Variable Spring Characteristic Motor Vehicle Suspension
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Solution Overview
Problem
Existing spring devices for motor vehicles, such as those used in motorcycles, face issues with maintaining optimal handling characteristics under varying loads, as they either have a constant spring characteristic that results in excessive travel during increased loads or abrupt transitions in stiffness, leading to dangerous handling situations.
Innovation Solution
A spring device with a load-dependent, variable spring characteristic is designed, featuring a first compression spring made of elastomeric material with a progressively increasing spring characteristic, and a second spiral spring in series, along with adjustable blocking means to control spring travel, ensuring the spring travel remains short under high loads and providing improved handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a linear spring characteristic is used with adjustable preload, then ride height can be adjusted to load weight, but the spring constant remains too low under high load causing excessive spring travel
Solution Approach 1:
The spring characteristic is changed from static (linear) to dynamic (progressive), where the spring constant automatically increases with load. This allows the spring to provide appropriate stiffness for different loading conditions without manual adjustment, resolving the contradiction between ease of operation and reliability under load.
Solution Approach 2:
The spring parameter (spring constant) is changed from constant to variable based on load conditions. The progressive spring characteristic ensures that the spring constant increases as the load increases, maintaining optimal handling characteristics across different loading scenarios.
2Reliability
If multiple spiral springs are used in series with blocking mechanism, then spring stiffness can be increased under load, but the abrupt transition causes dangerous handling situations
Solution Approach 1:
Instead of abrupt parameter changes through blocking mechanisms, the patent uses a progressive spring characteristic where the spring constant increases gradually and continuously with compression. This eliminates harmful abrupt transitions while maintaining increased stiffness under load.
Solution Approach 2:
The patent converts the potential harm of abrupt stiffness changes into a benefit by designing a progressive spring that provides smooth, continuous stiffness increase. This transforms what could be a dangerous abrupt transition into a beneficial gradual adaptation to load conditions.
3Reliability
If a compression spring with progressively increasing spring characteristic is used, then the spring travel remains short under high load, but the spring device complexity increases
Solution Approach 1:
The patent uses composite construction within the spring element, combining different materials or structural features to achieve the progressive spring characteristic. This allows the complex spring behavior to be achieved through material composition rather than complex mechanical mechanisms.
Solution Approach 2:
Different parts of the spring have different local properties that contribute to the overall progressive characteristic. For example, varying wire diameter, spring index, or material properties along the spring length creates the desired non-linear behavior without requiring a complex multi-component system.
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
The solution ensures optimal handling characteristics by automatically adjusting the spring behavior to load conditions, preventing excessive travel and abrupt transitions, thus enhancing safety and ride quality, particularly when carrying passengers or luggage.
Implementation Method 1
a first compression spring (410) made of elastomeric material with a progressively increasing spring characteristic
Data Source
Figure 1
Figure 6~8
AI summary
A spring device for a motor vehicle, comprising a damper system with a damper cylinder (102), and a damper piston movable in said damper cylinder, and a spring element comprising at least a first compression spring (110), which in particular is fitted coaxially relative to the damper system, in which the first compression spring (110) is confined between a first and a second spring base (106). The first compression spring (110) has a spring characteristic whose value is at least partially dependent upon the magnitude of the load upon the first compression spring.