Variable pitch bearing bolt tightening apparatus, system, and method

Abstract

The embodiment of the application relates to the field of wind power generation, and provides a variable-pitch bearing bolt tightening device, system and method, wherein the device comprises a gantry frame, the gantry frame comprising a frame body, a mounting plate base and a bearing connecting plate, the mounting plate base being fixed on the frame body, the bearing connecting plate being detachably connected with the mounting plate base, and the bearing connecting plate being used for fixedly connecting with an inner ring of a variable-pitch bearing; a three-axis movement mechanism, the three-axis movement mechanism being arranged in the frame body, the three-axis movement mechanism comprising a movement end movable in a three-dimensional space; a tightening execution mechanism, the tightening execution mechanism being connected with the movement end, and the tightening execution mechanism comprising an electric tightening assembly; and a rotary electrical connection mechanism, the rotary electrical connection mechanism being arranged at the bottom of the frame body, and the rotary electrical connection mechanism being used for transmitting electrical signals when the gantry frame rotates with the variable-pitch bearing. At least the problem that a cable is prone to being wound and broken during rotary operation can be solved.

Description

Technical Field

[0001] This application relates to the field of wind power generation, and in particular to a pitch bearing bolt tightening device, system and method. Background Technology

[0002] Hub assembly is a critical process in wind turbine manufacturing, and the quality of the bolt connection between the pitch bearing and the hub directly affects the operational safety and service life of the wind turbine. The pitch bearing connects the hub and blades, enabling pitch angle adjustment. It is typically secured to the hub with dozens to hundreds of high-strength bolts, requiring a strict tightening process involving two steps: pre-tightening and final tightening. Each step is marked for quality traceability.

[0003] However, for tightening equipment that operates by rotating with the pitch bearing, the electrical cables and air hoses on the equipment need to be connected to an external electrical control cabinet to obtain power and control signals. When the equipment rotates with the pitch bearing, these cables and air hoses will rotate with the equipment, posing a risk of entanglement or breakage, which may cause the equipment to malfunction and seriously affect the continuous operation capability and service life of the equipment. Summary of the Invention

[0004] This application provides a pitch bearing bolt tightening device, system, and method, which at least helps to solve the problem of cables easily getting tangled and broken during rotation operations.

[0005] According to some embodiments of this application, one aspect of this application provides a pitch bearing bolt tightening device, comprising: a gantry frame, the gantry frame including a frame body, a mounting plate base provided at the bottom of the frame body, a bearing connecting plate detachably connected to the mounting plate base, the bearing connecting plate being fixedly connected to the inner ring of the pitch bearing; a three-axis motion mechanism, the three-axis motion mechanism being disposed within the frame body, the three-axis motion mechanism being used to drive a tightening actuator to move in three-dimensional space; a tightening actuator, the tightening actuator being connected to the moving end of the three-axis motion mechanism, the tightening actuator including an electric tightening assembly; and a rotary electrical connection mechanism, the rotary electrical connection mechanism being disposed at the bottom of the frame body, the rotary electrical connection mechanism being used to transmit electrical signals when the gantry frame rotates with the pitch bearing.

[0006] Optionally, the pitch bearing bolt tightening device further includes a marking mechanism, which is connected to the moving end of the three-axis motion mechanism. The marking mechanism includes a rotary drive and a multi-station marking head. The multi-station marking head is provided with at least two nozzles of different colors. The rotary drive drives the multi-station marking head to rotate to switch the different colored nozzles to the working position.

[0007] Optionally, the marking mechanism further includes a linear drive that drives the multi-station marking head to move vertically toward or away from the bolt.

[0008] Optionally, the marking mechanism further includes a fine-tuning component, which is disposed between the multi-station marking head and the three-axis motion mechanism, and is used to manually adjust the position of the multi-station marking head.

[0009] Optionally, the pitch bearing bolt tightening device further includes an imaging mechanism connected to the moving end of the three-axis motion mechanism. The imaging mechanism includes an image acquisition device and a distance detection device. The image acquisition device is used to acquire a position image of the bolt, and the distance detection device is used to detect the distance between the tightening actuator and the bolt.

[0010] Optionally, the imaging mechanism further includes an auxiliary lighting device, which is arranged around the image acquisition device.

[0011] Optionally, the mounting plate base is provided with a mounting interface for mounting a bearing connecting plate, and the bearing connecting plate is provided with a connecting hole adapted to the pitch bearing to be operated.

[0012] Optionally, the electric tightening assembly integrates a torque sensor and an angle sensor, wherein the torque sensor is used to detect the tightening torque and the angle sensor is used to detect the tightening angle.

[0013] Optionally, the tightening actuator further includes a locking mechanism located on the outer periphery of the electric tightening assembly, which is used to restrict the radial movement of the electric tightening assembly during tightening operations.

[0014] Optionally, the three-axis motion mechanism includes a first axis module extending along a first direction, a second axis module extending along a second direction, and a third axis module extending along a third direction. The first direction and the second direction are parallel to the plane where the mounting plate base is located, and the third direction is perpendicular to the plane where the mounting plate base is located.

[0015] An embodiment of this application also provides a pitch bearing bolt tightening system, comprising: a pitch bearing bolt tightening device, the pitch bearing bolt tightening device being as described in any of the preceding claims; and a mobile bearing device, the mobile bearing device comprising a frame support and wheels disposed at the bottom of the frame support, the frame support being provided with a placement platform for supporting the gantry frame.

[0016] An embodiment of this application also provides a method for tightening pitch bearing bolts, using the pitch bearing bolt tightening equipment described in any of the above claims. The method includes the following steps: fixing the gantry frame to the inner ring of the pitch bearing via the bearing connecting plate; driving the inner ring of the pitch bearing to rotate, thereby causing the gantry frame connected to it to rotate synchronously; acquiring the position information of the current target bolt; the three-axis motion mechanism driving the tightening actuator to move above the current target bolt; the tightening actuator descending and performing a tightening operation on the current target bolt; wherein the tightening operation includes pre-tightening treatment and final tightening treatment, the equipment first performs pre-tightening treatment on all target bolts, and then performs final tightening treatment on all target bolts.

