JP4807550B2 - Liquid pressure forming method and liquid pressure forming apparatus - Google Patents

Description

  The present invention relates to a hydraulic forming method used for injecting a working fluid into a cylindrical member having a substantially circular cross section and forming the product into a product shape having a curved portion while applying hydraulic pressure to the cylindrical member. And a hydraulic forming apparatus.

  As a hydraulic forming apparatus for manufacturing a product having a curved portion from a cylindrical member having a substantially circular cross section by hydraulic molding, an upper die and a lower die having a shape cavity of a product having a curved portion, and these Some of them are equipped with a hydraulic pressure application mechanism that injects the working fluid into the cylindrical member introduced between the upper and lower molds and applies hydraulic pressure to the cylindrical member. In the case of manufacturing a product having a cylindrical member, it is necessary to bend the cylindrical member having a substantially circular cross section so as to match the shape cavity before introducing the cylindrical member between the upper die and the lower die. .

When bending the cylindrical member into a predetermined shape before hydraulic forming, a so-called processing method of bending the cylindrical member by sandwiching the cylindrical member between the rotary die and the clamp die and rotating the rotary die while holding the presser die, so-called When the rotary drawing method is used, the productivity is low and the cost is high due to the large number of bending processes. Therefore, conventionally, a cylinder that is substantially linear between the upper die and the lower die of the hydraulic forming device. A method is employed in which a cylindrical member is bent and the cylindrical member is bent at the stage of clamping the upper die and the lower die.
JP 2001-205350 A

  However, in the conventional hydraulic forming method described above, bending by the rotational pulling bending method is omitted, and the cylindrical member is bent using the upper die and the lower die having the shape cavity of the hydraulic forming device. Therefore, it cannot be bent while maintaining the substantially circular cross section of the cylindrical member.

  When hydraulic forming is performed on a cylindrical member whose cross section is not maintained in a substantially circular shape, wrinkles may occur in the curved portion of the manufactured product. For example, when a large load is applied to such a product, it cannot be said that there is no risk that the portion of the heel will be bent and the strength of the product will be significantly reduced. It has a problem that it cannot be used for manufacturing a member to be manufactured, and it has been a conventional problem to solve this problem.

  The present invention has been made paying attention to the above-described conventional problems, and in the case of manufacturing a product having a curved portion, it is possible to prevent wrinkles from being generated in the curved portion. It is an object of the present invention to provide a hydraulic molding method and a hydraulic molding apparatus capable of producing a product with almost no fear of a decrease in strength, that is, a member that requires a high strength such as a vehicle body structural member.

  In the hydraulic forming method according to the present invention, a cylindrical member is inserted between an upper mold and a lower mold in which a product-shaped cavity having two curved portions is formed, and the upper mold and the lower mold are clamped. It is intended to inject a working fluid into the cylindrical member and form it into a predetermined shape while applying hydraulic pressure to the cylindrical member, and the two curves of the product in the substantially linear cylindrical member The inner surface formed between the two positions corresponding to the portion and formed with the concave portion of the cylindrical member to match the shape cavity following the formation of the concave portion on the inner surface side of the fixed portion that is not displaced during bending. After the side is bent, hydraulic pressure is applied to the tubular member.

  The hydroforming apparatus according to the present invention includes an upper die and a lower die each having a shape cavity of a product having two curved portions, and a processing liquid is injected into the inside of a cylindrical member introduced between the upper die and the lower die. A recess forming mold that is provided with a hydraulic pressure applying mechanism that injects and applies hydraulic pressure to the cylindrical member, and is arranged in the lower mold so that it can protrude from the lower mold toward the upper mold, and the concave forming mold A recess formed between the two positions corresponding to the two curved portions of the product in the substantially linear member, and forming a recess on the inner surface side of the fixed portion that is not displaced during bending. It is characterized in that a forming mechanism and a bending mechanism that performs bending on the inner surface side where a concave portion of a cylindrical member having a substantially circular cross section is formed to match the shape cavity are provided.

