JP2009226410A - Method for manufacturing hollow valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the generation of wrinkles caused by buckling on a thick onion-shape portion formed with a conducting upsetting formation and further, the poor formation of the cap part thereafter. <P>SOLUTION: A method for manufacturing a hollow valve, is performed through the following processes: (1) in the first process, a pipe blank, in which a core material is inserted into only a prescribed length at the one end part, is prepared; (2) in the second process, the one end part of the pipe blank inserted with the core material, is formed into the thick solid onion with the conducting upsetting formation; (3) in the third process, the thick onion is formed into a primary cap part with a hot-forging; (4) in the forth process, the primary cap part is formed into a secondary cap part with a cutting-work; (5) in the fifth process, a cap-edge member is assembled on the cap-edge part with a partial part assembling and a shaft-end member is assembled to the tip-end part of the pipe blank; (6) in the sixth process, the cap-edge member and the shaft-end member, are welded to the pipe blank with the partial-welding; and (7) in the seventh process, the finish-product of the hollow valve is obtained by finish-working the rough-product. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a hollow valve used as an intake valve or an exhaust valve of an engine, and more particularly to a manufacturing method thereof.

  2. Description of the Related Art Conventionally, as an intake valve or exhaust valve for an engine, a hollow valve having a hollow shape including a shaft portion and an umbrella portion formed at one end of the shaft portion is known. As this type of technology, for example, the technologies described in Patent Documents 1 to 4 below are listed. In particular, Patent Document 1 describes a method of manufacturing a hollow valve by energizing upsetting a thin pipe material.

JP 49-79958 A JP-A-7-208127 Japanese Patent Laid-Open No. 48-6966 JP-A-6-335747

  However, in the manufacturing method described in Patent Document 1, when the tip of the pipe material is formed into a thick onion shape by energizing upset, wrinkles due to buckling may occur outside the thick onion portion. . Buckling occurs when the pipe material is compressed in the axial direction and the meat is folded. Therefore, when this thick onion-shaped portion is forged into an umbrella shape, there is a risk that a defect will occur inside. For this reason, there is a possibility that a molding defect may occur during the subsequent molding of the umbrella portion.

  The present invention has been made in view of the above circumstances, and its purpose is to prevent wrinkling due to buckling in a thick onion-shaped portion due to energizing upset molding, and to prevent subsequent molding failure of the umbrella portion. It is an object of the present invention to provide a method of manufacturing a hollow valve that can be performed.

  In order to achieve the above object, the invention described in claim 1 is a method for manufacturing a hollow valve having a shaft portion and an umbrella portion formed at one end of the shaft portion, and having a hollow shape. Inserting a core material into the pipe material by a predetermined length from one end of the material, and forming one end of the pipe material into which the core material is inserted into a thick onion shape by energizing upset The purpose is to have

  According to the configuration of the present invention, the one end of the pipe material into which the core material is inserted is energized upset, so that the one end is formed into a thick onion shape. Here, since the core material is inserted into one end of the pipe material, the thickness of the pipe material is substantially increased by the amount of the core material. Accordingly, the radial deformation is smaller than the deformation of the pipe material in the axial direction during energization upset molding.

  To achieve the above object, the invention described in claim 2 further comprises a step of forming one end portion formed into a thick onion shape into an umbrella shape by hot forging in the invention according to claim 1. The purpose is to prepare.

  According to the configuration of the invention, in addition to the action of the invention of claim 1, one end portion formed into a thick onion shape in the previous step is formed into an umbrella shape by hot forging, and the rough portion of the umbrella portion 3 is formed. Shape is obtained.

  In order to achieve the above object, the invention described in claim 3 is characterized in that, in the invention described in claim 2, further comprising a step of cutting one end portion formed into an umbrella shape into a predetermined shape. To do.

  According to the configuration of the above invention, in addition to the operation of the invention according to claim 2, one end portion formed into an umbrella shape in the previous step is formed into a predetermined shape by cutting.

  In order to achieve the above object, according to a fourth aspect of the present invention, in the third aspect of the present invention, an umbrella end member is assembled to one end portion cut into a predetermined shape, and a shaft is attached to the other end of the pipe material. It is intended to further include a step of assembling the end member.

  According to the configuration of the above invention, in addition to the action of the invention according to claim 3, the umbrella end member is assembled to the one end portion cut into a predetermined shape in the previous step, whereby the one end portion is closed. An umbrella part is constructed. When the shaft end member is assembled to the other end of the pipe material, the other end opening of the pipe material is closed. Thereby, the hollow valve which sealed the inside is obtained. Since the umbrella end member and the shaft end member are assembled separately from the pipe material, it is possible to select a durable material harder than the pipe material as these separate members.

