Patent Application
20240091873
The present disclosure relates to a shielding gas ejecting device and a machining device.
For example, in a machining device including an additive manufacturing device or a buildup welding device, it is necessary to prevent oxidation caused by contact of a base material (workpiece) with air. Therefore, these machining devices are provided with a mechanism for supplying the shielding gas to the surface of the base material. A device that ejects shielding gas from the periphery of a laser irradiation unit is known as this type of mechanism. A configuration in which the base material is protected by directly blowing shielding gas from an annular nozzle opening onto the surface of a base material is also known.
Here, when the shielding gas is blown onto the surface of the base material as described above, the shielding gas forms a layer that flows spreading outward on the surface of the base material. On the other hand, a circular vortex is generated by being dragged by the flow of the shielding gas inside this layer. Such circular vortex causes fluctuation in the flow of the shielding gas. As a result, the shielding gas layer is locally or intermittently broken, and there is a possibility of failing to obtain a sufficient shielding effect.
A shielding gas ejecting device according to an example embodiment of the present disclosure includes a nozzle body extending along an axis, an inner shielding gas ejection path provided at a top end of the nozzle body and opened annularly about the axis, an outer shielding gas ejection path surrounding the inner shielding gas ejection path from a periphery, and an intermediate shielding gas ejection path provided between the inner shielding gas ejection path and the outer shielding gas ejection path. A flow velocity of an intermediate shielding gas ejected from the intermediate shielding gas ejection path is lower than a flow velocity of an inner shielding gas ejected from the inner shielding gas ejection path and a flow velocity of an outer shielding gas ejected from the outer shielding gas ejection path.
The above and other elements, features, steps, characteristics and advantages of the present disclosure will become more apparent from the following detailed description of the example embodiments with reference to the attached drawings.
Hereinafter, a machining device 200 and a shielding gas ejecting device 100 according to the first example embodiment of the present disclosure will be described with reference to
As the machining assembly 90, a device appropriately selected from a plurality of types of devices such as a laser irradiation device for performing additive manufacturing and a welding nozzle for performing buildup welding is applied.
The shielding gas ejecting device 100 is used for ejecting the shielding gas to a machining target object (workpiece 80) by the above-described machining assembly 90 to prevent oxidation or surface deterioration from occurring in the object. The shielding gas ejecting device 100 includes a nozzle body 10, an inner shielding gas ejection path 20, an intermediate shielding gas ejection path 30, and an outer shielding gas ejection path 40.
The nozzle body 10 includes a main part 11, a reduced diameter part 12, a chamber forming part 13, and a partition plate 15. The main part 11 has a columnar shape extending along an axis O. The diameter dimension of the main part 11 is constant over the entire region in the axis O direction. The reduced diameter part 12 is integrally provided below the main part 11 (i.e., the side on which the workpiece 80 is positioned). The reduced diameter part 12 has a tapered shape in which the diameter dimension gradually decreases the upper side toward the lower side.
The chamber forming part 13 is provided on the outer peripheral side of the reduced diameter part 12. The chamber forming part 13 has an annular shape protruding radially outward from the outer peripheral surface of the reduced diameter part 12. A space (chamber 14) is formed inside the chamber forming part 13. This chamber 14 is a space for guiding an outer shielding gas described later. The partition plate 15 is provided inside the chamber 14. The partition plate 15 protrudes upward from an upward-facing surface of the inner surface of the chamber 14 and has an annular shape about the axis O. The chamber 14 is segmented by the partition plate 15 into a region on an outer peripheral side and a region on an inner peripheral side. A gap extending in the axis O direction is formed between the upper end surface of the partition plate 15 and the inner wall of the chamber 14.
The inner shielding gas ejection path 20 extends in the axis O direction over the main part 11 and the reduced diameter part 12 described above. The inner shielding gas ejection path 20 is opened on a lower end surface 11b of the reduced diameter part 12. The opening shape of the inner shielding gas ejection path 20 is circular as an example. The inner shielding gas ejection path 20 has a flow path cross-sectional area gradually decreasing the upper side toward the lower side. The inner shielding gas is supplied to this inner shielding gas ejection path 20 through an inner shielding gas supply path 20a formed on the upper end surface of the main part 11. The above-described machining assembly 90 protrudes inside the inner shielding gas ejection path 20. That is, various types of machining by the machining assembly 90 are performed via this inner shielding gas ejection path 20.
