Variable Compression Ratio Engine Assembly Pin Offset
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Solution Overview
Problem
The existing variable compression ratio internal combustion engine design requires detaching the bearing cap to insert the first coupling pin, complicating assembly and reducing workability.
Innovation Solution
A variable compression ratio mechanism with a second control shaft and lever system allows the first coupling pin to be positioned away from the bearing cap at a given compression ratio position, enabling assembly without removing the bearing cap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the first coupling pin is positioned to overlap with the bearing cap in the axial direction, then the structural compactness is improved, but the assembly workability deteriorates because the bearing cap must be detached for insertion
Solution Approach 1:
The patent resolves the spatial conflict between the first coupling pin and bearing cap by changing the positioning from an axial overlap (one-dimensional conflict) to a radial offset arrangement. The first coupling pin is positioned at a location away from the bearing cap in the radial direction, allowing both components to coexist without interference. This dimensional repositioning enables assembly without detaching the bearing cap while maintaining structural compactness.
2Ease of operation
If the bearing cap is detached to insert the first coupling pin, then the insertion space is created, but the assembly time increases and productivity decreases
Solution Approach 1:
The patent applies preliminary action by pre-positioning the first coupling pin at a location that does not interfere with the bearing cap installation. The coupling pin is arranged in advance at a radial position away from the bearing cap, so that when the bearing cap is installed, no disassembly is needed. This preliminary spatial arrangement eliminates the need for detaching and reattaching components during assembly, thereby improving productivity.
3Ease of manufacture
If the first coupling pin is arranged away from the bearing cap, then the assembly workability is improved, but the space requirement increases
Solution Approach 1:
The patent applies local quality by creating a localized clearance zone around the bearing cap area. Instead of uniformly increasing the overall engine space, the first coupling pin is positioned at a specific radial location away from the bearing cap, creating only the minimum necessary local space. This localized spatial arrangement improves assembly workability while minimizing the impact on overall space requirements.
Data Source
AI summary
It has variable compression ratio mechanism (10) that changes engine compression ratio depending on the rotational position of first control shaft (14). First control shaft (14) and second control shaft, which is connected to a motor, are coupled together by lever (24) of coupling mechanism (20). First arm portion (25) of first control shaft (14) and one end of lever (24) are rotatably coupled together by first coupling pin (26). When viewed in the axial direction of this first coupling pin (26), at least at a given compression ratio position, first coupling pin (26) is arranged at a position away from bearing cap (30) that is for rotatably supporting first control shaft (14).