JPH03155471A - Arc stud welding machine - Google Patents

Abstract

PURPOSE:To use arc shielding split bodies many times by holding the arc shielding split bodies for arc stud welding by holding and pressing these at the inside and outside to form arc shielding. CONSTITUTION:An arc stud welding machine 22 using arc shielding (ferrule) 2 is provided with arc shielding holding parts 44 to hold the arc shielding split bodies 4 in an almost semicircular cylindrical shape. The arc shielding holding parts 44 are held by an inside holding part 60 and an outside holding part 64 to abut on the inside surfaces and the outside surfaces of the arc shielding split bodies 4 and a pressing means 70 to press these holding parts 60 and 64 toward the arc shielding split bodies 4 at the almost center in the circumferential direction thereof. By this method, thermal stress at the time of welding can be reduced and the arc shielding split bodies can be used many times.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an arc stud welding machine comprising an arc shield holding portion that holds a substantially semi-cylindrical arc shield segment.

(Prior art) In arc stud welding, a substantially cylindrical welding auxiliary material called an arc shield (ferrule) has traditionally been used to insert molten metal into the mold and block outside air from the welding area. ing.

Conventionally, such arc shields are made of ceramics, for example, and these conventional ceramic arc shields are damaged by thermal shock (over 1,300°C) during welding and cannot be reused. It is crushed with a hammer, etc. and removed from the weld.

In this way, conventional ceramic arc shields are required for each stud, and are consumable items that cannot be reused.They are also attached to each stud and must be crushed and removed after welding. There is a problem.

In order to solve this problem, for example, Japanese Patent Application Laid-Open No. 59-1413
As disclosed in Japanese Patent No. 79 and Japanese Utility Model Application Publication No. 60-181269, attempts have been made to realize multiple use of the arc shield by forming the arc shield from a material with excellent thermal shock resistance and making it a divided body. Attempts are being made to do so.

(Problem to be Solved by the Invention) By the way, when it is attempted to realize the repeated use of the arc shield many times by forming the above-mentioned arc shield with a material with excellent thermal shock resistance and making it into a divided body, for example, if the arc shield is is made of ceramic with excellent thermal shock resistance, the welding machine is provided with a pair of arc shield holding parts, and each arc shield holding part holds each approximately semi-cylindrical arc shield division body divided into two, The above-mentioned holding parts are brought close together to form a cylindrical arc shield with both arc shield division bodies, then arc stud welding is performed, and after welding is completed, the above-mentioned both holding parts are separated, thereby forming both arc shield division bodies. It is conceivable to remove the arc shield from the welded stud at a distance.

Further, it is considered that the arc shield division body is held by the arc shield holding part by, for example, holding the approximately semi-cylindrical arc shield division body between the same approximately semi-cylindrical inner clamping part and outer clamping part. It will be done.

However, in the case of the above configuration, the arc shield division body is made of ceramics and has an extremely low coefficient of thermal expansion as described above, while the arc shield holding part including the above-mentioned inner and outer clamping parts is usually made of metal. Therefore, if the arc shield segments are simply held between arc shield holding parts with different coefficients of thermal expansion, thermal stress due to the difference in coefficient of thermal expansion due to the high temperature during welding will occur. acts on the arc shield division body,
This may cause damage to the arc shield segment.

In view of the above circumstances, it is an object of the present invention to provide arc stud welding which can sufficiently reduce the thermal stress acting on the arc shield segment due to the difference in the coefficient of thermal expansion and thereby maintain the arc shield segment well. The aim is to provide the opportunity.

(Means for Solving the Problems) In order to achieve the above object, an arc stud welding machine according to the present invention is provided with an arc stud welding machine including an arc shield holding part that holds a substantially semi-cylindrical arc shield division body. The arc shield holding part includes a semi-cylindrical inner clamping part that abuts on the inner surface of the arc shield divided body, and two quarter cylindrical pieces that abut on the outer surface of the arc shield divided body. and a suppressing means for pressing each of the outer clamping parts toward the arc shield divided body at a substantially central position in the circumferential direction of each of the outer clamping parts.

