JP2009293417A - Nozzle vane manufacturing method, nozzle vane, variable nozzle mechanism, and turbocharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nozzle vane manufacturing method for manufacturing a nozzle vane excelling in durability and dimensional accuracy at a low cost while improving productivity, and also to provide a nozzle vane having excellent durability and exhibiting desired characteristics, a variable nozzle mechanism, and a turbocharger. <P>SOLUTION: The nozzle vane manufacturing method has: a molding process A for molding a composition containing metal powder and an organic binder to obtain a molding comprising a shaft part and a blade part formed to project at least in one direction perpendicular to an axis from the shaft part, and a center hole formed in at least one end face of the shaft part; a degreasing process B for removing the organic binder from the inside of the molding to obtain a degreased body; a baking process D for baking the degreased body to obtain a sintered body; and a shaft machining process (machining process E) for applying machining including cutting and/or grinding to a portion corresponding to the shaft part of the sintered body by using a portion corresponding to the center hole of the sintered body. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a nozzle vane manufacturing method, a nozzle vane, a variable nozzle mechanism, and a turbocharger.

The turbocharger supplies high-pressure air to the engine by rotating the turbine using the exhaust gas of the engine and driving a compressor provided coaxially with the turbine. As such a turbocharger (particularly, a turbocharger for a diesel engine), a VG (Variable Geometry) turbocharger capable of controlling a supercharging pressure has been widely used in recent years (see, for example, Patent Document 1).

In such a VG turbocharger, for example, as disclosed in Patent Document 1,
A plurality of nozzle vanes are provided along the outer periphery of the turbine, and a nozzle throat (nozzle hole) for supplying exhaust gas toward the turbine is formed between two adjacent nozzle vanes. Then, by rotating each nozzle vane, the opening degree of the nozzle throat is changed, and the flow rate of the exhaust gas to the turbine is changed. Such VG turbocharger, depending on operating conditions of the engine by optimally adjusting the boost pressure can result low-speed torque increase, fuel consumption, the effects such as NO _X reduction.

Here, the nozzle vane according to Patent Document 1 is formed such that a blade-shaped portion protrudes from the nozzle rotation shaft, and is used by rotating around the nozzle rotation shaft.
Conventionally, such a nozzle vane is formed by forming a material corresponding to the nozzle vane by a precision casting method, and cutting and grinding a portion corresponding to the nozzle rotation shaft of the material to finish it precisely. . Further, a center hole is formed in the material after precision casting and before cutting and grinding, and the center hole is used for cutting and grinding.

However, the precision casting method tends to warp the material, and the dimensional accuracy of the obtained material is not so high. For this reason, it is necessary to make a large machining allowance for cutting and grinding, and the machining takes a long time.
In addition, the precision casting method has a relatively high hardness in the portion in contact with the mold, that is, in the vicinity of the surface of the material, but the hardness inside the material is relatively low. Therefore, when cutting or grinding is performed, a relatively low hardness portion of the material is exposed, and as a result, the durability of the nozzle vane is lowered.

Further, when the center hole is formed, the positional deviation (axial deviation) may occur. for that reason,
In this respect as well, a large machining allowance is required at the time of cutting and grinding, which requires a long time for machining. Further, when cutting or grinding is performed using the misaligned center hole, the resulting nozzle vane is displaced in the relative positional relationship between the wing-shaped portion and the nozzle rotation shaft.
Furthermore, a dedicated machine tool for forming the center hole is required, and there is a problem that the equipment cost is increased.

JP 2006-258108 A

An object of the present invention is to improve productivity and to produce a nozzle vane that can be manufactured inexpensively with excellent durability and dimensional accuracy, and has excellent durability and exhibits desired characteristics. It is an object of the present invention to provide a nozzle vane, a variable nozzle mechanism and a turbocharger that can be used.

The above object is achieved by the present invention described below.
The method for producing a nozzle vane according to the present invention comprises forming a composition containing a metal powder and an organic binder, and forming a shaft portion and a blade portion projecting from the shaft portion in at least one direction perpendicular to the axis. And a molding step of obtaining a molded body comprising a center hole formed in at least one end face of the shaft portion;
A degreasing step of removing the organic binder from the molded body to obtain a degreased body;
Firing the degreased body to obtain a sintered body;
A shaft processing step of performing processing including cutting processing and / or grinding processing on a portion corresponding to the shaft portion of the sintered body using a portion corresponding to the center hole of the sintered body. And

According to the present invention as described above, the sintered body (that is, the material for forming the nozzle vanes) has a shape obtained by uniformly shrinking the formed body, that is, a similar shape of the formed body. Such a sintered body can be produced with superior dimensional accuracy as compared with precision casting without causing problems such as warpage, and the center position accuracy of the center hole is extremely excellent. Therefore, by using such a center hole, processing including cutting and / or grinding is performed on the portion corresponding to the shaft portion of the sintered body, so that the processing allowance for the processing is extremely reduced. As a result, the processing time can be shortened. Moreover, the dimensional accuracy of the obtained nozzle vane can be made excellent.

Further, the difference between the hardness near the surface and the internal hardness of the sintered body can be reduced, and the internal hardness of the sintered body can be made extremely high. Therefore, the obtained nozzle vane has extremely high hardness even in the portion subjected to the above processing, and can exhibit excellent durability.
Furthermore, since a dedicated machine tool for forming the center hole is not required, the equipment cost can be reduced. Therefore, the above nozzle vanes can be manufactured at low cost.

In the nozzle vane manufacturing method of the present invention, in the shaft machining step, the machining is preferably performed on a portion other than the end surface of the portion corresponding to the shaft portion of the sintered body.
Thereby, a manufacturing process can be simplified and the time which manufacture requires can be shortened more.
As described above, according to the present invention, the sintered body has a similar shape to the molded body.
The end face of the shaft portion can be formed so as to be very accurately perpendicular to the axis. Further, in the nozzle vane, the dimensional accuracy in the axial direction of the shaft portion does not require so high accuracy. Therefore, it is not necessary to separately process the end face of the shaft portion, and such a process can be omitted.

In the nozzle vane manufacturing method of the present invention, a blade processing step of performing processing including cutting and / or grinding on a portion corresponding to the blade portion of the sintered body after the firing step or after the shaft processing step. It is preferable to have.
Thereby, the dimensional accuracy of a wing | blade part can be improved.
In the nozzle vane manufacturing method of the present invention, the blade portion has a belt-like shape perpendicular to the axis of the shaft portion in plan view, and in the blade processing step, the blade of the sintered body is processed by the processing. It is preferable to adjust the width of the portion corresponding to the portion in plan view.
Thereby, the dimensional accuracy of the width | variety of a wing | blade part (band-like width in planar view) can be made excellent. In addition, since the machining allowance at that time can be reduced, the time required for machining can be shortened while improving the dimensional accuracy.

In the nozzle vane manufacturing method of the present invention, it is preferable that chamfering is performed on an edge portion of the wing portion in the molding step.
Thereby, it is not necessary to perform chamfering separately, and the time required for manufacturing can be further shortened. At this time, as described above, since the machining allowance is small, the chamfered portion can be left after the machining.

In the nozzle vane manufacturing method of the present invention, after the degreasing step and before the firing step, a preliminary process including cutting and / or grinding in a portion corresponding to the blade portion and / or the shaft portion of the degreased body. It is preferable to have a preliminary processing step for performing general processing.
Since the degreased body is relatively soft, it is easy to process. Therefore, by performing such a preliminary processing step, it is possible to further reduce the time required for processing while improving the dimensional accuracy of the nozzle vane obtained.

In the nozzle vane manufacturing method of the present invention, in the molding step, a flat portion is formed on the outer peripheral surface of the shaft portion,
In the shaft machining step, the machining is preferably performed on a portion other than the portion corresponding to the flat portion of the sintered body.
As described above, since the sintered body has a shape similar to that of the molded body, the angle formed by the protruding direction of the wing portion and the flat portion can be defined with high accuracy. The nozzle vane is normally used by fitting a shaft portion having such a flat portion by fitting it into a through hole or a bottomed hole and rotating the through hole or the bottomed hole. In such a nozzle vane, since the opening degree of the nozzle throat (nozzle opening) varies greatly depending on the slight rotation angle, the angle between the protruding direction of the wing part and the flat part should be regulated with high accuracy. Is extremely important.

In the nozzle vane manufacturing method of the present invention, it is preferable that a pair of the flat portions is provided via the axis of the shaft portion.
Thus, the rotation angle of the nozzle vane as described above can be defined with high accuracy, and the position of the axis of the shaft portion can be regulated with high accuracy. Therefore, by using such a nozzle vane, it is possible to provide a variable nozzle mechanism and a turbocharger that can exhibit desired characteristics.

In the nozzle vane manufacturing method of the present invention, it is preferable that the flat portion is for restricting a rotation angle around the axis of the shaft portion by being applied to an abutting surface.
Thereby, the rotation angle of the nozzle vane can be adjusted with high accuracy.
In the nozzle vane manufacturing method of the present invention, it is preferable that the wing portion is provided so as to protrude from one end portion of the shaft portion.
Thereby, since the processing time of a shaft part can be reduced, the time required for manufacturing can be further shortened.

In the nozzle vane manufacturing method of the present invention, it is preferable that the blade portion is provided so as to protrude from the middle of the shaft portion.
Since such a nozzle vane requires processing for each of the pair of shaft portions, the effect of applying the present invention becomes remarkable.
In the manufacturing method of the nozzle vane of this invention, it is preferable to obtain the said molded object by the metal powder injection molding method in the said formation process.
In the injection molding method, the molded body having a complicated and fine shape can be easily formed by selecting a molding die.

