JP2007023841A - Method of manufacturing variable blade in vgs type turbocharger and variable blade manufactured by this method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a novel manufacturing technique for trying blanking for improving a yield of a material by taking into consideration a material flow in a molding process when particularly mass-producing a variable blade of twin-shaft type in a VGS type turbocharger. <P>SOLUTION: This invention comprises a blank preparing process P1 of blanking a blank W being a prototype of the variable blade 1 and the molding process of sandwiching and forming the blank W in a desired shape by opposed molds; and is characterized in that in blanking, the thick front edge 11a side forms a thickening recessed part 17a in the substantial center of a front edge part, and in molding processing thereafter, the thickness of both end parts thickens and is finally filled up, and the thin wall rear edge 11b has a flow passage recess 17b on both end sides, and is formed in a tapered shape sufficiently narrower than a blade width (h), and in molding thereafter, the thickness extends over the whole, and the rear edge tip side blanks a blade part 11 in a plane shape of forming the desired blade width (h). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a turbocharger used for an automobile engine or the like, and in particular, in manufacturing a double-shaft type variable blade incorporated in the turbocharger, the efficiency specialized in the shape of such a variable blade, etc. This relates to a novel manufacturing method that makes a practical mass production method realistic.

  A turbocharger is known as a turbocharger that is used as a means to increase the output and performance of an automobile engine. This turbocharger drives the turbine by the exhaust energy of the engine, and rotates the compressor by the output of the turbine. It is a device that brings the engine to a supercharged state that is higher than natural intake. By the way, in this turbocharger, when the engine rotates at a low speed, the exhaust turbine hardly works due to a decrease in the exhaust flow rate. Then, the time required to blow up all at once, it was inevitable that a so-called turbo lag would occur. In addition, a diesel engine having a low engine speed originally has a drawback that it is difficult to obtain a turbo effect.

  For this reason, VGS type turbochargers (VGS units) have been developed that operate efficiently even in the low rotation range. In this system, a small exhaust flow rate is narrowed down with variable blades (blades), the exhaust speed is increased, and the work of the exhaust turbine is increased so that a high output can be exhibited even at a low speed. For this reason, in the VGS unit, a variable mechanism of a variable wing is required separately, and peripheral components have to be made more complicated in shape and the like than the conventional one.

  For this reason, the present applicant has also earnestly researched and developed the variable wing and its variable mechanism, and has made many patent applications (see, for example, Patent Documents 1 to 8). In this patent document, a manufacturing method is disclosed in which a variable blade is formed into a desired shape by press-molding a blank material punched from a metal plate material having a certain thickness, for example, by die forging. In this patent document, the variable wing mainly has a so-called cantilever structure in which a shaft portion is mainly formed only at one end portion of the wing portion. However, the variable wing is for adjusting the flow rate of the exhaust gas by appropriately rotating the wing, and since the opening and closing operation is repeated under a high temperature / exhaust gas atmosphere, the strength and the operational stability are improved. In addition, in view of reducing the weight and size of the VGS unit itself, it is desirable to have both ends, that is, a type in which shaft portions are formed on both sides of the wing portion. For this reason, at present, the variable wing is also being used in a double-shaft type, and along with the change in the shape of the variable wing, the manufacturing method has been reviewed. In particular, the present invention focuses on blank removal in consideration of the material flow during modeling processing in order to efficiently manufacture variable wings.

In addition, about 10 to 15 variable wings are often used in a single turbocharger. For example, when about 30,000 vehicles are actually mass-produced per month, It is necessary to manufacture 300,000 to 450,000 pieces at a time, and a manufacturing method that can actually be adopted by a mass production system is a major premise.
In recent years, especially in diesel vehicles, exhaust gas released into the atmosphere is strongly regulated from the viewpoint of environmental protection, etc., and in diesel engines with low engine speed, NO _x and particulate matter ( In order to reduce (PM) and the like, mass production of VGS units capable of improving engine efficiency from a low rotation range has been desired.
JP 2003-49655 A JP 2003-49663 A JP 2003-49656 A JP 2003-49657 A JP 2003-49658 A JP 2003-49659 A JP 2003-48033 A JP 2003-49660 A

  The present invention has been made in view of such a background, and in mass production of variable-shafts of both shaft types, a novel blank removal that can improve the material yield while considering the material flow in the molding process. This is an attempt to develop a new manufacturing method that makes it possible to realize a variable blade with a stable and high quality level, mass productivity and economy.

That is, the manufacturing method of the variable blade in the VGS type turbocharger according to claim 1 is:
It includes a shaft portion serving as a rotation center and a wing portion that substantially adjusts the flow rate of exhaust gas,
A relatively small amount of exhaust gas discharged from the engine is appropriately throttled, the speed of the exhaust gas is amplified, the exhaust turbine is rotated by the energy of the exhaust gas, and air that exceeds natural intake is sent to the engine by a compressor directly connected to this exhaust turbine. When manufacturing variable wings incorporated in a VGS type turbocharger that allows the engine to exhibit high output even at low speeds,
A blank material punched out from a metal material having a substantially constant plate thickness so as to have a volume capable of realizing the target variable blade is used as a raw material that is the original shape of the variable blade. When,
The material is sandwiched between a pair of opposed molds, and includes at least a modeling step of forming a wing part, a shaft part, or the like into a desired shape,
In addition, the wing portion has a thick wing shape on the leading edge side and a thin wing-shaped cross section on the trailing edge side,
Furthermore, in performing blank removal in the preparation process of the above-mentioned shaped material,
For the leading edge side of the wall thickness, a meat gathering recess is formed almost in the middle of the front edge, and at the time of subsequent modeling processing, the meat on both ends approaches and finally fills,
On the thin trailing edge side, there is a recess for sinking on both ends, and it is formed in a taper shape that is sufficiently narrower than the wingspan. The wing portion is blanked into a planar shape that forms a desired blade width.

