Calculating method of contact width of lightweight low-friction cam

Abstract

The invention discloses a calculating method of the contact width of a lightweight low-friction cam. The contact width of the cam is increased along with increase of the curvature radius of the crosssection of the cam. The design method comprises the following steps that (1) the curvature radius curve rho alpha of the cross section of the cam is obtained through a cam lift curve h alpha; (2) a valve spring height curve H alpha is obtained through the cam lift curve h alpha and the position relationship between the cam and a valve spring; (3) a valve spring load curve F alpha is obtained through the valve spring height curve H alpha and the elastic coefficient k of the valve spring; and (4) the cam width curve W alpha is obtained according to the valve spring load curve F alpha, the material parameters of the cam and the Hertz contact stress formula. According to the cam structure obtained through the method, the weight of the cam can be reduced, the contact area between the cam and atappet can be reduced, and friction and the fuel consumption of the entire vehicle are further lowered.

Description

technical field [0001] The invention relates to the technical field of auto parts, in particular to a method for calculating the contact width of a light-weight and low-friction cam. Background technique [0002] The increasingly stringent national fuel consumption and emission regulations require auto companies to continue to research and explore energy conservation and emission reduction. The report of the World Aluminum Association pointed out that for every 10% reduction in vehicle weight, fuel consumption can be reduced by 6-8%, and emissions can be reduced by 5-6%. Another study shows that 7.5% of the energy loss during the running of a car comes from the mechanical loss of the engine, of which internal friction accounts for about 70%. The friction work of the engine is reduced by 10%, and the fuel consumption is reduced by about 1.5%. [0003] Therefore, the lightweight of components and the low friction of kinematic pairs are effective ways to realize energy saving...

AI Technical Summary

Problems solved by technology

However, in order to meet the structural strength of the largest cam cross-section radius during design, the contact width of the cam is designed according to the requirements of the maximum force on the cam, resulting in a large margin for the contact width of the cam cross-section with a smaller radius. This not only increases the weight of the vehicle, but also increases the friction between the cam and the tappet, increasing fuel consumption

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