Door latch device

Abstract

The present invention relates to a door latch device capable of motorizing a child lock mechanism of the door latch device while suppressing an increase in the number of components and a consequent complication of the structure. In a child lock state in which a child lock signal is received from a child lock change-over switch (17), when a lock change-over signal indicating that a lock plate (31) moves from a lock position to an unlock position is received from a lock state detection switch (18), a control unit (20) of a door latch device (1) drives a lock mechanism motor (10) to move the lock plate (31) from the unlock position to the lock position.

Description

Technical Field

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

[0002] The vehicle door latch device described in Patent Document 1 includes: a locking mechanism that can switch between a state in which the handle operation for opening the door is effective (unlocked state) and an invalid state (locked state). In addition, the door latch device includes: an override mechanism that switches the locking mechanism from the locked state to the unlocked state only by operating the inner handle in the handle. Specifically, the first operation of the inner handle can switch the locked state to the unlocked state, and the second operation of the inner handle can release the latch mechanism. In addition, the door latch device includes a child lock mechanism. If the child lock mechanism is in the activated state, that is, the child lock state, even if the inner handle is operated, the override mechanism will not function, the locking mechanism will remain in the locked state, the latch mechanism will not be released, and the door will not open.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2009-052229

[0006] In recent years, there has been a growing desire to electrify child lock mechanisms. However, electrifying a child lock mechanism requires a dedicated motor separate from the motor used for the locking mechanism, which increases the number of parts and complicates the structure. Summary of the Invention

[0007] The technical problem of the present invention is to motorize the child lock mechanism of a door latch device while suppressing an increase in the number of components and the resulting complexity of the structure.

[0008] The latch mechanism is adapted to move the latch member between an unlocked position and a locked position, wherein the latch member is adapted to move the latch member between the unlocked position and the locked position, and ... The rotational force of the internal opening rod is transmitted to the pawl; an override mechanism can transfer the locking member from the locked position to the unlocked position by rotating the internal opening rod; a child lock operation receiving unit can receive a selection operation of using and not using the child lock mechanism, and if the accepted selection operation is to use the child lock mechanism, a child lock signal is output; if the accepted selection operation is not to use the child lock mechanism, a child lock release signal is output; and a control unit can receive the child lock signal and the child lock release signal from the child lock operation receiving unit, and can receive the lock switching signal from the lock member position detection unit. In the child lock state where the child lock signal is received from the child lock operation receiving unit, when the lock switching signal is received from the lock member position detection unit, the control unit drives the lock mechanism motor to move the lock member from the locked position to the unlocked position.

[0009] The internal opening lever rotates in conjunction with operation of the inside handle, causing the override mechanism to move the locking member from the locked position to the unlocked position. However, if the door is in the child lock state, having received a child lock signal from the child lock operation reception unit, then when the override mechanism moves the locking member from the locked position to the unlocked position, and the control unit receives a lock switching signal from the locking member position detection unit, the control unit drives the locking mechanism motor to move the locking member from the unlocked position to the locked position. In this way, the child lock mechanism is implemented by the control unit controlling the locking mechanism motor, eliminating the need for a dedicated motor for the child lock mechanism. Consequently, the child lock mechanism of the door latch device can be motorized while suppressing the cost increases associated with an increased number of components and a more complex structure.

[0010] Effects of the Invention

[0011] According to the door latch device of the present invention, the child lock mechanism of the door latch device can be motorized while suppressing an increase in the number of components and the resulting complication of the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a block diagram showing the configuration of a latch device according to an embodiment of the present invention.

[0013] Figure 2 This is a schematic diagram showing a locking mechanism that also functions as a child lock mechanism and an override mechanism (locked state when the child lock is released).

[0014] Figure 3 This is a schematic diagram showing the locking mechanism that also functions as a child lock mechanism and the override mechanism (first inside lever operation when releasing the child lock).

[0015] Figure 4 This is a schematic diagram showing the locking mechanism that also functions as a child lock mechanism and the override mechanism (the first inside lever operation is completed when the child lock is released).

[0016] Figure 5 This is a schematic diagram showing the locking mechanism that also functions as a child lock mechanism and the override mechanism (second inside lever operation when releasing the child lock).

[0017] Figure 6 This is a schematic diagram showing a locking mechanism that also functions as a child lock mechanism and an override mechanism (in the case of a child lock, the operation starts when the control unit receives an unlocked state detection signal).

