JP2008282361A - Electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide electronic equipment for preventing water from being accumulated in a resonant cavity without lowering sound pressure. <P>SOLUTION: An alarm generation part 2 comprises: a piezoelectric vibrating plate 3 placed to face an inner surface of a front wall part 10; a nearly cylindrical projection wall part 4 which projects backwards from the inner surface of the front wall part 10 and composes a resonant cavity 5 comprising a space surrounded by the piezoelectric vibrating plate 3 and the front wall part 10; and a plurality of sound release holes 6a and 6b which are bored through the front wall part 10 to release vibration sounds from the piezoelectric vibrating plate 3 to the outside and discharge drain water inside the resonant cavity 5. One of the sound release holes 6a has a lower end part on an inner surface continuously integrated with an inner surface below the resonant cavity 5, while the other sound release hole 6b has an upper end part on the inner surface continuously integrated with an inner surface above the resonant cavity 5. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electronic device that generates a notification sound by being fixed to a construction surface.

2. Description of the Related Art Conventionally, electronic devices that are attached and fixed to a construction surface such as a wall surface and generate a notification sound are known. For example, an alarm device that detects breakage of a window glass is provided. This type of alarm device has an anomaly detection circuit including a piezoelectric ceramic (not shown) and a filter circuit (not shown) that separates a frequency component related to breakage of the window glass from the output of the piezoelectric ceramic, It is affixed to the window glass so that the vibration of the window glass is transmitted to the piezoelectric ceramic, and breakage of the window glass is detected based on the output of the filter circuit. When an abnormality is detected, the abnormality detection circuit generally drives a piezoelectric buzzer to sound an alarm sound. As a piezoelectric buzzer used in such an alarm device, for example, it is disclosed in Patent Document 1. There is something. This type of piezoelectric buzzer has a substantially cylindrical protruding wall portion protruding rearward from the inner surface of the front wall portion of the device main body, the rear wall portion being installed on a construction surface parallel to the vertical direction, and a protruding wall A resonance chamber is formed by a space surrounded by the piezoelectric diaphragm, the projecting wall section, and the front wall section, and a sound emitting hole that emits vibration sound from the piezoelectric diaphragm to the outside It is formed by penetrating substantially the center of the wall. Thus, when an electrical signal from the abnormality detection circuit is input to the piezoelectric diaphragm, the piezoelectric diaphragm vibrates, the vibration sound is resonantly amplified in the resonance chamber, and a notification sound is emitted to the outside through the sound emitting hole. It is supposed to be.
Japanese Patent No. 2946260

  However, in the above conventional example, when installed outdoors or in a place with high humidity, there is no means for discharging water to the outside of the resonance chamber even if water enters from the sound emission hole due to rain or condensation, and the resonance chamber There was a possibility that water accumulated in the interior of the chamber, causing a decrease in sound pressure. In addition, there is a possibility that the sound emission hole is blocked by condensation or freezing of the water inside the resonance chamber due to a decrease in temperature, causing a rapid decrease in sound pressure.

  The present invention has been made in view of the above points, and an object of the present invention is to provide an electronic device that can prevent water from collecting in a resonance chamber without reducing sound pressure.

  In order to achieve the above object, the invention of claim 1 is a substantially box-shaped device main body whose rear wall is attached and fixed to a construction surface parallel to the vertical direction, and a front wall of the device main body housed in the device main body. An electronic device including a notification sound generating unit that emits a notification sound from the unit, wherein the notification sound generating unit includes a piezoelectric diaphragm disposed opposite to the inner surface of the front wall portion of the device main body, A substantially cylindrical projecting wall portion that projects from the inner surface of the front wall portion toward the rear and forms a resonance chamber that is surrounded by the piezoelectric diaphragm and the front wall portion of the device body, and the front wall of the device body And a plurality of sound emission holes for discharging vibration sound from the piezoelectric diaphragm to the outside and discharging water in the resonance chamber, and one of the at least two sound emission holes is The lower end portion of the inner peripheral surface is formed integrally with the vertically lower surface of the resonance chamber so as to be flat with the vertically lower surface of the resonance chamber. Alternatively, the other sound emitting hole is inclined so as to be inclined vertically downward from the vertically lower surface of the resonance chamber, and the upper end portion of the inner peripheral surface thereof is formed continuously and integrally with the vertically upper surface of the resonance chamber. It is characterized in that it is parallel to the vertical upper surface of the chamber, or is inclined vertically upward from the vertical upper surface of the resonance chamber.

