KM20/KM30/KM35/KM40 KAPPA Series Cast Iron Gear Motors
The KM series is the gear motor version corresponding to the KP gear pumps (KAPPA motors). It adopts a two-piece cast iron housing external gear motor. Sharing the same structure as KP pumps, each frame size maintains nearly identical mounting dimensions, flanges and port connections. Pressurized hydraulic fluid generates rotary torque. Available as single motors or multi-combined motors, widely used for heavy-duty drive in mobile construction machinery.
✅ Core Features
- Two-piece GG300 cast iron housing with high rigidity, excellent vibration and shock resistance for harsh working conditions, outperforming aluminum alloy motors.
- High pressure and high torque output. Peak pressure up to 330 bar with stable torque. Equipped with external sliding bearings to withstand high radial loads.
- Bi-directional rotation for forward and reverse drive. Internal drain and separate external drain versions are optional.
- Low pulsation and low noise. Precisely manufactured hardened gear pairs deliver high volumetric efficiency with minor performance degradation at elevated temperatures.
- Modular design: Integrated valves (relief valves, makeup valves, anti-cavitation valves) are available. Multi-combined motor assemblies are supported. SAE / European flanges and a variety of splined or plain shafts can be selected.
- Seal options: Standard NBR seals; FKM fluororubber seals for high temperature and biodegradable hydraulic oil applications.
📊 KM20/KM30/KM35/KM40 Overall Parameters
| Series | Theoretical Displacement cm³/rev | Continuous Working Pressure bar | Peak Pressure bar | Max Speed rpm |
|---|---|---|---|---|
| KM20 | 4.95～25.0 | Up to 280 | Up to 330 | 4000 |
| KM30 | 17.28～73.82 | 170～280 | Up to 325 | 3000 (2500 for large displacement versions) |
| KM35 (KAPPA Compact) | 63.88～91.56 | 245～260 | Up to 275 | 3000 |
| KM40 / KM40 Plus | 61.43～180.73 | 200～260 | Up to 330 | 2800 (lower for large displacement models) |
Minimum stable speed: approx. 350 rpm; Recommended fluid: ISO VG32/VG46 hydraulic oil; Oil temperature: -20 ~ +80℃
Motor note: Limited allowable back pressure. Reversible motors require attention to drain port pressure limits.
🔹 KM20 Common Models
| Model | Displacement cm³/r | Continuous Pressure bar | Peak Pressure bar | Max Speed rpm |
|---|---|---|---|---|
| KM20.5 | 4.95 | 280 | 330 | 4000 |
| KM20.6.3 | 6.61 | 285 | 330 | 4000 |
| KM20.8 | 8.26 | 285 | 330 | 3500 |
| KM20.11.2 | 11.23 | 275 | 320 | 3500 |
| KM20.14 | 14.53 | 265 | 320 | 3500 |
| KM20.16 | 16.85 | 260 | 320 | 3000 |
| KM20.20 | 20.30 | 250 | 310 | 3000 |
| KM20.25 | 25.00 | 240 | 300 | 3000 |
🔹 KM30 Common Models
| Model | Displacement cm³/r | Continuous Pressure bar | Peak Pressure bar | Max Speed rpm |
|---|---|---|---|---|
| KM30.27 | 26.70 | 280 | 310 | 3000 |
| KM30.34 | 34.56 | 260 | 300 | 3000 |
| KM30.38 | 39.27 | 260 | 300 | 3000 |
| KM30.43 | 43.98 | 250 | 290 | 3000 |
| KM30.51 | 51.83 | 230 | 270 | 2500 |
| KM30.56 | 56.54 | 215 | 255 | 2500 |
| KM30.61 | 61.26 | 200 | 240 | 2500 |
| KM30.73 | 73.82 | 170 | 220 | 2500 |
🔹 KM35 (Compact) Common Models
| Model | Displacement cm³/r | Continuous Pressure bar | Peak Pressure bar | Max Speed rpm |
|---|---|---|---|---|
| KM35.63 | 63.88 | 260 | 275 | 3000 |
| KM35.71 | 72.40 | 260 | 275 | 3000 |
| KM35.80 | 80.91 | 260 | 275 | 3000 |
| KM35.90 | 91.56 | 245 | 270 | 2500 |
🔹 KM40 / KM40 Plus Common Models
| Model | Displacement cm³/r | Continuous Pressure bar | Peak Pressure bar | Max Speed rpm |
|---|---|---|---|---|
| KM40.63 | 61.43 | 260 | 325 | 2800 |
| KM40.73 | 72.60 | 260 | 325 | 2800 |
| KM40.87 | 86.56 | 240 | 305 | 2800 |
| KM40.109 | 108.90 | 220 | 275 | 2800 |
| KM40.140 | 140.50 | 210 | 270 | 2500 |
| KM40.180 | 180.73 | 200 | 260 | 2200 |
🛠️ Structural & Selection Key Points
- Construction: Two-piece cast iron housing, carburized and hardened gears, nitrided ductile iron side plates, external sliding bearings with strong radial load resistance.
- Drainage type: Internal drain or separate external drain (widely used for bi-directional motors to protect shaft seals).
- Output shaft: Plain key or SAE spline available; Mounting flange: SAE / European 4-bolt flange.
- Optional integrated valves: Relief valve, makeup valve and anti-cavitation valve to protect the motor and simplify hydraulic circuits.
- Model naming example:
KM30.34-A8K9- KM = KAPPA Gear Motor; 30 = frame size; 34 = displacement; suffix defines shaft, flange, drain type, rotation, seal and other configurations.
📌 Typical Applications
- Construction machinery: Fan drive, conveyor mechanism and auxiliary slewing drive for skid steer loaders, forklifts, mini excavators and aerial work platforms.
- Sanitation vehicles: Sweeper disc motors, conveyor motors and fan drives.
- Agricultural machinery: Harvester conveyors, augers and auxiliary travel drive.
- Special vehicles: Truck-mounted crane winches, small slewing mechanisms and belt conveyor equipment.
- Industrial hydraulics: Material transport rollers and small winch assemblies.
