JP7640420B2 - FORMED ARTICLE AND METHOD FOR MANUFACTURING FORMED ARTICLE - Google Patents

Description

The present invention relates to a molded object and a method for manufacturing a molded object.

In recent years, there has been an increasing need for 3D printers as a means of production, and research and development is being conducted in the aircraft industry, etc., with a view to practical application of 3D printers to metal materials in particular. 3D printers that use metal materials use a heat source such as a laser or arc to melt metal powder or metal wire, and then layer the molten metal to create a model.

For example, one technique for manufacturing a rotor with blades is to form blades by laminating weld beads around a central shaft (see, for example, Patent Document 1).

JP 2019-155463 A

As an example of further increasing functionality, the above-mentioned molding method can be used to mold a rotating body with cooling function by forming cooling channels inside, but a rotating body with cooling channels requires a balance between mechanical strength and a moldable structure.

For example, in a rotating body having an internal cooling channel, as shown in FIG. 9, the stress concentration coefficient of the cooling channel 1 varies depending on the R-shape of the corners and the ratio of height h to width w when viewed in a cross section parallel to the expected load direction F. For this reason, when forming a rotating body having a cooling channel 1, it is preferable to design it so that the stress concentration coefficient is low, assuming that the main stress will occur in the axial direction from the standpoint of fatigue strength, etc. However, simply increasing the width w or increasing the R-shape of the corners will increase the number of beads in the overhanging parts when stacking beads to form the cooling channel 1, and detailed adjustments to the forming conditions will be required to form the R-shape.

The present invention aims to provide a molded object and a method for manufacturing a molded object that consists of a rotating body with a flow path and in which stress concentration is suppressed.

The present invention comprises the following configurations.
(1) A structure comprising a rotor having a plurality of wing portions formed from a welded metal around a shaft body made of a base metal, a hollow flow passage provided therein, and rotated around the axis of the shaft body,
The flow path is
A plurality of blade flow passages are provided within the blade portion and extend parallel to the blade portion;
A connecting flow passage extending in a direction intersecting the wing portion at an end of the wing portion;
having
The connecting flow passages are alternately connected to the adjacent wing flow passages, and the paths of the flow passages are turned back at the ends of the wing portions.
A sculpture.
(2) A method for producing a shaped object according to (1) above, comprising the steps of:
A wing portion forming process includes forming the wing portion by laminating a weld bead formed by melting and solidifying a filler material on an outer periphery of the shaft while rotating the shaft,
In the wing portion forming step, a flow passage forming step is performed in which the weld bead is extended in parallel along the path of the wing portion flow passage to be continuous with the portion along the connecting flow passage and laminated to form the flow passage.
A method for manufacturing a sculpture.

The present invention provides a molded object that consists of a rotating body with a flow path and in which stress concentration is suppressed.

FIG. 2 is a perspective view of a shaped object according to the present invention. FIG. 2 is a schematic diagram showing a cooling channel in a shaped object of the present invention. FIG. 2 is a schematic cross-sectional view of a blade illustrating the arrangement of cooling channels in the blade. FIG. 4 is a cross-sectional view of a blade flow passage illustrating the cross-sectional shape of a cooling flow passage. FIG. 1 is a schematic diagram illustrating the configuration of a manufacturing system for manufacturing a shaped object. 13A and 13B are side views of a partly molded object illustrating how a blade flow path is formed in the blade molding process. 11A and 11B are cross-sectional views of a portion of a blade in the process of being shaped, illustrating how a blade flow passage is formed in the blade shaping process. 8A and 8B are diagrams illustrating the wing flow passage in the molded object of this example, in which (A) is a schematic diagram of the wing flow passage, (B) is a cross-sectional view taken along line VIIIB-VIIIB in (A), and (C) is a cross-sectional view taken along line VIIIC-VIIIC in (A). FIG. 4 is a cross-sectional view showing a schematic view of a cooling flow passage to which a load is applied.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
Fig. 1 is a perspective view of a shaped object W of the present invention. Fig. 2 is a schematic diagram showing a cooling flow passage 61 in the shaped object W of the present invention. Fig. 3 is a schematic cross-sectional view of a blade 55 illustrating the arrangement of the cooling flow passage 61 in the blade 55.

