Movable Shaft Sealing Assembly for Long-Life Handheld Waterproofing
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Solution Overview
Problem
Handheld devices, such as electric toothbrushes, face challenges in achieving long-lasting waterproofing for their center shafts, especially when these devices require larger rotational strokes and higher frequency reversals, leading to premature failure of sealing members and increased maintenance needs.
Innovation Solution
A shaft sealing assembly is introduced, comprising a center shaft and a movable sealing assembly with a fixation seat and a movable sealing member made of flexible material. The sealing member is designed to form seals at both the front and rear walls of the sealing slot, rotating with the center shaft to prevent wear and enhance sealing efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the center shaft rotates at a larger rotational stroke and switches between forward and reverse rotation at a higher frequency, then the tooth-brushing effect is enhanced, but the waterproof sealing member wears out faster and fails prematurely
Solution Approach 1:
The patent inverts the traditional sealing arrangement by making the sealing member movable rather than stationary. The movable sealing member rotates together with the center shaft, while the sealing slot is formed on the stationary fixation seat. This inversion transfers the sealing function from the rotating center shaft to the stationary fixation seat, eliminating wear at the sealing interface and enabling high-frequency rotational movements without compromising waterproof performance
Solution Approach 2:
The patent introduces a movable sealing member that dynamically adapts to the rotational movements of the center shaft. The sealing member is designed to move radially and rotate with the center shaft, maintaining continuous contact with the sealing slot walls. This dynamic configuration allows the sealing system to accommodate large rotational strokes and high-frequency reversals while maintaining effective waterproof sealing
2Reliability
If a traditional waterproof sealing member is used on the center shaft, then the device achieves waterproofing, but the sealing member wears out due to constant movement
Solution Approach 1:
The patent inverts the traditional sealing arrangement by making the sealing member movable rather than stationary. The movable sealing member rotates together with the center shaft, while the sealing slot is formed on the stationary fixation seat. This inversion transfers the sealing function from the rotating center shaft to the stationary fixation seat, eliminating wear at the sealing interface and enabling high-frequency rotational movements without compromising waterproof performance
Solution Approach 2:
The movable sealing member acts as an intermediary between the rotating center shaft and the stationary fixation seat. It transfers the rotational motion from the center shaft to the sealing interface, allowing the sealing slot to remain stationary while still achieving effective sealing. This intermediary mechanism protects the sealing function from wear by decoupling the rotational movement from the sealing contact surfaces
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 proposed solution extends the waterproof service life of the handheld device's shaft sealing assembly, reduces after-market maintenance, and improves the sealing effect by transferring the sealing interface to the movable sealing member, which rotates without wear and increases the sealing area.
Implementation Method 1
The movable sealing member is made of flexible material, the movable sealing member is received in the sleeving hole and extends into the sealing slot
Implementation Method 2
an oily sealing material filled in the sealing compartment, the oily sealing material forms an oil sealing interface between the movable sealing member and the front wall surface and an oil sealing interface between the movable sealing member and the rear wall surface
Data Source
AI summary
A shaft sealing assembly of a handheld device includes: a center shaft; and a movable sealing assembly, including a fixation seat and a movable sealing member. The fixation seat defines a sleeving hole, an inner circumferential surface of the sleeving hole defines an annular sealing slot, the sealing slot has a front wall surface and a rear wall surface opposite to the front wall surface in an axial direction. The movable sealing member is made of flexible material, the movable sealing member is received in the sleeving hole and extends into the sealing slot, the movable sealing member defines a fixation shaft hole which is sealed to and fixedly sleeves the center shaft, the movable sealing member is sealed to and rotatably mated to the front wall surface and the rear wall surface.