JPH04200932A - Method for forming flange - Google Patents

Abstract

PURPOSE:To remove camber and to improve accuracy of dimension and shape by holding a flange between a pair of dies in the final forming stage of flanges and elongating edge side parts more in the direction along the curve. CONSTITUTION:A tertiary formed body 116 having a preliminary bent part 114 wherein end parts in the lengthwise direction of a pair of side walls 104 are bent outward is set in a groove 86 of a fourth forming apparatus 26. A punch part 94 is inserted by the fall of a punch 84 into the tertiary formed body 116 to hold side walls 104 between the side wall surfaces of the groove 86. With the fall of the punch part 94 the pressure surface 96 engages with the edges of the preliminary bent parts 114 and the edges of inclination receiving surfaces 90 are bent to form the flanges 16. In this way, a pair of side walls 14 extend from the bottom wall 12, the flanges 16 extending outward are formed in each end part parallel to the lengthwise direction of the side walls 14 and a product 10 wherein the entire body is curved in a concaved form to the projecting end sides can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a flange forming method, in particular,
The present invention relates to a method for forming a stretch flange in which the edge size is longer after forming than before forming.

Conventional technology A stretch flange is formed by bending the end of a plate-shaped material along a concave curve inside the edge and toward the edge. When bending material along such a curve,
If the edge of the flange is not extended to a length that is longer than before forming and corresponds to the length of the bending curve, tensile stress will remain in the flange and warp will occur. Therefore, in the flange forming apparatus described in Japanese Utility Model Application Publication No. 58-93322, after forming a waveform with a high edge on the part of the material that will become the flange, the waveform is formed while bending the flange forming part along the curve. It is stretched flat to form a flange. In this way, the material is stretched in advance by forming the waveform, and no tensile stress is generated in the flange forming part, so that a flange without warp can be formed.

SUMMARY OF THE INVENTION This flange forming apparatus is designed to form a flange using a pair of molds that move relatively in a direction parallel to the plate surface of the flange to be finally formed. Molding may also be performed using a pair of molds that move relative to each other in a direction that intersects the surface.

In this case, like the flange forming apparatus in the above publication, first a corrugation is formed on the end of the material, and then the flange is formed by extending the corrugation while bending the end of the material, thereby creating a flange without warping. If it can be molded, it requires two steps: a wave forming process and a flange forming process. When forming a flange by relatively moving a pair of dies in a direction parallel to the plate surface of the flange, the ends of the material extend in a direction that intersects the direction of relative movement of the pair of dies, and the dies are During the relative movement, the end of the material is first pinched from both sides to form a waveform, and then the end of the material is further moved relative to each other to form a flange. It can be done in one step.

On the other hand, if a pair of molds moves relative to each other in a direction that intersects the plate surface of the flange, the end of the material will be located parallel to the direction of movement of the molds, so this mold will not move. Sometimes it is possible to form a corrugated shape by sandwiching the ends of the material from both sides, but it is necessary to form the corrugated shape in advance using a separate mold, and two steps are required to form the flange, resulting in high molding costs. turn into.

The present invention provides a forming method that can form a stretch flange without warping by using a pair of molds that move relative to each other in a direction intersecting the plate surface of the flange, without forming a waveform on the end of the material in advance. This was done with this in mind.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention bends the end of a plate-like material along a concave curve inside the end edge and toward the end edge to form a flange. In this method, a flange is formed by a pair of molds that move relatively in a direction intersecting the plate surface of the flange, and in the final stage of the flange forming, the flange is sandwiched from both the front and back sides by the pair of molds, and the flange is molded along the above-mentioned curve. In the direction shown in FIG.

Actions and Effects of the Invention When forming a flange by bending the end of a material along a concave curve inside the edge and toward the edge, a larger tensile stress is generated toward the edge of the flange. but,
In the final stage of flange forming, if the end edge side is stretched more, it is possible to form a flange with dimensions that correspond to the end edge dimensions or the bending curve without leaving any stress, resulting in a flange that does not warp and has high dimensional and shape accuracy. can be obtained.

Furthermore, since the flange is molded by being tightly sandwiched between the front and back sides by a pair of molds, wrinkles do not occur.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In this example, the product 10 shown in FIGS. 15 and 16 is molded. This product IO has a pair of side walls 14 extending from the bottom wall I2, and a flange 16 extending outward is formed at each end parallel to the longitudinal direction of the side walls I4. It has a concavely curved shape on the protruding end side. This product 10 has a material 20 shown in FIG. 7 in first, second, third and fourth molding devices 2 shown in FIGS. 6, 4, 3 and 2 respectively], 22. 2/I, 26 are sequentially molded. Each device will be explained below.

