JP4407831B2 - Open deck cylinder block - Google Patents

Description

The present invention, when assembling the cylinder head open deck type cylinder block via a gasket, in which about the open deck type cylinder block capable of suppressing the deformation of the cylinder bore located at both ends in the longitudinal direction of the cylinder block .

  In general, as shown in FIG. 9, the cylinder block of the engine has a plurality of cylinder bores 3 to 6 arranged substantially linearly on the mating surface 7 with the cylinder head in order to improve the cooling efficiency and reduce the weight of the engine. An open deck type cylinder block 50 having a water jacket 8 provided so as to separate the cylinder block outer wall 12 from each other is employed.

Further, as shown in FIG. 9, tightening boss portions 13 to 17 having tightening holes 13 a to 17 a to which head bolts (not shown) are tightened on the long-side cylinder block outer walls 11 and 11 of the cylinder block 50. Are formed at intervals (10 in FIG. 9). Of these tightening boss portions 13 to 17, two pairs of tightening boss portions 13 and 13 and 17 and 17 are respectively disposed at both ends of the long-side cylinder block outer walls 11 and 11 of the cylinder block 1 and 3 The pair of tightening boss portions 14 and 14, 15 and 15, and 16 and 16 are respectively disposed on both sides of each coupling portion of the adjacent cylinder bores 3 to 6.
When the cylinder head is assembled to the cylinder block 50, the cylinder head is placed in a state where a gasket is interposed on the upper surface of the cylinder block 50, and the head bolt is attached to the longitudinal side cylinder block outer wall 11 of the cylinder block 50. The cylinder head is assembled to the cylinder block 50 by tightening in the tightening holes 13a to 17a of the tightening boss portions 13 to 17 provided in the cylinder 11. FIG. 9 schematically shows the upper surface of the cylinder block, and illustration of the cylinder head, the head bolt, and the gasket is omitted.

  However, when the cylinder block 50 is tightened to the cylinder head with a predetermined tightening torque by a head bolt via a gasket, as indicated as a problem from the past, the cylinder bores 3 to 6 are in a deformed state. The deformation of the cylinder bores 3 and 6 located in the position is significantly deteriorated. As shown in FIGS. 10 and 11, when the cylinder block 50 is assembled to the cylinder head, the cylinder bore 3 positioned at the end in the longitudinal direction of the cylinder block 50 has a semicircular portion of the cylinder bore 3 as shown in FIG. The tightening force of the two head bolts inserted through the tightening holes 13a and 13a on both sides of the region (region surrounded by the dotted line in FIG. 10B) acts on this region. The cylinder bore 4 located in the middle has a clamping hole on both sides of the coupling portion for each semicircular area (area surrounded by a solid line in FIG. 10B) of the adjacent cylinder bores 3 and 4. The tightening force of the two head bolts inserted through 14a and 14a acts. Therefore, the tightening force acting on the cylinder bore 3 located at the end becomes larger than the tightening force acting on the cylinder bore 4 located in the middle, and the bore wall 3a of the cylinder bore 3 becomes the same as in FIG. As shown in FIG. 11 (b), it deforms into an elliptical shape when viewed from the top, and buckles when viewed from the side.

  When assembled in such a state, the deformation of the bore makes it difficult for the piston ring to follow the deformation of the bore during operation, and the lubricating oil enters the combustion chamber and burns, increasing the consumption of the lubricating oil. Cause a problem of blow-by gas.

Various proposals have been made to solve such problems, and Patent Document 1 discloses that in an open deck type cylinder block, cylinder bores positioned at both ends in the crankshaft direction are arranged in the direction of the crankshaft. It is disclosed that the thickness near the end facing the outer wall is made thicker than the thickness of the other part to prevent deformation of the cylinder bores located at both ends when the cylinder head is assembled to the cylinder block. Yes.
JP 10-47153 A

  As described above, in the invention of Patent Document 1, the cylinder bores located at both ends are made thicker in the vicinity of the end facing the cylinder block outer wall in the crankshaft direction than the other parts, and each cylinder bore is However, it is not possible to suppress the deformation of the cylinder bore located at both ends by simply changing the shape of the cylinder block, and by changing the shape of the cylinder block alone, it is positioned at both ends. It cannot be the fundamental solution to the deformation generation mechanism of the cylinder bore.