The intermediate shielding gas ejection path 30 extends over the main part 11 and the reduced diameter part 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 in the entire region in the circumferential direction about the axis O. An outlet of the intermediate shielding gas ejection path 30 is opened on the lower end surface 11b. This opening has an annular shape about the axis O. In the intermediate shielding gas ejection path 30, a part penetrating the main part 11 extends in the axis O direction, and a part penetrating the reduced diameter part 12 extends in a direction getting closer to the axis O from the upper side toward the lower side. The intermediate shielding gas is supplied to the intermediate shielding gas ejection path 30 from an inlet opening on an upper end surface 11a.
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 in the entire region in the circumferential direction about the axis O. The outer shielding gas ejection path 40 extends in a direction getting closer to the axis O from the upper side toward the lower side. The outlet of the outer shielding gas ejection path 40 is positioned upward relative to the lower end surface 11b. The outer shielding gas guided from the chamber 14 flows through the outer shielding gas ejection path 40. This outer shielding gas is supplied to the chamber 14 through an outer shielding gas supply path 40a formed on a side surface 13a of the chamber forming part 13. The outer shielding gas supply path 40a is provided only at one location in the circumferential direction, for example. Note that the outer shielding gas supply paths 40a can be provided 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 in the entire region in the circumferential direction by colliding with the partition plate 15. This allows the outer shielding gas to be ejected in a uniform flow rate distribution in the circumferential direction.
In the shielding gas ejecting device 100 configured as described above, the flow rate and the pressure are adjusted so that the flow velocity decreases in the order of the inner shielding gas, the outer shielding gas, and the intermediate shielding gas. 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 velocities may be made different as described above by using various valves or the like, or gases having different flow velocities may be supplied from different supply sources.
Next, the operation of the machining device 200 and the shielding gas ejecting device 100 will be described. In operating the machining device 200, first, the shielding gas ejecting device 100 is driven to form a shielding region on the surface of the workpiece 80. Next, the workpiece 80 is subjected to various types of machining by driving the machining assembly 90.
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 spreading outward on the surface of the workpiece 80 (solid arrows in
However, in the above configuration, the 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 entrained flow that causes the circular vortex flows out around along with the flow of the intermediate shielding gas. As a result, the circular vortex is less likely to be formed. This can reduce the possibility that the flow of the shielding gas fluctuates. As a result, it is possible to avoid breakage of the shield due to the shielding gas. Therefore, the machining work can be performed more stably.
The flow velocity of the intermediate shielding gas is smaller than the flow velocity of the outer shielding gas or the flow velocity of the inner shielding gas. Therefore, it is also possible to reduce the possibility that the original flow of the outer shielding gas and the inner shielding gas is inhibited by the intermediate shielding gas. This allows the machining operation to be performed more stably.
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 getting closer to the axis O from the upper side (upstream side) toward the lower side (downstream side). This can form a space more firmly shielded in the region on the workpiece 80 including the axis O by the intermediate shielding gas and the outer shielding gas.
The first example 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 the shielding gas ejecting device 100 is applied to the additive manufacturing device presented as an example of the machining assembly 90 in the first example embodiment, a supply path for supplying powder to become a material for additive manufacturing can be formed between the inner shielding gas ejection path 20 and the intermediate shielding gas ejection path 30.
A porous plate can also be used as the above-described partition plate 15. Also in this case, the outer shielding gas supplied from the outer shielding gas supply path 40a can be diffused in the circumferential direction, and the outer shielding gas can be ejected in a uniform flow rate distribution.
Next, the second example embodiment of the present disclosure will be described with reference to
According to the above configuration, since the outer shielding gas circles about the axis O, the flow direction when the outer shielding gas collides with the workpiece 80 is limited, and the flow field is stabilized. For this reason, the fluctuation amount of the flow of the outer shielding gas from the space on the inner peripheral side toward the outside is reduced. As a result, the flow flowing backward from the outside to the space on the inner peripheral side 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. According to the above configuration, the shielding performance can be improved in a simple structure only by providing the outer shielding gas ejection path 40 with the plurality of vanes 18. This can suppress an increase in cost related to manufacturing and maintenance of the device.
The second example 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 illustrated in
As illustrated in
The shielding gas ejecting device 100 described in each example embodiment is understood as follows, for example.
