Low-Height Differential Drive Structure for AGV Rotation

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Solution Overview

Problem

The existing differential drive devices for automated guided vehicles (AGVs) are limited by their high height due to the use of slewing bearings, which restricts their application in spaces with height constraints.

Innovation Solution

A differential drive device design that replaces the slewing bearing with a top plate and outer cover configuration, incorporating rolling members to facilitate rotation and reduce friction, allowing the differential drive unit to rotate relative to the top plate and outer cover, thereby reducing the overall height and improving stability and motion accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a sleving bearing is used to realize rotation connection between the differential drive device and the vehicle body, then the rotation function is achieved, but the total height of the differential drive device becomes relatively large

Engineering Contradiction:
Improverotation functionVSAvoidtotal height
Core Design Contradiction:
Ease of operationVSLength of stationary object

Solution Approach 1:

The patent changes the spatial arrangement from a vertical configuration (sleving bearing occupying vertical height) to a horizontal configuration (rolling members arranged radially around the central axis). The rolling members are positioned at different angular positions around the central axis, converting the vertical height problem into a horizontal radius problem, thereby reducing the total height of the differential drive device while maintaining the rotation function.

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

Solution Approach 2:

The patent uses multiple rolling members (at least two) distributed around the central axis to replicate the rotation support function that would otherwise require a single sleving bearing. Each rolling member independently supports the rotating platform, and their combined effect achieves the same rotation function as a sleving bearing but with reduced vertical height requirement.

Inventive Principle:
Principle #26Copying

2Length of stationary object

If rolling members are used to replace sleving bearing, then the height is reduced, but the friction and wear increase

Engineering Contradiction:
ImproveheightVSAvoidfriction and wear
Core Design Contradiction:
Length of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the sliding friction mechanism of a sleving bearing with a rolling friction mechanism using rolling members. The rolling members rotate on their axes while supporting the rotating platform, converting sliding friction into rolling friction. This substitution significantly reduces friction and wear compared to traditional sleving bearings, addressing the harmful effects while maintaining the height reduction benefit.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If the differential drive unit rotates relative to the top plate and outer cover, then motion accuracy is improved, but the structural complexity increases

Engineering Contradiction:
Improvemotion accuracyVSAvoidstructural complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent segments the rotation support function into multiple independent rolling members rather than using a single integrated sleving bearing. Each rolling member is a simple, standardized component that can be independently manufactured and assembled. This segmentation approach improves motion accuracy through better load distribution and reduced friction, while the modular nature of individual rolling members actually simplifies manufacturing and assembly compared to a complex sleving bearing.

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution effectively reduces the total height of the differential drive device, enhances stability, and improves motion accuracy by reducing friction and wear, while maintaining the functionality of differential rotation and forward/backward walking.

Implementation Method 1

a first rolling member is provided on a side of the differential drive unit. The first rolling member is in rolling connection with the lower side of the top plate

Methodology Applied
Scientific EffectRolling contact: Roller

Data Source

PatentEP3929064B1Differential drive device and AGV
Publication Date: 2025.01.01 HANGZHOU HIKROBOT TECH CO LTD
  • EP3929064B1 patent drawingFigure 1~2
  • EP3929064B1 patent drawingFigure 3~4
  • EP3929064B1 patent drawingFigure 5~6

AI summary

The present application discloses a differential drive device applied to an AGV, relating to the field of wheeled drivers, and being able to effectively reduce the total height of the differential drive device. The differential drive device includes a differential drive unit (2), a top plate (1) and an outer cover (3). The top plate (1) is installed on a top end of the outer cover (3). The differential drive unit (2) is located in the outer cover (3) at a lower side of the top plate (1). The top plate (1) is supported on the differential drive unit (2). An inner side wall of the outer cover (3) is circular-shaped. The present application applies to apparatuses with transportation functions.