JP4730164B2 - Hydraulic bulge parts with flange - Google Patents

Description

  The present invention relates to a hydraulic bulging part provided with a flange for joining other parts.

  A tubular material made of metal, or a prefabricated tubular material (hereinafter abbreviated as a metal element tube) is set in a pair of upper and lower molds, and pressure is applied to the liquid introduced into the element tube. In response to this, a hydraulic bulging process is applied to obtain a molded product that conforms to the internal shape of the mold by applying a compressive force in the axial direction from the end of the raw tube to obtain a molded product that conforms to the internal shape of the mold. Used in the manufacture of cross-section products.

  A product formed by this hydraulic bulge processing (hereinafter referred to as a hydraulic bulge processing part) may be used as a single part, but is often used in combination with other parts. Typical coupling methods include welding and detachable bolt fastening.

  By the way, when manufacturing what is similar to the said hydraulic bulge processing part by press-molding a metal plate, the method of carrying out spot welding combining two press-molded members and making it a closed cross-section structure is taken.

  FIG. 1 is a perspective view showing an example of a flanged part produced by press-molding a metal plate. FIG. 1 (a) shows a state where other parts are joined by spot welding, and FIG. 1 (b) shows a bolt. Shows the combined state.

  When a part having a closed cross-sectional structure is manufactured by press molding, the two members 1a and 1b that are press-molded are combined, and the flanges 2 are spot welded 4a to fix the two members. Using this flange, spot welding 4b can be performed with other parts as shown in FIG. 1 (a), or can be joined by bolt fastening 5 as shown in FIG. 1 (b).

  On the other hand, in the case of a hydraulic bulge processed part manufactured from a metal base tube, there is generally no flange. However, as a method of providing a flange on a hydraulic bulge processed part, there are the following methods.

  FIG. 2 is a perspective view showing a state in which other parts are joined to the hydraulic bulge processing part, FIG. 2 (a) shows a state joined by arc welding, and FIG. 2 (b) shows a state joined by bolts. .

  FIG. 2A shows an example in which another component 3 is joined to the hydraulic bulge processing component 1 by direct arc welding 7a.

  In addition, as shown in FIG. 2B, in the case of bolt fastening, it is necessary to attach the bracket 6 to the component 1 by arc welding 7b. Arc welding is less productive than spot welding, and the dimensional accuracy of the product may deteriorate due to heat during welding.

  As another method, Patent Document 1 discloses a method in which a part of a wall portion of a predetermined part of a hydraulic bulge processing part is cut and bent outward to form a flange.

  FIG. 3 is a perspective view for explaining the method disclosed in the publication. As shown in the figure, this method is a method in which a slit is formed in a part of the wall portion 8 of the hydraulic bulge processing part 1 and then bent outward to form the flange 2. The other component 3 is joined to this flange by spot welding.

  However, this method has the following two problems.

  The first problem is that an opening is provided in the side wall, so that the strength and rigidity of the hydraulic bulge processed part are significantly reduced.

  The second problem is that the bending process after providing the cut is troublesome because it is difficult to put a tool into the hydraulic bulging part.

  Patent Document 1 discloses a method of forming a part of a material to be formed between upper and lower molds during hydraulic bulge processing.

  FIG. 4 is a cross-sectional view for explaining a method of forming a flange at the time of hydraulic bulge processing shown in Patent Document 1, and FIG. 4A is lowered to the raw tube 10 set in the lower die 11. FIG. 4B shows a state in which the upper mold 12 is in contact, and FIG. 4B shows a state in which the material is buckled or waist-folded in a state where the upper mold is further lowered, and the protruding portion 13 of the material is generated. c) shows a state in which the upper and lower molds are in close contact and the protruding portion is crushed to the close contact state.

  As is apparent from FIG. 4, this method uses a biting phenomenon that occurs in the process of closing the upper and lower molds, which is a preparation stage for hydraulic bulging. However, this method has three problems.

