JPS63186924A - Throttle link mechanism for carburetor - Google Patents

Abstract

PURPOSE:To always permit the smooth throttle operation by arranging a flat washer made of resin onto the both sides of an opener lever which is fitted onto a throttle valve shaft and turned, interlocked with the operation of a throttle opener so as to be externally fitted onto a stepped collar. CONSTITUTION:A fixed lever 5 onto which the top edge of a screw 6 for adjusting the idle opening degree and a throttle valve operating lever 7 interlocked with an accelerating pedal are fixed onto the throttle valve shaft 4 of a carburetor 1. All opener lever 16 is jointed through a collar 17 onto the throttle valve shaft 4, and an opener lever 18 which turns on the outer peripheral surface of a stepped collar 20 is installed, and the other edge of the opener lever 16 is connected with a throttle opener 11. A flat washer 22 made of resin is externally fitted in slidable ways for the outer peripheral surface of the small diameter part of the stepped collar 20 on the both sides of the opener lever 18, and a flat washer 23 is made of metal fitted outwardly onto the outside flat washer 22, and integrally fixed with the stepped collar 20 by a spring washer 24 and a nut 25.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a carburetor, and particularly to a carburetor side circuit connected to a throttle opener installed to prevent afterfire during deceleration and reduce exhaust gas. Improved durability of part of dynamic lever,
The present invention also relates to a throttle link mechanism suitable for preventing an increase in torque required for rotation of a throttle valve shaft.

[Prior art]

In a conventional throttle link mechanism, the carburetor-side rotating lever and the throttle opener are connected in an offset state due to installation restrictions, so when the throttle opener is activated, the rotating lever tilts, causing damage to the carburetor-side bearing. A thrust load is generated on the shaft, increasing frictional resistance and increasing shaft torque. Incidentally, related devices of this type include, for example, Utility Model Publications No. 1983-32831 and No. 53-3.
No. 8038 etc. are mentioned.

C Problems to be Solved by the Invention] In the throttle link mechanism of the carburetor according to the above-mentioned known technology, when the throttle opener lever receives rotational force, Although it receives a component force in the direction of falling, no special consideration has been given to the fact that rotation is subjected to frictional resistance due to the thrust force generated by this component force in the direction of falling.

The large frictional resistance described above not only increases the required operating force, but also causes problems such as failure of the throttle to return when the operating force disappears (for example, when the foot is released from the accelerator pedal). Furthermore, this friction accelerates wear.

It reduces durability. As a result, the throttle operation becomes less smooth after long-term use.

A specific phenomenon that the failure of the throttle return causes on the carburetor performance is that the engine speed fluctuation range due to throttle opener operation during deceleration becomes large. Figure 8 shows the relationship between the opener setting (throttle valve opening) and engine speed in an actual vehicle, and a 1 degree change in throttle valve opening is the fluctuation range of engine speed within the allowable range. I understand that there is something.

SUMMARY OF THE INVENTION An object of the present invention is to provide a throttle link mechanism that allows smooth throttle operation even after long-term use, and that can suppress engine speed fluctuations caused by throttle opener operation during deceleration within an allowable range. be.

[Means for solving problems]

The above object is achieved by attaching flat washers made of resin with a small coefficient of friction to both sides of the opener lever.

[Effect]

When the throttle opener is not operating, the resin flat washer is in a state where it can freely rotate on the carburetor bearing portion around which the opener rotates. When the opener is activated, a load in the thrust direction is applied to the bearing due to the tilting of the opener lever.
The flat washers are pressed against both sides of the bearing. However, since the opener lever is held from both sides through a resin with a small coefficient of friction, it has less sliding resistance and is much more durable than the conventional method in which metal-to-metal contacts directly and rotates. It is. Particularly, the effect is remarkable when the rotating part is used for a long period of time under environmental conditions in which salt water, mud, sand, etc. are mixed and adhered to the rotating part.