[0017] Optionally, the step of obtaining the position information of the current target bolt includes: acquiring a position image of the current target bolt using an image acquisition device; detecting the distance between the tightening actuator and the current target bolt using a distance detection device; and determining the three-dimensional coordinates of the current target bolt based on the position image and the distance.

[0018] Optionally, the method further includes a marking step: while the tightening actuator is performing a tightening operation on the current target bolt, the marking mechanism sprays a mark on the bolt that has been tightened.

[0019] Optionally, in the pre-tightening process, the marking mechanism marks the bolts that have completed pre-tightening with a first color; after the pre-tightening process is completed, the rotary drive drives the multi-station marking head to rotate, switching the nozzle of the second color to the working position; in the final tightening process, the marking mechanism marks the bolts that have completed final tightening with the second color.

[0020] The technical solution provided in this application has at least the following advantages: This application achieves automated tightening of bolts at various positions on the pitch bearing by fixing the bearing connecting plate of the gantry frame to the inner ring of the pitch bearing. This allows the entire tightening device to rotate synchronously with the inner ring of the pitch bearing. Combined with a three-axis motion mechanism driving the tightening actuator to move in three-dimensional space, this improves tightening efficiency and reduces labor intensity. Furthermore, the detachable connection between the bearing connecting plate and the mounting plate base allows for adaptation to different pitch bearing interfaces on various wind turbine hubs by replacing the bearing connecting plate with different specifications, achieving multi-purpose functionality and enhancing the equipment's versatility and flexibility. In addition, a rotating electrical connection mechanism at the bottom of the frame ensures continuous and stable transmission of power and control signals while the equipment rotates 360 degrees with the pitch bearing, eliminating the risk of cable entanglement and breakage, and improving the equipment's reliability and continuous operation capability. Attached Figure Description

[0021] One or more embodiments are illustrated by way of example with corresponding pictures in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this application or in the conventional technology, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of a pitch bearing bolt tightening device provided in an embodiment of this application; Figure 2 This is a schematic diagram of the structure of a pitch bearing bolt tightening device after the gantry frame has been removed, as provided in an embodiment of this application. Figure 3 This is a schematic diagram of the structure of a pitch bearing bolt tightening device after the gantry frame has been removed, as provided in an embodiment of this application. Figure 4 This is a side view of a pitch bearing bolt tightening system provided in an embodiment of this application. Figure 5 This application provides a schematic diagram of the structure of a rotary electrical connection mechanism in a pitch bearing bolt tightening device. Figure 6 This is a schematic diagram of a pitch bearing bolt tightening system provided in an embodiment of this application.

[0023] Explanation of reference numerals in the attached figures: 100. Gantry frame; 110. Frame body; 111. Side door; 1111. Door frame; 1112. Transparent observation window; 112. Status indicator light; 113. Lifting part; 114. Support ear; 120. Mounting plate base; 121. Mounting interface; 130. Bearing connecting plate; 131. Connecting hole; 200. Three-axis motion mechanism; 210. First axis module; 220. Second axis module; 230. Third axis module; 211. First fixing plate; 212. First moving guide rail; 213. First moving unit; 214. First motor; 221. Second fixing plate; 222. Second moving guide rail; 223. Second moving unit; 224. Second motor; 231. Third fixing plate; 232. 1. Third moving guide rail; 2.33. Third moving unit; 2.34. Third motor; 3.00. Tightening actuator; 3.10. Electric tightening assembly; 3.20. Locking mechanism; 4.00. Rotary electrical connection mechanism; 4.10. Slip ring body; 4.20. Flange connector; 5.00. Imaging mechanism; 5.10. Image acquisition device; 5.20. Distance detection device; 5.30. Auxiliary lighting device; 6.00. Marking mechanism; 6.10. Rotary drive component; 6.20. Multi-station marking head; 6.21. Nozzle; 6.30. Linear drive component; 6.40. Fine-tuning assembly; 7.00. Moving load-bearing device; 7.10. Frame support; 7.20. Traveling wheels; 7.30. Placement platform; 7.40. Handrail; 8.00. Electrical control cabinet. Detailed Implementation

[0024] As the background technology reveals, in related technologies, tightening equipment operating with the pitch bearing is prone to cable and air hose entanglement and breakage during rotation. This can lead to equipment malfunction, severely impacting its continuous operating capability and service life. The root cause of this problem lies in the fact that existing rotating equipment generally employs a traditional direct cable connection method. One end of the electrical cable and air hose is fixedly connected to the rotating equipment body, while the other end is fixedly connected to a stationary electrical control cabinet. When the equipment rotates circumferentially with the inner ring of the pitch bearing, the cable and air hose passively follow the equipment's rotation, resulting in torsion. Since pitch bearing bolt tightening typically requires a 360-degree full-circumference rotation of the equipment, and multiple reciprocating rotations are needed in both pre-tightening and final tightening processes to complete the tightening of all bolts on the hub, the torsional stress on the cable and air hose accumulates with each rotation. Traditional direct cable connection methods lack a rotating interface that enables stable transmission of electrical signals and air circuits between rotating and stationary parts. This makes it impossible to decouple rotational motion from electrical transmission, inevitably leading to entanglement and fatigue breakage of cables and air pipes after prolonged continuous operation, which in turn causes equipment failure.

[0025] This application provides a pitch bearing bolt tightening device. By setting a rotating electrical connection mechanism at the bottom of the frame, the device can continuously and stably transmit power, control signals, and air circuits between the rotating device body and the stationary external control cabinet when it rotates 360 degrees with the pitch bearing. This effectively decouples the rotational motion from the electrical transmission, thereby eliminating the accumulation of torsional stress in cables and air pipes caused by the rotation of the device. This solves the problem of cables easily getting tangled and broken in the prior art, significantly improving the reliability and continuous operation capability of the device. At the same time, the bearing connecting plate and the mounting plate base adopt a detachable connection method. By replacing the bearing connecting plate of different specifications, it can be adapted to the pitch bearing interface of different models of wind turbine hubs, realizing multiple uses of one machine and improving the versatility of the device.

