JPH0747171Y2 - Preheating structure around the sprue of a casting machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to improvement of a preheating structure of a sprue part of a low-pressure casting machine, for example.

(Prior Art) Conventionally, for example, in a low-pressure casting machine in which gas pressure is applied to a molten metal sealed in a crucible and the molten metal is injected into the cavity through the stoke, a spout is provided above the stalk for guiding the molten metal into the cavity. Section is provided. Then, the molten metal is filled in the cavity by pressurization to maintain the pressing force,
When the molten metal begins to solidify and reaches the upper part of the sprue, pressurization is stopped and the molten metal in the lower part is dropped from the sprue and returned to the inside of the crucible. When solidified, a lump is mixed in the molten metal in the crucible, or the sprue is clogged, which lowers the effect of the feeder. Therefore, a preheating mechanism is generally provided around the sprue part. As the preheating mechanism, for example, the fourth
As shown in the figure, the heater 52 is embedded inside the sleeve 51 or the like at the lower part of the spout, or as shown in FIG.
A method is known in which a heater 52 is wound around the outer periphery of 51 or the like.

(Problems to be solved by the invention) However, in the heater embedding method as shown in FIG.
Since it is necessary to cover the periphery of 52 with a protector, a heat-resistant material, etc. and embed it, there is a problem that the thickness of the sleeve 51 and the like becomes thicker, and if a disconnection or the like occurs inside, it is not enough to replace only the heater. Moreover, since it is difficult to uniformly embed the heater wire, there is a problem that the temperature cannot be precisely controlled.

On the other hand, in the heater winding method as shown in FIG. 3, there is a problem in adhesion with the sleeve 51 and the like, and there is a problem that the outside is not protected. That is, when the adhesion is poor, the heating effect is naturally inferior, and when it is not protected externally, it is easily damaged by rubbing or the like.

(Means for Solving the Problem) In order to solve the problem, the present invention provides a preheating mechanism on the stalk lid connected to the sprue, and provides a thin wall portion on the peripheral side wall of the stalk lid. Then, a small-diameter heater was wound around this thin portion. The thin heater was covered with a sprayed layer.

(Function) There is no need to bother with burying inside, and the sprayed layer also improves the adhesion of the heater. Therefore, the temperature raising efficiency is improved, and the thickness can be made uniform, so that precise temperature control can be performed. Further, even if the heater is broken, it can be easily repaired.

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

FIG. 1 is a vertical sectional view of the entire casting machine, and FIG. 2 is a partially enlarged sectional view of a stalk cover.

The preheating structure of the present invention is, for example, a low pressure casting machine 1 shown in FIG.
The low-pressure casting machine 1 is equipped with a crucible 3 in a holding furnace 2 in a well-known manner, and a replenishment port 9 is provided in the crucible 3.
The molten metal 4 made of aluminum alloy or the like sealed from the above is pressurized by compressed air or an inert gas from the gas passage 5 and injected into the cavity 8 of the die 7 from the stalk 6. The upper die 11 of the die 7 can be moved up and down by driving the hydraulic cylinder unit 12, and a cavity 8 is formed between the upper die 11 and the lower die 13 when the die is closed.

On the other hand, in the upper part of the stalk 6 of this casting machine, an intermediate stalk
15 is provided, and a stalk lid 16 is further provided on the intermediate stalk 15. The intermediate stalk 15 and the stalk lid 16 are provided when, for example, there are a plurality of gates to be injected into the cavity 8, and the gate portion of the stalk lid 16 has a sprue collar as a sprue, respectively. 17 is connected. The preheating structure of the present invention is constructed on the stalk cover 16, which will be described below with reference to FIG.

As described above, the stalk cover 16 includes the gate portion 18 that communicates with the spout collar 17. The gate portion 18 and the spout collar
A heat insulating member 19 is provided at the connecting portion of 17. Even if the solidification of the molten metal proceeds to the portion of the spout collar 17 above the heat insulating member 19, it is desirable to prevent the solidification around the gate portion 18 below the heat insulating member 19.

Therefore, for example, a heater groove 20 is formed on the outer circumference of the wall surface of the stalk lid 16 made of FC, and the peripheral side wall is a thin portion 21. A small heater wire 22 having a diameter of 3 mm, for example, is wound around the heater groove 20. And the thickness of the thin portion 21 is, for example,
The thickness is about 10 mm, which is about 1/3 of the thickness of the conventional embedded type, which is about 30 mm. In other words, when embedding as in the past, the diameter of the heater wire is 10 mm to 12 mm due to the protective body etc.
This is because the diameter must be extremely large, and in order to secure the required strength, the wall thickness needs to be about three times the heater wire diameter. Also, the thin heater wire wound in this way
Molybdenum, which is a refractory metal, is thermally sprayed on 22 to form a molybdenum sprayed layer 23. Therefore, the adhesion between the small-diameter heater wire 22 and the stalk lid 16 is increased, and the temperature raising efficiency is extremely good. Further, the thickness of the thin portion 21 can be made uniform, so that the temperature control becomes precise, and for example, the minimum temperature of the stalk lid 16 can be controlled at 550 ° C. ± 10 ° C.
Needless to say, the sprayed metal is not limited to molybdenum.

In addition, the preheating structure of the present invention thus constructed does not have manufacturing difficulties as in the conventional embedded type, and can easily cope with a situation such as a break in the heater wire. Also, the adhesiveness is better than that of the simple winding method, and the temperature can be effectively raised.

Therefore, the molten metal 4 in the crucible 3 shown in FIG.
The gas pressure from rises in the stalk 6, and the intermediate stalk 1
5, through the spout collar 17, the cavity 8 is filled.
Then, when the gas pressure is maintained as it is, the molten metal 4 in the cavity 8 gradually begins to solidify from the portion far from the sprue, and solidification proceeds to the portion of the sprue collar 17. During this time, the molten metal in the vicinity of the gate portion 18 which is preheated by the small-diameter heater wire 22 does not solidify, and the feeder effect is exerted to the end. Then, when the solidification is completed and the gas pressurization is stopped, the molten metal near the gate portion 18 falls into the crucible 3. At this time, the solidified mass does not mix in the crucible.

(Effects of the Invention) As described above, the preheating structure around the sprue of the present invention has been able to improve the conventional problems with a very simple and inexpensive structure. For this reason, the preheating shot can be reduced to about half that of the conventional one, and there is no clogging of the sprue, so that the effect of the feeder is sufficiently exerted, and a high-quality cast product can be cast.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of the entire casting machine, FIG. 2 is a partially enlarged view of a stalk lid showing a preheating structure of the present invention, and FIGS. 3 and 4 show conventional examples of the preheating structure. In the figure, 1 is a casting machine, 3 is a crucible, 6 is a stalk, and 8
Is a cavity, 15 is an intermediate stalk, 16 is a stalk lid, 21
Indicates a thin portion, 22 indicates a thin heater wire, and 23 indicates a molybdenum sprayed layer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shin Otsubo 1-10-1 Shin-Sayama, Sayama-shi, Saitama Honda Engineering Co., Ltd. (56) Bibliographic references Sho 63-33356 (JP, U) 53-67815 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A preheating structure for preheating a gate of a casting machine by a heater, wherein the casting machine includes a stalk lid connected to the gate, and a thin wall portion is provided on a peripheral side wall of the stalk lid. A preheating structure around the sprue of a casting machine, characterized in that the heater is wound and the small diameter heater is covered with a sprayed layer.