JP2017225264A - Device and heat generation structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate a heat of a motor in a static state by a current from a main electric power.SOLUTION: A device comprises: a stepping motor 11 having a coil 111; a driver 12 supplying a current to the coil 111; a thermistor 13 measuring a temperature of the circumference; a temperature acquisition part 141 that acquires information indicating the temperature measured by the thermister 13; a temperature determination part 142 that determines whether the temperature is the existed value or less from the information indicating the temperature acquired by the temperature acquisition part 141; and a driver control part 143 commanding that the current making the coil 111 generated supplies to the coil 111 supplying at the time of the stoppage of the current for the driver 12 in a case where it is determined that the temperature is the existed value or less by the temperature determination part 142.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a device and a heat generation structure for generating heat in a stationary motor.

  In a device with a built-in motor, if the operating environment temperature is low and the internal temperature of the device is lower than the lower limit temperature of use of a component built in the device, there is a risk that malfunction of the component will occur. In view of this, a structure has been conventionally known in which a stationary motor is heated to increase the internal temperature of the device and avoid the occurrence of malfunction of components due to low temperatures (see, for example, Patent Document 1). In the structure disclosed in Patent Document 1, a brush motor is used, and when the main power source and the coil are shut off, a direct current is generated so that the rotor maintains a stationary state and the coil generates heat at a predetermined temperature. A heat generating means for supplying to is provided.

Japanese Utility Model Publication No. 5-66442

  However, conventionally, a brush motor is used, and there is a problem that a heating means for supplying a direct current to the coil is required separately from the main power source. As a result, it becomes an obstacle to increase in cost and downsizing of the device. In addition, although the method of raising the internal temperature of an apparatus using a heater instead of the heat_generation | fever of a motor is also considered, cost also increases in this case and becomes an obstacle of size reduction of an apparatus.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a device capable of generating heat in a stationary motor by a current from a main power source.

  A device according to the present invention is provided in a housing, and acquires a stepping motor having a coil, a driver that supplies a current to the coil, a thermistor that measures the temperature in the housing, and information indicating the temperature measured by the thermistor. And a temperature determination unit for determining whether the temperature is equal to or lower than a predetermined value from the information indicating the temperature acquired by the temperature acquisition unit, and the temperature determination unit determines that the temperature is equal to or lower than the predetermined value. And a driver control unit that instructs the driver to supply a current that causes the coil to generate heat to the coil that supplies the current during the stop.

  According to the present invention, since it is configured as described above, the motor in a stationary state can be heated by the current from the main power source.

It is a block diagram which shows the structural example of the heat generating structure which concerns on Embodiment 1 of this invention. It is a flowchart which shows the operation example of the control part in Embodiment 1 of this invention. It is a figure which shows the example of supply of the electric current to the stepping motor in Embodiment 1 of this invention. 4A and 4B are diagrams showing a configuration example of the surveillance camera device according to Embodiment 2 of the present invention, and are a perspective view and a partially transparent front view as viewed in A. FIG. 5A and 5B are diagrams showing a configuration example of a surveillance camera device according to Embodiment 3 of the present invention, and are a perspective view and a partially transparent front view as viewed in B. FIG. It is a partially transparent front view which shows the structural example of the surveillance camera apparatus which concerns on Embodiment 5 of this invention. It is a partially transparent front view which shows the structural example of the surveillance camera apparatus which concerns on Embodiment 6 of this invention. It is a partially transparent front view which shows the structural example of the surveillance camera apparatus which concerns on Embodiment 7 of this invention. It is a perspective view which shows the structural example of the pan motor in Embodiment 8 of this invention. 10A and 10B are diagrams showing a hardware configuration example of the control unit in the first to eighth embodiments of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a block diagram showing a configuration example of a heat generating structure 1 according to Embodiment 1 of the present invention.
As shown in FIG. 1, the heat generating structure 1 includes a stepping motor 11, a driver (main power source) 12, a thermistor 13, and a control unit 14.

  The stepping motor 11 is a motor having a rotor (not shown) made of permanent magnets and a plurality of coils 111 arranged around the rotor in a non-contact manner with the rotor. A current (excitation current) is sequentially supplied to each coil 111, thereby generating a rotating magnetic field and rotating the rotor in one direction. In the heat generation structure 1 according to the first embodiment, the coil 111 is also used as a heat generator.

