JPS6115234Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a throttle valve linkage mechanism for a carburetor.

In a compound type carburetor equipped with a primary side carburetor and a secondary side carburetor, the primary side throttle valve is designed such that the secondary side throttle valve opens when the primary side throttle valve opens a predetermined opening degree or more. A carburetor is known in which a shaft and a secondary throttle valve shaft are connected to each other via a link mechanism, and as such a link mechanism, one end of a tightening lever is rotatably attached to the primary throttle valve shaft. At the same time as mounting, a first claw is formed on one end as described above, and an arm is fixed to the secondary throttle valve shaft that is biased in the valve closing direction, and a pin attached to the tip of the arm is formed on the other end of the tightening lever. an arm that fits into the slit and further has a second claw that can engage with the first claw;
When the primary throttle valve reaches a predetermined opening degree or more, the first pawl and the second pawl engage to rotate the tightening lever, thereby opening the secondary throttle valve. A link mechanism is known. However, in such a link mechanism, no external force is applied to the tightening lever until the first pawl and second pawl engage, and furthermore, the pin of the secondary throttle valve arm and the slit of the tightening lever are loosely engaged. Therefore, the knock lever vibrates in resonance with the vibration of the engine, and as a result, there is a problem that both the pin of the secondary throttle valve arm and the slit of the knock lever are worn out.

SUMMARY OF THE INVENTION The object of the present invention is to provide a link mechanism which prevents the vibration of the tightening lever and prevents wear of the pin of the secondary throttle valve arm and the slit of the tightening lever.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIGS. 1 to 3, the carburetor, which is generally designated by the reference numeral 1, has a primary carburetor A and a secondary carburetor B. The primary side carburetor A includes a primary side throttle valve 3 and a primary side main nozzle 4 in its primary side air horn 2. It is connected to the carburetor float chamber 5. On the other hand, the secondary side carburetor B includes a secondary side throttle valve 7 in its secondary side air horn 6, a secondary side main nozzle 8 disposed upstream of the secondary side throttle valve 7, and a secondary side main nozzle 8 disposed upstream of the secondary side throttle valve 7. 8, and an air valve 9 disposed upstream of the air valve 8. Shafts 10 and 2 of the primary throttle valve 3
The shafts 11 of the downstream throttle valves 7 are connected to each other via a link mechanism 12, and when the primary throttle valve 3 opens to a predetermined opening degree or more, the secondary throttle valve 7 is opened. Referring to FIGS. 5 and 6, the link mechanism 12 includes a lock lever 13 rotatably attached to the primary throttle valve shaft 10 and an arm 14 fixed to the primary throttle valve shaft 10. do.
Further, an arm 16 is fixed to the shaft 11 of the secondary throttle valve 7 which is biased in the valve closing direction by a coil spring 15, and a pin 17 is fixed to the tip of this arm 16. On the other hand, Kitsclever 13
A curved and extending slit 18 is formed at the tip of the pin 17, and a pin 17 is fitted into the slit 18. On the other hand, a first pawl 19 is formed at the end of the tightening lever 13 on the opposite side to the slit 18, and a second pawl 20 that can be engaged with the first pawl 19 is connected to the arm 1.
It is integrally formed on 4. Furthermore, a damper spring 21 is inserted into the primary throttle valve shaft 10.
One end of this damper spring 21 is latched to the first claw 19, and the other end of the damper spring 21 is hooked to the second claw 2.
It is latched at 0. This damper spring 21 urges the lever 13 and the arm 14 in a direction that moves the first pawl 19 and the second pawl 20 away from each other. Therefore, during idling as shown in FIG. 5, the pin 17 is held pressed against the upper edge of the slit 18 by the spring force of the damper spring 21. When the primary throttle valve 3 opens more than a predetermined opening degree, the first pawl 19 opens.
When the second pawl 20 engages with the lock lever 13, the lock lever 13 is rotated counterclockwise, thereby opening the secondary throttle valve 7. In addition, arm 14
A pawl 22 integrally formed at the lower end of the throttle valve 7 engages with the tightening lever 13 to forcibly close the secondary throttle valve 7 when the secondary throttle valve 7 is held open for some reason. fulfill one's role.

On the other hand, as shown in FIGS. 2 and 3, the secondary main nozzle 8 is composed of a hollow cylindrical body 23, and this hollow cylindrical body 23 extends over the entire diameter along the diameter of the secondary air horn 6. Further, on both side wall surfaces of the hollow cylindrical body 23, a plurality of nozzle ports 24 are formed at predetermined intervals and open in a direction perpendicular to the flow direction of the intake air. A fuel passage 25 is formed inside the hollow cylinder 23 and is connected to the float chamber 5 via a main fuel passage 26 and a fuel metering jet 27.

