JPH0696970B2 - Lubricating device for internal combustion engine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating device for an internal combustion engine, and more particularly, it relates to a lubricating device for an internal combustion engine, in which the oil pump is operated by rotation of the crankshaft. The present invention relates to a lubricating structure for a power transmission mechanism.

[Prior Art] In an internal combustion engine, in particular, for example, a two-cycle engine for an outboard motor, a separate oil supply system in which a lubricating oil is supplied to each part of the engine by an oil pump is adopted in addition to a system for supplying fuel to the engine. There are many. The oil pump used in this separate oil supply method is such that a driven gear of the oil pump is engaged with a drive gear provided on a crankshaft,
It is designed to operate by rotating the crankshaft.
Here, a worm gear or a screw gear is used as a gear transmission mechanism between the oil pump and the crankshaft, and since these gears have large friction due to their properties, sufficient lubrication is required. However, in the outboard motor, since the engine body and the transmission gear chamber are separated from each other, it is not appropriate to install the gear mechanism for driving the oil pump in the transmission gear chamber. Therefore,
Conventionally, the gear mechanism has been lubricated by using fuel oil containing lubricating oil supplied into the crank chamber, and it has been difficult to obtain sufficient lubricating oil. Particularly, in a structure in which a crank ring is provided with a seal ring to seal the crank chamber and an oil pump provided at the end of the crank shaft, most of the lubricating oil is supplied to the power transmission mechanism between the crank shaft and the oil pump. There is a fear that it will not be done.

[Problems to be Solved by the Invention]

According to the present invention, the crankshaft is arranged substantially vertically and the cylinders in the cylinder block are arranged substantially horizontally, the lower end of the crankshaft is sealed by a sealing member to seal the crank chamber, and the gear below the sealing member is sealed. In a lubricating device for an internal combustion engine in which a driving gear and a driven gear are housed in a chamber, a power transmission mechanism between a crankshaft / driving gear and a driven gear is provided.
The challenge is to supply sufficient lubricating oil without using a separate pump or the like.

[Means for Solving the Problems]

In order to solve the above-mentioned problems, the present invention meshes a driven gear of an oil pump with a drive gear provided on a crankshaft, arranges the crankshaft substantially vertically, and makes a cylinder in a cylinder block substantially horizontal. Placed in the crank chamber formed by the crankcase and cylinder block,
The intake passage extending in the direction opposite to the cylinder is connected, and a reed valve that allows only intake to the crank chamber is provided in the intake passage.The lower end of the crankshaft is sealed by a seal member to seal the crank chamber In a lubricating device of an internal combustion engine, the drive gear and the driven gear are housed in a gear chamber below a member, and an oil pump is operated by rotation of a crankshaft to supply oil to the intake passage. An oil outlet is opened in the lower wall surface of the passage, and the oil outlet is communicated with the gear chamber through the communication passage.

[Action]

The air-fuel mixture flows from the carburetor into the intake passage, passes through a reed valve that allows only intake to the crank chamber provided in the intake passage, and then flows into the crank chamber formed by the crankcase and the cylinder block. An oil outlet opening on the lower wall surface of the intake passage downstream from the reed valve collects the wall surface flow containing lubricating oil (oil), and the lubricating oil flows through the communication passage to the gear chamber, which drives the gear chamber. Lubricate gears and driven gears.

[Examples] The present invention will be described below based on Examples shown in the drawings. First
FIG. 2 and FIG. 2 show an embodiment in which the present invention is applied to a three-cylinder two-cycle engine of a separated oil supply system.

