JP3194407B2 - Pressing method and press mold device for sheet metal work - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press method and a press die apparatus for press-forming a hat-shaped sheet metal work such as a side member of an automobile from a strip-shaped sheet metal material.

[0002]

2. Description of the Related Art A hat-shaped sheet metal work 1 'as shown in FIG. 5, for example, is used as a side member fixed to the left and right sides of the upper surface of a floor panel of an automobile. Such a hat-shaped sheet metal work 1 ′ has a main body part a having a U-shaped cross section and flange parts b extending from both ends of the main body part a, and for example, a press die apparatus as shown in FIGS. 6 and 7. Press molded using

The press die apparatus shown in FIG. 6 includes a fixed lower die 25 and an upper die 26 that moves up and down. Lower mold 25
Has a square bar-shaped convex portion 27 on the upper surface that fits the inner surface of the main body portion a of the hat-shaped sheet metal work 1 ′. The lower die 25 is provided with an elevating rod 28 that vertically moves through the lower die 25. A blank holder 29 is fixed to the upper end of the lifting rod 28, and the lower curved blade 30 for clamping the work is fixed to the blank holder 29. The upper mold 26 has, on the lower surface, a concave portion 32 having a U-shaped cross section which fits the outer surface of the main body portion a of the hat-shaped sheet metal work 1 ′,
It has an upper curved blade 31 facing the lower curved blade 30. A holding blade 33 is housed in the depth of the recess 32 via a spring material 34.

A band-shaped sheet metal material 1 shown in FIG. 7 is press-formed into a hat shape by a lower mold 25 and an upper mold 26. That is, the lifting rod 28 of the lower mold 25 is lifted and the blank holder 29
Is held at a position slightly higher than the convex portion 27, and the lower curved blade 30 of the blank holder 29 and the upper curved blade 31 of the upper die 26 are held.
, One end of the sheet metal material 1 in the width direction is firmly clamped from above and below, and the other part of the sheet metal material 1 is placed in a free state.
The upper mold 26 is lowered in the state shown in FIG.
7, the center of the sheet metal material 1 in the width direction is formed in the concave portion 32 of the upper die 26.
Pushing in while squeezing, it presses against the holding blade 33 in the concave portion 32 to obtain the state shown in FIG. In the state of FIG.
Is press-formed in a U-shape as a main body portion a of the hat-shaped sheet metal work 1 ′, and both end portions of the sheet metal material 1 are press-formed as flange portions b of the hat-shaped sheet metal work 1 ′.

[0005]

Problems to be Solved by the Invention From the state of FIG.
5, the central portion of the sheet metal material 1 is
2. When a strong ironing force is required to push the steel sheet into the metal sheet 2, the frictional heat generated by the strong ironing at this time causes seizure of the sheet metal material 1 to the press die, causing a line stoppage in the pressing process, There was a problem that the life of the press die was shortened.

[0006] As a solution to such a problem, a method has been used in which a press die is coated with oil to reduce frictional resistance at the time of pressing a sheet metal material, thereby suppressing generation of frictional heat. However, the effect of suppressing frictional heat by applying oil is thin,
There is a problem that it is difficult to extend the life of the press die, and the work for applying the oil is troublesome, and the workability of the sheet metal material pressing process is deteriorated.

Further, in order to extend the life of the press die, it has been performed in some cases to make the press die, particularly the curved blade, a material excellent in heat and wear resistance and to perform a special heat treatment. However, even if the curved blade of the press die is made of a heat-resistant and abrasion-resistant material, there is a problem in durability against a large ironing force at the time of pressing the sheet metal material, and it is difficult to extend the life of the press die. There is a problem that a curved blade made of a heat-resistant and abrasion-resistant material is expensive and the running cost is increased.

When the band-shaped sheet metal material 1 shown in FIG. 7 is press-formed into a hat shape, depending on the material of the sheet metal material 1,
At the time of demolding after press forming, both side walls of the U-shaped main body portion a of the hat-shaped sheet metal work 1 ′ may expand due to spring back, and a problem that the hat shape may not be obtained may occur.

An object of the present invention is to provide a pressing method and a long-life press die apparatus which generate almost no frictional heat when press-forming a strip-shaped sheet metal material into a hat-shaped cross section. .

