KR100537083B1 - Cylinder block of multi-cylinder engine and the method of producing same - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder block of a multi-cylinder engine and a method for manufacturing the same, wherein a jacket core (30) for forming a cylinder jacket (8) of a multi-cylinder engine (E) is molded and a mold for forming a cylinder block (28) The core 30 for the jacket is mounted, and the molten metal is poured into the cylinder block forming mold 28 to cast the cylinder block of the multi-cylinder engine, and the bore wall of the multi-cylinder engine E In the head adjacent part of (4), the channel forming core 31 for forming the cooling water path 10 connecting the cylinder jacket 8 and the head jacket 22 is formed by spherical particles having a lower expansion rate than that of ordinary silica sand. It is another feature that the water channel forming core 31 is attached to the bore wall corresponding position of the jacket core 30 before molding and pouring molten metal.

Description

Cylindrical block of multi-cylinder engine and its manufacturing method {Cylinder block of multi-cylinder engine and the method of producing same}

The present invention relates to a cylinder block of a multi-cylinder engine and a method of manufacturing the same, and more particularly, to a technique of forming a cooling water passage in a bore wall of an adjacent cylinder bore.

In order to reduce the size of the multi-cylinder engine and to reduce the space between the cylinder bores, or to increase the engine capacity by increasing the displacement, the cylinder bore has been largely formed by conventionally making the bore wall as thin as possible. A technique for forming a cooling water channel has been proposed. For example, FIGS. 7-9 all show prior art related to the proposal of the assignee of the present invention. 7 is a longitudinal sectional view of a coolant path formed in a bore wall, FIG. 8 is a perspective view of a core for a cylinder jacket, and FIG. 9A is a perspective view of a channel forming member made of sheet metal. 9B is a plan view showing a state in which a molding sand is filled in the channel forming member, and FIG. 9C is a front view illustrating a state in which a molding sand is filled in the channel forming member.

The prior art is disclosed in, for example, Japanese Patent Laid-Open No. 9-32629, and as shown in FIG. 7, a channel forming member made of sheet metal in a head adjacent portion of a bore wall 4 of a multi-cylinder cylinder block 1 is shown. Casting 110 to form a cooling water passage (10). The channel forming member 110 made of sheet metal is formed by joining two molded sheet metal members to each other by welding or caulking, as shown in Fig. 9A.

As shown in FIG. 7, the cooling water passages 10 have cooling water introduction portions at lower portions thereof.

It consists of a pair of left and right ascending channels 12 having 13 and a plurality of cross-passages 15 provided in multiple stages up and down so as to connect the rising channels 12 to each other. Cooling water in the ()) is introduced from the cooling water introduction portion 13, the cross-passage channel 15 and the rising channel

It is comprised so that the head adjoining part of the bore wall 4 may be cooled by making it pass through the head jacket 22 past 12. As shown in FIG. Moreover, the part 11 in which the cooling water path 10 is not formed among the channel forming members 110 is welded, and it is set as a non-cavity part. The sheet metal channel forming member

110 is cast into the bore wall 4 as follows.

As shown in Figs. 9B and C, the water channel forming member 110 is pre-filled with molding sand, and it is mounted on the bore wall corresponding position of the jacket forming mold (not shown). Then, the jacket forming mold is press-filled with the core forming machine to form the jacket core 30 shown in FIG. 8. In this way, the channel forming member made of sheet metal

110 is integrated into the jacket core 30. Further, the channel forming member 110 made of sheet metal is used because the casting sand lacks fluidity, fillability, and transverse rupture strength, and thus is not suitable for forming the cooling water passage 10.

Subsequently, the jacket core 30, the crank bore core, the cam balancer core, and the like are attached to the cylinder block forming mold (not shown), and molten metal is poured into the cylinder block forming mold. . After cooling, sand is removed to complete casting of the multi-cylinder cylinder block. In this way, the channel forming member made of sheet metal

110 is cast into the bore wall 4 and a cooling water passage 10 is formed in the bore wall 4 to connect the cylinder jacket 8 and the head jacket 22.

According to the prior art, since the channel forming member 110 made of sheet metal is cast into the bore wall 4, the following problem occurs.

Since the jacket core 30 and the channel-forming member 110 made of sheet metal have different expansion rates, the jacket core 30 may be cracked or deformed after molten metal is poured.

In addition, the joining of the channel forming member 110 made of sheet metal with the molten metal is likely to be incomplete, the bore wall 4 is skewed during the machining of the cylinder bore, and the channel forming member and the bore are formed by peeling of the channel forming member. The cooling effect falls by the fall of the heat conduction between walls.

