JP2011132772A - Electronic key - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control shortage of battery shortage in an electronic key. <P>SOLUTION: The electric power generated by an oscillating power generator 38 is stored in a capacitor 39. The stored electric power is used for communication etc. with a vehicle 2 as a second power source. The oscillating power generator 38 generates electric power by oscillation applied to the electronic key 3. Therefore, for example, when a user walks with the electronic key 3, electric power is generated by the oscillation applied to the electronic key 3, and the generated electric power can be stored. Furthermore, electric power is generated by shaking the electronic key 3 and the generated electric power can be stored, for example. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electronic key.

2. Description of the Related Art Conventionally, there is known an electronic key system that permits unlocking of a vehicle door, permission of starting an engine, and the like through wireless communication between the electronic key (portable device) and the vehicle side.
For example, in the electronic key system disclosed in Patent Document 1, the vehicle forms a communication area inside and outside the vehicle, and communicates with the electronic key existing in the communication area through transmission / reception of a radio signal including an ID code. When collation of the ID code included in the radio signal is established in the vehicle, for example, the vehicle door is switched to an unlockable state.

  In the electronic key system disclosed in Patent Document 2, a radio signal including an ID code is transmitted to the vehicle through an operation of a locking / unlocking switch provided on the electronic key. When the vehicle confirms the validity of the ID code included in the radio signal, the locked state of the vehicle door is switched.

  The electronic key in both the electronic key systems is provided with a battery as an operating power source. This electronic key performs various operations such as wireless signal transmission based on the power of the battery.

JP 2006-118886 A JP-A-7-54525

  By the way, when the electronic keys described in Patent Documents 1 and 2 operate on a battery, the battery may run out. When the battery runs out, the electronic key cannot communicate with the vehicle and the vehicle door cannot be unlocked. In this case, for example, a predetermined operation such as replacing the battery of the electronic key or using an emergency mechanical key built in the electronic key is necessary, which is troublesome for the user. Such a problem occurs not only in a vehicle electronic key but also in a residential electronic key, for example.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an electronic key capable of suppressing battery exhaustion.

Hereinafter, means for achieving the above-described object and its operation and effects will be described.
According to a first aspect of the present invention, there is provided an electronic key that performs wireless communication with a communication target, a battery that is a first power source of the electronic key, and a vibration power generation device that generates electric power by vibration applied to the electronic key. The gist of the invention is that the electric power generated by the vibration power generation apparatus is stored, and the stored electric power is provided as a second power source of the electronic key.

  According to this configuration, the electric power generated by the vibration power generator is stored in the power storage device, and the stored electric power is used for communication with the communication target as the second power source. Here, the vibration power generator generates power by vibration applied to the electronic key. Therefore, for example, when the user is walking with the electronic key walking, power can be generated by vibration applied to the electronic key, and the generated power can be stored. In addition, for example, power can be generated by shaking an electronic key, and the generated power can be stored.

  As described above, the power of the power storage device that is the second power source is used for communication or the like, so that the power consumption of the battery that is the first power source can be reduced, and the battery of the electronic key is dead. Can be suppressed.

  According to a second aspect of the present invention, in the electronic key according to the first aspect, the vibration power generation device vibrates when supplied with power, and voltage detection means for detecting the voltage of the battery and the voltage of the power storage device; When it is determined that the two voltages detected by the voltage detecting means are equal to or less than a threshold value set based on a voltage at which a remaining capacity of the battery and the power storage device is insufficient, the battery is connected to the vibration power generation device. And a control device that vibrates the vibration power generation device by supplying any power of the power storage device.

  According to this configuration, when the voltage of the battery and the power storage device is equal to or lower than the threshold value, the vibration power generation device is vibrated by supplying power to the vibration power generation device. Therefore, it is possible to make the user recognize the decrease in the remaining capacity of the battery and the power storage device through the vibration of the vibration power generation device by using the vibration power generation device as the power generation means. A user who recognizes a decrease in the remaining capacity can avoid the battery running out of the electronic key by shaking the electronic key to generate power or replacing the battery with a new one.

