JPS61144262A - Manufacture of siamese-type cylinder block - Google Patents

Abstract

PURPOSE:To make thermal expansion around the circumference of a sleeve during running approximately uniform and to restrict the gap between a piston and the sleeve in order to prevent the short-circuiting of gas and the waste of oil, by using a preheated cast-iron sleeve with large wall thickness in a specific casting stage, and boring the sleeve thereafter. CONSTITUTION:When a large wall-thickness and high-rigidity cast-iron sleeve 3 having the wall-thickness set to >=10% of its inner diam. is used, the influence of casting strain of the cylinder barrels 11-14 of an aluminum alloy on the sleeve 3 becomes small. Further, by preheating the sleeve 3 up to 150-700 deg.C, the heat of molten metal to be removed by the sleeve 3 is less even if the wall thickness of sleeve 3 is large. Accordingly, the metallurgical structure around the sleeve 3 is made almost uniform because the solidifying speed of molten metal around the sleeve 3 is made uniform. Furthermore, the shrinkage of sleeve 3 follows up the shrinkage of molten metal caused by solidifying. In this way, the residual casting stress of sleeve 3 is made almost uniform around its circumference. When an engine is assembled and driven by subjecting boring work to the inner circumferential surface of each sleeve 3 in this state, the amount of thermal expansion around the circumference of each sleeve 3 is made almost uniform.

Description

[Detailed description of the invention] A6 Object of the invention (1) Industrial application field The present invention relates to a Siamese type cylinder block, in particular, a plurality of cast iron sleeves are cast into a plurality of aluminum alloy cylinder barrels arranged in series. Concerning methods of manufacturing things.

(2) Conventional technology - Conventionally, the Siamese type cylinder block having the above configuration was made by die-casting the cylinder block material by installing a sleeve in each cylinder barrel molding cavity of the mold, and then forming a perfect circle on the inner peripheral surface of each sleeve. Manufactured by processing.

(3) Problems to be solved by the invention Casting distortion occurs in the cylinder barrel of the cylinder block material obtained in the above casting process due to casting pressure and rapid solidification of the aluminum alloy, and the sleeve is thin. In the case of low rigidity, the casting distortion affects the sleeve, causing distortion in the sleeve.

To avoid this, it is possible to increase the thickness of the sleeve, but if the thickness of the sleeve is increased and the sleeve is cast at room temperature, the heat of the molten metal is absorbed by the sleeve, causing the molten metal on the sleeve side to collapse around the water jacket. Since the molten metal solidifies earlier than the molten metal on the core side, the metal structure on the sleeve side and the metal structure on the core side become different. In this case, the thickness of both metal structures around the sleeve in the radial direction of the sleeve is different;
Further, since there is no core between adjacent sleeves, the metal structure between both sleeves is different from the above-mentioned two metal structures. In addition to this metallographic problem, the shrinkage of the sleeve after being heated by the molten metal does not follow the solidification shrinkage of the molten metal, so that the casting stress remaining in the sleeve becomes uneven on its inner peripheral surface.

Further, when the heat of the molten metal is removed by the sleeve, the adhesion between the sleeve and the molten metal deteriorates due to early solidification of the molten metal, and a minute gap is created between the sleeve and the cylinder barrel, resulting in poor heat dissipation of the sleeve.

In this way, the casting stress remaining in the sleeve becomes uneven on its inner circumferential surface, and the heat dissipation of the sleeve deteriorates. Since the amount of thermal expansion on the inner circumferential surface of the piston is uneven, a gap is created between the piston ring and the sleeve, causing problems such as an increase in blow-by gas and wasteful consumption of oil.

In view of the above, the present invention uses a thick-walled and highly rigid sleeve to reduce the influence of casting distortion of the cylinder barrel on the sleeve (and also reduces the influence of casting distortion on the sleeve by heating the sleeve to a predetermined temperature and casting it). A Siamese type cylinder that approximately equalizes casting stress on its inner circumferential surface, improves the heat dissipation of the sleeve, and thereby approximately equalizes the amount of thermal expansion on the inner circumferential surface of each sleeve during engine operation. It is an object of the present invention to provide the above-mentioned manufacturing method capable of obtaining blocks.

B0 Structure of the Invention (Means for Solving Problems 11) The present invention is directed to heating each of the molds by heating the thick-walled and highly rigid sleeve whose wall thickness is set to 10% or more of the inner diameter to 150 to 700°C. The cylinder block material is cast in a cylinder barrel molding cavity, and then the cavity is filled with molten metal under pressure; and the inner peripheral surface of the sleeve is machined into a perfect circle.

(2) Effect If a thick-walled and highly rigid sleeve is used, the influence of casting distortion of the cylinder barrel on it will be reduced.