  In order to achieve the above object, a hollow valve according to a fifth aspect of the present invention is manufactured by the method for manufacturing a hollow valve according to the fourth aspect.

  According to the structure of the said invention, the hollow valve | bulb without a shaping | molding defect in an umbrella part is obtained.

  In order to achieve the above object, the invention described in claim 6 is a method of manufacturing a hollow valve having a shaft portion and an umbrella portion formed at one end of the shaft portion, and having a hollow shape. Forming one end of a thick and large outer diameter pipe material into a thick onion shape by energizing upset, and forming one end formed into a thick onion shape into an umbrella shape by hot forging The purpose is to include a process.

  According to the configuration of the above invention, one end portion of the pipe material is formed into a thick onion shape by energizing upset molding. Here, since the pipe material is thick and has a large outer diameter, the radial deformation with respect to the axial deformation of the pipe material is reduced during energization upset molding. Thereafter, one end portion formed into a thick onion shape in the previous step is formed into an umbrella shape by hot forging, and a rough shape of the umbrella portion is obtained.

  According to the first aspect of the present invention, wrinkles due to buckling can be prevented from occurring in a thick onion-shaped portion by energizing upset molding, and subsequent molding failure of the umbrella portion can be prevented.

  According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, it is possible to use a heat-resistant material for the pipe material, thereby improving the heat resistance of the hollow valve.

  According to the invention described in claim 3, in addition to the effect of the invention described in claim 2, the umbrella shape can be shaped into an arbitrary shape.

  According to the invention described in claim 4, in addition to the effect of the invention described in claim 3, the cooling effect can be obtained by the sealed hollow, and the material characteristics of the umbrella part and the shaft end part can be changed.

  According to invention of Claim 5, durability of a hollow valve can be improved.

  According to the sixth aspect of the present invention, wrinkles due to buckling can be prevented from occurring in a thick onion-shaped portion by energizing upset molding, and subsequent molding failure of the umbrella portion can be prevented.

[First Embodiment]
Hereinafter, a first embodiment embodying a method for manufacturing a hollow valve according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a front view of a hollow valve 1 of this embodiment. This hollow valve 1 is used as an intake valve or an exhaust valve of an engine. The hollow valve 1 includes a shaft portion 2, an umbrella portion 3 formed at one end portion (base end portion) of the shaft portion 2, a groove portion 4 and a shaft provided at the other end portion (tip end portion) of the shaft portion 2. And an end portion 5. The end portion of the umbrella portion 3 is constituted by an umbrella end member 6, and the tip portion of the shaft portion 2 is constituted by a shaft end member 7. The umbrella end member 6 and the shaft end member 7 are made of a material different from that of the shaft portion 2.

  Next, the manufacturing method of this hollow valve 1 is demonstrated. FIG. 2 is a flowchart showing this manufacturing method. 3 to 9 are sectional views showing each step of this manufacturing method. Below, it demonstrates sequentially according to each number attached | subjected to the flowchart of FIG.

  (1) In the first step, “preparation of pipe material” is performed. That is, as shown in FIG. 3, a pipe material 11 in which a core material 12 is inserted into a hollow 11a is prepared as a workpiece. In this work, a long pipe is cut into a predetermined length (for example, “150 to 300 mm”) to form a pipe material 11, and the core material 12 is inserted into the hollow 11 a by a predetermined length from one end of the pipe material 11. Can be obtained. In this embodiment, the core material 12 is inserted into the hollow 11 a by a length from the upper end portion of the pipe material 11 to the vicinity of the center of the pipe material 11. The pipe material 11 and the core material 12 preferably have the same high-temperature strength. In this embodiment, “SUS316” is used as the material.

