JPS6338257B2 - - Google Patents

Description

Detailed Description of the Invention A. Object of the Invention (1) Industrial Field of Application The present invention provides an aluminum alloy cylinder in which a cast iron sleeve is cast around the cylinder barrel and a water jacket is provided around the outer periphery of the cylinder barrel. This invention relates to a method for manufacturing blocks.

(2) Prior Art Conventionally, the cylinder block has been manufactured by the following method.

That is, a cylinder sleeve and a collapsible core for a water jacket surrounding the cylinder sleeve are disposed in a mold cavity, and a cylinder block material is cast using molten aluminum alloy. Next, unnecessary parts such as weirs and runners are removed from the material, and the material is vibrated to cause the collapsible core to collapse and about half of it is removed from the material. The material is then heated at 350°C or above for about four hours to burn off the binder contained in the core and improve the disintegration of the remaining part of the core.

The above-mentioned heating significantly reduces the hardness of the aluminum alloy portion of the material, making it impossible to maintain sufficient hardness in the cylinder head joint surface, crank journal bearing holder, crankcase oil pan joint surface, etc. Therefore, the material is subjected to T6 treatment, in which the material is heated at approximately 500°C for approximately 2 hours, and then water-cooled to restore its hardness.

Furthermore, the material is vibrated to cause the remaining portion of the core to collapse and removed from the material, and then the material is deburred, and after inspection, the material is subjected to predetermined machining.

(3) Problems to be Solved by the Invention However, in the case of the conventional method, even though the hardness of the aluminum alloy part of the material can be improved by the T6 treatment, the cylinder sleeve is damaged during the water cooling step in the treatment. There is a problem in that uniform stress remains and a highly accurate cylinder block cannot be obtained.

Furthermore, since it involves two heating steps, it consumes a lot of energy and is uneconomical.

In view of the above, an object of the present invention is to provide a method capable of economically manufacturing a highly accurate cylinder block by removing the core at room temperature and performing heat treatment to the extent of removing distortion.

B. Structure of the Invention (1) Means for Solving the Problems The present invention provides a method of disposing the cylinder sleeve and a collapsible core for a water jacket surrounding the cylinder sleeve in the cavity of a mold, and using the molten aluminum alloy. a step of casting the cylinder block material; a step of collapsing the core at room temperature and removing it from the cylinder block material; a step of subjecting the cylinder block material to annealing; and a step of machining the cylinder block material. Process and;
It is characterized by using

(2) Effect When the core is disintegrated at room temperature and removed from the cylinder block material, the hardness of the aluminum alloy part of the material will not be reduced. Therefore, in order to restore the hardness of aluminum alloy parts,
T6 treatment is not required, and a highly accurate cylinder block can be obtained simply by annealing the material to remove distortion.

(3) Embodiment Figures 1 to 3 show a Siamese-type cylinder block S obtained according to the present invention, which consists of an aluminum alloy cylinder block body 2, a cast iron cylinder sleeve 3 cast into the body 2, and a cylinder block S made of aluminum alloy. It becomes more. The cylinder block body 2 includes a plurality of cylinder barrels 1 ₁ to 1 ₄ arranged in series, four cylinder barrels in the illustrated example.
It is composed of a Siamese cylinder barrel 1 which is connected to each other, an outer wall part 4 surrounding the Siamese cylinder barrel 1, and a crankcase 5 connected to the lower edge of the outer wall part 4, and each cylinder barrel 1 ₁ - The cylinder sleeves 3 are cast into the cylinders 1 _{and 4} , and each cylinder sleeve 3 forms a cylinder bore 3a.

A water jacket 6 is formed between the Siamese cylinder barrel 1 and the outer wall portion 4, 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 4 are partially connected by a plurality of reinforcing deck parts 8, and the adjacent reinforcing deck parts 8 have communication ports to the cylinder head side. 7
functions as As a result, the cylinder block S
is constructed as a closed deck type.

5 to 9 show a casting device for the cylinder block material Sm shown in FIG. 4, and the device is equipped with a mold M as a casting mold. The first and second side molds 1 are disposed below the mold 9 and are divided into left and right halves in FIGS. 5 and 6.
0 ₁ , 10 ₂ and the third and fourth side molds 10 ₃ , 10 ₄ divided into left and right halves in FIG.
₁ to 10 ₄ are slidably placed thereon.

