JPH01142255A - Rotary throttle valve type carburetor - Google Patents

Abstract

PURPOSE:To improve the atomizing characteristic and suction efficiency of fuel by coaxially providing a fuel injection nozzle and a throttle body, etc. inside a throttle valve guide cylinder which is perpendicularly provided to the suction passage of a carburetor body. CONSTITUTION:A suction passage 11 passes through the inside of a carburetor body 10 while a throttle valve guide cylinder 12 is perpendicularly provided to the suction passage 11. A fuel nozzle 13 is erected from the bottom portion of the throttle valve guide cylinder 12 to the inside of the suction passage 1 while forming a throttle body 15 with the outer periphery of the fuel nozzle 13 inside the throttle valve guide cylinder 12. A holder 18 and a needle 17 are provided in the fitting bores 15M, 15N of the throttle body 15 respectively while one end portion of the needle 17 is inserted into the fuel control passage 13A of the fuel nozzle 13. Further a cover 16 is provided on the opening end portion of a throttle valve guide cylinder 12. Further, a over 16 is provided on the opening end portion of the throttle guide cylinder 12. On the other hand, an adjusting screw 19 one end of which is opposite to the needle 17 is screwed to the holder 18.

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 operator's accelerator wire operation to adjust and control the amount and concentration of the mixture supplied to the engine. It is broadly divided into.

The present invention relates to a rotary throttle valve type carburetor using a rotary throttle valve, and as a prior art, a structure as shown in Japanese Utility Model Publication No. 1989-19969 shown in FIG. 1 is known. According to this, a valve inner cylinder 3 is perforated perpendicularly to an intake passage 2 passing through the carburetor main body l, and a cylindrical cylinder with a through hole 4 corresponding to the intake passage 2 is bored inside the valve inner cylinder. A rotary valve 5 is rotatably arranged, and a control valve rod 7 connects a fuel control hole (not shown) of a fuel nozzle 6 which is arranged to protrude into the intake passage in accordance with the rotation of the rotary valve. It is controlled.

[Problem that the invention seeks to solve]

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

1. As shown in FIG. 1, the air sucked into the engine is supplied to the rotary throttle valve 5 through a throttle section 5A on the air cleaner side (left side in the figure), a throttle section 5B on the engine side (right side in the figure), and a through hole 4. The air flows through the inner chamber 5C formed by the intake passage 2. According to this, air flows diagonally upward from the bottom in the figure in the inner chamber 5C of the rotary throttle valve 5, and flows into the intake path 2 (engine-side intake path).

Therefore, the fuel sucked into the inner chamber 5C from the fuel nozzle 3 flows in a diagonal direction with respect to the longitudinal axis of the intake passage 2, so that it tends to adhere to the wall surface of the inner chamber 5C of the rotary throttle valve 5, resulting in fuel mist. This is unfavorable in terms of combustion in the engine.

Further, the air flow is also throttled by the air cleaner side throttle part 5A of the rotary throttle valve 5, then flows into the inner chamber 5C of the rotary throttle valve 5, and is further throttled by the engine side throttle part 5B. At least up to the intermediate opening range of the rotary throttle valve 5
Since the throttle part 5B on the engine side is in a state of blocking the extension of the opening of the throttle part 5A on the air cleaner side of the rotary throttle valve 5, it is difficult to improve the efficiency of air intake into the engine. You can't expect good output.

2. The negative pressure generated in the intake passage 2 on the engine side from the rotary throttle valve 5 is transferred to the intake passage 2 from the gap A between the intake passage 2 and the throttle part 5B on the engine side of the rotary throttle valve 5. However, when the opening degree (gap A) of the throttle portion 5B is small, especially when the engine is operating at low speed, the volume of the interior chamber 5C of the rotary throttle valve 5 is smaller than that of the rotary throttle valve. Since the volume is large compared to the opening degree of No. 5, the pressure decreases inside the room 5C and the negative pressure of the intake passage applied to the fuel nozzle 6 cannot be maintained in a large state. According to this, the fuel suction characteristics are improved. In addition, it is not possible to improve the atomization characteristics of the sucked fuel, which is unfavorable in terms of engine operability.

[Means for solving problems]

The rotary throttle valve type carburetor of the present invention has been developed in view of the above-mentioned disadvantages, and aims to provide the above-mentioned carburetor with good fuel atomization characteristics and excellent suction efficiency. For this purpose, there is a carburetor main body in which an intake passage passes through the interior, and a cylindrical valve inner cylinder is perforated substantially perpendicular to the intake passage and across the intake passage; established.

