JPH0240848B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lubrication device for a two-stroke internal combustion engine suitable for use in outboard motors and the like.

[Prior Art] Two-stroke internal combustion engines are often used in outboard motors and the like. In a two-stroke internal combustion engine, the load acting on the big end bearing portion is very large, and it is necessary to reliably lubricate this portion. Therefore, in conventional two-stroke internal combustion engines, it is possible to supply lubricating oil to the big end bearing section, which is pumped under pressure by a lubricating pump, in addition to the lubricating oil supply path that is supplied to the crank chamber as a mixture with fuel. A method is proposed.

[Problems to be Solved by the Invention] However, in the conventionally proposed method, lubricating oil is first supplied to the main bearing of the crankshaft;
The large end bearing is designed to be lubricated by the lubricating oil that flows down after the main bearing is lubricated, and the required amount of lubricating oil is not necessarily supplied to the large end bearing.

SUMMARY OF THE INVENTION An object of the present invention is to provide a lubricating device that can reliably lubricate a large end bearing of a two-stroke internal combustion engine.

[Means for Solving the Problems] The present invention has a plurality of cylinders, and the crank chamber of each cylinder is secured by a seal ring installed in a ring installation groove provided on the inner surface of the engine body and the entire circumference of the crankshaft. A lubricating device for a two-stroke internal combustion engine, which includes: a lubricating oil feed path provided in the engine body; a ring-shaped oil groove provided around the entire circumference of the seal ring and facing the opening of the oil feed path; Provided in the seal ring,
It has an oil hole that connects the oil groove to the ring mounting groove, and an oil supply path that is provided on the crankshaft and supplies lubricating oil introduced into the ring mounting groove to the big end bearing.

[Operation] During engine operation, the seal ring rotates relative to the engine body and the crankshaft. In order to reliably supply the lubricating oil supplied from the oil supply path provided on the engine body side to the big end bearing via the seal ring and the crankshaft, the seal ring must be placed in one of the above relative positions. Even in this case, an oil supply path from the engine body side to the crankshaft side must be secured.

At this time, in the present invention, between the engine body and the seal ring, a ring-shaped oil groove provided around the entire circumference of the seal ring allows oil to be supplied even when the seal ring is in a relative position to the engine body. Secure the route. Also, between the seal ring and the crankshaft,
The ring mounting groove provided around the entire circumference of the crankshaft ensures an oil delivery path no matter where the seal ring is positioned relative to the crankshaft.

As a result, the lubricating oil supplied from the oil supply path on the engine body side is always reliably supplied to the big end through the ring-shaped oil groove and oil hole of the seal ring, the ring mounting groove of the crankshaft, and the oil supply path. Supplied to the bearing section.

[Embodiment] Fig. 1 is an explanatory diagram showing an embodiment in which the present invention is applied to a 2-stroke V-type internal combustion engine for an outboard motor, and Fig. 2 is an enlarged view of the main part of Fig. 1. It is a partially broken sectional view shown.

Cylinder (body) 11 and crankcase 12
The vertical crankshaft 13 is connected to the upper main bearing 1 between
4. It is supported via the intermediate main bearing 15 and the lower main bearing 16. The upper part of the upper main bearing 14 is sealed by an oil seal 17, and the lower part of the lower main bearing 16 is sealed by an oil seal 18. Further, a drive shaft 19 is connected to the lower end of the crankshaft 13, which is vertically installed in a casing (not shown) and is capable of driving a propulsion propeller.

Here, the cylinder (body) 11 and the crankcase 12 constitute an engine main body in the present invention.

As mentioned above, the internal combustion engine has four cylinders, the first cylinder, the second cylinder, and the third cylinder and the fourth cylinder each form a V-shape, and each cylinder has a phase difference of 90 degrees. It is considered operational. The crankshaft 13 has upper and lower crank webs 20, 21.
is provided. Moreover, between the crank web 20 and the intermediate main bearing 15 of the crankshaft 13,
The first crank pin 22 and the second crank pin are adjacent to each other.
A crank pin 23 is provided. Additionally, a third crank pin 24 and a fourth crank pin 25 are provided between the intermediate main bearing 15 and the crank web 21 of the crankshaft 13, which are adjacent to each other. The above crank pins 22, 23, 24, 25
A connecting rod 27, to which a piston (not shown) of each cylinder is connected, is connected to the large end portion of the connecting rod 27 via a large end bearing portion 26, respectively.

