JPS6238549B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to means for preventing readjustment after final adjustment of an idle fuel adjustment screw of an internal combustion engine carburetor.

FIG. 1 shows a longitudinal cross-sectional view of an example of a conventional low-velocity fuel passage system for an internal combustion engine carburetor of the type disclosed in U.S. Pat. No. 3,618,906. In the figure, 1 is a carburetor throttle chamber, 2 is an inner wall surface of an intake passage of the throttle chamber 1, 3 is a throttle valve, 4 is a low-speed fuel passage formed in the throttle chamber 1,
Reference numeral 5 denotes a bypass port that communicates with the low-speed fuel passage 4 and opens on the inner wall surface 2 of the intake passage at a position just upstream of the closed position of the throttle valve 3; and 6, an insertion hole that penetrates the outer wall of the throttle chamber 1. 7 and is inserted from the low speed fuel passage 4 to the bypass port 5.
A plug pin 8 whose tip portion is inserted into the fuel flow path leading to the fuel flow path communicates with the low-speed fuel passage 4 and opens at a position immediately downstream of the closed position of the throttle valve 3 on the inner wall surface 2 of the intake passage. idle port, 9
is screwed through a screw hole 10 provided on the outer wall of the throttle chamber 1, and its tip part is inserted into the fuel flow path leading from the low-speed fuel passage 4 to the idle port 8 to adjust the idle fuel injection amount. 11 is an adjustment knob formed on the outer end of the adjustment screw 9; 12 is an idle adjustment screw 11 formed on the outer end of the adjustment screw 9;
1 and the outer wall surface of the throttle chamber 1. The idle adjustment screw 9 is used to adjust the amount of idle fuel ejected from the idle port 8 to the optimum amount in the final process of manufacturing the carburetor, and then to prevent harmful operations by the market or the driver. It is necessary to set it up.
Conventionally, as a means for this, a limiter cap 13 as shown in FIG. Normally, rotation of the adjustment screw 9 is reliably prevented by press-fitting it into a blind hole 16 formed from the outer wall surface of the torque chamber 1.

However, in the conventional adjusting screw rotation prevention method as described above, an increase in manufacturing cost due to the extra material and manufacturing process of the stop pin 15 and the blind hole 16 as described above is unavoidable. Moreover, there have been cases where the compressed and high-pressure air trapped in the blind hole 16 when the stop pin 15 was press-fitted led to expansion and deformation of the constituent members of the throttle chamber 1.
Furthermore, as mentioned above, the expansion force when the enclosed high-pressure air is exposed to high temperatures causes the stop pin 1 to
5 may slip out and cause an accident in which the desired anti-rotation effect is lost. Furthermore, even if air escape holes are provided as a countermeasure, an increase in cost cannot be avoided.

The present invention aims to solve the above-mentioned difficulties in the conventional method of preventing readjustment of the idle adjustment screw, and has the features described in the claims section above.

FIG. 2 shows a longitudinal cross-sectional side view of one embodiment of the present invention, and each reference numeral 1 to 14 indicates the same target portion as in FIG. 1. In this example,
Stop pin 15 as shown in the conventional example in FIG.
The blind hole 16 is not formed, and instead, the outer end side of the plug pin 6 is extended to protrude from the outer wall of the throttle chamber 1 with respect to the bypass port 5, which was also formed in the conventional example shown in FIG. Part 17
A feature of the present invention is that the extension portion 17 is inserted and fixed into the insertion hole 14 provided on one side edge of the limiter cap 13.

As is clear from the above description, according to the present invention, there is no need to provide the stop pin 15 and the blind hole 16 for press-fitting it as in the conventional example shown in FIG. port 5
By simply making the plug pin 6 slightly longer, it can be used to prevent the limiter cap 13 from rotating.
Production costs can be reduced by saving and shortening the raw materials and production of this type of product. Moreover, when the plug pin 6 is inserted into the insertion hole 7, its inner tip is open into the low-speed fuel passage 4, so that it can be press-fitted with a stop pin, etc., like the blind hole 16 in the conventional example shown in FIG. There is no place where air is compressed, and therefore there is no possibility of an accident occurring due to the expansion force of the compressed air sealed in the blind hole 16 as in the prior art example described above.

[Brief explanation of the drawing]

FIG. 1 is a vertical side view of a conventional example, and FIG. 2 is a vertical side view of an embodiment of the present invention. 1... Throttle chamber, 2... Intake passage inner wall surface, 3... Throttle valve, 4... Low speed fuel passage, 5...
Bypass port, 6...Plug pin, 7...Insertion hole, 8...Idle port, 9...Adjustment screw, 1
0...screw hole, 11...knob, 12...spring,
13... Limiter cap, 14... Insertion hole, 1
5...stop pin, 16...blind hole, 17...extension part.

Claims (1)

[Claims] 1. In a low-speed fuel passage system having a bypass port that opens at a position immediately before the upstream side of the throttle valve closing position on the inner surface of the carburetor intake passage, and an idle port that opens at a position immediately downstream of the throttle valve closing position, the idle port The outer end of a plug pin inserted into the fuel flow path for the bypass port is inserted and fixed into the insertion hole provided on the side edge of the outer end shielding cap of the idle fuel adjustment screw for the bypass port. carburetor idle adjustment prevention device.