thermal sensor

Abstract

Make the heat detector thinner. [Solution] The heat detector 1 has a cylindrical shape with a substantially closed bottom and lid, and comprises a housing 21 and a cover 22, a circuit board 30 housed in the housing, and heat sensing units 315A and 315B attached to the circuit board 30. The circuit board 30 has a first insertion hole through which the heat sensing units 315A and 315B are inserted at an angle. The heat sensing units 315A and 315B each have a rod-shaped lead portion, a heat-sensitive portion connected to one end of the lead portion, and a pin connected to the other end of the lead portion. The first insertion hole has an opening and a first notch formed on the edge of the opening. The circuit board 30 further has a first land arranged on the first surface so as to surround the first notch. The pins of the heat sensing units 315A and 315B are inserted through the first notch and their tips are soldered to the first land.

Description

Technical Field

[0001] The present invention relates to a thermal sensor.

Background Art

[0002] Conventionally, a thermal sensor includes a heat detection unit such as a thermistor, and detects the occurrence of a fire by detecting the heat of a hot air flow generated by the fire. For example, Patent Document 1 describes a thermal sensor provided with a heat detection unit provided so as to protrude outside a housing in order to facilitate the heat detection of a hot air flow.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the thermal sensor described in Patent Document 1, it is necessary to provide a protector in order to protect the heat-sensitive part of the heat detection unit. Therefore, there is a problem that the thickness of the thermal sensor becomes thick.

[0005] The present invention has been made in view of such circumstances, and an object thereof is to reduce the thickness of the thermal sensor.

Means for Solving the Problems

[0006] To solve the above problems, the heat detector according to the present invention comprises a housing, a circuit board housed in the housing, and a heat detection unit attached to the circuit board, wherein the circuit board has a first insertion hole through which the heat detection unit is inserted at an angle, the heat detection unit has a rod-shaped lead portion, a heat-sensitive portion connected to one end of the lead portion, and a pin connected to the other end of the lead portion, the first insertion hole has an opening and a first notch formed on the edge of the opening, the circuit board further has a first land arranged on a first surface so as to surround the first notch, and the pin of the heat detection unit is inserted through the first notch and its tip is soldered to the first land.

[0007] The circuit board may further include a second land positioned on a second surface, which is the surface opposite to the first surface, so as to surround the first notch, and through holes connecting the first land and the second land.

[0008] The first land is not connected to any circuit mounted on the first surface, while the second land may be connected to any circuit mounted on the second surface.

[0009] The first through hole further has a second notch formed adjacent to the first notch at the edge of the opening, and the circuit board further comprises a third land disposed on the first surface so as to surround the second notch, the first land having a first portion and a second portion facing each other on either side of the first notch, the second portion being closer to the third land than the first portion and narrower than the first portion, the third land having a third portion and a fourth portion facing each other on either side of the second notch, the third portion being closer to the first land than the fourth portion and narrower than the fourth portion.

[0010] The heat detector further comprises an intermediate plate housed in the housing and positioned below the circuit board, the intermediate plate having a second insertion hole through which the heat sensing part is inserted at an angle, the housing having a cover positioned below the intermediate plate, the intermediate plate and the cover forming a flow space through which air flows substantially parallel to the intermediate plate, and the portion of the intermediate plate facing the heat sensing part in a bottom view may be formed flat. [Effects of the Invention]

[0011] According to the present invention, heat detectors can be made thinner. [Brief explanation of the drawing]

[0012] [Figure 1] Bottom view of heat detector 1 [Figure 2] Side view of heat detector 1 [Figure 3] Plan view of heat detector 1 [Figure 4] Exploded perspective view of heat detector 1 with base 10 removed. [Figure 5] Bottom view of main body 21 [Figure 6] Plan view of main body 21 [Figure 7] Bottom view of circuit board 30 [Figure 8] Plan view of circuit board 30 [Figure 9] Bottom perspective view of circuit board 30 [Figure 10] Diagram showing the external appearance of the heat sensing unit 315. [Figure 11] Enlarged view of the vicinity of the insertion hole 314 shown in Figure 7. [Figure 12] Enlarged view of the vicinity of the insertion hole 314 shown in Figure 8. [Figure 13] Cross-sectional view of line BB in Figure 12 [Figure 14] Enlarged view of the vicinity of the insertion hole 314 shown in Figure 8, with the heat sensing unit 315 removed. [Figure 15] Cross-sectional view of line CC in Figure 14 [Figure 16] Bottom view of the middle plate 50 [Figure 17]Cross-sectional view taken along line A-A of FIG. 1, showing only the middle plate 50, cover 22, and heat detection unit 315 in particular [Figure 18] Bottom view of the heat sensor 1 with the cover 22 removed [Figure 19] Bottom perspective view of the heat sensor 1 with the cover 22 removed [Figure 20] Perspective view of the attachment method of the heat detection unit 315 [Figure 21] Perspective view of the attachment method of the heat detection unit 315 [Figure 22] Perspective view of the attachment method of the heat detection unit 315 [Figure 23] Cross-sectional view taken along line D-D of FIG. 22