As shown in FIG. 1, the object W has a shaft body 51 and a molded portion 53 molded on the outer periphery of the shaft body 51, and a blade (wing portion) 55 is formed on the molded portion 53.

The shaft body 51 is, for example, a round bar with a circular cross section, such as a steel bar. The blades 55 of the shaping portion 53 provided on the outer periphery of this shaft body 51 are formed so that the portion protruding toward the outer periphery is twisted in a spiral shape in the axial direction. The shaping portion 53 having these blades 55 is shaped by forming and layering a weld bead around the shaft body 51. The surface of the shaping portion 53 shaped by the weld bead is then cut to form the target shape.

As shown in Figures 2 and 3, the object W has a cooling flow path 61 inside. This cooling flow path 61 is a flow path through which a cooling medium such as cooling water flows, and the object W is cooled by flowing the cooling medium through this cooling flow path 61.

The cooling passage 61 has a blade passage 63, a connecting passage 65, and an axial passage 67. The blade passages 63 are formed in a set of three on each blade 55. These three blade passages 63 extend in parallel along the blade 55.

The inner surfaces 63a of the blades 55 on the outer surface 55a side of the blades 55 are arranged parallel to the outer surface 55a of the blades 55. Furthermore, the three blade flow paths 63 provided on each blade 55 are each arranged at an equal distance from the outer surface 55a of the blades 55.

The connecting channels 65 are formed at both ends of the blade 55. These connecting channels 65 extend in a direction intersecting the blade 55 at the end of the blade 55, and are alternately connected to adjacent blade channels 63. As a result, the cooling channel 61 is a path in which the blade channel 63 is folded back by the connecting channel 65 at the end of the blade 55. The axial channel 67 is formed in the center of the shaft body 51. One end of the axial channel 67 is connected to one of the blade channels 63 via the connecting channel 65.

The cooling flow passage 61 has a start end 61S at the end of the axial flow passage 67 opposite the side communicating with the blade flow passage 63, and a finish end 61E at the end of the blade flow passage 63 that is not communicating with the connecting flow passage 65. The cooling flow passage 61 is continuous from the start end 61S to the finish end 61E. In other words, the cooling flow passage 61 runs from the start end 61S of the axial flow passage 67 at one end of the shaft body 51 through the blade flow passage 63 and the connecting flow passage 65 alternately, turns around at the end of the blade 55, and reaches the finish end 61E at the end of the blade flow passage 63.

FIG. 4 is a cross-sectional view of a blade flow passage 63 for explaining the cross-sectional shape of the cooling flow passage 61.
4, the corners of the blade flow passages 63 of the cooling flow passage 61 are formed in an arc shape in a cross section perpendicular to the extension direction, which alleviates stress concentration at the corners of the cooling flow passage 61. For example, when forming the cooling flow passage 61 by stacking the weld beads B, fillet welds Bs are applied to the corners between the side wall portions and the bottom portion to form an R-shape, or when forming the ceiling portion that closes the upper part of the side wall portions, the weld beads B are stacked to overhang so that the corners between the side wall portions and the ceiling portion have an R-shape.

Next, we will explain the manufacturing system for manufacturing the above-mentioned object W. Figure 5 is a schematic diagram of the manufacturing system 100 for manufacturing the object W.

As shown in FIG. 5, the object manufacturing system 100 of this configuration includes a welding robot 11, a robot controller 13, a filler metal supply unit 15, a welding power source 19, and a control unit 21.

