JP2005161402A - Hydroforming die and hydroforming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydroforming die and a hydroforming method, wherein a cutting stage and a finishing stage after hydroforming are eliminated and the productivity is improved. <P>SOLUTION: The hydroforming die 1 (a die main body 4 consisting of a lower die 2 and an upper die 3) is constituted so that partitions 10 (parting walls 8, 9) for dividing a cavity 5 into a plurality of cavities are formed and fluid becomes movable in the plurality of cavities 5a, 5b divided with the partitions 10 by providing distribution holes 11 on this partition 10. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a hydroform molding die and a hydroform molding method used to perform molding (hydroform molding) using fluid pressure.

  In hydroform molding, a manufacturing method may be employed in which a plurality of identical or different parts are integrally molded and cut after molding to obtain a plurality of finished products (molded products). For example, JP-A-8-323430 (Patent Document 1) describes a method of obtaining two finished products by cutting a molded product in half after bulge processing. When this method is used, a plurality of parts can be formed by a single hydroform molding, so that productivity can be improved.

  FIG. 15 shows a conventional hydroforming mold 30. As shown in FIG. 15, the hydroforming mold 30 is inserted into a mold body 33 including a lower mold 31 and an upper mold 32 and a cavity 34 in the mold body 33 from both the left and right sides. The shaft pressing punches 35 and 36 are configured. The cavity 34 in the mold main body 33 includes a pair of left and right inner surface portions α corresponding to the outer peripheral dimensions of the material pipe to be molded, and two locations adjacent to the inner surface portions α (proximal portions at both ends of the material pipe). And a bulge portion β formed at two locations) and an inner surface portion γ formed between these bulge portions β and having an inner diameter larger than the inner diameter of the inner surface portion α. ing. Further, one shaft pressing punch 35 is provided with a fluid supply hole 37.

Thus, when performing hydroformed cleaves material pipe to be of hydroformed into a predetermined length (see step S ₁ in FIG. 16), chamfering the end portions of the material pipe (in FIG. 16 reference should be made to step S _2). Then, such a material pipe and to prepare to hydroformed (see step S ₃ in Fig. 16). In the hydroforming, the steps shown in FIGS. 17A to 17F are sequentially performed. Specifically, one material pipe 40 as shown in FIG. 17A is prepared, this material pipe 40 is attached to the lower mold 31, and the upper mold 32 is closed (shown in FIG. 17B). (Clamp it like Next, as shown in FIG. 17C, the pair of shaft pressing punches 35 and 36 are pressed against both ends of the material pipe 40 from the left and right sides in the axial direction to close the openings at both ends of the material pipe 40. Then, the fluid (for example, liquid such as water or emulsion) 41 is filled into the material pipe 40 through the fluid supply hole 37 of the one axial push punch 35. Thereafter, as shown in FIG. 17 (d), the pressure of the fluid inside the material pipe 40 is increased by a pressure intensifier outside the figure while pushing the pair of axial push punches 35 and 36, so that the material pipe 40 is It is formed into a shape corresponding to the shape of the cavity 34 (for example, a circular shape having bulging portions 42 and 43 at both end portions). Then, the material pipe 40 molded in this way is taken out from the mold 30 (see FIG. 17E), and the center part in the longitudinal direction is cut to obtain two molded products 40a and 40b (step of FIG. 16). S ₄ and FIG. 17 (f) refer). Then, the molded product 40a, 40b and cutting a, while ensuring the overall length and parallelism, and molded product by performing a chamfering of the end face (see step S ₅ of FIG. 16).
JP-A-8-323430

  However, since the conventional hydroform molding requires cutting and finishing processes after molding, the large number of processes causes the limit of productivity improvement and the cost increase. In addition, since it is necessary to chuck the component after hydroforming, problems such as scratches on the surface of the component and distortion of the shape are likely to occur. If only one part is formed, the cutting process can be omitted, but only one part can be formed with a pair of axial push punches. There is a problem of being inferior.

  The present invention has been made in view of the above-described problems, and its purpose is to eliminate the cutting step and finishing step after hydroforming, and to improve productivity. The object is to provide a mold for forming a foam and a method for forming a hydroform.

In order to achieve the above object, in the present invention, in the hydroforming mold, the mold includes a partition that divides the cavity into a plurality of partitions, and the partition is partitioned by the partition by providing a flow hole. The fluid is configured to be movable in the plurality of cavities.
The present invention is also directed to a hydroforming mold, wherein the mold includes a plurality of cavities, and a flow hole is provided in a partition wall between the plurality of cavities adjacent to each other, thereby allowing fluid to flow in the plurality of cavities. It is configured to be movable.
In the present invention, an axial push punch that advances in the cavity toward the partition is provided.
In the present invention, the axial push punch is disposed at each end of the mold opposite to the partition in the plurality of cavities, and the fluid can move through a flow hole provided in the partition. Thus, the axial push punches are configured to advance in a direction approaching each other.
In the present invention, the cavity includes a plurality of surfaces whose inner diameter changes intermittently or continuously, and a surface having the smallest inner diameter among the plurality of surfaces is adjacent to the partition wall.
Further, in the present invention, the wall surface of the partition wall that abuts the end surface of the pipe material, which is a member to be molded, is constituted by a plate separate from the mold body composed of the lower mold and the upper mold, and the plate can be attached and detached. It is said.
Further, in the present invention, the plate is elastically moved in a direction in contact with the end surface of the tube material against the compressive force applied to the tube material from the axial push punch, and the plate is moved to the end surface of the tube material. The partition wall is provided with a seal mechanism that functions to always contact.
Further, in the present invention, the sealing mechanism is constituted by a main body portion of the partition wall, the separate plate, and an elastic member interposed between the main body portion of the partition wall and the separate plate, The separate plate is movable by the elasticity of the elastic member.
Moreover, in this invention, the inclined surface which inclines to the outer peripheral side of the said cavity as the said flow hole is approached is provided in the circumference | surroundings location of the said flow hole on the surface of the said partition.
In the present invention, a separate pipe expansion piece that does not move with the mold during the opening and closing operation of the mold is provided, and the inclined surface is provided on the pipe expansion piece.
In the present invention, the plurality of cavities are formed in a symmetrical shape with the partition wall as the center of symmetry.
Further, in the present invention, in the hydroform molding method for simultaneously molding a plurality of pipe materials, the pipe materials are arranged in each of the plurality of cavities partitioned by the partition walls in the mold, the inside of the pipe material is filled with a fluid, and the fluid Is configured to simultaneously form a plurality of pipes in the plurality of cavities by applying pressure to the fluid under a condition in which the fluid can be moved between the insides of the plurality of pipes through a flow hole provided in the partition wall. ing.
In the present invention, the axial push punch disposed at the end of the mold opposite to the partition in the cavity is advanced toward the partition while applying pressure to the fluid.
In the present invention, the end face of the pipe material is preliminarily chamfered and then placed in the cavity.
Moreover, in this invention, the area | region which does not produce the said pipe expansion is arrange | positioned adjacent to the said partition among the area | region which produces a pipe expansion at the time of shaping | molding of the said pipe material, and the area | region which does not produce a pipe expansion.
Further, in the present invention, when the inner diameter of the inner surface of the cavity changes intermittently or continuously, the end surface of the tube material having an outer diameter substantially the same as the inner diameter of the cavity inner surface adjacent to the partition wall is brought into contact with the partition wall. It arranges in the state where it was made to.