The nozzle vane of the present invention is manufactured by the nozzle vane manufacturing method of the present invention.
Thereby, while having the outstanding durability, the nozzle vane which can exhibit a desired characteristic can be provided.
The nozzle vane of the present invention is a nozzle vane comprising a shaft portion and a wing portion formed so as to protrude from the shaft portion in at least one direction perpendicular to the axis line.
The wing part and the shaft part are integrally formed by powder metallurgy,
A center hole is formed in at least one end face of the shaft portion, and the shaft portion is subjected to processing including cutting and / or grinding processing in a portion other than the center hole.
Thereby, while having the outstanding durability, the nozzle vane which can exhibit a desired characteristic can be provided.

In the nozzle vane of the present invention, when the Vickers hardness HV of the surface where the processing including cutting and / or grinding is performed is A, and the Vickers hardness HV of the surface where the processing is not performed is B Furthermore, A is 200 or more, and A / B is 0.6 to 1
It is preferable that
Thereby, the nozzle vane which has the extremely outstanding durability can be provided.

The variable nozzle mechanism of the present invention includes a plurality of nozzle vanes of the present invention.
Thereby, while having the outstanding durability, the variable nozzle mechanism which can exhibit a desired characteristic can be provided.
A turbocharger according to the present invention includes the variable nozzle mechanism according to the present invention.
Accordingly, it is possible to provide a turbocharger that has excellent durability and can exhibit desired characteristics.

The nozzle vane manufacturing method, nozzle vane, variable nozzle mechanism and turbocharger of the present invention will be described in detail below.
<First Embodiment>
First, a first embodiment of the present invention will be described.
FIG. 1 is a longitudinal sectional view showing a turbocharger according to a first embodiment of the present invention. FIG. 2 is a diagram for explaining a variable nozzle mechanism provided in the turbocharger shown in FIG.
The figure seen from the lever plate side, (b) is the AA line sectional view of (a), FIG. 3 is the figure for demonstrating the effect | action of the variable nozzle mechanism shown in FIG. Figure), Figure 4
2 is a side view of the nozzle vane provided in the variable nozzle mechanism shown in FIG. 2 (a view when the blade portion is viewed in plan), FIG. 5 is a front view and a rear view of the nozzle vane shown in FIG. The figure seen from the opposite side to a lever plate, (b) is the figure seen from the lever plate side.

(Turbocharger)
A turbocharger 10 shown in FIG. 1 has a variable capacity turbocharger (VG (Variab).
le Geometry) turbocharger), which has a VG turbine 20 and a compressor 30. A bearing housing 41 is provided between the VG turbine 20 and the compressor 30, and a turbine rotor 43 that is rotatably supported by a bearing 42 is inserted into the bearing housing 41.
The compressor 30 includes a compressor wheel 31 attached to one end side of the turbine rotor 43, and a compressor casing 32 attached to the bearing housing 41 so as to surround and cover the compressor wheel 31.

On the other hand, the VG turbine 20 includes a turbine wheel 21 attached to the other end side of the turbine rotor 43, a turbine casing 22 attached to the bearing housing 41 so as to surround and cover the turbine wheel 21, and the turbine wheel 21. The variable nozzle mechanism 23 changes the flow rate of the exhaust gas (fluid) flowing into the gas, and the drive mechanism 24 drives the variable nozzle mechanism 23.

A scroll 25 is formed inside the turbine casing 22 so as to surround the outer periphery of the turbine wheel 21 along the circumferential direction of the turbine rotor 43. Scroll 25
An exhaust gas inlet (not shown) is provided substantially along the tangential direction of the scroll 25, and an exhaust gas outlet 26 is provided along the rotational axis 44 of the turbine rotor 43.
In such a turbocharger 10, the exhaust gas that has flowed into the scroll 25 from the exhaust gas inlet (not shown) as the driving fluid is variably adjusted by the variable nozzle mechanism 23 and flows into the turbine wheel 21. Is rotated and exhausted from the exhaust gas outlet 26.
On the other hand, the compressor wheel 31 is rotationally driven by the rotation of the turbine wheel 21 and is used, for example, to pump a fluid such as air.

(Variable nozzle mechanism)
Here, the variable nozzle mechanism 23 will be described in detail.
The variable nozzle mechanism 23 rotates a plurality of nozzle vanes 1 provided at equal pitches in the circumferential direction on the inner peripheral side of the scroll 25, a nozzle mount 2 that rotatably supports each nozzle vane 1, and each nozzle vane 1. Drive ring 3, a lever plate 4 that rotates each nozzle vane 1 as the drive ring 3 rotates, a support plate 5, and a plurality of nozzle supports 6.

The plurality of nozzle vanes 1 are arranged between the adjacent nozzle vanes 1 with a scroll 25.
Is arranged so as to form a nozzle throat through which exhaust gas flows into the turbine wheel 21. In the nozzle throat, the opening degree of the flow path changes depending on the rotation angle of the nozzle vane 1.
Each nozzle vane 1 has a shaft portion 11 and a blade portion 12. Each nozzle vane 1
Details of each part will be described later.

The nozzle mount 2 is fixed to the turbine casing 22, and the shaft portion 1 of each nozzle vane 1.
1 is rotatably supported. The nozzle mount 2 is formed with an engaging portion made of, for example, a through hole for rotatably supporting the shaft portion 11.
A support plate 5 is attached to the nozzle mount 2 on the side of the plurality of nozzle vanes 1 via a plurality of nozzle supports 6. Thereby, the wing | blade part 12 of each nozzle vane 1 is arrange | positioned between the nozzle mount 2 and the support plate 5. FIG.

The drive ring 3 has a disk shape and is rotatably supported by the nozzle mount 2.
Further, on the outer peripheral side of the drive ring 3, grooves 3 a that engage with the lever plate 4 (connection pin portion 4 a) are formed at equal intervals in the circumferential direction. Further, the drive ring 3 has a drive groove 3b.
Although not shown, the link of the drive mechanism 24 is engaged with the drive groove 3b.
The drive mechanism 24 has an actuator rod 27 and an actuator 28.
The driving mechanism 24 reciprocates the actuator rod 27 by the operation of the actuator 28, and converts the reciprocating motion into a rotational motion of the drive ring 3 via a link (not shown).

A plurality of lever plates 4 are provided at equal intervals in the circumferential direction corresponding to the plurality of grooves 3 a of the drive ring 3. As shown in FIG. 2B, on the outer peripheral side (one end side) of each lever plate 4, a cylindrical connecting pin portion 4a is formed to project, and each connecting pin portion 4a engages with a corresponding groove 3a. is doing. Moreover, the through-hole 4b is formed in the inner peripheral side (other end side) of each lever plate 4,
The shaft portion 11 of the nozzle vane 1 is fitted in the through hole 4b. Here, the shaft portion 11 is pressed by pressing the outer peripheral surface of the end portion of the shaft portion 11 against the inner wall of the through hole 4b using a center hole 14 described later.
Is fixed to the lever plate 4 by caulking. It should be noted that a bottomed hole may be formed in the lever plate 4 in place of the through hole 4 b as a fitting for the shaft portion 11 of the nozzle vane 1.

In the variable nozzle mechanism 23 configured as described above, when the drive ring 3 is rotated by the drive mechanism 24, the lever plate 4 is rotated around the shaft portion 11 of the nozzle vane 1 via the connecting pin portion 4a. As a result, the nozzle vane 1 rotates around the shaft portion 11, and the blade angle of the nozzle vane 1 (the rotation angle of the blade portion 12) changes.
At this time, the actuator 28 is driven and controlled so that the flow rate of the exhaust gas flowing through the nozzle throat becomes a predetermined flow rate. Specifically, each nozzle vane 1 opens a nozzle throat (nozzle throat) as shown in FIG.
When the exhaust gas flow rate is small, the nozzle throat is controlled to rotate in the closing direction as shown in FIG.
FIG. 2A shows a state where the nozzle throat is closed to the maximum, and FIG. 3 shows a state where the nozzle throat is opened to the maximum.

(Nozzle vane)
Here, the detail of each nozzle vane 1 is explained in full detail.
As described above, each nozzle vane 1 has the shaft portion 11 and the wing portion 12.
As shown in FIG. 4 and FIG. 5, the shaft portion 11 has a circular shape with the axis 13 as the center axis in the cross-sectional shape of the main portion. The shaft portion 11 has a wing portion 12 side (left side in FIG. 4) portion rotatably supported by the nozzle mount 2, and a portion opposite to the wing portion 12 (right side in FIG. 4) is a lever. It is fixed to the plate 4.

A center hole 14 is formed in one end surface of the shaft portion 11 (the right end surface in FIG. 4). The center hole 14 is formed so that the cross-sectional shape thereof is circular and the center thereof coincides with the axis 13. In the present embodiment, the center hole 14 has a portion where the cross-sectional area gradually decreases from the opening side toward the bottom surface side, and a portion where the cross-sectional area is constant.
As will be described later, the center hole 14 is formed by a powder metallurgy method, and is engaged with a center of a machine tool (processing device) such as a lathe in the shaft machining step and the blade machining step in the nozzle vane 1 manufacturing process. Used. The center hole 14 is used for caulking and fixing the shaft portion 11 of the nozzle vane 1 in the through hole 4b of the lever plate 4 described above.

