JPH0515399Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a vent plug that is incorporated into a mold of a core molding machine.

[Conventional technology]

One method of molding a core that is set in a main mold in order to create a hollow inner surface of a casting is to use a core molding machine. When molding a core using this core molding machine, as shown in FIG.
A lower mold 3 and an upper mold 4 for molding the core are set on the die base 2 located above, and after heating the upper and lower molds 3 and 4 in this state, the molds are formed in the upper and lower molds 4 and 3. Shell sand is injected into the hollow material forming part 5, and the shell sand is filled into the material forming part 5, thereby bonding the shell sand, and then forming the shell sand in the upper and lower molds 4, 3. Model the child. Thereafter, this core is taken out from the upper and lower molds 4, 3, and the above operations are repeated to continuously manufacture cores.

By the way, when core molding is carried out by the above method, an air vent hole 6 for air venting is formed in the upper mold 4, and air venting is performed when shell sand is blown into the material shaped portion 5. This is done reliably to prevent sand clogging (defects in molding) from occurring due to insufficient air removal. As shown in FIG. 8, this air vent hole 6 has a vent plug 7 press-fitted into a large-diameter tip opening 6a that opens in the material shape portion 5, and a rear end opening 6b that has a large diameter. It opens into a heat insulating agent storage section 4b located on the lower surface of the upper mold plate 4a which is removably fitted onto the surface of the mold 4, and the air flowing into the air vent hole 6 from the material shape section 5 is stored in the heat insulating agent storage section 4b. Part 4
After passing through the heat insulating agent 4c housed in the inside b, it is exhausted to the outside. Further, the vent plug 7 has a shape in which a slit 7b for air passage is provided on the bottom surface of the plug body 7a, which is a metal cylinder with a bottom.
The outer peripheral surface of the plug body 7a is knurled to ensure that the vent plug 7 is press-fitted into the air vent opening 6a.

[Problem to be solved by the invention] As described above, when air is bleed when shell sand is blown into the material-shaped portion 5 using the air bleed hole 6 having the vent plug 7 at the tip opening 6a, the air bleeds out. Each time this is performed, shell sand and mold release agent residue gradually adhere to the slit 7b of the vent plug 7, and the vent plug 7 becomes clogged after about 50,000 blows. Therefore, it is necessary to periodically clean or replace the vent plug 7. However, the only way to clean the vent plug 7 is to use a pen cutter to clean the slits 7b one by one, which is very time-consuming and at the same time, the rate of clearing the blockage after cleaning is only 60% to 70%. There was a problem that could only be solved to a certain extent. When replacing the vent plug 7, remove the upper mold plate 4a and heat insulator 4c from the upper mold 4, insert the shaft into the air vent hole 6 from the rear end opening 6b of the air vent hole 6, and replace the vent plug. By pressing the plug 7 toward the material shape portion 5 side, the vent plug 7 is knocked out from the tip opening 6a of the air vent hole 6, but in this case, the upper mold 4 is disassembled. However, there was a problem in that the work was extremely complicated. Also, since the outer circumference of the vent plug 7 is knurled, it is not easy to knock the vent plug 7 out of the air vent hole 6, and in some cases, the slit 7 on the bottom of the vent plug 7 may
There was also the problem that only part b was damaged and the vent plug 7 could not be knocked out from the air vent hole 6.

[Means to solve the problem]

A vent plug to be inserted into an air vent hole formed in the mold of a core molding machine is connected to a cylindrical outer cylinder with a hollow interior that is inserted into the air vent hole, and a cylindrical outer cylinder that is inserted into the outer cylinder. and a rod-shaped inner rod whose outer diameter is slightly smaller than the inner diameter of the outer cylinder, and a screw hole for screwing the vent plug to the mold on the outer periphery of the rear end of the outer cylinder. and a communication hole for communicating the outer periphery of the flange portion with the hollow portion of the outer cylinder, extending in the axial direction on the outer periphery of the distal end of the inner rod, and having a top portion connected to the inner periphery of the outer cylinder. A plurality of ribs that contact the surface are formed at equal intervals, and a slit for air release is formed between the outer cylinder and the inner rod.

