Sealing Sleeve with Hard Brake Elements for Grinding Machine Wear
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Solution Overview
Problem
Hand-held power tools, such as grinding and polishing machines, experience significant wear on sealing sleeves due to bearing friction, leading to excessive speed of sanding disks and reduced tool efficiency, necessitating frequent replacements.
Innovation Solution
The integration of one or more brake bodies on an elastic sealing collar that wear less than the base material, ensuring optimal contact pressure and maintaining braking surface contact during tool movement, with the sealing sleeve designed to flex and adapt to the tool's movements, and featuring hard sliding surfaces and protrusions for effective braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sealing sleeve is fitted to the disc tool to provide braking, then the disc tool speed is controlled, but the sealing sleeve experiences considerable wear and needs frequent replacement
Solution Approach 1:
The sealing sleeve is segmented into two distinct functional zones: a resilient body portion that provides elastic compliance, and a hard sliding surface portion that provides low-wear braking contact. This segmentation allows each portion to perform its specialized function optimally, resolving the contradiction between maintaining reliable braking and extending service life.
Solution Approach 2:
The sealing sleeve combines two different material properties in one component: a resilient base material (such as elastomer or rubber) that provides elasticity and compliance, and a hard sliding surface material (such as PTFE, polyacetal, or ceramic-coated material) that provides low friction and wear resistance. This composite structure resolves the contradiction by having the resilient material absorb mechanical stress while the hard material resists wear during braking.
2Adaptability or versatility
If the sealing sleeve is made elastic to accommodate tool movements, then braking surfaces remain in contact, but the sealing sleeve material wears faster
Solution Approach 1:
Different portions of the sealing sleeve have different material properties tailored to their specific functions: the body portion is made resilient to accommodate tool movements and maintain contact pressure, while the sliding surface portion is made of hard, low-wear material to resist abrasion during braking. This local differentiation of material quality resolves the contradiction between adaptability and wear resistance.
Solution Approach 2:
The hard sliding surface is applied as a coating or overlay on the resilient body, creating a surface layer that copies the beneficial properties of hard, low-wear materials while the underlying resilient material provides the necessary compliance. This layered approach allows the resilient material to perform its compliance function without directly experiencing the wear that would otherwise degrade it.
3Reliability
If brake elements are arranged on the sealing sleeve to reduce wear, then braking efficiency improves, but the device complexity increases
Solution Approach 1:
The braking function and sealing function are merged into a single integrated component - the sealing sleeve itself. The hard sliding surface is incorporated directly into the sealing sleeve structure, eliminating the need for separate brake elements and reducing overall device complexity while maintaining improved braking efficiency and reduced wear.
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 significantly reduces sealing sleeve wear, maintains consistent braking performance, and extends tool life by ensuring the braking surfaces remain in contact, preventing excessive disk speed and improving operational efficiency.
Implementation Method 1
The sealing sleeve body provides the elastic component, ensuring optimal pressure on the sliding surface(s) of the at least one brake element. A further advantage arises from the fact that the sealing sleeve yields elastically and thus accommodates the movements of the disc tool, including flexing and wobbling movements
Implementation Method 2
The brake elements are subject to significantly less wear than the base material of the sealing sleeve body. The braking surface arrangements rub against each other and brake the disc tool when the disc tool rotates around a rotational axis relative to the rotationally fixed braking surface arrangement during operation of the hand-held machine tool
Data Source
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AI summary
The invention relates to a hand-held power tool (10), in particular a grinding and/or polishing machine, with a drive motor (12), in particular electric or pneumatic, for rotary driving a tool holder (18) on which a disc tool (40), in particular a grinding or polishing disc, can be attached by means of a machine holder (42), wherein a machine braking surface arrangement (28) for braking the disc tool (40) is arranged non-rotatably on a housing (11) of the hand-held power tool (10) next to the tool holder (18), against which a tool braking surface arrangement (48) arranged on a disc body (41) of the disc tool (40) rubs during operation of the hand-held power tool (10), wherein a gap (33) between the disc tool (40) and a housing (11) of the hand-held power tool (10) is surrounded by a sealing sleeve (50) comprising an elastic sealing sleeve body (51).on which at least one braking surface of the machine braking surface arrangement (28) or the tool braking surface arrangement (48) is provided. It is provided that at least one braking element (66) is arranged on the sealing sleeve body (51), which has a sliding surface (67) that forms part of the machine braking surface arrangement (28) or the tool braking surface arrangement (48) and is harder than the base material of the sealing sleeve body (51).