Work machines, such as articulated trucks, off-road machines, on-road machines, motor graders, dozers, and the like may be used in mining, construction, agriculture, petroleum, and other such industrial applications. During operation, the work machine may travel and maneuver around a work site that includes a variety of different terrains such as, steep inclines and descents, loose gravel and dirt, sharp turns, uneven pathways, and other such variable terrain. Furthermore, the work machine may be configured to haul or otherwise transport heavy loads from one location of the work site to another. In some cases, transporting heavy loads across the variable terrain may affect the traction and mobility of the work machine. As a result, the work machine power train may be configured to deliver power and torque to the drive axles based on the response of the work machine to the variable terrain, heavy loads, and other such operational conditions.
Typically, the work machine may include one or more differential assemblies incorporated into the power train. Furthermore, the differential assembly may be disposed or otherwise positioned between the right and left axle shaft of each drive axle. Furthermore, the differential assembly may be configured to transfer torque and power to right and left axle shafts of the drive axle. The differential assembly may include one or more operational modes such as an open mode and a locked mode. When the differential assembly operates in the open mode, the right and left axle shafts may be allowed to rotate at different speeds. In the open mode, the torque may be equally distributed between the right and left axle shaft to provide the same rotational force to each ground engaging element (i.e., wheel). However, each ground engaging element may rotate at a different speed. Alternatively, in the locked mode the differential assembly may lock the right and left axle shaft together such that each ground engaging element may be forced to rotate together.
Furthermore, depending on the operational mode, the differential assembly may modify the torque transfer pathway from the differential assembly to the right and left axle shafts. For example, in some differential assemblies the torque may follow a direct path in the open operational mode and an indirect path in the locked operational mode. The indirect torque transfer path may be established through one or more joint faces that are coupled together by bolts, pins, welds, or other such coupling device. However, the joint faces may be repeatedly exposed to friction and other sliding forces during the torque transfer. In some situations, the frictional forces may reduce the efficiency and reliability of the differential assembly. As a result, it may be desired to configure the differential assembly to provide a direct torque transfer pathway in both the open and locked operational modes.
A differential for a vehicle is disclosed in U.S. Pat. No. 8,043,188 entitled, “Spider-less Vehicle Differential,” (the '188 patent). The differential disclosed therein is equipped with a ring gear having a plurality of spaced apart recesses. The differential of the '188 patent further includes one side pinion located in each recess of the ring gear. Furthermore, a heel end of the side pinion gear is located against a side pinion seat surface defined in each of the recess of the ring gear. The rotational motion from the ring gear is transferred directly to the side pinions through side walls which are defined by each recess of the ring gear.
While the '188 patent shows a direct rotational force path, it fails to disclose a differential having a locking operational mode which utilizes the direct rotational force transfer pathway.