In order to ensure the processing strength of the bore wall 4 sufficiently to prevent the cylinder bore from being skewed during processing, the minimum thickness of the bore wall 4 must be increased, and the cross-sectional area of the cooling water passage 10 is reduced by that much. You can't help it.

Therefore, prior to the present invention, attempts have been made to form a core for forming a channel using a casting sand that has been conventionally used. However, since the casting sand is not spherical, the filling ability is poor because of the large spacing between the molding sand particles, and the shape holding force between the casting sands is weak. Therefore, in order to secure the shape holding force between molding sands, and the required lateral breaking force, it is necessary to enlarge the adhesive content of molding sand.

However, it is possible to increase the content of the adhesive of the molding sand for molding the core for forming the channel.

In the step of pouring cotton and molten metal, the amount of gas generated by evaporation and scattering of the adhesive increases, and voids easily occur. In addition, since the core for forming a channel has a smaller mass and a smaller heat capacity than other parts, when the adhesive is evaporated and scattered, the shape retaining force is extremely lost, and the channel is broken due to pressure and overheating of the molten metal. When not formed, so-called "molding sand residue" occurs. For this reason, undesired irregularities may be generated on the inner surface of the channel due to the casting sand included in the casting, or the casting sand is burned and attached to the casting surface, and the channel is narrowed. It leads to degradation.

The present invention provides a technique for forming a cooling water channel using a channel forming core formed of a core casting sand, which will be described later, in place of a conventional sheet metal channel forming member.

(1) Eliminate cracking of the jacket forming core due to the difference in expansion rate,

② To solve the problem of the bore wall crooked when machining the cylinder bore,

③ To solve the problem of peeling according to the prior art to increase the cooling effect of the bore wall,

④ Ensure sufficient machining strength of cylinder bore and cross section of cooling water passage,

⑤ Solving the above problems in the case of forming a core for forming a channel with a casting sand used in the related art, forming a channel for forming a channel having a large lateral breaking force by adding a small amount of adhesive to form a high precision cooling water channel. It is technical problem to do.

In order to solve the above problems, the cylinder block of the multi-cylinder engine according to claim 1 has the following basic configuration. That is, the cooling water path 10 in which the casting surface is exposed is provided in the head adjoining part of the bore wall 4 of the multi-cylinder engine E. The cooling water channel 10 includes a plurality of left and right pairs of rising channels 12 each having a cooling water introduction unit 13 at a lower portion thereof, and a plurality of crossing channels formed up and down in multiple stages so as to connect these climbing channels 12 to each other ( 15), the cooling water in the left and right cylinder jacket (8) from the cooling water introduction portion (13) to the cooling water

It is configured to introduce into (10) and distribute it to the head jacket 22.

Invention of Claim 1 has the following characteristic structures in order to solve the said subject. That is, in the cylinder block of the multi-cylinder engine having the above-mentioned basic structure, the connecting portion 4b connecting the first wall portion 4c and the second wall portion 4d of the bore wall 4 between the upper and lower traverse channels 15 is provided. By installing, it is an up-and-down crossing path in the said connection part 4b

(15) is separated, and the height H of each cross channel 15 is set higher than the height h of the connection part 4b.

In the invention described in claim 2, in the cylinder block of the multi-cylinder engine according to claim 1, the front and rear widths (W) of the respective traverse channels (15) are 1 of the minimum thickness (T) of the bore wall (4). It is set to 2/3 or less from / 3 or more, and the height (H) of each cross channel 15 is the connecting portion

It is characterized by setting to 2 times or more and 3 times or less of the height h of (4b).

In the invention described in claim 3, in the cylinder block of the multicylinder engine according to claim 1 or 2, a pair of left and right cylinder heads are continuously connected to both left and right portions of the head adjoining portion 4a of the bore wall 4. The fastening boss portion 5 is formed, and the coolant introduction portion

(13) is arranged close to the lower surface of the above-mentioned cylinder head fastening boss portion 5 to extend the opening up and down, and to spread back and forth along the cylinder outer peripheral surface 3b.

The invention according to claim 11 has the following basic configuration.

That is, the jacket core 30 for forming the cylinder jacket 8 of the multi-cylinder engine E is molded, and the said jacket core 30 is mounted in the cylinder block formation mold 28, and the said cylinder A molten metal is poured into the block forming mold 28 to cast a cylinder block of a multi-cylinder engine.

Moreover, the invention of Claims 11-14 has the following characteristic structures. The water-refining core 31 for forming the cooling water passage 10 connecting the cylinder jacket 8 and the head jacket 22 to the head adjacent portion of the bore wall 4 of the multi-cylinder engine E is obtained by general silica sand. It is formed by spherical spherical sand of lower expansion rate, and the channel forming core 31 is attached to the bore wall corresponding position of the jacket core 30 before pouring molten metal. It is a manufacturing method of a cylinder block of a multi-cylinder engine.

