JP3280733B2 - Saddle warp reduction mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a saddle warp reducing mold having a function of simultaneously removing and reducing saddle warpage accompanying bending of a plate material by a press brake or the like during bending.

[0002]

2. Description of the Related Art Conventionally, when a plate material is bent by an upper die and a lower die by a press machine such as a press brake, a product obtained by bending the material by the residual stress of the bent material is bent outward ( This is generally referred to as saddle warpage), resulting in poor product accuracy and poor appearance. Therefore, it is required to minimize the above-mentioned saddle warpage.

As a means for reducing such a saddle warp, a bent product (or an intermediate product, hereinafter simply referred to as a product) is corrected by applying a bending force in a direction opposite to the saddle warp by a separate straightening device. Methods are known.

Further, the upper die and the lower die in the press machine are divided into a plurality of parts without using a separate straightening device as described above, and the material is added to the upper die (punch) and the lower die (die). When pressing, a large number of parts are arranged behind the punch and die to apply a part of the pressing force in a direction other than the pressing direction, and a weak fold in the direction opposite to the saddle warpage is applied to the part corresponding to the joint between the punch and the die. An attempt to reduce the saddle warpage by forming a bent portion has already been proposed (JP-A-2-147).
No. 120).

[0005]

However, in order to use a conventional separate straightening device to make the distortion at the bending corners of the product uniform in the entire longitudinal direction, a considerably large straightening force is required. The size of the apparatus is increased, which impairs economical efficiency, and requires extra work steps, resulting in increased construction costs. In addition, a mechanism for dividing the upper mold and the lower mold of the press machine as described above into a plurality of parts and further dispersing the pressing force by both the upper and lower molds at the time of pressing in the longitudinal direction of the work material behind them. If the configuration is such that it is incorporated, there is a problem that the structure of the upper mold and the lower mold is inevitably complicated and the apparatus becomes expensive.

According to the present invention, such a problem is solved, and the warpage is reduced during the bending process of the material plate in the pressing operation without complicating the structure of the mold. The purpose is to provide a mold.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a press die for bending a work by an upper die and a lower die, wherein the lower die is disposed in a longitudinal direction. A plurality of dies are supported by a holding table so as to be slidable in the longitudinal direction, and engagement portions are provided on the bottom surface of these dies in a stepwise manner in order from the center die to the dies at both ends, The inside of the holding table is bisected from the center on both sides, and when slid in the longitudinal direction corresponding to the bottom engaging portion of each of the dies, the dies at the center from the outermost end to the dies at the center are sequentially moved to both ends. Connection rods having engaging portions to be moved are arranged symmetrically, lateral pulling operation pieces are respectively attached to the outer ends of both connection rods, and both ends of the upper die in the longitudinal direction are lowered by a ram. Engage with the horizontal pulling operation piece of the lower mold Characterized in that to is provided an operating piece to move on either side of the two connection rods in the longitudinal direction.

[0008]

According to the saddle warp reducing mold of the present invention thus constituted, when the work is bent between the upper mold and the lower mold, the plurality of dies divided by the lower mold are moved upward. Engagement of the operation pieces attached to both ends of the mold with the horizontal pulling operation pieces attached to the outer ends of a pair of connection rods arranged inside the holding stand of the lower mold. By applying a driving force for laterally pulling, the engaging portions of the connection rods and the engaging portions of the respective dies positioned on the upper side are sequentially engaged in a stepwise manner, and the outermost end of the die is positioned on the center side. Can be moved laterally left and right in order.
Then, the frictional force generated by the repulsive force at the contact surface between the bent work and the die pulls the work to the left and right, and applies a tensile force near the bent portion to generate a saddle warp generated in the work after the pressing force is removed. The phenomenon can be reduced. As a result, the straightening process can be omitted only by the pressing operation.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a mold for reducing saddle warpage according to the present invention will be described with reference to the accompanying drawings. FIG.
FIG. 2 is a front view showing a saddle warp reducing mold of the present invention in a press brake, FIG. 2 is an enlarged sectional end view taken along the line II-II of FIG. 1, and FIG. 3 is a perspective view of a main part.

In these figures, a lower die 10 includes a holding table 11 mounted on a lower die mounting table 1 of a press brake,
A die 15 divided into a plurality of parts supported by the holding table 11
And a pair of elongate dice moving connection rods 18 slidably disposed in the holding table 11 in the longitudinal direction.

