JPS6049120A - Bearing structure of internal-combustion engine for vessel propelling machine - Google Patents

Abstract

PURPOSE:To prevent the generation of damage of a bearing part, etc. due to the foreign material in the lubricating oil stored into an oil groove by forming the oil groove onto the inner peripheral surface of the bearing part and opening a lubricating-oil passage into the oil groove, in the bearing part for a rotary shaft which is formed onto an engine body. CONSTITUTION:When an internal-combustion engine 16 is in revolution and a lubricating-oil pump 37 is driven through a cam shaft 36 by the revolution of a crankshaft 29, the lubricating oil in an oil pan 51 is sent under pressure into a lower oil-passage 54 and an upper oil-passage 55. In this case, an annular oil groove 64 is formed onto a part of the inner peripheral surface of the bearing part 63 of a cylinder head 22 which supports the cam shaft 36, and the upper oil-passage 55 is opened to the oil groove 64. Therefore, the lubricating oil sent under pressure into the upper oil-passage 55 is supplied onto the whole periphery of the bearing part 63 through the oil groove 64. In this case, the foreign material mixed into the lubricating oil is pushed into the innermost part of the oil groove 64 by the centrifugal force due to the accompanied revolution onto the cam shaft 36. Therefore, the intrusion of the foreign material onto the supporting surface 63A side of the bearing part 63 can be prevented, and an aimed purpose can be achieved.

Description

[Detailed description of the invention] The present invention relates to a bearing structure for an internal combustion engine for a marine vessel propulsion device.

In internal combustion engines such as outboard motors, a rotating shaft such as a camshaft or a crankshaft is supported by a bearing formed in the engine body itself, and a system that enables smooth supply of lubricating oil to the bearing is required. (A bearing structure is used in which an annular oil groove is formed in a part of the front side of the rotating shaft, and a lubricating oil passage provided in the engine body is opened toward the oil groove.

However, in the above-mentioned conventional bearing structure, dirt, abrasion particles, etc. mixed in the lubricating oil sent into the oil groove accumulate in the oil groove, and as a result, centrifugal force generated by rotation with the rotating shaft occurs. , and under the action of the pumping force of the lubricating oil, the lubricating oil may enter the sliding contact area between the rotating shaft and the support surface of the bearing, causing damage such as galling to the rotating shaft and the bearing.

SUMMARY OF THE INVENTION An object of the present invention is to prevent damage to a bearing portion and a rotating shaft caused by dirt, abrasion powder, etc. that accumulate in an oil groove.

In order to achieve the above object, the present invention provides a bearing structure for an internal combustion engine for a marine propulsion machine in which a bearing part capable of supporting a rotating shaft is formed in the engine body itself, and in which the inner circumferential surface of the bearing part is An annular oil groove is formed in a part of the engine, and a lubricating oil passage provided in the engine body opens into the oil groove.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a side view showing an outboard motor to which an embodiment of the present invention is applied, and FIG. 2 is a sectional view showing an internal combustion engine of the outboard motor.
3 is a cross-sectional view showing the main part of FIG. 2, and FIG. 4 is a cross-sectional view showing the main part of FIG. 3 in an enlarged manner.

A casing 14 is supported on a stern plate 11 of the hull via a ramp bracket 12 and a swivel bracket 13. At the top of the casing 14.

An internal combustion engine 16 is mounted via a plate-shaped intermediate member 15. The output of the internal combustion engine 16 is transmitted to the propeller 19 via a drive shaft 17 vertically disposed within the casing 14 and a forward/reverse switching mechanism 18, allowing the propeller 19 to rotate forward or backward.

As shown in FIGS. 2 and 3, the internal combustion engine 16 is a water-cooled four-stroke two-cylinder internal combustion engine, and its main body is formed by a cylinder case 20, a crankcase 21, a cylinder head 22, and a head cover 23. . A pair of upper and lower cylinders are arranged horizontally in the cylinder case 20, and a piston 24 is disposed in each cylinder so as to be able to reciprocate in the horizontal direction.

A space defined by the cylinder case 20 and the cylinder head 22 on the top surface side of the piston 240 is a combustion chamber 25 . A spark plug, an intake port opened by an intake valve, and an exhaust boat opened by an exhaust valve are arranged in a portion of the cylinder head 22 facing the combustion chamber 25.

In addition, the cylinder case 20 and the crank case 2
A space defined by 1 on the back side of the piston 24 is defined as a crank chamber 28. A crankshaft 29 supported by a bearing formed at the mating surface of the cylinder case 20 and the crankcase 21 is vertically disposed in the crank chamber 28, and the lower end of the crankshaft 29 is connected to the upper end of the drive shaft 17. are connected. The crankshaft 29 has a crank pin 31 between its webs 30, to which a large end 33 of a connecting rod 32 is connected. The small end of the connecting rod 32 is connected to the piston 24 by a piston pin. That is, the crankshaft 29 rotates according to the reciprocating motion of the piston 24 based on the explosive force within the combustion chamber 25, and is capable of applying rotational force to the drive shaft 17.

