Micro lead screw pair transmission efficiency and service life testing device and testing method

Abstract

The invention discloses a device and a method for testing transmission efficiency and service life of a miniature lead screw pair, and belongs to the technical field of lead screw pair testing. The device comprises a control system, a base, and a first servo motor, a lead screw pair fixing mechanism, a test workbench, a loading workbench and a second servo motor which are sequentially arranged on the base; the lead screw pair fixing mechanism is used for installing a to-be-tested lead screw pair, one end of the lead screw pair fixing mechanism is connected with the first servo motor through the main shaft unit, and the other end of the lead screw pair fixing mechanism is connected with one end of the test workbench. The test workbench is slidably located on the linear guide rail pair of the base, and the other end of the test workbench is connected with one end of the loading workbench through a force sensor and a force application balance rod; the loading workbench is slidably located on the linear guide rail pair, and the other end of the loading workbench is connected with the second servo motor through the loading lead screw pair. The control system is used for controlling the first servo motor and the second servo motor. The problems of installation of the miniature lead screw pair and testing in a high-speed state are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of lead screw testing, and relates to a device and a method for testing the transmission efficiency and service life of a micro lead screw pair. Background Art

[0002] At present, most of the lead screw pair transmission efficiency testing devices on the market are designed for medium and large-sized (diameter greater than 20 mm, stroke greater than 500 mm) ball screw pairs. The nut of the tested lead screw pair has a standard flange connection type nut, and its operating conditions are: the axial load borne by the lead screw pair is less than the rated dynamic load of the lead screw pair, and the operating speed is generally less than 2000 rpm. Such testing devices have the following defects:

[0003] (1) It cannot meet the testing requirements of high speed (operating speed up to more than 4500 rpm), large load (axial load borne is greater than the rated dynamic load of the lead screw pair), short stroke (stroke of 80 - 400 mm), and high dynamic response for micro lead screw pairs (diameter 4 - 20 mm, length 100 - 500 mm);

[0004] (2) The installation and testing problems of the micro lead screw and its supporting long sleeve type special-shaped nut are not considered;

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

[0006] (4) It cannot realize the testing of the positive transmission efficiency and reverse transmission efficiency of the micro lead screw pair under high-speed conditions.

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

[0008] In order to at least solve the problem that most of the existing efficiency testing devices are designed for medium and large-sized (diameter greater than 20 mm, stroke greater than 500 mm) ball screw pairs and do not consider the installation and testing of micro lead screws and their supporting long sleeve type special-shaped nuts, the present invention provides the following technical solution: A device for testing the transmission efficiency and service life of a micro lead screw pair, the testing device includes: a control system, a base, a first servo motor, a lead screw pair fixing mechanism, a test workbench, a loading workbench, and a second servo motor that are sequentially arranged on the base;

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

[0010] The lead screw pair fixing mechanism is used to install the lead screw pair to be tested, and the first connection 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 connection end of the lead screw pair fixing mechanism is connected to the first connection end of the test workbench;

[0011] The test workbench slides on the linear guide pair, the second connection end of the test workbench and the first connection end of the loading workbench are connected by a force balancing rod, and a force sensor is also arranged between the force balancing rod and the test workbench;

[0012] The loading workbench slides on the linear guide pair, and the second connection end of the loading workbench is connected to the output end of the second servo motor through a loading lead 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 micro lead screw pair transmission efficiency and life test device, the diameter of the lead screw in the lead screw pair to be tested is 4 - 20 mm, the length is 100 - 500 mm, the running speed of the lead screw reaches more than 4500 rpm, and the stroke is 80 - 400 mm.

[0015] Optionally, in the above-mentioned micro lead screw pair transmission efficiency and life test device, the lead screw pair to be tested includes: a lead screw to be tested, a lead screw nut to be tested, balls, and a reverser installed on the lead screw nut to be tested;

[0016] The lead screw nut to be tested is a long sleeve-shaped special-shaped 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 threadedly connected, 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 micro lead screw pair transmission efficiency and life test device, the lead screw pair fixing mechanism includes: a connection disk, a conversion seat, a pressing plate, and a connection seat arranged in sequence 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 connection disk is sleeved on the conversion seat, the first connection end of the connection disk is connected to the spindle unit, and the second connection end of the connection disk is connected to the conversion seat;

[0021] The connecting seat is sleeved on the screw nut to be measured. 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 screw nut to be measured through the pressing plate.

[0022] Optionally, in the above-mentioned device for testing the transmission efficiency and service life of the micro screw pair, the first connecting end of the loading roller screw shaft in the loading screw pair is connected to the second servo motor through a screw front support unit. The loading roller nut in the loading screw pair is connected to the loading workbench, and the second connecting end of the loading roller screw shaft is connected to the base through a screw rear support unit;

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

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

[0025] A first vibration sensor and a second temperature sensor are arranged on the test workbench;

[0026] A third temperature sensor is arranged on the periphery of the device for measuring the ambient temperature;

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

[0028] A second vibration sensor and a fifth temperature sensor are arranged on the loading workbench;

[0029] A sixth temperature sensor is arranged on the screw front support unit;

[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 signal-connected to the control system.

[0031] Optionally, in the above-mentioned device for testing the transmission efficiency and service life of the micro screw pair, 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 respectively connected to the two force sensors, and is used for, when the screw pair to be measured is in positive transmission, summing up the total axial loading force output by the two force sensors in real time, and for, when the screw pair to be measured is in reverse transmission, summing up the total driving force input by the two force sensors in real time;

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

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

[0035] The numerical control system is connected to the second servo motor through the second servo driver and is used to control the operation of the second servo motor.

