JP7364504B2 - Impeller and impeller manufacturing method - Google Patents

Description

The present invention relates to an impeller and a method for manufacturing an impeller.

Generally, impellers used in centrifugal pumps, generators, etc. for fluids such as liquids and gases are known (Patent Documents 1 and 2).
As shown in FIG. 10, Patent Document 1 describes a shroud (first disk portion) 101, a plurality of blades (vane portions) 103 formed spirally and radially around the center of the shroud, and the shroud 101 and An impeller 100 is disclosed that includes a hub (second disk portion) 102 that is arranged to face each other and comes into contact with a plurality of blades 103. This impeller 100 is assembled by fitting a hole 104 formed in a shroud 101 with a convex part 105 formed in a blade 103.

As shown in FIG. 11(A), Patent Document 2 describes a hub 201 that rotates around a rotating shaft, a shroud 202 that is provided opposite to the hub 201, and a shroud that is provided between the hub 201 and the shroud 202. An impeller 200 is disclosed that includes a plurality of blades 203 and a plurality of boost passages 204 defined by a hub 201, a shroud 202, and a plurality of blades 203. The boost flow path 204 of this impeller 200 is a through hole extending linearly from the inlet 204a to the outlet 204b. Since the boosting flow path is formed by a through hole, the hub 201, the shroud 202, and the plurality of blades 203 do not need to be manufactured separately, and can be formed integrally.

JP 2019-190332 Publication JP2019-157710A

The impeller has a structure that compresses and discharges fluid flowing into the impeller while rotating in a direction perpendicular to the flow direction of the fluid. Typically, an open impeller is made up of a hub having a disk portion and a plurality of blades provided on the disk surface of the hub, or a hub having a disk portion and an impeller arranged facing the hub at a predetermined distance from the hub. There is a closed impeller, etc., which consists of a shroud that serves as the other disk portion, and a plurality of blades provided between the hub and the shroud.

In the closed impeller, a fluid flow path is formed in a space defined by a hub and a shroud that face each other, and a pair of blades that are provided between the hub and the shroud and face each other. The fluid path of the fluid flow path is determined by a plurality of blades arranged radially from near the center of the hub and shroud.

The following points are required for designing and manufacturing such an impeller.
(1) Unlike an open impeller, a closed impeller requires a shroud that forms a ceiling, and is more complicated and difficult to manufacture than an open impeller. Therefore, efficient manufacturing methods are required.
(2) Since the impeller rotates at high speed, compresses the fluid, and forcibly changes the direction of the fluid, it is required to have strength and to reduce the stress load. Therefore, there is a need for a method that can flexibly design the cross-sectional shape of the fluid flow path.
(3) Impellers are required to be lightweight in order to increase the number of revolutions.

The configurations of Patent Documents 1 and 2 will be explained in more detail while taking into account the above requests.
In the case of the closed impeller of Patent Document 1, it is necessary to weld (including brazing) the shroud 101 and the plurality of blades 103. However, since there are many welding points and the shape is complicated, welding is difficult and the welded shape may become unstable. Moreover, since large stress is generated in the shroud 101, if welding quality is not guaranteed, it may lead to a decrease in the strength of the closed impeller. Furthermore, the blade 103 and the hub 102 are similarly welded together. There is a method to reduce the stress by making the welding point into a curved shape, but if you try to increase the radius of curvature of the curved surface, the welding time will increase, a large thermal load will be generated on the blade 103 and the hub 102, and the material properties will be affected. may cause thermal deformation.

Further, the fluid flow path of Patent Document 1 has a radial spiral curve, and tensile stress and compressive stress are concentrated on the impeller rotating at high speed, which may cause damage to the impeller. This point will be explained using FIGS. 12 and 13. 12 shows the closed impeller shown in FIG. 10, and FIG. 13 shows a closed impeller in which the shroud 101 and blades 103 shown in FIG. 10 are welded together.

As shown in (A) of FIG. 12, when fluid F flows into the impeller 100 from the outside of the impeller 100 in the axial direction, the rotating impeller 100 forces the flow direction of the fluid F from the axial direction in the region P1. Can be bent radially. Then, in a region P2 downstream of the region P1, the flow direction is bent in accordance with the curved shape within the fluid flow path 111. At this time, a pressure P is applied to the inner wall surface 103a of the blade 103 in response to a pressing force from the fluid F.

