Input device

1. An input device comprising:

a fixed unit;

a rotary member rotatably supported by the fixed unit;

a rotation-detecting unit that detects a rotation angle of the rotary member;

a brake-applying unit that applies a braking force to the rotary member;

a torque-applying unit that applies a driving torque to the rotary member; and

a control unit that controls the brake-applying unit and the torque-applying unit,

wherein the brake-applying unit includes:

magnetorheological fluid;

a brake-applying coil that applies a magnetic field to the magnetorheological fluid;

a shaft to which braking torque that changes with viscosity of the magnetorheological fluid is applied; and

a transmission gear provided on the shaft, the transmission gear being in mesh with a gear provided on the rotary member,

wherein the shaft is positioned on an outer side with respect to the rotary member in a radial direction of the rotary member,

wherein the fixed unit is made of a non-magnetic material and includes a cylindrical supporting portion extending in a direction of a rotation axis of the rotary member,

wherein the torque-applying unit includes:

a plurality of torque-applying coils arranged in a circumferential direction of an outer circumferential surface of the supporting portion; and

a magnet that faces the plurality of torque-applying coils with an interval, the magnet being annular and provided on an outer side with respect to the plurality of torque-applying coils,

wherein the magnet is positioned on an inner side with respect to the rotary, member and rotates along with the rotary member, and

wherein the control unit controls current to be supplied to the plurality of torque-applying coils, the current being controlled in accordance with the rotation angle of the rotary member.

2. The input device according to claim 1 ,

wherein the brake-applying unit includes a rotary plate connected to the shaft, and a yoke that induces the magnetic field generated by the brake-applying coil,

wherein the yoke faces one side of the rotary plate and the other side of the rotary plate with respective gaps in between such that the magnetic field passes through the rotary plate from the one side to the other side,

wherein the magnetorheological fluid is provided in the gaps, and

wherein the control unit controls current to be supplied to the brake-applying coil, the current being controlled in accordance with the rotation angle of the rotary member.

3. The input device according to claim 1 ,

wherein the gear includes a first gear and a second gear,

wherein the first gear is fixed to the rotary member, and

wherein the second gear has teeth arranged at a pitch equal to a pitch of teeth of the first gear, the second gear being urged in a circumferential direction such that the pitches are staggered.

4. The input device according to claim 1 , further comprising:

a frame that connects the fixed unit and the brake-applying unit to each other; and

a strain gauge that detects strain occurring in the frame.

5. An input device comprising:

a fixed unit;

a rotary member rotatably supported by the fixed unit;

a rotation-detecting unit that detects a rotation angle of the rotary member;

a brake-applying unit that applies a braking force to the rotary member;

a torque-applying unit that applies a driving torque to the rotary member;

a control unit that controls the brake-applying unit and the torque-applying unit;

a frame that connects the fixed unit and the brake-applying unit to each other, the frame having a pair of vertical sidewalls to which the brake-applying unit is fixed; and

a strain gauge that detects strain occurring in the frame,

wherein the brake-applying unit includes:

magnetorheological fluid;

a brake-applying coil that applies a magnetic field to the magnetorheological fluid;

a shaft to which braking torque that changes with viscosity of the magnetorheological fluid is applied; and

a transmission gear provided on the shaft, the transmission gear being in mesh with a gear provided on the rotary member,

wherein the shaft is positioned on an outer side with respect to the rotary member in a radial direction of the rotary member, and

wherein the strain gauge is provided on one of the pair of vertical sidewalls of the frame.

6. The input device according to claim 5 ,

wherein the fixed unit is made of a non-magnetic material and includes a cylindrical supporting portion extending in a direction of a rotation axis of the rotary member,

wherein the torque-applying unit includes:

a plurality of torque-applying coils arranged in a circumferential direction of an outer circumferential surface of the supporting portion; and

a magnet that faces the plurality of torque-applying coils with an interval, the magnet being annular and provided on an outer side with respect to the plurality of torque-applying coils,

wherein the magnet is positioned on an inner side with respect to the rotary member and rotates along with the rotary member, and

wherein the control unit controls current to be supplied to the plurality of torque-applying coils, the current being controlled in accordance with the rotation angle of the rotary member.

7. The input device according to claim 5 ,

wherein the brake-applying unit includes a rotary plate connected to the shaft, and a yoke that induces the magnetic field generated by the brake-applying coil,

wherein the yoke faces one side of the rotary plate and the other side of the rotary plate with respective gaps in between such that the magnetic field passes through the rotary plate from the one side to the other side,

wherein the magnetorheological fluid is provided in the gaps, and

wherein the control unit controls current to be supplied to the brake-applying coil, the current being controlled in accordance with the rotation angle of the rotary member.

8. The input device according to claim 5 ,

wherein the gear includes a first gear and a second gear,

wherein the first gear is fixed to the rotary member, and

wherein the second gear has teeth arranged at a pitch equal to a pitch of teeth of the first gear, the second gear being urged in a circumferential direction such that the pitches are staggered.