JP5692974B2 - Method and apparatus for forming cylindrical body - Google Patents

Description

  The technique disclosed here relates to a molding method and a molding apparatus for a cylindrical body.

In recent years, from the viewpoint of suppressing global warming, automobiles have been required to reduce CO ₂ emissions by improving fuel efficiency. Examples of measures for this include weight reduction and hybridization of automobiles. For example, a torsion beam axle may be selected as a suspension type from the viewpoint of reducing the weight of an automobile. The torsion beam axle can reduce the weight of the suspension relative to the vehicle weight as compared to other types of suspension such as a multilink. Further, in a hybrid vehicle, a torsion beam axle tends to be adopted as a rear suspension from the viewpoint of securing an underfloor space for arranging a battery or the like. Thus, the torsion beam axle is expected to be increasingly used in the future.

  The torsion beam axle includes a trailing arm that supports the wheels and a torsion beam that extends in the vehicle width direction so as to connect the trailing arms on both sides in the vehicle width direction. The torsion beam is required to have torsional rigidity and bending rigidity. For example, Patent Document 1 discloses a U-shaped or V-shaped closed cross section by press-molding a cylindrical body so as to be crushed in the radial direction. A torsion beam is disclosed.

JP 2001-123227 A

  By the way, as described in Patent Document 1, such a torsion beam is a U-shaped or V-shaped closed cross-section by crushing a cylindrical raw tube (work) having a circular cross-section with a press molding machine. Thereafter, heat treatment is performed by heating in a heating furnace or the like and cooling in a watering chamber or the like, and the process is completed.

  However, these manufacturing procedures are independent processes for press molding, heating, and cooling, so individual equipment is required, and the overall requirements including the time required to transport the workpiece between processes are required. The time will be longer. In addition, for example, since the temperature of the workpiece is lowered during conveyance from the heating furnace to the watering chamber, it is necessary to superheat the workpiece excessively, resulting in an increase in energy related to the production. End up. That is, the conventional manufacturing method has a problem that the production efficiency is low in terms of time and energy consumption.

  The technology disclosed herein has been made in view of such a point, and an object thereof is to increase the production efficiency with respect to the molding of the cylindrical body.

The forming method disclosed herein is a method for forming a cylindrical body, the step of heating the cylindrical body set in a press molding machine, before heating the cylindrical body, during heating, and completion of heating. Water is supplied through a communication hole that communicates with the cylindrical body at at least one later timing, and the water is evaporated by heat generated by heating the cylindrical body, so that water vapor is applied so that the cylindrical body has a predetermined pressure. A step of filling, and a step of press-molding the cylindrical body filled with water vapor so as to be crushed in a radial direction by a pair of molding dies arranged relative to each other.

  According to this, since the cylindrical body set in the press molding machine is heated in the heating step, the cylindrical body can be press-molded in the press molding machine as it is after the heating. This eliminates the fact that the cylindrical body is heated in, for example, a heating furnace and then transported to a press molding machine to perform press molding, and the cylindrical body is set in each of the heating furnace and the press molding machine. The conveyance time between the heating furnace and the press molding machine is omitted. In addition, since the temperature of the cylindrical body is prevented from lowering during the conveyance between the heating furnace and the press molding machine, it is not necessary to heat the cylindrical body in anticipation of the temperature decrease, thereby saving energy. Excellent. In addition, since the cylindrical body (material) is hot or warm press molding with low strength and high ductility, the moldability of the cylindrical body is improved.

At the time of the molding, water is supplied through the communication hole communicating with the cylindrical body, and the cylindrical body is filled with water vapor by evaporating it by the heat of the heated cylindrical body. The internal pressure of the cylindrical body in the inside is set high, and the shape stability of the cylindrical body is increased.

In the molding step, the cylindrical body is pressed so as to be crushed in the radial direction by a pair of molding dies arranged relative to each other, and the cylindrical body is pressed by the pair of molding dies. by supplying water through the communicating hole in the body, while cooling the outside of the tubular member by the pair of molds, that the interior of the tubular member further comprise a step of cooling by the water .

After the molding is completed, water is supplied into the cylindrical body through the same communication hole as before the molding, so that the molded cylindrical body is directly cooled from the inside. This eliminates the need for a cooling facility for a cylindrical body such as a sprinkling chamber, and reduces the processing time by eliminating the conveyance of the cylindrical body to the sprinkling chamber or the like. Furthermore, since the temperature of the cylindrical body is not lowered during the conveyance of the cylindrical body to the watering chamber or the like, the heating of the cylindrical body may be set to the minimum heating temperature, which is saved. Excellent energy.

