JPS628628B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a constant vacuum carburetor equipped with a negative pressure operated valve that moves up and down in the intake passage by the negative pressure generated in the intake passage upstream of the throttle valve, and particularly relates to a constant vacuum carburetor. A negative pressure operating valve is formed by a ventilee forming part and a plate-shaped guide part protruding from a side surface along the longitudinal axis of the ventilizing part, and the negative pressure operating valve is slidably guided to the carburetor main body. The present invention relates to a method for manufacturing a constant vacuum vaporizer.

Generally, in order to guide and hold the negative pressure operated valve of a constant vacuum type vaporizer in a slidable manner in the vaporizer main body, a guide groove is bored from the atmospheric chamber opening on the side of the vaporizer main body, and a guide groove is drilled into the guide groove. This is a device in which a negative pressure operated valve is arranged, and since the guide groove of the generally used cylindrical negative pressure operated valve is also cylindrical, it can be easily manufactured by drilling. . However, the present applicant has proposed a constant vacuum type carburetor with good air-fuel mixture controllability and excellent suction efficiency, that is, a negative pressure operated valve with a plate-shaped guide part protruding from the side of the ventilate forming part. In the case where the guide part is slidably arranged in a plate-shaped guide groove bored in the carburetor body, a part of the guide groove in the carburetor body is a plate-shaped part, and the thickness of the plate-shaped part is small. Because it is relatively thin (for example, 3 mm to 5 mm), drilling work cannot be used to process the plate-shaped guide groove, and casting work cannot be performed when forming the carburetor body, making it difficult and expensive to manufacture. .

The present invention has been made in view of the above-mentioned disadvantages, and is an extremely improved negative pressure operated valve for a constant vacuum type vaporizer, which has a negative pressure operated valve provided with a plate-shaped guide part protruding from the side of the ventilium forming part. The present invention relates to a method for manufacturing a constant vacuum type vaporizer that can be simply and reliably slidably guided and held in the vaporizer main body.

Hereinafter, one embodiment of the method for manufacturing a constant vacuum type vaporizer according to the present invention will be described with reference to the drawings. Figures 1 and 2
Figures 1 and 3 show the material of the carburetor main body. Figure 1 is a longitudinal cross-sectional view, Figure 2 is a top plan view of Figure 1, and Figure 3 is a longitudinal cross-section along the line shown in Figure 1. It is a diagram.

Reference numeral 1 denotes a carburetor body through which an intake passage 2 passes, an atmospheric chamber recess 3 on one side of the intake passage 2, and a main fuel boss 4 and a float chamber recess 5 on the other side of the intake passage 2. , a guide groove 6 is bored from the upper opening of the atmospheric chamber recess 3 . This guide groove 6 is connected to a negative pressure operated valve 1 which will be described later.
A ventilator forming part guide groove 7D for guiding the cylindrical ventilee forming part 17A of No. 7 and a plate-shaped guide groove 7E for guiding the plate-shaped guide part 17B.
It is formed so that a guide member 7 having a structure can be fitted therein.

The guide groove 6 in this embodiment consists of a central cylindrical groove 6A and a plate-shaped groove 6B extending laterally from the central cylindrical groove 6A.
The central cylindrical groove 6A opens into the intake passage 2 from the upper opening of the atmospheric chamber recess 3, while the plate-shaped groove 6B extends from the upper opening of the atmospheric chamber recess 3 to approximately the bottom of the intake passage 2.

Next, the guide member 7 disposed in the guide groove 6 will be explained with reference to FIGS. 4, 5, 6, and 7. 4 is a longitudinal sectional side view thereof, FIG. 5 is a top plan view of FIG. 4, FIG. 6 is a longitudinal sectional side view taken along the - line of FIG. 5, and FIG. 7 is a perspective view.

The guide member 7 has the same shape as the guide groove 6 drilled in the carburetor body 1 so as to be fitted into the guide groove 6 of the carburetor body 1, and has a cylindrical central tube at the upper center thereof. It has a portion 7A, plate-like portions 7B on both sides of the central cylinder portion 7A and below, and a through hole 7C that matches the intake path 2.

