Information transmission device

Abstract

To provide an information transmission device for reducing a failure occurrence rate in a control section and a transmission section.SOLUTION: In a sensor node 10, a bottom plate 11a of a frame 11 is held between an internal space Sa where a control module 23 and a wireless module 24 are stored and a lower cover 15 which transmits heat input from the outer side to a heat receiving side substrate 31 of a Peltier unit 30. Then, the bottom plate 11a functions as a partition wall, so as to make it difficult to allow the heat input to the lower cover 15 to be transmitted to the internal space Sa. Consequently, in the sensor node 10, the control module 23 and the wireless module 24 are prevented from being exposed to high temperature even when attached to positions close to a high temperature heat generation source, since the heat input to the lower cover 15 is not easily transmitted to the internal space Sa. Thus, problems such as performance deterioration or failure occurrence due to exposure of electronic components of the control module 23 and the wireless module 24 to high temperature are suppressed, so that the failure occurrence rate can be reduced.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an information transmission device that transmits information input from the outside via a wireless communication line.

Background Art

[0002] As an information transmission device that transmits information input from the outside such as a sensor via a wireless communication line, for example, there is a "thermoelectric power generation transmitter" disclosed in Patent Document 1 below. This thermoelectric power generation transmitter includes a thermoelectric power generation module that generates power when heated from the outside, and is configured such that an arithmetic processing device, an amplifier circuit, etc. mounted on a circuit board can be driven by this electromotive force. Therefore, the thermoelectric power generation transmitter is often used by being attached to a position close to a high-temperature heat source, that is, an environment where the thermoelectric power generation module can sufficiently generate such driving power.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the thermoelectric power generation transmitter disclosed in Patent Document 1 above, a circuit board on which an arithmetic processing device, an amplifier circuit, etc. are mounted is housed in a space facing a heat receiving plate that receives heat from a high-temperature heat source. Therefore, the space in which the circuit board is housed tends to become high temperature as the temperature of the heat receiving plate rises, and the period is also very long. That is, during the period when the thermoelectric power generation transmitter is operating, there is a possibility that the electronic components of the circuit board such as the arithmetic processing device and the amplifier circuit are almost always exposed to high temperatures. Therefore, there is a risk of leading to deterioration of the performance of these electronic components and occurrence of failures (increase in failure rate).

[0005] Furthermore, in the thermoelectric power generation transmitter described in Patent Document 1, a resin outer frame is sandwiched between aluminum heat receiving plates and heat dissipation plates to form a space for housing the circuit board. Although Patent Document 1 does not mention the antenna from which the wireless module radiates radio waves, it is stated that the outer frame is made of a "material that has radio wave transparency" (Patent Document 1; paragraph number 0014), so it can be inferred that at least the antenna is housed in the same space as the circuit board, either by printing a pattern antenna on the circuit board or mounting a chip antenna on the circuit board.

[0006] Therefore, in the thermoelectric power generation transmitter described in Patent Document 1, the antenna housing space is sandwiched between aluminum heat receiving plates and heat sinks over a wide area. As a result, the radio waves radiated from the antenna within this space are radiated to the outside if they are directed towards the resin outer frame, while the rest are reflected between the heat sinks and heat receiving plates, or escape to the ground via the heat receiving plates if the heat receiving plates are connected to earth, making it difficult for them to be radiated to the outside. Consequently, in such a thermoelectric power generation transmitter configuration, the radiation pattern of the antenna may be disrupted or the radiation efficiency may decrease, which presents a problem in that the range of radio waves is difficult to extend.

[0007] The present invention was made to solve the above-mentioned problems and aims to provide an information transmission device that can reduce the failure rate of the control unit and the transmitting unit. Another object of the present invention is to provide an information transmission device that can extend the range of the transmitted wave. [Means for solving the problem]

[0008] To achieve the above objective, the technical means of claim 1 described in the claims is adopted. According to this means, the information transmission device comprises a thermoelectric conversion unit, a heat receiving unit, a heat dissipation unit, a cover unit, a control unit, and a transmission unit. The thermoelectric conversion unit, which generates electricity and outputs DC power when there is a temperature difference between the heat receiving side and the heat dissipation side, has its heat receiving side thermally coupled to one end of the heat receiving unit, and its heat dissipation side thermally coupled to the outside of the bottom of the heat dissipation unit. The control unit and the transmission unit are mounted inside the cover unit that closes the opening surrounded by the peripheral wall unit opposite the bottom of the heat dissipation unit, and these are housed in an internal space partitioned by the bottom and peripheral wall unit of the heat dissipation unit and the cover unit.

[0009] In other words, the bottom of the heat dissipation section is interposed between the internal space housing the control unit and the transmission unit, and the heat receiving unit that transmits heat input from the outside to the heat receiving side of the thermoelectric conversion unit. This bottom section functions as a partition, making it difficult for heat input from the outside to the heat receiving unit to be transferred to the internal space housing the control unit, etc. As a result, even if the information transmission device is installed in a position close to a high-temperature heat source, heat input from the outside to the heat receiving unit is difficult to transfer to the internal space housing the control unit and transmission unit, thus preventing the control unit and transmission unit from being exposed to high temperatures. Note that the bottom of the heat dissipation section and the peripheral wall of the heat dissipation section do not need to be connected and may be separated as long as they can be connected in a way that allows for thermal coupling.