  Further, in the cooling step, the cylindrical body can be directly cooled from the inside thereof, while in the cooling step, by performing the state in which the cylindrical body is pressed by a pair of molds, the outside of the cylindrical body is It can be cooled by a mold that abuts it. Therefore, the molded cylindrical body can be efficiently cooled from both the outside and the inside.

  The cylindrical body is a cylindrical body having a uniform cross section, and in the heating step, the cylindrical body is heated by energization heating that causes electricity to flow through the cylindrical body set in the press molding machine. Good.

  The electric heating is advantageous in terms of energy efficiency because the temperature of the object to be heated (here, the cylindrical body) can be increased efficiently. In addition, since the time required for heating is short in the electric heating, it is advantageous in shortening the processing time. Moreover, since the cylindrical body before shaping | molding is a cylindrical body of a uniform cross section, it is heated uniformly by energization heating. In other words, even when energization heating is employed as a heating method for the cylindrical body, uneven heating temperature of the cylindrical body is avoided.

A molding apparatus disclosed herein is a pair of molding dies that are disposed so as to sandwich a cylindrical body having openings at both ends, and perform press molding so as to crush the cylindrical body in its radial direction. Before performing the press molding of the cylindrical body, a heating means for heating the cylindrical body and a supply means for supplying water to the inside of the cylindrical body through the communication hole are provided.

The supply means supplies water through the communication hole to the cylindrical body at least at one timing after heating, during heating, and after the heating, The water is evaporated by heat generated by heating the cylindrical body, and water vapor is filled so that the cylindrical body has a predetermined pressure.

  According to this configuration, since the molding apparatus has the heating means, it becomes possible to perform the press molding of the cylindrical body as it is after the cylindrical body is heated. As described above, the processing of the cylindrical body is possible. This is advantageous in terms of time and energy saving. Moreover, since the hot or warm press molding is performed, the moldability of the cylindrical body is improved.

  Moreover, since the internal pressure of a cylindrical body is made high with the water vapor | steam filled inside the cylindrical body at the time of press molding, the shape stability of a cylindrical body increases.

The supply means supplies water to the cylindrical body through the communication hole after the press molding is completed, thereby cooling the outer side of the cylindrical body with the pair of molding dies, while the inner side of the cylindrical body is by the water that is configured to cool.

  After the molding is completed, the cylindrical body can be directly cooled from the inside in the molding apparatus by supplying water into the cylindrical body by the supply means, so that no additional cooling equipment is required, and the processing time and energy saving are reduced. This is advantageous in terms of sex.

  The heating means may include an electrode that supplies electricity to the cylindrical body, and may be configured to heat the cylindrical body by energization heating.

  Adopting electric heating for heating the cylindrical body is advantageous in terms of saving energy consumption and shortening the heating time.

  As described above, in the molding method and the molding apparatus described above, the heating time and the press molding are continuously performed in the molding apparatus (press molding machine), thereby shortening the processing time and improving the energy saving.

  Further, by performing hot or warm press molding by increasing the internal pressure of the cylindrical body with water vapor filled inside, the moldability and shape stability of the cylindrical body are enhanced.

  Furthermore, if the three steps of heating, press molding and cooling are performed continuously, the processing time can be further shortened and the energy saving can be greatly improved.

It is a perspective view of a torsion beam axle. It is the II-II end view of FIG. It is sectional drawing which shows schematic structure of a shaping | molding apparatus. It is explanatory drawing which shows the shaping | molding process by a shaping | molding apparatus.

  Hereinafter, embodiments of a molding method and a molding apparatus will be described with reference to the drawings. The following description of the preferred embodiment is merely exemplary in nature.

  FIG. 1 shows a suspension of a torsion beam axle type. This torsion beam axle 1 includes two trailing arms 11 and 11 that support a wheel (not shown) and two trailing arms that extend in the vehicle width direction. 11, and a torsion beam 2 that couples 11 and 11 to each other. Although not shown, the trailing arm 11 is made of a pipe-like member having a closed cross-sectional shape, and is formed and arranged so as to be symmetrical with respect to the vehicle body center line extending in the front-rear direction.

