CN114101477A

CN114101477A - Processing method of large-deformation flanging bending connecting plate

Info

Publication number: CN114101477A
Application number: CN202111394723.0A
Authority: CN
Inventors: 田孟良; 刘雪红; 解为刚; 丁清国; 李兵兵; 马腾; 熊健; 游晓君; 冷滨; 韩慧琴
Original assignee: AECC Guizhou Liyang Aviation Power Co Ltd
Current assignee: AECC Guizhou Liyang Aviation Power Co Ltd
Priority date: 2021-11-23
Filing date: 2021-11-23
Publication date: 2022-03-01
Anticipated expiration: 2041-11-23
Also published as: CN114101477B

Abstract

The invention discloses a processing method of a large-deformation folded-edge bending connecting plate, which adopts a polygonal plane plate, and finishes the bending of a first bending edge and the bending of a curved surface on the first bending edge in a primary stretching process by a stretching deformation method to form a folded-edge bending connecting plate semi-finished product; and then, a second bending edge and a third bending edge are bent at one time on the formed semi-finished product of the flanging bending connecting plate by adopting a bending method. According to the invention, aiming at the situation of wrinkles and cracks caused by bending deformation in double folding, the problem of part cracks caused by bending in common bending is solved at one time by improving the bending mode with the bending molded surface, the flat state of the bending surface is ensured, and a better positioning basis is provided for subsequent re-folding.

Description

Processing method of large-deformation flanging bending connecting plate

Technical Field

The invention belongs to the technical field of sheet metal forming, in particular to a method for forming a thin-wall sheet metal, which particularly realizes the bending forming of a three-fold surface forming structure with large bending deformation and solves the problem of cracks in a large-deformation bending method.

Background

The connecting plate (as shown in figure 1) is a stainless steel sheet metal forming part in an aircraft engine assembly and is mainly used for connecting three sections of the bottom surface, the skin and the front cover of a guide rail part, the surfaces of the connecting part are in different directions, so that the connecting plate is special in shape and is bent in different directions, and the three bent sides are respectively connected with the edge of a triangular-like plane base body (wall surface) to form a multi-bent-side plate sheet forming structure. The triangle-like shape (or called as special-shaped triangle) refers to a traditional triangle with two straight lines and one curved line in three edges of a plane substrate, and not three straight lines.

Three bending sides (a first bending side, a second bending side and a third bending side) in the connecting plate are vertical to a triangle-like plane substrate, wherein two bending sides at a straight side are in a plane state, the plate deformation at the bending sides belongs to a pure bending shape, the bending sides of a triangular bevel side (a curve side) not only have a straight surface (a plane), but also have secondary bending deformation at two ends of the straight surface (the plane) to form a curved surface, the whole profile deformation is in a multi-dimensional forming state, the deformation length is large, and the shape deformation at the bending sides is easy to generate the problem of tensile crack.

The traditional processing method is that a bending belt is bent for the second time, a flat plate with a certain shape is unfolded according to the shape of a part, the plate is placed on a section block with a bending surface, the plate is firstly bent into an arc edge shape under the pressing of two section blocks, then the two section blocks move together, and the side surface of the section block and the other wall surface are utilized to generate a bending edge shape; in this type of bending die for bending a bending strap (as shown in fig. 2), regardless of whether the bending die is bent while bending, or is bent after bending, the bending deformation pulls the material at the folded edge, which causes the joint between the bending arc R and the folded edge to tear, and the bending die cannot be bent into a desired shape.

In order to solve the technical bottleneck of processing a multi-folded part with a bent profile, a novel process method is required, the profile dimension requirement of the profile can be guaranteed, the circular arc and the folded edge are completely kept at the secondary bending part, cracks do not occur, and the design requirement of a product is completely met.

Disclosure of Invention

In order to solve the technical problems, the invention aims to provide a method for processing a large-deformation folded edge bending connecting plate, which is improved aiming at the method for processing a multi-folded edge part with a bending profile of the large-deformation folded edge bending connecting plate, particularly under the conditions of wrinkles and cracks caused by bending deformation in folding, the problem of part cracks caused by bending in common bending is solved at one time by improving the bending mode with the bending profile, the smooth state of a bending surface is ensured, and a better positioning basis is provided for subsequent re-folding.

