JPH0216355A - Rotating throttle valve type carburettor - Google Patents

Abstract

PURPOSE:To control the fuel flow rate precisely and improve the reproducibility by raising and lowering a regulating screw according to the rotation of a throttle body to push up and push down a needle for the increase and reduction of the fuel flow rate, and centering and holding the needle. CONSTITUTION:When a throttle body 15 is rotated clockwise, its throttle valve part 15C opens an inlet passage 11, so that the intake amount is increased. A controlling protruded part 15P is made in contact with a cam part 18B according to the clockwise rotation of the throttle body 15 to raise a holder 18, so that a regulating screw 19 is raised. A needle 17 is then raised by a spring 21, and thus the opening to the fuel well port 15B of the fuel control port 13B in a fuel nozzle 13 is increased to increase the fuel amount. In this case, the upper end part 17A of the needle 17 is centered and held by the taper end surface 19B of the regulating screw 19 inserted in the centering port 17B, whereby the movement of the needle 17 to the side is prevented.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a carburetor that controls the amount and concentration of air-fuel mixture supplied to an engine, and particularly relates to a so-called rotary throttle valve type carburetor in which a throttle valve rotates. It is related to vessels.

[Conventional technology]

The throttle valve of the carburetor is controlled by the driver's accelerator wire operation to adjust and control the amount and concentration of the mixture supplied to the engine, and there are generally two types: a rotating type and a sliding type. It is broadly divided into

The present invention relates to a rotary throttle valve type carburetor using a rotary throttle valve.
Publication No. 9 is known. According to this, the opening of the fuel control hole drilled in the fuel nozzle into the intake tract is controlled by a needle in response to the change in air amount due to the rotation of the throttle valve, and for this purpose the opening of the fuel control hole in the fuel nozzle is controlled by a needle. A needle is inserted into the throttle valve, and as the throttle valve opens, the needle is urged upward in the figure by a spring to increase the opening of the fuel control hole into the intake passage, thereby increasing the amount of fuel drawn into the intake passage. is increased in accordance with the increase in air volume.

The rear end of the needle is opposed to the tip of an A adjustment screw, and this adjustment screw adjusts the effective opening area between the needle and the fuel control hole drilled in the fuel nozzle. For example, by rotating the adjustment screw clockwise, the needle can be moved downward in the figure to reduce the effective opening area of the fuel control hole and thereby reduce the fuel amount. - By rotating the force adjustment screw counterclockwise, the needle is moved by the force of the spring, thereby increasing the effective opening area of the fuel control hole and increasing the amount of fuel.

If we pay attention to the shape of the end of the needle facing the adjusting screw, where the adjusting screw and the needle come into contact, it is formed into a planar shape.

[Problem to be solved by the invention]

This conventional rotary throttle valve type carburetor has the following problems.

The needle is inserted into the fuel control passage of the fuel nozzle, and moves synchronously with rotation of the throttle body to control the effective opening area of the fuel control hole of the fuel nozzle. . Here, it is desirable that the gap between the outer diameter of the needle and the inner diameter of the fuel control passage be zero from the point of view of fuel controllability, but there are cutting limits for the inner and outer diameters.
It was practically impossible to achieve zero from the point of concentricity. Therefore, since it is necessary for the needle to move freely and smoothly within the fuel control passage, a gap is provided between the inner diameter of the fuel control passage and the outer diameter of the needle.

Here, there is a gap between the inner diameter of the fuel control passage and the outer diameter of the needle, and the end of the needle opposite to the adjustment screw is formed in a flat shape. have a problem.

That is, the needle receives pulsating pressure generated in the intake passage through the fuel control hole of the fuel nozzle, and for this reason, the needle is located within the fuel control passage of the fuel nozzle, and the outer diameter of the needle and the fuel control passage are It moves laterally by the gap with the inner diameter (inner diameter of the fuel control passage - outer diameter of the needle). During this movement, if the needle is sucked toward the engine side and a gap is formed on the cleaner side, the amount of fuel sucked out from the fuel control hole decreases, while the needle is sucked toward the cleaner side and a gap is formed on the engine side. When this occurs, the amount of fuel sucked out from the fuel control hole increases, making it difficult to accurately control the fuel.

