Folding type bicycle

1. A folding type bicycle comprising:

a front frame provided with a front wheel and a handle;

a center frame provided with pedals and a saddle;

a rear frame provided with a rear wheel;

a hinge device to enable the front frame, the center frame and the rear frame to pivot about one another, to be foldable with respect to one another, the hinge device comprising a front hinge member provided at the front frame, a center hinge member provided at the center frame, and a rear hinge member provided at the rear frame;

a hinge shaft centrally provided at the hinge device;

a front rim provided at the front hinge member, a center rim provided at the center hinge member and a rear rim provided at the rear hinge member; and

a plurality of rolling members fitted in fitting holes in the center hinge member to enable rolling-contact among the front, center and rear rims.

2. The folding type bicycle according to claim 1 , wherein:

each of the front and rear rims comprises rim guides each having an arc shape, and rim protrusions extending from opposite ends of each of the rim guides, respectively; and

each of the rolling members comprises a cylinder fitted in a fitting hole formed at the center frame, and rollers respectively fitted around opposite ends of the cylinder, to rotatably contact corresponding ones of the rim guides of the front and rear rims.

3. The folding type bicycle according to claim 2 , wherein each of the rim guides and the rim protrusions thereof define a sector shape, to limit movement of a corresponding one of the rolling members.

4. The folding type bicycle according to claim 1 , wherein:

the center rim comprises rim guides each having an arc shape, and rim protrusions extending from opposite ends of each of the rim guides, respectively; and

each of the rolling members comprises a cylinder fitted in a fitting hole formed at a corresponding one of the front and rear frames, and a roller fitted around an end of the cylinder, to rotatably contact a corresponding one of the rim guides of the corresponding rim.

5. The folding type bicycle according to claim 4 , wherein each of the rim guides and the rim protrusions thereof define a sector shape, to limit movement of a corresponding one of the rolling members.

6. The folding type bicycle according to claim 1 , wherein the hinge device further comprises:

an operating lever to pivot about the hinge shaft; and

a spacing member to adjust spacing among the front, center and rear frames in accordance with pivoting of the operating lever.

7. The folding type bicycle according to claim 6 , wherein:

the spacing member comprises a rotating cam and a fixed cam, which have facing cam surfaces, respectively; and

the rotating cam is provided at the rear hinge member, to be fixed to the rear hinge member, and the fixed cam is provided at the center hinge member, to be fixed to the center hinge member, such that spacing between the cam surfaces is adjusted in accordance with the pivoting of the operating lever.

8. The folding type bicycle according to claim 7 , further comprising:

a battery, a motor, and an electronic control unit,

wherein the electronic control unit and the battery are received in one of the front, center and rear frames, and

the motor is operatively connected to the rear wheel.