JP2004337898A - Hydraulic forming method and hydraulic forming device for tubular member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic forming method for a tubular member in which strains can be introduced to a tube-expanding part by regulating the inflow of a material from a tube-non-expanding part to the tube-expanding part when the tubular member is hydraulically formed. <P>SOLUTION: When the forming is executed by applying hydraulic pressure on the inside of the tubular member W, a prescribed length from both ends of the tubular member W is constrained in a state that the tube is not expanded by the hydraulic pressure. Both of end parts are made the tube-non-expanding parts A. The intermediate part of the tubular member W is formed into a prescribed shape by applying the hydraulic pressure on the tubular member W while regulating the inflow of the material to the longitudinal direction of the tube-non-expanding parts A. As a result, the strains can be introduced to the formed tube-expanding part B. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to, for example, a hydraulic forming method and a hydraulic forming apparatus for a tubular member used for manufacturing a tubular member used for a structural member of an automobile or the like.
[0002]
[Prior art]
As a conventional hydraulic forming method, for example, a hydroforming method as shown in FIG. 7 is known. In this hydroforming method, as shown in FIG. 7A, the tubular member 110 is set on the lower die 102, and the lower die 102 is pressed against the lowered upper die 101, followed by the upper die guide portion 101a. The axial pressing tools 103 and 104 are advanced toward both ends of the tubular member 110 sandwiched between the lower guide 102a and the lower die guide portion 102a, and the respective leading portions 103a and 104a are pressed into the tubular member 110.
[0003]
Then, the working fluid 105 is filled into the tubular member 110 from the flow paths 103b, 104b of the axle pushing tools 103, 104, and the axle pushing tools 103, 104 are advanced while increasing the pressure of the working fluid 105 to form a tubular member. By applying an axial compressive force to the member 110, as shown in FIG. 7B, the intermediate portion of the tubular member 110 is expanded into the upper and lower space 106 while the length of the tubular member 110 is reduced. It is formed into a predetermined shape (see Patent Document 1).
[0004]
FIG. 8 is a diagram showing a hydraulic forming method for expanding a pipe outside the mold. That is, in this hydraulic forming method, as shown in FIG. 8A, the constraining rings 201 are attached to both ends of the tubular member 210, and are set in a pressing device (not shown). The nozzle 202 is advanced to insert the nozzle tip 202 a into the tubular member 210. Next, as shown in FIG. 8B, the processing liquid 103 is filled into the tubular member 210 from the flow path 202b of the nozzle 202, and the pressure of the processing liquid 5 is further increased so that the intermediate portion of the tubular member 210 is removed. After the expansion, the expanded portion of the tubular member 210 is formed into a predetermined shape by a mold attached to a ram of a press machine.
[0005]
[Patent Document 1]
JP 2001-321844 A
[Problems to be solved by the invention]
However, in the conventional hydraulic forming method as described above, in the hydroforming method, an axial compression force is applied to the tubular member being formed by the axial pressing tool, so as to reduce the length of the tubular member. Material flows from the non-expanded section at both ends sandwiched between the upper and lower dies to the middle expanded section, reducing the amount of distortion introduced into the expanded section and changing the shape of the expanded section to expand the pipe between the upper and lower dies. In such a case, the mold had to be replaced, which resulted in an increase in cost and an increase in man-hours accompanying the mold replacement.
[0007]
Further, in the hydraulic forming method in which the tube is expanded outside the mold, no axial compressive force is applied to the tubular member being formed, but the material is restricted from flowing in the longitudinal direction of the tubular member during tube expansion. The force is only the force of the hydraulic pressure pressing the tubular member against the restraining ring, and is insufficient as a force for restricting the material inflow, and it has been difficult to control the longitudinal reduction of the tubular member.
[0008]
As described above, in the conventional hydroforming method, when the tubular member is hydroformed, the material flows from the non-expanded portion of the tubular member to the expanded portion, and the length of the tubular member is reduced. However, there is a problem that it is difficult to introduce a distortion into the light.
