Guide Rings
Guide Rings WR — Wear Rings
WR-type guide rings (wear rings) absorb radial side loads inside hydraulic cylinders, preventing metal-to-metal contact between piston and bore or between rod and gland — the primary cause of premature seal failure and cylinder scoring.
Function
Why Guide Rings Are Essential
In any hydraulic cylinder subjected to side loads — excavator arms, press platens, crane booms — the piston or rod is pushed against one side of the bore. Without guide rings, the metal surfaces contact directly, causing:
- Scoring of the cylinder bore or rod surface
- Accelerated seal wear from uneven loading
- Stick-slip and jerky cylinder motion
- Premature cylinder failure
WR guide rings centre the piston and rod, absorbing these loads without galling or excessive friction.
Materials
Guide Ring Materials
| Material | Max Load | Max Speed | Temperature | Best For |
|---|---|---|---|---|
| PTFE + Bronze | High | 15 m/s | −200 to +260 °C | General hydraulics, heavy load, low friction |
| PTFE + Carbon | Medium | 15 m/s | −200 to +260 °C | Chemical resistance, food/pharma |
| PTFE + Glass Fibre | Medium | 15 m/s | −200 to +260 °C | Cost-effective for moderate loads |
| Phenolic Resin (Fabric) | Very High | 5 m/s | −40 to +130 °C | Very heavy side loads, large cylinders |
| Polyamide (PA) | Medium | 5 m/s | −40 to +110 °C | Low cost, light to medium duty |
Sizes
Standard Sizes
WR guide rings are available in standard metric sizes for piston and rod applications:
- Rod guide rings: Ø 12 – 500 mm bore
- Piston guide rings: Ø 25 – 1000 mm bore
- Profiles: Split ring, spiral wound, solid ring