JP2007124200A - Mounting structure for piezoelectric diaphragm - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mounting structure for a piezoelectric diaphragm capable of reducing the number of mounting parts, and maintaining an appropriate contact status between the piezoelectric diaphragm and a cavity. <P>SOLUTION: A mounting structure 90 for the piezoelectric diaphragm maintains a piezoelectric diaphragm 11 having a piezoelectric element 11b formed on one surface side of a plate 11a between a housing 50 (75) of an electronic apparatus 10 and a cover member 20 having a cavity 21 which resonates with the piezoelectric diaphragm. Associating portions 26 and 92 are formed at each of the housing and the cover member, as a joint structure 91 for connecting the housing and the cover member each other. The associating portions 26 and 92 are disposed at a position relationship that obstructs movement in the direction where the housing and the cover member separate from each other by a slide operation of the cover member. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an attachment structure when a piezoelectric diaphragm is attached to a casing of an electronic device.

The piezoelectric diaphragm is generally stored in a case body for generating resonance and distributed as an electronic buzzer. The case body has a cylindrical portion whose one end is closed and the other end is open. A piezoelectric diaphragm is attached to the open end portion so as to cover and close the open end portion, and a sound is generated on the closed end portion side. Sound emitting holes are formed.
And when attaching such a piezoelectric diaphragm to an electronic device, it is screwed to the housing wall surface of the electronic device using a screw insertion hole of a mounting seat provided on the outer periphery of the case body (for example, a patent Reference 1).
Japanese Utility Model Publication No. 4-78895

However, in the above prior art, there is a problem in that a set screw is required for attachment to an electronic device, and the number of parts increases.
Further, there is a problem that the screwing work is required and the mounting work is complicated.
Further, in the above-described prior art, the case body may bend due to the fastening of the screw, and as a result, the contact state between the cylindrical portion of the case body and the piezoelectric vibration plate fluctuates and does not become, for example, a planned sound pressure. Etc., there was a possibility that it would not sound properly.

An object of the present invention is to reduce the number of parts required for mounting the piezoelectric diaphragm.
Another object of the present invention is to simplify and facilitate the operation of attaching the piezoelectric diaphragm.
Another object of the present invention is to maintain an appropriate contact state with the structure for causing resonance with the piezoelectric diaphragm.

  According to the first aspect of the present invention, a piezoelectric diaphragm in which a piezoelectric element is formed on one side of a flat plate is held between a housing of an electronic device and a cover body having a cavity that resonates with the piezoelectric diaphragm. As a connecting structure portion for connecting the casing and the cover body to each other, the casing and the cover body can be connected to each other by sliding the cover body. A configuration is adopted in which a facing portion is formed that has a positional relationship that prevents movement in a separating direction.

In the above configuration, the piezoelectric diaphragm is attached by connecting the cover body to the casing wall surface using the connecting structure portion in a state where the piezoelectric diaphragm is disposed between the wall surface of the casing and the cover body.
The connection structure portion includes a facing portion formed on the housing side and a facing portion formed on the cover body side. In the mounting operation, when the cover body is slid and moved from a state where the facing parts do not face each other, the cover body faces each other, and when the cover body is moved away from the housing, the arrangement is prevented. It has become. That is, the facing portion of the housing is positioned in the separation direction of the facing portion of the cover body. Thereby, unless the cover body is operated in the direction opposite to the slide operation direction, the cover body is not separated from the casing, and the connected state is maintained.
The slide operation direction is preferably not coincident with the direction in which the cover body and the casing are separated from each other, and more preferably in the direction orthogonal to the separation direction. Further, it is desirable that the slide operation direction is a direction in which the cover body is slid along the housing wall surface.
Further, the slide operation direction is not limited to the linear direction, and may be a curved direction or a rotational direction.

The invention described in claim 2 has the same configuration as that of the invention described in claim 1, and at least one of the facing portions of the housing or the cover body has an inclined surface inclined with respect to the sliding operation direction of the cover body. , Is adopted.
In the above configuration, by providing an inclined surface in at least one of the housing and the cover body, the transition from the non-facing state to the facing state is smoothly performed along the inclined surface by a slide operation.
It is desirable that the inclined surface is inclined so as to guide the opposing portion of the counterpart in a positional relationship that prevents movement in a direction in which the housing and the cover body are separated from each other during movement by the slide operation.

The invention described in claim 3 has the same configuration as that of the invention described in claim 1 or 2, and as a connecting structure portion, at least one of the housing or the cover body is moved to the cover body or the housing by a sliding operation. The stopper is formed so as to prevent the return movement of the facing portion.
In the above configuration, by providing a stopper on at least one of the housing and the cover body, the movement of the cover body or the facing portion on the housing side from the facing state to the non-facing state is restricted, and the cover body is attached to the housing State is maintained.

According to a fourth aspect of the present invention, there is provided a contact portion that has the same configuration as that of the first aspect of the present invention and that is in pressure contact with the piezoelectric diaphragm in a connected state of the housing and the cover body. Is provided on both the housing and the cover body.
In the above configuration, since the contact portion that presses against the piezoelectric diaphragm is provided on both the housing and the cover body, the piezoelectric diaphragm is held in a sandwiched state between the housing and the cover body, and stable holding is performed. Is called.

  According to a fifth aspect of the present invention, there is provided a piezoelectric device for holding a piezoelectric diaphragm having a piezoelectric element formed on one side of a flat plate between a housing of an electronic device and a cover body having a cavity that resonates with the piezoelectric diaphragm. A structure for attaching a diaphragm, comprising a connecting structure part for connecting the casing and the cover body to each other, comprising a plurality of plate-like parts formed integrally with the cover body, and adjacent to each other A configuration is adopted in which reinforcing ribs formed integrally with the respective plate-like portions are provided at the boundaries of the plate-like portions.

