Reaction force pedal device

1. A reaction force pedal device comprising:

a pedal member operable by a driver and configured to be moved between a non-actuated and actuated positions thereof;

a motor having a rotatable output shaft for applying a reaction force to the pedal member through an arm member, which is coupled at all times to the pedal member;

a clutch disposed between the motor output shaft and the arm member; and

an electronic control unit (ECU) configured to control operations of the motor,

wherein while the pedal member is being returned toward the non-actuated position thereof, the clutch is temporarily disengaged and the motor is deactivated by the ECU so that a rotational angle of the motor output shaft is not changed in relation to movement of the pedal member.

2. The reaction force pedal device according to claim 1 , wherein:

the pedal member includes an accelerator pedal and the reaction force pedal device further comprises a sensor for detecting actuation of the accelerator pedal;

a threshold value is established with respect to a depressed amount of the accelerator pedal or with respect to a change per unit time in the depressed amount of the accelerator pedal;

the ECU is configured to judge, based on an output of the sensor and the threshold value, whether or not the accelerator pedal is being returned toward the non-actuated position thereof, or whether or not the accelerator pedal is being returned toward the non-actuated position thereof at least a predetermined speed; and

the ECU is configured to control the motor so that the rotational angle of the motor output shaft is not changed if the accelerator pedal is being returned toward the non-actuated position thereof at a change per unit time which exceeds the threshold value.

3. The reaction force pedal device according to claim 1 , further comprising:

a speed reducer disposed between the motor output shaft and the arm member,

wherein the clutch is disposed between the speed reducer and the motor output shaft.

4. The reaction force pedal device according to claim 1 , further comprising:

a speed reducer disposed between the motor output shaft and the arm member,

wherein the speed reducer has a speed reduction ratio set such that the motor output shaft rotates through an angle equal to or greater than 360° when the arm member is fully displaced through a displaceable range thereof.

5. The reaction force pedal device according to claim 1 , wherein the ECU is configured to energize the motor to eliminate backlash in a force transmitting system from the motor to the pedal member even when it is unnecessary to generate the reaction force from the motor.

6. The reaction force pedal device according to claim 1 , further comprising:

a biasing member for applying a biasing force at all times independently of the motor in a direction in which the reaction force is generated by the motor to eliminate backlash in a force transmitting system from the motor to the pedal member.

7. The reaction force pedal device according to claim 6 , further comprising:

a second speed reducer disposed between the motor output shaft and the biasing member to reduce a rotational angle of the output shaft of the motor which is produced under the biasing force from the biasing member.

8. A reaction force pedal device comprising:

a pedal member operable by a driver and configured to be moved between a non-actuated and actuated positions thereof;

a motor having a rotatable output shaft for applying a reaction force to the pedal member through an arm member, which is coupled at all times to the pedal member;

a clutch disposed between the motor output shaft and the arm member, and configured to be temporarily disengaged while the pedal member returns toward the non-actuated position thereof; and

an electronic control unit (ECU) configured to control operations of the motor so that a rotational angle of the motor output shaft is not changed while the pedal member returns toward the non-actuated position thereof.

9. The reaction force pedal device according to claim 8 , wherein:

the pedal member includes an accelerator pedal and the reaction force pedal device further comprises a sensor for detecting actuation of the accelerator pedal;

a threshold value is established with respect to a change per unit time in the depressed amount of the accelerator pedal;

the ECU is configured to judge, based on an output of the sensor and the threshold value, whether or not the accelerator pedal is being returned toward the non-actuated position thereof at least a predetermined speed; and

when the clutch is temporarily disengaged the ECU is configured to control the motor so that the rotational angle of the motor output shaft is not changed if the accelerator pedal is being returned toward the non-actuated position thereof at more than the threshold value.