JPH0723539Y2 - Reed valve - Google Patents

Description

TECHNICAL FIELD The present invention relates to a reed valve for a two-cycle engine.

2. Description of the Related Art In a two-cycle engine, gas is allowed to flow from the carburetor to the crankcase, but the gas flow from the crankcase to the carburetor is blocked to prevent gas blowback phenomenon, uneven engine rotation, and reduced fuel consumption. Reed valves are widely used for prevention. In the conventional reed valve 1 (Figs. 10 to 13), a gas flow opening 3 is provided in parallel with a gas flow direction on a surface portion of a valve seat 2 having an inclined surface, and a flexible reed valve is provided in the opening 3. One side and the non-deformable reed valve stopper 5 to the stopper 6
It was installed at. Therefore, when the air-fuel mixture 7 entering the reed valve 1 from the carburetor side flows out from the valve opening 3, the outflow 8 is in the same direction as the air-fuel mixture 7 in the same direction as that of the air-fuel mixture 7 and enters the crankcase. It was flowing.

Further, as shown in FIG. 13, on the crankcase side of the reed valve 1, the cross section of the tip portion of the valve seat 2 is constituted by a flat surface 9 which is substantially perpendicular to the flow direction of the air-fuel mixture.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the conventional reed valve, the gas flow opening 3 is arranged so as to flow out from the carburetor in parallel with the gas flow direction in the crankcase direction at a constant speed. However, in reality, due to the wall resistance of the reed valve and the contraction action of the air-fuel mixture,
The amount of outflow from the opening in the central portion is larger than the amount of outflow from the openings on both wall surfaces, in other words, the air-fuel mixture flows out in a laminar flow from the opening in the central portion, and therefore the reed valve piece 4 provided in the opening. Is completely opened until it comes into contact with the reed valve stopper 5, but the air-fuel mixture passing through the openings on both wall side surfaces causes turbulent flow and eddies. Therefore, the reed valve piece 4 provided in the opening spreads until it comes into contact with the reed valve stopper 5. It was rare. Therefore, the amount of the air-fuel mixture flowing out from the reed valve 1 to the crankcase side is smaller than the design value, and therefore horsepower loss and fuel loss occur.

Further, the tip end face of the valve seat 2 has a cut plane 9 as shown in FIG. Therefore, turbulent air flow was generated at the tip of the flat surface 9. Due to this turbulent air flow, the proper flow of the air-fuel mixture is blocked, and it works synergistically with the valve opening failure.
Horsepower loss and fuel loss were further increasing.

Such a phenomenon is remarkable especially when the engine speed is increased. The present invention solves this problem.

Means for Solving the Problems In order to solve the above problems, in the present invention, all the reed valve pieces provided in the openings of the reed valve are always fully opened equally to increase the intake amount, and the air-fuel mixture reaching each opening is layered. Stream. Therefore, a rectifying plate is provided inside the reed valve.

Furthermore, in order to prevent the mixture from flowing out of the reed valve from generating turbulence in the crankcase and preventing the mixture from flowing in,
The cross section of the tip portion of the reed valve on the crankcase side was constituted by a circular cross-section component.

Function In the present invention, the air-fuel mixture passing through each opening of the reed valve is pre-cured and rectified by the straightening vane, so that the amount of air-fuel mixture passing through each opening is always equal in all the openings, and the air-fuel mixture as designed is Supply is planned.

Further, the mixture flowing at high speed into the crankcase has a circular cross-section at the tip of the reed valve, so that separation from the reed valve is prevented and eddy current generation in the crankcase is prevented.

Embodiment FIG. 1 and FIG. 2 are upper perspective views of a reed valve showing one example embodying the present invention, FIG. 1 is a view from the crankcase side, and FIG. 2 is a view from the carburetor side. It is a figure. The structure of the reed valve 10 is the same as that of the conventional one, the body 12, the reed valve piece 14, the reed valve stopper 16, the reed valve piece 14 and the reed valve stopper.
A stopper 18 for attaching the 16 to the body 12.

The body 12 is generally formed by casting, but is not limited thereto. As shown in FIG. 3, the main body 12 comprises a mounting frame 20 for mounting the reed valve 10 in the engine, and a hollow V-shaped protruding portion 22 having a sloped surface projecting in a V shape in one direction from the frame. . The protrusion
Reference numeral 22 denotes a pair of triangular pieces 26, 26 that horizontally project from the upper and lower transverse pieces 24, 24 of the frame 20, and the directions in which the triangular pieces 26, 26 approach each other from the two sides upward and downward respectively. Slopes 28, 28, 28, 28, which extend to
Blind slopes 32, 32 extending upward and downward from the apex portions 30, 30 of 26, 26, respectively, toward each other.
From the left and right vertical parts 25, 25 of the frame 20 to the slope 28
Triangular side surfaces 34, 34 protruding along the outside of the
Consists of.

On the four slopes 28, 28, 28, 28, the same number (two in the illustrated example) of air-fuel mixture flow openings 36 are provided symmetrically.

A rectifying member 38 is preferably integrally formed inside the protruding portion 22. This member 38 smoothly guides the air-fuel mixture from the carburetor toward the openings 36, 36 without colliding with the inside of the blind slopes 32, 32, and at the same time pre-mixes the mixture so that all the openings are always fully opened. It is for rectifying the air. Rectifying member 38 in this embodiment
Has a generally cruciform shape with vertical fins 38a and horizontal fins 38b so that the air-fuel mixture from the carburetor side is divided into four, but this is not a limitation, and it is subdivided according to the number of openings. It can also be converted. Each of the fins 38a, 38b of the rectifying member 38 of the present invention always has a wing shape from the upstream side to the downstream side, and more preferably, these fins have a retreating wing.