In addition, a pair of flat portions 15 (two-surface cut portions) facing each other through the axis line 13 are provided on the outer peripheral surface on one end side (right side in FIG. 4) of the shaft portion 11 (FIG. 5 ( b)).
Although not shown, each of such flat portions 15 is used by being applied to a contact surface (a flat portion formed on the side surface of the through hole 4b) formed on the lever plate 4 described above. Thereby, in the variable nozzle mechanism 23, the rotation angle around the axis 13 of the shaft portion 11 is restricted.
That is, the rotation of the nozzle vane 1 around the shaft portion 11 with respect to the lever plate 4 is restricted (fixed). Therefore, the rotation angle around the shaft portion 11 of the nozzle vane 1 can be adjusted with high accuracy.

In the present embodiment, the pair of flat portions 15 are formed so as to be substantially parallel to each other. In addition, the distance between one flat portion 15 and the axis 13 is equal to the distance between the other flat portion 15 and the axis 13. Each flat portion 15 is formed to be inclined at an angle θ with respect to the protruding direction (blade surface) of the wing portion 12.
In this way, by providing the pair of flat portions 15 via the axis 13 of the shaft portion 11, the rotation angle of the nozzle vane 1 as described above is defined with high accuracy, and the axis 13 of the shaft portion 11 is defined.
Can be regulated with high accuracy. Therefore, by using such a nozzle vane 1, it is possible to provide the variable nozzle mechanism 23 and the turbocharger 10 that can exhibit desired characteristics.

On the other hand, a wing portion 12 is provided at the other end portion (left end portion in FIG. 4) of the shaft portion 11. That is, the wing part 12 is provided so as to protrude from one end part of the shaft part 11.
In the present embodiment, a flange portion 16 that protrudes outside the shaft portion 11 is formed at the other end portion of the shaft portion 11.
As shown in FIG. 4, the wing portion 12 has a band shape extending in a direction perpendicular to the axis 13 of the shaft portion 11 in a plan view. Moreover, the protrusion length of the wing | blade part 12 from the axial part 11 is one end side (
The lower side in FIG. 4 is longer than the other end side (upper side in FIG. 4).

Further, chamfers 17 and 18 are applied to the edge portions at both ends in the width direction (left-right direction in FIG. 4) in plan view of the wing portion 12.
Further, as shown in FIGS. 5A and 5B, the wing portion 12 is slightly curved in the thickness direction. Further, the thickness of the wing portion 12 is gradually reduced toward each end in the extending direction (projecting direction).

In each nozzle vane 1 configured as described above, the shaft portion 11 and the blade portion 12 are integrally formed by a powder metallurgy method, and the shaft portion 11 is cut into a portion other than the center hole 14 as described later. Processing including processing and / or grinding is performed. In this embodiment,
The above-described processing is performed on the end surface of the shaft portion 11 (including the center hole 14) and the portions excluding the flat portions 15.

Each nozzle vane 1 has excellent dimensional accuracy as compared with that obtained by precision casting. In particular, the center hole 14 is formed with high accuracy by a powder metallurgy method, and the outer peripheral surface of the shaft portion 11 is high due to the processing including cutting and / or grinding using the center hole 14. It is finished with precision. Therefore, the relative positional relationship between the shaft portion 11 and the wing portion 12 is formed with high accuracy. As a result, each nozzle vane 1 has excellent dimensional accuracy.

In addition, each nozzle vane 1 is substantially equal to the outer peripheral surface (unprocessed portion) of the wing portion 12 even in the portion subjected to the above processing (for example, the portion other than each flat portion 15 in the outer peripheral surface of the shaft portion 11). It has an extremely high hardness and excellent durability (wear resistance).
More specifically, the surface of a part subjected to processing including cutting and / or grinding (
For example, the Vickers hardness HV of the outer peripheral surface of the shaft portion 11 other than each flat portion 15) is A, and the Vickers hardness H of the surface of the portion not subjected to the processing (for example, the surface of the wing portion 12).
When V is B, A is preferably 200 or more and A / B is preferably 0.6 to 1. In this case, A is more preferably 200 to 350, further preferably 220 to 320, and A / B is more preferably 0.8 to 1,
More preferably, it is 5-1. Thereby, the nozzle vane 1 having extremely excellent durability can be provided.
In this way, each nozzle vane 1 has excellent durability and can exhibit desired characteristics. The variable nozzle mechanism 23 and the turbocharger 10 including a plurality of such nozzle vanes 1 also have excellent durability and can exhibit desired characteristics.

(Nozzle vane manufacturing method)
Next, the manufacturing method of the nozzle vane 1 of the present invention will be described taking the manufacturing method of the nozzle vane 1 configured as described above as an example.
FIG. 6 is a process diagram for explaining the nozzle vane manufacturing method of the present invention, and FIGS. 7 and 8 are views (side views) for explaining the nozzle vane manufacturing method shown in FIG.
As shown in FIG. 6, the manufacturing method of the nozzle vane 1 includes: [1A] a molding process for manufacturing a molded body, [1B] a degreasing process for performing a degreasing process, [1C] a preliminary processing process for performing preliminary processing, and [ 1
D] a firing process for performing firing, and [1E] a machining process for performing the main machining (including a shaft machining process and a blade machining process).

Hereafter, each process is demonstrated in detail in order of a process.
[1A] Molding process <1A1>
First, a metal powder and an organic binder are prepared and kneaded with a kneader to obtain a kneaded product (composition) (composition preparation step).

In this kneaded material (compound), the metal powder is uniformly dispersed.
The metal powder and the organic binder are preferably those that do not chemically react with each other.
Examples of metal materials constituting such metal powder include stainless steel, die steel,
Various Fe-based alloys such as high speed tool steel, low carbon steel, Fe-Ni alloy, Fe-Ni-Co alloy,
Various Ni type alloys, various Cr type alloys, etc. are mentioned.

Among these, as the metal powder, those containing an Fe-based alloy as a main material are preferable, and those containing stainless steel as a main material are more preferable. Such an Fe-based alloy can have various characteristics depending on the carbon content. Therefore, by using a metal powder whose main material is an Fe-based alloy, the sintered body 50C obtained in the step [1D] described later can have characteristics suitable for the nozzle vane 1.

Specific examples of stainless steel include SUS304, SUS310, SUS316, and SUS.
317, SUS329, SUS410, SUS430, SUS440, SUS630, and the like, and heat-resistant steel with an increased carbon content is also used.
Two or more kinds of metal powders having different compositions may be mixed and used. In this case, the sintered body 50C obtained in step [1D] to be described later can have an alloy composition that cannot be manufactured by conventional casting.

The average particle size of the metal powder is not particularly limited, but is preferably 1 to 100 μm, and more preferably 1 to 6 μm.
In particular, by using a fine powder having an average particle size of 6 μm or less as the metal powder, the grain size of the crystal structure of the sintered body 50C obtained in the step [1D] described later (hereinafter referred to as “crystal grain size”). Can be significantly reduced.

Here, it is empirically known that the mechanical strength of metal increases in inverse proportion to the 1/2 power of the crystal grain size. That is, by reducing the crystal grain size, the mechanical strength of the metal can be dramatically increased. This is because the growth of cracks is suppressed in an aggregate of fine crystal structures,
This is probably because the probability of destruction decreases. Therefore, the sintered body obtained by using a fine powder having an average particle size of 6 μm or less as the metal powder has excellent mechanical strength.

Furthermore, it is particularly preferable to use a metal powder having a specific surface area of 200 m ² / kg or more.
It is more preferable to use a metal powder of about 00 to 900 m ² / kg. As described above, the metal powder having a large specific surface area has high surface activity (surface energy), and can be easily sintered even when applied with lower energy. Therefore, in the firing step [1D] described below,
The degreased body 50B can be sintered in a shorter time.

Further, the metal powder may be produced by, for example, an atomizing method (for example, a water atomizing method, a gas atomizing method, a high-speed rotating water atomizing method, etc.), a reduction method, a carbonyl method, or a pulverization method. It is preferable to use those produced by
According to the atomizing method, extremely fine metal powder can be produced efficiently.
In addition, the metal powder produced by the atomization method has a spherical shape that is relatively close to a true sphere, so it has excellent dispersibility and fluidity. Can also be increased.

Examples of the organic binder include polyolefins such as polyethylene, polypropylene, and ethylene-vinyl acetate copolymer, acrylic resins such as polymethyl methacrylate and polybutyl methacrylate, styrene resins such as polystyrene, polyvinyl chloride, and polyvinylidene chloride. Various resins such as polyesters such as polyamide, polyethylene terephthalate, polybutylene terephthalate, polyethers, polyvinyl alcohol, or copolymers thereof, various waxes, paraffins, higher fatty acids (eg stearic acid), higher alcohols, higher fatty acid esters Higher fatty acid amides, etc., and one or more of these can be used in combination.

Among these, as the organic binder, those containing polyolefin as a main component are preferable.
Polyolefin has a relatively high decomposability with a reducing gas. For this reason, when polyolefin is used as the main component of the organic binder, the molded body 50A is formed in the step [1B] described later.
Can be reliably degreased in a shorter time.
Further, the content of the organic binder is preferably about 2 to 20 wt%, more preferably about 5 to 10 wt% of the entire kneaded product. When the content of the organic binder is within the above range, the molded body 50A can be formed with good moldability in the step <1A2> to be described later, the density is increased, and the stability of the shape of the molded body 50A is particularly improved. It can be excellent. Thereby, the difference in size between the molded body 50A and the degreased body 50B, the so-called shrinkage rate, can be reduced. As a result, the dimensional accuracy of the degreased body 50B and the sintered body 50C can be improved. Therefore, the position accuracy of the center hole 14 of the sintered body 50C obtained in the process [1D] described later can be made extremely excellent.