  According to a third aspect of the present invention, in the electronic key according to the second aspect, the vibration power generation device is movable relative to the coil by a coil around which an electric wire is wound and vibration applied to the electronic key. And a core made of a ferromagnetic material, and a power supply device that converts power from the power storage device and the battery and supplies it to the coil.

  According to this configuration, the vibration power generator includes the coil and the core. When it is desired to generate power, the electronic key is shaken, so that the core, which is a ferromagnetic material, moves inside the coil. Accordingly, the magnetic field inside the core changes, and an electromotive force is generated in the core by electromagnetic induction. This electromotive force becomes generated power.

  When it is desired to vibrate, the power converted through the power supply device is supplied to the vibration power generation device. Thereby, the polarity of a coil changes between N pole and S pole at the time of electricity supply. Therefore, the core is attracted to the coil or moved away by the magnetic force. Thereby, at the time of electricity supply, a core moves periodically within a coil and a vibration occurs. As described above, the vibration power generation device including the coil and the core can generate a large vibration compared to, for example, a piezoelectric element or the like. Therefore, the user can reliably recognize the decrease in the remaining capacity of the power storage device and the battery through vibration.

  According to the present invention, it is possible to suppress battery exhaustion in the electronic key.

The block diagram of the electronic key system in this embodiment. The perspective view of the vibration electric power generating apparatus in this embodiment. The perspective view of the electronic key which shows the attachment direction of the vibration electric power generating apparatus in this embodiment. (A)-(c) in this embodiment is sectional drawing which showed the vibration aspect of the core. The flowchart which shows the process sequence of the voltage drop notification program in this embodiment.

Hereinafter, an embodiment in which the present invention is embodied in an electronic key system will be described with reference to FIGS.
As shown in FIG. 1, in the vehicle electronic key system 1, unidirectional communication between the electronic key 3 possessed by the user and the vehicle 2 is possible.

<Electronic key>
The electronic key 3 includes an electronic key control unit 31, a transmission unit 33, an unlocking switch 34, a locking switch 35, a battery unit 36, a vibration power generation device 38, a power storage device 39, an inverter 41, and a cutoff circuit. 40 and a mechanical key 45.

  As shown in FIG. 1, the unlocking switch 34 and the locking switch 35 output an operation signal indicating that to the electronic key control unit 31 when operated. The electronic key control unit 31 includes a memory 31a that stores an ID code, a voltage drop notification program, and the like, and a timer 31b that measures a period T during which the electronic key 3 is left unattended. When receiving an operation signal indicating that the unlock switch 34 has been operated, the electronic key control unit 31 generates an unlock request signal including an ID code requesting the vehicle 2 to unlock the door. Then, the electronic key control unit 31 outputs this unlock request signal to the transmission unit 33. In addition, when receiving an operation signal indicating that the locking switch 35 has been operated, the electronic key control unit 31 generates a locking request signal including an ID code that requests the vehicle 2 to lock the door. Then, the electronic key control unit 31 outputs this locking request signal to the transmission unit 33.

  The transmission unit 33 modulates the unlock request signal or the lock request signal input from the electronic key control unit 31 into a radio wave of a predetermined frequency band. The predetermined frequency band is, for example, a UHF (Ultra High Frequency) band. The transmission unit 33 transmits the modulated unlocking request signal or locking request signal to the vehicle 2 side through the transmission antenna 33a.

  The battery unit 36 includes a converter that controls the discharge amount of the battery. The battery unit 36 supplies its own power to power supply targets such as the electronic key control unit 31 and the transmission unit 33 based on the command signal Sb from the electronic key control unit 31.

