Front Fork Check Valve Layout for Damping Response and Noise
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing front fork designs face issues with damping force responsiveness due to restricted free piston movement and potential hydraulic fluid deficiency, leading to delayed damping force generation and noise prevention challenges.
Innovation Solution
A front fork configuration with a tubular cylinder, free piston, and check valve that allows communication between the pressure chamber and reservoir, ensuring hydraulic fluid supply and maintaining damping force responsiveness by preventing negative pressure in the contraction-side chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the free piston movement is restricted to prevent strange noise, then noise is reduced, but damping force responsiveness is degraded
Solution Approach 1:
The pressure chamber is divided into two separate chambers: the first pressure chamber between the free piston and piston that generates damping force, and the second pressure chamber between the base member and free piston that serves as a reservoir. This segmentation allows the free piston to be restricted from advancing while still enabling hydraulic fluid supply to the first pressure chamber through the second pressure chamber, thus preventing noise while maintaining damping force responsiveness.
Solution Approach 2:
The second pressure chamber acts as an intermediary reservoir that stores hydraulic fluid and supplies it to the first pressure chamber when needed. This intermediary chamber allows the system to maintain damping force responsiveness without requiring the free piston to advance, thereby preventing strange noise while ensuring adequate hydraulic fluid supply.
2Object-affected harmful factors
If the free piston is restricted from advancing, then strange noise is prevented, but negative pressure and bubbles may form in the contraction-side chamber
Solution Approach 1:
The second pressure chamber is pre-filled with hydraulic fluid and positioned to supply fluid to the first pressure chamber before the contraction stroke begins. This preliminary preparation ensures that even when the free piston is restricted from advancing, adequate hydraulic fluid is available in the first pressure chamber, preventing negative pressure and bubble formation during contraction.
Solution Approach 2:
The second pressure chamber serves as an intermediary reservoir that maintains hydraulic fluid supply stability. By decoupling the fluid supply function from the free piston movement, the system can prevent strange noise while avoiding negative pressure and bubble formation through the intermediary's continuous fluid availability.
3Temperature
If the volume of hydraulic fluid is reduced by temperature decrease, then the piston rod may retreat from the cylinder, but negative pressure and bubbles form in the contraction-side chamber
Solution Approach 1:
The second pressure chamber serves multiple functions: it acts as a reservoir for hydraulic fluid, compensates for volume changes due to temperature decreases, and supplies fluid to the first pressure chamber during contraction strokes. This multi-functionality ensures that even when hydraulic fluid volume reduces due to temperature decrease, the system maintains adequate fluid supply and prevents negative pressure and bubble formation, preserving damping force generation speed.
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 effectively maintains excellent damping force responsiveness and prevents noise by ensuring continuous hydraulic fluid supply to the pressure chamber, even under temperature changes or fluid volume reductions, thus enhancing the front fork's performance.
Implementation Method 1
a check valve provided in the passage and configured to allow only a flow of the hydraulic fluid from the reservoir to the pressure chamber
Implementation Method 2
a damping force is generated by virtue of a differential pressure between the extension-side chamber and the contraction-side chamber
Implementation Method 3
a free piston having one end connected to the piston and the other end extending outward of the cylinder... a reservoir enclosed with a hydraulic fluid and a gas
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A front fork includes a tubular cylinder (1); a free piston (2) slidably inserted into the cylinder (1) to partition the cylinder (1) into a pressure chamber (L) and a reservoir (R); a piston (3) slidably inserted into the cylinder (1) to partition the pressure chamber (L) into an extension-side chamber (L1) and a contraction-side chamber (L2); a piston rod (4) having one end connected to the piston (3) and the other end side extending oppositely to the free piston side and protruding outward of the cylinder (1); a passage (P31) configured to allow the pressure chamber (L) and the reservoir (R) to communicate with each other; and a check valve (V51) provided in the passage (P31) and configured to allow only a flow of the hydraulic fluid from the reservoir (R) to the pressure chamber (L).