Automatic centering clamping mechanism and centering method

Abstract

The present invention relates to the technical field of engineering machinery clamping, and in particular to an automatic centering clamping mechanism and a centering method, comprising: a clamping power unit, used to provide rotational power for the clamping action; a screw rod, which is installed to rotate synchronously with the power end of the clamping power unit; a clamping assembly, which is installed on the screw rod and includes two nut assemblies, which respectively drive the clamping jaws to move horizontally toward or away from each other along the screw rod. When moving toward each other, when the clamping jaws of one of the nut assemblies contact with a workpiece, it automatically stops moving toward the workpiece, and is used to solve the technical problems that the clamping mechanism in the prior art generally has, such as the inability to automatically center the clamping, the low clamping efficiency caused by uneven clamping force, and the easy falling off after clamping.

Description

Technical Field

[0001] The invention relates to the technical field of engineering machinery clamping, in particular to an automatic centering clamping mechanism and a centering method. Background Art

[0002] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

[0003] There are some clamping or grasping scenarios in the engineering field. The clamped or grasped objects cannot move during the clamping action. At the same time, the tool's jaws are required to be accurately located in the geometrically symmetrical position of the clamped or grasped objects, thereby ensuring the symmetry of the clamping force of the jaws on the object and providing quality assurance for subsequent processing or handling operations.

[0004] In the current related technologies, an effective way to solve the above problems is to use visual recognition technology to obtain the precise shape and orientation coordinates of the clamped or grasped object by taking a photo, and then drive the mechanical arm to drive the clamp or gripper to move to the object position for subsequent actions. Such a solution is highly dependent on image recognition technology, and the recognition accuracy and recognition algorithm will affect the positioning accuracy of the gripper, especially for objects with a small photographing area, which requires higher recognition accuracy and corresponding hardware support. There are certain limitations in terms of actual positioning effect and equipment investment.

[0005] Another solution is to first use rough positioning to drive the robot arm with a camera to the vicinity of the position that needs to be clamped or grasped, and then use the camera installed on it to take a second photo to obtain higher-precision position coordinates at a close distance, so as to drive the robot arm to drive the clamping claw to achieve precise positioning and complete the precise clamping action. Although this method can accurately achieve positioning and complete the clamping or grasping action, the equipment is relatively complex, the hardware investment is large, and the positioning accuracy is still limited by hardware and software. At the same time, the high requirements of image recognition technology for the on-site environment also limit the promotion and application of this method.

[0006] Chinese patent application CN202622621U discloses a self-locking centering clamping mechanism, including a workbench, two fixed support seats, a linear guide rail, a bidirectional lead screw pair, two movable splints, two V-shaped blocks, a drive shaft and an overrunning clutch. The two fixed support seats are fixed on the workbench, the linear guide rail includes a guide rod and two guide blocks sleeved on the guide rod, the bidirectional lead screw pair includes a lead screw and two sliding nuts, the guide rod is parallel to the lead screw axis and both ends are respectively fixed on the fixed support seats, the two movable splints are respectively fixed on the guide blocks and sliding nuts on the left and right sides, the two V-shaped blocks are respectively fixed on the movable splints, one end of the lead screw extends out of the fixed support seat and is connected to one end of the drive shaft through an overrunning clutch, the structure is simple, It is easy to operate, can realize automatic locking and centering, save process costs, and has high reliability. However, related technologies including the technical solutions of the above-mentioned open patent applications still have the following technical problems: ① For working conditions where the workpiece cannot move, the synchronous clamping on both sides requires that the workpiece is exactly located at the geometric center of the clamping components on both sides. Otherwise, the centered clamping cannot be guaranteed during clamping, and it is easy for the clamping component on one side to contact the workpiece while there is still a gap between the clamping component on the other side and the workpiece. At this time, it is easy to cause uneven clamping force on both sides of the workpiece, resulting in the workpiece being unable to be clamped or easily falling off after being clamped; ② The clamping of workpieces in a narrow area has higher requirements on the accuracy of both equipment hardware and software, and the difficulty and cost of implementation are relatively high. Summary of the invention

