Shielding gas ejection device and processing device

Abstract

This shielding gas ejecting device is provided with a nozzle main body extending along an axis, an inner shielding gas ejection path which is formed inside the nozzle main body and which opens on the axis, an outer shielding gas ejection path surrounding the inner shielding gas ejection path from the periphery thereof, and an intermediate shielding gas ejection path provided between the inner shielding gas ejection path and the outer shielding gas ejection path, wherein the flow rate of intermediate shielding gas ejected from the intermediate shielding gas ejection path is less than the flow rate of inner shielding gas ejected from the inner shielding gas ejection path and outer shielding gas ejected from the outer shielding gas ejection path.

Description

Technical Field

[0001] The present disclosure relates to a shielding gas ejection device and a processing device. This application claims priority based on Japanese Patent Application No. 2021-013504 filed in Japan on January 29, 2021, the content of which is incorporated herein by reference.

Background Art

[0002] For example, in processing devices including a layered manufacturing device or a build-up welding device, it is necessary to prevent oxidation caused by the base material (workpiece) coming into contact with air. For this reason, these processing devices are provided with a mechanism for supplying shielding gas to the surface of the base material. As a mechanism of this type, Patent Document 1 below discloses a device that ejects shielding gas from around a laser irradiation unit. In addition, a configuration in which shielding gas is directly blown onto the surface of the base material from an annular nozzle opening to protect the base material is also known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, when shielding gas is blown onto the surface of the base material as described above, the shielding gas forms a layer that flows so as to spread outward on the surface of the base material. On the other hand, inside this layer, a circulation vortex is generated due to being dragged by the flow of the shielding gas. Such a circulation vortex causes fluctuations in the flow of the shielding gas. As a result, the shielding gas layer may be locally or intermittently broken, and there is a risk that a sufficient shielding effect cannot be obtained.

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to provide a shielding gas ejection device and a processing device that can perform shielding more stably.

Means for Solving the Problem

[0006] To solve the above problems, the shielding gas ejection device according to the present disclosure includes a nozzle body extending along an axis, an inner shielding gas ejection path formed at the tip of the nozzle body and opening annularly around the axis, an outer shielding gas ejection path surrounding the inner shielding gas ejection path from the periphery, and an intermediate shielding gas ejection path provided between the inner shielding gas ejection path and the outer shielding gas ejection path. The flow velocity of the intermediate shielding gas ejected from the intermediate shielding gas ejection path is lower than the flow velocities of the inner shielding gas ejected from the inner shielding gas ejection path and the outer shielding gas ejected from the outer shielding gas ejection path.

Effect of the Invention

[0007] According to the present disclosure, it is possible to provide a shielding gas ejection device and a processing device that can perform shielding more stably.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0009] <First Embodiment> (Configuration of the Processing Device) Hereinafter, the processing apparatus 200 and the shielding gas ejection apparatus 100 according to the first embodiment of the present disclosure will be described with reference to FIG. 1. The processing apparatus 200 includes a processing unit 90 and a shielding gas ejection apparatus 100.

[0010] As the processing unit 90, one appropriately selected from a plurality of types of apparatuses such as a laser irradiation apparatus for performing additive manufacturing and a welding nozzle for performing build-up welding is applied.

[0011] (Configuration of Shielding Gas Ejection Apparatus) The shielding gas ejection apparatus 100 is used to inject a shielding gas against an object to be processed (workpiece 80) by the above-described processing unit 90 to prevent oxidation and surface deterioration of the object. The shielding gas ejection apparatus 100 includes a nozzle body 10, an inner shielding gas ejection passage 20, an intermediate shielding gas ejection passage 30, and an outer shielding gas ejection passage 40.

[0012] The nozzle body 10 has a main portion 11, a reduced-diameter portion 12, a chamber formation portion 13, and a partition plate 15. The main portion 11 has a columnar shape extending along the axis O. The diameter dimension of the main portion 11 is constant over the entire region in the direction of the axis O. The reduced-diameter portion 12 is integrally provided below the main portion 11 (that is, on the side where the workpiece 80 is located). The reduced-diameter portion 12 has a tapered shape in which the diameter dimension gradually decreases from top to bottom.

