Manufacturing method of hollow valve

Abstract

The invention discloses a manufacturing method of a hollow air valve and belongs to air valves of engines. The manufacturing method of the hollow air valve comprises the following steps that (1) austenite rod materials and martensite rod materials are fed after heat treatment, after friction butt welding is conducted on the two rod materials, flash is removed, and then annealing treatment is conducted; (2) the rod materials are polished, wherein the outer circles of the rod materials are machined through a centerless grinding machine; (3) a bending experiment is conducted; (4) electric heading formation is conducted; (5) shot blasting is conducted; (6) cutting off is conducted; (7) the outer circle of a rod portions is polished; (8) hole drilling is conducted, wherein a hole is drilled at the center of the large end face of an air valve blank; (9) cleaning and drying are conducted, wherein the cavity formed through hole drilling and dried; (10) sodium feeding and filling are conducted; (11) disk end face overlaying is conducted. The manufacturing method of the hollow air valve solves the technical problem that since the contact area between the small-end face of hollow air valve austenite and solid austenite is small, after friction welding, the welding strength is low and avoids the potential risk that the rod portion of the hollow air valve is broken. Meanwhile, the problem that the coaxiality is out of tolerance, the wall thickness is not even is solved, and the reliability of the product is improved.

Description

technical field [0001] The invention relates to an engine valve, in particular to a method for manufacturing a hollow valve. Background technique [0002] The engine is the heart of the entire car, the valve is the valve in the heart, and the hollow valve is a high-end product in the valve. With the continuous emergence of high-speed and high-load engines and the continuous tightening of global carbon dioxide (CO2) emission regulations, the hollow valve advantage is becoming more and more obvious. The advantage of the hollow valve is that it can cool down and reduce weight in the engine, and fill the cavity with 50-60% volume of sodium metal, which melts at 97.5°C and has a specific gravity of 0.97g / cm3. Liquid sodium As the engine rotates, it moves accordingly, transferring heat from the valve head to the valve stem. Then the heat is transmitted through the valve guide, which plays a role in cooling, and the temperature drop can reach 100°C. When designing the engine, th...

AI Technical Summary

Problems solved by technology

[0004] The technical task of the present invention is to provide a method of manufacturing a hollow valve for the above-mentioned deficiencies in the prior art. The technical difficulty of low welding strength after welding; avoiding the potential risk of hollow valve stem fracture

At the same time, it also solves the problem of uneven wall thickness due to excessive coaxiality and improves product reliability.

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