JP6653053B2 - Cylinder block - Google Patents

Description

  The present invention relates to a cylinder block.

  The cylinder block provided in the internal combustion engine is provided with an oil flow-down passage (oil drop passage) for returning the oil injected to the intake / exhaust cam and the rocker arm to the crankcase. A configuration in which a communication path is provided in the middle of the oil flow-down path is disclosed.

  For example, in Patent Literature 1, a hollow portion formed by casting using a core mold is provided below a tap hole for a head bolt provided in a cylinder block, and the hollow portion traverses an oil drop passage on a side surface of the cylinder block. A configuration provided to be open is disclosed.

  Patent Literature 2 discloses a cylinder block in which a cylinder head bolt hole and an oil return hole are provided in a journal portion between cylinders. A thick hole extending in the lateral direction is provided in a thick portion below the cylinder head bolt hole, and the thin hole constitutes a part of the oil return hole, and is, for example, a cast hole.

  Patent Document 3 discloses a configuration in which an oil chamber (hole) formed by casting is provided in an oil drop passage.

JP-A-2004-190630 JP 2005-16418 A JP 2009-270507 A

  In the configuration in which the communication path is provided in the middle of the oil flow path, the flow of the oil may be impaired by rotation of the crankshaft. For example, if the opening of the communication passage is located near the crank arm or the balance weight that constitutes the crankshaft, air generated by rotation of the crank arm or the balance weight may flow into the communication passage and hinder the oil flow. There is.

  An object of the disclosed cylinder block is to allow oil in an oil flow passage to flow smoothly.

  The disclosed cylinder block is a cylinder block including a crankshaft in which a crank arm including a balance weight is interposed between a plurality of crank journals, wherein the plurality of cylinder bores are arranged in a crankshaft direction; And a crankcase portion having a bearing portion rotatably supporting the crank journal, extending downward between the plurality of cylinder bores, and extending from a cylinder head side to the crankcase portion side. An oil flow path for flowing down oil, and a communication hole opened at a position deviated from the rotation radial direction of the crank arm and the balance weight to communicate the oil flow path with the inside of the crankcase portion are provided.

  A crank journal wall which is located between a lower end of the cylinder bore and the bearing portion and partitions a cylinder-corresponding space of the crankcase portion, wherein an opening of the communication passage faces and is adjacent to and sandwiches the crank journal; The crank journal wall may be provided between the pair of crank arms.

  The communication hole may further include a notch provided on a side of the communication hole opposite to the oil flow-down path, and communicating a side surface of the bulk wall with the communication hole.

  ADVANTAGE OF THE INVENTION According to the cylinder block of an indication, the oil of an oil flow-down path can flow down smoothly.

FIG. 2 is a cross-sectional view schematically illustrating an engine. FIG. 3 is a sectional view schematically illustrating a part of a cylinder block. It is sectional drawing which illustrates typically the relationship between an oil flow-down path and a communication hole. It is sectional drawing which illustrates typically the type | mold used for casting.

  Hereinafter, a diesel engine 1 (an example of an internal combustion engine, hereinafter simply referred to as an engine 1) according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  The engine 1 includes a cylinder block 2 and a cylinder head 3. An upper half portion of the cylinder block 2 is a cylinder portion 4, in which a plurality of cylinder bores 5 extending in the vertical direction are arranged in series in the longitudinal direction of the engine 1 (crank shaft direction) with a bulk wall 6 interposed therebetween. A piston 7 is housed in each cylinder bore 5 in a reciprocable manner.

  A crankcase portion 10 is provided at a lower end of the cylinder bore 5, that is, at an end on the bottom dead center side of the piston 7. A crankshaft 11 is rotatably arranged in the crankcase 10. The crankshaft 11 is a rotating shaft that converts the reciprocating motion of the piston 7 into a rotational force, and is attached between a plurality of crank journals 11A, a crank arm 13 fixed to the crank journal 11A, and a pair of opposed crank arms 13. And a balance weight 13A provided on a side of the crank arm 13 opposite to the crank pin 12. The large end of the connecting rod 8 is rotatably attached to the crank pin 12. The small-diameter portion of the connecting rod 8 is rotatably attached to a piston pin 7 a of the piston 7.

  A crank bearing 15 is provided in the crankcase 10 so as to be continuous with the bulk wall 6. The crank bearing 15 is a bearing that rotatably supports the crank journal of the crankshaft 11.

  An oil strainer 21, an oil pump 22, and an oil supply path 23 are provided as an oil supply mechanism 20 in the crankcase section 10. The oil stored in the crankcase 10 is sent to the cylinder head 3 by the oil supply mechanism 20.

  As shown in FIG. 1, a rocker arm shaft 31 is arranged on the cylinder head 3. The rocker arm shaft 31 is a hollow shaft that swingably supports the rocker arm 32, and has an oil passage 33 through which oil from the oil supply passage 23 flows. The oil flowing through the oil passage 33 is injected to the intake / exhaust cam 35 and the camshaft 36. When the rocker arm 32 swings according to the cam profile of the intake / exhaust cam 35, the intake / exhaust valve 34 moves up and down in accordance with the swing of the rocker arm 32. As a result, the intake / exhaust valve 34 is opened and closed in conjunction with the reciprocating movement of the piston 7.

  As shown in FIG. 2, the cylinder block 2 is provided with an oil flow passage 41 that penetrates the cylinder bore 5 along the top dead center side and the bottom dead center side along the bulk wall 6. The oil flow passage 41 is configured as a vertically long flow passage, and guides oil injected into the cylinder head 3 to the crankcase portion 10. The oil flow passage 41 of this embodiment is provided one between the second and third cylinder bores 5 from the left in FIG. 2 and one on the right side of the rightmost cylinder bore 5.