In order to realize the purpose, the invention adopts the following technical scheme:

a processing method of a large-deformation folded-edge bending connecting plate comprises a triangular-like plane base body, three edges of the plane base body are respectively and vertically connected with a first bending edge, a second bending edge and a third bending edge, wherein the first bending edge comprises a curved surface, the second bending edge and the third bending edge are planes,

step one, adopting a polygonal plane plate, and completing bending of a first bending edge and bending of a curved surface on the first bending edge in a primary stretching process by a stretching deformation method to form a semi-finished product of a folded edge bending connecting plate;

and step two, bending a second bending edge and a third bending edge at one time on the semi-finished product of the folding bending connecting plate formed in the step one by adopting a bending method.

And in the third step, the flanged bent connecting plate formed in the second step is placed on a mould with the outline of the standard flanged bent connecting plate, the size of the mould surface is checked, the outline of the outer edge of the flanged bent connecting plate is drawn along the outer edge of the mould by using a scriber, and redundant edges are cut off by using a mechanical method.

Optionally, in the first step, the stretching die used for stretching and deforming the first bending edge includes a blank holder, and the blank holder is used for pressing the lower surface of the polygonal planar sheet material;

the upper die is a female die, and the inner wall of the female die is used as a first molding surface of the first bending edge;

the lower die is a male die, the outer wall of the male die is a second forming surface matched with the inner wall of the female die and used for the first bending edge, and when the male die is combined with the female die, a lateral gap is formed between the second forming surface of the male die and the first forming surface of the female die;

when the inner wall of the female die and the outer wall of the male die move in opposite directions, the polygonal plane plate is bent and deformed under the stretching action and enters the lateral gap, and finally, the curved surface bending and the edge folding deformation of the first bending edge are finished at one time under the action of the inner wall and the outer wall.

Alternatively, the drawing die further comprises a positioning pin arranged on the blank holder and used for being in close contact with the outline edge of the polygonal plane plate.

Alternatively, the female die and the male die are of a bilateral symmetry structure, and two flanged bent connecting plate semi-finished products are formed in the primary stretching deformation process of the stretching die.

Alternatively, in the second step, the bending die used for bending the second bending edge and the third bending edge comprises,

an upper platform and a lower platform;

the lower die frame is positioned on the lower platform;

the upper molded surface of the ejection block is used for pressing the lower surface of the plane part of the flanged bent connecting plate semi-finished product;

and the lower profile of the upper male die is used for pressing the upper surface of the planar part of the flanged bent connecting plate semi-finished product.

Furthermore, when the upper surface and the lower surface of the plane part of the folded bending connecting plate semi-finished product are respectively compressed by the upper male die and the ejection block, the upper platform and the lower platform move relatively to pull the folded bending connecting plate semi-finished product into a gap between the upper male die and the lower die frame from the surface of the lower die frame on the outer side, and the second bending edge and the third bending edge on the folded bending connecting plate semi-finished product are bent and formed by extruding the outer surface of the upper male die and the inner side surface of the lower die frame.

Alternatively, the lower die frame, the ejection block and the upper male die are of a bilateral symmetry structure, and the two flanged bent connecting plate semi-finished products are bent in the primary bending process.

Alternatively, the outline edge of the polygonal planar plate comprises a zigzag edge and a third straight line edge, the two ends of the zigzag edge are respectively a first straight line edge and a second straight line edge, the first straight line edge and the second straight line edge are parallel to each other, and the third straight line edge with a right-angle notch is opposite to the zigzag edge.

Compared with the original bending forming method, the forming method of the improved flanging bending connecting plate obviously improves the deformation capacity of the flanging plate with bending, converts bending deformation into tensile deformation, avoids unstable wrinkling of the wall surface caused by mutually pulling the plate by bending and flanging, avoids tearing at the joint caused by overlarge material deformation caused by large length of the bending surface, and effectively solves the wrinkling and tearing problems of the large-deformation bending flanging.

The bending and bending forming effect of the invention is verified by practice, the formed connecting plate part has flat shape, accurate bending size and clear profile, the processing of a plurality of parts is finished without scrapping, compared with the prior forming method that the parts are bent for a plurality of times and are pre-pressed by rubber sheets, and then the pressure test is repeated, and finally the qualification rate of the parts is still low, the invention proves the successful improvement of the invention and has the significance of innovation value and popularization and application.