〔Example〕

1 to 3 show one embodiment of the present invention, in which FIG. 1 is a schematic front view, FIG. 2 is a side view, and FIG. 3 is an enlarged cross-sectional view of a main part.

1 is a carburetor main body, and 2 is a throttle valve provided in a carburetor intake pipe 3 and fixed to a throttle valve shaft 4.

Reference numeral 5 denotes a fixed lever integrated with the throttle valve shaft 4, and the tip of a screw 6 for adjusting the idle opening is in contact with the side surface of this lever. Reference numeral 7 denotes a throttle valve operating lever fixed to the throttle valve shaft 4, and is connected to an accelerator pedal via an accelerator cable. (Both not shown).

8 is a collar (A) that determines the mounting position of the operating lever 7 above.
Reference numeral 9 denotes a return spring for the operating lever 7, which is attached between the bottle 10 implanted in the carburetor main body 1 and the fixed lever 5.

Reference numeral 11 denotes a negative pressure responsive throttle opener that prevents the throttle valve 2 from suddenly closing for a certain period of time during deceleration in order to reduce after-fire and unburned gas (especially HC) emissions that occur during deceleration. be. The nipple 12 is communicated with the suction pipe or downstream of the throttle valve 2 through a rubber pipe or the like.

This throttle opener 11 is fixed to a bracket 14 by a nut (A113) and fixed to the carburetor main body 1 by a screw 15.16 is a collar (B).
) 17 is an opener lever (A) that is integrally connected to the throttle valve shaft 4. Reference numeral 18 is an opener lever (B) that rotates on the outer peripheral surface of the stepped collar 20, and has a bent portion at one end. 19, and this bent portion 19 is configured to come into contact with one end of the opener lever (A) 16 within a certain predetermined rotation angle range.

Further, the other end of the opener lever (A) 16 is connected to the throttle opener 11 by a rod 21. On both sides of this opener lever (B) 18, resin flat washers 22 are fitted so as to be able to slide freely on the outer peripheral surface of the small diameter part of the stepped collar 20 (see Fig. 3). with a flat washer.

0, which is integrally fixed to the stepped collar 20 by a spring washer and a nut 25, and is fixed to the throttle valve shaft 4.
Normally, to increase the rotational speed of the engine, the driver's seat depresses the accelerator pedal, which causes the throttle valve operating lever 7 to rotate in the direction of arrow L (see Figure 1), and the throttle valve shaft 4 to rotate in the direction of arrow R (see Fig. 1). (See Figure 2) to open the throttle valve 2. However, the throttle opener 11 is set so that it does not operate unless a negative pressure greater than that during idling is applied, so this operating state Now, opener lever (
B) 18 maintains the initial state, and during deceleration, a larger negative pressure is generated downstream of the intake pipe or throttle valve 2 than during idling, so through the nipple 12.

The negative pressure is transmitted to the throttle opener 11.

The rod 21 is pulled up and the opener lever (B) 18
rotates. When deceleration operation is performed to return the throttle valve 2 to the idle state, the bent portion 19 of the opener lever (B) 18 contacts one end of the opener lever (A) 16, and the throttle valve shaft 4 rotates in the direction of arrow R. do. Along with this operation, the throttle valve 2 is opened to the opener setting opening for a certain period of time until the negative pressure downstream of the intake pipe or the throttle valve returns to the idle negative pressure, and the after-fire and unburned gas generated during deceleration are removed. prevent the discharge of On the other hand, even during deceleration operation or gear change when the throttle valve 2 is opened beyond the set opening of the throttle opener, the negative pressure downstream of the suction pipe or the throttle valve becomes greater than the negative pressure at idle. .

The throttle opener 11 itself repeats the above operation.

