Product Overview
The KR piston seal is a double-acting sealing component consisting of a preloaded elastomeric square ring and a specially designed polyurethane sealing outer ring . The two outer sealing lips serve as the main seals, effectively containing pressure from both sides while preventing hydraulic pressure buildup across the sealing surface .
The KR seal features a robust profile designed for the most demanding operating conditions, with outstanding leak tightness and compliance . It can be installed in closed, one-piece piston designs without requiring outer ring retention during assembly .
How It Works
The KR seal operates through a combination of elastomer energization and pressure activation. The rectangular NBR energizer provides initial preload for sealing under low pressure conditions. As system pressure increases, the hydraulic fluid activates the energizer, which pushes the PU slide ring outward against the cylinder bore, creating a self-energizing sealing effect. The two outer sealing lips form the primary sealing interface, effectively containing fluid from both sides of the piston .
The support ring located in the middle of the sealing surface, along with the raised edges of the sealing lips, enhances the sealing effect by increasing contact pressure . This design ensures reliable bidirectional sealing across the full pressure range.
Specifications and Parameters
| Parameter |
Detail |
| Product Name |
KR Piston Seal |
| Type |
Double-acting combination piston seal |
| Slide Ring Material |
High-strength PU / Modified Polyurethane (Hardness ~55 Shore D) |
| Energizer Material |
NBR (Nitrile Butadiene Rubber, ~80 Shore A) |
| Color |
PU: Various / NBR: Black |
| Working Pressure |
≤ 300 bar / 30 MPa |
| Temperature Range |
-35°C to +110°C (Peak 125°C) |
| Working Speed |
≤ 0.5 m/s |
| Medium |
Mineral oil-based hydraulic fluids, PAO fluids |
| Standard |
ISO 7425-1 |
| Application |
Piston seal for double-acting hydraulic cylinders |
Product Features
1. Exceptional Sealing Performance
The KR seal provides exceptionally high static and dynamic sealing performance, ensuring reliable position retention under load . It is particularly well suited for leakage-critical applications .
2. Extreme Wear Resistance
The specially formulated polyurethane material provides outstanding wear resistance and long service life, even under harsh operating conditions .
3. High Extrusion Resistance
The robust seal profile and high-modulus PU material provide excellent resistance to extrusion, ensuring reliable performance under high pressure .
4. Insensitive to Pressure Peaks
The seal design is insensitive to pressure peaks and maintains stable performance under shock loads .
5. Low Friction Throughout Service Life
The seal maintains consistently low dynamic friction throughout its entire service life, reducing heat generation and wear .
6. Easy Installation
The compact design allows for easy snap assembly on one-piece pistons.
7. Good Sealing in Small Assembly Conditions
The KR seal provides excellent sealing performance even in extremely small assembly conditions .
8. Can Be Used for Single-Acting Applications
While designed for double-acting applications, the KR seal can also be used for single-acting applications .
