JPH0141426B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Object of the Invention (1) Field of Industrial Application The present invention relates to a method for manufacturing a Siamese-type cylinder block made of a light alloy.

(2) Prior Art Conventionally, when manufacturing this type of cylinder block, the cylinder block material is cast from a light alloy, and then the material is subjected to predetermined machining.

In the casting process, the upper end surface of the sleeve is brought into contact with the top surface of the Siamese cylinder barrel molding cavity, so that the upper end surface of the Siamese cylinder barrel and the upper end surface of the sleeve are located on the same plane.

(3) Problems to be Solved by the Invention However, according to the above method, dirt such as impurities and oxides contained in the molten metal accumulates at the upper end of the Siamese cylinder barrel, which tends to cause casting defects. There is a problem in that the adhesiveness of the upper end portion to the sleeve deteriorates due to the generated solidification and contraction force in the axial direction of the sleeve.

An object of the present invention is to provide the aforementioned manufacturing method that can solve the aforementioned problems.

B. Structure of the Invention (1) Means for Solving Problems The present invention connects adjacent cylinder barrels of a plurality of cylinder barrels arranged in series together by encasing a cast iron sleeve with its axis directed in the vertical direction. A cylinder block material comprising a Siamese cylinder barrel, and a Siamese annular body that connects adjacent annular bodies of a plurality of annular bodies protruding from the upper end of the Siamese cylinder barrel so as to cover the upper end surface of each sleeve. It is characterized by using the steps of: casting the Siamese annular body from a light alloy; and cutting the Siamese annular body from the Siamese cylinder barrel.

(2) Effect When the cylinder block material is provided with a Siamese annular body as described above, dirt such as impurities and oxides contained in the molten metal during casting accumulates in the Siamese annular body located above the Siamese cylinder barrel. This makes it possible to prevent casting defects in the Siamese cylinder barrel.

In addition, since each annular body covers the upper end surface of each sleeve, the solidification contraction force generated in the Siamese cylinder barrel in the axial direction of the sleeve is absorbed by each annular body being locked onto the upper end surface of each sleeve. At the same time, a solidification contraction force is generated in each annular body in the radial direction of the sleeve, thereby improving the adhesion of the upper end of the Siamese cylinder barrel to the sleeve.

By cutting out the Siamese annular body from the Siamese cylinder barrel, the casting defect part is removed, and after this removal, the Siamese cylinder barrel will no longer undergo solidification shrinkage in the sleeve axis direction. Good adhesion between the upper end and the sleeve is maintained.

(3) Example Figures 1 to 3 show a Siamese-type cylinder block S made of aluminum alloy as a light alloy obtained by the present invention.
is a Siamese cylinder barrel 1 formed by connecting adjacent cylinder barrels 1 ₁ to 1 4 of a plurality of cylinder barrels 1 1 to _{1 4} arranged in series, and an outer wall portion 2 surrounding the Siamese cylinder barrel 1; It is equipped with a crankcase 3 connected to the lower edge of the outer wall 2, and a cast iron sleeve 4 whose axis is directed in the vertical direction is cast around each cylinder barrel ₁₁ to ₁₄ .
Each sleeve 4 defines a cylinder bore 5 .

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. It functions as a mouth 7. As a result, the cylinder block S is constructed into a closed deck type.

4 and 4A show a cylinder block material Sm for obtaining the cylinder block S, and the material Sm is made of a Siamese annular shape protruding from the upper end of the Siamese cylinder barrel 1 in addition to the constituent elements of the cylinder block S. It has a body R.
A plurality of Siamese annular bodies R cover the outer periphery of the upper end surface 4a of each sleeve 4 and a part of the upper surface of the outer wall 2, and the illustrated example includes four annular bodies r1 _to
It is a combination of the neighboring parts of r ₄ . This Siamese annular body R is cut out from the Siamese cylinder barrel 1 after casting. Also each sleeve 4
The lower end surface 4b is also covered by a pair of opposing arcuate bodies A and adjacent bearing holders 21 of the crank journal.

Figures 5 to 9 show the cylinder block material Sm.
The device is equipped with a mold M, and the mold M is provided with an upper mold 9 that can be raised and lowered and below the upper mold 9. The first and second side molds 10 ₁ , 10 ₂ of the two-split type, and the third and fourth side molds of the left and right halves in FIG.
It is composed of side molds 10 ₃ and 10 ₄ and a lower mold 11 on which the side molds 10 ₁ to 10 ₄ are slidably placed.

