Conveyor, agitator and bucket-elevator builders keep standardising on the SF57 speed reducer gearbox because it combines a high reduction ratio with a right-angle output in very little space. The helical input stage absorbs motor speed down to an intermediate level, and the worm stage finishes the job - so the machine sees smooth torque without the gear whine typical of all-helical drives at similar ratios.
Why the SF57 Fits Conveyor Duty
- Foot and torque-arm mountings; shaft or hollow-bore output for direct chain coupling
- Efficiency 94%~96%, temperature rise max 40 °C even in 12-hour continuous duty
- Standard interface dimensions - no need to modify existing brackets or guards
- Optional anti-run-back device for inclined conveyors
- Oil seals by NAK (Taiwan) as standard; FKM seals available for hot or wash-down areas
Specification Table
| 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 |
Proven in service across these industries:
- Conveyors, mixers, agitators and hoists
- Building and construction machinery
- Agriculture and food processing
- Wood, forest and recycling equipment
- Car-washing and car-park systems
Quality Assurance
Each SF57 gear reducer leaves the plant after a no-load run-in test with noise and vibration logging. Gears are ground on Reishauer-class machines; housings are machined on a single machining centre so bores stay concentric. A one-year warranty covers material and workmanship. Ask for the dimensional drawing or a completed datasheet with your ratio and duty cycle - we normally reply the same working day.
Application Cases
Automatic car-wash system
A car-wash equipment builder fits SA57 hollow-shaft reducers to its conveyor chains. The compact frame hides inside the wash tunnel, and FKM seal options handle the constant moisture.
Dust-extraction fan bank
An environmental-equipment plant uses SF47 reducers on rotary valve feeders of its dust-extraction systems. Compact size, quiet running and food-grade oil options made the approval easy.
![industrial gearbox applications - conveyor mixer crusher wastewater]()
Selection Example: Bagging belt conveyor
Take a 3 kW, 1440 rpm motor on a bagging belt requiring roughly 36 rpm. The ratio follows directly: 1440 / 36 = 40, i=40 selected. In this case torque-arm mounting absorbs belt pull without extra bearings. 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.
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 mixer and agitator? Tell us the duty point and we will confirm the model in writing.
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.
