JPS6311553B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a float valve device provided in a carburetor for supplying an air-fuel mixture to an internal combustion engine.

In Japanese Patent Application No. 58-44287 (Japanese Unexamined Patent Publication No. 59-170449), the inventor of the present application previously disclosed that a toggle mechanism controls the vertical movement of a float that moves up and down in response to changes in the fuel liquid level in the float chamber. and a lever mechanism connected in series to the toggle mechanism to transmit a signal to a valve member for opening and closing the fuel inlet to the float chamber. The toggle mechanism is
The buoyant force acting on the float is greatly expanded in a relatively small space, and the expansion rate is increased in a curved manner. The force magnified by this toggle mechanism is further amplified by the lever mechanism and transmitted to the valve member.

Therefore, according to the float valve device in which the toggle mechanism and the lever mechanism are connected in series, reliable opening and closing operations can be given to the valve member,
Since accidental leakage of fuel from the fuel inlet into the float chamber can be reliably prevented, it is possible to reliably prevent the fuel level in the float chamber from exceeding a specified level. This enables stable fuel supply.

An object of the present invention is to provide a float valve device that can reliably open and close a fuel inlet to a float chamber with a simpler configuration.

The present invention basically includes a float disposed in a float chamber of a carburetor, a valve member for opening and closing a fuel inlet for introducing fuel into the float chamber, and a valve member disposed above the float and disposed in the float chamber. a first arm member pivotally connected to a wall surface of the float chamber so as to slidably abut on an upper surface and swing in response to the vertical movement of the float; a second arm member having one end pivotally connected to the first arm member and the other end pivotally connected to the valve member between the contact portion and the abutting portion with the float; The arm member is characterized in that it acts as a lever mechanism that magnifies the buoyant force acting on the float, and also acts as a toggle mechanism in cooperation with the second arm member.

Further, the present invention provides the second arm member with an elastic deformation portion that can be elastically deformed in response to a compressive force acting in the longitudinal direction of the arm member, and further provides the second arm member with an elastic deformation portion that can be elastically deformed in response to a compressive force acting in the longitudinal direction of the arm member. The first
The fuel inlet can be opened and closed more reliably by providing a stopper for preventing the longitudinal axis of the arm member from aligning with the longitudinal axis of the second arm member. shall be.

The features of the present invention will become clearer from the following description of the illustrated embodiments.

The float valve device 10 according to the present invention has a first
As shown, a float chamber 16 defined by a housing 14 secured to the carburetor body 12, a float 18 disposed within the float chamber, a valve member 20, and first and second two arm members 22 and 24.

The housing 14 can be integrally formed with the carburetor body 12, and one side of the housing 14 includes:
A guide hole 26 extending laterally is formed to slidably receive the valve member 20 whose axis is disposed laterally. One end of the guide hole 26 opens into the float chamber 16 at the upper part thereof. A valve seat opening 28 is formed at the other end of the guide hole 24 , and the valve seat opening 28 communicates with a base 30 provided in the housing 14 . The mouthpiece 30 is connected to, for example, a conventionally well-known fuel pump (not shown), and the fuel pumped from the fuel pump is transferred so that the tip of the valve member 20 is connected to the valve seat opening 28.
When the valve member 2 is separated from the valve seat opening,
It is introduced into the float chamber 16 through the side of 0.

An air vent hole 32 similar to the conventional one is opened in the upper part of the float chamber 16. The fuel introduced into the float chamber 16 through the valve seat opening 28, which serves as a fuel inlet, flows through a well-known fuel guide path (not shown) extending from the bottom of the float chamber to the fuel nozzle of the carburetor. The fuel is then supplied to the internal combustion engine according to its operating conditions.

A valve member 20 for opening and closing the fuel inlet 28 in order to keep the fuel level in the float chamber 16 substantially constant is connected to the float 18 via the first and second arm members 22 and 24.
linked to.