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

FIG. 1 is a perspective view showing an arc shield used in an embodiment of the arc stud welding machine according to the present invention. The illustrated arc shield 2 is made up of a combination of two arc shield division bodies 4 made of ceramics with excellent thermal shock resistance.
It is formed into a substantially cylindrical shape. Both divided bodies 4 have the same substantially semi-cylindrical shape, and FIG. 2 is a perspective view of the divided body 4 seen diagonally from above, and FIG. 3 is a perspective view of the divided body 4 seen diagonally from below.

As shown in FIG.
At the same time, the lower surface is brought into contact with the upper surface of the base material 8, and the welded portion (the portion where the lower surface of the stud 1o and the upper surface of the base material 8 are in contact with each other) 12 is disposed in a manner surrounding the welded portion 12, as shown in the figure. Welding is performed at
In step 2, the molten metal generated is poured into a mold.

A plurality of communication grooves 14 with a predetermined opening area are formed on the lower surface of the arc shield 2 to communicate the inside and outside of the arc shield 2 during welding, and the earth wall 16 has a stud insertion hole 18 that is slightly larger than the outer diameter of the stud lO. Further, a cylindrical held portion 20 for holding the arc shield 2 by a welding machine described below is formed.

FIG. 5 is a front view showing an arc stud welding machine that performs arc stud welding using the arc shield 2, which is an embodiment of the present invention, and FIG. 6 is a right side view of the welding machine shown in FIG. be.

The illustrated welding machine 22 includes a base 24 , a pair of levers 30 rotatably supported by two legs 26 fixed to the base 24 via fulcrum pins 28 , and each lever 30 A pair of links 3B, one end of which is rotatably connected to the upper end through a joint pin 32, and the other end of which is rotatably connected through a joint pin 34, and one link 3B.
A handle 38 is fixed to the one end of the link 38 and extends in the left-right and lateral directions (in the direction of arrow A in FIG. 5), and a joint pin 34 connecting the other ends of both links 36 is inserted and extends in the vertical direction (
An elongated hole member 42 having an elongated hole 40 extending in the direction of arrow B in FIG. The welding gun 48 is attached to a pair of upright rods 46.

The lever 30 can be opened and closed as shown by the broken line in the figure, and the lever 30 is opened and closed by rotating the handle 38 in the vertical direction. Further, a chuck 50 for holding the head of the stud 10 is provided at the lower end of the welding gun 48. Further, the welding gun 48 is provided with a handle 5B having a welding switch 54.

Each of the arc shield holding parts 44 holds one of the arc shield divided bodies 4, and includes a holding part main body 82 having an inner holding part 60 and an outer holding part 64. By pressing inward toward the arc shield segment 4, the arc shield segment 4 is held between the outer clamping portion 64 and the inner clamping portion 60.

Further, a through hole 66 is formed in the holding part main body 82,
A small diameter portion 30a formed at the lower end of the lever 30 is passed through the through hole 6B, and a nut 68 is screwed into the lower end of the small diameter portion 30a, thereby attaching the arc shield holding portion 44 to the lever 30. .

Arc stud welding by the welding machine 22 is performed as follows. First, the handle 38 is rotated upward from the position shown by the solid line in FIG. 5 to the position shown by the broken line, thereby opening the two levers 30 to the open state shown by the broken line. The head of the stud 10 is gripped by a chuck 50 provided at. Next, the handle 38 is rotated downward, thereby closing both levers 30 to the original closed state shown by the solid line. In this closed state, the arc seed holding parts 44 provided on each lever 30 are in contact with each other, and the arc shield divided bodies 4 held by each arc shield holding part 44 are also in contact with each other to form a cylindrical arc shield. 2 is formed, and the stud 10 is fitted into the arc shield 2 in the manner shown in FIG. 4 above. Next, from this state, the welding machine 22 is lowered to bring the lower surface of the stud 10 and the lower surface of the arc shield 2 into contact with a predetermined position of the base metal 8, and the switch 54 provided on the handle 5B of the welding gun is pressed to start welding. Do this. After welding is completed, the above handle 38
is rotated upward to open the lever 30, and thereafter arc stud welding is repeated in the same manner.