  According to the present invention, one of the sound emitting holes is formed such that the lower end portion of the inner peripheral surface thereof is integrally formed with the vertically lower surface of the resonance chamber and is parallel to the vertically lower surface of the resonance chamber or vertically below the resonance chamber. Since it is inclined vertically downward from the surface of the surface, it is possible to prevent water from entering the resonance chamber due to rain, condensation, etc. to the minimum, even if water enters the resonance chamber, Since the water accumulated in the resonance chamber can be easily discharged from the sound emission hole, it is possible to prevent a decrease in sound pressure. In addition, the other sound emitting hole is formed such that the upper end portion of the inner peripheral surface thereof is continuously integrated with the vertically upper surface of the resonance chamber, and is parallel to the vertically upper surface of the resonance chamber or more than the vertically upper surface of the resonance chamber. Since it is inclined vertically upward, the sound emission hole is arranged vertically downward even when the device body is turned upside down by 180 degrees, thus preventing water from entering the resonance chamber to the minimum. In addition, the water accumulated in the resonance chamber can be easily discharged from the sound emission hole. Furthermore, since the sound emitting hole located vertically above depending on the mounting direction of the device main body serves as a vent hole, the water accumulated in the resonance chamber can be more easily discharged.

  Hereinafter, an embodiment in which the technical concept of the present invention is applied to an alarm device described in the prior art will be described with reference to the drawings. In the following description, the vertical and horizontal directions in FIG. 1B are defined as the vertical and horizontal directions, the front side of the paper is defined as the front direction, and the back side of the paper is defined as the rear direction. In the present embodiment, as shown in FIG. 1A, the apparatus main body 1 in which the rear wall portion 11 is attached and fixed to a construction surface (not shown) parallel to the vertical direction such as a wall surface, and the apparatus main body 1 is housed. And a notification sound generator 2 that emits a notification sound from the front wall 10 of the device main body 1. In addition, since this embodiment is an alarm device which sounds a notification sound when the breakage of the window glass is detected, in this embodiment, the device body 1 is attached and fixed to the window glass.

  As shown in FIGS. 3A and 3B, the device main body 1 includes a substantially box-shaped long body 1a having an open front surface and a substantially box-shaped long cover 1b having a rear surface opened. The body 1a and the cover 1b are both made of a thermoplastic resin such as ABS resin or polycarbonate resin. In the body 1a, a fusion conductive wire A made of a thin metal wire is accommodated in a groove (not shown) provided on the entire periphery thereof, and the cover 1b has the above-described body 1a on the body 1a. A protrusion B to be inserted into the groove is provided. Thus, the opening surfaces of the body 1a and the cover 1b are brought into contact with each other, and the fusion conductive wire A is energized with the projection B of the cover 1b inserted into the groove of the body 1a. The thermoplastic resin constituting the body 1a and the cover 1b is melted by the Joule heat generated by the resin, and the melted thermoplastic resin is cured after the energization is stopped, whereby the body 1a and the cover 1b are bonded to each other.

