JP2004314181A - Plasma arc cutting or welding machine, plasma torch, and method for attaching/detaching its component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate the exchange of consumables such as an electrode and a nozzle while suppressing complication of structure and cost increase in a plasma torch. <P>SOLUTION: An electrode 3, an insulation guide 5 and a nozzle 7 which are fitted to each other, are mounted on a retainer cap 13. The electrode 3, the insulation guide 5, the nozzle 7, and the retainer cap 13 are connected to each other through O-rings 93, 95, 97 with a connecting force to such an extent that they may be separable by hands. The electrode 3, the insulation guide 5 and the nozzle 7 can be attached to and detached from the torch body together by mounting and dismounting the retainer cap 13 on and from the torch body. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a plasma processing machine for plasma arc cutting or plasma arc welding, and more particularly to improvement of a structure for facilitating replacement work of consumables such as electrodes and nozzles in a plasma torch.

  In a plasma torch used for plasma arc machining, electrodes and nozzles are gradually consumed as the arc generation time elapses. Depending on the situation, these consumable parts may be exchanged several times during a day's machining operation.

  In order to replace the electrode and the nozzle, the electrode and the nozzle must be removed from the plasma torch. However, depending on the model, not only that but also other peripheral parts need to be removed together. Such peripheral components include, for example, an insulator guide interposed between the electrode and the nozzle, and one or more types of caps that are placed outside the nozzle.

  The plasma torch is fixed to a carriage provided above the work table, and is cut or welded to a workpiece on the work table while moving along a programmed movement path carried by the carriage. When exchanging the torch consumables, the torch is usually retracted to a place where the exchanging work can be easily performed, and the torch is disassembled to replace the consumables. However, since the work is exchanged on the work table, the work is never easy. In addition, since a plurality of small parts are removed from the torch or assembled in the replacement work, care must be taken not to drop these small parts from the hand. Also, when assembling parts, you must work carefully so that dust generated by cutting does not enter the torch.

  In order to facilitate the replacement of consumables that use such nerves, plasma torches called “cassette type torches”, “one-touch torches”, or “quick change torches” have been developed (Japanese Patent Laid-Open No. Sho). 62-50085, Japanese Patent Publication No. 3-27309). This cassette type torch can be divided into a head part including a torch tip, an electrode, a nozzle, a gas pipe and a cooling water pipe, and a base part including a power cable, a gas pipe and a cooling water pipe connected to the head part. It is like that. And connection and isolation | separation with a head part and a base part can be performed now easily. It is possible to easily replace consumables by preparing a plurality of heads with new consumables in advance and replacing the head connected to the base. With this cassette type torch, it is also possible to automate the replacement of consumables.

  In the cassette type plasma torch, the current path of two systems (electrodes and nozzles) of high current and high voltage, the gas piping of at least one system (plasma gas), and the cooling water piping going back and forth in the cooling water circuit, It is divided into a part on the part side and a part on the base part side, and their connection, electrical insulation and sealing are performed on the dividing surface of the head part and the base part.

  For this reason, the cassette type torch has a complicated torch structure and is much more expensive than the conventional ordinary torch described above, which is not a cassette type, although consumables can be easily replaced. In other words, it is necessary to connect and separate the head portion and the base portion easily and to provide sufficient electrical insulation and sealing so as not to cause poor electrical insulation and leakage of gas and water at the connection surface between them. Because the torch has to adopt a special structure that is not necessary, the price increases. For example, a normal torch is 100,000 yen, while a cassette type torch having the same processing capability as that is 400,000 yen or more. Therefore, cassette type torches are not so popular in reality.

  Accordingly, it is an object of the present invention to facilitate replacement of consumables while suppressing the complexity and cost of the plasma torch structure.

  The plasma torch according to the present invention includes a torch body having a cooling water pipe and a plasma gas pipe, and a detachable portion attached to the torch body in a detachable state.

  The detachable portion includes an electrode, a nozzle disposed so as to surround the electrode, an insulator interposed between the electrode and the nozzle, and a retainer cap that accommodates the electrode, the nozzle, and the insulator inside. The torch body further includes an electrode connection portion coupled to the electrode, a nozzle connection portion coupled to the nozzle, and a retainer cap connection portion coupled to the retainer cap.

  The connection structure between the electrode and the electrode connection part and the connection structure between the nozzle and the nozzle connection part are configured as follows. That is, the electrode and the nozzle are respectively coupled to the electrode connecting portion and the nozzle connecting portion of the main body of the torch as the retainer cap is coupled to the retainer cap connecting portion along a predetermined path (for example, along the torch axis). In addition, the electrode and the nozzle are detached from the electrode connecting portion and the nozzle connecting portion of the torch body as the retainer cap is removed from the retainer cap connecting portion and moved away along the predetermined path. Furthermore, the electrode, the insulator, the nozzle, and the retainer cap are coupled to each other, and the coupling force between them is the coupling force between the electrode and the electrode connection and the coupling force between the nozzle and the nozzle connection. Stronger than any of the. Therefore, by attaching or removing the retainer cap to or from the retainer cap connecting portion, all the parts of the detachable portion can be attached to or removed from the torch body together.

  In the plasma torch according to the present invention having the above-described configuration, the entire detachable portion can be gathered, that is, the electrode, the insulator, and the nozzle can be attached to the torch body together with the retainer cap and can be separated from the torch body. Therefore, when replacing consumables such as electrodes and nozzles, it is not necessary to remove and attach the electrodes and nozzles individually from the torch body, only to remove and attach the retainer cap from the torch body. Thus, the electrode and the nozzle can be detached from or attached to the torch body. Therefore, the consumable item replacement work is easy. It is also possible to configure so that consumables can be replaced fully or semi-automatically using an automatic changer.

  The plasma torch according to the present invention has a structure in which the electrode, the nozzle and the retainer cap are coupled to the torch body. This is decisively different from the structure of the conventional cassette type torch. That is, the conventional cassette type torch has an intermediate connection structure for performing electrical connection and piping connection between the head portion and the torch main body separately from the electrodes, nozzles and caps. In contrast, the plasma torch according to the present invention does not require such an intermediate connection structure.

  In a preferred embodiment, the electrode and nozzle are individually separable from the retainer cap. Therefore, it is possible to replace only the electrode and only the nozzle.

  In a preferred embodiment, the electrode, the nozzle, and the retainer cap are coupled to each other by a coupling structure using an elastic body. Therefore, by deforming the elastic body, the coupling can be released and the electrode and the nozzle can be easily separated from the retainer cap, so that the consumable replacement operation is further facilitated.

  In a preferred embodiment, the electrode and the electrode connection part each have a current-carrying surface that is in contact with each other to ensure electrical connection between the electrodes, and the current-carrying surfaces of the electrode and the electrode connection part are at least of the electrode and the electrode connection part. They are in contact with each other with a pressing force due to the deformation of the elastic deformation portion provided on one side. Therefore, even if the coupling structure between the electrode and the electrode connecting portion is easy to attach and detach, for example, by simply inserting the electrode into the electrode connection and fitting it, the energizing surface is pressed by the pressing force due to the deformation of the elastically deforming portion. Good electrical connection can be secured.

  Other features of the present invention will become apparent in the description of the embodiments.

  FIG. 1 shows a cross section along the central axis of a cutting plasma torch according to an embodiment of the present invention.

The plasma torch 1 is designed to remove a cap (retainer cap) 13 that constitutes the outer shell of the tip of the torch when consumables (mainly electrodes and nozzles) are replaced. When the retainer cap 13 is removed, consumable parts such as the electrode 3 and the nozzle 7 are detached from the torch body together with the retainer cap 13 in a coupled state. FIG. 2 shows a cross section of the torch main body when the retainer cap 13 is removed, and FIG. 3 shows a cross section of a set of the retainer cap 13 and the parts detached together with the retainer cap 13.

