Sealed Speed Reducer Assembly for Compact Maintenance Access

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Solution Overview

Problem

Existing power transmission devices with speed reducers, like those in industrial machinery, face challenges in maintaining a compact design while allowing for easy maintenance without the need to drain lubricants, as they often require adapters that increase the overall length and complexity.

Innovation Solution

A power transmission device and speed reducer design that seals the interior using a shaft seal portion, casing seal portion, and end cover, allowing the motor to be connected directly without an adapter, reducing the overall length and facilitating maintenance by eliminating the need for lubricant drainage during disassembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If an adapter is used to fix the motor to the base member and serve as the lubricant-filled space, then the motor can be connected to the speed reducer, but the overall length of the machine is increased

Engineering Contradiction:
Improveoverall length of the machineVSAvoidstructure complexity
Core Design Contradiction:
Length of moving objectVSDevice complexity

Solution Approach 1:

The patent merges the adapter function with the speed reducer housing by making the adapter an integral part of the reducer structure. The adapter is formed as a unified component with the housing, eliminating the need for separate adapter parts and reducing overall assembly complexity while maintaining the lubricant containment function.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The speed reducer housing serves multiple functions: it contains the lubricant, provides structural support, and integrates the motor mounting adapter function. This multi-functionality eliminates the need for separate dedicated adapter components, thereby reducing overall device length and complexity.

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

2Ease of repair

If the speed reducer is separated from the driven member for maintenance while the speed reducer remains connected to the motor, then maintenance work is facilitated, but the lubricant must be drained to the outside

Engineering Contradiction:
Improvemaintenance easeVSAvoidlubricant loss
Core Design Contradiction:
Ease of repairVSLoss of substance

Solution Approach 1:

The patent segments the speed reducer into modular components that can be independently removed for maintenance. The carrier assembly can be separated from the housing while the housing retains the lubricant, allowing maintenance work on the carrier without draining or losing the lubricant contained in the housing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The housing acts as an intermediary lubricant containment chamber that remains connected to the motor during maintenance operations. This intermediary structure allows the carrier to be removed and serviced while the housing maintains the lubricant seal, preventing lubricant loss during maintenance.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If multiple sealing locations are provided in the speed reducer, then lubricant leakage is prevented, but the manufacturing complexity increases

Engineering Contradiction:
Improvesealing reliabilityVSAvoidmanufacturing ease
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines multiple sealing functions into integrated sealing structures. The seals at different locations are designed as coordinated components that work together as a unified sealing system, reducing the number of separate sealing parts and simplifying manufacturing while maintaining comprehensive sealing reliability.

Inventive Principle:
Principle #5Merging (Combining)

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 the overall length of the device with the motor connected and simplifies maintenance by maintaining a sealed system, enabling easy removal and replacement of components without lubricant leakage.

Implementation Method 1

a shaft seal portion sealing a space between the through hole and the input shaft

Methodology Applied
Scientific EffectSealing: Physical Containment

Implementation Method 2

a casing seal portion sealing a space between the casing and an outer peripheral surface of the output rotating body

Methodology Applied
Scientific EffectSealing: Physical Containment

Data Source

PatentEP4528126A1Power transmission device, speed reducer, industrial machine, and method of disassembling industrial machine for maintenance
Publication Date: 2025.03.26 NABTESCO CORP
  • EP4528126A1 patent drawingFigure 1
  • EP4528126A1 patent drawingFigure 2
  • EP4528126A1 patent drawingFigure 3

AI summary

The present invention relates to a power transmission device, a speed reducer (12), and a method of disassembling an industrial machine for maintenance. The power transmission device includes a casing (13), output rotating body (14A, 14B), input shaft (30), power transmission mechanism (15, 16A, 16B, 26), shaft seal portion (70), casing seal portion (44), and end cover (34). The casing (13) is fixed to the base member (2). The output rotating body (14A, 14B) is rotatably housed inside the casing (13). The output rotating body (14A, 14B) has a first connecting portion (14N) that is to be connected to a connected member (3). The input shaft (30) is connected to a rotating shaft (11a) of a motor (11). The power transmission mechanism (15, 16A, 16B, 26) is disposed in the casing while surrounded by the output rotating body (14A, 14B) and transmits rotation of the input shaft (30) to the output rotating body (14A, 14B). The shaft seal portion (70) seals a space between a through hole of the output rotating body (14A, 14B) and the input shaft (30). The casing seal portion (44) seals a space between the casing (13) and the outer peripheral surface of the output rotating body (14A, 14B). The end cover (34) is attached to the first connecting portion (14N) of the output rotating body (14A, 14B).