JP4375735B2 - Superplastic forming device - Google Patents

Description

  The present invention relates to a superplastic forming apparatus for forming an aluminum alloy or the like.

As a conventional molding apparatus, a high-temperature bulge molding apparatus is known (for example, see Patent Document 1).
JP 2002-126826 A

FIG. 2 of Patent Document 1 will be described with reference to FIG. 4 below. In addition, the code | symbol used what was described in the gazette.
FIG. 4 is an explanatory view of a conventional molding apparatus. The apparatus main body 7 of the high-temperature bulge molding apparatus includes a mold 8 composed of an upper mold 8a and a lower mold 8b, a pushing ram 9, an external heating means 10, and the like. The molding material 11 is previously heated to a temperature equal to or higher than the molding temperature (for example, 500 to 600 ° C.) by the external heating means 10, and the mold 8 has an inner surface side (side in contact with the molding material 11). A temperature adjusting mechanism 12 is arranged, and the cooling water is circulated in the water cooling pipe 13 embedded in the temperature adjusting mechanism 12, whereby the mold temperature is a constant temperature below the warm temperature (for example, 100 ° C.) during the molding process. It is controlled so that it is about 200 ° C. or so.

  In bulge forming, as described above, there is no problem even if the mold temperature is lowered to a constant temperature below the warm temperature. However, for example, in the mold for superplastic forming, the temperature of the plate material for molding (around 500 ° C. If the temperature of the mold is not raised to a temperature substantially equivalent to), the temperature of the plate material is lowered and superplastic forming becomes difficult.

  When the temperature of the mold 8 is increased in the above-described apparatus, the temperature of the press machine that applies a compressive force to the mold 8 in the up and down directions increases, and heat influences each part of the press machine.

  An object of the present invention is to suppress an increase in temperature on the press side while maintaining the temperature of a molding die in a superplastic molding die.

According to a first aspect of the present invention, there is provided a superplastic forming apparatus for superplastic forming a plate material, a molding die that can be exchanged according to a molding shape, a heating means for heating the molding die, and a heating means. A heat retaining member that surrounds the molding die so that the generated heat does not escape to the outside, and one end is connected to the molding die through the heat retaining member, the other end is connected to the press machine side, and pressed to the molding die And a transmission member that transmits a pressure force from the machine side, and a cooling means that makes it difficult for heat to be transmitted from the transmission member to the press machine is provided at a connecting portion between the press machine and the transmission member.

  In the invention according to claim 1, the heated molding die can be kept warm by the heat retaining member surrounding the molding die, and the molding die is further cooled by the cooling means provided at the connecting portion between the press and the transmission member. It is possible to prevent the heat from being transferred from the machine to the press machine, thereby suppressing the temperature rise of the press machine, and there is no concern that each part of the press machine is affected by heat.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.
1A to 1C are explanatory views showing an outline of a superplastic forming method using a superplastic forming apparatus according to the present invention, wherein FIG. 1A is a preheating step of a plate material as a workpiece, and FIG. 1B is a plate material. (C) shows the plate material forming step.

In the step shown in (a), the plate material 11 is heated to 450 to 550 ° C. (for example, 540 ° C.) by the heating device 10 and soaked.
The plate material 11 is, for example, a 5000 series (No. 5083, No. 5182) aluminum alloy plate material having a length of 1700 mm, a width of 1300 mm, and a plate thickness of 1.3 mm.
The heating apparatus 10 includes a heating furnace 13, a lower heater 14 disposed in the lower part of the heating furnace 13, an upper heater 15 disposed in the upper part of the heating furnace 13, and the upper heater 15 to be able to move up and down. A lifting device 16 attached to the upper part of the heating furnace 13, power supply switches 17, 18 for turning on / off the power supply to the lower heater 14 and the upper heater 15, a thermometer 21 for measuring the internal temperature of the heating furnace 13, and this thermometer The temperature control unit 22 is configured to control the temperature in the heating furnace 13, that is, the temperature of the plate material 11 by turning on and off the power supply switches 17 and 18 based on the temperature signal from 21.

Regarding the heating of the plate material 11, the plate material 11 is placed directly on the lower heater 14, and then the upper heater 15 is lowered by the elevating device 16 to approach the plate material 11, and the lower heater 14 and the upper heater 15 are supplied with power. Do it.
In this way, if the upper heater 15 is heated close to the plate material 11, the upper surface of the plate material 11 is not damaged such as a dent.

  In the step shown in (b), the holding means 26 and 26 provided in the conveying device 25 hold the both ends of the plate material 11 and the next forming device 30 (see (c)) from the heating furnace 13 (see (a)). Transport quickly. When the conveyance time becomes long, the temperature of the plate 11 is lowered, and a temperature difference between the surface and the inside is generated.

