JP2016164376A - Cylinder block, internal combustion engine equipped with the same and method of manufacturing cylinder block - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology for easily and effectively implementing improvement of the quality, strength and coolability of a cylinder block.SOLUTION: Connection wall parts 64, 65 for connecting a cylinder bore wall part 66 having a cylinder bore 66a and side wall parts 62c, 62d are formed in a block water jacket BWJ. When cast-molding a cylinder block 6, the connection wall parts 64, 65 are molded over the whole area in the depth direction of the block water jacket BWJ. After cast-molding the cylinder block 6, by linearly scraping off upper portions of the connection wall parts 64, 65 with use of an end mill EM having a diameter that is almost the same with the width dimension of the block water jacket BWJ, flat portions 30 are formed on the block water jacket BWJ. The flat portion 30 is formed such that a central angle having the vertex of the angle in the center of the cylinder bore 66a is within a range of 25° to 35°, preferably 30°.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a cylinder block configured such that a cylinder head is fastened to a deck surface, an internal combustion engine including the same, and a method of manufacturing the cylinder block.

  Japanese Patent Laying-Open No. 2003-65146 (Patent Document 1) describes an internal combustion engine including a water jacket portion configured to surround a cylinder bore wall portion. The water jacket portion is formed with a plurality of rib walls that divide the water jacket portion into a plurality of spaces in the circumferential direction.

  The rib wall is formed integrally with the water jacket portion when the cylinder block is cast. The rib wall is molded so as to extend over the entire length in the depth direction of the water jacket portion, and then a through hole is formed at the bottom of the rib wall by the end mill. The through hole communicates the partitioned spaces in the water jacket portion.

  In the cylinder block, the rigidity of the radial direction of the cylinder bore wall portion is improved by the rib wall connecting the cylinder bore wall portion and the outer wall portion, and the cooling water is circulated and flowed throughout the water jacket portion through the through hole. This improves the cooling performance.

  Further, since the rib wall is formed over the entire length in the depth direction of the water jacket portion, when the cylinder block is cast and molded, the rib wall functions as a runner through which the molten metal flows, and the cylinder bore wall portion The molten metal can be satisfactorily filled up to the cylinder head fastening side end. As a result, the formation of a cast hole at the cylinder head fastening side end of the cylinder bore wall is prevented, and the sealing performance and the heat dissipation of the cylinder bore wall are improved.

JP 2003-65146 A

  However, in the cylinder block described in the above publication, although the rigidity can be improved by the rib wall, since the cooling water circulates and flows in the bottom of the water jacket portion, the cylinder block requires the most cooling. The cylinder head fastening side cannot be cooled effectively.

  After molding the rib wall over the entire length in the depth direction of the water jacket part, it is conceivable to cut off a part of the through hole on the cylinder head fastening side of the rib wall by machining, but the cooling water flowing through the water jacket part It is necessary to process so as not to increase the resistance.

  The present invention has been made in view of the above, and an object of the present invention is to provide a technique that can easily and effectively realize improvement in quality, strength and cooling performance of a cylinder block.

  The internal combustion engine of the present invention employs the following means in order to achieve the above-described object.

  According to the preferable form of the cylinder block according to the present invention, the cylinder block is configured such that the cylinder head is fastened to the deck surface. The cylinder block includes an outer wall portion constituting an outer shell, a cylinder bore wall portion constituting a cylinder bore, a water jacket portion configured to surround the cylinder bore wall portion, and the water jacket portion partitioned into a plurality of spaces. And a partition wall portion connected to the outer wall portion and the cylinder bore wall portion. The water jacket portion is configured with a predetermined width between the outer wall portion and the cylinder bore wall portion, and is configured such that the deck surface side is open. The partition wall portion is molded so as to extend from the bottom portion of the water jacket portion toward the deck surface side. Moreover, the water jacket part has a flat part constituted by scraping off the deck surface side of the partition part wall by machining. The flat portion is configured to have a width and a predetermined depth substantially the same as the predetermined width, and a central angle formed by both ends of the flat portion and the center of the cylinder bore is 25 ° to 35 °. It is configured to be within the range of °. Here, the “both ends of the flat portion” in the present invention corresponds to two end portions that intersect a direction orthogonal to both the width direction and the depth direction of the flat portion.

