JPH0238057Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention is a variable bench lily type vaporizer equipped with a tapered metering needle inserted into the main jet and controlling the opening area at the tip of the sliding valve. Concerning vessels.

[Prior art]

In this type of carburetor, due to dimensional tolerances and assembly tolerances of each part, errors occur in the longitudinal positional relationship between the metering needle attached to the tip of the sliding valve and the main jet attached to the carburetor body. Therefore, since the opening area of the main jet varies for each product, there is a problem that the fuel flow rate varies. In order to solve this problem, conventionally, as exemplified in Japanese Unexamined Patent Publication No. 10142/1983,
The main nozzle with the main jet is adjustable in its longitudinal position with respect to the carburetor body, and this adjustment eliminates variations in the opening area of the main jet due to the above-mentioned tolerances.

[Problem that the invention attempts to solve]

However, in such conventional technology, the opening area of the main jet is adjusted by moving the main nozzle in the longitudinal direction, so the positional relationship of the main jet with respect to the intake passage and other parts on the carburetor body side changes during adjustment. However, this poses a problem in that it becomes a new cause of variations in performance at positions other than the adjustment points. Additionally, even a small amount of fuel leaking from the sliding fitting surfaces during adjustment will cause an error in the fuel flow rate, so in order to eliminate such fuel leakage, each fitting surface is precisely machined to ensure a reliable seal. Therefore, there was a problem that processing costs increased.

On the other hand, in the technique disclosed in Japanese Patent Application Laid-open No. 56-14846, the above problem is solved by moving the jet needle (metering needle) in the axial direction relative to the slide valve to perform adjustment. ing. However, in this technique, one side of the head member that is fixed to the jet needle and pushed up by a spring is pushed down by an adjustment screw, so when moving due to adjustment, the jet needle is twisted and becomes unable to move. This causes a problem of poor adjustment reproducibility.

The present invention solves the above-mentioned problems by moving the metering needle relative to the slide valve using an adjusting screw via a needle guide fitted into the slide valve.

[Means for solving problems]

For this purpose, the variable bench lily type carburetor according to the present invention has an intake passage 11 as illustrated in the attached drawings.
and a bench lily that is slidably fitted into the carburetor body in a direction intersecting the intake passage 11 and has an opening area that changes between the bottom 21 of the carburetor body 10 and a part of the inner surface of the intake passage. A bottomed cylindrical sliding valve 20 forming the bottomed part 13, a main nozzle 17 provided on the carburetor main body 10 coaxially with the sliding valve, and a main nozzle 17 provided on the carburetor body 10 coaxially with the sliding valve 20 from the bottom part 21. A variable bench lily type carburetor comprising a tapered metering needle 30 which is protruded from the main nozzle 17 and inserted into the main jet 17a of the main nozzle 17 to control the opening area of the main jet by sliding the sliding valve. A needle guide hole 22 that opens inward is coaxially formed in the bottom 21 of the sliding valve 20, and the metering needle 30 has a needle flange 31 integrally provided at its base end. The needle guide hole 2
2 and protrudes axially from the bottom 21 of the slide valve 20 through the bottom wall 23 of the needle guide hole, and further advances and retreats into the slide valve 20 from a direction substantially perpendicular to the sliding direction. a tapered portion 35 that can be screwed together and protrudes into the needle guide hole 22 at a position more inward than the needle flange 31;
an adjusting screw 35 having a tip a, and a projection that is slidably fitted into the needle guide hole 22 between the needle flange 31 and the tapered part 35a and can come into contact with the tapered part 35a at the center of the upper surface. 32a, and is interposed between the bottom wall 23 of the needle guide hole 22 and the needle flange 31, so that the needle flange comes into contact with the tapered part 35a via the needle guide 32. It is characterized by being equipped with a needle spring 33.

