Electro-Hydraulic Hybrid SystemKAWASAKI ECO SERVO

A Tiny System with the Power
to Drive Industrial Machines

Hydraulic equipment is popularly used for driving various industrial machines, as it provides intense power using a small driving force, thus delivering “high output density”. Previously, however, precise control on a par with electrically-driven equipment was impossible. To resolve this drawback and achieve a system that offers both the ease of control of electrically-powered equipment and the power of hydraulic products, Kawasaki developed an electro-hydraulic hybrid system, the KAWASAKI ECO SERVO.
　Unlike a conventional hydraulic pump, which is driven by a conventional motor and discharges a fixed amount of oil, ECO SERVO controls the variable-speed motor for the hydraulic pump in a precise manner and optimizes the volume of oil discharged according to the type of operation the industrial machine is performing.
　By better controlling the motor and employing a simplified hydraulic circuit, ECO SERVO achieves a 60 to 80% energy savings.
A reduction in the number of control valves on the circuit also makes the configuration much simpler, resulting in reduced heating Value and a more compact oil tank. The resulting ease of

maintenance is an additional benefit of the system. In some cases, needed installation space was reduced by two-thirds, and the volume of hydraulic oil used to one-twentieth that of conventional systems.
　ECO SERVO made its debut in 1999. Because the concept that motors could be controlled was totally new at that time, ECO SERVO was a revolutionary invention. Since then, the system has evolved and Kawasaki now offers a wide range of models, including a high-pressure, large-displacement type that achieves a continuous rated pressure of 32 MPa and a maximum pump displacement of 500 cm3.
　ECO SERVO is being utilized with a diverse range of industrial equipment, such as large press machines and injection molding machines. Not only that, but it is also being used in applications closer to our everyday lives, such as adjustment systems for variable pitch blades of ventilators installed in highway tunnels and for laundry dewatering presses.

01Variable displacement
pump

Displacement produced by the pump is switchable (large/small).
By reducing the displacement during the high-pressure state, the torque can be lowered, which allows the capacity of the motor to be minimized.

02Suction valve plate

A highly-efficient suction valve plate that accommodates both clockwise and counterclockwise rotations significantly improves pressure pulsation at low speed rotation during pressure control. It thus offers improved performance and reduced noise.

03Suction valve

For closed-circuit configurations, ECO SERVO is equipped with a suction valve with superior self-priming capability, designed to compensate for the shortage of the flow. This function is unique to Kawasaki’s system.

Combining the best of
hydraulic and electrical systems

ECO SERVO is a hydraulic hybrid system that renders high-density power along with the precise controllability of an electrically-driven system. In a conventional hydraulic system, the motor is constantly running and consuming power even when the machine is not in operation. ECO SERVO, on the other hand, controls the motor speed and drives the pumps only when they are needed, achieving a dramatic reduction in power consumption, which in some cases goes as high as 80%.