JP2587771Y2 - Mounting structure of reed valve in 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 mounting structure used as an intake mechanism for a two-cycle engine.

[0002]

[Prior Art and Problems to be Solved by the Invention]
There are various types of intake mechanisms for a two-stroke engine, such as a piston valve type, a reed valve type, and a rotary valve type. It is often used as an intake mechanism in engines for hand-held work machines.

[0003] The reed valve is usually formed by fastening a thin plate-shaped reed valve and a reed stopper together with a screw member to an intake port opened in a valve seat member, and thus the intake of the crank chamber is performed. The reed valve attached to the mounting recess of the passage opens the suction port when the reed valve is drawn to the crank chamber side due to the pressure difference between the outside and the crank chamber caused by piston movement, and when the pressure difference decreases, the reed valve itself resilience The suction port is closed.

Therefore, in the reed valve system, when compared with a smooth piston valve system in which the change in the cross-sectional area of the suction port is small and the cross-sectional area of the reed valve system is large, the fuel which has not been atomized is reduced in the narrow gap of the mounting recess. It may stay in the part (gap part).

More specifically, in a small chain saw or the like, not only a sawing operation but also a branching operation are often performed. For such an operation, the equipment (engine) is, for example, erected as shown in FIG. When the operation is performed in the inverted posture from the posture, the fuel that has not been atomized stays in the gap portion A formed in the mounting concave portion. It has been pointed out that the fuel accumulated in the portion A flows into the crankcase, and as a result, the concentration of the mixed gas becomes high, causing idling malfunctions and engine stalls, thereby deteriorating the inclination performance.

On the other hand, since the mounting recess is also a space for accommodating the head of the screw member in which the reed valve and the reed stopper are fastened together to the valve seat member, a gap cannot be eliminated even if the dimensional accuracy is increased. There was also a problem.

[0007]

In this invention, a reed valve formed by fastening a thin plate-shaped reed valve and a reed stopper together with a screw member to an intake port of a valve seat member is provided in a mounting recess formed in an intake passage of a crank chamber. At the time of attachment, a flexible and non-oil-permeable elastic member is inserted into a gap formed between the mounting recess and the head of the screw member to keep the solid state, thereby preventing the fuel from remaining. The purpose of this is to improve the inclination performance of the engine by preventing the rotation.

In this case, it is preferable to provide a rib for locking the elastic member at a predetermined position of the mounting recess because it is possible to not only prevent the movement of the elastic member but also to facilitate the assembly.

[0009]

According to the reed valve mounting structure of the present invention, the gap formed between the mounting recess and the head of the screw member is tightly packed by a flexible and oil-impermeable elastic member. , No fuel stagnation occurs irrespective of the attitude of the equipment (engine).

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an embodiment of a reed valve mounting structure in a two-stroke engine according to the present invention.

That is, in the reed valve mounting structure of the present invention, the reed valve 10 itself has the suction port 14 at a predetermined position of the valve seat member 12 made of synthetic resin such as bakelite for heat insulation and damage prevention. At the same time, a thin plate-shaped reed valve 16 and a reed stopper 18 as a restricting member of the reed valve 16 are fastened to the suction port 14 together by a screw member 20. In addition, the reed valve 1 thus configured
Reference numeral 0 is attached to a mounting recess 26 provided at an end of an intake passage 24 communicating with the crank chamber 22 of the engine E by a screw member (not shown).

In the present invention, when the reed valve 10 is attached, the gap A formed between the mounting recess 26 and the head 20a of the screw member 20 is flexible and non-oil permeable. Elastic member 2 such as neoprene rubber
8 and the gap A
Is kept in a solid state.

According to the mounting structure in which the elastic member 28 is inserted, the elastic member 28 is densely inserted in the gap A formed between the mounting concave portion 26 and the screw head 20a. Irrespective of the posture of the machine (engine) in any posture, there is no danger that non-atomized fuel will stagnate. Therefore, the inclination performance is improved, so that there is no inconvenience such as idling malfunction or engine stall.

FIG. 2 shows the present invention in which a rib 30 is formed at a predetermined position of a mounting recess 26 provided at an end of an intake passage 24 communicating with a crank chamber 22 to lock an elastic member 28. 14 is another embodiment of the reed valve mounting structure according to the present invention. In this case, in addition to the same effect as the above-described embodiment, the movement of the elastic member 28 can be prevented by the rib 30.
Further, the elastic member 28 is attached to the inner surface of the mounting recess 26 and the rib 3.
Since the reed valve 10 can be assembled in a state where the reed valve 10 is locked in advance, the assembling can be facilitated.

[0015]

As described above, according to the reed valve mounting structure according to the present invention, the elastic member is inserted into the gap formed between the mounting concave portion and the head of the screw member, thereby achieving a solid state. , Fuel does not accumulate regardless of the posture of the device (engine) used. Therefore, since the inclination performance can be improved, the idling fuel does not become rich and the engine does not stop.

Further, it is simple in structure, has various advantages such as being able to suitably provide an engine for a hand-held work machine such as a small chain saw at a low cost, and its practical effect is extremely large.

Although the preferred embodiment of the reed valve mounting structure according to the present invention has been described above, the present invention is not limited to this embodiment. For example, the elastic member is not limited to rubber but is soft and elastic. Any material may be used as long as it does not allow gasoline to pass through, and various modifications can be made without departing from the spirit of the present invention.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view of an embodiment of a reed valve mounting structure according to the present invention.

FIG. 2 is a sectional view of another embodiment of the reed valve mounting structure according to the present invention.

FIG. 3 is a cross-sectional explanatory view of a conventional reed valve mounting structure, in which the posture of a device (engine) is changed from an upright state to an inverted state;
FIG. 4 is an explanatory view of a situation in which fuel accumulated in a gap portion A when returning to an upright state flows into a crank chamber.

[Explanation of symbols]

10 Reed valve, 12 Valve seat member, 1
4 suction port, 16 reed valve, 18 reed stopper, 20 screw member, 22 crank chamber,
24 intake passage, 26 mounting concave portion, 28 elastic member, A gap portion, E engine,

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F02B 25/20 F16K 15/16

Claims (2)

(57) [Scope of request for utility model registration] 1. A structure in which a reed valve formed by fastening a thin plate-shaped reed valve and a reed stopper together with a screw member to an intake port of a valve seat member is attached to a mounting recess formed in an intake passage of a crank chamber. A flexible and non-oil-permeable elastic member is inserted into a gap formed between the mounting recess and the head of the screw member, and the gap is tightly held by the elastic member. Mounting structure of a reed valve in a two-cycle engine. 2. The mounting structure for a reed valve in a two-stroke engine according to claim 1, wherein a rib for locking an elastic member is provided at a predetermined position of the mounting recess.