JP6783191B2 - Impeller and rotating machine - Google Patents

Description

The present invention relates to impellers and rotary machines .

One of the rotating machines equipped with an impeller is a turbocharger. A turbocharger is a rotary machine capable of improving fuel efficiency and reducing CO ₂ compared to a naturally aspirated engine by sending compressed air to an engine to burn fuel.

For example, Patent Document 1 discloses a turbocharger using an impeller that exhibits a predetermined supercharging function.

Jikkenhei 03-10040

Cited Document 1 discloses that a metal ring is provided on the back plate portion of the synthetic resin impeller in order to suppress the tilting deformation of the blade of the impeller and the waviness deformation of the back plate portion.
However, a stress field in multiple directions is generated in the inner layer of the impeller in the radial direction due to centrifugal force, although the stress is not high. Therefore, the inner layer portion of the impeller may not be able to cope with the stress field in multiple directions simply by providing the metal ring on the back plate portion of the impeller.

An object of the present invention is to provide an impeller and a rotating machine in which the inner layer portion of the impeller can cope with a stress field in multiple directions.

The first aspect is an impeller having a front surface, a back surface and a hub surface, and having a long fiber reinforcing portion formed of a long fiber reinforcing material and a short fiber reinforcing portion formed of a short fiber reinforcing material. On the hub surface side, the impeller surface layer portion having a plurality of blades arranged in the circumferential direction and a boss hole penetrating along the direction from the front surface side to the back surface side are provided, and at least a part of the short fibers It is an impeller including an inner layer portion of the impeller having a reinforcing portion.

According to this aspect, the impeller has a long fiber reinforced portion formed of a long fiber reinforced material and a short fiber reinforced portion formed of a short fiber reinforced material. On the other hand, the impeller has a short fiber reinforced portion at least a part of the inner layer portion of the impeller.
The strength anisotropy of the composite material containing the reinforcing fibers differs depending on the fiber length. The longer the fiber, the higher the mechanical strength in the orientation direction, and the shorter the fiber, the less the mechanical strength anisotropy. Therefore, by shortening at least a part of the inner layer portion of the impeller, which is a multi-axis stress field, the impeller has a material structure having mechanical strength corresponding to the stress state.
Therefore, the inner layer of the impeller can handle stress fields in multiple directions.

The second aspect is the impeller of the first aspect in which the surface layer portion of the impeller is a long fiber reinforced portion.

According to this aspect, in the impeller, the fiber lengths of the reinforcing fibers are different between the impeller surface layer portion where the stress is high in the uniaxial direction and at least a part of the impeller inner layer portion where the stress field is multiaxial and low stress. By lengthening the surface layer portion and shortening at least a part of the inner layer portion, the impeller has a material structure having mechanical strength according to the stress state.

The third aspect is the impeller of the first or second aspect in which the long fiber reinforcing material contains reinforcing fibers having a statistically longer fiber length as compared with the short fiber reinforcing material.

According to this aspect, since the fiber length of the long fiber reinforcing material is statistically long, it is possible to increase the mechanical strength of the long fiber reinforcing material in the direction in which high stress is generated. On the other hand, since the fiber length of the short fiber reinforced plastic is statistically short, the mechanical properties corresponding to the multiaxial stress field can be obtained in the short fiber reinforced plastic.

In the fourth aspect, the long fiber reinforcing material has a cumulative volume ratio of reinforcing fibers having a fiber length of 0.2 mm or less of less than 50% and a cumulative volume ratio of reinforcing fibers having a fiber length of 1 mm or more. Is composed of reinforcing fibers having a fiber length of at least 30% or more, and the short fiber reinforcing material is composed of reinforcing fibers having a fiber length of 0.2 mm or less and having a cumulative volume ratio of at least 50% or more. It is an impeller of the third aspect.

According to this aspect, since the fiber length of the long fiber reinforcing material is statistically longer, the mechanical strength in the direction in which high stress is generated in the long fiber reinforcing material can be further increased. On the other hand, since the fiber length of the short fiber reinforcing material is statistically shorter, the mechanical properties of the short fiber reinforcing material further corresponding to the multiaxial stress field can be obtained.

A fifth aspect is the impeller of the fourth aspect, wherein the long fiber reinforcing material is further composed of reinforcing fibers having a fiber length of 1 mm or more and a cumulative volume fraction of reinforcing fibers of at least 50% or more. ..

According to this aspect, since the fiber length of the long fiber reinforcing material is statistically longer, the mechanical strength in the direction in which high stress is generated in the long fiber reinforcing material can be further increased.

A sixth aspect is a fourth or fifth aspect in which the short fiber reinforcing material is further composed of reinforcing fibers having a fiber length of 0.2 mm or less and having a cumulative volume fraction of at least 80% or more. The impeller of the embodiment.

According to this aspect, since the fiber length of the short fiber reinforcing material is statistically shorter, the mechanical properties of the short fiber reinforcing material further corresponding to the multiaxial stress field can be obtained.

