Vehicle power discharge device

Abstract

This invention provides a vehicle power supply discharge device that can rapidly discharge the backup power supply. [Solution] The vehicle power discharge device 100 comprises a backup power supply 20 as a backup for the on-board battery 10 mounted on the vehicle V, a motor 12 that operates using power supplied from the on-board battery 10 or the backup power supply 20, and a control unit 40 that can detect the voltage of the backup power supply 20 and controls the operation of the motor 12. The control unit 40 performs a discharge process that operates the motor 12 until the detected voltage, which is the detected voltage of the backup power supply 20, falls below a predetermined voltage.

Description

Technical Field

[0001] The present invention relates to a vehicle power supply discharge device.

Background Art

[0002] Patent Document 1 discloses a door lock system including a door lock motor for locking and unlocking a vehicle door, a battery installed in a vehicle body for storing electric power for driving the door lock motor, and a capacitor installed in the door and capable of storing electric power for driving the door lock motor as an auxiliary power source. The door lock system is configured to drive the door lock motor by the electric power stored in the backup power source on the door side when the electric power from the battery on the vehicle body side is interrupted.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For example, when the auxiliary power source (hereinafter referred to as the backup power source) is composed of an electric double layer capacitor, the electric double layer capacitor is more likely to deteriorate as it approaches a fully charged state where electric power is stored up to the upper limit of the capacitance. Therefore, a backup power source that can quickly discharge when there is no need to store electric power is desired.

[0005] The present invention has been made in view of the above problems, and an object thereof is to provide a vehicle power supply discharge device capable of quickly discharging a backup power source.

Means for Solving the Problems

[0006] As a means to solve the above problems, the present invention provides a vehicle power discharge device comprising: a backup power supply as a backup for an on-board battery mounted in a vehicle; a motor that operates using power supplied from the on-board battery or the backup power supply; and a control unit that can detect the voltage of the backup power supply and controls the operation of the motor, wherein the control unit performs a discharge process to operate the motor with power supplied from the backup power supply until the detected voltage, which is the detected voltage of the backup power supply, falls below a predetermined voltage.

[0007] According to the above configuration, the motor is operated until the detected voltage detected by the control unit falls below a predetermined voltage, thereby consuming the power stored in the backup power supply. Therefore, the backup power supply can be discharged more quickly compared to when it is discharged through a resistive element.

[0008] The device further comprises a fork rotatable between a fully latched position for holding a striker and an open position for releasing the striker, and a claw rotatable between a locked position for locking the fork in the fully latched position and an unlocked position for releasing the fork, wherein the control unit may rotate the claw by operating the motor during the discharge process.

[0009] With the above configuration, the power stored in the backup power supply can be consumed by operating the motor that rotates the claw, thus allowing the backup power supply to be discharged quickly.

[0010] The device further comprises a rotating member that is rotatable to a first orientation and a second orientation, and which rotates the claw from the locked position to the unlocked position by rotating to the first orientation, and the control unit may rotate the rotating member to the second orientation by operating the motor during the discharge process.

[0011] According to the above configuration, the rotating member rotates in a second direction opposite to the first direction that causes the claw that locks the fork to be in the unlocked position. This prevents the claw from unintentionally being in the unlocked position and releasing the lock on the fork. As a result, the backup power supply can be safely discharged.

[0012] The system may further include a restricting member that restricts the rotation of the rotating member in the second direction.

[0013] According to the above configuration, the rotating member can rotate in a second direction, avoiding collision of the rotating member with other components arranged around it. Therefore, the backup power supply can be safely discharged.

[0014] The control unit may perform the discharge process when the ignition switch is switched from on to off.

[0015] A backup power supply is provided as a backup to the vehicle's battery, for example, in case power is not supplied from the vehicle's battery due to an accident while driving. Therefore, when the ignition switch is switched from on to off, the backup power supply does not need to store power, and as in the configuration described above, by performing a discharge process at the timing when the ignition switch is switched from on to off, the backup power supply can be discharged at the appropriate time.

