Variable-Stiffness Spring Unit to Prevent Suspension Bottoming Out
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Solution Overview
Problem
Existing marine and land vehicle suspensions, such as those in high-speed boats and vehicles traversing uneven terrain, suffer from issues like bottoming out, amplifying impacts, and requiring excessive space and weight, posing safety risks and inefficiencies.
Innovation Solution
A spring unit with a flexible member and engagement element that adjusts the spring constant in response to load, increasing stiffness upon contact to mitigate larger impacts while maintaining ease of installation and adaptability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid spring structure is used to mitigate large impacts, then shock mitigation for large impacts is improved, but the suspension bottoms out and amplifies impacts on the occupant
Solution Approach 1:
The spring constant is made dynamically adjustable through the engagement element mechanism. When the second attachment arrangement moves within the normal range (0 to d1), the first flexible member maintains a first spring constant for comfort. When movement exceeds d1, the flexible member contacts the engagement element and transitions to a second spring constant for large impact mitigation, preventing bottoming out while maintaining safety
Solution Approach 2:
The spring constant parameter is changed based on the magnitude of impact. The system transitions between two spring constant values (first spring constant for small impacts, second spring constant for large impacts) using the engagement element mechanism, allowing the suspension to adapt its stiffness parameter to the current loading condition
2Strength
If a complex suspension mechanism is used to provide adjustable spring rates, then shock mitigation is improved, but device complexity and space requirements increase
Solution Approach 1:
The engagement element mechanism operates automatically based on the position of the second attachment arrangement. The system self-adjusts the spring constant by detecting when the flexible member contacts the engagement element, eliminating the need for external control systems, sensors, or actuators, thereby reducing device complexity while maintaining adjustable spring rate capability
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 spring unit effectively reduces the risk of bottoming out and enhances shock mitigation for both small and large impacts, providing improved safety and space efficiency.
Implementation Method 1
a first flexible member (5) attached to and extending between the first attachment arrangement (2) and the second attachment arrangement (3)... arranged to move a first distance (L1) essentially vertically in response to a load being exerted on the second attachment arrangement (3)
Implementation Method 2
a first engagement element (7) arranged to cause a change in a spring constant of the first flexible member (5)... when the second attachment arrangement (3) has moved a part of the first distance (L1), the first flexible member (5) comes into contact with the first engagement element (7), leading to that the spring constant of the first flexible member (5) increases
Data Source
Figure 1
Figure 2a
Figure 2b
AI summary
The disclosure relates to a spring unit (1) and a method for changing a spring constant of a spring arrangement (4) in a spring unit (1). The spring unit (1) comprises a first attachment arrangement (2), a second attachment arrangement (3) and a spring arrangement (4). The spring arrangement (4) comprises a first flexible member (5) attached to and extending between the first attachment arrangement (2) and the second attachment arrangement (3). The first attachment arrangement (2) is fixedly attached to a support structure (6) and the second attachment arrangement (3) is arranged to move a first distance (L_1) essentially vertically in response to a load being exerted on the second attachment arrangement (3). The spring arrangement (4) further comprises a first engagement element (7) arranged to cause a change in a spring constant of the first flexible member (5), such that the spring constant of the first flexible member (5) increases after the second attachment arrangement (3) has moved a part of the first distance (L_1).