Furthermore, by heating the sleeve to 150 to 700°C, even if the sleeve is thick, the heat of the molten metal is suppressed from being taken away by the sleeve, and the solidification rate of the molten metal around the sleeve becomes approximately constant, so the metal structure around the sleeve becomes approximately constant. In addition, the shrinkage of the sleeve follows the solidification shrinkage of the molten metal, and as a result, the casting stress remaining in the sleeve becomes approximately equal on its inner peripheral surface. In addition, heating the sleeve slows down the solidification rate of the molten metal around the sleeve, which improves the adhesion between the sleeve and the molten metal, prevents the formation of minute gaps between the sleeve and the cylinder barrel, and improves the heat dissipation of the sleeve.

In this state, when the inner circumferential surface of each sleeve is machined into a perfect circle and an engine is assembled and operated, the amount of thermal expansion on the inner circumferential surface of each sleeve becomes approximately equal.

(3) Example Figures 1 to 3 show a Siamese type cylinder block S obtained according to the present invention, which is made of an aluminum alloy having a plurality of cylinder barrels 11 to 14 arranged in series, and the illustrated example has four cylinder barrels 11 to 14. cylinder block body 2 and cylinder bores 3a that are cast into each cylinder barrel 11 to 14.
It consists of a cast iron sleeve 3 with a thickness of 8 m. The cylinder block main body 2 is composed of a cylinder barrel row 4 that is an assembly of cylinder barrels II to 14, and a crankcase 5 that is integrally provided at the lower edge of the cylinder barrel row 4. A plurality of communicating lowers in the water jacket 6 toward the cylinder head side are opened at the upper end surface of the cylinder barrel row 4 so as to surround each cylinder bore 3a, and a reinforcing deck portion 8 is provided between adjacent communicating lowers. As a result, the cylinder block S is configured as a closed deck type.

Figure 4 shows the cylinder block material Sm obtained by casting.
The inner diameter of the sleeve 3 in this material Sm is 78
The fin has a wall thickness of 10% or more of the inner diameter, for example, 8 fl.

5 to 9 show a casting device for the cylinder block material Sm, which device is equipped with a mold M, and the mold M has an upper mold 9 that can be raised and lowered and is disposed below the upper mold 9. and the fourth
．． In Fig. 5, the first and second side molds 10 are divided into left and right halves.
．． ．． 10□ and both sides type 10,. It is composed of a lower die 11 on which a 10□ is slidably placed.

On the lower surface of the upper mold 9, both side molds 101. A mold clamping recess 1 that defines a cylinder barrel row molding cavity CI in which cylinder barrel molding cavities are assembled in cooperation with lOl.
2 is formed, and the mold clamping convex part 1 fits into the concave part 12.
3 is double-sided type 10. .

10□Protrudes from the top surface.

7th. As shown in FIG. 8, the lower die 11 includes a sump 14 that receives molten aluminum alloy from a melting furnace (not shown), and a hot water cylinder 15 that communicates with the sump 14.
and a plunger 16 that is slid onto the hot water cylinder 15.
A pair of runners 17 are formed which branch into two from the sump portion 14 and extend in the longitudinal direction of the cylinder barrel row molding cavity CI and over approximately the same length. Further, the lower mold 11 has a molding block 18 projecting upward between the two runners 17, and the molding block 18 has a molding block 18 on both sides of the mold i0.
+ and to□ to define a crankcase molding cavity C2. The upper end of the cavity C2 communicates with the cylinder barrel row molding cavity CI, and the lower ends on both sides communicate with both runners 17 via a plurality of weirs 19.

The molding block 18 is located outside of four tall kamaboko coloring brush 1 molding parts 181 formed at predetermined intervals, the adjacent first molding parts 181 and the outermost painting brush 1 molding part 181. Convex-shaped second molded part 18.2, 49.8□1□
Oh, 8. The second molded part 18□ is used to form the rotation space 20 (Figs. 2 and 3) for the crank journal and the crank arm, and the second molded part 18□ is used to form the bearing holder 21 of the crank journal (Figs. 2 and 3). ) is used for molding.

Each layer 19 is provided corresponding to each second molding section 18□, so that the portion of the crankcase molding cavity C□ having a large capacity is quickly filled with molten metal.

Both runners 17 are formed such that the bottom surface of the runners 17 is shaped like several steps ascending from the trough portion 14 side so that the cross-sectional area gradually decreases from the trough portion 14 side toward the runner light 17a. There is. Each rising portion 17c connected to each step portion 17b allows the molten metal to flow into each layer 19.
It is formed diagonally so that it can be guided smoothly.

When the cross-sectional area of the runner 17 is reduced in stages in this way,
In areas with large cross-sectional areas, a large amount of molten metal is pumped through the weir 19 at a slow speed.
In addition, in the small cross-sectional area, a small amount of molten metal can be filled into the crankcase molding cavity C2 through the weir 19 at a high speed. The hot water level rises almost evenly over its entire length,
Therefore, the molten metal does not cause turbulence in the cavity C2 (it is possible to prevent gas such as air from being drawn into the molten metal, thereby avoiding the formation of cavities. Also, the filling operation of the molten metal can be performed efficiently). Therefore, casting efficiency can be improved.