  According to the present invention, when the cylinder block is cast and molded, since the partition wall portion is molded so as to extend from the deck surface to the bottom of the water jacket portion, the partition wall portion of the cylinder bore wall portion is formed. It can be used as a runner that allows molten metal to flow at the end of the deck surface. Thereby, the molten metal can be satisfactorily filled up to the deck surface side end of the cylinder bore wall, and it is possible to satisfactorily prevent the formation of a cast hole at the deck surface side end of the cylinder bore wall. As a result, the quality of the cylinder block can be improved, and the sealing performance and the heat dissipation of the cylinder bore wall can be improved. The partition wall portion can also improve the strength of the cylinder bore wall portion.

  After casting the cylinder block, the deck wall side of the partition wall is machined to ensure the flow of cooling water on the deck surface side of the cylinder bore wall. It is possible to improve the cooling performance on the deck surface side of the cylinder bore wall portion, which is a portion that requires. In addition, since it only performs a machining, the structure which can improve the said cooling property can be ensured easily.

  Moreover, the flat portion formed by machining has the same width as the width of the water jacket portion, and the central angle with the center of the cylinder bore as the vertex of the angle is in the range of 25 ° to 35 °. Therefore, there is no level difference that becomes resistance of the cooling water flowing through the water jacket portion, and the cooling performance is not lowered.

  According to the further form of the cylinder block which concerns on this invention, the partition wall part is comprised so that the hot_water | molten_metal flow direction at the time of casting molding a cylinder block may be followed. The term “along the molten metal flow direction” in the present invention is not limited to the aspect along the main flow direction of the molten metal flowing into the mold cavity from the gate, but also along the tributary direction that separates from the main flow and flows toward each part of the mold cavity. Embodiments are suitably included.

  According to this embodiment, when casting the cylinder block, the molten metal easily flows into the mold cavity that forms the partition wall portion of the casting mold. As a result, the molten metal can be more satisfactorily filled to the deck surface side end of the cylinder bore wall, and it is possible to satisfactorily prevent the formation of a cast hole at the deck surface side end of the cylinder bore wall. As a result, the quality of the cylinder block can be improved, and the sealing performance and the heat dissipation of the cylinder bore wall can be improved.

  According to the further form of the cylinder block which concerns on this invention of the aspect comprised so that a partition wall part may follow a hot water flow direction, a partition wall part is a 1st partition wall on both sides of a 1st partition wall part and a cylinder bore And a second partition wall portion disposed at a position facing the portion.

  According to this embodiment, when the cylinder block is cast, the molten metal that has flowed from one of the mold cavities constituting the first and second partition walls into the mold cavities constituting the cylinder bore walls is And since it can be made to flow out from the other mold cavity part which constitutes the 2nd partition wall part, the inflow of the molten metal to the mold cavity part which constitutes the cylinder bore wall part can be made still better.

  According to the further form of the cylinder block which concerns on this invention, the flat part comprised by scraping off the deck surface side of a partition part wall by machining is 20% thru | or 50% of the full length of a cylinder bore. It is comprised so that it may become.

  According to this embodiment, it is possible to effectively cool the cylinder bore wall portion corresponding to the portion in which the piston slides in the cylinder bore, and to suppress the cooling of the portion other than the portion to prevent heat loss.

  According to the further form of the cylinder block which concerns on this invention, a partition wall part is arrange | positioned at the upstream side wall surface arrange | positioned in the flow direction upstream of the cooling water which flows in the water jacket part, and the flow direction downstream of a cooling water. And a downstream side wall surface. And a downstream side wall surface is comprised so that it may have an inclination which goes away from an upstream side wall surface as it goes to the bottom part of a water jacket part.

  According to this embodiment, the mold can be easily removed when the mold is opened after casting the cylinder block. In addition, by adopting a configuration in which only the downstream side wall surface is provided with an inclination, the flow of cooling water is suppressed on the upstream side wall surface side of the bottom portion of the water jacket portion while ensuring the die-cutting property, and the excess of the bottom portion is suppressed. Cooling can be suppressed.

  According to the preferable form of the internal combustion engine which concerns on this invention, The cylinder block which concerns on this invention of one of the aspects mentioned above, The cylinder head fastened to the said cylinder block, The water pump attached to a cylinder block is provided. ing. The internal combustion engine is configured to cool the cylinder block and the cylinder head with cooling water supplied from a water pump.

  According to the present invention, since it has a configuration including the cylinder block according to the present invention of any one of the aspects described above, the same effect as the effect exerted by the cylinder block of the present invention, for example, the quality of the cylinder block can be improved. The effect which can be improved, the effect which can improve sealing performance and the heat dissipation of a cylinder bore wall part, the effect which can improve the intensity | strength of a cylinder block, the effect which can improve cooling property, etc. can be show | played.