Drawings

FIG. 1 is a perspective view of a large deformation hemmed curved web of the present invention;

FIG. 2 is a schematic view of a conventional bending die;

FIG. 3 is a sheet blank view of a part of the present invention;

FIG. 4 is a drawing of a drawing die of the present invention;

FIG. 5 is a schematic view of a semi-finished connecting plate of the present invention;

FIG. 6 is a schematic view of a secondary bending mold according to the present invention;

FIG. 7 is a top view of the lower mold frame, lower platen, and ejector block of FIG. 6;

FIG. 8 is a schematic view of a cutting pattern;

FIG. 9 is a schematic view of a lower platform;

FIG. 10 is a schematic view of an ejector block;

FIG. 11 is a schematic view of a lower mold frame;

FIG. 12 is a schematic view of an upper male mold;

in the drawing, 1, a lower template, 2, a blank holder, 3, a guide post, 4, a guide sleeve, 5, an upper template, 6, a male die, 7, a female die, 8, a positioning pin, 9, a mandril, 10, a flanging bending connecting plate semi-finished product, 11, a lower platform, 12, a lower die frame, 13, an ejection block, 14, an upper male die and 15, an upper platform are arranged.

Detailed Description

The present invention will be further described with reference to the accompanying drawings and specific embodiments, but it should not be understood that the scope of the subject matter of the present invention is limited to the following embodiments, and various modifications, substitutions and alterations made based on the common technical knowledge and conventional means in the art without departing from the technical idea of the present invention are included in the scope of the present invention.

The invention aims to meet the technical requirements of the structure of a product with bending and large deformation by changing the existing processing thought.

The processing method of the connecting plate with the bending large deformation generally adopts a twice forming mode, three folded edges are formed twice, firstly, a stretching structure with an edge pressing mode is adopted to realize the shape of the folded edge with the bending (a first bending edge), and then, a bending die with a pressing mode is adopted to finish the shape of the simple folded edge (a second bending edge and a third bending edge).

According to the shapes and the sizes of the bending circular arc and the wall surface of the large-deformation folded edge bending connecting plate, as shown in figure 3, the large-deformation folded edge bending connecting plate is unfolded into a nearly rectangular outer shape plane plate with a Z-shaped upper edge and a right-lower corner with a right-angle notch (the left side and the right side are two parallel straight edges), and the plate is cut into the shapes by adopting a mechanical cutting method.

Installing a drawing die between an upper template 5 and a lower template 1 of a hydraulic machine, installing an ejector rod 9 in an ejector rod hole in the lower template 1, and enabling the upper end of the ejector rod 9 to be tightly attached to the lower surface of the blank holder 2 after penetrating through the ejector rod hole; and starting the ejection function of the hydraulic press to eject the ejector rod 9 until the upper surface of the blank holder 2 is higher than the upper surface of the male die 6. The cut sheet is placed on a blank holder 2 of a die with a stretching structure and placed at a proper position (in the embodiment, the position of the sheet is limited by a plurality of positioning pins 8 on the blank holder 2), so that the bent part is overlapped on the surface of a male die 6 (namely, the edge profile of the male die 6 approximately corresponds to the intersection edge position of a first bending edge and a planar substrate), the sheet is accurately positioned under the lower surface of a female die 7 and the upper surface of the blank holder 2 in a pressing mode, the female die 7 moves downwards along with an upper die plate 5 of the device (the upper die plate 5 and the lower die plate 1 are connected and guided through a guide pillar 3 and a guide sleeve 4), the bent part of the sheet corresponding to the first bending edge is bent and deformed under the combined action of the inner wall of the female die 7 and the outer wall of the male die 6 and enters a gap between the female die 7 and the male die 6, and finally the bending and flanging deformation process is completed at one time under the action of the inner and outer walls of the die. In the embodiment, the female die 7 and the male die 6 are designed in a bilateral symmetry mode, so that the female die 7 and the male die 6 can be matched once to complete two flanged bent connecting plate semi-finished products 10.

The other two folding edges (the second folding edge and the third folding edge) of the connecting plate are formed by adopting a bending die which completes two pieces at one time to complete the deformation process on the basis of bending the folding connecting plate semi-finished product 10.

