Variable Valve Train Camshaft Lubrication via Axial Shift
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Solution Overview
Problem
The existing lubricating structure of variable valve trains is complex and costly due to the need for multiple lubricant oil passages and supply openings, which complicates the manufacturing process and increases costs.
Innovation Solution
A simplified lubricating structure featuring a camshaft with a single lubricant oil passage and cam communicating oil holes, and a cam carrier with radially formed cam lubrication holes, allowing for efficient lubrication of cam surfaces through axial shifting without a special oil supply changeover mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple lubricant oil passages and supply openings are formed in the control shaft to supply lubricant oil to different lubrication areas, then the lubrication effectiveness is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent applies the dynamics principle by making the cam carrier axially movable relative to the camshaft. Through axial movement, different cam lobes are brought into engagement with the valve, and correspondingly, different cam lubrication holes are positioned to communicate with the single cam communicating oil hole. This dynamic repositioning allows a single oil passage to serve multiple lubrication areas at different operational states, resolving the contradiction between lubrication effectiveness and structural complexity.
Solution Approach 2:
The patent employs the dimensionality change principle by utilizing axial movement (adding a dimensional degree of freedom) to switch between different lubrication configurations. Instead of providing separate oil passages for each cam lobe in the radial direction, the system uses axial displacement to bring different cam surfaces into communication with the single oil supply, thereby simplifying the passage structure while maintaining effective lubrication.
2Reliability
If multiple lubricant oil passages and supply openings are formed in the control shaft to supply lubricant oil to different lubrication areas, then the lubrication effectiveness is improved, but the manufacturing cost increases
Solution Approach 1:
The patent applies the dynamics principle by making the cam carrier axially movable relative to the camshaft. Through axial movement, different cam lobes are brought into engagement with the valve, and correspondingly, different cam lubrication holes are positioned to communicate with the single cam communicating oil hole. This dynamic repositioning allows a single oil passage to serve multiple lubrication areas at different operational states, resolving the contradiction between lubrication effectiveness and structural complexity.
Solution Approach 2:
The patent employs the dimensionality change principle by utilizing axial movement (adding a dimensional degree of freedom) to switch between different lubrication configurations. Instead of providing separate oil passages for each cam lobe in the radial direction, the system uses axial displacement to bring different cam surfaces into communication with the single oil supply, thereby simplifying the passage structure while maintaining effective lubrication.
3Adaptability or versatility
If a special structure is provided to supply lubricant oil to different lubrication areas during changeover operation, then the lubrication adaptability is improved, but the device complexity increases
Solution Approach 1:
The patent applies the dynamics principle by making the cam carrier axially movable relative to the camshaft. Through axial movement, different cam lobes are brought into engagement with the valve, and correspondingly, different cam lubrication holes are positioned to communicate with the single cam communicating oil hole. This dynamic repositioning allows a single oil passage to serve multiple lubrication areas at different operational states, resolving the contradiction between lubrication effectiveness and structural complexity.
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 configuration enables effective lubrication of cam surfaces, reduces manufacturing complexity and costs, and enhances the usability of the variable valve train by simplifying the lubrication system.
Implementation Method 1
a camshaft (42, 52) including therein a lubricant oil passage (42h, 52h) along a longitudinal axis of the camshaft, and a cam communicating oil hole (42hb, 52hb) radially formed from the lubricant oil passage to an outer peripheral surface of the camshaft
Data Source
AI summary
An engine camshaft has a lubricating oil passage formed along the longitudinal axis of the same, a cam communicating oil hole is radially formed from the lubricating oil passage to an outer peripheral surface of the camshaft at the same axial position as an engine valve. Cam lubrication holes are radially formed from the inside to cam surfaces of cam lobes formed around a cam carrier fitted around the camshaft. One of the cam lubrication holes of the cam lobes shifted to a position for operating the valve communicates with the cam communicating oil hole of the camshaft to supply lubricant oil.