Differential gear drives are used frequently in motor vehicles, in order to compensate for different rates of rotation of driven wheels. In the case of lockable differentials, two kinds are generally differentiated between. One is a lockable differential, which is put into the locked state by an external activation apparatus, in which, by the activation of the said external activation apparatus, the differential action of the differential can be partially or fully withheld. The other is the self-acting, locking differential. In the case of the self acting differential, the locking action is based on interior friction, which opposes the differential motion. Usually, for both kinds of the differential, lamellar clutches are employed for the suspension of the differential activity.
DE 195 47 980 A1 discloses a differential gear drive, which develops, by means of the varied speed of rotation of the driven wheels, a braking torque. This said torque partially suspends the differential action of the differential drive. In this case, the differential cage comprises two parts, which are connected by means of bolts. A bevel gear, which is driven by a drive pinion, is connected to the differential cage by an additional bolt fastening.
DE 38 39 787 C2 makes known a differential drive, in which case the differential effect of the said drive can be suspended by means of an external activation of an activation apparatus. The differential cage of the differential drive consists of two parts, wherein one part of the differential cage is driven. The fastening of the drive gear is not shown.
The purpose of the present invention is to create a differential drive, wherein the drive pinion and the driven bevel gear, which is connected to the differential cage, as well as a principal component of the differential cage and the therein employed differential bevel gears, can serve as,an external lockable differential drive as well as a self-acting lockable differential drive.
In accordance with the invention, the driven bevel gear, which is connected with the differential cage, is so designed, that it possesses two, oppositely disposed contact faces. Of these two, the first contact face serves as seat for the clutch lamina which serve for the locking of the differential motion by externally activated locking means. The second contact face, which lies opposite the first contact face, serves as a seat for a clutch in a self-locking differential drive. The differential cage possesses on the one hand, an opening, through which the installation of the differential gears is made and which also possesses a space in which the clutches, in the case of a self-locking differential drive can be installed and on the other hand, possesses a first contact face for the bearing of the differential cage in the axle housing. The drive side differential bevel gears, which are to be found in the differential cage, possess fastening points for the securing of the inner laminae of the clutches for locking the differential drive. The driven bevel gear is so fastened as to turn in common with the differential cage and partially closes the opening of the differential cage, whereby, the second contact face, which serves as a seat for the clutch of the self-locking differential drive, can extend itself into the said differential cage. The driven bevel gear, which, as said, is rotatably affixed to the differential cage, is located between the differential cage and a cover, which cover is affixed by fastening elements with both the driven bevel gear and the differential cage, and possesses moreover a second location for the setting of the differential drive in bearings in the axle housing. While the driven bevel gear is placed between the cover and the differential cage, it becomes possible, in accord with the individual circumstances, to permit the clutches to seat upon the said contact faces of the bevel gear. Different covers are used, if the lockable differential drive is to function as a self-locking drive or be activated by an external activation apparatus. By means of this arrangement, it is possible, in the case of a self-locking differential drive and also in the case of an externally activated locking differential drive, to make the principal components of the differential cage, the differential bevel gears in the differential cage, and the driven bevel gear, without any changes. If a split axle housing is employed, which, can, possibly, encapsulate the differential drive, then, additionally, this part, which extends over the differential drive, can also, for both kinds of differential drives, be made and shaped the same. By this means, it is possible to create an assembly method, in which both kinds of differential drives, with many identical components can be manufactured.