Swash plate type hydraulic device

Claim 1

A swash plate type hydraulic device comprising a frame; a rotary shaft rotatably supported on said frame; a cylinder block mounted on said rotary shaft for rotation therewith, a plurality of cylinder bores being formed in said cylinder block and arranged in a circular pattern around the axis of rotation of said cylinder block; a plurality of plungers slidably fitted in said cylinder bores for reciprocating movement so as to define therein hydraulic chambers, said hydraulic chambers being selectively placed into communication with a low pressure hydraulic passage when said plunger is in a suction stroke and into communication with a high pressure hydraulic passage when said plunger is in an exhaust stroke; a swash plate mounted on said frame in an inclined manner with respect to said rotary shaft in opposing relation to said plungers; an annular shoe being in abutting engagement with said swash plate for relative rotation, said shoe having a slide surface opposed to said swash plate, said slide surface being formed with a plurality of hydraulic pockets in communication with said hydraulic chambers in said plungers via hydraulic passages; a plurality of connecting rods operatively connecting said shoe and said plungers, said hydraulic passages which communicate said hydraulic pockets with said hydraulic chambers being formed in and extending through said plungers, said connecting rods and said shoe; and a pair of synchronous gears respectively fixedly secured to said cylinder block and said shoe in meshing engagement with each other for synchronized rotation of said block and said shoe.