[0026] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined. Similarly, "multiple sets" refers to two or more sets (including two sets), and "multiple pieces" refers to two or more pieces (including two pieces).

[0027] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0028] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. In addition, the character " / " in this document generally indicates that the related objects before and after it have an "or" relationship.

[0029] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application. For example, if the device or element in the illustration is inverted, then the element described as "below," "under," "below," or "bottom" of other elements or features will be oriented "above" or "top" of said other elements or features. Therefore, the term "below" may cover both above and below orientation depending on the context in which the term is used, which will be obvious to those skilled in the art. Materials may be oriented in other ways (e.g., rotated 90 degrees, inverted, flipped), and the spatial relative descriptive terms used herein may be interpreted accordingly.

[0030] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0031] In the description of the embodiments of this application, when a component "includes" another component, other components are not excluded unless otherwise stated, and other components may be further included. The formation or provision of a second component above or on a first component, or on the surface of a first component, or on one side of a first component, may include embodiments where the first and second components are in direct contact, and may also include embodiments where an additional component may be present between the first and second components, thereby preventing direct contact between the first and second components. For simplicity and clarity, various components may be drawn at different scales. In the drawings, some layers / components may be omitted for simplicity. Unless otherwise specified, the formation or provision of a second component on the surface of a first component refers to direct contact between the first and second components. The term "component" may refer to a layer, film, region, portion, structure, etc.

[0032] The terminology used in the description of the various embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various embodiments and the appended claims, the term "component" is also intended to include the plural form unless the context clearly indicates otherwise. Components include layers, films, regions, or plates, etc.

[0033] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0034] Figure 1 This is a schematic diagram of a pitch bearing bolt tightening device provided in an embodiment of this application; Figure 2 This is a schematic diagram of the structure of a pitch bearing bolt tightening device after the gantry frame has been removed, as provided in an embodiment of this application. Figure 3 This is a schematic diagram of the structure of a pitch bearing bolt tightening device after the gantry frame has been removed, as provided in an embodiment of this application. Figure 4 This is a schematic diagram of a pitch bearing bolt tightening system provided in an embodiment of this application.

[0035] refer to Figures 1 to 3 The pitch bearing bolt tightening equipment includes: A gantry frame, comprising a frame body, a mounting plate base, and a bearing connecting plate, wherein the mounting plate base is fixed to the frame body, and the bearing connecting plate is detachably connected to the mounting plate base, and the bearing connecting plate is used for fixed connection with the inner ring of a pitch bearing. A three-axis motion mechanism is disposed within the frame, and the three-axis motion mechanism includes a motion end effector that can move in three-dimensional space. A tightening actuator is connected to the moving end, and the tightening actuator includes an electric tightening assembly; A rotating electrical connection mechanism is provided at the bottom of the frame body. The rotating electrical connection mechanism is used to transmit electrical signals when the gantry frame rotates with the pitch bearing.

[0036] This embodiment of the application, by setting a rotating electrical connection mechanism at the bottom of the frame, enables continuous and stable transmission of power, control signals, and air circuits between the rotating equipment body and the stationary external control cabinet when the equipment rotates 360 degrees with the pitch bearing. This effectively decouples rotational motion from electrical transmission, thus preventing the accumulation of torsional stress in cables and air pipes caused by the equipment's rotation. This solves the problem of cables easily tangling and breaking in existing technologies, significantly improving the equipment's reliability and continuous operation capability. Simultaneously, the bearing connecting plate and the mounting plate base are detachably connected, allowing for adaptation to different types of wind turbine hub pitch bearing interfaces by replacing different specifications of the bearing connecting plate, achieving multi-purpose functionality and improving the equipment's versatility.

[0037] The embodiments of this application will be described in more detail below with reference to the accompanying drawings.

[0038] like Figure 1 As shown, the pitch bearing bolt tightening device provided in this application embodiment includes a gantry frame 100, a three-axis motion mechanism 200, a tightening actuator 300, and a rotary electrical connection mechanism 400.

[0039] The gantry frame 100 serves as the core load-bearing and installation foundation for the entire equipment. It reliably secures the entire device to the inner ring of the pitch bearing on the wind turbine hub and rotates with the pitch bearing to complete all bolting operations. The gantry frame 100 includes a frame body 110, a mounting plate base 120, and a bearing connecting plate 130. The frame body 110 is a three-dimensional frame structure formed by welding profiles, used to support functional components such as the three-axis motion mechanism 200 and the tightening actuator 300. The mounting plate base 120 is fixed to the bottom of the frame body 110, providing the mounting foundation for the bearing connecting plate 130. The bearing connecting plate 130 is detachably connected to the mounting plate base 120 and is used to fix the bearing connecting plate 130 to the inner ring of the pitch bearing, ensuring that the entire gantry frame 100 can be reliably fixed to the pitch bearing and rotate synchronously with it. The bearing connecting plate 130 and the mounting plate base 120 are detachably connected. By replacing the bearing connecting plate 130 of different specifications, it can be adapted to the pitch bearing interface of different models of wind turbine hubs, realizing multiple uses of one machine and improving the versatility and flexibility of the equipment.

[0040] The three-axis motion mechanism 200 is housed within the frame 110 and is used to drive the end effector (i.e., the tightening actuator 300) to be precisely positioned and moved in three-dimensional space. The three-axis motion mechanism 200 includes a motion end effector that can move in three-dimensional space. This motion end effector can move linearly in three mutually perpendicular directions, thereby achieving precise alignment of bolts at different positions on the pitch bearing.

[0041] The tightening actuator 300 is connected to the moving end of the three-axis motion mechanism 200, serving as a functional unit for directly performing bolt tightening operations. The tightening actuator 300 includes an electric tightening assembly 310, which can output controlled rotational torque to complete the bolt tightening operation.