  Further, in the VGS type turbocharger according to claim 2, in addition to the requirement of claim 1, the manufacturing method of the variable blade includes the step of preparing the forming material and the forming step of converting the forming material in the middle of processing into a metal plate material Progressive processing is performed by progressively feeding them while being connected to a part of the metal. Also, for the shape material that is connected to a part of the metal plate, the thick leading edge side and the thin trailing edge side are used. Are arranged in a point-symmetrical state, different edges are directed toward the feeding direction, and blanking is performed in this state.

  Furthermore, the variable wing manufacturing method for a VGS type turbocharger according to claim 3 is characterized in that, in addition to the requirement of claim 1 or 2, the variable wing includes a long shaft portion and a short shaft portion on both sides of the wing portion. Further, it is characterized in that a collar portion having a diameter larger than the thickness of the blank material is formed between the blade portion and the shaft portion.

  According to a fourth aspect of the present invention, in the VGS type turbocharger, in addition to the requirements of the second or third aspect, the method of manufacturing the variable blade is connected to a metal plate material when blanking is performed in the step of preparing the shaped material. It is characterized in that a blank is taken in a state in which the pitch L1 of the raw material is as close as possible to the chord length L of the variable wing in the finished product state.

  The variable wing in the VGS type turbocharger according to claim 5 comprises a shaft portion serving as a rotation center and a wing portion that substantially adjusts the flow rate of the exhaust gas, and a relatively small amount of exhaust gas discharged from the engine. The exhaust gas speed is amplified, the exhaust gas speed is amplified, the exhaust turbine is rotated by the energy of the exhaust gas, and the air directly above the natural intake air is sent to the engine by the compressor directly connected to the exhaust turbine. A variable wing incorporated in a VGS type turbocharger capable of exhibiting a high output, which is manufactured by the manufacturing method according to claim 1, 2, 3 or 4. .

The above-described problems can be solved by using the configuration of the invention described in each of the claims.
That is, according to the first aspect of the present invention, when blanking is performed, blanking is performed in advance with a wing shape that sufficiently considers the material flow in the subsequent modeling process. The target shape can be realized faithfully.

  According to the invention described in claim 2, when the blank is formed by connecting the shaped member to a part of the metal plate, the thick leading edge and the thin trailing edge are staggered with respect to the feeding direction. Therefore, escape (acting) acting on the shaped material by the compression of each opposed type can be suppressed as much as possible, and the machining position with respect to the opposed type can be stabilized. For this reason, a desired modeling process can be more reliably performed with respect to a raw material.

  According to the invention described in claim 3, the variable wing of the double shaft type having the shaft portions on both sides of the wing portion is to be manufactured, and the thickness of the metal plate material is between the wing portion and the shaft portion. However, it is necessary to bulge the blank material that is the starting material for the heel part, so this is a very difficult processing method. Shall be. In other words, the heel part must be formed so as to swell the starting material, and therefore, it is necessary to regulate the material flow in the longitudinal direction of the shaft part, which is extremely difficult to manufacture. And In general die forging, a blank material is sandwiched between a pair of opposed dies, and the blank material is extended freely around the entire periphery by this compression to form a desired shape. In other words, during forging, the flow direction of the material is not particularly restricted, but in the present invention, due to the unique shape of the variable blade, the flow direction of the material must be restricted, which is much higher than usual. This is a highly difficult manufacturing method.

  According to the invention described in claim 4, since the pitch L1 of the shaped material connected to the metal plate material is set as close as possible to the chord length L of the variable blade (final product shape), the metal plate material is effectively used. Available. In addition, when the variable wing has a flange having a diameter larger than the plate thickness on both sides of the wing, it is necessary to restrict the material to flow in the axial direction at the time of modeling. That is, in this case, the material flow during modeling is generally allowed in the direction of the pitch L1, and in this sense, it is advantageous in terms of workability to increase the pitch L1 of the raw material. However, in the present invention, the pitch L1 is intentionally set to be approximately the same as the chord length L to improve the yield of the metal plate material.

  Further, according to the invention described in claim 5, for example, it is possible to efficiently mass-produce, for example, a double-shaft type variable blade with a constantly high quality level.

  The best mode of the present invention is as described in the following examples. In the description, first, the exhaust guide assembly A in the VGS type turbocharger (VGS unit) to which the variable vane 1 according to the present invention is applied will be described, and the variable vane 1 will be described together. A method for manufacturing the variable blade 1 will be described.

  The exhaust guide assembly A adjusts the exhaust gas flow rate by appropriately narrowing the exhaust gas G particularly when the engine is running at a low speed. As shown in FIG. 1, as an example, the exhaust guide assembly A is provided on the outer periphery of the exhaust turbine T and substantially exhausts. A plurality of variable blades 1 for setting the flow rate, a turbine frame 2 for rotatably holding the variable blades 1, and a variable mechanism 3 for rotating the variable blades 1 at a constant angle so as to appropriately set the flow rate of the exhaust gas G. It is made up of. Each component will be described below.

  First, the variable blade 1 will be described. As an example, as shown in FIG. 1, a plurality of these are arranged in an arc shape along the outer periphery of the exhaust turbine T (approximately 10 to 15 with respect to one exhaust guide assembly A). The exhaust gas flow is adjusted by rotating approximately the same degree. The variable wing 1 includes a wing portion 11 and a shaft portion 12, which will be described below.

  First, the blade portion 11 is formed to have a constant width mainly in accordance with the width dimension of the exhaust turbine T. The cross section in the width direction is formed into an airfoil shape so that the exhaust gas G can be effectively exhausted. It is configured to go to the turbine T. Here, as shown in FIG. 1B, the width dimension of the wing part 11 is defined as a wing width h for convenience. Further, as shown in FIG. 2, the end edge that is thick in the airfoil cross section of the wing part 11 is the leading edge 11 a, the thin edge is the trailing edge 11 b, and the length from the leading edge 11 a to the trailing edge 11 b is as follows. The chord length is L. Furthermore, the wing portion 11 is formed with a flange portion 13 having a diameter slightly larger than that of the shaft portion 12 at a boundary portion (connection portion) with the shaft portion 12. The bottom surface (seat surface) of the flange portion 13 is formed on substantially the same plane as the end surface of the blade portion 11, and this plane becomes a seat surface when the variable blade 1 is attached to the turbine frame 2. It is responsible for regulating the position in the width direction (blade width h direction).