As shown in FIG. 12(B), the pressure P applied to the inner wall surface 103a is concentrated at the boundary 113 (the part surrounded by the broken line) between the blade 103 and the hub 102, and a large tensile stress is generated.

In order to alleviate the above-mentioned tensile stress, it is advisable to form a curved surface portion 115 as shown by a broken line in the boundary portion 113, as shown in FIG. 12(C). However, it is not easy to form the curved surface portion 115 during welding. In reality, when welding the blade 103 and the hub 102, the amount of heat input during welding is minimized to prevent deformation of the blade 103 due to heat input during welding and the inability to maintain strength due to changes in the metal structure. It is kept to a minimum. Therefore, the curved surface portion 115 of the boundary portion 113 has a radius of curvature MR smaller than the plate thickness BT of the blade 103, and a necessary and sufficient stress relaxation effect cannot be obtained.

Moreover, the above-mentioned tensile stress is generated in the same way at the joint between the shroud and the blade when the shroud and the blade are welded together.
A schematic axial cross section of the impeller 100 is shown in FIG. 13(A). As shown in (A) of FIG. 13, when the fluid F flows at high speed in the fluid flow path 201, pressure increases in the axial direction (downward in (A) of FIG. 13) in the region P1 of the fluid flow path 111. join. At this time, a large compressive stress is applied to the boundary part 117 (the part surrounded by a broken line: that is, the boundary part 117 where one end of the blade 103 in the extending direction is located) which is the connecting part between the shroud 101 and the blade 103. Furthermore, as shown in FIG. 13B, a large compressive stress is also applied to the boundary 119 between the shroud 101 and the blade 103 (the part surrounded by the broken line: that is, the boundary 119 along the entire length of the blade 103). .

In order to alleviate such compressive stress, it is a good idea to form a curved surface part 121 at the boundary part 119 (same as for 117), as shown in FIG. 13(C). However, as in the case of tensile stress described above, the curved surface portion 121 can only form a radius of curvature MR smaller than the plate thickness BT of the blade 103, and a necessary and sufficient stress relaxation effect cannot be obtained.

On the other hand, in the impeller of Patent Document 2, the cross-sectional shape of the boost flow path 204 is a circular elongated hole. However, the pressure boost flow path 204 is formed in a straight line by cutting such as drilling, and it is difficult to form a curved pressure rise flow path such as a spiral curve. Furthermore, a configuration in which a plurality of linear channels are connected to each other can be considered, but in that case, welding or brazing, etc., would be required, and the above-mentioned problem of stress concentration would occur.

Further, in the configurations of Patent Documents 1 and 2, it is difficult to reduce the weight while increasing the mechanical strength.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an impeller with high strength, a high degree of freedom in design of shape, and an easily lightweight impeller, and a method for manufacturing the impeller.

The present invention consists of the following configuration.
(1) A hub having a first disk portion centered on the axis;
a plurality of blades that are arranged to extend radially in the first disc part and guide fluid flowing in along the axis as the hub rotates from a radial inside of the first disc part to a radial outside of the first disc part; ,
a shroud having a second disk portion disposed opposite to the first disk portion with the blade in the direction of the axis;
Equipped with
The blades are curved and arranged at intervals in a circumferential direction about the axis,
A fluid flow path defined by a plurality of the blades is formed between the first disc part and the second disc part,
A curved surface portion having a radius of curvature larger than a wall thickness of the blade in a cross section orthogonal to the longitudinal direction of the fluid flow path is formed on a portion of the inner wall surface of each of the hub, the blade, and the shroud surrounding the fluid flow path. Impeller provided.
(2) A method for manufacturing the impeller according to (1), comprising:
supplying metal powder to a predetermined thickness onto the base, melting and solidifying the supplied metal powder by irradiation with laser light to form a built-up layer;
The procedure of newly supplying the metal powder to a predetermined thickness on the formed overlay layer, melting and solidifying the metal powder by irradiation with laser light is repeated, and a plurality of overlay layers are sequentially laminated. The process of
has
A method for manufacturing an impeller, comprising layer-manufacturing the built-up layer into the shape of the impeller.