[0042] The rotary electrical connection mechanism 400 is located at the bottom of the frame 110 and is used to transmit electrical signals when the gantry frame 100 rotates with the pitch bearing. As a rotary electrical interface, the rotary electrical connection mechanism 400 allows power, control signals, and pneumatic circuits from the external electrical control cabinet to be continuously and stably transmitted to the equipment body when the equipment is rotating 360 degrees, without cable breakage or tangling. This effectively decouples the rotational motion from the electrical transmission, significantly improving the reliability and continuous operation capability of the equipment.

[0043] The frame 110 is welded from square steel bars to ensure overall structural rigidity and withstand the reaction torque generated during tightening operations. The frame 110 has a three-dimensional cage-like structure, forming an internal installation space to accommodate the three-axis motion mechanism 200.

[0044] In some embodiments, a side door 111 is provided on the side of the frame 110. The side door 111 includes a door frame 1111 and a transparent observation window 1112 disposed on the door frame 1111. Specifically, the door frame 1111 is made of sheet metal, and the transparent observation window 1112 is made of transparent acrylic sheet. The side door 111 is connected to the frame 110 by a linkage lock, which facilitates opening and closing. The side door 111 facilitates maintenance and repair of the equipment interior, and the transparent observation window 1112 allows operators to visually observe the internal working status of the equipment during operation, improving the maintainability of the equipment and the visibility of the operation process.

[0045] In some embodiments, the frame 110 is provided with a status indicator light 112. Specifically, the status indicator light 112 is a three-color indicator light, installed on the top of the frame 110, which can intuitively display the operating status of the equipment to the ground operator through different colors and sound signals. For example, green indicates normal operation, yellow indicates warning, and red indicates fault, which facilitates real-time monitoring and abnormal alarm.

[0046] In some embodiments, the frame 110 is provided with a lifting section 113 for connecting to external lifting equipment. Specifically, the lifting section 113 includes multiple eye bolts welded to the top of the frame 110. The multiple eye bolts have a specific height difference to ensure that the equipment can be lifted at a specific angle and accurately installed onto the hub. The lifting section 113 allows the gantry frame 100 to be connected to external lifting equipment, facilitating the lifting of the equipment to the hub position and installation onto the pitch bearing, reducing the difficulty of equipment deployment and the intensity of manual operation.

[0047] The bottom of the frame 110 is also provided with a support ear 114. The support ear 114 is used to stably support the gantry frame 100 on the mobile load-bearing device when it is not in operation, so as to realize the rapid combination and separation of the gantry frame 100 and the mobile load-bearing device.

[0048] like Figure 1 As shown, the mounting plate base 120 is fixedly connected to the bottom of the frame 110, providing a mounting base for the bearing connecting plate 130.

[0049] In some embodiments, the mounting plate base 120 is provided with a mounting interface 121 for mounting a bearing connecting plate 130, and the bearing connecting plate 130 is provided with connecting holes 131 adapted to the pitch bearing to be operated. Specifically, the bearing connecting plate 130 is detachably connected to the mounting interface 121 by bolts. The connecting holes 131 on the bearing connecting plate 130 correspond to the mounting holes on the inner ring of the pitch bearing, and the bearing connecting plate 130 is fixedly connected to the inner ring of the pitch bearing by bolts. By providing a standardized mounting interface 121 on the mounting plate base 120 and using bearing connecting plates 130 with different connecting hole 131 specifications, rapid adaptation and switching of different types of pitch bearings can be achieved. When it is necessary to adapt to pitch bearings with different hole pitches, only the bearing connecting plate 130 of the corresponding specification needs to be replaced, without modifying the main body of the equipment, thus enhancing the versatility and flexibility of the equipment.

[0050] like Figure 4 and Figure 5 As shown, Figure 4 This is a side view of a pitch bearing bolt tightening system provided in an embodiment of this application. Figure 5 This is a schematic diagram of the rotating electrical connection mechanism in a pitch bearing bolt tightening device provided in this application embodiment. The rotating electrical connection mechanism 400 is located at the bottom of the frame 110 and is a key component for solving the cable entanglement problem.

[0051] In some embodiments, the rotary electrical connection mechanism 400 includes a slip ring body 410 and a flange connector 420. The flange connector 420 is fixedly connected to the bottom of the frame 110, and the slip ring body 410 is mounted on the flange connector 420. Specifically, the flange connector 420 is used to reliably fix the slip ring body 410 to the bottom of the frame 110. The slip ring body 410 is a cable slip ring, serving as a rotary electrical interface. It has multiple electrical and pneumatic channels inside. The stator end of the slip ring body 410 is connected to the cables and air pipes of the external electrical control cabinet, and the rotor end of the slip ring body 410 is connected to the electrical cables and air pipes inside the gantry frame 100. When the gantry frame 100 rotates with the pitch bearing, the rotor end of the slip ring body 410 rotates synchronously with the frame 110, while the stator end remains stationary. Electricity, control signals, and pneumatic transmission are transmitted between the rotor end and the stator end through the rotating contacts or channels inside the slip ring body 410, thus decoupling the rotary motion from the electrical transmission. By installing the slip ring body 410 and the flange connector 420 together, the rotary electrical connection mechanism 400 is reliably connected to the frame body 110. The slip ring body 410 can maintain stable transmission of electrical signals and air circuits when the equipment rotates 360 degrees, eliminating the risk of cable breakage and ensuring that the equipment can withstand long-term trouble-free continuous operation.

[0052] like Figure 2 and Figure 3 As shown, the three-axis motion mechanism 200 is the core of spatial positioning and movement in this embodiment of the application, used to drive the end effector to be precisely positioned in three-dimensional space.

[0053] In some embodiments, the three-axis motion mechanism 200 includes a first axis module 210 extending along a first direction, a second axis module 220 extending along a second direction, and a third axis module 230 extending along a third direction. The first direction, the second direction, and the third direction intersect and are perpendicular to each other, forming a gantry-type three-axis linear guide moving structure, which realizes the precise positioning and movement of the tightening actuator 300 in three-dimensional space, and meets the operational requirements for bolts at different positions and heights on the pitch bearing.