  On the other hand, the shaft portion 12 is formed integrally and continuously with the wing portion 11 and serves as a rotation shaft when the wing portion 11 is moved. In the present embodiment, the shaft portion 12 is formed on both sides of the wing portion 11 and is a so-called double-supported variable wing 1. When these shaft portions 12 are shown separately, the length depends on the axial length. Therefore, the major axis portion 12a and the minor axis portion 12b are distinguished for convenience. Incidentally, such a double-supported variable wing 1 has an operational stability (rotational stability) of the variable wing 1 as compared with a so-called cantilever type in which a shaft portion 12 is formed only on one of the wing portions 11. ) And strength can be improved.

  The long shaft portion 12a and the short shaft portion 12b are partially formed with a sliding step 14 having a diameter somewhat larger than the shaft diameter. This is a surface that comes into contact with a bearing portion on the turbine frame 2 side (a receiving hole 25 of the turbine frame 2 to be described later) when the variable blade 1 is rotated, thereby sliding when the variable blade 1 is rotated. The dynamic resistance (friction resistance) is suppressed, and stable operation (turning) of the variable blade 1 is achieved. Since the variable blade 1 is repeatedly used in a severe environment of high temperature and exhaust gas atmosphere, the suppression of the sliding resistance by the sliding step 14 further stabilizes the opening / closing operation in such a severe environment. It is.

  Further, a reference surface 15 serving as a reference for the mounting state of the variable wing 1 is formed on the distal end side of the long shaft portion 12a. The reference surface 15 is a part fixed to the variable mechanism 3 to be described later by caulking or the like, and as an example, as shown in FIGS. . Further, as shown in FIGS. 8 and 9, as an example, a leading edge 16 in which the opposite two surfaces are inclined in a tapered shape is formed at the tip portion of the reference surface 15, and this is a long axis. It is a site | part used as the guide guide at the time of pressing-in the part 12a to the passive element 32B mentioned later.

  As an example, the variable blade 1 has a thickness of the leading edge 11a of the blade portion 11 of about 2.711 mm, a blade width h of about 7.4 ± 0.03 mm, a chord length L of about 17.44 mm, and a flange portion 13. The seating surface has a diameter of about 6 mm. The diameter of the shaft portion 12 is about 4.5 mm, and the facing width of the reference surface 15 is about 2.45 mm.

Next, the turbine frame 2 will be described. This is configured as a frame member that rotatably holds a plurality of variable blades 1. As an example, as shown in FIG. 1, the variable blades 1 are sandwiched between a frame segment 21 and a holding member 22. Configured as follows. The frame segment 21 includes a flange portion 23 that receives the long shaft portion 12a of the variable wing 1 and a boss portion 24 that externally fits the variable mechanism 3 described later. With this structure, the same number of receiving holes 25 as the variable blades 1 are formed at equal intervals in the peripheral portion of the flange portion 23.
Further, as shown in FIG. 1, the holding member 22 is formed in a disk shape having an open central portion. In this embodiment, the variable wing 1 is a double-shaft type. The receiving holes 25 for receiving the one short shaft portion 12b are equally arranged.
The dimension between the two members is substantially constant (generally the blade of the variable blade 1 so that the variable blade 1 (wing portion 11) sandwiched between the frame segment 21 and the holding member 22 can be rotated smoothly at all times. As an example, the dimensions between the two members are maintained by caulking pins 26 provided at four places on the outer peripheral portion of the receiving hole 25. Here, a hole opened in the frame segment 21 and the holding member 22 to receive the caulking pin 26 is referred to as a pin hole 27.

  In this embodiment, the flange portion 23 of the frame segment 21 is composed of two flange portions, that is, a flange portion 23A having substantially the same diameter as the holding member 22 and a flange portion 23B having a diameter somewhat larger than the holding member 22. These are formed with the same member, but when it is difficult to form with the same member, two flange parts with different diameters are formed separately, and later by caulking or brazing, etc. It is also possible to join.

  Next, the variable mechanism 3 will be described. This is provided on the outer peripheral side of the boss portion 24 of the turbine frame 2 and rotates the variable blade 1 in order to adjust the exhaust flow rate. As an example, as shown in FIG. A rotating member 31 that causes the variable blade 1 to rotate and a transmission member 32 that transmits the rotation to the variable blade 1 are provided. As shown in the figure, the rotating member 31 is formed in a substantially disc shape with an opening at the center, and has the same number of transmission members 32 as the variable blades 1 at the periphery thereof. The transmission member 32 includes a drive element 32A that is rotatably attached to the rotating member 31, and a passive element 32B that is fixedly attached to the reference surface 15 of the variable wing 1 by caulking or the like. The rotation is transmitted in a state where the drive element 32A and the passive element 32B are connected. Specifically, a square piece drive element 32A is rotatably pinned to the rotating member 31, and the reference surface 15 of the variable blade 1 is press-fitted into the passive element 32B and caulked. Here, the passive element 32B is formed in advance with a substantially U-shaped portion that can receive the drive element 32A, and by engaging the square-shaped drive element 32A in this part, The rotating member 31 is attached to the boss portion 24.

In the initial state where a plurality of variable blades 1 are attached, in order to align them in a circumferential shape, each variable blade 1 and the passive element 32B must be attached at a substantially constant angle. Primarily, the reference surface 15 of the variable wing 1 performs this function. Further, if the rotating member 31 is simply fitted into the boss portion 24, there is a concern that when the rotating member 31 is slightly separated from the turbine frame 2, the engagement of the transmission member 32 is released. For this reason, in order to prevent this, the ring 33 etc. are provided so that the rotation member 31 may be pinched | interposed from the opposite side of the turbine frame 2, and the pressing tendency to the turbine frame 2 side is provided with respect to the rotation member 31. .
With such a configuration, when the engine rotates at a low speed, the rotation member 31 of the variable mechanism 3 is appropriately rotated and transmitted to the shaft portion 12 via the transmission member 32. The variable vane 1 is rotated as shown in FIG. 1A, and the exhaust gas G is appropriately throttled to adjust the exhaust gas flow rate.