  In the present invention, for example, in the stage of clamping the upper die and the lower die, when bending is performed on the inner surface side in which the concave portion of the substantially linear member is formed so as to match the shape cavity, The remainder of the material is generated inside the bent part of the cylindrical member, but between the two positions corresponding to the two curved parts of the product in the substantially linear cylindrical member, the fixed part that is not displaced during bending Since the concave portion is formed on the inner surface side, the remainder of the material actively concentrates on the concave portion and becomes bent, and the depth advances, while it corresponds to the curved portion of the product of the cylindrical member. There is no surplus of material at the location.

  In this state, when the machining liquid is injected into the cylindrical member and molded into a predetermined shape while applying hydraulic pressure to the cylindrical member, the concave portion expands to the shape cavity due to the hydraulic pressure. A product with no defects will be obtained.

  According to the present invention, since it is configured as described above, when manufacturing a product having a curved portion, it is possible to prevent wrinkles from occurring in the curved portion, and therefore, the strength of the vehicle body structural member is hardly reduced. This makes it possible to produce a product that is suitable for the above-mentioned purpose.

  In the hydroforming method according to the present invention, after forming the concave portion in a portion other than the position corresponding to the curved portion of the product of the substantially linear tubular member, the substantially linear tubular member is When the upper and lower molds are inserted into the mold and the upper mold and the lower mold are clamped, the cylindrical member is bent to match the shape cavity, and the upper mold and the lower mold are in a predetermined clamping state. After that, it is possible to adopt a configuration in which a processing liquid is injected into the cylindrical member and molded into a predetermined shape while applying hydraulic pressure to the cylindrical member. Compared with the case where the cylindrical member is bent using, the productivity can be improved and the cost can be reduced to the extent that the bending process can be omitted.

  Further, in the hydraulic forming method of the present invention, a cylindrical member having a substantially linear shape is inserted between the upper mold and the lower mold, and a concave portion is formed in the cylindrical member at the stage of clamping the upper mold and the lower mold. Subsequently, the cylindrical member is bent to match the shape cavity, and after the upper mold and the lower mold are in a predetermined clamping state, the machining liquid is injected into the cylindrical member, In this case, the cylindrical member may be formed into a predetermined shape while applying hydraulic pressure. In this case, the cylindrical member is only once set between the upper die and the lower die, and the concave portion is formed and bent in the cylindrical member. Therefore, the productivity can be further improved and the cost can be significantly reduced by the amount that the movement of the cylindrical member between the processes can be eliminated or the bending process can be omitted. .

  Further, in the hydroforming method of the present invention, the concave portion is formed on the portion corresponding to the straight portion other than the curved portion of the product in the tubular member and on the fixed portion side where the tubular member is not displaced during bending from the curved end of the curved portion. In this case, the processing liquid is injected into the cylindrical member, and in the step of forming the predetermined shape while applying the hydraulic pressure to the cylindrical member, the concave portion is formed by the hydraulic pressure. Therefore, the occurrence of molding defects due to insufficient swelling of the recesses can be more reliably avoided.

  Furthermore, in the hydroforming method of the present invention, when the distance from the bending end of the bending portion to the approximate center of the concave portion is m and the curvature radius of the bending portion is R, 0.2R ≦ m ≦ 0.5R is satisfied. The depth of the concave portion is set so as to satisfy 0.10D ≦ H ≦ 0.45D, where H is the configuration in which the concave portion is formed at the position, the depth of the concave portion is H, and the diameter in the substantially circular cross section of the cylindrical member is D In this case, the position and depth of the recess can be defined.

  On the other hand, in the hydraulic forming apparatus of the present invention, the upper mold and the lower mold may also serve as a bending mechanism, and when this configuration is adopted, compared to the case of bending the tubular member by so-called rotational pulling, The productivity can be improved and the cost can be reduced as much as the bending process can be omitted.

