JPS60240815A - Lubricating oil guiding device in two-cycle engine - Google Patents

Abstract

PURPOSE:To introduce a lubricating oil to a connecting part between a crank web and a connecting rod accurately by forming a lip wall part which extends into a gap between the skirt part of a piston and said crank web, continuously with the lower wall surface of an oil feeding port. CONSTITUTION:When a piston 6 rises, a lubricating oil, together with an air fuel mixture, is fed into a crank chamber 2 from a reed valve 9 through an intake port 10. Then, the lubricating oil collides with the wall surface of the intake port 10, partly turning into a wall surface flow, which flows from a lower wall surface 10a and along a lip wall part which is continuously connected to the wall surface 10a, and is introduced to a gap between both opposite crank webs 4. Lubricating oil which flows into the crank chamber 2 in a mist condition is also introduced to the central part of the crank chamber 2, due to the lip wall part 12, without being splashed by the peripheral surface of a web 4, etc., colliding with a connecting rod 7. Accordingly, a connecting part between the web 4 and the connecting rod 7, i.e., the bearing part around a crank pin 5, and the sliding surfaces of the larger end part 7a of the connecting rod 7 and the web 4, can be lubricated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention supplies lubricating oil together with a mixture of fuel and air to the crank chamber in the lower part of the engine body from an air supply boat with an opening that connects connecting rods leading to pistons. The present invention relates to a lubricating oil guide device for a two-stroke engine.

Conventionally, in this type of engine, when the lubricating oil contained in the air-fuel mixture collides with the wall of the air supply boat, a part of it becomes a wall flow and is separated from the air-fuel mixture flow, and also forms a mist on the crank guide. The lubricating oil that flows as it is is scattered on the circumferential surface and outer surface of the crank web, and most of it is scavenged without reaching the connection part with the connecting rod on the inner surface of the web, causing insufficient lubrication to the connection part and causing swelling. However, there is the inconvenience that the amount of lubricating oil must be increased in order to ensure the lubricity of the connecting portion.

In order to eliminate such inconveniences, the present invention provides a lubricating oil guide device that allows lubricating oil to be guided to the connecting portion between the web and the connecting rod without scattering the lubricating oil at locations where lubrication is not required, such as the circumferential surface of the web or the outer surface of the web. Its purpose is to
On the inner wall surface of the crank chamber, a tongue wall portion is formed continuously on the lower wall surface of the opening of the air supply passage, which extends into the gap between the skirt of the side piston and the crank web when the piston is at the bottom dead center. It is characterized by

The present invention will be explained below with reference to the illustrated embodiments.

Referring to FIGS. 1 and 2, (1) shows an engine body composed of an upper cylinder (1&) and a crankcase (1b) consisting of left and right student discount H+-s at the lower part. Crank inside the crankcase (1b)! 7m (21
A pair of left and right crank webs 141 (41) integral with the crankshaft (3) are housed in the housing, and both webs t41 +41
A connecting rod (7) connected to a piston (6) is pivotally attached to a crank pin (5) that extends over the crankcase (1b) at its lower large end (7a), and a cylinder insertion hole (1c) at an upper end of the crankcase (1b) ) is formed with an air supply port uQ that opens into the crank chamber (2) and communicates with the external air supply passage (8) via the reed pulp (9).
) from the oil pump to the fuel-air mixture flowing into the air supply port 00).
The lubricating oil was supplied to the crank N(2) along with the air-fuel mixture from the engine, and the entire side-lead pulp type two-stroke engine was configured with a separate lubrication system. In the drawings, av indicates a scavenging passage.

The above is not particularly different from the conventional one, but according to the present invention,
The skirt portion (6) of the piston (6) when the piston (6) is at the bottom dead center position is shown on the inner wall surface of the crank chamber (2).
A tongue wall part extending into the gap between a) and the crank web (4) is formed continuously on the lower wall surface (10a) of the air supply port (001). In the embodiment shown in FIGS. 1 and 2'', the tongue wall portion 02) integrally extends inward from the inner edge of the lower wall surface (10a) of the air supply port aα, and the air supply boat A tongue wall portion (1 section) approximately symmetrical to the tongue wall portion (121) was also formed at the entrance of the scavenging passage V formed at a position opposite to the tongue wall portion (121).

Next, to explain its operation, as the piston (6) moves upward from the bottom dead center position, lubricating oil is pumped from the reed pulp (9) through the air supply port (101) together with the mixture of fuel and reactor air. The lubricating oil with a large specific gravity collides with the wall of the air supply port (101) and a part of it becomes a wall flow.
The lubricant is guided from 10a) to the opposing gap between both crank webs (4) f41 along the continuous tongue wall a21, and flows into the crank chamber (2) in the form of a mist along with the flow of the air-fuel mixture. Due to the presence of the tongue wall portion (121), oil is not scattered on the circumferential surface of the web 14J, etc., and flows into the crank chamber (
2) and collides with the connecting rod (7), thus connecting the web (4) and the connecting rod (7) by the wall flow and the lubricating oil that collides with the funnel rod (7) and falls. , that is, the bearing part of the crank pin (5) and the sliding surface of the large end (7a) of the core connecting rod (7) and the web (4) are lubricated.

In addition, during the scavenging stroke due to the downward movement of the piston (6) from the top dead center position, a part of the lubricating oil flowing into the scavenging passage Ql) together with the air-fuel mixture collides with the wall surface of the passage Uυ, causing a wall flow. In this case, if the tongue wall part (1 white) is extended to the entrance of the core passage Uυ as in the above embodiment, this backflow lubricating oil will also flow back to the crank chamber (2) side. It is advantageous because it can be used for lubrication.

In this case, all the scavenging passages are located in the opposite direction to the rotational direction
The tongue wall portion 03 is connected to the insertion hole (1Q) by connecting the front and rear ends of the lower wall surface (1oa) of the air supply boat ao+.
(14 is a tongue wall part (14 is a crankcase The tongue wall portion α2 is formed in a relatively long length reaching the split surface of (1b), and the wall surface flow of lubricating oil from the air supply boat 00) flows through the tongue wall portion α2.
The web (4) and the connecting rod (7) are connected along the split surface.

As described above, according to the present invention, the wall flow of lubricating oil is prevented from scattering on the circumferential surface of the crank web along the tongue wall portion continuously formed on the lower wall surface of the air supply boat, and the web and the crank rod are connected to each other. The proportion of lubricating oil that is guided to the connecting part and supplied to the connecting part increases, and even if the supply of lubricating oil is reduced, the

[Brief explanation of the drawing]

Figure 1 shows one of the two-stroke engines equipped with the device of the present invention.
A cut front view of the example, FIG. 2 is a side view taken along line 1-n in FIG. 1, FIG. 3 is a cut side view of another example, and FIG. It is a plan view.

Claims (1)

[Claims] The crank chamber at the bottom of the engine body accommodates the crank web that connects the connecting rod to the piston.
In a two-stroke engine, in which lubricating oil is supplied together with a mixture of fuel and air from an air supply boat opened into the crank chamber, when the piston is at the bottom dead center position, a Lubricating in a two-stroke engine characterized in that a tongue wall extending into the gap between the skirt of the gorge and the web is formed continuously on the lower wall surface of the air supply boat. Oil guide device.