Vehicle Suspension Damping Control via Stroke-Position Modulation
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Solution Overview
Problem
Existing vehicle suspension systems, such as active dampers, incur high manufacturing costs, complexity, and power consumption while offering limited control freedom.
Innovation Solution
A vehicle suspension system with a shock absorber featuring a damping force generating apparatus that adjusts damping forces based on piston stroke position, using a controller to modulate the damping force generating apparatus, allowing for increased control without additional costs or complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an active damper using hydraulic pressure or air pressure actuator is used to control damping force, then control freedom is improved, but manufacturing costs increase, mechanism becomes complicated, and power consumption increases
Solution Approach 1:
The invention extracts the thrust generation function from the damper mechanism itself and relocates it to the motor. This separates the damping control function (performed by the valve body) from the thrust generation function (performed by the motor), allowing independent optimization of each function and simplifying the overall damper structure while maintaining control freedom
Solution Approach 2:
The motor serves multiple functions: it generates thrust to apply to the valve body for damping control, and its rotation is detected to calculate piston movement amount. This multi-functionality reduces the need for separate sensors and actuators, simplifying the mechanism while preserving adaptability
2Adaptability or versatility
If an active damper using hydraulic pressure or air pressure actuator is used to control damping force, then control freedom is improved, but manufacturing costs increase
Solution Approach 1:
The invention extracts the thrust generation function from the complex hydraulic pressure or air pressure actuator and replaces it with a motor-driven mechanism. This substitution uses simpler, more cost-effective components while achieving the same control freedom through electronic control of the valve body
Solution Approach 2:
The invention replaces the mechanical hydraulic pressure actuator or air pressure actuator with an electric motor-driven system. This substitution eliminates complex mechanical linkages and pressure control mechanisms, reducing manufacturing costs while maintaining control capabilities through electronic control
3Adaptability or versatility
If an active damper using hydraulic pressure or air pressure actuator is used to control damping force, then control freedom is improved, but power consumption increases
Solution Approach 1:
The invention uses periodic pulse-width modulation (PWM) signals to control the motor, enabling efficient intermittent operation rather than continuous power consumption. The motor operates in brief pulses to achieve the required thrust, significantly reducing overall power consumption while maintaining control freedom
Solution Approach 2:
The invention changes the operational state of the motor between active (generating thrust) and inactive (coasting or braking) states, similar to switching between different modes. This dynamic state switching allows the system to achieve control freedom while minimizing power consumption by keeping the motor inactive whenever possible
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 system provides enhanced control over damping forces and spring constants, reducing resonance and improving ride comfort without increasing manufacturing costs or power consumption.
Implementation Method 1
a damping force generating apparatus which generates a damping force by controlling the flow of a working fluid generated by a sliding motion of a piston inside the cylinder
Implementation Method 2
a detector detecting a stroke position of the piston rod with respect to the cylinder
Data Source
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AI summary
A vehicle suspension system (100) includes a shock absorber (1) having a cylinder (2) in which a fluid is sealed, a piston (11) slidably fitted into the cylinder (2), a piston rod (3) connected to the piston (11) and extending to an outside of the cylinder (2) and a damping force generating apparatus (40) controlling a flow of the fluid generated by a sliding motion of the piston (11) inside the cylinder (2), a suspension spring (27), a detector (110) detecting a stroke position of the piston rod (3) with respect to the cylinder (2) and a controller (101) controlling the damping force generating apparatus (40) so that one of an extension side damping force and a compression side damping force is increased and other of them is reduced in proportion to the stroke position detected by the detector (110).