In FIG. 2, reference numeral 1 is a crankshaft for three cylinders arranged substantially vertically, 2 is a cylinder block, and 3 is a crankcase. Crankshaft 1 is these cylinder blocks 2
Is rotatably supported between mating surfaces of the crankcase 3 and the crankcase 3, and the cylinders in the cylinder block 2 are arranged substantially horizontally. The crankshaft 1 is rotatably supported by four bearings, and the second second bearing 4 and the third third bearing 5 from the top are needle bearings, and their outer races 4a,
An appropriate number of oiling holes (not shown) are drilled in 5a.
On the other hand, on the surfaces of the cylinder block 2 and the crankcase 3 that hold the outer races 4a, 5a, an annular groove 7 is formed so as to connect the lubrication holes, and the annular groove 7 is formed in the crankcase 3. The oil passages 8a and 8b communicate with each other. Oil passages 9a and 9b communicating with the lower portions of the bearings 4 and 5 are provided in the cylinder block 2, and these oil passages 9a and 9b are communicated with scavenging passages 12a and 12b of the first and second cylinders, respectively, which will be described later.

Reference numerals 10a, 10b, and 10c denote pistons that form first, second, and third cylinders from above, and are connected to the crankshaft 1 by a connecting rod 11. Each cylinder is configured to have a crank rotation angle of 120 °. The first cylinder in the upper part of Fig. 2 is at the top dead center position, the second cylinder in the middle is at the 60 ° position before bottom dead center, and the lower part is in the lower part. No. 3 cylinder is located at 60 ° after bottom dead center. The arrow A in FIG. 2 indicates the rotation direction of the crankshaft 1. Scavenging passages 12a, 12b, 12c are formed in the cylinder block 2 corresponding to each cylinder. Reference numeral 13 is a cylinder head, 14 is a cylinder head cover, and 15 is a spark plug.

An intake passage 17 extending in a direction opposite to the cylinder is opened in a crank chamber 16 formed by the crankcase 3 and the cylinder block 2. The intake passage 17 is formed by an intake pipe 18 that is integral with the crankcase 3. The intake passage 17 has a valve holding frame 19 inserted into the intake pipe 18 from a carburetor 21 side described later, and the valve holding frame 19. The retained reed valve 20 is provided to allow only the intake air to flow into the crank chamber 16 and prevent its backflow. A carburetor 21 is connected to the intake passage 17 of each cylinder. The carburetor 21 generates a mixture of fuel and air, and the mixture is mixed with lubricating oil from an oil pump described later. The intake passage 17 is formed so that its carburetor 21 side is higher than its crank chamber 16 side, and smoothes the flow of the intake air made of the air-fuel mixture and lubricating oil into the crank chamber 16.

The lower end of the crankshaft 1 is sealed to the cylinder block 2 and the crankcase 3 by a seal ring 30 to seal the crank chamber 16 from the outside. As shown in more detail in FIG. 1, a drive gear 31 corresponding to a worm of a worm gear mechanism is integrally provided on a shaft portion below the seal ring 30, and the drive gear 31 has a known oil pump 32. Driven gear integrally provided on the rotary shaft 34 of
33 is meshed as a worm wheel. In this way, the gear chamber (the lower chamber of the seal ring 30 in FIG. 2) accommodating the rotary shaft 38, the drive gear 31, and the driven gear 33 is made into the crank chamber 16 by the seal ring 30, that is, the seal member.
It is sealed and partitioned against. This oil pump
32 is operated by receiving rotational power from the crankshaft 1 via the worm gear mechanism, receives lubricating oil from an oil tank 50 arranged above the carburetor 21, and discharge ports 35a, 35b, 35c corresponding to the number of cylinders. To pump the lubricating oil to the intake passage of each cylinder.

Here, the end of the rotary shaft 34 of the oil pump 32 is rotatably supported by the bush 36 with respect to the crankcase 3. A unique construction is provided for lubrication of the worm gear mechanism. That is, the oil pump 32
A through hole 38 is bored from the tip of the rotary shaft 34 along the axis of the rotary shaft 34, and the through hole 38 opens at the gear of the driven gear 33, that is, at the meshing position of both gears. The crankcase 3 supporting the end of the rotary shaft 34 is also provided with a through hole 40 substantially coaxially with the through hole 38. The through hole 40 supplements a drain on the wall surface of the intake passage 17, which will be described later. It is connected to the collecting oil passage 24, that is, the drain outlet (oil outlet). Therefore, the drain of the air-fuel mixture in which the lubricating oil is mixed is introduced into both the through holes 38 and 40 so that not only the worm gear mechanism but also the rotating shaft 34 of the oil pump 32 and the bush 36 are lubricated. Has become.

