Conveyor, mixer and pump builders keep standardising on the R47 coaxial gear reducer because it delivers a wide reduction range in a housing that stays on the machine axis. Nothing protrudes sideways, so the drive can be tucked under a deck, inside a frame or against a wall - layouts where a right-angle gearbox would foul the structure.
Built Around a 47 mm Centre Distance
- Foot mounting as standard; flanged and shaft-mounted variants share the same gear set
- Case-hardened 20CrMnTi gearing, ground to grade 6~5; noise held between 60 and 68 dB
- Cast-iron / ductile-iron housing at HBS190-240 - stable under impact and vibration
- Standard interface dimensions, so brackets, couplings and guards do not have to change
- NAK oil seals as standard; FKM seals available for hot or wash-down areas
Technical Specification
| 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, carburising, quenching, etc. |
| Efficiency | 94%~96% (depends on the transmission stage) |
| Noise (max) | 60~68 dB |
| Temp. rise (max) | 40 C |
| Temp. rise (oil) (max) | 50 C |
| Vibration | ≤20 µm |
| 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:
- Belt, screw and chain conveyors
- Cranes, hoists and winches
- Pumps, fans and blowers
- Mining and bulk material handling
- Mixers, agitators and kneaders
Support and Documentation
WGT ships every R47 with a dimension drawing, a rating table and a test sheet. The R frame can be specified for foot, flange or shaft mounting; the gearing, ratio and centre distance are identical across the variants, so only the output interface changes. Tell us the driven machine, the output speed and the daily running hours, and we confirm the model and quote in writing.
Field Applications
Grain terminal elevators
A grain terminal powers its bucket elevators with 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 they were.
Pallet lift in a warehouse
A logistics integrator selected units for pallet lifts. The hollow output bore carries the lift screw directly, and one year of three-shift operation has passed without a single seal replacement.
![where gear reducers are used in industry]()
Where these units are installed across industry.
Selection Example: Fish-farm aerator blower
Take a 5.5 kW motor at 2900 rpm turning the blower at 145 rpm. The ratio follows directly: 2900 / 145 = 20, so i=20 with margin. In this case 94~96% efficiency keeps the running cost of continuous aeration low. Once the ratio is fixed, check the required output torque against the rating table with the service factor applied - that is what decides the frame, not the ratio alone.
![gearbox selection guide: speed, torque, service factor]()
How a ratio and a frame size are determined, step by step.
Frame Sizes and Typical Duties
| Model | Centre distance | Output | Typical duty |
|---|
| R47 | 47 mm | solid shaft, foot | screw conveyors, feeders |
| R17 | 17 mm | solid shaft, foot | small conveyors, dosing screws |
| R27 | 27 mm | solid shaft, foot | packaging, light agitators |
| R37 | 37 mm | solid shaft, foot | belt conveyors, small mixers |
| R57 | 57 mm | solid shaft, foot | mixers, aeration blowers |
| R67 | 67 mm | solid shaft, foot | mixers, extruders |
| R77 | 77 mm | solid shaft, foot | extruders, heavy conveyors |
| R87 | 87 mm | solid shaft, foot | screw conveyors, agitators |
| R97 | 97 mm | solid shaft, foot | thickeners, blowers |
| R107 | 107 mm | solid shaft, foot | aerators, heavy conveyors |
| R137 | 137 mm | solid shaft, foot | mill drives, large hoists |
| R147 | 147 mm | solid shaft, foot | mill drives, heavy hoists |
| R167 | 167 mm | solid shaft, foot | heaviest inline drives |
Read the frame number as the centre distance in millimetres, from 17 mm up to 167 mm. Gearing, efficiency and backlash are unchanged across the range; only torque capacity and shaft size step up with the frame.
From Duty Point to Delivery in One Working Day
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.
Tell us what the machine does and how hard it works; we calculate the ratio, apply the service factor and send back the drawing and quotation within one working day, including sea-freight and air-freight options. Looking for a gearbox for mixer and agitator? Tell us the duty point and we will confirm the model in writing.
Common Questions from Buyers
What ambient temperature range can the unit work in?
Standard units suit -10 to +40 deg C ambient with the supplied mineral oil. For lower temperatures we fill with synthetic oil; for higher ambient or frequent starting we advise the next larger frame or an oil cooler.
What are the delivery lead times and shipping terms?
Standard lead time is 5-10 weeks ex-works, with popular ratios often available sooner. We quote EXW, FOB NINGBO / SHANGHAI or CIF, and urgent units can be air-freighted within 72 hours of payment.
What materials are used for the gears and shafts?
Gears are 20CrMnTi alloy steel, case-carburised to HRC58-62 over a tough HRC33-40 core. Input and output shafts are 42CrMo, quenched and tempered to HRC25-30. The housing is cast iron at HBS190-240.