The first molding device 21 shown in FIG. 6 includes a die 30 provided in a fixed position and a punch 32 provided so as to be movable up and down. The die 30 has a groove 34 which is open in its upper surface and has a rectangular cross-section, and the punch 32 has a rectangular cross-section corresponding to the groove 34.

The second molding device 22 shown in FIG. 4 has a lower mold 40 which is provided in a fixed position, and a second mold 42 which is provided so as to be movable up and down. A mold member 44 on which a material is placed is fixed to the center of the lower mold 7io. The upper surface of this mold member 44
As shown in the figure, it is a curved concave surface 46 that is convexly curved downward in the longitudinal direction. A movable cam 48 is also provided on the lower mold 40 so as to be movable horizontally and in a direction orthogonal to the longitudinal direction of the mold member 44. On the side of the movable cam 48 facing the mold member 44, there is a pressure adjusting member 5 made of an elastic body such as urethane rubber, a spring, or a gas cylinder.
A wrinkle suppressing member 52 is also attached via 0.

On the other hand, the upper die 42 is provided with a punch 56. As shown in FIG. 5, the punch 56 is made to protrude downward from the center in the longitudinal direction, and has a curved tip surface. The upper mold 42 is also provided with a fixed cam 60,
As the upper mold 42 descends, the movable cam 48 is moved toward the mold member 44 side.

As shown in FIG. 3, the third molding device 24 includes a lower mold 64 provided in a fixed position and a lower mold 64 provided movably up and down.
It has two types 66 that can be moved toward and away from each other.

A groove 68 having a rectangular cross section is formed in the lower die 64. The bottom surface of the groove 68 is connected to the mold member 44 of the second molding device 22.
Similarly to the curved concave surface 46 of , the longitudinal direction (direction perpendicular to the paper surface)
The curved concave surface 70 is convex downward. Also,
A pair of open end portions parallel to the longitudinal direction of the groove 68 are each formed with an inclined receiving surface 72 that is inclined outward toward the upper side. This inclined receiver 72 is also curved convexly downward in the longitudinal direction. On the other hand, in the upper mold 66, a punch 76 is attached to a mold plate 77 via an elastic body 74. The tip surface of the punch 76 is a curved convex surface corresponding to the groove 68, and bending blades 78 are fixed to the upper die 66 at positions on both sides of the punch 76, respectively. Each of these bending blades 78 is formed with an inclined bending surface 80 corresponding to the inclined receiving surface 72, and this inclined bending surface 80 is curved convexly downward in the longitudinal direction.

As shown in FIG. 2, the fourth molding device 26 includes a die 82 provided in a fixed position and a punch 84 provided so as to be movable up and down. The die 82 has an opening on its top surface,
A groove 86 with a rectangular cross section is formed, the bottom surface of which is a curved concave surface 88.

Further, the upper surface of the die 82 has an inclined support 90 which is inclined upwardly toward the outside as shown in FIG. Even if the upper surface of the die 82 is flat, when the end of the material is bent to form a flange, the edge side is extended a lot and the thickness becomes thinner, and the plate surface of the flange is tilted at an angle α. However, in the inclined receiver, the inclination angle of the surface 90 is set to β which is larger than α. Further, the surface 90 of the inclined receiver is curved convexly downward in the longitudinal direction. On the other hand, punch 8
4 is provided with a punch portion 94 extending downward, and pressing surfaces 96 are formed on both sides of the punch portion 94, which are either horizontal in the width direction or convex downward in the longitudinal direction. .

Next, molding will be explained. First, the material 20 shown in FIGS. 7 and 8 is molded by the first molding device 21. This material 20 is a flat plate made of high tensile strength steel. The raw material 20 is bent by the first forming device 21 along a pair of straight lines extending in the longitudinal direction to form the primary molded product 100 shown in FIGS. 9 and 10. - The next molded product 100 has a groove shape with a pair of side walls 104 extending from the bottom wall 102.

