Precise forming method for automobile engine hollow valve blank with core bar

Abstract

The invention belongs to the technical field of metal plastic forming, and particularly provides a method for transverse rolling forming of an engine hollow valve blank. The transverse rolling method is used for symmetrically machining the hollow blank of a hollow valve; a conical table and a spherical table are formed on the machined hollow blank, and then a disc portion of the hollow valve is formed through die forging. Compared with the traditional solid valve drilling and backward extrusion process, the transverse rolling process is used for producing the automobile engine hollow valve blank, and the method has the advantages that production efficiency is high, and 6-12 blanks can be manufactured every minute through one machine; the material utilization rate is improved; the overall streamline distribution in the valve is reasonable, and the tissue is fine; all parts of the blank deform, a refined and even grain structure can be obtained, and the overall mechanical property of the valve can be conveniently improved.

Description

technical field [0001] The invention belongs to the technical field of metal plastic forming, and in particular provides a method for forming engine hollow valve blanks by cross-wedge rolling, which is suitable for the production of small-diameter (generally considered d<20mm) hollow shaft blanks rolled by cross-wedge rolling with a mandrel . Background technique [0002] The valve is a key part of the engine valve train. The opening and closing of the valve allows the combustible gas to enter the cylinder and discharge the exhaust gas after combustion. The hollow valve realizes light weight, and because the hollow part seals a certain volume of metal sodium, the thermal conductivity is effectively improved. During the working process of the engine, there are frequent collisions between the valve disc and the valve seat, and they are eroded by high-temperature and high-pressure gas, especially a large load is applied to the valve neck. Therefore, the valve must not only ...

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Problems solved by technology

[0003] The commonly used hollow valve production method in China is the solid valve drilling method. This method can only obtain hollow valves with a hollow stem and a solid disc, and the productivity is low, and the material utilization rate is low, especially for rotary valves with different shapes and sizes. Hollow air valve composed of body, resulting in material waste

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