Mechanical Seal Structure for Shaft Vibration and Compact Sealing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional mechanical seals face challenges in providing reliable sealing properties when shaft vibration increases, as the seal ring is restrained by contact points, and in maintaining a compact device size by increasing the axial length of the rubber bellows.
Innovation Solution
A mechanical seal design where the seal member is regulated by the holding part of the case to contact the stationary-side sealing ring at one point, allowing it to follow the movement of the rotating-side sealing ring while maintaining reliable sealing properties, and incorporating an axial gap to absorb deformation and a trapezoidal cross-sectional shape to facilitate compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the O-ring contacts the seal ring at two points (inner circumferential surface and end surface), then the seal ring is restrained from moving, but the seal ring cannot sufficiently follow the movement of the mating ring when shaft vibration is increased, compromising sealing properties
Solution Approach 1:
The invention extracts the sealing function from the O-ring by removing its contact with the seal ring. Instead, a dedicated seal member (such as a lip seal or contactless seal element) is introduced to perform solely the sealing function, while the O-ring is retained only for its original purpose of preventing fluid ingress into the annular case. This separation allows the seal ring to move freely with shaft vibration without being restrained by the O-ring, yet still maintain reliable sealing through the specialized seal member.
Solution Approach 2:
The invention introduces a seal member as an intermediary element between the seal ring and the sealing interface. This seal member (such as a lip seal, contactless seal, or dedicated sealing element) mediates the sealing function without imposing mechanical constraints on the seal ring's movement. The seal member accommodates shaft vibration and seal ring displacement while maintaining the sealing barrier, thus resolving the contradiction between restraint and adaptability.
2Reliability
If the axial length of the rubber bellows is increased to ensure flexibility and allow the stationary-side sealing ring to follow movement, then the sealing reliability is improved, but the mechanical seal device is increased in size
Solution Approach 1:
The invention replaces the bulky rubber bellows with a flexible seal member such as a lip seal or elastic sealing element that can accommodate axial displacement and shaft vibration. These flexible sealing elements achieve the necessary compliance and movement accommodation in a compact form factor, eliminating the need for long axial bellows while maintaining the ability of the stationary-side sealing ring to follow the rotating-side sealing ring's movement during vibration.
Solution Approach 2:
The invention changes the design parameters of the sealing system by transitioning from a bellows-based flexible accommodation mechanism to a seal-member-based approach. This parameter change involves selecting seal members with appropriate material properties (such as lip seal rubber compounds or elastic sealing materials) that provide the necessary flexibility and movement accommodation without requiring increased axial length, thus achieving compact dimensions while maintaining sealing reliability under vibration conditions.
Data Source
Figure 1
Figure 2
Figure 3(A)~3(B)
AI summary
The purpose of the present invention is to provide a mechanical seal in which a stationary-side sealing ring can follow the movement of a rotating-side sealing ring to provide reliable sealing properties and by which the entire device can be made compact. A mechanical seal in which a rotating-side sealing ring 13 attached to a shaft 2 and a stationary-side sealing ring 21 attached to a housing 3 slide relative to each other and seal between the housing 3 and the shaft 2 includes a case 22 which is attached to the housing 3 and which contains the stationary-side sealing ring 21, and a seal member 23 which is disposed between the case 22 and the stationary-side sealing ring 21, and the case 22 includes a holding part 22d which regulates the seal member 23 from moving to both sides in the axial direction thereof.