JPH0636275Y2 - Engine cooling structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an engine cooling structure in which lubricating oil is used to cool the engine, and a flywheel is also used to cool the engine, and particularly to a casing. The present invention relates to the structure of a connection oil passage that connects the cooling passage on the side of the vehicle with the heat radiation oil passage on the side of the flywheel.

[Prior Art] In an engine that cools an engine by guiding lubricating oil to a cooling passage formed in a casing, a heat radiation oil passage is formed in a flywheel provided at an end of a crankshaft projecting outward from the casing to dissipate the oil. There is an attempt to cool the oil by guiding it to a passage (see Japanese Patent Application Nos. 62-308974 and 308975 proposed by the applicant).

[Problems to be solved by the invention] However, in Japanese Patent Application Nos. 62-308974 and 308975, when the cooling passage on the casing side and the radiating oil passage on the flywheel side are connected without using external piping, It is necessary to form two connecting passages, one for the forward path and one for the returning path, in the crankshaft, and the machining of the two connecting passages in the shaft is complicated.

Therefore, the object of the present invention is to provide only one passage in the crankshaft for each reciprocating connection passage that connects the casing-side cooling passage and the flywheel-side radiating oil passage. Another object of the present invention is to provide a cooling structure for an engine which simplifies the passage machining as well as the above.

[Means for Solving the Problems] In order to achieve the above objects, the present invention introduces lubricating oil into a cooling passage formed in a casing to cool an engine,
An engine for cooling oil by guiding also to a heat dissipation passage formed in a flywheel provided at an end of a crankshaft protruding outward from the casing, for an outbound path connecting the cooling passage and the heat dissipation passage And one of the two return passage connecting passages is formed in the crankshaft, and the other connecting oil passage is formed in the fitting portion between the crankshaft and the flywheel. Characterize.

[Operation] Of the two reciprocating connection passages that connect the casing-side cooling passage and the flywheel-side radiating oil passage, only one connection passage needs to be formed in the crankshaft. In addition, since the other connecting oil passage is formed in the fitting portion between the crankshaft and the flywheel, the processing of the connecting passage can be facilitated together with the processing of the axial passage.

[Example] An example will be described below with reference to the accompanying drawings.

In the drawings showing an engine to which the present invention is applied, 1 is a piston, 3 is a connecting rod, 5 is a crankshaft, 10 is a cylinder barrel that forms the casing body of the engine, 15 is an oil pan, and 17 is a casing body and a separate casing body. The cylinder head of the body, 19 is a head cover.

Single cylinder OHV with crankshaft 5 placed vertically as shown
Type engine, the crankpin portion 6 of the crankshaft 5
A lower shaft portion 7 extending downward is supported by a thick bearing portion 16 provided on the oil pan 15 via a bearing as shown in the drawing. The upper shaft portion 8 extending upward from the crank pin portion 6 of the crank shaft 5 is a crank case portion 11 of the cylinder barrel 10.
Also, it is directly supported by a thick bearing portion 14 provided between the cylinder block portion 13 as shown in the figure.

Further, a cam shaft 21 is arranged in the crank case portion 11 in parallel with the crank shaft 5, and a gear is provided from the crank shaft 5 to the cam shaft 21.
The rotation is transmitted by 9,22, and the camshaft
Each push rod 23 and cylinder head 17 that engage with 21
Intake and exhaust valves (not shown) are opened and closed via the respective rocker arms 24 above. An upper end of the cam shaft 21 is directly supported by a bearing portion 12 provided on the crankcase portion 11, and a lower end of the cam shaft 21 is connected to an oil pump 25 installed in an oil pan 15. That is, the cam shaft 21 is connected to the pump drive shaft 27 in the pump case 26 via the connecting member 28 as shown in the drawing.

The flywheel is attached to the end of the upper shaft portion 8 protruding outward (upward in the drawing) from the cylinder barrel 10 of the crankshaft 5.
31 is provided by bolt connection as shown. The flywheel 31 is a flywheel body 33 and a fin side ring plate.
The lower boss portion 34 of the flywheel main body 33 faces the inner circumference of the bearing portion 14 with a space as shown in the drawing.

