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PU UN Series Seals (UPI/USI/UN/U601) Product Description

PU UN Series Seals (UPI/USI/UN/U601) Product Description

  • Overview
  • Inquiry
  • Related Products
  • Core Performance Parameters

Item

Specification

Main Material

High-quality Polyurethane (PU). PPDI modified PU is optional for tough working conditions

Seal Type

U-shaped lip, self-tightening

Movement Type

Reciprocating linear motion for hydraulic / pneumatic systems

Groove Standard

ISO 3601 / GB/T 15242

Temperature Range

-30℃ ~ 120℃. It can stand 130℃ for a short time

Working Pressure

0~40 MPa. Use PTFE back-up ring if pressure > 20 MPa

Reciprocating Speed

≤ 0.5 m/s (normal use); ≤ 0.3 m/s (high pressure > 30 MPa)

Applicable Media

 Mineral hydraulic oil, synthetic hydraulic oil, water-glycol, phosphate ester hydraulic oil, industrial grease, etc

Main Material Features

Oil-resistant, wear-resistant, high tear resistance, hydrolysis-resistant, low compression set, self-tightening sealing compensation

Medium Temperature

Same as the seal temperature range: -30℃ ~ 120℃

  • Model Performance & Application Table

Model

Applicable Parts

Core Performance & Features

Groove Fit

Typical Applications

UN

Piston / piston rod (general use)

Standard general type, single lip, self-tightening, easy to install, cost-effective

ISO 3601 standard shallow groove

Basic seals for engineering machinery, hydraulic stations, small hydraulic presses

UPI

Hydraulic cylinder piston (only)

For piston use, double lip, anti-extrusion, anti-eccentric load, stable under high pressure

ISO 3601 standard piston groove

Pistons for injection molding machines, large hydraulic presses, forging equipment

USI

Hydraulic cylinder piston rod (only)

For piston rod use, thick wear-resistant lip, anti-scour, anti-dust, anti-rolling lip

ISO 3601 standard piston rod groove

Piston rods for excavators, cranes, loaders, mining machinery

U601

Piston / piston rod for high-precision systems

Upgraded PU formula, low-friction lip, low resistance, low heat, good high-pressure performance

High-precision hydraulic system standard groove

High-precision CNC machines, automotive brake systems, servo hydraulic cylinders

3. Installation and Usage Rules

  1. Installation direction: The lip opening must face the pressure side. Use PTFE back-up ring if pressure > 20 MPa.
  2. Pre-installation: Clean the cylinder, piston, rod and groove. Remove sharp edges and burrs. Lubricate the seal with hydraulic oil or grease. Do not use sharp tools.
  3. Installation accuracy: Keep coaxiality ≤ 0.05 mm. Avoid distortion or squeezing.
  4. Daily maintenance: Check the seal regularly. Replace it if the lip is worn, broken or deformed. Clean the system when replacing.
  5. Storage: Store at 5℃~25℃, dry and ventilated. Keep away from sunlight, rain, oil, acid, alkali and chemicals. Shelf life: 12 months.

4. Core Product Advantages

  1. Full models: Covers general, piston-only, rod-only and high-precision types.
  2. High-quality material: Custom PU material, optional PPDI modified type. Works well in tough conditions.
  3. Easy replacement: Fits standard grooves. Can replace most similar seals directly.
  4. Stable sealing: Self-tightening lip works better under higher pressure. Reduces oil leakage.
  5. Longer life: Optimized structure resists extrusion, eccentric load and rolling. Lowers maintenance.

 5. Applicable Conditions

This series is widely used in engineering machinery, metallurgy, plastic machinery, machine tools, mining machinery and automotive hydraulic systems.

It works well in dusty, humid, high-pressure and high-frequency reciprocating environments.

Not suitable for high-speed rotation or strong corrosive media (strong acid, strong alkali, strong solvent).

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