(1) The shielding gas ejecting device 100 according to a first aspect includes: a nozzle body 10 extending along an axis O; an inner shielding gas ejection path 20 formed inside the nozzle body 10 and opened on the axis O; an outer shielding gas ejection path 40 surrounding the inner shielding gas ejection path 20 from a periphery; and an intermediate shielding gas ejection path 30 provided between the inner shielding gas ejection path 20 and the outer shielding gas ejection path 40, in which a flow velocity of an intermediate shielding gas ejected from the intermediate shielding gas ejection path 30 is lower than a flow velocity of an inner shielding gas ejected from the inner shielding gas ejection path 20 and a flow velocity of an outer shielding gas ejected from the outer shielding gas ejection path 40.
Here, if only the inner shielding gas and the outer shielding gas are blown onto the surface of the target object, these shielding gases form a layer that flows spreading outward on the surface of the target object. On the other hand, a circular vortex is generated by being dragged by the flow of the shielding gas inside this layer. Such circular vortex causes fluctuation in the flow of the shielding gas. However, in the above configuration, the 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 entrained flow that causes the circular vortex diffuses around along with the flow of the intermediate shielding gas. As a result, the circular vortex is less likely to be formed. This can reduce the possibility that the flow of the shielding gas fluctuates.
(2) In the shielding gas ejecting device 100 according to a second aspect, 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 getting closer to the axis O from the upstream side toward the downstream side.
According to the above configuration, it is possible to form a space more firmly shielded in the region including the axis O by the intermediate shielding gas and the outer shielding gas.
(3) In the shielding gas ejecting device 100 according to a third aspect, the outer shielding gas ejection path 40 causes the outer shielding gas to be ejected so as to circle about the axis O.
According to the above configuration, since the outer shielding gas circles about the axis O, the flow direction when the outer shielding gas collides with the target object is limited, and the flow field is stabilized. Therefore, fluctuation of the flow of the outer shielding gas from the space on the inner peripheral side toward the outside is reduced. As a result, the flow flowing backward from the outside to the space on the inner peripheral side is reduced, and the shielding performance can be further improved.
(4) The shielding gas ejecting device 100 according to a fourth aspect further includes a plurality of the vanes 18 provided in the middle of the outer shielding gas ejection path 40 and arrayed in the circumferential direction of the axis O, and the vanes 18 extend from one side to the other side in the circumferential direction from the upstream side toward the downstream side to cause the outer shielding gas to be ejected so as to circle about the axis O.
According to the above configuration, the shielding performance can be improved in a simple structure only by providing the outer shielding gas ejection path 40 with the plurality of vanes 18.
(5) The shielding gas ejecting device 100 according to a fifth aspect further includes the chamber 14 provided in the nozzle body 10 and into which the outer shielding gas is introduced, and a supply flow path 40a through which the outer shielding gas is supplied to the chamber 14, in which the supply flow path 40a extends in a direction having a circumferential component with respect to the axis O to cause the outer shielding gas to be ejected so as to circle about the axis O.
According to the above configuration, the shielding performance can be improved in a simple structure only by extending the supply flow path 40a in the direction having the circumferential component.
(6) In the shielding gas ejecting device 100 according to a sixth aspect, the outer shielding gas ejection path 40 extends from one side to the other side in the circumferential direction from the upstream side toward the downstream side to cause the outer shielding gas to be ejected so as to circle about the axis O.
According to the above configuration, the shielding performance can be improved in a simple structure only by setting the extending direction of the outer shielding gas ejection path 40 to a direction from one side to the other side in the circumferential direction from the upstream side toward the downstream side.
(7) A machining device 200 according to a seventh aspect includes the shielding gas ejecting device 100 and the machining assembly 90 that performs machining on a workpiece via the inner shielding gas ejection path 20.
According to the above configuration, it is possible to stably perform machining on the workpiece with a higher shielding performance.
While example embodiments of the present disclosure have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present disclosure. The scope of the present disclosure, therefore, is to be determined solely by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-013504 | Jan 2021 | JP | national |
This is a U.S. national stage of application No. PCT/JP2022/003360, filed on Jan. 28, 2022, and claiming priority to Japanese Patent Application No. 2021-013504, filed in Japan on Jan. 29, 2021, the entire contents of which are hereby incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2022/003360 | 1/28/2022 | WO |
