JP2018158373A - Method for manufacturing piping component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a piping component which suppresses a damage by concentration of stress.SOLUTION: A method for manufacturing a common rail (piping component) having a central flow channel and a branch flow channel branched from the central flow channel formed therein includes a forging step and a removal step. The forging step includes forging a base material 50 having a solid rod shape to mold a forged product 60. The forged product 60 has a central forged part 61 being a portion corresponding to a central piping part, a branch forged part 62 being a portion corresponding to a branch piping part, and a dummy forged part 63. The dummy forged part 63 has a shape projecting from the central forged part 61, and is positioned on an opposite side to the branch forged part 62 with respect to the central forged part 61. The removal step includes removing the dummy forged part 63 from the forged part 60.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a method for manufacturing a piping component.

  2. Description of the Related Art Conventionally, there has been known a technique for forging a piping component for circulating a high-pressure fluid such as high-pressure fuel or hydraulic oil. For example, in Patent Document 1, a body of a fuel injection valve that injects high-pressure fuel is manufactured as a piping component by forging a solid rod-shaped base material and drilling the forged product to form a flow path. A method is disclosed.

JP 2006-181577 A

  Here, the present inventors examined the production of piping parts having the structure described below by forging as described above. This piping component includes a central piping portion and a branch piping portion having a shape protruding from the central piping portion in a direction crossing the longitudinal direction of the central piping portion. A central flow path extending in the longitudinal direction is formed inside the central piping section, and a branch flow path branched from the central flow path is formed inside the branch piping section.

  In this type of structure, there is a concern about stress concentration due to the pressure of the high-pressure fluid at a portion (intersection) where the central channel and the branch channel intersect. Therefore, it is necessary to set the shape and thickness of the intersection so that the intersection is not damaged due to stress concentration. However, the present inventors have found that when manufactured by forging as described above, the intersection is actually more likely to be damaged than expected from the stress distribution by numerical analysis.

  The present invention has been made in view of the above problems, and an object thereof is to provide a method for manufacturing a piping component in which damage due to stress concentration is suppressed.

  The invention disclosed herein employs the following technical means to achieve the above object. Note that the reference numerals in parentheses described in the claims and in this section indicate the correspondence with the specific means described in the embodiments described later, and do not limit the technical scope of the invention. .

The disclosed invention
A central pipe section (11) having a central flow path (11a) extending in a predetermined longitudinal direction for circulating fluid;
A pipe having a shape protruding from the central pipe part in a direction intersecting with the longitudinal direction and having a branch pipe part (12) formed therein at least part of the branch flow path (12a) branched from the central flow path A method for manufacturing a component (10), comprising:
A preparation step (S3) in which a solid bar-shaped base material (50) extending in the longitudinal direction is disposed in a forging die (20, 30, 200, 300);
A die is forged by forging a base metal and has a central forged portion (61) that is a portion corresponding to the central piping portion and a branched forged portion (62, 620) that is a portion corresponding to the branched piping portion. A forging step (S4) for forming a forged product (60, 600, 601);
A drilling step (S7) for drilling a forged product to form a central channel and a branch channel;
With
In the forging process, a dummy forging portion (63, 630, 631, 632, 633) that protrudes from the central forging portion in a direction intersecting the longitudinal direction and is located on the opposite side of the branch forging portion with respect to the central forging portion. Forged so that the
It is a manufacturing method of piping components further provided with the removal process (S6) which removes a dummy forge part after a forge process.

  As described above, when a pipe part is manufactured by forging, the intersection is actually more easily damaged than expected from the stress distribution by numerical analysis. About the cause, the present inventors obtained the knowledge demonstrated below.

  The forging base material contains oxides such as calcium oxide and manganese oxide, and elements such as carbon, phosphorus and sulfur as impurities. When the base material has a solid bar shape extending in a predetermined longitudinal direction, impurities may be distributed (center segregation) along the center line of the base material. This phenomenon occurs as follows in the cooling process when casting the base material. In the above cooling process, the iron component contained in the base material is cooled and solidified in order from the outer surface toward the center, whereas the impurity contained in the base material is solidified in order from the outer surface. It is pushed away and moves to the center. Thus, when the cooling in casting is completed, the impurities may segregate at the center.

  When the dummy forged portion is not provided in the forged product, contrary to the above invention, most of the center segregated impurities are located in the central flow path and are removed from the forged product. However, because the piping component has a shape having a branch piping portion protruding from the central piping portion, the base material to be forged is plastically deformed so as to extend from the central forging portion toward the branch forging portion. . Therefore, the distribution of the impurities segregated at the center spreads from the central forging portion to the branch forging portion with plastic deformation of the base material. Impurities distributed in such a widened position are present at positions outside the central flow path, and may remain without being removed from the forged product. And if the remaining impurities are located at the intersection of the central channel and the branch channel, the strength of the intersection will be lower than expected.

