An axial loading structure for a ball screw pair with staggered vertical arrangement

Abstract

This invention discloses an axial loading structure for a ball screw pair with staggered vertical arrangement, including a test ball screw module, a test ball screw module, and an axially connected loading module. A tension / compression sensor in the axially connected loading module connects the worktables of the test ball screw module and the test ball screw module. The axial load is adjusted by controlling the output torque of the servo motor in the axially connected loading module. It exhibits stable axial loading capability in dynamic reliability testing of the ball screw, effectively simulating the variable axial load condition of the ball screw under actual operation.

Description

Technical Field

[0001] This invention belongs to the technical field of dynamic characteristic testing and reliability assessment of ball screw pairs, specifically relating to an axial loading structure for ball screw pairs with staggered upper and lower arrangements. Background Technology

[0002] CNC machine tools, as the "mother machines" of the manufacturing industry, are the core manufacturing foundation for aerospace equipment, rail transit equipment, marine engineering equipment, and other related intelligent equipment. To ensure the high precision, high performance, and long lifespan of manufacturing equipment in other fields, higher manufacturing requirements are placed on these mother machines. Ball screw assemblies, as high-speed, high-precision positioning and transmission components, are widely used in the servo transmission systems of high-end CNC machine tools. While static indicators of ball screw assemblies are generally tested before shipment, their dynamic performance and reliability largely determine the overall performance of the CNC machine tool. Therefore, research on the dynamic reliability of ball screw assemblies under actual operating conditions is highly valuable.

[0003] In actual use, ball screws can experience variable speed and variable load. Variable speed can be easily achieved by controlling the speed of the motor, but applying variable axial load to a moving worktable is quite difficult. Current research mainly focuses on three dynamic loading methods: hydraulic cylinder loading, gear and rack loading, and horizontal ball screw loading.

[0004] Hydraulic loading methods have disadvantages such as long axial distance and high cost due to the need for a matching hydraulic system.

[0005] Gear and rack loading has the disadvantages of low effective travel of the lead screw and high torsional torque.

[0006] Horizontal ball screw loading has disadvantages such as bidirectional offset torque, uneven force on the worktable, and low effective stroke.

[0007] Therefore, designing a ball screw pair loading test bench with long effective stroke, small offset torque, compact structure and low cost is of great significance for improving experimental accuracy and efficiency. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide an axial loading structure for a ball screw pair with staggered upper and lower arrangement, which addresses the shortcomings of the prior art and solves the technical problems of multi-directional offset torque, limited effective stroke and high experimental cost of existing loading devices.

[0009] The present invention adopts the following technical solution:

[0010] An axial loading structure for a ball screw pair with staggered vertical arrangement includes a test ball screw module. The main worktable of the test ball screw module is connected to the test worktable of the test ball screw module through a tension / compression sensor of the axial connection loading module. The active screw on the main worktable and the test screw on the test worktable are staggered vertically. According to the axial loading requirements, the axial load capacity in the dynamic reliability test experiment of the ball screw is adjusted by controlling the torque of the axial connection loading module, simulating the variable axial load condition of the ball screw under actual operation.

[0011] Specifically, the test ball screw module includes a fixed base, which is set on the test bench base. One end of the fixed base is equipped with a drive servo motor. The output shaft of the drive servo motor is connected to the drive screw via a coupling. The drive screw is fitted with a drive nut, which is connected to the main worktable. The motor drives the drive screw to rotate, thereby moving the main worktable.

[0012] Furthermore, the fixed end circumferential surface of the active lead screw is tightly fitted with the inner ring of the bearing inside the main fixed end component, and the supporting side circumferential surface of the active lead screw is tightly fitted with the inner ring of the bearing inside the main supporting end component. The main supporting end component is fixedly connected to the test bench base through the supporting base.

[0013] Specifically, the test ball screw module includes a test servo motor, which is symmetrically arranged with the drive servo motor of the test ball screw module. The output shaft of the test servo motor is connected to the support end component via a test coupling and a test screw. A test nut is fitted on the test screw, which is used to connect to the test worktable.

