A micro-screw pair transmission efficiency and service life testing device and testing method

Abstract

The application discloses a kind of miniature screw pair transmission efficiency, life test device and test method, belong to screw pair test technical field, comprising: control system, pedestal and sequentially set on pedestal first servo motor, screw pair fixing mechanism, test workbench, loading workbench and second servo motor;Screw pair fixing mechanism is used to install the screw pair to be measured, and one end of screw pair fixing mechanism is connected with first servo motor through main shaft unit, and the other end of screw pair fixing mechanism is connected with one end of test workbench;Test workbench is slid on the linear guide pair of pedestal, and the other end of test workbench is connected with one end of loading workbench through force sensor and force balance lever;Loading workbench is slid on linear guide pair, and the other end of loading workbench is connected with second servo motor through loading screw pair;Control system is used to control first servo motor and second servo motor.Solve the installation of miniature screw pair and the test problem under high speed state.

Description

Technical Field

[0001] This invention belongs to the field of lead screw testing technology, and relates to a device and method for testing the transmission efficiency and life of a miniature lead screw pair. Background Technology

[0002] Most ball screw transmission efficiency testing devices currently on the market are designed for medium to large-sized ball screw assemblies (diameter greater than 20mm, stroke greater than 500mm). The nuts used with these screw assemblies are standard flange-type nuts, and their operating conditions are: the axial load on the screw assembly is less than its rated dynamic load, and the operating speed is generally less than 2000rpm. These testing devices have the following drawbacks:

[0003] (1) It cannot meet the test requirements of miniature ball screw pairs (diameter 4-20mm, length 100-500mm) for high speed (operating speed of more than 4500rpm), large load (bearing axial load greater than the rated dynamic load of the ball screw pair), short stroke (stroke 80-400mm) and high dynamic response.

[0004] (2) The installation and testing of the miniature lead screw and its matching long sleeve-shaped nut were not considered;

[0005] (3) It cannot achieve automatic conversion and programmed design of the test loading load spectrum;

[0006] (4) It is impossible to test the positive and negative transmission efficiency of the micro screw pair at high speed.

[0007] Therefore, it is necessary to provide a device for testing the forward and reverse transmission efficiency and lifespan of a miniature lead screw pair that can meet the testing requirements of high-speed, high-load, short-stroke, high-frequency reciprocating motion. Summary of the Invention

[0008] To address the issue that most existing efficiency testing devices are designed for medium to large-sized ball screw pairs (diameter greater than 20mm, stroke greater than 500mm) and do not consider the installation and testing of miniature ball screws and their matching long sleeve-shaped nuts, this invention provides the following technical solution: a miniature ball screw pair transmission efficiency and life testing device, the testing device comprising: a control system, a base, and a first servo motor, a ball screw pair fixing mechanism, a test worktable, a loading worktable, and a second servo motor sequentially arranged on the base;

[0009] The base has a pair of linear guide rails;

[0010] The lead screw pair fixing mechanism is used to install the lead screw pair to be tested, and the first connecting end of the lead screw pair fixing mechanism is connected to the output end of the first servo motor through the spindle unit, and the second connecting end of the lead screw pair fixing mechanism is connected to the first connecting end of the test workbench.

[0011] The test workbench is slidably located on the linear guide pair. The second connecting end of the test workbench is connected to the first connecting end of the loading workbench through a force-applying balance bar. A force sensor is also provided between the force-applying balance bar and the test workbench.

[0012] The loading table is slidably located on the linear guide pair, and the second connecting end of the loading table is connected to the output end of the second servo motor through the loading screw pair;

[0013] The control system is used to control the first servo motor and the second servo motor.

[0014] Optionally, in the above-mentioned miniature lead screw pair transmission efficiency and life testing device, the diameter of the lead screw in the lead screw pair under test is 4 to 20 mm, the length is 100 to 500 mm, the operating speed of the lead screw reaches more than 4500 rpm, and the stroke is 80 to 400 mm.

[0015] Optionally, in the above-mentioned miniature lead screw pair transmission efficiency and life testing device, the lead screw pair under test includes: the lead screw under test, the lead screw nut under test, the ball bearing, and the reverser installed on the lead screw nut under test.

[0016] The lead screw nut to be tested is a long sleeve-shaped irregular nut, and the lead screw nut to be tested is sleeved on the lead screw to be tested;

[0017] The lead screw to be tested and the lead screw nut to be tested are threaded together, and one end of the lead screw to be tested is connected to the first servo motor through the spindle unit.

[0018] Optionally, in the above-mentioned miniature lead screw pair transmission efficiency and life testing device, the lead screw pair fixing mechanism includes: a connecting plate, a conversion seat, a pressure plate and a connecting seat arranged sequentially along the length direction of the lead screw to be tested;

[0019] The conversion seat is sleeved on the lead screw to be tested, and the conversion seat is connected to the lead screw to be tested;

[0020] The connecting plate is sleeved on the conversion seat, the first connecting end of the connecting plate is connected to the spindle unit, and the second connecting end of the connecting plate is connected to the conversion seat;

[0021] The connecting seat is sleeved on the lead screw nut to be tested. The first connecting end of the connecting seat is connected to the first connecting end of the test workbench, and the second connecting end of the connecting seat is connected to the lead screw nut to be tested through the pressure plate.

[0022] Optionally, in the above-mentioned miniature lead screw pair transmission efficiency and life testing device, the first connecting end of the loading roller lead screw shaft in the loading lead screw pair is connected to the second servo motor through the front support unit of the lead screw, the loading roller nut in the loading lead screw pair is connected to the loading worktable, and the second connecting end of the loading roller lead screw shaft is connected to the base through the rear support unit of the lead screw.

[0023] The number of force-applying balance bars is two, and they are located on both sides of the lead screw rear support unit.

[0024] Optionally, in the above-mentioned micro screw pair transmission efficiency and life testing device, a first temperature sensor is provided between the first servo motor and the spindle unit;

[0025] The test workbench is equipped with a first vibration sensor and a second temperature sensor.

[0026] A third temperature sensor is installed on the periphery of the device to measure the ambient temperature;

[0027] A fourth temperature sensor is provided on the lead screw rear support unit;

[0028] The loading workbench is equipped with a second vibration sensor and a fifth temperature sensor.

[0029] A sixth temperature sensor is installed on the front support unit of the lead screw.

[0030] The first temperature sensor, the second temperature sensor, the third temperature sensor, the fourth temperature sensor, the fifth temperature sensor, the sixth temperature sensor, the first vibration sensor, and the second vibration sensor are all connected to the control system signal.

