JPH0310441Y2 - - Google Patents

Description

[Detailed explanation of the invention] [Purpose of the invention] (Field of industrial application)
The present invention relates to a reed valve device for a cycle engine.

(Prior Art) As shown in FIGS. 1 and 2, a reed valve device for a two-stroke engine has a valve seat 3 formed on the outer peripheral surface of a valve port 2 provided in a body 1, and a proximal end formed on the body 1. Reed valve 4 stuck to 1
A reed valve assembly is constructed by bringing the reed valve into elastic contact with the valve seat 3 by its own elasticity, and it is common to insert this reed valve assembly at a suitable position in the intake hole. Due to the lift of the reed valve 4, the flow of intake air concentrates more at the tip of the valve opening (arrow), as shown in FIG.

In order to increase the intake efficiency of the engine, it is necessary to widen the valve port 2 of this reed valve device.
In this case, since the reed valve 4 is made of a thin plate, if the valve port 2 is wide, it cannot withstand the crank chamber pressure. For this reason, as shown in FIG. 1, a seat rib 5 is arranged on the valve port 2, and a dividing line 6 is placed along the seat rib 5 on the reed valve 4, so that a plurality of reed valve devices are arranged in parallel. . The reason for inserting the dividing line 6 is that the intake flow at each divided valve port becomes uneven due to the division by the seat rib 5, and with a single reed valve, the opening and closing operation is distorted, making it difficult to operate smoothly. This is to prevent the valve action from being impaired.

However, in the reed valve device with the above structure,
The presence of the seat ribs increases flow resistance and reduces intake air filling efficiency. Furthermore, reed valves provided with score lines require advanced processing techniques and are expensive.

(Problems to be solved by the invention) This invention was made in view of the above points, and it reduces the number of seat ribs, allows a single reed valve to function without any obstruction, and improves intake air filling efficiency and workability. An object of the present invention is to provide an improved reed valve device for a two-stroke engine.

[Structure of the idea]

(Means for Solving the Problems) In accordance with the above object, the reed valve device for a two-stroke engine of this invention is a reed valve whose base end is fixed to a valve seat on the outer peripheral surface of a valve port and whose tip is a free end. In a reed valve device in which the reed valve free end side opening width of the valve port is made wider than the front and rear width, and the proximal edge and between both side edges excluding the free end side opening edge of the valve port. A seat rib is formed across the valve, and one wide reed valve is elastically installed at this wide valve opening.

(Function) With the above configuration, since there is no seat rib at the tip of the valve port through which the main flow of intake air passes, the intake air filling efficiency is improved. In addition, there is less variation in the intake air flow, and the reed valve operates smoothly using a single wide plate, reducing manufacturing costs.

(Example) Hereinafter, an example of the reed valve device for a two-stroke engine according to this invention will be described with reference to FIG. 3.

FIG. 3 shows an example of the reed valve device for a two-stroke engine of this invention. This reed valve device has a wide valve port 8 opened in a body 7, and a valve seat 9 whose outer peripheral surface is processed to be smooth.
is formed. Further, for example, a V-shaped seat rib 10 is formed from the center of the proximal edge 8a of the valve port 8 to the distal edge 8c at the center of both side edges 8b, and its outer surface is also finished flush with the surface of the valve seat 9.

The reed valve 11 is formed as one wide continuous plate, and its base end is fixed to the body 7, and its peripheral edge is brought into elastic contact with the valve seat 9 by its own elasticity. It also contacts the seat rib 10. The tip becomes a free end.

The thus assembled reed valve device is installed in the intake passage of a two-stroke engine.

The negative pressure in the crank chamber pushes up the tip of the reed valve 11, opens the valve port 8, and introduces intake air into the crank chamber. Therefore, the main flow of intake air passes through the tip of the valve port 8. That is, most of the intake air flow gathers at the tip of the valve port within a range of approximately 1/4 length from the tip edge 8c. When the crank chamber becomes positive pressure, reed valve 11
is in contact with the valve port 8 to prevent backflow. By repeating the above action, the intake air of the two-stroke engine is automatically controlled according to the vertical movement of the piston.

[Effect of idea]

As described above, the reed valve device for a two-stroke engine according to this invention is a reed valve device in which a reed valve whose base end is fixed and whose tip end is a free end is brought into elastic contact with the valve seat on the outer peripheral surface of the valve port. , the width of the reed valve free end side opening of the valve port is made wider than the front and back width, and a seat rib is formed that crosses the proximal edge and both side edges excluding the free end side opening edge of the valve port; A wide reed valve is installed in a wide valve opening, and since the main flow of intake air gathers at the tip, it flows without resistance in this part where there is no seat rib, improving intake air filling efficiency.
The reed valve is supported by the seat rib and sufficiently withstands the pressure inside the crank chamber, allowing the use of a single wide plate. Therefore, processing of the reed valve is easy, and productivity and cost are improved. This has the effect of reducing costs and improving engine output performance.

[Brief explanation of the drawing]

Fig. 1 is a plan view of a conventional reed valve device, Fig. 2 is a longitudinal cross-sectional side view taken along arrow A-A in Fig. 1, and Fig. 3 is a plan view of a reed valve device for a two-stroke engine showing an embodiment of this invention. It is a diagram. 7... Body, 8... Valve port, 8a... Valve port proximal edge, 8b... Valve port side edge, 8c... Valve port tip edge, 9
...Valve seat, 10...Seat rib, 11...
...Reed valve.

Claims (1)

[Scope of utility model registration request] In a reed valve device in which a reed valve whose proximal end is fixed and whose distal end is a free end is brought into elastic contact with a valve seat on the outer peripheral surface of the valve port, the opening width of the reed valve free end side of the valve port is defined as the front and rear width. In addition to making it wider, a seat rib was formed that crossed the proximal edge and both side edges of the valve opening, excluding the opening edge on the free end side, and a single wide reed valve was installed in this wide valve opening. A reed valve device for a two-stroke engine characterized by the following.