[0014] Furthermore, the output shaft of the test servo motor is connected to the shaft end of the test lead screw via a test coupling. The circumferential surface of the fixed end of the test lead screw is tightly fitted with the inner ring of the bearing in the fixed end component, and the circumferential surface of the support side of the test lead screw is tightly fitted with the inner ring of the bearing in the support end component.

[0015] Furthermore, the driving screw and driving nut, as well as the test screw and test nut, are all connected by ball screw pairs.

[0016] Furthermore, the test bench base is equipped with guide rails, and sliders are installed inside the guide rails. The main workbench and the auxiliary workbench are respectively connected to the corresponding sliders.

[0017] Furthermore, the test bench base is mounted on a T-slot base.

[0018] Specifically, the axial connection loading module includes tension and compression sensors, which are respectively installed in grooves on opposite sides of the main worktable and the auxiliary worktable.

[0019] Furthermore, there is an axial gap between the main workbench and the auxiliary workbench.

[0020] Compared with the prior art, the present invention has at least the following beneficial effects:

[0021] An axial loading structure for a ball screw pair with staggered vertical arrangement is disclosed. Based on an axial connection loading module, a test ball screw module and a test ball screw module are connected. The staggered installation of the test and test ball screw modules eliminates horizontal offset torque, increases effective stroke, and reduces experimental costs, meeting the requirements for high accuracy and high efficiency in experimental testing. The fixed end base of the active ball screw and the support end component of the test ball screw are designed separately, avoiding the influence of vibration at the support end of the test ball screw on the fixed end base of the active ball screw. The test worktable and the active worktable are designed separately, connected by threaded holes at both ends of the tension / compression sensors, reducing the influence of the transmission characteristics of the test ball screw on the transmission characteristics of the active ball screw, which is more beneficial for the study of the transmission characteristics of the active ball screw. The test bench and the active bench are equipped with grooves facing each other and countersunk holes on both sides to facilitate the installation of tension and compression sensors and cable layout. The active and passive benches share the same linear guide pair, and the two benches are arranged parallel between the two lead screws, eliminating the offset torque in the horizontal direction and making the offset torque in the vertical direction controllable. This effectively reduces the impact of the offset torque caused by the applied axial load on the performance testing of the active lead screw. Each of the active and passive benches is equipped with a grating probe, which can measure the accuracy of the lead screw separately, eliminating interference between the two lead screws.

[0022] Furthermore, the fixed-end base adopts an extended and thickened structure. The top of the fixed-end base is connected to the motor base with screws, and the bottom of the fixed-end base is connected to the test bench base with four countersunk screws. This extended and thickened structure effectively reduces vibration at the fixed support end and improves transmission stability for ball screws with installation height differences. The fixed-end base has a through hole in the axial direction, the size of which is twice the nominal diameter of the ball screw, providing axial space for the installation and adjustment of the test ball screw. The support-end base adopts a non-extended and non-thickened structure. The top of the support-end base is connected to the main support component with screws. The bottom is connected to the test bench base by four countersunk screws. Since the fixed end mainly bears the axial load, the thickened but not extended support end base structure can improve the effective stroke of the active ball screw without reducing the load-bearing capacity. The support end base is provided with a through hole in the axial direction. The size of the through hole is twice the nominal diameter of the screw. The test screw passes through the through hole and is installed on the outside with the fixed end component. The staggered installation method can improve the effective stroke of the active ball screw. At the same time, the staggered side is set at the support end of the active screw, leaving a certain axial installation space for the fixed end base of the active screw, ensuring the support strength of the fixed end of the active screw.

[0023] Furthermore, the drive servo motor and the accompanying servo motor are arranged approximately symmetrically, avoiding the increase in the width of the test bench and the imbalance in mass caused by installation on the same side. This makes the entire structure more compact, improves the structural stability of the entire system, and reduces costs.

[0024] Furthermore, the two ball screw pairs serve as testing and loading components, respectively. Based on the efficient forward and reverse transmission characteristics of the ball screw pairs, dynamic loading can be achieved during the movement of the worktable. At the same time, the arrangement of two ball screws allows for the generation of two ball screw precision degradation test samples in a single test, thus improving testing efficiency.

