Snowfall sensor and snow melting device

Abstract

To provide a snowfall sensor which ensures superior thermal insulation capability, and a snow melting device.SOLUTION: A snowfall sensor is provided, comprising a cover, a sensor unit provided inside the cover, and a first heater provided below the sensor unit inside the cover.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a snowfall sensor for detecting snowfall information and a snow melting device. [Background technology]

[0002] In regions where snowfall is common, snow melting devices are used to protect roads and sidewalks that are essential to daily life from snow damage. There is a demand for technology that uses a snowfall sensor to detect snowfall and automatically operates the snow melting device when a snowfall phenomenon that causes snow accumulation occurs (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-213755 A Summary of the Invention [Problem to be solved by the invention]

[0004] The snowfall sensors used to control such equipment have the advantages of being inexpensive, having high detection accuracy, and being less likely to go undetected, and are designed to detect the air temperature using a temperature sensor and to detect the number of snowflakes per certain period of time using a photoelectric sensor that emits infrared rays, which have a longer wavelength than visible light and are less likely to scatter, and receives the light reflected by the snowflakes.

[0005] In snowfall sensors, a photoelectric sensor, which is an electronic device, is installed inside a sealed casing with a window to prevent it from being affected by rain and wind, and a structure is used in which the photoelectric sensor detects snowflakes through the window. If snow accumulates on the window and blocks it, snowflake detection becomes impossible, so a heat retention heater is installed inside the casing of the snowfall sensor, and when the air temperature detected by the temperature sensor falls below a certain temperature, electricity is applied to the heat retention heater, and when the air temperature rises above the certain temperature, electricity is stopped.

[0006] Since the heat retention heater generates a high heat temperature, if it is installed in direct contact with the window or the casing part around the window, the window or the casing part is likely to be thermally deformed. Therefore, by installing the heat retention heater inside the casing without touching the window or the casing part around the window, the space inside the casing is heated by the heat retention heater and the heater heat is transferred to the window or the casing, preventing snow from accumulating on the window. In order to assist the transfer of heat, a heat dissipation member may be placed between the window or the cover and the heater. However, in a configuration in which the heat dissipation member is placed inside the cover, the number of parts increases, which reduces productivity, and the cover becomes larger by the space for the heat dissipation member. Therefore, there are problems such as an increase in the area where snow accumulates and the need to increase the heat amount of the heat retention heater accordingly.

[0007] An object of the present invention is to provide a snowfall sensor and a snow melting device that can ensure high heat retention performance. [Means for solving the problem]

[0008] A snowfall sensor according to one aspect of the present invention includes: The device comprises a body, a cover having a window portion that transmits light, a casing having a sensor portion provided within the cover and a partition plate, and a first heater provided within the cover below the sensor portion, wherein the partition plate divides the space of the casing into an upper first chamber and a lower second chamber, a substrate is disposed in the first chamber and the partition plate holds the substrate, the substrate divides the first chamber into front and rear, the first heater is provided within the cover, in a lower region or below the window portion, on the same side as the sensor portion with respect to the substrate, in the first chamber divided into front and rear by the substrate, and the sensor portion and the first heater are disposed in the region between the substrate and the window portion. Effect of the Invention

[0009] According to the present invention, it is possible to provide a snowfall sensor and a snow melting device that can ensure a high heating effect. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is an explanatory diagram showing the configuration of a snow melting device according to a first embodiment of the present invention. [Diagram 2] FIG. 4 is a cross-sectional view showing the configuration of a snowfall sensor of the snow melting device. [Diagram 3] FIG. [Figure 4] FIG. [Diagram 5] FIG. 2 is an explanatory diagram showing the circuit configuration of the snowfall sensor. [Figure 6] FIG. 11 is a cross-sectional view showing the configuration of a snowfall sensor according to another embodiment of the present invention. [Figure 7] FIG. 11 is a cross-sectional view showing the configuration of a snowfall sensor according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] A snow melting device 100 and a snowfall sensor 1 according to one embodiment of the present invention will be described below with reference to Figs. 1 to 5. Fig. 1 is an explanatory diagram of the snow melting device 100 according to the first embodiment. Fig. 2 is a cross-sectional view of the internal configuration of the snowfall sensor 1 as seen from the side, and Fig. 3 is a cross-sectional view of the internal configuration of the snowfall sensor 1 as seen from the front. Fig. 4 is a cross-sectional view of the internal configuration of the snowfall sensor 1 as seen from above. Fig. 5 is an explanatory diagram showing the circuit configuration of the snowfall sensor.

