JPS603438A - Fuel supply system - Google Patents

Abstract

PURPOSE:To smoothly operate a coiled spring which returns the throttle valve of a carbureter and restrain variation of the characteristics of the spring by coating the surface thereof with antifriction material. CONSTITUTION:A coiled spring 11 which returns the throttle valve 7 of a carbureter has the surface thereof coated with antifriction material, such as ethylene tetrafluoride resin or so, whereby reducing wear resulting from contact of the spring and restraining variation in the characteristics thereof.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a fuel supply system (carburetor) for an automobile, and particularly relates to an improvement of a fuel supply system having a coil spring for returning a throttle valve. .

[Background of the invention]

Figure 1 can be seen, for example, in Japanese Patent Publication No. 54-99832.
FIG. Inside the intake cylinder 6 of the main body 1 of the fuel supply device, there is a choke valve 2 attached to a choke shaft 3 from above, a venturi 4 with a nozzle 5 protruding from the opening, and a throttle valve attached to the valve shaft 8. A throttle valve 7 is installed. In addition, the stopper lever 9 attached to the outside part of the throttle valve shaft 80 main body 1
A coil spring 11, which is the object of the present invention, is interposed between the collar 103 that fixes the throttle lever 12 and the collar 10b that fixes the throttle lever 12.

The right end of this coil spring 11 is wound around a stopper bin 13 installed on the main body 1, and the other end is locked to the throttle lever 12, which applies a weak force to the throttle valve shaft 8 in the direction of closing the opening of the throttle valve 7. It is working. The minimum (idle link) opening degree of the throttle valve 7 at this time is determined by the tip of the stopper lever 9 coming into contact with the stopper 14 fixed to the main body 1.

That is, in this fuel supply device, the coil spring 11
is used as a screw spring, and when the opening degree of the throttle valve 7 is increased, the restoring force is used to return the throttle valve 7 to its original position.

Note that the throttle lever 12 is connected to a pedal via an intermediate connector.

In the fuel supply device configured in this way, the means for generating the restoring force of the throttle valve 7 can be made compact by using the coil spring 11, but the space for installing this screw spring is narrow and the line The gap between them is very small.

However, since the wires are twisted during operation, the gap is further reduced, and the wires come into contact with each other and are susceptible to wear.

Therefore, when used for a long period of time, there is a fear that the wires will wear out and the spring characteristics will change, friction will occur and the valve will get stuck, and the reproducibility of the operation will not be maintained and the control of the opening of the throttle valve will become inaccurate. Further, such unsmooth operation is transmitted to the driver and gives a feeling of discomfort, and furthermore, if rust occurs in the worn parts, the above-mentioned tendency is doubled.

[Purpose of the invention]

The present invention solves the above-mentioned drawbacks of the prior art and provides a fuel supply device that operates smoothly and whose spring characteristics do not change over a long period of time by adding simple processing to a coil spring that is a threaded spring. With the goal.

[Summary of the invention]

A feature of the present invention is that the surface of the coil spring is coated with a wear-resistant anti-friction coating.

[Embodiments of the invention]

2 and 3 are perspective views of a coil spring whose surface is coated with anti-friction properties of the present invention, and FIG. 4 is an enlarged sectional view of the coil spring. In FIG. 2, the winding portion at the right end is a portion to be wound around the stopper pin 13 of FIG. Please note that FIG. 3 shows the case of a coil spring 11 used in a relatively small fuel supply device.

Spring steel wire 16 forming these coil springs 11
is coated with Antifriction 15.

There are examples of conventional wire rods being coated with nylon, etc.
This is for the purpose of preventing rust when constantly exposed to outside air or rain. However, in the case of this embodiment, tetrafluoroethylene resin (trade name of DuPont, USA) is sprayed and coated to a thickness of 3 to 100 μm. Although this coil spring 11 is wound as shown in FIG. 2, it can enter through the gap and be tightly attached to the entire circumference. Note that if the coil spring 11 is pulled and slightly expanded, uniform coating can be more easily achieved, and a gap between the lines of about 1 m is sufficient.

