JPH0646601Y2 - Lower pressure type high pressure casting mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a lower pressure type high pressure casting mold.

(Prior Art) In the high pressure casting method of the bottom pressurization method, an injection device is arranged below the mold so that it can move up and down, and the molten metal is injected into the cavity from this injection device through a pouring port provided at the bottom of the mold. It is used for manufacturing aluminum wheels, for example. In such a lower pressure type high pressure casting method, since the pouring port exists at the bottom of the mold, conventionally, this pouring port side is located on the side opposite to the design surface which is the main front surface of the product. To form a cavity,
The sprue separation surface is not left on the design surface side.

By the way, in such a lower pressure type high pressure casting method,
At the beginning of pouring, injection is performed at a low speed, and high pressure is applied after filling the cavity with the molten metal. For this reason, for example, when an aluminum wheel is targeted, the cavity portion corresponding to the outer ring portion is formed so as to fall almost vertically, and the molten metal is dropped and filled by its own weight in this portion. As a result, when the molten metal falls, gas is caught and casting defects occur,
Alternatively, there is a problem that a defective flow of molten metal is likely to occur.

Therefore, a cavity is formed so that the design surface is on the lower side, the cavity portion corresponding to the outer ring portion is raised almost vertically, and a lower ring with a nesting ring fitted to give a product shape to the pouring port is attached. A pressure type high pressure casting machine was devised and has already been reported in Japanese Patent Application No. 62-336341.

The outline of this new high-pressure casting apparatus will be described with reference to FIG. 5. In the mold 1 including the upper mold 2, the lower mold 3, and the slide inserts 4a and 4b, the design surface of the aluminum wheel is the lower side. A cavity 5 and a pouring port 6 that opens from the lower side of the cavity 5 are formed. At the opening end of the pouring port 6 on the cavity 5 side, a nesting ring 7 that gives a part of the shape of the design surface is attached together with a punching metal 8 for removing oxides, and on the other hand, below the die 1 up and down. An movably arranged injection cylinder 9 is detachably fitted and set in the pouring port 6. An injection tip 10 is slidably mounted in the injection cylinder 9, and the molten metal stored in the injection cylinder 9 is injected into the cavity 5 by the operation of the injection tip 10. However, since the cavity 5 is formed so as to rise almost vertically, the molten metal goes from the lower side to the upper side during the injection so that gas entrainment is prevented and the flow of the molten metal becomes good. Will be able to solve most of the problems in the high pressure casting method.

(Problems to be solved by the invention) However, according to the new lower pressure type high-pressure casting apparatus having the design surface as the lower side, the insert ring 7 and the punching metal 8 are as shown in FIG. In addition, the opening end on the cavity side of the pouring port 6 is configured as a large diameter hole 3a, and the large diameter hole 3a is fitted and set. In this case, in order to facilitate the setting of the insert ring 7 in the lower mold 3 and to absorb the difference in thermal expansion between the insert ring 7 and the insert ring 7, the cavity side opening end (3a) of the insert ring 7 and the pouring port 6 A fitting gap a having a relatively large distance L is provided in the fitting part of No. 3, so that the molten metal enters the fitting gap a at the time of casting and remains as a thick burr on the product design surface side. become.

That is, when the product is removed from the mold after the casting is completed, as shown in FIG. 7 (a), the product P (aluminum wheel in this case), the insert ring 7, the punching metal 8 and the biscuit 11 (unnecessary feeder) Is demolded. As shown in FIG. 7 (b), the punched metal 8 and the biscuit 11 are first separated from the punched metal 8 by pushing the punch 13 into the notch 12 of the die-cast pin (not shown) from the product P thus demolded. Is knocked out, and then, as shown in FIG. 7 (c), the other punch 15 is pushed into the recess 14 of the other die-cutting pin to knock out the insert ring 7. Then, due to the knockout of the insert ring 7, a portion that has entered the fitting gap a between the insert ring 7 and the lower mold 3 remains as a burr 16 on the design surface of the product P, and for removal of this burr 16. This requires a special deburring process, and the increase in man-hours cannot be avoided.

The present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to use a lower pressurization type high pressure casting that does not require a special process for removing burrs from a product. It is to provide the mold.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention forms a cavity so that the design surface is on the lower side, and opens a pouring port on the lower side of the cavity, In a mold for high pressure casting of a lower pressurizing method, which is formed by fitting a nesting ring that gives a part of the shape of the design surface to the cavity side opening end of the cavity of the nesting ring and the pouring port. Part or all of the fitting part with the side opening end in the height direction,
The gist is that it is formed from a tapered surface that converges toward the center of the pouring port as it goes downward.

