JP2007054872A - Welding torch for gas shielded arc welding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a welding torch for gas shielded arc welding capable of suppressing the projecting flow rate of a shielding gas produced upon the operation of a welding machine. <P>SOLUTION: A hollow region 11 where a torch body 10 and a welding tip 18 are joined and communicates with each other is provided with a small-diameter path 20 whose diameter is fine and which has a shielding gas exhaust nozzle 22, thus, when a shielding gas passes through the small-diameter path 20 having a fine diameter, its flow can be restricted. Thus, the projecting flow rate of the shielding gas can be reduced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a welding torch for arc welding, and more particularly to a welding torch for gas-encapsulated arc welding used for gas-encapsulated arc welding.

  One means for joining metals is gas-encapsulated arc welding that uses argon, helium, carbon dioxide, or the like as a shielding gas. There are two types of gas-encapsulated arc welding: consumable electrode type welding using a consumable electrode (welding wire) and non-consumable electrode type melting using a non-consumable electrode.

  FIG. 5 shows a longitudinal sectional view of the former welding torch for consumable electrode welding. The welding tip 100 which is the tip of the welding torch is fixedly coupled to the tip of the torch body 104, and the welding nozzle 102 opens a nozzle space 103 which is a predetermined gap between the welding tip 100 and the torch body 104, It is attached. Further, the welding tip 100 and the torch main body 104 have a hollow region 105 formed in communication with the inside. The hollow region 105 is configured as a shield gas through hole 106 having a large inner diameter inside the torch body 104 and as a welding wire passage 107 through which the welding wire 112 passes inside the welding tip 100. Further, six shield gas ejection holes 108 are provided at equal intervals on the side wall portion of the shield gas passage hole 106.

  The operation state of this conventional welding torch will be described. A welding wire 112 serving as a consumable electrode and a filler material is automatically fed to a shield gas through hole 106 of the torch body 104 by a feeding means (not shown), and a voltage is supplied to the welding wire 112 from a welding power source (not shown). Applied. Thus, an arc is generated between the welding wire 112 and the member to be welded W, and the member to be welded and the welding wire 112 itself are melted and joined.

  Further, the shield gas X is supplied from a supply means (not shown) to the shield gas passage hole 106, is injected from the shield gas ejection hole 108 into the nozzle interior 103 of the welding nozzle 102, passes through the nozzle, and passes through the nozzle opening 103. The weld is sprayed in a ring shape. This shield gas X is used to shield molten metal from the atmosphere so as not to generate blow holes (bubbles) in the welded member W and to protect and stabilize the arc.

  In such consumable electrode type welding, spatter may adhere to the tip of the welding tip 100 or the welding nozzle 102. If the spatter is left unattached, the welding tip 100 comes into contact with the welding nozzle 102, or the lower end of the welding nozzle 102 touches the member to be welded. When this state occurs, it may become an electric contact (short circuit) state, or the flow of the shield gas X may be disturbed to cause blow holes during welding.

  Means for dealing with the situation of spatter adhesion in the above consumable electrode type welding is described in many patent documents. For example, the wall surface of the welding nozzle and the surface of the welding tip body are covered with an insulating resin, for example, a fluororesin tube or a urethane sheet (Patent Document 1). According to this, even if spatter adheres to the welding nozzle and the welding tip, they are covered with an insulating resin, so that it is difficult for a short state to occur.

  Further, there is an invention relating to a nozzle for a gas encapsulated arc welding torch, in which a coating film having heat resistance, for example, an epoxy resin is applied to the entire surface of the welding nozzle (Patent Document 2). According to this, spatter generated during welding work flies toward the coating film such as epoxy resin coated on the welding nozzle, but since the affinity between the spatter and the coating film is low, the spatter is a welding nozzle. It becomes difficult to adhere to.

Japanese Utility Model Publication No. 5-5257 JP 2003-220472 A

  However, the techniques shown in Patent Document 1 and Patent Document 2 include the following problems with respect to the amount of shield gas ejected. That is, during a short time after switching from the stopped state to the activated state (a time immediately after the start of the supply of the shield gas), about twice the set flow rate is released from the shield gas ejection hole (at this time). The shield gas flow rate is called "protruding flow rate"). Such a protruding flow rate at the start of use means that the amount of shield gas used is unnecessarily increased (see the two-dot chain line in FIG. 4). The protruding flow rate of this shielding gas is not so much a problem when the welding machine has been in operation for a long time, but if it is necessary to frequently switch between the stopped state and the operating state for the convenience of welding work, the shielding gas will Since it flows twice as much as the set flow rate, it is a great waste.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a welding torch for gas-encapsulated arc welding that can suppress the protruding flow rate of shield gas generated during operation of a welding machine. It is to be.

