A feed transmission mechanism based on servo motor control

Abstract

The application discloses a kind of based on servo motor control's feed transmission mechanism, belong to mechanical feed transmission field, including cross drag plate, upper drag plate, cover plate, ball screw pair, front bearing seat, rear bearing seat and servo motor.The right end surface of rear bearing seat is equipped with matching groove, servo motor is directly fixed on rear bearing seat, independent motor base is saved;Between front bearing seat and cross drag plate, between rear bearing seat and cross drag plate, between slider and upper drag plate, adjusting pad plate is respectively equipped, for adjusting the double support state of screw rod and the equal height of screw rod nut and guide surface;Front, rear bearing seat is fixed on cross drag plate by screw and second positioning pin matching.This application integrates rear bearing seat and motor base into one, compact structure, coaxial degree is easy to guarantee, and accurately positioned by three pad plates on-site adjustment thickness and second positioning pin matching, effectively improve the assembly accuracy and running stability of feed transmission mechanism, suitable for the feed system of various numerical control machine tools.

Description

Technical Field

[0001] This invention relates to the field of mechanical feed transmission, and more specifically to a feed transmission mechanism based on servo motor control. Background Technology

[0002] The machine tool feed transmission mechanism is the core actuator for achieving precise positioning and high-speed motion. Its performance directly determines the overall machining accuracy, efficiency, and stability of the machine tool. Traditional feed transmission mechanisms come in various forms, and can be categorized by driving principle into types such as hydraulic cylinder-driven rack and pinion, crank-connecting rod mechanisms, and motor-driven feed. However, hydraulic cylinder-driven rack and pinion and crank-connecting rod mechanisms generally suffer from drawbacks such as complex mechanical structures, low automation, and low positioning accuracy. Traditional motor-driven sliding screw drives, on the other hand, suffer from high friction, low efficiency, rapid wear, and large backlash, making them unsuitable for high-precision machining requirements.

[0003] With the development of CNC technology, the "rotary servo motor plus ball screw" technology has become the mainstream for machine tool feed drives. Currently, some technical solutions use "rotary servo motor plus ball screw" to replace hydraulic drives or rack and pinion transmissions to improve feed accuracy. However, in existing technologies, the servo motor is usually mounted on the machine tool with a separate motor mount, while the ball screw is supported by a separate bearing housing; the motor mount and bearing housing are separate structures. This separate mounting method has the following drawbacks: the coaxiality of the motor shaft and the ball screw shaft depends on on-site assembly and debugging, making the installation process cumbersome and inconsistent; the motor mount and bearing housing occupy separate installation space, which is not conducive to the compact design of the machine tool structure; the separate structure also increases the number of parts and the cumulative assembly error.

[0004] Furthermore, in existing ball screw support structures, the bearing housing is typically fixed directly to the mounting base with screws, lacking precise positioning and adjustment methods. This makes it difficult to flexibly adjust the height of the screw axis and the relative position of the nut and guide rail surface according to actual working conditions during on-site assembly. Therefore, it is necessary to design a servo motor-controlled feed transmission mechanism with a more compact structure, easier assembly, and higher positioning accuracy. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention is proposed.

[0006] The present invention provides a feed transmission mechanism based on servo motor control, including an upper slide plate, a cover plate, a ball screw pair, a cross slide plate, a front bearing housing, a rear bearing housing, and a servo motor; The rear bearing housing is provided with a mating groove for mounting the servo motor, and the servo motor is fixedly connected to the rear bearing housing through the mating groove; Adjusting shims are provided between the front bearing housing and the cross slide, between the rear bearing housing and the cross slide, and between the nut for connecting the ball screw pair and the slider for connecting the upper slide and the upper slide. These shims are used to adjust the double support state of the ball screw pair and to adjust the height of the nut of the ball screw pair and the guide rail surface of the cross slide. The front bearing housing and the rear bearing housing are fixedly connected to the cross slide plate by screws and a matching second locating pin.

[0007] As an improvement of the present invention, the mating groove is provided on the right end face of the rear bearing housing, and the servo motor is fixedly connected to the rear bearing housing by bolts.

[0008] As an improvement of the present invention, the adjusting pad includes a first pad disposed between the slider and the upper slide plate, a second pad disposed on the bottom surface of the rear bearing seat, and a third pad disposed on the bottom surface of the front bearing seat.

[0009] As an improvement of the present invention, the adjusting shim is a flat adjusting shim.

