Rocker Arm Axial Movement Restriction in Variable Valve Engines
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Solution Overview
Problem
Conventional internal combustion engines with variable valve timing systems face challenges in positioning the bearing for rocker-arm shafts, leading to inadequate restriction of the rocker arm's sliding movement, and increasing the number of components when a separate blocking member is used.
Innovation Solution
The engine employs a stopper mechanism with engagement nails and protruding pieces to restrict the rocker arm's axial movement within a predetermined amount, using a simple structure without adding extra components, and includes engagement grooves and position-restriction portions to facilitate smooth sliding and accurate restriction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the bearing end face is used as position-restriction means, then no extra components are needed, but the bearing material (aluminum alloy) is too weak to withstand the impact from rocker arm sliding movement
Solution Approach 1:
The patent combines the position-restriction function with the stopper mechanism by integrating position-restriction portions directly onto the stopper. This merging allows the stopper to simultaneously perform both stopping and position-restriction functions, resolving the contradiction between component simplicity and sufficient strength for impact resistance.
2Strength
If a separate blocking member is used to restrict sliding movement, then the position-restriction function is adequate, but the number of component parts increases
Solution Approach 1:
The patent merges the position-restriction function into the existing stopper component by adding position-restriction portions to it. This integration eliminates the need for separate blocking members while maintaining adequate position-restriction capability, thus resolving the contradiction between functional adequacy and component count.
Solution Approach 2:
The stopper is designed to perform multiple functions: it acts as both a stopping mechanism and a position-restriction means through its integrated position-restriction portions. This multi-functionality reduces the overall component count while maintaining all necessary functions, addressing the contradiction between component simplicity and functional adequacy.
3Shape
If the bearing layout is fixed, then the bearing position is determined, but the position-restriction means cannot be disposed at the appropriate position for effective restriction
Solution Approach 1:
The patent segments the position-restriction function from the bearing layout by using separate position-restriction portions on the stopper. This segmentation allows the position-restriction means to be independently positioned at the most effective location for restricting rocker arm sliding movement, independent of the bearing's fixed layout.
Data Source
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Figure 3(a)~3(b)
AI summary
Object The invention aims to provide an internal combustion engine equipped with a variable valve controlling system which switches the actions of an engine valve by sliding a rocker arm in the axial direction of a rocker-arm shaft and which is capable of restricting the axial-direction movement of the rocker arm within a predetermined amount by means of a simple structure without increasing the number of component parts. Solving Means Position-restriction portions (41) and (42) are formed in a rocker arm (13), and abut on the trigger arm (33) to restrict the sliding movement of the rocker arm (13) within a predetermined amount when the trigger arm (33) is disengaged.