[0018] Figure 7 This is a schematic diagram showing a locking mechanism that also functions as a child lock mechanism and an override mechanism (the operation ends when the control unit receives an unlocked state detection signal in the case of a child lock).

[0019] Description of Reference Numerals

[0020] 1: Latch device; 2: Latch mechanism; 3: Strike pin; 4: Fork; 4a: Shaft; 5: Pawl; 5a: Shaft; 5b: Operating unit; 6: Electric release lever; 6a: Shaft; 6b: Gear unit; 7: Electric release motor; 7a: Worm gear; 8: Inside handle; 9: Lock mechanism; 10: Lock mechanism motor; 10a: Gear; 11: Override mechanism; 12: Emergency lever; 15: Unlatch switch; 16: Lock status switch; 17: Child lock switch (child lock operation receiving unit); 18: Lock status detection switch (lock member position detection unit); 1 9: Emergency sensor; 20: Control unit; 21: Alarm generating unit; 22: Child lock mechanism; 31: Locking plate (locking member); 31a: Shaft; 31b: Arm; 31c: Arm; 31d: Pin; 32: Connecting rod; 32a: Output unit; 23b: Long slot; 33: Joint; 33a: Slot hole; 33b: Slot hole; 34: Internal opening rod; 34a: Shaft; 34b: Arm; 34c: Operating unit; 34d: Arm; 34e: Rotary joint; 35: Spring; 36: Override lever; 36a: Shaft; 36b: Arm; 36c: Arm; 36d: Pin. DETAILED DESCRIPTION

[0021] Reference Figure 1 The door latch device 1 according to the embodiment of the present invention is provided for locking / unlocking the door of a car as an example of a vehicle. A latch mechanism 2 is provided in the door. The latch mechanism 2 comprises: a shift fork 4, which holds a striker 3 provided on the vehicle body in a manner that enables engagement / disengagement. The shift fork 4 can rotate around the shaft 4a and is elastically biased in the clockwise direction in the figure. In addition, the latch mechanism 2 comprises: a pawl 5, which can engage / disengage with the shift fork 4 and can engage with the shift fork 4 to maintain the engagement state of the shift fork 4 and the striker 3. The pawl 5 can rotate around the shaft 5a and is elastically biased in the counterclockwise direction in the figure. By rotating the operating portion 5b of the pawl 5 in the clockwise direction (described later) Figures 2 to 7 The pawl 5 can be released from engagement with the fork 4 by moving the pawl 5 upward.

[0022] The latch device 1 includes an electric release lever 6 that operates the operating portion 5b of the pawl 5 to disengage the pawl 5 from the fork 4, and an electric release motor 7 that drives the electric release lever 6. Furthermore, the latch device 1 includes a locking mechanism 9 that switches between an unlocked state, in which the pawl 5 can be disengaged from the fork 4, and a locked state, in which the pawl 5 cannot be disengaged, in response to operation (in this embodiment, pulling) of the inside handle 8. In addition to the inside handle 8, the latch device 1 includes a locking mechanism motor 10, an override mechanism 11, and a panic lever 12 as elements that operate the locking mechanism 9. Furthermore, as switches and sensors, the latch device 1 includes an unlatch switch 15, a lock state selector switch 16, a child lock selector switch 17 (child lock operation receiver), a lock state detection switch (lock member position detector) 18, and a panic sensor 19. The signals outputted from these components are inputted to the control unit 20 , and the control unit 20 controls the electric release motor 7 and the locking mechanism motor 10 based on the inputted signals.

[0023] The door latch device 1 has an electric release function, an electric lock function, an override function, and a child lock function.

[0024] For electric release function, refer to Figure 1 , the rotational driving force of the electric release motor 7 is transmitted to the electric release lever 6, so that the electric release lever 6 rotates, thereby the operating portion 5b of the ratchet 5 is operated, and the engagement of the ratchet 5 with respect to the shift fork 4 is released. Specifically, the electric release lever 6 is supported on the shaft 6a in a rotatable manner. A gear portion 6b is provided in the electric release lever 6. A worm gear 7a assembled to the output shaft of the electric release motor 7 is engaged with the gear portion 6b. The rotational output of the electric release motor 7 is transmitted to the electric release lever 6 via the worm gear 7a and the gear portion 6b, thereby the electric release lever 6 rotates and moves the operating portion 5b of the ratchet 5 to move it toward Figure 1 The unlock switch 15 receives the unlock instruction from the passenger and outputs an unlock signal. The control unit 20, which receives the unlock signal, drives the electric release motor 7 to rotate the electric release lever 6, thereby releasing the engagement of the pawl 5 with the fork 4.

