Hydraulic Bicycle Suspension With Switchable Stiffness Control
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Solution Overview
Problem
Racing bicycles require a suspension system that can dynamically switch between a stiff and elastic structure to adapt to varying terrain conditions, as existing adjustable suspensions are either too stiff for smooth riding or too soft for uneven terrain, failing to effectively absorb vibrations.
Innovation Solution
A suspension system incorporating an elastic element and a hydraulic circuit with a double-acting piston and an electrically actuated valve, allowing the system to transition between a stiff and elastic mode by controlling fluid flow within the circuit, connected between the bicycle frame and fork, enabling the cyclist to manually or automatically adjust the stiffness based on terrain conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an adjustable damper is provided in the suspension, then the stiffness can be adapted to terrain conditions, but the device complexity increases
Solution Approach 1:
The suspension system transitions from a static stiffness configuration to a dynamic one by using a controllable valve to regulate hydraulic fluid flow. The valve can be actuated in real-time to adjust the damper's resistance, allowing the suspension to adapt its stiffness characteristics according to terrain conditions while maintaining a relatively simple mechanical structure.
Solution Approach 2:
The patent employs a hydraulic circuit with fluid flowing through passages in the damper body. By controlling the valve that regulates fluid flow between chambers, the system achieves adjustable damping characteristics without requiring complex mechanical linkages or multiple dampers. The hydraulic mechanism provides smooth stiffness variation with compact construction.
2Strength
If the suspension is made stiff for smooth terrain, then structural integrity is maintained, but vibration absorption capability is reduced
Solution Approach 1:
The suspension system changes the damping parameter dynamically by adjusting valve opening degree. On smooth terrain, the valve closes to increase damping force and maintain structural integrity. On uneven terrain, the valve opens to decrease damping force and absorb vibrations, thus adapting the suspension's mechanical properties to different operational conditions without compromising structural strength.
Solution Approach 2:
The damper transitions from a fixed-stiffness design to a dynamic stiffness system where the damping coefficient can be continuously adjusted. This allows the suspension to be stiff when needed for structural support and compliant when needed for vibration absorption, resolving the contradiction between strength and vibration resistance.
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 solution allows for seamless adaptation of the bicycle's stiffness to terrain conditions, enhancing comfort by absorbing vibrations while maintaining structural simplicity and allowing for manual or automatic control, thereby improving the overall riding experience.
Implementation Method 1
a closed hydraulic circuit (4) containing a working fluid (5)... a hydraulic cylinder-piston group (60), comprising a cylinder (10) and a hydraulic piston (6), movable inside the cylinder (10)... immersed in the working fluid (5)
Implementation Method 2
an elastic element (2), which is for example a coil spring or an elastic body of a different type
Data Source
Figure 1~2
Figure 3
AI summary
A suspension (1) for a bicycle (101) comprising an elastic element (2) and a blocking/releasing device (3) of the elastic element (2). The blocking/releasing device (3) comprises: - a closed hydraulic circuit (4) containing a working fluid (5); - a cylinder-piston assembly (60) comprising a cylinder (10) and a piston (6) slidable inside said cylinder, said cylinder-piston assembly (60) being inserted in the hydraulic circuit (4) and being operatively disposed in parallel with said elastic element; - a valve (8) commanded by an actuator (9) inserted in the hydraulic circuit (4) and configurable according to an open configuration, so that the working fluid (5) freely flows in the hydraulic circuit for enabling movements of the piston (6) inside the cylinder (10), and a closed configuration, so that the working fluid (5) is prevented from flowing in the hydraulic circuit (4) and the piston (6) is kept blocked by the working fluid (5); - a main housing (11) receiving inside the cylinder-piston assembly (60); wherein the hydraulic circuit (4) is made in a space formed between the walls of the main housing (11) and the walls of the cylinder (10).