Method for manufacturing integral heavy-load bearing structure pull rod on the basis of volume forming

Abstract

The invention belongs to the technical field of heavy-load bearing structure manufacturing in multiple fields of aircrafts, ships, automobiles and the like, and discloses a method for manufacturing anintegral heavy-load bearing structure pull rod on the basis of volume forming. The method is characterized in that thickened ends are formed through model thickening and radial forging drawing-out; model rotary shrinkage is used, a rotary shrinkage tool performs feeding motion relative to a model, and a metal blank rotates along with the model or the rotary shrinkage tool rotates around the blankand the model through different rotary shrinkage temperatures, rotary shrinkage ratios and rotary shrinkage speeds; the blank is pressed and generates continuous local deformation, and a hollow rotational part is obtained; and local non-deformation annealing of a machined part is achieved, the coaxial concentricity is calibrated, and surface wrinkles are eliminated. The manufactured integral pullrod is unique in structure and excellent in performance, the product consistency is greatly improved, the service life of the integral pull rod is greatly prolonged compared with that of a traditional split type welding pull rod, and a good solution is provided for the anti-fatigue strengthening problem of the pull rod.

Description

technical field [0001] The invention belongs to the technical field of manufacturing heavy-duty load-bearing structures of aircraft, and in particular relates to a method for manufacturing integral heavy-duty load-bearing structure tie rods based on volume forming. Background technique [0002] At present, the closest existing technology: in the aircraft structure, many external structural parts, such as the engine nacelle, APU cabin, air-conditioning cabin, landing gear, etc., are connected to the aircraft body through braces, and these tie rods connect the external structure. The aerodynamic force, gravity and other loads received by the parts are transmitted to the body. The tie rod becomes the key main force-bearing part. Due to the weight reduction requirements of aircraft design, these tie rods are usually designed to be hollow while meeting the strength requirements. The traditional manufacturing technique is to weld joints at both ends of the steel pipe fitting pro...

AI Technical Summary

Problems solved by technology

[0005] (1) The coaxial concentricity of welded joints and pipe fittings cannot be guaranteed in traditional split manufacturing technology, and there is a certain additional bending stress when the tie rod is loaded, and the tie rod will bear excessive cyclic tensile stress and cause fatigue damage

[0006] (2) The extruded pipes of the traditional split manufacturing technology welded tie rods are of equal wall thickness, and the equal strength design method cannot be used to reduce weight

However, the heat treatment process cannot completely and effectively eliminate the internal stress, so it will also produce deformation induced by internal stress release, resulting in the inability to guarantee the coaxial concentricity

Moreover, the size of the tie rods in each part is different, and the calibration tooling needs to be customized, resulting in a significant increase in production costs and cycle time

The extruded pipes of the traditional split manufacturing technology welded tie rods are of equal wall thickness and cannot be reduced in weight by applying the equal strength design method

If you want to change the middle of the tie rod into a variable wall thickness, you need a special extrusion model or a cutting method to achieve it, and the production cost and cycle increase

Secondly, due to the uneven thermal expansion and heat conduction of variable wall thickness pipe fittings and joints during welding, it will also lead to increased welding deformation, which further increases the difficulty of coaxial concentricity calibration

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