  In the first aspect of the present invention, the hydroforming mold includes a partition wall that divides the cavity into a plurality of cavities, and a fluid is movable in the plurality of cavities partitioned by the partition wall by providing a flow hole in the partition wall. Since it is configured, a plurality of parts can be simultaneously molded by a common molding process. In addition, since the molded product obtained using the hydroform mold according to the present invention does not require cutting or finishing after molding, it is easy to manage the dimensions of the molded parts and the number of manufacturing steps. Reduction is possible, and productivity can be improved. In addition, since fluid can move through the flow holes, pressure is evenly applied to the inner surface of the pipe during molding, and multiple pipes can be pressurized simultaneously by simply pressurizing the fluid in multiple cavities from one side. It becomes possible to mold.

The present invention according to claim 2 is provided with a plurality of cavities in a hydroforming mold, and a flow hole is provided in a partition wall between a plurality of adjacent cavities so that fluid can move in the plurality of cavities. Since it is configured, a plurality of parts can be simultaneously molded by a common molding process. In addition, since the molded product obtained using the hydroform mold according to the present invention does not require cutting or finishing after molding, it is easy to manage the dimensions of the molded parts and the number of manufacturing steps. Reduction is possible. In addition, since fluid can move through the flow holes, pressure is evenly applied to the inner surface of the pipe during molding, and multiple pipes can be pressurized simultaneously by simply pressurizing the fluid in multiple cavities from one side. It becomes possible to mold.

  According to the third aspect of the present invention, since the axial push punch that advances in the cavity toward the partition wall is provided, a force is applied in the direction in which the end portion of the pipe material is pressed against the partition wall. The fluid is sealed well at the end of the tube material, and molding defects can be prevented.

  In the present invention according to claim 4, the axial push punch is disposed at each end of the mold opposite to the partition walls in the plurality of cavities, and the fluid can move through the flow holes provided in the partition walls. Since the axial push punches are configured to move forward in the direction approaching each other, the pressure applied to the fluid by the pressure intensifier can be evenly transmitted to the plurality of cavities partitioned by the partition walls. In addition, since force is applied to the partition from both sides, the burden due to excessive weight on the partition is reduced, and damage to the mold can be prevented.

  According to a fifth aspect of the present invention, the cavity includes a plurality of surfaces whose inner diameter changes intermittently or continuously, and a surface having the smallest inner diameter among the plurality of surfaces is adjacent to the partition wall. Thus, the following effects can be obtained. That is, when selecting a pipe material having an outer diameter equal to or less than the minimum diameter of a mold (molding die) and molding the pipe material, by adopting the structure as described above, pipe expansion on the partition wall side can be suppressed. It is possible to satisfactorily seal the fluid at the end of the tube material and prevent molding defects.

  Further, in the present invention according to claim 6, the wall surface of the partition wall that comes into contact with the end surface of the pipe material that is a molding target member is constituted by a plate separate from the mold body composed of the lower mold and the upper mold, Since this plate is removable, if the wall surface is damaged or worn out due to repeated molding, the mold is repaired (especially polishing the wall surface of the partition wall) or replaced. It is possible to prevent occurrence of pressure leakage during molding and transfer of scratches to the end face of the molded product by simply exchanging only the plate.

  According to the seventh aspect of the present invention, the plate is elastically moved in a direction in which the plate abuts against the end face of the pipe material against the compressive force applied to the pipe material from the axial push punch, and the plate is moved to the end face of the pipe material. Since the partition wall is provided with a seal mechanism that functions to always contact, the presence of this seal mechanism allows the plate as the wall surface to always follow the end surface of the tube material. Thus, it is possible to prevent pressure leakage due to shrinkage in the axial direction of the tube material being formed.

In the present invention according to claim 8, the sealing mechanism includes a main body portion of the partition wall, a separate plate, and an elastic member interposed between the main body portion of the partition wall and the separate plate. Since the separate plate can be moved by the elasticity of the elastic member, it is possible to prevent pressure leakage only by providing a sealing mechanism having a simple structure.

  The present invention according to claim 9 is such that an inclined surface that is inclined toward the outer peripheral side of the cavity as it comes closer to the flow hole is provided at a location around the flow hole on the surface of the partition wall. Even in the case of performing the above, it is possible to satisfactorily seal the fluid at the end of the tube material, and to prevent molding defects.

