The planet gear is mounted on a moveable arm (carrier) which itself may rotate relative to the sun gear. It is a gear system that consists of one or more outer gear (planet gear) rotating about a central (sun gear). Reverted gear train Epicyclic Gear Train:Įpicyclic gearing also called as planetary gearing. The gear transmission ratio is calculated similarly like a compound gear train.And also the distance between the centers of the two gears in each pair must be the same. If these two gears are mounted on the same shaft, one of them must be loosely mounted. A reverted gear train is also a compound gear train, having the input and output shafts on the same axis (Co-axial).They’re both used when there’s a desire of huge changes in speed or power output but the space for accommodating several gears is restricted. A Reverted gear train is extremely just like a compound gear train.last driven or follower) are co-axial, then the gear train is known as reverted gear train as shown in Fig. Reverted Gear Train:When the axes of the first gear (i.e.
#WORM GEAR DESIGN CALCULATION DRIVER#
Speed Ratio = ( Speed of First Driver / Speed Of Last Driven ) = ( Product of the number of teeth on the driven/ Product of the number of teeth on the driver) Reverted gear train Usually for a speed reduction in excess of 7 to 1, a simple train is not used and a compound train or worm gearing is employed. If a simple gear train is used to give a large speed reduction, the last gear has to be very large. The advantage of a compound train over a simple gear train is that a much larger speed reduction from the first shaft to the last shaft can be obtained with small gears.One of these two gears meshes with the driver and the other with the driven or follower attached to the next shaft as shown in Fig. In this case, each intermediate shaft has two gears rigidly fixed to it so that they may have the same speed.But whenever the distance between the driver and the driven or follower has to be bridged over by intermediate gears and at the same time a great ( or much less ) speed ratio is required, then the advantage of intermediate gears is intensified by providing compound gears on intermediate shafts. But these gears are useful in bridging over the space between the driver and the driven. We have seen in the previous section that the idle gears, in a simple train of gears do not affect the speed ratio of the system.When there is more than one gear on a shaft, as shown in Fig.Speed Ratio = ( Speed of Driver / Speed of Driven ) = ( No. Since the speed ratio (or velocity ratio) of the gear train is the ratio of the speed of the driver to the speed of the driven or follower and ratio of speeds of any pair of gears in mesh is the inverse of their number of teeth, therefore N2 = Speed of gear 2 (or driven or follower) in r.p.m., Let N1 = Speed of gear 1(or driver) in r.p.m.,.To obtain the desired direction of motion of the driven gear (i.e. To connect gears where a large center distance is required, andĢ. b ) are used for the following two purposes:ġ. The idle gears ( Gear number 2 in fig.By providing one or more intermediate gears. The motion from one gear to another, in such a case, maybe transmitted by either of the following two methods :Ģ. Sometimes, the distance between the two gears is large.It may be noted that the motion of the driven gear is opposite to the motion of driving gear.Since the gear 1 drives the gear 2, therefore gear 1 is called the driver and the gear 2 is called the driven or follower. When the distance between the two shafts is small, the two gears 1 and 2 are made to mesh with each other to transmit motion from one shaft to the other, as shown in Fig.When there is only one gear on each shaft, it is known as a simple gear train.But in case of epicyclic gear trains, the axes of the shafts on which the gears are mounted may move relative to a fixed axis. In the first three types of gear trains, the axes of the shafts over which the gears are mounted are fixed relative to each other.
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