JP2019138286A - Internal combustion engine - Google Patents

Abstract

To inhibit oil discharged from an oil discharge hole of a cylinder block from being rolled up or scattered by swirl wind caused by rotation of a crank shaft.SOLUTION: A first shield wall 72 protrudes upward from an upper surface of a balancer housing 70 supporting a balancer device 60 in an oil pan 40. A second shield wall 74 protrudes from an inner surface of the oil pan 40 to the side of the first shield wall 72. The first shield wall 72 and the second shield wall 74 are provided so as to enclose an opening of an oil discharge hole 24 on a lower surface of a cylinder block.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an internal combustion engine.

  In the internal combustion engine disclosed in Patent Document 1, an oil pan is disposed below the cylinder block. The cylinder block has an oil discharge hole for guiding oil lubricated to various parts of the internal combustion engine to the inside of the oil pan. The oil discharge hole is opened on the lower surface of the cylinder block. From this opening, oil flows down into the oil pan under its own weight.

JP 2010-59816 A

  Inside the oil pan of the internal combustion engine, an upward flow can be generated by the swirling flow of air accompanying the rotation of the crankshaft. This upward flow of air pushes back or scatters the oil discharged from the oil discharge hole of the cylinder block. For this reason, the oil may not easily reach the bottom surface of the oil pan that should return.

  An internal combustion engine for solving the above problems is an internal combustion engine in which an oil pan for storing oil is fixed below a cylinder block, and a balancer device is disposed inside the oil pan. The cylinder block has an oil discharge hole that opens in a lower surface of the cylinder block, and a balancer housing that supports the balancer device inside the oil pan is fixed to the lower surface of the cylinder block. A first shielding wall protrudes upward from the outer surface of the balancer housing, and a second shielding wall protrudes from the inner surface of the oil pan toward the first shielding wall, When viewed from the lower surface side of the cylinder block, the first shielding wall and the second shielding wall are the cylinder block between the first shielding wall and the second shielding wall. It is provided so as to surround the opening of the oil discharge hole on the lower surface of the click.

  According to the said structure, the circumference | surroundings of the opening of the oil discharge hole in the lower surface of a cylinder block are surrounded by the 1st shielding wall and the 2nd shielding wall. For this reason, even if the swirling air accompanying the rotation of the crankshaft flows toward the oil discharged from the opening of the oil discharge hole, the air flow is blocked by the first shielding wall and the second shielding wall. Therefore, it is possible to suppress the oil discharged from the oil discharge hole from being wound or scattered by the swirling air, and to quickly bring the oil to the bottom surface of the oil pan.

1 is a cross-sectional view schematically showing an internal combustion engine. The top view which looked at the crankcase and the balancer housing from the upper side.

  Hereinafter, an embodiment of an internal combustion engine will be described with reference to the drawings. In this embodiment, it is assumed that the internal combustion engine is mounted on the vehicle. And the up-down direction in the state in which the internal combustion engine is mounted on the vehicle is defined as the up-down direction of the internal combustion engine.

  As shown in FIG. 1, the internal combustion engine 10 includes a cylinder block 20 having a substantially rectangular parallelepiped shape as a whole. A cylindrical cylinder 22 is defined in the cylinder block 20. The axis of the cylinder 22 extends in the vertical direction. Four cylinders 22 are provided (only one is shown in FIG. 1). The four cylinders 22 are arranged in a line in the axial direction of the crankshaft 100 of the internal combustion engine 10. In each cylinder 22, a piston (not shown) that reciprocates in the cylinder 22 is disposed.

  In the cylinder block 20, a gap 23 is defined below each cylinder 22. The gap 23 continues to the lower surface of the cylinder block 20. That is, each cylinder 22 communicates with the lower side of the lower surface of the cylinder block 20 via the gap 23. In each gap 23, a connecting rod (not shown) connected to the piston in each cylinder 22 can operate. The connecting rod is connected to the crankshaft 100, and when the internal combustion engine 10 is operated, the reciprocating movement of the piston in the vertical direction is converted into the rotational motion of the crankshaft 100 via the connecting rod.

  As described above, since the four gap portions 23 are arranged side by side, three partition walls 21 that partition the gap portions 23 exist between the adjacent gap portions 23 of the cylinder block 20. On the lower surface of each partition wall 21, a semicircular bearing portion 26 in a plan view is recessed upward. When the direction orthogonal to both the axial direction and the vertical direction of the crankshaft 100 is defined as the width direction of the internal combustion engine 10, the bearing portion 26 is positioned at the approximate center of the partition wall 21 in the width direction of the internal combustion engine 10. .

