cameroon gce A level mechanical design 3
cameroon gce A level mechanical design 3
THEME: MICRO-BLOCK
I. PRESENTATION
The micro-block (reducer) represented on page 5 is used in handling devices and also when they need:
– a high approach velocity and a small displacement around the working zone.
– a small working speed of work and a high return speed
The user has the choice of the ratios of reduction of the two planetary gears and the screw/wheel couple. Different values are proposed to the designer.
II. FUNCTIONING
1- High velocity
The belt 25 of the reducer of the epicyclical train is maintained fixed in rotation by the intermediary of the screw/wheel couple 34/13, the screw 34 being held fixed by the engine brake LV (Low velocity).
2- Low velocity
The pinion 19 is maintained fixed in rotation by the brake of the engine HV (High velocity). The belt 25 is pulled in rotation by the intermediary of the wheel 13, of the screw 34 and of the engine LV.
3- Conjugated high speed
The two engines HV and LV turn at the same time with a velocity of 1500 tr/mn. It is known that the shaft 1 turns with a velocity equal to the sum of the HV and LV. The two velocities used are normally the low velocity and the conjugated high velocity.
Characteristics of the gears
