| Definition | A compact hydraulic motor, commonly combined with a planetary reduction gearbox, that drives the tracks or wheels of mobile equipment. | It converts hydraulic flow and pressure into controlled travel torque and speed. |
| Typical Applications | Mini excavators, compact loaders, tracked carriers, small drilling machines, agricultural machines, and access equipment. | These machines require high starting torque, low-speed control, and a compact drive package. |
| Typical Motor Displacement | Approximately 10–80 cm³/rev for many compact-equipment applications. | Lower displacement generally supports higher speed at a given flow; higher displacement generally provides more torque at the same pressure. |
| Typical Working Pressure | Approximately 160–280 bar, depending on the motor design and machine hydraulic circuit. | Higher pressure capability allows strong tractive effort without requiring a large motor displacement. |
| Typical Peak Pressure | Approximately 210–350 bar for short-duration load peaks on suitable designs. | Peak-pressure ratings must not be treated as continuous operating ratings; relief-valve settings and duty cycles are important. |
| Typical Flow Range | Approximately 15–80 L/min per motor for compact machines. | Flow determines motor speed. The hydraulic system must provide sufficient flow without exceeding the motor’s continuous rating. |
| Typical Output Speed | Approximately 20–150 rpm at the gearbox output, depending on displacement, flow, and reduction ratio. | Low output speed provides controlled movement and helps the machine start smoothly on uneven ground. |
| Typical Continuous Output Torque | Approximately 500–4,000 N·m at the final-drive output for many compact tracked machines. | Output torque is increased by the reduction gearbox and is used to overcome rolling resistance, slopes, and ground conditions. |
| Torque Relationship | Motor torque is approximately proportional to pressure difference × displacement × mechanical efficiency. | For example, increasing pressure or displacement can increase torque, but heat generation, structure, and system limits must also be considered. |
| Speed Relationship | Motor speed is approximately proportional to hydraulic flow ÷ displacement. | A variable-displacement design can help provide both high travel speed on level ground and higher torque when climbing or turning. |
| Gear Reduction | Commonly a multi-stage planetary reduction system, often with an approximate ratio of 10:1–50:1. | The gearbox reduces rotational speed and multiplies torque while keeping the drive unit compact. |
| Installation Space | Designed for limited-width and limited-height mounting areas inside or beside a track frame or wheel hub. | A small housing can preserve ground clearance and make integration easier in compact equipment. |
| Weight Consideration | Commonly lighter than a larger drive unit designed for the same machine class, although actual weight varies with torque rating and gearbox ratio. | Lower drive weight can help maintain payload, balance, transportability, and overall machine efficiency. |
| Travel Control | Supports low-speed operation, directional reversal, and differential track control when used with suitable valves and controls. | Precise hydraulic control improves maneuverability in confined work areas. |
| Protection Features | Typical features may include an integrated parking brake, pressure relief protection, anti-cavitation protection, and mechanical seals. | These features help protect the drive during parking, sudden load changes, downhill travel, and contaminated working conditions. |
| Efficiency Factors | Overall efficiency depends on motor type, displacement, pressure, speed, gearbox losses, oil temperature, and seal condition. | Correct sizing helps reduce heat, hydraulic power losses, and unnecessary fuel or battery consumption. |
| Selection Criteria | Required tractive force, machine weight, maximum slope, travel speed, hydraulic flow, working pressure, mounting dimensions, and duty cycle. | Choosing by physical size alone can cause insufficient torque, overheating, excessive speed, or premature component wear. |
| Main Advantages | Compact packaging, high starting torque, smooth low-speed movement, direct hydraulic control, and compatibility with tracked or wheeled layouts. | These advantages make small travel motors suitable for machines that work in narrow spaces and frequently change direction. |