[0010] Furthermore, the technical means of claim 2 described in the patent claims is adopted. According to this means, the entire lid is made of a material that can allow the transmitted waves output by the transmitter to pass through, or a part of it that covers the antenna of the transmitter (the part that covers the entire antenna when orthographically projected in a front view of the lid) is made of a material that can allow the transmitted waves output by the transmitter to pass through. As a result, even if the antenna of the transmitter is housed in the internal space, the transmitted waves output from it can pass through the lid and be radiated to the outside. Therefore, compared to the case where the lid is made of a metal material or the like that can reflect the transmitted waves without allowing them to pass through, disturbances in the antenna's radiation pattern and a decrease in radiation efficiency caused by the presence of the lid are less likely to occur.

[0011] Furthermore, the technical means of claim 3 described in the claims is adopted. According to this means, a plate-like space is provided between the outer surface of the bottom of the heat dissipation section and the side surface of one end of the heat receiving section, extending to the vicinity of the peripheral edges of both surfaces. As a result, between the internal space housing the control unit and the transmitting unit and the heat receiving section that transmits heat input from the outside to the heat receiving side of the thermoelectric conversion section, a plate-like space is interposed, in addition to the bottom of the heat dissipation section, which extends to the vicinity of the peripheral edges between the outer surface of the bottom of the heat dissipation section and the side surface of one end of the heat receiving section. Therefore, the air present in such a plate-like space increases the thermal conductivity resistance between the bottom and the heat receiving section, functioning as an insulating layer and making it even more difficult for heat input from the outside to the heat receiving section to be transmitted to the internal space housing the control unit, etc., thereby further preventing the control unit, etc. from being exposed to high temperatures. Furthermore, since this plate-like space extends to the vicinity of the peripheral edge between the outer surface of the bottom of the heat dissipation section and the side surface of one end of the heat receiving section, it becomes possible to accommodate a thermoelectric conversion unit that is plate-shaped within this range, such that the heat receiving side is thermally coupled to one end of the heat receiving section and the heat dissipation side is thermally coupled to the outside of the bottom of the heat dissipation section. In other words, by providing such a plate-like space, it becomes possible to accommodate a relatively large thermoelectric conversion unit. [Effects of the Invention]

[0012] In this invention, even if the information transmission device is mounted in a position close to a high-temperature heat source, heat input from the heat receiving section from the outside is less likely to be transferred to the internal space housing the control unit and the transmission unit, thus preventing the control unit and transmission unit from being exposed to high temperatures. Therefore, performance degradation and failures caused by exposure of the electronic components constituting the control unit and transmission unit to high temperatures are less likely to occur, thus reducing the failure rate of the control unit and transmission unit. Furthermore, even if the antenna of the transmission unit is housed in the internal space, the transmitted waves output from it can pass through the cover and be radiated to the outside. Therefore, compared to the case where the cover is made of a metal material that can reflect the transmitted waves without allowing them to pass through, disturbances in the antenna's radiation pattern and a decrease in radiation efficiency due to the presence of the cover are less likely to occur. Therefore, the range of the transmitted waves can be extended. [Brief explanation of the drawing]

[0013] [Figure 1] This is a system configuration diagram showing an example of a monitoring system configuration using a sensor node according to an embodiment of the present invention. [Figure 2] This figure shows an example of the configuration of the sensor node of this embodiment. Figure 2(A) is a front view. Figure 2(B) is a cross-sectional view seen from the direction of arrow 2B when cut along the dashed line shown in Figure 2(A). Figure 2(C) is a rear view showing the inside of the upper cover portion that constitutes the sensor node. [Figure 3] This figure shows an example of the configuration of the sensor node of this embodiment. Figure 3(A) is a front view of the sensor node with the upper and lower covers removed in half lengthwise. Figure 3(B) is a top or bottom view of the state shown in Figure 3(A). Figure 3(C) is a rear view of the state shown in Figure 3(A). [Figure 4] This is a block diagram showing an example of the electrical configuration of the sensor node in this embodiment. [Figure 5] This flowchart shows the flow of control processing performed by the control module that constitutes the sensor node of this embodiment. [Figure 6] This figure shows another example of the sensor node of this embodiment. Figure 6(A) is a front view. Figure 6(B) is a cross-sectional view seen from the direction of arrow 6B when the diagram in Figure 6(A) is cut along the dashed line. [Modes for carrying out the invention]

[0014] Hereinafter, an embodiment of the information transmission device of the present invention applied to a sensor node that detects and wirelessly transmits information of a monitored object (information of physical quantities such as temperature, humidity, atmospheric pressure, vibration frequency, rotational speed, speed, acceleration, current, and voltage) will be described with reference to the figures. First, an example of the configuration of a monitoring system using the sensor node 10 according to this embodiment (hereinafter referred to as "this monitoring system") will be described based on Figure 1. Figure 1 shows a system configuration diagram representing an example of the configuration of this monitoring system. This monitoring system is composed of, for example, a plurality of sensor nodes 10 that detect information of physical quantities, a wireless node 80 that receives the information of physical quantities detected from these sensor nodes 10 via a wireless communication line, and a computer 90 connected to this wireless node 80 that acquires the information of physical quantities received by the wireless node 80.

