JP2003025045A - Cooling device of metallic mold for casting cylinder head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling device constituted so that only a core for combustion chamber can forcibly be cooled for the purpose of promotion of grain- oriented solidification in the combustion chamber without causing the temperature lowering of a lower mold. SOLUTION: A cooling passage 12 is formed in the core 9c for combustion chamber, fixed to the lower mold 3, and tubular pins 13 are individually connected with both ends of the passage. A coupler 19 at the flow-in side and a coupler at the flow-out side, are fitted to a manifold 16 fix to the outer peripheral surface of the lower mold 3, and these couplers 19c, 20c and the tubular pins 13 are individually connected with a cooling water supplying pipe 28 intensively disposed in a pipe holding space 15 with a cover plate 29. Even in the case the cooling water flows into the cooling passage 12, cooling water supplying pipe 28, etc., since the lower mold 3 itself is insulated from the heat with the cooling water supplying pipe 28 and the air layer of the pipe holding space 15, the temperature does not lower.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold (mold) for casting a cylinder head of an internal combustion engine by a low pressure casting method or the like, and particularly to a predetermined cooling of a combustion chamber core that directly controls casting of a combustion chamber. The present invention relates to a cooling device for forced cooling with a medium.

[0002]

2. Description of the Related Art When casting a cylinder head using a mold, in order to prevent the occurrence of casting defects in the vicinity of the combustion chamber, which is the most important in terms of function, it is necessary to directly control the casting of the combustion chamber. A technique for forcibly cooling the child is described in, for example, Japanese Patent Laid-Open No. 7-164100.

In this conventional technique, as shown in FIG.
For example, in the lower mold 101 to be combined with other mold elements to form a cavity as a product shape space,
Although the combustion chamber core 102 for the cylinder is arranged, the cooling passage 103 is provided in the lower mold 101, and the combustion chamber core 10 is provided.
2, cooling openings 105 with partition plates 104 communicating with the cooling passages 103 are formed respectively, and a predetermined cooling medium is allowed to flow through the cooling passages 103 and the cooling openings 105, whereby the combustion chamber core 102 Is forcedly cooled, thereby promoting the directional solidification in the vicinity of the combustion chamber and preventing the occurrence of casting defects due to the delay in solidification.

[0004]

In the prior art, since the cooling passage 103 is formed directly in the lower die 101, not only the combustion chamber core 102 but also the lower die 101 itself is cooled. Therefore, there is a natural limit to promoting directional coagulation. In particular, when water is used as the cooling medium, the temperature of the lower mold 101 is significantly reduced due to the remarkable temperature drop at the entrance of the passage where the cooling water first comes into contact with the lower mold 101 and becomes vaporized. Since unevenness is likely to occur, the ideal directional solidification is made more difficult.

Further, since the cooling passage 103 is directly formed in the lower mold 101 as described above, there is a disadvantage that the inflow port 106 and the outflow port 107 at both ends of the passage 103 are poor in freedom of position.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a structure capable of further promoting directional coagulation, which is an intended purpose.

[0007]

According to a first aspect of the present invention, a product shape portion space is formed by combining a main mold having a plurality of combustion chamber cores for shaping a combustion chamber and another mold element. And a cooling device for a cylinder head casting mold, in which a cylinder head is cast-molded by introducing molten metal into a product shape part space from a sprue part formed in the main mold, The chamber core is formed with a cooling passage through which a cooling medium for forcedly cooling the combustion chamber core is made to flow, and an inflow port and an outflow port of the cooling medium are formed at the outer edge of the main mold, respectively. The cooling passage and the inflow port and the outflow port are connected to each other by a cooling medium supply pipe.

The cooling medium supply pipe may be made of metal such as copper or steel, a heat-resistant flexible hose or the like, and the cooling medium may be water or the like in addition to cooling air.

Therefore, in the invention described in claim 1, since the cooling medium and the main mold are insulated without direct contact, only the combustion chamber core is efficiently cooled to cause directional solidification. Be able to promote. at the same time,
Since the main mold and the cooling medium do not affect each other thermally due to the above heat insulation, the cooling medium supply pipe can be freely laid out.

According to the invention described in claim 2, on the premise of the invention described in claim 1, the cooling passage formed in the combustion chamber core is formed at a position on the counter gate side of the combustion chamber core. It is characterized by

Therefore, according to the second aspect of the present invention, the mold surface temperature distribution suitable for promoting the directional solidification can be created so that the solidification proceeds in order from the part farther from the sprue part. Become.