  An oil discharge hole 24 extending in the vertical direction as a whole is defined on one side in the width direction of the internal combustion engine 10 (on the left side in FIG. 1) from the cylinder 22 and the gap 23 in the cylinder block 20. The oil discharge hole 24 is located at the approximate center in the axial direction of the crankshaft 100 in the cylinder block 20. The oil discharge hole 24 opens on the lower surface of the cylinder block 20. The oil discharge hole 24 communicates with the inside of a cylinder head (not shown), and oil (lubricating oil) from the inside of the cylinder head flows down through the oil discharge hole 24.

  A substantially rectangular plate-shaped crank cap 30 is fixed to the lower surface of each partition wall 21 of the cylinder block 20. Each crank cap 30 has substantially the same thickness as the partition wall 21. Further, the dimension in the longitudinal direction of each crank cap 30 (the length in the left-right direction in FIG. 1) is smaller than the dimension in the width direction of the internal combustion engine 10 at the partition wall 21. Each crank cap 30 is arranged such that its longitudinal direction is along the width direction of the internal combustion engine 10 at each partition wall 21 and its thickness direction is along the thickness direction of each partition wall 21. Note that one end (left side in FIG. 1) in the longitudinal direction of each crank cap 30 is located on the center side in the width direction of the internal combustion engine 10 with respect to the oil discharge hole 24 of the cylinder block 20.

  On the upper surface of each crank cap 30, a semicircular bearing portion 32 in a plan view is recessed downward. The bearing portion 32 of each crank cap 30 is disposed so as to face the bearing portion 26 of each partition wall 21 in the cylinder block 20. With respect to the width direction of the internal combustion engine 10, bolts (not shown) are inserted from below into the respective crank caps 30 on both sides of the bearing portion 32 of each crank cap 30. The bolt penetrates the crank cap 30 in the vertical direction and is screwed into the cylinder block 20. That is, each crank cap 30 is fixed to the cylinder block 20 with a bolt.

The crankshaft 100 is rotatably supported between the bearing portion 32 of each crank cap 30 and the bearing portion 26 of each partition wall 21 in the cylinder block 20.
A generally rectangular parallelepiped balancer housing 70 is fixed to the lower surface of the cylinder block 20 as a whole. The balancer housing 70 is configured such that a lower housing 90 having a substantially rectangular box shape opened to the upper side is connected to a lower side of the upper housing 80 having a substantially rectangular box shape opened to the lower side. Specifically, the upper housing 80 includes an upper wall 82 having a substantially rectangular plate shape and a rectangular cylindrical peripheral wall 84 extending downward from the outer peripheral edge of the upper wall 82. The lower housing 90 includes a substantially rectangular plate-like lower wall 92 and a rectangular cylindrical peripheral wall 94 extending upward from the outer peripheral edge of the lower wall 92. The upper housing 80 and the lower housing 90 are coupled so that the lower end surface of the peripheral wall 84 of the upper housing 80 and the upper end surface of the peripheral wall 94 of the lower housing 90 abut. The balancer housing 70 is arranged such that the width direction thereof is along the width direction of the internal combustion engine 10. The dimension of the balancer housing 70 in the width direction is larger than the dimension of the crank cap 30 in the longitudinal direction.

  A columnar leg 88 extends upward from the upper surface of the upper wall 82 of the upper housing 80. The vertical dimension of the leg portion 88 is larger than the dimension of the crank cap 30 in the short direction (vertical direction). As shown in FIG. 2, a total of six legs 88 are provided, three at each end in the width direction of the balancer housing 70. The three leg portions 88 located at one end (upper side in FIG. 2) in the width direction of the balancer housing 70 are arranged at substantially equal intervals in the longitudinal direction of the balancer housing 70. The three leg portions 88 positioned at the other end portion in the width direction of the balancer housing 70 are disposed at positions facing the three leg portions 88 positioned at the one end portion in the width direction. . That is, three pairs of leg portions 88 facing in the width direction of the balancer housing 70 are arranged in the longitudinal direction of the balancer housing 70.

  As shown in FIG. 1, the three pairs of legs 88 are arranged at the same position as the three partition walls 21 in the cylinder block 20 with respect to the axial direction of the crankshaft 100 (the longitudinal direction of the balancer housing 70). With respect to each of the three pairs of leg portions 88, the leg portion 88 located at the one end portion and the leg portion 88 located at the other end portion are arranged on both sides of the crank cap 30 in the width direction of the internal combustion engine 10. Is arranged.

