Hydraulic Suspension Stopper With Inertial Mass for Load Compensation
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Solution Overview
Problem
Existing hydraulic limit stops for motor vehicle suspensions struggle to adjust effectively for different vehicle loads and attitudes, leading to variable travel distances before reaching the stop and compromised ride quality, especially on uneven roads.
Innovation Solution
A hydraulic limit stop with a rear compression chamber linked to an axially sliding piston, utilizing a forward force from an advance spring and a height compensation chamber supplied by a pressurized fluid reservoir with a passage restriction, allowing for consistent travel distance before reaching the stop regardless of load, through fluid dynamics and inertia.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a hydraulic end stop is used to provide rigid buffering for end-of-travel stopping, then stopping force is improved, but ride comfort deteriorates due to rapid suspension travel termination
Solution Approach 1:
The hydraulic end stop dynamically adjusts its braking force based on suspension compression speed. During normal operation, the piston moves freely allowing smooth suspension travel. During impact events, the inertial column generates increased hydraulic pressure that progressively increases braking force, providing progressive rather than abrupt stopping that maintains ride comfort while ensuring effective end-of-travel limitation
Solution Approach 2:
The system changes the hydraulic pressure parameter in real-time based on the inertial effects of the moving fluid column. As the piston accelerates during compression, the fluid inertia creates increasing pressure against the restriction orifice, thereby dynamically adjusting the braking force parameter to match the severity of the suspension event
2Object-generated harmful factors
If suspension spring stiffness is reduced to improve filtering of high-frequency excitations, then ride comfort is improved, but handling degradation occurs leading to low-frequency oscillations on degraded roads
Solution Approach 1:
The hydraulic end stop acts as an intermediary element between the suspension spring and the wheel assembly. It provides supplemental support during low-frequency, high-amplitude events on degraded roads, compensating for the reduced spring stiffness and preventing excessive body roll and oscillations while maintaining the benefits of soft spring operation for high-frequency filtering
3Device complexity
If a hydraulic end stop with fixed braking characteristics is used, then device complexity is reduced, but adaptability to different vehicle loads and attitudes deteriorates
Solution Approach 1:
The hydraulic end stop is self-adjusting through the inertial properties of the moving fluid column. The system automatically adapts to different vehicle loads and suspension compression rates without external control, as the inertial forces generated by the fluid naturally scale with the severity and speed of the compression event, providing appropriate braking force for each condition
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 solution provides a consistent travel distance before the end-of-travel stop across varying vehicle loads and attitudes, maintaining effective braking quality and improving ride stability on different road conditions without electrical control.
Implementation Method 1
transmits its fluid through an inertial fluid column to a reservoir maintaining pressure in the fluid
Implementation Method 2
subjected to a forward force from an advance spring connected to a suspension element during compression of this suspension
Implementation Method 3
a rearward force from a height compensation chamber bearing on a body of the stop, supplied with pressurized fluid from the reservoir through a fluid passage restriction
Data Source
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AI summary
Disclosed is a hydraulic end-of-travel stop for motor vehicle suspension, braking an axial movement directed in a forward direction (AV), comprising a rear compression chamber (22) which, during braking, transmits its fluid through an inertial fluid column (36), towards a container (16) maintaining a pressure in the fluid, the compression chamber (22) being linked to an axially sliding piston (20), which experiences a force towards the front originating from an advancing spring (40) connected to an element of the suspension (2), during the compression of this suspension, and a force towards the rear originating from a height compensation chamber (26) bearing on a body of the stop (10), supplied with pressurised fluid by the container (16) via a fluid passage restrictor (30).