  Based on this knowledge, in the above-mentioned invention, in the forging process, a dummy forging part is provided on the opposite side of the branch forging part with respect to the central forging part, and the dummy forging part is removed in the subsequent removal process. Therefore, the base material to be forged is plastically deformed so as to extend from the central forged portion toward the branch forged portion, and at the same time, is plastically deformed so as to extend from the central forged portion toward the dummy forged portion. Therefore, the distribution of the center segregated impurities spreads from the central forging portion to the branch forging portion along with the plastic deformation of the base material, and also to the dummy forging portion. And since a dummy forge part is located in the other side of a branch forge part with respect to a center forge part, the range where an impurity spreads toward a branch forge part spreads an impurity also to the opposite side (dummy forge part side). It is reduced by this. Thereby, since the possibility that impurities spread to the branch forging portion side and reach the intersection can be reduced, damage to the intersection due to stress concentration can be suppressed.

The front view of the common rail manufactured by the manufacturing method which concerns on 1st Embodiment of this invention. II-II sectional drawing of FIG. The flowchart which shows the procedure of the manufacturing method which concerns on 1st Embodiment. The top view explaining the manufacture situation in each process of FIG. Sectional drawing of the metal mold | die for intermediate molding which concerns on 1st Embodiment. It is sectional drawing which follows the VI-VI line of FIG. 4, Comprising: Sectional drawing of the metal mold | die for final shaping | molding which concerns on 1st Embodiment. It is sectional drawing explaining the manufacture condition in each process of FIG. 3, Comprising: The figure which shows the difference of 1st Embodiment and a comparative example about the positional relationship of the impurity and the forging which were center-segregated. Sectional drawing which shows the forged product which concerns on 2nd Embodiment of this invention. The front view of the common rail manufactured by the manufacturing method which concerns on 3rd Embodiment of this invention. Sectional drawing of the forged product which shows the modification with respect to 1st Embodiment.

  Hereinafter, a plurality of modes for carrying out the invention will be described with reference to the drawings. In each embodiment, portions corresponding to the matters described in the preceding embodiment may be denoted by the same reference numerals and redundant description may be omitted. In each embodiment, when only a part of the configuration is described, the other configurations described above can be applied to other portions of the configuration.

(First embodiment)
The piping component shown in FIG. 1 is a common rail 10 provided in an internal combustion engine for a vehicle. The internal combustion engine is a compression self-ignition type having a plurality of cylinders, and the fuel supplied to the common rail 10 is light oil. The common rail 10 accumulates fuel, which is a high-pressure fluid discharged from a high-pressure pump, and distributes the fuel to fuel injection valves provided in each cylinder. The common rail 10 is fixed to a predetermined part in the engine room of the vehicle by a clamp (not shown).

  The common rail 10 is made of metal including a central pipe portion 11 and a branch pipe portion 12. The central piping portion 11 and the branch piping portion 12 are made of metal integrally formed by forging.

  The central piping part 11 has a cylindrical shape extending in a predetermined longitudinal direction (vertical direction in FIG. 1), and a central flow path 11 a extending in the longitudinal direction is formed inside the central piping part 11. The central flow path 11 a has a circular cross-sectional shape that penetrates the central piping part 11. The cross-sectional shape of the central channel 11a in a plane perpendicular to the longitudinal direction is uniform in the longitudinal direction. The central axis A1 of the central piping part 11 and the central axis of the central flow path 11a coincide.

  The branch pipe part 12 has a cylindrical shape protruding from the central pipe part 11 in a direction crossing the central axis A1 of the central pipe part 11, and a plurality of branch pipe parts 12 are provided. In the example shown in FIG. 1, the center axis A <b> 2 of the branch pipe part 12 is orthogonal to the center axis A <b> 1 of the center pipe part 11. A part of the branch flow path 12a branched from the central flow path 11a is formed inside the branch pipe section 12. The branch flow path 12 a has a circular cross section that penetrates the branch pipe portion 12. The central axis A2 of the branch pipe portion 12 and the central axis of the branch flow path 12a coincide. A portion of the branch channel 12a that communicates with the central channel 11a is referred to as a pore channel 12b, and a portion of the branch channel 12a that has the pore channel 12b has a channel cross-sectional area as compared with the other portions. small. The pore channel 12 b is located inside the central piping part 11.

  The central flow path 11a and the branch flow path 12a are filled with high-pressure fuel supplied from a high-pressure pump. Specifically, the high-pressure fuel discharged from the high-pressure pump first flows into the central flow path 11a, and then is distributed to each branch flow path 12a. The high-pressure fuel throttled in the pore channel 12b of the branch channel 12a is supplied to the fuel injection valve through a high-pressure pipe (not shown) connected to the branch pipe unit 12.

  As shown in FIG. 2, a portion of the central piping portion 11 where the central flow path 11a and the branch flow path 12a intersect is referred to as an intersecting portion 11p. In addition, the inner wall surface of the intersecting portion 11p has a circular edge shape when viewed from the central flow path 11a side to the branch flow path 12a side in the direction of the central axis A2. In the example shown in FIG. 2, the intersecting portion 11 p has an edge shape having a wall surface having a right-angle cross section.

