Cam axle underneath type valve mechanism of motorcycle engine

Abstract

The invention provides a camshaft underslung valve mechanism of a motorcycle engine, comprising a camshaft, an air inlet jogger, an air outlet jogger, an air inlet rocker arm, an air outlet rocker arm, an air inlet valve and an air outlet valve. The camshaft of the invention is provided with an air inlet cam and an air outlet cam which respectively push the air inlet jogger and the air outlet jogger by an air inlet tappet and an air outlet tappet with a disc-shaped flat bottom; the axis line of the air inlet tappet and the air outlet tappet are orthogonal with the axis line of the camshaft. The cam profiles of the air inlet cam and the air outlet cam are respectively formed by connecting nine line segments with smooth transition of a line head and a line tail. Therefore, the invention has the advantages of high timing exactness of air inlet and air outlet, good continuity in inlet and outlet processes without mutation of the inertia force, good force transmission performance of a driven part, and high transmission efficiency. The power and the torque of the engine can be improved by 10% to 13%, and the noise can be reduced by about 10dB.

Description

technical field [0001] The invention relates to a gas distribution mechanism of a motorcycle engine, in particular to a camshaft-mounted gas distribution mechanism. Background technique [0002] There are two types of valve trains for motorcycle engines: upper camshaft and lower camshaft. The former engine is commonly called the camshaft-mounted engine, and the latter is commonly called the camshaft-mounted engine (also known as the CG series engine). The former has a relatively simple structure, and it directly pushes the intake and exhaust rocker arms respectively through the intake and exhaust cams on the camshaft to achieve air distribution to the engine cylinders. However, since the upper camshaft is far away from the crankshaft, the driving force must be obtained from the lower crankshaft through a chain drive, so the timing of the gas distribution is poor, resulting in low power, torque and efficiency of the engine . The latter gets the driving force from the crank...

AI Technical Summary

Problems solved by technology

In the case of sharing a cam, either the contour lines of the two cannot meet the design requirements, or the contour line of one of them is sacrificed-at present, most of them are designed according to the intake cam mechanism, that is, the reverse type design, and the exhaust The cam is replaced by the intake cam, so that the opening and closing of the intake and exhaust valves cannot be controlled according to the regular movement during the intake and exhaust process, and the expected timing of gas distribution cannot be realized.

As a result, the power, torque and even efficiency of the existing CG series engines are still low; the valve noise is not easy to control

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