Electronic door lock with clutch

Abstract

We provide an electronic door lock with a clutch that simplifies locking and unlocking operations while reducing power consumption. [Solution] The outer lock has a cylinder 30 having a tail rack 31 attached to the front knob assembly, the tail rack 31 is rotatable relative to the cylinder 30 and can be inserted into the lock body, the tail rack 31 is connected to a clutch 40 and is rotatable together with the clutch 40 and is also rotatable relative to the front knob assembly, a motor clutch device driven by electricity is provided on the front shell to connect the front knob assembly and the clutch 40, when the electronic door lock is unlocked the protrusion 41 of the clutch is located within the rotation range of the boss of the front knob assembly, and when locked the door the protrusion 41 is located away from the rotation range of the boss.

Description

Technical Field

[0001] The present invention relates to an electronic door lock with a clutch.

Background Art

[0002] An electronic door lock usually consists of an inner lock and an outer lock, etc. The inner lock and the outer lock are respectively arranged on both sides of the door body, and a lock body that matches the inner lock and the outer lock is attached to the door body.

[0003] In some electronic door locks, the outer lock is equipped with a motor clutch device, a cylinder, and a rotatable thumb turn. When the control system of the electronic door lock receives correct NFC, password, fingerprint, or other signals, the control system sends a control signal to the motor clutch device to make the motor clutch device run in the forward direction, thereby connecting the lock body to the thumb turn. At this time, the lock can be unlocked by rotating the thumb turn. Similarly, when locking the electronic door lock, a control signal is sent to the motor clutch device to make the motor clutch device run in the forward direction, and the motor clutch device is made to run in the forward direction, thereby connecting the lock body to the thumb turn. At this time, it can be locked by rotating the thumb turn. After the motor clutch device operates to release the connection between the lock body and the thumb turn, it automatically reverses the operation and returns to the original state (is reset).

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the above-mentioned conventional structure, since the motor clutch device needs to operate by being powered on from the power source during locking and unlocking, the power consumption of the electronic door lock is large. For this reason, the battery life of the electronic door lock is shortened, and the battery replacement frequency becomes high. Furthermore, if the electronic door lock malfunctions or experiences power depletion, the motor clutch mechanism cannot be operated, preventing the lock body and thumbturn from being connected. As a result, locking and unlocking cannot be performed by rotating the thumbturn, and the user must use a key to lock and unlock the door, making the operation cumbersome.

[0005] This invention has been made in view of the above circumstances, and aims to provide an electronic door lock with a clutch that simplifies locking and unlocking operations and reduces power consumption. [Means for solving the problem]

[0006] To solve the aforementioned problems, the electronic door lock with a clutch of the present invention is Equipped with an outer lock, The outer lock comprises a front shell and a front knob assembly rotatably inserted into the front shell. A rotation limiting device is provided between the front shell and the front knob assembly to limit the rotation angle of the front knob assembly relative to the front shell. A cylinder having a tail rack is attached to the front knob assembly, and the tail rack is rotatable relative to the cylinder and can be inserted into the lock body. The tail rack is connected to a clutch, and the tail rack and the clutch are rotatable together, and the clutch is rotatably mounted relative to the front knob assembly. A motor clutch device is provided on the front shell, and the motor clutch device is powered by electricity and can connect the front knob assembly and the clutch. The clutch is provided with a protrusion, and the front knob assembly is provided with a boss. When the electronic door lock is unlocked, the protrusion is located within the rotational range of the boss, and when the electronic door lock is locked, the protrusion is located outside the rotational range of the boss. It is characterized by the following:

[0007] In the above configuration of the present invention, the protrusions may be provided in pairs on both sides of the clutch.

[0008] Furthermore, in the above configuration of the present invention, the rotation limiting device may include a first stop portion, a second stop portion, and a locking portion, wherein the first stop portion is provided on the front knob assembly, the second stop portion and the locking portion are provided on the front shell, the second stop portion is arranged on both sides of the locking portion, the first stop portion can contact the second stop portion when the front knob assembly rotates, and a first biasing member is provided between the first stop portion and the locking portion to return the front knob assembly to its original position.