A fuel nozzle in which one end of a fuel control passage penetrating through the interior is connected to a fuel flow path and a fuel control hole opened from the fuel control passage into the intake passage; and a fuel well having a gap around the outer periphery of the fuel nozzle. a shaft portion surrounded by a hole and opening at least into the intake tract; a plate-shaped throttle valve portion extending laterally from the shaft portion and capable of controlling opening/closing of the intake tract;
A through hole is formed in the shaft part and connects the gap between the fuel nozzle and the intake passage, a bearing part is located at both the upper and lower ends of the shaft part and is rotatably fitted into the inner cylinder of the valve part; In addition, a throttle valve lever part protrudes from the carburetor body, and a holder fitting hole and a needle fitting hole are connected and bored on the lower side of the bearing part from the upper opening of the cylindrical body connected above the throttle valve lever part. and a control protrusion that protrudes laterally from the opening of the holder fitting hole; a throttle body that is movably disposed within the holder fitting hole of the throttle body and corresponds to the control protrusion of the throttle body. A holder having a cam portion and a locking protrusion; A needle movably disposed in a needle insertion hole of a throttle body and having one end thereof inserted into a fuel control passage of a fuel nozzle; A valve of a carburetor body; An upper lid body is placed on the open end of the internal cylinder and covers the vicinity of the upper part of the cylinder body of the throw and torque body. A rotary throttle valve type carburetor is constructed by: a cover having a locking stepped portion for inhibiting rotation; and an adjustment screw screwed onto the holder and having one end facing the needle.

[Effect]

According to the rotary throttle valve type carburetor of the present invention, air is supplied to the engine through a gap formed by the plate-shaped throttle valve portion of the throttle body and the intake passage, and through a gap formed in the shaft portion of the throttle body. On the other hand, fuel is controlled by a control valve rod from a fuel control hole formed in a fuel nozzle and is supplied through a through hole in a throttle body. According to this, the fuel sucked out from the fuel control hole can be mixed well with air and supplied to the engine.

〔Example〕

An embodiment of the rotary throttle valve type carburetor according to the present invention will be described below.
This will be explained with reference to Fig. M42, Fig. 3, and Fig. 4.

10 is a carburetor main body through which an intake passage 11 passes;
A cylindrical valve inner cylinder 12 is bored in the middle of the intake passage 11 . The lower side of this valve inner 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 10A of the carburetor body 10.

The opening side of the valve inner cylinder 12 at 1°A above the carburetor main body 10 has a diameter larger than that of the valve inner cylinder 12 in order to accommodate a throttle valve return spring, which will be described later. A fuel nozzle 13 is disposed upwardly in the intake passage 11 at the bottom of the valve inner cylinder 12, and a fuel control passage 13A is bored through the fuel nozzle 13 along its longitudinal axis. , its lower part is connected to the fuel flow path 14.

Further, a fuel control passage 13B is bored in the fuel control passage 13A, and a long groove extending along the longitudinal axis of the fuel control passage 13A is preferable.

Therefore, the fuel flowing in the fuel flow path 14 is transferred to the fuel control path 13.
A, 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 appropriately set by motoring with the engine. ! Reference numeral 5 denotes a throttle body rotatably disposed in the valve inner cylinder 12, and has the following configuration.

That is, 15A is a shaft portion that has a fuel well hole 15B surrounding the outer periphery of the fuel nozzle 13 with a gap S, and that 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.

Further, the upper and lower ends of the shaft portion 15A that do not open into the intake passage 11 are provided with cylindrical bearing portions 15E that are fitted into the valve inner cylinder 12.
.
, 15H is drilled.

The number, diameter, and position of the through holes 15G and 15)I 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 furthermore, this throttle valve lever portion 15J
A cylindrical body 15K, for example, is integrally provided above. An opening recess 15L is bored at the upper end of the cylinder 15, and the throttle body 15L 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, on the side of the opening to the opening recess 151° of the holder insertion hole 15M, that is, at the bottom of the four openings 15L,
A control protrusion 15F is provided that protrudes from the bottom. Further, a cover 16 is disposed on the sides and above the cylinder body 15 of the throttle body 15 with a gap between them, and specifically, the cover 16 is arranged between an annular portion 18A surrounding the cylinder body 15 on the side and a cover 16 on the cylinder body 15. This consists of an upper lid body 16B that covers the upper part of the carburetor, and this cover 16 is attached to the carburetor main body 10. Furthermore, the upper lid body 1
8B is provided with an adjustment concave portion 18C, and the adjustment portion 16C is provided with a control portion 16 for allowing the locking protrusion of the limiter cap, which will be described later, to rotate within a certain range.
1D and 18E, and a locking step 18F that projects into the opening recess 15L of the throttle body 15 is provided at the lower part of the upper lid 1θB.

