Camshaft Chain Guide Bolt Structure to Prevent Assembly Drop
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The installation of a support bolt in camshaft drive devices is challenging due to the risk of it dropping into the chain chamber during assembly, especially when the bolt is accidentally released, complicating the workability of the process.
Innovation Solution
A camshaft drive device design featuring a support bolt with a longer shaft portion and a head portion that protrudes beyond the insertion hole, allowing for secure positioning and preventing the bolt from falling into the chamber, along with a knob for easier insertion and a non-threaded portion for coaxial alignment, facilitating the installation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the support bolt is inserted through a small insertion hole in the front wall, then the chain chamber can be properly assembled, but the support bolt may accidentally drop into the chain chamber when released, making installation difficult
Solution Approach 1:
The patent applies preliminary anti-action by designing the support bolt with a head portion that protrudes from the front surface of the front wall after insertion. This protruding head prevents the bolt from dropping into the chain chamber by creating a physical barrier before the bolt can fall, thus anticipating and preventing the harmful effect of accidental dropping during installation
Solution Approach 2:
The head portion of the support bolt acts as an intermediary element between the insertion hole and the chain chamber. It occupies the space at the front surface of the front wall, serving as a mediator that prevents direct access of the bolt shaft to the chain chamber interior, thereby preventing accidental dropping while still allowing proper insertion through the small hole
2Reliability
If the shaft portion of the support bolt is made longer to prevent dropping, then the bolt can protrude sufficiently to prevent accidental dropping, but the bolt becomes harder to insert through the limited space
Solution Approach 1:
The support bolt is segmented into distinct functional portions: a head portion for protrusion and prevention of dropping, a shaft portion for insertion through the support hole, and a male screw portion for engagement with the female screw hole. This segmentation allows each portion to be optimized for its specific function - the head is sized for protrusion, while the shaft and screw portions are sized for insertion and engagement
Solution Approach 2:
Different portions of the support bolt have different local qualities optimized for their specific functions. The head portion has a larger diameter for protrusion and handling, the shaft portion has a smaller diameter for fitting through the support hole, and the male screw portion has threaded geometry for engagement. This local differentiation allows the bolt to prevent dropping while remaining insertable
Data Source
AI summary
A cam shaft drive device includes a chain, a guide lever, a chain chamber, which is provided in a cylinder head, a support bolt, which pivotably supports the guide lever, the support bolt including a head portion, a male screw portion, and a shaft portion, which is inserted through the support hole of the guide lever, an insertion hole, which is through which the support bolt is inserted, and a female screw hole, which is provided in the rear wall and into which the male screw portion is screwed, wherein a length from a rear end to a front end of the shaft portion is longer than an axial distance from a front end of the support hole to a front end of the insertion hole in a state where the guide lever abuts on the rear wall.