Mode for Carrying Out the Invention

[0013] 1. Embodiment A wireless heat sensor 1 according to an embodiment of the present invention will be described with reference to the drawings 1-1. Configuration FIG. 1 is a bottom view of the heat sensor 1. FIG. 2 is a side view of the heat sensor 1. FIG. 3 is a plan view of the heat sensor 1. FIG. 4 is an exploded perspective view of the heat sensor 1 with the base 10 removed

[0014] The heat sensor 1 includes a base 10 and a housing 20. The housing 20 houses a circuit board 30, a speaker 40, and a middle plate 50

[0015] The base 10 has a covered cylindrical shape and is fixed to the ceiling by screws or the like

[0016] The housing 20 has a substantially bottomed and covered cylindrical shape and includes a main body 21 and a cover 22

[0017] FIG. 5 is a bottom view of the main body 21. FIG. 6 is a plan view of the main body 21 The main body 21 is circular and includes a bottom surface 211, a top surface 212, a battery housing 213, a speaker housing 214, a circuit board housing 215, push-in sections 216A and 216B, antenna holding sections 217A and 217B, and push-in section holding sections 218A and 218B.

[0018] The bottom surface 211 is the surface facing the circuit board 30.

[0019] The upper surface 212 is the surface facing the base 10. The base 10 is fixed at its open end to the periphery of the main body 21 on the side of the upper surface 212.

[0020] The battery housing 213 is a battery housing that accommodates a cylindrical battery. The housed battery is connected to the circuit board 30 and supplies power to each circuit. The battery housing 213 is convex on the bottom surface 211 side of the main body 21 and concave on the top surface 212 side, with the battery housed in the concave part on the top surface 212 side. When viewed from the bottom, the battery housing 213 extends radially from the center of the main body 21 to its periphery.

[0021] The speaker housing 214 is a wall portion that protrudes substantially vertically from the bottom surface 211 of the main body 21, and is used to position the speaker 40. When viewed from the bottom, the speaker housing 214 has a substantially C-shape and is formed adjacent to the battery housing 213.

[0022] The circuit board housing section 215 is a wall portion that protrudes substantially vertically from the bottom surface 211 of the main body 21, and is used to position the circuit board 30. When viewed from the bottom, the circuit board housing section 215 is formed to surround a substantially L-shaped area.

[0023] The push-in parts 216A and 216B are rod-shaped members formed to be pressable into the bottom surface 211 of the main body 21. The push-in parts 216A and 216B are formed in the main body 21 by forming a U-shaped through groove when viewed from the bottom. When viewed from the bottom, the push-in parts 216A and 216B are formed on the opposite side of the speaker housing 214, with the battery housing 213 in between. Of the push-in parts 216A and 216B, push-in part 216A is positioned to be in contact with the registration switch 308, which will be described later, and when push-in part 216A is pressed by the user, the registration switch 308 is pressed. On the other hand, push-in part 216B is positioned to be in contact with the erase switch 309, which will be described later, and when push-in part 216B is pressed by the user, the erase switch 309 is pressed.

[0024] The antenna holding parts 217A and 217B are rectangular plates that protrude substantially vertically from the periphery of the bottom surface 211 of the main body 21, and are used to position the antenna 310, which will be described later. Of the antenna holding parts 217A and 217B, antenna holding part 217A is inserted through an insertion hole 507 (see Figure 16) formed in the middle plate 50, and positions the antenna 310 on the bottom surface 501 of the middle plate 50. On the other hand, antenna holding part 217B is inserted through a notch 508 (see Figure 16) formed in the middle plate 50, and positions the antenna 310 on the bottom surface 501 of the middle plate 50. The antenna holding parts 217A and 217B are provided with U-shaped grooves at their tips, and the antenna 310 is held in place within these grooves.

[0025] The push-in part holding parts 218A and 218B are rectangular plates that protrude substantially vertically from the periphery of the bottom surface 211 of the main body 21, and position the push-in part 60 (see Figures 1 and 4), which will be described later. The push-in part holding parts 218A and 218B are equipped with U-shaped grooves at their tips, and these grooves position the shaft portion 61 of the push-in part 60. Of the push-in part holding parts 218A and 218B, the push-in part holding part 218A is further equipped with a U-shaped groove at its tip, and the antenna 310 is held within this groove.

[0026] Next, as shown in Figures 1 and 2, the cover 22 has a bottomed cylindrical shape, and its open end is fixed to the periphery of the main body 21 on the bottom surface 211 side. This cover 22 comprises a cylindrical portion 221 and a bottom portion 222.

