# TORSEN DIFFERENTIAL

Wait……why do we need TORSEN DIFFERENTIAL as we can overcome the problem of traction difference or satisfied with limited slip differential??.

The answer is the LSD technology will allow the drive wheels to slip for limited amount of time before it gets locked. But in TORSEN DIFFERENTIAL technology the locking action is instantaneous i,e as soon as the vehicle encounters the traction difference the wheels get locked and it is compact too.

Before you go through the working I recommend you to go through the concept of worm gear by clicking the previous post .

BASIC COMPONENTS :

1. Pinion gear 2. Ring gear 3. Worm gear      4. Worm wheel 5. Case 6. Spur gear.

WORKING :

The power is transferred from the engine to the differential housing through gear sets ( pinion and ring gears ) causing the housing to rotate. This power flows through the housing to the worm wheels which are attached to it. These worm wheels are in mesh with worm gears attached to the axles causing the axles to turn with the housing. To carry higher loads we can add 2 more worm wheel pairs.

Now we will talk about the cases where it plays it’s role

1. Vehicle moving straight:

We know that when vehicle moves in a straight road both wheels rotate with same angular velocity. When power is transferred from engine to the  differential housing , it is transferred to the worm wheels which are meshed with worm gear. As we know that warm gear can’t spin the worm gear it will just push and turn the worm gear along with it causing the axles to turn and wheels to move forward. Note that In this case there’s no spinning of warm gears. In this condition whole mechanism acts as a single solid unit.

Vehicle taking a right turn:

When a vehicle is taking a right turn left wheel have to cover longer distance than the right wheel so the angular velocity of left wheel should be higher than the right wheel. Before discussing how would it achieve this note that the worm wheel is subjected to relative motion not the absolute motion. The worm wheel is fitted between the case and worm gear, so the relative motion between the case and worm gear is what makes the worm wheel turn. In this situation the worm gear will spin.

When the vehicle is moving forward the worm gear will spin ( let’s say in clockwise direction viewed from left side ) as it is attached to the axle. This spinning action of worm gear will rotate the worm wheel ( let’s say in counter clockwise direction ). The same thing happens with both left and right wheels. As both wheels moves forward the both worm wheels rotate in counter clockwise direction with spur gears attached to it. But  external spur gears never rotate in same direction when it’s meshed. So one of the direction of the spur gear should be reversed. But when we reversed the direction there will be resist to the free movement to the axle so it will rotate slowly than the other wheel. This is exactly how differential works here.

As we are talking about a right turn , the right worm wheel will rotate in opposite direction results in low angular speed of the wheel. The meshing spur gears at the ends of worm wheel will make sure that, the worm wheels are spinning at the same speed. Thus it guarantees a perfect differential action. Perfect differential action implies equal amount of speed loss and speed gain to the right and left wheels.

TRACTION DIFFERENCE:

when a vehicle encounters a situation as left wheel on ground and right wheel the slippery part,  slippery wheel starts to spin very rapidly and will draw the majority of the engine’s power. As a result, the vehicle will get stuck.But, if a Torsen differential is used in this case, as soon as the slippery wheel starts to spin excessively, the speed change will be transferred to the corresponding worm wheel. The right worm wheel transfers the speed change to the left worm wheel, since they are connected through spur gears. Here comes the tricky part! The left side worm wheel will not be able to turn the corresponding worm gear, because, as we said, a worm wheel cannot drive a worm gear! As a result, the whole mechanism gets locked, and the left and right wheels turn together.