And the throttle body! A needle 17 is movably arranged in the needle insertion hole 15N of No.
The fuel well 15B of the fuel control hole 13B is inserted into the fuel well A.
21 dollars 17
The upper part faces the holder insertion hole 15M side.

Further, a holder 18 is inserted into the holder insertion hole 15M of the throttle body 15, and a hole 18A is bored at the longitudinal axis of the holder 18 and inside the center from the top to the bottom. Opening recess 15 of holder 18
A cam portion 18B is inserted into the opening to L from the side of the holder 18.
The 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.

Further, reference numeral 18C is a locking protrusion provided to protrude from the holder 18, and this locking protrusion 18C is locked to the engagement of the upper lid body IB and the stepped portion 16F.

The adjustment screw 1 is inserted into the hole 18A of the holder 18.
8 is screwed on, and this adjustment screw! The lower end of 9 protrudes from the lower end of the holder 18 and comes into contact with the needle 17, and the upper end thereof protrudes from the upper part of the holder 18 and reaches the adjustment recess 18C of the cover 16 through the opening recess 15L of the throttle body 15.

Therefore, the fuel nozzle 13. Needle 17. Throttle body 15. Holder 18. The longitudinal axes of the adjusting screw 19 and the adjusting screw 19 are arranged substantially on the same straight line.

Furthermore, a holder spring 20 is arranged approximately concentrically around the outer periphery of the adjustment screw 18, one end of which is engaged with the cover 18, and the other end of which is engaged with the holder 18. As a result, the cam portion 18B of the holder 18 is elastically pressed against the control protrusion 15F of the throttle body 15, and the locking protrusion 18C of the holder 18 is pressed against the engagement and step portion 161F of the cover 16. A needle spring 21 is arranged approximately concentrically around the outer circumference of the needle 17, and the needle spring 21 elastically presses the upper end of the needle 17 against the lower end of the adjusting screw 18.

Reference numeral 22 denotes a throttle valve return spring, which is arranged approximately concentrically around the outer periphery of the bearing portion 15F of the throttle body 15. One end of the throttle valve return spring 22 is locked to the throttle body 15, and the other end is latched to the throttle body 15. It is secured to a stay plate 23 that covers the upper part 10A of the carburetor main body 10, so that the throttle body 15 is always biased with a force in the closing direction.

In addition, 24 is a stop screw that is opposed to the throttle valve lever part 15J, and by screwing this, the opening surfaces of the throttle valve parts 15C and 150 can be adjusted.

Next, its effect will be explained.

First, the fitting operation of the engine will be explained. The throttle body 15 is set to the minimum amount of air necessary to satisfy idling operation of the engine, and the 4th rI
! Shown in J. This amount of air is determined by the gap between the outer periphery of the plate-shaped throttle valve portions 15C and 15D of the throttle body 15 and the intake passage 11 and the hole area of the through hole 15G, and is determined by screwing the stop screw 24. This allows accurate adjustment of the amount of air.

On the other hand, the amount of fuel sucked out into the fuel well 15B from the fuel control hole 13B of the fuel nozzle 13 is determined by the needle l of the fuel control hole 13B? During such idling operation, the control protrusion 15F of the throttle body 15 is determined by the opening area of the cam part 18B of the holder 18.
Since the holder 18 and the adjusting screw 19 are in the lowest position, and the needle 17 is also in the lowest position, the opening of the fuel control hole 13B can be maintained at a small opening. It is something.

The opening of the smallest fuel control hole 13B is controlled by an adjustment screw! By screwing 9, the needle 17 can be moved independently of the cam portion of the holder 18, thereby making it possible to accurately correct the fuel during idling operation.

During such idling operation, the negative pressure generated in the intake passage 11 is absorbed through the engine-side through hole 15G of the throttle body 15.
This negative pressure acts on the fuel well 15B, and this negative pressure causes the fuel to be sucked out from the fuel control hole 13B into the fuel well 15B.
In this fuel well 15B, it mixes with the air flowing in through the air cleaner side through hole 15H to form a mixture, and this mixture is sucked into the intake passage 11 through the engine side through hole 15G.

Next, when the throttle body 15 is gradually opened, the throttle valve parts 15C and 150 open the intake passage 11, so that the amount of air is gradually increased.

On the other hand, according to the rotation of the throttle body 15, the rotation of the holder 18 is suppressed by the locking protrusion 18C and the locking step IEIF, so that the cam portion 18B of the holder 18 relative to the control protrusion 15F is The holder 18 and the adjustment screw 18 are moved to a lower position than the high position in the above state, and according to this, the holder 18 and the adjustment screw 18 gradually move upward against the spring force of the holder spring 20 in response to the rotation of the throttle body 15. . According to this, the needle 17 is moved by the adjusting screw 1 by the spring force of the needle spring 21.
3 moves upward in synchronization with the movement of fuel control hole 1.
This is the opening surface of 3B.

Then, as soon as the throttle body 15 is fully opened, the holder 1
Since the lowest position of the cam portion 18B of No. 8 comes into contact with the control protrusion 15F, the opening of the fuel control hole 13B can be made the largest, and fuel can be supplied in accordance with the maximum amount of air, thereby allowing the engine to operate at full throttle. can be achieved.

In addition, in recent years, synthetic resin materials are often used instead of electrical points to reduce the weight of carburetors, and the throttle body 15 and holder 18 are made of synthetic resin materials not only to reduce weight but also to reduce costs due to their complex shapes. Molding is preferable, and in such a case, the control protrusion 15F of the throttle body 15 is preferably made of a metal ball such as a steel ball. This is particularly preferable when the control protrusion 15F and the cam part 18B are made of a synthetic resin material during durability. Abrasion or galling may occur on the contact surface between the throttle body 15, which not only deteriorates the operating feeling of the throttle body 15 but also changes the lift characteristics with respect to the needle 17, resulting in poor performance. be.

Further, it is preferable that the synthetic resin materials of the throttle body 15 and the holder 18 are different from each other, and in particular, it is preferable that the coefficient of friction of the holder 18 is smaller than that of the throttle body 15 in order to improve the dynamic characteristics of the holder 18. It turned out to be something.

Furthermore, the test results showed that the through-holes 15G and 15H of the throttle body 15 were made to have the same shape as the first order, thereby achieving an effect in terms of performance. That is, the throttle body 15
When the throttle valve section 15C is in a low opening state (as shown in FIG. 4), such as when the throttle valve section 15C is idling, -
The through hole 15G on the side opens to the intake path 11 on the engine side (right side in the figure), while the through hole 15H on the other side opens to the intake path 11 on the air cleaner side (left side in the figure).

According to this, when the engine is operating at a low opening such as when the engine is idling, the negative pressure of the intake passage of the engine does not directly act on the through hole 15H on the other side, so air can flow into the fuel well 15B, and the fuel can flow into the fuel well 15B. In the well 15B, the fuel can be mixed well with the fuel sucked out from the fuel control hole 13B to form an air-fuel mixture, and in the throttle body 15, during high opening operation, both the through holes 15G and 15H have a high flow rate of intake air. Since it can be opened in the road 11, both page through holes 15G,
15H, the fuel in the fuel well 15B could be shared and supplied into the intake passage 11, thereby improving performance.

Further, the opening end of the adjustment recess 18C of the cover 16 is closed with the first closing member 50, and the annular gap between the circumference of the cylinder body 15 of the throttle body 15 and the inner circumference of the annular portion 18A of the cover 16 is elastically formed. By arranging the second closure member 51 made of material, the holder 18. which influences the movement of the needle 17 in particular. The intrusion of water, dirt, etc. into the operating parts of the adjusting screw 19 and needle 17 can be completely prevented, and the carburetor is particularly suitable for use in places with poor working environments such as general-purpose engines.

Further, the upper end of the adjustment screw 18 is placed in the adjustment recess 16C of the cover 16, and the limiter cap 52 is fitted into one end of the adjustment screw 18 and has a locking protrusion 52A on the outside thereof. - a control unit 18D in which the locking protrusion 52A of the cap 52 is provided in the adjustment recess 18C;
18H, the range in which the limiter cap 52 can rotate is limited to the locking protrusion 5 of the limiter cap 52.
The limiter cap 5 can be limited to a certain range until 2A contacts the control part 18D or 16E, and the limiter cap 5 can be set after setting the adjustment screw 18 during production of the carburetor.
2 into the adjustment screw 19, even if a general user turns the adjustment screw 19, the rotation range is predetermined, so there is no need to worry about impairing engine performance.

Further, the bearing parts 15E and 15F of the throttle body 15 use the valve inner cylinder 12 as a reference fitting hole, and the holder 18
The adjusting screw 18 is based on the holder fitting hole 15M of the throttle body 15, and the annular portion 16A and the locking stepped portion 16F of the cover 16 are based on the throttle body 15 or the holder 18.

That is, the throttle body 15. Holder 18. Adjustment screw 19. The origin of all the references for the cover IB is located in the valve inner cylinder 12 of the carburetor main body 10. In particular, when attaching the stay plate 23 and the cover 16 to the carburetor main body 10, a positioning post 54 is provided protrudingly on the upper side 10A of the carburetor main body 10, and the positioning post 54 has a positioning hole in the stay plate 23. 23A and the positioning hole 18G of the cover 16, and then screw the upper part thereof with the screw 55 to connect the cover 18, the adjustment screw 19, and the holder 1.
8. The relationship between the throttle body 15 and the support hole 23B of the stay plate 23 and the bearing portion 15F of the throttle body 15
It is possible to accurately determine the positional relationship between the

〔Effect of the invention〕

According to the rotary throttle valve type carburetor of the present invention, the following effects can be achieved.

