Leaf Spring Loop Retention for Axle Safety
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Solution Overview
Problem
Conventional vehicle suspension systems with single leaf springs lack safety as they fail to maintain the vehicle axle in the longitudinal direction if the leaf spring breaks, posing serious safety concerns during vehicle operation.
Innovation Solution
A suspension system design featuring a leaf spring with a longitudinally elongated loop at the rear end that allows sliding relative to the vehicle frame, equipped with a fastener and retaining means to prevent the fastener from exiting the loop, ensuring the axle remains secured and allowing limited movement to facilitate safe stopping and parking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a single leaf spring is used for weight and cost reduction, then weight and manufacturing cost are reduced, but safety is compromised because the axle cannot be maintained in the longitudinal direction if the leaf spring breaks
Solution Approach 1:
The leaf spring is segmented into multiple leaves superimposed on each other, where at least one intermediate leaf has a breaking point with reduced cross-sectional area. This segmentation allows the intermediate leaf to break and engage the retaining member, preventing axial displacement of the axle while the other leaves continue to provide suspension function, thus maintaining safety after partial failure
Solution Approach 2:
A retaining member is pre-configured within the leaf spring structure at the breaking point location. Before any break occurs, this retaining member is positioned to receive and hold the broken end of the intermediate leaf, ensuring that when breaking occurs, the axial displacement is automatically prevented without requiring additional active components or complex mechanisms
2Reliability
If the leaf spring rear end portion forms a closed loop for secure fastening, then longitudinal maintenance is improved, but manufacturing complexity and cost increase
Solution Approach 1:
Instead of forming a completely closed loop, the leaf spring rear end portion forms a partial loop with an intentional opening. This partial loop structure provides sufficient retention for the fastener under normal operating conditions while being significantly easier to manufacture, as it avoids the complexity of forming a fully closed loop structure
Solution Approach 2:
A fastener serves as an intermediary element between the partial loop and the attachment device. The fastener is received by the partial loop and engages with the attachment device, providing the necessary connection and retention function that would otherwise require a closed loop, while allowing the simpler partial loop structure to be used
Data Source
Figure 1~2
Figure 3~7
AI summary
The invention relates to a suspension system of a vehicle axle, comprising: - a leaf spring (11); - a rear attachment device (24) which is configured to be secured to a vehicle frame (2) and which receives a rear end portion (14) of the leaf spring (11) so as to allow said leaf spring rear end portion to slide longitudinally relative to the rear attachment device; wherein: - the leaf spring rear end portion (14) forms at least part of a loop curved around a transverse axis, the loop being longitudinally elongated and having an opening (29) located at least at the front of said loop; - the rear attachment device (24) comprises a fastener (26) extending substantially transversally and received in said loop; - and the suspension system further comprises retaining means (30) configured to prevent the fastener (26) from getting out of the loop through the opening (29).