[0009]
[Object of the invention]
The present invention has been made in view of the above-described conventional problems, and restricts the flow of material from a non-expanded portion to an expanded portion during hydraulic forming of a tubular member, and introduces strain into the expanded portion. It is an object of the present invention to provide a method and apparatus for hydroforming a tubular member.
[0010]
[Means for Solving the Problems]
The method for hydraulic forming of a tubular member of the present invention is characterized in that, when forming is performed by applying a hydraulic pressure to the inner surface of the tubular member, a predetermined length range from both ends of the tubular member is restrained so as not to be expanded by hydraulic pressure. It is characterized in that both end portions are non-expanded portions, and a fluid pressure is applied to the tubular member while regulating the material inflow in the longitudinal direction of the non-expanded portion to form an intermediate portion of the tubular member into a predetermined shape.
[0011]
Further, the hydraulic forming apparatus for a tubular member of the present invention is a hydraulic forming apparatus for performing forming by applying a hydraulic pressure to an inner surface of the tubular member, wherein a predetermined length range from both ends of the tubular member is set as a non-expandable portion. It is characterized in that it is provided with a restricting means for restricting the tube from being expanded by pressure and restricting the inflow of material in the longitudinal direction of the non-expanded portion when a hydraulic pressure is applied to the tubular member.
[0012]
Further, the tubular member of the present invention is characterized by being manufactured by the above-mentioned hydraulic forming method, and the shock absorbing member of the present invention is made of the above tubular member, and uses the non-expanded portion as a shock absorbing region. It is characterized by.
[0013]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the hydraulic forming method of the tubular member of the present invention, when performing the forming by applying the hydraulic pressure to the inner surface of the tubular member, the material flows from the non-expanded portion to the expanded portion when the tubular member is hydroformed. Therefore, it is possible to provide a tubular member in which strain is introduced into the expanded portion without reducing the length of the tubular member.
[0014]
ADVANTAGE OF THE INVENTION According to the hydraulic forming apparatus of the tubular member of this invention, in the hydraulic forming apparatus which performs shaping | molding by applying a hydraulic pressure to the inner surface of a tubular member, when a tubular member is hydraulically formed, it changes from a non-expanded part to an expanded part The inflow of the material can be restricted, and a tubular member having a strain introduced into the expanded portion can be provided without reducing the length of the tubular member.
[0015]
According to the tubular member of the present invention, in a tubular member having a non-expanded portion at both end portions and an expanded portion at an intermediate portion, strain can be introduced into the expanded portion. According to the shock absorbing member, a sufficient shock absorbing function can be obtained by using the non-expanded portion as a shock absorbing region.
[0016]
【Example】
Hereinafter, based on the drawings, embodiments of the hydraulic forming method, the hydraulic forming apparatus, the tubular member and the shock absorbing member of the present invention will be described, but the detailed configuration thereof is not limited to the following embodiments. Absent.
[0017]
(Example 1)
The hydraulic forming apparatus shown in FIG. 1A performs forming by applying a hydraulic pressure to the inner surface of the tubular member W, and extends a predetermined length range from both ends of the tubular member W to the non-expandable portions A, As A, there is provided a restricting means for restricting the pipe from being expanded by hydraulic pressure and for restricting the inflow of material in the longitudinal direction of the non-expanded portions A, when hydraulic pressure is applied to the tubular member W. The tubular member W is a steel pipe having a circular cross section having strain aging properties.
[0018]
The restricting means in this embodiment includes a pair of restraining rings 1 and 1 fitted to the outside of the tubular member W, and a pair of supply nozzles 3 and 3 having a working fluid supply path 2 into the tubular member W. . The constraining ring 1 is fitted to a portion corresponding to each non-expanded portion A of the tubular member W with each end T of the tubular member W to be expanded in a tapered shape protruding later. On the other hand, the supply nozzle 3 is disposed opposite to both ends of the tubular member W, and can be advanced and retracted with respect to the tubular member W by a driving device (not shown). The source is connected.