[0054] In some embodiments, the first axis module 210, the second axis module 220, and the third axis module 230 each include a linear drive assembly and a linear guide rail, wherein the linear drive assembly is used to drive the slider to slide along the linear guide rail. Figure 3 As shown, the tightening actuator 300 is connected to the moving end of the three-axis motion mechanism 200, specifically to the lower end face of the third moving unit 233 of the third axis module 230, serving as a functional unit for directly performing bolt tightening operations.

[0055] The first axis module 210 includes a first fixed plate 211, a first movable guide rail 212, a first movable unit 213, and a first motor 214. The first fixed plate 211 is fixedly connected to the frame body 110. The first movable guide rail 212 extends along a first direction and is fixedly mounted on the first fixed plate 211. The first movable unit 213 is slidably mounted on the first movable guide rail 212 along the first direction. The first motor 214 drives the first movable unit 213 to slide along the first direction through the first movable guide rail 212, thereby realizing the linear movement of the output end of the first axis module 210 (i.e., the first movable unit 213) along the first direction.

[0056] The second axis module 220 includes a second fixed plate 221, a second moving guide rail 222, a second moving unit 223, and a second motor 224. The second fixed plate 221 is fixedly connected to the first moving unit 213. The second moving guide rail 222 extends along a second direction and is fixedly mounted on the second fixed plate 221. The second moving unit 223 is slidably mounted on the second moving guide rail 222 along the second direction. The second motor 224 drives the second moving unit 223 to slide along the second direction via the second moving guide rail 222. This achieves linear motion at the output end of the second axis module 220 (i.e., the second moving unit 223). Because the second fixed plate 221 is fixedly connected to the first moving unit 213, the second axis module 220 can move as a whole along the first moving unit 213 in the first direction.

[0057] The third axis module 230 includes a third fixed plate 231, a third moving guide rail 232, a third moving unit 233, and a third motor 234. The third fixed plate 231 is fixedly connected to the second moving unit 223. The third moving guide rail 232 extends along a third direction and is fixedly mounted on the third fixed plate 231. The third moving unit 233 is slidably mounted on the third moving guide rail 232 along a third direction. The third motor 234 drives the third moving unit 233 to slide along the third direction through the third moving guide rail 232. This achieves linear motion at the output end of the third axis module 230 (i.e., the third moving unit 233). Since the third fixed plate 231 is fixedly connected to the second moving unit 223, the third axis module 230 can move as a whole along a second direction with the second moving unit 223. The lower end face of the third moving unit 233 is used to fix end effectors such as the tightening actuator 300, the imaging mechanism 500, and the marking mechanism 600. The third moving unit 233 is the moving end of the three-axis motion mechanism 200.

[0058] The first axis module 210, the second axis module 220, and the third axis module 230 are connected in series to form a gantry-type three-axis linear guide moving structure, enabling the tightening actuator 300 to be precisely positioned and moved in three-dimensional space. Each axis module adopts a servo motor-driven ball screw transmission method, combined with the guiding effect of linear guides, to ensure the positioning accuracy and repeatability of the tightening actuator 300, and to withstand the axial tension and working torque during tightening operations.

[0059] The tightening actuator 300 includes an electric tightening assembly 310. The electric tightening assembly 310 is a high-precision servo tightening shaft driven by a servo motor, which can output precise and controlled rotational torque and angle, and strictly implement the process parameter requirements for pre-tightening and final tightening.

[0060] In some embodiments, the electric tightening assembly 310 integrates a torque sensor and an angle sensor. The torque sensor detects the tightening torque, and the angle sensor detects the tightening angle. Specifically, the torque sensor is located on the output shaft of the electric tightening assembly 310 and can detect the torque value applied to the bolt during tightening in real time; the angle sensor is located on the drive end of the electric tightening assembly 310 and can detect the rotation angle of the output shaft during tightening in real time. The integrated torque and angle sensors can detect and record tightening torque and angle data in real time. When the tightening torque and angle reach preset process parameter values, the electric tightening assembly 310 automatically stops operating, ensuring the consistency of tightening quality for each bolt and enabling traceability of tightening data.

[0061] In some embodiments, the tightening actuator 300 further includes a locking mechanism 320, which is disposed on the outer periphery of the electric tightening assembly 310. The locking mechanism 320 is used to restrict the radial movement of the electric tightening assembly 310 during tightening operations. Specifically, the locking mechanism 320 is a gun-body locking mechanism, which covers the outer periphery of the electric tightening assembly 310 and is fixedly connected to the third moving unit, securely mounting the electric tightening assembly 310 on the three-axis motion mechanism 200. The locking mechanism 320 can securely fix the electric tightening assembly 310 during tightening operations, restricting its radial movement and wobbling, ensuring stability during tightening operations, avoiding deviation caused by reaction torque, and improving tightening quality.

[0062] like Figure 3 As shown, the pitch bearing bolt tightening device also includes an imaging mechanism 500, which serves as the device's visual input unit for achieving high-precision bolt identification and guided positioning.

[0063] In some embodiments, the imaging mechanism 500 is connected to the moving end of the three-axis motion mechanism 200. The imaging mechanism 500 includes an image acquisition device 510 and a distance detection device 520. The image acquisition device 510 is used to acquire position images of the bolt, and the distance detection device 520 is used to detect the distance between the tightening actuator 300 and the bolt. Specifically, the image acquisition device 510 includes a high-resolution industrial camera and its bracket. The industrial camera is fixedly mounted on the moving end of the three-axis motion mechanism 200, with its lens facing the work area to capture real-time images of the bolt. The distance detection device 520 is a laser rangefinder used to accurately measure the distance between the image acquisition device 510 and the workpiece. By acquiring the position image of the bolt through the image acquisition device 510 and combining it with a visual recognition algorithm to determine the position coordinates of the bolt head in the image plane, and simultaneously detecting the distance information between the bolt and the distance detection device 520 to assist in focusing and depth positioning, the three-dimensional spatial coordinates of the bolt are determined, providing data support for the precise motion control of the three-axis motion mechanism 200 and improving the positioning accuracy of the tightening operation.