[Means to solve the problem]

The rotary throttle valve type carburetor of the present invention has been developed in view of the above-mentioned drawbacks, and an object thereof is to provide the above-mentioned carburetor with excellent fuel reproducibility when the throttle valve is repeatedly operated. To achieve this purpose, a throttle body that controls the amount of air flowing through the intake passage of the carburetor body; a needle that controls the effective opening area of a fuel control hole formed in the fuel nozzle; an adjustment screw that is arranged opposite to the needle and adjusts the effective opening area of the fuel control hole formed by the needle and the fuel control hole; This is a rotary throttle valve type carburetor in which the end of the needle that contacts the adjustment screw is centered and held at the tip of the 31 adjustment screw.

[Effect]

According to the rotary throttle valve type carburetor of the present invention, the air supplied to one engine is supplied through the gap formed by the throttle body, while the fuel is supplied through the fuel control hole formed in the fuel nozzle. It is controlled and supplied by a needle.

In particular, since one end of the needle is centered and held by the end of the adjustment screw, the amount of movement of the needle within the fuel control passage is smaller than that of conventional ones, so fuel control can be performed uniformly. be.

〔Example〕

Hereinafter, one embodiment of the rotary throttle valve type carburetor according to the present invention will be described with reference to FIGS. 1 and 2.

10 is a carburetor main body through which an intake passage I+ passes;
A cylindrical throttle valve guide tube 12 is bored in the middle of the intake passage 11 . The lower side of this throttle valve guide cylinder 12 crosses the intake passage 11 and enters the carburetor body 10 from the bottom of the intake passage 11, and the other side is opened from the upper side +OA of the carburetor body IO.

In addition, the upper part 10A of the carburetor main body lO of the throttle valve guide cylinder 12
The opening side has a diameter larger than that of the throttle valve guide cylinder 12 in order to accommodate a throttle valve return spring, which will be described later.

A fuel nozzle 13 is disposed protruding within the intake passage 11 at the bottom of the throttle valve guide cylinder 12, and a fuel control passage 13A is bored through the fuel nozzle 13 along its longitudinal axis. , the lower part of which is connected to the fuel flow path 14 via a fuel control jet J.

Further, the fuel control passage 13A is provided with a fuel control hole 13B, preferably a long groove along the longitudinal axis of the fuel control passage 13A.Therefore, the fuel flowing in the fuel flow passage 14 flows through the fuel control jet J and the fuel control passage. 13A.

The fuel flows out of the fuel nozzle 13 from the fuel control hole 13B.

In this embodiment, the fuel control hole 13B is opened toward the engine, but its opening position is determined as appropriate depending on the setting with the engine. Reference numeral 15 denotes a throttle body rotatably disposed in the throttle valve guide cylinder 12, and has the following configuration.

That is, 15A is a shaft portion which has a fuel well hole 15B surrounding the outer periphery of the fuel nozzle 13 with a gap S, and which opens at least into the intake passage 11. Plate-shaped throttle valve parts 15C and 15D that can control opening and closing of the passage 11 extend laterally. Furthermore, cylindrical bearing parts +5E and 15F that are fitted into the throttle valve guide cylinder 12 are provided at both upper and lower ends of the shaft part 15A that does not open into the intake passage 11, and further, the shaft part 15A that opens into the intake passage 11. is fuel well 15B (fuel nozzle 1
Through-hole 1 that communicates the outer circumferential gap S) of No. 3 with the intake passage 11
5G and +5H will be installed.

The number, diameter, and position of the through holes 15G and 15H are determined by the setting work with the engine.

Moreover, above the upper bearing part 15F and the carburetor main body 1
0 with a gap in the upper part 10A of the throttle valve lever part 15J.
is integrally provided, and this throttle valve lever part +5J
A cylindrical body 15K, for example, is integrally provided above. Four openings 15L are bored at the upper end of the cylinder 15, and the throttle body 1 is opened from the bottom of the opening recess 15L.
A holder fitting hole 15M and a needle fitting hole 15N are arranged in a row in the longitudinal axis direction of the fuel well 5 and substantially above the center thereof, and the needle fitting hole 15N located at the lower side penetrates into the fuel well 15B. .

Furthermore, a control projection 15F is provided on the side of the opening of the holder fitting hole 15M to the four openings 15L, that is, at the bottom of the opening recess 15L, which projects from the bottom. Also,
The cover 16 is arranged with gaps on the sides and above the cylinder 15 of the throttle body 15, specifically, the annular part 18A that surrounds the sides of the cylinder 15 and the upper part of the cylinder 15. The upper lid body 16B covers the throttle body 15, and a locking step IEIF protruding into the opening recess 15L of the throttle body 15 is provided at the lower part of the upper lid body 1BB.