The welding robot 11 is an actuator consisting of a multi-joint robot, and a torch 23 is supported on the tip shaft. The position and posture of the torch 23 can be set arbitrarily in three dimensions within the range of the degrees of freedom of the robot arm. The torch 23 holds a linear filler metal (welding wire) M, which is continuously supplied from the filler metal supply unit 15, in a state where it protrudes from the tip of the torch.

The torch 23 has a shield nozzle (not shown), and shield gas is supplied to the welded portion from the shield nozzle. The arc welding method may be either a consumable electrode type such as shielded metal arc welding or carbon dioxide gas arc welding, or a non-consumable electrode type such as TIG welding or plasma arc welding, and is selected appropriately depending on the object to be produced.

For example, in the case of a consumable electrode type, a contact tip is placed inside the shield nozzle, and the filler material M to which a melting current is supplied is held by the contact tip. The torch 23 holds the filler material M and generates an arc from the tip of the filler material M in a shielding gas atmosphere. The filler material M is fed to the torch 23 by a payout mechanism (not shown) attached to a robot arm or the like. Then, as the torch 23 moves, the continuously fed filler material M is melted and solidified, forming a weld bead B, which is a molten solidified body of the filler material M.

The heat source for melting the filler material M is not limited to the arc described above. For example, other heat sources may be used, such as a heating method that combines an arc and a laser, a heating method that uses plasma, or a heating method that uses an electron beam or laser. When heating with an electron beam or laser, the amount of heat can be controlled more precisely, and the state of the weld bead B can be more appropriately maintained, contributing to further improving the quality of the molded object W.

Any commercially available welding wire can be used as the filler material M. For example, wires specified in MAG and MIG welding solid wires for mild steel, high tensile steel and low temperature steel (JIS Z 3312), arc welding flux-cored wires for mild steel, high tensile steel and low temperature steel (JIS Z 3313), etc. can be used.

An active metal such as titanium can also be used as the filler metal M. In that case, it is necessary to place the weld in a shielding gas atmosphere to prevent oxidation and nitridation due to reaction with the atmosphere during welding.

The robot controller 13 receives instructions from the control unit 21 to drive each part of the welding robot 11 and control the output of the welding power source 19 as necessary.

The control unit 21 is configured with a computer device equipped with a CPU, memory, storage, etc., and executes a drive program prepared in advance or a drive program created under desired conditions to drive each part such as the welding robot 11.

The manufacturing system 100 configured as described above moves the torch 23 by driving the welding robot 11 along a movement trajectory of the torch 23 generated from the set layer shape data, and while rotating the shaft body 51 around its axis, the torch 23 deposits a weld bead B made of molten filler metal M around the shaft body 51. This produces a molded object W in which a molded portion 53 made of the weld bead B is formed on the outer periphery of the shaft body 51. Both ends of the shaft body 51 are supported by supports 49 provided on the base 47, making it rotatable.

Next, a method for producing a shaped object according to the present invention will be described.
(Axial flow passage forming process)
First, a hole is drilled from one end in the center of the shaft body 51 to form the axial passage 67. Furthermore, a hole is formed in the radial direction near the other end of the shaft body 51 to form a part of the connecting passage 65 connected to the axial passage 67.

(Wing section molding process)
While rotating the shaft body 51, a shaping portion 53 having a blade 55 is formed on the outer periphery of the shaft body 51. Specifically, a weld bead B is repeatedly formed along the extension direction of the blade 55 to be formed. In this way, the weld beads B are layered on the outer periphery of the shaft body 51 to form the shaping portion 53 having the blade 55.

At this time, when the blade 55 is shaped, a flow passage forming process is performed in which a gap is created between the weld beads B to form a hollow portion, thereby forming the blade flow passage 63 and the connecting flow passage 65 surrounded by the weld beads B. This forms a cooling flow passage 61 with a continuous path from the starting end 61S, which is the inlet, to the ending end 61E, which is the outlet.