[0013] On the outer peripheral side of the reduced-diameter portion 12, a chamber forming portion 13 is provided. The chamber forming portion 13 has an annular shape that projects radially outward from the outer peripheral surface of the reduced-diameter portion 12. A space (chamber 14) is formed inside the chamber forming portion 13. This chamber 14 is a space for guiding the outer shield gas described later. A partition plate 15 is provided in the chamber 14. The partition plate 15 projects upward from the upward-facing surface of the inner surface of the chamber 14 and has an annular shape centered on the axis O. The chamber 14 is partitioned into an outer peripheral side region and an inner peripheral side region by the partition plate 15. Also, a gap extending in the direction of the axis O is formed between the upper end surface of the partition plate 15 and the inner wall of the chamber 14.

[0014] The inner shield gas ejection path 20 extends in the direction of the axis O across the above-described main portion 11 and the reduced-diameter portion 12. The inner shield gas ejection path 20 opens on the lower end surface 11b of the reduced-diameter portion 12. The opening shape of the inner shield gas ejection path 20 is circular as an example. Also, the flow path cross-sectional area of the inner shield gas ejection path 20 gradually decreases from top to bottom. Inner shield gas is supplied to this inner shield gas ejection path 20 through an inner shield gas supply path 20a formed on the upper end surface of the main portion 11. Also, the above-described processing portion 90 projects inside the inner shield gas ejection path 20. That is, various processes by the processing portion 90 are performed through this inner shield gas ejection path 20.

[0015] The intermediate shielding gas ejection path 30 extends across the main portion 11 and the reduced-diameter portion 12 and surrounds the inner shielding gas ejection path 20 from the outer peripheral side. That is, the intermediate shielding gas ejection path 30 is formed over the entire circumferential direction with the axis O as the center. The outlet of the intermediate shielding gas ejection path 30 opens on the lower end surface 11b. This opening is annular with the axis O as the center. Further, among the intermediate shielding gas ejection path 30, the portion passing through the main portion 11 extends in the direction of the axis O, while the portion passing through the reduced-diameter portion 12 extends in a direction approaching the axis O as it goes from above to below. The intermediate shielding gas is supplied to the intermediate shielding gas ejection path 30 from an inlet opening on the upper end surface 11a.

[0016] The outer shielding gas ejection path 40 extends downward from the above-described chamber 14. That is, the outer shielding gas ejection path 40 is provided further on the outer peripheral side of the intermediate shielding gas ejection path 30. The outer shielding gas ejection path 40 is formed over the entire circumferential direction with the axis O as the center. The outer shielding gas ejection path 40 extends in a direction approaching the axis O as it goes from above to below. Further, the outlet of the outer shielding gas ejection path 40 is located above the lower end surface 11b. The outer shielding gas guided from the chamber 14 flows through the outer shielding gas ejection path 40. The outer shielding gas is supplied to the chamber 14 through an outer shielding gas supply path 40a formed on the side surface 13a of the chamber forming portion 13. The outer shielding gas supply path 40a is provided, for example, only at one location in the circumferential direction. It is also possible to provide the outer shielding gas supply path 40a at a plurality of locations in the circumferential direction at intervals. The outer shielding gas supplied from the outer shielding gas supply path 40a diffuses over the entire circumferential direction by colliding with the partition plate 15. Thereby, it is possible to eject the outer shielding gas under a uniform flow rate distribution in the circumferential direction.

[0017] In the shielding gas ejection device 100 configured as described above, the flow rate of the inner shielding gas, the outer shielding gas, and the intermediate shielding gas is adjusted so as to decrease in this order. Note that the inner shielding gas, the outer shielding gas, and the intermediate shielding gas may be supplied from the same supply source and then the flow rate may be made different as described above using various valves and the like, or gases with different flow rates may be supplied from mutually different supply sources respectively.