[0025] Furthermore, an extended and heightened slider is connected to the left and right sides of both the main worktable and the auxiliary worktable, which ensures the slider's load-bearing capacity while increasing the effective stroke of the active lead screw.

[0026] Furthermore, the T-slot base is securely connected to the test bench base via T-nuts. The T-slot base is supported by six adjustable level anchor bolts, featuring a low center of gravity and heavy weight, thus improving the stability of the entire test bench.

[0027] Furthermore, by monitoring the axial force of the tension and compression sensors, the output torque of the servo motor is adjusted, thereby achieving precise active axial force loading of the ball screw.

[0028] Furthermore, the main workbench and the auxiliary workbench have axial operating clearances to ensure space for the installation of communication cables for the tension and compression sensors.

[0029] In summary, this invention demonstrates stable axial loading capability in dynamic reliability testing of ball screws. For specific scenarios, the corresponding support dimensions can be modified according to the nominal diameter and length of the ball screw. Tension and compression sensors can be selected based on the axial load magnitude. Through the above structure, the variable axial load condition of the ball screw under actual operation can be effectively simulated.

[0030] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0031] Figure 1 A schematic diagram of the overall structure of the axial loading device for a ball screw pair;

[0032] Figure 2 A schematic diagram of misaligned installation of the axial loading device for a ball screw.

[0033] Figure 3 This is a partial schematic diagram of the loading structure.

[0034] The components include: 1. Drive servo motor; 2. Main fixed end component; 3. Drive screw; 4. Test bench; 5. First limit baffle; 6. Main workbench; 7. Second limit baffle; 8. Drive nut; 9. Main nut sleeve; 10. Limit switch; 11. Drop ring; 12. Main support component; 13. Test fixed end component; 14. Test servo motor; 15. Test bench base; 16. T-slot base; 17. Linear guide rail; 18. Guide rail limiter; 19. Test nut; 20. Accompanying... 21. Test nut sleeve; 22. Grating ruler; 23. Accompanying grating probe assembly; 24. Main grating probe assembly; 25. Accompanying lead screw; 26. Main support base; 27. Anchor bolt assembly; 28. Accompanying coupling; 29. ​​Main coupling; 30. Main fixed end base; 31. Accompanying support end component; 32. Anti-collision block; 33. Tension and compression sensor; 34. Positioning clamping block; 35. T-nut assembly; 36. Main worktable loading screw; 37. Accompanying worktable loading screw; 38. Slider. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "one side," "one end," and "one side," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0037] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0038] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0039] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0040] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0041] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0042] This invention provides an axial loading structure for a ball screw pair with staggered vertical alignment. The test ball screw module worktable is connected to the auxiliary ball screw module worktable via tension and compression sensors connected to the axial loading module. The axial load is adjusted by controlling the torque of the auxiliary servo motor of the axially connected loading module. It exhibits stable axial loading capability in dynamic reliability testing of the ball screw, effectively simulating the variable axial load condition of the ball screw under actual operation.

[0043] The ball screw test module includes a servo motor 1, a main coupling 28, a main fixed end component 2, a main fixed end base 29, a drive screw 3, a drive nut 8, a main nut sleeve 9, a main worktable 6, a grating ruler 21, a main grating probe assembly 23, a main support end component 12, and a main support base 25. The motor drives the screw to rotate, thereby moving the main worktable.

[0044] Please see Figure 1 ,

[0045] The output shaft of the drive motor 1 is connected to the shaft end of the drive screw 3 via the coupling 28. The circumferential surface of the fixed end of the drive screw 3 is tightly fitted with the inner ring of the bearing in the main fixed end component 12, and the circumferential surface of the support side of the drive screw 3 is tightly fitted with the inner ring of the bearing in the main support end component 12.

[0046] The top surface of the main fixed end base 29 is provided with four threaded holes, and the main fixed end component 2 is fastened to the main fixed end base 29 by four screws.

[0047] The main fixed end base 29 has protrusions on both sides, and each protrusion has two countersunk holes. The test bench base 15 has four symmetrically arranged mounting threaded holes on the fixed side. The main fixed end base 29 is installed on the test bench base 15 through the countersunk holes on both sides by four countersunk screws.

