CN111496358A

CN111496358A - Narrow-gap tungsten electrode argon arc welding gun

Info

Publication number: CN111496358A
Application number: CN202010480542.9A
Authority: CN
Inventors: 贾传宝; 张治卫
Original assignee: Shandong Pingyun Intelligent Equipment Co ltd
Current assignee: Shandong Pingyun Intelligent Equipment Co ltd; Shandong University
Priority date: 2020-05-30
Filing date: 2020-05-30
Publication date: 2020-08-07

Abstract

The invention relates to a narrow-gap argon tungsten-arc welding gun, which belongs to the technical field of narrow-gap welding equipment and comprises a gun barrel, wherein an upper cover plate and a lower cover plate are arranged at two ends of the gun barrel; a water cooling sleeve is arranged in the gun barrel, the main shaft penetrates through the water cooling sleeve, and a water inlet pipe and a water return pipe on the water cooling sleeve penetrate through the upper cover plate to be connected with an external water cooling system; a conductive sliding block is arranged in the gun barrel, the main shaft penetrates through the conductive sliding block, and a lead on the conductive sliding block penetrates through the upper cover plate to be connected with an external welding power supply; the upper cover plate is provided with an air tap connector in a penetrating mode, the air tap connector is connected with an external protective gas system through an air inlet pipe, the lower cover plate is provided with an air outlet hole in a penetrating mode, the outer portion of the gun barrel is provided with a shell, and the gun barrel and the shell move relatively. The tungsten electrode of the structure of the invention has higher coaxiality, small swing, longer extension distance, reliable contact of the conductive sliding block and strong conductive capability, and can realize thick plate and narrow gap welding.

Description

Narrow-gap tungsten electrode argon arc welding gun

Technical Field

The invention relates to a narrow-gap argon tungsten-arc welding gun, belonging to the technical field of narrow-gap welding equipment.

Background

The thick plate workpiece is welded by groove welding. The groove can be filled with the welding seam only by adopting multi-pass and multi-layer welding. If narrow gap welding without beveling is adopted, the welding workload is obviously reduced. The welding gun is one of the difficulties in limiting the development of narrow gap welding, the diameter of a protective nozzle of the existing welding gun is much larger than the distance between grooves of the narrow gap welding, the thickness of a workpiece is the depth of the groove, and the existing welding gun cannot penetrate into a narrow gap for welding.

Narrow Gap Welding (NGW) is mainly applied to thick plate welding, and before welding, a welding interface is not beveled or beveled at a small angle, and a narrow and deep gap is reserved. And (3) welding the whole welding seam with high efficiency by adopting a consumable electrode or non-consumable electrode method. Narrow gap welding has the following advantages: the narrower welding line can greatly reduce the consumption of filling metal and reduce the cost of raw materials; the welding heat input quantity is low, the heat affected zone is narrow, and the mechanical strength performance of the welding joint is good; small deformation, small residual stress, excellent mechanical property and easy control of shape; the production efficiency is high, and can be more than 2 times higher than that of the traditional method. Based on the advantages, the narrow gap welding technology is highly concerned by welding experts of various countries, and the narrow gap welding is widely applied to the manufacturing industry nowadays.

According to the definition of narrow gap welding by the eighth committee on the research and development committee of pressure vessels of japan in the 80 th century, the plate thickness is 30mm or more, and welding is performed with a gap smaller than the plate thickness. When the thickness is less than 200mm, the gap is less than 20mm, and when the thickness exceeds 200mm, the gap is less than 30 mm. For a conventional thick plate (about 30 mm), the groove size is a narrow gap below 8mm, and an ultra-narrow gap below 5 mm.

The narrow gap welding technology mainly comprises narrow gap argon tungsten-arc welding (NG-TIG), narrow gap gas metal arc welding (NG-GMAW), narrow gap submerged arc welding (NG-SAW) and narrow gap laser welding (NG-L BW).

At present, the main realization mode of narrow-gap argon arc welding is a tungsten electrode swinging mode.

In the practical application process, the gap size and the depth size of other narrow gap welding are affected, and welding of an ultra-thick plate and a narrow gap mode cannot be achieved. For example, the thickness can be only below 100mm at most, the gap can be close to 20mm at most, and the groove is required to be opened.

