Robot Joint Structure With Integrated Actuator Shafts

Solution Overview

Problem

The existing joint structure for robots with linear-motion actuators faces a trade-off between strength and size, as increasing the depth of the bearing member to enhance strength results in a thicker casing and larger robot size.

Innovation Solution

A joint structure that integrates a pair of first shaft parts with the outer surface of the casing, allowing the first link to pivot securely while reducing the casing thickness and robot size, by using a linear-motion actuator that couples the first link to the second link at a part separated from the joint part.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the depth of the through-hole is extended to fully secure the strength of the shaft part, then the strength is improved, but the thickness of the casing increases and the robot size increases

Engineering Contradiction:

Improvestrength of shaft partVSAvoidthickness of casing

Core Design Contradiction:

StrengthVSLength of stationary object

Solution Approach 1:

The bearing member is integrated with the shaft part to form a unified structure. The bearing member is formed in one piece with the shaft part, eliminating the need for a separate through-hole in the casing. This merging of components allows the shaft part to be supported by the bearing member's inherent structure rather than relying on the casing's wall thickness, thus maintaining strength while reducing casing thickness and overall robot size.

Inventive Principle:

Principle #5Merging (Combining)

2Strength

If the depth of the through-hole is extended to fully secure the strength of the shaft part, then the strength is improved, but the size of the robot increases

Engineering Contradiction:

Improvestrength of shaft partVSAvoidsize of robot

Core Design Contradiction:

StrengthVSVolume of moving object

Solution Approach 1:

The bearing member is integrated with the shaft part to form a unified structure. The bearing member is formed in one piece with the shaft part, eliminating the need for a separate through-hole in the casing. This merging of components allows the shaft part to be supported by the bearing member's inherent structure rather than relying on the casing's wall thickness, thus maintaining strength while reducing casing thickness and overall robot size.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11014251B2Joint structure for robot

Publication Date: 2021.05.25 KAWASAKI JUKOGYO KK

AI summary

A joint structure for a robot includes a first link and a second link rotatably coupled to each other through a joint part and a linear-motion actuator coupling the first link to the second link at a part separated from the joint part. The linear-motion actuator has a casing, and a pair of first shaft parts integrally formed with an outer surface of the casing. The first link is supported by the first shaft part so as to be pivotable with respect to the linear-motion actuator. The first link relatively pivots to the second link by the linear-motion actuator reciprocating.