Angle Grinder Bearing Housing for Split Airflow Cooling

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Solution Overview

Problem

Existing hand-held power tools face inefficiencies in airflow management and cooling, leading to suboptimal performance and potential damage from overheating.

Innovation Solution

The design incorporates an air inlet opening that directs airflow around the drive unit and bearing unit, with a split airflow system ensuring both internal and external exposure, and an air guide plate to enhance cooling efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the drive unit is fully enclosed in the machine housing for protection, then reliability is improved, but cooling effectiveness deteriorates due to restricted airflow

Engineering Contradiction:
Improveprotection of drive unitVSAvoidcooling effectiveness
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The machine housing is segmented into multiple parts (first housing part, second housing part, bearing housing) that can be selectively assembled to create different airflow configurations. The bearing housing specifically segments the drive unit enclosure to allow airflow through defined paths while maintaining protection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bearing housing acts as an intermediary component between the drive unit and the machine housing. It provides a structured interface that enables controlled airflow around the drive unit while maintaining the protective enclosure, thus mediating between cooling requirements and protection needs.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the drive unit is mounted with full support structures for stability, then reliability is improved, but airflow volume deteriorates due to blocked passages

Engineering Contradiction:
Improvestability of drive unitVSAvoidairflow volume
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The support structure is segmented into discrete bearing elements (first bearing element, second bearing element) positioned at specific locations. This segmentation allows airflow to pass through the spaces between bearing elements while still providing adequate support for the drive unit.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The drive unit is supported in the radial direction by bearing elements rather than axial support structures. This dimensional change in support orientation allows airflow to move axially through the drive unit region without being blocked by support structures.

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

3Temperature

If the air inlet opening is positioned to maximize airflow volume, then cooling effectiveness is improved, but airflow distribution uniformity deteriorates

Engineering Contradiction:
Improvecooling effectivenessVSAvoidairflow distribution
Core Design Contradiction:
TemperatureVSQuantity of substance

Solution Approach 1:

Different regions of the bearing housing are designed with different airflow characteristics. The air inlet opening is positioned to create a circumferential airflow pattern that distributes air uniformly around the drive unit, while the air outlet opening is positioned to capture this distributed airflow. This local differentiation of airflow properties achieves both high volume and uniform distribution.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The bearing housing and air inlet/outlet openings are designed with curved, circumferential geometries rather than linear arrangements. This curvature enables the airflow to follow a circular path around the drive unit, ensuring uniform distribution of cooling air across all circumferential regions while maintaining high airflow volume.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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

This configuration significantly increases airflow volume and cooling effectiveness, preventing overheating and improving the tool's operational reliability and longevity.

Implementation Method 1

an air inlet opening (61) designed to direct an airflow (L1) in such a way that an airflow flows around a circumferential area (57) of the drive unit (13) and/or the bearing unit (25), particularly in the axial direction

Methodology Applied
Scientific EffectAirflow: Convection

Implementation Method 2

the circumference of the drive shaft and the machine housing form an airflow chamber (59) designed to guide an airflow (L1) along the drive unit (13). This allows the amount of cooling air flowing through the power tool to be increased

Methodology Applied
Scientific EffectConvection cooling: Convection

Implementation Method 3

an air guide plate (63), in particular with an air guide recess (65), designed to direct the airflow (L1) axially through the air guide plate (63)

Methodology Applied
Scientific EffectGuided airflow: Convection

Data Source

PatentEP4484055B1Hand-held power tool
Publication Date: 2025.12.24 ROBERT BOSCH GMBH
  • EP4484055B1 patent drawingFigure 1
  • EP4484055B1 patent drawingFigure 2
  • EP4484055B1 patent drawingFigure 3

AI summary

The invention relates to a hand-held power tool, in particular an angle grinder, comprising a drive unit (13), a machine housing (15), in particular comprising a first housing part (17) designed as a gearbox housing and a second housing part (19) surrounding the drive unit (13), and a bearing unit (25), in particular a bearing housing (27), for supporting the drive unit (13). It is proposed that the bearing unit (25) projects into the first housing part (17).