Mechanical Seal Radial Downsizing with Damped Bellows
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Solution Overview
Problem
Conventional mechanical seals with dual bellows on radially outward and inward sides face challenges in downsizing and suppressing vibrations, leading to increased size and disturbance effects.
Innovation Solution
A mechanical seal design featuring first and second bellows that expand and contract in a central axial direction, with a damping member in a radially inward position to reduce vibration and allow for radial downsizing, where the first bellows have a smaller inner diameter than the second bellows, and a coil spring or elastic body ring is used to control expansion and contraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If bellows are doubly provided on radially outward side and radially inward side, then pressing mechanism can be formed, but size of mechanical seal increases in radial direction
Solution Approach 1:
The patent applies nesting by placing the second bellows inside the first bellows structure. The second bellows is positioned within the radial space of the first bellows, allowing both bellows to coexist without requiring additional radial clearance. This nested arrangement enables the pressing mechanism to function with dual bellows while minimizing the overall radial footprint of the mechanical seal.
2Area of stationary object
If bellows are arranged to overlap radially, then radial downsizing is achieved, but vibration of pressing mechanism increases
Solution Approach 1:
The patent introduces a damping member as an intermediary element between the first and second bellows. This damping member acts as a mediator that absorbs and dissipates vibrations generated by the overlapping bellows structure. By placing the damping member in the radial gap between the bellows, it suppresses unwanted vibrations while allowing the compact nested arrangement to be maintained, thus resolving the contradiction between radial downsizing and vibration suppression.
3Stability of the object's composition
If damping member is added to suppress vibration, then stability is improved, but device complexity increases
Solution Approach 1:
The patent employs a damping member constructed from flexible damping material that can be formed as a ring or cylindrical structure. This flexible damping component is integrated into the radial gap between the bellows, providing vibration suppression functionality without requiring complex mechanical assemblies. The use of flexible damping material allows the component to be relatively simple in structure while effectively addressing vibration issues, thus minimizing the increase in device complexity.
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 configuration achieves radial downsizing while effectively suppressing vibrations and reducing disturbance effects, maintaining sealing functionality and stability.
Implementation Method 1
the first bellows and the second bellows expand and contract in a central axial direction of the rotating shaft in accordance with fluid pressure inside the sealed space
Implementation Method 2
a damping member which suppresses vibration of the pressing mechanism is provided on the radially inward side of the first bellows
Data Source
Figure 1
Figure 2
AI summary
Provided is a mechanical seal, in which a pressing mechanism configured such that two bellows expand and contract in accordance with fluid pressure inside an annular sealed space that is formed by the two bellows is included, that enables downsizing in a radial direction. A mechanical seal (100) is configured such that an annular sealed space (S1) is formed by a first bellows (141), a second bellows (151), and members respectively provided on both end sides of the first bellows (141) and the second bellows (151), and that the first bellows (141) and the second bellows (151) expand and contract in a central axial direction of a rotating shaft (200) in accordance with fluid pressure inside the sealed space (S1). The first bellows (141) and the second bellows (151) are arranged at positions distant to each other in the central axial direction, and are arranged such that a part of the first bellows (141) on a radially inward side and a part of the second bellows (151) on a radially outward side overlap when viewed in the central axial direction.