KR20030060717A - Electrode compositions of Fuel Sender for automotible - Google Patents

Abstract

PURPOSE: Electrode composition for a fuel sender is provided to prevent malfunction of a fuel gauge by reducing a creation of an insulation layer through adding copper and cerium to electrode material of the fuel sender. CONSTITUTION: Copper and cerium are added to electrode material of a fuel sender having silver as main component, thereby preventing an insulation layer from being created on the fuel sender. Component of electrode material is adjusted in such a manner that a sulfuric compound layer causing a great contact resistance between an electrode and a contact of the fuel sender is prevented from being created on the fuel sender. That is, by adding copper and cerium to electrode material, erosion resistance against sulfuric component is increased and mechanical property and electric conductivity are properly maintained.

Description

Electrode compositions of Fuel Sender for automotible

The present invention relates to an electrode material composition of a fuel sender, and more particularly, copper and cerium are added to an electrode material of a fuel sender mainly containing silver, thereby reducing the formation of an insulating film, thereby reducing malfunction of the fuel gauge guide. An electrode material composition of a fuel sender to prevent sulfur corrosion.

The fuel amount indication of the vehicle fuel gauge is made by transmitting a variable electrical resistance value in a variable resistance circuit structurally connected with a float that interlocks along the oil level in the fuel tank to the cluster. Here, the float and the variable resistance circuit structurally connected to the float are called fuel senders. The variable resistor portion of the fuel sender is printed on the insulating ceramic substrate with a resistive material having a constant electric resistivity value, and an electrode having a structure electrically connected to the resistive material is used to detect the resistive value of the resistive material. Is printed above. In addition, the end of the rod connected to the float is fixed to the body on which the ceramic substrate is fixed, the fixed shaft is to be rotatable.

Therefore, when the float moves along the oil level of the fuel, the rod integrally connected with the float draws an arc around the fixed axis of the opposite end, and the contact is fixed to a part of the rod drawing the arc, It is energized by contact with the printed electrode.

The resistance value sent to the cluster is the resistance value of the circuit determined by the contact position between the electrode and the contact point determined by the fuel level.

The structure of the variable resistor portion is shown in FIG. 1, and the left side of the figure is the body of the fuel sender and the variable resistor portion (a ceramic substrate on which the resistor material and the electrode are printed) fixed thereto, and the right side is in sliding contact with these electrodes. This is the part where the contact is energized.

When the parts are operated, the left and right sides overlap each other, and the holes drilled at the bottom of both sides coincide with each other, and a rotation shaft connected to the float is inserted into this hole.

The variable resistor portion where the contacts and the electrodes are in contact with each other and is energized is located at the center portion inside the fuel tank, so as to be immersed in or exposed to the fuel, depending on the amount of fuel in the tank.

Generally, a silver (Ag) alloy system having excellent electrical conductivity is used as a material of a contact and an electrode, and silver-30 wt% palladium (Pd) alloy system is generally used.

Palladium is added to improve the mechanical properties of silver and to prevent corrosion by the sulfur (S) component in the fuel. When the amount of palladium added to the silver is more than 40% by weight, sulfur corrosion hardly occurs, but relative In order to reduce the electrical conductivity, a large amount of 20 to 30% by weight is used.

The contact is processed by melting the silver and palladium raw materials together and processing the alloyed material in the form of contacts.The electrodes must be printed on the ceramic substrate in a regular pattern. After printing on the substrate it is fixed to the ceramic substrate by heat treatment.

As described above, since the amount of palladium added to the silver is limited due to the decrease in the electrical conductivity, corrosion of the sulfur component occurs when the component elapses for a long time in the fuel.

Corrosion caused by the sulfur component occurs more severely at the positive electrode of the circuit structure, and as a result of this corrosion, a film of sulfur compound is formed on the surface of the electrode.

The component of the sulfur compound formed as a result of the corrosion is mainly silver sulfide (Ag ₂ S), and the film of silver sulfide is particularly poor in electrical conductivity.

When a film having a low electrical conductivity is formed on the surface of the electrode in contact with the contact, the contact resistance becomes very large, and thus a value different from the intended resistance value is displayed depending on the position of the contact with the contact, and is detected due to an increase in the contact resistance. As the resistance value increases, the signal sent from the cluster to the fuel gauge changes, resulting in an error where the instructions on the fuel gauge point to a location different from the current fuel amount.

In order to solve the above problems, attempts have been made to reduce the contact resistance by increasing from one point to two points in the prior art where the contact point and the electrode contact each other, but this method can also remove the insulating film generated on the electrode surface. There is no fundamental solution to the fuel gauge failure.