[0009] Furthermore, in the above configuration of the present invention, the front knob assembly may comprise a front knob cover, a fixing piece, and a rotating piece, wherein the front knob cover and the rotating piece are positioned on the front and rear sides of the front shell, respectively, the fixing piece is rotatably inserted into the front shell, the fixing piece is fixed to the front knob cover and the rotating piece, a housing portion is formed in the front knob cover and the fixing piece, the cylinder is inserted and positioned in the housing portion, and the tail rack extends rearward from the rotating piece.

[0010] Furthermore, in the above configuration of the present invention, a first mounting groove may be provided on the rear side of the rotating piece, the clutch may be rotatably inserted into this first mounting groove, and the tail rack may be inserted into and connected to the clutch.

[0011] Furthermore, in the above configuration of the present invention, the motor clutch device comprises a motor clutch, a pin, and a biasing member, wherein the motor clutch is provided on the front shell, the motor clutch is provided with a pressing portion, the pin is inserted into the front knob assembly so as to be reciprocally movable and is positioned between the pressing portion and the clutch, the clutch is provided with a clutch groove, the pin is inserted into the clutch groove, the biasing member is provided between the pin and the front knob assembly, the motor clutch moves the pin toward the clutch by the pressing portion, and the biasing member moves the pin away from the clutch.

[0012] Furthermore, in the above configuration of the present invention, the clutch groove may be provided in two locations, on both sides of the clutch.

[0013] Furthermore, in the above configuration of the present invention, a first cover body may be provided on the rear side of the front shell, and a cylindrical shell and column rods may be provided on the rear side of the first cover body, with the column rods located inside the cylindrical shell and at least two of them arranged in parallel.

[0014] Furthermore, in the above configuration of the present invention, an inner lock may be further provided, the inner lock comprising an inner shell and an inner knob assembly rotatably mounted on the inner shell, and the inner knob assembly comprising a transmission jack into which the tail rack is inserted.

[0015] Furthermore, in the above configuration of the present invention, the inner knob assembly further comprises an inner knob cover, a limiting member, and a retaining ring, wherein the inner knob cover and the limiting member are each arranged on both sides of the inner shell, the inner knob cover comprises a shaft portion rotatably provided on the inner shell and a mounting portion fitted into the limiting member, the retaining ring is attached to the outer circumferential surface of the mounting portion on the rear side of the limiting member, and an inner rotation limiting device is provided between the limiting member and the inner shell to limit the rotation angle of the inner knob assembly.

[0016] Furthermore, in the above configuration of the present invention, the inner rotation limiting device may include a first limiting column, a second limiting column, a third limiting column, a limiting screw, and a second torsion spring, wherein the first limiting column and the second limiting column are provided on the inner shell at intervals, the third limiting column is provided on the limiting member, the limiting screw is provided on the inner shell so that the limiting member abuts against it, and both ends of the second torsion spring are attached to the first limiting column and the third limiting column, respectively.

[0017] Furthermore, in the above configuration of the present invention, the inner rotation limiting device may be provided in pairs on both sides of the mounting portion. [Effects of the Invention]

[0018] According to the present invention, by inserting a key into a cylinder, an electronic door lock can be locked and unlocked. Further, when the electronic door lock can be driven by power, a front knob assembly is connected to a clutch by a motor clutch device, and the electronic door lock can be locked and unlocked by turning the front knob assembly. Further, even when power is not supplied to the motor clutch device, the door can be locked by turning the front knob assembly, so there is no need to insert a key to lock the door, and the locking operation becomes simple. Further, since the motor clutch device does not need to be operated by power when locking the door, power consumption can be reduced, and the door can be easily locked even when the electronic door lock fails or the power supply stops due to battery depletion or the like.

Brief Description of the Drawings

[0019] [Figure 1] It is a view showing an electronic door lock with a clutch according to an embodiment of the present invention, and is a perspective view of an outer lock. [Figure 2] It is a perspective view of the outer lock. [Figure 3] It is a cross-sectional view of the outer lock of the same. [Figure 4] It is an exploded perspective view of the outer lock of the same. [Figure 5] It is an exploded perspective view of the outer lock of the same. [Figure 6] It is a perspective view showing a part of the outer lock in cross section. [Figure 7] It is a perspective view of the inner lock of the same. [Figure 8] It is a cross-sectional view of the inner lock of the same. [Figure 9] It is an exploded perspective view of the inner lock of the same. [Figure 10] It is a rear view of the inner lock of the same.