A seventh aspect is the impeller of any one of the first to sixth aspects, wherein the short fiber reinforcing portion is formed so as to surround the boss hole.

According to this aspect, since the periphery of the boss hole where the multiaxial stress field is generated is formed of the short fiber reinforcing material, the impeller can improve the mechanical strength around the boss hole.

The eighth aspect is the impeller of any one of the first to seventh aspects, wherein the short fiber reinforced portion is formed of a composite material containing a resin having a breaking elongation of 4% or more.

According to this aspect, by using a highly ductile resin for the short fiber reinforced portion, the toughness in the direction in which the fiber orientation is small is improved, and as a result, the strength anisotropy is alleviated. Therefore, the short fiber reinforced portion further has mechanical properties corresponding to the multiaxial stress field.

The ninth aspect is the impeller of the eighth aspect in which the short fiber reinforced portion is formed of a composite material containing a resin having a breaking elongation of 8% or more.

According to this aspect, by using a highly ductile resin for the short fiber reinforced portion, the toughness in the direction of less fibrous orientation is improved, and as a result, the strength anisotropy is alleviated. Therefore, the short fiber reinforced portion further has mechanical properties corresponding to the multiaxial stress field.

A tenth aspect is the impeller of any one of the first to ninth aspects, wherein the short fiber reinforcing portion is formed of a composite material containing a resin to which an elastomer is added.

According to this aspect, by using a highly ductile resin for the short fiber reinforced portion, the toughness in the direction of less fibrous orientation is improved, and as a result, the strength anisotropy is alleviated. Therefore, the short fiber reinforced portion further has mechanical properties corresponding to the multiaxial stress field.

The eleventh aspect is an impeller having a front surface, a back surface, and a hub surface, and having a dense portion formed of a dense fiber reinforced material and a foamed portion formed of a foamed fiber reinforced material. , The hub surface side has an impeller surface layer portion having a plurality of blades arranged in the circumferential direction and a boss hole penetrating along the direction from the front surface side to the back surface side, and at least a part of the foam portion. It is an impeller including an inner layer portion of the impeller having the above.

According to this aspect, the impeller has a dense portion formed of a dense fiber reinforced material and a foamed portion formed of a foamed fiber reinforced material. On the other hand, the impeller has a foamed portion in at least a part of the inner layer portion of the impeller.
In the composite material containing the reinforcing fibers, the orientation of the reinforcing fibers is randomized by the foaming of the resin, and the strength anisotropy is alleviated. Therefore, by forming at least a part of the inner layer portion of the impeller, which is a multi-axis stress field, as a foamed portion, the impeller has a material structure having mechanical strength corresponding to the stress state.
Therefore, the inner layer of the impeller can handle stress fields in multiple directions.
Further, by using the foamed portion, the weight of the impeller can be reduced and the inertial force can be reduced.

A twelfth aspect includes an impeller according to any one of the first to eleventh aspects, and a rotation shaft inserted into the boss hole of the impeller and rotating the impeller.

According to this aspect, it is possible to obtain a rotary machine in which the mechanical strength of the inner layer portion of the impeller is improved.

A thirteenth aspect is a method for manufacturing an impeller having a long fiber reinforced portion formed of a long fiber reinforced material and a short fiber reinforced portion formed of a short fiber reinforced material, wherein the impeller mold and a mold are used. The mold and the mold from the back side so that the installation process of installing the pins on the front side, the long fiber reinforced plastic melted on the surface layer, and the short fiber reinforced plastic melted on the inner layer are injected in a two-layer structure. It is a method of manufacturing an impeller which carries out an injection step of injecting the molten long fiber reinforcing material and the molten short fiber reinforcing material toward a pin.

According to this aspect, an impeller having a short fiber reinforcing portion can be formed in at least a part of the inner layer portion of the impeller. Therefore, it is possible to manufacture an impeller in which the inner layer portion of the impeller can cope with a stress field in multiple directions.
Further, an impeller in which the two resins are integrally molded can be manufactured by a sandwich molding method capable of injection molding a material having a two-layer structure of a surface layer and an inner layer. By applying the sandwich molding method, the surface layer part and the inner layer part are integrated in a molten state, so the possibility of a decrease in interface strength can be reduced, and productivity can be improved and manufacturing costs can be reduced by integral molding. Become.

A fourteenth aspect is a method for manufacturing an impeller having a dense portion formed of a dense fiber reinforced material and a foamed portion formed of a foamed fiber reinforced material, wherein the impeller mold and the mold of the impeller The gold from the back side so that the installation process of installing the pin on the front side, the non-foaming fiber reinforced material melted on the surface layer, and the foaming fiber reinforced material melted on the inner layer are injected in a two-layer structure. It is a method of manufacturing an impeller which carries out an injection step of injecting the molten non-foaming fiber reinforcing material and the molten foaming fiber reinforcing material toward a mold and the pin.

