JP7339043B2 - LAMINATED MAKING METHOD AND TWIN SCROLL CASING - Google Patents

Description

The present disclosure relates to additive manufacturing methods and twin scroll casings.

In order to form an overhang having a downward surface in the metal lamination direction by three-dimensional additive manufacturing (additive manufacturing) in which metals are laminated to form a product, the overhang must be formed and The support that supports the overhang is also modeled. Supports also have other functions such as preventing deformation of molded parts, improving thermal conductivity, and supporting shapes, and are used in various molding scenes. The supports need to be removed after molding, but in narrow spaces that are inaccessible to workers and tools, it is often difficult to remove the supports with tools such as chisels and hammers. It is possible to remove supports by shot blasting by lowering the build density of the supports to make them weaker, but if the supports are of low strength, the overhangs will deform or break during the build. there is a possibility.

Although it is not used to remove supports, dry ice pellets are sprayed onto dirt and film on the surface of various products, and the small explosion phenomenon when the dry ice pellets sublime pulverizes and removes dirt and film. Techniques for doing so are described in Patent Documents 1 to 4, for example.

Japanese Patent No. 5615844 International Publication No. 2014/104102 Japanese Unexamined Patent Application Publication No. 2007-1015 JP-A-2002-5596

As a result of intensive studies by the present inventors, it has become clear that the support can be pulverized and removed by using a small explosion phenomenon when dry ice pellets sublimate. None of Patent Documents 1 to 4 describes removal of the support.

In view of the circumstances described above, an object of at least one embodiment of the present disclosure is to provide an additive manufacturing method capable of facilitating the removal of supports.

(1) A layered manufacturing method according to at least one embodiment of the present invention,
Laminating metal to form a twin scroll casing including a twin scroll passage separated into two passages by a partition wall and a support located in at least a partial region of the twin scroll passage;
spraying granular dry ice pellets onto the support;
Prepare.

According to the method (1) above, after the twin scroll casing and the support are formed, by injecting granular dry ice pellets onto the support, at least a part of the support is destroyed by a small explosion phenomenon when the dry ice pellets sublimate. Supports can be easier to remove because they are pulverized to remove them.

(2) In some embodiments, in the method of (1) above, in the step of shaping, at least the overhang angle of the twin scroll flow path is 45 degrees or less when the stacking direction is 90 degrees. The support is shaped in the area of

According to the above method (2), after forming the support in at least a region in which the overhang angle is 45 degrees or less when the stacking direction is 90 degrees in the twin scroll flow path, granular drying is applied to the support. When the ice pellets are injected, at least a part of the support is pulverized by a small explosion phenomenon when the dry ice pellet sublimates, and the support is removed. Therefore, the support can be easily removed.

(3) In some embodiments, in the method of (2) above, the forming step includes forming the support at least in a region where the overhang angle is 65 degrees or less in the twin scroll flow path. do.

According to the above method (3), at least in the twin scroll channel, after forming the support in the region where the overhang angle is 65 degrees or less, when granular dry ice pellets are injected into the support, dry ice pellets At least a portion of the support is pulverized by a small explosion phenomenon when sublimating the support, and the support is removed, so that the support can be easily removed.

(4) In some embodiments, in the method of any one of (1) to (3) above, the shaping step includes shaping the support located in the at least partial region and having a void therein. do.

According to the method (4) above, each of the dry ice pellets sprayed into the voids of the support partially penetrates, so that the support is easily pulverized by a small explosion phenomenon when the dry ice pellets sublimate. , can make the support even easier to remove.

(5) In some embodiments, in the method of (4) above, in the step of shaping, the unit structure located in the at least partial region and configured by a frame and having a void inside The support is shaped to include a three-dimensional structure composed of repeating unit structures.

According to the above method (5), by appropriately setting the dimensions of the frame, at least a part of the support is easily pulverized by a small explosion phenomenon when the dry ice pellets are sublimated while ensuring the strength of the support. can do.

(6) In some embodiments, in the method of (5) above, the shaping step includes the shaping step located in the at least partial region, and the frames arranged to form sides of an octahedron. The support is shaped including the three-dimensional structure composed of repeating unit structures.

According to the above method (6), it is possible to prevent the overhang angle of the frame itself during molding, that is, the overhang angle when the stacking direction is 90 degrees, from becoming too small, so that the frame can be easily molded.
Further, according to the method (6), the dry ice pellets are ejected from the holes surrounded by the frame arranged so as to form the sides of the octahedron regardless of which direction of the frame the dry ice pellets are ejected from. becomes easier to partially invade. As a result, even if the dry ice pellets are jetted from any direction of the frame, the support can be easily pulverized by a small explosion phenomenon when the dry ice pellets sublime, so that the support can be easily removed.
Furthermore, since the three-dimensional structure described above is included, strength as a support can be ensured, so deformation of the twin-scroll casing during molding can be effectively suppressed, and the dimensional accuracy of the twin-scroll casing can be improved.

(7) In some embodiments, in the method of (5) or (6), the forming step forms the support including the three-dimensional structure in which the void size is 1.0 mm or more. do.

As a result of intensive studies by the inventors, it has been found that when the size of the void is 1.0 mm or more, the support is easily pulverized by a small explosion phenomenon when the dry ice pellets are sublimated, and the support is easily removed. found.
Therefore, according to the method (7) above, the support can be easily removed.

(8) In some embodiments, in any one of the above methods (1) to (7), the shaping step includes a heat input of 5% or more and 30% or less of the heat input when shaping the partition wall. to shape the support located in the at least one region.