  Inside the device main body 1, a printed wiring board 7 on which an abnormality detection circuit (not shown) for detecting breakage of the window glass is mounted, a battery 8 for supplying power to the abnormality detection circuit, and an abnormality detection circuit are abnormal. And a notification sound generating unit 2 that sounds a notification sound when it is detected. The abnormality detection device is the same as that described in the conventional example and is well known, so detailed description thereof will be omitted here. The printed wiring board 7 is provided with a substantially circular fitting hole 7a having substantially the same diameter as a later-described protruding wall portion 4 of the notification sound generating portion 2, and the protruding wall portion 4 is provided in the fitting hole 7a. Is designed to fit. The cover 1b is provided with a battery opening 9 through which the battery 8 passes when the battery 8 is inserted into and removed from the device main body 1, and a battery cover 8a for closing the battery opening 9 is detachably attached. It is supposed to be.

  As shown in FIG. 1A, the notification sound generating unit 2 includes a piezoelectric diaphragm 3 disposed to face the inner surface of the front wall portion 10 (thickness 6 mm) of the device main body 1, and the front wall of the device main body 1. A substantially cylindrical protruding wall portion 4 that constitutes a resonance chamber 5 that is configured to protrude rearward from the inner surface of the portion 10 and is surrounded by the piezoelectric diaphragm 3 and the front wall portion 10 of the device main body 1; A plurality of (two in the figure) sound emitting holes 6a and 6b that are provided in the front wall portion 10 of the main body 1 to discharge the vibration sound from the piezoelectric diaphragm 3 to the outside and discharge the water inside the resonance chamber 5; Consists of.

  The piezoelectric diaphragm 3 has a substantially circular diaphragm 3b (diameter of 20 mm, thickness of 0.1 mm) made of a metal such as brass on one surface of a piezoelectric ceramic plate 3a sandwiched between two electrodes (not shown). 42 mm) is attached, and lead terminals (not shown) are respectively attached to the diaphragm 3b and the electrodes provided on the other surface of the piezoelectric ceramic plate 3a. Thus, when the electrical signal is input to the lead terminal, the piezoelectric diaphragm 3 vibrates, and the vibration sound is resonantly amplified in the resonance chamber 5 and emitted to the outside from the sound emitting holes 6a and 6b.

  The sound emitting holes 6a and 6b have a substantially circular cross section, and are respectively provided in the front and rear directions on the upper side and the lower side of the front wall portion 10 of the device body 1 as shown in FIG. . The lower end portion of the inner peripheral surface of the sound emitting hole 6a is formed continuously and integrally with the inner peripheral surface below the resonance chamber 5, and the upper end portion of the inner peripheral surface of the sound emitting hole 6b is an inner portion on the upper side of the resonance chamber 5. It is integrally formed with the peripheral surface. The sound emitting holes 6a and 6b are both formed with substantially the same diameter (1.5 mm in diameter).

  With the configuration as described above, when the apparatus main body 1 is mounted and fixed on the construction surface so that the sound emission hole 6a is disposed on the lower side, water infiltrates into the resonance chamber 5 due to rain or condensation. Since the water accumulated in the resonance chamber 5 can be easily discharged from the sound emission hole 6a even if water enters the resonance chamber 5, the sound pressure is reduced. Can be prevented. Further, even when the apparatus main body 1 is attached and fixed to the construction surface so that the sound emission hole 6b is disposed on the lower side, water in the resonance chamber can be discharged from the sound emission hole 6b, and the sound emission hole 6a. Since it plays the role of a vent hole, water can be easily discharged.

  In the present embodiment, the inner peripheral surfaces of the sound emitting holes 6a and 6b are flush with the upper and lower inner peripheral surfaces of the resonance chamber 5, respectively, but as shown in FIG. The lower end portion of the inner peripheral surface of the sound emitting hole 6a is inclined downward from the inner peripheral surface below the resonance chamber 5, and the upper end portion of the inner peripheral surface of the sound emitting hole 6b is inclined from the inner peripheral surface above the resonance chamber 5. Also, it may be configured to be inclined upward. In this case, the water inside the resonance chamber 5 can be more easily discharged by the inclination.