A first cavity C ₁ is provided on the lower surface of the upper mold 9 for molding the Siamese cylinder barrel 1 and the outer wall portion 4 in cooperation with the upper half of each of the side molds 10 ₁ to 10 ₄ .
A mold clamping recess 12 is formed, and a mold clamping convex 13 that fits into the recess 12 is formed on each side of the mold 10.
₁ to 10 ₄ protrudingly provided on the upper surface.

As shown in FIGS. 7 and 8, the lower mold 11 includes a sump 14 that receives molten metal made of aluminum alloy from a melting furnace (not shown), and a hot water supply cylinder 15 that communicates with the sump 14. The hot water cylinder 15
The plunger 16 slides into the plunger 16, and the first cavity C1 branches into two parts from the sump 14 in the longitudinal direction of the first cavity _C1 .
In addition, a pair of runners 17 are provided that extend over approximately the same length. Also, the lower mold 11 has both runners 17
It has a molding block 18 that protrudes upward between the two molds 10 ₁ to 10 _{4 .}
A second cavity _C2 for forming the crankcase 5 is defined in cooperation with the lower half of the crankcase. The upper end of the cavity C ₂ communicates with the first cavity C ₁ , and the lower ends on both sides have a plurality of weirs 19 connected to both runners 17 .
communicate via.

The molding block 18 includes four tall semi-cylindrical first molding parts ₁₈₁ formed at predetermined intervals;
Between adjacent first molded parts 18 ₁ and both outermost first molded parts 18 1
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 a crank pin and a 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). Each weir 19 is provided corresponding to the second molding part 18 ₂ so that the large volume portion of the second cavity C ₂ is quickly filled with molten metal.

The runners 17 are arranged such that the cross-sectional area of both runners 17 gradually decreases from the water reservoir 14 side toward the runner tip 17a.
The bottom surface of 7 is formed in the shape of several steps ascending from the trough portion 14 side. Each rising portion 17c connected to each step portion 17b is formed diagonally so that the molten metal can be smoothly guided to each weir 19.

When the cross-sectional area of the runner 17 is reduced stepwise in this way, a large amount of molten metal is filled into the second cavity _C2 through the weir 19 at a slow speed in the large cross-sectional area, and a small amount is filled in the small cross-sectional area. can be filled into the second cavity C ₂ through the weir 19 at a high speed, so that the cavity C ₂
Inside the cavity, the melt level rises almost evenly over the entire length from the lower ends of both sides, so the molten metal does not cause turbulent flow within the cavity _C2 , and gases such as air are prevented from being drawn into the molten metal. nests can be avoided. Further, since the molten metal filling operation is performed efficiently, casting efficiency can be improved.

As shown in FIGS. 5 and 6, each first molding section 18 ₁
A positioning protrusion 22 that fits into the inner circumferential surface of the cast iron cylinder sleeve 3 is protruded from the top surface of the cylinder sleeve 3, and a recess 23 is formed in the center of the positioning protrusion 22. In addition, two first molded parts 18 ₁ located on both sides
A through hole 24 passing through the first molded part 18 ₁ is formed on both sides of the positioning protrusion 22 , and a pair of temporary installation pins 25 are slid into each of the through holes 24 , and the temporary installation pins 25 will be described later. Used for temporary installation of collapsible cores for water jackets. The lower ends of both temporary installation pins 25 are fixed to a mounting plate 26 disposed below the forming block 18. Two support rods 27 are inserted through the mounting plate 26, and the lower part of each support rod 27 and the mounting plate 26 are inserted into the mounting plate 26.
A coil spring 28 is compressed between the lower surface of the holder and the lower surface of the holder.
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 tip of each temporary installation pin 25 is attached to the first molded part 18 ₁ It protrudes from the top. A recess 25a that engages with the lower edge of the core is formed on the tip end surface of each temporary installation pin 25.

Further, in the two first molded parts 18 ₁ located on both sides, a through hole 29 is formed that penetrates the first molded part 18 ₁ at a bisecting position between both through holes 24 , and the lower end is inserted into the through hole 29 . An operating pin 30 fixed to the mounting plate 26 is slid together. 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 a diameter expanding mechanism, which will be described later, so that both temporary pins 25 are retracted from the top surface of the first molding section ₁₈₁ . It's summery.

The first in the first and second side molds 10 ₁ , 10 ₂
In the central part of the wall defining the cavity _C1 , two core holders 31 are provided for permanently installing the core. Each core receiver 31 includes an engagement hole 31a for positioning the core, and a clamping surface 31b formed around the outer periphery of the opening to clamp the core.