  As shown in FIGS. 1 and 2, the plurality of branch pipe portions 12 are located on the same side (the right side in FIG. 2) with respect to a predetermined reference plane B1. The reference plane B1 is a plane that includes the central axis A1 of the central pipe portion 11 and is orthogonal to the central axis A2 of the branch pipe portion 12. The central axes A2 of the plurality of branch pipe portions 12 are located on the same plane, and the central axes A2 of the plurality of branch pipe portions 12 are parallel to each other. The plurality of branch pipe portions 12 are arranged at an equal pitch in the longitudinal direction.

  Next, a method for manufacturing the common rail 10 will be described with reference to FIGS. 4 is a plan view showing the lower die 20 of the forging die, (2) is a plan view in which the base material 50 is disposed on the lower die 20, and (3) is a column. It is a top view which shows 60 A of forgings immediately after demolding. 4 is a plan view showing the forged product 60 in a state in which the forging burr 60x is removed from the forged product 60A. The common rail 10 shown in FIG. 1 is manufactured from the forged product 60.

  First, in step S <b> 1 shown in FIG. 3, a cylindrical steel material that is a base material of the common rail 10 is cut into a predetermined length. In the subsequent step S2, the steel material (base material) cut in the step S1 is heated to a predetermined temperature. This predetermined temperature is set to a temperature (for example, several hundred degrees) at which the base material is recrystallized. In the subsequent step S3 (preparation step), the base material 50 heated in step S2 is placed in the forging die (lower die 20) shown in FIG. 4 (1) (see FIG. 4 (2)). .

  Strictly speaking, in this embodiment, forging is performed step by step using two types of molds. First, after forging with an intermediate molding die shown in FIG. 5, the final molding die shown in FIG. Forging with a mold.

  These molds include lower molds 20 and 200 and upper molds 30 and 300. Lower cavities 20a and 200a are formed in the lower molds 20 and 200, and upper cavities 30a and 300a are formed in the upper molds 30 and 300. In step S3, the upper molds 30 and 300 are installed at positions immediately above the base material 50 disposed in the lower molds 20 and 200 so that the upper cavities 30a and 300a are positioned immediately above the lower cavities 20a and 200a.

  In the forging related to the intermediate forming and the forging related to the final forming, although dies having different cavity shapes are used, the manufacturing procedure is the same. Therefore, in the description of FIG. The mold for final molding will be described with the mold omitted. In carrying out the present invention, forging may be performed with a final molding die without using an intermediate molding die.

  In the subsequent step S4 (forging step), the upper die 30 is hit with a hammer of a forging press, and the base material 50 is pressed between the upper die 30 and the lower die 20. Thereby, the base material 50 is plastically deformed following the shape of the cavities 20a and 30a.

  In the subsequent step S5, the upper mold 30 and the lower mold 20 are removed, and the forged product 60A shown in the column (3) of FIG. 4 is taken out. The forged product 60A immediately after demolding has a central forged portion 61, a branched forged portion 62, a dummy forged portion 63, and a forged burr 60x. The central forging portion 61 is a portion corresponding to the central piping portion 11 of the common rail 10. The branch forging portion 62 is a portion corresponding to the branch piping portion 12 of the common rail 10, and a plurality of branch forging portions 62 are provided in the same manner as the branch piping portion 12. The dummy forged portion 63 has a cylindrical shape that protrudes from the central forged portion 61 in a direction intersecting with the longitudinal direction, and is located on the opposite side of the branch forged portion 62 with respect to the central forged portion 61.

  Here, each of the lower cavity 20a and the upper cavity 30a shown in FIG. 6 forms the central parts 21, 31 for forming the central forged part 61, the branch parts 22, 32 for forming the branched forged part 62, and the dummy forged part 63. Dummy portions 23 and 33 are provided. The upper half of the central forged portion 61, the branch forged portion 62 and the dummy forged portion 63 is forged with the upper die 30, and the lower half is forged with the lower die 20. A portion of the base material 50 that protrudes from between the lower die 20 and the upper die 30 becomes a forged burr 60x. In step S <b> 3, the base material 50 is placed in the mold so that the center axis of the base material 50 coincides with the center axes of the central portions 21 and 31.

  Returning to the description of the forged product 60, a plurality of dummy forged portions 63 are provided corresponding to each of the branch forged portions 62, and the number of dummy forged portions 63 and the number of branch forged portions 62 are the same. As shown in the column (4) of FIG. 4, each dummy forged portion 63 is arranged so that the central axis A2 of the branch forged portion 62 and the central axis A3 of the dummy forged portion 63 coincide.

  The dummy forged portion 63 and the branched forged portion 62 are cylindrical and have the same shape. Further, the size of the dummy forged portion 63 is the same as the size of the branch forged portion 62. Therefore, the volume of the dummy forging part 63 is the same as the volume of the branch forging part 62. The volume of the dummy forging part 63 defined here is the volume of the part obtained by removing the cylindrical central forging part 61 from the forging 60 together with the branch forging part 62. Moreover, the volume of the branch forging part 62 defined here is a volume of the part remove | excluding the column-shaped center forging part 61 from the forging 60 with the dummy forging part 63. FIG.