The driver 12 drives the stepping motor 11 by supplying a current to the coil 111.
The thermistor 13 measures the ambient temperature.

  The control unit 14 controls the driver 12. When rotating the stepping motor 11, the controller 14 instructs the driver 12 to supply current (current during operation) to the coils 111 in order. Further, when the stepping motor 11 is stationary, the control unit 14 instructs the driver 12 to continue supplying current (stop current) only to the predetermined coil 111. Furthermore, the control unit 14 also has a function (heat generation function) for controlling the driver 12 so as to cause the coil 111 to generate heat based on the temperature measured by the thermistor 13. Hereinafter, the heat generation function by the control unit 14 will be described. As shown in FIG. 1, the control unit 14 includes a temperature acquisition unit 141, a temperature determination unit 142, and a driver control unit 143 as a heat generation function.

The temperature acquisition unit 141 acquires information indicating the temperature measured by the thermistor 13.
The temperature determination unit 142 determines from the information indicating the temperature acquired by the temperature acquisition unit 141 whether the temperature is equal to or lower than a predetermined value. Here, the predetermined value is, for example, a lower limit temperature of use limit of a part included in a device in which the heat generating structure 1 is built. In addition, after determining that the temperature is equal to or lower than the predetermined value, the temperature determination unit 142 determines whether the temperature is equal to or higher than the second predetermined value from information indicating the temperature acquired by the temperature acquisition unit 141. . Here, the second predetermined value is, for example, a usable temperature of a component included in a device in which the heat generating structure 1 is built, and is a temperature higher than the predetermined value.

  When the temperature determination unit 142 determines that the temperature is equal to or lower than the predetermined value, the driver control unit 143 causes the driver 111 to generate a current ( Command to supply current during heating. Thereafter, when the temperature determination unit 142 determines that the temperature has become equal to or higher than the second predetermined value, the driver control unit 143 stops the instruction to the driver 12.

Next, an operation example of the control unit 14 in Embodiment 1 will be described with reference to FIG. In the following description, it is assumed that the heat generating structure 1 is built in the device, the default value is the use limit lower limit temperature, and the second default value is the usable temperature.
In the operation example of the control unit 14, as shown in FIG. 2, first, the temperature acquisition unit 141 acquires information indicating the temperature (internal temperature of the device) measured by the thermistor 13 (step ST201). In addition, the acquisition process by the temperature acquisition part 141 is performed regularly.

Next, the temperature determination unit 142 determines whether the temperature is equal to or lower than a predetermined value from the information indicating the temperature acquired by the temperature acquisition unit 141 (step ST202). That is, the temperature determination unit 142 determines whether the internal temperature of the device is equal to or lower than the use limit lower limit temperature of the components included in the device.
In step ST202, when the temperature determination unit 142 determines that the temperature is not equal to or lower than the predetermined value, the sequence returns to step ST202 and enters a standby state.

  On the other hand, when the temperature determination unit 142 determines that the temperature is equal to or lower than the predetermined value in step ST202, the driver control unit 143 supplies the current to the coil 111 that supplies a current at the stop to the driver 12. Command to supply current for generating heat to coil 111 (heat generation current) is provided (step ST203). Then, the driver 12 supplies a heat generation current to the corresponding coil 111 in accordance with the command, and the coil 111 generates heat. Thereby, the internal temperature of an apparatus rises.

Thereafter, the temperature determination unit 142 determines whether the temperature is equal to or higher than the second predetermined value from the information indicating the temperature acquired by the temperature acquisition unit 141 (step ST204). In other words, the temperature determination unit 142 determines whether the internal temperature of the device is equal to or higher than the usable temperature of the components included in the device.
In step ST204, when the temperature determination unit 142 determines that the temperature is not equal to or higher than the second predetermined value, the sequence returns to step ST204 and enters a standby state.

  On the other hand, if the temperature determination unit 142 determines in step ST204 that the temperature is equal to or higher than the second predetermined value, the driver control unit 143 stops the command to the driver 12 (step ST205). Then, the driver 12 stops supplying the heat generation current to the corresponding coil 111.

