Compact Seal Packing With Radial Spring Layout for Low Axial Bulk
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Solution Overview
Problem
Existing seal packings for rotary shafts are bulky and complex, requiring stringent manufacturing tolerances to ensure sealing while allowing for friction ring slipping, which complicates their production and increases costs.
Innovation Solution
A compact seal packing design featuring a friction ring with a continuous cylindrical outer surface, a transmission element with radial flanges, and a compression spring that extends partially around the friction ring, allowing force transmission without the need for precise tolerances, and incorporating a secondary sealing element to enhance sealing and slipping functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the spring element is located on the side of the friction ring opposite to the rotor, then the sealing function is maintained, but the axial bulk of the seal packing becomes relatively significant
Solution Approach 1:
The invention repositions the spring element from the traditional axial location (opposite side of friction ring) to a radial location (substantially at the level of the friction ring in a radial plane). This dimensional change from axial to radial arrangement allows the spring to exert force on the friction ring without increasing axial bulk, thereby resolving the contradiction between maintaining sealing function and reducing axial dimensions.
2Length of stationary object
If the spring element is located substantially at the level of the friction ring in a radial plane, then the axial bulk is reduced, but the friction ring becomes relatively complex requiring a step along the radial direction
Solution Approach 1:
The invention introduces a transmission element as an intermediary component between the spring element and the friction ring. The transmission element has a cylindrical wall with first and second radial flanges that facilitate force transmission from the spring to the friction ring. This intermediary structure simplifies the friction ring design by eliminating the need for complex radial steps, while still achieving compact axial dimensions.
3Reliability
If a gasket is sandwiched radially between the friction ring and a portion of the case, then sealing is achieved, but stringent compliance with manufacturing tolerances is required
Solution Approach 1:
The invention employs a secondary sealing element that extends partially between the transmission element and the friction ring, and partially between the supporting ring and the case. This self-contained sealing arrangement within the transmission element structure provides sealing functionality without requiring stringent manufacturing tolerances on the friction ring and case interfaces, allowing the system to self-accommodate manufacturing variations.
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 design results in a significantly reduced axial bulk and simplified manufacturing process, achieving effective sealing and slipping without stringent tolerance requirements, making the seal packing more compact and cost-effective.
Implementation Method 1
a compression spring bearing against a transmission element... the compression spring thus extends at least partially at the cylindrical portion of the friction ring, the force transfer resulting from the cooperation of the second flange and of the cylindrical portion of the transmission element with the friction ring and allowing for a proper transmission of the forces exerted by the spring to the friction ring
Implementation Method 2
a counter-ring having an axis of symmetry coincident with the X axis and a radial friction surface bearing against one of the radial surfaces of the friction ring
Data Source
AI summary
The invention relates to a compact seal packing (10), ensuring dynamic sealing between a rotary shaft and a stationary body, in particular a stationary enclosure. In particular, the seal packing (10) comprises a compression spring (16) bearing against a transmission element (18) to transmit the forces of the spring to a friction ring (12) and press it against a counter-ring (14). The compression spring (16) is bearing against a first radial flange (181) of the transmission element (18), a second flange (182) of the transmission element (18) being located partially facing a radial surface (122) of the friction ring distant from the counter-ring (14) and a cylindrical wall (180) of the transmission element (18) being located partially facing the cylindrical outer surface (124) of the friction ring (12).