Since the above-mentioned nylon resin is generally coated on the wire by a dipping method, it is difficult to coat the wire with a uniform thin layer and it is susceptible to thermal changes. therefore,
Nylon resin materials are unsuitable for applications such as automobiles, which operate at temperatures ranging from a low temperature of -4 Orr to a high temperature of +150 C. That is, when the temperature reaches high temperatures, there is a risk that the wire will soften, flow, and warp, increasing the friction between the wires.

FIG. 5 is a diagram showing the relationship between the opening degree of the throttle valve and the torque of the throttle valve shaft when a coil spring made of a conventional material is used. The solid line A shows the operation at the initial stage of use, and the fine broken line B shows the operation after long-term use. In other words, the change is smooth at the beginning of use, but after long-term use, the difference between the torque in the opening direction and the closing direction of the throttle valve 7 increases and the change becomes unsmooth υ, and this feeling causes discomfort to the driver. There was also concern about spring switching.

As mentioned above, the installation location of the coil spring 11 is narrow and the spring load is carefully controlled so that when the driver stops accelerator operation and takes his/her foot off the pedal, the throttle valve 7 smoothly returns to the idle opening position. .

In addition, increasing the spring load as described above necessitates the use of thicker wires to avoid exceeding the allowable stress range of the material, which reduces the gap between the wires and makes it easier for them to come into contact with each other due to car vibrations, etc. It had become.

Figure 6 is a characteristic diagram of a coil spring treated with anti-friction material as shown in Figure 4. As in Figure 5, the solid line A is the initial use, and the broken line B is the characteristic after long-term use. It is.

In this case, there is almost no difference in characteristics, indicating that suitable operation can be achieved for a long period of time.

The coil spring for controlling the throttle valve of this example has its surface coated with a spray of polytetrafluoroethylene resin after winding and shaping, so that even if contact between the υ wires occurs due to vibration, the characteristics due to wear will not be affected. It has the effect of operating suitably for a long period of time without any change.

In the above example, the properties were maintained for a long period of time by resin coating, but the following experiments were also carried out.

In other words, this is a conventionally known anti-corrosion treatment method in which an aqueous solution containing metallic zinc and chromic acid as main components and an aqueous solution of glycol are applied to the surface of the wire and then baked in a high-temperature furnace. This has a rust-preventing effect, but when applied to springs, the surface becomes rough and the driver feels an increased sense of unsmoothness, so no desirable results were obtained.

〔Effect of the invention〕

The coil spring for controlling the throttle valve of the fuel supply device of the present invention has the effect that its characteristics can be greatly improved by adding a simple process of performing fluoroethylene treatment after molding.

[Brief explanation of the drawing]

Figure 1 is a vertical sectional view of a fuel supply system for an automobile engine.
Figures 2 and 3 are perspective views of a coil spring coated with the anti-friction surface of the present invention, Figure 4 is an enlarged cross-sectional view of the coil spring, and Figure 5 is a coil spring using a conventional material. FIG. 6 is a characteristic diagram of the treated coil spring as shown in FIG. 4. 1... Main body, 6... Intake cylinder, 7... Throttle valve, 8...
... Throttle valve shaft, 9... Stopper lever, 10... Collar, 11... Coil spring, 12... Throttle lever, 13... Stopper pin, 14... Stopper, 1-5・・・Reduced foil drawing 5 drawing house drawing 6 drawing

Claims (1)

[Claims] In a fuel supply device in which a coil spring for restoring the state of a throttle valve is wound around a part of the throttle valve shaft outside the main body, the surface of the coil spring is coated with a wear-resistant material. A fuel supply device characterized by being coated with anti-friction 4X. 2. The fuel supply device according to claim 1, wherein the anti-friction U is a tetrafluoroethylene resin.