JPS6347954B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reed valve used in two-stroke engines and the like.

Some two-stroke engines with preloaded crank chambers have a reed valve disposed between the carburetor and the crank chamber to prevent fresh air in the crank chamber from flowing back into the carburetor. As one of these reed valves,
There is a generally flower-shaped type in which reeds having radially formed reed pieces and stoppers having radially formed stopper pieces are fixed concentrically to a substrate having a plurality of annularly arranged valve holes. With such a reed valve,
In particular, since each reed piece and each stopper piece are connected in sequence, if foreign matter such as dust gets caught between the reed piece and the stopper piece, it is difficult for this foreign matter to fall out. On the other hand, since this foreign material causes stress to be concentrated on the lead piece, there is an inconvenience that unless the foreign material falls off, the durability of the lead will decrease.

The present invention was made in view of these inconveniences, and provides a generally flower-shaped reed valve in which reeds and stoppers are formed in a radial manner, by making it easier to remove foreign matter that gets stuck between the reed pieces and the stopper pieces, and improving the durability of the reeds. The purpose is to provide a reed valve that can improve the

According to the present invention, the object is to provide a substrate having a plurality of annularly arranged valve holes, a reed having a plurality of radially formed reed pieces facing each of the valve holes, and a deflection amount of each of the reed pieces. In the reed valve equipped with a stopper having stopper pieces formed radially to regulate This is achieved by a reed valve, which faces into an opening of the reed valve, and is configured to discharge foreign matter stuck between the stopper piece and the reed piece from the opening. The present invention will be described in detail below based on embodiments shown in the drawings.

FIG. 1 is a partially sectional plan view of a crankcase preload type two-stroke engine for an outboard motor as an embodiment of the present invention, FIG. 4 is a plan view of the stopper.

In FIG. 1, numeral 10 is a cylinder block;
12 is a cylinder head, 14 is a piston, 16 is a vertically disposed crankshaft, 18 is a connecting rod, and 20 is a crankcase. This engine has two cylinders with a phase difference of 180 degrees, and as is clear from Figures 1 and 2, air-fuel mixture is taken into the crank chambers 22 and 24 of each cylinder from a single carburetor 26. . That is, the crankcase 20 has a board 2.
A connecting member 30 is connected via 8, and this connecting member 3
0 is further connected to a carburetor 26, and the air-fuel mixture is delivered to the crank chambers 22, 24 of the upper and lower cylinders, respectively, through two reed valves 32, 34 provided on the base plate 28.
inhaled alternately. In addition, 36 in Figure 2
3 is a throttle valve provided in the carburetor 26, and 38 is also a choke valve.

Next, the reed valves 32 and 34 will be explained, but since they have completely similar configurations, the reed valve 32 and 34 will be explained below.
4 will be mainly described, and the same parts of the reed valve 32 will be given the same reference numerals so that the description thereof will not be repeated. 40 is each reed valve 3
Eight valve holes are formed in the substrate 28 for each valve hole 2 and 34, and these valve holes 40 are arranged in an annular shape. The valve hole 40 of the reed valve 32 is connected to the space 42 in the connecting member 30 and the crank chamber 2 of the above-mentioned cylinder.
2, and the valve hole 40 of the reed valve 34 communicates the space 42 with the crank chamber 24 of the lower cylinder. A valve seat 44 made of oil-resistant rubber is baked into the opening edge of each valve hole 40 on the crankcase side (see FIG. 2). Improves durability. A lead 46 is formed into a radial flower shape by eight lead pieces 48. These reed pieces 48 cover the eight valve holes 40 arranged annularly. Reference numeral 50 denotes a stopper, which is formed into a radial substantially flower shape by eight stopper pieces 52. Each stopper piece 52 of this stopper 50
As shown in FIG. 3, the notches 54 located therebetween are shallower than the notches 56 located between each lead piece 48 of the lead 46. Four openings 62 are formed in the central portion of the stopper 50 where the respective stopper pieces 52 are connected to each other, that is, in the gathering portion 60 of the base portions 58 of the respective stopper pieces 52. these 4
The openings 62 are formed in an arc shape as shown in FIGS. 3 and 4, and each opening 62 is located so as to straddle the base 58 of the adjacent stopper piece 52. That is, for example, in FIG. 4, the opening 62A located at the base 58A of one stopper piece 52A extends to the bases 58B, 58B of the stopper pieces 52B, 52B adjacent on both sides, and this opening 62A has three
It is designed to straddle the three base portions 58B, 58A, and 58B. As is clear from FIG. 3, the notch 54 of the lead 46 faces into the opening 62.
The depth of these cuts 56 and the radial position of the openings 62 are determined. The lead 46 and the stopper 50 are inserted into the eight annular valve holes 4 formed in the base plate 28 by bolts 64 passing through their centers.
It is fixed at the center of 0. The reed pieces 48 face each valve hole 40, and each stopper piece 52 is curved so that its tip is gradually separated from each reed piece 48, thereby regulating the amount of deflection of the reed piece 48.

