Vehicle door latch device

Abstract

To provide a door latch device for vehicles having a backup power capable of supplying electric power with high output and high efficiency with a smaller electric power loss of the backup power.SOLUTION: The door latch device for vehicles includes: an actuator driven by a motor; a control unit that controls the drive of the motor; a main power supply unit for supplying the power to the control unit and the motor; a backup power supply that supplies the power instead of the main power supply unit in the event of a vehicle failure; and a booster for boosting the voltage of the backup power supply. The door latch device for vehicles further includes: a boost power supply line that connects from the backup power supply to the control unit via a boost unit; and a non-boosted power supply line that connects the drive unit and the backup power supply.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a vehicle door latch device.

Background Art

[0002] It is known to employ an electric door latch device for the doors of vehicles such as automobiles. Conventionally, in an electric door latch device, power is supplied from a main power source installed on the vehicle side to the door latch device provided on the door via a wiring for power supply.

[0003] On the other hand, in case the power from the main power source to the door latch device is cut off due to an accident of the vehicle or the like, a door latch device provided with an emergency backup power source using a supercapacitor has been developed. For example, a door latch device according to Japanese Patent Application Laid-Open No. 2016-503135 is described.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Generally, a supercapacitor used as a backup power source has a limited supply voltage. For this reason, it has been necessary to boost the voltage using a boost module in order to supply a sufficient voltage to drive a motor for locking or unlocking the door latch.

[0006] In addition, when trying to integrally accommodate the backup power source in the door latch device provided on the vehicle door, it has to be arranged in a limited space and the power supply capacity is also limited, so it has been difficult to obtain a high output.

Means for Solving the Problems

[0007] A vehicle door latch device according to an embodiment of the present invention includes an operating part driven by a motor, a control part that controls the driving of the motor, a main power supply part that supplies power to the control part and the motor, a backup power supply part that supplies power in place of the main power supply part when a vehicle failure occurs, and a boosting part that boosts the voltage of the backup power supply part. In the vehicle door latch device having these components, there is a boosted power supply line that connects from the backup power supply part to the control part via the boosting part, and an unboosted power supply line that connects the operating part and the backup power supply part.

Effects of the Invention

[0008] According to the vehicle door latch device according to an embodiment of the present invention, it is possible to provide a door latch device that has less power loss in the boosting part and can supply power with high output and high efficiency.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of this invention will be described with reference to the drawings. Note that, for elements common to the respective figures, redundant explanations may be omitted.

[0011] FIG. 1 is a diagram for explaining a vehicle door latch device according to an embodiment of the present invention.

[0012] Figure 1 schematically shows a vehicle 100 and a vehicle door 110. The vehicle 100 is a vehicle such as an automobile, for example, and the vehicle door 110 is fixed to the vehicle 100 so as to be openable and closable via a door hinge, for example.

[0013] The vehicle 100 has a main power supply unit 101 that supplies power to the vehicle door 110. Although not particularly limited, the main power supply unit 101 is configured using a storage battery such as a lead storage battery that is widely used as an automotive battery. Further, such a main power supply unit 101 is capable of outputting, for example, 12V, which is a standard voltage in an automobile.

[0014] The door latch unit 111 disposed on the vehicle door 110 has an operating group 154 including, for example, a ratchet that can selectively rotate with respect to a striker fixed to a door post, and a pole that is rotationally driven by a motor and blocks the rotation of such a ratchet. The motor 153 performs locking and / or unlocking of the vehicle door 110 by driving such an operating group.

[0015] Such a door latch unit 111 has an operating unit 150 including a motor 153, a driver 152 that drives the motor 153, and a pre-driver 151 (hereinafter also referred to as a second control unit).

[0016] Further, the door latch unit 111 has a control unit 130 that controls the driver 152 and the like of the operating unit 150, and a power supply circuit unit 120 that supplies power from the main power supply unit 101 to the operating unit 150 and the control unit 130.

[0017] As will be described later, a motor that can be driven at about 3V to 5V is used for the motor 153 so that it can be driven by the non-boost voltage of the auxiliary power supply unit 161 in the event of a vehicle failure. Further, the motor 153 needs to have sufficient output to rotate the ratchet.

