JP3024334B2 - Reed valve for two-stroke engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reed valve of a two-cycle engine.

[0002]

2. Description of the Related Art In a scooter type motorcycle as shown in FIG. 4, a two-cycle engine is used as an engine 1, and a rear wheel is provided at a rear portion of a power unit 4 which is swingably connected to a body frame 2 by pins 3. 5 is supported, and the rotation of the engine 1 is transmitted to the rear wheels 5 through a transmission mechanism in the power unit 4 so that the vehicle runs.
The engine 1 is provided with an air cleaner 6, a carburetor 7, an ignition coil 8, an oil pump 9, and the like. In the figure, 10 is a rear shock unit that supports the power unit 4, 11 is a storage room, 12 is a gas tank,
Reference numeral 13 denotes an oil tank.

In such a two-cycle engine, FIG.
As shown in the figure, a reed valve 15 is incorporated in the intake system from the air cleaner 6 to the intake port 14 of the engine 1 through the carburetor 7, and the reed valve 15 is opened at the time of intake to take in the engine 1, and the lead is provided except at the time of intake. Valve 15
Is closed to prevent backflow.

As shown in FIG. 6, the reed valve 15 is generally formed so that a passage 17 in a reed valve main body 16 is substantially straight without being bent. In the case of bending, the passage 17 is formed integrally with the reed valve main body 16 (FIG. 7) or by attaching a separate part 18 as shown in FIG.

[0005]

However, in the conventional reed valve, when the storage chamber 11 provided in the vehicle body and the carburetor 7 interfere with each other, the intake passage is formed by the intake pipe 19 and the mounting surface of the reed valve 15 on the vehicle body layout. As shown in FIG. 8, there is a case where the air-fuel mixture bends or bends extremely sharply. In such a case, the air-fuel mixture may not flow smoothly when the engine 1 is running at a low speed, particularly when idling, so that the rotation speed may fluctuate. And the rotation becomes unstable.

The intake passage 17 is connected to the reed valve main body 16.
If it is bent or bent integrally with the mold, the mold splitting position comes to the approximate center of the passage 17 as shown by aa in FIG. 7, and it is difficult to remove burrs at the time of molding generated at this portion. Become.

Further, as shown in FIG. 8, when a separate part 18 is incorporated into the reed valve main body 16 to form the passage 17, the separate part 18 is located between the reed valve main body 16 and the mounting surface 18 a of the reed valve main body 16 to the intake pipe 19. If there is a gap,
When the air-fuel mixture is liquefied, gasoline easily accumulates in the gap 20, and when such gasoline accumulates, the amount of air decreases when the engine 1 rotates at a low speed. , Causing a situation in which the engine may become too rich and cause engine stall.

However, when assembling the separate part 18 into the reed valve body 16, if the milling cutter 21 attempts to machine the step so that no step is formed between the separate part 18 and the mounting surface 16 a of the reed valve body 16, the cutting resistance is reduced. As a result, the separate part 18 of the passage 17 easily rises as shown by a two-dot chain line in FIG. There is also a method of sealing by gaskets or the like without processing. However, if the diameter of the screw for attaching the reed valve body 16 to the intake pipe 19 is small and the tightening torque is low, the reliability of the seal is lacking. Become. In each of the drawings, reference numeral 22 denotes a reed valve.

An object of the present invention is to provide a reed valve for a two-stroke engine that can be easily assembled, has high sealing properties, and can solve all of the problems of the prior art.

[0010]

In order to achieve the above object, according to the present invention, a seal plug made of an elastic material is buried in an intake pipe mounting surface of another part which is incorporated in a reed valve main body and constitutes a passage. The plug is formed in a suction cup shape by projecting a peripheral portion of an intake pipe mounting surface from a central portion.

[0011]

[Action] When the reed valve body is joined to the mounting surface of the intake pipe and mounted with screws, the peripheral part of the seal plug on the mounting surface of another part is tightly attached to the joining surface of the intake pipe and tightened, eliminating gaps. Liquefied gasoline is prevented from entering. Also, even if there is a step on the mounting surface between the reed valve body and another component, the adhesion is maintained by the amount of deflection of the suction cup-shaped peripheral portion of the seal plug, and the management of the mounting position of the separate component becomes easy.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

FIG. 1 is a perspective view of the reed valve, and FIG. 2 is a sectional view taken along line AA of FIG. 1. The reed valve body 23 is a molded product made of aluminum or the like.
2 has an inclined reed valve mounting surface 24 for mounting
A passage 25 is formed inside, and a hole 26 communicating with the passage 25 is opened and closed by a free end of the reed valve 22. One inner surface of this passage 25 is formed by one side surface 27 b of another component 27 incorporated in the reed valve main body 23.

