When a drive needs more muscle than the small K frames can give, the K87 helical bevel gearbox steps in: 87 mm centre distance, robust 42CrMo shafts and a housing section designed for continuous load. The unit follows the standard interface dimensions of the K87 frame family and is widely used on screw conveyors, industrial washers, mixing plant and sawmill equipment.
Built for Continuous Duty
Toothed gearing on both stages keeps losses low and heat generation modest, which is what allows the K87 to run long shifts without an oil cooler. Surface hardness reaches HRC58~62 over a ductile HRC33~40 core; the maximum temperature rise is 40 °C on the housing and 50 °C on the oil, both verified in factory run-in tests.
- Foot, flange or hollow-shaft mounting; solid or hollow output in the same frame
- Premium bearing brands - HRB, LYC, ZWZ or C&U, with SKF, FAG, INA or NSK on request
- NAK oil seals as standard; FKM for hot or wash-down duty
- Lubricated for life under normal duty with GB L-CKC220~460 or Shell Omala 220~460
Complete 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, 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 |
Duties this frame size is regularly chosen for:
- Coal mining and bulk material handling
- Cement and construction machinery
- Conveyors, mixers, agitators and crushers
- Hoist and transport equipment
- Paper and light industry
How to Order the K87
Specify ratio, output speed, mounting position (M1-M6) and shaft direction; WGT returns a selection confirmation with torque limits and a firm price. Sampling units for OEM validation are welcome. Production lead time is normally 5-10 weeks with sea or air freight from NINGBO / SHANGHAI, and all K87 gear reducers carry a one-year warranty and lifetime technical support.
Selection Example: Belt conveyor on a quarry screen
Take a 7.5 kW, 1440 rpm motor driving a conveyor at 24 rpm. The ratio follows directly: 1440 / 24 = 60, so i=60. In this case the 87 mm frame absorbs the shock of irregular stone feed. Work through the same three steps - speed, output speed, torque - and the model number falls out; we verify it against the duty class before quoting.
![gear reducer ratio calculation steps]()
From duty point to model number - the same four steps every time.
Applications in Industry
Mining slurry pump drive
At a mineral processing site, hollow-shaft reducers drive slurry pump agitators. The hollow bore takes the pump shaft with no coupling, so a pump change-out no longer means re-aligning a separate drive.
Palm oil mill fruit elevator
A palm oil mill powers its fruit elevator with reducers. The humid, oily atmosphere is handled by FKM seals, and the compact frame fits between the steriliser and the threshing drum.
![gear reducer industries served - WGT]()
Industry map: the sectors where the K series is most common.
Buyer Questions and Answers
What paint finish and corrosion protection is applied?
Housings are shot-blasted and finished with a two-component industrial paint in RAL colours, giving good protection for indoor and sheltered outdoor duty. For aggressive or coastal sites, ask for the heavy-duty coating option.
Do you supply spare parts such as seals and bearings?
Seal kits, bearings, output shafts and covers are available from stock or on short lead time. We keep the drawings for every unit we ship, so a replacement part ten years from now is still traceable to your original order.
K Series Model Overview
| Model | Centre distance | Output | Typical duty |
|---|
| K87 | 87 mm | solid shaft, foot | screw conveyors, washers |
| K37 | 37 mm | solid shaft, foot | small conveyors, hoists |
| K47 | 47 mm | solid shaft, foot | packaging, agitators |
| K57 | 57 mm | solid shaft, foot | belt conveyors, mixers |
| K67 | 67 mm | solid shaft, foot | mixers, feeders, hoists |
| K77 | 77 mm | solid shaft, foot | turntables, elevators |
| K97 | 97 mm | solid shaft, foot | thickeners, heavy conveyors |
| K107 | 107 mm | solid shaft, foot | heavy material handling |
| K157 | 157 mm | solid shaft, foot | mill drives, large hoists |
| K167 | 167 mm | solid shaft, foot | heaviest right-angle drives |
The series is sized by centre distance rather than by motor power, so one frame can serve several motor sizes and ratios. The K / KA / KF / KAF suffixes describe shaft and mounting, not capacity.
Fast Quotation for OEM and Repeat Orders
Buying one unit or one hundred? Run your duty point through the WGT Motor & Gearbox Online Selection System first: it saves a round of emails and gets you to a firm price faster.
Single units ship on the same production route as batch orders, with no minimum-order surcharge. For OEM programmes we hold framework pricing and reserve capacity for your scheduled call-offs. Looking for a gear reducer for food processing machine? Tell us the duty point and we will confirm the model in writing.
