Titanium alloy cold extrusion joint

Abstract

The utility model discloses a titanium alloy cold extrusion joint which is of a cylindrical structure made of titanium alloy and comprises a rigid connector section, an extrusion section and a flexible connector section, a boss is arranged on the inner side of the extrusion section and is in transition connection with the inner side wall along a certain slope angle, and a first step-shaped convex ring is arranged on the outer side of the extrusion section. A step-shaped convex ring II is arranged on the outer side of the rigid interface section; a convex ring is arranged on the outer side of the flexible interface section; a groove is formed in the end face of the convex ring in the radial direction; and the outer diameter of the large-diameter section I is larger than that of the large-diameter section II and that of the convex ring. By providing high interference amount, the joint is tightly attached to the titanium alloy frame plate of the aircraft after generating plastic deformation, certain anti-push and anti-torsion performance is achieved while the sealing effect is achieved, beneficial hole circumferential pressure stress is provided for the titanium alloy frame plate under the cooperation of the high interference amount, the fatigue life of the titanium alloy frame plate of the aircraft is effectively prolonged, and the service life of the titanium alloy frame plate of the aircraft is prolonged. And connectors at two ends are connected with external conduits, so that long-life frame-penetrating connection is realized.

Description

TECHNICAL FIELD

[0001] The utility model relates to titanium alloy aircraft fuel system pipeline joint device technical field, specifically disclose a titanium alloy cold extrusion joint. BACKGROUND

[0002] The conduit assembly of the aircraft fuel system is generally connected through the frame by flange and connecting piece, the pressure of the aircraft fuel system is low, and the frame connecting piece is required not to leak when the pressure does not reach a certain value, and not to fall off when the push-out force and the unscrewing torque do not reach a certain value.

[0003] The working environment of the aircraft is harsh, and the working condition is complex, and a large number of satellite holes are manufactured at the frame plate part of the aircraft structure to realize bolt connection, which will seriously reduce the fatigue life of the aircraft body structure. With the large application of titanium and titanium alloy in advanced aircraft, serious potential corrosion will occur with the traditional aluminum alloy flange structure, reducing the service life and reliability of the aircraft. At the same time, the aluminum alloy or copper alloy frame joint cannot provide sufficient fatigue gain and enhance the fatigue life of the aircraft due to the large difference in strength between the material and the titanium metal body material, and cannot guarantee the sealing quality, leading to fuel system leakage, affecting flight safety, and has been prohibited from being used in advanced aircraft.

[0004] Therefore, how to avoid potential corrosion and improve the fatigue life of the frame position of the aircraft body under the premise of ensuring the sealing requirement is a key problem of aircraft assembly. INVENTION CONTENTS

[0005] The utility model aims at providing a titanium alloy cold extrusion joint which satisfies the long life, light weight and strong sealing of the titanium alloy aircraft frame part, overcomes the problems of low fatigue life, heavy weight and serious potential corrosion of the titanium alloy aircraft frame part, and guarantees the reliability and safety of the aircraft work.

[0006] The utility model technical solution: a titanium alloy cold extrusion joint is made of a cylindrical structure made of titanium alloy, including a rigid interface section, an extrusion section and a flexible interface section, a boss is arranged on the inner side of the extrusion section, the boss and the inner side wall are connected along a certain slope angle, a stepped convex ring one is arranged on the outer side of the extrusion section, the stepped convex ring one is a large diameter section one close to the rigid interface section, a stepped convex ring two is arranged on the outer side of the rigid interface section, the stepped convex ring two is a large diameter section two away from the extrusion section, a convex ring is arranged on the outer side of the flexible interface section, a groove is arranged on the end face of the convex ring in the radial direction, and the outer diameter of the large diameter section one is larger than that of the large diameter section two and the convex ring.

[0007] Further, the step-shaped convex ring has a thickness of 1-4 mm, which is a main force bearing structure part and bears axial force generated by material deformation during extrusion installation; the two ends of the joint part are external connecting piece interfaces, and the thickness can be determined according to the actual needs of various types of pipeline connecting pieces.

[0008] Further, the inner diameter of the boss is slightly smaller than the core rod for installation, but slightly larger than the inner diameter of the aircraft pipeline, so that interference installation is ensured while not affecting the internal flow resistance.