  The vibration power generator 38 can convert energy between vibration energy and electric energy. That is, the vibration power generator 38 generates power when vibration is applied to itself, and vibrates when power is supplied to itself. The vibration is applied to the vibration power generation device 38 not only when the user intentionally swings the electronic key 3 but also when the electronic key 3 is carried around while walking or the like. There is also a case to join. Note that the power generated by the vibration power generator 38 and the power supplied to the vibration power generator 38 are both AC power. The specific configuration of the vibration power generator 38 will be described in detail later.

  The power storage device 39 includes power storage means such as a capacitor and a secondary battery, and charge / discharge control means such as a converter. The power storage device 39 stores the power generated by the vibration power generation device 38. A cutoff circuit 40 and an inverter 41 are connected between the vibration power generation device 38 and the power storage device 39. Inverter 41 converts AC power from vibration power generation device 38 into DC power, and also converts DC power from power storage device 39 into AC power. As a result, the power generated by the vibration power generation device 38 can be stored in the power storage device 39, or the vibration power generation device 38 can be vibrated based on the power of the power storage device 39. The cutoff circuit 40 switches between the vibration power generation device 38 and the power storage device 39 between the conductive state and the non-conductive state based on the command signal Ss from the electronic key control unit 31.

  In addition, the power storage device 39 discharges to the vibration power generation device 38 side or stores the power from the vibration power generation device 38 based on the command signal Sc from the electronic key control unit 31. That is, the electronic key control unit 31 can control which power of the battery unit 36 and the power storage device 39 is used through the command signals Sc and Sb. In this example, the electronic key control unit 31 uses power stored in the power storage device 39 with priority. Here, unlike the battery unit 36, the power storage device 39 can store power as the vibration power generation device 38 generates power. By preferentially using the power of the power storage device 39, the power storage device 39 is fully charged, and the occurrence of a situation where power is not stored even though the electronic key 3 is vibrated to generate power is suppressed. Is done. Thereby, electric power can be utilized more efficiently and the battery running out of the electronic key 3 can be suppressed.

  The electronic key control unit 31 includes a voltage detection control circuit 37. The voltage detection control circuit 37 detects the voltage Vb of the battery unit 36 and the voltage Vc of the power storage device 39. Here, the voltages Vb and Vc have values corresponding to the remaining capacity of the battery unit 36 and the power storage device 39. In other words, the higher the voltages Vb and Vc, the greater the remaining capacity. Therefore, the voltage detection control circuit 37 can recognize the remaining capacity based on the voltages Vb and Vc detected by itself.

  Further, when the voltage detection control circuit 37 recognizes the voltage Vc of the power storage device 39 and determines that the power storage device 39 is in the full power storage state, the voltage detection control circuit 37 does not connect between the vibration power generation device 38 and the power storage device 39 through the cutoff circuit 40. Make it conductive. That is, when it is not in the full power storage state, the cutoff circuit 40 brings the vibration power generation device 38 and the power storage device 39 into a conductive state. Thereby, the excessive electrical storage of the electrical storage apparatus 39 is prevented.

  Furthermore, as shown in FIG. 1, the electronic key 3 houses a mechanical key 45 for emergency use. For example, in the electronic key 3, the mechanical key 45 is used when the remaining capacity of the battery unit 36 and the power storage device 39 decreases so that the lock request signal and the unlock request signal are difficult to transmit. When the mechanical key 45 is taken out from the electronic key 3, it is inserted into a key hole (not shown) of the vehicle 2 and manually rotated. Thereby, locking / unlocking of a vehicle door is attained.

<Vehicle>
As shown in FIG. 1, the vehicle 2 includes a receiving unit 21, an in-vehicle control unit 23, and a door lock device 27. The receiving unit 21 receives an unlock request signal or a lock request signal that is a radio wave of a predetermined frequency (UHF band) transmitted from the electronic key 3 through the receiving antenna 21a. The receiving unit 21 demodulates the unlock request signal or the lock request signal received by the receiving antenna 21 a to generate a received signal, and outputs the received signal to the in-vehicle control unit 23.