(Example)

Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1A is a partial plan view of a cylinder block of a multi-cylinder engine according to an embodiment of the present invention, FIG. 1B is a longitudinal sectional view of a cooling water passage formed in a bore wall as a main portion of the cylinder block, and FIG. 2 is a cooling water according to the present invention. A longitudinal cross-sectional view of the main portion of a vertical multicylinder engine having a furnace.

As shown in FIG. 2, the vertical multi-cylinder engine E fixes the cylinder head 20 with the head bolt 6 on the cylinder block 1 in which the crankcase is integrally formed, and the cylinder block 1. Cylinder jacket (8) formed on the cylinder head (20) and the head jacket (22) formed on the cylinder head (20) are connected to the cooling water passage (10) formed in the head adjacent portion of the bore wall (4). The head adjoining portion of the bore wall 4 is strongly cooled by the cooling water introduced from the cooling water passage 10 to the cooling water passage 10.

In the cylinder block 1 of the multi-cylinder engine according to the present invention, as shown in Figs. 1A and 2, the plurality of cylinders 3 are installed side by side in front of and behind, and the cylinders 3 adjacent to the front and rear are seen by the wall 4. And the cylinder jacket 8 is formed so as to surround the continuous cylinder 3 at the same time. The cooling water path 10 shown in FIG. 1A, B, and FIG. 2 is formed in the head adjoining part of the bore wall 4.

The cooling water passages 10 have cooling water introduction portions at their lower portions as shown in FIG. 1B.

It consists of a pair of right and left riser 12 which has (13), and three crossing channels 15 provided in the upper and lower three stages so that these riser 12 may connect with each other, and the left and right cylinder jackets The cooling water in (8) is introduced from the cooling water introduction portion 13 and flows through the cooling water passage 10 to the head jacket 22 so as to strongly cool the head adjacent portion of the bore wall 4.

Hereinafter, the casting method of the multi-cylinder cylinder block having the cooling water passage 10 will be described.

In advance, the channel forming core 31 shown in FIGS. 5A and 5B is molded. 5A is a plan view of the channel forming core 31, and FIG. 5B is a front view of the channel forming core 31. FIG. The said channel formation core 31 has a shape corresponding to the said cooling water path 10, and is shape | molded by the spheroidized particle yarn mentioned later using the core mold not shown in figure.

The spheroidized particle yarns have the following characteristics.

First, a round and nearly spherical granular shape has very good fluidity and filling properties, and high strength (lateral breaking force) is obtained even with a small amount of adhesive (thermosetting resin).

Incidentally, the particle size coefficient of the normal silica sand is 1.57, whereas the particle size coefficient of the spheroidized particle sand is l.05. Moreover, in the addition amount of adhesive agent 2.2%, the lateral breaking force of normal silica sand is 78.7 Kgf / cm <2>, while the lateral breaking force of the said spheroidized particle yarn is 107.9 Kgf / cm <2>.

Secondly, since the coefficient of thermal expansion is smaller than that of ordinary silica sand, it is possible to form a high precision channel forming core without cracking or deformation. Incidentally, the thermal expansion coefficient with respect to the temperature rise of 400 ° C to 1000 ° C is l.25% in ordinary silica sand, while 0.4% in the spheroidized particle sand. Third, the sand is easy to remove because of its good decay after pouring the molten metal.

The above characteristics of the spheroidized particle yarns made it possible to form the cooling water passage 10 using the channel forming core 31 instead of the conventional sheet metal channel forming member.

Next, the channel forming core 31 is attached to each bore wall corresponding portion of the jacket forming die (not shown), and the common casting sand is pressurized and filled with a core forming machine not shown in the jacket forming die, and FIG. 4A. The cylinder jacket core 30 shown in this figure is shape | molded. In this way, the channel forming core 31 is integrated with the cylinder jacket core 30. In Fig. 4A, reference numeral 32 denotes a cylinder counterpart, 33 is a jacket connection connecting the cylinder jacket 8 and the head jacket 22, and 34 is a plug hole counterpart that also serves as a hole for discharging sand, 35a, 35b respectively shows the entrance / exit correspondence part of the cooling water to the cylinder jacket 8, and the bore correspondence part 38 of the crank bore core 36 shown in FIG. 4B in the cylinder correspondence part 32 of the said cylinder jacket core 30 is shown. Is fitted.

Next, as shown in Fig. 3, the cylinder jacket core 30, the crank bore core 36 (see Fig. 4B) and the cam balancer core in the cylinder block forming die 28. 39 and the like, and the molten metal is poured into the cavity in the cylinder block forming die 28. After the casting is cooled, sand is removed from the plug hole 25 to complete casting of the multi-cylinder cylinder block 1. In this way, the cylinder jacket 8 and the head jacket are formed on the bore wall 4 of the multi-cylinder cylinder block by the channel forming core 31.