Fifth. As shown in FIG. 6, a positioning protrusion 22 that fits into the inner peripheral surface of the cast iron sleeve 3 is provided on the top surface of each first molded part 18°, and a recess 23 is provided at the center of the positioning protrusion 22. is formed. Also, two first molded parts 18 located on both sides. A through hole 24 passing through the first molded part 181 is formed on both sides of the positioning protrusion 22, and a pair of temporary installation pins 25 are slid into the through hole 24, respectively.
These temporary installation bins 25 are used for temporary installation of water jacket cores. The lower ends of both plate 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 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 tip of each temporary installation pin 25 is attached to the first molded part 1.
8 protrudes from the top surface. 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.

Also, two first molded parts 18 located on both sides. , the first molded portion 18. A through hole 29 is formed through the through hole 29, and an operating bottle 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 actuating pin 29 protrudes into the recess 23, and when the mold is closed, it is pushed down by a collet mechanism described later, thereby moving both plate installation pins 25 into the first molding section 18.
゜It is designed to be pulled in from the top surface.

Positioning means 31 for actually installing sand cores are provided at two locations on the inner surface of the central portion of the first and second side molds tO, 10□. Each positioning means 31 has a small diameter hole 31a.
and a stepped portion 31b formed on the outer periphery of the opening.

In the mold clamping recess 12 of the upper mold 9, a plurality of overflow cavities C2 and a plurality of connecting mouth molding cavities C4 are formed, which communicate with the cylinder barrel row molding cavities C1, and in the upper mold 9, each overflow cavity is formed. Through holes 32 and 33 communicating with C3 and each communication port molding cavity C4 are formed, respectively.

Closing pins 34 and 35 are inserted into the through holes 32 and 33, respectively, and the upper ends of these closing pins 34 and 35 are fixed to a mounting plate 36 disposed above the upper die 9.

A small diameter portion 3 extending upward over a predetermined length from the end of each through hole 32, 34 communicating with both cavities C3, C4.
2a, 33a can be fitted with each of the closing pins 34 and 35 to close the overflow cavity C3 and the connecting mouth molding cavity C4, but the diameter of the outside portion thereof is larger than the diameter of each of the closing pins 34 and 35. , thereby creating an air passage 37.3 between each closing pin 34.35 and each through hole 32.33.
8 is formed.

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 causes the mounting plate 3 to
6 and lower each small diameter part 32 by each closing pin 34,35.
a, 33a are opened and closed. 40 is a guide rod of the mounting plate 36.

The upper die 9 is provided with a collet mechanism 41 for holding the sleeve 3 cast into each of the cylinder barrels II to 14, and the mechanism 41 is configured as follows.

A through hole 42 whose center line coincides with the extension axis of the actuating bottle 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 loft 43 is fixed to a bracket 44 erected on the top surface of the upper die 9, and a molten metal intrusion prevention plate 45 is fixed to the lower end thereof. The lower surface of the molten metal intrusion prevention plate 45 is provided with the first molding portion 1 of the lower mold 11.
A convex portion 45a that can fit into the concave portion 23 on the top surface of 81 is formed.

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. 9, a plurality of slot grooves 49 are formed in the peripheral wall portion of the holding cylinder 46, extending radially from the inner and outer peripheral surfaces thereof, alternately and at equal intervals on the circumference.

A hollow actuating rod 50 for expanding the diameter of the holding cylinder 46 is slidably connected to the supporting rod 43 over substantially the entire length of the supporting rod 43, and the actuating rod 50 is inserted into the tapered hole 4 of the holding cylinder 46.
7, and a true inner 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. Tapered part 50
A plurality of pins 57 are provided protrudingly from b, and these pins 57 are inserted into vertically long pin holes 58 of the holding tube 46, thereby allowing the tapered portion 50a to move up and down while holding the holding tube 46.
rotation will be stopped.

A hydraulic cylinder 51 is fixed to the top surface of the upper mold 9, and a hollow piston rod 53. ．． 53□ passes through the upper end wall and the lower end wall of the cylinder body 54, respectively. The true interior 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,
A retaining stopper 56 fitted into the annular groove inside 50b thereof
1.56□ hollow piston rod 53. ．． Above 53 degrees,
The actuating rod 50 is raised and lowered by a hollow piston 52 while being brought into contact with the lower end surface. The collet mechanism 41 is connected to each cylinder barrel 1 of the cylinder block S.
Four aircraft will be installed corresponding to 1-14.

10th. FIG. 11 shows a sand core 59 as a water jacket orbiting collapsible core, and the sand core 59 includes four cylindrical parts 601 to 604 to surround the four sleeves 3 of the cylinder block S. At the same time, a core body 61 is provided which protrudes from the upper end surface of the core body 61 in order to form a communicating lower which communicates the adjacent core body 61 with a circumferential wall that overlaps with the water jacket of the cylinder head and the water jacket with the water jacket of the cylinder head. and positioning protrusions 63 protruding from both outer surfaces of two cylindrical parts 60z, 60z located in the middle of the core body 61.

Each positioning protrusion 63 is a large diameter portion 63 integrated with the core body 61.
a and a small diameter portion 63b protruding from the end surface thereof.

