JPH0815359A - Corrosion degree sensor - Google Patents

Abstract

PURPOSE:To detect the extent of corrosion of a switch contact accurately by causing a silver transition phenomenon depending on the moisture, water content, etc., between silver terminals provided in the housing of a switch. CONSTITUTION:A DC voltage is applied from a battery 12 to silver terminals 3, 4 on a resin board 5 and when the humidity in the housing 1 increases due to intrusion of moisture, silver transition phenomenon takes place through electrophoresis between the terminals 3, 4. Eventually, the terminals 3, 4 are conducted electrically and a current flows between them. A corrosion detector 13 sequentially accumulates the time interval when the current flows between the terminals 3, 4 and the number of times of silver transition phenomena. When the accumulated value exceeds a reference corrosion time of switch contact preset based on measurements, a decision is made that the mutually contacting or sliding switch contacts 2a, 2b are corroded and the fact is notified by means of a lamp. It is also true when water intrudes into the sensor but since the silver transition phenomenon is different relatively, the terminals 3, 4 are arranged optimally depending on the set reference value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a corrosion degree sensor for detecting a silver terminal when corrosion of metal of a switch contact due to infiltration of moisture into a switch housing.

[0002]

2. Description of the Related Art Conventionally, a pair of metal plates are arranged in a housing of a switch at regular intervals, and the intrusion of water into the housing is detected by an electrical short circuit between the metal plates. What to do is proposed.

Then, the corrosion degree of the switch contact in the switch can be predicted by measuring the number of detections of such an electrical short circuit and the cumulative detection time of the electrical short circuit state.

On the other hand, a humidity sensor is provided in the housing of the switch so that the humidity in the housing can be constantly monitored, and the housing is calculated by calculation based on the time when the humidity sensor detects a high humidity above a set level. It has also been proposed to determine the degree of corrosion of the switch contacts inside.

[0005]

However, in the method of predicting the degree of corrosion by the pair of metal plates described above, electrical conduction can be obtained unless water completely penetrates so as to short-circuit the metal plates. Therefore, it is not possible to detect the corrosion degree of the actual switch contact with high accuracy, and when the distance between the metal plates is narrow, the electrical conductivity of the electrical circuit may be reduced due to the condensation of the moisture in the air inside the housing due to the temperature change. There is a problem that the electrical conductivity is easily generated and the corrosion degree is detected although the switch contact is hardly corroded.

In addition, in the corrosion degree detecting method using the humidity sensor, in addition to the humidity sensor, the corrosion degree of the switch contact is calculated from the timer for measuring the detection time of high humidity exceeding the set level and the accumulated time of the time. Therefore, it is necessary to separately prepare a complicated arithmetic circuit required by, which causes a problem such as an increase in cost.

The present invention has been made by paying attention to the above-mentioned conventional problems, and by utilizing the silver migration phenomenon in the silver terminal, the switch contact inside the housing depending on the moisture and humidity inside the housing. An object of the present invention is to obtain a corrosion degree sensor which can correctly detect the corrosion degree.

[0008]

The corrosion sensor according to the present invention is arranged in the housing of the switch at a constant interval independently of the switch contacts, and is capable of causing a silver migration phenomenon due to infiltration of moisture. At least a pair of silver terminals are provided.

[0009]

In the corrosion sensor according to the present invention, by applying a DC voltage between the silver terminals provided in the housing of the switch, moisture, humidity, temperature,
Depending on the DC voltage, the insulation resistance of the substrate on which the silver terminal is provided, etc., a silver transfer phenomenon is caused in the silver terminal, and the accumulated time of conduction between the silver terminals due to this causes the switch contact of the switch contact in the housing. Get the degree of corrosion.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram showing a switch having a corrosion sensor according to the present invention. In the figure, reference numeral 1 is a switch housing, 2a and 2b are switch contacts provided in the housing 1 and turned on and off, Reference numerals 3 and 4 are a pair of silver terminals which are provided in the housing 1 together with these switch contacts 2a and 2b, and which are arranged at regular intervals.

The silver terminals 3 and 4 are formed on a resin substrate 5 as shown in FIGS. 2 and 3. The silver terminals 3 and 4 do not necessarily have to be provided on a resin substrate 5 prepared separately. If the housing 1 itself is made of synthetic resin, it may be deposited, coated or printed on the housing 1. Provision is optional. Furthermore, instead of the resin substrate 5, it is also possible to use a sheet material made of paper, wood, or other material whose insulation resistance is lowered by receiving moisture.

