JP2006326677A - Welding equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide welding equipment where the projecting flow rate of a shielding gas is suppressed by a simple constitution. <P>SOLUTION: The middle position of a shielding gas flow passage 31 for allowing a shielding gas feed source 5 to communicate with a welding torch 20 is provided with a shielding gas flow rate controlling means, thus, when a gas valve 30 is opened, the temporary increase in the flow rate of a shielding gas flowing through the shielding gas flow passage 31 larger than the previously set flow rate is suppressed, and the useless consumption of the shielding gas is suppressed, so as to reduce the consumption of the shielding gas. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a welding apparatus, and more particularly to a gas shield type welding apparatus that ejects a shielding gas from a welding torch.

  Conventionally, in order to prevent so-called blowholes from being generated in the welded portion of the metal base material, an inert gas such as carbon dioxide gas or argon is blown from the welding torch as a shielding gas and sprayed onto the metal melted part. There is a shield gas type welding apparatus that performs welding while isolating the molten metal portion from the surrounding air atmosphere.

  This shield gas type welding apparatus has a gas valve in the middle of the shield gas flow path that communicates between the shield gas supply source and the welding torch, and opens the gas valve at the start of welding to enter the shield gas flow path. The shield gas is circulated and ejected from the welding torch, and the gas valve is closed at the end of welding to stop the ejection of the shield gas.

  The shield gas supplied from the shield gas supply source is set by a regulator and a flow meter so as to have a preset set flow rate, but when the gas valve is opened, the flow rate of the shield gas flowing in the shield gas flow path The shield gas temporarily flows toward the downstream side due to the pressure difference between the upstream side and the downstream side of the gas valve, so that the flow rate is temporarily about twice the set flow rate. Then, immediately after that, the pressure difference between the upstream side and the downstream side of the gas valve is eliminated and the set flow rate is obtained. Therefore, conventionally, when the gas valve is opened, a phenomenon has occurred in which the flow rate of the shield gas passing through the shield gas passage temporarily increases from the set flow rate.

  In addition, various factors affecting the shielding effect during welding, such as the distance between the tip of the nozzle for the shielding gas and the surface of the base metal, the surrounding wind speed, welding current, welding speed, etc., have been detected. There has been proposed a consumable electrode type arc welding machine equipped with a gas flow rate adjuster that adjusts the flow rate of the shield gas in accordance with (see, for example, Patent Document 1).

JP-A-5-261547

  However, a flow rate exceeding the set flow rate that is generated when the gas valve is opened (hereinafter referred to as a protruding flow rate) is unnecessary and is a wasteful consumption of shield gas. In particular, when the welding length is short and the welding time is short, the ratio of the protruding flow rate to the total flow rate of the shielding gas increases, which increases the consumption of expensive shielding gas and increases the cost. And wasted resources.

  Moreover, in the case of the consumable electrode type arc welding apparatus provided with the gas flow rate regulator described in Patent Document 1, a plurality of sensors for detecting various factors are provided, and shielding is performed based on information detected by the plurality of sensors. It is necessary to adjust the flow rate of the gas, and there is a problem that the structure and control become complicated.

  In view of these problems, the present invention has been made to solve the problems of the prior art, and an object of the present invention is to provide a welding apparatus that can reduce the consumption of shield gas by suppressing the waste of shield gas with a simple configuration. It is to provide.

  According to a first aspect of the present invention, there is provided a welding apparatus that shields a welding gas from a welding torch by an opening / closing operation of a gas valve provided in the middle of a shielding gas flow path that communicates between a shielding gas supply source and the welding torch. In a welding device that ejects gas, by opening the gas valve, the flow rate of the shield gas flowing from the upstream side to the downstream side in the shield gas flow path is prevented from temporarily increasing from a preset flow rate. The shield gas flow rate control means is provided in the middle of the shield gas flow path.

  According to a second aspect of the present invention, in the welding apparatus according to the first aspect, the shield gas flow rate control means has a flow passage area smaller than the flow passage area of the shield gas flow passage and is upstream of the gas valve. It is characterized by comprising an orifice provided in at least one of the midway position of the shield gas flow path and the midway position of the shield gas flow path downstream of the gas valve.