A needle 17 is movably arranged in the needle fitting hole 15N of the throttle body 15, and the lower part of the needle 17 is connected to the fuel control passage 15N of the fuel nozzle 13.
The fuel well 15B of the fuel control hole 13B is inserted into the fuel well A.
This is to control the opening area for the needle 17.
The upper part of is disposed facing the holder insertion hole 15M side.

Also, a holder is placed in the holder fitting hole 15M of the Throntle body 15! A hole 18A is drilled from the top to the bottom inside the long axis of the boulder 18, and a cam part 18B is drilled from the side of the upper part of the holster 18. is provided, and this cam portion 18B
is in contact with the control protrusion 15F of the throttle body 15.

The cam portion 18B is provided radially from the center of the holder 18, and when the control protrusion 15F rotates about the center of the throttle body 15, the cam profile of the cam portion 18B causes the holder 18 to fit into the holder. Hole 1
It moves up and down within 5M.

Moreover, 18C is a locking protrusion provided to protrude from the holder 18, and this locking protrusion 18c is locked to a locking step 1θF of the upper lid IG. An adjusting screw 19 is screwed into the hole 18A of the holder 18, and the lower end of the adjusting screw 19 protrudes from the lower end of the holder 18 and comes into contact with the needle 17. Therefore, fuel nozzle +3. Needle +7. Throttle body 15. Holder 18. The longitudinal axis of the adjustment screw 19 is approximately concave.
placed in a straight line.

Further, reference numeral 20 denotes a holder spring, which is arranged approximately concentrically around the outer periphery of the adjustment screw 19. One end of the holder spring 20 is engaged with the cover 16, and the other end is engaged with the holder 18. Accordingly, the cam portion 18B of the holder 18 is connected to the control protrusion 15 of the throttle body 15.
At the same time, the locking protrusion 18G of the holder 18 is pressed against the locking step 18F of the cover 16.

Reference numeral 21 denotes a needle spring, which is contracted in the fuel control passage +3A of the fuel nozzle 13, one end of which is locked to the end of the needle 17 inserted into the fuel control passage +3A, and the other end of which is connected to the fuel control passage +3A. IF is applied to the control jet J. Therefore, the needle 17 is always urged upward by the spring force of the needle spring 21 and is held pressed against the lower end of the adjusting screw 19. ± is elastically pressed against the lower end of the adjustment screw 19.

Note that 22 is a throttle valve return spring, which is arranged approximately concentrically around the outer periphery of the bearing portion 15F of the throttle body 15, and one end of the throttle valve return spring 22 is locked to the slow two torque body 15. The other end is locked to a stave plate 23 that covers the upper part 10A of the carburetor main body 10, so that the throw two torque body 15 is always biased with a force in the closing direction.

In particular, the opposing ends of the adjusting screw 19 and needle 17 are made as follows. That is, the needle 17 is located at the end 17A of the needle 17 facing the adjustment screw 19.
The centering hole 17B on the long axis of the needle 1
7, while the adjustment screw 19
A tapered end surface 19B is formed at the end 19A facing the needle 17, the tapered surface of which contacts the opening of the centering hole 17B of the needle 17.

So, what are the needle 17 and the adjustment screw 19?

Centering hole 17B of needle 17 and tapered end surface 1
It is engaged at 98.

Next, its effect will be explained.

First, in order to increase the output of engine 5 from the idling state of the engine, the throttle body 15 is rotated clockwise in FIG.
The plate-shaped throttle valve portions 15C, +50 open the intake passage 11 and increase the amount of air flowing through the intake passage 11.

On the other hand, when the throttle body 15 is rotated clockwise, the control protrusion 15F comes into contact with the cam part 18B of the holder 18 and moves the holder 18 upward in the figure, and at this time the adjustment screw 19 also rotates. Holder 18
, the needle 17 moves upward by the spring force of the needle spring 21 by the amount of movement of the holder 18 and the adjustment screw 19, and the fuel control hole 13
By increasing the opening to the fuel well hole 15B of B, the amount of fuel can be increased in proportion to the increase in the amount of air.

Next, we will discuss the transition from high-speed operation to low-speed operation of the engine when the throttle body 15 is opened to a high opening.
The throttle body 15 rotates counterclockwise in the figure, and can close the intake passage 11 with throttle valve portions 15C and +50 to reduce the amount of air.

