JPH02177225A - Throttle switch - Google Patents

Abstract

PURPOSE:To obtain a switching action with high answerability and stability and without causing chattering by placing an end of a shaft such that it is opposed to a throttle lever and mounting the extended portion of a housing on a cylindrical body. CONSTITUTION:When a ring projection 9a of a pressure sensitive conductor 9 is pushed to a fixed contact 5 in a throttle switch 1, the resistance value of a conductor 9 becomes least, and when the top 3a of a shaft 3 is pushed in the direction of a sliding element 8 and against a compression spring 10, the sliding element 8 slides inside a guide cylinder 7 and a pushing force of the contact 5 of the projection 9a decreases, the value of resistance of the conductor 9 increases, and when the top 3a ranks with the end face of the extended portion 2b, the value of resistance becomes most. When this switch 1 is mounted to a carburetor, an shaft 21 is made to clockwise move and a throttle valve 22 circularly moves in the opening direction, a throttle lever 23 moves in the direction to segregate from the top 3a. Thereby, the resistance value of the conductor 9 decreases and reaches a prescribed one; thereupon, a current flows between lead wires 11a and 11b.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a throttle switch that detects the fully closed position of a throttle valve of an internal combustion engine, and particularly to a throttle switch that has a throttle adjustment function that adjusts the throttle valve opening. Related.

[Prior Art] Throttle switches whose contacts open and close according to the operation of the throttle valve have traditionally been used mainly for the purpose of detecting the fully closed position of the throttle valve of a carburetor, and there are various structures available. Are known. In this,
One that is attracting attention is the one that combines a throttle switch with a throttle adjustment screw that adjusts the idle opening of the throttle valve. This is described in Japanese Utility Model Application Publication No. 113029/1984, and it is described that the throttle switch mechanism is maintained at the initial setting state and the throttle valve is idle r.
It is said that it is possible to perform a 5σ degree adjustment. It is certainly recognized that this method is more effective than the conventional method in terms of appropriately adjusting the relationship between the switching timing and the throttle valve opening.

[Problems to be Solved by the Invention] However, from the viewpoint of the function of the throttle switch, it is difficult to satisfy recent demands for responsiveness, stability, etc. with the above configuration.

In embodiments in which the switch mechanism is configured to operate at a predetermined angle before the idle time, in addition to the relative displacement between the screw boss and the spindle, the amount of sliding on the spindle is also required to ensure the predetermined switching action. There is a variable factor such as the distance between the contact (movable contact) and the (fixed) contact, and it must be said that it is difficult to stabilize these due to the structure. Although this example is mentioned, it is still an opposing contact type switching mechanism in which the movable contact and the fixed contact face each other, and the distance between both contacts is large, so problems remain in terms of responsiveness, etc. .

In particular, in the above configuration, rim-like vibration is unavoidable, and bouncing and chattering are likely to occur, so there is a concern that the contacts may be worn out or welded. In the field of electronics, a switch using a conductive rubber contact as a movable contact is known as a switch of the opposed contact type in which such chattering hardly occurs. However, in order to apply this opposed contact switch equipped with conductive rubber contacts to the above-mentioned throttle switch, there are many problems that must be resolved. However, even if this method were adopted, it would not solve problems such as responsiveness caused by the distance between the contacts.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a throttle switch that has excellent responsiveness and performs a stable switching action without causing chattering.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a cylindrical body that accommodates and rotatably supports a throttle valve, and a throttle lever that is connected to the throttle valve and rotates integrally with the throttle valve. The throttle switch to be attached to the other has a bottomed cylindrical case and a cylindrical extension extending from the bottom of the case, and the extension is connected to either the throttle lever or the cylindrical body. a housing that is attached to the housing; and a shaft that is inserted into the extending portion of the housing in the axial direction, and one end of which normally projects a predetermined distance from the end surface of the extending portion and faces the other of the throttle lever and the cylindrical body. a slider abutting the other end of the shaft and slidably fitting into the case; and a slider attached to either an end face of the slider or a wall face inside the case opposite to the end face. a fixed contact; a pressure-sensitive conductor that abuts the fixed contact and is attached to the other of the end face of the slider and a wall inside the case; and urging means for urging the slider in the direction of the shaft. It is equipped with the following.

