Speed Reducer Main Bearing Structure for Heat and Rigidity

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Solution Overview

Problem

Conventional speed reducers face challenges in achieving both weight reduction and rigidity enhancement, often resulting in increased temperature issues that lead to deformation and malfunction due to the use of resin parts, which compromise strength and reliability.

Innovation Solution

The design incorporates an internal gear with a casing and outer pins, where one sliding surface is made of resin and the other of a thermally conductive material, with the outer pins positioned between the casing and external gear to improve rigidity and heat dissipation, while maintaining reduced size and weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If resin parts are used to reduce weight, then weight reduction is achieved, but strength and heat dissipation deteriorate

Engineering Contradiction:
ImproveweightVSAvoidstrength
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The patent applies composite materials by combining resin and metal in the main bearing structure. Specifically, the inner sliding surface is made of resin while the outer sliding surface is made of metal, creating a composite bearing that leverages the weight advantages of resin and the strength/heat dissipation advantages of metal. This resolves the contradiction by achieving weight reduction through resin usage while maintaining strength through metal components.

Inventive Principle:
Principle #40Composite materials

2Weight of moving object

If resin parts are used to reduce weight, then weight reduction is achieved, but heat dissipation deteriorates

Engineering Contradiction:
ImproveweightVSAvoidheat dissipation
Core Design Contradiction:
Weight of moving objectVSTemperature

Solution Approach 1:

The composite main bearing structure with resin inner sliding surface and metal outer sliding surface enables differentiated thermal management. The resin portion provides weight reduction while the metal portion provides superior heat dissipation. The combination allows the speed reducer to achieve both lightweight construction and effective heat dissipation simultaneously.

Inventive Principle:
Principle #40Composite materials

3Weight of moving object

If many resin parts are used to achieve weight reduction, then weight reduction is achieved, but reliability deteriorates

Engineering Contradiction:
ImproveweightVSAvoidreliability
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent uses composite materials in the main bearing to balance weight reduction and reliability. The resin component achieves weight reduction while the metal component ensures reliability through superior strength and wear resistance. This composite approach prevents the reliability deterioration that would result from using only resin parts.

Inventive Principle:
Principle #40Composite materials

4Strength

If outer pins are added to improve rigidity, then rigidity is improved, but device complexity increases

Engineering Contradiction:
ImproverigidityVSAvoiddevice complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent merges the outer pins with the main bearing structure, integrating the pin support function into the bearing assembly. This consolidation improves rigidity through the added pin support while avoiding the complexity increase that would result from completely separate pin mechanisms. The merged design achieves structural reinforcement without proportionally increasing device complexity.

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

This configuration effectively enhances the speed reducer's rigidity and heat dissipation, preventing failures and ensuring more reliable operation while achieving smaller size and lighter weight.

Implementation Method 1

the other of the inner and outer sliding surfaces is made of a thermally conductive material that is more wear-resistant than the resin

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

One of the inner and outer sliding surfaces is made of resin, and the other of a thermally conductive material that is more wear-resistant than the resin

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4040013A1Speed reducer
Publication Date: 2022.08.10 NABTESCO CORP
  • EP4040013A1 patent drawingFigure 1
  • EP4040013A1 patent drawingFigure 2
  • EP4040013A1 patent drawingFigure 3

AI summary

A speed reducer (100) relating to one aspect of the present invention includes: an internal gear (116) having a casing (122) and a plurality of outer pins (117), where the casing surrounds a main axis (1 La), and the outer pins are rotatably arranged in pin grooves (116b) provided on an inner periphery of the casing; an external gear (114) meshing with the internal gear; an eccentric body (112) for oscillating the external gear; a carrier (118, 120) rotatable relative to the casing; and a main bearing (124, 126) having an inner sliding surface (148) and an outer sliding surface (149), where the inner sliding surface is rotatable integrally with the casing, and the outer sliding surface is rotatable integrally with the carrier. One of the inner and outer sliding surfaces is made of resin, and the other of the inner and outer sliding surfaces is made of a thermally conductive material that is more wear-resistant than the resin.