Explosion-proof stud assembly with plastic deformation
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Solution Overview
Problem
Existing explosion-proof assemblies for guiding electrically conductive studs through walls face challenges in ensuring reliable ignition protection due to micro cracks in epoxy resin connections, leading to potential water infiltration and failure in static pressure tests.
Innovation Solution
An explosion-proof assembly comprising a rigid, electrically conductive stud with inclined surface portions and an elastically deformable sleeve, combined with a plastically deformable connecting body that forms a frictionally engaged connection without an integrally bonded adhesive, ensuring a gap-free and secure assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an epoxy resin mass is used to connect the stud and the connecting body, then electrical insulation is provided, but micro cracks can form leading to water infiltration and failure in static pressure tests
Solution Approach 1:
The invention removes the epoxy resin bonding process entirely from the assembly. The stud is inserted directly into the connecting body without any adhesive, eliminating the source of micro cracks and water infiltration while simplifying the manufacturing process.
Solution Approach 2:
A sleeve is introduced as an intermediary component between the stud and the connecting body. This sleeve provides the necessary electrical insulation and mechanical connection without requiring epoxy resin bonding, thus avoiding the reliability issues associated with adhesive cracking.
2Strength
If the stud and connecting body are coated with galvanic coating or additional layers to achieve permanent connection, then connection strength is improved, but manufacturing complexity and production time increase
Solution Approach 1:
The invention eliminates galvanic coatings and additional surface treatment layers. The permanent connection is achieved through the mechanical interference fit between the stud, sleeve, and connecting body, removing the need for complex coating processes.
Solution Approach 2:
The connection is divided into distinct functional segments: the stud provides structural support, the sleeve provides insulation and frictional engagement, and the connecting body provides anchoring. Each component is simple in design, reducing overall manufacturing complexity.
3Ease of manufacture
If a frictionally engaged connection is used without integrally bonded adhesive, then production is simplified and gap-free assembly is achieved, but connection reliability must be ensured
Solution Approach 1:
The sleeve is pre-fitted onto the stud before insertion into the connecting body. This preliminary assembly ensures proper positioning and eliminates gaps, while the frictional engagement is designed to develop full connection strength upon installation without requiring additional bonding steps.
Solution Approach 2:
The connection utilizes composite material properties: the metallic stud and connecting body provide mechanical strength, while the polymeric sleeve provides frictional engagement and electrical insulation. This material combination achieves both simplicity and reliability.
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 assembly effectively prevents ignition transmission and meets standard requirements by providing a reliable, easy-to-produce, and gap-free connection that withstands static pressure tests without the need for complex bonding processes.
Implementation Method 1
The sleeve is preferably made of an elastically radially deformable material, for example an elastomer, polyamide, polytetrafluoroethylene
Implementation Method 2
The connecting body has a connecting portion which surrounds at least one length portion of the sleeve. The connecting portion is plastically deformed and presses radially inwardly against the sleeve as a result of this deformation
Implementation Method 3
Due to the plastic deformation of the connecting portion, a frictionally engaged connection is formed between the connecting body and the sleeve on the one hand and between the sleeve and the stud on the other hand
Data Source
AI summary
The invention relates to an explosion-proof assembly (22) having an electrically conductive stud (23) made of a material which is not deformable radially. The stud (23) is coaxially surrounded in a central portion (23a) by an electrically insulating, electrically insulating sleeve (30). The sleeve (30) is in turn coaxially surrounded by a connecting portion (41) of a plastically deformable connecting body (40). Plastic deformation of the connecting portion (41) reduces the outer dimension thereof and the connecting portion (41) presses inwardly against the sleeve (30) to form a frictionally engaged form-fitting connection therebetween such that the connecting body (40), the sleeve (30) and the stud (23) form a structural unit with at least one stop surface (26) on the stud (23) resting against a counter stop surface of the sleeve (30).