  According to a third aspect of the present invention, in the welding apparatus according to the first aspect, the shield gas flow rate control means has a flow passage area smaller than the flow passage area of the shield gas flow passage and is upstream of the gas valve. It is characterized by comprising a tube provided at at least one of the midway position of the shield gas flow path and the midway position of the shield gas flow path downstream of the gas valve.

  According to a fourth aspect of the present invention, in the welding apparatus according to the first aspect, the shield gas flow rate control means has a predetermined volume space and is provided at an intermediate position of the shield gas flow path downstream of the gas valve. It is characterized by comprising a chamber.

  According to a fifth aspect of the present invention, in the welding apparatus according to the first aspect, the shield gas flow rate control means includes an upstream end connected to the shield gas flow path upstream of the gas valve and a downstream side of the gas valve. A bypass flow path having a downstream end connected to the shield gas flow path to bypass the gas valve, and a bypass flow path having a flow area smaller than the flow area of the shield gas flow path provided in the flow path of the bypass passage It is characterized by comprising a bypass valve that opens and closes the inside and valve control means that opens the bypass valve and opens the gas valve after a preset time has elapsed from the opening operation.

  According to the first aspect of the present invention, since the flow rate of the shield gas passing through the shield gas passage is prevented from temporarily increasing above the set flow rate at the start of the injection of the shield gas, the gas valve is opened. The generated protruding flow rate can be reduced, wasteful consumption of shield gas can be suppressed, and the consumption amount of shield gas can be reduced.

  The invention according to claim 2 shows an example of a specific configuration of the shield gas flow rate control means. According to this, the shield gas flow rate control means is more than the flow path area of the shield gas flow path. Since it is composed of an orifice provided in at least one of the midway position of the shield gas flow path upstream of the gas valve and the midway position of the shield gas flow path downstream of the gas valve having a small flow path area, When the shield gas passes through the orifice, its flow rate can be reduced. Therefore, when the gas valve is opened, it is possible to prevent the shield gas from flowing into the downstream side of the shield gas flow path. Thereby, it can suppress that the flow volume of the shield gas which passes the inside of a shield gas flow path increases temporarily rather than a setting flow volume, and can reduce a protrusion flow volume.

  The invention according to claim 3 shows an example of a specific configuration of the shield gas flow rate control means. According to this, the shield gas flow rate control means is more than the flow path area of the shield gas flow path. Since it has a small flow path area and is configured by a tube provided at least one of the middle position of the shield gas flow path upstream of the gas valve and the middle position of the shield gas flow path downstream of the gas valve, The flow rate of the shielding gas can be reduced when it passes through the tube. Therefore, when the gas valve is opened, it is possible to prevent the shield gas from flowing into the downstream side of the shield gas flow path. Thereby, when the gas valve is opened, it is possible to suppress the flow rate of the shield gas passing through the shield gas flow path from temporarily increasing from the set flow rate, and to reduce the protruding flow rate. In addition, for example, a general-purpose tube that is generally distributed can be used as it is, and the implementation is extremely easy and can be performed at low cost.

  The invention according to claim 4 shows an example of a specific configuration of the shield gas flow rate control means. According to this, the shield gas flow rate control means has a predetermined volume space and is provided with a gas valve. Since the chamber is provided in the middle of the shield gas flow path on the downstream side, when the gas valve is opened, the pressure of the shield gas flowing into the chamber from the upstream side of the shield gas flow path is reduced. Can be sent downstream.

  Accordingly, the pressure difference between the upstream side and the downstream side of the shield gas flow path can be absorbed by the chamber, and the shield gas can be prevented from flowing into the downstream side of the shield gas flow path. Thereby, it can suppress that the flow volume of the shield gas which passes the inside of a shield gas flow path increases temporarily rather than a setting flow volume, and can reduce a protrusion flow volume.

  The invention according to claim 5 shows an example of a specific configuration of the shield gas flow rate control means, and the shield gas flow rate control means has an upstream end connected to the shield gas flow path upstream of the gas valve. In addition, the downstream end is connected to the shield gas flow path downstream of the gas valve to bypass the gas valve, and the flow path area of the shield gas flow path is smaller than the shield gas flow path provided in the flow path of the bypass passage. The bypass valve has a flow passage area and opens and closes the inside of the bypass flow passage, and valve control means for opening the bypass valve and opening the gas valve after a preset time has elapsed since the opening operation. ing.

