JP7141366B2 - sleeve for die casting - Google Patents

Description

The present invention relates to a sleeve used for filling molten metal into a cavity in a die casting apparatus.

In die casting of non-ferrous metals such as aluminum, magnesium, zinc, tin, lead and their alloys, a cylindrical sleeve is used to fill the cavity with molten metal. One end of the sleeve communicates with the cavity, and the plunger tip enters from the other end and slides in the sleeve in the axial direction. In a horizontal type (horizontal injection type) sleeve that is used with the axial direction substantially horizontal, a pouring hole that penetrates a part of the side peripheral wall of the sleeve opens upward near the end on the side where the plunger tip is inserted. It is designed to Molten metal supplied into the sleeve through the pouring hole is pumped through the sleeve as the plunger tip advances, and fills the cavity.

In the past, general sleeves were made of steel, but since non-ferrous metals tend to react with iron, steel sleeves are prone to erosion due to contact with the molten metal to be filled, resulting in a short service life. rice field. Also, since steel has a high thermal conductivity, the temperature of the molten metal supplied into the sleeve tends to drop. When the temperature of the molten metal supplied into the sleeve drops inside the sleeve before it reaches the cavity, solidified pieces are generated. Such defects are likely to occur, and there is a problem that the mechanical strength is lowered.

Therefore, the applicant has proposed that the sleeve has a double structure consisting of an outer cylinder and an inner cylinder, and the inner cylinder that is fitted into the steel outer cylinder is a sintered composite material of titanium or a titanium alloy and ceramics (hereinafter referred to as a (referred to as "TC composite material") has been proposed and implemented (see, for example, Patent Document 1). The TC composite material has low reactivity with non-ferrous metals, and is therefore excellent in erosion resistance. In addition, while steel (SKD61) has a high thermal conductivity of 35.6 W/mK, TC composite material has a very low thermal conductivity of 7.4 W/mK, which is excellent in heat retention. It has the advantage that the temperature of the molten metal is less likely to drop. Furthermore, when the inner cylinder is formed only from ceramics, although it is possible to improve the resistance to erosion and heat retention, ceramics, which is a brittle material, has the disadvantage of low impact resistance. Since it is a composite material of and ceramics, it has the advantage of being excellent in impact resistance.

In this way, sleeves that use TC composite material, which is excellent in corrosion resistance, heat retention, and impact resistance, for the inner cylinder have a longer service life than conventional sleeves, and produce high-quality products that do not contain solidified fragments. It has the advantage of being moldable. However, when the amount of molten metal supplied to the sleeve is increased for casting larger products, or when the time interval for supplying molten metal to the sleeve is shortened to speed up the casting cycle, the inner cylinder Solidified molten metal sometimes adhered to the inner surface of the When the solidified molten metal adheres, the plunger tip rises on the adhering matter and bites into the opposing surface of the inner surface of the inner cylinder. As a result, there is a problem that the service life of the sleeve is shortened.

JP-A-3-142053

Therefore, in view of the above circumstances, the present invention provides a die casting sleeve that has a long service life even when it is used under conditions where the supply amount of molten metal is large or under conditions where the time interval between supply of molten metal is short. , is a subject.

In order to solve the above problems, the die casting sleeve (hereinafter sometimes simply referred to as "sleeve") according to the present invention is
"A cylinder having a cylindrical portion and a pouring hole that penetrates a part of the side peripheral wall of the cylindrical portion, the central axis of the cylindrical portion being substantially horizontal and the pouring hole being opened upward, the cylinder A die-casting sleeve that allows the front end of the portion to communicate with the cavity and allows the plunger tip to enter from the rear end of the cylindrical portion,
The cylindrical portion has an outer cylinder and an inner cylinder fitted into the outer cylinder,
In the cylindrical portion, the inner cylinder is formed of a sintered body of a composite material of titanium or a titanium alloy and ceramics at least in the molten metal receiving region below the pouring hole,
A cooling device is provided on the outer cylinder in the hot water receiving area.

