Frame structure of vehicle

1. A frame structure of a vehicle comprising:

a first member composed of a metal plate; and

a second member composed of a metal plate having a thickness thinner than that of the first member, the second member integrally connected to the first member by welding,

wherein a connection portion between the first member and the second member has an inclined surface, which is configured to obliquely connect an upper surface of the first member and an upper surface of the second member such that the upper surface of the second member is positioned to be lowered than the upper surface of the first member in a gradual manner,

wherein the first member and the second member have bottom surfaces, respectively, leveled to each other,

wherein the frame structure further includes a panel member configured to be attached to the bottom surface of the first member and the bottom surface of the second member, and

wherein the panel member and the connection portion are spaced apart from each other and the first member and the second member are spaced apart from each other, such that a paint is disposed in a space between the first member, the second member, and the panel member.

2. The frame structure of the vehicle of claim 1 , wherein the connection portion is configured to connect an end of the first member and a portion of the second member.

3. The frame structure of the vehicle of claim 1 , wherein the inclined surface has a height which varies between a height of the first member and a height of the second member.

4. The frame structure of the vehicle of claim 1 , wherein the inclined surface is configured to connect the upper surface of the first member and the upper surface of the second member.

5. The frame structure of the vehicle of claim 1 , wherein the first member is one of a quadrant reinforce frame and a B pillar frame configuring a door frame of a door assembly, and

wherein the second member is one of a roof frame or an inner belt rail bonded to the quadrant reinforce frame or the B pillar frame.

6. The frame structure of the vehicle of claim 1 , wherein the first member and the second member are integrally connected to each other by a tailor welded blank (TWB) welding.

7. A frame structure of a vehicle comprising:

a first member composed of a metal plate;

a second member composed of a metal plate having a thickness thinner than that of the first member, the second member integrally connected to the first member by welding; and

a glass run disposed in a portion in which the first member and the second member are connected in a stepwise manner,

wherein the first member and the second member have bottom surfaces, respectively, leveled to each other, and

wherein the frame structure further includes a panel member configured to be attached to the bottom surface of the first member and the bottom surface of the second member.

8. The frame structure of the vehicle of claim 7 , further comprising a protrusion protruding from an outer surface of the glass run and extending toward a step between the first member and the second member.

9. The frame structure of the vehicle of claim 8 , wherein the glass run has a hole therein.

10. The frame structure of the vehicle of claim 7 , wherein the first member is one of a quadrant reinforce frame and a B pillar frame configuring a door frame of the vehicle, and

wherein the second member is one of a roof frame or an inner belt rail bonded to the quadrant reinforce frame or the B pillar frame.

11. A method of manufacturing a frame structure of a vehicle, the method comprising:

forming a first member composed of a metal plate; and

forming a second member composed of a metal plate having a thickness thinner than that of the first member, the second member integrally connected to the first member by welding,

wherein a connection portion between the first member and the second member has an inclined surface, which is configured to obliquely connect an upper surface of the first member and an upper surface of the second member such that the upper surface of the second member is positioned to be lowered than the upper surface of the first member in a gradual manner, and

wherein the inclined surface is configured to be integrally connected with the upper surface of the first member and the upper surface of the second member in a way that the upper surface of the first member is higher than the upper surface of the second member,

wherein the connection portion is integrally attached to an end of the first member contacting an end of the second member.

12. The method of claim 11 , wherein the upper surface of the first member is disposed to be higher than the upper surface of the second member by a press processing.

13. The method of claim 11 , wherein the connection portion has the inclined surface formed by disposing and welding a bottom surface of the first member and a bottom surface of the second member to be leveled, and then obliquely removing an end portion of the first member.

14. The method of claim 13 , wherein a portion of the first member contacting the second member includes the inclined surface formed by grinding.

15. The method of claim 11 , wherein the connection portion has the inclined surface formed by disposing and welding a bottom surface of the first member and a bottom surface of the second member to be leveled, forming a welding bead on a bonded portion between the first member and the second member, and obliquely removing a part of the welding bead.

16. The method of claim 15 , wherein the connection portion is integrally attached to the upper surface of the second member and has the inclined surface by grinding the welding bead.

17. The method of claim 15 , wherein the connection portion is integrally attached to the first member and the second member by soldering the welding bead.

18. The method of claim 11 , wherein the first member and the second member are configured to be integrally connected to each other by a tailor welded blank (TWB) welding.