As shown in FIG. 2, the holding table 11 is provided with a stepped groove 12 of a required depth along the longitudinal direction, and is divided into a plurality of steps at an upper step 13 of the groove 12. The die 15 is slidably supported. The die 15 is divided into six in this specific example, and these die 15-
The bottom surface 15 'of 1, 15-2, 15-3, 15-4, 15-5, 15-6 is outermost on the left and right sides from the central dies 15-3, 15-4 as illustrated in FIG. End dies 15-1 and 15-6, center dies 15-
Steps 15 "are sequentially formed in a stepwise manner with respect to 3, 15-4.
A connection rod 18 longer than the total length of 15 is slidably disposed at a center in the longitudinal direction. The upper surface of the connection rod 18 has the dies 15-1 and 15-
2, 15-3, 15-4, 15-5, 15-6 are formed in steps from the center side to the outer end side corresponding to the steps 15 "provided on the bottom surface 15 'of each, And the length of each step 18 'is o-a-2t, a-bt, b-c (t for steps o-a, a-b, and b-c in the connected state of the die 15 from the center side. = Gap formed between the dies when the dies are slid and displaced).

A lateral pulling operation piece 31 is fixed to each outer end of the connection rod 18. As this horizontal pulling operation piece 31, an inclined surface having an appropriate angle opening the inside upward.
32 are formed. The upper die 20 formed into a well-known structure and fixed to the lower portion of the ram 2 of the press brake engages the inclined surface 32 of the horizontal pulling operation piece 31 at both longitudinal ends thereof. By the time the mold 20 reaches the final lowering position, the operating portion piece 35 having an operating surface 35 ′ capable of moving the connection rod 18 in the lateral direction by a predetermined dimension via the horizontal pulling operating portion 31 faces downward. It is fixed.
A cam mechanism 30 that slides the connection rod 18 outward on both sides in the longitudinal direction is constituted by the operating portion piece 35 and the lateral pulling operating portion piece 31. Note that, as the cam mechanism 30, the upper die 20 side is positively operated, and the lower die 10
The structure is not limited to the above-described structure as long as the structure can be operated passively and a lateral displacement force can be obtained on the connection rod 18 by engagement of the two. It is also possible to adjust either the operation piece 35 attached to the upper mold 20 side or the horizontal pulling operation piece 31 of the lower mold 10 so that the longitudinal movement amount of the die 15 can be adjusted. is there. In the figure, reference numeral 3 denotes a drive cylinder for raising and lowering the ram, and reference numeral 4 denotes a rod of the drive cylinder.

In the operation mode of the mold of the present invention having the above-described structure, the work W is placed on the lower mold 10 and the drive cylinder 3 is actuated to lower the ram 2 as in the prior art.
The work W sandwiched between the (punch) and the concave portion formed in the die 15 is bent.

At the time of the bending operation of the work W, the inclined surfaces of the two operating portion pieces 35 attached to both ends of the upper mold 20 descending.
35 'is engaged with the inclined surface 32 of the horizontal pulling operation piece 31 of the lower mold 10, whereby the horizontal pulling operation piece on the movable side is applied by a horizontal component force acting on the contact surface between the two inclined surfaces 35' and 32. 31 is extruded longitudinally outward. As a result, the connection rods 18 to which the lateral pulling operation piece 31 is fixed are simultaneously slid outward along the grooves 12 of the holding table 11.

Then, the sliding of the connection rod 18 causes the dies 15-4, 15-5, and 15-6 (in a symmetrical manner) initially in the state shown in FIG. For convenience, only the right half of the lower mold 10 shown in FIG. 1 is shown).
The outermost step 18 'of the 18 and the step 15' of the outermost die 15-6 are engaged to move the die 15-6 outward (FIG. 5B).
reference). During this time, the next step 15 'of the next die 15-5 and the corresponding next step 18' of the connection rod 18 are not in contact with each other. Eventually, when the next step 18 'of the connection rod 18 comes into contact with the step 15' of the die 15-5, the die 15-5 is moved as shown in FIG. 5 (c). This operation is performed symmetrically and simultaneously. As a result, by the time the bending operation of the work W sandwiched between the upper mold 20 and the lower mold 10 (die 15) is completed, the surface of the work W that is gradually bent outside and the die 15 are By using the bending repulsion generated by the above, the left and right tensile forces can be applied to the bending outer portion of the work W in the longitudinal direction by the frictional force generated by the repulsion on the lower mold 10 side. Therefore, a process that can significantly reduce the saddle warpage phenomenon after the processing, which has conventionally occurred during the press bending of the work W, can also be performed.