[0027] The cylindrical portion 221 is provided with 14 ventilation holes 2211 arranged in the circumferential direction. Each ventilation hole 2211 is formed on the bottom 222 side of the cylindrical portion 221 and extends elongated in the circumferential direction of the cylindrical portion 221. Each ventilation hole 2211 allows a horizontal airflow to flow into the circulation space formed between the cover 22 and the intermediate plate 50. This horizontal airflow is an airflow that flows approximately parallel to the ceiling surface. The horizontal airflow that flows into the circulation space flows approximately parallel to the intermediate plate 50.

[0028] The bottom portion 222 is provided with a push-in portion 60. The push-in portion 60 is a plate body having an oval shape when viewed from the bottom, and has a shaft portion 61 at one end (radially outward from the cover 22). The push-in portion 60 is mounted so as to be able to be pushed into a through hole formed in the bottom portion 222. The push-in portion 60 is positioned so as to be able to press the inspection switch 307, which will be described later, and when the push-in portion 60 is pressed by the user, the inspection switch 307 is pressed.

[0029] On the upper surface of the bottom portion 222, a pair of cover-side retaining portions (not shown) are provided, each having a U-shaped groove (not shown) at its tip. The shaft portion 61 of the push-in portion 60 is sandwiched between these pair of cover-side retaining portions and the push-in portion retaining portions 218A and 218B of the main body 21, thereby positioning the push-in portion 60 within the through-hole of the cover 22.

[0030] The bottom portion 222 further includes two vertical holes 2221 formed on its periphery, facing each other. Each vertical hole 2221 is a substantially oval-shaped through-hole, allowing a vertical airflow to flow into the aforementioned circulation space. This vertical airflow is an airflow that flows in a direction substantially perpendicular to the ceiling surface. The above is a description of the main unit 21 and the cover 22.

[0031] Next, we will describe the circuit board 30 located beneath the main unit 21. Figure 7 is a bottom view of the circuit board 30. Figure 8 is a top view of the circuit board 30. Figure 9 is a bottom perspective view of the circuit board 30. The circuit board 30 is formed by cutting out a fan-shaped portion of a substantially circular board, and has a substantially L-shape. The circuit board 30 includes a bottom surface 301, a top surface 302, a notch 303, a base 304, a first extension 305, a second extension 306, an inspection switch 307, a registration switch 308, an erase switch 309, an antenna 310, a conductor 311, a control circuit 312 (not shown), a wireless communication circuit 313 (not shown), through holes 314A and 314B, and heat detection units 315A and 315B.

[0032] The bottom surface 301 is the surface facing the middle plate 50.

[0033] The upper surface 302 is the surface facing the main body 21.

[0034] The notch 303 is a fan-shaped notch with a central angle of approximately a right angle. The notch 303 is the area in which the battery housing 213 of the main body 21 and the speaker 40 are located.

[0035] The base portion 304 is a roughly rectangular section.

[0036] The first extension 305 is a portion extending from one end of the base 304. The first extension 305 comprises an inner edge 3051 and an outer edge 3052. The inner edge 3051 is a straight edge facing the notch 303. The outer edge 3052 is the edge other than the inner edge 3051. Outer edge Part 3052 is an arc-shaped edge that includes a straight portion in part.

[0037] The second extension 306 is a portion extending from the other end of the base 304. The second extension 306 forms a substantially right angle with the first extension 305, with the notch 303 in between. The second extension 306 comprises an inner edge 3061 and an outer edge 3062. The inner edge 3061 is a substantially straight edge facing the notch 303. The outer edge 3062 is the edge other than the inner edge 3061. The outer edge 3062 is an arc-shaped edge that includes a partially straight portion.

[0038] A speaker 40 is connected to the tip end of the inner edge 3061 of the second extension 306. The speaker 40 has a disc shape.

[0039] The base portion 304, the first extension portion 305, and the second extension portion 306 are integrally provided.

[0040] When the inspection switch 307 is pressed, tests are performed on the internal circuitry (fire detection unit, etc.) and the battery life, and the results are indicated by an LED (not shown). The inspection switch 307 is located on the bottom surface 301 of the circuit board 30, near the rear end of the second extension 306.

[0041] The registration switch 308 is a switch used to set the wireless channel used by the heat detector 1. The registration switch 308 is installed on the upper surface 302 of the circuit board 30. The registration switch 308 is installed on the rear end side of the first extension 305.

[0042] The erase switch 309 is used to erase the wireless channel settings in the heat detector 1. The erase switch 309 is installed on the upper surface 302 of the circuit board 30. The erase switch 309 is installed on the rear end side of the first extension 305.

[0043] The antenna 310 is a metal wire. One end of the antenna 310 is connected to the wireless communication circuit 313, and it extends along the inner wall of the cover 22, from the outer edge 3052 of the first extension 305 to the outer edge 3062 of the second extension 306 when viewed from the bottom.

[0044] The antenna 310 comprises a straight portion 3101 and an arc portion 3102. One end of the straight portion 3101 is connected to the wireless communication circuit 313, extends substantially vertically from the bottom surface 301 of the circuit board 30, and is inserted into an antenna hole 509 (see Figure 16) formed in the middle plate 50. One end of the arc portion 3102 is connected to the other end of the straight portion 3101, and, in a bottom view, extends along the inner wall of the cover 22 from the outer edge 3052 of the first extension portion 305 to the outer edge 3062 of the second extension portion 306.

[0045] The antenna 310 is connected to one end of the circuit board 30, which has a roughly L-shape when viewed from below, and extends so as not to enclose the notch 303.

[0046] The conductor 311 is a metal wire. One end of the conductor 311 is connected to ground (not shown) on the circuit board 30, and in a bottom view, it extends from the inner edge 3061 of the second extension 306 through the notch 303 to the outer edge 3062 of the second extension 306 along the inner wall of the cover 22.

[0047] The conductor 311 comprises a straight portion 3111 and an arc portion 3112. One end of the straight portion 3111 is connected to ground (not shown) on the circuit board 30, and in a bottom view, it extends from the inner edge 3061 of the second extension 306 through the notch 303. One end of the arc portion 3112 is connected to the other end of the straight portion 3111, and in a bottom view, it extends along the inner wall of the cover 22 to the outer edge 3062 of the second extension 306.

[0048] The conductor 311 is connected to the other end of the circuit board 30, which has a roughly L-shape when viewed from below, and the main body 2 It does not surround the battery housing 213 (in other words, the battery) of part 1, but extends to surround the speaker 40.

[0049] By increasing the length of the ground using this conductor 311, the gain of the antenna 310 is improved compared to when this conductor 311 is not provided. Furthermore, since this conductor 311 is wired so as not to surround the battery when viewed from below, the gain of the antenna 310 is further improved in this respect as well.

[0050] The control circuit 312 includes a CPU, ROM, RAM, etc. The CPU executes the control program stored in the ROM to perform the fire detection process, fire signal transmission process, and wireless channel setting process, which will be described later.

[0051] The wireless communication circuit 313 transmits and receives wireless signals to and from other heat detectors 1 and relay devices via the antenna 310.

[0052] The through holes 314A and 314B are each substantially rectangular through holes, and the heat sensing unit 315A is inserted diagonally through the through hole 314A, and the heat sensing unit 315B is inserted diagonally through the through hole 314B. The through hole 314A is formed in the base portion 304, and the through hole 314B is formed in the second extension portion 306. In the following description, unless otherwise necessary, the through holes 314A and 314B will be collectively referred to as "through hole 314," and the heat sensing units 315A and 315B will be collectively referred to as "heat sensing unit 315."

[0053] Figure 10 shows the external appearance of the heat sensing unit 315. The heat sensing unit 315 comprises a rod-shaped lead portion 3151 made of lead wires, a substantially spherical heat-sensing portion 3152 connected to one end of the lead portion 3151, a substantially rectangular parallelepiped-shaped base portion 3153 connected to the other end of the lead portion 3151, and two pins 3154 extending from the base portion 3153. The heat-sensing portion 3152 of this heat sensing unit 315 is a temperature detection element such as a thermistor.

[0054] Figures 11 to 15 are enlarged views of the vicinity of the insertion hole 314 described above. Figure 11 is an enlarged view of the vicinity of the insertion hole 314 shown in Figure 7. Figure 12 is an enlarged view of the vicinity of the insertion hole 314 shown in Figure 8. Figure 13 is a cross-sectional view taken along line BB of Figure 12. Figure 14 is an enlarged view of the vicinity of the insertion hole 314 shown in Figure 8 with the heat sensing unit 315 removed. Figure 15 is a cross-sectional view taken along line CC of Figure 14. The insertion hole 314 has an opening 3141 and notches 3142A and 3142B.

[0055] The opening 3141 is a rectangular through-hole, sized to allow the heat sensing unit 315 to pass through. The base 3153 and pin 3154 of the heat sensing unit 315 are inserted through the opening 3141.

[0056] The notches 3142A and 3142B are U-shaped notches formed side by side on the edge of the opening 3141. The notches 3142A and 3142B are formed to extend substantially parallel to the width direction of the opening 3141. A pin 3154 is inserted through the notches 3142A and 3142B. With these openings 3141 and the through holes 3142A and 3142B, the heat sensing unit 315 can be mounted at an angle, even if it is not at the edge of the circuit board 30 (for example, near the center).

[0057] Here, the inclination angle θ of the heat sensing unit 315 with respect to the circuit board 30 (see Figure 13) is determined by considering the balance between the heat receiving characteristics required of the heat sensing unit 3152 and the thickness of the heat detector 1. The heat receiving characteristics of the heat sensing unit 3152 increase as the inclination angle θ increases (in other words, the heat sensing unit 315 The performance improves as the distance between 2 and the circuit board 30 increases. On the other hand, the thickness of the heat detector 1 decreases as the inclination angle θ decreases (in other words, as the distance between the heat sensing part 3152 and the circuit board 30 decreases). The inclination angle θ is set, for example, in the range of 5 to 60 degrees, taking these factors into consideration. In this context, the heat reception characteristic refers to the difference between the temperature detected by the heat-sensing element 3152 and the actual ambient temperature; the better the heat reception characteristic, the smaller the temperature difference.

[0058] As shown in Figure 12, a land 316 is arranged on the upper surface 302 of the circuit board 30 so as to surround the notch 3142A. The land 316 is a roughly U-shaped soldering area, and the pin 3154 of the heat sensing unit 315 is soldered to this land 316. As shown in Figure 14, this land 316 has a third portion 3161 and a fourth portion 3162 that face each other on either side of the notch 3142A. The width W1 of the third portion 3161, which is closer to the adjacent land 317, is narrower than the width W2 of the fourth portion 3162. This is to prevent the formation of solder bridges between lands 316 and 317.

[0059] A thermal relief 318 is formed around the land 316, partially enclosing it. Here, as shown in Figure 15, the thermal relief 318 is a narrow groove that separates the land 316 from the surrounding resist layer 327. Furthermore, this land 316 is not connected to any circuit on the upper surface 302 of the circuit board 30. Therefore, when soldering, the heat applied to this land 316 does not dissipate easily, making the soldering process easier.

[0060] On the other hand, around the notch 3142B, a land 317 is arranged on the upper surface 302 of the circuit board 30 so as to surround the notch 3142B. The land 317 is a roughly U-shaped soldering area, and the pin 3154 of the heat sensing unit 315 is soldered to this land 317. As shown in Figure 14, this land 317 has a first portion 3171 and a second portion 3172 that face each other on either side of the notch 3142B. The width W4 of the second portion 3172, which is closer to the adjacent land 316, is narrower than the width W3 of the first portion. This is to prevent the formation of solder bridges between lands 316 and 317.

[0061] A thermal relief 319 is formed around the land 317, partially enclosing it. Here, as shown in Figure 15, the thermal relief 319 is a narrow groove for separating the land 317 from the surrounding resist layer 327. Furthermore, this land 317 is not connected to any circuit on the upper surface 302 of the circuit board 30. Therefore, when soldering, the heat applied to this land 317 does not dissipate easily, making the soldering process easier.

[0062] Next, on the bottom surface 301 of the circuit board 30, a roughly U-shaped land 320 is arranged around the notch 3142B, as shown in Figure 11. A thermal relief 321 is formed around a portion of this land 320. Here, the thermal relief 321 is a narrow groove for separating the land 320 from the resist layer 328 around it, as shown in Figure 15. In the portion of the land 320 not surrounded by the thermal relief 321, it is connected to one of the circuits on the bottom surface 301 of the circuit board 30 via a conductive wiring 322.

[0063] As shown in Figure 15, this land 320 is electrically connected to the land 317 on the upper surface 302 side of the circuit board 30 via three through-holes 323. Here, the through-holes 323 are through-holes formed in the circuit board 30, and are through-holes that allow electrical contact between the land 320 and the land 317. Therefore, the heat sensing unit 3 soldered to the land 317 The output signal 15 is transmitted to the land 320 via the through-hole 323, and the output signal transmitted to the land 320 is transmitted to the circuit on the bottom surface 301 of the circuit board 30 via the wiring 322.

[0064] Furthermore, the through-hole 323 connects land 320 and land 317, making it difficult for both lands to peel off from the circuit board 30. In particular, when an external force is applied to the tip of the heat sensing unit 315, it is expected that a force will be applied in a direction that would cause land 317 to peel off from the circuit board 30, but even in such a case, peeling from the circuit board 30 will be suppressed. When the pin 3154 of the heat sensing unit 315 is soldered to the land 317, solder fills the through-hole 323, which further firmly fixes the land 317 and land 320 to the circuit board 30. As a result, peeling of these lands from the circuit board 30 is suppressed.

[0065] On the other hand, around the notch 3142A, a roughly U-shaped land 324 is arranged on the bottom surface 301 of the circuit board 30 so as to surround the notch 3142A. A thermal relief 325 is formed around a part of this land 324. Here, the thermal relief 325 is a narrow groove for separating the land 324 from the resist layer 328 surrounding it.

[0066] As shown in Figure 15, the land 324 is electrically connected to the land 316 on the upper surface 302 side of the circuit board 30 via three through-holes 326. Here, the through-holes 326 are through-holes formed in the circuit board 30, and are through-holes that allow the land 324 and land 316 to be electrically connected. The connection between the land 324 and land 316 via these through-holes 326 makes it difficult for both lands to peel off from the circuit board 30. In particular, when an external force is applied to the tip of the heat sensing unit 315, it is expected that a force will be applied in a direction that will cause the land 316 to peel off from the circuit board 30, but even in such a case, peeling from the circuit board 30 is suppressed. When the pin 3154 of the heat sensing unit 315 is soldered to the land 316, solder fills the through-hole 326, which further firmly fixes the land 316 and land 324 to the circuit board 30. As a result, peeling of these lands from the circuit board 30 is suppressed. The above is a description of the circuit board 30.

