Speed Reducer Output Structure for Low Inertia and Damage Prevention

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Solution Overview

Problem

Existing speed reducers face challenges in reducing the moment of inertia of internal mechanisms and preventing damage between members due to differences in material hardness, which affects connection accuracy between the output and driven members.

Innovation Solution

A speed reducer design incorporating a lightweight first member with lower specific gravity and hardness than the internal and external gears, and a protection member with higher hardness than the first member, to reduce moment of inertia and prevent damage during connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If a lightweight material (lower specific gravity) is used for the first member, then the moment of inertia of the internal mechanism is reduced, but the hardness of the first member becomes lower than the driven member, causing damage during connection

Engineering Contradiction:

Improvemoment of inertiaVSAvoiddamage prevention

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

A protection member is introduced as an intermediary component between the first member (lightweight output member) and the driven member. This protection member has hardness higher than the first member, acting as a mediator that prevents direct contact and potential damage between the lightweight first member and the harder driven member, while allowing the first member to maintain its lightweight advantage

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The speed reducer employs a composite material strategy where the first member is made of a lightweight material (lower specific gravity than steel gears) while the protection member is made of a harder material. This composite approach allows different parts of the system to have optimized properties: lightweight for inertia reduction where needed, and hard for protection where contact occurs

Inventive Principle:

Principle #40Composite materials

2Weight of moving object

If a lightweight material (lower specific gravity) is used for the first member, then the moment of inertia of the internal mechanism is reduced, but the connection accuracy between the output and driven members deteriorates due to hardness differences

Engineering Contradiction:

Improvemoment of inertiaVSAvoidconnection accuracy

Core Design Contradiction:

Weight of moving objectVSManufacturing precision

Solution Approach 1:

The protection member serves as a mediator that interfaces between the lightweight first member and the driven member. By having hardness higher than the first member, it ensures that during connection and operation, the protection member rather than the first member undergoes wear or deformation, thereby maintaining connection accuracy between the output and driven members while preserving the lightweight design

Inventive Principle:

Principle #24Intermediary (Mediator)

3Weight of moving object

If the hardness of the first member is made lower than the driven member, then the moment of inertia is reduced through lightweight material, but damage occurs during connection between members

Engineering Contradiction:

Improvemoment of inertiaVSAvoidresistance to damage

Core Design Contradiction:

Weight of moving objectVSStrength

Solution Approach 1:

The protection member acts as a protective intermediary with hardness higher than the first member. It absorbs the mechanical stress and potential damage during connection operations, shielding the lightweight first member from damage while allowing the first member to maintain its low-density, low-inertia characteristics

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The protection member is installed in advance between the first member and the driven member to provide beforehand cushioning and protection. This preventive measure ensures that when connection or operational stresses occur, the protection member is already in place to prevent damage to the lightweight first member, rather than waiting for damage to occur

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentUS11493112B2Speed reducer

Publication Date: 2022.11.08 SUMITOMO HEAVY IND LTD

AI summary

A speed reducer includes a reduction mechanism, which includes an internal gear and an external gear meshing with the internal gear, and a first member, and transmits rotating motion decelerated by the reduction mechanism to a driven member. The speed reducer includes a protection member disposed between the first member and the driven member. The first member is formed of a material having specific gravity lower than at least one of the internal gear and the external gear and hardness lower than the driven member. The protection member is formed of a material having hardness higher than the first member.