A mold clamping recess 12 is formed on the lower surface of the upper mold 9 to define a first cavity C ₁ for molding the Siamese cylinder barrel 1 and the outer wall 2 in cooperation with the upper half of each side mold 10 ₁ to 10 ₄ . is formed, and a mold clamping convex portion 13 that fits into the concave portion 12 is formed on each side mold 10 ₁
~10 ₄ Protrudes from the top 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), a hot water cylinder 15 communicating with the sump 14, and a hot water supply cylinder 15 that communicates with the sump 14. A plunger 16 that slides onto the hot water supply cylinder 15 and a
branching into the book 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 projecting upwardly in between, 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 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 each second forming part 18 ₂ so that the molten metal can be quickly injected into the larger capacity part of the second cavity C ₂ .

Both runners 17 are located at the runner tip 17a from the water reservoir 14 side.
The bottom surface of the runner 17 is formed in the shape of several steps ascending from the trough portion 14 side so that the cross-sectional area gradually decreases toward the bottom. 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 in stages in this way, a large amount of molten metal is injected into the second cavity _C2 through the weir 19 at a slow speed in the large cross-sectional area, and a small amount is injected in the small cross-sectional area. can be injected into the second cavity C ₂ through the weir 19 at a high speed, so that the molten metal in 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 injection work 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 peripheral surface of the cast iron sleeve 3 is protruded from the top surface of the cast iron sleeve 3, and a recess 23 is formed in the center of the positioning protrusion 22. Further, in the two first molded parts 18 ₁ located on both sides, through holes 24 passing through the first molded parts 18 ₁ are formed on both sides of the positioning protrusion 22, and a pair of temporary installation pins 25 are respectively inserted into the through holes 24. These temporary installation pins 25 are used for temporary installation of a sand core for a water jacket, which will be described later. Both temporary installation pins 2
The lower end of 5 is fixed to a mounting plate 26 disposed below the forming block 18. 2 on the mounting plate 26
The book support rods 27 are inserted, and each support rod 2
A coil spring 28 is compressed between the lower part of the mounting plate 7 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 tip of each temporary installation pin 25 is attached to the first molded part 18 ₁ It protrudes from the top. A recess 25 that engages with the lower edge of the sand core on the tip surface of each temporary installation pin 25
a is formed.

In addition, in the two first molded parts 18 ₁ located on both sides,
A through hole 29 passing through the first molded portion 18 ₁ is formed at a bisecting position between both 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 opening the mold, actuating pin 3
The tip of the pin 0 protrudes into the recess 23, and is pushed down by a diameter expanding mechanism to be described later when the mold is closed, thereby causing both temporary installation pins 25 to be retracted from the top surface of the first molded part ₁₈₁ .

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 clamping surface 31b formed on the outer periphery of the opening to clamp the sand core.

A third cavity C3 communicating with the first cavity C1 is formed in the mold clamping recess 12 of the upper mold 9 in order to mold the Siamese annular body _R , and a third cavity _C3 communicating with the third cavity _C3 is formed in the upper mold 9. A plurality of gas vent holes 32 are 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 mold 9.

A small diameter portion 32a of each gas vent hole 32 that extends upward over a predetermined length from the end communicating with the third cavity _C3 is fitted with the lower end of each closing pin 34 to close the third cavity _C3 . I'm starting to get it.

A hydraulic cylinder 39 is interposed between the upper surface of the upper die 9 and the mounting plate 36, and the operation of the hydraulic cylinder 39 raises and lowers the mounting plate 36, and each closing pin 34 opens and closes each small diameter portion 32a. There is. 4
0 is a guide rod of the mounting plate 36.

The upper mold 9 is provided with a diameter expanding mechanism 41 for holding the sleeve 4 cast into each cylinder barrel 1 ₁ to 1 ₄ while applying a diameter expanding force to the sleeve 4, and the mechanism 41 is as follows. It is configured as follows.

