JP2687024B2 - Arc stud welding machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an arc stud welder including an arc shield holding portion that holds a substantially semi-cylindrical arc shield divided body.

(Prior Art) In arc stud welding, a welding auxiliary material called a substantially cylindrical arc shield (ferrule) has conventionally been used to mold molten metal and shield the weld from the outside air. ing.

As such an arc shield, for example, a ceramics shield has been conventionally used, and this conventional ceramics arc shield has a thermal shock (1,300 ° C or higher) during welding.
It was damaged due to damage and cannot be reused. Therefore, after welding, it is crushed with a hammer etc. and removed from the weld.

In this way, the conventional ceramic arc shield
One consumable item is required for each stud and cannot be reused, and it has a problem that it must be attached to each stud and must be crushed and removed after welding.

In order to solve such a problem, for example, as disclosed in JP-A-59-141379 and JP-A-60-181269, the arc shield is formed of a material having excellent thermal shock resistance and is divided into a divided body. By doing so, an attempt has been made to realize the multiple use of the arc shield.

(Problems to be Solved by the Invention) By the way, when the arc shield is formed of a material having excellent thermal shock resistance, and when it is intended to realize repeated use of the arc shield by forming a divided body,
For example, the arc shield is made of ceramics having excellent thermal shock resistance, the welding machine is provided with a pair of arc shield holding parts, and each arc shield holding part is divided into two substantially semi-cylindrical arc shield divided bodies. Hold the two holding parts close to each other to form a cylindrical arc shield with the two arc shield divided bodies, and then perform arc stud welding, and after the welding is completed, separate the two holding parts, thereby both arc shields. It is conceivable to separate the dividers and remove the arc shield from the welded studs.

Further, the holding of the arc shield divided body by the arc shield holding portion is considered to be carried out, for example, by holding the substantially semi-cylindrical arc shield divided body by the same substantially semi-cylindrical inner holding portion and outer holding portion. To be

However, in the case of the above configuration, it is considered that the arc shield divided body is made of ceramics and has a very low coefficient of thermal expansion as described above, while the arc shield holding portion including the inner and outer holding portions is usually made of metal. Therefore, the thermal expansion coefficient is high, so if the arc shield holding parts with different thermal expansion coefficients are simply sandwiched, the thermal stress caused by the difference in the thermal expansion coefficient due to the high temperature during welding is high. Acts on the arc shield split, which may damage the arc shield split.

In view of the above circumstances, an object of the present invention is to sufficiently reduce the thermal stress acting on the arc shield divided body due to the difference in the coefficient of thermal expansion, and thus to hold the arc shield divided body in good condition. To provide a machine.

(Means for Solving the Problem) In order to achieve the above object, an arc stud welding machine according to the present invention is provided with an arc shield holding portion for holding a substantially semi-cylindrical arc shield divided body. And the arc shield holding part is a semi-cylindrical inner holding part that comes into contact with the inner surface of the arc shield divided body, and two 1/4 cylindrical shapes that come into contact with the outer surface of the arc shield divided body. And an pushing means for pushing each of the outer holding portions toward the arc shield divided body at a substantially central position in the circumferential direction thereof.

(Embodiment) Hereinafter, an embodiment 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 formed by combining two arc shield divided bodies 4 made of ceramics having excellent thermal shock resistance, and 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 as seen obliquely from above and FIG. 3 is a perspective view of the divided body 4 as seen obliquely from below.

As shown in FIG. 4, when the stud 10 is welded to the base material (material to be welded) 8, the arc shield 2 has the stud 10
And the lower surface is brought into contact with the upper surface of the base material 8 so as to surround the welded portion (the portion where the lower surface of the stud 10 and the upper surface of the base material 8 are in contact) 12 and is arranged in the state shown in the drawing. Welding is performed, and the arc shield 2 shields the welded portion 12 from the outside air during welding and molds the molten metal generated in the welded portion 12.

A plurality of communication grooves 14 having a predetermined opening area for communicating the inside and outside of the arc shield 2 during welding are formed on the lower surface of the arc shield 2, and a stud insertion hole 18 slightly larger than the outer diameter of the stud 10 is formed on the upper wall 16. A cylindrical held portion 20 is formed for holding the arc shield 2 in a welding machine described below.

FIG. 5 is a front view showing an arc stud welding machine for carrying out arc stud welding using the arc shield 2 according to an embodiment of the present invention, and FIG. 6 is a right side view of the welding machine shown in FIG. is there.

