Pressurized Telescopic Fork Leg with Nested Piston and Reservoir
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Solution Overview
Problem
Pressurized front forks tend to increase in size and become expensive due to the conventional design, and they exhibit undesired hysteresis due to damping fluid movement outside the fork leg.
Innovation Solution
A pressurizing piston is arranged coaxially inside the damping fork leg, connected to a fluid reservoir outside, reducing the need for damping fluid and minimizing hysteresis by using less damping oil and integrating the fluid reservoir within the fork leg.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressurizing piston and fluid reservoir are arranged in a conventional pressurized front fork, then the damping fluid is pressurized to improve damping performance, but the front fork increases in size and becomes more expensive
Solution Approach 1:
The pressurizing piston is nested inside the inner tube of the fork leg, and the fluid reservoir is integrated into the fork leg bottom body. This nesting arrangement allows the pressurization system to be compact and integrated within the existing fork leg structure, avoiding increased overall size while maintaining pressurized damping functionality
Solution Approach 2:
The fluid reservoir is merged with the fork leg bottom body, creating an integrated structure. The pressurizing piston is combined with the inner tube assembly, allowing the pressurization function to be achieved without separate external components, thereby reducing overall size and manufacturing cost
2Ease of operation
If damping fluid channels are arranged outside the fork leg, then the damping system can function, but undesired hysteresis increases
Solution Approach 1:
The damping fluid channels are extracted from the external arrangement and moved inside the inner tube. The fluid reservoir is taken out as a separate external component and integrated into the bottom body. This extraction and repositioning eliminates the harmful hysteresis effect while maintaining damping functionality
Solution Approach 2:
The pressurizing piston acts as an intermediary element between the damping fluid and the fluid reservoir. It controls the pressurization of the damping fluid through a sealed arrangement, mediating the fluid pressure control to achieve smooth damping operation without hysteresis
3Reliability
If a conventional pressurized front fork design is used, then the damping fluid is effectively pressurized, but the manufacturing cost increases
Solution Approach 1:
The fluid reservoir is merged with the fork leg bottom body as an integrated structure, eliminating the need for separate external reservoir components. This merging reduces the number of parts, simplifies assembly, and lowers manufacturing cost while maintaining the pressurization function
Solution Approach 2:
The inner tube serves multiple functions: it houses the main piston arrangement for damping control and also contains the pressurizing piston for fluid pressurization. This multi-functionality reduces the need for separate dedicated components, simplifying the overall structure and reducing manufacturing cost
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
The solution results in a smaller, less expensive front fork with reduced hysteresis, achieved by integrating the fluid reservoir and pressurizing piston within the fork leg, allowing for self-adjustment and efficient damping fluid management.
Implementation Method 1
a pressurizing piston arranged in the inner tube and configured to pressurize the damping fluid
Implementation Method 2
The piston moves in the cylinder against the resistance of the fluid, which in turn causes damping fluid to move in the damping cylinder
Data Source
Figure 1a~1b
Figure 1c
Figure 2
AI summary
The invention relates to a telescopic fork leg for a front fork of a vehicle, comprising an outer tube and an inner tube being telescopically arranged relative each other, and a main piston arrangement arranged in the inner tube configured to regulate a damping fluid for damping movements between two parts of the vehicle when in use. Further, the telescopic fork leg comprises a pressurizing piston arranged in the inner tube and configured to pressurize the damping fluid, the pressurizing piston comprising an axial first end portion facing the main piston arrangement, and further comprising an axial opposite second end portion facing a pressurized volume. Further, the telescopic fork leg comprises a fluid reservoir for holding a pressurized fluid, the fluid reservoir being fluidly coupled to the pressurized volume. Further, the pressurizing piston is coaxially arranged with the main piston arrangement, inside the inner tube and the fluid reservoir is at least partly arranged on an outside of the inner tube. Also a front fork and a vehicle having fork legs according to above are claimed.