[0016] The backup power supply may be composed of an electric double-layer capacitor.

[0017] Electric double-layer capacitors tend to degrade more easily when they are close to a fully charged state, where power is stored up to the upper limit of their capacity. However, with the above configuration, the degradation of the backup power supply can be suppressed. [Effects of the Invention]

[0018] According to the vehicle power supply discharge device of the present invention, the backup power supply can be discharged quickly.

Brief Description of the Drawings

[0019] [Figure 1] Block diagram showing a vehicle power discharge device according to an embodiment. [Figure 2] Diagram showing a rotating member in a first posture according to an embodiment. [Figure 3] Diagram showing a rotating member in a second posture according to an embodiment. [Figure 4] Flowchart showing a second discharge process according to an embodiment.

Embodiments of the Invention

[0020] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding elements are denoted by the same reference numerals throughout, and redundant detailed descriptions are omitted.

[0021] The vehicle power discharge device 100 shown in FIG. 1 (hereinafter referred to as the "discharge device 100") is mounted on a vehicle V. The discharge device 100 includes a power supply device 1, a signal output unit 5, and a door latch device 6.

[0022] (Power Supply Device) The power supply device 1 includes an in-vehicle battery 10, a motor drive unit 11, a motor 12, a pre-driver 13, and a current detection unit 14. The power supply device 1 also includes a backup power supply 20, a charging unit 21, a discharge unit 22, a switching unit 23, an in-vehicle battery voltage acquisition unit 24, a voltage stabilization unit 25, and a control unit 40.

[0023] Furthermore, the power supply device 1 has a main power supply line L1, a sub-power supply line L2, a charging line L3, a main control power supply line L4, a sub-control power supply line L5, a main drive line L6, a sub-drive line L7, and a ground line GL. The current detection unit 14, the pre-driver 13, the backup power supply 20, the discharge unit 22, and the control unit 40 are grounded via the ground line GL.

[0024] (In-vehicle Battery) The on-board battery 10 is mounted on the vehicle V (vehicle body). The on-board battery 10 is, for example, a lead-acid battery and is capable of storing electricity. The on-board battery 10 can also supply power to prime movers and other components mounted on the vehicle V other than the motor 12. The nominal voltage of the on-board battery 10 is 12V, but the output voltage fluctuates within a range of, for example, 9V to 16V.

[0025] The onboard battery 10 is connected to the motor drive unit 11 via the switching unit 23 by the main power supply line L1, and supplies power to the motor drive unit 11.

[0026] (Motor drive unit) The motor drive unit 11 supplies power to the motor 12. Power is supplied to the motor 12 via the motor drive unit 11 from the onboard battery 10 or backup power supply 20. When power is supplied and the motor 12 operates, the door latch device 6 is driven. This makes it possible to open and close the doors of the vehicle V.

[0027] (motor) Motor 12 is a motor capable of forward and reverse rotation, and is, for example, a DC motor. Motor 12 operates within a predetermined voltage range (hereinafter referred to as the operating voltage range). In this embodiment, motor 12 is a so-called low-voltage motor, and the operating voltage range of motor 12 is lower than the minimum output voltage of the onboard battery 10. For example, the minimum output voltage of the onboard battery 10 is 9V, and the operating voltage range of motor 12 is 3V to 8V.

[0028] (Pre-driver) The pre-driver 13 adjusts the voltage supplied from the vehicle battery 10 to the motor 12 via the motor drive unit 11 to a voltage within the operating voltage range (for example, by PWM control). By adjusting the voltage supplied to the motor 12 by the pre-driver 13, the motor 12 can be operated stably even if the vehicle battery 10 is selected as the power source (power supply) for the motor 12 and a low-voltage motor is used as the motor 12. The operation of the pre-driver 13 is controlled by the control unit 40.