According to this aspect, an impeller having a foamed portion in at least a part of the inner layer portion of the impeller can be formed. Therefore, it is possible to manufacture an impeller in which the inner layer portion of the impeller can cope with a stress field in multiple directions.
Further, an impeller in which the two resins are integrally molded can be manufactured by a sandwich molding method capable of injection molding a material having a two-layer structure of a surface layer and an inner layer. By applying the sandwich molding method, the surface layer part and the inner layer part are integrated in a molten state, so the possibility of a decrease in interface strength can be reduced, and productivity can be improved and manufacturing costs can be reduced by integral molding. Become.

According to one aspect of the present invention, the inner layer portion of the impeller can handle stress fields in multiple directions.

It is sectional drawing along the axis of the rotary machine which concerns on 1st Embodiment. It is sectional drawing along the axis of the impeller which concerns on 1st Embodiment. It is sectional drawing in III-III of FIG. It is a graph which shows the volume fraction at each fiber length. It is a graph which shows the cumulative volume fraction at each fiber length. It is a flowchart of the manufacturing method of the impeller which concerns on 1st Embodiment. It is a figure explaining the manufacturing method of the impeller which concerns on 1st Embodiment. It is a perspective view of the molding raw material pellet of the long fiber reinforcing material used in the manufacturing method of the impeller which concerns on 1st Embodiment. It is a perspective view of the molding raw material pellet of the short fiber reinforcing material used in the manufacturing method of the impeller which concerns on 1st Embodiment. It is sectional drawing along the axis of the impeller which concerns on 2nd Embodiment. It is an enlarged view of the XI part of FIG.

Hereinafter, various embodiments according to the present invention will be described with reference to the drawings.

<First Embodiment>
Hereinafter, the turbocharger 1 (rotary machine) according to the first embodiment will be described.
As shown in FIG. 1, the turbocharger 1 includes a rotating shaft 2, a turbine 3 and a compressor 4 that rotate together with the rotating shaft 2, and a housing connecting portion 5 that connects the turbine 3 and the compressor 4 and supports the rotating shaft 2. And.
In the turbocharger 1, the turbine 3 is rotated by the exhaust gas G from the engine (not shown), and the air AR compressed by the compressor 4 is supplied to the engine in accordance with the rotation.

The rotation axis 2 extends along the axis Ax and rotates about the axis Ax.

The turbine 3 is arranged on one side in the direction along the axis Ax (on the right side when facing the paper surface of FIG. 1).
In the following description, unless otherwise specified, the direction along the axis Ax is simply "axial Da", the circumferential direction of the rotating shaft 2 is "circumferential Dc", and the radial direction of the rotating shaft 2 is "radial Dr". ".

The turbine 3 includes a turbine impeller 14 to which a rotating shaft 2 is attached and a turbine blade 15, and a turbine housing 11 that covers the turbine impeller 14 from the outer peripheral side.

The rotating shaft 2 is fitted in the turbine impeller 14. Therefore, the turbine impeller 14 can rotate around the axis Ax together with the rotating shaft 2 around the axis Ax.

The turbine housing 11 covers the turbine impeller 14. The turbine housing 11 extends from the leading edge portion (the end portion outside the radial direction Dr) of the turbine blade 15 toward the outside of the radial direction Dr, and has a ring shape centered on the axis Ax at a position outside the radial direction Dr. The turbine housing 11 is formed with a scroll passage 12 that communicates the inside and outside of the turbine housing 11. When the exhaust gas G is introduced into the turbine impeller 14 from the scroll passage 12, the turbine impeller 14 and the rotating shaft 2 rotate.

Further, the turbine housing 11 is formed with a discharge port 13 that opens on one side of the axis Ax. The exhaust gas G that has passed through the turbine blade 15 flows toward one side of the axial direction Da, and is discharged from the discharge port 13 to the outside of the turbine housing 11.

The compressor 4 is arranged on the other side (left side when facing the paper surface of FIG. 1) in the axial direction Da.
A rotating shaft 2 is attached to the compressor 4. The compressor 4 includes an impeller 24 and a compressor housing 21 that covers the impeller 24 from the outer peripheral side.

The rotating shaft 2 is fitted in the boss hole 27a described later of the impeller 24. Therefore, the impeller 24 can rotate around the axis Ax together with the rotation axis 2 around the axis Ax.

The compressor housing 21 covers the impeller 24. The compressor housing 21 is formed with a suction port 23 that opens on the other side (front side of the impeller 24) in the axial direction Da, and air AR is introduced from the outside of the compressor housing 21 through the suction port 23 to the impeller 24. Introduce to. Then, the rotational force from the turbine impeller 14 is transmitted to the impeller 24 via the rotation shaft 2, so that the impeller 24 rotates around the axis Ax and the air AR is compressed.

The compressor housing 21 extends from the trailing edge of the blade 25 (downstream end of the air AR flow) described later toward the outside of the radial Dr, and has a ring centered on the axis Ax at a position outside the radial Dr. A compressor passage 22 having a shape and communicating with the inside and outside of the compressor housing 21 is formed. The air AR compressed by the impeller 24 is introduced into the compressor passage 22. Therefore, the compressed air AR is discharged to the outside of the compressor housing 21.