Next, a description will be given of the casting operation of the cylinder block material Sm using the casting apparatus.

First, as shown in FIG. 5, the upper mold 9 is raised and the molds 10+ and 10z on both sides are moved apart from each other to open the molds. In the collet mechanism 41, each hydraulic cylinder 51 is operated to lower the operating rod 50 using the hollow piston 52, and the diameter of the holding cylinder 46 is reduced by moving the tapered portion 50a downward. In addition, the hydraulic cylinder 39 on the upper mold 9 is operated to raise the mounting plate 36, thereby allowing each of the closing bins 34 and 35 to be connected to the small diameter portions 32a and 33a communicating with the overflow cavity C3 and the communication port molding cavity C4. make them leave. Further, the plunger 16 in the hot water supply cylinder 15 is lowered.

A thick-walled, highly rigid cast iron sleeve 3 having a substantially perfect circle and a wall thickness of 8 fi is heated to 250 to 500°C, loosely fitted into each holding cylinder 46, and the upper end opening of the sleeve 3 is fitted into the convex portion 48 of the upper mold 9. The lower end surface of the sleeve 3 is aligned with the lower end surface of the convex portion 45a of the molten metal intrusion prevention plate 45, and the molten metal intrusion prevention plate 45
The lower end opening of the sleeve 3 is closed. Then, the hydraulic cylinder 51 of the collet mechanism 41 is operated, and the hollow piston 52 raises the operating rod 50. As a result, the tapered portion 50a moves upward, so that the holding tube 46 expands in diameter, and the sleeve 3 is reliably held in the holding tube 46 by receiving the diameter expanding force.

Fifth. As shown in FIG. 11, cylindrical portions 60 on both sides of the sand core 59. ．． 60. The lower edge is attached to the first molding portions 18 on both sides of the lower die 11. The sand core 59 is temporarily installed by engaging with the recess 25a of each temporary installation pin 25 protruding from the top surface of the sand core 59.

The double-sided molds 10+ and 10g are moved a predetermined distance in the direction in which they approach each other, and the small diameter hole 31 of each positioning means 31 is moved.
The small diameter portion 6 of each positioning protrusion 63 in the sand core 59 is shown in a.
3b, and the end faces of each large diameter portion 63a abut against the stepped portions 31b of each positioning means 31, thereby accurately positioning the sand core 59 and holding it on both side walls IL, 10g, and then tightening the sand core 59. 59 books will be installed.

As shown in FIG. 6, the upper mold 9 is lowered and each sleeve 3 is
into each cylindrical part 60+ to 604 of the sand core 59,
The convex portion 45a of the molten metal intrusion prevention plate 45 is fitted into the concave portion 23 on the top surface of the first molded portion 181. As a result, the molten metal intrusion prevention plate 4
Since the operating pin 30 is pushed down by the convex portion 45a of the first molded portion 18. Pull in from the top.

In addition, the mold clamping recess 12 of the upper mold 9 is on both sides of the mold 101°10,
The mold clamping is performed by fitting into the mold clamping convex portion 13 of.

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 flow from both runners 17 through the weir 19 and from the lower edge of the crankcase molding cavity C2 into the cavity. C2 and the cylinder barrel row molding cavity C1 are filled. The gas such as air in both cavities C11ct is pushed up by the molten metal and passes through the air passage 37.3 which communicates with the overflow cavity C3 and the connecting port molding cavity C4.
8 and exits above the upper mold 9.

In this case, both runners 17 are 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 light 17a, as described above. As the plunger 16 rises, the molten metal flows from both runners 17 to each layer 1.
9, the crankcase molding cavity C2 can be smoothly pushed up from both lower ends of the cavity C2 substantially uniformly over its entire length. Therefore, the molten metal does not cause turbulent flow within the cavities C, , C2, and gases such as air are prevented from being drawn into the molten metal, thereby avoiding the formation of cavities.

When each overflow cavity C1 and each continuous molding cavity C6 are filled with molten metal, the hydraulic cylinder 39 on the upper die 9 is operated to lower the mounting plate 36, and the closing pin 34.35 closes both cavities Cs. ,C4
The small diameter portions 32a and 33a that communicate with the are closed.

In the pouring operation, the displacement of the plunger 16 and the pressure of the molten metal for filling the crankcase molding cavity C2 and the cylinder barrel row molding cavity C1 with molten metal are controlled as shown in FIG.

That is, the plunger 16 changes its moving speed to the first to third speeds v.
It is controlled in three stages, 1 to 2. In this embodiment, the first speed V
, is 0.08~Q, 3m/sec, 2nd speed ■2 is 0.1
4 to 0.18 m/sec, 3rd speed ■3 is set to 0.04 to 0.08 m/sec to achieve a significant deceleration state, and this three-stage speed control prevents waving of the molten metal. A quiet molten metal flow is formed without involving gas such as air, and the molten metal is poured into the cavities C, , C.
, can be filled efficiently.

