JP2000046632A - Liquid level detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid level detecting device having excellent contact reliability between a moving contact slider and a conductor pattern on an insulating board. SOLUTION: This device is composed by having a float for operating by following a liquid level in a fuel tank, a moving contact slider 11 installed on a contact board 8 for moving sequentially with the movement of the float, and an insulating board 6 having a conductor pattern 4 thereon on which the moving contact slider 11 is slid. In this case, one moving contact slider 11 is formed on the contact board 8 and two points of contact 12 for contacting with the conductor pattern 4 are formed by projecting the moving contact slider 11 to have two roughly-hemispheric shapes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid level detecting device for measuring a liquid level in a fuel tank of a vehicle or the like, and more particularly to a liquid level detecting device characterized by a sliding contact sliding on a conductor pattern on an insulating substrate. Related to the device.

[0002]

2. Description of the Related Art Conventionally, a liquid level detecting device 1 is housed in a fuel tank 2 and is provided on a mounting plate 3 attached to an opening of the fuel tank 2. Under the mounting plate 3, an insulating substrate 6 made of ceramic on which a conductor pattern 4 and a resistor 5 are formed by printing is mounted. Further, the liquid level detecting device 1 is provided with a contact plate 8 having a sliding contact 7 that slides on the conductor pattern 4. This contact plate 8
From the float 9 that moves up and down according to the fuel level,
In addition, it is supported and fixed on the insulating substrate 6 so as to be movable in accordance with the liquid level through the insulating substrate 6. Therefore, the vertical movement of the liquid surface is transmitted to the contact plate 8 via the float 9 and the arm 10, and the sliding contact 7 slides on the conductor pattern 4, thereby sliding with the conductor pattern 4 on the insulating substrate 6. The resistance value changes depending on the position of the conductor pattern 4 in contact with the contact 7, whereby the amount of liquid in the fuel tank 2 is detected and displayed on a display (not shown).

[0003]

However, the shape of the sliding contact 7 is hemispherical and the surface is finished like a mirror surface, and the contact point with the conductor pattern 4 is one point. For this reason, when dusts such as foreign matter adhere to the contact point or its vicinity, there is a possibility that a contact failure may occur.

Accordingly, the present invention is directed to a liquid level detecting device which pays attention to the above problem, and has excellent contact reliability between a sliding contact and a conductor pattern of an insulating substrate.

[0005]

In order to achieve the above object, the present invention provides a float operating following a liquid level in a fuel tank, and a sliding contact provided on a contact plate interlocked with the movement of the float. And a liquid level detection device having an insulating substrate provided with a conductor pattern on which the sliding contact slides, wherein the contact plate is provided with one sliding contact, and the sliding contact is brought into contact with the conductor pattern. A plurality of contact points are formed.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A liquid level detecting device 1 according to the present invention comprises a float 9 operating following a liquid level in a fuel tank 2 and a slide plate provided on a contact plate 8 interlocked with the movement of the float 9. In a liquid level detection device having a contact 11 and an insulating substrate 6 provided with a conductor pattern 4 on which the sliding contact 11 slides, one contact 11 is provided on the contact plate 8 and two sliding contacts 11 are provided. Conductor patterns 4 projecting into two substantially hemispherical shapes
Is formed with two contact points 12 that come into contact.

Further, as a second embodiment, a plurality of fine irregularities are formed by making cuts in the sliding contact 11, and the plurality of fine projections serve as contact points 13 where they contact the conductor pattern 4.

Further, as a third embodiment, a cross-shaped notch is formed in the sliding contact 11 so that the sliding contact 11 projects in a semicircular shape in four cross-sections, and contacts the four projecting portions respectively. Point 14 is provided.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to FIGS. 1 to 3.

As shown in the drawing, the liquid level detecting device 1 of the present invention
Is formed, for example, by printing a plurality of rows of conductor patterns 4 in a fan shape, for example, by printing, on an insulating substrate 6 made of ceramic, and printing a part of the conductor patterns 4 by a resistor 5 over a plurality of rows, for example. It is adhered by. One sliding contact 11 that slides on the conductor pattern 4 is fixed to the contact plate 8 interlocked with the float 9 by means such as caulking.