Next, the transition of the current value from the stopped state to the operating state of the stepping motor 11 in the low temperature state will be described with reference to FIG. In FIG. 3, reference numeral 301 indicates the temperature measured by the thermistor 13. Reference numeral 302 indicates a current supplied from the driver 12 to the coil 111. Reference numeral 303 indicates the rated current value of the coil 111.
When the stepping motor 11 is stationary, the driver 12 continues to supply the stop-time current Ia to the predetermined coil 111 in order to maintain the rotational angle position of the stepping motor 11.

  Here, for example, when the internal temperature of the device in which the heat generating structure 1 is built is equal to or lower than the use lower limit temperature (for example, −10 ° C.) of the component included in the device, the driver control unit 143 instructs the driver 12 to Command to supply a current Ib during heat generation for causing the coil 111 to generate heat. Upon receiving this command, the driver 12 generates a current Ib at the time of heat generation necessary for raising the internal temperature of the device above the usable temperature of the component (for example, 0 ° C.) by the heat generated by the coil 111. Supply. At this time, the driver 12 supplies a current equal to or lower than the rated current value in order to protect the coil 111. The coil 111 that has received the heat generation current Ib generates heat, and the internal temperature of the device is raised so as to be equal to or higher than the usable temperature. This avoids the occurrence of malfunctions of parts due to low temperatures.

In addition, when the internal temperature of the device becomes equal to or higher than the usable temperature, the driver control unit 143 stops the supply of the heat generation current Ib to the driver 12. In this way, when the internal temperature of the device has risen sufficiently, it is not necessary to flow the current excessively by stopping the supply of the heat generation current Ib.
Thereafter, when the stepping motor 11 is rotated, the control unit 14 instructs the driver 12 to supply the operating current Ic as usual.

  As described above, according to the first embodiment, the stepping motor 11 having the coil 111, the driver 12 that supplies current to the coil 111, the thermistor 13 that measures the ambient temperature, and the thermistor 13 are used. A temperature acquisition unit 141 that acquires information indicating the temperature, a temperature determination unit 142 that determines whether the temperature is equal to or lower than a predetermined value from the information that indicates the temperature acquired by the temperature acquisition unit 141, and a temperature determination unit 142 A driver control unit 143 for instructing the driver 12 to supply a current that causes the coil 111 to generate heat to the coil 111 that is supplying the current at the stop when the temperature is determined to be equal to or lower than the predetermined value; Since it is provided, the stationary stepping motor 11 can be heated by the current from the driver (main power source) 12. As a result, it is not necessary to provide heat generating means separately from the main power supply, and thus there are effects of cost reduction and size reduction compared to the conventional configuration.

Embodiment 2. FIG.
In the second embodiment, an application example of the heat generation structure 1 according to the first embodiment will be described.
FIG. 4 is a diagram showing a configuration example of the monitoring camera device 2a according to Embodiment 2 of the present invention.
The surveillance camera device 2a shown in FIG. 4 is a stationary surveillance camera device 2a having a physical rotation function. The surveillance camera device 2a includes a base 21a, a case (housing) 22a, and a camera case 23a.

The base 21a is attached to a mounting surface such as a mounting base at the bottom.
The case 22a includes a pan motor 221a and a tilt motor 222a, which are stepping motors, and is configured to be rotatable with respect to the base 21a (can be rotated in the pan direction) by the pan motor 221a. In the second embodiment, as shown in FIG. 4B, the pan motor 221a is disposed below the gravitational direction in the case 22a in a state where the surveillance camera device 2a is attached to the attachment surface. It corresponds to the stepping motor 11. In addition, in the case 22a, the board 15 on which the driver 12, the thermistor 13 and the control unit 14 in the first embodiment are mounted is mounted.
The camera case 23a is configured to be rotatable (rotatable in the tilt direction) with respect to the case 22a by a tilt motor 222a.

  In this surveillance camera device 2a, the thermistor 13 measures the internal temperature of the case 22a. When the pan motor 221a is stationary and the internal temperature is equal to or lower than the use lower limit temperature, the driver control unit 143 generates heat to the coil (not shown) of the pan motor 221a with respect to the driver 12. Command to supply current. In response to this command, the driver 12 supplies the heat generation current to the coil supplying the stop current, and the coil generates heat. Here, since the pan motor 221a is mounted in the lower part of the case 22a, the heat generated from the coil of the pan motor 221a convects toward the upper part of the case 22a, and the entire case 22a can be uniformly heated.