A flexible reed valve piece 14 and a reed valve stopper 16 are attached to the triangular portions 26, 26 of the openings 36, 36 ...

Slopes 28 ... The slopes 32 are sandwiched and arranged in a V shape. This slope 28 ... is a scavenging port (not shown)
It is arranged so as to point to.

FIGS. 4 and 5 show the state of the fins 38a, 38b arranged so that the air-fuel mixture 40 from the carburetor side flows into each opening 36 in a laminar flow by the rectifying fins 38.

Although the embodiment of the present invention describes a specific example in which the two left and right openings 36 are directed outwards, the present invention is not limited to the tenth to twelfth embodiments.
It can also be used for the reed valve of the known shape in the figure.

7 to 9 are views showing the tip shape of the reed valve of the present invention. Although the effect can be sufficiently obtained by using only the straightening vane 38, the effect is further enhanced by making the tip shape into a circular cross-sectional component as shown in these figures.

7 and 8 show the tip shape of the conventional reed valve (see FIG.
(Fig. 13) is improved, and the tip has a predetermined circular cross section. FIG. 9 shows an example in which the tip portion of the current plate 32 has a circular sectional shape in the same manner. Therefore, although this tip shape can be used with the current plate, it can also be used as a single body.

Effect of the Invention In the present invention, the air-fuel mixture from the carburetor side is rectified by the rectification fin when passing through the reed valve. Therefore, the same flow and almost the same amount flow to all the openings, thereby providing a uniform opening of all reed valve pieces. In addition, the air-fuel mixture can be supplied into the crankcase while providing pre-clamping direction as required. The present invention produces effective effects in both the so-called piston lead system and the case lead system.

FIG. 6 is a diagram showing the relationship between the rotational speed and the output horsepower measured using the RS125R88 model engine. The broken line shows the case where the reed valve of the present case is used, and the solid line shows the case where a known reed valve is used. As can be seen from this experimental graph, the reed valve of the present invention is particularly effective when the rotation speed becomes high. This is an effect due to an increase in scavenging efficiency and intake efficiency.

Furthermore, since the tip of the reed valve has a circular cross section, as shown in Fig. 13, swirl of the air-fuel mixture in the crankcase at the tip of the reed valve is prevented, and as a result, the air-fuel mixture is rectified and quickly and always smoothly. Only a certain amount of gas flows into the crankcase, which results in increased scavenging and intake efficiency in a two-cycle engine.

[Brief description of drawings]

1 is a front view of the reed valve of the present invention, FIG. 2 is a rear view of the reed valve of the present invention, FIG. 3 is an explanatory view of the reed valve of the present invention, and FIGS. 4 and 5 are of the present invention. FIG. 6 is a view showing the arrangement of rectifying fins in a reed valve, FIG. 6 is a performance comparison graph of the reed valve of the present invention and a known reed valve, and FIGS. 7, 8 and 9 are reed valves according to the present invention. FIG. 10 is a view showing a tip shape, FIG. 10 is a top view of a known reed valve, FIG. 11 is a XI-XI arrow view of FIG. 10, and FIG.
1 is a view similar to FIG. 1, in which the reed valve piece on the upper slope is closed and the reed valve piece on the lower slope is open, and FIG. 13 is an enlarged view of the tip of a known reed valve. Explanation of symbols 10: Reed valve, 12: Main body 14: Reed valve piece 16: Reed valve stopper 18: Stopper, 20: Frame 22: V-shaped protrusion, 24: Horizontal piece 25: Vertical piece, 26: Triangular piece 28: Slope, 30: Apex part 32: Blind slope, 34: Side surface 36: Opening, 38: Rectifying member 40: Mixture

Claims (2)

[Scope of utility model registration request] 1. A projection projecting toward the crankcase from an attachment frame 20 having a pair of transverse part pieces 24 and a pair of longitudinal part pieces 25 connecting both ends of the transverse part pieces 24. Department
A reed valve (10) is provided with a plurality of openings (36) provided on a wall surface of a reed valve piece (14) that opens only to the crankcase side. A pair of triangular pieces
26 and 26, and slopes 28 and 2 extending from the two sides of the triangular parts 26 and 26 toward the upper side and the lower side respectively.
8, 28, 28, blind slopes 32, 32 extending from the apex portions 30, 30 of the triangular parts 26, 26 toward the upper side and the lower side, respectively, and the vertical part 25, 25 and triangular side surfaces 34, 34 protruding along the outside of the slope 28, and the slopes 28, 28, 28, 28 on the left and right sides of the upper and lower blind slopes 32, 32, respectively. Faced in the direction away from each other from the blind slope, the same number of air-fuel mixture flow openings 36 are provided symmetrically on the slope, and the air-fuel mixture flowing from the carburetor side is provided in the protrusion 22. A reed valve having a rectifying member (38) in which fins for rectifying the slopes (28, 28, 28, 28) are arranged in a substantially cross shape. 2. The front abutting edges of the upper, lower, left and right slopes 28 and the front abutting edges of the upper and lower blind slopes 32, 32 are substantially horizontal to the pair of transverse members 24 and these transverse members 24. 2. The reed valve according to claim 1, wherein the reed valve is arranged at a substantially central position between No. 24 and No. 24, and their front abutting edges are constituted by circular cross-section components.