JP4415826B2 - Hydraulic bulge molding method, hydraulic bulge molding device, and hydraulic bulge molded product - Google Patents

Description

  The present invention relates to a hydraulic bulge molding method, a hydraulic bulge molding apparatus, and a hydraulic bulge molded product.

As a forming technique for a hollow member used for a vehicle structural material or the like, hydraulic bulge forming is generally performed. In this molding method, a sealed molding material is mounted on a mold in which a part shape is dug, and the molding material is inflated by applying hydraulic pressure in the molding material to form a shape that matches the cavity. A member processed by this hydraulic bulge method may be used as a single unit, but when a fastening nut is provided to connect with other parts, a part of the member is cut and a weld nut is welded. Alternatively, processing such as welding a bracket, which has been previously welded with a nut, to the member is performed (for example, see Patent Document 1).
JP 2000-168618 A

  However, in order to cut the processed member, generally, machining, plasma cutting, laser cutting, or the like is required, so that the number of processing steps increases and productivity is deteriorated. In addition, when the bracket is welded to the processed member, the number of parts increases, which is disadvantageous in terms of manufacturing cost, and also increases the facility cost and the processing man-hour, which causes the productivity to deteriorate.

  The present invention has been made in order to solve the problems associated with the above-described conventional technology, and can reduce the equipment cost and improve the productivity, the hydraulic bulge molding method, the hydraulic bulge molding apparatus, and the hydraulic pressure The object is to provide a bulge molded product.

  The hydraulic bulge forming method according to the present invention that achieves the above object is the method of manufacturing a hydraulic bulge molded product having a flange by preliminarily forming a pipe material as a molding material and then applying hydraulic pressure to the inside of the pipe material. A bulge forming method, wherein a preforming step of preliminarily crushing the tube material to produce a preformed product, and a liquid is formed while holding the flange after forming the flange by partially pressing the preformed product. A hydraulic bulge forming step for expanding the preform by applying pressure to the inside of the preform, and a drilling step for punching the flange end that is a folded portion formed at the end of the flange It is characterized by having.

  The hydraulic bulge forming apparatus according to the present invention that achieves the above-described object comprises a preforming mold for preforming a pipe material that is a molding material, and a partial press on a preform formed by the preforming mold. And forming a flange, and a hydraulic bulge molding device having a hydraulic molding die for adding hydraulic pressure to the inside of the preform while holding the flange, after the hydraulic bulge molding, It has a cutting blade for drilling which can move back and forth along the crushing surface of the flange with respect to the flange end which is a folded portion formed at the end of the flange.

  The hydraulic bulge molded product according to the present invention that achieves the above object is formed by partially crushing a tube material that is a molding material to form a flange, and inside the flange end portion that is a folded portion formed at the end portion of the flange. And a paint countermeasure hole penetrating along the crushing surface of the flange from the outside of the flange end toward the gap.

  Since the present invention configured as described above forms a flange by preforming, there is no need to attach a bracket after hydraulic bulge molding, and productivity can be improved and processing man-hours can be reduced. In addition, since a coating countermeasure hole is provided at the end of the flange, it is possible to provide a good member by preventing coating failure such as paint pooling and preventing water pooling inside the member.

  Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment>
FIG. 1 is an overall perspective view of a final molded product according to the first embodiment, and FIG. 2 is an enlarged perspective view of a main part of FIG.

  In the hydraulic bulge forming method of the present invention, after preforming the pipe material P1 which is a forming material (preforming step), the preform 1 obtained by this preforming is partially pressed to press the flange 1 A folded portion formed at the end of the flange 1 that is molded and formed by expanding the preform P2 by applying a hydraulic pressure to the preform P2 while holding the flange 1 (a hydraulic bulge forming step). This is a method of forming the final molded product P4 shown in FIGS. 1 and 2 by punching the flange end 2 (drilling step).

  FIG. 3 is a longitudinal sectional view of a hydraulic bulge forming apparatus showing a preforming process according to the first embodiment, in which FIG. 3 (A) is before the preforming process, and FIG. 3 (B) is during the preforming process. FIG. 3C is a view after the preforming step, and FIG. 4 is a longitudinal sectional view showing an example in which the preforming is not performed. FIG. 4A is before the forming step, and FIG. FIG. 4C is a diagram showing the after the molding process.