  In the subsequent step S6, the forging burr 60x is removed by trimming, and the forged product 60 shown in the column (4) of FIG. 4 is taken out. Further, in step S6 (removal step), the dummy forging portion 63 is removed together with the forging burr 60x. Specifically, the dummy forging part 63 is removed using a cutting tool such as a lathe. In the subsequent step S7 (drilling step), the forged product 60 is drilled to form the central channel 11a and the branch channel 12a.

  In the subsequent step S8, chamfering is performed on the tip of the branch piping part 12 and both ends of the central piping part 11 to remove burrs generated in the drilling process in step S7. Thereby, the common rail 10 is manufactured from the forged product 60. That is, one common rail 10 is manufactured from one base material 50.

  Note that a pump pipe, a distribution pipe, a pressure sensor, and the like (not shown) are attached to the common rail 10 shown in FIG. The pump pipe is a pipe that is connected to the high-pressure pump and the common rail 10 described above and supplies the fuel discharged from the high-pressure pump to the common rail 10. For example, the pump pipe is attached to one end of the central pipe portion 11. The distribution pipe is a pipe that is connected to the fuel injection valve and the common rail 10 described above, distributes and supplies fuel from the common rail 10 to the fuel injection valve, and is attached to the branch pipe portion 12. The pressure sensor is a sensor that detects the fuel pressure in the common rail 10, and is attached to the other end of the central pipe portion 11, for example.

  Next, the above-described impurity IP contained in the base material 50 will be described below with reference to FIGS. 4 and 7. The halftone dots in the figure indicate the distribution range of the impurity IP. The illustrated distribution range indicates a range in which impurities are present at a predetermined concentration or higher, and the impurity IP may be present at a concentration lower than the predetermined concentration even outside the distribution range.

  7 is a cross-sectional view of the base material 50 immediately before forging, FIG. 7 (2) is a cross-sectional view of the forged product 60A shown in FIG. 4 (2), and FIG. 7 (3). The column is a cross-sectional view of the forged product 60 with the forged burr 60x and the dummy forged portion 63 removed. 7 (4) and (5) are sectional views showing forged products 60AR and 60R as comparative examples of the present embodiment. In this comparative example, the dummy forging part 63 is not provided contrary to this embodiment, and it is forged from the base material 50 of the same shape as this embodiment. The forged product 60AR shown in the column (4) of FIG. 7 has a central forged portion 61R, a branched forged portion 62R, and a forged burr 60x. The forged product 60R shown in the column (5) of FIG. 7 is a state in which the forged burrs 60x are removed from the forged product 60AR.

  As shown in the column (2) of FIG. 4 and the column (1) of FIG. 7, the impurity IP at the time before forging is distributed (center segregation) at the center of the cross section of the base material 50. The distribution range is a range that extends in a perfect circle from the cross-sectional center of the base material 50. In addition, the reference plane B1 indicated by the alternate long and short dash line in the drawing is a plane that includes the central axis A1 of the base material 50 and is orthogonal to the mold dividing plane C1 (see FIG. 6). It is also a reference plane B1 including the central axis A1, and coincides with the reference plane B1 shown in FIG.

  As shown in the column (3) of FIG. 4 and the column (2) of FIG. 7, the distribution of the impurity IP contained in the forged product 60A spreads in the direction of deformation as the base material 50 is plastically deformed by forging. Yes. The distribution range is a range that expands in an elliptical shape from the cross-sectional center of the base material 50. Therefore, the elliptical longitudinal direction of the distribution range coincides with the protruding direction of the branch forging portion 62 and the dummy forging portion 63. Further, since the impurity IP spreads to both the side from which the branch forging portion 62 projects (the right side in FIG. 7) and the side from which the dummy forging portion 63 projects (the left side in FIG. 7), the distribution center of the impurity IP (the center of the ellipse) However, deviation from the central axis A1 of the central forging portion 61 is suppressed. In the example of the column of FIG. 4 (4), the center of the ellipse coincides with the central axis A1 of the central forged portion 61.

  As shown in FIG. 7 (3), the distribution of the impurity IP contained in the forged product 60 after trimming is the same as the distribution of the impurity IP contained in the forged product 60A before trimming. In other words, the distribution center (center of the ellipse) of the impurity IP coincides with the central axis A1 of the central forged portion 61. In other words, the distribution of the impurity IP contained in the forged products 60A and 60 extends to the target in the protruding direction of the branch forged portion 62 and the dummy forged portion 63 with the reference plane B1 as the center when viewed in the direction of the central axis A1. .

  Thereby, the impurity IP does not exist in the intersection 11p of the common rail 10. More specifically, the impurity IP exists in a portion of the central pipe portion 11 on the side opposite to the branch pipe portion 12 (left side in FIG. 2) with respect to the reference plane B1 when viewed in the direction of the central axis A1. However, the impurity IP does not exist in the central piping portion 11 on the same side (right side in FIG. 2) as the branch piping portion 12 with respect to the reference plane B1.

  On the other hand, since the forged product 60AR of the comparative example does not include the dummy forged portion 63, as shown in the column (4) of FIG. 7, the impurity IP is large toward the side where the branch forged portion 62R protrudes (the right side in FIG. 7). While expanding, it does not expand greatly to the opposite side (left side of FIG. 7). For this reason, the distribution center (center of the ellipse) of the impurity IP greatly deviates from the central axis A1 of the central forging portion 61R toward the branch forging portion 62R.