  The torsion beam 2 is also formed of a cylindrical body having a substantially circular closed cross-sectional shape. As shown in FIG. 2, the torsion beam 2 has a recess 21 that has a U-shaped or V-shaped cross section as a result of the cylindrical body being crushed in the radial direction. However, it is formed to open downward. The concave portion 21 has a gradually changing portion whose depth gradually increases from both ends in the vehicle width direction toward the central portion.

  FIG. 3 shows a schematic configuration of a forming apparatus 3 related to forming the torsion beam 2. The molding apparatus 3 is basically a press molding machine having an upper mold 31 and a lower mold 32 that are disposed relative to each other. The molding apparatus 3 molds the torsion beam 2 having the recesses 21 by crushing in the radial direction the central portion in the longitudinal direction of the cylindrical body 4 having both ends open and having a substantially circular cross section. The upper mold 31 of the molding apparatus 3 is a mold that molds substantially the upper half of the cylindrical body 4 supported so that the cylinder axis is in the horizontal direction, and the lower surface thereof forms a molding surface 311. On the other hand, the lower die 32 is a die that molds the lower half of the cylindrical body 4, and the molding surface 321 formed from the upper surface thereof has a convex portion 322 for forming the concave portion 21 of the torsion beam 2. ing. Note that the upper mold 31 and the lower mold 32 may be interchanged, and the upper mold 31 may be provided with a convex portion for forming the concave portion 21 of the torsion beam 2. 3 schematically shows the configuration of the molding apparatus 3. The shapes of the upper die 31 and the lower die 32 shown here do not necessarily correspond to the sectional shape of the torsion beam 2 shown in FIG. 2, for example. .

  The forming apparatus 3 also has electrodes 33 and 33 attached to the respective end openings of the cylindrical body 4. The electrode 33 is attached to each end opening of the tubular body 4 made of, for example, ultra high strength steel, so that the electrode 33 is electrically connected to the tubular body 4 while being connected to the power source 34. ing. By causing electricity to flow through the electrode 33 through the electrode 33, the cylindrical body 4 is heated with heat generated by the internal resistance of the cylindrical body 4 (electric heating). The pair of electrodes 33 and 33 also has a function of supporting the cylindrical body 4 in the molding apparatus 3, and the electrodes 33 and 33 are support portions when the upper mold 31 and the lower mold 32 are opened. By being supported by 35, the cylindrical body 4 is arranged in a non-contact state with the upper mold 31 and the lower mold 32. Thus, when electricity is passed through the cylindrical body 4 through the electrode 33, the cylindrical body 4 can be effectively heated while avoiding energization of the molds 31 and 32.

  Each electrode 33 also has a communication hole 331 formed therethrough. The communication hole 331 allows the inside and the outside of the tubular body 4 to communicate with each other in a state where the electrode 33 is attached to the tubular body 4. The communication hole 331 is connected to a water supply source (not shown), and will be described in detail later. The communication hole 331 functions as a supply hole for supplying water into the cylindrical body 4, and water in the cylindrical body 4. It also functions as a discharge hole for discharging water.

  Next, the manufacturing method of the torsion beam 2 using this shaping | molding apparatus 3 is demonstrated, referring FIG. First, as shown in the process P1, the electrode 33 is attached to each opening of each end of the cylindrical body 4 having a substantially circular cross section, and the electrode 33 is supported by the support portion 35, whereby the cylindrical body 4 is molded. Set to. In this way, the cylindrical body 4 is energized in a non-contact state with the upper mold 31 and the lower mold 32 (see the arrow in the figure), and the cylindrical body 4 is heated to a predetermined temperature. While current heating has an advantage that the heating efficiency of the object is high and energy saving is excellent and the object can be heated in a short time, the object has, for example, a through hole, If the shape is not a uniform shape such as a trapezoid (the width of the trapezoid is not uniform), heating temperature unevenness occurs. Since the cylindrical body 4 is a cylindrical body having a uniform cross section with a circular cross section since it is before molding, such uneven heating temperature does not occur. For this reason, it is effective to employ energization heating in the molding apparatus 3 in that the cylindrical body can be uniformly heated while greatly reducing the heating time and energy consumption as compared with the heating in the heating furnace. .