[0012] 1, the snow melting device 100 includes a snowfall sensor 1, a snow melting device 2, and a control device 3. The snow melting device 100 is a device that melts snow present in a snow melting target location, such as a road.

[0013] The snowfall sensor 1 includes a casing 10, a control board 11, a first temperature sensor 12, a distance measuring sensor 13 as a sensor unit, multiple heaters 14A, 14B, multiple cables 15a, 15b, and a second temperature sensor 16. The snowfall sensor 1 is installed, for example, outdoors, detects snowfall information in a target area As, and sends an operation signal for the snow melting equipment 2 to the control device 3. The snowfall sensor 1 also receives power supply from the control device 3 that operates the snow melting equipment 2. The snowfall sensor 1 may further include a remote control 4 for remote operation.

[0014] The casing 10 includes a body 17, a cover 18, and partition plates 19a and 19b.

[0015] The body 17 is cylindrical with openings at the top and bottom. An antenna mast is inserted into the opening at the bottom of the body 17 and the body 17 is connected to the antenna mast. The body 17 forms a base for supporting the snow sensor 1 at the installation location. A first partition plate 19a is disposed in a circular opening 17a formed at the top end of the body 17. A second partition plate 19b is disposed midway in the axial direction of the body 17.

[0016] Cable holes 17c penetrating the peripheral wall are formed in two places above the position where the partition plate 19b is disposed in the body 17. The cable holes 17c are circular through-holes into which the connection cables 15a, 15b are inserted.

[0017] The cover 18 is made of, for example, a synthetic resin material, and has a roof portion 18a and a flange portion 18b formed integrally therewith. The cover 18 is open on the lower side, and the upper end portion of the body 17 is inserted into the flange portion 18b, and the periphery is joined by being watertightly glued.

[0018] The roof portion 18a is made of, for example, a light-transmitting synthetic resin material and is configured in a hemispherical dome shape that opens downward. The roof portion 18a has a rectangular window portion 18c in the center of the front portion. The window portion 18c is configured in a flat plate shape and is configured to be able to transmit light from the distance measuring sensor 13. The window portion 18c is made of a light-transmitting material and is thinner than the surrounding areas of the roof portion 18a, for example, with a thickness of about 1 mm. The outer surface of the roof portion 18a has a curved shape that allows snow that falls from above to easily fall off without accumulating.

[0019] The inner wall of the roof portion 18a is formed with a protrusion 18e that forms an engagement surface that engages with the periphery of the control board.

[0020] The partition plates 19a and 19b are formed of, for example, a synthetic resin material or a rubber material, and have a circular plate-like outer shape. The partition plates 19a and 19b are arranged along a plane perpendicular to the axis of the body 17. As shown in FIG. 3, the upper partition plate 19a is provided at the connection portion between the cover 18 and the body 17, and covers the opening 17a at the upper end of the body 17. The partition plate 19a is formed, for example, in a circular shape, and has a slit extending in the radial direction in the center and through which the control board 11 passes. The partition plate 19a divides the space inside the casing 10 into an upper first chamber 20a and a lower second chamber 20b, and holds the control board 11, preventing the sensor and the control board 11 from falling. That is, the partition plate 19a divides the interior of the storage space formed by the roof portion 18a and the body 17 and accommodating the control board 11 in the vertical direction, and the partition plate 19a and the roof portion 18a form a first chamber 20a that accommodates the distance measuring sensor 13 and part of the control board 11. The first chamber 20a is also divided into front and rear by the control board 11.

[0021] Partition plate 19b is provided at an axial midway point in the internal space of body 17. Partition plate 19b is disposed below partition plate 19a and control board 11. Partition plate 19b divides the space within body 17 into a second chamber 20b that houses control board 11, and a third chamber 20c formed below second chamber 20b. Partition plate 19b prevents raindrops from entering through a hole at the bottom end of body 17.

[0022] The control board 11 is a circuit board and is erected inside the casing 10. The control board 11 is arranged from the space inside the cover 18 to the space inside the body 17. The control board 11 is a plate-like member having a rectangular first base portion arranged inside the body 17 and a second base portion having an arc-shaped edge that matches the shape of the cover 18, which are continuous and integrated together. A notch is formed at the boundary between the first base portion and the second base portion, which is engaged with and supported by the outer edge of the partition plate 19a.

[0023] On the control board 11, various control devices such as a storage unit 21, a sensor control unit 25, a first temperature sensor 12, a second temperature sensor 16, etc. are mounted.

