JPS62103452A - Diaphragm type carburetor - Google Patents

Abstract

PURPOSE:To provide a carburetor which may be simply assembled, by stacking a jet block, a diaphragm and a cover successively in the mentioned order on a carburetor body in a diaphragm type carburetor. CONSTITUTION:When various component parts of a diaphragm carburetor are assembled in a carburetor body provided with a throttle valve 4, a venturi 2, a main nozzle chamber 5, a slow fuel chamber 25 and the like, a jet block 20 provided therein with a main jet 26, a slow jet 27 and the like is laid. Then a diaphragm 34 is set on the outer surface of the jet block 20, and further, a cover 36 is stacked on the outer surface of the diaphragm 34. Finally they are secured together as one unit body by means of screws.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a carburetor for controlling air-fuel mixture supplied to an engine.

Generally, a float type carburetor forms a constant liquid level in the float chamber formed by the carburetor body and the float chamber body through the cooperation of the valve seat, float valve, and float, and the lower part of the carburetor body. The diaphragm and cover are arranged in a stacked manner, the carburetor main body and the diaphragm form a pressure receiving chamber, the diaphragm and the cover form a popular chamber, and the diaphragm is moved in response to the pressure from the nozzle opening into the intake duct. There is a diaphragm type carburetor in which the float valve is opened from the valve seat by the movement of the diaphragm, and fuel is introduced into the pressure receiving chamber and discharged from the nozzle hole.The present invention relates to the diaphragm type carburetor described later. .

``Prior art'' A conventionally commonly used diaphragm type carburetor is formed by laminating a carburetor body through which an intake passage passes through, a diaphragm covering a concave portion of the carburetor body, and a cover covering the diaphragm. A main fuel system passage, a slow fuel system passage, a valve seat for supplying and stopping fuel 1, and a float valve, which perform the important functions of the carburetor, are arranged in the carburetor body.

[Problems to be Solved by the Invention] The conventional diaphragm type carburetor has the following problems.

■Main fuel system passage, slow fuel system passage in the carburetor body,
and/The fuel passage including the help sheet is placed in an extremely narrow space, and there are restrictions on the casting of the carburetor body, and during processing, each passage and chamber may become electrically conductive due to cavities generated during casting. According to this, performance cannot be guaranteed.

(2) The above also impedes weight reduction of the carburetor main body.

■Since various control members are incorporated into the carburetor body, it is necessary to replace the carburetor body when replacing these parts, which places a heavy economic burden on the user.

■Easy to maintain since various control members are installed from one side of the carburetor body.

It has the following problems.

"Means for Solving the Problems" In view of the above-mentioned problems, the diaphragm type carburetor according to the present invention is constructed as follows.

In other words, an intake passage passes through the carburetor body, and the intake passage is equipped with a throttle valve for opening and closing the intake passage; a valve seat connected to a fuel passage; a float valve for controlling the opening and closing of the valve seat; Old opening/closing action to pulp! j, a jet block having a float arm; a diaphragm disposed corresponding to the flow door; and a cover covering the diaphragm; A diaphragm and a cover are laminated in sequence, and most of the passages and chambers are formed by casting during casting, and the parts that control the performance and functions of the carburetor are divided and placed in the jet block. .

"Embodiments" Hereinafter, embodiments of the diaphragm type carburetor of the present invention will be described with reference to FIGS. 1 to 4.

1 is a carburetor main body through which an intake passage 2 passes, and a throttle valve 4 is disposed in the intake passage 2, which is attached to a throttle valve shaft 3 rotatably mounted on the carburetor body 1. The opening and closing of the intake passage 2 is controlled by the rotation of the throttle valve 4. One side of the carburetor main body has a recess in which a jet block, which will be described later, is arranged, and this recess includes a main fixed jet fuel chamber recess 5, a main variable jet fuel chamber recess 6, a slow fuel chamber recess 7, and a fuel fitting passage 9 connected to the fuel passage 8.
and a cast recess 10 are provided.

A main nozzle hole 11 connected to the intake passage 2 is opened at the bottom of the fuel chamber recess 5 for the main fixed jet.

A check pulp 12 is disposed in the main nozzle hole 11, which is opened by the intake passage negative pressure applied to the main nozzle hole 11.

