JP5521868B2 - Cylinder block and cylinder block manufacturing method - Google Patents

Description

  The present invention relates to a cylinder block for an internal combustion engine and a method for manufacturing the same, and more particularly to a cylinder block in which an accommodation space for a timing chain is integrally formed and a method for manufacturing the same.

  In an internal combustion engine (engine) mounted on a vehicle or the like, a timing chain is used to transmit rotation of a crankshaft to a camshaft. The timing chain is also referred to as a box-shaped accommodation space (“chain case”) in order to protect the timing chain and to prevent the lubricating oil (oil) that facilitates power transmission from scattering to the outside. ). Conventionally, by attaching a separate chain cover to the cylinder block direction of the cylinder block and the cylinder head, that is, one side (engine front side) in the direction in which the crankshaft extends, a chain case is formed that opens upward and downward. The timing chain was accommodated in this chain case.

  However, recently, as a cylinder block of an internal combustion engine, for example, as shown in Patent Documents 1 and 2, a cylinder block in which a chain case is integrally formed (also referred to as a “chain case integrated cylinder block”). Is also known. A cylinder block integrated with a chain case is manufactured, for example, by die-casting aluminum alloy or the like. During casting, the mold case (mold) is die-cut (casted) up and down, and the chain case is removed. Molded.

JP 2005-344699 A Japanese Utility Model Publication No. 7-17936

  However, the conventional chain case-integrated cylinder block has a problem that casting defects such as shrinkage are likely to occur. Specifically, since the outer wall forming the chain case is provided on the engine front side, it has been difficult to cast from the engine front side when casting the cylinder block. For this reason, the wall part provided between the water jacket formed around the cylinder and the chain case may be thickened. Specifically, there is a possibility that a region below the female screw hole to which the head bolt is tightened may be thickened, which may cause a casting defect such as a shrinkage cavity to occur easily. In addition, there has been a concern that so-called internal leakage may occur in which the oil in the main gallery (main oil hole) leaks to other parts due to such casting defects.

  The present invention has been made in view of such a problem, and an object of the present invention is to suppress the occurrence of the above-described problems due to thickening in a chain case-integrated cylinder block.

  In the present invention, means for solving the above-described problems are configured as follows. That is, the present invention is a cylinder block, in which a water jacket is formed around the cylinder, and a storage space for the timing chain is integrally formed therein. A cooling water passage is formed so as to pass through a wall portion provided between the water jacket and the accommodation space, and the cooling water passage is supplied with cooling water from a water pump and communicates with the water jacket. And a downstream passage through which cooling water flows out to the outside. The upstream passage has a cross-sectional area larger than that of the downstream passage.

  According to the above configuration, the cooling water passage is provided so as to penetrate the wall portion provided between the water jacket and the storage space of the timing chain, so that the wall portion is suppressed from being thickened. Thereby, in the cylinder block integrated with the chain case, it is possible to suppress the occurrence of casting defects such as shrinkage cavities due to thickening. Moreover, generation | occurrence | production of the internal leakage resulting from such a casting defect can be suppressed.

  Moreover, the cross-sectional area of the upstream passage provided on the upstream side of the cooling water flow with respect to the water jacket is made larger than the cross-sectional area of the downstream passage provided on the downstream side of the cooling water flow with respect to the communication portion. Therefore, it becomes possible to reliably supply cooling water having a flow rate necessary for cooling the cylinder block from the upstream passage to the water jacket. In addition, since the downstream passage is provided in parallel with the water jacket with respect to the upstream passage, the cooling water that has not been supplied to the water jacket flows into the downstream passage. Accordingly, since the cooling water from the upstream passage directly flows into the downstream passage, the low-temperature cooling water is supplied to various devices (for example, an oil cooler, an EGR cooler, etc.) provided outside the cylinder block. The cooling efficiency of various devices can be increased.

  In the cylinder block of the present invention, it is preferable that the cooling water passage is provided below a female screw hole to which the head bolt is tightened.

  According to the above configuration, in the cylinder block integrated with the chain case, it is possible to effectively suppress the thickening of the region below the female screw hole, which has been particularly concerned in the past. Casting defects can be effectively suppressed.

  Here, it is preferable that the cooling water passage is arranged avoiding a breathing hole provided in the cylinder block and an oil gallery. Specifically, it is preferable to arrange the cooling water passage above the breathing hole and arrange the downstream passage of the cooling water passage above the main gallery. Further, it is preferable that a deep bottom portion formed deeper than the other portions is provided in a portion of the water jacket timing chain on the accommodation space side, and the deep bottom portion communicates with the cooling water passage. .

  In the cylinder block of the present invention, the upstream side passage, the downstream side passage, and the water jacket are formed by separate molding dies, and a first molding die for molding the upstream side passage is provided. A second molding die that is die-cut to one side in the horizontal direction and molds the downstream passage is die-cut to the other side in the horizontal direction, and a third molding die that molds the water jacket is It is preferable that the upstream side passage, the downstream side passage, and the water jacket are respectively formed by being punched. More specifically, the first to third molding dies are assembled with a gap therebetween, and in this mold assembly state, the first molding dies are the third molding dies. A first gap extending in the horizontal direction is separated from a lower side of the portion for molding the deep bottom portion of the molding die of the first mold, and the first gap is formed on one side in the horizontal direction of the portion for molding the deep bottom portion. The second molding die is disposed with a second gap continuous with one end in the horizontal direction of the gap, and the second molding die is the deep bottom portion of the first molding die and the third molding die. It is preferable that a third gap continuous with the other horizontal end of the first gap is disposed on the other side in the horizontal direction of the portion for forming the mold.

