A kind of motorcycle engine connecting rod and its manufacturing process

Abstract

The invention discloses a motorcycle engine connecting rod and its manufacturing process. The engine connecting rod has a rod body, a large head and a small head are respectively arranged at two ends of the rod body, and a crank pin mounting hole is arranged on the large head. A piston pin installation hole is provided on the small head, and a copper layer is plated on the surface of the shaft, the large head and the small head, and the thickness L of the copper layer is 0.05mm-0.09mm. The manufacturing process of the engine connecting rod is: 1) blanking; 2) forging blank; 3) normalizing treatment; 4) shot blasting treatment; 5) carburizing and quenching treatment; 6) copper plating treatment; 7) machining out Crank pin mounting holes and piston pin mounting holes. The invention delays the surface oxidation process of the connecting rod by increasing the copper plating treatment, reduces the chance of cracks, and improves the service life of the invention; it has the characteristics of easy realization, low cost, long life and light weight.

Description

technical field [0001] The invention belongs to the field of engines, and in particular relates to a motorcycle starting connecting rod and a manufacturing process thereof. Background technique [0002] The connecting rod is an important part of the motorcycle engine. Its function is to transmit the force acting on the piston to the crankshaft, so that the reciprocating linear motion of the piston is converted into the rotary motion of the crankshaft. At present, in order to meet the performance requirements of domestic motorcycle engine connecting rods while ensuring sufficient strength and rigidity, the rod body is made thicker. Although the cross-section adopts an "I"-shaped structure, the thinnest part is more than 4 mm. The overall mass of the connecting rod is relatively large. During high-speed reciprocating motion, due to the huge acceleration, especially at the top dead center and the bottom dead center, the acceleration generates a huge inertial force, which acts o...

AI Technical Summary

Problems solved by technology

Therefore, if the carburizing process is improper and the carbon concentration is too high, it is easy to form coarser massive carbides at the sharp corners of the workpiece, destroying the continuity of the matrix structure

Due to the existence of massive carbides, cracks are likely to occur on the layer with the largest tensile stress, and accelerate the formation and expansion of cracks, reducing the fatigue strength of the connecting rod, which eventually leads to fatigue fracture of the engine connecting rod

The selection of appropriate carburizing and quenching parameters and the prevention of oxidation on the surface of the connecting rod have not been a technical breakthrough until now.

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