As described above, when used under conditions where the amount of molten metal supplied to the sleeve is increased or under conditions where the time interval between molten metal supply is short, solidified molten metal adheres to the inner surface of the inner cylinder. . Such adherence of molten metal was conspicuous in the hot water receiving region, which is the portion that receives the molten metal. Therefore, when the deposits were removed by dissolution and examined, it was observed that the inner surface of the inner cylinder was gouged out at that portion, and that a large number of fine cracks were formed around it. A die-casting test was conducted while measuring the temperature of the inner surface of the inner cylinder. The temperature in the area had risen to about 500°C. As shown in FIG. 9, the mechanical strength (bending strength) of steel sharply decreases as the temperature rises, whereas the TC composite material does not exhibit a sharp drop in strength with the temperature rise, and can withstand temperatures of approximately 600°C or higher. However, when the temperature exceeds 500°C, the mechanical strength gradually decreases.

TC composite material easily stores heat due to its low thermal conductivity. It is thought that fine cracks occur on the surface of the TC composite material used for the inner cylinder due to repeated heating and cooling due to pouring and injection under these conditions. was taken. Then, it was thought that the inner surface of the inner cylinder was damaged in a process in which high-temperature molten metal entered the fine cracks, causing further erosion, and the molten metal remaining in the cracks solidified and adhered.

If damage to the inner cylinder progresses in such a process, it may be conceived to cool the "inner cylinder" so that the temperature of the inner cylinder does not become high. However, if the temperature of the molten metal drops before it reaches the cavity by cooling the inner cylinder, solidified pieces are generated and mixed in the molded product, degrading the quality of the product.

In order to balance these contradictory demands, the present invention proposes that although it is the inner cylinder made of the TC composite material that is damaged, it is not the inner cylinder that is damaged, but the outer cylinder. We adopted the method of indirectly cooling the cylinder and the method of cooling the hot water receiving area as the minimum area to be cooled. That is, the inner cylinder is made of TC composite material at least in the hot water receiving area, and the cooling device is provided on the outer cylinder in the hot water receiving area. Since the TC composite material has a very low thermal conductivity, by cooling from the outside, even if the TC composite material itself is cooled to some extent, the molten metal is not cooled and the temperature drop of the molten metal can be suppressed. can. In addition, since the TC composite material itself is cooled, it is possible to suppress the progress of damage to the inner cylinder due to the above-described process, thereby extending the service life of the sleeve.

In addition to the above configuration, the die casting sleeve according to the present invention has
``The inner cylinder has a steel layer formed of steel at least on the periphery of the pouring hole''.

Conventionally, sleeves that are used with their axial direction substantially horizontal have a problem in that the rear end of the cylindrical portion, which is the end on the side where the pouring hole is provided and into which the plunger tip is inserted, is deformed so as to warp upward. there were. If the rear end of the cylindrical portion warps up, there is a problem that "galling resistance" occurs in which the plunger tip bites into the upper portion of the inner surface.

Such deformation in which the rear end of the cylindrical portion warps upward is considered to occur as follows. That is, when hot molten metal is supplied from the pouring hole, the hot water receiving area becomes very hot. When the molten metal is supplied from the pouring hole, the liquid level of the molten metal does not reach the upper part of the inner surface of the inner cylinder, so the peripheral edge of the pouring hole does not become very hot. As a result, the hot water receiving region, which has reached a very high temperature, expands greatly in the axial direction of the cylindrical portion, while the peripheral edge portion of the pouring hole that faces the pouring hole has a small degree of thermal expansion and expands in the axial direction. Since the sleeve does not extend so much, the end of the sleeve on the pouring hole side deforms so as to warp upward.

In the sleeve of the present invention, at least the hot water receiving portion is made of the TC composite material as described above. The TC composite material is also a material with a small coefficient of thermal expansion. Therefore, in this configuration, the peripheral portion of the pouring hole, which is the portion facing the hot water receiving area and is the portion that does not reach a very high temperature, is made of steel having a higher thermal conductivity than the TC composite material. As a result, the thermal expansion in the hot water receiving area and the thermal expansion in the peripheral edge portion of the pouring hole can be balanced, and deformation such that the end portion on the pouring hole side warps upward can be suppressed.

In addition to the above configuration, the die casting sleeve according to the present invention has
"The inner cylinder has a composite material layer formed of the composite material over the entire length of the cylinder " . In addition, in the die-casting sleeve according to the present invention, "the height of the boundary between the steel layer and the composite material layer gradually increases from the rear end of the tubular portion toward the front end of the tubular portion." be.

