Robot Arm Joint Assembly via Radial Pin Insertion

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Solution Overview

Problem

Current robot arm assembly methods are complex and costly, requiring step-by-step joint assembly and often relying on pressing or gluing, which can be problematic, especially when using inexpensive deep groove ball bearings, making it difficult to pre-assemble complete structural mechanics and linear bases with drives and electronics.

Innovation Solution

A robot arm design featuring pre-assembled link and joint assemblies with a unique joint structure where the first link has a bearing pin and a second link with a circumferentially closed and open recess, allowing for radial insertion and pivoting, secured by a bearing support ring, enabling cost-effective and simple assembly by pivoting rather than axial alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional step-by-step joint assembly methods are used, then assembly precision can be maintained, but assembly complexity and cost increase significantly

Engineering Contradiction:
Improveassembly simplicityVSAvoidassembly process complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The robot arm is divided into modular link assemblies that can be pre-assembled separately and then connected through simple joining operations. Each link assembly contains pre-mounted bearings and structural elements, allowing parallel production and reducing final assembly complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Bearings and structural components are pre-assembled onto links before final joint assembly. The bearing pins are pre-positioned on links, and bearing flanges are pre-configured with recesses, enabling rapid final assembly without complex alignment procedures.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If pressing or gluing methods are used for joint assembly, then structural stability can be achieved, but reliability decreases when using inexpensive deep groove ball bearings

Engineering Contradiction:
Improvejoint assembly reliabilityVSAvoidassembly method simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Cylindrical bearing pins with circular cross-sections are used instead of pressed-fit or glued connections. The circular geometry of the bearing pins allows for radial insertion through circumferentially open recesses and rotation into final position, providing reliable mechanical connection without pressing or gluing.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The bearing flange recesses are designed with specific geometric parameters including circumferential openness and radial depth, allowing bearing pins to be inserted radially and rotated into place. This geometric configuration enables reliable assembly of inexpensive deep groove ball bearings without requiring pressing or adhesive bonding.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If pre-assembly of complete structural mechanics is attempted, then productivity increases, but manufacturing precision may be compromised

Engineering Contradiction:
Improveassembly efficiencyVSAvoidjoint alignment precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The robot arm structure is segmented into link assemblies with standardized bearing flanges and bearing pins. Each segment can be manufactured and pre-assembled independently with controlled tolerances, then joined through simple radial insertion and pivoting operations that maintain overall alignment precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Standardized bearing flanges with circumferentially open recesses and corresponding bearing pins are used across multiple joints, allowing pre-assembled link modules to be universally interchangeable. This standardization enables efficient pre-assembly while maintaining precision through consistent geometric interfaces.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4244025B1Robot arm and method for assembling a robot arm
Publication Date: 2024.10.09 KUKA DEUT GMBH
  • EP4244025B1 patent drawingFigure 1
  • EP4244025B1 patent drawingFigure 2
  • EP4244025B1 patent drawingFigure 3

AI summary

The invention relates to a robot arm (1) having multiple links (2) and multiple joints (3) connecting the links (2) such that they are adjustable relative to one another. At least one first link (2.1) of these links (2) has a first bearing pin (4.1) and a second bearing pin (4.2) located opposite the first bearing pin (4.1), and a second link (2.2), which is pin-connected to the first link (2.1) by one of the joints (3), has a first bearing flange (5.1) on which the first bearing pin (4.1) of the first link (2.1) is rotatably mounted, and a second bearing flange (5.2) on which the second bearing pin (4.2) of the first link (2.1) is rotatably mounted. The first bearing flange (5.1) of the second link (2.2) has a recess (6a) which is circumferentially closed and in which the first bearing pin (4.1) of the first link (2.1) is received, and the second bearing flange (5.2) of the second link (2.2) has a recess (6b) which is circumferentially open and in which the second bearing pin (4.2) of the first link (2.1) is received. An opening (7) in the circumferentially open recess (6b) has an opening width (W) that is greater than the width of the second bearing pin (4.2) of the first link (2.1), and the second bearing flange (5.2) has a securing means (8) which is secured to the second bearing pin (4.2) of the first link (2.1) on the circumferentially open recess (6b) of the second bearing flange (5.2). The invention also relates to a method for assembling such a robot arm (1).