[Effect]

When the slide valve 20 is set at a predetermined position and the adjusting screw 35 is rotated in the forward direction, the needle guide 32 fitted in the needle guide hole 22
is pushed and moved via the protrusion 32a by the tapered portion 35a which advances together with the adjuster screw 35. This movement pushes the needle flange 31 and moves the metering needle 30 forward against the needle spring 33 in the direction of protruding from the bottom 21 of the slide valve 20. As a result, the larger diameter portion of the tapered metaling needle 30 is inserted into the main jet 17a, so that the opening area of the main jet 17a is adjusted in the direction of decreasing.
Fuel flow decreases. If the adjusting screw 35 is rotated in the backward direction in the opposite direction to the above, the metering needle 30 is moved backward into the bottom portion 21 of the slide valve 20 by the needle spring 33. As a result, the diameter of the portion of the metering needle 30 inserted into the main jet 17a becomes smaller, so that the opening area of the main jet 17a is adjusted to increase, and the fuel flow rate increases. During adjustment, the component force in the direction perpendicular to the axis of the force generated at the contact portion between the tapered portion 35a of the adjuster screw 35 and the protrusion 32a of the needle guide 32 is caused by the surface contact between the needle guide hole 22 and the needle guide 32. It is received and only axial force is applied to the metering needle 30. Therefore, the metaling needle 30 is not twisted and moves smoothly.

[Effect of idea]

As described above, according to the present invention, when adjusting the opening area of the main jet, the positional relationship of the main jet with respect to the intake passage and other parts on the carburetor body side does not change, so the adjustment does not change the state of fuel flow. There is no variation in performance at positions other than the adjustment point. Furthermore, since the metering needle 30 is not twisted during adjustment, its movement becomes smooth and the reproducibility of adjustment is greatly improved. Furthermore, since the part that moves during adjustment is located in the air circulation area where the flow rate is much larger than that of fuel, even if there is a slight gap, it will have little effect on the air-fuel ratio, and therefore the machining accuracy of the adjustment part can be improved. There is no need to increase the manufacturing cost, and the manufacturing cost can be reduced.

〔Example〕

First, the first embodiment shown in FIG. 1 will be explained.

The carburetor main body 10 is formed with an intake passage 11 and a guide hole 10a perpendicular to the intake passage 11, and a bottom 21 at the tip of a bottomed cylindrical slide valve 20 that is guided and supported in the guide hole 10a so as to be able to slide only in the axial direction. A bridge portion 11a at the center of the intake passage 11 forms a bench lily portion 13. A cover 14 that covers the open end side of the slide valve 20 is fixed to the carburetor body 10, and a diaphragm 26 made of an elastic material such as rubber, whose outer periphery is clamped and fixed between the cover 14 and the carburetor body 10.
The inner peripheral edge of is fixed to the opening edge of the sliding valve 20,
The space formed between the cover 14 and the carburetor body 10 is connected to an atmospheric pressure chamber 18 communicating with the upstream side of the sliding valve 20 of the intake passage 11 and a negative pressure chamber communicating with the downstream side of the bench lily portion 13. It is separated into 19.
The slide valve 20 is biased toward the bridge portion 11a by a spring 27 installed between the slide valve 20 and the cover 14, and as a result, as shown in FIG. Valve 1
2 is closed and the amount of intake air is small, the sliding valve 20 is closest to the bridge portion 11a and the opening area of the bench lily portion 13 is minimized. As the opening degree of the throttle valve 12 increases and the amount of intake air increases, the negative pressure in the negative pressure chamber 19 gradually increases, so that the slide valve 20 rises against the spring 27, causing the bench lily portion 13 to rise. The opening area is gradually increased.

As shown in FIG. 1, a needle guide hole 22 opening inward of the slide valve 20 is formed coaxially with the slide valve 20 in the bottom portion 21, and a metering needle is inserted into the needle guide hole 22. A needle flange 31 integrally caulked and fixed to the base end of the metal ring 30 is located, and the metal ring 30 has a tapered shape.
penetrates the bottom wall 23 of the needle guide hole 22 and protrudes axially downward from the bottom 21 thereof, substantially coaxially with the slide valve 20. A needle guide 32 having a protrusion 32a at the center of the upper surface is slidably inserted into the needle guide hole 22, located above the needle flange 31. Needle guide hole 22
A needle spring 33 is interposed between the bottom wall 23 and the needle flange 31, and the needle flange 31 is elastically brought into contact with a tapered portion 35a at the tip of an adjusting screw 35, which will be described later, via a needle guide 32. are in contact with each other.