[0031] Optionally, in the above-mentioned miniature lead screw transmission efficiency and life testing device, the control system includes: a numerical control system, a first servo driver, a second servo driver, and a total loading force processor;

[0032] The total loading force processor is connected to the two force sensors respectively. It is used to summarize the total axial loading force output by the two force sensors in real time when the lead screw pair under test is in positive drive, and to summarize the total driving force input by the two force sensors in real time when the lead screw pair under test is in reverse drive.

[0033] The CNC system is connected to the first servo motor through the first servo driver and is used to control the movement of the first servo motor;

[0034] The first servo driver is used to acquire the real-time torque signal of the first servo motor.

[0035] The CNC system is connected to the second servo motor via the second servo driver and is used to control the movement of the second servo motor.

[0036] This invention also provides the following technical solution: a method for testing the transmission efficiency of a miniature lead screw pair, wherein the transmission efficiency testing method is applicable to the aforementioned miniature lead screw pair transmission efficiency and life testing device, and the transmission efficiency testing method includes the following steps:

[0037] 1) Positive transmission efficiency test

[0038] S1. By setting the master-slave mode through the control system, the first servo motor is in the master drive state, the second servo motor is in the loading state, the test screw pair drives the test worktable to perform reciprocating main motion, and the loading screw pair drives the loading worktable to perform reciprocating loading motion.

[0039] S2. Read the torque signal input to the first servo motor in real time through the first servo driver;

[0040] S3. The total axial loading force signal output by the two force sensors is acquired in real time through the total loading force processor;

[0041] S4. Input the values ​​obtained in S2 and S3 into the computer and calculate the positive transmission efficiency of the lead screw pair to be tested according to the set formula.

[0042] 2) Reverse transmission efficiency test

[0043] S1. By setting the master-slave mode through the control system, the second servo motor is in the active state and the first servo motor is in the driven state. The loading screw pair drives the loading worktable to perform reciprocating main motion, and the screw pair under test drives the test worktable to perform reciprocating loading motion.

[0044] S2. Read the load torque signal output by the first servo motor in real time through the first servo driver;

[0045] S3. The total thrust signal input from the two force sensors is acquired in real time through the total loading force processor;

[0046] S4. Input the values ​​obtained in S2 and S3 into the computer, and calculate the reverse transmission efficiency of the lead screw pair to be tested according to the set formula.

[0047] Optionally, in the above-described method for testing the transmission efficiency of a miniature lead screw pair, in step 1), the computer calculates the positive transmission efficiency of the lead screw pair under test using the following formula:

[0048]

[0049] In the above formula: η is the positive transmission efficiency of the lead screw pair to be measured;

[0050] P2 is the output power of the lead screw pair under test;

[0051] P1 is the input power of the lead screw pair under test;

[0052] V is the speed at which the test workbench is moved by the lead screw nut under test, in m / s;

[0053] ω is the angular velocity of the lead screw to be measured, in rad / s;

[0054] T1 is the total torque input to the first servo motor, in Nm;

[0055] F1 is the total axial loading force output by the two force sensors, in N;

[0056] N is the rotational speed of the lead screw to be measured, in rpm;

[0057] P h The lead of the lead screw pair under test is in mm;

[0058] In step 2), the reverse transmission efficiency of the lead screw pair under test is obtained using the following formula;

[0059]

[0060] In the above formula: η′ is the reverse transmission efficiency of the lead screw pair to be tested;

[0061] P2′ is the output power of the lead screw pair under test;

[0062] P1′ is the input power of the lead screw pair under test;

[0063] ω is the angular velocity of the lead screw to be measured, in rad / s;

[0064] V is the speed at which the test workbench is moved by the lead screw nut under test, in m / s;

[0065] T2 is the load torque output by the first servo motor, in Nm;

[0066] F2 is the total driving force input from the two force sensors, in N;

[0067] N is the rotational speed of the lead screw to be measured, in rpm;

[0068] Ph The lead of the lead screw pair under test is in mm.

[0069] This invention also provides the following technical solution: a method for testing the life of a miniature lead screw pair, the life testing method being applicable to the aforementioned miniature lead screw pair transmission efficiency and life testing device, the life testing method comprising the following steps:

[0070] 1) Preparation and Experiment

[0071] S1. Install the lead screw pair to be tested on the lead screw pair fixing mechanism, and connect the two ends of the lead screw pair fixing mechanism to the first servo motor on the base and the test workbench respectively. Set the test parameters of the lead screw to be tested according to the technical requirements and test objectives.

[0072] S2. Start the lubricating oil pump and water cooler;

[0073] S3. Call the test program in the control system and set the loading force, loading time, loading speed, and number of cycles according to the load spectrum;

[0074] S4. Press the enable key, and after the loading force rises to the specified value, start the test loading and realize the reciprocating motion of the screw pair under test according to the loading requirements of the load spectrum.

[0075] S5. Once the test meets the specified requirements, press the stop button to end the test.

[0076] 2) Monitoring and handling of the experimental process

[0077] S1. During the test, the measurement and monitoring system collects displacement, temperature, vibration and noise data in real time and transmits them to the control system.

[0078] S2. At the specified time intervals or number of runs, stop the machine to check the wear and surface quality of the lead screw pair to be tested;

[0079] S3. Vibration monitoring: Vibration monitoring is carried out during the fatigue life test of the sample. If any abnormality is found, the machine is stopped immediately, and the surface of the lead screw, lead screw nut, and ball bearings to be tested is subjected to peeling detection.

[0080] If fatigue failure is not observed, the bearing and installation accuracy should be checked. After the problem is resolved, the test should be repeated.

[0081] S4. Temperature monitoring: During the fatigue life test of the sample, temperature monitoring shall be carried out, and the temperature of any part of the lead screw pair shall not exceed 50℃.

[0082] If the temperature exceeds 50°C, the test must be stopped, and the seals, lubrication, and installation accuracy of the screw nut under test should be checked for any abnormalities.

[0083] If there are no abnormalities, the axial load of the lead screw to be tested and the sample rotation speed can be adjusted appropriately.

[0084] 3) Analysis of Experimental Results

[0085] Failures caused by inappropriate test loads, insufficient lubrication, or burns and jamming should not be included in the normal failure data.

