JP4106591B2 - Vaporizer fuel cutoff valve mounting structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a fuel cutoff valve mounting structure provided in a carburetor for a general purpose engine, and more particularly to a fuel cutoff valve mounting structure in a synthetic resin fuel container provided under a fuselage having a sideways intake passage. .
[0002]
[Prior art]
It is widely known that a carburetor for supplying fuel to an engine includes means for preventing a diesel phenomenon in which fuel is continuously supplied even after the key switch is turned off to stop the engine and the engine is rotated. It is known that a carburetor for a general-purpose engine is provided with a means for preventing a diesel effect, and a general example thereof is disclosed in Japanese Patent Application Laid-Open No. 11-50913.
[0003]
That is, a float is placed under a fuselage having a sideways intake passage, a fuel container is mounted, and the fuel passage is extended vertically in a columnar body disposed at the center and extending downward from the fuselage. The lower end inlet of this fuel passage is opened and closed by an electromagnetically driven fuel shut-off valve that is linked to the on / off of the key switch.
[0004]
FIG. 4 is a view showing an example of the diesel fueling prevention means provided in the conventional general-purpose engine carburetor. A fuel cutoff valve 53 is provided at the lower end of a columnar body 51 having a fuel passage 52 extending in the vertical direction. The upper end of the valve body 54 is fitted with an O-ring 57 while maintaining fluid tightness, and the mounting cylinder 60 projecting from the housing 59 of the solenoid actuator 58 of the fuel cutoff valve 53 is screwed into the lower end of the valve body 54. Are combined.
[0005]
The inside of the valve main body 54 forms a valve chamber 55, a valve seat 56 is provided at the top thereof, and a main jet 63 is attached to the peripheral side wall. The mounting cylinder 60 passes through a plunger 61 coupled to the movable iron core, and a valve body 62 is provided at the tip of the plunger 61 protruding into the valve chamber 55. The fuel container 64 has a mounting hole 65 at the center of the bottom wall, and the mounting cylinder 60 is inserted therethrough.
[0006]
Then, the valve main body 54 is fitted into the columnar body 51, the bottom wall of the fuel container 64 is overlaid on the lower end surface thereof, and the mounting cylinder 60 fitted with the gasket 66 is inserted into the mounting hole 65 from below and screwed into the valve main body 54. As a result, the valve body 54 is sandwiched and fixed between the columnar body 51 and the fuel container 64, and the gasket 66 is sandwiched between the fuel container 64 and the housing 59 so that the clearance between the mounting cylinder 60 and the mounting hole 65 is liquid. It is something that is dense. A float is enclosed in the fuel container 64 so as to surround the columnar body 51 and holds a certain amount of fuel.
[0007]
When the key switch of the engine is turned on, the actuator 58 is energized and sucks the plunger 61 and pulls the valve body 62 away from the valve seat 56, so that it is measured by the main jet 63 from the fuel container 64 and enters the valve chamber 55. The fuel passes through the valve seat 56 and flows into the fuel passage 52. When the key switch is turned off, the actuator 58 is de-energized and the valve body 62 is seated on the valve seat 56, thereby closing the lower end inlet of the fuel passage 52.
[0008]
[Problems to be solved by the invention]
The vaporizer was made entirely of metal in the old days, but it can be made of synthetic resin to meet the demands for weight reduction and workability of complex shapes. For example, the fuselage, columnar body and fuel container should be made of synthetic resin. (See Japanese Utility Model Publication No. 49-39710), and it has been proposed that the columnar body and the fuel container are made of synthetic resin (see US Pat. No. 5,049,318). Thus, a vaporizer made of at least a part of a synthetic resin has been put into practical use.
[0009]
However, the fuel container 64 is sandwiched between the valve main body 54 and the actuator 58 and is tightened with the gasket 66 compressed so that there is no fuel leakage. Is receiving.
[0010]
For this reason, when the fuel container 64 is made of synthetic resin in response to the above-described requirements, the tightening force and the load are applied without interruption, and further, the fuel container 64 is subjected to vibrations of the carburetor-equipped engine and equipment. There is a concern that creep may occur around the hole 65 and tightening may be loosened to cause fuel leakage and further damage to the fuel container 64.
[0011]
The present invention has been made to solve the above-mentioned problem that when the fuel container is made of synthetic resin, the fuel cutoff valve cannot be stably installed on the bottom wall of the fuel container. It is an object of the present invention to provide a reliable mounting structure in which a fuel shut-off valve can be installed without worrying about causing creep.