Embodiment 3 FIG.
In the third embodiment, another application example of the heat generation structure 1 according to the first embodiment will be described.
FIG. 5 is a diagram showing a configuration example of a monitoring camera device 2b according to Embodiment 3 of the present invention.
The surveillance camera device 2b shown in FIG. 5 is a ceiling-mounted surveillance camera device 2b having a physical rotation function. The monitoring camera device 2b includes a base 21b, a case (housing) 22b, and a camera case 23b.

The upper surface of the base 21b is attached to an attachment surface such as a ceiling surface.
The case 22b includes a pan motor 221b and a tilt motor 222b, which are stepping motors, and is configured to be rotatable with respect to the base 21b (can be rotated in the pan direction) by the pan motor 221b. In the third embodiment, as shown in FIG. 5B, the tilt motor 222b is arranged below the gravitational direction in the case 22b in a state where the surveillance camera device 2b is mounted on the mounting surface. Corresponds to the stepping motor 11 in FIG. In addition, in the case 22b, the substrate 15 on which the driver 12, the thermistor 13 and the control unit 14 in the first embodiment are mounted is mounted.
The camera case 23b is configured to be rotatable (rotatable in the tilt direction) with respect to the case 22b by a tilt motor 222b.

  In the surveillance camera device 2b, the thermistor 13 measures the internal temperature of the case 22b. When the tilt motor 222b is stationary and the internal temperature is equal to or lower than the use lower limit temperature, the driver control unit 143 instructs the driver 12 to a coil (not shown) included in the tilt motor 222b. Command to supply current during heat generation. In response to this command, the driver 12 supplies the heat generation current to the coil supplying the stop current, and the coil generates heat. Here, since the tilt motor 222b is mounted on the lower part of the case 22b, the heat generated from the coil of the tilt motor 222b is convected toward the upper part of the case 22b, and the entire case 22b can be uniformly heated. it can.

Embodiment 4 FIG.
In the second embodiment, the stationary monitoring camera device 2a is used and the pan motor 221a generates heat.
On the other hand, for example, when the internal temperature of the case 22a becomes a temperature (for example, −20 ° C.) lower than the use limit lower limit temperature (for example, −10 ° C.), the internal temperature of the case 22a can be reduced only by the heat generated by the pan motor 221a alone. It cannot be raised to a usable temperature (for example, 0 ° C.). Therefore, in such a case, both the pan motor 221a and the tilt motor 222a may generate heat. Thereby, temperature can be raised more and it becomes possible to respond to a wider range of temperatures.

  In the above description, in the monitoring camera device 2a according to the second embodiment, the case where both the pan motor 221a and the tilt motor 222a generate heat has been described. However, the present invention is not limited to this, and in the monitoring camera device 2b according to Embodiment 3, both the pan motor 221b and the tilt motor 222b may generate heat.

Embodiment 5. FIG.
FIG. 6 is a partially transparent front view showing a configuration example of a monitoring camera apparatus 2a according to Embodiment 5 of the present invention. In the surveillance camera device 2a according to the fifth embodiment shown in FIG. 6, a guide 223 is added to the surveillance camera device 2a according to the second embodiment shown in FIG. Other configurations are the same, and the same reference numerals are given and description thereof is omitted.

  The guide 223 is a member that is disposed between the pan motor 221a and the substrate 15 and guides the heat generated by the coil of the pan motor 221a to the substrate 15 side. Thereby, even when the use environment temperature is lower than the lower limit temperature of use of the components mounted on the board 15, the board 15 can be warmed more efficiently than the entire case 22a. it can.

  In the above description, the case where the guide 223 is provided between the substrate 15 and the pan motor 221a that is a heating element is shown. However, the present invention is not limited to this, and a guide 223 may be provided between another substrate included in the case 22a and a pan motor 221a that is a heating element.

  Moreover, the case where the guide 223 was added to the monitoring camera apparatus 2a which concerns on Embodiment 2 shown in FIG. 4 above was shown. However, the present invention is not limited to this, and a guide 223 may be added to the monitoring camera devices 2a and 2b according to the third and fourth embodiments.

