formed (c in the same figure).

After completing the forming of the cross section with the lifting protrusion 5 between the two peaks 1, 1 of the predetermined final peak pitch P as described above, the thrust bending force by the vertical thrust rolls and the horizontal bottom part by the upper and lower horizontal rolls are applied. A dovetail is formed by the forces acting within the material during return. In other words, between the upper and lower horizontal roll stands,
As shown in e and f, the upper left and right vertical bending rolls 6, 6 and only one of the lower vertical bending rolls 7 bend the lower bending point N into a square shape. The side part 4b of the protrusion 4 is inclined, and the lifting protrusion 5 is successively pushed down between the upper and lower horizontal rolls. In this case, there is no space to arrange two lower vertical bending rolls 7, so
They are arranged alternately as shown in d, e, and f in the figure.

Note that the forming process diagram in FIG. 5 shows only the main forming rolls, and in reality, the forming process is performed using multiple stages of forming rolls.

[Problems to be Solved by the Invention] The above dovetail portion 3 has a blind corner where the lower bending point N goes inside the upper bending point M and cannot come into contact with the horizontal roll. Because of this, it is impossible to mold 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 bent portion of the dovetail 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 bent portion of the dovetail portion 3 are small, the interval between the upper and lower bending points M and N is extremely narrow, and the bending radius R is small. , and in the case of a bent shape in which the bending angle α is considerably larger than 90°, the following problems occur. That is, (i) It is difficult to provide a sufficiently large rigidity to the support mechanism of the vertical rolls 6, 7 as shown in Figures 5d, e, and f. It is difficult to ensure a predetermined small bending radius R and a large bending angle α in the bent portion of the portion 3.

(ii) The lower vertical bending roll 7 can only be placed on one side of the bent portion of the dovetail portion 3 due to the narrow space. Since the molding is performed alternately, the unbalance of the acting force causes return deformation in which the inclination angle θ increases, making it impossible to mold into the desired shape.

(iii) If the ridges are high or the ridges are close to the dovetail portion 3 in the cross section, the upper vertical bending roll 6 will hit the ridges, making forming impossible, as shown in FIG.

For this reason, it has been extremely difficult to ensure the predetermined dimensions W, H, R, and θ in the bent portion of the dovetail 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 if the dovetail portion has a sharply bent shape.

[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 a dovetail-like part was formed in the isthmus between the mountains.

(i) A circle with mountains formed on both sides of the isthmus position, a bending point at the same position as the dovetail bending point in the center of the isthmus position, and whose upper side is convex downward. (ii) forming an arcuate square protrusion by pulling it down so that the bottom part of the isthmus slopes downward; (ii) while maintaining the interval between the peaks on both sides of the isthmus at a predetermined final peak pitch P; , the step of pushing up the arcuate upper side of the rectangular protrusion with a lower support roll, and pushing up and lowering the lowered isthmus part with upper and lower flat rolls to return the bottom part to horizontal.

In FIG. 1, T indicates an upper horizontal roll, and B indicates a lower horizontal roll.

[Operation] If the upper side 4a of the square protrusion 4 is formed into a downwardly convex arc shape, the bending angle α of the upper bending point M will be 90° or more. Moreover, since this bending is performed by upper and lower horizontal rolls that can apply a sufficiently strong rolling force, a sufficiently small bending radius R can be obtained. That is, a small bending radius R and a bending angle of 90° or more are achieved at the upper bending point M position before forming the blind corner, which facilitates forming in the subsequent process.

When the bottom part 2a is pulled down so as to be inclined downward, the bending angle α of the lower bending point N becomes 90° or more. Moreover, since this bending is performed using upper and lower horizontal rolls, a sufficiently small bending radius R can be obtained. In other words, before making it a blind corner,
A small bending radius R and a bending angle of 90° or more at the lower bending point N position are achieved, which facilitates shaping in subsequent steps.

Since the support rolls 17 act symmetrically on the dovetail portion, there is no unbalance of the acting force as in the conventional case where a vertical roll is applied only to one side of the bent portion, and there is no return deformation that increases the inclination angle θ. Can be molded.

