JPS639664A - Sliding throttle valve type carburetor - Google Patents

Abstract

PURPOSE:To improve the intake efficiency and the fuel atomizing effect, by forming the sideface of a sliding throttle valve facing against an engine into an arch then arranging a jet needle to be fixed to the sliding throttle valve on a line connecting between the opposite ends of said sideface. CONSTITUTION:A throttle valve guide tube 3 is formed in a carburetor body 1 penetrated by an intake path 2, then a sliding throttle valve 6 is fitted slidably in said guide tube 3. The sideface 6A of said throttle valve 6 facing against an engine is formed into an arch. A jet needle 8 fixed to the sliding valve body 6 is arranged such that the center C thereof is positioned on a line connecting between the arched end sections A, B of said sideface 6A or nearer to the engine side than said line. The sideface 6B of the sliding throttle valve 6 facing against an air cleaner side is formed nearer to the air cleaner side than a line E-D passing through the center C of the jet needle 8 and crossing perpendicularly with the longitudinal axis X-X of the intake path 2 so as to connect between the arched end sections A, B.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a carburetor that adjusts and controls the amount and concentration of air-fuel mixture supplied to an engine, and in particular relates to a carburetor that adjusts and controls the amount and concentration of air-fuel mixture supplied to an engine, and particularly relates to a carburetor that has a throttle valve connected to an intake passage. This relates to a sliding throttle valve type carburetor that is movably disposed within a guide cylinder and is often used as a carburetor for motorcycle engines.

[Conventional technology]

Conventionally, as mentioned above, since sliding throttle valve type carburetors are often used in motorcycles, it is particularly important that the intake air supplied to the engine be efficiently produced. It is desirable that the groove remaining on the side of the intake passage of the throttle valve guide cylinder that guides and holds the valve is as small as possible, and there is a technique such as that disclosed in Japanese Utility Model Application Publication No. 47860/1985 filed by the present applicant. .

According to this, the sliding throttle valve consists of a flat valve part and a protrusion from the flat valve part toward the air cleaner side.
A jet needle is attached to this protrusion,
When the sliding throttle valve is fully open, only a thin rectangular groove corresponding to the flat valve part remains on the side of the intake tract.
Since the resistance of the groove to the airflow flowing through the intake passage can be minimized, the air intake efficiency can be improved.

[Problem that the invention seeks to solve]

However, while it was possible to improve the suction efficiency, since the jet needle is attached to a protrusion that is closer to the air cleaner than the flat valve part, it is possible to narrow down the intake passage to the maximum extent possible. It is separated from the flat valve part that can be used. According to this, air flows into the vicinity of the jet needle from around the protrusion, making it difficult to sufficiently increase the negative pressure applied to the jet needle and the needle jet into which the jet needle is inserted, which hinders atomization of the fuel. Therefore, it was impossible to expect an improvement in the fuel atomization characteristics when the sliding throttle valve was opened.

On the other hand, if a jet needle is placed in a flat valve part,
The jet needle is placed in the most constricted part of the intake tract, which improves the atomization characteristics of the fuel, but the thickness of the flat valve part tends to increase, which corresponds to the flat valve part. The grooves become large and create resistance to the airflow flowing through the intake tract, resulting in a decrease in intake efficiency.

[Child actor to solve problems]

The sliding throttle valve type carburetor of the present invention has been developed in view of the above problems, and has high suction efficiency, and also has good fuel atomization characteristics by increasing the negative pressure applied to the jet needle and needle jet. In order to achieve the above-mentioned purpose, the following steps have been taken.

That is, an engine in which the sliding throttle valve is constituted by a side surface facing the engine side and a side surface facing the air cleaner side, the side surface facing the engine side is arc-shaped, and includes a line connecting each arc-shaped end of the side surface facing the engine side. The center of the jet needle is located in the sliding throttle valve on the side, and the arcuate end is connected to the air cleaner side from a line passing through the center of the jet needle and perpendicular to the longitudinal axis of the intake passage. Opposite side surfaces are formed, and the sliding throttle valve is disposed within a throttle valve guide cylinder.