The above-mentioned half-finished product 10 of the bent and connected plate with the first bent edge is reliably positioned on the profile of the ejection block 13 of the bending die (as shown in fig. 10, the inner surface B of the ejection block 13 is used for attaching and positioning the first bent edge profile of the half-finished product of the bent and connected plate with the first bent edge, the upper surface a is used for attaching and positioning the triangle-like plane base body of the half-finished product of the bent and connected plate with the first bent edge), the upper surface (the upper surface a in fig. 10) of the ejection block 13 and the lower surface (fig. 12) of the upper punch 14 press the plane part (the triangle-like plane base body part in fig. 1) of the half-finished product of the bent and connected plate with the first bent edge, the ejection block 13 (fig. 10) is arranged inside the lower die frame 12 (fig. 11), the lower die frame 12 is arranged on the lower platform 11 (fig. 9), the lower platform 11 is also provided with a lifting rod for lifting the ejection block 13 upwards from the lower die frame 12, and the upper punch 14 moves downwards along with the upper platform 15, and (3) drawing the plate into a gap between the upper male die 14 and the lower die frame 12 from the surface of the lower die frame 12 on the outer side, and extruding the outer surface of the upper male die 14 and the inner side surface of the lower die frame 12 to realize the forming of the second bent edge and the third bent edge of the connecting plate at one time.

And (5) as shown in fig. 8, placing the bent part on a mould with the outline of the part, checking the size of the profile of the part, drawing the outline of the outer edge of the part along the outer edge of the mould by using a scriber, and cutting off the redundant edge of the part by using a mechanical method to finish the final processing of the part.

Referring to fig. 1 and 3-12, the device for processing the large-deformation folded-edge bending connecting plate comprises a set of stretching dies and a set of bending dies for the connecting plate, and the specific processing steps are as follows:

1. a flat plate material with the thickness of 1.2 is machined into a plane approximately rectangular plate with a Z-shaped upper edge (used for a first bending edge) and a right-angled notch (used for dividing a second bending edge and a third bending edge) at a lower right-lower edge by a mechanical cutting mode to serve as a blank material of a part (figure 3).

2. A drawing die (figure 4) for simultaneously bending and flanging for the first forming is installed on a platform of a hydraulic press, the platform hole is aligned with a top rod hole of a lower template 1, the lower template 1 is fixed on a lower platform of the hydraulic press, an upper template 5 is partially fixed on the upper platform by the same method, the upper template 5 and the lower template 1 are connected in a guiding mode through a guide post 3 and a guide sleeve 4, a female die 7 is connected onto the upper template 5, and a blank holder 2 and a male die 6 are connected onto the lower template 1.

3. And starting the hydraulic press, moving the upper platform upwards to drive the upper template 5 and the female die 7 to move upwards together, separating the female die 7 from the male die 6, and starting the ejector rod 9 device to jack the blank holder 2 to be flush with the upper surface of the male die 6.

4. The blank plate cut in the step 1 is placed at a proper position on the blank holder 2, the position is determined through the positioning pin 8, the upper platform of the hydraulic press is started to move downwards, the lower surfaces of the upper die plate 5 and the female die 7 and the upper surface of the blank holder 2 press the blank plate to move downwards together, the pressed part of the blank plate is not moved, the rest part of the blank plate is stretched along the inner walls of the male die 6 and the female die 7 under the joint extrusion of the outer wall (a second forming surface) of the male die 6 and the inner wall (a first forming surface) of the female die 7, the deformation of the bent shape is completed in the gap between the two, and the pressing part and the bending part form a folded edge in the downward moving process of the die, so that the technological requirements of completing bending and folding at one time are met.

5. After the first bending edge forming is completed, the female die 7 moves upwards until the female die is separated from the male die 6, the bending and flanging processes of the part are completed, and the flanging bending connecting plate semi-finished product 10 part is taken out (fig. 5).

6. Installing a secondary bending die (figures 6 and 7), installing an upper platform 15 and a lower platform 11 on hydraulic equipment, installing a lower die frame 12 on the lower platform 11, installing an ejection block 13 in the lower die frame 12, and ejecting the ejection block 13 in the lower die frame 12 by using an ejection rod to penetrate through the lower platform 11 until the top surface of the ejection block 13 exceeds the top surface of the lower die frame 12.

7. The prefabricated flanged bent connecting plate semi-finished product 10 is placed on a positioning profile in an ejector block 13 (as shown in fig. 10, an upper surface a of the ejector block 13 is used for a planar part of the flanged bent connecting plate semi-finished product 10, in particular a triangular-like planar base part, an inner surface B of the ejector block 13 is used for a first bending profile of the flanged bent connecting plate semi-finished product 10), and the rest plane is attached to the upper surface of the lower mold frame 12.