[0018] During normal operation when the main power supply unit 101 supplies power, the main power supply supplies power to the driver 152 via the power line 102, the switching unit 121, and the power line 103. The switching unit 121 is a switch whose on / off state is controlled by the control unit 130. During normal operation, the switching unit 121 is in the on state. Note that the switching 121 can be realized, for example, by a configuration in which power MOSFETs are connected back-to-back (source common connection).

[0019] Also, during normal operation when the main power supply unit 101 also supplies power, the main power supply supplies power to the pre-driver 151 via the power line 104.

[0020] The control unit 130 includes, for example, a central processing unit (CPU) constituted by a microprocessor, and the main power supply unit 101 also supplies power to the CPU 131.

[0021] Generally, an arithmetic unit such as a microprocessor requires a stable power supply for its accurate operation. Also, the power supply voltage of a large-scale integrated circuit (LSI) constituting the microprocessor tends to decrease with the miniaturization of the integrated circuit and is often lower than the standard voltage for automobiles. Therefore, in this embodiment, a voltage regulator unit 122 is provided in the power supply circuit unit 120. The voltage of the main power supply unit 101 is stepped down to about 5V by the voltage regulator unit 122, stabilized, and then supplied to the CPU 131.

[0022] The vehicle door 110 further has a sensor unit 140. When an occupant of the vehicle or the like operates an operation handle to lock and / or unlock the vehicle door, the sensor unit 140 detects the operation and sends a detection signal to the CPU 131 of the control unit 130. Upon receiving such a detection signal, the CPU 131 controls the pre-driver 151 and / or the driver 152 of the operating unit 150 to drive the motor 153. Thereby, the locking and / or unlocking of the vehicle door 110 is performed. The operation handle is a door latch switch for an occupant or the like to operate the locking and / or unlocking of the door, and includes both an outer handle installed outside the vehicle 100 and an inner handle arranged inside the vehicle 100.

[0023] As described above, although the main power supply unit 101 is expected to provide power constantly, in an emergency such as a vehicle accident, the power supply from the main power supply unit 101 may be cut off, or the power supply may be interrupted due to a disconnection of the power line or the like. Therefore, in the door latch unit 111 shown in FIG. 1, a backup power supply unit 160 for supplying power to the control unit 130 and / or the operating unit 150 is provided in the event of a vehicle failure state where the power supply from the main power supply unit 101 is interrupted.

[0024] The backup power supply 161 of the backup power supply unit 160 is configured using, for example, a supercapacitor (sometimes called an ultracapacitor). The supercapacitor includes an electric double layer capacitor, a pseudo capacitor, or a capacitor combining these.

[0025] By providing such a backup power supply unit 160, the operating unit 150 can be surely operated even in a vehicle accident state where the main power supply is interrupted, and the locking operation or unlocking operation of the vehicle door can be ensured well.

[0026] Supercapacitors have a high energy density, high output current characteristics, and a relatively small size, so they are suitable as a backup power supply unit provided in a vehicle door. However, the supply voltage is limited. Also, when provided in a door latch device provided in a vehicle door, it must be arranged in a limited space, and the power supply capacity is also limited.

[0027] Due to these circumstances, the maximum supply voltage by the supercapacitor may be limited to about 3V to 5V. Although not particularly limited, the maximum voltage of the supercapacitor used here is about 2.5V, and it is configured such that a maximum voltage of about 5V can be obtained by connecting two capacitors in series.

[0028] The backup power supply unit 160 is further provided with an equivalent circuit unit 162, and is controlled to equalize the stored voltage for each supercapacitor based on an instruction from the CPU 131.

[0029] Also, the backup power supply unit 160 further has a charging unit 163. The charging unit 163 controls to charge the backup power supply 161 with the power from the main power supply unit 101 during normal operation.

[0030] Also, the backup power supply unit 160 further has a boosting unit 164. The voltage of the backup power supply 161 is boosted by the boosting unit 164 and supplied to the pre-driver 151 and the voltage regulator 122 via the power supply line 107 (boosting power supply line).

[0031] On the other hand, the power of the backup power supply 161 is also supplied to the driver 152 via the power supply line 105 (non-boosting power supply line), the switching element 123, and the power supply line 106 (non-boosting power supply line) without passing through the boosting unit 164. The switching of the switching element 123 is controlled by the CPU 131 of the control unit 130, and its configuration can be the same as that of the switching unit 121.

