Starting Clutch Thrust Load Transfer for Compact Engine Design
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Solution Overview
Problem
Existing starting clutches for internal combustion engines require an increased diameter of the one-way clutch to accommodate thrust forces, leading to engine upsizing and increased size, which is undesirable for compact designs.
Innovation Solution
A starting clutch design where the one-way clutch is clamped by the inner peripheral edge of a hollow disk portion of the clutch outer, allowing the clutch outer to abut against a flange portion of the drive plate boss, reducing the need for a larger diameter and enabling downsizing by positioning components closer together.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the thrust receiving surface is located on a smaller diameter portion of the drive plate boss, then the structural compactness is improved, but the surface area for receiving thrust becomes insufficient
Solution Approach 1:
The thrust receiving surface is relocated from the radial direction (cylindrical surface) to the axial direction (flange surface). This dimensional shift allows the thrust receiving area to extend in the axial direction rather than requiring increased radial diameter, thereby maintaining a compact boss structure while providing sufficient thrust receiving area.
2Strength
If the outer diameter of the cylindrical portion of the drive plate boss is increased to secure sufficient thrust receiving surface area, then the thrust receiving capability is improved, but the diameter of the one-way clutch and overall engine size increases
Solution Approach 1:
The thrust receiving function is transferred from the radial cylindrical surface to the axial flange surface. This allows the thrust receiving area to be increased without increasing the radial diameter of the boss, thereby preventing increases in one-way clutch diameter and overall engine size while maintaining adequate thrust receiving capability.
Solution Approach 2:
The drive plate boss is segmented into distinct functional zones: a cylindrical portion for supporting the one-way clutch and a flange portion for receiving thrust. This segmentation allows each portion to be optimized independently, with the flange providing thrust reception without requiring the cylindrical portion to be enlarged.
3Strength
If the diameter of the one-way clutch is increased to accommodate sufficient thrust receiving area, then the thrust receiving capability is improved, but the size of the entire internal combustion engine increases
Solution Approach 1:
By relocating the thrust receiving surface to the axial flange direction rather than the radial cylindrical direction, the design enables sufficient thrust reception area without increasing the radial dimensions of the clutch assembly, thereby preventing engine size increase.
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 configuration allows for a reduction in the diameter of the one-way clutch and the clutch outer, resulting in a smaller axial width and weight reduction, thereby restraining engine upsizing and achieving downsizing of the internal combustion engine.
Implementation Method 1
A one-way clutch 020 is interposed between a cylindrical portion 03a of the drive plate boss 03 of the clutch inner 02 which extends toward the center side of the crankshaft and an opening cylindrical portion 011a of the clutch outer boss 011 of the clutch outer 010.
Implementation Method 2
A clutch shoe 06 is provided on a pin 05 projecting from the drive plate 03 so as to be capable of swinging by way of a centrifugal force.
Data Source
AI summary
A starting clutch includes a clutch inner that is secured to and supported by a drive plate boss fitted to a crankshaft near the end thereof. A one-way clutch is fitted to the outer periphery of the cylindrical portion extending inwardly. A clutch outer forms an annular portion that covers the outer periphery of the drive plate. A hollow disk portion covers the inner surface and is rotatably supported by the crankshaft. The one-way clutch is clamped by the inner peripheral edge of the hollow disk portion of the clutch outer from the outer peripheral side in cooperation with the cylindrical portion of the drive plate boss, and the inner peripheral edge of the hollow disk portion of the clutch outer abuts against a flange portion of the drive plate boss extending along the inner surface of the drive plate in the centrifugal direction thereof.