  Therefore, as for the distribution of the impurity IP contained in the forged product 60R after trimming, as shown in the column (5) of FIG. 7, the distribution center of the impurity IP (the center of the ellipse) is from the central axis A1 of the central forged portion 61R. It is greatly displaced toward the branch forging portion 62R. In other words, the distribution of the impurity IP contained in the forged products 60AR and 60R is spread toward the branch forged portion 62R side with respect to the reference plane B1 when viewed in the direction of the central axis A1. Therefore, when a common rail is manufactured from the forged product 60R of the comparative example, the probability that the impurity IP exists at the intersection of the common rail is increased.

  Next, the function and effect of this embodiment will be described.

  In the above-described embodiment, the central pipe portion 11 having the central flow passage 11a formed therein, and a shape protruding from the central pipe portion 11 and a part of the branch flow passage 12a formed therein, the branch pipe portion 12 Are manufactured as follows. That is, a forged product 60 having a solid bar-shaped base material 50 arranged in a mold and having a central forged part 61 corresponding to the central pipe part 11, a branched forged part 62 corresponding to the branched pipe part 12, and a dummy forged part 63. Is molded. Then, the dummy forged portion 63 is removed after forging, and the common rail 10 is manufactured by drilling the central flow path 11a and the branch flow path 12a. The dummy forged portion 63 has a shape protruding from the central forged portion 61 in a direction intersecting with the longitudinal direction of the central forged portion 61, and is located on the opposite side of the branch forged portion 62 with respect to the central forged portion 61.

  According to this, the base material 50 to be forged is plastically deformed so as to extend from the central forging portion 61 toward the branch forging portion 62, and at the same time, is plastic so as to extend toward the dummy forging portion 63 from the central forging portion 61. Deform. Accordingly, the distribution of the impurity IP segregated at the center spreads from the central forging portion 61 toward the branch forging portion 62 along with the plastic deformation of the base material 50 and also at the dummy forging portion 63. And since the dummy forge part 63 is located in the other side of the branch forge part 62 with respect to the center forge part 61, the range which the impurity IP spreads toward the branch forge part 62 is the impurity forge part simultaneously with the expansion. Reduced by expanding to 63. Thereby, since the possibility that the impurity IP spreads to the branch forging part 62 side and reaches the intersecting part 11p can be reduced, damage to the intersecting part 11p due to stress concentration can be suppressed.

  Further, in the present embodiment, the forging is performed so that the branch forging portion 62 and the dummy forging portion 63 overlap with each other in the longitudinal direction of the central forging portion 61. Further, forging is performed so that the central axis A2 of the branch forging portion 62 and the central axis A3 of the dummy forging portion 63 are located on the same plane. Specifically, the branch forging portion 62 and the dummy forging portion 63 have a positional relationship in which the center axis A2 of the branch forging portion 62 and the center axis A3 of the dummy forging portion 63 coincide. According to this, the above-mentioned effect (expansion suppressing effect) that “the range in which the impurity IP expands toward the branch forging portion 62 is reduced by the impurity IP expanding toward the dummy forging portion 63 simultaneously with the expansion”. Becomes prominent. Therefore, the reduction of the range in which the impurity IP extends to the branch forging part 62 side is promoted, and the reduction of the possibility that the impurity IP reaches the intersecting part 11p can be promoted.

  Further, in the present embodiment, all of the plurality of branch forging portions 62 are arranged on one side (the right side of the column (2) in FIG. 7) with respect to a predetermined reference plane B1 including the central axis A1 of the central forging portion 61. ing. Further, all of the plurality of dummy forged portions 63 are arranged on the other side (left side in the column (2) in FIG. 7) with respect to the reference plane B1. According to this, since the center segregated impurity IP is attracted to the other side over the entire longitudinal direction of the central forged portion 61, compared with a case where only a predetermined portion in the longitudinal direction is attracted to the other side. The above-described expansion suppression effect can be improved.

  Further, in the present embodiment, a plurality of dummy forging portions 63 are also provided corresponding to each of the branch forging portions 62. Specifically, the dummy forging portions 63 are provided corresponding to all the branch forging portions 62, and the dummy forging portions 63 are provided in the same number as the branch forging portions 62. Therefore, the above-described expansion suppression effect is exerted on all the branch forging portions 62, and the cross portion 11p damage suppression can be promoted.

  Further, in the present embodiment, the forging is performed so that each of the branch forging portions 62 and each of the dummy forging portions 63 overlap with each other in the longitudinal direction of the central forging portion 61. Specifically, the central axis A <b> 3 of all the dummy forged parts 63 coincides with the central axis A <b> 2 of the branch forged part 62. According to this, the expansion suppression effect can be promoted with respect to all the branch forging portions 62, and the cross portion 11p damage suppression can be promoted.

