Hinge device and electronic apparatus

1. A hinge device comprising:

a shaft rotatable around an axis thereof; and

a torque imparting portion configured to impart a rotational torque to rotation of the shaft, wherein

the torque imparting portion comprises:

a ring having a shaft insertion hole through which the shaft is inserted with rattling, the ring covering a part of an outer circumferential face of the shaft in the axis direction;

an elastic member that biases the ring in the axis direction from a position displaced from the axis of the shaft; and

an adjuster configured to adjust a force that the elastic member biases the ring, and

the torque imparting portion is configured so that the elastic member biases the ring to press the shaft while catching the shaft at a first opening edge of the shaft insertion hole on one side in the axis direction and at a second opening edge on the other side, and thus impart a rotational torque to the shaft.

2. The hinge device according to claim 1 , wherein

the torque imparting portion further comprises a plate between the first and second opening edges of the ring and an outer circumferential face of the shaft, the plate sliding relative to the outer circumferential face of the shaft.

3. The hinge device according to claim 2 , wherein

the plate comprises:

an arc-shaped first plate disposed between the first opening edge and the outer circumferential face of the shaft; and

an arc-shaped second plate disposed between the second opening edge and the outer circumferential face of the shaft.

4. The hinge device according to claim 2 , wherein

the torque imparting portion further comprises a rotation regulator configured to regulate relative rotation between the ring and the plate.

5. The hinge device according to claim 1 , wherein

the elastic member comprises:

a first coil spring disposed on one side of the ring in the axis direction of the shaft, through which the shaft is inserted; and

a second coil spring disposed on the other side of the ring in the axis direction of the shaft, through which the shaft is inserted, and

when the ring is viewed in the axis direction of the shaft insertion hole, a first biasing point where the first coil spring biases the ring and a second biasing point where the second coil spring biases the ring are located in a diagonal direction of the shaft insertion hole.

6. The hinge device according to claim 1 , wherein

the torque imparting portion further comprises an arm extending from the ring, and

the elastic member is configured so that biasing the arm biases the ring.

7. The hinge device according to claim 1 , further comprising:

a clutch configured to disconnect a rotational torque that the torque imparting portion imparts to the shaft, wherein

the clutch comprises:

a lever protruding from the ring; and

a driver configured to rotate the lever, and

when the driver rotates the lever, the clutch rotates the ring against the biasing force from the elastic member to a released posture where the first opening edge and the second opening edge have a gap with the shaft.

8. The hinge device according to claim 7 , wherein

the clutch further comprises a stopper that, when the ring has the released posture, comes into contact with the lever to regulate a further rotation of the lever.

9. The hinge device according to claim 7 , further comprising an automatic rotation mechanism configured to automatically rotate the shaft in a predetermined rotation direction in response to disconnection of the rotational torque by the clutch.

10. An electronic apparatus comprising:

a first chassis;

a second chassis adjacent to the first chassis; and

a hinge device comprising:

a shaft rotatable around an axis thereof; and

a torque imparting portion configured to impart a rotational torque to rotation of the shaft, wherein

the hinge device connecting the first chassis and the second chassis in a relatively rotatable manner,

the torque imparting portion comprises:

a ring having a shaft insertion hole through which the shaft is inserted with rattling, the ring covering a part of an outer circumferential face of the shaft in the axis direction;

an elastic member that biases the ring in the axis direction from a position displaced from the axis of the shaft; and

an adjuster configured to adjust a force that the elastic member biases the ring, and

the torque imparting portion is configured so that the elastic member biases the ring to press the shaft while catching the shaft at a first opening edge of the shaft insertion hole on one side in the axis direction and at a second opening edge on the other side, and thus impart a rotational torque to the shaft.

11. The electronic apparatus according to claim 10 , wherein

the hinge device further comprises:

a clutch configured to disconnect a rotational torque that the torque imparting portion imparts to the shaft; and

an automatic rotation mechanism configured to automatically rotate the shaft in a predetermined rotation direction in response to disconnection of the rotational torque by the clutch.

12. The electronic apparatus according to claim 11 , further comprising:

a second hinge device comprising:

a second shaft rotatable around an axis thereof; and

a second torque imparting portion configured to impart a rotational torque to rotation of the second shaft, wherein

the second hinge device and the hinge device connect the first chassis and the second chassis in a relatively rotatable manner,

the second torque imparting portion is configured so that a flat spring fixed to the second shaft is pressed against a bracket fixed to one of the first and second chassis and relatively rotatably connected to the second shaft, or so that the second shaft is press-fitted in a relatively rotatable manner to a curl portion of a bracket fixed to one of the first and second chassis.