■The fuel sucked out into the intake tract is high (the intake pressure is not reduced) because the intake tract negative pressure generated in the intake tract acts directly on the fuel control hole through the through hole and fuel well. The negative pressure can be effectively applied to the fuel control hole, and the fuel sucked out from the fuel control hole mixes well with the air from the through hole on the air cleaner side flowing down in the fuel well. Since it is placed relatively centrally in the intake duct, it can greatly improve the atomization characteristics of the fuel and improve the engine's running performance.

■The airflow flows down both sides of the intake tract by the plate-shaped throttle valve part of the throttle body, and the fuel sucked directly into the intake tract from the fuel control hole is surrounded by the airflow, so the airflow flows down the intake tract. This makes it difficult for the wall surface flow to occur, and improves the atomization performance of the air-fuel mixture.

■Since the fuel control hole opens directly into the intake passage through the fuel well, the pressure applied to the fuel control hole can be maintained at a higher level than when the fuel control hole is placed downstream of the throttle valve. Therefore, even if the carburetor body is tilted, it is not easily affected by the gravitational head of the fuel due to the tilt, and the toughness of the engine against tilted operation can be improved.

■If the throttle body and holder are made of synthetic resin, and the control protrusion of the throttle body is made of a ball made of metal material, the rotational operability of the throttle body and the dynamic characteristics of the holder can be smoothly controlled. If the coefficient of friction of the synthetic resin material forming the holder is smaller than the coefficient of friction of the synthetic resin material forming the throttle body, the dynamic characteristics of the holder relative to the holder fitting hole of the throttle body can be smoothed, and the rotation of the throttle body can be achieved. The followability of the needle can be improved.

■Two through holes are drilled in the shaft of the throttle body to connect the fuel well and the intake passage, and when the throttle body is opened at a low opening, the first through hole opens into the intake passage on the engine side, and the first through hole opens into the intake passage on the engine side. When the second through hole is opened to the intake path on the air cleaner side, air is supplied into the fuel well from the second through hole that opens to the air cleaner side intake path during idling operation, and the mixture is mixed in the fuel well. The atomization characteristics can be significantly improved because the atomization characteristics are formed, and the fuel is supplied from the re-penetration hole in the throttle body in the high opening range, making it possible to supply the necessary and sufficient amount of fuel. It is something.

■ By arranging the longitudinal axes of the throttle body, fuel nozzle, needle, holder, and adjustment screw on substantially the same straight line, the point of application of the force of each of the above parts becomes the same, so that the remaining parts, especially those with respect to the throttle body, This made it possible to improve the dynamic characteristics of the

■The throttle valve return spring, needle spring, and holder spring are arranged around the outer periphery of the throttle body, needle, and holder, and the center points of each spring are arranged approximately on the same straight line, which prevents the needle and holder from tipping over as much as possible. Moreover, the operation could be performed smoothly.

■Since the gap between the cylindrical body of the throttle body and the annular part of the upper lid body or the opening of the adjustment recess, which is the part that opens to the atmosphere, is closed with a closing member, the needle for fuel control, in particular,
This prevents water and dirt from entering the sliding parts of the holder, adjustment screw, and maintains excellent performance over a long period of time.

■A limiter cap was attached to the adjustment screw, and a control unit was installed in the adjustment recess of the upper lid, which allowed the adjustment range of the adjustment screw to be restricted to a certain adjustment range, so it was similar to a general-purpose engine, and relatively inexperienced in handling the machine. This makes adjustment work easier for women and others.

Since the installation positions of the cover and stay plate are determined by the positioning bosses on the carburetor body, the throttle body and upper lid body can be accurately positioned with respect to the valve inner cylinder of the carburetor body, and the throttle body This makes it possible to improve the operation of the holder and the adjustment screw.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a conventional rotary throttle valve type carburetor, FIG. 2 is a vertical cross-sectional view showing an embodiment of the rotary throttle valve type carburetor according to the present invention, and FIG. 2 is a top plan view, and FIG. 4 is a cross-sectional view of IT-17 in FIG. 2. 10. Carburetor body 12. , Valve inner cylinder 13, Fuel nozzle 13B, Fuel control hole 15, Throttle body 15A, Shaft 15
F., control protrusion 16. ,,,Cover 1? ,,
,, Needle 16, ,, Holder I11.
．． ．． ．． Adjustment screw h40