First and second arm members 22 and 24
is disposed within the float chamber 16 above the float and substantially along the axis of the valve member 20. One end of the first arm member 22 has a first pivot 34 extending laterally perpendicular to the axis of the valve member 20 on the opposite side of the valve member 20.
It is pivotally connected to the housing 14, which is the wall of the float chamber, through. This first arm member 2
The other end of the float 18 slidably abuts on the upper surface of the float 18 at its center. Therefore, the first arm member 22 moves in the vertical direction around the pivot shaft 34 as a fulcrum in conjunction with the vertical movement of the float 18, which moves up and down in response to changes in the fuel level H in the float chamber 16. It is possible to swing to

One end of the second arm member 24 is connected to the first pivot 3
The first arm member 22 is pivotally connected to the first arm member 22 between its ends via a second pivot shaft 36 parallel to the second arm member 4 . Further, the other end of the second arm member 24 is
It is pivotally connected to the base of the valve member 20 via a third pivot 38 parallel to the first pivot. First,
A line connecting the centers of the second and third pivots 34, 36 and 38 forms a triangle, and the second pivot 36 is greater than the line h connecting the centers of the first and second pivots 36 and 38. It is located on the side of the float 18. Therefore, as the first arm member 22 swings, the valve member 20 connected to the first arm member via the second arm member 24 opens the valve seat opening 28 which is the fuel inlet. The valve member is slid along the guide hole 26 to open and close, and thereby the valve member operates to open and close the fuel inlet 28 in conjunction with the vertical movement of the float 18.

Regarding the vertical movement of the float 18 described above, the buoyant force shown by the symbol F acting on the float acts on the other end of the first arm member 22 that comes into contact with the float. This buoyant force F is determined by the lever ratio of the first arm member, that is, the distance L 1 from the fulcrum of the first arm 22 to the point of application of the buoyant force, and the distance L ₁ from the fulcrum of the first arm 22 to the second arm member. It is enlarged by the ratio of the distance L ₂ to the second pivot 36, which is the pivot point of the second pivot 36, and acts on the second pivot 36 upward in the figure. Furthermore, a constant value of the lever ratio (L ₁ /
The buoyant force (F×L ₁ /L ₂ ) magnified by L ₂ ) is the first
The force is magnified by the toggle ratio (T) via the toggle mechanism constituted by the second arm members 22 and 24. As a result, when the valve member 20 is in the closed position of the fuel inlet 28, it is pressed against the fuel inlet with a strong force (F×L ₁ /L ₂ ×T). The force magnification rate (T) due to this toggle mechanism does not exhibit a linear characteristic like the lever ratio, but rather
As the angle θ between the line h connecting the centers of 4 and 38 and the axis of the first arm member decreases, it increases quadratically.

Therefore, according to the float valve device 10, the valve member can be reliably operated to maintain the fuel level H in the float chamber constant, and the fuel level H can be maintained as shown in FIG. When at a specified value as shown, said valve member 20
can be pressed against the fuel inlet 28 with strong force to reliably close the fuel inlet.
The fuel level H in the float chamber can be reliably prevented from exceeding a specified value, and the fuel level can be maintained at an appropriate level.

2 to 5 show other embodiments of the invention, in which components having the same function as shown in FIG. 1 are given the same reference numerals.

In the float valve apparatus 10 shown in FIGS. 2-5, as best seen in FIG. It consists of a flat plate member pivotally connected to. The first arm member 22 has a pair of mutually parallel extensions on the side opposite to the one end which is the pivot point to the housing 14, and abuts the float 18 at the extensions.

The second arm member 24 is made of a linear member. One end of the second arm member 24 is pivotally connected to the first arm member 22 between the pair of extensions via a first pivot shaft 36 integrally formed on the arm member. Further, the other end of the second arm member 24 is pivotally connected to the valve member 20 via a third pivot shaft 38 formed integrally with the arm member.
As clearly shown in FIG. 2, a U-shaped deformed portion 40 is formed in the intermediate portion of the second arm member, and the deformed portion extends from both ends of the second arm member. When a compressive force is applied in the axial direction of the arm between them, elastic deformation occurs. Further, a stopper 42 that can come into contact with the second arm member 24 is provided on the upper wall surface of the float chamber 16 .

In the example shown in FIGS. 2 to 5, when the fuel level H in the float chamber 16 is at the specified level as shown in FIG. As explained for the example shown in , _{the applied force (F×L 1 / L 2} ×
T), the valve member 20 is pressed against the valve seat opening 28 which is the fuel inlet, but the valve member 20 is elastically pressed by the spring action of the deformable portion 40. Further, when the float 18 moves excessively upward due to engine vibration or the like, the stopper 42 comes into contact with the second arm 24 as shown in FIG. member and second
preventing the respective longitudinal axes of the arm members from being aligned.