[0015] In this embodiment, the sensor node 10 is attached to, for example, a motor 101 for power, a pipe 102 through which high-temperature liquids or gases (high-temperature fluids) flow, or an industrial furnace 103 such as a heat treatment furnace, and transmits temperature information from these to the wireless node 80. The motor 101, pipe 102, and industrial furnace 103 are all high-temperature heat sources whose parts exposed to the outside, such as housings or casings, can generate high heat. Therefore, the sensor node 10 in this embodiment is attached to these heat sources, and as will be described later, a Peltier unit generates electricity, and the DC power output therefrom drives a control module and a wireless module to wirelessly transmit information of physical quantities input from the sensor. In this embodiment, the sensor is, for example, a temperature sensor, which detects the temperature of specific locations in the motor 101, pipe 102, or industrial furnace 103.

[0016] Next, an example configuration of the sensor node 10 of this embodiment will be described based on Figures 2 to 4. Figures 2 and 3 illustrate diagrams showing an example configuration of the sensor node 10. These diagrams will be explained later. Figure 4 shows a block diagram illustrating an example of the electrical configuration of the sensor node.

[0017] As shown in FIGS. 2 and 3, the sensor node 10 is composed of a frame portion 11, an upper cover portion 12, a window member 13, a spacer portion 14, a lower cover portion 15, a printed circuit board 21, a Peltier unit 30, etc. FIGS. 2(A) and 3(A) show the front view of the sensor node 10, FIG. 2(B) shows the cross-sectional view of the sensor node 10, FIG. 2(C) shows the back view of the upper cover portion 12 to which the printed circuit board 21 is attached, FIG. 3(B) shows the plan view or bottom view of the sensor node 10, and FIG. 3(C) shows the back view of the sensor node 10, respectively.

[0018] The frame portion 11 is a bottomed and lidless box made of metal such as aluminum having a horizontally long rectangular shape in a front view (see FIG. 3(A)), and the bottom plate portion 11a and the peripheral wall portion 11b are integrally formed so as to have the bottom plate portion 11a and the peripheral wall portion 11b connected thereto, and a portion surrounded by the peripheral wall portion 11b and facing the bottom plate portion 11a is open (see FIG. 2(B)). At the top of the peripheral wall portion 11b, a stepped portion 11c is formed in which the upper portion 11c' on the inner side in the circumferential direction is set higher than the lower portion 11c'' on the outer side in the circumferential direction (see FIGS. 3(A) and (B)).

[0019] Through holes 11d are formed near the four corners of the frame portion 11, respectively, enabling the insertion of bolts 16 described later. Round wiring holes 11e through which two wirings 41 of the Peltier unit 30 described later can be inserted are formed in the bottom plate portion 11a, and round wiring holes 11f through which the wiring 51 can be drawn out from the printed circuit board 21 housed in the internal space Sa of the frame portion 11 to the external space Sc are formed in the peripheral wall portion 11b as described later (see FIGS. 2(B), 3(A), and (C)).

[0020] The upper cover portion 12 is a lid having a horizontally long rectangular shape substantially the same as that of the frame portion 11 in a front view, and notch portions 12a for thinning the thickness are formed at the four corners thereof (see Fig. 2(A)). In the notch portions 12a, through holes 12c are formed at the same positions as the through holes 11d of the frame portion 11 in a state where the upper cover portion 12 closes the opening of the frame portion 11 (see Figs. 2(B) and (C)). In a state where the opening of the frame portion 11 is closed, a convex portion 12b is formed on the outer peripheral edge of the upper cover portion 12 at a height that can abut against the lower portion 11c” (step portion 11c) of the frame portion 11, and an annular groove 12d is formed on the inner side in the circumferential direction of the convex portion 12b.

[0021] In this annular groove 12d, in a state where the opening of the frame portion 11 is closed, an O-ring 19 that can be press-fitted to the upper portion 11c’ (step portion 11c) of the frame portion 11 to partition the internal space Sa and the external space Sc of the frame portion 11 in a liquid-tight manner is fitted. Thus, as will be described later, in a state where the frame portion 11 and the upper cover portion 12 are screwed and fastened to the spacer portion 14 by bolts 16 that are screwed into the spacer portion 14, it is possible to prevent foreign matters such as mist-like oil, water, dust, and dirt from entering the internal space Sa from the outside.

[0022] In the present embodiment, a rectangular hole 12e is formed in the upper cover portion 12, and a window member 13 is fitted or insert-molded in the rectangular hole 12e (see Figs. 2(A) to (C)). In Figs.   2 and 3, the portion of the window member 13 is colored gray for convenience of drawing representation. Four female screw holes 12f are formed in the upper cover portion 12, and a printed circuit board 21 is attached to the upper cover portion 12 by four bolts 17 that are screwed into these female screw holes 12f (see Fig. 2(C)). The printed circuit board 21 is fixed to the upper cover portion 12 in a state of floating from the back surface of the upper cover portion 12 by spacers 27 through which the bolts 17 are inserted (see Fig. 2(B)).

[0023] This rectangular hole 12e is positioned in a region that covers the antenna 26 provided on the printed circuit board 21 in a front view, as described later, and in a portion where no female screw hole 12f is provided. The window member 13 is made of a resin material with good heat resistance and electromagnetic wave transmission properties. In this embodiment, the upper cover portion 12 is made of resin in part (the window member 13) and the remainder is made of a metal such as aluminum. Alternatively, the entire upper cover portion 12 may be made of a resin material with good heat resistance and electromagnetic wave transmission properties.

