Polyimide Thin Floating Seal Ring: A High-Performance Sealing Solution for Motor Sliding Bearings

In the field of sealing for sliding bearings in large and medium-sized motors, traditional sealing materials often struggle to simultaneously meet the multiple requirements of high insulation, high-temperature resistance, wear resistance, and minimal shaft wear. The polyimide thin floating seal ring (hereinafter referred to as PI thin floating seal ring), utilizing aerospace-grade thermoplastic engineering polyimide material PI-YS20, offers a highly reliable and high-performance sealing solution for the motor industry.

Core Material Advantages

The PI thin floating seal ring is made from aerospace-grade thermoplastic engineering polyimide material PI-YS20. This material possesses the following outstanding properties:

• Excellent high insulation performance: Effectively isolates current in high-voltage environments, preventing electrical leakage and breakdown.
• Superior wear resistance and self-lubricating properties: Significantly reduces the friction coefficient and maintains extremely low wear rates even under dry friction or boundary lubrication conditions.
• Outstanding high-temperature resistance: Capable of long-term stable operation in elevated temperature environments, meeting the thermal loads generated during the operation of large and medium-sized motors.
• Excellent dimensional stability: Low coefficient of thermal expansion ensures minimal dimensional change under temperature variations, maintaining stable sealing clearances over time.
• Non-abrasive to the shaft: Causes extremely low wear on the mating shaft surface, effectively protecting shaft journal precision and extending service life.

These characteristics make PI-YS20 an ideal upgrade and replacement for traditional sealing materials such as packing (gland packing), rubber, and ordinary engineering plastics.

Structural Design Features

The polyimide thin floating seal ring features a unique two-half-ring structure design, primarily consisting of the following components:

1. Two-half-ring body: Precision-machined for easy on-site installation and disassembly, particularly suitable for motor maintenance scenarios where major disassembly is not required.
2. Locating pins: Ensure precise positioning of the two half-rings after assembly, preventing relative rotation or misalignment and keeping the sealing surfaces in optimal contact.
3. Spring grooves: Incorporate built-in spring structures that provide appropriate radial compensation force according to actual operating conditions. This allows the seal ring to “float” and adapt to minor shaft runout and thermal deformation, maintaining a stable sealing gap.

This thin floating design combines rigidity and flexibility, ensuring sealing reliability while reducing installation difficulty and maintenance costs.

Primary Applications and Use Cases

The PI thin floating seal ring is mainly used in the following applications:

• Steam seal cover sealing: Effectively prevents lubricating oil leakage and external contaminants from entering the bearing chamber, protecting the sliding bearing system.
• Vertical motor sliding bearing sealing: Particularly suitable for large and medium-sized vertical motors, addressing sealing challenges caused by axial loads and radial runout in vertical shaft systems.
• Replacement for traditional packing “insulation tape” seals: Compared with conventional gland packing seals, the PI thin floating seal ring offers longer service life, lower friction loss, and superior insulation performance.

In addition, according to actual working conditions, the M/Z series thin floating seal rings can be used in combination with polyimide floating labyrinth oil seals to form a composite sealing system, further enhancing overall sealing effectiveness and reliability. This combined solution has been widely validated in large motor applications and can significantly reduce downtime risks and maintenance frequency caused by seal failure.

Technical Performance Summary

The core competitiveness of the polyimide thin floating seal ring lies in the perfect integration of its advanced material and innovative structure:

• Aerospace-grade PI-YS20 material ensures stability under extreme operating conditions;
• Thin two-half-ring floating structure balances excellent sealing performance with ease of installation and maintenance;
• Suitable for critical sealing positions such as steam seal covers and vertical motors, effectively replacing traditional sealing methods.

As industrial equipment continues to develop toward larger scale, higher speeds, and greater intelligence, the requirements for reliability, service life, and insulation performance of sliding bearing seals are increasing. With its superior comprehensive performance, the polyimide thin floating seal ring is becoming the preferred solution for sealing technology upgrades in large and medium-sized motors, providing a solid guarantee for the stable and efficient operation of the motor industry.

This technology not only represents an advancement in materials science but also delivers reliable sealing support for high-end equipment manufacturing, demonstrating broad market application prospects.