JP3703513B2 - Carburetor - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a carburetor capable of exchanging a main jet and a pilot jet.
[0002]
[Prior art]
As shown in FIG. 5, in a carburetor including a slow system (pilot system) that forms an air-fuel mixture in the range from engine idling to low speed operation and a main system that forms an air-fuel mixture in the range from low speed operation to high speed operation. A main main jet 108 and a slow pilot jet 109 are provided.
[0003]
[Problems to be solved by the invention]
In the above case, in the conventional carburetor 101 shown in FIG. 5, the main jet 108 can be easily removed by removing the drain bolt 111 and replaced with another one.
[0004]
However, the diameter of the conventional drain bolt 111 is small, and therefore, even if the drain bolt 111 is removed, the pilot jet 109 remains in the opening at the bottom of the float chamber 107 (opening opened by removing the drain bolt 111) 107a. The pilot jet 109 is not exposed and cannot be seen hidden behind the partition wall 112 for preventing the oil surface from undulating. Therefore, the pilot jet 109 is removed just like the main jet 108 by removing the drain bolt 111. It was not possible to exchange for the one, and the degree of freedom of setting was narrow.
[0005]
Therefore, conventionally, the pilot jet 109 cannot be exchanged unless the troublesome work of removing the float chamber 109 from the main body of the carburetor 101 after removing the entire carburetor 101 from the vehicle body is difficult, and the work is very time-consuming. There was a problem of requiring.
[0006]
In particular, in a rainy race of a motocrosser that runs on a wasteland, if the carburetor is removed for setting the carburetor or the float chamber is removed, mud and dust adhere to the parts, causing trouble.
[0007]
The present invention has been made in view of the above problems, and the purpose of the present invention is that the main jet and the pilot jet can be easily replaced by simply removing the drain bolt, and the setting flexibility can be expanded. An object of the present invention is to provide a carburetor capable of improving work efficiency and preventing troubles caused by foreign matter adhering or mixing during setting.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a mixing chamber having a venturi portion ,
A float chamber attached to the bottom of the mixing chamber;
A main jet and a pilot jet that face the float chamber and are detachably attached to the mixing chamber ;
A cup-shaped drain bolt that is screwed into an opening formed in the float chamber bottom,
In a carburetor comprising
The main jet and the pilot jet are arranged so as to be included in an opening formed at the bottom of the float chamber on a horizontal projection plane, and the main jet and the pilot jet are made detachable through the opening,
The upper end portion of the drain bolt extended to the float chamber, to form a circular hole at its extended portion, enclose the periphery of the main jet at the extending portion,
A partition wall surrounding the main jet and the pilot jet is disposed in the float chamber, the partition wall defines the inside of the float chamber into two chambers, and is formed between the partition wall and the extended portion of the drain bolt. The two chambers are communicated with each other through the formed clearance and the circular hole formed in the extended portion of the drain bolt .
[0009]
[Action]
According to the present invention, if the drain bolt is removed when setting the carburetor, a large opening is opened at the bottom of the float chamber, and the main jet and the pilot jet are exposed in the large opening. Can be removed and replaced with different ones to increase the degree of freedom in setting the carburetor, improve the efficiency of setting work, and adhere to and mix foreign matter on the carburetor when setting the carburetor It is possible to prevent troubles from occurring.
[0010]
【Example】
Embodiments of the present invention will be described below with reference to the accompanying drawings.
[0011]
<Example 1>
1 is a longitudinal sectional view of a carburetor according to Embodiment 1 of the present invention, and FIG. 2 is a view of the inside of the carburetor as viewed from below with a drain bolt removed.
[0012]
The carburetor 1 according to the present embodiment is a so-called VM carburetor, which has a mixing chamber 2, in which a venturi portion 2 a penetrating in the horizontal direction is formed, and the air is the venturi portion 2 a. Flows in the direction of the arrow in the figure. A piston-type throttle valve 3 is slidably fitted in a cylinder portion 2b formed integrally with the upper portion of the mixing chamber 2. The lower end of the throttle valve 3 tapers downward. The jet needle 4 is attached. The throttle valve 3 is always urged downward (throttle side) by a spring 5, and the throttle valve 3 is connected to an accelerator (not shown) via a throttle wire 6.
