JPH059468Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an idle position detection switch for an internal combustion engine.

[Prior Art] In an internal combustion engine, an idle position detection switch is used when controlling the amount of fuel supplied in accordance with the opening degree of a throttle valve.

A conventional example of this is shown in FIG.

That is, in the figure, a substantially cylindrical housing 2 attached to the throttle body 1 includes a push rod 3, a movable contact 4 provided at the lower end of the push rod 3, and a movable contact 4 disposed at a position opposite to the movable contact 4. A fixed contact 5 is provided inside. Note that the throttle body 1 is attached to an engine (not shown) and grounded. The push rod 3 is slidably fitted and supported inside a small diameter portion 6a of a substantially cylindrical guide 6 provided within the housing 2, and its upper end portion protrudes from the opening at the tip of the housing 2. A ring-shaped plate 7 is fitted onto the outer periphery of the lower end of the push rod 3 located inside the large diameter portion 6b of the guide 6. A substantially cylindrical insulator 8 is disposed inside the lower end opening of the housing 2, and the insulator 8 is fitted onto the inner periphery of the housing 2 with its large diameter portion 8a. The small diameter portion 8b of the insulator 8 is fitted onto the outer periphery of the lower end of the push rod 3. A lead plate 9 is interposed between the lower end surface of the large diameter portion 6b of the guide 6 and the end surface of the large diameter portion 8a of the insulator 8. A spring 10 as an elastic member is interposed between the plate 7 and the lead plate 9. Therefore, the push rod 3 is normally urged by the spring 10 in a direction opposite to the swinging end 12a of the stopper 12 connected to the valve shaft 11 of the throttle valve, and is pressed into contact with the stopper 12. This allows it to slide against the elastic force.

A terminal 13 is coupled to the fixed contact 5, and the terminal 13 is guided to the outside via a resin connector 14 fitted to the inner periphery of the lower end opening of the housing 2. This connector 14 is connected to the housing 2
It is held fixed to the housing 2 by caulking a portion 15 extending further from the lower end opening. On the other hand, a threaded portion 2a is provided on the outer periphery of the upper end of the housing 2.
is formed, and is screwed onto a female thread 1a provided on the throttle body 1 with this threaded portion 2a. Note that 16 is a seal rubber attached to the outer periphery of the upper end of the housing 2.

Next, the operation of this configuration will be explained.

When the valve shaft 11 of the throttle valve is rotated in response to the fully closing of the throttle valve, the push rod 3 is pressed by the swinging end 12a of the stopper 12 against the elastic force of the spring 10. A movable contact 4 provided at the lower end of the push rod 3 contacts a fixed contact 5. At this stage, the stopper 12 is positioned. The current from the terminal 13 is then grounded to the fixed contact 5, push rod 3, plate 7, spring 10, lead plate 9, housing 2 and throttle body 1.
The idle position will be detected.

[Problems to be Solved by the Invention] However, in such a conventional idle position detection switch, both ends of the spring 10 for electrically connecting the plate 7 to the lead plate 9 cannot be connected to the plates 7 and 9 by the spring force alone. are in contact. In this way, the mere pressure of the spring 10 causes contact resistance, and this tendency becomes even stronger if a sufficient detection signal cannot be output, or if these contact surfaces become contaminated with oil or become oxidized. Furthermore, if the spring 10 rotates and the contact surfaces differ between the plates 7 and 9, there is instability in that the magnitude of the detection signal differs for the above-mentioned reason.

This invention was devised to solve these conventional problems, and the object is to provide an idle position detection switch that can reliably and stably output an output when detecting an idle position.

[Means for Solving the Problems] Therefore, in the present invention, both ends of the spring 10 are fixed to respective members.

[Function] In this invention, both ends of the spring are fixed, so the contact resistance at these parts is reduced.
A more stable signal can be obtained.

[Example] An example of the present invention will be described below with reference to FIG. In this figure, the same elements as those of the conventional device are given the same reference numerals to simplify the explanation.
17 is a fixed ring provided at the lower end of the push rod 3; 18 is a support disk supporting the fixed contact 5;
19 is a terminal piece that makes electrical contact with the fixed contact 5 supported by the support disk 18, and 20 is the end of a lead wire crimped onto this terminal piece 19. 22 is a stepped portion formed at the lower open end of the housing 2.

The upper end of the spring 10 has a small turn 10a extending radially inward and matching the small diameter portion of the lower end of the push rod 3. This winding portion 10a is sandwiched and held between the lower end of the push rod 3 and the plate 7 by fixing a fixing ring 17 to the lower end of the push rod 3. Thus, the upper end of the spring 10 is tightly electrically connected to the movable contact 4 side. The lower end of the spring 10 extends radially outward to form a large winding portion 10b. This large winding part 10b
is located in a guide groove 8e provided on the outer periphery of the insulator 8, and is fastened to the stepped portion 22 of the housing 2. Thus, the lower end of the spring is tightly electrically connected to the housing 2 side. Note that this clamping is achieved at the same time that the connector 14 is fixedly held to the housing 2 by caulking the caulking portion 15.

A radially outwardly extending portion of the lower end of the spring 10 exits through a recess 8d formed in the insulator 8 and is connected to the large winding portion 10b.
As described above, the insulator 8 has a guide groove 8e on its outer periphery. Furthermore, insulator 8
has a support 8c at a position diametrically opposed to the recess 8d. The large-diameter portion 6b of the guide 6 faces the insulator 8 and substantially surrounds the spring 10, the movable contact 4, etc., and has a large-diameter cutout groove 6c for receiving the support column 8c of the insulator 8. The portion 6b has. A protrusion 7a extending radially from the plate 7 is further engaged with the cutout groove 6c so as to be movable in the axial direction.

Note that a wave washer 21 is provided between the housing 2 and the large diameter portion 6b of the guide 6. A rubber cover 23 surrounds the connector 14.

According to this configuration, the plate 7 electrically connected to the movable contact 4 is reliably maintained in a state where it is electrically connected (grounded) to the housing 2 via the spring 10.

Although this embodiment shows a structure in which both ends of the spring 10 are clamped, it is obvious that the effect of the present invention can be obtained by welding, caulking, crimping, etc. without being limited to this. .

[Effects of the Invention] As explained above, according to the present invention, the movement of the push rod when detecting the idle position can be reliably detected and the reliability of the function of the idle position detector can be improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of an idle position detection switch according to the present invention, and FIG. 2 is a sectional view of a conventional idle position detection switch. In the figure, 1 is a part of the throttle body, 2
3 is a housing, 3 is a push rod, 4 is a movable contact, 5 is a fixed contact, 10 is a spring, 10a is one end of the spring, and 10b is the other end of the spring. Note that the same reference numerals in each figure indicate the same members or corresponding parts.

Claims (1)

[Claims for Utility Model Registration] A metal housing fixed and supported by a throttle body and electrically connected to the body, which is attached to the housing so as to be slidable in the axial direction, and has one end protruding from the housing to operate the throttle valve. a push rod configured to be in contact with a stopper provided on the valve stem of the valve; a movable contact provided at the inner end of the push rod; a fixed contact insulatively fixed to the housing at a position opposite to the movable contact; a metal spring biasing the push rod back to its initial position, the spring also having the function of grounding the movable contact to the housing;
Accordingly, in an idle position detection switch in which the stopper of the throttle valve comes into contact with the push rod, both contacts come into contact and generate an idle position signal, one end of the metal spring is fixed to the movable contact side, and the other end is fixed to the movable contact side. An idle position detection switch, characterized in that the switch is fixed to the housing side.