JPS6336011A - Lubricating device for internal combustion engine - Google Patents

Abstract

PURPOSE:To enable an oil pump operatively interlocked with a crankshaft to be lubricated by supplying drain from a drain take-out port formed in a crank case to the position of a pair of gears meshing with each other of oil pump. CONSTITUTION:A drive gear 31 applied to a three-cylinder 2-cycle engine is integrally provided on the lower end of a crankshaft 1 disposed approximately vertically and meshes with a driven gear 33 integral with a rotary shaft 34 of an oil pump 32. And by the operation of oil pump 32 due to the rotation of crankshaft 1 is pressurized lubricating oil from an oil tank 50 and then sent forcibly from discharge ports 35a-35c to intake paths of respective cylinders. In this case a through hole 38 is formed adjacent a meshing position of both gears 31, 33 at the end side of rotary shaft 34. Also, a through hole 40 is formed coaxially with the through hole 38 in the crank case 3, and an oil path 24 for collecting drain on the wall surface of intake path 17 communicates to the hole 40 through a communicating path 42.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lubricating system for an internal combustion engine, and particularly to a lubricating system that operates an oil pump by rotation of a crankshaft, between a crankshaft and an oil pump. This invention relates to a lubrication structure for a power transmission mechanism.

[Prior Art] Internal combustion engines, particularly two-stroke engines for outboard motors, employ a split oil supply system in which lubricating oil is supplied to various parts of the engine using an oil pump, in addition to the system that supplies fuel to the engine. There are many things. The oil pump used in this Bunboku oil supply system has a driven gear meshed with a drive gear installed on the crankshaft.
It operates by rotating the crankshaft.

Here, as a transmission mechanism between the oil pump and the crankshaft, a ohmic gear or a helical gear is used.
These gears require constant lubrication due to their nature of high friction.

However, in the case of an extrauterine engine, since the engine body and the transmission compartment are separated, it is not appropriate to install the gear mechanism for driving the oil pump in the southeast transmission compartment. . Therefore, conventionally, the gear mechanism has been lubricated by using fuel oil containing 1 fJ oil extraction supplied into the crank chamber, and it has been difficult to obtain sufficient lubricating oil. Particularly, in the case of a structure in which a seal link is provided on the crankshaft to seal the crank chamber and the oil pump provided at the end of the crankshaft.

There is a fear that little lubricating oil is supplied to the power transmission mechanism between the crankshaft and the oil pump.

[Problems to be Solved by the Invention] The present invention has been made in view of the problems of the prior art, and its purpose is to provide a power transmission mechanism between the crankshaft and the oil pump. To provide a lubricating neck for an internal combustion engine that can supply sufficient lubricating oil without using a separate pump or the like.

[Means for solving the problem] In order to achieve this object, the present invention engages a driven gear of an oil pump with a drive gear provided on a crankshaft, and operates the oil pump by rotation of the crankshaft. In a lubrication system for an internal combustion engine, a communication passage is provided that communicates a drain outlet formed on the inner wall surface of the crankcase that houses the crankshaft with the meshing position d of the two gears, and the lubricating oil is mixed with the lubricating oil that is transmitted through the inner wall of the crankcase. The structure is such that the air drain can be supplied to the meshing necks of both gears.

[Operation] With this configuration, even if the crankshaft is provided with a seal link and the oil pump is sealed from the crank chamber in the crankcase, lubricating oil can be actively supplied to the gear mechanism that drives the oil pump. or will be supplied.

[Example] The present invention will be described below based on an example shown in the drawings. 1st
2 and 2 show an embodiment in which the present invention is applied to a 3-cylinder, 2-stroke engine with a minute oil supply system.

In Fig. 2, reference numeral 1 indicates a crankshaft for three cylinders arranged approximately vertically, 2 a cylinder block, and 3 a crankcase.
It is rotatably supported between the mating surfaces of the crankcase 3 and the crankcase 3. The crank/sleeve 1 is supported by four bearings, and the second car bearing 4 from the top and the third bearing 5 from the top are needle bearings, and the outer race 4a,
A suitable number of oil holes (not shown) are drilled in 5a. On the other hand, in order to hold the outer races 4a and 5a of the cylinder block 2 and the crankcase 3, an annular groove 7 is formed so as to connect the lubrication holes. Oil passages 8a and 8b are in communication. Oil passage 9a communicating with the lower part of each bearing 4.5
, 9b is provided in the cylinder tough port 2, and these oil passages 9a and 9b are connected to the scavenging passages 12a of the first and second cylinders, which will be described later.
, 12b, respectively.

10a, iob, and 10c are the first and second from the L side, respectively.
, a piston forming the third air shaft, and the connecting rod 11
to the crankshaft l]! I! tied together. Each cylinder is configured to have a crank rotation angle of 120 degrees, and the first cylinder at the top of Fig. 2 is at the top dead center position, and the second cylinder in the middle is at 1δ at 60 degrees before the bottom dead center. Also, the third one at the bottom
This shows a state where the cylinder is at about 60 degrees after bottom dead center.

