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