Rotatable Leaf Spring Arrangement for Variable Stiffness
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Solution Overview
Problem
Existing vehicle suspension systems lack the ability to easily adjust and change the spring force characteristics of leaf springs, which is essential for varying load conditions and vehicle dynamics such as roll stabilization and level control.
Innovation Solution
A leaf spring design that can be rotated by 90° about its longitudinal axis, allowing for different spring rates by altering the main loading direction, and an actuator system with a self-locking worm gear for active adjustment during operation, enabling the leaf spring to be fixed in specific rotational positions for varying spring characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the leaf spring is rotated by 90° about its longitudinal axis to change spring rate, then the spring force characteristics are improved (variable spring rate achieved), but the force required for rotation must counteract the primary support force, increasing the effort needed for adjustment
Solution Approach 1:
Instead of rotating the leaf spring about its longitudinal axis (conventional approach), the invention inverts the approach by rotating the entire assembly about a vertical axis perpendicular to the leaf spring's longitudinal axis. This allows the spring to be positioned in different orientations (e.g., 0° or 90°) relative to the vehicle body, changing the spring rate without requiring force counteracting the primary support load.
Solution Approach 2:
The invention introduces an intermediary mechanism - a rotatable coupling element or pivot point - that mediates between the leaf spring and the vehicle body. This intermediary allows the leaf spring to be rotated into different positions while supporting the vehicle weight, enabling spring rate adjustment without directly counteracting the primary support force during rotation.
2Adaptability or versatility
If a motorized actuator is used to actively change spring characteristics during operation, then the adaptability is improved (active adjustment capability), but the device complexity increases
Solution Approach 1:
The invention simplifies the actuation system by inverting the rotation approach - instead of complex mechanisms to rotate the leaf spring about its longitudinal axis, a simple motorized actuator rotates the assembly about a vertical axis. This inverted approach reduces device complexity while maintaining active adjustment capability.
Solution Approach 2:
The invention changes the rotational parameter from about the longitudinal axis to about a vertical axis perpendicular to the longitudinal axis. This parameter change simplifies the actuation mechanism required, as the vertical rotation allows the leaf spring to be positioned in different orientations without complex force counteraction mechanisms.
3Adaptability or versatility
If the leaf spring arrangement allows selection between different spring characteristics, then the versatility for different load conditions is improved, but the mechanism for fixing rotational positions adds complexity
Solution Approach 1:
Instead of complex locking mechanisms to fix the leaf spring at specific rotational angles about its longitudinal axis, the invention inverts the approach by using simple angular positioning mechanisms about a vertical axis. The coupling element can be fixed at standard angles (0°, 90°, etc.) using simpler means, reducing overall mechanism complexity.
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 allows for effective and efficient adjustment of spring characteristics without counteracting the primary support force, enabling adaptable roll stiffness and vertical dynamics, influencing self-steering behavior and lateral dynamics of the vehicle.
Implementation Method 1
A leaf spring (5) which can be rotated by 90° about an axis of rotation defined by its longitudinal extent (L) is provided in the chassis of a vehicle for partial support of a body (3). If a leaf spring clamped in this way is now rotated through 90° about an axis of rotation defined by its longitudinal extension and at least in the ends of the leaf spring preferably running centrally through its cross-sectional profile, then the leaf spring in the then rotated position (or rotational position) has, with otherwise unchanged boundary conditions, in particular with the same direction of loading, of course a different spring rate or spring characteristic
Implementation Method 2
at least one actuator (10) with which the leaf spring (5) can be actively rotated and fixed in various rotational positions
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
The invention relates to an arrangement of a leaf spring (5) in the chassis of a vehicle, whose spring force characteristic acting between the vehicle body (3) and at least one wheel (1) of the vehicle can be modified, wherein the leaf spring (5) can be secured in the chassis with its ends such that it can be secured in at least two different rotational positions resulting from an at least minor rotation of the leaf spring (5) about an axis extending in the longitudinal direction thereof. On a two-track vehicle, the ends of the spring leaf (5) extending in the transverse direction of the vehicle and arranged centrally relative to the vehicle axle can each be connected via a coupling element (7) to an extension arm (6), on the other end of which a wheel (1) of the axle is supported, while the vehicle body (3) is supported on, or directly adjacent to, the coupling elements (7) on the leaf spring arrangement formed by the leaf spring (5) with the two extension arms (6). In addition, the coupling elements (7) are designed to secure the spring leaf (5) in said at least two different rotational positions on the extension arms (6), wherein an actuator (10) can be provided, by means of which the spring leaf (5) can be rotated relative to the extension arms (6) in the said manner.