JPS5842569Y2 - Oil blowout prevention device for internal combustion engines - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a device for preventing oil from blowing out to the outside of a valve rocker cover or oil separator that communicates with the crankcase of an internal combustion engine.

Conventionally, in internal combustion engines, blow-by gas is generally extracted from the valve rocker cover that communicates with the crankcase through an oil separator, and then returned to the intake system using negative suction pressure to be combusted. It is being done.

In this process, oil led into the valve rocker cover along with blow-by gas is normally returned to the oil pan at the bottom of the crankcase through an oil return hole provided in the cylinder head. During high-speed rotation or when the amount of oil is abnormally large, the oil cannot be returned completely through the return hole due to scraping up by the crankshaft, an increase in the amount of blow-by gas, an increase in the amount of discharge from the oil pump, etc., and the valve rocker The oil may begin to accumulate inside the cover, fill the oil separator, and finally blow out to the outside.

To prevent this oil from blowing out, you can make the return hole larger, install a crankshaft baffle, or increase the oil reservoir capacity in the oil separator. In some cases, such measures cannot be taken due to constraints, and in some cases, the above measures cannot reliably prevent oil from blowing out.

The present invention was proposed in view of the above circumstances, and is based on an existing balancer shaft installed in the crankcase of a normal internal combustion engine, such as one end of the balancer shaft, which is drilled in the case so as to face the one end. The object of the present invention is to form a centrifugal pump with an extremely simple structure and small size by using the space provided, and to provide a device that reliably prevents oil from blowing out with this centrifugal pump.

In order to achieve this object, the device according to the present invention, in an internal combustion engine having blow-by gas treatment means as described above, opens one end of an oil return pipe in at least one of the rocker cover where oil accumulates or the oil separator. , the other end of this return pipe is communicated with a space surrounding the periphery provided in the case so as to face one end of an existing rotating shaft such as a balancer shaft disposed in the crankcase, and The portion includes an impeller formed by providing blades on a disk fixed by press-fitting the base to one end of the rotating shaft, or an impeller integrally molded on the one end, and an impeller that is close to the front surface of the impeller. A centrifugal pump consisting of a pump cover fixed to the space by press-fitting or the like and a vortex chamber bored in the inner wall of the space opposite to the outer periphery of the blade is disposed, and the vortex chamber includes: It is characterized in that the discharge port is opened at a position facing the oil pan.

As a related prior art, a technique in which an oil separator is formed by utilizing the structure near the end of the balancer shaft can be found in Japanese Patent Application Laid-Open No. 55837/1983.

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings.

In Fig. 1, reference numeral 1 denotes a crankcase. Inside the crankcase 1, an oil pan 2 is provided at the bottom, as in a normal internal combustion engine, and inside there is a crankshaft 3 and a balancer shaft. 4 are arranged.

Further, a valve rocker cover 5 that communicates with the inside of the case 1 is connected to the upper part of the crankcase 1, and the engine body is installed inside the crankcase 1 and the valve rocker cover 5.

The cylinder block 6, cylinder head 7, piston 8, etc. that make up the cylinder are housed inside.

An oil separator 9 is provided on the upper part of the valve rocker cover 5, and a blow-by gas passage 10 communicating with the separator 9 is opened so as to communicate with an air cleaner 11.

Then, the crankcase 1 and the valve rocker cover 5
The blow-by gas inside surrounded by the air cleaner 11. is separated from the oil component while passing through the oil separator 9 due to suction negative pressure. The fuel is sucked into the cylinder together with the air-fuel mixture through the carburetor 12 and is combusted.

Further, an oil return hole 13 is formed in the cylinder head 7 portion within the valve rocker cover 5 so as to return the oil within the valve rocker cover 5 into the oil pan 2.

The above structure and its operation are similar to a normal internal combustion engine having a blow-by gas treatment means.

In the present invention, one end of each of the oil return pipes 15 and 16 is opened so as to communicate with a location where oil accumulates in the valve rocker cover 5 and the oil reservoir chamber 14 of the oil separator 9, respectively. 15
, 16 are assembled into one common return pipe 17, and the tip of the return pipe 17 is connected to the balancer shaft 4 as shown in FIG.
A periphery provided in the crankcase 1 opposite to one end is communicated with a suction port 21 of a centrifugal pump 20 disposed in a space 19 surrounded by a blind plug 18 or the like.

As is clear from FIG. 2, the centrifugal pump 20 is disposed in the space 19, and a boss 24 is attached to the center of a disk 23 fixed to one end of the balancer shaft 4 by press-fitting the base 22. , an impeller 26 formed by providing blades 25 on its outer periphery, and a suction port 21 formed between an impeller 26 and a boss 24 which are fitted into the space 19 in close proximity to the front surface of the blades 25 and fitted into the space 19 by press-fitting means. It consists of an annular pump cover 27 and a vortex chamber 28 bored in the inner wall of the space 19 so as to face the outer periphery of the blade 25, and the vortex chamber 28 has a discharge port 29 to the oil pan. The holes should be drilled so that they communicate with each other.