  (2) In the second step, “energized upset molding” is performed. Here, the “energized upset molding” is a method in which a large current is passed through a molding portion, heated by resistance heat generated therein, and pressure is applied to place the molding portion. In order to perform this forming, as shown in FIG. 4, the pipe material 11 with the core material 12 inserted is erected on the shortening base 21, and the upper end of the pipe material 11, that is, the core material 12 of the pipe material 11 is inserted. The side that is being held is held by the anvil 22. A convex portion 21 a is provided on the upper side of the shortening base 21. The lower end portion of the pipe material 11 is inserted into the convex portion 21a and positioned. Further, the pipe material 11 is sandwiched and held by the clamp electrode 23 in the vicinity of the lower side of the anvil 22. The interval G1 between the anvil 22 and the clamp electrode 23 is determined in accordance with the size of the solid onion 13 described later. Then, the pipe material 11 is held between the shortening base 21 and the anvil 22. As shown in FIG. 4, this “energized upset molding” is performed at a predetermined value (for example, “1 to 2 kA”) between the anvil 22 and the clamp electrode 23 by a voltage of a predetermined value (for example, “2 to 4 V”). ), The pipe material 11 is compressed in the axial direction with a force of a predetermined value (for example, “0.5 to 2.0 kN”) by the shortening base 21. By energization by the clamp electrode 23, the upper end portion of the pipe material 11 is heated to several hundreds of degrees Celsius. Thereby, a solid onion 13 having a thick onion shape including the core material 12 is formed at the upper end portion of the pipe material 11. Hereinafter, the side on which the solid onion 13 of the pipe material 11 is molded is referred to as a proximal end portion of the pipe material 11, and the opposite side is referred to as a distal end portion of the pipe material 11.

  (3) In the third step, “hot forging” is performed. That is, by forging the pipe material 11 formed with the solid onion 13 in the second step while being heated at a predetermined temperature between the forging upper die 24 and the forging lower die 25 as shown in FIG. The solid onion 13 is molded into an umbrella shape. At this stage, the shaft portion 2 of the hollow bulb 11 and the primary umbrella-shaped portion 14 having an approximate shape (rough shape) of the umbrella portion 3 are obtained. Here, the heating temperature at the time of forging is a temperature around “900 ° C. to 1200 ° C.”. This temperature is lower than the melting points of the pipe material 11 and the core material 12 and higher than the transformation point.

  (4) In the fourth step, “cutting” is performed. That is, the primary umbrella-shaped portion 14 formed into a rough shape in the third step is shaped by cutting to be processed into a secondary umbrella-shaped portion 15 having a horn shape as shown in FIG. At this time, the core material 12 is removed from the pipe material 11, and the pipe material 11 is in a hollow state in which both ends are opened.

  (5) In the fifth step, “part assembly” is performed. That is, as shown in FIG. 7, by fitting the umbrella end member 6 into the end opening 15a of the secondary umbrella-shaped part 15 processed into a horn shape, the end opening 15a is closed and the umbrella part 3 is Constitute. Further, the shaft end member 7 is fitted into the tip end opening 11b of the pipe material 11 opposite to the umbrella portion 3, and the tip opening 11b is sealed. In this embodiment, the umbrella end member 6 is formed in a special shape that constitutes the bottom of the umbrella part 3 using “SUH35” as a material. The shaft end member 7 constitutes a part of the shaft portion 2, has the same outer diameter as the outer diameter of the shaft portion 2, and is formed in a rod shape using “SUH1” as a material. A small diameter portion 7 a is formed at one end of the shaft end member 7. The small diameter portion 7a is formed to have substantially the same size as the inner diameter of the tip opening 11b of the pipe material 11.

  (6) In the sixth step, “part welding” is performed. That is, as shown in FIG. 8, the joint between the umbrella end member 6 and the secondary umbrella-shaped portion 15 is joined by welding W1, and the joint between the small diameter portion 7a of the shaft end member 7 and the tip opening 11b is welded. Join by W2. Thereby, the crude product of the hollow valve 1 is obtained. The hollow 11a of the crude product is filled with air as a refrigerant.

  (7) In the seventh step, “finishing” is performed. That is, by cutting and grinding the crude product shown in FIG. 8, as shown in FIG. 9, the final shape of the hollow valve 1 is obtained, and the dimensional accuracy and surface roughness are finished. At this time, the groove portion 4 and the shaft end portion 5 are formed in the shaft end member 7. In this way, the hollow valve 1 shown in FIG. 1 is obtained.

  According to the manufacturing method of the hollow valve 1 of this embodiment described above, in the second step, one end portion of the pipe material 11 in which the core material 12 is inserted is energized upset, so that the one end portion is thick. A meat solid onion 13 is formed. Here, since the core material 12 is inserted into one end portion of the pipe material 11, the thickness of the pipe material 11 is substantially increased by the amount of the core material 12. Therefore, when the pipe material 11 is compressed in the axial direction by energizing upset molding, the radial deformation relative to the axial deformation of the pipe material 11 is reduced. For this reason, it is possible to prevent wrinkles due to buckling from occurring on the outer periphery of the solid onion 13 during energization upset molding. This means that when a solid onion 13 is hot forged to form the primary umbrella-shaped portion 14 in the third step, which is a subsequent step, a forging defect such as a fold-in defect is generated in the inside. This can be prevented, and finally, molding defects of the umbrella part 3 can be prevented. In this sense, the durability of the hollow valve 1 can be improved.