Embodiment 6 FIG.
FIG. 7 is a partially transparent front view showing a configuration example of a monitoring camera apparatus 2a according to Embodiment 6 of the present invention. In the surveillance camera device 2a according to the sixth embodiment shown in FIG. 7, a heat conducting plate 224 is added to the surveillance camera device 2a according to the second embodiment shown in FIG. Other configurations are the same, and the same reference numerals are given and description thereof is omitted.

  The heat conduction plate 224 is a member that connects the pan motor 221a and the component 225 provided in the housing, and is made of a member having high heat conductivity such as aluminum. FIG. 7 shows the case where the component 225 mounted on the substrate 15 is used as the component 225. As a result, even when the use environment temperature is lower than the lower limit temperature of use of the component 225, heat can be transferred from the pan motor 221a to the component 225 by heat conduction and heated. As a result, the components 225 can be warmed more efficiently than when heating the entire case 22a.

  In the above description, the case where the heat conduction plate 224 is added to the monitoring camera device 2a according to the second embodiment shown in FIG. However, the present invention is not limited to this, and the heat conduction plate 224 may be added to the monitoring camera devices 2a and 2b according to the third to fifth embodiments.

Embodiment 7 FIG.
FIG. 8 is a partially transparent front view showing a configuration example of a monitoring camera device 2a according to Embodiment 7 of the present invention. In the surveillance camera device 2a according to the sixth embodiment shown in FIG. 8, the outer surface of the pan motor 221a is colored black with respect to the surveillance camera device 2a according to the second embodiment shown in FIG. The other configuration examples are the same, and the same reference numerals are given and description thereof is omitted.

  The outer surface of the pan motor 221a in the seventh embodiment is colored black. Thus, by coloring the outer surface of the pan motor 221a, which is a heating element, in black, the amount of radiant heat is increased, and the internal temperature of the case 22a is higher than when the coloring is not performed.

  In the above description, the case where the outer surface of the pan motor 221a of the surveillance camera device 2a according to the second embodiment shown in FIG. However, the present invention is not limited thereto, and the outer surface of the stepping motor 11 (pan motors 221a, 221b, tilt motors 222a, 222b), which is a heating element of the monitoring camera devices 2a, 2b according to Embodiments 3 to 6, may be colored black. Good.

Embodiment 8 FIG.
FIG. 9 is a perspective view showing a configuration example of a pan motor 221a according to Embodiment 8 of the present invention. The pan motor 221a uses the pan motor 221a in the second embodiment.

  In the pan motor 221a according to the eighth embodiment, fin-shaped uneven portions 112 are provided on the outer surface. As described above, by providing the fin-shaped uneven portion 112 on the outer surface of the pan motor 221a that is a heating element, heat transfer to the internal air of the case 22a is improved, and the temperature rise value is higher than when the unevenness is not provided. Get higher.

  In the above description, the case where the uneven portion 112 is provided on the outer surface of the pan motor 221a of the surveillance camera device 2a according to the second embodiment has been described. However, the present invention is not limited to this, and an uneven portion 112 is provided on the outer surface of the stepping motor 11 (pan motors 221a, 221b, tilt motors 222a, 222b) which is a heating element of the monitoring camera devices 2a, 2b according to the third to seventh embodiments. Also good.

Finally, an example of the hardware configuration of the control unit 14 in the first to eighth embodiments will be described with reference to FIG.
The functions of the temperature acquisition unit 141, the temperature determination unit 142, and the driver control unit 143 in the control unit 14 are realized by the processing circuit 51. 10A, even if the processing circuit 51 is dedicated hardware, as shown in FIG. 10B, a CPU (Central Processing Unit, a central processing unit, a processing unit that executes a program stored in the memory 53 , An arithmetic device, a microprocessor, a microcomputer, a processor, or a DSP (Digital Signal Processor) 52.

  When the processing circuit 51 is dedicated hardware, the processing circuit 51 may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), or an FPGA (Field Programmable Gate). Array) or a combination thereof. The functions of the respective units of the temperature acquisition unit 141, the temperature determination unit 142, and the driver control unit 143 may be realized by the processing circuit 51, or the functions of the respective units may be collectively realized by the processing circuit 51.

