Spool Valve Seal Wing Arrangement for Low-Friction Switching

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Solution Overview

Problem

Existing spool valves in hydraulic and pneumatic machinery face challenges with o-ring seals, including frictional resistance affecting actuation speed, difficult installation and maintenance, and frequent seal changes leading to surface scratching and reduced efficiency.

Innovation Solution

The design incorporates circumferential seal wings and annular recesses on the spool, minimizing frictional interaction and allowing for faster switching times, improved durability, and easier assembly, with a unitary seal formed by the wings and tubular connector, and dynamic seals to reduce friction and facilitate movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If o-rings are used to seal the bore in a spool valve, then sealing between adjacent fluid chambers is achieved, but frictional force opposes actuation force and actuation speed cannot be controlled

Engineering Contradiction:

Improvesealing effectivenessVSAvoidactuation speed

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The seal is divided into multiple independent circumferential seal wings (first seal wing, second seal wing) that are arranged on the spool. Each seal wing seals against a different surface (bore or annular recess), distributing the sealing function across multiple segments rather than relying on a single continuous o-ring against the bore.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The seal is extracted from the traditional groove configuration and repositioned as circumferential seal wings directly on the spool. This extraction removes the seal from its conventional location where it would frictionally engage the bore, allowing the seal wings to abut annular recesses instead, thereby reducing frictional opposition to actuation.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If o-rings are installed in grooves using dedicated tooling, then proper sealing is achieved, but installation and maintenance become challenging and time-consuming

Engineering Contradiction:

Improvesealing effectivenessVSAvoidinstallation ease

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The circumferential seal wings are pre-positioned on the spool during manufacturing, with their sealing surfaces oriented to abut the annular recesses. This preliminary configuration eliminates the need for complex installation tooling and procedures, as the seal structure is inherently ready for function upon assembly.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Instead of forcing the seal into a groove from the outside (traditional approach), the seal wings are designed to snap into place or be retained on the spool, inverting the installation logic. The seal structure itself provides the retention mechanism rather than relying on external grooves and tooling.

Inventive Principle:

Principle #13The other way round (Inversion)

3Ease of repair

If o-rings are removed using pick tools, then spent seals are replaced, but the spool surface gets scratched and valve efficiency reduces

Engineering Contradiction:

Improveseal replacementVSAvoidsurface scratching

Core Design Contradiction:

Ease of repairVSObject-affected harmful factors

Solution Approach 1:

The circumferential seal wings are designed to be self-retaining on the spool through their geometric configuration and elastic properties. This self-service design eliminates the need for pick tools or external removal mechanisms, allowing seals to be replaced without mechanical prying that would scratch the spool surface.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The seal wings are made of elastomeric material that provides flexibility for installation and removal. This flexible shell design allows the seals to be easily manipulated and replaced without rigid tools, preventing surface damage while maintaining sealing effectiveness.

Inventive Principle:

Principle #30Flexible shells and thin films

4Ease of repair

If seals are frequently changed, then maintenance is performed, but seal durability decreases and operational costs increase

Engineering Contradiction:

Improvemaintenance frequencyVSAvoidseal durability

Core Design Contradiction:

Ease of repairVSDuration of action of stationary object

Solution Approach 1:

The seal wings are designed to abut the annular recesses rather than frictionally engage the bore. This configuration converts the potential harm of frequent seal changes into a benefit by reducing wear on both the seals and the spool surface, thereby extending seal durability and reducing operational costs.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS11826944B2Directional control valve and a sealing arrangement therefore

Publication Date: 2023.11.28 NORGREN GMBH

AI summary

A valve (10) comprising a bore (14) extending about an actuation axis (A), wherein a spool (34) inside the bore (14) is actuated between a first working position and a second working position, and a first circumferential seal wing (56A) and a second circumferential seal wing (56B) being arranged on the spool (34). In the first working position, the first seal wing (56A) abuts to an outer first recess wall (24a) and the second seal wing (56B) abuts to an inner second recess wall (24c), so as to open some flow paths and close other flow paths. In the second working position, the first seal wing (56A) abuts to an inner first recess wall (24b) and the second seal wing (56B) abuts to an outer second recess wall (24d), so as to close some flow paths and open other flow paths.