  According to this, since the bypass valve is first opened and the shield gas is allowed to pass through the bypass valve having a channel area smaller than the channel area of the shield gas channel, the flow rate of the shield gas can be reduced. It is possible to prevent the shield gas from flowing into the downstream side of the shield gas passage when the bypass valve is opened.

  And, for example, the time from when the bypass valve is opened until the pressure on the downstream side of the shield gas passage rises to some extent, the time until the protruding flow rate of shield gas by the bypass valve opens, etc. By opening the gas valve after a preset time has elapsed since the opening operation, the pressure difference between the upstream side and the downstream side of the shield gas flow path can be reduced. Therefore, when the gas valve is opened, the shield gas can be prevented from flowing all at once, and the flow rate of the shield gas passing through the shield gas channel is prevented from temporarily increasing from the set flow rate. The protrusion flow rate can be reduced.

Next, first to fourth embodiments of the present invention will be described below.
(First embodiment)
FIG. 1 is an overall view of a consumable electrode arc welding apparatus 1 according to the first embodiment. As shown in FIG. 1, the consumable electrode type arc welding apparatus 1 includes a robot arm 10 having multiple axes and robot control means 14 for controlling the robot arm 10. Is fitted with a known welding torch 20.

  The welding torch 20 is connected to the shield gas supply source 5 through a shield gas flow path 31 formed by gas hoses 32 and 33 having the same inner diameter, and is connected from the shield gas supply source 5 to the shield gas flow path 31. The shield gas supplied through the nozzle 21 can be ejected from the tip of the nozzle 21. The flow rate of the shield gas supplied from the shield gas supply source 5 is adjusted to be a preset flow rate set in advance by a regulator 6 and a flow meter 7 provided in the shield gas supply source 5.

  Further, the welding torch 20 is connected to a welding power source and generates an arc discharge between the welding wire 2 fed out from the electrode tip 22 provided at the tip of the nozzle 21 and a workpiece (not shown) to perform welding. Is configured to do.

  A known gas valve 30 and wire feeding means 40 are attached to the intermediate portion 12 of the robot arm 10 via the base plate 13. The gas valve 30 is provided in the middle of the shield gas flow path 31 that communicates between the welding torch 20 and the shield gas supply source 5, and the shield gas flow path 31 is provided between the gas valve 30 and the shield gas supply source 5. The gas valve 30 and the welding torch 20 are connected by a gas hose 33 in the shield gas flow path 31.

  The gas valve 30 opens and closes in response to a control signal from the valve control means 50 so that the welding torch 20 and the shield gas supply source 5 can be communicated with each other. The valve control unit 50 is configured to open and close the gas valve 30 based on the arc welding start command and the arc welding end command from the robot control unit 14.

  The wire feeding means 40 drives a feeding motor (not shown) according to the opening operation of the gas valve 30 by the valve control means 50, pulls out the welding wire 2 from the wire reel 3, and performs welding at a feeding speed corresponding to the welding speed. It is configured to supply to the torch 20.

  FIG. 2 is an enlarged view of a portion A in FIG. 1, and FIG. 3 is a cross-sectional view for explaining the structure of the tube 61 constituting the shield gas flow rate control means 60 in the first embodiment. As shown in FIG. 2, a tube 61 is provided in the middle of the shield gas flow path 31. As shown in FIG. 3, the tube 61 has a tubular shape having an inner diameter smaller than the inner diameter of the gas hoses 32, 33 and an outer diameter larger than the inner diameter of the gas hoses 32, 33. The shield gas channel 31 has a channel area smaller than the channel area.

  The outer diameter of the tube 61 is set to a size that allows the end portions of the gas hoses 32 and 33 to be fitted and connected. The inner diameter of the tube 61 constitutes an orifice that restricts the flow rate of the shield gas flowing in the shield gas flow path 31, and when the gas valve 30 is opened, the shield gas is caused by the pressure difference between the upstream side and the downstream side of the gas valve 30. The size is set such that it can be prevented from flowing from the upstream side to the downstream side of the shield gas passage 31 at a stretch. And in this Embodiment, as shown in FIG. 2, the tube 61 is each provided in the upstream of the gas valve 30, and the downstream.

  Next, a method of performing welding with the above consumable electrode type arc welding apparatus 1 will be described. First, when the workpiece is positioned and fixed at a predetermined position and the welding torch 20 is moved to the welding start position of the workpiece by the robot arm 10, an arc welding start command is sent from the robot control means 14 to the valve control means 50.

