Switchable Cam Follower Mass Moment of Inertia Reduction
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Solution Overview
Problem
Existing cam followers in internal combustion engines have a high mass moment of inertia due to torsion springs, which also occupy unnecessary installation space and increase leverage forces when activated.
Innovation Solution
The torsion spring is seated on an axle journal located near the complementary face of the cam follower, with axle journals protruding from the lever's side walls, allowing the springs to be positioned closer to the pivot center, reducing the mass moment of inertia and minimizing mass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the torsion spring is positioned on the valve-side end of the cam follower, then the spring can be easily installed and maintained, but the mass moment of inertia increases and unnecessary installation space is occupied
Solution Approach 1:
The torsion spring is repositioned from the valve-side end (one dimension) to the pivot region near the complementary face (another dimension), changing the spatial arrangement to reduce the mass moment of inertia while maintaining installation feasibility
Solution Approach 2:
An axle journal is introduced as an intermediary component to mount the torsion spring near the pivot center, allowing the spring to be positioned optimally for low inertia while maintaining structural support and ease of installation
2Weight of moving object
If the start face is displaced further in the direction of the support element to reduce mass moment of inertia, then the inertia decreases, but the leverage forces are drastically increased
Solution Approach 1:
The position parameter of the start face is optimized to a central location rather than being displaced maximally, finding a compromise that reduces mass moment of inertia without causing excessive leverage forces
3Area of stationary object
If the torsion spring is positioned远离 the pivot center, then the spring has more space to operate, but the mass moment of inertia increases
Solution Approach 1:
The torsion spring is repositioned from the valve-side end (one dimension) to the pivot region near the complementary face (another dimension), changing the spatial arrangement to reduce the mass moment of inertia while maintaining installation feasibility
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design reduces the mass moment of inertia and minimizes unnecessary mass, while maintaining structural rigidity and functionality, optimizing the cam follower's performance.
Implementation Method 1
at least one torsion spring is clamped between the two levers as lost motion spring
Data Source
AI summary
A switchable cam follower of a valve train of a combustion engine, which has an external lever that encompasses an internal lever. The levers are pivotably moveable relative to one another at a valve-side end. The cam follower has a stop for a gas exchange valve on an underside on the valve-side end and a complementary face on the other end for a support element. The cam follower has a start face on an upper side for at least one high-lift cam. In one receptacle of the internal lever a coupling element is seated, which is displaceable longitudinally and can be brought into engagement in sections in case of coupling with a driving surface of the external lever. Also, at least one torsion is clamped between the two levers.