[0010]

The invention according to claim 1 of the present invention.
Presses a strip-shaped sheet metal material with a male lower mold and a female upper mold to form a main body having a U-shaped cross section in the width direction and flanges extending from both ends of the main body in the width direction. The lower die is formed by press-forming a hat-shaped sheet metal work composed of a part , and the lower die extends from the root of the square bar-shaped protrusion along the inner surface of the main body of the hat-shaped sheet metal work. The upper mold has a flange forming surface along the lower surface of the flange portion of the hat-shaped sheet metal work, and the upper mold has an upper part of the main body of the hat-shaped sheet metal work as the convex part of the lower mold.
Pad having a lower surface to be pressed with , and both sides of the pad
Are rotatably disposed back and forth in the way, and a pair of tracks blades having a pressing surface of the substantially L-shaped cross-section along the flange top surface from the outer surface of the main body portion side walls of the hat-shaped sheet metal work on the front, the pad
Has a concave surface of an inner surface along the upper surface of the main body of the hat-shaped sheet metal work and the upper edge of the outer surface of both side walls at the center of the lower surface ,
When pressing the center part in the width direction of the band-shaped sheet metal material with the upper surface of the lower die and the upper surface of the upper die, both sides of the main body of the hat-shaped sheet metal work are formed by the concave surface of the lower surface of the pad and the upper end of the convex portion. After roughly bending the two corners of the upper edge of the wall, a pair of curved blades are advanced to move both ends of the rough-bent sheet metal material except for the center in the width direction with the pressing surface of the curved blade. It is characterized in that it is simultaneously pressed against the side surface of the convex portion and the surface on which the flange is formed, and press-formed into an L shape.

In executing the above pressing method ,
On the side of the flange forming surface of the lower die, a sliding surface is provided which is inclined downward on the flange forming surface side, and a suspension cam supporting the curved blade on the front surface is connected to the lower surface of the upper die so as to be able to move back and forth, and descends. It is desirable to move the curved blade forward by pressing the suspension cam on the slide surface of the lower die with the upper die and sliding the slide surface.
No.

Further, the invention of claim 2 of the present invention, in order to prevent deformation due to spring back caused by the material of the hat-shaped sheet metal work, the both side surfaces of the convex portion of the lower die, hat-shaped to be press-formed A tapered side surface is formed at an angle that allows for the amount of springback of both side walls of the U-shaped main body of the sheet metal work.

[0013]

[Function] By pressing the widthwise central portion of the band-shaped sheet metal material with the upper surface of the lower mold convex portion and the concave surface of the upper mold pad, the central portion in the width direction of the sheet metal material is roughly bent without being squeezed. The upper and lower sides of the main body of the hat-shaped sheet metal work are formed into two corners, and thereafter, a pair of curved blades are moved forward to form a roughly bent sheet metal material except for the center in the width direction. The end is pressed simultaneously to the side surface of the lower mold and the flange forming surface without being squeezed by the pressing surface of the curved blade, pressed into an L-shape, and formed into both sides of the main body of the hat-shaped sheet metal work. As a result of forming the flange portion, frictional heat hardly occurs in a series of press forming.

Further, both ends of the sheet metal material other than the center in the width direction are simultaneously pressed against the side surfaces of the convex portion of the lower die and the flange forming surface by a pair of curved blades of the upper die and press-formed into an L shape. This makes it possible to make both side surfaces of the lower mold convex portion a taper surface having a negative angle in consideration of the amount of springback of both side walls of the main body of the hat-shaped sheet metal work. Can be prevented from being deformed by springback.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a press die apparatus for press-forming a hat-shaped sheet metal work 1 'in FIG. 5 will be described with reference to FIGS. 1 to 3, and a second embodiment will be described with reference to FIG. I do.

The press die apparatus of the first embodiment shown in FIG. 1 includes a fixed lower die 2 and an upper die 6 that moves up and down. The lower mold 2 includes a square bar-shaped convex portion 3 in the center of the upper surface, and a convex portion 3.
Flange forming surface 4 extending in the orthogonal direction from the lower end of both side surfaces of
Having. The convex part 3 forms the inner surface of the main body part a having a U-shaped cross section of the hat-shaped sheet metal work 1 ′ on the upper surface and both side surfaces. The flange forming surface 4 forms the lower surfaces of the flange portions b at both ends in the width direction of the hat-shaped sheet metal work 1 ′. Further, at both end portions of the upper surface of the lower mold 2, tapered sliding surfaces 5 descending in the direction of the convex portions 3 are formed.

