A double-sided feeding type horizontal worktable

Abstract

The application discloses a double-side feeding type horizontal workbench and belongs to the technical field of milling machine processing. The workbench comprises a bed base, a workbench main body, a guide mechanism and a feeding driving system. Two differential linkage elastic synchronizers are arranged in the feeding driving system. Each of the synchronizers is composed of a planetary differential gear train and an elastic balance assembly. Pure mechanical torque balance and synchronous error dynamic correction between the two sides of the ball screws are realized. Mechanical synchronization of double-side driving is realized. The self-adaptive characteristics of full passivity, zero delay and maintenance-free are achieved. The whole dynamic correction process is completely completed by the mechanical structure independently, and the electrical control system is not needed. The response speed is far superior to the electronic servo scheme, and the workbench is not affected by electromagnetic interference.

Description

Technical Field

[0001] This application relates to the field of milling machine technology, and more specifically, to a double-feed horizontal worktable. Background Technology

[0002] In equipment such as horizontal boring and milling machines, the feed drive method of the horizontal worktable directly affects the machining accuracy and stability of the machine tool. Currently, the industry standard process generally adopts a layout where a single motor drives a single ball screw pair through a coupling. Although this single-sided drive structure is simple, the driving force acts on one side of the worktable, which inevitably generates an additional yaw torque. Under long stroke, high load, or high speed conditions, this torque will cause uneven wear between the guide rail and the ball screw, and induce torsional deformation and positioning vibration, which seriously affects the accuracy retention.

[0003] To address this issue, the industry has proposed a dual-side dual-servo motor electronic synchronous drive solution. This solution uses two independent servo drive systems and relies on closed-loop feedback from a grating ruler and complex control algorithms to maintain synchronization. However, this approach has fundamental drawbacks: high system cost, complex electrical debugging, susceptibility to electromagnetic interference, and the limited response bandwidth of the electronic servo motors cannot completely eliminate the risk of loss of synchronization and oscillation under sudden off-center load impacts. More importantly, neither of the above two solutions possesses the adaptive load distribution capability of the mechanical body, and therefore cannot solve the problem of uneven force distribution on the guide rail caused by off-center loads at the structural level.

[0004] In view of this, a double-feed horizontal worktable is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a double-feed horizontal worktable to solve the problems mentioned in the background art.

[0006] The present invention provides the following technical solution: a double-sided feed horizontal worktable, comprising a bed base, a worktable body, a guide mechanism, and a feed drive system;

[0007] The guiding mechanism includes a first guide rail and a second guide rail that are fixed on both sides of the bed base and extend in parallel. The bottom sides of the worktable body are slidably engaged with the first guide rail and the second guide rail, respectively.

[0008] The feed drive system includes a servo motor, a T-type commutator, two parallel drive shafts, two differential linkage elastic synchronizers, two ball screws, and a nut seat adapted to the thread of the ball screws.

[0009] The servo motor is driven and connected to the input end of the T-type commutator via a speed reducer;

[0010] The two output ends of the T-type commutator are respectively coaxially and fixedly connected to one end of the two drive shafts;

[0011] The other ends of the two drive shafts are respectively coaxially and fixedly connected to the input ends of the two differential linkage elastic synchronizers;

[0012] The output ends of the two differential linkage elastic synchronizers are respectively coaxially and fixedly connected to the shaft ends of the two ball screws;

[0013] The differential linkage elastic synchronizer includes a housing and a planetary differential gear train and an elastic balance assembly disposed inside the housing;

[0014] The planetary differential gear train includes an input ring gear, an output sun gear, a double planetary gear set, and a planet carrier. The input ring gear forms the input end and is coaxially fixed to the corresponding drive shaft. The output sun gear forms the output end and is coaxially fixed to the corresponding ball screw. The planet carrier is rotatably supported within the housing.

[0015] The elastic balancing assembly includes an end face cam fixed to the planet carrier, a spring seat fixed to the housing, and an elastic element group compressed between the spring seat and the end face cam. The elastic element group is configured to apply an axial biasing force to the end face cam to force the planet carrier to remain at the zero angle position in a free state.

[0016] When the loads on the two ball screws differ, the planetary carrier of the corresponding differential linkage elastic synchronizer can overcome the bias force of the elastic element group and rotate. Through the absorption and compensation of the planetary differential gear system, the torque balance and dynamic correction of the synchronization error of the ball screws on both sides are realized.

[0017] According to the above technical solution, the elastic element group is a pair of high-stiffness disc spring groups, and the roller follower keeps in contact with the curved surface of the end face cam to convert the axial elastic force of the disc spring group into a circumferential restoring torque on the planetary carrier.

[0018] According to the above technical solution, a viscous damping cavity is further provided between the end face cam and the housing, and the viscous damping cavity is filled with a damping medium to absorb the vibration energy during the offset process of the end face cam.

[0019] According to the above technical solution, a limiting pin fixed to the housing is also provided on the rotation path of the planetary carrier to limit the maximum elastic torsion angle of the planetary carrier.