In the mold clamping recess 12 of the upper mold 9, there are a plurality of third cavities _C3 communicating with the first cavity _C1 to overflow the molten metal and a fourth cavity _C4 for forming the communication port 7. The upper mold 9 has through holes 32, 3 which are open respectively and communicate with the third cavity _C3 and the fourth cavity _C4 .
3 are formed respectively.

The through holes 32 and 33 have closing pins 34 and 3.
5 are inserted, respectively, and the closing pins 34, 3
The upper end of 5 is a mounting plate 36 disposed above the upper mold 9.
Fixed.

Both cavities C ₃ and C ₄ of each through hole 32 and 34
The small diameter portions 32a, 33a extend upwardly over a predetermined length from the communicating ends of the respective closing pins 34, 3.
5 to close the third cavity C ₃ and the fourth cavity C ₄ , the diameter of the outer portion thereof is larger than the diameter of each closing pin 34 , 35 , so that each closing pin 34 , 35 and each through hole 32,
Air passages 37 and 38 are formed between 33.

A hydraulic cylinder 39 is interposed between the top surface of the upper die 9 and the mounting plate 36, and the operation of the hydraulic cylinder 39 moves the mounting plate 36 up and down to close each closing pin 34, 3.
5 to open and close each small diameter portion 32a, 33a. 40 is a guide rod for the mounting plate 36.

The upper die 9 is provided with a diameter expanding mechanism 41 for holding the cylinder sleeve 3 cast into each of the cylinder barrels 1 ₁ to 1 ₄ , and the mechanism 41 is configured as follows.

A through hole 42 whose center line coincides with the extension axis of the operating pin 30 is formed in the upper mold 9, and a support rod 43 is loosely inserted into the through hole 42. The upper end of the support rod 43 is fixed to a bracket 44 erected on the top surface of the upper mold 9, and a molten metal intrusion prevention plate 45 is fixed to the lower end. A convex portion 45 a that can fit into the concave portion 23 on the top surface of the first molded portion 18 ₁ in the lower mold 11 is formed on the lower surface of the molten metal intrusion prevention plate 45 .

The hollow holding cylinder 46 has a circular outer peripheral surface and a tapered hole 47 with a downward slope from the top to the bottom. The holding cylinder 46 is inserted loosely, and its upper end surface abuts a protrusion 48 protruding from the recess 12 of the upper mold 9, and its lower end surface abuts a molten metal intrusion prevention plate 45. As shown in FIG.
A plurality of slot grooves 49 extending radially from the inner circumferential surface and outer circumferential surface of the circumferential wall are formed alternately and at equal intervals on the circumference.

A hollow actuating rod 50 for expanding the diameter of the holding tube 46 is slid onto the supporting rod 43 over substantially the entire length of the supporting rod 43, and the actuating rod 50 has a tapered shape that fits into the tapered hole 47 of the holding tube 46. Part 50
a, and a perfectly circular portion 50b that is connected to the tapered portion 50a, slides into the through hole 42 of the upper mold 9, and projects from the upper mold 9. A plurality of pins 57 are protruded from the tapered portion 50b, and these pins 57 are inserted into pin holes 58 that are long in the vertical direction of the holding tube 46, thereby allowing the rotation of the holding tube 46 while allowing the vertical movement of the tapered portion 50a. A stop is made.

A hydraulic cylinder 51 is fixed to the top surface of the upper die 9, and hollow piston rods 53 ₁ and 53 ₂ projecting from the upper and lower end surfaces of the hollow piston 52 respectively touch the upper and lower end walls of the cylinder body 54. Penetrating. A true circular portion 50b of the actuating rod 50 is inserted into a through hole 55 passing through the hollow piston 52 and the hollow piston rod 53, and a stopper 56 ₁ to prevent removal is fitted into an annular groove of the circular portion 50b.
56 ₂ on the hollow piston rods 53 ₁ and 53 ₂ ,
The actuating rod 50 is raised and lowered by a hollow piston 52, which is brought into contact with the lower end surface. Four diameter expanding mechanisms 41 are provided corresponding to each of the cylinder barrels ₁₁ to ₁₄ of the cylinder block S.

