Speed Reducer Snap-Fit Coupling for Bolt-Free Assembly

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Solution Overview

Problem

The assembly and disassembly of speed reducers made of resin or similar materials for reducing size and weight are complicated due to the need for bolts and mating members, which complicates the connection process.

Innovation Solution

A speed reducing mechanism that utilizes a coupling member with an elastic deformation portion and a claw portion to couple the case and mating member via a snap-fit structure, eliminating the need for bolts, allowing for efficient assembly and disassembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If speed reducers are made of resin to reduce size and weight, then weight is reduced, but assembly process becomes complicated due to bolt strength requirements

Engineering Contradiction:
Improveweight of speed reducerVSAvoidassembly process complexity
Core Design Contradiction:
Weight of moving objectVSDevice complexity

Solution Approach 1:

The patent replaces the traditional mechanical bolt fastening system with an elastic coupling member system. The elastic deformation portion deforms elastically to provide coupling force, substituting the need for bolts and their associated strength calculations and complex assembly procedures.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the material parameter from rigid (metal bolts) to elastic (resin or elastic material). The elastic deformation portion is made of resin or similar elastic material that can deform within elastic limits to provide the necessary coupling force, simplifying the assembly process while maintaining connection strength.

Inventive Principle:
Principle #35Parameter changes

2Weight of moving object

If speed reducers are made of resin to reduce size and weight, then weight is reduced, but assembly and disassembly work becomes complicated

Engineering Contradiction:
Improveweight of speed reducerVSAvoidassembly and disassembly time
Core Design Contradiction:
Weight of moving objectVSLoss of time

Solution Approach 1:

The patent replaces the time-consuming bolt fastening and unfastening operations with a simple elastic coupling mechanism. The elastic deformation portion naturally deforms to engage and disengage, eliminating the need for tools and complex procedures, thereby reducing assembly and disassembly time.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The elastic coupling member performs self-service by using its own elastic deformation to achieve coupling and decoupling. The elastic deformation portion deforms under insertion force to engage the coupling, and can be easily released by applying force in the opposite direction, making the assembly and disassembly process self-sufficient and tool-free.

Inventive Principle:
Principle #25Self-service

3Strength

If traditional bolt fastening is used to connect case and mating member, then connection strength is sufficient, but assembly process is complicated

Engineering Contradiction:
Improveconnection strengthVSAvoidassembly process complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent changes the connection mechanism from rigid mechanical fastening to elastic deformation-based coupling. The elastic deformation portion is designed with appropriate elastic limits and deformation characteristics to provide sufficient coupling force while simplifying the assembly process, eliminating the need for bolt strength calculations and complex fastening procedures.

Inventive Principle:
Principle #35Parameter changes

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 simplifies the assembly and disassembly process by eliminating the need for fastening with bolts, thereby improving work efficiency.

Implementation Method 1

an elastic deformation portion extending in the axial direction along the axis and capable of elastic deformation in a radial direction intersecting the axial direction

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4249175B1Speed reducing mechanism and robot
Publication Date: 2025.08.06 NABTESCO CORP
  • EP4249175B1 patent drawingFigure 1
  • EP4249175B1 patent drawingFigure 2
  • EP4249175B1 patent drawingFigure 3

AI summary

A rotation mechanism (1A, 1B, 1C) according to the invention includes: an output portion for outputting, to a mating member (112), rotation of a drive source (107, 108, 109) producing a rotational force; a coupling member (30, 130) for coupling the mating member (112) and the output portion by elastic deformation; and an anti-rotation portion for preventing relative rotation between the mating member (112) and the output portion.