JP2010196601A - Closed deck type cylinder block - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a closed deck type cylinder block being manufactured at low cost and providing high strength and cooling effect. <P>SOLUTION: The cylinder block 10 is a closed deck type cylinder block including a plurality of cylinders in which pistons slide, and a water jacket in which cooling water cooling the cylinders flows. The cylinder block 10 includes a cooling hollow material 30 including an inner cylinder part 30a and an outer cylinder part 30b, and disposed around the cylinder to form a water jacket, and a passage forming member 20 disposed at an inside of a cylinder wall defining each bore of the cylinder and communicated to the cooling hollow material 30 to form a cooling path between bores. The cooling hollow material 30 and the passage forming member 20 are casted by die casting with the same connected each other. <P>COPYRIGHT: (C)2010,JPO&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.

  By the way, since the combustion heat is transmitted from the bores on both sides to the cylinder wall that partitions each cylinder bore of the cylinder block, high cooling performance is required. However, it has been difficult to obtain appropriate cooling in a narrow region between the bores of the cylinder. As a technique that satisfies these requirements, for example, Patent Document 1 discloses a technique in which a cooling water channel is machined by a drill on a cylinder wall.

JP 2001-107801 A

  However, according to the technique described in Patent Document 1, since the cooling water channel is formed in the cylinder wall by machining, there is a problem that the cost increases. Further, since the shape of the cooling passage is limited to a linear shape that is easy to machine, there is a problem that it is difficult to obtain a necessary cooling effect. Furthermore, there is a concern about strength problems because stress cracking or the like starting from the opening end of the cooling passage is likely to occur after processing.

  Therefore, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a closed deck type cylinder block that can be manufactured at low cost and can obtain high strength and a cooling effect.

  A closed deck type cylinder block according to the present invention, which has been made to solve the above-mentioned problems, includes a plurality of cylinders in which pistons slide, and a water jacket for circulating cooling water for cooling the cylinders. In the deck type cylinder block, an inner cylinder part and an outer cylinder part are provided, and are arranged around the cylinder and formed in a cylinder wall that partitions each bore of the cylinder, and a hollow member that forms a water jacket. A passage forming member that communicates with the hollow member to form a cooling passage between bores, and the hollow member and the passage forming member are cast by die casting in a connected state. To do.

  In the cylinder block according to the present invention, the hollow member forming the water jacket and the passage forming member forming the inter-bore cooling passage are cast by die casting. The passage forming member communicates with the hollow member. Therefore, by introducing the cooling water into the water jacket, a part of the cooling water can be allowed to flow through the inter-bore cooling passage to actively cool between the bores that require high cooling performance.

  According to this cylinder block, since the bore cooling passage is formed by die casting, post-processing such as machining can be omitted. Thereby, the manufacturing cost of a cylinder block can be reduced. Moreover, the shape of the inter-bore cooling passage can be easily changed by changing the shape of the passage forming member. Thereby, the cooling effect required for the required site | part between bores can be acquired. Furthermore, since the occurrence of stress cracking due to the influence of machining or the like can be prevented, the strength of the cylinder block can be improved. Moreover, since the hollow member and the channel | path formation member are connected, the intensity | strength of a hollow member can be improved. As a result, even in high-pressure die casting where the casting pressure is 50 to 80 MPa, it is possible to prevent the hollow member from being deformed and partially blocking the cooling water passage in the water jacket.

  By the way, generally, in the water jacket, the flow rate of the cooling water differs depending on the height position. This is due to the fact that the required cooling effect differs depending on the height position and that the cooling water in the jacket is normally discharged from the upper part of the jacket to the head side.

  Therefore, in the cylinder block according to the present invention, it is desirable that one of the end portions of the passage forming member communicates with the hollow member at a height position different from the other.

  Thus, by making one of the end portions of the passage forming member communicate with the hollow member at a height position different from the other, a water pressure difference can be intentionally generated at each end portion of the passage forming member. By generating the water pressure difference in this way, the speed of the cooling water flowing through the passage forming member can be increased, and a higher cooling effect can be obtained between the bores.

  In the closed deck type cylinder block according to the present invention, a plurality of connecting members for connecting the inner wall surface of the inner cylinder part and the inner wall surface of the outer cylinder part are provided in the hollow member in a dispersed manner. Is desirable.

  Thus, the mechanical strength of the hollow member can be greatly improved by providing 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 to the hollow member. Can do. As a result, even in high-pressure die casting, it is possible to more reliably prevent the hollow member from being deformed.