  When receiving the arc welding start command from the robot control means 14, the valve control means 50 opens the gas valve 30. Thereby, the shielding gas is supplied from the shielding gas supply source 5 to the welding torch 20, the shielding gas is ejected from the nozzle 21, and welding to the workpiece is started.

  According to the consumable electrode type arc welding apparatus having the above configuration, the tubes 61 constituting the orifices are provided on the upstream side and the downstream side of the gas valve 30, respectively. Therefore, the flow rate of the shielding gas is first throttled when passing through the upstream tube 61 and expanded after passing, and when the gas passes through the gas valve 30 and passes through the downstream tube 61, the flow rate is reduced again. Expanded again after being passed.

  Therefore, when the gas valve 30 is opened, the shield gas is prevented from flowing into the downstream side of the shield gas passage 31 at a stretch, and the flow rate of the shield gas passing through the shield gas passage 31 is temporarily increased from the set flow rate. Therefore, the protruding flow rate of the shield gas ejected from the nozzle 21 of the welding torch 20 can be reduced. Therefore, waste of shield gas can be suppressed with a simple configuration, and the amount of shield gas consumed can be reduced.

  Further, in the present embodiment, it is only necessary to add tubes 61 on the upstream side and the downstream side of the gas valve 30 with respect to the conventional consumable electrode type arc welding apparatus that does not include the shield gas flow rate control means 60. For example, a general-purpose tube that is generally available can be used as it is, and there is no need to manufacture a dedicated product. Therefore, implementation is very easy and it can be implemented at low cost.

  In the above embodiment, the tubes 61 are provided on both the upstream side and the downstream side of the gas valve. However, if the protruding flow rate can be reduced, the tube 61 may be provided on either the upstream side or the downstream side. Is possible. In the first embodiment, the case where the shield gas flow rate control means 60 is configured by the tube 61 has been described as an example. However, an orifice that restricts the flow rate of the shield gas flowing in the shield gas flow path 31 is configured. What is necessary is not limited to the tube.

  FIG. 4 is a graph showing a change in the flow rate of the shield gas, and FIG. 4A is a graph showing a change in the flow rate of the shield gas in the consumable electrode arc welding apparatus 1 according to the present embodiment. ) Is a graph showing a change in the flow rate of the shield gas when the tube 61 is removed from the consumable electrode arc welding apparatus 1. In the figure, the area indicated by hatching a is the set flow rate, and the area indicated by hatching b is the protruding flow rate.

  Here, the original pressure of the shield gas supplied from the shield gas supply source 5 is 0.3 megapascal, the inner diameters of the gas hoses 32 and 33 are 6 mm, the inner diameter of the tube 61 is 1.5 mm, and the length of the tube 61 is 40 mm, the length of the shield gas flow path 31 was 200 meters, and the protruding flow rate of the shield gas was measured for 0.05 minutes from when the gas valve 30 was opened.

  As a result, when the tube 61 was removed, the protruding flow rate was 2.0 liters, whereas with the tube 61, the protruding flow rate was 0.95 liters, which was reduced to about a half. .

  Therefore, by providing the tube 61, when the gas valve 30 is opened, it is possible to suppress the flow rate of the shield gas passing through the shield gas flow path 31 from being temporarily increased from the set flow rate. We can see that we were able to reduce it.

(Second Embodiment)
FIG. 5 is a diagram for explaining the configuration of the shield gas flow rate control means 60 of the consumable electrode arc welding apparatus 1 according to the second embodiment, and FIG. 6 shows the configuration of the shield gas flow rate control means 60 in the second embodiment. It is sectional drawing explaining the structure of the chamber 62 to do. In addition, the same code | symbol is attached | subjected to the component similar to 1st Embodiment, and the detailed description is abbreviate | omitted.

  What is characteristic in the second embodiment is that the tube 61 on the downstream side of the tubes 61 provided on the upstream side and the downstream side of the gas valve 30 in the first embodiment is changed to the chamber 62. is there.

  As shown in FIG. 5, the chamber 62 is provided in the middle of the gas hose 33. As shown in FIG. 6, the chamber 62 has a cylindrical body portion 62a having a predetermined volume space inward. When the gas valve 30 is opened, the predetermined volume space is reduced in the chamber 62 after the pressure of the shield gas flowing into the chamber 62 from the upstream side of the shield gas channel 31 is reduced. It is set to a size having a so-called damper effect that can be sent to the side.