Here, a method for forming the blade flow passages 63 in the flow passage forming step will be described by taking as an example a case where the blade flow passages 63 are formed in the outermost peripheral portion of the blade 55.
Fig. 6 is a side view of a partially-formed object W, illustrating how the blade flow passage 63 is formed in the blade-forming process. Fig. 7 is a cross-sectional view of a portion of a partially-formed blade 55, illustrating how the blade flow passage 63 is formed in the blade-forming process.

As shown in Figures 6(A) and 7(A), the weld bead B is extended in parallel along the path of the wing flow passage 63. This forms a groove G in the path of the wing flow passage 63. At this time, fillet welds Bs are applied to the corners between both side walls and the bottom of the groove G to form an R-shape (see Figure 4).

Next, as shown in Fig. 6(B) and Fig. 7(B), multiple welding beads B are formed on the upper edge of the groove G along the groove G so as to close the upper part of the groove G. Specifically, the welding beads B that overhang from the upper edge of the groove G are repeatedly stacked to form a ceiling portion, forming the wing passage 63. At this time, the corners of the wing passage 63 are formed in an arc shape in a cross-sectional view perpendicular to the extension direction (see Fig. 4). In addition, the welding beads B are stacked so that the inner surface 63a of the wing passage 63 on the side of the outer surface 55a of the blade 55 is parallel to the outer surface 55a of the blade 55, thereby forming the blade 55 (see Fig. 3).

In the object W thus formed, the cooling medium is sent from the starting end 61S to the axial flow passage 67, flows alternately through the connecting flow passage 65 and the blade flow passage 63, and is discharged from the end 61E (see FIG. 2). As a result, the object W is cooled by the cooling medium flowing through the cooling flow passage 61.

When a bending load acts on the object W, which is a rotating body rotating around the axis Ax (see Figure 2), a principal stress consisting of a tensile force is generated along the axis Ax in the part on the outside of the bend, and the principal stress is maximum in the central part in the axial direction.

In the object W of this configuration, the wing passage 63 of the cooling passage 61 has a width dimension Wc in a cross section perpendicular to the extension direction as shown in Figures 8(A) and 8(B), and a width dimension WAx in a cross section along the axis Ax as shown in Figures 8(A) and 8(C) that is larger than the width dimension Wc in a cross section perpendicular to the extension direction.

In this way, in the molded object W of this configuration, the blade flow passage 63 of the cooling flow passage 61 has a large width dimension WAx in the cross section along the axis Ax, so the stress concentration coefficient is small. Therefore, even in the central part in the axial direction where the principal stress is maximum when a bending load is applied, the effect of the principal stress can be suppressed.

As described above, according to the present configuration of the molded object W and the method for manufacturing the molded object W, a cooling flow path 61 is provided in which a plurality of wing passages 63 extending parallel to the blade 55 are connected to the connecting passage 65 at the end of the blade 55 and folded back, so that the area of the inner surface of the cooling flow path 61 within the blade 55 can be increased. This can increase the efficiency of heat exchange with the blade 55 when a cooling medium is passed through the cooling flow path 61, resulting in a molded object W with excellent cooling capacity.

In addition, the blade passage 63 extending parallel to the blade 55 has a large width dimension WAx in the cross section along the axis Ax, which is the principal stress direction, and this helps to reduce stress concentration when stress acts in the axial direction due to bending load.

In addition, the cooling flow path 61 is formed as a continuous path from the start end 61S, which is the inlet, to the end end 61E, which is the outlet. This makes it easy to determine whether or not there is a blockage in the cooling flow path 61 by circulating the cooling medium through the cooling flow path 61.

In addition, when forming a blade 55 having a cooling passage 61 by stacking the weld beads B, the weld beads B can be formed continuously along the path of the blade passage 63, thereby reducing the start and end points of the weld beads B and increasing productivity.

Furthermore, the corners of the cooling flow passage 61 are formed in an arc shape when viewed in a cross section perpendicular to the extension direction. Therefore, stress concentration at the corners of the cooling flow passage 61 can be alleviated.