The cooling water passage 10 connecting the 22 is formed.

As shown in FIG. 5B, the channel forming core 31 has a shape corresponding to the cooling water path 10, and has a pair of left and right rising path counters 32 and corresponding rising paths. It consists of three transverse water passage counterparts 35 provided in three stages up and down so that the 32 is continuous with each other, and a pair of left and right cooling water introduction counterparts 33 installed at the lower portion of the rising channel counterpart 32. A cavity 36 is formed between the counterparts 35 in the vertical passage.

Each cavity part 36 is for forming the connection part 4b (refer FIG. 1B) which connects the front wall part 4c of the bore wall 4 and the wall rear part 4d in FIG.

15 is separated by the connecting portion 4b. This serves as a rib for reinforcing the bore wall 4 in which the connection portion 4b forms the cooling water passage 10, and to solve the problem that the bore wall 4 is distorted during machining of the cylinder bore. will be.

As shown in FIGS. 5A and 5B, the channel forming core 31 has a cross section corresponding to the channel.

The height H of 35 is set higher than the height h of the cavity 36. This strengthens the lateral breaking force of the counterpart 35 in the crossway of the core 31 and at the same time makes the height H of each crossway 15 greater than the height H of the connecting portion 4b. By setting it high, it is intended to ensure sufficient cross-sectional area to a cooling water, while ensuring the strength which can prevent the distortion at the time of machining a cylinder bore.

Incidentally, in the above embodiment, the front and rear widths W of the counterparts 35 are set to be 2/3 or less at least 1/3 of the minimum thickness T of the wall 4 in the number of crossings, and the height ( H) is set to 2 times or more and 3 times or less of the height h of the cavities 36. For this reason, the front and rear widths W of each traverse channel 15 are set to 2/3 or less at least 1/3 of the minimum thickness T of the bore wall 4, and each traverse channel 15 The height H of the connection portion 4b is set from two times or more to three times or less of the height h of the connecting portion 4b, and the cross-sectional area of the cooling water passage 10 can be further increased to further increase the cooling effect of the bore wall 4. have.

In addition, as shown in FIG. 5A, the pair of left and right cooling water introduction counterparts 33 of the channel forming core 31 are configured to open along the cylinder outer peripheral surface 3b adjacent to each other back and forth. This forms a large opening of the cooling water introduction portion 13, so that most of the cooling water flows from the cooling water introduction portion 13 that is opened toward the cylinder jacket 8 to the cooling water.

A large amount flows into (10) to strongly cool the head adjoining portion 4a of the bore wall 4.

In addition, as shown in the imaginary line in Fig. 5A, the cross section of the channel forming core 31 has a wedge shape in which its front end is symmetrical toward the center, as shown by a virtual line in Fig. 5A. good. This makes each of the water passages 15 in a wedge shape whose front end is symmetrical toward the center, so that the bore wall 4 is made very thin. For this reason, the pitch between cylinder bores is made smaller, or the diameter of a cylinder bore is made larger, and there exists an advantage which can increase exhaust amount or can also increase output.

The bore wall 4 is formed continuously with a pair of left and right pairs of cylinder head fastening bosses 5, as shown in Figs. 1A and 1B, and the pair of left and right rising channels 12 are the boss portions. It is located inside of (5). This allows the cylinder 3 to be fastened uniformly and strongly along the circumferential direction by narrowing the interval between the head bolts 6. In addition, by connecting the bore wall 4 and the cylinder head fastening boss portion 5 continuously, the jacket connection hole 24 formed in the upper wall of the cylinder block 1 and the pair of ascending channels 12 By increasing the diameter of), there is an advantage that can distribute a large amount of cooling water.

That is, the left and right pairs of cylinder head fastening bosses 5 are continuously formed at both left and right sides of the head adjoining portion 4a, and the left and right pair of coolant introduction portions 13 are formed in the cylinder head fastening bosses ( Since it is arrange | positioned at the lower surface of 5), the opening of the said coolant introduction part 13 can be enlarged largely up and down toward the left and right cylinder jacket 8 ,. In addition, the cylinder jacket 8 has a wide width at the bottom of the cylinder head fastening boss 5 so that the coolant fluidity is good. Therefore, the coolant in the cylinder jacket 8 easily flows into the coolant introduction portion 13 that is largely opened up and down toward the cylinder jacket 8. Moreover, since the opening of the cooling water introduction portion 13 is extended back and forth along the cylinder outer circumferential surface 3b, the cooling water flows smoothly along the cylinder outer circumferential surface 3b, and the cooling water introduction portion is largely opened up and down toward the cylinder jacket 8 ( 13 and flows in a large amount, and exits through the cooling water passage 15 and the jacket connecting passage 12 to the head jacket 22 positioned above the continuous wall portion 4. In the meantime, the head adjacent portion 4a is strongly cooled. As a result, the cooling performance is significantly improved.