  The upper end surface of each leg portion 88 is in contact with the lower surface of each partition wall 21 in the cylinder block 20. A bolt (not shown) passes through each leg 88 in the vertical direction. Specifically, a bolt is inserted from the lower side with respect to the peripheral wall 94 of the lower housing 90. The bolt penetrates the peripheral wall 84 and the leg portion 88 of the upper housing 80 and is screwed to the partition wall 21 of the cylinder block 20. As a result, the balancer housing 70 is fixed to the lower surface of the cylinder block 20. In the state where the balancer housing 70 is fixed to the cylinder block 20, the side surface on one side in the width direction (left side in FIG. 1) of the balancer housing 70 is more than the opening of the oil discharge hole 24 on the lower surface of the cylinder block 20. 10 is located on the center side in the width direction.

  A plate-shaped partition wall 86 is bridged between the peripheral walls 84 located on both sides in the width direction of the upper housing 80. Two partition walls 86 are provided in the longitudinal direction of the balancer housing 70. On the lower surface of each partition wall 86, a first bearing portion 86 a having a semicircular shape in plan view is recessed upward. On the lower surface of each partition wall 86, a second bearing part 86b having a semicircular shape in plan view is recessed upward at a position different from the first bearing part 86a. The first bearing portion 86 a and the second bearing portion 86 b are arranged in the width direction of the balancer housing 70. The first bearing portion 86 a and the second bearing portion 86 b provided on one partition wall 86 are the same as the first bearing portion 86 a and the second bearing portion 86 b provided on the other partition wall 86 and the balancer housing 70. It is arranged at the same position in the width direction.

  A plate-like partition wall 96 is bridged between the peripheral walls 94 located on both sides in the width direction of the lower housing 90. Two partition walls 96 are provided in the longitudinal direction of the balancer housing 70. On the upper surface of each partition wall 96, a first bearing portion 96a having a semicircular shape in plan view is recessed downward. On the upper surface of each partition wall 96, a second bearing portion 96b having a semicircular shape in plan view is recessed downward at a position different from the first bearing portion 96a. The first bearing portion 96 a and the second bearing portion 96 b are arranged in the width direction of the balancer housing 70. The first bearing portion 96a and the second bearing portion 96b provided on one partition wall 96 are the same as the first bearing portion 96a and the second bearing portion 96b provided on the other partition wall 96 and the balancer housing 70. It is arranged at the same position in the width direction. Further, the first bearing portion 96 a and the second bearing portion 96 b provided on one partition wall 96 are the first bearing portion 86 a and the second bearing portion 86 b provided on the one partition wall 86 in the upper housing 80. Are arranged to face each other. The first bearing portion 96 a and the second bearing portion 96 b provided on the other partition wall 96 are opposed to the first bearing portion 86 a and the second bearing portion 86 b provided on the other partition wall 86 in the upper housing 80. Are arranged to be.

  A first balancer shaft extending in the axial direction of the crankshaft 100 is interposed between the first bearing portion 86 a of each partition wall 86 in the upper housing 80 and the first bearing portion 96 a of each partition wall 96 in the lower housing 90. 62 is rotatably supported. Here, a part of the upper wall 82 in the upper housing 80 is an opening penetrating in the thickness direction. The first balancer shaft 62 is drivingly connected to the crankshaft 100 through a gear (not shown) through the opening. When the crankshaft 100 rotates, the first balancer shaft 62 rotates in synchronization.

  A second balancer shaft extending in the axial direction of the crankshaft 100 is interposed between the second bearing portion 86 b of each partition wall 86 in the upper housing 80 and the second bearing portion 96 b of each partition wall 96 in the lower housing 90. 64 is rotatably supported. The second balancer shaft 64 is drivingly connected to the first balancer shaft 62 via a gear (not shown) disposed inside the balancer housing 70. And if the 1st balancer shaft 62 rotates, the 2nd balancer shaft 64 will rotate synchronously.

  An unbalanced mass (not shown) is fixed to each of the first balancer shaft 62 and the second balancer shaft 64. The unbalance mass is formed, for example, in a semicircular shape (fan shape), and the center of gravity is eccentric with respect to the respective axis lines of the first balancer shaft 62 and the second balancer shaft 64. When the first balancer shaft 62 rotates, the first balancer shaft 62 rotates in a state where the position of the center of gravity is eccentric with respect to the rotation center. The same applies to the second balancer shaft 64. By rotating the first balancer shaft 62 and the second balancer shaft 64 in such a state, the vibration of the crankshaft 100 caused by the movement of the piston is suppressed. The first balancer shaft 62 and the second balancer shaft 64 constitute a balancer device 60 including an unbalance mass and gears.

  A substantially square box-shaped oil pan 40 is fixed to the lower surface of the cylinder block 20 as a whole. The oil pan 40 has a configuration in which a substantially rectangular box-shaped storage case 42 opened to the upper side is connected to a lower side of a substantially rectangular cylindrical crankcase 50 opened to both the upper side and the lower side. .

