JPH078471U - Dew condensation prevention structure of electronic parts case - Google Patents

Abstract

(57) [Summary] [Purpose] In the case containing electronic parts such as human body detection sensor, the water content at the time of sealing is maintained,
When the environmental temperature decreases, dew condensation is likely to occur inside, and the internal circuit is short-circuited, and this is provided to provide a structure in which dew condensation is difficult to occur. In a system for detecting a user of a urinal and automatically cleaning the toilet, a desiccant 10 is stored in an electronic component case 1 in which electronic components such as a human body detection sensor 7 and a processing circuit thereof are stored.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a human body detection sensor such as an infrared sensor or a hand detection sensor, and a structure for preventing dew condensation in an electronic component case accommodating an electronic component such as a processing circuit thereof. It is used for electronic parts cases of controllers for automatic discharge of water.

[0002]

[Prior art]

 Conventionally, in a system toilet where a large number of urinals are installed side by side, a human body detection sensor such as an infrared sensor is arranged to prevent wasted use of washing water, and after detecting the toilet user. A system that controls the automatic cleaning at a fixed timing is used. The electronic components such as the human body detection sensor and its processing circuit are housed in a case attached to the upper wall of the urinal.

[0003]

[Problems to be solved by the device]

 However, in the conventional electronic component case that houses electronic components such as this type of human body detection sensor, once sealed at the time of manufacturing, the moisture content at the time of sealing is usually maintained to prevent dew condensation. However, there is a problem that when the environmental temperature decreases, the relative humidity rises, so that dew condensation easily occurs and the internal circuit short-circuits and fails. In addition, when the electronic component case is opened for maintenance such as repair and replacement of electronic components, there is a problem that the humidity in the toilet, which has a relatively high humidity, affects the moisture and makes dew condensation more likely. Such a problem also occurred in the case of the electronic component case of the controller for automatic discharge of hand washing water and warm air installed in the hand washing device.

[0004]

[Means for Solving the Problems]

 The dew condensation prevention structure of the electronic part case according to claim 1 of the present invention is such that the desiccant is contained in the electronic part case containing the electronic parts such as the human body detection sensor or the hand detection sensor and the processing circuit thereof. It is a structure.

According to a second aspect of the present invention, there is provided a dew condensation preventing structure for an electronic component case, wherein the desiccant in the device according to the first aspect has a characteristic that the water absorption rate at high humidity rapidly increases.

[0006]

[Action]

 Since the desiccant is stored in the electronic component case that houses the human body detection sensor or hand detection sensor, and its processing circuit, etc., the environment where the relative humidity rises and the environmental temperature drops and condensation is likely to occur Even if it becomes, the desiccant acts and does not cause dew condensation. This can prevent a short circuit failure of the internal circuit.

Furthermore, when a desiccant having a relatively high water absorption rate at high humidity is used, dew condensation can be completely prevented even when the case is opened for maintenance or the like.

[0008]

【Example】

 An embodiment of a dew condensation preventing structure for an electronic component case according to the present invention will be described below with reference to the drawings. FIG. 1 is a partially cutaway side view of a case having a dew condensation preventing structure for an electronic component case according to the present invention. The electronic component case 1 is, for example, a case of a controller of an automatic urinal cleaning device, which is embedded in a recess 3 at an upper position of a wall surface 2 on which a urinal is installed. A rubber bush (not shown) provided on the back side of the case 1 is used to drive and control an AC100V power cord for introducing an external power source into the case 1 and a solenoid valve for cleaning the urinal. The control code for outputting the control signal of is wired.

The power cord is wired to a power substrate 4 which is provided upright on the back side of the case 1. On the power supply board 4, a power supply circuit element for converting an AC voltage into a DC voltage for driving an electronic circuit is mounted. DC power is supplied from the power supply board 4 to the sensor board 6 via the wiring 5.

A human body detection sensor 7 and its signal processing circuit are mounted on the sensor substrate 6. That is, the sensor substrate 6 detects, for example, a projector, a light receiver, and a change in the amount of reflected light detected by the light receiver, which constitutes an infrared sensor for detecting a human body according to the amount of reflected light of infrared rays. Mounted are the electronic components that make up the processing circuit for outputting the results of human body detection. The sensor board 6 is arranged at an oblique position, and is projected obliquely downward from the projector as indicated by an arrow 8, whereby the human body in front of the urinal can be detected. ing.

A frame body 9 having a “U” -shaped cross section is attached to the inner surface of the case 1 at an upper position on the back side in the case 1. The desiccant 10 is stored in the frame 9. The desiccant 10 is, for example, a silica gel bag, and its amount is present when the inside of the case 1 is a closed type and the humidity is 100% and the temperature is 40 ° C. A silica gel that can sufficiently absorb the amount of water vapor in the inside may be used.

For example, as the desiccant 10, silica gel A type and B type manufactured by Fuji Co., Ltd. are used. Here, silica gel type A is excellent in water absorption at low humidity, while type B is particularly excellent in water adsorption capacity at high humidity, and particularly type B has coarsely continuous particles. Because of the large diameter, it has a large pore volume and absorbs water by capillarity. For this reason, type B has a lower water absorption than type A when the humidity is low, but when the relative humidity is above 60 percent, the rate of water absorption is greater than that of type A, and from an environment of 70 percent or higher. Has the characteristic that this water absorption rate increases rapidly.

The case 1 is usually a closed type, but when it is necessary to open and close the case 1 for adjustment, repair, etc. of electronic parts such as an infrared sensor, the case 1 is protected from the ambient environmental humidity. Even if it is affected by high humidity, the water absorption rate of the silica gel B type increases sharply at high humidity, so water can be sufficiently absorbed without increasing the amount of the desiccant 10. Is more preferred than silica gel type A.

Although a large number of electronic circuit elements are arranged on the power supply board 4 and the sensor board 5 in the case 1, since the desiccant 10 is stored in the case 1, the environmental temperature is temporarily lowered. As a result, even if dew condensation easily occurs, no dew condensation will occur. When the desiccant 10 having the characteristic that the water absorption rate rapidly increases at high humidity, such as the above-mentioned silica gel B type, when the inside humidity becomes high when the case 1 is opened for maintenance or the like, that much becomes so. Condensation can be completely prevented as the amount of adsorption increases.

In the above-mentioned embodiment, the case of the controller for automatic cleaning of the urinal is described, but in addition, for the automatic discharge of the hand-washing water of the hand-washing device which houses the hand detection sensor and its processing circuit, or the temperature. The same applies to the electronic component case of the controller for automatic wind blowing.

[0016]

[Effect of device]

 As described above, according to the present invention, it is possible to prevent dew condensation in an electronic component case accommodating an electronic component such as a human body detection sensor or a hand detection sensor and a processing circuit thereof. Therefore, it is suitable for the case structure of the automatic cleaning controller of the urinal and the automatic discharge controller of the hand washing device, and can effectively prevent the short circuit failure of the internal circuit.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view showing a dew condensation preventing structure of an electronic component case according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Case (electronic component case) 4 ... Power supply board 6 ... Sensor board 7 ... Human body detection sensor 9 ... Frame body 10 ... Desiccant

Claims (2)

[Scope of utility model registration request] 1. A human body detection sensor or a hand detection sensor,
Also, a dew condensation preventing structure for an electronic component case, characterized in that a desiccant is stored in the electronic component case that stores electronic components such as a processing circuit thereof. 2. The dew condensation preventing structure for an electronic component case according to claim 1, wherein the desiccant has a characteristic that a water absorption rate at high humidity rapidly increases.