[0025] The electric locking function operates the locking mechanism 9 by driving the locking mechanism motor 10, thereby switching the locking mechanism 9 between an unlocked state and a locked state. The lock state switching switch 16 receives a lock instruction operation and an unlock instruction operation from the passenger and outputs a lock signal or an unlock signal. Upon receiving the lock signal or unlock signal, the control unit 20 rotates the locking mechanism motor 10 in the direction corresponding to the received signal. This switches the locking mechanism 9 between a locked state and an unlocked state, as described below.

[0026] The override function is achieved through the cooperation of the override mechanism 11 and the locking mechanism 9. This override function allows the locking mechanism 9 to be switched from the locked state to the unlocked state by operating the inside handle 8 while the locking mechanism 9 is in the locked state. As described below, the override function in this embodiment is a double-acting override mechanism that achieves both the switching of the locking mechanism 9 from the locked state to the unlocked state and the disengagement of the pawl 5 and the fork 4 by operating the inside handle 8 twice. The override function is inactive when the child lock function is activated, i.e., in the child lock state.

[0027] The child lock function is intended to prevent the door from being unlocked by an occupant, such as a child, operating the inside handle 8. When the child lock function is inactive, i.e., in the child lock released state, the lock mechanism 9 can be switched from a locked state to an unlocked state using an override function. However, in the child lock state, as described above, the override function is ineffective, and the lock mechanism 9 cannot be switched from a locked state to an unlocked state by operating the inside handle 8.

[0028] The child lock mechanism 22, which implements the child lock function, consists of the locking mechanism 9, the locking mechanism motor 10, the child lock selector switch 17, and the lock state detection switch 18. The child lock mechanism 22 is electrically powered, using the locking mechanism motor 10 as its power source. As previously mentioned, the locking mechanism motor 10 is used to operate the locking mechanism 9. The child lock mechanism 22 does not include a dedicated motor for implementing the child lock function other than the locking mechanism motor 10.

[0029] Reference Figure 2 and Figure 4 , the locking mechanism 9 and the override mechanism 11 are described.

[0030] The lock mechanism 9 includes, in addition to the aforementioned lock mechanism motor 10 , a lock plate (lock member) 31 , a link 32 , a joint 33 , and an inner open lever 34 .

[0031] The inside opening lever 34 is rotatable about an axis 34a. It rotates clockwise in the figure in conjunction with the pulling of the inside handle 8. A spring (not shown) elastically biases the inside opening lever 34 in the counterclockwise direction. An operating portion 34c for operating the override mechanism 11 is provided on one arm 34b of the inside opening lever 34. The other arm 34d of the inside opening lever 34 is rotatably connected to one end (the lower end in the figure) of the connecting rod 32 via a rotary joint 34e.

[0032] The locking plate 31 is rotatable about an axis 31a. It includes an arm 31b that overlaps the other end (the upper end in the figure) of the connecting rod 32, and an arm 31c that overlaps one end (the upper end in the figure) of the joint 33. Arm 31b is connected to the other end of the connecting rod via a spring 35. Specifically, one end of the spring 35 is secured to the locking plate 31, while the other end of the spring 35 passes over the front end of the arm 31b and is inserted into a slot 32b provided at the other end of the connecting rod 32, where it is retained so as to be movable along the slot 32b.

[0033] The link 32 is provided with an output portion 32a for operating the operating portion 5b of the pawl 5. When the link 32 moves upward in the figure, the output portion 32a pushes the operating portion 5b upward, thereby releasing the engagement of the pawl 5 with the fork 4.

[0034] The joint 33 is held in place so that it can only move linearly (upward and downward in the figure). A transversely extending slot 33a is provided at one end of the joint 33 (the upper end in the figure). A cylindrical pin 31d, located on the arm 31c of the locking plate 31, is inserted into this slot 33a, thereby connecting one end of the joint 33 to the locking plate 31. When the joint 33 is raised, the locking plate 31 rotates counterclockwise, and when the joint 33 is lowered, the locking plate 31 rotates clockwise. A transversely extending slot 33b is also provided at the other end of the joint 33 (the lower end in the figure). As described later, an override rod 36 of the override mechanism 11 is connected to this slot 33b.