[0029] (Current detection unit) The current detection unit 14 detects the current flowing through the motor 12 and outputs information (signal) indicating the detected current value. When the current value output from the current detection unit 14 exceeds a predetermined threshold, the control unit 40 determines that an overcurrent has occurred in the motor 12 and controls the switching unit 23, which will be described in detail later, to disconnect the connection between the onboard battery 10 and the backup power supply 20 and the motor drive unit 11, thereby cutting off the current flowing through the motor 12.

[0030] (Backup power supply) The backup power supply 20 is a backup power source for the onboard battery 10. The backup power supply 20 is provided in case the power from the onboard battery 10 is cut off due to damage to the vehicle V caused by an accident or the like. The backup power supply 20 is located, for example, in a door (not shown).

[0031] The backup power supply 20 is composed of capacitors. In this embodiment, the backup power supply 20 is configured by connecting two capacitors 20a and 20b in series. Each capacitor 20a and 20b is an electric double-layer capacitor.

[0032] The output voltage of each capacitor 20a and 20b is, for example, 2.5V to 3V, preferably 3V, and the voltage of the backup power supply 20 when it is fully charged (hereinafter referred to as fully charged) is 5V to 6V, preferably 6V. As the backup power supply 20 discharges, the stored power (charge) decreases and the voltage drops.

[0033] The backup power supply 20 is connected to the vehicle battery 10 via a charging cable L3 through a charging unit 21. The backup power supply 20 is charged by the operation of the charging unit 21 being controlled by the control unit 40.

[0034] (Charge part) The charging unit 21 supplies power from the vehicle battery 10 to the backup power supply 20. This charges the backup power supply 20. Specifically, the charging unit 21 includes, for example, an on / off switch. When the on / off switch is closed, power is supplied from the vehicle battery 10 to the backup power supply 20. As a result, the backup power supply 20 is charged. On the other hand, when the on / off switch is open, the supply of power from the vehicle battery 10 to the backup power supply 20 is stopped, and the backup power supply 20 becomes dischargeable. The operation of the charging unit 21 is controlled by the control unit 40.

[0035] (discharge part) The discharge unit 22 adjusts the voltages of the two capacitors 20a and 20b of the backup power supply 20 to be equal. The discharge unit 22 is realized by two discharge control lines 22a and 22b, for example, an equalization circuit or cell balancing circuit that includes elements such as resistors and switches. The discharge control lines 22a and 22b connect the control unit 40 and the backup power supply 20.

[0036] The control unit 40 can detect the potential (voltage) of each discharge control line 22a, 22b. Based on the potentials of the discharge control lines 22a, 22b, the control unit 40 controls the discharge unit 22 to discharge the backup power supply 20. Hereinafter, the process of discharging the backup power supply 20 by the discharge unit 22 will be referred to as the first discharge process. The potential (voltage) detected by the control unit 40 will be referred to as the detected voltage.

[0037] Furthermore, the backup power supply 20 is connected to the motor drive unit 11 (motor 12) via the switching unit 23 through the main power supply line L1 and the sub-power supply line L2. The backup power supply 20 supplies power to the motor 12 in place of the onboard battery 10 by controlling the operation of the switching unit 23.

[0038] (Switching section) The switching unit 23 switches the power supply source for the motor drive unit 11 (motor 12) between the onboard battery 10 and the backup power supply 20. The switching unit 23 has a main switch element 23a and a sub-switch element 23b. The operation of the switching unit 23, that is, the opening and closing of the main switch element 23a and the sub-switch element 23b, is controlled by the control unit 40.

[0039] The main switch element 23a is connected to the main power supply line L1, which connects the onboard battery 10 and the motor drive unit 11. The sub-switch element 23b is connected to the sub-power supply line L2, which connects the backup power supply 20 and the motor drive unit 11. In other words, the motor drive unit 11 is connected to the onboard battery 10 via the main power supply line L1 through the main switch element 23a, and to the backup power supply 20 via the sub-power supply line L2 through the sub-switch element 23b. The sub-power supply line L2 is connected to the main power supply line L1 between the main switch element 23a and the motor drive unit 11.