The invention content is as follows:

aiming at the defects of the prior art, the invention provides a narrow-gap argon tungsten-arc welding gun, which adopts a non-axisymmetric rotating tungsten electrode mode to weld an ultra-thick plate (0-300mm) and a narrow gap (4-10 mm).

The technical scheme of the invention is as follows:

a narrow-gap tungsten electrode argon arc welding gun comprises a gun barrel, wherein the gun barrel is a cavity with two open ends, an upper cover plate is arranged on the upper side of the gun barrel, a lower cover plate is arranged on the lower side of the gun barrel, a fixing plate is arranged in the gun barrel, a motor is arranged on the fixing plate, an output shaft of the motor is connected with a main shaft, and the tail end of the main shaft is connected with a tungsten electrode;

a water cooling sleeve is arranged in the gun barrel, the main shaft penetrates through the water cooling sleeve, a water inlet pipe and a water return pipe are arranged on the water cooling sleeve, and the water inlet pipe and the water return pipe penetrate through the upper cover plate and are connected with an external water cooling system; cooling liquid is input into the water inlet pipe, cooling liquid is output from the water outlet pipe, water circulation is completed, the temperature of the main shaft is reduced through the circulation process of water, and long-time work of the welding gun is achieved;

a conductive sliding block is arranged in the gun barrel, the main shaft penetrates through the conductive sliding block, a lead is arranged on the conductive sliding block, and the lead penetrates through the upper cover plate to be connected with an external welding power supply; the main shaft is effectively conducted through the communication of a lead and a welding power supply, the conductive sliding block is matched with the main shaft and rotates relatively, and the conductive sliding block is fixed when the main shaft rotates;

the upper cover plate is provided with an air nozzle joint in a penetrating manner, the air nozzle joint is connected with an external protective gas system through an air inlet pipe, the lower cover plate is provided with an air outlet hole in a penetrating manner, the air nozzle joint, the upper cover plate, a cavity in the gun barrel, a main shaft and the lower cover plate jointly form a gas channel, external protective gas enters the gun barrel from the air nozzle joint, the gun barrel is filled firstly, a buffering effect is achieved, then a welding gun is uniformly and stably discharged from the air outlet hole of the lower cover plate, blown gas belongs to laminar flow, directivity is consistent, a molten pool under the electric arc is intensively protected, a restraining effect is achieved on the welding electric arc, arc starting and stable welding processes are guaranteed, arc starting above the side wall is prevented, the protective gas provides protective gas for the molten pool and a welding seam at;

the outside of the gun barrel is provided with a shell, and the gun barrel and the shell move relatively.

The upper cover plate is fixed at the upper end of the gun barrel, and is provided with threads or mechanical mounting hole positions, so that the upper cover plate can be respectively matched with the gun barrel and other parts of an assembling machine to form a gas passage; the lower cover plate is fixed at the lower end of the gun barrel, is provided with threads or mechanical mounting hole positions, is beneficial to the assembly machine matching with the gun barrel and other parts respectively, and is provided with a certain number of air outlet holes so as to be beneficial to the smooth and uniform discharge of air.

The shell is positioned at the outermost side and is a cylindrical object with a circular or other cross section.

Preferably, the output shaft of the motor is connected with the main shaft through a coupling.

Preferably, the wire is connected with the conductive slider through a mechanical fastener, and the mechanical fastener comprises a bolt, an elastic gasket and a flat gasket.

Preferably, still be equipped with temperature measuring resistor through structures such as bolt on the electrically conductive slider, temperature measuring resistor's sensing line runs through the upper cover plate and is connected with external equipment controller, the inside temperature of real-time measurement welder to follow-up control prevents that the high temperature welder from damaging.

Preferably, at least two bearings are arranged between the main shaft and the inner wall of the gun barrel. The main shaft is assembled inside the gun barrel through a bearing, so that the welding gun can rotate stably during working.

Further preferably, a positioning sloping platform is arranged on the main shaft, a wall surface matched with the positioning sloping platform is arranged on the inner wall of the conductive sliding block, and a spring is arranged above the conductive sliding block and sleeved on the main shaft. The conductive sliding block penetrates through and positions the main shaft, the main shaft and the conductive sliding block are conveniently clamped and fixed through the positioning inclined table, and the spring can further reinforce the close connection between the conductive sliding block and the main shaft in the axial direction.