[0024] The spacer portion 14 is a frame whose outer periphery is a horizontally elongated rectangle, similar in shape to the outer periphery of the frame portion 11, and is set to be slightly wider than the plate thickness of the peripheral wall portion 11b of the frame portion 11. For example, it is made of a resin material with good heat resistance (see Figure 3(C)). The height (thickness) of the spacer portion 14 is set to a dimension that allows for the formation of the plate-like space Sb, which will be described later. In this embodiment, stepped portions that facilitate the positioning of the spacer portion 14 are formed on the bottom plate portion 11a of the frame portion 11 and the inner flat portion 15a of the lower cover portion 15, and the height of the spacer portion 14 is set to be greater than the height (thickness) of the plate-like space Sb by the height (depth) of these stepped portions.

[0025] The spacer portion 14 has female screw holes 14a formed near its four corners, into which bolts 16 that pass through the through holes 11d in the frame portion 11 and 12c in the upper cover portion 12 can be screwed. In addition, four other female screw holes 14b are formed inside these female screw holes 14a for fastening the lower cover portion 15 with bolts 18. As a result, the frame portion 11 and the upper cover portion 12 are fixed by screw fastening the female screw holes 14a of the spacer portion 14 with four bolts 16, and the lower cover portion 15 is fixed by screw fastening the female screw holes 14b of the spacer portion 14 with four bolts 18, so that the spacer portion 14 is interposed between the frame portion 11 and the lower cover portion 15 so as to surround the plate-like space Sb described later. The spacer portion 14 has the function of preventing foreign matter (such as mist-like oil or water, dust or dirt) from entering the plate-shaped space Sb from the outside, and of providing heat insulation by hindering heat transfer between the frame portion 11 and the lower cover portion 15.

[0026] The lower cover portion 15 is a horizontally elongated rectangular plate that is approximately the same shape as the frame portion 11 when viewed from the rear (see Figure 3(C)), and is attached to the aforementioned spacer portion 14 so as to form a plate-like space Sb between the bottom plate portion 11a of the frame portion 11 and the inner flat portion 15a of the lower cover portion 15 (see Figures 2(B) and 3(C)). In this embodiment, the Peltier unit 30 is housed in this plate-like space Sb as will be described later.

[0027] The outer flat portion 15b, which is the opposite side of the inner flat portion 15a, is formed to be almost entirely flat, and heat is input to this outer flat portion 15b from the outside (motor 101, piping 102, industrial furnace 103, etc.). For this reason, a counterbore hole capable of accommodating the screw head of a bolt 18 that is screwed into the female screw hole 14b of the spacer portion 14 to fasten the lower cover portion 15 to the spacer portion 14 is formed in the opening of the through hole 15c through which the bolt 18 passes, so that the screw head of the bolt 18 does not protrude from the outer flat portion 15b.

[0028] The printed circuit board 21 is housed within the internal space Sa of the frame portion 11 described above, and the composite module 22, boost module 25, antenna 26, etc. are mounted on it. As shown in Figure 4, these constitute the circuit unit 20. That is, the circuit unit 20 consists of the printed circuit board 21, the composite module 22 having a control module 23 and a wireless module 24, the boost module 25, the antenna 26, etc.

[0029] The composite module 22 is a one-chip type electronic device having a control module 23 and a wireless module 24. In this embodiment, it is powered by receiving DC power generated by the Peltier unit 30 via a boost module 25. The control module 23 is a microcontroller unit consisting of, for example, an MPU, memory (RAM, EEPROM), input / output interface, A / D converter, Peltier driver circuit, etc., and is connected to the wireless module 24 and the sensor 50. When the control processing described later is executed, control is performed such as transmitting sensor information input from the sensor 50 via the wireless module 24.

[0030] The wireless module 24 is a wireless transceiver capable of performing data communication in a predetermined frequency band. In this embodiment, for example, it is configured to perform wireless data communication compatible with WPAN (Wireless Personal Area Network) using existing communication protocols such as ZigBee® in the 2.4GHz band compliant with IEEE802.15.4. An antenna 26, such as a pattern antenna printed on a printed circuit board 21, is connected to this wireless module 24, and a transmission wave is radiated from this antenna 26.

[0031] The boost module 25 is a voltage converter that converts the DC voltage output from the Peltier unit 30 into a voltage (drive voltage) suitable for driving the composite module 22. In this embodiment, an energy storage device (e.g., an electric double-layer capacitor or lithium-ion battery, etc.) is interposed between the Peltier unit 30 and the boost module 25. Therefore, even if the Peltier unit 30 cannot generate sufficient power, DC power can be supplied to the composite module 22 as long as the energy storage device has stored a charge above a predetermined value.

[0032] Antenna 26 is an antenna capable of radiating high-frequency power in a predetermined frequency band output by the wireless module 24 of the composite module 22 as a transmitted wave, or inputting an incoming received wave to the wireless module 24. In this embodiment, for example, a pattern antenna printed on the printed circuit board 21 (for example, a modified inverted F-type antenna having a meander line structure) or a chip antenna mounted on the printed circuit board 21 is used as antenna 26. Antenna 26 may also be a wire-type antenna provided outside the printed circuit board 21 in the internal space Sa.

[0033] The antenna 26 housed in the internal space Sa is covered above (towards the upper cover portion 12) by a resin window member 13 with good electromagnetic wave transmission characteristics, or by such a resin upper cover portion 12. Since the window member 13 is provided in an area that covers the entire antenna 26 when orthographically projected in a front view of the upper cover portion 12, if the antenna 26 housed in the internal space Sa has a radiation pattern directed toward the upper cover portion 12, the transmitted waves radiated from the antenna 26 in that direction can pass through such a resin window member 13 and be radiated into the external space Sc. Therefore, the range of the transmitted waves radiated from the antenna 26 with such a radiation pattern can be extended.