  First, an overall configuration of the cutting plasma torch 1 will be described mainly with reference to FIG. 1 and with reference to FIGS. 2 and 3 supplementarily.

  The plasma torch 1 includes a torch body 1A (part shown in FIG. 2) fixed to a carriage (not shown), and a detachable part 1B (part shown in FIG. 3) detachably attached to the torch body 1A. It is roughly divided into The detachable portion 1B is composed of an electrode 3, an insulating guide 5, a nozzle 7, an insulating ring 9, a shield cap 11, a retainer cap 13, and a rotating ring 39 in order from the torch axis toward the outside. The nozzle 7 is a consumable item and is replaced as needed. By removing the retainer cap 13 from the torch main body 1A, the entire detachable portion 1B is collectively removed from the torch main body 1A. Separating the electrode 3, the insulating guide 5, and the nozzle 7 from the detachable portion 1 </ b> B can be easily performed by simply pulling out these components from the retainer cap 13 by hand. The attachment of the detachable part 1B to the torch body 1A can be easily performed only by attaching the retainer cap 13 to the torch body 1A, and the work of individually attaching the individual parts of the detachable part 1B to the torch body 1A is unnecessary.

  A water guide pipe 15 having a circular cross section for introducing cooling water into the electrode 3 is disposed at the central axis position of the torch 1 (torch body 1A). A cylindrical inner sleeve 17 is fitted on the outer periphery of the proximal end portion of the water guide pipe 15 in a positional relationship coaxial thereto. The proximal end portion of the cylindrical electrode 3 is fitted inside the distal end portion of the inner sleeve 17. The electrode 3 has a closed tip portion 3A, and a heat-resistant insert 4 made of hafnium or the like is attached to a portion of the tip portion 3A that becomes an arc generation point. The back surface of the heat-resistant insert 4 is exposed in a space in which the cooling water inside the electrode 3 flows.

  The water guide pipe 15 protrudes forward from the front end surface of the inner sleeve 17 and enters deep inside the electrode 3, and the water outlet 15 </ b> A of the water guide pipe 15 reaches a position just behind the heat-resistant insert 4 at the front end portion 3 </ b> A of the electrode 3. Yes. Paying attention to the diameter of the water conduit 15, the large large diameter portion 15B contained in the inner sleeve 17 and the small small diameter portion 15D extending from the water outlet 15A at the tip contained in the electrode 3 to a predetermined length. The tapered portion 15C connects the large diameter portion 15B and the small diameter portion 15D. In accordance with such a change in the thickness of the water conduit 15, the thickness of the electrode 3 changes in the same manner. That is, the electrode 3 is thick at the base end side portion 3B where the large diameter conduit portion 15B is inserted, the inner diameter is tapered at the portion 3C where the tapered conduit portion 15C is inserted, and the small conduit portion 15D. It is thin at the tip side portion 3D containing the. Then, the nozzle 7 is placed outside the thin tip side portion 3D of the electrode 3. Therefore, the thin tip side portion 3D of the electrode 3 contributes to reducing the overall thickness of the torch 1. For this reason, it is preferable that the outer diameter of the small diameter portion 15D of the water conduit 15 is as thin as possible. On the other hand, the inner diameter of the water conduit 15 (that is, the cross-sectional area of the cooling water passage 19) is between the small diameter portion 15D and the large diameter portion 15B. It is desirable that there is no big difference. In order to satisfy this requirement, the thickness of the wall of the water conduit 15 is made thinner in the small diameter portion 15D than in the large diameter portion 15B.

  The water conduit 15 has a cooling water passage 19 therein. A cooling water passage 21 is formed between the inner peripheral surface of the electrode 3 and the outer peripheral surface of the water conduit 15. A cooling water passage 23 is formed between the inner peripheral surface of the inner sleeve 17 and the outer peripheral surface of the water conduit 15. A cooling water channel 25 is formed through the peripheral wall of the inner sleeve 17. These cooling water channels 19, 21, 23, 25 are communicated in this order. The cooling water channels 19 and 21 in the electrode 3 are designed to have substantially the same cross-sectional area, so that the resistance (pressure loss) of the reciprocating cooling water channels 19 and 21 to which a limited space inside the electrode is distributed is Be minimized. The downstream cooling water channels 23 and 25 are designed to have a maximum cross-sectional area as far as structurally possible in order to minimize the pressure loss.

  A ring magnet 27 for rotating and moving an arc generation point in the heat-resistant insert 4 of the electrode 3 is fitted on the outer periphery of the tip portion of the inner sleeve 17. A cylindrical outer sleeve 29 is fitted on the outer periphery of the proximal end portion of the inner sleeve 17. A short cylindrical nozzle pedestal 31 is fixed to the distal end portion of the outer sleeve 29, and a substantially conical cylindrical nozzle 7 tapered toward the distal end is attached to the distal end portion of the nozzle pedestal 31. The nozzle 7 is placed coaxially with the electrode 3 and covers the outer side of the thin portion 3D of the electrode 3 described above, and the plasma arc is narrowed down to the center axis position of the nozzle tip which is the front surface of the heat-resistant insert 4. It has a nozzle orifice 7A for jetting forward.

  A cylindrical insulating guide 5 for electrically insulating the nozzle 7 and the electrode 3 is fitted. A plurality of grooves 33 are formed on the outer periphery of the insulating guide 5 in a direction parallel to the axis, and the plurality of grooves 33 function as a plasma gas passage. Plasma gas flows into these plasma gas passages 33 from a plasma gas supply passage (not shown) (which passes through the inside of the outer sleeve 29 and the nozzle base 31). A plasma gas passage 35 communicating with the nozzle orifice 7A is formed between the nozzle 7 and the tip 3A of the electrode 3. Further, the insulating guide 5 is formed of a plurality of plasma gases that are formed at regular intervals in the circumferential direction so as to communicate with the plasma gas passage 33 and the plasma gas passage 35 at a slight angle in the circumferential direction with respect to the radial direction. It has a swirler hole 5A. The plasma gas enters the plasma gas swirler hole 5 </ b> A from the plasma gas passage 33, and is swung out from the plasma gas swirler hole 5 </ b> A to the plasma gas passage 35. This plasma gas swirl flows through the plasma gas passage 35 and is converted into plasma by the energy of the arc in front of the heat-resistant insert 4 and is ejected from the nozzle orifice 7A as a plasma swirl.

  The tip of the nozzle 7 is covered with a short cylindrical shield cap 11 for protecting the nozzle 7 from a workpiece (not shown) or a molten metal blown from the workpiece. Between the nozzle 7 and the shield cap 11, the insulating ring 9 which electrically insulates both is inserted. A cylindrical retainer cap 13 that is tapered toward the tip is covered outside the structure.

  A cylindrical rotating ring 39 is fitted to the outside of the base end portion of the retainer cap 13. An annular claw 39B formed by bending inwardly at the distal end portion of the rotating ring 39 is engaged with a flange 13A formed at the proximal end portion of the retainer cap 13, whereby the rotating ring 39 causes the retainer cap 13 to be engaged. Raised. A cylindrical fixing ring 37 is fitted on the outer periphery of the base end portion of the outer sleeve 29. A female screw 39 </ b> A formed on the inner periphery of the rotating ring 39 is coupled to a male screw 37 </ b> A formed on the outer periphery of the fixing ring 37. By rotating the rotating ring 39 around the central axis of the torch, the screwing between the rotating ring 19 and the fixing ring 37 can be tightened or loosened. In a state where the rotating ring 19 is fastened to the fixing ring 37 most, the retainer cap 13 is attracted and fixed to the torch body 1B by the rotating ring 19.