An example of the exhaust guide assembly A to which the variable blade 1 according to the present invention is applied is configured as described above, and a method for manufacturing the variable blade 1 will be described below.
In this embodiment, a metal plate material (hereinafter referred to as 5.2 mm) having a plate thickness (5.2 mm) that is thinner than the diameter dimension (6 mm) of the flange 13 and larger than the diameter dimension (4.5 mm) of the shaft portion 12 (hereinafter, referred to as the following). A metal material (hereinafter referred to as a raw material W) that is the original shape of the variable blade 1 is blanked from the strip material S). The reason is as follows. That is, if the collar portion 13 is only formed, a material having the same diameter and the same thickness is optimal. However, since the ridge portion 13 is swelled by the material flow at the time of blade forging, it needs to be slightly thinner than the collar diameter. At the same time, if the shaft portion 12 is not thicker than the diameter of the shaft portion 12, the shaft portion 12 cannot be formed, and the compression resistance of the unequal thickness blade portion 11 is extremely large. This is because it is desirable to use the thinner side of the plate thickness corresponding to the shaft diameter dimension.

  Further, when blanking is performed, the individual blanks W are not punched out one by one from the strip material S, but are blanked while the blanks W to be processed are connected to a part of the strip material S. To do. That is, in this embodiment, the blank material (raw material W) that is still connected to a part of the strip material S is sequentially sent to the subsequent processing steps until the near net shape state (a state very close to the final product shape). It takes the form of so-called progressive processing (progressive processing).

Specifically, the raw material W is processed into the variable blade 1 of the final product by the following steps (1) to (7). Among these, the steps (1) to (5) are performed. This is done by progressive machining.
(1) “Shape blank process” as preparation process P1
(2) "First modeling process" as the pre-modeling process P2
(3) “Trim process” as intermediate trim process P3
(4) “Restoring process” as the final modeling process P4
(5) “Trim / separate process” as final trim process P5
(6) Cutting process P6
(7) Barrel polishing process

That is, in the progressive processing of this embodiment, as shown in FIG. 3 as an example, the opposing dies (press dies) from (1) to (5) above are sequentially arranged to form a processing line, The raw material W, which is still connected to the strip material S, is sequentially fed to such a processing line and molded to a near net shape state. In addition, the code | symbol D1-D5 in a figure shows the opposing type | mold corresponding to each process of progressive processing. Further, in the figure, a symbol UC is an uncoiler that unwinds the coil material (strip material S) in a wound state, and a symbol LV in the figure is a leveler that removes curl and distortion of the coiled material.
Incidentally, the above-described progressive processing is generally limited in terms of processing, for example, it is difficult to process the outer periphery of a semi-finished product (in the present embodiment, the shaped material W), or the semi-finished product cannot be reversed in the middle of the processing line. However, a very advanced technique is required as a press die, but since a relatively small part can be fed at a high speed, it is a processing method with extremely high productivity.

In addition, due to such a processing form, in progressive processing, it is necessary to correctly determine the position of the semi-finished product when performing each process, and therefore, a positioning reference hole (pilot hole PH) is used at the initial stage of processing. For example, it is performed prior to blanking or in combination with blanking (see FIG. 4).
Further, in the progressive machining, it is possible to incorporate a so-called idle stage that performs only the feeding without performing any machining on the semi-finished product due to the relationship with the preceding and following machining steps. For example, in this embodiment, as shown in FIG. 3, actual machining is performed in about 1/3 range of one machining area, and the remaining 2/3 range is set as an idle stage. Incorporation of such an idle stage in the processing line can prevent insufficient strength of the mold parts that may be caused by the approach of the mold, and can reduce the load applied to the mold during processing. In addition, it is possible to make fine adjustments to the inclination and machining timing of the raw material W during machining, and to prepare for unexpected design changes after line construction. Hereinafter, each step will be further described.

(1) Preliminary material preparation process P1 (shape blank process)
This step is a step of preparing a raw material W (original shape of the variable wing 1) integrally having the wing portion 11 and the shaft portion 12, and here, as described above, since progressive processing is performed, as an example, Unnecessary portions (this is referred to as scrap SC) are punched out from the strip material S having a thickness of 5.2 mm, and the raw material W is obtained with a part connected to the strip material S (see FIG. 4). Of course, in blanking, blanking is performed in consideration that the base material W has a volume (volume) that can realize the target variable blade 1.

Further, the blanking of the raw material W is preferably performed by a fine blanking process (hereinafter abbreviated as FB process) known as a precision punching method using a pair of opposed molds D1. This FB processing is a technique of punching in a so-called zero clearance state in which a high compressive force is applied to the shearing contour portion of the workpiece (strip material S) and the clearance of the tool is extremely small. This is a technique that is obtained in a very smooth and good state over the entire thickness. Normally, the term “fine blanking” indicates “precision punching”, but in the present specification, in the case of “fine blanking processing machine (FB processing machine)”, other than “precision punching”. In addition, various processes using a fine blanking device (FB device), such as coining, die forging, or trimming, are also included.
Further, as the material of the strip material S (shape material W), heat resistant stainless steel or heat resistant steel such as SUS or SUH standard, for example, stainless steel such as SUS310S, SUS304, or SUS316L is applied depending on the usage environment of the variable blade 1. In general, such a high Ni-containing stainless steel material is a material that is difficult to be plastically processed. Therefore, the processing in this embodiment is also inevitably highly difficult.

  Hereinafter, the blanking aspect in a present Example is demonstrated more concretely. In the present embodiment, as shown in FIG. 4 as an example, a spine-shaped crosspiece B (frame portion) connecting the raw material W is formed in the central portion of the strip material S, and a shape is formed with respect to the crosspiece B. The material W is connected oppositely and blanking is performed. In addition, since progressive processing is employed in this embodiment, the pilot hole PH is previously opened at a position corresponding to the crosspiece portion B.

