Thermoactuator Attachment Structure for Engine Mounting

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Solution Overview

Problem

The existing thermoactuators face issues with secure attachment to engines, leading to potential deformation, wax leakage, and malfunction due to twisting stresses and exposure to corrosion, which compromises the operating characteristics and positioning of the shaft.

Innovation Solution

A thermoactuator with a non-rotational attachment structure that uses crimping for assembly and a tapered housing compartment with an O-ring to prevent twisting and exposure, allowing for secure, compact, and accurate positioning without compromising the operating characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the supporting portion is screwed onto the engine for attachment, then the thermoactuator can be securely mounted, but twisting stresses cause deformation of the crimped end and potential wax leakage

Engineering Contradiction:
Improveattachment securityVSAvoidstructural integrity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The attachment structure is divided into separate functional components: a housing compartment with a tapered portion for positioning, a guard portion for protection, and a flange for mounting. This segmentation allows the supporting portion to be pressed into the housing compartment without rotational twisting, while the flange provides secure mounting to the engine block, resolving the contradiction between attachment security and structural integrity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

An O-ring seal is introduced as an intermediary element between the supporting portion and the housing compartment. This O-ring prevents wax leakage by creating a reliable seal while allowing the supporting portion to be pressed in without twisting stresses, thus protecting the crimped end from deformation while maintaining attachment security.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If the supporting portion is pressed into the casing for attachment, then assembly is simplified, but the crimped end may deform under installation stress

Engineering Contradiction:
Improveassembly simplicityVSAvoidcrimped end deformation
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The housing compartment is designed with a tapered portion at the rim of the opening, creating a localized guiding feature. This tapered portion provides precise positioning and guidance during insertion, ensuring that the supporting portion is pressed in axially without twisting or deforming the crimped end, while maintaining assembly simplicity.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If the thermoactuator is exposed to the outside environment, then assembly is easier, but corrosion and loosening occur

Engineering Contradiction:
Improveassembly easeVSAvoidcorrosion resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The thermoactuator is nested within the housing compartment and attached to the engine block via the flange. This nested configuration protects the thermoactuator from external corrosion while maintaining assembly ease, as the entire assembly is secured to the engine block in a single operation without requiring separate protection of the thermoactuator components.

Inventive Principle:
Principle #7Nested doll (Nesting)

4Measurement precision

If the shaft is positioned accurately, then the shutter control is precise, but the attachment structure becomes complex

Engineering Contradiction:
Improveshaft positioning accuracyVSAvoidattachment structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The housing compartment features an asymmetric tapered portion at the rim of the opening, which provides precise positioning of the supporting portion during insertion. This asymmetric feature ensures accurate shaft positioning without requiring complex attachment structures, as the tapered portion guides the supporting portion into the correct position while the flange provides secure mounting.

Inventive Principle:
Principle #4Asymmetry

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

The solution ensures secure attachment without twisting stresses, prevents wax leakage, and maintains the operating characteristics, reducing the risk of corrosion and loosening, while allowing for easy assembly and precise positioning of the shaft.

Implementation Method 1

a shaft is moved back and forth by expansion and contraction of wax induced by changes in temperature

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

an O-ring provided between the tapered portion and the guard of the supporting portion

Methodology Applied
Scientific EffectSealing:

Data Source

PatentEP3078853B1Thermoactuator and attachment structure thereof
Publication Date: 2019.02.20 NIPPON THERMOSTAT CO LTD
  • EP3078853B1 patent drawingFigure 1
  • EP3078853B1 patent drawingFigure 2~3
  • EP3078853B1 patent drawingFigure 4

AI summary

A thermoactuator (1) easily installed in an object (30) without compromising the operating characteristics of the thermo-element (9) has an element case (3), containing wax (2) that expands and contracts with changes in temperature; a supporting portion (5) attached at one end to the element case (3) by crimping, slidably supporting a shaft (6) at another end; a cylindrical casing (10) having an opening in one end, at least a portion of the supporting portion (5) pressed through the opening in the one end of the cylindrical casing (10); and a flange (10b) expanding outward from the one end of the cylindrical casing (10), in which through-holes (10c) are formed for mounting the thermoactuator (1) to an object (2) to which the thermoactuator (1) is to be attached. The element case (3) is supported by one end of the supporting portion (5) housed within the object (30) to which the thermoactuator (1) is to be attached and the casing (10) is mounted on the object via the flange (10b).