  The upper end surface of the crankcase 50 extends along the outer peripheral edge of the lower surface of the cylinder block 20. The crankcase 50 is fixed to the cylinder block 20 so that the upper end surface of the crankcase 50 is in contact with the outer peripheral edge of the lower surface of the cylinder block 20. The crankcase 50 surrounds each crank cap 30 and the balancer housing 70 fixed to the lower surface of each partition wall 21 of the cylinder block 20.

  Oil is stored in the storage case 42. Although illustration is omitted, the storage case 42 houses an oil pump for pumping oil inside the storage case 42. By the operation of the oil pump, oil can be supplied to each part (for example, a cam shaft accommodated in the cylinder head) where lubrication is required in the internal combustion engine 10.

  As shown in FIGS. 1 and 2, a substantially plate-shaped first shielding wall 72 protrudes upward from the upper surface of the upper wall 82 of the upper housing 80 in the balancer housing 70. The first shielding wall 72 protrudes from the end of the balancer housing 70 on one side in the width direction (left side in FIG. 1). The first shielding wall 72 is located at the approximate center in the longitudinal direction of the balancer housing 70. The first shielding wall 72 is an integrally molded product with the upper housing 80.

  As shown in FIG. 2, the schematic shape of the first shielding wall 72 is U-shaped in a plan view from above. Specifically, the first shielding wall 72 includes a plate-like bottom wall portion 72a constituting a U-shaped bottom portion, and one end of the balancer housing 70 in the width direction from one end portion of the bottom wall portion 72a. A plate-like first rising wall portion 72b rising from the other end of the bottom wall portion 72a, and a plate-like second rising wall portion 72c rising to one side in the width direction of the balancer housing 70. ing. The bottom wall portion 72a extends in the longitudinal direction of the balancer housing 70 along the edge of the upper wall 82 of the upper housing 80 in a plan view from above. The dimension of the balancer housing 70 in the longitudinal direction at the bottom wall portion 72 a is larger than the diameter of the oil discharge hole 24 of the cylinder block 20. The first rising wall portion 72 b and the second rising wall portion 72 c extend in the width direction of the balancer housing 70 in a plan view from above. Specifically, the first rising wall portion 72b and the second rising wall portion 72c extend outward from the upper wall 82 from the edge of the upper wall 82 of the upper housing 80 in a plan view from above. The first rising wall portion 72b and the second rising wall portion 72c protrude from the side surface on one side in the width direction of the balancer housing 70 to the inner surface side of the crankcase 50 in a plan view from above. Yes. The dimension in the width direction of the balancer housing 70 of the first rising wall portion 72b and the second rising wall portion 72c is the distance between the side surface on one side in the width direction of the balancer housing 70 and the inner surface of the crankcase 50. About half. That is, in a plan view from the upper side, the respective leading ends of the first rising wall portion 72b and the second rising wall portion 72c are located between the side surface on one side in the width direction of the balancer housing 70 and the inner surface of the crankcase. It reaches near the center.

  As shown in FIG. 1, the bottom wall portion 72a, the first rising wall portion 72b, and the second rising wall portion 72c are erected in the vertical direction. The vertical dimension of the bottom wall part 72a, the first rising wall part 72b, and the second rising wall part 72c is the dimension between the upper wall 82 of the upper housing 80 and the lower surface of the cylinder block 20 (the leg part 88). ). In other words, the upper end portions of the bottom wall portion 72 a, the first rising wall portion 72 b, and the second rising wall portion 72 c reach the lower surface of the cylinder block 20 and abut against the lower surface of the cylinder block 20.

  As shown in FIG. 2, with respect to the axial direction of the crankshaft 100, the bottom wall portion 72 a of the first shielding wall 72 is substantially the same as the opening of the oil discharge hole 24 in the lower surface of the cylinder block 20 (see the two-dot chain line in FIG. 2). It is arranged at the same position. The first shielding wall 72 is formed by the bottom wall portion 72a, the first rising wall portion 72b, and the second rising wall portion 72c so that the opening of the oil discharge hole 24 on the lower surface of the cylinder block 20 is It arrange | positions so that it may surround from the width direction center side.

  As shown in FIGS. 1 and 2, the inner side of the crankcase 50 having a substantially quadrangular cylindrical shape is located on the one side in the width direction of the internal combustion engine 10 from the inner side in the width direction of the internal combustion engine 10. A plate-like second shielding wall 74 protrudes toward the end. The second shielding wall 74 is an integrally molded product with the crankcase 50.

