Dual-Rate Leaf Spring Suspension with Deformable Stop Elements
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Solution Overview
Problem
Existing two-stage suspension systems for vehicle axles are bulky and heavy due to the need for additional springs and connecting components, which increases unsprung mass and constructional space, making them inefficient in terms of dynamics and space usage.
Innovation Solution
A compact axle suspension design featuring a longitudinal leaf spring with a concave shape and a connecting arm, where a first stop element on the connecting arm and a second stop element on the vehicle structure are initially spaced apart, but come into contact and deform elastically when a limit load is exceeded, providing a dual-rate suspension with increased stiffness without the need for additional springs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a secondary spring is added to create a two-stage suspension system, then the spring constant can be increased above a limit load, but the mass of the spring assembly increases
Solution Approach 1:
The patent changes the geometric parameters of a single leaf spring (thickness variation along its length) to achieve dual-rate suspension characteristics. The spring has a first region with greater thickness for high load support and a second region with lesser thickness for normal operation, eliminating the need for a separate secondary spring and reducing overall mass.
Solution Approach 2:
The patent combines the functions of primary and secondary springs into a single integrated leaf spring structure. The varying thickness profile of the spring integrates both the soft suspension characteristics for normal loads and the stiff support characteristics for high loads, merging what would traditionally require two separate components.
2Force
If multiple springs are arranged in a spring assembly, then dual-rate suspension is achieved, but the constructional space required increases
Solution Approach 1:
The patent merges multiple spring functions into a single leaf spring with variable thickness. This integration eliminates the need for separate primary and secondary springs, reducing the constructional space required while maintaining the dual-rate suspension capability through the spring's geometric design.
Solution Approach 2:
By varying the thickness parameter along the length of the leaf spring, the patent achieves dual-rate suspension characteristics in a single component. This parameter change allows the spring to provide different stiffness levels at different regions, eliminating the need for multiple springs and reducing the space they would occupy.
3Volume of moving object
If the primary spring is designed to handle all loads, then constructional space is reduced, but the spring constant cannot be increased above a limit load
Solution Approach 1:
The patent applies parameter changes by varying the thickness of the leaf spring along its length. The first region has greater thickness to provide high spring constant for limit loads, while the second region has lesser thickness for normal operation. This allows a single spring to provide both low and high spring constant characteristics at different locations.
Solution Approach 2:
The patent applies local quality by giving different thicknesses to different regions of the leaf spring. The first region (for high load) has greater thickness and stiffness, while the second region (for normal operation) has lesser thickness. This local variation in properties allows the spring to handle different load conditions effectively within a single component.
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 enhances vehicle handling and comfort by adapting to higher loads with increased stiffness, prevents axle collision with the vehicle structure, and reduces unsprung mass and constructional space, resulting in a more efficient and compact suspension system.
Implementation Method 1
at least one stop element is elastically deformable when contacted by the other stop element
Data Source
AI summary
An axle suspension for a vehicle includes a spring assembly with a leaf spring and a connecting arm, wherein the leaf spring supports a vehicle axle and, on an end side, is pivotably connected to a vehicle structure and pivotably connected to the connecting arm. In order to provide an optimized axle suspension with two-stage suspension, the spring assembly in a region of the connecting arm has a first stop element and the vehicle structure has a second stop element, which stop elements under normal load of the vehicle are spaced apart from one another and, when a limit load is exceeded, contact one another, whereby at least one stop element is elastically deformable.