wherein said front face portions and said {HEAD ~ rear face portions} form {TAIL ~ inclined curved face portions} on both peripherial ends of said front and rear face portions to form hydrodynamic bearing face portions for multidirectional movements of said piston shoes, 
form
wherein said front face portions and said { HEAD ~ rear face portions } form { TAIL ~ inclined curved face portions } on both peripherial ends of said front and rear face portions to form hydrodynamic bearing face portions for multidirectional movements of said piston shoes ,
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH