JPH0514031Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a breather device for a mission chamber in a two-stroke engine.

(Problems to be Solved by the Prior Art and Ideas) Some two-stroke engines have a breather device installed in the mission chamber.

Conventionally, such a breather device is constructed by drilling a hole in the crankcase and attaching one end of the breather pipe to the hole. Even if an attempt is made to remove the member from the crankcase, the member hits the breather pipe, making it difficult to remove, resulting in poor engine maintenance.

On the other hand, it has been desired to reduce the manufacturing process and the manufacturing cost of the engine by optimizing the position of the hole.

The present invention has been developed in view of the above circumstances, and its purpose is to provide a breather device for a mission chamber that is easy to maintain for an engine and can reduce the manufacturing cost of the engine.

(Means for Solving the Problems) In order to achieve the above object, the present invention forms a bulge 30 outward from the crankcase 1, forms a through hole 32 in the bulge 30, Said bulging part 3
0, an intake passage 52 is formed by the intake pipe 40 and the through hole 32, and the intake passage 52 communicates the carburetor 42 with the crank chamber 3 in the crankcase 1. A reed valve 46 consisting of a main body 46a and a valve body 46b is installed in the passage 52.
In the two-stroke engine, the transmission chamber 6 defined by the transmission case 7 adjacent to the crankcase 1 is communicated with outside air via a breather passage 62.
A flange portion 44 is formed at the tip of the reed valve 46, and the flange portion 44 is attached to the main body 46a of the reed valve 46.
A hole 55 is formed through the flange 44, the reed valve body 46a, and the bulge 30 through the flange 44, and a hole 55 is formed in the flange 44 of the hole 55. One end of the breather pipe 57 is fitted and fixed, and the hole 55 and the breather pipe 57 constitute a breather passage 62.

(Function) The flange part of the intake pipe is joined to the bulge formed in the crankcase via the main body of the reed valve,
A hole is formed that passes through the flange, the reed valve body, and the bulge, and one end of the breather pipe is attached to this hole, so when the intake pipe is removed, the breather pipe does not get in the way of the engine. Maintainability can be improved.

Additionally, the holes formed in the bulge are in the same direction as the bolt holes formed in the bulge to attach the reed valve body, so these holes can be machined from the same direction at the same time. This reduces the number of processing steps and reduces engine manufacturing costs.

(Example) An example of the present invention will be described below based on the accompanying drawings.

Figure 1 is a cross-sectional view of a two-stroke engine;
The figure is a longitudinal sectional view of the breather device.

In the figure, 1 is an engine case, and the engine case 1 is a crank case 5 forming a crank chamber 3.
and a mission case 7 forming a mission chamber 6.
A crankshaft 9 is disposed in the crank chamber 3, and a gear transmission mechanism 11 is disposed in the transmission chamber 6.

A cylinder block 13 is attached to the crankcase 15 via bolts 12, a piston 15 is slidably inserted into the cylinder block 13, and the piston 15 and the crankshaft 9 are connected by a connecting rod 17. do. A cylinder head 21 is attached to the upper end of the cylinder block 13 via bolts 19, and the combustion chamber S1 is connected between the cylinder head 21 and the piston 15.
A spark plug 23 attached to a cylinder head 21 faces the combustion chamber S1. Furthermore, an exhaust passage 25 and a scavenging passage 27 are formed in the cylinder block 13, respectively.

On the other hand, a bulge 30 is formed on the wall of the crankcase 15 to face external force, and a through hole 32 is formed in the bulge 30. Further, a breather chamber S2 is formed between the mission chamber 6 and the bulging portion 30, and a portion of this breather chamber S2 extends into a portion of the bulging portion 30. This breather chamber S2 has a wall portion 3.
4 into two chambers S2a and S2b, and further through a gasket 35 these two chambers S2a and S2b are divided into left and right chambers S2a1, S2a2, S2b1 and S2b2. Further, the chambers S2a and S2b communicate with each other through a hole 34a formed in the wall 34, and the mission chamber 6 and the chamber S2a communicate with each other through a hole 36a in the wall 36.