As a result of diligent studies by the inventors, the amount of heat input when molding the support, that is, the magnitude of the energy per irradiation area of the energy beam irradiated during molding of the support, is 5% or more of the heat input when molding the partition wall. It has been found that when the content is 30% or less, the support is easily pulverized by a small explosion phenomenon when the dry ice pellets are sublimated while ensuring the strength of the support.
Therefore, according to the above method (8), the support can be easily removed while ensuring the strength of the support.

(9) In some embodiments, in the method of any one of (1) to (8) above, the shaping step includes stacking metals of nickel alloy, cobalt alloy, or titanium alloy. The support may be shaped.

(10) In some embodiments, in the method of (9), the shaping step may use powder of heat resistant steel or stainless steel to shape the support.

(11) In some embodiments, in the method according to any one of (1) to (10) above, the step of injecting includes: The dry ice pellets are sprayed onto the support located in the at least partial region through a nozzle configured to be accessible from the radially inner side of the casing.

In a rotating machine having a twin-scroll casing, an impeller is arranged in a region radially inside the twin-scroll casing with respect to the twin-scroll passage. Therefore, in the twin-scroll casing, the region communicates with the twin-scroll flow path, and the twin-scroll flow path can be accessed from the radially inner side of the twin-scroll casing.
According to the method (11) above, the dry ice pellets are jetted onto the support located in the at least partial region through the nozzle configured to be accessible from the radially inner side of the twin scroll casing. Since the dry ice pellets can be jetted against the support from a position relatively close to the support, the support can be more easily removed.

(12) In some embodiments, in the method of (11) above, the step of injecting is along an opening of the twin-scroll flow path that is open radially inward in the twin-scroll casing. The dry ice pellets are sprayed onto the support located in the at least one region through the nozzle having a tip.

According to the above method (12), the tip of the nozzle is brought close to the opening to inject dry ice pellets onto the support, thereby injecting dry ice pellets onto the support from a position relatively close to the support. Since it can be done, the support can be made easier to remove.

(13) In some embodiments, in the method according to any one of (1) to (12) above, after the step of injecting, shot blasting is performed on the at least part of the region to and adjusting the roughness of the inner peripheral surface of the.

According to the method (13) above, it is possible to suppress the difference in roughness of the inner peripheral surface between the region where the support is formed and the region where the support is not formed in the twin scroll flow path.

(14) A twin scroll casing according to at least one embodiment of the present invention,
a partition provided between two flow paths of the twin scroll flow path to separate the two flow paths;
a wall portion forming the twin scroll flow path;
with
The wall portion and the partition wall are integrally formed by lamination molding over the entire circumference of the twin-scroll flow path.

According to the configuration (14) above, since it is not necessary to prepare a mold for casting the wall portion and the partition wall, the cost of the mold can be suppressed.

(15) In some embodiments, in the configuration of (14) above, the surface roughness of at least a part of the outer peripheral surface of the twin-scroll casing is The surface roughness is greater than that of a region located on the opposite side of the at least one region across the axis.

For example, when a twin-scroll casing including the wall portion and the partition wall is modeled by additive manufacturing, a support may be formed in a portion having a cavity on the lower side, ie, an overhang region, during additive manufacturing. When the support is formed in at least the partial region of the outer peripheral surface of the twin scroll casing, the support is often formed in the region located on the opposite side of the twin scroll flow path. In this case, the surface roughness of the at least partial region of the outer peripheral surface after the support is removed and the region located on the opposite side of the twin-scroll flow path is reduced by shot blasting, for example. If the treatment is not sufficient, it is conceivable that the surface roughness will be greater than that of the areas where the support was not formed.
However, if the difference between the surface roughness of the area located on the opposite side of the twin-scroll flow path and the surface roughness of the other area of the twin-scroll flow path becomes relatively large, the flow of fluid flowing through the twin-scroll flow path is adversely affected. There is a risk of
With configuration (15) above, the surface roughness of the at least partial region of the outer peripheral surface is greater than the surface roughness of the region located on the opposite side of the twin-scroll flow path. That is, the surface roughness of the region located on the opposite side of the twin scroll flow path is smaller than the surface roughness of the at least part of the outer peripheral surface. Therefore, according to the above configuration (15), compared to the case where the surface roughness of the region located on the opposite side of the twin scroll flow path is equal to or greater than the surface roughness of the at least part of the outer peripheral surface, It is possible to suppress the influence of the surface roughness of the region located on the opposite side of the twin-scroll flow path on the flow of the fluid flowing through the twin-scroll flow path.

According to at least one embodiment of the present invention, it is possible to provide a layered manufacturing method that allows the support to be easily removed.

FIG. 4 is a view showing a turbocharger casing according to some embodiments in a position during additive manufacturing, as described below. FIG. 4 is a diagram schematically showing a cross section of a twin scroll casing among turbocharger casings according to some embodiments. It is a flow chart which shows the processing procedure in the layered manufacturing method concerning some embodiments. FIG. 4 is a schematic diagram for explaining the principle that supports are removed by jetted dry ice pellets according to some embodiments; FIG. 4 is a schematic diagram for explaining an example of a support shaped in a twin-scroll channel; FIG. 10 is a schematic diagram for explaining another example of the support shaped in the twin-scroll channel; 1. It is a figure which shows typically the external appearance of the twin scroll casing by the VII arrow in FIG. FIG. 4 is a perspective view schematically showing an example of a three-dimensional structure of an in-channel support; FIG. 9 is a perspective view of a unit structure of the three-dimensional structure in the embodiment shown in FIG. 8; FIG. 9 is a perspective view of a unit structure of the three-dimensional structure in the embodiment shown in FIG. 8; FIG. 5 is a diagram showing the relationship between the amount of heat input, the size of the gap, and the thickness of the frame when molding the in-channel support. FIG. 5 is a diagram for explaining an attachment nozzle suitable for injecting dry ice pellets onto an in-flow-path support in an injecting process; It is a typical perspective view of an attachment nozzle.

