Crankshaft Gear Interface With Conical Flange Against Slippage

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Solution Overview

Problem

Existing crankshaft designs in internal combustion engines face challenges in efficiently transmitting torque while minimizing stress concentrations and preventing gear slippage during operation.

Innovation Solution

The design incorporates a conical gear engaging surface on the crankshaft flange with a complementary conical flange engaging surface on the gear, featuring helical teeth that reduce stress concentrations and prevent axial movement of the gear, enhancing torque transmission efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional flat gear interface is used on the crankshaft, then the structure is simple and easy to manufacture, but stress concentrations occur and gear slippage happens during operation

Engineering Contradiction:

Improvegear engagement reliabilityVSAvoidgear interface structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies a conical surface geometry to the gear interface instead of a flat surface. The conical shape distributes stress more evenly across the gear engagement area, eliminating stress concentrations that occur with flat interfaces. The curvature of the conical surface allows for better load distribution and prevents gear slippage while maintaining manufacturing feasibility through standard machining processes.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Reliability

If the conical gear engaging surface extends at a larger angle, then gear slippage is better prevented, but stress concentrations increase

Engineering Contradiction:

Improvegear anti-slippage performanceVSAvoidstress concentration at gear interface

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

The patent optimizes the conical surface angle parameter to balance two competing requirements. By selecting a specific angle range (5-15 degrees relative to the axis of rotation), the design achieves sufficient axial component to prevent gear slippage while keeping the stress concentration within acceptable limits. This parameter optimization resolves the contradiction between preventing slippage and minimizing stress.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the conical surface extends over a longer axial distance, then gear engagement is more secure, but the crankshaft flange size increases

Engineering Contradiction:

Improvegear engagement securityVSAvoidcrankshaft flange axial length

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The patent optimizes the axial extent of the conical surface by controlling the cone angle and the axial length of the flange. The specific angle range (5-15 degrees) allows the conical surface to extend sufficiently axially to provide secure gear engagement while limiting the overall flange length. This parameter optimization ensures reliable gear engagement without excessive increase in crankshaft dimensions.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20250297639A1Engine crankshaft assemblies with gear interfaces

Publication Date: 2025.09.25 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A crankshaft assembly includes a crankshaft body extending along an axis of rotation. The crankshaft body includes bearing journals that are mutually coaxial with the axis of rotation and spaced from each other along a length of the crankshaft body and crankpins that are spaced from each other along the length of the crankshaft body and axially offset from the axis of rotation. The crankshaft body also includes crank webs projecting radially from the axis of rotation and interconnecting the bearing journals and the crankpins and a flange extending from a distal end of the crankshaft body having a conical gear engaging surface.