  Two second shielding walls 74 are provided. With respect to the axial direction of the crankshaft 100, the two second shielding walls 74 are located on both sides of the opening of the oil discharge hole 24 on the lower surface of the cylinder block 20. Specifically, with respect to the axial direction of the crankshaft 100, one second shielding wall 74a includes the opening of the oil discharge hole 24 on the lower surface of the cylinder block 20 and the first rising wall portion 72b of the first shielding wall 72. Located between. The other second shielding wall 74 b is located between the opening of the oil discharge hole 24 on the lower surface of the cylinder block 20 and the second rising wall portion 72 c of the first shielding wall 72.

  As shown in FIG. 2, the two second shielding walls 74 are arranged such that their thickness directions are along the axial direction of the crankshaft 100. With respect to the width direction of the internal combustion engine 10, the dimensions of the two second shielding walls 74 substantially coincide with the dimensions of the first rising wall portion 72 b and the second rising wall portion 72 c of the first shielding wall 72. Then, with respect to the width direction of the internal combustion engine 10, the tips of the two second shielding walls 74 reach substantially the same positions as the tips of the first rising wall portion 72b and the second rising wall portion 72c of the first shielding wall 72. Yes.

  As shown in FIG. 1, the two second shielding walls 74 extend in the vertical direction. Regarding the vertical direction, the dimensions of the two second shielding walls 74 substantially coincide with the dimensions of the bottom wall part 72a, the first rising wall part 72b, and the second rising wall part 72c of the first shielding wall 72. . Further, the two second shielding walls 74 are arranged at substantially the same positions as the bottom wall part 72a, the first rising wall part 72b, and the second rising wall part 72c of the first shielding wall 72 in the vertical direction. Yes. That is, the lower end portions of the two second shielding walls 74 reach substantially the same position as the upper surface of the upper wall 82 of the upper housing 80 in the balancer housing 70. Further, the upper ends of the two second shielding walls 74 reach the lower surface of the cylinder block 20 and abut against the lower surface of the cylinder block 20.

  As described above, the first shielding wall 72 is disposed so as to surround the opening of the oil discharge hole 24 on the lower surface of the cylinder block 20 from the center side in the width direction of the internal combustion engine 10. On the other hand, the two second shielding walls 74 are located closer to the end in the width direction of the internal combustion engine 10 than the first shielding wall 72, and the oil on the lower surface of the cylinder block 20 with respect to the axial direction of the crankshaft 100. It is located on both sides of the opening of the discharge hole 24. As a result, the first shielding wall 72 and the two second shielding walls 74a as a whole surround the opening of the oil discharge hole 24 on the lower surface of the cylinder block 20 over a corresponding range (about 270 degrees). . Further, since one second shielding wall 74a and the other second shielding wall 74b are connected to each other on the inner surface of the crankcase 50, the two second shielding walls 74 are located between them. The inner surface of the crankcase 50 and the first shielding wall 72 surround the opening of the oil discharge hole 24 on the lower surface of the cylinder block 20 over the entire circumference (360 degrees).

Next, the operation and effect of this embodiment will be described.
(1) The oil stored in the storage case 42 circulates through the internal combustion engine 10. Specifically, the oil supplied to various parts of the internal combustion engine 10 by the operation of the oil pump lubricates the following parts and then reaches the oil discharge hole 24 in the cylinder block 20. Then, as shown by an arrow A in FIG. 1, the oil flows down through the oil discharge hole 24 and is discharged into the crankcase 50 from the oil discharge hole 24. The oil flows down directly below the opening of the oil discharge hole 24, passes between the side surface on one side in the width direction of the balancer housing 70 and the inner wall surface of the crankcase 50, and returns into the storage case 42.

  Here, as the crankshaft 100 rotates, a swirling flow of air may occur in the crankcase 50. If the opening of the oil discharge hole 24 on the lower surface of the cylinder block 20 is not surrounded by the wall portion, the swirling flow or the air flow derived therefrom is the oil discharged from the oil discharge hole 24 of the cylinder block 20. May be rolled up or scattered. In this case, it is difficult for the oil to reach the bottom surface of the storage case 42 that should return.

  On the other hand, in this embodiment, the opening of the oil discharge hole 24 on the lower surface of the cylinder block 20 is surrounded by the first shielding wall 72 and the second shielding wall 74. Even if the swirl wind accompanying the rotation of the crankshaft 100 flows toward the oil discharged from the oil discharge hole 24, the flow is blocked by the first shielding wall 72 and the second shielding wall 74.

