Front-rear wheel driving force distribution device and front-rear wheel driving force distribution device controller

A front-rear wheel driving force distribution device to be applied to a vehicle, the front-rear wheel driving force distribution device comprising:

• a center differential configured to distribute and output rotating torque inputted from a transmission of the vehicle to a propeller shaft on a front side and a propeller shaft on a rear side;
• and
• a limited slip differential comprising a first clutch, a second clutch, a first piston configured to engage the first clutch, a second piston configured to engage the second clutch, and a one-way clutch provided between the first clutch and the propeller shaft on the rear side, wherein
• the propeller shaft on the rear side is configured to, in a case where the second clutch is engaged by the second piston, rotate at increased speed as compared with a case where the first clutch is engaged by the first piston, and
• the one-way clutch is configured to
• couple the first clutch and the propeller shaft on the rear side in a case where a number of rotations of the first clutch is same as a number of rotations of the propeller shaft on the rear side or higher than the number of rotations of the propeller shaft on the rear side, and
• idle in a case where the number of rotations of the first clutch is lower than the number of rotations of the propeller shaft on the rear side.