JP5281345B2 - Closed deck type cylinder block - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylinder block of closed deck type capable of preventing deformation of cylinder bore when the cylinder block is fastened with a cylinder head, as well as capable of effectively cooling an upper part of the cylinder bore. <P>SOLUTION: A cylinder block 10 of closed deck type includes a plurality of cylinders 12 in which a piston slides, and a water jacket 16 for circulating cooling water for cooling the cylinder 12. Head bolt holes 15 are formed, outside the water jacket 16. In the cylinder block 10, a hollow member 30 for cooling is arranged around the cylinder 12 and envelope casted. The hollow member 30 includes an inner cylinder portion 30a and an outer cylinder portion 30b, where a plurality of interconnecting members 45 for interconnecting an inner wall surface of the inner cylinder portion 30a and an inner wall surface of the outer cylinder portion 30b are provided in distributed manner. The interconnecting members 45 is arranged at a position avoiding a straight line connecting a center X of the head bolt hole 15 and a bore center O of the cylinder 12. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a closed deck type cylinder block in which a water jacket is formed by casting an insert member.

  A cylinder block used in a water-cooled engine has a water jacket for engine cooling. The water jacket is formed between the cylinder and the outer wall of the block, and cooling water flows through the water jacket. By flowing the cooling water through the water jacket, the effect of cooling the cylinder can be obtained, and the noise generated in the cylinder bore can be absorbed to reduce the noise.

  Here, the cylinder block is roughly classified into two types, a closed deck type and an open deck type. The closed deck type includes a bridge connecting a cylinder having a cylinder bore and a block outer wall on the upper deck surface on the cylinder head fastening side. On the other hand, the open deck type does not have a bridge and the cylinder and the block outer wall are separated on the upper deck surface. The closed deck type cylinder has a merit such that the cylinder and the block outer wall are joined by providing a bridge on the upper deck surface of the cylinder block, which improves vibration resistance and reduces noise. Has the disadvantage of becoming difficult.

  In recent years, cylinder blocks are often manufactured by die casting from the viewpoint of production efficiency. However, in order to form a water jacket provided in a closed deck type cylinder block, it is necessary to use a collapsible core, and the advantages of die casting cannot be utilized. That is, at the time of die-casting the cylinder block, it is necessary to supply the molten metal with a casting pressure that does not break the core that forms the water jacket, and it is necessary to slow the molten metal flow rate. For this reason, the production speed is reduced, and it becomes difficult to obtain the mass production effect that is considered to be a merit in die casting.

  For these reasons, it is not uncommon for the closed deck type cylinder block to be molded by casting. Also, there is a case where rigidity is secured by reinforcing another part of the cylinder block and an open deck type cylinder block is adopted for the engine. However, when a higher rigidity is desired (for example, when used for a diesel engine), a closed deck type cylinder block is more advantageous. Therefore, improvement in production efficiency is also required for a closed deck type cylinder block.

Regarding a closed deck type cylinder block, for example, Patent Document 1 discloses a technique in which a hollow-shaped insert member is cast and a water jacket is formed inside the insert member. Furthermore, Patent Document 1 discloses a technique for increasing the strength of the insert member by disposing a filler such as metal particles or sand or providing a reinforcing rib inside the insert member in order to prevent deformation of the insert member. It is disclosed.
JP 2000-230455 A

However, when a filler such as metal particles or sand is disposed inside the insert member as in the technique disclosed in Patent Document 1, a step of taking out the filler after casting is required. As a result, there is a problem that the number of processes increases and productivity decreases.
On the other hand, when the reinforcing rib is provided inside the insert member, a process such as taking out the filler after casting is not required. However, when performing high pressure die casting where the casting pressure is 50 to 80 MPa while securing a relatively large cavity such as a water jacket, there is a possibility that the portion where the reinforcing rib is not provided may be deformed. . In order to prevent such deformation, a plurality of reinforcing ribs may be provided. However, when a plurality of reinforcing ribs are provided, there is a problem that the cooling performance is deteriorated due to disturbance of the flow of cooling water in the water jacket, and a sufficient cooling effect cannot be obtained.

  In general, the cylinder block has the following problems. That is, when the head bolt is screwed into the head bolt hole formed outside the water jacket in the cylinder radial direction and the cylinder block and the cylinder head are fastened, the cylinder bore may be distorted inward. For example, as shown in FIG. 12, when the cylinder block 100 having four head bolt holes 115 around the water jacket 116 at equal intervals is tightened with the head bolts, the cylinder bores 111 are separated from the center of each head bolt hole 115. It was easy to distort toward the bore center O (fourth order deformation). In FIG. 12, a thick line arrow indicates a tightening force acting on the cylinder bore side by tightening the head bolt, and a two-dot chain line indicates a state when the cylinder bore is deformed. When the cylinder bore 111 is distorted inward in this way, the sliding resistance of the piston increases during operation, the followability becomes worse, and problems such as an increase in the consumption of lubricating oil occur.

  Therefore, in order to prevent such deformation of the cylinder bore 111, as shown in FIG. 13, the water jacket 116 is formed deeply to the same extent as the head bolt hole 115 and the piston stroke (for example, 80 to 90 mm). It has been broken. As a result, the force acting on the cylinder bore 111 when the head bolt is tightened can be absorbed and alleviated by the cavity forming the water jacket 116.

  However, when the reinforcing rib is provided inside the insert member as in the technique disclosed in Patent Document 1, the head bolt tightening is performed unless the intentional arrangement or shape of the reinforcing rib is made. The tightening force is easily transmitted to the cylinder bore side through the reinforcing rib provided near the head bolt. Therefore, there has been a problem that the cylinder bore is likely to be deformed.

