Precise lead screw assembly running-in device and running-in method

Abstract

A precise lead screw assembly running-in device and a running-in method belong to the field of precise machinery manufacturing, and are characterized by comprising a servo motor, a torque sensor, a nut, a tailstock assembly, a retainer assembly and a servo electric cylinder. The servo motor provides an accurate rotating speed; the linear guide rail ensures the coaxiality of the nut and the screw rod in the running-in process; meanwhile, the tension and pressure sensor serves as detection feedback of loading force, and the load can be visually presented; a torque sensor is used for detecting the running-in torque, and whether the running-in process is qualified or not is automatically judged according to the torque at the initial stage and the final stage of running-in; the temperature sensor monitors the temperature change of the nut in real time, prevents the lead screw assembly from being excessively abraded in the running-in process at any time, and achieves the temperature limiting protection function. The running-in stroke of the lead screw assembly is accurately controlled through the linear displacement sensor; the running-in device is stable and reliable in structure, the running-in method is controllable in control precision, operation is easy, the running-in processing efficiency of the lead screw can be greatly improved, and the running-in device is suitable for application and popularization.

Description

Technical Field

[0001] The present invention belongs to the field of precision machinery manufacturing, and in particular relates to a precision screw assembly running-in device and a running-in method. Background Art

[0002] Lead screws are core components of mechanical transmission systems. They convert rotational motion into linear motion through threaded engagement, offering high-precision positioning and efficient force transmission. In aviation, lead screw assemblies are used to control key control surfaces such as elevators, rudders, and flaps. Their accuracy directly impacts the stability and responsiveness of flight attitude control.

[0003] After machining, a new lead screw may have microscopic surface irregularities, such as machined textures, tiny bumps, or depressions. These can easily lead to the following problems if not fully run-in: Increased wear: Rough surfaces increase local contact stress, accelerating material separation, especially during high-frequency aviation motion. Reduced precision: Initial wear increases backlash, causing servo positioning errors to exceed allowable limits. Noise and vibration: Uneven surfaces increase frictional noise, which, coupled with aircraft vibrations, can cause resonance.

[0004] Traditional run-in methods often rely on manual testing or direct installation and operation. This can lead to localized over-running due to uneven load distribution, and the run-in effect cannot be quantified. Furthermore, a lack of specialized equipment and standardized run-in tables results in inconsistent run-in quality, low efficiency, and difficulty ensuring run-in quality. Summary of the Invention

[0005] The present invention aims to solve the above problems and provide a precision screw assembly running-in device and running-in method that can efficiently and accurately run-in the screw according to preset parameters.

[0006] In a first aspect, the present invention provides a precision screw assembly running-in device, comprising a servo motor, a torque sensor, a first bearing seat, a nut, a tailstock assembly, a retaining frame assembly, and a servo electric cylinder; The output end of the servo motor is connected to one end of the torque sensor through a first coupling; the other end of the torque sensor is connected to the input end of the first bearing seat through a second coupling; A three-jaw chuck is installed at the output end of the first bearing seat; The nut is fixedly arranged on the nut fixing assembly; The retainer assembly is in the shape of a frame; the nut fixing assembly is arranged at the front end of the retainer assembly; an external threaded rod end joint bearing is arranged at the rear end of the retainer assembly; The tailstock assembly is disposed in the frame of the retaining frame assembly; the tailstock assembly includes a servo linear drive, a second bearing seat, and a top spindle; the second bearing seat is disposed on the servo linear drive; the top spindle is disposed in the second bearing seat; The servo motor, the first bearing seat, the three-jaw chuck and the top spindle are coaxially arranged; A tension and pressure sensor is provided between the external threaded rod end joint bearing and the servo electric cylinder; one end of the tension and pressure sensor is connected to the external threaded rod end joint shaft via a connecting fork; and the other end is connected to the servo electric cylinder; Both sides of the cage assembly are provided with linear guide rails; both sides of the cage assembly are provided with guide rail connecting blocks; the cage assembly is connected to the linear guide rails via the guide rail connecting blocks; A linear displacement sensor is provided on one side of the servo electric cylinder; the telescopic end of the servo displacement sensor is connected to the tail end of the aforementioned retaining frame assembly.