The guide member 7 also has a ventilate forming part guide groove 7D for guiding the cylindrical ventilium forming part 17A of the negative pressure operating valve 17 and a plate-shaped guide groove 7E for guiding the plate-shaped guide part 17B. It is formed.

In order to slide and hold the negative pressure operated valve 17 in the carburetor body 1 and the guide member 7 formed as described above, the guide groove 6 of the carburetor body 1 is formed as shown in FIG.
The guide member 7 is fitted and arranged therein.

According to this, the guide member 7 forms a ventilary forming part guide groove 7A and a plate-shaped guide groove 7B for slidingly guiding the negative pressure operated valve 17 inside the carburetor main body 1, and furthermore, a through hole 7C. It can be matched with the intake passage 2.

In addition, in order to accurately match the ventilary forming part guide groove 7A with the ventilary forming part 17A of the negative pressure operating valve 17, and to make the through hole 7C of the guide member 7 exactly match the intake path 2 of the carburetor main body 1. ,
After the guide member 7 is fitted into the carburetor main body 1, it may be machined again, and in this case, the fabrication is extremely easy, especially since the process can be performed by drilling.

Then, the material of the carburetor main body 1 thus formed is further processed at desired locations, and then various parts as shown in FIG. 9 are assembled and manufactured.

That is, the carburetor main body 1 has an intake passage 2 passing through it, and a throttle valve 10 is rotatably arranged on the engine side of the carburetor body 1 on a throttle valve shaft 11. Bypass hole 1 connected to
2 and a pilot outlet hole 13, and a float chamber 15 is formed by a float body 14 disposed corresponding to one side of the carburetor body 1. A float 16, a valve seat disposed in a fuel inflow path (not shown), and a float valve are arranged in the float chamber 15, and a constant liquid level T-T is always formed by the cooperation of these elements. The reference numeral 17 particularly shown in FIG. A cylindrical ventilly forming part 1 that forms a
7A and a plate-shaped guide portion 17B provided to protrude laterally from the side surface along the longitudinal axis direction Y-Y of the ventilee forming portion 17A. As described above, in this negative pressure operated valve 17, the ventilate forming portion 17A is slidably guided and held in the ventilate forming portion guide groove 7A of the guide member 7, and the plate-shaped guide groove 7 of the guide member 7
At E, the plate-shaped guide portion 17B is slidably guided and held.

Further, a partitioning body 18 such as a diaphragm or a cylinder is integrally arranged above the negative pressure operating valve 17, and an atmospheric chamber 19A is formed by this partitioning body 18 and the upper recess of the carburetor main body 1. A pressure receiving chamber 19B is formed by the body 18 and the cap 20 covering its upper part, and this atmospheric chamber 19A is communicated with the atmosphere via an atmospheric air introduction passage (not shown). Negative pressure of the ventilate V is introduced through a small hole 17C opened at the bottom of the forming portion 17A. In addition, a needle jet 22 is opened in the ventilate V and is connected to a constant liquid level T-T in the float chamber 15 via a main jet 21. The jet needle 23 is inserted and arranged, and the gap formed by the jet needle 23 and the needle jet 22 is adjusted by raising and lowering the negative pressure operating valve 17, and the air-fuel mixture is sucked into the intake passage 2. Amount controlled. Reference numeral 24 denotes a spring whose one end is engaged with the negative pressure operating valve 17 and the other end is engaged with the cap 20 so as to apply a downward force to the negative pressure operating valve 17. The synergistic effect of the plate-shaped guide groove 11 and the ventilate forming portion 17A makes it possible to provide a constant vacuum type carburetor with extremely high suction efficiency and excellent fuel controllability.

According to the constant vacuum type vaporizer according to the present invention, the ventilate forming part guide groove 7A is
By preparing a guide member 7 having a plate-shaped guide groove 7B and a through hole 7C, and inserting this guide member 7 into a guide groove 6 formed in an atmospheric chamber recess 3 of a carburetor main body 1. The ventilary forming part 17A of the negative pressure operating valve 17 and the plate-shaped guide part 17C are slidably guided and held, and the plate-shaped guide groove 7E, which is particularly difficult to cast out in the carburetor main body 1, is used as a guide member. 7, the vaporizer main body 1
It is only necessary to drill a plate-shaped guide groove 7B whose plate width is increased compared to the plate width of the plate-shaped guide groove 7E.
Casting B can now be performed extremely easily. Furthermore, since the guide member 7 is completely independent of the carburetor main body 1, the plate-shaped guide groove 7E can be precisely formed using a cutting tool such as a metal saw with high precision. Further, when changing the diameter of the negative pressure operated valve 17 in setting the engine, it is sufficient to simply change the guide member 7, and the versatility can be improved. Furthermore, if it is necessary to reduce the sliding friction with the negative pressure operated valve 17, this can be easily done by simply changing the material etc. of the guide member 7.