A plasticizer may be added to the kneaded product. Examples of the plasticizer include phthalic acid esters (eg, DOP, DEP, DBP), adipic acid esters, trimellitic acid esters, sebacic acid esters, and the like, and one or more of these are mixed. Can be used.
Furthermore, in addition to the metal powder, the organic binder, and the plasticizer, various additives such as an antioxidant, a degreasing accelerator, and a surfactant can be added to the kneaded material as necessary.

The kneading conditions vary depending on various conditions such as the metal composition and particle size of the metal powder to be used, the composition of the organic binder, and the blending amount thereof. For example, kneading temperature: about 50 to 200 ° C., kneading time: It can be about 15 to 210 minutes.
Further, the kneaded product is formed into pellets (small lumps) as necessary. The particle size of the pellet is, for example, about 1 to 15 mm.

<1A2>
Next, the kneaded product obtained in the above step <1A1> is molded, and as shown in FIG.
A compact 50A is manufactured.
This molded body 50A has the same shape (similar shape) as the sintered body 50C obtained in step [1D] described later. More specifically, the molded body 50A includes a shaft portion 51A and a blade portion 52A formed so as to protrude from the shaft portion 51A in a direction perpendicular to the axis 13 thereof. Here, although there is a difference in machining allowance, the shaft portion 51A has substantially the same shape as the shaft portion 11 of the nozzle vane 1, the blade portion 52A has substantially the same shape as the blade portion 12 of the nozzle vane 1, and the molded body 50A. Is
It has almost the same shape as the nozzle vane 1. Therefore, the center hole 54 is formed in the end surface of the shaft portion 51A.
A is formed, and a pair of flat portions 55A is formed on the outer peripheral surface of the shaft portion 51A.

Further, chamfers 57A and 58A are provided on the edge of the wing portion 52A. Thereby, it is not necessary to perform chamfering separately in the subsequent processing step [1E] and the time required for manufacturing can be further shortened.
The production method (molding method) of the molded body 50A is not particularly limited, and examples thereof include a metal powder injection molding (MIM: Metal Injection Molding) method, a compression molding (compact molding) method, and an extrusion molding method. Among these, the metal powder injection molding method is preferable.
With this MIM method, a compact 50A compact and finely shaped molded body 50A can be manufactured with a near net (shape close to the final shape), and the characteristics of the metal powder used can be fully utilized. Has the advantage.

Hereinafter, as an example of the molding method, manufacturing of the molded body 50A by the MIM method will be described.
First, by using the kneaded product obtained in the above step <1A1> or pellets granulated from the kneaded product, injection molding is performed by an injection molding machine to manufacture a molded body 50A having a desired shape and size. In this case, it is possible to easily manufacture a molded body 50A having a complicated shape by selecting a molding die.

The molded body 50A thus obtained is in a state where the metal powder is almost uniformly dispersed in the organic binder.
In addition, the shape and size of the molded body 50A to be manufactured are the same as those of the molded body 50 obtained by subsequent degreasing and sintering.
It is determined in anticipation of the contraction of A.
The molding conditions for injection molding differ depending on various conditions such as the metal composition and particle size of the metal powder to be used, the composition of the organic binder, and the amount of these blended, but for example, the material temperature is:
Preferably about 80-200 ° C., the injection pressure is preferably 2-30 MPa (20-300
kgf / cm ² ).

[1B] Degreasing Step Degreasing treatment (debinding treatment) is performed on the molded body 50A obtained in the above step [1A] to obtain a degreased body 50B as shown in FIG.
Here, the degreased body 50B has the same shape (similar shape) as the molded body 50A. More specifically, the degreased body 50B includes a shaft portion 51B and a wing portion 52B formed so as to protrude from the shaft portion 51B in a direction perpendicular to the axis 13 thereof. A center hole 54B is formed on the end surface of the shaft portion 51B, and a pair of flat portions 55B is formed on the outer peripheral surface of the shaft portion 51B. Further, chamfers 57B and 58B are formed at the edge of the wing 52B.

The degreasing treatment for the molded body 50A may be performed in any atmosphere of an oxidizing atmosphere, an inert atmosphere, a reduced pressure atmosphere, and a reducing atmosphere, but is preferably performed in a reducing atmosphere. Thereby, the organic binder in the molded body 50A can be quickly decomposed and removed from the molded body 50A. Thereby, the residual amount of the organic binder in the degreased body 50B obtained can be suppressed very small. As a result, a sintered body 50C having a low carbon content can be obtained in the firing step [1D] described later. Moreover, there exists an advantage of preventing reliably the oxidation of the metal powder contained in 50A of molded objects by performing a degreasing process in reducing environment.

As the reducing gas contained in the reducing atmosphere, for example, a mixed gas such as ammonia decomposition gas can be used in addition to a gas such as hydrogen and carbon monoxide. Of these, the reducing gas is preferably hydrogen gas. Since hydrogen gas has a strong reducing action, the organic binder in the molded body 50A can be decomposed more quickly. For this reason, the degreasing process with respect to 50 A of compacts can be performed more rapidly and fully, and the sintered compact 5 obtained by process [1D] mentioned later
An increase in the amount of carbon in 0C can be reliably prevented.

In addition, since the hydrogen molecules constituting the hydrogen gas have a very small molecular size, the compact 5
It can easily enter the gap in 0A. For this reason, according to hydrogen gas, the compact 50
The organic binder present in A can also be easily decomposed and removed, and an increase in the amount of carbon can be reliably prevented not only in the surface layer portion but also in the central portion of the sintered body 50C. As a result, it is possible to reliably prevent an increase in the amount of carbon in the portion exposed on the surface after processing of the sintered body 50C in the processing step [1E] described later.

Furthermore, since hydrogen gas has a very high thermal conductivity, the heat generated from the heating source is transferred to the compact 50.
While being efficiently transmitted to A, the heated molded body 50A can be efficiently radiated. As a result, there is an advantage that the molded body 50A can be efficiently heated and cooled in the degreasing step.
Here, the reducing atmosphere may be composed of only a reducing gas, but when it contains other gases, it preferably contains an inert gas such as nitrogen, helium, or argon. These inert gases prevent the decomposition action of the organic binder by the reducing gas, and increase the safety of the reducing atmosphere, so that the handling thereof can be facilitated.

In this case, the concentration of the reducing gas contained in the reducing atmosphere is not particularly limited, but is 50 vol.
% Or more is preferable, and 70 vol% or more is more preferable. Thereby, the decomposition | disassembly effect | action of the organic binder by reducing gas is fully exhibited, ensuring the safety | security of a reducing atmosphere.
For example, in the case of ammonia decomposition gas, the component is a mixed gas of hydrogen gas and nitrogen gas, and the concentration of hydrogen gas (reducing gas) is 75 vol%.

In the degreasing treatment, the temperature (heating temperature) when heating the molded body 50A is slightly different depending on the decomposition start temperature of the organic binder, etc., but is preferably about 100 to 750 ° C., and about 150 to 600 ° C. More preferably. Thereby, the decomposition | disassembly effect | action of the organic binder by reducing gas is fully exhibited, and 50 A of molded objects can be degreased | fastened sufficiently.

Further, the time for heating the molded body 50A (heating time) varies slightly depending on the volume of the molded body 50A, etc., but when the heating temperature is within the above range, it is preferably about 0.1 to 20 hours. More preferably, it is about 0.5 to 15 hours. Thereby, degreasing | defatting of the molded object 50A can be performed sufficiently and sufficiently.
Furthermore, it is preferable that the average heating rate at the time of heating 50 A of molded objects is about 1-10 degree-C / min.

By the way, such a degreasing process is performed in a plurality of steps (steps) having different degreasing conditions, so that the organic binder in the molded body 50A is more quickly and molded.
It can be decomposed and removed so as not to remain in A.
The number of processes is not particularly limited, but in the present embodiment, a case where there are two processes will be described as a representative.

In the present embodiment, the degreasing step includes a first degreasing process in which a part of the organic binder is removed from the molded body 50A, and a remaining part of the organic binder in the molded body 50A that has undergone the first degreasing process. 2 degreasing processes. Thus, the organic binder can be gradually removed by removing the organic binder through a plurality of steps. Thereby, degreasing can be uniformly performed without the progress of degreasing being biased to a part of the molded body 50A.

By the way, in the first degreasing process among the above processes, the organic binder may be removed by any method as long as it is a method of removing a part of the organic binder from the molded body 50A.
Specific methods include, for example, a method of heating the molded body 50A, a method of bringing the molded body 50A into contact with a solvent that dissolves the organic binder, and the like.

When heating 50 A of molded objects, it is preferable that the heating temperature is about 150-350 degreeC. By heating the molded body 50A at such a relatively low temperature, it is possible to prevent the entire organic binder in the molded body 50A from being rapidly decomposed and vaporized. Thereby, when the vaporized organic binder is discharged to the outside of the molded body 50A, the molded body 50A is deformed, and as a result, it is possible to prevent the shape retention of the molded body 50A from being lowered.

Further, examples of the heating atmosphere of the molded body 50A include an oxidizing atmosphere, an inert atmosphere, a reducing atmosphere, a reduced pressure atmosphere, and the like, and a reduced pressure atmosphere is particularly preferable. Thereby, removal of the component which is comparatively easy to volatilize in the molded body 50 </ b> A can be preferentially performed by the action of the decompressed atmosphere. For this reason, the organic binder in 50 A of molded objects can be removed in steps, and the shape-retaining property of 50 A of molded objects can be improved more.