  According to the preferable form of the manufacturing method of the cylinder block which concerns on this invention, the manufacturing method of the cylinder block comprised so that a cylinder head may be fastened by the deck surface is comprised. In the method of manufacturing the cylinder block, the cylinder block is cast and molded so as to include an outer wall portion, a cylinder bore wall portion, a water jacket portion, and a partition wall portion extending from the deck surface to the bottom of the water jacket portion, After casting the cylinder block, machining is performed on the deck surface side of the partition wall portion to form a flat portion having a width and a predetermined depth substantially equal to the predetermined width in the water jacket portion.

  The outer wall portion constitutes an outer shell, and the cylinder bore wall portion constitutes a cylinder bore. Further, the water jacket portion is configured to surround the cylinder bore wall portion with a predetermined width and to open the deck surface side. Further, the partition wall portion is connected to the outer wall portion and the cylinder bore wall portion so as to partition the inside of the water jacket portion into a plurality of spaces. The flat portion is formed such that a central angle formed by both ends of the flat portion and the center of the cylinder bore is within a range of 25 ° to 35 °. Here, the “both end portions of the flat portion” in the present invention corresponds to two end portions that intersect the direction orthogonal to both the width direction and the depth direction of the flat portion.

  According to the present invention, when the cylinder block is cast and molded, the partition wall portion is molded so as to extend from the deck surface to the bottom of the water jacket portion, so that the partition wall portion is formed on the deck surface side of the cylinder bore wall portion. It can be used as a runner through which molten metal flows to the end. Thereby, the molten metal can be satisfactorily filled up to the deck surface side end of the cylinder bore wall, and it is possible to satisfactorily prevent the formation of a cast hole at the deck surface side end of the cylinder bore wall. As a result, the quality of the cylinder block can be improved, and the sealing performance and the heat dissipation of the cylinder bore wall can be improved. The partition wall portion can also improve the strength of the cylinder bore wall portion.

  And after casting a cylinder block, since the machining is performed on the deck surface side of the partition wall portion, the flow of cooling water on the deck surface side of the cylinder bore wall portion can be ensured. Thereby, it is possible to improve the cooling performance on the deck surface side of the cylinder bore wall, which is the portion that needs the most cooling out of the cylinder bore wall. In addition, since it only performs a machining, the structure which can improve the said cooling property can be ensured easily.

  In addition, the flat portion formed by machining has the same width as the width of the water jacket portion, and the center angle of the cylinder bore is configured within a range of 25 ° to 35 °, and thus flows through the water jacket portion. There is no level difference that becomes the resistance of the cooling water, and the cooling performance is not lowered.

  ADVANTAGE OF THE INVENTION According to this invention, the technique which can implement | achieve the improvement of the intensity | strength and cooling property of a cylinder bore wall part easily can be provided.

1 is a schematic configuration diagram showing an outline of a configuration of an internal combustion engine 1 according to an embodiment of the present invention. 2 is a side view of a cylinder head 2. FIG. 2 is a cross-sectional view schematically showing the configuration of a cylinder head 2. FIG. 2 is a perspective view showing an outline of a configuration of a cylinder block 6. FIG. It is the top view which looked at the cylinder block from the upper surface. It is a side view of a cylinder block. FIG. 3 is an enlarged plan view showing a flat portion 30 in an enlarged manner. It is sectional drawing which shows the AA cross section of FIG. It is sectional drawing which shows the BB cross section of FIG. It is a perspective view which shows the cylinder block 6 after casting molding. It is the top view which looked at the cylinder block 6 after casting molding from the upper surface. It is explanatory drawing which shows a mode that the cylinder block 6 is cast-molded. It is explanatory drawing which shows a mode that machining is carried out to the upper end surface part of the connection wall part 64,65. It is sectional drawing which shows the DD cross section of FIG. It is a perspective view which shows the cylinder block 6 of a modification. It is explanatory drawing which shows a mode that the cylinder block 6 is cast-molded by changing a hot water flow direction. It is a perspective view which shows the cylinder block 6 which cast-molded by changing the hot water flow direction. It is sectional drawing which shows the cross section of the cylinder block 6 of a modification.

  Next, the best mode for carrying out the present invention will be described using examples.

