JPH0261871B2 - - Google Patents

Description

[Detailed Description of the Invention] A. Object of the Invention (1) Industrial Field of Application The present invention relates to a method for casting a light alloy cylinder block material, in particular a method for casting a cylinder sleeve made of cast iron and enclosing the cylinder sleeve. A light alloy cylinder block material consisting of a cylinder barrel on which a water jacket is formed and a crankcase connected to the cylinder barrel is connected to a first cavity for forming the cylinder barrel and a second cavity for forming the crankcase, which communicate with each other. The present invention relates to a casting method using a mold having the following.

(2) Prior Art Conventionally, when casting this type of cylinder block material, a mold was used in which a crankcase molding cavity was disposed at the bottom and a cylinder barrel molding cavity was disposed at the top. A cylinder sleeve and a sand core for forming a water jacket are installed in the crankcase, and molten metal is injected from the bottom of the crankcase forming cavity.

(3) Problems to be Solved by the Invention However, when the mold having the above configuration is used, the filling of the molten metal in the cavity for forming the cylinder barrel is delayed, the temperature of the molten metal decreases, and the adhesion between the light alloy and the cylinder sleeve deteriorates. The problem is that it gets worse.

An object of the present invention is to provide the casting method that can solve the above problems.

B. Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention provides a cylinder barrel in which a cast iron cylinder sleeve is cast and a water jacket surrounding the cylinder sleeve is formed. A light alloy cylinder block material consisting of a cylinder barrel and a crankcase connected to the cylinder barrel is cast using a mold having a first cavity for forming the cylinder barrel and a second cavity for forming the crankcase that communicate with each other. In the method for casting a light alloy cylinder block material, the first cavity of the mold is installed such that the second cavity is located above the first cavity. The method includes at least a step of disposing a sand core, and a step of filling the first and second cavities with a molten light alloy under pressure, and when filling the molten metal under pressure, the inside of the first cavity becomes The present invention is characterized in that the molten metal is introduced into both cavities from the lower part of the first cavity so that the molten metal is filled before the second cavity.

(2) Function The molten metal is introduced into both cavities from the lower part of the first cavity for forming the cylinder barrel, and the inside of the first cavity becomes the second cavity for forming the crankcase.
Because it is filled with molten metal before the inside of the cavity,
Coupled with the heat retention effect of the sand core, a drop in the temperature of the molten metal in the first cavity is effectively prevented, thereby improving the adhesion between the light alloy and the cylinder sleeve.

(3) Embodiment Figures 1 to 3 show a Siamese-type cylinder block S made of a fiber-reinforced aluminum alloy made of a material obtained according to the present invention, in which a plurality of cylinder blocks S are arranged in series, four in the illustrated example. A Siamese cylinder barrel 1 formed by connecting cylinder barrels 1 ₁ to 1 ₄ with each other, an outer wall 2 surrounding the Siamese cylinder barrel 1, and a crank connected to the lower edge of the Siamese cylinder barrel 1 and the outer wall 2. It consists of Case 3. A cast iron cylinder sleeve Cs defining a cylinder bore 4 is cast into each cylinder barrel 1 ₁ to 1 ₄ .

A water jacket 6 is formed between the Siamese cylinder barrel 1 and the outer wall portion 2, and the outer periphery of the Siamese cylinder barrel 1 is exposed to the water jacket 6. At the end of the water jacket 6 on the cylinder head side, the Siamese cylinder barrel 1 and the outer wall 2 are partially connected by a plurality of reinforcing deck parts 8, and the adjacent reinforcing deck parts 8 communicate with each other to the cylinder head side. Functions as mouth 7. As a result, the cylinder block S is constructed into a closed deck type.

5 to 8 show a casting device used in the practice of the present invention to cast the cylinder block material Sm shown in FIG. 4, and the device is equipped with a mold M as a mold. An upper mold 9 that can be raised and lowered, and first and second side molds 10 ₁ and 10 ₂ that are disposed below the upper mold 9 and are divided into left and right halves in FIGS. 5 and 6.
In FIG. 7, it is composed of third and fourth side molds 10 ₃ and 10 ₄ divided into left and right halves, and a lower mold 11 on which each of the side molds 10 ₁ to 10 ₄ is slidably placed.