  After the completion of the heating of the cylindrical body 4, a predetermined amount of water is supplied into the cylindrical body 4 through the communication hole 331 formed in the electrode 33 as shown in Step P2 (the white arrow in the figure) reference). At this time, water may be supplied from each of the two electrodes 33, or water may be supplied from one of the electrodes 33. Then, the water supplied by the heat of the cylindrical body 4 is evaporated, and the inside of the cylindrical body 4 is filled with water vapor. Although not shown in FIG. 4 and the like, the inside of the cylindrical body 4 is hermetically sealed by providing a check valve, an on-off valve, or the like in each communication hole 331. Filling the cylindrical body 4 with water vapor in this way has the effect of increasing the internal pressure during press molding. Therefore, what is necessary is just to adjust suitably the supply amount of the water to the cylindrical body 4 so that it may become a desired internal pressure at the time of shaping | molding. The supply of water to the tubular body 4 is not limited to after the tubular body 4 is heated, but may be performed before the heating, or may be performed while the tubular body 4 is being heated. Further, after stopping the energization, the upper die 31 may be lowered to bring the cylindrical body 4 into contact with the upper die 31 and the lower die 32 as shown in Step P2.

  If the inside of the cylindrical body 4 is filled with water vapor, the cylindrical body 4 is pressed against the lower mold 32 by lowering the upper mold 31 as shown in Step P3. As a result, the convex portion 322 of the lower mold 32 comes into contact with the lower portion of the cylindrical body 4 and presses the lower portion upward, and the concave portion 21 is formed at the lower portion of the cylindrical body 4. . This press molding has the advantage that the cylindrical body 4 becomes lower in strength and high ductility due to heating of the cylindrical body 4, so that the molding is easier than the cold molding, and the internal pressure of the cylindrical body 4 is increased. The shape is stabilized because press molding is performed in a state of increasing (see arrows in the figure). Furthermore, water vapor can maintain the temperature of the cylindrical body 4 high, and can also suppress that the temperature of the cylindrical body 4 falls at the time of shaping | molding.

  When the press molding is completed, water is supplied to the inside of the cylindrical body 4 through the communication hole 331 of one electrode 33 with the upper die 31 and the lower die 32 left as they are, as shown in Step P4. At the same time, the water inside the cylindrical body 4 is discharged through the communication hole 331 of the other electrode 33. Then, water is passed through the tubular body 4 to directly cool the inside of the tubular body 4. On the other hand, the outside of the cylindrical body 4 is cooled by the upper mold 31 and the lower mold 32 that are in contact with each other. Thus, quenching is performed by rapidly cooling the cylindrical body 4. Thus, since the molded cylindrical body 4 is cooled without being transported from the molding apparatus 3, for example, a decrease in the temperature of the cylindrical body 4 during the transport is avoided. Therefore, the heating temperature of the cylindrical body 4 can be set to a minimum temperature.

  As described above, in the molding method and molding apparatus 3 shown here, the three steps of heating, press molding, and cooling of the cylindrical body 4 are continuously performed in the same molding apparatus 3. For this reason, when each process is performed independently, the time required for transporting the cylindrical body 4 is omitted, and the processing time is shortened. In addition, since it is possible to avoid inconveniences such as a decrease in the temperature of the cylindrical body 4 during conveyance, it is unnecessary to heat the cylindrical body 4 in anticipation of the temperature decrease, for example, and energy saving can be achieved.

  Moreover, performing heating of the cylindrical body 4 by energization heating makes it possible to reduce the heating energy as well as the heating time.

  Furthermore, the press forming of the tubular body 4 is performed hot or warm, and the internal pressure of the tubular body 4 is increased by the water vapor filled inside, thereby making the formability and shape stability of the tubular body 4 stable. Increases nature.

  In addition, by cooling the cylindrical body 4 after molding with respect to the cylindrical body 4 in the molding apparatus 3, the heating temperature is set to a minimum temperature, which is advantageous in terms of energy saving. . Moreover, while cooling the cylindrical body 4 directly from the inner side and cooling the cylindrical body 4 also from the outer side by the upper mold | type 31 and the lower mold | type 32, the cooling efficiency of the cylindrical body 4 increases. In addition, you may comprise so that the upper mold | type 31 and the lower mold | type 32 may be cooled (for example, water cooling) as needed. Further, it is not necessary to supply water to the inside of the cylindrical body 4, and it is only necessary to supply water into the cylindrical body 4.