In the above configuration, the piezoelectric diaphragm is attached by connecting the cover body to the casing using the connecting structure portion in a state where the piezoelectric diaphragm is disposed between the wall surface of the casing and the cover body.
Further, since the reinforcing rib is provided at the boundary between two adjacent plate-like portions among the plurality of plate-like portions constituting the cover body, at least the crossing angle of the plate-like portions is maintained by the reinforcing rib. The Therefore, even when an external force is applied to the cover body when it is attached to the housing, it is possible to suppress the occurrence of bending and distortion, and thereby contact between the cavity and the piezoelectric diaphragm when the cover body is attached. State fluctuations or abnormalities are suppressed.
The reinforcing rib is a flat plate-like structure that faces in a direction intersecting with any of the two plate-like portions, and has a direction perpendicular to or close to both of the two plate-like portions. It is desirable.

The invention according to claim 6 has the same configuration as that of the invention according to claim 5, and the cover body is bent as a plate-like portion to a leg portion extending to the housing side and the tip of the leg portion. It is provided with an engaging portion that is provided and engages with the housing, and a reinforcing rib is provided between the leg portion and the engaging portion.
In the above configuration, the leg portion of the cover body is directed to the housing side, and the cover body is coupled to the housing by the engaging portion formed at the tip thereof.
Further, since the reinforcing rib is provided between the leg portion and the engaging portion, the bending and deformation of the leg portion and the engaging portion are suppressed during the connecting operation of the cover body and the housing and further after the connecting operation. In addition, fluctuations or abnormalities in the contact state between the cavity and the piezoelectric diaphragm are suppressed.

  The invention according to claim 7 has the same configuration as that of the invention according to any one of claims 1 to 6, and the cover body includes a small-diameter cylindrical portion that forms a hollow portion, and one end portion of the small-diameter cylindrical portion. The circular flat plate portion facing the piezoelectric vibration plate and having a sound emitting hole, the large-diameter cylindrical portion surrounding the piezoelectric vibration plate, and the annular flat plate portion connecting the cylindrical portions are integrally formed, and the cover body A configuration is adopted in which reinforcing ribs formed integrally with the small-diameter cylindrical portion and the annular flat plate portion are provided at the boundary between the small-diameter cylindrical portion and the annular flat plate portion on the outside.

  In the above configuration, since the reinforcing rib is provided between the small-diameter cylindrical portion and the annular flat plate portion, the small-diameter cylindrical portion and the annular flat plate portion are bent and deformed during the connection operation between the cover body and the casing. Is suppressed, and fluctuations or abnormalities in the contact state between the cavity and the piezoelectric diaphragm are suppressed.

The invention described in claim 8 has the same configuration as that of the invention described in claim 7, and is provided inside the cover body and at the boundary between the large diameter cylindrical portion and the annular flat plate portion. The reinforcement rib formed integrally with the part is provided.
In the above configuration, since the reinforcing rib is provided between the large-diameter cylindrical portion and the annular flat plate portion, the bending of the large-diameter cylindrical portion and the annular flat plate portion is further performed during the connection operation between the cover body and the housing. Deformation is suppressed, and fluctuations or abnormalities in the contact state between the cavity and the piezoelectric diaphragm are suppressed.

According to the first aspect of the present invention, a cover body having a cavity for causing resonance and a facing portion formed integrally with the housing are provided, and the housing and the cover body are connected to each other by the facing portions. Since the piezoelectric diaphragm is held, it is possible to eliminate the need for a set screw and to reduce the number of parts as in the prior art. Further, since the cover body serves as both means for causing resonance and means for holding the piezoelectric diaphragm, the number of parts can be further reduced.
Furthermore, since the cover body is attached to the housing by the connecting structure portion by the sliding operation of the cover body, complicated work such as screwing can be eliminated, and the piezoelectric diaphragm mounting work can be simplified and speeded up. It becomes possible.

  According to the second aspect of the present invention, since at least one of the facing portions of the housing or the cover body has an inclined surface, the transition from the non-facing state to the facing state by the sliding operation is smoothly performed, and the piezoelectric diaphragm It is possible to further simplify and smooth the mounting operation.

  In the invention according to claim 3, since the stopper is provided in at least one of the housing and the cover body, the movement of the cover body or the facing portion on the housing side to the non-opposing state is restricted, and the cover for the housing is covered. It is possible to maintain the body wearing state, maintain the holding state of the piezoelectric diaphragm, and suppress accidental disconnection.

  According to the fourth aspect of the present invention, since the contact portion that press-contacts the piezoelectric diaphragm in a connected state of the housing and the cover body is provided, the piezoelectric diaphragm is sandwiched between the housing and the cover body, and the piezoelectric is stably The diaphragm can be held.

  In the invention according to claim 5, since the reinforcing rib is provided at the boundary between the plate-like portions adjacent to each other in the cover body, each plate can be used even when receiving an external force when the cover body is attached to the housing. The crossing angle of the shape portions is maintained by the reinforcing ribs, and the occurrence of bending and distortion of the cover body is suppressed. Therefore, fluctuations or abnormalities in the contact state between the cavity and the piezoelectric diaphragm when the cover body is mounted are suppressed, and an appropriate contact state between the cavity and the piezoelectric diaphragm is maintained, and sound due to resonance of the piezoelectric diaphragm is maintained. It is possible to generate properly and appropriately.

  In the invention according to claim 6, since the reinforcing rib is formed between the leg portion and the engaging portion of the cover body that connects the cover body and the housing, Bending / deformation between the leg and the engaging part after connection is suppressed, and the proper contact state between the cavity and the piezoelectric diaphragm is more effectively maintained, and sound generation due to resonance of the piezoelectric diaphragm is better. It is possible to carry out properly.