In addition, the inner surface 63a of the blade passage 63 on the side of the outer surface 55a of the blade 55 is arranged parallel to the outer surface 55a of the blade 55. This makes it possible to make the thickness between the outer surface 55a of the blade 55 and the blade passage 63 uniform, and when a cooling medium is flowed through the cooling passage 61, the outer surface 55a of the blade 55 can be cooled in a balanced manner.

Moreover, the multiple vane flow passages 63 provided on the blade 55 are each disposed at an equal distance from the outer surface 55a of the blade 55. Therefore, when a cooling medium is caused to flow through the cooling flow passage 61, the multiple vane flow passages 63 provided on the blade 55 can cool the entire blade 55 in a balanced manner.

As such, the present invention is not limited to the above-described embodiment, and the invention also contemplates the mutual combination of the various components of the embodiment, as well as modifications and applications by those skilled in the art based on the description in the specification and well-known technology, and these are included in the scope of the protection sought.

As described above, the present specification discloses the following:
(1) A structure comprising a rotor having a plurality of wing portions formed from a welded metal around a shaft body made of a base metal, a hollow flow passage provided therein, and rotated around the axis of the shaft body,
The flow path is
A plurality of blade flow passages are provided within the blade portion and extend parallel to the blade portion;
A connecting flow passage extending in a direction intersecting the wing portion at an end of the wing portion;
having
A shaped object, wherein the connecting flow passages are alternately connected to adjacent wing flow passages, and the paths of the flow passages are folded back at the ends of the wing portions.
In the structure of this configuration, the blade passages extending parallel to the blade are connected to the connecting passage at the end of the blade to provide a passage that turns back, so that the area of the inner surface of the passage within the blade can be increased, thereby increasing the efficiency of heat exchange with the blade when a cooling medium is passed through the passage, and resulting in a structure with excellent cooling capacity.
Furthermore, the blade flow passage extending parallel to the blade portion has a large width dimension in a cross section along the axis, which is the principal stress direction, so that stress concentration when stress acts in the axial direction due to bending load can be alleviated.

(2) The object according to (1), wherein the flow path is formed as a continuous path from the inlet to the outlet.
In a molded object having this configuration, the flow path is formed as a continuous route from the inlet to the outlet, so that by circulating the cooling medium through the flow path, it is possible to easily determine the presence or absence of a blockage in the flow path.
In addition, when forming a wing portion having a flow passage by stacking weld beads, the weld beads can be formed continuously along the path of the wing portion flow passage, thereby reducing the start and end points of the weld beads and increasing productivity.

(3) The shaped object according to (1) or (2), wherein the flow path has corners formed in an arc shape in a cross section perpendicular to the extension direction.
In a shaped object having this configuration, the corners of the flow passage are formed in an arc shape, so that it is possible to reduce stress concentration at the corners of the flow passage.

(4) The object according to any one of (1) to (3), wherein the inner surface of the blade flow passage on the outer surface side of the blade is arranged parallel to the outer surface of the blade.
In the object having this configuration, the inner surface of the blade passage on the outer surface side of the blade is arranged parallel to the outer surface of the blade, which makes it possible to make the thickness between the outer surface of the blade and the blade passage uniform, and to cool the outer surface of the blade in a balanced manner when a cooling medium is flowed through the passage.

(5) The object according to any one of (1) to (3), wherein the plurality of wing flow paths provided in the wing are disposed at equal distances from an outer surface of the wing.
According to a molded object having this configuration, when a cooling medium is caused to flow through the flow passages, the entire blade can be cooled in a balanced manner by the plurality of blade flow passages provided in the blade.