  Further, in the hydroforming apparatus of the present invention, the recess forming mechanism is configured to have a recess forming mold disposed in the lower mold, or the recess forming mechanism is disposed in the lower mold and the upper mold is moved from the lower mold to the upper mold. It may be configured to include a recess forming mold that can be projected and retracted toward the surface and a driving means for the recess forming mold. In this case, a device for forming the recess in the cylindrical member is formed by hydraulic molding. There is no need to install it separately from the apparatus. As a result, it is possible to contribute to space saving, and it is possible to automate the production of a product having a curved portion.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to a following example.

  1-5 has shown the point which manufactures the product which has a curved part from a cylindrical member with the hydraulic forming method by one Example of this invention.

  In this hydraulic forming method, as shown in FIG. 1 (a), first, a linear tubular member W having a substantially circular cross section is placed on the device base 2 of the recess forming device 1, and then shown in FIG. 1 (b). As shown, the concave mold 3 is lowered in this state to form the concave portion Wd in the cylindrical member W, thereby obtaining the concave cylindrical member W shown in FIG. Note that the position where the concave portion Wd is formed is a portion corresponding to the inner side surface of the curved portion of the product.

  Next, as shown in FIG. 3, the above-described tubular member W with a concave portion that remains linear is set in the member holding portion 13 that can be raised and lowered of the hydraulic forming apparatus 10. The hydraulic forming apparatus 10 used here includes an upper mold 11 and a lower mold 12 having product-shaped cavities 11a and 12a having curved portions, and an upper mold 11 and a lower mold 12 held by the member holding section 13. A hydraulic pressure imparting mechanism 20 is provided for injecting a machining fluid into a cylindrical member W with a concave portion inserted therebetween and applying a hydraulic pressure.

  After the cylindrical member W with a recess is inserted between the upper die 11 and the lower die 12 in this way, the upper die 11 is lowered and the upper die 11 and the lower die 12 are clamped as shown in FIG. Then, the cylindrical member W in which the concave portion Wd is formed is gradually bent.

  At this time, both ends of the cylindrical member W descending together with the member holding portion 13 are on the bending action point side, the center of the cylindrical member W is on the fixed portion side that is not displaced by bending, and the concave portion Wd is the cylindrical member. It is a part corresponding to a straight line part other than the curved part of the W product and is located on the fixed part side from the curved end of the curved part.

  Then, when the upper die 11 is further lowered and the bending process is advanced, the remainder of the material caused by the bending process is generated inside the bent part of the cylindrical member W with the concave part. Since the concave portion Wd is formed at a portion other than the position corresponding to the above, the material surplus actively concentrates on the concave portion Wd and becomes bent, and the depth advances. There is no material surplus at the position corresponding to the curved portion of the product.

  Next, as shown in FIG. 5, in the state where the upper mold 11 and the lower mold 12 have been clamped, the axial push cylinder 21 of the hydraulic pressure applying mechanism 20 is advanced, and the punch mold 22 attached to the tip thereof is used. After sealing both ends of the cylindrical member W with a recess located between the upper mold 11 and the lower mold 12, the processing liquid supplied from a hydraulic pressure generator (not shown) is passed through the high pressure hose 23 and the punch mold 22. By injecting into the inside of the cylindrical member W with a recess and gradually increasing the hydraulic pressure, the cylindrical member W having a substantially circular cross section is shaped into the cavities 11a and 12a formed in the upper die 11 and the lower die 12. Mold.

  At this time, the concave portion Wd swells to the shape cavities 11a and 12a due to the hydraulic pressure, so that a product free from molding defects such as wrinkles and dents can be obtained. Since the concave portion Wd is disposed at the portion corresponding to the straight portion and on the fixed portion side from the bending end of the bending portion, the concave portion Wd easily expands to the shape cavities 11a and 12a by the hydraulic pressure, and therefore the expansion of the concave portion Wd is insufficient. Occurrence of molding defects due to is more reliably avoided.