A main nozzle 17 is fixed to the carburetor body 10 coaxially with a slide valve 20, and a metering needle 30 is inserted into a main jet 17a formed at the upper part of the main nozzle 17. The lower part of the main nozzle 17 is located within a float bowl 15 fixed to the carburetor body 10. In this embodiment, the upper surface of the bottom wall 23 against which the needle spring 33 comes into contact is inclined, and a protrusion is provided at the upper center of the needle flange 31, so that the metering needle 30 is moved in the W direction in FIG. It is inclined and elastically biased so as to lightly contact the downstream side of the main jet 17a.

An adjusting screw 35 is attached to the sliding valve 20 from the upstream side of the intake passage 11 perpendicularly to the sliding direction thereof.
are screwed together so that they can move forward and backward. A tapered portion 35a formed at the tip of the adjusting screw 35 projects into the needle guide hole 22 at a position inward of the needle flange 31 and the needle guide 32, and the needle spring 33 uses its urging force to The hemispherical protrusion 32a at the center of the upper surface of the guide 32 abuts against the tapered portion 35a to position the metering needle 30 in the axial direction via the needle flange 31. The head 35b of the adjusting screw 35 is located within the recess 24 formed in the slide valve 20, and a back spring 36 is interposed between the head 35b and the bottom surface of the recess 24. This provides resistance to the free rotation of the The head 35b does not protrude from the recess 24 in the entire adjustment range of the adjuster screw 35.

Adjustment of the variation in the opening area of the main jet 17a is performed with the sliding valve 20 closest to the bridge portion 11a as shown in FIG. 1, that is, with the opening area of the main jet 17a being at its minimum. In this state, insert the adjusting tool into the head 35b of the adjusting screw 35 from the upstream side of the intake passage 11.
When the needle flange 31 is rotated in the forward direction Y, the needle flange 31 is pushed downward via the needle guide 32 having a protrusion 32a that comes into contact with the tapered portion 35a that moves forward together with the adjusting screw 35, and the metering needle 30 is advanced against the needle spring 33 in the direction Q to protrude from the bottom 21 of the slide valve 20. As a result, the larger diameter portion on the root side of the tapered metaling needle 30 is inserted into the main jet 17a, so that the main jet 1
The opening area of 7a is adjusted to decrease. When the adjuster screw 35 is rotated in the retraction direction X, the metering needle 30 is retracted in the direction P into the bottom portion 21 of the slide valve 20 by the biasing force of the needle spring 33 due to the opposite effect to that described above.
As a result, the smaller diameter portion on the distal end side of the metering needle 30 is located within the main jet 17a, so that the opening area of the main jet 17a is adjusted to increase. During adjustment, the tapered portion 35a of the adjuster screw 35 is connected to the protrusion 3.
2a in an oblique direction, and as a result, the needle guide 32 receives a component force in a direction perpendicular to the axis, but this component force is received by the fitting surface between the needle guide hole 22 and the needle guide 32, and the metal ring It is not transmitted to needle 30. Therefore, since only the force in the axial direction is applied to the metering needle 30, no twisting occurs.
The main jet 17a moves smoothly.
The reproducibility of adjusting the aperture area is greatly improved.