Note that arrow A in FIG. 2 indicates the rotation direction of the crankshaft 1. Scavenging passages 12a, 12b, and 12c are formed in the cylinder block 2 to correspond to each cylinder. 13 is a cylinder head, 14 is a cylinder head, and 15 is a spark plug.

An intake passage 17 opens into a crank chamber 16 formed by the crank case 3 and cylinder block 2.

This intake passage 17 is an intake pipe 1 integrated with the crankcase 3.
A valve holding frame 19 inserted into the intake pipe 18 from the carburetor 21 side, which will be described later, and a reed valve 20 held in the valve holding frame 19 are formed in the intake passage 17 by the valve holding frame 19.
or the like is provided to only allow intake air to flow into the crank chamber 16 and prevent its reverse flow. A carburetor 21 is connected to the intake passage 17 of each cylinder. This z converter 21 generates a mixture of fuel and air, and lubricating oil from an oil pump, which will be described later, is mixed into this mixture. Note that the intake passage 17 is connected to its carburetor 21 (11
The crank chamber 16 side is formed to be higher than the crank chamber 16 side, so that intake air containing the air-fuel mixture and lubricating oil can smoothly flow into the crank chamber 16.

The lower end of the crankshaft 1 is sealed against the cylinder block 2 and crankcase 3 by a seal link 30, thereby sealing the crank chamber 16 from the outside. As shown in more detail in FIG.

A drive gear 31 corresponding to the ohm of the ohm gear mechanism is integrally provided on the shaft portion below the seal ring 30, and the drive gear 31 is equipped with a well-known oil pump 32.
The driven gear 33 is integrally provided with the rotating shaft 34 of the rotary shaft 34, and is meshed with the driven gear 33 as an ohm wheel. The oil pump 32 is operated by receiving rotational power from the crankshaft 1 via the ohmic gear mechanism, receives lubricating oil from an oil tank 50 arranged above the carburetor 21, and has a discharge port 35a corresponding to the number of cylinders. , 35b, and 35C, the n1 lubricating oil is force-fed to the intake passage of each cylinder.

Here, is the end of the rotating shaft 34 of this oil pump 32 rotatably supported by a bush 36 with respect to the crankcase 3, or is there a space between this bush 36 and the end of the rotating shaft 34? In addition, a unique configuration is provided for the lubrication of the ohmic gear mechanism. That is,
A through hole 38 is bored from the leading end of the rotating shaft 34 of the oil pump 32 along its axis, and this through hole 38 opens at the tooth surface of the driven gear 33, that is, at the f1 matching position of both gears. . In addition, a through hole 40 is bored in the crankcase 3 that supports the end of the rotating shaft 34 so as to be substantially the same as the through hole 38. It communicates with the oil passage 24 to be collected, that is, with the drain outlet. Therefore, 1 car through hole 3 days, 40
A lubricating oil or a drain of the mixed air mixture is introduced into the oil pump 30, so that not only the ohmic gear mechanism but also the space between the rotating shaft 34 of the oil pump 32 and the bushing 36 is lubricated.

In the intake passages 17 of the first and second cylinders, a substantially horizontal flat portion is formed at a portion where the lower wall surface of the crank chamber 16 and the inner wall surface of the crank chamber 16 are connected, and the crankshaft rotation of this flat portion is formed. A collection groove 23 for drain, which is a wall flow, is formed at a position closer to the direction (the direction of the arrow). This collection groove 23 communicates with an oil passage 24 as a drain outlet formed in a metal fitting screwed onto the crankcase 3.

As shown in FIG. 2, the oil passage 24 of the first cylinder is connected to the third cylinder.
It communicates with an oil passage 8b provided in the bearing 5 via a check valve 25, and this communication passage branches as shown at 42 and is connected to a through hole 40 of the crankcase 3. The oil passage 24 of the second cylinder communicates with the oil passage 8a provided in the second bearing 4 via a check valve 26. The check valves 25 and 26 respectively allow flow only in the direction of each bearing 4.5 from the collecting groove 23 of each cylinder. In FIG. 2, 27 indicates an exhaust boat.

