Shock Absorber Fail-Safe Valve for Damping Stability
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Solution Overview
Problem
Existing shock absorbers with fail-safe valves do not maintain stability in damping force at failure times due to sudden changes in solenoid operation, leading to instability in vehicle operation.
Innovation Solution
A shock absorber design incorporating a fail-safe valve mechanism with a dual function of fail-safe and check valve, utilizing a combination of elastic bodies to control fluid flow, ensuring stability by preventing sudden changes in damping force during solenoid failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a control valve with solenoid actuator is used to adjust damping force, then damping force control capability is improved, but reliability deteriorates due to solenoid failure causing sudden damping force change
Solution Approach 1:
The fail-safe valve is pre-configured to close the pilot channel automatically when the solenoid fails, preventing the sudden pressure drop that would otherwise occur. This beforehand preparation ensures that when failure happens, the system transitions to a safe state rather than an unstable state.
Solution Approach 2:
The fail-safe valve acts as an intermediary component between the solenoid control system and the main damping force control mechanism. It mediates the transition by controlling the pilot channel that regulates pilot chamber pressure, thereby preventing direct and sudden changes in main valve opening when solenoid failure occurs.
2Reliability
If a fail-safe valve is added to prevent sudden damping force change, then reliability is improved, but device complexity increases
Solution Approach 1:
The fail-safe valve is designed to perform multiple functions: it serves as both a fail-safe mechanism that closes the pilot channel upon solenoid failure, and as part of the normal damping force adjustment system during operational conditions. This multi-functionality reduces the need for entirely separate safety systems.
Solution Approach 2:
The fail-safe valve mechanism is merged with the existing pilot channel and pilot chamber pressure control system. Rather than creating a completely independent safety system, the fail-safe valve integrates into the current hydraulic control architecture, sharing common components like the pilot channel and pressure regulation mechanisms.
3Ease of operation
If the pilot channel is always open for normal operation, then ease of operation is improved, but harmful factors increase due to fluid backflow causing damping force variation
Solution Approach 1:
The fail-safe valve transitions from a static always-open state during normal operation to a dynamically closed state upon solenoid failure. This dynamic behavior allows the system to adapt its flow control characteristics based on operational conditions, maintaining ease of operation when needed while preventing harmful backflow when necessary.
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 dual-function fail-safe and check valve mechanism maintains consistent damping force stability at both normal and failure times, enhancing vehicle operation stability by preventing sudden fluid backflow and adjusting damping force characteristics.
Implementation Method 1
the fail-safe valve is urged by a first elastic body in the valve closing direction of the valve body
Implementation Method 2
an actuator that moves the valve body in a valve closing direction with thrust of a solenoid
Implementation Method 3
when the fluid flows in the valve opening direction of the valve body, the fail-safe valve is spaced from the valve body by a fluid pressure to open the channel
Data Source
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AI summary
A shock absorber includes: a valve body; a valve seat; an actuator; and a fail-safe valve that is urged by a first elastic body. When fluid does not flow, the fail-safe valve is urged by the first elastic body to come into contact with the valve body and close a channel. When the fluid flows, the fail-safe valve is spaced from the valve body by a fluid pressure to open the channel. When the valve body moves most in a valve opening direction, the fail-safe valve is brought into contact with the valve body and the channel is closed, and a supporting portion supports a part of the fail-safe valve. When the fluid flows in this state, at least a part of the fail-safe valve, which is in contact with a non-supporting portion, is spaced from the valve body by the fluid pressure to open the channel.