Integrated Speed Reducing Device with Dual Cycloid Discs

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Solution Overview

Problem

Conventional speed reducing devices with separate motor and reducer components increase volume and weight, making them unsuitable for lightweight and compact applications, and mono-cycloidal reducers suffer from dynamic balance issues at high speeds.

Innovation Solution

A speed reducing device integrating a motor and a speed reducing mechanism as a single unit, utilizing a two-stage cycloid reducer with a radial-flux motor and eccentric rings to achieve high rigidness and dynamic balance without the need for additional connection structures like shaft couplings or gearboxes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If separate motor and reducer components are used with connection structures, then the components can be independently manufactured and maintained, but the overall volume and weight of the device increase

Engineering Contradiction:
ImproveIndependent manufacturingVSAvoidOverall weight
Core Design Contradiction:
Ease of manufactureVSWeight of stationary object

Solution Approach 1:

The patent combines the motor and reducer into a single integrated unit where the motor rotor serves as the reducer input and the motor housing serves as the reducer output housing. This merging eliminates the need for separate connection structures like shaft couplings, thereby reducing overall weight and volume while maintaining manufacturability through modular assembly of the integrated components

Inventive Principle:
Principle #5Merging (Combining)

2Ease of manufacture

If separate motor and reducer components are used with connection structures, then the components can be independently manufactured and maintained, but the overall volume of the device increases

Engineering Contradiction:
ImproveIndependent manufacturingVSAvoidOverall volume
Core Design Contradiction:
Ease of manufactureVSVolume of moving object

Solution Approach 1:

The motor and speed reducing mechanism are merged into a single integrated structure where the motor housing double-acts as the reducer output housing. This eliminates the need for separate connection structures and reduces the overall volume of the device while maintaining independent manufacturability of the integrated components

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If a mono-cycloidal set is used in the speed reducing mechanism, then the device structure is simplified, but dynamic balance cannot be maintained at high speeds resulting in high vibration

Engineering Contradiction:
ImproveReducer structureVSAvoidVibration
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent employs a dual cycloid disc set configuration where two cycloid discs operate in parallel with opposite eccentricity directions. This counterbalancing arrangement generates equal and opposite centrifugal forces that cancel each other out, eliminating vibration and maintaining dynamic balance at high speeds while preserving structural simplicity

Inventive Principle:
Principle #8Anti-weight (Counterweight)

4Weight of stationary object

If the motor and speed reducing mechanism are integrated without connection structures, then weight and volume are reduced, but the design complexity increases

Engineering Contradiction:
ImproveOverall weightVSAvoidIntegrated design
Core Design Contradiction:
Weight of stationary objectVSDevice complexity

Solution Approach 1:

The motor housing serves multiple functions: it acts as both the motor stator housing and the reducer output housing. The motor rotor serves as both the motor rotating component and the reducer input. This multi-functionality reduces weight and eliminates connection structures while managing design complexity through functional integration rather than structural complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 integrated design reduces volume and weight, enhances dynamic balance, and allows for high-load operation with a high reduction ratio, making it suitable for applications like industrial robotic arms and power assisting devices.

Implementation Method 1

The motor includes a stator portion and a rotor portion. The rotor portion is rotated relative to the stator portion.

Methodology Applied
Scientific EffectElectromagnetic interaction: Electromagnetic Induction

Implementation Method 2

The first eccentric ring and the second eccentric ring are disposed beside each other and disposed on an inner surface of the rotor casing assembly

Methodology Applied
Scientific EffectEccentric rotation: Eccentric

Implementation Method 3

The first cycloid disc set is mounted around the output shaft and disposed within the first eccentric ring. The first cycloid disc set includes a plurality of first tooth structures and a plurality of second tooth structures

Methodology Applied
Scientific EffectCycloid gear mechanism: Gear

Implementation Method 4

The at least one first roller is contacted with at least one of the plurality of first tooth structures. The at least one second roller is contacted with at least one of the plurality of third tooth structures

Methodology Applied
Scientific EffectRolling contact: Roller

Data Source

PatentEP3480924B1Speed reducing device having power source
Publication Date: 2020.07.22 DELTA ELECTRONICS INC(CN)
  • EP3480924B1 patent drawingFigure 1
  • EP3480924B1 patent drawingFigure 2
  • EP3480924B1 patent drawingFigure 3

AI summary

A speed reducing device (1, 1') includes a motor (2) and a speed reducing mechanism (3). The motor (2) includes a stator portion (20) and a rotor portion (21). The rotor portion (21) includes a first eccentric ring (211) and a second eccentric ring (212). The speed reducing mechanism (3) is partially accommodated within the rotor portion (21). The speed reducing mechanism (3) includes a first roller assembly (32), a second roller assembly (33), a third roller assembly (34), a first cycloid disc set (30, 30') and a second cycloid disc set (31, 31'). The first roller assembly (32) includes at least one first roller (321). The second roller assembly (33) includes at least one second roller (331). The third roller assembly (34) includes an output shaft and at least one third roller (341). The first cycloid disc set (30, 30') is mounted around the output shaft (340) and disposed within the first eccentric ring (211). The second cycloid disc set (31, 31') is mounted around the output shaft (340) and disposed within the second eccentric ring (212).