[0040] When the main switch element 23a is closed and the sub-switch element 23b is open, power from the vehicle battery 10 is supplied to the motor drive unit 11. On the other hand, when the main switch element 23a is open and the sub-switch element 23b is closed, power from the backup power supply 20 is supplied to the motor drive unit 11.

[0041] (Vehicle battery voltage acquisition unit) The vehicle battery voltage acquisition unit 24 acquires the output voltage of the vehicle battery 10. The vehicle battery voltage acquisition unit 24 is connected, for example, to the main power supply line L1 and outputs information (signal) indicating the output voltage of the vehicle battery 10.

[0042] (Voltage stabilization unit) The voltage stabilization unit 25 is connected to the main control power line L4, which connects the onboard battery 10 and the control unit 40. The voltage stabilization unit 25 is also connected to the sub-control power line L5, which connects the backup power supply 20 and the control unit 40. Furthermore, the voltage stabilization unit 25 is also connected to the pre-driver 13 via the sub-drive line L7 and the main drive line L6.

[0043] The voltage stabilization unit 25 adjusts (boosts) the output voltage of the onboard battery 10 or backup power supply 20 to a voltage (e.g., 5V) that allows the pre-driver 13 and control unit 40 to operate stably. In other words, the onboard battery 10 or backup power supply 20 supplies power to the control unit 40 and pre-driver 13 via the voltage stabilization unit 25.

[0044] The main control power line L4 is connected to the charging line L3 on the vehicle battery 10 side of the charging unit 21. Similarly, the main drive line L6 is connected to the charging line L3 on the vehicle battery 10 side of the charging unit 21. The sub-control power line L5 is connected to the sub-switch element 23b on the backup power supply 20 side of the sub-power supply line L2. The sub-drive line L7 branches off from the main control power line L4 on the control unit 40 side of the voltage stabilization unit 25 and is connected to the main drive line L6.

[0045] Furthermore, the power supply unit 1 further includes a first diode D1 and a second diode D2. The first diode D1 is connected to the auxiliary drive line L7 and allows current to flow only in the direction from the backup power supply 20 to the pre-driver 13. The second diode D2 is connected to the main drive line L6 and, on the side of the vehicle battery 10 than the connection point with the auxiliary drive line L7, allows current to flow only in the direction from the vehicle battery 10 to the pre-driver 13.

[0046] (Control Unit) The control unit 40 controls the operation of each part of the power supply unit 1, such as the motor drive unit 11. The control unit 40 includes, for example, a CPU (Central Processing Unit) or MPU (Micro Processing Unit) that works in cooperation with software to realize predetermined functions. The control unit 40 may be composed of hardware circuits such as dedicated electronic circuits or reconfigurable electronic circuits designed to realize predetermined functions, or it may be composed of various semiconductor integrated circuits. Examples of various semiconductor integrated circuits include, in addition to CPUs and MPUs, microcomputers, DSPs (Digital Signal Processors), FPGAs (Field Programmable Gate Arrays), and ASICs (Application Specific Integrated Circuits). The control unit 40 may also include storage devices such as RAM (Random Access Memory), ROM (Read Only Memory), and EEPROM (Electrically Erasable Programmable Read-Only Memory). The storage device temporarily or permanently stores programs for executing processes (first discharge process and second discharge process) for discharging the backup power supply 20, and information used to execute these programs. Furthermore, when power is stored in the backup power supply 20, the control unit 40 is supplied with power from the backup power supply 20.

[0047] (Signal output section) The signal output unit 5 includes a release command output unit 51, a latch status signal output unit 52, an ignition signal output unit 53, and a fault signal output unit 54. The release command output unit 51, latch status signal output unit 52, ignition signal output unit 53, and fault signal output unit 54 may be provided in the power supply unit 1 or in the discharge device 100 equipped with it.