The upper die 6 has a pad 7 at the center of the lower surface and a pair of curved blades 12 at both ends of the lower surface. Pad 7 is upper mold 6
Guide key 1 in a groove 14 formed vertically in the center of the lower surface of the
It is stored so as to be able to move up and down guided by 5. A spring member 16 is mounted between the pad 7 and the top surface of the groove 14, and the pad 7 always receives a biasing force downward with the spring member 16. Pad 7
Has a concave surface 8 at the center of the lower surface. The concave surface 8 has a shallow groove shape along the upper surface of the main body portion a of the hat-shaped sheet metal work 1 ′ and the upper edge of the outer surface of both side walls.
Are inserted so as to protrude downward. A spring material 17 is mounted between the push pin 9 and the top surface of the groove 14, and the push pin 9 always receives elasticity downward by the spring material 17.

A hanging cam 11 is connected to each of a pair of blocks 10 projecting from both ends of the lower surface of the upper die 6, and a curved blade 12 is fixed to a front portion of the pair of hanging cams 11. A tapered slide member 18 is attached to the lower surfaces of the pair of blocks 10 so as to face each other, and a suspension cam 11 is mounted on the slide member 18 so as to be slidable in the vertical and oblique directions of the slide member 18. . A spring member 19 is mounted between each suspension cam 11 and the lower surface of the lower mold 2, and the suspension cam 11 always receives elasticity downward by the spring member 19. When the upper mold 6 is lowered toward the lower mold 2,
The lower surface of each suspension cam 11 rides on the slide surface 5 of the lower mold 2,
When the upper die 6 is further lowered, the suspension cam 11 is pressed against the slide surface 5 and moves forward along the slide surface 5 in a direction in front of the lower slope of the slide surface 5, that is, the pair of suspension cams 11 approach each other. The curved blade 12 is fixed so as to project from the front surface of the suspension cam 11.

The curved blade 12 is formed of a substantially square bar-shaped wear-resistant metal, and has a pressing surface 13 composed of two substantially orthogonal surfaces, a front surface and a lower surface. The pressing surface 13 has a shape along two orthogonal surfaces of the convex portion 3 of the lower die 2 and the flange forming surface 4. The outer surface of the main body portion a of the hat-shaped sheet metal work 1 ′ and the upper surface of the flange portion b are simultaneously formed. Press. The pair of curved blades 12 make a forward movement approaching each other and a backward movement moving away from each other.

The press die apparatus shown in FIG. 1 operates as shown in FIGS. 2 and 3 to press-form a strip-shaped sheet metal material 1 into a hat shape. FIG. 2 shows a state in which the upper die 6 is at the position of the top dead center with respect to the lower die 2, and in this state, the projections 3 of the lower die 2 are shown.
When the central portion in the width direction of the band-shaped sheet metal material 1 is placed thereon, the pad 7 of the upper die 6 descends, and the push pin 9 projecting from the concave surface 8 of the pad 7 causes the center of the sheet metal material 1 to protrude. 3, the sheet metal material 1 is positioned and held on the projection 3. At this time, the pair of suspension cams 11 and the curved blades 12 of the lower die 2 are
It is in the standby position where it has receded to both sides from the lower part of the protrusion.

In the state shown in FIG. 2, the upper die 6 descends, and first, the central part of the sheet metal material 1 is pressed at the concave surface 8 of the pad 7 and the upper end of the convex part 3 of the lower die 2 so that the sheet metal material 1 is drawn. Rough bending is performed as shown in FIG. That is, the central part of the sheet metal material 1 is
By pressing the upper surface and both corners of the upper surface with the concave surface 8 of the pad 7, only the two corner portions c of the main body portion a of the hat-shaped sheet metal work 1 'in FIG. Both end parts except the part are bent in a C shape (FIG. 3). In such a rough bending forming of only the central portion of the sheet metal material 1, frictional heat hardly occurs. The upper die 6 further descends while the sheet metal material 1 is roughly bent and the lower surface of the suspension cam 11 abuts on the slide surface 5 of the lower die 2. At this point, the curved blades 12 of the pair of suspension cams 11 are located on the sides of the C-shaped side end of the sheet metal material 1 that has been roughly bent.

