Method for forming lobes of large-amplitude lobe mixer
阅读说明:本技术 一种大波幅波瓣混合器波瓣的成形方法 (Method for forming lobes of large-amplitude lobe mixer ) 是由 李新孝 申健 张东升 石佩珏 吴亚凤 贾军利 于 2020-06-30 设计创作,主要内容包括:本发明公开了一种大波幅波瓣混合器波瓣的成形方法,1.将板料切割成规定形状尺寸,沿其中心线弯曲,中心线与矩形连接边垂直,形成截面为U型的预制件;2.将U形预制件的槽口向外进行翻边;3.将板料前端沿垂直于中心线的方向压弯;4.切除工件的周边余量,得到波瓣,波瓣截面前半部分为矩形,后半部分为U型槽,截面与矩形连接边平行,槽深由波瓣前端至末端逐渐加深,U型槽两边存在向外的翻边。解决了成形过程中波瓣壁厚过度减薄和型面转接区剧烈褶皱的问题,能够成形出壁厚合格且型面圆滑的波瓣零件。(The invention discloses a method for forming lobes of a large-amplitude lobe mixer, which comprises the following steps of 1, cutting a plate into a specified shape and size, bending the plate along the central line of the plate, and enabling the central line to be vertical to a rectangular connecting edge to form a prefabricated part with a U-shaped section; 2. flanging the notch of the U-shaped prefabricated member outwards; 3. bending the front end of the plate material along a direction vertical to the central line; 4. and cutting peripheral allowance of the workpiece to obtain a lobe, wherein the front half part of the section of the lobe is a rectangle, the rear half part of the section of the lobe is a U-shaped groove, the section of the lobe is parallel to the connecting edge of the rectangle, the depth of the groove is gradually deepened from the front end to the tail end of the lobe, and outward flanges are arranged on two sides of the U-shaped groove. The problems of excessive reduction of the wall thickness of the lobe and severe wrinkles of the molded surface switching area in the forming process are solved, and the lobe part with qualified wall thickness and smooth molded surface can be formed.)
1. A method of shaping a large amplitude lobe mixer lobe comprising the steps of;
the method comprises the following steps that firstly, a plate is cut into a specified shape and size, the cut plate is divided into two parts, the front half part is a rectangle (2), the rear half part is a special-shaped polygon, one side edge of the rectangle (2) serves as a connecting edge and is connected with the special-shaped polygon, the front ends of two inclined edges (3) of the special-shaped polygon are connected with two corners of the connecting edge of the rectangle (2), the tail ends of the two inclined edges (3) are connected through a connecting section, and the connecting section is divided into three sections; the middle section (4) of the connecting section is parallel to the connecting edge of the rectangle (2) and is positioned in the middle of the two inclined edges (3), the relative distance between the connecting section and the connecting edge of the rectangle (2) is greater than the relative distance between the tail end of the inclined edge (3) and the connecting edge of the rectangle (2), and the two ends of the middle section (4) are linearly connected with the tail ends of the two inclined edges (3); bending the cut plate along the central line (5), wherein the central line (5) is vertical to the connecting edge of the rectangle (2) to form a prefabricated part with a U-shaped section;
step two, flanging the notch of the U-shaped prefabricated member outwards;
thirdly, bending the front end of the plate material along a direction vertical to the central line (5);
and step four, cutting off the peripheral allowance of the workpiece to obtain a lobe (1), wherein the front half part of the section of the lobe (1) is a rectangle, the rear half part of the section of the lobe (1) is a U-shaped groove, the section of the lobe is parallel to the connecting edge of the rectangle (2), the groove depth is gradually deepened from the front end to the tail end of the lobe (1), and outward flanges are arranged on two sides of the U-shaped groove.
2. The method of forming the large lobe mixer lobe of claim 1, where in step two the notches of the U-shaped preform are turned outward in steps of at least three turns.
3. The method of claim 1, wherein the lobe of the mixer with large lobes is formed such that after flanging the lobe (1) in the front half the flanging angle is 90 ° and the groove depth is zero.
4. The method for forming large-amplitude lobe mixer lobes according to claim 1, characterised in that in step one, the opposite sides of the connecting sides of the sheet front rectangle (2) are mirror images, and the sheet is arranged in mirror images to form an integral two-part sheet;
in the fourth step, the workpiece is divided into two parts along the mirror image edge, and the peripheral margins of the two parts of the workpiece are cut off to obtain two lobes (1).
5. Method for forming a large-amplitude lobe mixer lobe according to claim 4, characterised in that the rectangle (2) of the sheet material has a length of at least 20mm, the length direction being perpendicular to the connecting sides of the rectangle (2).
6. The method for forming the large-amplitude lobe mixer lobe of claim 1, wherein the edge of the maximum width of the sheet is chamfered, the chamfering direction is parallel to the exhaust direction of the lobe (1), and the end of the sheet after chamfering has a trimming margin of not less than 10 mm.
7. The method of forming a large lobe mixer lobe of claim 1 where the sheet stock retains a trim margin of no less than 10mm per side.
8. The method of shaping a large lobe mixer lobe of claim 1, where in step two, the flanging is performed using a flanging die.