[0019]
The constraining ring 1 and the supply nozzle 3 are provided with pressure forming portions 4 and 5 that face each other and expand at least the end portion T of the tubular member W into a tapered shape. The pressure forming part 4 of the restraining ring 1 is a concave tapered surface formed on the end face of the ring 1. On the other hand, the pressure forming part 5 of the supply nozzle 3 is a convex tapered surface formed around the nozzle tip 3a.
[0020]
In the above-mentioned hydraulic forming apparatus, each of the restraining rings 1 is fitted to both end portions of the tubular member W, and each of the restraining rings 1 is set in a ring receiver of a pressing device (not shown) to position the tubular member W. The nozzle 3 is advanced, and as shown in FIG. 1 (b), as the two supply nozzles 3 advance, between the pressure forming part 5 of each supply nozzle 3 and the pressure forming part 4 of each restraining ring 1, Both ends T of the tubular member W are expanded in a tapered shape. With the expansion, the nozzle tip portions 3a of the supply nozzles 3 are inserted into the inside of both ends of the tubular member W.
[0021]
Next, the hydraulic forming device fills the processing liquid Q into the tubular member W from the processing liquid supply path 2 of each supply nozzle 3 and further increases the pressure of the processing liquid Q by a pressure intensifier (not shown) to form a tubular member. After expanding the intermediate portion (expanded portion B) of the member W, that is, the portion between the pair of restraining rings 1 and 1, the expanded portion B is sectioned by a mold attached to a ram of a press machine as shown in FIG. Form into a square shape.
[0022]
At this time, in the hydraulic forming apparatus and the hydraulic forming method using the same, the non-expanded portions A, which are a predetermined length range from both ends of the tubular member W, are not expanded by the restricting means. More specifically, both ends T of the tubular member W expanded in a tapered shape are formed between the press-formed portion 4 of each restraining ring 1 and the press-formed portion 5 of the supply nozzle 5. While being clamped, the non-expanded portions A, A are constrained by the respective constraining rings 1 so as not to be expanded by hydraulic pressure, and the constraining rings 1 and the press-formed portions 4, 5 of the supply nozzle 3 are expanded. The end T of the tubular member W is sandwiched and metal-sealed.
[0023]
In the hydraulic forming apparatus and the hydraulic forming method, a hydraulic pressure is applied to the tubular member W while restricting the inflow of the material in the longitudinal direction of the non-expanded portions A, A in the above-described state, and the intermediate pressure of the tubular member W is increased. Since the portion (expanded tube portion B) is formed into a predetermined shape, the length of the expanded tube member W is not reduced, and the machining fluid Q does not leak from the end portion T of the tubular member W. Distortion (plane distortion) can be introduced.
[0024]
In the hydraulic forming apparatus and the hydraulic forming method, the end T of the tubular member W is expanded in a tapered shape, and the non-expanded portion A including the end T is restrained by the restricting means. In addition to being able to more reliably regulate the inflow of the material from A to the expanded portion B, at least both ends of the tubular member W are formed by using a means having the machining liquid supply path 2 into the tubular member W, that is, the supply nozzle 3. Since the pipe is expanded in a tapered shape, the expansion of the end portion T and the hydraulic forming by supplying the processing liquid Q can be continuously performed in the same process, thereby improving the workability and productivity. Become.
[0025]
Further, in the hydraulic forming apparatus and the hydraulic forming method, a means having a working liquid supply path into the tubular member W, that is, the supply nozzle 3 is used, and the supply nozzle 3 and the press forming sections 5, 4 of the restraining ring 1 are used. Since the end T of the expanded tubular member W is sandwiched and metal-sealed, there is no need to use a sealing part such as an O-ring, thereby simplifying the structure of the apparatus and reducing the manufacturing cost. It will be.