Further preferably, the contact area of the main shaft and the conductive slider is at least 200mm². The conical surface is arranged on the positioning sloping platform to ensure the contact stability and increase the contact area so as to avoid serious heating caused by large resistance when the area is too small.

Further preferably, spring overcoat is all equipped with to spring upper end, lower extreme, and the spring overcoat is the ring board, and ring board neighboring is equipped with the round baffle, and the spring overcoat is used for injecing the spring shape, in order to avoid the spring to warp or produce the displacement in compression process, can reduce the frictional force of spring and electrically conductive slider, bearing simultaneously. The spring outer sleeve at the upper end is contacted with the lower end of the bearing, the spring outer sleeve at the lower end is contacted with the conductive sliding block, and the conductive sliding block (9) is tightly matched with the main shaft (11) through the pressure of the compression spring.

Further preferably, the conductive sliding block is a carbon brush, a carbon brush form can be adopted, radial springs are further arranged on the lateral side of the conductive sliding block, the number of the radial springs is at least two, the radial springs are uniformly distributed on the periphery of the spindle, one end of each radial spring is in contact with the tail end of the carbon brush, the other end of each radial spring is in contact with the inner wall of the carbon brush bin, and the spring limiting device is used for fixing the position of the. The conductive sliding block or the carbon brush is further positioned by the radial spring to be tightly matched with the main shaft.

Preferably, the number of the air outlet holes of the lower cover plate is at least two, and the air outlet holes are uniformly distributed on the lower cover plate.

Further preferably, the number of the air outlet holes is 4.

Further preferably, the end of the gun barrel is provided with an air guide nozzle, the inside of the air guide nozzle is inverted cone-shaped, and the inner side wall of the air guide nozzle is provided with a thread groove. The trend of the protective airflow is further restrained by the air guide nozzle.

Preferably, the upper end and the lower end of the inner wall, which is in contact with the main shaft, of the water cooling jacket are provided with sealing rings, the main shaft and the water cooling jacket are combined in a rotary dynamic sealing mode, a sealing cavity is formed among the main shaft, the water cooling jacket and the sealing rings, the sealing cavity is annular, the water inlet pipe is communicated with the annular sealing cavity, the water return pipe is communicated with the annular sealing cavity to form a closed loop together, cooling water enters the water cooling jacket and then cools the main shaft, and the sealing rings can further prevent the cooling water from overflowing.

Preferably, the tail end of the main shaft is provided with a step hole, a tungsten electrode clamp is arranged in the step hole, a tungsten electrode is fixedly arranged in the tungsten electrode clamp, and the tungsten electrode clamp is connected with the main shaft through a tungsten electrode clamp locking nut. The tungsten electrode clamp locking nut is used for fastening the tungsten electrode clamp, so that the tungsten electrode is fastened. The tungsten electrode clamp is fixed on the main shaft through a tungsten electrode clamp locking nut, and the tungsten electrode is in effective contact with the main shaft, the tungsten electrode clamp and the tungsten electrode clamp locking nut, is positioned and locked, is coaxial with the main shaft and rotates synchronously.

Further preferably, the cross section of the stepped hole is one of a circle, an ellipse, a cone, a quadrangle, a triangle and a polygon. The cross section area of the matching surface between the main shaft and the tungsten electrode clamp can be circular or other shapes, and the shapes of the main shaft and the tungsten electrode clamp are matched.

Further preferably, the matching surface between the tungsten electrode clamp and the tungsten electrode clamp locking nut is circular or conical.

Preferably, the relative movement between the gun barrel and the shell is a transmission gear or a ball screw pair;

when the gun barrel is connected with the shell through the transmission gear, the outer wall of the gun barrel is provided with a rack structure, the inner wall of the shell is provided with a gear, and the gear is meshed with the rack; the gear rotates to drive the gun barrel to vertically displace in the shell;

when being connected through the ball screw pair between barrel and the shell, the shell inner wall is equipped with the lead screw, is equipped with ball slider on the lead screw, and ball slider and barrel outer wall connection, the rotation of lead screw drive ball slider rectilinear movement to drive barrel vertical movement in the shell.