In addition, in the molded body 50A that has undergone the first degreasing process in such a reduced-pressure atmosphere, voids are formed by removing easily volatile components. Since the pores communicate with the outside of the molded body 50A, in the second degreasing process described in detail later, the decomposition product of the organic binder can be removed from the molded body 50A through the pores. . Thereby, a degreasing process can be reliably performed to the center part of 50 A of molded objects.
The pressure of such a reduced-pressure atmosphere is not particularly limited, but is 1 × 10 ⁻¹ to 1 × 10 ⁻⁵ [
Pa] degree is preferable, and about 1 × 10 ⁻² to 1 × 10 ⁻⁴ [Pa] is more preferable. Thereby, the above-mentioned actions and effects become more prominent.

On the other hand, in the second degreasing process, the remaining part of the organic binder is removed by heating the molded body 50A that has undergone the first degreasing process in a reducing atmosphere.
The heating temperature of the molded body 50A is preferably about 400 to 600 ° C. This
Without sintering the molded body 50A, the decomposition action of the organic binder by the reducing gas is sufficiently exerted, and the molded body 50A can be reliably degreased.

In the second degreasing process, as described above, the organic binder is removed through the pores formed in the molded body 50A. At this time, the reducing gas penetrates into the pores and promotes the decomposition of the organic binder, but the inner diameter of the pores is very small, so depending on the type of reducing gas, it is difficult to penetrate into the pores. There is also. However, by using hydrogen gas as the reducing gas, the reducing gas can easily enter such small holes. Further, since the metal powder used in the above-described step <1A1> has a very small average particle diameter of 6 μm or less, it is considered that the inner diameter of the above-mentioned pores is further reduced. Even hydrogen gas can easily enter.

In this way, the organic binder is removed to obtain a degreased body 50B as shown in FIG.
The degreased body 50B is suitable for obtaining a sintered body 50C whose carbon content more accurately reflects the carbon content of the metal powder. That is, the difference between the carbon content of the degreased body 50B and the carbon content of the metal powder used in the above-described step <1A1> can be further reduced.

[1C] Preliminary processing step Next, preliminary processing including a cutting step and / or a grinding step is performed on the shaft portion 51B and / or the blade portion 52B of the degreased body 50B as necessary.
Since the degreased body 50B is relatively soft, it is easy to process. Therefore, by performing such a preliminary processing step after the degreasing step [1B] and before the firing step [1D], the dimensional accuracy of the nozzle vane 1 finally obtained is excellent, and the time required for processing Can be further shortened.
The processing in this step can be performed in the same manner as the processing in the processing step [1E] described later.

[1D] Firing step The degreased body 50B obtained in the above step [1B] (or the pre-processed degreased body 50B obtained in the above step [1D]) is fired and sintered in a firing furnace. As shown in FIG.
A sintered body 50C is manufactured.
Here, the sintered body 50C has the same shape (similar shape) as the degreased body 50B. More specifically, the sintered body 50C includes a shaft portion 51C and a blade portion 52C formed so as to protrude from the shaft portion 51C in a direction perpendicular to the axis 13 thereof. A center hole 54C is formed on the end surface of the shaft portion 51C, and a pair of flat portions 55C is formed on the outer peripheral surface of the shaft portion 51C. Further, chamfers 57C and 58C are formed at the edge of the wing portion 52C. Here, the center hole 54 </ b> C constitutes the center hole 14 of the nozzle vane 1.

By this sintering, the metal powder diffuses at the interface between the particles, grows, and becomes a crystal structure. As a result, an overall dense sintered body 50C having a low porosity and a high density can be obtained.
The firing temperature is not particularly limited, but is preferably about 1000 to 1350 ° C.
More preferably, it is about 000-1200 degreeC, and it is still more preferable that it is about 1000-1100 degreeC. By firing the degreased body 50B at such a temperature, it is possible to prevent the crystal structure from becoming larger than necessary. As a result, a sintered body 50C having a fine crystal structure and excellent mechanical properties and chemical properties is obtained.

In addition, since sintering will become inadequate in whole or part when a calcination temperature is less than the said lower limit, there exists a possibility that the mechanical characteristics and surface roughness of 50 C of sintered bodies obtained may fall. On the other hand, if the firing temperature exceeds the upper limit, sintering proceeds more than necessary, the crystal structure becomes enlarged, and the mechanical properties of the resulting sintered body 50C may be reduced.
Further, the firing time is preferably about 0.2 to 7 hours, more preferably about 1 to 4 hours, when the firing temperature is within the above range. By performing firing for such a time at a firing temperature in the above temperature range, sintering of the degreased body 50B can be more reliably optimized and sintered while reliably preventing the enlargement of the crystal structure. As a result, an extremely fine crystal structure can be obtained.

The atmosphere during firing is not particularly limited, but a reducing atmosphere such as hydrogen or carbon monoxide,
Examples thereof include an inert atmosphere such as nitrogen, helium, and argon, and a reduced pressure atmosphere obtained by reducing the pressure of each atmosphere.
In such a sintered body 50C, the carbon content reflects the carbon content of the metal powder more faithfully.

In addition, when the ratio of the increase / decrease amount of the carbon content of the sintered body with respect to the carbon content of the metal powder is calculated, the smaller this ratio (hereinafter, also referred to as “increase / decrease rate”) is the raw material. A stronger correlation will be recognized between the carbon content of the metal powder and the carbon content of the sintered body as the final form. And the stronger this correlation is, the easier it is to bring the carbon content of the sintered body 50C closer to the target value by setting the carbon content of the metal powder to a predetermined value.

From this viewpoint, the rate of increase / decrease is preferably 50% or less, and more preferably 30% or less. If the increase / decrease rate is within the above range, a strong correlation will be recognized between the carbon content of the metal powder and the carbon content of the sintered body 50C, and by setting the carbon content of the metal powder, The carbon content of the sintered body 50C can be easily adjusted.
As described above, the sintered body 50C can be obtained.

[1E] Processing Step Next, processing (main processing) including cutting and / or grinding is performed on the sintered body 50C obtained in the above step [1D] to form the nozzle vane 1.
In the present embodiment, the processing step [1E] is a first step in which processing including cutting and / or grinding is performed on the end surfaces of the shaft portion 51C of the <1E1> sintered body 50C and the shaft portion 51C of the blade portion 52C.
And the blade portion 52C of the <1E2> sintered body 50C (the blade portion 52D after the step <1E1>).
A second process is performed in which the end surface opposite to the shaft portion 51C is subjected to processing including cutting and / or grinding.
It has the following processing steps.
That is, in this step [1E], the shaft portion 51C of the sintered body 50C is subjected to processing including cutting and / or grinding, and the blade portion 52C (wing portion 52D) of the sintered body 50C is cut. And a blade processing step for performing processing including processing and / or grinding.

Hereinafter, the first processing step <1E1> and the second processing step <1E2> will be sequentially described in detail.
<1E1> First Processing Step In the processing step [1E], first, the axis of the sintered body 50C (material) obtained using the steps [1A] to [1D] (that is, the powder metallurgy method) as described above. Shaft portion 5 of portion 51C and wing portion 52C
Processing including cutting and / or grinding is performed on the end surface on the 1C side to obtain an intermediate workpiece 50D as shown in FIG.
Here, the intermediate workpiece 50D includes a shaft portion 11 and a wing portion 52D formed so as to protrude from the shaft portion 11 in a direction perpendicular to the axis 13 thereof. A center hole 14 is formed on the end surface of the shaft portion 11, and a pair of flat portions 15 is formed on the outer peripheral surface of the shaft portion 11. Further, chamfers 57C and 18 are formed at the edge of the wing 52D.

(Shaft machining process)
In this step <1E1>, when the shaft portion 11 is formed (shaft machining step), a portion other than the pair of flat portions 55C on the outer peripheral surface of the shaft portion 51C (the portion corresponding to the shaft portion 51A of the molded body 50A) is formed. Shaft portion 1 having a desired outer diameter and an axial position by performing cutting and / or grinding.
1 is formed.

In particular, in the processing of this step <1E1>, the center hole 14 (the center hole 1 of the molded body 50A) is processed.
4A). That is, at the time of cutting and / or grinding in this step <1E1>, the sintered body 50C is held in a state where the center of a machine tool such as a lathe used for the processing is engaged with the center hole 14.
According to the present invention, the sintered body 50C (that is, the material for forming the nozzle vane 1)
The molded body 50A is uniformly contracted, that is, a similar shape to the molded body 50A. Such a sintered body 50C can be manufactured with superior dimensional accuracy as compared to precision casting without causing problems such as warpage, and the center position accuracy of the center hole 14 is extremely excellent. Become. For example, the accuracy between a pair of flat portions (cut width) of the material is about ± 0.1 mm when manufactured by precision casting, but can be about ± 0.03 mm in the present invention. This satisfies the required accuracy of the finished product ± 0.04 mm. Further, no burrs are generated as in a cold progressive press.

Therefore, by using such a center hole 14 to perform processing including cutting and / or grinding on the shaft portion 51C of the sintered body 50C, the processing allowance for the processing is extremely reduced, and as a result. The processing time can be shortened. Moreover, the dimensional accuracy of the obtained nozzle vane 1 can be made excellent.
Further, as described above, the wing portion 12 is provided so as to protrude from one end portion of the shaft portion 11. That is, the nozzle vane 1 of this embodiment is a single-axis type nozzle vane. Therefore, in the shaft machining step, the machining time of the shaft portion 11 can be reduced as compared with the double-shaft type nozzle vane, so that the time required for manufacturing can be further shortened.