[0036] The present invention also provides the following technical solution: a method for testing the transmission efficiency of a micro lead screw pair. The transmission efficiency testing method is applicable to the transmission efficiency and life testing device of the micro lead screw pair as described above. The transmission efficiency testing method includes the following steps:

[0037] 1) Forward transmission efficiency test

[0038] S1. Set the master-slave mode through the control system, make the first servo motor in the main driving state, the second servo motor in the loading state, the lead screw pair to be tested drive the test workbench to make a reciprocating main movement, and the loading lead screw pair drive the loading workbench to make a reciprocating loading movement;

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

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

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

[0042] 2) Reverse transmission efficiency test

[0043] S1. Set the master-slave mode through the control system, make the second servo motor in the active state, the first servo motor in the driven state, the loading lead screw pair drive the loading workbench to make a reciprocating main movement, and the lead screw pair to be tested drive the test workbench to make a reciprocating loading movement;

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

[0045] S3. Obtain the total driving force signal input by the two force sensors in real time through the total loading force processor;

[0046] S4. Input the values obtained in S2 and S3 into a 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-mentioned testing method for the transmission efficiency of the micro lead screw pair, in step 1), the computer calculates the forward transmission efficiency of the lead screw pair to be tested using the following formula:

[0048]

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

[0050] P2 is the output power of the lead screw pair to be tested;

[0051] P1 is the input power of the lead screw pair to be tested;

[0052] V is the speed at which the lead screw nut drives the test workbench to move, with the unit of m / s;

[0053] ω is the angular velocity of the lead screw to be tested, with the unit of rad / s;

[0054] T1 is the total torque input by the first servo motor, with the unit of N.m;

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

[0056] N is the rotational speed of the lead screw to be tested, with the unit of rpm;

[0057] P h is the lead of the lead screw pair to be tested, with the unit of mm;

[0058] In step 2), the reverse transmission efficiency of the lead screw pair to be tested is calculated 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 to be tested;

[0062] P1′ is the input power of the lead screw pair to be tested;

[0063] ω is the angular velocity of the lead screw to be tested, with the unit of rad / s;

[0064] V is the speed at which the lead screw nut drives the test workbench to move, with the unit of m / s;

[0065] T2 is the loading torque output by the first servo motor, with the unit of N.m;

[0066] F2 is the total driving force input by the two force sensors, with the unit of N;

[0067] N is the rotational speed of the lead screw to be tested, with the unit of rpm;

[0068] Ph It is the lead of the lead screw pair to be measured, with the unit of mm.

[0069] The present invention also provides the following technical solution: a method for testing the life of a micro lead screw pair. The life test method is applicable to the transmission efficiency and life test device of the micro lead screw pair as described above. The life test method includes the following steps:

[0070] 1) Preparation and test

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

[0072] S2. Start the lubricating oil pump and the 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. After the loading force rises to the specified value, start the test loading, and realize the reciprocating motion of the lead screw pair to be measured according to the loading requirements of the load spectrum.

[0075] S5. When the test reaches the specified requirements, press the stop key to end the test.

[0076] 2) Monitoring and processing during the test

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

[0078] S2. Stop the machine at regular time intervals or number of runs to check the wear condition and surface quality of the lead screw pair to be measured.

[0079] S3. Vibration monitoring: During the fatigue life test of the sample, conduct vibration monitoring. If any abnormality is found, immediately stop the machine, and conduct spalling detection on the surface of the lead screw to be measured, the lead screw nut to be measured, and the balls.

[0080] If no fatigue failure occurs, check the bearings and installation accuracy. After the problems are eliminated, restart the test.

[0081] S4. Temperature monitoring: During the fatigue life test of the sample, conduct temperature monitoring. The temperature of any part of the lead screw pair cannot exceed 50 °C.

[0082] If it exceeds 50 °C, the test needs to be aborted, and check whether there are any abnormalities in the seals at both ends of the lead screw nut to be measured, lubrication, and installation accuracy.

[0083] When there is no abnormality, the axial load and sample rotation speed of the lead screw to be measured can be appropriately adjusted;

[0084] 3) Analysis of test results

[0085] For the failed products caused by inappropriate test loads, lack of lubrication, and seizure due to burning, they shall not be included in the normal failure data.

[0086] The beneficial effects brought by the technical solution provided by the embodiment of the present invention are:

[0087] In this application, the lead screw pair to be measured is installed through the lead screw pair fixing mechanism, which solves the installation and testing problems of the micro lead screw and its supporting long sleeve-shaped special-shaped nut;

[0088] In this application, the master-slave servo electric coupling loading of the lead screw pair to be measured and the loading lead screw pair mainly coordinates the two servo motors to drive the lead screw pair to be measured and the loading lead screw pair through the control system to achieve a specific loading motion. The running speed of the lead screw in the lead screw pair to be measured reaches more than 4500 rpm, meeting the life test requirements of the micro lead screw pair under the conditions of high speed, large load, and short stroke operation. And by setting the master-slave mode through the control system, the testing of the positive transmission efficiency and reverse transmission efficiency of the micro lead screw pair in the high-speed state is realized. Brief description of the drawings

[0089] Figure 1 It is a schematic structural diagram of a device for testing the transmission efficiency and life of a micro lead screw pair provided by an embodiment of the present invention;

[0090] Figure 2 Among them, (a) and (b) are respectively the front view and left view structural schematic diagrams of the flange connection type nut in the prior art;

[0091] Figure 3 It is a partial sectional view structural schematic diagram of the long sleeve-shaped special-shaped nut in the prior art;

[0092] Figure 4 It is the installation effect diagram of the micro lead screw pair to be measured;

[0093] Figure 5 It is a flow chart of the loading principle of the micro lead screw pair using a device for testing the transmission efficiency and life of a micro lead screw pair provided by an embodiment of the present invention;

[0094] Figure 6 It is a flow chart of the loading principle and efficiency test of the micro lead screw pair using a device for testing the transmission efficiency and life of a micro lead screw pair provided by an embodiment of the present invention;

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

[0096] In the figure: 1. First servo motor; 2 and 2'. Linear guide pair; 3. Spindle unit; 4. Screw pair fixing mechanism; 41. Connecting plate; 42. Conversion seat; 43. Screw to be measured; 44. Pressure plate; 45. Screw nut to be measured; 46. Connecting seat; 5. Test workbench; 6 and 6'. Force sensors; 7. Rear support unit of screw; 8 and 8'. Force balance lever; 9. Loading screw pair; 10. Loading workbench; 11. Front support unit of 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 console. Detailed implementation mode

[0097] To make the objectives, technical solutions and advantages of the present invention clearer, the following will further describe the implementation modes of the present invention in detail with reference to the accompanying drawings.