[0032] Here, according to the present embodiment, by providing the boosting unit 164, even when the space for installing the backup power supply 161 is limited and the number of supercapacitors to be installed is limited, it is possible to supply the necessary voltage. Further, even when the power of the backup power supply is consumed by motor driving, the control unit can be supplied with the boosted voltage, so that the control unit can operate stably.

[0033] Furthermore, the boost power supply line that supplies the boosted voltage from the boosting unit 164 is supplied to the voltage regulator 122 and the pre-driver 151 for driving the CPU 131, but power is supplied to the driver 150 without passing through the boost circuit. Therefore, it is possible to provide a door latch device that minimizes power loss in the boost circuit and can supply power with high output and high efficiency.

[0034] Also, since the switching element 123 is provided between the power supply line 105 and the power supply line 106 which are non-boost power supply lines, the power consumption of the backup power supply 161 can be suppressed by turning off the switching element 123 during normal operation.

[0035] Next, a series of operations in the event of a vehicle failure in the present embodiment will be described.

[0036] The CPU 131 of the control unit 130 monitors whether power is being normally supplied from the main power supply unit 101, for example, by monitoring the voltage supplied from the main power supply unit 101 or the output voltage of the voltage regulator 122. The control unit 130 can be configured to detect a state in which the voltage of the main power supply has dropped to a certain extent as a vehicle failure state, not limited to the case where the power from the main power supply is completely interrupted.

[0037] When the control unit 130 detects that the power from the main power supply unit 101 has been interrupted, the control unit 130 controls the switching unit 121 to be in the off state. In the figure, the signal lines through which control signals and detection signals are sent are schematically shown as broken lines.

[0038] In this vehicle failure state, power is supplied from the backup power supply unit 160. When the operation handle is operated, the sensor unit 140 connected to the backup power supply 161 and receiving power supply detects the operation, and sends operation detection signals indicating the detection of the operation to the CPU 131 and the booster unit 164, respectively.

[0039] Upon receiving the operation detection signal, the booster unit 164 boosts the voltage of the backup power supply 161 and supplies it to the boosted power supply line 107. The start of this boosting operation can be based on a control signal from the CPU 131. Here, however, the operation detection signal from the sensor unit 140 is also supplied to the booster unit 164, and the boosting operation is directly started by such a signal. As a result, it is possible to stabilize the boosted voltage at an early stage and stabilize the startup of the control unit 130 at an early stage. Also, with such a configuration, the boosting operation can be started even when the control unit does not start in a vehicle emergency state or the like described later. For this reason, the booster unit 164 can further include a boosting control unit (not shown) that receives the operation detection signal from the sensor unit 140 and performs boosting control.

[0040] Next, the CPU 131 of the control unit 130 controls the switching unit 123 to be in an on state, and supplies the power of the backup power supply 161 to the driver 152. Thereafter, the CPU 131 drives the motor 153 via the pre-driver 151. Thereby, the door latch is locked or unlocked.

[0041] In this way, in the present embodiment, by providing a boosted power supply line that supplies a voltage obtained by boosting the voltage of the backup power supply and a non-boosted power supply line that supplies the voltage of the backup power supply without boosting, it is possible to provide the necessary power to each part with high efficiency.

[0042] According to an embodiment of the present invention, the vehicle 100 may further include a collision sensor or an acceleration sensor. In FIG. 1, an example in which the collision sensor 170 is provided on the vehicle door 110 is shown. However, the collision sensor 170 is not limited to this and can also be provided in other parts of the vehicle 100.

[0043] In this embodiment, when a failure of the main power supply is detected, the system switches to using the backup power supply unit. However, it is not limited to this. The control unit may also switch to using the backup power supply unit when it receives a vehicle emergency state signal from the collision sensor 170, or based on a combination of the vehicle emergency state signal and the state of the main power supply unit.

[0044] Also, the CPU 131 that has received the vehicle emergency state signal from the collision sensor 170 can be configured to invalidate the detection signal of the steering wheel operation from the sensor unit 140 during the period when the vehicle emergency state signal is being issued, or for a predetermined time after receiving the vehicle emergency state signal, or to output a locking maintenance signal. This can disable the unlocking of the vehicle door for a certain period in the event of a vehicle collision, etc., and prevent the door from being opened even if the steering wheel is accidentally touched, thus ensuring the safety of the passengers and the like.