According to the present invention, the impeller can be made to have high strength, increase the degree of freedom in designing the shape, and easily reduce the weight.

FIG. 1 is a partially cutaway perspective view of an impeller according to a first embodiment of the present invention. FIG. 2 is a side view of the impeller shown in FIG. 1. 3 is a partially enlarged side view of the impeller shown in FIG. 2. FIG. FIG. 4 is a partially enlarged side view of the impeller showing a second embodiment of the fluid flow path. FIG. 5 is a partially enlarged side view of the impeller showing a third embodiment of the fluid flow path. FIG. 6 is a partially enlarged side view of the impeller showing a fourth embodiment of the fluid flow path. FIGS. 7A and 7B are partially enlarged side views of an impeller showing a fifth embodiment of a fluid flow path. FIG. 8 is a partially enlarged side view of the impeller showing a sixth embodiment of the fluid flow path. FIGS. 9A and 9B are partially enlarged side views of an impeller showing a seventh embodiment of a fluid flow path. FIG. 10 is an exploded perspective view of a conventional impeller. FIG. 11 shows another conventional impeller, in which (A) is a schematic sectional view showing a meridional section of the impeller, and (B) is a perspective view of the impeller. FIG. 12 is a diagram illustrating problems with the prior art, in which (A) is a partial schematic perspective view of an impeller, (B) is a cross-sectional view taken along the line XII-XII of (A), and (C) is a curved portion ( It is a XII-XII line view of A). FIG. 13 is a diagram illustrating the problems of the prior art, in which (A) is a schematic axial cross-sectional view of an impeller, (B) is a cross-sectional view taken along the line XIII-XIII of (A), and (C) is a curved part formed. It is a sectional view taken along the line XIII-XIII of (A).

Hereinafter, configuration examples of the present invention will be described in detail with reference to the drawings.
Here, various embodiments will be described in which the shape of the fluid flow path along the blades of the closed impeller is changed to various shapes.

<First embodiment>
FIG. 1 is a partially cutaway schematic perspective view of an impeller according to a first embodiment of the present invention. FIG. 2 is a side view of the impeller shown in FIG. 1.

The impeller 1 is used, for example, in a gas turbine, an engine supercharger, a steam turbine, etc., and is made of a metal material such as steel. The impeller 1 shown in FIG. 1 includes a hub 10, a plurality of blades 20, and a shroud 30, and is driven to rotate about an axis X. The hub 10 includes a first cylindrical portion 11 that is provided near the axis X and extends along the axis X, and a first disk portion that is arranged in a direction perpendicular to the axial direction of the first cylindrical portion 11 and is circular in plan view. 12. The blades 20 are formed on the first disk portion 12 so as to stand up along the axis X direction, are spaced from each other in the circumferential direction centering on the axis X, are curved in a spiral manner, and have a diameter. They are arranged to extend radially outward.

The shroud 30 is placed opposite the hub 10 with the blade 20 in between. The shroud 30 includes a second cylindrical portion 31 that is provided near the axis X and extends in the direction of the axis X, and a second disk portion 32 that is arranged in a direction perpendicular to the axial direction of the second cylindrical portion 31 and is circular in plan view. and has. The hub 10, the blades 20, and the shroud 30 are integrally laminated by a three-dimensional laminated molding method using metal powder.

The first cylindrical portion 11 and the second cylindrical portion 31 are arranged facing each other in the vicinity of the axis X with a predetermined distance maintained in the radial direction. That is, the first cylindrical portion 11 is an inner cylindrical portion and the second cylindrical portion 21 is an outer cylindrical portion, forming a double cylinder arrangement, forming an inlet side fluid flow path 40 for fluid flowing from the outside of the impeller 1. . The first disc part 12 and the second disc part 32 are arranged in parallel and facing each other with a predetermined interval, and a plurality of blades 20 are provided between the first disc part 12 and the second disc part 32. A partitioned fluid flow path 41 is formed.