[0067] Next, we will describe the intermediate plate 50 located beneath the circuit board 30. Figure 16 is a bottom view of the middle plate 50. Figure 17 is a cross-sectional view along line AA of Figure 1, specifically showing only the middle plate 50, cover 22, and heat sensing unit 315. The middle plate 50 is formed by cutting out a portion of a roughly circular plate body and has a roughly U-shape. The middle plate 50 includes a bottom surface 501, a top surface 502 (see Figure 4), a cutout portion 503, a base portion 504, a first extension portion 505, a second extension portion 506, an insertion hole 507, a cutout portion 508, an antenna hole 509, a speaker hole 510, a switch hole 511, and insertion holes 512 and 513.

[0068] The bottom surface 501 is the surface facing the cover 22, which is positioned below the middle plate 50. The bottom surface 501 is formed in a flat shape, creating a space for airflow between it and the cover 22 (see Figure 17). This bottom surface 501 is located on approximately the same plane as the upper edge 22111 of the ventilation holes 2211 of the cover 22, making it easier for the horizontal airflow flowing in from the ventilation holes 2211 to flow smoothly parallel to the middle plate 50.

[0069] The upper surface 502 is the surface facing the circuit board 30.

[0070] The notch 503 is roughly L-shaped, and the battery housing 213 of the main body 21 is located there. It is a domain.

[0071] The base portion 504 is a roughly semicircular section.

[0072] The first extension 505 and the second extension 506 are portions that extend from the base 504. The first extension 505 and the second extension 506 extend approximately parallel to each other, with the notch 503 in between.

[0073] The base portion 504, the first extension portion 505, and the second extension portion 506 are integrally provided.

[0074] The through-hole 507 is a through-hole for inserting the antenna holding portion 217A of the main body 21. The antenna holding portion 217A, inserted through the through-hole 507, positions the antenna 310 on the bottom surface 501 of the middle plate 50.

[0075] The notch 508 is a through-hole for inserting the antenna holding portion 217B of the main body 21. The antenna holding portion 217B, inserted through the notch 508, positions the antenna 310 on the bottom surface 501 of the middle plate 50.

[0076] The intermediate plate 50 is positioned relative to the main body 21 by inserting the antenna holding part 217A through the insertion hole 507 and the antenna holding part 217B through the notch 508.

[0077] The antenna hole 509 is a through-hole for inserting the antenna 310. The antenna hole 509 is formed on the periphery of the second extension 506.

[0078] Figure 18 is a bottom view of the heat detector 1 with the cover 22 removed. Figure 19 is a bottom perspective view of the heat detector 1 with the cover 22 removed. The antenna 310, inserted through the antenna hole 509, is routed along the bottom surface 501 of the middle plate 50. The antenna 310 is positioned by the antenna holding parts 217A and 217B and the push-in part holding part 218A of the main body 21.

[0079] Next, the speaker hole 510 is formed in the center of the first extension 505. The speaker hole 510 is formed to face the speaker 40.

[0080] The switch hole 511 is a through-hole for inserting the inspection switch 307. The switch hole 511 is formed in the center of the base 504.

[0081] The insertion hole 512 is a through-hole through which the heat sensing unit 315A is inserted at an angle. This insertion hole 512 is formed on one end of the base 504 and has an opening 5121 and a notch 5122. The opening 5121 is a rectangular through-hole and is sized to allow the heat sensing unit 315 to pass through. The base 3153 and lead portion 3151 of the heat sensing unit 315 are inserted through the opening 5121. On the other hand, the notch 5122 is an I-shaped notch and is formed to extend substantially parallel to the length direction of the opening 5121. The lead portion 3151 is inserted through this notch 5122.

[0082] The heat-sensing portion 3152 of the heat-sensing unit 315A, which is inserted through the insertion hole 512, faces a flat portion R1 on the bottom surface 501 when viewed from the bottom (see Figures 17 and 18). In addition, as described above, the bottom surface 501 is formed to be flat and is located on approximately the same plane as the upper edge portion 22111 of the ventilation hole 2211 of the cover 22. Therefore, the horizontal airflow flowing in from the ventilation hole 2211 flows smoothly through the circulation space, resulting in better heat reception characteristics for the heat-sensing unit 315A compared to cases where such a structure is not adopted.