[0034] The Peltier unit 30 is a thin, square-shaped thermoelectric conversion device composed of numerous Peltier elements 33 (thermoelectric elements) and two ceramic substrates (a heat-receiving substrate 31 and a heat-dissipating substrate 32). It is sandwiched between the bottom plate portion 11a and the lower cover portion 15 of the frame portion 11 and housed in the plate-shaped space Sb. The heat-receiving substrate 31 is in contact with the inner flat portion 15a of the lower cover portion 15, so that heat input from the outside (motor 101, etc.) can be transferred to the heat-receiving side of the Peltier element 33 via the heat-receiving substrate 31. The heat-dissipating substrate 32 is in contact with the bottom plate portion 11a of the frame portion 11, so that heat released from the heat-dissipating side of the Peltier element 33 can be dissipated to the bottom plate portion 11a. Between the heat-receiving substrate 31 and the lower cover portion 15, and between the heat-dissipating substrate 32 and the bottom plate portion 11a, a heat-conducting material such as a paste-like silicone grease with high thermal conductivity is interposed so that almost the entire surface of these substrates 31 and 32 can be well thermally coupled.

[0035] The Peltier unit 30 generates DC power through the Seebeck effect when there is a temperature difference between the heat-receiving substrate 31 and the heat-dissipating substrate 32. For this reason, the Peltier unit 30 is connected to two wires 41, a positive wire 42 and a negative wire 43. These wires 41 are inserted through wiring holes 11e formed in the bottom plate portion 11a and connected to the boost module 25 and energy storage device (not shown) on the printed circuit board 21 in the internal space Sa. As a result, the DC power generated by the Peltier unit 30 is converted into the drive voltage of the composite module 22 and supplied to the composite module 22, as described above.

[0036] Sensor 50 is a detector that detects a physical quantity and outputs that information to a dual wiring 51, and is electrically connected to the printed circuit board 21 via the wiring 51. In this embodiment, for example, sensor 50 is a temperature sensor and is configured to output the detected temperature information to the printed circuit board 21 via the wiring 51. In this embodiment, the temperature sensor outputs analog temperature data as temperature information, and this temperature data is input to the A / D converter of the control module 23. Note that sensor 50 may be any sensor capable of detecting a physical quantity, such as a vibration sensor, acceleration sensor, voltage sensor, or current sensor.

[0037] In this monitoring system, the sensor node 10 configured in this way is attached to the heat-generating part of a heat source such as a motor 101, and the sensor 50 is attached to a predetermined location on the sensor node 10. Similarly, other sensor nodes 10 are attached to the respective heat-generating parts of the piping 102 and industrial furnace 103, and the sensors 50 are attached to the respective predetermined locations on the piping 102 and industrial furnace 103. The sensor node 10 is attached with a heat-conducting material such as a paste-like silicone grease with high thermal conductivity interposed between the heat-generating part and the outer flat part 15b, such as a motor 101, so that the lower cover portion 15 can be thermally coupled to the heat-generating part over almost the entire surface of its outer flat portion 15b.

[0038] If a gap occurs between the heat-generating part (such as the motor 101) and the outer flat portion 15b due to the shape of the heat-generating part, an adapter (not shown) made of a material with good thermal conductivity that can fill the gap between the two may be interposed to thermally couple the heat-generating part (such as the motor 101) and the outer flat portion 15b of the lower cover portion 15. In this case, the sensor node 10 and the adapter are attached with a thermal conductive material such as silicone grease interposed between the heat-generating part and the adapter, and between the outer flat portion 15b and the adapter.

[0039] In this way, the sensor nodes 10 attached to the motor 101, etc., transmit the temperature information detected by each sensor 50 to the wireless node 80 when the control module 23 performs the control processing described below. The control processing performed by the control module 23 will now be explained with reference to Figure 5. Figure 5 shows a flowchart illustrating the flow of the control processing.

[0040] This control process is performed when the boost module 25 supplies a drive voltage to the sensor node 10 and the MPU of the control module 23 starts up, and the MPU then executes the control program stored in the memory (EEPROM) of the control module 23.

[0041] As shown in Figure 5, in the control process, a predetermined initialization process is first performed in step S101. In this initialization process, for example, the work area and flags provided in the memory (RAM) of the control module 23 are cleared, and the operating parameters for the wireless module 24 are set to default values. In addition, a predetermined transmission buffer for setting the data to be transmitted by the wireless module 24 is cleared, and the ID (identification information) of the sensor node 10 is written to this transmission buffer.

[0042] In the next step, S103, sensor information acquisition processing is performed. In this embodiment, for example, the temperature information (sensor information) output by the sensor 50 is acquired and set as transmission data directly in a predetermined area of ​​the predetermined transmission buffer, or the acquired temperature information (sensor information) is converted into a predetermined data format and then set as transmission data in the predetermined area. The date and time (year, month, day, hour, minute, second) of the transmission are written to this transmission buffer as a timestamp in a predetermined format. Since the transmission is performed in the next sensor information transmission processing (S105), the transmission time is actually the time immediately before transmission.

