[0033] Attached below Figure 1-14 An embodiment of the present invention is described.
[0034] A special mold for stamping internally bent parts. It has a first mold assembly and a second mold assembly. The first mold assembly includes a male mold I1, a female mold I2, a mold upper plate 3, a fixed plate 4, a cushion frame 5, and a mold. Lower plate 6 and ejector 7, said punch I1 with relief grooves 9 on both sides of the lower end; said second mold assembly includes punch II12, female mold II13, mold handle II14, mold base 15, and lower mold plate 16. And the crowbar 17, the lower part of the punch II 12 is made with a V-shaped transition section 20, the lower part of the V-shaped transition section 20 is made with a straight section 21, and one side of the straight section 21 is made with an inclined stamping section below 22. The lower part of the inclined stamping forming section 22 is formed with a direct pressure forming section 23, and the bottom of the direct pressing forming section 23 is formed with a forming fillet.
[0035] The above-mentioned fixing plate 4 is fixed on the lower end surface of the upper plate 3 of the mold, the punch I1 passes through the mold fixing plate 4 and the upper end of the punch I1 fits with the sink groove 8 on the fixed plate 4, and the female mold II2 is matched with the cushion frame 5 and the lower mold plate 6 are fixedly connected, the ejector device 7 is placed in the through hole of the cushion frame 5 and the concave mold II2, and the lower part of the ejector device 7 is in contact with the ejector rod 10 passing through the mold lower plate 6; The upper end surface of the upper plate 3 of the mold is fixed with a mold handle I11; the upper part of the punch II12 is placed in the inner hole of the mold handle II14 and the two are fixedly connected. The inner cavity of the punch II12 is provided with a pressing device 18 and a pressing device The lower end of the 18 protrudes from the lower end surface of the male mold II12. Specifically, the pressing device 18 is composed of a screw plug 27 and a spring 28. The inner cavity of the male mold II12 is a screw hole. The screw plug 27 is adapted to the screw hole, and the spring 28 It is sleeved on the upper end of the pressing rod 29 and pressed against the lower end surface of the screw plug 27, and the lower end of the pressing rod 29 extends out of the lower end surface of the punch II12. The backing plate 19 is fixed on the upper end surface of the lower mold plate 16, the mold base 15 is fixed on the upper end surface of the backing plate 19, the concave mold II 13 is placed in the mold base 15 and the cavity of the concave mold II 13 is provided with a top pin 24, and one end of the backing plate 19 A slot is formed, one end of the crowbar 17 is pressed against the lower end of the top pin 24 through the slot, and the crowbar 17 is hinged to the backing plate 19 via a cylindrical pin 26.
[0036] The upper end of the above-mentioned punch II12 is provided with a groove-shaped transverse through hole 30, the hanging plate 31 crosses the groove-shaped transverse groove-shaped through hole 30, the screw passes through the mold handle II14 and the screw hole 32 on the hanging plate 31 is screwed, the horizontal cylindrical pin 33 Stop the rotation of the punch II12 and the mold handle II14; the crowbar 17 is composed of a long arm 34 and a short arm 35, both of which are in an L-shaped structure. The short arm 35 is pushed against the lower end of the top pin 24 after being slotted. The short arm 35 is hinged to the backing plate 19 by a cylindrical pin 26 as a whole, the long arm 34 is a free end, and a spring and its positioning pin 36 are provided at the lower part thereof, and the spring and its positioning pin 36 are under the long arm 34 When pressing, it is adapted to the blind hole 25 made on the lower template 16.
[0037] The crowbar 17 is equipped with a rotating shaft cylindrical pin 26, assembled in the backing plate 19, and integrated with the backing plate 19, and can rotate around the rotating shaft cylindrical pin 26, which can move the top pin 24 upwards and eject the bent part 37; the spring and its The positioning pin 36 can reset the crowbar 17 to the initial state to facilitate the placement and positioning of the processed part 37; the positioning pin can position the spring 36 so as not to fall off.
[0038] A stamping method for stamping internally bent parts is also provided, which includes the following steps:
[0039] 1) Blanking: Calculate the unfolding size of the blank of the stamping part, and use the blanking die to punch the blank. Figure 5 Shown
[0040] 2) V-shaped bending: Use a bending die to bend both ends of the blank to make both ends of the blank into a V-shaped structure. Image 6 As shown; when the two ends of the blank form a V-shaped structure, the included angle is 60°.
