An Inside Story of Invention of HySerpack

第一電気株式会社　佐藤　寛

Mr. Hiroshi Sato, then a 55-year old electrical engineer, witnessed the crash of JAL123 into a mountain in the central area of Japan.   It was a hot and humid day in August 1985.  The lives of 520 people were lost.  It was reported that the crash was caused by the failure of hydraulic systems.   All four lines including back-up lines of the hydraulic pipes which regulated the rudder on a vertical fin were destroyed during the flight due to the collapse of the pressure wall at the rear end of the airplane.  The total loss of hydraulics resulted in the loss of control over the airplane and the crash. 

A very similar accident happened to the United Air Lines DC-10 Flight 232 on July 19, 1989 at Sioux City when an engine exploded and caused the total loss of hydraulics.　

In 1985 soon after the JAL accident, Sato determined to develop an electro-driven hydraulic actuator which has no valve nor pipe on itself and can operate by electrical signals under as severe conditions as conventional hydraulic systems on airplanes function.  He had an idea of what design it had to be and what materials and parts had to be used, etc.  But it took 10 years for him to complete the development of the unit which satisfies his high level of desire and standard.  The developed unit is named Hybrid Actuator “HySerpack”.

Sato’s challenges to the conventional thoughts and designs of hydraulic systems have continued even after the completion of development.  He has been improving the control software of HySerpack so it can be used for a wider range of applications from presses to injection mold machines to ocean vessels to super bullet trains, to name just a few.