Rexnord ZLF6000 Split Housed Bearings
The ZLF6000 is categorized as a Split Housed Bearing. Unlike the standard pillow blocks (ZAF) we discussed earlier, which are a solid one-piece casting, the ZLF housing is literally cut in half.
The Design: As described in the catalog, the ZLF6000 features a Cast Iron Split Housing. It comes apart vertically.
The Application: Imagine a shaft that has a coupling on one end and a heavy impeller on the other. You can’t slide it out. With a ZLF, you simply unbolt the housing cap, place the two halves around the shaft, bolt them back together, and you’re done.
The Trade-off: While solid housings (ZAF) generally offer slightly higher rigidity, the split housing (ZLF) offers a massive advantage in serviceability. It transforms a job that requires a crane into a job that requires a wrench
| Size Code | Bore Diameter (Inch) | Type | Part Number (Fixed) | Part Number (Expansion) | Max Expansion |
|---|---|---|---|---|---|
| 14 | 5-7/16" | Fixed | ZLF6507F | ZLFS6507F | 3/4" |
| 15 | 5-15/16" | Fixed | ZLF6515F | ZLFS6515F | 3/4" |
| 16 | 6-7/16" | Fixed | ZLF6607F | ZLFS6607F | 3/4" |
The "F" Suffix: Unlike the standard pillow blocks (which often don't require the "F" for 2-bolt), the ZLF series part numbers explicitly include the "F" suffix. According to the catalog nomenclature (Page 14), this denotes a 4-Bolt Housing. This makes sense because a split housing needs the extra clamping force provided by four bolts to keep the two halves tightly mated under load.
The catalog notes an Expansion of 3/4 inch for these units. This is significantly larger than the standard 3/8" found in smaller pillow blocks. This large take-up range is essential for accommodating thermal expansion in large, heavy machinery or for adjusting belt tension in massive drive systems.
The "S" Variant: Notice the part number variation (ZLFS). The "S" in the middle denotes a Floating/Expansion type housing. If your shaft expands significantly with heat or if you need to adjust the position of the housing on the frame, you would use the ZLFS model paired with a fixed ZLF on the other side of the shaft.
While the ZLF6000 is designed for heavy loads, it doesn't neglect contamination protection.
The catalog notes that these units feature Field Interchangeable Seals. Given that these bearings are often found in dirty environments (mining, aggregates, recycling), you can specify the heavy-duty seals (Type M or Type G) that we discussed in the first article to keep water and grit out.