[0064] In some embodiments, the imaging mechanism 500 further includes an auxiliary lighting device 530, which is disposed around the image acquisition device 510. Specifically, the auxiliary lighting device 530 uses a ring-shaped LED light source and is installed around the industrial camera lens, which can provide stable and uniform lighting conditions for the image acquisition device 510, overcome the problem of poor lighting inside the wheel hub, ensure that the acquired image is clear and has high contrast, and improve the reliability and accuracy of visual positioning.

[0065] like Figure 3 As shown, the pitch bearing bolt tightening equipment also includes a marking mechanism 600, which innovatively realizes the function of two-color scribing marking in the automated tightening process.

[0066] In some embodiments, the marking mechanism 600 is connected to the moving end of the three-axis motion mechanism 200. The marking mechanism 600 includes a rotary drive 610 and a multi-station marking head 620. The multi-station marking head 620 is provided with at least two nozzles 621 of different colors. The rotary drive 610 drives the multi-station marking head 620 to rotate to switch the different colored nozzles 621 to the working position. Specifically, the rotary drive 610 is a rotary cylinder, and the multi-station marking head 620 is a double-headed spray gun. The double-headed spray gun is equipped with two nozzles 621, which are respectively loaded with pre-tightening marking ink and final tightening marking ink. The rotary cylinder drives the double-headed spray gun to rotate 180 degrees, which can quickly and automatically switch between the two colors, rotating the corresponding colored nozzle 621 to the working position facing the bolt. The multi-station marking head 620 is driven to rotate by the rotary drive component 610, which can automatically switch between different colored nozzles 621 between the pre-tightening and final tightening processes, realizing automatic two-color marking without manual intervention. This perfectly meets the process requirements of different colored markings during the two tightening processes, improving marking efficiency and the degree of automation.

[0067] In some embodiments, the marking mechanism 600 further includes a linear drive 630, which drives the multi-station marking head 620 to move vertically closer to or further away from the bolt. Specifically, the linear drive 630 is a movable cylinder, the cylinder body of which is fixedly mounted to the moving end of the three-axis motion mechanism 200. The piston rod of the movable cylinder is connected to the multi-station marking head 620, driving the multi-station marking head 620 to extend and retract vertically. By driving the multi-station marking head 620 to move vertically via the linear drive 630, the spraying requirements of bolts of different heights or bolts with protective sleeves can be accommodated. For standard height bolts, the movable cylinder remains retracted; if the bolt has a protective sleeve that increases the bolt head height, the movable cylinder automatically extends to ensure that the nozzle 621 reaches the bolt root, guaranteeing optimal spraying distance and marking effect.

[0068] In some embodiments, the marking mechanism 600 further includes a fine-tuning component 640, which is disposed between the multi-station marking head 620 and the three-axis motion mechanism 200. The fine-tuning component 640 is used to manually adjust the position of the multi-station marking head 620. Specifically, the fine-tuning component 640 is a nozzle fine-tuning assembly, which adopts a three-axis manual precision slide structure, enabling fine position adjustment of the multi-station marking head 620 in three directions: a first direction, a second direction, and a third direction. The fine-tuning component 640 allows for fine position calibration of the multi-station marking head 620, compensating for installation errors and part tolerances, ensuring accurate and clear marking positions, and improving the precision of the scribing marks.

[0069] In some embodiments, the imaging mechanism 500 further includes a bolt type recognition module. This module automatically identifies the bolt specifications based on the bolt image acquired by the image acquisition device 510, and automatically calls the corresponding tightening process parameters based on the recognition result, achieving adaptive tightening of bolts of different specifications. This embodiment eliminates the need for manual switching of process procedures for different bolt specifications, further improving operational efficiency and intelligence.

[0070] Another embodiment of this application also provides a pitch bearing bolt tightening system, such as Figure 4 , Figure 6 As shown, Figure 6 A schematic diagram of a pitch bearing bolt tightening system according to an embodiment of this application is shown. The system includes a pitch bearing bolt tightening device and a movable bearing device 700. The pitch bearing bolt tightening device is the same as the pitch bearing bolt tightening device provided in the above embodiment, and will not be described again here.

[0071] The mobile support device 700 serves as a mobile base for the equipment, facilitating convenient handling and on-site positioning of the entire tightening equipment. The mobile support device 700 includes a frame support 710 and wheels 720 located at the bottom of the frame support 710. The frame support 710 is equipped with a placement platform 730 for supporting the gantry frame 100.

[0072] The frame support 710 is welded from square steel bars, ensuring structural rigidity and stably supporting the weight of the gantry frame 100 and its accessories. The traveling wheels 720 are installed at the bottom of the frame support 710. These wheels are fenders and have both moving and locking functions, facilitating flexible movement and precise positioning of the equipment in the workshop or on-site. Once the equipment is in position, the traveling wheels 720 can be locked to prevent slippage. The placement platform 730 is located on top of the frame support 710 and is used to support the gantry frame 100. The gantry frame 100 is connected to the placement platform 730 via its bottom support lugs 114, enabling rapid assembly and disassembly of the gantry frame 100 and the mobile support device 700.

[0073] This embodiment of the application, by setting up a mobile support device 700, allows the gantry frame 100 to be placed on the placement platform 730 of the mobile support device 700 when not in operation. With the help of the traveling wheels 720, the entire equipment can be flexibly moved and precisely positioned in the workshop or on-site, forming a split-type mother-daughter machine structure. When tightening operations are required, the gantry frame 100 is lifted from the mobile support device 700 using hoisting equipment and installed onto the inner ring of the pitch bearing; after the operation is completed, the gantry frame 100 is lifted back onto the mobile support device 700 for transport. This split design significantly reduces the weight of individual components, facilitates manual operation and equipment handling, and reduces the labor intensity and operational risks for operators.

[0074] In one specific embodiment, the mobile support device 700 further includes a handrail 740 disposed on the frame support 710. Specifically, the handrail 740 is disposed on one side of the frame support 710 and has a U-shaped or straight rod structure, making it easy for operators to grip. The handrail 740 facilitates the operation of pushing and pulling the mobile support device 700, making equipment transportation more labor-saving and safer.