Claims (12)

[Claims] (1) A carburetor main body 10 in which an intake passage 11 passes through, and a cylindrical throttle valve guide cylinder 12 is perforated substantially perpendicularly to the intake passage 11 and across the intake passage 11; 1
A fuel control hole 13B is provided vertically in the intake passage 11 from the bottom of the fuel control passage 13A, and one end of the fuel control passage 13A passing through the interior is connected to the fuel flow passage 14, and a fuel control hole 13B is opened from the fuel control passage 13A into the intake passage 11. A drilled fuel nozzle 13; and a fuel well hole 1 having a gap S around the outer periphery of the fuel nozzle 13.
5B and a shaft portion 15A that opens at least into the intake passage 11; and a plate-shaped throttle valve portion 15 that extends laterally from the shaft portion 15A and can control opening and closing of the intake passage 11.
C, 15D, and the fuel nozzle 13 is bored in the shaft portion 15A.
Through holes 15G and 15H that communicate gap S and intake passage 11
, bearing parts 15E and 15F which are located at both the upper and lower ends of the shaft part 15B and are rotatably fitted into the throttle valve guide cylinder 12, and a throttle valve lever part which is above the bearing part 15F and projects from the carburetor main body 10. 15J, and a holder fitting hole 15M and a needle fitting hole 15N are connected and drilled below the upper opening of the cylinder 15 connected above the throttle valve lever part 15J on the side of the bearing part 15E, and the holder is fitted into the cylinder body 15J. a control protrusion 15P that protrudes laterally from the opening of the hole 15M; a control protrusion of the throttle body 15 that is movably disposed within the holder fitting hole 15M of the throttle body 15; 15
A holder 18 having a cam portion 18B and a locking protrusion 18C corresponding to P; is movably disposed within the needle insertion hole 15N of the throttle body 15, and one end thereof is inserted into the fuel control passage 13A of the fuel nozzle 13. The needle 17 and the vaporizer main body 10
An upper lid body 16 is disposed on the open end of the throttle valve guide cylinder 12 and covers the vicinity of the upper part of the cylinder body 15K of the throttle body 15.
B, and the holder 1 is installed vertically below the upper lid body 16B.
a cover 16 having a locking step 16F that prevents rotation of the holder 18 in correspondence with the locking protrusion 18C of No. 8; an adjustment screw 19 that is screwed onto the holder 18 and has one end facing the needle 17; The rotating throttle valve part of the carburetor. (2) The throttle body and the holder are formed of a synthetic resin material, and the control protrusion 15P of the throttle body 15
2. The rotary throttle valve carburetor according to claim 1, wherein the rotary throttle valve portion is a sphere made of a metal material. (3) Two through holes are bored, and the first through hole 15G
The throttle valve portions 15C and 15D of the throttle body 15 open to the engine-side intake passage 11 when the opening degree is low, and the second
The through hole 15H is the throttle valve part 15C of the throttle body 15,
15. The rotary throttle valve carburetor according to claim 1, wherein 15D opens into the air intake passage 11 on the air cleaner side when the opening degree is low. (4) The throttle body and the holder are made of a synthetic resin material, and the friction coefficient of the synthetic resin material forming the holder 18 is smaller than the friction coefficient of the synthetic resin material forming the throttle body 15. The rotary throttle valve type carburetor according to item 1. (5) A carburetor main body 10 in which an intake passage 11 passes through, and a cylindrical throttle valve inner cylinder 12 is bored substantially perpendicularly to the intake passage 11 and across the intake passage 11; 1
A fuel control hole 13B is provided vertically in the intake passage 11 from the bottom of the fuel control passage 13A, and one end of the fuel control passage 13A passing through the interior is connected to the fuel flow passage 14, and a fuel control hole 13B is opened from the fuel control passage 13A into the intake passage 11. A drilled fuel nozzle 13; and a fuel well hole 1 having a gap S around the outer periphery of the fuel nozzle 13.
5B and a shaft portion 15A that opens at least into the intake passage 11; and a plate-shaped throttle valve portion 15 that extends laterally from the shaft portion 15A and can control opening and closing of the intake passage 11.
C, 15D, and the fuel nozzle 13 is bored in the shaft portion 15A.
Through holes 15G and 15H that communicate gap S and intake passage 11
, bearing parts 15E and 15F which are located at both the upper and lower ends of the shaft part 15B and are rotatably fitted into the throttle valve inner cylinder 12, and a throttle valve lever part which is above the bearing part 15F and projects from the carburetor main body 10. 15J, a holder fitting hole 15M and a needle fitting hole 15N are connected and drilled below the upper opening of the cylindrical body 15K connected above the throttle valve lever part 15J on the bearing part 15E side. a throttle body 15 having a control protrusion 15P that protrudes laterally from an opening of the throttle body 15;