According to a third aspect of the present invention, based on the first or second aspect of the invention, a pipe accommodating space is formed in the rear portion of the main mold on which the combustion chamber core is mounted, A cooling medium supply pipe that connects the cooling passage to the inflow port and the outflow port is arranged in the pipe accommodating space.

The invention according to claim 4 is the same as claim 3
On the premise of the invention described in (1), the cooling medium supply pipes that connect the cooling passage for each of the combustion chamber cores to the inflow port and the outflow port are concentrated in the pipe accommodation space.

Further, in the invention described in claim 5, on the premise of the invention described in claim 3 or 4, the pipe accommodating space is a concave space and is closed by a removable lid member. Is characterized by.

Therefore, in the inventions according to claims 3 to 5, in addition to the heat insulation effect by the cooling medium supply pipe between the main mold and the cooling medium, an air heat insulation effect by the air existing in the pipe accommodation space can be expected. Like Particularly, when the cooling medium supply pipes are concentratedly arranged in the pipe accommodation space as in the invention described in claim 4, the pipes can be integrated, and as in the invention described in claim 5, the cooling is performed. When the pipe accommodation space in which the medium supply pipes are centrally arranged is closed by the lid member, the pipe accommodation space becomes a closed space, which is more preferable in terms of heat insulation effect.

[0016]

According to the first aspect of the present invention, since the cooling medium and the main mold are insulated without being in direct contact with each other, the temperature of the main mold itself is not lowered and only the core of the combustion chamber is cooled. Can be cooled effectively,
In addition to achieving ideal directional solidification, directional solidification can be easily achieved when casting cylinder heads with different numbers of cylinders, when the specifications of the low-pressure casting machine that is the base are different, or when the casting method changes. , Furthermore, because the layout (routing) of the cooling medium supply pipe is free,
There is an advantage in terms of ensuring workability and safety as well as compatibility with equipment.

According to the second aspect of the invention, since the cooling passage formed in the core of the combustion chamber is formed at a position on the side opposite to the gate of the combustion chamber core, it is far from the gate. There is an advantage that a mold surface temperature distribution suitable for directional solidification can be created in order to allow solidification to proceed from a portion, and directional solidification can be further promoted.

According to the invention described in claim 3, since the cooling medium supply pipe is arranged in the pipe accommodating space formed in the main mold, in addition to the same effect as the invention described in claim 1 or 2, the cooling medium supply pipe is cooled. In addition to the heat insulation effect of the medium supply pipe, the air heat insulation effect of the air existing in the pipe accommodation space can be expected, and there is an advantage that the heat insulation effect between the main mold and the cooling medium is further improved.

According to the invention described in claim 4, since the cooling medium supply pipe for each combustion chamber core is centrally arranged in the pipe accommodating space, in addition to the same effect as the invention described in claim 3, cooling is provided. The medium supply pipes can be integrated, and space efficiency can be improved.

Further, according to the invention described in claim 5, since the pipe accommodating space is closed by the lid member, the pipe accommodating space becomes a substantially hermetically sealed space. In addition to the same effect as the invention described above, there is an advantage that the air insulation effect by the air existing in the pipe accommodation space is further improved.

[0021]

1 is a schematic view of a low pressure casting machine (LPDM = low pressure die casting machine) 1 to which a cooling device for a cylinder head casting die 2 according to the present invention is applied as a preferred embodiment. FIG. 2 shows the configuration.
Shows a schematic plan view of the lower mold 3 in the mold 2, and as is clear from the drawing, here, the V-shaped 6 cylinder 24 is used.
An example is shown in which two cylinder heads W for a valve type engine are simultaneously cast.

As shown in FIG. 1, in a low pressure casting machine 1, a lower mold 3 serving as a main mold of a cylinder head casting mold 2 is fixed to a platen 5 located above a molten metal holding furnace 4. . An intermediate die (horizontal die) 6 slidable in the left-right direction is placed on the lower die 3 and further the intermediate die 6
The upper die 7 is placed on the upper side of the upper die 7, and a cavity R as a product shape portion space is formed in a clamped state of the lower die 3, the intermediate die 6 and the upper die 7.

As shown in detail in FIG. 3 in addition to FIG. 2, a sprue part 8 is formed in the lower mold 3, and a metal combustion chamber is provided in a portion corresponding to the combustion chamber of each cylinder. Child 9
a, 9b and 9c are detachably fixed. And
When a predetermined hot water supply pressure is applied to the molten metal holding furnace 4 by a well-known means, the molten metal M in the molten metal holding furnace 4 is fed into the molten metal holding stalk 1.
0 and the sprue part 8 are introduced into the cavity R, and two cylinder heads W are simultaneously cast-molded.