(6) A method for producing a shaped object according to any one of (1) to (5), comprising the steps of:
A wing portion forming process includes forming the wing portion by laminating a weld bead formed by melting and solidifying a filler material on an outer periphery of the shaft while rotating the shaft,
A method for manufacturing a molded object, in which, in the wing portion forming process, a flow path forming process is performed in which the weld bead is extended parallel to the path of the wing portion flow path, so as to be continuous with the portion along the connecting flow path, and laminated to form the flow path.
According to the manufacturing method of the object having this configuration, when molding the wing portion, it is possible to form a flow path having a plurality of wing portion flow paths that turn back at a connecting flow path at the end. Also, when molding the wing portion having a flow path by stacking weld beads, it is possible to form the weld beads continuously, which reduces the start and end points of the weld beads and increases productivity.

(7) The method for manufacturing a shaped object according to (6), wherein in the flow path forming step, the weld bead is formed so that a portion that becomes a corner in a cross-sectional view perpendicular to an extension direction of the flow path has an arc shape.
According to the manufacturing method of a shaped object having this configuration, a flow path can be formed with arc-shaped corners, and stress concentration at the corners of the flow path can be alleviated.

(8) The method for manufacturing a molded object according to (6) or (7), wherein in the wing portion forming process, the wing portion is formed by stacking the weld beads so that the inner surface of the wing portion in the wing portion flow path on the outer surface side is parallel to the outer surface of the wing portion.
According to this method for manufacturing a molded object, the inner surface of the blade passage on the outer surface side of the blade is arranged parallel to the outer surface of the blade, which makes it possible to make the thickness between the outer surface of the blade and the blade passage uniform, and allows the outer surface of the blade to be cooled in a balanced manner when a cooling medium is passed through the passage.

51 Shaft body 55 Blade (wing portion)
55a Outer surface 61 Cooling channel (channel)
61S Beginning (entrance)
61E Termination (Exit)
63: Wing passage 63a: Inner surface 65: Connecting passage B: Weld bead W: Molded object

Claims (8)

A molded object is a rotor having a plurality of blades made of welded metal around a shaft body made of a metal base material, a hollow flow path is provided inside, and the rotor is rotated around an axis of the shaft body,
The wing portion is formed such that a protruding portion on an outer circumferential side of the shaft body extends in an axial direction of the shaft body in a spiral twisted shape,
The flow path is
A plurality of blade flow passages are provided within the blade portion and extend parallel to the blade portion;
A connecting flow passage extending in a direction intersecting the wing portion at an end of the wing portion;
having
The connecting flow passages are alternately connected to the adjacent wing flow passages, and the paths of the flow passages are turned back at the ends of the wing portions.
A sculpture. The flow path is formed as a continuous path from the inlet to the outlet.
The shaped object according to claim 1 . The flow path has a corner formed in an arc shape in a cross-sectional view perpendicular to the extension direction.
The shaped object according to claim 1 or 2. The blade flow passage has an inner surface on the outer surface side of the blade, the inner surface being arranged parallel to the outer surface of the blade.
The shaped object according to any one of claims 1 to 3. The plurality of wing passages provided in the wing are disposed at equal distances from an outer surface of the wing.
The shaped object according to any one of claims 1 to 3. A method for producing a shaped object according to any one of claims 1 to 5, comprising the steps of:
A wing portion forming process includes forming the wing portion by laminating a weld bead formed by melting and solidifying a filler material on an outer periphery of the shaft while rotating the shaft,
In the wing portion forming step, a flow passage forming step is performed in which the weld bead is extended in parallel along the path of the wing portion flow passage to be continuous with the portion along the connecting flow passage and laminated to form the flow passage.
A method for manufacturing a sculpture. In the flow channel forming step, the weld bead is formed so that a corner portion in a cross-sectional view perpendicular to an extension direction of the flow channel has an arc shape.
The method for producing a shaped object according to claim 6 . In the blade portion forming step, the weld beads are laminated to form the blade portion such that an inner surface of the blade portion in the blade portion flow path on the outer surface side of the blade portion is parallel to an outer surface of the blade portion.
The method for producing a shaped object according to claim 6 or 7.

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