  In this embodiment, by performing hot forging in the third step, the thick solid onion 13 portion heated in the second step, which is the previous step, becomes a thick umbrella by hot forging. It is formed into a primary umbrella-shaped portion 14 having a shape. Since hot forging is performed in this way, a durable heat resistant material can be used for the pipe material 11. Thereby, the heat resistance of the hollow valve 1 can be improved.

  In this embodiment, by performing cutting in the fourth step, the primary umbrella-shaped portion 14 formed into a thick umbrella shape in the third step, which is the previous step, is formed into a predetermined shape by cutting. It is formed in the next umbrella-shaped part 15. Since cutting is performed in this manner, the primary umbrella-shaped portion 14 can be shaped into a secondary umbrella-shaped portion 15 having an arbitrary shape. Moreover, the core material 12 is removed from the pipe material 11 by cutting, and the pipe material 11 having the secondary umbrella-shaped portion 15 can be made into a hollow state in which both ends are opened.

  In this embodiment, component assembly and component welding are performed in the fifth and sixth steps. Here, in the previous fourth step, an end opening 15a and a tip opening 11b are formed at both ends of the pipe material 11, respectively. And since the end opening 15a of the secondary umbrella-shaped part 15 is obstruct | occluded by the umbrella end member 6, and the front-end | tip opening 11b of the pipe raw material 11 is obstruct | occluded by the shaft end member 7, it finally becomes hollow as shown in FIG. A hollow valve 1 in which 11a is sealed is obtained. For this reason, a cooling effect can be obtained for the hollow valve 1 by the sealed hollow 11a. Further, it is possible to select a durable material harder than the pipe material 11 for the umbrella end member 6 and the shaft end member 7. For this reason, the material characteristic of the umbrella part 3 and the shaft end part 5 can be changed. Specifically, the durability of the umbrella portion 3 can be improved by the highly durable umbrella end member 6. Further, the durability of the shaft end portion 5 can be improved by the highly durable shaft end member 7. That is, durability can be improved by making the umbrella part 3 and the shaft end part 5 harder than other parts. In particular, with respect to the shaft end portion 5, high wear resistance can be ensured for the tip surface that frequently comes into contact with a rocker arm, a valve lifter or the like.

[Second Embodiment]
Next, a second embodiment that embodies the method for manufacturing a hollow valve according to the present invention will be described in detail with reference to the drawings. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. Hereinafter, different points will be mainly described.

  In this embodiment, the configuration of the hollow valve manufacturing method is different from that of the first embodiment in the first to third steps. Below, it demonstrates sequentially according to the flowchart of FIG.

  (1) In the first step, “preparation of pipe material” is performed. That is, as shown in FIG. 10, a pipe material 31 having a thick wall, a large outer diameter, and a hollow 31a is prepared. This is obtained by cutting a long pipe into a predetermined length (for example, “150 to 300 mm”). In this embodiment, the outer diameter D1 of the pipe material 31 is “10 mm”, and the outer diameter of the pipe material that has been conventionally used is “6 mm”, which is “1.5 times” or larger. Have Further, in this embodiment, the thickness T1 of the pipe material 31 is “3 mm”, and the thickness of the pipe material conventionally used is “1.2 mm”, while being “2.5 times”. ”. Also in this embodiment, “SUS316” is used as the material of the pipe material 31.

  (2) In the second step, “energized upset molding” is performed. Also in this embodiment, the same material as in the first embodiment is used, and the pipe material 31 is molded under the same conditions. Thereby, as shown in FIG. 11, a hollow onion 32 having a thick onion shape is formed at the upper end portion of the pipe material 31.

  (3) In the third step, “hot forging” is performed. That is, the pipe material 31 in which the hollow onion 32 is formed in the second step is forged while being heated at a predetermined temperature using an apparatus similar to that of the first embodiment, so that the hollow onion 32 is formed in FIG. Mold into an umbrella shape as shown. At this stage, a primary umbrella-shaped portion 33 having an approximate shape (rough shape) of the umbrella portion 3 of the hollow valve 1 is obtained. Next, the portion of the pipe material 31 that becomes the shaft portion 2 of the hollow valve 1 is subjected to “shaft ironing” by cold forging. As a result, as shown in FIG. 13, the portion other than the primary umbrella-shaped portion 33 of the pipe material 31 is thinned, and the inner diameter of the portion that becomes the shaft portion 2 is determined.

