JPH049056Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a press die used for drawing, and particularly to a cooling device for a press die that improves its cooling capacity.

[Prior Art] In a press drawing die, after the edge of the material is pressed down by a wrinkle presser, the punch is lowered and the material is drawn into the center of the recess of the lower die. In this case, the material is bent and stretched by the punch tip and the drawing angle of the die, the flange changes shape, and the end of the material slides in to feed the material. Concave and convex beads are provided on the wrinkle pressing surface and the aperture corner, and the material inflow is controlled by the additional tension generated when passing through the bead.
Adjustment of this inflow rate prevents wrinkles and surface distortion, additional tension improves product accuracy, and ironing when passing the bead prevents flange wrinkles, but continuous processing prevents processing heat. There is a problem in that the slight thermal expansion of the mold causes instability in the product accuracy. In press drawing molds, in order to continue efficient production with stable quality, it is necessary to maintain the temperature of the mold within an optimal temperature range.

To achieve this, the general method is to install cooling piping inside the mold and circulate a refrigerant such as nitrogen gas, or to use an air nozzle from outside while the mold is open at the top dead center of the press. Methods such as cooling by blowing air onto the mold surface are used. However, the former method has space problems as the refrigerant supply device must be installed next to the press machine, and the restrictions of the complicated mold make it impossible to place the piping close to the required area. No effect is obtained. In addition, the latter method had problems such as air not reaching the inside of the mold and making noise, so both methods could not necessarily be said to be appropriate cooling methods.

[Problems to be solved by the invention] The required quality of press parts for automobiles is increasing in terms of design, cost, high surface quality, high precision, strength and durability, etc. The above-mentioned cooling methods are not perfect in achieving this, and this idea utilizes air vent holes formed on the mold surface to slightly exceed the bottom dead center of the press in areas where processing heat is intense. An object of the present invention is to provide a cooling device for a press die, which discharges compressed air at the point when the press die is cooled by adiabatic expansion of the air.

[Means for Solving the Problems] The press die cooling device of this invention consists of an upper die and a lower die, and the upper die and the lower die have press apertures in which air vent holes are formed on the die surface. In the mold, a compressed air source is connected to a specific part of the air vent hole of the mold by an air supply pipe via a solenoid valve, and the solenoid valve is operated in response to a bottom dead center signal of the press, and It is configured to send compressed air to a specific location in the air bleed hole.

[Example] An example of this invention will be described with reference to the drawings. In the figure, the press drawing die consists of a lower die 2 fixed on a surface plate 1, an upper die 3 that is movable in the vertical direction, and a wrinkle presser die 4. Gaps C and S are the drawing forming gaps at the bottom dead center of the press. It is. Concave and convex bead portions are formed at important points on the mold mating surfaces facing each other at the gaps C and S, and a plurality of air vent holes 5 are passed through the concave portions of the mold wall. Among the air bleed holes 5, one end of a flexible compressed air supply branch pipe 6 such as a vinyl tube is connected to the air bleed hole 5' at a specific position where processing heat is generated particularly intensely. The other end is connected to a joint block 7 provided in the main part of the upper mold 3. On the other hand, 8 is a solenoid valve, which is connected to a compressed air source 9 and a press bottom dead center detection switch 10, and is connected to the joint block 7 and the solenoid valve 8 through an air supply pipe 11.
is connected to.

With the above configuration, when drawing a workpiece, when the workpiece is placed at a predetermined position on the lower mold 2, a hydraulic cylinder (not shown) is activated by a pressure signal, and the upper mold 3 and wrinkle The presser die 4 descends, and the wrinkle presser die 4 first comes into contact with the workpiece, and when the pressure is further increased, the material edge of the workpiece is brought into contact with the mold matching surface gap S between the wrinkle presser die 4 and the lower die 2. The material slides on the uneven bead part inside, passes through with moderate added tension, supplies the material to the center of the concave part of the lower mold 2, and is applied by the mold matching surface gap C between the lower mold 2 and the upper mold 3. Perform drawing processing. At this time, the atmosphere within the mold mating surfaces C and S is discharged to the outside of the mold through the air vent holes 5. Next, when the upper mold 3 reaches the press bottom dead center, the solenoid valve 8 is activated in response to the bottom dead center signal of the press bottom dead center detection switch 10, and after the press drawing process is completed, the upper mold 3 and the wrinkle presser mold 4 are As the vehicle begins to ascend, it receives primary air from the compressed air supply source 9. After passing through the air supply pipe 11, the primary air is branched at a junction block 7, and then connected to a compressed air supply branch pipe 6.
The compressed air is sent to the air bleed hole 5' at a specific position among the air bleed holes 5 through the air bleed hole 5, and is released into the mold matching surface gaps C and S. The released compressed air becomes cold air according to the principle of adiabatic expansion, efficiently cooling the parts of the mold where processing heat is particularly intense, and maintaining the temperature of the mold within the optimum temperature range.
Then, when the upper mold 3 and the wrinkle presser mold 4 rise, the solenoid valve 8 stops supplying compressed air in response to a press bottom dead center release signal.

[Effects of the invention] The press die cooling device of this invention consists of an upper mold and a lower mold, and the upper mold and the lower mold are press drawing molds in which air vent holes are formed on the mold surface. , a compressed air source is connected to a specific location of the air bleed hole of the mold by an air supply pipe via a solenoid valve, and the solenoid valve is activated in response to a bottom dead center signal of the press to identify the air bleed hole. Since the structure is configured to send compressed air to the parts, the compressed air can be released into the gap between the mold mating surfaces through the air vent holes in the parts of the mold where processing heat is particularly intense, even in a cold air state close to adiabatic expansion. It is possible to cool the mold efficiently and keep the mold temperature within the optimum temperature range. Furthermore, there is no need for external cooling such as air blowing, and by using a portion of the air vent hole, the cooling device can be installed with an extremely simple structure and at low cost. Furthermore, it is possible to significantly reduce the occurrence of defects such as distortion and cracks in the pressed product due to slight thermal expansion of the mold due to processing heat generated by continuous processing.

[Brief explanation of the drawing]

The drawing is a sectional view of a main part showing an embodiment of this invention. 2...Lower die, 3...Upper die, 5, 5'...Air vent hole, 8...Solenoid valve, 9...Compressed air source, 11...
...Air supply pipe.

Claims (1)

[Scope of utility model registration request] It is a press drawing mold consisting of an upper mold and a lower mold, in which air bleed holes are formed on the mold surface, and a compressed air source is supplied to a specific location of the air bleed hole of the mold. A press mold cooling device connected to an air supply pipe via a solenoid valve, the solenoid valve being activated in response to a bottom dead center signal of the press to send compressed air to a specific location of the air bleed hole. .