Power Tool Partition Assembly With Labyrinth Sealing
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Solution Overview
Problem
Existing power tools face challenges in inhibiting dust and grease migration between the transmission and motor assemblies, leading to contamination and potential mechanical issues.
Innovation Solution
A partition assembly is introduced between the transmission and motor assemblies, featuring labyrinth paths and seals to trap and inhibit grease and dust migration, while facilitating heat transfer and alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a partition assembly with labyrinth paths is introduced between transmission and motor assemblies, then grease and dust migration is inhibited, but device complexity increases
Solution Approach 1:
A partition assembly is introduced as an intermediary component between the transmission assembly and motor assembly. This partition includes labyrinth paths that act as a barrier to grease and dust migration while allowing the motor output shaft to pass through and transmit power. The labyrinth structure creates a complex path that contaminants must traverse, effectively blocking their movement between assemblies.
Solution Approach 2:
The partition assembly is segmented into multiple components including a first plate with a first labyrinth path, a second plate with a second labyrinth path, and a seal. This segmentation allows each component to perform a specific function in the contamination barrier system while maintaining overall structural integrity and allowing for easier manufacturing and assembly.
2Reliability
If a partition assembly is introduced between transmission and motor assemblies, then contamination is reduced, but manufacturing complexity increases
Solution Approach 1:
The partition assembly is divided into multiple manufacturable components: a first plate, a second plate, and a seal. Each component can be manufactured separately using standard manufacturing processes, then assembled together. The labyrinth paths are formed by the relative positioning of these segmented components rather than requiring complex monolithic manufacturing.
Solution Approach 2:
The partition assembly serves as an intermediary structure that can be manufactured and assembled independently of the motor and transmission assemblies. This modular approach allows each sub-assembly to be manufactured separately with standard tolerances, then integrated into the final product, reducing overall manufacturing complexity.
3Reliability
If labyrinth paths are created in the partition, then grease and dust migration is inhibited, but heat transfer capability is reduced
Solution Approach 1:
The partition assembly with labyrinth paths acts as a thermal intermediary between the transmission assembly (which generates heat) and the motor assembly. While the labyrinth paths block grease and dust, the metal plates of the partition still conduct heat across the barrier, allowing thermal energy to pass while mechanical contaminants are blocked by the complex path geometry.
Solution Approach 2:
The partition assembly provides different functional qualities in different regions: the labyrinth paths provide contamination barrier functionality, while the overall plate structure provides thermal conduction pathways. This local differentiation of function allows simultaneous achievement of contamination prevention and heat transfer.
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 partition assembly effectively reduces grease and dust contamination, enhances mechanical integrity, and improves heat dissipation, thereby improving the reliability and performance of the power tool.
Implementation Method 1
The rear cover and the front end portion together define at least a first labyrinth path and a second labyrinth path therebetween configured to inhibit grease or dust migration between the transmission housing and the motor assembly
Implementation Method 2
A seal may be disposed between a front face of the rear cover and the rear end portion of the transmission housing to further inhibit grease or dust migration between the transmission housing and the motor assembly
Implementation Method 3
The front end portion of the motor may include a fan coupled to the output shaft for cooling the motor
Implementation Method 4
A gear of a first stage of the transmission assembly may abut the rear cover to facilitate heat transfer from the transmission assembly
Data Source
AI summary
A power tool includes a tool housing and a motor assembly received in the tool housing. The motor assembly has a rear end portion, a front end portion, and a motor output shaft. A transmission housing is coupled to the motor housing with a transmission received in the transmission housing, to which the motor output shaft is drivingly coupled. A partition assembly includes a rear cover covering a rear end portion of the transmission housing that faces the front end portion of the motor and a seal. The rear cover of the transmission housing, the front end portion of the motor, and the seal together define at least a first labyrinth path and a second labyrinth path therebetween configured to inhibit grease or dust migration between the transmission housing and the motor assembly.