When the upper mold 20 is lifted after the bending process is performed in this manner, the folded product is removed from the lower mold 10 and left and right until the next processing operation is performed. It is necessary to return the die 15 that has been pulled out and displaced to the original position. The return operation of the die 15 may be manually pushed back via the lateral pulling operation piece 31 (connection rod 18). However, since manual operation is troublesome, the die 15 (horizontal pulling operation piece 31) is required in advance.
As a return means 40, a bracket (not shown) is attached to the end surface of the holding base 11 so as to take a reaction force, and an elastic member such as a coil spring or an air spring is provided between the bracket and the outer end surface of the horizontal pulling operation piece 31. Etc. may be interposed. With such an elastic member, the resistance becomes large to obtain the above-mentioned tensile force. Therefore, a linear actuator (for example, a hydraulic cylinder, a mechanical linear actuator, Depending on the case, a link mechanism or the like may be additionally provided. Further, such a die returning means may be provided in advance on the press machine side.

In the present invention, the engaging portion between the die 15 and the connection rod 18 corresponding thereto is formed by the step 15 'and the step 18'.
Corresponding to In addition, it is also possible to adopt a structure in which a step is formed on one of the engaging portions and an engaging pin is implanted on the other.

[0018]

As described above, according to the present invention, it is possible to reduce the occurrence of warpage during bending by a press machine, improve workability, and greatly reduce the amount of saddle warpage of a press-bent product. It became possible to do. Further, by adjusting the amount of movement of the lower die in the longitudinal direction, the warping direction of the product can be controlled in the opposite direction. And, the bending angle of the formed product has a small amount of springback, and it is possible to easily obtain a highly accurate product having the desired bending angle.

[Brief description of the drawings]

FIG. 1 is a front view showing a mold for reducing saddle warpage of the present invention in a press brake.

FIG. 2 is an enlarged sectional end view taken along the line II-II of FIG.

FIG. 3 is a perspective view of a main part of a mold for reducing warpage of the present invention.

FIG. 4 is a longitudinal sectional view of a lower mold of a mold for reducing a warpage of the present invention.

5A and 5B are diagrams showing an operation mode using the mold for reducing a warpage of the present invention, wherein FIG. 5A shows a relationship between a die and a connection rod before a bending operation is started, and FIG. Fig. 3C shows a state in which the operation of the cam mechanism is started and the dice starts to move laterally, and Fig. 3C shows a state in which the dice is moved most laterally.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Lower die mount 2 Ram 10 Lower die 11 Holder 12 Groove 13 Step 15 Die 15 'Bottom of die 15 "Step provided on die 18 Connection rod 18' Step provided on connection rod 20 Upper die 30 Cam Mechanism 31 Side pulling operation piece 32 Slope 35 Operating piece 35 'Operation surface W Work

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B21D 5/02

Claims (3)

(57) [Claims] 1. A press die for bending a work by an upper die and a lower die, wherein the lower die is a holding base such that a plurality of dies divided in the longitudinal direction are slidable in the longitudinal direction. At the bottom surface of these dies, engaging portions are provided in a stepwise manner in order from the center die toward the opposite dies, and the inside of the holding table is divided into two sides from the center to each of the dies. Connection rods having an engagement portion for sequentially moving the center die to both end sides from the outermost die to the both ends when slid in the longitudinal direction corresponding to the bottom engagement portion are symmetrically arranged. At the outer ends of both connection rods, horizontal pulling operation pieces are respectively attached,
At both ends in the longitudinal direction of the upper mold, operating parts are provided which are engaged with the horizontal pulling operation parts of the lower mold when the ram is lowered by the ram to move the connection rods to both sides in the longitudinal direction. Characteristic mold for reducing saddle warpage. 2. The saddle warpage reducing mold according to claim 1, wherein the engaging portion provided on the bottom surface of the die and the engaging portion provided on the connection rod are steps formed in corresponding steps. . The outer portion of claim 3 wherein said lower mold the lateral pulling operation piece of ram in conjunction with being raised according to claim 1 which is attached a die return means for returning the connecting rod Saddle warp reduction mold.