A seal plug 28 made of an elastic material such as rubber is fitted in a mounting surface 27a of the separate component 27 to the intake pipe 19. The upper surface of the seal plug 28 is dish-shaped, and its peripheral portion 29 extends outward and protrudes upward from the mounting surface 27a. The peripheral portion 29 is bent by an external force and has a suction cup structure. I have. Attachment of this seal plug 28 to another component 27
The projections 30, 30 projecting from the three side surfaces of the separate component 27 are fixed by press-fitting the grooves 31, 31,. The mounting surface 27a on which the seal plug 28 is located is lower than the mounting surface 33a of the reed valve main body 23 by H, and the peripheral portion 29 of the seal plug 28 is assembled so as to slightly protrude from the mounting surface 23a. In the figure, 32, 32 are holes for screwing.

Therefore, when the reed valve main body 23 is fastened to the intake pipe 19 by screws passing through the holes 32, the peripheral portion 29 of the seal plug 28 comes into contact with the joining surface of the intake pipe 19 first, and the peripheral portion 29 is fastened by tightening. The part 29 is pressed and adheres, and a sealing state is established. Thus, even if the mounting surface 27a of the separate component 27 is lower than the mounting surface 23a of the reed valve body 23, the sealing is reliably performed, and the liquefied gasoline does not enter.

FIG. 3 shows another example of the shape of the inner surface 27b of the separate part 27 when the passage 25 is curved.
The inner surface on the side of the reed valve main body 23 facing the curved surface 27b of the separate component 27 may also be a curved surface corresponding to the curved surface 27b.

[0017]

As described above, according to the present invention, there is provided a reed valve in which a separate component is assembled into a reed valve main body to constitute a passage. Even if it does not adhere to the joint surface of the part, the peripheral part of the seal plug embedded in the mounting surface of another part closely adheres to the joint surface of the intake pipe and maintains a sealed state, so that liquefied gasoline does not enter the gap , At low speed,
In particular, the mixture does not become excessively concentrated during idling.
Further, even if the tightening torque at the time of mounting the reed valve is small, the seal can be reliably achieved. In this way, the passage can be easily formed by assembling the separate parts, so that the mold structure for forming the reed valve is simplified, and the need for deburring is eliminated, thereby facilitating the manufacture. In addition, it is possible to easily manufacture even a passage structure having a large degree of freedom in the shape of the passage and having a large bend or curve, and it is easy to obtain an efficient reed valve.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a reed valve of a two-cycle engine according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view showing another embodiment of the reed valve of the two-stroke engine of the present invention.

FIG. 4 is a side view showing a motorcycle equipped with a two-cycle engine to which the present invention is applied.

FIG. 5 is a sectional view showing an intake system of the two-stroke engine of FIG. 4;

FIG. 6 is a side view showing a general reed valve.

FIG. 7 is an enlarged view showing a cross-sectional structure of a conventional reed valve.

FIG. 8 is a cross-sectional view of a reed valve that forms a passage by incorporating another component.

FIG. 9 is a cross-sectional view showing a defect when the mounting surface of a conventional reed valve is finished by cutting.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Body frame 4 Engine unit 6 Air cleaner 16 Reed valve main body 17 Passage 18 Separate part 19 Intake pipe 23 Reed valve main body 24 Reed valve mounting surface 25 Passage 27 Separate part 28 Seal plug 29 Peripheral part 30 Projection 31 Groove

Claims (1)

(57) [Claims] 1. A reed valve for a two-stroke engine having a structure in which a separate part is incorporated into a reed valve body to form a passage. A seal plug made of an elastic material is provided on an intake pipe mounting surface of another part incorporated in the reed valve body. A reed valve for a two-stroke engine, wherein the seal plug is formed in a suction cup shape by protruding a peripheral portion of an intake pipe mounting surface of the seal plug from a central portion.