In addition, the difference between the hardness near the surface and the internal hardness of the sintered body 50C can be made small, and the internal hardness of the sintered body 50C can be made extremely high. Therefore, the obtained nozzle vane 1 has an extremely high hardness even in a portion subjected to the above processing, and can exhibit excellent durability.
Further, the center hole 14 is based on the center hole 54A formed in the molding process [1A], and a dedicated machine tool for forming the center hole 14 is not required, so that the equipment cost can be reduced. can do. Therefore, the nozzle vane 1 having excellent durability and dimensional accuracy as described above can be manufactured at low cost.

The machine tool (processing apparatus) used for such processing is not particularly limited as long as it performs cutting and / or grinding using the center hole 14 as described above, and uses various machine tools (for example, a lathe). be able to.
Further, in the shaft machining step, the machining is performed on a portion other than the end face of the shaft portion 51C of the sintered body 50C. Thereby, a manufacturing process can be simplified and the time which manufacture requires can be shortened more.
As described above, according to the present invention, since the sintered body 50C has a similar shape to the molded body 50A, the end face of the shaft portion 51C is formed to be very accurately perpendicular to the axis 13. be able to. In the nozzle vane 1, the dimensional accuracy of the shaft portion 11 in the direction of the axis 13 does not require so high accuracy. Therefore, it is not necessary to separately process the end face of the shaft portion 51C, and such a process can be omitted.

In the shaft machining step, the machining is performed on a portion other than the portion corresponding to the flat portion 55C of the sintered body 50C. As described above, since the sintered body 50C has a shape similar to that of the molded body 50A, the angle θ between the protruding direction of the blade portion 52C and each flat portion 55C can be defined with high accuracy. The nozzle vane 1 is used by fitting a shaft portion 11 having a flat portion 15 by fitting it into a through hole or a bottomed hole, and rotating the through hole or the bottomed hole. In the nozzle vane 1, the nozzle throat (nozzle opening) varies greatly depending on the slight rotation angle, and therefore it is not possible to define the angle θ between the protruding direction of the blade 12 and each flat portion 15 with high accuracy. Very important.

(Blade machining process (first blade machining process))
Further, when forming the blade portion 52D (first blade processing step), the shaft portion 51C side of the blade portion 52C is formed so as to form an end surface on the shaft portion 11 side of the blade portion 12 of the nozzle vane 1 finally obtained. The end face is cut and / or ground to form the wing 52D.
In the first blade processing step (blade processing step), the width of the blade portion 52C of the sintered body 50C in plan view is adjusted by the processing. Thereby, the dimensional accuracy of the width | variety (band-like width in planar view) of the wing | blade part 12 obtained can be made excellent. Further, since the machining allowance at that time can be reduced, it is possible to shorten the time required for machining as compared with the case of using precision casting while improving the dimensional accuracy. More specifically, for example, the accuracy of the width of the wing portion of the material in plan view is
When manufactured by precision casting, it is about ± 0.2mm, so even if chamfering is provided on the material,
It will be removed by the above process. On the other hand, in the present invention, the accuracy of the width of the wing portion of the material in plan view is ±
It can be about 0.05 mm. Therefore, chamfering can be left even after the above processing.

The machining in this process can be performed using the center hole 14 in the same manner as the machining in the shaft machining process described above. Further, the shaft machining step and the first blade machining step may be performed sequentially or simultaneously.
Thus, after the firing step [1D] or after the shaft machining step, the wing portion 52C of the sintered body 50C is subjected to processing including cutting and / or grinding, thereby improving the dimensional accuracy of the obtained wing portion 12. Can be made.
Further, as described above, since the machining allowance is small, the chamfer 58 of the sintered body 50C described above.
The chamfer 18 can be formed by leaving a part of C after processing.

<1E2> Second machining step (blade machining step (second blade machining step))
Next, a process including a cutting process and / or a grinding process is performed on the end surface of the intermediate workpiece 50D obtained in the above step <1E1> on the side opposite to the shaft part 11 of the blade part 52D, and FIG. ), The wing part 12 is formed. Thereby, the nozzle vane 1 which has the axial part 11 and the wing | blade part 12 is obtained.

In this step <1E2>, when forming the blade portion 12 (second blade processing step), an end face opposite to the shaft portion 11 of the blade portion 12 of the nozzle vane 1 finally obtained is formed. Cutting and / or grinding is performed on the end surface of the wing 52D opposite to the shaft 11 to obtain the wing 1
2 is formed.
In the second blade processing step (blade processing step), the blade portion 52D of the intermediate workpiece 50D is obtained by the processing.
Adjust the width in plan view. Thereby, the width | variety of the wing | blade part 12 obtained (band shape width in planar view)
The dimensional accuracy can be made excellent. Further, since the machining allowance at that time can be reduced, it is possible to shorten the time required for machining as compared with the case of using precision casting while improving the dimensional accuracy.

The machining in this step <1E2> may be performed using the center hole 14 as in the above step <1E1>, or may be performed using the shaft portion 11 obtained in the above step <1E1>. Good.
The machine tool used for such processing is not particularly limited as long as it performs cutting and / or grinding using the center hole 14 or the shaft portion 11 as described above.
For example, a lathe) can be used.

In this way, the blade 52 of the intermediate workpiece 50D after the firing step [1D] or after the shaft machining step.
By performing processing including cutting and / or grinding on D, the dimensional accuracy of the obtained blade 12 can be improved.
Further, since the machining allowance is small as described above, the chamfer 17 can be formed by leaving a part of the chamfer 57C of the intermediate workpiece 50D described above after the machining.

The nozzle vane 1 can be manufactured as described above.
According to the method for manufacturing the nozzle vane 1 as described above, the sintered body 50C is formed from the molded body 50.
Since it becomes a similar shape of A, it can be manufactured with superior dimensional accuracy compared to precision casting without causing problems such as warpage. Further, by forming the center hole 54A to be the center hole 14 in the molding step [A], the position accuracy of the center of the center hole 14 is extremely excellent. Therefore, by using such a center hole 14 to perform processing including cutting and / or grinding on the shaft portion 51C of the sintered body 50C, the processing allowance for the processing is extremely reduced, and as a result. The processing time can be shortened. Moreover, the dimensional accuracy of the obtained nozzle vane 1 can be made excellent.

In addition, the difference between the hardness near the surface and the internal hardness of the sintered body 50C can be made small, and the internal hardness of the sintered body 50C can be made extremely high. Therefore, the obtained nozzle vane 1 has an extremely high hardness even in a portion subjected to the above processing, and can exhibit excellent durability.
Furthermore, since a dedicated machine tool for forming the center hole 14 is not required, the equipment cost can be reduced. Therefore, the nozzle vane 1 as described above can be manufactured at low cost.

Second Embodiment
Next, a second embodiment of the present invention will be described.
FIG. 9 is a side view of the nozzle vane according to the second embodiment of the present invention (a view when the wing portion is viewed in plan), and FIG. 10 is a front view and a rear view of the nozzle vane shown in FIG. The figure seen from the opposite side to a lever plate, (b) is the figure seen from the lever plate side.
Hereinafter, the nozzle vane and the manufacturing method thereof according to the second embodiment will be described with a focus on differences from the first embodiment described above, and description of similar matters will be omitted.

(Nozzle vane)
A nozzle vane 1A according to the second embodiment of the present invention is a double-shaft type, and is the same as that of the first embodiment described above except that the shapes of the wing portion and the shaft portion are different.
More specifically, the nozzle vane 1A of the present embodiment has a pair of shaft portions 11A and 11B and a wing portion 12A as shown in FIG. In the present embodiment, the shaft portion 11
On the other end of A (the end on the left side in FIG. 9), a flange portion 16A that protrudes outside the shaft portion 11A.
Is formed. Similarly, a flange portion 16B that protrudes outside the shaft portion 11B is formed at the other end portion (right end portion in FIG. 9) of the shaft portion 11B.

As shown in FIG. 10, each of the shaft portions 11 </ b> A and 11 </ b> B has a circular shape with the axis 13 as the central axis. In the present embodiment, the shaft portion 11A includes the first portion 111,
It has a second part 112 and a third part 113. The first portion 111 has a shaft portion 11.
It is a portion that is provided on the wing portion 12A side of A and is rotatably supported by the nozzle mount 2. The second portion 112 is a portion that is provided on the opposite side of the wing portion 12 </ b> A of the shaft portion 11 </ b> A and is fixed to the lever plate 4. The second portion 112 is formed to have a smaller outer diameter than the first portion 111. The third portion 113 is provided between the first portion 111 and the second portion 112, and the outer diameter gradually decreases from the first portion 111 side to the second portion 112 side.

The shaft portion 11B is rotatably supported by the support plate 5. In the case of the present embodiment, the support plate 5 is formed with an engaging portion constituted by a through hole, a bottomed hole, or the like for rotatably supporting the shaft portion 11B.
A center hole 14A is formed in one end surface (the right end surface in FIG. 9) of the shaft portion 11A. Further, a center hole 14B is formed in one end surface (left end surface in FIG. 9) of the shaft portion 11B. These center holes 14 </ b> A and 14 </ b> B are formed so that their centers coincide with the axis 13. That is, the center holes 14A and 14B have their centers located on the same axis.

Such center holes 14A and 14B are formed by a powder metallurgy method, as will be described later. In the shaft machining step and the blade machining step in the manufacturing process of the nozzle vane 1A,
It is used by engaging with the center of a machine tool (processing device) such as a lathe.
In addition, a pair of flat portions 15A (two-surface cut portions) facing each other via the axis 13 is provided on the outer peripheral surface on one end side (right side in FIG. 9) of the shaft portion 11A (FIG. 10 ( a)).

