Terminal Holder Arrangement for Compact Drive Device

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Solution Overview

Problem

Conventional driving apparatus designs experience an increase in size in the radial direction of the rotating shaft due to the arrangement of the terminal holder along the tangential direction of the rotating shaft.

Innovation Solution

The driving apparatus incorporates a terminal holder with a projecting portion and terminal holding slots arranged along the circumference, allowing the terminals to be positioned at intervals on the same circumference, preventing an increase in size by optimizing the assembly and ensuring the terminals are connected without interfering with other components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the terminal holder is arranged along the tangential direction of the rotating shaft, then the terminals can be connected to the electric motor, but the driving apparatus increases in size in the radial direction of the rotating shaft

Engineering Contradiction:
Improveterminal connectionVSAvoidradial size
Core Design Contradiction:
Ease of manufactureVSLength of stationary object

Solution Approach 1:

The terminal holder is repositioned from a tangential arrangement (radial dimension) to an axial arrangement along the rotating shaft (axial dimension). This dimensional transition allows terminals to be connected effectively while preventing increase in radial size, as the terminals now extend in the axial direction rather than consuming radial space.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Length of stationary object

If the terminal holder is positioned inside the rotating shaft, then the radial size is reduced, but the terminals may interfere with other components in the gear case

Engineering Contradiction:
Improveradial sizeVSAvoidcomponent interference
Core Design Contradiction:
Length of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The terminal holder is positioned at a specific location inside the gear case where it does not interfere with other components. The holding slots are arranged to face the rotating shaft while maintaining sufficient clearance from the worm, worm gear, and control board. This localized positioning achieves compact radial dimensions while avoiding harmful interference with adjacent components.

Inventive Principle:
Principle #3Local quality

3Reliability

If the terminal holder is fixed to the gear case, then the terminals are securely connected, but the assembly complexity increases

Engineering Contradiction:
Improveterminal connection stabilityVSAvoidassembly process
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The terminal holder is integrated with the gear case as a single unit rather than being a separate component. This merging eliminates the need for additional fastening operations between the terminal holder and gear case, reducing assembly complexity while maintaining secure terminal connections through the unified structure.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3214738B1Drive device
Publication Date: 2021.05.19 MITSUBA CORP
  • EP3214738B1 patent drawingFigure 1
  • EP3214738B1 patent drawingFigure 2
  • EP3214738B1 patent drawingFigure 3

AI summary

A driving apparatus having an electric motor configured to rotate a rotating shaft (27) by a supplied current, the driving apparatus comprising: a control board (49) which is positioned relative to the electric motor, and on which electronic components for controlling the electric motor is mounted; a plurality of first terminals (58, 59, 60) which are mounted on the control board (49), the first terminals (58, 59, 60) carrying a current; a plurality of second terminals (44, 45, 46) connected to the respective first terminals (58, 59, 60), the second terminals (44, 45, 46) carrying a current, the second terminals (44, 45, 46) being disposed outside the rotating shaft (27) in a radial direction of the rotating shaft (27) and arranged along a circumferential direction of the rotating shaft (27).