  According to the closed deck type cylinder block according to the present invention, as described above, it can be manufactured at low cost, and high strength and cooling effect can be obtained.

It is a top view which shows schematic structure of the cylinder block which concerns on embodiment of this invention. It is a perspective view which shows the hollow material for cooling and the channel | path formation member cast by the cylinder block. It is a disassembled perspective view which shows the hollow material for cooling and the passage formation member. It is an expanded sectional view which shows the cooling hollow member. It is an expanded sectional view showing the passage formation member. It is an expanded sectional view which shows the mode after the assembly | attachment of the same passage formation member. It is an expanded sectional view which shows the hollow material for cooling and the channel | path formation member cast by the cylinder block which concerns on 2nd embodiment. It is an expanded sectional view which shows the hollow material for cooling and the channel | path formation member which concern on the example of a change.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a preferred embodiment in which a closed deck type cylinder block according to the 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 will be described.

  First, the overall configuration of the cylinder block according to the present embodiment 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 an embodiment of the present invention. FIG. 2 is a perspective view showing a cooling hollow member and a passage forming member cast in the cylinder block.

  As shown in FIG. 1, the cylinder block 10 includes four cylinders 12 arranged in series, a water jacket 16 that circulates cooling water that cools the cylinder 12, and a block outer wall 13 that forms the periphery of the water jacket 16. It has. 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.

Each cylinder 12 has a cylinder bore 11 for making a piston slide inside the cylinder 12 in a cylindrical shape. Each cylinder bore 11 is partitioned by a cylinder wall 12a.
The block outer wall 13 includes a head bolt hole 15 used for fastening with a cylinder head (not shown). The cylinder block 10 and the cylinder head are fastened by bringing the lower surface of the cylinder head into contact with the upper surface of the cylinder block 10 and tightening the head bolt in the head bolt hole 15.

The water jacket 16 is provided so as to cover all of the four cylinders 12. As shown in FIG. 2, the water jacket 16 is formed by a cooling hollow material 30 that forms a hollow portion through which cooling water flows.
As shown in FIG. 1, the water jacket 16 communicates with an inter-bore cooling passage 17 for cooling between the bores 11 of the cylinder 12. The inter-bore cooling passage 17 is provided inside the cylinder wall 12a so as to pass between the bores. As shown in FIG. 2, the inter-bore cooling passage 17 is formed by a passage forming member 20 arranged inside the cylinder wall 12a. And the hollow material 30 for cooling and the channel | path formation member 20 are cast by die-casting in the connected state.

  Here, the cooling hollow material 30 and the passage forming member 20 of the present embodiment will be described in detail with reference to FIGS. FIG. 3 is an exploded perspective view showing the cooling hollow member and the passage forming member according to the present embodiment. FIG. 4 is an enlarged cross-sectional view showing the cooling hollow member. FIG. 5 is an enlarged cross-sectional view showing the passage forming member. FIG. 6 is an enlarged cross-sectional view showing a state after the passage forming member is assembled.

  As shown in FIG. 3, the cooling hollow member 30 is arranged on the inner side (cylinder 12 side) to form an inner cylinder part 30a that forms an inner cylinder, and an outer cylinder that covers the inner cylinder part 30a from the outside. Cooling water is introduced into the inside of the outer cylinder portion 30b, a plurality of connecting members 45 (see FIG. 4) that connect the inner wall surface of the inner cylinder portion 30a and the inner wall surface of the outer cylinder portion 30b, and the cooling hollow material 30. And a cooling water inlet 46. The cooling hollow material 30 of the present embodiment corresponds to the “hollow member” of the present invention.

  The inner cylinder portion 30a is composed of two inner cylinder metal plates 31 and 32. Each inner cylinder metal plate 31 and 32 is bent part 31a, 31b, 32a, 32b formed by bending the cylinder axial direction both ends (upper and lower ends) outward, and from the side to the outside (outer cylinder part 30b side). A plurality of protruding projections 37 and a through hole 21 through which the passage forming member 20 can be inserted are provided.

  The bent portions 31a and 32a are provided with through-holes 41 formed so as to penetrate in the cylinder axial direction at positions corresponding to water jacket projections 40 of the outer cylinder portion 30b described later. 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.

