Motorcycle Leaf Spring Suspension With Offset Pivot Levers
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Solution Overview
Problem
Leaf springs in motorcycles require large installation space, are complex, reduce ground clearance, and have a short service life due to exposure and delamination issues, limiting their use in series production.
Innovation Solution
A leaf spring concept that connects to the frame via a first lever and pivot bearing, and to the swingarm via a second lever and pivot bearing, allowing transverse offset pivots to provide an additional degree of freedom, reducing installation space and enabling precise control of spring force progression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If leaf spring is used as 3-point bending beam, then spring effect is achieved, but installation space requirement increases
Solution Approach 1:
The patent transitions from a traditional 3-point bending beam configuration to a 4-point bending configuration by adding a second support point on the swingarm. This dimensional change in the support structure allows the leaf spring to achieve the necessary spring effect with reduced installation space requirements, as the additional support point distributes the mechanical load more efficiently across the suspension system.
Solution Approach 2:
The patent introduces lever mechanisms as intermediary elements between the leaf spring and the frame/swingarm. These levers act as mediators that transmit and transform the forces, allowing the leaf spring to function effectively while requiring less installation space. The lever arms provide mechanical advantage and enable the compact arrangement of components.
2Ease of manufacture
If leaf spring is arranged in exposed places, then installation is simplified, but service life decreases due to delamination
Solution Approach 1:
The patent addresses the vulnerability of exposed leaf springs to stone chippings and ground contact by designing a suspension geometry where the leaf spring operates in a more protected position. The swingarm and other components naturally shield the leaf spring from direct exposure to harmful external factors, converting the previously harmful exposed position into a more protected configuration without sacrificing installation simplicity.
3Strength
If leaf spring is used to achieve desired spring progression, then additional component parts are required, but device complexity increases
Solution Approach 1:
The patent makes the leaf spring itself multi-functional by configuring it with both support points on the frame and swingarm. This universal configuration allows the single leaf spring component to simultaneously provide the spring effect and the desired progressivity through its geometric arrangement and bending characteristics, eliminating the need for separate progressive spring mechanisms or additional component parts.
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 achieves a compact, durable, and lightweight suspension with improved riding properties by minimizing installation space, maintaining ground clearance, and allowing independent damping and kinematics settings, suitable for series-production motorcycles.
Implementation Method 1
a leaf spring (4), which connects a swingarm (3) and a frame (2) of the single-track vehicle (1) and has a first end (7) and a second end (8)
Data Source
AI summary
A single-track vehicle, in particular a motorcycle, includes a frame, a rocker rotatable relative to the frame, and a leaf spring connected to the frame and to the rocker to achieve a spring effect between the rocker and the frame. The leaf spring is connected to the frame via a first lever and a first rotary bearing such that a first rotational axis of the first rotary bearing is transversely offset relative to the leaf spring as a result of the first lever. Alternatively or in addition, the leaf spring is connected to the rocker via a second lever and a second rotary bearing such that a second rotational axis of the second rotary bearing is transversely offset relative to the leaf spring as a result of the second lever.