The housing connecting portion 5 is arranged between the compressor housing 21 and the turbine housing 11 and connects the compressor housing 21 and the turbine housing 11. Further, the housing connecting portion 5 includes a bearing 6 that covers the rotating shaft 2 from the outer peripheral side. The housing connecting portion 5 is supported by the bearing 6 so that the rotating shaft 2 can rotate relative to the housing connecting portion 5.

(Imeller)
Next, the structure of the impeller 24 will be described in detail with reference to FIGS. 2 to 5.
The impeller 24 includes an impeller surface layer portion 26 that forms a surface layer of the impeller 24 in the radial direction Dr, and an impeller inner layer portion 27 that forms an inner layer of the impeller 24 in the radial direction Dr. The impeller 24 further has a front surface 24a, a back surface 24b, and a hub surface 24c.
The impeller surface layer portion 26 has a plurality of blades 25 arranged in the circumferential direction Dc on the hub surface 24c side.
The impeller inner layer portion 27 has a boss hole 27a extending in the axial direction Da inside the radial direction Dr. The rotating shaft 2 is inserted into the boss hole 27a and fitted.

As shown in FIGS. 2 and 3, the impeller 24 has a composite material portion 50 formed of a composite material.
The composite material portion 50 is formed of a composite material containing a resin and reinforcing fibers.

The resin used for the composite material portion 50 is a thermoplastic resin, and can be solidified by filling a mold described later in a molten state and then cooling the resin. Examples of the thermoplastic resin include polyethersulfone (PES), polyetherimide (PEI), polyetheretherketone (PEEK), polyetherketone (PEK), polyetherketoneketone (PEKK), polyketonesulfide (PKS), and poly. Examples thereof include allyl ether ketone (PAEK), aromatic polyamide (PA), polyamideimide (PAI), and polyimide (PI).

Examples of the reinforcing fibers used in the composite material include carbon fibers, glass fibers, whiskers and the like.

The composite material portion 50 has a long fiber reinforcing portion 51 formed of a long fiber reinforcing material described later, and a short fiber reinforcing portion 52 formed of a short fiber reinforcing material described later. The long fiber reinforcing material is a composite material containing a resin and reinforcing fibers. The short fiber reinforcing material is also a composite material containing a resin and reinforcing fibers.
The composite material portion 50 of the impeller 24 has a short fiber reinforced portion 52 in at least a part of the impeller inner layer portion 27. In the case of this embodiment, all of the impeller inner layer portions 27 are short fiber reinforced portions 52.
On the other hand, the composite material portion 50 other than the short fiber reinforcing portion 52 is the long fiber reinforcing portion 51. That is, at least the composite material portion 50 of the impeller surface layer portion 26 is the long fiber reinforced portion 51. In the case of this embodiment, all of the impeller surface layer portions 26 are long fiber reinforced portions 51.

In the present embodiment, the short fiber reinforced portion 52 is covered with the inner peripheral surface 52a defining the boss hole 27a of the impeller 24 and the long fiber reinforced portion 51, and the inner peripheral surface 51a of the long fiber reinforced portion 51 described later. It has an outer peripheral surface 52b that is in contact with the outer peripheral surface 52b. The inner peripheral surface 52a of the short fiber reinforced portion 52 extends along the axial direction Da. The diameter of the outer peripheral surface 52b of the short fiber reinforced portion 52 gradually changes in the radial direction from the front surface 24a side to the back surface 24b side of the impeller 24. The diameter of the outer peripheral surface 52b of the short fiber reinforced portion 52 increases from the front surface 24a side toward the back surface 24b side, and decreases in the vicinity of the back surface 24b.
A highly ductile resin is used for the short fiber reinforced portion 52. In the present embodiment, a resin having a breaking elongation of 4% or more is used as a highly ductile resin. Desirably, 8% or more of the resin may be used as the highly ductile resin.
As a modification, a resin to which an elastomer is added may be used as a highly ductile resin.

The long fiber reinforced portion 51 includes an inner peripheral surface 51a that covers the outer peripheral surface 52b of the short fiber reinforced portion 52, and an outer peripheral surface 51b that forms the outer shape of the hub surface 24c and the back surface 24b of the impeller 24 including the plurality of blades 25. Have. The inner peripheral surface 51a of the long fiber reinforcing portion 51 has a shape along the outer peripheral surface of the short fiber reinforcing portion 52. The diameter of the outer peripheral surface 51b of the long fiber reinforced portion 51 gradually changes in the radial direction from the front surface 24a side to the back surface 24b side of the impeller 24. The outer peripheral surface 51b of the long fiber reinforced portion 51 has a tapered diameter increasing from the front surface 24a side to the back surface 24b side of the impeller 24, and is connected to the outer edge of the back surface 24b of the impeller 24.
The outer peripheral surface 51b of the long fiber reinforced portion 51 has a shape that further protrudes, and forms a plurality of blades 25. Therefore, the outer peripheral surface 51b of the long fiber reinforced portion 51 forms a plurality of blades 25 and a hub surface 24c that supports the blades 25.