  The in-vehicle controller 23 includes a non-volatile memory 23a, and the memory 23a stores the same ID code as the ID code of the electronic key 3 suitable for the vehicle 2. When the in-vehicle control unit 23 recognizes that the reception signal input from the reception unit 21 is an unlock request signal, the in-vehicle control unit 23 compares the ID code included in the unlock request signal with the ID code stored in the memory 23a. . The in-vehicle controller 23 unlocks the vehicle door through the door lock device 27 when the ID code verification is established. Similarly to the unlocking, the in-vehicle control unit 23 locks the vehicle door through the door lock device 27 when the ID code included in the locking request signal and the ID code stored in the memory 23a are verified. To do.

Next, a specific configuration of the vibration power generator 38 will be described with reference to FIGS. 2 to 4A to 4C.
As shown in FIG. 2, the vibration power generator 38 includes a coil 50 around which an electric wire is wound, and a core 51 made of a rod-like magnet (ferromagnetic material) inserted through the coil 50. The core 51 has N and S poles at both ends, and forms a magnetic field around itself. Accordingly, a magnetic field is formed inside the coil 50 by the core 51. The core 51 is provided so as to be movable relative to the coil 50 along the axial direction inside the coil 50 to be fixed. The movement of the core 51 in the axial direction is restricted by restriction walls 52a and 52b provided on both sides of the coil 50 in the axial direction, as shown in FIG. This prevents the core 51 from coming out of the coil 50.

  When the vibration is applied to the electronic key 3, the core 51 performs a piston motion (reciprocating linear motion) inside the coil 50. Thereby, the magnetic field inside the coil 50 changes, and an electromotive force is generated between both ends of the coil 50 by electromagnetic induction. The electromotive force becomes generated power and is stored in the power storage device 39. Where there is a fixed relationship between the change in the magnetic field and the direction of the current, the direction of the current generated in the coil 50 is also reversed each time the displacement direction of the core 51 is reversed. Therefore, the generated power (electromotive force) is AC power.

  Regardless of the direction in which the electronic key 3 is swung, the core 51 and the coil 50 are installed at a position where power generation is possible. Specifically, as shown in FIG. 3, it is assumed that the electronic key 3 is located along the X axis, the Y axis, and the Z axis that are orthogonal to each other. As shown in the upper left of FIG. 3, if the point where the axes intersect is a coordinate (0, 0, 0), the position when 1 is taken in the direction of each axis with this origin as a reference is the coordinate (1, 1, 1 ). The coil 50 and the core 51 are installed so that the direction along the line connecting the coordinates (0, 0, 0) and the coordinates (1, 1, 1) is the axial direction of the coil 50 and the core 51. By installing the coil 50 and the core 51 in this direction, even if the electronic key 3 is swung in any direction of the X axis, the Y axis, and the Z axis, an external force is applied along the core axis direction to cause the coil 50 to move. The core 51 moves inside. Therefore, power generation is possible.

  On the contrary, when the alternating current from the inverter 41 is supplied to the coil 50, the core 51 performs a piston motion inside the coil 50. The electronic key 3 can be vibrated by this piston movement.

  Specifically, when an alternating current is passed through the coil 50, the coil 50 becomes a magnet having N and S poles. Here, the polarity which the coil 50 forms as a magnet changes according to the direction of an electric current. Further, the strength of the magnetic field formed by the coil 50 changes according to the magnitude of the current supplied to the coil 50. Therefore, when an alternating current is supplied to the coil 50, the strength and polarity of the magnetic field formed by the coil 50 change with time.

  For example, as shown in FIG. 4 (a), when the N pole side end of the core 51 is in contact with the regulating wall 52a, the left side of the coil 50 is the S pole and the right side is the N pole. The N pole of the core 51 and the S pole of the coil 50, the S pole of the core 51 and the N pole of the coil 50 are attracted to each other, and the core 51 moves to the right.