  Further, in the cylinder bore, since the portion closer to the cylinder head side becomes higher in temperature, it is necessary to actively cool the upper portion of the bore (for example, an area of 20 to 30 mm from the head side). However, if the water jacket is formed as deep as the head bolt or piston stroke, the water jacket will be formed beyond the depth required for cooling. It was not used effectively. That is, the upper part of the cylinder bore that needs to be actively cooled has not been effectively cooled by the cooling water flowing through the water jacket.

  Accordingly, the present invention has been made to solve the above-described problems, and is a closed type capable of preventing the cylinder bore from being deformed when the cylinder block and the cylinder head are fastened, and effectively cooling the upper portion of the cylinder bore. It is an object of the present invention to provide a deck type cylinder block.

In a closed deck type cylinder block comprising a plurality of cylinders in which pistons slide and a water jacket for circulating cooling water for cooling the cylinder, the cylinder head is formed on the outer side in the cylinder radial direction from the water jacket, A head bolt hole used for fastening, an inner cylinder part and an outer cylinder part, arranged around the cylinder and extending downward corresponding to the stroke length of the piston or the length of the head bolt hole A hollow member that forms a water jacket, and the hollow member is provided with a plurality of connecting members that connect the inner wall surface of the inner cylinder part and the inner wall surface of the outer cylinder part in a dispersed manner, wherein the connecting member, and the water flow control member streamlined leading cooling water flowing in the water jacket to the water jacket upper, substantially Includes a circular projection in the form of a cross-section, the circular projection is a front side and rear side are disposed at positions corresponding to respective vertices of a square in a plan view for each bore of said cylinder, said water flow control The member is disposed in the vicinity of an intersection of square diagonal lines formed by connecting the circular protrusions in the plan view for each bore of the cylinder, and the water flow control member is provided at a lower portion of the hollow member. And a water flow suppressing member that extends from the lower portion of the water jacket toward the water flow control member so as to suppress the flow of the cooling water flowing through the lower portion of the water jacket .

  The cylinder block according to the present invention is formed by die casting, in which a hollow member (insert member) forming a water jacket is cast. The hollow member is provided with a plurality of connecting members that connect the inner wall surface of the inner tube portion and the inner wall surface of the outer tube portion. As a result, the mechanical strength of the hollow member can be greatly improved, and even in high-pressure die casting where the casting pressure is 50 to 80 MPa, the hollow member is deformed and partially passes through the cooling water passage in the water jacket. Can be blocked. Therefore, a water jacket having a desired shape can be formed by high-pressure die casting without disposing a filler inside the hollow member.

  In this cylinder block, a water jacket formed by a hollow member extends downward corresponding to the stroke length of the piston or the length of the head bolt hole. A head bolt hole used for fastening with the cylinder head is formed outside the water jacket in the cylinder radial direction. With such a configuration, the tightening force transmitted to the cylinder bore side when the head bolt is tightened can be absorbed and reduced by the cavity forming the water jacket. As a result, it is possible to prevent deformation of the cylinder bore when the cylinder block and the cylinder head are fastened.

  The water jacket is preferably formed as deep as the stroke length of the piston or the length of the head bolt hole. This is because when the water jacket is formed shallower than the stroke length of the piston or the length of the head bolt hole, the tightening force at the time of head bolt tightening is easily transmitted to the cylinder bore as much as the shallow stroke is formed, resulting in deformation of the cylinder bore. This is because it becomes easier. On the other hand, when the water jacket is formed deeper than the stroke length of the piston or the length of the head bolt hole, the cooling water flowing through the lower portion of the water jacket is increased by the amount formed deeper, and the cooling efficiency is deteriorated.

  Here, the connecting member is provided dispersed in the hollow member. Thereby, the tightening force transmitted to the cylinder bore side via the connecting member can be distributed to a plurality of locations without being concentrated at one location. Therefore, even if the inner cylinder part and the outer cylinder part are connected by the connecting member, the cylinder bore can be effectively prevented from being deformed when the cylinder block and the cylinder head are fastened.

Further, by providing the connecting members in such a dispersed manner, the flow of the cooling water in the water jacket can be prevented from being disturbed. That is, even if the connecting member is provided, the dispersive arrangement causes the cooling water to flow smoothly and no separation flow occurs, so that no cavitation occurs and the cooling effect of the cylinder block is not reduced.
Further, the connecting member includes a water flow control member that guides cooling water flowing through the water jacket to the upper portion of the water jacket. Therefore, in this cylinder block, the upper part of the cylinder bore that needs to be actively cooled can be effectively cooled by intentionally guiding the cooling water flowing through the water jacket to the upper part of the water jacket by the water flow suppressing member. it can.

In closed deck type cylinder block according to the present invention, the connecting member, the bottom of said hollow member, said disposed below the water flow control member, for suppressing the flow of the cooling water flowing through the water jacket bottom A water flow suppressing member extending from the lower portion of the water jacket toward the water flow control member is included .

  According to this cylinder block, it is possible to intentionally guide the cooling water flowing through the water jacket to the upper portion of the water jacket by suppressing the flow of the cooling water flowing through the lower portion of the water jacket by the water flow suppressing member. Thereby, the upper part of the cylinder bore which needs to be actively cooled can be cooled more effectively.

In the closed deck type cylinder block according to the present invention, the circular protrusion of the connecting member is disposed at a position avoiding a straight line connecting the center of the head bolt hole and the center of the bore of the cylinder. desirable.

