Front Fork Suspension Layout for Motorcycle Swing Arm Interference
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Solution Overview
Problem
Existing front wheel suspension devices for saddle-ride type vehicles face interference issues between the swing arm and front fork, making it difficult to ensure the length and flexibility of the swing arm due to the radial support of the front fork outside the supporting member.
Innovation Solution
A front wheel suspension device with a cylindrical supporting member that internally supports the front fork, allowing it to rotate about a steering axis, while the link member and swing arm are designed to be rockably connected, offsetting the steering and rotational axes to reduce interference and enhance layout flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the front fork is supported on the outside in the radial direction of the supporting member, then the front fork can be rotatably supported, but the swing arm and front fork become likely to interfere with each other, making it difficult to layout the swing arm
Solution Approach 1:
The patent inverts the conventional support arrangement by moving the front fork from the outside of the supporting member to the inside. This spatial inversion resolves the interference problem between the swing arm and front fork, allowing the swing arm to be laid out without obstruction while maintaining the rotational support function of the front fork.
2Device complexity
If the swing arm is disposed at a position rearwardly of the supporting member or overlapping the central axis, then the supporting structure is simplified, but it is difficult to ensure the length of the swing arm
Solution Approach 1:
The patent resolves the contradiction by changing the spatial arrangement from a rearward/displaced position to a position overlapping the central axis of the supporting member. This dimensional repositioning allows the swing arm to achieve sufficient length for proper suspension geometry while maintaining a simple supporting structure through the centralized arrangement.
3Ease of operation
If the steering axis and rotational axis are offset longitudinally, then the link member layout is improved, but the handlebar height increases
Solution Approach 1:
The patent applies parameter changes by adjusting the longitudinal offset distance between the steering axis and rotational axis to an optimized value. This parameter optimization achieves improved link member layout while controlling the handlebar height increase to an acceptable level, balancing geometric requirements with ergonomic constraints.
Data Source
AI summary
A front wheel suspension device for a saddle-ride type vehicle, includes a front fork for supporting a front wheel with a steering member that is rotated about a rotational axis in accordance with operation of a handlebar. A link member is composed of an upper link rockably connected to the steering member and a lower link rockably connected to the upper link and the front fork. A swing arm includes upper and lower arms. A supporting member forms a steering axis and rockably supports front ends of the upper and lower arms. The supporting member is of a cylindrical shape, and supports the front fork on the inside in the radial direction of the supporting member such that the front fork is rotatable about the steering axis. The length of the swing arm is ensured while increasing flexibility in the layout of the swing arm.