JPH04179813A - Breather for v-type internal combustion engine - Google Patents

Abstract

PURPOSE:To remove mist with remarkably simple structure so as to exhibit a breather function by providing an opening portion and a passage in a camshaft, interposing a one-way valve between one end of the passage and a breather chamber, and communicating the breather chamber with an air cleaner. CONSTITUTION:Gas staying inside a crank chamber 3 is introduced from an opening portion 12 of a camshaft 5 into a passage 11, and the gas staying in the passage 11 flows into a breather chamber 10 upon opening of a one-way valve 14 when a pressure of the passage 11 becomes larger than a predetermined value of a pressure of the breather chamber 10. The camshaft 5 is rotated so that centrifugal force acts on mist mixed in the gas so as to restrain excess mist from flowing in the opening portion 12. The gas from which the excess mist has been removed is introduced from the passage 11 into the breather chamber 10 through the one-way valve 14. Therefore, separation of the mist can be achieved with simple structure.

Description

Detailed Description of the Invention A1 Object of the Invention (1) Industrial Application Field The present invention is characterized in that cylinders are connected in a V-shape on the left and right in the upper part of a crankcase forming a crank chamber, and cylinders are connected to the crankshaft and The present invention also relates to a breather device for a V-shaped internal combustion engine in which a camshaft located at an upper position is rotatably supported by a crankcase in parallel with each other.

(2) Prior art Conventionally, such a device has been used, for example, in the
It is known from the publication No.

(3) Problems to be Solved by the Invention In the above-mentioned conventional device, the gear chamber, which is provided on the camshaft and the crankshaft and accommodates mutually meshing gears and communicates with the crank chamber, is provided with a cover on the side of the crankcase. A breather hole is formed in the upper wall surface of the gear chamber, and a breather chamber is formed between the breather case, which is fixed to the outer surface of the crankcase and covers the outer end of the breather hole, and the outer surface of the crankcase. A deflector is provided on the inner surface of the cover so as to cover the inner end of the breather hole. Breather gas in the gear chamber enters a chamber between the deflector and the cover from a gas inlet provided in the deflector, separates mist-like oil in the chamber, and then is led out from the breather hole to the breather chamber.

According to such a conventional configuration, a deflector for forming a chamber for separating mist must be fixed to the cover or provided integrally with the cover, resulting in a complicated structure.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a breather device for a V-type internal combustion engine that has a simple structure and is capable of separating mist.

B0 Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, according to the present invention, the outer surface of the crankcase has a groove between the crankcase and the camshaft at a position corresponding to one end of the camshaft. A cover forming a breather chamber is fixed to the camshaft, and the camshaft is provided with an opening along the radial direction of the camshaft to communicate with the crank chamber, and a passage communicating with the opening and extending toward one end in the axial direction. A one-way valve that opens when the pressure in the passage exceeds a predetermined value is interposed between one end of the passage and the breather chamber, and the breather chamber is communicated with an air cleaner.

(2) Effects According to the above configuration, the gas in the crank chamber is guided from the opening of the camshaft into the passage and through the one-way valve to the breather chamber, and further from the breather chamber to the air cleaner. When the gas is guided from the opening to the passage, the camshaft is rotating and the opening runs along the radial direction of the camshaft, so the mist entrained by the gas is subject to centrifugal force. acts, and therefore the gas from which excess mist has been removed is introduced into the passage. Moreover, since the camshaft is located above the crankshaft, a sufficient height above the oil level in the crank chamber can be secured to lead out the breather gas.

(3) Examples An embodiment of the present invention will be described below with reference to the drawings.

Figure 1 is a front view of a V-type two-cylinder internal combustion engine, Figure 2 is a 1t
! A cutaway cross-sectional view along the ■-■ line of I, Figure 3 is the 2nd! !
It is a sectional view taken along the line ■-■ of I.

First, in FIGS. 1 and 2m, in this V-type two-cylinder internal combustion engine, left and right cylinders 2.2 arranged in a V shape are connected to the upper part of a crankcase 1, and a crank A chamber 3 is formed. Further, in the crankcase 1, a crankshaft 4 is rotatably supported, and a camshaft 5, which is interlocked and connected to the crankshaft 4, is rotatably supported in parallel above the crankshaft 4. . The pistons 6.6, which are slidably fitted into each cylinder 2.2, are connected to the crankshaft 4 via the connecting rods 7, 7 with a phase difference of 90 degrees at the crank angle.
connected to.

A bearing hole 8 for supporting one end of the camshaft 5 is bored in the upper part of the crankcase 1, and a cover 9 is provided on the outer surface of the upper part of the crankcase 1 so as to cover the outer end of the bearing hole 8. The outer surface of the crankcase 1 and the cover 9 are fixed to each other.
A breather chamber 10 is defined between the inner surfaces of.

One end of the camshaft 5 is rotatably supported in the bearing hole 8 with its end surface facing outward midway through the bearing hole 8, and the camshaft 5 has one end surface extending in the axial direction. A passage 11' that opens to the camshaft 5 and an opening 12 that communicates with the other end of the passage 11 and opens to the outer surface of the camshaft 5 along the radial direction of the camshaft 50 are formed. The camshaft 5 has suction cylinders disposed corresponding to the pair of cylinders 2.2, respectively.
Two sets of cams 13 each corresponding to an exhaust valve (not shown), that is, four cams 13, are integrally provided with a space between each other, and the openings W&12 are connected to the adjacent pairs of cams 13. ...opens on the outer surface of the camshaft 5 between.