[0035] The locking mechanism motor 10 can raise and lower the joint 33. Specifically, a gear 10a mounted on the output shaft of the locking mechanism motor 10 engages with a gear portion (not shown) provided on the joint 33. The rotational output of the locking mechanism motor 10 is transmitted to the joint 33 via the gear 10a and the gear portion, and the joint 33 is raised and lowered according to the rotational direction of the locking mechanism motor 10.

[0036] Figure 2 Indicates the locked state of the locking mechanism 9, i.e. the state where the locking plate 31 is in the locked position, Figure 4The figure shows the unlocked state of the locking mechanism 9, i.e., the locking plate 31 in the unlocked position. In the locked state, the connecting rod 32 and the operating portion 5b of the pawl 5 are offset in the horizontal direction of the figure. In the unlocked state, the connecting rod 32 and the operating portion 5b of the pawl 5 are aligned in the horizontal direction of the figure. As described above, the joint 33 rises and falls according to the rotation direction of the locking mechanism motor 10, thereby adjusting the locking plate 31 to the locked or unlocked position, switching the locking mechanism 9 between the locked and unlocked states. In this embodiment, the locking plate 31 of the locking mechanism 9 can be switched from the locked position to the unlocked position from outside the vehicle by operating the aforementioned emergency lever 12.

[0037] The override mechanism 11 includes an override lever 36. The override lever 36 is rotatable about an axis 36a. One arm 36b of the override lever 36 is operated by the operating portion 34c of the internal opening lever 34. When the operating portion 34c rotates the internal opening lever 34 clockwise in the figure, pressing the arm 36b, the override lever 36 rotates counterclockwise. A cylindrical pin 36d is provided on the other arm 36c of the override lever 36. The pin 36d is inserted into a slot 33b at the other end (the lower end in the figure) of the joint 33, connecting the arm 36c of the override lever 36 to the other end of the joint 33. When the override lever 36 rotates counterclockwise, the joint 33 rises.

[0038] Continue to refer to Figure 2 and Figure 4 , if the locking mechanism 9 is in the locked state ( Figure 2 ), the lock state detection switch 18 as an example of the lock member position detection unit is in the OFF state, and if the lock mechanism 9 is in the unlocked state ( Figure 4 ), the lock state detection switch 18 enters the on state as being pressed by the connector 33, and outputs a lock switching signal indicating that the lock mechanism 9 has switched from the locked state to the unlocked state (the lock plate 31 has moved from the locked position to the unlocked position). The output lock switching signal is received by the control unit 20. In this manner, the lock state detection switch 18 of this embodiment indirectly detects the movement of the lock plate 31 from the locked position to the unlocked position based on the position of the connector 33. However, the lock state detection switch 18 may directly detect the movement of the lock plate 31 from the locked position to the unlocked position based on the position of the lock plate 31, or may indirectly detect the movement of the lock plate 31 from the locked position to the unlocked position based on the position or posture of the link 32.

[0039] The child lock switch 17 receives a selection operation by the passenger to select whether to use the child lock mechanism 22 or not. If the selected operation is to use the child lock mechanism 22, the child lock signal is output. If the selected operation is to not use the child lock mechanism 22, the child lock release signal is output. The output child lock signal and child lock release signal are received by the control unit 20.

[0040] The emergency sensor 19 detects an emergency situation requiring the pawl 5 to be disengaged from the shift fork 4 by operating the inside handle 8, and outputs an emergency signal. The emergency signal is received by the control unit 20. Examples of emergency situations detected by the emergency sensor 19 include a collision with another vehicle or an obstacle, submersion in water, and a low battery level in the vehicle.

[0041] The alarm generating unit 21 is controlled by the control unit 20 and generates an alarm that can be recognized by the passengers, such as sound, image, and vibration.

[0042] Next, the operation of the latch device 1 when the inside handle 8 is operated will be described.

[0043] First, the switching of the locking mechanism 9 by the override mechanism 11 in the child lock released state, ie, when the child lock changeover switch 17 outputs a child lock release signal to the control unit 20 will be described.

[0044] Reference Figure 2 When the inside handle 8 is pulled for the first time while the locking mechanism 9 is locked, the inside opening lever 34 rotates clockwise, and the connecting rod 32 moves diagonally upward in conjunction with this rotation. As the inside opening lever 34 rotates clockwise, the operating portion 34c of the inside opening lever 34 presses the arm 36b of the override lever 36, causing it to rotate counterclockwise. Furthermore, the rotation of the override lever 36 causes the joint 33 to rise. As a result, Figure 3 As shown, the locking plate 31 is rotated counterclockwise by the joint 33, and the locking plate 31 moves from the locked position to the unlocked position. Figure 3 In this state, the output portion 32 a of the connecting rod 32 interferes with the operating portion 5 b of the pawl 5 .