Note that 13 is a plate for attaching the check pulp 12 to the carburetor main body l.

Further, the fuel chamber recess 6 for the main variable jet and the fuel chamber recess 5 for the main fixed jet are communicated through a main control passage 14, and a main adjustment screw 15 for variably controlling the passing fuel is moved in the control passage. Can be placed freely.

A bypass hole 16 corresponding to the throttle valve 4 is bored in the Sislow River fuel chamber 1 recess 7, and the slow fuel chamber recess 7 is connected to a pilot outlet hole 17 that opens into the intake path 2 downstream of the throttle valve 4. A slow control passage 18 is connected thereto, and a slow adjustment screw 18 for controlling the speed of the air-fuel mixture passing through the pilot outlet hole 17 is movably disposed in the slow control passage 18.

Reference numeral 20 denotes a jet block that is fitted into a recess in the carburetor main body 1, and the main fixed jet fuel chamber recess 5, the main variable jet fuel chamber recess 6,
A flat portion 21 covering the slow fuel chamber recess 7 and a valve seat 22 fitted into the fuel fitting passage 9 are arranged,
By fitting this jet block 20 into the recess of the carburetor main body 1, a main fixed jet fuel chamber 23, a main variable jet fuel chamber 24, and a slow fuel chamber 25 are respectively formed.

Further, a fixed main jet 2B, a fixed slow jet 27, and a main fuel passage 28 are bored through both end faces of the jet block 20, and the fixed main jet 26 opens into the main fixed jet fuel chamber 23, and the fixed slow jet 27 opens into the main fixed jet fuel chamber 23. The main fuel passage 28 opens to the slow fuel chamber 25, and the main fuel passage 28 opens to the main variable jet fuel chamber 24.

Further, on the other side of the jet block 20, there is a float valve 29 disposed within the valve seat 22, and this float valve 29 has a float arm 31 rotatably supported on a shaft 30 supported by the jet block 20.
The float valve 2B always urges the valve seat 22 in the closing direction by the spring force of the spring 32 that presses the float arm 31. Further, 33 is a screw for screwing the jet block 20 onto the carburetor main body l.

Next, 34 is a diaphragm made of an elastic material 111 such as rubber, which is placed over the jet block 20. A substantially central portion of the diaphragm 34 abuts the float arm 31 at a position opposite to the engagement point of the float valve 29 .

36 is a cover that covers the diaphragm 34, and an air hole 37 is bored in the cover 36. And the vaporizer body 1
Jet block 20, diaphragm 34, cover 3
6. are sequentially stacked.

As a result, as described above, the main fixed jet fuel chamber 23
, main variable jet fuel chamber 24, slow fuel chamber 2
5 is formed, a pressure receiving chamber 38 is formed by the other side of the jet block 20 and the diaphragm 34, and an atmospheric chamber 38 is formed by the diaphragm 34 and the cover 36. Further, 40 is a water drain hole provided in the cast-out recess 10 of the carburetor main body l.

Next, the operation will be explained. First, when the throttle valve 4 is operated at a low opening, the pilot outlet hole 17 and the bypass hole 16 open to the intake passage 2 on the engine side from the throttle valve 4. A negative airway pressure acts on the holes 17,16. According to this, the negative pressure in the intake passage acts in the pressure receiving chamber 38 via the slow fuel chamber 25 and the fixed slow jet 27, and this pressure causes the diaphragm 34 shown in FIG. 2 to move downward in the figure. According to this, the foot arm 31 rotates counterclockwise in the figure against the force of the spring 32, and in response to the negative pressure, moves the float valve 29 away from the valve seat 22 and opens the float valve 29 from the fuel passage 8. This fuel flows through the bypass hole 18 and the pilot outlet hole 1 through the reverse flow to which the negative pressure was introduced.
7 into the intake passage 2 to operate the engine.

In order to control the fuel limit during such low opening operation, the amount of liquid in the pilot outlet hole can be adjusted by moving the slow adjustment screw 19.