  Since the present invention according to claim 10 is provided with a separate pipe expansion piece that does not move with the mold during the opening and closing operation of the mold, and an inclined surface is provided on the pipe expansion piece, The top is not moved together with the mold (for example, the lower mold or the upper mold) during the opening / closing operation of the mold, so that the inclined surface of the top is the end of the pipe (the inner peripheral edge of the end opening of the pipe) ) And the degree of freedom of the inclined surface can be improved.

  In the present invention according to claim 11, since the plurality of cavities are formed in a bilaterally symmetric shape with the partition wall as the symmetric center, it becomes possible to apply pressure by the fluid evenly to the pipe material, Defects can be prevented.

  According to a twelfth aspect of the present invention, in the hydroform molding method for simultaneously molding a plurality of pipe materials, the pipe materials are arranged in each of the plurality of cavities partitioned by the partition walls in the mold, and the inside of the pipe material is filled with a fluid. , Under the condition that the fluid can move between the inside of the plurality of pipes through the flow hole provided in the partition wall, by applying pressure to the fluid, a plurality of pipes in the plurality of cavities are simultaneously molded Therefore, a plurality of parts can be simultaneously molded by a common molding process. Compared to the method of cutting the molded product after molding and dividing it into multiple parts, the molded product does not need to be cut or finished after molding, so it is easier to manage the dimensions of the molded product and reduce the number of processes. It becomes possible, and productivity can be improved. Further, since the fluid flows through the flow holes at the time of molding and pressure is evenly applied to the pipe material to be molded, pressure can be simultaneously applied to the fluid in the plurality of cavities by one pressurizing operation.

  The present invention according to claim 13 is configured such that the axial push punch disposed at the end of the mold opposite to the partition in the cavity is advanced toward the partition while applying pressure to the fluid. Therefore, a force is applied in the direction in which the end portion of the tube material is pressed against the partition wall, so that the fluid is well sealed at the end portion of the tube material, and molding defects can be prevented.

  The present invention according to claim 14 is a method in which the end face of the pipe material is preliminarily chamfered and then placed in the cavity. As compared with the above, it is possible to omit the step of impairing the dimensional accuracy after molding the part. This will be described in more detail as follows. In other words, the accuracy of the parts (roundness, etc.) is high before forming, that is, in the tube material state, and chamfering can be performed with high accuracy if chamfering is performed in this state. In general, the accuracy of parts decreases due to the influence of the accuracy and the clearance with the mold. In this way, if chamfering is performed in a state where the accuracy is lowered, the processing accuracy is inevitably lowered. Also, when considering chucking to chamfer parts, the tube material is easy to chuck and chamfering accuracy is good, but after molding, the shape of the parts is complicated, so it can be chucked with high accuracy. The actual situation is difficult. In consideration of such actual conditions, if the pipe material is chamfered in advance before molding, the chamfering process can be performed easily and accurately, and the process that impairs the accuracy of the parts after molding is omitted. be able to.

  Since the present invention according to claim 15 is arranged such that a region where pipe expansion is not caused among the region where pipe expansion occurs at the time of forming the pipe material and the region where pipe expansion does not occur are arranged adjacent to the partition wall. It is possible to satisfactorily seal the fluid at the end of the tube material and prevent molding defects.

  According to the sixteenth aspect of the present invention, when the inner diameter of the inner surface of the cavity changes intermittently or continuously, the end face of the pipe material having an outer diameter substantially the same as the inner diameter of the inner surface of the cavity adjacent to the partition wall is applied to the partition wall. Since they are arranged in contact with each other, it is possible to suppress the expansion of the pipe on the partition wall side, and it is possible to satisfactorily seal the fluid at the end of the pipe.

  Hereinafter, a hydroform molding die and a hydroform molding method according to an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 shows a hydroforming mold 1 according to a first embodiment of the present invention. As shown in FIG. 1, the hydroforming mold 1 is inserted into a mold body 4 including a lower mold 2 and an upper mold 3 and a cavity 5 in the mold body 4 from both the left and right sides. It consists of axial push punches 6 and 7. The above-described lower mold 2 and upper mold 3 are formed with partition walls 8 and 9 including projecting portions at the left and right central portions, and when the lower mold 2 and the upper mold 3 are clamped. The partition walls 8 and 9 are arranged in correspondence with each other to form one partition wall (partition wall that partitions the cavity 5 into two cavities 5a and 5b) 10 and, for example, a circular through hole in the central portion of the partition wall 10 A flow hole 11 composed of holes is formed. Thus, at the time of molding, a fluid (a liquid 15 to be described later) can move between the cavities 5 a and 5 b adjacent to each other across the partition wall 10 through the above-described flow hole 11.

Further, when the lower mold 2 and the upper mold 3 are clamped, the cavity 5 formed inside the mold body 4 is configured to have a bilaterally symmetric shape with the partition wall 10 as the center of symmetry. The left and right side portions of the cavity 5 (the cavities 5a and 5b adjacent to each other) are configured to correspond to the shapes of the two material pipes to be formed. In the cavity 5 according to the present embodiment, the outer diameter D ₁ (see FIGS. 1 and 4) of the two pipe materials (for example, material pipes) to be molded is located at the left and right sides of the partition wall 10. A cylindrical surface A having an inner diameter is provided, and a cylindrical surface B having an inner diameter D ₂ slightly larger than the outer diameter D ₁ (that is, D ₁ <D ₂ ) at a location outside the mold surface from the cylindrical surface A. And a bulging surface (expanded molding surface) C is provided between these cylindrical surfaces A and B and in the vicinity of the partition wall 10. Thus, the cylindrical surface A having the smallest inner diameter is adjacent to the partition wall 10 among the plurality of surfaces A, B, and C (a plurality of surfaces whose inner diameter changes intermittently or continuously).

  Further, one axial push punch 6 of the pair of axial push punches 6 and 7 is provided with a fluid supply hole (through hole) 12 extending along the axial direction. The other axial push punch 7 is not provided with the fluid supply hole as described above.