[0043] In the following step S105, sensor information transmission processing is performed. In this process, a command is sent to the wireless module 24 to wirelessly transmit the contents of the transmission buffer (transmission data) set in the previous step S103. As a result, the wireless module 24, for example, encrypts the contents of the transmission buffer (transmission data), adds error correction information, etc., and then wirelessly transmits it in a communication format and communication procedure according to a predetermined communication protocol. In some cases, transmission may occur after receiving transmission permission information from the wireless node 80.

[0044] As a result, the transmitted wave from the wireless module 24 via the antenna 26 is radiated from the internal space Sa through the window member 13 of the frame section 11 to the external space Sc, where it reaches the wireless node 80 and is received as a received wave. The wireless node 80 demodulates or decodes the received signal to obtain received data, extracts temperature information (sensor information) and its timestamp from the received data, and transmits it to the computer 90.

[0045] Meanwhile, after completing the sensor information transmission process (S105) at the sensor node 10, the next step S107 performs a sleep transition process. The sleep transition process is a preparatory step for the control module 23 to transition to a sleep state for a predetermined sleep time. For example, it involves saving status flags and stack information necessary for control processing to a predetermined work area, and starting the sleep timer. In addition, the control module 23 transitions to a power-saving mode when in sleep mode, significantly reducing power consumption.

[0046] The sleep state continues until a predetermined sleep time (e.g., 30 seconds) has elapsed (S109; No). Once the predetermined sleep time has elapsed (S109; Yes), the process returns to the sensor information acquisition process in step S103 to acquire the temperature information (sensor information) output by the sensor 50. After that, each of the processes described above is performed sequentially. As a result, the temperature information acquired from the sensor 50 is wirelessly transmitted to the wireless node 80 at predetermined sleep time intervals (e.g., 30 seconds), making it possible for the computer 90 to acquire this temperature information at predetermined sleep time intervals.

[0047] The predetermined sleep time may be set differently for each sensor node 10. For example, the sensor node 10 attached to the motor 101 may have a sleep time of 10 seconds, the sensor node 10 attached to the piping 102 may have a sleep time of 120 seconds, and the sensor node 10 attached to the industrial furnace 103 may have a sleep time of 300 seconds. This reduces unnecessary wireless communication compared to the case where the sleep time for all sensor nodes 10 is set to 10 seconds, thereby reducing the overall communication traffic of the monitoring system. As a result, the information processing load on the wireless node 80 and the computer 90 can be reduced.

[0048] If the power supply from the boost module 25 is interrupted and power is lost while the control module 23 is performing the control processing described above, the MPU of the control module 23 will enter an abort state (processing interruption state) where it cannot operate. Therefore, when power is supplied to the control module 23 again from the boost module 25, the MPU of the control module 23 will return to the beginning and start information processing from the initialization process (S101) described above.

[0049] As described above, in the sensor node 10 of this embodiment, the bottom plate portion 11a of the frame portion 11 is interposed between the internal space Sa in which the control module 23 and wireless module 24 are housed and the lower cover portion 15 which transmits heat input from the outside to the heat receiving side substrate 31 of the Peltier unit 30. Therefore, this bottom plate portion 11a functions as a partition, making it difficult for heat input from the outside to the lower cover portion 15 to be transmitted to the internal space Sa in which the control module 23 and the wireless module 24 are housed. As a result, even if the sensor node 10 is installed in a position close to a high-temperature heat source, heat input from the outside to the lower cover portion 15 will not be easily transmitted to the internal space Sa in which the control module 23 and wireless module 24 are housed, thus preventing the control module 23 and wireless module 24 from being exposed to high temperatures. Consequently, performance degradation and failures caused by exposure of the electronic components constituting the control module 23 and wireless module 24 to high temperatures will be less likely to occur, thus reducing the failure rate of the control module 23 and wireless module 24.

[0050] Furthermore, in the sensor node 10 of this embodiment, the upper cover portion 12 is formed of a resin material with good heat resistance and electromagnetic wave transmission properties that allows the transmitted waves output by the wireless module 24 to pass through, specifically the portion that covers the antenna 26 of the wireless module 24 when orthographically projected in a front view, i.e., the window member 13. Alternatively, the entire upper cover portion 12 is formed of such a resin material with good heat resistance and electromagnetic wave transmission properties. As a result, even if the antenna 26 of the wireless module 24 is housed in the internal space Sa, the transmitted waves output from it can pass through the window member 13 or the upper cover portion 12 and be radiated into the external space Sc. Therefore, compared to the case where the upper cover portion 12 is made of a metal material or the like that can reflect the transmitted waves without allowing them to pass through, the presence of the upper cover portion 12 makes it less likely for the antenna's radiation pattern to be disturbed or the radiation efficiency to decrease. Consequently, the range of the transmitted waves can be extended.

[0051] Furthermore, in the sensor node 10 of this embodiment, a plate-like space Sb is provided between the outer surface of the bottom plate portion 11a of the frame portion 11 and the inner flat portion 15a of the lower cover portion 15, extending to near the peripheral edges of both surfaces. As a result, between the internal space Sa in which the control module 23 and the wireless module 24 are housed and the lower cover portion 15 which transmits heat input from the outside to the heat receiving side substrate 31 of the Peltier unit 30, a plate-like space Sb is interposed, in addition to the bottom plate portion 11a of the frame portion 11, extending to near the peripheral edges of the outer surface of the bottom plate portion 11a and the inner flat portion 15a of the lower cover portion 15. Therefore, the air present in this plate-like space Sb increases the thermal conductivity resistance between the bottom plate 11a and the lower cover 15, functioning as an insulating layer. This makes it even more difficult for heat input from the outside to the lower cover 15 to be transferred to the internal space Sa where the control module 23 and other components are housed, thus further preventing the control module 23 and wireless module 24 from being exposed to high temperatures. Consequently, the failure rate of the control module 23 and wireless module 24 can be further reduced. Furthermore, if the plate shape is small enough to fit within the range of this plate-like space Sb, a relatively large Peltier unit can be housed.