[0026]
Further, in the hydraulic forming apparatus, if the restricting rings 1 constituting the restricting means are prepared with different lengths in the axial direction, and these are selectively used, the non-expanding section A and the expanding section B can be selectively used. The tubular members W having different lengths can be hydraulically formed, thereby suppressing an increase in cost due to a change in the member shape.
[0027]
Further, in this embodiment, the above-described hydraulic forming is performed on the tubular member W made of a steel pipe having strain aging, and the non-expanded portions A, A at both end portions and the expanded portion B at the intermediate portion are formed as shown in FIG. After forming the tubular member W, the center of the expanded portion B was cut and heat-treated at 170 ° C. for 20 minutes to obtain an impact absorbing member W1 as shown in FIG.
[0028]
Here, the tubular member W obtained by the hydraulic forming method and the hydraulic forming apparatus has a strain introduced into the expanded tube portion B, and the shock absorbing member obtained by cutting the tubular member W and performing heat treatment. W1 has a strength difference between the expanded portion B and the non-expanded portion A, and has a sufficient shock absorbing function with the non-expanded portion A as a shock absorbing region.
[0029]
As described above, the hydraulic forming method and the hydraulic forming apparatus can obtain the integrated shock absorbing member W1 using the non-expanded portion A as a shock absorbing region in a single molding, and can join dissimilar materials. The number of steps can be reduced as compared with the case where a shock absorbing member is manufactured, and it is very advantageous in terms of productivity and manufacturing cost.
[0030]
(Example 2)
The hydraulic forming apparatus shown in FIG. 4 has basically the same configuration as that of the previous embodiment. The same components as those in the previous embodiment are denoted by the same reference numerals, and detailed description is omitted.
[0031]
In this embodiment, a predetermined length range from both ends of the tubular member W is constrained as a non-expanded portion A, A so as not to be expanded by hydraulic pressure, and when hydraulic pressure is applied to the tubular member W, the non-expanded portion A, In the restricting means for restricting the inflow of the material in the longitudinal direction of A, the pressure forming sections 4 and 5 of each of the constraining rings 1 and each of the supply nozzles 3 have a tapered portion Tt and a tapered portion Tt at the end T of the tubular member W. Is formed in such a manner that a flange portion Tf continuous to the large diameter side is formed by pressure.
[0032]
In the hydraulic forming apparatus of this embodiment and the hydraulic forming method using the same apparatus, the same effect as in the previous embodiment can be obtained, and the end T of the tubular member W has a tapered portion Tt. In particular, the contact portion between the end portion T of the tubular member W and the press-formed portion 5 of the supply nozzle 3 is made multi-faceted, and the function of the metal seal is further ensured. It becomes.
[0033]
The tubular member W obtained by the hydraulic forming apparatus and the hydraulic forming method is obtained by cutting the center of the expanded portion B from the state shown in FIG. 5 and performing a heat treatment at 170 ° C. for 20 minutes as shown in FIG. The shock absorbing member W1 has a difference in strength between the expanded portion B and the non-expanded portion A as shown in FIG. In the tubular member W and the shock absorbing member W1, the same effects as in the previous embodiment can be obtained, and the flange portion Tf of the end portion T is used as a joint portion with another member. As a result, the need for joining parts such as brackets is eliminated, which can contribute to a reduction in manufacturing cost.
[0034]
In each of the embodiments described above, the case where a steel pipe having a circular cross section having strain aging is used as the tubular member, but other metal tubes having strain aging may be used as the tubular member, Further, even in the shape of the expanded portion to be hydraulically formed, it can be formed into an appropriate shape other than a square cross section.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view (a) before molding and a cross-sectional view (b) after filling of a working fluid, illustrating a first embodiment of a hydraulic forming apparatus according to the present invention.
FIG. 2 is a side view (a) of the tubular member formed in Example 1, a sectional view taken along line AA in FIG. A, (b), a sectional view taken along line BB in FIG. FIG. 6D is a sectional view taken along line CC of FIG.
