JPS6327075Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a throttle switch that detects the closed position of a throttle valve that controls the intake air amount of an internal combustion engine.

[Prior art]

First, an example of the operation of this type of throttle switch will be explained with reference to FIG. FIG. 1 is a schematic diagram of the intake system of an internal combustion engine. In FIG. 1, 1 is the internal combustion engine main body, and 2 is a carburetor that supplies the internal combustion engine main body 1 with an air-fuel mixture according to the operating conditions of the internal combustion engine main body 1. ,3
is a throttle valve attached to the carburetor 2, which controls the intake air amount of the internal combustion engine main body 1. 4 is an arm fixed to the rotating shaft of the throttle valve 3, and moves with the throttle valve 3. 5 is due to the movement of arm 4.
With a throttle switch that turns ON and OFF, when the throttle valve 3 is in the closed position, the movable shaft of the throttle switch 5 is pushed by the arm fixed to the throttle valve 3, and the electric contact built into the throttle switch 5 is turned ON. Become. This electrical signal is transmitted to a control device of the internal combustion engine. Furthermore, the electrical contacts of the throttle switch 5 also serve as a stopper for determining the closed position of the throttle valve 3.
In order to fulfill the role of the throttle switch 3, the hysteresis phenomenon of the electrical contacts is eliminated and the electrical contacts are in contact with each other.

In the intake system of the internal combustion engine configured as described above, the throttle valve 3 operates in various ways depending on the operating state of the internal combustion engine main body 1. For example, the throttle valve 3 is operated from a fully open position to a closed position all at once. Alternatively, it opens slightly from the closed position and slowly moves to the closed position. Therefore, due to the operation of the throttle valve 3, the throttle valve 3
When the throttle valve 3 is suddenly moved from the fully open position to the closed position, a strong impact force is applied to the electrical contacts of the throttle switch 5, which is a stopper.
In addition, when the throttle valve 3 opens slightly from the closed position and slowly moves to the closed position, various forces are applied to the electrical contacts, such as only a weak force with no impact force, and each time the contact pressure of the electrical contacts are also different.

As mentioned above, the material of the electrical contacts of the throttle switch 5 is extremely hard and will not wear out against strong impact forces, and even if the contact pressure of the electrical contacts is small due to the weak force, the electrical contacts will be sufficiently conductive. Strict conditions are required. However, as electrical contact materials, materials such as tungsten, which are hard but do not conduct if the contact pressure of the electrical contact is small, or precious metals, which conduct well even if the contact pressure of the electrical contact is small, but are soft and cannot be used as electrical contacts. There are only those with contradictory characteristics, such as the fact that they wear out when impact force is applied to them. Therefore, there is no current contact material that fully satisfies the conditions required for the electrical contact of the throttle switch 5.

[Summary of the idea]

In the present invention, one of the electric contacts built in the throttle switch 5 is fixed to a diaphragm to make it a movable contact, and when the diaphragm is operated, a strong force is applied to the electric contact of the throttle switch 5 by the operation of the throttle 3. Even if the electrical contacts are made of soft precious metals, the electrical contacts will not wear out, and the throttle switch 5
The present invention provides a throttle switch 5 for an internal combustion engine that has improved service life and reliability.

[Example of idea]

