JP2007139679A - Liquid level detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid level detector provided with a sliding contact hardly affected by sulfur. <P>SOLUTION: This liquid level detector 1 has a float operated to follow a liquid level, the sliding contact 11 interlocked with the float, and an insulation substrate 6 with a conductor pattern 4 slid with the sliding contact 11, and the sliding contact 11 comprises an alloy of palladium and ruthenium, and is constituted to bring a weight ratio of the palladium to the ruthenium into 90wt.% or more of palladium and 10wt.% or less of ruthenium. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

    The present invention relates to a liquid level detection device for measuring the amount of liquid in a fuel tank of a vehicle or the like, and more particularly to a liquid level detection device characterized by a sliding contact sliding on a conductor pattern of an insulating substrate.

Conventionally, the liquid level detection 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. An insulating substrate 6 made of ceramic on which the conductor pattern 4 and the resistor 5 are printed is attached below the attachment plate 3. Further, the liquid level detection device 1 is provided with a contact plate 8 having a sliding contact 7 that slides on the conductor pattern 4. The contact plate 8 is supported and fixed so as to move on the insulating substrate 6 via an arm 10 from a float 9 that moves up and down according to the fuel level. Accordingly, the vertical movement of the liquid level is transmitted to the contact plate 8 through the float 9 and the arm 10, and the sliding contact 7 slides on the conductive pattern 4 to slide with the conductive pattern 4 on the insulating substrate 6. The contact point 7 comes into contact, and the resistance value changes depending on the position of the contacted conductor pattern 4, thereby detecting the amount of liquid in the fuel tank 2 and displaying it on a display (not shown).
JP 2003-194618 A JP 2003-287455 A

  However, the material used as the sliding contact 7 includes a copper nickel zinc (Cu, Ni, Zn) alloy (a white or a silver), a silver nickel alloy, etc., but is sulfided due to the influence of sulfur contained in the fuel. There were problems such as.

  Therefore, the present invention pays attention to the above-mentioned problems and provides a liquid level detection device provided with a sliding contact which is not easily affected by sulfur.

  In order to solve the above problems, the present invention provides a float that operates following the liquid surface, a sliding contact that is linked to the movement of the float, and an insulating substrate that is provided with a conductor pattern on which the sliding contact slides. In the liquid level detecting device, the sliding contact is made of only palladium.

  Further, in the liquid level detection device having a float that operates following the liquid level, a sliding contact that is linked to the movement of the float, and an insulating substrate that is provided with a conductor pattern on which the sliding contact slides, The moving contact is made of an alloy of palladium and ruthenium.

  The weight ratio of palladium to ruthenium is such that palladium is 90% by weight or more and ruthenium is 10% by weight or less.

  The weight ratio of palladium to ruthenium is 90% by weight of palladium and 10% by weight of ruthenium.

  The present invention can provide a liquid level detection device having a sliding contact that is not easily affected by sulfur.

  The present invention relates to a liquid surface having a float that operates following the liquid surface, a sliding contact 11 that is linked to the movement of the float, and an insulating substrate 6 that is provided with a conductor pattern 4 on which the sliding contact 11 slides. In the detection device 1, the sliding contact 11 is made of only palladium. By comprising in this way, the liquid level detection apparatus provided with the sliding contact 11 which is hard to be influenced by sulfur can be provided.

  Further, a liquid level detecting device having a float that operates following the liquid level, a sliding contact 11 that is linked to the movement of the float, and an insulating substrate 6 that is provided with a conductor pattern 4 on which the sliding contact 11 slides. 1, the sliding contact 11 is made of an alloy of palladium and ruthenium. By comprising in this way, the liquid level detection apparatus provided with the sliding contact 11 which is hard to be influenced by sulfur can be provided.

  The weight ratio of palladium to ruthenium is such that palladium is 90% by weight or more and ruthenium is 10% by weight or less. By comprising in this way, the liquid level detection apparatus provided with the sliding contact which is hard to be influenced by sulfur can be provided at low cost.

  The weight ratio of palladium to ruthenium is 90% by weight of palladium and 10% by weight of ruthenium. By comprising in this way, the liquid level detection apparatus provided with the sliding contact which is hard to be influenced by sulfur can be provided at low cost.

  Hereinafter, the present invention will be described with reference to FIGS. 1 and 2, and the same parts as those in the conventional example are denoted by the same reference numerals and detailed description thereof will be omitted.

  FIG. 1 is a front view of an essential part of the liquid level detection device of the present invention, and FIG.

  As shown in FIGS. 1 and 2, the liquid level detection device 1 of the present invention includes a plurality of rows of conductor patterns 4 in a fan shape, for example, printing, drying, and firing, at appropriate intervals on an insulating substrate 6 made of ceramic. For example, the resistor 5 is formed in a plurality of rows over a plurality of rows of the conductor pattern 4 through, for example, the printing, drying, and firing processes in the same manner as the conductor pattern. A 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 fixing of the sliding contact 11 to the contact plate 8 is not limited to caulking, and may be fixed using means such as welding. Also, a structure in which a protective layer made of ruthenium oxide or the like is formed on the conductor pattern 4 to prevent the conductor pattern from being sulfided may be employed.

  The material of the sliding contact 11 is an alloy of palladium and ruthenium. In this example, the weight ratio of palladium to ruthenium is 90% by weight of palladium (Pd) and 10% by weight of ruthenium (Ru), and the tolerance is around 1% by weight. Actually, a small amount of impurities are mixed in addition to palladium and ruthenium, but this does not impede the effects of the present embodiment. Since palladium and ruthenium are both precious metals and are elements that are not easily affected by sulfur, the sliding contact 11 made of these metals is less susceptible to sulfur, and thus is less susceptible to sulfur. Can be provided.

  In addition, the weight ratio of palladium to ruthenium is 90% by weight of palladium (Pd) and 10% by weight of ruthenium (Ru). By blending inexpensive ruthenium with palladium, sliding contact 11 costs can be reduced. Moreover, combining ruthenium with palladium increases the hardness and improves the wear resistance. Further, by setting ruthenium to 10% by weight, it is possible to obtain a hardness that can be processed when the sliding contact is processed. Note that the weight ratio of palladium to ruthenium can be set in a range where palladium is 90% by weight or more and ruthenium is 10% by weight or less, and when high hardness is not required, for example, the sliding contact is It is good also as 100 weight% of palladium only.

The principal part front view of the liquid level detection apparatus of this invention. Sectional drawing of the principal part of the liquid level detection apparatus of the invention. The figure which attached the conventional liquid level detection apparatus to the fuel tank.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid level detection apparatus 2 Fuel tank 3 Mounting plate 4 Conductor pattern 5 Resistor 6 Insulating substrate 7,11 Sliding contact 8 Contact plate 9 Float 10 Arm

Claims (4)

In the liquid level detection device having a float that operates following the liquid level, a sliding contact that is interlocked with the movement of the float, and an insulating substrate that is provided with a conductor pattern on which the sliding contact slides, the sliding contact Is a liquid level detection device characterized by comprising only palladium. In the liquid level detection device having a float that operates following the liquid level, a sliding contact that is interlocked with the movement of the float, and an insulating substrate that is provided with a conductor pattern on which the sliding contact slides, the sliding contact Is made of an alloy of palladium and ruthenium. 3. The liquid level detection apparatus according to claim 2, wherein the weight ratio of palladium to ruthenium is 90 wt% or more of palladium and 10 wt% or less of ruthenium. 3. The liquid level detection apparatus according to claim 2, wherein the weight ratio of palladium to ruthenium is 90% by weight of palladium and 10% by weight of ruthenium.

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