  One through hole 21 is provided at a position corresponding to the space between the bores 11 in each of the inner cylindrical metal plates 31, 32, that is, a total of six inner cylindrical metal plates 31, 32. All these through holes 21 are formed at the same height corresponding to the upper part of the water jacket 16.

  The outer cylinder part 30b is comprised by the two outer cylinder metal plates 33 and 34. As shown in FIG. Each outer cylinder metal plate 33, 34 is formed by bending both ends (upper and lower ends) in the cylinder axial direction to the inner side (bending portions 33a, 33b, 34a, 34b) and projecting toward the inner side (inner cylinder portion 30a side). And a plurality of projections 38. Further, one outer cylinder metal plate 33 is provided with an opening 39 communicating with the cooling water inlet 46.

  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. The upper portion of the water jacket projection 40 is open to the upper deck surface of the cylinder block 10, and the lower portion of the water jacket projection 40 is formed through the through holes 41 of the inner cylinder metal plates 31 and 32 of the cooling hollow material 30. It communicates with the inside. With such a configuration, the cooling water flowing inside the water jacket 16 can be guided from the water jacket projection 40 to the cylinder head.

  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. In other words, the water intake 36 communicates with the opening 39 through the connection member 35. During engine operation, the cooling water taken into the water intake 36 flows from the opening 39 to the inside of the cooling hollow material 30 (water jacket 16).

  Each of the metal plates 31 to 34 is press-formed into a predetermined shape so that the shape of the water jacket 16 is obtained when they are combined. Note that these metal plates 31 to 34 may be made of stainless steel in consideration of corrosion resistance, or may be made of aluminum alloy in the same manner as 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, as shown in FIG. 4, the bent portions 31a, 31b, 32a, and 32b and the bent portions 33a, 33b, 34a, and 34b are overlapped and joined to form the cooling hollow material 30. ing. As described above, the bent portions 31a, 31b, 32a, and 32b and the bent portions 33a, 33b, 34a, and 34b are overlapped with each other at the upper and lower ends of the cooling hollow material 30. The overall strength is increased.

The connecting member 45 is composed of a plurality of protrusions 37 protruding outward from the inner cylindrical metal plates 31 and 32 and a plurality of protrusions 38 protruding outward from the outer cylindrical metal plates 33 and 34. Has been.
The protrusions 37 and 38 are provided in a distributed manner by embossing, and the protrusion 37 and the protrusion 38 have a substantially symmetrical (identical) shape. Then, the protrusion 37 and the protrusion 38 are in contact with each other so that the tip portions abut against each other. With such a configuration, a plurality of connecting members 45 that connect the inner cylinder part 30a and the outer cylinder part 30b are provided in the cooling hollow member 30 in a dispersed manner. In the present embodiment, each of the protrusions 37 and 38 has a substantially circular cross-sectional shape, and resistance is given to the flow of the cooling water flowing inside the water jacket 16, and the construction pitch is adjusted to adjust the cooling water. It has a function to limit the flow rate.

  As shown in FIG. 5, the passage forming member 20 is a straight pipe material. A bulge-shaped positioning portion 20a that is bent so as to bulge outward is formed at a position on the center side by a predetermined distance from both ends of the passage forming member 20. Then, when the inner cylinder metal plates 31 and 32 are assembled to form the inner cylinder portion 30a, both end portions of the passage forming member 20 are inserted into the through holes 21 of the inner cylinder metal plates 31 and 32 as shown in FIG. Inserted into. When the positioning portion 20a of the passage forming member 20 contacts the inner wall surface of the inner cylindrical metal plates 31, 32, the passage forming member 20 and the inner cylindrical metal plates 31, 32 are positioned. After that, the passage forming member 20 is caulked to the outer wall surface of each inner cylinder metal plate 31, 32 by protruding the portion 20 b protruding outward from each inner cylinder metal plate 31, 32 of the passage forming member 20. 30a is fixed. In the present embodiment, both ends of the passage forming member 20 communicate with the cooling hollow material 30 at the same height as shown in FIG.

