Cylinder block of the engine

Abstract

To provide a cylinder block of an engine capable of suppressing noise caused by deformation of the cylinder block during an operation of the engine, while reducing a weight of the cylinder block.SOLUTION: An outer surface 8A of a skirt portion 8 is formed with: a first reinforcement rib 11 and a second reinforcement rib 12 which are disposed at a central portion in a cylinder row direction of a skirt portion 8 while crossing in a X-shape and connected to a first end wall portion 5 and a second end wall portion 6; and a third reinforcement rib 13 and a fourth reinforcement rib 14 which are disposed at a lower part of the first reinforcement rib 11 and the second reinforcement rib 12 in a V-shape and connected to the first reinforcement rib 11, the second reinforcement rib 12, and a central portion in a cylinder row direction of an oil pan mounting flange portion 7. The third reinforcement rib 13 and the fourth reinforcement rib 14 are connected to the central portion in the cylinder row direction of the oil pan mounting flange portion 7 at a bottom portion of the V-shape, and upper end portions of the V-shape are respectively connected to the first reinforcement rib 11 and the second reinforcement rib 12.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a cylinder block of an engine.

Background Art

[0002] As a conventional cylinder block of an engine, there is a deep skirt type cylinder block in which a skirt portion is formed so as to extend to a lower side surface of a crankshaft. As this type of conventional cylinder block, the one described in Patent Document 1 is known. In the cylinder block described in Patent Document 1, a second reinforcing rib and a third reinforcing rib are arranged in an X shape on a front side surface of the cylinder block. Thereby, it is possible to suppress the skirt portion from vibrating so as to be twisted around the crankshaft by the deforming crankshaft in the cylinder block described in Patent Document 1.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the technique described in Patent Document 1, there is room for consideration because a triangular region below the X-shaped rib in the skirt portion may be deformed by a load from the crankshaft and noise may be generated.

[0005] The present invention has been made paying attention to the above circumstances, and an object of the present invention is to provide a cylinder block of an engine that can suppress noise generated due to deformation of the cylinder block during operation of the engine while achieving weight reduction of the cylinder block.

Means for Solving the Problems

[0006] The present invention relates to a cylinder block of an engine having a cylinder portion in which a plurality of cylinders are arranged in series, a skirt portion provided at a lower portion of the cylinder portion so as to surround a crankshaft from the side, and having an oil pan mounting flange portion at its lower end, a first end wall portion provided at one end portion of the cylinder portion and the skirt portion in the cylinder row direction, and a second end wall portion provided at the other end portion of the cylinder portion and the skirt portion in the cylinder row direction. In the cylinder block, on the outer surface of the skirt portion, a first reinforcing rib and a second reinforcing rib are arranged to intersect in an X shape at the central portion of the skirt portion in the cylinder row direction and are connected to the first end wall portion and the second end wall portion, and a third reinforcing rib and a fourth reinforcing rib are arranged in a V shape below the first reinforcing rib and the second reinforcing rib and are connected to the first reinforcing rib, the second reinforcing rib, and the central portion of the oil pan mounting flange portion in the cylinder row direction. The third reinforcing rib and the fourth reinforcing rib are characterized in that the bottom of the V shape is connected to the central portion of the oil pan mounting flange portion in the cylinder row direction, and the upper end portions of the V shape are respectively connected to the first reinforcing rib and the second reinforcing rib.

Effects of the Invention

[0007] According to the present invention as described above, it is possible to provide a cylinder block of an engine that can suppress noise generated due to deformation of the cylinder block during operation of the engine while reducing the weight of the cylinder block.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