In addition, at the first speed Vl of the plunger 16, the molten metal flows through both runners 1
7 etc., the pressure P of the molten metal is kept approximately constant, and the second and third speeds V, , V, of the plunger 16
Then, the molten metal is both cavities CInc! , the pressure Pg of the molten metal rises rapidly. 3rd plunger 16
After moving the molten metal for a predetermined time at speed V, the filling pressure of the molten metal P
3 is held at 150 to 400 kg/c11 for about 1.5 seconds, thereby completely covering 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 set to speed 4.
As the molten metal is moved at a reduced speed, the pressure P4 of the molten metal increases, and when the pressure Ps reaches 200 to 600 kg/cj, the movement of the plunger 16 is stopped and the molten metal is solidified in this state.

If a molten metal coagulation film is formed on the surface of the sand core 59 by keeping the pressure of the molten metal 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. There is no.

Furthermore, since the sand core 59 is held in an accurate position by the molds 101.10g on both sides through its respective positioning protrusions 63, the sand core 59 is held in an accurate position by the molds 101. The sand core 59 is not lifted up when the molten metal in the mold is pressurized. Further, the end surface of the large diameter portion 63a of each positioning protrusion 63 corresponds to the stepped portion 31 of the positioning means 31 in the double-sided type 103, 10g.
b, the pressure of the molten metal acting on the sand core 59 is supported by the both side molds 101.10□ via the large diameter portion 63a end face of each positioning protrusion 63. Deformation is prevented and cylinder barrel rows 4 with uniform wall thickness around each sleeve 3 can be obtained.

By controlling the moving speed of the plunger 16 and the pressure of the molten metal as described above, a closed deck type 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 collet mechanism 41 is operated, the operating rod 50 is lowered to remove the diameter expansion force of the holding cylinder 46 against the sleeve 3, and the mold is opened, as shown in FIG. A cylinder block material Sm is obtained.

Thereafter, the cylinder block material Sm is subjected to grinding processing to form cavities C4 for molding on each consecutive day and each protrusion 62 of the sand core 59.
By removing the respective protrusions 64 formed in cooperation with the sleeves, each communicating lower is formed, and by removing sand, the water jacket 6 is obtained, and furthermore, the inner circumferential surface of each sleeve 3 is machined into a perfect circle. The cylinder block S shown in FIGS. 1 to 3 is obtained by finishing the wall thickness to 5 fl and performing other predetermined processing.

FIG. 13 shows the metallographic structure of the aluminum alloy in a micrograph (200x magnification) of the cylinder block S obtained according to the present invention. correspond to the sand core 59 side. As is clear from these drawings, in the cylinder block S, the sleeve 3 side, the central part, and the sand core 5
The metal structures on the 9 side are substantially the same, and this is because the solidification rate of the molten metal around the sleeve 3 becomes substantially constant by heating the sleeve 3 to 250 to 500° C. and casting it. Although not shown in the figure, the metal structure between adjacent sleeves 3 is approximately the same as that in FIG. 13(a). Further, the shrinkage of the sleeve 3 may follow the solidification shrinkage of the molten metal, so that the casting stress remaining in the sleeve 3 becomes approximately equal on its inner peripheral surface.

Figure 14 shows the metallographic structure of the aluminum alloy as a micrograph (200x magnification) of a cylinder block in which the sleeve is cast at room temperature, and (a) to (0) are shown in Figures 13 (al to (0)).
C) respectively. As is clear from these drawings, when sleeves at room temperature are used, the metallographic structures on the sleeve side, the center part, and the sand core side are different, and the metallographic structures between adjacent sleeves are as shown in Fig. 14 ( a
) is approximately the same as -. Further, the shrinkage of the sleeve does not follow the solidification shrinkage of the molten metal, and as a result, the casting stress remaining in the sleeve becomes uneven on its inner peripheral surface.

FIG. 15 shows the sleeve 3 and cylinder barrel l in the cylinder block S obtained according to the present invention.

This drawing shows the metallographic structure of cast iron and aluminum alloy under a microscope (400x magnification) of the welded area between the sleeve 3 and the cylinder barrel 1.As is clear from this drawing, there is close contact between the cast iron and the aluminum alloy at the boundary between the sleeve 3 and the cylinder barrel 1, and therefore at the welded area. It has good properties and there are no minute gaps between them. As a result, the heat dissipation of the sleeve 3 is improved.

FIG. 16 shows the metallographic structures of cast iron and aluminum alloy under a microscope (400 times magnification) of the welded part between the sleeve 300 and the cylinder barrel 1001 in a cylinder block in which the sleeve is cast at room temperature. As is clear from this drawing, the boundary between the sleeve 300 and the cylinder barrel IOL,
Therefore, in the welded part, the adhesion between the cast iron and the aluminum alloy is poor, and a small gap G is created between them.

As a result, the heat dissipation of the sleeve 300 deteriorates.

As described above, in the cylinder block S obtained by the present invention, the residual casting stress in the sleeve 3 is approximately uniform on its inner peripheral surface, and the heat dissipation of the sleeve 3 is good. When an engine is assembled and operated using a cylinder block, the amount of thermal expansion on the inner peripheral surface of each sleeve is approximately equal.