The present invention has been made in view of the above points, and when assembling an open deck type cylinder block to a cylinder head via a gasket, it is possible to suppress deformation of cylinder bores positioned at both ends in the longitudinal direction of the cylinder block. An object is to provide an open deck type cylinder block.

The present invention provides, as means for solving the above-mentioned problems, the invention of the open deck type cylinder block according to claim 1, in which each bore wall of each cylinder bore positioned at both longitudinal ends of the open deck type cylinder block is provided. Wall portions projecting from the outer wall surface of each bore wall toward the inner wall surface of the cylinder block outer wall are integrally formed at portions facing the inner wall surface of the cylinder block outer wall located on both longitudinal sides of the cylinder block. A gasket having a gasket bead formed and formed along each bore wall of each cylinder bore and an upper surface of each wall portion is provided .
The invention of the open deck type cylinder block described in claim 2 is the invention described in claim 1, wherein the wall portion is a bore wall of a virtual cylinder bore coupled to the cylinder block outer wall side of each cylinder bore. It is characterized by being formed in a shape that forms a part.
The invention of the open deck type cylinder block described in claim 3 is characterized in that, in the invention described in claim 1 or 2, the height of the wall portion is set substantially equal to the depth of the water jacket. To do.

Furthermore, as means for solving the above-mentioned problem, the invention of the open deck type cylinder block according to claim 4 is characterized in that the bore wall of each cylinder bore positioned at both ends in the longitudinal direction of the open deck type cylinder block is provided with the cylinder. A part of the bore wall of the virtual cylinder bore is joined to the inner wall surface of the cylinder block outer wall located on both sides in the longitudinal direction of the block, and the outer wall surface of each cylinder block is joined to the cylinder block outer wall of each cylinder bore. And a gasket having a gasket bead formed so as to be along the upper surface of each bore wall of each cylinder bore and the recess forming portion of the cylinder block outer wall. To do.

Therefore, in the invention of the open deck type cylinder block according to the first aspect, the cylinder block is provided on each bore wall of each cylinder bore located at both longitudinal ends of the open deck type cylinder block from the outer wall surface of each bore wall. Since the wall portions projecting toward the inner wall surface of the cylinder block outer wall located at both ends in the longitudinal direction are formed integrally with each other, the bore wall of the cylinder bore located at both ends provides the rigidity of the deformed portion assumed at the time of assembly. Be improved. In addition, since the gasket bead is formed along the bore wall of each cylinder bore and the upper surface of each wall portion, the gasket is interposed between the cylinder block and the cylinder head by a head bolt. When tightening, the tightening force of the head bolt around the cylinder bore located at both ends is transmitted to each wall portion through the gasket bead of the gasket, so the rigidity of the bore wall of the cylinder bore located at both ends is It works effectively to suppress the deformation.
In the invention of the open deck type cylinder block according to claim 2, the shape is such that each wall portion forms part of the bore wall of the virtual cylinder bore coupled to the cylinder block outer wall side of each cylinder bore located at both ends. Therefore, when the head bolts around the cylinder bores located at both ends are tightened, the tightening force is distributed to the cylinder bores at the both ends and each wall portion (virtual cylinder bore). The tightening force is prevented from acting only on the cylinder bores at both ends, and deformation of the cylinder bores located at both ends is suppressed.
In the invention of the open deck type cylinder block according to the third aspect, the rigidity of the bore wall of the cylinder bore located at both ends is further improved.