  As described above, in this embodiment, in order to increase productivity, the upper mold 11 and the lower mold 12 are formed by using the hydraulic forming apparatus 10 in which the bending mechanism is also used. Since the concave portion Wd is formed in W, a product free from molding defects such as wrinkles and dents can be obtained, and therefore, a product suitable for a vehicle body structural member that hardly decreases in strength can be obtained. Become.

  Therefore, as shown in FIG. 3, the distance from the curved end of the curved portion of the product (the curved end of the curved forming portion 12b of the lower mold 12) to the approximate center of the concave portion is m, the radius of curvature of the curved portion is R, When the depth is H and the diameter in the substantially circular cross section of the cylindrical member is D, the distance m from the end of the curve to the recess when the depth H of the recess is 0.2 × D and the wrinkles at the curve When the relationship with the presence or absence of the occurrence of was examined, the results shown in Table 1 were obtained.

  Further, when the relationship between the depth m of the recess when the distance m from the end of the curve to the recess was 0.3 × R and the presence or absence of wrinkles in the bending portion was examined, the results shown in Table 2 were obtained. It was.

  As shown in Table 1, in the portion corresponding to the straight portion other than the curved portion of the product of the cylindrical member W and on the fixed portion side (the central side where the tubular member W is not displaced by the bending process) from the curved end of the curved portion. When the concave portion Wd is disposed at a site satisfying 0.2R ≦ m ≦ 0.5R, no wrinkles occurred in the curved portion. Outside this range, wrinkles occurred in the curved portion.

  On the other hand, as shown in Table 2, when the depth of the concave portion Wd was set so as to satisfy 0.10D ≦ H ≦ 0.45D, wrinkles did not occur in the curved portion. Outside this range, wrinkles occurred in the curved portion.

  6 to 10 show another embodiment of the hydraulic forming method of the present invention. The difference between the hydraulic forming method of this embodiment and the hydraulic forming method of the previous embodiment is that it is cylindrical. Use of a hydroforming apparatus 10A provided with a recess forming mechanism 30 for forming the recess Wd in the member W and a bending mechanism for bending the cylindrical member W having a substantially circular cross section to match the shape cavities 11a and 12a. Other configurations are the same as those of the previous embodiment.

  In this case, the upper mold 11 and the lower mold 12 also serve as a bending mechanism. On the other hand, the recess forming mechanism 30 is disposed in the lower mold 12 so that the recess can be protruded from the lower mold 12 toward the upper mold 11. A mold 31 and a recess forming cylinder 32 as a driving means for the recess forming mold 31 are provided.

  In this hydraulic forming method, as shown in FIG. 6, first, a linear cylindrical member W having a substantially circular cross section is inserted between the upper mold 11 and the lower mold 12 of the hydraulic forming apparatus 10A to move up and down. After setting on the possible member holding portion 13, the upper die 11 is lowered as shown in FIG. 7.

  At this time, since the recess forming mold 31 of the recess forming mechanism 30 protrudes from the lower mold 12 toward the upper mold 11, the recess Wd is formed in the cylindrical member W.

  Next, as shown in FIG. 8, the upper die 11 is lowered and the upper die 11 and the lower die 12 are clamped to gradually curve the cylindrical member W in which the concave portion Wd is formed, and the concave portion forming mechanism 30. The recessed part forming cylinder 32 is actuated so that the recessed part forming mold 31 protruding from the lower mold 12 toward the upper mold 11 is buried in the lower mold 12.

  At this time, both ends of the cylindrical member W descending together with the member holding portion 13 are on the bending action point side, the center of the cylindrical member W is on the fixed portion side that is not displaced by bending, and the concave portion Wd is the cylindrical member. It is a part corresponding to a straight line part other than the curved part of the W product and is located on the fixed part side from the curved end of the curved part.

