Valve Timing Lock Pin Stepped Surface Clearance Adjustment
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Solution Overview
Problem
Conventional valve timing control devices for internal combustion engines have a complex assembly process and a high number of components, leading to decreased working efficiency in adjusting the clearance between the lock pin and lock hole, which results in increased noise and reduced engine performance.
Innovation Solution
A valve timing control device with a lock pin featuring a first shaft portion and a second shaft portion of smaller diameter, where the second shaft portion has a longer axial length than the lock recessed portion depth, and a stepped surface between the two, allowing for precise adjustment of clearances without the need for visual inspection or additional components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a through hole is formed in the bottom wall of the housing for visual inspection of the clearance between the lock pin and the lock hole, and an eccentric bolt is provided to the shoe for fine adjustment, then the clearance can be adjusted with high accuracy, but the number of components is remarkably increased and the adjustment operation becomes complicated
Solution Approach 1:
The invention extracts and eliminates unnecessary components (through hole and cap) from the housing structure. The clearance adjustment is achieved by directly modifying the lock pin structure itself, removing the need for visual inspection holes and closing caps, thereby reducing component count while maintaining adjustment capability.
Solution Approach 2:
The invention merges the adjustment function into the lock pin structure by providing a tapered portion directly on the lock pin that engages with the lock hole. This combines the locking and adjustment functions into a single integrated structure, eliminating the need for separate adjustment mechanisms and reducing overall device complexity.
2Manufacturing precision
If a through hole is formed in the bottom wall of the housing for visual inspection of the clearance, and an eccentric bolt is provided to the shoe for fine adjustment, then the clearance can be adjusted with high accuracy, but the adjustment operation becomes complicated and working efficiency deteriorates
Solution Approach 1:
The invention removes the through hole and cap components from the housing, eliminating the need for visual inspection during assembly. The clearance adjustment is performed directly through the tapered lock pin structure, significantly simplifying the adjustment operation and improving working efficiency.
Solution Approach 2:
The lock pin is pre-formed with a tapered portion during manufacturing, which automatically provides the correct clearance when engaged with the lock hole. This preliminary preparation eliminates the need for complex adjustment operations and visual inspection, allowing for rapid and accurate assembly.
3Reliability
If the second shaft portion of the lock pin has an axial length longer than the depth of the lock recessed portion, then precise engagement and disengagement is achieved, but the lock pin structure becomes more complex
Solution Approach 1:
The lock pin incorporates a tapered portion that enables dynamic engagement and disengagement. The tapered geometry allows the lock pin to smoothly transition between locked and unlocked states, improving reliability while maintaining a relatively simple structure through geometric design rather than additional components.
Data Source
AI summary
A valve timing control device includes: a first clearance being formed between a radial other side of the outer circumference surface of the first shaft portion, and a confronting end surface of a radial other side of the inner circumference surface of the sliding hole, a second clearance being formed between an outer circumference of the second shaft portion on a side of the first clearance, and a radial other side of the inner circumference surface of the lock recessed portion, a stepped surface being formed at a connection portion between the first shaft portion and the second shaft portion, and having a stepped width in a radial direction, and a width of the second clearance being substantially identical to the width of the stepped surface.