[0045] FIG. 2 and FIG. 3 show more specific aspects of the door latch device shown in FIG. 1, particularly the operating part. In each figure, the parts the same as those in FIG. 1 are not described again.

[0046] The operating part 250 of the door latch device in FIG. 2 includes a motor 253 and an H-bridge circuit that is a driver for driving the motor 253. The H-bridge circuit is composed of transistors 254, 255, 256, and 257, each of which is an n-type FET.

[0047] The operating part 250 also has a pre-driver 251. The pre-driver 251 receives a control signal from the CPU 131 of the control unit 130 and drives the motor 253 by performing on / off control of each transistor of the H-bridge circuit.

[0048] Here, in the event of a vehicle failure state, the pre-driver 251 is configured to receive the voltage boosted by the boosting part 164 via the boost power supply line. On the other hand, the H-bridge circuit, which is the driver, is configured to be supplied with the non-boosted voltage via the non-boost power supply line in the event of a vehicle failure state.

[0049] In this way, by supplying a boosted voltage to the pre-driver 251 and a non-boosted voltage to the driver, a voltage (e.g., 10V which is the boosted voltage) sufficiently higher than the voltage applied to the source-drain electrodes (e.g., 5V of non-boosted power) can be applied to the gate electrodes of the n-type FETs constituting the H-bridge circuit, and the motor 253 can be driven normally. Also, since the pre-driver circuit for controlling the driving of the H-bridge circuit consumes relatively little power, even if it is driven with the boosted voltage, the power consumption can be relatively small. Thereby, the power loss in the boost circuit can be reduced, and the power of the backup power source can be used with high efficiency.

[0050] Also, by providing the pre-driver 251, adjustment control such as PWM control of the motor can be easily performed by the pre-driver, and adjustment control such as preventing malfunction of the operating part can be easily performed.

[0051] The operating part 350 of the door latch device in FIG. 3 includes a motor 353 and an H-bridge circuit which is a driver for driving the motor 353. The H-bridge circuit is composed of high-side transistors 354 and 355 each composed of a p-type FET, and low-side transistors 356 and 357 each composed of an n-type FET.

[0052] Also, the operating part 350 is connected with, as pre-drivers, a transistor 361 which is an npn-type bipolar transistor whose collector electrode is connected to the gate electrode of the transistor 354, a transistor 362 which is an npn-type bipolar transistor whose collector electrode is connected to the gate electrode of the transistor 355, a transistor 363 which is a pnp-type bipolar transistor whose collector electrode is connected to the gate electrode of the transistor 356, and a transistor 364 which is a pnp-type bipolar transistor whose collector electrode is connected to the gate electrode of the transistor 357, respectively.

[0053] Here, each bipolar transistor of the pre-driver has its base electrode connected to the CPU 131 of the control unit 130. The CPU 131 controls the on / off of each bipolar transistor by a control signal, thereby controlling the on / off of each transistor 354, 355, 356, and 357 of the driver and driving the motor 353.

[0054] According to the form shown in FIG. 3, since a p-type FET is used on the high side of the H-bridge circuit and an n-type FET is used on the low side, it is possible to directly drive the pre-driver by the CPU 131 using the voltage stepped down by the voltage regulator 122. Also, since the H-bridge circuit itself is driven by a non-boost voltage, power loss in the boost circuit can be reduced, and the power of the backup power supply can be used with high efficiency.

[0055] As described above, with reference to FIGS. 2 and 3, a more specific aspect of the operating unit has been described, but the embodiments of the present invention are not limited thereto.

[0056] For example, a driver IC for driving a motor that operates with a non-boost voltage can be provided, and the motor can be driven by directly controlling the driver IC by the CPU without using a pre-driver.

[0057] Also, for example, the transistor on the high side of the H-bridge circuit shown in FIG. 2 can be composed of a pnp bipolar transistor whose emitter electrode is connected to the boost voltage and whose collector electrode is connected to the gate electrode of the n-type FET on the high side.

[0058] As described above, according to the embodiments of the present invention, it is possible to provide a door latch device that has little power loss in the boost circuit and can supply power with high output and high efficiency.

[0059] In addition, conventional vehicle electric and electronic components are configured to be compatible not only with motors but also with lead-acid batteries (12V system). In the future, when electric vehicles become popular and the need for a backup power supply increases, in a circuit configuration with a boost circuit, a supercapacitor cannot be effectively utilized, so it is possible to make the electric and electronic components compatible with the backup power supply.

