Diameter-adjustable electric wrench

Abstract

The utility model relates to the technical field of bolt screwing, and discloses a diameter-adjustable electric wrench which comprises a shell, a telescopic mechanism and a plurality of clamping jaws, the shell is in a pistol shape, the telescopic mechanism is connected in the shell, the clamping jaws surround the periphery of the telescopic mechanism, one end of each clamping jaw extends out of the shell, and the telescopic mechanism comprises a telescopic rod and a nut. The linear reciprocating motion assembly reciprocates along the horizontal axis of the shell, the connecting rod assemblies are connected with the multiple clamping jaws in a one-to-one correspondence mode, the connecting rod assemblies convert linear motion of the linear reciprocating motion assembly into radial contraction and expansion of the clamping jaws, and a second motor is fixed in the shell. The output end of the second motor is connected with the telescopic mechanism, and the second motor drives the telescopic mechanism to rotate and further drives the multiple clamping jaws to rotate synchronously.

Description

Technical Field

[0001] The utility model relates to the technical field of bolt tightening, in particular to an electric wrench with adjustable diameter. Background Art

[0002] Bolt tightening is a critical process in fields such as mechanical assembly, steel structure engineering, wind power installation, and rail transit. Its quality directly affects the reliability and safety of the structure. Traditional manual tightening has problems such as low efficiency and poor preload consistency. Electric wrenches, with their automation, high precision, and traceability, have gradually become the core tool for modern industrial bolt connection. The output shaft of an electric wrench generally adopts a square tenon structure, which matches the standard size of the inner square of the socket. In actual application, electric wrenches are usually used in conjunction with sockets to achieve the tightening of bolts of different specifications. Bolt sockets are a replaceable accessory widely used in power and hand tools, mainly used for tightening or removing bolts. As a core component in modern assembly operations, sockets achieve rapid connection with power tools and hand tools through their standardized quick-change interfaces. Its working principle is to accurately convert mechanical energy into the tightening or removal of bolts by transmitting the rotational torque generated by the tool, thereby significantly improving work efficiency.

[0003] In the field of bolt installation, existing bolt sleeves are mostly fixed in size. When using electric wrenches to adapt to high-strength bolts of different diameters, the corresponding bolt sleeves must be manually replaced, which is extremely cumbersome and seriously affects work efficiency. Utility Model Content

[0004] In order to solve the above technical problems, the utility model provides an electric wrench with adjustable diameter.

[0005] The utility model provides an electric wrench with adjustable diameter, comprising: a housing, a telescopic mechanism and a plurality of clamping claws, wherein the housing is pistol-shaped, the telescopic mechanism is connected inside the housing, the plurality of clamping claws surround the periphery of the telescopic mechanism, and one end of the clamping claws extends out of the housing;

[0006] The telescopic mechanism includes: a linear reciprocating moving component and a plurality of connecting rod components. The linear reciprocating moving component reciprocates along the horizontal axis of the shell. The connecting rod component converts the linear motion of the linear reciprocating moving component into radial contraction and expansion of the clamping jaws.

[0007] The connecting rod assembly includes a first connecting rod, a second connecting rod, a third connecting rod and a sleeve. The first connecting rod is fixed to the inner wall of the clamping jaw. The sleeve is connected to the movable end of the linear reciprocating movable assembly. The second connecting rod is distributed circumferentially around the sleeve. The second connecting rod is connected to the first connecting rod in a one-to-one correspondence through the third connecting rod. The first end of the third connecting rod is rotatably connected to the first connecting rod, and the second end is rotatably connected to the second connecting rod.

[0008] A second motor is fixed in the shell, and an output end of the second motor is connected to the telescopic mechanism. The second motor drives the telescopic mechanism to rotate, thereby driving the multiple clamping claws to rotate synchronously.

[0009] Optionally, the linear reciprocating motion component includes: an internal threaded stud, an external threaded stud and a first motor, the internal threaded stud and the external threaded stud are engaged with each other through a threaded pair, the internal threaded stud is nested in the sleeve, and the external threaded stud is connected to the output end of the first motor.

[0010] Optionally, an inner concave structure is provided at one end of the inner thread stud extending out of the shell, and the inner concave structure is a regular hexagon.

