Abstract: In a four-wheel-drive vehicle having auxiliary drive wheels to which power of a drive power source is transmitted via a transmission member, in which connecting/disconnecting devices are provided between the drive power source and the transmission member and between the transmission member and the auxiliary drive wheels such that one of the connecting/disconnecting devices is a friction engagement clutch while the other is a dog clutch, when switching from two-wheel-drive running mode in which both the clutches are disconnected to four-wheel-drive running mode, an acceleration/deceleration adaptive synchronization portion sets an allowable deceleration based on a vehicle acceleration/deceleration and controls an engagement torque of the friction engagement clutch to make the deceleration of the vehicle equal to the allowable deceleration when the rotation speed of the transmission member is increased.

Abstract: A wet multi-plate clutch includes: a piston movable between a transmission position where the piston pushes a clutch plate group including a plurality of inside clutch plates supported on an inside cylinder and a plurality of outside clutch plates supported on an outside cylinder, in an axial direction to cause friction between the inside and outside clutch plates, and a disconnection position where the piston is spaced apart from the clutch plate group; and a movable wall configured to move integrally with the piston. The disconnection position includes a first disconnection position and a second disconnection position where the distance between the clutch plate group and the piston is longer than at the first disconnection position. When the piston is positioned at the first disconnection position, a first through hole provided in the inside cylinder and a second through hole provided in the movable wall overlap in the radial direction.

Abstract: According to one embodiment, for example, a transfer control device controls a transfer that adjusts torque distribution to front wheels and rear wheels of a four-wheel vehicle and that includes a wet type multi-disc clutch and a piston. The transfer control device includes: a detector that detects, based on an output value of a sensor provided in the vehicle, whether a predetermined condition corresponding to a state immediately before ignition of the vehicle is turned ON is established; a controller that starts moving the piston when the detector detects that the predetermined condition is established, so that the multi-disc clutch is switched to a connected state from a disconnected state; and a storage that stores therein, while the piston is moved by the controller, information on a connection start state at which connection of the multi-disc clutch is started.

Abstract: In a four-wheel-drive vehicle having auxiliary drive wheels to which power of a drive power source is transmitted via a transmission member, in which connecting/disconnecting devices are provided between the drive power source and the transmission member and between the transmission member and the auxiliary drive wheels such that one of the connecting/disconnecting devices is a friction engagement clutch while the other is a dog clutch, when switching from two-wheel-drive running mode in which both the clutches are disconnected to four-wheel-drive running mode, an acceleration/deceleration adaptive synchronization portion sets an allowable deceleration based on a vehicle acceleration/deceleration and controls an engagement torque of the friction engagement clutch to make the deceleration of the vehicle equal to the allowable deceleration when the rotation speed of the transmission member is increased.