  In this cylinder block, the connecting member is arranged at a position avoiding the straight line connecting the center of the head bolt hole and the center of the bore of the cylinder, so that the tightening force when tightening the head bolt is provided near the head bolt. Therefore, it is possible to reliably prevent transmission to the cylinder bore side via the connecting member. Thereby, the deformation of the cylinder bore can be prevented more reliably when the cylinder block and the cylinder head are fastened.

  Further, in the closed deck type cylinder block according to the present invention, the connecting member is formed by a protrusion provided on at least one of the inner cylinder part or the outer cylinder part so as to protrude inside the hollow member. Is desirable.

  In this way, by forming the connecting member by the protrusion provided so as to protrude inside the hollow member, the connecting member can be easily formed by press molding or the like. Thereby, even if it provides a connection member, productivity of a hollow member does not fall or a production cost does not rise. Therefore, by performing high-pressure die casting by casting a hollow member having such a connecting member, the cylinder bore is prevented from being deformed when the cylinder block and the cylinder head are fastened, and the cooling effect on the upper portion of the cylinder bore is enhanced. The block can be manufactured inexpensively and easily.

  Here, when the connecting member is formed by a projection formed by pressing or the like, the molten metal flows into the inside (recessed portion) of the projection. For this reason, if a protrusion is provided only on the inner cylinder part or only the outer cylinder part of the hollow member, a difference occurs between the pressure of the molten metal received from the inner cylinder part side of the hollow member and the pressure of the molten metal received from the outer cylinder part side. Therefore, the hollow member may be deformed by the pressure difference.

  Therefore, in the closed deck type cylinder block according to the present invention, the connecting member abuts the front end portions of the protrusions provided on both the inner cylinder portion and the outer cylinder portion so as to protrude inside the hollow member. It is preferable that the protrusions formed on the inner cylinder part and the protrusions provided on the outer cylinder part are symmetrical.

  In this way, the connecting member is formed by abutting the tip portions of the protrusions provided on the inner cylinder part and the outer cylinder part so as to protrude inside the hollow member, and the protrusion provided on the inner cylinder part, By making the protrusion provided on the outer cylinder part symmetrical, the pressure of the molten metal received from the inner cylinder part side of the hollow member and the pressure of the molten metal received from the outer cylinder part side can be made equal. Thereby, a deformation | transformation of the hollow member by the pressure of the molten metal at the time of die-casting can be prevented reliably.

  According to the closed deck type cylinder block of the present invention, as described above, the cylinder bore can be prevented from being deformed when the cylinder block and the cylinder head are fastened, and the upper portion of the cylinder bore can be effectively cooled.

  Hereinafter, a most preferred embodiment in which a closed deck type cylinder block according to the present invention is embodied will be described in detail with reference to the drawings. Here, a case where the present invention is applied to a cylinder block used in an in-line four-cylinder engine is illustrated.

[First embodiment]
First, a first embodiment of a cylinder block according to the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a top view showing a schematic configuration of a cylinder block according to the first embodiment. 2 is a cross-sectional view taken along line II-II in FIG.

  As shown in FIG. 1, the cylinder block 10 according to the present embodiment includes four cylinders 12 that slide pistons therein, a water jacket 16 that circulates cooling water that cools the cylinders 12, and the periphery of the water jacket 16. And an outer wall 13 of the block. The cylinder block 10 is a closed deck type, and a cylinder 12 and a block outer wall 13 are connected by a bridge 14.

  As shown in FIG. 2, each cylinder 12 has a cylindrical bore 11 for making a piston slide inside the cylinder 12 and a cylinder liner provided in the cylinder bore 11 to form a sliding surface with the piston ring. 12a.

The block outer wall 13 includes a head bolt hole 15 used for fastening with the cylinder head and a crank bolt hole 17 used for fastening with the crank cap.
The crank bolt hole 17 is provided in the lower part of the block outer wall 13. The crank cap and the cylinder block 10 are fastened by tightening the crank bolt in the crank bolt hole 17 with the crank shaft sandwiched between the crank cap (not shown) and the journal portion 19 of the cylinder block 10. ing.

  As shown in FIG. 1, four head bolt holes 15 are provided around each cylinder bore 11 and outside the water jacket 16 in the cylinder radial direction so as to divide the circumference into four equal parts. Two head bolt holes 15 are provided between the adjacent cylinder bores 11, and the adjacent cylinder bores 11 share the two head bolt holes 15. Each head bolt hole 15 extends downward from the upper deck surface 10a as shown in FIG. The cylinder block 10 and the cylinder head are fastened by bringing the lower surface of the cylinder head (not shown) into contact with the upper deck surface 10a of the cylinder block 10 and tightening the head bolt in the head bolt hole 15. .

  As shown in FIG. 1, the water jacket 16 is provided so as to cover all the four cylinders 12. Further, as shown in FIG. 2, the water jacket 16 extends downward so as to have a length (for example, 80 to 90 mm) that is substantially the same as the length of the head bolt hole 15. Note that the water jacket 16 may be formed to have a length comparable to the stroke length of the piston. The water jacket 16 includes a cooling hollow member 30 that forms a hollow portion for circulating cooling water therein, a plurality of water jacket protrusions 40 for guiding cooling water flowing inside the water jacket 16 toward the cylinder head, A cooling water inlet 46 (see FIG. 1) for introducing cooling water into the water jacket 16 is provided. The water jacket 16 is formed inside the cooling hollow member 30 by casting the cooling hollow member 30 in the cylinder block 10. Inside the water jacket 16, cooling water flows when the engine is operated. Thereby, at the time of engine operation, each cylinder 12 can be cooled from the outer peripheral side with cooling water.

