JPH0159415B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an idle opening setting mechanism for a throttle valve of an automobile carburetor, and more particularly to a tamper-proof structure that limits the readjustment range of the idle opening.

In the carburetor installed in a gasoline engine, the throttle valve opening is set when the engine is idling, but the idle opening set by the manufacturer is the idle opening after the engine has operated to a certain extent and the friction in the engine rotation mechanism has decreased. Since the opening degree is somewhat different from the idle opening degree, it is now possible to reset the idle opening degree. That is,
Automobile repair shops and the like adjust the position of the idle adjustment screw on new cars that have been used for a certain period of time to make them comply with exhaust gas regulations and to optimize the fuel consumption rate and idling operating conditions.

However, since conventional idle adjustment screws can also be adjusted by the user, manufacturers are now required to provide a way to prevent this. In other words, the idle adjustment screw cannot be adjusted beyond the minimum necessary amount. In order to make adjustments impossible for the user, conventional methods have been to fix the adjustment screws or to completely shield them. Such means have the disadvantage that they are complex in structure, cumbersome to handle, or incomplete.

The purpose of the present invention is to provide a throttle valve idle opening setting mechanism that satisfies the tamper-proof function with a relatively simple configuration, and uses a rib that protrudes from the carburetor body and is provided with a screw hole, and a coil spring. an auxiliary adjustment screw that is screwed into the screw hole and has a driver groove at one end, a continuous large-diameter portion in the head and a tip at the other end; and one end fixed to the throttle valve shaft. The adjustment lever is screwed into a screw hole provided at the other end of the adjustment lever, and the large diameter portion at one end is located within a shielding wall provided around the screw hole of the rib. A main adjusting screw has a head that faces the tip of the adjusting screw and has a driver groove at the other end and is sealed with a blind plug, and a large diameter portion of the auxiliary adjusting screw has a head that has a driver groove at the other end. It is characterized in that the tip is at an idle opening at a position where it comes into contact with a rib and the tip protrudes from the rib.

The figure is a sectional view of a main part of a vaporizer that is an embodiment of the present invention. A throttle valve 3 is installed in the feed cylinder 2 of the main body 1 of the carburetor, and an adjustment lever 4 and an operating lever 5 are fixed to the part of the throttle valve shaft to which the throttle valve 3 is attached outside the carburetor. . Further, a rib 7 is projected from the outer surface of the carburetor main body 1, and the left side of this rib 7 is seated to form a shielding wall 8, and a screw hole is provided horizontally in the center of the shielding wall 8, and a coil spring 11 is inserted through the rib 7. The auxiliary adjustment screw 9 is screwed together. On the other hand, a screw hole is provided in the upper part of the adjustment lever in a direction that matches the screw hole of the rib 7, and a large diameter portion 1 is provided at the tip of the screw hole.
A main adjustment screw 12 formed with a number 3 is screwed into the main adjustment screw 12, and the head having a driver groove is sealed with a blind plug 14.

The operation of the throttle valve idle opening degree setting mechanism configured as described above will be explained next. Since the operating lever 5 that interlocks with the throttle valve 3 is constantly pulled by the return spring 6, the throttle valve 3 receives a force in the direction of reducing its opening. Since it is in contact with the tip 15, the minimum opening degree of the throttle valve 3, that is, the idle opening degree of the throttle valve is set.

In the figure, the length of the screw hole of the rib 7 is T,
The end face of this rib 7 and the large diameter portion 10 of the auxiliary adjustment screw 9
The distance from the end face of the rib 7 to the end face is l ₁ , and the dimension in which the tip 15 of the auxiliary adjustment screw 9 protrudes from the end face on the opposite side of the rib 7 is
If l ₂ , by rotating the auxiliary adjustment screw 9 in the forward direction, the throttle valve opening can be increased by an amount corresponding to l ₁ , and by rotating the auxiliary adjustment screw 9 in the reverse direction, it can be increased to l ₂ . The throttle valve opening can be reduced by a corresponding amount.