9. The method of shaping a large lobe mixer lobe according to claim 1 where in step one the rectangle (2) of the sheet transitions with an arc of an inclined section.
10. The method of forming large lobe mixer lobes of claim 1 wherein in step three, a single punch press is used to press bend the sheet front end.
Technical Field
The invention belongs to the field of manufacturing of aero-engines, and relates to a method for forming lobes of a large-amplitude lobe mixer.
Background
The lobe mixer enables fan air of an outer culvert of the turbofan engine to be fully mixed with fuel gas of an inner culvert, noise of the engine can be reduced, thrust of the engine is increased, oil consumption rate is reduced, and infrared radiation of an exhaust system of the engine is restrained. The lobe mixer has the characteristics, and the fundamental reason is that the trailing edge of the fan-shaped lobe increases the initial shearing contact perimeter of the inner and outer culvert airflows, and simultaneously generates flow direction vortexes, orthogonal vortexes and horseshoe vortexes developing along the flow direction at the trailing edge of the lobe, and the vortexes greatly enhance the convection mixing effect of the inner and outer culvert airflows, so that the two airflows are fully mixed in a short distance.
The circular channel of the aircraft engine uses a circular arrangement of lobed mixers shaped like a chrysanthemum as shown in figure 1. The lobe mixer in the shape has good mixing characteristics, but the geometric profile of the lobe mixer is too complex, the structural rigidity is poorer than that of a common wave-free annular mixer, the mechanical manufacturing difficulty is high, the defects of folds and excessive wall thickness reduction are easily generated during lobe forming, and qualified lobes with qualified wall thickness and smooth profiles are difficult to obtain. The manufacturing process adopted by the lobe mixer is immature so far, the product quality is low, and therefore the difficulty in realizing engineering application is high.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a method for forming lobes of a large-amplitude lobe mixer, which solves the problems of excessive reduction of the wall thickness of the lobe and severe wrinkles of a molded surface transition area in the forming process and can form a lobe part with qualified wall thickness and smooth molded surface.
In order to achieve the purpose, the invention adopts the following technical scheme to realize the purpose:
a method for shaping a large-amplitude lobe mixer lobe comprises the following steps;
cutting a plate into a specified shape and size, wherein the cut plate is divided into two parts, the front half part is a rectangle, the rear half part is a special-shaped polygon, one side edge of the rectangle is used as a connecting edge and is connected with the special-shaped polygon, the front ends of two inclined edges of the special-shaped polygon are connected with two corners of the rectangular connecting edge, the tail ends of the two inclined edges are connected through a connecting section, and the connecting section is divided into three sections; the middle section of the connecting section is parallel to the rectangular connecting edge and is positioned in the middle of the two inclined edges, the relative distance between the connecting section and the rectangular connecting edge is greater than the relative distance between the tail end of the inclined edge and the rectangular connecting edge, and the two ends of the middle section are linearly connected with the tail ends of the two inclined edges; bending the cut plate along the central line of the plate, wherein the central line is vertical to the rectangular connecting edge to form a prefabricated part with a U-shaped section;
step two, flanging the notch of the U-shaped prefabricated member outwards;
thirdly, bending the front end of the plate material along a direction vertical to the central line;
and step four, cutting off the peripheral allowance of the workpiece to obtain a lobe, wherein the front half part of the section of the lobe is a rectangle, the rear half part of the section of the lobe is a U-shaped groove, the section of the lobe is parallel to the connecting edge of the rectangle, the groove depth is gradually deepened from the front end to the tail end of the lobe, and outward flanges are arranged on two sides of the U-shaped groove.
Preferably, in the second step, the notches of the U-shaped prefabricated member are turned outwards step by step, and the turning times are at least three times.
Preferably, after flanging, the flanging angle of the front half part of the lobe is 90 degrees, and the groove depth is zero.
Preferably, in the first step, the opposite edges of the rectangular connecting edges at the front ends of the plates are used as mirror images, and the plates are arranged in a mirror image mode to form an integrated two-part plate;
and in the fourth step, the workpiece is divided into two parts along the mirror image edge, and the peripheral margins of the two parts of the workpiece are cut off to obtain two lobes.
Further, the rectangular length of the plate is at least 20mm, and the length direction is perpendicular to the rectangular connecting edge.
Preferably, the edge of the maximum width position of the plate is trimmed, the trimming direction is parallel to the exhaust direction of the lobe, and trimming allowance not smaller than 10mm is reserved at the tail end of the plate after trimming.
Preferably, each edge of the plate remains a trimming margin of not less than 10 mm.
Preferably, in the second step, the flanging die is used for flanging.
Preferably, in the step one, the rectangular section and the inclined section of the plate are in arc transition.
Preferably, in the third step, one-time stamping is adopted, and the front end of the plate material is bent.
Compared with the prior art, the invention has the following beneficial effects:
according to the invention, the plate is bent into the U shape, so that the wall thickness can be kept uniform, and the problem that the bottom wall of the slot is excessively thinned when the lobe slot is too deep and is formed by other methods is solved; and then, the U-shaped part is turned over firstly and then bent, so that the bending thickness of the bending section is reduced, and the instability and wrinkling phenomena of the profile switching transition area in the bending process are avoided.
