JP2009195883A - Thermal spray gun device and metal powder discharging method in thermal spray gun device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal spray gun device capable of preventing the energization at a part except between electrodes by discharging metal powder produced in the formation of molten drops and deposited around the pilot nozzle out of a gun head body. <P>SOLUTION: In the thermal spray gun device for spraying the molten drops melted by passing current between a cathode 2 and a metallic material 8 to a body to be sprayed as a thermal spray jet flow 9 by the impulse of atomizing air jetted from a second jetting port 6 formed in a pilot nozzle 3, the metal powder in soot, fume or the like produced in the formation of the molten drops and deposited around the pilot nozzle is discharges out of a gun head body by the atomized air supplied to a branched flow passage 18 branched from the atomized air supply path 7. The discharge of the metal powder out of the gun head body is carried out by opening a valve 19 provided in the atomized air supply path 7 after finishing of the spray of the thermal spray jet flow 9 to the body to be sprayed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a spray gun apparatus for spraying a molten metal material in a spray state to form a coating on a sprayed body, and a method for discharging the metal powder. The present invention relates to a technique for removing metal powder from the gun head body.

  For example, a spray gun apparatus that forms an alloy spray layer on an inner wall of a cylinder bore of an engine block has been proposed (see, for example, Patent Document 1).

  Among this type of thermal spray gun apparatus, the torch classified as an electric type melts the metal material by energizing between the electrodes, but the soot and fumes generated at the time of melting the metal become dielectrics and energize other than between the electrodes. Sometimes. When energizing other than between the electrodes, the torch may be melted by the generated heat.

In order to solve this problem, it is conceivable to blow air blow on the nozzle tip of the torch, or to blow soot and fumes by constantly blowing air to the nozzle tip.
JP 2006-322049 A

  However, when air blow is blown from the nozzle tip, air and gas path clogging due to backflow occurs, and soot and fume discharge effects cannot be expected.

  Therefore, the present invention provides a thermal spray gun apparatus and a method for discharging the metal powder that can prevent the metal powder generated at the time of droplet formation and collected around the pilot nozzle from being discharged to the outside of the gun head body and energized at a portion other than between the electrodes The purpose is to do.

  In order to solve the above-described problems, the spray gun apparatus of the present invention sprays atomized air flowing through an atomized air supply path provided in the gun head body with metal powder generated at the time of droplet formation and collected around the pilot nozzle. Thus, a metal powder discharging means for discharging the gun head main body is provided.

  According to the present invention, since the gun powder main body is provided with the metal powder discharging means, atomized air can be blown to the metal powder generated at the time of droplet generation and accumulated around the pilot nozzle to be discharged out of the gun head main body. Thereby, it can avoid that the metal powder collected around the pilot nozzle becomes a conductor and is electrically connected to the cathode, thereby preventing the thermal spray gun from being melted.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings.

“First Embodiment”
FIG. 1 is a cross-sectional view of the thermal spray gun apparatus of the first embodiment. This spray gun apparatus is an apparatus that forms a sprayed coating on the inner surface of a bore by spraying a droplet formed by melting a metal material on the inner surface of a bore of an aluminum alloy cylinder block in an automobile engine, for example. .

  As shown in FIG. 1, the thermal spray gun apparatus is provided with a gun head main body 1 as a main body, a cathode 2 provided on the gun head main body 1, a front side of the cathode 2, and energizes the cathode 2 only at the time of ignition. A pilot nozzle 3 for generating a pilot arc, a spray gas supply passage 5 for supplying a spray gas (plasma gas) to a first injection hole 4 formed at the center of the pilot nozzle 3, and a first injection of the pilot nozzle 3. An atomizing air supply passage 7 for supplying atomized air to a plurality of second ejection holes 6 formed around the hole 4, and the cathode 2 in an atmosphere of a spray gas ejected from the first ejection hole 4. Metal material 8 that is melted by energization, and metal that blows atomized air out of the gun head body to discharge the metal powder that is generated at the time of droplet formation and collects around the pilot nozzle And a discharge means, and is configured to blow onto the sprayed body droplet melted at momentum atomizing air ejected from the second ejection hole 6 as spraying jet (spray flame) 9.