Next, the operation of this embodiment will be explained. When the crankshaft 1 rotates in the direction of the arrow, the drive gear 31 and driven gear 33 (
The oil pump 32 is operated via the first engine, and the lubricating oil from the oil tank 50 is pumped into the intake passage 17 of each cylinder, where the lubricating oil is mixed into the air-fuel mixture from the carburetor 21. In the cylinder in the suction stroke, this mixture and lubricating oil are sucked into the crank chamber 16. During this intake stroke, a portion of the fuel and lubricating oil adheres to the inner wall surface of the intake passage [7] and becomes a drain, that is, a wall flow, to the crank chamber 16.
flow inside. The wall flow flows through the intake passage 17 due to its own weight.
A lot of it flows on the lower wall. This wall flow flows into the crank chamber 16 through a flat portion formed between the intake passage 17 and the crank chamber 16. This flat part has a wall flow collection groove 23.
Since a portion of the wall flow flowing in from the lower wall surface of the intake passage 17 is collected in the wall flow collecting groove 23. However, since the collection groove 23 does not completely cross the intake passage 17, a portion of the wall flow directly enters the crank chamber 16 and is used to lubricate the large end of the connecting rod 11, etc.

The intake stroke is also a compression stroke, and the intake air compressed in the combustion chamber is ignited by the spark plug 5 and exploded. In this explosion stroke, the internal pressure of the crank chamber 16 increases. At the end of the explosion stroke, the pistons lOa, 10b, 10c
opens the exhaust boat 27, and at the same time as exhaust begins, the scavenging boats of the scavenging passages 12a, 12b, and 12c also begin to open.

Therefore, the precompressed intake air in the crank chamber 16 flows into the combustion chamber through the scavenging passages L2a, 12b, and 12c, and scavenges the burned gas.

Since the rotational positions of the first cylinder and the second 'A cylinder are shifted from each other, when one crank chamber 16 has positive pressure, the other crank chamber 16 has negative pressure. The wall flow collected in the collecting groove 23 by this differential pressure is sent to the crankshaft bearing 4.5 of the other cylinder. That is, considering the case where the crankshaft l continues to rotate from the 21st Z state, when the piston 10a passes the top dead center, the internal pressure of the crank chamber 16 of the first cylinder increases, while the scavenging boat opens in the second cylinder. Scavenging passage 12b
Since the intake air enters the combustion chamber through the combustion chamber, the internal pressure of the crank chamber 16 of this second cylinder decreases. Due to the pressure difference in the crank chamber 16 of each cylinder, a wall flow containing lubricating oil flows from the collecting groove 23 of the first cylinder through the check valve 25, the oil passage 8b, and the annular groove 7 into the third bearing 5. , lubricate this.

At the same time, the wall flow is actively introduced into the through hole 40 of the crankcase 3 through the communication path 42, and the oil pump 32
It lubricates between the rotating shaft 34 and the bushing 36, and also lubricates between the drive gear 31 of the crankshaft l and the driven gear 33 of the rotating shaft 34 through the through hole 38 of the rotating shaft 34.

The lubricating oil that has lubricated the third bearing 5 gradually flows out to the scavenging passage 12b of the second cylinder via the oil passage 9b. Conversely, when the internal pressure of the crank chamber 16 of the second cylinder increases, the wall flow passes through the second bearing 4 from the collection groove 23 of the second cylinder and gradually flows out into the scavenging passage 12a of the first cylinder.

As described above, according to this embodiment, when the drain of the mixture containing lubricating oil is actively supplied to each bearing portion by utilizing the differential pressure in the crank chamber 16 between each cylinder, the drain is Since the communication path is branched midway and supplied to the gear mechanism of the crankshaft l and the oil pump 32 to lubricate them, there is no need for a separate pump or other means for pumping lubricating oil. Further, according to the present embodiment, a through hole 38 is formed from the end of the rotating shaft 34 of the oil pump 32, and the through hole 38 is opened to the south face of the gear, and the crank case 38 supports the end of the rotating shaft 34. A through hole 40 communicating with the through hole 38 also communicates with the through hole 38.
Since this is formed, lubrication between the rotary shaft 34 and the shaft 36 that rotatably supports it can be performed at the same time, and there is no need for special extremely complicated piping for this lubrication.

[Effects] As described above, according to the present invention, lubricating oil can be actively supplied to the oil pump and the power transmission mechanism of the crankshaft without providing a separate means for pumping lubricating oil such as a pump, thereby providing smooth operation. This has the excellent effect of ensuring proper oil pump operation.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a lubricating device for an internal combustion engine according to the present invention, and FIG. 2 is a cross-sectional view of FIG. 1. l...Crankshaft 3...Crank case 31...Drive gear 32...Oil pump 33...Driven gear 42...Communication path

Claims (1)

[Claims] (1) In a lubricating system for an internal combustion engine in which a driven gear of an oil pump is engaged with a drive gear provided on the crankshaft, and the oil pump is operated by rotation of the crankshaft,
A communication path is provided that communicates the drain outlet formed on the inner wall surface of the crankcase that houses the crankshaft with the meshing position of the two gears, and the drain of the lubricating oil and air-fuel mixture transmitted through the inner wall of the crankcase is connected to the meshing position of the two gears. A lubricating device for an internal combustion engine that can be supplied to any position.