Piston and manufacturing method thereof

Abstract

The piston comprises a piston outer top, a piston inner top and a piston skirt, the exterior of the piston skirt is connected with the lower portion of the piston outer top through a land weld joint, and the interior of the piston skirt is connected with the lower portion of the piston inner top through an inner cavity weld joint. The upper portion of the piston inner top is connected with the upper portion of the piston outer top through a top face welding seam. The manufacturing difficulty and cost of the piston are reduced, the lightweight index of the piston is improved, and the power-to-weight ratio of an engine is increased. The invention further discloses a manufacturing method applied to the piston. The manufacturing method comprises the steps that the piston outer top, the piston inner top and the piston skirt are forged in a split mode; the piston outer top, the piston inner top and the piston skirt are machined in a split mode; and the piston outer top, the piston inner top and the piston skirt are welded at the inner cavity welding seam, the top surface welding seam and the ring land welding seam. The beneficial effects of the piston outer top, the piston inner top and the piston skirt are the same as those of a manufacturing method.

Description

technical field [0001] The invention relates to the technical field of pistons, in particular to a piston. In addition, the present invention also relates to a manufacturing method applied to the above-mentioned piston. Background technique [0002] With the continuous development of emission upgrades and the continuous improvement of engine thermal efficiency and power-to-weight ratio, heat-resistant alloy steel pistons are one of the inevitable choices. First, alloy steel has better heat resistance and high-temperature strength, and can operate safely at higher gas temperature and higher explosion pressure; second, alloy steel has a high structural rigidity, and the height and weight of the piston can be reduced through structural optimization , thereby reducing engine weight and improving engine power-to-weight ratio. As the core component of the engine, the enhancement of the reliability of the piston is the fundamental guarantee for the improvement of the thermal effi...

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Problems solved by technology

Its defects: single cooling oil chamber structure, insufficient cooling effect of the inner chamber and the inner end of the pin hole, prone to high temperature phenomenon, resulting in high temperature coking of the engine oil and causing wear or seizure of the pin hole; forging is difficult and costly, and the forging blank of the piston skirt has a large physical space , especially large bore pistons require correspondingly large forging strokes and forging pressures, which intensifies forging energy consumption and die loss, and too deep forging is likely to cause poor blank mold filling effect ( figure 2 The forging depth of the inner cavity of the middle piston is relatively deep); the space for weight reduction is small, especially the material removal above the pin seat of the inner cavity is difficult

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