It is as follows when the procedure at the time of shape | molding using the metal mold | die 1 for hydroform shaping | molding of such a structure is described referring FIG.2 and FIG.3.
(1) First, by cutting the pipe member that is elongated in the required dimensions, (a kind of tube) two material pipes as a molded object parts 13 and 14 is prepared (Fig. And Step M ₁ in FIG. 2 3 ( a)).
(2) Then, chamfering the end portions of the respective material pipes 13 and 14 (see step M ₂ in FIG. 2).
(3) Then, the material pipe 13 and 14 to hydroformed (see Step M ₃ and the diagram of FIG 2 3 (b) ~ (d)).
(4) In hydroforming, first, the material pipes 13 and 14 that have been chamfered in advance are set in the mold body 4 and the mold body 4 is clamped (see FIG. 3B). At this time, one end of each of the material pipes 13 and 14 is disposed corresponding to the partition wall 10 of the mold body 4 as shown in FIG. That is, among the region where pipe expansion is not performed when the material pipes 13 and 14 are formed and the region where pipe expansion is not generated, a region where pipe expansion is not generated is disposed adjacent to the partition wall 10.
(5) Next, the pair of left and right shaft pressing punches 6 and 7 are moved in a direction approaching each other along the axis of the mold body 4 and press-fitted into the other end portions of the material pipes 13 and 14 (FIG. 3C )reference). Along with this, one end portions of the pair of left and right material pipes 13 and 14 are crimped to the partition wall 10, and the other end portions thereof are expanded by the axial push punches 6 and 7 to close the openings.
(6) Under such a state, while filling the material pipes 13 and 14 with the fluid 15 (for example, water) through the fluid supply holes 12 of the axial push punch 6, the pair of left and right axial push punches 6 and 7 are Further advance in the direction approaching each other (that is, the direction of sandwiching the material pipe). At this time, the fluid 15 filled in the material pipes 13 and 14 can be moved between the adjacent cavities 5a and 5b on the left and right sides through the flow holes 11 of the partition wall 10, and is increased by a pressure booster (not shown). Pressure is applied to the fluid 15.
(7) Thereafter, the material pipes 13 and 14 are axially pushed by the axial push punches 6 and 7 to a predetermined position while increasing the internal pressure to complete the molding (see FIG. 3D).
(8) Thereafter, the finished molded parts 13 ′ and 14 ′ each having the bulging portions 16 and 17 at one end are taken out from the mold body 4 (see FIG. 3E).

By the above-described procedure, a molded part equivalent to the conventional two-part and three-step process (that is, hydroform molding step S ₃ → cutting step S ₄ → both end cutting (finishing) step S ₅ ) is This can be achieved by only one step of foam molding, and as a result, _two molded products can be obtained in a total of three steps M ₁ , M ₂ and M ₃ .

  By the way, in the case of the above-mentioned conventional two-piece / three-step process, dedicated equipment and a chuck mold are required for cutting and finishing at both ends, and the dimensional accuracy of the molded part is affected by variations and the like. In reality, it is difficult to ensure the accuracy of parts such as chamfering of the end. On the other hand, in the case of this embodiment, the chamfering of the end of the material pipe, which is performed even in the case of two chamfering and three processes, is slightly increased, so that the component accuracy (dimensional accuracy) such as chamfering of the component after molding. ) Can be secured. The material pipes 13 and 14 have a substantially circular cross section, and can easily improve the processing accuracy compared to the molded product.

  According to this embodiment, since cutting and both-end finishing are not performed after molding, equipment and a chuck die for that purpose are unnecessary.

  The hydroform molding die 1 according to the first embodiment of the present invention and the hydroform molding method using the die 1 have been outlined above. The distribution that is a feature of the hydroform molding die 1 is described here. The shape of the hole 11 and the cavity 5 will be described in detail as follows.

First, as shown in FIG. 4, the inner diameter D ₃ of the flow hole 11 is set smaller than the inner diameter D ₄ of the material pipes 13 and 14 (D ₃ <D ₄ ), and the end faces of the material pipes 13 and 14 are formed during molding. It is desirable to select it so that it does not interfere with the flow hole 11 even if it is slightly deformed. Specific guideline, there is no problem in most cases smaller 3mm or more than the internal diameter D ₄ of the material pipe 13, less the amount of axial pressing is such as when a small deformation end face, or may be less of a difference . On the other hand, when the inner diameter D ₃ of the circulation hole 11 is too small, insufficient supply of fluid 15 through the flow hole 11, poor molding becomes easy connection. As a result, the inner diameter D ₃ of the flow hole 11 is best about 3 mm smaller than the inner diameter D ₄ of the material pipes 13 and 14. Therefore, as described above, D ₃ <D ₄ is an absolute condition, and D ₁ = D ₂ −3 (mm) is an optimum condition.

  Further, the length of the flow hole 11 is not particularly defined, but it is desirable that the length is as short as possible as long as the length does not hinder the molding in terms of strength. The reason is that when the flow hole 11 is long, the flow of fluid is hindered.

  On the other hand, the shape of the cavity 5 will be described. If there is a difference in moldability between the left and right portions of the cavity 5, it is likely to cause a molding failure. However, it is not necessary to have a symmetrical shape, and when a molded part having a different shape is to be molded, a shape corresponding to the shape of the molded part may be set.

Further, the cavity 5 is preferably formed so that the side on which the pipe expansion is not performed is the mold center side (that is, the partition wall 10 side). That is, it is desirable to perform molding while expanding the tube with the axial push punches 6 and 7 in the outer portion so that the side to be expanded is outside the mold body 4. When the pipe expansion is not performed on the mold center side, as shown in FIG. 5, the mold outer ends 13a and 14a of the material pipes 13 and 14 are axially pressed by the axial push punches 6 and 7 to form the material pipes 13 and 14, respectively. While molding is performed while sealing the end surfaces and the inner and outer surfaces (outer end surface seal position P ₁ ), the material pipes 13 and 14 are formed by the mold body 4 at the center side end portions 13 b and 14 b of the material pipes 13 and 14. Sealing is performed at the end surface and the outer surface (center side end surface seal position P ₂ ), and sufficient sealing is achieved on both the outer side and the center side of the mold.