Several embodiments of the present invention will now be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention, and are merely illustrative examples. do not have.
For example, expressions denoting relative or absolute arrangements such as "in a direction", "along a direction", "parallel", "perpendicular", "center", "concentric" or "coaxial" are strictly not only represents such an arrangement, but also represents a state of relative displacement with a tolerance or an angle or distance to the extent that the same function can be obtained.
For example, expressions such as "identical", "equal", and "homogeneous", which express that things are in the same state, not only express the state of being strictly equal, but also have tolerances or differences to the extent that the same function can be obtained. It shall also represent the existing state.
For example, expressions that express shapes such as squares and cylinders do not only represent shapes such as squares and cylinders in a geometrically strict sense, but also include irregularities and chamfers to the extent that the same effect can be obtained. Shapes including parts etc. shall also be represented.
On the other hand, the expressions "comprising", "comprising", "having", "including", or "having" one component are not exclusive expressions excluding the presence of other components.

(Regarding turbocharger 1)
FIG. 1 is a diagram showing a posture of a casing of a turbocharger according to some embodiments during lamination manufacturing as described below. FIG. 2 is a diagram schematically showing a cross section of a twin scroll casing among turbocharger casings according to some embodiments.
Hereinafter, a turbocharger will be described as an example of a rotating machine having a twin scroll casing according to the present disclosure.
A turbocharger 1 according to some embodiments is an exhaust turbocharger for supercharging the intake air of an engine mounted on a vehicle such as an automobile.
The turbocharger 1 includes a turbine wheel 3 and a compressor wheel (not shown) connected with a rotor shaft 2 as a rotation axis, a turbine housing 5 that rotatably accommodates the turbine wheel 3, and a rotor shaft 2 that is rotatably supported. It has the illustrated bearing, a bearing housing 4 that accommodates the bearing, and a not-illustrated compressor housing that rotatably accommodates the compressor wheel.

(Turbine 7)
A turbine 7 according to some embodiments comprises a turbine wheel 3 and a turbine housing 5 . Note that the turbocharger 1 according to some embodiments is a twin scroll turbocharger in which two exhaust gas introducing passages (twin scroll passages) are formed in the turbine housing 5 . The turbine housing 5 is also called a twin scroll casing 5 in the following description.

As will be described in detail later, as shown in FIG. 1 , in the turbocharger 1 according to some embodiments, by three-dimensional additive manufacturing (additive manufacturing) in which metals are layered to form a product, The bearing housing 4 and the twin scroll casing 5 are integrally formed as one member. In addition, in the turbocharger 1 according to some embodiments, the twin scroll casing 5 may be integrally formed as one member separately from the bearing housing 4 .

(Twin scroll casing 5)
The twin-scroll casing 5 according to some embodiments includes a twin-scroll passageway 50 separated into two passageways 53 , 55 by a partition wall 51 . The twin-scroll casing 5 according to some embodiments includes walls 52 that define the twin-scroll flowpath 50 .
In the turbocharger 1 according to some embodiments, an impeller (turbine wheel 3 ) is arranged in a region 5 a radially inner of the twin scroll casing 5 than the twin scroll passage 50 . Therefore, in the twin-scroll casing 5 according to some embodiments, the region 5a and the twin-scroll passage 50 communicate with each other. Specifically, an opening 57 is formed in the twin scroll casing 5 according to some embodiments. The opening 57 is an opening of the twin scroll passage 50 and opens radially inward about the axis AX of the rotor shaft 2 .

In the following description, the radial direction centered on the axis AX of the rotor shaft 2 is simply referred to as the radial direction, the radially inner side centered on the axis AX is simply referred to as the radially inner side, and the radially outer side about the axis AX is simply referred to as the radially inner side. is also simply referred to as the radially outer side. In addition, in the following description, the circumferential direction around the axis AX of the rotor shaft 2 is simply referred to as the circumferential direction.

In the twin scroll casing 5 according to some embodiments, the partition wall 51 is formed to protrude radially inward from the inner peripheral surface of the twin scroll flow path 50 . A radially inner tip portion 51 a of the partition wall 51 is located near the opening portion 57 .

In the turbine 7 according to some embodiments, the exhaust gas that has flowed into the twin-scroll casing 5 from, for example, the connecting portion 13 connected to the exhaust (not shown) of the engine (not shown) flows through the twin-scroll flow path 50 to the turbine. act on wheel 3; Exhaust gas that has acted on the turbine wheel 3 is discharged to the outside of the twin scroll casing 5 from an exhaust gas outlet 15 that opens in the axial direction of the rotor shaft 2 .

(About the manufacturing method of the twin scroll casing 5)
A method of manufacturing the above-described twin scroll casing 5 will be described below. FIG. 3 is a flow chart showing a processing procedure in a layered manufacturing method according to some embodiments.
A layered manufacturing method according to some embodiments includes a modeling step S10, an injection step S20, and a roughness adjusting step S30.

(Overview of modeling process S10)
In the forming step S10 according to some embodiments, at least the twin scroll casing 5 and the twin scroll flow path 50 including the twin scroll flow path 50 separated into the two flow paths 53 and 55 by the partition wall 51 are laminated by metal. This is a process of shaping the support 100 located in a partial area. In the modeling step S10 according to some embodiments, powder bed fusion (PBF), directed energy deposition (DED), binder jetting (BJ), selective The twin scroll casing 5 and the support 100 are formed by any one of methods such as selective laser manufacturing (SLM) and laser metal deposition (LMD).

