JP2684380B2 - Vaporizer valve operation mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a carburetor for a small internal combustion engine mounted on a portable work machine or the like, in particular, a cable for operating a throttle valve is stable and smooth in operation. The present invention relates to a valve operation mechanism of a vaporizer.

[Prior Art] For example, as in the carburetor disclosed in Japanese Utility Model Laid-Open No. 62-78356, the throttle lever connected to the valve shaft is normally attached to the throttle adjustment bolt on the idle side of the throttle valve by the force of the spring. When the remote control cable is pulled and rotated in the abutted state, the opening degree of the throttle valve is adjusted, and the output of the engine is adjusted accordingly.

The remote control cable consists of an outer tube and an inner cable inserted through the outer tube. One end of the outer tube is fixed to the carburetor body and the other end is fixed to the handle of the working machine. One end of the inner cable is connected to the throttle lever, and the other end is connected to a trigger lever arranged on the handle. At the carburetor body, the inner cable is inserted into the outer tube mounting guide tube fixed to the carburetor body.

[Problems to be solved by the invention] By the way, since the rotation amount of the throttle lever from the idle position to the fully open position reaches 90 ° due to the structure of the throttle valve, the guide tube of the inner cable is accompanied by the operation of the throttle lever. The angle of the insertion portion of the slotter changes drastically, and the force of the inner cable pulling the slottle lever toward the full opening direction of the slottle valve becomes weak near the full opening of the slottle valve, and the smoothness of the operation of the slottle lever is impaired. If the inner cable is pulled strongly in such a state, the entire carburetor will be pulled together with the slot lever, which will deform the inner cable connection part and slot lever, and also the load on the bearing member that supports the valve shaft. There was a problem that the size became large.

If the outer diameter of the throttle valve is increased with a margin,
The operating angle of the throttle valve can be made small, but this makes the carburetor large and is not preferable for the carburetor of a small internal combustion engine.

In view of the above problems, the object of the present invention is to add a new member to the conventional carburetor to reduce the bending of the inner cable, and to make the throttle lever operate smoothly from the idle position to the fully open position. To provide an operating mechanism.

[Means for Solving the Problem] In order to achieve the above-mentioned object, the configuration of the present invention is such that an operation in which a remote operation cable is connected to an end portion of the throttle lever is connected to a valve shaft of the throttle valve so that the remote operation cable is connected to the operation lever. The lever is rotatably supported on the carburetor main body by a shaft parallel to the valve shaft, and one of the throttle lever and the operating lever is supported with an operating pin that abuts the other side edge.

[Operation] Normally, the throttle lever 30 is brought into contact with the end portion of the throttle adjustment bolt 4 by the force of the spring 9, and at the same time, the operation pin 32 is brought into contact with the end side edge of the operation lever 28.

When the operation lever 28 is rotated about the support shaft 29 by the inner cable 5, the operation pin 32 is pushed by the operation lever 28, and the throttle lever 30 is rotated together with the valve shaft 25.
The opening degree of the throttle valve 21 increases.

The operating lever 28 is axially supported by the carburetor main body 2 by a support shaft 27 which is parallel to the valve shaft 25 and is longer than the slot lever 30. Therefore, the operating lever for rotating the slot lever 30 from the idle position to the fully open position is provided. The rotation amount (angle) of 28 becomes smaller. Therefore, the bending angle of the insertion portion of the inner cable 5 connected to the operation lever 28 into the guide tube 7 is very small, the sliding resistance at this portion is small, and the inner cable 5 is changed from the operation lever 28 to the operation lever 28. The rotational force applied from the idle position to the fully open position is substantially constant, and the smoothness of the operation of the operating lever 28 is improved.