[0086] The beneficial effects of the technical solution provided by the embodiments of the present invention are as follows:

[0087] This application solves the installation and testing problem of miniature lead screws and their matching long sleeve-shaped special nuts by installing the lead screw pair under test through the lead screw pair fixing mechanism;

[0088] In this application, the master-slave servo electric coupling loading of the lead screw pair under test and the loading lead screw pair is mainly achieved by coordinating two servo motors through the control system to drive the lead screw pair under test and the loading lead screw pair to realize specific loading motion. The operating speed of the lead screw in the lead screw pair under test reaches more than 4500 rpm, which meets the life test requirements of the miniature lead screw pair under high speed, high load and short stroke operating conditions. By setting the master-slave mode through the control system, the test of the forward transmission efficiency and reverse transmission efficiency of the miniature lead screw pair under high speed is realized. Attached Figure Description

[0089] Figure 1 A schematic diagram of a micro-screw pair transmission efficiency and life testing device provided in an embodiment of the present invention;

[0090] Figure 2 (a) and (b) are schematic diagrams of the front and left views of a flange connection type nut in the prior art, respectively.

[0091] Figure 3 This is a partial cross-sectional view of a long sleeve-type irregular nut in the prior art;

[0092] Figure 4 This is a diagram showing the installation effect of the miniature lead screw pair to be tested.

[0093] Figure 5 A flowchart illustrating the loading principle of a miniature lead screw pair using a miniature lead screw pair transmission efficiency and life testing device provided in an embodiment of the present invention.

[0094] Figure 6 A flowchart illustrating the loading principle and efficiency test of a miniature lead screw pair using a miniature lead screw pair transmission efficiency and life testing device provided in an embodiment of the present invention.

[0095] Figure 7 A schematic diagram of segmented loading (according to load spectrum requirements) provided for an embodiment of the present invention;

[0096] In the diagram: 1. First servo motor; 2 and 2', linear guide pair; 3. Spindle unit; 4. Lead screw pair fixing mechanism; 41. Connecting plate; 42. Converter seat; 43. Lead screw to be tested; 44. Pressure plate; 45. Nut of lead screw to be tested; 46. Connecting seat; 5. Test workbench; 6 and 6', force sensor; 7. Rear support unit for lead screw; 8 and 8', force balance bar; 9. Loading lead screw pair; 10. Loading workbench; 11. Front support unit for lead screw; 12. Base; 13. Second servo motor; 14. First temperature sensor; 15. Second temperature sensor; 16. First vibration sensor; 17. Third temperature sensor; 18. Fourth temperature sensor; 19. Fifth temperature sensor; 20. Second vibration sensor; 21. Sixth temperature sensor; 22. Lubricating oil pump; 23. Water chiller; 24. Operating table. Detailed Implementation

[0097] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0098] In the description of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. The terms "connected," "linked," and "set up" used in this invention should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a direct connection or an indirect connection through intermediate components; a wired connection, a radio connection, or a wireless communication signal connection. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0099] Please see Figure 1-6 The present invention provides the following technical solution: a micro screw pair transmission efficiency and life testing device. This testing device includes: a control system, a base 12, and a first servo motor 1, a screw pair fixing mechanism 4, a test worktable 5, a loading worktable 10, and a second servo motor 13 sequentially arranged on the base 12.

[0100] The test object of this application is a miniature lead screw pair (also referred to as the lead screw pair under test or the test lead screw pair), including: the lead screw under test 43, the lead screw nut under test 45 (also referred to as the lead screw nut under test), ball bearings (not shown in the figure), and a reverser (not shown in the figure) mounted on the lead screw nut under test 45. The diameter of the lead screw under test is 4-20 mm, the length is 100-500 mm, and its operating speed reaches over 4500 rpm under the drive of a power device, with a stroke of 80-400 mm. The lead screw nut under test 45 is a long sleeve-type irregular nut (see...). Figure 3 As shown, this refers to an integral part consisting of a long sleeve and a shaped nut, a common structure for lead screw pairs in aerospace and other fields. The length of the "long sleeve" is generally more than three times the diameter of the shaped nut, and sometimes even more than ten times. The function of the long sleeve is to act as a push rod in the drive mechanism of the lead screw pair. The shape of the "shaped nut" differs from the conventional "cylindrical" or "cylindrical with flange" type. The shaped nut generally has two to three radial small cylinders, or one or two cylinders and one or two protruding keys, which generally serve a fixing or guiding function. This structural design method simplifies the design of the servo drive mechanism of the lead screw pair, reduces the weight of the entire mechanism, and is of great significance to the aforementioned fields. The lead screw nut 45 to be tested is sleeved on the lead screw 43 to be tested, and the lead screw 43 to be tested and the lead screw nut 45 to be tested are threaded together.

[0101] Reference Figure 1 As shown, the base 12 has a pair of linear guide rails 2 (and 2'). The lead screw pair fixing mechanism 4 is used to install the lead screw pair to be tested (i.e., the test lead screw pair), solving the installation problem of the miniature lead screw and its matching long sleeve-type irregular nut. Preferably, the lead screw pair fixing mechanism 4 includes: a connecting plate 41, a conversion seat 42, a pressure plate 44, and a connecting seat 46 arranged sequentially along the length direction of the lead screw 43 to be tested; during installation, the conversion seat 42 is sleeved on the lead screw 43 to be tested, and the conversion seat 42 is connected to the lead screw 43 to be tested, which can be detached by means of a locking nut or other connecting parts; the connecting plate 41 is sleeved on the conversion seat 42, and the first connecting end of the connecting plate 41 is connected to the first servo motor 1 through the spindle unit 3, and the first connecting end of the connecting plate 41 is connected to the spindle unit 3 by bolts or other connecting parts. The connection is disassembled. The second connecting end of the connecting plate 41 is connected to the conversion seat 42, which can be detached using bolts or other connecting parts. The connecting seat 46 is fitted onto the lead screw nut 45 to be tested. The first connecting end of the connecting seat 46 is connected to the first connecting end of the test workbench 5, which can be detached using bolts or other connecting parts. The second connecting end of the connecting seat 46 is connected to the lead screw nut 45 to be tested via the pressure plate 44. This solves the installation and testing problem of the miniature lead screw and its matching long sleeve-type shaped nut, and realizes the quick-change installation of the long sleeve-type shaped nut (see installation effect diagram). Figure 4 ).