  Tubular connection portions 62d and 62e are projected at the center positions of the pair of end plates 62b and 62c that close both axial sides of the body portion 62a, and are provided upstream and downstream of the gas hose 33, respectively. Each of them is connected so that the shielding gas can be introduced into the chamber 62 and discharged from the chamber 62.

  The outer diameters of the connecting portions 62d and 62e are formed such that the end portions of the gas hose 33 can be externally fitted and connected. Further, the inner diameters of the connecting portions 62d and 62e are set to be smaller than the inner diameter of the gas hose 33 and to have a size constituting an orifice that restricts the flow rate of the shield gas passing through the connecting portions 62d and 62e. In the present embodiment, it is set to the same size as the inner diameter of the tube 61 on the upstream side.

  According to the consumable electrode arc welding apparatus 1 having the chamber 62, when the valve control means 50 receives the arc welding start command and opens the gas valve 30, it flows into the chamber 62 from the upstream side of the shield gas flow path 31. The shield gas can be expanded in the chamber 62 and the pressure of the shield gas can be reduced in the chamber 62 before being sent out downstream of the shield gas flow path 31.

  Accordingly, the pressure difference between the upstream side and the downstream side of the shield gas channel 31 can be absorbed by the chamber 62, and the shield gas can be prevented from flowing into the downstream side of the shield gas channel 31 at a stretch. Therefore, when the gas valve 30 is opened, it is possible to suppress the flow rate of the shield gas passing through the shield gas flow path 31 from temporarily increasing above the set flow rate, and to reduce the protruding flow rate. Therefore, waste of shield gas can be suppressed with a simple configuration, and the amount of shield gas consumed can be reduced.

  Further, the flow rate of the shielding gas can be reduced by the connecting portion 62d, expanded in the chamber 62, can be reduced again by the connecting portion 62e, can be expanded in the gas hose 33 after passing through the connecting portion 62e, and the shield passing through the chamber 62. The gas flow rate can be reduced overall. Therefore, the protruding flow rate of the shield gas can be further reduced.

  Further, this embodiment adds a chamber 62 downstream of the gas valve 30 and a tube 61 upstream of the gas valve 30 with respect to a conventional consumable electrode arc welding apparatus that does not include the shield gas flow rate control means 60. It is only necessary to add, and implementation is extremely easy and can be implemented at low cost.

  In the second embodiment described above, the inner diameters of the connection portions 62d and 62e are set to be smaller than the inner diameter of the shield gas flow path 31, and the connection portions 62d and 62e constitute an orifice for restricting the shield gas. Although the case has been described as an example, the inner diameters of the connecting portions 62d and 62e may be set equal to the inner diameters of the gas hoses 32 and 33 of the shield gas passage 31. According to this, the shield gas that has flowed into the chamber 62 through the connecting portion 62d can be expanded in the chamber 62, and the pressure of the shield gas can be reduced. The pressure difference on the side can be reduced to prevent the shield gas from flowing into the downstream side of the shield gas passage 31 at a stretch, and the protruding flow rate of the shield gas can be reduced.

(Third embodiment)
FIG. 7 is a diagram for explaining the configuration of the shield gas flow rate control means 60 of the consumable electrode arc welding apparatus 1 according to the third embodiment. FIG. 8 is a timing for opening and closing the gas valve 30 and the bypass valve 64 by the valve control means 50. It is a time chart explaining. In addition, the same code | symbol is attached | subjected to the component similar to 1st Embodiment, and the detailed description is abbreviate | omitted.

  What is characteristic in the third embodiment is that the shield gas flow rate control means 60 has a bypass passage 63 that bypasses the gas valve 30 and a bypass passage 63 that has a smaller flow area than the gas valve 30 and bypasses the bypass passage 63. A bypass valve 64 for opening and closing the passage 63 is provided, and the valve control means 50 opens and closes the gas valve 30 and the bypass valve 64 at a predetermined timing.

  The bypass passage 63 has the same inner diameter as the gas hoses 32 and 33, and as shown in FIG. 8, the upstream end is connected to branch from the gas hose 32, and the downstream end is connected to join the gas hose 33. The gas valve 30 is bypassed.