[0007] When running-in the screw, use a three-jaw chuck to clamp one end of the screw to be run-in. A process hole is preset on the other end face of the screw. The servo linear drive in the tailstock assembly drives the second bearing seat to approach the end face of the other shaft end of the screw. The top shaft presses against the hole on the other end face of the screw shaft as a support for the other end face of the screw shaft. At this time, the servo motor, bearing seat, three-jaw chuck, and top shaft of the tailstock assembly are coaxial, and the screw is driven to rotate by the servo motor for running-in.

[0008] Furthermore, the precision screw assembly running-in device of the present invention is characterized in that: the nut fixing assembly includes a nut assembly base, a nut pressing plate and a temperature sensor; The base of the nut assembly is provided with a slot for placing the nut; The nut pressing plate is fixedly arranged on the nut assembly base; A threaded hole is provided at the bottom of the base of the nut assembly, and the temperature sensor is fixed through the threaded hole; the end face of the temperature sensor can touch the shaft surface of the nut.

[0009] During the screw run-in process, the nut and nut-fixing assembly become one, and the nut moves linearly along the linear guide along with the retaining frame assembly. The end face of the temperature sensor contacts the shaft surface of the nut to monitor the temperature change of the nut during the run-in process.

[0010] Furthermore, in the precision screw assembly running-in device of the present invention, the retaining frame assembly includes a fixing plate at the front end, retaining frames on both sides, and a force application plate at the rear end; the fixing plate, retaining frame, and force application plate are connected end to end to form a frame; Guide rail connecting blocks are arranged on both sides of the fixing plate; the aforementioned nut fixing assembly is arranged on the fixing plate; and the external threaded rod end joint bearing is arranged on the force application plate.

[0011] Furthermore, in the precision screw assembly running-in device of the present invention, a slider is provided on the guide rail of the linear guide rail; the guide rail connecting block is fixedly connected to the slider; the retaining frame assembly is fixed to the upper plane of the slider on both sides through the guide rail connecting block, and can move linearly along the linear guide rail; The guide rail is provided with two limit switches, one at each end of the guide rail; The front end of the guide rail connecting block is provided with a switch touch plate for triggering the limit switch; when the nut reaches the limit position on both sides, the switch touch plate will trigger the limit switch, forcing the running-in device to stop.

[0012] Furthermore, in the precision screw assembly running-in device described in the present invention, a laser displacement sensor is provided on one side of the aforementioned three-meat chuck; the laser beam of the laser displacement sensor is directly irradiated on the screw shaft to be run-in, and is used to detect the radial runout of the screw during clamping, thereby determining whether the screw is correctly clamped.

[0013] Furthermore, in the precision screw assembly running-in device of the present invention, the servo motor and the servo electric cylinder are fixedly arranged on the servo motor fixing seat and the servo electric cylinder fixing seat respectively; by setting the fixing seat, the stability of the servo motor and the servo electric cylinder can be effectively improved.

[0014] Furthermore, the precision screw assembly running-in device of the present invention further includes a host computer; the servo motor, servo electric cylinder, torque sensor, laser displacement sensor, tension and pressure sensor, linear displacement sensor, and limit switch are all electrically connected to the host computer. The host computer collects sensor signals and sends control signals to the servo motor and servo electric cylinder.