  An annular claw 13B at the distal end portion of the retainer cap 13 is engaged with a flange 11A at the proximal end portion of the shield cap 11, so that the retainer cap 13 is connected to the nozzle protection cap 11, the insulating ring 9, and the nozzle 7. The set of the insulating guide 5 and the electrode 3 is attracted and fixed to the torch body. The retainer cap 13 has a function as an outer shell of the torch 1 in the tip side portion of the torch 1 in addition to the function of holding the internal components.

  The outer sleeve 29 runs in the radial direction, the cooling water passage 41 running in the radial direction, the cooling water passage 43 running in the direction parallel to the central axis of the torch, and the direction away from the cooling water passage 43 in the same direction parallel to the central axis of the torch. And another cooling water passage 47. A cooling water passage 45 that surrounds the outside of the nozzle 7 is formed between the outer peripheral surface of the nozzle 7, the inner peripheral surface of the retainer cap 13, and the proximal end surface of the shield cap 11. The cooling water passage 25 in the inner sleeve 17, the cooling water passages 41 and 43 in the outer sleeve 29, the cooling water passage 45 surrounding the nozzle 3, and another cooling water passage 47 in the outer sleeve 29 are provided in this manner. Communicate in order. The cooling water passage 47 also communicates with a cooling water discharge passage (not shown). All of the cooling water channels 41, 43, and 47 in the outer sleeve 29 are designed to have a maximum cross-sectional area as far as structurally possible in order to minimize the pressure loss due to the cooling water.

  As shown by the arrows, the cooling water first passes through the cooling water passage 19 in the water conduit 15 and exits from the water outlet 15A, hits the back surface of the hottest heat-resistant insert 4 at the tip 3A of the electrode 3, and the heat-resistant insert 4 Cool down. The heat-resistant insert 4 is effectively cooled by being directly exposed to the cooling water. Moreover, the front surface of the heat-resistant insert 4 is flat, but the back surface has a curved shape that is high at the center and low at the periphery as shown in the figure, thereby ensuring a wide area of the back surface, that is, a contact area with cooling water. Has been. In addition, this curved shape also has a function of smoothly folding the cooling water that has exited from the water outlet 15 </ b> A and guiding it to the cooling water passage 21. One or more slits 15E are provided around the water outlet 15A of the water conduit 15. A portion of the cooling water flowing through the cooling water passage 19 passes through the slit 15E and enters the cooling water passage 21 without touching the heat-resistant insert 4 and effectively contributes to cooling the nozzle 7. The cooling water guided to the cooling water passage 21 cools the electrode 3 while flowing through the cooling water passage 21 along the inner peripheral surface of the electrode 3, and then sequentially passes through the cooling water passages 23, 25, 41, 53. Pass through and enter the cooling water passage 45 surrounding the nozzle 7. The cooling water that has entered the cooling water channel 45 cools the nozzle 7 while flowing through the cooling water channel 45 and also cools the shield cap 11 and the retainer cap 13. In this way, all of the parts that require cooling around the nozzle, such as the nozzle 7, the shield cap 11, and the retainer cap 13, are exposed in the same cooling water passage 45 and are simultaneously cooled by the cooling water flowing therethrough. This contributes to minimizing the size of the torch by minimizing the number of required cooling water channels (especially by eliminating the need to provide a cooling water channel in the retainer cap or the like). The cooling water that has passed through the cooling water channel 45 is discharged out of the torch 1 through the cooling water channel 47.

  An annular secondary gas passage 51 is formed between the base end portion of the retainer cap 13 and the outer sleeve 29. A plurality of grooves 13C running from the proximal end portion of the retainer cap 13 to the distal end portion are formed on the outer peripheral surface of the retainer cap 13 at regular intervals in the circumferential direction, and the outer opening of each groove 13C is elongated. The space in the groove 13 </ b> C completely covered with the lid 13 </ b> D is a secondary gas passage 53. Each of the multiple secondary gas passages 53 in the retainer cap 13 has a retainer cap 13 and an outer sleeve at its proximal end through a large number of secondary gas introduction holes 13E formed in the proximal end portion of the retainer cap 13. It communicates with the annular secondary gas passage 51 between 29. In addition, each of the multiple secondary gas passages 51 in the retainer cap 13 is provided at the tip thereof with the retainer cap 13 and the nozzle protection through a number of secondary gas ejection holes 13F formed at the tip of the retainer cap 13. It communicates with an annular secondary gas passage 55 formed between the cap 11 and the cap 11. The annular secondary gas passage 55 communicates with a plurality of secondary gas swirler holes 11C formed in the nozzle protection cap 11 at regular intervals in the circumferential direction and inclined at a slight angle in the circumferential direction with respect to the radial direction. is doing. The secondary gas swirler holes 11 </ b> C communicate with a secondary gas passage 57 formed between the shield cap 11 and the tip of the nozzle 7, and the secondary gas passage 57 is formed at the tip of the shield cap 11. Further, the secondary gas ejection port 11B having a diameter larger than the nozzle orifice 7A communicates.

  The secondary gas flows into a secondary gas passage 51 from a secondary gas supply passage (not shown) formed in the outer sleeve 29, and then passes through a plurality of secondary gas passages 53 in the retainer cap 13. , Reaches the secondary gas passage 55 between the tip of the retainer cap 13 and the shield cap 11, and further passes through the plurality of secondary gas swirler holes 11C penetrating the nozzle protection cap 11 from the outside to the inside to form a swirling flow. It ejects to the secondary gas passage 57 inside the shield cap 11. This secondary gas swirl flows through the secondary gas passage 57 and is ejected from the secondary gas ejection port 11B to the periphery of the plasma arc ejected from the nozzle orifice 7A. The swirl direction of the secondary gas swirl flow created by the secondary gas swirler hole 11C and the swirl direction of the plasma arc (plasma gas) swirl flow created by the plasma gas swirler hole 5A are the same.

  A tertiary gas passage 61 for supplying a tertiary gas is formed in the fixing ring 37. The tertiary gas passage 61 communicates with an annular tertiary gas passage 63 formed between the fixing ring 37 and the retainer cap 13. In addition to the secondary gas passage 53 described above, the retainer cap 13 also has a large number of tertiary gas passages 65 that are configured by grooves 13G and a lid 13H and run from the base end to the tip. The tertiary gas passages 6 and the secondary gas passages 53 are alternately arranged. The plurality of tertiary gas passages 65 are formed at the base end thereof through an annular 3 between the fixing ring 37 and the retainer cap 13 through a number of secondary gas introduction holes 13I formed in the base end portion of the retainer cap 13. It communicates with the next gas passage 63. Further, the numerous tertiary gas passages 65 communicate with the numerous tertiary gas swirler holes 13J formed in the distal end portion of the retainer cap 13 at the distal ends thereof. These tertiary gas swirler holes 13J are also inclined at a certain angle in the circumferential direction and at a slight angle in the circumferential direction with respect to the radial direction so that the tertiary gas swirls in the same direction as the secondary gas. An annular tertiary gas passage 67 surrounding the tip of the cap 11 is opened.

  The tertiary gas flows from the tertiary gas passage 61 in the fixing ring 37 into the tertiary gas passage 63 between the fixing ring 37 and the retainer cap 13, and subsequently, a number of tertiary gas passages in the retainer cap 13. Through 65, it reaches the tertiary gas swirler hole 13J at the tip of the retainer cap 13, and the swirl flows from the tertiary gas swirler hole 13J to the periphery of the secondary gas swirl.