[0007] The purpose of the present invention is to provide an automatic centering clamping mechanism to solve the technical problems commonly existing in the prior art clamping mechanisms, such as the inability to automatically center the clamping, the low clamping efficiency caused by uneven clamping force, and the easy falling off after clamping.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] An automatic centering clamping mechanism, comprising:

[0010] A clamping power unit, used to provide rotational power for the clamping action;

[0011] The screw is installed to rotate synchronously with the power end of the clamping power unit;

[0012] The clamping assembly is installed on the screw and includes two nut assemblies. The two nut assemblies respectively drive a clamping jaw to move horizontally toward or away from the screw. When moving toward each other, when the clamping jaw of one of the nut assemblies contacts the workpiece, it automatically stops moving toward the workpiece.

[0013] Furthermore, the nut assembly includes a first nut body and a second nut body, the first nut body is threadedly connected to the screw rod, and the second nut body is relatively fixedly connected or relatively rotatably connected to the first nut body through a clutch power assembly.

[0014] Furthermore, the clutch power assembly is installed on the second nut body and is located between the first nut body and the second nut body. The clutch power assembly includes a clutch power unit and a working end installed at its power end. The clutch power unit drives the working end to extend and retract so that the second nut body and the first nut body can be separated and combined.

[0015] Furthermore, a pressure sensor is installed between the first nut body and the second nut body, and one side of the pressure sensor is rotatably installed relative to the first nut body, and the other side of the pressure sensor is fixedly installed relative to the second nut body.

[0016] Furthermore, the clutch power unit adopts an electromagnetic clutch, and a friction ring that cooperates with the working end is installed on the first nut body. When the working end is driven by the electromagnetic clutch, it contacts and tightens with the friction ring to achieve relative fixation of the first nut body and the second nut body.

[0017] Furthermore, the clutch power unit adopts an electromagnetic clutch, and a magnetic ring that cooperates with the working end is installed on the first nut body. When the working end is driven by the electromagnetic clutch, it contacts and tightens with the magnetic ring to achieve relative fixation of the first nut body and the second nut body.

[0018] Furthermore, the screw rod is provided with a first thread and a second thread, the first thread and the second thread have opposite rotation directions, and the first nut bodies of the two nut assemblies are threadably connected to the screw rod through the first thread and the second thread respectively.

[0019] Furthermore, both nut assemblies are provided with through holes for the guide rods to pass through in sequence, and the guide rods are slidably mounted on the second nut body.

[0020] A method for centering a workpiece by automatically centering the workpiece, the method comprising the following steps:

[0021] S1, the clamping mechanism returns to zero, at which point the distance between the two clamping jaws is at its maximum, and the first nut body and the second nut body are in a fitted state; S2, the clamping power unit is activated, driving the screw to rotate, and the screw drives the two nut assemblies to move horizontally toward each other, and the two clamping jaws move horizontally toward each other synchronously to approach the workpiece to be clamped;

[0022] S3. When the clamping jaws of any one of the nut assemblies contact the workpiece to be clamped, the corresponding pressure sensor detects that the reaction force of the workpiece to be clamped reaches a set value, and a signal is transmitted to the clutch power assembly to make it act, and the first nut body and the second nut body are in a separated state. At this time, the first nut body and the screw rotate synchronously, the second nut body stops moving, and the nut assembly stops moving forward;

[0023] S4, the other nut assembly continues to move towards the direction of the workpiece to be clamped until the nut assembly contacts and tightens against the workpiece to be clamped, the clamping power unit stops running, and the clamping action is completed;

[0024] S5. After the clamping task is completed, the clamping mechanism returns to zero: the controller sends a signal to the clutch power assembly, the clutch power assembly operates to combine the first nut body and the second nut body, and the clamping power unit runs in the reverse direction, driving the nut assembly to move back to the initial position. When one of the nut assemblies reaches the initial position first, its pressure sensor transmits a signal to cause the clutch power assembly to operate, and the nut assembly is in a separated state. The other nut assembly continues to run to the initial position, the clamping power unit stops running, and the clamping mechanism completes the zeroing action.

