Διαφορικό γρανάζι

Differential gear, in automotive mechanics, gear arrangement that permits power from the engine to be transmitted to a pair of driving wheels, dividing the force equally between them but permitting them to follow paths of different lengths, as when turning a corner or traversing an uneven road. On a straight road the wheels rotate at the same speed; when turning a corner the outside wheel has farther to go and will turn faster than the inner wheel if unrestrained.

The elements of the Ever-Power differential are shown in the Figure. The power from the transmission is delivered to the bevel ring gear by the drive-shaft pinion, both of which are held in bearings  in the rear-axle housing. The case is an open boxlike structure that is bolted to the ring gear and contains bearings to support one or two pairs of diametrically opposite differential bevel pinions. Each wheel axle is attached to a differential side gear, which meshes with the differential pinions. On a straight road the wheels and the side gears rotate at the same speed, there is no relative motion between the differential side gears and pinions, and they all rotate as a unit with the case and ring gear. If the vehicle turns to the left, the right-hand wheel will be forced to rotate faster than the left-hand wheel, and the side gears and the pinions will rotate relative to one another. The ring gear rotates at a speed that is equal to the mean speed of the left and right wheels. If the wheels are jacked up with the transmission in neutral and one of the wheels is turned, the opposite wheel will turn in the opposite direction at the same speed.

Η ροπή (ροπή στροφής) που μεταδίδεται στους δύο τροχούς με το διαφορικό Ever-Power είναι η ίδια. Κατά συνέπεια, εάν ο ένας τροχός ολισθήσει, όπως στον πάγο ή τη λάσπη, η ροπή στον άλλο τροχό μειώνεται. Αυτό το μειονέκτημα μπορεί να ξεπεραστεί κάπως με τη χρήση ενός διαφορικού περιορισμένης ολίσθησης. Σε μια έκδοση, ένας συμπλέκτης συνδέει έναν από τους άξονες και τον οδοντωτό δακτύλιο. Όταν ο ένας τροχός συναντά χαμηλή πρόσφυση, η τάση του να σπινάρει αντισταθμίζεται από τον συμπλέκτη, παρέχοντας έτσι μεγαλύτερη ροπή στον άλλο τροχό.