  The gun head main body 1 serves as a main body of the spray gun, and is made of, for example, copper. The cathode 2 is fixed to the collet 10 by a collet cap 11 that is screwed to a collet 10 attached to the gun head body 1. The cathode 2 is made of tungsten, for example. The collet 10 is made of copper like the gun head body 1, and the collet cap 11 is made of iron.

  Since the pilot nozzle 3 functions as an anode for generating a pilot arc by energizing the cathode 2 only at the time of ignition, it is made of, for example, conductive copper. The pilot nozzle 3 is provided in front of the cathode 2 and has a first ejection hole 4 for ejecting a spray gas at the center thereof. The pilot nozzle 3 is formed with a second ejection hole 6 for ejecting atomized air. A plurality of second ejection holes 6 are formed at predetermined intervals so as to form a circular shape around the first ejection hole 4. The plurality of second ejection holes 6 eject atomized air so as to gather at one point on the extension line of the first ejection holes 4.

  The pilot nozzle 3 is mounted on a baffle plate 12 made of resin and attached to the gun head body 1. The pilot nozzle 3 is fixed to the gun head body 1 by a nozzle ring 13 and a pressing plate 14 made of resin.

  The thermal spray gas supply path 5 passes through the outer periphery of the collet cap 11 from the thermal spray gas introduction hole 15 through the first thermal spray gas path 5a that leads from one side of the gun head body 1 to the thermal spray gas introduction hole 15 formed in the collet 10. And a second sprayed gas passage 5b formed in the baffle plate 12 leading to the front of the cathode 2. The thermal spray gas guided to the front of the cathode 2 is ejected from the first ejection hole 4 formed in the pilot nozzle 3 to the front of the head.

  The atomizing air supply path 7 includes a first atomizing air path 7 a that leads from one side of the gun head body 1 to an atomizing air introduction hole 16 formed between the baffle plate 12 and the gun head body 1, and an atomizing air introduction hole 16. And a second atomizing air passage 7b formed in the baffle plate 12 leading to the second ejection hole 6 formed in the pilot nozzle 3.

  The metal material 8 is sent to the front of the first ejection hole 4 and the second ejection hole 6 from the material supply path 17 of the metal material supply plate 16 provided in front of the holding plate 14. The metal material 8 is formed as a wire made of carbon steel, for example, and is sequentially fed by a feeding device (not shown). The metal material 8 is melted by being energized with the cathode 2 described above in an atmosphere of spraying gas ejected from the first ejection holes 4. The molten droplets are ejected forward by the force of atomized air ejected from the second ejection holes 6 to form a thermal spray jet (thermal spray frame) 9. By spraying this thermal spraying jet 9 onto the bore inner surface of the cylinder block, a thermal spray coating is formed on the bore inner surface.

  The metal powder discharging means includes a branch flow path 18 branched from the atomizing air supply path 7 and a valve 19 for selectively supplying atomized air to the branch flow path 18 and the atomizing air supply path 7. The branch flow path 18 is formed so that the outlet 20 leads to a minute gap between the pilot nozzle 3 and a portion surrounding the outer periphery of the pilot nozzle 3 by branching from the atomizing air supply path 7. The gap is a fine gap generated at the interface between the parts when the parts such as the gun head body 1, the baffle plate 12, the pilot nozzle 3, and the holding plate 14 are assembled.

  In FIG. 1, the outlet 20 of the branch flow path 18 faces a discharge hole 22 formed across a part of the outer periphery of the pilot nozzle and a part of the outer periphery of the baffle plate. In this example, the discharge hole 22 is formed and the outlet 20 of the branch channel 18 is provided in the discharge hole 22, but the discharge hole 22 may not be provided.