[0098] In the description of the present invention, the orientation or positional relationships indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", etc. are based on the orientation or positional relationships shown in the drawings. It is only for the convenience of describing the present invention and does not require the present invention to be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of the present invention. The terms "connected", "connected to", and "arranged" used in the present invention should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection; it can be directly connected or indirectly connected through an intermediate component; it can be a wired electrical connection, a radio connection, or a wireless communication signal connection. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0099] Please refer to Figures 1-6 , the present invention provides the following technical solution: A device for testing the transmission efficiency and service life of a micro screw pair. This testing device includes: a control system, a base 12, a first servo motor 1, a screw pair fixing mechanism 4, a test workbench 5, a loading workbench 10, and a second servo motor 13 that are sequentially arranged on the base 12.

[0100] The test object of this application is a micro lead screw pair (also known as the lead screw pair to be tested or the test lead screw pair), including: the lead screw 43 to be tested, the lead screw nut 45 to be tested (also known as the lead screw nut to be tested), balls (not shown in the figure), and a reverser (not shown in the figure) installed on the lead screw nut 45 to be tested. The diameter of the lead screw to be tested is 4 - 20 mm, the length is 100 - 500 mm, and driven by a power device, its operating speed reaches over 4500 rpm, and the stroke is 80 - 400 mm. The lead screw nut 45 to be tested is a long sleeve-shaped special-shaped nut (see Figure 3 shown, referring to an integral part composed of a long sleeve and a special-shaped nut, which is a common structure for lead screw pair nuts in fields such as aerospace. The length of the "long sleeve" is generally more than 3 times the diameter of the special-shaped nut, and in some cases, even more than 10 times. The function of the long sleeve is to act as a push rod in the drive mechanism using the lead screw pair. The shape of the "special-shaped nut" is different from the conventional "cylindrical" or "cylindrical plus flange type". Generally, two to three radial small cylinders are arranged on the special-shaped nut, or one or two cylinders and one or two convex keys are arranged. These small cylinders and convex keys generally play a role in fixing or guiding. This structural design method simplifies the design of the servo drive mechanism of the lead screw pair, can reduce the weight of the entire mechanism, and is of great significance to the above 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 threadedly connected.

[0101] Referring to Figure 1 shown, the base 12 has a pair of linear guide pairs 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 micro lead screw and its supporting long sleeve-shaped special-shaped nut. Preferably, the lead screw pair fixing mechanism 4 includes: a connection disk 41, a conversion seat 42, a pressing plate 44, and a connection seat 46 arranged in sequence 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, such as detachably connected through connecting parts such as lock nuts; the connection disk 41 is sleeved on the conversion seat 42, the first connection end of the connection disk 41 is connected to the first servo motor 1 through the main shaft unit 3, and the first connection end of the connection disk 41 and the main shaft unit 3 are detachably connected through connecting parts such as bolts, and the second connection end of the connection disk 41 is connected to the conversion seat 42, such as detachably connected through connecting parts such as bolts; the connection seat 46 is sleeved on the lead screw nut 45 to be tested, the first connection end of the connection seat 46 is connected to the first connection end of the test workbench 5, such as detachably connected through connecting parts such as bolts; the second connection end of the connection seat 46 is connected to the lead screw nut 45 to be tested through the pressing plate 44, solving the installation and testing problem of the micro lead screw and its supporting long sleeve-shaped special-shaped nut, and realizing the quick-change installation of the long sleeve-shaped special-shaped nut (see the installation effect diagram in Figure 4 ).

[0102] The first connection end of the lead screw pair fixing mechanism 4 (referring to the connection disk 41) is connected to the output end of the first servo motor 1 through the spindle unit 3. In this way, when the first servo motor 1 rotates, a certain torque is applied to the lead screw pair to be measured (referring to the lead screw 43 to be measured), driving the lead screw 43 to be measured to rotate. The balls roll between the spiral raceways of the lead screw 43 to be measured and the lead screw nut 45 to be measured, thereby driving the lead screw nut 45 to move linearly along the axis direction of the lead screw 43 to be measured, achieving the purpose of converting rotational motion into linear motion. The second connection end of the lead screw pair fixing mechanism 4 (referring to the connection seat 46) is connected to the first connection end of the test workbench 5. At the same time, the test workbench 5 is located on the linear guide pair 2. In this way, the lead screw pair to be measured converts the torque from the rotational motion of the lead screw 43 to be measured into the linear motion of the lead screw nut 45 to be measured, driving the test workbench 5 to slide along the linear guide pair 2 and generating an axial displacement.