[0025] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0026] (1) The present invention sets a clutch power component to realize that the two nut components move toward each other for clamping. When any one of the nut components contacts the workpiece to be clamped first, it can stop moving, and the other nut component continues to run until both of them clamp the workpiece to be clamped. It can realize that the same screw drives the two nut components to clamp and control the operation of the two nut components separately. There is no need to accurately position the two clamping jaws to the center position of the workpiece to be clamped in advance by precise control such as visual recognition, which greatly reduces the difficulty of accurately positioning the relative position between the clamping mechanism and the workpiece to be clamped, avoids the problem of uneven clamping force on both sides and easy falling off after clamping when the workpiece cannot move in the traditional clamping mechanism, realizes the function of automatic centering clamping and fixing, and improves the clamping efficiency and clamping accuracy.

[0027] (2) The present invention uses a single screw rod to realize the movement of two nut assemblies toward or away from each other. Compared with the traditional related technology that uses two screw rods to realize the individual control of the nuts, the structure of the present invention is simpler and more compact, and the structural rigidity is better. After long-term use, the position accuracy between the component structures is well maintained. At the same time, the control is simple and easy to achieve synchronization. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a front view of the present invention;

[0029] Figure 2 A bottom view of the present invention;

[0030] Figure 3 for Figure 2 Sectional view at AA;

[0031] Figure 4 Schematic diagram of the internal structure of the nut assembly.

[0032] In the figure, 100, a clamping power unit;

[0033] 200, bracket;

[0034] 300, guide rod;

[0035] 400, screw; 401, first thread; 402, second thread;

[0036] 500, Gripper;

[0037] 700, nut assembly; 701, second nut body; 702, first nut body; 703, first bearing; 704, clutch power assembly; 705, working end; 706, pressure sensor; 707, second bearing; 708, friction ring; 709, end cover. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] The drawings are for illustrative purposes only and should not be construed as limiting the present patent;

[0040] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments and are not intended to limit the embodiments of the present application. The singular forms "a", "the" and "the" used in the embodiments of the present application and the appended claims are not intended to limit the embodiments of the present application.

[0041] "The" is also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and encompasses any or all possible combinations of one or more of the associated listed items.

[0042] When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Instead, they are only examples of devices and methods consistent with some aspects of the present application as detailed in the attached claims.

[0043] In the description of this application, it should be understood that the terms "first", "second", "third", etc. are only used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence, nor can they be understood as indicating or implying relative importance. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0044] In addition, in the description of the present application, unless otherwise specified, "plurality" means two or more. "and / or",

[0045] Describing the association relationship of associated objects, it means that there can be three kinds of relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0046] In order to solve the limitations of the prior art, this embodiment provides a technical solution, and the technical solution of the present invention is further described below in conjunction with the drawings and embodiments.

[0047] The present invention aims to improve the problem that the centering clamping mechanism in the related art cannot realize automatic centering when clamping a product that cannot be moved, which leads to uneven clamping force on the clamped workpiece and easy falling off after clamping. The specific technical solution is as follows:

[0048] See attached Figure 1-3, an automatic centering clamping mechanism, comprising: a clamping power unit 100, used to provide rotational power for the clamping action, wherein the clamping power unit 100 uses a rotary motor, and the rotary motor provides rotational power to drive the screw 400 to rotate; the screw 400 is installed to rotate synchronously with the power end of the clamping power unit 100, wherein the screw 400 and the power output shaft of the rotary motor are synchronously rotated through a coupling, and a first thread 401 and a second thread 402 are arranged on the screw 400, and the first thread 401 and the second thread 402 have opposite rotation directions, and the two nut assemblies 700 are moved toward or away from each other by using a single screw 400, which is different from the conventional related technology that uses two screws 40 0 For realizing the respective control of the nut, the structure of the present invention is simpler and more compact, and the structural rigidity is better. After long-term use, the position accuracy between the component structures is well maintained, and the control is simple and easy to achieve synchronization; the clamping assembly is installed on the screw rod 400 and includes two nut assemblies 700 on which the clamping jaws 500 are respectively installed. The two nut assemblies 700 are both provided with through holes for the guide rod 300 to pass through in sequence. The guide rod 300 and the second nut bodies 701 of the two nut assemblies 700 are both slidably installed. Here, the guide rod 300 and the clamping power unit 100 are both fixedly installed relative to the bracket 200, and the screw rod 400 is rotatably installed relative to the bracket 200, and the implementation method is to install it through a bearing. The two nut assemblies 700 drive the clamping jaws 500 to move horizontally toward or away from each other along the screw rod 400. When moving toward each other, the clamping jaws 500 of one of the nut assemblies 700 automatically stop moving toward the workpiece after contacting the workpiece. By setting the clutch power assembly 704, the two nut assemblies 700 can move toward each other for clamping. When one of the nut assemblies 700 contacts the workpiece to be clamped first, it can stop moving, and the other nut assembly 700 continues to run until both clamp the workpiece to be clamped. The same screw rod 400 can drive the two nut assemblies 700 to clamp while controlling the operation of the two nut assemblies 700 separately. There is no need to accurately position the two clamping jaws 500 to the center position of the workpiece to be clamped in advance through precise control such as visual recognition. This greatly reduces the difficulty of accurately positioning the relative position between the clamping mechanism and the workpiece to be clamped, and avoids the phenomenon that the workpiece cannot be moved in the traditional clamping mechanism, resulting in uneven clamping force on both sides and easy falling off after clamping. The function of automatic centering clamping and fixing is realized, and the clamping efficiency and clamping accuracy are improved.