Next, the next molded product 00 is molded by the second molding device 22. - When the next molded product 100 is placed on the mold member 44, the bottom wall 10 of the primary molded product 100 as shown in FIG.
There is a gap between 2 and the curved concave surface 46 of the mold member 44,
As the upper die 42 descends, the fixed cam 60 engages with the movable cam 48, and by moving it toward the die member 44, the wrinkle suppressing member 52 comes into contact with the side wall 104. At this time, the tip end surface of the punch 56 has not yet come into contact with the bottom wall 102, and no force is applied to the next molded product 100. When the upper mold 42 is further lowered from this state, the tip end surface of the punch 56 contacts the bottom wall 102 and bending starts, but at the same time, the movable cam 48 is pushed by the fixed cam 60 and moves, and the pressure adjustment member 50 is compressed firmly and the wrinkle suppressing member 52 is attached to the side wall 1.
Press 04. After that, the upper mold 42 further descends to bend and form the bottom wall 102, and the bottom wall 102 and side walls 10
4 is curved in the longitudinal direction, but since the wrinkle suppressing member 52 applies pressure perpendicularly to the side wall 104 as the upper mold 42 descends, the side wall 104 is not wrinkled or warped. As the molding progresses, the curvature of the primary molded product 1, OO becomes larger, and if the side wall 104 is not constrained, compressive stress will occur at the tip of the side wall 104, causing wrinkles, but the upper die 42 will descend. Wrinkle suppressing member 52 or side wall 104
Since the force applied to the molded product 100 becomes large, the molded product 100 is curved mainly due to elongation, and the occurrence of wrinkles is suppressed. Through this molding, the primary molded product 100 is
As shown in FIGS. 1 and 12, a secondary molded product 110 having a concave shape on the bottom wall 102 and the side wall 104 or on the edge side of the side wall 104
It is said that

Next, the secondary molded product 110 is molded by the third molding device 24, and as shown in FIGS. 13 and 14, the longitudinal ends of the pair of side walls 104 are bent outward by approximately 45 degrees. Tertiary molded product 116 with pre-bending portion 114
It is said that In the third forming device 24, as shown on the left side of FIG. 3, as the upper mold 66 descends, the punch 76 is first
The bottom wall 10 is inserted into the secondary molded product 110 together with the groove 68.
2 and the side wall 104 are sandwiched with the tip remaining, and from this state, the upper die 66 or the elastic body 74 is further lowered while compressing, so that the bending blade 78 is lowered relative to the punch 76, and the tip of the side wall 104 is lowered. A pre-bent portion 114 is formed by bending. At this time, the bending line of the preliminary bending portion 114 forms a concave arc shape toward the edge of the side wall 104 .

The tertiary molded product 116 is pressed into the groove 86 of the fourth molding device 26, and as the punch 84 descends, the punched part 94 is first pressed.
fits into the tertiary molded product 116 and sandwiches the side wall 104 with the side wall surface of the groove 86. As the punch portion 94 descends, the pressing surface 96 engages with the edge of the pre-bending portion 114 and the inclined receiver is bent along the edge of the surface 90 to form the flange 16.

After the tip of the pre-bending portion 114 or the inclined support contacts the surface 90, the pressing surface 96 and the inclined support hold the 90 or the flange 16 from both the front and back sides, but in the case of the inclined support, the surface 90 The outer side is inclined upward, and the distance between the holding surface 96 and the inclined receiver is narrower, so that
It is stretched thinner toward the edge. Side wall 1 of secondary molded product 110
The end edge of the side wall 104 will eventually become the end edge of the flange 16 of the product 10, but while the end edge of the side wall 104 has a length of 11, the side wall 104 has a concave curved curve toward the end edge side. If the curve is curved along 12, the curve is longer than pl.
It is. Therefore, if the end edge side +1 of the flange 16 is insufficiently extended and tensile stress remains, the longitudinal center portions of the formed flange 120 will approach each other as shown by the arrows, as shown in FIG. , the ends tend to deform in the direction shown by the arrow B, and the entire part deforms as shown by the dashed line, making it impossible to obtain a highly accurate product. In particular, in the case of high-strength steel, this deformation is likely to occur because the yield point is high.If the end edge side of the flange 16 is extended more as in this example, residual stress can be reduced even in high-strength steel. Therefore, it is possible to obtain a highly accurate product 10 without deformation.

