Manufacturing process of solid cold-spun forged steel piston with internal cooling oil chamber

Abstract

The invention discloses a manufacturing process of a solid cold-spun forged steel piston with an internal cooling oil chamber. The manufacturing process comprises the following steps: performing solid forging to obtain a piston blank; machining a semi-finished piston product with an inside part of the internal cooling oil chamber and a shielding part for blocking off the internal cooling oil chamber; then heating the shielding part, and spinning downwards the shielding part of the internal cooling oil chamber of the piston by adopting the hot spinning process so that the shielding part contacts with the inside part of the internal cooling oil chamber so as to form the complete internal cooling oil chamber; and reserving the gap between the inside part and the shielding part of the internal cooling oil chamber and the shielding part without disposal or simply closing the gap by argon-arc welding and other common welding processes, and then performing precision machining to finally obtain the finished piston. The manufacturing process has the advantages of simple structure, more simple and convenient manufacturing procedures, high production efficiency, low manufacturing cost and the like, and can meet the requirements of an engine on high power, high strength and low emission.

Description

technical field [0001] The invention relates to a manufacturing process of a piston, in particular to a manufacturing process of a cold spinning forged steel integral piston with an inner cooling oil cavity. Background technique [0002] At present, high-performance diesel engines used in trucks, construction machinery, railway locomotives, and ships require high power, low fuel consumption, low noise, and low emissions, and their strengthening degree is increasing day by day. At present, the explosion pressure of domestically developed automotive diesel engines has exceeded 20MPa, and the traditional cast aluminum pistons have been difficult to meet the reliability requirements of high-performance diesel engines. For high-power, high-load diesel engine pistons, articulated structure pistons and forged steel pistons have emerged as the times require. [0003] Piston with hinged pendulum structure, that is, the piston head and piston skirt are manufactured separately and con...

AI Technical Summary

Problems solved by technology

But its manufacturing process is complex, the manufacturing cost is high, and the structural strength of the piston needs to be improved

[0006] Chinese patent CN2851607Y discloses another method for manufacturing forged steel pistons. In this method, the head and the skirt are forged separately, and the inner cooling oil cavity is formed by friction welding after the head and the skirt are separately processed. The friction welding is affected by the process. Due to the limited performance and accuracy of the method and equipment structure, the friction welding pistons produced in the same batch have poor consistency in length and size, resulting in a large difference between the weight of the piston and the size of the internal cooling oil chamber produced after welding, resulting in a high welding reject rate. High, directly affects the performance of the engine, and the welding flash is large (generally 4-8mm), it needs to be specially processed for the welding flash exposed outside, but the welding flash inside the internal cooling oil cavity cannot be removed, which will affect to the piston cooling effect

Laser welding equipment is complex, high cost, high technical requirements for use and maintenance, the thickness and size of the weldment is limited by the power of the laser, and strict requirements are placed on the cleanliness of the weldment and assembly quality, so its application has great limitations

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