JP5530168B2 - Pipe member forming method - Google Patents

Description

  The present invention relates to a method for forming a pipe member composed of a large-diameter portion, a small-diameter portion, a curved portion, and the like such as a steering hanger beam of an automobile.

Steering hanger beam, which is mounted on the body in the width direction of the car and is mounted on the body, requires a higher rigidity on the driver (driver's seat) side than on the assistant (passenger seat) side. Is done. For this reason, there is known a steering hanger beam in which a multi-tube structure portion is integrally formed by press-fitting a metal pipe having substantially the same diameter as the inside of a metal pipe whose outer diameter is restricted. (For example, refer to Patent Document 1).
Further, a steering hanger beam is known in which a reinforcing metal fitting is welded into a portion where rigidity is required.

Japanese Patent No. 3865626

However, in the technique described in Patent Document 1, although a required rigidity can be given to a portion where rigidity is required, a metal pipe having substantially the same diameter is provided inside a metal pipe whose outer diameter is constrained. In order to form a double pipe portion by press fitting while reducing the diameter of the pipe, a large driving force is required. In addition, when mounting reinforcing metal fittings by welding, the necessary rigidity can be ensured, but problems such as increased weight, design restrictions due to designation of the welding direction, an increase in the number of welding steps, an increase in the number of parts and the occurrence of welding thermal distortion, etc. To do.

  The present invention has been made in view of such problems of the prior art, and its object is to reduce the weight, reduce the number of processing steps and parts, and stabilize the bending accuracy. An object of the present invention is to provide a method for forming a member.

In order to solve the above-mentioned problem, the invention according to claim 1 is a pipe member forming method in which a plate thickness reduction rate is maintained at 30% or less and subjected to diameter expansion processing or bending processing to form a desired shape. Hydroforming that expands by compressing the axial direction of the pipe while applying hydraulic pressure to the pipe that has been expanded in this expanding and expanding process. It consists of steps.

The pipe member may be a steering hanger beam that is horizontally mounted in the width direction of the automobile and is used to attach the instrument panel to the body.

The steering hanger beam is composed of a driver side end, a driver side, a center driver side, a center assistant side, an assistant side, and an assistant side end. The driver side end is expanded and expanded by hydroforming after the diameter is expanded. The diameter and the driver side are expanded and expanded, the center driver side is expanded by pressing or bending after pressing and bending, and the center assistant side is expanded or expanded by hydroforming, and the center side is expanded and expanded after pressing or bending. Further, the diameter expansion can be corrected by hydroforming, the assistant side can be processed without machining, and the end on the assistant side can be molded by diameter expansion by hydroforming.

The invention according to claim 4 is a method for forming a pipe member, in which the plate thickness reduction rate of the pipe is maintained at 30% or less and subjected to diameter expansion processing to be molded into a desired shape, and the diameter expansion processing is performed in the pipe. This is a steering hanger beam that consists of a hydroforming process in which the pipe axial direction is compressed while applying hydraulic pressure to expand the diameter, and the pipe member is mounted horizontally on the width direction of the automobile to attach the instrument panel to the body. .

According to the present invention, since the pipe member can be expanded in diameter while maintaining the plate member thickness reduction rate at 30% or less, the required rigidity can be ensured without increasing the weight and the number of parts. In addition, after the expansion and expansion of the pipe using the expansion punch and bending, the entire pipe member is subjected to processing such as internal pressure expansion, correction molding and correction expansion with hydrofoam. Curing occurs and the strength of the entire pipe member can be increased.

If the pipe member is a steering hanger beam, the rigidity on the driver (driver's seat) side and the assistant (passenger seat) side can be formed with desired rigidity.

When the steering hanger beam is a straight pipe structure that does not require bending, the strength and rigidity required for the hydroform can be satisfied without requiring bending. Further, since the mounting work and welding work of the reinforcing metal fitting are not required, the number of man-hours can be reduced, and the number of parts and the weight can be reduced.

FIG. 1 is an external view of a steering hanger beam formed by applying the pipe member forming method according to the present invention. Explanatory drawing of expanding and expanding diameter processing Hydroform principle diagram It is explanatory drawing of shaping of a driver side end part, (a) is expanded by expanding and (b) is hydrofoam. It is explanatory drawing of the molding of the assistant side end, (a) is expanded by expanding, (b) is hydrofoam It is explanatory drawing of the other steering hanger beam shape | molded by applying the shaping | molding method of the pipe member which concerns on this invention, (a) is an external view, (b) is the AA sectional view expanded arrow view of (a). , (C) is a cross-sectional enlarged view of the BB line of (a), (d) is a cross-sectional enlarged view of the CC line.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. As shown in FIG. 1, a steering hanger beam 1 formed by applying the pipe member forming method according to the present invention includes a driver side end 2, a driver side 3, a center driver side 4, and a center assistant side 5. , Assistant side 6 and assistant side end 7.