  According to the above configuration, after casting the cylinder block, the first film formed at a position corresponding to the first gap is drilled so as to form a through hole from one end in the horizontal direction to the other end. Thus, the upstream side passage, the downstream side passage, and the deep bottom portion of the water jacket can be communicated with each other by one processing. That is, since the second and third films formed at positions corresponding to the second and third gaps are formed at both ends in the horizontal direction of the first film, when the first film is to be cut The second and third films are also cut together, and all of the first to third films can be penetrated by only one processing.

  In this case, a horizontally extending through hole formed by cutting the first film serves as a communication portion that connects the upstream passage and the deep bottom portion of the water jacket. Further, a through hole formed by cutting the third film serves as a communication portion that communicates the upstream side passage and the downstream side passage. And since the communication part which connects an upstream channel | path and the deep bottom part of a water jacket is formed from one end of the left-right direction of a 1st film | membrane to the other end, the opening area of this communication part is downstream from an upstream channel | path. It becomes larger than the opening area of the communicating part communicating with the side passage. As a result, various devices (for example, oil coolers, etc.) provided outside the cylinder block that require a relatively small amount of cooling water while forming a large opening area of the communication portion to the water jacket that requires a relatively large amount of cooling water. The opening area of the communication part to the EGR cooler or the like can be formed small. Accordingly, two types of communication portions corresponding to the required amount of cooling water can be formed by only one processing.

  The present invention also relates to a method of manufacturing a cylinder block in which a water jacket is formed around a cylinder, and an accommodation space of the timing chain is integrally formed therein, and the cylinder block includes the water jacket and the accommodation space. A cooling water passage is formed so as to penetrate through the wall portion provided in between, and a portion of the water jacket on the accommodation space side is provided with a deep bottom portion formed deeper than other portions, The cooling water passage includes an upstream side passage through which cooling water from the water pump flows and communicates with the deep bottom portion of the water jacket, and a downstream side passage through which the cooling water flows out to the outside. When casting, the upstream side passage, the downstream side passage, and the water jacket are separated by separate molding dies. The first molding die for forming the upstream passage is molded in one horizontal direction, and the second molding die for forming the downstream passage is used as the first molding die. The upstream side passage, the downstream side passage, and the water jacket are cut out in the direction opposite to the die release direction of the die, and the third molding die for forming the water jacket is punched upward. Are formed in the cylinder block, respectively. According to the cylinder block manufactured in this way, the same effect as the above-described cylinder block of the present invention can be obtained.

  Then, the first to third molding dies are assembled with a gap therebetween, and in this mold assembly state, the first molding dies are replaced with the third molding dies. A first gap extending in the horizontal direction is separated from the lower side of the portion for forming the deep bottom portion of the mold, and the horizontal direction of the first gap is disposed on one side of the horizontal portion of the portion for forming the deep bottom portion. The second molding die is arranged with a second continuous gap at one end of the first molding die, and the deep bottom portion of the first molding die and the third molding die is molded. The third gap is arranged on the other side in the horizontal direction with a third gap continuous to the other horizontal end of the first gap. According to the cylinder block manufactured in this way, the same effect as the above-described cylinder block of the present invention can be obtained.

  In the cylinder block manufacturing method of the present invention, after the cylinder block is cast, drilling is performed so as to form a through hole from one end in the horizontal direction to the other end of the film formed at a position corresponding to the first gap. It is preferable to carry out. Here, depending on the amount of cooling water required for the water jacket and various devices provided outside the cylinder block, the diameter of the drill used for the drilling and the depth of the third molding die It is preferable to set the horizontal width of the portion forming the bottom. Or it is preferable to set the diameter of the drill used for the said drilling, and the frequency | count of drilling according to the amount of cooling water requested | required by the said water jacket and the various devices provided in the exterior of a cylinder block, respectively.

  According to the present invention, since the cooling water passage is provided so as to penetrate the wall portion provided between the water jacket and the storage space of the timing chain, the wall portion is suppressed from being thickened. Thereby, in the cylinder block integrated with the chain case, it is possible to suppress the occurrence of casting defects such as shrinkage cavities due to thickening.

It is sectional drawing which shows schematic structure of the internal combustion engine provided with the cylinder block to which this invention is applied. It is a perspective view which shows schematic structure of the cylinder block of FIG. It is a perspective view which shows the cross-sectional structure of the cooling water channel | path formed in the cylinder block of FIG. FIG. 3 is a cross-sectional view taken along line X1-X1 of FIG. FIG. 3 is a cross-sectional view taken along line X2-X2 of FIG. FIG. 3 is a cross-sectional view taken along line X3-X3 of FIG. It is a figure which shows the state when the metal mold | die for a shaping | molding was assembled at the time of casting of a cylinder block, and cut | disconnected by the line | wire equivalent to the X4-X4 line | wire of FIG. It is a figure which shows the state when the molten metal was supplied in the cavity formed with the metal mold | die for a mold after the state of FIG. 7, and cut | disconnected by the line | wire equivalent to the X4-X4 line | wire of FIG. It is a figure which shows the state when the metal mold | die for shaping | molding was cut out after the state of FIG. 8, and cut | disconnected by the line corresponded to the X4-X4 line | wire of FIG. FIG. 10 is a diagram showing a state in which processing for penetrating a cooling water passage is performed after the state of FIG. 9, and shows a cross section when cut along a line corresponding to line X 4 -X 4 of FIG. 2.

