JPH0442229Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a breather device that communicates the crankcase of an engine in an all-terrain vehicle with the atmosphere.

(Background of the idea) Wide ultra-low pressure tires (so-called balloon tires)
Conventionally, there are two-, three-, and four-wheeled vehicles equipped with a vehicle for traveling on rough terrain. Some vehicles of this type have a breather pipe that opens directly to the atmosphere to allow blow-by gas in the engine crankcase to escape to the atmosphere. In this case, in a vehicle for traveling on rough terrain, sand or mud may adhere to and solidify at the atmosphere side opening of the breather pipe while the vehicle is running, thereby blocking the atmosphere side opening. Furthermore, when driving in a cold region, water splashed up by the vehicle or moisture contained in blow-by gas may freeze in the atmosphere-side opening, causing the atmosphere-side opening to become clogged.

If the breather pipe is blocked in this way, the internal pressure of the crankcase will rise excessively, causing a drop in engine output, and sealing members such as plugs attached to the crankcase or crankcase cover may fall off. arise.

Therefore, conventionally, the breather pipe does not open directly to the atmosphere, but instead opens into the intake system of the engine, such as in an air cleaner. However, in this case, a problem arises in that fluctuations in the internal pressure of the crankcase affect the carburetor, making it difficult to adjust the carburetor.

In addition, the breather pipe is bifurcated so that no inconvenience occurs even if one opening on the atmosphere side is blocked, and a relief valve is installed in the middle of the breather pipe to allow blow-by gas to flow to the atmosphere side. There is something set up. However, in this case, the problem arises that the number of parts increases and assembly becomes troublesome.

(Purpose of the invention) The present invention was developed in view of these circumstances, and even though the breather pipe opens directly to the atmosphere, there is a risk that the internal pressure in the crankcase will become excessive even if the opening on the atmosphere side is blocked. The structure is simple, and the number of parts does not increase at all. The purpose of the present invention is to provide a breather device for a vehicle for traveling on rough terrain.

(Structure of the invention) According to the invention, this purpose is to provide an uneven terrain vehicle equipped with wheels with wide ultra-low pressure tires, an engine mounted near the center of the vehicle body, and a straddle-type driver seat attached to the upper part of the vehicle body. A running vehicle is provided with a breather pipe having one end connected to the crankcase of the engine and the other end opening directly to the atmosphere at a position higher than the crankcase, and the breather pipe has a cut at a position higher than the crankcase. This is achieved by a breather device for an all-terrain vehicle, characterized in that the cut is opened when the pressure difference between the inside and outside increases due to the blockage of the atmospheric side opening of the breather pipe.

(Embodiment) FIG. 1 is a partially sectional side view of an embodiment of the present invention, and FIG. 2 is an enlarged side view of the main parts thereof.

In these figures, reference numeral 10 is a vehicle body frame, 12 is a pair of left and right steering front wheels, and 14 is a pair of left and right driving rear wheels.
4 is equipped with wide, ultra-low-pressure tires. 16
is the engine, which is mounted near the center of the vehicle body. 18 is a vaporizer. The vehicle body frame 10
is the main tube 10 located above the engine 16
A steering shaft holding portion 22 that rotatably holds the upper portion of the steering shaft 20 is fixed to the front end of the main tube 10a. A steering bar handle 24 is fixed to the upper end of the steering shaft 20, and its rotation causes the front wheels 12 to rotate left and right. 26 is main tube 1
Fuel tank installed so as to straddle 0a, 2
Reference numeral 8 denotes a straddle-type driver's seat that extends rearward and is located at the top of the vehicle body so as to be continuous with the fuel tank 26. Further, 30 is a front fender, and 32 is a rear fender.

34 is a breather pipe. One end of this breather pipe 34 is connected to the upper surface of the crankcase 16a of the engine 16 and
It communicates with a. The breather pipe 34 rises upward from the crankcase 16a and extends forward and upward along the main tube 10a. The front end portion thereof is inserted into a ring member 36 fixed to the side surface of the steering shaft holding portion 22, and the atmosphere side opening 34
a is directed forward and downward. Reference numerals 38 and 38 are bands that hold this breather pipe 34 to the main tube 10a.

This breather pipe 34 is made of an elastic material.
For example, it is made of rubber or the like, and as shown in FIG. 2, a long cut 40 is formed in the longitudinal direction of the breather pipe 34 on its side surface. This cut 40 is
While the atmosphere side opening 34a is open, it is closed due to the elasticity of the breather pipe 34 itself. When sand, mud, ice, etc. adhere to the atmosphere side opening 34a and the atmosphere side opening 34a is blocked, the pressure difference between the inside of the breather pipe 34 and the atmosphere, that is, the pressure difference between the inside and outside of the breather pipe 34 increases. The cut 40 is automatically pushed open by this pressure difference. Therefore, the internal pressure of the crankcase 16a does not become excessive.

Note that since the blow-by gas flowing from the crankcase 16a into the breather pipe 34 contains droplets of lubricating oil, etc., the lubricating oil adheres to the inner surface of the breather pipe 34 on the crankcase 16a side. Therefore, the cut 40 is of course provided at a position higher than the crankcase 16a, but it is desirable to provide it at a position as high as possible and as far as possible from the crankcase 16a.
In this way, the amount of lubricating oil seeping out from the cut 40 is reduced.

(Effects of the Invention) As described above, in the present invention, a cut is formed in the breather pipe at a higher position than the crankcase, and the atmosphere side opening of the breather pipe is arranged at a higher position than the crankcase. Therefore, if sand, mud, or ice sticks to the atmosphere side opening of the breather pipe and the internal pressure of the crankcase increases, the cut will open automatically.
The crankcase internal pressure does not become excessive. Furthermore, since it is sufficient to simply form a cut, the number of parts does not increase and the configuration is simple. Furthermore, since the atmosphere-side opening and the break are located at a higher position than the crankcase, there is also the effect that water is less likely to enter the breather pipe even when traveling on water.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional side view of an embodiment of the present invention, and FIG. 2 is an enlarged side view of the main parts thereof. 12... Front wheel, 14... Rear wheel, 16... Engine, 16a... Crank case, 28... Straddle type driving seat, 34... Breather pipe, 34a...
...Atmospheric side opening, 40...cut.

Claims (1)

[Scope of Claim for Utility Model Registration] An off-road vehicle equipped with wheels with wide ultra-low-pressure tires, an engine mounted near the center of the vehicle body, and a straddle-type driver seat attached to the top of the vehicle body. is connected to the crankcase of the engine, and has a breather pipe whose other end opens directly to the atmosphere at a position higher than the crankcase, and a cut is formed in the breather pipe at a position higher than the crankcase, and the breather pipe A breather device for a vehicle traveling on rough terrain, characterized in that the cut is opened when the difference in internal and external pressure increases due to blockage of the atmospheric side opening of the vehicle.