  The first problem is that the flange width f is limited. That is, if the outer diameter D of the raw tube 10 is constant, the relationship is such that f decreases if the product width W excluding the flange is large. Therefore, regardless of the product width W, the target width f cannot be determined.

  The second problem is that the flange width f varies due to the influence of the strength of the material and the friction of the mold because of utilizing the biting phenomenon of the raw tube.

  The third problem is that a flange cannot be provided in a part of the product because the biting phenomenon is used, and if the flange is provided in a part of the product, the product shape is restricted.

  FIG. 5 is a diagram for explaining the third problem, and FIG. 5A is a perspective view of the product when a flange is provided on a part of the product by the method described in Patent Document 1. FIG. FIG. 5B is a perspective view of the product when a flange is provided in a part of the product without changing the shape of the product.

  In the method described in Patent Document 1, a flange cannot be formed on a part of a side wall of a product having a constant width W as shown in FIG. That is, in order to form a flange in a part of the raw pipe by biting out, the outer circumference of the raw pipe is constant, so that the product width W1 of the part where the flange is formed is set as shown in FIG. This is because the width must be smaller than W2 and W3. Thus, in the above method, the product shape is affected by the presence or absence of the flange.

Japanese Patent Laid-Open No. 11-170060

  An object of the present invention is to provide a hydraulic bulge processing part having a flange having an arbitrary shape and size.

  As a result of various experiments and studies to solve the above problems, the present inventors have obtained the following knowledge.

  a) After bulging the part where the flange is to be formed while hydraulic bulging the metal element tube, the expanded part is crushed with a punch to stabilize it to any size and shape projecting from the expanded part. And can be flanged.

 b) Once the metal tube is bulged into a flange-free shape, and a portion of the bulging portion is crushed with a punch, a stable flange can be formed inside the bulging portion in any size and shape. .

  The present invention has been made on the basis of such knowledge, and the gist of the flanged hydraulic bulge processing parts shown in the following (1) and (2).

( 1 ) A hydraulic bulge processing part having a flange for joining other parts protruding outside from a bulging part formed by hydraulic bulging, the flange constituting the bulging part A flanged hydraulic bulge processing part, characterized in that a flange is formed by crushing and molding a part of the material being bulged and having ribs at one or both ends of the flange.

( 2 ) The flanged hydraulic bulge processing part according to (1 ) above, wherein the rib is for improving the strength and rigidity of the flange.

  According to the present invention, flanges of any shape and size that can be spot welded and bolted to other parts can be formed during the process of hydraulic bulging and are required at any location of hydraulic bulging parts. Hydraulic bulge parts with minimum flanges can be obtained.

  Hereinafter, the present invention will be specifically described.

  FIG. 6 is a view for explaining a method of forming a flanged hydraulic bulge processing part protruding outward from a bulge formed by bulging, and FIG. 6 (a) shows a material set in a mold. Fig. 6 (b) shows a state in which the flange forming part is bulged, Fig. 6 (c) shows a state in which the upper and lower punches are advanced to form the flange, and Fig. 6 (d) shows the final state after increasing the hydraulic pressure. It is a figure which shows the state final-molded to the product shape.

  As shown in FIG. 6 (a), the mold used for forming the hydraulic bulge processing part of the present invention has a space 21 having the same shape as the external shape of the product and a flange forming scheduled portion 24 of the metal base tube. And a punch 23 that can be moved forward and backward toward the space 22.

  In this example, punches are provided in the upper and lower molds. However, depending on the portion where the flange is provided or the shape of the flange, the punch may be provided on only one side of the upper and lower molds.

  The shape of the punch and the die that form the space portion 22 for bulging to form the flange is not particularly limited, and may be matched to the shape of the target flange. In order to easily obtain a large bulge amount, it is preferable to make the height of the bulge portion as large as possible.

  FIG. 7 is a diagram showing various shape examples of the bulging portion. FIG. 7A shows the case where the height H of the bulging portion is the same as the height of the product after molding, and FIG. 7 (c) shows that one side of the bulging part is the same as one side of the product, and FIG. 7 (d) shows that the height H of the bulging part is the height of the product. It is a figure which shows the case where it is the same as that, and the shape is rounded. As shown in FIG. 7, the shape of the bulging portion can be arbitrarily changed by variously changing the space of the bulging portion.

