Upper die anti-cracking structure of closed type cold extrusion planetary gear die

Abstract

The invention discloses an upper die anti-cracking structure of a closed type cold extrusion planetary gear die, which comprises a positioning structure and a die body, wherein the positioning structure comprises an upper die sleeve and a lower die sleeve which have the same internal hole diameter; and the die body comprises an upper die, a lower die, an upper ejector rod and a lower ejector rod.A die cavity of the upper disk die is of a tooth form, an intermediate shaft hole is in clearance fit with the upper ejector rod, the die cavity of the lower disk die is a concave pit, and the intermediate shaft hole is in clearance fit with the lower ejector rod. The plane at the lower end of the upper ejector rod is 0.5-1.5mm higher that the plane at the top end of the die cavity of the upper die, and the diameter of the bottom end of the upper ejector rod is equal to the diameter of a dedendum circle in the die cavity of the upper die. The internal stress borne by the upper die is transferred to the upper ejector rod through the improved structure, thus the cracking of the upper die is effectively avoided. In addition, the upper ejector rod is not easy to crack due to the borne pressure. The invention has the advantages of simple structure, easiness for manufacture and good anti-cracking effect, and is suitable for upper dies of closed type cold extrusion planetary gear dies with different specifications.

Description

technical field [0001] The invention relates to a metal extrusion die, in particular to a closed cold extrusion planetary gear die. Background technique [0002] Closed cold extrusion belongs to a precision forging process, which is characterized in that the billet is placed in the mold at room temperature, and the matching upper and lower molds are closed under a certain clamping force, and then the upper ejector is accompanied by the upper and lower molds. The mold moves down together and hits the static lower ejector rod to form extrusion force, and the billet built in the mold cavity is further extruded. Compared with conventional open die forging, closed cold extrusion has the following main advantages: first, the billet is cold extruded in a closed die cavity, with dense metal structure and high strength; secondly, the billet is not heated, and there is no high-temperature oxidation problem , no worry about decarburization; another is that the forging has no flash, th...

AI Technical Summary

Problems solved by technology

The manufacturing cost of the closed cold extrusion die is high, and the economic loss due to cracking failure is large, which directly affects the further popularization and application of the closed cold extrusion process

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