[0103] The second connection end of the test workbench 5 and the first connection end of the loading workbench 10 are rigidly connected through a pair of force balancing rods 8 (and 8'). The force balancing rods 8 (and 8'), as rigid connecting rods, do not have the function of applying force by themselves. Preferably, one end of the force balancing rod 8 (and 8') passes through the mounting hole on the loading workbench 10 and is detachably connected to the loading workbench 10 through a fastening nut. At the same time, the loading workbench 10 slides on the linear guide pairs 2 (and 2'). In this way, during the process of testing the transmission, the test workbench 5 drives the loading workbench 10 to move synchronously through the force balancing rods 8 (and 8'), and the distance between the test workbench 5 and the loading workbench 10 remains unchanged. (Tensile / compressive) force sensors 6 (and 6') are also provided between the force balancing rods (8 and 8') and the test workbench 5. It should be noted that since the lengths of the lead screws 43 to be measured are different, if the long lead screw 43 to be measured (abbreviated as the long screw) needs to be tested, the fastening nut needs to be loosened to adaptively extend the part of the force balancing rod 8 (and 8') extending out of the loading workbench 10, and then the fastening nut is tightened again (that is, set the distance between the test workbench 5 and the loading workbench 10 according to actual needs), and vice versa.

[0104] The second connection end of the loading workbench 10 is connected to the output end of the second servo motor 13 through the loading lead screw pair 9. After starting the second servo motor 13, the second servo motor 13 applies a loading force to the loading lead screw pair 9. This loading force is transmitted to the test workbench 5 through the loading workbench 10, the force - adding balance bars 8 (and 8') and the force sensors 6 (and 6'), and is applied to the lead screw pair to be tested through the test workbench 5, thus realizing the loading of the lead screw pair to be tested. The loading lead screw pair 9 adopts a planetary roller screw pair, which consists of a loading roller screw shaft, a loading roller nut, several rollers, a ring gear and other components. The loading workbench 10 is connected to the loading roller nut in the loading lead screw pair 9 by screws. When the second servo motor 13 rotates, a certain torque is applied to the loading lead 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, thus driving the loading roller nut to move linearly along the axis of the loading roller screw shaft, achieving the purpose of converting rotational motion into linear motion. In this way, the loading lead 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 to drive the loading workbench 10 to slide along the linear guide pair 2 (and 2'), generating an axial displacement and driving the test workbench 5 to move in the same direction at the same time.

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

[0106] The output ends of the second servo motor 13 and the first servo motor 1 face in opposite directions. Before the test, first install the lead screw pair to be tested on the lead screw pair fixing mechanism 4, and then connect the connection plate 41 and the connection seat 46 in the lead screw pair fixing mechanism 4 to the first servo motor 1 and the test workbench 5 respectively.

[0107] This test device realizes the master - slave servo electric coupling loading function of the lead screw pair to be tested and the loading lead screw pair 9 through the control system, the servo system (referring to the first servo motor 1 and the second servo motor 13) and its mechanical structure. Specifically, when the first moving axis formed by the lead screw pair to be tested is in the main (driving) state, the second moving axis formed by the loading lead screw pair 9 is in the slave loading state. After automatically generating a certain loading force according to the setting, the two moving axes perform synchronous reciprocating motion. When reversing, the master - slave states of the lead screw pair to be tested and the loading lead screw pair 9 are automatically switched.

[0108] Loading process: According to the requirements of the loading load spectrum, the first servo motor 1, the lead screw pair to be tested, the test workbench 5 and its supporting parts form a driving device for main driving; the second servo motor 13, the loading lead screw pair 9, and the loading workbench 10 form a loading device for loading movement. Specifically, in the forward transmission state of the lead screw pair to be tested, the first servo motor 1 is in the main driving state, and the second servo motor 13 is in the loading state. The first servo motor 1 drives the test workbench 5 to reciprocate in the main movement to generate an axial displacement through the lead screw pair to be tested. The loading lead screw pair 9 applies a load (also called axial loading force) to the loading workbench 10 to drive the loading workbench 10 to reciprocate in the loading movement. In the reverse transmission state of the lead screw pair to be tested, the second servo motor 13 is in the active state, and the first servo motor 1 is in the driven state (i.e., adjusted in real time by the system according to the magnitude of the loading force, and outputs a certain torque to perform a following movement). The second servo motor 13 applies a load (also called driving force) to the loading workbench 10 through the loading lead screw pair 9 to drive the loading workbench 10 to reciprocate in the main movement, and the lead screw pair to be tested drives the test workbench 5 to perform reciprocating loading movement.

[0109] This test device consists of the test workbench 5, the force application balance rods 8 (and 8'), the force sensors 6 (and 6'), the loading workbench 10, etc. to jointly form a high-rigidity double-rod balance loading mechanism; and both the test workbench 5 and the loading workbench 10 are made of lightweight and high-strength aviation aluminum alloy, so it can meet the requirements of high dynamics and high followability of the test device. It should be noted that in order to meet the movement condition requirements of the lead screw pair to be tested (micro): the axial load borne by the lead screw pair is greater than the rated dynamic load of the lead screw pair, and the running speed reaches 4500 rpm. Both the first servo motor 1 and the second servo motor 13 of this application are selected as Siemens high-speed, large-torque, high-power servo motors with water cooling.

[0110] It should be noted that the forward transmission in this article refers to the transmission method of converting rotary motion into linear motion. The reverse transmission refers to the transmission method of converting linear motion into rotary motion. Taking the ball screw as an example, in the forward transmission, the screw acts as the driving part to rotate, and under the action of the balls, the nut moves linearly along the axis of the screw; in the reverse transmission, the nut acts as the driving part to move linearly, and drives the screw to rotate under the action of the balls.

[0111] This test device uses a control system to automatically switch between the forward and reverse transmission processes of the lead screw pair to be tested, thereby achieving high-speed, high-load, and high-dynamic-response loading of the test device. In addition, the forward and reverse transmission efficiencies of the lead screw pair to be tested can also be measured through this device. Simply put, when the lead screw pair to be tested is in the forward transmission state, a force sensor 6 (and 6') is used to measure the axial loading force applied by the loading workbench 10 to the force sensor 6 (and 6'), so that the axial loading force signal output by the force sensor 6 (and 6') can be collected in real time; and when the lead screw pair to be tested is in the reverse transmission state, a force sensor 6 (and 6') is used to measure the driving force applied by the loading workbench 10 to the force sensor 6 (and 6'), so that the driving force signal input by the force sensor 6 (and 6') can be collected in real time. In this application, through the numerical control system bus transmission, the torque value of the first servo motor 1 directly connected to the lead screw pair to be measured is read in real time. The obtained values are input into a computer, and the computer can respectively calculate the forward transmission efficiency and the reverse transmission efficiency according to the pre-set efficiency calculation formula. The specific efficiency calculation formula is not limited in this embodiment.