  As described above, since the secondary gas passage 53 and the tertiary gas passage 65 are formed inside the retainer cap 13, a passage for the secondary gas and the tertiary gas is provided between the retainer cap 13 and the nozzle 7. There is no need. For this reason, the entire space between the nozzle 7 and the retainer cap 13 can be used as the cooling water channel 45. As a result, as described above, the nozzle 7 and the retainer cap are used in the same cooling water channel 45. 13 and the shield cap 11 can be cooled at the same time, and there is an advantage that an unnecessary cooling water channel is unnecessary and the size can be reduced.

  The above is the overall configuration of the plasma torch 1. Next, the torch body 1A and the detachable part 1B will be described with reference to FIGS.

  As shown in FIG. 2, the torch main body 1 </ b> A includes a water conduit 17, an inner sleeve 17, an outer sleeve 29, a nozzle pedestal 31, a fixing ring 37, and various components (not shown) that are present on the proximal side of the torch. Has been. As shown in FIG. 3, the detachable portion 1 </ b> B includes various parts that can be attached to and detached from the torch, such as the electrode 3, the insulating guide 5, the nozzle 7, the shield cap 11, and the retainer cap 13.

  What should be noted here is that the torch body 1A and the detachable portion 1B are decisively different from the configurations of the torch body and head portion of the conventional cassette type torch in the following points.

  That is, in the conventional cassette type torch, in addition to the electrical connection part, the cooling water pipe and the gas pipe which the electrode, nozzle and cap included in the head part originally have, the torch body and the head part are connected. Additional intermediate electrical connections, cooling water pipe connections and gas pipe connections, which complicate the structure of the cassette torch. On the other hand, in the plasma torch 1 according to the principle of the present invention, in addition to the electrical connection part, the cooling water pipe, and the gas pipe that the electrode 3, the nozzle 7 and the shield cap 11 included in the detachable part 1B originally have. Does not have an additional intermediate electrical connection or pipe connection for connecting the torch body 1A and the detachable part 1B.

  For example, the torch body 1A shown in FIG. 2 has removable parts such as the electrode 3, the insulating guide 5, the nozzle 7, the shield cap 11, and the retainer cap 13 included in the detachable portion 1B from the completed torch shown in FIG. It has the same configuration as simply removed individually. That is, the torch main body 1A only has a portion for directly connecting to each of the detachable parts such as the electrode 3, the nozzle 7 and the retainer cap 13, and the detachable part other than the direct connecting part to the detachable parts. There are no additional intermediate electrical or pipe connections to 1B. Further, the detachable portion 1B shown in FIG. 3 is substantially composed only of detachable parts such as the electrode 3, the insulating guide 5, the nozzle 7, the shield cap 11, and the retainer cap 13. In other words, the detachable portion 1B includes only removable parts that are directly coupled to the torch body 1A such as the electrode 3, the nozzle 7, and the retainer cap 13 in relation to the torch body 1A. There is no typical electrical connection or pipe connection. Further, the electrode 3, the insulating guide 5, the nozzle 7, the shield cap 11, and the retainer cap 13 in the detachable portion 1B themselves constitute a cooling water passage and a gas passage, but additional components other than these components are used. The detachable part 1B does not have a cooling water pipe or a gas pipe.

  For this reason, the plasma torch 1 is much simpler than the conventional cassette type torch in terms of the complexity of the configuration, and is therefore less expensive. In addition, as will be described below, the plasma torch 1 is not inferior to the conventional cassette type torch in terms of easy replacement of consumables such as the electrodes 3 and the nozzles 7.

  As shown in FIG. 3, in the detachable portion 1 </ b> B, the electrode 3, the insulating guide 5, the nozzle 7, and the shield cap 11 are contained inside the retainer cap 13. The electrode 3, the insulating guide 5, and the nozzle 7 are fitted to each other, and the three can be separated separately by manually pulling one away from the other along the axial direction. The coupling force between the electrode 3 and the insulating guide 5 is mainly obtained by the frictional force of an elastic O-ring 93 such as rubber interposed between them, and the coupling between the insulating guide 5 and the nozzle 75. The force is obtained mainly by the frictional force of the elastic O-ring 95 interposed between the two. Further, the nozzle 7 and the shield cap 11 are fixed via an insulating ring 9, and the user cannot separate them (of course, they may be separable by fitting).

  The shield cap 11 is fitted into the distal end portion of the retainer cap 13 in a detachable state. An annular bank 13K having an inner diameter slightly larger than the outer shape of the flange 11A at the base end of the shield cap 11 is formed on the inner surface of the distal end portion of the retainer cap 13, and the shield cap 11 is formed inside the annular bank 13K. The flange 11A is inserted. At the bottom of the annular bank 13K, the annular claw 13B described above protrudes inward, and the annular claw 13B engages with the flange 11A of the shield cap 11 to hold the shield cap 11. Further, an O-ring 97 made of an elastic material is fitted into a portion of the inner surface of the annular bank 13K above the flange 11A. The inner diameter of the O-ring 97 is slightly smaller than the outer shape of the flange 11A of the shield cap 11, and protrudes further inward from the inner surface of the annular bank 13K. Therefore, the shield cap 11 fitted into the distal end portion of the retainer cap 13 is prevented from coming out of the retainer cap 13 by the O-ring 97. The shield cap 11 is separated from the retainer cap 13 when the flange 11 </ b> A is pulled away from the retainer cap 13 with a force necessary to crush the O-ring 97 and pass the position of the O-ring 97.

  When attaching the detachable part 1B having the above configuration to the torch main body 1A, the retainer cap 13 is attached to the torch main body 1A in a state in which the water conduit 15 of the torch main body 1A is aligned so as to be inserted into the electrode 3. The rotation ring 39 at the base end portion of the retainer cap 13 may be fitted and screwed onto the fixing ring 37 of the torch body 1A. In short, all the parts constituting the detachable part 1B are combined and coupled to the torch body 1A by simply attaching the retainer cap 13 to the torch body 1A. Further, when the detachable part 1B attached to the torch body 1A is removed from the torch body 1A for exchanging consumables, the fixing ring 37 and the rotating ring 39 are unscrewed, and the retainer cap 13 is simply torched. What is necessary is just to pull away from the main body 1A.

  In a state where the detachable portion 1B is mounted on the torch body 1A, the electrode 3 has a plurality of elastic tongues 77 formed on the base end portion 3B thereof, as will be described in detail later, and the inner sleeve 17 of the torch body 1A. The inner sleeve 17 is connected to the inner sleeve 17 by frictional resistance at the contact surface. The nozzle 17 is in contact with the distal end surface 31A of the nozzle base 31 of the torch body 1A at the nozzle base end surface 7B perpendicular to the torch axis. Therefore, when the detachable portion 1B is detached from the torch body 1A, the force that prevents the detachable portion 1B from being separated from the torch body 1A is only the coupling force due to the friction between the electrode 3 and the inner sleeve 17. Compared to the coupling force between the electrode 3 and the inner sleeve 17, the coupling force between the components constituting the detachable portion 1B is designed to be larger. Therefore, when the operation of removing the retainer cap 13 from the torch body 1A is performed, the electrode 3, the insulating guide 5, the nozzle 7, the shield cap 11 and the like in the retainer cap 13 are joined to the retainer cap 13 together with the torch body 1A. That is, the detachable part 1B is collectively removed from the torch body 1A.