  As shown in FIG. 1, an internal combustion engine 1 according to an embodiment of the present invention includes a cylinder head 2, a rocker cover 4 attached to the upper part of the cylinder head 2, and the invention attached to the lower part of the cylinder head 2. The cylinder block 6 according to the embodiment, the upper oil pan 8 attached to the lower portion of the cylinder block 6, the lower oil pan 10 attached to the lower portion of the upper oil pan 8, and the intake connected to the cylinder head 2 A manifold 12 and a water pump 16 attached to the cylinder block 6 are provided.

  The internal combustion engine 1 is configured as an in-line three-cylinder engine in which three cylinders are arranged in series. A piston (not shown) is reciprocated by a combustion pressure generated in a combustion chamber described later, and the reciprocating motion of the piston is not shown. Power is output by converting it into rotational movement of the shaft. In this embodiment, for the sake of convenience, the rocker cover 4 side, that is, the upper side of the paper in FIG. 1 is defined as “upper” or “upper side”, and the lower oil pan 10 side, that is, the lower side of the paper in FIG. Is defined as “downward” or “downward”.

  As shown in FIG. 2, the cylinder head 2 includes a front wall portion 26a, a rear wall portion 26b, a side wall portion 26c connecting the front wall portion 26a and the rear wall portion 26b, an upper deck portion 22, and a lower deck portion 24. And. An attachment portion 28 for attaching the intake manifold 12 is formed on the side wall portion 26c.

  The upper deck portion 22 and the lower deck portion 24 are connected to the front wall portion 26a, the rear wall portion 26b, and the side wall portion 26c. A head water jacket HWJ is formed between the upper deck portion 22 and the lower deck portion 24 as shown in FIG. Further, the lower deck portion 24 is formed with a combustion chamber constituting concave portion 25 that constitutes a part of the combustion chamber.

  As shown in FIG. 3, the three combustion chamber constituting recesses 25 are arranged in series. The combustion chamber is formed by the combustion chamber constituting recess 25, a cylinder bore 66a (described later) formed in the cylinder block 6, and an upper surface of a piston (not shown) accommodated in the cylinder bore 66a.

  The head water jacket HWJ is configured as a cooling water passage through which cooling water flows, and communicates with a block water jacket BWJ of the cylinder block 6 described later when the cylinder head 2 is fastened to the cylinder block 6. The cylinder head 2, in particular, the periphery of the combustion chamber constituting recess 25 is cooled by the coolant flowing through the head water jacket HWJ.

  As shown in FIGS. 4 and 5, the cylinder block 6 includes a front wall portion 62a, a rear wall portion 62b, two side wall portions 62c and 62d connected to the front wall portion 62a and the rear wall portion 62b, and a cylinder bore. A cylinder bore wall portion 66 having 66a, and a plurality of connecting wall portions 64, 65 for connecting the side wall portions 62c, 62d and the cylinder bore wall portion 66 are provided.

  The upper end surfaces of the front wall portion 62a, the rear wall portion 62b, the side wall portions 62c and 62d, and the cylinder bore wall portion 66 are formed to be flush with each other, and are configured as a top deck surface 60 with which the lower deck portion 24 of the cylinder head 2 abuts. Has been. The front wall portion 62a, the rear wall portion 62b, and the side wall portions 62c and 62d correspond to the “outer wall portion” in the present invention, and the top deck surface 60 is an example of an implementation configuration corresponding to the “deck surface” in the present invention. .

  As shown in FIG. 6, the side wall part 62 c is provided with a water pump housing part 72 for attaching the water pump 16 and a suction passage part 74 for guiding cooling water to the water pump housing part 72.

  As shown in FIGS. 4 and 5, a block water jacket BWJ is formed between the front wall portion 62 a, the rear wall portion 62 b, the side wall portions 62 c and 62 d, and the cylinder bore wall portion 66.

  As shown in FIGS. 4 and 5, the cylinder bore wall 66 is connected to each other so that three cylinder bores 66a are arranged in series to form a Siamese cylinder. A piston (not shown) slides in the cylinder bore 66a.

  The block water jacket BWJ is configured as a cooling water passage through which cooling water flows. The cooling water flowing through the block water jacket BWJ cools the cylinder block 6, particularly the periphery of the cylinder bore wall 66. The block water jacket BWJ is open at the top deck surface 60. In the present embodiment, the depth Lj of the block water jacket BWJ is configured to be 70% to 90% of the total length Lb of the cylinder bore 66a.