Embodiments for Carrying Out the Invention

[0020] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Furthermore, the function of the drawings is to supplement the explanation of the present invention with diagrams, thereby enabling people to intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but not to be understood as a limitation of the scope of protection of the present invention. Furthermore, in the description of the present invention, directions or positional relationships such as up, down, front, back, left, and right should be understood to be based on the directions or positional relationships shown in the accompanying drawings, and are solely for the convenience of simplifying the description of the present invention. This does not indicate or imply that the devices or elements mentioned must have a specific directional orientation, or must be constructed and operated in a specific direction, and therefore cannot be construed as a limitation on the present invention. Furthermore, in the description of the present invention, if the descriptions of the first, second, third, etc. are solely for the purpose of distinguishing technical features, they cannot be understood as suggesting or implying relative importance, the number of technical features shown, or the order in which the technical features shown are shown. Furthermore, in the description of the present invention, unless otherwise explicitly limited, terms such as installation, arrangement, connection, and linking should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of these terms in the present invention in combination with the specific content of the technical solution.

[0021] As shown in Figures 1 to 10, the electronic door lock with clutch according to an embodiment of the present invention comprises an outer lock and an inner lock. The outer lock is installed on the outside of the door body, the inner lock is installed on the inside of the door body, and the lock body is installed between the outer lock and the inner lock of the door body.

[0022] The outer lock comprises a front shell 10, a front knob assembly 20, a cylinder 30, a clutch 40, and a motor clutch device 50.

[0023] The front shell 10 is fixed to the outside of the door body. The front knob assembly 20 is rotatably inserted into the front shell 10. The front knob assembly 20 is provided with a boss (projection) 231. A rotation limiting device is also provided between the front shell 10 and the front knob assembly 20. This rotation limiting device has the function of limiting the rotation angle of the front knob assembly 20 relative to the front shell 10, and also functions to limit the rotation of the boss 231 on the front knob assembly 20 to within a certain range.

[0024] The cylinder 30 is mounted on the front knob assembly 20, and a tail rack 31 is provided at the tail end of the cylinder 30. The tail rack 31 is used to connect to the lock body. The tail rack 31 is rotatable relative to the cylinder 30.

[0025] The clutch 40 is connected to the tail rack 31 by being inserted into it, thereby allowing it to rotate integrally with the tail rack 31. The clutch 40 is rotatable relative to the front knob assembly 20. The side wall of the clutch 40 is provided with a projection 41 that protrudes radially outward, and this projection 41 is capable of contacting the boss 231. When the electronic door lock is unlocked, the projection 41 is positioned within the rotational range of the boss 231. When the electronic door lock is locked, the projection 41 moves away from the rotational range of the boss 231.

[0026] The motor clutch device 50 is installed on the front shell 10. This motor clutch device 50 is provided to connect the front knob assembly 20 and the clutch 40 so that they can rotate together. The motor clutch device 50 is powered by electricity.

[0027] In this embodiment, the rotation limiting device comprises a first stop portion 111, a second stop portion 112, and a locking portion 113. The first stop portion 111 is provided on the front knob assembly 20 (rotating piece 23), and the second stop portion 112 and the locking portion 113 are both provided on the front shell 10, with two second stop portions 112 positioned on either side of the locking portion 113. The front shell 10 is provided with a roughly cylindrical peripheral edge portion 12 positioned around the front knob assembly 20, and a first torsion spring (first biasing member) 114 is wound around the outside of the peripheral edge portion 12. The left end of the torsion arm of the first torsion spring 114 is locked to the right side of the locking portion 113, and the right end of the torsion arm of the first torsion spring is locked to the left side of the first stop portion 111.

[0028] When the front knob assembly 20 rotates, the first stopper 111 comes into contact with the second stopper 112, thereby limiting the rotation angle of the front knob assembly 20, and at this time the boss 231 rotates within a certain angular range. After rotating the front knob assembly 20, the restoring force (biasing force) of the first torsion spring 114 can be used to return the front knob assembly 20 to its original position (the front knob assembly 20 in this state is shown in Figure 4).