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

[0113] Electrical control coupling: The control system is used to control the two servo motors. The master-slave mode and the synchronous mode can be set through programming. In the master-slave mode, one servo motor is the master motor and moves according to the set motion instructions, such as rotating at a specific speed and acceleration, driving the nut (workbench) of the lead screw pair it is connected to to perform a linear motion; the other servo motor is the slave motor, and its motion is adjusted in real time according to the motion state of the master motor or the external loading requirements, realizing following the motion of the master motor or providing corresponding auxiliary motion according to the loading requirements. The master-slave motion of the first servo motor 1 exactly reflects whether the lead screw pair to be tested is in the forward or reverse transmission state. That is, in the active mode, if the first servo motor is the master motor, the lead screw pair to be tested is in the forward transmission state; if the first servo motor 1 is the slave motor, the lead screw pair to be tested is in the reverse transmission state. In the synchronous mode, the control system ensures that the two servo motors operate with the same parameters such as speed and acceleration, so that the nuts (carrying the workbench) of the two lead screw pairs move synchronously. It should be noted that the measurement of the forward and reverse transmission efficiencies of the micro lead screw pair is carried out in the master-slave mode.

[0114] Mechanical structure coupling: The nuts of two lead screw pairs are connected together through a rigidly connected workbench, force sensors 6 (and 6') and force balancing rods (8 and 8'). When the nut of one lead screw pair (with the workbench) generates a linear motion driven by a servo motor, it will drive the nut of the other lead screw pair (with the workbench) to move through the connection structure, thus realizing the transmission and coupling of force and motion between the two lead screw pairs.

[0115] This test device can not only test the transmission efficiency of the micro lead screw pair, but also test the (loaded) life of the micro lead screw pair. Simply put, when using this test device to test the life of the micro lead screw pair, the lead screw pair to be tested can operate according to the specified loading force, speed, running time, number of cycles, that is, the load spectrum, and realize the automatic switching of the large and small cycles of the load spectrum.

[0116] Refer to Figure 1 As shown, the first connection end of the loading roller screw shaft in the loading lead screw pair 9 is connected to the second servo motor 13 through the lead screw front support unit 11. The loading roller nut in the loading lead screw pair 9 is connected to the loading workbench 10 by screws. The second connection end of the loading roller screw shaft is connected to the base 12 through the lead screw rear support unit 7. Preferably, the lead screw rear support unit 7 includes a rear bearing seat, a bearing and a locking nut. The second connection end (i.e., one end journal) of the loading roller screw shaft is fixed to the bearing seat through the bearing and the locking nut, and the rear bearing seat is fixed to the base 12 by screws, so as to provide a stable supporting force for the loading lead screw pair 9. In order to improve the balance of the device, the number of force balancing rods 8 is two, and they are located on both sides of the rear bearing seat. It should be noted that the number of force sensors 6 is the same as the number of force balancing rods 8.

[0117] In order to control and coordinate the two servo motors to achieve a specific loading motion, this device also includes: a control system. The control system includes: a numerical control system (such as the Siemens 828D numerical control system), a first servo driver, a second servo driver, and a total loading force processor. Specifically, refer to Figure 5 and 6As shown in the figure, the total load force processor is respectively connected to two force sensors 6 (and 6'), and is used to sum up the total axial load force output by the two force sensors 6 (and 6') in real time when the lead screw pair to be tested is in the forward transmission state, and is used to sum up the total driving force input by the two force sensors 6 (and 6') in real time when the lead screw pair to be tested is in the reverse transmission state. The numerical control system is connected to the first servo motor 1 through the first servo driver, and is used 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 to be tested is in the forward transmission state, the first servo driver collects the total torque input by the first servo motor 1 in real time. When the lead screw pair to be tested is in the reverse transmission state, the first servo driver collects the load torque output by the first servo motor 1 in real time. The numerical control system is connected to the second servo motor 13 through the second servo driver, and is used to control the operation of the second servo motor 13.

[0118] It should be noted that due to the different requirements of the lead screw pair to be tested (micro lead screw pair) for the loading load, loading speed, loading time, number of cycles, and cycling mode, the loading load spectrum, automatic switching of the load spectrum, and programming of the micro lead screw pair test device are specially designed. For example Figure 7 As shown in the figure, it is a schematic diagram of a segmented loading method used for the (loading) life test of the lead screw pair to be tested. This schematic diagram is drawn according to the requirements of the load spectrum. Two coordinate systems are shown in the figure. For the convenience of description, we will call them the upper coordinate system and the lower coordinate system respectively. Among them, the abscissa of the upper coordinate system represents time, and the ordinate represents (load) load. The abscissa of the lower coordinate system represents time, and the ordinate represents speed (that is, the rotation speed of the lead screw pair to be tested). This figure shows that during the (loading) life test, the lead screw pair to be tested runs for a certain time under a certain load and a certain speed. Specifically, Figure 7 It is a schematic diagram of a four-segment loading load spectrum. Among them, within the specified time (a), the lead screw pair to be tested runs at a light load Q1 and a high speed V1; within the specified time (b), the lead screw pair to be tested runs at a medium load Q2 and a medium speed V2; within the specified time (c), the lead screw pair to be tested runs at a medium load Q3 and a medium speed V3; within the specified time (d), the lead screw pair to be tested runs at a heavy load Q4 and a low speed V4. It is worth mentioning that the magnitudes of the light load Q1, medium load Q2, medium load Q3, and heavy load Q4 increase in sequence, while the magnitudes of the high speed V1, medium speed V2, medium speed V3, and low speed V4 decrease in sequence. See Figure 7 , for the loading of the micro lead screw pair life test, that is: during the test process, the loading force can be switched to another state value after running for a specific time, which is realized by writing the built-in program of the numerical control system. When designing the loading force control program, it is divided into a multi-stage loading method, and the state values of the loading force in different stages are different. The numerical control system automatically calculates the number of running round trips in each stage according to the total running time, running speed, and lead screw running stroke in each stage.