  Since the reinforcing rib is formed between the small-diameter cylindrical portion and the annular flat plate portion of the cover body, the small-diameter cylindrical portion and the annular shape at the time of connecting the cover body and the housing and after the connection are formed Bending and deformation with the flat plate part is suppressed, and the proper contact state between the cavity part and the piezoelectric diaphragm can be more effectively maintained, and sound can be generated more appropriately and appropriately due to resonance of the piezoelectric diaphragm. It becomes.

  In the eighth aspect of the invention, since the reinforcing rib is formed between the large-diameter cylindrical portion and the annular flat plate portion of the cover body, the large-diameter cylindrical portion during and after the connection between the cover body and the casing. Bending and deformation between the plate and the annular flat plate part are suppressed, and the proper contact state between the cavity part and the piezoelectric diaphragm is more effectively maintained, and sound generation due to resonance of the piezoelectric diaphragm is performed more appropriately and appropriately. Is possible.

(Overall configuration of fire alarm)
A fire alarm device 10 according to an embodiment of the present invention will be described with reference to FIGS. 1 is a perspective view showing the front side of the fire alarm 10, FIG. 2 is a perspective view showing the back side, and FIG. 3 is an exploded perspective view.
The fire alarm 10 is installed on an indoor ceiling or wall surface of a building, and performs alarm notification by detecting smoke generated by a fire.
Here, in the following description, when the fire alarm 10 is installed, the plane facing the ceiling or wall surface of the building is the rear surface of the fire alarm 10, and the opposite surface is the front of the fire alarm 10. And
In the following description, the direction toward the front side will be described as the front, and the direction toward the back side will be described as the rear.

As shown in FIG. 3, the fire alarm 10 includes a smoke detection means 45 (see FIG. 6) that detects smoke when a fire occurs, a dark box 30 that stores the smoke detection means 45, and the smoke detection means 45. A circuit board 40 mainly including a circuit for sounding the piezoelectric diaphragm 11, a housing 50 incorporating the above-described components, and a mounting structure 90 for attaching the piezoelectric diaphragm 11 in the housing 50 are provided. Yes.
Hereinafter, each part will be described in detail.

(Casing)
FIG. 4 is a cross-sectional view of the fire alarm 10 taken along line XX shown in FIG. The housing 50 will be described with reference to FIGS.
As shown in FIGS. 3 and 4, the housing 50 mainly includes a circular base body 60 located on the back side, a circular housing cover 70 located on the front side, and the base body 60 and the housing cover 70. And a partition plate 75 that divides the interior of the housing 50 into two areas on the front side and the back side.

The housing cover 70 includes a circular front portion 71, a cylindrical portion 72 that forms a side wall surface that extends from the peripheral portion of the front portion 71, and a substantially cylindrical convex portion 73 provided at the center of the front portion 71. These are made by integral molding with a white resin material.
The convex portion 73 is arranged concentrically with respect to the front portion 71 and has a dish-shaped top plate 73a having a smaller diameter than the front portion 71, and four ribs 73b connecting the top plate 73a and the front portion 71. And have.

  Four ribs 73b are provided at regular intervals at the peripheral edge of the top plate 73a, and the ribs 73b are widely open. As shown in FIG. 4, the dark box 30 for storing the smoke detecting means 45 is disposed inside the convex portion 73, so that smoke can be generated in the dark box 30 by making the openings 73 c between the ribs 73 b. The structure is easy to guide.

  The top plate 73a is provided with an operation display portion 73d which is a circular through hole at the center position thereof. The operation indicator 73d is fitted with a light guide member 12 that transmits red light of the LED 41 provided on the circuit board 40, which will be described later, so that the transmitted red light is emitted toward the front side. It has become.

The front portion 71 of the housing cover 70 has a central portion that is opened with approximately the same size as the top plate 73a of the convex portion 73, and the dark box 30 is arranged in a loosely inserted state.
Further, at one end of the front portion 71, there is provided a button input portion 71a that is formed of a separate member and is supported so as to be pushed backward. The button input unit 71a is in contact with a test push button (not shown) mounted on the circuit board 40 located on the back side thereof, and the test input button 71a is pushed backward to thereby push the test push button. Input operation is possible. The test push button is for performing a test for confirming the operation of the piezoelectric diaphragm 11, and when an input operation is performed, the circuit of the circuit board 40 sounds so as to sound the piezoelectric diaphragm 11 regardless of smoke detection. It is configured.
Reference numeral 71c is an input string connected to the back side of the button input unit 71a. By pulling the input string 71c, the test push button can be pressed via the button input unit 71a. Yes.

  In addition, an alarm output unit 71b composed of a plurality of slits penetrating the front part 71 on the front and back sides is provided at a position on the front part 71 opposite to the button input part 71a across the convex part 73. Yes. The piezoelectric diaphragm 11 is disposed in the vicinity of the alarm output unit 71b in the housing 50, and emits an alarm sound to the outside of the housing 50 through the alarm output unit 71b when activated.

The rear surface side of the cylindrical portion 72 of the housing cover 70 is wide open, and a partition plate 75 set to an outer diameter that can be inserted into the cylindrical portion 72 is inserted and closed. That is, as shown in FIGS. 3 and 4, the housing cover 70 and the partition plate 75 form a storage space for the piezoelectric diaphragm 11, the dark box 30, and the circuit board 40. Note that the partition plate 75 is also integrally formed of a white resin material, like the case cover 70.
During storage, the dark box 30 is connected to the circuit board 40 by two claws 30a, the dark box 30 is disposed on the housing cover 70 side, and the circuit board 40 is disposed on the partition plate 75 side.
The partition plate 75 is formed with a pair of protrusions 76 and 76 for positioning the circuit board 40 on the surface facing the circuit board 40, and the positioning holes 42 formed through the circuit board 40. The circuit board 40 is properly positioned by being inserted into 42 and held so that the circuit board 40 is not rattled.
That is, when the partition plate 75 is inserted from the rear side end of the cylindrical portion 72 of the housing cover 70 while positioning the circuit board 40 integrally connected to the dark box 30 by the protrusions 76 and 76, the dark box 30 and the circuit board are arranged. 40 is stably held by being sandwiched between the casing cover 70 and the partition plate 75 in the front-rear direction, and is stably held by the protrusions 76 in the planar direction of the circuit board 40.
The piezoelectric diaphragm 11 and its mounting structure 90 are provided on the front side of the partition plate 75, and details thereof will be described later.
The housing cover 70 and the partition plate 75 are fixedly connected by a set screw (not shown).