[0015] In a second aspect, the present invention provides a running-in method for the precision screw assembly running-in device according to the first aspect, comprising: Clamp the screw; clamp one end of the screw to be run-in by a three-jaw chuck; pre-machine a process hole on the other end face of the screw to be run-in; after the screw to be run-in passes through the nut, the top shaft presses against the process hole on the other end face of the screw shaft; After the screw rod to be run-in is clamped, set the load value, load direction, loading time, screw nut temperature upper limit, screw nut temperature lower limit, and torque judgment value through the host computer; The host computer sends a signal to control the servo electric cylinder to load, and the nut is subjected to the load; the host computer collects the value of the tension and pressure sensor. When the set load is reached, the host computer controls the servo electric cylinder to stop loading. At this time, the load on the nut reaches the set value; The host computer sends a signal to drive the servo motor to work, and the product running-in begins. During the running-in work, the tension and pressure sensor monitors the axial load force provided by the servo electric cylinder in real time. If it exceeds the limit, the host computer sends a command to control the extension and contraction of the servo electric cylinder in a closed loop based on the monitored axial load force, ensuring that the provided axial load force is consistent in real time.

[0016] At the beginning of the running-in, the detection value of the torque sensor is recorded as the initial torque of the screw running-in. After the running-in time is reached, the detection value of the torque sensor is recorded and the running-in result is automatically judged. If the torque value does not reach the set value, the running-in process is repeated until the set torque value is reached. The running-in process is judged to be qualified and the running-in process is stopped. During the running-in process, the temperature sensor monitors the temperature rise of the nut in real time. When the set upper limit is reached, the equipment automatically stops. When the temperature of the nut drops to the lower limit, the equipment automatically starts the running-in work.

[0017] The precision screw assembly running-in device and running-in method described in the present invention provide precise rotation speed through a servo motor; the coaxiality of the nut and the screw during the running-in process is ensured by setting a linear guide rail; at the same time, a tension and pressure sensor is used as a detection feedback of the loading force to intuitively present the load; a torque sensor is used as a torque detection for running-in, and the torque size at the beginning and end of the running-in period is used to automatically judge whether the running-in process is qualified; the temperature change of the nut is monitored in real time by a temperature sensor to prevent excessive wear of the screw assembly during the running-in process at any time, thereby realizing the temperature limit protection function; the running-in stroke of the screw assembly is accurately controlled by a linear displacement sensor; the running-in device has a stable and reliable structure, the running-in method has controllable control accuracy, and is simple to operate, which can greatly improve the running-in processing efficiency of the screw and is suitable for popularization and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic structural diagram of a precision screw assembly running-in device according to an embodiment of the present invention; Figure 2 This is a schematic structural diagram of a nut fixing assembly according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the bottom structure of the nut fixing assembly according to an embodiment of the present invention; Figure 4 This is a schematic structural diagram of the tailstock assembly according to an embodiment of the present invention; Figure 5 This is a schematic structural diagram of a retainer assembly according to an embodiment of the present invention; Figure 6 Schematic diagram of the implementation of the precision screw assembly running-in method according to an embodiment of the present invention; Among them, 1- workbench, 2- servo motor, 3- servo motor fixed seat, 4- first coupling, 5- torque sensor, 6- second coupling, 7- first bearing seat, 8- three-jaw chuck, 9- laser displacement sensor, 10- screw rod, 11- nut, 12- nut fixing assembly, 13- tailstock assembly, 14- cage assembly, 15- external threaded rod end joint bearing, 16- connecting fork, 17- tension and pressure sensor, 18- servo electric cylinder fixed seat, 19- servo electric cylinder, 20- electric cylinder pad, 21 -Linear displacement sensor, 22-Linear guide, 23-Slider, 24-First limit switch, 25-Switch touch plate, 26-Second limit switch, 1201-Nut assembly base, 1202-Nut pressure plate, 1203-Butterfly nut, 1204-Butterfly bolt, 1205-Temperature sensor, 1301-Servo linear drive, 1302-Second bearing seat, 1303-Top shaft, 1401-Fixed plate, 1402-Cage, 1403-Force plate, 1404-Guide rail connecting block. DETAILED DESCRIPTION

[0019] The precision screw assembly running-in device and running-in method of the present invention are described in detail below with reference to the accompanying drawings and embodiments.

[0020] Example 1 This embodiment discloses a precision screw assembly running-in device, such as Figure 1 As shown, it includes a servo motor 2, a torque sensor 5, a first bearing seat 7, a nut 11, a tailstock assembly 13, a retaining frame assembly 14 and a servo electric cylinder 19; the output end of the servo motor 2 is connected to one end of the torque sensor 5 through a first coupling 4; the other end of the torque sensor 5 is connected to the input end of the aforementioned first bearing seat 7 through a second coupling 6.

