JPH07185715A - Die pre-heating device - Google Patents

Abstract

PURPOSE:To provide a die pre-heating device that its structure is simple, the die can be efficiently and uniformly pre-heated, and the suitable working environment can be maintained. CONSTITUTION:A die pre-heating device 1 is arranged between two separate dies, used to pre-heat these dies, and it consists of a frame body 9 having an outer shape of almost same shape to the outer diameter or the die, a heating surface member 11 covering the opening surface of the frame body 9 opposing to the die, and a fuel gas supplying tube 13 to supply fuel gas inside the frame body 9. The heating surface member 11 is formed with a porous matte like body that a metal fibre is sintered into a layer like, and the heat is generated by uniformly burning the fuel gas passing through the heating surface member 11 over the total heating surface member 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die preheating device for preheating a die for casting, forging, etc., which is composed of a plurality of divided dies, prior to the start of work.

[0002]

2. Description of the Related Art In a die for casting or forging,
The mold is preheated before the start of casting and forging in order to improve the molten metal flow or to reduce the defects that occur in the product. For example, in the case of a casting mold, the inside of the mold is about 400 ℃
Preheat to.

Conventionally, for such die preheating, a direct fire method has been adopted in which a flame is directly applied to the heated surface of the die in the atmosphere by a pipe burner provided with a large number of nozzles.

However, in this direct fire method, it is difficult to uniformly heat the surface to be heated having a complicated shape, so that the mold tends to warp and its life tends to be shortened. In particular, in the case of a mold having a core and protrusions, the core and protrusions are likely to be overheated, which further shortens the life of the mold.

Further, since the heating is performed in the atmosphere, the heating efficiency is poor, the preheating time is long, and the energy loss is large.

Further, it is environmentally unfavorable that soot is generated due to incomplete combustion and heat is released to the surroundings.

Therefore, according to Japanese Patent Laid-Open No. 60-158940, a body having a heat insulating lining stretched on its inner surface, a single burner attached to one side of the body, and a single burner are provided. There has been proposed a mold heating device equipped with a combustion tube which is installed in the main body and which diffuses flames almost uniformly, and an exhaust means attached to the main body. This mold heating device is interposed between the upper and lower molds with the surfaces to be heated facing each other,
A combustion chamber is defined in cooperation with the upper and lower molds, and the flame is diffused into the combustion chamber almost uniformly.

However, in this mold heating device, since the combustion cylinder must be provided in the main body, the structure becomes complicated,
Moreover, in order to diffuse the flame into the combustion chamber sufficiently uniformly to heat the mold uniformly and to completely burn it to prevent environmental deterioration due to exhaust gas, the structure of the combustion cylinder itself becomes considerably complicated, and Even with such a mold heating device, it is not always easy to completely avoid the drawbacks of the direct flame method.

[0009]

SUMMARY OF THE INVENTION In view of such a situation of the prior art, the present invention has a very simple structure, can efficiently and uniformly preheat the mold, and can maintain a good working environment. It is intended to provide a mold preheating device.

[0010]

MEANS FOR SOLVING THE PROBLEMS AND MEANS FOR SOLVING THE PROBLEMS The mold preheating device of the present invention is arranged between two molds which can be separated to preheat these molds. The heating surface is composed of a frame body having substantially the same outer shape, a heating surface member provided on the frame body and having a surface facing the mold, and a fuel gas supply pipe for supplying a fuel gas into the frame body. The member is formed of a porous mat-like body obtained by sintering metal fibers in layers, and the fuel gas passing through the heating surface member uniformly burns over the entire surface of the heating surface member to generate heat.

In preheating the mold, a fuel gas is supplied through the fuel gas supply pipe into the frame to mix fuel gas and air at a ratio most suitable for complete combustion of the gas body. Supply. This fuel gas reaches the outer surface of the heating surface member through the numerous small voids present in the member,
Ejects uniformly from the entire surface of the member. Then, when ignited by a spark plug or the like, the flame propagates to the entire surface of the heating surface member, and the fuel gas supplied thereafter stably burns with the flame attached to the surface of the member.

In this way, the burning is continued on the outer surface of the heating surface member, but this combustion is carried out with the flame adhered to the outer surface, whereby the heating surface member becomes a red heat state, and strong infrared rays are emitted. Radiate. The mold is preheated by the infrared rays (radiant heat) and high temperature exhaust gas, and the infrared rays are uniformly radiated from the entire outer surface of the heating surface member, and the heated surface of the mold is a short distance to this outer surface. The surfaces to be heated are heated uniformly and efficiently because they directly face each other.