6A and 6B show a core for forming a channel according to a modification of the present invention, FIG. 6A is a front view of the core according to the first modification, and FIG. 6B is a front view of the core according to the second modification. In the modification of FIG. 6A, the upper edge of the counterpart 35 is formed to be inclined upward from the left and the right in each crossing, and the lower edge is formed to be inclined downward from the left and the right. Other points are comprised like the said Example (FIG. 5). This causes the steam to move upward along the upper edge of each of the cooling water passages 15 formed inclined upward, even when the cooling water is boiled in each of the cross-passages 15. Through the head jacket 22 is to go through. As a result, the cooling performance is maintained high.

In the modification of FIG. 6B, each cavity part 36 is formed in ellipse, and the other point is comprised like the said Example (FIG. 5). This is formed in the corresponding position of the cavity part 36, and forms the connection part 4b which isolate | separates each crossing channel 15 in ellipse, and makes the flow of cooling water smooth.

According to each of the above embodiments, it is possible to cool the head adjoining portion of the bore wall 4 strongly and to cool the piston ring strongly through the cylinder wall, so that the top ring is attached to the piston top surface. As close as possible, it is possible to improve the air utilization rate by making the ring-shaped dead space which does not contribute to the combustion of the outer circumference of the piston top extremely small.

In addition, it is possible to solve the fixing of the top ring by carbonization of the unburned fuel. Moreover, as the top ring is as close to the piston top as possible, the position of the piston pin can be as close to the piston top as possible, and the radius of rotation of the crankshaft can be increased by that, without changing the overall height of the connecting rod engine. It is possible to reduce the size and increase the piston stroke to increase the displacement.

In addition, since the head adjoining portion of the bore wall 4 can be strongly cooled, it is also possible to increase the displacement by increasing the diameter of the cylinder bore. In addition, even in a multi-cylinder engine or the like equipped with a turbo charger, by applying the present invention, it is possible to achieve a relatively small size and a large output of the engine. On the contrary, when the piston stroke is not changed, the connecting rod can be set as long as the position of the piston pin is made closer to the piston upper surface, so that the piston side pressure can be lowered, and as a result, the friction loss can be reduced.

In the above embodiment, the channel forming core 31 is attached to each bore wall corresponding part of the jacket forming die (not shown), and the general molding sand is pressurized and filled with a core shaping machine (not shown) in the jacket forming die. Although the method to shape the cylinder jacket core 30 was demonstrated, this invention is not limited to this. In other words, the cylinder jacket core 30 may be molded in advance by a jacket forming die, and the channel forming core 31 may be attached to the bore wall corresponding position of the jacket core 30. In short, it does not matter if the channel forming core 31 is attached to the bore wall corresponding position of the jacket core 30 before pouring the molten metal.

(a) In the invention according to claim 1, in the cylinder block of the multi-cylinder engine having the above-mentioned basic structure, between the upper and lower transverse channels 15, the first wall part 4c of the bore wall 4 and the second wall part 4d Since the upper and lower cross channel 15 is formed by forming the connecting portion 4b for connecting the upper and lower sections, the jacket core due to the difference in expansion ratio, which is a drawback of the conventional example of casting and inserting a channel forming member made of sheet metal, is formed. This can eliminate cracks and deformations.

(b) In the invention according to claim 1, the connecting portion 4b connecting the first wall portion 4c and the second wall portion 4d of the bore wall 4 reinforces the bore wall 4 having the cooling water passage 10. By functioning as a rib, it is possible to solve a problem such that the bore wall is distorted during machining of the cylinder bore.

(c) In the invention described in claim 1, since the channel forming member of the sheet metal is not interposed, the problem of peeling the channel forming member is eliminated, and the cooling effect of the bore wall can be improved.

(d) In the invention according to claim 1, since the height H of each cross channel 15 is set higher than the height h of the connecting portion 4b, the strength that can prevent distortion during machining of the cylinder bore. It is possible to secure a sufficient cross-sectional area of the cooling water passage while ensuring

(e) In the invention according to claim 2, in the cylinder block of the multi-cylinder engine according to claim 1, the width W of the front and rear of each of the traverse channels 15 is determined by the minimum thickness T of the bore wall 4. The height H of each cross channel 15 is set from two times or more to three times or less of the height h of the connecting portion 4b. Therefore, the cross-sectional area of the cooling water path can be further increased to further increase the cooling effect of the bore wall.