In this way, the opener lever (B) 18
1, the number of operations is enormous. Note that the opener lever (B) 18 described above is subject to external constraints when installing the throttle opener 11.
(See Figure 3) Usually has a bend (the length of the lever arm). For this reason, the points of force application between the bearing rotation part and the rod 21 cannot be set on the same axis, and they are connected in a so-called offset state, which tends to cause them to fall during rotation, resulting in a lateral thrust load. In particular, the return spring 9 and the throttle opener 11 tend to generate frictional resistance in the bearing and increase the torque required to rotate the throttle valve shaft.
When the operating state is such that the balance of forces between the two and the opening lever (B) 18 is at its maximum, the thrust load acting on the opener lever (B) 18 is also at its maximum. In the conventional technology, when such an operating condition is continuously repeated for a long period of time, a throttle return failure occurs. However, in this embodiment, the opener lever (
B) Sandwich the flat washer 22 with the stepped collar 2.
It is externally fitted to 0. For this reason, opener lever (B) 1
8 does not directly touch the metal washer 23 or the side surface of the flange portion of the stepped collar 20. Therefore, large frictional resistance does not act on the rotation of the opener lever (B) 18, reducing wear. Progress is reduced.

In this example, the opener lever (B) 18 is sandwiched between a pair of flat washers 23 with a thickness of t, but as an embodiment different from this example, flat washers (not shown) with a thickness of t/N are used. It is also possible to arrange N sheets on both sides of the opener lever (B) 18. With this configuration, the anti-friction effect and wear resistance can be further improved.

FIG. 4 shows another embodiment of the present invention, and is a sectional view of a main part corresponding to FIG. 3 described above. Reference numeral 26 denotes a resin flat washer corresponding to the above 21, which is set at an angle of inclination of the opener lever (B) 18 so that the contact surfaces on both sides of the opener lever (B) 18 are always in contact with the outer peripheral edge of the flat washer 26. Accordingly, the outer diameter of the flat washer 26 is appropriately selected, and the cross-sectional shape of the flat washer 26 is configured to have roundness (so-called radius) at the corners of the outer peripheral surface. Therefore.

The sliding frictional resistance with the flat washer 26 when the opener lever (B) 18 is rotated can be minimized.

As a modification of this embodiment, the flat washer 23 may have a circular cross-sectional shape. Further, the flat washer can also be a C-shaped ring having a cut at one location in the circumferential direction.

Next, the durability test results of the example shown in FIG.

This will be explained in comparison with the durability test results of the conventional example.

FIG. 5 is a hysteresis chart of the conventional example, and FIG. 6 is a "valve opening-shaft torque" hysteresis chart of the embodiment. It is desirable that the difference in shaft torque between when the valve is open (towards the right in the diagram) and when the valve is closed (towards the left) is small.

In both FIGS. 5 and 6, the solid line is the hysteresis curve m before the durability test (abbreviated as "before durability" in the diagram), and the broken line is the hysteresis curve after the durability test (abbreviated as "after durability"). The structure of the conventional example described above corresponds to the structure shown in FIG. 3 with the flat washer 22 removed.

As is clear from comparing both figures, in this embodiment (Fig. 5), the shaft torque is small even before the durability test, and the difference (hysteresis) between when the valve is open and when the valve is closed is small. Moreover,
Even after the durability test, the increase in bisteresis in this example was significantly smaller (compared to the conventional example).Furthermore, the flat washers 22 and 26 showed a significantly lower increase in bisteresis (compared to the conventional example). It has been experimentally confirmed that by using fluororesin as the material, it can be used for a long period of time.