  The operation of disassembling the detachable part 1B into individual parts is extremely simple. Since all the parts are joined with a simple fit, they can be disassembled by simply pulling them apart in the axial direction. The disassembly procedure is user-friendly, but a typical procedure is as follows. First, as shown in FIG. 3, the retainer cap 13 having the electrode 3, the nozzle 7, and the like inside is firmly grasped from the outside by hand, and the shield cap 11 exposed at the tip of the retainer cap 13 is thumbed up. To push upward in FIG. With this pressing force, the flange 11 </ b> A of the shield cap 11 gets over the O-ring 97, and the shield cap 11 is detached from the retainer cap 13. Therefore, a combined body (hereinafter referred to as a three-part set) of the electrode 3, the insulating guide 5, and the nozzle 7 as shown in FIG. 4 is taken out from the retainer cap 13. Since the shield cap 11 is fixed to the tip of the nozzle 7, it is regarded as a part of the nozzle 7 in the following description. Next, when the electrode 3, the insulating guide 5 and the nozzle 7 are pulled apart by hand along the axial direction, they are separated into individual parts 3, 5 and 7 as shown in FIG. 5. The assembly of the detachable unit 1B may be performed in the reverse order of the above. That is, the detachable portion 1B is assembled by simply pressing the electrode 3, the insulating guide 5, the nozzle 7 and the retainer cap 13 together.

  The above-described disassembly and assembly operation of the detachable part 1B is simpler than that of the head part of the conventional cassette type torch. Since the head part of the conventional cassette type torch includes not only the parts essential for the torch such as electrodes, nozzles, and caps, but also additional intermediate parts for electrical connection and piping connection to the torch main body, Disassembly and assembly are not as simple as the detachable part 1B.

  The O-rings 91, 93, 95, and 97 for connecting the electrode 3, the insulating guide 5, the nozzle 7 and the retainer cap 13 can be replaced with other parts having similar functions. For example, instead of the O-ring 97 of the retainer cap 13, a leaf spring or rubber piece slightly protruding inward may be used.

  FIG. 6 shows an example of the procedure for exchanging consumables of the plasma torch 1 according to the present invention described above.

  First, the plasma torch 1 is moved to a predetermined exchange position in the plasma processing machine (S1). Next, the rotating ring 39 of the plasma torch 1 is turned and loosened, and the retainer cap 13 is removed from the torch body 1A (S2). As described above, all the parts of the detachable portion 1 </ b> B are detached together with the retainer cap 13. Next, the three-component set in which the electrode 3, the insulating guide 5 and the nozzle 7 contained in the retainer cap 13 are coupled is removed from the retainer cap 13 (S3). Next, the three component set is separated into the electrode 3, the insulation guide 5, and the nozzle 7 (S4).

  Next, of the separated electrode 3, insulation guide 5, and nozzle 7, the parts that need to be replaced are replaced with new ones (S5). Next, the electrode 3, the insulation guide 5, and the nozzle 7 are combined to form a three-part set (S6). Next, the three-part set is fitted into the retainer cap 13 (S7). Thus, the detachable part 1B after the consumable replacement is prepared. Next, the retainer cap 13 of the detachable portion 1B is put on the tip portion of the torch body 1A, and the rotating ring 13 is turned and completely tightened (S8). This completes the replacement work. The torch 1 is returned to the work position and the machining work is started (S9).

  All of the above replacement operations can be performed manually, but can also be performed fully automatically or semi-automatically using an automatic consumable replacement device. FIG. 7 shows the overall configuration of a plasma processing machine equipped with an automatic consumables exchange device.

  A steel plate as the workpiece 101 is placed horizontally on the work stage 103. A Y carriage 105 is installed with respect to the work stage 103 so as to be horizontally movable in the Y direction. A guide rail 107 protrudes from the Y carriage 105 in the X direction, and the X carriage 109 can move in the X direction horizontally on the guide rail 107. A Z carriage 111 that moves in the Z (vertical) direction is attached to the X carriage 109, and the plasma torch 1 having the structure shown in FIG. 1 is fixed to the Z carriage 111 facing downward. While the workpiece 101 is being processed, the plasma torch 1 has a constant standoff (distance from the workpiece upper surface to the tip of the torch) with respect to the workpiece 101 by the XYZ moving system including the carriages 105, 109, and 111. In the X and Y directions along the processing line that matches the product shape.

  A consumable automatic changer 113 is installed at a predetermined position on the side of the work stage 103. The XYZ moving system described above can move the plasma torch 1 not only on the work table 103 but also to a position above the consumable automatic changer 113. A plurality of detachable part holders 115, 115,... Are provided on the upper part of the consumable automatic changer 113, and one detachable part 1 B is set in each detachable part holder 115 with the front end facing downward. can do. Each detachable part holder 115 removes the detachable part 1B (that is, the retainer cap 13) from the plasma torch 1 or attach the detachable part 1B (that is, the retainer cap 13) to the torch body 1A by the method described above. It has a function to do. At least one detachable unit holder 115 is pre-set with a detachable unit 1B in which a consumable item is new, and at least one other detachable unit holder 115 is empty.

  When exchanging the consumables of the plasma torch 1, first, the XYZ moving system moves the plasma torch 1 to the position immediately above the empty detachable holder 115 of the consumable automatic changer 113, and then lowers the plasma torch 1 Then, the detachable part 1B is set in the empty detachable part holder 115. Next, the detachable part holder 115 is operated to loosen the rotating ring 39 of the plasma torch 1 and remove only the detachable part 1B.

  Next, the XYZ moving system pulls up the plasma torch main body 1A from which the detachable part 1B is detached, and moves it up to the detachable part holder 115 where the detachable part 1B of another new consumable is set, and Then, the torch body 1A is lowered and fitted into the detachable part 1B of the new consumable item. Next, the detachable part holder 115 is actuated to rotate the rotating ring 29 of the detachable part 1B fitted in the torch body 1A to fix the detachable part 1B to the torch body 1A. This completes the exchange. Thereafter, the XYZ moving system pulls up the exchanged plasma torch 1, returns it to the work position on the work table 103, and the machining work is resumed.

  The automatic exchanging work by the consumable automatic exchanging apparatus 113 described above is the step of skipping steps S3 to S7 from step S2 to step S8 in the exchanging procedure shown in FIG. Steps S3 to S7 (removal and disassembly of the old detachable part 1B from the detachable part holder 115 and assembly of the new detachable part 1B and setting to the detachable part holder 115) may be performed manually or may be automated. Good.

  FIG. 8 simply shows the configuration of the detachable part holder 115 of the consumable supply automatic changer 113 (parts inside the torch 1 are not shown).

  The detachable part holder 115 includes a cap holder 117 that holds the retainer cap 13 of the detachable part 1B in a stationary state, and a rotating ring driver 119 that grips and operates the rotating ring 39 of the detachable part 1B. The cap holder 117 is a cylindrical part that is provided in a stationary state in the consumable automatic changer 113, and is attached to the outer surface of the tip of the retainer cap 13 so that the retainer cap 13 does not move during the replacement operation. To do. The rotating ring driver 119 is a cylindrical part arranged on the outer periphery of the cap holder 117 so as to be coaxial with the cap holder 117. The rotating ring driver 119 holds the rotating ring 39 and rotates the rotating ring 39 clockwise around a torch axis (shown by a one-dot chain line). And it can be raised and lowered in the torch axis direction while rotating counterclockwise. The drive mechanism of the rotating ring driver 119 is not shown.

  FIG. 8A shows a state immediately before fixing the detachable part 1B to the torch body 1A. At this time, the rotating ring driver 119 holds the rotating ring 39 of the detachable portion 1B at a low position that does not protrude upward from the retainer cap 13. In this state, the torch body 1A is completely fitted into the detachable part 1B without colliding with the rotating ring 39. Subsequently, the rotating ring driver 119 raises the rotating ring 39 at a rotation speed / rising speed ratio that matches the pitch of the screws 39A of the rotating ring 39 while rotating the rotating ring 39 clockwise. Thereby, the rotating ring 39 is screwed into the fixing ring 37 of the torch main body 1A, and this screwing is tightened. As shown in FIG. 8B, when the screwing of the rotating ring 39 and the fixed ring 37 is completely tightened, the rotating ring driver 119 stops. This completes the mounting of the detachable portion 1B to the torch body 1A.