[0009] In a cylinder block of an engine according to an embodiment of the present invention, a cylinder block includes a cylinder portion in which a plurality of cylinders are arranged in series, a skirt portion provided at a lower portion of the cylinder portion so as to surround a crankshaft from the side, and having an oil pan mounting flange portion at its lower end, a first end wall portion provided at one end of the cylinder block in the cylinder row direction of the cylinder portion and the skirt portion, and a second end wall portion provided at the other end of the cylinder block in the cylinder row direction of the cylinder portion and the skirt portion. In the cylinder block of the engine, on the outer surface of the skirt portion, first reinforcing ribs and second reinforcing ribs are arranged to intersect in an X shape at the central portion of the skirt portion in the cylinder row direction and are connected to the first end wall portion and the second end wall portion, and third reinforcing ribs and fourth reinforcing ribs are arranged in a V shape below the first reinforcing ribs and the second reinforcing ribs and are connected to the first reinforcing ribs, the second reinforcing ribs, and the central portion of the oil pan mounting flange portion in the cylinder row direction. The third reinforcing ribs and the fourth reinforcing ribs are characterized in that the bottom of the V shape is connected to the central portion of the oil pan mounting flange portion in the cylinder row direction, and the upper ends of the V shape are respectively connected to the first reinforcing rib and the second reinforcing rib.

[0010] Thereby, the cylinder block of the engine according to an embodiment of the present invention can suppress noise generated due to deformation of the cylinder block during operation of the engine while reducing the weight of the cylinder block. **EXAMPLE**

[0011] Hereinafter, a cylinder block of an engine according to an embodiment of the present invention will be described with reference to the drawings. FIGS. 1 to 5 are views showing a cylinder block of an engine according to an embodiment of the present invention. In FIGS. 1 to 5, the front, rear, left, and right designations represent the front, rear, left, and right of a vehicle on which the engine is mounted.

[0012] First, the configuration will be described. In FIGS. 1 and 2, a crankshaft 9 is provided in a cylinder block 1 of an engine, and the crankshaft 9 extends in the front-rear direction. In the cylinder block 1, a plurality (three in this embodiment) of cylinders 3 arranged in series along the axis C (see FIG. 4) of the crankshaft 9 are formed, and each cylinder 3 extends in the vertical direction. The engine according to this embodiment is an FR (front engine - rear drive) type vertical engine.

[0013] The cylinder block 1 includes a cylinder portion 2 in which a plurality of cylinders 3 are arranged in series, and a skirt portion 8 provided at the lower part of the cylinder portion 2 so as to surround the crankshaft 9 from the side. An oil pan mounting flange portion 7 is provided at the lower end of the skirt portion 8.

[0014] A cylinder head (not shown) is provided above the cylinder block 1. The cylinder head has an intake port for taking in air, an exhaust port for discharging exhaust gas, intake valves, exhaust valves, etc. The intake port opens in the right side wall of the cylinder head, and the exhaust port opens in the left side wall of the cylinder head.

[0015] A cylinder head cover (not shown) is installed above the cylinder head. An oil pan (not shown) is installed below the cylinder block 1, and oil for lubricating the engine is stored in the oil pan.

[0016] An oil pan is connected to the oil pan mounting flange portion 7 of the skirt portion 8 by bolts. The oil pan mounting flange portion 7 is formed thick so as to have sufficient rigidity for connection with the oil pan. A crank chamber is formed inside the skirt portion 8.

[0017] An upper deck 4 connected to the cylinder head is provided on the upper surface of the cylinder portion 2. The upper deck 4 has sufficient rigidity for connection with the cylinder head.

[0018] A first end wall portion 5 is provided at one end (front end) in the cylinder row direction of the cylinder portion 2 and the skirt portion 8. A second end wall portion 6 is provided at the other end (rear end) in the cylinder row direction of the cylinder portion 2 and the skirt portion 8.

[0019] The first end wall portion 5 constitutes the outer wall surface at the front end of the cylinder block 1 and protrudes in the left - right direction more than the cylinder portion 2 and the skirt portion 8. An auxiliary machine such as a generator (not shown) is connected to the first end wall portion 5 by bolts.

[0020] The second end wall portion 6 constitutes the outer wall surface at the rear end of the cylinder block 1 and protrudes in the left - right direction more than the cylinder portion 2 and the skirt portion 8. A transmission (not shown) is connected to the second end wall portion 6 by bolts.

[0021] In this way, since the first end wall portion 5 and the second end wall portion 6 constitute a flange portion connected to the auxiliary machine or the transmission, they have sufficient rigidity for connection to the auxiliary machine or the transmission.