[0102] The first connecting end (connecting plate 41) of the lead screw pair fixing mechanism 4 is connected to the output end of the first servo motor 1 through the main shaft unit 3. When the first servo motor 1 rotates, it applies a certain torque to the lead screw pair under test (lead screw 43 under test), driving the lead screw 43 under test to rotate. The balls roll between the helical raceway of the lead screw 43 under test and the lead screw nut 45 under test, thereby driving the lead screw nut 45 under test to make linear motion along the axial direction of the lead screw 43 under test, thus realizing the purpose of converting rotational motion into linear motion. The second connecting end (connecting seat 46) of the lead screw pair fixing mechanism 4 is connected to the first connecting end of the test workbench 5. At the same time, the test workbench 5 is located on the linear guide pair 2. Thus, the lead screw pair under test converts the torque from the rotational motion of the lead screw 43 under test into the linear motion of the lead screw nut 45 under test, driving the test workbench 5 to slide along the linear guide pair 2, resulting in axial displacement.

[0103] The second connecting end of the test workbench 5 is rigidly connected to the first connecting end of the loading workbench 10 via a pair of force-applying balance bars 8 (and 8'). These balance bars 8 (and 8'), as rigid connecting rods, do not apply force themselves. Preferably, one end of each balance bar 8 (and 8') is inserted into a mounting hole on the loading workbench 10 and then detachably connected to the loading workbench 10 via a fastening nut. Simultaneously, the loading workbench 10 slides on the linear guide pair 2 (and 2'). Thus, during the test transmission process, the test workbench 5 moves synchronously with the loading workbench 10 via the balance bars 8 (and 8'), and the distance between the test workbench 5 and the loading workbench 10 remains constant. A (tension / compression) force sensor 6 (and 6') is also installed between the balance bars (8 and 8') and the test workbench 5. It should be noted that since the length of the lead screw 43 to be tested varies, if a long lead screw 43 to be tested is required (referred to as long lead screw), the fastening nut needs to be loosened so that the part of the force balance bar 8 (and 8') extending out of the loading workbench 10 can be adaptively extended, and the fastening nut should be tightened again (i.e., the distance between the test workbench 5 and the loading workbench 10 is set according to actual needs), and vice versa.

[0104] The second connection end of the loading table 10 is connected to the output end of the second servo motor 13 via the loading screw pair 9. When the second servo motor 13 is started, it applies a loading force to the loading screw pair 9. This loading force is transmitted sequentially through the loading table 10, the force balance bar 8 (and 8'), and the force sensor 6 (and 6') to the test table 5, and then applied to the screw pair under test, thus achieving loading of the screw pair under test. The loading screw pair 9 is a planetary roller screw pair, composed of a loading roller screw shaft, a loading roller nut, several rollers, and a gear ring, among other components. The loading worktable 10 and the loading roller nut in the loading screw pair 9 are connected by screws. When the second servo motor 13 rotates, it applies a certain torque to the loading screw pair 9 (referring to the loading roller screw shaft) to drive the loading roller screw shaft to rotate. The loading roller screw shaft drives several rollers arranged on the side wall to rotate, thereby causing the loading roller nut to move linearly along the axis of the loading roller screw shaft. This achieves the purpose of converting rotational motion into linear motion. In this way, the loading screw pair 9 converts the torque from the rotational motion of the loading roller screw shaft into the linear motion of the loading roller nut, driving the loading worktable 10 to slide along the linear guide pair 2 (and 2') and undergo axial displacement, while simultaneously moving the test worktable 5 in the same direction.

[0105] Control system (referring to) Figure 1 The numerical control system of the control panel 24 shown in the picture is used to control the first servo motor 1 and the second servo motor 13.

[0106] The output terminals of the second servo motor 13 and the first servo motor 1 face opposite directions. Before testing, the lead screw pair to be tested is first installed on the lead screw pair fixing mechanism 4, and then the connecting plate 41 and the connecting seat 46 in the lead screw pair fixing mechanism 4 are connected to the first servo motor 1 and the test workbench 5 respectively.

[0107] This testing device achieves master-slave servo electric coupling loading function between the lead screw pair under test and the loading lead screw pair 9 through a control system, a servo system (referring to the first servo motor 1 and the second servo motor 13), and their mechanical structure. Specifically, when the first moving shaft formed by the lead screw pair under test is in the master (drive) state, the second moving shaft formed by the loading lead screw pair 9 is in the driven loading state. The two moving shafts automatically generate a certain loading force according to the setting and then reciprocate synchronously. During reversal, the master-slave state of the lead screw pair under test and the loading lead screw pair 9 automatically switches.

[0108] Loading process: According to the loading load spectrum requirements, the first servo motor 1, the lead screw pair under test, the test worktable 5 and its supporting parts form a drive device for main drive; the second servo motor 13, the loading lead screw pair 9, and the loading worktable 10 form a loading device for loading motion. Specifically, when the lead screw pair under test is in positive transmission state, the first servo motor 1 is in main drive state and the second servo motor 13 is in loading state. The first servo motor 1 drives the test worktable 5 to reciprocate main motion through the lead screw pair under test, generating axial displacement. The loading lead screw pair 9 applies a load (also called axial loading force) to the loading worktable 10, driving the loading worktable 10 to perform reciprocating loading motion. When the lead screw pair under test is in reverse transmission state, the second servo motor 13 is in active state and the first servo motor 1 is in driven state (that is, the system adjusts in real time according to the requirements of the loading force and outputs a certain torque to follow the motion). The second servo motor 13 applies a load (also called driving force) to the loading worktable 10 through the loading lead screw pair 9 to drive the loading worktable 10 to perform reciprocating main motion. The lead screw pair under test drives the test worktable 5 to perform reciprocating loading motion.

[0109] This experimental setup consists of a test bench 5, force-applying balance bars 8 (and 8'), force sensors 6 (and 6'), and a loading bench 10, forming a high-rigidity double-bar balance loading mechanism. Both the test bench 5 and the loading bench 10 are made of lightweight, high-strength aerospace-grade aluminum alloy, thus meeting the high dynamic and high-follow-response requirements of the experimental setup. It should be noted that, to meet the motion requirements of the tested (miniature) lead screw pair—that the axial load on the lead screw pair exceeds its rated dynamic load and the operating speed reaches 4500 rpm—the first servo motor 1 and the second servo motor 13 in this application are both high-speed, high-torque, high-power water-cooled servo motors from Siemens.

[0110] It should be noted that in this article, "forward transmission" refers to a transmission method that converts rotary motion into linear motion, while "reverse transmission" refers to a transmission method that converts linear motion into rotary motion. Taking a ball screw as an example, in forward transmission, the screw rotates as the driving element, and the nut moves linearly along the axis of the screw under the action of the balls; in reverse transmission, the nut moves linearly as the driving element, and the screw rotates under the action of the balls.