[0021] In the embodiment of the present disclosure, the precision screw assembly running-in device is arranged on a workbench 1. The output end of the first bearing seat 7 is mounted with a three-jaw chuck 8; the nut 11 is fixedly mounted on the nut fixing assembly 12; the retaining frame assembly 14 is in the shape of a frame; the nut fixing assembly 12 is arranged at the front end of the retaining frame assembly 14; an externally threaded rod end joint bearing 15 is arranged at the rear end of the retaining frame assembly 14; the tailstock assembly 13 is arranged in the frame of the retaining frame assembly 14; Figure 4 As shown, the tailstock assembly 13 includes a servo linear drive 1301, a second bearing seat 1302 and a top shaft 1303; the second bearing seat 1302 is arranged on the servo linear drive 1301; the top shaft 1303 is arranged in the second bearing seat 1302; the aforementioned servo motor 2, first bearing seat 7, three-jaw chuck 8 and top shaft 1303 are coaxially arranged.

[0022] In the embodiment of the present disclosure, the servo motor 2 is fixed on the servo motor fixing seat 3; the servo electric cylinder 19 is fixed on the servo electric cylinder fixing seat 18, and the tail end of the servo electric cylinder 19 is placed on the electric cylinder pad 20; by setting the fixing seat and the pad, the stability of the servo electric cylinder 19 can be effectively improved.

[0023] In the embodiment of the present disclosure, a tension and pressure sensor 17 is arranged between the external threaded rod end joint bearing 15 and the servo electric cylinder 19; one end of the tension and pressure sensor 17 is connected to the external threaded rod end joint shaft via a connecting fork 16; the other end is connected to the servo electric cylinder 19; linear guide rails 22 are arranged on both sides of the retaining frame assembly 14; guide rail connecting blocks 1404 are arranged on both sides of the aforementioned retaining frame assembly 14; the retaining frame assembly 14 is connected to the linear guide rail 22 via the guide rail connecting block 1404; a linear displacement sensor 21 is arranged on one side of the servo electric cylinder 19; the telescopic end of the servo displacement sensor is connected to the tail end of the aforementioned retaining frame assembly 14.

[0024] In the embodiment of the present disclosure, Figure 2 As shown, the nut fixing assembly 12 includes a nut assembly base 1201, a nut pressing plate 1202, a butterfly nut 1203, a butterfly bolt 1204, and a temperature sensor 1205. The nut 11 assembly is installed in the middle position of the fixing plate 1401 of the retaining frame assembly 14. When installing the nut, rotate the butterfly nut 1203, move the butterfly bolt 1204, remove the nut pressing plate 1202, and install the nut 11 in the slot of the nut assembly base 1201. Press the nut 11 with the nut pressing plate 1202, move the butterfly bolt 1204 to the locking position, and rotate the butterfly nut 1203 to a tightened state. At this time, the nut 11 and the nut fixing assembly 12 become one, and the nut 11 can move linearly along the linear guide rail 22 with the retaining frame assembly 14. As shown Figure 3 As shown, a threaded hole is provided at the bottom of the nut assembly base 1201, and the temperature sensor 1205 is fixed through the threaded hole. The end face of the temperature sensor 1205 can touch the shaft surface of the nut 11, which is used to monitor the temperature change of the nut 11 during the running-in process.

[0025] In the embodiment of the present disclosure, Figure 5 As shown, the retainer assembly 14 comprises a front fixing plate 1401, two side retainers 1402, and a rear end force plate 1403. These four components, fixing plate 1401, retainer 1402, and force plate 1403, are connected end-to-end using screws to form a frame. Guide rail connection blocks 1404 are located on either side of fixing plate 1401. The aforementioned nut fixing assembly 12 is mounted on fixing plate 1401. The externally threaded rod end spherical bearing 15 is mounted on force plate 1403. In this disclosed embodiment, the threaded rod of the externally threaded rod end spherical bearing 15 is coaxial with the lead screw 10.

