Bicycle frame structure having a drop-out

1. A bicycle frame structure having a drop-out, the bicycle frame structure comprising:

a fixing bracket having a rail groove formed in a frontward and rearward direction and fixed to one side of the frame;

a movement member mounted to the fixing bracket to be movable forward and backward along the rail groove;

a drop plate fixed to the movement member and having a drop-out formed therein for fixing a wheel; and

an adjustment bolt screw-engaged by penetrating one side of the movement member, wherein a front end of adjustment bolt is supported by a fixing support formed in the fixing bracket, and wherein the movement member is moved along the rail groove according to rotation of the adjustment bolt,

wherein a protrusion is integrally formed in the fixing bracket, the protrusion fixed to the frame by being inserted into one side of the frame.

2. The bicycle frame structure of claim 1 , wherein a cutout portion is formed along a diameter direction in one side of the frame, and wherein the protrusion is inserted into the cutout.

3. The bicycle frame structure of claim 2 , wherein the frame comprises a seat stay and a chain stay, and wherein the cutout portion is formed in a portion where the seat stay and the chain stay meet.

4. The bicycle frame structure of claim 1 , further comprising a connection pin that connects the movement member and the drop plate to each other by penetrating the rail groove.

5. The bicycle frame structure of claim 1 , wherein a quick release (QR) axle or a thru-axle that is disposed at a central axis of rotation of a rear wheel or a front wheel is disposed in the drop-out.

6. A bicycle frame structure having a drop-out, the bicycle frame structure comprising:

a fixing bracket having a rail groove formed in a frontward and rearward direction and fixed to one side of the frame;

a movement member mounted to the fixing bracket to be movable forward and backward along the rail groove;

a drop plate fixed to the movement member and having a drop-out formed therein for fixing a wheel; and

an adjustment bolt screw-engaged by penetrating one side of the movement member, wherein a front end of adjustment bolt is supported by a fixing support formed in the fixing bracket, and wherein the movement member is moved along the rail groove according to rotation of the adjustment bolt,

wherein the frame comprises a right panel and a left panel that are press-molded, and wherein the right panel and the left panel are bonded to each other such that a hollow pipe structure is formed.

7. A bicycle frame structure having a drop-out, the bicycle frame structure comprising:

a fixing bracket having a rail groove formed in a frontward and rearward direction and fixed to one side of the frame;

a movement member mounted to the fixing bracket to be movable forward and backward along the rail groove;

a drop plate fixed to the movement member and having a drop-out formed therein for fixing a wheel; and

an adjustment bolt screw-engaged by penetrating one side of the movement member, wherein a front end of adjustment bolt is supported by a fixing support formed in the fixing bracket, and wherein the movement member is moved along the rail groove according to rotation of the adjustment bolt,

wherein a screw through-hole is integrally formed in a front lower end of the movement member, and wherein the adjustment bolt is screw-engaged to the screw through-hole.

8. The bicycle frame structure of claim 1 , wherein the fixing support and the protrusion are integrally connected with each other.

9. The bicycle frame structure of claim 1 , wherein fixing bolt holes are provided in the fixing bracket for coupling with the frame.