  The invention of a welding torch for gas-encapsulated arc welding according to claim 1, which achieves the above object, comprises a welding tip provided at a tip portion, a torch body connected to the welding tip, the welding tip and the torch. A welding nozzle that covers the body with a predetermined gap, and a hollow region for allowing a shield gas and a welding wire to pass therethrough is formed in communication between the welding tip and the torch body, and a side wall of the hollow region In the welding torch provided with a shield gas injection hole for injecting a shield gas in the part, the hollow region has a small-diameter passage with a small inner diameter reduced over a predetermined length from the upstream side to the downstream side of the shield gas. And the shield gas ejection hole is formed in a side wall portion of the small diameter passage.

  According to a second aspect of the present invention, in the welding torch for gas-encapsulated arc welding according to the first aspect, the small-diameter passage forms a first tapered portion in the hollow region inside the torch body to reduce the diameter. The small diameter state is continuously formed up to a predetermined position of the tip, a second taper portion is formed at the end of the small diameter passage inside the welding tip to further reduce the diameter, and the welding wire extends to the tip of the welding tip. It is characterized by the fact that it is a passage for use.

  According to a third aspect of the present invention, in the welding torch for gas-encapsulated arc welding according to the second aspect, the shield gas ejection hole is provided in the vicinity of the second tapered portion of the small diameter passage in the welding tip. It is characterized by.

  A fourth aspect of the present invention is the welding torch for gas-encapsulated arc welding according to any one of the first to third aspects, wherein the welding nozzle is a short nozzle in which the tip protrusion amount of the welding tip is increased. It is characterized by that.

  According to the first aspect of the present invention, the shield gas is supplied to the hollow region, flows into the small-diameter passage having a narrowed inner diameter over a predetermined length, and is ejected from the shield gas ejection hole provided there. In this process, the shield gas must pass through a small-diameter passage with a narrowed inner diameter, and the gas flow is restricted in the portion of the small-diameter passage. Accordingly, the flow rate from the shield gas ejection hole when the shield gas is introduced is limited, and the protruding flow rate of the shield gas can be suppressed. In addition, after the elapse of the time zone in which the protruding flow rate occurs, the flow rate does not drop and there is no problem.

  In the invention of claim 2, the hollow region between the first taper portion and the second taper portion formed from the torch body to the welding tip becomes a small-diameter passage. You can definitely get it.

  In the invention of claim 3, by providing the shield gas ejection hole in the vicinity of the second taper portion of the small diameter passage of the welding tip, the distance between the shield gas ejection hole and the welded portion to be welded is shortened. As a result, the jet velocity of the shield gas from the shield gas jet hole can be maintained at a high speed and jetted to the welded portion, the flow of the shield gas jet is less likely to be disturbed, and the welded portion is protected well by the shield gas. Can be.

  According to the fourth aspect of the present invention, since the distance from the welded portion to the tip of the welding nozzle is increased, it is possible to significantly reduce the spatter adhesion to the welding nozzle that occurs during the welding operation. This is because the flow rate of the shield gas increases as the shield gas passes through the small-diameter passage having a narrowed inner diameter, and the shield gas from the shield gas blowout hole is accordingly increased. Gas injection speed increases. Therefore, even if the welding nozzle is shortened as in the invention according to this claim, the shield gas is sprayed on the welded portion without diffusing greatly, so that there is no problem in the function of stabilizing the arc. Therefore, it is possible to reduce spatter adhesion while limiting the protruding flow rate.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a welding torch for arc welding according to the present invention will be described in detail with reference to the drawings. FIG. 1 shows a longitudinal sectional view of a welding torch 1 of a consumable electrode type gas-encapsulated arc welding machine according to an embodiment of the present invention. In the welding torch 1, the welding tip 18, which is the tip, is coupled and fixed by screwing at the torch body 10 and the joint 16. Further, a welding nozzle 28 is coupled and fixed to the torch body 10 at a joint 30, and the welding nozzle 28 opens a nozzle space 28 a which is a predetermined gap except for the welding tip 18 and the tip of the torch body 10. Covering. The length of the cover portion of the welding nozzle 28 is set to be shorter than that of the conventional configuration of FIG. 5, that is, the tip end portion 18 a of the welding tip 18 has the same protruding amount from the nozzle tip opening 28 b of the welding nozzle 28. It is about 1 mm longer than the configuration.