[0026] In the embodiment of the present disclosure, Figure 1 As shown, a slider 23 is provided on the guide rail of the linear guide rail 22; the aforementioned guide rail connecting block 1404 is fixedly connected to the slider 23; the aforementioned retaining frame assembly 14 is fixed to the upper plane of the slider 23 on both sides through the guide rail connecting block 1404, and can perform linear motion along the linear guide rail 22; this linear motion is parallel to the axis of the screw rod 10 to be ground.

[0027] Two limit switches are provided on the guide rail, one at each end of the guide rail; the first limit switch 24 is provided on the side close to the servo electric cylinder, and the second limit switch 26 is provided on the side close to the servo motor; the front end of the guide rail connecting block 1404 is provided with a switch touch plate 25 for triggering the limit switch; when the nut 11 reaches the limit position on both sides, the switch touch plate 25 will trigger the limit switch, causing the running-in device to be forced to stop.

[0028] In the embodiment disclosed herein, a laser displacement sensor 9 is provided on one side of the aforementioned three-meat chuck 8; the laser beam of the laser displacement sensor 9 is directly irradiated on the shaft of the screw rod 10 to be run-in, and is used to detect the radial runout of the screw rod 10 during clamping, thereby determining whether the screw rod 10 is correctly clamped.

[0029] In the disclosed embodiment, a host computer is also included; the servo motor 2, servo electric cylinder 19, torque sensor 5, laser displacement sensor 9, tension and pressure sensor 17, linear displacement sensor 21, and limit switch are all electrically connected to the host computer. The host computer collects sensor signals and sends control signals to the servo motor 2 and servo electric cylinder 19.

[0030] When running-in the screw, use the three-jaw chuck 8 to clamp one end of the screw 10 to be run-in. A process hole is preset on the other end face of the screw 10. The servo linear drive 1301 in the tailstock assembly 13 drives the second bearing seat 1302 to approach the end face of the other axial end of the screw 10. The top shaft 1303 presses against the hole on the other end face of the screw 10 shaft as a support for the other end face of the screw 10 shaft. At this time, the servo motor 2, the bearing seat, the three-jaw chuck 8, and the top shaft 1303 of the tailstock assembly 13 are coaxial.

[0031] The upper computer controls the rotation of the servo motor 2, which drives the screw 10 to be run-in to rotate. The nut 11 is clamped on the nut fixing assembly 12, the nut fixing assembly 12 is fixed on the retaining frame assembly 14, and the retaining frame assembly 14 is installed on the guide rail slider 23. Driven by the screw 10, the nut 11 moves linearly along the guide rail. The upper computer controls the servo electric cylinder 19 to automatically load onto the retaining frame 1402 according to the set loading value, and the retaining frame 1402 transmits the load force to the nut 11. Feedback is automatically adjusted through the pull-pressure sensor 17, and the stroke is closed-loop controlled to meet the load requirements of the screw 10 assembly running-in. The upper computer monitors the current speed and torque data of the servo motor 2 in real time, and also forms a closed-loop control on the operating speed so that the speed also reaches the required data.

[0032] During this period, the linear displacement sensor 21 measures the running-in stroke of the screw 10 assembly. The laser displacement sensor 9 detects the amount of runout of the screw 10 in real time. The temperature sensor 1205 installed on the base 1201 of the nut assembly monitors the working temperature of the nut 11. When the temperature of the nut 11 exceeds the set value, the equipment temporarily stops running to avoid excessive wear of the nut 11 and changes in mechanical properties, thereby realizing the temperature limit protection function. The torque sensor 5 monitors the running-in torque changes during the running-in work. The tension and pressure sensor 17 detects the axial load force provided by the electric cylinder in real time during the running-in work. The servo driver controls the extension and contraction of the servo electric cylinder 19 in a closed-loop manner based on the monitored axial load force to ensure that the provided axial load force is consistent in real time.