Furthermore, seal rings 28 are attached to the upper and lower portions of the crank pins 22, 23, 24, and 25 of the crankshaft 13, and are in sliding contact with the inner surfaces of the cylinder (body) 11 and the crankcase 12.
First to fourth crank chambers 29, 30, 3
1 and 32, thereby making it possible to prevent the air-fuel mixture from moving between the crank chambers. That is, in this internal combustion engine, each cylinder operates with a phase difference of 90 degrees as described above, so each crank chamber 29, 3
Although the phase difference occurs in the internal pressure pulsations at 0, 31, and 32, the existence of the seal ring 28 prevents the air-fuel mixture from flowing into different crank chambers.
In the figure, 33 is a carburetor for the first and second cylinders, 34 is a carburetor for the third and fourth cylinders, and 35 is an intake duct. Each vaporizer 33,3
At 4, lubricating oil is supplied into the air and fuel mixture, and the lubricating oil is supplied to the air and fuel mixture, which flows into the intake manifolds 36, 3.
It is led to each crank chamber 29, 30, 31, 32 via a reed valve built in 7.

Therefore, in this embodiment, the crankcase 12 is provided with an upper oil passage 38 that opens at one end at the bottom of the intake manifold 36, and
A lower oil feed passage 39 is bored, one end of which opens at the bottom of the intake manifold 37. The upper oil passage 38 is
In the crankcase 12, the first upper oil passage 3
8A and a second upper oil supply passage 38B, the first upper oil supply passage 38 is opened toward the outer periphery of the seal ring 28 that defines the upper part of the first crank chamber 29,
The second upper oil feed passage 38B is opened toward the outer periphery of the seal ring 28 that defines the upper part of the second crank chamber 30. The lower oil passage 39 is branched into a first lower oil passage 39A and a second lower oil passage 39B within the crankcase 12, and the first lower oil passage 39A defines an upper part of the third crank chamber 31. The second lower oil feed passage 39B is opened toward the outer periphery of the seal ring 28 that defines the upper part of the fourth crank chamber 32. In addition, each oil supply path 38A, 38B, 39A,
39B is provided with a check valve 40 that allows lubricating oil to flow from the intake manifolds 36, 37 to the respective crank chambers 29, 30, 31, 32 and prevents the lubricating oil from flowing in the opposite direction.

Further, the seal ring 28 is attached to a ring mounting groove 4 formed in the crankshaft 13, as shown in FIG.
It is housed in 1. Each crank chamber 29, 30,
Seal ring 28 defining the upper part of 31, 32
On the outer periphery of each oil passage 38A, 38B, 39
A ring-shaped oil groove 42 is formed that faces each opening A and 39B. Furthermore, each of the above seal rings 28
Oil holes 43 that communicate the oil groove 42 with the inner circumferential surface of the seal ring 28 are bored at a plurality of positions in the circumferential direction of the oil groove 42 . That is, the oil groove 42 and the oil hole 43 form a communication path in the present invention, and allow lubricating oil from each oil feed path 38A, 38B, 39A, and 39B to be introduced into the bottom 41A of the ring mounting groove 41.

Furthermore, in the portion of the crankshaft 13 that forms the ring mounting groove 41 into which the lubricating oil is introduced, a ring mounting groove 41 is provided in the portion closest to the outer periphery of each crank pin 22, 23, 24, 25.
An oil supply passage 44 as shown in FIGS. 3 and 4 is cut in order to allow the lubricating oil introduced therein to flow down to each large end bearing portion 26.

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

During operation of the internal combustion engine, each carburetor 3
3 and 34, lubricating oil is supplied into the air-fuel mixture to each crank chamber 2 on the intake stroke.
Inhaled on 9, 30, 31, 32. Here, a portion of the lubricating oil adheres to the wall surfaces of each of the intake manifolds 36 and 37, becomes a wall flow, and accumulates in the lower portions thereof. On the other hand, the crank chambers 29, 30, 31,
The suction negative pressure of 32 opens the check valve 40, and the lubricating oil accumulated in the lower part of each intake manifold 36, 37 is transferred to the oil supply passages 38, 38A, the oil groove 42, the oil hole 43, and the ring. The oil is supplied to the large end bearing portion 26 of the first crank pin 22 in the first crank chamber 29 through the mounting groove 41 and the oil supply path 44, and
8B, oil groove 42, oil hole 43, ring mounting groove 41,
The oil is supplied to the large end bearing portion 26 of the second crank pin 23 in the second crank chamber 30 through the oil supply path 44, and is supplied to the oil feed paths 39, 39A, the oil groove 42, the oil hole 43,
The oil is supplied to the big end bearing portion 26 of the third crank pin 24 in the third crank chamber 31 through the ring mounting groove 41 and the oil supply path 44, and the oil is supplied to the large end bearing portion 26 of the third crank pin 24 in the third crank chamber 31 through the oil supply path 39, 39B, the oil groove 42, the oil hole 43, and the ring installation. Groove 41, oil supply path 4
4 to the large end bearing portion 26 of the fourth crank pin 25 in the fourth crank chamber 32.

