Gear Motor Detector Layout Without a Hollow Shaft

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Solution Overview

Problem

The existing gear motors with integrated motor and reduction gear structures face challenges in accommodating both a first detector for the motor shaft rotation and a second detector for the output shaft rotation due to space constraints, leading to a complicated structure.

Innovation Solution

The gear motor design integrates the motor and reduction gear side by side along the motor shaft, with detection units positioned between the motor and the second carrier member, eliminating the need for a hollow motor shaft and allowing direct detection of shaft and carrier member rotations, thereby simplifying the structure and reducing size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the motor shaft is formed as a hollow shaft and the output shaft passes through it, then both first detector and second detector can be disposed on one side, but the structure becomes complicated

Engineering Contradiction:
Improvedetector arrangementVSAvoidstructure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent transitions from a one-sided detector arrangement (requiring hollow shaft) to a two-sided arrangement where detectors are disposed on both sides of the motor shaft. This dimensional change in spatial configuration eliminates the need for hollow shaft structure while achieving the same detection functionality, thereby simplifying the overall structure.

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

Solution Approach 2:

The patent divides the detector arrangement into two separate locations: one detector on each side of the motor shaft. This segmentation allows each detector to be independently mounted on solid shaft surfaces without requiring complex hollow shaft structures, simplifying both the shaft design and detector mounting.

Inventive Principle:
Principle #1Segmentation

2Volume of moving object

If detectors are disposed on one side of the motor, then space is saved, but the structure becomes complicated requiring hollow shaft

Engineering Contradiction:
ImprovespaceVSAvoidstructure
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent utilizes both sides of the motor shaft (two-dimensional spatial utilization) to mount detectors, rather than concentrating both detectors on one side. This approach eliminates the need for hollow shaft while maintaining compact space utilization, resolving the contradiction between space efficiency and structural simplicity.

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

3Volume of moving object

If motor and reduction gear are connected side by side, then compact structure is achieved, but space for detectors is limited

Engineering Contradiction:
ImprovesizeVSAvoiddetector mounting space
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The patent segments the detector mounting locations to opposite sides of the motor shaft, utilizing the space on both sides of the compact motor-reduction gear assembly. This segmentation approach allows detectors to be mounted without requiring additional space in the already compact configuration, maintaining small overall size while enabling detector installation.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3889462B1Gear motor
Publication Date: 2026.03.04 SUMITOMO HEAVY IND LTD
  • EP3889462B1 patent drawingFigure 1
  • EP3889462B1 patent drawingFigure 2
  • EP3889462B1 patent drawingFigure 3

AI summary

The structure of a gear motor (1, 1A, 1B) is simplified. In a gear motor (1, 1A, 1B) including a motor (20, 20A, 20B) and a reduction gear (30), the reduction gear (30) includes a reduction mechanism (33) and a carrier member (32) to which rotation decelerated by the reduction mechanism (33) is transmitted, the carrier member (32) includes a first carrier member (321) that is disposed on a motor opposite side of the reduction mechanism (33) and a second carrier member (322) that is disposed on a motor side of the reduction mechanism (33) and is connected to the first carrier member (321), the gear motor (1, 1A, 1B) includes a first detection unit (80) that detects a rotation of the motor (20, 20A, 20B) and a second detection unit (90) that detects a rotation of the carrier member (32), and the second detection unit (90) is disposed between the motor (20, 20A, 20B) and the second carrier member (322).