[0010] As an improvement of the present invention, the feed transmission mechanism further includes a coupling, the coupling including a screw shaft expansion sleeve fitted outside the right side shaft of the ball screw pair, a motor shaft expansion sleeve fitted outside the output shaft of the servo motor, and a connecting sleeve covering the screw shaft expansion sleeve and the motor shaft expansion sleeve, wherein the connecting sleeve is provided with a left end cover and a right end cover at its axial ends respectively.

[0011] As an improvement of the present invention, the slider is fixedly connected to the nut of the ball screw pair by screws and a first locating pin.

[0012] As an improvement of the present invention, a front bearing is provided in the front bearing housing, and a rear bearing is provided in the rear bearing housing; a first inner spacer is provided on the inner side of the front bearing, and a second inner spacer and a third inner spacer are provided on the inner side of the rear bearing; the front end and rear end of the ball screw assembly are axially positioned by a front locking nut and a rear locking nut, respectively; a front end cover and a first oil seal are provided at the left end of the front bearing housing, and a third oil seal is provided at the right end; the front end cover is used to adjust the clearance between the inner and outer rings of the front bearing; a rear end cover is provided at the right end of the rear bearing housing, and the rear end cover is used to adjust the clearance between the inner and outer rings of the rear bearing; a second oil seal is provided at both ends of the rear bearing housing.

[0013] As an improvement of the present invention, both the front bearing and the rear bearing are angular contact ball bearings.

[0014] As an improvement of the present invention, the feed transmission mechanism further includes a pressure plate and a frame-shaped scraper. The pressure plate is fixedly connected to the side of the upper slide plate, and a sliding gap is provided between the bottom surface of the pressure plate and the upper guide rail surface of the cross slide plate. The frame-shaped scraper is arranged along the outer periphery of the upper slide plate.

[0015] As an improvement of the present invention, the feed transmission mechanism further includes a front limiting block disposed on the right side of the front bearing housing and a rear limiting block disposed on the left side of the rear bearing housing.

[0016] The beneficial effects of this invention are as follows: This invention integrates the rear bearing housing and the servo motor mounting base into one unit, eliminating the need for a separate motor housing, reducing the number of parts and assembly steps, shortening the axial installation dimensions, and facilitating a more compact machine tool design. Since the rear bearing housing also serves as the motor mounting base, the servo motor housing is directly fixed to the right end face of the rear bearing housing. The coaxiality of the motor shaft and the lead screw shaft is directly guaranteed by the machining accuracy of the bearing housing, eliminating the need for tedious alignment adjustments during on-site assembly, thus improving assembly efficiency and consistency. This invention provides adjusting shims on the bottom surfaces of the front and rear bearing housings, as well as between the slider and the upper slide plate. During on-site assembly, the thickness of these three shims can be adjusted to adjust the double-support state of the ball screw pair and the equal height of the nut and the cross slide guide surface, reducing the requirements for parts machining accuracy and improving assembly flexibility and adaptability. After the bearing housing position is properly adjusted, the front and rear bearing housings are fixed to the cross slide plate using screws and a matching second locating pin, eliminating assembly gaps and effectively preventing positional shifts in the bearing housing during use, ensuring long-term positioning accuracy and repeatability. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a cross-sectional view of a feed transmission mechanism based on servo motor control according to an embodiment of the present invention; Figure 2 yes Figure 1 Enlarged view of point A in the middle; Figure 3 yes Figure 1 Enlarged view at point B in the middle; Figure 4 This is a side view of a feed transmission mechanism based on servo motor control according to an embodiment of the present invention.

[0019] In the diagram: 1. Upper slide plate; 2. Cover plate; 3. Front locking nut; 4. First inner spacer; 5. First oil seal; 6. Front end cover; 7. Front bearing; 8. Front limit block; 9. First pad; 10. Slider; 11. First positioning pin; 12. Ball screw pair; 13. Cross slide plate; 14. Rear limit block; 15. Second inner spacer; 16. Rear bearing seat; 17. Rear bearing; 18. Third inner spacer; 19. Rear end cover; 20. Rear locking nut; 21. Left end cover; 22. Screw shaft tension sleeve 1; 23. Connecting sleeve; 24. Motor shaft tension sleeve 2; 25. Right end cover; 26. Servo motor; 27. Second pad; 28. Second positioning pin; 29. ​​Second oil seal; 30. Scraper; 31. Pressure plate; 32. Third oil seal; 33. Front bearing seat; 34. Third pad. Detailed Implementation

