Magnetic Fluid Shaft Seal Assembly for Runout-Tolerant Mounting
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Solution Overview
Problem
Magnetic fluid sealing devices are prone to damage due to insufficient precision in mounting and machining, preventing their application in non-precision products like fans, valves, and pumps, and reducing their service life.
Innovation Solution
A magnetic fluid sealed shaft assembly with a resilient member that allows for runout and angle adjustment of the magnetic fluid sealing device, coupled with gas blockage cavities to ensure sealing and protection, mitigating the effects of imperfect perpendicularity and coaxiality between the rotating shaft and fixed structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic fluid sealing device is rigidly fixed to the fixed structure, then the sealing device is stable and precisely positioned, but the device cannot accommodate runout and mounting precision errors, leading to damage and reduced service life
Solution Approach 1:
The magnetic fluid sealing device is transformed from a rigid fixed structure to a dynamic flexible connection through the resilient member. The resilient member allows the sealing device to dynamically adjust its position and absorb runout errors, converting a static precision-critical connection into a dynamic error-tolerant system.
Solution Approach 2:
The mechanical connection parameters are changed from rigid fixed positioning to flexible elastic positioning. The resilient member introduces elastic deformation capability, allowing the system to accommodate position and angle deviations without compromising the sealing function or causing damage.
2Adaptability or versatility
If the magnetic fluid sealing device is made to accommodate runout and angle adjustment, then the device can be used in low-precision products, but the connection structure becomes more complex
Solution Approach 1:
The resilient member acts as an intermediary element between the magnetic fluid sealing device and the fixed structure. It mediates the connection by providing flexible coupling that accommodates runout and angle adjustments, enabling the sealing device to adapt to low-precision mounting conditions without direct rigid contact.
Solution Approach 2:
The resilient member functions as a flexible elastic element that allows the sealing device to flexibly adapt to position and angle variations. This flexible connection enables the system to tolerate mounting errors and shaft runout, expanding applicability to cost-sensitive low-precision products.
3Manufacturing precision
If space is provided for runout and angle adjustment, then the magnetic fluid sealing device can self-correct mounting errors, but the housing structure becomes more complex
Solution Approach 1:
The resilient member provides beforehand cushioning by absorbing and mitigating the effects of runout and mounting errors before they can transmit damaging forces to the magnetic fluid sealing device. This pre-cushioning effect protects the precision component from the harmful impacts of low-precision mounting.
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
Enables the application of magnetic fluid sealing devices in low-precision products by reducing fatigue damage and failure rates, ensuring effective sealing and shielding, and maintaining the service life of the devices.
Implementation Method 1
a resilient member which is hermetically connected to both the magnetic fluid sealing device and the fixed structure, wherein after the magnetic fluid sealing device is resiliently and hermetically connected to the fixed structure by the resilient member
Implementation Method 2
an outer gas blockage cavity is provided inside the housing and below the magnetic fluid sealing device, and the outer gas blockage cavity is capable of forming a gas blockage after the bottom of the housing is sealed
Data Source
AI summary
A magnetic fluid sealed shaft assembly, a shielded motor, and a shielded pump, wherein the shaft assembly comprises: a housing provided with an accommodating cavity, the accommodating cavity being provided with a fixed structure on an inner wall; a rotating shaft supported and mounted in the accommodating cavity; a magnetic fluid sealing device which is located in the accommodating cavity and sleeves and is sealedly and fixedly mounted on the rotating shaft, wherein space is reserved in the housing for runout of the magnetic fluid sealing device following the rotating shaft and/or adjustment of a mounting angle and position; and a resilient member which is sealedly mounted on an outer sleeve of the magnetic fluid sealing device and sealedly connected to the fixed structure. This structure eliminates the additional axial force, radial force, external torsion, statically indeterminate force, etc., on the bearings in the magnetic fluid sealing device during operation.