Furthermore, the U-shaped notch edge is turned over gradually for multiple times, so that the problems that the depth of the front section of the lobe is zero, and the deformation amplitude of the opening of the U-shaped notch wall is too large and instability and wrinkling are easy to occur due to one-time turning over are solved.
Furthermore, two lobes are symmetrically formed at one time through mirror image replication, the front ends of the two lobes are in butt joint, the compressive stress of the section in the process of bending the front section of the lobe is converted into tensile stress, and the wrinkling problem of the profile switching transition area in the forming process is thoroughly eliminated.
Drawings
Figure 1 is a schematic diagram of a lobe mixer arrangement of the present invention;
FIG. 2 is a schematic diagram of the lobe configuration of the present invention;
FIG. 3 is a schematic diagram of the sheet size design of the present invention;
FIG. 4 is a schematic diagram of a lobe cross-sectional profile of the present invention;
FIG. 5 is a schematic diagram of the U-lobe sizing of the present invention;
FIG. 6 is a schematic view of a triple turnup of the present invention;
FIG. 7 is a schematic structural diagram of the plate of the present invention;
FIG. 8 is a schematic view of the sheet of the present invention after bending;
FIG. 9 is a schematic view of a single turn-up of the present invention;
FIG. 10 is a schematic view of the double turnup of the present invention;
FIG. 11 is a schematic view of a triple turnup of the present invention;
FIG. 12 is a schematic view of the present invention after bending;
FIG. 13 is a schematic view of the post-mold trimming margin of the present invention.
Wherein: 1-lobe; 2-rectangle; 3-an inclined edge; 4-middle section; 5-the centre line.
Detailed Description
The invention is described in further detail below with reference to the accompanying drawings:
as shown in figure 1, the circular channel of the aircraft engine adopts a circular arrangement of lobe mixers, the appearance of the lobe mixer is similar to a chrysanthemum shape, and the lobe mixer with the shape has good mixing characteristics. The lobe mixer is manufactured by adopting a plate forming process because of large wave amplitude, complex profile and small wall thickness. The difference between the circumference of the front edge and the circumference of the tail edge of the lobe mixer is too large, so that the integral forming cannot be carried out, and only a
A
The manufacturing method of the
First, process design
1, sheet size design
To eliminate wrinkling and breakage defects, a fine calculation of the sheet size must be made.
1) Firstly, on a UG three-dimensional model of a
2) Then, from the front end, a plurality of cross sections perpendicular to a generatrix of the bottom of the
3) The length of each cross-sectional curve was measured.
4) Drawing an expansion diagram of the profile of the
5) The end of each section line in the developed view is connected, so that the shape profile of the plate can be obtained, and the developed view of the
6) According to the requirement of one-time forming of 2 pieces, a transition section between the 2 pieces is added at the front end.
7) In order to eliminate the phenomenon that the sharp corner at the tail end is extruded during flanging, the edge of the position with the maximum width of the plate is chamfered, the chamfering direction is parallel to the exhaust edge of the
8) The forming simulation can be carried out, and the profile of the sheet material is properly adjusted according to the simulation result. And the profile of the plate can be properly adjusted according to the actual deformation condition after the forming test.
2, designing
The plate can be flanged after being bent into a U shape. The
1) the profile of
2) The minimum inner envelope line of a plurality of projection curves is made on the projection surface, the maximum flanging width is referred, and the two ends of the envelope line are extended along the tangential direction of the groove wall, so that a longest cross section curve of the
3) The longest cross-sectional curve of a
4) And trimming each copied cross section curve to enable the length of each copied cross section curve to be equal to the length of a section line at the corresponding section of the plate.
5) And (3) connecting the ends of each trimmed U-shaped curve in series to obtain the edge profile of the opening end of the
3, flanging step number design
The intake section of
Second, manufacturing process
1, cutting and blanking
Two pieces are formed at a time. And (3) taking a plane passing through the front end and vertical to a generatrix at the bottom of the
The middle of the plate is a
2, bending U shape
The vertical plane perpendicular to the plate surface and passing through the generatrix of the bottom of the
3, the 1 st flanging
And when the edge is turned for the 1 st time, pressing materials from the bottom of the U-shaped groove, turning the edges of the two wings, and simultaneously precisely forming the molded surfaces on the two sides.
4, 2 nd turn-ups
Pressing the flanged tail end profile, performing local flaring and flanging on the region which is not formed in place, and finishing the 2 nd flaring and flanging, wherein the
5, 3 rd turn-ups
Pressing the flanged tail end profile, performing local flaring and flanging on the region which is not formed in place, and finishing the 3 rd flaring and flanging, wherein the
6, bending the small end
The small end profile is pressed and bent at one time along the vertical direction of the generatrix of the bottom of the
7, cutting off the edges
And cutting by adopting three-dimensional laser, and cutting off trimming allowance at the periphery of the
The above-mentioned contents are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modification made on the basis of the technical idea of the present invention falls within the protection scope of the claims of the present invention.
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