In the invention of the cylinder block according to claim 4 , a concave portion is formed on each outer wall surface of each cylinder block outer wall, and the inner wall surface of each cylinder block outer wall is coupled to each bore wall of each cylinder bore located at both ends, Since a part of the bore wall of the virtual cylinder bore is connected to the connecting part of each cylinder bore located at both ends with the cylinder block outer wall, the bore wall of the cylinder bore at both ends provides the rigidity of the deformed part assumed at the time of assembly. Be improved. In addition, since the gasket bead is formed along the upper surface of the recessed portion provided in each bore wall of each cylinder bore and the cylinder block outer wall, the gasket is interposed between the cylinder block and the cylinder head. When tightening with the head bolt in the mounted state, the tightening force of the head bolt around the cylinder bore located at both ends is particularly affected by the formation part of the recess provided on the outer wall of the cylinder block via the gasket bead of the gasket (bore of the virtual cylinder bore Therefore, the rigidity of the bore walls of the cylinder bores located at both ends effectively acts to suppress the deformation.

According to the present invention, when assembled to the cylinder head open deck type cylinder block via a gasket, providing both longitudinal ends deform the open deck type capable of suppressing the cylinder bore located in the cylinder block of the cylinder block be able to.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to FIGS. The same members and corresponding parts as in the conventional example will be described using the same reference numerals.
As shown in FIGS. 1 to 3, the cylinder block 1 according to the embodiment of the present invention includes a plurality of substantially linear (in the present embodiment, four in series) on the mating surface 7 with the cylinder head (not shown). The cylinder block 1 is configured as an open deck type cylinder block 1 having a water jacket 8 provided to open around the cylinder bores 3 to 6 arranged.

  As shown in FIGS. 1 and 2, the cylinder block 1 has four cylinder bores 3 to 6 arranged in series. These cylinder bores 3 to 6 are configured as # 1 cylinder 3, # 2 cylinder 4, # 3 cylinder 5, and # 4 cylinder 6 from the front end side toward the rear end side. Further, the cylinder block 1 includes a water jacket 8 that opens around each of the cylinder bores 3 to 6 on the mating surface 7 with the cylinder head. The water jacket 8 is formed so as to be spaced from the cylinder block outer wall 12 around each of the cylinder bores 3 to 8. The water jacket 8 is formed at an appropriate depth to improve the cooling efficiency of the engine. The cylinder block 1 is a siamese type cylinder block constructed by integrally connecting the cylinder bores 3 to 6 in series.

  As shown in FIG. 1, tightening boss portions 13 to 17 having fastening holes 13 a to 17 a to which head bolts (not shown) are fastened are spaced on the long-side cylinder block outer walls 11 and 11 of the cylinder block 1. In this embodiment, a plurality are formed (10 in this embodiment). Of these tightening boss portions 13 to 17, two pairs of tightening boss portions 13 and 13 and 17 and 17 are respectively disposed at both ends of the long-side cylinder block outer walls 11 and 11 of the cylinder block 1 and 3 The pair of tightening boss portions 14 and 14, 15 and 15, and 16 and 16 are respectively disposed on both sides of each coupling portion of the adjacent cylinder bores 3 to 6.

  Further, on the outer wall surfaces of the bore walls 3a and 6a of the cylinder bores 3 and 6 located at both ends in the longitudinal direction of the cylinder block 1, the portions facing the inner wall surfaces of the short cylinder block outer walls 10 and 10 of the cylinder block 1 Wall portions 20 and 20 projecting from the outer wall surfaces of the bore walls 3a and 6a toward the inner wall surfaces of the short cylinder block outer walls 10 and 10 are integrally coupled to each other. These wall portions 20 and 20 are formed in substantially the same shape as a part of the bore walls 3a and 6a of the cylinder bores 3 and 6, respectively. Moreover, the height of these wall parts 20 and 20 is set to be substantially the same as the depth of the water jacket 8.

