Air Spring Ribs for Flatness and Shape Flexibility
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Solution Overview
Problem
Conventional air spring devices have limited shape flexibility and spring characteristic adjustment due to their flat plate structure, which restricts their ability to effectively contact and adapt to varying attachment surfaces in railway vehicles.
Innovation Solution
The air spring device features a tubular flexible diaphragm coupling an upper and lower face plate with ribs that rise from the upper face plate, allowing the top portions of the ribs to lie in the same plane for enhanced flatness and increased shape flexibility, while the ribs improve strength and control spring characteristics without increasing mass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the upper face plate is designed with a flat plate structure corresponding to the attachment surface, then the flatness of the upper face plate is ensured, but the degree of freedom of the shape is reduced
Solution Approach 1:
The upper face plate is segmented into a flat linear portion and a sloping portion with ribs. The flat linear portion ensures contact flatness with the attachment surface, while the sloping portion with variable ribs provides shape flexibility for spring characteristic adjustment. This segmentation allows different regions to fulfill different functions simultaneously.
Solution Approach 2:
Different regions of the upper face plate are given different geometric properties: the linear portion maintains flatness for reliable contact, while the sloping portion incorporates ribs with varying shapes, positions, and configurations to locally adjust spring characteristics. This local differentiation enables both flatness requirement and shape flexibility.
2Adaptability or versatility
If the shape of the upper face plate is changed to adjust spring characteristics, then the degree of freedom of shape is increased, but the flatness of the upper face plate is compromised
Solution Approach 1:
The upper face plate is divided into a flat linear portion for contact and a sloping portion for spring characteristic adjustment. This segmentation isolates the flatness requirement to the linear portion while allowing shape variation in the sloping portion, thereby adjusting spring characteristics without compromising contact flatness.
Solution Approach 2:
The design transitions from a two-dimensional flat plate to a three-dimensional structure with ribs extending vertically from the sloping portion. This dimensional change allows spring characteristic control through rib geometry while the top surfaces of the ribs maintain a common plane, preserving the effective flat contact surface.
3Strength
If ribs are added to improve the strength of the upper face plate, then the strength is improved, but the mass of the upper face plate increases
Solution Approach 1:
Ribs are strategically positioned in the sloping portion of the upper face plate where structural reinforcement is most needed. The ribs have varying cross-sections and spacing optimized for local stress distribution, providing maximum strength enhancement with minimum material addition, thereby limiting mass increase.
Solution Approach 2:
The sloping portion with ribs creates a curved, three-dimensional structure that distributes mechanical loads more efficiently than a flat plate. This curvature provides inherent structural strength and stiffness, reducing the need for additional material and limiting mass increase while improving overall strength.
4Strength
If the upper face plate is made thicker to ensure flatness and strength, then the flatness and strength are improved, but the mass of the upper face plate increases
Solution Approach 1:
The upper face plate is segmented into regions with different thicknesses and geometries. The linear portion maintains adequate thickness for flatness, while the sloping portion uses rib structures to provide localized reinforcement. This segmentation achieves required flatness and strength without uniformly increasing thickness and associated mass.
Solution Approach 2:
The design utilizes a thin-walled structure with strategic rib reinforcement rather than a uniformly thick plate. The ribbed sloping portion provides structural integrity and flatness where needed while minimizing material usage, effectively reducing mass compared to a uniformly thick design.
Data Source
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AI summary
An air spring device (10) has: an air spring (12) in which an upper face plate (16) and a lower face plate (18) are airtightly coupled to each other by a tubular flexible diaphragm (22); and ribs (14) (projecting portions) that rise from an upper surface of the upper face plate (16) and have top portions (14A) that lie in the same plane as each other.