Photoelectric Sensor Sealing via Cured Liquid Agent
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Solution Overview
Problem
Existing multiple-optical-axis photoelectric sensors face challenges in maintaining a stable seal against dust and liquid ingress due to gaps generated by position deviations, thermal expansion, and weak chemical resistance of sealing materials, leading to potential malfunctions.
Innovation Solution
A seal structure incorporating a cured liquid sealing agent that connects the leading ends of a seal member and an elastic member, ensuring gap-free assembly of the light transmission plate, case body, and caps, with the seal member and elastic member integrated by the cured liquid agent, and additional features like engagement units to maintain the light transmission plate's position and prevent thermal contraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a double-sided adhesive tape is used to fix the light transmission plate to the case body, then the assembly process is simplified, but the chemical resistance deteriorates when contaminated with chemicals
Solution Approach 1:
A resin member is introduced as an intermediary component between the light transmission plate and the case body. This resin member provides both adhesive bonding capability for easy assembly and chemical resistance for reliable operation in contaminated environments, resolving the contradiction between manufacturing ease and chemical resistance
Solution Approach 2:
The sealing structure uses a composite approach by combining the light transmission plate, resin member, and case body into a multi-material assembly. The resin member acts as a composite material that integrates both adhesive and chemically resistant properties, eliminating the need for separate adhesive tapes
2Reliability
If rubber packing is used to seal the gap between caps and case body, then the sealing performance is improved, but the device complexity increases
Solution Approach 1:
The resin member serves multiple functions simultaneously: it seals the gap between the cap and case body, supports the light transmission plate, and provides chemical resistance. By merging these multiple sealing and support functions into a single component, the device complexity is reduced while maintaining reliable sealing performance
3Manufacturing precision
If the light transmission plate is fixed rigidly to the case body, then the manufacturing precision is improved, but the thermal expansion resistance deteriorates
Solution Approach 1:
The resin member provides a dynamic, flexible connection between the light transmission plate and case body rather than a rigid fixed connection. This flexibility allows the assembly to accommodate thermal expansion and contraction of the light transmission plate while maintaining proper positioning, resolving the contradiction between precision and thermal adaptability
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 effectively seals the casing, preventing dust and liquid ingress, ensuring stable operation by eliminating gaps and accommodating thermal changes, and simplifies the assembly process with easy detection of incomplete connections.
Implementation Method 1
a cured liquid sealing agent interposed between leading ends of the seal member and the elastic member
Implementation Method 2
the light transmission plate is supported by each support of the case body with an elastic member interposed therebetween
Implementation Method 3
the pair of caps and the light transmission plate are fixed to the case body such that a gap is not generated
Data Source
Figure 1
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AI summary
A light projector (10) and a light receiver (20) each includes a case body (3), a light transmission plate (4) closing an opening in a front face of the case body (3), and a pair of caps (5) closing openings in end faces of the case body (3). The case body (3) includes first supports (35) supporting side edges of the light transmission plate (4), the caps (5) respectively include second supports (53) supporting ends of the light transmission plate (4), the light transmission plate (4) is supported by the first supports (35) and the second supports (53) with an elastic member interposed between the light transmission plate (4) and the first and second supports (35, 53), and the cap (5) is fixed to the case body (3) while the seal member abutting on the end face of the case body (3) is interposed between the cap (5) and the case body (3). A cured liquid sealing agent is interposed between leading ends of the seal member and the elastic member.