Spool Valve Guiding Section Prevents Housing Deformation

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Solution Overview

Problem

Spool valve housings in hydraulic systems, particularly in aerospace applications, deform under high fluid pressure, causing the spool to lock in position and preventing proper function, which may require replacement.

Innovation Solution

Incorporating guiding sections with radially extending surfaces that connect adjacent guiding surfaces, forming a 'pocket' to expose a portion of the metering edge to the groove, preventing housing deformation while allowing fluid communication and supporting the spool housing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If high fluid pressure is applied in the housing and control ports, then the spool valve can control fluid movement effectively, but the housing deforms adjacent to the control port causing the spool to lock in position

Engineering Contradiction:
Improvefluid pressure control capabilityVSAvoidspool movement reliability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent applies local quality by creating a reinforcing structure specifically at the control port region where deformation occurs. The radially extending surface forms a localized reinforcement that distributes stress in the housing wall adjacent to the control port, preventing deformation only where needed without affecting other parts of the housing.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent introduces a new geometric dimension by adding a radially extending surface that projects into the control port passage. This creates a three-dimensional reinforcing feature that adds structural support in the radial dimension, preventing the housing wall from deforming under pressure while maintaining fluid flow paths.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Strength

If the radially extending surface extends far enough to support the housing, it may impede fluid flow through the control port

Engineering Contradiction:
Improvehousing structural supportVSAvoidfluid flow rate
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The reinforcing structure is designed with local quality by positioning the radially extending surface at a specific location where it provides maximum structural support while minimizing interference with fluid flow. The surface extends only far enough to distribute stress effectively without protruding into the main fluid passage.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent applies partial action by extending the radially extending surface only to the degree necessary to prevent housing deformation, rather than extending it fully across the control port. This partial extension provides sufficient structural support while leaving adequate clearance for fluid flow.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3431843B1Spool valve
Publication Date: 2020.05.06 HAMILTON SUNDSTRAND CORP
  • EP3431843B1 patent drawingFigure 1a
  • EP3431843B1 patent drawingFigure 1b
  • EP3431843B1 patent drawingFigure 2

AI summary

A spool (10) for a spool valve (20) having a longitudinal axis (L). The spool (10) comprising: a plurality of lands (12) each having a substantially radially extending metering edge (13) and an axially extending circumferential surface (15); a plurality of grooves (14) separating each of the plurality of the lands (12); and a guiding section (16) located axially between at least one land (12) and an adjacent groove (14). The guiding section (16) comprising a plurality of circumferentially spaced guiding surfaces (17) being substantially flush and contiguous with the circumferential surface (15) of the land (12), wherein the guiding section (16) allows fluid communication between the groove (14) and the metering edge (13) of the land (12).