[0012]
[Means for Solving the Problems]
The fuel container provided under the fuselage having the intake passage is made of synthetic resin, and this fuel container has a columnar body provided with a fuel passage for sending fuel to the intake passage, and an inlet portion of the fuel passage. The actuator of the fuel cutoff valve that opens and closes is held on the bottom wall, and the actuator is a solenoid type that operates the valve body so that the inlet part is opened when the engine key switch is turned on and closed when it is turned off The above problem has been solved by attaching the fuel shut-off valve, in particular, the actuator to the fuel container as follows.
[0013]
In other words, a metal sleeve having a female threaded hole is fitted and installed on an annular projection formed on the bottom wall of the fuel container, and a gasket is provided at the lower end of the sleeve and the annular projection across the circumferential joint surface. Then, the externally threaded mounting cylinder projecting from the housing of the actuator is screwed into the female threaded hole, and the housing is held by the sleeve while the gasket is compressed.
[0014]
In this way, the metal sleeve is fitted and installed on the ring protrusion provided on the fuel container, and the actuator cylinder is screwed into the sleeve to hold the actuator of the fuel shut-off valve, which is a means for preventing the diesel phenomenon. According to the present invention, the mounting cylinder made of metal of the actuator is screwed and coupled to the sleeve which is also made of metal and has no fear of creep, so that the actuator can be stably held.
[0015]
In addition, a gasket is provided at the lower end of the sleeve and the ring projection across the circumferential joint surface, and the gasket is compressed by the actuator housing, so that a gap due to a difference in thermal expansion coefficient is created on the circumferential joint surface. Even if it occurs, the liquid tightness is maintained and the fuel does not leak, thereby achieving the object of obtaining a reliable mounting structure.
[0016]
Here, if the sleeve is provided with an annular ridge along the inner peripheral surface of the gasket and the end face of the housing is in contact with the end face of the annular ridge to limit the compression amount of the gasket, the mounting cylinder may There is an advantage that the reliability can be further improved without worrying that the gasket is damaged due to excessive compression due to screwing or that the fuel container is deformed by stress.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 show a first embodiment. The venturi 3 and the throttle valve 4 are mainly described with reference to FIG. A columnar body 5 is formed by integral molding so as to be positioned below the venturi 3 of the fuselage 1 provided sideways with the intake passage 2 provided with the side, and the columnar body 5 opens to the lower end surface and reaches a depth near the venturi 3. A hole 6 is provided. Also, a bowl-shaped fuel container 7, which is a molded product of a synthetic resin, preferably a synthetic resin called engineering plastic, is attached under the fuselage 1. The float 8 which works so as to maintain a constant fuel oil level is accommodated.
[0018]
In the hole 6 of the columnar body 5, a nozzle tube 9 made of a pipe having a flange-shaped receiving edge 10 and a locking edge 11 near the lower end and the upper end brings the locking edge 11 into contact with the back end surface of the hole 6. The receiving edge 10 is placed near the lower end of the hole 6. Further, the lower end portion of the hole 6 has a female screw, and the main jet 12 is screwed into the female screw and fixed to the columnar body 5, and the receiving edge 10 is overlapped on the front end surface of the main jet 12, thereby the nozzle tube. 9 is fixed in the above position.
[0019]
The receiving edge 10 and the locking edge 11 are made approximately the same diameter as the hole 6, and the nozzle tube 9 is inserted concentrically into the hole 6 and communicates with the jet hole of the main jet 12. Further, the nozzle tube 9 has a large number of bleed holes in a portion located in the lower end region of the hole 6, and this portion forms an emulsion tube 13 and penetrates the body 1 closely from the deep end of the hole 6. Thus, the portion protruding from the venturi 3 forms the main nozzle 14 having the nozzle port 15 at the tip. On the other hand, a bleed air passage 16 extending from the upstream side of the venturi 3 of the intake passage 2 is connected near the upper end, which is the back end of the hole 6, so that bleed air introduced into the hole 6 from the bleed hole passes through the nozzle tube 9. Get into the fuel.
[0020]
The nozzle tube 9 extending from the main jet 12 to the nozzle port 15 installed at the lower end of the columnar body 5 extends in the vertical direction inside the columnar body 5 and sends the fuel in the fuel container 7 to the intake passage 2. A main fuel passage is formed in the fuel passage 18, and a fuel reservoir 17 is formed in a substantially lower half portion of the hole 6, that is, a region extending from substantially the same position as the fuel oil surface of the fuel container 7 to the receiving edge 10. The low-speed fuel passage for sending fuel from the side of the throttle valve 4 to the intake passage 2 has a portion extending from the fuel reservoir 17 and extending in the vertical direction inside the columnar body 5 in parallel with the hole 6. Also, a part of the fuel passage 18 inside the columnar body 5 is formed.