An embodiment of the present invention will be described below with reference to FIG. FIG. 2 is a diagram of the internal structure of the throttle switch. In FIG. 2, reference numeral 6 denotes a metal case, which has a threaded portion that serves as a means for attaching the throttle switch. This threaded portion also serves as an adjustment screw for the throttle valve 3. Reference numeral 7 designates a movable shaft, one end of which serves as a contact surface for the arm 4, and the other end located opposite to the above is an electrical contact.
It serves as a movable contact 8. 9 and 10 are metal supports fixed to the movable shaft 7. A diaphragm 11 is made of a thin film of rubber or the like, and is fixed to the movable shaft 7 by supports 9 and 10. 12 is a spring for returning the movable shaft 7, 13 is a terminal, and 14 is a fixed contact fixed to the terminal 13. 15 is a contact surface of the fixed contact 14, with which the movable contact 8 comes into contact. 16 is terminal 1
4 is fixed to the terminal block, and electrically insulates the terminal 14. A guide 17 for the movable contact 8 surrounds the movable contact 8 and the fixed contact 14.
A metal cover 18 fixes the diaphragm 10 to the joint surface with the metal case 6, and forms a diaphragm chamber 20 closed by the diaphragm 6. Further, the metal cover 18 is electrically connected to the metal case 6. An orifice 19 adjusts the amount of air discharged from the diaphragm chamber 20. A check valve 21 controls opening and closing of an air hole 22 through which air flows into the diaphragm chamber 20. The electric circuit of the throttle switch, which is an embodiment of the present invention, shown in FIG.
⇒ Metal cover 18 ⇒ Metal case 6.

In the throttle switch configured as described above, when a strong impact force is applied to the movable shaft 7, the movable shaft 7 tries to operate, but the diaphragm 10 is fixed to the movable shaft 7, and the diaphragm 1
1, the pressure in the diaphragm chamber 20 increases in response to the movement of the movable shaft 7, thereby preventing rapid movement of the movable shaft 7. Therefore, if the pressure in the diaphragm chamber 20 remains elevated, the movable contact 8 will not come into contact with the contact surface 15 of the fixed contact 14, so the pressure in the diaphragm chamber 20 is gradually discharged from the orifice 19. Therefore, as the pressure in the diaphragm chamber 20 decreases, the movable shaft 7 gradually moves, the movable contact 8 comes into soft contact with the fixed contact 14, and the impact force generated at the contact part is eliminated. Conversely, when the movable contact 8 contacts the fixed contact 14 and the electrical contact returns from the ON state to the OFF state, the movable shaft 7
It is pushed back, but here the orifice 19
If only the amount of air flowing into the diaphragm chamber 20
becomes a negative pressure, and the operation of the movable shaft 7 is inhibited, so that the movable shaft 7 does not operate sharply. Therefore, the check valve 20 is opened and a large amount of air flows into the diaphragm chamber 20 through the air hole 22, so that the operation of the movable shaft 7 is not inhibited.

As mentioned above, the throttle switch of this invention is
In order to detect the exact position of the throttle valve and to attenuate the strong impact force applied to the electrical contacts of the throttle switch by the arm fixed to the throttle valve, an inexpensive component called a diaphragm is used. Because the force is attenuated, it is possible to use softer precious metal electrical contacts, improving the life and reliability of the throttle switch.

In the above embodiment, the atmosphere was used as a medium for operating the diaphragm, but if the orifice and air hole are communicated with a chamber other than the diaphragm chamber,
The same effect can be obtained with fluids other than air, such as oil.

[Effect of idea]

As mentioned above, the throttle switch of this invention is
It has become possible to significantly improve the lifespan and reliability of electrical contacts with an inexpensive mechanism.

[Brief explanation of the drawing]

FIG. 1 is a schematic view of an intake system of an internal combustion engine showing an example of the use of a throttle switch, and FIG. 2 is a sectional view showing an embodiment of the present invention. In the figure, 1 is the internal combustion engine body, 3 is the throttle valve,
4 is an arm, 5 is a throttle switch, 6 is a metal case, 7 is a movable shaft, 8 is a movable contact, 11 is a diaphragm, 14 is a fixed contact, 18 is a metal cover,
19 is an orifice, and 21 is a check valve.

Claims (1)

[Scope of utility model registration request] An electric contact is arranged between an arm fixed to the rotating shaft of a throttle valve that controls the intake air amount of an internal combustion engine, and a throttle adjustment screw that faces the arm and adjusts the closed position of the throttle valve. In the configured throttle switch, the electric contacts are composed of a fixed contact fixed to the throttle adjustment screw and a movable contact fixed to the diaphragm and moved by the arm, and the electric contact is fixed to the diaphragm and moved by the arm. A throttle switch for an internal combustion engine, characterized by having a hole through which fluid filled in the chamber flows.