[0048] (Release command output section) The release command output unit 51 outputs a release command. In this embodiment, the release command output unit 51 is composed of a handle sensor located on the door handle of the vehicle V, and outputs a release command when, for example, a user places their hand on the door handle. The release command is a command to electrically execute the release process that opens the door. When the control unit 40 receives the release command, it operates the motor 12 to drive the door latch device 6 and open the door (execute the release process). The release command output unit 51 can also be implemented with equipment other than the handle sensor (for example, a switch). The release command output unit 51 is powered by the vehicle battery 10 or the backup power supply 20.

[0049] The latch status signal output unit 52 outputs a signal indicating the status of the door latch device 6. The latch status signal output unit 52 is composed of, for example, a push switch attached to the fork 61, the claw 62, or a member connected thereto.

[0050] The ignition signal output unit 53 outputs an ignition signal indicating the state of the ignition switch (not shown) of the vehicle V. The ignition signal indicates, for example, ON when the engine is running and OFF when the engine is stopped. The ignition signal output unit 53 may be composed of, for example, an ECU (electronic control unit) mounted on the vehicle V.

[0051] The accident signal output unit 54 outputs a signal indicating that the vehicle V is in an accident state. The accident signal output unit 54 is composed of, for example, an acceleration sensor, a millimeter-wave radar, etc.

[0052] The control unit 40 is connected to the current detection unit 14, the vehicle battery voltage acquisition unit 24, the release command output unit 51, the latch status signal output unit 52, the ignition signal output unit 53, and the fault signal output unit 54, and acquires the signals (information) output from these units.

[0053] (Door latch device) The door latch device 6 is located on the door (not shown) of the vehicle V and is driven by the motor 12. The door latch device 6 includes a fork 61, a claw 62, an operating receiving member 63, a rotating member 64, a worm gear 65, and a regulating member 66. The fork 61, claw 62, and operating receiving member 63 constitute the latch mechanism 60. The door latch device 6 (latch mechanism 60) switches between a latched state, in which the striker 9 is held, and a released state, in which the striker 9 can be released, by the rotation of the claw 62. The striker 9 is located on the body (not shown) of the vehicle V.

[0054] The configuration of the door latch device 6 will be described in detail below with reference to Figures 2 and 3. Figures 2 and 3 are schematic diagrams showing the latch mechanism 60, the rotating member 64, and the regulating member 66 in plan view. Figure 2 shows the rotating member 64 in the first position (initial position) with the door closed, and Figure 3 shows the rotating member 64 in the second position (operating position) with the door open.

[0055] As shown in Figures 2 and 3, the fork 61 has a retaining groove 611 for holding the striker 9 and a locking receiving portion 612 that is engaged by the claw 62. The fork 61 is rotatable about a first rotation axis AX1. More specifically, the fork 61 is rotatable between a fully latched position that holds the striker 9 (see Figure 2) and an open position that allows the striker 9 to be released (see Figure 3). The fork 61 is biased toward the open position by a biasing member (not shown), such as a torsion spring.

[0056] The claw 62 has a locking portion 621 that locks onto the locking receiving portion 612 of the fork 61. The claw 62 is rotatable about a second rotation axis AX2 which is parallel to the first rotation axis AX1. Specifically, the claw 62 is rotatable between a locked position (see Figure 2) that locks onto the fork 61 in the fully latched position and an unlocked position (see Figure 3) that releases the lock from the fork 61. The claw 62 is biased toward the locked position by a biasing member (not shown), such as a torsion spring.

[0057] The operating receiving member 63 is rotatable about a coaxial axis (second rotation axis AX2) with the rotation center of the claw 62 and rotates integrally with the claw 62. The operating receiving member 63 has a projection 631 that protrudes along the second rotation axis AX2 and receives operation of the rotating member 64.

[0058] The rotating member 64 is rotatable about a third rotation axis AX3 that is perpendicular to the first rotation axis AX1 and the second rotation axis AX2. As described above, Figures 2 and 3 are schematic diagrams showing the latch mechanism 60, the rotating member 64, and the regulating member 66 in plan view, and in Figures 2 and 3, the rotating member 64 is shown on the same plane as the claw 62.

[0059] The rotating member 64 has an operating part 641 that operates the claw 62 via the operating receiving member 63.