However, in the case of an internal combustion engine, the seal ring 28 rotates relative to each of the crankcase 12 and the crankshaft 13 during operation of the engine.
Then, the oil feed passage 3 provided on the crankcase 12 side
The lubricating oil supplied from 8 and 39 is passed through the seal ring 28 and the crankshaft 13 to the big end bearing part 26.
In order to reliably supply oil to the oil, a path for feeding oil from the crankcase 12 to the crankshaft 13 must be ensured no matter which of the above-mentioned relative positions the seal ring 28 is in.

At this time, in the above embodiment, between the crankcase 12 and the seal ring 28, the ring-shaped oil groove 42 provided around the entire circumference of the seal ring 28 allows the seal ring 28 to be connected to the crankcase 12 and either side. Even if they are in relative positions, the oil supply route is secured.
Further, between the seal ring 28 and the crankshaft 13, a ring mounting groove 41 provided around the entire circumference of the crankshaft 13 allows the seal ring 28 to be attached to the crankshaft 13.
An oil supply path is secured in any of the relative positions of 3.

As a result, the oil feed path 3 on the crankcase 12 side
The lubricating oil supplied from 8 and 39 is always reliably supplied through the ring-shaped oil groove 42 and oil hole 43 of the seal ring 28, the ring mounting groove 41 of the crankshaft 13, and the oil supply passages 44 and 45. End bearing part 26
supplied to

Note that the lubricating oil introduced into the ring mounting groove 41 is not supplied from the oil supply passage 44 to the large end bearing portion 26, but is instead supplied to the large end bearing portion 26 through an oil supply passage 45 drilled in the crankshaft 13 as shown in the second diagram. It may also be supplied to the end bearing portion 26.

Further, in the above embodiment, a case has been described in which the lubricating oil accumulated in the lower part of each intake manifold 36, 37 is sucked by the suction negative pressure of each crank chamber 29, 30, 31, 32. However, in the present invention, the lubricating oil accumulated in the lower part of the intake manifold may be force-fed to the oil supply path side by the lubricating oil pump. The lubricating oil may be fed under pressure to the oil supply path from a system separate from the intake manifold.

[Effects of the Invention] As described above, according to the present invention, the lubricating oil supplied through the oil passage is supplied to the ring-shaped oil groove and oil hole provided in the seal ring, the ring mounting groove provided in the crankshaft, The oil is reliably supplied to the big end bearing through the oil supply path.

[Brief explanation of drawings]

FIG. 1 is a plan view showing a main part of an internal combustion engine to which an embodiment of the present invention is applied; FIG. 2 is a partially cutaway view showing an enlarged main part of FIG. 1; The figure is a sectional view showing an enlarged main part of FIG. 2, and FIG. 4 is a sectional view taken along the - line in FIG. 2. 12...Crank case, 13...Crankshaft, 26...Big end bearing, 28...Seal ring, 29, 30, 31, 32...Crank chamber, 3
8, 38A, 38B, 39, 39A, 39B...
Oil feed path, 41...Ring mounting groove, 42...Oil groove,
43... Oil hole, 44, 45... Oil supply path.

Claims (1)

[Claims] 1. In a lubrication system for a two-stroke internal combustion engine that has a plurality of cylinders and defines the crank chamber of each cylinder by the inner surface of the engine body and a seal ring installed in a ring installation groove provided around the entire circumference of the crankshaft. , a lubricating oil feed path provided in the engine body, a ring-shaped oil groove provided around the entire circumference of the seal ring and facing the opening of the oil feed path, and a ring-shaped oil groove provided in the seal ring, and the oil groove is attached to the ring. A lubricating device for a two-stroke internal combustion engine, comprising an oil hole communicating with the groove and an oil supply path provided in the crankshaft for supplying lubricating oil introduced into the ring mounting groove to the big end bearing.