Regarding the above-mentioned throttle switch, the pressure-sensitive four electric body is made of an annular pressure-sensitive conductive rubber having an annular protrusion on the surface facing the fixed contact, and the slider is made of a small diameter with an annular groove formed on the outer periphery. The pressure-sensitive conductive rubber is fitted into an annular groove of the stepped piston, and a guide cylinder is fitted into the case of the housing, and the pressure-sensitive conductive rubber is fitted into the annular groove of the stepped piston. The stepped piston may be slidably housed.

Further, a sealing member is interposed between the hollow part of the cylindrical extension part and the shaft, and the shaft is slidably supported in the hollow part of the extension part in a liquid-tight manner. You can also do that.

[Operation] The throttle switch configured as described above is arranged such that, for example, one end of the shaft faces the throttle lever, and the extending portion of the housing is attached to the cylindrical main body.

When the throttle valve is in the fully closed position, one end of the shaft is pressed by the throttle lever, and the pressing force is transmitted to the slider that comes into contact with the other end of the shaft. Due to this pressing force, the X mover is pressed in a direction away from the fixed contact against the urging force of the urging means. At this time, for example, the pressing force applied to the pressure-sensitive conductor attached to the wall of the fH element with respect to the fixed contact attached to the wall inside the case is the minimum, and therefore the resistance value of the pressure-sensitive conductor is maximum. It is.

When the throttle valve rotates in the opening direction from the fully closed position, the throttle lever moves in a direction away from one end of the shaft. As a result, the pressing force applied to the slider via the shaft is reduced, and instead the pressing force in the direction of the fixed contact by the biasing means is increased. Therefore, the pressing force applied to the pressure-sensitive conductor increases and the resistance value decreases. And when the throttle lever separates from the shaft, the pressure is 1? The resistance value of body a is the minimum.

In this manner, the resistance value of the pressure-sensitive conductor changes in response to rotation of the throttle lever, and this change in resistance value is detected via the fixed contact that comes into contact with the pressure-sensitive conductor. Therefore, if you set it as non-conducting when the resistance value increases and exceeds a predetermined value, and as conductive when the resistance value decreases and becomes below a predetermined value,
When the throttle valve is opened from the fully closed position, a switching operation is performed from non-conductive to conductive, and when the throttle valve is operated in the opposite direction, from conductive to non-conductive.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show an embodiment of the throttle switch of the present invention, and the housing according to the present invention includes an outer case 2a that is a metal cylinder with a bottom and a cylindrical extension integrally extending from the bottom of the outer case 2a. An inner case 2c, which is a cylindrical body made of resin and has a bottom, is fitted from the open end of the outer case 2a to define a switch chamber between the outer case 2a and the inner case 2c.

A male thread is formed on the outer periphery of the extending part 2b, and the end of the hollow part of the extending part 2b, that is, the bottom of the outer case 2a, has a large diameter, so that a stepped hole 2d is formed. The shaft 3 is inserted into this stepped hole 2d, and the tip end 3 of the shaft 3 is inserted into the stepped hole 2d.
a protrudes from the end surface of the extending portion 2b.

The base portion 3b of the shaft 3 is formed into a cylindrical shape having a larger diameter than the main body portion of the shaft 3. An annular groove is formed on the outer periphery of the base portion 3b, into which an O-ring 4 is fitted, and the base portion 3b is slidably fitted in a liquid-tight manner within the large diameter portion of the stepped hole 2d. Therefore, the inside of the outer case 2a is liquid-tightly sealed from the space communicating with the outside via the extension 2b. Note that other sealing members may be used in place of the O-ring 4, and the cross-sectional shape thereof is not limited to a circular shape but may be of any shape.

Inside the switch chamber defined by the outer case 2a and the inner case 2C, a disc-shaped insulating substrate 6 to which the fixed contact 5 is fixed is disposed at the bottom of the outer case 2a. On the other hand, a resin cylindrical guide cylinder 7 is fitted inside the inner case 2C, and its end face and outer case 2a are fitted.
A fixed contact 5 and an insulating substrate 6 are sandwiched between the bottom part and the bottom part.

A hole 6a having approximately the same diameter as the large diameter portion of the stepped hole 2d described above is bored in the center of the insulating substrate 6, and the fixed contact 5 is inserted into this hole 6.
It is arranged around a.

That is, as is clear from FIG. 2, the fixed contact 5 consists of a pair of substantially U-shaped contacts 5a and 5b fixed on an insulating substrate 6, each having a lead wire 1! a,! 1b is connected. These lead wires 11a.

11b is led out to the outside via a groove formed on the outer surface of the guide cylinder 7 and/or the inner surface of the inner case 2C. The lead-out portions of the lead wires 11a and IXb are fixed to the outer surface of the inner case 2c with molded resin 12.

A slider 8 is slidably fitted into the guide cylinder 7. This slider 8 is made of resin and is formed in the shape of a stepped piston, with its small diameter portion sliding within the hole 6a of the base plate 6, and its large diameter portion sliding within the guide cylinder 7. It is located. Further, an annular groove 8 is provided on the outer periphery of the small diameter portion of the slider 8.
8 is formed, and a protrusion 8b is formed at the tip at the center of the end surface.

An annular pressure-sensitive conductor 9 is fitted into the annular groove 88 , and an annular projection 9 a formed on the end surface thereof is in contact with the fixed contact 5 . The protrusion 8b of the slider 8 fits into a groove formed in the center of the end surface of the base 3b of the shaft 3, and the two are joined.

A compression spring 10 is interposed between the end surface of the large diameter portion of the slider 8 and the bottom surface of the inner case 2C. Therefore, under normal conditions, the slider 8 is urged in the direction of the shaft 3, and the annular protrusion 9a of the pressure-sensitive conductor 9 is pressed against the fixed contact 5 with a constant load, and the tip of the shaft 3 connected to the slider 8 The portion 3a projects a predetermined distance l11 (Il) from the end surface of the extending portion 2b.

Note that the axial length of the annular protrusion 9a in its free state is equal to or greater than the above-mentioned predetermined distance (1).
Even if the annular projection 9a is pressed until it is aligned with the end surface of the extension portion 2b, the annular projection 9a
is not separated from the fixed contact 5. However, a configuration may be adopted in which the two can be separated from each other, and the biasing force of the compression spring 10 is set to be smaller than the biasing force against the throttle valve, which will be described later.

The pressure-sensitive conductor 9 is made of an elastic material such as rubber or thermoplastic resin mixed with particles of conductive metal or carbon, and has a predetermined pressure resistance characteristic that changes its resistance value when pressure is applied. are doing.

Specifically, carbon black and metal particles are mixed with insulating rubber to maintain an insulating state at all times, and when an external load is applied, the compressive strain causes gaps between the metal particles depending on the magnitude of the load. Pressure-sensitive conductive rubber is used that shortens the distance and provides continuous conductivity. Regarding this specific configuration,
For example, it is described in Japanese Patent Application Laid-Open No. 59-11343, so the explanation will be omitted.

When the throttle switch 1 is in the state shown in FIG. 1 and the annular protrusion 9a of the pressure-sensitive conductor 9 is pressed against the fixed contact 5, the pressure-sensitive conductor 9 has a resistance value according to its pressure resistance characteristics. is the minimum.

The tip 3a of the shaft 3 is pressed in the direction of the slider 8, and the slider 8 moves against the compression spring 10 into the guide cylinder 7.
The fixed contact 5 of the annular protrusion 9a of the pressure-sensitive conductor 9
When the pressing force against the pressure-sensitive conductor 9 decreases, the resistance value of the five pressure-sensitive conductors 9 increases. Then, the tip end 3a of the shaft 3 is connected to the extending portion 2.
The resistance value becomes maximum when it is pressed until it lines up with the end face of b.

Therefore, between the lead wires fla and 11b, that is, the contacts 5a and 5
The switching state between b is set such that when the resistance value of the pressure-sensitive conductor 9 increases and exceeds a predetermined value, it is non-conducting, and when the resistance value decreases and becomes below a predetermined value, it is called conductive.