[0024] The storage unit 21 includes, for example, a RAM and a ROM, and stores various set values ​​and arithmetic expressions. For example, the storage unit 21 stores information such as the distance sent from the distance measuring sensor 13 and the temperature sent from the temperature sensor 12 as snowfall information.

[0025] The first temperature sensor 12 includes, for example, a temperature detection element, detects temperature information, and sends the detected signal to the sensor control unit 25. For example, the first temperature sensor 12 is provided on the cable 15b and detects the air temperature. The first temperature sensor 12 may also be mounted on the control board 11.

[0026] The second temperature sensor 16 is disposed in a location to be melted snow, such as a road, and detects the ground temperature. The second temperature sensor 16 includes, for example, a temperature detection element and a sensor case. The second temperature sensor 16 detects the temperature information of the road and sends the detected signal to the sensor control unit 25.

[0027] The distance measurement sensor 13 is, for example, a triangulation type photoelectric sensor. The distance measurement sensor 13 includes a sensor case 22, a light projecting unit 23 mounted on the sensor case 22, and a light receiving unit 24. The sensor case 22 of the distance measurement sensor 13 is screwed onto the control board 11 and disposed in a position facing the window portion 18c. The distance measurement sensor 13 is connected to a sensor control unit 25 provided on the control board 11.

[0028] For example, the distance measuring sensor 13 measures the distance to a target (object) arranged in a detection area including a long distance of up to about 1 m. For example, the detection area is set to an area within a certain distance from a cone-shaped irradiation area spreading forward from the light projecting unit 23 and the light receiving unit 24.

[0029] The light projecting unit 23 includes an emitter that projects invisible light in a cone shape. For example, the light projecting unit 23 projects pulsed infrared light as invisible light at regular intervals. The invisible light is, for example, near-infrared light in the invisible light region with a wavelength of 800-1200 nm, specifically, a wavelength of about 940 nm.

[0030] The light receiving unit 24 includes a detection element that receives light reflected by the target. For example, the light receiving unit 24 includes a plurality of detection elements arranged in an array.

[0031] The first heater 14A and the second heater 14B are provided in the first chamber 20a, for example, in the lower region of the first chamber 20a. For example, in the first chamber 20a, the first heater 14A is arranged below the distance measuring sensor 13 and the window portion 18c, and the second heater 14B is arranged above the distance measuring sensor 13 and the window portion 18c. The heaters 14A and 14B are provided in the region between the control board 11 and the window portion 18c. The heaters 14A and 14B have heating elements that generate heat when a voltage is applied, and are operated and generate heat under the control of a sensor control unit 25 fixed to the control board 11. The heaters 14A and 14B prevent snow from accumulating on the window portion 18c due to heat generation. For example, the heaters 14A and 14B are heater devices of the same model. For example, the heaters 14A and 14B are connected in parallel.

[0032] The heaters 14A and 14B are arranged such that the output of the first heater disposed below is greater than the output of the second heater disposed above. The heaters 14A and 14B are arranged in the front space of the first chamber 20a partitioned into front and rear by the control board 11, that is, on the same side as the distance measuring sensor 13 with respect to the control board 11. In this embodiment, the heaters 14A and 14B are arranged one above and one below, and the output of the first heater 14A disposed below is set to be greater than the output of the second heater 14B disposed above. That is, for example, if the output of the first heater is R2 and the output of the second heater is R1, R2>R1. Therefore, the heat dissipation amount of the first heater 14A is greater than the heat dissipation amount of the second heater 14B.

[0033] The connection cables 15a and 15b each have, for example, a power supply line and a signal line. One of the connection cables 15a passes through a cable hole 17c of the body 17, one end of which is connected to the control board 11 in the housing, and the other end of which is led out of the housing and connected to the control device 3. The other connection cable 15b passes through the cable hole 17c, one end of which is connected to the control board 11 in the housing, and the other end of which is led out of the housing, and the other end of the connection cable 15b is connected to the second temperature sensor 16. The ends of the connection cables 15a and 15b that are disposed in the cable hole 17c are provided with a pipe member 15d that covers the outer surface.

[0034] The sensor control unit 25 includes, for example, a CPU, various processing circuits, a conversion circuit, etc. The sensor control unit 25 controls the operation of the snowfall sensor 1 and the snow melting device 2 according to information sent from the light receiving unit 24 and the temperature sensor 12 and various programs stored in advance in the storage unit 21.