The opening/closing operation of the two levers 30 by the handle 38 will be described in detail with reference to FIGS. 7 to 9. First, as shown in FIG. 7, when the handle 38 is in a horizontal state, the lever 3o is in a closed state, and when the handle 38 is rotated upward from this state, both links 3o are closed as shown in FIG. The joint pin 34 whose other ends are rotatably connected to each other descends along the elongated hole 40, both links 3G are tilted as shown, and both levers 30 rotate in the downward opening direction about the fulcrum pin 28. It becomes open.

Further, when the handle 38 is turned downward from the state shown in FIG. 9, both levers 30 return to the closed state shown in FIG. 7. Note that FIG. 8 is a sectional view taken along the line ■--■ in FIG. 7.

The welding machine 22 is configured to open and close the lever 30 (arc shield divided body 4) by rotating the handle 38, and therefore the opening and closing operations can be performed very easily and at will. Can be done.

Further, the welding machine 22 is configured to open and close the lever 30 (arc shield divided body 4) within the vertical plane that includes the stud 10, and therefore, the lever 30 can be opened and closed at right angles to the stud 10, for example. Compared to a configuration in which welding is performed in a plane (in a plane parallel to the upper surface of the base material 8), problems such as interference with other studs 10 do not occur when welding a large number of studs 10.

Further, the handle 38 is not only used to open and close the lever 30, but also functions as a handle for stabilizing the welding posture in cooperation with the handle 56 of the welding gun. That is, the handle 56 provided on the welding gun 48 extends in the front-rear direction (in the direction of arrow C in FIG. 6) from the rear surface of the welding gun 48, and the handle 38 is 90'' with respect to the handle 56. By arranging the handle 38 at a right angle to the handle 5B of the welding machine and below it, the handle 56 of the welding machine can be used with the right hand of the welding machine. The welding machine 22 can be held in a well-balanced manner by gripping the handle with the index finger on the switch 54 and gripping the handle 38 with the left hand, making it easier for the welder to maintain a stable welding posture, improving work efficiency and reducing welding defects. It will be done.

Further, the chuck 50 is configured to hold the stud 10 coaxially with the welding gun 48, and the stud lO gripped by the chuck 50 is attached to the two levers 30 to which the arc shield holder 44 is attached. In other words, the center axis of the stud IO and the center axes of the two levers 30 should be located on the same plane (a plane extending in the horizontal and vertical directions) (the lever 30 and the welding gun 48 are arranged). With this configuration, the arc shield 2 is brought into contact with the base metal reliably and evenly, thereby enabling stable welding and improving welding reliability. It will be planned.

Further, in the welding machine 22 described above, the arc shield 2 and the arc shield holding part 44 are divided into two parts, and they are attached to the lower end of the lever 30, and the chuck 5 of the stud 10 is
When attaching the chuck 5 to the chuck 5, open the lever 30 widely.
Since the structure ensures a large space in the vicinity of 0, it is easy to attach the stud 10 to the chuck 50.

Further, as described below, a guide pin 80 is provided on one abutting surface of the arc shield holding portion 44, and a guide hole 82 is provided on the other abutting surface. Proper contact between the shield holding portion 44 and the arc shield divided body 4 is ensured.

Next, the holding of the arc shield divided body 4 by the arc shield holding section 44 will be described in more detail with reference to FIGS. 10 and 11.

Figure 10 is a sectional view taken along the line X-X in Figure 11, and Figure 11 is a cross-sectional view of Figure 1.
This is a cross-sectional view taken along the old line -xi of Figure O, and both figures show the above lever 3.
0 and bring the pair of arc shield division bodies 4 into contact with each other,
It is a figure which shows the state where the cylindrical arc shield 2 is formed by this.

As shown in the figure, each holding part main body 62 is formed with a semi-cylindrical inner clamping part 60 that contacts the inner surface of the semi-cylindrical held part 20 of the arc shield divided body, and the arc shield divided body 4 is The inner surface of the holding part 20 is connected to the inner holding part B.
It is attached to the holding part main body 62 in contact with the outer surface of the
Two outer clamping portions 64 each having a circular arc shape of 0' are disposed,
Each outer clamping part 64 is connected to the center (the cylindrical arc shield when the cylindrical arc shield 2 is formed by abutting the arc shield divided body 4) by a suppression screw 70 which is a suppression member screwed into the holding part main body 62. As a result, the arc shield divided body 4 is held between the inner and outer holding parts 60 and 64.