As described above, according to the method for manufacturing a constant vacuum type carburetor according to the present invention, the air is raised and lowered in the intake passage by the negative pressure generated in the intake passage on the upstream side of the throttle valve. In a constant vacuum vaporizer equipped with a negative pressure operated valve consisting of a plate-shaped guide part protruding from the side surface along the axial direction,
A guide member having a guide groove for slidingly guiding and holding the ventilium forming part and the plate-shaped guide part from the atmospheric chamber recess opening on the side of the carburetor main body is fitted and arranged, and the negative pressure operated valve is operated by the guide member. Since it is held in a sliding guide, the castability of the carburetor body is particularly improved.
On the other hand, since the guide member is made separate from the carburetor main body, it is possible to improve the machining accuracy of the plate-shaped guide groove, and it is possible to significantly improve the manufacturability and obtain an inexpensive constant vacuum type carburetor. It is.

In addition, when reducing the frictional force with the negative pressure operated valve or changing the diameter of the negative pressure operated valve, you can simply change the guide member and do not need to make any changes to the carburetor body, making it a highly versatile constant vacuum type vaporizer. It is possible to provide equipment.

[Brief explanation of the drawing]

The figures show an embodiment of the method for manufacturing a constant vacuum type vaporizer according to the present invention, in which Fig. 1 is a longitudinal cross-sectional view of the material of the vaporizer main body, Fig. 2 is a top plan view of Fig. 1,
Fig. 3 is a longitudinal cross-sectional view taken along line - in Fig. 1, Fig. 4 is a longitudinal cross-sectional side view of the guide member, Fig. 5 is a top plan view of Fig. 4, and Fig. 6 is a longitudinal cross-section taken along - line in Fig. 5. FIG. 7 is a side view, FIG. 7 is a perspective view of the guide member, FIG. 8 is a top plan view showing the guide member fitted into the carburetor body, and FIG. 9 is a vertical cross-section of the carburetor body with desired components installed. 10 are perspective views of the negative pressure operated valve. 1... Carburetor body, 2... Intake path, 3... Atmospheric chamber recess, 6... Guide groove, 6A... Central tube groove, 6
B... Plate groove, 7... Guide member, 7A... Ventilation forming portion guide groove, 7B... Plate guide groove, 17... Negative pressure operated valve.

Claims (1)

[Scope of Claims] 1. A constant vacuum carburetor equipped with a negative pressure operated valve that controls the intake passage by negative pressure generated in the intake passage upstream of the throttle valve; A negative pressure actuated valve is formed by a ventilary forming part that forms a ventilary forming part, a plate-shaped guide part that protrudes laterally from the side surface along the longitudinal axis of the ventilizing part, and a negative pressure operated valve that is formed by a It has a cylindrical part, has plate-like parts on both sides of the central cylindrical part and below, and has a ventilary forming part guide groove in the central cylindrical part that slides and guides the ventilary forming part of the negative pressure operated valve. and a guide member formed with a plate-shaped guide groove for slidingly guiding a plate-shaped guide part of a negative pressure operated valve in each plate-shaped part; a central cylindrical groove that has the same shape as the central cylindrical portion of the guide member and opens into the intake passage from the upper opening of the guide member; and a guide member that extends to the side of the central cylindrical groove and extends from the upper opening of the atmospheric chamber recess to approximately the bottom of the intake passage. The guide member is fitted and arranged in the guide groove of the carburetor body, and the guide groove of the ventilary forming part of the guided member and the plate-shaped guide groove are provided. , a ventilary forming part of the negative pressure operated valve within;
A method for manufacturing a constant vacuum vaporizer in which a plate-shaped guide portion is slidably arranged.