[0018] (Function and effect) Next, the operations of the processing device 200 and the shielding gas ejection device 100 described above will be explained. When operating the processing device 200, first the shielding gas ejection device 100 is driven to form a shielding region on the surface of the workpiece 80. Next, various processes are performed on the workpiece 80 by driving the processing unit 90.

[0019] Here, if only the inner shielding gas and the outer shielding gas are blown onto the surface of the workpiece 80, these shielding gases form a layer that flows and spreads outward on the surface of the workpiece 80 (solid arrows in FIG. 1). On the other hand, inside this layer, a circulating vortex is generated due to being dragged by the flow of the shielding gas (broken arrows in FIG. 1). There is a risk that such a circulating vortex will cause fluctuations in the flow of the shielding gas. When fluctuations occur in the flow, the shielding is locally broken and external air flows into the inside of the shielding gas layer. As a result, oxidation and surface deterioration may occur on the workpiece 80.

[0020] However, in the above configuration, an intermediate shielding gas ejection path 30 is provided between the inner shielding gas ejection path 20 and the outer shielding gas ejection path 40. When this intermediate shielding gas is ejected, the entrainment flow that causes the above-described circulating vortex rides on the flow of the intermediate shielding gas and flows out to the surroundings. As a result, it becomes difficult to form a circulating vortex. Thereby, the possibility of fluctuations occurring in the flow of the shielding gas can be reduced. As a result, it is possible to avoid the shielding by the shielding gas being broken. Therefore, it becomes possible to perform the processing operation more stably.

[0021] Also, the flow rate of the intermediate shielding gas is smaller than that of the outer shielding gas and the inner shielding gas. Therefore, it is also possible to reduce the possibility that the original flow of these outer shielding gas and inner shielding gas is inhibited by the intermediate shielding gas. Thereby, the machining operation can be performed more stably.

[0022] Furthermore, in the above configuration, the intermediate shielding gas ejection path 30 and the outer shielding gas ejection path 40 are configured to eject the intermediate shielding gas and the outer shielding gas in a direction approaching the axis O as they go from above (upstream side) to below (downstream side). Thereby, a more strongly shielded space can be formed in the region on the workpiece 80 including the axis O by the intermediate shielding gas and the outer shielding gas.

[0023] The first embodiment of the present disclosure has been described above. Note that various changes and modifications can be made to the above configuration without departing from the gist of the present disclosure. For example, when applying the shielding gas ejection device 100 to the additive manufacturing apparatus listed as an example of the processing unit 90 in the first embodiment, it is possible to form a supply path for supplying powder that becomes a material for additive manufacturing between the inner shielding gas ejection path 20 and the intermediate shielding gas ejection path 30.

[0024] Also, it is possible to use a perforated plate as the partition plate 15 described above. Also in this case, it is possible to diffuse the outer shielding gas supplied from the outer shielding gas supply path 40a in the circumferential direction and eject the outer shielding gas under a uniform flow rate distribution.

[0025] <Second Embodiment> Next, a second embodiment of the present disclosure will be described with reference to FIG. 2. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and detailed descriptions thereof are omitted. As shown in the figure, in this embodiment, a vane 18 is provided at an intermediate position of the outer shield gas ejection path 40. The vane 18 extends from one side in the circumferential direction to the other side as it goes from above to below. Further, a plurality of vanes 18 are arranged at intervals in the circumferential direction. By providing these vanes 18, the outer shield gas ejection path 40 is capable of ejecting the outer shield gas so as to swirl around the axis O.

[0026] According to the above configuration, since the outer shield gas swirls around the axis O, the flow direction when the outer shield gas collides with the workpiece 80 is limited, and the flow field is stabilized. For this reason, the amount of variation in the flow from the space on the inner circumferential side of the outer shield gas toward the outside is reduced. As a result, the flow flowing backward from the outside into the inner circumferential side space is reduced, and the shielding performance on the surface of the workpiece 80 can be further improved. As a result, the machining operation can be performed more stably. Further, according to the above configuration, the shielding performance can be improved under a simple structure only by providing a plurality of vanes 18 in the outer shield gas ejection path 40. Thereby, an increase in the cost related to the manufacture and maintenance of the apparatus can be suppressed.