8. An upper male die 14 (figure 12) moves downwards under the drive of an upper platform 15, the protruding part of the upper male die 14 is gradually attached to an ejection block 13, the flanged bent connecting plate semi-finished product 10 is pressed onto the surface of the ejection block 13, the middle plane of the upper male die 14 presses the plane part of the flanged bent connecting plate semi-finished product 10 to be attached to the upper surface of the ejection block 13 along with the continuous downward movement of the upper male die 14, then the flanged bent connecting plate semi-finished product 10 moves downwards and enters a lower die frame 12, the two sides of the outer side of the flanged bent connecting plate semi-finished product 10 are bent and deformed under the action of the inner side wall of the lower die frame 12 and the outer side wall of the upper male die 14 and enter a gap formed by the side surfaces of the lower die frame 12 and the upper male die 14, and the bending deformation of a second bending side and a third bending side is completed until the whole surface enters the lower die frame 12.

9. And starting the upper platform 15 part, and when the upper male die 14 is lifted to be completely separated from the lower die frame 12, jacking the ejection block 13 by using a jacking rod until the part is exposed out of the lower die frame 12, and taking out the part with the allowance.

10. And (3) placing the part with the allowance on a cutting mould (figure 7), marking a cutting line on the edge surface of the part by using a scriber according to the outline edge of the mould, and mechanically cutting off the allowance outside the part according to the cutting line to complete the processing and delivery of the part.

Claims

1. The utility model provides a processing method of crooked connecting plate of big deformation hem, the crooked connecting plate of hem includes class triangular plane base member, on three edges of plane base member respectively perpendicular connection first limit of buckling, the limit of buckling of second and the limit of buckling of third, wherein, first limit of buckling contains the curved surface, and the limit of buckling of second and third is buckled the limit and is the plane, its characterized in that: the processing method comprises the following steps of,

2. The processing method of the large-deformation folded-edge bending connecting plate as claimed in claim 1, wherein the processing method comprises the following steps: and step three, in the step three, the folded edge bending connecting plate formed in the step two is placed on a mould with the outline of the standard folded edge bending connecting plate, the size of the molded surface is checked, the outline of the outer edge of the folded edge bending connecting plate is drawn along the outer edge of the mould by using a drawing needle, and redundant edges are cut off by adopting a mechanical method.

3. The processing method of the large-deformation folded-edge bending connecting plate as claimed in claim 1, wherein the processing method comprises the following steps: in the first step, the stretching die adopted when the first bending edge is stretched comprises,

the blank holder is used for pressing the lower surface of the polygonal plane plate;

4. The processing method of the large-deformation folded-edge bent connecting plate as claimed in claim 3, wherein the processing method comprises the following steps: the positioning pin is arranged on the blank holder and is used for being in close contact with the outline edge of the polygonal plane plate.

5. The processing method of the large-deformation folded-edge bent connecting plate as claimed in claim 3, wherein the processing method comprises the following steps: the female die and the male die are of bilateral symmetry structures, and two flanged bent connecting plate semi-finished products are formed in the primary stretching deformation process of the stretching die.

6. The processing method of the large-deformation folded-edge bending connecting plate as claimed in claim 1, wherein the processing method comprises the following steps: in the second step, the bending die adopted when bending the second bending edge and the third bending edge comprises,

an upper platform and a lower platform;

the lower die frame is positioned on the lower platform;

7. The processing method of the large-deformation folded-edge bent connecting plate as claimed in claim 6, wherein the processing method comprises the following steps: when the upper surface and the lower surface of the plane part of the folded bending connecting plate semi-finished product are respectively compressed by the upper male die and the ejection block, the upper platform and the lower platform move relatively, the folded bending connecting plate semi-finished product is pulled into a gap between the upper male die and the lower die frame from the surface of the lower die frame on the outer side, and the second bending edge and the third bending edge on the folded bending connecting plate semi-finished product are bent and formed by extruding the outer surface of the upper male die and the inner side surface of the lower die frame.

8. The processing method of the large-deformation folded-edge bent connecting plate as claimed in claim 6, wherein the processing method comprises the following steps: the lower die frame, the ejection block and the upper male die are of bilateral symmetry structures, and two flanged bent connecting plate semi-finished products are bent in the primary bending process.

9. The processing method of the large-deformation folded-edge bending connecting plate as claimed in claim 1, wherein the processing method comprises the following steps: the outline edge of the polygonal planar plate comprises a Z-shaped edge and a third straight line edge, the two ends of the Z-shaped edge are respectively a first straight line edge and a second straight line edge, the first straight line edge and the second straight line edge are parallel to each other, and the third straight line edge with a right-angle notch is opposite to the Z-shaped edge.