CN108480481B

CN108480481B - Stretch forming method for airplane wingtip front edge skin

Info

Publication number: CN108480481B
Application number: CN201810340547.4A
Authority: CN
Inventors: 崔琳; 王伟; 韩艳彬
Original assignee: Xian Aircraft Industry Group Co Ltd
Current assignee: Xian Aircraft Industry Group Co Ltd
Priority date: 2018-04-16
Filing date: 2018-04-16
Publication date: 2023-06-23
Anticipated expiration: 2038-04-16
Also published as: CN108480481A

Abstract

A stretch forming method for the front edge skin of wing tip of airplane includes such steps as providing a pair of auxiliary dies with two eccentric T-shaped structures, fixing a pair of auxiliary dies to the jaws on two sides of stretching unit, clamping the plate for shaping part to the jaws on two sides of stretching unit, and pressing the plate to the root of shaping surface of shaping die by the front top plate of auxiliary die.

Description

Stretch forming method for airplane wingtip front edge skin

Technical Field

The invention relates to the technical field of aircraft part processing and manufacturing, in particular to a forming method for producing aircraft wingtip front edge skin parts by expanding the processing range of skin stretch forming equipment by an auxiliary die.

Background

The aircraft wing tip front edge skin has the main functions of reducing the induced resistance of the wing, improving the lift-drag ratio and dissipating wing tip vortex. The wing tip device has a certain influence on the structural characteristics while improving the aerodynamic performance of the aircraft, and particularly meets the technical requirements on the aspects of the flutter boundary characteristics, the structural weight characteristics, the structural rigidity, the elastic deformation of the wing and the like of the aircraft wing. These characteristics result in strict requirements on the shape and rigidity of such parts. The special shape of the wing tip front edge skin part with small opening, wide upper part and narrow lower part makes the processing manufacturability very poor, and conventional rolling, stretching, gate pressing and other technological methods and equipment cannot be used for final forming. Taking a wing tip skin of a certain model as an example, the production is carried out by adopting a rolling bending auxiliary and manual mainly process method at present, but the problems of insufficient rolling bending degree, difficult manual trimming and the like exist, the surface of a part has the quality defects of rugged, tool mark, slight distortion, out-of-tolerance appearance and the like, and the requirements of higher appearance and surface quality of the part are hardly met even if the part is formed.

Skin stretch forming is widely used for its excellent part forming quality, but stretch forming machines limit the range of workable parts due to their jaw characteristics, making it difficult to form such wingtip leading edge skin parts with existing equipment.

The novel process method is found to solve the problems that the front edge skin part of the wing tip of the airplane is difficult to form and the forming quality is poor, and is an urgent need for manufacturing the front edge skin part of the wing tip of the airplane with high quality and ensuring the safe flight of the airplane.

Disclosure of Invention

A method of stretch forming an aircraft wingtip leading edge skin, comprising: 1) The shaping mold comprises a base, a shaping surface and a connecting part of the shaping surface and the base, wherein the shaping surface is an irregular cone corresponding to the front edge skin of the wing tip of the airplane, the connecting part of the root of the shaping surface and the base is a wedge-shaped edge, the auxiliary mold is of two eccentric T-shaped structures which are bilaterally symmetrical, a horizontal front top plate and a vertical plate of the auxiliary mold are reinforced by a reinforcing rib, the edge of the front top plate is composed of a straight edge part and a bevel edge part, the included angle of the straight edge part and the bevel edge part corresponds to the shaping surface of the shaping mold, and the rear top plate is a step bulge matched with a jaw of stretching equipment; 2) And (3) relatively fixing a pair of auxiliary dies on jaws on two sides of the stretching equipment, clamping the sheet material for part forming at the jaws on two sides of the stretching equipment, and pressing the sheet material against the root of the forming surface of the forming die by the jaws through the front end top plate of the auxiliary dies during stretching forming, wherein the bevel edge part of the front end top plate of the auxiliary dies is matched with the wedge-shaped edge at the joint of the root of the forming surface and the base.

The beneficial effects of this application lie in: by using the auxiliary die, the narrowest processing width of the stretching machine tool is increased, meanwhile, the stretching force load is borne, the material flow of a stretching transition area of the part is guided, the side surface deformation of the part is restrained, the manufacturing difficulty of the wingtip front edge skin with a complex appearance is solved, the wingtip front edge skin part with excellent quality is produced, and meanwhile, a new thought is provided for manufacturing the part. The auxiliary die has ingenious conception, simple structure and convenient operation, and the forming method is very innovative.