Note that if the wall thickness of the sleeve 3 is less than 10% of its inner diameter, the sleeve 3 will have low rigidity and each cylinder barrel 1. ~
14 affects each sleeve 3 and causes distortion in each sleeve 3, which is not preferable.

C6 Effects of the Invention According to the present invention, each thick-walled and highly rigid sleeve whose wall thickness is set to 10% or more of the inner diameter is heated to 150 to 700°C and cast into each cylinder barrel, so that the cylinder relative to the sleeve is The effect of casting strain on the barrel is reduced, the casting stress remaining in the sleeve is approximately evened out on its inner peripheral surface, and the heat dissipation of the sleeve is improved. When an engine is assembled and operated using such a cylinder block, the amount of thermal expansion on the inner circumferential surface of each sleeve is approximately equal, so the generation of gaps between the piston ring and the sleeves should be minimized. Problems such as increased blow-by gas and wasteful oil consumption can be solved.

In addition, the influence of casting strain of each cylinder barrel on each sleeve is small, and the casting stress remaining in the sleeve is approximately equal around its inner circumference, making it possible to make the spacing between adjacent sleeves as close as possible. , which reduces the size of the cylinder block and therefore the entire engine,
Its weight reduction can be achieved.

[Brief explanation of drawings]

1 to 3 show a Siamese type cylinder block manufactured according to the present invention, FIG. 1 is a perspective view seen from above, FIG. 2 is a sectional view taken along line nn in FIG. Figure 4 is a perspective view of the Siamese-type cylinder block material seen from above, Figure 5 is a vertical front view of the casting machine when the mold is opened, and Figure 6 is a vertical front view of the casting machine when the mold is closed. Figure 7 is a sectional view taken along line nn of Figure 1, Figure 8 is a sectional view taken along line nn of Figure 1, Figure 9 is a sectional view taken along line nn of Figure 1,
Figure 0 is a perspective view of the sand core seen from above, Figure 11 is the 10th
Figure 12 is a graph showing the relationship between the displacement of the plunger with respect to time and the pressure of molten metal with respect to time. Figures 13 (a) to (C) are Siamese type cylinder blocks manufactured according to the present invention. Microscopic photograph showing the metal structure of the cylinder barrel in Figure 14(a)
~ (C1 is a microscopic photograph showing the metal structure of the cylinder barrel in a Siamese type cylinder block as a comparative example, and Fig. 15 is a metal structure of the welded part between the cylinder barrel and sleeve in the Siamese type cylinder block manufactured according to the present invention. FIG. 16 is a microphotograph showing the metal structure of the welded part between the cylinder barrel and the sleeve in a Siamese-type cylinder block as a comparative example. CI: A collection of cylinder barrel molding cavities. Cylinder barrel row molding cavity, M...Mold, S
...Cylinder block, Sm...Cylinder block material, 11-14...Cylinder barrel, 3...Sleeve-
Surface σ Figure 4 Figure 3 Illustrated engraving (L with no changes to the content) Figure 1 Figure 2 Procedural manuscript (method) Patent Application No. 59-238098 2, March 19, 1985, Name of the Invention Siamese Manufacturing method for molded cylinder blocks 3, relationship with the case of the person making the amendment Patent applicant name (532) Honda Motor Co., Ltd. 4, agent address 4-5-5 Shinbashi, Minato-ku, Tokyo, date of amendment order February 6, 1985 (Shipping date: February 26, 1985)
6. Written amendment to the procedure to be amended (Self-restraint January 13, 1949 1, Indication of the case 1982 Patent Application No. 238098 2, Name of the invention Relationship with the case Patent applicant name (532) Honda Motor Co., Ltd. Kogyo Co., Ltd. 4th generation
Director 105 Telephone Tokyo 434-4151 5. Contents of amendment subject to amendment 1. The statement in the "Claims" column of the specification is corrected as follows. Manufacture a Siamese type cylinder block with aluminum alloy Siamese cylinder barrel p"E" - 1st grade cast iron sleeve wrapped around the cylinder barrel. Step 14: The thick, highly rigid sleeve whose wall thickness is set to 10% or more of the inner diameter is heated to 150 to 700°C and placed in a mold, and then the liquid volume is measured.
A method for manufacturing a Siamese type cylinder block, which uses the steps of: casting a cylinder block material under pressure and filling it with molten metal; and processing the inner peripheral surface of the sleeve into a perfect circle. 2. Specification, page 2, No. 5. Correct line 6 as follows. "Forging a cast iron sleeve into each cylinder barrel of an aluminum alloy Siamese cylinder barrel formed by joining a plurality of cylinder barrels together" 3, page 2, line 10 of the specification, page 5, lines 1 to 2 , delete the text that says "each service". 4. Page 5, line 2 of the specification: ``cavity''... ``mold''