Next, the operation of this embodiment will be explained. When the crankshaft 16 rotates, the crank chambers 2 of each upper and lower cylinder
Negative pressure is generated alternately at ports 2 and 24 with a phase difference of 180°. The air-fuel mixture generated in the carburetor 26 passes from the space 42 in the connecting member 30 through the valve holes 40 that communicate with the crank chambers 22 and 24 of the cylinders where negative pressure has been generated, and then pushes open the reed pieces 48 to open each of the cylinders. It flows into the crank chambers 22 and 24. The lead piece 48 is pushed open and comes into contact with the curved surface of the stopper piece 52, and the lead piece 4
The amount of deflection of 8 is regulated. If a foreign object gets stuck between the lead piece 48 and the stopper piece 52,
As the reed piece 48 vibrates, this foreign material penetrates deeply into the space between the reed piece 48 and the stopper piece 52. However, since an opening 62 is formed in the gathering part 60 of the base 58 of each stopper piece 52, this foreign material falls out from this opening 62. Therefore, the amount of foreign matter that accumulates between the stopper piece 52 and the lead piece 48 is reduced, and stress concentration on the lead piece 48 is reduced.

In this embodiment, in order to form the opening 62, the notch 54 of the stopper 50 is made shallower, and the collecting portion 60 is made wider. Conventional stopper leads 5
Compared to the case where the notches 56 have the same depth as the notches 56, when the notches 54 are made shallower as in this embodiment, it becomes more difficult for the air-fuel mixture to flow near these notches. However, in this example, lead 4
Since the notch 56 of No. 6 extends to the opening 62 of the stopper 50, the air-fuel mixture flows out from this opening 62. Therefore, the flow of the air-fuel mixture is not hindered much, and the flow path resistance hardly increases.

FIG. 5 is a plan view of another stopper 70 that can be used in place of the stopper 50 in the embodiment described above. This stopper 70 includes a stopper piece 72 similar to the stopper 50 shown in FIG. . With this stopper 70, the opening 78 becomes wider, so
It becomes possible to more effectively discharge foreign matter stuck between the lead and the stopper piece.

As described above, in the present invention, the radial stoppers that regulate the amount of deflection of the radial lead pieces have a plurality of openings formed at the gathering part of the base of each stopper piece, so that there is a gap between the lead pieces and the stopper pieces. The vibration of the embedded reed piece causes it to penetrate deeply into the base of the stopper piece, and is then discharged to the outside through the opening. Therefore, even if stress concentration occurs on the lead piece due to foreign matter, this stress concentration is released by expelling the foreign matter from the opening, and the durability of the lead is improved. In addition, since the notches between each reed piece of the reed face the opening provided in the stopper, part of the gas such as the mixture that has passed through the valve hole can flow from the notch in the reed through the opening in the stopper. This allows for smooth gas flow.

[Brief explanation of the drawing]

Fig. 1 is a partially sectional plan view of an embodiment of the present invention, Fig. 2 is a - line sectional view thereof, Fig. 3 is a - line sectional view in Fig. 2, and Fig. 4 is a plan view of the stopper. be. FIG. 5 is a plan view of another stopper. 28... Board, 32, 34... Reed valve, 40
... Valve hole, 46 ... Lead, 48 ... Lead piece,
50,70...Stopper, 52,72...Stopper piece, 56...Notch, 58,74...Base, 6
0,76...Collection part, 62,78...Opening.

Claims (1)

[Claims] 1. A substrate having a plurality of annularly arranged valve holes, a reed having a plurality of radially formed reed pieces facing each of the valve holes, and a radial stopper piece for regulating the amount of deflection of each of the reed pieces. In the reed valve equipped with a stopper formed therein, a plurality of openings are formed in a gathering part of the base of each front-filling stopper piece, and a notch between each reed piece of the reed faces into the opening of the stopper, A reed valve characterized in that foreign matter trapped between the stopper piece and the reed piece is discharged from the opening.