10 and 11 show a collapsible core 59 for a water jacket, and the core 59 has four cylindrical portions 60 ₁ corresponding to the four cylinder barrels 1 ₁ to 1 ₄ of the cylinder block S. - 60 ₄ , and a core body 61 which lacks the surrounding walls where the adjacent ones overlap with each other, a communication port 7 that communicates the water jacket 6 with the water jacket of the cylinder head, and a reinforcing deck part 8 are formed. In order to achieve this, a plurality of protrusions 62 protrude from the upper end surface of the core body 61, and two cylindrical portions 60 ₂ and 60 ₃ located in the middle on both outer surfaces of the core body 61 in the cylinder barrel arrangement direction. It is comprised of baseboards 63 protruding from both outer surfaces of the baseboard.
Each baseboard 63 has a large diameter portion 63a integrated with the core body 61.
and a small diameter portion 63b protruding from the end surface thereof. In the illustrated example, the core 59 is molded using resin coated sand.

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,
Also, opposing both sides 10 ₁ , 10 ₂ ; 10 ₃ , 1
0 ₄ are moved apart from each other to open the mold. In the diameter expanding mechanism 41, each hydraulic cylinder 51 is operated to lower the actuating rod 50 using the hollow piston 52, and the diameter of the holding cylinder 46 is reduced by moving the tapered portion 50a downward. Also, upper mold 9
The upper hydraulic cylinder 39 is operated to raise the mounting plate 36, thereby opening the small diameter portion 3 that communicates each closing pin 34, 35 with the third and fourth cavities _C3 , _C4 .
2a and 33a. Furthermore, the plunger 16 in the hot water supply cylinder 15 is lowered.

A substantially perfect circular cast iron cylinder sleeve 3 is loosely fitted into each holding cylinder 46, the upper end opening of the cylinder sleeve 3 is fitted into the convex part 48 of the upper mold 9 and closed, and the lower end surface of the cylinder sleeve 3 is closed by fitting into the molten metal. The convex portion 45a of the intrusion prevention plate 45 is aligned with the lower end surface of the convex portion 45a, and the lower end opening of the cylinder sleeve 3 is closed by the molten metal infiltration prevention plate 45. And the hydraulic cylinder 51 of the diameter expansion mechanism 41
is actuated to raise the actuating rod 50 by its hollow piston 52. As a result, the tapered portion 50
Since a moves upward, the diameter of the holding cylinder 46 expands, and the cylinder sleeve 3 is reliably held by the holding cylinder 46 under the force of expanding the diameter.

As shown in FIGS. 5 and 11, the lower edges of the cylindrical portions 60 ₁ , 60 ₄ on both sides of the core 59 are projected onto the top surface of the first molded portions 18 ₁ on both sides of the lower mold 11 by temporary installation pins 25 . The core 5 is engaged with the recess 25a of the core 5.
9. Perform temporary installation.

The two-sided molds 10 ₁ and 10 ₂ are moved a predetermined distance in a direction in which they approach each other, and each core holder 31 and each baseboard 63 are engaged to perform the actual installation of the core 59. That is, the small diameter portion 63b of each baseboard 63 of the core 59 is fitted into the engagement hole 31a of each core receiver 31, and the core 5
9, and the end surfaces of each large diameter portion 63a parallel to the cylinder barrel arrangement direction are abutted against the clamping surfaces 31b of each core receiver 31 to hold the core 59 between the clamping surfaces 3.
1b. Further, the other double-sided molds 10 ₃ and 10 ₄ are also moved in the same manner.

As shown in FIG. 6, the upper mold 9 is lowered and each cylinder sleeve 3 is attached to each cylindrical portion 60 ₁ to 60 of the core 59.
60 ₄ , and insert it into the convex portion 4 of the molten metal intrusion prevention plate 45.
5a is fitted into the recess 23 on the top surface of the first molded part ₁₈₁ . As a result, the convex portion 45a of the molten metal intrusion prevention plate 45
As the operating pin 30 is pushed down, each temporary installation pin 24 is lowered and retracted from the top surface of the first molded part ₁₈₁ . Further, the mold clamping concave portion 12 of the upper mold 9 fits into the mold clamping convex portion 13 of each of the side molds 10 ₁ to 10 ₄ to perform mold clamping.

Molten aluminum alloy is supplied from the melting furnace to the sump 14 of the lower die 11, and the plunger 16 is raised to supply the molten metal from both runners 17 through the weir 19 and from both lower edges of the second cavity C ₂ to the cavities C ₂ and 2. Fill the first cavity _C1 . Both cavities C ₁ ,
Gas such as air in C ₂ is pushed up by the molten metal and escapes above the upper mold 9 through air passages 37 and 38 communicating with the third and fourth cavities C ₃ and C ₄ .

