Hydraulic Stop Shock Absorber With Load-Adaptive Damping Passages

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Solution Overview

Problem

Existing hydraulic shock-absorbers have a fixed damping characteristic curve that does not adjust with varying static loads, which can be a disadvantage in applications like vehicle suspension where load conditions change significantly.

Innovation Solution

A hydraulic shock-absorber with a hollow cylindrical body for the auxiliary piston, featuring adjustable passages that open or close based on static load, using a sliding member and elastic/damping means to alter the damping characteristic curve depending on the load condition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the shock-absorber uses a fixed damping characteristic curve, then the structure is simple, but the adaptability to different static load conditions deteriorates

Engineering Contradiction:
Improveadaptability to static load conditionsVSAvoidstructure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies the dynamics principle by making the damping characteristic adjustable through a sliding member that can change its position along the rod based on static load conditions. The sliding member selectively opens or closes passages in the cylindrical body, dynamically altering the damping characteristic curve to match different load requirements (low load, medium load, high load positions).

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by modifying the damping characteristic through variations in passage configuration. The sliding member's position changes the effective area and configuration of hydraulic passages, thereby changing the damping parameters (damping force, flow resistance) to adapt to different static load conditions.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the shock-absorber provides optimal damping for both low and high load conditions, then the adaptability improves, but the device complexity increases due to additional adjustment mechanisms

Engineering Contradiction:
Improvedamping adjustment rangeVSAvoidadjustment device complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies the self-service principle by designing a passive adjustment mechanism where the sliding member automatically positions itself based on the static load acting on the shock-absorber. The mechanism uses the load itself to drive the adjustment - under high static load, the sliding member is pushed downward to close passages and increase damping; under low load, spring force returns it to open the passages. No external control system is needed.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent uses the sliding member as an intermediary element between the static load and the damping characteristic. The sliding member mediates the relationship by translating static load variations into corresponding changes in passage configuration, thereby indirectly controlling the damping behavior without requiring direct control systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If the shock-absorber uses a hollow cylindrical body with passages for the auxiliary piston, then the adaptability to load conditions improves, but the manufacturing complexity increases

Engineering Contradiction:
Improveload condition adaptabilityVSAvoidcylindrical body manufacturing
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent applies segmentation by dividing the cylindrical body into functional zones with distinct passages positioned at different locations and orientations. The hollow cylindrical body contains multiple separate passages (first passage, second passage, third passage) that can be independently configured, allowing flexible adaptation to different load conditions while maintaining a modular manufacturing approach.

Inventive Principle:
Principle #1Segmentation

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 shock-absorber achieves adjustable damping levels based on static load, providing optimal damping in both low and high load conditions, enhancing its performance and adaptability.

Implementation Method 1

a return spring arranged to bear on the sliding member and arranged within the cylindrical body above the auxiliary piston

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

damping means arranged to cooperate with the sliding member in order to move the latter, depending on the static load acting on the suspension

Methodology Applied
Scientific EffectViscous damping: Viscous Damping

Implementation Method 3

a piston which is slidably mounted in the inner cylindrical tube and is fixed to the lower end of the rod. The piston separates the inner volume of the inner cylindrical tube into a rebound chamber and a compression chamber, which contain an incompressible damping fluid (oil)

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Data Source

PatentEP3891413B1Hydraulic shock-absorber with a hydraulic stop member operating during the compression stroke of the shock-absorber and with an adjustment device for adjusting the behaviour of the hydraulic stop member depending on the vehicle load
Publication Date: 2024.08.21 MARELLI SUSPENSION SYST ITAL SPA
  • EP3891413B1 patent drawingFigure 1~2
  • EP3891413B1 patent drawingFigure 3~4
  • EP3891413B1 patent drawingFigure 5~6

AI summary

The shock-absorber (10) comprises an outer cylindrical tube and an inner cylindrical tube (12), a rod (14), a main piston (16) and a hydraulic stop member (30, 32) received in the compression chamber (20) so as to operate during an end section of the compression stroke of the shock-absorber (10) to cause an increase in the hydraulic damping force applied to the assembly formed by the rod (14) and the main piston (16). The hydraulic stop member (30, 32) comprises a cup -shaped body (30), mounted in the compression chamber (20), and a first auxiliary piston (32), which is mounted on a cylindrical body (34) rigidly connected to the main piston (16) and is configured to slide sealingly in the cup -shaped body (30) during an end section of the compression stroke of the shock-absorber (10), encompassing a working chamber (44) with the cup-shaped body (30). The shock-absorber (10) further comprises a sliding member (46) slidably received inside the cylindrical body (34) for opening or closing at least one first passage (50) of the cylindrical body (34) through which oil may flow from the working chamber (44) of the cup -shaped body (30) to the compression chamber (20) of the shock-absorber.