[Effect]

The jet needle is placed in the constricted part of the sliding throttle valve and does not allow air flow around the sides of the jet needle.

The negative pressure applied to the needle jet can be increased, and the groove that slides and guides the sliding throttle valve to the carburetor body can be maintained at approximately the same level compared to a flat throttle valve, which reduces suction efficiency. Never.

〔Example〕

Hereinafter, five embodiments of the sliding throttle valve type carburetor according to the present invention will be described with reference to FIGS. 1.2.3.

Reference numeral 1 denotes a carburetor main body through which an intake passage 2 passes through, and a throttle valve guide cylinder 3 is connected to the intake passage 2 and opens; A float chamber 5 is formed by this. A float 6 is disposed in the float chamber 5, and this float operates a valve seat disposed at the end of a fuel inflow path (not shown) and a float valve that opens and closes the valve seat, thereby keeping a constant amount of liquid in the float chamber 5. Form and hold the surface. Reference numeral 6 denotes a sliding throttle valve, which will be explained in more detail with reference to FIG. The sliding throttle valve 6 is formed by an engine side facing side surface 8A (right side in the figure) facing the engine side and an air cleaner side facing side surface 6B facing the air cleaner side.
A is formed in an arc shape (semicircular shape with a single radius R). Then, a needle 8 inserted into a needle jet (to be described later) on a line A-B connecting the arcuate ends A and B of the side surface 6A facing the engine side or on the engine side from the line A-B.
Place the center C of. More specifically, the center of the jet needle insertion hole BC into which the jet needle 8 is inserted and held may be placed on the line A-B or closer to the engine than the line 1A-B.

Then, it passes through the center C of the jet needle, and the intake path 2
On the air cleaner side (left side in the figure) from the line-E perpendicular to the longitudinal axis x-
An air cleaner side opposing side surface 6B connecting B is formed.

In the embodiment shown in FIG. 3, since a spring 7 is disposed to apply a force in the closing direction to the sliding throttle valve 6, the shape of the side surface 6B facing the air cleaner side is different from that on the air cleaner side (the left side in the figure). ) with a protrusion formed on it.

Further, an inclined surface 6D (cutaway) is formed at the bottom of the sliding throttle valve 6 toward the intake passage 2 to control the negative pressure applied to the needle jet 9 opening into the intake passage 2. This needle jet 9 is immersed below a constant liquid level in the float chamber 5 via a nozzle 10 and a main fuel jet 11.

The sliding throttle valve 6 can be movably arranged in the carburetor body in the following manner.

That is, the engine side guide cylinder surface 3 of the throttle valve guide guide cylinder 3
A (on the right side in the figure) is shaped like an arc so as to match the engine-side opposing side surface 6A of the sliding throttle valve 6, and its radius R is preferably the same as the radius R of the sliding throttle valve 6. Furthermore, this engine-side facing side surface 8A is formed by casting in the direction YY perpendicular to the intake passage 2. Further, the air cleaner side guide cylinder surface 3B of the throttle valve guide cylinder 3 is formed by casting so as to be inclined Z-Z with respect to the intake passage 2.

That is, the throttle valve guide cylinder 3 is shaped as described above, and the engine-side guide cylinder surface 3A that is perpendicular to the intake passage 2 is formed by casting out a die-cast core having such a shape in the inclined direction Z-Z without machining. The air cleaner side guide cylinder surface 3B that is inclined toward the intake passage 2 can be formed. (Note that it is impossible to cast both guide cylinder surfaces 3A and 3B in a direction perpendicular to the intake passage 2 due to the draft angle of the die-casting core.) 12 is the throttle valve. This guide block 12 is a guide block that is press-fitted into the guide cylinder 3, and this guide block 12 has an inclined surface 1 that matches the slope of the air cleaner side guide cylinder surface 3B of the throttle valve guide cylinder 3.
2A and the air cleaner side opposite side surface 6 of the sliding throttle valve 6
B, and a right-angled sliding surface 12B formed by casting in a direction perpendicular to the intake passage 2.