In the present embodiment, each flat portion 15A is formed so as to be substantially perpendicular to the protruding direction (wing surface) of the wing portion 12A.
A wing portion 12A is provided between the shaft portion 11A and the shaft portion 11B, that is, in the middle of the shaft portion constituted by the shaft portion 11A and the shaft portion 11B. Such nozzle vane 1A
Since each of the pair of shaft portions 11A and 11B needs to be processed, the effect of applying the present invention is particularly remarkable from the viewpoint of shortening the processing time.

As shown in FIG. 9, the wing portion 12A has an axial line 1 of the shaft portions 11A and 11B in a plan view.
3 is in the form of a band extending in a direction perpendicular to 3. Further, the protruding length of the wing part 12A from the shaft part 11A is substantially equal on one end side (lower side in FIG. 9) and the other end side (upper side in FIG. 9).
Further, chamfers 17A and 18A are applied to the edge portions at both ends in the width direction (left and right direction in FIG. 9) in plan view of the wing portion 12A.
Further, as shown in FIGS. 10A and 10B, the wing portion 12 </ b> A extends substantially linearly in a direction perpendicular to the axis 13. Further, the thickness of the main portion of the wing portion 12A is one end side (FIG. 1).
It gradually decreases from the right side at 0 to the other end side (left side in FIG. 10).

The nozzle vane 1A configured as described above includes the shaft portions 11A and 11B and the wing portion 1.
2A is integrally formed by a powder metallurgy method, and the shaft portion 11A is subjected to processing including cutting and / or grinding in a portion other than the center hole 14A, and the shaft portion 11B is other than the center hole 14B. The part is subjected to processing including cutting and / or grinding.
According to such a nozzle vane 1A, as with the nozzle vane 1 of the first embodiment described above, it has excellent durability and can exhibit desired characteristics.

(Nozzle vane manufacturing method)
Next, the manufacturing method of the nozzle vane 1 of the present invention will be described taking the manufacturing method of the nozzle vane 1 configured as described above as an example.
11 and 12 are views (side views) for explaining the method for manufacturing the nozzle vane shown in FIG.

The manufacturing method of the nozzle vane 1A includes: [2A] a molding step for manufacturing a molded body, [2B] a degreasing step for performing a degreasing process, [2C] a preliminary processing step for performing preliminary processing, and [2D] a baking step for performing baking. And [2E] a machining process (including a shaft machining process and a blade machining process) for performing the main machining.
Hereafter, each process is demonstrated in detail in order of a process.

[2A] Molding process <2A1>
First, a metal powder and an organic binder are prepared and kneaded with a kneader to obtain a kneaded product (composition) (composition preparation step).
This step <2A1> can be performed in the same manner as the step <1A1> in the method for manufacturing the nozzle vane 1 of the first embodiment described above.

<2A2>
Next, the kneaded product obtained in the step 2A1 is molded to produce a molded body 60A as shown in FIG.
The molded body 60A has the same shape (similar shape) as the sintered body 60C obtained in step [2D] described later. More specifically, the molded body 60A includes shaft portions 61A and 69A and wing portions 62A formed so as to protrude from between the shaft portions 61A and 69A in a direction perpendicular to the axis 13 thereof.
And. Here, although there is a difference in machining allowance, the molded body 60A is composed of a nozzle vane 1A.
And almost the same shape. Therefore, a center hole 64A is formed on the end surface of the shaft portion 61A.
A pair of flat portions 65A is formed on the outer peripheral surface of the shaft portion 61A. In the present embodiment, a center hole 71A is formed on the end surface of the shaft portion 69A, and the shaft portion 61A is formed of the first portion 611.
A, a second portion 612A, and a third portion 613A.
Further, chamfers 67A and 68A are provided on the edge of the wing portion 62A.
This step <2A2> can be performed in the same manner as the step <1A2> in the method for manufacturing the nozzle vane 1 of the first embodiment described above.

[2B] Degreasing step Degreasing treatment (debinding treatment) is performed on the molded body 60A obtained in the above step [2A] to obtain a degreased body 60B as shown in FIG.
Here, the degreased body 60B has the same shape (similar shape) as the molded body 60A. More specifically, the degreased body 60B includes shaft portions 61B and 69B, and a wing portion 62B formed so as to protrude from between the shaft portions 61B and 69B in a direction perpendicular to the axis 13 thereof. A center hole 64B is formed on the end surface of the shaft portion 61B, and a pair of flat portions 65B is formed on the outer peripheral surface of the shaft portion 61B. In this embodiment, the center hole 7B is formed in the end surface of the shaft portion 69B.
1B is formed, and the shaft portion 61B has a first portion 611B, a second portion 612B, and a third portion 613B. Further, chamfers 67B and 68B are formed at the edge of the wing portion 62B.
This step <2B> is a step in the method for manufacturing the nozzle vane 1 of the first embodiment described above.
1B>.

[2C] Preliminary processing step Next, if necessary, preliminary processing including a cutting step and / or a grinding step is performed on the shaft portions 61B and 69B and / or the blade portion 62B of the degreased body 60B.
Since the degreased body 60B is relatively soft, it is easy to process. Therefore, by performing such a preliminary processing step after the degreasing step [2B] and before the firing step [2D], the time required for processing is made excellent in the dimensional accuracy of the finally obtained nozzle vane 1A. Can be further shortened.
The processing in this step can be performed in the same manner as the processing in the processing step [2E] described later.

[2D] Firing step The degreased body 60B obtained in the above step [2B] (or the pre-processed degreased body 60B obtained in the above step [2D]) is fired and sintered in a firing furnace. As shown in FIG. 11C, a sintered body 60C is manufactured.
Here, the sintered body 60C has the same shape (similar shape) as the degreased body 60B. More specifically, the sintered body 60C includes shaft portions 61C and 69C, and a blade portion 62C formed so as to protrude from between the shaft portions 61C and 69C in a direction perpendicular to the axis 13 thereof. A center hole 64C is formed on the end surface of the shaft portion 61C, and a pair of flat portions 65C is formed on the outer peripheral surface of the shaft portion 61C. In the present embodiment, the center hole 7C is formed in the end surface of the shaft portion 69C.
1C is formed, and the shaft portion 61C has a first portion 611C, a second portion 612C, and a third portion 613C. Further, chamfers 67C and 68C are formed at the edge of the wing portion 62C. Here, the center hole 64C constitutes the center hole 14A of the nozzle vane 1A. The center hole 71C constitutes the center hole 14B of the nozzle vane 1A.
This step <2D> is a step <1 in the method for manufacturing the nozzle vane 1 of the first embodiment described above.
1D>.

[2E] Processing Step Next, the sintered body 60C obtained in the above step [2D] is subjected to processing (main processing) including cutting and / or grinding to form the nozzle vane 1A.
In the present embodiment, the processing step [2E] is a first process in which processing including cutting and / or grinding is performed on the end surfaces of the shaft portion 61C of the <2E1> sintered body 60C and the shaft portion 61C of the blade portion 62C.
And the shaft portion 69C and the blade portion 62C of the <2E2> sintered body 60C (step <2E1>
There is a second processing step of performing processing including cutting and / or grinding on the end surface of the rear blade portion 62D) opposite to the shaft portion 61C.
That is, this step [2E] includes an axial machining step in which the shaft portions 61C and 69C of the sintered body 60C are subjected to processing including cutting and / or grinding, and a wing portion 62C (wing portion 62) of the sintered body 60C.
D) includes a blade processing step for performing processing including cutting and / or grinding.

Hereinafter, the first processing step <2E1> and the second processing step <2E2> will be sequentially described in detail.
<2E1> First Processing Step In the processing step [1E], first, the axis of the sintered body 60C (material) obtained using the steps [1A] to [1D] (that is, the powder metallurgy method) as described above. Shaft portion 5 of portion 61C and wing portion 62C
Processing including cutting and / or grinding is performed on the end surface on the 1C side to obtain an intermediate workpiece 60D as shown in FIG.

Here, the intermediate workpiece 60D includes shaft portions 11A and 69C, and a wing portion 62D formed so as to protrude from between the shaft portions 11A and 69C in a direction perpendicular to the axis 13 thereof. And
A center hole 14A is formed on the end surface of the shaft portion 11A, and a pair of flat portions 15A is formed on the outer peripheral surface of the shaft portion 11A. Further, chamfers 67C and 18A are formed at the edge of the wing portion 62D.

(Axis machining process (first axis machining process))
In this step <2E1>, the shaft portion 61C is formed when the shaft portion 11A is formed (first shaft machining step).
A shaft having a desired outer diameter and an axial position by performing cutting and / or grinding on a portion other than the pair of flat portions 65C in the outer peripheral surface of a portion (corresponding to the shaft portion 61A of the molded body 60A). Part 11A is formed.

In the present embodiment, such processing is performed on the outer peripheral surface of the first portion 611C of the shaft portion 61C. Such a portion is a portion that is rotatably supported by the nozzle mount 2. By forming the portion with high accuracy, the positional accuracy of the installation of the nozzle vane 1 </ b> A can be made highly accurate. On the other hand, portions other than the first portion 611C of the shaft portion 61C, that is, the second portion 612C and the like have the necessary dimensional accuracy regardless of the positional accuracy of the installation of the nozzle vane 1A.
The above processing can be omitted.
In particular, in the processing of this step <2E1>, the center hole 14A and / or the center hole 1
4B can be used, but it is preferable to use both the center hole 14A and the center hole 14B. Thereby, said process can be made more highly accurate.