As clearly shown in FIGS. 7 and 8, the lower mold 11 includes a sump 12 that receives molten aluminum alloy from a melting furnace (not shown), a hot water cylinder 13 communicating with the sump 12, and a hot water supply cylinder 13 that communicates with the sump 12. A plunger 14 that slides on the hot water supply cylinder 13 and a pair of runners 15 that branch into two from the hot water reservoir 12 and extend substantially parallel to each other are provided.

A first cavity C ₁ for molding the Siamese cylinder barrel 1 and outer wall 2 is defined by the upper surface between the two runners 15 in the lower mold 11 and the lower half of each side mold 10 ₁ to _{10 4} . be done. The lower portions of both sides of the first cavity C ₁ communicate with both runners 15 via a plurality of weirs 16 . A large number of recesses 17 used to form the communication openings 7 are provided on the outer peripheral portion of the upper surface of the lower mold 11 facing the first cavity C ₁ .

The upper mold 9 has a molding block 18 projecting downward, and the molding block 18 is connected to each side mold 10 ₁ to 10 _{4 .}
A second cavity _C2 for forming the crankcase 3 is defined in cooperation with the upper half of the crankcase. The lower end of the cavity _C2 communicates with the upper end of the first cavity _C1 .

The molding block 18 includes four tall semi-cylindrical first molding parts ₁₈₁ formed at predetermined intervals;
Between the adjacent first molded parts 18 ₁ and both the outermost first molded parts 18
It consists _of a convex second molding part ₁₈₂ located outside the molding part 181, and each first molding part ₁₈₁ is for molding a rotation space 20 for the crank pin and crank arm (Figs. 2 and 3). The second molded part 18 ₂ is used for the bearing holder 2 of the crank journal.
1 (Figures 2 and 3).

Both runners 15 have a runner tip 15a from the water reservoir 12 side.
The bottom surface of the runner 15 is formed in the shape of several steps ascending from the trough portion 12 side so that the cross-sectional area gradually decreases toward the bottom. Each rising portion 15c connected to each step portion 15b is formed diagonally so that the molten metal can be smoothly guided to each weir 16.

When the cross-sectional area of the runner 15 is reduced in stages in this way, a large amount of molten metal is injected into the first cavity C1 through the weir ₁₆ at a slow speed in the large cross-sectional area, and a small amount is injected in the small cross-sectional area. of the molten metal can be injected into the first cavity C ₁ through the weir 16 at _a high speed.
Inside, the molten metal level rises almost horizontally from the lower ends of both sides over its entire length, and the molten metal rises in the cavity.
There is no turbulence within C ₁ , and gases such as air are prevented from being drawn into the molten metal, thereby avoiding the formation of cavities. Further, since the molten metal injection work is performed efficiently, casting efficiency can be improved.

A mandrel 19 having a columnar shape and inserted into the cylinder sleeve Cs is protrudingly provided on the lower surface of each first molded part ₁₈₁ ,
A positioning protrusion 22 is protrudingly provided on the lower mold 11 so as to face the lower end surface of the mandrel 19 and into which the lower end of the cylinder sleeve Cs is fitted. A recess 23 is formed in the center of the positioning protrusion 22, and the recess 23
It is designed to fit into the convex portion 19a of No.9. In addition, the two first molded parts 18 ₁ located on both sides have
Lower mold 1 is positioned on both sides of positioning protrusion 22.
A through hole 24 is formed through the through hole 1, and a pair of temporary installation pins 25 are slidably fitted into the through hole 24, respectively. These temporary installation pins 25 are used for temporary installation of a sand core for forming a water jacket, which will be described later. The lower ends of both temporary installation pins 25 are fixed to a mounting plate 26 arranged in the empty space of the lower mold 11. Two support rods 27 are inserted through the mounting plate 26, and a coil spring 28 is compressed between the lower part of each support rod 27 and the lower surface of the mounting plate 26. When the mold is opened, the mounting plate 26 receives the elastic force of each coil spring 28 and rises until it comes into contact with the stopper 27a at the tip of each support rod 27, so that the tips of each temporary installation pin 25 protrude from the upper surface of the lower mold. There is. A recess 25a that engages with the lower edge of the sand core is formed on the tip end surface of each temporary installation pin 25.