The air valve 9 is fixed to an air valve shaft 28 at an eccentric position offset from its center, and a cam 29 is fixed to a projecting outer end of the shaft 28 that projects outward from the carburetor housing. As shown in FIG. 4, the cam surface 30 of the cam 29 is formed such that the distance from the axis of the shaft 28 increases in the counterclockwise direction. Furthermore, as shown in FIG. 3, a coil spring 31 is installed between the protruding end of the air valve shaft 28 on the opposite side of the cam 29 and the carburetor housing, and the spring force of this coil spring 31 causes the air valve 9 to move. Always biased in the valve closing direction. As shown in FIG. 4, a lever 32 is mounted on the carburetor housing in permanent contact with the cam surface 30 of the cam 29. One end of this lever 32 is pivotally connected to the carburetor housing via a pivot pin 33, and a metering needle 34 is attached to the other end of the lever 32. Metering needle 34
is inserted into a hole (not shown) formed in the lever 32, and the lever 32 is inserted into the metering needle 3 by a compression spring 36 inserted on a spring retainer 35 fixedly disposed on the metering needle 34.
It is brought into pressure contact with the enlarged head 37 of No. 4. On the other hand, the lower end 38 of the metering needle 34 is tapered, and this tapered lower end 38 fits into the metering jet 27 to control the flow cross section of the metering jet 27.

When the opening degree of the primary throttle valve 3 is less than or equal to a predetermined opening degree, the secondary throttle valve 7 is in a fully closed state. At this time, as shown in FIG. 2, the air valve 9 is also in a fully closed state, and the cross section of the flow path of the metering jet 27 is at its minimum. Next, when the primary throttle valve 3 reaches a predetermined opening degree or more, the secondary throttle valve 7 opens, and the air suction operation from the secondary air horn 6 is started. At this time, the air valve 9 is
The valve is opened to an opening degree at which the rotational force in the valve-opening direction due to the pressure difference between the upstream and downstream sides of the valve is balanced with the rotational force in the valve-closing direction due to the coil spring 31. When the air valve 9 is opened in this way, the cam 29 also rotates, so the lever 32 is rotated clockwise, and as a result, the metering needle 34 is lifted, so that the cross section of the flow path of the metering jet 27 is changed. be made to increase. In this way, the flow path cross section of the metering jet 27 is controlled according to the opening degree of the air valve 9,
In this way, the amount of fuel ejected from each nozzle port 24 of the secondary side main nozzle 8 is controlled according to the opening degree of the air valve 9.

According to the present invention, by providing a damper spring between the arm fixed to the primary throttle valve shaft and the tighten lever, one side edge of the slit of the tighten lever is always pressed against the pin of the secondary throttle valve arm. Can be done. As a result, since the vibration of the tightening lever is prevented, wear of the slit of the tightening lever and the pin of the secondary throttle valve arm can be prevented, and good link operation can be ensured at all times.

[Brief explanation of the drawing]

Fig. 1 is a plan view of a vaporizer according to the present invention, Fig. 2 is a partially sectional side view taken along the - line in Fig. 1, and Fig. 3 is a side sectional view taken along the - line in Fig. 1. 4 is a side view taken along the arrow in FIG. 3, FIG. 5 is a side view of the link mechanism shown in FIG. 2, and FIG. 6 is a plan view of FIG. 5. 3... Primary side throttle valve, 7... Secondary side throttle valve, 10, 11... Shaft, 12... Link mechanism, 13... Knock lever, 14, 16...
...Arm, 17...Pin, 18...Slit, 1
9...first claw, 20...second claw, 21...damper spring.

Claims (1)

[Scope of utility model registration request] One end of the lock lever is rotatably attached to the shaft of the primary throttle valve, and a first pawl is formed on the one end, and the secondary throttle valve is attached to the shaft of the secondary throttle valve in a normally closed direction. At the same time, an arm is fixed to the secondary throttle valve shaft, a pin attached to the tip of the arm is loosely fitted into a slit formed at the other end of the lock lever, and the first An arm having a second pawl that can be engaged with the pawl is fixed to the primary throttle valve shaft, and when the primary throttle valve reaches a predetermined opening or more, the first pawl and the second pawl are fixed to the primary throttle valve shaft. engages and rotates the tightening lever,
In the carburetor which opens the secondary throttle valve thereby, the arm and the tightening lever are arranged between the arm fixed to the primary throttle valve shaft and having the second claw and the tightening lever so as to be opposite to each other. A carburetor throttle valve link mechanism equipped with a damper spring that biases in the direction of rotation.