The sliding contact 11 is made of a silver-palladium alloy. The sliding contact 11 protrudes in two substantially hemispherical shapes, and is provided with two contact points 12 that come into contact with the conductor pattern 4. The two contact points 12 contact the same conductor pattern 4 in a direction perpendicular to the sliding direction of the contact plate 8 indicated by the arrow in the figure. The two contact points 12 are formed when the sliding contact 11 is fixed to the contact plate 8, and the sliding contact 11 is securely fixed by the contact plate 8 so as not to rotate.

As a modified example of the first embodiment, the direction in which the contact points 12 are arranged may be provided in parallel with the sliding direction of the contact plate 8. In this case, it is also possible to set the two contact points 12 so as to make contact with different conductor patterns 4 depending on the distance between the contact points 12 and the width of the conductor pattern 4 itself and the distance between the conductor patterns 4. In addition, it is also possible to set so that only one of the two contact points 12 contacts the conductor pattern 4.

Further, as another modified example of the first embodiment,
The direction in which the contact points 12 are lined up with respect to the sliding direction of the contact plate 8
It may be provided at an angle such as 45 °.

Next, a second embodiment of the present invention will be described with reference to FIGS. 4 and 5. The same parts and corresponding parts as those in the above-mentioned conventional example and the above-mentioned embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. .

The contact portion of the sliding contact 11 which contacts the conductor pattern 4 is formed so as to have a mesh-shaped cut, and the cut contact portion is provided with fine irregularities. I have. The projecting portion of the fine irregularities is the contact point 13, and the projecting portion of the fine contact point contacts the conductor pattern 4, and the sliding contact 11 and the conductor pattern 4 are reliably electrically connected.

Next, a third embodiment of the present invention will be described with reference to FIGS. 6 and 7. The same parts and corresponding parts as those of the above-mentioned conventional example and the above-mentioned embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. .

A contact portion of the sliding contact 11 that contacts the conductor pattern 4 is cut into a cross shape, and the sliding contact 11 is formed by projecting four cross-sectional shapes into a semicircular shape. Each of the four sliding contact points 11 has a contact point 14. According to the present embodiment, since there are four contact points 14, the sliding contact 11 and the conductor pattern 4
Contact reliability with the conventional device is improved.

In each of the above-mentioned embodiments, the contact points 12, 1 which are provided on one sliding contact 11 and come into contact with the conductor pattern 4 are provided.
By forming a plurality of 3 and 14, the contact reliability between the sliding contact 11 and the conductor pattern 4 is improved. In addition, since the plurality of contact points 12, 13, and 14 are formed by one sliding contact 11, it is not necessary to form a plurality of sliding contacts 11 on the contact plate 8, so that one sliding contact as in the related art is used. 11 only needs to be crimped to the contact plate 8, the man-hour for fixing the sliding contact 11 does not change, and the contact points 12, 13, 14 can be formed by the same header processing as in the past. The liquid level detecting device of the present invention can be obtained without increasing the manufacturing cost.

[0019]

As described above, according to the present invention, it is possible to obtain a liquid level detecting device which achieves the intended purpose, has excellent contact reliability, and does not involve an increase in manufacturing cost.

[Brief description of the drawings]

FIG. 1 is a top view of a main part of a liquid level detecting device according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a bottom view of the contact plate of the embodiment.

FIG. 4 is a bottom view of a contact plate according to a second embodiment of the present invention.

FIG. 5 is a sectional view taken along line BB in FIG. 4;

FIG. 6 is a bottom view of a contact plate according to a third embodiment of the present invention.

FIG. 7 is a sectional view taken along line CC in FIG. 6;

FIG. 8 is a diagram in which a conventional liquid level detecting device is attached to a fuel tank.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid-level detection device 2 Fuel tank 3 Mounting plate 4 Conductor pattern 5 Resistor 6 Insulating board 7,11 Sliding contact 8 Contact plate 9 Float 10 Arm 12,13,14 Contact point

Claims (1)

[Claims] 1. A float which operates following a liquid level in a fuel tank, a sliding contact provided on a contact plate interlocked with the movement of the float, and a conductor pattern on which the sliding contact slides. In a liquid level detection device having an insulating substrate,
A liquid level detecting device, wherein one contact point is provided on the contact plate, and a plurality of contact points for contacting the conductor pattern are formed on the contact point.