A through hole 42 whose center line coincides with the extension axis of the actuating pin 30 is formed in the upper mold 9;
A support rod 43 is loosely inserted into 2. The upper end of the support rod 43 is fixed to a bracket 44 erected on the upper surface of the upper die 9, and a molten metal intrusion prevention plate 45 is fixed to the lower end. Molten metal intrusion prevention plate 45
A convex portion 45a that can fit into the concave portion 23 on the first side of the first molded portion ₁₈ in the lower die 11 is formed on the lower surface of the mold.

Hollow holding cylinder 46 that applies diameter expansion force to the sleeve 4
has a circular outer peripheral surface and a tapered hole 47 with a downward slope from the top to the bottom, and the lower part of the support rod 43 protruding downward from the upper die 9 is loosely inserted into the tapered hole 47 of the holding cylinder 46. The upper end surface of the holding tube 46 contacts the lower end surface of a stepped convex portion 48 that defines the annular portion of the third cavity C ₃ in the upper mold 9, and the lower end surface of the holding tube 46 contacts the molten metal intrusion prevention plate 45. come into contact with As shown in FIG. 9, a plurality of slot grooves 49 are formed in the peripheral wall of the holding cylinder 46, extending in the radial direction from the inner and outer peripheral surfaces thereof, alternately and at equal intervals on the circumference.

A hollow actuation rod 50 for expanding the diameter of the holding cylinder 46 is slid onto the support rod 43 over substantially the entire length of the support rod 43, and the actuation rod 50 has a tapered portion that fits into the tapered hole 47 of the holding cylinder 46. 50a
, 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 50a, and these pins 57 are inserted into vertically long pin holes 58 of the holding tube 46, thereby preventing the holding tube 46 from rotating while allowing the tapered portion 50a to move up and down. will be done.

A hydraulic cylinder 51 is fixed to the upper surface of the upper mold 9, and hollow piston rods 53 ₁ and 53 ₂ projecting from the upper and lower end surfaces of the hollow piston 52 penetrate through the upper and lower end walls of the cylinder body 54, respectively. ing. The circular portion 50b of the actuating rod 50 is inserted into the through hole 55 passing through the hollow piston 52 and the hollow piston rod 53, and the stopper 56 ₁ is fitted into the 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.

Figures 10 and 11 are sand cores 59 for water jackets.
The sand core 59 is the cylinder block S.
The core body 61 is provided with four cylindrical portions 60 ₁ to 60 ₄ corresponding to the four cylinder barrels 1 ₁ to 1 ₄ , and has a core body 61 lacking a circumferential wall that overlaps the adjacent ones, and A plurality of protrusions 62 protruding from the upper end surface of the core body 61 and a plurality of protrusions 62 in the cylinder barrel arrangement direction of the core body 61 are provided to form a communication port 7 and a reinforcing deck portion 8 that communicate the jacket with the water jacket of the cylinder head. Both outer surfaces, in the illustrated example, are comprised of baseboards 63 protruding from both outer surfaces of two cylindrical portions 60 ₂ and 60 ₃ located in the middle. Each baseboard 63 is formed of a large diameter portion 61a that is integral with the core body 61, and a small diameter portion 63b 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. In the diameter expansion mechanism 41, each hydraulic cylinder 5
1, the hollow piston 52 lowers the actuating rod 50, and the diameter of the holding cylinder 46 is reduced by moving the tapered portion 50a downward. Further, the hydraulic cylinder 39 on the upper surface of the upper mold 9 is operated to raise each closing pin 34 via the mounting plate 36, thereby opening each gas vent hole 32. Furthermore, the plunger 16 in the hot water supply cylinder 15 is lowered.

A substantially perfect circular cast iron sleeve 4 is loosely fitted into each holding cylinder 46, and the upper end opening of the sleeve 4 is connected to the convex portion 48 of the upper mold 9.
The lower end surface of the sleeve 4 is fitted into the molten metal infiltration prevention plate 45, and the molten metal intrusion prevention plate 45 closes the lower end opening of the sleeve 4. 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 holding cylinder 46 expands in diameter, and the sleeve 4 is reliably held in 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 and 60 ₄ on both sides of the sand core 59 are connected to temporary installation pins that protrude from the top surface of the first molding portions 18 ₁ on both sides of the lower mold 11. The sand core 59 is temporarily installed by engaging the recess 25a of the sand core 59.