[0022] In this embodiment, the engine is mounted on the vehicle such that the cylinder axes 3C (see FIG. 2), which are the central axes of the plurality of cylinders 3 of the cylinder block 1, are substantially parallel to the up - down direction of the vehicle. However, the engine may be mounted on the vehicle such that the cylinder axis 3C is inclined in either the left or right direction.

[0023] Here, during the operation of the engine, as shown in FIG. 3, the deforming crankshaft 9 deforms and vibrates in a direction to twist the skirt portion 8 in the direction of arrow Y, generating noise. Therefore, in this embodiment, by forming an X - shaped rib 17 on the outer surface 8A of the skirt portion 8, the deformation and vibration of the skirt portion 8 are suppressed.

[0024] In FIGS. 1 and 2, an X-shaped rib 17 is formed on the outer surface 8A on the left side of the skirt portion 8. The X-shaped rib 17 is composed of a first reinforcing rib 11 and a second reinforcing rib 12, and protrudes outward (leftward) from the outer surface 8A on the left side of the skirt portion 8. The first reinforcing rib 11 and the second reinforcing rib 12 are arranged to intersect in an X shape at the central portion in the cylinder row direction of the skirt portion 8, and are connected to the first end wall portion 5 and the second end wall portion 6.

[0025] Specifically, the first reinforcing rib 11 extends obliquely upward from the first end wall portion 5 toward the second end wall portion 6. Also, the second reinforcing rib 12 extends obliquely downward from the first end wall portion 5 toward the second end wall portion 6. The first reinforcing rib 11 and the second reinforcing rib 12 intersect at the intersection point 17A. The central portion in the cylinder row direction is a region having a predetermined length near the central portion in the direction (front-rear direction) of the cylinder row. Therefore, the central portion in the cylinder row direction of the skirt portion 8 where the intersection point 17A of the first reinforcing rib 11 and the second reinforcing rib 12 is arranged is a region having a predetermined length near the central portion in the direction (front-rear direction) of the cylinder row of the skirt portion 8.

[0026] Here, even when the overall deformation and vibration of the outer surface 8A of the skirt portion 8 are suppressed by the X-shaped rib 17, the triangular region S below the X-shaped rib 17 on the outer surface 8A may be displaced in the radial direction of the crankshaft 9 (the direction toward the front or the back in FIG. 2) to generate noise. The region S is a partial region of the outer surface 8A, and is a region surrounded by the first reinforcing rib 11, the second reinforcing rib 12, and the oil pan mounting flange portion 7. In order to suppress the noise generated due to the deformation of the region S of the cylinder block during the operation of the engine, it is preferable to increase the rigidity of the region S. Also, it is preferable to increase the rigidity of the region S while reducing the weight of the cylinder block 1. Therefore, in the present embodiment, by forming a V-shaped rib 18 described later on the outer surface 8A of the skirt portion 8, the vibration of the skirt portion 8 is suppressed.

[0027] In this embodiment, below the first reinforcing rib 11 and the second reinforcing rib 12 on the outer surface 8A on the left side of the skirt portion 8, a V-shaped rib 18 is formed. The V-shaped rib 18 is composed of a third reinforcing rib 13 and a fourth reinforcing rib 14 arranged in a V shape, and protrudes outward (leftward) from the outer surface 8A on the left side of the skirt portion 8. The third reinforcing rib 13 and the fourth reinforcing rib 14 are connected to the first reinforcing rib 11 and the second reinforcing rib 12 and the central portion in the cylinder row direction of the oil pan mounting flange portion 7.

[0028] Specifically, the upper end portion of the third reinforcing rib 13 is connected to a portion in front of and below the intersection 17A in the second reinforcing rib 12. The fourth reinforcing rib 14 is connected to a portion behind and below the intersection 17A in the first reinforcing rib 11. Further, the lower end portions of the third reinforcing rib 13 and the fourth reinforcing rib 14 are connected to the central portion in the cylinder row direction of the oil pan mounting flange portion 7.

[0029] In this way, in the third reinforcing rib 13 and the fourth reinforcing rib 14, the intersection 18A that is the bottom of the V shape is connected to the central portion in the cylinder row direction of the oil pan mounting flange portion 7. Also, in the third reinforcing rib 13 and the fourth reinforcing rib 14, the upper end portions of the V shape are respectively connected to the first reinforcing rib 11 and the second reinforcing rib 12.

