JPH0311367Y2 - - Google Patents

Description

[Detailed explanation of the invention] [Purpose of the invention] (Field of industrial application) This invention collects the oil content of the mixed fuel that adheres to the wall of the scavenging passage and supplies it to the crankshaft bearing. The present invention relates to a lubrication system for a two-stroke engine.

(Prior Art) In a two-stroke engine, regardless of the refueling method, a portion of lubricating oil is mixed with fuel and sent to a combustion chamber to be burned. On the other hand, the scavenging passage is often located above the crankshaft bearing, and in this case, an oil groove is provided in the scavenging passage wall, and an oil supply hole drilled in the bottom of the groove is guided to the crankshaft bearing. The oil that adheres to the walls and falls is collected and used to lubricate the bearings.

However, the oil groove used to collect this oil disturbs the shape of the scavenging passage, which often creates flow resistance and reduces scavenging efficiency, that is, engine output.Also, when the cylinder is tilted forward, the oil The flow passes through an area without an oil groove,
These oil grooves often do not necessarily have a shape that makes it easy to collect oil. For this reason, if the width of the oil groove is increased, the capacity of the recess is increased, resulting in an increase in turbulence in the scavenging air flow.

(Problem to be solved by the invention) This invention was made in view of the problems mentioned above. It improves the shape of the oil groove, makes it easier to collect oil even in forward-inclined cylinders, and improves the shape of the oil groove. Due to its presence, turbulence in the scavenging airflow is reduced so that engine performance is not affected2.
The purpose is to provide a lubricating device for cycle engines.

[Structure of the idea]

(Means for solving the problem) In line with the above purpose, this invention is constructed as follows. That is, a scavenging passage is formed that opens from above both side walls of the crankcase that pivotally supports the crankshaft, protrudes above the crankshaft bearing, and rises upward while curving, and is arranged on the curved wall surface of the scavenging passage. In a 2-cycle engine in which the bottom surface of the oil groove is communicated with the crankshaft bearing portion through an oil supply hole, and the cylinder with such a scavenging passage is tilted forward with respect to the crankshaft, the oil groove is connected to the cylinder. When viewed from above parallel to the axis, it is set in a shape that is elongated in the lateral direction and whose inner side is inclined rearward on the side opposite to the forward inclination of the cylinder, and
The bottom surface is formed into a plane perpendicular to the cylinder axis, and an oil supply hole communicating with the crankshaft bearing is opened at the outermost part of the bottom surface.

(Function) In this way, the oil that adheres to the passage wall surface and falls is collected in the oil groove and sent to the crankshaft bearing section, where it is used for lubrication.

The oil groove is parallel to the cylinder axis when viewed from above, and is elongated in the lateral direction, with the inner side slanting backwards on the opposite side to the forward tilt of the cylinder, so that it can be used for oil flow. It has the same effect as increasing the width, and even when the cylinder tilts forward, the amount of oil collected increases, supplying sufficient lubricating oil to the crankshaft bearing.

Even if the width increases in this way, the oil groove itself is long and narrow, so the capacity of the recess is small, and the existence of the oil groove does not disturb the scavenging air flow and increase the flow resistance, improving the scavenging efficiency. Holds the engine's high power well.

In addition, since the oil supply hole opens at the lowest position of the bottom of the oil groove for the forward-inclined cylinder, the collected oil is efficiently sent to the crankshaft bearing, increasing the amount of collected oil and providing abundant lubrication. It will be guaranteed.

(Example) The following describes an example of this invention with reference to figures.

FIG. 1 shows the main parts of a two-stroke engine taken longitudinally along the axis of the crankshaft, where a cylinder designated by reference numeral 1 is tilted forward, and a crankcase 2 is connected to the lower end of the cylinder. A crank wheel 3 is pivotally supported within the crankcase 2 so that the gap is as small as possible, and a connecting rod 6 is connected between a crank pin 4 and a piston 5. 7 is a bearing portion of the crankshaft 8, and 9 is an oil seal that seals the inside of the crankcase 2.

The lower ends of the scavenging passages 10 are open on both sides of the upper part of the crankcase 2, and the scavenging passages 10 protrude from both sides, that is, above the crankshaft bearing 7, rise upward while curving, and pass through the outside of the cylinder 1. This opens into the cylinder 1 as a scavenging port 11. The intake port and the exhaust port open on the front and rear sides of the cylinder 1.

An oil groove 13 is recessed in the curved wall surface 12 at the lower part of the scavenging passage 10 .

As shown in FIGS. 2 and 3, this oil groove 13 is elongated in the lateral direction when viewed from above, parallel to the axis of the cylinder, and its inner side is inclined rearward on the opposite side to the direction in which the cylinder is tilted forward. It is set in a shape that looks like this.