  First, in the preforming step, the pipe material P1 is disposed in the preforming mold 3 as shown in FIG. This pipe material P1 is, for example, a metal pipe in the present embodiment, but is not limited to metal.

  The preforming mold 3 has a pair of upper and lower preforming molds 3A and 3B, and the preforming upper mold 3A and the preforming lower mold 3B are relatively separated from each other. After the pipe member P1 is installed inside (see FIG. 3A), the pre-forming upper die 3A and the pre-forming lower die 3B are relatively brought close to each other by a pressing device (not shown) to press the pipe member P1 ( (See FIG. 3B). The inner walls of the preforming upper mold 3A and the preforming lower mold 3B are provided with projecting mold surfaces 4A and 4B that are adjacent to each other leaving a predetermined narrow gap when the molds are closed. When the projecting mold surfaces 4A and 4B come close to each other, the pipe material P1 is pressed, and the rough flange portion 5 that finally becomes the flange 1 is preformed (see FIG. 3C). At this time, the pipe material is not completely crushed in the rough flange portion 5, and a predetermined gap is provided between the upper and lower plate materials.

  A side wall surface 6 that extends in the vertical direction (pressing direction) and is formed relatively long is formed at the side end of the lower mold 3B for preforming opposite to the protruding mold surface 4B in the horizontal direction. The end of the upper mold 3 </ b> A moves up and down along the side wall surface 6. For this reason, the pipe P1 is pressed by the projecting mold surfaces 4A and 4B when pressed, and tends to escape in the direction in which the side wall surface 6 is provided. The When such a side wall surface 6 is not provided, for example, when the pipe material is pressed with a mold as shown in FIG. 4, the pipe material P <b> 1 moves (see FIG. 4B), and the comic part 7 sandwiched between the upper and lower molds becomes (See FIG. 4C), and the amount of movement of the pipe material P1 cannot be predicted, so it is difficult to make the length of the flange uniform. However, in the case of this embodiment, the movement of the pipe material P1 is restrained by the side wall surface 6, so that the crisp part 7 is not generated, the length of the flange portion 2 can be made uniform, and proper pre-molding is possible.

  After the preforming process, the preform P2 is taken out from the preforming molds 3A and 3B and installed in the hydraulic molding mold 8 to perform the hydraulic bulge forming process.

  FIG. 5 is a longitudinal sectional view of a hydraulic bulge forming apparatus showing a hydraulic bulge forming process according to the first embodiment. FIG. 5 (A) is before the hydraulic bulge forming process, and FIG. During the pressure bulge forming process, FIG. 5C is a view after the hydraulic bulge forming process, and FIG. 6 is a longitudinal sectional view showing a longitudinal end portion of the hydraulic bulge forming apparatus according to the first embodiment. .

  The hydraulic molding die 8 includes a hydraulic molding upper die 8A and a hydraulic molding lower die 8B which are relatively close to each other. The upper mold 8A for hydraulic molding and the lower mold 8B for hydraulic molding have a mold surface corresponding to the shape of the final molded product P4, and the flange pressing portion 9A is located at a position corresponding to the rough flange 5 of the preform P2. , 9B. When both molds are closed, the flange pressing portions 9A and 9B become surfaces that are close to each other with a gap corresponding to the final thickness of the flange 1 that is finally formed (see FIG. 5C).

  Further, a concave groove 10 is formed along the longitudinal direction of the preform P2 at the outer end of the flange pressing portion 9A of the upper mold 8A for hydraulic molding, and is formed in the preform P2. An end portion of the flange portion 5 is formed by the concave groove 10. The shape of the concave groove 10 may have a predetermined curvature or other shapes. Further, it may be formed on the lower mold 8B for hydraulic molding.

  As shown in FIG. 6, a nozzle 11 for applying a hydraulic pressure to the inside of the preform is inserted into the longitudinal end of the preform P2.