[0060] The rotating member 64 has helical teeth and meshes with a worm gear 65 connected to the output shaft of the motor 12. The rotating member 64 is rotatable in a first direction R1 and a second direction R2 opposite to the first direction R1 by power transmitted from the motor 12 via the worm gear 65. By rotating, the rotating member 64 switches its position between the first and second directions. The first direction is the initial position of the rotating member 64, and the second direction is the operating position in which the movement of the claw 62 can be controlled. In the second direction, the operating part 641 contacts and presses the protrusion 631 of the operating receiving member 63. By rotating the rotating member 64 to the first direction R1, the claw 62 rotates from the locked position to the unlocked position. In the first direction, the operating part 641 is not in contact with the operating receiving member 63.

[0061] The restricting member 66 restricts the rotation of the rotating member 64 to the second direction R2. In this embodiment, the restricting member 66 is positioned to contact the rotating member 64 in its initial position, and restricts the rotation of the rotating member 64 from rotating further in the second direction R2 than its initial position. However, the restricting member 66 may also be positioned at a position where the rotating member 64 has rotated further in the second direction R2 by a preset set rotation angle from its initial position. The set rotation angle is, for example, set to a value such that the rotating member 64 does not come into contact with surrounding members.

[0062] Next, we will explain the operation of the door latch device 6 when the motor 12 rotates in both forward and reverse directions.

[0063] For example, when the door shown in Figure 2 is in the closed position, the motor 12 rotates in a first rotational direction (for example, forward rotation), causing the rotating member 64 to rotate to a first orientation R1 and to a second position in which the operating part 641 contacts the protruding part 631. With the protruding part 631 in contact with the operating part 641, the rotating member 64 rotates further to the first orientation R1, causing the protruding part 631 to be pressed by the operating part 641. When the protruding part 631 is pressed by the operating part 641, the operating receiving member 63 and the claw 62 rotate together to a third orientation R3, causing the claw 62 to move from the locked position to the unlocked position shown in Figure 3. As a result, the locking of the claw 62 to the fork 61 is released, and the fork 61 moves from the fully latched position (see Figure 2) to the open position (see Figure 3) by the biasing force of the biasing member.

[0064] On the other hand, if the motor 12 rotates in a second direction opposite to the first direction of rotation (reverse rotation) from the state shown in Figure 3, the rotating member 64 rotates in the second direction R2. When the rotating member 64 rotates in the second direction R2, the operating part 641 moves away from the protruding part 631. When the operating part 641 moves away from the protruding part 631, the biasing force of the biasing member causes the claw 62 and the operating receiving member 63 to rotate together in the fourth direction R4, and the claw 62 moves from the unlocked position shown in Figure 3 to the locked position shown in Figure 2. The fork 61 can be in the fully latched position when the door is closed and the striker enters the retaining groove 611 and presses against the fork 61. Alternatively, the fork 61 can be in the fully latched position by a closure mechanism (not shown). The closure mechanism has an actuator (not shown) and a closure lever (not shown).

[0065] Next, referring to Figure 4, a second discharge process (an example of a discharge process) in which the backup power supply 20 is discharged by operating the motor 12 will be described. Note that the second discharge process is performed repeatedly while the ignition switch is ON.

[0066] As shown in Figure 4, the control unit 40 determines whether or not it has received a signal from the ignition signal output unit 53 indicating that the ignition switch is off, that is, whether or not the ignition switch has switched from on to off (step S1). If the control unit 40 determines that the ignition switch has not switched from on to off (step S1; NO), it terminates the second discharge process.

[0067] On the other hand, when the control unit 40 determines that the ignition switch has switched from on to off (step S1; YES), it determines whether the output voltage of the vehicle battery 10 is above a predetermined voltage based on the information output from the vehicle battery voltage acquisition unit 24 (step S2). When the control unit 40 determines that the output voltage of the vehicle battery 10 is not above the predetermined voltage and is below the predetermined voltage (step S2; NO), it terminates the second discharge process.