FIG. 7 shows that the carburetor main body 1 is heated under the condition that the room temperature rises and falls within a certain range of 130°C to +120°C for a certain period of time, in accordance with the durability of the repeated operation of the throttle valve.
Figure 3 shows the changes in the gap δ and throttle valve opening before and after a combined durability test using a bench testing machine when vibrations approximately equivalent to those of an actual vehicle are applied to the vehicle. If the gap δ, which shows the change from before the durability test to after the durability test, is small, the sliding resistance when the opener lever is activated will be large.
Shaft torque increases. On the other hand, if the gap δ is large, the angle of inclination of the opener lever (B) 18 becomes large, making it impossible to secure a predetermined opener setting. Therefore, it is necessary to minimize the change in the gap δ before and after durability. 7th
In the figure, if the thickness of one sheet of the flat washers 22 and 26 before durability test is 1.0 + a, then after the durability test, the thickness will be reduced to about 1/2, or 0.5 m. Therefore, the flat washers 22 and 26 are attached to the opener lever (B).
Since one sheet is interposed on each side of 18, the gap δ is
becomes 1.0 wealth. This gap δ=1.01 determines the inclination angle of the opener lever (B), and the initial thickness of the so-called resin flat washer, which causes a 1 degree change in the throttle valve opening, is 1.
If m, then the throttle valve opening will change by 1 degree under the above-mentioned durability conditions. Under the above durability conditions, the flat washers 22 and 26
The change in thickness (becoming thinner) is due to the deterioration of the resin material due to cold and heat, as well as the swinging of the opener lever (B) due to vibration and the action of the thrust load when the opener is operated.

〔Effect of the invention〕

As described above, according to the present invention, the frictional resistance between the throttle valve shaft of the carburetor and the bearing part caused by the tilting of the opener lever, which freely rotates in conjunction with the operation of the throttle opener, is reduced as much as possible. It is possible to prevent an increase in shaft torque with a simple configuration, ensuring smooth throttle operation even after long-term use, and keeping engine speed fluctuations due to throttle opener operation during deceleration operation within an allowable range. It becomes possible to obtain a carburetor having a throttle link mechanism that is extremely effective in practice.

[Brief explanation of the drawing]

FIG. 1 is a schematic front view of an embodiment of the present invention, FIG. 2 is a side view of the embodiment, and FIG. 3 is a sectional view of the same essential parts. FIG. 4 shows another embodiment of the present invention, and is a sectional view of a main part corresponding to FIG. 3. 5 and 6 are charts showing the results of the throttle valve operation durability test for the conventional example and the above-mentioned embodiment. FIG. 5 shows the test results for the conventional example, and FIG. 6 shows the test results for the present example. FIG. 7 is a chart showing the relationship between washer thickness and throttle valve opening before and after the combined action durability test, and FIG. 8 is a chart showing the relationship between throttle valve opening and engine speed. DESCRIPTION OF SYMBOLS 1... Carburetor body, 2... Throttle valve, 3... Carburetor intake cylinder, 4... Throttle valve shaft, 5... Fixed lever, 6...
Screw, 7... Throttle valve operating lever, 8... Collar (
A), 9...Return spring, 10...Bin, 11
...Throttle oven, 12...Nipple, 13
... Nut (A), 14... Bracket, 15...
・Screw, 16...Opener lever (A), 17.
...Color (B), 18...Opener lever (B),
19...Bending portion, 20...Stepped collar, 21...
Rod, 22.26...Resin flat washer, 23...
・Metal flat washer, 24...spring washer,
25...Natsuto.

Claims (1)

[Scope of Claims] 1. A stepped collar is externally fitted onto the throttle valve shaft of the carburetor, and a pair of opener levers is configured, and one of the pair of opener levers is aligned with the stepped collar and attached to the throttle valve shaft. In a throttle link mechanism having a structure in which the other of the pair of opener levers is fitted externally to the stepped collar, a plurality of resin flat washers are fitted externally to the stepped collar with the other opener lever in between. A throttle link mechanism for a carburetor, which is characterized by: 2. The throttle link mechanism for a carburetor according to claim 1, wherein the plurality of resin flat washers are made of fluororesin. 3. The number of the plurality of resin flat washers is four or more, and two or more are arranged on each side of the other opener lever, as set forth in claim 1. carburetor throttle linkage. 4. The throttle link mechanism for a carburetor as set forth in claim 1, wherein the cross-sectional shape of the plurality of flat resin washers is rounded at the corners on the outer periphery thereof. .