[0020] According to the above technical solution, the limiting pin includes a threaded adjusting shaft threadedly connected to the housing and a push rod slidably disposed in the threaded adjusting shaft via an elastic element. The push rod elastically abuts against the planetary carrier under the action of the elastic element, which is used to provide auxiliary elastic reset constraint for the planetary carrier in the rotating state and to buffer the impact of the planetary carrier on the limiting pin.

[0021] According to the above technical solution, the T-type commutator is a spiral bevel gear commutator, in which the internal bevel gear pair distributes the input torque of the servo motor to the two parallel transmission shafts at the same speed and in the same direction in a rigid meshing manner.

[0022] According to the above technical solution, the nut seat is a double nut structure. When a wear gap occurs between the ball screw and the nut seat, the double nut structure nut seat is configured to automatically fit against the thread surface of the ball screw to achieve symmetrical pre-tightening on both sides of the thread groove of the ball screw.

[0023] According to the above technical solution, the horizontal worktable also includes a ball screw thermal expansion linkage compensation mechanism. The ball screw thermal expansion linkage compensation mechanism constructs the end bearing seat of the ball screw on the right side as a floating bearing seat that can slide along the axial direction, and couples the fixed bearing seat of the ball screw on the left side with the floating bearing seat through a mechanical compensation lever.

[0024] According to the above technical solution, the fulcrum of the mechanical compensation lever is located in the middle, and is used to transmit the displacement difference to the floating bearing seat according to a preset ratio when the ball screws on the left and right sides generate unequal thermal elongation, so as to drive the floating bearing seat to slide axially, thereby maintaining the pre-tension state of the ball screws on both sides and the relative position of the two nut seats constant.

[0025] According to the above technical solution, a telescopic protective cover can also be detachably connected between the bed base and the worktable body. The telescopic protective cover is used to cover the guide mechanism and the feed drive system.

[0026] Compared with the prior art, the beneficial effects of the present invention, using the above technical solution, are as follows:

[0027] 1. This application achieves purely mechanical torque balance and dynamic correction of synchronization error between the two ball screws by setting two differential linkage elastic synchronizers in the feed drive system. Each synchronizer consists of a planetary differential gear train and an elastic balancing component. Specifically, when the loads on the two ball screws differ, the output sun gear speed on the side with the larger load tends to lag behind the input gear ring. The rotation of the double planetary gears drives the planet carrier to rotate against the bias force of the elastic element group. The rotation of the planet carrier causes the end face cam fixed on it to rotate relative to the roller follower. The roller climbs from the trough to the crest along the end face cam surface, and the paired high-stiffness disc spring group is further compressed, generating a larger restoring torque. This restoring torque acts on the double planetary gears through the planet carrier. The system applies an additional driving torque to the output sun gear to compensate for the load increase of the ball screw on that side. At the same time, the synchronizer on the side with the smaller load rotates in the opposite direction, and the disc spring group releases part of its elastic force, reducing the driving torque on the output sun gear on that side. Through the coordinated action of the synchronizers on both sides, the automatic balance distribution of torque between the two ball screws is achieved. When the off-center load is eliminated, the elastic force of the disc spring group drives the end face cam to drive the planetary carrier back to the zero angle position, and the system automatically resets. This not only achieves mechanical synchronization of dual-side drive, but also features fully passive, zero-delay, and maintenance-free adaptive characteristics. The entire dynamic correction process is completed autonomously by the mechanical structure without the participation of the electrical control system. The response speed is far superior to electronic servo solutions, and it is not affected by electromagnetic interference.

[0028] 2. This application utilizes a screw thermal expansion linkage compensation mechanism. This mechanism constructs the end bearing seat of the right ball screw as a floating bearing seat capable of axial sliding, and couples the fixed bearing seat of the left ball screw to the floating bearing seat via a mechanical compensation lever. The fulcrum of the mechanical compensation lever is located in the middle, used to transmit the displacement difference to the floating bearing seat according to a preset ratio when the left and right ball screws experience unequal thermal expansion, driving its axial sliding. This maintains the pre-tension state of the two ball screws and the relative position of the two nut seats, achieving linkage compensation for the thermal expansion of the two screws. The sliding amount of the floating bearing seat is exactly equal to the difference in thermal expansion of the two ball screws, achieving precise proportional compensation. Furthermore, it maintains the pre-tension state of the two ball screws, preventing the screw preload from becoming loose or excessive due to thermal expansion. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall structure of the present invention from the left side;

[0030] Figure 2 This is a schematic diagram of the overall structure of the present invention on the right side;

[0031] Figure 3 This is a cross-sectional view of the overall structure of the present invention;

[0032] Figure 4 This is a schematic diagram of the bed base structure connection of the present invention;

[0033] Figure 5 This is a schematic diagram of the feed drive system structure of the present invention;

[0034] Figure 6 This is a cross-sectional schematic diagram of the differential linkage elastic synchronizer structure of the present invention;

[0035] Figure 7 This is a schematic diagram of the planetary differential gear train structure of the present invention;

[0036] Figure 8 This is a schematic diagram showing the disassembled structure of the planetary differential gear train of the present invention;

[0037] Figure 9 This is a cross-sectional view of the shell structure of the present invention.