[0011] Optionally, a limit assembly is also included, which includes: a limit connecting ring and a limit protection ring. The limit connecting ring is a regular hexagonal prism, and multiple supporting legs are distributed on the side of the limit connecting ring. The supporting legs are provided with through grooves, and multiple clamping claws are slidably connected in the through grooves one by one. The limit protection ring and the limit connecting ring are detachably connected, and the limit protection ring is sleeved on the outer periphery of the clamping claws.

[0012] Optionally, the telescopic mechanism also includes a first motor seat, the first motor seat is provided with a first cavity matching the first motor, the first motor is fixed in the first cavity, a conductive ring is fixed on the outside of the first motor seat, the first electrode sheet led out from the inside of the first motor is in sliding contact with the first side of the conductive ring, transmitting the working current of the first motor, the second electrode sheet connected to the control line is in sliding contact with the second side of the conductive ring, transmitting forward and reverse control signals and power supply.

[0013] Optionally, the shell includes a first shell and a second shell that are detachably connected, a second cavity matching the second motor is opened in the second shell, the second motor is fixed in the second cavity, and the clamping claws extend out of the first shell.

[0014] Optionally, a plurality of control buttons are connected to the vertical portion of the second shell, and the plurality of control buttons control the forward and reverse rotation and start and stop of the second motor, as well as the reciprocating movement and start and stop of the linear reciprocating motion component.

[0015] Optionally, a clamping head is fixed to one end of the multiple clamping claws extending out of the shell, the clamping head faces inward, and a tooth-shaped anti-slip pattern is provided on the clamping head.

[0016] Optionally, the linear reciprocating motion assembly can be adapted to connect connecting rod assemblies of different specifications.

[0017] The technical solution provided by the embodiment of the present invention has the following advantages over the prior art: the present invention connects the first end of the connecting rod assembly to the clamping jaw, and the second end is connected to the moving end of the linear reciprocating assembly. When the linear reciprocating assembly reciprocates in the axial direction, it will push the clamping jaw to slide radially. This linkage mechanism converts the axial movement of the connecting rod assembly into radial sliding of the clamping jaw, and multiple clamping jaws move radially synchronously, ultimately realizing the diameter-changing function of the overall structure. Through the transmission action of the connecting rod assembly, the axial linear motion is converted into radial sliding, with high mechanical efficiency and low energy loss, which is particularly suitable for scenarios that require frequent diameter changes. The connecting rod assembly cooperates with the clamping jaw to slide in coordination, ensuring the symmetry and stability of each component during the diameter change process, avoiding unbalanced loads or jamming, and realizing multi-degree-of-freedom motion in a limited space. Improve reliability under high-speed reciprocating motion. By precisely controlling the axial displacement of the linear reciprocating assembly, the radial position of the clamping jaw can be linearly adjusted. The shell not only ensures the working space of the tool head, but also effectively prevents external dust from invading the core transmission mechanism. The second motor drives the telescopic mechanism to rotate synchronously with the clamping claw, and then transmits the rotational power to the clamped bolt to realize the tightening and disassembly operations of the bolt. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of the connection between the connecting rod assembly and the linear reciprocating motion assembly provided in an embodiment of the present utility model;

[0019] Figure 2 A schematic diagram of the connections inside the housing provided by an embodiment of the present utility model;

[0020] Figure 3 A schematic structural diagram of an electric wrench with adjustable diameter provided in an embodiment of the present utility model;

[0021] Figure 4 A schematic diagram of the connection between the connecting rod assembly and the internal thread stud provided in an embodiment of the present utility model;

[0022] Figure 5 A schematic structural diagram of a position limiting connecting ring provided in an embodiment of the present utility model;

[0023] Figure 6 A schematic structural diagram of a first motor base provided in an embodiment of the present utility model;

[0024] Figure 7 A schematic diagram of the structure of the clamping jaws provided in an embodiment of the present utility model;

[0025] Figure 8 This is a schematic structural diagram of a housing provided in an embodiment of the present utility model.