In addition, 30.31 in FIG. 2 is a bearing member that rotatably supports the end of the balancer shaft 4 on the crankcase 1.
Further, 32 is a balancer shaft drive gear attached to the balancer shaft so as to mesh with the drive gear 33 attached to the crankshaft 3.

With the above configuration, since the impeller 26 of the centrifugal pump 20 rotates as the balancer shaft 4 rotates, a pumping action is generated, and this pumping action causes damage to the inside of the valve rocker cover 5 and the oil separator 9. The oil accumulated in the oil reservoir chamber 14 is sucked into the space 19 through the common return pipe 17 from the return pipes 15 and 16, and is sucked into the space 19 through the suction port 21.
From there, it passes through the impeller 26 and is forcibly returned into the crankcase 1 from the discharge port 29.

Therefore, according to the present invention, the oil accumulated in the valve rocker cover and the oil separator is forcibly returned to the crankcase through the return pipe by the pump action as described above, so that the oil accumulated in the valve rocker cover and the oil separator is forcibly returned to the crankcase. This eliminates the phenomenon in which a large amount of oil accumulates inside, and it is possible to reliably prevent oil from blowing out as seen in conventional internal combustion engines.

Moreover, in the present invention, the centrifugal pump is installed in a space surrounding an existing rotating shaft, such as a balancer shaft, in a space surrounding the crankcase so as to face one end of the existing rotating shaft, such as a balancer shaft. An impeller formed by providing blades on a disk whose base is fixed by press-fitting or the like, or an impeller integrally molded on the one end of the impeller, a pump cover fixed to the space by press-fitting etc. in close proximity to the front of the impeller, and the blades It is formed by a vortex chamber, etc., bored in the wall of the space facing the outer periphery, and therefore, it is intercepted by appropriately utilizing the existing rotating shaft, the space, etc., so the impeller and its The suction port, vortex chamber, etc. are extremely simple and compact, and no special means of transmitting power to the impeller is required, so the structure is expected to be simple and inexpensive in practical terms. can do.

In carrying out the present invention, the structure of the centrifugal pump is not limited to the illustrated embodiment, and the rotating shaft on which the impeller of the pump is provided is not limited to the balancer shaft, but may be installed elsewhere in the crankcase. You may also use the rotation axis of

Further, in the above embodiment, one end of the oil return pipe was opened to both the valve rocker cover and the oil separator, but even if it is connected to only one of them,
Some effects can be expected, and especially when a return pipe is connected to the oil separator, an effect can be obtained in which the conventional oil return mechanism in the oil separator can be made unnecessary.

[Brief explanation of the drawing]

Fig. 1 is a schematic vertical sectional view showing one embodiment of the present invention;
The figure is an enlarged cross-sectional view of the centrifugal pump portion. 1... Crank case, 2... Oil pan, 3... Crankshaft, 4... Balancer shaft, 5... Valve rocker cover 6...
... Cylinder block, 7 ... Cylinder head, 8 ... Piston, 9 ... Oil separator, 10 ... Blow high gas passage, 11
... Air cleaner, 12 ... Carburetor,
13...Oil return hole, 14...Oil reservoir chamber, 15°16.17...Oil return pipe, 18...Blind plug, 19... ...Space part, 2
0...Centrifugal pump, 21...Suction port,
22... Base, 23... Disc, 24...
...Boss, 25...Feather, 26...
... Impeller, 27 ... Pump cover, 28 ...
... Vortex chamber, 29 ... Discharge port, 30 ...
...Bearing member, 31...Bearing member, 32...
... Balancer shaft drive gear, 33... Drive gear.

Claims (1)

[Scope of utility model registration request] In an internal combustion engine of a type in which blow-by gas is guided from inside the valve rocker cover communicating with the crankcase to the outside of the cover via an oil separator for treatment,
One end of the oil return pipe is connected to at least one of the inside of the valve rocker cover and the inside of the oil separator, and the other end of the oil return pipe is connected to one end of an existing rotating shaft such as a balancer shaft installed in the crankcase. The blade is connected to a surrounding space provided in the case so as to face the rotating shaft, and a blade is provided in the space on a circular plate fixed by press-fitting a base to one end of the rotating shaft. an impeller integrally formed on the one end; a pump cover fixed to the space by press-fitting or the like in close proximity to the front surface of the impeller; and a wall of the space facing the outer periphery of the impeller. An oil blowout for an internal combustion engine, characterized in that a centrifugal pump is disposed in a vortex chamber bored in the vortex chamber, and a discharge port is bored in the vortex chamber at a position facing an oil pan. Prevention device.