[0111] This experimental setup utilizes a control system to automatically switch between the forward and reverse transmission processes of the lead screw pair under test, thereby achieving high-speed, high-load, and high-dynamic-response loading. Furthermore, this setup can also test the efficiency of the lead screw pair under test in both forward and reverse transmission. Simply put, in the forward transmission state, force sensors 6 (and 6') are used to measure the axial loading force applied by the loading table 10 to force sensors 6 (and 6'), thus allowing real-time acquisition of the axial loading force signal output by force sensors 6 (and 6'); and in the reverse transmission state, force sensors 6 (and 6') are used to measure the pushing force applied by the loading table 10 to force sensors 6 (and 6'), thus allowing real-time acquisition of the pushing force signal input by force sensors 6 (and 6'). This application uses a CNC system bus to transmit and read the torque value of the first servo motor 1 directly connected to the lead screw pair under test in real time. The acquired values ​​are input into a computer, which calculates the forward and reverse transmission efficiencies according to a pre-set efficiency calculation formula. This embodiment does not limit the specific efficiency calculation formula.

[0112] In this application, the master-slave servo electric coupling loading function of the two lead screw pairs (referring to the lead screw pair under test and the loading lead screw pair 9) is mainly achieved by the control system coordinating two servo motors to drive the two lead screws to realize specific loading movements. The principle is as follows:

[0113] Electrical control coupling: A control system is used to control two servo motors. Master-slave and synchronous modes can be programmed. In master-slave mode, one servo motor is the master motor, moving according to set motion commands, such as rotating at a specific speed and acceleration, driving the nut (worktable) of its connected lead screw pair in linear motion. The other servo motor is the slave motor, its motion adjusted in real time according to the master motor's motion state or external load requirements, either following the master motor's movement or providing corresponding auxiliary motion according to load requirements. The master-slave motion of the first servo motor 1 reflects whether the lead screw pair under test is in forward or reverse transmission. That is, in active mode, if the first servo motor 1 is the master motor, the lead screw pair under test is in forward transmission; if the first servo motor 1 is the slave motor, the lead screw pair under test is in reverse transmission. In synchronous mode, the control system ensures that the two servo motors operate with the same speed, acceleration, and other parameters, causing the nuts (carrying the worktable) of the two lead screw pairs to move synchronously. It should be noted that the forward and reverse transmission efficiency measurements of the miniature lead screw pair are performed in master-slave mode.

[0114] Mechanical structure coupling: The nuts of the two lead screw pairs are connected together via a rigidly connected worktable, force sensors 6 (and 6'), and force-applying balance bars (8 and 8'). When the nut of one lead screw pair (carrying the worktable) moves linearly under the drive of a servo motor, it will drive the nut of the other lead screw pair (carrying the worktable) to move through the connecting structure, thereby realizing the transmission and coupling of force and motion between the two lead screw pairs.

[0115] This testing device can test not only the transmission efficiency of miniature lead screw pairs, but also their (loaded) life. Simply put, when testing the life of a miniature lead screw pair using this device, the lead screw pair under test can operate according to a specified load force, speed, running time, and number of cycles (i.e., a load spectrum), and automatically switch between large and small load spectrum cycles.

[0116] Reference Figure 1 As shown, the first connecting end of the loading roller screw shaft in the loading screw assembly 9 is connected to the second servo motor 13 through the front support unit 11. The loading roller nut in the loading screw assembly 9 is connected to the loading worktable 10 through screws. The second connecting end of the loading roller screw shaft is connected to the base 12 through the rear support unit 7. Preferably, the rear support unit 7 includes a rear bearing housing, a bearing, and a locking nut. The second connecting end (i.e., one end journal) of the loading roller screw shaft is fixed to the bearing housing through the bearing and the locking nut. The rear bearing housing is fixed to the base 12 through screws, thus providing stable support force for the loading screw assembly 9. To improve the balance of the device, there are two force balance bars 8, located on both sides of the rear bearing housing. It should be noted that the number of force sensors 6 is the same as the number of force balance bars 8.

[0117] To control and coordinate the two servo motors to achieve specific loading movements, this device also includes a control system. The control system includes a CNC system (such as a Siemens 828D CNC system), a first servo driver, a second servo driver, and a total loading force processor. For details, refer to... Figure 5 and 6As shown, the total loading force processor is connected to two force sensors 6 (and 6') respectively. It is used to collect the total axial loading force output by the two force sensors 6 (and 6') in real time when the lead screw pair under test is in the forward drive state, and to collect the total driving force input by the two force sensors 6 (and 6') in real time when the lead screw pair under test is in the reverse drive state. The CNC system is connected to the first servo motor 1 through a first servo driver to control the operation of the first servo motor 1. The first servo driver is used to collect the real-time torque signal of the first servo motor 1. For example, when the lead screw pair under test is in the forward drive state, the first servo driver collects the total torque input by the first servo motor 1 in real time; when the lead screw pair under test is in the reverse drive state, the first servo driver collects the loading torque output by the first servo motor 1 in real time. The CNC system is connected to the second servo motor 13 through a second servo driver to control the operation of the second servo motor 13.

[0118] It should be noted that, due to the different requirements of the tested (miniature) lead screw pair for loading load, loading speed, loading time, number of cycles, and cycle mode, the loading load spectrum and automatic switching and programming of the load spectrum of the miniature lead screw pair testing device were specially designed. For example Figure 7 The diagram shown illustrates a segmented loading method used in the (loaded) life test of the lead screw pair under test. This diagram is drawn according to load spectrum requirements and shows two coordinate systems, which we will refer to as the upper and lower coordinate systems for ease of description. In the upper coordinate system, the horizontal axis represents time and the vertical axis represents the (load) load. In the lower coordinate system, the horizontal axis represents time and the vertical axis represents speed (i.e., the rotational speed of the lead screw pair under test). This diagram shows the time the lead screw pair under test operates under a certain load and speed during the (loaded) life test. Specifically, Figure 7 This diagram illustrates the load spectrum for four segments. Within a specified time (a), the tested lead screw pair operates under light load (Q1) and high speed (V1); within a specified time (b), it operates under medium load (Q2) and medium speed (V2); within a specified time (c), it operates under medium load (Q3) and medium speed (V3); and within a specified time (d), it operates under heavy load (Q4) and low speed (V4). It is worth noting that the values ​​of light load (Q1), medium load (Q2), medium load (Q3), and heavy load (Q4) increase sequentially, while the values ​​of high speed (V1), medium speed (V2), medium speed (V3), and low speed (V4) decrease sequentially. (See also...) Figure 7 For the life test of the miniature lead screw pair, the loading force can switch to another state value after a specific running time during the test. This is achieved by writing a program into the CNC system. When designing the loading force control program, a multi-stage loading method is used, with different loading force state values ​​in different stages. The CNC system automatically calculates the number of round trips for each stage based on the total running time, running speed, and lead screw travel distance of each stage.