The fluid flow paths 41 are formed radially along the curved shape of the blade 20, and guide fluid radially outward from the inner peripheral edge 20a of the blade 20 near the axis X toward the outer peripheral edge 20b. Furthermore, the inner circumferential edge 20 a of the blade 20 is connected to the inner circumferential edge 13 of the first disk portion 12 and the inner circumferential edge 33 of the second disk portion 32 . The inner peripheral edge 13 is connected to the first cylindrical part 11 , and the inner peripheral edge 33 is connected to the second cylindrical part 31 . That is, the inner peripheral portion of the impeller 1 is provided with a connecting portion 42 in which the fluid flow path 41 and the inlet side fluid flow path 40 are bent and connected. The connecting portion 42 has a smooth curved shape with an axial cross-sectional shape bent at approximately 90 degrees to change the direction of the fluid.

As shown in FIG. 2, a pair of blades 20 forming one fluid flow path 41 each have blade inner wall surfaces 51 on opposite sides. The first disc part 12 and the second disc part 32 have a first disc part inner wall surface 52 and a second disc part inner wall surface 53 on opposing sides, respectively. That is, the fluid flow path 41 is configured as a space defined by a pair of blade inner wall surfaces 51 and a pair of first disk inner wall surfaces 52 and second disk inner wall surfaces 53. In the following description, each inner wall surface is also collectively referred to as an inner wall surface 50 (see FIG. 3).

In addition, a pair of connected portions between the blade inner wall surface 51 and the first disc inner wall surface 52 shown in FIG. It's called 60B.

Generally speaking, the metal powder additive manufacturing method for manufacturing the impeller 1 with this configuration first supplies metal powder, which is a material for modeling, onto a base at a predetermined thickness, and then irradiates the surface of the metal powder with a laser beam. The metal powder is irradiated to melt and solidify to form a built-up layer. The process involves newly supplying metal powder to a predetermined thickness on top of this build-up layer, melting and solidifying the metal powder by irradiation with laser light, and laminating a new build-up layer on top of the build-up layer. This is a method of repeatedly stacking overlay layers one after another to obtain a shaped body of a desired shape.

Specifically, first, the hub 10 is stacked while repeating the arrangement of metal powder, melting, and solidification of the metal powder, and a plurality of blades 20 are stacked on the first disk portion 12 of the hub 10 . At this time, when forming the blade 20, a curved surface portion 70 is formed at the boundary portion 60A. Further, the second disk portion 32 of the shroud 30 is formed on the blade 20. At the same time, the first cylindrical part 11 and the second cylindrical part 21 are also formed. Through the above steps, the impeller 1 is layered and manufactured.

That is, according to the metal powder additive manufacturing method, a desired shape can be automatically manufactured from three-dimensional shape data (for example, CAD data), and even complex shapes can be easily manufactured.

Next, the shape of the fluid flow path 41 will be explained in detail.
FIG. 3 is a partially enlarged side view of the impeller 1 shown in FIG. 2. FIG.
In the impeller 1 having this configuration, a curved surface portion 70 is formed at the boundary portion 60A in order to relieve stress generated at the boundary portion 60A. The radius of curvature R of the curved surface portion 70 is larger than the thickness ta of the blade 20. The wall thickness ta here is the wall thickness that is the minimum distance between a pair of blade inner wall surfaces 51 of one blade 20, and also the minimum thickness of one blade 20.

Moreover, although the first disc inner wall surface 52 shown in FIG. 3 is entirely formed into a curved surface, the intermediate portion excluding the curved surface portions 70 at both ends in the circumferential direction may be flat.

By forming the curved surface part 70 in the boundary part 60A, stress concentration is less likely to occur in the boundary part 60A even when a pressing force from a fluid acts during operation of the impeller, and the strength of the impeller 1 is increased. Note that the length of the radius of curvature R of the curved surface portion 70 described above is the same in each embodiment described below.