  Embodiments of the present invention will be described with reference to the accompanying drawings.

  First, a schematic configuration of an internal combustion engine including a cylinder block to which the present invention is applied will be described. In FIG. 1, an inline 4-cylinder engine 1 is illustrated as an internal combustion engine.

  As shown in FIG. 1, the engine 1 includes a cylinder block 10 and a cylinder head 50. The cylinder head 50 is disposed above the cylinder block 10 and fastened to the cylinder block 10 with a head bolt (not shown). A head cover 60 is fixed to the upper part of the cylinder head 50. An oil pan 70 is provided at the lower part of the cylinder block 10.

  As shown in FIGS. 1 and 2, the cylinder block 10 is integrally formed with a block main body 11 in which a plurality of (four in this example) cylinders 12 are provided and an outer wall 30 that forms an accommodation space 31 of the timing chain 41. It has been configured. The outer wall 30 is provided on one side (engine front side) of the cylinder block 10 in the cylinder row direction. The cylinder block 10 is manufactured, for example, by die casting such as an aluminum alloy.

  The block body 11 of the cylinder block 10 is provided with a water jacket 13 around each cylinder 12. The top surface of the water jacket 13 is opened upward. The water jacket 13 communicates with a head-side water jacket formed inside the cylinder head 50.

  A piston 14 is inserted into each cylinder 12 so as to be able to reciprocate. The piston 14 is connected to the crankshaft 16 via a connecting rod 15. The direction in which the piston 14 reciprocates is the vertical direction (z-axis direction in FIG. 2), and the direction perpendicular to the vertical direction and the cylinder row direction (x-axis direction in FIG. 2) is the horizontal direction (FIG. 2). Y-axis direction).

  The crankshaft 16 is rotatably supported at the lower end portion of the cylinder block 10. Specifically, as shown in FIG. 1, a partition wall 17 for rotatably supporting the journal portion 16a of the crankshaft 16 is provided below the cylinders 12 of the block body 11 at predetermined intervals in the cylinder row direction. Separately provided. A crank cap 18 is attached to the lower surface of the partition wall 17 with a bolt or the like, and the journal portion 16 a of the crankshaft 16 is sandwiched between the partition wall 17 and the crank cap 18. A metal 19 serving as a sliding bearing is interposed between the partition wall 17 and the crank cap 18 and the journal portion 16a. Further, a crank pin 16b and a balance weight 16c of the crankshaft 16 are arranged in a facing space between the adjacent partition walls 17 and 17, that is, in the crank chamber 20.

  A crank sprocket 22 and an oil pump sprocket 23 for driving an oil pump (not shown) are integrally attached to one end of the crankshaft 16 (left end in FIG. 1). A crank pulley 25 is attached to one end of the crankshaft 16 for driving auxiliary equipment (not shown). As shown in FIGS. 2 and 5, female screw holes 26 into which head bolts for fastening the cylinder head 50 are screwed are formed at a plurality of locations of the block main body 11.

  As shown in FIGS. 1, 3, and 4, the block body 11 is provided with a breathing hole 21 for relaxing a pressure change in the crank chamber 20 due to the reciprocating motion of the piston 14. The breathing hole 21 is provided above the portion of the partition wall 17 that supports the journal portion 16a. The breathing hole 21 is formed so as to penetrate in the thickness direction of the partition wall 17. The adjacent crank chambers 20, 20 communicate with each other through the breathing hole 21, and the crank chamber 20 of the first cylinder (cylinder arranged closest to the engine front side) and the accommodation space 31 of the timing chain 41 communicate with each other. Has been. When a pressure difference occurs between the crank chambers 20 of each cylinder 12 as the piston 14 reciprocates, the pressure difference is reduced by moving the gas from the higher pressure side to the lower pressure side through the breathing hole 21. It has become so.

  In this embodiment, since four cylinders 12 are provided in series in the block main body 11, four breathing holes 21 are provided in the block main body 11. Specifically, the breathing hole 21 is provided in the partition wall 17 between the adjacent cylinders 12 and the partition wall 17 provided between the water jacket 13 and the accommodation space 31 of the timing chain 41. The four breathing holes 21 have the same shape (for example, a circle) and are arranged on the same straight line along the cylinder row direction.

  As shown in FIGS. 3 and 4, the block main body 11 is formed with a main gallery (main oil hole) 24 through which oil pumped by an oil pump is circulated. The oil whose pressure has been increased by the oil pump is supplied to the lubricated portion of the engine 1 through the main gallery 24. The main gallery 24 extends along the cylinder row direction. The main gallery 24 is provided above the breathing hole 21.

  As shown in FIG. 2, the outer wall 30 of the cylinder block 10 includes a plate-like outer wall portion 32 arranged to face the block main body 11, and a pair of plate-like connecting portions that connect the block main body 11 and the outer wall portion 32. 33, 33. The outer wall portion 32 has a shape in which a cross-sectional shape cut by a plane orthogonal to the vertical direction extends in the horizontal direction. The outer wall portion 32 is connected to a connecting portion 33 extending in a direction orthogonal to the outer wall portion 32 at both ends in the left-right direction. Each connecting portion 33 has a cross-sectional shape cut along a plane perpendicular to the vertical direction so that it extends in the cylinder row direction.

