ROTARY FLUID MACHINE

PROBLEM TO BE SOLVED: To suppress abrasion of each cylinder and abrasion of the part of each piston slidably contacting with each swing bush, in a rotary fluid machine with the piston slidably contacting with both the swing bush and cylinder. SOLUTION: In the cylinders 31, 41, an annular cylinder chamber is formed between inner cylinder portions 31c, 41c and outer cylinder portions 31b, 41b. The cylinder chamber is partitioned into the outer side and inner side of annular portions by the annular portions 32b, 42b of the pistons 32, 42. Each fluid chamber is partitioned into a high-pressure side and a low-pressure side by blades 33, 43. The swing bushes 34, 44 are provided between the annular portions and the blades. A piston side mirror plate portion has its outer peripheral portion slidably contacting with the outer cylinder portions. In the pistons, the hardness of sliding surfaces 62, 72 for the bushes slidably contacting with the swing bushes is higher than that of the cylinders sliding surface slidably contacting with the outer cylinder portions 31b, 41b. COPYRIGHT: (C)2011,JPO&INPIT