When welding, the shell keeps a certain distance with the surface of a workpiece, and the gun barrel main body moves up and down freely so as to realize welding of different welding layers of the same welding line.

The invention has the beneficial effects that:

according to the technical scheme, the narrow-gap U-shaped groove (or no groove) with the width of 4-10mm is machined, so that the thick plate and the large thick plate are welded with high quality and high efficiency. Compared with a narrow-gap consumable electrode and a submerged arc welding method, the method has the advantages that welding heat input is reduced, high welding quality is guaranteed, groove machining area can be reduced, cladding metal filling efficiency is improved, and welding efficiency is improved to a certain extent. Compared with the common tungsten electrode argon arc welding, the thickness of the weldable plate, the production efficiency and the production quality are greatly increased.

The tungsten electrode of the invention has higher coaxiality, small swing, longer extension distance, reliable contact of the conductive sliding block and strong conductive capability. The maximum current born by a proper tungsten electrode can reach 550A, and the unilateral jumping can reach within 0.5mm or even lower when the extending distance is 150 mm. The device has long extending distance, small swing and large load current, so that the device can realize thick plate (for example, 0-300mm) and narrow gap (for example, 4-10mm) welding. The groove opening is reduced or even not required, so that a large amount of working hours and material cost for processing and welding can be saved; meanwhile, the gas protection effect of argon and the like is obvious, and the chemical components and the mechanical property of the welding line are stable.

The gas passage at the center of the welding gun can well protect a molten pool and a welding seam, and higher welding seam quality is obtained. The combined action of water cooling and air cooling can reduce the temperature of each part of the welding gun, so that the welding gun can work for a long time and provide larger temporary loading rate.

Drawings

FIG. 1 is a schematic cross-sectional view of a narrow gap argon tungsten-arc welding gun according to a preferred embodiment of the present invention.

FIG. 2 is a schematic top view of a narrow gap argon tungsten-arc welding gun according to a preferred embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view of a water-cooling part of a narrow gap argon tungsten-arc welding gun according to a preferred embodiment of the present invention.

FIG. 4 is a schematic diagram of a partial cross-sectional structure of a conductive slider according to a preferred embodiment of the narrow gap argon tungsten-arc welding gun of the present invention.

FIG. 5 is a schematic diagram of a tungsten electrode tip portion of a narrow gap argon tungsten arc welding gun according to a preferred embodiment of the present invention, α is 45 °.

Fig. 6 is a schematic view of a carbon brush structure according to the present invention.

The labels used in the figures are as follows: (1) the device comprises a gun barrel, (2) a water inlet pipe, (3) a lead, (4) an air tap joint, (5) a fixing plate, (6) a water return pipe, (7) a motor, (8) a bearing and a positioning piece thereof, (9) a conductive sliding block, (10) a water cooling jacket, (11) a spindle, (12) a tungsten electrode clamp, (13) a tungsten electrode clamp locking nut, (14) a tungsten electrode, (15) an upper cover plate, (16) a lower cover plate, (17) a bearing, (18) a coupler, (19) a spring, (20) a sealing ring, (21) a bolt, (22) an elastic gasket, (23) a flat gasket, (24) a gear, (25) a shell, (26) a spring outer sleeve, (27) a temperature measuring resistor, (28) a carbon brush and (29) a carbon brush bin.

Detailed Description

The present invention will be further described by way of examples, but not limited thereto, with reference to the accompanying drawings.

The following examples are only for illustrating the technical solutions of the present invention more clearly, and should not be construed as limiting the scope of the present invention.