[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0021] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0022] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0023] like Figures 1-3The image shows an embodiment of the present invention. The present invention provides a feed transmission mechanism based on servo motor control, including an upper slide plate 1, a cover plate 2, a ball screw assembly 12, a cross slide plate 13, a front bearing housing 33, a rear bearing housing 16, and a servo motor 26. The cross slide plate 13 serves as the mounting base for the entire feed transmission mechanism. The cover plate 2 covers the upper slide plate 1 as a protective cover to protect the internal transmission components. The rear bearing housing 16 is provided with a mating groove for mounting the housing of the servo motor 26, and the servo motor 26 is fixedly connected to the rear bearing housing 16 through the mating groove. Adjusting shims are provided between the front bearing housing 33 and the cross slide 13, between the rear bearing housing 16 and the cross slide 13, and between the nut for connecting the ball screw assembly 12 and the slider 10 for connecting the upper slide 1 and the upper slide 1. Adjusting shims are provided to adjust the double support state of the ball screw assembly 12 and to adjust the nut of the ball screw assembly 12 to be at the same height as the guide surface of the cross slide 13. The front bearing housing 33 and the rear bearing housing 16 are fixedly connected to the cross slide 13 by screws and the second positioning pin 28 that is installed in conjunction with them. The ball screw assembly 12 is supported between the front bearing housing 33 and the rear bearing housing 16.

[0024] To ensure reliable support for the ball screw assembly 12, a front bearing 7 is housed in the front bearing housing 33, and a rear bearing 17 is housed in the rear bearing housing 16. Both the front bearing 7 and the rear bearing 17 are angular contact ball bearings, capable of simultaneously bearing radial and axial loads, suitable for high-speed and high-precision applications. The left end of the front bearing housing 33 has a front end cover 6, and the inner side of the front bearing 7 has a first inner spacer 4. The right end of the rear bearing housing 16 has a rear end cover 19, and the inner side of the rear bearing 17 has a second inner spacer 15 and a third inner spacer 18. Through the coordinated installation of the inner spacers, front end cover, and rear end cover, the clearance between the inner and outer rings of the bearings can be adjusted. After adjusting the bearing clearance to a suitable range, the front and rear ends of the ball screw assembly 12 are axially positioned using the front locking nut 3 and the rear locking nut 20, thus achieving double support for the ball screw assembly 12. Specifically, double support means that both ends of the ball screw are constrained by bearings within the bearing housings, allowing the screw to be positioned both axially and radially. This type of support structure, where both ends are fixed, can significantly improve the axial stiffness of the lead screw, making it suitable for high-speed rotation and high-precision machining applications. It can also reduce the bending deformation of the lead screw caused by its own weight, which helps to ensure transmission accuracy and operational stability.

[0025] To prevent bearing grease from overflowing and to prevent external contaminants from entering the bearing, the left port of the front bearing housing 33 is equipped with a first oil seal 5, and the right port of the front bearing housing 33 is equipped with a third oil seal 32; both ports of the rear bearing housing 16 are equipped with second oil seals 29. Since the front bearing housing 33 is close to the machining area, iron filings and cutting fluid generated during the cutting process are easily splashed to this area. Therefore, the third oil seal 32 further strengthens the sealing protection of the front bearing housing near the middle of the lead screw. The rear bearing housing 16 is close to the servo motor 26, and the environment is relatively clean. The second oil seal 29 is fitted on the lead screw shaft, and its end face can be observed from both ports of the rear bearing housing, thus achieving a seal on the rear bearing cavity.

[0026] The right end face of the rear bearing housing 16 is provided with a mating groove for fixing and installing the housing of the servo motor 26. The mating groove is used to achieve radial centering and axial positioning of the servo motor 26. The servo motor 26 is fixedly connected to the rear bearing housing 16 through the mating groove. The fixed connection is a bolt connection, that is, the rear bearing housing 16 also serves as the motor mounting base, eliminating the need for a separate motor mounting base, shortening the axial installation dimension, and facilitating the compact design of the machine tool structure. At the same time, the coaxiality of the motor shaft and the lead screw shaft is directly guaranteed by the machining accuracy of the rear bearing housing 16, eliminating the need for tedious centering adjustments during on-site assembly, thus improving assembly efficiency and consistency.