Thus, switching between the lead wires 11a and llb can be performed in accordance with the pressing force applied between the annular protrusion 9a and the fixed contact 5 while the annular protrusion 9a is in contact with the fixed contact 5. That is, switching is possible with a minute displacement of the pressure-sensitive conductor 9, and the stroke of the shaft 3 necessary for the switching action is small, for example, can be suppressed to 1 mm or less. Moreover, since the pressure-sensitive conductor 9 is supported by the slider 8, and the slider 8 is guided by sliding inside the guide cylinder 7, the pressure distribution on the annular protrusion 9a is uniform, and the hysteresis in the switching action is also kept small. and stable switching is performed. Note that the lead wire 11a.

It is also possible to set different threshold levels for conduction and non-conduction of xxblJ.

Figure 3 shows the throttle switch 1 having the above configuration installed in the carburetor, with the throttle valve 22
is housed in the cylindrical body 20 and rotatably supported by a glaze 21, and is connected to a throttle lever 23 outside the cylindrical body 20 via a shaft 21. That is, the throttle lever 23 rotates integrally with the throttle valve 22, and the throttle valve 22 is rotated by a spring (not shown).
3, and is biased counterclockwise in FIG.

On the other hand, a bracket 24 is erected on the outside of the cylindrical body 2o at a position facing the throttle lever 23, and the extending portion 2b of the throttle switch 1 is screwed together with a nut 25 into a female threaded hole formed in the bracket 24. has been done. As a result, the tip 3a of the shaft 3 of the throttle switch 1 is disposed opposite to the tip of the throttle lever 23, and by rotating the throttle switch 1 screwed to the bracket 24, the throttle lever 2 is moved in the axial direction.
Approach and separate from the tip of 3.

Here, since the compression spring 10 of the throttle switch 1 is smaller than the counterclockwise biasing force of the throttle valve 22, the throttle lever 23 rotates according to the biasing force. When the throttle switch 1 is pressed, the tip 3a of the shaft 3 is buried in the extension 2b, and the end surface of the extension 112b is locked in contact with the tip of the throttle lever 23. Ru. Therefore, by rotating the throttle switch 1, the extending portion 2b pushes the throttle lever 23 to adjust the idle opening degree of the throttle valve 22, and the nut 25 fixes the throttle valve 22 at the adjusted position.

When the throttle valve 22 is in the fully closed position, the shaft 3 of the throttle switch 1 is pressed by the tip of the throttle lever 23, so the pressure-sensitive conductor 9
The pressing force applied to the pressure sensitive conductor 9 is therefore minimal.
The resistance value of fib is the maximum, and there is no conduction between the lead wire 11a and fib.

When the shaft 21 is rotated clockwise and the throttle valve 22 is rotated in the opening direction, the throttle lever 23 is moved toward the shaft 3.
moves in a direction away from the tip 3a. Therefore, the pressure-sensitive conductor 9 is pressed against the fixed contact 5 by the compression spring 10, and the resistance value of the pressure-sensitive conductor 9 decreases, and when it reaches a predetermined value, conduction is established between the lead wires 1.1a and fib. That is, the throttle switch 1 constitutes a switch that switches from non-conducting to conducting when the throttle valve 22 is opened from the fully closed position.

The conduction and non-conduction between the lead wires 11a and fib, that is, the conduction and non-conduction between the contacts 5a and 5b, are determined by the lead wires 1.1 and 1.1.
The judgment is made by a control circuit (not shown) to which a and fib are connected, and depending on the conduction or non-conduction, an acceleration fuel increase device (not shown) or a deceleration fuel cut device (not shown) is connected to this control circuit. etc., and appropriate air-fuel ratio control for the internal combustion engine is performed.

It is also possible to reverse the switching operation of the throttle switch 1 so that it switches from conduction to non-conduction when it changes from the fully closed position to the open operation. In this case, the pressure sensitive The conductor 9 may be interposed between the bottom surface of the slider 8 on the side opposite to the protrusion 8b and the bottom surface of the inner case 2c.

As a result, when the throttle valve 22 is in the fully closed position and the shaft 3 is pressed, the pressure-sensitive conductor 9 is pressed against the slider 8 and the resistance value is minimized, that is, it is in a conductive state, and the shaft 3 is pressed. As soon as the pressing force is removed, the resistance value of the pressure-sensitive conductor 9 becomes maximum and it immediately becomes non-conductive.