Next, the cooling hollow material 30 according to the present embodiment will be described in detail with reference to FIGS. FIG. 3 is a top view showing a cooling hollow member in the cylinder block. FIG. 4 is an exploded perspective view showing the cooling hollow material. FIG. 5 is a front view showing a cooling hollow material. 3 and 5, the hatched portion A indicates a portion located on a straight line connecting the head bolt hole center X and the cylinder bore center O in the cooling hollow material 30.
As shown in FIG. 3, the cooling hollow member 30 is arranged on each cylinder 12 side to form an inner cylinder part 30 a that forms an inner cylinder, and an outer cylinder that forms an outer cylinder so as to cover the inner cylinder part 30 a from the outside. Part 30b, and a plurality of connecting members 45 (see FIG. 2) for connecting the inner wall surface of the inner cylinder part 30a and the inner wall surface of the outer cylinder part 30b.

The inner cylinder part 30a is provided with the two inner cylinder metal plates 31 and 32, as shown in FIG. And the inner cylinder part 30a is formed by combining each inner cylinder metal plates 31 and 32. As shown in FIG.
Each inner cylinder metal plate 31, 32 includes bent portions 31a, 31b, 32a, 32b formed by bending both ends (upper and lower ends) in the cylinder axial direction to the outside (outer cylinder portion 30b side).
The bent portions 31a and 32a are provided with through holes 41 that are formed in the cylinder axis direction at positions corresponding to the water jacket projections 40. Thereby, when the metal plates 31 to 34 are combined, the lower opening of the water jacket projection 40 communicates with the through hole 41. In place of the through hole 41, a notch may be provided.

The outer cylinder portion 30b includes two outer cylinder metal plates 33 and 34. And the outer cylinder part 30b is formed by combining each outer cylinder metal plates 33 and 34. As shown in FIG.
Each outer cylinder metal plate 33, 34 is provided with bent portions 33a, 33b, 34a, 34b formed by bending both ends (upper and lower ends) in the cylinder axial direction to the inner side (inner cylinder portion 30a side).
The bent portions 33 a and 34 a include a plurality of water jacket protrusions 40. Each water jacket protrusion 40 has a cylindrical shape, and a plurality of water jacket protrusions 40 are provided at predetermined intervals. As shown in FIG. 2, the inside of the water jacket projection 40 is a water channel opening 16a. The upper portion of the water jacket projection 40 is open to the upper deck surface 10 a, and the lower portion of the water jacket projection 40 communicates with the inside of the cooling hollow material 30. With this configuration, the cooling water flowing inside the water jacket 16 can be guided to the water jacket provided in the cylinder head.

  An opening 39 that communicates with the cooling water inlet 46 is provided at one end of the one outer cylinder metal plate 33. The cooling water inlet 46 includes a water intake 36 for taking in the cooling water and a connection member 35 for connecting the water intake 36 to the opening 39. An intake port 36 is joined to one end of the connection member 35, and an opening 39 of the outer cylindrical metal plate 33 is joined to the other end of the connection member 35. In this way, the cooling water inlet 46 is attached to the cooling hollow material 30.

  In addition, each metal plate 31-34 is each press-molded by the predetermined shape as shown in FIG. 4 so that it may become the shape of the water jacket 16 when they are combined. These metal plates 31 to 34 may be made of stainless steel in consideration of corrosion resistance, or may be made of aluminum alloy like the material of the cylinder block 10 in consideration of recyclability. Moreover, welding, brazing, etc. are performed for joining of each metal plates 31-34.

  And the hollow material 30 for cooling is formed by combining and joining such metal plates 31-34. Specifically, the bent portions 31a, 31b, 32a, and 32b and the bent portions 33a, 33b, 34a, and 34b are overlapped and joined together to form the cooling hollow material 30. As described above, the bent portions 31a, 31b, 32a, and 32b and the bent portions 33a, 33b, 34a, and 34b are overlapped at the upper and lower end portions of the cooling hollow material 30, so that the mechanical properties of the cooling hollow material 30 are increased. The overall strength is increased.

  Note that the cooling hollow material provided in the cylinder block 10 is not limited to a plate material, and can be formed using members having various shapes. Here, FIG. 6 is a perspective view showing a cross-section of the cooling hollow material according to the modified example. For example, as shown in FIG. 6, the hollow material 51 for cooling can be formed using a pipe material. However, in order to form the cooling hollow material 51 into the shape of the water jacket 16 using the pipe material, a complicated forming process is required. Therefore, in terms of production efficiency and production cost, the plurality of metal plates 31 to 34 are used. It is preferable to form the cooling hollow material 30 using

As shown in FIG. 4, the connecting member 45 includes a plurality of protrusions 42 a, 43 a, 44 a that are formed on the inner cylinder metal plates 31, 32 so as to protrude outward (on the outer cylinder portion 30 b side), and the outer cylinder metal plate 33. , 34 are provided with a plurality of protrusions 42b, 43b, 44b formed to protrude inward (inner cylinder portion 30a side).
Each protrusion 42a-44a, 42b-43b is formed by the embossing. The protrusions 42a to 44a are provided dispersed on the inner cylindrical metal plates 31 and 32, and the protrusions 42b to 44b are provided distributed on the outer cylindrical metal plates 33 and 34. More specifically, in this embodiment, the protrusion 42a and the protrusion 42b are provided at corresponding positions, the protrusion 43a and the protrusion 43b are provided at corresponding positions, and the protrusion 44a and the protrusion 44b are provided at corresponding positions. It has been.
Further, the protrusion 42a and the protrusion 42b have a substantially symmetric (identical) shape, the protrusion 43a and the protrusion 43b have a substantially symmetric (identical) shape, and the protrusion 44a and the protrusion 44b have a substantially symmetric (identical) shape. Yes.
Then, the protrusion 42a and the protrusion 42b are in contact with each other so as to abut each other, the protrusion 43a and the protrusion 43b are in contact with each other so as to abut each other, and the protrusion 44a and the protrusion 44b are in contact with each other. They are in contact with each other (see FIG. 2). With such a configuration, a plurality of connecting members 45 that connect the inner cylinder part 30a and the outer cylinder part 30b are formed inside the cooling hollow member 30. Further, the mechanical strength of the cooling hollow material 30 is increased by the connecting members 45.

