JPH0713902Y2 - Core ring for high pressure casting - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a core ring for high pressure casting, and more particularly to a core ring used in a lower pressure type high pressure casting apparatus.

(Prior Art) Conventionally, for example, a lower pressure type high-pressure casting apparatus for an aluminum wheel has generally been configured as shown in FIG. In the figure, 1 is a mold, which is composed of an upper mold 2, a lower mold 3, and slide inserts 4a and 4b. The mold 1 is formed with a cavity 5 having the design surface A of the aluminum wheel as an upper side and a pouring port 6 opening from the lower side of the cavity 5. An injection cylinder 7 is arranged so as to be able to approach and separate from the mold 1 from below, and an injection chip 8 is slidably mounted inside. At the time of casting, the tip of this injection cylinder 7 is fitted and set in the pouring port 6 as shown in the drawing, and the molten metal B stored inside by the upward movement of the injection tip 8 is poured into the pouring port 6.
It is injected to the cavity 5 via. A punching metal 9 for removing oxides is attached to the pouring port 6 together with an iron pressing ring 10.

By the way, in such a lower pressure type high-pressure casting apparatus, injection is performed at a low speed in the initial stage of pouring, and high pressure is applied after the filling of the molten metal B into the cavity 5 is completed. For this reason, the vertical portion 5a of the cavity 5 forming the outer ring portion of the aluminum wheel is filled with the molten metal B by its own weight, and when the molten metal B falls, gas is entrained and a casting defect occurs. There was a problem that it was easy. Further, since the interval between the connecting portions to the vertical portion 5a is narrow, there is a problem that a poor molten metal flow easily occurs,
If it is attempted to avoid this, the gap between the cavities 5 must be widened, which causes a new problem that the thickening of the product cannot be avoided.

Therefore, as shown in FIG. 6, a cavity 5 is formed in the mold 1 so that the design surface A is on the lower side.
A lower pressurization type high pressure casting device was devised in which an iron core ring 11 was placed at the end of the pouring port 6 opened from the bottom in place of the above-mentioned pressing ring 10, and was already proposed in Japanese Patent Application No. 62-336341. Have been reported. According to this high-pressure casting apparatus, since the vertical portion 5a of the cavity 5 rises upward, the molten metal B flows upward from below during injection by the injection cylinder 7, and as a result, gas entrapment is prevented. As a result, the flow of molten metal becomes good, and the problems in the general lower pressure type high pressure casting apparatus (Fig. 5) can be largely solved.

(Problems to be solved by the invention) However, according to the new lower pressure type high pressure casting device with the design surface as the lower side, a relatively thick core ring 11 is required to secure the design surface. However, there is a problem that the weight becomes heavy and a great amount of force is required to set it in the mold 1, and the labor load increases. In addition, this core ring 11 is a molten metal B
In order to prevent the early solidification of the mold, it is usually necessary to heat it before setting it in the mold 1. However, since the thermal mass is large, it takes time to raise the temperature to the required temperature, and the casting cycle time can be extended. It becomes inevitable.

The present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to measure a lower pressure type high pressure casting which is easy to handle and can shorten the heating time. To provide a core ring for a device.

(Means for Solving the Problems) In order to achieve the above object, the present invention forms a cavity so that the design surface is on the lower side, and from below through a pouring port opened on the lower side of the cavity. It is characterized in that the core ring arranged in the pouring port of the lower pressure type high-pressure casting device for pouring the molten metal is formed by casting a ring body formed of a steel pipe.

(Function) The core ring having the above-mentioned structure is hollowed by the ring body formed of the steel pipe, the weight is light as a whole, the handling is easy, and the thermal mass is reduced. .

(Embodiment) An embodiment of the present invention applied to manufacture of an aluminum wheel will be described below with reference to the accompanying drawings.

In the following drawings, the same parts as those shown in FIG. 5 and FIG. 6 described above are designated by the same reference numerals, and the duplicated description will be omitted.

In FIGS. 1 and 2, reference numeral 20 denotes a core ring according to the present invention. The core ring 20 is formed by embedding a hollow ring body 22 inside a main body 21. The main body 21 is made of cast iron, the upper part 20a side is shaped and sized to follow the product shape on the design surface side of the hub mounting part of the aluminum wheel, and the lower part 20b side can be fitted exactly into the pouring port 6 of the mold 1. It has a shape and size. On the other hand, the ring body 22 is separately formed by bending a steel pipe into a donut shape, and is integrally cast with the main body 21 together with the casting of the main body 21.

In the core ring 20 configured as described above, since the ring body 22 is formed from a steel pipe, the lack of strength of the cast iron main body 21 is compensated for, and the hollow cross section thereof against fracture due to external pressure. Coupled with the most advantageous circular shape, sufficient strength is secured. In other words, as compared with the case where the cast iron ring is simply formed to be hollow, even if the overall wall thickness t (FIG. 2) is thinned, the strength is sufficiently guaranteed and the weight can be further reduced.

This core ring 20 is the solid core ring (6th
As in the case of FIG. 1), the mold 1 is preheated to a predetermined temperature and then the lower surface of the mold 1 is seated on the punching metal 9.
It is fitted and set in the pouring port 6 of (Fig. 1). In this set state, the upper surface of the core ring 20 contacts the cast pins 24 and 25 to prevent the pins from floating. After the core ring 20 is set, the injection cylinder 7 is connected to the mold 1, and the molten metal B is injected into the cavity 5 by its operation, and the pressurization is further performed to complete the casting. Honoko ring 20
Due to the hollow structure, the thermal mass is small, so that not only the temperature can be raised in a short time during the heating, but also the heating energy can be saved. Moreover, the weight reduction facilitates the handling and makes it easy to set in the mold 1.

The aluminum wheel obtained as described above
As shown in FIG. 3, the core 30 of the mold 30 has a core ring 20, a punching metal 9, a surplus portion (biscuit) 31 and the like integrally attached to the lower part thereof. Therefore, first of all, this is received by a die (not shown), and the casting pin 25 in the center is
The punch 32 is pushed into the escape mark of (Fig. 1) to divide the excess thickness portion 31 of the punching metal 9 or less, and subsequently, as shown in Fig. 4, the surrounding punch-out pin 24 (Fig. 1) is removed. The other punch 33 is pushed into the mark and the core ring 20 is detached from the aluminum wheel 30. As a result, the product shape of the aluminum wheel 30 is created in the trace of the core ring 20 and can be used as it is as a design surface.

(Effect of the Invention) As described in detail above, according to the core ring for high-pressure casting according to the present invention, the ring body made of steel pipe is hollowed around by casting, so that it is made thin. Even though it is possible to guarantee the strength sufficiently, it is possible to achieve a significant reduction in weight, which not only shortens the heating time but also improves workability and shortens the casting cycle time. The effect that contributed greatly was exhibited.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a core ring according to the present invention and its usage, FIG. 2 is an enlarged cross-sectional view of the core ring, and FIGS. 3 and 4 are post-processing conditions of a cast product. FIG. 5 is a sectional view of a conventional general lower pressure type high pressure casting apparatus, and FIG. 6 is a sectional view of a lower pressure type high pressure casting apparatus with an improved casting method. 1 ... Mold 5 ... Cavity 6 ... Pouring spout 7 ... Injection cylinder 20 ... Core ring 21 ... Main body 22 ... Ring body

Claims (1)

[Scope of utility model registration request] 1. A pouring port of a lower pressurizing type high pressure casting device in which a cavity is formed such that a design surface is on a lower side, and pouring is performed from below through a pouring port opened to the lower side of the cavity. A core ring arranged inside, which is formed by casting a ring body formed of a steel pipe.