(Long fiber reinforced material and short fiber reinforced material)
The difference between the materials of the long fiber reinforced plastic and the short fiber reinforced plastic will be described.
The long fiber reinforcing material used as the composite material of the long fiber reinforcing portion 51 is a composite material containing statistically longer reinforcing fibers as compared with the short fiber reinforcing material used as the composite material of the short fiber reinforcing portion 52.
The long fiber reinforcing material mainly has a reinforcing fiber having a fiber length of 0.1 m to 5 mm, and the short fiber reinforcing material mainly has a reinforcing fiber having a fiber length of 0.1 mm to 0.5 mm.

As shown in FIG. 4, the reinforcing fibers of the long fiber reinforcing material are distributed so that the volume ratio of the reinforcing fibers having a long fiber length is larger than that of the reinforcing fibers of the short fiber reinforcing material.
The graph of FIG. 4 shows the volume fraction (vertical axis) at each fiber length (horizontal axis) of the reinforcing fibers constituting each reinforcing material. In FIG. 4, each data of the long fiber reinforcing material is shown as "long fiber", and each data of the short fiber reinforcing material is shown as "short fiber".

As shown in FIG. 5, which is the cumulative distribution of FIG. 4, in the long fiber reinforcing material, the cumulative volume fraction (cumulative volume fraction) of the reinforcing fibers having a fiber length of 0.2 mm or less is less than 50%. In addition, it is composed of reinforcing fibers having a fiber length of 1 mm or more and a cumulative volume fraction of fiber length (cumulative volume fraction) of at least 30% or more.
On the other hand, as shown in FIG. 5, the short fiber reinforcing material is composed of reinforcing fibers having a cumulative volume fraction (cumulative volume fraction) of at least 50% or more of the reinforcing fibers having a fiber length of 0.2 mm or less. There is.
The graph of FIG. 5 shows the cumulative volume fraction (vertical axis) of the reinforcing fibers having each fiber length (horizontal axis) or less of the reinforcing fibers constituting each reinforcing material. In FIG. 5, each data of the long fiber reinforcing material is shown as "long fiber", and each data of the short fiber reinforcing material is shown as "short fiber".

(Production method)
Next, a method of manufacturing the impeller 24 will be described with reference to FIGS. 6 to 9.

First, as shown in FIG. 6, the mold DI of the impeller 24 and the pin PIN on the front side are installed (ST01: installation process).

Following the installation process ST01, the long fiber reinforcing material melted in the surface layer MB and the short fiber reinforcing material melted in the inner layer MA are injected in a two-layer structure from the back side toward the mold DI and the pin PIN. As shown in FIG. 7, the long fiber reinforcing material and the short fiber reinforcing material melted in the mold DI are injected and filled, and cooled and solidified in the mold DI (ST02: injection step). In FIG. 7, the back side is the upstream side of the injection direction Din, and the front side is the downstream side of the injection direction Din.

Following the injection step ST02, the solidified structure STR is taken out from the mold DI by dividing the mold DI. Further, the excess portion is removed and the boss hole 27a is penetrated, so that the taken-out structure STR is shaped into the impeller 24 (ST03: shaping step).

In the present embodiment, in the injection step ST02 of the method for manufacturing the impeller 24, the molten long fiber reinforcing material and the molten short fiber reinforcing material are melted around the radial Dr outer side of the molten short fiber reinforcing material. The long fiber reinforcing material is injected in a laminated state. Therefore, even in the die DI, the long fiber reinforcing material is generally laminated around the outer side of the radial Dr of the short fiber reinforcing material.
Further, in the present embodiment, in the injection step ST02 of the method for manufacturing the impeller 24, after the molten long fiber reinforcing material is injected, the short fiber reinforcing material is being injected while the molten long fiber reinforcing material is being injected. Is ejected. Therefore, the long fiber reinforcing material is first filled in the vicinity of the surface of the mold DI and the pin PIN.
Therefore, as shown in FIG. 7, a surface layer MB is formed between the surface of the mold DI or pin PIN and the inner layer MA.

As shown in FIGS. 8 and 9, the molding raw material pellet PL of the long fiber reinforcing material injected into the surface layer MB is longer than the molding raw material pellet PS of the short fiber reinforcing material injected into the inner layer MA. It is included.

As the molding raw material pellet PL of the long fiber reinforcing material, for example, a pellet in which a fiber bundle PLa of carbon fibers of 3 mm to 20 mm and a resin PLb are integrated is used.
As the molding raw material pellet PS of the short fiber reinforcing material, for example, a pellet in which carbon fiber PSa of less than 1 mm is kneaded with resin PSb and dispersed is used.
When carbon fibers PSa of less than 1 mm are kneaded and dispersed pellets are used, the short fiber reinforcing portion 52 of the impeller 24 produced is formed of reinforcing fibers of less than 1 mm.

