Variable Valve Lift Cam Guide Protrusion Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In variable valve lift apparatuses, precise control of the relative position between cams and the valve opening/closing unit is crucial to prevent interference and ensure reliable operation, as improper alignment can lead to damage and reduced reliability.
Innovation Solution
A multiple variable valve lift apparatus featuring a moving cam with cam guide protrusions and an operating unit, including pins and a controller, allows for controlled axial movement of cams to achieve different valve lifts, with a thinner inserted portion and a thicker shift portion to manage space and reduce interference, and solenoids to actuate pin movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple cams are moved along the axial direction to achieve variable valve lift, then different valve lift levels can be realized, but interference occurs between guiding elements and the valve opening/closing unit when relative position is not exactly controlled
Solution Approach 1:
A guide cam is introduced as an intermediary component between the camshaft and the valve opening/closing unit. The guide cam includes a guide surface that precisely guides the axial movement of the camshaft, ensuring accurate relative positioning between the camshaft and valve mechanism. This intermediary guide surface prevents interference by maintaining exact control over the axial direction motion, thereby resolving the contradiction between achieving variable valve lift and preventing element interference.
2Reliability
If precise control of relative position between cams and valve opening/closing unit is implemented, then interference is prevented, but device complexity increases due to additional guiding mechanisms
Solution Approach 1:
The guide cam is integrated with the camshaft as a unified component, merging the camshaft structure with the guiding function. The guide cam includes a guide surface that is formed as part of the camshaft assembly, eliminating the need for separate guiding mechanisms. This merging approach achieves precise axial positioning control while minimizing device complexity by combining multiple functions into a single integrated component.
3Volume of moving object
If the inserted portion is made thinner than the shift portion, then space is reduced and interference is minimized, but manufacturing precision requirements increase
Solution Approach 1:
The cam guide protrusion is designed with non-uniform thickness, where the inserted portion has a smaller thickness than the shift portion. This local quality variation allows the inserted portion to pass through limited axial space between pins while the shift portion provides sufficient engagement length for reliable cam positioning. The gradual thickness transition from the inserted portion to the shift portion is designed to minimize stress concentration and ensure smooth movement, balancing space efficiency with manufacturing 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 enhances the reliability of cam shift operations by allowing multiple valve lifts with improved control, reducing the risk of interference and maintaining apparatus integrity, while allowing for efficient axial directional movement within limited space.
Implementation Method 1
The operating unit may include a solenoid actuated under control of the controller, and the cam guide protrusions may be inserted between the pins so as to be guided when the pin is jutted by the solenoid.
Data Source
AI summary
A multiple variable valve lift apparatus may include a moving cam formed in a hollow cylindrical shape into which a camshaft is inserted. In particular, the moving cam rotates together with the camshaft, moves in an axial direction of the camshaft, and includes a cam guide protrusion and a plurality of cams realizing different valve lift with each other. Moreover, the apparatus includes: an operating unit selectively guiding the cam guide protrusion; a controller controlling the operating unit; a valve opening/closing unit contacting with any one cam of the cams; and at least two pins disposed at the operating unit so as to guide the cam guide protrusion. The cam guide protrusion includes an inserted portion being selectively inserted between the pins and a shift portion.