[0083] The insertion hole 513 is a through hole through which the heat sensing unit 315B is inserted at an angle. This insertion hole 513 is formed on the other end side of the base 504 and has an opening 5131 and a notch 5132. The opening 5131 is a rectangular through hole and is sized to allow the heat sensing unit 315 to pass through. The base 3153 and lead portion 3151 of the heat sensing unit 315 are inserted through the opening 5131. On the other hand, the notch 5132 is an I-shaped notch and is formed to extend substantially parallel to the length direction of the opening 5131. The lead portion 3151 is inserted through this notch 5132.

[0084] The heat-sensing portion 3152 of the heat-sensing unit 315B, which is inserted through the through hole 513, faces a flat portion R2 on the bottom surface 501 when viewed from the bottom (see Figures 17 and 18). In addition, as described above, the bottom surface 501 is formed to be flat and is located on approximately the same plane as the upper edge portion 22111 of the ventilation hole 2211 of the cover 22. Therefore, the horizontal airflow flowing in from the ventilation hole 2211 flows smoothly through the circulation space, resulting in better heat reception characteristics for the heat-sensing unit 315B compared to cases where such a structure is not adopted. The above is an explanation of the middle plate 50.

[0085] Here, the method for attaching the heat sensing unit 315 to the circuit board 30 and the intermediate plate 50 will be explained with reference to the figures. Figures 20 to 23 are explanatory diagrams of this attachment method. Figures 20 to 22 are perspective views of the attachment method, and Figure 23 is a cross-sectional view of Figure 22 along line DD. Note that in Figure 23, hatching has been omitted for clarity. When attaching the heat sensing unit 315 to the circuit board 30 and the intermediate plate 50, a jig 2 is used. The jig 2 is a roughly disc-shaped device and includes a protrusion 201 for positioning the intermediate plate 50 and a recess 202 for positioning the heat sensing unit 315.

[0086] As shown in Figure 20, the intermediate plate 50 is placed on top of the jig 2, and the circuit board 30 is placed on top of the intermediate plate 50. In this state, as shown in Figure 21, the heat sensing unit 315A is inserted through the insertion hole 314A of the circuit board 30 and the insertion hole 512 of the intermediate plate 50. As shown in Figures 22 and 23, the heat sensing unit 3152 of the inserted heat sensing unit 315A abuts against the bottom corner of the recess 202 of the jig 2. In addition, its pin 3154 is inserted through the notches 3142A and 3142B of the circuit board 30. As a result, the heat sensing unit 315A is positioned. In this state, the worker solders the pin 3154 of the heat sensing unit 315A to the lands 316 and 317 of the circuit board 30. At this time, since the heat sensing unit 315A is positioned, the worker can perform the soldering work with both hands, making the work easier.

[0087] Meanwhile, the heat sensing unit 315B is inserted through the insertion hole 314B of the circuit board 30 and the insertion hole 513 of the middle plate 50. The inserted heat sensing unit 315B is soldered to the lands 316 and 317 of the circuit board 30 in the same manner as the heat sensing unit 315A.

[0088] 1-2.Operation The operation of heat detector 1 will be explained. Specifically, the fire detection process, fire signal transmission process, and wireless channel setting process will be described.

[0089] 1-2-1. Fire Detection Procedure When a fire occurs within the monitoring area of ​​the heat detector 1, a vertical airflow is generated from the source of the fire towards the ceiling. Upon reaching the ceiling, the vertical airflow changes direction and becomes a horizontal airflow flowing parallel to the ceiling surface. Of the vertical and horizontal airflows, the vertical airflow flows into the circulation space through the vertical holes 2221 in the cover 22 of the heat detector 1. The horizontal airflow, on the other hand, flows into the circulation space through the ventilation holes 2211 in the cover 22. The airflow that flows into the circulation space transfers heat to the heat detection unit 315.

[0090] The control circuit 312 of the heat detector 1 periodically receives output values ​​from the heat detection unit 315 and determines whether the ambient temperature is above a predetermined temperature. If the control circuit 312 determines that the ambient temperature is above a predetermined temperature as a result of the vertical or horizontal airflow entering the circulation space, it emits an alarm sound from the speaker 40 and transmits a fire signal from the wireless communication circuit 313 to other heat detectors 1 or relay devices.

[0091] 1-2-2. Fire Signal Transfer Processing When another heat detector 1 detects a fire and the fire signal transmitted from this heat detector 1 is received by the wireless communication circuit 313, the control circuit 312 emits an alarm sound from the speaker 40 and also causes the wireless communication circuit 313 to transmit fire signals to other heat detectors 1 or relay devices.

[0092] 1-2-3. Wireless channel setting process When the user presses down the push-in part 216A of the main unit 21 and the registration switch 308 is pressed and held down, the control circuit 312 switches to wireless channel setting mode. Subsequently, the control circuit 312 changes the wireless channel each time the registration switch is pressed briefly. Each time the wireless channel is changed, the control circuit 312 emits a guide voice from the speaker 40 notifying the wireless channel number. Then, when the registration switch 308 is pressed and held down again, the control circuit 312 memorizes the number of the selected wireless channel and exits wireless channel setting mode. The wireless channel numbers stored in this manner are erased when the user presses the push-in section 216B of the main unit 21 and the erase switch 309 is pressed and held down.