[0029] The front knob assembly 20 comprises a front knob cover 21, a fixing piece 22, and a rotating piece 23, the front knob cover 21 and the rotating piece 23 being positioned on opposite sides of the front shell 10, the fixing piece 22 being rotatably inserted into the front shell 10, and the fixing piece 22 being fixed and connected to the front knob cover 21 and the rotating piece 23 by screws, the front knob cover 21 and the fixing piece 22 having a housing portion, the cylinder 30 being inserted and positioned within this housing portion, and the tail rack 31 extending behind the rotating piece 23.

[0030] A first mounting groove 232 is provided on the rear side of the rotating piece 23, the clutch 40 is rotatably inserted into this first mounting groove 232, and the tail rack 31 is inserted into the clutch 40 to connect them. This structure allows the clutch 40 to be rotatably mounted on the front knob assembly 20.

[0031] The motor clutch device 50 comprises a motor clutch 51, a pin 52, and a spring (biasing member) 521. The motor clutch 51 is mounted on the front shell 10, and a pressing band (pressing portion) 511 is provided at the output end of the motor clutch 51. The pin 52 is slidably (reciprocally) inserted into the front knob assembly 20 and is located between the clutch 40 and the pressing band 511. A clutch groove 42 is provided in the side wall of the clutch 40, into which the pin 52 is inserted. The spring 521 is positioned between the pin 52 and the front knob assembly 20. A motor clutch 51 is used to move the pin 52 toward the clutch 40 by a pressing band 511, and a spring 521 is used to move the pin 52 toward the clutch 40.

[0032] More specifically, a second mounting groove 233 is formed in the rotating part 23, with both ends of the second mounting groove 233 passing through, and the pin 52 and spring 521 are positioned in the second mounting groove 233, which is covered by a limiting cover 24 to prevent the pin 52 and spring 521 from coming out of their designated positions.

[0033] When the electronic door lock is locked, the clutch groove 42 is facing the pin 52, and the motor clutch 51 is moved backward and returned to its original position (reset), so that the pin 52 is away from the clutch groove 42. When the electronic door lock is locked, power is supplied to the motor clutch 51 (a locking control signal is sent), causing the motor clutch 51 to move forward. Consequently, the pressing band 511 moves forward, and the pressing band 511 pushes the pin 52, moving the pin 52 toward the clutch 40, and inserting the pin 52 into the clutch groove 42. As a result, the front knob assembly 20 is connected to the clutch 40, and the two cannot rotate relative to each other. By rotating the front knob assembly 20, the lock body is activated by the tail rack 31 and the door can be locked.

[0034] The aforementioned protrusions 41 and clutch grooves 42 are each provided in pairs on both sides of the clutch 40. This structure allows the lock body to be installed in either the left-right or right-handed direction, and can be attached to doors that open or close on either the left or right side.

[0035] The rear side of the front shell 10 is connected to the first cover body 13 by screws, and the rear side of the first cover body 13 is provided with a cylindrical shell 131 and column rods 132. The column rods 132 are located inside the cylindrical shell 131, and at least two of them are arranged in parallel. The cylindrical shell 131 is used to insert into the door opening of the door body, the lock body is supported by the insertion of the column rod 132, and the inner lock is connected and secured to the column rod 132 by screws, thereby precisely mounting the electronic door lock to the door body. The clutch 40 can also be rotatably mounted on the front shell 10 or the first cover body 13.

[0036] The inner lock comprises an inner shell 60 and an inner knob assembly 70 positioned within the inner shell 60. The second cover body 61 is secured to the inner shell 60 by screws. The inner knob assembly 70 is provided with a transmission jack 711 in a position corresponding to the tail rack 31, and during assembly, the tail rack 31 passes through the lock body and is inserted into the transmission jack 711.

[0037] The inner knob assembly 70 comprises an inner knob cover 71 and a limiting member 72, with the inner knob cover 71 and the limiting member 72 positioned on opposite sides of the inner shell 60. The inner knob cover 71 includes a shaft portion 712 that is rotatably inserted into the inner shell 60 and a shaft-shaped mounting portion 713 that fits into the limiting member 72. The cross-section of the mounting portion 713 is non-circular, such as a track-like or prismatic shape, and restricts relative rotation between the inner knob cover 71 and the limiting member 72. A transmission jack 711 extends from the end face of the mounting portion 713 along the axis of the inner knob cover 71. A retaining ring 73 is attached to the outer circumferential surface of the mounting portion 713 on the rear side of the limiting member 72. This structure allows the inner knob assembly 70 to be rotatably installed on the inner shell 60.

