Shock Absorber Bypass Valve for High-Speed Damping Control
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Solution Overview
Problem
Conventional shock absorbing devices fail to reduce damping force effectively at high piston speeds, leading to inadequate suppression of vibration transfer from the axle to the vehicle body, which compromises passenger comfort.
Innovation Solution
A shock absorbing device with a bypass flow passage and a relief valve that connects the pressure chamber to the operating chambers, allowing for reduced damping force at high piston speeds by bypassing the primary flow passage resistance, thereby improving the frequency-dependent damping characteristic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a conventional shock absorbing device uses a free piston to partition the pressure chamber into one chamber and other chamber, then damping force is generated based on vibration frequency, but damping force cannot be reduced effectively at high piston speeds
Solution Approach 1:
The bypass flow passage is segmented into a first bypass flow passage connecting the other chamber to the lower chamber, and a second bypass flow passage connecting the one chamber to the upper chamber. This segmentation allows independent control of fluid flow paths, enabling the damping force to be reduced at high piston speeds while maintaining frequency-dependent damping characteristics at normal speeds.
Solution Approach 2:
The bypass flow passage acts as an intermediary flow path that provides an alternative route for liquid flow when piston speed is high. By introducing this intermediate structure, the system can bypass the restrictive orifice and free piston path, reducing damping force without compromising the frequency-based damping control at lower speeds.
2Ease of operation
If the upper chamber and lower chamber are connected via an orifice to generate frequency-dependent damping force, then passenger comfort is improved at low frequencies, but vibration transfer suppression is inadequate at high piston speeds
Solution Approach 1:
The system dynamically switches between two damping modes: at low piston speeds, the orifice and free piston provide frequency-dependent damping for passenger comfort; at high piston speeds, the bypass flow passage activates to reduce damping force and suppress vibration transfer. This dynamic adaptation resolves the contradiction between comfort and reliability.
Solution Approach 2:
The flow resistance parameter changes based on piston speed. At low speeds, the orifice provides high resistance for frequency-dependent damping. At high speeds, the bypass flow passage provides a lower resistance path, changing the overall system parameter to reduce damping force and improve vibration transfer suppression.
3Force
If the flow passage resistance in the orifice is increased to enhance low-frequency damping, then damping force is sufficient at low speeds, but flow rate through the first flow passage becomes excessive at high speeds
Solution Approach 1:
The bypass flow passage creates a parallel copy of the main flow path through the orifice and free piston. This duplicate path allows fluid to bypass the restrictive orifice at high speeds, maintaining the high-resistance characteristics for low-speed damping while providing an alternative high-flow path when needed.
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 reduces damping force at high piston speeds, enhancing passenger comfort by stabilizing the vehicle's attitude during turns and reducing vibration transfer, while maintaining adequate damping force at low frequencies.
Implementation Method 1
a relief valve is provided in the bypass flow passage
Implementation Method 2
a coil spring that biases the free piston
Implementation Method 3
a spring constant of the coil spring is set as K
Implementation Method 4
a flow rate of liquid flowing out from the upper chamber is set as Q
Data Source
AI summary
A shock absorbing device includes a cylinder. A partition wall member is inserted into the cylinder to be free to slide and partitions an interior of the cylinder into two operating chambers. A passage connects the two operating chambers. A free piston is inserted into a pressure chamber to be free to slide and partitions the pressure chamber into one chamber that communicates with one operating chamber via a one side flow passage and another chamber that communicates with the other operating chamber via another side flow passage. A spring element generates a biasing force for suppressing displacement of the free piston relative to the pressure chamber. One or both of a bypass flow passage that connects the other chamber and the one operating chamber and a bypass flow passage that connects the one chamber and the other operating chamber is provided. A relief valve is provided in the bypass flow passage.