JPS5968533A - Throttle valve opening and closing apparatus for carburetor - Google Patents

Abstract

PURPOSE:To prevent an excessive force acting upon an operating shaft by providing a pulley on the throttle valve operating shaft, a throttle valve opening and closure apparatus which is operated by an opening wire and a closing wire, and a spring member in the middle of either one of an inner wire or an outer wire which constitute the closing wire. CONSTITUTION:A pulley 2 is provided on an operating shaft 1 of a throttle valve, and an opening wire 3 and a closing wire 4 are connected thereto. The respective wires 3, 4 comprise an inner wire A and an outer cable B. A stopper 6 to regulate the rotation limit of the operating shaft to the throttle valve closure side is provided in a position opposite to a protrusion 2a of the pulley 2. As a spring 7 is installed in the middle of the inner wire A of the closing wire, even if the closing wire is operated with a large force, an excessive external force does not act upon the pulley 2 and operating shaft 1, accordingly deformation, damages etc. thereto may be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a throttle valve opening/closing device particularly suitable for a carburetor for a motorcycle. This relates to a so-called forced opening/closing operation mechanism in which the operator is connected to an opening wire and a closing wire, and both opening and closing operations of the throttle valve are performed by the wire. The purpose is to prevent excessive valve closing operation force from being applied.

Conventionally, so-called forced opening/closing operation mechanisms have been used in high-performance motorcycles, but when the throttle valve is suddenly closed to decelerate while driving, excessive valve closing force is applied to the throttle valve's operating shaft. This caused the idle link speed to become unstable and the operation to be less agile.

This invention was made to eliminate such problems,
The feature is that a spring member is interposed in the middle of the operating wire that opens and closes the throttle valve. This will be explained below with reference to illustrated embodiments. In the figure, 1 is an operating shaft of a throttle valve (not shown), to which a pulley 2 is attached. Pulley 2
An open wire 3 and a close wire 4 are connected to an operator such as an accelerator grip (not shown).

Each wire 3.4 is a so-called Bowden wire consisting of an inner wire A made of twisted thin copper wires and a flexible outer cable B surrounding it. It is connected to the pulley 2 by a drum-shaped stopper 5. 6 is an idle link speed adjustment screw that regulates the rotation limit of the operating shaft toward the throttle valve closing side, and pulley 2
It supports the upper protrusion 2a.

In the example shown in FIG. 1, a coil spring as a spring member 7 is interposed in the middle of the inner wire A, and when the closing wire 4 is closed with a force greater than expected, it stretches and the operating force is Make sure it does not reach pulley 2.

In FIGS. 2 and 3, a coil spring serving as a spring member γ is interposed between an end fitting of an outer cable B and a support member 8 that supports it. That is, the end support member B
An arm 11 is rotatably supported by a pivot [111119] on the support frame of the barrel carburetor, and a spring member 7 is interposed between the arm 11 and one end of the arm 11 to spring the arm 11 clockwise. Furthermore, by the engagement between the elongated hole 8a formed in the end support member 8 and the pin 11a provided in the arm 11, the rotation range is restricted and the attachment of the closing wire 4 to the arm 11 is facilitated. The end of the outer cable B is screwed into the other end of the arm 11 and fixed to the oak 11b.

In addition, in anticipation of the case where the regulation by the spring member 7 is not sufficient, a means is provided for regulating the movement of the inner wire A with respect to the outer cable B. That is, in FIGS. 1 and 2, a stopper 12 is fixed in the middle of the inner wire A, and when it hits the end fitting of the outer cable B, further movement is restricted. Further, in the example shown in FIG. 3, the end fitting of the outer cable B is formed to be a little long, and a protrusion 2b is provided on the pulley 2 located in front of the end fitting so that the protrusion 2b can be pushed out.