[0035] The sensor control unit 25 is connected to the distance measurement sensor 13, and causes the light-projecting unit 23 to emit infrared light under specified conditions, and based on the signal detected by the light-receiving unit 24, measures the distance to a target present in the target area and detects measurement information.

[0036] For example, the sensor control unit 25 detects snowfall information based on the detection results of the first temperature sensor 12, the distance measurement sensor 13, and the second temperature sensor 16. For example, the sensor control unit 25 calculates the number of snowflakes (snowflake count number) based on the number of times the distance to the target is detected in the target area As and on the distance information. As an example, the sensor control unit 25 calculates the number of snowflakes by counting the number of times the distance measurement sensor 13 detects the distance to the target within a specified area as the number of snowflakes. The sensor control unit 25 detects signals from the temperature sensors 12, 16 and the distance measurement sensor 13, and judges the snowfall state based on the temperatures detected by the temperature sensors 12, 16 and the information on the number of snowflakes per hour obtained from the signal from the distance measurement sensor 13, and sends an operation signal to the control device 3.

[0037] Then, the sensor control unit 25 operates the snow melting device 2 when the operating conditions of the snow melting device 2 are met based on the number of snowflakes and the temperature information, and sends an operation signal to the control device 3 to stop the snow melting device 2 when the stop conditions of the snow melting device 2 are met. For example, the sensor control unit 25 operates the snow melting device 2 when the number of snowflakes per certain time in the target area As exceeds a predetermined value, and sends a signal to the output board 35 of the control device 3 to stop the snow melting device 2 when the number of snowflakes per certain time in the target area As falls below a predetermined stop reference number. In addition, the sensor control unit 25 may stop the power supply to the distance measurement sensor 13 and turn off the operation signal to the control device 3 when the air temperature detected by the temperature sensor 12 rises to or above the stop reference temperature T2 (e.g., T1+0.5°C, 3.0°C). In addition, the sensor control unit 25 may control the drive of the distance measurement sensor 13 based on the temperatures detected by the temperature sensors 12 and 16. For example, when the detected temperature is below a certain temperature, the distance measuring sensor 13 is operated to irradiate pulsed infrared light from the light projecting section 23 of the distance measuring sensor 13, and the irradiation is stopped when the air temperature rises to a certain value.

[0038] The sensor control unit 25 also controls the driving of the heaters 14A and 14B based on the temperatures detected by the various temperature sensors 12. For example, the sensor control unit 25 obtains a signal from the temperature sensor 12, and drives the heater 14 when an operating condition for the heater 14 is satisfied based on the temperature information from the temperature sensor 12, or stops the heater 14 when a stop condition for the heater 14 is satisfied. As an example, when the air temperature detected by the temperature sensor 12 falls below a predetermined heater operation first temperature T3 (e.g., 3.0°C), the sensor control unit 25 energizes the heater 14, and when the air temperature rises to a predetermined heater stop temperature T4 (e.g., 4.0°C), the sensor control unit 25 stops the energization of the heater 14.

[0039] For example, the sensor control unit 25 may adjust the output based on the temperature condition, and may control the operation with, for example, a plurality of stages of output. That is, for example, when the air temperature becomes equal to or lower than a preset heater operation temperature T3, a voltage is applied to the heaters 14A and 14B for a preset time with a preset first output, for example, a duty of 50%, and when the air temperature becomes equal to or lower than a heater operation second temperature T5 set lower than the heater operation temperature T3, a voltage is applied with a second output higher than the first output, for example, a duty of 100%. Then, when the detected temperature rises by a preset temperature from or lower than the heater operation second temperature T5 and rises to or higher than a reference temperature T6 higher than the heater operation second temperature T5, the output is reduced, and, for example, a voltage is applied with a preset first output. As an example, the reference temperature T6 for reducing the output is set to a temperature lower than the heater stop temperature T4 and higher than the heater operation temperature T3 and the heater operation second temperature T5. Furthermore, when the air temperature increases by a predetermined temperature and reaches a predetermined heater stop temperature T4, the sensor control unit 25 stops the application of voltage to the heaters 14A and 14B.

[0040] As shown in FIG. 1, the snow melting device 2 is installed at a location where snow is to be melted, for example, on a road. For example, in the case of a sprinkler type structure in which groundwater is pumped up and used as water for melting snow, the snow melting device 2 is equipped with a snow melting pump. The snow melting device 2 performs a sprinkling operation to melt the snow at the location to be melted, for example, on the road, in response to a signal output from the control device 3. The signal is, for example, a signal (ON signal) that directly starts the snow melting pump. In the snow melting device 100, the snow melting device 2 is operated in response to the signal, and snow melting water is sent to the pipes and sprinkled on the road, melting the snow on the road.

