JPS608889B2 - Press stretch forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a press stretch-forming device that presses a blank while holding and pulling both sides of the blank.

Generally, when press-forming a blank (plate-shaped material) with shallow drawing, when the workpiece is removed from the mold, the processed shape of the plate returns slightly, causing a so-called springback phenomenon in which the shape no longer matches the desired shape. As a countermeasure (Fig. 3), gripping claws b,
Stretch forming is performed by clamping at point b and molding the molds c and d together.

However, since the gripping claws b that clamp the blank a are fixedly installed apart from each other on both sides of the molds c and d, the gripping claws from the finished periphery e of the blank a to the fixed end in the gripping claws b are There is a drawback that the material removal size g is required, which increases the margin f, and the yield is extremely poor. The present invention has been made in view of these drawbacks, and includes two clamping means for clamping a blank that can be moved forward and backward with respect to a mold, and a blank clamping means for clamping a blank in a mold by opening and closing arms of the two clamping means. The opening/closing arms are automatically moved outward at both ends of the upper die that is gripped and lowered to keep the blank taut, and the blank is press-formed in the latter half of the lowering stroke of the upper die to adjust the material removal size. The purpose of the present invention is to provide a stretch forming device that enables forming processing of blanks with reduced amount.

Hereinafter, the configuration of the present invention will be explained in detail with reference to one embodiment.

As shown in FIGS. 1 and 2, 1 is a stretch forming device, which includes a press machine (not shown) equipped with a mold 4 consisting of an upper mold 2 and a lower mold 3 for forming. , includes as main components clamping means 6, 6 for fixing and tensioning the blank 5, only one side of the clamping means 6 being shown in FIG. The above 2 and the lower mold 3 have sloped surfaces 7 on both sides in the direction in which the blank 5 is pulled.
, 8, and when the mold is closed, a V-shaped space 9 is formed by the inclined surfaces 7, 8 along the split surfaces 10, 11.

The clamping means 6 includes a fixed claw member 12, a movable claw member 13, and a fulcrum shaft 14, and its outer surface is aligned with the inclined surface 7.
An opening/closing arm 1 formed in a chevron-shaped cam shape that slides on , 8
5, a toggle joint 21 formed by combining links 16, 17, pivot pins 18, 19, and connection pin 20, a forward/backward cylinder 22 that opens and closes the opening/closing arm 15 via the toggle joint, and the forward/backward cylinder. a support arm 23 supporting the base end of the fixed claw member 1;
Frame 2 that supports a mounting seat 24 mounted on the base of 2.
5, and the clamp means 6, 6 are arranged facing each other on the inclined surface 8 of the lower mold 3, and the tip of the fixed claw member 12 of the opening/closing arm 15 is in sliding contact with the inclined surface 8 of the lower mold 3. The frames 25 are biased toward each other by a spring (not shown) provided at the bottom thereof, and are provided so as to be movable in the lateral direction.

Reference numerals 26 and 26 designate clamp release means that are provided with inclined cam surfaces 27 and 27 and are fixedly installed below the connecting pins 20 and 20.

Next, the operation of the device of the present invention will be explained.

The forward/backward cylinders 22, 22 of both the clamp means 6, 6 are driven backward in advance to open the opening/closing arms 15, 15, and then both ends of the blank 5 are accommodated in the openings of the opening/closing arms 15, 15. After that, each advancing/retracting cylinder 22, 22
is driven forward to close both opening/closing arms 15, 15, and grip and fix the blank 5. Subsequently, the upper mold 2 is lowered to move the inclined surface 17 to the movable claw member 1 of both opening/closing arms 15, 15.
3, 13 (upper side in Figure 1)
(Fig. ■) After the upper mold 2 is lowered, the upper mold 2 continues to move downward, so that the upper mold 2 has sloped surfaces 7, 7 and the lower mold 3 has sloped surfaces 8, 8. Tsumebe Village 12,1
Both the clamping means 6, 6 are moved laterally by pressing the outer surface of the blank 5, and the blank 5 is continued to be pulled so as to exceed the elastic region (Fig. 1 (■)).

Press forming continues with the lowering of the upper die 2 (the first
When the lowering movement of the upper die 2 approaches the end point, the connecting pins 20, 20 of the clamping means 6, 6 come into contact with the cam surface 27 of the clamp release means 26, and then are guided by the cam surface. The connecting pins 20, 20 press the advancing/retracting cylinder 22 to move it backward (the chain line position in Fig. 1), and the opening/closing arm 15,
15 is opened to release the blank 5, and the pressed product is placed in the mold 4.
taken out from within. Further, as described above, the clamping means 6, 6 in the pressing process are urged toward each other by the spring IJ ring (not shown) provided at the lower part of the frame 25, and are movable laterally. It is provided. As a result, during pressing, a force is applied in the lateral direction to the clamping means 6, 6 due to the lowering movement of the upper die.
This force moves the clamping means 6, 6 away from each other via the frame 25 against the biasing force of the spring. In the above embodiment, the clamping means 6, 6 are moved laterally by providing the frame 25 so as to be movable; may be provided so as to be laterally movable.

With the above configuration, the present invention clamps the blank with the clamping means that has entered the inside of the mold, and the lateral movement of the clamping means to apply tension to the flank is performed by using the lowering movement of the upper mold. This is done by sliding the inclined surface of the shape and the cam surface of the opening/closing arm, and press forming is performed while maintaining this state, so the blank gripping margin f2 and material removal size saddle are significantly reduced, improving blank yield. In addition, there is no need for a drive means to move the clamping means laterally, and the work space around the press can be used more effectively, which has the excellent effect of significantly improving work efficiency and productivity. be.

[Brief explanation of the drawing]

The drawings illustrate an embodiment of the device of the present invention, FIG. 1 is a front view showing one side of the stretch forming device and explaining its operation, FIG. 2 is a blank diagram of this embodiment, and FIG. 3 is a blank diagram of a conventional example. FIG. 1...Stretch forming device, 2...
...Upper die, 3...Lower die, 5...Blank, 6...Clamp means, 7, 8...Slanted surface, 9... ...Space, 15...Opening/closing arm,
25...Frame. Figure 2 Figure 3

Claims (1)

[Claims] 1 Equipped with an upper mold and a lower mold for molding, both sides of the upper mold and the lower mold in the blank pulling direction are formed with inclined surfaces, and a space that becomes V-shaped when the mold is closed is formed along the split surface. Clamping means supported by a frame are arranged facing each other on the inclined surface of the lower mold, and the clamping means are provided so as to be movable and biased toward each other, and the opening/closing arms of the clamping means is formed in a chevron-shaped cam shape that slides on the sloped surfaces of the upper and lower molds, clamps the blank above the lower mold, and uses the lowering movement of the upper mold to lower the slope of the upper and lower molds. A stretch forming device for a press, characterized in that a clamping means is moved laterally on a surface to pull a blank.