  Next, as shown in FIG. 4B, when the core 51 moves to the right inside the coil 50, the polarity of the coil 50 changes. The left side of the coil 50 is an N pole, and the right side is an S pole. As a result, the N pole of the core 51 and the N pole of the coil 50, the S pole of the core 51 and the S pole of the coil 50 repel each other, and the core 51 further moves to the right as shown in FIG. And abuts against the regulating wall 52b.

  When the core 51 is in contact with the regulation wall 52b and the left side of the coil 50 is the S pole and the right side is the N pole, the N pole of the core 51, the S pole of the coil 50, and the S pole of the core 51 And the N pole of the coil 50 attract each other, and the core 51 moves to the left. As described above, the magnetic pole of the coil 50 changes, so that the core 51 performs a piston motion in the coil 50. The electronic key 3 vibrates with this piston movement. This vibration is recognized by the user through touch and hearing. In this way, by configuring the vibration power generation device 38 with the coil 50 and the core 51, the user can vibrate the electronic key 3 greatly with ease of recognition. Specifically, since the core 51 moves in the coil 50, for example, a large vibration can be obtained as compared with the vibration generated by the piezoelectric element.

Next, the processing procedure of the voltage drop notification program executed by the electronic key control unit 31 will be described with reference to the flowchart of FIG.
First, the presence / absence of a switch operation is determined through the presence / absence of an operation signal from the unlocking switch 34 or the locking switch 35 (S101). When it is determined that the unlock switch 34 or the lock switch 35 is operated (YES in S101), the measurement of the period T is started through the timer 31b (S102). In subsequent steps S103 to S106, the remaining capacities of the power storage device 39 and the battery unit 36 are checked, and when these remaining capacities are small, the fact is notified to the user through the vibration of the electronic key 3. Specifically, the voltages Vb and Vc are recognized through the voltage detection control circuit 37 (S103). Then, it is determined whether or not the voltage Vb of the battery unit 36 is equal to or lower than the threshold value Vth1 (S104). The threshold value Vth1 is the voltage Vb when the remaining capacity of the battery unit 36 decreases while maintaining the power to vibrate the vibration power generation device 38 and the power that can transmit the lock request signal and the unlock request signal only several times. Is set as a reference. If voltage Vb of battery unit 36 exceeds threshold value Vth1 (NO in S104), the remaining capacity of battery unit 36 is sufficient and the processing of the program is terminated.

  When voltage Vb of battery unit 36 is equal to or lower than threshold value Vth1 (YES in S104), it is determined whether or not voltage Vc of power storage device 39 is equal to or lower than threshold value Vth2 (S105). The threshold value Vth2 is the voltage Vc when the remaining capacity of the power storage device 39 decreases while maintaining the power for vibrating the vibration power generation device 38 and the power for transmitting the lock request signal and the unlock request signal only several times. Is set as a reference. That is, both threshold values Vth1 and Vth2 are set based on voltages Vb and Vc when there is a possibility that it will be difficult to secure the power required for the operation related to request signal transmission in the near future. When voltage Vc of power storage device 39 exceeds threshold value Vth2 (NO in S105), it is determined that the remaining capacity of power storage device 39 is sufficient, and the processing of the program ends.

  When voltage Vc of power storage device 39 is equal to or lower than threshold value Vth2 (YES in S105), vibration power generation device 38 is vibrated for a predetermined time (S106). Specifically, the electric power of the power storage device 39 or the battery unit 36 is supplied to the vibration power generation device 38 through the command signals Sc and Sb. Also in this case, the power of the power storage device 39 is used with priority. Program processing is terminated.

  As described above, when the unlocking switch 34 or the locking switch 35 is operated by the user when the remaining capacity of the battery unit 36 and the power storage device 39 is small, the user is made aware through the vibration of the electronic key 3 that the remaining capacity is small. be able to.