Further, the form of connection between the outer wall surfaces of these wall portions 20 and 20 and the outer wall surfaces of the bore walls 3a and 6a of the cylinder bores 3 and 6 is the respective outer wall surfaces of the bore walls 4a and 5a of the adjacent cylinder bores 4 and 5. Is substantially the same as the bonding form in which is bound.
Further, the circumferential length (or central angle) of each wall portion 20, 20 is such that each wall portion 20, 20 is coupled to the outer wall surface of the bore walls 3a, 6a of the cylinder bores 3, 6 at both ends. The outer cylinder walls 10 and 10 of the short side and the bore walls 3a and 6a of the cylinder bores 3 and 6 are appropriately set so as to be positioned in the water jackets 8 and 8. In addition, each wall part 20 and 20 may have a form in which both end parts opposite to the connecting part with the bore walls 3a and 6a are integrally coupled to the short side cylinder block outer walls 10 and 10 of the cylinder block 1. .

  As described above, the wall portions 20 and 20 integrally coupled to the bore walls 3a and 6a of the cylinder bores 3 and 6 located at both ends are substantially the same shape as a part of the bore walls 3a and 6a of the cylinder bores 3 and 6. In other words, in order to be configured as a pseudo cylinder bore (virtual cylinder bore), the cylinder bores 3 and 6 positioned at both ends have an environment in which the cylinder bore is coupled to the short side cylinder block outer walls 10 and 10 side. become.

Next, the gasket 2 according to the embodiment of the present invention is used for the cylinder block 1 according to the embodiment of the present invention described above, and is formed in a plate shape made of a single plate or a laminated plate, Although not shown in FIG. 3, each cylinder bore 3 to 6, the water jacket 8, and an oil passage (not shown) for communicating the cylinder block 1 and the cylinder head are provided with a space for appropriately avoiding the above. The gasket beads are formed at appropriate positions in order to maintain their sealing properties.
Further, as shown in FIG. 3, the gasket 2 has a plurality of substantially cylindrical shapes (four in this embodiment) that are formed along the upper surfaces of the bore walls 3a to 6a of the cylinder bores 3 to 6. ) And arc-shaped gasket beads 24, 24 formed along the upper surfaces of the wall portions 20, 20 and joined to the gasket beads 23, 23 at both ends.

  Then, as shown in FIGS. 4 and 5, with the cylinder block 1 and the cylinder head interposed with the gasket 2, the head bolts are tightened into the tightening holes 13a and 13a on both sides of the cylinder bore 3 at the end, The tightening force acts on the upper surface of the bore wall 3a and the upper surface of the wall portion 20 of the cylinder bore 3 in the region surrounded by the dotted line in FIG. 4 (b) via the gasket beads 23, 24 of the gasket 2. The tightening force is distributed to the cylinder bore 3 and the wall portion 20. Thus, unlike the conventional case, the tightening force of the head bolt does not act only on the cylinder bore 3 at the end, and the deformation of the bore wall 3a of the cylinder bore 3 at the end, that is, the elliptical deformation in the top view (Refer to FIG. 10B) and deformation due to buckling in a side view (see FIG. 11B) are suppressed.

  Next, when the cylinder block 1 is assembled to the cylinder head via the gasket 2, the amount of deformation of the cylinder bore 3 positioned at the end of the conventional structure and the amount of deformation of the cylinder bore 3 positioned at the end of the structure of the present invention are as follows. And FIG. 6 and FIG. 7 will be used to explain the results of comparative analysis of the above from the viewpoint of roundness of the cylinder bore 3 by the finite element method (FEM).

  FIG. 6 is a graph showing the roundness (0.A value: overall value) on a plane at each distance from the upper surface of the cylinder bore 3, and the structure of the present invention has a structure of the cylinder bore 3 as compared with the conventional structure. It can be seen that the roundness is improved by about 50%.

  FIG. 7 is a graph showing the roundness (fourth-order deformation value) on the plane at each distance from the upper surface of the cylinder bore. The structure of the present invention has a perfect circle of the cylinder bore 3 as compared with the conventional structure. It can be seen that the degree is improved by about 25%.