[0033] When the running-in device is running in, various types of test data, including force, speed, displacement and other data, can be displayed in real time on the instrument panel through the host computer external device.

[0034] Example 2 Based on the precision screw assembly running-in device disclosed in the first embodiment, this embodiment discloses a precision screw assembly running-in method, such as Figure 6 As shown, in the embodiment of the present disclosure, the component used for upper-level control adopts a control cabinet, which is provided with a display, an industrial computer, a conditioning box and an instrument box; the conditioning box controls the servo motor 2 and the servo electric cylinder 19 through a driver and a servo controller respectively.

[0035] In the embodiment of the present disclosure, the running-in process includes the following specific processes: Use the three-jaw chuck 8 to clamp one end of the screw rod 10 to be run-in. A process hole is preset on the other end face of the screw rod 10. The servo linear drive 1301 in the tailstock assembly 13 drives the second bearing seat 1302 to approach the end face of the other axial end of the screw rod 10. The top shaft 1303 presses against the hole on the other end face of the screw rod 10 shaft as a support for the other end face of the screw rod 10 shaft. At this time, the servo motor 2, the bearing seat, the three-jaw chuck 8, and the top shaft 1303 of the tailstock assembly 13 are coaxial.

[0036] Set parameters such as load value, load direction, loading time, upper and lower temperature limits of nut 11, and torque judgment value. The industrial computer sends a run-in start command to the conditioning box, which conditions the command and sends it to the servo controller. The servo controller controls the loading of the servo electric cylinder 19. The servo electric cylinder 19 extends and contracts, and the nut 11 is loaded. The conditioning box collects the value of the tension and pressure sensor 17 through the transmitter. When the set load is reached, the conditioning box controls the servo controller to stop loading, at which point the load on the nut 11 reaches the set value.

[0037] The industrial computer sends a rotation command for servo motor 2 to the conditioning box, which conditions the command and sends it to the driver. The driver then drives servo motor 2, marking the beginning of product run-in. During the run-in process, the tension and pressure sensor 17 monitors the axial load force provided by the electric cylinder in real time. If the load exceeds the limit, it sends a command to the servo controller. The servo controller uses the monitored axial load force to control the extension and retraction of the servo electric cylinder 19 in a closed-loop manner, ensuring that the applied axial load force is consistent in real time.

[0038] At the start of the run-in period, the industrial computer records the value detected by torque sensor 5 as the initial run-in torque for screw 10. After the run-in period, the industrial computer records the value detected by torque sensor 5 and automatically determines the run-in result. If the torque value does not reach the set value, the operator repeats the run-in process until the set torque value is reached. The run-in process is deemed qualified and the run-in process is stopped.

[0039] During the running-in process, the temperature sensor 1205 monitors the temperature rise of the nut 11 in real time. When the temperature reaches the set upper limit, the device automatically stops. When the temperature of the nut 11 drops to the lower limit, the device automatically starts the running-in process.

Claims

1. A precision screw assembly running-in device, characterized by: It includes a servo motor, a torque sensor, a first bearing seat, a nut, a tailstock assembly, a cage assembly and a servo electric cylinder; The output end of the servo motor is connected to one end of the torque sensor through a first coupling; the other end of the torque sensor is connected to the input end of the first bearing seat through a second coupling; A three-jaw chuck is installed at the output end of the first bearing seat; The nut is fixedly arranged on the nut fixing assembly; The retainer assembly is in the shape of a frame; the nut fixing assembly is arranged at the front end of the retainer assembly; an external threaded rod end joint bearing is arranged at the rear end of the retainer assembly; The tailstock assembly is disposed in the frame of the retaining frame assembly; the tailstock assembly includes a servo linear drive, a second bearing seat, and a top spindle; the second bearing seat is disposed on the servo linear drive; the top spindle is disposed in the second bearing seat; The servo motor, the first bearing seat, the three-jaw chuck and the top spindle are coaxially arranged; A tension and pressure sensor is provided between the external threaded rod end joint bearing and the servo electric cylinder; one end of the tension and pressure sensor is connected to the external threaded rod end joint shaft via a connecting fork; and the other end is connected to the servo electric cylinder; Both sides of the cage assembly are provided with linear guide rails; both sides of the cage assembly are provided with guide rail connecting blocks; the cage assembly is connected to the linear guide rails via the guide rail connecting blocks; A linear displacement sensor is provided on one side of the servo electric cylinder; the telescopic end of the servo displacement sensor is connected to the tail end of the aforementioned retaining frame assembly.