In the step shown in (c), the plate material 11 is blow-molded by a superplastic molding apparatus 30 (hereinafter simply referred to as “forming apparatus 30”).
The molding apparatus 30 includes a lower mold apparatus 32 including a lower mold 31, an upper mold apparatus 34 including an upper mold 33, and a mold temperature control unit 35 that controls the temperatures of the lower mold 31 and the upper mold 33.

The lower mold device 32 includes a lower connection member 36 mounted on a bolster of a press machine (not shown), a plurality of support members 37 that support the lower mold 31 by being attached to the lower connection member 36, and these support members 37, a lower heat retaining member 38 that is open on the upper side, a lower mold 31, a plurality of lower heaters 39 provided on the bottom of the lower heat retaining member 38 for heating the lower mold 31, and And a power supply switch 41 for turning on / off the power supply to the side heater 39.
The lower mold 31 is a member in which a gas passage 45 connected to a pressurized gas supply source 43 via a pipe 44 is formed. Reference numeral 46 denotes a valve provided in the middle of the pipe 44.

  The upper mold device 34 is connected to a plurality of transmission members 47 that transmit pressure to the upper mold 33, an upper heat retaining member 48 that is open at the bottom attached to these transmission members 47, and an upper portion of the transmission member 47. The upper connecting member 51 pressed by the ram of the press machine, the plurality of upper heaters 52 provided in the upper part of the upper heat retaining member 48 for heating the upper mold 33, and the power supply to these upper heaters 52 are turned on and off. The power supply switch 53 and a thermometer 54 attached to the side surface of the upper heat retaining member 48 are included.

The upper mold 33 includes an inner surface 56 that is curved upward and convex.
The upper heat retaining member 48 is a member that forms the furnace body 58 with the lower heat retaining member 37.
The thermometer 54 measures the temperature in the furnace body 58, and when the temperature in the furnace body 58 becomes constant, the temperature of the furnace body 58 becomes equal to the temperature of the lower mold 31 and the upper mold 33. .
The lower connecting member 36 and the upper connecting member 51 each include a plurality of water cooling passages 61 for flowing cooling water.

The operation of the superplastic forming apparatus 30 described above will be described with reference to FIGS.
2 (a) and 2 (b) are first operational views showing a molding process of the superplastic molding method according to the present invention.
In (a), with the lower mold device 32 of the molding apparatus 30 attached to the bolster 65 of the press machine and the upper mold apparatus 34 of the molding apparatus 30 attached to the ram 66 of the press machine, first, the lower heat retaining member 37 and The upper heat retaining member 48 is closed, the lower heater 39 and the upper heater 52 are energized to heat the inside of the furnace body 58, that is, the lower mold 31 and the upper mold 33 are heated to 400 to 500 ° C. (for example, 460 ° C.). . At this time, cooling water is allowed to flow through the water cooling passages 61 of the lower connecting member 36 and the upper connecting member 51.

In (b), the upper mold 33 is opened, the release agent is applied to both surfaces and the heated plate material 11 is inserted into the molding apparatus 30 and placed on the lower mold 31.
The release agent includes a release agent stock solution containing boron nitride (for example, L-BN5026 manufactured by Nippon Graphite Co., Ltd.), a surfactant (for example, New Coal 291-PG manufactured by Nippon Emulsifier Co., Ltd.), water, This is a mixed liquid composed of powdered boron nitride having a particle size larger than that of boron nitride contained in the mold stock solution (for example, boron nitride manufactured by BN). The mixing ratio of the mixed solution is 38 wt% of the release agent stock solution, 2 wt% of the surfactant, 50 wt% of water, and 10 wt% of boron nitride.

  When the temperature of the lower mold 31 and the upper mold 33 at this time is compared with the temperature of the plate material 11, the temperature of the plate material 11 is set higher. This is because if the temperature of the lower mold 31 and the upper mold 33 is higher than the temperature of the plate material 11, part of the plate material 11 in contact with the lower mold 31 and the upper mold 33 is further heated and easily stretched locally. It is because the part becomes easy to cut.

FIGS. 3A and 3B are second operation diagrams showing the molding process of the superplastic molding method according to the present invention.
In (a), the upper die 33 is closed, and a predetermined pressure (1000 to 1500 t (for example, 1350 t)) is applied to the upper die 33 by the ram 66.
Accordingly, the lower mold 31 and the upper mold 33 bite into the end portion of the plate material 11 to seal the periphery of the plate material 11 and prevent the plate material 11 from being displaced.