[0048] The top surface of the main support base has two threaded holes, and the main support end component 12 is fastened to the main support base 25 by two screws.

[0049] The main support base 25 has protrusions on both sides, and each protrusion has two countersunk holes. The test bench base 15 has four symmetrically arranged mounting threaded holes on the support side. The main support base 25 is installed on the test bench base 15 through the countersunk holes on both sides by four countersunk screws.

[0050] Four sliders 37 are symmetrically mounted on guide rails 17 by screws. Guide rails 17 are fixedly mounted on the test bench base 15. The main worktable 6 has a total of 8 countersunk holes and 6 threaded holes symmetrically positioned on both sides. The main worktable 6 is mounted on two sliders 37 by eight countersunk screws.

[0051] The main worktable 6 has grooves on both sides in the horizontal direction. On one side, the grating probe assembly 23 is installed by 6 screws, and on the other side, the second limit baffle 7 for the limit switch is installed by 4 screws.

[0052] The active lead screw 3 and the active nut 8 are connected by a ball screw pair. The main nut sleeve 9 has a threaded hole on one side that corresponds to the standard mounting hole of the active nut 8. The main nut sleeve 9 and the active nut 8 are fastened by circumferential screws. The active nut sleeve 9 has bosses on both sides, and each boss has three countersunk holes. The active nut sleeve 9 is installed on the upper side of the main worktable 6 by six countersunk screws.

[0053] The ball screw module includes a test servo motor 14, a test coupling 27, a test fixed end component 13, a test screw 24, a test nut sleeve 20, a test worktable 4, a grating ruler 21, a test grating probe assembly 22, and a test support end component 30.

[0054] Please see Figure 2 The output shaft of the test servo motor 14 is connected to the shaft end of the test lead screw 24 via the test coupling 27. The circumferential surface of the fixed end of the test lead screw 24 is tightly fitted with the inner ring of the bearing in the test fixed end component 13, and the circumferential surface of the support side of the test lead screw 24 is tightly fitted with the inner ring of the bearing in the test support end component 30.

[0055] Both the main fixed base 29 and the main support base 25 have through holes on one axial side, through which the test lead screw 24 can be installed. The test lead screw 24 and the active lead screw 3 are parallel vertically and offset front to back in space.

[0056] The test bench base 15 has four symmetrically arranged mounting threaded holes at the test fixture position, and the test fixture component 13 is mounted on the test bench base 15 by four countersunk screws.

[0057] The test bench base 15 has two symmetrically arranged mounting threaded holes on the test support side, and the test support end component 30 is installed on the test bench base 15 by two countersunk screws.

[0058] The testing workbench 4 has 14 countersunk holes symmetrically positioned on both sides. The testing workbench 4 is mounted on the other two sliders 37 using eight of the countersunk screws.

[0059] The test bench 4 has grooves on both sides. On one side, the grating probe assembly 22 is installed by 6 screws, and on the other side, the first limit baffle 5 for the limit switch is installed by 4 screws.

[0060] The test screw 24 and the test nut 19 are connected by a ball screw pair. The test nut sleeve 20 has a threaded hole on one side that corresponds to the standard mounting hole of the test nut 19. The test nut sleeve 20 and the test nut 19 are fastened together by circumferential screws. The test nut sleeve 20 is inverted T-shaped and has bosses on both sides. Each boss has three countersunk holes. The test nut sleeve 20 is installed on the underside of the test workbench 4 by six countersunk screws.

[0061] The axial connection loading module includes a main worktable 6, a test worktable 4, a tension / compression sensor 32, a test servo motor 14, a main worktable loading screw 35, and a test worktable loading screw 36.

[0062] Please see Figure 3 The main workbench 6 and the auxiliary workbench 4 are provided with grooves on both longitudinal sides. A through countersunk hole is provided in the groove on the opposite side. A tension / compression sensor 32 is placed in the groove on the inner side of the main workbench 6 and the auxiliary workbench 4. Countersunk screws are installed in the countersunk holes in the two workbenches and connected to the tension / compression sensor 32, the main workbench 6 and the auxiliary workbench 4 by screws to realize the measurement of axial force at both ends. The main workbench 4 and the auxiliary workbench 6 have an axial operating clearance to ensure the installation space of the communication cable of the tension / compression sensor 32.

