Electric Motor Terminal Axial Overlap for Steering Reliability

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Solution Overview

Problem

Conventional electric driving devices for power steering systems require additional space and components for electrical connections, leading to increased costs and reliability issues due to loose screws from vibrations and heat cycles.

Innovation Solution

The motor and output terminals are formed to extend parallel to the axial direction of the electric motor, overlapping and laser-welded for reduced size, cost, and enhanced reliability, eliminating the need for screws and reducing the space required for connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If motor terminals and winding terminals are screwed together for electrical connection, then electrical connection is achieved, but device size increases and costs increase due to additional space requirements and screw components

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoiddevice size
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The motor terminal and winding terminal are merged into a single integrated structure where the motor terminal is directly formed as an extension of the winding terminal. This eliminates the need for separate screw connections and reduces the space required for electrical connections, directly resolving the contradiction between connection reliability and device size.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The screw fastening mechanism is extracted and removed from the electrical connection system. By eliminating the screw and its required clearance space, the device size is reduced while maintaining electrical connection through the integrated terminal structure.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If motor terminals and winding terminals are screwed together, then electrical connection is achieved, but costs increase due to additional parts

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidnumber of parts
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The motor terminal and winding terminal are merged into a single integrated structure, eliminating the screw as a separate component. This reduces the total number of parts and simplifies the assembly process, directly addressing the contradiction between connection reliability and device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The screw fastening mechanism is extracted and removed from the system. By eliminating this additional part, the device complexity is reduced while electrical connection is maintained through the integrated terminal design.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If screws are used for electrical connection, then connection is achieved, but reliability deteriorates due to loose screws from vibration and heat cycles

Engineering Contradiction:
Improveassembly easeVSAvoidelectrical connection reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The screw fastening mechanism is extracted and removed from the electrical connection system. By eliminating the screw, the source of vibration-induced loosening and heat cycle degradation is removed, significantly improving connection reliability while maintaining assembly simplicity through the integrated terminal structure.

Inventive Principle:
Principle #2Taking out (Extraction)

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

This configuration achieves a reduction in device size, improves workability, decreases electrical resistance, and enhances the reliability and waterproofing of the electrical connection, while eliminating the need for screws, thus lowering costs and improving performance.

Implementation Method 1

overlapping and laser-welded for reduced size, cost, and enhanced reliability

Methodology Applied
Scientific EffectLaser welding: Laser Beam Welding

Data Source

PatentEP2549627B1Electric drive device and electric power steering device having same mounted therein
Publication Date: 2020.06.03 MITSUBISHI ELECTRIC CORP
  • EP2549627B1 patent drawingFigure 1
  • EP2549627B1 patent drawingFigure 2
  • EP2549627B1 patent drawingFigure 3(a)~3(b)

AI summary

Reduction in costs and size of an electric driving device is achieved and reliability of electrical connection thereof is enhanced. The device comprises: an electric motor; a controller that is disposed coaxially with the axis of the electric motor rotation shaft and takes control of driving the electric motor; a motor terminal whose end extends from the electric motor toward the controller; and an output terminal whose end extends from the controller toward the electric motor; wherein a portion of the motor terminal including the end thereof and that of the output terminal including the end thereof each are formed to extend in parallel to an axial direction of the electric motor, and overlappingly connected with each other.