[0119] It is worth mentioning that when using this test device to test the transmission efficiency, the test can be completed with one reciprocating motion under each load and each speed. This is because the efficiency test generally measures the efficiency under a certain load and a certain speed, so the measurement can be completed with one run under a load and a speed, while a long-term reciprocating motion is required to test the life.

[0120] When the life of a micro screw pair is tested using the test device, a first temperature sensor 14 is provided between the first servo motor 1 and the spindle unit 3 in order to monitor the test process. A first vibration sensor 16 and a second temperature sensor 15 are provided on the test bench 5. When testing the life of a micro screw pair, it is necessary to monitor the temperature rise and vibration of the screw being (to be) tested, and the temperature rise is relative to the ambient temperature, so the present application provides a third temperature sensor 17 on the periphery of the test device for measuring the ambient temperature. A fourth temperature sensor 18 is provided on the screw rear support unit 7. A second vibration sensor 20 and a fifth temperature sensor 19 are provided on the loading bench 10. A sixth temperature sensor 21 is provided on the screw front support unit 11. 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 several sensors can transmit the monitored data to the control system (referring to Figure 1 The numerical control system of the operating table 24 in the picture shown). The temperature sensors are used to monitor the temperature of different parts of the two screw pairs. Once the temperature exceeds 50°C, the test needs to be stopped and checked. Several vibration sensors are used to monitor the vibration of the two screw pairs. If an abnormality is found, the machine will be stopped immediately.

[0121] Furthermore, the test device also includes: a lubrication and cooling auxiliary system composed of a lubricating oil pump 22 and a water cooler 23, which is used to ensure the normal operation of the test device. In order to better implement the life test of the micro screw pair, the technicians installed a noise sensor (not shown in the figure) for collecting noise data at a suitable position of the test device (such as the base 12).

[0122] The present invention also provides the following technical solution: a method for testing the transmission efficiency of a micro screw pair. The transmission efficiency testing method is applicable to the above-mentioned micro screw pair transmission efficiency and life testing device. The transmission efficiency testing method comprises the following steps:

[0123] 1) Positive transmission efficiency test

[0124] S1. Set the master-slave mode through the control system. When the first servo motor 1 is in the main driving state and the second servo motor 13 is in the loading state, the first servo motor 1 drives the lead screw pair to be measured, and then drives the test workbench 5 to perform a reciprocating main movement. The second servo motor 13 drives the loading lead screw pair 9 and then drives the loading workbench 10 to perform a reciprocating following coupling loading movement.

[0125] It should be noted that when the lead screw pair to be measured is in positive transmission, the first servo motor 1 is the main 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 composed of the second servo motor 13, the loading lead screw pair 9, and the loading workbench 10 becomes the loading axis. Since the loading workbench 10 is rigidly connected to the test workbench 5 through two force-balancing rods 8 (and 8') and two (tensile-compressive) force sensors 6 (and 6'), the loading axis transmits the loading force to the test workbench 5, and then loads the lead screw pair to be measured. However, after reaching a certain force and speed, the second servo motor 13 starts to move synchronously with the first servo motor 1.

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

[0127] S3. Obtain the total axial loading force signals output by the two force sensors 6 (and 6') 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 measured according to the set formula.

[0129] During the data processing, the sudden jump data points at both the start and stop ends are discarded by the method of truncating the head and tail to obtain the transmission efficiency when the operation is relatively stable.

[0130] Specifically, in step 1), the computer uses the following formula to obtain the positive transmission efficiency of the lead screw pair to be measured:

[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 to be measured;

[0134] P1 is the input power of the lead screw pair to be measured;

[0135] V is the speed at which the lead screw nut 45 drives the test workbench 5 to move, with the unit of m / s;

[0136] ω is the angular velocity at which the lead screw 43 rotates, with the unit of rad / s;

[0137] T1 is the total torque input by the first servo motor 1, with the unit of N.m;

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

[0139] N is the rotational speed of the lead screw 43 to be measured, with the unit of rpm;

[0140] P h is the lead of the lead screw pair to be measured, with the unit of mm.

[0141] 2) Reverse transmission efficiency test

[0142] S1. Set the master-slave mode through the control system, make the second servo motor 13 in the active state, the first servo motor 1 in the slave state, the second servo motor 13 drives the loading lead screw pair 9, and then drives the loading workbench 10 to make a reciprocating main movement, and the first servo motor 1 drives the lead screw pair to be measured, and then drives the test workbench 5 to make a reciprocating following coupled loading movement.

[0143] It should be noted that when the lead screw pair to be measured is reversely transmitted, the second servo motor 13 is the main 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 to be measured. At this time, the moving axis system composed of the first servo motor 1, the lead screw pair to be measured, and the test workbench 5 becomes the loading axis to transmit the loading force to the loading workbench 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. Read the loading torque signal output by the first servo motor 1 through the first servo driver.

[0145] S3. Obtain the total driving force signal input by the two force sensors 6 (and 6') in real time through 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 to be measured according to the set formula. During the data processing, the sudden jump data points at both ends of the start and stop are removed by the truncation method to obtain the transmission efficiency when the operation is relatively stable.

