Frictional drive device and inverted pendulum type vehicle using the same

1. A frictional drive device, comprising:

a frame;

a pair of drive disks each rotatably supported by the frame around a central axial line in a mutually opposing relationship;

a pair of actuators supported by the frame for individually rotatively actuating the drive disks;

a plurality of drive rollers arranged along an outer periphery of each drive disk and each having a rotational center line so as to be rotatable along a plane which is neither parallel nor perpendicular to the central axial line;

an annular main wheel disposed approximately coaxially with respect to the central axial line and engaged by the drive rollers of the drive disks, the main wheel comprising an annular member and a plurality of driven rollers supported along the annular member so as to be rotatable around a tangential line of the annular member; and

a spring member interposed between each drive roller and the corresponding drive disk to urge the drive roller against the corresponding driven roller,

wherein the main wheel is operable to engage with an object when the main wheel is actuated.

2. The frictional drive device according to claim 1 , wherein the device further comprises a roller bracket rotatably supporting each drive roller, and a peripheral part of each drive disk is provided with a plurality of recesses, each roller bracket being received in the corresponding recess with the spring member being interposed between bottom surfaces of the roller bracket and the recess.

3. The frictional drive device according to claim 1 , wherein the annular member comprises a resilient material for providing resiliency to the annular member, and the device further comprises a pressure member acting upon the main wheel such that the main wheel is engaged by the drive rollers at at least a pair of diametrically opposing positions thereof.

4. The frictional drive device according to claim 3 , wherein the pressure member comprises a guide roller pivotally supported by the frame so as to be rotatable around an axial line parallel to the central axial line of the drive disks, and wherein said guide roller is operable to engage a part of the main wheel diametrically opposing a part of the main wheel engaging the object when the main wheel is actuated.

5. The frictional drive device according to claim 2 , wherein the pressure member applies pressure to the main wheel such that at least a pair of the driven rollers engage the main wheel with the object at all times when the main wheel is actuated.

6. A vehicle using a frictional drive device as defined in claim 1 .

7. A frictional drive device, comprising:

a frame;

a pair of drive disks rotatably supported by the frame around a central axial line in a mutually opposing relationship;

a pair of actuators supported by the frame for individually rotatively actuating the drive disks;

a plurality of drive rollers arranged along an outer periphery of each drive disk at a regular interval and each having a rotational center line so as to be rotatable along a plane which is neither parallel nor perpendicular to the central axial line;

an annular main wheel disposed approximately coaxially with respect to the central axial line and engaged by the drive rollers of the drive disks, the main wheel comprising an annular member comprising a resilient material for providing resiliency to the annular member and a plurality of driven rollers supported along the annular member so as to be rotatable around a tangential line of the annular member; and

a pressure member acting upon the main wheel such that the main wheel is engaged by the drive rollers at least at a pair of diametrically opposing positions thereof.

8. A vehicle using a frictional drive device as defined in claim 7 .