[0038] Figure 10 This is a cross-sectional front view of the shell structure of the present invention;

[0039] Figure 11 for Figure 10 Enlarged schematic diagram of the structure at point A in the middle;

[0040] Figure 12 This is a cross-sectional schematic diagram of the limiting pin structure of the present invention.

[0041] The following are the labeling instructions in the diagram: 10. Bed base; 20. Worktable body; 30. Guide mechanism; 31. First guide rail; 32. Second guide rail; 40. Feed drive system; 41. Servo motor; 42. T-type commutator; 43. Drive shaft; 44. Differential linkage elastic synchronizer; 45. Ball screw; 46. Nut seat; 47. Reducer; 50. Disc spring assembly; 51. Roller follower; 60. Viscous damping cavity; 70. Limit pin; 71. Threaded adjusting shaft; 72. Push rod; 80. Screw thermal expansion linkage compensation mechanism; 81. Floating bearing seat; 82. Mechanical compensation lever; 441. Housing; 442. Planetary differential gear train; 443. Elastic balance component; 444. Input gear ring; 445. Output sun gear; 446. Double planetary gears; 447. Planetary carrier; 448. End face cam; 449. Spring seat. Detailed Implementation

[0042] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. It should be noted that the description of these embodiments is for the purpose of helping to understand the present invention, but does not constitute a limitation of the present invention; in addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0043] In a preferred embodiment of the present invention, the curved profile of the end face cam 448 is constructed such that: at the zero angle position of the planetary carrier 447, the contact point between the roller follower 51 and the curved surface of the end face cam 448 is located at the trough of the curved surface, at which time the disc spring assembly 50 is in the initial compression state, and its circumferential restoring torque on the planetary carrier 447 is zero; when the planetary carrier 447 deviates from the zero angle position, the roller follower 51 moves along the curved surface of the end face cam 448 from the trough to the crest, and the compression of the disc spring assembly 50 increases with the increase of the deviation angle, and the generated circumferential restoring torque has a nonlinear positive correlation with the deviation angle;

[0044] Preferably, the curved profile of the end face cam 448 is designed with a cosine curve or a cycloidal curve, so that there is a preset stiffness characteristic curve between the reset torque and the deviation angle of the planetary carrier 447; by reasonably designing the combined stiffness of the curved profile of the end face cam 448 and the disc spring assembly 50, the differential linkage elastic synchronizer 44 can have linear or near-linear torque and angle characteristics within the rated load difference range (preferably 0 to 30% of the rated load), thereby achieving smooth compensation for the load difference of the ball screws 45 on both sides;

[0045] In a preferred embodiment of the present invention, the disc spring assembly 50 is composed of multiple disc springs arranged in pairs or stacked, and its combined stiffness is set according to the rated load of the ball screw 45 and the maximum allowable synchronization error. Preferably, the combined stiffness of the disc spring assembly 50 is configured such that when the torsion angle of the planetary carrier 447 reaches the maximum allowable elastic torsion angle (preferably ±3° to ±8°), the restoring torque generated by the disc spring assembly 50 is equal to 20% to 50% of the rated load torque of the ball screw 45. This parameter range ensures that the synchronizer has sufficient sensitivity for rapid response within the normal off-center load range, and avoids permanent deformation or damage caused by the elastic element exceeding its elastic limit under extreme off-center load conditions.

[0046] In a preferred embodiment of the present invention, the damping medium filled in the viscous damping cavity 60 is high-viscosity damping silicone oil. The viscous damping cavity 60 is formed by the outer peripheral surface of the end face cam 448 and the inner wall of the housing 441 to form an annular sealed chamber. The outer peripheral surface of the end face cam 448 is provided with an annular damping groove or damping blade to increase the contact area between the damping medium and the end face cam 448 and improve the damping effect. By setting the viscous damping cavity 60, when the end face cam 448 rotates with the planetary carrier 447, the damping medium generates viscous shear resistance, which converts the vibration energy of the planetary carrier 447 during rotation into heat energy consumption, effectively suppressing the oscillation of the system and improving the stability of the synchronous adjustment process.

[0047] Preferably, the damping coefficient of the viscous damping cavity 60 is configured to be 5% to 20% of the equivalent stiffness of the disc spring assembly 50, so as to achieve critical damping or underdamping control of the dynamic response of the system, so that the system can quickly converge to the equilibrium state without significant overshoot or oscillation after being subjected to a step load.

[0048] As a preferred embodiment of the present invention, the end of the threaded adjusting shaft 71 of the limiting pin 70 extending out of the outer side of the housing 441 is provided with an adjusting scale or a locking nut. The operator can adjust the length of the threaded adjusting shaft 71 extending into the inner cavity of the housing 441 by rotating the threaded adjusting shaft 71, thereby adjusting the maximum allowable torsion angle of the planetary carrier 447.