A holder 18 having a cam portion 18B and a locking protrusion 18C corresponding to P; is movably disposed within the needle insertion hole 15N of the throttle body 15, and one end thereof is inserted into the fuel control passage 13A of the fuel nozzle 13. The needle 17 and the vaporizer main body 10
An upper lid body 16 is disposed on the open end of the inner cylinder 12 of the throttle valve part and covers the vicinity of the upper part of the cylinder body 15 of the throttle body 15.
B, and the holder 1 is installed vertically below the upper lid body 16B.
a cover 16 having a locking step 16F that prevents rotation of the holder 18 in correspondence with the locking protrusion 18C of No. 8; an adjustment screw 19 that is screwed onto the holder 18 and has one end facing the needle 17; It consists of a throttle body 15, a fuel nozzle 13, a needle 17, and a holder 18.
, and the adjusting screw 19, whose longitudinal axes are arranged substantially on the same straight line. (6) A carburetor main body 10 in which an intake passage 11 passes through, and a cylindrical throttle valve inner cylinder 12 is bored substantially orthogonally to the intake passage 11 and across the intake passage 11; 1
A fuel control hole 13B is provided vertically in the intake passage 11 from the bottom of the fuel control passage 13A, and one end of the fuel control passage 13A passing through the interior is connected to the fuel flow passage 14, and a fuel control hole 13B is opened from the fuel control passage 13A into the intake passage 11. A drilled fuel nozzle 13; and a fuel well hole 1 having a gap S around the outer periphery of the fuel nozzle 13.
5B and a shaft portion 15A that opens at least into the intake passage 11; and a plate-shaped throttle valve portion 15 that extends laterally from the shaft portion 15A and can control opening and closing of the intake passage 11.
C, 15D, and the fuel nozzle 13 is bored in the shaft portion 15A.
Through holes 15G and 15H that communicate gap S and intake passage 11
, bearing parts 15E and 15F which are located at both the upper and lower ends of the shaft part 15B and are rotatably fitted into the throttle valve inner cylinder 12, and a throttle valve lever part which is above the bearing part 15F and projects from the carburetor main body 10. 15J, a holder fitting hole 15M and a needle fitting hole 15N are connected and drilled below the upper opening of the cylindrical body 15K connected above the throttle valve lever part 15J on the bearing part 15E side. a throttle body 15 having a control protrusion 15P that protrudes laterally from an opening of the throttle body 15;
A holder 18 having a cam portion 18B and a locking protrusion 18C corresponding to P; is movably disposed within the needle insertion hole 15N of the throttle body 15, and one end thereof is inserted into the fuel control passage 13A of the fuel nozzle 13. The needle 17 and the vaporizer main body 10
An upper lid body 16 is disposed on the open end of the throttle valve guide cylinder 12 and covers the vicinity of the upper part of the cylinder body 15K of the throttle body 15.
B, and the holder 1 is installed vertically below the upper lid body 16B.
a cover 16 having a locking step 16F that prevents rotation of the holder 18 in correspondence with the locking protrusion 18C of No. 8; an adjustment screw 19 that is screwed onto the holder 18 and has one end facing the needle 17; a throttle valve return spring 22 that biases the throttle valve parts 15C and 15D of the throttle body 15 in the closing direction; and a needle 1
a needle spring 21 that presses the end of the holder 18 against the end of the adjustment screw 19 ; A rotary throttle valve type carburetor comprising: a holder spring 20 that presses against the locking step portion 16F; (7) The rotating throttle valve type carburetor according to claim 6, wherein the throttle valve return spring, needle spring, and holder spring are arranged substantially on the same straight line. (8) The throttle valve return spring is the throttle body 1
5, one end of which is locked to the stay plate 23 that closes the upper opening of the throttle valve guide cylinder 12 or the carburetor body 10, and the other end is locked to the throttle body 15. A rotary throttle valve type carburetor according to claim 6. (9) The holder spring has one end attached to the cover 1.
6, and the other end is locked to a holder 18. (10) A carburetor main body 10 in which an intake passage 11 passes through, and a cylindrical throttle valve guide cylinder 12 is bored substantially perpendicular to the intake passage 11 and across the intake passage 11; A fuel control hole 13B is provided upright in the intake passage 11 from the bottom of the fuel control passage 12, and one end of the fuel control passage 13A passing through the inside is connected to the fuel flow passage 14, and a fuel control hole 13B is opened from the fuel control passage 13A into the intake passage 11. A drilled fuel nozzle 13; and a fuel well hole 1 having a gap S around the outer periphery of the fuel nozzle 13.
