Piston assembly and fluid pressure device

A fluid pressure device, comprising:

• a body having a sliding hole inside the body;
• and
• a piston assembly disposed to be able to reciprocate along the sliding hole, wherein:
• the piston assembly includes a piston body displaceable in an axial direction inside the sliding hole and a piston rod protruding from the piston body in the axial direction;
• the piston body includes a piston-side engaging portion;
• the piston rod includes a rod-side engaging portion engaging with the piston-side engaging portion;
• one of the piston-side engaging portion and the rod-side engaging portion is inserted into the other from a side to engage with each other to regulate relative axial displacement between the piston body and the piston rod:
• the piston body includes a disk-shaped wall portion and the piston-side engaging portion which protrudes in the axial direction of the piston body from the disk-shaped wall portion;
• the piston-side engaging portion includes an engaging groove which has a U shape, a C shape, or a semicircular arc shape and an inner protrusion which protrudes inward and is disposed adjacent to the engaging groove, the engaging groove being formed between the disk-shaped wall portion and the inner protrusion;
• the rod-side engaging portion includes an engaging protrusion having an annular shape and an annular groove which is disposed adjacent to the engaging protrusion and extends in a circumferential direction of the piston rod;
• the inner protrusion of the piston-side engaging portion is fitted in the annular groove of the rod-side engaging portion;
• and
• the engaging protrusion of the rod-side engaging portion is fitted in the engaging groove of the piston-side engaging portion,
• wherein:
• a damper mechanism configured to relieve impact occurring when the piston body reaches at least one of stroke ends;
• the damper mechanism is supported by the piston body so as not to transmit impact load to the piston body when the piston body reaches the stroke end;
• the damper mechanism includes a circumference-side damper disposed around an outer circumferential part of the piston rod;
• the piston rod is provided with a stopper receiving groove extending in a circumferential direction in the outer circumferential part;
• a stopper member divided into a plurality of elements in the circumferential direction is fitted in the stopper receiving groove;
• and
• the circumference-side damper covers the stopper member, and thus the stopper member supports the circumference-side damper and is prevented from coming off the stopper receiving groove.