  Furthermore, in this embodiment, the volume of the dummy forging part 63 is 62 volumes or more of the branch forging part. That is, the volume of the dummy forged portion 63 corresponding to any one branch forged portion 62 is equal to or greater than the volume of the corresponding branched forged portion 62. Specifically, the dummy forging part 63 has the same volume as the branch forging part 62. According to this, compared with the case where the volume of the dummy forging part 63 is smaller than the volume of the branch forging part 62, the above-described expansion suppressing effect becomes remarkable, so that the range in which the impurity IP expands to the branch forging part 62 side is reduced. It is possible to promote the reduction of the possibility that the impurity IP reaches the intersection 11p.

  Moreover, since each dummy forging part 63 is more than the volume of the corresponding branch forging part 62, and the dummy forging part 63 is provided with the same number as the branch forging part 62, the total volume of several dummy forging part 63 is provided. However, it is more than the total volume of the plurality of branch forging parts 62. According to this, compared with the case where the total volume of the dummy forged portion 63 is smaller than the total volume of the branch forged portion 62, the above-described expansion suppression effect becomes remarkable, so that the range of the impurity IP to expand toward the branch forged portion 62 side. Reduction can be promoted.

(Second Embodiment)
In the first embodiment, as shown in the columns (2) and (3) of FIG. 7, all of the plurality of branch forging portions 62 are on one side with respect to the reference plane B1 including the central axis A1 of the central forging portion 61. All of the plurality of dummy forged portions 63 are arranged on the other side with respect to the reference plane B1. On the other hand, in this embodiment, as shown in FIG. 8, a specific branch forging portion 620 among the plurality of branch forging portions 62 and 620 is opposite to the other branch forging portions 62 with respect to the reference plane B1. It is arranged on the side (the other side). Accordingly, the dummy forged portion 630 corresponding to the specific branch forged portion 620 is disposed on the side (one side) opposite to the dummy forged portion 63 corresponding to the other branch forged portion 62. In short, the branch forging part 62 and the dummy forging part 630 are mixedly arranged on one side with respect to the reference plane B1, and the branch forging part 620 and the dummy forging part 63 are also arranged on the other side with respect to the reference plane B1. Are mixed and arranged.

  Also in this embodiment, the central axis A2 of the branch forging portions 62 and 620 and the central axis A3 of the dummy forging portions 63 and 630 are located on the same plane as in the first embodiment. Further, the central axes A2 and A3 are located on the same plane for all of the plurality of branch forging portions 62 and 620 and the plurality of dummy forging portions 63 and 630.

  Moreover, the branch forging part 62 and the dummy forging part 630 arrange | positioned at one side are arrange | positioned at equal pitch in the longitudinal direction. The branch forging portions 620 and the dummy forging portions 63 arranged on the other side are arranged at an equal pitch in the longitudinal direction.

  The procedure of the manufacturing method according to the present embodiment is the same as the procedure of the first embodiment shown in FIG. 3, and a forged product 601 including a central forged portion 61, branch forged portions 62 and 620 and dummy forged portions 63 and 630 is provided. Forging. Thereafter, the dummy forged portions 63 and 630 are removed together with the forged burrs 60x, and drilling is performed to manufacture the common rail 10.

  As described above, also in the present embodiment in which the branch forging portions 62 and 620 protruding to different sides with respect to the reference plane B1 are provided, the branch forging portions 62 and 620 are on the opposite side of the central forging portion 61. Dummy forging parts 63 and 630 are provided. Accordingly, as in the first embodiment, “the range in which the impurity IP expands toward the branch forging portions 62 and 620 is reduced by the impurity IP expanding toward the dummy forging portions 63 and 630 simultaneously with the expansion. The above-mentioned effects such as "" are exhibited. Therefore, the possibility that the impurity IP reaches the intersection 11p can be reduced.

(Third embodiment)
As shown in FIG. 9, the common rail 100 manufactured by the manufacturing method according to this embodiment includes a mounting boss 14. A through hole 14a is formed in the mounting boss 14, and a bolt (not shown) is inserted into the through hole 14a. The common rail 100 is fixed to a predetermined part of the vehicle by fastening the bolt to the predetermined part of the vehicle. .

  Accordingly, a forged product (not shown) that is a precursor of the common rail 100 is a portion corresponding to the mounting boss 14 in addition to the central forged portion 61, the branch forged portion 62, and the dummy forged portion 63 similar to those of the first embodiment. A certain forging part (not shown) is provided. The attachment forging portion is located on the opposite side of the branch forging portion 62 with respect to the central forging portion 61. The attachment forging portion and the branch forging portion 62 have a positional relationship overlapping in the longitudinal direction.

  About the branch forge part 62 and attachment forge part which become the positional relationship of duplication, the volume of an attachment forge part is more than the volume of the branch forge part 62. Further, the total volume of the plurality of attachment forging portions and the dummy forging portion 63 is equal to or greater than the total volume of the plurality of branch forging portions 62. Further, the central axis A2 of the branch forging portion 62 and the central axis A4 (see FIG. 9) of the attachment forging portion are located on the same plane. Further, the total number of dummy forged portions 63 and the number of attached forged portions is the same as the number of branch forged portions 62.