The application is described in further detail below with reference to the accompanying drawings of embodiments:

drawings

FIG. 1 is a schematic view of an aircraft wingtip leading edge skin component structure;

FIG. 2 is a schematic view of an aircraft wingtip leading edge skin part forming mold structure;

FIG. 3 is a schematic view of an auxiliary mold structure for aircraft wingtip leading edge skin parts;

FIG. 4 is a schematic drawing of the principle of stretch forming of an aircraft wingtip leading edge skin component;

FIG. 5 is a schematic illustration of a method of stretch forming an aircraft wingtip leading edge skin component;

the numbering in the figures illustrates: 1 aircraft wing tip front edge skin part, 2 forming die, 3 forming surface, 4 base, 5 connecting part, 6 wedge edge, 7 auxiliary die, 8 front end top plate, 9 vertical plate, 10 reinforcing rib, 11 bevel edge part, 12 straight edge part, 13 rear end top plate, 14 jaw and 15 plate

Detailed Description

Referring to the drawings, the method for forming the aircraft wing tip front edge skin is provided, by means of a forming die 2 and an auxiliary die 7, the minimum distance between jaws 14 of a stretching machine tool is expanded, and the auxiliary die is inserted into the shape of a part during stretching forming to finish stretching forming of the part. The forming die 2 comprises a base 4, a forming surface 3 and a connecting part 5 of the forming surface and the base, as shown in fig. 2, the forming surface 2 is an irregular cone corresponding to the aircraft wing tip front edge skin part 1, a wedge-shaped edge 6 is arranged at the joint of the root of the forming surface and the base, the auxiliary die 7 is of two eccentric T-shaped structures which are symmetrical left and right, as shown in fig. 3, a reinforcing rib 10 is used for reinforcing between a horizontal front end top plate 8 and a vertical plate 9 of the auxiliary die 7, the edge of the front end top plate 8 is composed of a straight edge part 12 and a bevel edge part 11, the included angle between the straight edge part 12 and the bevel edge part 11 corresponds to the forming surface 3 of the forming die 2, and a step bulge matched with a jaw 14 of a stretching device is arranged on a rear end top plate 13.

Before the part is stretched, a pair of auxiliary dies 7 are relatively fixed on jaws 14 on two sides of stretching equipment, then a sheet material 15 for part forming is clamped at the jaws 14 on two sides of the stretching equipment, during stretching forming, the jaws 14 press the sheet material 15 to the root of a forming surface 3 of a forming die 2 through a front end top plate 8 of the auxiliary dies 7, the bevel edge part 11 of the front end top plate 8 of the auxiliary dies 7 is matched with a wedge-shaped edge 6 at the joint of the root of the forming surface 3 and a base, and the sheet material 15 can be guaranteed to be completely attached to the forming surface of the forming die, so that the part forming is completed.

The auxiliary dies are two bilaterally symmetrical and are in an eccentric T shape, four force transmission holes and six positioning holes are reserved on each auxiliary die, the auxiliary dies are fixed on the jaws by bolts, loads borne by the auxiliary dies are transferred to the jaws of the stretching equipment by pin rods, and each auxiliary die is provided with two reinforcing ribs for reinforcing the strength of the auxiliary dies.

Taking a certain type of skin stretch forming equipment as an example, the minimum distance between equipment jaws is 100mm, and the width of a stretchable part is necessarily narrow at the upper part and wide at the lower part, and the limit is the same width at the upper part and the lower part. After the auxiliary die is used, the minimum distance between jaws of the stretching equipment is expanded from 100mm to 610mm, so that small-opening parts with wide upper part and narrow lower part, such as wing tip front edge skins, can be stretched and formed.

Claims

1. A method of stretch forming an aircraft wingtip leading edge skin, comprising: the shaping die comprises a base, a shaping surface and a connecting part of the shaping surface and the base, wherein the shaping surface is an irregular cone corresponding to the front edge skin of the wing tip of the airplane, the junction of the root of the shaping surface and the base is a wedge-shaped edge, the pair of auxiliary dies are two eccentric T-shaped structures which are bilaterally symmetrical, a reinforcing rib is used for reinforcing the front end of a horizontal top plate and a vertical plate of each auxiliary die, the edge of the front end of the top plate is composed of a straight edge part and a bevel edge part, the included angle between the straight edge part and the bevel edge part corresponds to the shaping surface of the shaping die, and the rear end of the top plate is a step bulge matched with a jaw of a stretching device; the stretch forming method comprises the following steps: and (3) relatively fixing the pair of auxiliary dies on the jaws at two sides of the stretching equipment, clamping the sheet material for forming the front edge skin of the wing tip of the airplane at the jaws at two sides of the stretching equipment, and pressing the sheet material against the root of the forming surface of the forming die through the front end of the top plate of the auxiliary die when the jaws are used for stretch forming, wherein the bevel edge part of the front end of the top plate of the auxiliary die is matched with the wedge-shaped edge at the joint of the root of the forming surface and the base.

2. A method of stretch-forming an aircraft wingtip leading edge skin in accordance with claim 1 wherein the straight edge portion and the beveled edge portion of the leading edge of the roof have an arcuate outer edge.