  Such an outer wall 30 is integrally provided on the engine front side of the block main body 11, thereby forming an accommodation space 31 for the timing chain 41. The housing space 31 is formed by punching the molding die in the upper and lower directions when the cylinder block 10 is cast. As shown in FIG. 1, the accommodation space 31 is a space opened up and down, and communicates with the accommodation space 51 of the timing chain 41 provided in the cylinder head 50. The timing chain 41 is accommodated in accommodation spaces 31 and 51 formed across the cylinder block 10 and the cylinder head 50.

  Here, a timing chain driving mechanism for driving the timing chain 41 will be described. As shown in FIG. 1, the cylinder head 50 is provided with an intake camshaft 52. At one end of the intake camshaft 52, an intake cam sprocket 53 is provided integrally with the rotation. A crank sprocket 22 is provided at one end of the crankshaft 16 so as to rotate integrally. The timing chain 41 is wound around the intake cam sprocket 53 and the crank sprocket 22. The timing chain 41 transmits the driving rotation of the crank sprocket 22 to the intake cam sprocket 53, thereby driving the valve gear. The timing chain drive mechanism is provided with a chain tensioner device and a chain guide (not shown). The chain tensioner device is arranged on the slack side of the timing chain 41, and the chain guide is arranged on the tight side of the timing chain 41.

  In this embodiment, as shown in FIGS. 3 and 4, the cylinder block 10 is provided with a cooling water passage 80 penetrating the block body 11 in the left-right direction. Hereinafter, the structure of the cooling water passage 80 will be described in detail. FIG. 4 shows a cut surface of the block main body 11 of FIG.

  As shown in FIGS. 2 to 6, the cooling water passage 80 is provided in the wall 11 a provided in the block body 11 between the water jacket 13 and the accommodation space 31 of the timing chain 41. That is, the cooling water passage 80 is provided in the wall portion 11 a (on the engine front side) closest to the accommodation space 31 of the block body 11.

  As shown in FIG. 4, one end (right end in FIG. 4) of the cooling water passage 80 is a cooling water introduction port 81 that introduces cooling water from a water pump (not shown) into the cooling water passage 80. The other end (left end in FIG. 4) of the cooling water passage 80 is a cooling water outlet 82 through which the cooling water in the cooling water passage 80 flows out. The cooling water flowing out from the cooling water outlet 82 is supplied to various devices (for example, an oil cooler, an EGR cooler, etc.) (not shown) provided outside the cylinder block 10. That is, the cooling water outlet 82 serves as a cooling water supply port to various devices.

  More specifically, the cooling water passage 80 is configured by connecting an inlet side passage 83 on the cooling water inlet 81 side and an outlet side passage 84 on the cooling water outlet 82 side. The inlet side passage 83 extends from the coolant introduction port 81 toward the other side in the left-right direction (left side in FIG. 4), and communicates with the outlet side passage 84 at the other end. The outlet side passage 84 extends from the cooling water outlet 82 toward one side in the left-right direction (the right side in FIG. 4), and communicates with the inlet side passage 83 at one end thereof. The communication portion 85 between the inlet-side passage 83 and the outlet-side passage 84 is located closer to the coolant outlet 82 than the central position in the left-right direction of the block body 11. The length of the inlet-side passage 83 in the left-right direction is made larger than the length of the outlet-side passage 84 in the left-right direction. The communication part 85 is formed by drilling, for example. In addition, in FIG. 4, the process trace of the communication part 85 by drilling is shown with the dashed-dotted line.

  As shown in FIGS. 5 and 6, the inlet-side passage 83 has a substantially rectangular cross-sectional shape. The outlet side passage 84 has a substantially circular cross-sectional shape. As shown in FIG. 4, the entrance-side passage 83 is provided with a step portion 83 c in the left-right direction, and the cross-sectional area of the entrance-side passage 83 changes in the left-right direction. Then, the cross-sectional area of the communication portion 85 side (the left portion of the step portion 83c) 83b rather than the cross-sectional area of the inlet-side passage 83 on the cooling water inlet 81 side (the right portion of the step portion 83c) 83a. Has been made smaller. The cross-sectional area of the outlet-side passage 84 is made smaller than the cross-sectional area of the portion 83 b on the communication portion 85 side of the inlet-side passage 83.

  As shown in FIG. 5, the cooling water passage 80 is provided below the female screw hole 26 for the head bolt. In addition, as shown in FIG. 4, the cooling water passage 80 is disposed avoiding the breathing hole 21 and the main gallery 24. Specifically, as shown in FIGS. 4 and 6, the inlet-side passage 83 is provided above the breathing hole 21. As shown in FIG. 4, the outlet side passage 84 is provided above the main gallery 24. More specifically, as shown in FIG. 5, the upper end 83 e of the inlet side passage 83 and the upper end 84 a of the outlet side passage 84 are located below the female screw hole 26. Further, as shown in FIG. 4, the lower end 83 f of the inlet-side passage 83 is located above the breathing hole 21 and at substantially the same height as the main gallery 24. The lower end 84 b of the outlet side passage 84 is located above the breathing hole 21 and the main gallery 24. Further, the left end 83 g of the inlet side passage 83 is located to the right of the main gallery 24 and to the left of the breathing hole 21. The right end 84 c of the outlet side passage 84 is located to the left of the main gallery 24 and to the right of the breathing hole 21.