The sand cores 59 are permanently installed by moving the double-sided molds 10 ₁ and 10 ₂ a predetermined distance in the direction in which they approach each other, and engaging each core receiver 31 with each baseboard 63. That is, the sand core 59 is positioned by fitting the small diameter portion 63b of each baseboard 63 in the sand core 59 into the engagement hole 31a of each core receiver 31, and also aligning the cylinder barrel arrangement direction of each large diameter portion 63a. The end surface parallel to each core receiver 31
The sand core 59 is held between the holding surfaces 31b by the sand cores 31b. 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 sleeve 4 is inserted into each cylindrical portion 60 ₁ to 60 ₄ of the sand core 59, and the convex portion 45a of the molten metal infiltration prevention plate 45 is first formed. Part 18 ₁ fits into the recess 23 on the top surface. The actuating pin 30 is secured by the convex portion 45a of the molten metal intrusion prevention plate 45.
is pushed down, so each temporary installation pin 24 descends and is retracted from the top surface of the first molded part ₁₈₁ . Further, each protrusion 62 of the sand core 59 is loosely inserted into the third cavity _C3 . 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. In this case, a space s in which the arcuate body A is formed is formed between the lower end surface of the sleeve 4 and the top surface of the first molded portion 18 ₁ .

A molten metal made of aluminum alloy is supplied from the melting furnace to the sump 14 of the lower mold 11, and the plunger 16 is raised to allow the molten metal to pass through the weir 19 from both runners 17 and into the cavity from both lower edges of the second cavity _C2 .
C ₂ , first cavity C ₁ and third cavity C ₃
inject sequentially. Gas such as air in each cavity C ₁ to _{C 3} is pushed up by the molten metal and escapes above the upper mold 9 through the gas vent hole 32 .

In this case, both runners 17 are the runners 17 as described above.
Since the bottom of the runner is formed in the shape of several steps ascending from the sump portion 4 side so that the cross-sectional area gradually decreases toward point a, the molten metal flows from both runners 17 as the plunger 16 rises. Through each weir 19, the inside of the second cavity C ₂ can be smoothly pushed up from the lower ends of both sides of the second cavity C ₂ almost evenly over its entire length. Therefore, the molten metal does not cause turbulent flow within both cavities C ₁ and C ₂ , and it is possible to prevent gases such as air from being drawn into the molten metal, thereby avoiding the formation of cavities. Further, dirt such as impurities and oxides contained in the molten metal rises within the first and second cavities C ₁ and C ₂ and accumulates in the third cavity C ₃ .

After the third cavity C ₃ is filled with molten metal, the hydraulic cylinder 39 on the upper mold 9 is operated to
6 is lowered, and the third
The small diameter portion 32a communicating with the cavity _C3 is closed and the molten metal is solidified under pressure.

The displacement of the plunger 16 and the pressure of the molten metal during the pouring operation 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.
It can be efficiently injected into C ₂ and C ₁ and pressurized.

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 increases.
After moving the plunger 16 at the third speed _V3 for a predetermined time, the pressure of the molten metal _P3 is increased to 150 to 400 for about 1.5 seconds.
Kg/cm ² , thereby completely surrounding the sand 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 decelerated and moved again at the speed V ₄ , so that the pressure of the molten metal P ₄
further increases, and the pressure P ₅ becomes 200 to 600 Kg/cm ²
When this occurs, the movement of the plunger 16 is stopped and the molten metal is solidified in this state.

In this case, since a diameter expanding force is applied to the sleeve 4, deformation of the sleeve 4 due to the pressure of the molten metal is prevented.

Furthermore, if a molten metal coagulation film is formed on the surface of the sand core 59 by keeping the pressure of the molten metal substantially constant for a predetermined period of time as described above, the sand core 59 will be protected by the film and damaged during the next pressurization of the molten metal. Never.

Furthermore, since the sand core 59 is held in an accurate position by the molds 10 ₁ and 10 ₂ on both sides through its baseboards 63, the sand core 59 is held in an accurate position by the molds 10 1 and _{10 2} on both sides. When the molten metal in ₁ is pressurized, the sand core 59 does not float or sag. In addition, since the end surfaces of the large diameter portions 63a of each baseboard 63 abut against the clamping surfaces 31b of the core receivers 31 in the double-sided molds 10 ₁ and 10 ₂ , when the sand cores 59 tend to swell, The deformation force is supported by each clamping surface 31b, thereby preventing deformation of the sand core 59, and providing a Siamese cylinder barrel 1 with uniform wall thickness around each sleeve 4.