In this configuration, the entire portion that comes into contact with the molten metal supplied from the pouring hole into the sleeve is made of a TC composite material with low thermal conductivity until the molten metal is injected into the cavity. Therefore, the heat retention of the sleeve is high, and it is possible to more effectively suppress the generation of solidified pieces due to the temperature drop of the molten metal.

In addition to the above configuration, the die casting sleeve according to the present invention has
It can be said that "the cooling device is provided at a position deviated to one side from a vertical line drawn from the center of the pouring hole in a cross section perpendicular to the central axis of the cylindrical portion".

Conventionally, it has been thought that the portion of the inner surface of the sleeve that becomes hot due to the supply of molten metal is directly below the pouring hole. On the other hand, as a result of careful analysis of the damaged portion of the sleeve, the present inventors found that the damaged portion was not only directly below the pouring hole, but was biased to one side from the vertical line drawn from the center of the pouring hole. I found that it reached the position. The reason for this is that, as will be described in detail later, in general die casting equipment, the ladle that supplies molten metal to the pouring hole is subject to mechanical restrictions, so that the molten metal is poured from diagonally above the pouring hole. thought to be supplied.

In this configuration, the cooling device provided in the outer cylinder can cool the portion that receives the molten metal supplied obliquely from above to the pouring hole by the ladle and becomes hot. As a result, the action of indirectly cooling the inner cylinder by cooling the outer cylinder can be exhibited more effectively.

As described above, according to the present invention, there is provided a die casting sleeve that has a long service life even when used under conditions in which a large amount of molten metal is supplied or a condition in which the time interval between molten metal supply is short. be able to.

(a) is a cross-sectional view of the sleeve of the first embodiment cut at the center in the direction of the central axis, and (b) is a cross-sectional view taken along the line AA. (a) is a graph comparing the temperature change of the inner surface of the inner cylinder of the hot water receiving region of the sleeve of the first embodiment with and without cooling; FIG. 4 is a graph comparing temperature changes on the inner surface of a region with and without cooling; FIG. 5 is a graph comparing the cooling effect between the inner surface and the inside of the inner cylinder of the hot water receiving area using the sleeve of the first embodiment. FIG. 4 is a graph comparing the temperature change accompanying repeated supply and discharge of molten metal with and without cooling using the sleeve of the first embodiment. FIG. 1 is a configuration diagram of a main part of a general die casting machine; FIG. FIG. 4 is a diagram schematically showing supply of molten metal from a ladle to a sleeve in a typical die casting machine; FIG. 4 is a cross-sectional view of the sleeve of the second embodiment cut at the center in the direction of the central axis; It is sectional drawing which cut the sleeve of the modification at the center in the direction of a central axis. 1 is a graph of hot mechanical strength of steel and TC composites;

Specific embodiments will be described below with reference to the drawings. The sleeve S1 of the first embodiment is a reference example, and the sleeve S1b of the second embodiment and the sleeve S1c of its modification are embodiments of the present invention. The description that follows is a description of an embodiment of the present invention. First, the sleeve S1 of the first embodiment will be explained. The sleeve S1 has a cylindrical tubular portion 1 and a pouring hole 30 penetrating a part of the side peripheral wall of the tubular portion 1 . The sleeve S1 is supported in the cold chamber die casting apparatus 100 with the central axis X of the cylindrical portion 1 substantially horizontal and the pouring hole 30 open upward. A cylindrical front end E1 of the sleeve S1 communicates with a cavity 110 formed between a fixed mold 111 and a movable mold 112, and a plunger tip 70 enters from a cylindrical rear end E2. Molten metal stored in a holding furnace is supplied to the pouring hole 30 via a ladle 130 .

The cylindrical portion 1 of the sleeve S1 has an outer cylinder 20 and an inner cylinder 10 fitted into the outer cylinder 20 . The hot water receiving region is the region below the pouring hole 30 in the tubular portion 1 . At least in the hot water receiving region, the inner cylinder 10 is made of a TC composite material (a sintered body of a composite material of titanium or a titanium alloy and ceramics), but in the first embodiment, the inner cylinder including the hot water receiving region 10 is made entirely of TC composite material. A TC composite material is manufactured by powder metallurgy, and can be obtained by firing a compact formed from a raw material mixture of titanium powder, silicon carbide powder, and nickel powder in a non-oxidizing atmosphere.

