FSM type piston rod special seal

FSM-Type Piston Rod Seal

Friction-Synergized Multi-Lip Integral Wiper Seal


1. Product Overview

The FSM-Type Piston Rod Seal is an integrated, low-friction sealing solution that combines primary sealing and contaminant exclusion into a single, compact unit. Featuring the innovative FSM (Friction-Synergized Multi-Lip) architecture, this seal is engineered to deliver zero-leakage performance while significantly reducing dynamic friction, efficiently scraping contaminants, and extending overall system service life.

2. Core Technological Innovations

2.1 Low-Friction Synergistic Lip System

  • Primary Sealing Lip: Incorporates a progressive pressure-compensating profile that ensures uniform contact stress distribution as pressure increases, preventing localized overloading.

  • Secondary Guiding Lip: Features micro-lubrication channels to maintain a stable lubricating film, minimizing breakaway and running friction (dynamic friction coefficient as low as 0.08-0.15).

  • Dual-Lip Synergy: The interaction between the primary and secondary lips creates a hydraulic pressure-balancing zone, effectively suppressing stick-slip phenomena.

2.2 Integrated Intelligent Wiper System

  • Front Wiper Blade: Employs a multi-stage, progressive scraping profile (3-stage design with 25°/45°/70° angles) for efficient contaminant removal.

  • Contaminant Reservoir: A dedicated chamber temporarily stores scraped particles to prevent re-ingression into the system.

  • Self-Adjusting Elastomer: The wiper blade utilizes a variable-durometer composite material—a soft base for excellent rod conformity and a reinforced edge for effective scraping.

2.3 Thermal Management & Extrusion Resistance

  • Heat-Dissipating Fin Structure: Micro-channels integrated into the seal’s back facilitate efficient heat transfer away from the sealing zone.

  • Dual Anti-Extrusion System: Combines a one-piece anti-extrusion ring with zoned reinforcement, capable of withstanding gaps up to 0.4mm.

3. Material Options

Code Base Material Temperature Range Key Characteristics
FSM-HPU High-Performance Polyurethane -40°C to +110°C Excellent abrasion resistance, general-purpose
FSM-XP Engineered PTFE Compound -60°C to +200°C Ultra-low friction, superior chemical resistance
FSM-HNBR Hydrogenated Nitrile Butadiene Rubber -50°C to +150°C Outstanding oil and fuel resistance
FSM-FKM Fluorocarbon Elastomer -20°C to +200°C High-temperature and chemical resistance

4. Performance Specifications

Parameter Range Test Standard
Dynamic Pressure Range 0 – 35 MPa ISO 5597/1
Static Pressure Range 0 – 45 MPa ISO 5597/1
Operating Speed ≤ 2.5 m/s DIN 3761
Friction Coefficient 0.08 – 0.25 ASTM D1894
Leakage Rate < 0.05 ml/h ISO 7986
Service Life (Travel) > 5,000 km Accelerated Life Testing

5. Typical Applications

  • High-Precision Servo-Hydraulic Systems with stringent friction stability requirements.

  • Frequent Start-Stop Cycles: Hydraulic cylinders in injection molding and die-casting machines.

  • Dusty/Contaminated Environments: Construction, mining, and agricultural equipment.

  • Extreme Temperature Applications: Arctic equipment, metallurgical machinery.

  • Long-Stroke Cylinders: Large-scale presses, ship steering gear.

6. Installation & Design Guidelines

6.1 Mating Surface Requirements

  • Piston Rod Hardness: ≥ HRC 45

  • Surface Finish: Ra 0.1 – 0.4 µm

  • Straightness: ≤ 0.1 mm/m

  • Surface Treatment: Hard chrome plating (20-30 µm) or ceramic coating recommended.

6.2 Installation Instructions

  • Use a dedicated FSM installation tool (1:10 taper).

  • Lubricate the sealing lips with the system’s hydraulic fluid prior to installation.

  • Ensure the seal is not twisted or overstretched in the gland.

  • Perform a running-in period of 5-10 full, unloaded strokes after installation.

6.3 Gland Design Specifications

  • Requires FSM-specific gland dimensions (differs from standard Glyd-Ring® or Step Seal glands).

  • Groove Bottom Radius: R0.2 ± 0.05 mm

  • Lateral Clearance: 0.1 – 0.2 mm

  • Groove Surface Finish: Ra ≤ 1.6 µm

7. Key Advantages

  1. Compact Integrated Design: Combines sealing and wiping functions, reducing required installation space by up to 30%.

  2. Intelligent Friction Management: Adapts contact pressure based on system conditions, reducing energy consumption by 15-25%.

  3. Environmental Robustness: Specialty compounds maintain elastomeric properties across extreme temperatures.

  4. Extended Service Life: Optimized stress distribution delivers over 50% longer service life compared to conventional rod seals.


8. Technical Notes

The FSM (Friction-Synergized Multi-Lip) technology is our proprietary sealing architecture. Its core principle is achieving the optimal balance between friction performance and sealing effectiveness across diverse operating conditions through synergistic multi-lip interaction and specialized geometrical design. This product is protected by multiple international patents (Pat. No.: FSM-PT2023-001 to 005). Comprehensive type test reports and service life predictions are available upon request.

Original source: Hydraulic seal https://www.bszzseal.com/