Although relative terms such as "upper" and "lower" are used in this specification to describe one component of an icon relative to another component, these terms are used in this specification for convenience only. If the device of the icon is turned upside down, the component described as "upper" will become the component "lower". When a structure is "on" another structure, it may mean that the structure is integrally formed with the other structure, or that the structure is "directly" disposed on the other structure, or that the structure is "indirectly" disposed on the other structure via another structure. The terms "a", "an", "the" and "the" are used to indicate the presence of one or more elements/components/parts/etc.; the terms "comprising" and "having" are intended to be inclusive and mean that there may be additional elements/components/etc. other than the listed elements/components/etc

Example 1:

the utility model provides a narrow clearance tungsten utmost point argon arc welder, including a gun section of thick bamboo, a gun section of thick bamboo is both ends open-ended cavity, a gun section of thick bamboo upside is equipped with the upper cover plate, a gun section of thick bamboo downside is equipped with down the apron, the upper cover plate, lower apron is fixed in the upper and lower both ends of a gun section of thick bamboo respectively through other modes such as screw thread or bolt, be equipped with the fixed plate in the gun section of thick bamboo, be equipped with the motor on the fixed plate, the motor output shaft passes through the shaft coupling and links to each other with the main shaft, the main shaft end links to each other with the tungsten utmost point.

A water cooling sleeve is arranged in the gun barrel, the main shaft penetrates through the water cooling sleeve, a water inlet pipe and a water return pipe are arranged on the water cooling sleeve, and the water inlet pipe and the water return pipe penetrate through the upper cover plate to be connected with an external water cooling system.

A conductive sliding block is arranged in the gun barrel, the main shaft penetrates through the conductive sliding block, a lead is arranged on the conductive sliding block, and the lead penetrates through the upper cover plate to be connected with an external welding power supply; the main shaft is effectively conducted through the communication of the conducting wire and the welding power supply, the conducting sliding block is matched with the main shaft and rotates relatively, and the conducting sliding block is fixed when the main shaft rotates.

The upper cover plate is provided with an air nozzle joint in a penetrating way, the air nozzle joint is connected with an external protective gas system through an air inlet pipe, the lower cover plate is provided with an air outlet in a penetrating way, the air nozzle joint, the upper cover plate, the inner cavity of the gun barrel, the main shaft and the lower cover plate form a gas channel together, external protective gas enters the gun barrel from the air nozzle joint and is uniformly and stably discharged out of the welding gun from the air outlet of the lower cover plate, the protective gas not only provides protective gas for a welding pool and a welding seam at a welding position, but also cools the inner part of;

The upper cover plate is fixed at the upper end of the gun barrel, and is provided with threads or mechanical mounting hole positions, so that the upper cover plate can be respectively matched with the gun barrel and other parts of an assembling machine to form a gas passage; the lower cover plate is fixed at the lower end of the gun barrel, is provided with threads or mechanical mounting hole positions, is beneficial to the assembly machine matching with the gun barrel and other parts respectively, and is provided with a certain number of air outlet holes so as to be beneficial to the smooth and uniform discharge of air. The water cooling jacket can effectively cool the temperature rise of the welding gun caused by welding heat conduction and electric conduction heating; the gas circuit in the welding gun provides protective gas for welding and simultaneously cools the interior of the gun body.

The outer shell is positioned at the outermost side and is a cylindrical object with a circular or other shapes such as a rectangular, oval and polygonal section.

Example 2:

a narrow gap argon tungsten arc welding gun having the structure as set forth in embodiment 1, except that the wire is connected to the conductive slider by a mechanical fastener comprising a bolt, an elastic washer, and a flat washer.

Example 3:

the utility model provides a narrow clearance tungsten utmost point argon arc welder, its structure as embodiment 1, the difference is that still be equipped with temperature measuring resistor through structure such as bolt on the electrically conductive slider, temperature measuring resistor's sensing line runs through the upper cover plate and is connected with external equipment controller, measures the inside temperature of welder in real time to follow-up control prevents that the too high temperature welder from damaging.

Example 4:

a narrow gap argon tungsten-arc welding gun is disclosed in embodiment 1, except that two bearings are disposed between the main shaft and the inner wall of the gun barrel. The main shaft is assembled inside the gun barrel through a bearing, so that the welding gun can rotate stably during working.

Example 5:

the structure of the narrow-gap argon tungsten-arc welding gun is as described in embodiment 4, except that a positioning sloping platform is arranged on a main shaft, a wall surface matched with the positioning sloping platform is arranged on the inner wall of a conductive sliding block, and a spring is arranged above the conductive sliding block and sleeved on the main shaft. The conductive sliding block penetrates through and positions the main shaft, the main shaft and the conductive sliding block are conveniently clamped and fixed through the positioning inclined table, and the spring can further reinforce the close connection between the conductive sliding block and the main shaft in the axial direction.