[0027] The output shaft of the servo motor 26 is connected to the right side shaft of the ball screw assembly 12 via a coupling. Specifically, the coupling includes a screw shaft expansion sleeve 22, a motor shaft expansion sleeve 24, and a connecting sleeve 23. The screw shaft expansion sleeve 22 is fitted over the right side shaft of the ball screw assembly 12, the motor shaft expansion sleeve 24 is fitted over the output shaft of the servo motor 26, and the connecting sleeve 23 covers both the screw shaft expansion sleeve 22 and the motor shaft expansion sleeve 24. A left end cap 21 and a right end cap 25 are respectively provided at both axial ends of the connecting sleeve 23. The coupling reliably transmits torque, compensates for coaxiality errors between the motor shaft and the screw shaft, and provides vibration damping.

[0028] To ensure the ball screw assembly 12 maintains good dual-support during operation and to ensure equal height between the screw nut and the guide surface of the cross slide 13, adjusting shims are provided between the front bearing housing 33 and the cross slide 13, between the rear bearing housing 16 and the cross slide 13, and between the slider 10 and the upper slide 1. Specifically, the adjusting shims include a first shim 9 located between the slider 10 and the upper slide 1, a second shim 27 located on the bottom surface of the rear bearing housing 16, and a third shim 34 located on the bottom surface of the front bearing housing 33. All three shims are flat adjusting shims, and their thickness is selected based on measurements taken during on-site assembly. Specifically, adjusting the dual-support state means adjusting the thickness of the shims at the bottom of the front bearing housing 33 and the rear bearing housing 16 to ensure that the height positions of the front and rear bearing housings are reasonable, preventing the screw ends from being strained or generating additional bending stress, and allowing the dual support to exert its due rigidity advantage. Specifically, "equal height" refers to adjusting and maintaining the vertical distance from the center line of the nut of the ball screw assembly 12 to the guide surface of the cross slide 13 at the design required value, that is, maintaining a constant design spacing between the screw nut and the guide surface of the cross slide 13. If the nut and the guide surface are not at equal height, the upper slide 1 will tilt or jam due to uneven force during movement, affecting machining accuracy. By adjusting the thickness of the three shims on-site, flexible adjustments can be made during the assembly stage to ensure that the requirements for the machining accuracy of the parts are met.

[0029] The slider 10 secures the upper slide plate 1 to the nut of the ball screw assembly 12 via screws and the first locating pin 11. When the lead screw of the ball screw assembly 12 rotates, the nut moves along the lead screw axis, driving the upper slide plate 1 to move linearly along the upper guide surface of the cross slide plate 13 via the slider 10, thereby achieving the feed motion. The linear movement distance of the upper slide plate 1 is related to the lead of the ball screw assembly 12; specifically, the lead refers to the distance the nut moves linearly when the lead screw rotates one revolution.

[0030] like Figure 4 As shown, Figure 4 This is a side view of the present invention. The feed transmission mechanism based on servo motor control of the present invention further includes a pressure plate 31 and a frame-type scraper plate 30. The pressure plate 31 is fixedly connected to the side of the upper slide plate 1, and a sliding gap is provided between the bottom surface of the pressure plate 31 and the upper guide rail surface of the cross slide plate 13. The frame-type scraper plate 30 is arranged along the outer periphery of the upper slide plate 1. The function of the pressure plate 31 is to prevent the cutting tool mounted on the upper slide plate 1 from tilting or flipping during cutting, thereby improving the stability of the cutting process. The function of the frame-type scraper plate 30 is to promptly clean up the iron filings generated during the machining process, preventing the iron filings from scratching the upper guide rail surface of the cross slide plate 13, and ensuring the accuracy and service life of the guide rail surface.

[0031] Furthermore, the servo motor-controlled feed transmission mechanism of the present invention also includes a front limiting block 8 disposed on the right side of the front bearing housing 33 and a rear limiting block 14 disposed on the left side of the rear bearing housing 16. The limiting blocks are used to limit the travel range of the upper slide plate 1 to prevent the upper slide plate 1 from moving beyond its travel range and causing collision or damage.

[0032] The working principle of this invention is as follows: After the servo motor 26 is powered on, its output shaft rotates, driving the ball screw pair 12 to rotate synchronously through the coupling. The rotational motion of the screw is converted into the linear motion of the nut through the rolling contact of the steel balls between the screw and the nut. The nut drives the upper slide plate 1 to move linearly along the upper guide rail surface of the cross slide plate 13 through the slider 10, thereby realizing the feed motion. During the entire working process, the front and rear double support structure of the ball screw pair 12 ensures the rigidity and stability of the screw; the three adjusting shims ensure the rationality of the double support state and the equal height relationship between the nut and the guide rail surface; the second positioning pin 28 installed in conjunction ensures the precise positioning of the front bearing seat 33 and the rear bearing seat 16; the pressure plate 31 prevents the upper slide plate 1 from tilting and flipping; the frame-type scraper 30 cleans the iron filings in time and protects the guide rail surface; the limit block ensures that the upper slide plate 1 moves within the safe stroke range.

