Solenoid Valve Multiple Flow-Blocking Portions Reduce Leakage

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Solution Overview

Problem

Solenoid valves in hydraulic control systems face challenges with hydraulic fluid leakage due to narrow gaps between the spool case and land, leading to pressure decreases and increased pump output demands, which can be mitigated by reducing the consumption flow amount without increasing the spool's movement stroke.

Innovation Solution

The solenoid valve design incorporates multiple flow-blocking portions aligned in the axial direction between the supply and output ports and between the output and drain ports, with recesses on the land surfaces to form these flow-blocking passages within the valve hole, reducing leakage and allowing for downsizing without increasing the spool's movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If the overlap length of the flow-blocking portion is increased to reduce hydraulic fluid leakage, then the consumption flow amount is reduced, but the spool movement amount must be increased which leads to upsizing of the solenoid portion

Engineering Contradiction:
Improvehydraulic fluid leakageVSAvoidsolenoid portion size
Core Design Contradiction:
Loss of substanceVSVolume of moving object

Solution Approach 1:

The single flow-blocking portion is segmented into multiple flow-blocking portions (first and second flow-blocking portions) that are formed at different axial positions. This segmentation allows the total overlap length to be increased without requiring a proportional increase in spool movement, as each segment contributes independently to blocking hydraulic fluid leakage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention utilizes the radial dimension by forming multiple flow-blocking portions at different axial positions along the spool. This dimensional approach allows the overlap length to be effectively increased in the axial direction without requiring increased spool stroke, thereby avoiding solenoid portion upsizing while still reducing hydraulic fluid leakage.

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

2Loss of substance

If the spool movement amount is increased to increase the overlap length of the flow-blocking portion, then the hydraulic fluid leakage is reduced, but the solenoid attraction force decreases

Engineering Contradiction:
Improvehydraulic fluid leakageVSAvoidsolenoid attraction force
Core Design Contradiction:
Loss of substanceVSForce

Solution Approach 1:

By segmenting the flow-blocking function into multiple portions, the required spool movement amount is reduced while still achieving the same total overlap length. This reduced movement requirement maintains the solenoid attraction force at adequate levels, as the solenoid does not need to overcome increased spring load from larger spool displacement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the configuration parameter from a single long flow-blocking portion requiring large spool stroke to multiple shorter portions requiring smaller spool stroke. This parameter change allows the system to achieve the same leakage reduction effect while operating within the force capabilities of the existing solenoid.

Inventive Principle:
Principle #35Parameter changes

3Loss of substance

If the spool movement amount is increased to increase the overlap length, then the hydraulic fluid leakage is reduced, but the accuracy of hydraulic control may decrease

Engineering Contradiction:
Improvehydraulic fluid leakageVSAvoidhydraulic control accuracy
Core Design Contradiction:
Loss of substanceVSMeasurement precision

Solution Approach 1:

The segmented flow-blocking portions provide more stable hydraulic control with reduced leakage. The multiple segments create a more gradual and controlled sealing action, improving the precision of hydraulic pressure control while reducing fluid loss through the narrow gap.

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

This configuration effectively reduces hydraulic fluid leakage and allows for a more compact solenoid valve design by increasing the overlap length of flow-blocking portions without increasing the spool's movement, thereby maintaining pressure control and reducing pump output requirements.

Implementation Method 1

a plunger that is driven by electromagnetic force

Methodology Applied
Scientific EffectElectromagnetic force: Electromagnet

Data Source

PatentEP2270373B1Solenoid valve
Publication Date: 2016.04.13 JTEKT CORP
  • EP2270373B1 patent drawingFigure 1
  • EP2270373B1 patent drawingFigure 2
  • EP2270373B1 patent drawingFigure 3

AI summary

In a solenoid valve, multiple flow-blocking portions are formed in a passage between a supply port (23) and an output port (24) and a passage between the output port (24) and a drain port (25). The flow-blocking portions, having an overlap length that corresponds to the movement amount of a spool (30), are formed by the outer peripheral faces of lands (32, 33) and the inner peripheral face of a spool case (10).