  Then, when the upper die 11 is further lowered and the bending process is advanced, the remainder of the material caused by the bending process is generated inside the bent part of the cylindrical member W with the concave part. Since the concave portion Wd is formed at a portion other than the position corresponding to the above, the material surplus actively concentrates on the concave portion Wd and becomes bent, and the depth advances. There is no material surplus at the position corresponding to the curved portion of the product.

  Next, as shown in FIG. 9, in a state where the upper mold 11 and the lower mold 12 have been clamped, the axial push cylinder 21 of the hydraulic pressure applying mechanism 20 is advanced, and the punch mold 22 attached to the tip thereof is used. After sealing both ends of the cylindrical member W with a recess located between the upper mold 11 and the lower mold 12, the processing liquid supplied from a hydraulic pressure generator (not shown) is passed through the high pressure hose 23 and the punch mold 22. By injecting into the inside of the cylindrical member W with a recess and gradually increasing the hydraulic pressure, the cylindrical member W having a substantially circular cross section is shaped into the cavities 11a and 12a formed in the upper die 11 and the lower die 12. Mold.

  At this time, as shown in FIG. 10, the concave portion Wd expands to the shape cavities 11a and 12a due to the hydraulic pressure, so that a product free from molding defects such as wrinkles and dents can be obtained. Since the concave portion Wd is disposed at a portion corresponding to a straight portion other than the curved portion of the product of W and on the fixed portion side from the curved end of the curved portion, the concave portion Wd easily expands to the shape cavities 11a and 12a by hydraulic pressure. Therefore, the occurrence of molding defects due to insufficient swelling of the recesses Wd is more reliably avoided, and therefore, a product suitable for a vehicle body structural member that hardly deteriorates in strength is obtained.

  In the above-described hydraulic forming method, a substantially linear tubular member W is inserted between the upper mold 11 and the lower mold 12 of the hydraulic forming apparatus 10A, and the upper mold 11 and the lower mold 12 are clamped. Then, after forming the recess Wd in the cylindrical member W, the cylindrical member W is bent to match the shape cavities 11a and 12a. It is only necessary to set it once between twelve times, and as a result, it is possible to eliminate the movement of the cylindrical member W between processes and to omit the bending process, thereby further improving productivity and cost. A significant reduction will be achieved.

  Further, in the above-described embodiment, the recess forming die 31 that is arranged on the lower die 12 and can protrude from the lower die 12 toward the upper die 11, and the recess forming cylinder 32 as a driving means of the recess forming die 31. Therefore, it is not necessary to install a device for forming the concave portion Wd in the cylindrical member W separately from the hydraulic molding device 10A. It is possible to contribute to space and to automate the production of a product having a curved portion.

  In the above-described embodiment, the case where the hydraulic forming is performed using the hydraulic forming apparatus 10A provided with the two sets of the recess forming mechanism 30 is shown. However, as another configuration, for example, as shown in FIG. You may perform hydraulic forming using the hydraulic forming apparatus 10B provided with the recessed part formation mechanism 30B formed by integrating the recessed part formation mechanism 30 of a group.

It is operation | movement explanatory drawing (a) and (b) at the time of forming a recessed part in the cylindrical member which shows one Example of the hydraulic forming method of this invention. (Example 1) It is side surface explanatory drawing of the cylindrical member in which the recessed part was formed. It is a section explanatory view in the state where the cylindrical member shown in Drawing 2 was set to the hydraulic forming device. FIG. 4 is a cross-sectional explanatory diagram of a mold clamping state of the hydraulic forming apparatus illustrated in FIG. 3. FIG. 4 is an explanatory cross-sectional view of the hydraulic forming apparatus shown in FIG. It is sectional explanatory drawing of the state which set the cylindrical member to the hydraulic forming apparatus used with the other Example of the hydraulic forming method of this invention. (Example 2) FIG. 7 is an explanatory cross-sectional view of the hydraulic forming apparatus shown in FIG. 6 when a recess is formed. FIG. 7 is a cross-sectional explanatory diagram of a mold clamping state of the hydraulic forming apparatus illustrated in FIG. 6. FIG. 7 is an explanatory cross-sectional view of the hydraulic forming apparatus shown in FIG. FIG. 7 is a cross-sectional explanatory diagram of the hydraulic forming apparatus shown in FIG. It is sectional explanatory drawing of the hydraulic forming apparatus used with the further another Example of the hydraulic forming method of this invention. (Example 3)