In the above embodiment, the upper surface of the die of the fourth molding device 26 for molding the final product was a sloped surface, or the upper surface of the die 132 was a flat surface as in the fourth molding device 130 shown in FIG. The horizontal receiver is 134, and the punch is 13
Slanted pressing surface 1 that slopes downward toward the outside of the pressing surface 6
It may be set to 38. In this case as well, the inclined pressing surface 138
The inclination angle of the inclination receiver is set to β similarly to the surface 90, so that the end edge side of the flange 16 is forcibly extended more.

Further, in each of the above embodiments, the end edge of the flange 1G is extended over the entire longitudinal direction, but it may be extended partially. In this case, for example, as in a product 140 shown in FIG. 19, grooves 144 are formed at equal intervals in the flange 142, the thickness of which is constant, and the dimension in the longitudinal direction is larger toward the edge of the flange 142. By increasing the thickness of the thinner portion toward the edge of the flange 142, the edge can be extended more.
In order to extend it in this way, a convex portion having a shape corresponding to the groove +44 is provided on the face of the die.

Furthermore, as in the product 150 shown in FIG. 20, the flange 1
Grooves 154 that become deeper toward the end edge of the flange 152 may be formed at equal intervals on the flange 152. In this case, by changing the depth of the groove 154, the end edge side of the flange 152 is extended, and the receiver of the die is provided with a convex portion having a shape corresponding to the groove 154 on its surface.

Further, the flange 16 formed in each of the above embodiments,
142, 152 may be perpendicular to the side wall, or the present invention may be applied to form a flange 162 that is angled relative to the side wall 160 as shown in FIG. In this case, in a molding apparatus having a configuration similar to that for molding the tertiary molded product 116 in the embodiment shown in FIGS. What is necessary is to incline the angle β in a direction approaching the bending surface 172 of the blade 170. Conversely, the bent surface 172 may be inclined toward the outer surface 166, or may be partially extended as shown in FIGS. 19 and 20.

In each of the above embodiments, the flanges were formed using a pair of dies that moved relative to each other in the vertical direction, but the present invention can also be applied to flange forming using a pair of dies that move relative to each other in the horizontal direction. Can be applied.

Furthermore, the present invention is applicable not only to forming a flange by bending the side wall of a groove-shaped member, but also generally to forming a stretch flange by bending the end of a material along a curved line. can.

In addition, the present invention can be implemented with various modifications and improvements based on the knowledge of those skilled in the art without departing from the scope of the claims.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view showing a main part of a fourth forming apparatus among four forming apparatuses used in a flange forming method according to an embodiment of the present invention. FIG. 2 is a front sectional view showing the fourth molding device during molding and at the end of molding. FIG. 3 is a front sectional view showing a state in the middle of molding and a state at the end of molding of the third molding device. FIG. 4 is a front sectional view showing the second molding device, and FIG. 5 is a side sectional view. FIG. 6 is a front sectional view showing the first molding device. FIG. 7 is a perspective view showing a material into which a flange is formed by the above-mentioned flange forming method, and FIG. 8 is a front view. FIG. 9 is a perspective view showing a state in which the above-mentioned material is molded by the above-mentioned first molding device into a primary molded product, and FIG. 10 is a front view. FIG. 11 is a perspective view showing a state in which the secondary molded product is molded by the second molding device to become a secondary molded product,
FIG. 12 is a front view. FIG. 13 is a perspective view showing the secondary molded product formed into a tertiary molded product by the third molding device, and FIG. 14 is a front view. FIG. 15 is a perspective view showing the tertiary molded product formed by the fourth molding device described above into a flanged product, and FIG. 16 is a front view. FIG. 17 is a diagram illustrating warping that occurs in a flange in conventional flange forming. FIG. 18 is a front sectional view showing a fourth forming device used in a flange forming method according to another embodiment of the present invention. FIGS. 19 and 20 are perspective views each showing a flange formed by a flange forming method according to another embodiment of the present invention. FIG. 21 is a front sectional view showing a forming apparatus used in a flange forming method according to yet another embodiment of the present invention. 16: Flange 90 Inclined receiver is surface 142.15
2,162・Flange G 166 Inclined receiver is surface

Claims (1)

[Claims] A method of forming a flange by bending the end of a plate-shaped material along a concave curve inside the edge and toward the edge, in a direction intersecting the plate surface of the flange. The flange is formed by a pair of dies that move relatively, and in the final stage of the flange forming, the flange is sandwiched between the front and back sides by the pair of dies, and in the direction along the curve,
A flange forming method characterized in that the portion closer to the edge is extended more.