(Action and effect)
The impeller 24 of the present embodiment has a long fiber reinforcing portion 51 formed of a long fiber reinforcing material and a short fiber reinforcing portion 52 formed of a short fiber reinforcing material. On the other hand, the impeller 24 has a short fiber reinforcing portion 52 in at least a part of the impeller inner layer portion 27.
The strength anisotropy of the composite material containing the reinforcing fibers differs depending on the fiber length. The longer the fiber, the higher the mechanical strength in the orientation direction of the long fiber, and the shorter the fiber, the less the anisotropy of the mechanical strength. Therefore, by shortening at least a part of the impeller inner layer portion 27, which is a multi-axis stress field, the impeller 24 has a material structure having mechanical strength corresponding to the stress state.

For example, it is assumed that the impeller inner layer portion 27 is a long fiber reinforced portion 51. In this case, in the impeller inner layer portion 27, the reinforcing fibers are likely to be oriented in a specific direction.
Composites containing reinforcing fibers generally have high mechanical strength (for example, tensile strength) in the same direction as the reinforcing fibers are oriented, but mechanical strength in a direction orthogonal to the orientation direction of the reinforcing fibers. Is low.
Therefore, when the reinforcing fibers are oriented in a specific direction in the inner layer portion 27 of the impeller, the mechanical strength in the non-oriented direction is weakened. Therefore, if a multiaxial stress field is generated in the impeller inner layer portion 27 due to centrifugal force, the mechanical strength of the impeller inner layer portion 27 may not be ensured.
On the other hand, by shortening at least a part of the impeller inner layer portion 27, the reinforcing fibers are less likely to be oriented in a specific direction and can cope with a stress field in multiple directions, so that the mechanical strength of the impeller inner layer portion 27 is ensured. it can.
Therefore, the impeller inner layer portion 27 can handle stress fields in multiple directions.

Further, in the impeller 24 of the present embodiment, the fiber lengths of the reinforcing fibers are different between the impeller surface layer portion 26 having a high stress in the uniaxial direction and at least a part of the impeller inner layer portion 27 having a multiaxial low stress field. By lengthening the impeller surface layer portion 26 and shortening at least a part of the impeller inner layer portion 27, the impeller 24 has a material structure having mechanical strength according to the stress state.

Further, in the impeller 24 of the present embodiment, the periphery of the boss hole 27a where the multiaxial stress field is generated is formed of a short fiber reinforcing material. Therefore, the impeller 24 can improve the mechanical strength around the boss hole 27a.

Further, in the impeller 24 of the present embodiment, by using a highly ductile resin for the short fiber reinforced portion 52, the toughness in the direction of less fiber orientation is improved, and as a result, the strength anisotropy is further relaxed and the molding is performed. The residual strain generated during the subsequent solidification shrinkage can also be relaxed by the creep deformation of the resin itself. As a result, in the short fiber reinforced portion 52, mechanical properties corresponding to the multiaxial stress field can be obtained.

The method for producing the impeller 24 of the present embodiment can form an impeller having a short fiber reinforced portion 52 in at least a part of the impeller inner layer portion 27. Therefore, it is possible to manufacture an impeller in which the inner layer portion of the impeller can cope with a stress field in multiple directions.
Further, an impeller in which the two resins are integrally molded can be manufactured by a sandwich molding method capable of injection molding a material having a two-layer structure of a surface layer and an inner layer. By applying the sandwich molding method, the surface layer and the inner layer are integrated in a molten state, so that the possibility of a decrease in interfacial strength can be reduced, and the integral molding can improve productivity and reduce manufacturing costs.

<Second embodiment>
Hereinafter, the impeller 124 according to the second embodiment will be described.
The impeller 124 of the present embodiment is basically the same as the impeller 24 of the first embodiment, except that the impeller 124 has a dense portion and a foamed portion.
The impeller 124 of the present embodiment is provided in the turbocharger 1 (rotary machine) in place of the impeller 24 of the first embodiment.

The impeller 124 will be described in detail with reference to FIGS. 10 and 11.
The impeller 124 includes an impeller surface layer portion 26 that forms a surface layer of the impeller 124 in the radial direction Dr, and an impeller inner layer portion 127 that forms an inner layer of the impeller 124 in the radial direction Dr. The impeller 124 further has a front surface 124a, a back surface 124b, and a hub surface 124c.
The impeller inner layer portion 127 has a boss hole 127a extending in the axial direction Da inside the radial direction Dr. The rotating shaft 2 is inserted into the boss hole 127a and fitted.

As shown in FIG. 10, the impeller 124 has a composite material portion 150 formed of a composite material.
The composite material portion 150 is formed of a composite material containing a resin and reinforcing fibers.

The resin used for the composite material portion 150 is a thermoplastic resin, which can be cured by heating with a mold described later. Examples of the thermoplastic resin include polyethersulfone (PES), polyetherimide (PEI), polyetheretherketone (PEEK), polyetherketone (PEK), polyetherketoneketone (PEKK), polyketonesulfide (PKS), and poly. Examples thereof include allyl ether ketone (PAEK), aromatic polyamide (PA), polyamideimide (PAI), and polyimide (PI).