[0013]
On the other hand, a float chamber 7 is attached to the lower part of the mixing chamber 2, and fuel is accommodated in the float chamber 7. Also, in the float chamber 7, a main jet 8 and a pilot jet 9 that are detachably screwed to the mixing chamber 2 from the bottom face.
[0014]
The main jet 8 constitutes a main system, which measures the supplied fuel in the range of low speed operation to high speed operation of the engine, and the inside of the jet needle 4 inserted through the main nozzle 10 ( The lower end is facing. The pilot jet 9 constitutes a slow system (pilot system), which measures the supplied fuel in a range from engine idling to low speed operation.
[0015]
By the way, an opening 7a, which is a large-diameter screw hole, is formed at the bottom of the float chamber 7, and the opening 7a is closed by a cup-shaped drain bolt 11 screwed thereto.
[0016]
Thus, in this embodiment, as shown in FIG. 2, the main jet 8 and the pilot jet 9 are configured to be included in an opening 7a formed at the bottom of the float chamber 7 on the horizontal projection plane. ing. This is realized by making the opening 7a of the float chamber 7 larger than the conventional opening 107a (see FIG. 5).
[0017]
Further, a partition wall 12 is stored in the front chamber 7 for suppressing the undulation of the oil level of the fuel. As shown in FIG. 2, the partition wall 12 is formed of a resin into a square cylinder shape, and the main jet 8 and the pilot jet 9 are surrounded by the partition wall 12. The chambers S1 and S2 defined by the partition wall 12 in the float chamber 7 have a plurality of circular holes 11a formed in the side wall of the drain bolt 11 and a gap δ between the partition wall 12 and the drain bolt 11. The fuel is supplied to the main jet 8 and the pilot jet 9 through the circular holes 11a and the gap δ, respectively.
[0018]
Thus, in a motorcycle or the like provided with the carburetor 1, the carburetor 1 is set by exchanging the main jet 8 and the pilot jet 9 for different ones. The setting of 1 is made as follows.
[0019]
That is, when setting the carburetor 1, first, the drain bolt 11 is removed from the float chamber 7. Then, a large opening 7a opens at the bottom of the float chamber 7. As described above, the main jet 8 and the pilot jet 9 are included in the opening 7a on the horizontal projection plane, and the partition wall 12 is connected to the main jet 8 and the pilot. Since the lower part of the jet 9 is not covered, the main jet 8 and the pilot jet 9 are exposed in the large opening 7a.
[0020]
Accordingly, the operator can see the internal main jet 8 and the pilot jet 9 from below through the opening 7a, insert a tool (not shown) from the opening 7a, rotate the main jet 8 and the pilot jet 9, and The pilot jet 9 can be easily removed and taken out from the opening 7a, and these can be replaced with different ones. After the main jet 8 and the pilot jet 9 are exchanged in this manner, the drain bolt 11 is screwed into the opening 7a to close the opening 7a, and the setting of the carburetor 1 is completed.
[0021]
Thus, according to the present embodiment, when the carburetor 1 is set, the main jet 8 and the pilot jet 9 can be easily removed by simply removing the drain bolt 11, and these can be replaced with different ones. 1 degree of freedom of setting expands.
[0022]
In addition, since it is not necessary to remove the entire carburetor 1 from the vehicle body or to remove the float chamber 7 from the removed carburetor 1 as in the prior art, the setting work of the carburetor 1 is facilitated and the work efficiency is dramatically improved. In addition to being increased, it is possible to prevent foreign matter from adhering to and mixing into the parts of the carburetor 1 at the time of setting, thereby preventing various troubles.
[0023]
< Reference example >
Next, a reference example of the present invention will be described with reference to FIGS. FIG. 3 is a longitudinal sectional view of a carburetor according to a reference example of the present invention, and FIG. 3 is a view of the inside of the carburetor with the drain bolt removed, and these figures are shown in FIGS. The same elements as those shown are denoted by the same reference numerals, and description thereof will be omitted below.