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

As shown in FIG. 2, the oil passage 24 of the first cylinder communicates with the oil passage 8b provided in the third bearing 5 via a check valve 25, and this communication passage branches as indicated by reference numeral 42. And is connected to the 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 only the flow from the collecting groove 23 of each cylinder toward the bearings 4 and 5. In Figure 2
27 indicates an exhaust port.

Next, the operation of this embodiment will be described. When the crankshaft 1 rotates in the direction of arrow A, the oil pump 32 operates via the meshing of the drive gear 31 and the driven gear 33, and the lubricating oil from the oil tank 50 is pumped into the intake passage 17 of each cylinder. The lubricating oil is mixed into the mixture from the vaporizer 21. In the cylinder on the intake stroke, this mixture and lubricating oil
Inhaled into 16 In this intake stroke, a part of the fuel and the lubricating oil adheres to the inner wall surface of the intake passage 17 and flows into the crank chamber 16 as a drain, that is, a wall surface flow. A large amount of wall flow flows to the lower wall of the intake passage 17 due to its own weight.
This wall surface flow flows into the crank chamber 16 through the flat portion formed between the intake passage 17 and the crank chamber 16. Since the wall surface flow collecting groove 23 is formed in this flat portion, the intake passage
A part of the wall surface flow that flows in from the lower wall surface of 17 is collected in the wall surface collection groove 23. However, since the collecting groove 23 does not traverse the entire intake passage 17, a part of the wall surface flow enters the crank chamber 16 as it is and is used for lubricating the large end portion of the connecting rod 11 and the like.

The intake stroke is also a compression stroke at the same time, and the intake air compressed in the combustion chamber explodes due to ignition by the spark plug 5. In this explosion stroke, the internal pressure of the crank chamber 16 rises. At the end of the explosion stroke, the pistons 10a, 10b, 10c open the exhaust port 27, and at the same time as the exhaust starts, the scavenging passages 12a, 12b,
The 12c scavenging port also begins to open. Therefore, the pre-compressed intake air in the crank chamber 16 flows into the combustion chamber through the scavenging passages 12a, 12b, 12c, and scavenges the burned gas.

Since the rotational positions of the first cylinder and the second cylinder are deviated from each other, when one crank chamber 16 has a positive pressure, the other crank chamber 16 has a positive pressure.
16 becomes negative pressure. The wall surface flow collected in the collection groove 23 by this pressure difference is sent to the crankshaft bearings 4 and 5 of the other cylinders. That is, considering the case where the crankshaft 1 further rotates from the state shown in FIG. 2, when the Biston 10a passes the top dead center, the internal pressure of the crank chamber 16 of the first cylinder rises, while the scavenging port of the second cylinder is Since the intake air enters the combustion chamber through the open scavenging passage 12b, the internal pressure of the crank chamber 16 of the second cylinder decreases. Due to the pressure difference in the crank chamber 16 of each cylinder, the wall surface flow containing the lubricating oil from the collecting groove 23 of the first cylinder flows into the third bearing 5 through the check valve 25, the oil passage 8b, and the annular groove 7. , Lubricate this. At the same time, the wall surface flow is positively introduced into the through hole 40 of the crankcase 3 through the communication passage 42 to lubricate the space between the rotary shaft 34 and the push 36 of the oil pump 32, and the through hole 38 of the rotary shaft 34. The drive gear 31 of the crankshaft 1 and the driven gear 33 of the rotary shaft 34 are lubricated through the shaft. The lubricating oil that lubricated the third bearing 5 gradually flows out to the scavenging passage 12b of the second cylinder via the oil passage 9b. On the contrary, when the internal pressure of the crank chamber 16 of the second cylinder rises, the wall surface flow gradually flows from the collecting groove 23 of the second cylinder through the second bearing 4 to the scavenging passage 12a of the first cylinder.