  The crank journal wall 16 of the cylinder block 2, which is located between the lower end of the cylinder bore 5 and the crank bearing 15 and separates the space corresponding to the cylinder of the crankcase 10, has a communication passage 42 communicating with the oil flow-down passage 41. Is provided. The communication path 42 is configured as a short flow path in a direction substantially orthogonal to the flow direction of the oil flow path 41.

  More specifically, the opening of the communication passage 42 is located between the cylinder bore 5 and the crank bearing portion 15 and is not exposed to air generated by rotation of the crank arm 13 and the balance weight 13A (both shown in FIG. 1). It is provided in. In the present embodiment, the opening of the communication passage 42 is provided in the crank journal wall 16 near the crank bearing portion 15 located between the pair of adjacent crank arms 13 with the crank journal 11A interposed therebetween. As described above, by providing the opening of the communication passage 42 at a position deviated from the rotation radial direction (rotation locus) of the crank arm 13 and the balance weight 13A, the inflow of air generated by rotation into the communication passage 42 can be prevented. Has become.

  As shown in detail in FIG. 3, a cutout portion 43 is provided in the communication passage 42 on the side opposite to the oil flow-down passage 41 (on the crankshaft 11 side). The notch 43 is provided by locally depressing the side surface of the bulk wall 6.

  FIG. 4 shows a part of a mold 51 for producing a cylinder block. The mold 51 is made by solidifying sand, and has a channel 52 for molten metal (molten metal) provided therein. A column 53 is provided in a portion to be the communication path 42.

  The cylinder block 2 is manufactured by placing a top 53 on a sand mold portion of the mold 51 corresponding to the oil flow passage 41 and injecting a molten metal into the flow passage 52 from above and cooling it. In the present embodiment, since the communication path 42 is formed using the top 53, the deformation of the oil flow-down path 41 can be effectively suppressed even if the communication path 42 is provided thin.

  Next, the operation of the present embodiment will be described.

  As described with reference to FIG. 1, when the engine 1 operates, the oil stored in the crankcase portion 10 is sent out to the cylinder head 3 by the oil supply mechanism 20. The oil sent to the cylinder head 3 is collected in an oil flow passage 41 provided in the cylinder block 2 and flows down the oil flow passage 41.

  As described with reference to FIGS. 2 and 3, in the cylinder block 2 of the present embodiment, the opening of the communication passage 42 is located between the pair of adjacent crank arms 13 opposed to each other across the crank journal 11 </ b> A. Since it is provided on the crank journal wall 16 in the vicinity of 15, even if air flows due to rotation of the crank arm 13 and the balance weight 13 </ b> A, this air hardly flows into the communication passage 42. Therefore, the oil in the oil flow passage 41 can flow down smoothly.

  Further, as described with reference to FIG. 3, since the notch 43 is provided in the crankshaft 11 rather than the communication path 42, the flow path is bent, so that the inflow of air can be effectively suppressed. Also at this point, the oil in the oil flow passage 41 can flow down smoothly.

  The above description of the embodiments is for facilitating the understanding of the present invention, and does not limit the present invention. The present invention can be modified and improved without departing from the spirit thereof, and the present invention includes equivalents thereof.

  For example, the internal combustion engine is not limited to the diesel engine 1. The same applies to gasoline engines.

  Further, the number of the oil flow passages 41 is not limited to two. The number may be one, or three or more.

DESCRIPTION OF SYMBOLS 1 ... Diesel engine, 2 ... Cylinder block, 3 ... Cylinder head, 4 ... Cylinder part, 5 ... Cylinder, 6 ... Bulk wall, 7 ... Piston, 7a ... Piston pin, 8 ... Connecting rod, 10 ... Crankcase part, 11 ... Crank shaft, 11A ... Crank journal, 12 ... Crank pin, 13 ... Crank arm, 13A ... Balance weight, 15 ... Crank bearing part, 16 ... Crank journal wall, 20 ... Oil supply mechanism, 21 ... Oil strainer, 22 ... Oil Pump, 23 oil supply passage, 31 rocker arm shaft, 32 rocker arm, 33 oil passage, 34 intake / exhaust valve, 35 intake / exhaust cam, 36 cam shaft, 41 oil flow down passage, 42 ... Communication hole 43, notch, 51 mold, 52 flow path for molten metal, 53 frame

Claims (3)

A cylinder block including a crankshaft in which a crank arm including a balance weight is interposed between a plurality of crank journals,
A plurality of cylinder bores arranged in the direction of the crankshaft;
A crankcase portion provided below the plurality of cylinder bores and having a bearing portion rotatably supporting the crank journal;
A crank journal wall positioned between the lower end of the cylinder bore and the bearing portion to partition a cylinder-corresponding space of the crankcase portion, and a side surface of which extends in a direction intersecting the crankshaft direction;
An oil flow-down path extending downward between the plurality of cylinder bores and allowing oil to flow from the cylinder head side to the crankcase section side;
Wherein provided on the crank journal wall, the side surface of the crank arm and the crank journal walls deviating from the rotation radial direction of the balance weight located between the pair of the crank arm facing adjacent across said crank journal And a communication hole that communicates with the oil flow passage and the inside of the crankcase portion. The oil flows down passage and provided on the opposite side, the cylinder block according to claim 1, further comprising a cutout portion which communicates the side and the communication hole of the crank journal wall of the communication hole. The notch is provided by depressing the side surface of the crank journal wall.
  The cylinder block according to claim 2.

Images