[0119] It is worth mentioning that when using this testing device to test transmission efficiency, the test can be completed in one reciprocating motion under each load and speed. This is because efficiency testing generally measures the efficiency under a certain load and speed, so one run under one load and speed is sufficient to complete the measurement. However, testing lifespan requires a long reciprocating motion.

[0120] When testing the lifespan of a miniature lead screw pair using this testing device, a first temperature sensor 14 is installed between the first servo motor 1 and the spindle unit 3 to monitor the testing process. A first vibration sensor 16 and a second temperature sensor 15 are installed on the test table 5. During the miniature lead screw pair lifespan test, it is necessary to monitor the temperature rise and vibration of the lead screw under test. Since the temperature rise is relative to the ambient temperature, a third temperature sensor 17 is installed on the periphery of this testing device to measure the ambient temperature. A fourth temperature sensor 18 is installed on the rear support unit 7 of the lead screw. A second vibration sensor 20 and a fifth temperature sensor 19 are installed on the loading table 10. A sixth temperature sensor 21 is installed on the front support unit 11 of the lead screw. The first temperature sensor 14, the second temperature sensor 15, the third temperature sensor 17, the fourth temperature sensor 18, the fifth temperature sensor 19, the sixth temperature sensor 21, the first vibration sensor 16, and the second vibration sensor 20 are all connected to the CNC system signal, and each sensor can transmit the monitored data to the control system (i.e., the signal transmission line). Figure 1 The CNC system on the control panel 24 shown in the image. Several temperature sensors monitor the temperature of different parts of the two lead screw pairs. If the temperature exceeds 50°C, the test must be stopped and an inspection performed. Several vibration sensors monitor the vibration of the two lead screw pairs; if any abnormality is detected, the machine must be stopped immediately.

[0121] Furthermore, this testing device also includes a lubrication and cooling auxiliary system consisting of a lubricating oil pump 22 and a water chiller 23, for the normal operation of the testing device. To better achieve the life test of the miniature lead screw pair, technicians installed a noise sensor (not shown in the figure) at a suitable location on the testing device (such as the base 12) for collecting noise data.

[0122] This invention also provides the following technical solution: a method for testing the transmission efficiency of a miniature lead screw pair. This transmission efficiency testing method is applicable to the aforementioned miniature lead screw pair transmission efficiency and life testing device. The transmission efficiency testing method includes the following steps:

[0123] 1) Positive transmission efficiency test

[0124] S1. By setting the master-slave mode through the control system, the first servo motor 1 is in the master drive state and the second servo motor 13 is in the loading state. The first servo motor 1 drives the test lead screw pair, and then drives the test worktable 5 to perform reciprocating main motion. The second servo motor 13 drives the loading lead screw pair 9, and then drives the loading worktable 10 to perform reciprocating following coupled loading motion.

[0125] It should be noted that when the lead screw pair under test is in positive drive, the first servo motor 1 is the master motor and the second servo motor 13 is the slave motor. Initially, the second servo motor 13 applies a force to the loading lead screw pair 9. At this time, the moving axis system formed by the second servo motor 13, the loading lead screw pair 9, and the loading worktable 10 becomes the loading axis. Since the loading worktable 10 is rigidly connected to the test worktable 5 through two force balance bars 8 (and 8') and two (tension and compression) force sensors 6 (and 6'), the loading axis transmits the loading force to the test worktable 5, thereby loading the lead screw pair under test. However, after reaching a certain force and speed, the second servo motor 13 begins to move synchronously with the first servo motor 1.

[0126] S2. Read the torque signal input to the first servo motor 1 through the first servo driver.

[0127] S3. The total axial loading force signal output by the two force sensors 6 (and 6') is acquired in real time through the total loading force processor.

[0128] S4. Input the values ​​obtained in S2 and S3 into the computer, and calculate the positive transmission efficiency of the lead screw pair to be tested according to the set formula.

[0129] During data processing, the start and stop points of sudden jumps are removed by truncating the beginning and end of the data to obtain the transmission efficiency when the operation is relatively stable.

[0130] Specifically, in step 1), the computer uses the following formula to calculate the positive transmission efficiency of the lead screw pair under test:

[0131]

[0132] In the above formula: η is the positive transmission efficiency of the lead screw pair to be measured;

[0133] P2 is the output power of the lead screw pair under test;

[0134] P1 is the input power of the lead screw pair under test;

[0135] V is the speed at which the test workbench 5 is moved by the lead screw nut 45 under test, and the unit is m / s;

[0136] ω is the angular velocity of the lead screw 43 under test, in rad / s;

[0137] T1 is the total torque input to the first servo motor 1, in Nm;

[0138] F1 is the total axial loading force output by the two force sensors 6 (and 6'), in N;

[0139] N represents the rotational speed of the lead screw 43 under test, in rpm;

[0140] P h The lead of the lead screw pair under test is in mm.

[0141] 2) Reverse transmission efficiency test

[0142] S1. By setting the master-slave mode through the control system, the second servo motor 13 is in the active state and the first servo motor 1 is in the slave state. The second servo motor 13 drives the loading screw pair 9, which in turn drives the loading worktable 10 to perform reciprocating main motion. The first servo motor 1 drives the screw pair under test, which in turn drives the test worktable 5 to perform reciprocating following coupled loading motion.

[0143] It should be noted that when the lead screw pair under test is reverse driven, the second servo motor 13 is the master motor and the first servo motor 1 is the slave motor. Initially, the first servo motor 1 applies a force to the lead screw pair under test. At this time, the moving axis system consisting of the first servo motor 1, the lead screw pair under test, and the test worktable 5 becomes the loading axis, which transmits the loading force to the loading worktable 10, and then loads the loading lead screw pair 9. After reaching a certain force and speed, the first servo motor 1 starts to move synchronously with the second servo motor 13.

[0144] S2. The loading torque signal output by the first servo motor 1 is read through the first servo driver.

[0145] S3. The total thrust signal input from the two force sensors 6 (and 6') is acquired in real time by the total loading force processor.

[0146] S4. Input the values ​​obtained in S2 and S3 into the computer, and calculate the reverse transmission efficiency of the lead screw pair under test according to the set formula. During the data processing, the start and stop jump data points are eliminated by the truncating method to obtain the transmission efficiency when the operation is relatively stable.

