JP2019138260A - Internal combustion engine - Google Patents

Abstract

To inhibit oil from being rolled up on an upper surface of a baffle plate by rotation of a crank shaft.SOLUTION: A cylinder block 20 is provided with an oil discharge hole 24 opening on a lower surface of the cylinder block 20. A crank shaft 100 is rotatably supported between the cylinder block 20 and a crank cap 30. A balancer device 80 is disposed below the crank cap 30 at an interior of an oil pan 40. A plate-like baffle plate 70 covering a balancer shaft 82 from the upper side is disposed between the crank shaft 100 and the balancer shaft 82 of the balancer device 80 within the oil pan 40. An oil circulation passage 72 which penetrates through the baffle plate 70 in a thickness direction is provided at a position of the baffle plate 70 which overlaps with an oil flow-down passage leading from the oil discharge hole 24 to a bottom surface of the oil pan 40.SELECTED DRAWING: Figure 1

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. A crank cap is fixed to the lower surface of the cylinder block inside the oil pan. A crankshaft is rotatably supported between the cylinder block and the crank cap. In addition, a balancer device is disposed below the crank cap in the oil pan. The balancer device includes a balancer shaft that rotates in synchronization with the crankshaft, and an unbalanced mass that is fixed to the balancer shaft. The balancer shaft rotates together with the unbalanced mass, thereby suppressing the crankshaft vibration caused by the movement of the piston.

  In addition, a plate-like baffle plate is disposed between the crankshaft and the balancer shaft inside the oil pan. The baffle plate covers the balancer device from above, and extends over substantially the entire opening range of the oil pan so as to bisect the inside of the oil pan.

Japanese Patent Laid-Open No. 06-017879

  The cylinder block of the internal combustion engine is generally provided with an oil discharge hole that guides oil that has lubricated various parts of the internal combustion engine to the inside of the oil pan. In the internal combustion engine of Patent Document 1, since the inside of the oil pan is divided into two vertically by the baffle plate, the oil discharged from the oil discharge hole tends to accumulate on the upper surface of the baffle plate. If an excessive amount of oil accumulates on the upper surface of the baffle plate, the oil is rolled up with the rotation of the crankshaft and bubbles are easily generated in the oil, or the accumulated oil becomes the rotation resistance of the crankshaft. Therefore, it is not preferable.

  In an internal combustion engine for solving the above problems, an oil pan for storing oil is fixed below the cylinder block, and a balancer device is arranged below the crankshaft inside the oil pan. The cylinder block is provided with an oil discharge hole that opens on a lower surface of the cylinder block, and between the crankshaft and the balancer device in the oil pan, A plate-like baffle plate that covers the balancer device from above is disposed, and the baffle plate is disposed at a position overlapping the oil flow path from the oil discharge hole to the bottom surface of the oil pan in the baffle plate. An oil flow passage penetrating in the thickness direction is provided.

  According to the above-described configuration, the oil discharged from the oil discharge hole reaches the lower side of the baffle plate without being blocked by the baffle plate through the oil flow passage located on the oil flow path. Therefore, an excessive amount of oil does not accumulate on the upper surface of the baffle plate. Therefore, oil can be prevented from being caught in the rotation of the crankshaft on the upper surface of the baffle plate.

  In the internal combustion engine, the oil flow passage may be located directly below the opening of the oil discharge hole in the lower surface of the cylinder block in a state where the internal combustion engine is mounted on a vehicle.

  According to the above configuration, if the oil flowing down from the oil discharge hole falls as it is, the oil reaches below the baffle plate via the oil flow passage. Therefore, even if there is no special configuration for guiding the oil to the oil flow passage, the oil can be efficiently brought down below the baffle plate.

1 is a cross-sectional view schematically showing an internal combustion engine. The top view which looked at the crankcase 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. The vertical direction when the internal combustion engine is mounted on the vehicle is defined as the up-down direction.

  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. A plurality of cylinders 22 are provided (only one is shown in FIG. 1). The plurality of 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 engine is operated, the reciprocating movement of the piston in the vertical direction in the figure is converted into the rotational motion of the crankshaft 100 via the connecting rod.