[Effect]

As mentioned above, by constructing the vent plug with a separable outer cylinder and inner rod, and fixing the vent plug to the mold using screws, the vent plug can be attached to and removed from the mold. This is to facilitate cleaning of the vent plug.

〔Example〕

FIG. 1 shows a mold for molding a core incorporating a vent plug according to the present invention. In the figure, 20 is an upper mold, 21 is a lower mold, and 22 is an upper and lower mold. This is a material shape portion formed within the molds 20 and 21. Reference numeral 20a designates a heat insulating agent accommodating portion formed on the surface side of the upper mold 20, 23 a heat insulating agent stored in the heat insulating agent accommodating portion 20a, and 20b an upper mold plate fitted onto the upper surface of the heat insulating agent 23. Reference numeral 24 denotes an air vent hole drilled in the upper mold 20, the tip opening 24a of which opens into the material shape section 22, and the rear end opening 24a.
4b is open to the heat insulating agent storage section 20a, and furthermore, the portion located around the heat insulating agent 23 and the rear end opening 24b of the upper mold plate 20b is a notch 25 cut out in the shape of a disc. There is. 30 is a vent plug inserted into the air vent hole 24;
As shown in FIGS. 2 to 5, the vent plug 30 includes a cylindrical outer cylinder 31 that is inserted into an air vent hole 24 and has a hollow part 32 inside, and a hollow part of the outer cylinder 31. 32 and a rod-shaped inner rod 33 inserted into the inner rod 32. The above outer cylinder 31
is the cylindrical part 34 inserted into the air vent hole 24
and a flange portion 35 formed on the outer periphery of the rear end of the cylindrical portion 34 that fits into the notch portion 25, and this flange portion 35 has screws for attaching the outer cylinder 31 to the upper mold 20. Screw holes 36, 36 for fastening
Communication holes 37, 37 for communicating the hollow portion 32 of the outer cylinder 31 and the outer periphery of the flange portion 35 are bored. Further, the rear end opening of the hollow portion 32 located at the center of the flange portion 35 is a large diameter portion 32a as shown in the figure.
The head 40 of the inner rod 33, which will be described later, is fitted therein. In addition, the inner rod 33 has a shaft portion 38 having an outer diameter slightly smaller than the inner diameter of the hollow portion 32, ribs 39, 39, etc. provided at the tip of the shaft portion 38, and ribs 39, 39, etc. provided at the rear end of the shaft portion 38. , and a head portion 40 that fits into the large diameter portion 32a. The rib 39 extends along the outer periphery of the tip of the shaft portion 38 in the axial direction,
A plurality of ribs are formed at equal intervals, and when the inner rod 33 is inserted into the outer cylinder 31, the tops of the ribs 39, 39... contact the inner circumferential surface of the hollow portion 32, as shown in the enlarged bottom view of FIG. As shown in FIG. 2, slits 41, 41, . . . are formed at the opening at the tip of the hollow portion 32. Further, when the inner rod 33 is inserted into the outer cylinder 31, the upper peripheral edge of the inner rod head 40 that fits into the large diameter part 32a provided on the outer cylinder is inserted into the outer cylinder flange part 35. Countersunk portions 40a, 4 that fit into the head of the countersunk screw
0a is provided so that the outer cylinder 31 can be screwed to the upper mold 20 and the inner rod 33 can be fixed to the outer cylinder 21 at the same time.