[0038] The inner rotation limiting device is provided between the limiting member 72 and the inner shell 60. The inner rotation limiting device limits the rotation angle of the inner knob assembly. This inner rotation limiting device comprises a first limiting column 81, a second limiting column 82, a third limiting column 83, a limiting screw 84, and a second torsion spring 85. The first limiting column 81 and the second limiting column 82 are provided in the inner shell 60 with a gap between them, the third limiting column 83 is provided in the limiting member 72, the limiting screw 84 is provided in the inner shell 60 and the side surface of the second limiting column 82 is in contact with it, and both ends of the second torsion spring 85 are fixed to the first limiting column 81 and the third limiting column 83, respectively. More specifically, the ends of the torsion arms of the second torsion spring 85 are each formed into annular shapes, one end of the torsion arm of the second torsion spring 85 is fitted into the first limiting column 81, the other end of the torsion arm of the second torsion spring 85 is fitted into the third limiting column 83, and screws are installed on the upper parts of the first limiting column 81 and the third limiting column 83 respectively to restrict the detachment of the torsion arms.

[0039] Two inner rotation limiting devices are arranged side by side on both sides of the shaft portion 712. The first limiting column 81, the second limiting column 82, the third limiting column 83, the limiting screw 84, and the second torsion spring 85 are each arranged side by side on both sides of the shaft portion 712. Two limiting screws 84 are arranged side by side on both sides of the shaft portion 712, and the two limiting screws 84 are brought into contact with both sides of the control member 72 simultaneously to limit its rotation. During installation, one of the limiting screws 84 and the corresponding second torsion spring 85 are removed according to the direction in which the door is opened, allowing the inner knob assembly 70 to rotate within a certain range.

[0040] In the electronic door lock with a clutch as described above, when no key is inserted, the tail rack 31 can rotate relative to the cylinder 30. When a key is inserted, the tail rack 31 is connected to the cylinder 30, and the key, tail rack 31, and cylinder 30 can rotate together. The tail rack 31 is then inserted into the clutch 40 and the lock body, and when the key is turned, the tail rack 31 rotates, which in turn causes the clutch 40 to rotate together with the tail rack 31, and activates the lock body, allowing it to be unlocked or locked.

[0041] Figure 4 shows that the electronic door lock is locked and the motor clutch device 50 is in a reset state (returned to its original position). At this time, the motor clutch device 50 does not connect the clutch 40 to the front knob assembly 20, and therefore the clutch 40 cannot be rotated together with the front knob assembly 20 by rotating the front knob assembly 20. In addition, the protrusion 41 of the clutch 40 is located away from the rotation range of the boss 231, so even if the front knob assembly 20 is rotated, the protrusion 41 does not come into contact with the boss 231, and therefore the clutch 40 cannot be rotated. In other words, even if the front knob assembly 20 is rotated, the first stop portion 111 of the front knob assembly 20 (rotating piece 23) comes into contact with the second stop portion 112 of the front shell 10 before the boss 231 comes into contact with the protrusion 41 of the clutch 40, and therefore the clutch 40 cannot be rotated. Thus, when the electronic door lock is locked and the motor clutch device 50 is in a reset state, even if the front knob assembly 20 is rotated, the clutch 40 and the tail rack 31 connected to the clutch 40 cannot be rotated, so the lock body cannot be operated and the door cannot be unlocked. In this case, as described above, the lock can be unlocked by inserting the key into the cylinder 30.

[0042] When the electronic door lock can be powered, the electronic door lock control system controls it and powers the motor clutch 51 (sends an unlocking control signal). This causes the motor clutch 51 to move forward, and consequently the pressing band 511 to move forward. The pressing band 511 pushes the pin 52, moving the pin 52 toward the clutch 40, and inserting the pin 52 into the clutch groove 42. As a result, the front knob assembly 20 is connected to the clutch 40, and the two cannot rotate relative to each other. By rotating the front knob assembly 20, the lock body can be activated by the tail rack 31 and unlocked. When the front knob assembly 20 is rotated by a certain angle, the first stop portion 111 of the front knob assembly 20 (rotating piece 23) comes into contact with the second stop portion 112 of the front shell 10 located in the direction of rotation, so it cannot rotate any further. In this embodiment, the rotatable angle of the front knob assembly 20 is approximately 90 degrees.