The base body 60 is a disk having the same diameter as the outer diameter of the housing cover 70, and is connected so as to be concentric with the housing cover 70 via a partition plate 75. The base body 60 is also formed by integral molding with a white resin material.
As shown in FIG. 2, a long hole-like or keyhole-like screw insertion hole 61 for screwing the wall surface of the fire alarm 10 is provided through the back side of the base body 60. ing. The base body 60 is integrally provided with a wall hanging ring 62 for suspending the fire alarm 10 on a hook or the like provided on the wall surface. This wall-hanging ring 62 is cut off when the fire alarm 10 is suspended from a wall and installed, and its base end is attached to the attachment hole 65 for use.

In addition, a pair of connecting hooks formed in an L shape with their tips facing inward are formed at positions corresponding to both ends of a predetermined diameter on the back side of the partition plate 75, and correspondingly. Thus, a pair of connecting hooks that are formed in an L shape with their ends facing outward are formed at positions that are both ends of a predetermined diameter on the front side of the base body 60. Then, the base body 60 and the partition plate 75 are connected by rotating the base body 60 with respect to the partition plate 75 so that the respective distal end portions of the respective connecting hooks are inserted inside the counterpart. It is like that.
The area between the base body 60 and the partition plate 75 is used as a storage space for a battery (not shown).

(Smoke detection means)
The smoke sensing means 45 includes a light emitting element 46 (for example, a light emitting diode) and a light receiving element 47 (for example, a photodiode) provided in the dark box 30. That is, the light emitting element 46 is arranged in the dark box 30 with its irradiation range limited, and the light receiving element 47 is arranged in the dark box 30 with the light receiving range limited so that the inspection light is not directly incident ( (See FIG. 6).
Furthermore, in the dark box 30, the light emitting element 46 and the light receiving element 47 are arranged so that the irradiation range and the light receiving range partially overlap, and smoke is generated in the overlapping region (referred to as smoke detection region A). When entering, the light emitted from the light emitting element 46 is scattered by the smoke and enters the light receiving element 47 so that the smoke is detected.

(Circuit board)
The circuit board 40 is connected to the light emitting element 46 and the light receiving element 47 of the smoke sensing means 45 and the piezoelectric diaphragm 11 (not shown) that emits an alarm sound, and further shows the operating state of the sensing means 20 on the board. The LED 41 as a light source and the test push button described above are mounted.
The LED 41 is mounted on a surface of the circuit board 40 on which the dark box 30 is attached and hidden behind the dark box 30.

Then, as the first function of the circuit board 40, the light emitting element 46 is turned on, and when the light receiving element 47 detects with a light intensity equal to or higher than a predetermined value at the time of lighting, the circuit board 40 performs a process of ringing the piezoelectric diaphragm 11. The circuit to be configured is configured.
As a second function, a circuit is configured to execute a process for ringing the piezoelectric diaphragm 11 regardless of whether or not the light receiving element 47 is detected when the test push button is pressed.
Further, as a third function, the circuit board 40 is in a state where the power is normally turned on so that the light emitting element 46 and the light receiving element 47 of the smoke detecting means 45 can detect smoke (in operation). At some point, a circuit for executing a process of turning on the LED 41 is configured.

(Light guide member)
The light guide member 12 includes a first light guide portion 12a formed in a round bar shape and a second light guide portion 12b formed in a flat plate shape, and these are transparent materials having high light transmittance (for example, Resin).
The first light guide 12a having a round bar shape penetrates through the dark box 30 and the lower end thereof faces the LED 41 provided on the substrate 40, and the red light of the LED 41 is disposed on the dark box 30. It transmits to the 2nd light guide part 12b.
And the 2nd light guide part 12b is extended to the action | operation display part 73d of the front center of the housing | casing cover 70 mentioned above, The red light transmitted from the 1st light guide part 12a is transmitted from the said action | operation display part opening part 73d. The light is emitted toward the outside.

(Dark box)
FIG. 5 is a perspective view of the dark box 30, and FIG. 6 is a cross-sectional view showing the internal structure of the dark box 30.
The dark box 30 includes a front plate 31 or a rear plate 32 between the front plate 31 and the rear plate 32, and a circular front plate 31 on the front side, a circular rear plate 32 on the rear side, and the front plate 31 and the rear plate 32. These are composed of various structures, which will be described later, integrally formed in any one of the above and an insect screen (not shown) that covers the outer periphery of the dark box 30.
Note that the front plate 31 and the back plate 32 and the various structures integrally formed thereon are formed from a black resin having a high light absorption property.

The front plate 31 and the back plate 32 are both discs having the same outer diameter, and are connected to each other so as to be concentric.
Further, between the front plate 31 and the back plate 32, as shown in FIG. 6, a light emitting element holding portion 33 for holding the smoke sensing means 45 while covering the periphery except for the front of the light emitting element 46, and a smoke The light receiving element holding part 34 that holds the surroundings except for the front of the light receiving element 47 of the sensing means 45, the labyrinth part 35 that prevents intrusion of external light near the outer periphery of the dark box 30, and the light emitted from the light emitting element 46 Is prevented from directly entering the light receiving area of the light receiving element 47, and the light irradiated from the light emitting element 46 is received and condensed outside the smoke detection area A set by the light emitting element 46 and the light receiving element 47. The reflecting plate 37 is provided.