3A is a side view of the shock absorbing member manufactured in Example 1, FIG. 3A is a cross-sectional view taken along line AA in FIG. A, and FIG. 3C is a cross-sectional view taken along line BB in FIG.
FIG. 4 is a cross-sectional view (a) before molding and a cross-sectional view (b) after filling with a working fluid, illustrating a hydraulic forming apparatus according to a second embodiment of the present invention.
5A is a side view of the tubular member formed in Example 2, FIG. 5B is a cross-sectional view taken along line AA in FIG. A, FIG. 5C is a cross-sectional view taken along line BB in FIG. FIG. 6D is a sectional view taken along line CC of FIG.
6A is a side view of the shock absorbing member manufactured in Example 2, FIG. 6B is a cross-sectional view taken along the line AA in FIG. A, and FIG. 6C is a cross-sectional view taken along the line BB in FIG.
FIGS. 7A and 7B are a cross-sectional view after a working fluid is filled and a cross-sectional view after expansion of a tube, for explaining a conventional hydraulic forming method.
FIG. 8 is a cross-sectional view (a) before molding and a cross-sectional view (b) after filling with a working fluid, illustrating another example of the conventional hydraulic forming method.
[Explanation of symbols]
Reference Signs List A Non-expanded portion B Expanded portion T End portion of tubular member Tf Flange portion Tt Taper portion W Tubular member W1 Shock absorbing member 1 Restriction ring (restriction means)
2 Processing fluid supply path 3 Supply nozzle (regulation means)
4 5 Press forming part

Claims (12)

When forming by applying a hydraulic pressure to the inner surface of the tubular member, a predetermined length range from both ends of the tubular member is restrained so as not to be expanded by hydraulic pressure, and both end portions are set as a non-expanded portion, and A method for hydraulically molding a tubular member, wherein a hydraulic pressure is applied to the tubular member while regulating the inflow of material in the longitudinal direction to form an intermediate portion of the tubular member into a predetermined shape. 2. The hydraulic forming of a tubular member according to claim 1, wherein after expanding both ends of the tubular member at least in a tapered shape, the non-expanded portion including the expanded portion is restrained and hydraulic pressure is applied to the tubular member. Method. 3. The method according to claim 2, wherein both ends of the tubular member are expanded at least in a tapered shape by using a means having a working fluid supply passage into the tubular member. 4. The method according to claim 3, wherein both ends of the expanded tubular member are metal-sealed using a means having a working fluid supply path into the tubular member. In a hydraulic forming apparatus for performing molding by applying a hydraulic pressure to an inner surface of a tubular member, a predetermined length range from both ends of the tubular member is restricted as a non-expandable portion so as not to be expanded by hydraulic pressure, and the hydraulic A hydraulic forming apparatus for a tubular member, comprising: a restricting means for restricting a material flow in a longitudinal direction of the non-expanded portion when a load is applied. The restricting means includes a restraining ring fitted to the outside of the tubular member, and a supply nozzle having a working fluid supply path into the tubular member, and the restraining ring and the supply nozzle face each other to face the end of the tubular member. The hydraulic forming apparatus for a tubular member according to claim 5, further comprising a pressure forming section for expanding the pipe at least in a tapered shape. The pressure forming part of the constraining ring and the supply nozzle is formed at the end of the tubular member with a shape that presses and forms a taper part and a flange part continuous to a large diameter side of the taper part. Item 7. A tubular member hydraulic forming apparatus according to Item 6. The hydraulic forming apparatus for a tubular member according to claim 6 or 7, wherein the pressure forming part of the constraining ring and the supply nozzle has a function of sandwiching an end of the expanded tubular member and performing metal sealing. . A tubular member produced by the hydraulic forming method according to any one of claims 1 to 4. A shock absorbing member comprising the tubular member according to claim 9, wherein the non-expanded portion is used as a shock absorbing region. The shock absorbing member according to claim 10, wherein the tubular member is made of a metal having strain aging. The shock absorbing member according to claim 11, wherein the tubular member is made of a steel plate having strain aging.

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