Further, the thickness tb of the first disk portion inner wall surface 52 and the wall thickness tc of the second disk portion inner wall surface 53 are formed to be thinner than the thickness ta of the blade 20 (ta>tb, ta>tc). Further, it is preferable that the inner wall surface 52 of the first disk portion of the hub 10 is formed in a curved shape so that the thickness tb at the center in the circumferential direction is thinner than at both ends. Such thinning reduces the weight of the impeller 1 as a whole, and the centrifugal force generated can be reduced even at the same rotational speed of the impeller 1. Therefore, in this respect as well, the strength of the impeller 1 is relatively improved, and higher speed rotational driving becomes possible.

The impeller 1 having the above-mentioned shape is manufactured by the metal powder additive manufacturing method, so that the radius of curvature R of the curved surface portion 70 and the shape of the inner wall surface 50 can be freely set. Therefore, the processing is not complicated, the degree of freedom in design is improved, and the necessary and sufficient strength can be easily obtained.

<Second embodiment>
FIG. 4 is a partially enlarged side view of the impeller 1A showing a second embodiment of the fluid flow path 41. As shown in FIG.
The impeller 1A of the present embodiment has a curved surface portion 70 having a radius of curvature R larger than the wall thickness ta of the blades 20 at a boundary portion 60B between the pair of blade inner wall surfaces 51 and the second disk portion inner wall surface 53 of the shroud 30. Each is formed. Further, the curved surface portion 70 is not formed at the boundary portion 60A between the pair of blade inner wall surfaces 51 and the first disk portion inner wall surface 52. That is, in the impeller 1A of the present embodiment, the boundary portion 60B is made into the curved surface portion 70 instead of the boundary portion 60A in the first embodiment which is made into the curved surface portion 70. Other configurations are similar to those of the first embodiment.

Also in the impeller 1A of this embodiment, stress concentration is less likely to occur at the boundary portion 60B, as in the first embodiment, and the strength of the impeller 1A is increased. Furthermore, the thickness tb of the first disk inner wall surface 52 and the thickness tc of the second disk inner wall surface 53 are formed thinner than the thickness ta of the blade 20 (ta>tb, ta>tc). The weight of the entire impeller 1A is reduced, and the centrifugal force generated can be reduced even at the same rotational speed of the impeller 1A. Therefore, also in this respect, the strength of the impeller 1A is relatively improved, and higher speed rotational driving becomes possible.

<Third embodiment>
FIG. 5 is a partially enlarged side view of the impeller 1B showing a third embodiment of the fluid flow path 41. As shown in FIG.
In the impeller 1B of this embodiment, the curved surface portion 70 is formed on both the boundary portion 60A and the boundary portion 60B. Other configurations are similar to those of the first embodiment. In other words, the third embodiment has a configuration in which the curved surface portion 70 of the first embodiment and the curved surface portion 70 of the second embodiment are combined.

According to the impeller 1B having this configuration, all the boundary portions 60A and 60B have the curved surface portions 70, so that stress concentration is less likely to occur over the entire inner wall surface 50 of the fluid flow path 41. In addition, the structure is more lightweight.

<Fourth embodiment>
FIG. 6 is a partially enlarged side view of the impeller 1C showing a fourth embodiment of the fluid flow path 41.
In the impeller 1C of this configuration, the inner wall surface 50 on the hub 10 side has a pair of slopes 54, 55, and the cross-sectional shape of the fluid flow path 41 in the longitudinal direction (flow direction) orthogonal cross section is triangular (approximately triangular). , a substantially isosceles triangle in FIG. 6). Each corner of this triangular shape is formed by an arbitrary curve including a circular arc (including a perfect circle or an elliptical arc), a parabola, etc. (that is, it is rounded). The positional relationship between the base and oblique sides of the substantially isosceles triangle may be reversed, and a pair of oblique sides may be provided on the second disk portion 32 side.

According to the impeller 1C having this configuration, the cross-sectional shape of the fluid flow path 41 is triangular, and each corner is formed in a curved shape, so that stress concentration is less likely to occur, similar to the curved surface portion 70 described above. .