The welding machine 22 shown in the drawing has a base portion 24 and 2 fixed to the base portion 24.
A pair of levers 30 rotatably supported on the leg portions 26 of the book via fulcrum pins 28, one end rotatably connected to the upper ends of the levers 30 via joint pins 32, and the other end. Comrades rotatably connected via joint pin 34 1
A pair of links 36 and a handle 38 fixed to the one end of one of the links 36 and extending in the lateral direction (the direction of arrow A in FIG. 5).
And a long hole member 42 fixed to the base 24 having a long hole 40 through which a joint pin 34 for connecting the other ends of both links 36 is inserted and extending in the vertical direction (direction of arrow B in FIG. 5). ,
It comprises an arc shield holding portion 44 provided at the lower end of each lever 30 and a welding gun 48 attached to a pair of rods 46 standingly provided on the base portion 24.

The lever 30 can be opened and closed as indicated by a broken line in the figure, and the opening and closing of the lever 30 is performed by rotating the handle 38 in the vertical direction. Also, the above welding gun 48
A chuck 50 for holding the head of the stud 10 is provided at the lower end of the chuck. Further, the welding gun 48 is provided with a handle 56 having a welding switch 54.

Each of the arc shield holding portions 44 holds the one arc shield divided body 4, and includes a holding portion main body 62 having an inner holding portion 60 and an outer holding portion 64, and the outer holding portion 64. By pressing the arc shield divided body 4 inwardly, the outer shield holding portion 64 and the inner holding portion 60 hold the arc shield divided body 4.

Further, a through hole 66 is formed in the holding portion main body 62, and the small diameter portion 30 formed at the lower end of the lever 30 is formed in the through hole 66.
a is penetrated, and a nut 68 is screwed to the lower end of the small diameter portion 30a,
Therefore, the arc shield holding portion 44 is attached to the lever 30.

The arc stud welding by the welding machine 22 is performed as follows. First, the handle 38 is pivoted upward from the position shown by the solid line in FIG. 5 to the position shown by the broken line, whereby the two levers 30 are opened to the open state shown by the broken line, and then the tip of the welding gun. Chuck provided on 50
Hold the head of stud 10 on. Then the above handle
38 is rotated downwards, thereby closing both levers 30 to the original closed state shown by the solid line. In this closed state,
The arc seed holders 44 provided on the levers 30 are in contact with each other, and the arc shield divided bodies 4 held by the arc shield holders 44 are also in contact with each other to form the cylindrical arc shield 2. Arc shield 2
The stud 10 is in a state of being inserted therein in the manner shown in FIG. Then, 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 the predetermined position of the base metal 8, and the switch 54 provided on the grip 56 of the welding gun is pressed to perform welding. Do. After the welding is completed, the handle 38 is rotated upward to open the lever 30, and thereafter the 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 the horizontal state, the lever 30 is in the closed state.
When 38 is rotated upward, a joint pin for connecting the other ends of the both links 36 to each other so as to be rotatable as shown in FIG.
34 descends along the long hole 40, both links 36 are tilted as shown in the figure, and both levers 30 are pivoted about the fulcrum pin 28 in the downward opening direction to be opened. Further, when the handle 38 is turned downward from the state shown in FIG. 9, both levers 30 move to the 7th position.
Return to the closed state shown in the figure. In addition, FIG. 8 shows VIII- of FIG.
FIG. 8 is a sectional view taken along line VIII.

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

The welding machine 22 is constructed so that the lever 30 (arc shield divided body 4) is opened and closed within the upper and lower planes including the stud 10, and therefore the lever 30 is opened and closed at right angles to the stud 10, for example. Compared to the structure that is performed in a plane (in a plane parallel to the upper surface of the base material 8), when welding a large number of studs 10, problems such as interference with other studs 10 do not occur.

Further, the handle 38 functions not only for opening and closing the lever 30, but also 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 rearward from the rear surface of the welding gun 48 in the front-back direction (direction of arrow C in FIG. 6), and the handle 38 is 90 ° with respect to the handle 56. It is arranged at an angle of and below. By providing the handle 38 in the direction perpendicular to and below the handle 56 of the welding machine, the grip 56 of the welding machine is grasped by the right hand during welding, and the index finger is placed on the switch 54, and the handle 38 is grasped by the left hand. The welding machine 22 can be held in a well-balanced manner, the welding operator can easily take a stable welding posture, and work efficiency is improved and welding defects are reduced.

Also, the chuck 50 has the stud 10 coaxial with the welding gun 48.
Is configured to be positioned and retained on 52 and chuck 50
The stud 10 gripped by the arc shield holder 44
The lever should be located on the same plane as the two levers 30 to which the levers are attached, that is, the central axis of the stud 10 and the central axis of the two levers 30 should be located on the same plane (a plane extending in the left-right direction and the vertical direction) 30 and a welding gun 48 are provided. Then, with such a configuration, the arc shield 2
Are reliably and evenly brought into contact with the base material, which enables stable welding and improves the reliability of welding.