  The baffle plate 12 is provided with a plurality of seal members 21 for preventing leakage of the spray gas from the spray gas supply path 5 and the atomized air from the atomizing air supply path 7. For the seal member 21, for example, an O-ring is employed.

  In the spray gun apparatus configured as described above, first, the cathode 2 and the pilot nozzle 3 functioning as the anode are energized to generate a pilot arc. After the pilot arc is generated, the cathode 2 and the pilot nozzle 3 are not energized. Next, electricity is applied between the cathode 2 and the metal material 8. At this time, the thermal spray gas is ejected from the first ejection holes 4 through the thermal spray gas supply path 5, thereby creating an atmosphere in which electricity can easily be generated between the metal material 8 and the cathode 2. By doing so, it becomes easy to energize between the cathode 2 and the metal material 8. Next, the metal material 8 is sequentially sent out from the material supply path 17, and the metal material 8 and the cathode 2 are energized to melt the metal material 8. Molten droplets of the molten metal material 8 become a thermal spray jet 9 with the force of atomized air ejected from the second ejection holes 6 through the atomized air supply passage 7.

  When the spray jet 9 is ejected onto the bore inner surface of the cylinder block to form the spray coating, the valve 19 provided in the atomizing air supply path 7 is switched to the branch path 18. When the jet stream 9 is continuously ejected, metal powder such as soot and fume is generated, and this metal powder accumulates around the outer periphery of the pilot nozzle 3. Since the metal powder is a fine particle, it enters from the interface between the pilot nozzle 3 and the nozzle ring 13 or the second ejection hole 6 and surrounds the outer periphery of the pilot nozzle 3 with the holding plate 14 and the baffle plate 12 and the pilot. It enters a fine gap between the nozzle 3. When metal powder accumulates, the metal powder functions as a conductive material and conducts with the cathode 2, and the deposited portion is melted.

  Therefore, if the valve 19 is switched to the branch flow path 18 after the spraying of the spray jet 9 to the sprayed body is completed, the supply of the atomized air to the second ejection hole 6 is stopped, but only to the branch flow path 18. Atomized air flows. The atomized air that has flowed through the branch flow path 18 is ejected from an outlet 20 provided in a fine gap between the pilot nozzle 3 where metal powder tends to accumulate and a portion surrounding the outer periphery of the pilot nozzle 3. As a result, the metal powder deposited in the fine gaps around the outer periphery of the pilot nozzle 3 can be discharged out of the gun head body.

  According to the spray gun apparatus configured as described above, by providing the gun head main body 1 with the metal powder discharging means, the atomized air is blown to the metal powder generated when the droplets are generated and collected around the pilot nozzle. Therefore, it can be avoided that the metal powder collected around the pilot nozzle becomes a conductor and is electrically connected to the cathode 2, and the spray gun can be prevented from being damaged.

  Further, according to the thermal spray gun apparatus of the present embodiment, the metal powder discharging means is branched from the atomizing air supply path 7, and atomized air is selected for the branching path 18 and the atomizing air supply path 7. Therefore, the existing atomized air can be used. In other words, there is no need to use air that blows off metal powder by blowing it to the tip of the nozzle as in the past, and it is possible to prevent backflow caused by the blown air and clogging of the path. Can be discharged.

  In addition, according to the spray gun apparatus of the present embodiment, the outlet 20 of the branch flow path 18 is provided in a fine gap between the pilot nozzle 3 and a portion surrounding the outer periphery of the pilot nozzle 3, and thus the deposit 20 is deposited in the gap. Since atomized air is directly blown onto the metal powder to be performed, the metal powder can be discharged out of the gun head body without difficulty.

  Further, according to the spray gun apparatus of the present embodiment, the atomized air is supplied to the branch channel 18 by opening the valve 19 after completion of spraying the sprayed jet 9 to the sprayed object. When the thermal spray jet 9 is ejected next, it can be returned to a state without metal powder.