[0009] Further, the groove diameter and the small-diameter segment diameter of the step-shaped convex ring two are smaller than the small-diameter segment diameter of the step-shaped convex ring one and larger than the inner diameter of the boss, so that the titanium alloy cold extrusion joint 1 can be installed bidirectionally and freely while having sufficient structural strength.

[0010] Further, the boss and the chamfered position are coated with a solid dry film lubricant, the friction coefficient of the solid dry film lubricant is ≤0.05, and the temperature resistance can reach 300 DEG C, so that the effect of tensile force in the extrusion installation process of the joint is reduced.

[0011] Further, the extrusion section is in clearance fit with the titanium alloy aircraft frame plate when not installed.

[0012] The beneficial effects of the utility model are as follows:

[0013] (1) The fatigue strengthening effect is prominent, the titanium alloy cold extrusion joint and the frame plate part generate grain dislocation through high interference fit, residual compressive stress is introduced macroscopically, harmful tensile stress around the frame plate hole is eliminated, and the fatigue life around the hole is effectively improved.

[0014] (2) The installation efficiency is significantly improved, the titanium alloy cold extrusion joint is convenient and fast to install, a large number of bolt connections are not needed, the labor cost is low, the reliability is high, and the process control effect is good.

[0015] (3) The weight is greatly reduced, the titanium alloy cold extrusion joint is only composed of one part, a large number of bolt connections are not needed, the overall weight is greatly reduced compared with the flange-screw connection, and the weight reduction effect is prominent.

[0016] (4) The electrical conductivity is good, after extrusion installation, the cold extrusion joint is tightly attached to the aircraft frame plate, the contact area is large and is not affected by long-term use, can be considered as a whole with the frame plate, the electrical conductivity is high, and the electrical conductivity effect is good. BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments conforming to the present invention and, together with the description, serve to explain the principles of the present invention. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. In the drawings:

[0018] Figure 1 This is a schematic diagram of the structure of the titanium alloy cold extrusion joint provided by this utility model;

[0019] Figure 2 A perspective view of the titanium alloy cold-extruded joint provided by this utility model;

[0020] Figure 3 A schematic diagram of the structure of the titanium alloy cold extrusion joint provided by this utility model fixed on the titanium alloy frame plate of the aircraft.

[0021] Figure 4 Schematic diagrams of different connector structures for the titanium alloy cold extrusion joint provided by this utility model;

[0022] In the attached diagram: 1 - Titanium alloy cold extrusion joint

[0023] 11-Rigid interface section, 111-Protruding ring two, 1111-Large diameter section two

[0024] 12-Extrusion section, 121-Boss, 122-Protruding ring one, 1221-Large diameter section one

[0025] 13-Flexible interface segment, 131-Protruding ring, 1311-Groove

[0026] 2-Core rod, 3-Titanium alloy frame plate for aircraft, 4-Rigid connector, 5-Flexible connector

[0027] α-angle of slope. Detailed Implementation

[0028] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make the present invention more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art.

[0029] Please see Figures 1-2The figure shows a schematic diagram of the titanium alloy cold extrusion joint structure provided by this utility model. The cylindrical structure made of titanium alloy includes a rigid interface section 11, an extrusion section 12, and a flexible interface section 13. The inner side of the extrusion section 12 is provided with a boss 121, which is connected to the inner sidewall at a certain slope angle α. The outer side of the extrusion section 12 is provided with a stepped protruding ring 122. The stepped protruding ring 122 is closer to the rigid interface section 11 and is a large diameter section 1221. The outer side of the rigid interface section 11 is provided with a stepped protruding ring 111. The stepped protruding ring 111 is further away from the extrusion section 12 and is a large diameter section 1111. The outer side of the flexible interface section 13 is provided with a protruding ring 131. The end face of the protruding ring 131 is provided with a radial groove 1311. The outer diameter of the large diameter section 1221 is larger than the outer diameter of the large diameter section 1111 and the outer diameter of the protruding ring 131. The stepped protruding ring 122 has a thickness of 1-4mm and is the main load-bearing structural part, bearing the axial force generated by material deformation during extrusion installation. The two ends of the titanium alloy cold-extruded joint 1 are external connection interfaces, which can be determined according to the actual needs of various types of external pipeline connections. The inner diameter of the protrusion 121 is slightly smaller than that of the installation mandrel 2, but slightly larger than the inner diameter of the aircraft pipeline, thus ensuring interference installation without affecting internal flow resistance. When not installed, the extrusion section 12 has a clearance fit with the aircraft titanium alloy frame plate 3, with a high fit accuracy of H7 or higher, ensuring that the stress during extrusion installation is effectively transferred to the frame plate. The protrusion 121 and its slope angle α are coated with a solid dry film lubricant to reduce the tensile force required during joint extrusion installation. The solid dry film lubricant has a friction coefficient ≤0.05 and can withstand temperatures up to 300℃, thereby reducing the tensile force during joint extrusion installation. The diameter of the groove 1311 and the small diameter section of the stepped convex ring 111 are both smaller than the small diameter section of the stepped convex ring 122, but larger than the inner diameter of the boss 121. This ensures that the titanium alloy cold-extruded joint 1 can be freely installed in both directions while maintaining sufficient structural strength. A special coating or treatment can be added to the exterior of the titanium alloy cold-extruded joint 1 to give it certain special properties, such as adding adhesive to improve its sealing effect or adding surface treatment to improve its corrosion resistance.