[0045] When Figure 3 When the first pulling operation of the inner handle 8 is stopped in the state, the inner opening lever 34 rotates counterclockwise due to the elastic force, and the connecting rod 32 descends. In addition, when the connecting rod 32 descends, the interference between the output portion 32a and the operating portion 5b of the pawl 5 is eliminated, and the connecting rod 32 rotates clockwise around the rotary joint 34e. As a result, Figure 4 As shown, the lock plate 31 is in the unlocked position, and the output portion 32a is aligned with the operating portion 5b of the pawl 5 in the lateral direction of the figure, that is, in the unlocked state.

[0046] When Figure 4 When the inner handle 8 is pulled for the second time in the unlocked state, the inner opening lever 34 rotates clockwise, and the connecting rod 32 moves upward in conjunction with the rotation. Figure 5 As shown, the operating portion 5 b of the pawl 5 is pushed upward by the output portion 32 a of the link 32 , and the engagement of the pawl 5 with respect to the shift fork 4 is released.

[0047] Next, the operation in the child lock state, that is, when the child lock signal is output from the child lock switch 17 to the control unit 20 will be described.

[0048] Refer again Figure 2 When the first pulling operation of the inside handle 8 is performed while the locking mechanism 9 is in the locked state, the link 32 moves obliquely upward in conjunction with the clockwise rotation of the inside opening lever 34, and the joint 33 rises due to the rotation of the override lever 36. As a result, Figure 3 As shown, the lock plate 31 moves from the locked position to the unlocked position. At this point, the output portion 32a of the connecting rod 32 abuts the operating portion 5b of the pawl 5 from the side, preventing the connecting rod 32 from moving toward the operating portion 5b. The spring 35 remains compressed. Furthermore, the lock state detection switch 18, pushed downward by the rising joint 33, switches from the on state to the off state, outputting a lock switching signal to the control unit 20.

[0049] When Figure 3 When the first pulling operation of the inner handle 8 is stopped in the state, the inner opening lever 34 rotates counterclockwise due to the elastic force, and the connecting rod 32 descends accordingly. In addition, when the connecting rod 32 descends, the lateral engagement between the output portion 32a of the connecting rod 32 and the operating portion 5b of the pawl 5 is released, and the connecting rod 32 moves in the unlocking direction due to the force of the spring 35. Figure 6 As shown, the locking plate 31 is in the unlocked position, and the output portion 32a is in the state of being aligned with the operating portion 5b of the pawl 5 in the horizontal direction of the figure, that is, in the unlocked state. Figure 6 In the state, the control unit 20 drives the locking mechanism motor 10 to lower the joint 33, and as a result, Figure 7 As shown, the locking plate 31 moves from the unlocked position to the locked position, and the locking mechanism 9 switches from the unlocked state to the locked state.

[0050] It should be noted that the timing for performing the electric child-safety switch operation, in which the control unit 20 drives the locking mechanism motor 10 to shift the locking plate 31 from the unlocked position to the locked position after receiving the lock switching signal, is not limited to the timing described above. For example, the operation may be performed during the first pulling operation of the inside handle 8 or after the first pulling operation of the inside handle 8 has ceased. In other words, it is preferred that the electric child-safety switch operation be performed immediately after the control unit 20 receives the lock switching signal, so that the electric child-safety switch operation can be reliably performed before the second pulling operation of the inside handle 8.

[0051] As described above, the override function is invalid in the child lock state, and the locking mechanism 9 cannot be switched from the locked state to the unlocked state by operating the inside handle 8 .

[0052] When the child lock state is reached by receiving a child lock signal from the child lock selector switch 17, the override mechanism 11 moves the lock plate 31 from the locked position to the unlocked position, thereby receiving a lock switch signal from the lock state detection switch 18. The control unit 20 then drives the lock mechanism motor 10 to move the lock plate 31 from the unlocked position to the locked position. This control of the lock mechanism motor 10 by the control unit 20 eliminates the need for a dedicated motor for the child lock mechanism. This allows the child lock mechanism of the latch device 1 to be motorized while minimizing the cost associated with an increase in the number of components and structural complexity.