[0075] In addition, such as Figure 1 As shown, the mobile support unit 700 also has an area on its frame support 710 for placing an electrical control cabinet 800. The electrical control cabinet 800 provides power and control signals to the pitch bearing bolt tightening equipment. The electrical control cabinet 800 is connected to the electrical wiring within the gantry frame 100 via a rotary electrical connection mechanism 400. The mobile support unit 700 may also have an area for placing a coding machine cabinet, which provides ink supply to the marking mechanism 600. By integrating the electrical control cabinet 800 and the coding machine cabinet onto the mobile support unit 700, the entire system is modularized and integrated, facilitating overall transport and deployment.

[0076] Accordingly, another embodiment of this application also provides a method for tightening pitch bearing bolts, which is performed using the pitch bearing bolt tightening equipment provided in the above embodiments. The pitch bearing bolt tightening method provided in the embodiments of this application will be described in detail below with reference to the accompanying drawings. For parts that are the same as or corresponding to the aforementioned equipment embodiments, please refer to the corresponding descriptions in the aforementioned embodiments; they will not be elaborated upon hereafter.

[0077] The method for tightening pitch bearing bolts includes the following steps: Step S100: Fix the gantry frame to the inner ring of the pitch bearing via the bearing connecting plate.

[0078] Step S200: Drive the inner ring of the pitch bearing to rotate, thereby causing the gantry frame connected to it to rotate synchronously.

[0079] Step S300: Obtain the position information of the current target bolt.

[0080] Step S400: The three-axis motion mechanism drives the tightening actuator to move above the current target bolt.

[0081] Step S500: The tightening actuator descends and performs a tightening operation on the current target bolt.

[0082] This embodiment of the application achieves an automated tightening process for pitch bearing bolts by fixing the gantry frame to the inner ring of the pitch bearing and rotating it synchronously, and using a three-axis motion mechanism to drive the tightening actuator to move to the target bolt position for tightening. Furthermore, the step-by-step operation of pre-tightening all target bolts before final tightening conforms to the bolt tightening process specifications, ensuring tightening quality and uniformity of preload.

[0083] In step S100, the operator uses the mobile support device 700 to transport the entire set of equipment to the wind turbine hub. The lifting section 113 on top of the gantry frame 100 is connected via external hoisting equipment, and the gantry frame 100 is lifted and moved to the hub position. Based on the model of the pitch bearing to be operated, a matching bearing connecting plate 130 is pre-installed on the mounting plate base 120. The connecting holes 131 on the bearing connecting plate 130 are aligned with the mounting holes on the inner ring of the pitch bearing. The bearing connecting plate 130 is then fixedly connected to the inner ring of the pitch bearing using bolts, ensuring that the gantry frame 100 is reliably fixed to the pitch bearing.

[0084] In step S200, the inner ring of the pitch bearing is driven to rotate, causing the gantry frame connected to it to rotate synchronously. After the system is started, the wind turbine pitch motor drives the inner ring of the pitch bearing to rotate. Since the gantry frame 100 is fixedly connected to the inner ring of the pitch bearing through the bearing connecting plate 130, the gantry frame 100 rotates synchronously with the inner ring of the pitch bearing. During the rotation, the rotating electrical connection mechanism 400 maintains stable transmission of power, control signals, and air circuits to ensure normal operation of the equipment.

[0085] In step S300, when the gantry frame 100 rotates to the area above the target bolt, the imaging mechanism 500 identifies and locates the current target bolt. The image acquisition device 510 acquires a position image of the target bolt and determines the position coordinates of the bolt head in the image plane through a visual recognition algorithm; the distance detection device 520 detects the distance information between itself and the target bolt; based on the position image and the distance information, the three-dimensional spatial coordinates of the current target bolt are calculated and determined.

[0086] In step S400, based on the three-dimensional coordinates of the target bolt obtained in step S300, the three-axis motion mechanism 200 controls the first axis module 210, the second axis module 220 and the third axis module 230 to move in a coordinated manner, so as to precisely move the tightening actuator 300 to the position directly above the current target bolt, thus completing the alignment before the tightening operation.

[0087] In step S500, the third axis module 230 of the three-axis motion mechanism 200 drives the tightening actuator 300 to descend vertically, causing the sleeve of the electric tightening assembly 310 to engage with the bolt head. The electric tightening assembly 310 then starts and outputs rotational torque to tighten the current target bolt. After the tightening operation is completed, the third axis module 230 drives the tightening actuator 300 to rise and retract, and the three-axis motion mechanism 200 resets. Subsequently, the pitch bearing continues to rotate, sending the gantry frame 100 to the next bolt station. Steps S300 to S500 are repeated until all target bolts are tightened.

[0088] The tightening process includes pre-tightening and final tightening. The equipment first performs pre-tightening on all target bolts, followed by final tightening. Pre-tightening uses a lower target torque value to ensure even force distribution and initial positioning of all bolts; final tightening uses the final target torque value to ensure all bolts reach the required preload. This step-by-step approach conforms to bolt tightening specifications, ensuring tightening quality and uniform preload, and avoiding uneven stress distribution caused by tightening all bolts at once.

[0089] In some embodiments, step S300, the step of obtaining the position information of the current target bolt, includes: acquiring a position image of the current target bolt using an image acquisition device 510; detecting the distance between the tightening actuator 300 and the current target bolt using a distance detection device 520; and determining the three-dimensional coordinates of the current target bolt based on the position image and the distance. Through the combination of image acquisition and distance detection, the three-dimensional spatial coordinates of the target bolt can be accurately obtained, providing a basis for the precise motion control of the three-axis motion mechanism 200 and improving the positioning accuracy of the tightening operation.

[0090] In some embodiments, the pitch bearing bolt tightening method further includes a marking step: while the tightening actuator 300 performs the tightening operation on the current target bolt, the marking mechanism 600 sprays a mark on the bolt that has been tightened.