Next, the operation of the embodiment will be explained. When an operator such as an accelerator grip is operated to increase the output of the engine, the opening wire 3 connected thereto is pulled, causing the pulley 2 to rotate clockwise and open the throttle valve. When reducing the output, the operator is operated in the opposite direction to pull the closing wire 4 and rotate the pulley 2 counterclockwise. When the operator is strongly operated, the protrusion 2a of the pulley 2 hits the idle speed adjusting screw 6 and stops. This position is normally the minimum opening of the throttle valve, that is, the throttle valve opening that defines the idle speed of the engine, and can be adjusted high or low by the adjusting screw 6.

In this throttle valve closing operation, if the closing operation is performed with excessive force, in the case of the embodiment shown in FIG. Since the coil spring 7 does not rotate, the coil spring serving as the spring member 7 expands, and only a relatively weak force set by the spring member 7 acts on the operating shaft 1, thereby preventing its deformation. In the case of the embodiments shown in FIGS. 2 and 3,
When the protrusion 2a on the pulley 2 hits the idling speed adjustment screw 6, the arm 11 is moved by the reaction force of the force pulling the closing wire 4.
rotates counterclockwise against the spring member 7, and a relatively weak force set by the spring member 1 acts on the operating shaft 1 as in the previous example.

Moreover, when the closing wire 4 is pulled even more strongly, FIG.
In the example shown in FIG. 2, the stopper 12 fixed in the middle of the inner wire A hits the end fitting of the outer cable B and does not move any further. In the example shown in FIG. 3, the end fitting of the outer cable B, which is formed to be rather long, hits the protrusion 2b of the pulley 2 located in front of it and cannot move any further.

As described above, this invention provides a vaporizer in which a pulley is provided on the operating shaft of a throttle valve, an opening wire and a closing wire are connected to the pulley, and a stopper is provided for regulating the limit of rotation of the operating shaft toward the closing side of the throttle valve. In the device, the closing wire is composed of an inner wire and an outer cable surrounding it, and at least one of the inner wire and the outer cable has a spring member interposed therebetween. Even if a valve operating force is applied, it does not strongly act on the pulley provided on the operating shaft of the throttle valve. Therefore, there is an effect that no excessive external force is applied to the operating shaft of the throttle valve, and no deformation or other trouble occurs.

In addition, as shown in the examples, a method in which a spring member is interposed in the middle of the inner wire does not make it easy to set and maintain the spring constant, but the structure is simple, and a method in which the spring member is interposed in the middle of the outer cable Now, the structure is getting more complicated.
Since the spring member can be easily set, it is highly practical.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a front view showing the main parts of the forced opening/closing mechanism of the throttle valve, FIG. 2 is a similar front view showing a modification thereof, and FIG. The figure is a similar front view showing still another modification. 1... Throttle valve operating shaft, 2... Pulley, 3...
...Opening wire, 4...Closing wire, 6...Adjusting screw forming a stopper, 7...Spring member, 8...
- Support member, 11...arm, 12...stopper, A...inner wire, B...outer cable. Patent applicant Yamano Motor Co., Ltd.

Claims (5)

[Claims] (1) In a carburetor, a pulley is provided on the operating shaft of the throttle valve, an opening wire and a closing wire are connected to the pulley, and a stopper is provided to restrict the rotation limit of the operating shaft toward the closing side of the throttle valve.
A throttle valve opening/closing device in which the closing wire is composed of an inner wire and an outer cable surrounding the inner wire, and a spring member is interposed in the middle of at least one of the inner wire and the outer cable. (2) The throttle valve opening/closing device according to claim 1, wherein the spring member is a coil spring provided in the middle of the inner wire constituting the closing wire. (3) The throttle valve opening/closing device according to claim 1, wherein the spring member is a spring provided between an outer cable constituting the closing wire and a support member that immovably supports the outer cable. (4) The throttle valve opening/closing device according to claim 3, wherein the outer cable is provided with a stopper for regulating its forward end. (5) The throttle valve opening/closing device according to claim 1, wherein the inner wire constituting the wire is provided with a stopper that comes into contact with the outer cable when the inner wire is pulled beyond a predetermined limit.