[0053] When receiving a lock switching signal from the lock state detection switch 18 in the child lock state, the control unit 20 causes the alarm generating unit 21 to generate an alarm. The alarm generating unit 21 generates an alarm, which notifies a passenger who attempts to operate the inside handle 8 to use the override mechanism 11 that the override is not possible due to the child lock state. In other words, the passenger who attempts to operate the inside handle 8 to use the override mechanism 11 can be informed that the latch device 1 is operating normally because the latch device 1 is in the child lock state and that the latch device 1 is unable to override the inside handle 8 even if the inside handle 8 is operated.

[0054] As described above, the override mechanism 11 is a double-acting override mechanism that, when the child lock is released, switches the lock plate 31 from the locked position (locked state) to the unlocked position (unlocked state) and releases the engagement of the pawl 5 with the shift fork 4 by operating the inside handle 8 twice. Furthermore, a certain amount of time must exist between the first and second operations of the inside handle 8. Therefore, when the child lock is engaged, when the override mechanism 11 moves the lock plate 31 from the locked position to the unlocked position by the first operation of the inside handle 8, the control unit 20, receiving the lock switching signal from the lock state detection switch 18, drives the lock mechanism motor 10 to move the lock plate 31 from the unlocked position to the locked position before the second operation of the inside handle 8. In other words, because the override mechanism 11 is a double-acting override mechanism, the child lock operated by the lock mechanism drive motor 10 can function reliably.

[0055] When an emergency signal is received from the emergency sensor 19, even if a lock switching signal is received from the lock state detection switch 18 in the child lock state, the control unit 20 does not drive the locking mechanism motor 10 and maintains the locking mechanism 9 in the unlocked state. This ensures that the door can be released by operating the inside handle 8 in an emergency, thereby improving safety.

[0056] It should be noted that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit and scope of the present invention.

Claims

1. A door latch device comprising: The fork holds the firing pin in an engaging / disengaging manner; a ratchet pawl capable of engaging with or disengaging from the shift fork, and capable of engaging with the shift fork to maintain the engagement state of the shift fork and the striker; The internal opening lever can rotate in conjunction with the operation of the inner handle; a locking member movable between an unlocked position and a locked position; a locking mechanism motor capable of switching the locking member to either the unlocked position or the locked position; a locking member position detecting unit that directly or indirectly detects movement of the locking member from the locking position to the unlocking position and outputs a locking switching signal; a connecting rod that works in conjunction with the locking member, and is capable of transmitting the rotational force of the internal opening rod to the pawl to release the engagement between the pawl and the shift fork when the locking member is in the unlocked position, and is unable to transmit the rotational force of the internal opening rod to the pawl when the locking member is in the locked position; an override mechanism capable of shifting the locking member from the locked position to the unlocked position by rotation of the interior opening lever; a child lock operation accepting unit for accepting a selection operation of using or not using the child lock mechanism, outputting a child lock signal if the accepted selection operation is to use the child lock mechanism, and outputting a child lock release signal if the accepted selection operation is to not use the child lock mechanism; and a control unit capable of receiving the child lock signal and the child lock release signal from the child lock operation receiving unit, and capable of receiving the lock switching signal from the lock member position detecting unit, In the child lock state in which the child lock signal is received from the child lock operation accepting unit, when the lock switching signal is received from the lock member position detecting unit, the control unit drives the lock mechanism motor to move the lock member from the locked position to the unlocked position.

2. The door latch device according to claim 1, wherein: Equipped with an alarm generating unit, The control unit causes the alarm generating unit to generate an alarm when the lock switching signal is received from the lock member position detecting unit in the child lock state in which the child lock signal is received from the child lock operation accepting unit.

3. The door latch device according to claim 1, wherein: The override mechanism includes an override operation portion capable of operating the locking member from the locked position to the unlocked position by rotating the inside open lever. When the locking member is in the locked position, the locking member is moved from the locked position to the unlocked position by the override operation portion through a first operation of the inside handle. After the first operation, if the control unit is in a child lock release state where the control unit receives the child lock release signal from the child lock operation receiving unit, the rotational force of the internal opening rod is transmitted to the pawl through the second operation of the inner handle, and the engagement between the pawl and the fork is released.

4. The door latch device according to claim 1, wherein: An emergency sensor is provided for detecting an emergency situation in which the engagement of the pawl with respect to the shift fork needs to be released by operating the inner handle, and outputting an emergency signal. When the emergency signal is received, the control unit does not drive the locking mechanism motor even if the lock switching signal is received from the locking member position detection unit in the child lock state.

Images