Shaft Connector Torque Limiter Welding Fatigue
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing torque limiters face issues with welding part fatigue and breakage due to tensile stress from diametric expansion, leading to reduced lifespan and reliability.
Innovation Solution
The design incorporates annular diametrical protrusions on the first and second members forming the hydraulic passage, with the ends of these protrusions being welded together, reducing stress on the welding parts and preventing breakage from weld penetration issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the hydraulic passage is diametrically expanded to press the tube member to the shaft member for torque transmission, then the frictional connection and torque transmission are improved, but the welding parts constantly receive tensile stress in the diametrical direction causing fatigue and breakage
Solution Approach 1:
The tube member is divided into a first tubular member and a second tubular member that are welded together to form the hydraulic passage. This segmentation allows the welding joint to be positioned optimally and the structure to better distribute stresses, reducing fatigue on the welding part while maintaining the diametrical expansion function for torque transmission.
Solution Approach 2:
The hydraulic passage is designed with specific local geometric features including a stepped configuration where the outer diameter changes along the axial direction. This local quality variation allows the structure to concentrate expansion forces in specific regions while protecting the welding joint from excessive tensile stress, resolving the contradiction between connection strength and welding reliability.
2Power
If the hydraulic passage is extended in the axial direction to provide sufficient pressing force, then the torque transmission capability is improved, but the welding parts are more exposed to cumulative tensile stress over the extended area
Solution Approach 1:
The hydraulic passage incorporates a stepped design where the outer diameter varies along the axial direction, creating dynamic stress distribution patterns. This allows the extended axial structure to provide sufficient torque transmission capability while the varying cross-section redistributes tensile stresses away from the welding joint, preventing cumulative fatigue damage over extended service periods.
Solution Approach 2:
Instead of simply extending the hydraulic passage uniformly in the axial direction, the invention introduces dimensional variation through the stepped configuration. This adds complexity in the radial dimension while extending axially, allowing the welding joint to be positioned in a region of lower stress concentration despite the extended axial length, thus maintaining both power transmission and durability.
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 design significantly reduces stress on the welding parts, preventing breakage and enhancing the lifespan and reliability of the torque limiter by distributing stress more evenly.
Implementation Method 1
oil is sealed in the annular hydraulic passage to diametrically expand the hydraulic passage and reduce the diameter of an inner peripheral surface of the second member of the tube member and press the inner peripheral surface to an outer peripheral surface of the shaft member
Implementation Method 2
the tube member is frictionally connected to the shaft member and a torque is transmitted between the tube member and the shaft member
Implementation Method 3
the ends of the diametrical protrusions are welded to each other
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A first member 170 of a second tube member 111 of a tube member includes an annular diametrical protrusion 181 that protrudes outward in the diametrical direction in one side of a hydraulic passage 126 in the axial direction. A second member 171 of the second tube member 111 includes an inner peripheral surface 242 located outside the hydraulic passage 126 in the diametrical direction in one side of the hydraulic passage 126 in the axial direction and a first diametrical protrusion 201 that is located nearer to the one side in the axial direction than the inner peripheral surface 242 and protrudes inward in the diametrical direction. The diametrical protrusion 181 is butted against the first diametrical protrusion 201 to weld and form the butted parts together.