  On the other hand, when it is determined that there is no operation of the unlocking switch 34 or the locking switch 35 (NO in S101), it is determined whether or not the period T has passed a certain period T1 from the measurement start in step S102 (S107). . If the period T has not passed the predetermined period T1 (NO in S107), the processing of the program is terminated. Then, in the next program, when it is determined that the unlock switch 34 or the lock switch 35 is not operated (NO in S101), it is determined again whether or not the predetermined period T1 has passed (S107). When the period T has passed the predetermined period T1 (YES in S107), the period T measured through the timer 31b is reset (S108). Then, as described above, the remaining capacity of the power storage device 39 and the battery unit 36 is checked by the processing of steps S103 to S105, and when these remaining capacities are small, the remaining capacity is obtained through the vibration of the electronic key 3 by the processing of step S106. The user is notified that there is little. As described above, whether or not the battery has run out is checked when the unlocking switch 34 or the locking switch 35 is operated and when the predetermined period T1 has elapsed. Here, the fixed period T1 can be arbitrarily set.

  If the remaining capacities of the power storage device 39 and the battery unit 36 are not improved after that, when the switch operation is performed in a situation where the voltages Vb and Vc are equal to or lower than the threshold values Vth1 and Vth2, or for a certain period of time. When T1 has elapsed, the user is notified that the remaining capacity is low due to vibration even when the next program is executed.

  Further, when the electronic key 3 is not operated for a long period of time, for example, even when the electronic key 3 is stored at home, the remaining capacity of the battery unit 36 and the power storage device 39 is checked for a certain period, and the battery unit 36 and When the remaining capacity of the power storage device 39 is small, the fact is notified to the user through the vibration of the electronic key 3. The user can recognize not only the vibration by tactile sense but also the vibration sound generated by the vibration by hearing.

  The user can know the decrease in the remaining capacity of the battery unit 36 and the power storage device 39 through the vibration of the electronic key 3. For example, the user can store power by shaking the electronic key 3 or replace the battery of the battery unit 36. Can be performed in advance. Thereby, the remaining capacity of the battery unit 36 and the power storage device 39 of the electronic key 3 is lost, and a situation in which the vehicle door cannot be unlocked through wireless communication can be suppressed.

  The vibration power generator 38 has both a power generation function and a notification function. For this reason, it is possible to suppress the battery running out of the electronic key 3 from both sides of power generation and notification while suppressing the enlargement of the electronic key 3.

As described above, according to the embodiment described above, the following effects can be obtained.
(1) The electric power generated by the vibration power generation device 38 is stored in the power storage device 39, and the stored electric power is used for communication with the vehicle 2 and the like. Here, the vibration power generator 38 generates power by vibration applied to the electronic key 3. Therefore, for example, when the user is walking with the electronic key 3 walking, the power is generated by vibration applied to the electronic key 3, and the generated power can be stored. Further, for example, the user can intentionally shake the electronic key 3 to generate power and store the generated power.

  As described above, the power of the power storage device 39 as the second power source is used for communication or the like, so that the power consumption of the battery unit 36 as the first power source can be reduced. Can be prevented from running out of battery.

  (2) When the voltages Vb and Vc of the battery unit 36 and the power storage device 39 become equal to or lower than the threshold values Vth1 and Vth2, power is supplied to the vibration power generation device 38 to vibrate the vibration power generation device 38. Therefore, by using the vibration power generation device 38 as the power generation means, the user can recognize the decrease in the remaining capacity of the battery unit 36 and the power storage device 39 through the vibration of the vibration power generation device 38. The user who has recognized the decrease in the remaining capacity can avoid the battery running out of the electronic key 3 by shaking the electronic key 3 to generate power or replacing the battery with a new one.

