Variable Valve Rocker Material Differentiation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing variable valve devices for internal combustion engines require extensive machining and heat treatment, increasing costs and machining man-hours due to the use of iron-based metal materials for both cam follower and valve drive rockers, despite only the cam follower rocker needing high impact resistance and the valve drive rocker needing high accuracy.
Innovation Solution
The variable valve device design alternates between using iron-based metal for the cam follower rocker and a different material, such as aluminum, for the valve drive rocker, eliminating the need for heat treatment and reducing machining complexity by prioritizing accuracy over strength for the valve drive rocker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If iron-based metal material is used for both cam follower rocker and valve drive rocker, then strength is improved, but machining man-hours and cost increase
Solution Approach 1:
The patent applies different materials to different parts based on their specific functional requirements. The cam follower rocker, which requires high strength to withstand impact loads, is made of iron-based metal material. The valve drive rocker, which requires high accuracy but not high strength, is made of non-iron-based metal material. This local differentiation of material properties resolves the contradiction by applying strength-enhancing materials only where necessary, thereby reducing overall machining complexity and man-hours while maintaining required strength.
2Strength
If quenching and polishing are carried out on valve drive rocker, then strength is improved, but machining man-hours and cost increase
Solution Approach 1:
The patent eliminates the need for heat treatment and associated polishing operations on the valve drive rocker by selecting a non-iron-based metal material that does not require quenching. This material selection resolves the contradiction by making the manufacturing process simpler while still meeting the accuracy requirements of the valve drive rocker, thereby reducing machining man-hours and cost without compromising the necessary quality.
Data Source
AI summary
A variable valve device includes a camshaft which is rotatably provided in an internal combustion engine while having a cam, a rocker shaft which is arranged next to the camshaft, a valve which is driven by the cam, a cam follower rocker which is rotatably provided in the rocker shaft, and is rocked by following the cam, a valve drive rocker which is rotatably provided in the rocker shaft next to the cam follower rocker, and drives the valve, and a switching portion which be able to switch the valve drive rocker between a drive state and a non-drive state. Either a body of the cam follower rocker or a body of the valve drive rocker is made of an iron-based metal material, and the other body is made of a material different from the iron-based metal material, heat treatment being not required in the different material.