In the modeling step S10 according to some embodiments, at least the twin scroll casing 5 is integrally modeled as one member by the layered modeling method according to any of the methods described above. That is, the twin scroll casing 5 according to some embodiments includes partition walls 51 and wall portions 52 . The wall portion 52 and the partition wall 51 according to some embodiments are integrally formed by lamination molding over the entire circumference of the twin scroll flow path 50 .
As a result, there is no need to create a casting mold for the wall portion 52 and the partition wall 51, so the cost of the mold can be suppressed.
For example, even if it is necessary to change the shape of the two flow paths 53 and 55 of the twin scroll flow path 50, there is no need to create a mold for casting, so the preparation period and cost for manufacturing can be suppressed. The additive manufacturing method according to some embodiments is particularly suitable for manufacturing prototypes of twin scroll flow channels 50 that are manufactured in small numbers.

In the modeling step S10 according to some embodiments, in the injection step S20, the at least one The support 100 is shaped so that the support 100 located in the area of the part can hold the dry ice pellet.
Details of the modeling step S10 will be described later.

(Overview of injection step S20)
The injection step S20 according to some embodiments is a step of injecting granular dry ice pellets onto the support 100 . In the injection step S20 according to some embodiments, the support 100 is pulverized and removed by injecting granular dry ice pellets onto the support 100 .

FIG. 4 is a schematic diagram for explaining the principle that the support 100 according to some embodiments is removed by jetted dry ice pellets. In some embodiments, the support 100 located in the at least partial area has a plurality of holes (voids 120) through which, for example, each of the ejected dry ice pellets can at least partially enter, as described below. It is preferably formed as a porous body having

As shown in FIG. 4 , the dry ice pellets 30 jetted against the support 100 at least partially penetrate the voids 120 of the support 100 . When the dry ice pellets 30 sublimate in this state, a small explosion occurs in which the volume of gaseous carbon dioxide expands to about 800 times the volume of the dry ice pellets 30 . The impact of this small explosion destroys the frame 111 that defines the gap 120 . The support 100 is pulverized by this phenomenon occurring in the plurality of gaps 120 . Depending on the strength of the frame 111 , the frame 111 may be destroyed by the impact when the jetted dry ice pellets 30 collide with the frame 111 .
In addition, the detail of injection process S20 is demonstrated later.

(Overview of Roughness Adjustment Step S30)
In the roughness adjusting step S30 according to some embodiments, after the jetting step S20 is completed, the region where the support 100 was formed is subjected to, for example, shot blasting to adjust the roughness of the inner peripheral surface 50a of the twin scroll flow path 50. is a step of adjusting the
For example, when the difference between the surface roughness of the region where the support 100 was formed in the twin-scroll flow path 50 and the surface roughness of other regions of the twin-scroll flow path 50 becomes relatively large, the flow of the fluid flowing through the twin-scroll flow path 50 increases. It may adversely affect the flow.
By performing the roughness adjustment step S30 according to some embodiments, the inner peripheral surface 50a in the region where the support 100 was formed and the region where the support 100 was not formed in the twin scroll flow path 50 A difference in roughness can be suppressed. As a result, it is possible to suppress the above-described adverse effects and reduce the efficiency of the turbine 7 .

In addition, in the roughness adjusting step S30 according to some embodiments, shot blasting is mainly performed on the inner peripheral surface 50a of the twin scroll flow path 50 in the region where the support 100 was formed. Shot blasting may be performed on a region other than the inner peripheral surface 50a of the twin scroll flow path 50 in the region where 100 was formed. For example, a decrease in efficiency of the turbine 7 can be suppressed by shot blasting the region of the inner peripheral surface of the exhaust gas outlet 15 where the support 100 was formed.

Since the layered manufacturing method according to some of the embodiments described above includes the modeling step S10 and the injection step S20, the granular dry ice pellets 30 are injected to the support 100 after forming the twin scroll casing 5 and the support 100. Accordingly, at least a portion of the support 100 is pulverized by a small explosion phenomenon when the dry ice pellets 30 are sublimated, and the support 100 is removed, so that the support 100 can be easily removed.

(About Support 100)
In order to form an overhang having a downward surface in the metal lamination direction by three-dimensional additive manufacturing (additive manufacturing) in which metals are laminated to form a product, the overhang must be formed and A support 100 that supports the overhang is also shaped. The support 100 also has functions of preventing deformation of parts to be molded, improving thermal conductivity, and supporting shapes, and is used in various molding scenes.
In some embodiments, each overhang part such as an overhang part on the outer peripheral surface of the twin scroll casing 5, an overhang part on the inner peripheral surface of the exhaust gas outlet 15, an overhang part in the twin scroll flow path 50, etc. Along with molding, the support 100 is also molded.

In some embodiments, supports 100 are molded into the overhangs of the twin-scroll passages 50 to integrally mold the twin-scroll casing 5 around its entire circumference.
FIG. 5 is a schematic diagram for explaining an example of the support 100 shaped in the twin scroll channel 50. As shown in FIG. Note that FIG. 5 is a schematic diagram showing an example in which the support 100 is formed in a region where the overhang angle θo, which will be described later, of the overhang portion 60 is 45 degrees or less.
FIG. 6 is a schematic diagram for explaining another example of the support 100 shaped in the twin-scroll channel 50. As shown in FIG. FIG. 6 is a schematic diagram showing an example in which the support 100 is formed in a region where the overhang angle θo of the overhang portion 60 is 65 degrees or less.
FIG. 7 is a diagram schematically showing the external appearance of the twin scroll casing 5 as viewed from arrow VII in FIG. is.

