Terminal Block Elastic Buffering for Thermal Stress
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Solution Overview
Problem
Terminal blocks with metal terminals housed in resin cases experience thermal stress due to differing coefficients of expansion, leading to potential cracking of insulating plates and reduced insulation reliability.
Innovation Solution
Incorporating plate-like resin members with higher elasticity between terminals and partition walls to buffer thermal stress, and optionally forming partition walls and case components separately to enhance insulation and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal terminals are housed in a resin case, then electrical connectivity and insulation are achieved, but thermal stress causes cracking of insulating plates due to differential expansion
Solution Approach 1:
A plate-like member made of elastomer is introduced as an intermediary between the metal terminal and the resin partition wall. This elastomeric intermediary absorbs thermal stress through its elasticity, preventing direct stress transmission that would cause cracking of the insulating partition wall while maintaining electrical insulation.
Solution Approach 2:
The patent changes the material parameter of the partition wall from rigid resin to a composite structure including an elastomeric layer. This material parameter change allows the partition system to accommodate thermal expansion differences between metal terminals and resin case, preventing stress-induced cracking.
2Reliability
If insulating plates are used to separate terminals, then electrical insulation is provided, but thermal stress from repeated temperature changes causes cracking
Solution Approach 1:
The patent incorporates a plate-like elastomeric member that functions as a flexible buffering layer between the rigid metal terminal and the resin partition wall. This flexible element accommodates thermal cycling stress through elastic deformation, preventing crack propagation in the insulating structure.
Solution Approach 2:
The elastomeric plate-like member is positioned in advance between the terminal and partition wall to cushion against upcoming thermal stress. This preemptive cushioning arrangement absorbs expansion/contraction forces before they can transmit to and crack the insulating partition wall.
3Stability of the object's composition
If terminals are fixed rigidly in the case, then structural stability is achieved, but thermal expansion causes stress concentration and potential failure
Solution Approach 1:
The patent changes the mechanical parameter of the interface between terminal and partition wall by introducing an elastomeric material. This material parameter change allows the system to maintain terminal positioning stability while accommodating thermal expansion through elastic deformation of the elastomeric layer.
Solution Approach 2:
The elastomeric plate-like member introduces dynamic flexibility to the terminal mounting system. Instead of rigid fixed positioning, the elastomeric material allows controlled movement and deformation in response to thermal expansion, distributing stress dynamically rather than concentrating it at fixed points.
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
Prevents cracking of partition walls and case components, maintaining insulation reliability and facilitating heat dissipation by using elastic resin members and separate component formations.
Implementation Method 1
plate-like members provided between the partition wall and the terminals and made of a material with a higher elasticity than the case and the partition wall
Implementation Method 2
thermal stress is created in an insulating plate made of an insulating resin between the terminals due to a temperature change since there is a difference in linear coefficient of expansion between the metal and the resin
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A terminal block for electrically connecting a plurality of first wires connected to an electric motor and a plurality of second wires connected to a power conversion device for supplying drive power of the electric motor includes a case, a plurality of terminals housed in the case and configured to connect the plurality of first wires and the plurality of second wires to each other, a partition wall provided between the plurality of terminals to electrically isolate the plurality of terminals from each other, and plate-like members provided between the partition wall and the terminals and made of a material with a higher elasticity than the case and the partition wall.