Patent ID: 7546733
Filing Date: 2009-06-16
Classification: F15B,Y10T

Abstract:
1. A method for controlling operation of a cylinder apparatus comprising a piston which is provided displaceably in a cylinder body, a ball screw which is engaged with said piston, and a driving section which drives and rotates said ball screw, wherein said piston is displaced by a driving force of said driving section and a pressure of a pressure fluid supplied to a cylinder chamber of said cylinder body to move a workpiece attached to said piston, said method comprising the steps of: applying a weight load to said piston, said weight load applied to said piston fluctuating during a displacement range of said piston; displacing said piston along said cylinder body by said ball screw under a driving action of said driving section; supplying the pressure fluid to said cylinder chamber at a pressure corresponding to fluctuation of said weight load before said weight load applied to said piston is fluctuated so that a pressing force, which is substantially balanced with said weight load, is applied to said piston; and moving said piston by said driving force brought about by said driving section and said pressing force brought about by said pressure fluid.