Spacer Element Labyrinth Seal for Compact Hand-Held Machine Tools
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Solution Overview
Problem
Existing hand-held machine tools face challenges in achieving a compact design while effectively preventing lubricant leakage from the transmission to the drive motor, which can cause damage.
Innovation Solution
A spacer element with a disc-shaped base body and tubular mounting portion is used to form a labyrinth seal between the transmission and drive motor, collecting lubricant and preventing its leakage, thereby allowing a compact and damage-free arrangement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate sealing element is used to prevent lubricant leakage, then the reliability of preventing lubricant leakage is improved, but the device complexity increases and the overall length increases
Solution Approach 1:
The sealing function is merged into the spacer element itself. The spacer element combines both the spacing function and the sealing function in a single component, eliminating the need for separate sealing elements. The labyrinth seal structure is integrated directly into the spacer element's geometry, creating a compact design that prevents lubricant leakage without adding additional components.
Solution Approach 2:
The spacer element is designed to perform multiple functions simultaneously: it provides mechanical spacing between components, acts as a labyrinth seal to prevent lubricant leakage, and serves as a structural support element. This multi-functionality reduces the overall number of components needed in the drive unit.
2Reliability
If a separate sealing element is used to prevent lubricant leakage, then the reliability of preventing lubricant leakage is improved, but the overall length of the hand-held machine tool increases
Solution Approach 1:
The sealing function is merged into the spacer element itself. The spacer element combines both the spacing function and the sealing function in a single component, eliminating the need for separate sealing elements. The labyrinth seal structure is integrated directly into the spacer element's geometry, creating a compact design that prevents lubricant leakage without adding additional components.
3Device complexity
If the spacer element forms a labyrinth seal, then the device complexity is reduced by omitting separate sealing elements, but the manufacturing precision requirements increase
Solution Approach 1:
The labyrinth seal structure is designed with specific local geometric features on the spacer element that create effective sealing paths. The seal effectiveness is achieved through carefully designed local geometries (labyrinth passages) rather than requiring high precision across the entire component. This allows standard manufacturing tolerances to be used while still achieving reliable sealing.
4Length of moving object
If the mounting portion engages the motor shaft in the transmission housing, then a compact connection is achieved, but the ease of assembly may be reduced
Solution Approach 1:
The spacer element is designed as a separate modular component with a mounting portion that can be independently manufactured and then assembled to the motor shaft. This segmentation allows for simplified manufacturing of individual components and easier assembly, as the spacer element can be pre-assembled with the motor shaft before installation into the transmission housing.
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 spacer element enables a compact design by preventing lubricant leakage, ensuring the drive motor's integrity and reducing the overall length of the hand-held machine tool.
Implementation Method 1
The spacer element forms a seal, in particular a labyrinth seal
Data Source
AI summary
The disclosure relates to a hand-held machine tool comprising a tool receptacle and a housing, in which a drive motor having a motor shaft and a transmission are arranged. The transmission is arranged in a transmission housing, and wherein a spacer element is arranged between the transmission and the drive motor, which spacer element comprises a disc-shaped base body on which a tubular mounting portion is formed for mounting on the motor shaft, said spacer element forming a seal, in particular a labyrinth seal.