Here, the molten metal receiving region is a region that becomes hot when molten metal is poured from the pouring hole 30. As shown in FIG. The range L from the end E2 to twice the diameter of the pouring hole 30 can be set, and as shown in FIG. It can be defined as a range R1 indicated by circular arcs with a central angle α of 60 degrees toward both sides from the vertical line Z that has been lowered.

A cooling device 40 is provided on the outer cylinder 20 in this hot water receiving area. Specifically, the cooling device 40 has a double pipe structure pipe 41 , and the cooling medium supplied from the supply port 45 flows through the pipe 41 and is discharged from the discharge port 46 . In the hot water receiving area, the outer cylinder 20 is provided with an elongated insertion hole 25 parallel to the central axis X and opening at the rear end E2 of the cylinder. When the pipe 41 of the cooling device 40 is inserted into the insertion hole 25 , the cooling medium flowing through the pipe 41 exchanges heat with the hot outer cylinder 20 , thereby cooling the outer cylinder 20 and indirectly cooling the inner cylinder 10 . is cooled.

Water can be used as the cooling medium. Also, the configuration of the cooling device 40 is not limited to the one using the double pipe as described above. For example, a U-shaped pipe can be arranged inside the outer cylinder, and one end of the pipe can be used as a supply port and the other end can be used as a discharge port and opened in the end face or side wall of the outer cylinder. Further, a water-cooling jacket type cooling device may be attached to the outer cylinder 20 to cool the outer cylinder 20 from the outer surface side.

Here, the position where the cooling device 40 is provided on the outer cylinder 20 in the hot water receiving region is not directly below the pouring hole 30 in this embodiment, but is biased to one side from the vertical line Z drawn from the center of the pouring hole 30. position. This is because the portion of the inner surface of the cylindrical portion that is damaged by supplying the molten metal to the sleeve is not only directly below the pouring hole, as those skilled in the art have thought so far, but it extends to a position biased to one side. It was found that there was

The reason for this is that, as shown in FIG. It is conceivable that it is in the vicinity of the frame 122 or the like that supports the driving device (not shown) for the rotation on the stationary platen 121 . As a result, a device (not shown) for moving the ladle 130 for pouring the molten metal into the pouring hole 30 interferes with the fixed plate 121 and the frame 122, so the ladle 130 is moved to just above the pouring hole 30. As schematically shown in FIG. 6, the molten metal is poured obliquely from above into the pouring hole 30 by tilting the ladle 130 . As a result, the inner surface of the cylindrical portion 1 reaches the highest temperature not directly below the pouring hole 30, but at a portion deviated to one side from the vertical line Z, and is easily damaged.

Therefore, in this embodiment, as shown in FIG. The position of the cooling device 40 is set so that the angle β formed with the vertical line Z drawn from the center is 0 to 60 degrees on one side. It is more desirable to set the center line of the cooling device 40 in the range R2 in which the angle β is 10 degrees to 60 degrees to one side. A plurality of cooling devices 40 can be provided for one sleeve.

In practice, molten metal (aluminum) at 700° C. was supplied from the pouring hole 30 while water was circulated at a flow rate of 1 liter per minute to one cooling device 40 provided at a position where the angle β was 10 degrees. Fig. 2(a) shows the test results of measuring the temperature of the inner surface of the inner cylinder 10 in the hot water receiving area of the sleeve S1 with a thermocouple. For comparison, the sleeve S1 having the same structure in which the inner cylinder 10 is made of a TC composite material, but the cooling device 40 is not supplied with water, the temperature at the same measurement point is measured. (a) is also shown.

For comparison, a cooling device 40 having the same configuration as that of the sleeve S1 is provided at the same location as the sleeve S1 for a conventional sleeve whose cylindrical portion is entirely made of steel (SKD61) instead of having a double structure. FIG. 2B shows the results of measuring the temperature change at the same measurement point when water is circulated in the cooling device 40 and the temperature change at the same measurement point when water is not circulated in the cooling device 40.