[0024]
In this reference example , the shape of the partition wall 12 is substantially cylindrical, and its lower end is expanded in an elliptical shape so as to cover the upper end portion of the drain bolt 11 as shown in FIG. The chambers S1 and S2 in the float chamber 7 defined by the partition wall 12 communicate with each other by a plurality of circular holes 12a formed in the partition wall 12, and the fuel passes through the circular hole 12a and the main jet 8 And the pilot jet 9 respectively.
[0025]
Thus, also in the present reference example , as in the first embodiment, the main jet 8 and the pilot jet 9 are configured to be included in the opening 7a formed at the bottom of the float chamber 7 on the horizontal projection plane. Therefore, when the drain bolt 11 is removed from the float chamber 7 when setting the carburetor 1, a large opening 7 a is opened at the bottom of the float chamber 7, and the partition wall 12 does not cover the main jet 8 and the pilot jet 9. . Therefore, the main jet 8 and the pilot jet 9 by simply removing the drain bolt 11 can be easily replaced, the same effect as the first embodiment can be obtained by the present embodiment.
In the above-described embodiments and reference examples , the VM carburetor is particularly mentioned. However, the present invention also includes the SU carburetor as its application target.
[0026]
In the above embodiment, the VM carburetor is particularly mentioned. However, the present invention also includes the SU carburetor as its application target.
[0027]
【The invention's effect】
As is clear from the above description, according to the present invention, a mixing chamber having a venturi portion, a float chamber attached to a lower portion of the mixing chamber,
Faces into the float chamber, and provided with a main jet and pilot jet which is removably attached to the mixing chamber, and a cup-shaped drain bolt that is screwed into an opening formed in the float chamber bottom carburetor The main jet and the pilot jet are arranged so as to be included in an opening formed at the bottom of the float chamber on a horizontal projection plane so that the main jet and the pilot jet can be attached and detached through the opening, and the drain bolt extend the upper portion to the float chamber, to form a circular hole at its extended portion, enclose the periphery of the main jet at the extending portion, the float chamber a partition wall surrounding the main jet and pilot jet Arranged in the The wall defines the inside of the float chamber into two chambers, and a gap formed between the partition wall and the extended portion of the drain bolt and the circular hole formed in the extended portion of the drain bolt. The two chambers communicated with each other, so the main jet and pilot jet can be easily replaced by simply removing the drain bolt, increasing the degree of freedom in setting the carburetor, and improving the setting work efficiency. An effect is obtained that it is possible to prevent the occurrence of troubles due to adhesion or mixing of foreign matters to the carburetor during setting.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a carburetor according to Embodiment 1 of the present invention.
FIG. 2 is a view of the inside of the carburetor according to the first embodiment of the present invention as viewed from below with the drain bolt removed.
FIG. 3 is a longitudinal sectional view of a carburetor according to a reference example of the present invention.
FIG. 4 is a view of the inside of a carburetor according to a reference example of the present invention when viewed from below with the drain bolt removed.
FIG. 5 is a longitudinal sectional view of a main part of a conventional carburetor.
[Explanation of symbols]
1 Carburetor 2 Mixing chamber 2a Venturi 7 Float chamber 7a Opening 8 Main jet 9 Pilot jet 11 Drain bolt

Claims (1)

A mixing chamber having a venturi ;
A float chamber attached to the bottom of the mixing chamber;
A main jet and a pilot jet that face the float chamber and are detachably attached to the mixing chamber ;
A cup-shaped drain bolt that is screwed into an opening formed in the float chamber bottom,
In a carburetor comprising
The main jet and the pilot jet are arranged so as to be included in an opening formed at the bottom of the float chamber on a horizontal projection plane, and the main jet and the pilot jet are made detachable through the opening,
The upper end portion of the drain bolt extended to the float chamber, to form a circular hole at its extended portion, enclose the periphery of the main jet at the extending portion,
A partition wall surrounding the main jet and the pilot jet is disposed in the float chamber, the partition wall defines the inside of the float chamber into two chambers, and is formed between the partition wall and the extended portion of the drain bolt. A carburetor characterized in that the two chambers are communicated with each other through the formed gap and the circular hole formed in the extended portion of the drain bolt .

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