Self-Adjusting Hydraulic End Stop for Load-Adaptive Shock Absorbers
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Solution Overview
Problem
The existing hydraulic shock absorbers with end stops face difficulties in adjustment and replenishment, leading to cavitation issues due to a single control chamber, which affects the braking force curve and comfort levels in vehicles, especially when loaded.
Innovation Solution
A telescopic hydraulic shock absorber with a sliding main axis, featuring a damping piston, a sleeve, and a valve with separate chambers that allow for precise adjustment of the braking force curve by varying the fluid passage through calibrated bores, providing flexibility for lightly loaded vehicles and stiffness for heavily loaded ones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single control chamber is used in the slide, then the structure is simpler, but adjustment difficulty and cavitation problems increase
Solution Approach 1:
The single control chamber is divided into two separate chambers (first control chamber and second control chamber) separated by a slide piston. This segmentation allows independent control of fluid flow in different directions, enabling precise adjustment of the braking force curve while eliminating cavitation issues. The first chamber handles fluid flow during suspension compression while the second chamber manages fluid flow during rebound, providing optimized performance for each phase.
2Reliability
If the slide valve is forced down by frequent thrust spring pressure, then safety under load is improved, but comfort during light loading deteriorates
Solution Approach 1:
The slide valve is made dynamically adjustable through the two-chamber system with calibrated bores. During light loading, the calibrated bores in the first chamber allow controlled fluid flow that maintains comfort while preventing excessive valve descent. During heavy loading, the thrust spring can force the valve down further to close the bores, providing the necessary stiffness and safety. This dynamic adaptability resolves the contradiction between comfort and safety.
Solution Approach 2:
The system changes the flow parameters through calibrated bores of different sizes in the two chambers. The first chamber has calibrated bores that control fluid flow during normal operation to maintain comfort, while the second chamber provides additional flow control during extreme conditions. This parameter variation allows the system to adapt between comfort-oriented and safety-oriented operating modes.
3Reliability
If holes in the stop tube are closed to stiffen the end stop, then safety under load is improved, but flexibility for light loading is reduced
Solution Approach 1:
The fluid flow control is segmented into multiple pathways: the first control chamber with calibrated bores for normal operation, the second control chamber for additional flow control, and the ability to close off pathways under extreme conditions. This segmentation allows the system to maintain flexibility during light loading through the calibrated bores while providing the option to stiffen under heavy load by forcing the slide down to close the bores.
Solution Approach 2:
The two-chamber slide valve system serves multiple functions: it provides continuous adjustment during normal operation through calibrated bores, maintains flexibility for light loading conditions, and enables stiffening under heavy load by closing the bores. This multi-functionality allows a single device to adapt to various loading conditions without requiring separate systems for comfort and safety modes.
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 design enables precise adjustment of the shock absorber's dynamics, offering both high flexibility and stiffness, thereby enhancing comfort and safety by automatically adapting to vehicle load conditions, reducing the risk of suspension bottoming out and improving braking efficiency.
Implementation Method 1
a thrust spring (34) disposed between the damping piston (4) and the slide (28)
Implementation Method 2
a return spring (42) that applies a constant rearward force to the slide
Implementation Method 3
a first chamber (70) separated from the damping chamber (8), and then a second chamber (72) that delays the movement of the valve
Implementation Method 4
a second chamber (72) that delays the movement of the valve
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a telescopic hydraulic shock absorber with end-of-travel stop, comprising a damping piston (4) which delimits in the front a damping chamber (8), a sleeve (12) fixed in front of the damping piston (4) and fitting at the end of travel and without play around a stop tube (14) by closing first holes (20) of the sleeve (12) or the stop tube (14), the stop comprising a gate (28) axially sliding in the stop tube (14) for closing second holes (46) of said stop tube (14), and comprising a thrust spring (34) arranged between the damping piston (4) and the gate (28), said gate (28) having an axial bore containing a gate piston (40) which delimits at the rear a first chamber (70), which is separated from the damping chamber (8), and in front a second chamber (72) which delays the movement of the gate (28).