[0052] In the embodiment described above, the frame portion 11 was constructed by integrally molding the bottom plate portion 11a and the peripheral wall portion 11b so that they are connected. However, the bottom plate portion 11a and the peripheral wall portion 11b may be constructed separately (or divided) as long as they can be connected in a way that allows for thermal coupling. Furthermore, if the bottom plate portion 11a and the peripheral wall portion 11b are constructed separately, the peripheral wall portion 11b may be made of a resin material with good heat resistance and electromagnetic wave transmission properties. As a result, if the antenna 26 housed in the internal space Sa has a radiation pattern directed toward the peripheral wall portion 11b, the transmitted waves radiated from the antenna 26 in that direction can pass through such a resin peripheral wall portion 11b and be radiated into the external space Sc. Therefore, the range of the transmitted waves radiated from the antenna 26 with such a radiation pattern can be extended.

[0053] Furthermore, in the above-described embodiment, a configuration was adopted in which a horizontally elongated rectangular plate body lower cover portion 15 was used as the heat receiving portion. However, any member capable of transferring heat input from an external heat source such as the motor 101 to the heat receiving side substrate 31 of the Peltier unit 30 may be used as the heat receiving portion, such as a rod having a rectangular or cylindrical shape, or a frustum having a truncated pyramid or truncated cone shape.

[0054] Furthermore, in the above-described embodiment, the Peltier unit 30 is housed in the plate-shaped space Sb between the bottom plate portion 11a and the lower cover portion 15 of the frame portion 11, and the Peltier unit 30 is attached to the frame portion 11 that houses the printed circuit board 21. However, for example, a configuration may be adopted in which the Peltier unit 30 is removed to the outside without being attached to the frame portion that houses the printed circuit board 21.

[0055] As shown in Figure 6, the sensor node 60 is configured in almost the same way as the sensor node 10 described above, except that the Peltier unit 30 is brought out to the outside. Therefore, in Figure 6, the same reference numerals are used for components that are substantially the same as those of the sensor node 10 described with reference to Figures 1 to 5, and their explanation is omitted. Figure 6(A) shows a front view of the sensor node 60, and Figure 6(B) shows a cross-sectional view of the sensor node 60. Also, in these figures, the window member 13 is colored gray for the convenience of drawing representation.

[0056] The frame portion 61 has the same shape and material as the frame portion 11 of the sensor node 10, and is composed of a bottom plate portion 61a and a peripheral wall portion 61b. However, in the sensor node 60, the printed circuit board 21 is attached to the bottom plate portion 61a instead of the top cover portion 12. For this reason, the bottom plate portion 61a has four female screw holes (not shown) into which bolts 17 can be screwed. Also, in the top cover portion 12 of the sensor node 60, the window member 13 is positioned in an area that covers the entire antenna 26 in a front view of the top cover portion 12 when the printed circuit board 21 is attached to the bottom plate portion 61a. Therefore, compared to the front view of the sensor node 10 shown in Figure 2(A), it can be seen that in the sensor node 60 the window member 13 is located below the plane of the paper. Note that the top cover portion 12 may be made entirely of a resin material with good electromagnetic wave transmission characteristics instead of a metal material such as aluminum.

[0057] Furthermore, the outer surface of the bottom plate portion 61a of the frame portion 61 is formed to be almost entirely flat. Although there is no need to input heat from the outside (motor 101, piping 102, industrial furnace 103, etc.) to the outer surface of the bottom plate portion 61a, it is made flat so that it can be attached to non-heat-generating parts such as the motor 101 or placed around the motor 101. In addition, the frame portion 61 has female screw holes 61d formed near the four corners into which bolts 16 that pass through the through holes 12c of the upper cover portion 12 can be screwed. As a result, the upper cover portion 12 is fixed by screw fastening the female screw holes 61d of the frame portion 61 with four bolts 16.

[0058] In Figure 6(B), the reference numerals 61c, 61c', and 61c'' correspond to the stepped portion 11c, the upper part 11c', and the lower part 11c'' of the sensor node 10, respectively. Reference numeral 61e corresponds to the wiring hole 11e of the sensor node 10. However, in the sensor node 60, three wires 42, 43, and 51 need to be routed from the printed circuit board 21 through this wiring hole 61e into the external space Sc. Therefore, the wiring hole 61e is not a round hole but an elongated hole through which three wires can be inserted.

[0059] Two wires 41, a positive wire 42 and a negative wire 43, extend from the printed circuit board 21. The ends of these wires 41 are connected to a Peltier unit 30, and the length of the wires 41 is determined based on the respective placement positions of the sensor node 60 and the Peltier unit 30. In this embodiment, a heat sink 70 is attached to the heat dissipation side substrate 32 of the Peltier unit 30.

