Vehicle drive system including drive mode-shifting mechanism for shifting between two-wheel drive and four-wheel drive

A vehicle drive system for a vehicle that includes four wheels and is switchable between a two-wheel-drive mode in which only two of the wheels are driven and a four-wheel-drive mode in which all four of the wheels are driven comprising:

• a transmission;
• a differential gear;
• a drive mode-shifting mechanism positioned between the transmission and the differential gear for shifting between the two-wheel-drive mode and the four-wheel-drive mode, the drive mode-shifting mechanism including a first shaft, a second shaft and a clutch assembly for connecting the first shaft and the second shaft during the four-wheel-drive mode and for disconnecting the first shaft and the second shaft during the two-wheel-drive mode;
• the clutch assembly being operated by an electric motor to effect the shifting between the two-wheel-drive mode in which the first shaft and the second shaft are disconnected and the four-wheel-drive mode in which the first shaft and the second shaft are connected;
• and
• the vehicle drive system being devoid of a differential between the transmission and the drive mode-shifting mechanism.

A vehicle drive system switchable between a two-wheel-drive mode and a four-wheel-drive mode, comprising:

• a drive axle;
• a differential gear connectable to a pair of wheels;
• a drive mode-shifting mechanism for shifting between the two-wheel-drive mode and the four-wheel-drive mode, the drive mode-shifting mechanism including a first shaft forming an input shaft of the differential gear, a second shaft for transmitting power, and a clutch assembly for connecting the first shaft and the second shaft during the four-wheel-drive mode and for disconnecting the first shaft and the second shaft during the two-wheel-drive mode;
• the clutch assembly including a shifting member axially shifted through operation of an electric motor to effect the switching between the four-wheel-drive mode and the two-wheel-drive mode;
• and
• a yoke connected to the drive axle and an end of the second shaft opposite the first shaft for permitting the drive axle and the second shaft to pivot relative to one another.

A vehicle drive system switchable between two-wheel-drive mode and a four-wheel-drive mode comprises:

• a transmission;
• a housing in which is disposed a differential gear connected to a pair of wheels and a drive-mode-shifting mechanism;
• the drive-mode-shifting mechanism including a first shaft forming an input shaft for the differential gear, a second shaft for transmitting from the transmission, and a clutch assembly for connecting the first and second shafts during the four-wheel-drive mode and for disconnecting the first and second shafts during the two-wheel-drive mode;
• the first shaft having an outer surface with a first spline directly formed on the outer surface of the first shaft;
• the clutch assembly including an axially movable shifting member having an inner surface with an internal spline formed on the inner surface of the shifting member, the internal spline of the shifting member and the first spline of the first shaft engaging one another in both the two-wheel-drive mode and the four-wheel-drive mode;
• the shifting member being engaged by an element which is operatively connected to an electric motor so that operation of the electric motor axially moves the shifting member between one position in the two-wheel-drive mode in which the first and second shafts are disconnected and another position in the four-wheel-drive mode in which the first and second shafts are connected to one another by the shifting member.