[0068] On the other hand, if the control unit 40 determines that the output voltage of the vehicle battery 10 is above a predetermined voltage (step S2; YES), it determines whether the output voltage of the backup power supply 20, that is, the detected voltage detected by the control unit 40, is above a first threshold voltage (step S3). If the control unit 40 determines that the detected voltage is not above the first threshold voltage, that is, below the first threshold voltage (step S3; NO), it terminates the second discharge process.

[0069] On the other hand, when the control unit 40 determines that the detected voltage is equal to or greater than the first threshold voltage (step S3; YES), it controls the operation of the switching unit 23 to connect the backup power supply 20 and the motor 12 via the motor drive unit 11 (step S4).

[0070] Next, the control unit 40 operates the motor 12 so that the rotating member 64 rotates in the second direction R2 (step S5). When rotating the rotating member 64 in the second direction R2, the fork 61 may be in the fully latched position or the open position.

[0071] Next, the control unit 40 determines whether the detected voltage is less than the first threshold voltage (step S6). If the control unit 40 determines that the detected voltage is not less than the first threshold voltage, but is greater than or equal to the first threshold voltage (step S6; NO), it returns to step S5.

[0072] On the other hand, when the control unit 40 determines that the detected voltage is less than the first threshold voltage (step S6; YES), it controls the operation of the switching unit 23 to disconnect the backup power supply 20 from the motor drive unit 11 (motor 12) (step S7), and terminates the second discharge process. In other words, the second discharge process is performed until the detected voltage falls below the first threshold voltage (an example of a predetermined voltage). The information indicating the first threshold voltage is stored in the memory device of the control unit 40.

[0073] As described in the above embodiment, the second discharge process performed by the control unit 40 consumes the power stored in the backup power supply 20 by operating the motor 12 until the detected voltage detected by the control unit 40 falls below the first threshold voltage. Therefore, the backup power supply 20 can be discharged more quickly compared to the case of discharge using only resistive elements. For example, in the case of discharge using only the discharge unit 22 composed of resistive elements, it takes 120 seconds to discharge the backup power supply 20, whereas according to the above embodiment, it can be discharged within 10 seconds.

[0074] In the above embodiment, the rotating member 64 rotates in a second direction R2, which is opposite to the first direction R1 that causes the claw 62 that locks the fork 61 to be in the unlocked position. This prevents the claw 62 from unintentionally being in the unlocked position and releasing the lock on the fork 61. This allows the backup power supply 20 to be discharged safely.

[0075] In the above embodiment, since the door latch device 6 has a regulating member 66, the rotating member 64 can rotate in the second orientation R2 to avoid collision of the rotating member 64 with other parts arranged around it. Therefore, the backup power supply 20 can be safely discharged.

[0076] In the above embodiment, the backup power supply 20 is provided as a backup to the onboard battery 10 in case power is not supplied from the onboard battery 10 due to, for example, an accident while driving. Therefore, when the ignition switch is switched from on to off, the backup power supply 20 does not need to store power. Accordingly, by performing the second discharge process at the timing when the ignition switch is switched from on to off, the backup power supply 20 can be discharged at an appropriate timing.

[0077] (modified version) Although embodiments have been described so far, the above configuration is merely an example and can be modified as appropriate within the scope of the present invention.

[0078] In the above embodiment, the control unit 40 discharged the backup power supply 20 by operating the motor 12 until the detected voltage fell below the first threshold voltage. However, the control unit 40 may also perform a combination of a second discharge process, in which the motor 12 discharges the backup power supply 20, and a first discharge process, in which the discharge unit 22 discharges the backup power supply 20. More specifically, the control unit 40 may discharge the backup power supply 20 by operating the motor 12 until the voltage falls below the second threshold voltage, which is greater than the first threshold voltage, and then discharge the backup power supply 20 using the discharge unit 22 until the voltage falls below the first threshold voltage. Alternatively, the control unit 40 may discharge the backup power supply 20 by operating the motor 12 for a preset time (for example, 3 seconds), and then discharge the backup power supply 20 using the discharge unit 22 until the voltage falls below the first threshold voltage.