  Further, according to the metal powder discharging method of the present embodiment, after the spraying of the sprayed jet 9 to the spray target is completed, the metal powder generated at the time of forming the droplet and collecting around the pilot nozzle is branched from the atomizing air supply path 7. Since atomized air is blown and discharged out of the gun head main body through the branched flow path 18, metal powder such as soot and fumes that are easily connected to the cathode 2 can be eliminated.

“Second Embodiment”
FIG. 2 is a cross-sectional view of the thermal spray gun apparatus of the second embodiment. The second embodiment is an example in which the outlet 20 of the branch flow path 18 is arranged in a fine gap between the outer periphery of the baffle plate 12 that fixes the pilot nozzle 3 and the gun head body 1 facing the outer periphery. In FIG. 2, an outlet 20 of the branch flow path 18 is provided in front of a seal member 21 that seals between the gun head main body 1 and the baffle plate 12.

  In the thermal spray gun apparatus of the second embodiment, as in the first embodiment, after spraying the thermal spray jet 9 to the sprayed body, the valve 19 is opened and atomized air is supplied to the branch flow path 18, so that the pilot nozzle 3 Metal powder accumulated in minute gaps around the outside can be discharged out of the gun head body.

  Although specific embodiments to which the present invention is applied have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made.

FIG. 1 is a cross-sectional view of the thermal spray gun apparatus of the first embodiment. FIG. 2 is a cross-sectional view of the thermal spray gun apparatus of the second embodiment.

Explanation of symbols

1 ... Gun head body 2 ... Cathode 3 ... Pilot nozzle (anode)
DESCRIPTION OF SYMBOLS 4 ... 1st ejection hole 5 ... Spraying gas supply path 6 ... 2nd ejection hole 7 ... Atomizing air supply path 8 ... Metal material 9 ... Thermal spraying jet (spraying flame | frame)
DESCRIPTION OF SYMBOLS 10 ... Collet 12 ... Baffle plate 14 ... Holding plate 17 ... Material supply path 18 ... Branch flow path 19 ... Valve 20 ... Outlet

Claims (5)

A cathode provided on the gun head body;
A pilot nozzle that is provided in front of the cathode and serves as an anode for generating a pilot arc by energizing the cathode only during ignition;
A spray gas supply passage for supplying a spray gas to the first ejection hole formed at the center of the pilot nozzle;
An atomizing air supply path for supplying atomized air to a plurality of second ejection holes formed around the first ejection hole of the pilot nozzle;
A supply path for supplying a metal material to be melted by energizing the cathode in an atmosphere of a spray gas ejected from the first ejection holes;
A spray gun apparatus for spraying a molten droplet melted by the force of atomized air ejected from the second ejection hole as a thermal spray jet onto a sprayed body,
A thermal spray gun apparatus comprising: metal powder discharging means for discharging metal powder generated at the time of generating the droplets and collecting around the pilot nozzle to the outside of the gun head body by blowing atomized air. The thermal spray gun apparatus according to claim 1,
The metal powder discharging means includes a branch flow path branched from the atomized air supply path, and a valve for selectively supplying atomized air to the branch flow path and the atomized air supply path. Thermal spray gun equipment. The thermal spray gun apparatus according to claim 2,
The spray gun apparatus characterized in that an outlet of the branch flow path is provided in a fine gap between the pilot nozzle and a portion surrounding the outer periphery of the pilot nozzle. The thermal spray gun apparatus according to claim 2 or 3,
The spray gun apparatus characterized in that the valve is opened after the spraying jet is sprayed onto the sprayed body and atomized air is supplied to the branch flow path. In the method for discharging metal powder in a spray gun apparatus in which droplets obtained by ejecting atomized air and melting a metal material are sprayed onto a sprayed body as a spray spray,
After the spraying of the sprayed jet to the sprayed body, the atomized air is blown out from the gun head main body through a branch flow path branched from the atomized air supply path to the metal powder generated at the time of droplet formation and accumulated around the pilot nozzle. A method for discharging metal powder in a thermal spray gun apparatus, characterized in that

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