(f) In the invention described in claim 3, in the cylinder block of the multi-cylinder engine according to claim 1 or 2, the left and right both sides of the pair of left and right cylinder head fastening bosses 5 are attached to the head adjacent portions 4a. It is formed continuously to the left and right pair of coolant introduction portion

Since 13 is disposed close to the lower surface of the cylinder head fastening boss 5, the opening of the cooling water introduction portion 13 can be enlarged up and down largely toward the left and right cylinder jackets 8. In addition, under the cylinder head fastening boss 5, the width of the cylinder jacket 8 is wide, and fluidity of the cooling water is also good. Therefore, the coolant in the cylinder jacket 8 easily flows into the coolant introduction portion 13 that is largely opened up and down toward the cylinder jacket 8. Moreover, since the opening of the cooling water introduction portion 13 opens back and forth along the cylinder outer circumferential surface 3b, the cooling water flows smoothly along the cylinder outer circumferential surface 3b, and the cooling water introduction portion is largely opened up and down toward the cylinder jacket 8. A large amount flows in from (13) and goes out to the head jacket 22 located above the continuous wall portion 4 through the cooling water passage 15 and the jacket connecting passage 12. In the meantime, the head adjacent portion 4a is strongly cooled. As a result, the cooling performance is significantly improved.

(g) In the invention according to claim 4, in the casting method of the multi-cylinder cylinder block having the basic structure, the cylinder jacket 8 and the head jacket at the head adjacent portion of the bore wall 4 of the multi-cylinder engine E. Since the channel forming core 31 for forming the cooling water path 10 connecting the 22 is formed from spherical particles having a lower expansion rate than that of ordinary silica sand, the spheroidized particles have very good fluidity and filling properties, and less adhesive. Since the core for forming a channel having a large lateral breaking force can be formed even by the addition of the above, it is possible to form a highly precise cooling water channel.

That is, if the core for forming a channel is formed by a conventionally used non-spherical casting sand, the spacing between the casting sand particles is large in the non-spherical casting sand, so the filling ability is poor and the shape holding force of the casting sands is weak, so that the shape holding force of the casting sands is weak. In order to secure the required lateral breaking force, it is necessary to increase the adhesive content of the foundry sand. On the other hand, in the channel forming core with a high content of the adhesive, the amount of gas generated by the evaporation of the adhesive increases during the pouring of the molten metal, so that a cavity is likely to be generated in the gap between the gas evaporation sites.

In addition, when the core for forming a channel having a smaller mass and a lower heat capacity than other parts is formed of a conventional non-spherical casting sand, the shape holding force is extremely low due to evaporation scattering of the adhesive. May cause the shape to break, and furthermore, no channel is formed, or so-called "molding sand residue". As a result, unnecessary castings may be formed on the inner surface of the channel by casting sand included in the casting or by casting of the casting sand on the casted surface, thereby narrowing the channel, and furthermore, cooling by accumulating scales on the inner surface of the channel. It causes a decrease in performance.

On the other hand, in the present invention, since the channel forming core 31 is formed of spherical particles having a lower expansion ratio than that of ordinary silica sand, the spheroidized particles can secure the shape holding force and the transverse breaking force of the mold with less adhesive content. At the same time, it is also possible to prevent casting sand from burning to the casting. That is, since the space | interval between sand particle | grains becomes small, filling property becomes largely favorable and the shape holding force of casting sand becomes strong. Therefore, it becomes possible to significantly reduce the adhesive content to secure the shape holding force of the casting threads and the required lateral breaking force. As a result, even if the adhesive content is 2.5% by weight, the lateral breaking force is increased, and a high-strength channel forming core having a lateral breaking force of 150 kgf / cm 2, which has been difficult with conventional non-spherical casting sands, can be formed. In other words, even if the adhesive content is significantly reduced, sufficient shape holding force and lateral breaking force can be ensured.

The channel 31 for forming the channel formed by the spheroidized particle yarn has a small content of the adhesive, so that a small amount of gas is generated by the evaporation of the adhesive during the injection of molten metal, and a gap or a cavity is generated in the gas evaporation site. The case disappears. In addition, even if the adhesive is evaporated and scattered, the shape holding force of the casting sands is strong, so that the mold is not broken and so-called "molding sand residue" does not occur. Therefore, it is difficult to produce the casting sand in the casting or the casting sand is attached to the casting surface by burning, and the disadvantage of narrowing the channel and the accumulation of scale are also eliminated. In other words, by using a core for forming a channel, which is formed by spherical particles and has a large transverse breaking force and is hard to be broken, a high-precision cooling water channel can be formed.