Examples of the reinforcing fibers used in the composite material include carbon fibers, glass fibers, whiskers and the like.

The composite material portion 150 has a dense portion 151 formed of a dense fiber reinforced material and a foamed portion 152 formed of a foamed fiber reinforced material.
The foamed fiber reinforcing material is a composite material containing a resin and reinforcing fibers, and contains many bubbles in the resin. The foamed fiber reinforced material may be a long fiber reinforced material or a short fiber reinforced material.

In FIG. 11, the reinforcing fibers of the foamed portion 152 are shown by FB, and the resin is shown by RG. As shown in FIG. 11, the foamed portion 152 further has a foam BB in the resin RG.

The dense fiber reinforcing material is a composite material containing a resin and reinforcing fibers. In the dense fiber reinforced plastic, the foaming is suppressed as compared with the foamed fiber reinforced plastic, the number of bubbles distributed in the resin is small, and the reinforcing fibers are densely distributed.
The dense fiber reinforcing material in this embodiment is a long fiber reinforcing material.

The composite material portion 150 of the impeller 124 has a foamed portion 152 in at least a part of the impeller inner layer portion 127. In the case of this embodiment, all of the impeller inner layer portions 127 are foamed portions 152.
On the other hand, the composite material portion 150 other than the foamed portion 152 is a dense portion 151. That is, at least the composite material portion 150 of the impeller surface layer portion 26 is a dense portion 151. In the case of this embodiment, all of the impeller surface layer portions 26 are dense portions 151.

The impeller 124 is manufactured by the same method as the impeller 24 of the first embodiment except that the foam BB is provided in the resin RG.
Foam BB can be provided in the resin RG by injecting a foamable composite material in which a foaming agent or liquid nitrogen is dispersed in a molding raw material pellet of the composite material or a molten composite material.
That is, the non-foamable fiber reinforced plastic melted in the surface layer MB is injected from the back surface side toward the mold DI and the pin PIN so that the foamable fiber reinforced plastic melted in the inner layer MA is injected in a two-layer structure. , The molten non-foamable fiber reinforced material and the molten foamable fiber reinforced material are injected.
After that, when solidified in the mold DI, the surface layer MB becomes a dense fiber reinforced material, and the inner layer MA becomes a foamed fiber reinforced material.

In the impeller 124 of the present embodiment, since the impeller inner layer portion 127 has the foam BB, the orientation of the reinforcing fibers in the foamed portion 152 is randomized, and the strength anisotropy is alleviated. Therefore, the foamed portion 152 further has mechanical properties corresponding to a multiaxial stress field.
On the other hand, in the case of the present embodiment, the generation of bubbles BB is suppressed in the impeller surface layer portion 26. Therefore, since the orientation of the long fiber reinforcing material can be maintained, the mechanical strength in the direction in which high stress is generated can be maintained.
Further, by using the foamed portion, the weight of the impeller can be reduced and the inertial force can be reduced.

<Modification example>
The configurations of the long fiber reinforcing material and the short fiber reinforcing material in each embodiment are as described above.
As a modification, the long fiber reinforcing material is a reinforcing fiber having a fiber length of 0.2 mm or less and having a cumulative volume fraction (cumulative volume fraction) of less than 50% and a fiber length of 1 mm or more. It may be composed of reinforcing fibers having a cumulative volume fraction (accumulated volume fraction) of at least 50% or more.
As another modification, the short fiber reinforcing material may be composed of reinforcing fibers having a cumulative volume fraction (cumulative volume fraction) of at least 80% or more of the reinforcing fibers having a fiber length of 0.2 mm or less.
As yet another modification, the long fiber reinforcing material is a reinforcing fiber having a fiber length of 0.2 mm or less and having a cumulative volume ratio (accumulated volume ratio) of less than 50% and a fiber length of 1 mm or more. The short fiber reinforcing material is composed of reinforcing fibers having a cumulative volume ratio (accumulated volume ratio) of at least 50% or more, and the short fiber reinforcing material is a reinforcing fiber (cumulative volume ratio) having a fiber length of 0.2 mm or less. ) It may be composed of reinforcing fibers having a cumulative volume ratio of at least 80% or more.
The statistically longer the fiber length of the long fiber reinforcing material, the higher the mechanical strength in the direction in which the long fiber reinforcing material is oriented. On the other hand, the statistically shorter the fiber length of the short fiber reinforced plastic, the more mechanical properties corresponding to the multiaxial stress field can be obtained.

In each embodiment, the blade 25 and the hub surfaces 24c and 124c use a composite material containing resin and reinforcing fibers, but as a modification, a resin or metal (not containing reinforcing fibers) may be used. The resins used for the blade 25 and the hub surfaces 24c and 124c include polyethersulfone (PES), polyetherimide (PEI), polyetheretherketone (PEEK), polyetherketone (PEK), and polyetherketoneketone (PEKK). ), Polyetherketone sulfide (PKS), polyetheretherketone (PAEK), aromatic polyamide (PA), polyamideimide (PAI), polyimide (PI) and the like.