A through hole 29 is formed in the lower mold 11 at a bisecting position between the two through holes 24, and an operating pin 30 whose lower end is fixed to the mounting plate 26 is slid into the through hole 29. When the mold is opened, the tip of the operating pin 30 protrudes into the recess 23, and when the mold is closed, it is pushed down by the mandrel 19, thereby causing both temporary installation pins 25 to be retracted from the upper surface of the lower mold 11.

The first in the first and second side molds 10 ₁ , 10 ₂
Core holders 31 for actually installing sand cores are provided at two locations in the center of the wall defining the cavity _C1 . Each core holder 31 includes an engagement hole 31a for positioning the sand core, and a holding surface 31b formed on the outer periphery of the opening thereof to sandwich the sand core.

A plurality of third cavities C ₃ are formed at the bases on both sides of each first molding part 18 ₁ in the upper mold 9 to communicate with the second cavity C ₂ and allow the molten metal to overflow. A gas vent hole 32 communicating with the cavity _C3 is formed.

Closing pins 34 are loosely inserted into these gas vent holes 32, and the upper ends of these closing pins 34 are fixed to a mounting plate 36 disposed above the upper die 9.

A small diameter portion 32a of the gas vent hole 32, which extends upward over a predetermined length from the end communicating with the cavity _C3 , is fitted with the lower end of the closing pin 34 to close the third cavity _C3 . ing.

The hydraulic cylinder 3 is placed between the upper surface of the upper die 9 and the mounting plate 36.
7 is interposed, and the mounting plate 36 is raised and lowered by the operation of the hydraulic cylinder 37, and the small diameter portion 32a is opened and closed by each closing pin 34. 38 is a guide rod for the mounting plate 36.

9 and 10 show a sand core 39 for a water jacket, and the sand core 39 has four cylindrical parts 40 1 to ₄₀ corresponding to the four cylinder barrels 1 ₁ to 1 ₄ of the cylinder block S. A core main body 41 which is provided with 40 ₄ and lacks the surrounding walls where the adjacent ones overlap each other, a communication port 7 that communicates the water jacket with the water jacket of the cylinder head, and a reinforcing deck part 8.
To form a plurality of protrusions 42 protruding from the lower end surface of the core body 41, and two cylindrical portions 40 ₂ located in the middle on both outer surfaces of the core body 41 in the cylinder barrel arrangement direction. , 40 ₃ and baseboards 43 protruding from both outer surfaces of the base boards 40 3 . Each baseboard 4
3 is formed by a large diameter portion 43a that is integral with the core body 41, and a small diameter portion 43b that projects from the end surface thereof.

Next, the cylinder block material is made by the casting machine.
I will explain the casting work of Sm.

First, as shown in FIG. 5, the upper mold 9 is raised, and the opposing molds 10 ₁ , 10 ₂ ; 10 ₃ , 10 ₄
The molds are opened by moving them apart from each other. The hydraulic cylinder 37 on the upper mold 9 is operated to raise the closing pin 34 via the mounting plate 36, thereby opening the small diameter portion 32a of the gas vent hole 32. Furthermore, the plunger 14 in the hot water supply cylinder 12 is lowered.

The lower end of the cylinder sleeve Cs is fitted into each positioning protrusion 22 of the lower mold 11, and the cylinder sleeve Cs
is placed upright on the lower mold 11. As shown in FIGS. 5 and 10, each of the cylindrical parts 40 ₁ to 40 ₄ of the sand core 39 is loosely inserted into each cylinder sleeve Cs, and the cylindrical parts 4 on both sides are inserted loosely into each cylinder sleeve Cs.
0 ₁ , 40 ₄ lower edge to each temporary installation pin 25 of the lower mold 11
The sand core 39 is temporarily installed by engaging the recess 25a of the sand core 39. Each protrusion 42 of the sand core 39 is loosely inserted into each recess 17 of the lower mold 11, as shown in FIGS. 6 and 8.

