Mechanical Engineering

Find A$1$ & A$2$

Problem A

A $6061-$T$6$ shaft is to be used to transfer power between two chain gears $($fixed to the shaft using set screws; see attached drawing for shaft layout$).$ The said shaft will be seated using two bearings chosen by the designer. Available bearings are attached following this instruction. The bearings' housings will be bolted$*$ to a thick steel plate. A force F will be applied to a chain attached to gear $2($located at one end of the shaft$).$

A$1)$ Design the shaft if the chain around gear $1($between the bearings$)$ will be fixed as to prevent the gear from spinning $($design the size, layout, and positions of both bearings and gear $1$ ; the cut$-$out in the plat form below gear $1$ will be moved to match the position of the gear$).$ Also select suitable bearing units, specify the size$($s$)$ for the bolts which will fasten the bearing units, and calculate the torque$($s$)$ required to set the bolts. The following requirements apply:

i$)$ The shaft's factor of safety is between the values specified in the attached spreadsheet under the static loading condition

ii$)$ There should be no gap between the bearing housing and the steel plate under the specified load

A$2)$ If gear $1$ is allowed to spin but the torsional load is maintained to the same level as A$1,$ estimate the number of revolutions the shaft can take before it fails. Use dimensions in the attached spreadsheet for your design.

$L=130mm$

$W=150mm$

$d1={10}^{****}mm(9$ teeth, case$-$hardened carbon steel$)$

$D1=36\mathrm{.}4mm$

$P1=5\mathrm{.}5mm$

$T1=20mm$

$d2={15}^{******}mm(36$ teeth, case$-$hardened carbon steel$)$

$D2=145\mathrm{.}5mm$

$P2=5mm$

$T2=19mm$

$F=8kg$

min FOS $at$ the critical point$(s)=1\mathrm{.}5$

max FOS $at$ the critical point$(s)=2$

hint ; the grars' weights can $be$ estimated

$*$use ISO grade $4\mathrm{.}8$ sockethead bolts $q,$

use Table $1$ available bearing size dimension type kp

Figure $1$ Shaft design layout. Please refer to the attached spread sheet for the dimension