  After the upper mold 8A for hydraulic molding and the lower mold 8B for hydraulic molding are separated from each other and the preform P2 is placed in the mold (see FIG. 5A), the hydraulic pressure is applied by a pressing device (not shown). The molding upper mold 8A and the hydraulic molding lower mold 8B are brought relatively close to each other, and the preform P2 is pressed by the flange pressing portions 9A and 9B (see FIG. 5B). Since the preform P2 is formed in a shape that coincides to some extent with the hydraulic molding die 8 by the preforming process, the preform P2 does not escape from the die, and the kamikomi portion 7 is not formed. A flange 1 having a desired shape and dimension is formed. At this time, the flange end portion 2 is accommodated in the concave groove 10, and the gap portion H is formed without being completely crushed. Since the flange end portion 2 is folded back, there is a possibility of breaking when the tensile strength of the pipe material P1 is high. In this embodiment, a gap H corresponding to the plate thickness of the pipe material P1 is provided. Thus, it is possible to prevent breakage at the folded portion.

  Thereafter, as shown in FIG. 6, the nozzle 11 is inserted into the longitudinal end portion of the preform P <b> 2, and the hydraulic pressure flows into the inside through the inlet 12. As a result, the preform P2 is swelled into a shape corresponding to the inner walls of the hydraulic molding dies 8A and 8B (see FIG. 5C). In addition, it is set as the structure which can move the nozzle 11 inside a metal mold | die while injecting hydraulic pressure, the preform P2 is pressed from a side surface, and the material of preform P2 itself flows in into a mold. Can be promoted.

  At the time of applying the hydraulic pressure, the flange 1 of the preform P2 is pressed and fixedly held by the flange pressing portions 9A and 9B, and the dimensions of the flange 1 hardly change by applying the hydraulic pressure. The flange 1 can be formed in a desired shape with high accuracy.

  Next, a hydraulic bulge molded product P3 formed by hydraulic bulge molding is taken out from the hydraulic molding die 8 and held, and a hole penetrating from the outside of the flange end 2 to the gap H in the direction along the flange surface. Perform the opening process.

  FIG. 7 is a perspective view showing the cutting blade for drilling according to the first embodiment, and FIG. 8 is a longitudinal sectional view for explaining the drilling process according to the first embodiment, and FIG. FIG. 8B is a diagram showing a state after the drilling process, and FIG.

  The drilling step is performed by a drilling blade 13 as shown in FIGS. The hole cutting blade 13 has a wedge shape with a sharp side close to the flange end 2 and has a blade having a predetermined length in a direction along the flange end 2 (pipe material longitudinal direction). As shown in FIG. 8, the hole-cutting blade 13 can advance and retreat with respect to the outer side of the flange end 2, and the gap H extends in the direction along the flange surface from the outer side of the flange end 2 in the direction intersecting the flange surface. It penetrates so as to spread (see FIG. 8B), and forms a slit-shaped paint countermeasure hole 14 along the flange end 2. In the drilling step, for example, if a hole is to be drilled from the direction intersecting with the flange surface, the gap H is crushed and it is difficult to open the hole, but in this embodiment, from the outside of the flange end 2. Since the hole is drilled in the direction along the flange surface, the paint countermeasure hole 14 can be reliably provided.

  Thereafter, a mounting hole 15 penetrating in the direction intersecting the surface of the flange 1 is formed in the flange 1 by machining, and the final molded product P4 is completed (see FIG. 2).

  Since the final molded product P4 formed according to the present embodiment is provided with the paint countermeasure hole 14, the extra paint is discharged, and the paint is uniformly attached with an appropriate thickness without causing an air pocket or a paint reservoir. . For this reason, it is possible to produce a good hydraulic bulge molded product in which water accumulation or the like hardly occurs and corrosion or the like hardly occurs.

  Normally, when the gap H is provided, paint defects such as air pockets and paint pools are generated at that portion. When air pockets are generated, the inflow of paint into the gap H and the discharge of excess paint are hindered, and coating defects such as nonuniform coating tend to occur. Such a coating failure causes a pool of water in the coating portion, and thus causes factors such as corrosion of the member. However, the final molded product P4 of the present embodiment does not have such problems and is a good molded product.

<Second Embodiment>
In the second embodiment, the preforming step and the hydraulic bulge forming step are performed with a common double-action mold.