As shown in FIG. 6, the two-sided molds 10 ₁ and 10 ₂ are moved a predetermined distance in the direction in which they approach each other,
Each core holder 31 and each baseboard 43 are engaged to make the sand core 3
9 books will be installed. That is, the sand core 39 is positioned by fitting the small diameter portion 43b of each skirting board 43 in the sand core 39 into the engagement hole 31a of each core receiver 31, and also aligning the cylinder barrel arrangement direction of each large diameter portion 43a. The sand core 39 is held between the holding surfaces 31b of each core holder 31 by abutting the end surfaces parallel to the sand core 39 against the holding surfaces 31b of each core holder 31. Further, the other double-sided molds 10 ₃ and 10 ₄ are also moved in the same manner.

Next, the upper mold 9 is lowered to perform mold clamping. With this mold clamping, each mandrel 19 is attached to each cylinder sleeve.
Inserted into Cs. Further, since the convex portion 19a of the mandrel 19 fits into the concave portion 23 of the lower die 11, the operating pin 3
0 is pushed down, each temporary installation pin 25 descends and is retracted from the upper surface of the lower mold 11.

730 to 740℃ from the melting furnace to the sump 12 of the lower mold 11
The plunger 14 is raised at a predetermined speed, and the molten metal is passed through the weir 16 from the two runners 15 to the first
From the bottom of both sides _of cavity C ₁
Then, the second cavity _C2 is filled under a predetermined pressure _P1 . Gas such as air in both cavities C ₁ and C ₂ is pushed up by the molten metal and escapes above the upper mold 9 through a gas vent hole 32 communicating with the third cavity C ₃ .

In this case, both runners 15 are the runners 15 and 15 as described above.
The bottom surface of the runner is formed in the shape of several steps ascending from the sump 12 side so that the cross-sectional area gradually decreases toward point a. The liquid is injected into the first cavity C ₁ through each weir 16 from the bottom on both sides almost uniformly over its entire length.

When the molten metal is completely injected into the third cavity C ₃ , the hydraulic cylinder 37 on the upper die 9 is operated to lower the mounting plate 36 , and the small-diameter hole communicating with the third cavity C ₃ is opened by the closing pin 34 . The part 32a is closed, and the plunger 14 is raised at a predetermined speed to maintain the molten metal under a high pressure _{p2 exceeding the pressure p1 to} completely solidify it, thereby densifying the structure of the aluminum alloy matrix. The strength can be improved.

Furthermore, the molten metal is introduced into the cavities C ₁ to _{C 3} from the lower part of the first cavity C ₁ , and the first cavity C ₁ is filled with the molten metal before the second cavity C ₂ is filled. Coupled with the heat retention effect of the sand core 39, a drop in the temperature of the molten metal in the first cavity _C1 is effectively prevented, and therefore the adhesion between the aluminum alloy and the cylinder sleeve Cs is improved. Further, the core metal 19 prevents deformation of each cylinder sleeve Cs due to the pressure of the molten metal.

Since the sand core 39 is held in an accurate position by the molds 10 ₁ and 10 ₂ on both sides through its baseboards 43, the sand core 39 is held in a precise position by the molds 10 1 and 10 2 on both sides, so that when pouring molten metal into the first cavity C ₁ and when pouring the molten metal into the first cavity C 1 , When the molten metal in ₁ is pressurized, the sand core 39 does not float or sag. Further, the end surface of the large diameter portion 43a of each baseboard 43 is the clamping surface 31 of the core receiver 31 in the double-sided types 10 ₁ and 10 _{2 .}
b, so that when the sand core 39 tends to swell, the deformation force is supported by each clamping surface 31b, which prevents the sand core 39 from deforming and causes the 4th circumference of each cylinder bore to expand. A Siamese cylinder barrel 1 having a uniform wall thickness is obtained.

When the mold is opened after the molten metal has solidified, the fourth
The cylinder block material Sm shown in the figure is obtained.