[0049] Specifically, the nut assembly 700 includes a first nut body 702 and a second nut body 701. The first nut bodies 702 of the two nut assemblies 700 are threadedly connected to the screw rod 400 through the first thread 401 and the second thread 402, respectively. Figure 2-4The first nut body 702 is threadedly connected to the screw rod 400, and the second nut body 701 is relatively fixedly connected or relatively rotatably connected to the first nut body 702 through the clutch power assembly 704. Here, the relatively fixed connection can be understood as the synchronous translation movement of the first nut body 702 and the second nut body 701, and the relative rotation connection can be understood as the relative rotation of the first nut body 702 and the second nut body 701. Specifically, the clutch power assembly 704 is installed on the second nut body 701 and is located between the first nut body 702 and the second nut body 701. The clutch power assembly 704 includes a clutch power unit and a working end 705 installed at its power end. The clutch power unit drives the working end 705 to extend and retract so that the second nut body 701 and the first nut body 702 can be separated and combined. A pressure sensor 706 is installed between the first nut body 702 and the second nut body 701. One side of the pressure sensor 706 is relatively rotatably installed with the first nut body 702, and the other side is relatively fixedly installed with the second nut body 701. The specific implementation method is: a concave space is set along the center of one end of the second nut body 701, and the first nut body 702 is located in the concave space, and then the second bearing 707 is installed between the first nut body 702 and the end cover 709, and the end cover 709 is fixedly installed on the end face of the second nut body 701. Here, the second bearing 707 adopts a thrust bearing, one side of the pressure sensor 706 is fixedly installed with the shaft piece of the first bearing 703, and the other side of the pressure sensor 706 is fixedly connected to the second nut body 701, and the seat piece on one side of the first bearing 703 is tightly installed on the first nut body 702. Here, the first bearing 703 adopts a thrust bearing. In the present invention, the clamping power unit 100, the pressure sensor 706 and the clutch power unit are all controlled by the controller. The principle is explained here as follows: the force transmitted by the screw 400 through the thread will be transmitted in turn by the first The nut body 702 transmits the force to the first bearing 703, and the first bearing 703 transmits the force to the pressure sensor 706. The pressure sensor 706 is supported by the second nut body 701. The force transmitted by the screw 400 through the clamping power unit 100 acts on the second nut body 701, thereby achieving force balance. When the clamping jaw 500 of the second nut body 701 is blocked and cannot move horizontally due to contact with the workpiece to be detected, the resistance transmitted to the second nut body 701 by the screw 400 increases, and the pressure sensor 706 receives a signal of increased force, that is, it is judged that the clamping jaw 500 has contacted the workpiece to be clamped. The pressure sensor 706 transmits the force signal to the controller, and the controller controls the action of the clutch power unit to realize the separation of the first nut body 702 and the second nut body 701. The first nut body 702 rotates freely, while the second nut body 701 is stationary.

