Contactless Sealing Geometry for Mobile Tool Drive Units
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Solution Overview
Problem
Mobile power tools experience significant friction and thermal stress in their drive units due to conventional sealing geometries, leading to reduced service life, increased maintenance costs, and safety hazards.
Innovation Solution
A contactless sealing geometry with a seal that maintains separation between the drive unit's interior and exterior, utilizing vortex flows and low-pressure forces to minimize friction and thermal stress, and incorporating materials resistant to water and high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional contact-based seal is used to seal off the lubricant interior from the exterior, then sealing effectiveness is improved, but friction and thermal stress increase significantly
Solution Approach 1:
The patent replaces the conventional mechanical contact-based sealing system with a magnetic field-based sealing system. The magnetic seal uses magnetic attraction forces to retain lubricant without physical contact between the rotor and stator sealing surfaces, thereby eliminating friction and thermal stress while maintaining sealing effectiveness.
Solution Approach 2:
The patent changes the fundamental operating parameter of the seal from contact-based mechanical force to contactless magnetic field force. This parameter change allows the seal to function without friction, solving the contradiction between sealing effectiveness and friction/thermal stress generation.
2Duration of action of stationary object
If a contactless seal is used to eliminate friction, then service life is improved, but sealing effectiveness under high pressure may deteriorate
Solution Approach 1:
The patent utilizes the adjustable strength of magnetic fields to maintain sealing effectiveness under varying pressure conditions while keeping the sealing surfaces contactless. The magnetic field parameters can be optimized to provide sufficient retaining force against high pressure without requiring physical contact.
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 solution extends the service life of the sealing geometry, reduces maintenance costs, and enhances work output while maintaining operational safety and flexibility, particularly in high-performance and cordless tools.
Implementation Method 1
The magnetic seal has a stationary part that is fixed to the housing and a rotating part that is fixed to the rotor. The magnetic seal is designed such that, during operation of the drive unit, no friction occurs between the rotating part and the stationary part. The magnetic seal retains the lubricant in the interior of the drive unit without the lubricant coming into contact with the rotating part and the stationary part.
Data Source
AI summary
A sealing geometry for a mobile power tool is provided wherein the mobile power tool has a drive unit, wherein the sealing geometry is designed to seal off an interior (IB), containing a lubricant, of the drive unit from an exterior (AB) outside the drive unit. The sealing geometry has a seal that is contactless at least during operation of the drive unit.