In some embodiments, the attitude of the turbine housing 5 during additive manufacturing is determined in consideration of the ease of forming an overhang, the ease of removing the support 100 after manufacturing, and the like. In some embodiments, as shown in FIG. 1 , the attitude of the turbine housing 5 during additive manufacturing is such that the height position of the axis AX is higher on the downstream side of the exhaust gas outlet 15 than on the upstream side. Slanted posture.

In the description of each figure, the directions are defined as follows based on the posture of the turbine housing 5 during lamination manufacturing shown in FIG. That is, the vertical direction during lamination molding is taken as the z-axis, and the vertical upward direction is taken as the positive direction of the z-axis direction. Among the horizontal directions, the x-axis is the direction that overlaps the extending direction of the axis AX when the turbine housing 5 during additive manufacturing is viewed from above, and the direction from the downstream side to the upstream side of the exhaust gas outlet 15 is the x-axis. Let it be the positive direction of the x-axis direction. Of the horizontal directions, the direction orthogonal to the x-axis is taken as the y-axis, and the direction from the axis AX toward the connection portion 13 is taken as the positive direction of the y-axis direction.
The angle formed by the x-axis and the axis AX is defined as the inclination angle θax of the axis AX. An overhang angle θo is defined as an angle between the extending direction of the downward surface forming the overhang portion and the x-axis. That is, the overhang angle on the horizontal plane is 0 degrees and the overhang angle on the vertical plane is 90 degrees.
In the modeling step S10, the product is modeled by sequentially stacking metals vertically upward. Therefore, in the modeling step S10, the metal lamination direction is vertically upward, that is, the positive direction of the z-axis direction.

In some embodiments, as shown in FIG. 5, in the molding step S10, at least the overhang angle θo of the twin scroll flow path 50 when the stacking direction is 90 degrees is 0 degrees or more and 45 degrees or less. The support 100 is shaped in the region 61 which becomes .
As a result, after forming the support 100 in the region 61 in which the overhang angle is at least 0 degree or more and 45 degrees or less when the stacking direction is 90 degrees in the twin scroll flow path 50, granular drying is applied to the support 100. When the ice pellets 30 are injected, at least a part of the support 100 is pulverized by a small explosion phenomenon when the dry ice pellets 30 sublime, and the support 100 is removed, so the support 100 can be easily removed.
Further, by forming the support 100 in a region of the twin scroll flow path 50 where the overhang angle θo is 0 degrees or more and 45 degrees or less, the dimensional accuracy of the region can be ensured.

In some embodiments, as shown in FIG. 6, in the forming step S10, the support 100 is formed at least in the region 62 where the overhang angle θo is 0 degrees or more and 65 degrees or less in the twin scroll flow path 50. may
As a result, after forming the support 100 in the region 62 where the overhang angle θo is at least 0 degree or more and 65 degrees or less in the twin scroll flow path 50, when the granular dry ice pellets 30 are injected onto the support 100, the dry At least a part of the support 100 is pulverized by a small explosion phenomenon when the ice pellet 30 sublimates, and the support 100 is removed, so that the support 100 can be easily removed.

In addition, by molding the support 100 in the region where the overhang angle θo is 0 degrees or more and 65 degrees or less in the twin scroll flow path 50, the dimensional accuracy of the region where the overhang angle is more than 45 degrees and 65 degrees or less can be further ensured.

In addition, in some embodiments, the forming range (angle range θc) in the circumferential direction of the support 100 formed in the twin scroll flow path 50 is centered on the uppermost position in the vertical direction, as shown in FIG. , for example, 60 degrees (θc=60 degrees) along the circumferential direction.

(See support 100 for details)
The support 100 according to some embodiments not only supports the overhang portion 60, but also has functions such as deformation prevention due to heat shrinkage during lamination manufacturing. Therefore, the support 100 requires a certain degree of strength. On the other hand, the support 100 according to some embodiments is required to be easily destroyed by the impact of a small explosion of the dry ice pellets 30, as described above.
Particularly in the twin scroll casing 5 according to some embodiments, in order to remove the support 100 shaped into the twin scroll channel 50, dry ice is poured inside the two channels 53, 55 through the relatively narrow opening 57. Pellets 30 must be supplied. For example, compared to a region that is relatively easy to access from the outside of the twin scroll casing 5, such as an overhang portion on the outer peripheral surface of the twin scroll casing 5 and an overhang portion on the inner peripheral surface of the exhaust gas outlet 15, the twin scroll flow The interior of channel 50 is a relatively inaccessible area. Therefore, it is desired that the support 100 formed inside the twin-scroll flow path 50 is easy to remove after lamination manufacturing while ensuring strength as a support.

Therefore, the support 100 according to some embodiments is provided with the following configuration to ensure the strength of the support 100 and facilitate removal after lamination manufacturing. In the following description, the support 100 shaped in the twin-scroll flow path 50 is mainly described, but the support 100 shaped in areas other than the twin-scroll flow path 50 is also applicable.
In the following description, the support 100 formed in the twin-scroll flow path 50 is also particularly referred to as an intra-flow path support 110 .
Further, in the following description, the region 61 or the region 62 that is at least a part of the twin-scroll flow path is also called a forming region 63 .

Specifically, in some embodiments, the intrachannel support 110 has voids 120 therein. That is, in some embodiments, in the forming step S10, at least the intra-channel support 110 located in the formation region 63 and having the void 120 therein is formed.
As a result, each of the dry ice pellets 30 injected into the gap 120 of the in-channel support 110 partially enters, and the in-channel support 110 is pulverized by a small explosion phenomenon when the dry ice pellets 30 sublimate. This makes it easier to remove the in-channel support 110 .