[0026] Description of reference numerals:

[0027] 1. Shell; 2. Telescopic mechanism; 3. Clamping jaw; 20. Linear reciprocating motion assembly; 21. Connecting rod assembly; 4. Second motor; 210. First connecting rod; 211. Second connecting rod; 212. Third connecting rod; 213. Sleeve; 200. Internal thread stud; 201. External thread stud; 202. First motor; 2000. Concave structure; 5. Limiting assembly; 50. Limiting connecting ring; 51. Limiting protection ring; 500. Support foot; 501. Through slot; 2020. First motor seat; 2021. Conductive ring; 2022. First electrode sheet; 2023. Second electrode sheet; 10. First shell; 11. Second shell; 110. Second cavity; 6. Control button; 60. First button; 61. Second button; 62. Third button; 63. Fourth button; 30. Chuck. DETAILED DESCRIPTION

[0028] A specific embodiment of the present invention will be described in detail below with reference to the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific embodiment.

[0029] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the technical solutions of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0030] The present invention is described below through several specific embodiments. To keep the following description of the embodiments of the present invention clear and concise, detailed descriptions of known functions and components may be omitted. When any component of an embodiment of the present invention appears in more than one drawing, the component may be represented by the same reference numeral in each drawing.

[0031] like Figure 1 and Figure 2As shown, the embodiment of the present invention provides an electric wrench with adjustable diameter, comprising: a housing 1, a telescopic mechanism 2 and a plurality of clamping jaws 3, the housing 1 being pistol-shaped, the telescopic mechanism 2 being connected inside the housing 1, the plurality of clamping jaws 3 being surrounded by the periphery of the telescopic mechanism 2, and one end of which protrudes outside the housing 1; the telescopic mechanism 2 comprising: a linear reciprocating moving assembly 20 and a plurality of connecting rod assemblies 21, the linear reciprocating moving assembly 20 reciprocating along the horizontal axis of the housing 1, the connecting rod assembly 21 converting the linear motion of the linear reciprocating moving assembly 20 into radial contraction and expansion of the clamping jaws 3; the connecting rod assembly 21 comprising a first connecting rod 210, a second connecting rod 211, The third connecting rod 212 and the sleeve 213, the inner wall of the clamping jaw 3 is fixed with the first connecting rod 210, the sleeve 213 is connected to the moving end of the linear reciprocating moving component 20, the sleeve 213 is circumferentially distributed with the second connecting rod 211, the second connecting rod 211 is connected to the first connecting rod 210 one-to-one through the third connecting rod 212, the first end of the third connecting rod 212 is rotatably connected to the first connecting rod 210, and the second end is rotatably connected to the second connecting rod 211; a second motor 4 is fixed in the shell 1, and the output end of the second motor 4 is connected to the telescopic mechanism 2, the second motor 4 drives the telescopic mechanism 2 to rotate, and then drives multiple clamping jaws 3 to rotate synchronously.

[0032] The first end of the connecting rod assembly 21 is connected to the clamping jaw 3, and the second end is connected to the moving end of the linear reciprocating assembly 20. When the linear reciprocating assembly 20 reciprocates in the axial direction, it pushes the clamping jaw 3 to slide radially. This linkage mechanism converts the axial movement of the connecting rod assembly 21 into radial sliding of the clamping jaw 3. Multiple clamping jaws 3 move radially synchronously, ultimately realizing the diameter-changing function of the overall structure. Through the transmission action of the connecting rod assembly 21, the axial linear motion is converted into radial sliding, with high mechanical efficiency and low energy loss, which is particularly suitable for scenarios that require frequent diameter changes. The connecting rod assembly 21 cooperates with the clamping jaw 3 to slide in coordination, ensuring the symmetry and stability of each component during the diameter change process, avoiding unbalanced loading or jamming, and realizing multi-degree-of-freedom motion in a limited space. Improve reliability under high-speed reciprocating motion. By precisely controlling the axial displacement of the linear reciprocating assembly 20, the radial position of the clamping jaw 3 can be linearly adjusted. The housing 1 ensures a comfortable working space for the tool head while effectively preventing external dust from intruding into the core transmission mechanism. The second motor 4 drives the telescopic mechanism 2 and the jaws 3 to rotate synchronously, thereby transmitting the rotational force to the clamped bolt, enabling bolt tightening and removal operations. The variable diameter range can be expanded by modifying the connecting rod assembly 21 without changing the core drive mechanism, facilitating customized design. Multiple second connecting rods 211 are circumferentially distributed around the sleeve 213. When the reciprocating assembly reciprocates axially, the variable diameter assembly and its second connecting rods 211 undergo synchronous axial movement. Because each third connecting rod 212 is rotationally connected to the first connecting rod 210 of the jaw 3 and its second end to the second connecting rod 211 of the variable diameter assembly, the third connecting ring pushes the jaws 3 to slide radially as the second connecting rod 211 moves axially. This linkage mechanism converts the axial movement of the variable diameter assembly into radial sliding of the jaws 3 along the stop ring 50. The synchronized radial movement of multiple jaws 3 ultimately achieves the variable diameter function of the entire structure. Through the transmission effect of the third connecting rod 212, the axial linear motion is converted into radial sliding. The double-end rotation design of the third connecting rod 212 can adapt to the change of the motion angle and reduce joint wear.