Therefore, the inclined surface 1 of the guide block 12 faces the air cleaner side guide cylinder surface 3B of the throttle valve guide guide cylinder 3.
The throttle valve guide tube T is formed by arranging and press-fitting the throttle valve guide tube T, and this throttle valve guide tube T is formed by casting in a direction perpendicular to the intake passage 2 on the engine side (right side in the figure). An engine-side guide cylinder surface 3A that matches the engine-side opposing side surface 6A of the sliding throttle valve 6 is formed, while an engine-side guide cylinder surface 3A is formed on the air cleaner side (left side in the figure) of the throttle valve guide cylinder T with respect to the intake passage 2. A right-angled sliding surface 12 formed in a right-angled direction and matching the air cleaner side opposing side surface 6B of the sliding throttle valve 6
B is formed.

Therefore, the sliding throttle valve 6 can be slidably disposed within the throttle valve guide tube T with a small gap.

Further, the sliding throttle valve 6 is guided to the carburetor main body 1 by the R end of the stratified throttle valve 6 being guided by the guide section G.

According to the N-moving throttle valve type carburetor having the above configuration, by operating the operating wire W, the sliding throttle valve 6 opens and closes the intake passage 2, thereby controlling the gap between the jet needle 8 and the needle jet 9, and In particular, according to the sliding throttle valve 6 according to the present invention, the side surface 6A facing the engine side of the sliding throttle valve 6 has an arc shape, so that it is not connected to the intake path on the engine side. When the sliding throttle valve 6 is sucked toward the engine side by the generated negative pressure, the distributed load of the pressing force of the engine-side facing side surface 8A of the sliding throttle valve 6 against the engine-side guide cylinder surface 3A is calculated using a conventional flat plate-shaped sliding plate. Since it is lower than a dynamic throttle valve, the durability and wear resistance of that part can be improved.

In addition, the jet needle 8 can be placed in the throttle part of the sliding throttle valve 6, and moreover, the inflow of air can be prevented from the surrounding area, especially from the upper and lower side parts in FIG. This makes it possible to increase the negative pressure generated in the needle jet 9.

Furthermore, since the guide portion G remaining in the intake passage 2 when the sliding throttle valve 6 is fully opened is made into a relatively small groove, a large amount of intake air can be taken in when the sliding throttle valve 6 is fully opened.

Further, as shown in FIG. 4, the side surface 6B facing the air cleaner side may be formed in an arcuate shape, or as shown in FIG. 5, the side surface 6B facing the air cleaner side may be linear. This is effective in shortening the overall length of the vessel.

〔Effect of the invention〕

As described above, the sliding throttle valve type carburetor of the present invention provides the following effects.

■Since the jet needle could be placed in the sliding throttle valve on the engine side, which includes a line connecting each arcuate end on the side facing the engine side, all the airflow to the jet needle and the needle jet is directed to the first child of the intake path. Since the flow is from the axial direction, the intake negative pressure for these can be increased compared to conventional ones, and this improves the atomization characteristics of the fuel, making it easier for the engine to open the sliding throttle valve. The response has been improved.

■The groove in the guide part of the sliding throttle valve to the carburetor body is approximately the same as the plate-shaped guide groove of the plate-shaped sliding throttle valve, and according to this, it improves the suction efficiency of the engine. It was possible to maintain the power well and improve the output.

■Since the side surface facing the engine side of the sliding throttle valve is arc-shaped, the area of the guide part to the carburetor body can be increased compared to the plate-shaped sliding throttle valve, and the suppressing load on the sliding part (unit: ) per unit area, we were able to provide a sliding throttle valve type carburetor with less wear on the sliding throttle valve over a long period of time and less leakage from the sliding throttle valve to the intake duct on the engine side. It is.