  When the detachable part 1B is removed from the torch body 1A, from the state shown in FIG. 8B, the rotating ring driver 119 rotates the rotating ring 39 counterclockwise while rotating the rotating ring 39 according to the pitch of the screws 39A. / It descends at the descending speed ratio. By this. The screwing between the rotating ring 39 and the fixing ring 37 is loosened. As shown in FIG. 8A, when the fixed ring 37 is completely removed from the rotating ring 39, the rotating ring driver 119 stops. Thereafter, the torch body 1Aga is raised, whereby the detachable part 1B is separated from the torch body 1A.

  As described above, the replacement of the consumables of the plasma torch 1 according to the present invention is easy and suitable for automatic replacement.

  The plasma torch 1 according to the present invention has excellent features in several aspects other than the replacement of consumables. Among these, the features regarding two viewpoints, that is, the first feature relating to the electrical connection of the electrode 3 and the second feature relating to the positional alignment of the electrode 3 and the nozzle 7 will be described below. First, the first feature will be described.

  FIG. 9 shows a cross section of the electrode 3 of the plasma torch 1 described above. FIG. 10 shows a cross section of the inner sleeve 17 and the water conduit 15 of the torch main body 1A. FIG. 11 shows a state in which the electrode 3 is attached to the inner sleeve 17.

  As shown in FIG. 9, the electrode 3 is made of, for example, copper, and a skirt portion 73 surrounding the base end opening 71 has a predetermined length and a predetermined width at regular intervals from the base end surface in a direction parallel to the electrode axis. A plurality of (for example, two, three, or four) slits 75 are engraved. By these slits 75, the skirt portion 73 is divided into a plurality of (for example, two, three, or four) tongues (rectangular plates curved in an arc) 77, and each tongue 77 has a diameter with elasticity. A small distance can be deflected inward in the direction. The skirt portion 73 has a large-diameter portion 79 that is slightly larger than the other portions in both the inner diameter and the outer diameter. The outer diameter of the large-diameter portion 79 is that the tongue 77 is elastically bent inward. To reduce slightly. The outer peripheral surface 79A of the large-diameter portion 79 is a surface parallel to the electrode axis, and functions as an energization surface in close contact with the inner surface of the inner sleeve 17 as will be described later. A stainless steel spring ring 81 is fitted inside the large diameter portion 79 so as to be in close contact with the inner peripheral surface 79B of the large diameter portion 79. Although not shown in the drawing, this spring ring 81 is not a complete ring, but is a C-shaped one cut by a slit at one location, and is elastic from the inside to a copper tongue 77 which is originally not rich in elasticity. A force is added to prevent plastic deformation when the tongue 77 is bent inward, and to strengthen the contact pressure on the inner surface of the inner sleeve 17 of the energizing surface 79A. The outer peripheral edge of the base end of the large diameter portion 79 is an obliquely chamfered surface 79C, and this chamfered surface 79C facilitates insertion of the electrode 3 into the inner sleeve 17.

  A flange 83 is formed on the outer periphery of the electrode 3 at a position slightly shifted from the skirt portion 73 toward the tip side by a distance. The flange 83 has a small-diameter portion 83A having a relatively small outer diameter at its proximal end portion and a large-diameter portion 83B having a relatively large outer diameter at its distal-end side portion. On the outer periphery of the electrode 3, the above-described elastic O-ring 91 is fitted at a position between the skirt portion 73 and the flange 63. The O-ring 91 is in contact with an end face on the proximal end side of the flange 83 (a face perpendicular to the electrode axis).

  As shown in FIG. 10, the inner sleeve 17 serves to hold the electrode 3 and supply current to the electrode 3.

  Between the outer peripheral surface of the water guide pipe 15 and the inner peripheral surface of the inner sleeve 17, a space 121 is formed for fitting a portion closer to the base end side than the flange 83 of the electrode 3. The inner peripheral surface 123 of the inner sleeve 17 has a tapered surface 123 </ b> A whose inner diameter tapers from the distal end toward the proximal end at the distal end thereof. The diameter of the most open portion of the tapered surface 123 </ b> A, that is, the inner diameter of the tip of the inner sleeve 17 is slightly larger than the outer diameter of the small diameter portion 83 </ b> A of the flange 83 of the electrode 3. The inner peripheral surface 123 of the inner sleeve 17 is a surface 123B parallel to the sleeve axis next to the taper surface 123A from the distal end portion toward the proximal end side, and then the inner diameter is slightly reduced, followed by the second The surface 123C is parallel to the sleeve axis. As will be described later, the second parallel surface 123 </ b> C is a current-carrying surface that comes into close contact with the outer peripheral surface 79 </ b> A of the large-diameter portion 79 of the electrode skirt portion 73 when the electrode 3 is attached to the inner sleeve 17. The inner diameter of the second parallel surface 123 </ b> C is slightly smaller than the outer diameter of the large diameter portion 79 of the electrode skirt portion 73. Further, the second parallel surface 123C has a sloped surface 123D that is chamfered so that the inner diameter of the second parallel surface 123C is smoothly reduced. When the electrode 3 is inserted into the inner sleeve 17, the slope surface 123 </ b> D abuts the chamfered surface 79 </ b> C of the base end outer periphery of the electrode skirt portion 73 to bend the tongue 77 inward, and thereby the electrode skirt portion 73. The large-diameter portion 79 can easily enter the second parallel surface 123C.

  When the base end side portion of the electrode 3 from the flange 83 is inserted into the space 121 inside the inner sleeve 17, the chamfered surface 79 C of the base end outer peripheral edge of the electrode skirt portion 73 first becomes the slope surface 123 D of the sleeve inner peripheral surface 123. Next, it slides along the slope surface 123D and enters further inside. At this time, the tongue 77 of the electrode skirt portion 73 is bent inward, and the large diameter portion 79 of the skirt portion 73 is contracted so as to enter the inside of the second parallel surface 123C of the sleeve inner peripheral surface 123, and the electrode skirt portion The outer peripheral surface (conducting surface) 79A of the large-diameter portion 79 of 73 is pressed against the second parallel surface (conducting surface) 123C of the sleeve inner peripheral surface 123 by the reaction force of the tongue 77 and the spring ring 81. The large-diameter portion 79 of the electrode skirt portion 73 enters the second parallel surface 123C of the sleeve inner peripheral surface 123 while the energizing surfaces 79A and 123C rub against each other. When the electrode 3 is completely inserted into the inner sleeve 17, the state shown in FIG. 11 is obtained, and the attachment of the electrode 3 to the inner sleeve 17 is completed. In this manner, the electrode 3 can be easily attached to the inner sleeve 17 by simply inserting it in the axial direction, and can be removed simply by pulling it in the axial direction. Therefore, the simple consumable item exchange as described above is possible.