  As shown in FIGS. 4 and 6, the inlet side passage 83 communicates with a water jacket 13 provided around each cylinder 12. Specifically, as shown in FIG. 6, a deep bottom portion formed deeper in the portion on the engine front side of the water jacket 13, that is, in the portion on the accommodation space 31 side of the timing chain 41 than in the other portions. 13a is provided. As shown in FIG. 4, the lower end 13 b of the deep bottom portion 13 a is located below the upper end 83 e of the inlet side passage 83 and the upper end 84 a of the outlet side passage 84. Further, the lower end 13 b of the deep bottom portion 13 a is located above the lower end 83 f of the inlet side passage 83 and the lower end 84 b of the outlet side passage 84. The left end 83g of the inlet side passage 83 extends to substantially the same position as the left end 13c of the deep bottom portion 13a.

  In this embodiment, the deep bottom portion 13 a is provided above the portion 83 b on the communication portion 85 side of the inlet side passage 83, and the lower end portion of the deep bottom portion 13 a and the portion 83 b on the communication portion 85 side of the inlet side passage 83. Are communicated with each other via a communication part 86. That is, by making the height of the upper surface of the portion 83b on the communication portion 85 side of the inlet side passage 83 lower than the height of the upper surface of the portion 83a on the cooling water inlet 81 side, the portion 83b on the communication portion 85 side is deepened. It arrange | positions under the bottom part 13a. The communication part 86 serves as a cooling water supply port to the water jacket 13. The communication part 86 is formed by drilling, for example. The opening area of the communication part 86 is larger than the opening area of the communication part 85. In addition, in FIG. 4, the process trace of the communication part 86 by drilling is shown with the dashed-dotted line.

  When the cooling water sent from the water pump is introduced into the cooling water passage 80 via the cooling water introduction port 81, the cooling water flows through the inlet-side passage 83 of the cooling water passage 80 and then the deep bottom portion of the water jacket 13. 13a and the outlet side passage 84 are branched. The cooling water flowing through the inlet side passage 83 flows out to the deep bottom portion 13 a of the water jacket 13 through the communication portion 86 and flows out to the outlet side passage 84 through the communication portion 85.

  The cooling water that has flowed into the deep bottom portion 13 a of the water jacket 13 through the communication portion 86 is supplied to the water jacket 13 around the cylinder 12. Then, the block body 11 is cooled by the cooling water flowing through the cooling water passage 80 and the cooling water supplied to the water jacket 13 via the communication portion 86. In this case, in the cooling water passage 80, the cross-sectional area of the inlet-side passage 83 provided on the upstream side of the cooling water flow from the communication portion 86 with the deep bottom portion 13 a of the water jacket 13 is smaller than that of the communication portion 86. Is larger than the cross-sectional area of the outlet side passage 84 provided on the downstream side, so that it is possible to reliably supply cooling water having a flow rate necessary for cooling the block body 11 from the inlet side passage 83 to the water jacket 13. become.

  On the other hand, the cooling water that has flowed into the outlet side passage 84 via the communication portion 85 is supplied to various devices other than the cylinder block 10 and the cylinder head 50 via the cooling water outlet 82. In this case, since the outlet side passage 84 is provided in parallel with the water jacket 13 with respect to the inlet side passage 83, cooling water that has not been supplied to the water jacket 13 flows into the outlet side passage 84. Therefore, since the cooling water from the inlet side passage 83 flows directly into the outlet side passage 84, low temperature cooling water can be supplied to various devices provided outside the cylinder block 10, and cooling of the various devices can be performed. Efficiency can be increased.

  Further, as described above, since the cooling water passage 80 is provided so as to penetrate the wall portion 11a provided between the water jacket 13 and the accommodating space 31 of the timing chain 41, the chain case integrated cylinder block 10, the occurrence of casting defects such as shrinkage can be suppressed. In this embodiment, since the cooling water passage 80 is provided below the female screw hole 26, the region below the female screw hole 26 is prevented from being thickened. Therefore, it is possible to suppress the occurrence of casting defects such as shrinkage cavities due to thickening in the region below the female screw hole 26. Moreover, it is possible to suppress the occurrence of internal leakage due to such casting defects, that is, the leakage of oil from the main gallery 24 to other parts.

  Next, a procedure for forming the cooling water passage 80 having the above configuration in the cylinder block 10 will be described.

  First, as shown in FIG. 7, when the cylinder block 10 is cast, a mold assembling step for assembling a molding die is performed. After the mold assembling step, as shown in FIG. 8, a supplying step of supplying a molten metal such as an aluminum alloy into the cavity formed by the molding die is performed. And after cooling of the supplied molten metal, as shown in FIG. 9, the die cutting process which die-cuts the metal mold | die for shaping | molding is performed. After this die-cutting process, as shown in FIG. 10, a machining process for penetrating the cooling water passage 80 by drilling or the like is performed on the cylinder block 10. Hereinafter, each step will be specifically described.

  7-10 has shown the cross section when cut | disconnected by the line corresponded to the X4-X4 line | wire of FIG. 7 and 8 show only the first to third molding dies 110, 120, and 130 and their peripheral portions, and FIGS. 9 and 10 show the first to third molding dies 110. , 120 and 130, only the concave portion of the cylinder block 10 and its peripheral portion are shown.

  First, in the mold assembling step, as shown in FIG. 7, the first to third molding dies 110, 120, and 130 are used to form the cooling water passage 80 in the cylinder block 10. Specifically, a first molding die 110 that molds the inlet-side passage 83 of the cooling water passage 80, a second molding die 120 that molds the outlet-side passage 84 of the cooling water passage 80, and water A third molding die 130 for molding the jacket 13 is used.

