The SA57 hollow shaft gear reducer gives machine builders the fastest possible mounting: the driven shaft slides straight into the hollow output bore, keyed or with a shrink disc, and the torque arm takes the reaction. Internally it is the proven two-stage helical-worm arrangement of the SF series - compact, quiet and built to the standard interface dimensions of the SA57 frame family.
Hollow Shaft Advantage
- No coupling, no extra alignment: the reducer sits directly on the machine shaft
- Torque arm absorbs reaction forces; multiple arm positions simplify installation
- Compact 57 mm centre distance fits tight machine frames and overhead drives
- Efficiency 94%~96% thanks to the helical input stage
- Smooth 60~68 dB operation - suitable for packaging and assembly areas
Technical Data
| Housing material | Cast iron/Ductile iron |
| Housing hardness | HBS190-240 |
| Gear material | 20CrMnTi alloy steel |
| Surface hardness of gears | HRC58~62 |
| Gear core hardness | HRC33~40 |
| Input / Output shaft material | 42CrMo alloy steel |
| Input / Output shaft hardness | HRC25~30 |
| Machining precision of gears | precision grinding, grade 6~5 (ISO 1328) |
| Lubricating oil | GB L-CKC220~460 / Shell Omala 220~460 |
| Heat treatment | tempering, cementit-ing, quenching, etc. |
| Efficiency | 94%~96% (depends on the transmission stage) |
| Noise (max) | 60~ 68dB |
| Temp. rise (max) | 40°C |
| Temp. rise (oil) (max) | 5 0°C |
| Vibration | ≤20μm |
| Backlash | ≤20Arcmin |
| Brand of bearings | HRB/LYC/ZWZ/C&U (SKF, FAG, INA, NSK optional) |
| Brand of oil seal | NAK -- Taiwan or other brands requested |
Selected application examples:
- Car-washing and car-park systems
- Conveyors, mixers, agitators and hoists
- Agriculture and food processing
- Metal processing lines
- Textile, leather and paper industry
Support You Can Count On
WGT tests every SA57 speed reducer before shipment and supplies dimensional drawings, torque tables and maintenance guidance with each order. Batch buyers get framework pricing and reserved capacity; single orders ship the same production route with no minimum-order surcharge. One-year warranty included; inquiry replies within 24 hours, in English or Russian.
Selection Example: Assembly line lift
Take a 2.2 kW servo-ready motor at 1420 rpm on a lift axis needing 89 rpm. The ratio follows directly: 1420 / 89 = 16, i=16. In this case hollow output takes the lift screw directly - alignment is automatic. The same three numbers - motor speed, target output speed, required torque - are all you need; our engineers (or the online selector below) cross-check the service factor for your duty cycle.
![how to size a gear reducer in 4 steps - gearbox selection flow]()
Common Models in the SF Series
| Model | Centre distance | Output | Typical duty |
|---|
| SF37 | 37 mm | solid shaft, foot | small conveyors, dosing |
| SF47 | 47 mm | solid shaft, foot | packaging, dosing pumps |
| SF57 | 57 mm | solid shaft, foot | belt conveyors, stirrers |
| SF67 | 67 mm | solid shaft, foot | mixers, feeders |
| SF77 | 77 mm | solid shaft, foot | turntables, elevators |
| SF87 | 87 mm | solid shaft, foot | screw conveyors, washers |
| SF97 | 97 mm | solid shaft, foot | thickeners, kilns |
| SF107 | 107 mm | solid shaft, foot | heavy material handling |
The table below lists the eight foot-mounted frames;
Naming makes selection easy: S = solid shaft, SA = hollow shaft, SAF = hollow shaft with flange, SAZ = torque-arm version - all sharing the same gear set and centre distance as the SF foot model.
Application Cases
Grain handling station
A grain terminal powers its bucket elevators with SF77 gear reducers. The anti-run-back option holds the loaded buckets during power cuts, and standard interface dimensions meant the old foundations were reused as-is.
Quarry belt line
A stone quarry runs SF87 reducers on its primary conveyor. Shock loads from oversized rock are absorbed by the case-hardened gears (surface HRC58-62), and after two years of continuous duty the units run within their original 68 dB noise spec.
![industrial gearbox applications - conveyor mixer crusher wastewater]()
Frequently Asked Questions
What warranty and documentation come with the gearbox?
A one-year warranty covers material and workmanship. Each unit ships with a test record (noise, temperature rise, backlash), dimension drawing and installation manual.
What is the difference between SF, S, SA, SAF and SAZ versions?
They share one gear set: SF is foot-mounted with solid shaft, S is shaft-mounted, SA has a hollow output shaft, SAF adds a flange, and SAZ is the torque-arm version. Pick by mounting, not by performance.
Get Your Drawing and Quotation within 24 Hours
Stop guessing the ratio. Engineers can size the unit themselves in the WGT Motor & Gearbox Online Selection System - input speed, torque and duty, get the model instantly.
Or simply send your motor data (kW, speed, duty) and driven-machine details through the inquiry button - we reply with a completed datasheet, dimension drawing and factory price the same working day. Looking for a gearbox for packaging machine? Tell us the duty point and we will confirm the model in writing.