As can be seen from FIG. 2(b), in the case of the conventional sleeve whose cylindrical portion is entirely made of steel, by cooling the hot water receiving area, the temperature at the measurement point rises to about 150 in a short time of about 2 seconds. °C, and the temperature drop is faster than without cooling. Such a rapid temperature drop may be able to suppress damage to the cylinder, but the temperature of the molten metal also drops rapidly, and the formation of solidified flakes may degrade the quality of the molded product. Conceivable.

On the other hand, as can be seen from FIG. 2(a), in the case of the sleeve S1 whose inner cylinder 10 is formed of the TC composite material, even when it is cooled by the cooling device 40, it is not cooled. However, there is no difference in the temperature change at the measurement points. SKD61 has a high thermal conductivity of 35.6 W/mK, whereas the TC composite material has a very low thermal conductivity of 7.4 W/mK. This is thought to be because the temperature of the inner surface of the core is not lowered.

Similarly, using the sleeve S1 of the example, a test comparing the cooling effect of the cooling device 40 on the inner surface of the inner cylinder 10 and the inside of the inner cylinder 10 was conducted on a laboratory scale. The temperature was measured on the inner surface of the inner cylinder 10 on the vertical line Z and on the same vertical line Z on the inside at a depth of 1 mm from the inner surface. The results are shown in FIG. Molten metal (aluminum) at 700° C. is supplied from the pouring hole 30 on the inner surface of the inner cylinder 10 while water is circulated through the cooling device 40 for cooling (cooling conditions are different from those in FIG. 2( a )). There is almost no difference in temperature between the case (solid line A) and the case (dashed line B) where molten metal is supplied under the same conditions without circulating water in the cooling device 40 . This is because, as described above with reference to FIG. 2(a), in the sleeve S1 in which the inner cylinder 10 is formed of the TC composite material, even if the outer cylinder 20 is cooled, the temperature of the inner surface of the inner cylinder 10 does not reach the temperature. This indicates that it will not be lowered. On the other hand, inside the inner cylinder 10, when molten metal is supplied under the same conditions while cooling by circulating water in the cooling device 40 (double-dot chain line D), the same conditions are obtained without circulating water in the cooling device 40. The temperature is much lower than when the molten metal is supplied at (thick solid line C). From this, it can be seen that the inside of the inner cylinder 10 can be effectively cooled by cooling the outer cylinder 20 with the cooling device 40 without lowering the temperature of the inner surface of the inner cylinder 10 . In particular, the ability to effectively cool the inside of the inner cylinder 10 without lowering the temperature of the inner surface is highly significant, even though the inside is extremely shallow, 1 mm from the inner surface of the inner cylinder 10 .

Furthermore, under the same conditions as the test described above with reference to FIG. 3, the operation of discharging the molten metal supplied to the sleeve S1 and supplying the molten metal again was repeated to measure the internal temperature at a depth of 1 mm from the inner surface. did. As a result, as shown in FIG. 4, when water is not passed through the cooling device 40, the temperature rises to 500° C., which causes a decrease in the mechanical strength of the TC composite material. In the case of cooling by circulating water through, the temperature rise could be suppressed to a temperature lower by about 100°C.

Considering the test results described with reference to FIGS. 2 to 4, at least in the hot water receiving area, the material of the inner cylinder 10 is made of TC composite material, and the outer cylinder 20 is cooled by the cooling device 40 in the hot water receiving area. That is, by indirectly cooling the inner cylinder 10 formed of a TC composite material having a low thermal conductivity from the outside, the TC composite material can be cooled to the extent that the temperature of the molten metal does not decrease, and solidified pieces It was thought that damage to the inner cylinder could be effectively suppressed while suppressing the generation of When we performed aluminum die casting at an actual manufacturing site, we found that even under conditions in which the amount of molten metal supplied was increased or under conditions in which the time intervals during which the molten metal was supplied were shortened, the We were able to achieve a service life eight times longer than that of conventional products without aluminum sticking to the surface or peeling of the inner surface.

Next, the sleeve S1b of the second embodiment will be explained using FIG. Configurations common to the sleeve S1 of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. The sleeve S1b differs from the sleeve S1 in that the inner cylinder 10 comprises a composite material layer 11 made of a TC composite material and a steel layer 12 made of steel. The composite material layer 11 extends over the entire length of the cylindrical portion 1 in the direction of the central axis X. As shown in FIG. Further, the height of the boundary between the composite material layer 11 and the steel layer 12 is provided so as to gradually increase from the tubular portion rear end E2 toward the tubular portion front end E1. In addition, in this embodiment, SKD61 is used as steel.

