Robot Arm Drive Mechanism Motor Relocation

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Solution Overview

Problem

Industrial robots face challenges in maintaining the usability and ease of maintenance of work tools due to umbilical member interference and limited mounting areas, especially when devices like wire feeders are positioned at the rear of the forearm, which restricts adjustment and complicates maintenance.

Innovation Solution

A drive mechanism for the robot arm that allows the umbilical member to extend through a hollow portion or along the outside of the forearm, with a motor and speed reducer positioned between the forearm and upper arm, enabling flexible placement of the work tool device and reducing interference, while maintaining a similar basic configuration to prior art.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the device for the work tool (e.g., wire feeder) is positioned at the rear side of the forearm to avoid interference, then the device does not project widely outward, but the adjustment of the device in the direction parallel to the U-axis is limited and maintenance becomes difficult

Engineering Contradiction:
Improvemounting area of deviceVSAvoidadjustment range and maintenance accessibility
Core Design Contradiction:
Area of stationary objectVSEase of operation

Solution Approach 1:

The motor for the first wrist element is repositioned from the traditional location to the area between the forearm and upper arm, utilizing the third dimension (depth) rather than only the rear surface area. This spatial relocation resolves the contradiction by providing both sufficient mounting area and excellent accessibility for maintenance, as the motor becomes accessible from the side rather than being constrained to the rear surface.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Device complexity

If the umbilical member is drawn from the device positioned at the rear side of the forearm, then the member can be arranged inside the hollow portion of the forearm, but various kinds of umbilical members with large diameters or poor twistability cannot be contained

Engineering Contradiction:
Improverobot arm configurationVSAvoidcompatibility with different umbilical members
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The umbilical member extraction point is relocated from the rear side device to the front end of the wrist element. This extraction allows the umbilical member to be drawn from a different location, enabling members with large diameters or poor twistability to be accommodated without being constrained by the hollow portion of the forearm, thereby increasing versatility while maintaining configuration simplicity.

Inventive Principle:
Principle #2Taking out (Extraction)

3Volume of stationary object

If the motor for rotating the forearm is positioned near the device at the rear side, then the structure is compact, but the adjustment of the device is limited due to interference

Engineering Contradiction:
Improvespace utilizationVSAvoiddevice adjustment freedom
Core Design Contradiction:
Volume of stationary objectVSEase of operation

Solution Approach 1:

The motor functions are segmented and relocated: the motor for the first wrist element is positioned in the area between the forearm and upper arm, separate from the forearm rotation motor. This segmentation allows the device mounted on the forearm to have full adjustment freedom without interference from the motor, while the motor itself has dedicated space for optimal performance.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP1892064B1Drive mechanism for industrial robot arm
Publication Date: 2010.03.03 FANUC LTD
  • EP1892064B1 patent drawingFigure 1a~1b
  • EP1892064B1 patent drawingFigure 2
  • EP1892064B1 patent drawingFigure 3a~3c

AI summary

A drive mechanism for an industrial robot arm, having a simple drive system, in which an extracting part of an umbilical member (54) for a work tool (32) is suitably positioned and a control device (34) for the work tool is positioned on the forearm so as not to project out, while the basic configuration of the robot arm may be similar to the prior art. A motor for a first wrist element (22) is positioned in the area between a forearm and an upper arm such that the rotation axis of the motor is perpendicular to a second axis. Further, the motor is positioned at the point shifted toward the wrist element or a front end of the forearm, in relation to a first axis, along the longitudinal direction of the forearm. Therefore, a wide area for a wire feeder may be obtained above a bottom portion of the forearm.