Use tool of drawing die and expanded use method of use tool

Abstract

The invention discloses a using tool of a drawing die and an expanded using method of the drawing die, the tool comprises a female die, the bottom of the female die is provided with a groove for drawing forming, and the edge of the groove is provided with a female die chamfer; the top of the male die is provided with a protrusion matched with the groove for drawing forming, the outer edge of the protrusion is provided with a male die chamfer, and a fit clearance is formed between the inner peripheral side of the groove and the outer peripheral side of the protrusion; the blank holder is arranged on the outer side of the male die, blank holder force of the blank holder is provided by the ejector rod, a to-be-drawn sheet metal part is positioned between the blank holder and the female die, and by adjusting the blank holder force, the chamfer radius of the female die and the male die of the drawing die and the gap between the female die and the male die, expanded use of the drawing die is achieved, and the problems of cracks, scratches and the like of drawn parts are avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanical processing of aviation parts, and in particular relates to a tooling for using a sheet metal drawing die and a method for expanding the use of the tooling. Background Art

[0002] During the drawing process, helicopter sheet metal parts often have transverse cracks, accompanied by defects such as scratches on the inside, resulting in a high scrap rate, which increases production costs. For complex sheet metal parts, the forming quality cannot be guaranteed and the problem of drawing cracks cannot be avoided. Sheet metal parts generally use 2024 aluminum alloy, which has high strength and low elongation, and is not conducive to drawing forming. It has extremely high requirements for drawing tooling and drawing processes.

[0003] Therefore, how to provide a drawing die tooling and a new drawing die process that can control cracks in sheet metal parts is an urgent problem that technical personnel in this field need to solve. Summary of the invention

[0004] In view of this, the present invention provides a tooling for using a drawing die and a method for expanding its use, so as to change defects such as cracks and scratches that occur during the drawing process of existing helicopter sheet metal parts and improve the yield rate.

[0005] In order to achieve the above object, the present invention adopts the following technical solution: a tooling for a drawing die, comprising:

[0006] A female mold, wherein the bottom of the female mold is provided with a groove for drawing, and the inner edge of the groove is provided with a female mold chamfer;

[0007] A male mold, wherein a protrusion formed by drawing and matching the groove is provided on the top of the male mold, a male mold chamfer is provided on the outer edge of the protrusion, and a matching gap is provided between the inner peripheral side of the groove and the outer peripheral side of the protrusion;

[0008] A blank holder ring is arranged on the outer side of the male die and a push rod is used to provide the blank holder force of the blank holder ring. The sheet metal part to be drawn is positioned between the blank holder ring and the female die.

[0009] The beneficial effects of the present invention are: the sheet metal parts are drawn by the cooperation of the female mold and the male mold, the blank holder provides the blank holder force of the sheet metal parts, the size of the blank holder force directly affects the drawing effect of the sheet metal parts, and controls the matching clearance between the female mold and the male mold. The matching clearance also has a great influence on the drawing process. If the matching clearance is too small, the resistance will increase, and even thinning and drawing will occur; if the matching clearance is too large, the diameter size of the part is not easy to guarantee, and the female mold chamfer and the male mold chamfer are controlled. Too small a chamfer radius will increase the stress of the material, causing the dangerous section material to be greatly thinned and even broken. However, too large a chamfer radius will cause wrinkles to occur after the sheet metal parts are drawn, and the forming quality is poor. At the same time, the chamfer radius of the male and female molds should also consider the requirements of product design.

[0010] Preferably, the female die or the male die is controlled by an external press, and the blank holding force of the blank holding ring on the sheet metal part to be drawn is 15t to 18t.

[0011] Preferably, the female mold chamfer is a rounded corner, the male mold chamfer is a rounded corner, the fillet radius corresponding to the male mold chamfer is the arc edge size of the finished part, and the fillet radius corresponding to the female mold chamfer is larger than the fillet radius corresponding to the male mold chamfer.

[0012] Preferably, the fitting clearance is 3.250 +0.1 mm.

[0013] The present invention also discloses a method for enlarging and using a sheet metal drawing die, which comprises the following steps:

[0014] Step 1: According to the process requirements of the sheet metal parts, adjust the structural dimensions of the female and male molds. The chamfer size of the male mold is adapted to the arc edge size of the part, and the chamfer size of the female mold is adjusted according to the formula R 阴 = (5-8) δ is adjusted to 12.5 mm-20 mm, where δ is the minimum section thickness for drawing, and the minimum section thickness δ is calculated as 2.5;

[0015] Step 2: Adjust the clearance between the male and female molds. The clearance is the difference between the lateral dimensions of the female and male molds. Change the lateral dimension tolerance of the female mold so that the clearance is adjusted to 3.250. +0.1 mm;

[0016] Step 3: Adjust the blank holding force, use the ejector rod to provide the blank holding force to the blank holding ring, the blank holding force calculation formula is Q = F q, where F is the blank area of ​​the sheet metal part in the blank holding ring, q is the unit pressure value, and adjust the blank holding force to 15t to fix the sheet metal part to be drawn;

[0017] Step 4: The female mold and the male mold are closed under the control of an external press for a certain period of time and then demolded to form the product.