[0060] The heat sink 70 is made of a metal such as aluminum and consists of a base 71 formed in a nearly square shape larger than the square shape of the heat dissipation substrate 32, and a number of rod-shaped fins 73 arranged in a matrix on one side of the base 71. The Peltier unit 30 is thermally coupled to the other flat surface of the base 71, with the heat dissipation substrate 32 attached to it. The heat receiving substrate 31 of the Peltier unit 30 is attached to a high-temperature heat source such as a motor 101 for power, a pipe 102 through which a high-temperature fluid flows, or an industrial furnace 103 such as a heat treatment furnace. A heat receiving plate may be attached to the heat receiving substrate 31, and the Peltier unit 30 may be attached to the heat source with the heat receiving plate interposed between the heat receiving substrate 31 and the heat source.

[0061] In this configuration, the sensor node 60 can be positioned away from the heat source, making it difficult for heat to enter the frame 61 from the outside. This effectively prevents the control module 23 and wireless module 24 housed in the internal space Sa from being exposed to high temperatures. Consequently, performance degradation and failures caused by exposure of the electronic components constituting the control module 23 and wireless module 24 to high temperatures become even less likely, thus reducing the failure rate of the control module 23 and wireless module 24.

[0062] Furthermore, in the sensor node 60 configured in this way, the upper cover portion 12 is made of a resin material with good heat resistance and electromagnetic wave transmission properties that allows the transmitted waves output by the wireless module 24 to pass through, specifically the portion that covers the antenna 26 of the wireless module 24 when viewed from the front orthographic projection. Therefore, compared to the case where the upper cover portion 12 is made of a metal material or the like that can reflect the transmitted waves without allowing them to pass through, as in the sensor node 10, the presence of the upper cover portion 12 makes it less likely for the antenna's radiation pattern to be disturbed or the radiation efficiency to decrease, thus extending the range of the transmitted waves.

[0063] Furthermore, the sensor node 60 described above can be understood as a creative invention of a technical concept: "an information transmission device that wirelessly transmits information input from an external input, comprising: a thermoelectric conversion unit having a heat receiving side and a heat dissipation side, which generates electricity and outputs DC power when there is a temperature difference between these two sides; a control unit that acquires and outputs the information from the external input; and a transmission unit that wirelessly transmits the information output from the control unit, wherein the control unit and the transmission unit are arranged at a position separated from the thermoelectric conversion unit without thermal coupling with the heat dissipation side of the thermoelectric conversion unit, and are driven by the DC power output from the thermoelectric conversion unit."

[0064] Although specific examples of the present invention have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples described above. Furthermore, the technical elements described in this specification or drawings exhibit technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Moreover, the technologies illustrated in this specification or drawings achieve multiple objectives simultaneously, and achieving even one of these objectives constitutes technical usefulness. The terms in parentheses in the [Explanation of Symbols] section are intended to clarify the correspondence between the terms used in each of the embodiments described above and the terms described in the claims. [Explanation of Symbols]

[0065] 10,60…Sensor node (information transmission device) 11,61…Frame section (heat dissipation section) 11a, 61a...Bottom plate part (bottom part) 11b, 61b...peripheral wall part 12…Top cover (lid) 13…Window components 15...Lower cover part (heat receiving part) 15a...Inner flat part (one end side) 15b...Outside flat part (other end side) 20...Circuit Unit 21…Printed circuit board 22…Composite Module 23…Control module (control unit) 24…Wireless module (transmitter) 25…Boost module 26… Antenna 30…Peltier unit 31…Heat receiving side board (heat receiving side) 32…Heat dissipation side substrate (heat dissipation side) 33…Peltier element (thermoelectric conversion part) 41, 45, 51… wiring 50...Sensor (external input) 70… Heatsink 80... Wireless node 90... Computer 101...Motor (heat source) 102... Piping (heat source) 103…Industrial furnace (heat source) Sa...interior space Sb... Plate-like space Sc…External space

Claims

1. An information transmission device that wirelessly transmits information input from an external input, A thermoelectric conversion unit having a heat receiving side and a heat dissipation side, which generates electricity and outputs DC power when there is a temperature difference between these two sides, A heat receiving unit having one end and the other end, the one end of which is thermally coupled to the heat receiving side of the thermoelectric conversion unit, transmits heat input from the outside to the other end to the heat receiving side, A heat dissipation section having a box shape with a bottom and no lid, the heat dissipation side of the thermoelectric conversion section is thermally coupled to the outside of the bottom, and the peripheral wall portion connected to or thermally connectable to the bottom is exposed to the external space so that the heat emitted from the heat dissipation side can be released to the external space, A cover portion that closes the opening surrounded by the peripheral wall portion, facing the bottom of the heat dissipation portion, A control unit that acquires and outputs the information from the external input, The system includes a transmitting unit that wirelessly transmits the information output from the control unit, The information transmission device is characterized in that the control unit and the transmitting unit are mounted inside the lid and housed in an internal space partitioned by the heat dissipation unit and the lid, and are driven by the DC power output from the thermoelectric conversion unit.

2. The information transmission device according to claim 1, characterized in that the lid portion, in whole or in part, of which the portion covering the antenna of the transmitting unit is made of a material that can allow the transmitted waves output by the transmitting unit to pass through.

3. The information transmission device according to claim 1 or 2, characterized in that a plate-like space is provided between the outer surface of the bottom of the heat dissipation section and the side surface of one end of the heat receiving section, extending to the vicinity of the peripheral edges of both surfaces.

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