Laminated Axle Spring Structure for Crack-Resistant Durability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional axle springs for railway vehicles experience durability issues due to cracking and peeling at the upper portion of the innermost elastic body under tensile and compressive loads, which reduces their lifespan while maintaining the required spring characteristics.
Innovation Solution
The axle spring design features an innermost elastic body with varying thicknesses (W1 > W3 > W2) to minimize stress and strain at the upper portion, maintaining the same longitudinal cross-sectional area as conventional designs, thus enhancing durability without compromising spring characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the innermost elastic body is increased to decrease strain rate, then durability is improved, but spring constant is reduced and spring characteristics cannot be ensured
Solution Approach 1:
The elastic body is designed with non-uniform thickness distribution, where the upper portion has greater thickness than the lower portion. This local quality variation allows the upper portion to resist cracking and peeling under tensile and compressive loads while maintaining appropriate spring characteristics through the overall thickness configuration.
Solution Approach 2:
The thickness parameter of the elastic body is changed from uniform to non-uniform distribution. Specifically, the thickness at the upper portion is increased relative to the lower portion, which changes the stress distribution and strain rate characteristics to improve durability while preserving spring functionality.
2Reliability
If the thickness of the innermost elastic body is uniformly increased, then strain rate is reduced, but spring characteristics are compromised
Solution Approach 1:
Instead of uniformly increasing thickness, the invention applies increased thickness locally at the upper portion of the elastic body where cracking and peeling occur. This localized approach reduces strain rate at critical areas without significantly affecting the overall spring constant and characteristics.
3Ease of manufacture
If conventional uniform thickness design is used, then manufacturing is simple, but cracking and peeling occur at upper portion under load
Solution Approach 1:
The elastic body incorporates local quality variation with different thicknesses at different portions. The upper portion has greater thickness to prevent cracking and peeling, while the lower portion maintains smaller thickness. This design balances durability requirements with manufacturing feasibility.
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 effectively prevents cracking and peeling, increasing the axle spring's durability while maintaining the necessary spring characteristics, as demonstrated by reduced strain rates and stress concentrations.
Implementation Method 1
Each of the elastic bodies 105 to 109 made of rubber are respectively fixed by vulcanization adhesion or the like between the main shaft 102 and the intermediate hard cylinder 111
Implementation Method 2
Each of the elastic bodies 105 to 109 made of rubber are respectively fixed by vulcanization adhesion or the like between the main shaft 102 and the intermediate hard cylinder 111
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An axle spring includes a main shaft arranged in a vertical direction, an outer cylinder with a tapered cylindrical shape arranged concentrically with respect to a shaft center of the main shaft in an outward radial direction of the main shaft, and an elastic portion interposed between the main shaft and the outer cylinder, the elastic portion having a laminated structure in which a plurality of elastic bodies and a plurality of intermediate hard cylinders with a tapered cylindrical shape arranged concentrically are alternately laminated in a radial direction, the plurality of elastic bodies include an innermost elastic body fixed to an outer peripheral surface of the main shaft, a thickness W1 of an upper portion of the innermost elastic body, a thickness W2 of an intermediate portion of the innermost elastic body, and a thickness W3 of a lower portion of the innermost elastic body satisfy a magnitude relationship of W1 > W3 > W2.