[0030] In FIG. 3, the skirt portion 8 has a plurality (two in this embodiment) of partition walls 15, 16 that support the crankshaft 9 between a plurality of cylinders 3. The partition wall 15 is disposed between the central cylinder 3 and the front-end cylinder 3 and extends in the left-right direction. The partition wall 16 is disposed between the central cylinder 3 and the rear-end cylinder 3 and extends in the left-right direction. The partition walls 15, 16 are connected to the inner surface of the skirt portion 8. Therefore, the portions of the skirt portion 8 that are connected to the partition walls 15, 16 have higher rigidity compared to other portions.

[0031] In FIGS. 1 and 2, the upper ends of the third reinforcing rib 13 and the fourth reinforcing rib 14 are located at the outer parts of the partitions 15 and 16 (see FIG. 3) on the outer surface 8A of the skirt portion 8, and are connected to the first reinforcing rib 11 or the second reinforcing rib 12. Specifically, the upper end of the third reinforcing rib 13 is connected to the first reinforcing rib 11 at the outer part (left side) of the partition 15 on the outer surface 8A of the skirt portion 8. Also, the upper end of the fourth reinforcing rib 14 is connected to the second reinforcing rib 12 at the outer part (left side) of the partition 16 on the outer surface 8A of the skirt portion 8. Therefore, the upper end of the third reinforcing rib 13 and the first reinforcing rib 11 are connected at the portion where the rigidity is enhanced by the partition 15 on the outer surface 8A of the skirt portion 8. Also, the upper end of the fourth reinforcing rib 14 and the second reinforcing rib 12 are connected at the portion where the rigidity is enhanced by the partition 16 on the outer surface 8A of the skirt portion 8.

[0032] Note that bearing caps (not shown) are mounted from below at the central portions in the left - right direction of the first end wall portion 5, the second end wall portion 6, the partitions 15, and 16. The bearing caps hold a bearing (not shown) that rotatably supports the crankshaft 9. Therefore, the first end wall portion 5, the second end wall portion 6, the partitions 15, and 16 support the crankshaft 9 via the bearing.

[0033] In FIG. 2, the third reinforcing rib 13 and the fourth reinforcing rib 14 are inclined such that the inclination angles A and B with respect to the virtual line L parallel to the cylinder axis 3C passing through the intersection point 18A of the third reinforcing rib 13 and the fourth reinforcing rib 14 are different from each other. Specifically, the inclination angle B of the fourth reinforcing rib 14 with respect to the virtual line L is set larger than the inclination angle A of the third reinforcing rib 13 with respect to the virtual line L.

[0034] Also, the third reinforcing rib 13 is connected to the first reinforcing rib 11, and the fourth reinforcing rib 14 is connected to the second reinforcing rib 12. And the second reinforcing rib 12 is bent so as to extend parallel to the oil pan mounting flange portion 7 from the bent portion 12B located closer to the end in the cylinder row direction than the connecting portion 12A with the fourth reinforcing rib 14.

[0035] As described above, in this embodiment, on the outer surface 8A of the skirt portion 8, the first reinforcing ribs 11 and 12 that are arranged to intersect in an X shape at the central portion of the skirt portion 8 in the cylinder row direction and are connected to the first end wall portion 5 and the second end wall portion 6, and the first reinforcing ribs 11 and 12 are arranged in a V shape below, and the third reinforcing ribs 13 and 14 that are connected to the first reinforcing ribs 11 and 12 and the central portion of the oil pan mounting flange portion 7 in the cylinder row direction are formed. And, the third reinforcing ribs 13 and 14 are such that the bottom of the V shape is connected to the central portion of the oil pan mounting flange portion 7 in the cylinder row direction, and the upper end portions of the V shape are respectively connected to the first reinforcing rib 11 and the second reinforcing rib 12.

[0036] Thereby, during the operation of the engine, when the deforming crankshaft 9 vibrates the skirt portion 8 so as to twist it in the direction of arrow Y (see FIG. 3), it is possible to suppress the skirt portion 8 from being deformed so as to twist around the crankshaft 9 by the first reinforcing rib 11 and the second reinforcing rib 12 that intersect in an X shape and are arranged on the skirt portion 8.