  As described above, in this embodiment, the blank is removed while the raw material W is connected to the crosspiece B. However, it is possible to punch out the raw material W from the strip material S one by one. If a blank material such as a commercial product that has been punched into an appropriate shape in advance can be applied, this can be prepared and used as the preparation step P1 of the shaped material W. Incidentally, when blanks are formed so that the raw material W is separated from the strip material S one by one, or when blank materials that have been individually separated in advance are used as the raw material W, such blank material (raw material) The so-called transfer processing, in which W) is sent to subsequent processes by the feeder device one by one and sequentially processed, is preferable. In addition, since transfer processing has fewer restrictions on the mold than progressive processing, the degree of freedom on the production line is increased, but in terms of mass productivity, it is lower than progressive processing.

  Here, in the present invention, in the shape of blank removal, the following process, mainly the pre-modeling process P2 is taken into consideration, and this is explained, so this will be explained. The “modeling” described in this specification will be described. In the present specification, the process of shaping the base material W into an appropriate shape as a whole is referred to as forging (die forging), and the process of mainly giving an appropriate shape or pattern to the surface of the base material W is coined. These processes, that is, the overall and surface processes for the shaped material W are collectively referred to as “modeling”. In the present embodiment, die forging is taken as an example of such modeling processing.

  In general punching (blank removal), for example, as shown in FIG. 5 (b), the wing part 11 and the shaft part 12 are generally formed in a plane projection and are often punched as they are. As shown in FIGS. 4 and 5 (a) as an example, the shape of the wing part 11 is formed with a thickened concave part 17a at the substantially central part in a plan view, and the subsequent shaping process. At this time, it is considered that the meat approaches from both end portions of the front edge, and the meat gathering concave portion 17a is finally filled. Further, the thin trailing edge 11b is formed in such a manner that, when viewed from the top, the recess 17b for flesh flow is formed at both ends of the trailing edge, and the leading edge side of the trailing edge is tapered so as to be narrower than the blade width h. In the subsequent modeling process, it is considered that the meat extends as a whole and the leading edge side of the trailing edge forms a desired blade width h. Thus, in this invention, in the subsequent modeling process, the blank shape in which material flows easily is analyzed and utilized for blank removal.

Here, in the present invention, a description will be given of the actions and effects in which the material flow during the modeling process is considered in advance in the preceding blank removal.
In general, in die forging, a metal material (raw material W) is compressed with a facing mold to fill a cavity (material) in the cavity formed in the facing mold and forge into a desired shape. The material flow (direction) is not particularly restricted. However, in the present embodiment, the large-diameter flanges 13 are formed on both sides of the wing part 11, and the flanges 13 are larger in diameter than the plate thickness of the strip material S. Therefore, the material should be regulated so as not to flow as much as possible, and the portion forming the flange portion 13 should be forged so as to bulge (raise) the meat. In other words, in this embodiment, if the material flow in the axial direction is allowed as in general forging, it is very difficult to form the flange 13 in a bulging manner. For this reason, in this invention, the blank removal which considered the material flow fully is performed rather than normal die forging. Of course, the fact that the applicable material itself is a heat-resistant material that is extremely difficult to perform plastic working is also a factor that takes into account the material flow during forging.

Further, in this embodiment, due to the progressive processing in which the raw material W is sequentially fed while being connected to the strip material S (cross part B), the raw material attached to the cross part B oppositely. For W, as shown in FIGS. 4 and 5 (a) as an example, the thick front edge 11a side and the thin rear edge 11b side are arranged in a point-symmetrical state and are different from each other in the feed direction. Blanks are taken so that the edges are directed.
This is in order to cancel out the escape acting on the base material W by opposing compression during the subsequent modeling process. That is, the wing portion 11 has a thick front edge 11a and a thin rear edge 11b, so that the entire surface is inclined (airfoil shape). If it is set so that the same edge is directed to the feed direction, the shaped member W can easily escape along the airfoil surface when it is sandwiched between the opposed types (escape in the direction of the thick leading edge 11a). Easier). For this reason, it may be considered that the processing position of the shaped material W with respect to the opposed mold is not stable in some cases, and it is difficult to perform a desired modeling process. Are arranged in a staggered state to prevent such a rough shape W from being blown out and to ensure that a desired modeling process can be performed.

  In this embodiment, the pitch L1 (see FIGS. 4 and 5A) of the shaped member W attached to the crosspiece member B is made as close as possible to the chord length L in the final product shape when blanking. . Specifically, although depending on the thickness of the strip material S (the diameter of the shaft portion 12), when the chord length L is 17.44 mm, the pitch L1 is set to about 20 mm. In terms of this ratio, the pitch L1 is approximately 1.15 times the chord length L, but is preferably approximately 1.2 times in consideration of commercially significant production. This is a numerical value that is possible due to progressive processing using an FB processing machine and an FB processing die. Usually, in progressive processing, the ratio is about 1.5 times, so improvement in material yield and production are possible. It is extremely effective in that improvement in performance can be realized at the same time. The pitch L1 is thus set larger than the chord length L (L1> L). If the pitch L1 is set equal to the chord length L (L1 = L), for example, This is because in the final modeling step P4, the adjacent shaped members W come into contact after processing. Further, in this embodiment, since the flange portions 13 are formed on both sides of the wing portion 11, the material flow during modeling is mainly set in the pitch L1 direction. In this respect, the pitch L1 is set as large as possible. It is easier to perform modeling processing. However, if the pitch L1 is increased, the material utilization rate (yield) of the strip material S is reduced. Therefore, in this embodiment, the pitch L1 is made as close as possible to the chord length L to improve the yield. . Note that the pitch L1 of the base material W corresponds to a single transfer amount (movement amount) of feeding the strip material S in the progressive processing.