  Further, in the coupled state of the torch body 10 and the welding tip 18, the hollow region 11 is formed in communication within the torch body 10 and the welding tip 18. The hollow region 11 is configured as a large-diameter shield gas passage hole 12 inside the torch body 10 and is reduced in diameter by a first taper portion 14 formed in the vicinity of the joint portion 16 inside the torch body 10. It is stretched. From the first taper portion 14, a reduced-diameter passage 20 is formed, and extends to a second taper portion 19 provided in the vicinity of the substantially central portion of the welding tip 18. Further, the diameter is reduced by the second taper portion 19 to form a welding wire passage 26 penetrating to the tip end portion 18 a of the welding tip 18.

  In the present embodiment, the inner diameter of the shield gas passage hole 12 from the upper end to the vicinity of the lower end of the torch body 10 is about 6 mm, and the small diameter from the vicinity of the lower end of the torch body 10 to the middle position of the welding tip 18. The passage has an inner diameter of about 2.5 mm, and the continuous welding wire-like passage has an inner diameter of about 1.2 mm.

  FIG. 2 is a longitudinal sectional view showing only the welding tip 18 extracted. As shown in the drawing, a shield gas ejection hole having a diameter of about 1 mm is provided at a position below the tip uppermost end 18b which is the uppermost portion of the welding tip 18 in the drawing. 22 are provided at four equal intervals. Note that the number is less than six of the shield gas ejection holes 108 provided in the conventional welding torch shown in FIG. The distance L1 from the tip uppermost end 18b to the shield gas ejection hole 22 is set to 15 mm, and the distance L2 from the tip uppermost end 18b to the second tapered portion 19 is set to 20 mm.

  Next, the operation and effect of the welding torch 1 having the above configuration will be described. FIG. 3 is an explanatory view showing an operating state of the welding torch of FIG. When an input power supply (not shown) is turned on, a gas valve (not shown) provided in a gas passage from an inert gas (for example, argon) supply source is opened, and a shield gas X which is an inert gas is a torch main body. At the same time, the welding wire 24 is sent to the shield gas through hole 12 from a wire feeder (not shown). The shield gas X passes through the shield gas passage hole 12, the first tapered portion 14, and the small diameter passage 20, and is ejected from the shield gas ejection hole 22, passes through the nozzle space 28a, and travels from the nozzle tip port 28b toward the welded portion. Is injected. Further, the welding wire 24 passes through the shield gas through hole 12, the small diameter passage 20, and the welding wire passage 26 and is fed in the direction of the member W to be welded.

  With the above-described configuration, even if the shield gas X is sent from the shield gas passage hole 12, the shield gas has a small diameter passage 20 because it receives physical resistance when passing through the first tapered portion 14 having a narrow region. Inflow is restricted. Therefore, if the shield gas source pressure is constant, the above-mentioned “projection flow rate” can be reduced. A graph showing the decrease in the protruding flow rate is shown in FIG.

  FIG. 4 shows the flow rate of the shield gas X ejected from the nozzle tip port 28b per time. A solid line 60 represents the set flow rate, a two-dot chain line 62 represents the conventional “projection flow rate”, and a one-dot chain line 64 represents the “projection flow rate” in the present embodiment. As can be understood from the figure, the “protruding flow rate” in the present embodiment indicated by the one-dot chain line 64 is higher than the set flow rate, but is lower than the conventional “protruding flow rate” indicated by the two-dot chain line 62. Yes. Specifically, the “protruding flow rate” in the present embodiment indicated by the one-dot chain line 64 is about 20% lower than the conventional “protruding flow rate” indicated by the two-dot chain line 62. Thereby, the waste of cost due to the “projection flow rate” can be significantly suppressed.

  Further, the shield gas X passes through the first tapered portion 14 from the shield gas through hole 12 and flows into the small diameter passage 20 having a relatively narrow diameter, so that the shield gas X is narrowed and the flow velocity is increased. Furthermore, since the shield gas ejection hole 22 is closer to the welded portion than in the prior art, a decrease in the flow rate of the shield gas is suppressed until the shield gas ejection hole 22 is sprayed onto the welded portion. Therefore, the shield gas X released from the shield gas ejection hole 22 has a high flow rate even when released from the nozzle tip port 28b, and is sprayed without diffusing from the nozzle tip port 28b toward the welded portion.

