Eccentric Shaft Backlash Adjuster for Cam Gear Miniaturization
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Solution Overview
Problem
Existing cam driving gear mechanisms for internal combustion engines require external components for backlash adjustment, leading to poor space efficiency and increased engine size.
Innovation Solution
A backlash adjusting device that uses an eccentric supporting shaft to adjust the clearance between driving and driven gears, with the adjusting portion located inside the engine and the fixing portion on the base shaft, reducing external components and allowing miniaturization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the adjusting portion and fixing portion are both exposed to the outside of the cylinder block with a flange portion requiring external adjustment space, then the backlash can be adjusted, but the space efficiency on the outside of the internal combustion engine deteriorates and the engine size increases
Solution Approach 1:
The adjusting portion is nested inside the eccentric supporting shaft, with the adjusting member positioned within the hollow interior of the shaft. The fixing portion is integrated into the base shaft structure, eliminating the need for external flange portions and adjustment spaces. This nesting arrangement allows backlash adjustment functionality to be contained within the engine's existing structural envelope, improving space efficiency while maintaining adjustment capability
Solution Approach 2:
The adjusting portion and fixing portion are merged into the internal structure of the eccentric supporting shaft and base shaft assembly. The adjusting member is combined with the hollow interior of the eccentric supporting shaft, and the fixing member is integrated into the base shaft, creating a compact unified structure that eliminates separate external components and reduces overall engine size
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 solution reduces the number of external components, miniaturizes the engine, and prevents noise by allowing precise backlash adjustment within the engine, enhancing space efficiency and performance.
Implementation Method 1
an eccentric supporting shaft rotatably supports at least one of the driving gear and the driven gear on an outer circumference of the eccentric supporting shaft, and has a central axis eccentric with respect to a center of an axis of rotation of the driving gear or the driven gear
Implementation Method 2
a fixing portion for fixing the eccentric supporting shaft to the base shaft by fixing means screwed to the base shaft on the axis of the base shaft
Data Source
AI summary
An internal combustion engine includes, among other things, a backlash adjusting device. An eccentric supporting shaft is disposed in an internal combustion engine so as to be able to be fixed at a predetermined rotational angle position about a central axis. The shaft adjusts an amount of clearance between a pair of gears, and is fitted over a base shaft fixed to the internal combustion engine such that the central axis of the eccentric supporting shaft coincides with an axis of the base shaft. An adjusting portion allows an inner circumference of the eccentric shaft to be fitted over an outer circumference of the base shaft at a predetermined rotational angle position. A fixing portion is configured to fix the eccentric supporting shaft to the base shaft.