JPS606585Y2 - Overhead valve engine lubrication system - Google Patents

Description

[Detailed description of the invention] This invention relates to a lubrication system for an overhead valve engine, and the main purpose of this invention is to ensure that the valve train housed in the rocker arm chamber can be reliably lubricated by a lubrication system with a simpler structure. do.

Typically, overhead valve engines use a pressure-feed lubrication system.

However, this method requires a large number of components in the lubrication system, and
Since a large number of various oil passages must be formed on the engine plate wall or the rotating shaft, it is inevitable that the manufacturing cost of the lubricating device as a whole increases and the engine structure becomes complicated.

Therefore, the present applicant has previously developed an overhead valve type engine.
In addition to adopting a splash-type lubrication system, we proposed a lubrication system that simplified the lubrication system by providing a blazer chamber on the peripheral wall of the rocker arm chamber to guide mist-like oil from the crank chamber to the rocker arm chamber.

However, it has been found that this device has a problem in that blow-by gas blows up from the return oil path that is designed to return lubricating oil into the rocker arm chamber, making it difficult for the lubricating oil to return from the rocker arm chamber.

This idea was proposed in consideration of these points, and it follows the technology of the previous patent application, which uses a splash type refueling system in an overhead valve type engine and provides a blazer chamber on the peripheral wall of the rocker arm chamber. A return oil/gas passageway is formed from the wall surface facing the blazer chamber forming wall to the crank chamber, so that surplus lubricating oil can be smoothly returned from the rocker arm chamber to the crank chamber.

Hereinafter, embodiments of the present invention will be described based on the drawings.

FIG. 1 is a longitudinal sectional front view of the main parts of an overhead valve type single-cylinder air-cooled electroplated engine.

In the figure, an engine 1 is composed of a crankcase 2, a cylinder 3, and a head block 4 as main outer shell structures,
Inside it is a piston 5, a connecting rod 5a1 and a crankshaft 6.
, a camshaft 7, intake and exhaust valves 8a, 8b, a valve train 9, and other moving members.

The valve train 9 includes a pair of rocker arms 10a and 10b provided corresponding to intake and exhaust valves 8a and 8b, a tappet 11 driven by a camshaft 7, and a rocker arm lea and 10b that controls the operation of the tappet 11. It consists of a bushing rod 12 that conveys the information.

As shown in FIG. 2, the above rocker arms 10a and 10b are swingably supported by a pair of brackets 13 fixed to the head block 4 via a rocker arm shaft 14.

A rocker cover 15 is fixed to the bracket 13 so as to cover the outer surface of the rocker arms 10a-10b.

The rocker arm chamber 16 defined by the rocker cover 15 and the upper surface of the head block 4 includes a hollow hole 17 provided near the lower end of the tappet 11 and a tubular bushing rod cover 18 that covers the circumference of the bushing rod 12. It is communicated with the crank chamber R through.

A blazer 19 is attached to the outer surface of the side wall of the rocker cover 15 near the bushing rod 12.

This blazer 19 consists of a box-shaped pleather case 20 and a reed valve unit 21 which is held between this and a rocker cover 15 via a gasket.

The reed valve unit 21 includes a base plate 22, a closed valve 23 fixed to the base plate 22, and a valve opening amount regulating plate 24.

The inside of this pleather case 20 is communicated with the locker chamber 16 through a breather hole 25 provided through the locker cover 18 and the base plate 22, and is also communicated with an air cleaner 28 via a breather pipe 27 fitted externally into an outlet pipe 26 on the side wall thereof. be done.

An oil return/gas vent 29 is formed on the side wall of the rocker cover 15 opposite to the side wall where the blazer 19 is disposed. The lubricating oil stagnant in the rocker arm chamber 16 is returned to the crank chamber R by being connected to the gas venting pipe 31 to extract blow-by gas from the crank chamber R to the rocker arm chamber 16. .

In the figure, reference numeral 32 is an oil spoon colinearly fixed to the large end of the funnel rod 5a, and 33 and 34 are bush rod covers 12.
35 is an oil guide port provided on the upper surface of the back of the rocker arms 10a and 10b, 36 is a return oil port provided at the bottom of the blazer hole 25, and 37 is a sealing device fitted on the upper and lower ends of the crankcase 2. an oil shield plate that covers the formed gas outlet hole 30 from the inside;
Reference numeral 38 denotes an oil mist blow-up hole that communicates the bottom part of the rocker arm chamber 16 with the crank chamber R.

Note that this oil mist blow-up hole 38 has an inner diameter smaller than that of the return oil gas vent pipe 31, and in this embodiment, the inner diameter of the oil mist blow-up hole 38 is approximately 3.5 to 4 mm, and the return oil gas vent pipe 31 has a smaller inner diameter. The inner diameter of the extraction tube 31 is approximately 8 mm.

