SAI Hydraulics

Fixed displacement motors deliver consistent torque output and are used in applications requiring reliable, predictable performance.

• GM Series: Standard fixed displacement motors designed for high mechanical and volumetric efficiency, excellent cavitation resistance and precise speed control. Suitable for industrial and mobile circuits requiring reliability and stable performance.

• GS Series: High‑speed fixed displacement motors capable of rotational speeds up to three times higher than traditional radial piston motors. Ideal for high-power-density applications where speed and efficiency are critical.

• L Series: Fixed displacement motors used across a wide range of industrial and mobile applications, offering strong torque characteristics and robust construction.

• P Series: Compact fixed displacement motors designed for applications requiring high torque in a smaller footprint.

• TF Series: Seven‑cylinder fixed displacement motors designed for high continuous pressure ratings and demanding duty cycles.

• S Series: High‑speed fixed displacement motors offering a wide speed range and strong efficiency for dynamic applications.

Dual displacement motors allow switching between two displacement settings, providing flexibility for applications requiring both high torque and higher speed.

• BD Series: Five‑cylinder dual displacement motors offering displacement ratios from 1:2 to 1:4. Displacement can be changed while the motor is running, using hydraulic or electric control. Suitable for applications requiring both torque and speed flexibility.

• TD Series: Seven‑cylinder heavy‑duty dual‑displacement motors designed for high pressure, high flow and severe operating conditions. Ideal for drilling, winching and heavy industrial machinery.

Variable displacement motors provide continuous adjustment between maximum and minimum displacement, maintaining high efficiency even at very low displacement levels.

• BV Series: Five‑cylinder variable displacement motors with integrated electronic control. Suitable for circuits with wide operating ranges and demanding performance requirements.

• TV Series: Seven‑cylinder variable displacement motors offering extreme specific power, high sustainable pressure and continuous displacement variation down to 0 cc. Designed for the most severe and demanding applications.

Beyond hydraulic motors, SAI also manufactures:

• Wheel drive units with integrated planetary gearboxes and brakes

• Shaft‑end drive units for coupling motors to single or double stage gearboxes

• Brakes, valve blocks and flow dividers

• Custom distributor and shaft configurations for application‑specific requirements

These components support complete drive solutions for mobile and industrial machinery.

SAI motors use an eccentric crankshaft with cylinders that swivel to remain aligned with the crankshaft during rotation. This eliminates side loading between the piston and cylinder, reducing wear and improving efficiency. The design supports high torque output from standstill and stable operation at creep speed.

Each piston transmits load to the crankshaft through a hydrostatic bearing supported by a central roller bearing. This arrangement minimises metal‑to‑metal contact, reduces sliding velocity and improves lubrication. The result is lower friction, reduced heat generation and longer component life under high load.

Piston retaining rings ensure that each piston remains in contact with the crankshaft under all operating conditions, including cavitation or rapid load changes. This improves reliability and maintains smooth torque delivery across the motor’s full speed range.

SAI motors use an axial rotary distributor with short, large‑section oil paths to deliver hydraulic fluid to the pistons with minimal pressure loss. The distributor is available in multiple configurations, allowing motors to be tailored to specific applications, flow requirements and control strategies.

SAI’s variable and dual displacement motors provide flexible control of torque and speed:

• Variable displacement motors (BV and TV Series) allow continuous adjustment between maximum and minimum displacement, maintaining high efficiency even at very low displacement levels.

• Dual displacement motors (BD and TD Series) offer two selectable displacement settings, with the ability to switch while running using hydraulic or electric control.

These technologies support applications requiring both high torque at low speed and higher rotational speeds under lighter loads.

SAI’s GS and S Series motors are engineered for high rotational speeds, achieving speeds up to three times higher than traditional radial piston designs. This allows them to deliver power levels typically associated with axial piston motors while retaining the torque characteristics of a radial piston unit.

SAI also produces wheel drives, shaft‑end drive units, planetary gearboxes, brakes and valve blocks. These components can be combined with SAI motors to create complete drive solutions for mobile machinery, winches, drilling equipment and industrial systems.