Various configurations can be applied to the detailed configuration of the in-channel support 110 formed to have the void 120 inside. For example, in some embodiments, the intra-channel support 110 may include a three-dimensional structure composed of repetitions of unit structures composed of frames 111 and having voids 120 therein. good.
FIG. 8 is a perspective view schematically showing an example of the three-dimensional structure. FIG. 8 illustrates a part of the in-channel support 110 .
The in-flow-path support 110 shown in FIG. 8 includes a three-dimensional structure 130 formed by repeating unit structures 131 formed by frames 111 and having voids 120 therein.
That is, in some embodiments, in the modeling step S10, at least the unit structure 131 located in the forming region 63 and configured by the frame 111 and having the void 120 inside is repeated. The intrachannel support 110 including the original structure 130 is shaped.
As a result, by appropriately setting the dimensions of the frame 111, at least a part of the in-channel support 110 is pulverized by a small explosion phenomenon when the dry ice pellets 30 sublimate while ensuring the strength of the in-channel support 110. can be made easier.

The amount of heat input when molding the support 100, that is, the magnitude of the energy per irradiation area of the energy beam irradiated when molding the support 100 is made smaller than the amount of heat input when molding the twin scroll casing 5. It is difficult to secure strength as a support only by forming the 100 into a porous shape.
On the other hand, in some embodiments, by having the three-dimensional structure 130 configured by repeating the unit structures 131, the strength of the in-channel support 110 can be relatively increased. Strength can be secured.

Further, according to some embodiments, it is possible to control the removability of the in-channel support 110 by the dry ice pellets 30 by changing the dimension of the void 120 of the unit structure.

(Regarding the three-dimensional structure 130)
The three-dimensional structure 130 shown in FIG. 8 will be further described.
In a three-dimensional structure 130 according to an embodiment shown in FIG. 8, a frame 111 includes shaft portions 113 extending in different directions, and connecting portions 114 in which ends of different shaft portions 113 are connected to each other. there is In one embodiment shown in FIG. 8, shaft 113 includes, for example, four shafts 113a-113d each extending in a different direction. That is, in the three-dimensional structure 130 according to one embodiment shown in FIG. 8, the frame 111 is a three-dimensional network frame.

For example, like the in-channel support 110 shown in FIG. 8, the in-channel support 110 includes at least a first shaft-shaped member that is a plurality of first shaft portions 113 extending in the first extending direction; A second shaft-like member, which is a plurality of second shaft portions 113 extending in a second extending direction that intersects with the first extending direction, may also be included. At least one of the plurality of first shaft portions 113 and at least one of the plurality of second shaft portions 113 may be connected to each other by a connection portion 114 .

FIG. 9 is a perspective view of a unit feature 131 of the three-dimensional structure 130 in one embodiment shown in FIG. In one embodiment shown in FIG. 8, the unit structure 131 of the three-dimensional structure 130 has a unit cell 140 having a shape in which the bottom surfaces of two square pyramids 141A and 141B are overlapped as shown in FIG. In each of the square pyramids 141A and 141B, the shaft portion 113 is arranged at a position corresponding to the line segment connecting the vertex 143 and the corner 145 of the bottom surface.
That is, in one embodiment shown in FIG. 8, frames 111 are arranged to form the sides of an octahedron.
In addition, in the three-dimensional structure 130 in one embodiment shown in FIG. 8, the unit cell 140 has a shape as shown in FIG. 9 when the bottom surfaces of the two quadrangular pyramids 141A and 141B are overlapped. In addition, in the three-dimensional structure 130 in one embodiment shown in FIG. 8, the unit cell 140 has a shape as shown in FIG. 10 when the tops of the two quadrangular pyramids 141A and 141B are overlapped. That is, FIG. 10 is a perspective view of a unit feature 131 of the three-dimensional structure 130 in one embodiment shown in FIG.
In the case of the in-channel support 110 having the unit lattice 140 as shown in FIGS. Formation is facilitated even in the layered manufacturing methods such as the PBF method, the DED method, the BJ method, the SLM method, the LMD method, and the like.

That is, in some embodiments, in the modeling step S10, the three-dimensional structure 130 is formed by repeating unit structures 131 positioned at least in the formation region 63 and arranged so that the frames 111 form the sides of the octahedron. to shape an in-channel support 110 comprising:
As a result, it is possible to prevent the overhang angle θo of the frame 111 itself from becoming too small during layered manufacturing, so that the frame 111 can be easily manufactured.
Also, according to some embodiments, the dry ice pellets 30 are ejected from any direction of the frame 111 and the dry ice is ejected from the holes 121 surrounded by the frame 111 arranged to form the sides of the octahedron. Each of the pellets 30 becomes easier to partially penetrate. As a result, even if the dry ice pellets 30 are ejected from any direction of the frame 111, the small explosion phenomenon when the dry ice pellets 30 sublimate easily crushes the in-channel support 110. can be easily removed.
Furthermore, since the three-dimensional structure 130 described above is included, the strength as a support can be ensured, so deformation of the twin scroll casing 5 during lamination molding can be effectively suppressed, and the dimensional accuracy of the twin scroll casing 5 can be improved.

As a result of intensive studies by the inventors, it was found that among the twin scroll casings 5 according to some embodiments, the partition walls 51 in particular tend to be deformed due to heat shrinkage during lamination molding. .
In this respect, according to some embodiments, for example, as shown in FIGS. Deformation can be effectively suppressed.

(Regarding the dimensions of the gap 120)
Further, as a result of extensive studies by the inventors, it was found that if the size of the gap 120 is 1.0 mm or more, the in-channel support 110 is likely to be pulverized by a small explosion phenomenon when the dry ice pellets 30 sublimate. It has been found that the in-way support 110 is easier to remove.
Therefore, in some embodiments, in the modeling step S10, it is preferable to model the intra-channel support 110 including the three-dimensional structure 130 in which the size of the void 120 is 1.0 mm or more.
This makes it easier to remove the in-channel support 110 .

