Design method for profile of offset elliptical pin hole of piston

Abstract

The invention relates to the technical field of aluminum pistons of gasoline engines, in particular to a design method for a molded line of an offset elliptical pin hole of a piston. The invention discloses a design method for a molded line of an offset elliptical pin hole of a piston. The design method specifically comprises the following steps: S1, determining boundary conditions of an engine; S2, determining the offset angle beta of the piston, wherein the calculation formula of beta is as follows; S3, after the angle beta value is obtained, designing an initial ellipse, defining the initial ellipticity S of the piston ellipse with the upper generatrix of the piston as the long axis, wherein the long axis of the piston pin hole ellipse is Rp + S, the short axis of the piston pin hole ellipse is Rp, and the equation is shown in the description; S4, simplifying the above formula to obtain a new formula shown in the description, wherein the angle theta is 0-360 degrees; S5, rotating the long shaft anticlockwise by an angle beta to obtain an offset elliptic molded line, wherein the equation is shown in the specification; S6, determining a final value of the ellipticity S of the piston pin hole. Compared with the prior art, on the basis of a traditional pin hole molded line, the ellipse and the offset angle beta are designed, contact of the piston pin hole is optimized, and therefore the safety risk of the piston pin hole is reduced.

Description

technical field [0001] The invention relates to the technical field of aluminum pistons for gasoline engines, in particular to a design method for offset elliptical pin-hole profiles of pistons. Background technique [0002] With the increase of the explosion pressure of the engine, the support of the pin hole of the piston pin seat becomes more and more stringent under the requirement of reducing the weight of the piston. The bearing surface of the piston pin hole is reduced, and the output power is increased. Piston pin hole has become the difficulty of piston design. [0003] The power transmission route of the traditional engine is that the combustion chamber converts the chemical energy of the combustion chamber composed of the piston and the cylinder head into mechanical energy, and then through the crank mechanism (such as image 3 shown) to convert the reciprocating motion of the piston into the circular motion of the crank 2. In the process of power transmission, ...

AI Technical Summary

Problems solved by technology

As the angle between the gas pressure and inertial force received by the piston body 6 and the stroke of the supporting force provided by the connecting rod 3 increases, the contact distance increases, and the shear stress on the piston pin hole will also increase, causing cracks to easily occur in the piston pin hole.

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