  The block water jacket BWJ is configured concentrically with each cylinder bore wall 66 so as to surround each cylinder bore wall 66 with a predetermined width. The block water jacket BWJ is an example of an implementation configuration corresponding to the “water jacket portion” in the present invention.

  The block water jacket BWJ is basically constituted by an arcuate surface, but the portion of the block water jacket BWJ in which the connecting wall portions 64 and 65 are provided is a flat surface 32 as shown in FIG. It is comprised by. Hereinafter, the portion constituted by the flat surface 32 in the block water jacket BWJ is referred to as a flat portion 30.

  As shown in FIG. 7, the flat part 30 has a central angle with the center of the cylinder bore 66a as the apex of the corner (both ends of the flat part 30 intersecting the circumferential direction of the block water jacket BWJ, and the cylinder bore 66a). The center angle formed by the center of the center of the head is 25 ° to 35 °, preferably 30 °.

  As shown in FIGS. 4 and 5, the connecting wall portion 64 and the connecting wall portion 65 include a right jacket portion BWJR that extends in the arrangement direction of the cylinder bores 66a with the cylinder bore wall portion 66 of the block water jacket BWJ, and a left side. It is provided in each of the jacket portions BWJL. The connecting wall portions 64 and 65 are disposed so as to face each other, and are configured to connect each cylinder bore wall portion 66, the side wall portion 62c, and the side wall portion 62d in a direction orthogonal to the arrangement direction of the cylinder bores 66a. Yes.

  The connecting wall portions 64 and 65 are configured to partition the block water jacket BWJ into a plurality of chambers in the arrangement direction of the cylinder bores 66a. The connection wall parts 64 and 65 are an example of the implementation structure corresponding to the "partition wall part" in this invention. Moreover, the connection wall parts 64 and 65 are examples of the implementation structure corresponding to the "1st partition wall part" and the "2nd partition wall part" in this invention.

  Further, as shown in FIGS. 8 and 9, the connecting wall portions 64 and 65 are not provided over the entire depth direction of the block water jacket BWJ, and the bottom of the block water jacket BWJ extends from the bottom of the cylinder bore 66a. It is configured to have a height corresponding to 20% to 70% of the total length Lb.

  In other words, the connecting wall portions 64 and 65 are machined to a depth corresponding to 20% to 50% of the total length Lb of the cylinder bore 66a. Thereby, the communication of the block water jacket BWJ in the arrangement direction of the cylinder bores 66a is ensured.

  Further, the wall surface 64b of the connecting wall portion 64 that faces the rear wall portion 62b of the cylinder block 6 is, as shown in FIG. 9, the front wall of the cylinder block 6 in the connecting wall portion 64 as it goes toward the bottom of the block water jacket BWJ. It is comprised so that it may incline away from the wall surface 64a which faces the wall part 62a. The wall surface 64a is configured to be substantially along the vertical direction.

  Furthermore, although illustration is omitted, the connecting wall portion 65 has the same configuration as the connecting wall portion 64. That is, the wall surface 65b of the connecting wall portion 65 facing the rear wall portion 62b of the cylinder block 6 is directed toward the bottom of the block water jacket BWJ, and the wall surface 65a of the connecting wall portion 65 faces the front wall portion 62a of the cylinder block 6. The wall surface 65a is configured to be substantially along the vertical direction. The wall surfaces 64a and 65a correspond to the “upstream sidewall surface” in the present invention, and the wall surfaces 64b and 65b are an example of an implementation configuration corresponding to the “downstream sidewall surface” in the present invention.

  Next, the manufacturing method of the cylinder block 6 comprised in this way is demonstrated. First, as shown in FIG. 10 and FIG. 11, the mold is clamped and the molten metal is poured into the front wall portion 62a, the rear wall portion 62b, the side wall portions 62c and 62d, the cylinder bore wall portion 66, and a plurality of them. The connecting wall portions 64 and 65 and the cylinder block provided are cast.

  As shown in FIG. 12, the mold is provided with a gate INP in a lower part of the surface on the side where the side wall 62c is molded, and a gas in an upper part of the surface on the side where the side wall 62d is molded. An outlet GOUT is provided so that the molten metal flows from the lower left side to the upper right side in FIG. 12 (thick arrow in FIG. 12).

  Here, in the casting molding step of the cylinder block, the connecting wall portions 64 and 65 are molded to reach the top deck surface 60 of the cylinder block 6 from the bottom over the entire depth direction of the block water jacket BWJ. (See FIGS. 10 and 11).