[0033] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A feed transmission mechanism based on servo motor control, comprising an upper slide plate (1), a cover plate (2), a ball screw pair (12), a cross slide plate (13), a front bearing housing (33), a rear bearing housing (16), and a servo motor (26), characterized in that, The rear bearing housing (16) is provided with a mating groove for mounting the servo motor (26), and the servo motor (26) is fixedly connected to the rear bearing housing (16) through the mating groove; Between the front bearing housing (33) and the cross slide plate (13), between the rear bearing housing (16) and the cross slide plate (13), and between the nut for connecting the ball screw pair (12) and the slider (10) for connecting the upper slide plate (1) and the upper slide plate (1), there are adjustment pads for adjusting the double support state of the ball screw pair (12) and adjusting the nut of the ball screw pair (12) and the guide surface of the cross slide plate (13) to be at the same height. The front bearing housing (33) and the rear bearing housing (16) are fixedly connected to the cross slide plate (13) by screws and a matching second locating pin (28).

2. The feed transmission mechanism based on servo motor control according to claim 1, characterized in that, The mating groove is provided on the right end face of the rear bearing housing (16), and the servo motor (26) is fixedly connected to the rear bearing housing (16) by bolts.

3. The feed transmission mechanism based on servo motor control according to claim 1, characterized in that, The adjusting pads include a first pad (9) disposed between the slider (10) and the upper slide plate (1), a second pad (27) disposed on the bottom surface of the rear bearing seat (16), and a third pad (34) disposed on the bottom surface of the front bearing seat (33).

4. The feed transmission mechanism based on servo motor control according to claim 3, characterized in that, The adjusting shim is a flat adjusting shim.

5. The feed transmission mechanism based on servo motor control according to claim 1, characterized in that, The feed transmission mechanism also includes a coupling, which includes a screw shaft expansion sleeve (22) fitted outside the right side shaft of the ball screw pair (12), a motor shaft expansion sleeve (24) fitted outside the output shaft of the servo motor (26), and a connecting sleeve (23) covering the screw shaft expansion sleeve (22) and the motor shaft expansion sleeve (24). The connecting sleeve (23) is provided with a left end cover (21) and a right end cover (25) at its two axial ends.

6. The feed transmission mechanism based on servo motor control according to claim 1, characterized in that, The slider (10) is fixedly connected to the upper slide plate (1) and the nut of the ball screw pair (12) by screws and the first positioning pin (11).

7. The feed transmission mechanism based on servo motor control according to claim 1, characterized in that, The front bearing housing (33) is provided with a front bearing (7), and the rear bearing housing (16) is provided with a rear bearing (17). The front bearing (7) is provided with a first inner spacer (4), and the rear bearing (17) is provided with a second inner spacer (15) and a third inner spacer (18). The front end and rear end of the ball screw assembly (12) are axially positioned by a front locking nut (3) and a rear locking nut (20), respectively. The left end of the front bearing housing (33) is provided with a front end cover (6) and a first oil seal (5), and the right end is provided with a third oil seal (32). The front end cover (6) is used to adjust the gap between the inner and outer rings of the front bearing (7). The right end of the rear bearing housing (16) is provided with a rear end cover (19). The rear end cover (19) is used to adjust the gap between the inner and outer rings of the rear bearing (17). The two ends of the rear bearing housing (16) are provided with a second oil seal (29).

8. The feed transmission mechanism based on servo motor control according to claim 7, characterized in that, Both the front bearing (7) and the rear bearing (17) are angular contact ball bearings.

9. The feed transmission mechanism based on servo motor control according to claim 1, characterized in that, The feed transmission mechanism also includes a pressure plate (31) and a frame-type scraper (30). The pressure plate (31) is fixedly connected to the side of the upper slide plate (1), and a sliding gap is provided between the bottom surface of the pressure plate (31) and the upper guide rail surface of the cross slide plate (13). The frame-type scraper (30) is arranged along the outer periphery of the upper slide plate (1).

10. The feed transmission mechanism based on servo motor control according to claim 1, characterized in that, The feed transmission mechanism also includes a front limiting block (8) located on the right side of the front bearing housing (33) and a rear limiting block (14) located on the left side of the rear bearing housing (16).

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