In the above configuration, the vent plug 30 is assembled into the upper mold 20 by first inserting the outer cylinder 31 containing the inner rod 33 into the air vent hole 24 of the upper mold 20, and then inserting the outer cylinder 31 into the upper mold 20. After fitting the flange part 35 into the notch 25 of the upper mold 20, countersunk screws (not shown) are inserted into the screw holes 36, 36 provided in the flange part 35, and the flange part 35 is inserted into the upper mold. This is done by fixing it to 20 with screws. The upper mold 20 in which the vent plug 30 has been incorporated in this manner is combined with the lower mold 21 in the same manner as before, and the material shaped portion 2 is formed between the two.
When shell sand is blown into the core 2 to mold the core, the air that has flowed into the material shape part 22 together with the shell sand flows through the slits 41, 41... formed at the tip of the vent plug 30 into the outer cylinder 31 and the inner The flange portion 35 passes through the gap formed between the rod 33 and the flange portion 35.
The air passes through the communication holes 37, 37 formed in the air, passes through the heat insulating agent 23, and is exhausted to the outside. In addition, if the slits 41, 41... of the vent plug 30 become clogged by repeating the above operation, first remove the countersunk screw, and then remove the copper pipe from the material shape part 22 side of the upper mold 20. By pressing the outer cylinder 31 of the vent plug 30 upward using a wooden hammer, the entire vent plug 30 is inserted into the upper mold 20.
Knock it out. After that, the inner rod 33 is taken out from the outer cylinder 31 of the vent plug 30 outside the upper mold 20, the hollow part 32 of the outer cylinder 31 and the outer peripheral surface of the inner rod 33 are cleaned, and at the same time, the upper mold The air vent hole 24 of No. 20 is also cleaned. And after this, inner bar 33
is inserted into the outer cylinder 35, and in this state, the vent valve 30 is again inserted into the air vent hole 24 and fixed with screws. In this way, the vent plug 30
Removing the inner rod 33 from the outer cylinder 31 and cleaning the inner rod 33 and outer cylinder 31 can be done very easily by removing the countersunk screws from the upper mold 20. Because it can be performed outside the room, it is easy and reliable, and the blockage removal rate can be 100%.

[Effect of idea]

As mentioned above, in the present invention, the vent plug inserted into the air vent hole formed in the entire mold of the core making machine is composed of a separable outer cylinder and an inner rod, and the outer cylinder and the inner rod are separated. A slit for air release is formed in between, and the vent plug is fixed to the mold by screwing the outer cylinder flange located on the surface of the mold to the mold. Therefore, the vent plug can be attached to and removed from the mold very easily without disassembling the mold. In addition, the slit of the vent plug can be cleaned by removing the vent plug from the air vent hole and then pulling out the inner rod from the outer cylinder, making cleaning the slit extremely easy and achieving a 100% blockage release rate. It can be done.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a mold incorporating a vent plug according to the present invention, Fig. 2 is a plan view of the outer cylinder of the vent plug, Fig. 3 is a sectional view taken along the - line in Fig. 2, and Fig.
The figure is a cross-sectional view taken along the line -- in Figure 2, Figure 5 is a side view of the inner rod of the vent plug, Figure 6 is an enlarged bottom view of the vent plug, and Figure 7 is the upper and lower molds set in the core molding machine. FIG. 8 is a sectional view of a mold incorporating a conventional vent plug. 20... Upper mold, 21... Lower mold, 24... Air vent hole, 30... Vent plug, 31... Outer cylinder, 32... Hollow part, 33... Inner rod, 35... Flange part , 36... Screw hole, 37... Communication hole, 3
9...Rib, 41...Slit.

Claims (1)

[Scope of utility model registration request] A vent plug to be inserted into an air vent hole formed in the mold of a core molding machine is connected to a cylindrical outer cylinder with a hollow interior that is inserted into the air vent hole, and a cylindrical outer cylinder that is inserted into the outer cylinder. and a rod-shaped inner rod whose outer diameter is slightly smaller than the inner diameter of the outer cylinder, and a screw hole for screwing the vent plug to the mold on the outer periphery of the rear end of the outer cylinder. and a communication hole for communicating the outer periphery of the flange portion with the hollow portion of the outer cylinder, extending in the axial direction on the outer periphery of the distal end of the inner rod, and having a top portion connected to the inner periphery of the outer cylinder. A vent plug characterized in that a plurality of ribs are formed at equal intervals in contact with a surface, and a slit for air release is formed between the outer cylinder and the inner rod.