FIG. 4 is a view of the lower half of the lower mold 3 shown in FIG. 3 as seen from below, and FIG. 5 is an AA line of FIG.
FIG. 6 is a cross-sectional view taken along the line, and FIG. 6 is a left side view of FIG. 4, respectively. As shown in FIG. 4, the spout portion 8 is formed so as to overlap with the position of the hot water supply stalk 10 in plan view. Besides, three combustion chamber cores 9a, 9b, 9c are mounted. Each of the combustion chamber cores 9a to 9c is fitted and held in a concave portion on the upper surface of the lower mold 3, and is firmly fixed by two bolts 11 mounted from the lower surface of the lower mold 3. A cooling passage 12 through which cooling water flows is formed in the central portion of each combustion chamber core 9a to 9c along the longitudinal direction as will be described later, and both ends of the cooling passage 12 are similarly cooled. It communicates with a tubular pin 13 which will form part of the passage 12. That is, a pair of tubular pins 13 communicating with the cooling passage 12 are welded and bonded to the lower surface of each of the combustion chamber cores 9a to 9c (the welded portion is shown by reference symbol We in FIG. 5).
Each tubular pin 13 penetrates to the lower surface of the lower mold 3, and a pipe joint 14 is attached to the open end thereof.

A concave pipe accommodating space 15 is formed on the lower surface of the lower mold 3 so as to surround the area of the hot water supply stalk 10 in a plan view, and the lower end portion of each of the tubular pins 13 described above is formed by this pipe. It faces the accommodation space 15. A pair of manifolds 16 and 17 are fixed to the outer peripheral surface of the lower mold 3 with bolts 18.
Reference numerals 6 and 17 denote inflow side couplers 19a, 19b, 1 which will function as cooling water inflow ports and outflow ports.
9c and outflow side couplers 20a, 20b, 20c are mounted in total of three sets corresponding to the number of combustion chamber cores 9a-9c. Inflow side couplers 19a,
19b and 19c and outflow side couplers 20a, 20b and 20c
Auxiliary passages 21 that communicate with each other are formed, and a pipe joint 22 is attached to each auxiliary passage 21.

The inflow couplers 19 adjacent to each other are provided.
a and the outflow side coupler 20a are connected to both ends of the cooling passage 12 of the combustion chamber core 9b, that is, both ends of the cooling passage 12 via cooling water supply pipes 23 and 24 which are cooling medium supply pipes made of copper or steel, for example. Connected to the tubular pin 13 that is formed. Similarly, the inflow side coupler 19b and the outflow side coupler 20b are connected to the tubular pin 13 connected to both ends of the cooling passage 12 of the combustion chamber core 9a via the cooling water supply pipes 25 and 26, and the remaining inflow side coupler 19c. And outflow coupler 2
0c is a tubular pin 13 connected to both ends of the cooling passage 12 of the combustion chamber core 9c through cooling water supply pipes 27 and 28.
It is connected to the. Each of the inflow side couplers 19a to 19 described above
c and the outflow side couplers 20a to 20c are connected to a coupler (not shown) provided on the casting machine 1 side, so that cooling water is supplied to the cooling passage 12 of each combustion chamber core 9a to 9c. Cooling water flows through the pipes 23 to 28,
With this, each of the combustion chamber cores 9a to 9c is forcibly cooled. A heat resistant flexible hose may be used as the cooling water supply pipes 23 to 28.

Here, each of the cooling water supply pipes 23 to
28 are concentrated in the concave pipe housing space 15, and the pipe housing space 15 is a closed space by fixing a metal cover plate 29, which is a lid member, with a screw 30 and closing the cover plate 29. Note that FIG. 4 shows a state in which the cover plate 29 is removed.

The structure of the cooling water supply system as described above is shown in FIG.
The same applies to the right half of the lower mold 3 shown in FIG.

Therefore, according to the cooling device as described above, the inflow side couplers 19a to 19c and the outflow side coupler 20a are provided.
.About.20c, the cooling water flows through the cooling passages 12 of the combustion chamber cores 9a to 9c via the cooling water supply pipes 23 to 28, the tubular pin 13, and the like, so that the combustion chamber cores 9a to 9c.
As a result, the combustion chamber portion of the cylinder head, which is the casting product to which the core shape is transferred, is forcibly cooled, but the cooling water is the cooling water pipes 23 to 28.
Since it is insulated by the tube pin 13 and does not come into direct contact with the lower mold 3, it does not cool other parts of the lower mold 3 and promotes directional solidification especially in the vicinity of the combustion chamber. Will be able to. In particular, the pipe housing space 15 in which the plurality of cooling water supply pipes 23 to 28 are centrally arranged is a hermetically sealed space, and the air insulation effect by the air present in the pipe housing space 15 can be expected, so that the lower mold 3
It becomes possible to more reliably insulate between the cooling water and the cooling water.