[0018] The beneficial effect of the present invention is that compared with the traditional sheet metal drawing forming process, the present invention achieves the expanded use of the drawing die by adjusting the blank holding force, the chamfer radius of the male and female dies of the drawing die, and the matching gap between the male and female dies, and will not cause cracks, scratches and the like on the sheet metal, thereby improving product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is an overall structural diagram of a tooling for a drawing die of the present invention;

[0020] Figure 2 A structural diagram of a male die of a tooling for a drawing die of the present invention;

[0021] Figure 3 A diagram showing the structure of a female mold of a tooling for a drawing die according to the present invention;

[0022] Figure 4 This is a schematic diagram of a sheet metal part using a tooling for a drawing die of the present invention.

[0023] 1 female mold, 2 groove, 3 female mold chamfer, 4 male mold, 5 protrusion, 6 male mold chamfer, 7 pressure ring, 8 ejector pin, 9 sheet metal part. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] See the attached Figures 1 to 4 According to an embodiment of the present invention, a tooling for using a drawing die includes:

[0026] A female mold 1, the bottom of the female mold 1 is provided with a draw-molded groove 2, and the edge of the groove 2 is provided with an arc-shaped female mold chamfer 3;

[0027] A male mold 4, the top of which is provided with a protrusion 5 formed by drawing to match the groove 2, an outer edge of the protrusion 5 is provided with an arc-shaped male mold chamfer 6, and a matching gap is provided between the inner peripheral side of the groove 2 and the outer peripheral side of the protrusion 5;

[0028] The blank holder 7 is arranged on the outside of the male mold 4 and the blank holder force is provided by the push rod 8. The blank holder will not affect the closing and drawing process of the male and female molds. The sheet metal part 9 to be drawn is positioned between the blank holder 7 and the female mold 1.

[0029] In other embodiments, the female die 1 or the male die 4 is controlled by an external press, and the blank holding force of the blank holding ring 7 on the sheet metal part 9 to be drawn is 15t to 18t.

[0030] In other specific embodiments, the female mold chamfer 3 is rounded, and the corresponding fillet radius of the female mold chamfer 3 is 12.5 mm; the male mold chamfer 6 is rounded, and the corresponding fillet radius of the male mold chamfer 6 is 4 mm, which is the arc edge size of the finished part.

[0031] In other embodiments, the clearance is 3.250 +0.1 Considering that the sheet metal has transverse cracks and scratches on the inside and outside during drawing, the gap between the male and female dies is adjusted from the original gap value Δ=3 to Δ=3.25.

[0032] The present invention also discloses a method for expanding the use of a tooling for a drawing die, which comprises the following steps:

[0033] Step 1: According to the process requirements of the sheet metal parts, adjust the structural dimensions of the female and male molds. The chamfer size of the male mold is adapted to the arc edge size of the part, and the chamfer size of the female mold is adjusted according to the formula R 阴 = (5-8) δ is adjusted to 12.5 mm-20 mm, where δ is the minimum section thickness for drawing;

[0034] Step 2: Adjust the clearance between the male and female molds. The clearance is the difference between the lateral dimensions of the female and male molds. Change the lateral dimension tolerance of the female mold so that the clearance is adjusted to 3.250. +0.1 mm;

[0035] Step 3: Adjust the blank holding force, use the ejector rod to provide the blank holding force to the blank holding ring, the blank holding force calculation formula is Q = F q, where F is the blank area of ​​the sheet metal part in the blank holding ring, q is the unit pressure value, and adjust the blank holding force to 15t to fix the sheet metal part to be drawn;

[0036] Step 4: The female mold and the male mold are closed under the control of an external press for a certain period of time and then demolded to form the product.

[0037] In specific implementation: the blank holder force is adjusted from 30t to 15t; the blank holder force of 15t refers to Table 4-21 of "Cold Punching Die Design", and the chamfer radius of the male die of the drawing die is the part size R 阳 =4.0mm, the female mold chamfer radius was originally R5, according to R 阴 = (5~8)δ, where δ is the minimum section thickness for drawing. Considering the subsequent sheet metal shaping requirements, R 阴 Increase to R10±2.

[0038] Taking into account that the sheet metal has transverse cracks and scratches on the inside and outside during drawing, the matching clearance between the male and female dies is adjusted from the original clearance value Δ=3 to Δ=3.25.

