JPH0233477B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in a stud welding method and apparatus for welding studs without contaminating the workpiece by directing air around the welding area through a spark shield. .

The broad technical idea of supplying fluid or gas through a spark shield or ferrule around a stud to be welded to a workpiece is well known in this field, for example, as disclosed in U.S. Pat.
No. 2727123, No. 2790066, No. 3096429, No.
It is disclosed in No. 3363084, No. 3736401, and Japanese Patent Application Laid-open No. 52-56045. In these known patents, stud welding equipment is used to supply inert gas around the alumina studs during the welding operation or to supply air around the studs to assist in welding through galvanized steel sheets. It was used.

When a stud is welded to a workpiece by jump arc stud welding techniques, it is common for the workpiece to become contaminated around the welded end of the stud. This also occurs, for example, with finishing studs whose later clips are welded to the body of a motor vehicle for the attachment of finishing strips. After the studs are welded, but before any clips or decorative pieces are applied, the vehicle body is provided with a protective coating, such as a primer or subsequent decorative paint. If dirt deposits around welded studs are not removed from the workpiece or vehicle body, the protective coating will not be properly applied and will separate from the surface. The conventional technology described in the above-mentioned gazette only allows fluid to flow through the welding location.
It was still insufficient to completely remove the adhesion of dirt.

SUMMARY OF THE INVENTION An object of the present invention is to provide a stud welding method and apparatus which eliminates the drawbacks of the prior art as described above.

The invention is characterized in that, during the welding cycle, a plurality of independent air flows are created uniformly around the welding point where the stud is welded at an angle of less than 90° to the workpiece.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Referring to the drawings, and in particular to FIG. 1, there is shown a stud welding apparatus according to the present invention, which includes a stud welding tool 10 and a spark shield 42. As shown in FIG. The stud welding tool 10 has a tool body 14. The spark shield 42 is attached to a welding table 28, which is attached to the tool body 14 by a single support leg 26 located at the front of the tool itself. This stud welding apparatus is used to weld the stud 20 to the surface of the workpiece (base body) 11 to be welded by arc welding. The spark shield 42 has a cylindrical body 44, as shown in FIGS. 4, 7, and 8, and the stud is a chuck 18 disposed within the cylindrical body.
(see Figure 4). The chuck 18 has rearwardly extending legs 16 which extend into the tool body 14, as shown in FIGS. The tool body 14 is provided with a stud welding means for pressing the stud against the workpiece, and an advancing/retracting means for advancing the stud toward the workpiece or retracting it away from the workpiece. It is being The stud pressure welding means consists of a spring (not shown) that presses the stud 20 against the workpiece 11, and the advancing/retracting means resists this spring and retracts the stud from the workpiece 11 at a predetermined distance, and It consists of a solenoid coil (not shown) that releases its operation and directs the stud toward the workpiece. This solenoid coil is connected to the chuck leg 16. The stud 20 is constantly pressed by a spring towards the workpiece via an adjusting stop 19. When the stud is retracted from the workpiece by the solenoid coil at a predetermined distance, a pilot arc jumps between the stud end and the workpiece, then the main welding arc is applied to the pilot arc, and then The stud is driven against the workpiece by the spring, and the stud is welded to the workpiece. This is performed by the power supply/control device 12, but since such an operation is well known, further detailed explanation will be omitted. still,
Welding tools of this type may be of the type disclosed in U.S. Pat. No. 3,525,846 and
It is desirable to use a storage type power source such as that disclosed in the specification of No. 3136880.

Power supply and control unit 12 provides power to the pilot arc, main welding arc, and solenoid coils within tool body 14 as described above. As mentioned above, the solenoid coil retracts the stud against the force of the spring upon activation. Stud 20, as shown in FIG. 4, consists of a head 22 held by chuck 18 and a shaft 24 extending forwardly from the head. The tip of this shaft is welded to the surface of the workpiece to be welded. This stud is inserted into the chuck 18 by hand. For loading studs into chucks, see U.S. Pat.
Disclosed in No. 3489878. In addition, the object to be welded 11
For example, the stud 20 can be a decorative stud welded to the body of a car.