The light emitting element holding unit 33 includes a diaphragm unit 33b that holds the light emitting element 46 toward the center and restricts the irradiation range.
The light receiving element holding part 34 includes a diaphragm part 34b that holds the light receiving element 47 in the central direction and regulates the light receiving range.
The shielding plate 36 is disposed between the light emitting element holding part 33 and the light receiving element holding part 34 and restricts the irradiation range of the light emitting element 46 so as to be away from the light receiving element 47 side.
The overlapping range of the irradiation area defined by the light emitting element holding part 33 and the shielding plate 36 and the light receiving area defined by the light receiving element holding part 34 is a smoke detection area A, and smoke enters the smoke detection area A. As a result, scattered light is detected by the light receiving element 47.

The reflection plate 37 has a concave surface that reflects the light emitted from the light emitting element 46, condenses the light emitted from the light emitting element 46 to the outside of the dark box 30, and suppresses the influence of disturbance light other than scattered light during smoke detection. In addition, the S / N ratio can be improved.
The labyrinth part 35 is a wall surface of various shapes arranged so as to surround the smoke detection area A, and is arranged so as to mesh with each other while forming a gap through which smoke passes, so that the exterior to the smoke detection area A is provided. Prevents intrusion of light.
In addition, the code | symbol 38a is a hole part which penetrates the 1st light guide part 12a of the light guide member 12 formed penetrating the dark box.

(Piezoelectric diaphragm and its mounting structure)
7 is an exploded perspective view of the mounting structure 90 of the piezoelectric diaphragm 11 provided on the partition plate 75, and FIG. 8 is a front view of the partition plate 75.
First, the piezoelectric diaphragm 11 is mainly composed of a metal disk 11a and a piezoelectric element 11b having a smaller diameter (see FIG. 10). The piezoelectric element 11b is provided concentrically on one side of the metal disk 11a. It has been. And it can vibrate by supplying with electricity to the piezoelectric element 11b from the circuit board 40 mentioned above, and can generate a vibration sound.

  The attachment structure 90 of the piezoelectric diaphragm 11 is connected to the partition plate 75 of the housing 50 and includes the cover body 20 that holds the piezoelectric diaphragm 11 between the partition board 75, the partition plate 75, and the cover body 20. And a connecting structure 91 for connecting each other.

9A is a perspective view illustrating the front side of the cover body 20, FIG. 9B is a perspective view illustrating the back side, and FIG. 10 is a cross-sectional view taken along line YY in FIG.
The cover body 20 as a whole is composed of a plurality of plate-like parts integrally formed of resin. That is, the cover body 20 includes a small diameter cylindrical portion 21 that forms a cavity that resonates with the piezoelectric vibration plate 11, a circular flat plate portion 22 that faces the piezoelectric vibration plate 11 at one end of the small diameter cylindrical portion 21, and the piezoelectric vibration plate 11. A large-diameter cylindrical portion 23 that surrounds each other, an annular flat plate portion 24 that connects the cylindrical portions 21 and 23, a pair of leg portions 25 and 25 that extend toward the partition plate 75, and each leg portion 25 and 25. And engaging portions 26 and 26 that engage with the partition plate 75, and each of these portions is formed in a flat or curved plate shape.

The small-diameter cylindrical portion 21 is closed at its front end by a circular flat plate portion 22, and a sound emitting hole 22 a for emitting sound when the piezoelectric vibration plate 11 vibrates is formed in the circular flat plate portion.
Further, the end on the back side of the small diameter cylindrical portion 21 is wide open, and the outer diameter of the small diameter cylindrical portion 21 is set to be substantially uniform in the central axis direction and smaller than the outer diameter of the piezoelectric diaphragm 11. Yes.
In the state where the cover body 20 is attached to the partition plate 75, the piezoelectric diaphragm 11 is disposed so as to close the opening end portion of the small diameter cylindrical portion 21. In this state, the piezoelectric diaphragm 11 faces the inner surface of the circular flat plate portion 22 through the small diameter cylindrical portion 21, and a cylindrical hollow portion is formed by the piezoelectric vibrating plate 11, the small diameter cylindrical portion 21, and the circular flat plate portion 22. Is done.
The inner diameter and total length of the small diameter cylindrical portion 21, the inner diameter of the sound emitting hole 22 a of the circular flat plate portion 22, and the wall thicknesses of the small diameter cylindrical portion 21 and the circular flat plate portion 22 are determined when the piezoelectric diaphragm 11 vibrates (when sound is generated). It is set so as to cause resonance, and when the piezoelectric diaphragm 11 is energized, a sound with a larger sound pressure is emitted from the sound emission hole 22a.

The large-diameter cylindrical portion 23 has an end on the front side connected to an opening end of the small-diameter flat plate portion 21 via an annular flat plate portion 24, and a wide end on the back side.
The large-diameter cylindrical portion 23 has an inner diameter set slightly larger than the outer diameter of the piezoelectric diaphragm 11 and can store the piezoelectric diaphragm 11 inside.
Further, as shown in FIG. 11, the opposed end portion of the small diameter cylindrical portion 21 protrudes somewhat toward the back side from the annular flat plate portion 24, and the piezoelectric end portion is in contact with the protruding open end portion. The diaphragm 11 is stored and held in the large diameter cylindrical portion 23.
Further, two cutout portions 23a and 23b are formed on the peripheral surface of the large diameter cylindrical portion 23 (FIG. 9). The cover body 20 is attached and detached by sliding the partition plate 75 in the rotational direction. That is, during the detachable slide operation, the end portions of the cutout portions 23a and 23b come into contact with the projections 77 and 78 serving as stoppers protruding from the front side of the partition plate 75, so that the rotation operation is performed. This is for limiting to an appropriate range (FIG. 7).