  The first molding die 110 has a shape corresponding to the inlet side passage 83 of the cooling water passage 80. The first molding die 110 has a substantially rectangular cross-sectional shape when cut along a plane orthogonal to the left-right direction, and has a step shape in the middle of the left-right direction. The cross-sectional area of the first molding die 110 changes in the left-right direction, and the cross-sectional area of the right portion 111 is larger than the cross-sectional area of the left portion 112.

  Specifically, the lower surface 113 of the first molding die 110 is a flat surface without a step. On the other hand, a stepped portion 114 is provided on the upper surface of the first molding die 110 in the middle in the left-right direction. The width in the vertical direction of the first molding die 110 is larger in the left portion 112 of the step portion 114 than in the right portion 111 of the step portion 114. The width in the cylinder row direction of the first molding die 110 is substantially constant from one end to the other end in the left-right direction.

  The second molding die 120 has a shape corresponding to the outlet side passage 84 of the cooling water passage 80. The second molding die 120 has a substantially circular cross-sectional shape when cut along a plane orthogonal to the left-right direction. The cross-sectional area of the second molding die 120 is substantially constant from one end to the other end in the left-right direction. The cross-sectional area of the second molding die 120 is smaller than the cross-sectional area of the first molding die 110.

  The third molding die 130 has a shape corresponding to the water jacket 13. In FIG. 7, only the engine front side portion 131 of the third molding die 130 is shown. A lower portion 131 a of the engine front side portion 131 of the third molding die 130 has a shape corresponding to the deep bottom portion 13 a of the water jacket 13. The lower surface 132 of the engine front side portion 131 of the third molding die 130 is provided so as to protrude downward from the lower surface 133 (shown by a two-dot chain line in FIG. 7) of the other portions. The lateral width of the lower surface 132 of the engine front side portion 131 of the third molding die 130 is substantially the same as the lateral width of the left portion 112 of the stepped portion 114 of the first molding die 110. Has been.

  As shown in FIG. 7, the first to third molding dies 110, 120, and 130 are assembled (positioned) in a mold-matched state. At this time, the first to third molding dies 110, 120, and 130 are assembled in a state where a gap is provided between them in order to avoid mutual abutment.

  Specifically, the left portion 112 of the first molding die 110 is disposed below the engine front side portion 131 of the third molding die 130 with a first gap C1 therebetween. . That is, the first gap C <b> 1 is provided between the upper surface 115 of the left portion 112 of the first molding die 110 and the lower surface 132 of the engine front side portion 131 of the third molding die 130. It is done. The first gap C1 is a space extending in the left-right direction and the cylinder row direction.

  Further, the right portion 111 of the first molding die 110 is disposed on the right side of the third molding die 130 with a second gap C2 therebetween. That is, the second gap C2 is formed between the step surface 116 of the step 114 of the first molding die 110 and the right side surface 134 of the engine front side portion 131 of the third molding die 130. Provided. The second gap C2 is a space extending in the vertical direction and the cylinder row direction. The second gap C2 is provided continuously at the right end of the first gap C1. In this manner, L-shaped gaps are formed by the first and second gaps C1 and C2 in the mold matching portions of the first and third molding dies 110 and 130.

  The second molding die 120 is disposed on the left side of the engine front side portion 131 of the first molding die 110 and the third molding die 130 with a third gap C3 therebetween. That is, the right end surface 121 of the second molding die 120, the left end surface 117 of the first molding die 110, and the left side surface 135 of the engine front side portion 131 of the third molding die 130. A third gap C3 is provided between them. The third gap C3 is a space extending in the vertical direction and the cylinder row direction. The third gap C3 is provided continuously at the left end of the first gap C1. In this way, T-shaped gaps are formed by the first and third gaps C1 and C3 in the mold matching portions of the first to third molding dies 110, 120, and 130.

  In the mold assembly state of FIG. 7, the upper surface 118 of the right portion 111 of the first molding die 110 and the upper surface 122 of the second molding die 120 are at substantially the same height position. . The left end surface 117 of the first molding die 110 and the left side surface 135 of the engine front side portion 131 of the third molding die 130 are at substantially the same left-right position. Further, the first molding die 110 is disposed above the breathing hole 21 (indicated by a two-dot chain line in FIG. 7) formed in the block main body 11. The second molding die 120 is disposed above the main gallery 24 (indicated by a two-dot chain line in FIG. 7) formed in the block body 11. The first and second molding dies 110 and 120 are disposed below a female screw hole 26 for a head bolt formed in the block body 11 (not shown in FIG. 7, see FIG. 5).

  Then, as shown in FIG. 7, after assembling the first to third molding dies 110, 120, and 130, a molten metal supply process is performed. In this supplying step, as shown in FIG. 8, a molten metal such as an aluminum alloy is supplied and poured into the cavity to be filled. At this time, the molten metal is also supplied to the first to third gaps C1, C2, and C3. Then, after the molten metal is cooled, the first to third molding dies 110, 120, and 130 are die-cut as shown in FIG.

  The die-cutting direction of the first molding die 110 is one in the horizontal direction (here, the right side) as indicated by Y1 in FIG. The inlet side passage 83 of the cooling water passage 80 is formed in the cylinder block 10 by punching the first molding die 110 to the right. The die-cutting direction of the second molding die 120 is the other in the horizontal direction (here, left) as indicated by Y2 in FIG. The outlet side passage 84 of the cooling water passage 80 is formed in the cylinder block 10 by punching the second molding die 120 leftward. The die-cutting direction of the third molding die 130 is upward as indicated by Y3 in FIG. The water jacket 13 is formed on the cylinder block 10 by the upward die cutting of the third molding die 130.