[0043] After unlocking, the motor clutch device 50 is moved backward and reset. As a result, the biasing force of the spring 521 causes the pin 52 to move away from the clutch 40, thereby releasing the connection between the clutch 40 and the front knob assembly 20, and the clutch 40 and the front knob assembly 20 return to a state where they can rotate relative to each other. As a result, the front knob assembly 20 rotates in the opposite direction to the direction of rotation due to the restoring force of the first torsion spring 114, returning to the position shown in Figure 4. On the other hand, the tail rack 31 and clutch 40 are rotated by a certain angle relative to the state shown in Figure 4, and at this time the protrusion 41 of the clutch 40 is located within the rotation range of the boss 231. In this embodiment, the tail rack 31 and clutch 40 are rotated by approximately 90 degrees and are located on the upper side in Figure 4. In this embodiment, the rotation range of the boss 231 is the rotation range until the first stop part 111 contacts the left and right second stop parts 112, which is a range slightly narrower than the approximately 180 degrees on the upper side in Figure 4. In this situation, even if the electronic door lock cannot be powered, it can be locked by rotating the front knob assembly 20. That is, when the front knob assembly 20 is rotated in the opposite direction to when it is unlocked, the boss 231 rotates in the opposite direction as the front knob assembly 20 rotates, contacting the projection 41, and the boss 231 pushes the projection 41 and rotates the clutch 40 together with it. This allows the tail rack 31 connected to the clutch 40 to rotate in the opposite direction, and the tail rack 31 activates the lock body and locks the door.

[0044] After locking, the front knob assembly 20 rotates in the opposite direction to the direction of rotation due to the restoring force of the first torsion spring 114, returning to the position shown in Figure 4. In this way, after locking, it returns to the state shown in Figure 4, so as described above, even if you try to unlock it by rotating the front knob assembly 20, you cannot rotate the clutch 40, and therefore you cannot unlock it.

[0045] As explained above, locking and unlocking the electronic door lock can be performed by inserting a key into the cylinder 30. Furthermore, if power can be supplied to the electronic door lock, the motor clutch device 50 can be activated to connect with the front knob assembly 20 and the clutch 40, and the door can be locked and unlocked by rotating the front knob assembly 20.

[0046] Furthermore, if power cannot be supplied to the electronic door lock and the motor clutch device 50 cannot be operated, the motor clutch device 50 is in a reset state (returned to its original position), and the door can be locked by rotating the front knob assembly 20. This eliminates the need to insert a key to lock the door, making it convenient for the user. It also eliminates the need to operate the power supply of the motor clutch device 50 when locking, reducing power consumption, and allows for easy locking even if the electronic door lock malfunctions or the power is cut off.

[0047] Here, under conditions where the electronic door lock can be driven by a power source, when it needs to be unlocked, after receiving the correct NFC, password, fingerprint, and other signals through the control system, the control system can drive the motor clutch device 50 and unlock the door, provided that security is ensured.

[0048] In the embodiments of the present invention, the functions of the motor clutch 51 and cylinder 30 are all possessed by existing products on the market, and the motor clutch 51 and cylinder 30 having the above functions can be obtained by outsourcing. Those skilled in the art will understand the structure, so it will not be described in detail here. Furthermore, while embodiments of the present invention are described above in conjunction with the accompanying drawings, the present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the knowledge possessed by persons skilled in the art, without departing from the purpose of the present invention. [Explanation of symbols]

[0049] 10 Front Shell 20 Front knob assembly 231 Boss 30 Rock 31 Tail Rack 40 Clutch 41 Convex part 50 Motor clutch device