The space defined by the cylinder spatula 22 and the head cover 23 is a cam chamber 35. A camshaft 36 is placed vertically in the cam chamber 35, and the upper end of the camshaft 36 is directly supported by a bearing portion 63 formed on the cylinder head 22 itself, as will be described later, and the lower end thereof is supported by a lubrication system, which will be described later. The housing 387 of the oil pump 37 serves as a valve and is indirectly supported by the cylinder head 22. An intake cam 39 and an exhaust cam 40 are formed on the camshaft 36. Intake cam 3
9 and the exhaust cam 40 enable the intake valve and the exhaust valve to be opened via each rocker arm 42 supported by each rocker shaft. In addition, the camshaft 36
A driven wheel 43 is fixed to the upper end of the crankshaft 29 that protrudes from the cam chamber 35 , and a driving wheel 44 is fixed to the upper end of the crankshaft 29 that projects from the crank chamber 28 .
A belt 45 is wound around the drive wheel 44, and the camshaft 36 can be driven by 290 rotations of the crankshaft.

On the lower surface of the cylinder head 22, the housing 38 of the lubricating oil pump 37 is fixedly arranged coaxially with the camshaft 36 as described above. A pump chamber 46 is formed in the lubricating oil pump 37 , and an impeller 48 that is integrated with a connecting shaft 47 that hangs down from the lower end of the camshaft 36 is disposed in the pump chamber 46 . ,I? A suction passage 49 is opened at the lower part of the intake chamber 46, and a discharge passage 50 is opened at the upper part thereof.

An oil nozzle ξ hole 51 is fixed to the lower surface of the intermediate member 150 substantially at the central shaft. Suction path 4 of the above-mentioned Junyu oil Ponzo 3T
9 is an oil passage 52 formed in the cylinder head 22 and the cylinder case 20, which communicates with the oil passage 52 and connects the intermediate member 1.
The oil pan 5
It is said that it is possible to communicate with the lubricating oil of 1. That is, when the internal combustion engine 16 is operating, the lubricating oil pump 37 is driven together with the rotation of the camshaft 360, so that the lubricating oil in the oil nozzle 51 can be pumped to the discharge passage 50 side.

The lubricating oil pumped by the lubricating oil pump 3γ is sent from a discharge passage 50 to a lower oil passage 54 formed toward the crankshaft 29 on the lower surface side of the cylinder head 22 and cylinder case 20, and Oil is supplied to an upper oil passage 55 formed on the upper surface side of the cylinder head 22 and cylinder case 20 in a direction connecting the crankshaft 29 and the camshaft 36. Note that the lower oil passage 54 and the upper oil passage 55 are communicated with each other by a communication oil passage (not shown) that branches from an intermediate portion of the lower oil passage 54 and extends vertically on the side surface of the cylinder case 20.

The lubricating oil sent to the lower oil passage 54 is transmitted to the crankshaft 29
The oil is supplied to the bearing portion sealed by an oil seal 56 at the lower end side of the crankshaft 29 to lubricate the bearing portion, and is supplied to the large end of the crank bin 31 and the connecting rod 32 via an oil passage 58 bored in the crankshaft 29. After lubricating the big end bearing part formed with the part 33, it is scattered into the crank chamber 28. Further, the lubricating oil flowing toward the crankshaft 29 side of the upper oil passage 55 is supplied to the bearing portion sealed by the oil seal 59 on the upper end side of the crankshaft 29, and lubricates the bearing portion and also lubricates the bearing portion. After lubricating the big end bearing formed by the crank bottle 31 and the big end 33 of the connecting rod 32 through the oil passage 61 bored in the crankshaft 29, the crank chamber 28
Scattered. The lubricating oil scattered in the crank chamber 28 as described above moves downward in the crank chamber 28 and returns to the oil pan 51 through the return oil passage 62 formed by the cylinder case 20 and the intermediate member 15. It looks like this.