  Further, as shown in FIG. 9, the first film (burr) 141 is formed at a position corresponding to the first gap C1 by die cutting of the first and third molding dies 110 and 130. The first film 141 is a horizontal film having a shape extending in the left-right direction and the cylinder row direction. Similarly, the second film 142 is formed at a position corresponding to the second gap C2 by punching the first and third molding dies 110 and 130. The second film 142 is continuously provided at one end (here, the right end) in the horizontal direction of the first film 141, and is a vertical film having a shape extending in the vertical direction and the cylinder row direction. Further, the third film 143 is formed at a position corresponding to the third gap C3 by removing the first to third molding dies 110, 120, and 130. The third film 143 is continuously provided at the other horizontal end (here, the left end) of the first film 141, and is a vertical film extending in the vertical direction and the cylinder row direction.

  Next, in the machining step, as shown in FIG. 10, the first to third films 141, 142, 143 are cut by a drill or the like to penetrate the cooling water passage 80. This through-cutting process is a process in which a through-hole is formed from one end of the first film 141 in the horizontal direction to the other end. For example, a drill is inserted from the outlet-side passage 84 side at the same height as the first film 141, and the drill is kept at the same height as the first film 141 to one of the horizontal directions (here, to the right). Move. Then, the first to third films 143, 141, 142 are sequentially cut by the drill, and the through holes 153, 151, 152 are formed. In the example of FIG. 10, through-cutting is performed using a drill having substantially the same diameter as that of the outlet-side passage 84.

  Thereby, a cooling water passage 80 penetrating in the left-right direction is formed in the block body 11 of the cylinder block 10. In this case, the through-hole 151 extending in the left-right direction formed by cutting the first film 141 serves as a communication portion 86 that connects the inlet-side passage 83 and the deep bottom portion 13a of the water jacket 13. A circular through-hole 153 formed by cutting the third film 143 serves as a communication portion 85 that connects the inlet-side passage 83 and the outlet-side passage 84. In FIG. 10, the processing marks of the first to third films 141, 142, and 143 removed by the through-cutting hole processing are indicated by a one-dot chain line. In addition, you may insert a drill from the entrance side channel | path 83 side, and may perform a penetration cutting process.

  According to this embodiment, the first to third films 141, 142, and 143 are penetrated by only one processing, and the inlet side passage 83, the outlet side passage 84, and the deep bottom portion 13 a of the water jacket 13 are communicated. Can be made. That is, since the second and third films 142 and 143 are formed at both ends of the first film 141 in the left-right direction, when the first film 141 is cut, the second and third films 142 and 143 are formed. 143 is also cut, and all of the first to third films 141, 142, 143 can be penetrated by only one processing.

  In this case, since the through-hole 151 (communication portion 86) is formed from one end to the other end in the left-right direction of the first film 141, the opening area of the communication portion 86 is formed by cutting the third film 143. It becomes larger than the opening area of the through-hole 153 (communication part 85). Accordingly, communication portions to various devices provided outside the cylinder block that require a relatively small amount of cooling water while forming a large opening area of the communication portion 86 to the water jacket 13 that requires a relatively large amount of cooling water. The opening area of 85 can be formed small. Therefore, the two types of communication portions 85 and 86 corresponding to the required amount of cooling water can be formed by only one processing.

  Here, it is preferable to set the opening areas of the two types of communication portions 86 and 85 according to the amount of cooling water required for each of the water jacket 13 and various devices provided outside the cylinder block 10. More specifically, the diameter of the drill used for drilling and the third molding die 130 according to the amount of cooling water required for the water jacket 13 and various devices provided outside the cylinder block 10 are described. What is necessary is just to set the left-right width W1 (refer FIG. 7) of the lower part 131a of the part 131 on the engine front side. This point will be described.

  First, the opening area of the through hole 153 (communication portion 85) formed by cutting the third film 143 changes according to the diameter of the drill. Further, the opening area of the through-hole 151 (communication portion 86) formed from one end to the other end of the first film 141 in the horizontal direction is set to the diameter of the drill and the left-right width W1 of the third molding die 130. Will change accordingly. In this case, the diameter of the drill can be increased to the same diameter as the outlet side passage 84.

  Therefore, by adjusting the diameter of the drill and the left and right width W1 of the third molding die 130, the ratio of the opening areas of the communication portions 86 and 85 is adjusted. When the ratio of the opening areas of the communication portions 86 and 85 is adjusted, the ratio between the amount of cooling water circulated from the inlet side passage 83 to the water jacket 13 and the amount of cooling water circulated from the inlet side passage 83 to the outlet side passage 84. Is adjusted. That is, the ratio between the amount of cooling water supplied to the water jacket 13 and the amount of cooling water supplied to various devices provided outside the cylinder block 10 is adjusted. Therefore, in this embodiment, the diameter of the drill and the left and right widths of the third molding die 130 according to the amount of cooling water required for the water jacket 13 and various devices provided outside the cylinder block 10, respectively. W1 is set so that an appropriate flow rate distribution of the cooling water can be obtained.

  It is also possible to adjust the ratio of the opening areas of the communicating portions 86 and 85 only by setting the drill width in the left and right width W1 of the third molding die 130. In this case, it is possible to adjust the ratio of the opening areas of the communication portions 86 and 85 by setting the number of drilling operations together with the diameter of the drill, and by connecting the drilling operation multiple times, the communication portion It is possible to increase the degree of freedom in adjusting the ratio of the opening areas 86 and 85.