The weld table 28 includes an aperture 30 and a flange 32 extending inwardly around the chuck leg 16. A passage 34 for air supply is formed in the welding table and communicates with the opening 30. The welding table has a fitting 36 connected to a pipe 38. Air is supplied to the welding table through tube 38 from a fluid source or control module 40 (FIG. 1). Clean working air may also be supplied to the control module 40, but this air is typically at a pressure of about 80 psw. The control module 40 has a valve (not shown) controlled by the power supply and control device 12 through which air is supplied to the welding table 28 during the welding cycle.
supply to.

The spark shield 42 is inserted into the opening 30 of the welding table at one end, the rear end in the illustrated case. In this spark shield 42, the stud 20 is the workpiece 1 to be welded.
1, the stud 20 is positioned so that the tip of the shaft 24 extends slightly beyond the front end of the spark shield, as shown in FIG. The cylindrical body 44 of this spark shield has a rear flange 46 that abuts the flange 32 of the welding table 28.
It is equipped with An annular groove 48 is formed in the cylindrical body 44 adjacent the flange 46 and communicates with the passageway 34 of the weld table 28. Cylindrical body 44
includes an outer cylindrical portion 50 whose outer periphery is bulged adjacent to the annular groove 48 and a shoulder portion 52 adjacent to the outer cylindrical portion and adjacent to the annular groove 48. A sealing ring 54 is also fitted over the outer periphery of the spark shield adjacent shoulder 52 (FIGS. 2 and 6).
(see figure). The sealing ring 54 is the spark shield 4
2 and an annular groove 56 containing an O-ring 58 for sealing the opening 30. The front plate 59 comes into contact with the front surface of the sealing ring 54, and the spark shield 4
2 is locked on a welding table 28. A plurality of air passages are provided on the outer surface of the cylinder 44. The passage includes a plurality of first passages 6 extending axially around the outer circumference of the cylindrical body and spaced apart circumferentially.
0 and a second passage 74 communicating with this first passage.
It consists of. A first passageway extends from annular groove 48 past shoulder 52 and barrel 50 to a forward shoulder 62 at the forward end of spark shield 42 .
These longitudinally extending first passages 60 are enclosed by a sleeve 64 which fits around the outer circumference of the cylinder and extends from the outer cylindrical portion 50 of the cylinder 4 to the forward shoulder 62. The front end of the cylindrical body 44 is provided with a plurality of rectangular radially extending notches 66 that are connected to the outer surface of the cylindrical body 44 and the front inner surface 68 of the cylindrical body 44 .
It communicates with Spark shield 42 is preferably made from copper, and the front inner surface 68 is highly polished to minimize spatter build-up. A larger diameter inner surface 70 is positioned rearward of the forward inner surface 68 and offset from the shoulder 72 .

A second passage 74 is provided at the front end of the cylindrical body 44 . The air outlet of the passageway, i.e. the outlet of the second passageway, is adapted to direct the air obliquely around the weld location. a first passageway 60 extending in the longitudinal direction;
One second passage 74 is provided for each. Each of these second passages 74 has an outer end 76 that communicates with one of the first passages 60 and an inner end 78 that terminates in an inner surface 68 of the spark shield. The second passage 74 is connected to the shaft 24 of the stud.
The weld is positioned at an angle with respect to the surface to be welded so as to direct the air flow around the location where the end of the weld is to be welded at an acute angle, i.e., at an angle less than 90 degrees, to the weld. This angled air direction causes the air flow to create a swirling effect near the weld area, which prevents contamination during the welding cycle. Note that air is directed around the weld. Care must be taken that if the air stream is directed directly at the point where the stud is to be welded, this air stream will extinguish the pilot arc and thus the main welding arc will no longer be applied to the pilot arc.