When the mountain pitch P is fixed and the isthmus part is pushed up and down by the upper and lower flat rolls 19, 20, the bending angle of the lower bending point M and the bending angle of the lower bending point N are already larger than 90°. Because it is sharpened, buckling deformation occurs due to the acting force within the material even without using vertical rolls, and the lower bending point N of the dovetail portion 3 changes to the upper bending point M. It goes further inside and is formed into a predetermined dovetail shape.

[Example] The example described below concerns the molding of a deck plate having the cross section shown in FIG.
That is, it has three trapezoidal peaks 1, a hook-shaped step 7 on the oblique side 6 of each trapezoidal peak 1, and a dovetail-shaped part in the center of the isthmus 2 between the trapezoidal peaks 1. It is a cross section with 3. This deck plate is molded by the molding process shown in FIG. To roughly explain this forming process, () First, the central trapezoidal peak 1 having the key-shaped stepped portion 7 is formed in the steps shown in FIG. Form a square protrusion 4 in the center of the position where it should become 2), () In the process shown in Figure 4~, trapezoid ridge 1 on the edge side
The square protrusion 4 is formed into a dovetail portion 3 having a predetermined shape in the steps shown in FIG.

Note that the illustrated steps are shown with some of the molding stands omitted, and the actual number of molding stands is usually much larger. Further, T in the figure indicates an upper horizontal roll, and B indicates a lower horizontal roll.

Details will be explained below.

() process (~) This process consists of the central trapezoidal peak 1 with the key-shaped step 7.
This is the process of molding.

(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 7, and the lower bending point F is bent. A triangular protrusion 8 having a right angle and a bending angle at the upper bending point E larger than the final bending angle is formed by upper and lower horizontal rolls 9 and 10, respectively (FIG. 4(-)).

(ii) Push up the intermediate portions 11 at the left and right key-shaped stepped portions with the lower horizontal roll 12, and align the triangular protrusion 8 at right angles so that the upper bending point E extends outward from the lower bending point F. Slant the sides (Figure 4).

(iii) With the left and right key-shaped stepped portions supported by the lower horizontal flat rolls 13, move the intermediate portion 11
is rolled down by the upper horizontal flat roll 14 to form a hook-shaped step 7 with a bending angle larger than a predetermined final bending angle (FIG. 4).

(iv) After forming the hook-shaped step 7, 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 7 is on the oblique side. (Figure 4(,)).

In this case, the bending point D on the center side when forming the triangular protrusion 8 is reversed in the direction of bending and becomes the upper bending point D of the trapezoidal peak 1. There is no problem in terms of appearance.

Step () (Fig. 4~) Form a square protrusion 4 in the center of the isthmus 2 position with bending points M and N at the same positions as the bending points M and N of the dovetail portion 3. .

Step () (Fig. 4A~) Next, the trapezoidal peak 1 on the edge side is formed. This process is the forming process of the central trapezoidal peak 1 (Fig. 4~
) There are some differences, but they are basically the same. The trapezoidal peak 1 may not be formed into the final shape in this step, but may be formed into the final shape in parallel with the subsequent steps. Note that in this step, the shape of the square protrusion 4 is maintained as it is.

Step () (Fig. 4~) This step is a step of forming the square protrusion 4 into a dovetail-shaped portion.

(i) The upper and lower horizontal roll stands 15 and 16 form the upper side 4a of the rectangular protrusion 4 into a downwardly convex arc shape, and the lower side 2a of the isthmus 2 is pulled down so that it slopes downward. figure). A portion of this cross-sectional shape (the portion of the isthmus portion 2) having the rectangular protrusion 4 at the center of the bottom portion 2a in the pulled-down state is tentatively referred to as a pull-down protrusion 5. At this stage, the interval between the peaks is set to a predetermined final peak pitch P.

The process of forming into the shape shown in FIG. 4 is not limited to that of the embodiment. For example, a method may be employed in which forming the bottom side 2a to be inclined, forming the square protrusion 4, and forming the upper side 4a into an arc shape are carried out in parallel. In addition, in general, in roll forming of wide material, the center part is formed first and the edge sides are formed sequentially.
The order is the square protrusion 4 next to it, and the trapezoidal peak 1 on the edge side. For example, if the dovetail part 3 is a cross section in the center of the material, the square protrusion 4 is first, then the trapezoid ridge 1 on the edge side.
The trapezoidal peaks 1 on both sides thereof will be formed. Further, instead of completing the shapes of the trapezoidal peak 1, the square protrusion 4, and the trapezoidal peak 1 individually, they may be formed in parallel and completed at the same time.

(ii) Next, set the interval between peaks 1 to a predetermined final peak pitch P.
while keeping the arcuate upper side 4a of the square protrusion 4 pushed up by the lower support roll 17, and the isthmus part 2 in the lowered state;
That is, the above-mentioned lowering protrusion 5 is pushed up and down by the upper and lower flat rolls 19, 20 to return the bottom portion 2a to the horizontal position (FIG. 4). In this bottom horizontal return process, since the peak pitch P is fixed, the buckling deformation due to the stress generated inside the material during up-pressing causes the lower bending point N of the dovetail portion 3 to change to the upper bending point. Curved point M
It penetrates deeper inside and forms a dovetail shape. Then, in the final process, further shaping is performed (Figure 4).

Although the embodiment has a hook-shaped stepped portion 7 on the oblique side of the mountain, it is of course applicable to a simple mountain without the hook-shaped stepped portion 7. Also,
Of course, it can be applied not only when the peak is located at the center in the width direction of the material, but also when the dovetail portion is located at the center.

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

(i) Since the upper side 4a of the square protrusion 4 is formed into a downwardly convex arc shape by upper and lower horizontal rolls, a small bending radius R and 90° are formed at the upper bending point M position before forming the blind corner. A bending angle of more than 100° can be achieved, facilitating shaping in subsequent steps.

(ii) Since the bottom part 2a is lowered so as to be tilted downward by the vertical horizontal rolls, a small bending radius R and a bending angle of 90° or more are required at the lower bending point N position before forming a blind corner. is achieved and facilitates molding in subsequent steps.

(iii) Since the support rolls 17 act symmetrically on the dovetail portion, there is no unbalance in the acting force that occurs when a vertical roll is applied to only one side of the bending portion, as in the conventional case, and the return angle θ increases. Molding without deformation is possible.

(iv) Since no vertical roll is used, there is no problem such as the vertical roll hitting a mountain and making it impossible to form.

As mentioned above, the conventional problems have been solved, and even if the dovetail part has a small depth dimension W and height dimension H of the bent part of the dovetail part and has a sharp bending shape,
It becomes possible to reliably mold the product to a predetermined shape and size.

(iv) Furthermore, since no vertical rolls as incidental equipment are required for forming the dovetail portion, the roll arrangement is simplified and the 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 Diagrams (Part 1), (Part 2), (Part 3)
2 is a molding process diagram showing an embodiment of the present invention for molding the deck plate, FIG. 5 is a molding process diagram showing a conventional molding method, and FIG. 6 is an explanatory diagram of problems in the conventional molding method. It is. 1...Mountain (trapezoidal mountain), 2...Isthmus, 2a...
Base portion, 3... Dovetail portion, 4... Square protrusion, 4
a...Top side, 4b...Side part, 5...Pulling down protrusion, 17...Support roll, 18...Vertical bending roll, 19, 20...Vertical horizontal flat roll, M...Top bending point , N...lower bending point, P...
...Yamapitsuchi.

Claims (1)

[Scope of Claims] 1. A method of forming a steel plate molded product having a cross-section with a dovetail-shaped part in the isthmus between the mountains by cold roll forming, comprising: (i) both sides of the isthmus; At the same time, in the center of the isthmus part, a rectangular protrusion having a bending point at the same position as the bending point of the dovetail part and an arc shape with the upper side convex downward is formed. (ii) Forming in a pulled down state so that the bottom part of the side part slopes downward; (ii) While maintaining the interval between the peaks on both sides of the isthmus position at a predetermined final peak pitch P, shaping the square protrusion into an arc shape; The isthmus part is characterized by the step of pushing up the upper side of the lower part by a lower support roll, pushing up and lowering the lowered part of the isthmus part by upper and lower flat rolls, and returning the bottom part to the horizontal level. A method of roll forming a cross section with a dovetail.