Front Fork Rod Dimple Structure for Oil Circulation and Damping
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Solution Overview
Problem
Hydraulic shock absorbers in two-wheeled vehicles face challenges in circulating sufficient oil under varying road conditions, leading to inadequate damping force on paved roads and insufficient oil circulation on unpaved roads.
Innovation Solution
The hydraulic shock absorber incorporates a rod with dimple portions recessed toward its center, allowing oil to accumulate and be carried to adjacent oil or gas chambers, thereby increasing oil circulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the hydraulic pressure is set high for unpaved roads, then damping force is sufficient on unpaved roads, but oil circulation becomes insufficient on paved roads
Solution Approach 1:
The rod is designed with a variable cross-sectional area along its length, creating different flow resistance zones. The smaller cross-sectional area portion creates higher flow resistance to generate sufficient damping force on unpaved roads, while the larger cross-sectional area portion reduces flow resistance to enable adequate oil circulation on paved roads. This dynamic geometric variation allows the system to adapt to different road conditions.
Solution Approach 2:
Different portions of the rod have different cross-sectional areas, creating localized variations in flow resistance. The smaller cross-sectional area portion is positioned to provide high resistance for damping force generation, while the larger cross-sectional area portion provides low resistance for oil circulation. This local quality differentiation resolves the contradiction between damping force and oil circulation.
2Quantity of substance
If the hydraulic pressure is set low for paved roads, then oil circulation is sufficient on paved roads, but damping force becomes insufficient on unpaved roads
Solution Approach 1:
The variable cross-sectional area of the rod dynamically adjusts flow resistance based on operating conditions. The larger cross-sectional area portion enables sufficient oil circulation on paved roads, while the smaller cross-sectional area portion ensures adequate damping force on unpaved roads. This dynamic geometric adaptation resolves the contradiction between oil circulation and damping force.
3Ease of manufacture
If the rod has a uniform cross-sectional area, then manufacturing is simple, but oil circulation is insufficient under varying road conditions
Solution Approach 1:
The rod features different cross-sectional areas at different portions along its length. The smaller cross-sectional area portion and larger cross-sectional area portion create localized flow resistance variations that enable sufficient oil circulation under varying road conditions. This local quality differentiation maintains manufacturing feasibility while improving oil circulation performance.
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 enhances oil circulation, ensuring effective damping force under various conditions, including both unpaved and paved roads.
Implementation Method 1
A part of the oil in the oil chamber enters the dimple portion. When the rod passes through the partition member in a state where the oil is accumulated in the dimple portion, the oil is carried to an adjacent oil chamber or gas chamber.
Data Source
AI summary
A front fork includes a first tube body having an oil flowing therein, a second tube body provided inside the first tube body, the second tube body having the oil flowing therein, and having the oil flowing in an oil passage formed between the first tube body and the second tube body, a partition member provided in the second tube body and partitioning one end of an oil chamber, a rod extending along an axis of the second tube body through the partition member and being configured to move relative to the partition member, an outer periphery of the rod having a dimple portion recessed toward a center of the rod, and a piston provided at a distal end of the rod and allowing the oil to pass, wherein a boundary between an outer peripheral surface of the rod and the dimple portion is formed by a curved surface.