[0049] Preferably, the maximum permissible elastic torsion angle of the planetary carrier 447 is set to ±5° to ±10°; a wear-resistant pad or rolling element is provided at the end of the push rod 72 that contacts the planetary carrier 447 to reduce contact friction; the stiffness of the elastic element in the push rod 72 is less than the combined stiffness of the disc spring assembly 50, preferably 10% to 30% of the combined stiffness of the disc spring assembly 50, so that the push rod 72 only provides auxiliary restoring force when the planetary carrier 447 approaches the maximum permissible torsion angle, without interfering with the free rotation of the planetary carrier 447 within the normal off-center load range.

[0050] like Figures 1 to 5 As shown, the present invention provides a double-feed horizontal worktable, including a bed base 10, a worktable body 20, a guide mechanism 30, and a feed drive system 40; wherein, the bed base 10 serves as the mounting base for the entire worktable, and is integrally cast from high-strength cast iron material, possessing good rigidity and vibration damping performance; the worktable body 20 is disposed above the bed base 10 and is used to support the workpiece to be processed;

[0051] Specifically, the guiding mechanism 30 includes a first guide rail 31 and a second guide rail 32, which are respectively fixed on both sides of the bed base 10 and extend in parallel. Both the first guide rail 31 and the second guide rail 32 are high-precision linear rolling guide rails and are fixedly installed on both sides of the upper surface of the bed base 10 by bolt assemblies. The bottom sides of the worktable body 20 are slidably engaged with the first guide rail 31 and the second guide rail 32. Specifically, sliders adapted to the first guide rail 31 and the second guide rail 32 are fixedly provided on the bottom sides of the worktable body 20. The sliders slide back and forth along the length of the guide rails, thereby realizing the feed movement of the worktable body 20. By setting the first guide rail 31 and the second guide rail 32 on both sides of the bed base 10, the support span of the worktable body 20 is maximized, effectively resisting the off-center load torque and improving the stability and guiding accuracy of the worktable movement.

[0052] like Figures 3 to 5As shown, the feed drive system 40 includes a servo motor 41, a T-type commutator 42, two parallel drive shafts 43, two differential linkage elastic synchronizers 44, two ball screws 45, and a nut seat 46 that is threadedly adapted to the ball screws 45. The servo motor 41 is a high-response AC servo motor, and its output end is driven to the input end of the T-type commutator 42 via a reducer 47. The reducer 47 is preferably a planetary gear reducer, which is used to convert the high-speed, low-torque output of the servo motor 41 into a low-speed, high-torque output to meet the high torque requirements of the table feed drive.

[0053] Specifically, the two output ends of the T-type commutator 42 are coaxially and fixedly connected to one end of each of the two drive shafts 43. The T-type commutator 42 is a spiral bevel gear commutator, in which the internal bevel gear pair distributes the input torque of the servo motor 41 to the two parallel drive shafts 43 at the same speed and in the same direction through rigid meshing. Specifically, the T-type commutator 42 has one input bevel gear and two output bevel gears, which mesh simultaneously with the two output bevel gears. The axes of the two output bevel gears are parallel and have the same direction of rotation, thereby realizing the conversion of a single input rotational motion into two rotational outputs in the same direction and at the same speed. Compared with the electronic synchronization method, this rigid mechanical transmission distribution method has the advantages of no response delay, strong anti-interference ability, and high synchronization accuracy.

[0054] The other ends of the two drive shafts 43 are coaxially and fixedly connected to the input ends of the two differential linkage elastic synchronizers 44 respectively; the output ends of the two differential linkage elastic synchronizers 44 are coaxially and fixedly connected to the shaft ends of the two ball screws 45 respectively; the drive shafts 43 are made of high-strength alloy steel, and their two ends are respectively connected to the output ends of the coupling and the T-type commutator 42 and the input ends of the differential linkage elastic synchronizers 44 through bevel gear sets; the ball screws 45 are high-precision ground ball screws, and their two ends are rotatably supported on the bed base 10 through bearing seats;

[0055] Two nut seats 46 are fixedly installed on the bottom sides of the worktable body 20, and are respectively threaded to the corresponding ball screws 45. When the ball screws 45 rotate, the nut seats 46 move along the axis of the ball screws 45, thereby driving the worktable body 20 to slide along the first guide rail 31 and the second guide rail 32.

[0056] like Figures 6 to 11 As shown, the differential linkage elastic synchronizer 44 includes a housing 441 and a planetary differential gear train 442 and an elastic balance assembly 443 disposed inside the housing 441.

[0057] The housing 441 is a modular box structure and is fixedly installed on the bed base 10 by bolts. Its interior forms a cavity for accommodating the planetary differential gear train 442 and the elastic balancing component 443. One end of the housing 441 is provided with an input hole for the drive shaft 43 to pass through, and the other end is provided with an output hole for the ball screw 45 to pass through. Rotary seals and support bearings are respectively provided in the input hole and the output hole.