The contact area between the main shaft and the conductive slide block is at least 200mm². The conical surface is arranged on the positioning inclined table, so that the contact area is increased, and the problems of high resistance and serious heating caused by too small area are avoided.

Example 6:

the utility model provides a narrow clearance tungsten electrode argon arc welder, its structure as embodiment 5, the difference is that spring upper end, lower extreme all are equipped with the spring overcoat, and the spring overcoat is the ring board, and the ring board peripheral border is equipped with the round baffle, and the spring overcoat is used for injecing the spring shape, in order to avoid the spring to produce the displacement at compression in-process both ends, can reduce the frictional force of spring and electrically conductive slider, bearing simultaneously. The spring outer sleeve at the upper end is contacted with the lower end of the bearing, the spring outer sleeve at the lower end is contacted with the conductive sliding block, and the conductive sliding block (9) is tightly matched with the main shaft (11) through the pressure of the compression spring.

Example 7:

the structure of the narrow-gap argon tungsten-arc welding gun is as described in embodiment 6, except that the conductive sliding block is a carbon brush, and a carbon brush form can be adopted, as shown in fig. 6, the side of the welding gun is further provided with at least two radial springs, the radial springs are uniformly distributed on the periphery of the main shaft, one ends of the radial springs are in contact with the tail end of the carbon brush, the other ends of the radial springs are in contact with a spring limiting device, the spring limiting device is used for fixing the position of the spring, for example, the spring limiting device is a cylindrical bin with an opening at one end, the spring is arranged in the cylindrical bin, and the spatial position of the spring and. The conductive sliding block or the carbon brush is further positioned by the radial spring to be tightly matched with the main shaft.

Example 8:

a narrow gap argon tungsten-arc welding gun, the structure of which is as described in embodiment 6, except that the number of the air outlets of the lower cover plate is 4, and the air outlets are uniformly distributed on the lower cover plate.

Example 9:

a narrow gap argon tungsten-arc welding gun is disclosed in embodiment 8, except that a gas nozzle is arranged at the end of the gun barrel, the gas nozzle is in an inverted cone shape, and a thread groove is formed in the inner side wall. The trend of the protective airflow is further restrained by the air guide nozzle.

Example 10:

the narrow-gap argon tungsten-arc welding gun is structurally as described in embodiment 1, except that a stepped hole is formed in the tail end of a main shaft, a tungsten electrode clamp is arranged in the stepped hole, a tungsten electrode is fixedly arranged in the tungsten electrode clamp, and the tungsten electrode clamp is connected with the main shaft through a tungsten electrode clamp locking nut. The tungsten electrode clamp locking nut is used for fastening the tungsten electrode clamp, so that the tungsten electrode is fastened.

The cross section of the stepped hole is circular, and the tungsten electrode clamp is matched with the stepped hole. The matching surface between the tungsten electrode clamp and the tungsten electrode clamp locking nut is circular.

Example 11:

a narrow gap argon tungsten arc welding gun constructed as described in example 10, except that the cross-section of the stepped bore is elliptical and the tungsten electrode holder is fitted thereto.

Example 12:

a narrow gap argon tungsten arc welding gun having the structure as set forth in embodiment 10, except that the cross section of the stepped hole is quadrangular, and the tungsten electrode holder is fitted thereto.

Example 13:

a narrow gap argon tungsten arc welding gun configured as described in example 10, except that the cross-section of the stepped bore is triangular and the tungsten electrode holder is fitted thereto.

Example 14:

a narrow gap argon tungsten arc welding gun configured as described in embodiment 10, except that the mating surface between the tungsten clamp and the clamping nut of the tungsten clamp is conical.

Example 15:

a narrow gap argon tungsten-arc welding gun, having the structure as in embodiment 9, except that the relative movement between the gun barrel and the outer shell is a transmission gear, the gun barrel and the outer shell are connected through the transmission gear, the outer wall of the gun barrel is provided with a rack structure, the inner wall of the outer shell is provided with a gear, and the gear is engaged with the rack; the power device drives the gear to rotate, and the gear rotates to drive the gun barrel to vertically displace in the shell.

Example 16:

a narrow gap argon tungsten-arc welding gun having the structure as in embodiment 15, except that the relative movement between the gun barrel and the housing is realized by a ball screw pair; the shell inner wall is equipped with the lead screw, is equipped with ball slider on the lead screw, ball slider and barrel outer wall connection, and the rotation of lead screw drives ball slider rectilinear movement to drive barrel vertical movement in the shell.

Example 17:

the narrow-gap argon tungsten-arc welding gun is as in embodiment 1, except that sealing rings are arranged at the upper and lower ends of the inner wall of the water cooling sleeve, which is in contact with the main shaft. The cooling water cools the main shaft after entering the water cooling jacket, and the sealing ring can further prevent the cooling water from overflowing.

Comparative example 1

A conventional TIG welding gun comprises a welding gun body, a shunt, a ceramic nozzle, a tungsten electrode clamp, a pressing cap (length division), a microswitch and the like. A maximum thickness of 3mm can be welded.

Comparative example 2

Narrow gap submerged arc welding (NG-SAW) can weld 300mm at the maximum, and conventional welding is 40-50mm thick, and the width of a groove is 18mm or more at the minimum, and the heat input is 15kJ/cm or more without considering the efficiency coefficient. Due to the adoption of the high-power electric arc, the welding line energy of the NG-SAW is increased, the plasticity and the toughness of a welding joint are difficult to improve in a welding state, and the important NG-SAW joint can meet the requirement of service performance by often needing postweld heat treatment. The welding can be carried out only at the spatial positions of flat welding, flat fillet welding and ship-shaped welding.

Comparative example 3

In the narrow-gap gas metal arc welding (NG-GMAW), a welding wire is driven to swing rotationally by a swing mechanism, so that electric arc swing is realized, and fusion of two sides is improved. Due to the limitation of the space of the groove, the gap is large, and the width of the gap is 10mm at least. The swinging melting electrode can be welded to a thickness of more than 100mm, most of the plate thickness is 18-25mm, and the heat input is more than 15 kJ/cm.

Examples of the experiments

By using the welding gun provided by the embodiment 9 of the invention, a tungsten electrode with the diameter of 3.2 specifications is selected, the extending distance of the tungsten electrode is 23mm, the gap width is 6mm, a thick plate with the thickness of 25mm is welded on one side, and the heat input is 12 kJ/cm; selecting a tungsten electrode with the diameter of 6.0 specification, wherein the extending distance of the tungsten electrode is 150mm, the gap width is 10mm, carrying out double-side welding on a thick plate with the thickness of 300mm, and the welding heat input is less than 20 kJ/cm.

Compared with a plurality of welding guns shown in a comparative example, the welding gun disclosed by the invention is used for carrying out narrow gap welding experiments, and as shown in table 1, the welding gun disclosed by the invention is higher in coaxiality, small in swing, longer in extending distance, reliable in contact of a conductive sliding block, strong in conductive capability and large in bearing current, and can realize the narrow gap welding of a thick plate.

TABLE 1 comparison of welding experiments

Case categories	Weldable board thickness (mm)	Whether to groove or not	Minimum clearance (mm)
				Example 9	25	NO (or U type)	6
Example 9	300	NO (or U type)	10
				Comparative example 1	3	NO (OR U, V type)	3
Comparative example 2	300	Is (U, V type)	20
				Comparative example 3	100	Is (U, V type)	20

The patent of the invention and its embodiments have been described above, the description is not limiting, the illustration in the drawings is only one of the embodiments of the invention, and the actual structure is not limited thereto. Those of ordinary skill in the art will understand that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention. In summary, those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiments as a basis for designing or modifying other structures for carrying out the same purposes of the present invention without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A narrow-gap tungsten electrode argon arc welding gun is characterized by comprising a gun barrel, wherein the gun barrel is a cavity with two open ends, an upper cover plate is arranged on the upper side of the gun barrel, a lower cover plate is arranged on the lower side of the gun barrel, a fixing plate is arranged in the gun barrel, a motor is arranged on the fixing plate, an output shaft of the motor is connected with a main shaft, and the tail end of the main shaft is connected with a tungsten electrode;