Further, in the above welding machine 22, the arc shield 2 and the arc shield holding portion 44 are divided into two parts, which are attached to the lower end of the lever 30, and when the stud 10 is attached to the chuck 50, the lever 30 is widely opened to the vicinity of the chuck 50. Since a large space is secured in the stud 10, the stud 10 can be easily attached 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, whereby both arcs when the lever 30 is closed. Proper abutment of the shield holding portion 44 and thus the arc shield division body 4 is ensured.

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

10 is a sectional view taken along the line XX of FIG. 11, and FIG. 11 is a sectional view of FIG.
FIG. 6 is a cross-sectional view taken along line XI-XI, showing a state in which the lever 30 is closed and a pair of arc shield split bodies 4 are brought into contact with each other, whereby a cylindrical arc shield 2 is formed. .

As shown in the figure, each holding part main body 62 is formed with a semi-cylindrical inner holding part 60 in contact with the inner side surface of the semi-cylindrical held part 20 of the arc shield divided body, and the arc shield divided body 4 is covered with the covered part. The inner surface of the holding portion 20 is brought into contact with the outer surface of the inner holding portion 60 so as to be attached to the holding portion main body 62, and each held portion 20
Two 1 / 4-cylindrical (circular arcs with a cross section of 90 °) outer gripping portions 64 are disposed on the outside of each of the outer gripping portions 64, and each outer gripping portion 64 is a pressing member screwed to the holding portion main body 62. Pressure screw
It is pressed in the direction of the center (the center of the cylindrical arc shield 2 when the cylindrical arc shield 2 is formed by abutting the arc shield divided body 4), whereby the arc shield divided body 4 is moved to the inside and outside. It is held by the holding units 60 and 64.

The pressing of the outer holding portion 64 by the pressing screw 70 causes the tip of the pressing screw 70 to be pressed toward the center at the central portion of the outer holding portion 64 (the central portion in the 90 ° arc direction). Abutting against the central portion of 64 and pressing screw 70
The axis of is oriented toward the center.

When the cylindrical arc shield 2 is divided into two and each arc shield divided body 4 is held, as described above, the semi-cylindrical inner holding part 60 and the two 1/4 cylindrical outer holding parts 64 are sandwiched. ,
Moreover, by adopting a configuration in which each outer holding portion 64 is pressed in the central direction in the central portion, the difference in the coefficient of thermal expansion between the arc shield split body 4 and the holding portion main body 62 and the outer holding portion 64 at the time of welding. The arc shield division body 4 is prevented from cracking or the like.

That is, the inner and outer holding parts 60, 64 and the held part 20 of the arc shield divided body are in contact with each other over the entire area before welding, as shown in FIG. 12 which is a plan view. When welding is performed from this state and the temperature becomes high, the respective parts 60, 20, 64 thermally expand. In this case, the arc shield divided body 4 is made of ceramics as described above, and the inner and outer holding portions 60, 64 are made of a metal having a good thermal conductivity such as copper to improve heat dissipation, and the ceramics are almost Although it does not expand very much, metal greatly expands. Therefore, if the outer holding portion 64 is also a semi-cylindrical shape and the outer holding portion 64 is pressed in the central direction in the circumferential center portion thereof, as shown in FIG. 13, the held portion of the arc shield divided body is held. 20 is in contact with the outer holding portion 64 ′ only at its central portion and receives a force in the central direction from the central portion, and is in contact with the inner holding portion 60 only at both end portions and receives a reaction force directed outward from the both end portions. As can be easily understood from FIG. 13, an extremely large thermal stress (bending moment) acts on the arc shield divided body 4 to cause cracks and breakage easily.

On the other hand, in the above welding machine, the semi-cylindrical outer holding portion 64 ′ is further divided into two 1/4 cylindrical outer holding portions 64, and each of the 1/4 cylindrical outer holding portions 64 is Since it is configured to apply a pressing force in the central direction in the circumferential central portion, the action state of force during thermal expansion is as shown in Fig. 14, and as is easily understood from this diagram, the arc The thermal stress (bending moment) acting on the shield divided body 4 is much smaller than that in the case shown in FIG. 13, so that the arc shield divided body 4 is likely to be damaged or broken due to the difference in thermal expansion coefficient. It is being reduced.