  Specifically, the swirling flow of air accompanying the rotation of the crankshaft 100 and the flow derived therefrom, and in the crankcase 50, at the approximate center in the axial direction of the crankshaft 100 from the center side in the width direction of the internal combustion engine 10 to the end side. The air flow toward (see the arrow W <b> 1 in FIG. 2) is blocked by the bottom wall portion 72 a of the first shielding wall 72. In addition, the above-mentioned flow accompanying rotation of the crankshaft 100 is the flow of air from the axial end of the crankshaft 100 toward the center on the one end in the width direction of the internal combustion engine 10 in the crankcase 50 ( The arrow W2) in FIG. 2 is blocked by the first rising wall 72b and the second rising wall 72c of the first shielding wall 72. Further, in the above-described flow accompanying the rotation of the crankshaft 100, air flowing from the axial end to the center of the crankshaft 100 along the inner wall surface on one side in the width direction of the internal combustion engine 10 in the crankcase 50. The flow (arrow W3 in FIG. 2) is blocked by the two second shielding walls 74.

  In this way, the flow accompanying the rotation of the crankshaft 100 is blocked, so that the flow is prevented from reaching the oil discharged from the oil discharge hole 24 of the cylinder block 20. Therefore, the oil discharged from the oil discharge hole 24 of the cylinder block 20 is suppressed from being wound or scattered by the flow. Therefore, the oil can be quickly brought to the bottom surface of the storage case 42.

  (2) If the upper end portions of the first shielding wall 72 and the second shielding wall 74 do not reach the lower surface of the cylinder block 20, when the air flows with the rotation of the crankshaft 100, The risk of air flowing into the oil discharge hole 24 through the space between the upper ends of the first shielding wall 72 and the second shielding wall 74 and the lower surface of the cylinder block 20 cannot be discarded.

  In this regard, in the present embodiment, the upper ends of the first shielding wall 72 and the second shielding wall 74 reach the lower surface of the cylinder block 20. Therefore, air can be prevented from flowing into the oil discharge hole 24 side with the rotation of the crankshaft 100 from between the upper ends of the first shielding wall 72 and the second shielding wall 74 and the lower surface of the cylinder block 20. .

  (3) One second shielding wall 74 a is arranged at a position shifted from the first rising wall portion 72 b of the first shielding wall 72 with respect to the axial direction of the crankshaft 100. The other second shielding wall 74 b is disposed at a position shifted from the second rising wall portion 72 c of the first shielding wall 72 with respect to the axial direction of the crankshaft 100. Therefore, when the balancer housing 70 and the crankcase 50 are assembled to the lower surface of the cylinder block 20, the assembly position of the balancer housing 70 and the crankcase 50 with respect to the lower surface of the cylinder block 20 depends on the width direction of the internal combustion engine or the axial direction of the crankshaft 100. Even if they are slightly deviated from each other, it is almost impossible for one second shielding wall 74a and the first rising wall portion 72b of the first shielding wall 72 to interfere with each other. Similarly, the other second shielding wall 74b and the second rising wall portion 72c of the first shielding wall 72 do not substantially interfere with each other. Therefore, according to the present embodiment, an error in the assembly position of the balancer housing 70 and the crankcase 50 with respect to the lower surface of the cylinder block 20 can be allowed to some extent.

  (4) Patent Document 1 discloses a configuration in which an extension pipe extending in the vertical direction is connected to the opening of the oil discharge hole 24 on the lower surface of the cylinder block 20. The lower end of the extension pipe disclosed in Patent Document 1 reaches the bottom of the storage case 42. When such a configuration is employed, oil is not easily discharged from the oil discharge hole 24 by the air flow accompanying the rotation of the crankshaft 100. However, in such a configuration, not only the extension pipe but also a connecting member (for example, a bolt) for connecting the extension pipe to the lower surface of the cylinder block 20 is required, and the number of parts increases. Further, connection work for connecting the extension pipe to the lower surface of the cylinder block 20 is also required. Furthermore, if the balancer housing 70 occupies a corresponding area in the oil pan 40, it is necessary to route the extension pipe while avoiding interference with the balancer housing 70. In this case, the space for arranging the extension pipe is ensured and the work of drawing the extension pipe becomes complicated, so in practice, the use of such an extension pipe is not practical.

  On the other hand, the first shielding wall 72 of the present embodiment is an integrally molded product with the upper housing 80 of the balancer housing 70. The second shielding wall 74 is an integrally molded product with the crankcase 50. Therefore, a new member for fixing the first shielding wall 72 and the second shielding wall 74 is not necessary, and connection work is not necessary. Further, the first shielding wall 72 and the second shielding wall 74 can be installed inside the internal combustion engine 10 by assembling the balancer housing 70 and the crankcase 50 to the lower surface of the cylinder block 20. At this time, work such as securing a new space for arranging the first shielding wall 72 and the second shielding wall 74 and adjusting the positions of the first shielding wall 72 and the second shielding wall 74 is unnecessary. It is. That is, there is no particular inconvenience when surrounding the oil discharge hole 24 with the first shielding wall 72 and the second shielding wall 74. Therefore, the configuration related to the first shielding wall 72 and the second shielding wall 74 of the present embodiment is a configuration that can be practically adopted even if the area occupied by the balancer housing 70 in the oil pan 40 is large.