  In this way, the connecting wall portions 64 and 65 are formed to have a length that reaches the top deck surface 60 of the cylinder block 6 from the bottom of the block water jacket BWJ, thereby forming the connecting wall portions 64 and 65. Since the cavity for the connecting wall of the mold can be used as a runner for pouring the molten metal into the cavity for the bore of the mold for molding the cylinder bore wall 66, the cavity for the bore wall The molten metal can be satisfactorily filled in the entire longitudinal direction (the axial direction of the cylinder bore 66a and the vertical direction in FIG. 12).

  Further, as shown by the thick arrows in FIG. 12, since the connecting wall portions 64 and 65 are provided along the main flow direction of the molten metal, the connecting wall portion of the mold for molding the connecting wall portions 64 and 65 is used. The inflow property of the molten metal into the hollow portion can be improved. In the present embodiment, “the main flow direction of the molten metal” typically means the direction in which the molten metal is directed from the molten metal inlet INP side (side wall part 62c side) to the side wall part 62d, for example, the arrangement direction of the cylinder bores 66a. And the direction in which the molten metal moves upward in the axial direction of the cylinder bore 66a. Further, since the connecting wall portions 64 and 65 are provided so as to face each other across the cylinder bore wall portion 66, the cavity for the bore wall portion is changed from the connecting wall portion cavity portion of the mold for molding the connecting wall portion 64. The molten metal that has flowed into the portion can flow out to the side wall portion cavity portion for molding the side wall portion 62d through the connecting wall portion cavity portion of the mold for forming the connecting wall portion 65. Thereby, the flow of the molten metal into the bore wall cavity can be further improved.

  As a result, the molten metal is satisfactorily filled up to the top deck surface 60 side of the cylinder bore wall 66, and it is possible to satisfactorily prevent the occurrence of a cast hole on the top deck surface 60 side of the cylinder bore wall 66. Therefore, the quality of the cylinder block 6 is improved, and the sealing performance and the heat dissipation of the cylinder bore wall 66 are improved. The connecting wall portions 64 and 65 also improve the strength of the cylinder bore wall portion 66.

  Further, the inclination provided on the wall surfaces 64b and 65b of the connecting wall portions 64 and 65 functions as a casting inclination for removing a mold for molding the water jacket BWJ for the block when the mold is opened. Improves. The direction in which the mold for molding the block water jacket BWJ is pulled out is the upward direction in FIG.

  Then, after the cylinder block 6 is cast and molded, as shown in FIGS. 7 and 13, machining is performed to scrape the upper portions of the connecting wall portions 64 and 65 with an end mill EM or the like. The machining is performed using an end mill EM having a diameter substantially the same as the width dimension of the block water jacket BWJ.

  Specifically, as shown in FIG. 13, the end mill EM is lowered from the upper side of the connecting wall portions 64 and 65 and brought into contact with the connecting wall portions 64 and 65, and the end mill EM is moved a predetermined distance from the contacted state. The upper portions of the connecting wall portions 64 and 65 are scraped off by being lowered vertically. In the present embodiment, the end mill EM is moved in the vertically downward direction within a range of 20% to 50% of the total length Lb of the cylinder bore 66a.

  Then, the end mill EM is linearly moved by a predetermined distance in the arrangement direction of the cylinder bores 66 while the end mill EM is lowered vertically by a predetermined distance, and then the end mill EM is lifted vertically upward by Machining is complete.

  As a result of such machining, a flat portion 30 made of a flat surface 32 is formed in the block water jacket BWJ where the connecting wall portions 64 and 65 are provided, as shown in FIG. In this embodiment, the linear movement of the cylinder bores 66a in the arrangement direction by the end mill EM is a center angle (the center of the cylinder bore 66a is the apex of the corners of the block water jacket BWJ among the ends of the flat portion 30). The central angle formed by both ends intersecting the circumferential direction and the center of the cylinder bore 66a) is within a range of 25 ° to 35 °, preferably 30 °.

  That is, the center of the end mill EM at the processing start position of the connection wall portions 64 and 65 by the end mill EM, the center of the cylinder bore 66a, and the center of the end mill EM at the processing end position of the connection wall portions 64 and 65 by the end mill EM are connected. Is within a range of 25 ° to 35 °, preferably 30 °.

  Thus, the flat portion having the same width as the block water jacket BWJ and the depth of 20% to 50% of the total length Lb of the cylinder bore 66a in the block water jacket BWJ provided with the connecting wall portions 64 and 65. The cylinder block 6 provided with 30 is manufactured.

