Starter Pinion Axial Fixation via Split Retaining Disk
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Solution Overview
Problem
Existing starter arrangements for internal combustion engines face challenges in securely fixing the starter pinion and protecting components from excessive centrifugal forces, while also requiring materials that can withstand Hertzian pressures and mechanical loads.
Innovation Solution
A claw coupling is used between the starter pinion and the roller collar with axial teeth, where a split retaining disk secures the pinion axially and a spring protects against centrifugal forces, allowing for separate materials and manufacturing processes for optimal mechanical matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a snap ring or retaining ring is used to secure the pinion, then the pinion can be fixed in place, but the components are exposed to excessive centrifugal forces and cannot be adequately protected
Solution Approach 1:
The spring element is installed internally within the pinion assembly, nested between the pinion and the roller collar. This internal installation protects the spring from excessive centrifugal forces while maintaining its function of securing the pinion axially during assembly of the freewheel.
Solution Approach 2:
The pinion assembly is segmented into separate functional components: the pinion itself, the roller collar, and the spring element. This segmentation allows each component to be optimized for its specific function and protected appropriately, with the spring element being internally installed to shield it from centrifugal forces.
2Adaptability or versatility
If the pinion and roller collar are made as separate components, then different materials can be used to optimize mechanical performance, but the assembly complexity increases
Solution Approach 1:
The pinion and roller collar are combined into a single integrated component with unified toothing. This merging simplifies the assembly while still allowing different material selections for the pinion and roller collar portions, as they can be manufactured as separate pieces and then joined together.
Solution Approach 2:
The pinion assembly uses composite construction with different materials for different portions - the pinion can be made from one material optimized for its function, while the roller collar is made from another material optimized for its function, creating a composite structure that leverages the strengths of each material.
3Power
If axial teeth are used for the claw coupling between pinion and roller collar, then torque transmission is improved, but the manufacturing precision requirements increase
Solution Approach 1:
Instead of cutting axial teeth into the pinion and roller collar separately and then aligning them, the axial toothing is formed as an integrated feature during the molding or forming process. This inversion of the manufacturing approach - forming the toothing as part of the basic shape rather than adding it separately - reduces the precision requirements for subsequent alignment operations.
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 secure axial fixation of the starter pinion, protects against excessive forces, and allows for optimal material selection, enhancing the mechanical performance and reliability of the starter arrangement.
Implementation Method 1
A spring or a spring element that acts on the starter pinion is protected from excessive centrifugal forces due to its internal installation
Data Source
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AI summary
The electric machine (10) has a toothed ring (25), where a turning pinion (22) is positioned. The turning pinion is driven over a freewheel (137), where the turning pinion and a roller collar of the freewheel are executed as separate components. The turning pinion and roller collar are movable relative to each other, and are arranged concentric to each other.