  (5) The two second shielding walls 74, the inner side surface of the crankcase 50 positioned between them, and the first shielding wall 72 define the opening of the oil discharge hole 24 on the lower surface of the cylinder block 20. It surrounds the entire circumference. In addition, each of these wall surfaces continues in the vertical direction. Therefore, each of these wall surfaces defines a guide passage that guides the oil discharged from the oil discharge hole 24 to the lower side. Here, since the bottom wall portion 72 a of the first shielding wall 72 is erected along the edge on one side in the width direction of the balancer housing 70, the oil that has flowed down in the guide passage has a width in the balancer housing 70. It does not flow to the center side in the width direction of the balancer housing 70 from the side surface on one side in the direction. Therefore, the oil can surely flow down between the side surface on one side in the width direction of the balancer housing 70 and the inner surface of the crankcase 50. Therefore, it is possible to suppress the oil from following an unintended flow path and being caught in, for example, the rotation of the crankshaft or evaporating or deteriorating due to the time required to return to the storage case 42.

In addition, this embodiment can be implemented with the following modifications. The present embodiment and the following modifications can be implemented in combination with each other within a technically consistent range.
-When the first shielding wall 72 and the second shielding wall 74 are viewed from the lower surface side of the cylinder block 20, the oil is discharged from the lower surface of the cylinder block 20 by the first shielding wall 72 and the second shielding wall 74. The shape, size, and position can be appropriately changed on condition that the holes 24 are arranged so as to surround the opening. The first shielding wall 72 and the second shielding wall 74 do not need to surround the opening of the oil discharge hole 24 in the cylinder block 20 when viewed from the lower surface side of the cylinder block 20, and the opening May be surrounded in a circumferential direction over a certain range (180 degrees or more). Hereinafter, specific modifications of the first shielding wall 72 and the second shielding wall 74 will be described.

  -The vertical dimension of the 1st shielding wall 72 and the 2nd shielding wall 74 can be changed suitably. The first shielding wall 72 and the second shielding wall 74 may not reach the lower surface of the cylinder block 20. Moreover, the dimension of the up-down direction of the 1st shielding wall 72 and the 2nd shielding wall 74 may mutually differ. Further, in the first shielding wall 72, the bottom wall portion 72 a, the first rising wall portion 72 b, and the second rising wall portion 72 c may have different vertical dimensions, or the two second shielding walls 74. The vertical dimensions may be different from each other.

  -The position of the upper end part of the 1st shielding wall 72 and the upper end part of the 2nd shielding wall 74 may have shifted | deviated to the up-down direction. The positions of the lower end portion of the first shielding wall 72 and the lower end portion of the second shielding wall 74 may be shifted in the vertical direction. However, the 1st shielding wall 72 and the 2nd shielding wall 74 need to be arrange | positioned in the same position of an up-down direction in at least one part of an up-down direction.

  -The dimension, arrangement | positioning, and shape of the 1st standing wall part 72b and the 2nd standing wall part 72c of the 1st shielding wall 72 can be changed suitably. For example, with respect to the width direction of the internal combustion engine 10, the dimensions of the first rising wall portion 72b and the second rising wall portion 72c can be changed as appropriate, and the first rising wall portion 72b and the second rising wall portion The leading end of 72c may reach the inner surface of the crankcase 50. With respect to the width direction of the internal combustion engine 10, the dimensions of the first rising wall 72b and the second rising wall 72c may be different from each other. In addition, when viewed from above, both or one of the first rising wall portion 72b and the second rising wall portion 72c is in the width direction of the internal combustion engine 10 (the width direction of the balancer housing 70). It may be inclined and arranged. Furthermore, both or any one of the 1st standing wall part 72b and the 2nd standing wall part 72c may be arrange | positioned inclined with respect to the up-down direction. Both or any one of the 1st standing wall part 72b and the 2nd standing wall part 72c may be circular arc shape by planar view from the upper side. You may abolish both or any one of the 1st standing wall part 72b and the 2nd standing wall part 72c.

  -The dimension, arrangement | positioning, and shape of the bottom wall part 72a of the 1st shielding wall 72 can be changed suitably. For example, you may change the dimension of the bottom wall part 72a regarding the axial direction (longitudinal direction of the balancer housing 80) of the crankshaft 100 from the structure of the said embodiment. The bottom wall portion 72a may be disposed to be inclined with respect to the axial direction of the crankshaft 100 (longitudinal direction of the balancer housing 80) in a plan view from above. The bottom wall portion 72a may be disposed to be inclined with respect to the vertical direction. The bottom wall portion 72a may have an arc shape in plan view from above. The bottom wall portion 72a may be eliminated.