The adjustment order of this idle opening setting mechanism will be explained. First, prior to adjustment, the auxiliary adjustment screw 9 is screwed in until the large diameter portion 10 contacts the rib 7 (l ₁ =0). At this time, the tip 15 of the threaded portion of the auxiliary adjustment screw 9 protrudes from the opposite end surface of the rib 7 by l ₁ +l ₂ . Next, the main adjusting screw 12 is rotated with the large diameter portion 13 of the auxiliary adjusting screw 9 in contact with the main adjusting screw 12 to set the state of the throttle valve 3 to a predetermined idle opening degree. Then blind plug 1
4 and finish the settings at the manufacturer.

When the friction of a newly adjusted car decreases after a certain period of time, the auxiliary adjustment screw 9 is rotated in the opposite direction, and the throttle valve idle opening degree is further reduced. The figure shows the situation at this time, and a gap l ₁ will be created, but in reality, this l ₁ is smaller than l ₂ , so even if the user screws in the auxiliary adjustment screw 9 again, the characteristics will not change. There will be no major disturbance.
On the other hand, the larger dimension _l2 can be made zero by rotating the auxiliary adjustment screw 9 in the opposite direction, but this does not pose a problem since it is in the direction of reducing the opening degree of the throttle valve.

The idle opening setting mechanism of this embodiment is installed by screwing a main adjustment screw whose tip is in contact with the tip of an auxiliary adjustment screw screwed into the rim into an adjustment lever fixed to the throttle valve shaft. After the adjustment, the following effects can be obtained by sealing the screw hole into which the main adjustment screw is screwed with a blind plug.

(1) A mechanism that mainly makes it possible to change the direction of reducing the idle opening of the throttle valve by making a relatively simple improvement by providing a screw hole in the conventional adjustment lever and attaching the main adjustment screw. It is possible to restrict arbitrary adjustments by the user.

(2) Not only is the head of the main adjustment screw with the driver groove covered with a blind plug, but the tip, including the large diameter part, is covered with a shielding wall. It makes it impossible for the user to make arbitrary adjustments such as inserting a tool between the adjustment lever and rotating the large diameter part, and the contact area between the large diameter part of the main adjustment screw and the tip of the auxiliary adjustment screw is shielded. Since it is covered by the wall, it is impossible for the user to insert a spacer into this contact portion to increase the opening degree of the throttle valve, and the tamper-proof function can be satisfied.

(3) In this way, the user is prevented from arbitrarily changing the idle opening of the throttle valve, so the goal of purifying exhaust gas is achieved, and it is also possible to obtain suitable idle speed and fuel savings. .

In the above example, when the manufacturer adjusts l ₁
The position of the main adjustment screw 12 was adjusted to _the optimum state with When there is slight wear due to contact, the l ₁ gap is no longer necessary. In reality, the situation is often close to this.

The throttle valve idle opening setting mechanism of the present invention is relatively simple and has the effect of preventing arbitrary changes by the user.

[Brief explanation of drawings]

The drawing is a sectional view of a main part of a carburetor that is an embodiment of the present invention. 1... Main body, 2... Supply cylinder, 3... Throttle valve, 4
... Adjustment lever, 5 ... Operation lever, 6 ... Return spring, 7 ... Rib, 8 ... Shielding wall, 9 ... Auxiliary adjustment screw, 10, 13 ... Large diameter part, 11 ... Coil spring, 12...Main adjustment screw, 14...Blind plug, 15
...Tip.

Claims (1)

[Claims] 1. A rib that protrudes from the carburetor body and is provided with a screw hole, and a large diameter portion that is screwed into the screw hole via a coil spring and continues to the head that has a driver groove at one end, and a tip portion at the other end. An auxiliary adjustment screw provided with an adjustment lever, an adjustment lever whose one end is fixed to the throttle valve shaft, and a screw hole provided at the other end of the adjustment lever, and the large diameter part of the one end is screwed into the screw hole provided at the other end of the adjustment lever. The head of the auxiliary adjustment screw, which faces the tip of the auxiliary adjustment screw and has a driver groove at the other end, is sealed with a blind plug within a shielding wall provided around the screw hole. a manual adjustment screw, and the throttle valve has an idle opening at a position where the large diameter portion of the auxiliary adjustment screw contacts the rib and the tip protrudes from the rib. Idle opening setting mechanism.