A locking screw 72 is screwed into the pressing screw 70, and the outer holding portion 64 is fitted and locked in the locking screw 72. This prevents the outer holding portion 64 from falling off the holding portion main body 62 when the pressing of the outer holding portion 64 by the pressing screw 70 is released.

Further, the locking screw 72 is loosely fitted and inserted into the outer holding portion 64 with a predetermined gap, and this and the tip portion of the pressing screw 70 (the portion that presses the outer holding portion 64) have a substantially conical shape. By so doing, the degree of freedom of displacement of the outer holding portion 64 with respect to the pressing screw 70 is increased, and thereby the force acting on the arc shield divided body 4 at the time of the thermal expansion is reduced.

Similarly, in order to reduce the force acting on the arc shield split body 4 during thermal expansion, although not shown, for example, the tip pressing portion of the pressing screw 70 is displaced toward the center by a buffer mechanism such as a spring. You may support it as much as possible.

Further, as described above, the arc shield holding portion 44 (holding portion main body 62 and outer sandwiching portion 64) is made of copper or its alloy having high thermal conductivity, and the holding portion main body is provided on the outer periphery of the arc shield holding portion 44. Radiation fin integrated with 62
74, the high heat generated during welding is efficiently dissipated into the air without being stored in the ceramic arc shield, high temperature deterioration of the arc shield is prevented, and the life is extended. There is.

Further, the arc shield holding portion 44 has a predetermined length and small diameter between the step portion of the lever 30 (step portion between the small diameter portion 30a and the large diameter portion 30b) and the nut 68 via the holding portion main body 62. The lever large-diameter portion 30b is slidably provided along the portion 30a, 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 portion main body 62. A buffer mechanism for the arc shield 2 is constituted by them, and this buffer mechanism enables the ceramic arc shield 2 to be stably pressed against the base material 8 during welding without applying an 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 chain double-dashed line in FIG. 5, but the welding machine 22 is directed toward the base metal 8 during welding. When pressing, the lower end of the lever 30 contacts the upper surface of the base material 8. In other words, all the pressing force of the worker 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 constantly forced by the compression spring 78 to a certain degree. The structure is such that it is pressed against the base material 8 with no pressing force.

Further, the arc shield 2 is entirely covered with the arc shield holding portion 44, thereby preventing the arc shield 2 from directly hitting and damaging an external object.

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

The arc shield 2 may be made of any material as long as it is made of a material having excellent thermal shock resistance and low adhesion to molten metal. For example, one made of ceramics containing 20% by weight or more of boron nitride is preferable. 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 (1,300 ° C. or higher) during arc welding and has no adhesion to the weld metal. It 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 having a semi-cylindrical inner holding part and two 1/4 cylindrical outer sides. Clap with the holding unit,
Since the pressing means presses each 1/4 cylindrical outer holding portion toward the arc shield divided body at a substantially central position in the circumferential direction, the arc shield divided body is configured to be held. Further, the thermal stress due to the difference in the coefficient of thermal expansion can be sufficiently reduced, and the arc shield divided body can be held well. .

[Brief description of the drawings]

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 a usage state of the arc shield shown in FIG. Fig. 5 is a front view showing an embodiment of an arc stud welder according to the present invention, Fig. 6 is a right side view of the welder shown in Fig. 5, and Figs. 7 and 9 are Fig. 5 8 is a front view showing the lever opening / closing mechanism of the welding machine shown in FIG. 8, FIG. 8 is a sectional view taken along line VIII-VIII of FIG. 7, and FIGS. 10 and 11 are details of the arc shield holding portion of the welding machine shown in FIG. FIG. 10 is a sectional view taken along line XX in FIG. 11, FIG. 11 is a sectional view taken along line XI-XI in FIG. 10, and FIGS. 12, 13, and 14 are arcs at high temperature. It is a top view for explaining change of a shield holding state. 2 …… Arc shield 4 …… Arc shield divided body 22 …… Arc stud welder 44 …… Arc shield holding part 60 …… Inner gripping part 64 …… Outer gripping part 70 …… Pressing means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-23072 (JP, A) JP-A-59-141379 (JP, A) JP-A-60-181269 (JP, U)

Claims (1)

(57) [Claims] 1. An arc stud welding machine comprising an arc shield holding portion for holding a substantially semi-cylindrical arc shield divided body, wherein the arc shield holding portion contacts an inner surface of the arc shield divided body. The semi-cylindrical inner gripping portion, the two 1/4 cylindrical outer gripping portions that come into contact with the outer surface of the arc shield split body, and the outer gripping portions at the substantially central position in the circumferential direction. An arc stud welding machine, comprising: a pressing means for pressing the arc shield divided body.