[0021]
Referring to FIGS. 1 and 2, an annular ring projection 20 is formed on the bottom wall 19 of the fuel container 7 on the same center line as the main jet 12 and the nozzle tube 9 by integral molding. Projecting toward the inside. A cylindrical sleeve 22 has a female screw hole 24 in a portion extending from the lower end of the through hole 23 to the vicinity of the upper end, and a metal sleeve 21 having an annular protruding edge 25 on the outer peripheral surface of the upper end. The projecting edge 25 is fitted on the ring projection 20 so as to overlap the upper end surface. The sleeve 21 is fitted into the molded product of the fuel container 7 and fixed by high frequency welding, or is fitted and fixed simultaneously with the molding of the fuel container 7 by an insert molding method. The outer peripheral surface of 22 can be provided with a protrusion or rib that bites into the ring protrusion 20, or a retaining means that includes a recess that bites the synthetic resin of the ring protrusion 20.
[0022]
An annular groove 27 is formed at the lower end surface of the ring projection 20 and the cylindrical body 22 facing the lower side of the fuel container 7 so as to straddle the circumferential joining surface 26, and the gasket is formed of an elastic seal ring having a square or circular cross section. 29 is fitted in the annular groove 27. The wall of the annular groove 27 formed by the lower end portion of the cylindrical body 22 along the inner peripheral surface of the gasket 29 is formed by an annular protrusion 28 having a height slightly lower than the thickness of the gasket 29.
[0023]
Next, the fuel shut-off valve 31 serving as a means for preventing the diesel effect is electromagnetically driven, and a mounting cylinder 34 having a male screw 35 is mounted on a housing 33 of a well-known solenoid type actuator 32 including an electromagnet, a movable iron core, and a spring. A plunger 36 that protrudes and is coupled to the movable iron core passes through the mounting cylinder 34 and protrudes to the outside, and a valve body 37 is provided at the tip thereof. In the present embodiment, the valve seat 38 of the fuel cutoff valve 31 is formed by the lower end inlet portion of the main jet 12 in particular.
[0024]
The actuator 32 of the fuel shut-off valve 31 is inserted into the through hole 23 from below the fuel container 7 and the end face of the housing 33 compresses the gasket 29 to contact the annular protrusion 28. The mounting cylinder 34 is screwed into the female screw hole 24 until it is stopped, so that it is held by the sleeve 21 and attached to the fuel container 7. At this time, since the actuator 32 is in a non-excited state, the valve body 37 advanced by a spring is brought into close contact with the valve seat 38 and shuts off the inside of the fuel container 7 and the fuel passage 18.
[0025]
When the key switch of the engine is turned on, the actuator 32 is energized to suck the plunger 36 and pull the valve element 37 away from the valve seat 38, whereby the fuel in the fuel container 7 is measured by the main jet 12 and the fuel passage. 18 enters the intake passage 2. When the key switch is turned off, the actuator 32 is de-energized so that the valve element 37 is seated on the valve seat 38, so that diesel fuel is not generated due to continued fuel outflow.
[0026]
According to this embodiment, the mounting cylinder 34 of the housing 33 made of metal has a screwing depth over its entire height, and is screwed into the sleeve 21 which is also made of metal and does not cause creep. Since they are coupled, the actuator 32 can be held in a stable state without causing looseness. In addition, by setting the thickness of the ring protrusion 20 appropriately, it is possible to give sufficient strength to the portions that receive the weight of the actuator 32 and the sleeve 21, and to eliminate the risk of creep even if the load acts without interruption. .
[0027]
Further, even if a gap is generated in the circumferential joint surface 26 between the ring projection 20 and the sleeve 21 due to a difference in thermal expansion coefficient between the metal and the synthetic resin, a strain in the fuel container 7, or the like, the joint surface 26 is disposed across the joint surface 26. The formed gasket 29 can prevent fuel leakage and eliminate the risk of waste of fuel, surrounding contamination, and ignition, and can be used safely. In particular, in the present embodiment, the annular protrusion 28 of the sleeve 21 prevents the gasket 29 from being compressed more than a certain amount. Therefore, the mounting cylinder 34 is excessively screwed and the gasket 29 is excessively compressed and damaged. There is no need to worry about the disadvantage that a large stress acts on the ring projection 20 of the container 7 to cause deformation, and higher reliability can be provided.
[0028]
In addition, according to the present embodiment, the ring protrusion 20 is formed upward on the bottom wall 19 and the mounting cylinder 34 is screwed to the sleeve 21 inside the fuel container 7, so that the entire carburetor is conventionally used. Therefore, there is an advantage that it can be installed as it is in the installation space of the conventional vaporizer.
