JPH01182526A - Lead valve - Google Patents

Abstract

PURPOSE:To prevent the permanent deformation of a lead plate in a lead valve having plural leads to open and close plural passages formed in a valve body by locating a branched part of each lead branching from its basic part on a side toward the tip of the lead from the edge of its part lappedly fixed with a lead stopper. CONSTITUTION:A lead valve 1 is formed of a valve body 2 having plural passages 3 and a lead plate 4 fixed to the body 2. The lead plate 4 is composed of a basic part 4a divided by slits 6 from its tip and lead part 4b, and fixed to the valve body 2 together with a lead stopper 5 by driving screws 8 into fixing holes 7 on the line A. Each lead 4b is tightly sat on a valve seat 3a of each passage 3. In this case, the lead stopper 5 is lapped on the basic part 4a of the lead plate 4 up to the line B, and fixed to the valve body 2, and then bent outward from the line B. A distance (a) between the line B and a branched part of the lead 4b is set to about 1-3mm, and a part of the lead 4b included within the above-mentioned distance (a) functions as a flexible part 4a1 to bend with the basic part 4a of the lead plate 4.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a reed valve used as an intake valve in a two-stroke engine.

(Prior art) An extremely thin plate of metal or synthetic resin is used for the lead of a reed valve in order to improve its flexibility, and in order to make good contact with the valve seat surface, a very thin plate of metal or synthetic resin is used for the lead of the valve body. The passage was divided into multiple sections and a lead was provided for each passage. As one of this type of reed valve, the device disclosed in Japanese Utility Model Application No. 61-77479 is known, and as shown in FIG.
A single lead plate a is divided by a slit leaving the base part to form branches c and c, and this lead plate a is superimposed with a lead stopper f on a valve body d having two passages e to form a screw g. The lead stopper f is located near the tip of the lead from the branching point, and is fixed by the screw g.
It overlaps with lead C from position A to line B, which is separated by a side.

Therefore, the lead C is bent by the airflow using the line B position as a fulcrum until it comes into contact with the lead stopper f to open the passage e, and when the airflow stops or goes in the opposite direction, it returns to its original position and closes the passage.

(Problem to be Solved by the Invention) When a valve with such a reed is used for a long period of time, fatigue occurs at the B line position where the maximum bending stress of lead C occurs.
It has been found that due to slight permanent deformation, the tip floats when the airflow stops, and when the pumping action is weak, the valve closing action becomes incomplete when starting up, leading to poor starting.

Therefore, the present invention aims to obtain a lead that does not undergo the above-mentioned permanent deformation while using a conventional thin lead plate that easily follows the airflow.

(Means for Solving the Problems) The present invention solves the above problems by changing the method of fixing the reeds. In a reed valve in which a reed plate with reeds branched from the base is overlapped and fixed to one side of the valve body together with a reed stopper, the branched part of the reed is connected to the reed free end side end (B) of the overlapped and fixed part with the reed stopper. It is characterized by being provided on the distal side of the tip.

(Function) By the above means, the reed is bent together with a part of the base of the reed plate when the valve is opened and closed, so that the amount of bending applied to the vicinity of the branching part of the reed is small, and the bending stress is also small. On the other hand, since the width of the chain portion of the flexible portion of the lead plate is larger than the sum of the widths of the leads, the bending stress is small. Therefore, the stress is relaxed near the fixed portion where the maximum bending stress occurs, and no permanent deformation occurs even after long-term use.

(Example) The present invention will be described in detail below based on the drawings. Figure 1 (
In a) and (b), 1 is a reed valve, 2 is the valve body, 3 is a ventilation passage, 3a is a valve seat surface, 4 is a reed plate, and 5 is a reed stop.

The lead plate 4 is divided by a slit 6.6 from the tip side to form a base 4a and a lead 4b, and a lead stopper 5.
It is fixed to the valve body 2 by a screw 9 passing through a fixing hole 7 along line A, and is in close contact with the valve seat surface 3a of each passage 3. A lead stopper 5 is fixed to the base 4a of the lead plate 4 so as to overlap up to the line B, and is bent outward from the line B. The distance a between the wavy line B and the branching part of the lead 4b is about 1 to 3 mm, and this part becomes the flexible part 4a1 and can bend together with the lead 4b.

This reed valve 1 is attached to, for example, a two-stroke engine 1o shown in FIG. In the engine 10, 11 is an intake pipe, 12 is a crankcase, 13 is a cylinder, 14 is a scavenging port, 15 is a piston, and 16 is a crankshaft. connected to the tip.

When a pumping action occurs due to the rotation of the crankshaft 16, each lead 4b is bent or restored by the air mixture flow to open and close the air passage 3 all at once. At this time, the lead plate 4, including the flexible portion 4a1, bends, so the bending amount near the branching portion of the lead 4b is small, and the bending stress is also small. And the flexible part 4
Although bending also occurs in a1, since the width of the chain portion 4a1 is larger than the sum of the widths of the respective leads 4b, the bending stress generated in the chain portion 4al is also small.

Therefore, the bending stress near the fixed part where the maximum bending stress occurs is reduced, and fatigue does not occur under small stress, so permanent deformation is unlikely to occur even after long-term use, and the tip of the lead 4b is placed on the valve seat surface. It is prevented from becoming separated from 3a.

(Effects of the Invention) As described above, the present invention prevents permanent deformation of the lead plate by only slightly changing the fixing state of the conventional lead plate.
It has the excellent effect of eliminating starting problems without increasing costs.

[Brief explanation of the drawing]

FIG. 1(a) is a front view of an embodiment of the present invention, FIG. 1(b) is a plan view of a lead plate, FIG. 2 is a longitudinal sectional view of an engine implementing the present invention, and FIG. 3(a) is a A front view of a conventional reed valve, and FIG. 3B is a plan view of a reed plate. 2... Valve body 4... Lead plate 4a...
Base part 4a1... Flexible part 4b... Li -
5... Lead stopper = 3 other people

Claims (1)

[Claims] In a reed valve in which a plurality of passages are provided in the valve body, and a reed plate in which a plurality of reeds for opening and closing each passage are branched from the base is superimposed and fixed to one side of the valve body together with a reed stopper, the branch part of the reed is fixed to one side of the valve body. A reed valve characterized in that the reed valve is provided on the distal end side of the reed free end side end (section B) of the overlapping fixed portion with the reed stopper.