[0091] Specifically, both the marking mechanism 600 and the tightening actuator 300 are mounted at the moving end of the three-axis motion mechanism 200, with a certain spatial offset between them. When the three-axis motion mechanism 200 moves the tightening actuator 300 above the current target bolt, the marking mechanism 600 is positioned precisely above the bolt that has already been tightened previously. While the tightening actuator 300 is tightening the current target bolt, the nozzle 621 of the marking mechanism 600 is aimed at the bolt that has already been tightened, spraying marking ink to form a scribing mark between the bolt head and the connecting surface. The tightening and marking operations are performed in parallel, marking the bolt that has already been tightened while the current bolt is being tightened, making full use of the tightening time for marking, improving overall work efficiency and shortening the work cycle of a single bolt.

[0092] In some embodiments, during the pre-tightening process, the marking mechanism 600 marks the bolts that have completed pre-tightening with a first color; after the pre-tightening process is completed, the rotary drive 610 drives the multi-station marking head 620 to rotate, switching the nozzle 621 of the second color to the working position; during the final tightening process, the marking mechanism 600 marks the bolts that have completed final tightening with a second color.

[0093] Specifically, during the pre-tightening process of all target bolts, the first-color nozzle 621 of the marking mechanism 600 is in the working position, spraying a first-color marking, such as white, onto each pre-tightened bolt. After the pre-tightening of all target bolts is completed, the rotary drive 610 drives the multi-station marking head 620 to rotate 180 degrees, switching the second-color nozzle 621 to the working position facing the bolt. During the final tightening process of all target bolts, the second-color nozzle 621 of the marking mechanism 600 sprays a second-color marking, such as red, onto each final-tightened bolt. This marking covers or is adjacent to the first-color marking used during pre-tightening. By automatically switching the color of the nozzle 621 of the multi-station marking head 620 through the rotary drive 610, the process requirement of using different colors for pre-tightening and final tightening is achieved. This allows subsequent quality inspectors to visually determine whether the bolts have completed all tightening processes by the marking color, eliminating the need for manual color changing and improving marking efficiency and automation.

[0094] Those skilled in the art will understand that the above embodiments are specific examples of implementing this application, and in practical applications, various changes in form and detail can be made without departing from the spirit and scope of this application. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of this application; therefore, the scope of protection of this application should be determined by the scope defined in the claims.

Claims

1. A pitch bearing bolt tightening device, characterized in that, include: A gantry frame, comprising a frame body, a mounting plate base, and a bearing connecting plate, wherein the mounting plate base is fixed to the frame body, and the bearing connecting plate is detachably connected to the mounting plate base, and the bearing connecting plate is used for fixed connection with the inner ring of a pitch bearing. A three-axis motion mechanism is disposed within the frame, and the three-axis motion mechanism includes a motion end effector that can move in three-dimensional space. A tightening actuator is connected to the moving end, and the tightening actuator includes an electric tightening assembly; A rotating electrical connection mechanism is provided at the bottom of the frame body. The rotating electrical connection mechanism is used to transmit electrical signals when the gantry frame rotates with the pitch bearing.

2. The pitch bearing bolt tightening device according to claim 1, characterized in that, It also includes a marking mechanism, which is connected to the moving end of the three-axis motion mechanism. The marking mechanism includes a rotary drive and a multi-station marking head. The multi-station marking head is provided with at least two nozzles of different colors. The rotary drive drives the multi-station marking head to rotate to switch the different colored nozzles to the working position.

3. The pitch bearing bolt tightening device according to claim 1, characterized in that, It also includes an imaging mechanism connected to the moving end of the three-axis motion mechanism. The imaging mechanism includes an image acquisition device and a distance detection device. The image acquisition device is used to acquire position images of the bolt, and the distance detection device is used to detect the distance between the tightening actuator and the bolt.

4. The pitch bearing bolt tightening device according to claim 1, characterized in that, The electric tightening assembly integrates a torque sensor and an angle sensor. The torque sensor is used to detect the tightening torque, and the angle sensor is used to detect the tightening angle.

5. The pitch bearing bolt tightening device according to claim 1, characterized in that, The three-axis motion mechanism includes a first axis module extending along a first direction, a second axis module extending along a second direction, and a third axis module extending along a third direction. The second axis module is installed at the output end of the first axis module, and the third axis module is installed at the output end of the second axis module. The first direction, the second direction, and the third direction intersect and are perpendicular to each other.

6. The pitch bearing bolt tightening device according to claim 1, characterized in that, The rotary electrical connection mechanism includes a slip ring body and a flange connector. The flange connector is fixedly connected to the bottom of the frame body, and the slip ring body is mounted on the flange connector.

7. A pitch bearing bolt tightening system, characterized in that, include: A pitch bearing bolt tightening device, as described in any one of claims 1 to 6; A mobile support device, comprising a frame support and wheels located at the bottom of the frame support, wherein the frame support is provided with a placement platform for supporting the gantry frame.

8. A method for tightening pitch bearing bolts, characterized in that, The method using the pitch bearing bolt tightening equipment according to any one of claims 1 to 6 includes the following steps: The gantry frame is fixedly connected to the inner ring of the pitch bearing via the bearing connecting plate; The inner ring of the pitch bearing is driven to rotate, which in turn causes the gantry frame connected to it to rotate synchronously. Obtain the current position information of the target bolt; The three-axis motion mechanism drives the tightening actuator to move above the current target bolt; The tightening actuator descends and performs a tightening operation on the current target bolt; The tightening operation includes pre-tightening and final tightening. The equipment first performs pre-tightening on all target bolts, and then performs final tightening on all target bolts.

9. The method for tightening pitch bearing bolts according to claim 8, characterized in that, The method further includes a marking step: While the tightening actuator is tightening the current target bolt, the marking mechanism sprays a mark on the bolt that has been tightened.

10. The method for tightening pitch bearing bolts according to claim 9, characterized in that: In the pre-tightening process, the marking mechanism marks the bolts that have been pre-tightened using a first color; After the pre-tightening process is completed, the rotary drive drives the multi-station marking head to rotate, switching the nozzle of the second color to the working position; In the final tightening process, the marking mechanism uses the second color to mark the bolts that have been finally tightened.

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