Composite Gear Structure for Low Weight and High Strength

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Solution Overview

Problem

Existing gears face challenges in achieving weight reduction while maintaining high strength, especially in applications where high loads are encountered, such as in industrial robots and automobiles.

Innovation Solution

The gear is designed with a metal outer peripheral portion and a metal central portion, with a resin portion connecting them. This configuration reduces weight while maintaining strength by utilizing the high strength of metal in critical areas and the lighter resin in other portions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If a resin material is used for the gear, then the weight can be reduced, but the strength of the gear becomes low

Engineering Contradiction:
Improveweight of gearVSAvoidstrength of gear
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The gear is constructed using a composite structure where a metal outer peripheral portion (providing strength) and a metal central portion are combined with a resin portion. This composite material approach allows the gear to achieve both weight reduction from the resin and high strength from the metal components, directly resolving the contradiction between weight reduction and strength maintenance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Different portions of the gear are assigned different materials based on their functional requirements: the outer peripheral portion with teeth uses metal for high strength and wear resistance, while the central portion uses resin for weight reduction. This local differentiation of material properties allows the gear to optimize both weight and strength in different regions simultaneously.

Inventive Principle:
Principle #3Local quality

2Strength

If a metal gear is used, then the strength is high, but the weight increases

Engineering Contradiction:
Improvestrength of gearVSAvoidweight of gear
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The gear employs a composite structure combining metal and resin materials. The metal outer peripheral portion and central portion provide the necessary strength, while the resin portion reduces the overall weight. This composite approach directly addresses the contradiction by maintaining high strength through metal components while achieving weight reduction through the resin material.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The gear structure differentiates material usage by region: metal is used in the outer peripheral portion and central portion where strength is critical, while resin is used in portions where weight reduction is prioritized. This local quality differentiation resolves the contradiction between high strength and weight reduction by optimizing material placement according to functional requirements.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3667124B1Gear component
Publication Date: 2025.05.28 MITAKA DENSHI CO LTD
  • EP3667124B1 patent drawingFigure 1~2
  • EP3667124B1 patent drawingFigure 3~4
  • EP3667124B1 patent drawingFigure 5~6

AI summary

There is provided a gear component which is used for the production of a gear which is lightweight while having an appropriate strength. The gear component has an annular form and is made of a metal, comprising tooth portions 5 and a support portion 8 which supports the tooth portions, wherein a plurality of the tooth portions are provided on an outside of the support portion 8 along its entire circumference, a plurality of groove portions 12 are provided along a width direction of the gear evenly on an annular inner surface of the support portion, the groove portions are present such a ratio that at least one groove portion is provided per one tooth portion or adjacent two or more tooth portions, and each groove portion is formed such that it is located to correspond to a position where the tooth portion is present on the supporting portion.