JPS5928090Y2 - Reed valve device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a reed valve device for a two-stroke engine.

FIG. 1 is a cross-sectional view showing the main parts of an engine equipped with a conventional reed valve device of this type, and FIG. 2 is a cross-sectional view taken along the arrows XX in FIG.

The cylindrical flange 1 projects laterally from the bottom of the crankcase 2 and extends slightly downward from the crankcase 2, and its bottom surface is connected to the bottom of the inner surface 4 of the crankcase via a gently curved surface 3. There is.

The valve seat 6 of the reed valve 5 is generally roof-shaped, but is provided with a cutout surface 9 extending along the circumscribed circle 8 of the crank web 7 at a slight interval.

The valve seat 6 has a cutout surface 10 below the point A and has a shape that roughly follows the curved surface 3.

On the meat slanted wall of the valve seat 6, which is slightly narrowed by the notch surface 9,
An asymmetrical intake hole 11 is formed along the contour, and an asymmetrical valve 13 is attached with bolts 12 so as to cover this intake hole 11.

The bolt 12 fixes the valve 13 to the valve seat 6 at the left edge of the intake hole 11, that is, the edge on the large diameter side of the valve seat 6.

In FIG. 2, 14 is a stopper, and B is the center surface of an inclined wall forming two valve seat surfaces of the valve seat 6, which is orthogonal to the crankshaft.

When the piston attached to the upper end of the connecting rod 15 rises during engine operation, the pressure in the crank chamber 16 decreases, the valve 13 opens, and the air (intake) to which fuel has been added in the carburetor 17 flows into the reed valve 5. It is introduced into the crank chamber 16 from the cavity through the intake hole 11.

Since the center surface B of the reed valve 5 is perpendicular to the center O of the crankshaft and occupies the center position of the two crank webs 7.7, the valve 13 is pushed open from the intake hole 11 and the crankshaft is opened. The intake air flowing out to the chamber 16 side enters the crank chamber 16 through the gap between the crank webs 7.7 without colliding with both crank webs 7.7, as shown by the arrows in FIG.

The conventional type mentioned above had the following problems.In order to reduce the lateral protrusion of the carburetor, the part of the reed valve that interferes with the crank web is cut out, which inevitably reduces the intake air flow. Since the flow path area is sacrificed, the flow path resistance increases and the high-speed performance of the engine decreases.

Moreover, stable output performance over a wide range of rotational speeds could not be obtained.

The purpose of this invention is to focus on the above points, and to increase the preload ratio in the crank chamber by increasing the preload ratio in the crank chamber by increasing the proximity of the reed valve's crank web without sacrificing the intake air flow path area. The purpose of the present invention is to provide a valve device, and its characteristics are that it is a glued valve in the shape of a polygonal pyramid, and that a valve is provided on each side of the polygonal pyramid, and that the valve device is placed as close as possible to the crank web. This is because the internal volume of the case has been reduced.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 is a sectional view showing the main parts of an engine equipped with the first embodiment of the reed valve device according to the present invention, and FIG. 4 is the I of FIG.
It is a sectional view taken along the V-TV arrow.

The differences from the conventional one will be explained.

As shown in FIG. 4, the valve body 20 of the reed valve device is formed in the shape of a triangular pyramid with a triangular cross section, and has an opening at the bottom that communicates with the intake passage from the carburetor. A valve seat 21 is formed with an opening or intake hole 24 therein.

In addition, the ridge line C is the crank web 7 in the crankshaft direction.
．． 7, and is also close to the locus 22 of the connecting rod 15 with a slight gap.

Reference numeral 23 denotes a symmetrical valve, which is attached to the base of the valve seat 21 by bolts 12 so as to cover the intake holes 24 on three surfaces of the valve body 20, respectively.

Although not shown, the height of the stopper can be set arbitrarily.

The operation in the case of the above configuration will be described.

During engine operation, when the piston rises, crank chamber 1
6, the valve 23 opens, and the intake air flows through each intake hole 2.
4 into the crank chamber 16.

At this time, since the reed valve consisting of the valve body 20 and the valve 23 is located in the middle of the crank web and close to the trajectory of the connecting rod 15 as described above, the valve 23 is pushed open from the intake hole 24 and the reed valve is inserted into the crank chamber. The intake air flowing out to the 16 side enters the crank chamber 16 through the gap between the crank webs 7.7 without colliding with both crank webs 7.7.

The present invention as described above has the following effects.

The valve body 20 is formed into a triangular pyramid shape, and the valves 23 are provided on each side of the triangular pyramid to be placed as close as possible to the crank web 7, so that the space for accommodating the reed valve is small and compact. , it is possible to maintain a large preload ratio, and the flow path resistance can be reduced as much as possible without sacrificing the intake air flow path area.

Therefore, an improvement in engine output and high-speed performance is achieved.

Furthermore, stable output performance can be maintained over a wide range of rotational speeds.

5 and 6 show a second embodiment of the present invention, in which a square pyramid shaped valve body 30 is used instead of a triangular pyramid shape.

7 and 8 show a third embodiment of the present invention, in which a triangular pyramid-shaped valve body 4 is oriented in the opposite direction to that of the first embodiment.
0 is set.

FIG. 9 shows a fourth embodiment of the present invention, which is a modification of the first embodiment, in which a valve body 50 of a triangular pyramid having two asymmetrical shapes is provided.

Each of these embodiments provides the same functions and effects as the first embodiment.

Moreover, it goes without saying that the structure is not limited to a triangular pyramid or a square pyramid, and similar functions and effects can be obtained if a polygonal pyramid is used.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the main parts of an engine equipped with a conventional reed valve device, Fig. 2 is a sectional view taken along the ■-■ arrow in Fig. 1, and Fig. 3 is a device of the first embodiment according to the present invention. FIG. 4 is a sectional view taken along the line IV-IV in FIG. 6 is a sectional view taken along the line Vl-VI in FIG.
The figure is a cross-sectional view taken along the line ■--■ in FIG. 7, and FIG. 9 is a cross-sectional view showing the main parts of an engine equipped with a fourth embodiment of the device according to the present invention. 7...Crank web, 12...Bolt, 15...Connecting rod, 16...
...Crank chamber, 20.30,40,50...
... Valve body, 21 ... Valve seat, 23 ...
Valve, 24...Intake hole.

Claims (1)

[Scope of utility model registration request] In the reed valve device of a 2-cycle engine, which is attached to a cylindrical flange that protrudes laterally from the bottom of the crankcase at the middle of both crank webs, it is a hollow polygonal pyramid with a communication port for the carburetor on the bottom. A valve body having an opening on each inclined surface of the same polygonal pyramidal portion, a valve provided at the opening of each inclined surface to open and close the opening, a connecting rod when the crankshaft rotates, and crank webs on both sides. A reed valve device comprising: the above-mentioned valve body with a small gap maintained therebetween; and a distal end portion of the valve facing the above-mentioned crankshaft.