In this case, the bottom surface of the runners is formed in the shape of several steps ascending from the trough portion 14 side so that the cross-sectional area of both runners 17 gradually decreases toward the runner tip 17a as described above. As the plunger 16 rises, the molten metal is smoothly pushed up into the cavity C 2 from both runners 17 and through each weir 19 from the lower ends of both sides of the second cavity C ₂ almost uniformly over _its entire length. Therefore, the molten metal has both cavities C ₁ and C ₂
This prevents turbulence within the molten metal, prevents gases such as air from getting into the molten metal, and prevents the formation of cavities.

When the third and fourth cavities C ₃ and C ₄ are filled with molten metal, the hydraulic cylinder 39 on the upper mold 9 is operated to lower the mounting plate 36 and the closing pins 34 and 3
5 closes the small diameter portions 32a and 33a communicating with both cavities C ₃ and C ₄ .

In the pouring operation, the displacement of the plunger 16 and the pressure of the molten metal for filling the second cavity C ₂ and the first cavity C ₁ with molten metal are controlled as shown in FIG. 12.

That is, the plunger 16 changes its moving speed from the first to
The third speed is controlled in three stages, _V1 to _V3 . In this example, the first speed V ₁ is 0.08 to 0.12 m/sec, and the second speed V ₂ is
0.14 to 0.18 m/sec, and the third speed V ₃ is set to 0.04 to 0.08 m/sec to achieve a significant deceleration state. By controlling the speed in these three stages, the molten metal is prevented from rippling and air etc. Forms a quiet flow of molten metal without involving any gases, and directs the molten metal into both cavities.
C ₂ and C ₁ can be efficiently filled.

In addition, at the first speed V ₁ of the plunger 16, the molten metal only fills both runners 17, etc., so the pressure P ₁ of the molten metal is kept approximately constant, and at the second and third speeds V ₂ and V of the plunger 16. In ₃ , the molten metal is in both cavities C ₁ ,
Since C ₂ is filled with molten metal, the pressure P ₂ of the molten metal rises rapidly. After moving the plunger 16 at the third speed _V3 for a predetermined time, the molten metal filling pressure _P3 is increased to 150°C for about 1.5 seconds.
~400 Kg/cm ² , thereby completely covering the core 59 with the molten metal and forming a molten metal coagulation film on its surface.

After the above-mentioned time has elapsed, the plunger 16 is moved at a reduced speed _V4 , so the pressure _P4 of the molten metal rises, and when the pressure _P5 reaches 200 to 600 kg/ ^cm2 , the plunger 16 stops moving. solidify the molten metal.

If a molten metal coagulation film is formed on the surface of the core 59 by keeping the pressure of the molten metal substantially constant for a predetermined period of time as described above, the core 59 will be protected by the film and will not be damaged during the next pressurization of the molten metal. .

In addition, since the core 59 is held in an accurate position by the molds 10 ₁ and 10 ₂ on both sides via the baseboards 63 of the core 59, when filling the first cavity C ₁ with molten metal and the cavity C ₁ When the molten metal inside is pressurized, the core 59 does not float or sag. Further, the end surface of the large diameter portion 63a of each baseboard 63 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 core 59 tends to swell, the deformation force is supported by each clamping surface 31b, thereby preventing the core 59 from deforming and reducing the thickness around each cylinder sleeve 3. A Siamese cylinder barrel 1 having a uniform thickness is obtained.

By controlling the moving speed of the plunger 16 and the pressure of the molten metal as described above, a closed deck cylinder block material can be cast with substantially the same production efficiency as die casting.

After the molten metal has solidified, the hydraulic cylinder 51 of the diameter expansion mechanism 41 is operated, the operating rod 50 is lowered to remove the diameter expansion force of the holding cylinder 46 against the cylinder sleeve 3, and the mold is opened. After removing the runners, etc., the cylinder block material shown in Figure 4 is created.
Sm is obtained.

The cylinder block material Sm is ground to form each fourth cavity _C4 and each protrusion 6 of the core 59.
When the protrusions 64 formed in cooperation with the protrusions 62 are removed, the protrusions 62 form the communication ports 7, and the reinforcing deck portions 8 are formed between the adjacent communication ports 7.

An opening 66 formed by the communication port 7 of the cylinder block material Sm and each baseboard 63 of the core 59
Using a chisel, punch, drill, etc., insert the core 59.
Roughly disintegrate and then cylinder block material
Vibration is applied to Sm to promote the collapse of the core 59, and sand is removed from the material Sm. In this case, since the core 59 is collapsing due to vibration, approximately 90% of the core 59 is removed from the cylinder block material Sm.