FIG. 9 is a longitudinal sectional view showing a hydraulic bulge forming apparatus according to the second embodiment, where (A) is before the preforming step, (B) is after the preforming step, and (C) is the hydraulic bulge forming. (D) is a figure which shows a hydraulic bulge forming process after a process.
In addition, about the member which has the same function as 1st Embodiment, the same code | symbol is used and the description is abbreviate | omitted in order to avoid duplication.

  The double-acting mold 16 according to the second embodiment includes a pair of upper and lower double-acting upper mold 16A and double-acting lower mold 16B, and a punch that can advance and retract separately in the same direction as the double-acting upper mold 16A. 17.

  The double-acting lower die 16B is provided with a protruding die surface 4B for forming a flange on the pipe material, and a punch 17 is provided above the protruding die surface 4B.

  Further, a concave groove 10 is formed at the outer end of the punch 17 along the longitudinal direction of the pipe P1, and a flange end 2 finally formed in the pipe P1 is formed in the concave groove 10. Match.

  First, the pipe material P1 is installed inside the mold (see FIG. 9A), and the double-action type upper die 16A and the punch 17 are moved together by a predetermined amount with respect to the double-action type lower die 16B to make the pipe material P1. The preforming step is performed to form a preform P2 (see FIG. 9B). However, as in the first embodiment, the constricted flange portion 5 of the pipe material P1 is not completely crushed, but is preformed with a predetermined interval left. Thereafter, the punch 17 is moved close to the double-acting lower mold 16B while the double-acting upper mold 16A is fixed, and the preform P2 is crushed to form the flange 1 (see FIG. 9C). . At this time, the flange end portion 2 is housed in the concave groove 10 and has a gap portion H inside without being completely crushed.

  Thereafter, a hydraulic bulge forming (see FIG. 9D) and a hole-drilling process are performed, which are omitted because they are the same as those in the first embodiment.

<Third Embodiment>
In the third embodiment, a drilling process is performed in the mold after the hydraulic bulge molding process, and the processes up to the hydraulic bulge molding are the same as those in the first or second embodiment.

  FIG. 10 is a longitudinal sectional view showing a hydraulic bulge forming apparatus according to the third embodiment.

  As shown in FIG. 10, an insertion hole 19 is formed from the side surface of the hydraulic molding dies 18A, 18B to the side surface where the flange pressing portions 9A, 9B are formed. A closing member 20 having a tip portion forming an inner wall continuous with the inner wall of the mold 18 is inserted. The closing member 20 is integrally connected to the mold until the hydraulic bulge forming process is completed, and is extracted after the hydraulic bulge forming process is completed. Thereafter, the punching cutting blade 13 is inserted from the insertion hole 19, and the flange end 2 is punched in the same manner as in the first embodiment. Further, the insertion hole 19 is not necessarily provided between the upper mold 18A for hydraulic molding and the lower mold 18B for hydraulic molding. Depending on the shape of the mold, for example, the upper mold 18A for hydraulic molding or the hydraulic pressure is used. You may form in the lower mold | type 18B for shaping | molding.

  The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the claims. For example, although the paint countermeasure hole provided by the present embodiment is slit-like, any shape may be used as long as the paint can be removed, and the shape of the drilling blade may be changed to another shape.

1 is an overall perspective view of a final molded product according to a first embodiment. It is an expansion perspective view of the principal part of FIG. It is a longitudinal cross-sectional view of the hydraulic bulge shaping | molding apparatus which shows the preforming process which concerns on 1st Embodiment, (A) is before a preforming process, (B) is in a preforming process, (C) is a preforming process. FIG. It is a longitudinal cross-sectional view which shows the example when not performing preforming, Comprising: (A) is a figure before a formation process, (B) is a formation process, (C) is a figure which shows a formation process. It is a longitudinal cross-sectional view of the hydraulic bulge shaping | molding apparatus which shows the hydraulic bulge shaping | molding process which concerns on 1st Embodiment, (A) is before a hydraulic bulge shaping | molding process, (B) is during a hydraulic bulge shaping | molding process. (C) is a view showing a state after the hydraulic bulge forming step. It is a longitudinal cross-sectional view which shows the longitudinal direction edge part of the hydraulic bulge forming apparatus which concerns on 1st Embodiment. It is a perspective view which shows the cutting blade for drilling which concerns on 1st Embodiment. It is a longitudinal cross-sectional view for demonstrating the drilling process which concerns on 1st Embodiment, (A) is a figure before a drilling process, (B) is a figure which shows after a drilling process. It is a longitudinal cross-sectional view which shows the hydraulic bulge shaping | molding apparatus which concerns on 2nd Embodiment, (A) is before a preforming process, (B) is after a preforming process, (C) is during a hydraulic bulge shaping process, (D) is a view showing the hydraulic bulge forming step. It is a longitudinal cross-sectional view which shows the hydraulic bulge shaping | molding apparatus which concerns on 3rd Embodiment.

