Hydraulic End Stop Layout for Monotube Damper Bump Damping
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Solution Overview
Problem
Monotube shock absorbers lack a hydraulic compression bump stop, depriving them of the energy dissipation and smoother wheel braking benefits provided by such stops in twin-tube shock absorbers.
Innovation Solution
A hydraulic stop for monotube shock absorbers that includes an expansion piston with through-holes and a check valve, allowing fluid communication and pressure relief, and a compression piston with orifices, ensuring damping in both compression and rebound strokes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a hydraulic compression bump stop is installed in a twin-tube shock absorber, then energy dissipation and smoother wheel braking are improved, but this solution cannot be applied to monotube shock absorbers due to the splitter piston blocking the installation space
Solution Approach 1:
The patent inverts the traditional hydraulic bump stop design by placing the piston inside the shock absorber body rather than outside. The compression piston is positioned within the lower end of the shock absorber body, allowing it to function in monotube designs where external installation would be blocked by the splitter piston. This internal placement enables the hydraulic compression bump stop to dissipate energy and provide smooth wheel braking in monotube shock absorbers.
2Length of moving object
If the main piston travels its full available stroke, then wheel contact and vehicle handling are improved, but hydraulic saturation generates excessive force that brakes the wheel too quickly
Solution Approach 1:
The patent introduces a hydraulic compression bump stop as an intermediary component between the main piston and the shock absorber body. This bump stop features a compression piston with controllable orifices that mediate the hydraulic flow during compression. The orifices can be selectively opened or closed to regulate the damping force, allowing the main piston to complete its full stroke while preventing excessive braking forces that would otherwise occur during hydraulic saturation.
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 hydraulic stop provides proportional damping forces in both compression and rebound, enhancing vehicle safety and comfort by preventing premature wheel stoppage and ensuring smooth braking.
Implementation Method 1
the expansion piston has at least one through-hole adapted to allow fluid to pass from a first face, called the upper face, of the expansion piston opposite said upper end of the thrust bearing body to a second face, called the lower face, of the expansion piston opposite the compression piston
Implementation Method 2
it also includes a check valve preventing fluid from passing through each of these holes from the lower face to the upper face of the expansion piston
Implementation Method 3
the deformable valve being adapted to deform under the effect of pressure in the thrust bearing body so as to release said at least one hole
Implementation Method 4
Such a hydraulic stop dissipates energy as heat and does not return any force
Data Source
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AI summary
The invention relates to a hydraulic stop for the limit braking of a main piston (5) mounted on a movable rod (5), the hydraulic stop being characterised in that it comprises: - a body, referred to as the stop body (13), - an expansion piston (11) designed to be moved in the stop body (13) by the rod (5) between a compressed position and an extended position, - a compression piston (12) designed to be moved in the stop body (13) by the rod (5) between an extended position and a compressed position; and in that the stop body (13) comprises means (35) for fluid communication between: - a space defined between the extended position of the expansion piston (11) and the extended position of the compression piston (12), and - the outside of the stop body (13).