Crankshaft Flywheel Assembly One-Piece Guide Ring Shear Reduction
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Solution Overview
Problem
Low-consumption internal combustion engines with low rotational speed and high torque, especially in stop/start modes, put significant strain on plain bearings, particularly at start-up and during transient cold periods, leading to inefficiencies and increased shear forces on fixing screws when trying to replace two-part plain bearings with rolling bearings.
Innovation Solution
An assembly that replaces the collar with a one-piece guide ring, allowing for a one-piece annular plain bearing bush or inner bearing ring, with axial bores aligned with the crankshaft and flywheel, reducing shear forces and maintaining sufficient fixing screw count while minimizing assembly size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a two-part plain bearing is replaced with a rolling bearing to improve performance in cold conditions, then bearing performance is improved, but the assembly complexity and manufacturing cost increase
Solution Approach 1:
The guide ring is divided into two parts: a first guide ring portion integrated with the crankshaft end portion, and a second guide ring portion that can be separately assembled. This segmentation allows the bearing to function as a complete unit while simplifying assembly and manufacturing processes.
Solution Approach 2:
The first guide ring portion is merged with the crankshaft end portion to form an integrated structure, eliminating the need for separate mounting operations and reducing assembly complexity while maintaining bearing functionality.
2Length of moving object
If the flange is eliminated to reduce assembly size, then axial size is reduced, but the fixing surface area for the flywheel decreases
Solution Approach 1:
The guide ring extends radially outward to provide additional surface area for flywheel fixation, compensating for the reduced axial dimension. This dimensional transition allows the assembly to maintain adequate fixing surface area while achieving compact axial size.
3Device complexity
If a one-piece annular bearing bush is used to simplify the bearing structure, then manufacturing complexity is reduced, but the material choice and raceway optimization are limited
Solution Approach 1:
The guide ring is segmented into two portions, allowing the first portion to be manufactured as a one-piece structure for simplicity, while the second portion can be separately optimized for specific material properties and raceway configurations.
Solution Approach 2:
The guide ring acts as an intermediary element between the crankshaft and flywheel, providing a standardized interface that simplifies the overall assembly while allowing independent optimization of bearing surfaces and materials.
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 provides efficient rotational guidance and reduced shear forces on fixing screws, optimizing the assembly's size and performance, especially in cold conditions, by eliminating the flange and using a one-piece guide ring for better material choice and reduced axial size.
Implementation Method 1
a bearing for guiding the crankshaft relative to a crankcase, in rotation around the axis of revolution
Data Source
Figure 1~2
Figure 3A~3B
Figure 4A~4B
AI summary
To assemble an end portion (12) of a crankshaft (10) defining an axis (100) of revolution, forming at least one first bearing surface (30), turned radially outward, and a shoulder (32), on which threaded holes (34) lead outward, with a flywheel (24) comprising axial bores (36) and a bearing (28) for guiding the crankshaft relative to an engine housing (26) in rotation about the axis of revolution, attachment screws (16) passing through the axial bores of the flywheel and screwed into the threaded holes in the crankshaft end portion are provided, thus rigidly connecting the flywheel to the crankshaft end portion. The guide bearing comprises at least one unitary guide ring (42) positioned on the first bearing surface (30) and having a first transverse surface (44) axially bearing on the shoulder (32). The unitary guide ring comprises axial bores (48) which are aligned with the threaded holes (34) in the crankshaft and the axial bores of the flywheel (36) and have the screws (16) passing therethrough.