[0029]
FIG. 3 shows a second embodiment of the present invention, and an annular ring protrusion 40 is formed on the bottom wall 19 of the fuel container 7 so as to protrude downward from the fuel container 7 by integral molding. The same sleeve 21 as in the first embodiment is fitted with the protruding edge 25 overlapped on the upper surface of the bottom wall 19. The annular protrusion 40 and the sleeve 21 have their lower end surfaces aligned on substantially the same plane, and a gasket 29 is fitted and mounted in an annular groove 42 formed across the circumferential joining surface 41. The sleeve 21 is fitted and fixed to the ring projection 40 by the same means as described in the first embodiment.
[0030]
The actuator 32 of the fuel shut-off valve 31 is held on the sleeve 21 by screwing the mounting cylinder 34 into the female screw hole 24 of the sleeve 21 until the end face of the housing 33 compresses the gasket 29 and contacts the ring ridge 28. It is attached to the container 7.
[0031]
The fuel cutoff valve 31 in the present embodiment includes a valve body 43 similar to the valve body 54 shown in the conventional example. The valve body 43 has a valve chamber 44 inside, a valve seat 45 provided at the top, and a main jet 46 attached to the peripheral side wall of the valve chamber 44. The valve main body 43 is fitted in a liquid-tight manner using an O-ring 47 at the upper end of the lower end of the hole 6 of the columnar body 5, and the lower end surface is overlaid on the upper end surface of the sleeve 21. It is installed inside the fuel container 7 in a sandwiched and fixed state. Further, the nozzle pipe 9 of the fuel passage 18 is installed in the hole 6 when the receiving edge 10 at the lower end overlaps with the valve body 43.
[0032]
The plunger 36 protruding from the mounting cylinder 34 extends upward in the valve chamber 44, and the valve body 37 provided at the tip of the plunger 36 is seated on the valve seat 45 when the engine key switch is turned off. When the inside of the fuel container 7 and the fuel passage 18 are shut off and turned on, the fuel is separated from the valve seat 45 and the fuel in the fuel container 7 is sucked through the main jet 46, the valve chamber 45, the valve seat 45, and the fuel passage 18. It is sent to the passage.
[0033]
Also in this embodiment, the actuator 32 is held in the fuel container 7 in a stable state, the synthetic resin fuel container 7 is not creeped, fuel is not leaked, and the gasket 29 is not excessively compressed. The same effect as that of the one embodiment can be obtained.
[0034]
In the present embodiment, the ring protrusion 40 is formed downward on the bottom wall 19 and the mounting cylinder 34 is screwed to the sleeve 21 below the fuel container 7, so that the total height of the carburetor is the first embodiment. There is an inconvenience that the height of the ring projection 40 is higher than that of the form and a large installation space is required, but the fuel container 7 itself has the same height as the conventional one, and the valve body 43 with the main jet 46 is incorporated. There is an advantage that it can be installed.
[0035]
【The invention's effect】
As described above, according to the present invention, the metal housing of the actuator of the fuel cutoff valve can be stably held in the synthetic resin fuel container without fear of causing creep or fuel leakage.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a first embodiment of the present invention.
FIG. 2 is an enlarged vertical sectional partial view of FIG.
FIG. 3 is a partial longitudinal sectional view showing a second embodiment of the present invention.
FIG. 4 is a partial longitudinal sectional view showing a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Body, 2 Air intake passage, 5 Columnar body, 7 Fuel container, 18 Fuel passage, 19 Bottom wall, 20, 40 Ring protrusion, 21 Sleeve, 24 Female screw hole, 26, 41 Circumferential joining surface, 28 Ring protrusion, 29 Gasket, 31 Fuel shutoff valve, 32 Actuator, 33 Housing, 34 Mounting cylinder, 35 Male thread, 37 Valve body,

Claims (1)

A fuel container provided under the fuselage having an intake passage is made of a synthetic resin, and the fuel container has a columnar body provided with a fuel passage for sending fuel to the intake passage and an inlet portion of the fuel passage. A solenoid-type valve that operates the valve body so that the inlet portion is opened when the key switch of the engine is turned on and closed when the key switch of the engine is turned off. der is, together with a metal sleeve having an internal thread hole is placed fitted to form the ring projections at the bottom wall of the fuel container, which spans the circumferential direction junction surface between the sleeve and the ring projection A gasket is provided at the lower end of the housing, and the actuator is screwed into the female threaded hole with a male threaded mounting cylinder projecting from the housing; and Ujingu is in the fuel cutoff valve mounting structure of the carburetor, which is held in the sleeve while compressing the gasket has a ring ridge the sleeve along the inner circumferential surface of the gasket, of the housing A fuel cutoff valve device for a carburetor, characterized in that an end surface is in contact with an end surface of the ring projection to limit the compression amount of the gasket .

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