More specifically, the height of the boundary at the rear end E2 of the inner cylinder 10 is 1/4 to 1/2 times the outer diameter of the inner cylinder 10, and The height of the boundary is 1/2 to 3/4 times the outer diameter of the inner cylinder 10, and the height of the boundary increases linearly from the rear end E2 of the tubular portion toward the front end E1 of the tubular portion.

The coefficient of thermal expansion of steel (SKD61) is 10.7×10 ⁻⁶ /° C., whereas the coefficient of thermal expansion of TC composites is 7.4×10 ⁻⁶ /° C., which is smaller than steel. In the second embodiment, the portion of the inner cylinder 10 that contacts the molten metal, that is, the molten metal receiving area that receives the molten metal supplied from the pouring hole 30, and the front end E1 of the cylindrical portion as the plunger tip 70 advances. Substantially the entire portion in contact with the moving molten metal is made of a TC composite material with a low coefficient of thermal expansion. A peripheral portion of the pouring hole 30, which is a portion of the sleeve S1b facing the hot water receiving area and does not reach a high temperature, is made of steel having a larger coefficient of thermal expansion than the TC composite material.

As a result, compared to the case where the entire inner cylinder 10 is made of the same material, the amount of thermal expansion between the molten metal receiving region and the periphery of the pouring hole 30 when in contact with the molten metal is reduced. The difference is small, and it is possible to approach a state in which the thermal expansions in both regions are balanced. In addition, by cooling the outer cylinder 20 with the cooling device 40, the thermal expansion of the inner cylinder 10 in the hot water receiving area is further reduced, and the difference in thermal expansion from the peripheral edge of the pouring hole 30 is further reduced. Therefore, due to the difference in the magnitude of thermal expansion between the two regions when the molten metal is supplied, the rear end E2 of the cylindrical portion can be prevented from being warped and deformed. It is possible to reduce the possibility of occurrence of "galling resistance" in which the plunger tip 70 bites into the upper portion of the inner surface of the cylindrical portion.

In addition, in the sleeve S1b of the second embodiment, since the composite material layer 11 is provided over the entire length of the cylindrical portion 1 in the direction of the central axis X, the portion of the cylindrical portion 1 that contacts the molten metal is It is made of a material with low thermal conductivity as a whole and has high heat retention. Therefore, the risk of the temperature of the molten metal dropping in the sleeve before reaching the cavity is reduced, and a high-quality product can be molded without solidified pieces.

In the sleeve S1b, the height of the boundary between the steel layer 12 and the composite material layer 11 in the inner cylinder 10 rises from the rear end E2 of the tubular portion toward the front end E1 of the tubular portion. As the plunger tip 70 advances, the liquid level of the molten metal supplied from the pouring hole 30 into the sleeve S1b rises toward the cylindrical front end E1. In the second embodiment, the height of the boundary between both layers is raised from the rear end E2 of the tubular portion toward the front end E1 of the tubular portion in accordance with such a rise in the liquid level of the molten metal. Therefore, the portion that comes into contact with the molten metal is made entirely of a material with low thermal conductivity, which effectively reduces the possibility that the temperature of the molten metal drops in the sleeve and solidified pieces are generated. there is In addition, since the portion that comes into contact with the molten metal is entirely made of a TC composite material with a small coefficient of thermal expansion, elongation due to thermal expansion is better suppressed, and the rear end E2 of the cylindrical portion warps upward. Deformation is suppressed more effectively.

As described above, according to the sleeves S1 and S1b of the present embodiment, the inner cylinder 10 is made of a TC composite material having a low thermal conductivity at least in the hot water receiving region where the temperature is high when the molten metal is supplied. By cooling the outer cylinder 20 in the hot water receiving region by the cooling device 40, the inner cylinder 10 can be indirectly cooled to the extent that the temperature of the molten metal does not decrease, and the inner cylinder 10 can be cooled while suppressing the generation of solidified pieces. damage to the sleeve and extend the service life of the sleeve.

In addition, according to the sleeve S1b of the second embodiment, the hot water receiving area is made of a TC composite material with a small coefficient of thermal expansion, while the peripheral edge of the pouring hole 30 is made of steel. It is possible to effectively prevent deformation in which E2 is warped upward.