Furthermore, using the communication port 7 and the opening 66, shot blasting or sandblasting is performed on the inside of the cylinder block material Sm, and the core 5 is
9 is completely removed from the material Sm to obtain a water jacket 6.

Cylinder block material with core 59 removed
Sm is annealed, that is, the material Sm is heated to 3.5°C at 220°C.
Heat treatment is performed to remove distortion.

After deburring the cylinder block material Sm and inspecting it, each cylinder sleeve 3 is subjected to machining such as straight circular machining to obtain the cylinder block S shown in FIGS. 1 to 3.

In FIG. 13, a is 1.5 at 200°C, which is the temperature of the entire cylinder block S during engine operation.
The amount of permanent deformation of the inner diameter of the cylinder sleeve 3 at room temperature was measured after heating for a period of time. b shows the case of a comparative example obtained by the conventional method.

In the figure, ~ corresponds to the cylinder sleeves 3 in the cylinder barrels ₁₁ to ₁₄ , respectively.

As is clear from Figures 13a and 13b, in the cylinder block of the comparative example, the amount of permanent deformation of the inner diameter of the cylinder sleeve was at most 55μ at a depth of 30mm from the cylinder head joint surface of the cylinder sleeve.
In addition, there is a large variation in the amount of permanent deformation of each sleeve in the depth range of 10 to 50 mm, which is at high temperature during engine operation, but in the cylinder block S obtained by the present invention, from the cylinder head joint surface The maximum value is 20 μ at a depth of 30 to 50 mm, and the amount of permanent deformation of the inner diameter of the cylinder sleeve 3 is significantly reduced, and the variation in the amount of permanent deformation of each sleeve 3 in the depth range is small. This is because removing the core 59 at room temperature prevents uneven stress from remaining in each sleeve 3.

C. Effects of the Invention According to the present invention, since the core is disintegrated at room temperature and removed from the cylinder block material, the hardness of the material is not reduced. Therefore, there is no need for T6 treatment to restore the hardness of the material, and a highly accurate cylinder block can be obtained simply by annealing the material to remove distortion.

Further, since no heat treatment is required for removing the core, and the annealing treatment is performed at a relatively low temperature and in a short period of time, energy consumption can be significantly reduced and economical efficiency can be improved.

[Brief explanation of drawings]

Figures 1 to 3 show a Siamese type cylinder block, with Figure 1 being a perspective view from above and Figure 2 being a perspective view from above.
The figures are a cross-sectional view taken along the line in Figure 1, Figure 2A is a cross-sectional view taken along the line a-a in Figure 2, Figure 3 is a perspective view taken from below, and Figure 4 is a perspective view taken from above of the Siamese type cylinder block material. Fig. 5 is a vertical sectional front view of the casting device used in the casting process of the present invention when the mold is opened, Fig. 6 is a vertical sectional front view of the casting device when the mold is closed, and Fig. 7 is the line shown in Fig. 6. 8 is a sectional view taken along the line of FIG. 7, FIG. 9 is a sectional view taken along the line of FIG. 5, FIG. 10 is a perspective view of the core seen from above, and FIG. 12 is a graph showing the relationship between the displacement of the plunger and the pressure of the molten metal against time, and FIG. 13 is a graph showing the relationship between the depth of the cylinder sleeve from the cylinder head joint surface and the amount of change in the inner diameter of the cylinder sleeve. 2 is a graph in which a corresponds to the cylinder block obtained by the present invention, and b corresponds to the cylinder block obtained by the conventional method. C ₁ ...first cavity, M...mold as mold,
S...Cylinder block, Sm...Cylinder block material, ₁₁ to ₁₄ ...Cylinder barrel, 3...Cylinder sleeve, 6...Water jacket, 59...Disintegrable core.

Claims (1)

[Claims] 1. When manufacturing an aluminum alloy cylinder block in which a cast iron sleeve is cast into a cylinder barrel and a water jacket is arranged around the outer periphery of the cylinder barrel, the cylinder sleeve and the water jacket surrounding the cylinder sleeve are placed in the cavity of the mold. casting a cylinder block material using molten aluminum alloy with a collapsible core; disintegrating the core at room temperature and removing it from the cylinder block material; a step of applying an annealing treatment;
A method for manufacturing a cylinder block, comprising: performing machining on the cylinder block material.