[0147] Specifically, in step 2), the computer uses the following formula to obtain the reverse transmission efficiency of the lead screw pair to be measured;

[0148]

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

[0150] P2′ is the output power of the lead screw pair to be measured;

[0151] P1′ is the input power of the lead screw pair to be measured;

[0152] ω is the angular velocity of the rotation of the lead screw 43 to be measured, with the unit of rad / s;

[0153] V is the speed at which the lead screw nut 45 to be measured drives the test workbench 5 to move, with the unit of m / s;

[0154] T2 is the loading torque output by the first servo motor 1, with the unit of N·m;

[0155] F2 is the total driving force input by the two force sensors 6 (and 6'), with the unit of N;

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

[0157] P h is the lead of the lead screw pair to be measured, with the unit of mm.

[0158] The present invention also provides the following technical solution: A method for testing the life of a lead screw pair. The life test method is applicable to the lead screw pair transmission efficiency and life test device as above. The life test method includes the following steps:

[0159] 1) Preparation and test

[0160] S1. Install the lead screw pair to be measured 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 measured according to the technical requirements and test purposes.

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

[0162] S3. In the control system (referring to the numerical control system of the 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. After the loading force rises to the specified value, start the test loading, and realize the reciprocating motion of the lead screw pair to be measured according to the loading requirements of the load spectrum.

[0164] S5. When the test reaches the specified requirements, press the stop key to end the test.

[0165] 2) Monitoring and processing during the test

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

[0167] S2. Stop the machine at regular time intervals or number of runs to check the wear condition and surface quality of the lead screw pair to be measured.

[0168] The surface microstructure of the ball and the raceway can be observed by using an optical microscope, an electron microscope, etc.

[0169] S3. Vibration monitoring: During the fatigue life test of the sample, vibration monitoring is carried out. If any abnormality is found, the machine shall be stopped immediately, and spalling detection shall be performed on the screw to be tested 43, the nut of the screw to be tested 45, and the surface of the ball. If no fatigue failure occurs, the bearings and the installation accuracy shall be checked. After the problems are eliminated, the test shall be carried out again.

[0170] S4. Temperature monitoring: During the fatigue life test of the sample, temperature monitoring is carried out. The temperature of any part of the screw pair shall not exceed 50 °C.

[0171] If it exceeds 50 °C, the test shall be aborted, and it is necessary to check whether there are any abnormalities in the seals at both ends of the nut of the screw to be tested 45, lubrication, and installation accuracy.

[0172] If there is no abnormality, the axial load and the sample rotation speed of the screw to be tested 43 can be adjusted appropriately.

[0173] 3) Analysis of test results

[0174] For the failed products caused by inappropriate test loads, lack of lubrication, and seizure due to burning, they shall not be included in the normal failure data.

[0175] The evaluation method for the life of the micro screw pair can give a conclusion according to the requirements of customers in special fields or industry standards.

[0176] As is known by common technical knowledge, the present invention can be implemented by other embodiments that do not depart from its spiritual essence or essential features. Therefore, the above-disclosed embodiments are illustrative in all aspects and are not the only ones. All changes within the scope of the present invention or within the scope equivalent to the present invention are encompassed by the present invention.

Claims

1. A test device for the transmission efficiency and service life of a micro lead screw pair, characterized in that, The test device includes: a control system, a base, a first servo motor, a lead screw pair fixing mechanism, a test workbench, a loading workbench, and a second servo motor that are sequentially arranged on the base; The base has a pair of linear guide pairs; The lead screw pair fixing mechanism is used to install the lead screw pair to be tested, and the first connection end of the lead screw pair fixing mechanism is connected to the output end of the first servo motor through a main shaft unit, and the second connection end of the lead screw pair fixing mechanism is connected to the first connection end of the test workbench; The test workbench slides on the linear guide pair, the second connection end of the test workbench and the first connection end of the loading workbench are connected through a force balancing rod, and a force sensor is also arranged between the force balancing rod and the test workbench; The loading workbench slides on the linear guide pair, and the second connection end of the loading workbench is connected to the output end of the second servo motor through a loading lead screw pair; The control system is used to control the first servo motor and the second servo motor.

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

3. The transmission efficiency and life test device for the micro lead screw pair according to claim 1, characterized in that, The lead screw pair to be tested includes: a lead screw to be tested, a lead screw nut to be tested, balls, and a reverser installed on the lead screw nut to be tested; The lead screw nut to be tested is a long sleeve-shaped special-shaped nut, and 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 threadedly connected, and one end of the lead screw to be tested is connected to the first servo motor through the main shaft unit.

4. The transmission efficiency and life test device for the micro lead screw pair according to claim 3, characterized in that, The lead screw pair fixing mechanism includes: a connection disk, a conversion seat, a pressing plate, and a connection seat that are sequentially arranged along the length direction 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 connection disk is sleeved on the conversion seat, the first connection end of the connection disk is connected to the main shaft unit, and the second connection end of the connection disk is connected to the conversion seat; The connection seat is sleeved on the lead screw nut to be tested, the first connection end of the connection seat is connected to the first connection end of the test workbench, and the second connection end of the connection seat is connected to the lead screw nut to be tested through the pressing plate.

5. The transmission efficiency and life test device for the micro ball screw pair according to claim 1, characterized in that, The first connection end of the loading roller lead screw shaft in the loading lead screw pair is connected to the second servo motor through a lead screw front support unit, the loading roller nut in the loading lead screw pair is connected to the loading workbench, and the second connection end of the loading roller lead screw shaft is connected to the base through a lead screw rear support unit; The number of the force balancing rods is two, and they are located on both sides of the lead screw rear support unit.