  However, when the mold center side is expanded, there is no change in the sealing condition on the outside of the mold, but at the mold center side, one end of the material pipes 13 and 14 is expanded and the overall length is shortened. Sealing at the end face becomes ineffective, and at that time, a gap G as shown in FIG. 6 is generated between the end face and the outer face of the material pipes 13 and 14 and the inner face 5a constituting the cavity 5 (see FIG. 6). (See arrow W)), further tube expansion cannot be performed, resulting in a defective shape. Therefore, it is desirable to arrange the pipes so that the pipes are not expanded as much as possible on the mold center side.

According to the hydroform molding method using the hydroform molding die 1 having the above-described configuration, the material pipe cutting step M ₁ , the material pipe chamfering step M ₂ , and the hydroform molding step M ₃ are calculated as described above. Since the molded part can be processed in only three processes, the conventional case (material pipe cutting process S ₁ , material pipe chamfering process S ₂ , hydroform molding process S ₃ , cutting process S ₄ , and cutting process S Compared to ₅ (5 steps required), the number of processing steps can be reduced. That is, according to this embodiment, the cutting process and finishing process after hydroform molding can be omitted, and productivity can be improved.

  Further, the hydroforming mold 1 of the present embodiment has a part-shaped cavity 5a, 5b on the left and right sides, and serves as a partition wall provided with a flow hole 11 through which a molding fluid 15 passes. The structure is provided with a partition wall 10 (see FIGS. 1 and 5). Therefore, according to this hydroform molding die 1, with the provision of the partition wall (partition wall) 10 having the flow holes 11 at the position where the part is cut, in one hydroform molding operation, A plurality of molded parts can be obtained without cutting the molded product after molding. Furthermore, by providing the flow hole 11 in the partition wall 10, molding can be performed only by supplying fluid from only the fluid supply hole 12 of the axial push punch 6 on one side. In addition, since the conventional normal hydroforming mold has a structure in which fluid is supplied from one axial push punch, it is not necessary to modify equipment for the fluid supply structure.

  The first embodiment of the present invention has been described above, but the present invention is not limited to this embodiment, and various modifications and changes can be made based on the technical idea of the present invention.

  For example, in the above-described embodiment, it is desirable not to expand the ends of the material pipes 13 and 14 on the mold center side. However, depending on the part shape, it may be necessary to expand the tube on the center side. . In such a case, an inclined surface 20 is provided on the center side end surface in the mold (see FIG. 8), or a separate tube expansion piece 21 that does not move with the mold is used (see FIG. 9). It is possible. Even in this case, it is desirable that the pipe end portion on the side with a small tube expansion rate is on the mold center side, and the mold end portion on the side with a large tube expansion rate is on the mold outside.

When the inclined surface 20 is installed in the mold 4, the outer peripheral side of the cavity 5 (specifically, the side surface of the partition wall 10 corresponding to the periphery of the circulation hole 11 provided in the partition wall 10 becomes closer to the circulation hole 11. Specifically, an inclined portion 22 having an inclined surface 20 inclined on the cylindrical surface A side) is provided. As shown in FIG. 8, the inclined portion 22 has a diameter D ₆ at the tip of the inclined surface 20 smaller than the inner diameter D ₄ of the material pipes 13 and 14, and a diameter D _{7 at the} root portion is an inner diameter D of the cavity 5. _A truncated cone shape smaller than ₁ by the thickness of the material pipes 13 and 14 (thickness t). In the the inclined portion 22, the height H ₁ of the inclined surface 20, it is necessary to suppress to a minimum. On the other hand, if the height H ₁ of the inclined surface 20 is too low, the inclination angle becomes small and the material pipe cannot be expanded. On the other hand, when the height H ₁ of the inclined surface 20 is too high, the molded product is caught on the inclined surface 20 after the completion of molding and is difficult to open. For this reason, the appropriate height H ₁ of the inclined surface 20 is 2 mm or more and 5 mm or less.

On the other hand, when the pipe expansion piece 21 is used in the hydroform molding die 1, the inclined portion 24 having the inclined surface 23 has the diameter D _{6 of the} tip portion smaller than the inner diameter D _{4 of the} material pipes 13, 14. The base portion has a diameter D _{7 which} is smaller than the inner diameter D _{1 of the} cavity 5 by the plate thickness t of the material pipes 13 and 14 (see FIGS. 9 and 10). The height of the inclined portion 24 is not limited. This has an effect on the opening and closing of the lower mold 2 and the upper mold 3 because the pipe expansion piece 21 exists independently of the mold body 4 (it does not move together with the mold body 4 when the mold is opened and closed). It is because it does not give. In view of this, it is desirable to preferentially select the inclination angle of the inclined surface 23 which is a condition for smooth pipe expansion. If this inclination angle θ is 45 degrees or more, smooth tube expansion is possible. If the inclination angle is determined, the height of the inclined portion 24 corresponding to the inclination angle is automatically determined. Further, if the height H ₂ of the top portion 25 inserted into the material pipes 13 and 14 is 5 mm or more, there is no problem when the mold is set or when the pipe is expanded in the mold 1.

The diameter D ₆ of the tip of the inclined portion 24, the diameter D ₇ of the root portion of the inclined portion 24, the cavity inner diameter D ₁ (= material pipe inner diameter D ₁ ), the height H ₂ of the piece portion 25 (the height of the piece portion material pipe insertion) The relationship between the thickness t of the material pipes 13 and 14, the inner diameter D ₄ of the material pipes 13 and 14, and the inclination angle θ of the inclined surface is
(A) D ₆ <D ₄
(B) D ₇ = D ₁ -2 × t
(C) θ ≧ 45 °
(D) H ₂ ≧ 5 (mm)
It is.