On the other hand, the holder 18 moves downward in the figure due to the contact between the cam part 18B and the control protrusion 15P, and the adjustment screw 18 moves the needle 17 against the spring force of the needle spring 21. By pressing in the molecular direction, the opening of the fuel control hole 13B to the fuel well 15B is reduced, thereby making it possible to reduce the amount of fuel commensurate with the reduction in the amount of air.

What should be noted here is that the lower part of the needle 17 is slidably supported by the inner diameter of the fuel control passage 13A of the fuel nozzle 13, and the adjustment screw 19 at the upper part of the needle 17
The centering hole 17B of the opposite end 17A is held centered by the tapered end surface 19B of the adjusting screw 19.

In this way, one end of the needle 17 is connected to the adjustment screw 19.
Since the needle 17 is centered and held at the end of the intake passage 11, when the needle 17 moves under pressure in the longitudinal direction of the intake passage 11 due to pulsating pressure generated in the intake passage 11 or vibration, the needle 17 The amount of movement of the intake passage 11 in the longitudinal direction can be made smaller compared to the conventional arrangement in which the fuel nozzle 13 is placed in a free state (relative to the longitudinal direction of the intake passage 11) within the fuel control passage 13A. It was made. Therefore, it is possible to provide the carburetor with excellent fuel reproducibility without fuel variations.

As shown in FIG. 3, the centering hole of the needle 17 may be a conical hole 30, and the end of the adjusting screw 19 may be a spherical end 31. Furthermore, as shown in FIG. may have a spherical end 31 , ie the end 1 ? of the needle 17 facing the adjusting screw 19 . It is sufficient that A is centered, and is not limited to this embodiment.

〔Effect of the invention〕

The rotary throttle valve type carburetor according to the present invention provides the following effects.

■Since the opposite end of the needle to the adjustment screw is centered and held at the end of the adjustment screw, movement of the needle in the fuel control passage of the fuel nozzle can be suppressed, and the inner diameter of the fuel control passage and the outer diameter of the needle can be Since the variation in the gap can be reduced, it is possible to provide the carburetor with accurate control of the fuel flow and high reproducibility, and a significant improvement in operating performance such as rotational fluctuations, especially during fitting operation of an engine that requires a minute flow rate. We were able to achieve this goal.

By centering the opposing part of the adjusting screw and needle, there is no sliding in the longitudinal direction of the intake path at the part facing the adjusting screw needle, so sliding wear in the opposing part can be completely suppressed. It has become possible to maintain stable performance over a long period of time, and in particular, it has 9 degrees of freedom in material selection, eliminating the need for treatment to increase surface hardness and reducing costs. be.

[Brief explanation of the drawing]

The figures show an embodiment of a rotary throttle valve type carburetor according to the present invention.
The cross-sectional view taken along line I, FIGS. 3 and 4 are longitudinal cross-sectional views showing other embodiments of the opposing ends of the needle and the adjusting screw. 10. Carburetor body +2. ,,, Throttle valve guide cylinder +3. ．． ．． ．． Fuel nozzle +3A, Fuel control passage 13B, Fuel control hole 15. , Throttle body 15A, Shaft portion 15F, Control protrusion 16
,,,,Cover 17. ,,, Needle +7A
,,opposite end 17B to adjusting screw 19,,centering hole +8. ,,,Holder 19. ,,Adjusting screw +9A, ,Opposite end 19B to needle 17, 2 taper end faces

Claims (2)

[Claims] (1) A throttle body that controls the amount of air flowing through the intake passage of the carburetor body; The throttle body is inserted into the fuel control passage of the fuel nozzle that can protrude into the intake passage, and the throttle body controls the flow of air into the fuel nozzle according to rotation of the throttle body. a needle for controlling the effective opening area of the fuel control hole to be drilled; an adjustment screw disposed opposite to the needle for adjusting the effective opening area of the fuel control hole formed by the needle and the fuel control hole; , a rotary throttle valve type carburetor in which the end of the needle that contacts the adjustment screw is centered and held at the tip of the adjustment screw. (2) A throttle body that controls the amount of air flowing through the intake passage of the carburetor body; The throttle body is inserted into the fuel control passage of the fuel nozzle that can protrude into the intake passage, and the throttle body controls the amount of air flowing through the intake passage of the carburetor body; a needle for controlling the effective opening area of the fuel control hole to be drilled; an adjustment screw disposed opposite to the needle for adjusting the effective opening area of the fuel control hole formed by the needle and the fuel control hole; A rotary throttle valve type carburetor in which either the rear end of the needle, where the needle and the adjusting screw face each other and come into contact with each other, or the tip of the adjusting screw have a tapered end surface shape.