5B and a shaft portion 15A that opens at least into the intake passage 11; and a plate-shaped throttle valve portion 15 that extends laterally from the shaft portion 15A and can control opening and closing of the intake passage 11.
C, 15D, and the fuel nozzle 13 is bored in the shaft portion 15A.
Through holes 15G and 15H that communicate gap S and intake passage 11
, bearing parts 15E and 15F which are located at both the upper and lower ends of the shaft part 15B and are rotatably fitted into the throttle valve guide cylinder 12, and a throttle valve lever part which is above the bearing part 15F and projects from the carburetor main body 10. 15J, a holder fitting hole 15M and a needle fitting hole 15N are connected and drilled below the upper opening of the cylindrical body 15K connected above the throttle valve lever part 15J on the bearing part 15E side. a throttle body 15 having a control protrusion 15P that protrudes laterally from an opening of the throttle body 15;
A holder 18 having a cam portion 18B and a locking protrusion 18C corresponding to P; is movably disposed within the needle fitting hole 15N of the throttle body 15, and one end thereof is inserted into the fuel control passage 13A of the fuel nozzle 13. The needle 17 and the vaporizer main body 10
An upper lid body 16 is disposed on the open end of the throttle valve guide cylinder 12 and covers the vicinity of the upper part of the cylinder body 15K of the throttle body 15.
B, and the holder 1 is installed vertically below the upper lid body 16B.
A cover 16 has a locking step portion 16F that prevents rotation of the holder 18 in correspondence with the locking protrusion 18C of the holder 18; Adjustment screw 19 penetrating into adjustment recess 16C provided in upper lid body 16B of No. 16
and; a first closing member 5 that covers the adjustment recess 16C of the cover 16;
0 and the outer periphery of the cylindrical body 15K of the throttle body 15 and the upper lid body 16B
a second closing member 52 disposed in an annular gap with an annular portion 16A; (11) A carburetor main body 10 in which an intake passage 11 passes through, and a cylindrical throttle valve inner cylinder 12 is bored substantially orthogonally to the intake passage 11 and across the intake passage 11; A fuel control hole 13B is provided upright in the intake passage 11 from the bottom of the fuel control passage 12, and one end of the fuel control passage 13A passing through the inside is connected to the fuel flow passage 14, and a fuel control hole 13B is opened from the fuel control passage 13A into the intake passage 11. A drilled fuel nozzle 13; and a fuel well hole 1 having a gap S around the outer periphery of the fuel nozzle 13.
5B and a shaft portion 15A that opens at least into the intake passage 11; and a plate-shaped throttle valve portion 15 that extends laterally from the shaft portion 15A and can control opening and closing of the intake passage 11.
C, 15D, and the fuel nozzle 13 is bored in the shaft portion 15A.
Through holes 15G and 15H that communicate gap S and intake passage 11
, bearing parts 15E and 15F which are located at the upper and lower ends of the shaft part 15B and are rotatably fitted into the throttle valve inner cylinder 12, and a throttle valve lever part which is above the bearing part 15F and projects from the carburetor main body 10. 15J, a holder fitting hole 15M and a needle fitting hole 15N are connected and drilled below the upper opening of the cylindrical body 15K connected above the throttle valve lever part 15J on the bearing part 15E side. a throttle body 15 having a control protrusion 15P that protrudes laterally from an opening of the throttle body 15;
A holder 18 having a cam portion 18B and a locking protrusion 18C corresponding to P; is movably disposed within the needle insertion hole 15N of the throttle body 15, and one end thereof is inserted into the fuel control passage 13A of the fuel nozzle 13. The needle 17 and the vaporizer main body 10
An upper lid body 16 is disposed on the open end of the inner cylinder 12 of the throttle valve part and covers the vicinity of the upper part of the cylinder body 15K of the throttle body 15.
B, and the holder 1 is installed vertically below the upper lid body 16B.
a cover 16 having a locking step 16F that prevents rotation of the holder 18 in correspondence with the locking protrusion 18C of No. 8; an adjustment screw 19 that is screwed onto the holder 18 and has one end facing the needle 17; A limiter cap 52 that is fitted into the end of the adjustment screw 19 protruding into the adjustment recess 16C of the upper lid body 16B of the cover 16 and has a locking protrusion 52A on the side is provided in the adjustment recess 16C of the cover 16. A rotary throttle valve part carburetor which allows rotation only within a certain rotation range by parts 16D and 16E. (12) The rotary throttle valve carburetor according to claim 1, wherein the cover and the stay plate are positioned by a positioning boss 16G that protrudes from the carburetor main body.