  When the processing circuit 51 is the CPU 52, the functions of the temperature acquisition unit 141, the temperature determination unit 142, and the driver control unit 143 are realized by software, firmware, or a combination of software and firmware. Software and firmware are described as programs and stored in the memory 53. The processing circuit 51 implements the functions of each unit by reading and executing the program stored in the memory 53. That is, the control unit 14 includes a memory 53 for storing a program that, when executed by the processing circuit 51, for example, causes each step shown in FIG. 2 to be executed as a result. Further, it can be said that these programs cause the computer to execute the procedures and methods of the temperature acquisition unit 141, the temperature determination unit 142, and the driver control unit 143. Here, the memory 53 is, for example, a nonvolatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable ROM), or an EEPROM (Electrically EPROM). And a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, a DVD (Digital Versatile Disc), and the like.

  In addition, about each function of the temperature acquisition part 141, the temperature determination part 142, and the driver control part 143, a part may be implement | achieved by exclusive hardware and a part may be implement | achieved by software or firmware. For example, the function of the temperature acquisition unit 141 is realized by the processing circuit 51 as dedicated hardware, and the processing circuit 51 reads and executes the program stored in the memory 53 for the temperature determination unit 142 and the driver control unit 143. By doing so, the function can be realized.

  As described above, the processing circuit 51 can realize the above-described functions by hardware, software, firmware, or a combination thereof.

  In the present invention, within the scope of the invention, any combination of the embodiments, or any modification of any component in each embodiment, or omission of any component in each embodiment is possible. .

DESCRIPTION OF SYMBOLS 1 Heat generation structure, 2a, 2b Surveillance camera apparatus, 11 Stepping motor, 12 Driver, 13 Thermistor, 14 Control part, 15 Board | substrate, 21a, 21b Base, 22a, 22b Case (housing), 23a, 23b Camera case, 51 Process Circuit, 52 CPU, 53 Memory, 111 Coil, 112 Concavity and convexity part, 141 Temperature acquisition part, 142 Temperature determination part, 143 Driver control part, 221a, 221b Pan motor, 222a, 222b Tilt motor, 223 guide, 224 Heat conduction plate, 225 parts.

Claims (9)

A stepping motor provided in the housing and having a coil;
A driver for supplying current to the coil;
A thermistor for measuring the temperature in the housing;
A temperature acquisition unit for acquiring information indicating the temperature measured by the thermistor;
From the information indicating the temperature acquired by the temperature acquisition unit, a temperature determination unit that determines whether the temperature is a predetermined value or less,
When the temperature determination unit determines that the temperature is equal to or lower than a predetermined value, a driver control that instructs the driver to supply a current that causes the coil to generate heat to the coil that supplies a current during stoppage. A device with parts. After the temperature determination unit determines that the temperature is equal to or lower than a predetermined value, whether the temperature is equal to or higher than a second predetermined value higher than the predetermined value from the information indicating the temperature acquired by the temperature acquisition unit. Determine
The device according to claim 1, wherein the driver control unit stops the command to the driver when the temperature determination unit determines that the temperature is equal to or higher than a second predetermined value. The device according to claim 1, wherein the stepping motor is disposed below the gravitational direction in the housing. The apparatus according to any one of claims 1 to 3, wherein a plurality of the stepping motors are provided. A substrate provided in the housing;
5. The guide according to claim 1, further comprising a guide disposed between the stepping motor and the substrate and guiding heat generated by the coil of the stepping motor toward the substrate. The device according to any one of the above. Components provided in the housing;
The apparatus according to any one of claims 1 to 5, further comprising a heat conduction plate that connects the stepping motor and the component. The device according to any one of claims 1 to 6, wherein an outer surface of the stepping motor is colored black. The device according to any one of claims 1 to 7, wherein the stepping motor is provided with a fin-shaped uneven portion on an outer surface. A stepping motor having a coil;
A driver for supplying current to the coil;
A thermistor that measures the ambient temperature,
A temperature acquisition unit for acquiring information indicating the temperature measured by the thermistor;
From the information indicating the temperature acquired by the temperature acquisition unit, a temperature determination unit that determines whether the temperature is a predetermined value or less,
When the temperature determination unit determines that the temperature is equal to or lower than a predetermined value, a driver control that instructs the driver to supply a current that causes the coil to generate heat to the coil that supplies a current during stoppage. And a heat generating structure.

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