Abstract: A dog clutch mechanism for use as a clutch for switching drive power in a four-wheel-drive vehicle has a case, first and second rotatable shafts rotatably supported coaxially in the case for transmitting a relative torque between front and rear wheels of the vehicle, and a dog clutch comprising a dog piece having first dog teeth and fixedly mounted on the first rotatably shaft and a hub having second dog teeth capable of axially meshing with the first dog teeth and axially slidably mounted on the second rotatable shaft. The dog clutch is selectively engageable for transmitting the relative torque between the first and second rotatable shafts. The first and second dog teeth having respective meshing tapered surfaces for producing thrust forces acting on the hub and tending to move the hub in a direction away from the dog piece when the vehicle is braked while a relative forward torque is being transmitted between the first and second rotatable shafts through the dog clutch.

Abstract: A dog clutch mechanism includes a case, first and second rotatable shafts rotatably disposed coaxially in the case, the second rotatable shaft having an annular groove defined in an outer periphery thereof, a dog piece fixedly mounted on the first rotatable shaft and having first dog teeth confronting an end of the second rotatable shaft, a hub axially slidably mounted on the second rotatable shaft and having second dog teeth meshingly engageable with the first dog teeth, the second dog teeth being movable out of meshing engagement with the first dog teeth under a thrust force in response to relative torque transmission between the first and second rotatable shafts. The hub has guide holes extending radially therethrough toward the second rotatable shaft and a plurality of balls are retained respectively in the guide holes are and engageable in the annular groove.