[0037] Also, in this embodiment, since the third reinforcing ribs 13 and 14 arranged in a V shape are arranged on the skirt portion 8 such that the bottom of the V shape is connected to the central portion of the oil pan mounting flange portion 7 in the cylinder row direction, and the upper end portions of the V shape are respectively connected to the first reinforcing rib 11 and the second reinforcing rib 12, the rigidity of the triangular region S surrounded by the first reinforcing rib 11, the second reinforcing rib 12, and the oil pan mounting flange portion 7 can be improved by the third reinforcing ribs 13 and 14, and it is possible to suppress the lower portion of this region S from vibrating so as to bulge outward or dent inward. Therefore, it is possible to suppress the vibration noise generated from the cylinder block 1.

[0038] In particular, it is possible to prevent an increase in vibration noise caused by the frequency of the combustion pressure vibration generated in the combustion chamber of the engine and the exciting force accompanying its rotation resonating with the natural vibration frequency of the cylinder block 1, and it is possible to effectively reduce the noise radiated from this cylinder block 1 to the outside.

[0039] In addition, in the configuration where the two third reinforcing ribs 13 and fourth reinforcing ribs 14 are arranged in a V shape on the skirt portion 8, compared with the configuration where a large number of reinforcing ribs are arranged in a lattice pattern on the skirt portion 8, the number of reinforcing ribs can be reduced, and the structure can be simplified. Therefore, the weight of the cylinder block 1 can be reduced.

[0040] As a result, while reducing the weight of the cylinder block 1, it is possible to suppress the noise generated due to the deformation of the cylinder block 1 during the operation of the engine.

[0041] Note that the third reinforcing rib 13 and the fourth reinforcing rib 14 that constitute the V-shaped rib 18 are inclined with respect to the cylinder axis 3C and have a short length. Therefore, when the cylinder block 1 is created by casting, the molten metal can be evenly distributed to the portions of the third reinforcing rib 13 and the fourth reinforcing rib 14 of the mold, and the productivity can be improved.

[0042] In addition, in the present embodiment, the skirt portion 8 has a plurality of partitions 15 and 16 that support the crankshaft 9 between the plurality of cylinders 3. The upper ends of the third reinforcing rib 13 and the fourth reinforcing rib 14 are connected to the first reinforcing rib 11 or the second reinforcing rib 12 at the outer portions of the partitions 15 and 16 on the outer surface 8A of the skirt portion 8.

[0043] Thereby, since the upper ends of the third reinforcing rib 13 and the fourth reinforcing rib 14 are connected to the first reinforcing rib 11 or the second reinforcing rib 12 on the outer side of the partitions 15 and 16 arranged between the three cylinders 3, the third reinforcing rib 13 and the fourth reinforcing rib 14 can be suppressed from vibrating in the direction intersecting the crankshaft 9.

[0044] In addition, in the present embodiment, the third reinforcing rib 13 and the fourth reinforcing rib 14 are inclined so that the inclination angles with respect to the virtual line L parallel to the cylinder axis passing through the intersection of the third reinforcing rib 13 and the fourth reinforcing rib 14 are different from each other.

[0045] As a result, as shown in FIG. 5, even when the maximum deformation part 7A of the oil pan mounting flange part 7 is located at a position deviated to one side (front) from the center part in the cylinder row direction of the skirt part 8, the intersection point 18A at the bottom of the V shape of the V-shaped rib 18 can be arranged close to the maximum deformation part 7A, and the vibration of the maximum deformation part 7A of the oil pan mounting flange part 7 can be suppressed.

[0046] On the other hand, the cylinder block 50 according to the comparative example shown in FIG. 6 includes a cylinder part 52, a first end wall part 55, a second end wall part 56, an oil pan mounting flange part 57, a skirt part 58, a first reinforcing rib 53, and a second reinforcing rib 54, which are the same as the cylinder part 2, the first end wall part 5, the second end wall part 6, the oil pan mounting flange part 7, the skirt part 8, the first reinforcing rib 11, and the second reinforcing rib 12 in the cylinder block 1 according to the present embodiment, but does not include the V-shaped rib 18. For this reason, the vibration of the maximum deformation part 57A of the oil pan mounting flange part 57 cannot be suppressed.

