Shock Absorber Bypass Valve Layout for Wider Damping Range
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Solution Overview
Problem
Existing shock absorbers face challenges in widening the adjustment range of damping force, particularly at medium- to high-speed piston speeds, leading to uncomfortable ride quality due to sudden changes in damping force characteristics when transitioning from low-speed to medium- to high-speed ranges.
Innovation Solution
A shock absorber configuration featuring a hard side damping element with an orifice and leaf valve in parallel, a solenoid valve to adjust the bypass passage aperture area, and a soft side damping element with a large-diameter orifice, allowing for continuous adjustment of damping coefficients across speed ranges, and inclusion of leaf valves in the soft side damping element to prevent excessive damping force in soft mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the valve-opening pressure of the pilot valve is lowered to reduce back pressure on the leaf valve, then the damping force becomes smaller (soft mode), but the adjustment range of damping force in medium- to high-speed range is limited and the characteristic line shifts vertically without changing slope
Solution Approach 1:
The damping element is divided into a hard side damping element (with orifice and first leaf valve) and a soft side damping element (with large-diameter orifice and second leaf valve). The solenoid valve segments the liquid flow by selectively opening bypass passages to route flow through either the hard side or soft side damping element, enabling independent adjustment of damping characteristics in different speed ranges.
Solution Approach 2:
The system dynamically switches between hard mode and soft mode by controlling the solenoid valve. In hard mode, the bypass passage is closed and liquid flows through the hard side damping element for high damping force. In soft mode, the bypass passage opens to route liquid through the soft side damping element for low damping force, enabling adaptive damping adjustment.
2Adaptability or versatility
If the characteristic line of damping force is shifted vertically by changing pilot valve pressure, then the adjustment range is widened, but the slope of the characteristic line changes suddenly during transition from low-speed to medium- to high-speed range
Solution Approach 1:
The hard side damping element is designed with specific orifice and first leaf valve characteristics optimized for medium- to high-speed ranges, while the soft side damping element uses a large-diameter orifice and second leaf valve optimized for low-speed ranges. This local optimization of each damping element's characteristics ensures smooth overall damping transitions.
Solution Approach 2:
The solenoid valve acts as an intermediary that smoothly transitions the system between hard mode and soft mode. By controlling the opening/closing of bypass passages, it enables gradual switching between different damping elements, preventing sudden changes in characteristic line slope during speed range transitions.
3Ease of operation
If a needle valve is used to adjust the aperture area of the bypass passage, then the damping force can be adjusted in low-speed range, but it is difficult to widen the adjustment range in medium- to high-speed range
Solution Approach 1:
The damping system is segmented into hard side and soft side damping elements, each with distinct orifice and leaf valve configurations. This segmentation allows independent optimization for different speed ranges, enabling wide adjustment range in medium- to high-speed range through the hard side element while maintaining low-speed adjustability through the soft side element.
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 configuration enables a wider adjustment range of damping force, ensuring a more gradual transition of damping force characteristics from orifice to valve characteristics, thereby improving ride quality by reducing discomfort caused by sudden changes in damping force slopes.
Implementation Method 1
a solenoid valve configured to change the aperture area of a bypass passage that bypasses the hard side damping element and communicates with the extension side chamber and the compression side chamber
Implementation Method 2
a resistance is imparted by a damping element to a liquid flow produced when a piston moves inside the cylinder, and a damping force caused by the resistance is exhibited
Data Source
AI summary
A shock absorber includes a hard side damping element that imparts a resistance to a flow of liquid moving between an extension side chamber and a compression side chamber, a solenoid valve configured to change an aperture area of a bypass passage that bypasses the hard side damping element and communicates with the extension side chamber and the compression side chamber, a soft side damping element provided in series with the solenoid valve in the bypass passage, and a tank connected to the compression side chamber. The hard side damping element includes an orifice and leaf valves provided in parallel with the orifice. The soft side damping element includes an orifice having a larger aperture area than the orifice.