Shock Absorber Pilot Valve Control for Failsafe Damping

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Solution Overview

Problem

Traditional valve arrangements in shock absorbers often fail to maintain optimal damping characteristics during failsafe control mode, leading to either unrestricted or overly restrictive damping forces due to malfunctions, which are not well-adapted to desired damping characteristics.

Innovation Solution

A valve arrangement that restricts pilot fluid flow by a common restriction in both active and failsafe control modes, ensuring that damping characteristics in failsafe mode follow those of the active mode, using a main valve member and a control valve member with a pilot pressure restriction and a biasing member to regulate fluid flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional valve arrangements are used with failsafe bypass flow, then the valve arrangement provides basic damping during malfunction, but the damping force is not well adapted to desired damping characteristics

Engineering Contradiction:

Improvedamping performance during failsafe modeVSAvoidadaptability to desired damping characteristics

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The valve arrangement is segmented into a main valve member for primary flow control and a control valve member for pilot pressure control. During failsafe mode, the control valve member provides a controlled bypass flow through a common restriction, while the main valve member maintains damping through the pilot pressure mechanism. This segmentation allows independent optimization of failsafe performance and active control characteristics.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the flow control parameters by introducing a common restriction that limits pilot fluid flow during both active and failsafe modes. This parameter change ensures that even during failsafe operation, the damping characteristics follow the tuning made for active control mode, rather than providing unrestricted or overly restrictive flow.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the valve arrangement uses a common restriction for pilot fluid flow in both active and failsafe modes, then damping characteristics remain consistent, but the device complexity increases

Engineering Contradiction:

Improveconsistency of damping characteristicsVSAvoidvalve arrangement structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The common restriction serves multiple functions: it limits pilot fluid flow during active control mode and simultaneously provides the bypass flow limitation during failsafe mode. The control valve member also serves dual purposes by providing active control when actuated and failsafe bypass control when not actuated. This multi-functionality reduces the need for separate components for active and failsafe modes.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention merges the active control and failsafe control functions into a single integrated valve arrangement. The control valve member and main valve member work together in both active and failsafe modes, with the common restriction serving both modes. This merging eliminates the need for separate bypass valves or additional complexity that would be required if active and failsafe controls were completely separate systems.

Inventive Principle:

Principle #5Merging (Combining)

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 approach maintains consistent damping characteristics across both control modes, preventing excessive or insufficient damping forces during failsafe operation, thus improving the adaptability and effectiveness of damping in shock absorbers.

Implementation Method 1

a biasing member resiliently loading the control valve member in a direction towards the pilot chamber

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

a pilot pressure is defined by a hydraulic pressure in the pilot chamber, a main valve member being arranged to interact with a main valve seat in order to restrict a main fluid flow between the first and second ports in response to the pilot pressure acting on the main valve member

Methodology Applied

Scientific EffectHydraulic pressure: Pressure Increase

Implementation Method 3

the pilot fluid flow is restricted by at least one common restriction both during active control mode and failsafe control mode

Methodology Applied

Scientific EffectFlow restriction: Pressure Drop

Data Source

PatentUS11466748B2Valve arrangement and method for controlling a pilot pressure in a valve arrangement

Publication Date: 2022.10.11 ADVANCED SUSPENSION TECHNOLOGY LLC

AI summary

A valve arrangement and a method for controlling a pilot pressure in the valve arrangement for a shock absorber, wherein the valve arrangement comprises a control valve member movable in an axial direction relative a main valve member, a pilot chamber being in fluid communication with a first port and/or a second port. The arrangement and method comprise, during an active control mode, pressure relieving (AM S1) the control valve member and applying an actuating force (AM S2) for controlling the pilot pressure (Pp). Further, during a failsafe control mode, controlling (FM S1) the control valve member by means of the pilot pressure (PP). And finally, during both the active control mode and the failsafe control mode restricting (S3) the pilot fluid flow (PFC, PFR) by at least one common valve seat (R2).