(h) In the invention according to claim 4, the channel forming core 31 is attached to the bore wall corresponding position of the jacket core 30 before the molten metal is poured. Cooling water passage 10 is formed. For this reason, the crack and deformation | transformation of the core for a jacket resulting from the difference of the expansion rate which are the drawbacks of the conventional example which casts and puts the channel forming member made of sheet metal into a channel can be eliminated.

(i) In the invention according to claim 4, since the channel forming member of the sheet metal is not interposed, the problem that the channel forming member is peeled off is eliminated, and as long as the channel forming member of the sheet metal is not interposed, Since the cross-sectional area can be increased, the cooling effect of the bore wall can be further enhanced.

1 shows a cylinder block of a multi-cylinder engine according to an embodiment of the present invention, FIG. 1A is a partial plan view of the cylinder block, and FIG. 1B is a longitudinal sectional view of a coolant path formed in a bore wall which is a main portion of the cylinder block.

Fig. 2 is a longitudinal sectional view of the main portion of a vertical multicylinder engine having a cooling water passage according to the present invention.

Fig. 3 is a longitudinal sectional view of a main portion showing a state in which a cylinder jacket core, a crank bore core, or the like is mounted in a cylinder block forming die.

4A is a perspective view of a cylinder jacket core according to the present invention, and FIG. B is a perspective view of a crank bore core.

5 shows a channel forming core according to the present invention, FIG. 5A is a plan view of the channel forming core, and FIG. 5B is a front view of the channel forming core.

6 shows a channel forming core according to another embodiment of the present invention, FIG. 6A is a front view of the core according to the first modification, and FIG. 6B is a front view of the core according to the second modification.

FIG. 7 is a diagram corresponding to FIG. 1B according to the prior art. FIG.

8 is a diagram corresponding to FIG. 4A according to the prior art.

Fig. 9 shows a channel forming member of sheet metal according to the prior art, Fig. 9A is a perspective view of the sheet metal forming channel, and Fig. 9B is a plan view showing a state in which a molding sand is filled in the channel forming member, and Fig. 9C shows the channel. It is a front view which shows the state which filled the molding sand with the formation member.

Claims (14)