  In the present embodiment, the connecting members 45 are arranged in a dispersed manner in the cooling hollow material 30. This is because the connecting member 45 is constituted by the protrusions 42a to 44a and 42b to 44b arranged in a distributed manner on the metal plates 31 to 34. Below, the detail of each protrusion 42a-44a, 42b-44b which comprises the connection member 45 is demonstrated.

  Each of the protrusions 42a to 44a and 42b to 43b includes a circular protrusion 42a and 42b having a substantially circular cross-sectional shape, a guide streamlined protrusion 43a and 43b having a substantially induced streamline cross-sectional shape (flap shape), and a substantially oval shape. It is comprised from the oblong protrusion 44a, 44b which makes the cross-sectional shape of this.

  The circular protrusions 42a and 42b form a connecting member 45, and have a function of limiting the flow rate of the cooling water by adjusting the construction pitch by providing resistance to the flow of the cooling water flowing inside the water jacket 16. Yes. As shown in FIG. 5, the circular protrusions 42a and 42b are disposed at positions avoiding the straight line connecting the center X of the head bolt hole 15 and the center O of the cylinder bore 11 (regions where the shaded portion A is avoided). ing. Specifically, in the present embodiment, the circular protrusions 42a and 42b are arranged on the front side and the back side for each cylinder bore 11 and at positions corresponding to the vertices of the quadrangle in plan view.

  The induced streamline protrusions 43a and 43b form a connecting member 45 and have a function of efficiently controlling the flow direction of the cooling water without limiting the flow rate of the cooling water flowing through the water jacket 16. Yes. In the present embodiment, the induced streamline protrusions 43a and 43b are provided so as to be inclined upward in the cooling water flow direction. Thereby, the cooling water flowing inside the water jacket 16 can be guided to the upper portion of the water jacket 16. The induced flow linear protrusions 43a and 43b of this embodiment are an example of the “water flow control member” of the present invention. These induced streamline protrusions 43a and 43b are also arranged at positions avoiding the straight line connecting the center X of the head bolt hole 15 and the center O of the cylinder bore 11 (regions where the shaded portion A is avoided). Specifically, in the present embodiment, the induced streamline protrusions 43a and 43b are near the intersections of rectangular diagonal lines formed by connecting the circular protrusions 42 in plan view on the front side and the back side for each cylinder bore 11. Is arranged.

  The elongated round protrusions 44a and 44b form the connecting member 45, and are arranged at the lower part of the water jacket 16 to restrict the flow rate of the cooling water flowing through the lower part of the water jacket 16, while controlling the flow direction of the cooling water. It has a function. In the present embodiment, the elongated round protrusions 44a and 44b are provided so as to be orthogonal to the flow direction of the cooling water, so that the flow direction of the cooling water flowing inside the water jacket 16 can be controlled most effectively. It has become. The long round protrusions 44a and 44b of this embodiment are an example of the “water flow suppressing member” of the present invention. The elongated round protrusions 44a and 44b are also arranged at a position avoiding a straight line connecting the center X of the head bolt hole 15 and the center O of the cylinder bore 11 (a region avoiding the shaded portion A). Specifically, in the present embodiment, the elongated round protrusions 44a and 44b are arranged on the front side and the rear side for each cylinder bore 11 and at a predetermined interval below each induced streamline protrusion 43b in plan view. Has been. The lower ends of the elongated round protrusions 44 a and 44 b reach the lower end of the cooling hollow material 30, so that the flow of cooling water flowing under the water jacket 16 can be reliably suppressed.

Here, an example of changing the above-described protrusion will be described with reference to FIGS. FIG. 7 is a front view showing a protrusion according to a modified example. FIG. 8 is a front view showing a protrusion according to a modified example.
For example, as shown in FIG. 7, by providing the elongated round protrusion 52 along the flow direction of the cooling water flowing inside the water jacket 16, the connection member 45 is formed and the inside of the water jacket 16 flows. The function of limiting the flow rate of the cooling water can also be exhibited.

  Further, as shown in FIG. 8, the streamline protrusion 53 is provided along the flow direction of the cooling water flowing inside the water jacket 16, thereby forming the connecting member 45 and cooling flowing inside the water jacket 16. The function of rectifying the flow of the cooling water can be exhibited by suppressing the occurrence of turbulent flow in the water.

  Next, how the cylinder block 10 configured as described above is cast will be briefly described. In the cylinder block 10, the hollow member 30 forming the water jacket 16 is cast and formed by die casting. That is, by injecting and filling molten metal into the cavity of the mold, the cylinder block 10 is die cast molded by casting the cooling hollow material 30 held in the mold. Here, the die-cast product improves the quality by improving the casting pressure and improves the quality. Therefore, when the casting pressure is lowered, the molding conditions deteriorate and a high-quality product (cylinder block) can be obtained. become unable. For this reason, in this Embodiment, the high pressure die-casting whose casting pressure is 50-80 Mpa is performed. Thereby, the quality of the cylinder block 10 is improved.