[0079] In the above embodiment, the case in which the power supply unit 1 is applied to the door latch device 6 was described, but the power supply unit 1 can also be applied to other devices such as electric tailgates, electric fuel lids, and electric side mirrors.

[0080] In the above embodiment, the case where motor 12 is a low-voltage motor was described, but motor 12 does not have to be a low-voltage motor; it may be a motor with an operating voltage of 9V to 16V.

[0081] In the above embodiment, the case in which the backup power supply 20 is discharged by operating the motor 12 that drives the door latch device 6 during the second discharge process was described. However, the backup power supply 20 may also be discharged by operating motors that drive other in-vehicle electric devices (such as power windows and door handles).

[0082] Furthermore, in the above embodiment, the door latch device 6 is equipped with a rotating member 64 that operates the rotation of the claw 62, but the door latch device 6 may omit the rotating member 64, and the motor 12 may be directly connected to the operating receiving member 63 or the claw 62. In other words, in the second discharge process, the operating receiving member 63 or the claw 62 may be rotated by operating the motor 12. This allows the power stored in the backup power supply 20 to be consumed, and thus the backup power supply 20 can be discharged quickly. [Explanation of Symbols]

[0083] 1 Power supply 5. Signal Output Section 6. Door latch device 9 Striker 10. Car battery 11 Motor drive unit 12 motors 13 Pre-driver 14 Current detection unit 20 Backup power supply 20A capacitor 20b Capacitor 21 Live parts 22 Discharge section 22a Discharge control line 22b Discharge control line 23 Switching section 23a Main switch element 23b Sub-switch element 24. Vehicle battery voltage acquisition unit 25 Voltage Stabilizer 40 Control Unit 51 Release command output section 52 Latch status signal output section 53 Ignition signal output section 54. Fault signal output section 60 Latch mechanism 61 Forks 62 Claws 63 Operation receiving member 64 Rotating Member 65 Worm Gear 66 Regulating members 100 Vehicle power supply discharge device 611 Retaining groove 612 Locking receiver 621 Locking part 631 Protrusion 641 Operation section AX1 First rotation axis AX2 Second Rotation Axis AX3 Third Rotation Axis D1 First Diode D2 Second Bypass GL Ground Line L1 Main feed line L2 sub-feed line L3 charging line L4 Main control power line L5 Sub-control power line L6 Main drive line L7 auxiliary drive line V Vehicle

Claims

1. A backup power supply to serve as a backup for the onboard battery installed in the vehicle, A motor that operates by receiving power from the onboard battery or the backup power supply, The control unit, which can detect the voltage of the backup power supply and controls the operation of the motor, Equipped with, The control unit is a vehicle power supply discharge device that performs a discharge process to operate the motor with power supplied from the backup power supply until the detected voltage, which is the voltage of the backup power supply detected, falls below a predetermined voltage.

2. A fork that can rotate between a fully latched position that holds the striker and an open position that allows the striker to be released, A claw that is rotatable between a locking position that locks the fork in the full latch position and an unlocking position that releases the locking of the fork. Furthermore, The vehicle power discharge device according to claim 1, wherein the control unit rotates the claw by operating the motor during the discharge process.

3. The device further comprises a rotating member that is rotatable to a first orientation and a second orientation, and which rotates the claw from the locked position to the unlocked position by rotating to the first orientation, The vehicle power discharge device according to claim 2, wherein the control unit rotates the rotating member to a second direction by operating the motor during the discharge process.

4. The vehicle power discharge device according to claim 3, further comprising a restricting member that restricts the rotation of the rotating member to the second direction.

5. The vehicle power supply discharge device according to claim 1 or 2, wherein the control unit performs the discharge process when the ignition switch is switched from on to off.

6. The vehicle power supply discharge device according to claim 1 or 2, wherein the backup power supply is composed of an electric double-layer capacitor.

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