(Function) In the lower pressurization type high pressure casting mold having the above-mentioned configuration, a part or all of the fitting portion between the insert ring and the cavity side opening end of the pouring port is partially or vertically lowered. Since it is formed from a tapered surface that converges toward the center of the pouring port as it goes toward, when the insert ring is knocked out from the product after casting, the insert ring is inserted into the burr formed in the fitting gap with the mold. A force in the radial expansion direction is applied from the child ring, and shear stress is generated at the connection between the burr that is the stress concentration part and the product due to this force in the radial expansion direction, and the burr is separated from the product together with the nest ring, The deburring process of is unnecessary.

(Embodiment) An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a lower pressurizing type high pressure casting mold according to the present invention. Note that this embodiment is applied to an aluminum wheel, and the overall structure thereof is the same as that shown in FIG. 5 described above. The description is omitted. The feature of this embodiment is that the outer peripheral surface of the insert ring 7 is tapered toward the center of the pouring port 6 as it faces downward.
The large-diameter hole 3a (FIG. 6) which is the opening end on the cavity side of the pouring port 6 is formed from the tapered surface 22 having the same inclination angle as the tapered surface 21. The fitting gap a between the insert ring 7 and the lower mold 3 is defined by the lower mold 3 of the insert ring 7.
It is necessary to ensure the distance L shown in FIG. 6 above in the horizontal direction in order to facilitate the setting of the above and to absorb the difference in thermal expansion between the two during casting. However, in this embodiment, since the outer peripheral surface of the insert ring 7 and the inner peripheral surface of the large diameter hole 3a are formed by the tapered surfaces 21 and 22, the insert ring 7 and the lower mold 3 are inclined by the inclination angle. The substantial fitting gap between them (as viewed in the direction of the surface line) has a smaller value 1 than the distance L, and therefore the thickness of the burr formed in this fitting gap a is also thin.

With such a structure, after the casting is completed, the mold is removed, and in the mode shown in FIG. 7 (b), when the punching metal (8) and the biscuit (11) are first knocked out, as shown in FIG. 2 (a). Nesting ring 7 attached to product P as shown
There is a burr 16 formed in the fitting gap a around the. Then, after that, when the nesting ring 7 is knocked out in the same manner as shown in FIG. 7 (c), this burr 16
Has a reverse taper in the knockout direction, a shearing force acts on it from the nest ring 7, and FIG.
The burr 16 is separated from the product P together with the separation of the nesting ring 7 as shown in FIG. At this time, as described above, since the thickness of the burr formed in the fitting gap a is substantially thin, the separation thereof becomes extremely easy.

The angles of the tapered surfaces 21 and 22 formed on the outer peripheral surface of the insert ring 7 and the inner peripheral surface of the large diameter hole 3a do not have to be the same as in the above embodiment, and are shown in FIG. 3, for example. As described above, the angles of the tapered surfaces 21 and 22 may be changed between the insert ring 7 and the large diameter hole 3a. Further, these tapered surfaces 21 and 22 may be partially provided in the fitting portion between the insert ring 7 and the opening end portion of the pouring port 6 by dividing the height direction thereof, as shown in FIG. 4, for example. In addition, it can be provided at a portion corresponding to a connection portion between the product P and the burr 16 (see FIG. 7).

(Effect of the Invention) As described in detail above, the lower pressurizing type high pressure casting mold according to the present invention is a fitting portion between the insert ring and the cavity side opening end of the pouring port. , Part or all of the height direction is formed from a taper surface that converges to the center of the pouring port as it goes downward, so when the knockout ring from the product after casting, The burr formed in the fitting gap with the mold is separated from the product together with the input ring, which has the effect of eliminating the need for a subsequent deburring step. Further, the taper shape has the effect of improving the fitting property of the insert ring in the mold, that is, the workability of assembling.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an essential part showing an embodiment of a lower pressure type high pressure casting mold according to the present invention, and FIGS. 2 (a) and 2 (b) are from a product obtained by this mold. Fig. 3 is a sectional view showing a knockout state of the insert ring of Fig. 3, Fig. 3 and Fig. 4 are sectional views showing the main part of a modified example of this mold, and Fig. 5 is a conventional lower pressurizing type high pressure casting mold. The sectional view shown in FIG. 6, FIG. 6 is a sectional view showing a part of the enlarged view, and FIGS. 7A to 7C are sectional views showing the knockout state of the nesting ring from the product obtained by the conventional mold. Is. 3 ... Lower mold, 6 ... Molten spout 7 ... Nesting ring, 21, 22 ... Tapered surface a ... Mating gap

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Haruhide Tanaka 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. (72) Yuo Yada 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A cavity is formed so that a design surface, which is a main front surface of a product, faces downward, and a pouring port is opened below the cavity, and the cavity side opening end of the pouring port. In a lower pressurizing type high pressure casting mold, which is formed by fitting a nesting ring that gives a part of the shape of the design surface to the part, the nesting ring and the cavity side opening end of the pouring port are fitted together. Part or all of the joint in the height direction,
A lower pressurizing type high pressure casting mold, characterized in that it is formed from a tapered surface that converges toward the center of the pouring port as it goes downward.