Driving power distribution apparatus and method for controlling torque coupling

A driving power distribution apparatus provided in a vehicle, the vehicle having a driving power source, wheels, and a driving power transmission system that transmits torque from the driving power source to the wheels, the driving power transmission system being provided with a driving power transmission member, the apparatus comprising:

• a torque coupling provided in the driving power transmission system, the torque coupling being provided with a clutch mechanism and being capable of changing an amount of torque transmission by adjusting an engaging force of the clutch mechanism;
• a control section that controls operation of the torque coupling through adjustment of the engaging force;
• a temperature estimating section that estimates the temperature of the driving power transmission member;
• an acceleration detecting section that detects the acceleration of the vehicle;
• and
• a determining section that determines whether or not load of the driving power source is high based on an estimated vehicle acceleration, which is computed based on a predetermined vehicle weight and an output torque of the driving power source, and an actual vehicle acceleration, which is detected by the acceleration detecting section,
• wherein the control section is capable of switching control of the torque coupling between normal control and overheat prevention control for reducing the amount of torque transmission,
• wherein, when an estimated temperature of the driving power transmission member that is estimated by the temperature estimating section is higher than or equal to a first reference temperature, the control section switches the control of the torque coupling from the normal control to the overheat prevention control,
• wherein, when the determining section determines that the load of the driving power source is high, the control section executes at least one of the following processes in order to facilitate the switching from the normal control to the overheat prevention control:
• (a) correcting the estimated temperature of the driving power transmission member such that the estimated temperature is raised by a predetermined degree;
• and
• (b) changing the first reference temperature to a second reference temperature that is lower than the first reference temperature.