  As described above, since the plurality of gap portions 23 are arranged side by side, the 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 perpendicular 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. Yes.

  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 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 length of each crank cap 30 in the longitudinal direction (the length in the left-right direction in FIG. 1) is shorter than the length of the partition wall 21 in the width direction of the internal combustion engine 10. 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 the end of each crank cap 30 on one side in the longitudinal direction (left side in FIG. 1) 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, on both sides of the bearing portion 32 of each crank cap 30, bolts B <b> 1 are inserted from the lower side with respect to each crank cap 30. The bolt B1 passes through 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 by the bolt B1.

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 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 rectangular box-shaped storage case 60 opened upward is connected to the lower side of a rectangular box-shaped crankcase 50 opened upward.

  The crankcase 50 includes a substantially square plate-like bottom wall 52 and a rectangular tubular peripheral wall 51 extending upward from the outer peripheral edge of the bottom wall 52. The upper end surface of the peripheral wall 51 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 such that the upper end surface of the peripheral wall 51 is in contact with the outer peripheral edge of the lower surface of the cylinder block 20. As described above, each crank cap 30 is fixed to the lower surface of each partition wall 21 of the cylinder block 20, so that the peripheral wall 51 of the crankcase 50 surrounds each crank cap 30.

  As shown in FIGS. 1 and 2, an opening 52 a passes through the bottom wall 52 in the vertical direction. In this embodiment, the opening 52a has a rectangular shape in plan view. Further, the opening range of the opening 52 a reaches most of the extending range of the bottom wall 52. Further, the position of the opening 52 a is determined so as to include the entire region of the opening 24 a of the oil discharge hole 24 on the lower surface of the cylinder block 20 when the internal combustion engine 10 is viewed from above.

  As shown in FIG. 1, a generally rectangular parallelepiped bearing forming portion 54 protrudes upward from the bottom wall 52 as a whole. As shown in FIG. 2, one bearing forming portion 54 is provided on each side of the crankshaft 100 in the axial direction across the opening 52 a. The two bearing forming portions 54 are disposed at the same position in the width direction of the internal combustion engine 10 and face the axial direction of the crankshaft 100. As shown in FIG. 1, on the upper surfaces of the two bearing forming portions 54, a semicircular bearing portion 54 a in plan view is recessed downward.

  A substantially rectangular parallelepiped balancer cap 42 is fixed to each of the upper surfaces of the two bearing forming portions 54. From the lower surface of the balancer cap 42, a semicircular bearing portion 42a in plan view is recessed upward. The balancer cap 42 is disposed such that the bearing portion 42a faces the bearing portion 54a of the bearing forming portion 54. On both sides of the bearing portion 42 a of each balancer cap 42, the bolt B <b> 2 is inserted from above with respect to each balancer cap 42. The bolt B <b> 2 penetrates the balancer cap 42 in the vertical direction and is screwed into the bearing forming portion 54. That is, the balancer cap 42 is fixed to the bearing forming portion 54 by the bolt B2.

  A balancer shaft 82 extending in the axial direction of the crankshaft 100 is rotatably supported between the bearing portion 42 a of each balancer cap 42 and the bearing portion 54 a of each bearing forming portion 54.

  As shown in FIG. 2, a driven gear 84 is provided on the balancer shaft 82 on the outer side in the axial direction of the crankshaft 100 than the one bearing forming portion 54. The driven gear 84 is fixed to the balancer shaft 82 and rotates integrally with the balancer shaft 82. The driven gear 84 is drivingly connected to the crankshaft 100 via a gear (not shown). When the crankshaft 100 rotates, the balancer shaft 82 rotates in synchronization.

  An unbalanced mass 86 is provided on the balancer shaft 82 outside the driven gear 84 in the axial direction of the crankshaft 100. The unbalance mass 86 is fixed to the balancer shaft 82 and rotates integrally with the balancer shaft 82. The unbalance mass 86 is formed, for example, in a semicircular shape (fan shape), and the center of gravity is eccentric with respect to the axis of the balancer shaft 82. When the balancer shaft 82 rotates, the balancer shaft 82 rotates in a state where the position of the center of gravity is eccentric with respect to the rotation center. As a result, the vibration of the crankshaft 100 that occurs with the movement of the piston is suppressed. The balancer shaft 82, the driven gear 84, and the unbalance mass 86 constitute a balancer device 80. Since the balancer device 80 is disposed on the bottom wall 52 of the crankcase 50, the balancer device 80 is located below the crankshaft 100 located on the lower surface of the cylinder block 20 inside the oil pan 40.