  In this embodiment, since the welding nozzle 28 is short, the tip end portion 18a protrudes from the nozzle tip port 28b as compared with the conventional one, and as a result, the distance from the tip of the welding nozzle 28 to the welded portion is increased. However, as described above, the shielding gas X is ejected from the nozzle tip port 28b with a flow velocity increased as compared with the conventional case. Therefore, even if the welding nozzle 28 is shortened, the gas flow is not diffused to the welded portion. Be sprayed. By the above, the function which interrupts | blocks and protects an arc from external air can be maintained similarly to the past.

  Furthermore, since the tip of the welding nozzle 28 has a structure separated from the welded portion, spatter scattered from the welded portion is difficult to adhere to the tip of the welding nozzle 28. Even if spatter adheres, since the welding nozzle 28 is short and the distance from the member W to be welded is small, the welding nozzle 28 and the member W to be welded are difficult to contact. A short state caused by contact with the welding member W can be prevented. Therefore, the cleaning cycle of the welding nozzle 28 can be extended, and the working efficiency is increased.

  Specifically, when the welding current is 180 A, the welding voltage is 22 V, the inner diameter of the welding wire is 1.2 mm, and the distance from the tip of the welding tip 18 to the member to be welded is 15 mm, the cleaning period is about 66% at maximum. Can be extended. As described above, the welding torch 1 according to the present embodiment not only reduces the “projection flow rate” of the target shielding gas, but also reduces spatter adhesion to the welding nozzle 28 at the same time, This has the effect of extending the cleaning cycle.

  Moreover, although the said embodiment showed the application example to a consumable electrode type gas-encapsulated arc welding machine, the present invention is applied to a non-consumable electrode type gas-encapsulated arc welder in which the welding wire 24 is changed to a non-consumable electrode. Can be applied. In this case, the same configuration as the above-described consumable electrode type gas-encapsulated arc welding welding torch can be applied, and the protruding flow rate of the shielding gas can be suppressed.

  In addition, this invention is not limited to the said embodiment, A various change is possible within the range of the summary of invention. For example, the inner diameter of the shield gas passage hole 12 and the small diameter passage 20, and the number and size of the shield gas ejection holes can be adjusted within the range where the function of the present invention is exhibited.

It is a longitudinal cross-sectional view of the welding torch of the gas envelope arc welding machine in this Embodiment. It is a longitudinal cross-sectional view of only the welding tip of FIG. It is explanatory drawing which shows the operation state of the welding torch of FIG. It is the figure which made the graph the comparison of the protrusion flow volume in this Embodiment, a setting flow volume, and the conventional protrusion flow volume by making a horizontal axis into time and a vertical axis | shaft. It is a longitudinal cross-sectional view of the welding torch of the conventional gas envelope arc welding machine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Welding torch 10 Torch main body 11 Hollow area | region 12 Shield gas through-hole 14 1st taper part 18 Welding tip 18a Tip front-end | tip part 19 2nd taper part 20 Small diameter passage 22 Shield gas ejection hole 26 Welding wire passage 28 Welding nozzle 28a Nozzle space 28b Nozzle tip port 62 Projection flow rate of shield gas in conventional arc welding machine 64 Projection flow rate of shield gas in arc welding machine of the present invention

Claims (4)

A welding tip provided at the tip, a torch body coupled to the welding tip,
A welding nozzle that covers the welding tip and the torch body with a predetermined gap; and
A hollow region for allowing a shield gas and a welding wire to pass therethrough is formed in communication with the welding tip and the torch body,
In the welding torch provided with shield gas ejection holes for ejecting shield gas in the side wall portion of the hollow region,
The hollow region is
Having a small-diameter passage whose inner diameter is reduced over a predetermined length on the downstream side from the upstream side of the shielding gas;
The shield gas ejection hole is
A welding torch for gas-encapsulated arc welding formed on a side wall portion of the small-diameter passage. The small diameter passage is
The first tapered portion is formed in the hollow region inside the torch body to reduce the diameter, and this small diameter state is continuously formed up to a predetermined position of the chip,
2. The gas container according to claim 1, wherein a second taper portion is formed at the end of the small diameter passage inside the welding tip to further reduce the diameter, and a welding wire passage is formed up to the tip of the welding tip. Welding torch for envelope arc welding. The shield gas ejection hole is
The welding torch for gas-encapsulated arc welding according to claim 2, wherein the welding torch is provided in the vicinity of a second tapered portion of the small diameter passage in the welding tip. The welding nozzle is
The welding torch for gas-encapsulated arc welding according to any one of claims 1 to 3, wherein the nozzle is a short nozzle with an increased amount of protrusion of the tip of the welding tip.

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