Legs 25, 25 are formed at both ends in the diameter direction at the opening end of the large-diameter cylindrical portion 23, respectively. These leg portions 25, 25 are integrally formed on the same peripheral surface as the peripheral surface of the large diameter cylindrical portion 23, and from the end surface of the open end portion of the large diameter cylindrical portion 23 toward the cylindrical center line. It is formed in a protruding state (along the cylinder center line direction).
Further, plate-like engaging portions 26 and 26 are formed at the tip portions of the leg portions 25 and 25 so as to be substantially perpendicular to the plate surfaces of the leg portions 25 and 25. Each of the engaging portions 26 is extended outward in the radial direction of the large-diameter cylindrical portion 23.
These leg parts 25 and 25 and the engaging parts 26 and 26 comprise a part of the connection structure part 91 mentioned later.

Further, the cover body 20 has any plate-like portion adjacent to each other, that is, the boundary between the small-diameter cylindrical portion 21 and the annular flat plate portion 24, the boundary between the annular flat plate portion 24 and the large-diameter cylindrical portion 23, and the leg portion 25. Reinforcing ribs 27, 28, and 29 are provided integrally with the plate-like portions at the boundaries between the engaging portions 26, respectively.
Each reinforcing rib 27, 28, 29 is a plate-like body oriented in a direction substantially perpendicular to the plate surface of the flat plate portion located on each side of each. The reinforcing ribs 27, 28, and 29 are formed integrally at the boundary between the flat plate portion and the angle between the flat plate portion and the flat plate portion even when an external force is applied to the cover body 20. Is kept constant, the bending and distortion of the cover body 20 are suppressed, and the original shape can be maintained.
The reinforcing ribs 27 provided at the boundary between the small-diameter cylindrical portion 21 and the annular flat plate portion 24 are provided as a pair at both ends in the diameter direction of the small-diameter cylindrical portion and are formed so as to project in a square shape toward the outside in the diameter direction. Has been. As described above, since the cover body 20 is slid in the rotation direction when the cover body 20 is attached / detached, the pair of reinforcing ribs 27 also function as a knob in the rotation / slide operation, and the operability at the time of mounting work is achieved. Can be improved.
The plate surface shape, arrangement, and number of individual reinforcing ribs 27, 28, and 29 are not particularly limited. Except when the reinforcing rib 27 has a function other than reinforcement, It is desirable to have a necessary and sufficient number of individuals with an arrangement that is effective for suppressing bending and distortion of the flat plate portion.
Further, the reinforcing rib 28 is more preferably disposed at a height that does not hinder the vibration when the piezoelectric diaphragm 11 vibrates.

11 is a cross-sectional view taken along the line ZZ in FIG. 10, and FIG. 12 is an enlarged perspective view of the connecting structure 91. As shown in FIGS. 8 and 10 to 12, the connecting structure portion 91 engages with the leg portion 25 and the engaging portion 26 of the cover body 20 described above and the engaging portion 26 provided on the partition plate 75. An engaged portion 92 and a stopper 93 for maintaining the engaged state of the engaged portion 26 and the engaged portion 92 are provided.
The engaged portion 92 and the stopper 93 correspond to the leg portion 25 and the engaging portion 26 of the cover body 20 on the flat surface on the front side of the partition plate 75, and the diameter of the large-diameter cylindrical portion 23 described above. Are provided at a distance of approximately equal to each other. Further, the engaged portion 92 and the stopper 93 are integrally formed of the same material as the partition plate 75.

Each of the engaged portions 92 is formed in a plate shape so as to cover a part of the long hole portion 94 penetrating the partition plate 75 from the front side to the back side from the front side.
More specifically, each elongated hole portion 94 is formed in an arc shape on the same circumference having a diameter substantially equal to that of the large-diameter cylindrical portion 23, and each leg portion 25 and the engaging portion 26 of the cover body 20 are in front. It is inserted into each slot 94 from the side. Further, a step portion 95 on which the engaging portion 26 is placed is formed inside each elongated hole portion 94. The step portion 95 prevents the leg portion 25 and the engagement portion 26 of the cover body 20 from penetrating too deeply into the elongated hole portion 94.
The cover body 20 is attached to the partition plate 75 by a sliding operation in a direction rotating along the circumferential direction of the large-diameter cylindrical portion. And each engaging part 26 will move in the long hole part 94 in the case of the said slide operation. The long hole portion 94 is set to a length that exceeds at least twice the width of the engaging portion 26 in the slide operation direction.

As shown in FIGS. 8 and 12, the engaged portion 92 has only a partial range of the elongated hole portion 94, that is, a half on the downstream side in the slide operation direction in the longitudinal direction of the elongated hole portion 94 (strictly speaking, half Furthermore, a half range (substantially a quarter range) that is radially outward of the arc-shaped elongated hole portion 94 is covered from the front side.
When the cover body 20 is attached to the partition plate 75, the engaging portion 26 is inserted into the elongated hole portion 94 from the upstream side in the slide operation direction that is not covered by the engaged portion 92, and the cover body 20 is moved in a predetermined direction. The plate-like engaging portion 26 is inserted into the back side of the engaged portion 92 by rotating the engaging portion 92 to the back side.
At this time, as shown in FIG. 11, the front surface of the engaging portion 26 and the back surface of the engaged portion 92 are opposed to each other, and the engaged portion 92 partitions the cover body 20 with respect to the engaging portion 26. It will be in the state located in the direction (front side) spaced apart from the board 75. FIG. Therefore, the cover body 20 can be mounted on the partition plate 75 by the engagement between the engaging portion 26 and the engaged portion 92. That is, the engaging portion 2 and the engaged portion 92 are in a positional relationship that “the sliding operation of the cover body 20 prevents the wall surface of the partition plate 75 of the housing 50 and the cover body 20 from moving in a direction away from each other. It will function as an “opposing part”.