  (3) The vibration power generator 38 includes a coil 50 and a core 51. When it is desired to generate electric power, the electronic key 3 is shaken, so that the core 51 that is a ferromagnetic body moves inside the coil 50. Therefore, the magnetic field inside the core 51 changes, and an electromotive force is generated in the core 51 by electromagnetic induction. This electromotive force becomes generated power.

  When it is desired to vibrate, the AC power converted through the inverter 41 is supplied to the vibration power generator 38. Thereby, the polarity of the coil 50 changes between the N pole and the S pole during energization. Therefore, the core 51 is attracted to the coil 50 or moved away by the magnetic force. Thereby, at the time of electricity supply, the core 51 moves periodically within the coil 50, and a vibration generate | occur | produces. As described above, the vibration power generation device 38 including the coil 50 and the core 51 can generate a larger vibration than, for example, a piezoelectric element or the like. Therefore, the user can reliably recognize the decrease in the remaining capacity of the power storage device 39 and the battery unit 36 through vibration.

In addition, the said embodiment can be implemented with the following forms which changed this suitably.
In the above embodiment, the core 51 vibrates with respect to the coil 50 to be fixed. However, the coil 51 may be vibrated by fixing the core 51.

  In the above embodiment, the vibration power generator 38 is configured by the coil 50 and the core 51. However, the vibration power generation device 38 is not limited to the coil 50 and the core 51 as long as energy conversion can be performed in both directions between vibration energy and electric energy. For example, the vibration power generation device 38 may have a configuration using a piezoelectric element.

  In the above embodiment, an inverter that is a DC / AC converter is used as the power supply device. However, the power supply device is not limited to an inverter. For example, an F / V (frequency / voltage) converter that is a DC voltage converter is used. Also good.

  In the above embodiment, as shown in FIG. 5, when the unlock switch 34 or the lock switch 35 is operated (YES in S102), the remaining capacity of the battery unit 36 and the power storage device 39 is checked ( S104-). However, the processing procedure of step S102 may be omitted. In this case, the remaining capacity is checked every fixed period T1.

  In the above embodiment, the user is notified that the remaining capacity of the battery unit 36 and the power storage device 39 is small through vibration of the electronic key 3. However, the notification means is not limited to this, and for example, a lighting means such as a light emitting diode may be provided, and the user may be notified through the lighting of the lighting means. In this case, the vibration power generator 38 is used only for power generation. Further, the electronic key 3 may be vibrated and lit to notify the user.

  In the above embodiment, there is an electronic key system 1 called a so-called wireless key system in which a lock request signal and an unlock request signal are transmitted from the electronic key 3 to the vehicle 2 so that the vehicle door can be locked and unlocked. It was adopted. However, since the electronic key 3 returns a response signal in response to a request signal transmitted from the vehicle 2 to the vehicle periphery, the user can lock and unlock the vehicle door without operating the electronic key 3. A so-called key operation free system may be adopted. In this system, since the operation is free, the unlocking switch 34 and the locking switch 35 are omitted. Further, the vehicle 2 is newly provided with a transmission unit that transmits a request signal, and the electronic key 3 is newly provided with a reception unit that receives the request signal. In this system, it is determined whether or not the electronic key 3 has received a request signal from the vehicle 2 in step S102 shown in the flowchart of FIG. If it is determined that the request signal has been received, the process proceeds to step S104. If it is determined that the request signal has not been received, the process proceeds to step S103. Also in this system, the battery of the electronic key 3 is prevented from running out as in the above embodiment. A system combining a key operation free system and a wireless key system may be employed.

In the above embodiment, the electronic key 3 is applied to the vehicle electronic key system 1, but the present invention is not limited to the vehicle, and may be applied to, for example, a residential electronic key system.
Next, the technical idea that can be grasped from the embodiment will be described together with the effects.

  (A) In the electronic key according to claim 2, the communication target is a vehicle, and a lock / unlock switch that transmits a radio signal requesting the lock / unlock of the door lock of the vehicle by a switch operation is provided. And an electronic key for determining whether or not the two voltages detected by the voltage detecting means are equal to or lower than a threshold when the control device recognizes that the locking / unlocking switch has been operated.