[Embodiment of the Invention] As shown in FIG. 1, a block-shaped main body 2 is penetrated by a cylindrical intake passage 1, and an inlet end 1a thereof is an air cleaner and an outlet end 1b thereof is an intake port of an engine. Connected. A cylindrical portion 24 having an open upper end is formed in the main body 2 so as to cross the intake passage 1, and a cylindrical slot valve is formed therein.
21 is rotatably supported. The valve shaft 25 formed at the upper end of the throttle valve 21 is supported by the shaft hole 22 of the bearing member 3 that closes the cylindrical portion 24 of the main body 2. The cylindrical portion 17 provided at the lower end of the throttle valve 21 is fitted to the shaft portion 16 formed on the bottom 12 of the cylindrical portion 24 of the main body 2.

A spring 9 interposed between the bearing member 3 and the throttle valve 21.
Has one end locked to the throttle valve 21 and the other end locked to the bearing member 3. The spring 9 rotatably urges the throttle valve 21 in a direction to throttle the intake passage 1, and the cam groove 34 on the lower surface of the throttle lever 30 coupled to the upper end of the valve shaft 25 has a ball of a column 36 protruding from the bearing member 3. Abut on 38.

The throttle valve 21 is provided with a slot hole 19 capable of communicating with the intake passage 1, and the shaft portion 16 of the main body 2 is inserted into the slot hole 19.
A nozzle tube 15 is projected from the nozzle tube 15. The nozzle pipe 15 is fitted and supported by the cylindrical portion 13 of the shaft portion 16, and the lower end portion of the fuel passage 14 communicates with a metering chamber (not shown) of, for example, a diaphragm type fuel supply mechanism. The opening area of the nozzle hole 18 provided in the nozzle pipe 15 and opening to the downstream side of the intake passage 1 is adjusted by the needle valve 20 fitted into the fuel passage 14 from above. The upper end of the needle valve 20 is connected to the adjusting bolt 23, and the adjusting bolt 23 is used for the valve shaft.
By screwing into the hole 6 of 25 against the force of the spring 10, the protruding position of the needle valve 20 into the slot hole 19 is adjusted.

The cam groove 34 of the throttle lever 30 has an arc shape centered on the valve shaft 25 (see FIG. 2), and the depth of the cam groove 34 is the deepest at the idle position and becomes gradually shallower as it reaches the fully open position. . Therefore, when the throttle lever 30 is rotated from the idle position to the fully open position, the opening degree of the throttle hole 19 with respect to the intake passage 1 gradually increases, and at the same time, the needle valve 20 acts on the force of the spring 9 together with the throttle valve 21. The nozzle holes 18 are pushed up against each other, the opening area of the nozzle holes 18 increases, and the amount of fuel sucked from the fuel passage 14 to the slot holes 19 increases. The configuration of such a rotary throttle valve type carburetor is the same as the conventional one.

According to the present invention, the bracket 26 made of a metal plate or the like is superposed on the bearing member 3 and is joined to the main body 2 together with the bearing member 3 by a plurality of bolts 8 (see FIG. 2).
A support shaft 27 parallel to the valve shaft 25 is fixed to the bracket 26, and a boss portion 28a formed at the base end portion of the operating lever 28 is rotatably fitted to the support shaft 27, and the upper end of the support shaft 27 is prevented from coming off. A seat plate is supported by the bolt 29 on the section. The operating lever 28 extends so as to overlap with the upper side of the throttle lever 30. Operation lever
A small-diameter shaft portion on the lower end side of the swivel 31 is rotatably inserted in the shaft hole 22 of the tip end portion of 28, and a retaining ring 33 is locked so as not to come off. The end of the inner cable 5 is connected to the split groove 31a at the upper end of the swivel 31 by a known means. An operating pin 32 formed by winding a steel plate in a cylindrical shape is fitted and fixed in a shaft hole formed at the end of the slot lever 30.

As shown in FIG. 2, the operating pin 32 is brought into contact with the end side edge of the operating lever 28. The guide tube 7 (which connects one end of the outer tube) is screwed into the screw hole of the mounting wall 26b formed by bending the edge of the bracket 26, and the lock nut 11
Is fixed by The inner cable 5 connected to the operating lever 28 is inserted into the guide tube 7. The other end of the outer tube is fixed to the handle of the working machine, while the other end of the inner cable 5 is connected to a trigger lever axially supported by the handle.