(Regarding the amount of heat input when molding the in-channel support 110)
Further, as a result of diligent studies by the inventors, if the amount of heat input when forming the in-flow-path support 110 is 5% or more and 30% or less of the amount of heat input when forming the partition wall 51, then the in-flow-path support It was found that the in-channel support 110 is easily pulverized by a small explosion phenomenon when the dry ice pellets 30 are sublimated while ensuring the strength of the support 110 .
Therefore, in some embodiments, in the forming step S10, at least the in-flow-path support 110 located in the forming region 63 may be formed with a heat input of 5% or more and 30% or less of the heat input when forming the partition wall 51. .
As a result, the in-channel support 110 can be easily removed while ensuring the strength of the support.

Specifically, as a material for forming the twin scroll casing 5, nickel alloy powder such as heat-resistant steel or stainless steel containing at least 5% by mass or more of each of nickel, chromium, molybdenum, and iron can be used. can. When the above materials are used, the strength of the in-channel support 110 can be ensured by setting the heat input to the above conditions by adjusting the output of the energy beam during lamination molding, the scanning speed of the energy beam, and the like. However, it has been found that the in-channel support 110 is easily pulverized by a small explosion phenomenon when the dry ice pellets 30 are sublimated.

When the above material is used, if the amount of heat input for molding the in-flow-path support 110 is set to be less than 5% of the heat input for molding the partition wall 51, the molding of the in-flow-path support 110 is difficult. Even if the in-flow-path support 110 can be molded, problems such as molding above the in-flow-path support 110 and deformation of the product area are likely to occur.
Further, when the above material is used, if the amount of heat input when forming the in-channel support 110 exceeds 30% of the amount of heat input when forming the partition wall 51, the strength of the in-channel support 110 decreases. It becomes larger than necessary, and the removability after lamination manufacturing is lowered.

In addition to the materials described above, the following materials can be used as materials for forming the twin scroll casing 5 . That is, as a material for shaping the twin scroll casing 5, for example, a cobalt alloy, a titanium alloy, or the like may be used.

Further, as a result of the inventors' intensive study, it was found that the amount of heat input when molding the in-channel support 110, the size of the gap 120, and the thickness of the frame 111 have the following relationship. . FIG. 11 is a diagram showing the relationship between the amount of heat input when molding the in-channel support 110, the size of the gap 120, and the thickness of the frame 111. As shown in FIG.
As shown in FIG. 11, the smaller the size of the space 120 (the narrower the distance between the frames 111), the smaller the amount of heat input to form the in-flow-path support 110. As shown in FIG. Further, as shown in FIG. 11, the in-flow-path support 110 can be formed with a smaller amount of heat input as the thickness of the frame 111 is increased.

A region 201 surrounded by a dashed line in FIG. 11 represents a range in which the in-channel support 110 can be removed by jetting the dry ice pellets 30 . Further, in FIG. 11, a non-hatched area 205 represents a range in which the in-flow-path support 110 cannot be formed. Here, the range in which the in-channel support 110 cannot be formed means the range in which the frame 111 cannot be formed, or the range in which even if the frame 111 can be formed, the strength required for the in-channel support 110 cannot be obtained. .

Therefore, the region 203 , which is a range in which the in-flow-path support 110 can be molded and in which the in-flow-path support 110 can be removed by jetting the dry ice pellets 30 , satisfies the conditions suitable as the molding conditions of the in-flow-path support 110 . area. Note that in FIG. 11, the region 203 is indicated by diagonal hatching.

(Regarding attachment nozzle 80)
FIG. 12 is a diagram for explaining the attachment nozzle 80 suitable for jetting the dry ice pellets 30 onto the in-flow-path support 110 in the jetting step S20. FIG. 13 is a perspective view schematically showing an attachment nozzle 80 according to one embodiment.
As shown in FIG. 12 , in the injection step S20 according to some embodiments, the twin-scroll flow path 50 is configured to be accessible from the outside of the twin-scroll casing 5 from the radially inner side of the twin-scroll casing 5 . The dry ice pellets 30 may be jetted through the attachment nozzle 80 to at least the in-channel support 110 located in the formation region 63 . The attachment nozzle 80 according to one embodiment is an attachment nozzle that can be attached to the tip of the dry ice blast nozzle 83 .

In the twin-scroll casing 5 according to some embodiments, the area 5a and the twin-scroll flow path 50 communicate with each other as described above, so that the twin-scroll flow path 50 can be accessed from the radially inner side of the twin-scroll casing 5. is.
Therefore, by injecting the dry ice pellets 30 to the in-channel support 110 located at least in the formation region 63 through the attachment nozzle 80 configured to be accessible from the radially inner side of the twin scroll casing 5, Since the dry ice pellets 30 can be jetted onto the in-channel support 110 from a position relatively close to the support 110, the in-channel support 110 can be removed more easily.

Moreover, as shown in FIGS. 12 and 13 , in the attachment nozzle 80 according to one embodiment, the nozzle tip portion 81 is formed along the opening 57 of the twin scroll flow path 50 . Specifically, the attachment nozzle 80 according to one embodiment is such that the nozzle tip 81 is twin-scrolled when brought closer to the opening 57 of the twin-scroll flow path 50 such that the nozzle tip 81 is closer to the opening 57 of the twin-scroll flow path 50 . It has a shape in which a portion that interferes with the casing 5 is cut out.
In the injection step S20 according to some embodiments, as shown in FIG. It is preferable to inject dry ice pellets 30 onto the in-path support 110 .
As a result, the nozzle tip 81 of the attachment nozzle 80 is brought close to the opening 57 and the dry ice pellets 30 are sprayed onto the in-flow support 110 , so that the in-flow support 110 can be ejected from a position relatively close to the in-flow support 110 . Since the dry ice pellets 30 can be jetted against the support 110, the in-channel support 110 can be removed more easily.