[0058] The planetary differential gear train 442 includes an input gear ring 444, an output sun gear 445, a double planetary gear 446, and a planet carrier 447. The input gear ring 444 forms the input end of the differential linkage elastic synchronizer 44 and is coaxially fixed to the corresponding drive shaft 43. Specifically, the inner circumferential surface of the input gear ring 444 is provided with internal teeth, and it is coaxially fixed to the end of the drive shaft 43 by key connection or spline connection. The output sun gear 445 forms the output end of the differential linkage elastic synchronizer 44 and is coaxially fixed to the corresponding ball screw 45. Specifically, the output sun gear... The outer circumferential surface of 445 is provided with external teeth, which are coaxially fixed to the shaft end of the ball screw 45 by means of key connection or spline connection; the double planetary gear 446 consists of two coaxially arranged gears that simultaneously mesh with the internal teeth of the input gear ring 444 and the external teeth of the output sun gear 445; the planet carrier 447 is rotatably supported in the housing 441, and the double planetary gear 446 is rotatably mounted on the planet carrier 447; the planet carrier 447 is supported on the inner wall of the housing 441 by bearings, so that the planet carrier 447 can rotate at a certain angle relative to the housing 441;

[0059] The elastic balancing assembly 443 includes an end face cam 448 fixed on the planetary carrier 447, a spring seat 449 fixed on the housing 441, and an elastic element group compressed between the spring seat 449 and the end face cam 448. The end face cam 448 is fixedly mounted on the end face of the planetary carrier 447, and has an undulating cam surface on the side facing the spring seat 449. The spring seat 449 is fixedly mounted on the inner wall of the housing 441, located on the axial side of the end face cam 448. The elastic element group is configured to apply an axial biasing force to the end face cam 448 to force the planetary carrier 447 to remain at the zero angle position in the free state.

[0060] like Figure 6 and Figure 11As shown, the elastic element group consists of a pair of high-stiffness disc spring groups 50, which maintain contact with the curved surface of the end face cam 448 through the roller follower 51, so as to convert the axial elastic force of the disc spring group 50 into a circumferential restoring torque on the planet carrier 447. Specifically, the disc spring group 50 is composed of multiple disc springs that are paired or stacked, and is disposed between the spring seat 449 and the roller follower 51. One end of the roller follower 51 abuts against the disc spring group 50, and the other end is provided with a roller, which makes rolling contact with the cam surface of the end face cam 448. When the planet carrier 447 is at the zero angle position, the roller is located at the trough position of the curved surface of the end face cam 448, the compression of the disc spring group 50 is the maximum, and the generated axial force is transmitted through the roller from the end face cam 448 to the end face cam 448. The actuator 51 acts on the curved surface of the end face cam 448. Since the tangential component of the curved surface is zero at the trough, the planet carrier 447 remains balanced at this position. When the planet carrier 447 deviates from the zero angle position, the rollers climb up the curved surface of the end face cam 448 to the crest position, and the disc spring assembly 50 is further compressed. Its axial elastic force generates a tangential component on the cam curved surface. This tangential component forms a circumferential restoring torque on the planet carrier 447, driving the planet carrier 447 back to the zero angle position. The curved surface profile of the end face cam 448 and the stiffness of the disc spring assembly 50 are set according to actual needs, so as to obtain the required restoring torque characteristics by reasonably designing the curved surface profile of the end face cam 448 and the stiffness of the disc spring assembly 50.

[0061] like Figure 9 and Figure 10 As shown, a viscous damping cavity 60 is also provided between the end face cam 448 and the housing 441. The viscous damping cavity 60 is filled with a damping medium to absorb the vibration energy during the offset process of the end face cam 448. Specifically, the viscous damping cavity 60 is an annular sealed chamber formed by the outer peripheral surface of the end face cam 448 and the inner wall of the housing 441, and is filled with high-viscosity damping silicone oil. When the end face cam 448 rotates with the planetary carrier 447, the damping medium in the viscous damping cavity 60 generates viscous shear resistance, thereby consuming the vibration energy during the offset process of the end face cam 448, suppressing the oscillation of the system, and improving the stability of synchronous adjustment.

[0062] like Figures 9 to 12 As shown, a limiting pin 70 fixed to the housing 441 is also provided on the rotation path of the planet carrier 447 to limit the maximum elastic torsion angle of the planet carrier 447. The limiting pin 70 passes through the wall of the housing 441 radially, and its inner end extends into the inner cavity of the housing 441 and is located on the rotation path of the planet carrier 447. When the planet carrier 447 rotates to the maximum allowable angle, the corresponding part of the planet carrier 447 abuts against the inner end of the limiting pin 70, thereby limiting the planet carrier 447 from continuing to rotate and preventing damage to the planetary differential gear train 442 or the elastic element group from exceeding the elastic limit due to excessive torsion.