[0041] 3) U-shaped pre-bending: the first mold assembly is used to pre-bend the V-shaped bending blank at both ends, so that the blank is bent into a U-shaped structure, and the inner fillet of the bottom of the forming at both ends of the blank is consistent with the round corner of the punch. Figure 7 Shown
[0042] 4) Cantilever combined inner bending: U-shaped pre-bent blanks are used for cantilever combined bending with the second mold assembly, and the blank is bent into a shape that meets the size requirements while ensuring that the inner fillet of the bottom remains unchanged. Figure 8 Shown.
[0043] U-shaped pre-bending simulation calculation, force analysis of cantilever combined inner bending die, design feasibility analysis:
[0044] 1. The influence of the V-shaped bending angle on the strength of the U-shaped pre-bending punch in the subsequent process. When the V-shaped bending angle is changed from 45° to 60°, the thickness of the bending fillet R0.8 at the bottom of the pre-bending gradually increases and the strength Gradually increase, but after the two sides are bent, the opening in the middle is gradually reduced, so that the middle part of the U-shaped pre-bending punch in the subsequent process is thinned, and the punch strength is reduced, and the pressing distance of the U-shaped pre-bending punch press is reduced. , After simulation calculation, 60° is relatively good, and the bottom bend and fillet and the middle stiffener are both considered ( Image 6 Shown).
[0045] 2. For the force analysis and design feasibility analysis of the internal bending of the cantilever assembly, the workpiece 37 is bent in the initial state of the cantilever assembly. Before the punch Ⅱ12 bends the part 37, the pressing rod 29 of the pressing device 18 first presses the bottom of the part 37. F 3 Is the pressing force of the pressing device 18, F 4 It is the reaction force of the ejector pin 24; when the punch Ⅱ12 descends, the punching force acts on the part 37, generating a positive pressure F 1 , The maximum bending moment is generated at point A of the bending part 37, the part 37 is bent and deformed around point A, and the reaction force F is generated at point B of the corner of the die Ⅱ13 2 , Using this as the fulcrum to produce the maximum bending moment, so that the workpiece 37 bends and deforms around point B; positive pressure F 1 Under the action, the workpiece 37 uses point B as the fulcrum, so that the side wall and bottom have an upward rotation trend, F 3 The pressing force of the pressing device 18 is to balance the reaction force of this trend, and to stabilize the positioning of the work piece 37 inside the die Ⅱ13, to ensure the stable forming size and dimensional accuracy of the part 37, and the right side of the part 37 is bent by force. Since the curved fillet at the bottom of the part 37 is relatively small relative to the thickness of the material, the rigidity and strength are good, the downward force generated by the pressing force on the side wall of the part 37 is not enough to change the bottom fillet R0.8 that has been bent and formed; Die Ⅱ12 is stamped to the end, and all the bending forming parts are corrected and shaped. The force characteristic of the workpiece 37 in the second mold assembly is that in a small space, the floating and cantilever combination is bent, such as Figure 13 , Figure 14 Shown.
[0046] 3. The actual test mold parts are more stable in size and higher precision than the imported samples, especially the bottom rounded corners are better than the imported samples. The bottom rounded corners of the imported samples are not guaranteed, and they are non-cylindrical curved surfaces with distortion. In actual production, the rationality and advancement of mold design directly determine the quality, production efficiency and production cost of the produced parts. Similarly, the craftsmanship of product part design determines the feasibility of mold design, as well as mold design and The degree of difficulty of processing.
[0047] The invention uses inward bending Perform stress analysis of the stamping process plan for the shaped stamping parts, and innovatively design a stamping process method to improve the corner strength of the punch bottom of the bending die and increase the life of the die; through the innovative pre-bending process method and die design, pre-bending and combination The bending simulation calculation and feasibility analysis ensure the dimensional accuracy of the bending fillet of the parts, and innovate the pre-bending and combined bending stamping process methods and die design.
[0048] The above-mentioned embodiments are only preferred embodiments of the present invention and are not used to limit the scope of implementation of the present invention. Therefore, all equivalent changes made with the content of the claims of the present invention shall be included in the scope of the claims of the present invention. .
