JPS603941A - Casting method of cylindrical body - Google Patents

Abstract

PURPOSE:To improve the yield of pouring without the need for separately providing a riser in the case of casting a cylindrical body having a projecting part on the outside circumference by providing a runner and gate to the inside of the cylindrical body. CONSTITUTION:The molten metal poured from a runner space 39 enters a cavity 37 for forming a wheel hub 11 by flowing through a gate space 41. A flange 15 which is the outside flank and projecting part of a cylindrical body 13 formed by metallic molds after the entry therein is solidified faster than the inside flank of the body 13 formed by a core 35 as well as a runner 21 and a gate 17. Since the space 39 and the space 41 are enclosed by the cavity 37, these spaces are heated by the quantity of the heat possessed by the molten metal entering the cavity 37 and as a result the molten metal stored in these spaces 39, 41, i.e., the gate 17 and the runner 21 are hardly solidifiable.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a casting method suitable for casting a cylindrical body having a protrusion on its outer periphery, such as a wheel hub.

A conventional casting method for this type of cylinder uses a sand mold to form a weir 17 at the tip of a flange 15, which is a protrusion provided on the outer surface of the cylinder 13, as shown in the wheel hub 11 of FIG. Several feeders 19 were provided through the feeders 19, and sprues 23 were provided through the runners 21 of these feeders 19.

However, in addition to the runner 21, such a conventional casting method also includes several risers 19.19. ..., the pouring yield (ratio of product weight to cast weight) decreased, and since these feeders 19 and runners 21 were provided outside the cylinder 13, the mold inside the flask was The space occupied by the molten metal becomes large, and since all molds use sand molds, the cooling rate of the molten metal becomes slow.
Also, the cross-sectional area of the weir 17 was made larger in order to make it slower than the flange 15. As a result, there have been various drawbacks such as difficulty in folding the wheel hub 11, which is a cast product.

An object of the present invention is to eliminate these drawbacks, and the configuration is such that when casting a cylinder having a protrusion on the outer periphery, at least the protrusion is formed by a mold, and the cylindrical body is This method of casting a cylinder is characterized by providing a runner and a weir inside the cylinder.

Embodiments of the present invention will be described below with reference to FIGS. 2 to 4.

As shown in FIG. 2, the wheel hub 11 is composed of a cylindrical body l3 and a disc-shaped flange 15 protruding from the outer surface of the cylindrical body 13. This wheel hub 11 is cast by a casting method described later, and a weir 17 is installed inside the cylindrical body 13 from the center toward the inner circumferential surface of the cylindrical body 13. A runner 21 is erected upward. Note that these 11117 and runners 21 are removed during casting finishing.

In order to cast this wheel hub 11, as shown in FIG.
3, and the inside of the cylindrical body 13 is formed using a core 35 made of core sand. The core 35 has a runner space 39 for pouring the molten metal into the cavity 37, and a title space 4 for communicating the runner space 39 and the cavity 37.
1 is provided. The end of the intertitle space 41 is located in the cavity 37 so that the final solidified portion 43 solidifies last.
They are connected at a position substantially on the back side of the portion forming the flange 15.

Therefore, when casting the cylindrical body 13 having a protrusion on the outside, for example the wheel hub 11, the runner space 39
The injected molten metal passes through the space 41 and enters the cavity 37 forming the wheel hub 11. After the penetration, the outer surface of the cylinder 13 formed by the mold and the flange 15, which is a protrusion, are more quickly exposed to G than the inner surface of the cylinder 13 formed by the core 35, the runner 21, and the weir 17. This solidifies. Further, since the runner space 39 and the title space 41 are surrounded by the cavity 37, they are heated by the heat of the molten metal that has entered the cavity 37, and as a result, the molten metal stored in these spaces 39 and 41, that is, the weir 17 And the runner 21 is difficult to solidify.

In addition, as shown in FIG.
The reason why the lower end of the cylinder 13 is formed separately using a mold 51 is to speed up the cooling of the lower end of the cylinder 13, smooth the casting surface of this lower end, and reduce manufacturing costs by repeatedly using the mold 51. This is to reduce the size of the core 35, which has a high temperature.

In the above embodiment, a flange is used as an example of the protruding part, but any protruding part may be used, for example, a protruding piece that protrudes radially on the outside of the cylindrical body.

In the casting method according to the present invention, since the runner and weir are installed inside the cylinder, these runners and weir are heated by the heat of the molten metal poured into the cavity and are difficult to solidify (therefore, Unlike the conventional method, there is no need to separately provide a riser, so the pouring yield is higher than the conventional method, and the space occupied by the mold in the flask is reduced, so the flask can be used effectively.

In addition, since at least the mold for forming the protrusion is a mold, the protrusion can be cooled quickly, and the cooling rate is different from that of the weir formed by the core, so that The structure of the casting differs at the boundary with the weir, which makes it easier to fold the weir.

Note that the weir folding operation can be made easier because the weir is less likely to solidify as described above, so the diameter can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of a cylinder body having a protruding portion on the outside, cast by a conventional casting method, and Fig. 2 is a longitudinal cross-sectional view of a cylinder body having a protruding portion on the outside, cast by the method of the present invention. 3 is a cutaway sectional view of a mold used for casting the cylinder shown in FIG. 2, and FIG. 4 is a cutaway sectional view of the same mold. 13... Cylindrical body 15... Protruding portion 17... Weir 21... Runway 31.33... Mold

Claims (1)

[Claims] +11 When casting a cylindrical body having a protrusion on the outer periphery, at least the protrusion is formed by a mold, and a runner and a weir are provided inside the cylindrical body. Casting method.