JPS63272956A - Manufacture of slide throttle valve type carburetor - Google Patents

Abstract

PURPOSE:To enable precise positioning in connecting a jet block to a throttle valve guide hole open to the lower recess of a carburetor proper by using positioning projections formed on the external surface of a jet block insertion part for the positioning of the jet block. CONSTITUTION:A throttle valve guide hole 3 open to the lower recess of a carburetor proper 1 is so formed as to have approximately the same shape as a slide throttle valve 4 including the side 4A of circular arc shape opposing an engine. And a seat 1B is extended sideward from the lower end 3A of said guide hole 3. On the other hand, a jet block 8 closing the throttle valve guide hole 3 is made to have an insertion part so formed thereon as to agree approximately thereto, and a seat part 8C to be connected to the seat 1B is extended sideward from the lower end of said insertion part. Also, a positioning projection 8D along the direction X of the major axis of an intake passage 2 and another positioning projection 8E along the Y direction are formed on the external surface of the insertion part. The insertion part of the jet block 8 is positioned and arranged in the guide hole 3 via the positioning projections 8D and 8E.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a carburetor that adjusts and controls the amount and concentration of air-fuel mixture supplied to an engine, and in particular relates to a carburetor that adjusts and controls the amount and concentration of air-fuel mixture supplied to an engine, and particularly relates to a carburetor that has a throttle valve connected to an intake passage. This invention relates to a sliding throttle valve type carburetor that is movably disposed within a guide hole and is often used as a carburetor for motorcycle engines.

[Conventional technology]

Conventionally, as mentioned above, since sliding throttle valve type carburetors are often used in motorcycles, it is particularly important that the intake air supplied to the engine be efficiently produced. It is desirable that the groove remaining on the side of the intake passage of the throttle valve guide hole that guides and holds the valve is as small as possible.
For example, a sliding throttle valve is constructed of a side surface facing the engine side and a side surface facing the air cleaner side, and the side surface facing the engine side is shaped like an arc.

The throttle valve guide hole that slides and guides the sliding throttle valve needs to be machined into the same shape as the sliding throttle valve, and in order to facilitate this process, the throttle valve guide hole is inserted from the top of the carburetor body. A through hole is formed in the lower concave portion, and this lower concave portion is then closed with a jet block, and the insertion portion formed at the end of the jet block for closing the throttle valve guide hole is used as the throttle valve guide hole. It matches the shape of .

[Problem that the invention seeks to solve]

This conventional method of manufacturing a sliding throttle valve type carburetor has the following drawbacks. In other words, the shapes of the throttle valve guide hole and the insertion part formed at the upper end of the jet block are made to match the shape of the sliding throttle valve, and according to this, the - side surface must be formed in an arc shape. .

For this reason, the throttle valve guide hole was made into a through hole, so it was possible to process it accurately by broaching, etc., but the jet block insertion part could be processed accurately by machining it with an NG mill, etc. Although it is possible, the manufacturing cost increases significantly and is not desirable for mass production, so conventionally, it is used in the molded state.

According to this, it is particularly difficult to accurately position the arcuate side surface facing the engine side with respect to the throttle valve guide hole, and the position of the jet block varies with respect to the throttle valve guide hole. The relative position of the bypass hole with respect to the lower end of the sliding throttle valve and the relative position of the needle jet with respect to the jet needle attached to the sliding throttle valve are inaccurate, making it impossible to obtain a uniform air-fuel mixture supply. . (The bypass hole and the needle jet are arranged in the jet block.) [Means for solving the problem] The sliding throttle valve type carburetor according to the present invention was created in view of the above-mentioned problems, and has the following features: The purpose is to precisely place the jet block in the throttle valve guide hole to ensure accurate supply of air-fuel mixture.To achieve this purpose, a throttle valve guide hole is placed in the intake passage that passes through the carburetor body. The throttle valve guide hole is configured with a side surface facing the first engine side and a side surface facing the air cleaner side, with only the side surface facing the engine side having an arc shape;
A sliding throttle valve with a jet needle arranged at the bottom is slidably arranged, and a fuel system is provided inside the throttle valve guide hole that passes through the intake passage from the top of the carburetor body to the lower concave part of the carburetor body. In a sliding throttle valve type carburetor that is closed and joined by a jet block, the throttle valve guide hole that opens into the lower concave portion of the carburetor body has approximately the same shape as the sliding throttle valve, and the lower end of the throttle valve guide hole The jet block is provided with a seat portion extending further to the side, and the jet block is provided with an insertion portion at its upper portion that approximately matches the throttle valve guide hole that opens in the lower recess of the carburetor main body, and the jet block is provided with an insertion portion that approximately matches the throttle valve guide hole that opens in the lower recess of the carburetor main body. In addition to providing a seat part to be joined to the seat part of the carburetor main body on the side,
A positioning protrusion along the longitudinal axis direction x-X of the intake passage and a positioning protrusion perpendicular to the longitudinal axis direction x-X of the intake passage are provided on the outer periphery of the insertion portion, and the insertion portion of the jet block is The jet block is positioned in the throttle valve guide hole with a positioning protrusion, and the seat part of the jet block is joined to the seat part of the carburetor main body.

[Effect]

Positioning protrusions are provided on the outer periphery of the insertion portion of the jet block in the perpendicular direction, and the jet block can be placed in the throttle valve guide hole by the positioning protrusions.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a sliding throttle valve type carburetor according to the present invention will be described below with reference to the drawings.

1 is a carburetor body through which an intake passage 2 passes through, and the lower recess 1 of the carburetor body 1 is passed through the intake passage 2 from the upper part.
A throttle valve guide hole 3 is bored toward A.