Here, in this embodiment, as described above, the camshaft 3
An annular oil groove 64 is formed in a part of the inner peripheral surface of the bearing part 63 of the cylinder head 22 that directly supports the cylinder head 6, and the upper oil passage 55 is opened into the oil groove 64. Namely, Shangyou Road,
The lubricating oil flowing from 55 to the camshaft 36 is smoothly supplied to the bearing portion 63 sealed by the oil seal 65 through the oil groove 64, and then flows downward along the outer peripheral surface of the camshaft 36. The cam surfaces of the intake cam 39 and exhaust cam 40 are lubricated. After lubricating the camshaft 36, the lubricating oil moves downward in the cam chamber 35 and returns to the oil pan 51 through the return oil passage 66 formed in the cylinder case 20 and the cylinder head 22. ing. Note that the oil groove 64 is set at a position below the axial center position (indicated by line CC in FIG. 4) of the support surface 63A of the bearing portion 63.

Next, the operation of the above embodiment will be explained.

When the internal combustion engine 16 is operating, the crankshaft rotates 290 times,
When the lubricating oil bonder 37 is driven via the camshaft 36,
The lubricating oil in the ann 51 is sent to the lower oil passage 54 and the upper oil passage 55 by driving the lubricating oil bonder 37 . The lubricating oil that is forced into the upper oil passage 55 and directed toward the camshaft 36 passes through the oil groove 64 and is smoothly supplied to the entire circumference of the bearing portion 63, and then falls downward along the outer peripheral surface of the camshaft 36. , the cam surfaces of the intake cam 39 and exhaust cam 40 are lubricated, and the return oil path 6
6 and returns to the oil seal 51.

Therefore, in this embodiment, dirt, abrasion powder, etc. mixed in the lubricating oil fed into the oil groove 64 are removed from the camshaft 64.
Based on the rotation toward G (the centrifugal force pushes the oil deep into the oil groove 64 and prevents it from entering the support surface 63A side of the bearing 63), damage such as galling to the camshaft 36 and the bearing 63 is prevented. will not occur.

In addition, in this example, as shown in FIG.
Since the oil groove 64 is set at a lower position on the support surface 63A of the bearing part 63 (7:l), some of the dirt, abrasion powder, etc. pushed into the oil groove 64 is pushed to the support surface 63A side due to the influence of gravity. Even if the camshaft 36 and the bearing part 63 are dropped, the falling debris, abrasion powder, etc. only pass through a relatively narrow range on the lower end side of the support surface 63A, making it possible to more reliably prevent damage to the camshaft 36 and the bearing part 63. do.

The oil groove 64A in the present invention may have a triangular cross-sectional shape that gradually widens downward, as shown in FIG. f 7j, the oil groove 64B may have a stepped groove cross-sectional shape with an expanded portion at the bottom, as shown in FIG.

According to the oil grooves 64A and 64B, dirt, abrasion particles, etc. mixed in the lubricating oil are stably pushed deep into the lubricating oil under the action of centrifugal force and gravity.

The possibility of falling onto the support surface 63A side can be more reliably eliminated.

Note that in the above embodiment, the camshaft 36 is supported by the camshaft 111.
Description of the case where the present invention is applied to a single bearing structure The present invention can be similarly applied to a bearing structure in which another rotating shaft such as a crankshaft is a supporting nail.

Further, in the above embodiments, the present invention is applied to a bearing structure in which the rotating shaft is vertically arranged.

The present invention is also applicable to a bearing structure in which the rotating shaft is placed horizontally.

As described above, the present invention provides a bearing structure for an internal combustion engine for a marine propulsion engine in which a bearing part capable of supporting a rotating shaft is formed in the engine body itself, in which a part of the inner circumferential surface of the bearing part has an annular shape. An oil groove is formed in the engine body, and one lubricating oil supply passage is opened into the oil groove. Therefore, dirt mixed in the lubricating oil sent into the oil groove,
Abrasion particles, etc. are pushed into the deep part of the oil groove by the long ru force based on the co-rotation of the rotating shaft, and do not enter the rotating shaft support surface of the bearing. No damage will occur.

[Brief explanation of drawings]

FIG. 1 is a side view showing an outboard motor to which an embodiment of the present invention is applied, and FIG. 2 is a sectional view showing an internal combustion engine of the outboard motor.
Figure 3 is a cross-sectional view showing the main part of Figure 2, Figure 4 is a cross-sectional view showing the main part of Figure 3 in an enlarged manner, and Figures 5 and 6 are
Each figure is a sectional view showing a modification of the present invention. 22... Cylinder head, 36... Camshaft -55.
... Upper front road, 63... Bearing part, 64, 64A, 64B
...Oil groove. Agent Patent Attorney Osamu Shiokawa

Claims (1)

[Claims] (1) In a bearing structure for an internal combustion engine for a marine propulsion engine in which a bearing part capable of supporting a rotating shaft is formed in the engine body itself, an annular oil groove is formed in a part of the inner peripheral surface of the first part of the bearing. 5. A bearing structure for an internal combustion engine for a marine propulsion device, characterized in that a lubricating oil feed path provided in the engine body opens into the oil groove.