[0039] When forming a specific sheet metal part, the drawing process implementation plan is determined first. According to the size of sheet metal part 9, the drawing coefficient m=d / D=322 / 503>0.45~0.48 (the minimum allowable drawing coefficient for flanged parts is 0.45~0.48 when drawn once), and the deformation degree of the sheet metal part is not too large. Blank holding force Q=F·q=π / 4·(503 2 -322 2 )×0.1=11720Kg, where F is the blank area in the blank holder; q is the unit pressure value of 0.1Kg / mm 2 After calculation, the original blank holding force of 30T needs to be adjusted to 15T.

[0040] Improvements to the drawing die: During drawing, the edge is held by the ejector pin 8 and the blank holder 7. The radius of the female die chamfer 3 and the radius of the male die chamfer 6 have a great influence on the drawing process. Too small a chamfer radius will increase the stress of the material, causing the dangerous section material to become thinner and even break. However, for sheet metal parts such as cylindrical shells, wrinkles will occur when the outer circle of the rough material leaves the flat part of the blank holder 7, while for sheet metal parts 9 with bosses, wrinkles will not occur because they have not left the blank holder 7 at the end of drawing. At the same time, the chamfer radius of the male and female dies should also take into account the requirements of product design.

[0041] The chamfer radius of the drawing die male die is the part size R 阳 =4.0mm. The female mold chamfer radius was originally R5. 阴 = (5~8)δ calculation, considering the subsequent sheet metal shaping requirements, R 阴 Increase to R12.5.

[0042] The gap between the female die 1 and the male die 4 also has a great influence on the drawing process. If the gap is too small, the resistance will increase, and even thinning and drawing will occur; if the gap is too large, the diameter size of the part is difficult to guarantee.

[0043] During the drawing process of the sheet metal, there are transverse cracks and scratches on the inside and outside. It is necessary to adjust the gap between the female mold 1 and the male mold 4. The gap between the female mold and the male mold is the difference in the transverse dimensions of the male and female molds. The gap between the male and female molds is adjusted from the original single-side gap value Δ = 30 + 0.1 mm increased to Δ=3.250 +0.1 mm means changing the lateral dimension tolerance of the female mold.

[0044] Through the above-mentioned improvement of the drawing die process, the quality of the sheet metal parts during the drawing process is guaranteed, and problems such as cracks and scratches will not occur.

[0045] As for the device and the method of use disclosed in the embodiment, since they correspond to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the description of the method part.

[0046] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A tooling for a drawing die, characterized in that: include: A female mold (1), wherein a draw-molded groove (2) is provided at the bottom of the female mold (1), and a female mold chamfer (3) is provided at the inner edge of the groove (2); A male mold (4), wherein a protrusion (5) is provided on the top of the male mold (4) and is formed by drawing to match the groove (2), a male mold chamfer (6) is provided on the outer edge of the protrusion (5), and a matching gap is provided between the inner peripheral side of the groove (2) and the outer peripheral side of the protrusion (5); A blank holder ring (7) is arranged on the outer side of the male die (4) and a push rod (8) provides the blank holder ring with a blank holder force. A sheet metal part (9) to be drawn is positioned between the blank holder ring (7) and the female die (1).

2. The tooling for use of a drawing die according to claim 1, characterized in that: The female die (1) or the male die (4) is controlled by an external press, and the blank holding force of the blank holding ring (7) on the sheet metal part (9) to be drawn is 15t to 18t.

3. The tooling for use of a drawing die according to claim 1, characterized in that: The female mold chamfer (3) is a rounded corner, the male mold chamfer (6) is a rounded corner, the fillet radius corresponding to the male mold chamfer (6) is the arc edge size of the finished part, and the fillet radius corresponding to the female mold chamfer (3) is greater than the fillet radius corresponding to the male mold chamfer.

4. The tooling for use of a drawing die according to claim 1, characterized in that: The fit clearance is 3.250 +0.1 mm.

5. A method for expanding the use of a tooling for a drawing die according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1: According to the process requirements of the sheet metal parts, adjust the structural dimensions of the female and male molds. The chamfer size of the male mold is adapted to the arc edge size of the part, and the chamfer size of the female mold is adjusted according to the formula R 阴 = (5-8) δ is adjusted to 12.5 mm-20 mm, where δ is the minimum cross-sectional thickness for drawing, and the minimum cross-sectional thickness δ is 2.5 mm; Step 2: Adjust the clearance between the male and female molds. The clearance is the difference between the lateral dimensions of the female and male molds. Change the lateral dimension tolerance of the female mold so that the clearance is adjusted to Step 3: Adjust the blank holding force, use the ejector rod to provide the blank holding force to the blank holding ring, the blank holding force calculation formula is Q = F q, where F is the blank area of ​​the sheet metal part in the blank holding ring, q is the unit pressure value, and adjust the blank holding force to 15t to fix the sheet metal part to be drawn; Step 4: The female mold and the male mold are closed under the control of an external press for a certain period of time and then demolded to form the product.

Images