As shown in FIG. 3, the slot adjustment bolt 4 is screwed into the mounting wall 26a formed by bending the edge of the bracket 26, and the end of the slot lever 30 is attached to the end 4a by the force of the spring 9 described above. Are brought into contact with each other (state shown in FIG. 2).

Next, the operation of the valve operating mechanism of the carburetor according to the present invention will be described. In the idle position of the throttle valve shown in FIG. 2, the throttle lever 30 is urged to rotate counterclockwise by the force of the spring 9 shown in FIG. 1, and abuts against the end 4a of the throttle adjustment bolt 4. At the same time, the operating pin 32 is brought into contact with the side edge of the operating lever 28. When the inner cable 5 is pulled by a trigger lever (not shown), the operation lever 28 moves to the spindle 27
It is rotated clockwise around. The operating pin 32 is pushed by the operating lever 28, the valve shaft 25 is rotated clockwise together with the throttle lever 30, and the opening degree of the throttle valve 21 is increased.

The rotation angle of the throttle lever 30 from the idle position to the fully open position is about 90 °, but the rotation angle of the operation lever 28 is small because the operation lever 28 is longer than the throttle lever 30. Therefore, in FIG. 2, the amount of lateral movement of the swivel 31 is small, and the inclination or bending of the inner cable 5 that is inserted from the swivel 31 into the guide tube 7 is extremely small. Sliding friction with the cable 5 is small and operation is stable. In this way, the operation lever 28 is smoothly rotated by the inner cable 5, and the operation lever 28 is rotated.
As a result, the operating pin 32 is pushed, and the throttle lever 30 also smoothly rotates from the idle position to the fully open position.

In the above-mentioned embodiment, even if the operating pin is fixed to the operating lever so as to project downward and the operating pin is brought into contact with the side edge of the slotter lever to rotate the slotter lever, the same result is obtained. The effect is obtained.

[Advantages of the Invention] As described above, according to the present invention, an operation lever having a remote operation cable connected to an end thereof is connected to an axis parallel to the valve shaft so as to overlap with an upper side of the throttle lever connected to the valve shaft of the throttle valve. Since it is rotatably supported by the carburetor main body, and one of the slot lever and the operating lever is provided with an operating pin that abuts against the other side edge, a small amount of rotation (angle) of the operating lever longer than the slot lever is supported. ), The throttle lever is smoothly rotated from the idle position to the fully open position via the operating pin. Since the turning angle of the operating lever is small, the bending of the inner cable connected to the operating lever at the insertion portion into the guide tube is slight. This means that the sliding resistance between the inner cable and the end of the guide tube is reduced compared to the conventional example, and the change in the rotational force applied from the inner cable to the operating lever is small, improving the smoothness of operation. It

The valve shaft connecting the throttle lever is supported substantially at the center of the carburetor body, while the operating lever is axially supported on the peripheral portion of the carburetor body and is arranged so as to overlap the upper side of the throttle lever. Therefore, the external dimensions of the entire carburetor are hardly affected, and the mounting arrangement on the engine is not hindered.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a valve operating mechanism of a carburetor according to the present invention, FIG. 2 is a plan view of the same, and FIG. 3 is a plan view of a throttle valve at a fully open position. 2: Main body, 5: Inner cable, 7: Guide tube, 21: Slot valve, 25: Valve shaft, 28: Control lever, 30: Slot lever, 3
1: swivel, 32: operating pin

Claims (2)

(57) [Claims] 1. An operation lever having a remote operation cable connected to an end thereof so as to be overlapped with an upper side of a throttle lever connected to a valve shaft of a throttle valve, can be pivoted to a carburetor main body by an axis parallel to the valve axis. A valve operating mechanism for a carburetor, characterized in that one of the throttle lever and the operating lever is supported by an operating pin that abuts the other side edge. 2. A carburetor valve according to claim 1, wherein the operating lever has a length longer than that of the slotter lever, and the rotation angle of the operating lever is smaller than that of the slotter lever. Operating mechanism.