Fig. 4 shows another embodiment in which the throttle switch 1 is attached to the carburetor. In the embodiment shown in Fig. 3, the throttle switch 1 has a structure in which it directly functions as a throttle adjustment screw. In contrast, in this embodiment, an adjustment screw 26 is provided on the throttle lever 23, and the idle opening degree of the throttle valve 22 is adjusted by bringing the shaft 3 of the throttle switch 1 into contact with the tip of the throttle lever 23. That is. Therefore, the throttle switch 1 is fixed to the bracket 24 via the washer 27, and functions as a stopper for the throttle lever 23.

In such a configuration, it is necessary to add an adjustment screw 26 and a spring to bias it compared to the embodiment shown in FIG. Therefore, compared to the conventional throttle switch and throttle adjustment screw that are provided separately, the adjustment target is only the idle opening, making the operation easier. Furthermore, the throttle switch 1 can ensure stable switching operation without chattering as described above.

In the embodiments shown in FIGS. 3 and 4, the throttle switch l is mounted on the bracket 24, that is, on the cylindrical body 20 side, but it may also be mounted on the throttle lever 23 side. However, in that case, is throttle valve 2
Since the throttle switch 1 rotates around the shaft 2 as the throttle switch 2 rotates, consideration must be given to the routing of the lead wires 11a and jlb, as in the technique described in the above-mentioned publication.

[Effects of the Invention] Since the present invention is configured as described above, it produces the effects described below.

That is, in the throttle switch of the present invention, opening and closing of the throttle valve can be detected by minute displacements of the shaft, so when the throttle valve slightly opens from the fully closed position, it changes from non-conducting to conducting, or from conducting to non-conducting. By setting the switch to switch, the response becomes extremely good compared to the conventional technology, and since there is no variation in the switching timing, the detection accuracy is improved. Moreover, it also has a function to adjust the idle opening degree of the throttle valve, and can adjust the idle opening degree without affecting the function as a throttle switch.

In particular, in the throttle switch of the present invention, since the switching operation is performed in accordance with the resistance change occurring in the pressure-sensitive conductor, chattering does not occur, and therefore, it is possible to eliminate the chattering countermeasures required for conventional throttle switches. No electrical circuit is required.

Furthermore, since the stroke of the shaft is small, a sealing member can be disposed between the shaft and the cylindrical body, thereby ensuring a liquid-tight seal and improving the durability of the throttle switch.

[Brief explanation of the drawing]

1 is a longitudinal cross-sectional view of a throttle switch according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line 11-11 in FIG. 1, and FIG. 3 is a state in which the throttle switch shown in FIG. 1 is attached to a carburetor. FIG. 4 is a front view showing another embodiment in which the throttle switch shown in FIG. 1 is attached to a carburetor. l...Throttle switch. 2...Housing. 2a...Outer case, 2b...Extending portion 2c
...Inner case. 3...shaft, 4...0 ring. 5...Fixed contact, 6...Insulating board. 8...Slider. 9... Pressure-sensitive conductor, 9a... Annular projection. 10... Compression spring (biasing means). 20...Cylindrical body. 22... Throttle valve. 23...Throttle lever diagram

Claims (1)

[Claims] (1) A throttle switch that is mounted on the other of a cylindrical body that accommodates and rotatably supports a throttle valve, and a throttle lever that is connected to the throttle valve and rotates integrally with the throttle valve, A housing having a bottomed cylindrical case and a cylindrical extension extending from the bottom of the case, the extension being attached to either the throttle lever or the cylindrical body; a shaft through which the extending portion of the shaft is inserted in the axial direction, and one end of which normally protrudes a predetermined distance from the end surface of the extending portion and faces the other of the throttle lever and the cylindrical body, and the other end of the shaft; A slider that abuts and slidably fits into the case, a fixed contact attached to either an end face of the slider or a wall face inside the case opposite to the end face, and a fixed contact attached to the fixed contact. It is characterized by comprising: a pressure-sensitive conductor that comes into contact with and is attached to the other of the end face of the slider and the wall inside the case, and a biasing means that biases the slider in the direction of the shaft. throttle switch.