Moreover, as is apparent from FIG. 4, the cooling passages 12 formed in the cores 9a to 9c of the combustion chambers and the tubular pins 13 and the like attached to them are located as far as possible from the spout 8. Since it is arranged so as to be biased to a different position (a position on the side opposite to the sprue part 8), it is possible to further promote directional solidification so that coagulation proceeds in order from the part farther from the sprue part 8 in the vicinity of the combustion chamber. It can be a mold surface temperature distribution.

Since only the combustion chamber cores 9a to 9c can be intensively cooled without cooling the other parts of the lower mold 3 as described above, for example, a cylinder head having a different number of cylinders is cast. Even if the specifications of the low-pressure casting machine are different or the casting method is changed, directional solidification can be achieved very easily.

The cooling water supply pipes 23 to 28 do not necessarily have to be arranged centrally, and the pipe accommodating space 15 may be independent for each cooling water supply pipe 23 to 28, for example. However, in order to reduce the number of processing steps, all the cooling water supply pipes 23 to 2 have a single pipe accommodation space 15.
The type that accommodates 8 is more advantageous.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing a structure of an entire low pressure casting machine as a preferred embodiment of the present invention.

FIG. 2 is a schematic plan view of the lower mold shown in FIG.

FIG. 3 is a detailed plan view of the lower die shown in FIG.

FIG. 4 is a bottom view of the lower half of the lower die shown in FIG.

5 is an explanatory cross-sectional view taken along the line AA of FIG.

6 is a left side view of FIG.

FIG. 7 is a cross-sectional explanatory view of a conventional lower die for cylinder head casting.

[Explanation of symbols]

2 ... Cylinder head casting mold 3 Lower mold (main mold) 8 ... Gate 9a, 9b, 9c ... Combustion chamber core 12 ... Cooling passage 13 ... Tubular pin 15 ... Pipe accommodation space 16, 17 ... Manifold 19a, 19b, 19c ... Inflow side coupler (inflow port) 20a, 20b, 20c ... Outflow side coupler (outflow port) 23, 24 ... Cooling water supply pipe (cooling medium supply pipe) 25, 26 ... Cooling water supply pipe (cooling medium supply pipe) 27, 28 ... Cooling water supply pipe (cooling medium supply pipe) 29 ... Cover plate (cover member) R ... Cavity (product shape space) W ... Cylinder head

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Futoshi Chiba             Nissan, Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan             Inside the automobile corporation F-term (reference) 3G024 AA01 FA00 GA04                 4E093 NA01 NA10 NB05 QB05 QC02                       UA01 UC01

Claims (5)

[Claims] 1. A sprue part formed on the main mold by combining a main mold having a plurality of combustion chamber cores for controlling the molding of the combustion chamber and other mold elements to form a product shape part space. A cooling device for a cylinder head casting mold, in which a molten metal is introduced into a product shape part space to cast a cylinder head, and each of the combustion chamber cores is forcibly cooled. And a cooling medium inflow port and an outflow port are formed in the outer edge of the main mold, and the cooling passage and the inflow port and the outflow port are supplied to the cooling medium. A cooling device for a cylinder head casting die, which is characterized in that the pipes are connected to each other. 2. The cylinder head casting metal according to claim 1, wherein the cooling passage formed in the combustion chamber core is formed at a position on the counter gate side of the combustion chamber core. Mold cooling system. 3. A pipe accommodating space is formed in a rear surface of the main mold having the combustion chamber core mounted therein, and a cooling medium supply pipe connecting a cooling passage and an inflow port and an outflow port is accommodated in the pipe. The cooling device for a cylinder head casting mold according to claim 1 or 2, wherein the cooling device is arranged in a space. 4. The cooling medium supply pipe connecting the cooling passage for each combustion chamber core to the inflow port and the outflow port is centrally arranged in the pipe accommodating space. Cylinder head casting mold cooling device. 5. The cooling device for a cylinder head casting mold according to claim 3, wherein the pipe accommodating space is a concave space and is closed by a removable lid member.