  In short, in the forged product 60 according to the first embodiment, the forged product of the present embodiment is obtained by replacing the two dummy forged parts 63 with the attached forged parts. In the present embodiment, the dummy forged portion 63 is removed after forging, but the mounting forged portion is not removed but the through hole 14a is formed as the mounting boss 14. However, the dummy forged portion 63 has a cylindrical shape, whereas the attached forged portion has a plate shape.

  As described above, also in the present embodiment in which the mounting boss 14 is formed on the common rail 100, the dummy forging portion 63 or the mounting forging portion is provided on the opposite side of the central forging portion 61 with respect to each of the branch forging portions 62. . Therefore, as in the first embodiment, “the range in which the impurity IP expands toward the branch forging portion 62 is reduced by the impurity IP expanding toward the dummy forging portion 63 or the attachment forging portion simultaneously with the expansion. The effect of “ru” is demonstrated. Therefore, also about the branch piping part 12 of the position corresponding to the attachment boss | hub 14, the possibility that the impurity IP may reach the crossing part 11p can be reduced.

(Modification of the first embodiment)
In the first embodiment, the branch forging portion 62 and the dummy forging portion 63 have a positional relationship that overlaps in the longitudinal direction of the central forging portion 61. Specifically, as shown in the column (4) of FIG. 4, the central axis A2 of the branch forging portion 62 and the central axis A3 of the dummy forging portion 63 coincide with each other. On the other hand, the embodiment described below using the forged product 600 shown in FIG. 10 is arranged so that the central axes A2 and A3 do not coincide with each other even though the overlapping positional relationship is described above. It is a modification with respect to one Embodiment.

  A symbol W in FIG. 10 indicates a projection range of the branch forging portion 62 viewed from the direction of the central axis A2 of the branch forging portion 62. Therefore, the projection range W is also cylindrical with the branch forging part 62 being cylindrical. Reference numerals 63, 631, 632, and 633 in FIG. 10 indicate dummy forged portions that have the above-described overlapping positional relationship. When viewed from the direction perpendicular to both the central axis A1 of the central forged portion 61 and the central axis A2 of the branched forged portion 62, that is, from the direction perpendicular to the plane of FIG. 10, at least a part of the dummy forged portion is within the projection range W. If it exists, it can be said that it is the above-mentioned “overlapping positional relationship”.

  In the dummy forged portion 63, the central axis A2 of the branch forged portion 62 and the central axis A3 of the dummy forged portion 63 coincide with each other in the same manner as in the first embodiment. The entire dummy forging portion 63 is included in the projection range W and overlaps with the branch forging portion 62 in the longitudinal direction of the central forging portion 61.

  In the dummy forged portion 631, although the center axis A <b> 2 of the branch forged portion 62 and the center axis A <b> 3 of the dummy forged portion 63 are shifted, the center axis A <b> 3 of the dummy forged portion 63 is included in the projection range W. Further, more than half of the dummy forged portion 631 is included in the projection range W and overlaps with the branch forged portion 62 in the longitudinal direction of the central forged portion 61.

  In the dummy forged portion 632, although the central axis A3 of the dummy forged portion 63 is not included in the projection range W, a part of the dummy forged portion 632 is included in the projection range W, and in the longitudinal direction of the central forged portion 61, It overlaps with the branch forging part 62.

  The dummy forged portion 633 is disposed across a plurality of projection ranges W. In other words, the dummy forged portion 633 is a composite of a plurality of dummy forged portions 63 shown in the column (4) of FIG. In the example shown in FIG. 10, the dummy forged portion 633 has an elliptical cross section extending in the longitudinal direction of the central forged portion 61 and is disposed across two projection ranges W. The central axis A3 of the dummy forged portion 633 is located between the central axes A2 of the two adjacent branch forged portions 62.

  Any of the dummy forged portions 63, 631, 632, and 633 described above is provided on the opposite side of the central forged portion 61 with respect to the branch forged portion 62, and is removed after forging. Therefore, in the same manner as in the first embodiment, the above-described expansion suppressing effect is exhibited, and the possibility that the impurity IP reaches the intersection 11p can be reduced.

(Other embodiments)
The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made as illustrated below. Not only combinations of parts that clearly show that combinations are possible in each embodiment, but also combinations of the embodiments even if they are not explicitly stated unless there is a problem with the combination. Is also possible.

  In the common rail 10 manufactured by the manufacturing method according to the first embodiment, the impurity IP exists in the central pipe portion 11 on the same side (right side in FIG. 2) as the branch pipe portion 12 with respect to the reference plane B1. do not do. On the other hand, it may be manufactured such that the impurity IP exists in a portion of the central pipe portion 11 on the same side as the branch pipe portion 12 with respect to the reference plane B1. However, it is desirable to manufacture so that the impurity IP does not exist in the intersection 11p.

  The common rail 10 shown in FIG. 1 has a shape in which a plurality of branch piping portions 12 protrude from one central piping portion 11, but may have a shape in which one branch piping portion 12 protrudes. Further, the number of mounting bosses 14 shown in FIG. 9 may be one.