Next, when the throttle valve 4 is further opened and is fully opened, the negative pressure in the intake passage 2 will further increase, and this increased intake passage negative pressure will be transferred through the main fixed jet fuel chamber 23 and the fixed main jet 26. The diaphragm 34 further rotates counterclockwise due to this large intake passage negative pressure, further separating the float valve 28 from the valve seat 22, and directing a larger flow rate of fuel into the pressure receiving chamber 3.
8, thereby providing a flow rate suitable for medium and high opening operation.

Incidentally, the supplementary IF of the fuel flow rate during such mid-to-high opening operation can be variably adjusted as appropriate by moving the main adjustment screw 15.

"Effects of the Invention J As described above, according to the diaphragm type carburetor of the present invention, there is a main body of the carburetor whose interior is penetrated by an intake passage, and the intake passage is equipped with a throttle valve for opening and closing the intake passage; A jet block having a valve seat connected to a passage, a float valve that controls opening and closing of the valve seat, and a float arm that provides opening and closing operations to the float valve; A diaphragm disposed corresponding to the float arm; A diaphragm Since the carburetor main body, jet block, diaphragm, and cover are laminated in order, the jet block can be cast from both sides, making the overall product lighter and faster, as well as eliminating cavities during casting. 11- It is possible to completely prevent this, making it possible to significantly reduce product costs.

■ An intake passage L' passes through the interior, and the intake passage includes a carburetor body equipped with a throttle box that opens and closes the intake passage; a valve seat connected to the fuel passage; and a float valve that controls the opening and closing of the valve seat. a jet block having a float arm that opens and closes the pulp; a diaphragm disposed corresponding to the float arm; and a cover covering the diaphragm, which includes the vaporizer main body, the jet block, and the diaphragm. , cover are sequentially stacked, and the main fixed jet fuel chamber recess, the main variable jet fuel chamber recess, and the slow combustion table 1 chamber recess provided on the side of the carburetor body corresponding to the jet block are connected to the jet block. By closing, the main fixed jet fuel chamber, main variable jet fuel chamber, and slow fuel chamber were formed independently, so the shape of each chamber was improved compared to conventional machining. This is preferable in product design and vaporizer settings because it greatly increases the design freedom in terms of volume.Furthermore, since the chambers are closed by a jet pro-nk, each chamber can be closed with a plug. There is no need for this.

■The carburetor body has an intake passage passing through the inside, and the intake passage is equipped with a throttle valve that opens and closes the intake passage; a valve seat connected to the fuel passage; a float valve that controls the opening and closing of the valve seat; a jet block having a float arm that provides an opening/closing action to the valve; a diaphragm disposed corresponding to the float arm; and a cover that covers the diaphragm, and the carburetor body, the jet block, the diaphragm, and the cover are sequentially connected In addition to stacking, the jet pro-nk also has a fixed main jet that opens into the main fixed jet fuel chamber, a main fuel passage that opens into the main variable jet fuel chamber, and a fixed slow jet that opens into the slow fuel chamber. Functional parts can be consolidated, and maintenance work has become easier because all that is required for maintenance is to remove the jet block and inspect each control jet, fuel control, etc. Furthermore, maintenance can be performed from both sides of the jet block. This greatly improves maintainability.

■The main adjustment screw is placed in the main control passage that communicates the main variable jet fuel chamber and the main fixed jet fuel chamber, and the slow control screw is connected from the slow fuel chamber to the pilot out-left hole on the downstream side of the throttle valve. Since the slow adjustment screw was placed in the passage, the main system,
The adjustment work for the slow speed system has been further improved.

■The fuel chamber for the main fixed jet, the fuel chamber for the main variable jet, the slow fuel chamber, and the casting chamber are formed independently, and a drain hole is provided in the casting chamber. When water enters the room, it can be immediately drained to the outside through the drain hole, resulting in a significant improvement in corrosion resistance.

