Robotic Lawn Mower Wheel Brush Shielding Against Grass Adhesion

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Solution Overview

Problem

Robotic lawn mowers face challenges in efficiently removing cut grass and debris from their drive wheels, which often adhere due to the design of existing cleaning devices.

Innovation Solution

The robotic lawn mower incorporates wheel brush devices with holding rods and brush bristles positioned between the drive wheels and swivelable wheels, equipped with grass shields to prevent cut grass from adhering to the bristles, and motor-driven rotation for effective cleaning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If wheel brush devices are positioned between drive wheels and swivelable wheels for cleaning, then cleaning effectiveness is improved, but cut grass and debris adhere to the brush bristles reducing performance

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidgrass adhesion to bristles
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

A grass shield is introduced as an intermediary component between the cutting disc and the wheel brush device. This shield prevents cut grass from directly contacting the brush bristles, thereby eliminating the adhesion problem while preserving the cleaning function of the brushes on the drive wheels

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If brush bristles are arranged to contact the drive wheel surface for cleaning, then debris removal is enhanced, but the brush devices become complex requiring holding rods and mounting mechanisms

Engineering Contradiction:
Improvedebris removal efficiencyVSAvoidbrush device structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The wheel brush devices are designed to rotate dynamically, with the brush bristles contacting the drive wheel surface during rotation. This dynamic arrangement allows effective cleaning without requiring complex fixed mounting structures, as the brushes naturally conform to the wheel surface during operation

Inventive Principle:
Principle #15Dynamics

3Productivity

If wheel brush devices are equipped with motor-driven rotation for active cleaning, then cleaning performance is improved, but energy consumption and device complexity increase

Engineering Contradiction:
Improvewheel cleaning efficiencyVSAvoidmotor energy consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The wheel brush devices are designed to be self-driven, where the rotation of the drive wheels themselves powers the brush devices. This eliminates the need for separate motors, reducing energy consumption while maintaining effective cleaning performance through the natural contact and rotation mechanism

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4662999A1A robotic lawn mower with wheel brush device
Publication Date: 2025.12.17 HUSQVARNA AB
  • EP4662999A1 patent drawingFigure 1~2
  • EP4662999A1 patent drawingFigure 3~4
  • EP4662999A1 patent drawingFigure 5

AI summary

The present disclosure relates to a robotic lawn mower (100) comprising a body (140), at least one pair of drive wheels (131A, 131B), at least one swivelable wheel (130A, 130B), at least one rotatable grass cutting disc (160), having a disc rotation axle (165) that is adapted to rotate about a disc rotation axis (164), and at least one wheel brush device (150A, 150B) for each drive wheel (131A, 131B). Each wheel brush device (150A, 150B) is arranged mainly between the respective drive wheel (131A, 131B) and at least one swivelable wheel (130A, 130B) and comprises holding means (151A, 151B) holding a plurality of brush bristles (152A, 152B) that are comprised in the respective wheel brush device (150A, 150B) and are adapted to bear on the respective drive wheel (131A, 131B). The robotic lawn mower (100) comprises a grass shield (153A, 153B) for each wheel brush device (150A, 150B), each grass shield (153A, 153B) being arranged between the cutting disc (160) and the respective brush bristles (152A, 152B) to prevent cut grass that is ejected from the cutting disc (160) from adhering to the respective brush bristles (152A, 152B).