[0147] Specifically, in step 2), the computer uses the following formula to calculate the reverse transmission efficiency of the lead screw pair under test;

[0148]

[0149] In the above formula: η′ is the reverse transmission efficiency of the lead screw pair to be tested;

[0150] P2′ is the output power of the lead screw pair under test;

[0151] P1′ is the input power of the lead screw pair under test;

[0152] ω is the angular velocity of the lead screw 43 under test, in rad / s;

[0153] V is the speed at which the test workbench 5 is moved by the lead screw nut 45 under test, and the unit is m / s;

[0154] T2 is the load torque output by the first servo motor 1, in Nm;

[0155] F2 is the total driving force input from the two force sensors 6 (and 6'), in N;

[0156] N is the rotational speed of the lead screw to be measured, in rpm;

[0157] P h The lead of the lead screw pair under test is in mm.

[0158] This invention also provides the following technical solution: a method for testing the life of a lead screw pair, applicable to the aforementioned lead screw pair transmission efficiency and life testing device, the life testing method comprising the following steps:

[0159] 1) Preparation and Experiment

[0160] S1. Install the lead screw pair to be tested on the lead screw pair fixing mechanism 4, and connect the two ends of the lead screw pair fixing mechanism 4 to the first servo motor 1 on the base 12 and the test workbench 5 respectively. Set the test parameters of the lead screw 43 to be tested according to the technical requirements and test objectives.

[0161] S2. Start the lubricating oil pump 22 and the water cooler 23.

[0162] S3. In the control system (referring to the CNC system of console 24), call the test program and set the loading force, loading time, loading speed, and number of cycles according to the load spectrum.

[0163] S4. Press the enable key, and after the loading force rises to the specified value, start the test loading and realize the reciprocating motion of the screw pair under test according to the loading requirements of the load spectrum.

[0164] S5. Once the test meets the specified requirements, press the stop button to end the test.

[0165] 2) Monitoring and handling of the experimental process

[0166] S1. During the test, the measurement and monitoring system collects temperature, vibration and noise data in real time and transmits them to the control system.

[0167] S2. At the specified time intervals or number of runs, stop the machine to check the wear and surface quality of the lead screw pair to be tested.

[0168] The surface microstructure of the balls and raceways can be observed using optical microscopes, electron microscopes, etc.

[0169] S3. Vibration monitoring: Vibration monitoring shall be carried out during the fatigue life test of the sample. If any abnormality is found, the machine shall be stopped immediately, and the surface of the lead screw 43, the lead screw nut 45, and the ball shall be inspected for peeling. If no fatigue failure is found, the bearing and installation accuracy shall be checked. After the problem is resolved, the test shall be repeated.

[0170] S4. Temperature monitoring: During the fatigue life test of the sample, temperature monitoring shall be carried out, and the temperature of any part of the lead screw pair shall not exceed 50℃.

[0171] If the temperature exceeds 50°C, the test must be stopped, and the seals, lubrication, and installation accuracy at both ends of the lead screw nut 45 under test should be checked for any abnormalities.

[0172] If there are no abnormalities, the axial load and sample rotation speed of the lead screw 43 under test can be adjusted appropriately.

[0173] 3) Analysis of Experimental Results

[0174] Failures caused by inappropriate test loads, insufficient lubrication, or burns and jamming should not be included in the normal failure data.

[0175] The evaluation method for the life of miniature lead screw pairs can be based on the specific requirements of customers in special fields or industry standards.

[0176] As is known from common technical knowledge, this invention can be implemented through other embodiments that do not depart from its spirit or essential characteristics. Therefore, the disclosed embodiments described above are merely illustrative in all respects and are not the only ones. All modifications within the scope of this invention or its equivalents are included in this invention.

Claims

1. A device for testing the transmission efficiency and lifespan of a miniature lead screw pair, characterized in that, The testing device includes: a control system, a base, and a first servo motor, a lead screw fixing mechanism, a test worktable, a loading worktable, and a second servo motor sequentially arranged on the base; The base has a pair of linear guide rails; The lead screw pair fixing mechanism is used to install the lead screw pair to be tested, and the first connecting end of the lead screw pair fixing mechanism is connected to the output end of the first servo motor through the spindle unit, and the second connecting end of the lead screw pair fixing mechanism is connected to the first connecting end of the test workbench. The test workbench is slidably located on the linear guide pair. The second connecting end of the test workbench is connected to the first connecting end of the loading workbench through a force-applying balance bar. A force sensor is also provided between the force-applying balance bar and the test workbench. The loading table is slidably located on the linear guide pair, and the second connecting end of the loading table is connected to the output end of the second servo motor through the loading screw pair; The control system is used to control the first servo motor and the second servo motor; The lead screw pair under test includes: a lead screw under test, a lead screw nut under test, ball bearings, and a reverser mounted on the lead screw nut under test. The lead screw nut to be tested is a long sleeve type irregular nut, including: a long sleeve and an irregular nut. The length of the long sleeve is more than 3 times the diameter of the irregular nut. The irregular nut is provided with 2 to 3 radial cylinders or 1 to 2 cylinders and 1 to 2 protruding keys. The lead screw nut to be tested is sleeved on the lead screw to be tested. The lead screw to be tested and the lead screw nut to be tested are threaded together, and one end of the lead screw to be tested is connected to the first servo motor through the spindle unit; The lead screw fixing mechanism includes: a connecting plate, a conversion seat, a pressure plate, and a connecting seat arranged sequentially along the length of the lead screw to be tested; The conversion seat is sleeved on the lead screw to be tested, and the conversion seat is connected to the lead screw to be tested; The connecting plate is sleeved on the conversion seat, the first connecting end of the connecting plate is connected to the spindle unit, and the second connecting end of the connecting plate is connected to the conversion seat; The connecting seat is sleeved on the lead screw nut to be tested. The first connecting end of the connecting seat is connected to the first connecting end of the test workbench, and the second connecting end of the connecting seat is connected to the lead screw nut to be tested through the pressure plate. The number of force-applying balance bars is two, and they are located on both sides of the lead screw rear support unit.

2. The micro screw pair transmission efficiency and life testing device according to claim 1, characterized in that, The diameter of the lead screw in the test lead screw pair is 4-20mm, the length is 100-500mm, the operating speed of the lead screw reaches more than 4500rpm, and the stroke is 80-400mm.

