Servovalve Torsion Spring Assembly Using Brazed Work-Hardened Wires

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Solution Overview

Problem

Existing methods for manufacturing torsion springs for servovalves face challenges such as high manufacturing costs, difficulty in achieving precise stiffness, and limitations in producing springs with small diameters due to the use of single-piece material designs, which are costly and sensitive to machining errors.

Innovation Solution

The method involves forming a torsion spring from separate components, including a seat and ears, using pre-formed wires that are work-hardened and brazed together to create sections that connect the components, allowing for improved dimensional accuracy and resistance to fatigue.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If single-piece material design is used for torsion springs, then manufacturing simplicity is maintained, but manufacturing cost increases and machining precision becomes difficult to achieve

Engineering Contradiction:

Improvedimensional accuracyVSAvoidcomponent structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The torsion spring is divided into multiple separate components (ears, seat, and wire sections) that are manufactured independently and then assembled through brazing. This segmentation allows each component to be precision-formed separately using optimized processes, achieving high dimensional accuracy while reducing overall manufacturing complexity compared to single-piece machining.

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If single-piece material design is used for torsion springs, then structural simplicity is maintained, but manufacturing cost increases

Engineering Contradiction:

Improvemanufacturing costVSAvoidcomponent structure

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

3Reliability

If pre-formed work-hardened wires are used, then fatigue resistance is improved, but manufacturing process complexity increases

Engineering Contradiction:

Improvefatigue resistanceVSAvoidmanufacturing process

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The wire sections are pre-formed and work-hardened before assembly into the final torsion spring structure. This preliminary action of work-hardening the wire in advance enhances the fatigue resistance and mechanical properties of the wire sections, making them more durable in the final assembled spring while the modular approach actually simplifies the overall manufacturing process.

Inventive Principle:

Principle #10Preliminary action

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 approach reduces manufacturing costs, ensures precise stiffness, and enhances fatigue resistance by utilizing pre-formed wires that can be work-hardened, resulting in a more reliable and accurate torsion spring with improved mechanical properties.

Implementation Method 1

utilizing pre-formed wires that can be work-hardened

Methodology Applied

Scientific EffectWork hardening: Shock Hardening

Implementation Method 2

brazing the wire to the first and second ears and to the seat

Methodology Applied

Scientific EffectBrazing: Brazing

Data Source

PatentUS10955020B2Method for manufacturing a torsion spring for use in a servovalve and the torsion spring itself

Publication Date: 2021.03.23 HAMILTON SUNDSTRAND CORP

AI summary

A new method of forming a torsion spring for use in a servovalve is described. The method comprises individually forming the different components of the torsion spring and then connecting the individual components together using a brazing process. The torsion spring created by this method is also described.