To provide a compact plunger mechanism for combining multiple thrust, reducing an overall length dimension and a radial dimension.

The plunger mechanism for combining multiple thrust includes a plurality of plunger elements which receive hydraulic pressure from a hydraulic system, generate hydraulic thrust and are connected to one output member so that the output member outputs resultant thrust in which the hydraulic thrust of the plurality of the plunger element groups is integrated. In the plunger mechanism, the output member is formed of a large-diameter piston 23 to which the plurality of plunger elements 26, 28 are connected, and a cylinder 29 movably storing the large-diameter piston 23. Plunger oil chambers 30, 32 for driving the plunger elements 26, 28 are formed on back sides of the plurality of plunger elements 26, 28, and the thrust of the output member is optionally selected by changing pressure oil to be supplied to the plunger oil chambers 30, 32.

COPYRIGHT: (C)2010,JPO&INPIT