Cap tip assembly for spot welding

1 . A cap tip assembly for spot welding, which is mounted on at least one of electrode rods of a fixed electrode and a movable electrode of a spot welding apparatus and is configured to spot-weld a first base material in which a flange is formed and a second base material overlapping the flange in a vertical direction,

the cap tip assembly for spot welding comprising a tip body provided in a shape of a rectangular block in which a round-shaped welding section is formed on a front side of a top surface,

wherein the tip body comprises a non-welding section extending in a front-rear direction from the welding section to a rear side of the top surface,

wherein the welding section comprises a base metal contact surface of a predetermined curvature, and a virtual welding start line formed in a direction normal to the base material contact surface,

wherein the base material contact surface comprises melt diffusion sections formed on both front and rear portions based on the virtual welding start line.

2 . The cap tip assembly for spot welding of claim 1 , wherein the non-welding section comprises a base material non-contact surface having a greater curvature than that of the base material contact surface.

3 . The cap tip assembly for spot welding of claim 2 , wherein the tip body comprises round sections extending from the base material contact surface and the base material non-contact surface to both lateral sides, respectively.

4 . The cap tip assembly for spot welding of claim 2 , wherein a radius of the base material contact surface is greater than a radius of the base material non-contact surface.

5 . A cap tip assembly for spot welding configured to spot-weld a first base material in which a flange is formed and a second base material overlapping the flange in a vertical direction, comprising:

a tip body provided in a shape of a rectangular block in which a round-shaped welding section is formed on a front side of a top surface; and

a collet member coupled to the tip body to guide a conductive tape to the welding section,

wherein the tip body comprises a non-welding section extending along a front-rear direction from the welding section to the rear side of the top surface,

wherein the welding section comprises a base material contact surface of a predetermined curvature, and a virtual welding start line formed in a direction normal to the base material contact surface, and

wherein the base material contact surface comprises melt diffusion sections formed on both front and rear portions based on the virtual welding start line.

6 . The cap tip assembly for spot welding of claim 5 , wherein the non-welding section has a greater curvature than the welding section.

7 . The cap tip assembly for spot welding of claim 6 , wherein the non-welding section comprises a base material non-contact surface having a greater curvature than that of the base material contact surface.

8 . The cap tip assembly for spot welding of claim 6 , wherein the collet member comprises:

a rectangular collet body including both side walls corresponding to both lateral sides of the tip body, respectively, and opened in the front-rear direction and the vertical direction;

a first tape transport track integrally connected to front upper parts of the both sidewalls to correspond to the welding section; and

a second tape transport track integrally connected to rear upper parts of the both sidewalls to correspond to the non-welding section.

9 . The cap tip assembly for spot welding of claim 8 , wherein the collet member further comprises:

first chamfered portions formed at the front upper parts of the both sidewalls to be lower than the uppermost end of the first tape transport track; and

second chamfered portions formed at the rear upper parts of the both sidewalls to be lower than the uppermost end of the second tape transport track.

10 . The cap tip assembly for spot welding of claim 9 , wherein the first tape transport track comprises a first support surface for supporting a front surface of the tip body, and a first track surface having a round shape for supporting the conductive tape, and

the second tape transport track comprises a second support surface for supporting a rear surface of the tip body, and a second track surface having a round shape for supporting the conductive tape.

11 . The cap tip assembly for spot welding of claim 10 , wherein each of the first chamfered portion and the second chamfered portion comprises a guide surface supporting each of both edge ends of the conductive tape transported along the first track surface and the second track surface.

12 . The cap tip assembly for spot welding of claim 9 , wherein the first chamfered portion comprises:

a first chamfered surface formed at a position lower than the uppermost end of the first tape transport track; and

a second chamfered surface obliquely extending from the first chamfered surface to the both sidewalls.

13 . The cap tip assembly for spot welding of claim 12 , wherein the second chamfered portion comprises:

a third chamfered surface formed at a position lower than the uppermost end of the second tape transport track; and

a fourth chamfered surface obliquely extending from the third chamfered surface to the both sidewalls.

14 . The cap tip assembly for spot welding of claim 8 , wherein the tip body comprises:

a first support step formed in an upper portion of a front surface to support the first tape transport track; and

a second support step formed in an upper portion of a rear surface to support the second tape transport track.

15 . The cap tip assembly for spot welding of claim 8 , wherein the collet body comprises positioning protrusions formed on the both sidewalls, respectively, and

wherein grooves engageable with the positioning protrusions are formed in the tip body.

16 . The cap tip assembly for spot welding of claim 8 , wherein the collet member comprises triangular rib-shaped reference protrusions integrally formed on upper ends of both sidewalls of the collet body.