A cylinder block of a multi-cylinder engine, comprising a cooling water passage (10) formed in a head adjacent portion of a cast metal bore wall, The cooling water channel 10 includes a plurality of vertically adjacent crossing channels 15 and 15 formed in multiple stages up and down, The connecting wall portion 4b is formed by at least one cast metal connecting wall, which connects the first wall portion 4c and the second wall portion 4d of the bore wall 4 with a vertically adjacent traverse number. Disposed between the furnaces 15 and 15, thereby separating the vertically adjacent transverse waterways 15 and 15 from each other, The cooling water channel 10 causes the surface of the cast metal wall facing the waterway space to be entirely exposed as the cast surface, The cooling water channel 10 further includes a pair of left and right rising channels 12 and 12 having cooling water introduction portions 13 and 13 at the lower portion thereof, and the crossing channels 15 and 15 are the rising channel ( 12, 12 are communicated with each other, and the right and left cylinder jackets 8, 8 of the cylinder block are circulated, and the cooling water introduced into the cooling water introduction parts 13, 13 flows into the cooling water path 10, and then rises. Going upwards from the cylinder block through the channel 12, a head jacket located above the cylinder block receives the coolant from the rising channel 12, The pair of left and right cylinder head fastening bosses 5 and 5 has a lower surface, is integrated with adjacent cylinder walls 3 and 3 and at the same time head adjacent portions 4a of the bore wall 4. Is located in both left and right sides of the The cooling water introduction portions 13 and 13 are disposed close to the lower surface of the fastening bosses 5 and 5 and extend from the lower edge of the boss portions 5 and 5 to the lower edge of the cross channel 15. A cylinder block of a multi-cylinder engine that extends over an entire upper and lower direction and extends back and forth along adjacent cylinder jackets (8, 8) of the cylinder block. The method of claim 1, The cylinder of the multi-cylinder engine in which the cast surface of the wall of the cooling water passage 10 is not covered with a channel forming member made of a metal plate, but is formed by a metal cast around the channel forming core 31 made of spherical particles. block. The method of claim 1, The cast surface of the coolant passage 10 forms part of the cylinder jacket 8 wall surface of the cylinder block, and of the cast surfaces of the cylinder jacket 8, only the cast surface of the coolant passage 10 is a metal plate. A cylinder block of a multi-cylinder engine, which is not covered with a channel forming member made of metal, and is formed of a metal cast along a channel 31 for spheroidizing particle yarns. The method of claim 2, The cylinder block of the multicylinder engine in which the height H of each said crossing channel 15 is set larger than the height h of the said connection wall part 4b. The method of claim 2, The front and rear widths W of each of the traverse channels 15 are set to not less than 2/3 of the minimum thickness T of the bore wall 4 and not more than 2/3 of each of the traverse channels 15. A cylinder block of a multi-cylinder engine, in which a height (H) is set to not less than two times but not more than three times the height (h) of the connecting wall portion (4b). A cylinder block of a multi-cylinder engine, comprising a cooling water passage (10) formed in a head adjacent portion of a cast metal bore wall, The cooling water channel 10 includes a plurality of vertically adjacent crossing channels 15 and 15 formed in multiple stages up and down, The connecting wall portion 4b is formed by at least one cast metal connecting wall, which connects the first wall portion 4c and the second wall portion 4d of the bore wall 4 with a vertically adjacent transverse channel. Disposed between (15, 15), thereby separating the vertically adjacent transverse waterways (15, 15) from each other, The cooling water passage 10 allows the surface of the cast metal wall facing the waterway space to be entirely exposed as the cast surface, The front and rear widths W of the respective crossing channels 15 are set to not less than 2/3 at least one third of the minimum thickness T of the bore wall 4, and A cylinder block of a multi-cylinder engine, in which a height (H) is set to not less than two times but not more than three times the height (h) of the connecting wall portion (4b). The method of claim 6, A cylinder block of a multi-cylinder engine, in which the cast surface of the cooling water passage (10) is not covered with a channel forming member made of a metal plate, but is formed of a metal cast around a channel forming core (31) of spherical particles. The method of claim 6, The cast surface of the cooling water passage 10 forms part of the wall surface of the cylinder jacket 8 of the cylinder block, and of the molded surfaces of the cylinder jacket 8, only the cast surface of this cooling water passage 10 is a metal plate. A cylinder block of a multi-cylinder engine, which is not covered with a channel forming member made of metal and is formed of a metal cast along a channel 31 for spheroidizing particles. The method of claim 7, wherein The cooling water channel 10 further includes a pair of left and right rising channels 12 and 12 having cooling water introduction portions 13 and 13 at the lower portion thereof, and the crossing channels 15 and 15 are the rising channel. (12, 12) are communicated with each other, the inside of the cylinder jacket on the left and right of the cylinder block flows, and the cooling water introduced into the cooling water introduction portions (13, 13) flows into the cooling water channel (10), and then the rising channel (12). A cylinder block of a multi-cylinder engine, which goes upwards from the cylinder block through and receives a cooling water from the ascending channel 12, wherein the head jacket positioned above the cylinder block receives the cooling water. The method of claim 2, A cylinder block of a multi-cylinder engine using spherical particles of thermal expansion lower than ordinary silica sand. In the method of manufacturing the cylinder block of the multi-cylinder engine according to claim 1, A core 30 is formed for forming the jacket 8 of the multicylinder engine E, and the molten metal is formed in a mold 28 for forming the cylinder block, which is poured to cast a cylinder block for the multicylinder engine E. The core 30 is attached; The channel forming core 31 made of spherical particles is fixed to a position corresponding to the inner bore wall of the jacket core 30 before pouring the molten metal without being covered with the channel forming member made of a metal plate;  The cooling water channel (10) is provided, and the casting surface of the wall is formed by the metal cast around the channel forming core (31) made of spherical particles without being covered by the channel forming member formed of a metal plate; And The cooling water passage (10) is provided with a casting wall, the surface of the cylinder block manufacturing method for a multi-cylinder engine facing the totally open internal space, such as the cast surface. The method of claim 11, To ensure that each cross channel has a height greater than the height of the connecting portion 4b; The height H of the counterpart 35 of the channel forming core 31 is set to be larger than the height h of the hollow part 36 between the counterparts 35 corresponding to the vertically adjacent traversal channel. Cylinder block manufacturing method for a cylinder engine. The method of claim 11, The front and rear widths W of each traverse channel 15 are set to 2/3 or less at least 1/3 of the minimum thickness T of the inner bore wall 4, and To set the height H from 2 times or more to 3 times or less than the height h of the connecting portion 4b; The front and rear width W of the counterpart 35 corresponding to each cross channel of the channel forming core is set to not less than 1/3 but not more than 2/3 of the minimum thickness T of the inner bore wall 4. The height H of the corresponding part 35 corresponding to each cross channel is twice the height h of the hollow part 36 between the corresponding parts 35 corresponding to the vertically adjacent cross channel. Cylinder block manufacturing method for a multi-cylinder engine set to three times or less above. The method of claim 11, A method for producing a cylinder block for a multi-cylinder engine using spherical particles of thermal expansion lower than that of ordinary silica sand.