  The processing steps will be described with reference to FIG. The upper die 12 incorporated in a hydraulic bulge processing apparatus (not shown) is raised to set the metal base tube 21 in the hole die of the lower die 11, and as shown in FIG. Lower and contact the lower mold. Next, as shown in FIG. 6 (b), pressure is applied to the liquid introduced into the metal base tube, and the bulging process is performed on the cross-section of the flange forming planned section while performing the hydraulic bulge processing on the product shape The part 25 is molded. Thereafter, the hydraulic pressure is lowered to advance the punch 23 built in the upper and lower molds, and the bulging portion 25 is processed to form the flange 26 as shown in FIG.

  In this case, the flange may be formed by advancing the punch without lowering the hydraulic pressure even after bulging. However, if the punch is advanced and crushed while the hydraulic pressure is high, material breakage tends to occur, and the flange width after crushing may not be able to be increased, and a large pressure is required for the crushing process. . Therefore, it is desirable to perform the crushing process after reducing the hydraulic pressure. When the hydraulic pressure is lowered and the punch is advanced and crushed, the deformation is not limited to the bulging portion, and the hydraulic bulge processed product body is also deformed and deformed as shown in FIG.

  Finally, as shown in FIG. 6 (d), the hydraulic pressure in the workpiece is increased while the flange portion is pressed with a punch, and parts other than the flange portion are reshaped to finish the product.

  It should be noted that the load necessary for the punch needs to be sufficient to prevent the punch from being lifted by the hydraulic pressure in the process of crushing the bulging portion and finishing the product into the product shape shown in FIG. 6 (d).

  Next, although it is the shape of a flange, what is necessary is just to make it the shape which is easy to join according to the shape of the other components couple | bonded. In addition, since the shape of the flange is determined by the shape of the space formed by the punch and the mold when the bulging portion is crushed by the punch, the punch and the metal are formed so as to be a space for flange formation. The shape of the mold can be determined.

  FIG. 8 is a view showing an example of the shape of the flange, FIG. 8 (a) is a perspective view of a processed part having a simple flange, and FIG. 8 (b) is a processed part with a flange having ribs on two sides of the flange. FIG.

  When it is desired to increase the rigidity and strength of the flange, as shown in FIG. 8B, a flange having ribs 31 at both ends in the longitudinal direction of the flange may be used.

  FIG. 9 is a view showing an example of the shape of the rib, FIG. 9A is a view showing the AA cross section of FIG. 8B, a flange having ribs on both sides, and FIG. 9B is an upper surface of the flange. FIG. 9C shows a flange having a rib only at one end of the flange. Such a shape may be determined by the strength and rigidity required for the rib.

  In forming the flange with the rib, the punch and the mold may be designed so that a space corresponding to the thickness of the rib is formed between the punch and the mold when the bulging portion is crushed by the punch. In other words, only the portion that becomes the flange of the bulging portion is partially crushed with a punch.

  FIG. 10 is a view for explaining a method of forming a hydraulic bulge processing part having a flange inside the bulging portion formed by bulge processing. 10 (a) shows a state in which a material is set in a mold, FIG. 10 (b) shows a state in which a flange formation planned portion is bulged into a shape without a flange by hydraulic bulging, and FIG. FIG. 10D is a diagram showing a state in which the inner pressure is lowered and the upper and lower crushing punches are advanced to form the flange, and FIG.

  As shown in FIG. 10 (a), the mold used in the method of the present invention has a space portion having the same shape as the product shape, and has a built-in punch that can move forward and backward toward this space portion.

  In this example, punches are provided on the upper and lower molds. However, depending on the part where the flange is provided or the shape of the flange, the crushing punch may be provided on only one side of the upper and lower molds.

  The shape of the punch for forming the flange is not particularly limited, and may be matched with the shape of the target flange.