  Further, the present invention is not limited to the material pipes 13 and 14 having a circular cross section, but can be applied to pipes having various cross sectional shapes such as a rectangular cross section and an elliptical cross section. Further, pipes for various uses other than the material pipe are formed. It can be an object.

  In the above-described embodiment, two cavities 5a and 5b are provided to obtain two molded parts by one hydroform molding operation. The present invention can also be applied to the case where three or more matching cavities are provided and three or more molded parts are simultaneously molded by one hydroform molding operation. Specifically, when a part with a small tube expansion rate is less likely to cause seal leakage during molding, or when a mechanism that can control the amount of movement is provided by making the partition wall movable, 3 It is possible to simultaneously mold more than one part.

  Here, it will be as follows if the Example of the metal mold | die for hydroform molding and hydroform molding method which concern on this invention is described.

Example 1
Molding was performed by the method shown in the present plan (Example 1) and the conventional method (Comparative Example). Each part was molded two at a time. And it shape | molded by the metal mold | die shape and a shaping | molding procedure as shown in FIG. The shape of the molded part is shown in FIG. The material pipe has an outer diameter D ₁ = 37.0 mm and a plate thickness t = 3.0 mm. Molded parts, the total length is at L = 52.0 mm, the maximum outer diameter D ₅ of the bulge portion (expanded portion) is 50.0 mm.
As a comparative example, similar molding was performed using a mold shape and molding procedure as shown in FIG. The outer diameter and plate thickness of the material pipe of the comparative example were the same as in the example, but the total length was 5 mm longer than twice the example in consideration of the cutting allowance and cutting allowance at the center.
There was no difference in formability and molding time between the examples and the comparative examples. In the comparative example, the processing time was longer by the amount of the subsequent process (cutting, cutting). It was found that the example had no problem in molding as in the comparative example, and the productivity was higher.

Example 2
Parts similar to those of Example 1 were formed at separate positions corresponding to the center side end face, and molded while expanding the center side end face. Therefore, a material pipe having an outer diameter of D ₁ = 35.0 mm and a plate thickness of t = 3.1 mm was used.
Molding was performed in the same manner as in Example 1, but almost the same parts could be molded without causing problems such as seal leakage.

  12 to 14 show a hydroforming mold 50 according to the second embodiment of the present invention. 12 to 14, the same parts as those in FIGS. 1 to 11 are denoted by the same reference numerals and redundant description is omitted.

  The hydroforming mold 50 according to the present embodiment is formed by integrally molding a plurality of identical or different parts at the same time, cutting a molded part into a finished product by omitting a finishing step after molding. This is a hydroforming mold that can be used to prevent pressure leaks during molding and to prevent defects due to wear and damage of the mold, thereby reducing molding defects caused by pressure leaks during molding. It is intended to prevent problems such as a decrease in dimensional accuracy.

  As shown in FIG. 12, the hydroform molding die 50 includes partition walls 8 and 9 provided between the left and right cavities 5a and 5b in the hydroform molding die 1 according to the first embodiment described above. (Ie, the partition wall 10) is replaced with a separate combination 51 from the mold body 4 composed of the lower mold 2 and the upper mold 3, and the separate combination 51 is replaced with a cavity. 5 is arranged as a partition wall (partition wall) for partitioning 5. As shown in FIGS. 12 and 13, the above-described combined body 51 includes one piece 52 constituting a main body portion of the partition wall, a pair of plates 53 and 53, and a pair of O-rings 54 and 54. The combined body 51 constitutes a partition wall for partitioning the cavity 5.

  More specifically, as shown in FIG. 12, one half of an annular piece 52 is fixed to the inner peripheral wall of the lower mold 2 in a fitted state, and the mold is clamped. Accordingly, the upper mold 3 is configured to be fitted into the other half portion of the top 52. An annular projecting piece portion of the inner diameter portion of the top 52 is provided as one wall portion 55 (partition wall main body portion of the cavity 5) that partitions the cavity 5. Is formed.

  Further, annular plates 53 and 53 each having a flow hole 57 at the center are respectively arranged on both the left and right sides of the wall portion 55, and between these plates 53 and 53 and the partition wall 55 described above. Are respectively provided with O-rings (elastic members) 54 and 54 having elasticity. As shown in FIGS. 12 and 13, the outer peripheral surface of each plate 53 is slidably disposed on the cylindrical surface A of the cavity 5 and the cylindrical surface A ′ of the inner periphery of the top 52 so as to be movable. 53 flow holes 57 are arranged corresponding to the flow holes 56, and a series of flow holes 58 through which a molding fluid (for example, water) passes are formed by these flow holes 56, 57. . The reason for providing such a flow hole 58 is that the fluid supplied from the axial push punch 6 on one side is the same as in the case of the hydroforming mold 1 according to the first embodiment described above. This is because it is possible to apply an internal pressure equally to the material pipes 13 and 14 installed in both the cavities 5a and 5b by allowing the cavities 5a and 5b to freely move back and forth.

  On the other hand, the above-described pair of plates 53 and 53 are movable members (movable members that are slidable along the axial direction of the cavity 5) separate from the lower mold 2 and the upper mold 3. It can be attached to and detached from the main body 4. Thus, since the pair of plates 53 and 53 are configured to be movable, the dimensional accuracy of the entire length of the molded part is affected. Therefore, at the final stage of molding, the pair of plates 53 and 53 are paired. The O-rings 54 and 54 are configured to abut (compress) both surfaces of the wall portion 55 which is the main body portion of the partition wall.