In the above engine, the lubricating oil O stored in the oil pan 15 that also serves as engine cooling flows into the suction port 29 of the pump case 26, and is discharged by the driving of the pump 25, so that the cam shaft is described below. Pumped into 21.

That is, in order to guide the oil in the pump 25, the connecting passage 28 has a radial passage 41 and an axial passage 42 opening to the upper end.
And a passage 43 in the axial direction that opens to both upper and lower ends is formed in the cam shaft 21, and a passage 44 is formed in the bearing portion 12 so as to face the passage 43. A passage 45 communicating with the above and opening to the inner circumference of the bearing portion 14 is formed in the crankcase 11.

In the upper shaft portion 8 of the crankshaft 5, a groove 46 in the circumferential direction facing the open end of the passage 45, a radial passage 47 communicating with the passage 46, and a passage 47 in the radial direction. An axial passage 48 communicating with the axial direction and a radial passage 49 facing the inner circumference of the flywheel 31 are formed.

Further, a radial passage 51 is formed in the flywheel body 33 of the flywheel 31 so as to face the passage 49, and the fin side annular plate body 35 communicates with the passage 51 and has a spiral shape or a maze as shown in the drawing. A long heat dissipation jacket 52 is formed. The flywheel main body 33 is formed with a passage 53 to the joint surface side and a passage 54 opening to the inner periphery so as to communicate with the outer peripheral side of the heat dissipation jacket 52.

Here, the opening end on the inner peripheral side of the passage 51 is oil-tightly sealed by upper and lower O-rings 55, 55 fitted and interposed between the crankshaft upper shaft portion 8 and the flywheel main body 33 as shown in the figure. The upper end of the heat dissipation jacket 52 on the inner peripheral side is oil-tightly sealed by an O-ring 56 which is fitted and inserted in the ring of the flywheel main body 33 and the fin side annular plate member 35. The left end of the passage 45 and the upper end of the passage 48 are plugged together as shown.

Then, between the inner circumference of the lower boss portion 34 of the flywheel main body 33 and the outer circumference of the crankshaft upper shaft portion 8, a passage 57 is formed by a plurality of grooves along the axial direction in the fitting portion of both. Although the passage 57 is shown as a plurality of axial grooves formed on the outer periphery of the crankshaft upper shaft portion 8 in the figure, it may be formed on the inner periphery of the lower boss portion 34 of the flywheel main body. Alternatively, the passage 57 may be formed with a gap-shaped space continuous in the circumferential direction.

Further, the outer periphery of the lower boss portion 34 of the flywheel body and the bearing portion
Upper and lower oil seals 58, 58 are provided in the space formed between the inner circumference and the inner circumference of the 14 to form a passage 59 communicating with the passage 57.

The bearing portion 14 is formed with a passage 61 opening to the passage 59 and an axial passage 62 communicating with the passage 61. The right end portion of the passage 61 and the upper end portion of the passage 62 are plugged together as shown in the figure. Block. Further, a passage 63 is formed in the cylinder block portion 13 so as to open at the joint surface with the cylinder head 17, and the cooling holes 64, 66 are formed in the cylinder block portion 13 and the cylinder head 17 in the circumferential direction so as to open at the joint surface. Are formed respectively. A cooling jacket 65 is further formed on the cylinder head 17.

In addition, a passage 6 that communicates with the cooling jackets 64 and 66 and extends toward the oil pan 15 is formed in the lower wall of the cylinder block portion 13.
7, 68 and a passage 69 opening to the lower surface are formed. Further, the oil pan 15 is formed with a vertical passage 71 opening to the passage 69 and an inward passage 72. In the cooling jacket 64 of the cylinder head 17, a lubricating oil ejection port 73 is formed on the upper end side and an oil return port 74 is formed on the lower end side as shown in the figure.