In the state shown in FIG. 3, the upper die 6 is further lowered, and the pair of suspension cams 11 are pressed against the slide surface 5 of the lower die 2. Thereby, the pair of suspension cams 11 advance by the cooperation of the horizontal component force received from the slide surface 5 and the inclined slide member 18 of the block 10, and the pair of curved blades 12 advance. In this way, the suspension cam 11 of the upper die 6 is slid along the slide surface 5 of the lower die 2 to advance the curved blade 12, whereby the curved blade 1 is moved.
2 moves smoothly, and the sheet metal material 1 described below
Can be pressed stably.

Two orthogonal pressing surfaces 13 of the curved blade 12 to be advanced
As a result, the C-shaped side end portion of the sheet metal material 1 is simultaneously pressed against the side surface of the convex portion 3 of the lower die 2 and the flange forming surface 4 while being bent into an L shape. As shown in FIG. 1, the curved blade 12 that has advanced
The projection 3 is inserted between the pad 7 and the flange molding surface 4.
Hat-shaped sheet metal work 1 '
Of the main body part a and the flange part b are simultaneously press-formed. Since this press forming is performed without substantially squeezing the sheet metal material 1, there is almost no generation of frictional heat.

Incidentally, depending on the material of the sheet metal material 1 and the pressing conditions, both side walls of the main body portion a of the sheet metal work 1 'press-formed into a hat shape may be formed into a C-shape by springback at the time of demolding after the press forming. May spread. As a measure for preventing work deformation due to such springback, both sides of the convex portion 3 of the lower mold 2 are formed into inverted C-shaped tapered side surfaces 20 as in the press mold apparatus of the second embodiment shown in FIG. The front surface of the curved blade 12 is formed as a tapered pressing surface 21 corresponding to the tapered side surface 20. The negative angle θ formed by the tapered side surface 20 with respect to the vertical line on the lower mold 2 is set to an angle that allows for the amount of springback of both side walls of the main body portion a of the sheet metal work 1 ′.

FIG. 4 shows a state in which the central portion of the strip-shaped sheet metal material 1 is roughly bent by the pad 7 of the upper die 6 and the convex portion 3 of the lower die 2. The blade 12 advances, and presses both ends of the sheet metal material 1 into a substantially L-shape as shown by a chain line in FIG. Tapered side surface 20 of convex portion 3 and curved blade 12
The side end portion of the sheet metal material 1 pressed by the tapered pressing surface 21 is press-formed at a negative angle θ. After this press forming, when the pair of curved blades 12 are retracted and separated from the substantially L-shaped both ends of the sheet metal material 1, the both ends of the sheet metal material 1 spring back, and the negative angle θ becomes zero. Is a predetermined parallel shape.

[0026]

According to the present invention, the center of the band-shaped sheet metal material in the width direction is pressed by the upper surface of the lower mold convex portion and the concave surface of the upper mold pad, so that the central portion of the sheet metal material in the width direction is pressed. Rough bend forming without squeezing, and both ends excluding the center in the width direction of the sheet metal material formed by rough bending by a pair of curved blades are not squeezed by the pressing surface of the curved blade. Since the predetermined hat-shaped sheet metal work is pressed simultaneously to the convex side surface and the flange forming surface of the lower mold and pressed into an L shape and the predetermined hat-shaped sheet metal work is pressed, almost no frictional heat is generated in a series of press forming, As a result, seizure of the press die sheet material to the press die is eliminated, and troublesome work such as applying oil to the press die becomes unnecessary, and the efficiency of the production line of the press process can be improved, Furthermore, the press mold must be made of a material that is particularly excellent in heat and wear resistance. Without, the life of the press die, cost reduction can be achieved.

Further, since the lower mold is pressed against the side surface of the lower mold with the curved blade of the upper mold and press-formed, the side surface of the lower mold is formed into a taper side with a negative angle in consideration of the springback amount of the sheet metal material. This makes it possible to prevent a press-formed sheet metal work from being deformed by springback, thereby providing a press die apparatus capable of forming a hat-shaped sheet metal work having a stable shape.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an embodiment of the present invention during press forming of a sheet metal material.

FIG. 2 is a sectional view of the apparatus of FIG. 1 immediately before pressing a sheet metal material.

3 is a cross-sectional view of the apparatus shown in FIG. 1 when a sheet metal material is roughly bent and pressed.

FIG. 4 is a sectional view of a main part showing another embodiment of the present invention.