Since the entire outer surface of the heating surface member uniformly glows red and maintains a high temperature state, the flame does not float up and, therefore, it is difficult to misfire. Further, since the fuel gas is mixed with air at an appropriate ratio before being supplied into the frame, it is almost completely burned, and therefore environmental pollution due to exhaust gas is small and the working environment is improved. Further, since the flame burns in a state of adhering to the surface of the heating surface member, the space required for completing the combustion reaction is small, and the combustion is already completed when the combustion gas hits the mold. Therefore, the disadvantage that soot reaches the mold due to incomplete combustion, which is observed when a flame is directly applied to the mold to heat the mold with a conventional pipe burner, is eliminated.

This mold preheating device has a very simple structure in which the open surface of a simple frame is covered with a heating surface member and a fuel gas supply pipe is attached to it, and therefore it is also extremely easy to manufacture. .

[0015]

EXAMPLES Hereinafter, the present invention will be described with reference to an illustrated example.

FIG. 1 is a schematic side view showing a state immediately before preheating of a casting device for aluminum die casting in which a mold preheating device according to the present invention is used to preheat a mold. 1 is a mold preheating device and 2 is a mold preheating device. It is a casting machine.

The casting apparatus 2 includes a lower mold 5 fixed to a lower base plate 4 fixed to a support column 3, and an upper mold 7 fixed to an upper base plate 6 which can slide up and down along the support column 3. Is equipped with.
The lower mold 5 and the upper mold 7 are opposed to each other, and mold surfaces 8 having a required shape are engraved on the surfaces facing each other. During casting, the upper base plate 6 is lowered to bring the lower mold 5 and the upper mold 7 into contact with each other, and the molten metal is injected into the cavity formed by the mold surfaces 8 of both. The mold surfaces 8 of the lower mold 5 and the upper mold 7 are preheated to improve the rotation.

As shown in FIG. 1, this preheating is performed by disposing the die preheating device 1 between the lower die 5 and the upper die 7 in a state in which they are vertically separated. Be seen.

FIG. 2 is a vertical sectional view of the die preheating device 1.
Reference numeral 9 denotes a frame body that forms the outer shell of the mold preheating device 1, and includes the mold 5,
The outer shape is substantially the same as the outer shape of No. 7, and has, for example, a rectangular parallelepiped shape. The upper and lower open surfaces of the frame body 9 are heated surface members 11 supported by an annular mounting piece 10 mounted on the frame body 9.
Respectively covered by. The frame body 9 also includes the frame body 9
A fuel gas supply pipe 13 that communicates with a space 12 surrounded by the heating surface member 11 is provided. This fuel gas supply pipe 13
Is connected to a fuel gas supply system described later.

The heating face member 11 is formed by sintering extremely fine fibers of metal such as stainless steel in a layered form to form a mat, and has a large number of fine voids inside.
The porosity is about 90%.

FIG. 3 is a system diagram of a fuel gas supply system connected to the fuel gas supply pipe 13. Reference numeral 14 denotes a fuel source for supplying a gaseous fuel, which corresponds to an LPG cylinder when LPG is used as the fuel, for example. The fuel from the fuel source 14 is sent to the mixer 18 via the pressure regulating valve 15, the on-off valve 16 and the flow rate regulating valve 17. Air is also supplied to the mixer 18 from an air source 19 such as a blower through an opening / closing valve 20 and a flow rate adjusting valve 21.

In this way, the fuel and air, the pressure and flow rate of which are properly adjusted, are sent to the mixer 18 to be mixed and become a heated mixed gas having an optimum ratio for combustion, for example, an excess air ratio of 1.0 to 1.2, It is supplied to the space 12 of the mold preheating device 1 through the fuel gas supply pipe 13. In this specification, this combustible gas mixture is referred to as fuel gas.

The fuel gas fed into the space 12 then flows out to the outer surface side of the heating surface member 11 through the fine voids dispersed in the heating surface member 11. The fuel gas is rectified and diffused by passing through the gap, and the heating surface member 11
Flows out from the outer surface of the plate at right angles to the surface and uniformly over the entire surface. The fuel gas that first flows out is ignited and burned by an ignition device (not shown), and this combustion is maintained by the subsequent fuel gas.

In this embodiment, the case where the preheating device is arranged apart from the two molds has been described, but it is also possible to sandwich the preheating device between the two molds to perform preheating. in this case,
The exhaust gas after combustion is exhausted to the outside through an exhaust port 23 provided in the attachment piece 10. Alternatively, the exhaust gas may be discharged through an appropriate communicating portion such as a runner provided in the molds 5 and 7.