Further, a one-way valve 14 is provided in the crankcase 1 so as to cover the outer end of the bearing hole 8 facing the breather chamber 10 . That is, the one-way valve 14 is interposed between one end of the passage 11 and the breather chamber 10, and opens when the pressure in the passage 11 exceeds a predetermined value to direct the gas in the passage 11 to the breather chamber. Distribution to 10.

Referring also to FIG. 3, the cover 9 that cooperates with the crankcase 1 to form the breather chamber 10 includes a one-way valve 14.
A partition wall 15 is integrally provided to cover the upper part of the breather chamber 10, and a discharge chamber 16 is formed in the upper part of the breather chamber 10 by the partition wall 15. A connecting pipe 17 is attached to the cover 9 with one end protruding into the outlet chamber 16, and a conduit member 18 is attached to the other end of the connecting pipe 17.
One end of the pipe member 18 is connected to the air cleaner 20 , and the other end of the pipe member 18 is connected to the air cleaner 20 via a connecting pipe 19 . Moreover, connecting pipe 1
7 has an axis along one diameter line of the bearing hole 8, and a cover 9
The cover 9 is provided with a communication passage 21 that communicates the breather chamber 10 with the outlet chamber 16 at a position offset from the axis of the connecting pipe 17.

Furthermore, facing the lower part of the breather chamber lO, the crankcase 1
A small-diameter return hole 22 for returning oil accumulated in the lower part of the breather chamber 10 into the crank chamber 3 is bored in the.

Next, the operation of this embodiment will be explained. When the engine is operating, gas in the crank chamber 3 is introduced into the passage 11 from the opening 12 of the camshaft 5, and the pressure in the passage 11 is higher than the pressure in the breather chamber 10. When the one-way valve 14 opens in response to a predetermined value or more, the gas in the passage 11 flows into the breather chamber 10. Since the camshaft 5 is rotating and the opening 12 is along the radial direction of the camshaft 50, the mist entrained in the gas is subjected to centrifugal force when flowing into the passage 11 from the opening 12. Therefore, the excess mist entrained in the gas is suppressed from entering the opening 1B12 due to the action of the centrifugal force, and the gas from which the excess mist has been removed flows from the passage 11 to the one-way valve 14. It is led to the breather chamber 10 through the air.

Moreover, in the breather chamber 10, the gas flows directly to the connecting pipe 17! ! 15 and flows to the right along the partition wall 15 from the communication path 21 to the outlet chamber 1.
6 into the connecting pipe 17 and the conduit member 18, the mist in the gas is removed also in the breather chamber 10, and the oil accumulated in the breather chamber 10 flows from the return hole 22 into the crank chamber. It will be returned within 3.

In this way, the gas in the crank chamber 3 is released to the air cleaner 20 via the reservoir chamber 10 in response to an increase in the pressure in the crank chamber 3.

Therefore, the gas in the crank chamber 3 is released from the part corresponding to the camshaft 5, which is located higher than the crankshaft 4. It can function as a breather from a position where the amount of mist entrained is small.

C1 Effects of the Invention As described above, according to the present invention, a cover that forms a breather chamber between the crankcase and the crankcase is fixed to the outer surface of the crankcase at a position corresponding to one end of the camshaft. is provided with an opening along the radial direction to communicate with the crank chamber, and a passage communicating with the opening and extending toward one end in the axial direction, and a predetermined pressure in the passage is maintained between one end of the passage and the breather chamber. A one-way valve is provided that opens when the temperature exceeds the specified value, and the breather chamber is communicated with an air cleaner, so that the mist entrained in the gas is By applying centrifugal force, the gas from which excess mist has been removed can be released from the passage through the one-way valve and breather chamber to the air cleaner, making it extremely easy to install at a position that is sufficiently high above the oil level in the crank chamber. With this configuration, mist can be removed and the breather function can be demonstrated.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention. ! l
is a front view of a V-type two-cylinder internal combustion engine, and Figure 2 is the same as ■- in Figure 1.
■Cut-out cross-sectional view along the line, 3rd f! l is ■-■ in Figure 2
FIG.

Claims (1)

[Claims] Cylinders (2, 2) are arranged in a V-shape on the left and right in the upper part of the crankcase (1) that forms the crank chamber (3), and the crankshaft (4) and a cam located above the crankshaft (4). The shafts (5) are parallel to each other and the crankcase (1
), the outer surface of the crankcase (1) has a breather chamber (10) between it and the crankcase (1) at a position corresponding to one end of the cam shaft (5). ) is fixed to the camshaft (5) and has an opening (12) along the radial direction of the camshaft (5) to communicate with the crank chamber (3). a passageway (11) extending toward one end in the axial direction;
A one-way valve (14) that opens when the pressure in the passage (11) exceeds a predetermined value is interposed between one end of the passage (11) and the breather chamber (10). 1
0) is a breather device for a V-type internal combustion engine, characterized in that it is communicated with an air cleaner (20).