2. The precision screw assembly running-in device according to claim 1, characterized in that: The nut fixing assembly includes a nut assembly base, a nut pressing plate and a temperature sensor; The base of the nut assembly is provided with a slot for placing the nut; The nut pressing plate is fixedly arranged on the nut assembly base; A threaded hole is provided at the bottom of the base of the nut assembly, and the temperature sensor is fixed through the threaded hole; the end face of the temperature sensor can touch the shaft surface of the nut.

3. The precision screw assembly running-in device according to claim 2, characterized in that: The retainer assembly includes a fixed plate at the front end, retainers on both sides and a force application plate at the rear end; the fixed plate, retainer and force application plate are connected end to end to form a frame; Guide rail connecting blocks are arranged on both sides of the fixing plate; the aforementioned nut fixing assembly is arranged on the fixing plate; and the external threaded rod end joint bearing is arranged on the force application plate.

4. The precision screw assembly running-in device according to claim 3, characterized in that: The guide rail of the linear guide rail is provided with a slider; the guide rail connecting block is fixedly connected to the slider; The guide rail is provided with two limit switches, one at each end of the guide rail; The front end of the guide rail connecting block is provided with a switch touch plate for triggering the limit switch.

5. The precision screw assembly running-in device according to claim 1 or 4, characterized in that: A laser displacement sensor is provided on one side of the aforementioned three-melon chuck.

6. The precision screw assembly running-in device according to claim 5, characterized in that: The servo motor and the servo electric cylinder are fixedly arranged on the servo motor fixing seat and the servo electric cylinder fixing seat respectively.

7. The precision screw assembly running-in device according to claim 6, characterized in that: It also includes a host computer; the aforementioned servo motor, servo electric cylinder, torque sensor, laser displacement sensor, tension and pressure sensor, linear displacement sensor and limit switch are all electrically connected to the aforementioned host computer.

8. A running-in method for the precision screw assembly running-in device according to any one of items 1 to 7 above, characterized in that include: Clamping screw; Clamp one end of the screw to be ground in with a three-jaw chuck; A process hole is pre-machined on the other end face of the screw to be ground; After the screw rod to be ground in passes through the nut, the top shaft presses against the process hole on the other end face of the screw rod shaft; After the screw rod to be run-in is clamped, set the load value, load direction, loading time, screw nut temperature upper limit, screw nut temperature lower limit, and torque judgment value through the host computer; The host computer sends a signal to control the servo electric cylinder to load, and the nut is subjected to the load; the host computer collects the value of the tension and pressure sensor. When the set load is reached, the host computer controls the servo electric cylinder to stop loading. At this time, the load on the nut reaches the set value; The host computer sends a signal to drive the servo motor to work, and the product running-in begins. During the running-in process, the tension and pressure sensor monitors the axial load force provided by the servo electric cylinder in real time. If it exceeds the limit, the host computer will send a command to control the extension and contraction of the servo electric cylinder in a closed loop according to the monitored axial load force; At the beginning of the running-in, the detection value of the torque sensor is recorded as the initial torque of the screw running-in. After the running-in time is reached, the detection value of the torque sensor is recorded and the running-in result is automatically judged. If the torque value does not reach the set value, the running-in process is repeated until the set torque value is reached. The running-in process is judged to be qualified and the running-in process is stopped. During the running-in process, the temperature sensor monitors the temperature rise of the nut in real time. When the set upper limit is reached, the equipment automatically stops. When the temperature of the nut drops to the lower limit, the equipment automatically starts the running-in work.

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