[0063] like Figure 12 As shown, the limiting pin 70 includes a threaded adjusting shaft 71 threadedly connected to the housing 441 and a push rod 72 slidably disposed within the threaded adjusting shaft 71 via an elastic element. The threaded adjusting shaft 71 has an external thread on its outer periphery, which threadly engages with a threaded hole on the housing 441. By rotating the threaded adjusting shaft 71, its length extending into the inner cavity of the housing 441 can be adjusted, thereby adjusting the maximum permissible torsion angle of the planetary carrier 447. The push rod 72 is slidably disposed within the axial hole of the threaded adjusting shaft 71. An elastic element (preferably a compression spring) is disposed between the bottom of the axial hole and the push rod 72, applying an outward elastic force to the push rod 72. The push rod 72 is within the elastic element... Under the action of the elastic element, it elastically abuts against the planetary carrier 447, providing auxiliary elastic reset constraint for the rotating planetary carrier 447 and buffering the impact of the planetary carrier 447 on the limit pin 70. When the planetary carrier 447 rotates to contact the push rod 72, the push rod 72 slides into the threaded adjusting shaft 71 under the push of the planetary carrier 447, overcoming the elastic force of the elastic element. The reaction force of the elastic element acts on the planetary carrier 447 through the push rod 72, forming an auxiliary reset torque. At the same time, the setting of the elastic element makes the planetary carrier 447 and the limit pin 70 form an elastic contact rather than a rigid collision, effectively buffering the impact force and protecting the components of the planetary differential gear train 442.

[0064] When the loads on the two ball screws 45 differ, the planetary carrier 447 of the corresponding differential linkage elastic synchronizer 44 can overcome the bias force of the elastic element group and rotate. Through the absorption and compensation of the planetary differential gear train 442, the torque balance of the two ball screws 45 and the dynamic correction of the synchronization error are realized.

[0065] Specifically, under normal operating conditions, the loads on the two ball screws 45 are equal, the planet carriers 447 of the two differential linkage elastic synchronizers 44 are both at the zero angle position, the input gear ring 444 and the output sun gear 445 transmit torque through the double planetary gears 446 with a fixed transmission ratio, the two ball screws 45 rotate synchronously, and the worktable body 20 is fed smoothly.

[0066] When the worktable body 20 is subjected to an off-center load, such as when the center of gravity of the workpiece shifts, causing the load on one side to increase and the load on the other side to decrease, a difference in load will occur between the two ball screws 45. The ball screw 45 on the side with a larger load will bear a greater resistance torque. The rotational speed of the output sun gear 445 of the differential linkage elastic synchronizer 44 on this side will lag behind the input gear ring 444. The double planetary gear 446 will generate a rotational motion on this side, driving the planetary carrier 447 to rotate against the biasing force of the elastic element group. The rotation of the planetary carrier 447 will cause the end face cam 448 to rotate relative to the roller follower 51. The roller moves along the curved surface of the end face cam 448 from the trough. As the disc spring assembly climbs towards the crest, it is further compressed, generating a larger restoring torque. This restoring torque acts on the double planetary gears 446 through the planet carrier 447, applying an additional driving torque to the output sun gear 445 to compensate for the load increase of the ball screw 45 on that side. At the same time, the planet carrier 447 of the differential linkage elastic synchronizer 44 on the side with the smaller load rotates in the opposite direction, and the disc spring assembly 50 releases part of its elastic force, reducing the driving torque on the output sun gear 445 on that side. Through the synergistic effect of the differential linkage elastic synchronizers 44 on both sides, the automatic torque balance distribution between the two ball screws 45 is achieved.

[0067] When the off-center load is eliminated, the load on both sides of the ball screw 45 is restored to balance, and the elastic force of the disc spring group 50 drives the end face cam 448 to drive the planetary carrier 447 back to the zero angle position, and the system automatically resets; the entire dynamic correction process is completed entirely by the self-adaptation of the mechanical structure without the participation of the electrical control system, and the response speed is fast and the reliability is high.

[0068] The nut seat 46 is a double-nut structure. When wear gaps occur between the ball screw 45 and the nut seat 46, the double-nut nut seat 46 is configured to automatically fit against the thread surface of the ball screw 45 to achieve symmetrical preload on both sides of the thread groove of the ball screw 45. Specifically, the nut seat 46 includes two half-nuts and a preload adjustment member disposed between the two half-nuts. The two half-nuts respectively cooperate with the two sides of the thread groove of the ball screw 45. The preload adjustment member (preferably a disc spring or a threaded adjustment sleeve) applies an axial preload force to the two half-nuts, so that the two half-nuts respectively fit against the two sides of the thread groove of the ball screw 45. When wear gaps occur between the ball screw 45 and the nut seat 46 due to long-term use, the preload adjustment member automatically compensates for the gaps, maintaining close contact between the two half-nuts and the two sides of the thread groove of the ball screw 45, thereby eliminating backlash and improving the transmission accuracy and rigidity of the feed system.

[0069] like Figure 3 and Figure 4As shown, the horizontal worktable also includes a lead screw thermal expansion linkage compensation mechanism 80; the lead screw thermal expansion linkage compensation mechanism 80 constructs the end bearing seat of the ball screw 45 located on the right side as a floating bearing seat 81 that can slide along the axial direction, and couples the fixed bearing seat of the ball screw 45 located on the left side with the floating bearing seat 81 through a mechanical compensation lever 82.