That is, in order for the first and second arm members 22 and 24 to act as a toggle mechanism,
As mentioned above, the first, second and third pivots 3
The line connecting the centers of the first and second pivots 34 and 38 forms a triangle, and the second pivot 36 must be located closer to the float 18 than the line h connecting the centers of the first and second pivots 34 and 38. However, if the second arm member 24 is provided with the deformable portion 40, the excessive movement of the float 18 will cause
The second arm member 24 may be temporarily highly compressed, which may reverse the position of the second pivot 36. When the position of the second pivot 36 is reversed and the pivot moves above a line connecting the first and third pivots, the rise of the float causes the valve member 20 to move toward the valve seat opening. The float valve device therefore loses its function.

However, the stopper 42 prevents the longitudinal axes of the first and second arm members from being aligned, thereby preventing the second pivot 3 from being aligned.
6 is prevented from being reversed, the valve member is reliably operated to open and close the fuel inlet due to the buoyant force received by the float 18, and the valve member 20 in the closed position is protected against engine vibrations and the like. Therefore, the fuel inlet 28 is not separated from the fuel inlet 28 and the valve seat is not worn out.
will be closed more securely.

Although an example has been described in which the stopper 42 is arranged so as to be able to come into contact with the second arm member 24, the stopper 42 may be placed in contact with the first arm member 24 as necessary.
2 or the float 18 or the like so as to be able to come into contact with it.

According to the present invention, as described above, the first arm member acts as a lever mechanism that magnifies the buoyancy force acting on the float, and also acts as a toggle mechanism in cooperation with the second arm member. Therefore, it is possible to reliably open and close the fuel inlet with a relatively simple configuration without independently providing a toggle mechanism and a lever mechanism, thereby preventing accidental leakage of fuel from the fuel inlet into the float chamber. Since leakage can be reliably prevented, the fuel level in the float chamber can be reliably prevented from exceeding a specified level, thereby making it possible to stably supply fuel to the internal combustion engine.

Further, according to the present invention, since the second arm member is provided with an elastically deformable portion that acts as a buffer, the opening and closing of the fuel inlet can be further facilitated without incorporating an independent buffer member such as a coil spring. It can definitely be done.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a float valve device according to the present invention, FIG. 2 is a diagram similar to FIG. 1 showing another embodiment of the present invention, and FIG. 3 is a diagram similar to FIG. is a cross-sectional view taken along the line -,
FIG. 4 is a longitudinal sectional view similar to FIG. 2, showing the float shown in FIG. 2 in a state of excessive motion. 14: Housing (wall surface), 16: Float chamber,
18: float, 20: valve member, 22: first arm member, 24: second arm member, 28: fuel inlet (valve seat opening), 34, 36, 38: pivot,
40: Elastic deformation part, 42: Stopper.

Claims (1)

[Scope of Claims] 1. A float disposed in a float chamber of a carburetor, a valve member for opening and closing a fuel inlet for introducing fuel into the float chamber, and an upper surface of the float located above the float. a first arm member pivotally connected to a wall surface of the float chamber so as to slidably abut on the float and swing in response to the vertical movement of the float; and a pivoting portion of the first arm member to the wall surface; and a second arm member having one end pivotally connected to the first arm member and the other end pivotally connecting to the valve member between the contact portions with the float. Valve device. 2. The first arm member is pivotally connected to the wall surface via a pivot, and the second arm member is coupled to the first arm member and the valve via a pivot having axes parallel to the axis of the pivot. A float valve arrangement according to claim 1, wherein the float valve arrangement is pivotally connected to each of the members. 3. A float disposed in a float chamber of a carburetor, a valve member for opening and closing a fuel inlet for introducing fuel into the float chamber, and a valve member located above the float and slidably abutting on the upper surface of the float. and a first arm member pivotally attached to the wall surface of the float chamber to swing in accordance with the vertical movement of the float, and a pivoting portion of the first arm member to the wall surface and the float. A second arm member having one end pivotally connected to the first arm member and the other end pivotally connected to the valve member between the connecting parts, and the second arm member is elastically deformed in response to a compressive force acting in the longitudinal direction. a second arm member provided with an elastic deformation that is capable of deflecting the longitudinal axis of the first arm member and the longitudinal axis of the second arm member by excessive upward movement of the float; and a stopper for preventing the float valves from aligning. 4. The float valve device according to claim 3, wherein the stopper is provided on the upper wall surface of the float chamber so as to be able to come into contact with the second arm member. 5. The float valve device according to claim 4, wherein the elastic deformation portion is a U-shaped bent portion.