[0033] Optional, reference Figure 1 and Figure 4 The linear reciprocating motion component 20 includes: an internal threaded stud 200, an external threaded stud 201 and a first motor 202. The internal threaded stud 200 and the external threaded stud 201 are engaged with each other through a threaded pair. The internal threaded stud 200 is nested in the sleeve 213, and the external threaded stud 201 is connected to the output end of the first motor 202.

[0034] The linear reciprocating motion component 20 adopts a threaded transmission mechanism, which is composed of an internal threaded stud 200 and an external threaded stud 201 that are meshed with each other through a threaded pair. The external threaded stud 201 is directly connected to the output shaft of the first motor 202. When the motor is running, it drives the external threaded stud 201 to rotate, and the meshing action of the threaded pair converts the rotational motion into the axial displacement of the internal threaded stud 200. The internal threaded stud 200 is nested in the through hole of the sleeve 213, and its axial motion drives the sleeve 213 to move synchronously, causing the second connecting rod 211 on the fixed sleeve 213 to produce axial displacement. This displacement is transmitted to the first connecting rod 210 of the clamping jaw 3 through the third connecting rod 212, and then the axial motion is converted into radial sliding of the clamping jaw 3, realizing synchronous diameter adjustment of multiple clamping jaws 3. The mechanism adopts a threaded pair design to ensure smooth and reliable transmission, can ensure motion accuracy and prevent deflection, and make the diameter reduction process stable and symmetrical.

[0035] Optional, reference Figure 4 The inner thread stud 200 extends out of the housing 1 and is provided with an inner concave structure 2000, which is a regular hexagon.

[0036] The internal thread stud 200 has a regular hexagonal concave structure 2000 of fixed size. When encountering a bolt that matches the size of the concave structure 2000, the bolt head can be directly embedded in the concave structure 2000 for tightening. This adds a bolt adaptation tightening method to the original variable diameter range, thereby expanding the bolt adaptation range.

[0037] Optional, reference Figure 2 and Figure 5 , and also includes a limit component 5, which includes: a limit connecting ring 50 and a limit protection ring 51. The limit connecting ring 50 is a regular hexagonal prism. A plurality of supporting legs 500 are distributed on the side of the limit connecting ring 50. A through groove 501 is opened on the supporting legs 500. A plurality of clamping jaws 3 are slidably connected in the through groove 501 in a one-to-one manner. The limit protection ring 51 is detachably connected to the limit connecting ring 50, and the limit protection ring 51 is sleeved on the outer periphery of the clamping jaw 3.

[0038] Because the limiting connecting ring 50 and the clamping jaws 3 are slidably connected to the limiting connecting ring 50 via the through-slots 501 of the support legs 500, the rotation of the limiting connecting ring 50 can drive the clamping jaws 3 to rotate synchronously, thereby transmitting the rotational force to the clamped bolt, thereby achieving the bolt tightening operation. During this process, the through-slots 501 of the limiting connecting ring 50 serve as a guide structure, eliminating additional support and also acting as a limiter, ensuring that the clamping jaws 3 do not move excessively, achieving multi-degree-of-freedom movement within a confined space. The polygonal prismatic structure of the limiting connecting ring 50 utilizes its regular geometric shape and stable mechanical transmission properties to ensure that the clamping jaws 3 are evenly loaded during rotation, avoiding deflection or slippage, and significantly improving the accuracy and reliability of bolt tightening. The limiting protection ring 51 is placed on the periphery of the clamping jaws 3. Its main function is to establish a mechanical limit. By being installed on the outside of multiple clamping jaws 3, it effectively prevents excessive axial displacement of the clamping jaws 3.