[0070] Specifically, the two ends of the left ball screw 45 are rotatably supported on the bed base 10 by fixed bearing seats. The fixed bearing seats are made of angular contact ball bearings installed back to back, which can withstand bidirectional axial loads and fix the axial position of the left ball screw 45. One end of the right ball screw 45 is supported by a fixed bearing seat, and the other end is supported by a floating bearing seat 81. The floating bearing seat 81 is slidably disposed on a slide rail provided on the bed base 10 and can slide freely along the axial direction of the ball screw 45. A thrust bearing is provided in the floating bearing seat 81 to bear the axial force of the right ball screw 45 and allow the ball screw 45 to rotate.

[0071] The fulcrum of the mechanical compensation lever 82 is located in the middle. When the ball screws 45 on the left and right sides produce unequal thermal elongation, the displacement difference is transmitted to the floating bearing seat 81 according to a preset ratio to drive the floating bearing seat 81 to slide axially, thereby maintaining the pre-tension state of the ball screws 45 on both sides and the relative position of the two nut seats 46.

[0072] Specifically, the mechanical compensating lever 82 is a rigid rod, the middle of which is rotatably supported on the bed base 10 via a hinge shaft, forming a lever fulcrum; one end of the mechanical compensating lever 82 is connected to the fixed bearing seat (or a transmission component fixedly connected to the fixed bearing seat) of the left ball screw 45, and the other end is connected to the floating bearing seat 81; when the left and right ball screws 45 undergo unequal thermal expansion due to temperature rise, the thermal expansion of the left ball screw 45 is transmitted to one end of the mechanical compensating lever 82 through the fixed bearing seat, driving the lever to rotate around the fulcrum, and the other end of the lever displaces the lever. The lever ratio is transmitted to the floating bearing seat 81, driving the floating bearing seat 81 to slide a corresponding distance along the axial direction, thereby compensating for the thermal expansion of the right ball screw 45. By reasonably setting the fulcrum position of the lever (i.e., the lever ratio), the sliding amount of the floating bearing seat 81 can be exactly equal to the difference in thermal expansion of the two ball screws 45, thereby maintaining the relative position of the two nut seats 46 constant and ensuring that the feed accuracy of the worktable body 20 is not affected by thermal deformation. At the same time, the mechanism can also maintain the pre-tension state of the two ball screws 45, avoiding the loosening or excessive preload of the screw due to thermal expansion.

[0073] Furthermore, a telescopic protective cover is detachably connected between the bed base 10 and the worktable body 20. The telescopic protective cover is used to cover the guide mechanism 30 and the feed drive system 40. One end of the telescopic protective cover is fixed to the bed base 10, and the other end is fixed to the bottom of the worktable body 20. It extends and retracts with the feed movement of the worktable body 20. The telescopic protective cover isolates precision components such as the first guide rail 31, the second guide rail 32, and the ball screw 45 from the external environment, preventing cutting fluid, chips, dust, and other debris from entering, extending the service life of the guide mechanism and the feed drive system, and ensuring transmission accuracy.

[0074] The overall working principle of this invention:

[0075] First, the servo motor 41 is started. The output torque of the servo motor 41 is reduced and amplified by the reducer 47 and then transmitted to the input end of the T-type commutator 42. The T-type commutator 42 distributes the input torque at the same speed and in the same direction to two parallel drive shafts 43 through its internal spiral bevel gear pair. The two drive shafts 43 transmit the torque to the input ends (i.e., input gear rings 444) of two differential linkage elastic synchronizers 44 respectively.

[0076] Under normal operating conditions, the loads on the two ball screws 45 are equal, and the planetary carriers 447 of the two differential linkage elastic synchronizers 44 are both at the zero angle position; the input gear ring 444 drives the output sun gear 445 to rotate through the double planetary gears 446, and the output sun gear 445 drives the corresponding ball screw 45 to rotate; the two ball screws 45 rotate synchronously, driving the two nut seats 46 to move synchronously, and driving the worktable body 20 to reciprocate smoothly along the first guide rail 31 and the second guide rail 32.

[0077] When the worktable body 20 is subjected to an off-center load, the loads on the two ball screws 45 differ. This load difference causes the planetary carrier 447 of the differential linkage elastic synchronizer 44 on the corresponding side to rotate, overcoming the off-center force of the disc spring assembly 50. The rotation of the planetary carrier 447, through the absorption and compensation of the planetary differential gear train 442, automatically adjusts the output torque of the output sun gears 445 on both sides, making the torques of the ball screws 45 on both sides tend to be balanced. At the same time, the damping medium in the viscous damping cavity 60 absorbs the vibration energy during the offset process of the end face cam 448, ensuring a smooth and oscillating adjustment process. The limit pin 70 limits the maximum elastic torsion angle of the planetary carrier 447 to prevent excessive torsion. When the off-center load is eliminated, the disc spring assembly 50 drives the end face cam 448 to move the planetary carrier 447 back to the zero angle position, and the system automatically resets.

[0078] Throughout the entire operation, the lead screw thermal elongation linkage compensation mechanism 80 monitors and compensates for the unequal thermal elongation of the ball screws 45 on both sides due to temperature rise in real time, maintaining the pre-tension state of the ball screws 45 on both sides and the constant relative position of the two nut seats 46; the nut seat 46 with double nut structure automatically compensates for the wear gap between the ball screw 45 and the nut seat 46, maintaining high-precision transmission without backlash.