Explanation of symbols

10, 10A, 10B Hydraulic forming equipment 11 Upper mold (bending mechanism)
12 Lower mold (bending mechanism)
11a, 12a Product shape cavity 20 Hydraulic pressure applying mechanism 30 Recess formation mechanism 31 Recess formation mold 32 Recess formation cylinder (drive means)
W Cylindrical member Wd Concave m Distance from the end of the curved portion to the approximate center of the concave portion R Radius of curvature of the curved portion H Depth of the concave portion D Diameter of the cylindrical member in a substantially circular cross section

Claims (8)

A cylindrical member is inserted between an upper die and a lower die in which a product shape cavity having two curved portions is formed, and the upper die and the lower die are clamped and a processing liquid is injected into the cylindrical member. Then, in the hydraulic forming method of forming into a predetermined shape while applying hydraulic pressure to the cylindrical member,
Following the formation of the concave portion on the inner surface side of the fixed portion which is between the two positions corresponding to the two curved portions of the product in the substantially linear member and which is not displaced during bending, the above-described shape cavity A hydraulic forming method characterized by applying a hydraulic pressure to the cylindrical member after bending the inner side surface on which the concave portion of the cylindrical member is formed in order to match the above .   Following the formation of the recess, the cylindrical member having a substantially linear shape is inserted between the upper mold and the lower mold, and the upper mold and the lower mold are clamped to match the shape cavity. After the cylindrical member is bent and the upper mold and the lower mold are in a predetermined clamping state, a processing liquid is injected into the cylindrical member, and a predetermined shape is applied while applying hydraulic pressure to the cylindrical member. The hydraulic forming method according to claim 1, wherein the forming is performed.   In order to fit the shape cavity, the cylindrical member having a substantially straight shape is inserted between the upper die and the lower die, and the upper die and the lower die are clamped. After the cylindrical member is bent and the upper mold and the lower mold are in a predetermined clamping state, a processing liquid is injected into the cylindrical member, and a predetermined shape is applied while applying hydraulic pressure to the cylindrical member. The hydraulic forming method according to claim 1, wherein the forming is performed.   The concave portion is formed at a position satisfying 0.2R ≦ m ≦ 0.5R, where m is the distance from the bending end of the curved portion to the approximate center of the concave portion and R is the radius of curvature of the curved portion. The hydraulic forming method according to any one of the items.   5. The depth of the recess is set to satisfy 0.10D ≦ H ≦ 0.45D, where H is the depth of the recess and D is the diameter of the cylindrical member in the substantially circular cross section. The hydraulic forming method according to one item. An upper mold and a lower mold having a shape cavity of a product having two curved portions, and a processing liquid is injected into the cylindrical member put between the upper mold and the lower mold, so that the hydraulic pressure is applied to the cylindrical member. In a hydraulic forming apparatus equipped with a hydraulic pressure application mechanism to be applied,
Two concave portions of the product in the cylindrical member that is arranged in the lower die and includes a concave portion forming die that can be projected and lowered from the lower die toward the upper die, and a driving means for the concave portion forming die. And a concave portion forming mechanism for forming a concave portion on the inner surface side of the fixed portion that is not displaced during bending, and a cylindrical member having a substantially circular cross section to match the shape cavity. A hydraulic forming apparatus comprising a bending mechanism for bending the inner side surface.   The hydraulic forming apparatus according to claim 6, wherein the upper mold and the lower mold also serve as a bending mechanism.   The hydraulic forming apparatus according to claim 6 or 7, wherein the recess forming mechanism includes a recess forming mold disposed in the lower mold.

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