Further, the bottom surface 13a of the oil groove 13 is finished into a flat surface perpendicular to the axis of the cylinder 1, and an oil supply hole 14 is opened at the outer end thereof. Oil supply hole 1
The lower end of 4 communicates with the upper part of oil reservoir 15 between crankshaft bearing 7 and oil seal 9.

Furthermore, the scavenging passage 10 is formed from the upper end of the curved wall surface 12 to the connected cylinder 1;
On the cylinder 1 side, the main passage 10a and the sub passage 1
0b, and the oil groove 13 is located on an extension of the separation wall 16.

The scavenging air flow that passes through the scavenging passage 10 from the crank chamber 2 and is supplied to the cylinder 1 combustion chamber is a mixture of fuel and lubricating oil, and the oil adheres to the wall surface of the scavenging passage 10, causing an accumulation of adhesion. It twists and flows down the wall. On the way down, the oil is collected in the oil groove 13, falls through the oil supply hole 14 into the oil reservoir 15, and is supplied to the crankshaft bearing 9 for lubrication.

The oil groove 13 is parallel to the axis of the cylinder, viewed from above, and has a shape that is elongated in the lateral direction and whose inner side is inclined rearward on the side opposite to the forward inclination of the cylinder, so that the oil can flow. This has the same effect as when the width is expanded, and even when the cylinder 1 is tilted forward, the amount of oil collected increases, and sufficient lubricating oil is supplied to the crankshaft bearing portion 9.

Even if the width increases in this way, since the oil groove 13 itself is long and narrow, the capacity of the recess is small, and in addition to being located on an extension of the separation wall 16, the presence of the oil groove 13 makes it easier to clean. The airflow is not disturbed and the flow resistance is not increased, the scavenging efficiency is high, and the high output of the engine is maintained.

Also, for the forward-inclined cylinder, the bottom surface of the oil groove 1
Since the oil supply hole 14 is opened at the lowest position of the oil supply hole 3a, the collected oil is efficiently sent to the crankshaft bearing 7, thereby increasing the amount of collected oil and ensuring a sufficient amount of lubricating oil.

[Effect of idea]

As described above, the two-stroke engine lubricating device according to the present invention has a scavenging passage that opens from above the both side walls of the crankcase that pivotally supports the crankshaft, protrudes above the crankshaft bearing, and rises upward while curving. The bottom surface of the oil groove formed on the curved wall surface of the scavenging passage is communicated with the crankshaft bearing part through the oil supply hole, and the cylinder having such a scavenging passage is tilted forward about the crankshaft. In the two-stroke engine, the oil groove is set in such a shape that it is parallel to the cylinder axis and is elongated in the lateral direction when viewed from above, and that the inner side is inclined rearward on the side opposite to the forward inclination of the cylinder. Along with
The bottom surface is formed into a plane perpendicular to the cylinder axis, and an oil supply hole that communicates with the crankshaft bearing is opened at the outermost part of the bottom surface, increasing the amount of oil collected and improving the crankshaft. Sufficient lubricating oil can be supplied to the bearing part, making it particularly suitable when the cylinder is tilted forward.The existence of oil grooves does not disturb the scavenging air flow and increase flow resistance, resulting in high scavenging efficiency. Therefore, a high engine output can be maintained, and the performance of the lubrication system for a two-stroke engine with a simple structure can be greatly improved.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional front view of the main part of a two-stroke engine showing an embodiment of this invention, and Fig. 2 is a cross-sectional view taken from Fig. 1 A-A.
FIG. 3 is an enlarged side view of the divided crankcase as seen from the arrows, and FIG. 3 is a plan view taken along the line B--B in FIG. 1...Cylinder, 2...Crankcase, 7...
...Crankshaft bearing portion, 8...Crankshaft, 10...Scavenging passage, 12...Curved wall surface, 1
3...Oil groove, 14...Oil supply hole.

Claims (1)

[Scope of utility model registration request] A scavenging passage is formed that opens from above both side walls of the crankcase that pivotally supports the crankshaft, protrudes above the crankshaft bearing, and rises upward while curving.Oil grooves are arranged on the curved walls of the scavenging passage. The bottom surface of the cylinder is connected to the crankshaft bearing through an oil supply hole,
In a two-stroke engine in which the cylinder with such a scavenging passage is tilted forward around the crankshaft, the oil groove is horizontally long and narrow when viewed from above, parallel to the cylinder axis, and has an inner side. The cylinder is set in a shape that slopes backwards on the opposite side from the forward slope, and the bottom surface is formed into a plane perpendicular to the cylinder axis, and the outermost part of the bottom surface communicates with the crankshaft bearing. A lubricating device for a two-stroke engine, characterized in that an oil supply hole is opened.