(2) Pre-modeling process P2 (first modeling process)
The modeling process is a process of forming the raw material W into a desired shape by sandwiching the raw material W with a pair of opposed molds by an FB device, for example. In particular, in this embodiment, the base material W is formed from a punched state (substantially square cross section) to a near-net shape state by two die forgings, and the first step of the two die forgings. Is the pre-modeling step P2 (first modeling step), and the second die forging is the final modeling step P4 (restriction). Here, the “modeling” described in the present specification means, as described above, a coining process that is superficially applied to the shaped material W in a near net shape state or a forging that is applied to the whole. It is a general term for processing.

In the pre-modeling step P2, the blade shape (airfoil shape) from the leading edge 11a to the trailing edge 11b is forged with an aim of a thickness of only 0.05 mm on one side as an example compared to the final product shape, This is because the final product shape cannot be formed in the final modeling step P4 unless a certain blade shape is formed in the pre-modeling step P2.
Further, in this pre-modeling step P2, the shaft diameter (as an example, the diameter of 4.5 mm) and the heel diameter (as an example, the diameter of 6 mm) are forged from this stage aiming at the final product shape, In particular, since the collar portion 13 has a size larger than the thickness of the strip material S to be blanked, if it is not surely bulged in the pre-modeling step P2, then the shape material is firmly and counter-type. This is because even if W is sandwiched, it is difficult to project it in a heaped shape simply by extending it around.

  Incidentally, in this type of die forging, usually, a material having a volume greater than the cavity volume (raw material W) is forged by strongly compressing with a counter die, and at this time, while filling the material into the cavity, Excessive material is deliberately discharged to the dividing surface of the mold, so that the base material W is precisely formed into a desired shape (cavity shape). However, since the inside of the cavity is a closed space, so to speak, depending on the shape and dimensions of the cavity, the material may flow out to the dividing surface before it sufficiently enters the cavity. In such a case, the material easily flows in the vicinity of the dividing surface, but the material does not easily flow in the cavity, and the bag-like portion 41 is formed in the cavity in which the material does not easily enter with respect to the dividing surface where the material easily flows ( (See FIG. 6).

Further, in order to smoothly feed the strip material S to each step of progressive processing, oil (lubricant O) for reducing frictional resistance may be applied to the surface of the strip material S, the opposing inner surface, or the like. In many cases, for example, as shown in FIG. 6C, the lubricant O sometimes accumulates in the bag-like portion 41 such as the shaft portion 12 or the flange portion 13, which further inhibits the flow of the material in the cavity. It becomes a factor.
For this reason, in this embodiment, for example, as shown in FIG. 6A, a straight oil drain hole 42 having a diameter of about 2 mm is formed as an example in the bag-shaped portion 41 of the opposed type D2, and thereby, in the cavity Promotes material flow. That is, even if the lubricant O accumulates in the bag-shaped portion 41 of the opposed type D2 that forms the shaft portion 12, the flange portion 13 and the like, the lubricant O that has entered here is removed by the compression operation of the opposed type D2 to the oil drain hole 42. So that the material can smoothly enter the cavity.
If there is a concern about the strength reduction of the opposing mold D2 due to the oil drain hole 42, for example, as shown in FIG. 6B, a spherical hole 43 is provided in the middle of the oil drain hole 42, and the stress applied to the opposing mold D2 Can be dispersed. It is also possible to divide the opposed type D2 on both sides of the oil drain hole 42 and form it as a separate member.

  In this embodiment, as described above, the forming material W is formed in a near net shape state through the two molding steps, but the present invention is not necessarily limited to this, and the shape of the final product and the strip material are not necessarily limited thereto. Depending on the type of metal material applied as S or the mold structure of the press die, it is possible to go through a plurality of modeling steps three or more times. In that case, everything except the last modeling process (final modeling process P4) becomes the prior modeling process P2.

(3) Intermediate trim process P3 (trim process)
This step is a step of cutting off unnecessary portions a that are unnecessary in performing the final modeling step P4, such as flash and burrs generated around the contour material W in the preliminary modeling step P2. As a specific trimming technique, for example, the raw material W is sandwiched by a pair of opposed molds D3, and the unnecessary portion a is trimmed by an FB processing machine. And such a trim promotes the material flow in the final modeling step P4, and makes it easier to realize a near net shape state. In other words, if the raw material W is used as it is in the final modeling process P4 without cutting off the burrs generated in the pre-modeling process P2, the burrs or the like may obstruct the material flow. Since the plastic deformation property (plastic fluidity) itself is low, it may be difficult to form the preform W in a near net shape state.

In the present embodiment, trimming is performed after the final modeling, and when these two trim operations are distinguished, the trim performed immediately before the final modeling is the intermediate trim process P3, and the trimming performed after the final modeling is final. Trimming process P5.
Thus, in the present embodiment, trimming (intermediate trim) is performed before the final modeling step P4. In general, when multiple forgings are performed, trimming is performed only once at the stage where the final forging process is completed, and a near-net-shaped semi-finished product (raw material W) is often obtained.
In the intermediate trim, burrs and the like that have expanded in the direction of the pitch L1 in the pre-modeling step P2 are cut out. As a result, this suppresses the expansion of the material in the direction of the pitch L1 in the final modeling step P4. This also contributes to narrowing the pitch L1.

(4) Final modeling process P4 (restriction process)
This process is the final shape finishing (restriction) in the modeling process. In this embodiment, the pair of opposed molds D4 is applied, and the base material W is die forged (modeled) by an FB processing machine. . Specifically, a blade shape that is about 0.05 mm thick on one side formed in the pre-modeling step P2 is formed by setting the final product shape, and the flange portion 13 and the shaft portion 12 are also formed. The position degree between 12 and the blade shape is secured (corrected).

(5) Final trim process P5 (trim / separate process)
For example, as shown in FIG. 4, this step is a step of cutting away a non-product part b such as a burr protruding from the product part (final product shape) by the final shaping process P4. As a specific processing method, for example, the raw material W is sandwiched between a pair of opposed molds D5, and the non-product part b is trimmed by an FB processing machine. In this embodiment, as shown in FIGS. 4 and 7, the final trimming process P5 also separates the shaped material W from the strip material S (crosspiece member B). Is essentially a trim / separate process.

