JPS6337450Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a crankcase for ventilating the inside of an engine, and particularly relates to an end structure of a breather pipe.

(Prior Art) Conventionally, this type of breather pipe is known, for example, as described in Japanese Utility Model Publication No. 43-4012. According to this, the open end of the breather pipe (internal ventilation pipe) on the side opposite to the crankcase faces upward.

(Problem to be solved by the invention) However, when an engine equipped with a breather pipe having such a configuration is mounted on a motorcycle, particularly an off-road motorcycle such as a motocross motorcycle, water droplets may be sucked into the crank chamber while driving in a puddle. This can easily lead to deterioration of the bearing due to deterioration of the lubricating oil or poor clutch connection. Furthermore, when the inside of the crankcase becomes negative pressure due to rapid cooling of the engine, etc., water droplets adhering to the open end side of the breather pipe are likely to be sucked into the inside.

As a countermeasure for this problem, for example, it is possible to make the opening end of the breather pipe on the side opposite to the crankcase face the horizontal direction, or to form the opening end into an elliptical shape.

However, if the former configuration (the opening end faces horizontally) is applied to a motorcycle for off-road driving as described above, the engine will be placed close to the front or rear wheels. Therefore, it is difficult to prevent water mud that is scattered by the front wheels and the rear wheels, especially that having a velocity component in the horizontal direction, from entering the crankcase. Also,
Water droplets adhering to the vicinity of the opening end are not drained well, and it is also difficult to prevent water from entering the crankcase. On the other hand, in the case of using only the latter configuration (a configuration in which the open end is formed in an elliptical shape), if the open end is covered with a film of water, it is impossible to avoid water being sucked in by the negative pressure within the crankcase.

Furthermore, a configuration in which a predetermined cap with a narrowed opening is attached to the open end of the breather pipe may be considered, but this is undesirable as it increases the cost.

The present invention has been made to solve the problems of the prior art, and aims to provide an end structure of a breather pipe that can effectively prevent water from being sucked in from the open end with a simple configuration. .

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a breather pipe for ventilating the inside of the crankcase of an engine, in which the end portion of the breather pipe on the side opposite to the crankcase extends downward. The breather pipe is characterized in that an open end with a step in the axial direction of the breather pipe is formed at the distal end, and a slit is provided along the axial direction with the lower end located at the position where the step is formed.

(Function) Since the end portion of the breather pipe on the side opposite to the crankcase extends downward, there is no possibility that water droplets scattered by the front and rear wheels, etc. will infiltrate into the crankcase through the breather pipe. Further, even if the end side is submerged in water up to the step position of the open end, air will be sucked into the crankcase because the slit is formed, but water will not be sucked in.

(Example) As shown in FIG. 2, a motorcycle 1 to which the present invention is applied is, for example, a motorcycle for off-road driving, and an engine 4 mounted approximately in the center of a frame 3 behind a front wheel 2 is a chain. 5 to drive the rear wheels 6. One end 8 of the breather pipe 7 is connected to the crankcase 9 of the engine 4 so as to communicate with the crank chamber, and the other end (terminus) 10 extends downward to the lower end surface of the engine 4.

As shown in FIG. 1, the breather pipe 7 is made of a flexible material such as vinyl, and the end portion 10 is cut in half, and this cut creates a step in the axial direction of the breather pipe 7. Two open ends 11 and 12 are formed. Further, two slits 13 and 14 having a predetermined length are formed in the distal end portion 10 so as to extend along the axial direction from the open end 11 located above the open end 12 and to face each other. There is. In other words, both slits 13 and 14
The lower ends 15, 16 of are located above the open end 12.

With this structure, the end portion 10 of the breather pipe 7 is exposed to the atmosphere below the engine 4, so that blow-by gas and the like in the crankcase 9 can be exhausted and ventilation can be easily performed. .

On the other hand, even if the end portion 10 of the breather pipe 7 is submerged in water and the open ends 11 and 12 are closed due to, for example, driving the motorcycle 1 through a puddle, the slits 13 and 14 are exposed to the atmosphere. from,
Water is not sucked into the crankcase 9.

Furthermore, even if water droplets adhering to the breather pipe 7 flow down to the end portion 10 due to water splashing from the front wheels 2, rear wheels 6, etc. while driving, the opening end 11 and the opening end 12 are connected to the axis of the breather pipe 7. Since there is a step in the direction, the open part formed between the opening end 12 will not be blocked by the water that has flowed down, and only air will be sucked in from the open part.

In addition, in the above embodiment, the slits 13 and 14 are 2
Although it was formed into a row, it is also possible to use just one row.

(Effects of the invention) As described above, according to the invention, in the breather pipe that ventilates the inside of the engine crankcase, the end portion of the breather pipe on the side opposite to the crankcase extends downward, and the end portion While the opening end of the breather pipe is stepped in the axial direction, the lower end is located at the position where the step is formed, and a slit is provided along the axial direction. It is difficult for water droplets to enter the end of the side, and even if the open end of the end is immersed in a puddle of water, only air is sucked into the breather pipe through the slit, creating negative pressure in the crankcase. Even if this occurs, there is no risk of water being sucked into the crankcase. In addition, since the opening end is formed with a step,
Even if the breather pipe flows down and water drops concentrate on the opening end, the water drains well and only air is sucked in.
No water is sucked into the crankcase. Moreover, it is possible to avoid high costs because it is only necessary to perform simple processing on the end portion of the breather pipe.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the end structure of a breather pipe according to the present invention, and FIG. 2 is a side view of a motorcycle equipped with the breather pipe shown in FIG. 1. 4...engine, 7...breather pipe, 9...
... Crank case, 10 ... End part, 11, 12
...Open end, 13,14...Slit, 15,1
6...The end of the slit.

Claims (1)

[Scope of utility model registration request] In a breather pipe for ventilating the inside of a crankcase of an engine, an end portion of the breather pipe on the side opposite to the crankcase extends downward, and an open end forming a step in the axial direction of the breather pipe is formed at the end portion. An end structure of a breather pipe, characterized in that a lower end is located at a position where the step is formed, and a slit is provided along the axial direction.