[0060] Note that the backup power supply unit can also be configured with a capacitance element other than a supercapacitor, and furthermore, it can also be configured with a secondary battery such as a nickel-metal hydride battery.

[0061] In addition, in the embodiment of the present invention, although one vehicle door has been typically described, the door latch device of this embodiment can also be provided on each door of the vehicle.

[0062] In addition, the vehicle door shown in the embodiment of the present invention may be any type of door that is rotatably provided with respect to the vehicle, such as a normal type of door, a sliding door, a double-opening door, a gull-wing door, etc. Depending on the type of door, the location where it is arranged, the number, etc., it is also possible to appropriately select the vehicle door for which a backup power supply is provided.

[0063] In addition, although a door latch motor has been exemplified as an example of each actuator unit, the actuator unit is not limited to a motor, and an actuator using a solenoid or the like can also be used.

[0064] In addition, each switching unit can also be configured by, for example, a relay element, a semiconductor relay, a power transistor, an FET, or the like.

[0065] As described above, the embodiments according to the present invention have been explained. In addition to this, the embodiments of the present invention also include the following forms.

[0066] (1) A vehicle door latch device having an operating part driven by a motor, a control part for controlling the drive of the motor, a main power supply part for supplying power to the control part and the motor, a backup power supply part for supplying power in place of the main power supply part in case of a vehicle failure, and a boosting part for boosting the voltage of the backup power supply of the backup power supply part, wherein the vehicle door latch device has a boosted power supply line for supplying power from the backup power supply to the control part via the boosting part and a non-boosted power supply line for supplying power from the backup power supply to the operating part.

[0067] (2) Further having a sensor part for detecting the operation of an operation handle provided on a vehicle door, and when the sensor part detects the operation of the operation handle, the detection signal is input to the control part and the boosting part.

[0068] (3) The boosting part further has a boosting control part for starting and controlling the boosting part according to the detection signal.

[0069] (4) When the control part detects a vehicle emergency state signal, the control part invalidates the input of the detection signal and / or outputs a signal for maintaining the locked state.

[0070] (5) Having a drive control part for adjusting the control of the drive circuit according to the signal of the control part between the control part and the operating part, and the drive control part and the boosting part are connected by the boosted power supply line. (6) A switching part controlled by the control part is provided on the non-boosted power supply line.

Explanation of symbols

[0071] 100 Vehicle 101 Main power supply part 102, 103, 104, 105, 106, 107 Power supply line 110 Vehicle door 111 Door latch part 120 Power supply circuit part 121 and 123 switching elements 122 voltage regulator section 130 control section 131 CPU 140 sensor section 150, 250, and 350 operating sections 151 and 251 pre-drivers 152 driver 153, 253, and 353 motors 154 operating group 160 backup power supply section 161 backup power supply 162 equivalent circuit section 163 charging section 164 boosting section 170 collision sensor 254, 255, 256, and 257 transistors 354, 355, 356, 357, 361, 362, 363, and 364 transistors

Claims

1. An operating part driven by a motor, a control part that controls the driving of the motor, a main power supply part that supplies power to the control part and the motor, a backup power supply that supplies power in place of the main power supply in the event of a vehicle failure, a boosting part that boosts the voltage of the backup power supply, a boosted power supply line that is coupled from the backup power supply to the control part via the boosting part, a non-boosted power supply line that couples the operating part and the backup power supply, and has, a sensor part that detects the operation of an operation handle provided on a vehicle door, A vehicle door latch device, wherein when the sensor part detects the operation of the operation handle, the detection signal is sent to the control part and also sent to the boosting part.

2. The vehicle door latch device according to claim 1, wherein the boosting part has a boosting control part that activates the boosting part in response to the detection signal.

3. The vehicle door latch device according to claim 1 or claim 2, wherein when the control part detects a vehicle emergency state signal, the input of the detection signal is invalidated or a locking maintenance signal is output.

4. A drive control part that controls the driving operation of the operating part according to the signal of the control part is provided between the control part and the operating part, The vehicle door latch device according to claim 1, wherein the drive control part and the boosting part are coupled by the boosted power supply line.

5. The vehicle door latch device according to any one of claims 1 to 3, wherein the operating part and the backup power supply are coupled by the non-boosted power supply line via a switching part controlled by the control part.

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