The axis of each second passage 74 is disposed at an angle of about 20 degrees, preferably 18 degrees, with respect to the surface of the workpiece, ie, a vertical plane as shown. Air pressure is 80
When ugly, 1 to 10 passages 74, preferably 8 passages are preferred, and the diameter is 0.05
cm to 0.15 cm, preferably 0.1 cm. When the inner surface 68 has a diameter of about 1.12 cm, the inner end 78 of the second passageway 74 is preferably between 0.25 cm and 0.45 cm from the cylindrical body 44 of the spark shield.
It is best if it ends at about 0.31cm. In any case, the location of the passage must be such that the passage directs the air flow beyond the end of the chuck 18 and at a very narrow angle to the workpiece to avoid turbulence. Must be. Of course, the angle, length, and diameter of the second passage 74 can be varied depending on, for example, the size of the stud or spark shield and the air pressure.

According to the present invention, as described above, the air is directed at an angle around the welding part, which causes a swirling action, but the turbulent flow is prevented, so that the welding part can be prevented from getting dirty without extinguishing the arc. There is a practical benefit of being able to prevent this from happening.

Note that the present invention is not limited to the above embodiments.

[Brief explanation of drawings]

FIG. 1 is an overall view showing a stud welding apparatus according to the present invention, partially in elevation and partially in perspective, and FIG.
Figure 3 is an enlarged view of the welding table and spark shield of the welding equipment shown in Figure 2, partially in elevation and partially in section; Figure 3 is a front view showing the welding table and spark shield in Figure 2 in elevation; Figure 4 is A cross-sectional view of the spark shield and the chuck along the line 4-4 in Fig. 5, a cross-sectional view taken along the line 5-5 in Fig. 2, and Fig. 6 a cross-sectional view taken along the line 6-6 in Fig. 2. FIG. 7 is a side view of the cylindrical body, FIG. 8 is a sectional view taken along line 8--8 in FIG. 7, and FIG. 9 is a sectional view of the sealing ring. 10... Welding tool, 11... Work to be welded, 14...
Tool body, 18...Chuck, 20...Stud, 28...Welding table, 30...Opening, 42...Spark shield, 44...Cylindrical body, 48...Annular groove, 54...Sealing ring, 60... ...first passage, 66...notch, 74...second passage.

Claims (1)

[Scope of Claims] 1. A stud welding method in which a stud is held at a distance from a workpiece, a welding arc is generated between the stud and the workpiece, and the stud is pressed toward the workpiece. During the welding cycle, the stud uniformly directs multiple independent air streams around the welding point at an angle of less than 90° to the surface to be welded, creating a non-turbulent swirl of air around the welding point. A stud welding method characterized in that dirt is substantially prevented from adhering to the surface to be welded around the stud. 2. A stud welding device that substantially prevents dirt from adhering to the surface to be welded around the stud, which has a stud pressure welding means for pressing the stud against the object to be welded, and the stud and the object to be welded. means for generating a welding arc between the
means for advancing and retracting the stud relative to the workpiece; a spark shield that is attached to the stud welding tool to surround the stud and has a plurality of passages through which air passes; and a fluid source connected to the passages. The passage is provided in the peripheral wall of the spark shield so as to direct air around the welding point between the stud and the object to be welded, and the air outlet of the passage is arranged so that the air is supplied at an angle to the surface to be welded. A stud welding device characterized in that the spark shield is provided at an angle of less than 90° with respect to the surface to be welded so that the stud welding device has a spark shield. 3. A stud welding device that substantially prevents dirt from adhering to the surface of the workpiece around the stud, which has a stud pressure welding means for pressing the stud against the workpiece, and a stud and the workpiece. A means for generating a welding arc between the stud and the workpiece, a means for advancing and retracting the stud with respect to the workpiece, a spark shield attached to the stud welding tool and having a plurality of air passages, and a spark shield. a plurality of radially extending notches provided at one end and a fluid source connected to one end of the passageway, the passageway directing air around the welding point between the stud and the workpiece; The air outlet of the passage is provided on the peripheral wall of the spark shield so that the air outlet has an angle of less than 90° with respect to the surface to be welded so that the air is supplied at an angle to the surface to be welded. A stud welding device comprising: