JPS6142682Y2 - - Google Patents

Description

[Detailed description of the invention] This invention can be used for welding in narrow places, especially in places so narrow that it is impossible to install a shield cup (also called a gas nozzle) long enough to ensure an undisturbed shielding gas flow. Regarding useful TIG welding torches.

An example of welding in a narrow space is the welding of impellers used in compressors, blowers, etc. The impeller W has blades 2 of a constant curvature sandwiched between opposing annular horizontal plates 1 and welded to the blades 2. One welding method used for this welding is shown in FIGS. 1 and 2. In this welding method, the temporarily attached impeller W is fixed on a table so that the center of curvature a of the blade 2 to be welded coincides with the rotation center of a table (not shown), and the impeller W is fixed on the table by rotation of the table. The impeller W, which is a material, is a
Fillet welding of the horizontal plate 1 and the blade 2 is performed using a fixed TIG welding torch 3 while rotating around the center. Conventionally, this welding method has been applied to relatively large impellers with wide horizontal plate spacing L and blade spacing P. Therefore, the tip of the welding torch 3 also had a dimensional margin, and the straight length H of the gas flow path of the ceramic shield cup 4 could be set to an appropriate value. Since this straight portion H prevents diffusion and disturbance of the shielding gas, if its length is not sufficient, it will affect the shielding effect. Therefore, if the impeller is of a size that makes it impossible to set the linear length H to an appropriate value, that is, the horizontal plate spacing L and the blade spacing P are narrow enough to allow the torch body 3 to be inserted. If there is a need to weld such impellers, it is not possible to do so with a conventional TIG welding torch.

This invention can be inserted even in narrow places because it is necessary to weld small impellers where the torch insertion interval cannot be set to an appropriate value for the linear length H of the shield cup mentioned above. Another object of the present invention is to provide a TIG welding torch for use in narrow spaces, which can shield the welded area well.

The structure of the present invention to achieve such an object is to fix a torch head to the tip of a rod-shaped torch body in which a shielding gas passage and a cooling water passage are formed, facing in the same direction as the torch body; A shield gas flow path that connects to the shield gas flow path of the torch body and has an opening in the radial direction is drilled, and the electrode is fixed in the radial direction, and a shield gas outlet that surrounds the electrode is further drilled in the peripheral surface. The welding torch is characterized in that it comprises a welding torch with a shield cup placed over the torch head, and an auxiliary shield case that covers the welding torch and injects shielding gas into at least the electrode and its vicinity.

The configuration of the present invention will be described in detail below based on an embodiment shown in the drawings. Note that this embodiment is configured as a TIG welding torch used in the impeller welding apparatus shown in FIGS. 1 and 2.

A rod-shaped torch head 7 is attached to the tip of the torch body 3.
are fixed coaxially. The base portion of the torch head 7 is fitted into a torch outer cylinder 13 constituting the torch body 3, while the copper tube 14 is fitted into a recessed portion of the torch head 7, and the fillet portions of each are brazed and welded. In addition, this torch head 7 has
A small hole 17 communicating with the steel pipe 14 is bored. The small hole 17 forms part of the flow path for the shielding gas flowing inside the copper tube 14, and an opening is provided at a position opposite to the tungsten electrode 5, which is fixed to the torch head 7 by the screw 15. C is perforated. Furthermore, the torch head 7 is covered with a shield cup 6 made of ceramic. Therefore, the shielding gas ejected into the shielding cup 6 from the opening c through the copper tube 14 and the small hole 17 flows along the inner peripheral surface of the shielding cup so as to surround the torch head 7, and then surrounds the electrode. The shielding gas flows out from the shielding gas outlet b as a laminar flow.

The shield cup 6 is a cylindrical body having the same diameter as the torch body 3, and is screwed into a male thread cut into the torch head 7 and then fixed with a lock nut 10. The electrode 5, which is mounted so as to protrude radially from the shield cup 6, is attached after the shield cup 6 is attached to the torch head 7. The electrode 5 is inserted into the electrode mounting hole of the torch head 7 from the shield gas outlet b on the circumferential surface of the shield cup 6, and is pressed and fixed to the torch head 7 by a fixing screw 15 screwed into the tool insertion hole on the bottom of the shield cup 6. Ru. Fixing screw 15
After completely tightening, the plug 11 is screwed into the tool insertion hole on the bottom of the shield cup to close it.

Since it is difficult to obtain a sufficient shielding effect with only the shielding gas flowing out from the shielding gas outlet b, auxiliary shielding cases 8 to 8' are also used. The auxiliary shield cases 8, 8' are made by attaching a wire mesh 9 to the opening of the main body having a U-shaped cross section, and the wire mesh 9 rectifies the shielding gas supplied from the hose 16 into the cases 8, 8'. and then flow out as a laminar flow. The auxiliary shield cases 8, 8' are fixed, for example, to the base material, that is, the horizontal plate 1 of the impeller W, as shown in FIG. 3, or directly to the torch body 3, as shown in FIG. 6. When fixed to the base material W, the auxiliary shield case 8 is formed to have the same curvature as the blade 2 and slightly longer than the overall length of the blade, and is provided so that the entire welded portion is covered by the shielding gas flow. On the other hand, when attached to the main body 3, the auxiliary shield case 8' only needs to have an appropriate length in the welding direction around the electrode 5, and does not need to extend over the entire blade area. These auxiliary shield cases 8 and 8'
The shielding gas flowing out from the welding torch shields the entire tip of the welding torch from the atmosphere. It should be noted that one or several wire meshes 9 with fine mesh are used in order to provide an appropriate laminar flow of the shielding gas.

In this way, according to the present invention, the electrode and the welding area in the vicinity that require the most shielding gas are supplied with the shielding gas flow flowing out from the shielding gas outlet b of the welding torch and the auxiliary shielding cases 8 to 8'. As a result, a double shielding atmosphere is formed, so that a sufficient shielding effect can be ensured. Therefore, even in a narrow space where the straight portion H of the shield gas flow path described above cannot be provided with an appropriate length, a good shield can be obtained as long as there is a space in which the shield cup 6 and the auxiliary shield case 8 or 8' can be inserted. Creates an atmosphere to enable TIG welding. Thus, it becomes possible to assemble a small impeller by welding, and it is also possible to downsize an impeller that has been enlarged due to welding.

[Brief explanation of the drawing]

FIG. 1 is a plan view illustrating an outline of an impeller welding method using a conventional TIG welding torch, and FIG. 2 is an enlarged sectional view taken along the line A-A. 3rd to 6th
The figure shows the TIG welding torch for narrow spaces according to the present invention, Figure 3 is an enlarged cross-sectional view showing the welding state of the impeller corresponding to Figure 2, and Figure 4 is a longitudinal cross-sectional view showing the structure of the welding torch. , FIG. 5 is an enlarged sectional view showing the welding state of the impeller corresponding to FIG. 2 of another embodiment, and FIG. 6 is a plan view showing the external appearance of the welding torch. In the drawing, 1 and 2 are the horizontal plates and blades that constitute the base material W, 3 is the torch body, 5 is the electrode, 6 is the shield cup, 7 is the torch head, 8 and 8' are the auxiliary shield cases, and 17 is the shield gas flow. A small hole forming a part of the passage, b is a shielding gas outlet, and c is an opening.

Claims (1)

[Scope of utility model registration request] A torch head is fixed to the tip of a rod-shaped torch body that has a shielding gas flow path and a cooling water flow path formed therein, facing in the same direction as the torch body, and is connected to the shielding gas flow path of the torch body and has a diameter. a welding torch in which the torch head is covered with a shield cup that has a shield gas flow path having an opening in the direction, fixes the electrode in the radial direction, and has a shield gas outlet that surrounds the electrode in the peripheral surface; For use in narrow areas, the auxiliary shield case covers the welding torch and injects shielding gas into at least the electrode and its vicinity.
TIG welding torch.