Rotary Sealing Device Torque Reduction High Pressure
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Solution Overview
Problem
Existing sealing apparatuses for rotating parts under high fluid pressure suffer from unstable sealing performance due to insufficient contact between the backup ring and the groove bottom, leading to reduced effectiveness of the elastic restoring force and increased torque.
Innovation Solution
A sealing apparatus with a backup ring having a cylindrical contact surface against the groove bottom and a toric convex surface against the seal ring, ensuring constant contact and effective pressing force, combined with a seal ring designed for reduced friction and wear resistance, utilizing a D-ring made of rubber and a resin ring made of polyethylene or polyamide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an O-ring is used as the backup ring, then the sealing apparatus can be manufactured easily, but the contact between the backup ring and the bottom surface of the annular groove becomes insufficient under high fluid pressure, leading to unstable sealing performance
Solution Approach 1:
The patent changes the geometric parameters of the backup ring by providing a cylindrical contact surface instead of a flat surface. This parameter change ensures that the backup ring maintains full contact with the bottom surface of the annular groove even under high fluid pressure, as the cylindrical surface conforms to the groove geometry and prevents fluid infiltration that would occur with flat-surfaced O-rings.
2Reliability
If the seal ring is pressed against the other member to achieve sealing, then sealing performance is improved, but the frictional resistance increases and torque of the rotating portion increases
Solution Approach 1:
The patent applies curvature to the contact surfaces by providing a toric convex surface on the seal ring that contacts the other member. This curved surface geometry reduces the contact area and distributes the pressing force more effectively, maintaining sealing performance while reducing frictional resistance compared to flat contact surfaces.
3Force
If the backup ring is made elastic to provide restoring force, then the seal ring can be pressed towards the other member, but under high fluid pressure the space between the backup ring and groove bottom increases, reducing the effectiveness of the elastic restoring force
Solution Approach 1:
The patent transitions from a two-dimensional flat contact interface to a three-dimensional cylindrical contact interface between the backup ring and the groove bottom. This dimensional change allows the backup ring to maintain contact across the entire cylindrical surface area, preventing fluid infiltration and ensuring that the elastic restoring force remains effective even under high fluid pressure conditions.
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 solution provides stable and high sealing performance even under high fluid pressure by maintaining effective contact and reducing torque through reduced frictional resistance, while minimizing wear and ensuring durability.
Implementation Method 1
there may be a case where an elastic restoring force of the backup ring 14 does not effectively act as a pressing force that urges the seal ring 15 towards the second member 12
Implementation Method 2
a frictional resistance between the seal ring 15 and the second member is reduced
Data Source
Figure 1A~1B
Figure 2A~2B
AI summary
Provided is a sealing apparatus which can reduce the torque of a rotary portion while always exhibiting a stable and high sealing performance even when a high fluid pressure is being applied. A seal ring (4) inclines when subjected to a hydraulic pressure (P) and a pressing force by a D-ring (3), and stabilizes in a state where an entire opposite pressure-side taper surface (4c) is in contact with an opposite pressure-side side surface (5b) of an annular groove for sealing (5). With the hydraulic pressure (P) being applied to a portion (4b1) of the inner peripheral surface (4b) of the seal ring (4) where an operating oil comes into contact, a space between the portion (4b1) and a shaft (2) is enlarged, and an area of contact between the seal ring (4) and the shaft (2) is reduced. Thus, the torque can be reduced. Furthermore, since the outer peripheral surface (3a) of the D-ring (3) is a surface having a cylindrical shape, the operating oil is not allowed to enter between the D-ring (3) and a bottom surface (5a) of the annular groove for sealing (5) even when the hydraulic pressure (P) is being applied, and the entirety of the outer peripheral surface (3a) of the D-ring (3) always remains in contact with the bottom surface (5a) of the annular groove for sealing (5). Thus, the sealing device always exhibits a stable sealing performance.