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Showing posts with the label Mechanical Engineering

Constant Mesh Gear Box

Constant Mesh In this type of gearbox, all the gears are in constant mesh with the corresponding gears on the layshaft. The gears on the most shaft that is splined, are free (fig). The dog clutches are provided which are free to slide on the main shaft. The gears on the layshaft. are, however, fixed. When the left dog clutch is slide to the left by means that of the selector mechanism, its teeth area unit engaged with those on the clutch gear and that we get the direct gear. The same dog clutch, however, once slide to right makes contact with the gear and gear is obtained. Similarly movement of the right dog clutch to the left results in low gear and towards the right in reverse gear. Double declutching the constant mesh box, for the smooth engagement of the dog, clutches it's necessary that the speed of the main shaft gear and therefore the sliding dog should be equal. Therefore to get lower gear, the speed of the clutch shaft, layshaft, and main shaft gear must be increased. This

Free Wheel Unit

Free Wheel Unit Free Wheel Unit In some vehicles a freewheel unit (also called freewheel clutch) is provided just after the gearbox. Fig. shows the construction of this unit. It is very much similar in action to the bicycle freewheel. The inner driving mem her is connected to the gearbox shaft and the outer one to the propeller shaft. The driving member has the three steps as shown in fig. In each step, there are 3 spring-mounted rollers of various sizes. When the driving member is rotating in the direction shown in the fig. the driven member will also be rotating in the same direction. But when the driven member becomes the driving member e.g., when the car is going downhill with the engine stopped or clutch disengaged, the inner member will not rotate along with the outer one. Thus, during this case, the transmission and the engine will be isolated from the wheels. This results in fuel economy. In some instances, the freewheel has to be locked, e.g. in the reverse drive. In such case

Epicyclic Gear Train

Epicyclic Gear Train An epicyclic gear train (otherwise called planetary gear) comprises of two gears mounted with the goal that the focal point of one gear spins around the focal point of the other. A bearer associates the focuses of the two gears and turns to convey one gear, called the planet gear or planet pinion, around the other, called the sun gear or sun wheel. If the axis of the shafts, over which the gear is compound mounted, are moving relative to the fixed axis, the gear train is known as an epicyclical gear train. In the simple, compound, and reverted gear train, the axis of the shafts is fixed. But in the epicyclic gear train, the shaft axis is not fixed but is moving relative to ' the fixed axis. Use of Epicyclic Gear Train The epicyclic gear trains are useful for transmitting high-velocity ratios with the gear of moderate size in a relatively lesser area. Epicyclic gear train works The working of the epicyclic gearbox can not be clarified quickly as it requires mor

Differential Gear of an Automobile

Differential Gear of an automobile The differential gear used in the rear-drive of an automobile is shown in Fig.1 function is (a) to transmit motion from the engine shaft to the rear driving wheels. (b) To rotate the rear wheels at different speeds while the automobile 15 takes a turn. As long as the automobile 18 running on a straight path, the rear wheels are driven directly by the engine, and the speed of each of the wheels is the same. But when automobile 18 takes a turn, the outer wheel will run faster than the inner wheel because at that time the outer rear wheel has to cover more distance than the inner rear wheel. This is achieved by planet wheel train With bevel gears as shown in Fig. the bevel gear A (known as opinion) is keyed to the propeller shaft is driven from the engine shaft through ' universal coupling. This gear A drives the gear B (known as crown gear) that rotates freely on the shaft P.  Two equal gears C and D are mounted on 2 separate parts P and alphabetic


Inside ignition motors in which the burning of the fuel happens in the motor barrel itself are non-cycle warm motors. The temperature because of the advancement of warmth on account of the ignition of fuel inside the chamber is high to the point that the barrel is cooled by water course around it to evade fast crumbling. The working liquid the fuel-air blend experiences perpetual concoction change because of ignition and the motor, and a new change is taken. So the working liquid does not experience an entire thermodynamic cycle.    To streamline the examination of I.C. motors, air standard cycles are imagined. In an air standard cycle, a specific mass of air works in a total thermodynamic cycle, where warm is included and dismissed with outer warmth repositories, and every one of the procedures the cycle is reversible. Air is thought to be steady. These air standard cycles are conceived to the point that they compare to the task of inside ignition motors. More Posts