  INDUSTRIAL APPLICABILITY The present invention is applicable to a cylinder block of an internal combustion engine in which a timing chain housing space is integrally formed.

DESCRIPTION OF SYMBOLS 10 Cylinder block 11 Block main body 11a Wall part 12 Cylinder 13 Water jacket 13a Deep bottom part 30 Outer wall 31 Accommodating space 41 Timing chain 80 Cooling water passage 83 Inlet side passage (upstream side passage)
84 Exit side passage (downstream passage)
86 Communication portion 110 First molding die 120 Second molding die 130 Third molding die C1 First gap C2 Second gap C3 Third gap

Claims (12)

A cylinder block in which a water jacket is formed around the cylinder, and a storage space for the timing chain is integrally formed therein,
A cooling water passage is formed so as to penetrate the wall portion provided between the water jacket and the accommodation space,
The cooling water passage includes an upstream side passage through which cooling water from a water pump flows and communicates with the water jacket, and a downstream side passage through which cooling water flows out to the outside.
The cylinder block according to claim 1, wherein a cross-sectional area of the upstream side passage is larger than a cross-sectional area of the downstream side passage. In the cylinder block according to claim 1,
The cylinder block, wherein the cooling water passage is provided below a female screw hole to which a head bolt is tightened. In the cylinder block according to claim 1 or 2,
The cylinder block according to claim 1, wherein the cooling water passage is provided above a breathing hole provided to relieve pressure change in the crank chamber. In the cylinder block according to any one of claims 1 to 3,
The cylinder block, wherein the downstream passage is provided above a main gallery through which oil pumped by an oil pump is circulated. In the cylinder block according to any one of claims 1 to 4,
Cylinder characterized in that a portion of the water jacket on the side of the accommodation space is provided with a deep bottom portion formed deeper than other portions, and the deep bottom portion communicates with the cooling water passage. block. In the cylinder block according to claim 5,
The upstream side passage, the downstream side passage, and the water jacket are molded by separate molding dies,
A first molding die for molding the upstream passage is die-cut to one side in the horizontal direction, and a second molding die for shaping the downstream passage is die-cut to the other side in the horizontal direction; A cylinder block characterized in that the upstream side passage, the downstream side passage, and the water jacket are respectively formed by punching upward the third molding die for forming the water jacket. . In the cylinder block according to claim 6,
The first to third molding dies are assembled with a gap between them,
In this mold assembly state, the first molding die separates a first gap extending in the horizontal direction below the portion of the third molding die that molds the deep bottom portion, and On the one side in the horizontal direction of the portion forming the deep bottom portion, the second gap is arranged with a second gap continuous to one end in the horizontal direction of the first gap,
The second molding die is disposed horizontally on the other side in the horizontal direction of the portion for molding the deep bottom portion of the first molding die and the third molding die. A cylinder block, which is arranged with a third gap continuous to the other end in the direction. A method of manufacturing a cylinder block in which a water jacket is formed around a cylinder, and a storage space for a timing chain is integrally formed therein,
A cooling water passage is formed in the cylinder block so as to pass through a wall portion provided between the water jacket and the accommodation space.
A portion of the water jacket on the side of the accommodation space is provided with a deep bottom portion formed deeper than other portions,
The cooling water passage is provided with an upstream side passage through which cooling water from a water pump flows and communicates with the deep bottom portion of the water jacket, and a downstream side passage through which the cooling water flows out to the outside.
During the casting of the cylinder block, the upstream side passage, the downstream side passage, and the water jacket are molded by separate molding dies,
The first molding die that molds the upstream passage is die-cut in one of the horizontal directions, and the second molding die that molds the downstream passage is the mold of the first molding die. The third molding die for molding the water jacket is punched upward in a direction opposite to the punching direction, and the upstream passage, the downstream passage, and the water jacket are cut out upward. A method of manufacturing a cylinder block, wherein the cylinder block is formed on each cylinder block. In the manufacturing method of the cylinder block according to claim 8,
When casting the cylinder block, the first to third molding dies are assembled in a state where a gap is formed between them,
In this mold assembly state, the first molding die is separated from the lower side of the portion for molding the deep bottom portion of the third molding die with a first gap extending in the horizontal direction, and On one side in the horizontal direction of the portion forming the deep bottom portion, a second gap continuous with one end in the horizontal direction of the first gap is disposed,
The second molding die is placed horizontally on the other side in the horizontal direction of the portion of the first molding die and the third molding die where the deep bottom portion is molded. A cylinder block manufacturing method, wherein a third gap continuous to the other end of the direction is arranged with a gap therebetween. In the manufacturing method of the cylinder block according to claim 9,
After the cylinder block is cast, drilling is performed on the film formed at a position corresponding to the first gap so as to form a through hole from one end to the other end in the horizontal direction. Production method. In the manufacturing method of the cylinder block according to claim 10,
Forming the deep bottom portion of the diameter of the drill used for the drilling and the third molding die according to the amount of cooling water required for the water jacket and various devices provided outside the cylinder block. A method of manufacturing a cylinder block, wherein a horizontal width of a portion to be set is set. In the manufacturing method of the cylinder block according to claim 10,
The diameter of the drill used for the drilling and the number of drilling operations are set according to the amount of cooling water required for the water jacket and various devices provided outside the cylinder block. Production method.

Images