Lifter Structure Rotation Prevention via Extraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing lifter structures in internal combustion engines face issues with tilting during reciprocal movement, leading to abnormal noise and potential wear, and difficulty in finish processing due to the integrated stopper protruding outside the cylindrical portion.
Innovation Solution
A lifter structure featuring a cylindrical member with engagement grooves and a separate rotation-preventing member that inserts into these grooves to prevent rotation, allowing for increased sliding length and easier finish processing by avoiding protrusion and interference with the cam's rotation locus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the cylindrical portion is extended to increase sliding distance, then tilting is reduced, but the stopper intrudes into the rotation locus
Solution Approach 1:
The stopper function is extracted from the cylindrical portion and implemented as a separate rotation-preventing member (insertion portion) that engages with the engagement groove. This allows the cylindrical portion to be extended for increased sliding distance without the stopper intruding into the cam's rotation locus, as the rotation prevention mechanism is now distinct and positioned differently.
Solution Approach 2:
The rotation prevention function is segmented from the cylindrical portion structure. The engagement groove and insertion portion form a separate mechanism that prevents rotation independently, allowing the cylindrical portion to focus on providing sliding distance while the separate insertion portion handles rotation prevention without interfering with the cam rotation.
2Reliability
If the stopper protrudes outside the cylindrical portion, then rotation is prevented, but finish processing becomes difficult
Solution Approach 1:
The rotation prevention function is extracted as a separate insertion portion that engages with the engagement groove formed in the cylindrical portion's outer periphery. The insertion portion does not need to protrude outside the cylindrical portion, allowing the outer periphery to be ground continuously in a through-feed manner while still maintaining effective rotation prevention through the engagement groove mechanism.
Solution Approach 2:
Instead of having the stopper protrude outward to prevent rotation, the solution inverts the approach by forming an engagement groove in the cylindrical portion and having an insertion portion engage with it. This allows rotation prevention to be achieved through internal engagement rather than external protrusion, enabling continuous finish processing.
3Stability of the object's composition
If the cylindrical portion is extended, then tilting is reduced, but the stopper position becomes problematic
Solution Approach 1:
The stopper is extracted as a separate insertion portion that engages with the engagement groove. This separate positioning mechanism allows the cylindrical portion to be extended for improved stability without complicating the stopper position, as the insertion portion can be independently positioned to engage with the groove at the appropriate location.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A lifter structure includes a cylindrical member (20) configured to be reciprocally slid in a guide hole (95, 95E) of a lifter guide (95) according to rotation of a cam (70, 70E) and having an engagement groove (22A, 22B) and a rotation-preventing member (40) which is separate from the cylindrical member (20) and is disposed so as to face an interior of the guide hole (95, 95E). The rotation-preventing member (40) is inserted into the engagement groove (22A, 22B) to abut against a groove edge of the engagement groove (22A, 22B) in a rotation direction of the cylindrical member (20), thereby preventing the cylindrical member (20) from rotation in the guide hole (95, 95E).