-The 1st shielding wall 72 does not need to be U-shaped by planar view from the upper side. The first shielding wall 72 may be configured in, for example, an arc shape or a V shape as a whole in plan view from above.
-The size, arrangement, and shape of the two second shielding walls 74 can be changed as appropriate. For example, the dimensions of the two second shielding walls 74 can be appropriately changed with respect to the width direction of the internal combustion engine 10, and the tips of the two second shielding walls 74 reach the bottom wall portion 72 a of the first shielding wall 72. May be. With respect to the width direction of the internal combustion engine 10, the dimensions of the two second shielding walls 74 may be different from each other. Both or one of the two second shielding walls 74 may be disposed so as to be inclined with respect to the width direction of the internal combustion engine 10 in a plan view from above. Both or any one of the two second shielding walls 74 may be arranged to be inclined with respect to the vertical direction. Both or one of the two second shielding walls 74 may be arcuate in a plan view from above. Any one of the two second shielding walls 74 may be eliminated.

  The one second shielding wall 74 a may be located closer to the end side of the internal combustion engine 10 than the first rising wall portion 72 b of the first shielding wall 72 with respect to the axial direction of the crankshaft 100. A similar modification can be applied to the other second shielding wall 74b.

  The first shielding wall 72 may be provided in a portion other than the upper surface of the balancer housing 70. For example, the balancer housing 70 is provided with a wall portion that protrudes from the side surface of the balancer housing 70 to the outside of the side surface. And it is good also as a structure which the 1st shielding wall 72 protrudes upwards from this wall part.

  The first shielding wall 72 may be previously molded separately from the balancer housing 70 and connected to the balancer housing 70 later by an adhesive, bolts, welding, or the like. Similarly, the second shielding wall 74 may be previously molded separately from the crankcase 50 and connected to the crankcase 50 later by an adhesive, bolts, welding, or the like.

  The shape and size of the balancer housing 70 can be appropriately changed on condition that the first balancer shaft 62 and the second balancer shaft 64 can be rotatably supported in synchronization with the crankshaft 100. For example, the side surface on one side in the width direction of the balancer housing 70 may be located on the width direction end side of the internal combustion engine 10 with respect to the opening of the oil discharge hole 24 on the lower surface of the cylinder block 20. However, a gap is required between the side surface of the balancer housing 70 on one side in the width direction and the inner surface of the crankcase 50 for allowing oil to flow down.

  The mechanism for rotating the first balancer shaft 62 and the crankshaft 100 in synchronization is not limited to that using gears, and can be changed as appropriate. For example, a belt or a chain may be used. The same applies to a mechanism for rotating the first balancer shaft 62 and the second balancer shaft 64 in synchronization.

  The position of the oil discharge hole 24 in the cylinder block 20 may be changed with respect to the axial direction of the crankshaft 100. In this case, the positions of the first shielding wall 72 and the second shielding wall 74 may be changed in accordance with the position of the opening of the oil discharge hole 24 on the lower surface of the cylinder block 20.

  In the cylinder block 20, the oil discharge hole 24 may be defined on the other side in the width direction of the internal combustion engine 10 (right side in FIG. 1). Also in this case, the positions of the first shielding wall 72 and the second shielding wall 74 may be changed according to the position of the opening of the oil discharge hole 24.

  The number of cylinders 22 can be changed. The number of partition walls 21 and the number of leg portions 88 in the balancer housing 70 may be changed in accordance with the number of cylinders 22.

DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 20 ... Cylinder block, 24 ... Oil discharge hole, 40 ... Oil pan, 60 ... Balancer apparatus, 70 ... Balancer housing, 72 ... 1st shielding wall, 74 ... 2nd shielding wall.

Claims (1)

An oil pan for storing oil is fixed below the cylinder block, and an internal combustion engine in which a balancer device is disposed inside the oil pan,
The cylinder block has an oil discharge hole that opens on a lower surface of the cylinder block.
A balancer housing that supports the balancer device inside the oil pan is fixed to the lower surface of the cylinder block.
From the outer surface of the balancer housing, a first shielding wall protrudes upward,
From the inner surface of the oil pan, a second shielding wall protrudes toward the first shielding wall,
When the first shielding wall and the second shielding wall are viewed from the lower surface side of the cylinder block, the opening of the oil discharge hole in the lower surface of the cylinder block is the first shielding wall and the second shielding wall. An internal combustion engine provided to surround the engine.