| 摘要 |
The present invention relates to a manufacturing method of a turning gear for a construction machine, comprising hot and cold forging steps. The hot forging step includes: a step of preparing and heating a raw material; an up-setting step of having the raw material formed to be low and wide by pressurizing the raw material; a close die forging step of forming a preliminary tooth form which has upper and lower grooves formed on the upper and lower parts of the upset material respectively and a middle wall formed in between the upper and lower grooves and which is formed preliminarily on the outer circumferential surface of the upset material; and a piercing step of forming a pierced hole by piercing the middle wall. The cold forging step uses a cold extrusion method, which uses a hydraulic press to precisely form a tooth form after the hot forging step. The manufacturing method is provided to precisely form the tooth form by using the cold extrusion method, which uses the hydraulic press, after forming the preliminary tooth form in the hot forging step; to improve the degree of precision and the durability of the tooth form; and to reduce the processing time for the tooth form and loss of raw materials, thereby efficiently using the turning gear for a construction machine. |