[0027] The second embodiment of the present disclosure has been described above. Note that various changes and modifications can be made to the above configuration without departing from the gist of the present disclosure. For example, as shown in FIG. 3, it is also possible to configure the outer shield gas supply path 40a (supply flow path) to extend in a direction having a circumferential component with respect to the axis O. Also in this case, the outer shield gas can be ejected so as to swirl around the axis O. Note that the example in FIG. 3 shows a configuration in which the outer shield gas supply path 40a is provided only at one location in the circumferential direction. However, it is also possible to provide the outer shield gas supply path 40a at a plurality of locations in the circumferential direction.

[0028] Also, as shown in FIG. 4, the outer shield gas ejection path 40 can be configured to extend from one side in the circumferential direction to the other side as it goes from the upstream side to the downstream side. More specifically, it is possible to adopt a configuration in which a plurality of guide plates 19 are provided at intervals in the circumferential direction at the outlet of the outer shield gas ejection path 40. These guide plates 19 extend from one side in the circumferential direction to the other side as they go from the upstream side to the downstream side. Also with this configuration, it is possible to eject the outer shield gas so as to swirl around the axis O.

[0029] <Addendum> The shield gas ejection device 100 described in each embodiment is understood as follows, for example.

[0030] (1) The shield gas ejection device 100 according to the first aspect includes a nozzle body 10 extending along the axis O, an inner shield gas ejection path 20 formed inside the nozzle body 10 and opening on the axis O, an outer shield gas ejection path 40 surrounding the inner shield gas ejection path 20 from the periphery, and an intermediate shield gas ejection path 30 provided between the inner shield gas ejection path 20 and the outer shield gas ejection path 40. The flow velocity of the intermediate shield gas ejected from the intermediate shield gas ejection path 30 is lower than the flow velocities of the inner shield gas ejected from the inner shield gas ejection path 20 and the outer shield gas ejected from the outer shield gas ejection path 40.

[0031] Here, when only the inner shield gas and the outer shield gas are blown onto the surface of the object, these shield gases form a layer that flows and spreads outward on the surface of the object. On the other hand, inside this layer, a circulating vortex is generated due to being dragged by the flow of the shield gas. Such a circulating vortex causes fluctuations in the flow of the shield gas. However, in the above configuration, an intermediate shield gas ejection path 30 is provided between the inner shield gas ejection path 20 and the outer shield gas ejection path 40. When this intermediate shield gas is ejected, the entrainment flow that causes the above-mentioned circulating vortex diffuses around along the flow of the intermediate shield gas. As a result, it becomes difficult to form a circulating vortex. Thereby, the possibility of fluctuations occurring in the flow of the shield gas can be reduced.

[0032] (2) In the shield gas ejection device 100 according to the second aspect, the intermediate shield gas ejection path 30 and the outer shield gas ejection path 40 are configured to eject the intermediate shield gas and the outer shield gas in a direction approaching the axis O from the upstream side to the downstream side.

[0033] According to the above configuration, a more strongly shielded space can be formed in the region including the axis O by the intermediate shield gas and the outer shield gas.

[0034] (3) In the shield gas ejection device 100 according to the third aspect, the outer shield gas ejection path 40 ejects the outer shield gas so as to swirl around the axis O.

[0035] According to the above configuration, since the outer shield gas swirls around the axis O, the flow direction when the outer shield gas collides with the object is limited, and the flow field is stabilized. For this reason, fluctuations in the flow from the inner peripheral side space of the outer shield gas toward the outside are reduced. As a result, the flow flowing backward from the outside into the inner peripheral side space is reduced, and the shielding performance can be further improved.

[0036] (4) The shielding gas ejection device 100 according to the fourth aspect is further provided with a plurality of vanes 18 provided in the middle of the outer shielding gas ejection path 40 and arranged in the circumferential direction of the axis O, and the vanes 18 extend from one side in the circumferential direction to the other side from the upstream side to the downstream side, so that the outer shielding gas is ejected so as to swirl around the axis O.