The pressing of the outer clamping part 64 by the suppressing screw 70 is performed so that the tip of the suppressing screw 70 is pressed toward the center at the central part of the external clamping part 64 (the central part in the 90° arc direction). The suppressing screw 70 is set so as to be in contact with the center portion of the holding screw 64 and to have its axis directed toward the center.

When the cylindrical arc shield 2 is divided into two parts and each arc shield divided body 4 is held, it is held between the semi-cylindrical inner holding part 60 and the two quarter-cylindrical outer holding parts 64 as described above. , and by adopting a configuration in which each outer clamping part B4 is pressed toward the center at the central part, the difference in thermal expansion coefficient between the arc shield divided body 4, the holding part main body 62, and the outer clamping part 64 during welding can be reduced. This is intended to prevent cracking of the arc shield divided body 4 due to the above.

That is, before welding, the inner and outer holding parts 80.134 and the held part 20 of the arc shield divided body are in contact with each other over the entire area, as shown in FIG. 12 which is a plan view. Welding is performed from this state, and when the temperature reaches a high temperature, each part 60, 20.84
expands thermally. In this case, the arc shield divided body 4 is made of ceramics as described above, and the inner and outer holding parts Go,
84 is made of a metal with good thermal conductivity, such as copper, in order to improve heat dissipation. Ceramics hardly expand thermally, but metal expands thermally significantly. Therefore,
If the outer clamping part B4 is also semi-cylindrical, and if the outer clamping part B4 is pressed in the central direction at its circumferential center, the held part 20 of the arc shield divided body will be Only the center part contacts the outer clamping part 64' and receives a force directed toward the center from the central part, and only both ends contact the inner clamping part 60 and receive an outward reaction force from both ends. As can be easily understood from FIG. 13, an extremely large thermal stress (bending moment) acts on the arc shield segment 4, making it susceptible to cracking and breakage.

On the other hand, in the above-mentioned welding machine, the semi-cylindrical outer clamping part 84' is further divided into two into two 1/4 cylindrical outer clamping parts B4, and the circumference of each 174 cylindrical outer clamping part 64 is Since the configuration is such that a pressing force is applied in the central direction in the central direction, the state of action of the force during thermal expansion is as shown in Figure 14, and as can be easily understood from this figure, the arc shield is divided. Thermal stress acting on body 4 (
The bending moment) is much smaller than that in the case shown in FIG. 13, and therefore, the risk of cracking or breakage of the arc shield segment 4 due to the difference in coefficient of thermal expansion is significantly reduced.

A locking screw 72 is screwed into the pressing screw 70, and the outer clamping portion 64 is fitted into and locked into the locking screw 72. As a result, the outer holding part 6 by the above-mentioned suppression screw 70
This is intended to prevent the outer clamping part 64 from falling off from the holding part main body 62 when the pressure of 4 is released.

Further, the locking screw 72 is loosely inserted into the outer holding portion 64 with a predetermined gap, and this and the pressing screw 7
0 (the part that presses the outer clamping part 64) has a substantially conical shape, increasing the degree of freedom of displacement of the outer clamping part 64 with respect to the pressing screw 70, thereby preventing the arc shield from splitting during the thermal expansion. The force acting on the body 4 is reduced.

Also, in order to reduce the force acting on the arc shield divided body 4 during thermal expansion, for example, although not shown, the tip pressing portion of the pressing screw 70 is displaced toward the center using a buffer mechanism consisting of a spring or the like. It may be supported if possible.

Further, as described above, the arc shield holding part 44 (holding part main body 62 and outer clamping part 64) is made of copper or its alloy having high thermal conductivity, and the outer periphery of the arc shield holding part 44 is made of copper or its alloy. 62 are formed, and the high heat generated during welding is efficiently radiated into the air without being stored in the ceramic arc shield, thereby preventing high temperature deterioration of the arc shield. , the lifespan is being extended.