  11, the cooling water comes out of the water conduit 15 as shown by the arrow, first cools the heat-resistant insert 4, and then turns back to return the outer peripheral surface of the water conduit 15 and the electrode 3 to the inside. The electrode 3 flows through the cooling water passage 21 between the peripheral surface and the base 3 while cooling the electrode 3. The cooling water passage 21 passes through the vicinity of the current-carrying surfaces 79 </ b> A and 123 </ b> C of the electrode 3 and the inner sleeve 17. A part of the cooling water in the cooling water passage 21 enters the slit 75 of the electrode skirt portion 73, passes through the slit 75, and is formed between the outer peripheral surface of the electrode 3 and the inner peripheral surface of the inner sleeve 17. The gap 125 is also filled (that is, the slit 75 and the gap 125 are also part of the cooling water channel). Therefore, the periphery of the contact surfaces 79A and 123C that are in close contact with each other is exposed to the cooling water. In other words, the closely energized surfaces 79 </ b> A and 123 </ b> C exist in the cooling water channels 21, 75, and 125. Further, the O-ring 91 of the electrode 3 is sandwiched between the flange 83 of the electrode 3 and the tapered surface 123A of the inner sleeve 17, and seals so that the cooling water in the gap 125 does not leak to the outside. The O-ring 91 also positions the electrode 3 in the axial direction.

  Even if some foreign matter adheres to the current-carrying surfaces 79A and 123C during the electrode mounting process described above, it is possible to ensure good contact between the current-carrying surfaces 79A and 123C. That is, when the electrode 3 is inserted into the inner sleeve 17, the electrode 3 moves in the axial direction with respect to the inner sleeve 17, whereby the current-carrying surfaces 79 </ b> A and 123 </ b> C of the electrode 3 and the inner sleeve 17 rub against each other. Due to this rubbing, some foreign matter adhering to the current-carrying surfaces 79A and 123C is crushed or buried in the current-carrying surface. As a result, in the attachment completion state shown in FIG. 11, the energizing surfaces 79 </ b> A and 123 </ b> C are pressed and brought into close contact with the tongue 77 and the reaction force of the spring ring 81. Further, even if there is a foreign matter remaining without being crushed, the foreign matter does not cause all the contact surfaces 79A and 123C to be poorly contacted, and the foreign matter is out of the plurality of tongues 77 of the electrode skirt portion 73. In the tongues 77 other than the existing tongue 77, the energizing surfaces 79A and 123C are in close contact. Thus, even if there is some foreign matter on the current-carrying surface, poor contact is unlikely to occur. In addition, even if there is some heat generation on the energized surface due to the contact resistance of the energized surface, cooling water flows in the vicinity and the surrounding area to strongly cool the energized surface, causing a problem of melting of the energized surface. do not do.

  In order to obtain a pressing force for bringing the current-carrying surface into close contact, the tongue 77 that is elastically deformed is provided on the electrode 3 side. However, this is not necessarily required, and an elastically deformed portion is provided on the inner sleeve 17 side. Alternatively, it may be provided on both the electrode 3 and the inner sleeve 17. However, it is advantageous to provide an elastically deforming portion on the electrode 3 side that is frequently replaced because there is no problem of metal fatigue due to repeated deformation. In addition, the shape of the current-carrying surfaces of the electrode 3 and the inner sleeve 17 is a cylindrical surface having a central axis common to the central axis of the electrode (the central axis of the torch). A conical surface having a central axis common to the central axis may be used (that is, the energizing surface may be tapered). Further, in addition to the energizing surface that is in close contact with the elastic force, an energizing surface that is pressed by a plane perpendicular to the torch axis may be provided. In this case, since there are two systems of energization surfaces, reliability against energization troubles is increased, and even if the electrodes have the same size, an advantage that a larger current can flow than an electrode having only one system of energization surfaces. There is.

  Next, characteristics regarding positional alignment between the electrode 3 and the nozzle 7 will be described.

  FIG. 12 schematically shows the principle of position alignment (particularly center axis alignment, that is, centering) between the electrode 3 and the nozzle 7 and is disassembled for easy understanding.

  The insulating guide 5 is fitted inside the nozzle 7 with an elastic O-ring 96 interposed therebetween, and the electrode 3 is fitted inside the insulating guide 5 with an elastic O-ring 93 interposed therebetween. The electrode 3 is fitted inside the inner inner sleeve 17, and the electrode 3 and the inner inner sleeve 17 come into contact with a tongue 77 having elasticity at the electrode base end portion, and at the tip end portion of the inner sleeve. An O-ring 91 having elasticity is sandwiched between them.

  The O-rings 91, 93, and 95 have a property that the shrinkage allowance of each part is substantially equal over the circumferential direction. Therefore, when the electrode 3 and the insulating guide 5 are fitted together with the O-ring 93 interposed therebetween, the central axis L1 of the electrode 3 and the central axis of the insulating guide 15 automatically and accurately coincide with each other due to the nature of the O-ring 93. To do. When the insulating guide 5 and the nozzle 7 are fitted together with the O-ring 95 interposed therebetween, the central axis of the insulating guide 15 and the central axis L2 of the nozzle 7 automatically and accurately coincide with each other due to the nature of the O-ring 95. To do. As a result, the center axis L1 of the electrode 3 and the center axis L2 of the nozzle 7 automatically coincide with each other with high accuracy. Next, when the electrode 3 is fitted to the inner inner sleeve 17 with the O-ring 91 in between, the center axis L3 of the inner inner sleeve 17 (that is, the central axis of the torch main body) and the electrode depend on the nature of the O-ring 91. The center axis L1 of 3 automatically matches. As a result, the center axis L1 of the electrode body 3, the center axis L2 of the nozzle 7, and the center axis L3 of the torch body automatically coincide with each other with high accuracy.

  The O-rings 91, 93, and 95 are accommodated in O-ring grooves formed on the outer peripheral surface or inner peripheral surface of each component, as shown in FIGS. The concentricity of the groove bottoms of these O-ring grooves has a large effect on the above-described centering, and therefore it is desirable to increase the accuracy to about 0.02 mm (refer to the bottom of the O-ring groove in a conventional general torch). Is about 0.05 mm).

  The retainer cap 13 is fixed to the fixing ring 37 of the torch main body by the rotating ring 39 while holding the shield cap 11 at the tip of the nozzle 7 at the tip. At this time, the retainer cap 13 only applies a pressing force to the nozzle 7 in a direction parallel to the central axes L1 to L3 described above, and does not apply a radial force or a rotational force. Further, the nozzle 7 is pressed against the nozzle pedestal 31 by the retainer cap 13, but the contact surface between the nozzle 7 and the nozzle pedestal 31 is a surface perpendicular to the axial direction. It only receives reaction force and does not receive radial force. As described above, there is no part on the outside of the nozzle 7 that applies a force other than the axial direction to the nozzle 7, particularly a force in the radial direction. That is, the nozzle 7 is in a free state without receiving an external force other than the force by the O-rings 91, 93, 95 in the radial direction. In other words, the nozzle 7 is in a free state so that position adjustment by the O-rings 91, 93 and 95 is allowed in the radial direction. Therefore, the position alignment action by the O-rings 91, 93, 95 described above works effectively without being disturbed by the external force in the radial direction. In this way, highly accurate positional alignment (that is, coincidence of the central axes) of the electrode 3 and the nozzle 7 in the radial direction by the O-rings 91, 93, and 95 is effectively performed without being disturbed by external force.

  On the other hand, the positioning between the nozzle 7 and the electrode 3 in the axial direction depends on the dimensions of the inner peripheral step 7C of the nozzle 7, the flange 83 of the electrode 3, and the insulating guide 5 sandwiched between the step 7 and the flange 83. Achieved. That is, the front end surface 5 A of the insulating guide 5 abuts on the step portion 7 C on the inner periphery of the nozzle 7, and the base end surface 5 B of the insulating guide 5 is pressed by the flange 83 of the electrode 3. As a result, the axial distance between the step 7c of the nozzle 7 and the flange 83 of the electrode 3 is determined by the axial length of the insulating guide 5, so that the relative position of the nozzle 7 and the electrode 3 in the axial direction is It is automatically determined with high accuracy.