[0030] Figure 3A schematic diagram illustrates the structure of a titanium alloy cold-extruded joint fixed to an aircraft titanium alloy frame plate. The titanium alloy cold-extruded joint 1 is placed inside the aircraft titanium alloy frame plate 3. High interference is provided by the interference fit between the boss 121 and the mandrel 2. Using an installation tool, the tapered mandrel 2 is pulled, causing radial expansion of the protective bushing. Through the extrusion section on the inner wall of the titanium alloy cold-extruded joint 1, the inner wall of the joint undergoes elastoplastic deformation. Elastic deformation occurs on the outer wall of the extrusion section and in the holes of the aircraft titanium alloy frame plate 3, generating deformation stress. The titanium alloy cold-extruded joint 1 is then fixed to the aircraft titanium alloy frame plate 3, ensuring a tight fit between the joint and the frame plate after plastic deformation, thus achieving a seal. Simultaneously, the high interference provides beneficial circumferential compressive stress to the frame plate, effectively improving its fatigue life.

[0031] Figure 4 The diagram shows the structure of the titanium alloy cold extrusion joint connected to different connectors. The titanium alloy cold extrusion joint 1 is fixed on the titanium alloy frame plate 3 of the aircraft. At the same time, one end is connected to the flexible connector 5 and the other end is connected to the rigid connector 4. Different connectors can be connected according to different working conditions.

[0032] The above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Any modifications or equivalent substitutions made by those skilled in the art to the technical solution of this utility model, as long as they do not depart from the spirit and scope of the technical solution of this utility model, are all covered within the scope of the claims of this utility model.

Claims

1. A titanium alloy cold-extruded joint, characterized in that: A cylindrical structure made of titanium alloy includes a rigid interface section (11), an extrusion section (12), and a flexible interface section (13). The extrusion section (12) has a boss (121) on its inner side, and the boss (121) is connected to the inner wall at a certain slope angle (α). The extrusion section (12) has a stepped protruding ring (122) on its outer side, and the stepped protruding ring (122) is close to the rigid interface section (11) and is the large diameter section (122). 1) The rigid interface section (11) is provided with a stepped protruding ring 2 (111) on the outside. The stepped protruding ring 2 (111) is a large diameter section 2 (1111) away from the extrusion section (12). The flexible interface section (13) is provided with a protruding ring (131) on the outside. The end face of the protruding ring (131) is provided with a groove (1311) in the radial direction. The outer diameter of the large diameter section 1 (1221) is larger than the outer diameter of the large diameter section 2 (1111) and the protruding ring (131).

2. The titanium alloy cold-extruded joint according to claim 1, characterized in that: The thickness of the stepped protruding ring (122) is 1-4 mm.

3. The titanium alloy cold-extruded joint according to claim 1, characterized in that: The inner diameter of the boss (121) is slightly smaller than that of the mounting mandrel (2), but slightly larger than that of the aircraft pipeline.

4. The titanium alloy cold-extruded joint according to claim 1, characterized in that: The diameter of the groove (1311) and the diameter of the small diameter section of the stepped convex ring II (111) are both smaller than the diameter of the small diameter section of the stepped convex ring I (122), and larger than the inner diameter of the boss (121).

5. The titanium alloy cold-extruded joint according to claim 1, characterized in that: When not installed, the extrusion section (12) is clearance-fitted with the titanium alloy aircraft frame plate (3).

6. The titanium alloy cold-extruded joint according to claim 1, characterized in that: The boss (121) and its bevel position are coated with a solid dry film lubricant.

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