[0063] Preferably, in the dynamic reliability test of the ball screw pair, the upper side of the axial loading structure of the screw is the test ball screw module, and the lower side is the auxiliary ball screw module. If the active control modes of the two modules are interchanged, a similar modified scheme will be generated, which will exchange the control modes of the drive servo motor 1 and the auxiliary servo motor 14. That is, the upper screw is the axial force loading screw, and the lower screw is the loaded screw. This scheme can also realize variable axial loading on the lower ball screw pair.

[0064] The working principle of the axial loading structure of the ball screw pair with staggered vertical arrangement of the present invention is as follows:

[0065] The drive servo motor 1 drives the main coupling 28 to rotate, and the main coupling 28 drives the drive screw 3 to rotate. Since the ball screw pair can convert the rotational motion into linear motion, the rotation of the drive screw 3 drives the drive nut 8, the drive nut sleeve 9 and the main worktable 6 to move to the left or right. The main worktable 6 is connected to the test worktable 4 through the tension and compression sensor, so the test worktable 4 moves in the same direction as the main worktable 6.

[0066] The movement of the test workbench 4 drives the movement of the test nut sleeve 20 and the test nut 19. Because the ball screw pair can convert linear motion into rotary motion, the test screw 24 rotates in the same direction as the drive servo motor 1.

[0067] In order to provide axial load to the active lead screw 3, the test servo motor 14 outputs torque in the opposite direction to the rotation of the test lead screw 24. By monitoring the axial force measurement value of the tension and compression sensor, the output torque of the test servo motor 14 is adjusted to achieve precise axial load.

[0068] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0069] To illustrate the specific application scenarios and effects of the axial force loading device of the present invention, an example is taken of a certain type of ball screw with a nominal diameter of 25mm and a lead of 8mm. An accelerated performance degradation experiment was conducted on this type of screw. In order to simulate the variable speed and variable load situation that exists in the actual operation of the screw, the length of the active screw 3 and the test screw 24 of this type is 1100mm. The rated speed of the driving servo motor 1 is 2000r / min, the maximum output torque of the test servo motor 14 is 9N.M, and the maximum required axial load is 3000N.

[0070] The working load direction of the ball screw should be as close as possible to the center of the screw being loaded. Deviating from the center will cause a certain offset torque, which will accelerate the wear and vibration of the linear guide, interfering with the performance degradation test of the ball screw pair. To avoid this problem, the structure of this invention is used for loading. The vertical distance between the active screw 3 and the test screw 24 is 93mm, and the horizontal offset distance is 0, eliminating the horizontal offset torque. The distance from the center of the tension / compression sensor 32 to the rotation center of the active screw 3 is 47mm, and the maximum axial force displayed by the tension / compression sensor 32 is 3000N. Because the main worktable 6, the test worktable 4, and the tension / compression sensor 32 are located between the two screws, the offset torque is minimized while the overall structure is more compact. Therefore, the torque on the vertical plane is equal to the product of the axial force displayed by the tension / compression sensor 32 and the distance from the center of the tension / compression sensor 32 to the rotation center of the active lead screw 3. The maximum offset torque is 141 N.M, which is much smaller than the rated torque of the guide rail of 408 N.M. Given that the actual axial load is less than 3000 N, this upper and lower design structure has a better loading effect.

[0071] To better study the performance degradation of the lead screw under uniform loading, the effective stroke of the lead screw needs to be as long as possible. Therefore, to address this issue, the active lead screw 3 and the test lead screw 24 are offset by 108mm in the horizontal front-to-back direction. The test lead screw 24 is installed through the main support end base 25, reducing the impact of vibration at the support end of the test lead screw on the fixed end base of the active ball screw. The maximum width of both the main worktable 6 and the test worktable 4 is set to 133mm, using an extended and heightened single-slider load-bearing system. This increases the axial space without reducing the load-bearing capacity. Under this offset installation, the effective working stroke can reach 675mm, which better meets the working stroke requirements of the test experiment.