[0047] Further, in the present embodiment, the inclination angle of the fourth reinforcing rib 14 with respect to the virtual line L is set larger than the inclination angle of the third reinforcing rib 13 with respect to the virtual line L. The third reinforcing rib 13 is connected to the first reinforcing rib 11, and the fourth reinforcing rib 14 is connected to the second reinforcing rib 12. The second reinforcing rib 12 is bent so as to extend in parallel with the oil pan mounting flange part 7 from a bent part 12B located closer to the end in the cylinder row direction than the connecting part 12A with the fourth reinforcing rib 14.

[0048] As a result, by bending the second reinforcing rib 12 connected to the fourth reinforcing rib 14 having a larger inclination than the third reinforcing rib 13 at the bent part 12B, the second reinforcing rib 12 can be arranged so as to be within the region of the central part in the vertical direction of the skirt part 8, and the vibration of the skirt part 8 can be suppressed.

[0049] Although embodiments of the present invention have been disclosed, it is obvious that those skilled in the art can make changes without departing from the scope of the present invention. It is intended that all such modifications and equivalents be included in the following claims.

Description of Reference Numerals

[0050] 1... Cylinder block, 2... Cylinder part, 3... Cylinder, 3C... Cylinder axis, 5... First end wall part, 6... Second end wall part, 7... Oil pan mounting flange part, 8... Skirt part, 8A... Outer surface, 9... Crankshaft, 11... First reinforcing rib, 12... Second reinforcing rib, 12A... Connecting part, 12B... Bent part, 13... Third reinforcing rib, 14... Fourth reinforcing rib, 15, 16... Partition wall, 17A... Intersection point, A, B... Inclination angle, L... Virtual line

Claims

1. A cylinder block including a cylinder section in which a plurality of cylinders are arranged in series, a skirt section provided at a lower portion of the cylinder section so as to surround a crankshaft from the side and having an oil pan mounting flange section at its lower end, a first end wall section provided at one end of the cylinder section and the skirt section in the cylinder row direction, a second end wall section provided at the other end of the cylinder section and the skirt section in the cylinder row direction, in a cylinder block of an engine, on an outer surface of the skirt section, a first reinforcing rib and a second reinforcing rib that are arranged to intersect in an X shape at a central portion of the skirt section in the cylinder row direction and are connected to the first end wall section and the second end wall section, a third reinforcing rib and a fourth reinforcing rib that are arranged in a V shape below the first reinforcing rib and the second reinforcing rib and are connected to the first reinforcing rib, the second reinforcing rib, and a central portion of the oil pan mounting flange section in the cylinder row direction are formed, the third reinforcing rib and the fourth reinforcing rib are characterized in that a bottom portion of the V shape is connected to a central portion of the oil pan mounting flange section in the cylinder row direction, and upper end portions of the V shape are connected to the first reinforcing rib and the second reinforcing rib, respectively, in a cylinder block of an engine.

2. the skirt section has a plurality of partition walls that support the crankshaft between the plurality of cylinders, the upper end of the third reinforcing rib and the upper end of the fourth reinforcing rib are connected to the first reinforcing rib or the second reinforcing rib at a portion outside the partition wall on the outer surface of the skirt section, according to claim 1, in a cylinder block of an engine.

3. the third reinforcing rib and the fourth reinforcing rib are inclined such that inclination angles with respect to a virtual line parallel to the cylinder axis passing through an intersection point of the third reinforcing rib and the fourth reinforcing rib are different from each other, according to claim 1, in a cylinder block of an engine.

4. the inclination angle of the fourth reinforcing rib with respect to the virtual line is set to be larger than the inclination angle of the third reinforcing rib with respect to the virtual line, the third reinforcing rib is connected to the first reinforcing rib, the fourth reinforcing rib is connected to the second reinforcing rib, the second reinforcing rib is bent so as to extend parallel to the oil pan mounting flange section from a bent portion that is closer to an end in the cylinder row direction than a connecting portion with the fourth reinforcing rib, according to claim 3, in a cylinder block of an engine.

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