Corrected to... 5. The following corrections are made to page 6, line 7 to page 10, line 1 of the specification. [This figure shows a Meads-type cylinder block S, which consists of an aluminum alloy cylinder block body 2 and a cast iron sleeve 3. The cylinder block main body 2 has a plurality of cylinder barrels II to 1. It is composed of a Siamese cylinder barrel 1 formed by combining the Siamese cylinder barrel 1, an outer wall part 4 surrounding the Siamese cylinder barrel 1, and a crankcase 5 connected to the lower edge thereof. A water jacket 6 facing the entire circumference of the Siamese cylinder barrel 1 is formed between the Siamese cylinder barrel 1 and the outer wall portion 4, and each cylinder barrel 1. 14 and the outer wall portion 4 are partially connected by a plurality of reinforcing deck portions 8 arranged in the circumferential direction, and the adjacent reinforcing deck portions 8 function as a communicating lower part to the cylinder head side of the water jacket 6. do. As a result, the cylinder block S is configured into a closed deck type. Sleeve 3 is attached to each cylinder barrel 11-1
4, and the sleeve 3 defines a cylinder bore 3a. Figure 4 shows the cylinder block material Sm obtained by casting.
The inner diameter of the sleeve 3 in this material Sm is 78
1 m, and its wall thickness is 10% or more of the inner diameter, for example, 8 mm. 5 to 9 show a casting device for the cylinder block material Sm, which device is equipped with a mold M, and the mold M has an upper mold 9 that can be raised and lowered and is disposed below the upper mold 9. 5th
．． In Fig. 6, the first and second side type IL divided into left and right halves
, 10g, and a lower mold 11 on which the molds 10+ and 10g are slidably placed. A mold clamping recess 12 is formed on the lower surface of the upper mold 9 to define a first cavity C1 in order to mold the Siamese cylinder barrel 1 and the outer wall 4 in cooperation with the side molds 10+ and 10z. Mold clamping convex portions 13 to be fitted are provided protrudingly from the upper surfaces of both side molds 101 and 102. 7th. As shown in FIG. 8, the lower die 11 includes a sump 14 that receives molten metal made of aluminum alloy from a melting furnace (not shown), a hot water supply cylinder 15 communicating with the sump 14, and a hot water supply cylinder 15 that communicates with the sump 14. and a pair of runners 17 which are branched from the tundish portion 14 and extend in the longitudinal direction of the first cavity CI and over approximately the same length as the first cavity CI. Also, the lower mold 11 has both runners 17
A molding block 18 is provided in between and projects upward, and the molding block 18 cooperates with the molds 101 and 102 on both sides to define a second cavity C2 in which the crankcase 5 is molded. The upper end of the cavity C2 is the first cavity CI
There are multiple weirs 19 in both runners 17 at the lower ends of both sides.
communicate via. The molding block 18 includes four tall kamaboko paint brush 1 molding parts 18. which are formed at predetermined intervals. and the adjacent first molded portions 18. Between and outermost brush 1 forming part 18. and a convex-shaped second molded part 18 □ located on the outside of each first molded part 18 . is used to form the crank pin and crank arm rotation space 20 (Figs. 2 and 3),
The second molded part 18□ is the bearing holder 2 of the crank journal.
1 (Figures 2 and 3). Each layer 19 is provided corresponding to each second molding part 18□, so that the large-capacity portion of the second cavity C2 is quickly filled with molten metal. The bottom surface of the runner 17 is formed in several ascending steps from the trough part 14 side so that the cross-sectional area of both runners 17 gradually decreases from the trough part 14 side toward the runner light 17a. . Each rising portion 17c connected to each step portion 17b is formed diagonally so that the molten metal can be smoothly guided to each layer 19. When the cross-sectional area of the runner 17 is reduced in stages in this way,
In areas with large cross-sectional areas, a large amount of molten metal is pumped through the weir 19 at a slow speed.
In addition, in the part with a small cross-sectional area, a small amount of molten metal can be filled into the second cavity C2 through the weir 19 at a high speed. The molten metal level rises almost evenly, and therefore the molten metal flows into the second cavity C.
6. Page 11, line 12 to page 12, line 6 of the specification are corrected as follows. The tip of the recording pin 30 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 the plate installation pins 25 to be retracted from the top surface of the first molding part 181. First and second side molds10. ．． Core holders 31 for actually installing sand cores are provided at two locations in the center of the wall defining the second cavity C2 in 10□. Each core holder 31 has a holding hole 31a for positioning the sand core, and a holding surface 31b formed on the outer periphery of the opening for holding the sand core.
It becomes more. A plurality of third cavities C3 for overflow and a plurality of fourth cavities C4 for forming communication ports are opened in the mold clamping recess 12 of the upper mold 9, and each third cavity C3 is opened in the upper mold 9. and through holes 32 communicating with each fourth cavity C4. ” 7. Page 12 of the specification, lines 15 to 16, ... “Over...T C4” ... is replaced with “Third
．． Corrected to 4th cavity C, C4J... 8. Specification page 13, line 8, page 15, line 12, 16