According to the above oil passage structure, the lubricating oil O stored in the oil pan 15 passes through the cam shaft 21 and the crankcase portion 11 by the pump 25, and the crankshaft upper shaft portion 8
Heat dissipation jacket inside the flywheel 31
After passing through 52, it passes between the outer circumference of the crankshaft upper shaft portion 8 and the inner circumference of the bearing portion 14, and is fed into the cylinder block portion 13. Then, the oil flows through the cooling jackets 64, 65, 66 in the cylinder block portion 13 and the cylinder head 17 to cool the cylinder block portion 13 and the cylinder head 17.

Further, oil is supplied from the lubricating oil ejection port 73 to a valve operating mechanism (not shown) to lubricate each part, and the oil is returned from the cylinder block part 13 to the oil pan 15 together with the oil flowing from the oil return port 74, The oil circulation is performed as described above.

Therefore, the engine can be cooled by the lubricating oil, and the heat radiation jacket 52 in the rotating flywheel 31 can be used.
The oil can be cooled in the process of flowing.

Then, the two heat dissipation passages 51 and 54 including the heat dissipation jacket 52 in the flywheel 31 and the cooling passages 45 and 61 including the cooling jackets 64, 65 and 66 on the casing side (13, 17) are connected to each other. The structure is such that one is a connection passage 46, 47, 48, 49 passing through the inside of the crankshaft upper shaft portion 8 and the other is a connection passage through the fitting portion of the crankshaft upper shaft portion 8 and the flywheel 31. There are passages 57 and 59.

In this way, connect one of the connecting passages 46, 47, 48, 49 to the crankshaft 5
Since it is only formed inside, the passage structure inside the shaft can be simplified, and since the other connecting oil passages 57 and 59 are formed at the fitting portion of the crankshaft 5 and the flywheel 31, the inside passage is formed. In addition to the above processing, the processing of the entire connection passage can be facilitated.

When two connecting passages are formed in the crankshaft 5, three O-rings are provided in the fitting portion between the crankshaft 5 and the flywheel 31 in order to keep the two connecting passages oil-tight. In contrast to the case where it was necessary, in the case where only one connecting passage is formed in the crankshaft 5, two O-rings 55, 55 are used.
Since it is enough, the O-ring can be reduced.

Further, when two connecting passages are formed in the crankshaft, it is necessary to increase the shaft diameter from the viewpoint of strength, and the weight is increased. On the other hand, since only one connecting passage is formed in the crankshaft 5, The shaft diameter can be reduced to contribute to weight reduction.

Needless to say, the present invention is not limited to the engine model and model of the embodiment, but is applicable to other engine models and models. Further, the in-shaft passage and the outer passage may be formed in the opposite relationship to the embodiment with respect to the oil flow direction.

[Advantages of the Invention] As described above, according to the present invention, one of the two reciprocating connection passages connecting the casing-side cooling passage and the flywheel-side radiating oil passage is provided in the crankshaft. Since it is only formed, it is possible to achieve simplification of the passage structure in the shaft, and because the other connecting oil passage is formed in the fitting part between the crankshaft and the flywheel, processing of the passage in the shaft is possible. In addition, it is possible to achieve simplification of processing of the connection passage.

[Brief description of drawings]

The drawing is a vertical side view showing an engine as an example to which the present invention is applied. In the drawing, 5 is a crank shaft, 10 (11, 13) and 17 are casings, 21 is a cam shaft, 25 is an oil pump, 31 is a flywheel, and 46, 47, 48 and 49 are connection passages in the crank shaft. , 51,52,5
3,54 is a heat dissipation passage, 57,59 is a passage for connecting the crankshaft and the flywheel, 45,61,62,64,64,65,66,67.68,6
9 ... is a cooling passage.

Claims (1)

[Scope of utility model registration request] Claim: What is claimed is: 1. Lubricating oil is introduced into a cooling passage formed in a casing to cool the engine, and is also introduced into a heat dissipation passage formed in a flywheel provided at an end of a crankshaft protruding outward from the casing. An engine configured to also perform cooling, of the two connection passages for the forward path and the return path connecting the cooling passage and the heat dissipation passage, with one of the connection passages formed in the crankshaft, An engine cooling structure characterized in that the other connecting oil passage is formed in a fitting portion between the crankshaft and the flywheel.