  Here, in the cooling hollow material 30, the connecting members 45 formed by the protrusions 42a to 44a and 42b to 43b are dispersedly arranged, and the mechanical strength is increased. In particular, in the present embodiment, the protrusions 37 and 38 have a symmetrical shape (the same shape). Thereby, in the projection part, the pressure of the molten metal received from the inner cylinder part 30a side of the cooling hollow member 30 can be made equal to the pressure of the molten metal received from the outer cylinder part 30b side. In the present embodiment, the metal plates 31, 32 and the bent portions 31a, 31b, 32a, 32b of the metal plates 33, 34 and the bent portions 33a, 33b, 34a, 34b are overlapped and joined. As a result, the mechanical strength at both ends (upper and lower ends) of the cooling hollow material 30 in the cylinder axial direction is increased. Therefore, even in the high-pressure die casting where the casting pressure is 50 to 80 MPa, the deformation of the cooling hollow material 30 due to the pressure of the molten metal can be reliably prevented.

  Therefore, even if the cooling hollow material 30 is cast and high-pressure die casting is performed, the cooling hollow material 30 is not deformed and the cooling water passage is not partially blocked in the water jacket 16. Therefore, the water jacket 16 having a desired shape can be provided even if the cylinder block 10 is formed by high-pressure die casting without disposing a filler inside the cooling hollow material 30. As a result, the closed deck type cylinder block 10 can be manufactured by high-pressure die casting without reducing the productivity.

  Further, since the cylinder block 10 is provided with the water jacket projection 40, when the cylinder block 10 is cast, a part of the mold is inserted into the water jacket projection 40 to fix the cooling hollow material 30 to the mold. It can be done. Thereby, it can cast by positioning appropriately so that the cooling hollow material 30 to be cast does not shift even by the pressure of the molten metal during casting. Therefore, the positional accuracy of the water jacket 16 in the cylinder block 10 can be increased.

  The water jacket projection 40 has a hollow shape, but by inserting a part of the mold into the hollow portion, it can be prevented from being deformed by the pressure of the molten metal even in the high pressure die casting, and the water jacket projection 40 is inserted into the water jacket projection 40. The molten metal does not enter. The water jacket projection 40 may be formed by connecting a pipe to the cooling hollow member 30 or may be formed integrally with the cooling hollow member 30.

  Further, in this cylinder block 10, the positioning accuracy when a part of the mold is inserted into the cooling water inlet 46 and the cooling hollow member 30 is fixed to the mold can be further improved. That is, the cooling hollow member 30 is positioned by the water jacket projection 40 and the cooling water introduction port 46 and is held in the mold, so that the cooling hollow member 30 to be encapsulated is displaced by the pressure of the molten metal during casting. It can prevent more reliably. As a result, the productivity of the cylinder block 10 can be improved, and the position accuracy of the water jacket 16 in the cylinder block 10 can be further increased. The inside of the cooling water inlet 46 is hollow, but by inserting a part of the mold into this hollow portion, even in high pressure die casting, the molten metal is not deformed by the pressure of the molten metal. There is no invasion.

Next, how the cylinder block 10 configured as described above is assembled will be briefly described.
In the cylinder block 10, the cylinder block 10 and the cylinder head are fastened by bringing the lower surface of the cylinder head into contact with the upper deck surface 10 a of the cylinder block 10 and tightening the head bolt in the head bolt hole 15.

Here, in the cylinder block 10, a head bolt hole 15 used for fastening with the cylinder head is formed outside the water jacket 16 in the cylinder radial direction. Thereby, the tightening force transmitted to the cylinder bore 11 when the head bolt is tightened can be absorbed by the cavity forming the water jacket 16 and alleviated. As a result, it is possible to prevent the cylinder bore 11 from being deformed when the cylinder block 10 and the cylinder head are fastened.
Further, the water jacket 16 is extended downward so as to have a length comparable to the length of the head bolt hole 15 or the stroke length of the piston. Here, when the water jacket 16 is formed shallower than the length of the head bolt hole 15 or the stroke length of the piston, the tightening force at the time of tightening the head bolt is easily transmitted to the cylinder bore 11 by the amount formed shallower. Deformation of the cylinder bore 11 is likely to occur. On the other hand, when the water jacket 16 is formed deeper than the length of the head bolt hole 15 or the stroke length of the piston, the cooling water flowing through the lower portion of the water jacket 16 is increased by the depth of the water jacket 16 and the cooling efficiency is deteriorated. . On the other hand, the water jacket 16 according to the present embodiment is formed as deep as the length of the head bolt hole 15 or the stroke length of the piston. Thereby, both the deformation of the cylinder bore 11 and the deterioration of the cooling efficiency can be effectively prevented.

  Further, in this cylinder block 10, the connecting members 45 are provided dispersed inside the cooling hollow material 30. Thereby, the tightening force transmitted to the cylinder bore 11 side via the connecting member 45 can be dispersed at a plurality of locations without being concentrated at one location. Therefore, even if the inner cylinder part 30a and the outer cylinder part 30b are connected by the connecting member 45, the cylinder bore 11 can be effectively prevented from being deformed when the cylinder block 10 and the cylinder head are fastened.

  Further, in this cylinder block 10, all the protrusions 42 a to 44 a and 42 b to 43 b (connection member 45) are located on the straight line connecting the center X of the head bolt hole 15 and the center O of the cylinder bore 11 (shaded). (Area avoiding part A). By arranging in this way, it is possible to reliably prevent the tightening force at the time of head bolt tightening from being transmitted to the cylinder bore 11 side via the connecting member 45 provided near the head bolt. Thereby, the deformation | transformation of the cylinder bore 11 at the time of the fastening of the cylinder block 10 and a cylinder head can be prevented more reliably.