[0041] As a specific example, the control device 3 outputs a signal to control the snow melting device 2, and performs a water sprinkling operation to melt snow in the location to be melted, for example, on the road. The signal is a signal (ON signal) that directly starts the snow melting pump. The snow melting device 2 is operated by the signal output from the control device 3, and sends snow melting water to the pipes and sprinkles it on the road, melting the snow on the road. The control device 3 includes a display unit 33, an operation unit 34, and an output board 35. The control device 3 is connected to the snowfall sensor 1 via a connection cable 15a so as to be able to supply power and transmit and receive signals. The control device 3 supplies power (electricity) to the snowfall sensor 1 via the connection cable 15a, and controls the operation of the snow melting device 2 according to an operation signal sent from the snowfall sensor 1. For example, the control device 3 is connected with three wires via the connection cable 15a: a DC power supply, an operation signal, and 0V.

[0042] The display unit 33 is a display that displays information such as temperature information and the number of snowflakes. The operation unit 34 includes input devices such as a power switch and various operation buttons.

[0043] The output board 35 is, for example, a circuit board, and is equipped with various control devices. The output board 35 has, for example, an operation circuit that switches ON / OFF an operation relay that operates the snow melting device according to an operation signal from the snowfall sensor, an opening / closing relay that opens and closes a solenoid valve according to an operation signal from the snowfall sensor, and a DC power supply unit that rectifies AC power and supplies DC to the snowfall sensor. The control device 3 operates the snow melting device 2 according to the operation signal from the snowfall sensor 1.

[0044] The snowfall sensor 1 device according to the embodiment described above provides the following effects. That is, by providing a heater below the first chamber 20a, which is the space that houses the distance measurement sensor 13, convection can be utilized, resulting in energy saving effects. Also, by providing a heater 14B above the distance measurement sensor 13, the space can be effectively heated and snow can be prevented from accumulating on the cover 18. Also, by providing heaters 14A and 14B in the same space as the distance measurement sensor 13, which is arranged opposite the window portion 18c, within the first chamber 20a, which is divided into multiple compartments, the window portion 18c can be effectively heated.

[0045] Furthermore, by increasing the output of the lower heater 14A, convection can be generated effectively, resulting in a high energy saving effect.

[0046] Also, by using the same model for the multiple heaters 14A, 14B, it is possible to reduce the number of component types and prevent mounting errors during production. Furthermore, if a heater breaks down or is disconnected, in the case of a series connection, voltage application to all heaters may stop in the event of a disconnection, but in the above embodiment, by connecting heaters in parallel, a constant voltage application can be assumed at all times, ensuring a constant heat retention effect.

[0047] The present invention is not limited to the above embodiment. For example, various set values ​​and reference values ​​for calculation can be changed as appropriate.

[0048] For example, in the above embodiment, one heater 14A and one heater 14B are provided at each of the lower and upper parts, but this is not limited to this. For example, as another embodiment, as shown in FIG. 6, a snowfall sensor 1A may be provided with no heater on the upper side and only the first heater 14A on the lower side. In this case, the heat of the heater 14A on the lower side rises, thereby effectively heating the space. In addition, there may be a plurality of heaters 14A and / or 14B. For example, as another embodiment, a snowfall sensor 1B shown in FIG. 7 is configured to have two first heaters 14A and one second heater 14B. In these cases, the heat of the heater 14A on the lower side rises, thereby generating convection in the first chamber 20a in the cover 18, and the window portion 18c can be effectively heated.

[0049] In addition, for example, when the number of heaters 14A is greater than the number of heaters 14B as shown in FIG. 7, by connecting the heaters 14A and 14B in parallel and driving them with the same output, the output of the lower heater 14A will be greater than the output of the upper heater 14B, and convection can be effectively utilized.

[0050] In the above embodiment, the output of the lower heater is increased, but this is not limited to the above. For example, when the first heater 14A and the second heater 14B are provided on the top and bottom, respectively, the output of the first heater 14A and the second heater 14B may be the same, i.e., the amount of heat radiation may be the same. In this case, too, the heat of the lower heater 14A rises, generating convection and effectively heating the space.

[0051] The snowfall sensor 1 may be configured to be capable of wireless communication with low power consumption using a system such as Bluetooth (registered trademark).