  According to this configuration, the voltage of the power storage device and the battery, that is, the remaining capacity of the power storage device and the battery is determined when the locking / unlocking switch is operated, and if the remaining capacity is insufficient, the electronic key is vibrated. In this way, by vibrating the electronic key during the operation of the locking / unlocking switch, the user can reliably recognize the decrease in the remaining capacity.

  (B) In the electronic key according to claim 2 or (a), the communication target is a vehicle, and a radio signal is transmitted to request locking / unlocking of the door lock of the vehicle by a switch operation. Whether the two voltages detected by the voltage detecting means are equal to or lower than a threshold value when the control device determines that the locking / unlocking switch has not been operated for a certain period of time. Electronic key to determine whether or not.

  According to the configuration, when the operation of the locking / unlocking switch is not performed for a certain period, the remaining capacity of the power storage device and the battery is determined, and when the remaining capacity is insufficient, the electronic key is vibrated. Thereby, for example, even when the electronic key is stowed in a storage space that cannot be visually recognized from the outside, the user can recognize the presence of the electronic key with a small remaining capacity by vibrating the electronic key.

(C) The electronic key according to any one of claims 1 to 3, and (b), wherein the electric power stored in the power storage device is used in preference to the battery.
According to this configuration, power stored in the power storage device with priority over the battery is used. Therefore, for example, the occurrence of a situation in which the power storage device is not stored even though the power storage device is in a fully stored state and vibrations that can generate power are added to the electronic key is suppressed. Thereby, electric power can be utilized more efficiently and the battery running out of the electronic key can be suppressed.

  (D) In the electronic key according to any one of claims 2 and 3 or the above-mentioned items (a) to (c), the electronic key includes a cut-off circuit that cuts off power supply from the vibration power generation device to the power storage device, When the control device determines that the voltage of the power storage device is sufficient based on the detection result of the voltage detection means, the electronic key that cuts off the power supply from the vibration power generation device to the power storage device through the cutoff circuit .

  According to this configuration, when it is determined that the voltage of the power storage device is sufficient, for example, when the power storage device is fully charged, the power supply from the vibration power generation device to the power storage device is cut off through the cutoff circuit. As a result, overpower storage in the power storage device can be prevented.

  DESCRIPTION OF SYMBOLS 1 ... Electronic key system, 2 ... Vehicle (communication object), 3 ... Electronic key, 31 ... Electronic key control part (control apparatus), 34 ... Unlocking switch, 35 ... Locking switch, 36 ... Battery unit, 37 ... Voltage detection Control circuit (voltage detection means, control device), 38 ... vibration power generation device, 39 ... power storage device, 40 ... cut-off circuit, 41 ... inverter (power supply device), 50 ... coil, 51 ... core.

Claims (3)

In the electronic key for wireless communication with the communication target,
A battery which is a first power source of the electronic key;
A vibration power generation device that generates power by vibration applied to the electronic key;
An electronic key comprising: a power storage device that stores electric power generated by the vibration power generation device, and the stored electric power is a second power source of the electronic key. The electronic key according to claim 1, wherein
The vibration power generation device vibrates when supplied with power,
Voltage detection means for detecting the voltage of the battery and the voltage of the power storage device;
When it is determined that the two voltages detected by the voltage detecting means are equal to or less than a threshold value set based on a voltage at which a remaining capacity of the battery and the power storage device is insufficient, the battery is connected to the vibration power generation device. And a control device that vibrates the vibration power generation device by supplying any power of the power storage device. The electronic key according to claim 2,
The vibration power generation device includes: a coil formed by winding an electric wire; and a core made of a ferromagnetic material that is inserted so as to be relatively movable with respect to the coil by vibration applied to the electronic key. And an electronic key comprising a power supply device for supplying power from the battery to the coil.

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