Today we talk about different mechanical motion mechanism of motor selection of some of the calculation method and formula of calculation time.
the first reducer, of course, this is very common.
the second that must be a belt and chain gear reducer, the teacher also often speak. This in some factories back label is often used in the design requirements.
the third, gear box.
guide screw
convert to the motor torque: according to the law of conservation of energy: if we take into account the screw, the load, the workbench's data and efficiency:
the conveyor:
in the end,, gear and rack combination
common mechanical efficiency: Archimedes screw (With copper bush): 0. 35 -0. Archimedes screw (65Plastic bushing): 0. 50 -0. 85 ball screw: 0. 75 -0. 85 preloading ball screw: 0. 85 -0. Spur gear: 95 ~ 0. 75 bevel gear: 0. 90 -0. 95 worm gear: 0. 45 -0. Sprocket: 85 ~ 0. 95, 0. 98 speed belt: ~ 0. 96, 0. 98 bearing: ~ 0. 98 friction friction of common model has three parts: 1, the sliding friction: amplitude is roughly the same. 2, viscous friction at zero speed (Static friction)。 The transition from zero speed to the sliding friction is not obvious. Only at very low speed. Impact on the system is unstable, can cause the stick-slip phenomenon. 3, is proportional to the speed of the viscous damping.
see: sliding friction coefficient of steel on steel: ~ 0. 58 steel to steel (Besmear fat): ~ 0. 15 aluminium to steel: ~ 0. Brass for steel 45: ~ 0. 35 copper to steel: ~ 0. 58 plastics for steel: ~ 0. 15, 0. 25 inertia coefficient of Newton's law tells us that the low inertia = high acceleration for a rotating system: M = J & omega; ’M: here (torqueNm)J: the moment of inertia (公斤。 m2)ω’: angular acceleration rd/s2 & omega; ’= M / J (Acceleration = / inertia torque)Low inertia motors: allows high dynamic system. Increase system bandwidth. But don't match the increased load and motor