  As a processing step, an upper mold incorporated in a hydraulic bulge processing apparatus (not shown) is raised, and a metal base tube is set in the hole mold of the lower mold, and the upper mold as shown in FIG. 10 (a). Lower the mold and contact the lower mold.

  Next, as shown in FIG. 10 (b), pressure is applied to the liquid introduced into the mold tube, and the bulge processing is performed on the flange formation scheduled portion while performing the hydraulic bulge processing to the product shape. In this case, it may be stopped halfway without completely expanding to the product shape.

  Thereafter, the punches built in the upper and lower molds are advanced, and the bulging portion is crushed and formed into a flange as shown in FIG. 10 (c).

  Here, there are cases where the flange can be formed by advancing the punch while maintaining the internal pressure, but if the crushing process is performed by advancing the punch while the internal pressure is high, material breakage tends to occur. Moreover, a great force is required for the crushing process. Therefore, it is desirable to perform the crushing process after reducing the internal pressure.

  Finally, as shown in FIG. 10 (d), the internal pressure is increased while the flange formation planned part is held by a punch, and the parts other than the flange formation planned part formed in the second step are re-molded to obtain the final product. Finish in shape.

  In addition, it is necessary to load a load of such a size that the bulging portion is crushed and the punch is not lifted by the hydraulic pressure in the step of FIG. 10 (d).

  Next, although it is the shape of a flange, what is necessary is just to make it the shape which is easy to couple | bond with the other components to couple | bond.

  FIG. 11 is a view showing the shape of the flange. FIG. 11 (a) is a perspective view of a processed part in which the upper and lower punches are crushed and a flange is provided in the middle of the side, and FIG. 11 (b) is one side. FIG. 6 is a perspective view of a processed part that is crushed only with a punch and provided with a flange that is flush with the lower surface.

  In the case of FIGS. 11 (a) and 11 (b), since the circumference of the cross section including the flange of the bulge processed part is the same from the first bulge process to the final finish bulge process, cracks may occur during the process. Wrinkles do not occur and can be easily molded.

  FIG. 11 (c) is a perspective view of a machined part in which a punch is pushed into the center of the bulging portion and the upper and lower walls are brought into close contact with each other to form a flange. When the flange is provided in the center of the width, the circumferential length of the shape with the flange is increased by twice the height h1 of the cross section than the circumferential length of the shape without the flange. Therefore, it is desirable to reduce the height h1 of the cross section.

(Example 1)
FIG. 12 is a view showing a hole shape of a mold used for forming a part having a flange protruding outside the bulging portion formed by bulging, and FIG. 12 (a) is a plan view of the hole mold. Fig. 12 (b) is a front view, and Fig. 12 (c) is a side view. In the figure, 21 is a space portion having the same shape as the external shape of the product, and 22 is a space portion for expanding the flange forming scheduled portion of the metal base tube.

  The die size of the mold was H: 50 mm, W1: 40 mm, W: 80 mm, R: 8 mm, L: 80 mm.

  Two types of punches having a cross section of 80 mm × 40 mm and 60 mm × 40 mm were used. Also, a carbon steel pipe STKM11A for mechanical structure having an outer diameter of 76.3 mm, a wall thickness of 2.0 mm, and a length of 700 mm is used as the raw pipe, and a flange having the shape shown in FIGS. 8A and 8B is formed. did.

  FIG. 14 is an operation pattern of internal pressure, shaft pushing and punching during hydraulic bulge processing. Only at the time of the first hydraulic bulging, axial pressing force was applied from both ends of the metal base tube, and bulging was performed by bulging with hydraulic pressure. Then, the internal pressure was released, the punch was advanced, and the flange was molded. Finally, with the punch moved forward, only the internal pressure was raised to the same level as in the first hydraulic bulging, and finished to the final shape.

  The length of the bulging portion {L1 in FIG. 6 (b)} corresponding to the flange before crushing with a punch was 15 mm, but the length after crushing with a punch and flattening {Fig. L2} of 6 (c) was 27 mm. The flange length {L3 in FIG. 6D) in the final shape after the second hydraulic bulge processing was 26 mm.

