Swash plate type variable displacement hydraulic rotary machine

A swash plate type variable displacement hydraulic rotary machine comprising a tubular casing having at one end a swash plate support portion and at the other end a pair of supply/discharge passages, a rotational shaft rotatably supported in said casing, a cylinder block provided in said casing for rotation together with said rotational shaft and containing a plural number of axially extending cylinders in circumferentially spaced positions, a plural number of pistons reciprocally fitted in said cylinders of said cylinder block, a plural number of shoes attached to projected ends of said pistons projected from said respective cylinders, a swash plate having on a front side a smooth surface for guiding said shoes by sliding contact therewith and on a rear side a pair of leg portions tiltably supported by said swash plate support portion, a tilting actuator provided within said casing to drive said swash plate into a tilted position according to a tilting control pressure which is supplied to and from outside, hydrostatic bearings provided between said leg portions of said swash plate and said swash plate support portion in communication with said supply/discharge passages to keep contacting surfaces of said leg portions and said swash plate support portion in a lubricated state, characterized in that said hydrostatic bearings comprises:

• said hydrostatic bearing constituted by a first main hydrostatic bearing provided on one leg portion of said pair of leg portions, a second main hydrostatic bearing provided on the other leg portion, a first auxiliary hydrostatic bearing provided on said other leg portion at a position spaced from said second main hydrostatic bearing, and a second auxiliary hydrostatic bearing provided on said one leg portion at a position spaced from said first main hydrostatic bearing;
• and
• said first and second slide bearings are provided on said pair of leg portions more radially distant from said rotational shaft than said first and second main hydrostatic bearings and said first and second auxiliary hydrostatic bearings.