[Brief explanation of drawings]

The figures show an embodiment of the diaphragm type carburetor according to the present invention.
IT! ! 3 is a side view of FIG. 1, and FIG. 4 is a side view of only the carburetor body. 190. Vaporizer main body, 500. Fuel chamber recess for fixed jet, 681. Fuel chamber recess for main variable jet,
700. Slow fuel chamber recess, 10, Casting recess, +5. ,,main adjustment screw,19. ,,
Throw adjustment screw, 20, jet block,
23. ,,Main Gou jet fuel chamber, 24. ,
, main variable jet fuel chamber, 25. ,, slow fuel chamber, 2E1. ,,main jet, 27. ,, fixed slow jet, 29. ,, float valve, 34
,,Diaphragm, 3B,,Cover,38,,,
Pressure receiving chamber, 39. ,,atmospheric chamber, 40. ,. It is a water drain hole. nu / Q $ 39 μ ri 9

Claims (1)

[Claims] 1. A carburetor body through which an intake passage passes through, and the intake passage is equipped with a throttle valve for opening and closing the intake passage; a valve seat connected to a fuel passage; and a carburetor body for opening and closing the valve seat. a jet block having a float valve to be controlled and a float arm that gives an opening/closing action to the float valve; a diaphragm disposed corresponding to the float arm; and a cover covering the diaphragm; , diaphragm, and cover are laminated in sequence. 2. A carburetor body through which an intake passage passes through, and the intake passage is equipped with a throttle valve for opening and closing the intake passage; a valve seat connected to a fuel passage; a float valve for controlling the opening and closing of the valve seat; a jet block having a float arm that provides an opening/closing action to the float valve; a diaphragm disposed corresponding to the float arm; and a cover that covers the diaphragm, and the carburetor body, the jet block, the diaphragm, and the cover are connected to each other. By sequentially stacking the main fixed jet fuel chamber recess, the main variable jet fuel chamber recess, and the slow fuel chamber recess provided on the side corresponding to the jet block of the carburetor body with the jet block, the main is fixed. A diaphragm carburetor that independently forms a jet fuel chamber, a main variable jet fuel chamber, and a slow fuel chamber. 3. A carburetor body through which an intake passage passes through, and the intake passage is equipped with a throttle valve for opening and closing the intake passage; a valve seat connected to a fuel passage; and a float valve for controlling opening and closing of the valve seat; a jet block having a float arm that provides an opening/closing action to the float valve; a diaphragm disposed corresponding to the float arm; and a cover that covers the diaphragm, and the carburetor body, the jet block, the diaphragm, and the cover are connected to each other. The jet block is sequentially stacked and further includes a fixed main jet that opens into the fuel chamber for the main fixed jet,
A diaphragm carburetor equipped with a main fuel passage that opens into the main variable jet fuel chamber and a fixed slow jet that opens into the slow fuel chamber. 4. A carburetor body through which an intake passage passes through, and the intake passage is equipped with a throttle valve for opening and closing the intake passage; a valve seat connected to a fuel passage; a float valve for controlling opening and closing of the valve seat; a jet block having a float arm that provides an opening/closing action to the float valve; a diaphragm disposed corresponding to the float arm; and a cover that covers the diaphragm, and the carburetor body, the jet block, the diaphragm, and the cover are connected to each other. By sequentially stacking the main fixed jet fuel chamber recess, the main variable jet fuel chamber recess, and the slow fuel chamber recess provided on the side corresponding to the jet block of the carburetor body with the jet block, the main is fixed. A jet fuel chamber, a main variable jet fuel chamber, and a slow fuel chamber are formed independently, and a main adjustment screw is placed in the main control passage that communicates the main variable jet fuel chamber with the main fixed jet fuel chamber. In addition, a diaphragm type carburetor has a slow adjustment screw arranged in a slow control passage that connects the slow fuel chamber to the pilot outlet hole on the downstream side of the throttle valve. 5. A carburetor body through which an intake passage passes through, and the intake passage is equipped with a throttle valve for opening and closing the intake passage; a valve seat connected to a fuel passage; a float valve for controlling opening and closing of the valve seat; a jet block having a float arm that provides an opening/closing action to the float valve; a diaphragm disposed corresponding to the float arm; and a cover that covers the diaphragm, and the jet block, the jet block, the diaphragm, and the cover. Blocking with the jet block the main fixed jet fuel chamber recess, the main variable jet fuel chamber recess, the slow fuel chamber recess, and the cast recess, which are sequentially stacked and provided on the side of the carburetor body corresponding to the jet block. A diaphragm type carburetor in which a main fixed jet fuel chamber, a main variable jet fuel chamber, a slow fuel chamber, and a casting chamber are formed independently, and a drain hole is further provided in the casting chamber. .