Application of laser welding in composite gears of automobiles

In the design and production of automotive transmission gears, in order to better reduce the difficulty of gear cold processing and hot processing and improve production efficiency, the gear is often divided into two independent parts for processing, and then the two parts are combined to form an integral composite gear, also known as a gear assembly, such as a gear assembly composed of a gear and a cone (engagement tooth).

The connection of composite gears mainly includes spline connection and beam welding connection. Spline connection is connected by internal and external splines. Its empty knife groove is large, the axial size of the gear is large, and the production efficiency is low: beam welding is mainly electron beam welding and laser welding. It replaces the spline connection with a smooth cylindrical matching connection form, reduces the empty knife groove, reduces the gear volume, reduces the weight of the vehicle, and significantly improves production efficiency. Among them, the transmission gear laser welding technology has developed rapidly and is also an important technology for laser processing.

Using laser welding technology to connect gear components can improve the product accuracy of transmission gears, simplify product structure and manufacturing process, facilitate the continuous adjustment of component structure and sample production in product development and trial production, and help designers to rationally layout product structure and continuously improve product development and production level: At the same time, due to the compact structure, improved accuracy and reliability of laser welding gears can reduce vehicle failure rate, improve vehicle operation flexibility and improve product reputation. This technology has high production efficiency and good application effect.

Principles and characteristics of gear laser welding.

1.1 Principle.

The laser beam of a certain pattern output by the laser is reflected in the light guide system and focused on each lens, becoming a beam with extremely high power density, which irradiates the gear welding part, and the metal in the small area of the welding circumference is quickly heated and melted for welding. In this process, the gear rotates around the rotation axis under the drive of the rotary table of the laser processing machine, forming a closed circular weld at the welding part.

1.2 Features.

Laser weldingUses a high-energy-density laser beam, and its welding depth is large. Laser welding is generally deep-melting welding; laser welding uses non-contact welding, with fast welding speed, small weld heat-affected zone, small deformation of welded gears, less post-welding processing, or even no processing required; high welding strength, welds generally have mechanical properties equivalent to or better than the parent material, allowing gears to transmit greater torque; high welding accuracy, no need for welding wire during welding; laser welding gears do not require a vacuum chamber, the welding environment is natural and intuitive, and no X-rays are generated.