On page 13, line 17, page 17, line 10, and page 22, line 18, the words "collet" are corrected to "diameter expansion." 9. In the specification, page 14, line 16, ``Tapered portion 50b'' is corrected to ``Tapered portion 50a''. 10. In the specification, page 15, lines 17 to 18, the phrase ``to surround the sleeve 3''... is changed to ``corresponding to the cylinder barrels 1.-14''... Correct. 11. Lines 5 to 8 of page 16 of the specification are corrected as follows. "It is composed of baseboards 63 that are protruded from both outer surfaces. Each baseboard 63 has a large diameter portion 63a that is integral with the core body 61.
and a small diameter portion 63b protruding from the end surface thereof. In this case, the dimensions of the protrusion 62 are set so that it can be loosely inserted into the fourth cavity C4. ” 12. Page 16 of the specification, 19th to last line, ``Overty C4J...''...
・[3rd. Correct to the fourth cavity C3, C, J... 13. Lines 2 to 7 of page 18 of the specification are corrected as follows. the engagement hole 3 of each core receiver 31.
The sand core 59 is positioned by fitting the small diameter portion 63b of each skirting board 63 in the sand core 59 to 1a, and each large diameter portion 63a
The end faces of the sand cores 59 are abutted against the clamping surfaces 31b of each core holder 31, thereby accurately positioning the sand cores 59 and attaching them to both side walls 10. ．． 1
0□ Sand core 59'' 14. The specification page 19, line 2 to page 20, line 8 are corrected as follows. "From the lower edge of the second cavity C2,
and fill the first cavity CI. The gas such as air in both cavities C1 and Cz is pushed up by the molten metal and flows into the third cavity. The air exits above the upper mold 9 through air passages 37 and 38 communicating with the fourth cavities C3 and C4. In this case, the cross-sectional area of the side runner 17 is
Since the bottom surface of the runner is formed in the shape of several steps ascending from the sump 14 side so that the molten metal decreases stepwise toward point a, the rise of the plunger 16 causes the molten metal to rise from both runners 17 to each layer 1.
9, the inside of the cavity C2 can be smoothly pushed up from both lower ends of the second cavity Ct substantially uniformly over its entire length. Therefore, the molten metal flows into both cavities C,,C
No turbulence is caused within the molten metal, and gases such as air are prevented from being drawn into the molten metal, thereby avoiding the formation of cavities. Each third. When the fourth cavities C, , C, 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 35 are used to fill both cavities C, , C, with the molten metal. The communicating small diameter portions 32a and 33a are closed. In the pouring operation, the second. First cavity C2,C
"Plunger for filling molten metal into I" 15, page 20, line 13 of the specification, ...r O, 3J... is corrected to ...ro, 12J... 16. The last line of page 21 to line 13 of page 22 of the specification are corrected as follows. Note: “Also, the sand core 59 expands due to the molten metal,
Since the first protrusion 62 is loosely inserted into the fourth cavity C4, the protrusion 62 follows the expansion of the sand core 59, thereby preventing the protrusion 62 from breaking. Furthermore, the sand core 59 is inserted through each baseboard 63 of the sand core 59 on both sides of the mold 10. ．． Since the sand core 59 is held in an accurate position by the sand core 59, the sand core 59 does not float up when filling the first cavity C1 with molten metal and when pressurizing the molten metal in the cavity C2. Furthermore, the end surfaces of the large diameter portions 63a of each baseboard 63 are both side type 10. ．． 10. Since it abuts against the clamping surface 31b of the core support 31 in
9 tends to swell, the deformation force is applied to each clamping surface 31b.
This prevents deformation of the sand core 59 and provides a Siamese cylinder barrel 1 with uniform wall thickness around each sleeve 3. 17. Lines 4 to 6 of page 23 of the specification are corrected as follows. Sub2 ``Each 4th cavity C4 and each protrusion 6 of the sand core 59
When the protrusions 64 formed in cooperation with the protrusions 62 are removed, a communicating lower is formed by the protrusions 62, and a reinforcing deck portion 8 is formed between adjacent communicating lowers. 18, page 27, line 13 of the specification is corrected as follows. "Figure 2A is a sectional view taken along the line II a - II a in Figure 2, Figure 3 is a perspective view seen from below, and Figure 4 is a side view." 19
, page 28, lines 14-15 of the specification, r C+...
Delete the text "Siri...... Bitay." 20. Drawings 1st to 4th. Fifth. 7th. Figure 8 is corrected as shown in the attached sheet. 21, Figure 2A of the drawings is attached as attached. that's all

Claims (1)

[Claims] In a method for manufacturing a Siamese-type cylinder block in which a plurality of cast iron sleeves are cast into a plurality of aluminum alloy cylinder barrels arranged in series, the thick-walled and highly rigid cylinder block has a wall thickness of 10% or more of the inner diameter. A cylinder block material casting process in which the sleeve is heated to 150 to 700°C and placed in each cylinder barrel molding cavity of the mold, and then the cavity is filled with molten metal under pressure; the inner peripheral surface of the sleeve is machined into a perfect circle. A method for manufacturing a Siamese type cylinder block, comprising: a step of applying;