Mechanical Seal Integrating Bearing and Sealing Functions
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Solution Overview
Problem
Conventional mechanical seal arrangements in electric water pumps face issues such as high cost, power loss, and complexity due to the need for additional bearings and axial movement of seal rings, which complicates replacement and increases the risk of bearing damage and water leaks.
Innovation Solution
A mechanical seal arrangement where the rotating shaft is supported solely by a stationary-side seal ring, eliminating the need for additional bearings and axial movement, with a thrust ring and fluid introducing means to enhance sealing and reduce friction, thereby simplifying the structure and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rotating shaft is supported by both a ball bearing and a sliding bearing (sleeve), then the shaft rotation is stable, but the device complexity and cost increase
Solution Approach 1:
The patent combines the functions of the ball bearing and sliding bearing into a single integrated bearing structure. The bearing includes an outer ring with a first sliding surface and an inner ring with a second sliding surface, where the rotating shaft contacts the second sliding surface. This merged structure eliminates the need for separate ball bearing and sleeve components while maintaining rotational stability through fluid lubrication between the sliding surfaces.
2Ease of repair
If the stationary-side seal ring is made axially movable to accommodate wear, then the seal can be adjusted, but the bearing performance becomes unstable and radial clearance increases
Solution Approach 1:
Instead of making the stationary-side seal ring axially movable to accommodate wear, the patent inverts the approach by making the rotating-side seal ring axially movable while keeping the stationary-side seal ring fixed. The rotating-side seal ring is pressed by a spring against the rotating shaft, allowing it to move axially to accommodate wear on the sealing surface. This inversion maintains stable bearing performance by keeping the stationary-side seal ring fixed, eliminating radial clearance variations.
3Reliability
If the large-diameter portion of the rotating shaft is worn, then the seal function deteriorates, but the entire shaft must be replaced causing high cost
Solution Approach 1:
The patent segments the seal structure into a separate rotating-side seal ring that can be independently replaced from the rotating shaft. The rotating-side seal ring is fitted on the large-diameter portion of the rotating shaft and can be axially moved. When wear occurs on the sealing surface, only the seal ring needs to be replaced, not the entire shaft, significantly reducing replacement cost and improving ease of maintenance.
4Reliability
If a seal mechanism is added to the electric water pump, then sealing performance improves, but the device complexity and cost increase
Solution Approach 1:
The patent implements a mechanical seal structure where the stationary-side seal ring and rotating-side seal ring work together to provide sealing between the motor chamber and pump chamber. The stationary-side seal ring is fixed to the housing with its sealing surface facing the rotating shaft, while the rotating-side seal ring moves axially and contacts the rotating shaft. This multi-functional seal structure provides reliable sealing while maintaining relatively simple construction compared to traditional separate seal and bearing arrangements.
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 reduces the size and cost of the device, stabilizes the bearing performance, prevents seal damage, and minimizes power loss by using a small-sized magnet, while ensuring reliable sealing and extended device life through reduced friction and improved lubrication.
Implementation Method 1
the stationary-side seal ring has a sliding surface supporting the rotating shaft in both a radial direction and a thrust direction
Implementation Method 2
a fluid introducing means for reducing friction between sliding surfaces and introducing fluid into the radial sliding surfaces of the stationary-side seal ring and the rotating shaft
Data Source
Figure 1
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Figure 3
AI summary
Provided is a mechanical seal that eliminates the need to provide an additional bearing, enables size reduction and cost reduction, and can provide stable performance as a bearing. A stationary-side seal ring 20 is disposed on the high-pressure fluid side of a rotating-side seal ring 21, and fixed to a housing 1 and has sliding surfaces 20a, 20c, and 20d supporting a rotating shaft 2 in both a radial direction and a thrust direction. The rotating-side seal ring 21 is axially movably fitted by an urging means 25 fitted on the rotating shaft 2. The rotating shaft 2 has an outer peripheral surface 2a contacting and sliding on the radial sliding surface 20a of the stationary-side seal ring 20 to be supported radially. Thrust rings 10a and 10b are provided between the stationary-side seal ring 20 and the rotating shaft 2, for supporting the rotating shaft 2 in thrust directions.