Front Fork Cap Structure for Longer Suspension Spring Travel
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Solution Overview
Problem
Conventional front forks have a cap formed by two parts connected by thread fastening, leading to a longer cylindrical member and a downward shift in the support position of the suspension spring, which reduces the storage length and design freedom of the suspension spring.
Innovation Solution
A front fork configuration with a cap formed by a single part, featuring a cylindrical portion with an annular lid and a washer with an arm portion that supports the suspension spring, allowing the opening for the arm portion to be positioned upward, thereby shortening the cap length and increasing the storage length of the suspension spring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the cap is formed by two parts connected by thread fastening, then the cap can be assembled and disassembled easily, but the cylindrical member becomes longer and the support position of the suspension spring shifts downward
Solution Approach 1:
The patent merges the lid portion and cylindrical portion into a single integrated cap structure. The lid portion forms the upper end closure while the cylindrical portion forms the main body, eliminating the need for thread fastening connection between separate parts. This integration directly reduces the cap length by removing the overlap margin required for threaded connections.
2Stability of the object's composition
If the cap is formed by two parts with thread fastening, then the structure is stable, but the storage length of the suspension spring is reduced
Solution Approach 1:
By integrating the lid portion and cylindrical portion into a single cap, the patent eliminates the downward shift in spring support position that occurs with two-part constructions. The arm portion supporting the spring can be positioned higher on the cylindrical portion, maximizing the storage length available for the suspension spring while maintaining structural integrity through the unified design.
3Ease of manufacture
If the opening for the arm portion is positioned downward to avoid the screw portion, then the cap length increases, but the spring support position shifts downward
Solution Approach 1:
The patent repositions the opening from a downward position to an upward position on the cylindrical portion. This dimensional repositioning allows the arm portion to extend upward to support the spring, eliminating the need for the opening to be located downward to avoid interference with screw portions. The integrated cap design provides sufficient length to accommodate both the upward opening and any necessary fastening features.
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 configuration enhances the design freedom and storage length of the suspension spring, allowing for improved adjustment and reduced weight of the front fork, while preventing the adjuster from detaching and maintaining smooth operation.
Implementation Method 1
a suspension spring 4 that biases the tube member 3 in a stretching direction
Implementation Method 2
is rotatable in a circumferential direction with respect to the cap 5
Data Source
AI summary
A front fork (1) includes: a fork main body (2) that includes a tube member (3) including a vehicle body side tube (3a) and an axle side tube (3b), and a suspension spring (4) that biases the tube member (3) in a stretching direction; a cap (5) that includes a cylindrical portion (5a) and a lid portion (5b) continuing to the outer circumference of the cylindrical portion (5a), and closes the opening end of the vehicle body side tube (3a); a washer (6) that supports the upper end of the suspension spring (4); an adjuster (7) that includes a shaft portion (7a) screwed to the washer (6), a flange portion (7b) provided at the rear end of the shaft portion (7a), and an operation shaft portion 7c extending from an opposite shaft portion side of the flange portion (7b), and that is rotatably inserted into the cylindrical portion 5a; and a stopper member (8) that is placed on the inner circumference of the cylindrical portion (5a) and prevents the adjuster (7) from being detached from the cap (5).