  As shown in FIG. 1, oil is stored in the storage case 60. Although illustration is omitted, the storage case 60 contains an inlet of an oil pump for pumping oil inside the storage case 60. 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 FIG. 1, a baffle plate 70 is disposed between the crankshaft 100 and the balancer device 80 inside the oil pan 40. Specifically, as shown in FIGS. 1 and 2, a quadrangular prism-like boss portion 56 protrudes upward from the bottom wall 52 of the crankcase 50. A total of four bosses 56 are provided, two on each side in the width direction of the internal combustion engine 10 across the opening 52a. The upper end surfaces of the four boss portions 56 protrude to the upper side of the balancer shaft 82 supported by the two bearing forming portions 54. A plate-like baffle plate 70 is attached to the upper end surfaces of the four boss portions 56. Bolts B <b> 3 are inserted into the four boss portions 56 from the upper side of the baffle plate 70. Each bolt B <b> 3 penetrates the baffle plate 70 in the vertical direction and is screwed into the four boss portions 56. That is, the balancer cap 42 is fixed to the four boss portions 56 by the bolt B3.

  As a whole, the baffle plate 70 has a quadrangular shape with a size covering substantially the entire area of the opening 52a. The baffle plate 70 is located between the two bearing forming portions 54 with respect to the axial direction of the crankshaft 100. Since the upper end surfaces of the four boss portions 56 protrude to the upper side of the balancer shaft 82, the baffle plate 70 covers the balancer shaft 82 from the upper side.

  An oil flow passage 72 that is a space penetrating the baffle plate 70 in the thickness direction is provided in the baffle plate 70 at a position directly below the oil discharge hole 24 of the cylinder block 20. In this embodiment, the oil flow passage 72 has a shape in which one of the four corners of the quadrangular shape is cut out into a quadrangular shape. When the internal combustion engine 10 is viewed from above, a part of the opening 52a of the crankcase 50 is exposed from the baffle plate 70 in the portion where the oil flow passage 72 is provided (dot region in FIG. 2). The area of the exposed portion is larger than the area of the opening 24 a of the oil discharge hole 24 on the lower surface of the cylinder block 20. Furthermore, when the internal combustion engine 10 is viewed from above, the entire area of the opening 24a of the oil discharge hole 24 is within the range of the exposed portion.

Next, the operation and effect of this embodiment will be described.
(1) The oil stored in the storage case 60 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, the oil flows down through the oil discharge hole 24 and is discharged from the oil discharge hole 24 into the crankcase 50. As shown by the arrow A in FIG. 1, the oil discharged from the oil discharge hole 24 flows down directly in the vertical direction and heads toward the storage case 60. In other words, in the present embodiment, the oil flow path from the oil discharge hole 24 to the bottom surface of the storage case 60 is directly below the oil discharge hole 24 in the vertical direction.

  In the present embodiment, the oil flow passage 72 is provided in the baffle plate 70 at a position immediately below the oil discharge hole 24 in the vertical direction (position overlapping the oil flow path). Therefore, the oil discharged from the oil discharge hole 24 reaches the lower side of the baffle plate 70 without being blocked by the baffle plate 70 through the oil flow passage 72 positioned on the oil flow path, and the storage case 60. Return to. Therefore, an excessive amount of oil does not collect on the upper surface of the baffle plate 70. Therefore, oil can be prevented from being caught in the rotation of the crankshaft 100 on the upper surface of the baffle plate 70.

  (2) By the way, it is assumed that the oil flow passage 72 is not located directly below the oil discharge hole 24 in the vertical direction. In this case, if the oil discharged from the oil discharge hole 24 falls as it is, the oil may reach the upper surface of the baffle plate 70 and be stored on the upper surface. Therefore, when the oil flow path 72 is not positioned directly below the oil discharge hole 24, a guide wall for guiding oil is provided in the crankcase 50 as a configuration for guiding the oil to the oil flow path 72. It is conceivable to provide it. However, providing such a guide wall complicates the shape of the crankcase 50.

