JPH10213028A - Intake pipe of 2 cycle engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a lowering of output without deforming tongue pieces, by improving the rigidity of left and right tongue pieces forming the smooth intake passage of an intake pipe. SOLUTION: This intake pipe 1 is formed by using an elastic body in a manner that an end inlet is formed into a cylindrical shape, and also a rear end flange part 3 is formed into a long square shape and connected to a reed valve body 4, and tongue pieces 9 which are brought in contact with the left and right inner side surfaces of the reed valve body 4, are projected on the left and right sides of the rear end flange part 3. In this case, projected pieces 10 projected to a rear side, are formed on the left and right sides of a core plate 8 inserted in the flange part 3, and inserted in the tongue pieces 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-stroke engine intake pipe.

[0002]

2. Description of the Related Art In a two-stroke engine, an intake pipe formed of an elastic material is connected to an end of an intake hole of the engine.
A carburetor is attached to the tip of the intake pipe to reduce the transmission of engine vibrations to the carburetor. Two-stroke engines open and close the intake air drawn into the crankcase by reciprocating pistons, and use a reed valve to open the reed valve and suck the intake air when the pressure in the crankcase is negative. There is.

[0003] In the case of using a reed valve, as shown in FIG. 7, the rear end of the intake pipe A has a rectangular cross section, and a flange B is provided at the rear end. It overlaps the lip D and is fastened to the end face of the intake hole of the engine. The reed valve body C has a rectangular cross section,
The upper and lower surfaces are tapered in a V-shape, and a reed valve F made of a spring plate is attached to one end of a window hole E on the upper and lower surfaces. E opens,
The intake air is sucked into the crank chamber. A stopper plate G is arranged outside the reed valve F to regulate the opening of the reed valve F.

As shown in FIG. 8, a core plate H is inserted into a flange B at the time of molding into an intake pipe A formed by using an elastic body, and the intake pipe A is connected to the reed valve body C by the flange B. At the same time, a gap is not formed when fastening to the end face of the intake hole of the engine. The inlet side of the intake pipe A connected to the carburetor is cylindrical, and the inner periphery of the reed valve body C is a rectangular shape. A tongue piece J whose inner surface gently changes from a circular cross section to a rectangular cross section is provided protrudingly along the inner surface of the side wall of the body C so that the flow of the intake air can be made smooth and the flow cannot be disturbed. For example, see Japanese Utility Model Publication No. 50-15052.

[0005]

The intake pipe A formed of an elastic material swells when it has been in contact with fuel gasoline or lubricating oil for a long time. The tongue piece J has no support because the outer side only touches the inner surface of the reed valve body C, and there is pressure fluctuation such as suction negative pressure. As shown by a two-dot chain line in FIG. Cause deformation. This deformation narrows the intake passage, reduces the amount of intake air, and lowers the output.

In view of the above, the present invention provides an intake pipe for a two-stroke engine that can increase the rigidity of left and right tongues forming a smooth intake passage of the intake pipe and prevent a decrease in output without deformation. The purpose is to:

[0007]

In order to achieve the above object, an intake pipe of a two-stroke engine according to the present invention has a cylindrical inlet end and a rectangular rear end flange, which is used for a reed valve body. An intake pipe that is connected to the rear end flange and protrudes tongues that contact the left and right inner surfaces of the reed valve body on the left and right sides, and is formed using an elastic body. That is, a projecting piece is formed, and the projecting piece is inserted into the tongue piece.

Since the left and right tongues of the intake pipe are respectively inserted into the left and right protrusions of the core plate, the rigidity of the tongues is greatly increased. This can prevent inward deformation during a long use period. Thus, the intake passage is narrowed, the intake air amount is reduced, and the output is not reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The intake pipe 1 is formed by using an elastic body, and the front end inlet is formed in a cylindrical shape so as to be connected to the vaporizer 2. The rear end is provided with a long rectangular flange 3, and the flange 3 is fitted with the flange 5 of the reed valve body 4 having a rectangular cross section, and is fitted with the end face of the intake hole 7 of the engine 6 using bolts. Fasten. The core plate 8 is inserted into the flange portion 3 so as to be deformed at the time of tightening so that no gap is formed. Tongue pieces 9 are protrudingly provided on the left and right sides on the rear side of the flange portion 3 so that the cross section changes smoothly from the cylindrical entrance to the reed valve body 4 having a rectangular cross section. The core plate 8 is provided with a protruding piece 10 protruding rearward on the left and right, and the protruding piece 10 is
To be inserted into Projection piece 10 of core plate 8
If the core plate 8 is die-cast using a light alloy, it can be integrally manufactured at low cost.

The left and right tongue pieces 9 gently change the inner surface of the intake pipe 1 from a circular shape to a rectangular shape of the reed valve body 4 to ensure a smooth flow of intake air. Since the left and right tongue pieces 9 have the protruding pieces 10 of the core plate 8 inserted inside, the rigidity is high, and the thickness of the elastic body of the tongue pieces 9 is
The amount of swelling caused by contact with gasoline or the like can be reduced by the amount of the insert of the protruding piece 10, and deformation can be prevented. For this reason, it is possible to prevent the intake passage from being narrowed, the intake air amount being reduced, and the output from being reduced.

[0011]

As described above, since the present invention is constructed as described above, the inner surface of the intake pipe is gently changed from a circular shape to a rectangular shape in cross section to secure a smooth flow of the intake air. Since the protruding pieces of the core plate are inserted into the tongue pieces, the thickness of the elastic body of the tongue pieces can be reduced, and swelling due to gasoline or the like can be reduced.
In addition, the rigidity of the tongue piece is increased by the protruding piece, so that the deformation of the tongue piece can be prevented, and a decrease in output due to narrowing of the intake passage can be prevented. Since the left and right protruding pieces can be formed integrally with the core plate, there is almost no influence on the manufacturing cost.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a front view showing the embodiment of the present invention.

FIG. 3 is a longitudinal sectional side view showing an embodiment of the present invention.

FIG. 4 is a plan view showing an embodiment of the present invention.

FIG. 5 is a rear view showing the embodiment of the present invention.

FIG. 6 is a side view of the entire engine showing the embodiment of the present invention.

FIG. 7 is an exploded perspective view showing a conventional example.

FIG. 8 is a longitudinal sectional plan view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Intake pipe 3 Flange part 4 Reed valve body 8 Core plate 9 Tongue piece 10 Protrusion piece

Claims (1)

[Claims] 1. A front end inlet having a cylindrical shape and a rear end flange portion having a rectangular shape are connected to a reed valve body, and a tongue piece which is in contact with left and right inner side surfaces of the reed valve body is provided on right and left of the rear end flange portion. In an intake pipe molded using an elastic body, a protrusion protruding rearward is formed on the left and right sides of the core plate to be inserted into the flange portion, and the protrusion is inserted into the tongue. A two-stroke engine intake pipe.