Next, the state of the cooling water flowing through the water jacket 16 of the cylinder block 10 configured as described above will be briefly described.
In the cylinder block 10, cooling water is introduced into the water jacket 16 from the introduction port 46 during engine operation. The cooling water introduced into the water jacket 16 flows in the cylinder radial direction while cooling the cylinders 12 in order. The cooling water flows from a plurality of water jacket protrusions 40 provided on the upper portion of the water jacket 16 to a water jacket provided on the cylinder head side.

  Here, in the cylinder block 10, the connection members 45 are provided in a distributed manner. As described above, since the connecting members 45 are provided in a dispersed manner, it is possible to prevent the flow of the cooling water in the water jacket 16 from being disturbed. That is, even if the connecting member 45 is provided, since the cooling water flows smoothly and no separation flow is generated, no cavitation occurs and the cooling effect of the cylinder block 10 is not reduced. .

  Further, in the cylinder block 10, the cooling water flowing inside the water jacket 16 is guided to the upper portion of the water jacket 16 by the induced streamline protrusions 43 a and 43 b and the long round protrusions 44 a and 44 b forming the connecting member 45. The flow rate of the cooling water flowing through the lower portion of the water jacket 16 is limited (see the thick arrow in FIG. 6). Thus, since the cooling water flowing inside the water jacket 16 can be intentionally guided to the upper part of the water jacket 16, the upper part of the cylinder bore 11 that needs to be actively cooled can be effectively cooled.

  As described above in detail, according to the cylinder block 10 according to the present embodiment, the cooling hollow material 30 is deformed and the cooling water passage is partially formed in the water jacket 16 even in high-pressure die casting. Blocking can be prevented. Further, it is possible to effectively prevent the deformation of the cylinder bore 11 when the cylinder block 10 and the cylinder head are fastened. Furthermore, it is possible to effectively cool the upper portion of the cylinder bore 11 that needs to be actively cooled (for example, an area of 20 to 30 mm from the head side).

[Second Embodiment]
Next, a second embodiment of the cylinder block according to the present invention will be described with reference to FIG. FIG. 9 is a front view showing a cooling hollow member provided in the cylinder block according to the second embodiment.
In the cylinder block according to this embodiment, the position and shape of each protrusion forming the connecting member 45 are different from those of the above-described embodiment. That is, in this embodiment, as shown in FIG. 9, the elongated round protrusions 44a and 44b of the first embodiment are extended upward to be integrated with the induced streamline protrusions 43a and 43b, thereby achieving both functions. A coupling protrusion 60 is formed.

  As described above, the elongated round protrusions 44a and 44b are extended upward to be integrated with the induction streamline protrusions 43a and 43b, so that the flow of the cooling water flowing through the lower portion and the middle portion of the water jacket 16 can be more reliably obtained. The cooling water flowing inside the water jacket 16 can be reliably guided to the upper portion of the water jacket 16 (see the thick arrow in FIG. 9). Thereby, the cylinder bore 11 upper part which needs to be actively cooled can be cooled more effectively.

[Third embodiment]
Next, a third embodiment of the cylinder block according to the present invention will be described with reference to FIG. FIG. 10 is a front view showing a cooling hollow member provided in the cylinder block according to the third embodiment.
The cylinder block according to the present embodiment is different from that of the above-described embodiment in that a protrusion forming the connecting member 45 is further added to the configuration of the first embodiment. That is, in the present embodiment, as shown in FIG. 10, the position avoiding the straight line connecting the center X of the head bolt hole 15 and the center O of the cylinder bore 11 (region avoiding the shaded portion A), Between the adjacent cylinder bores 11, induced flow linear protrusions 43 a and 43 b and long round protrusions 44 a and 44 b are also provided.

  In this manner, by adding the induction streamline protrusions 43a and 43b and the elongated round protrusions 44a and 44b, the mechanical strength of the cooling hollow member 30 is further increased, and the deformation of the cooling hollow member 30 is more reliably performed. Can be prevented. In addition, the flow of cooling water flowing through the lower portion of the water jacket 16 is more reliably suppressed by the induction streamline protrusions 43a and 43b and the elongated round protrusions 44a and 44b, so that the cooling water flowing through the water jacket 16 is allowed to flow. 16 can be reliably guided to the upper part of 16 (see the thick arrow in FIG. 10). Thereby, the cylinder bore 11 upper part which needs to be actively cooled can be cooled more effectively.

[Fourth embodiment]
Next, a fourth embodiment of the cylinder block according to the present invention will be described with reference to FIG. FIG. 11 is a front view showing a cooling hollow member provided in the cylinder block according to the fourth embodiment.
The cylinder block according to the present embodiment is different from that of the above-described embodiment in that a protrusion forming the connecting member 45 is further added to the configuration of the first embodiment. That is, in the present embodiment, as shown in FIG. 11, the position avoiding the straight line connecting the center X of the head bolt hole 15 and the center O of the cylinder bore 11 (region avoiding the shaded portion A), Circular protrusions 42 a and 42 b are also provided between adjacent cylinder bores 11.

  Thus, by adding the circular protrusions 42a and 42b, the mechanical strength of the cooling hollow member 30 can be further increased, and the deformation of the cooling hollow member 30 can be prevented more reliably. Moreover, resistance can be given to the flow of the cooling water flowing inside the water jacket 16, and the flow rate of the cooling water can be further limited by adjusting the construction pitch.

  It should be noted that the above-described embodiment is merely an example and does not limit the present invention in any way, and various improvements and modifications can be made without departing from the scope of the invention. An example is shown below.

  For example, the shape of the cylinder block 10 is not limited to the shape of the protrusions 42a to 44a, 42b to 43b, 52, 53, and 60 shown in the above embodiment, and the flow of cooling water is controlled or suppressed using protrusions of other shapes. May be.