[0039] Optional, reference Figure 2 and Figure 6 The telescopic mechanism 2 also includes a first motor seat 2020, which is provided with a first cavity matching the first motor 202. The first motor 202 is fixed in the first cavity. A conductive ring 2021 is fixed on the outside of the first motor seat 2020. The first electrode piece 2022 led out from the inside of the first motor 202 is in sliding contact with the first side of the conductive ring 2021 to transmit the working current of the first motor 202. The second electrode piece 2023 connected to the control line is in sliding contact with the second side of the conductive ring 2021 to transmit the forward and reverse control signal and power supply.

[0040] Specifically, both the first motor 202 and the second motor 4 are brushless motors.

[0041] The first motor 202 drives the linear reciprocating assembly 20 to perform linear reciprocating motion. The linear movement of the linear reciprocating assembly 20 is converted by the connecting rod assembly 21 into the radial expansion and contraction of the clamping jaw 3 to adapt to bolts of different specifications. When the clamping jaw 3 completes radial contraction under the drive of the linear reciprocating assembly 20 and successfully clamps the bolt head, the second motor 4 starts and drives the first motor base 2020 with stable torque output, thereby driving the first motor base 2020 and the central axis of the limiting connecting ring 50 to rotate. Since the limiting connecting ring 50 and the clamping jaw 3 are slidingly connected to the limiting connecting ring 50 through the support foot 500 through the slot 501, the rotation of the limiting connecting ring 50 can drive the clamping jaw 3 to rotate synchronously, thereby transmitting the rotational power to the clamped bolt, thereby realizing the tightening operation of the bolt. The dual motors are independently driven to achieve precise and intelligent motion control. The second motor 4 ensures stable tightening force, and the first motor 202 ensures rapid response to diameter changes, greatly improving work efficiency. The wide applicability, with flexible and variable bolt sizes, can meet the operational needs of bolts in multiple fields and specifications, reducing tool procurement costs and equipment idle rates. In the dual-motor drive system, the conductive ring 2021 conducts electricity through sliding contact, achieving decoupling of electrical connection and mechanical movement, allowing the first motor 202 to rotate 360° without restrictions, effectively avoiding failures of traditional cables caused by entanglement and breakage, and the failure frequency is much lower than that of traditional cable connections. The conductive ring 2021 is compactly installed, saving mechanical space and simplifying the assembly process. The wear-resistant surface treatment and sealing design give it the characteristics of long life, maintenance-free and strong environmental adaptability.

[0042] Optional, reference Figure 2 and Figure 8 The shell 1 includes a first shell 10 and a second shell 11 that are detachably connected. A second cavity 110 matching the second motor 4 is opened in the second shell 11. The second motor 4 is fixed in the second cavity 110, and the clamp 3 extends out of the first shell 10.

[0043] Specifically, the shell 1 is made of lightweight high-strength aluminum alloy and is anodized to have good corrosion resistance and wear resistance. The shell 1 is 230 mm long and has a maximum outer diameter of 50 mm. The first shell 10 and the second shell 11 are both left-right symmetrical structures, and the left and right parts are connected by bolts.

[0044] The first housing 10 serves as a front protective shield, employing a streamlined frustum to enclose the limiting connecting ring 50 and the linear reciprocating assembly 20. Its open design ensures adequate working space for the tool head while effectively preventing external dust from invading the core transmission mechanism. The second housing 11 serves as the power compartment. Its T-shaped structure provides a stable gripping surface through a vertical extension, while the transverse main body houses a second cavity 110, ensuring both lightweight construction and structural rigidity.

[0045] Optional, reference Figure 3A plurality of control buttons 6 are connected to the vertical portion of the second shell 11 , and the plurality of control buttons 6 control the forward and reverse rotation and start and stop of the second motor 4 , as well as the reciprocating movement and start and stop of the linear reciprocating motion component 20 .