■The throttle valve guide cylinder that guides the sliding throttle valve is formed integrally with the carburetor body by casting, so it is generally processed afterward, but as mentioned above, the engine side guide cylinder surface is used to guide the throttle valve. When forming the cylinder by casting, the mold core is tilted and cast, and then a right-angled sliding surface is formed on one side of the guide block to match the opposite side surface on the air cleaner side of the sliding throttle valve, and the engine throttle valve guide is A guide block is press-fitted into the cylinder, and the sliding throttle valve is guided by a sliding surface perpendicular to the engine-side guide cylinder surface, so a throttle valve guide cylinder can be formed that is perpendicular to the intake passage. This eliminates the need for additional processing, reducing the manufacturing cost of the vaporizer.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the sliding throttle valve type carburetor according to the present invention, FIG. 2 is a top plan view of the state shown in FIG. 1 with the top cover removed, and FIG. 3 is the same as in FIG. 1. 4 and 5 are top plan views showing other embodiments of the sliding throttle valve. 608. Sliding throttle valve, 13A, side opposite to engine side,
6B, Air cleaner side opposite side, A, B,
,, each arcuate end of the side facing the engine side, C10, the center of the jet needle, E-D, , a line passing through the center of the jet needle and perpendicular to the longitudinal axis x-X of the intake passage, 12, ,, guide block, T10. Throttle valve guide tube. xy? g! 7 68 3 G Mayo B Go

Claims (2)

[Claims] (1) A sliding throttle in which a throttle valve guide cylinder is connected to the intake path that penetrates the carburetor body, and a sliding throttle valve with a jet needle arranged at the bottom is slidably arranged inside the throttle valve guide cylinder. In the valve type carburetor, the sliding throttle valve 6 is constituted by a side surface 6A facing the engine side and a side surface 6B facing the air cleaner side, the side surface facing the engine side is arc-shaped, and each arc-shaped end of the side surface facing the engine side The center C of the jet needle 8 is located within the sliding throttle valve 6 on the engine side, which includes the line A-B connecting A and B, and the longitudinal axis X of the intake passage 2 passes through the center C of the jet needle. - A sliding throttle valve type carburetor formed with an air cleaner side facing side surface 6B connecting arcuate ends A and B on the air cleaner side from a line ED perpendicular to -X. (2) Consisting of a side surface 6A facing the engine side and a side surface 6B facing the air cleaner side, the side surface facing the engine side is arc-shaped, and a line A connecting the arc-shaped ends A and B of the side surface facing the engine side
- The center C of the jet needle 8 is located in the sliding throttle valve 6 on the engine side including B, and a line E passing through the center C of the jet needle and perpendicular to the longitudinal axis XX of the intake passage 2 - An arcuate end A on the air cleaner side from D;
A sliding throttle valve type carburetor having a sliding throttle valve 6 formed with an opposite side surface 6B on the air cleaner side connecting B,
A throttle valve guide tube 3 is formed in series with the intake passage 2 passing through the carburetor body 1, and the engine side guide tube surface 3A of the throttle valve guide tube 3 is connected to the engine side opposite side surface 6A of the sliding throttle valve 6. The air cleaner side guide cylinder surface 3B of the throttle valve guide cylinder 3 is formed by casting in a direction perpendicular to the intake passage 2 so as to match the intake passage 2, while the Inside the valve guide guide tube 3, there is an inclined surface 12A that matches the air cleaner side guide tube surface 3B of the throttle valve guide guide tube 3, and a slope surface 12A that matches the air cleaner side opposing side surface 6B of the sliding throttle valve 6, A guide block 12 constituted by a right-angled sliding surface 12B formed in a direction perpendicular to A sliding throttle valve type carburetor is formed with a valve guide cylinder T, and a sliding throttle valve 6 is movably disposed within the throttle valve guide cylinder.