[0050] See attached Figure 4The clutch power unit adopts an electromagnetic clutch, and a friction ring 708 that cooperates with the working end 705 is installed on the first nut body 702. When the working end 705 is driven by the electromagnetic clutch, it is in contact with the friction ring 708 to achieve relative fixation between the first nut body 702 and the second nut body 701. Here, the working end 705 and the friction ring 708 are in contact with each other to achieve relative fixation through friction.

[0051] In addition, the clutch power unit can also be implemented in other ways, for example: the clutch power unit adopts an electromagnetic clutch, and a magnetic ring that cooperates with the working end 705 is installed on the first nut body 702. When the working end 705 is driven by the electromagnetic clutch, it is contacted and tightened with the magnetic ring to achieve relative fixation of the first nut body 702 and the second nut body 701. Here, the contact and tightening of the working end 705 and the magnetic ring is achieved by magnetic suction force.

[0052] A method for centering a workpiece by automatically centering the workpiece, the method comprising the following steps: S1, the clamping mechanism is reset to zero, at which time the distance between the two clamping jaws 500 is at its maximum, the clutch power assembly 704 is in a powered state, and the first nut body 702 and the second nut body 701 are in a combined state; S2, the clamping power unit 100 is actuated to drive the screw rod 400 to rotate, and the screw rod 400 drives the two nut assemblies 700 to move horizontally toward each other, at which time the first nut body 702 rotates driven by the screw rod 400 and is blocked by the second nut body 701, thereby driving the second nut body 701 to move translationally along the guide rod 300 , thereby driving the clamping jaws on the second nut body 701 to translate, and the two clamping jaws 500 move synchronously toward each other horizontally at the same speed to approach the workpiece to be clamped; S3, when the clamping jaws 500 of any one of the nut assemblies 700 contacts the workpiece to be clamped, the pressure sensor 706 detects that the reaction force of the workpiece to be clamped reaches the set value, and the signal is transmitted to the clutch power assembly 704 to make it act, and the first nut body 702 and the second nut body 701 are in a separated state. At this time, the first nut body 702 and the screw 400 rotate synchronously, and the second nut body 701 stops moving, thereby realizing the stopping action of the clamping jaws, from the force angle Analysis shows that when the clamping jaw 500 contacts the workpiece to be clamped, due to the reaction force of the workpiece to be clamped, the clamping jaw 500 will apply an axial force in the opposite direction to the second nut body 701. According to the screw-nut transmission principle, the nut has a reverse self-locking function along the axis. Therefore, once the clamping jaw 500 contacts the workpiece to be clamped, the force applied to the workpiece to be clamped will be maintained. S4, the other nut assembly 700 continues to move in the direction close to the workpiece to be clamped until the nut assembly 700 contacts and tightens with the workpiece to be clamped, the clamping power unit 100 stops running, and the clamping action is completed. S5, clamping After the task is completed, the clamping mechanism returns to zero: the controller sends a signal to the clutch power assembly 704, the clutch power assembly 704 operates to combine the first nut body 702 and the second nut body 701, and the clamping power unit 100 runs in the reverse direction, driving the nut assembly 700 to move back to the initial position. When one of the nut assemblies 700 reaches the initial position first, its pressure sensor 706 transmits a signal to activate the clutch power assembly 704, and the nut assembly 700 is in a separated state. The other nut assembly 700 continues to run to the initial position, the clamping power unit 100 stops running, and the clamping mechanism completes the zeroing action.

[0053] The clamping mechanism disclosed in the present invention is not only suitable for conventional workpiece clamping, but also for workpieces with smaller sizes and narrow clamping spaces. At the same time, it avoids the high cost generated by the traditional use of visual auxiliary equipment and the high requirements for the accuracy of each component of the equipment, and the clamping efficiency and clamping accuracy are significantly improved.