<Fifth embodiment>
FIGS. 7A and 7B are partially enlarged side views of impellers 1D and 1E showing a fifth embodiment of a fluid flow path 41. FIGS.
In the impeller 1D of this configuration shown in FIG. 7A, one boundary 60Aa (left side in FIG. 7) of the boundaries 60Aa and 60Ab between the blade inner wall surface 51 and the first disk inner wall surface 52 of the hub 10 The curved surface portion 70 is formed only in this area. Further, as shown in FIG. 7B, the curved surface portion 70 is provided only at the other boundary portion 60Ab (on the right side in FIG. 7) between the blade inner wall surface 51 and the first disc inner wall surface 52 of the hub 10. may be formed.

According to the impellers 1D and 1E having this configuration, by forming the curved surface portion 70 only in the boundary portion 60Aa of the pair of boundary portions 60Aa and 60Ab, tensile stress can be mainly alleviated. Further, by forming the curved surface portion 70 only at the boundary portion 60Ab, compressive stress can be mainly alleviated. Further, the curved surface portion 70 may be formed only at at least one of the boundary portions 60Ba and 60Bb between the blade inner wall surface 51 and the second disk portion inner wall surface 53 of the shroud 30. In that case as well, tensile stress and compressive stress can be selectively relaxed.

According to the above, a high-strength impeller can be constructed by simply forming the curved surface portion 70 in the minimum necessary portions.

<Sixth embodiment>
FIG. 8 is a partially enlarged side view of the impeller 1F showing a sixth embodiment of the fluid flow path 41.
In the impeller 1F having this configuration, the pair of boundary parts 60A and the pair of boundary parts 60B form a curved surface part 70, and the first disk part inner wall surface 52, the second disk part inner wall surface 53, and the pair of blade inner wall surfaces 51 , each has a curved shape that swells toward the outside of the fluid flow path 41.

Further, the first disk portion outer surface 57 outside the first disk portion inner wall surface 52 has a curved shape along the first disk portion inner wall surface 52, and the wall thickness tb on the first disk portion 12 side is approximately constant, and the blade It is formed thinner than the wall thickness ta of No. 20. Similarly, the second disk portion outer surface 58 on the outside of the second disk portion inner wall surface 53 has a curved shape along the second disk portion inner wall surface 53, and the wall thickness tc on the second disk portion 32 side is approximately constant; It is formed thinner than the wall thickness ta of the blade 20.

According to the impeller 1F having this configuration, since the first disk portion outer surface 57 and the second disk portion outer surface 58 have a curved shape along the inner wall surface 50, the first disk portion outer surface 57 overlaps with the blade 20. A recess 80 recessed in the axial direction is formed on the outer surface 58 of the second disk portion. The recesses 80 are formed radially along the blade 20. The thickness tb of the first disk portion 12 and the thickness tc of the second disk portion 32 are constant and thinner than the thickness ta of the blade 20, and the recess 80 is formed, thereby further reducing the thickness of the impeller 1F. This makes it possible to reduce weight. If the shape of the impeller 1F is formed by cutting or casting, the number of man-hours will increase, but it can be formed easily and efficiently by metal powder additive manufacturing.

<Seventh embodiment>
(A) and (B) of FIG. 9 are partially enlarged side views of impellers 1G and 1H showing a seventh embodiment of a fluid flow path 41.
In the above-mentioned sixth embodiment, the outer surfaces of both the first disc part 12 and the second disc part 32 are curved, and the recessed part 80 is provided along the blade 20. However, in the impeller 1G having this configuration, As shown in FIG. 9(A), the outer surface of only the first disk portion 12 side of the first disk portion 12 and the second disk portion 32 is formed into a curved shape, and only the first disk portion 12 side has a concave portion. 80. The other configurations are the same as those in the sixth embodiment.

Further, as shown in FIG. 9B, the outer surface of only the second disk portion 32 side of the first disk portion 12 and the second disk portion 32 is formed into a curved shape to provide a recess 80. It is also possible to use an impeller 1H.

According to the impellers 1G and 1H of this configuration, the outer surface of either one of the first disc part 12 and the second disc part 32 can be made into a curved shape and the recessed part 80 can be provided. Further thinning and weight reduction can be achieved.

The present invention is not limited to the embodiments described above, and those skilled in the art may combine the configurations of the embodiments with each other, or make changes and applications based on the description of the specification and well-known techniques. This is the intended purpose of the invention and falls within the scope for which protection is sought.

For example, the cross-sectional shape in a cross section perpendicular to the longitudinal direction (flow direction) of the fluid flow path defined by the inner wall surface 50 may be a perfect circle or an ellipse, in addition to a shape in which at least one of the corners is a curved surface. , various shapes such as triangle, trapezoid, rhombus, etc. can be selected, and the shape of the curved surface at the boundary is not limited to a shape with a constant radius of curvature, but any curve such as a Bezier curve or a spline curve can be used. It is possible to select the desired shape.

As mentioned above, the following matters are disclosed in this specification.
(1) A hub having a first disk portion centered on the axis;
a plurality of blades that are arranged to extend radially in the first disc part and guide fluid flowing in along the axis as the hub rotates from a radial inside of the first disc part to a radial outside of the first disc part; ,
a shroud having a second disk portion disposed opposite to the first disk portion with the blade in the direction of the axis;
Equipped with
The blades are curved and arranged at intervals in a circumferential direction about the axis,
A fluid flow path defined by a plurality of the blades is formed between the first disc part and the second disc part,
A curved surface portion having a radius of curvature larger than a wall thickness of the blade in a cross section orthogonal to the longitudinal direction of the fluid flow path is formed on a portion of the inner wall surface of each of the hub, the blade, and the shroud surrounding the fluid flow path. Impeller provided.
According to this impeller, by forming a curved surface portion with a radius of curvature larger than the wall thickness of the blade at a location where stress is concentrated, stress concentration can be reduced and strength can be increased.

(2) The impeller according to (1), wherein the curved surface portion is formed on at least a portion of the boundary between the first disk portion and the blade, on the inner wall surface.
According to this impeller, stress concentration is less likely to occur at the boundary between the first disk portion and the blade.

(3) The impeller according to (1) or (2), wherein the curved surface portion is formed on at least one of a surface on the hub side and a surface on the shroud side of the inner wall surface.
According to this impeller, the wall thickness of the hub and shroud can be reduced, and the weight can be reduced.

(4) The fluid flow path is defined in any one of (1) to (3), wherein the fluid flow path is formed in at least a portion of the boundary between the second disk portion and the blade on the inner wall surface. impeller.
According to this impeller, stress concentration is less likely to occur at the boundary between the shroud and the blades.

(5) The fluid flow path is provided with a connecting portion bent and connected to the inlet side fluid flow path along the axis at the inner peripheral edge of the first disk portion and the second disk portion ( The impeller according to any one of 1) to (4).
According to this impeller, it is possible to reduce stress caused by fluid passing through the bent connection portion.

(6) In any one of (1) to (5), in a cross section orthogonal to the longitudinal direction of the fluid flow path, the cross-sectional shape of the inner wall surface is triangular, and the corners of the triangular shape are curved. Impeller as described.
According to this impeller, since the cross-sectional shape at the corners of the inner wall surface of the fluid flow path is curved, stress concentration at each corner is alleviated and the strength can be increased.

(7) The outer surface of at least one of the shroud and the hub corresponding to the portion forming the fluid flow path is a curved surface along the inner wall surface, according to any one of (1) to (6). Impeller as described.
According to this impeller, the wall thickness of the shroud or hub is reduced, and weight reduction can be achieved.

(8) The impeller according to any one of (1) to (6), wherein outer surfaces of the shroud and the hub corresponding to the portions forming the fluid flow path are curved surfaces that follow the inner wall surface, respectively. .
According to this impeller, the wall thickness of both the shroud and the hub can be reduced, and the weight can be further reduced.

(9) The impeller according to any one of (1) to (8), wherein the wall thickness of the shroud and the hub corresponding to the portion forming the fluid flow path is thinner than the wall thickness of the blade.
According to this impeller, the overall weight can be reduced while ensuring the strength of the blades.

(10) The impeller according to any one of (1) to (9), wherein the shroud, the blade, and the hub are integrally formed by stacking metal materials.
According to this impeller, since it is a laminated structure of metal materials, it can have a high-strength structure with a high degree of freedom in design.

