单项选择题
A.telescopic pipe B.large bore pipe C.generating pipe D.central pipe
Because of the high loads the bearing material is a tin...
单项选择题Because of the high loads the bearing material is a tin- aluminum alloy bonded to a steel shellThe crosshead pin is highly polished to a （）.
A.flat surface B.mirror finish C.sloping surface D.inclined surface
The load on the crosshead pin is always （）, so it is th...
单项选择题The load on the crosshead pin is always （）, so it is the （）half of the bearing which is subject to wear.
A.upwards；top B.upwards；bottom C.downwards；top D.downwards；bottom
Because the top of the connecting rod swings about the ...
单项选择题Because the top of the connecting rod swings about the pin and changes direction each time the piston reaches mid-stroke, the relative speed between bearing and pin at mid-stroke is zero, （）to a maximum as the piston approaches top or bottom dead center and then （） back to zero again as the piston approaches mid-stroke and the connecting rod changes direction.
A.accelerates；decelerates B.accelerates；accelerates C.decelerates；decelerates D.decelerates；accelerates