[0052] In the above embodiment, the snow melting device 100 is configured to pump up groundwater using a pump, but the present invention is not limited to this. For example, a sprinkler system that supplies snow melting water from a general water supply pipe, or a snow melting device that does not sprinkle water, such as a heater, may be used.

[0053] The present invention is not limited to the above-mentioned embodiment, and can be modified in various ways without departing from the gist of the present invention. The embodiments may be combined as appropriate, and in that case, the combined effect can be obtained. Furthermore, the above-mentioned embodiment includes various inventions, and various inventions can be extracted by combinations selected from the multiple components disclosed. For example, if the problem can be solved and the effect can be obtained even if some components are deleted from all the components shown in the embodiment, the configuration from which the components are deleted can be extracted as an invention. The following is a description equivalent to the invention described in the claims of the original application. (1) Cover and A sensor unit provided within the cover; A snowfall sensor comprising: a first heater provided within the cover below the sensor portion. (2) The cover has a window portion that transmits light, The first heater is provided in the cover in a lower region of the first chamber in which the sensor unit is provided or below the window unit. A snowfall sensor as described in (1). (3) The snow sensor according to (2), wherein a substrate is disposed in the first chamber, and the sensor portion and the first heater are disposed in the area between the substrate and a window portion. (4) A snowfall sensor according to any one of (1) to (3), comprising a second heater arranged above the sensor unit. (5) The snow sensor according to any one of (1) to (4), comprising a plurality of the first heaters. (6) The snow sensor according to (4), wherein the output of the first heater arranged below is greater than the output of the second heater arranged above. (7) The snow sensor according to (4), wherein the heaters are connected in parallel. (8) A snowfall sensor according to (2), A snow melting device comprising: a snow melting device connected to the snowfall sensor. [Explanation of symbols]

[0054] 1...snowfall sensor, 2...snow melting equipment, 3...control device, 4...remote control, 10...casing, 11...control board, 12...temperature sensor, 13...distance measurement sensor, 14A, 14B...heater, 15a...connection cable, 15b...connection cable, 15d...pipe component, 16...temperature sensor, 17...body, 17a...opening, 17c...cable hole, 18...cover, 18a...roof portion, 18b...flange portion, 18c...window portion, 18e...protrusion portion, 19a, 19b...partition plate, 19c...slit, 20a...first chamber, 20b...second chamber, 21...memory portion, 22...sensor case, 23...light-emitting portion, 24...light-receiving portion, 25...sensor control portion, 33...display portion, 34...operation portion, 35...output board, 100...snow melting device.

Claims

1. A casing including a body, a cover having a light-transmitting window, a sensor unit provided within the cover, and a partition plate; a first heater provided within the cover below the sensor unit; Equipped with The partition plate divides the space of the casing into an upper first chamber and a lower second chamber, A substrate is disposed in the first chamber; The partition plate holds the substrate, the substrate divides the first chamber into front and rear portions, the first heater is provided in the cover, in the first chamber which is divided into front and rear by the substrate, on the same side as the sensor unit with respect to the substrate, in a lower region or below the window portion; the sensor portion and the first heater are disposed in a region between the substrate and the window portion; Snowfall sensor.

2. A snowfall sensor as described in claim 1, wherein an engagement surface is formed on the inner wall of the roof portion of the cover to engage with the peripheral edge of the substrate.

3. A snowfall sensor as described in claim 1, wherein the substrate is positioned penetrating the partition plate.

4. a second heater disposed above the sensor portion; The heaters are connected in parallel, 4. The snow sensor according to claim 1, wherein an output of the first heater disposed below is greater than an output of the second heater disposed above.

5. The snow sensor according to claim 1 , further comprising a plurality of the first heaters.

6. Equipped with a temperature sensor for detecting air temperature, The snowfall sensor of claim 4, further comprising a control unit that starts switching current for the first heater and the second heater for a time period of a preset first duty ratio when the air temperature detected by the temperature sensor drops below a predetermined heater operation first temperature, changes switching current to a time period of a second duty ratio greater than the first duty ratio when the air temperature drops below a heater operation second temperature set lower than the heater operation first temperature, changes switching current to a time period of the first duty ratio when the air temperature rises above a reference temperature set higher than the heater operation first temperature, and stops switching current when the air temperature rises above a heater stop temperature set higher than the reference temperature.

7. A snow sensor according to any one of claims 1 to 6, A snow melting device comprising: a snow melting device connected to the snowfall sensor.

Images