Propeller Shaft Weak-Point Layout to Prevent Yoke Leakage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The conventional propeller shaft fails to consider the relationship between the torsional strength of the sleeve yoke and the stub shaft, leading to the sleeve yoke being the weakest part and potentially causing lubricant leakage if damaged.
Innovation Solution
The propeller shaft is structured such that the stub shaft has a weakest part with reduced torsional strength, positioned where it overlaps with a vehicle mounting member, ensuring the sleeve yoke has greater torsional strength than the stub shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sleeve yoke is designed with sufficient torsional strength, then the reliability of the propeller shaft is improved, but the device complexity increases due to the need to balance strength distribution among components
Solution Approach 1:
The stub shaft is designed with non-uniform cross-sectional area, creating a localized weakest part with reduced torsional strength. This allows the sleeve yoke to maintain high torsional strength while the overall system has a controlled failure point, resolving the contradiction between reliability and design complexity.
2Ease of manufacture
If the stub shaft is designed with uniform strength, then the manufacturing process is simplified, but the sleeve yoke becomes the weakest part causing potential lubricant leakage
Solution Approach 1:
Instead of uniform design, the stub shaft incorporates a localized reduction in cross-sectional area to create a weakest part. This non-uniform design ensures the stub shaft fails before the sleeve yoke, preventing lubricant leakage, while remaining manufacturable through standard machining processes.
3Strength
If the sleeve yoke torsional strength is increased beyond the stub shaft, then the propeller shaft integrity is maintained, but the risk of lubricant leakage increases due to sleeve yoke damage
Solution Approach 1:
The stub shaft is deliberately designed with a weakest part that will fail first under excessive torsional load, preventing the sleeve yoke from being damaged. This preliminary design choice counteracts the potential harmful effect of lubricant leakage by ensuring the failure occurs in a controlled location rather than in the sleeve yoke.
Data Source
AI summary
A propeller shaft for transmitting driving force of a vehicle includes a first shaft unit mounted to the vehicle via a vehicle mounting member. The first shaft unit includes a sleeve yoke, a stub shaft, and a tube. The sleeve yoke is connected to an output shaft of a transmission of the vehicle, and receives the driving force via the output shaft. The stub shaft is disposed oppositely to the sleeve yoke in a direction of a rotational axis of the first shaft unit. The tube connects the sleeve yoke and the stub shaft. The stub shaft includes a weakest part structured to be less in torsional strength than a remaining part of the first shaft unit and formed at a position at which the stub shaft overlaps with the vehicle mounting member in the direction of the rotational axis.