[0054] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An automatic centering clamping mechanism, characterized in that: include: A clamping power unit (100), used to provide rotational power for the clamping action; The screw rod (400) is installed to rotate synchronously with the power end of the clamping power part (100); A clamping assembly is mounted on the screw rod (400) and comprises two nut assemblies (700). The two nut assemblies (700) respectively drive the clamping jaws (500) to move horizontally toward or away from each other along the screw rod (400). When moving toward each other, when the clamping jaws (500) of one of the nut assemblies (700) contacts a workpiece, the clamping jaws (500) automatically stop moving toward the workpiece. The nut assembly (700) comprises a first nut body (702) and a second nut body (701); the first nut body (702) is threadedly connected to the screw rod (400); and the second nut body (701) is fixedly connected or rotatably connected to the first nut body (702) via a clutch power assembly (704); The clutch power assembly (704) is mounted on the second nut body (701) and is located between the first nut body (702) and the second nut body (701). The clutch power assembly (704) comprises a clutch power unit and a working end (705) mounted on the power end thereof. The clutch power unit drives the working end (705) to extend and retract so that the second nut body (701) and the first nut body (702) can be separated and assembled. A pressure sensor (706) is installed between the first nut body (702) and the second nut body (701); one side of the pressure sensor (706) is rotatably installed relative to the first nut body (702), and the other side of the pressure sensor (706) is fixedly installed relative to the second nut body (701).

2. The automatic centering clamping mechanism according to claim 1, characterized in that: The clutch power unit adopts an electromagnetic clutch, and a friction ring (708) matched with the working end (705) is installed on the first nut body (702). When the working end (705) moves under the drive of the electromagnetic clutch, it contacts and presses against the friction ring (708) to achieve relative fixation of the first nut body (702) and the second nut body (701).

3. The automatic centering clamping mechanism according to claim 2, characterized in that: The clutch power unit adopts an electromagnetic clutch, and a magnetic ring that cooperates with the working end (705) is installed on the first nut body (702). When the working end (705) is driven by the electromagnetic clutch, it contacts and presses against the magnetic ring to achieve relative fixation of the first nut body (702) and the second nut body (701).

4. An automatic centering clamping mechanism according to any one of claims 2-3, characterized in that: The screw rod (400) is provided with a first thread (401) and a second thread (402), the first thread (401) and the second thread (402) having opposite rotation directions, and the first nut bodies (702) of the two nut assemblies (700) are threadedly connected to the screw rod (400) via the first thread (401) and the second thread (402), respectively.

5. The automatic centering clamping mechanism according to claim 4, characterized in that: The two nut assemblies (700) are both provided with through holes for the guide rods (300) to pass through in sequence, and the guide rods (300) are slidably mounted on the second nut body (701).

6. A centering method, based on an automatic centering clamping mechanism according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: S1, the clamping mechanism returns to zero, at which point the distance between the two clamping jaws (500) is at its maximum, and the first nut body (702) and the second nut body (701) are in a fitted state; S2, the clamping power unit (100) is activated to drive the screw (400) to rotate, the screw (400) drives the two nut assemblies (700) to move horizontally toward each other, and the two clamping jaws (500) move horizontally toward each other synchronously to approach the workpiece to be clamped; S3. When the clamping jaw (500) of any one of the nut assemblies (700) contacts the workpiece to be clamped, the corresponding pressure sensor (706) detects that the reaction force of the workpiece to be clamped reaches a set value, and a signal is transmitted to the clutch power assembly (704) to make it actuate, and the first nut body (702) and the second nut body (701) are in a separated state. At this time, the first nut body (702) and the screw rod (400) rotate synchronously, the second nut body (701) stops moving, and the nut assembly (700) stops moving forward; S4, the other nut assembly (700) continues to move in a direction close to the workpiece to be clamped until the nut assembly (700) is in contact with and tightly pressed against the workpiece to be clamped, and the clamping power unit (100) stops running, and the clamping action is completed.

7. A centering method according to claim 6, characterized in that: Also includes: S5. After the clamping task is completed, the clamping mechanism returns to zero: the controller sends a signal to the clutch power assembly (704), the clutch power assembly (704) operates to make the first nut body (702) and the second nut body (701) merge, the clamping power unit (100) runs in the reverse direction, driving the nut assembly (700) to move in the reverse direction to the initial position. When one of the nut assemblies (700) reaches the initial position first, its pressure sensor (706) transmits a signal to make the clutch power assembly (704) operate, the nut assembly (700) is in a separated state, and the other nut assembly (700) continues to run to the initial position, the clamping power unit (100) stops running, and the clamping mechanism completes the zeroing action.

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