Therefore, the development of an efficient method for removing the insulating film as described above is urgently needed.

Thus, the inventors of the present invention, by adjusting the components of the electrode material made of silver and find that the addition of copper and cerium in an appropriate ratio instead of palladium can produce an electrode excellent in corrosion resistance to sulfur components to complete the present invention It was.

Accordingly, the present invention provides an electrode material composition of a fuel sender which prevents sulfur corrosion, which reduces the formation of an insulating film by adding copper and cerium to the electrode material of a fuel sender composed mainly of silver, thereby reducing the malfunction of the fuel gauge guidelines. The purpose is to provide.

1 is a photograph showing the structure of a vehicle fuel sender variable resistor unit.

The present invention is characterized by providing a fuel sender electrode material composition comprising 60 to 80% by weight of silver and 10 to 20% by weight of copper and 10 to 20% by weight of cerium in the fuel sender electrode material composition.

The present invention relates to an electrode material composition of a fuel sender which prevents sulfur corrosion by reducing copper film formation by adding copper and cerium to the electrode material of a fuel sender mainly composed of silver, thereby reducing the formation of an insulating film. The composition of the electrode material was adjusted so that a sulfur compound film that caused a large contact resistance between the electrode and the contact of the fuel sender was not formed on the electrode.

That is, by adding a specific element to the existing electrode material to increase the corrosion resistance to sulfur components, to maintain the mechanical properties and electrical conductivity at an appropriate level. In the present invention, the basic alloy component is designed as an alloy of silver (Ag) and copper (Cu) having excellent mechanical strength and electrical conductivity, and cerium (Ce), which is known to have excellent corrosion resistance to sulfur, is added to the alloy component. The hardness, electrical conductivity and corrosion resistance of sulfur were improved.

In the composition of the present invention, copper is used in an amount of 10 to 20% by weight, when less than 10% by weight is used, electrical conductivity is not good, and when used in excess of 20% by weight, a large amount of metal is eluted due to yellow corrosion. .

In addition, cerium is used in 10 to 20% by weight, when less than 10% by weight is used, the corrosion resistance by sulfur is poor, and a large amount of metal is eluted out, when used in excess of 20% by weight there is a problem that the electrical conductivity is lowered. .

Hereinafter, the present invention will be described in more detail with reference to the following examples, which are not intended to limit the present invention.

Examples 1-5 and Comparative Examples 1-9

Silver, palladium, copper and cerium powders were quantified in the corresponding composition, mixed with organic binder polyvinyl alcohol (Poly-Vinyl-Alcohol: PVA), printed on a ceramic substrate with a thickness of 30 to 50 μm, and reduced to about 700 ° C. Heat treatment in the atmosphere.

The content of the composition is shown in Table 1 below.

Test Example

The physical properties of the electrode specimens prepared from the compositions prepared according to the above Examples and Comparative Examples were measured, and the results are shown in Table 1 below.

The mechanical properties measured Vickers hardness (Hv) and the electrical conductivity measured IACS (%). In order to examine the resistance to sulfur corrosion, each specimen was immersed in dilute sulfuric acid (3%) for 5 minutes and the total concentration of the metal elements (Ag, Pd, Cu, Ce) eluted in sulfuric acid solution was measured. After the test, it was judged that the lower the concentration of the metal element eluted in the sulfuric acid solution, the better the corrosion resistance.

As shown in Table 1, in the case of the existing Ag-30 wt% palladium (Comparative Example 1) alloy, most of the metal eluted after the sulfur corrosion test was silver (Ag), and a very small amount of palladium was detected. This is due to the corrosion resistance of palladium to sulfur, and it can be seen that silver was eluted in spite of the reduced surface area that could be contacted with sulfur due to the added palladium.

On the other hand, when copper is added to silver, the hardness and electrical conductivity are generally improved, while the amount eluted by sulfuric acid is increased.

However, as the amount of cerium added increases, the electrical conductivity decreases, but the corrosion resistance against hardness and sulfur increases.

In particular, it can be seen that in Example 2 (silver-15 wt% copper-15 wt% cerium), the hardness, the electrical conductivity, and the corrosion resistance to sulfur are very excellent compared to the existing alloy.

As described above, the electrode made of the composition of the electrode material of the present invention is excellent in hardness, electrical conductivity, as well as corrosion resistance to sulfur as compared with the prior art can reduce the guide malfunction of the fuel gauge.

Claims (1)

A fuel sender electrode material composition comprising 60 to 80% by weight of silver as a main material and 10 to 20% by weight of copper and 10 to 20% by weight of cerium.