(Blade machining process (first blade machining process))
Further, when forming the blade portion 62D (first blade processing step), the shaft portion 61C of the blade portion 62C is formed so as to form an end surface on the shaft portion 11A side of the blade portion 12A of the finally obtained nozzle vane 1A.
The end face on the side is subjected to cutting and / or grinding to form the wing 62D.
In the first blade processing step (blade processing step), the width of the blade portion 62C of the sintered body 60C in plan view is adjusted by the processing.

The machining in this step can be performed using the center hole 14A and / or the center hole 14B in the same manner as the machining in the first shaft machining process described above. Further, the first shaft machining step and the first blade machining step may be performed sequentially or simultaneously.
This step <2E1> can be performed in the same manner as the step <1E1> in the method for manufacturing the nozzle vane 1 of the first embodiment described above.

<2E2> Second processing step Next, the end surface on the shaft portion 69C side of the intermediate workpiece 60D and the shaft portion 69C side of the blade portion 62D is subjected to processing including cutting and / or grinding processing, and FIG. As shown, a nozzle vane 1A is obtained.

(Axis machining process (second axis machining process))
In this step <2E2>, the shaft portion 69C is formed when the shaft portion 11B is formed (second shaft machining step).
Cutting and / or grinding is performed on the outer peripheral surface of the (the portion corresponding to the shaft portion 69A of the molded body 60A) to form the shaft portion 11B having a desired outer diameter and an axial position.
(Wing machining process (second wing machining process))
Further, when forming the blade portion 12A (second blade processing step), the blade portion is formed so as to form an end surface on the shaft portion 69C side (shaft portion 11B side) of the blade portion 12A of the nozzle vane 1A finally obtained. Cutting and / or grinding are performed on the end surface of the 62D shaft portion 69C side to form the wing portion 12A.

In the second blade processing step (blade processing step), the width of the blade portion 62D in plan view is adjusted by the processing.
The machining in this step can be performed using the center hole 14A and / or the center hole 14B in the same manner as the machining in the first shaft machining step described above, and instead of the center hole 14A,
11 A of shaft parts obtained at said process <E1> can also be used.
The nozzle vane 1A can be manufactured as described above.

As mentioned above, although the manufacturing method of the nozzle vane of this invention, the nozzle vane, the variable nozzle mechanism, and the turbocharger were demonstrated based on suitable embodiment, this invention is not limited to this.
For example, in the manufacturing method of a nozzle vane, arbitrary processes can also be added as needed.

Further, the shape of the nozzle vane is limited to that of the above-described embodiment as long as it includes a shaft portion and a wing portion formed so as to protrude from the shaft portion in at least one direction perpendicular to the axis. For example, the wing portion may be formed so as to protrude from the shaft portion in one direction perpendicular to the axis.
In the above-described embodiment, the case where a pair of flat portions is provided has been described, but the number of flat portions is one.
There may be one or three or more.

1 is a longitudinal sectional view showing a turbocharger according to a first embodiment of the present invention. FIGS. 1A and 1B are views for explaining a variable nozzle mechanism provided in the turbocharger shown in FIG. 1, where FIG. 1A is a view from the lever plate side, and FIG. . It is a figure (front view seen from the lever plate side) for demonstrating an effect | action of the variable nozzle mechanism shown in FIG. FIG. 3 is a side view of a nozzle vane provided in the variable nozzle mechanism shown in FIG. FIG. 5 is a front view and a rear view of the nozzle vane shown in FIG. 4 ((a) is a view seen from the side opposite to the lever plate, (b) is a view seen from the lever plate side). It is process drawing for demonstrating the manufacturing method of the nozzle vane of this invention. It is a figure (side view) for demonstrating the manufacturing method of the nozzle vane shown in FIG. It is a figure (side view) for demonstrating the manufacturing method of the nozzle vane shown in FIG. It is a side view (figure when the blade part is seen in plane) of the nozzle vane concerning a 2nd embodiment of the present invention. FIG. 9 is a front view and a rear view of the nozzle vane shown in FIG. 9 ((a) is a view from the side opposite to the lever plate, and (b) is a view from the lever plate side). It is a figure (side view) for demonstrating the manufacturing method of the nozzle vane shown in FIG. It is a figure (side view) for demonstrating the manufacturing method of the nozzle vane shown in FIG.

Explanation of symbols

1, 1A ... Nozzle vane 2 ... Nozzle mount 3 ... Drive link 3a ...
Groove 3b …… Drive groove 4 …… Lever plate 4a …… Connecting pin 4b …… Through hole 5
…… Support plate 6 …… Nozzle support 10 …… Turbocharger 11, 11A
11B, 51A, 51B, 51C, 61A, 61B, 61C, 69A, 69B, 69C ...
... Shaft part 12, 12A, 52A, 52B, 52C, 52D, 62A, 62B, 62C, 6
2D: Wings 13: Axis 14, 14A, 14B, 54A, 54B, 54C, 64A
, 64B, 64C, 71A, 71B, 71C ... Center hole 15, 15A, 55A, 55
B, 55C, 65A, 65B, 65C: Flat part 16, 16A, 16B ... Flange part 17, 18, 17A, 18A, 57A, 57B, 57C, 58A, 58B, 58C, 6
7A, 67B, 67C, 68A, 68B, 68C ... Chamfer 20 ... VG turbine 2
1 …… Turbine wheel 22 …… Turbine casing 23 …… Variable nozzle mechanism 24
…… Drive mechanism 25 …… Scroll 26 …… Exhaust gas outlet 27 …… Actuator rod 28 …… Actuator 30 …… Compressor 31 …… Compressor wheel 32 …… Compressor casing 41 …… Bearing housing 42 …… Bearing 43 ……
Turbine rotor 44 …… Rotation axis 50A, 60A …… Molded body 50B, 60B …… Degreased body 50C, 60C …… Sintered body 50D, 60D …… Intermediate workpiece 111,611A,
611B, 611C ... 1st part 112, 612A, 612B, 612C ... 2nd part 113, 613A, 613B, 613C ... 3rd part

Claims (17)

A composition containing a metal powder and an organic binder is molded, and a shaft portion, a wing portion formed so as to protrude from the shaft portion in at least one direction perpendicular to the axis, and at least one of the shaft portions A molding step of obtaining a molded body having a center hole formed on the end surface;
A degreasing step of removing the organic binder from the molded body to obtain a degreased body;
Firing the degreased body to obtain a sintered body;
A shaft processing step of performing processing including cutting processing and / or grinding processing on a portion corresponding to the shaft portion of the sintered body using a portion corresponding to the center hole of the sintered body. Nozzle vane manufacturing method. The method of manufacturing a nozzle vane according to claim 1, wherein in the shaft machining step, the machining is performed on a portion other than an end surface of a portion corresponding to the shaft portion of the sintered body. 3. The blade processing step according to claim 1, further comprising a blade processing step of performing processing including cutting processing and / or grinding processing on a portion corresponding to the blade portion of the sintered body after the firing step or after the shaft processing step. Nozzle vane manufacturing method. The wing portion has a band shape orthogonal to the axis of the shaft portion in plan view, and in the wing processing step, the portion corresponding to the wing portion of the sintered body by the processing is shown in plan view. The manufacturing method of the nozzle vane of Claim 3 which adjusts the width | variety of. The method for manufacturing a nozzle vane according to claim 3 or 4, wherein, in the molding step, chamfering is performed on an edge portion of the wing portion. After the degreasing step and before the firing step, a preliminary processing step of performing preliminary processing including cutting and / or grinding processing on a portion corresponding to the wing portion and / or the shaft portion of the degreased body. A method for producing a nozzle vane according to any one of claims 1 to 5. In the molding step, a flat portion is formed on the outer peripheral surface of the shaft portion,
The method for manufacturing a nozzle vane according to any one of claims 1 to 6, wherein in the shaft machining step, the machining is performed on a portion other than a portion corresponding to the flat portion of the sintered body. The said flat part is a manufacturing method of the nozzle vane of Claim 7 provided in one pair through the axis line of the said axial part. The method for manufacturing a nozzle vane according to claim 7 or 8, wherein the flat portion is for restricting a rotation angle around an axis of the shaft portion by being applied to a contact surface. The method of manufacturing a nozzle vane according to claim 1, wherein the wing portion is provided so as to protrude from one end portion of the shaft portion. The method for manufacturing a nozzle vane according to claim 1, wherein the wing portion is provided so as to protrude from the middle of the shaft portion. The method for manufacturing a nozzle vane according to claim 1, wherein in the molding step, the molded body is obtained by a metal powder injection molding method. A nozzle vane manufactured by the method for manufacturing a nozzle vane according to claim 1. A nozzle vane comprising a shaft portion and a wing portion formed so as to protrude from the shaft portion in at least one direction perpendicular to the axis line,
The wing part and the shaft part are integrally formed by powder metallurgy,
A center hole is formed in at least one end surface of the shaft portion, and the shaft portion is subjected to processing including cutting and / or grinding processing in a portion other than the center hole. . Vickers hardness H of the surface of the processed part including cutting and / or grinding
A is 200 or more and A / B is 0.6-1 when V is A and Vickers hardness HV of the surface of the part which is not processed is B. 13 or 14
Nozzle vane as described in. A variable nozzle mechanism comprising a plurality of nozzle vanes according to claim 13.   A turbocharger comprising the variable nozzle mechanism according to claim 16.

Images