3. The micro screw pair transmission efficiency and life testing device according to claim 1, characterized in that, The first connecting end of the loading roller screw shaft in the loading screw pair is connected to the second servo motor through the front support unit of the screw, the loading roller nut in the loading screw pair is connected to the loading worktable, and the second connecting end of the loading roller screw shaft is connected to the base through the rear support unit of the screw.

4. The micro screw pair transmission efficiency and life testing device according to claim 3, characterized in that, A first temperature sensor is provided between the first servo motor and the spindle unit; The test workbench is equipped with a first vibration sensor and a second temperature sensor. A third temperature sensor is installed on the periphery of the device to measure the ambient temperature; A fourth temperature sensor is provided on the lead screw rear support unit; The loading workbench is equipped with a second vibration sensor and a fifth temperature sensor. A sixth temperature sensor is installed on the front support unit of the lead screw. The first temperature sensor, the second temperature sensor, the third temperature sensor, the fourth temperature sensor, the fifth temperature sensor, the sixth temperature sensor, the first vibration sensor, and the second vibration sensor are all connected to the control system signal.

5. The micro screw drive efficiency and life testing device according to claim 1, characterized in that, The control system includes: a numerical control system, a first servo driver, a second servo driver, and a total loading force processor; The total loading force processor is connected to the two force sensors respectively. It is used to summarize the total axial loading force output by the two force sensors in real time when the lead screw pair under test is in positive drive, and to summarize the total driving force input by the two force sensors in real time when the lead screw pair under test is in reverse drive. The CNC system is connected to the first servo motor through the first servo driver and is used to control the movement of the first servo motor; The first servo driver is used to acquire the real-time torque signal of the first servo motor. The CNC system is connected to the second servo motor via the second servo driver and is used to control the movement of the second servo motor.

6. A method for testing the transmission efficiency of a miniature lead screw pair, characterized in that, The transmission efficiency testing method is applicable to the miniature lead screw pair transmission efficiency and life testing device as described in any one of claims 1-5, and the transmission efficiency testing method includes the following steps: 1) Positive transmission efficiency test S1. By setting the master-slave mode through the control system, the first servo motor is in the master drive state, the second servo motor is in the loading state, the test screw pair drives the test worktable to perform reciprocating main motion, and the loading screw pair drives the loading worktable to perform reciprocating loading motion. S2. Read the torque signal input to the first servo motor in real time through the first servo driver; S3. The total axial loading force signal output by the two force sensors is acquired in real time through the total loading force processor; S4. Input the values ​​obtained in S2 and S3 into the computer and calculate the positive transmission efficiency of the lead screw pair to be tested according to the set formula. 2) Reverse transmission efficiency test S1. By setting the master-slave mode through the control system, the second servo motor is in the active state and the first servo motor is in the driven state. The loading screw pair drives the loading worktable to perform reciprocating main motion, and the screw pair under test drives the test worktable to perform reciprocating loading motion. S2. Read the load torque signal output by the first servo motor in real time through the first servo driver; S3. The total thrust signal input from the two force sensors is acquired in real time through the total loading force processor; S4. Input the values ​​obtained in S2 and S3 into the computer, and calculate the reverse transmission efficiency of the lead screw pair to be tested according to the set formula.

7. The method for testing the transmission efficiency of a miniature lead screw pair according to claim 6, characterized in that, In step 1), the computer uses the following formula to calculate the positive transmission efficiency of the lead screw pair under test: ① In the above formula: η is the positive transmission efficiency of the lead screw pair to be measured; P2 is the output power of the lead screw pair under test; P1 is the input power of the lead screw pair under test; V is the speed at which the test workbench is moved by the lead screw nut under test, in m / s; ω is the angular velocity of the lead screw to be measured, in rad / s; The total torque input to the first servo motor is expressed in Nm. The total axial loading force output by the two force sensors is expressed in N. The rotational speed of the lead screw under test is expressed in rpm. The lead of the lead screw pair under test is in mm; In step 2), the reverse transmission efficiency of the lead screw pair under test is obtained using the following formula; ② In the above formula: η´ is the reverse transmission efficiency of the lead screw pair to be tested; P2´ is the output power of the lead screw pair under test; P1´ is the input power of the lead screw pair under test; ω is the angular velocity of the lead screw to be measured, in rad / s; V is the speed at which the test workbench is moved by the lead screw nut under test, in m / s; The load torque output by the first servo motor is expressed in Nm. The total driving force input from the two force sensors, in N; The rotational speed of the lead screw under test is expressed in rpm. The lead of the lead screw pair under test is in mm.

8. A method for testing the life of a miniature lead screw pair, characterized in that, The life testing method is applicable to the miniature lead screw pair transmission efficiency and life testing device as described in any one of claims 1-5, and the life testing method includes the following steps: 1) Preparation and Experiment S1. Install the lead screw pair to be tested on the lead screw pair fixing mechanism, and connect the two ends of the lead screw pair fixing mechanism to the first servo motor on the base and the test workbench respectively. Set the test parameters of the lead screw to be tested according to the technical requirements and test objectives. S2. Start the lubricating oil pump and water cooler; S3. Call the test program in the control system and set the loading force, loading time, loading speed, and number of cycles according to the load spectrum; S4. Press the enable key, and after the loading force rises to the specified value, start the test loading and realize the reciprocating motion of the screw pair under test according to the loading requirements of the load spectrum. S5. Once the test meets the specified requirements, press the stop button to end the test. 2) Monitoring and handling of the experimental process S1. During the test, the measurement and monitoring system collects displacement, temperature, vibration and noise data in real time and transmits them to the control system. S2. At the specified time intervals or number of runs, stop the machine to check the wear and surface quality of the lead screw pair to be tested; S3. Vibration monitoring: Vibration monitoring is carried out during the fatigue life test of the sample. If any abnormality is found, the machine is stopped immediately, and the surface of the lead screw, lead screw nut, and ball bearings to be tested is subjected to peeling detection. If fatigue failure is not observed, the bearing and installation accuracy should be checked. After the problem is resolved, the test should be repeated. S4. Temperature monitoring: During the fatigue life test of the sample, temperature monitoring shall be carried out, and the temperature of any part of the ball screw pair shall not exceed 50℃. If the temperature exceeds 50°C, the test must be stopped, and the seals, lubrication, and installation accuracy of the screw nut under test should be checked for any abnormalities. If there are no abnormalities, the axial load of the lead screw to be tested and the sample rotation speed can be adjusted appropriately. 3) Analysis of Experimental Results Failures caused by inappropriate test loads, insufficient lubrication, or burns and jamming should not be included in the normal failure data.

Images