[0046] Specifically, the control button 6 includes: a first button 60, a second button 61, a third button 62 and a fourth button 63. The first button 60 controls the forward and reverse rotation of the first motor 202, the second button 61 controls the forward and reverse rotation of the second motor 4, the third button 62 controls the start and stop of the first motor 202, and the fourth button 63 controls the start and stop of the second motor 4.

[0047] Optional, reference Figure 1 and Figure 7 A plurality of clamping jaws 3 extend out of one end of the housing 1 and are fixed with a clamping head 30 , which faces inward and has tooth-like anti-slip patterns.

[0048] The anti-slip pattern significantly increases the friction coefficient between the clamp head 30 and the bolt head, preventing slippage during tightening. This is particularly effective for bolts with smooth or oily surfaces. The clamp head 30 is designed to automatically compensate for dimensional tolerances of bolts of varying specifications, ensuring a perfect fit between the clamping surface and the sidewalls of the bolt head. The enveloping clamping mechanism formed by multiple clamp heads 30 evenly distributes tightening torque, preventing damage to the bolt head caused by single-point stress concentration. The special pattern of the clamp head 30 serves as a visual indicator, allowing the operator to quickly confirm the proper alignment of the tool and the bolt.

[0049] Optionally, the linear reciprocating motion assembly 20 can be adapted to connect to connecting rod assemblies 21 of different specifications.

[0050] Remove the first shell 10 from the second shell 11, then disassemble the limiting connecting ring 50 and the first motor base 2020, and replace the limiting connecting ring 50 and the connecting rod assembly 21 in the front half. Replacing the limiting connecting ring 50 and the connecting rod assembly 21 with different specifications can increase the adaptability range of the bolts.

[0051] This embodiment provides an electric wrench with adjustable diameter, which adopts a dual-motor collaborative drive system to achieve precise torque output and adaptive diameter change function, and both motors are brushless motors. The first motor 202 directly drives the external thread stud 201 to rotate through the output shaft that passes through the limit connection ring 50, and drives the clamping claw 3 to complete radial opening and closing through the evenly distributed connecting rod assembly 21. The standard working range covers M20-M24 bolts. In this embodiment, the M6 ​​standard concave structure 2000 is integrated at the end of the internal thread stud 200 to realize the direct embedding and tightening mode of the standard bolt, and can be expanded to M24-M32 specifications by replacing modular components. The front end of the second shell 11 is connected to the waterproof and dustproof first shell 10, and the rear end is integrated with a centrifugal cooling fan to ensure continuous and stable operation of the equipment. Four waterproof buttons are set for human-computer interaction to control the forward and reverse rotation and start and stop of the two motors respectively.

[0052] When tightening a bolt, the operator presses the first button 60 to switch the first motor 202 to forward rotation mode. The second button 61 is then pressed to start the first motor 202. The first motor 202 drives the internal and external studs 200 and 201 to move relative to each other, allowing the jaws 3 to quickly extend and accurately grip the bolt head. Once the jaws 3 are in position, the second button 61 is pressed again to stop the first motor 202. The operator presses the third button 62 to switch the second motor 4 to forward rotation mode. The fourth button 63 is then pressed to start the second motor 4. The second motor 4, via the limiting connecting ring 50, drives the jaws 3 to rotate smoothly, tightening the bolt at a constant torque. Once the bolt is tightened, the operator presses the fourth button 63 to stop tightening. The first button 60 is then pressed again to switch the first motor 202 to reverse rotation mode. The second button 61 is then pressed to start the operation, releasing the jaws 3 and disengaging them from the bolt. To remove the bolt, the operator simply presses the third button 62 to switch the second motor 4 to reverse rotation mode.

[0053] The above utility models are only several specific embodiments of the present utility model. However, the embodiments of the present utility model are not limited thereto. Any changes that can be thought of by those skilled in the art should fall within the scope of protection of the present utility model.