Reference numerals 6 and 7 denote a pair of connection terminal blocks provided on the resin substrate 5, to which the silver terminals 3 and 4 are connected via leads 8 and 9, respectively. Further, a battery 1 as a DC power source provided outside the housing 1 via leads 10 and 11 is connected to these connection terminal blocks 6 and 7.
2 and the corrosion detection device 13 are connected in series.

Next, the operation will be described. Silver terminals 3, 4
A DC voltage is constantly applied to the battery from the battery 12. When moisture enters the housing 1 and the humidity gradually increases, the insulation resistance of the resin substrate 1 also gradually decreases.

When the insulation resistance is greatly reduced, a silver migration phenomenon due to electrophoresis is caused between the silver terminals 3 and 4 on the resin substrate 1, and finally these silver terminals 3 and 4 are formed.
The areas are electrically connected. That is, each silver terminal 3, 4
The two are short-circuited and a current flows between them.

Therefore, in the corrosion detection device 13, the cumulative value of the time and the number of times the current flows is sequentially calculated, and the cumulative value exceeds the preset reference value of the corrosion time of the switch contact calculated based on the actual measurement value in advance. In this case, it is determined that the switch contacts 2a and 2b that are in contact with each other or slide with each other have been corroded, and the corrosive generation is notified by, for example, a lamp.

Further, the intrusion of water or water droplets into the housing 1 can be immediately detected by the corrosion detecting device by short-circuiting the silver terminals 3 and 4.

The silver migration phenomenon is caused by the moisture and humidity that have penetrated into the housing 1, the temperature, the DC voltage, and the insulating substrate 5.
It is desirable that the silver terminals 3 and 4 are optimally arranged in correspondence with the above-mentioned set reference values, since they are relatively different depending on the insulation resistance of the above.

In the above embodiment, the battery 12 is connected to the silver terminals 3 and 4, but the switch contact 2
Even if a series circuit of a rectifier (such as a diode), a corrosion detection device 13, and silver terminals 3 and 4 is connected in parallel with a and 2b, the same effect as that of the above-described embodiment is obtained.

If a large current does not flow through the switch contacts 2a and 2b and the switches are operated in an environment in which they are relatively resistant to corrosion, as shown in FIG. By connecting the resistor 15 in the DC circuit connecting the four, the corrosion detection current can be limited, and the detection sensitivity can be lowered, and thus the resistance can be arbitrarily adjusted.

Further, as shown in FIG. 5, another silver terminal 4A different from the above silver terminal 4 is separately arranged to face the silver terminal 3, and the distance between the silver terminal 3 and the silver terminal 4 and the silver terminal 4 are By making the distance between the terminal 3 and the silver terminal 4A different, the progress of corrosion of the switch contacts 2a and 2b can be determined stepwise from the corrosion detection current that changes based on the silver migration phenomenon.

Incidentally, the stepwise detection of the progress of such corrosion can be carried out with or without changing the distance between the silver terminal 3 and the silver terminals 4 and 4A, or by changing the distance. , 4A circuit has a significantly different limiting resistance 1
Even if 6, 7 are connected, the same effect as in the above embodiment can be obtained.

[0022]

As described above, according to the present invention, at least a switch contact is arranged in the housing of the switch at a constant interval independently of the switch contacts, and at least silver migration due to infiltration of moisture can occur. Since it is configured to provide a pair of silver terminals, the effect of being able to accurately detect the corrosion degree of the switch contact inside the housing depending on the moisture and humidity inside the housing by utilizing the silver migration phenomenon at the silver terminal There is.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a switch having a corrosion degree sensor according to an embodiment of the present invention.

FIG. 2 is a front view showing a main part of the corrosion degree sensor in FIG.

3 is a plan view showing a main part of the corrosion degree sensor in FIG. 1. FIG.

FIG. 4 is a conceptual diagram showing a corrosion degree sensor according to another embodiment of the present invention.

FIG. 5 is a conceptual diagram showing a corrosion degree sensor according to still another embodiment of the present invention.

[Explanation of symbols]

 1 Housing 2a, 2b Switch contact 3, 4, 4A Silver terminal 15, 16, 17 Resistance

Claims (1)

[Claims] 1. A corrosion degree sensor having at least a pair of silver terminals, which are arranged in a housing of a switch independently of a switch contact at regular intervals and which can cause a silver migration phenomenon due to infiltration of moisture.