  Next, how the cylinder block 10 configured as described above is cast will be briefly described. In the cylinder block 10, the cooling hollow material 30 that forms the water jacket 16 and the passage forming member 20 that forms the inter-bore cooling passage 17 are cast by die casting in a connected state. That is, by injecting and filling molten metal into the mold cavity, the cooling hollow member 30 and the passage forming member 20 held in the mold are cast and the cylinder block 10 is die-cast. By the way, the die casting product improves the molding condition and improves the quality by increasing the casting pressure. Therefore, when the casting pressure is lowered, the molding condition deteriorates and a high quality product (cylinder block) can be obtained. Disappear. 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 37 and 38 are dispersedly arranged, and the mechanical strength is increased. Further, the protrusions 37 and 38 have a symmetrical shape (the same shape), and in the protrusion part, the pressure of the molten metal received from the inner cylinder part 30a side of the cooling hollow material 30 and the pressure of the molten metal received from the outer cylinder part 30b side Are equivalent. The bent portions 31a, 31b, 32a, and 32b of the metal plates 31 and 32 and the bent portions 33a, 33b, 34a, and 34b of the metal plates 33 and 34 are overlapped and joined to each other. The mechanical strength at both ends (upper and lower ends) in the cylinder axial direction is increased. Further, the cooling hollow member 30 and the passage forming member 20 are connected, and the strength is further improved. With such a configuration, deformation of the cooling hollow material 30 due to the pressure of the molten metal can be reliably prevented even in high-pressure die casting where the casting pressure is 50 to 80 MPa.

  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, according to the cylinder block 10, since the bore cooling passage 17 is formed by die casting, post-processing such as machining can be omitted. Thereby, the manufacturing cost of a cylinder block can be reduced. Further, the shape of the inter-bore cooling passage 17 can be easily changed by changing the shape of the passage forming member 20. Thereby, the cooling effect required for the required site | part between bores can be acquired. Furthermore, since the occurrence of stress cracking due to the influence of machining or the like can be prevented, the strength of the manufactured cylinder block 10 can be improved.

  In the cylinder block 10, a portion 20 b of the passage forming member 20 that protrudes outward from the inner cylindrical metal plates 31, 32 is caulked to the outer wall surface of each inner cylindrical metal plate 31, 32. 20 is fixed to the inner cylinder part 30a. Thereby, it can prevent that a molten metal penetrate | invades from the clearance gap between the penetration holes 21 provided in each inner cylinder metal plate 31 and 32 at the time of casting.

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. Thereafter, the cooling water flows from the plurality of water jacket protrusions 40 provided on the upper portion of the water jacket 16 to the water jacket provided on the cylinder head side.

  Here, in this cylinder block 10, the connecting 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. .

  By the way, since the combustion heat is transmitted from the bores 11 on both sides to the cylinder wall 12a that partitions the cylinder bores 11 of the cylinder block 10, high cooling performance is required. In contrast, in the cylinder block 10, the passage forming member 20 that forms the inter-bore cooling passage 17 communicates with the cooling hollow material 30 that forms the water jacket 16. Thereby, when cooling water is introduced into the water jacket 16, a part of the cooling water flows into the inter-bore cooling passage 17, and the space between the bores (cylinder wall 12a) can be positively cooled.

  As described above in detail, according to the cylinder block 10 according to the present embodiment, the machining process for forming the inter-bore cooling passage 17 is omitted and manufactured at low cost, and deformation of the cooling hollow material 30 is prevented. Thus, a desired water jacket 16 can be formed. Moreover, according to this cylinder block 10, while exhibiting high intensity | strength and preventing a stress crack etc., the effective cooling effect can be acquired also between the bores.

[Second Embodiment]
Next, a second embodiment of the cylinder block according to the present invention will be described with reference to FIG. FIG. 7 is an enlarged cross-sectional view showing a cooling hollow material and a passage forming member cast in a cylinder block according to the second embodiment. In addition, about the component same as the thing of the said embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

In the cylinder block according to the present embodiment, as shown in FIG. 7, one of the end portions of the passage forming member 50 is placed on the inner cylindrical metal plates 31 and 32 of the cooling hollow material 30 at a height position different from the other. It differs from that of the first embodiment in that it communicates.
Specifically, in the present embodiment, the through hole 52 provided in the inner cylinder metal plate 31 is located below the through hole 51 provided in the inner cylinder metal plate 32.
The passage forming member 50 includes a stepped portion 50a formed near the center. Then, both ends of the passage forming member 50 are inserted through the through holes 51 and 52 having different height positions from the vertical direction of the inner cylindrical metal plates 31 and 32.