  Normally, when such separation or the like is performed by press working, a punch (cutting blade) bites into the shearing surface (here, the end of the long shaft portion 12a), as shown in the enlarged view of FIG. Some sag deformation (sag due to pressing) is caused by the cutting. For this reason, in this embodiment, a length obtained by adding a sagging dimension to the actual shaft length (long shaft portion 12a) in advance so that the sagging deformation in the final trimming step P5 does not appear in the variable blade 1 as the final product. The shaft end is separated by the length. That is, since such sagging deformation is unavoidable in press working, in this embodiment, sagging deformation is caused in the non-product portion beyond the actual long shaft portion 12a, and the subsequent cutting process is performed. In P6, the sagging deformation is removed (see FIG. 8). Of course, in this case, blanking is performed in a shape in which the length of the long shaft portion 12a is previously extended from the initial blanking.

  In addition to this, in the present embodiment, as described above, the guide 16 is formed by concentrating the reference surface 15 at the end position of the actual long shaft portion 12a. This makes it easy to fit into one fitting member (the above-described passive element 32B) and improves the assemblability. The guide 16 may be formed only in the long shaft portion 12a because the long shaft portion 12a is press-fitted into the passive element 32B. That is, when the variable wing 1 is fitted into the passive element 32B, the tip (reference surface 15) of the long shaft portion 12a is fitted into the hole of the passive element 32B while applying a force. Providing the guide 16 is extremely effective in improving assemblability. However, since the other short shaft portion 12b is merely fitted into the receiving hole 25 of the holding member 22 in a loosely fitted state, even if there is no particular guide for fitting, it does not contribute so much to improve the assembling property.

Further, the cross section of the shaft portion 12 trimmed in this step is an oval shape as shown in FIG. This is because the fracture surface (cut surface) by trim becomes straight. That is, the major axis of the oval cross section is the direction in which the opposing mold D5 is sandwiched in the final trimming step P5 and the like, and the minor axis of the oval section is the direction orthogonal to this direction (the sandwiching direction of the opposing mold D5). Note that the length of the minor axis of the oval cross section (the trimming width of the shaft portion 12) can be trimmed aiming at the shaft diameter in the finished product state.
In addition, the trimmed shaft portion 12 having an oval cross section is processed into a circle in the subsequent cutting step P6, that is, strictly speaking, the cutting allowance is large in the major axis direction and the minor axis direction in the shaft portion 12 cross section. Is different.

(6) Cutting process P6
This step is a step of cutting mainly the shaft portion 12 of the raw material W after the above-described progressive processing is completed. In this cutting process P6, (i) shaft end face cutting, (ii) shaft center processing, and (iii) shaft / blade processing are performed, and each step will be described below.
(I) Shaft end face cutting This stage is a stage in which both end portions of the shaft portion 12 are cut to ensure the lengths of the long shaft portion 12a and the short shaft portion 12b (final product length). As shown in FIG. 2, the shaped material W after the final trimming is passed between a pair of rotating end mills EM, and the end surfaces of both shaft portions 12 are cut. At this time, the reference of the length of the long shaft portion 12a and the short shaft portion 12b is the end surface of the wing portion 11 (the seat surface of the flange portion 13). At the stage of cutting the shaft end face, the sagging deformation of the long shaft portion 12a is removed as described above, the narrowest portion of the reference surface 15 is cut, and a guide 16 is formed at the shaft end portion.
In the present embodiment, the long shaft portion 12a and the short shaft portion 12b are shown to be cut at the same time, but the end face cutting may be performed one by one in order.

(Ii) Shaft center machining This stage is a stage in which the centers of both shaft portions 12 of the shaped material W whose both end faces are cut to a predetermined length are machined. Then, drilling is performed at this core position. For example, as shown in FIG. 9, a pair of chucking 45 having a V-shaped clamping portion is applied, and the circular arc surfaces (non-trimmed surfaces) of both shaft portions 12 are respectively sandwiched by the chucking 45. In addition, the center position of the chucking 45 (clamping section) is detected as the center position of the shaft section 12, and drilling is performed at this position. The reason why the circular arc surface (non-trimmed surface) of the shaft portion 12 is sandwiched by the chucking 45 is that an accurate center position may not be detected when a planar trim surface is sandwiched.

(Iii) Shaft / blade machining At this stage, for example, as shown in FIG. 10, the base material W (variable blade 1) is rotated while the drilled shaft portions 12 (center position) are held by the core presser 46. Thus, the shaft portion 12 and the blade portion 11 are cut by the cutting tool CT. At this time, the shaft portion 12 is cut by a radius of about 0.15 mm as an example, that is, a shaft diameter of about 0.3 mm. By cutting here, the shaped member W is finished with the blade width h, the shaft diameter, the coaxiality of both shaft portions, etc. as the variable blade 1.

Incidentally, since the shaft portions 12 are formed on both sides of the wing portion 11 in the present embodiment, strictly speaking, if the axial centers of the long shaft portion 12a and the short shaft portion 12b are shifted, the variable wing 1 is assembled as an assembly. In this state, a smooth rotation state cannot be obtained. However, in reality, as described above, since the shaft portion 12 is cut and finished to the final product dimensions, if the misalignment of the shaft cores of the both shaft portions 12 up to the final modeling step P4 is within this cutting allowance. The axial centers of both shaft portions 12 can be matched by cutting. In other words, if the misalignment of the shaft core in the final shaping process P4 is within the cutting allowance dimension, the misalignment of the shaft core can be corrected by the final cutting.
Further, in this stage of cutting, a sliding step 14 is secured on both shaft portions 12, which becomes a sliding surface with reduced frictional resistance, and when the variable blade 1 is assembled as an assembly, a smooth rotating state is realized. .