As described above, the present invention has been described with reference to preferred embodiments, but the present invention is not limited to the above embodiments, and as shown below, various improvements can be made without departing from the scope of the present invention. and design changes are possible.

For example, a surface treatment layer can be provided on the inner surface of the inner cylinder 10 by surface treatment such as nitriding treatment, carbonization treatment, and boron treatment.

In the above description, silicon carbide (SiC) was exemplified as a raw material of the TC composite material, but it is not limited to this, and nitride ceramics such as Si ₃ N ₄ , TiN, BN, and ALN, TiC, Carbide ceramics such as _B4C and _{CrC2 ,} boride ceramics such as _ZrB2 and _TiB2 , oxide ceramics such as _{Cr2O3 , TiO2} , _ZrO2 , MgO and _Y2O3 , and sialon can be used singly or in combination.

Furthermore, in the embodiment in which the inner cylinder 10 is formed of the steel layer 12 and the composite material layer 11, the lengths of the steel layer 12 and the composite material layer 11 extend over the entire length of the inner cylinder 10 in the axial direction. and the height of the boundary between the two layers gradually increases toward the front end E1 of the cylindrical portion, but the length of the steel layer 12 in the axial direction is greater than the total length N1 of the inner cylinder 10 in the axial direction. A shorter configuration is also possible. Specifically, as shown in FIG. 8, the height of the boundary between the two layers is 1/4 to 1/2 times the outer diameter of the inner cylinder 10 at the rear end E2 of the cylinder portion of the inner cylinder 10. The height of the boundary gradually increases toward the front end E1 of the tubular portion, and at a position where the length in the axial direction from the front end E1 of the tubular portion of the inner tube 10 is N2, the entire side peripheral wall of the inner tube 10 is made of TC composite material. The sleeve S1c can be made up of only the composite material layer 11 formed in the above. Here, the length N2 is such that the maximum length (N1-N2) of the steel layer 12 in the axial direction is 3/2 to 3 times the length of the pouring hole 30 in the axial direction of the inner cylinder 10. can be set to

With the sleeve S1c having such a configuration, it is possible to obtain the same effects as those described above for the sleeves S1 and S1b. In addition, in the sleeve S1c, a range close to the necessary minimum including the periphery of the pouring hole 30, which is a portion where thermal expansion should be balanced with the hot water receiving region that becomes hot due to the molten metal supplied from the pouring hole 30 is made of steel, which has a higher coefficient of thermal expansion than the TC composite material. As a result, the rear end E2 side of the cylindrical portion is effectively prevented from being warped upward, while the remaining portion is surrounded by a TC composite material layer having a low thermal conductivity, thereby further effectively suppressing a decrease in the temperature of the molten metal. can do.

1 cylinder part 10 inner cylinder 11 composite material layer 12 steel layer 20 outer cylinder 30 pouring hole 40 cooling device 70 plunger tip E1 cylinder front end E2 cylinder rear end S1, S1b, S1c sleeve (sleeve for die casting)

Claims (2)

Equipped with a cylindrical cylindrical portion and a pouring hole that penetrates a part of the side peripheral wall of the cylindrical portion, the cylindrical portion is opened in a state where the central axis of the cylindrical portion is substantially horizontal and the pouring hole is opened upward. A die-casting sleeve having a front end communicating with a cavity and allowing a plunger tip to enter from the rear end of a cylindrical portion,
The cylindrical portion has an outer cylinder and an inner cylinder fitted into the outer cylinder,
In the cylindrical part, the inner cylinder has a composite material layer formed of a sintered body of a composite material of titanium or a titanium alloy and ceramics over the entire length including the hot water receiving area below the pouring hole. Along with being
A cooling device is provided on the outer cylinder in the hot water receiving region ,
The inner cylinder has a steel layer formed of steel at least on the periphery of the pouring hole,
The height of the boundary between the steel layer and the composite material layer gradually increases from the rear end of the tubular portion toward the front end of the tubular portion.
A die-casting sleeve characterized by: The cooling device is provided at a position deviated to one side from a vertical line drawn from the center of the pouring hole in a cross section perpendicular to the central axis of the tubular portion. The die casting sleeve according to claim 1.

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