a water cooling sleeve is arranged in the gun barrel, the main shaft penetrates through the water cooling sleeve, a water inlet pipe and a water return pipe are arranged on the water cooling sleeve, and the water inlet pipe and the water return pipe penetrate through the upper cover plate and are connected with an external water cooling system;

a conductive sliding block is arranged in the gun barrel, the main shaft penetrates through the conductive sliding block, a lead is arranged on the conductive sliding block, and the lead penetrates through the upper cover plate to be connected with an external welding power supply;

the upper cover plate is provided with an air nozzle connector in a penetrating way, the air nozzle connector is connected with an external protective gas system through an air inlet pipe, and the lower cover plate is provided with an air outlet in a penetrating way;

2. The narrow gap argon tungsten-arc welding gun according to claim 1, wherein an output shaft of the motor is connected with the main shaft through a coupling; preferably, at least two bearings are arranged between the main shaft and the inner wall of the gun barrel.

3. The narrow gap argon tungsten arc welding gun according to claim 1, wherein the wire is connected with the conductive slider through a mechanical fastener, and the mechanical fastener comprises a bolt, an elastic gasket and a flat gasket;

preferably, the conductive sliding block is further provided with a temperature measuring resistor, and a sensing wire of the temperature measuring resistor penetrates through the upper cover plate to be connected with an external equipment controller.

4. The narrow gap argon tungsten-arc welding gun according to claim 1, wherein the main shaft is provided with a positioning ramp, the inner wall of the conductive slider is provided with a wall surface matched with the positioning ramp, a spring is arranged above the conductive slider, and the spring is sleeved on the main shaft;

preferably, the contact area of the main shaft and the conductive slider is at least 200mm²；

Further preferably, spring jackets are arranged at the upper end and the lower end of the spring, the spring jackets are circular ring plates, a circle of baffle is arranged on the peripheral edge of each circular ring plate, the spring jacket at the upper end is in contact with the lower end of the bearing, and the spring jacket at the lower end is in contact with the conductive sliding block.

5. The narrow gap argon tungsten arc welding gun according to claim 1, wherein the conductive slider is a carbon brush, the side of the conductive slider is further provided with at least two radial springs, the radial springs are uniformly distributed on the circumference of the spindle, one end of each radial spring is in contact with the tail end of the carbon brush, the other end of each radial spring is in contact with a spring limiting device, and the spring limiting device is used for fixing the position of the spring.

6. The narrow gap argon tungsten-arc welding gun according to claim 1, wherein the number of the air outlet holes of the lower cover plate is at least two, and the air outlet holes are uniformly distributed on the lower cover plate;

preferably, the number of the air outlet holes is 4.

7. The narrow gap argon tungsten-arc welding gun according to claim 1, wherein the end of the gun barrel is provided with a gas nozzle, the inside of the gas nozzle is inverted cone-shaped, and the inner side wall is provided with a thread groove.

8. The narrow gap argon tungsten arc welding gun according to claim 1, wherein the water cooling jacket and the main shaft contact the inner wall of which the upper and lower ends are provided with the sealing rings, the main shaft, the water cooling jacket and the sealing rings jointly form a sealing cavity, the sealing cavity is annular, the water inlet pipe is communicated with the annular sealing cavity, and the water return pipe is communicated with the annular sealing cavity.

9. The narrow gap argon tungsten-arc welding gun according to claim 1, wherein the end of the main shaft is provided with a step hole, a tungsten electrode clamp is arranged in the step hole, a tungsten electrode is fixedly arranged in the tungsten electrode clamp, and the tungsten electrode clamp is connected with the main shaft through a tungsten electrode clamp locking nut;

preferably, the cross section of the stepped hole is one of a circle, an ellipse, a cone, a quadrangle, a triangle and a polygon;

10. The narrow gap argon tungsten arc welding gun according to claim 1, wherein the relative movement between the gun barrel and the outer shell is a transmission gear or a ball screw pair;

when the gun barrel is connected with the shell through the ball screw pair, the inner wall of the shell is provided with a screw, the screw is provided with a ball slide block, and the ball slide block is connected with the outer wall of the gun barrel.