Power Tool Spacer Element With Labyrinth Seal for Gearbox Leakage
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Solution Overview
Problem
Existing hand-held power tools face challenges in maintaining a compact design while preventing lubricant leakage from the gearbox to the drive motor, which can cause damage and require separate sealing elements.
Innovation Solution
A disk-shaped spacer element with a tubular bearing section is used between the gearbox and drive motor, forming a labyrinth seal to prevent lubricant leakage, allowing for a compact connection and reducing the overall length of the tool by collecting lubricant in a circular ring segment receptacle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate sealing element is used to prevent lubricant leakage, then reliability is improved, but device complexity increases and length increases
Solution Approach 1:
The patent combines the sealing function with the spacer element by forming a labyrinth seal directly on its peripheral surface. This integration eliminates the need for separate sealing elements while maintaining reliable lubricant containment, thus improving reliability without increasing device complexity
Solution Approach 2:
The spacer element is designed to perform multiple functions simultaneously: it provides spacing between components, supports the motor shaft through bearing sections, and prevents lubricant leakage through the integrated labyrinth seal. This multi-functionality reduces the overall number of components needed in the system
2Reliability
If a separate sealing element is used to prevent lubricant leakage, then reliability is improved, but the length of the tool increases
Solution Approach 1:
By integrating the sealing function into the spacer element's peripheral surface, the patent eliminates the need for additional sealing components that would extend the tool's length. The combined structure achieves reliable lubricant containment within the existing spatial envelope
Solution Approach 2:
The labyrinth seal is formed as an integral part of the spacer element structure, with sealing labyrinths nested within the spacer's peripheral surface. This nesting approach allows the sealing function to be embedded within the existing component geometry without adding external length
3Device complexity
If the spacer element forms an integrated labyrinth seal, then device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
While integrating functions typically increases manufacturing complexity, the labyrinth seal is formed using standard machining operations on the spacer element's peripheral surface. The seal geometry is designed to achieve effective sealing with conventional manufacturing tolerances, balancing integration benefits with manufacturability
4Length of moving object
If the bearing section engages in the gear housing, then compactness is improved, but ease of assembly may worsen
Solution Approach 1:
The spacer element is designed with segmented bearing sections that can be independently positioned and engaged with the gear housing. This segmentation allows for simplified assembly procedures while maintaining the compact engagement configuration, as components can be assembled in a standardized sequence
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 solution enables a compact and reliable hand-held power tool design by eliminating the need for a separate sealing element, preventing lubricant escape, and reducing the tool's length, thus enhancing its structural integrity and operational efficiency.
Implementation Method 1
The spacer element forms a seal, in particular a labyrinth seal
Implementation Method 2
A tubular bearing section for mounting on the motor shaft is formed on the disc-shaped base body
Data Source
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AI summary
In a hand-held power tool with a tool holder (150) and a housing in which a drive motor (114) with a motor shaft (116) and a gearbox (118) are arranged, wherein the gearbox (118) is arranged in a gearbox housing (119), and wherein a spacer element (250) is arranged between the gearbox (118) and the drive motor (114), which has a disk-shaped base body (252) on which a tubular bearing section (251) for bearing on the motor shaft (116) is formed, the spacer element (250) forms a seal, in particular a labyrinth seal.