Hazardous Environment Motor with Internal Tie Bars
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Solution Overview
Problem
Conventional electric motors for hazardous environments have complex exterior geometries that complicate cleaning, particularly in hygienic environments like food and pharmaceutical industries, and do not effectively manage internal explosion forces due to external tie bolts and complex terminal box designs.
Innovation Solution
The electric motor features internal tie bars instead of external tie bolts and a simplified cylindrical terminal box design, made from stainless steel, to reduce exterior complexity and internal free volume, enhancing cleaning capabilities and explosion resistance without increasing the motor's size or component strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If external tie bolts are used to secure the housing, then the motor can be assembled, but the exterior geometry becomes complex and difficult to clean
Solution Approach 1:
The patent removes external tie bolts from the motor housing and replaces them with internal tie bars that are concealed within the housing structure. This extraction of the fastening elements from the exterior eliminates the complex external geometry while maintaining the structural integrity and assembly capability of the housing.
Solution Approach 2:
The tie bars are nested within the housing interior, with their ends extending into recesses in the end caps. This nesting arrangement conceals the fastening elements inside the housing structure, eliminating external protrusions while maintaining the structural connection between housing components.
2Ease of operation
If internal tie bars are used instead of external bolts, then cleaning is easier, but the free volume inside the housing decreases
Solution Approach 1:
The tie bars are positioned in the radial dimension of the housing, extending from the end caps toward the center but terminating in recesses before reaching the middle. This dimensional arrangement allows the fastening structure to occupy minimal axial and radial space while maintaining structural integrity, preserving maximum internal free volume.
Solution Approach 2:
The tie bars are designed with varying cross-sectional areas along their length, with larger dimensions at the anchored ends and smaller dimensions in the intermediate sections. This local quality variation optimizes the structural strength where needed while minimizing the volume occupied by the fastening elements in the critical internal space.
3Adaptability or versatility
If the terminal box has complex geometry for electrical connections, then functionality is improved, but the exterior becomes harder to clean
Solution Approach 1:
The patent extracts the electrical connection functionality from the external terminal box geometry and relocates it to an internal flange structure on the housing. This extraction eliminates the need for complex external terminal box features while maintaining full electrical connection capability through internal mounting surfaces and conduit entries.
4Ease of manufacture
If the motor housing is enlarged to accommodate internal tie bars, then assembly is possible, but the free volume for vapor accumulation increases
Solution Approach 1:
The tie bars are designed with flexible mounting arrangements that allow them to accommodate manufacturing tolerances and assembly variations without requiring precise housing dimensions. The recesses in the end caps provide tolerance compensation, enabling assembly with standard housing sizes while minimizing internal volume occupation.
Data Source
AI summary
An electric motor is provided that is configured for operation in hazardous or other hazardous environments. The electric motor includes a housing for a rotor and a stator. The housing includes a pair of end caps and a casing positioned therebetween. The end caps and the casing are held together using internal tie bars extending between and connected to the end caps.