Control device for controlling drive force that operates on vehicle

1. A control device for controlling a front wheel drive force and a rear wheel drive force of a vehicle that includes a transmission, the control device comprising:

first control means for controlling a drive force of a main drive wheel and a drive force of an auxiliary drive wheel, the drive force of the main drive wheel being one of the front-wheel drive force and the rear-wheel drive force, and the drive force of the auxiliary drive wheel being another of the front-wheel drive force and the rear-wheel drive force; and

second control means for detecting whether a speed-change ratio of the transmission has changed,

wherein

the first control means increases the drive force of the auxiliary drive wheel and reduces the drive force of the main drive wheel when the second control means has detected that the speed-change ratio of the transmission has increased, and the first control means increases the drive force of the auxiliary drive wheel and reduces the drive force of the main drive wheel when the second control means has detected that the speed-change ratio of the transmission has decreased.

2. The control device according to claim 1 , wherein

the second control means has a permission unit for permitting the first control means to increase the drive force of the auxiliary drive wheel when a predetermined condition has been satisfied, wherein

the predetermined condition is at least one of a) that a slippage amount of the main drive wheel is equal to or greater than a first predetermined value, b) that a first coefficient which depends on a traveling state of the vehicle is equal to or greater than a second predetermined value, c) that a motor drive force is equal to or greater than a third predetermined value, and d) that a speed of the vehicle is equal to or less than a fourth predetermined value;

the traveling state includes at least one of a parameter or a steer angle, and the parameter represents an inertial force that acts on the vehicle when the vehicle is making a turn; and

the first coefficient is smaller in proportion to a greater magnitude of at least one of the parameter and the steer angle.

3. The control device according to claim 1 , wherein

the first control means is a drive force control means, and the second control means is a vehicle behavior control means.

4. A control device for controlling a front wheel drive force and a rear wheel drive force of a vehicle that includes a transmission, the control device comprising:

first control means for controlling a drive force of a main drive wheel and a drive force of an auxiliary drive wheel, the drive force of the main drive wheel being one of the front-wheel drive force and the rear-wheel drive force, and the drive force of the auxiliary drive wheel being another of the front-wheel drive force and the rear-wheel drive force; and

second control means for detecting whether a speed-change ratio of the transmission has changed,

wherein

the second control means has:

a detection unit for detecting whether the speed-change ratio of the transmission has changed;

a first calculation unit for calculating a first drive force that represents an amount of increase in the drive force of the auxiliary drive wheel;

a second calculation unit for calculating a second drive force for limiting the first drive force, and

wherein

in a case that the detection unit has detected that the speed-change ratio has changed, the first control means increases the drive force of the auxiliary drive wheel by an amount commensurate to a smallest drive force among the first drive force and the second drive force, and reduces the drive force of the main drive wheel, and

the second calculation unit calculates the second drive force on the basis of a motor drive force and a first coefficient, and the first coefficient depends on a traveling state of the vehicle.

5. The control device according to claim 4 , wherein

the first calculation unit calculates the first drive force on the basis of a slippage amount of the main drive wheel.

6. The control device according to claim 4 , wherein

the traveling state includes at least one of a parameter and a steer angle, wherein the parameter represents an inertial force that acts on the vehicle when the vehicle is making a turn; and

the first coefficient is smaller in proportion to a greater magnitude of at least one of the parameter and the steer angle.

7. The control device according to claim 4 , wherein

the second calculation unit calculates the second drive force on the basis of the motor drive force, the first coefficient, and a second coefficient; and

the second coefficient is smaller in proportion to a higher speed of the vehicle.

8. The control device according to claim 4 , wherein

the first control means increases the drive force of the auxiliary drive wheel and reduces the drive force of the main drive wheel when the second control means has detected that the speed-change ratio of the transmission has increased, and the first control means increases the drive force of the auxiliary drive wheel and reduces the drive force of the main drive wheel when the second control means has detected that the speed-change ratio of the transmission has decreased.

9. A vehicle behavior control device for requesting a drive force control device to increase a drive force of an auxiliary drive wheel of a vehicle that includes a transmission, the vehicle behavior control device comprising:

a detection unit for detecting whether a speed-change ratio of the transmission has changed;

a first calculation unit for calculating a first drive force that represents an amount of increase in the drive force of the auxiliary drive wheel; and

a second calculation unit for calculating a second drive force for limiting the first drive force, wherein

in the case that the detection unit has detected that the speed-change ratio has changed, the vehicle behavior control device requests the drive force control device to increase the drive force of the auxiliary drive wheel by an amount commensurate to a smallest drive force among the first drive force and the second drive force, and

the second calculation unit calculates the second drive force on the basis of a motor drive force and a first coefficient, and the first coefficient depends on a traveling state of the vehicle.

10. The vehicle behavior control device according to claim 9 , wherein

in the case that the detection unit has detected that the speed-change ratio has changed, the drive force control device reduces the drive force of a main drive wheel by an amount commensurate to the smallest drive force.

11. The vehicle behavior control device according to claim 9 , wherein

the traveling state includes at least one of a parameter and a steer angle, wherein the parameter represents an inertial force that acts on the vehicle when the vehicle is making a turn; and

the first coefficient is smaller in proportion to a greater magnitude of at least one of the parameter and the steer angle.

12. The vehicle behavior control device according to claim 9 , wherein

the second calculation unit calculates the second drive force on the basis of the motor drive force, the first coefficient, and a second coefficient; and

the second coefficient is smaller in proportion to a higher speed of the vehicle.

13. The vehicle behavior control device according to claim 9 , wherein

the vehicle behavior control device requests the drive force control device to increase the drive force of the auxiliary drive wheel by the amount commensurate to the smallest driving force when the detection unit has detected that the speed-change ratio has increased, and the vehicle behavior control device requests the drive force control device to increase the drive force of the auxiliary drive wheel by the amount commensurate to the smallest driving force when the detection unit has detected that the speed-change ratio has decreased.