Plastic Proportional Spool Valve Assembly Without Fit Deformation

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Solution Overview

Problem

Existing proportional spool valves in oil pumping systems of motor vehicles face mechanical deformations and force imbalances during assembly, affecting the accuracy and functionality of volume flow adjustment due to traditional aluminum components and interference fits.

Innovation Solution

The use of plastic injection-molded components for both the spring holder and valve housing, with an integral welded connection to minimize physical effort and avoid mechanical deformations, employing ultrasonic or laser welding for a secure and precise assembly that compensates for tolerances and ensures consistent actuation performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional aluminum components with interference fits are used for assembling spring holder and valve housing, then mechanical strength and connection stability are improved, but mechanical deformations and force imbalances occur during assembly affecting fitting accuracy

Engineering Contradiction:

Improveconnection strengthVSAvoidfitting accuracy

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The patent replaces the traditional mechanical interference fit connection with ultrasonic welding, substituting a mechanical assembly system with a thermal-vibrational welding system. This eliminates the need for forceful interference fits that cause deformations, while achieving strong, precise connections through localized melting and bonding of the plastic components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the material parameter from metal (aluminum) to plastic for both spring holder and valve housing. This material parameter change enables the use of welding instead of interference fits, fundamentally altering the assembly method from mechanical force-based to thermal-vibration-based joining, thereby resolving the contradiction between connection strength and fitting accuracy.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If aluminum spring holder is pressed into valve housing by caulking, then assembly is simplified and productivity is improved, but mechanical deformations occur on valve housing and valve spool affecting functionality

Engineering Contradiction:

Improveassembly efficiencyVSAvoidfunctional integrity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent replaces the mechanical caulking process with ultrasonic welding. Instead of using mechanical pressing and deformation to join components, the ultrasonic welding process uses high-frequency vibrations to generate heat and melt the plastic surfaces, creating a strong bond without mechanical deformation of the components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If plastic injection-molded components are used for spring holder and valve housing, then manufacturing precision and tolerance compensation are improved, but connection strength may be reduced compared to metal components

Engineering Contradiction:

Improvedimensional accuracyVSAvoidconnection strength

Core Design Contradiction:

Manufacturing precisionVSStrength

Solution Approach 1:

The patent changes the joining method parameter from mechanical interference fit to ultrasonic welding. This parameter change is specifically suited for plastic materials, allowing the achievement of both high connection strength and preservation of dimensional accuracy. The ultrasonic welding process creates a strong bond by melting and fusing the plastic surfaces together, matching or exceeding the strength of the original injection-molded components.

Inventive Principle:

Principle #35Parameter changes

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 solution reduces mechanical stress and maintains fitting accuracy, enabling optimized adjustment of the spring bias and self-regulation of volume flow, ensuring consistent valve performance even when the electromagnetic displacement device fails, and compensating for production and dimensional tolerances.

Implementation Method 1

employing ultrasonic or laser welding for a secure and precise assembly

Methodology Applied

Scientific EffectUltrasonic welding: Ultrasonic Vibration

Implementation Method 2

employing ultrasonic or laser welding for a secure and precise assembly

Methodology Applied

Scientific EffectLaser welding: Laser Beam Welding

Data Source

PatentUS11346337B2Proportional spool valve for adjusting the displaced volume of a displacement pump, assembly method and system

Publication Date: 2022.05.31 ETO MAGNETIC GMBH

AI summary

A proportional spool valve (1) for adjusting a displaced volume of a displacement pump, in particular of an oil pump in a motor vehicle, the proportional spool valve (1) includes a valve housing (2) and a valve spool (3) which is mounted in the valve housing (2) and displaceable along a displacement axis (V) and which can be displaced against the spring force of a valve spring (6) axially supported on a spring holder (7) which is fixed relative to the valve housing (2) by energizing an electrical coil assembly (10), characterized in that wherein both the preferably single-piece spring holder (7) and the valve housing (2) are made of plastic and that the spring holder (7) is welded to the valve housing (2), an integral welded connection (9) being formed.