Claims

1. An electric wrench with adjustable diameter, characterized in that: include: A shell (1), a telescopic mechanism (2), and a plurality of clamping claws (3), wherein the shell (1) is pistol-shaped, the telescopic mechanism (2) is connected to the shell (1), and the plurality of clamping claws (3) are surrounded by the telescopic mechanism (2) and have one end extending out of the shell (1); The telescopic mechanism (2) comprises: a linear reciprocating moving component (20) and a plurality of connecting rod components (21), wherein the linear reciprocating moving component (20) reciprocates along the horizontal axis of the housing (1), and the connecting rod component (21) converts the linear motion of the linear reciprocating moving component (20) into radial contraction and expansion of the clamping claw (3); The connecting rod assembly (21) includes a first connecting rod (210), a second connecting rod (211), a third connecting rod (212) and a sleeve (213); the first connecting rod (210) is fixed to the inner wall of the clamp (3); the sleeve (213) is connected to the moving end of the linear reciprocating moving assembly (20); the second connecting rod (211) is distributed circumferentially on the sleeve (213); the second connecting rod (211) is connected to the first connecting rod (210) in a one-to-one correspondence through the third connecting rod (212); the first end of the third connecting rod (212) is rotatably connected to the first connecting rod (210), and the second end is rotatably connected to the second connecting rod (211); A second motor (4) is fixed in the housing (1), and an output end of the second motor (4) is connected to the telescopic mechanism (2). The second motor (4) drives the telescopic mechanism (2) to rotate, thereby driving the multiple clamping claws (3) to rotate synchronously.

2. The electric wrench with adjustable diameter according to claim 1, characterized in that: The linear reciprocating motion assembly (20) comprises: an internal threaded stud (200), an external threaded stud (201) and a first motor (202); the internal threaded stud (200) and the external threaded stud (201) are engaged with each other via a threaded pair; the internal threaded stud (200) is nested in a sleeve (213); and the external threaded stud (201) is connected to an output end of the first motor (202).

3. The electric wrench with adjustable diameter according to claim 2, characterized in that: An inner concave structure (2000) is provided at one end of the inner thread stud (200) extending out of the housing (1), and the inner concave structure (2000) is a regular hexagon.

4. The electric wrench with adjustable diameter according to claim 1, characterized in that: The invention also includes a limiting component (5), wherein the limiting component (5) includes: a limiting connection ring (50) and a limiting protection ring (51), wherein the limiting connection ring (50) is a regular hexagonal prism, and a plurality of supporting legs (500) are distributed on the side of the limiting connection ring (50), and a through groove (501) is provided on the supporting legs (500), and a plurality of the clamping jaws (3) are slidably connected in the through groove (501) in a one-to-one manner, and the limiting protection ring (51) is detachably connected to the limiting connection ring (50), and the limiting protection ring (51) is sleeved on the outer periphery of the clamping jaws (3).

5. The electric wrench with adjustable diameter according to claim 1, characterized in that: The telescopic mechanism (2) further comprises a first motor seat (2020), the first motor seat (2020) being provided with a first cavity matching the first motor (202), the first motor (202) being fixed in the first cavity, a conductive ring (2021) being fixed on the outside of the first motor seat (2020), a first electrode sheet (2022) led out from the inside of the first motor (202) being in sliding contact with a first side of the conductive ring (221) to transmit the working current of the first motor (202), and a second electrode sheet (2023) connected to a control line being in sliding contact with a second side of the conductive ring (2021) to transmit a forward and reverse rotation control signal and a power supply.

6. The electric wrench with adjustable diameter according to claim 1, characterized in that: The housing (1) comprises a first housing (10) and a second housing (11) which are detachably connected. A second cavity (110) matching the second motor (4) is provided in the second housing (11). The second motor (4) is fixed in the second cavity (110). The clamping claw (3) extends out of the first housing (10).

7. The electric wrench with adjustable diameter according to claim 6, characterized in that: A plurality of control buttons (6) are connected to the vertical portion of the second shell (11), and the plurality of control buttons (6) control the forward and reverse rotation and start and stop of the second motor (4), as well as the reciprocating movement and start and stop of the linear reciprocating component (20).

8. The electric wrench with adjustable diameter according to claim 1, characterized in that: A clamping head (30) is fixed to one end of the plurality of clamping jaws (3) extending out of the housing (1), the clamping head (30) faces inward, and a tooth-shaped anti-slip pattern is provided on the clamping head (30).

9. The electric wrench with adjustable diameter according to claim 1, characterized in that: The linear reciprocating motion assembly (20) can be adapted to connect connecting rod assemblies (21) of different specifications.

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