Further, the arc shield holding portion 44 is attached to the stepped portion (small diameter portion 30) of the lever 30 via the holding portion main body 62.
a and the large-diameter portion 30b) and the nut 68 so as to be slidable along the small-diameter portion 30a of a predetermined length, and a spring receiver 76 is fixed to the lever large-diameter portion 30b. A compression spring 78 is provided between the spring receiver 76 and the upper surface of the holding part main body 62, and these constitute a buffer mechanism for the arc shield 2. This buffer mechanism causes no force on the ceramic arc shield 2 during welding. It is possible to stably press it against the base material 8 without applying excessive force. That is, before welding, the lower end of the lever 30 is located above the lower end of the arc shield 2, as shown by the two-dot chain line in FIG. When pressing, press lever 3.
The lower end of the base material 8 contacts the upper surface of the base material 8.

In other words, all of the pressure exerted by the operator that is sufficient to fix the welding machine so that it does not move during welding is transmitted to the base material 8 through these two levers 30, so that the arc shield 2 is always kept at a constant level by the compression spring 78. It has a structure that allows it to be pressed against the base material 8 with a reasonable pressing force.

Further, the entire outer periphery of the arc shield 2 is covered by the arc shield holding portion 44, thereby preventing the arc shield 2 from directly hitting external objects and being damaged or destroyed.

Next, the material of the arc shield 2 will be explained.

The arc shield 2 may be made of any material as long as it has excellent thermal shock resistance and low adhesion to molten metal, but it is preferably made of ceramic containing 20% by weight or more of boron nitride, for example. It can be used for. The arc shield 2 made of ceramics containing 20% by weight or more of boron nitride can sufficiently withstand thermal shock (1400° C. or more) during arc welding and has no adhesion to molten metal, so it can be used in large numbers by the welding machine described above. Can be used repeatedly.

(Effects of the Invention) As described in detail above, the arc stud welding machine according to the present invention has a substantially semi-cylindrical arc shield divided body with a semi-cylindrical inner holding part and two quarter-cylindrical outer parts. Clamp with the clamping part,
The arc shield divided body is held by pressing each 1/4 cylindrical outer holding portion toward the arc shield divided body at a substantially central position in the circumferential direction by the suppressing means. , the thermal stress caused by the difference in coefficient of thermal expansion can be sufficiently reduced, and the arc shield segment can be held well. .

[Brief explanation of the drawing]

1, 2, and 3 are perspective views showing an arc shield used in an embodiment of the arc stud welding machine according to the present invention, and FIG. 4 is a cross-sectional view showing the use state of the arc shield shown in FIG. 1. Figure 5 is a front view showing one embodiment of the arc stud welding machine according to the present invention, Figure 6 is a right side view of the welding machine shown in Figure 5, and Figures 7 and 9 are Figure 5. 8 is a sectional view taken along the line ■-■ in FIG. 7. FIGS. 10 and 11 are details of the arc shield holding part of the welding machine shown in FIG. 5. 10 is a sectional view taken along the line X-X in FIG. 11, FIG. 11 is a sectional view taken along the line Xl-Xl in FIG. FIG. 6 is a plan view for explaining changes in the shield holding state. 2... Arc shield 4... Arc shield divided body 22... Arc stud welding machine 44... Arc shield holding part 60... Inner clamping part 64... Outer clamping part 70... Suppressing means Fig. 1 Fig. 4 Fig. 5 Fig. 1 - Fig. 10 Fig. 1 Fig. 2 Fig. 3 Fig. 4

Claims (1)

[Scope of Claims] An arc stud welding machine comprising an arc shield holding part that holds a substantially semi-cylindrical arc shield divided body, wherein the arc shield holding part is attached to an inner surface of the arc shield divided body. a semi-cylindrical inner clamping part that abuts, two quarter-cylindrical outer clamping parts that contact the outer surface of the arc shield division body, and each of the outer clamping parts at a substantially central position in the circumferential direction. An arc stud welding machine comprising: pressing means for pressing the arc shield divided body.