The twin scroll casing 5 manufactured by the layered manufacturing method according to some of the embodiments described above may have the following forms.
That is, in the twin-scroll casing 5 according to some embodiments, the surface roughness of at least a part of the outer peripheral surface 5b of the twin-scroll casing 5 is the axial line of the twin-scroll casing 5 in the twin-scroll passage 50, That is, it is larger than the surface roughness of the region located on the opposite side of at least the partial region with respect to the axis AX.

As described above, when the twin scroll casing 5 including the wall portion 52 and the partition wall 51 is modeled by layered manufacturing, the support 100 may be formed in the portion having a cavity on the lower side, that is, the overhang portion 60 during layered manufacturing. . When the support 100 is formed in at least the partial area of the outer peripheral surface 5b of the twin scroll casing 5, the support 100 is also formed in the area located on the opposite side of the twin scroll flow path 50, that is, the formation area 63. often In this case, the surface roughness of the at least part of the outer peripheral surface 5b after the support 100 is removed and the forming region 63 in the twin scroll flow path 50 is reduced by sandblasting, shotblasting, etc., for example. If the treatment is not sufficient, it is conceivable that the surface roughness becomes rougher than the area where the support 100 is not formed.
However, if the difference between the surface roughness of the forming region 63 in the twin-scroll channel 50 and the surface roughness of other regions in the twin-scroll channel 50 becomes relatively large, the flow of fluid flowing through the twin-scroll channel 50 is adversely affected. There is a risk.
Therefore, as described above, the formation region 63 is desirably subjected to shot blasting.

The present invention is not limited to the above-described embodiments, and includes modifications of the above-described embodiments and modes in which these modes are combined as appropriate.
In addition, in the layered manufacturing method according to some embodiments, the case of irradiating a light beam as an energy beam is shown, but the idea of the present invention is the same even when using other forms of energy beams such as an electron beam. applicable to

1 turbocharger 5 twin scroll casing (turbine housing)
30 dry ice pellet 50 twin scroll channel 60 overhang 63 formation region 51 partition wall 57 opening 80 attachment nozzle 81 tip 100 support 110 channel support 130 three-dimensional structure 131 unit structure 140 unit grid

Claims (14)

Laminating metal to form a twin scroll casing including a twin scroll passage separated into two passages by a partition wall and a support located in at least a partial region of the twin scroll passage;
removing the support by blasting the support with granular dry ice pellets to pulverize at least a portion of the support ;
An additive manufacturing method comprising: 2. The support according to claim 1, wherein the forming step forms the support in at least a region of the twin-scroll flow path in which an overhang angle is 0 degrees or more and 45 degrees or less when the stacking direction is 90 degrees. Additive manufacturing method. 2. The support according to claim 1 , wherein the forming step forms the support in at least a region of the twin scroll channel where the overhang angle is 0 degrees or more and 65 degrees or less when the stacking direction is 90 degrees. Additive manufacturing method. The layered manufacturing method according to any one of claims 1 to 3, wherein the forming step forms the support located in the at least partial region and having a void inside. The forming step forms the support including a three-dimensional structure located in the at least partial region and composed of a unit structure composed of a frame and composed of repetition of the unit structure having a void inside. The layered manufacturing method according to claim 4. The forming step forms the support including the three-dimensional structure, which is located in the at least part of the region and is composed of repetitions of the unit structures arranged so that the frame forms the sides of an octahedron. The layered manufacturing method according to claim 5. 7. The layered manufacturing method according to claim 5, wherein the forming step forms the support including the three-dimensional structure in which the size of the void is 1.0 mm or more. 8. The forming step forms the support located in the at least one region with a heat input of 5% or more and 30% or less of the heat input when forming the partition wall. Laminate manufacturing method according to. The layered manufacturing method according to any one of claims 1 to 8, wherein the forming step forms the support by laminating any metal selected from a nickel alloy, a cobalt alloy, and a titanium alloy. 10. The additive manufacturing method of claim 9, wherein the shaping step uses powder of heat-resistant steel or stainless steel to shape the support. In the step of removing the support , from the outside of the twin-scroll casing, the twin-scroll flow path is accessible from the inside of the twin-scroll casing in the radial direction through a nozzle configured to allow access to the at least part of the region. 11. The layered manufacturing method according to any one of claims 1 to 10, wherein the dry ice pellets are jetted onto the support located at . In the step of removing the support , the at least part of the 12. The additive manufacturing method according to claim 11, wherein the dry ice pellets are sprayed onto the support located in the region of . Laminating metal to form a twin scroll casing including a twin scroll passage separated into two passages by a partition wall and a support located in at least a partial region of the twin scroll passage;
spraying granular dry ice pellets onto the support;
a step of adjusting the roughness of the inner peripheral surface of the twin-scroll flow path by shot blasting the at least part of the region after the jetting step is completed;
An additive manufacturing method comprising: a partition provided between two flow paths of the twin scroll flow path to separate the two flow paths;
a wall portion forming the twin scroll flow path;
with
The wall portion and the partition wall are integrally formed by lamination molding over the entire circumference of the twin scroll flow path,
The surface roughness of at least a partial region of the outer peripheral surface of the twin-scroll casing is the surface roughness of a region of the twin-scroll passage located opposite to the at least partial region across the axis of the twin-scroll casing. Greater than surface roughness
Twin scroll casing.

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