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 completely solidified, the hydraulic cylinder 51 of the diameter expanding mechanism 41 is operated to lower the operating rod 50 to remove the diameter expanding force of the holding cylinder 46 against the sleeve 4.

In the cylinder block material Sm, the upper end surface 4a of each sleeve 4 is covered by each of the annular bodies _r1 to _r4 , and the lower end surface 4b of each sleeve 4 is covered by the pair of arcuate bodies A and the bearing holder 21. , the solidification contraction force generated in the Siamese cylinder barrel 1 in the sleeve axial direction is applied to each annular body r ₁
~r ₄ is attached to each sleeve upper end surface 4a, and each arcuate body A
and the bearing holder 21 is connected to the lower end surface 4 of each sleeve 4.
b, respectively.
At the same time, a solidification contraction force is generated in each of the annular bodies r ₁ to r ₄ , each arcuate body A, and each bearing holder 21 in the radial direction of the sleeve.

This makes it possible to improve the adhesion of the upper and lower ends of the Siamese cylinder barrel 1 to the sleeve 4.

After demolding, the Siamese annular body R is removed from the Siamese cylinder barrel 1 and the outer wall 2 to remove casting defects, and each communication port 7 and reinforcing deck part 8 are formed by each protrusion 62 of the core 59. The water jacket 6 is obtained by removing sand, and the cylinder block S shown in Figs. can get.

Note that a magnesium alloy or the like can be used as the light alloy.

C Effects of the Invention According to the present invention, when casting the cylinder block material, it is possible to collect dirt such as impurities and oxides contained in the molten metal in the Siamese annular body, thereby preventing the occurrence of casting defects in the Siamese cylinder barrel. .

In addition, each annular body constituting the Siamese annular body suppresses the solidification contraction force generated in the Siamese cylinder barrel in the axial direction of the sleeve, and at the same time utilizes the solidification contraction force generated in each annular body in the sleeve radial direction. This improves the adhesion of the upper end of the Siamese cylinder barrel to the sleeve.

After casting, the Siamese annular body is removed from the Siamese cylinder barrel, which removes casting defects and maintains the adhesion of the upper end of the Siamese cylinder barrel to the sleeve, resulting in a high quality light alloy Siamese cylinder block. can be provided.

[Brief explanation of drawings]

1 to 3 show a Siamese type cylinder block 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 of FIG. 1, and FIG. -a line sectional view, 3rd
The figure is a perspective view seen from below, and Figure 4 is a perspective view of the Siamese type cylinder block material seen from above.
Figure 4A is a sectional view taken along the line a-a in Figure 4, Figure 5 is a vertical sectional front view of the casting machine when the mold is opened, Figure 6 is a vertical sectional front view of the casting machine when the mold is closed, and Figure 7 is a vertical sectional view of the casting machine when the mold is closed. Figure 6 is a cross-sectional view along the line, Figure 8 is a cross-sectional view along the line in Figure 7,
Figure 9 is a sectional view taken along the line shown in Figure 5, Figure 10 is a perspective view of the sand core seen from above, and Figure 11 is Figure 10 XI.
-XI line sectional view, FIG. 12 is a graph showing the relationship between the pressure of the molten metal and time. R...Siamese annular body, r ₁ ~ r ₄ ... Annular body, Sm... Siamese type cylinder block material, 1... Siamese cylinder barrel, 1 ₁ ~
1 ₄ ...Cylinder barrel, 4...Sleeve, 4a
...Top surface.

Claims (1)

[Claims] 1. A Siamese cylinder barrel in which adjacent cylinder barrels of a plurality of cylinder barrels arranged in series are connected to each other by surrounding a cast iron sleeve whose axis is directed in the vertical direction, and the Siamese cylinder barrel is formed so as to cover the upper end surface of each sleeve. casting a cylinder block material from a light alloy, including a plurality of Siamese annular bodies protruding from the upper end of the barrel and connecting adjacent ones of the annular bodies; casting the Siamese annular body into the Siamese cylinder barrel; A method for manufacturing a Siamese type cylinder block made of a light alloy, comprising: a step of cutting the cylinder block;