In addition, inclined surfaces 26a and 92a are formed on the front surface of the engaging portion 26 and on the upstream end in the sliding operation direction, and on the back surface of the engaged portion 92 and on the downstream end in the sliding operation direction, respectively. Yes.
The inclined surface 26a of the engaging portion 26 is inclined so as to guide the engaged portion 92 in a positional relationship that prevents movement of the engaged portion 92 in a direction in which the housing and the cover body are separated from each other during movement by a slide operation. ing. That is, the inclined surface 26 a is inclined in a direction in which the engaged portion 92 is guided to the front side of the engaging portion 26 by the sliding movement of the engaging portion 26. Further, the inclined surface 92 a is inclined in a direction in which the engaging portion 26 is guided to the back side of the engaged portion 92 by the sliding movement of the engaging portion 26.

The stopper 93 extends in a cantilevered state from the upstream end in the sliding operation direction of the long hole portion 94 toward the downstream side in the long hole portion 94. That is, the stopper 93 can bend the end portion on the downstream side in the slide operation direction by elastic deformation, and has a protruding portion protruding to the front side at the tip portion.
When the engaging portion 26 is moved from the upstream side to the downstream side in the elongated hole portion 94 by the slide operation, the engaging portion 26 is moved to the engaged portion 92 unless the front end portion of the stopper 93 is pushed down to the back side. A stopper 93 is provided so that it cannot be moved to the back side. Then, when the engaging portion 26 is moved to the back side of the engaged portion 92, the engaging portion 26 completely passes through the stopper 93, and the stopper 93 returns to the original position. The distal end abuts on the upstream end of the engaging portion 26 in the slide movement direction and restricts the reverse movement upstream.

Further, at the holding position of the piezoelectric diaphragm 11 in front of the partition plate 75, four contact projections 96 that contact the back side of the piezoelectric diaphragm 11 are integrally formed on the partition plate 75 (FIGS. 7 and 7). 10).
Each of the contact protrusions 96 is in the state where the piezoelectric diaphragm 11 is attached to the partition plate 75 by the mounting structure 90, and the piezoelectric vibration plate 11 is connected to each contact protrusion 96 and the rear side end of the small diameter cylindrical portion 21 of the cover body 20. Thus, the height (protrusion amount) can be pressed and clamped.
That is, the rear side end portion of the small-diameter cylindrical portion 21 and each contact protrusion 96 function as a contact portion that press-contacts the piezoelectric diaphragm 11 in a connected state of the partition plate 75 of the housing 50 and the cover body 20.

(Explanation of fire alarm operation)
First, an operation for attaching the piezoelectric diaphragm 11 to the partition plate 75 will be described. With the piezoelectric diaphragm 11 stored in the large-diameter cylindrical portion 23 of the cover body, each engaging portion 26 of the cover body 20 is inserted into the long hole portion 94 of the partition plate 75.
Then, by sliding the cover body 20 in a predetermined rotational direction (clockwise in FIG. 8) in such a state, the engaging part 26 enters the back side of the engaged part 92 and does not move in the reverse direction by the stopper 93. Locked to.
Further, in the course of the slide operation, the inclined portions 26a and 92a of the engaging portion 26 and the engaged portion 92 are guided so that the engaging portion 26 moves in the direction of sinking to the back side. The engaging portion and the engaged portion are in pressure contact with each other, and the piezoelectric diaphragm 11 is pressed from both the front side and the back side by the rear side end portion of the small-diameter cylindrical portion 21 and the respective contact projections 96 to be held. Holding is performed.
When the cover body 20 is turned, if the turning operation is performed by pinching the reinforcing ribs 27, 27 with fingers, the attachment is very easy.

Further, the operation of the assembled fire alarm 10 will be described. The fire alarm 10 is attached with the rear surface of the casing 50 in close contact with the ceiling surface of the building, or in close contact with a vertical wall surface.
When a battery as a power source is connected to the circuit board 40, the circuit board 40 performs predetermined initialization, and then the light emitting element 46 of the smoke sensing means 45 is turned on, and the LED 41 indicating the normal operation of the smoke sensing means 45 is also turned on. .
Further, when smoke due to fire is generated, the smoke enters the smoke detection area A through the opening 73 c of the housing 50 through the labyrinth part 35 of the dark box 30. Then, the irradiation light of the light emitting element 46 is scattered and received by the light receiving element 47, and the circuit board 40 sounds the piezoelectric diaphragm 11 from the light sensing of the light receiving element 47. Thereby, fire detection is performed.

(Effect of embodiment)
In the fire alarm 10, as the attachment structure 90 of the piezoelectric diaphragm 11, the engaging portion 26 is formed on the cover body 20 and the engaged portion 92 is formed on the partition plate 75, which partition the cover body 20 by a sliding operation. Since it is mounted and held on the plate 75, the piezoelectric diaphragm 11 can be held without using a fixing tool such as a screw, and the number of components can be reduced. Further, since the cover body 20 has both a function of forming a cavity for causing resonance and a function of holding the piezoelectric diaphragm 11, the number of parts can be further reduced as compared with the case where these are implemented by separate members. Is possible.

Further, since the piezoelectric diaphragm 11 can be easily attached by rotating and sliding the cover body 20, the work can be simplified and speeded up.
Particularly, since both the engaging portion 26 and the engaged portion 92 have the inclined surfaces 26a and 92a, the transition to the mounting state of the cover body 20 by the sliding operation is performed smoothly, and the piezoelectric diaphragm 11 can be further simplified and smoothed.

  Furthermore, since the partition plate 75 is provided with the stopper 93, the movement of the engagement portion 26 of the cover body 20 in the direction in which the engagement state is released from the engaged portion 92 is restricted. It is possible to maintain the mounting state of the cover body 20, maintain the holding state of the piezoelectric diaphragm 11, and suppress accidental disconnection.

