Quenched and tempered alloy steel split connecting rod of small piston engine and its manufacturing process

Abstract

The invention discloses a quenched and tempered alloy steel expanding connecting rod for a small piston engine and a manufacturing process, provides a feasible and reliable manufacturing process for the quenched and tempered alloy steel connecting rod, and provides a small piston engine with a simple structure, High-strength, light-weight riser link. The manufacturing process method of the expanding connecting rod is provided with an expanding and breaking hole at the big end of the connecting rod, and an expanding and breaking groove for leading cracks is arranged in the expanding and breaking hole, and no mechanical force needs to be applied to the large round hole during the expanding and breaking, which makes the expanding and breaking of the connecting rod easier. , The optimized structure reduces the external surface defects after the connecting rod is expanded and broken, and realizes the expansion and breaking of the quenched and tempered alloy steel connecting rod, which improves the manufacturability and qualification rate of the connecting rod, and effectively improves the reliability of the product; The selection range reduces the manufacturing cost. The manufacturing process of the expanded connecting rod greatly improves the bearing capacity, shear resistance and assembly quality of the connecting rod, and the lubrication effect of the round holes of the large and small ends of the connecting rod is enhanced, and the efficiency is improved.

Description

technical field [0001] The invention relates to the technical field of small aeroengines, in particular to a quenched and tempered alloy steel split connecting rod of a small piston engine and a manufacturing process. Background technique [0002] The connecting rod is one of the key moving parts of the small piston aero-engine, and it undertakes the function of changing the direction and mode of force transmission. Compared with ordinary piston engines, the working conditions of the connecting rods of aviation piston engines are more severe. During the working process, they are subjected to high-frequency periodic impact force, inertial force and bending force of more than 90 to 120 times per second. Manufacturing quality directly affects engine performance and reliability. In the 1990s, connecting rod breaking technology was developed as a new manufacturing process in developed countries of the automobile industry, which fundamentally changed the traditional connecting ro...

AI Technical Summary

Problems solved by technology

In this method, the two kinds of grooves for punching are formed at the same time during the hot forging process, and the root of the groove formed at this time is difficult to achieve the curvature required to generate stress concentration cracks, and the durability of the punching die is also difficult to guarantee, and The connecting threaded hole between the connecting rod cover and the connecting rod body is not machined before breaking, and then processed after the subsequent butt joint, which is obviously poor in workmanship and difficult to guarantee the accuracy, and does not solve the main contradiction that needs to be solved when quenching and tempering alloy steel is broken, that is, the shrinkage of the section The structure of the fracture surface caused by the rate is difficult to control

[0004] Invention patent CN 101307796A announced the "cryogenic embrittlement expansion fracture process of high-strength alloy steel connecting rod". This process is complicated and difficult to control, and it can only be used for specific materials. Engines with ordinary power are not suitable for small aviation piston engines with small alloy steel connecting rods, light weight and high power-to-weight ratio requirements

[0005] At the same time, the above two patents provide connecting rod expansion and breaking methods by opening expansion and breaking grooves in the big head hole and its end surface, and applying mechanical force outward in the big head hole to make the connecting rod free from stress concentration and strength. The lowest expansion groove is broken. This structure is suitable for the structure of setting bearing bushes and bushings in the big end hole of the connecting rod. The generatrix of the big end hole of the connecting rod is an incomplete and continuous cylindrical surface, which cannot be used as the outer raceway of the needle roller bearing. ; Moreover, when the connecting rod structure provided by these patented technologies is broken, a mechanical external force is applied to the wall of the big hole, so that the connecting rod hole is prone to shape deformation and mechanical stress, thereby affecting the reliability and durability of use

Images