(7) Barrel Polishing Step This step is a step of polishing the entire surface of the variable wing 1 (raw material W) that has finished the cutting step P6. For example, the variable wing 1 and an additive called a medium are removed from the barrel container. The surface of the variable wing 1 is finished by causing the variable wing 1 and the medium to collide with each other by rotating or vibrating the barrel container.

FIG. 4 is a perspective view (a) showing an example of a VGS type turbocharger incorporating variable blades according to the present invention, and an exploded perspective view (b) showing an example of an exhaust guide assembly. It is the front view of the variable wing | blade which concerns on this invention, the left view, and the right view. It is explanatory drawing which shows a mode that a strip material is supplied with respect to the opposing type | mold of each process provided continuously, and a progressive process is performed. It is explanatory drawing which shows the strip material in which the progressive process was performed in steps in planar view. It is the perspective view (a) which shows a mode that the raw material used as the original form of a variable wing | blade is blanked from a strip material, and the perspective view (b) which shows a general blank method. Explanatory drawing (a), (b) which shows the press metal mold | die which formed the oil drain hole in the opposing bag-shaped part, and explanatory drawing (c) which shows the mode of shaping | molding in a bag-shaped part when not forming an oil drain hole It is. It is a perspective view which shows the mode of each part of the raw material cut | disconnected from the strip material. It is a perspective view which shows a mode that the long-axis part and short-axis part of the raw material cut | disconnected from the strip material are cut. It is explanatory drawing which shows a mode that the axial center of each axial part is detected after cutting the edge part of both axial parts. It is explanatory drawing which shows a mode that after drilling to the center position of both shaft parts, cutting with a bite is hold | maintained, and a shaft diameter, a sliding level | step difference, and a blade width are finished, hold | maintaining this position.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Variable wing | blade 2 Turbine frame 3 Variable mechanism 11 Blade | wing part 11a Leading edge 11b Trailing edge 12 Shaft part 12a Long shaft part 12b Short shaft part 13 ridge part 14 Sliding level | step difference 15 Reference surface 16 Leading-in 17a Thickening recessed part 17b Depression 21 Frame segment 22 Holding member 23 Flange part 23A Flange part (small)
23B Flange (Large)
24 Boss part 25 Receiving hole 26 Caulking pin 27 Pin hole 31 Rotating member 32 Transmission member 32A Drive element 32B Passive element 33 Ring 41 Bag-shaped part 42 Oil drain hole 43 Spherical diameter hole 45 Chucking 46 Core retainer a Unnecessary part b Non-product part h Blade width A Exhaust guide assembly B Crosspiece D1 Opposite type (blank removal)
D2 Opposite type (pre-modeling)
D3 Opposite type (intermediate trim)
D4 Opposite type (final modeling)
D5 Opposite type (final trim)
G Exhaust gas L Blade chord length L1 Pitch O Lubricant P1 Shape preparation process P2 Pre-formation process P3 Intermediate trim process P4 Final shaping process P5 Final trim process P6 Cutting process S Strip material T Exhaust turbine W Shape material CT Byte EM End mill UC Uncoiler LV Leveler PH Pilot hole SC Scrap

Claims (5)

It includes a shaft portion serving as a rotation center and a wing portion that substantially adjusts the flow rate of exhaust gas,
A relatively small amount of exhaust gas discharged from the engine is appropriately throttled, the speed of the exhaust gas is amplified, the exhaust turbine is rotated by the energy of the exhaust gas, and air that exceeds natural intake is sent to the engine by a compressor directly connected to this exhaust turbine. When manufacturing variable wings incorporated in a VGS type turbocharger that allows the engine to exhibit high output even at low speeds,
A blank material punched out from a metal material having a substantially constant plate thickness so as to have a volume capable of realizing the target variable blade is used as a raw material that is the original shape of the variable blade. When,
The material is sandwiched between a pair of opposed molds, and includes at least a modeling step of forming a wing part, a shaft part, or the like into a desired shape,
In addition, the wing portion has a thick wing shape on the leading edge side and a thin wing-shaped cross section on the trailing edge side,
Furthermore, in performing blank removal in the preparation process of the above-mentioned shaped material,
For the leading edge side of the wall thickness, a meat gathering recess is formed almost in the middle of the front edge, and at the time of subsequent modeling processing, the meat on both ends approaches and finally fills,
On the thin trailing edge side, there is a recess for sinking on both ends, and it is formed in a taper shape that is sufficiently narrower than the wingspan. A method of manufacturing a variable blade in a VGS type turbocharger, wherein a blade portion is blanked in a planar shape forming a desired blade width.   The forming process and the forming process of the forming material are performed by progressive processing in which the forming material in the middle of processing is sequentially connected to a part of the metal plate material, and a part of the metal plate material For the shape material that is connected oppositely, the thick leading edge side and the thin trailing edge side are arranged in a point-symmetrical state, and the edges that are different from each other are directed to the feed direction. The method for manufacturing a variable wing in a VGS type turbocharger according to claim 1, wherein:   The variable wing is of a biaxial type having a long shaft portion and a short shaft portion on both sides of the wing portion, and between the wing portion and the shaft portion, the diameter is larger than the plate thickness of the blank material. The method for manufacturing a variable blade in a VGS type turbocharger according to claim 1, wherein a flange is formed.   When blanking is performed in the raw material preparation step, blanking is performed in a state where the pitch L1 of the raw material connected to the metal plate is as close as possible to the chord length L of the finished variable blade. 4. The method of manufacturing a variable blade in a VGS type turbocharger according to claim 2, wherein the variable wing is used.   A shaft portion serving as a rotation center and a wing portion that substantially adjusts the flow rate of the exhaust gas are provided, and a relatively small amount of exhaust gas discharged from the engine is appropriately throttled to amplify the exhaust gas speed. The exhaust turbine is rotated by the energy of the engine, and air that exceeds natural intake air is sent to the engine by a compressor directly connected to the exhaust turbine, so that the engine can deliver high output even at low speeds. A variable wing manufactured by the manufacturing method according to claim 1, 2, 3, or 4.

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