Due to the combustion of the fuel gas, the heating surface member 11 becomes a red heat state and radiates strong infrared rays, that is, radiant heat. Then, the fuel gas that has passed through the heating surface member 11 surely burns when it reaches the outer surface of the heating surface member 11, and the flame thereof does not float up from the outer surface or go up inside the heating surface member 11, A flat flame is formed that adheres to the entire outer surface.

The preheating of the molds 5 and 7 is performed by the radiant heat from the heating surface member 11 in the red heat state and the high temperature combustion exhaust gas, and the radiant heat is radiated uniformly from the entire outer surface of the heating surface member 11. Further, the combustion exhaust gas is also uniformly generated along the entire outer surface of the heating surface member 11, and the mold surface 8 which is the surface to be heated of the molds 5 and 7 directly faces the facing surface of the heating surface member 11. Therefore, almost all of the heat generated by the mold preheating device 1 is directed to the mold surface 8 and evenly, and the mold surface 8 is heated uniformly and efficiently.

When a mold actually used was preheated using the mold preheating device 1, it took about 15 minutes to heat up to 350 ° C., and the energy consumption was 9,000 kcal. When the same mold was preheated by the conventional direct flame method, it required a heating time of about 40 minutes and energy consumption of 18,000 kcal. That is, it can be seen that the preheating by the device of the present invention can reduce the heating time by about 60% and the energy consumption by about 50% compared with the conventional direct fire method.

FIG. 4 is a graph showing the temperature rising condition of each part of the mold surface in a similar comparative experiment, in which the vertical axis represents temperature and the horizontal axis represents time. In this experiment, the temperature was measured at predetermined four points selected on the mold surface, the solid line shows the measured value when preheated by using the apparatus according to the present invention, and the dotted line shows the measured value when preheated by the direct fire method. It is shown. From this graph, it can be seen that in the preheating according to the present invention, the entire mold surface is heated uniformly and the predetermined temperature can be reached in a short time, as compared with the preheating according to the conventional method.

The fuel gas satisfactorily burns on the outer surface of the heating surface member 11 which is heated red and burns almost completely, so that the environmental pollution due to the exhaust gas is small and the working environment is improved.

[0030]

The mold preheating device according to the present invention has a simple structure and is easy to manufacture, and the mold can be preheated efficiently and uniformly, and a good working environment can be maintained.

[Brief description of drawings]

FIG. 1 is a schematic side view showing a state immediately before preheating of a casting apparatus for preheating a mold using the mold preheating device according to the present invention.

FIG. 2 is a vertical sectional view of a mold preheating device.

FIG. 3 is a system diagram of a fuel gas supply system.

FIG. 4 is a graph showing a mold temperature rising state in the mold preheating by the device of the present invention and the mold preheating by the conventional method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Mold preheating device, 2 ... Casting device, 3 ... Struts, 4 ... Lower base plate, 5 ... Lower mold, 6 ... Upper base plate, 7 ... Upper mold, 8 ... Mold surface,
9 ... Frame body, 10 ... Mounting piece, 11 ... Heating surface member, 12 ... Space,
13 ... Fuel gas supply pipe, 14 ... Fuel source, 15 ... Pressure regulating valve, 16 ... Open / close valve, 17 ... Flow control valve, 18 ... Mixer, 19 ... Air source, 20 ...
Open / close valve, 21 ... Flow rate control valve, 23 ... Exhaust port.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nao Nakamura 1-2 1-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Mitsuo Endo 3 Benten-cho, Tsurumi-ku, Yokohama-shi, Kanagawa NKK Comprehensive Design Co., Ltd. Mechanical Systems Engineering Department (72) Inventor Ryowa Yasue, 3 Benten-cho, Tsurumi-ku, Yokohama City, Kanagawa Prefecture NKK Comprehensive Design Co., Ltd. Mechanical Systems Engineering Department (72) Inventor Hideyo Tatsuta Tsurumi, Yokohama City, Kanagawa Prefecture 3 Benten-cho, Ward, N.K. Machinery & Engineering Co., Ltd. (72) Inventor, Yasushi Hayase 3 Benten-cho, Tsurumi-ku, Yokohama, Kanagawa N.K.K.

Claims (1)

[Claims] 1. A mold preheating device which is arranged between two separable molds and preheats these molds, wherein a frame body having an outer shape substantially the same as the outer shape of the mold, and the frame body. A heating surface member having a surface facing the mold and a fuel gas supply pipe for supplying a fuel gas into the frame, and the heating surface member is made of a porous porous material obtained by sintering metal fibers in layers. A mold preheating device, characterized in that the fuel gas, which is formed of a mat-like body, passes through the heating surface member and uniformly burns over the entire surface of the heating surface member to generate heat.