JP2598747Y2 - Casting models and castings - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casting model and a casting for forming a sand mold.

[0002]

2. Description of the Related Art When a casting is manufactured by a sand mold,
Care has been taken to minimize the draft of the model to improve casting yield and improve dimensional accuracy. The mold formed by the sand mold is subjected to upper and lower mold matching. At this time, mold breakage is likely to occur on the parting surface due to pressure bonding between the upper mold and the lower mold, and this causes cast flash and defects. Conventionally, chamfering of 2 to 3 mmR is performed at the corner of the parting surface to prevent the occurrence of these defects. If burrs occur on the parting surface of the mold, much work and time is required for removing the burrs. In addition, this casting work is a workplace where the grinding work using a grinder or the hanging work using a rag is frequent and the working environment is extremely poor. Japanese Utility Model Laid-Open Publication No. Hei 3-9246 discloses a method for preventing such a flash. That is, a casting model having an appropriate draft angle, wherein one or more multi-stage draft angles are further provided to the draft angle near the corner of the parting surface. In other words, the draft angle in the vicinity of the corner of the parting surface is made gentle, thereby eliminating the chamfer R at the corner and improving the mold clamping to prevent the occurrence of casting.

[0003]

However, although such a method can certainly prevent the occurrence of casting, it is not always a preferable method such as an increase in man-hours for manufacturing a model. Technology development has been strongly desired. The present invention has been made in view of such a problem, and a purpose thereof is to make the parting surfaces of the upper and lower molds free from each other so as not to be directly crimped. It is an object of the present invention to provide a casting model and a casting that can reduce production costs of a model, completely prevent the occurrence of burrs, reduce production costs, and significantly improve quality.

[0004]

The casting model according to the present invention is:
A casting model having an appropriate draft angle, wherein the parting shape of the upper model is larger than the parting shape of the lower model, and a step between the parting surface of the upper model and the parting surface of the lower model. Is 0.3 to 0.5 mm. Furthermore, the casting of the present invention is a casting having an appropriate draft angle, and the parting surface shape formed by the upper mold model is larger than the parting surface shape formed by the lower mold model, and is formed by the upper mold model. The difference between the parting surface formed and the parting surface formed by the lower mold model is 0.3 to 0.
It is a casting characterized in that it is 5 mm. If the maximum dimension at the parting surface and the minimum dimension with the draft are within the normal tolerance of the as-cast dimension of the length, more excellent effects can be obtained.

[0005] If the step between the parting surface of the upper mold and the parting surface of the lower mold of the casting model is less than 0.3 mm, the effect of preventing the formation of burrs is small. This is because the effect of preventing the occurrence of swelling does not increase, but rather gives a large step to the casting, which adversely affects the casting.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in more detail with reference to the drawings. 1 is a sectional view of a model, FIG. 2 is a sectional view of a casting, and FIG. 3 is a partially enlarged view of a parting surface of the mold of the present invention. The casting model having an appropriate draft angle has a configuration in which the parting surface shape 2 of the upper model 1 is larger than the parting surface shape 4 of the lower model 3. Therefore, there is no need to chamfer R at the corners of the parting surface as in the prior art, and it is not necessary to machine the shape into multiple draft angles, so that the production cost of the casting model can be reduced.

On the other hand, in FIG. 3, the parting surface shape 6 of the upper mold 5 is larger than the parting surface shape 8 of the lower mold 7 and a step of 0.4 mm is provided. And the parting surface shape 8 of the lower mold 7 are free from each other, and are not directly press-bonded to each other, so that the occurrence of mold breakage and casting can be completely prevented. That is, when the molten metal is poured into the mold as shown in FIG. 3, the part of the parting surface shape 8 of the lower mold 7 is washed by the molten metal rising from below the mold, and becomes a slightly rounded shape. . When the molten metal further rises, the part of the parting surface shape 6 of the upper mold 5 becomes slightly rounded. Since the step between the upper mold 5 and the lower mold 7 in this portion is only 0.3 to 0.5 mm, a good casting having no burrs on the parting surface can be obtained as the casting 9. is there.

Further, as described above, it is possible to obtain a good casting having no burrs on the parting surface, and to obtain an upper mold 5
The part of the parting surface shape 6, that is, the maximum dimension at the parting plane and the minimum dimension 10 with draft angle are set within the normal tolerance of the as-cast dimension of the length, so that the casting finish work after casting is completed. It can significantly reduce the manufacturing cost and improve the quality.

[0009]

[Effect of the Invention] As is apparent from the above description, the casting model and the casting of the present invention are free from each other so that the parting surfaces of the upper die and the lower die are not directly pressed. In addition, the production cost of the model is reduced, and the production of castings is completely prevented, and the casting work after casting can be completely abolished. Can bring about.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a model,

FIG. 2 is a sectional view of a casting.

FIG. 3 is a partially enlarged view of a parting surface of a mold.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper model 2 Parting surface shape 3 Lower model 4 Parting surface shape 5 Upper mold 6 Parting surface shape 7 Lower die 8 Parting surface shape 9 Casting 10 Minimum dimension

Claims (3)

(57) [Scope of request for utility model registration] 1. A casting model having an appropriate抜勾distribution, the parting plane shape of the upper mold model than the parting surface shape of the lower mold model to a large city, parting the parting face of the upper die model and the lower mold model
Ri surface and casting model, characterized in Succoth such as 0.3~0.5mm a step of. 2. A casting having an appropriate抜勾distribution, than parting surface shape which is molded by the lower mold model has been the parting plane shape formed by the upper mold model to a large city, the upper die model
Molded by parting surface and lower mold model
Casting, characterized in 0.3~0.5mm and such Succoth a step of parting surfaces that. 3. A process according to claim 1 or 2 castings wherein a kept within ordinary tolerance cast the largest dimension to the抜勾minimum dimension and a length imparted distribution and dimensions in the parting plane.