Sensor Case Ribs for Resin Sealing and Sheath Positioning

Solution Overview

Problem

Existing position detection switches for pistons in air and hydraulic cylinders face issues with resin displacement during manufacturing, leading to inadequate sealing, potential electrical defects, and reduced durability due to contact between the sheath and sensor case inner wall, which can result in separation or breakage under external forces and temperature changes.

Innovation Solution

The introduction of ribs on the inner wall of the sensor case, which separate the sheath from the inner wall during resin injection, allowing the resin to fill gaps effectively and create a strong, durable joint between the sensor case, sheath, and resin, enhancing protection against dust, moisture, and external forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If molten resin is filled into the sensor case during manufacturing, then the substrate and components are secured inside the sensor case, but the lead wire and sheath are displaced by resin pressure and brought into contact with the inner wall of the sensor case, resulting in insufficient resin spreading and inadequate sealing

Engineering Contradiction:

Improvesealing qualityVSAvoidpositioning accuracy of sheath

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

Ribs are pre-formed on the inner wall of the sensor case before resin injection. These ribs act as positioning structures that guide the sheath into proper alignment and prevent displacement during the subsequent resin filling process, ensuring the sheath remains centered and sealed properly

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The ribs serve as intermediary structures between the sensor case inner wall and the sheath. They create controlled gaps that allow molten resin to flow through and seal the interface between the sheath and sensor case, preventing direct contact that would cause displacement while ensuring adequate sealing

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If the sheath is brought into contact with the inner wall of the sensor case, then positioning is simplified, but the resin cannot sufficiently spread to the contact portion, resulting in separation or breakage under external forces and temperature changes

Engineering Contradiction:

Improveassembly simplicityVSAvoidjoint strength between sheath and sensor case

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

Ribs are pre-formed on the inner wall of the sensor case before resin injection. These ribs act as positioning structures that guide the sheath into proper alignment and prevent displacement during the subsequent resin filling process, ensuring the sheath remains centered and sealed properly

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The ribs serve as intermediary structures between the sensor case inner wall and the sheath. They create controlled gaps that allow molten resin to flow through and seal the interface between the sheath and sensor case, preventing direct contact that would cause displacement while ensuring adequate sealing

Inventive Principle:

Principle #24Intermediary (Mediator)

3Volume of moving object

If the sensor case is thin-walled for compact design, then the overall size is reduced, but the sensor case is more susceptible to expansion and contraction under external forces and temperature changes, increasing risk of separation or breakage

Engineering Contradiction:

Improvesensor case sizeVSAvoiddurability against external forces

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

Ribs are pre-formed on the inner wall of the sensor case before resin injection. These ribs act as positioning structures that guide the sheath into proper alignment and prevent displacement during the subsequent resin filling process, ensuring the sheath remains centered and sealed properly

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The ribs serve as intermediary structures between the sensor case inner wall and the sheath. They create controlled gaps that allow molten resin to flow through and seal the interface between the sheath and sensor case, preventing direct contact that would cause displacement while ensuring adequate sealing

Inventive Principle:

Principle #24Intermediary (Mediator)

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 a robust and reliable joint between the sensor case and sheath, providing improved protection against dust, moisture, and mechanical stress, while maintaining electrical integrity by preventing resin displacement and ensuring proper sealing.

Implementation Method 1

during injection of a molten resin into the sensor case

Methodology Applied

Scientific EffectResin injection:

Implementation Method 2

the resin for sealing the substrate

Methodology Applied

Scientific EffectSealing:

Data Source

PatentUS10948384B2Position detection switch and method for manufacturing same

Publication Date: 2021.03.16 SMC CORP

AI summary

A position detection switch is provided with a case having a cylindrical part that has a plurality of ribs on an inner circumferential wall thereof along the axial direction thereof. Accordingly, the strength of the case is increased and running of a molten resin for fixing a substrate disposed on the inside are improved when the molten resin is injected from a long groove of the case. The contact surface area between the ribs and a sheath is increased whereby durability against an external force and temperature variation is increased.