[0037] According to the above configuration, by simply providing a plurality of vanes 18 in the outer shielding gas ejection path 40, the shielding performance can be improved with a simple structure.

[0038] (5) The shielding gas ejection device 100 according to the fifth aspect is further provided with a chamber 14 provided in the nozzle body 10 into which the outer shielding gas is introduced, and a supply flow path 40a for supplying the outer shielding gas to the chamber 14. The supply flow path 40a extends in a direction with a circumferential component with respect to the axis O, so that the outer shielding gas is ejected so as to swirl around the axis O.

[0039] According to the above configuration, by simply extending the supply flow path 40a in a direction with a circumferential component, the shielding performance can be improved with a simple structure.

[0040] (6) In the shielding gas ejection device 100 according to the sixth aspect, the outer shielding gas ejection path 40 extends from one side in the circumferential direction to the other side from the upstream side to the downstream side, so that the outer shielding gas is ejected so as to swirl around the axis O.

[0041] According to the above configuration, by simply making the extending direction of the outer shielding gas ejection path 40 from one side in the circumferential direction to the other side from the upstream side to the downstream side, the shielding performance can be improved with a simple structure.

[0042] (7) The processing apparatus 200 according to the seventh aspect includes a shielding gas ejection device 100 and a processing unit 90 that performs processing on a workpiece through the inner shielding gas ejection path 20.

[0043] According to the above configuration, processing can be stably performed on the workpiece under higher shielding performance.

Explanation of Reference Numerals

[0044] 100 Shielding gas ejection device 200 Processing apparatus 10 Nozzle body 11 Main part 11a Upper end face 11b Lower end face 12 Reduced diameter part 13 Chamber forming part 13a Side face 14 Chamber 15 Partition plate 18 Vane 19 Guide plate 20 Inner shielding gas ejection path 20a Inner shielding gas supply path 30 Intermediate shielding gas ejection path 40 Outer shielding gas ejection path 40a Outer shielding gas supply path 80 Workpiece 90 Processing unit O Axis

Claims

1. A nozzle body extending along an axis, an inner shield gas ejection passage formed inside the nozzle body and opening on the axis, an outer shield gas ejection passage surrounding the inner shield gas ejection passage from the periphery, an intermediate shield gas ejection passage provided between the inner shield gas ejection passage and the outer shield gas ejection passage, and comprising: A shield gas ejection device in which the flow rate of the intermediate shield gas ejected from the intermediate shield gas ejection passage is lower than the flow rates of the inner shield gas ejected from the inner shield gas ejection passage and the outer shield gas ejected from the outer shield gas ejection passage.

2. The shield gas ejection device according to claim 1, wherein the intermediate shield gas ejection passage and the outer shield gas ejection passage are configured to eject the intermediate shield gas and the outer shield gas in a direction approaching the axis from the upstream side to the downstream side.

3. The shield gas ejection device according to claim 1 or 2, wherein the outer shield gas ejection passage ejects the outer shield gas so as to swirl around the axis.

4. The shield gas ejection device according to claim 3, further comprising a plurality of vanes provided in the middle of the outer shield gas ejection passage and arranged in the circumferential direction of the axis, the vanes extending from one side in the circumferential direction to the other side from the upstream side to the downstream side to eject the outer shield gas so as to swirl around the axis.

5. a chamber provided in the nozzle body into which the outer shield gas is introduced, a supply flow path for supplying the outer shield gas to the chamber, and further comprising: The shield gas ejection device according to claim 3, wherein the supply flow path extends in a direction with a circumferential component with respect to the axis to eject the outer shield gas so as to swirl around the axis.

6. The shield gas ejection device according to claim 3, wherein the outer shield gas ejection passage extends from one side in the circumferential direction to the other side from the upstream side to the downstream side to eject the outer shield gas so as to swirl around the axis.

7. A processing device comprising the shield gas ejection device according to any one of claims 1 to 6, and a processing unit that performs processing on a workpiece through the inner shield gas ejection passage. and comprising.

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