  On the other hand, according to the present embodiment, the oil flow passage 72 is located immediately below the oil discharge hole 24 in the vertical direction. Therefore, if the oil flowing down from the oil discharge hole 24 falls as it is, the oil reaches the lower side than the baffle plate 70 through the oil flow passage 72. That is, even if there is no special configuration for guiding the oil to the oil flow passage 72, the oil can be efficiently brought down below the baffle plate 70. Therefore, according to the present embodiment, the configuration of the crankcase 50 is simplified, which contributes to, for example, simplification of the configuration of a mold for manufacturing the crankcase 50.

  (3) Temporarily, the area of the opening 52a of the crankcase 50 exposed from the baffle plate 70 (dot area in FIG. 2) is larger than the area of the opening 24a of the oil discharge hole 24 on the lower surface of the cylinder block 20. Is also small. In this case, when the internal combustion engine 10 is viewed from above, a part of the baffle plate 70 is located within the range of the opening 24 a of the oil discharge hole 24 on the lower surface of the cylinder block 20. That is, a part of the baffle plate 70 is located immediately below a part within the range of the opening 24 a of the oil discharge hole 24. In this case, a part of the oil discharged from the oil discharge hole 24 may reach the upper surface of the baffle plate 70 without reaching the oil flow path 72. The oil may be stored on the upper surface of the baffle plate 70.

  In this regard, in this embodiment, the area of the portion (dot region in FIG. 2) exposed from the baffle plate 70 in the opening 52 a of the crankcase 50 is equal to the opening 24 a of the oil discharge hole 24 in the lower surface of the cylinder block 20. It is larger than the area. That is, the baffle plate 70 is not located immediately below the opening 24a in the entire area of the opening 24a of the oil discharge hole 24 on the lower surface of the cylinder block 20. Therefore, the oil discharged from the oil discharge hole 24 reliably reaches the lower side of the baffle plate 70 without being blocked by the baffle plate 70.

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.
The shape of the notch corresponding to the oil flow passage 72 is not limited to a quadrangle, and may be a polygon other than a quadrangle or an arc. Further, the oil flow passage 72 may be configured by a through-hole penetrating the baffle plate 70 in the thickness direction. The plan view shape of the through hole may be any shape such as a polygonal shape or an arc shape. That is, the oil flow path 72 is a position that overlaps with the oil flow path from the oil discharge hole 24 to the bottom surface of the storage case 60 in the baffle plate 70, as long as it penetrates the baffle plate 70 in the thickness direction. The shape can be changed as appropriate.

  The area of the opening 52 a of the crankcase 50 that is exposed from the baffle plate 70 (dot region in FIG. 2) may be smaller than the area of the opening 24 a of the oil discharge hole 24 on the lower surface of the cylinder block 20. . If there is no extreme difference between these two areas, most of the oil discharged from the oil discharge hole 24 reaches the oil flow path 72 without being blocked by the baffle plate 70. Even if it is large, not a little oil can be brought below the baffle plate 70 through the oil flow passage 72.

  -Depending on the posture of the internal combustion engine 10 when mounted on a vehicle, the oil discharge hole 24 may not be directly below the oil flow path. For example, a path through which oil reaches the bottom surface of the storage case 60 from the opening 24a of the oil discharge hole 24 through the lower surface of the cylinder block 20 and the inner wall surface of the crankcase 50 may be an oil flow-down path. If a guide wall or the like for guiding the oil toward the inner wall surface of the crankcase 50 is provided and the oil flow path is fixed, the oil flow path 72 (cut off) is positioned at a position overlapping the flow path on the baffle plate 70. (Notch) may be provided.

  The shape and dimensions of the baffle plate 70 can be changed as appropriate. However, the baffle plate 70 is plate-shaped and needs to cover most of the balancer shaft 82. The baffle plate 70 may be sized to cover not only the balancer shaft 82 but also the driven gear 84 and the unbalance mass 86. In this case, it is necessary to provide an opening at a position above the driven gear 84 in the baffle plate 70 so that the driven gear 84 can mesh with other gears. The baffle plate 70 may be configured such that openings are provided at some or a plurality of positions on the upper side of the balancer shaft 82 so that the balancer shaft 82 is partially exposed from the baffle plate 70. You may provide an opening in parts other than the position which becomes the upper side of the balancer shaft 82 in the baffle plate 70.