  Further, since the small-diameter cylindrical portion 21 that presses the piezoelectric diaphragm 11 from both directions and the contact protrusion 96 are provided in a state where the cover body 20 is attached to the partition plate 75, the piezoelectric diaphragm 11 can be held in a sandwiched state. The piezoelectric diaphragm 11 can be stably held.

  Further, since the cover body 20 is provided with reinforcing ribs 27, 28, and 29 at each part, each plane on which the ribs are interposed even when the cover body is attached to the housing or when external force is applied after the attachment. Are maintained by the reinforcing ribs 27, 28, and 29, and the occurrence of bending and distortion of the cover body 20 is suppressed. Accordingly, the fluctuation or abnormality of the contact state between the small diameter cylindrical portion 21 and the piezoelectric diaphragm 11 when the cover body 20 is mounted is suppressed, and an appropriate contact state between the small diameter cylindrical portion 21 and the piezoelectric diaphragm 11 is maintained. Sound generation due to resonance of the diaphragm 11 can be performed satisfactorily and appropriately.

(Other)
In the present embodiment, the case where the piezoelectric diaphragm 11 is attached to the fire alarm device 10 is illustrated, but the object to which the piezoelectric diaphragm 11 is attached is not limited to this, and a piezoelectric diaphragm is required. The mounting structure shown in this embodiment can be applied to any electronic device.
Further, the stopper provided on the partition plate 75 side may be provided on the cover body 20 or only on the cover body 20.

It is a perspective view which shows the front side of the fire alarm which is embodiment of invention. It is a perspective view which shows the back side of a fire alarm. It is a disassembled perspective view of a fire alarm. It is sectional drawing of the fire alarm along the XX line shown in FIG. It is a perspective view of a dark box. It is sectional drawing which shows the internal structure of a dark box. It is a disassembled perspective view of the attachment structure of the piezoelectric diaphragm provided in the partition plate. It is a front view of a partition plate. FIG. 9A is a perspective view illustrating the front side of the cover body, and FIG. 9B is a perspective view illustrating the back side of the cover body. It is sectional drawing along the YY line in FIG. It is sectional drawing along the ZZ line in FIG. It is an expansion perspective view of a connection structure part.

Explanation of symbols

10 Fire alarm (electronic equipment)
11 Piezoelectric diaphragm 11a Metal disc (flat plate)
11b Piezoelectric element 20 Cover body 21 Small diameter cylindrical part (cavity part)
22 circular flat plate portion 22a sound emitting hole 23 large diameter cylindrical portion 24 annular flat plate portion 25 leg portion 26 engaging portion (opposing portion)
26a Inclined surfaces 27, 28, 29 Reinforcing rib 50 Housing 90 Mounting structure 92 Engagement part (opposing part)
91 Connecting structure portion 92a Inclined surface 93 Stopper 96 Contact protrusion (contact portion)

Claims (8)

A piezoelectric diaphragm mounting structure for holding a piezoelectric diaphragm having a piezoelectric element formed on one side of a flat plate between a housing of an electronic device and a cover body having a cavity that resonates with the piezoelectric diaphragm. And
As a connecting structure for connecting the housing and the cover body to each other,
Each of the casing and the cover body is provided with a facing portion having a positional relationship that prevents movement of the casing and the cover body in a direction away from each other by a sliding operation of the cover body. Vibration mounting structure.   2. The piezoelectric diaphragm mounting structure according to claim 1, wherein at least one of the facing portions of the housing or the cover body has an inclined surface inclined with respect to a sliding operation direction of the cover body.   2. The connecting structure portion is characterized in that a stopper is provided on at least one of the housing or the cover body to prevent a return movement of the facing portion of the cover body or the housing moved by the sliding operation. Or the attachment structure of the piezoelectric diaphragm of 2 description.   The contact part which press-contacts with respect to the said piezoelectric diaphragm in the connection state of the said housing | casing and a cover body was provided in both the said housing | casing and the cover body. The mounting structure of the piezoelectric diaphragm as described. A piezoelectric diaphragm mounting structure for holding a piezoelectric diaphragm having a piezoelectric element formed on one side of a flat plate between a housing of an electronic device and a cover body having a cavity that resonates with the piezoelectric diaphragm. And
A connection structure for connecting the housing and the cover body to each other;
The cover body is composed of a plurality of plate-like portions formed integrally, and a reinforcing rib formed integrally with each plate-like portion is provided at the boundary between any plate-like portions adjacent to each other. A piezoelectric diaphragm mounting structure. The cover body includes, as the plate-like portion, a leg portion extending to the housing side, and an engagement portion that is bent at the tip of the leg portion and engages the housing.
6. The piezoelectric diaphragm mounting structure according to claim 5, wherein the reinforcing rib is provided between the leg portion and the engaging portion. The cover body includes a small-diameter cylindrical portion that forms the hollow portion, a circular flat plate portion that faces the piezoelectric diaphragm at one end of the small-diameter cylindrical section and has a sound emitting hole, and a large-diameter surrounding the piezoelectric diaphragm. A diameter cylindrical portion and an annular flat plate portion connecting the cylindrical portions are integrally formed,
2. A reinforcing rib formed integrally with the small-diameter cylindrical portion and the annular flat plate portion is provided outside the cover body and at a boundary between the small-diameter cylindrical portion and the annular flat plate portion. The mounting structure of the piezoelectric diaphragm as described in any one of 1 to 6.   A reinforcing rib formed integrally with the large-diameter cylindrical portion and the annular flat plate portion is provided inside the cover body and at the boundary between the large-diameter cylindrical portion and the annular flat plate portion. Item 8. A piezoelectric diaphragm mounting structure according to Item 7.

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