Bidirectional Piston Slide Valve with Pressure Feedback

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Solution Overview

Problem

Existing piston slide valves for vehicle shock absorbers require significant installation space and are prone to collisions with surrounding components due to their directional flow limitations, necessitating separate valves for each flow direction and increased space usage.

Innovation Solution

A bidirectional spool valve design with pressure feedback pins in both fluid connections allows for proportional control in both flow directions, reducing space requirements by using a single valve that can operate effectively in both directions, with symmetrical bypass lines and pressure-balanced piston design to manage flow forces and pressure feedback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single directional valve is used for each flow direction, then flow control is achieved, but installation space increases and collision risk with surrounding components increases

Engineering Contradiction:
Improveflow control capabilityVSAvoidinstallation space
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The piston slide valve is designed to control fluid flow in both directions (from first fluid connection to second, and vice versa) using a single valve body. The valve features symmetric bypass lines and pressure feedback mechanisms that enable bidirectional operation, eliminating the need for separate valves for each flow direction and reducing installation space requirements

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If separate valves are provided for each flow direction, then flow control in both directions is achieved, but device complexity increases

Engineering Contradiction:
Improvebidirectional flow controlVSAvoidvalve configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention combines the functionality of two separate directional valves into a single bidirectional piston slide valve. The valve body integrates symmetric bypass lines, dual pressure feedback pins, and a unified piston mechanism that can regulate flow in both directions, thereby reducing the number of components and simplifying the overall valve configuration

Inventive Principle:
Principle #5Merging (Combining)

3Manufacturing precision

If pressure feedback pins are added to both fluid connections, then proportional characteristic in both flow directions is achieved, but manufacturing complexity increases

Engineering Contradiction:
Improveproportional flow controlVSAvoidvalve assembly
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

While the valve achieves symmetric bidirectional control, the manufacturing process benefits from a standardized asymmetric design approach. The pressure feedback pins are positioned symmetrically in the valve body, but their integration follows a systematic manufacturing sequence that first establishes the valve body geometry, then adds the feedback mechanisms, thereby managing complexity through structured assembly rather than simultaneous complex fabrication

Inventive Principle:
Principle #4Asymmetry

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 solution enables a compact, direction-independent valve that can manage flow forces and pressure feedback symmetrically, reducing the need for separate valves and minimizing space while maintaining efficient flow control and energy efficiency.

Implementation Method 1

an electromagnetically actuated piston slide valve according to the invention, which changes its flow resistance and thereby the damping effect of the overall system depending on the energization of the excitation coil of the electromagnet

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

an axial bore is provided in the axial fluid inlet, in which a so-called pressure return pin is mounted in an axially displaceable manner. In this way, a fluid pressure present at the axial fluid inlet is transmitted to the piston by means of the pressure return pin

Methodology Applied
Scientific EffectPressure transmission: Pascal's Law

Data Source

PatentEP2813728B1Piston slide valve
Publication Date: 2019.01.30 RAUSCH & PAUSCH GMBH
  • EP2813728B1 patent drawingFigure 1
  • EP2813728B1 patent drawingFigure 2
  • EP2813728B1 patent drawingFigure 3

AI summary

An electromagnetically actuated piston slide valve with a first axial fluid port (1) and a second fluid port (2) and at least one radially extending fluid channel (8) connecting the two fluid ports (1, 2) and with an electrically energizable coil (16) for generating an electromagnetic field has a piston slide arrangement with a piston (3) which is axially displaceable against a force of at least one first preload spring (6) in order to control a free cross-sectional area of ​​the fluid channel (8) by energizing the coil (16).At least one axial bore (21) is provided, which is operationally associated with the first fluid port (1) and in which an axially displaceable first pressure feedback element (22) is arranged such that a fluid pressure applied to the first fluid port (1) can be transmitted to the piston (3) by means of the first pressure feedback element (22), so that the piston (3) is forced towards an open position. Furthermore, at least one bypass line (23, 25) operationally associated with the second fluid port (2) is provided with an axially extending section (25) in which an axially displaceable second pressure feedback element (24) is arranged such that a fluid pressure applied to the second fluid port (2) can be transmitted to the piston (3) by means of the second pressure feedback element (24), so that the piston (3) is forced towards an open position.