A Spindle Head Mechanism of In-situ Backfill Friction Stir Spot Welding

Abstract

The invention discloses an in-situ backfilling type friction stirring spot welding main shaft head mechanism. The in-situ backfilling type friction stirring spot welding main shaft head mechanism is composed of two parts, one part includes a body structure hollow main shaft sleeve, and the other part includes an upper fixing shaft sleeve and an outer layer lower fixing sleeve, wherein the body structure hollow main shaft sleeve is connected with a machine tool rotation power main shaft and can rotate at a high speed, and the upper fixing shaft sleeve and the outer layer lower fixing sleeve are connected with the machine tool main shaft fixing part. The two parts (inner rotation and outer fixation) are integrated together to form the main shaft head mechanism through four pairs of angular bearings and other components. The main shaft head mechanism is an independent mechanical movement mechanism, and the whole technology process of in-situ backfilling friction spot welding (RFSSW) can be achieved. The in-situ backfilling type friction stirring spot welding main shaft head mechanism is simple in structure and easy to maintain, a stirring tool of the in-situ backfilling type friction stirring spot welding main shaft head mechanism can be conveniently dismounted, replaced and mounted. The main shaft head mechanism and a plain milling machine power main shaft are combined, the whole technology process of RFSSW can be achieved, accordingly, the manufacturing cost of RFSSW equipment is effectively reduced, and an important basis is provided for wide application and popularization of the RFSSW technology.

Description

technical field [0001] The invention belongs to the technical field of solid-phase friction welding, and in particular relates to a spindle head mechanism for realizing an in-situ backfilling friction stir spot welding process. Background technique [0002] In-situ refill friction stir spot welding (Refill Friction Stir Spot Welding-RFSSW) is an innovative solid phase friction spot welding technology developed by the German GKSS Research Center in 1999. After using this method for aluminum alloy spot welding, the surface of the weld seam is smooth, and there is no concave hole in the center of the welding spot, and the appearance of the spot weld seam is similar to that of the traditional resistance spot weld seam. Therefore, it has broad application prospects in the field of lightweight aluminum alloy structure manufacturing, such as aviation, aerospace and automobile industry. [0003] The principle of RFSSW process is shown in Figure 1(a), Figure 1(b), Figure 1(c) and Fi...

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Problems solved by technology

[0007] However, there are still the following main problems in RFSSW technology in industrial promotion and application: 1) Compared with traditional resistance spot welding equipment, RFSSW equipment obviously has high investment costs, which seriously hinders its popularization and application

The core of the RFSSW process is the friction stir spot welding tool and the spindle head mechanism, which requires the precise control of multiple servo motors to realize the process principle of in-situ backfilling, which makes the spindle head mechanism and control process of the equipment very complicated, coupled with the limitation of patented technology The manufacturing cost of RFSSW equipment is obviously high; 2), the uneven heating of the stirring tool is easy to produce spot welding ring defects

Since the tightening ring of the stirring tool is stationary, while the intermediate sleeve and the stirring pin rotate at high speed and frictionally heat the workpiece, obvious heating unevenness occurs on the contact surface between the tightening ring and the intermediate sleeve and the workpiece. When the intermediate sleeve moves up and down, it will be welded Insufficient plastic flow occurs around the nuclei, resulting in the formation of annular defects around the nugget, which will have a serious impact on the mechanical properties of friction spot welded joints

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