  The bypass valve 64 is provided in the middle of the bypass passage 63 and has a smaller flow area than the gas valve 30. The valve control means 50 is opened and closed to communicate and block the upstream side and the downstream side of the bypass passage 63.

  When the valve control unit 50 receives an arc welding start command from the robot control unit 14, the valve control unit 50 first opens the bypass valve 64. For example, the time from when the bypass valve 64 is opened until the pressure on the downstream side of the shield gas passage 31 rises to some extent, or the shield gas that passes through the shield gas passage 31 after the bypass valve 64 is opened. The control program is set so that the gas valve 30 is opened after a preset time has elapsed since the bypass valve 64 is opened, such as the time until the flow rate of the gas converges to the set flow rate. In the present embodiment, the time from when the bypass valve 64 is opened until the flow rate of the shield gas passing through the shield gas flow path 31 converges to the set flow rate is set as a preset time. Further, as shown in FIG. 8, after a predetermined time has elapsed since the bypass valve 64 is opened, the bypass valve 64 is closed and the gas valve 30 is opened.

  According to the consumable electrode type arc welding apparatus 1 having the above-described configuration, when the valve control unit 50 receives an arc welding start command from the robot control unit 14, first, the bypass valve 64 is opened. Therefore, the shield gas passes through the bypass valve 64 having a channel area smaller than the channel area of the shield gas channel 31, and the flow rate of the shield gas flowing into the downstream side of the bypass valve 64 is reduced. Therefore, when the bypass valve 64 is opened, the shield gas can be prevented from flowing from the upstream side to the downstream side of the bypass passage 63 at a stretch, and the protruding flow rate can be reduced.

  Then, for example, when the pressure on the downstream side of the shield gas passage 31 rises to some extent due to the opening operation of the bypass valve 64, or when the shield gas protruding flow rate due to the opening operation of the bypass valve 64 is complete, the bypass valve The gas valve 30 is opened after a predetermined time has elapsed since the opening 64 is opened.

  Therefore, when the gas valve 30 is opened, the shield gas can be prevented from flowing all at once, and the flow rate of the shield gas passing through the shield gas channel 31 is prevented from temporarily increasing above the set flow rate. In addition, the protruding flow rate can be reduced. Therefore, it is possible to reduce the consumption of the shield gas by suppressing the waste of the shield gas with a simple configuration.

  Further, the bypass passage 63 and the bypass valve 64 can be easily retrofitted to a conventional consumable electrode arc welding apparatus that does not include the shield gas flow rate control means 60, and the control program of the valve control means 50 is also simple. Therefore, implementation is extremely easy.

  In the third embodiment described above, the bypass valve 64 is opened, and after a predetermined time has elapsed, the bypass valve 64 is closed and the gas valve 30 is opened. However, the present invention is not limited thereto. The timing at which the bypass valve 64 is closed and the timing at which the gas valve 30 is opened can be arbitrarily set so that the protruding flow rate is reduced.

(Fourth embodiment)
FIG. 9 is a diagram illustrating the configuration of the shield gas flow rate control means 60 of the consumable electrode arc welding apparatus 1 according to the fourth embodiment. In addition, the same code | symbol is attached | subjected to the component similar to 1st Embodiment, and the detailed description is abbreviate | omitted.

  What is characteristic in the fourth embodiment is that a chamber 65 constituting the shield gas flow rate control means 60 is added to the downstream side of the shield gas flow path 31 in the third embodiment.

  As shown in FIG. 9, the chamber 65 is provided at an intermediate position of the gas hose 33 so that the downstream end of the bypass passage 63 is located on the downstream side of the portion joined and connected to the shield gas flow path 31. .

  The chamber 65 has a cylindrical body 65a having a predetermined volume space on the inner side. The predetermined volume space reduces the pressure of the shield gas flowing into the chamber 62, and then the shield gas flow. It is set to a size that can be sent to the downstream side of the path 31.

  Tubular connection portions 65d and 65e project from the center positions of the pair of end plates 62b and 62c that close both axial sides of the body 65a, and are connected to the upstream side and the downstream side of the gas hose 33, respectively. Thus, the shielding gas can be introduced into the chamber 62 and discharged from the chamber 62.

  The outer diameters of the connecting portions 65d and 65e are formed such that the end portions of the gas hose 33 can be externally fitted and connected. Further, the inner diameters of the connecting portions 65d and 65e are set to be approximately the same as the inner diameter of the gas hose 33.