  Thus, the wall surface of the partition wall that comes into contact with the end face of the pipe material, which is a member to be molded, is constituted by a pair of detachable plates 53, 53 that are separate from the mold body 4 including the lower mold 2 and the upper mold 3. ing. And it intervened between the wall part 55 as a partition main-body part which consists of the protrusion piece part of the top | top | piece 52, a pair of separate plates 53 and 53, and the said wall part 55 and a pair of plates 53 and 53, respectively. A seal mechanism 60 composed of O-rings 54 and 54 is provided, and the pair of plates 53 and 53 are arranged so as to be movable along the axial direction of the cavity 5 by the elasticity of each O-ring 54. . That is, in the present embodiment, the pair of plates 53 and 53 are elastically moved in a direction in contact with the end face of the pipe material against the compressive force applied to the pipe material from the axial push punches 6 and 7, A seal mechanism 60 that functions to always bring the plates 53 and 53 into contact with the end face of the pipe is provided in the combined body 51 that constitutes the partition wall of the cavity 5.

  The procedure for molding using the hydroform molding die 50 having such a structure is completely the same as the procedure for molding using the hydroform molding die 1 of the first embodiment described above. Are the same. The outline is as follows.

(1) Two material pipes 13 and 14 are prepared (see FIG. 14A).
(2) The respective material pipes 13 and 14 are set in the mold body 4 and the mold body 4 is closed (see FIG. 14B).
(3) The axial push punches 6 and 7 are advanced while filling the material pipes 13 and 14 with fluid (for example, water) (see FIG. 14C).
(4) Pushing the shaft to a predetermined position while increasing the internal pressure (At this time, the plates 53 and 53 abut against the wall 55 which is the partition wall main body via the O-rings 54 and 54 at the final killing of the molding) Then, the molding is completed (see FIG. 14D).
(5) The completed part is taken out from the mold body 4 (see FIG. 14E).

  The hydroform molding die 50 as described above has the following advantages over the hydroform molding die 1 according to the first embodiment described above.

  In the hydroforming mold 1 according to the above-described first embodiment, a slight pressure leak occurs during molding at the portion in contact with the component end surface of the central partition wall (partition wall) 10, and There is a problem that it is necessary to repair or replace the mold when the mold is consumed or damaged due to repeated molding. That is, in the case of the hydroforming mold 1, the central partition (partition wall) 10 is worn out such as being damaged or deformed with repeated molding. If such wear occurs, pressure leakage (decrease in pressure in the material pipe) may occur at the partition wall during molding, or scratches may be transferred to the end face of the molded product. Replacement is required. Note that, even if the portion where the mold is consumed or damaged is polished, the dimensions of the parts change, so that the mold cannot be regenerated by polishing. In addition, even if the mold is not worn or damaged, when the material pipe expands due to internal pressure during molding, a phenomenon occurs in which the material pipe slightly shrinks in the axial direction. A pressure leak occurs. This pressure leak is eliminated in a short time because the material pipe is pushed by the continuous axial pushing, and the end face of the material pipe is properly sealed again (even if there is a slight pressure leak during molding). For example, parts can be molded without any problem), and fluctuations in internal pressure due to pressure leakage are undesirable because they cause variations in quality.

  On the other hand, in the hydroforming mold 50 according to the present embodiment, the central partition (partition wall) is constituted by a combined body 51 separate from the mold body 4, and the consumable part of the partition Since the wall surface is independent as a simple circular plate 53, when the hydroforming mold 50 is maintained, only the worn or scratched plate 53 needs to be replaced. Since it is not necessary to repair or replace the mold, the maintenance cost of the mold can be reduced. Further, when the material pipes 13 and 14 are first pushed by the axial push, the O-rings 54 and 54 installed inside the plates 53 and 53 are contracted, but the material pipes 13 and 14 are radially caused by the internal pressure. When inflating and contracting in the axial direction, the pair of plates 53, 53 can follow the end faces of the material pipes 13, 14 in a contact state (crimped state) until the O-rings 54, 54 return to the original state. The pressure leak at 51 can be surely prevented. Therefore, according to this hydroform molding die 50, it is possible to reliably prevent pressure leakage during molding, malfunction due to die wear and damage, and thereby due to pressure leakage during molding. It is possible to prevent defects such as molding defects and dimensional accuracy degradation, and it is possible to mold parts with very few molding defects and dimensional variations due to pressure leakage. Further, the hydroforming mold 50 can be molded by a normal hydroforming machine, and no modification of equipment is required.

  The second embodiment of the present invention has been described above, but the present invention is not limited to this embodiment, and various modifications and changes can be made based on the technical idea of the present invention. For example, in the hydroforming mold 50 according to the second embodiment, the O-rings 54 and 54 are used as elastic members for urging the pair of plates 53 and 53, but the same function is achieved in addition to that. A spring or the like may be used. Further, the present invention is applicable not only to the material pipes 13 and 14 having a circular cross section but also to pipe materials having various cross sectional shapes such as a rectangular cross section and an elliptical cross section. It is possible. Further, the present invention can be applied to a case where three or more adjacent cavities are provided via a partition wall made of the combination 51 and three or more molded parts are simultaneously molded by one hydroform molding operation. .

  When it is necessary to expand the end portion of the pipe material on the center side of the mold, this flow hole is formed around the flow hole 57 on the side surface of the partition wall 55 described above (the side surface corresponding to the end surface of the pipe material). An inclined surface (an inclined surface 20 as shown in FIGS. 7 and 8) that is inclined toward the outer peripheral side of the cavity 5 (side away from the axis of the cavity 5) as it approaches 57 may be provided, or the side surface of the plate An inclined surface (inclined surface 23 as shown in FIG. 10 (b)) that inclines toward the outer peripheral side of the cavity 5 as it approaches the flow hole 57 at a location around the flow hole 56 on the side surface corresponding to the end surface of the pipe material. May be provided.