Further, the tappet hole formed in the crankcase 2 is formed at a position where the lubricating oil scooped up by the oil spoon 32 is bounced off the inner surface of the crankcase and then bounced up by the crankshaft 6 to reach the lubricating oil.

According to the above configuration, not only the engine moving members facing the crank chamber R but also the valve train 9 can be reliably lubricated despite the droplet lubrication type oil supply system.

That is, as the oil spoon 32 scrapes up and scatters as the crankshaft 6 rotates, each moving member such as the piston 5, connecting rod 5a1, crankshaft 6, camshaft 7, tappet 11, etc. is forcibly lubricated, and the inner surface of the crankcase 2 and The lubricating oil that has been bounced off by the crankshaft 6 flows into the inner space of the bushing rod cover 18 from the oil port 17 formed at the bottom of the tappet 11, and is sent into the rocker arm chamber 16 by the vertical movement of the tappet 11 and bushing rod 12. It will be done.

In addition, since the blazer 19 is outside the rocker cover 15, the mist-like oil and blow-by gas that filled the crank chamber R are removed from the inside of the bushing rod cover 18, the oil mist blow-up hole 38, and the gas vent/return oil pipe 31. The oil mist reaches the rocker arm chamber 16 through the contact points between the rocker arms 10a and 10b and the bushing rod 12 or the intake and exhaust valves 8a and 8b, and the rocker arms 10a and 10b.
10b10 Tsuka - Attach to the arm shaft 14, etc., and lubricate these.

On the other hand, the blow-by gas is led out to the air cleaner 28 through the blazer pipe 27 via the blazer 19.

After the engine 1 is stopped, the oil stored in the oil inlet 35 prepares for the next engine start.

Then, the gas accumulated in the rocker arm chamber 16 is returned to the crank chamber R through the return gas vent pipe 31.

As explained above, according to the present invention, the crank chamber and the rocker arm chamber are communicated with each other through the outer skin structure that houses the valve train, and a blazer is provided on the peripheral wall of the rocker arm chamber, and the blazer is provided inside the crank chamber. Splashed lubricating oil can be channeled into the rocker arm chamber.

Thereby, the moving member within the rocker arm chamber can be reliably lubricated with a simple structure.

In addition, the blow-by gas in the crankcase is led out from the gas outlet to the rocker arm chamber, and while flowing across the rocker arm chamber, most of the oil contained in the blow-by gas is separated and removed. Since the oil is separated, the blower performance is improved and the outflow of oil due to blow-by gas can be minimized.

In addition, the rocker arm chamber and the crank chamber are communicated with each other by a return oil gas vent pipe with a relatively large inner diameter, so that lubricating oil returns from the rocker arm chamber to the crank chamber in this pipe, and from the crank chamber to the rocker arm. Since the blow-by gas flowing into the chamber is smoothly replaced, lubricating oil can be smoothly returned from the rocker arm chamber to the crank chamber.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal sectional front view of the main parts of an overhead valve type engine, and FIG. 2 is a sectional view taken along the line 1--2 in FIG. 1. 1...Engine, 5a...Connecting rod, 6...Crankshaft, 16...Tatsuka arm chamber, 17...Oil feed channel entrance, 18...
...Bush rod cover, 19...Breazer device, 25...19 inlet, 29...Oil return and gas vent port, 30...Oil Return/gas outlet hole, 31...Oil return/gas vent path, 32...
...Oil spoon, 37...Oil shield plate, R.
...Crank chamber.

Claims (1)

[Scope of utility model registration request] The large end of the connecting rod 5a, which is connected to the crankshaft 6 by using an oil passage inside the bushing rod cover 18 of the overhead valve engine 1 and communicating between the crank chamber R and the rocker arm chamber 16 through this oil passage, is An oil spoon 32 is fixed to the bottom of the crank chamber R, and when the lubricating oil stored at the bottom of the crank chamber R is scooped up by the oil spoon 32 and splashed back against the inner wall of the crank chamber R, it is splashed by the crankshaft 6. The rotational direction of the crankshaft 6 and the formation position of the oil feed path 17 are set so that the oil feed path is raised and jumps into the oil feed path entrance 17, and a blazer is placed outside the oil feed path outlet that opens into the rocker arm chamber. At the same time as opening the inlet 25 of the device 19, an oil return/gas outlet 29 is opened at the opposite position, and an oil return/gas outlet 30 is located in the upper part of the crank chamber R on the same side as the gas vent 29. The overhead valve engine is characterized in that the gas vent port 29 and the gas outlet hole 30 are connected through an oil return/gas vent passage 31, and an oil shield plate 37 is provided inside the gas outlet hole 30 of the crank chamber R. lubricating device.