  In addition, the heating furnace, press molding machine, and watering chamber, which were conventionally required for carrying out the three steps of heating, press molding, and cooling, are no longer necessary, in terms of manufacturing equipment costs and installation area. , Will be greatly advantageous.

  In addition, in the said structure, although the cylindrical body 4 is heated by electroheating, the heating method is not specifically limited, A various heating method can be employ | adopted. In addition, there is no restriction | limiting in particular about the material of the cylindrical body 4, etc. However, when energization heating is adopted, the cylindrical body 4 is limited to a conductive material.

  Moreover, in the said structure, although the water supply supplied to the inside of the cylindrical body 4 is evaporated and it press-molds in the state with which the inside was filled with water vapor | steam, the internal pressure of the cylindrical body 4 is not raised. Alternatively, press molding may be performed.

  Moreover, in the said structure, although cooling of the cylindrical body 4 after shaping | molding is performed by supplying water to the inside of the cylindrical body 4, the cooling method of the cylindrical body 4 in the shaping | molding apparatus 3 is as follows. It is not limited to this. In addition, after the molded tubular body 4 is conveyed from the molding apparatus 3 to the watering chamber, it may be cooled.

  Furthermore, in the above configuration, water is supplied through the communication hole 331 formed in the electrode 33 so that both the generation of water vapor and the cooling of the tubular body 4 are performed. You may form a supply port and the supply port of the water for cooling separately. In addition, the opening for supplying water to the inside of the cylindrical body 4 is not limited to being formed in the electrode 33.

  In addition, the molding method and the molding apparatus 3 are suitable for manufacturing a torsion beam of a torsion beam axle, but are not limited thereto, and other automobile parts such as a cylindrical automobile part such as a door impact beam or an instrument panel member. In addition, the present invention can be widely applied to the production of automobile parts that can be formed into a cylindrical shape, such as bumper reinforcement, A pillar, and B pillar. Furthermore, this technology can be widely applied to the manufacture of various other parts as well as automobile parts.

  As described above, the molding method and molding apparatus disclosed herein are effective in shortening the processing time and saving energy in the molding of a cylindrical body. For example, in the production of a torsion beam, the door impact beam, the instrument panel, etc. It is useful for manufacturing various automobile components such as members and various parts other than automobile components.

3 Press molding machine 31 Upper mold (mold)
32 Lower mold (molding mold)
33 Electrode (heating means)
331 communication hole (supply means)
34 Power supply (heating means)
4 Tubular body

Claims (4)

Heating the cylindrical body set in the press molding machine,
Before heating the cylindrical body, during the heating, and at least one timing after the heating is completed , water is supplied through the communication hole communicating with the cylindrical body, and the cylindrical body is heated by the heat. Evaporating the water and filling the water vapor so that the cylindrical body has a predetermined pressure; and
A step of press-molding the cylindrical body filled with the water vapor so as to be crushed in a radial direction by a pair of molding dies arranged relative to each other ;
In a state where the cylindrical body is pressed by the pair of molding dies, water is supplied into the cylindrical body through the communication hole, so that the outside of the cylindrical body is cooled by the pair of molding dies. A method for forming a cylindrical body comprising a step of cooling the inside of the cylindrical body with the water . The molding method according to claim 1 ,
The cylindrical body is a cylindrical body having a uniform cross section,
The said heating process WHEREIN: The shaping | molding method which heats the said cylindrical body by the energization heating which supplies electricity to the said cylindrical body set to the said press molding machine. A pair of molding dies that are disposed so as to sandwich the cylindrical body between both ends of the opening, and perform press molding so as to crush the cylindrical body in its radial direction,
Heating means for heating the cylindrical body before press-molding the cylindrical body, and
Supply means for supplying water to the inside of the cylindrical body through a communication hole ,
The supply means supplies the water to the cylindrical body through the communication hole at least one timing before the cylindrical body is heated, during heating, and after the heating is completed. The water is evaporated by heat that heats the body, and is configured to be filled with water vapor so that the cylindrical body has a predetermined pressure ,
The supply means also supplies the water into the cylindrical body through the communication hole after the press molding is completed, thereby cooling the outside of the cylindrical body with the pair of molding dies, while keeping the inside of the cylindrical body. A molding apparatus configured to be cooled by the water . In the shaping | molding apparatus of Claim 3 ,
The heating device includes an electrode for supplying electricity to the cylindrical body, and is configured to heat the cylindrical body by energization heating.

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