Compressor Terminal Rod Crimping for Low Resistance

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Solution Overview

Problem

Conventional methods for connecting electric wires to terminal rods in compressors result in increased electric resistance and potential burnout due to inadequate conductivity and air pressure issues, leading to contact resistance problems.

Innovation Solution

A motor design featuring a terminal rod with a crimping portion, a concave part, and a communication part, where the electric wires are crimped into the concave part of the terminal rod, reducing electric resistance and preventing wire dislodgment by allowing air pressure release through the communication part, with a seal member and terminal base providing corrosion and pressure resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electric wires are connected to terminal rod using conventional welding method through cutout portion, then connection is achieved, but electric resistance increases and conductivity deteriorates

Engineering Contradiction:
Improveconnection reliabilityVSAvoidelectric resistance
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The terminal rod is divided into functionally distinct segments: a crimping portion for mechanical connection and a fitting hole portion for electrical connection. This segmentation allows each portion to be optimized for its specific function, preventing the compromise that occurs when a single structure must serve both purposes simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A separate crimping portion acts as an intermediary component between the electric wire and the terminal rod's fitting hole. The wire is first crimped to this intermediate structure, which then connects to the terminal rod, ensuring both mechanical strength and electrical conductivity without the defects of direct welding through cutout portions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If core wire is inserted into fitting hole and welded, then connection is formed, but aluminum wires and terminal main body are insufficiently combined at inner circumference

Engineering Contradiction:
Improveconnection processVSAvoidcombination strength
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The terminal rod is divided into functionally distinct segments: a crimping portion for mechanical connection and a fitting hole portion for electrical connection. This segmentation allows each portion to be optimized for its specific function, preventing the compromise that occurs when a single structure must serve both purposes simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The crimping portion applies excessive radial pressure beyond what is minimally required for connection, ensuring that the electric wire is thoroughly and uniformly combined with the terminal rod structure. This over-compression guarantees sufficient contact area and mechanical strength at the connection interface.

Inventive Principle:
Principle #16Partial or excessive action

3Strength

If full-circumferential crimping is applied to connect wire, then mechanical connection is strong, but air pressure increases in closed space causing wire to drop off

Engineering Contradiction:
Improvemechanical connection strengthVSAvoidconnection stability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The harmful air pressure effect is extracted or removed from the connection system by providing a communication passage that connects the crimping portion's internal space to the external environment. This allows the air pressure that would otherwise build up and push the wire out to be vented away, maintaining the crimping force.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The communication passage is pre-formed in the terminal rod structure before the crimping operation. This preliminary provision of an air escape route ensures that when crimping is applied, the air can immediately escape without building up pressure that would compromise the connection stability.

Inventive Principle:
Principle #10Preliminary action

4Reliability

If terminal structure provides strong wire connection, then conductivity improves, but sealed structure and corrosion resistance may be compromised

Engineering Contradiction:
ImproveconductivityVSAvoidcorrosion and sealing
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A seal member acts as an intermediary element between the terminal rod and the motor casing, creating a barrier that prevents corrosive refrigerant from reaching the electrical connection components. This intermediary sealing structure protects the conductivity-providing portions from corrosion while maintaining the sealed enclosure.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The terminal assembly is segmented into functionally distinct portions: the crimping and fitting portions for electrical connection, and the seal portion for environmental protection. This segmentation allows the connection portions to be optimized for conductivity while the seal portion independently provides corrosion protection.

Inventive Principle:
Principle #1Segmentation

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 reduces electric resistance between the wires and terminal rod, prevents wire dislodgment, and maintains a sealed structure, ensuring reliable operation and corrosion resistance.

Implementation Method 1

the outer surface of the crimping portion is pressurized so that a plurality of the electric wires are fixed to the crimping portion

Methodology Applied
Scientific EffectPressurizing: Pressure Increase

Implementation Method 2

a communication part providing communication between an outer surface of the crimping portion and the concave part... allowing air pressure release through the communication part

Methodology Applied
Scientific EffectPressure equalization: Pressure Gradient

Implementation Method 3

with a seal member disposed along the seal portion... providing corrosion and pressure resistance

Methodology Applied
Scientific EffectCorrosion resistance:

Data Source

PatentEP2251958B1Motor and compressor with the same
Publication Date: 2019.09.25 KOBE STEEL LTD
  • EP2251958B1 patent drawingFigure 1
  • EP2251958B1 patent drawingFigure 2
  • EP2251958B1 patent drawingFigure 3

AI summary

In a motor, one ends of a plurality of electric wires with the other ends connected to the motor side are connected to a terminal rod, and the terminal rod is exposed to the exterior of a motor casing via a terminal base. The terminal rod is provided with a flange portion and a crimping portion. A concave part is formed on an end surface of the crimping portion, and a communication part providing communication between an outer surface and the concave part is formed. The terminal base is provided with a depression to be fitted to the flange portion of the terminal rod, a seal portion having a diameter reduced from the depression, and a through portion pasting from the seal portion through to the exterior of the motor casing. A seal member is put on the terminal rod. In a state that the electric wires are inserted into the concave part of the crimping portion, the outer surface of the crimping portion is pressurized, so that the electric wires are fixed to the crimping portion. With such a configuration, it is possible to reduce electric resistance between the electric wires from the motor side and the terminal rod and strongly combine the electric wires and the terminal rod.