JPH0429070Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an engine throttle device that has an improved throttle shaft that is rotatably operated via an accelerator cable or the like.

(Prior Art and its Problems) In general, in a carburetor, the diameter of the throttle shaft is generally formed to be uniform, as disclosed in Japanese Utility Model Application Publication No. 59-60360. Moreover, the throttle shaft is arranged so that its middle part crosses the intake passage, and in addition to its one end where rotational force is input, the other end can be freely rotated into the shaft mounting hole of the carburetor body. Supported.

In such a carburetor, the clearance between the other end of the throttle shaft, that is, the end farther from the side where the rotational force is input, and its shaft mounting hole is the same as the clearance between the one end where the rotational force is inputted and the end thereof. The clearance may be smaller than the clearance between the shaft mounting hole and the shaft mounting hole. In such a case, when rotational force is input to one end of the throttle shaft, the bending moment tends to concentrate near the other end of the throttle shaft, and the torsional moment at this other end tends to increase. be.

By the way, some carburetors are of a dual type in which one air intake port is divided midway into two intake passages, a primary side and a secondary side. In this dual carburetor, the cross-sectional area of the primary intake passage is small, so in order to minimize the intake resistance of the primary intake passage, the diameter of the primary throttle shaft cannot be made too large. For this reason,
If the above-mentioned bending moment or torsional moment concentrates on the other end of such a thin throttle shaft and its vicinity, there is a risk that the throttle shaft will break near the other end, so these forces will be transferred to the other end. Some kind of countermeasure should be taken to prevent the throttle shaft from breaking even if the damage is concentrated near the part.

(Purpose of the invention) Therefore, the purpose of the invention is to provide an engine throttle device that further improves the strength of the throttle shaft and prevents its breakage while suppressing the increase in intake resistance as much as possible. It is in.

(Means and actions for achieving the object) In order to achieve the above-mentioned object, the present invention improves the strength of the throttle shaft where the force is concentrated to the minimum necessary, thereby making the throttle shaft less susceptible to bending moment. Will not break even if subjected to torsional moment,
Moreover, the intake resistance is prevented from increasing. Specifically, a throttle shaft is rotatably held by the throttle body so as to cross an intake passage formed in the throttle body, a throttle valve is attached to a portion of the throttle shaft that crosses the intake passage, In the engine throttle device in which one end of the throttle shaft extends outside the throttle body to apply rotational force to the one end, the throttle shaft has a portion that crosses the intake passage. The one end side is formed thinner than the other end side with a predetermined position as a boundary.

With this configuration, the diameter of the other end of the throttle shaft is made thicker, ensuring sufficient strength.However, since this thickened part is only on the other end, the throttle shaft can be extended over its entire length. The intake resistance is much smaller than that in the case where it is made thicker over the entire length.

(Example) An example of the present invention will be described below based on the attached drawings.

In FIGS. 1 to 3, reference numeral 1 indicates a carburetor main body of a double-barreled carburetor. In a carburetor main body 1 constituting a throttle body, one air intake port 2 and a primary side intake passage 3 and a secondary side intake passage 4 which are parallel to each other and communicate with each air intake port 2 are formed. Further, in the carburetor body 1, a pair of shaft mounting holes 5, 6 are opened in radially opposite parts of the primary intake passage 3 and are located on the same line orthogonal to the primary intake passage 3. is formed.

One end 7a of the primary throttle shaft 7 is rotatably fitted into one shaft mounting hole 5, and the other end 7b of the primary throttle shaft 7 is rotatably fitted into the other shaft mounting hole 6. Fitted and supported. Primary throttle shaft 7 that crosses the primary intake passage 3
The diameter A of the other end 7b and a portion extending from this portion to near the center of the primary intake passage 3 is formed to be slightly larger than the diameter B of the one end 7a side. As a result, the strength of the other end 7b side is higher than that of other parts. A primary throttle valve 8 disposed within the primary intake passage 3 is fixed to the intermediate portion of the primary throttle shaft 7, and an accelerator cable is connected to one end 7a of the valve extending outside the carburetor body 1. A drive member 9 that is rotatably operated by a screw (not shown) is fixed, and furthermore, a drive member 9 that is rotated by a
A return spring 11 is interposed between the primary throttle valve 8 and a spring receiver 10 fixed to the primary throttle valve 8, which biases the primary throttle valve 8 in the opening direction.

The secondary carburetor passage 4 is opened and closed by a secondary throttle valve 13 mounted on a secondary spring shaft 12. Further, while a link 14 is fixed to the end of the secondary throttle shaft 12,
A link 1 is provided at one end 7a of the primary throttle shaft 7.
5 is held rotatably, and both links 1
4 and 15 are connected via a link 16. Moreover, by operating the accelerator cable to rotate the drive member 9, the primary throttle valve 8
When the valve is opened to a predetermined angle, the arm 17 integrated with the primary throttle shaft 7 comes into contact with the claw portion 15a of the link 15. When the drive member 9 is further rotated, the secondary throttle valve 13 moves between the arm 17 and the link 14. ,1
5, 16, so that it can be rotated in the opening direction. Note that the secondary side intake passage 4 has a large diameter and intake resistance does not pose much of a problem.
The diameter of the secondary throttle shaft 12 is substantially the same over its entire length so as to have sufficient strength.

In the above configuration, the drive member 9
When rotating the next throttle shaft 7, that is, the fourth
When a rotational force as shown by arrow F in the figure is applied to one end 7a, even if a bending moment and a torsion moment are applied to the other end 7b of the primary throttle shaft 7, the other end 7b is thicker than the other end 7b. Since the primary throttle shaft 7 is formed to have high strength, there is no possibility that the primary throttle shaft 7 will break from the other end 7b side. In addition, in the part of the primary throttle shaft 7 facing the primary intake passage 3, only the other end 7b side is made thicker, and the other end is thinner, so that the increase in intake resistance caused by the primary throttle shaft 7 can be minimized. It can be suppressed.

In the embodiments described above, the present invention is applied only to the primary throttle shaft 7, but the present invention can be similarly applied to the secondary throttle shaft 12. Moreover, it goes without saying that the present invention can be applied to vaporizers other than double-barrel vaporizers. Furthermore, in the case of a device having a fuel injection valve instead of a carburetor, it can be similarly applied to a so-called throttle body portion.

(Effects of the Invention) As is clear from the above description, the present invention can suppress an increase in intake resistance, improve the strength of the throttle shaft, and prevent its breakage.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an example of a dual carburetor to which the present invention is applied. FIG. 2 is a sectional view taken along the - line in FIG. 1. Figure 3 is a right side view of Figure 1. FIG. 4 is an explanatory diagram of the operation of the throttle valve shown in FIG. 1. 1... Carburetor main body, 3... Primary side intake passage,
5, 6...Shaft mounting hole, 7...Primary throttle shaft, 7a...One end, 7b...Other end, 8...Throttle valve, F...Turning force

Claims (1)

[Claims for Utility Model Registration] A throttle shaft is rotatably held by the throttle body so as to cross an intake passage formed in the throttle body, and a throttle valve is provided at a portion of the throttle shaft that crosses the intake passage. In the engine throttle device, the throttle shaft is mounted so that one end of the throttle shaft extends outside the throttle body to apply rotational force to the one end, wherein the throttle shaft crosses the intake passage. 1. A throttle device for an engine, wherein the one end is narrower than the other end with respect to a predetermined position of the throttle section.