Thus, according to this embodiment, the crank chambers between the cylinders are
When the drain of the air-fuel mixture containing lubricating oil is positively supplied to each bearing part by utilizing the differential pressure of 16, the communication passage of the drain is branched midway and the gears of the crankshaft 1 and the oil pump 32 are divided. Since it is supplied to the mechanism and lubricated, no separate means for pumping the lubricating oil such as a pump is required. Further, according to the present embodiment, the crankcase 3 that forms the through hole 38 from the end of the rotary shaft 34 of the oil pump 32, opens the through hole 38 in the tooth surface of the gear, and supports the end of the rotary shaft 34. Since the through hole 40 communicating with the through hole 38 is also formed, lubrication between the rotary shaft 34 and the bush 36 rotatably supporting the rotary shaft 34 can be performed at the same time, and special extremely complicated lubrication is required for these lubrication. No piping is required.

[Effect] In the present invention, the crankshaft is arranged substantially vertically and the cylinders in the cylinder block are arranged substantially horizontally, and the lower end of the crankshaft is sealed by the seal member to seal the crank chamber, The drive gear and the driven gear are housed in the lower gear chamber, a wall surface flow collecting groove is formed on the lower wall surface of the intake passage downstream of the reed valve, and the wall surface flow collecting groove is communicated with the gear chamber by the communication passage. It was Therefore, the intake passage is at a position higher than the gear chamber, and the lubricating oil in the wall surface flow collected by the wall surface collecting groove naturally falls due to gravity, and the lubricating oil passes through the communication passage and the gear. Can be smoothly supplied to the room. Further, the difference between the pressure in the intake passage downstream of the reed valve and the pressure in the gear chamber promotes the flow of the lubricating oil from the wall surface flow collection groove to the gear chamber. In this way
Without using a separate pump, etc. for the power transmission mechanism between the crankshaft in the gear chamber, the drive gear and the driven gear,
Sufficient lubricating oil can be supplied.

In the conventional engine of the outboard motor, the direction of intake air flowing from the intake passage into the crank chamber and the direction of extension of the cylinder from the crank chamber are the same, so the crank chamber runs along the lower wall of the intake passage. The oil that flows into the cylinder flows as it is toward the cylinder due to the intake air flow, and then flows into the combustion chamber through the scavenging port, the gap between the piston and the cylinder, and the like, causing a problem such as white smoke. However, in the present invention, since the oil outlet is opened on the lower wall surface of the intake passage downstream of the reed valve and the oil outlet is communicated with the gear chamber,
A part of the oil flowing into the crank chamber through the intake passage is guided to the gear chamber without flowing in the cylinder direction.
Therefore, it is possible to reduce the amount of oil flowing into the combustion chamber and suppress the generation of white smoke.

Further, in the present invention, the lower end of the crank shaft is sealed by the seal member to seal the crank chamber, and the drive gear and the driven gear are housed in the gear chamber below the seal member. Therefore, the air-fuel mixture in the crank chamber can be prevented from flowing into the gear chamber, and the primary compression ratio of each cylinder is not impaired.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an embodiment of a lubricating device for an internal combustion engine of the present invention, and FIG. 2 is a transverse sectional view of FIG. 1 …… Crankshaft 3 …… Crankcase 31 …… Drive gear 32 …… Oil pump 33 …… Driven gear 42 …… Communication passage

Claims (1)

[Claims] Claim: What is claimed is: 1. A driven gear of an oil pump meshes with a drive gear provided on a crankshaft, the crankshaft is arranged substantially vertically, and a cylinder in a cylinder block is arranged substantially horizontally. An intake passage extending in the direction opposite to the cylinder is connected to the crank chamber formed by the block, and a reed valve that allows only intake to the crank chamber is provided in the intake passage, and the lower end of the crankshaft is sealed by a seal member. To seal the crank chamber, house the drive gear and the driven gear in the gear chamber below the seal member, and operate the oil pump by the rotation of the crank shaft to supply oil to the intake passage. In the device, an oil outlet is opened in the lower wall surface of the intake passage downstream of the reed valve, and the oil outlet is connected to the communication passage. Lubrication system for an internal combustion engine, characterized in that communicates with the gear chamber.