Rod seal is a very critical sealing component in hydraulic and pneumatic systems. Its performance directly determines the sealing effect and service life of the entire system.
Main functions
Prevent hydraulic oil/gas from leaking out of the cylinder along the piston rod (external sealing);
Maintain system pressure to ensure the normal operation of the hydraulic cylinder;
Often used in combination with wiper seal and buffer seal to form a complete sealing system.
Seals the piston rod as it moves in and out of the cylinder.
Prevents internal fluid (oil or gas) from leaking out of the cylinder.
Maintains system pressure integrity and operational safety.
| Feature | Description |
|---|---|
| ? Unidirectional sealing | Designed to seal pressure from the inside of the cylinder (rod-out direction). |
| ? Wiping and sealing | Works in tandem with a wiper seal to keep contaminants out and fluid in. |
| ↕️ Dynamic sealing | Capable of sealing under reciprocating motion (back and forth rod movement). |
| ? Leak-tight | High sealing performance even under high pressure and frequent cycling. |
| ? Wear-resistant | Must withstand constant friction with the rod surface over long periods. |
| ? Wide fluid & temperature compatibility | Available in materials that handle oil, water-based fluids, and compressed air, across varied temperature ranges. |
| Material | Key Benefits | Temperature Range |
|---|---|---|
| Polyurethane (PU) | High wear resistance, good elasticity | –30°C to +100°C |
| Nitrile rubber (NBR) | Excellent oil resistance, economical | –30°C to +100°C |
| FKM (Viton) | High temperature & chemical resistance | –20°C to +200°C |
| PTFE (Teflon) | Low friction, ideal for high speed | –50°C to +260°C |
| Type | Description |
|---|---|
| U-cup Seal | Most common; flexible lip for rod sealing. |
| Buffer Seal | Used in high-pressure systems, paired with rod seals to absorb pressure spikes. |
| Chevron (V-pack) Seal | Multi-piece set, suitable for heavy-duty applications. |
| Step Seal (PTFE + O-ring) | High performance; used in precise or high-pressure cylinders. |
Installed in the gland (front cover) of a hydraulic/pneumatic cylinder.
Lip must face the pressure side (usually toward the cylinder interior).
Rod surface must be smooth (Ra ≤ 0.2 μm) to prevent leakage or damage to the seal.
Usually used with wiper seal and sometimes a buffer ring.
Hydraulic cylinders (excavators, forklifts, presses)
Pneumatic cylinders (automation equipment)
Injection molding machines
Construction equipment
Industrial machinery
✔ Prevents external leakage of fluid
✔ Withstands high pressure and dynamic motion
✔ Low friction and wear-resistant
✔ Available in many designs and materials
✔ Crucial for system reliability and efficiency
Factory add:No.518 Lufu industrial Zone,Jing County,
Hengshui City,Hebei,China
Zip Code: 050000
Telephone:+86-(0311) 87510758
Phone:13331369990(Chinese)
Phone/wechat/whatsapp:13331369990 (english)
Email:info@ruisuoseal.com
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