Temperature Sensor Main Body Positioning in Injection Molding

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Solution Overview

Problem

The main body of temperature sensors is prone to displacement during injection molding, leading to inaccurate positioning and temperature variation, as it is not effectively supported by the resin mold, causing exposure and potential contamination.

Innovation Solution

A temperature sensor design where the main body is supported by a first housing with a resin mold layer that surrounds the outer periphery, and a second housing covers the main body, ensuring accurate positioning and preventing displacement, with the sealing glass and ceramic protection pipe exposed to maintain airtightness and mechanical reinforcement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the main body is disposed in a cavity of a mold for injection molding, then the resin mold can be formed, but the main body is displaced by the pressure of the molten resin

Engineering Contradiction:
Improveinjection molding processVSAvoidpositioning accuracy of main body
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by providing support structures (protrusions from the mold or separate support fixtures) that hold the main body in its predetermined position before the injection molding process begins. This prevents displacement when the molten resin is injected, as the main body is already secured in place.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses an intermediary support structure (protrusions or fixtures) that mediates between the molten resin pressure and the main body. This intermediary element absorbs or distributes the pressure, preventing direct force transmission that would cause displacement of the main body.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If the main body is displaced during injection molding, then the resin mold can still be formed, but the main body is exposed to outside or the resin mold thickness becomes non-uniform

Engineering Contradiction:
Improveresin mold formationVSAvoidsealing performance and detection accuracy
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

By securing the main body in position before injection molding through support protrusions, the patent prevents displacement that would lead to exposure or non-uniform thickness. This preliminary positioning ensures reliable sealing and consistent resin mold geometry.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The support structures provide preliminary anti-action by counteracting the displacement force before it can occur. The protrusions from the mold or separate support fixtures apply opposing force to the main body, preventing the harmful effect of displacement and subsequent exposure.

Inventive Principle:
Principle #9Preliminary anti-action

3Ease of manufacture

If the main body is fixed by a resin mold in secondary molding, then the primary molded body can be fabricated, but the displacement of the main body continues after secondary molding

Engineering Contradiction:
Improvesecondary molding processVSAvoidpositioning accuracy of main body
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent establishes the correct position of the main body during primary molding using support protrusions. This preliminary positioning is maintained through secondary molding, ensuring the main body remains at the desired position without further displacement.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Instead of trying to prevent displacement during secondary molding, the patent inverts the approach by ensuring the main body is already correctly positioned before secondary molding begins. The support structures are designed to maintain rather than adjust the position, reversing the conventional sequence of positioning and molding.

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP3382358B2Temperature sensor
Publication Date: 2024.02.28 SHIBAURA ELECTRONICS CO LTD
  • EP3382358B2 patent drawingFigure 1A~1C
  • EP3382358B2 patent drawingFigure 2A~2B
  • EP3382358B2 patent drawingFigure 3A~3C

AI summary

A temperature sensor of the present invention includes a sensor element (11) that includes a main body (13) and paired lead wires (15 and 15) drawn from the main body (13), and a first housing (19) that includes a resin mold layer and covers the sensor element (11). The main body (13) is partially or entirely exposed, continuously in a circumferential direction, from the first housing (19) without being covered with the first housing. In the temperature sensor, the main body (13) includes a thermosensitive body (13A) and a sealing glass (13B) covering the thermosensitive body (13A), and the sealing glass (13B) is exposed from the first housing (19) .