(11) A method for manufacturing an impeller according to any one of (1) to (10), comprising:
supplying metal powder to a predetermined thickness onto the base, melting and solidifying the supplied metal powder by irradiation with laser light to form a built-up layer;
The procedure of newly supplying the metal powder to a predetermined thickness on the formed overlay layer, melting and solidifying the metal powder by irradiation with laser light is repeated, and a plurality of overlay layers are sequentially laminated. The process of
has
A method for manufacturing an impeller, comprising layer-manufacturing the built-up layer into the shape of the impeller.
According to this method of manufacturing an impeller, a curved surface portion having a desired radius of curvature can be efficiently formed at an appropriate location, so a high-strength impeller that is less prone to stress concentration can be manufactured.

1, 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H Impeller 10 Hub 11 First cylindrical part 12 First disc part 20 Blade 30 Shroud 31 Second cylindrical part 32 Second disc part 41 Fluid flow path 42 Connection Part 50 Inner wall surface 51 Inner wall surface of the blade 52 Inner wall surface of the first disk portion 53 Inner wall surface of the second disk portion 54, 55 Slope 57 Outer surface of the first disk portion 58 Outer surface of the second disk portion 60 Boundary portion 70 Curved surface portion

Claims (6)

a hub having a first disk portion centered on the axis;
a plurality of blades that are arranged to extend radially in the first disc part and guide fluid flowing in along the axis as the hub rotates from a radial inside of the first disc part to a radial outside of the first disc part; ,
a shroud having a second disk portion disposed opposite to the first disk portion with the blade in the direction of the axis;
Equipped with
The blades are curved and arranged at intervals in a circumferential direction about the axis,
A fluid flow path defined by a plurality of the blades is formed between the first disc part and the second disc part,
A curved surface portion having a radius of curvature larger than a wall thickness of the blade in a cross section orthogonal to the longitudinal direction of the fluid flow path is formed on a portion of the inner wall surface of each of the hub, the blade, and the shroud surrounding the fluid flow path. established ,
an outer surface of at least one of the shroud and the hub corresponding to a portion forming the fluid flow path is a curved surface along the inner wall surface;
impeller. a hub having a first disk portion centered on the axis;
a plurality of blades that are arranged to extend radially in the first disc part and guide fluid flowing in along the axis as the hub rotates from a radial inside of the first disc part to a radial outside of the first disc part; ,
a shroud having a second disk portion disposed opposite to the first disk portion with the blade in the direction of the axis;
Equipped with
The blades are curved and arranged at intervals in a circumferential direction about the axis,
A fluid flow path defined by a plurality of the blades is formed between the first disc part and the second disc part,
A curved surface portion having a radius of curvature larger than a wall thickness of the blade in a cross section orthogonal to the longitudinal direction of the fluid flow path is formed on a portion of the inner wall surface of each of the hub, the blade, and the shroud surrounding the fluid flow path. established ,
The outer surfaces of the shroud and the hub corresponding to the portions forming the fluid flow path are respectively curved surfaces along the inner wall surface .
impeller. 2. The fluid flow path according to claim 1, wherein a connecting portion is provided at an inner peripheral edge of the first disk portion and the second disk portion to be bent and connected to the inlet side fluid flow path along the axis. 2. The impeller according to 2 . The impeller according to any one of claims 1 to 3 , wherein the wall thickness of the shroud and the hub corresponding to the portion forming the fluid flow path is thinner than the wall thickness of the blade. The impeller according to any one of claims 1 to 4 , wherein the shroud, the blades, and the hub are integrally formed by stacking metal materials. A method for manufacturing an impeller according to any one of claims 1 to 5 , comprising:
supplying metal powder to a predetermined thickness onto the base, melting and solidifying the supplied metal powder by irradiation with laser light to form a built-up layer;
The procedure of newly supplying the metal powder to a predetermined thickness on the formed overlay layer, melting and solidifying the metal powder by irradiation with laser light is repeated, and a plurality of overlay layers are sequentially laminated. The process of
has
A method for manufacturing an impeller, comprising layer-manufacturing the built-up layer into the shape of the impeller.

Images