  The steering hanger beam 1 is formed into a desired shape by subjecting a pipe (steel pipe) having an outer diameter A (for example, 42.7 mm) and a plate thickness B (for example, 1.4 mm) to bending or bending. Is done. As the diameter expansion processing, the expansion of the diameter of the pipe using the expansion punch (the expansion of the expansion diameter process), and compressing the pipe axial direction while applying hydraulic pressure to the pipe expanded by the expansion of the expansion diameter. Thus, a hydroform (hydroform process) for expanding the diameter is used.

  As shown in FIG. 2, the mold 10 including a pair of clamp molds and the above-described push-punch punch 11 having a substantially conical tip are used for the press-expanding and expanding process. A cavity 10 a for expanding the diameter of the pipe 12 is formed in the mold 10.

  In order to mold using the mold 10, first, the pipe 12 is inserted into the mold 10, and the clamp mold constituting the mold 10 is closed. Next, the expansion punch 11 is press-fitted into the pipe 12, and the diameter of the pipe 12 is expanded by the shape of the cavity 10 a and the expansion punch 11.

  As shown in FIG. 3, the hydroform refers to a pipe 12 that is filled with a liquid (for example, water) 14 in a pipe 12 set in a hydroform mold 13 including an upper mold 13 a and a lower mold 13 b, and an internal pressure is applied to the pipe 12. At the same time, the pipe 12 is compressed in the length direction with a tool 15 such as a hydraulic cylinder (shaft pushing). The pipe 12 after molding is shortened, but the plate thickness is hardly changed. This is a technique that can be greatly deformed and can form the pipe 12 into a complicated shape.

As shown in FIG. 4A, the driver side end 2 is molded by first inserting the pipe 12 into the mold 10 and closing the clamp mold constituting the mold 10. Next, the expansion punch 11 is press-fitted into the end portion of the pipe 12 to expand and expand the diameter (from the outer diameter of 42.7 mm to the outer diameter of 60.5 mm).

Next, as shown in FIG. 4 (b), the end of the pipe 12 whose diameter has been expanded by press-fitting the expansion punch 11 is set in the hydroform mold 13, and the hydroform punch 15 is pressed against the pipe 12 and pressurized. Perform the seal. Next, the liquid 14 is filled into the pipe 12, and the end of the pipe 12 whose diameter is expanded by the expansion punch 11 is expanded by axial pressing by the hydroform punch 15 and internal pressure by the liquid 14 (from the outer diameter of 60.5 mm to the outer diameter). 80 mm). Thus, the driver side end 2 is formed.

  In this way, after the expansion by the expansion punch 11 is performed, only the driver side end portion 2 is formed, so that the processing pressure can be reduced and the expansion time can be reduced. Furthermore, the hydroform equipment can be simplified by reducing the applied pressure.

The molding of the driver side 3 is performed by pressing and expanding the driver side end 2 using the molding die 10 to further press the expansion punch 11 into the pipe 12 to expand and expand the diameter (outer diameter 42.7 mm). The outer shape is 60.5 mm.

Further, in the molding of the central driver side 4, as in the molding of the driver side end 2, first, the pipe 12 is inserted into the molding die 10, and the clamp die constituting the molding die 10 is closed. Next, the cross-sectional peripheral length that is insufficient in bending is preliminarily inserted, and the punch 11 is press-fitted into the pipe 12 to press-expand and expand the diameter (from an outer diameter of 42.7 mm to an outer diameter of 52 mm).

Next, the two locations 4a and 4b of the pipe 12 whose diameter has been expanded by press-fitting the expansion punch 11 are subjected to press bending. Further, the pipe 12 is set in the hydroform mold 13 by pressing or bending, and the liquid 14 is pressed or bent and filled in the pipe 12, and is expanded by the internal pressure of the liquid 14 and pressed using the punch 11. Performs correction molding of deformed parts by expanding diameter, pressing, or bending bending. Thus, the center driver side 4 is formed.

Similarly to the molding of the driver side end 2, the center assistant side 5 is molded first by inserting the pipe 12 into the molding die 10 and closing the clamp die constituting the molding die 10. Next, the cross-sectional peripheral length that is insufficient in bending is preliminarily inserted, and the punch 11 is press-fitted into the pipe 12 to press-expand and expand the diameter (from the outer diameter of 42.7 mm to the outer diameter of 45 mm).

Next, the two locations 5a and 5b of the pipe 12 expanded by press-fitting of the expansion punch 11 are pressed or bent. Further, the pipe 12 is set in the hydroform mold 13 by pressing or bending, and the liquid 14 is pressed or bent and filled in the pipe 12, and is expanded by the internal pressure of the liquid 14 and pressed using the punch 11. Performs correction molding of deformed parts by expanding diameter, pressing, or bending bending. Thus, the center assistant side 5 is formed.

Thus, in the molding of the center driver side 4 and the center assistant side 5, after the expansion and the press or bender bending process using the expansion punch 11, the deformation by the expansion and the press or the bending process is performed. Since the internal pressure correction molding by hydroforming is performed on the portion, cracks do not occur even if the limit value of elongation is approached, and a necessary shape can be ensured.