  According to the consumable electrode arc welding apparatus 1 having the above-described configuration, when the gas valve 30 or the bypass valve 64 is opened, the shield gas that has flowed into the chamber 65 is expanded in the chamber 65 so that the pressure of the shield gas is increased. After being lowered, it can be sent to the downstream side of the shield gas passage 31.

  Therefore, the pressure difference between the upstream side and the downstream side of the shield gas flow path 31 is absorbed by the chamber 65 to prevent the shield gas from flowing into the downstream side of the shield gas flow path 31 when the gas valve 30 is opened. Can do. Therefore, when the gas valve 30 is opened, the flow rate of the shield gas passing through the shield gas flow path 31 can be suppressed from temporarily increasing above the set flow rate, and the protruding flow rate can be reduced. Therefore, it is possible to reduce the consumption of the shield gas by suppressing the waste of the shield gas with a simple configuration.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the first to fourth embodiments described above, the case where the present invention is applied to the consumable electrode type arc welding apparatus 1 has been described as an example, but general welding apparatuses using shield gas such as a non-consumable arc welding apparatus or a laser welding apparatus. It is possible to apply to. Furthermore, in the above-described first to fourth embodiments, the case of the configuration having the robot arm 10 has been described as an example. However, the present invention may be applied to a manual welding apparatus in which an operator operates the welding torch 20 to perform arc welding. Good.

1 is an overall view of a consumable electrode arc welding apparatus according to a first embodiment. It is a figure which expands and shows the A section of FIG. It is sectional drawing explaining the structure of the tube which comprises a shield gas flow control means. It is a graph which shows the change of the flow volume of shielding gas. It is a figure explaining the structure of the shield gas flow control means of the consumable electrode type arc welding apparatus concerning 2nd Embodiment. It is sectional drawing explaining the structure of the chamber which comprises a shield gas flow control means. It is a figure explaining the structure of the shield gas flow control means of the consumable electrode type arc welding apparatus concerning 3rd Embodiment. It is a time chart explaining the opening / closing timing of a gas valve and a bypass valve. It is a figure explaining the structure of the shield gas flow control means of the consumable electrode type arc welding apparatus concerning 4th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Consumable electrode type arc welding apparatus 5 Shield gas supply source 20 Welding torch 30 Gas valve 31 Shield gas flow path 50 Valve control means 60 Shield gas flow rate control means 61 Tube 62 Chamber 63 Bypass passage 64 Bypass valve 65 Chamber

Claims (5)

In the welding apparatus for ejecting the shield gas from the welding torch by opening and closing operation of a gas valve provided in the middle position of the shield gas flow path communicating between the shield gas supply source and the welding torch,
Shield gas flow rate control means for suppressing the flow rate of the shield gas flowing from the upstream side to the downstream side in the shield gas flow path from temporarily increasing above a preset flow rate by opening the gas valve Is provided in the middle of the shield gas flow path. The shield gas flow rate control means includes:
A midway position of the shield gas flow path upstream of the gas valve and a midway position of the shield gas flow path downstream of the gas valve having a flow path area smaller than the flow path area of the shield gas flow path. The welding apparatus according to claim 1, wherein the welding apparatus is configured by an orifice provided at least on one side. The shield gas flow rate control means includes:
A midway position of the shield gas flow path upstream of the gas valve and a midway position of the shield gas flow path downstream of the gas valve having a flow path area smaller than the flow path area of the shield gas flow path. The welding apparatus according to claim 1, comprising a tube provided on at least one side. The shield gas flow rate control means includes:
The welding apparatus according to claim 1, wherein the welding apparatus is configured by a chamber having a predetermined volume space and provided at a midway position of a shield gas flow path downstream of the gas valve. The shield gas flow rate control means includes:
A bypass flow path having an upstream end connected to a shield gas flow path upstream of the gas valve and a downstream end connected to a shield gas flow path downstream of the gas valve to bypass the gas valve;
A bypass valve provided in the flow path of the bypass passage and having a flow area smaller than the flow area of the shield gas flow path to open and close the bypass flow path;
Valve control means for opening the bypass valve and opening the gas valve after a preset time has elapsed since the opening operation;
The welding apparatus according to claim 1, comprising:

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