  Next, the flow of the cooling water discharged by the water pump 16 driven in accordance with the operation of the internal combustion engine 1 configured as described above and supplied to the block water jacket BWJ will be described. The cooling water discharged by the water pump 16 is introduced into the block water jacket BWJ from the side wall 62c side of the block water jacket BWJ that surrounds the cylinder bore wall 66 closest to the front wall 62a, and is the most rear wall 62b. It flows through both side portions BWJL and BWJR of the block water jacket BWJ toward the block water jacket BWJ that surrounds the cylinder bore wall 66 closer to the block.

  Here, in the lower portion of the block water jacket BWJ, as shown by the thick broken line arrows in FIG. 14, the flow of the cooling water is inhibited by the connecting wall portions 64 and 65, so that the supercooling by the cooling water is suppressed. The On the other hand, in the upper part of the block water jacket BWJ, as shown by the thick solid arrows in FIG. An effect can be obtained.

  The flat portion 30 is formed to have substantially the same width as that of the block water jacket BWJ by using an end mill EM having a diameter substantially the same as the width dimension of the block water jacket BWJ, and the center of the cylinder bore 66a is set to the corner apex. The central angle (the central angle formed by the ends of the flat portion 30 intersecting the circumferential direction of the block water jacket BWJ and the center of the cylinder bore 66a) is 25 ° to 35 °, preferably 30 °. Therefore, there is no level difference that becomes the resistance of the cooling water flowing through the block water jacket BWJ in a plan view. As a result, the cooling performance is not lowered.

  Further, since the flat portion 30 is formed to a depth of 20% to 50% of the entire length Lb of the cylinder bore 66a, the cylinder bore wall portion 66 corresponding to the portion where the piston slides in the cylinder bore 66a is effectively formed. While cooling, cooling other than that part can be suppressed to prevent heat loss.

  In the present embodiment, the connecting wall portion 64 and the connecting wall portion 65 are provided at positions facing each other across the cylinder bore wall portion 66, but the connecting wall portion 64 and the connecting wall portion 65 may not be facing each other. good.

  In the present embodiment, the main flow direction of the molten metal (the direction from the molten metal inlet INP side (side wall portion 62c side) toward the side wall portion 62d, for example, the direction intersecting the arrangement direction of the cylinder bores 66a and the axial direction of the cylinder bores 66a However, the present invention is not limited to this. For example, the connection wall portions 64 and 65 may be arranged along the branch direction of the molten metal (the direction in which the molten metal is separated from the main flow and flows toward each part of the mold cavity, for example, the arrangement direction of the cylinder bores 66a).

  In the present embodiment, the connecting wall portion 64 and the connecting wall portion 65 are provided only in the direction orthogonal to the arrangement direction of the cylinder bores 66a. However, the present invention is not limited to this. For example, as shown in FIG. 15, it is good also as a structure which provides the connection wall part 64 and the connection wall part 65 also in the sequence direction of the cylinder bore 66a.

  In the present embodiment, the mold is provided with a gate INP at a lower part of the surface on the side where the side wall 62c is molded, and a gas vent GOUT at an upper part of the surface on the side where the side wall 62d is molded. Although it was set as the structure installed, it is not restricted to this. For example, as shown in FIG. 16, the mold is provided with a spout INP at a lower portion of the surface on the side where the rear wall portion 62b is molded, and at an upper portion of the surface on the side where the front wall portion 62a is molded. The gas vent GOUT may be installed.

  In this case, the connection wall portions 64 and 65 are preferably installed in the arrangement direction of the cylinder bores 66a so as to be along the main flow direction of the molten metal flow. Specifically, as shown in FIG. 17, the connecting wall portion 64 is provided so as to connect the rear wall portion 62b and the cylinder bore wall portion 66 disposed closest to the rear wall portion 62b among the cylinder bore wall portions 66. At the same time, the connecting wall 65 may be configured to connect the front wall 62a and the cylinder bore wall 66 disposed closest to the front wall 62a among the cylinder bore walls 66.

  In the present embodiment, the wall surfaces 64b and 65b facing the rear wall portion 62b of the cylinder block 6 in the connecting wall portions 64 and 65 are inclined, but the present invention is not limited to this. For example, the wall surfaces 64b and 65b may be configured not to be inclined. Further, as shown in FIG. 18, in addition to the wall surfaces 64b and 65b, the wall surfaces 64a and 65a facing the front wall portion 62a of the cylinder block 6 among the connecting wall portions 64 and 65 may be inclined.

