Multicylinder Engine Valve System Rocker Arm Inclination
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Solution Overview
Problem
In multicylinder engine valve operating systems, unbalanced thrust loads on the camshaft due to dimensional or assembly errors lead to knocking sounds and reliability degradation, as the rocker arms' incorrect orientation causes uneven reaction forces when interacting with the camshaft and cam holder.
Innovation Solution
The system inclines rocker arms relative to the camshaft axis, either in opposite or the same directions for each cylinder, and uses helical gears on the air and exhaust sides to counteract thrust loads, ensuring balanced forces and preventing axial movement of the camshaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the longitudinal direction of the rocker arm is not correctly orthogonal to the axis of the camshaft due to dimensional error or assembly error, then the valve operating system can still function, but an unbalanced thrust load will act on the camshaft causing knocking sounds and reliability degradation
Solution Approach 1:
The patent applies counterweight principle by introducing balancing masses on the camshaft that counteract the unbalanced thrust loads generated by incorrectly oriented rocker arms. The balancing masses are positioned to generate opposing forces that neutralize the harmful axial thrust components, thereby preventing knocking sounds and reliability degradation while maintaining tolerance for dimensional and assembly errors in rocker arm orientation.
2Stability of the object's composition
If the rocker arm is inclined to counteract thrust load, then axial movement of the camshaft is prevented, but the structure becomes more complex
Solution Approach 1:
The patent employs asymmetry principle by deliberately inclining the rocker arms at specific angles relative to the camshaft axis rather than maintaining perfect orthogonality. This asymmetric configuration generates thrust load components that can be balanced by opposing rocker arms or balancing masses, thereby stabilizing the camshaft position while using a relatively simple structural modification rather than complex adjustment mechanisms.
Data Source
AI summary
A valve operating system for a multicylinder engine opens and closes a pair of valves provided on each of cylinders by means of a pair of rocker arms operated by a cam provided on a camshaft supported on a cam holder. When viewed in a direction of a cylinder axis, the pair of rocker arms of at least one of the cylinders are inclined in opposite directions to each other with respect to a direction orthogonal to a camshaft axis. Therefore, thrust loads acting on the camshaft from the pair of rocker arms are counteracted individually for each of the cylinders, thereby enabling the thrust load to be reduced and axial movement of the camshaft to be prevented.