Explanation of symbols

1 flange,
2 flange end,
3A Upper mold for preforming,
3B Mold for molding,
4A, 4B Projection type surface,
5 Coarse burden time part,
6 Flanges,
7 Comic club,
8A, 18A Upper mold for hydraulic molding,
8B, 18B Lower mold for hydraulic forming,
9A, 9B Flange pressing part,
10 groove,
11 nozzles,
12 Inlet,
13 Cutting blade for drilling,
14 Paint hole,
15 mounting holes,
16A Double-acting type upper mold,
16B Double acting lower mold,
17 Punch,
19 Insertion hole,
20 closing member,
H gap,
P1 tubing,
P2 preformed product,
P3 Hydraulic bulge molded product,
P4 Final molded product.

Claims (11)

A hydraulic bulge molding method for manufacturing a hydraulic bulge molding product having a flange by preliminarily molding a pipe material which is a molding material and then adding a hydraulic pressure to the inside of the pipe material,
A preforming step of preliminarily crushing the tube material to prepare a preform;
After forming the flange by partially pressing the preform, a hydraulic bulge forming step of expanding the preform by adding hydraulic pressure to the interior of the preform while holding the flange;
A hydraulic bulge forming method comprising: a hole making step of making a hole in a flange end portion which is a folded portion formed at an end portion of the flange.   The hydraulic bulge forming method according to claim 1, wherein a gap portion is provided in the flange end portion.   3. The hydraulic pressure according to claim 1, wherein in the drilling step, the hydraulic pressure is formed in a direction along a crushed surface of the flange so as to penetrate from the outside of the flange end portion to a gap portion inside the flange. Bulge molding method.   The hydraulic bulge forming method according to any one of claims 1 to 3, wherein in the step of drilling, the hole is formed by expanding the hole in a direction intersecting with the crushed surface of the flange.   5. The hydraulic bulge forming method according to claim 1, wherein the drilling step is performed in a hydraulic molding die used in the hydraulic bulge forming step.   The hydraulic bulge forming method according to any one of claims 1 to 5, wherein an attachment hole penetrating in a direction intersecting the surface of the flange is formed in the flange after the drilling step. . A preforming mold for preforming a tube material, which is a molding material, and a preform formed by the preforming mold are partially pressed to form a flange, and a hydraulic pressure is applied while holding the flange. A hydraulic bulge molding device having a hydraulic molding die to be added to the interior of the preform,
A hydraulic pressure characterized by having a cutting blade for drilling that can be moved back and forth along the crushing surface of the flange with respect to the flange end which is a folded portion formed at the end of the flange after hydraulic bulge forming Bulge forming device.   The hydraulic bulge forming apparatus according to claim 7, wherein a tip of the cutting blade for drilling is wedge-shaped.   The preforming mold and the hydraulic molding mold are a common double-action mold, and the double-action mold is a double-action upper mold and a double-action mold lower mold that are relatively close to each other. And a punch that is provided on the double-acting upper mold and can be moved close to and away from the double-acting lower mold independently of the double-acting upper mold. The hydraulic bulge forming device described in 1. The hydraulic molding die has an insertion hole that penetrates from the hydraulic molding die to a portion where the flange end is installed, and a closing member that can be inserted into and removed from the outside of the insertion hole,
The hydraulic bulge forming apparatus according to any one of claims 7 to 9, wherein the drilling blade for drilling is insertable into the insertion hole.   A tube material that is a molding material is partially crushed to form a flange, and a gap portion is formed inside the flange end portion that is a folded portion formed at the end portion of the flange. A hydraulic bulge molded product having a paint countermeasure hole penetrating along the flange crushing surface toward the part.

Images