[0093] In the heat detector 1 described above, the heat detection unit 315 is mounted on the circuit board 30 at an angle. Therefore, compared to the case where the heat detection unit 315 is mounted vertically to the circuit board 30, the heat detector 1 can be made thinner.

[0094] 2. Variations The above embodiment may be modified as follows. The following modifications may be combined with each other.

[0095] 2-1. Variation 1 The shape of the housing 20 and the arrangement of its components are not limited to the illustrated example and may be modified as appropriate within the scope of the invention described in the claims.

[0096] 2-2. Variation 2 The shape of the circuit board 30 and the arrangement of its components are not limited to the illustrated example and may be modified as appropriate within the scope of the invention described in the claims.

[0097] For example, three or more through holes 314 may be formed. The shape and size of the opening 3141 of the through hole 314 may be appropriately changed according to the shape and size of the base 3153 of the heat sensing unit 315 inserted into the through hole 314. The number, shape, and size of the notches 3142A or 3142B of the through hole 314 may be appropriately changed according to the number, shape, and size of the pins 3154 of the heat sensing unit 315 inserted into the through hole 314. The number, shape, and size of the lands 316 or 317 may be appropriately changed according to the number, shape, and size of the pins 3154 of the heat sensing unit 315 inserted into the through hole 314. The number of through holes 323 and 326 may be five or fewer, or seven or more.

[0098] 2-3. Variation 3 The number of pins 3154 of the heat sensing unit 315 may be one or three or more. If the number of pins 3154 is set to one, the lead portion 3151 of the heat sensing unit 315 may be connected directly to pin 3154 without going through the base portion 3153.

[0099] 2-4. Variation 4 The shape of the intermediate plate 50 and the arrangement of its components are not limited to the illustrated example and may be modified as appropriate within the scope of the invention described in the claims.

[0100] 2-5. Variation 5 The invention described in the claims may also be applied to non-wireless heat detectors. [Explanation of Symbols]

[0101] 1…Heat detector, 2…Jig, 10…Base, 20…Housing, 21…Main body, 22…Cover, 30…Circuit board, 40…Speaker, 50…Middle plate, 60…Push-in part, 61…Shaft part, 201…Convex part, 202…Concave part, 211…Bottom surface, 212…Top surface, 213…Battery housing, 214…Speaker housing, 215…Circuit board housing, 216A, 216B…Push-in part, 217A, 217B…Antenna holder, 218A, 218B…Push-in part holder, 221…Cylindrical part, 222 ...bottom, 301...bottom surface, 302...top surface, 303...notch, 304...base, 305...first extension, 306...second extension, 307...inspection switch, 308...registration switch, 309...erase switch, 310...antenna, 311...conductor, 312...control circuit, 313...wireless communication circuit, 314A, 314B...insertion hole, 315A, 315B...heat detection unit, 316, 317, 320, 324...land, 318, 319, 321, 325...thermal relief, 322...Wiring, 323, 326...Through-hole, 327, 328...Resist layer, 501...Bottom surface, 502...Top surface, 503...Notch, 504...Base, 505...First extension, 506...Second extension, 507...Through hole, 508...Notch, 509...Antenna hole, 510...Speaker hole, 511...Switch hole, 512, 513...Through hole, 2211...Ventilation hole, 3051...Inner edge, 3052...Outer edge, 3061...Inner edge, 3062...Outer edge, 3101...Straight line Part, 3102...arc section, 3111...straight section, 3112...arc section, 3141...opening, 3142A, 3142B...notch, 3151...lead section, 3152...heat-sensitive section, 3153...base, 3154...pin, 3161...third section, 3162...fourth section, 3171...first section, 3172...second section, 5121...opening, 5122...notch, 5131...opening, 5132...notch, 22111...upper edge, R1, R2...part, W1~W4...width

Claims

1. The casing cover and Circuit board and A heat detection unit attached to the circuit board, A middle plate is placed between the cover and the circuit board. Equipped with, The heat sensing unit protrudes further toward the cover than the intermediate plate. The aforementioned intermediate plate and the aforementioned cover form a circulation space through which airflow flows. The cover has a bottom, Two through holes are formed on the periphery of the bottom portion, facing each other. Each of the two through holes allows an airflow to flow into the circulation space that is substantially perpendicular to the bottom. A heat detector characterized by the following features.

2. The intermediate plate has an opening through which the heat sensing unit is inserted. The heat detector according to feature 1.

3. The heat detection unit includes two heat detection units provided on the outer edge of the circuit board. The heat-sensing portions of the two heat-sensing units are each facing different through-holes among the two through-holes. The heat detector according to claim 1 or 2.

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