Motorcycle Leaf Spring Suspension via Offset Pivot Levers
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Solution Overview
Problem
Leaf springs in motorcycles require significant installation space, are complex, reduce ground clearance, and have a short service life due to exposure and delamination issues, limiting their use in mass production.
Innovation Solution
A leaf spring design connected via levers and pivot bearings offset transversely to the frame and swingarm, allowing for two-point attachment, which provides an additional degree of freedom for suspension kinematics and spring force progression control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If leaf spring is used as three-point bending beam with multiple attachment points, then suspension effect is achieved, but installation space requirement increases significantly
Solution Approach 1:
The patent transitions from a planar three-point bending beam configuration to a spatial arrangement using levers with transverse offset pivot axes. This dimensional change allows the leaf spring to achieve suspension functionality with fewer attachment points, reducing installation space requirements while maintaining structural integrity and suspension effect.
Solution Approach 2:
The patent divides the connection system into separate components: the leaf spring, levers, and pivot bearings. This segmentation allows each component to perform its specific function efficiently, with the levers providing mechanical advantage and the pivot bearings enabling rotation, thereby achieving suspension effect with minimal attachment points.
2Reliability
If multiple components are used to achieve desired spring force progression, then suspension performance is improved, but device complexity increases
Solution Approach 1:
The levers in the patent serve multiple functions simultaneously: they provide mechanical advantage for spring force progression, act as structural connectors between the leaf spring and frame, and enable rotational movement through pivot bearings. This multi-functionality achieves desired suspension performance without increasing component count.
Solution Approach 2:
The patent combines the functions of spring force application, mechanical advantage, and rotational movement into an integrated lever-pivot bearing-leaf spring system. This merging of functions reduces the number of separate components needed while maintaining or improving spring force progression characteristics.
3Ease of manufacture
If leaf spring is positioned in exposed locations for installation, then assembly is simplified, but service life decreases due to impacts and delamination
Solution Approach 1:
The levers act as intermediary components between the leaf spring and the frame, allowing the leaf spring to be positioned in more protected locations. The levers transmit forces and accommodate movements while shielding the leaf spring from direct impacts by stones and ground contact, thereby extending service life without significantly complicating assembly.
4Area of stationary object
If leaf spring positioning is constrained by geometric arrangement, then installation space is reduced, but design flexibility for spring force progression is limited
Solution Approach 1:
The patent introduces dynamic elements through the levers with transverse offset pivot axes, allowing the system to adapt its geometry during operation. This dynamic configuration enables the leaf spring to maintain compact installation while achieving desired spring force progression through the lever mechanical advantage, providing both space efficiency and design flexibility.
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 minimizes installation space, maintains ground clearance, reduces weight, and enhances durability by evenly distributing load, while allowing independent adjustment of damping and spring rate, suitable for series production motorcycles.
Implementation Method 1
a leaf spring (4) which is connected to the frame (2) on one side and the swing arm (3) on the other side to achieve a spring effect between the swing arm and the frame
Implementation Method 2
the leaf spring is connected to the frame via a first lever (5.1) and a first pivot bearing (6.1), such that a first axis of rotation of the first pivot bearing is offset transversely to the leaf spring due to the first lever
Data Source
Figure 1~2b
Figure 3a~3b
Figure 4~5
AI summary
The invention relates to a single-track vehicle, in particular a motorcycle, comprising: - a frame (2), - a rocker (3) which can be rotated relative to the frame (2), and - a leaf spring (4) which is connected to the frame (2) and to the rocker (3) in order to achieve a spring effect between the rocker (3) and the frame (2), wherein - the leaf spring (4) is connected to the frame (2) via a first lever (5.1) and a first rotary bearing (6.1) such that a first rotational axis of the first rotary bearing (6.1) is transversely offset relative to the leaf spring (4) as a result of the first lever (5.1) and/or - the leaf spring (4) is connected to the rocker (3) via a second lever (5.2) and a second rotary bearing (6.2) such that a second rotational axis of the second rotary bearing (6.2) is transversely offset relative to the leaf spring (4) as a result of the second lever (5.2).