It is sectional drawing which shows the structure of the metal mold | die for hydroforming which concerns on the 1st Embodiment of this invention. It is a flowchart which shows the procedure which enforces the hydroform shaping | molding method which concerns on one Embodiment of this invention using the metal mold | die for hydroform shaping | molding of FIG. 3A to 3E are cross-sectional views showing a procedure for hydroforming a material pipe (pipe material) using the hydroforming mold shown in FIG. It is sectional drawing which shows the dimensional relationship between the metal mold | die for hydroforming, and a material pipe. It is sectional drawing which shows the state which shape | molded the material pipe with the metal mold | die for hydroforming. It is sectional drawing explaining the state of the seal leak which arises when expanding the edge part of a material pipe in the metal mold | die center side. It is sectional drawing of the principal part of a metal mold | die at the time of providing the inclined part which has an inclined surface in a partition. It is sectional drawing which shows the dimensional relationship at the time of providing the inclination part which has an inclined surface in a partition. It is sectional drawing which shows the state which has arrange | positioned the pipe expansion piece in the position used as a partition. FIG. 10A is a front view of the pipe expansion piece, and FIG. 10B is a cross-sectional view of the pipe expansion piece. FIG. 2 is an enlarged cross-sectional view of a molded part obtained using the hydroform mold of FIG. 1. It is sectional drawing which shows the structure of the metal mold | die for hydroform molding which concerns on the 2nd Embodiment of this invention. 13A is an enlarged sectional view taken along line XX in FIG. 12, and FIG. 13B is a sectional view taken along line YY in FIG. 14A to 14E are cross-sectional views showing a procedure for hydroforming a material pipe (tube material) using the hydroforming mold shown in FIG. It is sectional drawing which shows the structure of the conventional metal mold | die for hydroforming. It is a flowchart which shows the procedure which performs hydroform shaping | molding using the conventional metal mold | die for hydroform shaping | molding. It is sectional drawing which shows sequentially the procedure which hydroform-molds a material pipe (tube material) using the conventional metal mold | die for hydroforming.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mold for hydroforming 2 Lower mold 3 Upper mold 4 Mold main body 5 Cavity 5a, 5b Cavity 6, 7 Axial push punch 8, 9 Partition wall 10 Partition 11 Flow hole 12 Fluid supply hole 13, 14 Material pipe 13 ', 14' Molding parts 15 Fluid 16, 17 Swelling part (expanded part)
DESCRIPTION OF SYMBOLS 20 Inclined surface 21 Pipe expansion top 22 Inclined part 23 Inclined surface 24 Inclined part 50 Hydroform molding die 51 Combination 52 Top 53 Plate 54 O-ring 55 Wall part 56, 57, 58 Flow hole 60 Sealing mechanism

Claims (16)

  In the hydroforming mold, the mold includes a partition wall that divides the cavity into a plurality of parts, and a fluid is movable in the plurality of cavities partitioned by the partition wall by providing a flow hole in the partition wall. Hydroform molding die characterized by   In the hydroforming mold, the mold includes a plurality of cavities, and a flow hole is provided in a partition wall between the plurality of adjacent cavities so that fluid can move in the plurality of cavities. Hydroform molding die characterized by   The hydroform molding die according to claim 1 or 2, further comprising a shaft pressing punch that advances in the cavity toward the partition wall.   The axial push punch is disposed at each end of the mold opposite to the partition in the plurality of cavities, and the fluid is movable through a flow hole provided in the partition. The hydroforming mold according to claim 3, wherein the molds are configured to advance in a direction approaching each other.   5. The cavity includes a plurality of surfaces whose inner diameter changes intermittently or continuously, and a surface having the smallest inner diameter among the plurality of surfaces is adjacent to the partition wall. The hydroforming mold according to any one of the above.   The wall surface of the partition wall that comes into contact with the end face of the pipe material that is a molding target member is constituted by a plate separate from the mold body composed of the lower mold and the upper mold, and the plate is detachable. The mold structure for hydroform molding according to any one of claims 1 to 5.   Resisting the compressive force applied to the tube material from the axial push punch, the plate is elastically moved in a direction to contact the end surface of the tube material so that the plate is always in contact with the end surface of the tube material. The mold structure for forming a hydroform according to claim 6, wherein the partition wall is provided with a functioning sealing mechanism.   The sealing mechanism is configured by a main body portion of the partition wall, the separate plate, and an elastic member interposed between the main body portion of the partition wall and the separate plate, and the separate plate is 8. The hydroforming mold structure according to claim 7, wherein the mold is movable by elasticity of the elastic member.   The inclined surface which inclines to the outer peripheral side of the said cavity is provided in the circumference | surroundings location of the said flow hole on the surface of the said partition as the said flow hole is approached. Mold for hydroform molding.   The hydroforming mold according to claim 9, wherein a separate pipe expansion piece that does not move with the mold when the mold is opened and closed is provided, and the inclined surface is provided on the pipe expansion piece. Mold.   The hydroforming mold according to any one of claims 1 to 10, wherein the plurality of cavities are formed in a bilaterally symmetric shape with the partition wall as a symmetric center.   In a hydroform molding method for simultaneously molding a plurality of pipe materials, a pipe material is disposed in each of a plurality of cavities partitioned by a partition wall in a mold, the inside of the tube material is filled with a fluid, and the fluid is provided in the partition wall. Hydroform molding characterized in that a plurality of pipe materials in the plurality of cavities are simultaneously molded by applying pressure to the fluid under a condition in which the fluid can be moved between the plurality of pipe materials through the flow holes. Method.   13. The hydrostatic press according to claim 12, wherein a shaft pushing punch disposed at a mold end opposite to the partition in the cavity is advanced toward the partition while applying pressure to the fluid. Foam molding method.   The hydroforming method according to claim 12 or 13, wherein the end face of the pipe material is chamfered in advance and then placed in the cavity.   15. The region according to any one of claims 12 to 14, wherein a region that does not cause the pipe expansion is arranged adjacent to the partition wall among a region that causes the pipe expansion when the tube material is formed and a region that does not cause the pipe expansion. The hydroform molding method as described in 2.   When the inner diameter of the inner surface of the cavity changes intermittently or continuously, an end surface of a pipe member having an outer diameter substantially the same as the inner diameter of the inner surface of the cavity adjacent to the partition wall is disposed in contact with the partition wall. The hydroform molding method according to any one of claims 12 to 15, wherein

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