  In the above embodiment, the sound emitting holes 6a and 6b having substantially the same diameter are provided at the upper end and the lower end of the front wall portion 10, but as shown in FIG. 2A, the sound emitting holes 6a and 6b are provided. May be formed with different diameters. In FIG. 2A, the diameter of the lower sound emitting hole 6a (diameter 2.75 mm) is larger than the diameter of the upper sound emitting hole 6b (diameter 0.25 mm). When the device main body 1 is mounted and fixed on the construction surface so that the hole 6a is disposed on the lower side, the upper sound emitting hole 6b serves as a vent hole, and it is easy to discharge water from the sound emitting hole 6a. Can do.

  Further, as shown in FIG. 2 (b), sound emitting holes 6c and 6d are respectively provided at the left and right ends of the substantially central portion of the front wall portion 10 in the vertical direction (the diameter of each of the sound emitting holes 6a to 6d is 0.75 mm). May be provided. The sound emitting holes 6c and 6d have a substantially circular cross section, and are provided in the front and rear directions on the left and right sides of the front wall portion 10 of the device main body 1, respectively. The left end portion of the inner peripheral surface of the sound emitting hole 6c is formed integrally with the inner peripheral surface on the left side of the resonance chamber 5, and the right end portion of the inner peripheral surface of the sound emitting hole 6d is the inner periphery on the right side of the resonance chamber 5. It is formed integrally with the surface. In this case, even when the apparatus main body 1 is installed on the construction surface so that the left-right direction of the front wall portion 10 is parallel to the vertical direction, the sound emission holes 6c, 6d have the same effect as the sound emission holes 6a, 6b. Since it plays, the freedom degree of installation of the apparatus main body 1 with respect to a construction surface can be improved.

  In addition, the notification sound generation part 2 of this embodiment is not limited to the application to the alarm device which detects the breakage of the window glass, but can be used for other purposes as long as the device main body is attached and fixed to the construction surface. Needless to say, the present invention can also be applied to other electronic devices.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows embodiment of the electronic device of this invention, (a) is a principal part side view, (b) is a principal part front view, (c) is the case where the inner peripheral surface of a sound emission hole is inclined. It is a principal part side view. It is a figure which shows other arrangement | positioning of a sound emission hole same as the above, (a) is a front view which shows the case where each sound emission hole is made into a mutually different diameter size, (b) is the case where four sound emission holes are penetrated. FIG. It is a figure which shows an apparatus main body same as the above, (a) is a rear view which shows a cover, (b) is a front view which shows a body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Apparatus main body 10 Front wall part 11 Rear wall part 2 Notification sound generation part 3 Piezoelectric diaphragm 4 Projection wall part 5 Resonance chamber 6a, 6b Sound emission hole

Claims (1)

  A substantially box-shaped device main body whose rear wall portion is attached and fixed to a construction surface parallel to the vertical direction, and a notification sound generating portion that is housed in the device main body and emits a notification sound from the front wall portion of the device main body. In the electronic device, the notification sound generating unit is provided with a piezoelectric diaphragm arranged to face the inner surface of the front wall portion of the device main body, and a piezoelectric sound projecting rearward from the inner surface of the front wall portion of the device main body. A substantially cylindrical protruding wall that forms a resonance chamber composed of a space surrounded by the diaphragm and the front wall of the device main body, and a vibration sound from the piezoelectric diaphragm that passes through the front wall of the device main body And a plurality of sound emitting holes for discharging water in the resonance chamber, and one of the at least two sound emitting holes has a lower end portion of an inner peripheral surface thereof vertically below the resonance chamber. It is formed integrally with the surface and is parallel to the surface below the resonance chamber vertically or vertically below the surface below the resonance chamber. The other sound emitting hole is formed so that the upper end portion of the inner peripheral surface thereof is continuously integrated with the vertically upper surface of the resonance chamber and is parallel to the vertically upper surface of the resonance chamber or the vertical of the resonance chamber. An electronic apparatus characterized by being inclined vertically upward from an upper surface.

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