In the first embodiment, in the impeller 24, all of the impeller inner layer portions 27 are short fiber reinforced portions 52, but even if the impeller 24 has a short fiber reinforced portion 52 in at least a part of the impeller inner layer portion 27. Good. As a modification, of the impeller inner layer portion 27, the peripheral portion of the boss hole 27a may be the long fiber reinforced portion 51, and the other portion may be the short fiber reinforced portion 52.
As another modification, of the impeller inner layer portion 27, the back surface 24b of the impeller 24 may be the long fiber reinforced portion 51, and the other portion may be the short fiber reinforced portion 52. Similarly, in the impeller 24, all of the impeller surface layer portion 26 is a long fiber reinforced portion 51, but as a modification, even if the impeller 24 has a long fiber reinforced portion 51 in at least a part of the impeller surface layer portion 26. Good.

In the second embodiment, in the impeller 124, all of the impeller inner layer portion 127 is the foamed portion 152, but the impeller 124 may have the foamed portion 152 at least a part of the impeller inner layer portion 127.
As a modification, of the impeller inner layer portion 127, the peripheral portion of the boss hole 127a may be the dense portion 151, and the other portion may be the foamed portion 152.
As another modification, of the impeller inner layer portion 127, the back surface 124b of the impeller 124 may be the dense portion 151, and the other portion may be the foamed portion 152.
Similarly, in the impeller 124, all of the impeller surface layer portion 26 is a dense portion 151, but as a modification, at least a part of the impeller surface layer portion 26 may have a dense portion 151.

In each embodiment, as a modification, a highly ductile resin may be used for the foamed portion 152. By using a highly ductile resin for the foamed portion 152, the toughness in the direction of less fiber orientation is improved, and as a result, the strength anisotropy is alleviated, and the residual strain generated during solidification shrinkage after molding is also the resin itself. It can be alleviated by creep deformation. As a result, in the foamed portion 152, mechanical properties corresponding to the multiaxial stress field can be further obtained.
In this modification, a resin having a breaking elongation of 4% or more is used as a highly ductile resin. Desirably, 8% or more of the resin may be used as the highly ductile resin.
As another modification, a resin to which an elastomer is added may be used as a highly ductile resin.

In each embodiment, a thermoplastic resin is used for the composite material portions 50 and 150, but a thermosetting resin may be used as a modification. Examples of the thermosetting resin include phenol resin, epoxy resin, melamine resin, and silicone resin.

Although some embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof shall be included in the scope of the invention described in the claims and the equivalent scope thereof, as well as in the scope and gist of the invention.

For example, in each embodiment, the turbocharger is described as an example of the rotary machine, but the present invention can be applied to a rotary machine other than the turbocharger.

1 Turbocharger 2 Rotating shaft 3 Turbine 4 Compressor 5 Housing connection 6 Bearing 11 Turbine housing 12 Scroll passage 13 Discharge port 14 Turbine impeller 15 Turbine blade 21 Compressor housing 22 Compressor passage 23 Suction port 24 Impeller 24a Front 24b Back 24c Hub surface 25 Blade 26 Impeller surface layer 27 Impeller inner layer 27a Boss hole 50 Composite material 51 Long fiber reinforced 51a Inner peripheral surface 51b Outer peripheral surface 52 Short fiber reinforced portion 52a Inner peripheral surface 52b Outer peripheral surface 124 Impeller 124a Front 124b Back 124c Hub surface 127 Impeller inner layer part 127a Boss hole 150 Composite material part 151 Dense part 152 Foaming part AR Air Ax Axis BB Bubble Da Axial direction Dc Circumferential direction DI Mold Din Injection direction Dr Radial direction FB Reinforcing fiber G Exhaust gas MA Inner layer MB Surface layer PIN pin PL molding raw material pellet PLa fiber bundle PLb resin PS molding raw material pellet PSa carbon fiber PSb resin RG resin STR structure

Claims (4)

An impeller having a front surface, a back surface, and a hub surface, and having a dense portion formed of a dense fiber reinforced material and a foamed portion formed of a foamed fiber reinforced material.
An impeller surface layer portion having a surface layer formed in the radial direction and having a plurality of blades arranged in the circumferential direction on the hub surface side,
An impeller inner layer portion that forms an inner layer in the radial direction, has a boss hole penetrating along the direction from the front surface side to the back surface side, and has the foamed portion at least in part.
Impeller with. The impeller according to claim 1, wherein the foamed portion is a short fiber reinforced material. The impeller according to claim 1, wherein the fiber reinforcing material of the foamed portion is a short fiber reinforcing material, and the fiber reinforcing material of the dense portion is a long fiber reinforcing material. The impeller according to any one of claims 1 to 3 ,
A rotating shaft inserted into the boss hole of the impeller and rotating the impeller,
A rotating machine equipped with.

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