When the cylinder block material Sm is subjected to a grinding process to remove each projection 44 formed by the cooperation of each recess 17 and each projection 42 of the sand core 39, each communication port 7 and reinforcing deck portion 8 are formed. Further, by removing sand, a water jacket 6 is obtained, and the inner circumferential surface of each cylinder bore 4 is machined into a perfect circle, and further, by performing other predetermined processing, the cylinder block shown in Figs. 1 to 3 is obtained. S is obtained.

Note that it is possible to use a light alloy such as a magnesium alloy in addition to the aluminum alloy.

C. Effects of the Invention As described above, according to the present invention, there is provided a cylinder barrel in which a cast iron cylinder sleeve is cast, a water jacket surrounding the cylinder sleeve is formed, and a crankcase connected to the cylinder barrel. The light alloy cylinder block material is cast using a mold having a first cavity for forming the cylinder barrel and a second cavity for forming the crankcase that communicate with each other. In the casting method, the step of arranging the cylinder sleeve and the sand core for forming a water jacket in the first cavity of the mold, which is installed such that the second cavity is located above the first cavity; and filling the first and second cavities with a molten light alloy under pressure, and when the molten metal is pressurized and filled, the inside of the first cavity is filled with the second cavity.
so that it is filled with molten metal before the inside of the cavity.
Since the molten metal is introduced into both cavities from the lower part of the first cavity, when filling both cavities with the light alloy molten metal under pressure, the inside of the first cavity for forming the cylinder barrel is transferred into the second cavity for forming the crankcase. Therefore, together with the heat retention effect of the sand core, it is possible to effectively prevent the temperature of the molten metal from decreasing in the first cavity. A light alloy cylinder block material with good adhesion to the cylinder sleeve can be obtained.

[Brief explanation of the drawing]

1 to 3 show a Siamese type cylinder block made of the material obtained according to the present invention,
Fig. 1 is a perspective view seen from above, Fig. 2 is a sectional view taken along the line shown in Fig. 1, Fig. 2A is a sectional view taken along line a-a of Fig. 2, Fig. 3 is a perspective view seen from below, Fig. 4 is a perspective view from above of the Siamese type cylinder block material obtained by the present invention, FIG. 5 is a longitudinal sectional front view of the casting device when the mold is opened, and FIG. 6 is a longitudinal sectional front view of the casting device when the mold is closed. Fig. 7 is a sectional view taken along the line shown in Fig. 6, Fig. 8 is a sectional view taken taken along the line taken from Fig. 7, Fig. 9 is a perspective view of the sand core seen from below, and Fig. 10 is a sectional view taken along the line taken from Fig. 9.
The figure-line sectional view and FIG. 11 are graphs showing the relationship between molten metal pressure and time. C ₁ , C ₂ ... First and second cavities, Cs ... Cylinder sleeve, Sm ... Siamese type cylinder block material, 1 ₁ to 1 ₄ ... Cylinder barrel,
3...Crankcase, 6...Water jacket, 3
9...Sunako.

Claims (1)

[Claims] 1 Cylinder barrels 1 ₁ to 1 ₄ in which a cast iron cylinder sleeve Cs is cast and a water jacket 6 surrounding the cylinder sleeve Cs is formed.
A light alloy cylinder block material Sm consisting of a crankcase 3 connected to the cylinder barrels 1 ₁ to 1 ₄ is connected to a first cavity C 1 for forming the cylinder barrel and a second cavity C ₁ for forming the crankcase, which communicate with each other. In the casting method for a light alloy cylinder block material, the first cavity is cast using a mold M having a cavity _C2 .
The first cavity of the mold M is installed such that the second cavity _C2 is located above _C1 .
The method includes at least the step of disposing the cylinder sleeve Cs and the water jacket forming sand core 39 in C1, and the step of filling the first and second cavities _{C1 and C2} with molten light alloy under pressure. However, when filling the molten metal under pressure, both cavities C 1 and C are filled from the lower part of the first cavity C ₁ so that the first cavity C ₁ is filled with the molten metal before the second cavity C ₂ is filled with the _molten metal. _2. A method for casting a light alloy cylinder block material, characterized in that molten metal is introduced into the chamber.