Fan Element Sealing Integration for Hand Tool Drive Units

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Solution Overview

Problem

Existing hand-held power tool devices face challenges in achieving a compact and cost-effective sealing solution for their transmission units, particularly in the axial direction, while maintaining efficient heat dissipation and secure component integration.

Innovation Solution

The integration of a sealing ring made of felt, directly and firmly connected to the fan element, which is pressed onto the transmission element, providing a secure and space-saving seal without significantly increasing the device's length, and utilizing a planetary gear for speed adaptation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate sealing component is used for the transmission unit, then sealing reliability is improved, but device complexity and assembly cost increase

Engineering Contradiction:
Improvesealing reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sealing element is integrated directly into the fan element by forming it as a separate component that is pressed onto the transmission element along with the fan element. This merging of sealing function into the cooling unit structure achieves reliable sealing while reducing device complexity and eliminating separate sealing components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The fan element is designed to serve multiple functions: it provides cooling airflow through its fan blades, transmits rotational movement from the transmission element, and incorporates the sealing element to prevent lubricant leakage. This multi-functionality reduces the overall number of components while maintaining sealing reliability.

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

2Reliability

If a separate sealing component is used for the transmission unit, then sealing reliability is improved, but manufacturing and assembly costs increase

Engineering Contradiction:
Improvesealing reliabilityVSAvoidmanufacturing and assembly costs
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The sealing element is integrated directly into the fan element by forming it as a separate component that is pressed onto the transmission element along with the fan element. This merging of sealing function into the cooling unit structure achieves reliable sealing while reducing device complexity and eliminating separate sealing components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The sealing element is pre-integrated into the fan element during manufacturing, so that when the fan element is assembled onto the transmission element, the sealing function is already in place. This preliminary integration reduces assembly steps and costs while ensuring proper sealing installation.

Inventive Principle:
Principle #10Preliminary action

3Length of moving object

If the sealing element is integrated into the fan element, then device compactness is improved, but the receiving area space is reduced

Engineering Contradiction:
Improvedevice length in axial directionVSAvoidreceiving area space
Core Design Contradiction:
Length of moving objectVSArea of stationary object

Solution Approach 1:

The sealing element is positioned in the axial direction between the fan element and the transmission housing, utilizing the axial dimension rather than consuming additional radial or circumferential space. This dimensional arrangement maintains device compactness while providing adequate space for the sealing element's function.

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

Solution Approach 2:

The sealing element is nested within the structure formed by the fan element and transmission housing, fitting into the available axial space without requiring additional external volume. This nesting approach achieves compact integration while maintaining sufficient receiving area for sealing effectiveness.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 allows for a compact, cost-effective, and reliable sealing solution that prevents fluid leakage while maintaining efficient heat dissipation and multifunctionality, reducing manufacturing and assembly costs.

Implementation Method 1

a fluid flow can be generated for heat dissipation within the hand-held power tool device, in particular the drive unit

Methodology Applied
Scientific EffectHeat dissipation: Convection

Implementation Method 2

at least one sealing element which forms a seal of the transmission unit

Methodology Applied
Scientific EffectSealing: Physical Containment

Data Source

PatentEP2809484B1Hand tool machine device
Publication Date: 2018.11.21 ROBERT BOSCH GMBH
  • EP2809484B1 patent drawingFigure 1
  • EP2809484B1 patent drawingFigure 2

AI summary

The invention relates to a hand tool machine device with a drive unit (10) comprising at least one drive shaft (12), with a gear unit (14) comprising at least one gear element (16), with a cooling unit (18) comprising at least one fan element (20) and with at least one sealing element (22) that is provided in particular for sealing the gear unit (14) in at least one axial direction (24). The invention proposes that the at least one fan element (20) has at least one receiving area (26) provided at least substantially for receiving the at least one sealing element (22).