  Thereafter, the fourth to seventh steps are performed in the same manner as in the first embodiment, whereby the same hollow valve 1 as shown in FIGS. 1 and 9 is obtained.

  Therefore, in this embodiment, one end portion of the pipe material 31 is formed into a hollow onion 32 having a thick onion shape by energizing upset molding. Here, since the pipe material 31 is thick and has a large outer diameter, the radial deformation relative to the axial deformation of the pipe material 31 is reduced during energization upset molding. For this reason, it is possible to prevent wrinkles due to buckling on the outer periphery of the hollow onion 32 during energization upset molding. This prevents a forging defect such as a fold-in defect from occurring when the hollow onion 32 is hot forged to form the primary umbrella-shaped portion 33 in the third step, which is a subsequent step. Finally, it is possible to prevent molding defects of the umbrella part 3. Other functions and effects of this embodiment are basically the same as those of the first embodiment.

  In addition, this invention is not limited to the said embodiment, A part of structure can be changed suitably in the range which does not deviate from the meaning of invention, and it can also implement as follows.

  (1) In the first embodiment, the member assembled to the tip opening 11 b of the pipe material 11 is the relatively long shaft end member 7, but this member 7 includes only the groove portion 4 and the shaft end portion 5. It may be a short shaft end member.

  (2) In the embodiment, air is filled in the hollow 11a of the hollow valve 1 as a refrigerant. However, a sodium-based refrigerant may be injected instead of air.

The front view which shows a hollow valve. The flowchart which shows the manufacturing method of a hollow valve. Sectional drawing which shows a pipe raw material in connection with a 1st process. Sectional drawing which shows an electric upset shaping | molding in connection with a 2nd process. Sectional drawing which shows a hot forging in connection with a 3rd process. Sectional drawing which shows the pipe raw material in connection with a 4th process after cutting. Sectional drawing which concerns on a 5th process and shows components assembly | attachment. Sectional drawing of the crude product which concerns on a 6th process and shows component welding. Sectional drawing which shows the hollow valve after a finishing process in connection with a 7th process. Sectional drawing which shows a pipe raw material in connection with a 1st process. Sectional drawing which shows the pipe raw material in connection with a 2nd process and carrying out an electric upset shaping | molding. Sectional drawing which shows the pipe raw material in connection with a 3rd process after hot forging (after umbrella formation shape). Sectional drawing which shows the pipe raw material after a hot forging (after axial ironing) in connection with a 3rd process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hollow valve 2 Shaft part 3 Umbrella part 4 Groove part 5 Shaft end part 6 Umbrella end member 7 Shaft end member 11 Pipe material 11a Hollow 12 Core material 13 Solid onion 14 Primary umbrella-shaped part 15 Secondary umbrella-shaped part 31 Pipe material 31a Hollow 32 Hollow Onion 33 Primary umbrella-shaped part

Claims (6)

A manufacturing method of a hollow valve comprising a shaft portion and an umbrella portion formed at one end of the shaft portion, and forming a hollow shape,
A core material is inserted into the pipe material by a predetermined length from one end of the pipe material, and one end of the pipe material into which the core material is inserted is formed into a thick onion shape by energizing upset molding. A method for producing a hollow valve, comprising a step. The method for manufacturing a hollow valve according to claim 1, further comprising a step of forming the one end portion formed into the thick onion shape into an umbrella shape by hot forging. The method for manufacturing a hollow valve according to claim 2, further comprising a step of cutting the one end portion formed into the umbrella shape into a predetermined shape. The hollow valve according to claim 3, further comprising a step of assembling an umbrella end member at the one end portion cut into the predetermined shape and assembling a shaft end member at the other end of the pipe material. Production method. The hollow valve manufactured by the manufacturing method of the hollow valve of Claim 4. A manufacturing method of a hollow valve comprising a shaft portion and an umbrella portion formed at one end of the shaft portion, and forming a hollow shape,
Forming one end of a thick, large-diameter pipe material into a thick onion by energizing upset;
A method of manufacturing a hollow valve, comprising: a step of forming the one end portion formed into the thick onion shape into an umbrella shape by hot forging.

Images