  This embodiment shows an example for carrying out the present invention. Therefore, the present invention is not limited to the configuration of the present embodiment.

1 Internal combustion engine (internal combustion engine)
2 Cylinder head (cylinder head)
4 Rocker cover 6 Cylinder block (cylinder block)
8 Upper oil pan 10 Lower oil pan 12 Intake manifold 16 Water pump (water pump)
22 Upper deck portion 24 Lower deck portion 25 Combustion chamber constituting concave portion 26a Front wall portion 26b Rear wall portion 26c Side wall portion 28 Mounting portion 30 Flat portion (flat portion)
32 Flat surface 62a Front wall (outer wall)
62b Rear wall (outer wall)
62c Side wall (outer wall)
62d Side wall (outer wall)
64 connecting wall part (partition wall part, first partition wall part, second partition wall part)
64a Wall surface (upstream side wall surface)
64b Wall surface (downstream side wall surface)
65 connecting wall (partition wall, second partition, first partition wall)
65a Wall surface (upstream side wall surface)
65b Wall surface (downstream side wall surface)
66 Cylinder bore wall (cylinder bore wall)
66a Cylinder bore (cylinder bore)
72 Water pump housing part 74 Suction passage part Water jacket for HWJ head Water jacket for BWJ block (Water jacket part)
BWJL Left jacket part BWJR Right jacket part INP Spout GOUT Gas vent EM End mill Lb Overall length of cylinder bore Lj Depth of water jacket for block

Claims (7)

A cylinder block configured such that a cylinder head is fastened to a deck surface,
An outer wall constituting the outer shell;
A cylinder bore wall constituting the cylinder bore;
A water jacket portion configured to have a predetermined width between the outer wall portion and the cylinder bore wall portion so as to surround the cylinder bore wall portion, and configured to open the deck surface side,
A partition wall portion that is connected to the outer wall portion and the cylinder bore wall portion so as to partition the inside of the water jacket portion into a plurality of spaces, and that is molded so as to extend from the bottom portion of the water jacket portion toward the deck surface side. When,
With
The water jacket portion has a flat portion configured by scraping the deck surface side of the partition wall portion by machining,
The flat portion is configured to have a width and a predetermined depth substantially the same as the predetermined width, and a central angle formed by both ends of the flat portion and the center of the cylinder bore is 25 ° to 35 °. Cylinder block configured to be within the range of °. The cylinder block according to claim 1, wherein the partition wall portion is configured to be along a hot water flow direction when the cylinder block is cast and formed. The partition wall portion is configured to include a first partition wall portion and a second partition wall portion disposed at a position facing the first partition wall portion with the cylinder bore interposed therebetween. Cylinder block as described.   The cylinder block according to any one of claims 1 to 3, wherein the flat portion is configured such that the predetermined depth is 20% to 50% of a total length of the cylinder bore. The partition wall portion has an upstream side wall surface disposed on the upstream side in the flow direction of the cooling water flowing in the water jacket portion, and a downstream side wall surface disposed on the downstream side in the flow direction of the cooling water. ,
The cylinder block according to any one of claims 1 to 4, wherein the downstream side wall surface is configured to be inclined so as to move away from the upstream side wall surface toward the bottom of the water jacket portion. Cylinder block according to any one of claims 1 to 5,
A cylinder head fastened to the cylinder block;
A water pump attached to the cylinder block;
With
An internal combustion engine configured to cool the cylinder block and the cylinder head with cooling water supplied from the water pump. A cylinder block manufacturing method configured to fasten a cylinder head to a deck surface,
An outer wall portion constituting an outer shell, a cylinder bore wall portion constituting a cylinder bore, a water jacket portion surrounding the cylinder bore wall portion with a predetermined width and opening on the deck surface side, and partitioning the water jacket portion into a plurality of spaces The cylinder block is cast so as to include a partition wall portion connected to the outer wall portion and the cylinder bore wall portion and extending from the deck surface to a bottom portion of the water jacket portion,
After casting the cylinder block, machining is performed on the deck surface side of the partition wall portion to form a flat portion having a width and a predetermined depth substantially equal to the predetermined width in the water jacket portion. And
A method of manufacturing a cylinder block, wherein the flat portion is formed so that a central angle formed by both ends of the flat portion and the center of the cylinder bore is within a range of 25 ° to 35 °.

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