A sliding throttle valve 4 is movably disposed within this throttle valve guide hole 3, and the shape of the sliding throttle valve 4 is a third one.
As shown in the figure, it is formed by a side surface 4A facing the engine side (on the left side in the figure) and a side surface 4B facing the air cleaner side, and the side surface 4A facing the engine side is formed in an arc shape.

Therefore, the shape of the throttle valve guide hole 3 is the same as that of the sliding throttle valve 4 described above.
The shape is approximately in agreement with the shape of .

Further, a float chamber main body 5 is disposed at the lower part of the carburetor main body 1, and a float chamber 6 is formed by the vaporizer main body 1 and the float chamber main body 5. A constant liquid level is created by the valve seat and float valve.

To explain the throttle valve guide hole 3 in more detail, the lower end 3A of the throttle valve guide hole 3 (which has approximately the same shape as the sliding throttle valve 4) opens into the lower recess 1A of the carburetor main body l; For example, a planar sheet portion IB is arranged to extend laterally in all directions from the lower end portion 3A.

On the other hand, 8 is a jet block for blocking the throttle valve guide hole 3, and this includes a main jet 9. Main fuel system M consisting of needle jet 10 etc. and slow jet 1
1. A low-speed fuel system S consisting of a bypass hole 12 and the like is arranged.

In the upper part of the jet block 8, there is formed an insertion part 8B which has approximately the same shape as the lower end part 3A opening into the lower recess 1A of the carburetor main body l and which is inserted into the lower end part 3^. A seat portion 8C is formed laterally by the lower end of 8B to be joined to the seat portion 1B of the carburetor main body l.

What is particularly characteristic is that the outer periphery of the insertion portion 8B in the upper part of the jet block 8 has a
The positioning protrusion 8D and the longitudinal axis direction of the intake passage along x-X
These x
The jet block 8 is positioned within the lower end 3A of the throttle valve guide hole 3 by the positioning protrusion 80.8E arranged in the -Y direction.

still,! 3 is a jet needle disposed in the sliding throttle valve 4 and placed in the needle jet 10; 14 is a seat portion IB of the carburetor main body l and a seat portion 8 of the jet block 8;
This is a sealing member disposed between C and C.

Next, the connection between the jet block 8 and the throttle valve guide hole 3 will be explained.

Jet block 8 from the lower recess IA side of the carburetor body l
Insert into the lower end 3A of the throttle valve guide hole 3 of the insertion part 8B of the E part of the jet block 8, and seat part 8C of the jet block 8.
is joined to the seat portion 1B of the carburetor main body 1. At this time, the positioning protrusion 8D and EIE protruding from the insertion portion 8B of the jet block 8 come into close contact with the lower end 3A of the throttle valve guide hole 3, so the jet block 8 can be joined to the throttle valve guide hole 3 with high accuracy. It is something.

〔Effect of the invention〕

As described above, according to the method of manufacturing a sliding throttle valve type carburetor according to the present invention, the joint between the jet block and the lower end of the throttle valve guide hole is at the outer periphery of the insertion portion of the jet block, and Since the position is determined only by the positioning protrusions arranged in the Y direction, it is only necessary to maintain the dimensional accuracy of the positioning protrusions, which makes it possible to maintain accurate positioning dimensions in an extremely simple manner.

Especially when manufacturing a jet block by molding, if the positioning protrusion is replaced with a pin during mold manufacturing, it will be easy to maintain its accuracy, and even if the pin wears out during manufacturing, it can be replaced by replacing the pin. Maintenance is also easy.

Note that the number and position of the two positioning protrusions are appropriately selected in the x-y directions.

[Brief explanation of drawings]

The drawings show an embodiment of the method for manufacturing a sliding throttle valve type carburetor according to the present invention, in which Fig. 1 is a longitudinal sectional view, and Fig. 2
The figure is a top plan view with the top cover and sliding throttle valve removed.
FIG. 3 is a top plan view of only the sliding throttle valve. 190. Carburetor body, 1B, Seat part, 261.
Inhalation tract, 361. Throttle valve guide hole, 3A, lower end,
800. jet block. 8D, 8E, positioning protrusion, 8B, insertion part,
8G... Seat part

Claims (1)

[Claims] A throttle valve guide hole is installed in the intake path that passes through the carburetor body,
In the throttle valve guide hole, a sliding throttle valve is slidably constructed of a side surface facing the engine side and a side surface facing the air cleaner side, only the side surface facing the engine side is arcuate, and a jet needle is disposed at the bottom. In a sliding throttle valve type carburetor, the throttle valve guide hole, which passes through the upper part of the carburetor body through the intake path and penetrates into the lower recessed part of the carburetor body, is closed and joined with a jet block that has a fuel system inside. , the throttle valve guide hole 3 that opens in the lower recess 1A of the carburetor main body 1 has approximately the same shape as the sliding throttle valve 4, and the throttle valve guide hole 3
A seat portion 1B is provided extending laterally from the lower end portion 3A,
On the other hand, the jet block 8 has a carburetor main body 1 on its top.
An insertion part 8B is provided which approximately matches the throttle valve guide hole 3 opening in the lower recess 1A of the carburetor main body 1, and a seat part 8C is provided laterally by the lower end of the insertion part to be joined to the seat part 1B of the carburetor main body 1. A positioning protrusion 8D along the longitudinal axis direction XX of the intake passage 2 and a positioning protrusion 8E along YY orthogonal to the longitudinal axis direction XX of the intake passage 2 on the outer periphery of the portion 8B;
is provided, the insertion portion 8B of the jet block 8 is positioned in the throttle valve guide hole 3 with the positioning protrusions 8D and 8E, and the seat portion 8C of the jet block 8 is joined to the seat portion 1B of the carburetor main body 1. A method for manufacturing a sliding throttle valve type vaporizer.