☰
Matched X-ring and Y-ring seal groups for heavy-load, high-speed rotation in construction and mining machinery.
When reviewing an old part, always ask: is it DO, DF, XY or a loose seal ring? XY type denotes a catalogued seal group of complementary halves: one X-ring and one Y-ring, each with its own groove depth and section, plus two toric elastomer loaders (e.g. SC 0760 X + SC 0760 Y). They are not two identical DO rings — X and Y must be ordered and installed as a factory-matched pair.
XY sits in the O-ring-loader family but is specified for heavier load and higher peripheral speed positions: scraper-conveyor reducers, shearer transmissions, large crawler hubs and auxiliary bearing seals on mixers and industrial drives. Rings use FC15Cr3Mo alloy (approx. 15% Cr, 2–4% Mo), heat-treated to HRC 65–72, with faces lapped for stable contact-band pressure in abrasive mud, mine dust and water splash.
| Product type | XY floating seal group (X-ring + Y-ring + 2 elastomer loaders) |
|---|---|
| Ring designation | X half and Y half are catalogued separately but supplied and installed as one matched group |
| Ring material | FC15Cr3Mo chrome-molybdenum alloy cast iron |
| Face quality | Flatness to ~0.01 mm; face roughness controlled within ~0.07 µm Ra class |
| Operating limits | Max. ~0.3 MPa; circumferential speed up to ~3 m/s; -40 °C to +200 °C (elastomer-dependent) |
| Typical applications | Excavator and bulldozer undercarriage, scraper conveyors, shearers, reducers, mixers, auxiliary bearing seals on harsh-duty machines |
X/Y pairing logic, catalog sizing and duty limits. Scroll inside the bordered panel.
| What “X” and “Y” mean | Two different ring halves in one seal group; groove depth and section differ (e.g. 22 mm vs. 10.5 mm pocket depth on the same OD catalog line) |
|---|---|
| Relationship to DO type | XY is a heavy-duty variant within the O-ring-loader floating seal family; elastomer is still typically a toric O-ring on each half |
| Complete group contents | 1× X-ring + 1× Y-ring + 2× elastomer loaders (NBR, HNBR, FKM or silicone per duty) |
| Example catalog notation | SC 0760 X / SC 0760 Y — same group OD (~93.3 mm) with complementary I.D. and groove dimensions |
| OEM example | Caterpillar 6V2733 class XY seal groups for loader chassis and similar heavy-machine positions |
| Alloy chemistry | ~15% Cr, 2–4% Mo, balance Fe/C; high carbide hardness for abrasive wear resistance |
| Heat treatment | Quench/temper to HRC 65–72; distortion controlled before final lapping |
| Why XY vs. standard DO | Specified when OEM drawing calls for asymmetric X/Y pairing or when heavier load/speed rating is required on the same machine platform |
| Peripheral speed | Reference maximum ~3 m/s with oil lubrication; reduce speed or increase lubricant cooling if face temperature rises |
| Pressure | Seal is normally pressure-free in rotation; static differential references up to ~0.3 MPa for standard cast-iron grades |
| Size range | Outer diameter approx. 45 mm to 1,425 mm across catalog; custom sizes from drawing or worn sample |
| Lubrication | Hub oil or grease must wet the lapped faces; wedge clearance from I.D. aids oil feed to the contact band under rotation |
| Contaminants excluded | Mud, water, mine dust, sand and slurry splash — typical undercarriage and conveyor environments |
| Machine brands (examples) | Komatsu, Caterpillar, Volvo, Hitachi, Hyundai, Kobelco, Shantui and other crawler OEM platforms |
| Mining equipment (examples) | Scraper conveyor sprockets and reducers, shearer transmission, continuous-miner head drives |
| Industrial duty (examples) | Gearbox auxiliary seals, concrete mixers, ship deck machinery, wind-turbine gear units where XY group is specified |
| Ordering rule | Always order and replace the X and Y halves together with both elastomers — never mix X/Y sizes from different catalog lines |
| Inquiry data | OEM part number, machine model, seal group OD, X/Y marking on old ring, quantity, elastomer fluid exposure |
Select by install position + contamination + failure history. XY is not a “large bore only” label — it is a defined X/Y pairing on the drawing.
Final drives, track rollers and idlers on excavators and bulldozers (D50–D355 class) where OEM drawings specify XY seal groups.
Scraper-chain reducers and cutter transmission hubs see continuous abrasive load; 15Cr3Mo rings extend rebuild intervals between overhauls.
Mixers, conveyors and auxiliary bearing positions on concrete and material-handling plant when maintenance access is difficult and long seal life is required.
Photograph the ring marking or send the worn group — we will match the correct XY catalog line.
Contact us
