Description
KA Series — Hollow Shaft Worm Gear Reducer
The KA Series is a foot-mounted, hollow-shaft worm gear reducer designed for direct shaft-mounting onto screw conveyors, agitator shafts, and roller drives. Unlike the motor-flange DKA variant, the KA uses a bare input shaft that accepts a V-belt pulley, chain sprocket, or flexible coupling, giving engineers the freedom to position the motor away from the reducer or add an intermediate speed stage. Thirteen frame sizes from WP40 to WP250 cover ratios of 5:1 through 60:1 and output torques up to 3,025 N·m. The keyed hollow bore slides directly over the driven machine shaft and is held by a torque-arm bracket, eliminating the rigid coupling, pillow-block bearing, and alignment procedure that a solid-shaft reducer would require.
Practical Applications
Screw Conveyors and Auger Feeders
The KA is the workhorse reducer on screw-conveyor head drives in cement, grain, and recycling facilities. The hollow bore slides over the conveyor head shaft, the torque arm bolts to the trough frame, and the motor drives the KA input through a V-belt. This belt-driven arrangement gives operators a convenient way to fine-tune the conveyor speed by changing pulley diameters, without ordering a different gear ratio. Equipment built by Martin Engineering, WAM, and Continental Screw frequently pairs with the KA in the WP100–WP175 range.
Tank Agitators and Paddle Mixers
Food-processing tanks, chemical reactors, and wastewater flocculators use the KA to mount directly on the horizontal mixer shaft. At ratios of 20:1 to 40:1, the self-locking worm gearbox property holds the impeller stationary during loading and discharge, and the hollow bore lets maintenance crews slide the reducer off the shaft for cleaning or bearing inspection without disturbing the agitator itself.
Foot-mount, hollow bore, and torque-arm positions
Technical Specifications
All torque values below apply at 1,500 r/min input. The KA shares the same WP-platform gear geometry, bearings, and alloy as every other single-stage model in the speed reducer gearbox range. Hollow-bore diameters listed are standard production sizes.
| Frame (mm) | Ratios | Torque at 10:1 (N·m) | Peak Torque (N·m) | Hollow Bore (mm) |
|---|---|---|---|---|
| WP40 | 5:1 – 60:1 | 6 | 20 | 14 |
| WP60 | 5:1 – 60:1 | 19 | 73 | 20 |
| WP80 | 5:1 – 60:1 | 77 | 248 | 28 |
| WP100 | 5:1 – 60:1 | 80 | 344 | 32 |
| WP120 | 5:1 – 60:1 | 151 | 521 | 40 |
| WP155 | 5:1 – 60:1 | 270 | 1,260 | 55 |
| WP200 | 10:1 – 60:1 | 623 | 2,856 | 70 |
| WP250 | 10:1 – 60:1 | 850 | 3,025 | 85 |
Construction and Materials
The KA housing is a one-piece grey cast-iron casting with machined foot pads on two perpendicular planes for horizontal or vertical mounting. The output bore is machined to H7 tolerance and fitted with a standard parallel keyway. The input side is a solid shaft with keyway, supported on tapered roller bearings, protruding from the housing for belt-pulley or coupling attachment. The worm shaft is case-hardened 20CrMnTi alloy steel, thread-ground to a surface finish better than Ra 0.8 μm. The worm wheel is centrifugally cast ZCuSn10Pb1 tin-bronze. Oil seals on every shaft penetration are double-lipped NBR with a dust-exclusion outer lip. A sight glass and breather plug are standard on all frames.
Components and Spare Parts
Every wear component inside this reducer is available as an individual spare part, allowing targeted replacement rather than full-unit swap. Our Condell Park, NSW warehouse stocks parts for the complete range and ships across Australia and New Zealand. The KA draws from the same parts catalogue as the DA, DKA, DS, and DKS models. A WP120 worm wheel, for example, fits any single-stage WP120 housing regardless of the shaft or mounting configuration.
Worm Shaft
Case-hardened 20CrMnTi alloy steel, thread-ground to Ra 0.8 μm finish
Worm Wheel
Centrifugally cast ZCuSn10Pb1 tin-bronze, hobbed full-depth involute profile
Bearings
Tapered roller bearings handling combined radial and axial loads on both shafts
Seal & Gasket Kit
Double-lipped NBR oil seals, housing gaskets, breather plugs, and O-rings
Worm shaft, bronze wheel, bearings, and seal kits — all orderable separately
Oil and Maintenance
Use ISO VG 220–320 EP gear oil for temperatures up to 40 °C. Shell Omala S2 G 220 and Mobil DTE Oil BB are recommended. Change the factory oil after the first 100 hours, then every 2,500 hours or annually. Inspect the torque-arm fasteners at every oil change to verify vibration has not loosened them. Check the input-shaft bearing for radial play annually — belt tension places a continuous side load on this bearing, so it may wear faster than in motor-flange models.
Customer Reviews
The KA hollow bore slid right over our screw-conveyor shaft. No coupling, no alignment headache. We paired it with a belt drive from the motor and the whole thing was running within two hours of delivery.
Greg Foster
Conveyor Engineer, Mining Services
We mount the KA on our CIP tank agitator shafts. The torque arm keeps it locked in position and the hollow bore lets us slide the reducer off for cleaning without unbolting the agitator shaft. Very practical.
Anna Leigh
Process Engineer, Dairy Plant
Ordered replacement worm wheels for three KA units. Parts arrived in four days and the swap took about 90 minutes per gearbox. Good value versus buying new units.
Tony Marcello
Workshop Manager, Quarry Operations
Source from Ever-Power Australia
Ever-Power Transmission Australia Pty Ltd stocks KA frame sizes alongside the full WP range at our Condell Park, NSW facility. We also supply PGV planetary gearbox for servo-driven positioning applications. contact us or call +61 2 9708 3322 for sizing, pricing, and lead times.
ISO 9001-certified manufacturing and testing