The assistant side 6 is not particularly molded, and the assistant side 6 remains the pipe (outer diameter 42.7 mm, plate thickness 1.4 mm) 12.

  As shown in FIG. 5 (a), the assistant side end 7 is formed by first setting the end of the pipe 12 in a hydroforming mold 13 and then using a hydraulic cylinder (not shown) for pushing the shaft used for the hydroforming. The punch 11 is attached to the tip, and the punch 11 is press-fitted into the end of the pipe 12 before the hydroforming to increase the diameter (outside diameter 42.7 mm to 60.5 mm).

Next, as shown in FIG. 5 (b), the end of the pipe 12 whose diameter has been expanded by press-fitting the expansion punch 11 is pressed against the hydroform mold 13 with the tapered portion 11 a of the expansion punch 11. Seal when pressed. Next, the liquid 14 is filled into the pipe 12, and the deformed portion is subjected to correction molding by the expanding and expanding diameter using the punch 11 with the internal pressure by the liquid 14. Thus, the assistant side end 7 is formed.

  In this way, after expanding and expanding the diameter by the expanding punch 11 attached to the hydraulic cylinder for pushing the shaft, the pipe 12 is pressed against the hydroforming mold 13 by the taper portion 11a of the expanding punch 11, and a seal at the time of pressurization is applied. Since the liquid 14 is filled, the space corresponding to the volume occupied by the expansion punch 11 does not need to be filled with the liquid 14, so that the liquid 14 can be reduced and the liquid filling time can be shortened.

  As described above, the molding of the driver side end 2, the driver side 3, the center driver side 4, the center assistant side 5, the assistant side 6, and the assistant side end 7 constituting the steering hanger beam 1 is expanded. Hydro expansion process using the punch 11 and hydrostatic pressure applied to the pipe 12 expanded in the expansion process to perform internal pressure expansion, correction molding, correction expansion, etc. Since the process is performed in combination with the foam process, the productivity of the steering hanger beam 1 is improved.

In addition, the pipe 12 is subjected to processing such as internal pressure expansion, correction molding, and correction diameter expansion by hydroforming after the pipe 12 has been subjected to expansion and diameter expansion processing using a press expansion punch or press or bender bending. Work hardening occurs in the whole pipe 12, and the strength of the whole pipe 12 can be increased.

  Next, as shown in FIG. 6A, the steering hanger beam 21 in the case where there is a margin in the space to be attached becomes a linear pipe structure that does not require bending. For such a steering hanger beam 21, first, a pipe having an outer diameter and a plate thickness that does not become an excessive specification is selected, and an optimum cross-sectional shape of a portion that does not satisfy the required strength and rigidity with the pipe shape as it is. Find out.

  Next, by applying the above-described hydroform (hydroform process), each part 21a, 21b, 21c of the pipe is formed into an optimum cross-sectional shape as shown in FIGS. The steering hanger beam 21 is produced.

By applying such a hydroform (hydroform process), it is possible to reduce the man-hours and reduce the number of parts as the mounting work and welding work of the reinforcing brackets required in the conventional technology are not required. Weight can be reduced.

According to the present invention, the pipe member can be expanded / modified / expanded while keeping the thickness reduction rate of the pipe member at 30% or less, so that the required rigidity is ensured without increasing the weight or the number of parts. It is possible to provide a method for forming a pipe member. In particular, when applied to a steering hanger beam, the rigidity on the driver (driver's seat) side and the rigidity on the assistant (passenger seat) side can be formed with desired rigidity.

DESCRIPTION OF SYMBOLS 1,21 ... Steering hanger beam, 2 ... Driver side edge, 3 ... Driver side, 4 ... Center part driver side, 5 ... Center part assistant side, 6 ... Assistant side, 7 ... Assistant side end part, 10 ... Mold , 11 ... Punching punch, 12 ... Pipe, 13 ... Hydrofoam mold, 14 ... Liquid.

Claims (1)

A pipe member forming method in which a plate thickness reduction rate is maintained at 30% or less and subjected to diameter expansion processing and bending processing to form a desired shape, wherein the pipe member is horizontally mounted in the width direction of an automobile. This is a steering hanger beam for attaching the ment panel to the body, and the diameter expansion processing is performed by a hydraulic expansion in the expanded diameter expanding process using an expanded punch, and in the pipe expanded in the expanded diameter expanding process. The steering hanger beam consists of a driver side end, driver side, center driver side, center assistant side, assistant side, assistant side end. The end on the driver side is expanded and expanded by hydrofoam, and the driver side is expanded and expanded. The center driver side is expanded by press or bender after pressing and expanding the diameter and further corrected by hydroform, the assistant section at the center is expanded after pressing and expanded and further corrected by hydroform, and the assistant side is processed. No, the molding method of the pipe member assistant side end, characterized in Rukoto are respectively formed in the enlarged diameter by hydroforming.

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