6. The transmission efficiency and life test device for the micro lead screw pair according to claim 5, characterized in that, A first temperature sensor is arranged between the first servo motor and the main shaft unit; A first vibration sensor and a second temperature sensor are arranged on the test workbench; A third temperature sensor is arranged on the periphery of the device for measuring the ambient temperature; A fourth temperature sensor is arranged on the lead screw rear support unit; A second vibration sensor and a fifth temperature sensor are arranged on the loading workbench; A sixth temperature sensor is provided 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 by signals.

7. The transmission efficiency and life test device for the micro lead screw pair 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 respectively connected to the two force sensors, and is used for, when the lead screw pair to be tested is in positive transmission, summing up the total axial loading force output by the two force sensors in real time, and for, when the lead screw pair to be tested is in reverse transmission, summing up the total driving force input by the two force sensors in real time. The numerical control system is connected to the first servo motor through the first servo driver and is used for controlling the operation of the first servo motor. The first servo driver is used for collecting the real-time torque signal of the first servo motor. The numerical control system is connected to the second servo motor through the second servo driver and is used for controlling the operation of the second servo motor.

8. A method for testing the transmission efficiency of a micro ball screw pair, characterized in that, The transmission efficiency test method is applicable to the transmission efficiency and life test device of the micro lead screw pair as described in any one of claims 1-7. The transmission efficiency test method includes the following steps: 1) Positive transmission efficiency test S1. Set the master-slave mode through the control system, make the first servo motor in the main driving state, the second servo motor in the loading state, the lead screw pair to be tested drive the test workbench to make a reciprocating main movement, and the loading lead screw pair drive the loading workbench to make a reciprocating loading movement. S2. Read the torque signal input by the first servo motor in real time through the first servo driver. S3. Obtain the total axial loading force signal output by the two force sensors in real time through the total loading force processor. S4. Input the values obtained in S2 and S3 into a 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. Set the master-slave mode through the control system, make the second servo motor in the active state, the first servo motor in the driven state, the loading lead screw pair drive the loading workbench to make a reciprocating main movement, and the lead screw pair to be tested drive the test workbench to make a reciprocating loading movement. S2. Read the loading torque signal output by the first servo motor in real time through the first servo driver. S3. Obtain the total driving force signal input by the two force sensors in real time through the total loading force processor. S4. Input the values obtained in S2 and S3 into a computer, and calculate the reverse transmission efficiency of the lead screw pair to be tested according to the set formula.

9. The method for testing the transmission efficiency of the micro ball screw pair according to claim 8, characterized in that, In step 1), the computer uses the following formula to obtain the positive transmission efficiency of the lead screw pair to be tested: In the above formula: η is the positive transmission efficiency of the lead screw pair to be tested; P2 is the output power of the lead screw pair to be tested; P1 is the input power of the lead screw pair to be tested; V is the speed at which the lead screw nut drives the test workbench to move, in m / s; ω is the angular velocity at which the lead screw rotates, in rad / s; T1 is the total torque input by the first servo motor, in N.m; F1 is the total axial loading force output by the two force sensors, in N; N is the rotational speed of the lead screw to be measured, with the unit of rpm; P h is the lead of the lead screw pair to be measured, with the unit of mm; In step 2), the reverse transmission efficiency of the lead screw pair to be measured is obtained by using the following formula; In the above formula: η′ is the reverse transmission efficiency of the lead screw pair to be measured; P2′ is the output power of the lead screw pair to be measured; P1′ is the input power of the lead screw pair to be measured; ω is the angular velocity of the rotation of the lead screw to be measured, with the unit of rad / s; V is the speed at which the lead screw nut drives the test workbench to move, with the unit of m / s; T2 is the loading torque output by the first servo motor, with the unit of N·m; F2 is the total driving force input by the two force sensors, with the unit of N; N is the rotational speed of the lead screw to be measured, with the unit of rpm; P h is the lead of the lead screw pair to be measured, with the unit of mm.

10. A method for testing the service life of a micro lead screw pair, characterized in that, The life test method is applicable to the device for testing the transmission efficiency and life of the micro lead screw pair as described in any one of claims 1-7. The life test method includes the following steps: 1) Preparation and test S1. Install the lead screw pair to be measured on the lead screw pair fixing mechanism, and connect the two ends of the lead screw pair fixing mechanism to the first servo motor and the test workbench on the base respectively. Set the test parameters of the lead screw to be measured according to the technical requirements and test purposes; S2. Start the lubricating oil pump and the 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. After the loading force rises to the specified value, start the test loading, and realize the reciprocating motion of the lead screw pair to be measured according to the loading requirements of the load spectrum; S5. When the test reaches the specified requirements, press the stop key to end the test; 2) Monitoring and processing during the test S1. During the test process, the measurement and monitoring system real-time collects displacement, temperature, vibration, and noise data and transmits them to the control system; S2. Stop the machine at specified time intervals or number of runs to check the wear condition and surface quality of the lead screw pair to be measured; S3. Vibration monitoring: During the fatigue life test of the sample, conduct vibration monitoring. If any abnormality is found, stop the machine immediately, and conduct spalling detection on the surface of the lead screw to be measured, the lead screw nut to be measured, and the balls; If no fatigue failure occurs, the bearings and installation accuracy should be checked. After the problems are eliminated, the test should be carried out again; S4. Temperature monitoring: During the fatigue life test of the sample, conduct temperature monitoring. The temperature of any part of the ball screw pair cannot exceed 50 °C; If it exceeds 50 °C, the test needs to be aborted. It should be checked whether there are any abnormalities in the seals at both ends of the lead screw nut to be measured, lubrication, and installation accuracy; If there is no abnormality, the axial load and sample rotational speed of the lead screw to be measured can be appropriately adjusted; 3) Analysis of test results For the failed products caused by inappropriate test loads, lack of lubrication, and burn and jamming, they shall not be included in the normal failure data.

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