Claims

1. Equipped with an outer lock, The outer lock comprises a front shell and a front knob assembly rotatably inserted into the front shell. A rotation limiting device is provided between the front shell and the front knob assembly to limit the rotation angle of the front knob assembly relative to the front shell. A cylinder having a tail rack is attached to the front knob assembly, and the tail rack is rotatable relative to the cylinder and can be inserted into the lock body. The tail rack is connected to a clutch, and the tail rack and the clutch are rotatable together, and the clutch is rotatably mounted relative to the front knob assembly. A motor clutch device is provided on the front shell, and the motor clutch device is powered by electricity and can connect the front knob assembly and the clutch. The clutch is provided with a protrusion, and the front knob assembly is provided with a boss. When the electronic door lock is unlocked, the protrusion is located within the rotational range of the boss, and when the electronic door lock is locked, the protrusion is located outside the rotational range of the boss. An electronic door lock with a clutch, characterized by its features.

2. The electronic door lock with a clutch according to claim 1, characterized in that the aforementioned protrusions are provided in pairs on both sides of the clutch.

3. The rotation limiting device comprises a first stop portion, a second stop portion, and a locking portion, the first stop portion being provided on the front knob assembly, the second stop portion and the locking portion being provided on the front shell, the second stop portion being positioned on both sides of the locking portion, the first stop portion being able to contact the second stop portion when the front knob assembly rotates, and a first biasing member for returning the front knob assembly to its original position is provided between the first stop portion and the locking portion, characterized in that the electronic door lock with a clutch according to claim 1.

4. The front knob assembly comprises a front knob cover, a fixing piece, and a rotating piece, wherein the front knob cover and the rotating piece are positioned on the front and rear sides of the front shell, respectively, the fixing piece is rotatably inserted into the front shell, the fixing piece is fixed to the front knob cover and the rotating piece, a housing portion is formed in the front knob cover and the fixing piece, the cylinder is inserted into the housing portion, and the tail rack extends rearward from the rotating piece, as described in claim 1.

5. The electronic door lock with a clutch according to claim 5, characterized in that a first mounting groove is provided on the rear side of the rotating piece, the clutch is rotatably inserted into the first mounting groove, and the tail rack is inserted into and connected to the clutch.

6. The motor clutch device comprises a motor clutch, a pin, and a biasing member, wherein the motor clutch is provided on the front shell, the motor clutch is provided with a pressing portion, the pin is inserted into the front knob assembly so as to be reciprocally movable and is positioned between the pressing portion and the clutch, the clutch is provided with a clutch groove, the pin is inserted into the clutch groove, the biasing member is provided between the pin and the front knob assembly, the motor clutch moves the pin toward the clutch by the pressing portion, and the biasing member moves the pin away from the clutch, as described in claim 1.

7. The electronic door lock with a clutch according to claim 6, characterized in that two clutch grooves are provided on both sides of the clutch.

8. The electronic door lock with a clutch according to claim 1, characterized in that a first cover body is provided on the rear side of the front shell, a cylindrical shell and a column rod are provided on the rear side of the first cover body, the column rod is located inside the cylindrical shell and at least two are arranged in parallel.

9. The electronic door lock with clutch according to claim 1, further comprising an inner lock, the inner lock comprising an inner shell and an inner knob assembly rotatably mounted on the inner shell, the inner knob assembly comprising a transmission jack into which the tail rack is inserted.

10. The electronic door lock with clutch according to claim 9, wherein the inner knob assembly further comprises an inner knob cover, a limiting member, and a retaining ring, the inner knob cover and the limiting member are each arranged on both sides of the inner shell, the inner knob cover comprises a shaft portion rotatably mounted on the inner shell and a mounting portion fitted into the limiting member, the retaining ring is mounted on the outer circumferential surface of the mounting portion on the rear side of the limiting member, and an inner rotation limiting device is provided between the limiting member and the inner shell to limit the rotation angle of the inner knob assembly.

11. The inner rotation limiting device comprises a first limiting column, a second limiting column, a third limiting column, a limiting screw, and a second torsion spring, wherein the first limiting column and the second limiting column are provided on the inner shell at intervals, the third limiting column is provided on the limiting member, the limiting screw is provided on the inner shell and the limiting member abuts against it, and both ends of the second torsion spring are attached to the first limiting column and the third limiting column, respectively, as described in claim 10.

12. The electronic door lock with a clutch according to claim 11, characterized in that two of the inner rotation limiting devices are provided on both sides of the mounting portion.

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