  As described above, according to the embodiment of the present invention, the outer wall surfaces of the bore walls 3a and 6a of the cylinder bores 3 and 6 positioned at both ends of the open deck type cylinder block 1 are arranged on the short side of the cylinder block 1. A wall having substantially the same shape as part of the bore walls 3a and 6a of the cylinder bores 3 and 6 so that a part of the bore wall of the virtual cylinder bore is formed in a portion facing the inner wall surface of the cylinder block outer walls 10 and 10. The parts 20 and 20 are integrally coupled so as to protrude toward the short cylinder block outer wall 10 and 10 side, respectively. Further, the gasket 2 is formed with gasket beads 23 and 24 along at least the bore walls 3a and 6a of the cylinder bores 3 to 6 and the upper surfaces of the wall portions 20 and 20, respectively.

Thereby, the cylinder bores 3 and 6 located at both ends of the cylinder block 1 are formed by integrally connecting the wall portions 20 and 20 having a shape that forms part of the bore wall of the virtual cylinder bore, The cylinder bores 4 and 5 located in the middle have substantially the same environment, and the gasket 2 is formed with gasket beads 24 and 24 along the upper surfaces of the wall portions 20 and 20, respectively. When the head bolts on both sides of 3 and 6 are tightened, the tightening force is not concentrated only on the cylinder bores 3 and 6 on both ends, but is also distributed on the wall portions 20 and 20, so that the cylinder bores 3 and 6 on both ends are deformed. The amount can be suppressed.
And since it became possible to suppress the deformation | transformation of the cylinder bores 3 and 6 located in the both ends when the cylinder block 1 is assembled | attached to a cylinder head which was considered as a problem conventionally, lubricating oil penetrate | invades into a combustion chamber at the time of an operation | movement. This makes it possible to reduce the consumption of lubricating oil, and to suppress the generation of blow-by gas.

Next, another embodiment of the open deck type cylinder block 1 will be described with reference to FIG.
The cylinder block 1a forms curved wall portions 20 and 20 by curving the substantially central portions of the short side cylinder block outer walls 10 and 10 inwardly, and the outer wall surfaces of the wall portions 20 and 20 are formed. The cylinder bores 3 and 6 located at both ends are coupled to the outer wall surfaces of the bore walls 3a and 6a.
More specifically, the wall portions 20 and 20 of the cylinder block 1a are formed so that the shape thereof is substantially the same as a part of the bore walls 3a and 6a of the cylinder bores 3 and 6, that is, located at both ends. An arcuate concave portion 21 is formed at a substantially central portion of the short cylinder block outer walls 10 and 10 so that a part of the bore wall of the virtual cylinder bore is connected to the connecting portion of the cylinder bores 3 and 6 with the bore walls 3a and 6a. , 21 are formed.

  Moreover, the gasket 2 used for the cylinder block 1a of other embodiment is the same as the gasket 2 used for the cylinder block 1 shown in FIG. 1, and as shown in FIG. 3, the bore wall of each cylinder bore 3-6. A plurality of (four in the present embodiment) gasket beads 23 formed along the upper surfaces of 3a to 6a and coupled to each other in a substantially cylindrical shape, and respective wall portions (formation portions of the recesses 21, 21) 20, 20 is a structure having arcuate gasket beads 24, 24 coupled to gasket beads 23, 23 at both ends, formed along the upper surface of 20.

  With this configuration, the cylinder bores 3 and 6 positioned at both ends of the cylinder block 1a have substantially the same rigidity as the cylinder bores 3 and 6 positioned at both ends of the cylinder block 1 shown in FIG. When the block 1a is assembled to the cylinder head, the deformation of the cylinder bores 3 and 6 located at both ends can be suppressed, the consumption amount of lubricating oil can be reduced, and the generation of blow-by gas can also be suppressed.

  Here, when each wall part 20 and 20 is comprised like other embodiment mentioned above, it is a water jacket between the cylinder bores 3 and 6 of both ends, and the short side cylinder block outer wall 10 and 10 of the cylinder block 1a. 8 and 8 are not configured. However, since it is the cylinder bores 4 and 5 located in the middle that reach the maximum temperature in the problem of cooling performance, the cylinder bores 3 and 6 located at both ends, and the short side cylinder block outer walls 10 and 10 of the cylinder block 1a The presence or absence of the water jackets 8 and 8 in between is not so much of a problem. If necessary, a cooling water passage for communicating the water jackets 8 and 8 located on both sides of the cylinder bores 3 to 6 may be provided in the upper part of the cylinder block 1a.