In the second embodiment shown in FIGS. 2 and 3, the lower surface of the needle guide 32 that contacts the needle flange 31 is an inclined surface, and the needle flange 31
Needle spring 3 except for the protrusion at the center of the top surface
3, one side of the upper surface of the needle flange 31 comes into contact with the inclined surface, and the metering needle 30 is elastically urged in the W direction. In this embodiment, the needle guide 32 has a protrusion 32a.
The needle guide hole 22 is provided with a guide groove 22a that engages with the protrusion 32a.
This prevents rotation of 2. Since the other configurations are the same as those in the first embodiment, corresponding parts are simply given the same reference numerals and detailed explanations are omitted.

In the third embodiment shown in FIG. 4, the lengths of the needle guide hole 22 and the needle guide 32 are increased so that adjustment of the adjuster screw 35 is performed through an adjustment hole 37 provided independently of the intake passage 11. This is what I did. According to this embodiment, the flow within the intake passage 11 is not disturbed during adjustment, so the accuracy of adjustment can be improved. After adjustment, the adjustment hole 37 may be closed with a plug 38 or the like, if necessary. In addition, adjustment hole 3
7 need not be provided parallel to the intake passage 11 as in this embodiment, but may be provided perpendicularly to the intake passage 11 or intersecting it at an arbitrary angle. In this embodiment, the weight of the needle guide 32 is large and it is likely to resonate due to engine vibration, etc., but in order to prevent this, a spring 34 is used to bring only the needle guide 32 into contact with the tapered portion 35a of the adjuster screw 35. has been established. Other configurations are the first
Since this is the same as the embodiment, corresponding parts will only be denoted by the same reference numerals, and detailed explanation will be omitted.

Note that in the first and second embodiments as well, it is effective to provide a spring corresponding to the spring 34 depending on the situation. Further, in each of the above embodiments, the adjuster screw 35 is connected to the slide valve 20.
Although they are screwed together perpendicularly to the sliding direction, they may be screwed onto the slide valve 20 from a slightly upward or downward direction.

[Brief explanation of the drawing]

FIG. 1 is an overall vertical sectional view of a first embodiment of a variable bench lily type carburetor according to the present invention, FIG. 2 is a sectional view of a modified part of the second embodiment, and FIG. 3 is a -
The cross-sectional view, FIG. 4, is an overall vertical cross-sectional view of the third embodiment. Explanation of symbols, 10... Carburetor body, 11... Intake passage, 13... Bench lily part, 17... Main nozzle, 17a... Main jet, 20... Sliding valve, 21... Bottom, 22... Needle Guide hole, 23...Bottom wall, 30...Metering needle, 31...Needle flange, 32...Needle guide, 32a...Protrusion, 33...Needle spring, 35...Adjustment screw, 35a... …
Tapered part.

Claims (1)

[Scope of utility model registration request] A carburetor body having an intake passage, and a bench lily part that is slidably fitted into the carburetor body in a direction intersecting the intake passage and has an opening area that changes between the bottom of the carburetor body and a part of the inner surface of the intake passage. a bottomed cylindrical slide valve forming a bottom, a main nozzle provided on the carburetor main body coaxially with the slide valve, and a main nozzle attached to the slide valve so as to protrude substantially coaxially from the bottom thereof. In a variable bench lily type carburetor, the carburetor is equipped with a tapered metering needle that is inserted into the main jet of the valve and controls the opening area of the main jet by sliding the sliding valve. A needle guide hole is formed coaxially with the metering needle, and a needle flange integrally provided at the proximal end of the metering needle is located within the needle guide hole, and a bottom wall of the needle guide hole is located within the needle guide hole. The needle protrudes in the axial direction from the bottom of the sliding valve, and is further screwed into the sliding valve so that it can move forward and backward in a direction substantially perpendicular to the sliding direction, and is located inward from the needle flange. An adjusting screw having a tapered portion at its tip that projects into the guide hole, and an adjusting screw that is slidably fitted into the needle guide hole between the needle flange portion and the tapered portion, and can come into contact with the tapered portion at the center of the upper surface. a needle guide having a protrusion, and a needle spring interposed between the bottom wall of the needle guide hole and the needle flange to bring the needle flange into contact with the tapered part via the needle guide. A variable bench lily type vaporizer characterized by: