Electric brake device

1. An electric brake device installed on a vehicle, comprising:

a rotary body to rotate with a wheel;

a friction member to be pushed onto the rotary body;

an actuator including an electric motor as a drive source to cause the friction member to be pushed onto the rotary body; and

a controller to control a braking force generated by the electric brake device by controlling a supply current supplied to the electric motor,

wherein the controller determines, by mutually different methods, a plurality of target supply current components each of which is a component of a target supply current as a target of the supply current, determines the target supply current by adding up the target supply current components, and changes contribution degrees of the respective target supply current components in the determination of the target supply current in accordance with a characteristic of the braking force to be generated,

wherein the target supply current components include:

a motor-rotation-speed-dependent component including a feedback component based on a motor rotation speed deviation that is a deviation of an actual rotation speed of the electric motor from a target motor rotation speed as a target of a rotation speed of the electric motor; and

a supply-current-dependent component including a feedback component based on a supply current deviation that is a deviation of an actual supply current from the target supply current.

2. The electric brake device according to claim 1 ,

wherein the braking force required to be generated by the electric brake device is defined as a required braking force and a change in the required braking force is defined as a required braking force change,

wherein the controller increases the contribution degree of the motor-rotation-speed-dependent component in the determination of the target supply current when a degree of the required braking force change based on a brake operation by a driver of the vehicle becomes larger than a set degree, and

wherein the controller increases the contribution degree of the supply-current-dependent component in the determination of the target supply current when the degree of the required braking force change based on the brake operation by the driver of the vehicle becomes equal to or smaller than the set degree.

3. The electric brake device according to claim 2 ,

wherein the controller increases the contribution degree of the motor-rotation-speed-dependent component in the determination of the target supply current by keeping the feedback component of the supply-current-dependent component at a fixed value until the motor rotation speed deviation becomes larger than a set deviation, and

wherein the controller increases the contribution degree of the supply-current-dependent component in the determination of the target supply current by keeping the feedback component of the motor-rotation-speed-dependent component at a fixed value until the supply current deviation becomes larger than a set deviation.

4. The electric brake device according to claim 2 ,

wherein the controller determines the target supply current by adding up the motor-rotation-speed-dependent component and the supply-current-dependent component after weights are assigned to the motor-rotation-speed-dependent component and the supply-current-dependent component,

wherein the controller increases the contribution degree of the motor-rotation-speed-dependent component in the determination of the target supply current by changing the weights such that the motor-rotation-speed-dependent component is more largely weighted than the supply-current-dependent component, and

wherein the controller increases the contribution degree of the supply-current-dependent component in the determination of the target supply current by changing the weights such that the supply-current-dependent component is more largely weighted than the motor-rotation-speed-dependent component.

5. The electric brake device according to claim 4 , wherein the weights are changed so as to be gradually changed.

6. The electric brake device according to claim 1 , wherein the target supply current components further include a pushing-force-dependent component including a feedback component based on a pushing force deviation that is a deviation of an actual pushing force from a target pushing force as a target of a pushing force by which the friction member is pushed onto the rotary body by the actuator.

7. The electric brake device according to claim 6 ,

wherein the braking force required to be generated by the electric brake device is defined as a required braking force and a change in the required braking force is defined as a required braking force change,

wherein the controller increases the contribution degree of the motor-rotation-speed-dependent component in the determination of the target supply current when a degree of the required braking force change based on a brake operation by a driver of the vehicle becomes larger than a set degree,

wherein the controller increases the contribution degree of the supply-current-dependent component in the determination of the target supply current when the degree of the required braking force change based on the brake operation by the driver of the vehicle becomes equal to or smaller than the set degree, and

wherein the controller increases the contribution degree of the pushing-force-dependent component in the determination of the target supply current when a braking force request not based on the brake operation by the driver of the vehicle is made.

8. The electric brake device according to claim 7 ,

wherein the controller increases the contribution degree of the motor-rotation-speed-dependent component in the determination of the target supply current by keeping the feedback components of the supply-current-dependent component and the pushing-force-dependent component at respective fixed values until the motor rotation speed deviation becomes larger than a set deviation,

wherein the controller increases the contribution degree of the supply-current-dependent component in the determination of the target supply current by keeping the feedback components of the motor-rotation-speed-dependent component and the pushing-force-dependent component at respective fixed values until the supply current deviation becomes larger than a set deviation, and

wherein the controller increases the contribution degree of the pushing-force-dependent component in the determination of the target supply current by keeping the feedback components of the motor-rotation-speed-dependent component and the supply-current-dependent component at respective fixed values until the pushing force deviation becomes larger than a set deviation.

9. The electric brake device according to claim 7 ,

wherein the controller determines the target supply current by adding up the motor-rotation-speed-dependent component, the supply-current-dependent component, and the pushing-force-dependent component after weights are assigned to the motor-rotation-speed-dependent component, the supply-current-dependent component, and the pushing-force-dependent component,

wherein the controller increases the contribution degree of the motor-rotation-speed-dependent component in the determination of the target supply current by changing the weights such that motor-rotation-speed-dependent component is more largely weighted than the supply-current-dependent component and the pushing-force-dependent component,

wherein the controller increases the contribution degree of the supply-current-dependent component in the determination of the target supply current by changing the weights such that the supply-current-dependent component is more largely weighted than the motor-rotation-speed-dependent component and the pushing-force-dependent component, and

wherein the controller increases the contribution degree of the pushing-force-dependent component in the determination of the target supply current by changing the weights such that the pushing-force-dependent component is more largely weighted than the motor-rotation-speed-dependent component and the supply-current-dependent component.

10. The electric brake device according to claim 9 , wherein the weights are changed so as to be gradually changed.