  Further, it should be noted in the principle of the alignment described with reference to FIG. 12 that the O-rings 91, 93, 95 are positioned in the radial direction at the boundaries between the parts where the O-rings 91, 93, 95 are inserted. There is a sufficiently large clearance because of the alignment. That is, between the inner peripheral surface of the distal end portion of the inner sleeve 17 and the outer peripheral surface of the proximal end portion of the electrode 3, between the outer peripheral surface of the distal end portion of the electrode 3 and the inner peripheral surface of the insulating guide 5, and the insulating guide 5. There is a large clearance between the outer peripheral surface of the front end portion and the inner peripheral surface of the base end portion of the nozzle 7 so that these components do not directly touch each other. By this clearance, the above-described radial position alignment action by the O-rings 91, 93, 95 works effectively, and the parts can be easily separated and fitted together, so that the replacement work is easy. In addition, since the O-rings 91, 93, and 95 have a circular cross-sectional shape, there is no great resistance when parts are separated or fitted together, which also facilitates the replacement work.

  The O-rings 91, 93, and 95 are not limited to this. As an alternative, a member having elasticity corresponding to an O-ring can be used. Alternatively, instead of a ring member that continuously exists on the inner peripheral surface or outer peripheral surface of the component, such as an O-ring, a plurality of elastic members arranged at a plurality of locations in the circumferential direction of the inner peripheral surface or outer peripheral surface of the component You may make it take radial position alignment by using the block and performing the equal elastic expansion-contraction of these elastic blocks in multiple places of the circumference.

  As mentioned above, although this invention was demonstrated based on one Embodiment, it is clear that this invention is not limited to this.

Sectional drawing along the central axis of the plasma torch for cutting concerning one Embodiment of this invention. Sectional drawing of a torch main body when the retainer cap 13 is removed from the plasma torch. Sectional drawing of the set of the retainer cap 13 and the consumables removed together with it when the retainer cap 13 is removed from the plasma torch. Sectional drawing of 3 components set which couple | bonded the electrode, the insulation guide, and the nozzle. Sectional drawing of the separated electrode, insulation guide, and nozzle. The flowchart which shows the procedure of consumables exchange. The perspective view of the plasma processing machine concerning one Embodiment of this invention provided with the consumables automatic change apparatus. Sectional drawing of the principal part of a consumables automatic change apparatus. Sectional drawing of an electrode. Sectional drawing of the part which attaches the electrode of a torch main body. Sectional drawing of the part which attached the electrode to the torch main body. A typical sectional view showing a principle of position alignment of an electrode and a nozzle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plasma torch 3 Electrode 5 Insulation guide 7 Nozzle 11 Shield cap 13 Retainer cap 15 Water guide pipe 17 Inner sleeve 29 Outer sleeve 37 Fixed ring 39 Rotating ring 91, 93, 95 O-ring

Claims (8)

A plasma torch, a work table, and a moving mechanism for moving the plasma torch on the work table;
The plasma torch includes a torch body attached to the moving mechanism, and a detachable part attached in a detachable manner to the torch body,
The detachable portion includes an electrode, a nozzle disposed so as to surround the electrode, an insulator interposed between the electrode and the nozzle, and a retainer that accommodates the electrode, the nozzle, and the insulator inside. With a cap,
The torch body includes an electrode connecting portion coupled to the electrode, a nozzle connecting portion coupled to the nozzle, a retainer cap connecting portion coupled to the retainer cap, a cooling water pipe, and a plasma gas pipe. Have
As the retainer cap is coupled to the retainer cap connecting portion along a predetermined path, the electrode and the nozzle are coupled to the electrode connecting portion and the nozzle connecting portion, respectively, and the retainer cap is attached to the retainer cap connecting portion. The connection between the electrode and the electrode connection portion so that the electrode and the nozzle are detached from the electrode connection portion and the nozzle connection portion, respectively, in accordance with an operation of removing the retainer cap connection portion and moving away from the retainer cap connection portion along a predetermined path. A structure and a coupling structure of the nozzle and the nozzle connection portion are configured,
The electrode, the insulator, the nozzle, and the retainer cap are coupled to each other, and the coupling force between them is the coupling force between the electrode and the electrode connecting portion and the nozzle and the nozzle connecting portion. Stronger than any of the binding forces between
Accordingly, by attaching and removing the retainer cap to the retainer cap connecting portion, all the parts of the detachable portion can be attached to and detached from the torch body together. Automatic for disposing the retainer cap from the torch body of the plasma torch, and then attaching another retainer cap to the torch body, which is disposed at a predetermined location within the movable range of the plasma torch by the moving mechanism Exchange device,
The plasma processing machine according to claim 1, further comprising: The plasma processing machine according to claim 1, wherein the electrode or the nozzle is replaced.
Moving the plasma torch to an exchange work place;
Removing the retainer cap from the torch body of the plasma torch at the replacement work place to remove all parts of the detachable part together from the torch body;
Replacing the electrode or the nozzle in the detachable part with a new one;
Attaching all the parts of the detachable part to the nozzle body together by attaching the retainer cap of the detachable part after the electrode or the nozzle is replaced with a new one at the replacement work place. When,
Consumables replacement method for plasma processing machine having A torch body having a cooling water pipe and a plasma gas pipe, and a detachable part attached to the torch body in a detachable state,
The detachable portion includes an electrode, a nozzle disposed so as to surround the electrode, an insulator interposed between the electrode and the nozzle, and a retainer that accommodates the electrode, the nozzle, and the insulator inside. With a cap,
The torch body further includes an electrode connection portion coupled to the electrode, a nozzle connection portion coupled to the nozzle, and a retainer cap connection portion coupled to the retainer cap,
As the retainer cap is coupled to the retainer cap connecting portion along a predetermined path, the electrode and the nozzle are coupled to the electrode connecting portion and the nozzle connecting portion, respectively, and the retainer cap is attached to the retainer cap connecting portion. The connection between the electrode and the electrode connection portion so that the electrode and the nozzle are detached from the electrode connection portion and the nozzle connection portion, respectively, in accordance with an operation of removing the retainer cap connection portion and moving away from the retainer cap connection portion along a predetermined path. A structure and a coupling structure of the nozzle and the nozzle connection portion are configured,
The electrode, the insulator, the nozzle, and the retainer cap are coupled to each other, and the coupling force between them is the coupling force between the electrode and the electrode connecting portion and the nozzle and the nozzle connecting portion. Stronger than any of the binding forces between
Accordingly, by attaching and removing the retainer cap to and from the retainer cap connecting portion, all the parts of the detachable portion can be attached to and detached from the torch body together.   The plasma torch according to claim 4, wherein the electrode and the nozzle are individually separable from the retainer cap.   The plasma torch according to claim 4, wherein the electrode, the nozzle, and the retainer cap are coupled to each other by a coupling structure using an elastic body.   The electrode and the electrode connection part each have a current-carrying surface that is in contact with each other to ensure electrical connection between them, and the current-carrying surfaces of the electrode and the electrode connection part are at least of the electrode and the electrode connection part. The plasma torch according to claim 4, wherein the plasma torches are in contact with each other with a pressing force generated by deformation of an elastic deformation portion provided on one side. The plasma torch according to claim 4, wherein the electrode or the nozzle is replaced.
Removing all retainer parts from the torch body together by removing the retainer cap from the torch body of the plasma torch;
Replacing the electrode or the nozzle in the detachable part with a new one;
Attaching all the parts of the detachable part to the nozzle body together by attaching the retainer cap of the detachable part after the electrode or the nozzle is replaced with a new one at the replacement work place. When,
A method for exchanging consumables for a plasma torch.

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