  In the embodiment described above, the connecting member 45 is formed by the protrusions 42a to 44a provided on the inner cylindrical metal plates 31 and 32 and the protrusions 42b to 43b provided on the outer cylindrical metal plates 33 and 34. Protrusions can be provided only on the inner cylinder metal plates 31 and 32 or the outer cylinder metal plates 33 and 34, and the connecting member 45 can be formed by the projections. Further, the connecting member 45 is not provided with protrusions on the inner cylindrical metal plates 31 and 32 and the outer cylindrical metal plates 33 and 34, but is formed of a member different from the inner cylindrical metal plates 31 and 32 and the outer cylindrical metal plates 33 and 34. You can also

  Further, when the cooling hollow member 30 is formed of a metal plate, the number of metal plates to be used is not limited to four. For example, two metal plates (one inner metal part and one outer cylinder part each of one metal) It is also possible to use three metal plates (one inner plate portion is composed of one metal plate and outer cylinder portion is composed of two metal plates), or four or more metal plates.

  Further, a gas vent groove may be provided in the protrusions 42a to 44a, 42b to 43b, and 60 shown in the above embodiment so that the gas can be vented efficiently. Thereby, generation | occurrence | production of a casting defect can be prevented.

  In the above-described embodiment, the case where the present invention is applied to an in-line four-cylinder engine is illustrated, but the present invention can also be applied to engines other than the in-line four-cylinder engine. For example, the present invention can be applied to an engine in which the number of cylinders is increased or decreased, such as a V-type or a horizontally opposed cylinder.

  Further, it is not limited to the positions of the protrusions 42a to 44a, 42b to 43b, 52, 53, and 60 shown in the above embodiment, and other than the straight line connecting the center X of the head bolt hole 15 and the center O of the cylinder bore 11 is avoided. The protrusions 42a to 44a, 42b to 43b, 52, 53, and 60 can be provided at the positions (regions where the shaded portion A is avoided). Note that, even in the region included in the shaded portion A, the shaded portion is sufficient if the tightening force at the time of fastening the head bolt can be sufficiently suppressed from being transmitted to the cylinder bore 11 side via the connecting member 45. It is also possible to form a small number of protrusions in the region included in the part A.

It is a top view which shows schematic structure of the cylinder block which concerns on 1st embodiment. It is sectional drawing in the II-II line of FIG. It is a top view which shows the hollow material for cooling in a cylinder block. It is a disassembled perspective view which shows the hollow material for cooling. It is a front view which shows the hollow material for cooling. It is the perspective view which showed the cross section of the hollow material for cooling which concerns on the example of a change. It is a front view which shows the protrusion which concerns on the example of a change. It is a front view which shows the protrusion which concerns on the example of a change. It is a front view which shows the hollow material for cooling of the cylinder block which concerns on 2nd embodiment. It is a front view which shows the hollow material for cooling of the cylinder block which concerns on 3rd embodiment. It is a front view which shows the hollow material for cooling of the cylinder block which concerns on 4th embodiment. It is a top view which shows schematic structure of the cylinder block which concerns on a prior art example. It is sectional drawing in the XIII-XIII line | wire of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Cylinder block 11 Cylinder bore 12 Cylinder 13 Block outer wall 14 Bridge 15 Head bolt hole 16 Water jacket 30 Cooling hollow material 30a Inner cylinder part 30b Outer cylinder part 42 Circular protrusion 43 Guide stream linear protrusion 44 Oval-shaped protrusion 45 Connection member

Claims (4)

In a closed deck type cylinder block comprising a plurality of cylinders in which pistons slide, and a water jacket for circulating cooling water for cooling the cylinders,
A head bolt hole formed on the outer side in the cylinder radial direction from the water jacket, and used for fastening with the cylinder head;
A hollow member comprising an inner cylinder part and an outer cylinder part, disposed around the cylinder, and forming a water jacket extending downward corresponding to the stroke length of the piston or the length of the head bolt hole; Have
The hollow member is provided with a plurality of connecting members that connect the inner wall surface of the inner cylinder part and the inner wall surface of the outer cylinder part in a dispersed manner,
The connecting member includes a streamlined water flow control member for guiding cooling water flowing through the water jacket to the upper portion of the water jacket, and a circular protrusion having a substantially circular cross-sectional shape ,
The circular protrusions are arranged on the front side and the back side for each bore of the cylinder and at positions corresponding to the vertices of the quadrangle in plan view,
The water flow control member is disposed in the vicinity of an intersection of diagonal lines formed by connecting the circular protrusions in the plan view for each bore of the cylinder ,
The connecting member is disposed at a lower portion of the hollow member and immediately below the water flow control member, and extends from the lower portion of the water jacket toward the water flow control member so as to suppress a flow of cooling water flowing through the lower portion of the water jacket. A closed deck type cylinder block including a water flow suppressing member . In the closed deck type cylinder block according to claim 1 ,
Of the connecting members , the circular protrusion is disposed at a position avoiding a straight line connecting the center of the head bolt hole and the center of the bore of the cylinder. In the closed deck type cylinder block according to claim 1 or 2 ,
A closed deck type cylinder block, wherein the connecting member is formed on at least one of the inner cylinder part or the outer cylinder part by a protrusion provided to protrude inside the hollow member. In the closed deck type cylinder block according to claim 3 ,
The connecting member is formed by abutting the tip portions of the protrusions provided to protrude inside the hollow member on both the inner cylinder part and the outer cylinder part,
A closed deck type cylinder block characterized in that a protrusion provided on the inner cylinder part and a protrusion provided on the outer cylinder part are symmetrical.

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