  Both of the two types of punches have no shape defects or cracks. When the punch width is 80 mm, the flange has a flat shape as shown in FIG. 8 (a). When the punch width is 60mm, as shown in FIG. 8 (b). A flange with ribs on both sides of the flange could be formed.

  As a result of investigating the rigidity by applying a load to the flange portion, the flange with the rib showed about 50 times the rigidity of the case without the rib.

(Example 2)
FIG. 13 is a view showing a hole shape of a mold used for forming a part having a flange inside a bulge portion formed by bulging, and FIG. 13 (a) is a plan view of the hole mold. 13 (b) is a front view, and FIG. 13 (c) is a side view. FIG. 13D is an end face shape diagram of the punch. The punch is located at the dotted line in FIG.

  The hole size of the mold was H: 50 mm, W: 80 mm, R: 8 mm, the punch shape was h: 30, w30, and the corner R at the corners of the side and end faces was 3 mm.

  A carbon steel pipe STKM11A for mechanical structure having an outer diameter of 76.3 mm, a wall thickness of 2.0 mm, and a length of 700 mm was used as the raw pipe, and a flange having the shape shown in FIGS. 11A and 11B was formed.

  The internal pressure, shaft pushing, and punch operation patterns during hydraulic bulging were as shown in FIG.

  Only at the time of the first hydraulic bulging, the shaft was pressed from both ends of the metal base tube and expanded by hydraulic pressure to bulge, then the internal pressure was released and the punch was advanced to form a flange. Finally, with the punch moved forward, only the internal pressure was raised to the same level as in the first hydraulic bulge processing to finish the final shape.

  As a result, a bulge-formed part having a flange in the bulge-processed portion was obtained without any defective shape or cracking during processing.

  According to the present invention, flanges of any shape and size that can be spot welded and bolted to other parts can be formed during the process of hydraulic bulging and are required at any location of hydraulic bulging parts. Hydraulic bulge parts with minimum flanges can be obtained.

It is a perspective view which shows the example of a coupling | bonding of the conventional board press component and other components. It is a perspective view which shows the example of a coupling | bonding of the conventional hydraulic bulge processing component and other components. It is a perspective view which shows the other example of the coupling | bonding of the conventional hydraulic bulge processing component and other components. It is a figure for demonstrating the flange forming method by the hydraulic pressure of the conventional hydraulic bulge processing component. It is a perspective view for demonstrating the problem of the flange forming method of the conventional hydraulic bulge processing components. It is sectional drawing for demonstrating the shaping | molding method of components which have the flange protruded outside the bulging part. It is a perspective view which shows the example of the shape of the state which expanded the flange shaping | molding scheduled part of the metal element pipe partially. It is a perspective view of the example of hydraulic bulge processing parts of the present invention. It is a figure which shows the example of a flange provided with the rib. It is a figure for demonstrating the method of forming the hydraulic bulge processing component provided with the flange inside the bulging part. It is a figure which shows the shape of the flange provided in the bulge process part. It is a figure which shows the hole shape of the metal mold | die used in the Example. It is a figure which shows the hole shape of the metal mold | die used in order to shape | mold a flange in a bulge process part. It is explanatory drawing of the internal pressure at the time of a bulge processing, and a shaft pushing pattern

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a, 1b Member 2 Flange 3 Other parts 4 Spot welding part 7a, 7b Arc welding part 10 Metal elementary pipe 11 Lower mold 12 Upper mold 21 Space part for product shape shaping 22 Space part for bulging part molding 23 Punch 25 Bulge 31 rib

Claims (2)

A hydraulic bulging part having a flange for joining other parts protruding outside from the bulging part formed by hydraulic bulging, and the flange constitutes the bulging part A flanged hydraulic bulge processing part characterized in that a flange is formed by being crushed and then crushed and partly having ribs at one end or both ends of the flange. 2. The flanged hydraulic bulge part according to claim 1, wherein the rib is for improving the strength and rigidity of the flange.

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