  In the embodiment of the present invention, in order to make the cylinder bores 3, 6 located at both ends substantially the same environment as the intermediate cylinder bores 4, 5, the wall portions 20, 20 are formed in the bore walls 3 a of the cylinder bores 3, 6. However, the shape of each of the wall portions 20 and 20 is not limited to this shape as long as the shape has rigidity equivalent to that of each of the wall portions 20 and 20. .

FIG. 1 schematically shows the upper surface of an open deck type cylinder block according to an embodiment of the present invention. FIG. 2 is a perspective view of an end portion of the open deck type cylinder block according to the embodiment of the present invention as viewed obliquely from above. FIG. 3 is a top view showing main gasket beads of the gasket according to the embodiment of the present invention. 4A and 4B are top views showing how the cylinder bore is deformed in the cylinder block of the present invention, wherein FIG. 4A shows before tightening and FIG. 4B shows after tightening. FIG. 5 is a side view showing how the cylinder bore is deformed in the cylinder block of the present invention, where (a) shows before tightening and (b) shows after tightening. FIG. 6 is a diagram showing the result of comparative analysis of the roundness (OA value) of the cylinder bore located at the end by the finite element method between the conventional structure and the invention structure. FIG. 7 is a diagram showing the result of comparative analysis of the roundness (fourth-order deformation value) of the cylinder bore located at the end by the finite element method between the conventional structure and the invention structure. FIG. 8 schematically shows the upper surface of another embodiment of the cylinder block. FIG. 9 schematically illustrates the upper surface of a conventional open deck type cylinder block. 10A and 10B are top views showing how cylinder bores are deformed in a conventional cylinder block, wherein FIG. 10A shows before tightening and FIG. 10B shows after tightening. FIG. 11 is a side view showing how the cylinder bore is deformed in a conventional cylinder block, where (a) shows before tightening and (b) shows after tightening.

Explanation of symbols

1, 1a Open deck type cylinder block, 2 Gasket, 3-6 Cylinder bore, 3a-6a Bore wall, 10 Short side cylinder block outer wall, 11 Long side cylinder block outer wall, 12 Cylinder block outer wall, 13a-17a Tightening hole , 20 Wall, 21 Recess, 23, 24 Gasket beads

Claims (4)

The outer wall surface of each bore wall is located at the part of each bore wall of each cylinder bore located at both ends in the longitudinal direction of the open deck type cylinder block that faces the inner wall surface of the cylinder block outer wall located at both sides in the longitudinal direction of the cylinder block. Wall portions projecting from the cylinder block outer wall toward the inner wall surface of the cylinder block are integrally formed ,
An open deck type cylinder block comprising a gasket having a gasket bead formed along each bore wall of each cylinder bore and an upper surface of each wall portion .   2. The open deck type of claim 1, wherein the wall portion is formed in a shape so as to form a part of a bore wall of a virtual cylinder bore coupled to the cylinder block outer wall side of each cylinder bore. Cylinder block.   3. The open deck type cylinder block according to claim 1, wherein the height of the wall portion is set to be substantially the same as the depth of the water jacket. The bore wall of each cylinder bore located at both ends in the longitudinal direction of the open deck type cylinder block is integrally coupled to the inner wall surface of the cylinder block outer wall located at both sides in the longitudinal direction of the cylinder block, and the outer wall surface of each cylinder block outer wall In addition, a concave portion is formed such that a part of the bore wall of the virtual cylinder bore is connected to the coupling portion of each cylinder bore with the cylinder block outer wall ,
An open deck type cylinder block comprising a gasket having a gasket bead formed so as to be along the upper surface of each bore wall of each cylinder bore and the concave portion of the cylinder block outer wall .

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