  Here, generally, in the water jacket 16, the cooling water flows at different speeds depending on the height position. This is due to the fact that the required cooling effect differs depending on the height position, and that the cooling water in the jacket 16 is normally discharged from the upper part of the jacket to the head side. Therefore, in the present embodiment, one end of the passage forming member 50 is communicated with the cooling hollow material 30 at a height position different from the other, thereby intentionally supplying water pressure to each end of the passage forming member 50. Differences can be generated. By generating the water pressure difference in this manner, the speed of the cooling water flowing through the passage forming member 50 can be increased, and a higher cooling effect can be obtained between the bores 11. Further, both ends of the passage forming member 50 can be inserted into the through holes 51 and 52 having different height positions from the vertical direction of the inner cylindrical metal plates 31 and 32 by using the stepped portion 50a. There is no difficulty in assembling the member 50 to the inner cylindrical metal plates 31 and 32.

[Example of change]
Here, a modified example of the second embodiment will be described with reference to FIG. FIG. 8 is an enlarged cross-sectional view showing a cooling hollow member and a passage forming member according to a modified example. In addition, about the component same as the thing of the said embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  As shown in FIG. 8, the passage forming member 60 according to the modified example does not include the stepped portion 50 a, and is obtained by cutting a straight pipe material obliquely. And the inner cylinder metal plates 31 and 32 are formed with oblique hole shapes 61 and 62 having different height positions so that the passage forming member 60 can be obliquely inserted. In this modified example, the bulge-shaped positioning part 20a is not formed.

  According to this modified example, since the passage forming member 60 is obliquely inserted into the insertion holes 61 and 62 of the inner cylindrical metal plates 31 and 32, the assembly work becomes more difficult than that of the second embodiment. This is advantageous in that the processing of the stepped portion 50a can be omitted. In this modified example, since the positioning portion 20a is not provided, the positioning function is lost, but it is advantageous in that the processing operation of the passage forming member 60 can be further facilitated.

  It should be noted that the above-described embodiments and modifications thereof are merely examples and do 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.

  In the above-described embodiment, the case where the present invention is applied to an in-line four-cylinder engine has been described, 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 V-type or horizontally opposed, and the number of cylinders.

  Further, in the above-described embodiment, the connecting member 45 is formed by the protrusion 37 provided on the inner cylinder metal plates 31 and 32 and the protrusion 38 provided on the outer cylinder metal plates 33 and 34, but the inner cylinder metal plate 31. , 32 or the outer cylindrical metal plates 33, 34 may be provided with a protrusion, and the connecting member 45 may be formed by the protrusion. 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

  In the above-described embodiment, the case where the cooling hollow member 30 is configured by four metal plates has been described. However, the present invention is not limited to this. For example, two metal plates (an inner cylinder portion and an outer cylinder portion are provided). Hollow material for cooling by three metal plates (one inner plate part is composed of one metal plate and outer cylinder part is composed of two metal plates), or four or more metal plates. May be configured.

  Further, in the above-described embodiment, the circular protrusions 37 and 38 having a substantially circular cross-sectional shape are employed. However, the present invention is not limited to this. For example, an induced streamline-shaped protrusion having a substantially induced streamline cross-sectional shape (flap shape) In addition, an oval projection having a substantially oval cross-sectional shape may be employed.

  In addition, a gas vent groove may be provided in the protrusions 37 and 38 shown in the above embodiment so that gas can be vented efficiently. Thereby, generation | occurrence | production of a casting defect can be prevented.

DESCRIPTION OF SYMBOLS 10 Cylinder block 11 Cylinder bore 12 Cylinder 12a Cylinder wall 13 Block outer wall 14 Bridge 16 Water jacket 17 Cooling passage 20 between bores Passage formation member 20a Positioning part 20b Extrusion part 21 Insertion hole 30 Hollow material for cooling (hollow member)
30a Inner cylinder part 30b Outer cylinder part 37 Projection 38 Projection 45 Connection member

Claims (3)

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 hollow member comprising an inner cylinder part and an outer cylinder part, and arranged around the cylinder to form a water jacket;
A passage forming member that is disposed inside a cylinder wall that partitions each bore of the cylinder and that forms a cooling passage between the bores in communication with the hollow member;
A closed deck type cylinder block, wherein the hollow member and the passage forming member are cast by die casting in a connected state. In the closed deck type cylinder block according to claim 1,
One of the end portions of the passage forming member communicates with the hollow member at a height position different from the other, and is a closed deck type cylinder block. In the closed deck type cylinder block according to claim 1 or 2,
A closed deck type cylinder block characterized in that a plurality of connecting members for connecting the inner wall surface of the inner cylinder part and the inner wall surface of the outer cylinder part are distributed in the hollow member.

Images