FIG. 5 is a perspective view showing an example of a hat-shaped sheet metal work.

FIG. 6 is a cross-sectional view of a conventional press die apparatus for press-forming the sheet metal work of FIG.

FIG. 7 is a sectional view of the apparatus in FIG. 6 immediately before pressing a sheet metal material.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sheet metal material 1 'Sheet metal work 2 Lower die 3 Convex part 4 Flange forming surface 5 Slide surface 6 Upper die 7 Pad 8 Concave surface 11 Hanging cam 12 Curved blade 20 Tapered side surface

Continuation of the front page (56) References JP-A-7-284854 (JP, A) JP-A-4-172128 (JP, A) JP-A-6-246355 (JP, A) , U) Japanese Utility Model Application 2-138013 (JP, U) Japanese Utility Model Application Showa 59-124619 (JP, U) Japanese Utility Model Application Utility Model 4-108915 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB (Name) B21D 5/01

Claims (2)

(57) [Claims] 1. A band-shaped sheet metal material is pressed by a male lower mold and a female upper mold to extend from a main body part having a U-shaped cross section in the width direction and both ends in the width direction of the main body part. the hat-shaped sheet metal work consisting flange portion standing in a method of press molding, the convex portion of the square bar wherein the lower mold along the body inner surface of the hat-shaped sheet metal work, extending laterally from the base of the convex portion The upper die has an upper part of a main body of the hat-shaped sheet metal work and a lower part of the main body of the hat-shaped sheet metal work.
A pad having a bottom surface pressing at the convex portion of the mold, the path
And a pair of curved blades having a pressing surface having a substantially L-shaped cross section extending from the outer surface of both side walls of the main body portion of the hat-shaped sheet metal work to the upper surface of the flange portion at the front portion. The pad has an inner concave surface along the upper surface of the main body of the hat-shaped sheet metal work and the outer upper edges of both side walls of the main body at the center of the lower surface.
A hat-shaped sheet metal work is formed by pressing the central portion in the width direction of the band-shaped sheet metal material with the upper surface of the lower mold and the upper surface of the lower surface of the pad. After roughly bending the two corners of the upper edges of both side walls of the main body, a pair of curved blades are advanced to press the curved edges on both sides excluding the center in the width direction of the roughly bent sheet metal material. A method for pressing a sheet metal work, wherein the surface is simultaneously pressed against the side surface of the convex portion of the lower mold and the flange forming surface to press-form the plate into an L shape . 2. A strip-shaped sheet metal material is pressed by a male lower mold and a female upper mold, and a main body having a U-shaped cross section in the width direction is extended from both ends in the width direction of the main body. the hat-shaped sheet metal work consisting of a flange portion for standing a device for press molding, extending the convex portion of the square bar wherein the lower mold along the body inner surface of the hat-shaped sheet metal work, from the base of the convex portion in the transverse The hat-shaped sheet metal work has a flange forming surface along the lower surface of the flange part, and the upper die is positioned in front of the upper part of the main body of the hat-shaped sheet metal work.
A pad having a lower surface to be pressed with the convex portion of the lower die ,
A pair of curved blades which are disposed so as to be able to move back and forth on both sides of the pad, and which have a pressing surface with a substantially L-shaped cross section along the flange surface from the outer surface of the main body side wall of the hat-shaped sheet metal work at the front. The pad has an upper surface of the main body portion of the hat-shaped sheet metal work and a concave surface having an inner surface shape along an outer upper edge portion of both sides of the main body portion at a central portion of the lower surface , so that the width direction of the band-shaped sheet metal material is reduced. When the central part is pressed with the upper surface of the lower die and the upper surface of the pad of the upper die, the two corners of the upper edges of both side walls of the main body of the hat-shaped sheet metal work are roughened by the concave surface of the lower surface of the pad and the upper end of the convex portion. After bending, a pair of curved blades are moved forward, and both ends of the rough-bent sheet metal except for the center in the width direction are simultaneously pressed by the curved blade pressing surface to the lower mold convex side surface and the flange forming surface. to a press die apparatus that pressed into the pressing to L-shaped, the convex portion of the lower die Sides, hat-shaped to be press-formed
Spring back on both side walls of U-shaped main body of sheet metal work
Characterized by a tapered side surface with a negative angle that allows for the amount
Press die equipment for sheet metal work.