  In each of the above embodiments, the pipe material is manufactured by hot forging by heating the base material as shown in step S2 of FIG. 3, but the pipe part is manufactured by cold forging forging the base material at room temperature. May be. In each of the embodiments described above, the fuel used for combustion is applied as a high-pressure fluid that circulates in the piping components, but hydraulic oil used for a hydraulic actuator or the like may be applied as the high-pressure fluid.

  The common rail 100 shown in FIG. 9 is manufactured from a forged product in which the dummy forged portion 63 of the forged product 60 shown in FIG. On the other hand, this invention is applicable also to the common rail manufactured from the forged product which added the attachment forge part to the forged product 60 shown to the column of FIG. 4 (4).

  In the said 1st Embodiment, although the volume of the dummy forge part 63 is the same as the volume of the branch forge part 62, this invention is not limited to this, The volume of the dummy forge part 63 of the branch forge part 62 is It may be larger or smaller than the volume. When the volumes of the dummy forged portion 63 and the branch forged portion 62 are made different from each other in this way, the length of the dummy forged portion 63 in the central axis A3 direction is made different from the length of the branch forged portion 62 in the central axis A2 direction. Alternatively, the size in the radial direction may be varied.

  In the modification shown in FIG. 10, the central axis A3 of the dummy forged portions 63, 631, 632, 633 is parallel to the central axis A2 of the branched forged portion 62, but may be non-parallel. Further, the central axis A3 of the dummy forged portions 63, 631, 632, and 633 and the central axis A2 of the branch forged portion 62 may not be located on the same plane. In short, the protruding direction of the dummy forged portion from the central forged portion 61 and the protruding direction of the branch forged portion 62 may be different.

  In the first embodiment, the dummy forged portions 63 are provided in the same number as the branched forged portions 62. On the other hand, the number of dummy forged portions 63 may be smaller or larger than the number of branch forged portions 62.

  In the present invention, the central flow path 11a is not limited to being located at the center of the central piping section 11, and may be located off the center. In that sense, the “central flow path” may be referred to as “main passage”, the “central piping portion” may be referred to as “main piping portion”, and may be referred to as “central forging portion” or “main forging portion”.

  DESCRIPTION OF SYMBOLS 10 Piping parts (common rail), 11 Central piping part, 11a Central flow path, 12 Branch piping part, 12a Branch flow path, 50 Base material, 60, 600, 601 Forged product, 61 Central forging part, 62, 620 Branch forging part 63, 630, 631, 632, 633 dummy forging section, S3 preparation step, S4 forging step, S7 drilling step.

Claims (7)

A central pipe section (11) having a central flow path (11a) extending in a predetermined longitudinal direction for circulating fluid;
A branch pipe part (12) having a shape protruding from the central pipe part in a direction intersecting with the longitudinal direction, and at least a part of a branch flow path (12a) branched from the central flow path formed therein; A pipe part (10) manufacturing method comprising:
A preparation step (S3) of disposing the solid rod-shaped base material (50) extending in the longitudinal direction in a forging die (20, 30, 200, 300);
A load is applied to the mold to forge the base material, and a central forging portion (61) that is a portion corresponding to the central piping portion and a branch forging portion (62, which is a portion corresponding to the branch piping portion). 620) forging step (S4) for forming a forged product (60, 600, 601);
A drilling step (S7) for drilling the forged product to form the central channel and the branch channel;
With
In the forging step, a dummy forging portion (63, 630, 631) that protrudes from the central forging portion in a direction crossing the longitudinal direction and is located on the opposite side of the branch forging portion with respect to the central forging portion. 632, 633) are forged so as to be provided in the forged product,
A method for manufacturing a piping component, further comprising a removing step (S6) for removing the dummy forged portion after the forging step.   The method for manufacturing a piping part according to claim 1, wherein in the forging step, forging is performed so that the branch forging portion and the dummy forging portion overlap in the longitudinal direction.   The pipe part manufacturing method according to claim 2, wherein a volume of the dummy forged portion is equal to or greater than a volume of the branched forged portion with respect to the branch forged portion and the dummy forged portion that are in the overlapping positional relationship. The forged product has a shape in which a plurality of branch forged portions and a plurality of dummy forged portions protrude from one central forged portion,
The method for manufacturing a piping component according to any one of claims 1 to 3, wherein a total volume of the plurality of dummy forged portions is equal to or greater than a total volume of the plurality of branched forged portions.   The method for manufacturing a piping component according to any one of claims 1 to 4, wherein in the forging step, forging is performed so that a central axis of the branch forging portion and a central axis of the dummy forging portion are positioned on the same plane. . The forged product has a shape in which a plurality of branch forged portions and a plurality of dummy forged portions protrude from one central forged portion,
All of the plurality of branch forging portions are arranged on one side with respect to a predetermined reference plane (B1) including the central axis of the central forging portion,
The piping part manufacturing method according to claim 1, wherein all of the plurality of dummy forged portions are arranged on the other side with respect to the reference surface. The forged product has a shape in which a plurality of branch forged portions and a plurality of dummy forged portions protrude from one central forged portion,
The said dummy forging part is a manufacturing method of the piping components as described in any one of Claims 1-6 provided with the same number as the said branch forging part.

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