Planetary Gear

Aim : 1)To model planetary geartrain of given specification

2)To carryout motion analysis of planetary geartrain using solid works.

3)To plot the angular velocity at output for all cases.

Introduction:

Planetary gear train is special type of geartrain made by the combination of external spur gears and internal spur gears. basic structure is similar to planetary system.consisting of one central gear also called as sun gear.It is meshed with one or more gears called planet gears and furthur planet gears are mesh with big internal spur gear called as ring gears.shafts of planets are connected again and coupled to central shaft which is coaxial with sun gear shaft. this arrangement is called as carrier.carrier output is further connected to next sun gear output to form next stage.

application -

1)planetary gears are used when there is weight and space contraints and large torque requirements.

2)planetary geartrain is basic unit of automatic transmission system.

In motion study analysis we study behaviour of kinematical quantities such as displacement,velocity,acceleration at output by providing certain input.

for motion analysis of planetary gear train we consider following cases-

CASES	INPUT	OUTPUT	FIXED
CASE1	SUN	CARRIER	RING
CASE2	RING	CARRIER	SUN
CASE3	SUN	RING	CARRIER

specifcations of planetary geartrian -

GEAR	MODULE	TEETH	PITCH CIRCLE DIAMETER
SUN	2.5	14	35
PLANET	2.5	16	40
RING	2.5	46	115

Calculation of no. of planetary teeth -

from geomerty,

pitch circle radius of ring = pitch circle radius of sun +pitch circle diameter of planets,

(115/2) = 17.5+x,

x = 40.

procedure for assembly -

1)toolbox -ansi metric-power tranmission elements-gears-internal/external gears.

2)specify module,number of teeth, nominal shaft dia,face width etc.

3)assemble geartrain by proper mates based on requirement of cases.

4)plot angular velocity at output for 200 rpm provided at input

planetary geartrain assembly-

case1)

plot-

case-2)

plot -

case-3)

plot -