NSK develops ball screw shift actuators for large outboard engines

Japan Seiko (NSK) has developed a small actuator with higher shifting operation for outboard engines. The use of high-efficiency automotive ball screws and high-output motors to increase shifting capacity and responsiveness while reducing size. The actuator has been used as a commercially available product on the outboard "F350" (manufactured by Yamaha Engine) with an output of 350 hp.
The original large ship was dominated by the inboard machine with the engine set in the ship, while the outboard machine has the advantages of convenient installation and maintenance, and can expand the space inside the ship. Therefore, the use of the outboard machine is increasing. In addition, when the mechanical shift is used, since the distance from the driver's seat to the outboard motor is far, it is necessary to connect with a long cable, and it is difficult to apply when there are many outboard engines and the number of seats is large. Affected by these shortcomings, more and more large-scale ships have begun to adopt wire-controlled design. Moreover, in the future of medium-sized vessels, wire-controlled design is also expected to be promoted. In order to cope with the trend of high power and wire control, Seiko has developed a high-power actuator that can work in harsh environments.
The actuator uses a Ball Screw with a conversion efficiency of 90%. By suppressing the energy loss of the actuator, high speed and high power are achieved, and even a high-power outboard motor can smoothly shift gears. Reliable and stable shifting is also achieved by producing thrusts that exceed human effort.
In addition, the direct installation on the engine is affected by high heat and vibration, so this time a high vibration-resistant motor and a non-contact position sensor are used. In addition, in order to prevent seawater from immersing while avoiding electromagnetic interference caused by sonar and wireless, the actuator metal casing also adopts a closed structure. It is also equipped with a water-resistant seal and a magnetic shield. Moreover, reliability is improved by using a dual sensor design.