  In (b), the valve 46 is opened, and the pressurized gas is supplied from the pressurized gas supply reduction 43 through the gas passage 45 between the lower mold 31 and the plate material 11 for a predetermined time (for example, 80 seconds). Maintain state. As a result, the plate material 11 is plastically deformed along the inner surface 56 of the upper mold 33.

Thereafter, the upper mold 33 is opened, the plate material 11 is gripped by the conveying device and taken out from the molding device 30. After the plate material 11 is allowed to cool to about 200 ° C., it is cooled to room temperature by forced cooling.
Thereby, immediately after taking out the board | plate material 11 from the shaping | molding apparatus 30, the thermal distortion which arises from the nonuniformity of temperature distribution like the case where forced cooling is carried out can be prevented.

  In the present invention, since the cooling water flows through the water cooling passages 61 of the lower connecting member 36 and the upper connecting member 51 during the steps of FIGS. 2 and 3, the lower connecting member 36 and the upper connecting member 51 are cooled. It is possible to prevent the heat of the lower mold 31 and the upper mold 33 from being transferred to the bolster 65 and the ram 66 of the press machine while the lower mold 31 and the upper mold 33 are kept warm by the furnace body 58. Therefore, it is possible to prevent thermal influences on the bolster 65, the ram 66, and other parts of the press machine, thereby extending the service life of these parts.

  As described above with reference to FIG. 1, the present invention firstly uses a lower mold 31 as a mold that can be exchanged according to a molding shape in a superplastic molding apparatus 30 for superplastic molding the plate 11. Upper die 33, lower heater 39 and upper heater 52 as heating means for heating the molding dies 31, 33, and molding die so that the heat generated by these heating means 39, 52 does not escape to the outside. Furnace body 58 as a heat retaining member that surrounds 31 and 33, and transmission members 37 and 47 that transmit pressurizing force to the molding dies 31 and 33 from the press side, including a press machine and transmission members 37 and 47. In the connecting portion, the lower connecting member 36 and the upper connecting member 51 are used as cooling means for preventing heat from being transmitted from the molding dies 31 and 33 to the press machine (specifically, the bolster 65 and the ram 66 shown in FIG. 2A). Provided that To.

  The heated molding dies 31, 33 can be kept warm by the heat retaining member 58 surrounding the molding dies 31, 33, and the cooling means 36, 51 provided at the connecting portion between the press and the transmission members 37, 47. The temperature of the press can be suppressed by cooling the press and making it difficult for heat to be transferred from the molding dies 31 and 33 to the press. Therefore, there is no worry that each part of the press machine is affected by heat. Further, since the heat retaining member 58 exists between the molding dies 31, 33 and the cooling means 36, 51, the molding dies 31, 33 are not cooled by the cooling means 36, 51, and the molding dies are not cooled. It becomes possible to maintain the temperature of the molds 31 and 33 with higher accuracy.

  In the present embodiment, the cooling means is water-cooled. However, the cooling means is not limited to this, and may be cooled by a liquid other than water, or may be air-cooled by providing a plurality of fins.

  The superplastic forming apparatus of the present invention is suitable for forming an aluminum alloy.

It is explanatory drawing which shows the outline of the superplastic forming method by the superplastic forming apparatus which concerns on this invention. It is a 1st operation | movement figure which shows the shaping | molding process of the superplastic shaping | molding method which concerns on this invention. It is a 2nd operation | movement figure which shows the shaping | molding process of the superplastic shaping | molding method which concerns on this invention. It is explanatory drawing of the conventional shaping | molding apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Plate material, 30 ... Superplastic forming apparatus, 31, 33 ... Mold (lower mold, upper mold), 36, 51 ... Cooling means (lower connection member, upper connection member), 37, 47 ... Transmission member, 38, 48, 58 ... thermal insulation members (lower thermal insulation member, upper thermal insulation member, furnace body), 39, 52 ... heating means (lower heater, upper heater) , 65, 66 ... press machine (bolster, ram) .

Claims (1)

In a superplastic forming device for superplastic forming a plate material,
A mold that can be exchanged according to the molding shape,
A heating means for heating the molding die;
A heat retaining member surrounding the mold so that the heat generated by the heating means does not escape to the outside;
One end is connected to the molding die through the heat retaining member, the other end is connected to the press machine side, and a transmission member that transmits the pressing force from the press machine side to the molding die,
The connecting part between the press and the transmission member is provided with a cooling means that makes it difficult for heat to be transmitted from the transmission member to the press.
A superplastic forming device characterized by the above.

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