  A funnel-shaped wall portion that protrudes from the upper surface and increases in diameter toward the upper side may be provided on a portion of the upper surface of the baffle plate 70 that is positioned around the oil flow passage 72. Providing such a wall makes it easier for oil to reach the oil flow passage 72.

  The upper surface of the baffle plate 70 may be an inclined surface that goes down toward the oil flow passage 72. In this way, even if oil splatters on the upper surface of the baffle plate 70, the oil is guided to the oil flow passage 72, so that an excessive amount of oil does not accumulate on the upper surface of the baffle plate 70.

  The shape, position, and number of the boss portions 56 that support the baffle plate 70 can be changed as appropriate. The boss portion 56 only needs to be configured to be able to support the baffle plate 70 above the balancer shaft 82.

  The shape, position, and number of the bearing forming portion 54 and the balancer cap 42 that support the balancer shaft 82 can be changed as appropriate. The bearing forming portion 54 and the balancer cap 42 may be configured to be able to support the balancer shaft 82 so as to be parallel and rotatable with the crankshaft 100.

  The shape and opening range of the opening 52a of the crankcase 50 can be changed as appropriate. However, it is necessary to provide the opening 52 a so that the oil can return to the storage case 60. The opening 52a may be divided into a plurality.

  The mechanism for rotating the balancer shaft 82 and the crankshaft 100 in synchronism is not limited to gear engagement, and can be changed as appropriate. For example, the balancer shaft 82 and the crankshaft 100 may be rotated synchronously using a belt or a chain.

  -The balancer apparatus 80 can change the structure suitably on condition that the vibration of the crankshaft 100 which arises with the motion of a piston can be suppressed. For example, the position and number of the driven gear 84 and the unbalance mass 86 may be changed. Two or more balancer shafts 82 each having an unbalance mass 86 may be provided.

  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). In this case, an oil flow path 72 may be provided in the baffle plate 70 at a position overlapping with the oil flow path from the oil discharge hole 24.

  The end of one side (left side in FIG. 1) in the longitudinal direction of the crank cap 30 may be located on the end side in the width direction of the internal combustion engine 10 with respect to the oil discharge hole 24 of the cylinder block 20. In this case, a through-hole that penetrates the crank cap 30 substantially vertically and communicates with the oil discharge hole 24 may be provided at a position below the oil discharge hole 24 in the crank cap 30. In this modified example, the through hole of the crank cap 30 constitutes a part of the oil flow path.

A so-called ladder frame type structure in which both end portions in the longitudinal direction of the crank cap 30 are coupled to the peripheral wall 51 of the crankcase 50 may be adopted.
The number of cylinders 22 can be changed. The number of partition walls 21 and the number of crank caps 30 are changed according to the number of cylinders 22.

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 20 ... Cylinder block, 24 ... Oil discharge hole, 30 ... Crank cap, 40 ... Oil pan, 50 ... Crank case, 60 ... Storage case, 70 ... Baffle plate, 72 ... Oil flow path, 80 ... Balancer Device, 82 ... balancer shaft, 100 ... crankshaft.

Claims (2)

An internal combustion engine in which an oil pan for storing oil is fixed below the cylinder block, and a balancer device is arranged below the crankshaft inside the oil pan,
The cylinder block is provided with an oil discharge hole that opens on the lower surface of the cylinder block.
Between the crankshaft and the balancer device in the oil pan, a plate-like baffle plate that covers the balancer device from above is disposed,
In the baffle plate, an oil flow passage that penetrates the baffle plate in the thickness direction is provided at a position overlapping the oil flow path from the oil discharge hole to the bottom surface of the oil pan. The internal combustion engine according to claim 1,
The oil flow passage is located immediately below the opening of the oil discharge hole in the lower surface of the cylinder block in a state where the internal combustion engine is mounted on a vehicle.