[0072] To meet different loading requirements, the output torque of the servo motor 14 can be adjusted to obtain different axial loads. For different types of lead screws with varying axial loading requirements, other standard components can be selected based on the diameter and length of the lead screw, and the design can be carried out according to the structural form of this invention.

[0073] In summary, the axial loading structure of the ball screw pair with staggered vertical arrangement of the present invention exhibits stable axial loading capacity and a large working stroke in the dynamic reliability test of the ball screw. For specific scenarios, the corresponding support dimensions can be modified according to the nominal diameter and length of the ball screw, and tension and compression sensors can be selected based on the axial load magnitude. By installing and debugging the above structure, the variable axial load condition of the ball screw under actual operation can be effectively simulated.

[0074] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. An axial loading structure for a ball screw pair with staggered vertical alignment, characterized in that, This includes a test ball screw module, a test ball screw module, and an axial connection loading module; The main worktable (6) of the test ball screw module is connected to the test worktable (4) of the test ball screw module through the tension and compression sensor (32) of the axial connection loading module. The active screw (3) on the main worktable (6) and the test screw (24) on the test worktable (4) are arranged parallel vertically and offset horizontally, and the main worktable (6) and the test worktable (4) are axially spaced. They adopt a split structure. The test ball screw module includes a fixed base (29), which is set on the test bench base (15). 9) is equipped with a drive servo motor (1) at one end. The output shaft of the drive servo motor (1) is connected to the active lead screw (3) via a coupling (28). An active nut (8) is fitted on the active lead screw (3). The active nut (8) is connected to the main worktable (6). The drive servo motor drives the active lead screw (3) to rotate, thereby driving the main worktable (6) to move. A guide rail (17) is provided on the test bench base (15). A slider (37) is provided inside the guide rail (17). The main worktable (6) and the test bench (4) are respectively connected to the corresponding slider (37). The test ball screw module includes a test servo motor (14), which is symmetrically arranged with the drive servo motor (1) of the test ball screw module. The output shaft of the test servo motor (14) is connected to the test screw (24) via a test coupling (27). The test screw (24) is fitted with a test nut (19), which is used to connect to the test workbench (4). According to the axial load requirement, the output torque of the test servo motor (14) is controlled to adjust the axial load applied to the active screw (3) to simulate the variable axial load condition of the ball screw under actual operation.

2. The axial loading structure of the ball screw pair with staggered upper and lower arrangement according to claim 1, characterized in that, The fixed end circumferential surface of the active screw (3) is tightly fitted with the inner ring of the bearing inside the main fixed end component (2), and the supporting side circumferential surface of the active screw (3) is tightly fitted with the inner ring of the bearing inside the main support end component (12). The main support end component (12) is fixedly connected to the test bench base (15) through the support base (25).

3. The axial loading structure of the ball screw pair with staggered upper and lower arrangement according to claim 1, characterized in that, The output shaft of the test servo motor (14) is connected to the shaft end of the test lead screw (24) via the test coupling (27). The circumferential surface of the fixed end of the test lead screw (24) is tightly fitted with the inner ring of the bearing in the test fixed end component (13), and the circumferential surface of the support side of the test lead screw (24) is tightly fitted with the inner ring of the bearing in the test support end component (30).

4. The axial loading structure of the ball screw pair with staggered upper and lower arrangement according to claim 1, characterized in that, The active lead screw (3) and the active nut (8), and the test lead screw (24) and the test nut (19) are all connected by ball screw pairs.

5. The axial loading structure of the ball screw pair with staggered upper and lower arrangement according to claim 1, characterized in that, The test bench base (15) is set on the T-slot base (16).

6. The axial loading structure of the ball screw pair with staggered upper and lower arrangement according to claim 1, characterized in that, The axial connection loading module includes a tension and compression sensor (32), with both ends of the tension and compression sensor (32) respectively set in the grooves on the opposite side of the main worktable (6) and the auxiliary worktable (4).

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