40 is an intake pipe whose one end is connected to the carburetor 42; 46 is a reed valve; the other end of the intake pipe 40 is formed with a flange portion 44; Section 44
b, a hole 46a1 formed in the main body 46a of the reed valve 46, and a hole 30 formed in the bulge 30;
It is attached to the upper surface of the bulge 30 via the reed valve main body 46a with bolts 50 that pass through the reed valve body 46a. The through hole 32 and the intake pipe 40 form an intake passage 52. Note that 46b is a valve body of the reed valve 46.

Holes 30 are provided near the edges of the bulging portion 30, the reed valve body 46a, and the flange portion 44, respectively.
a, 46c, 44a are formed and these holes 30a,
A through hole 55 is formed at 46c and 44a, one end of a breather pipe 57 is fitted and fixed into the hole 44a, and a tube 60 is attached to the other end of the breather pipe 57. The through hole 55 and the breather pipe 5
7. Form a breather passage 62 with a tube 60 or the like.

FIG. 3 shows the top surface of the bulge 30 with the reed valve 46 removed, and as is clear from this figure, the hole 30a forming the breather passage 62 and the hole for attaching the reed valve body 46a. 3
0b... are formed in the same direction and approximately the same diameter.

The interior of the mission chamber 6 is communicated with the atmosphere through the breather chamber S2 and the breather passage 62, and for example, if the temperature of the mission chamber 6 rises, the mission chamber 6
The air flows as shown by the arrow into the chamber S2a1, the holes 35a, S2a2, S2b2 of the gasket 35, the holes 35b and S2b1 of the gasket, and further flows to the outside via the breather passage 62.
When the temperature of the mission chamber 6 decreases, outside air flows into the mission chamber 6, contrary to the above, and the internal pressure within the mission chamber 6 is thereby kept constant. As the air flows through the maze-like passages as shown by the arrow, the oil contained in the air is separated.

In the above, in this embodiment, the end of the breather pipe 57 is fitted and fixed into the hole 44a of the intake pipe flange 44, and the breather pipe 57 and the intake pipe 40 are integrated, so that, for example, the reed valve 46 can be repaired, When the intake pipe 40 is removed for inspection, the breather pipe 57 does not get in the way as in the conventional case, so the intake pipe 40 can be easily removed, and the maintainability of the engine can be improved. .

Further, the hole 30a flange portion 44 for the breather passage 62 formed in the bulging portion 30 is a hole 30b for a bolt for attaching the reed valve body 46a.
..., so both of these holes 30
a and 30b can be machined simultaneously from the same direction, thereby reducing the number of machining steps and reducing the manufacturing cost of the engine.

(Effects of the invention) As described above, according to the invention, a hole is formed that passes through the bulge, the reed valve body, and the intake pipe flange, and the breather pipe is connected to the flange of the hole. Since one end is fitted and fixed, the breather pipe does not get in the way when the intake pipe is removed, making it possible to improve the maintainability of the engine.

In addition, the holes formed in the bulge are in the same direction as the bolt holes formed in the bulge to attach the flange and reed valve body, so these holes must be machined from the same direction at the same time. It is possible to reduce the number of processing steps and reduce the manufacturing cost of the engine.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a two-stroke engine;
The figure is a sectional view taken along the line of FIG. 1, and FIG. 3 is a view showing the upper surface of the bulge with the reed valve removed. In the diagram, 1 is the crank case, 3 is the crank chamber,
6 is the mission room, 7 is the mission case, 30
32 is a through hole, 46 is a reed valve,
46a is the reed valve body, 46b is the same valve body, 5
2 is an intake passage, and 62 is a breather passage.

Claims (1)

[Claims for Utility Model Registration] A bulging portion is formed outward from the crankcase, a through hole is formed in the bulging portion, an intake pipe is attached to the bulging portion, and the intake pipe and the through hole are formed. an intake passage is formed by the hole, the intake passage communicates the carburetor with a crank chamber in the crankcase, and the intake passage is provided with a reed valve consisting of a main body and a valve body, and the reed valve is disposed adjacent to the crankcase. In a two-stroke engine in which a mission chamber defined by a mission case is communicated with outside air through a breather passage, a flange portion is formed at the tip of the intake pipe, and the flange portion is connected through the main body of the reed valve. forming a hole passing through the flange, the reed valve body, and the bulge, and fitting and fixing one end of the breather pipe into the flange of the hole. A breather device for a mission chamber, wherein the hole and the breather pipe constitute a breather passage.