[0079] In the description of this invention, it should be understood that the terms "center", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this 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. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0080] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the foregoing; the descriptions above and in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A double-feed horizontal worktable, characterized in that, The system includes a bed base (10), a worktable body (20), a guide mechanism (30), and a feed drive system (40), characterized in that: The guiding mechanism (30) includes a first guide rail (31) and a second guide rail (32) that are fixed on both sides of the bed base (10) and extend in parallel. The bottom sides of the worktable body (20) are slidably engaged with the first guide rail (31) and the second guide rail (32) respectively. The feed drive system (40) includes a servo motor (41), a T-type commutator (42), two parallel drive shafts (43), two differential linkage elastic synchronizers (44), two ball screws (45), and a nut seat (46) adapted to the thread of the ball screws (45). The servo motor (41) is driven to the input end of the T-type commutator (42) via a reducer (47); The two output ends of the T-type commutator (42) are respectively coaxially and fixedly connected to one end of the two drive shafts (43); The other ends of the two drive shafts (43) are respectively coaxially and fixedly connected to the input ends of the two differential linkage elastic synchronizers (44); The output ends of the two differential linkage elastic synchronizers (44) are respectively coaxially and fixedly connected to the shaft ends of the two ball screws (45); The differential linkage elastic synchronizer (44) includes a housing (441) and a planetary differential gear train (442) and an elastic balance assembly (443) disposed inside the housing (441). The planetary differential gear train (442) includes an input gear ring (444), an output sun gear (445), a double planetary gear (446), and a planet carrier (447). The input gear ring (444) forms the input end and is coaxially fixed with the corresponding drive shaft (43). The output sun gear (445) forms the output end and is coaxially fixed with the corresponding ball screw (45). The planet carrier (447) is rotatably supported in the housing (441). The elastic balancing assembly (443) includes an end face cam (448) fixed on the planet carrier (447), a spring seat (449) fixed on the housing (441), and an elastic element group compressed between the spring seat (449) and the end face cam (448). The elastic element group is configured to apply an axial biasing force to the end face cam (448) to force the planet carrier (447) to remain at the zero angle position in a free state. When the loads of the two ball screws (45) differ, the planetary carrier (447) of the corresponding differential linkage elastic synchronizer (44) can overcome the bias pressure of the elastic element group and rotate. Through the absorption and compensation of the planetary differential gear train (442), the torque balance of the two ball screws (45) and the dynamic correction of the synchronization error are realized.

2. A double-feed horizontal worktable according to claim 1, characterized in that: The elastic element group is a pair of high-stiffness disc spring groups (50), which are kept in contact with the curved surface of the end face cam (448) through a roller follower (51) to convert the axial elastic force of the disc spring group (50) into a circumferential restoring torque on the planet carrier (447).

3. A double-feed horizontal worktable according to claim 2, characterized in that: A viscous damping cavity (60) is provided between the end face cam (448) and the housing (441). The viscous damping cavity (60) is filled with a damping medium to absorb the vibration energy during the offset process of the end face cam (448).

4. A double-feed horizontal worktable according to claim 3, characterized in that: The planetary carrier (447) is also provided with a limiting pin (70) fixed to the housing (441) on its rotation path to limit the maximum elastic torsion angle of the planetary carrier (447).

5. A double-feed horizontal worktable according to claim 4, characterized in that: The limiting pin (70) includes a threaded adjusting shaft (71) threadedly connected to the housing (441) and a push rod (72) slidably disposed in the threaded adjusting shaft (71) by an elastic element. The push rod (72) elastically abuts against the planetary carrier (447) under the action of the elastic element, and is used to provide auxiliary elastic reset constraint for the planetary carrier (447) in the rotating state, and to buffer the impact of the planetary carrier (447) on the limiting pin (70).

6. A double-feed horizontal worktable according to claim 1, characterized in that: The T-type commutator (42) is a spiral bevel gear commutator, in which the internal bevel gear pair distributes the input torque of the servo motor (41) to the two parallel drive shafts (43) in a rigid meshing manner at the same speed and in the same direction.

7. A double-feed horizontal worktable according to any one of claims 1 to 4, characterized in that: The nut seat (46) is a double nut structure. When a wear gap occurs between the ball screw (45) and the nut seat (46), the nut seat (46) with the double nut structure is configured to automatically fit against the thread surface of the ball screw (45) to achieve symmetrical pre-tightening on both sides of the thread groove of the ball screw (45).

8. The double-feed horizontal worktable according to any one of claims 1 to 4, characterized in that: The horizontal worktable also includes a lead screw thermal expansion linkage compensation mechanism (80), which constructs the end bearing seat of the ball screw (45) on the right side as a floating bearing seat (81) that can slide along the axial direction, and couples the fixed bearing seat of the ball screw (45) on the left side with the floating bearing seat (81) through a mechanical compensation lever (82).

9. A double-feed horizontal worktable according to claim 8, characterized in that: The fulcrum of the mechanical compensation lever (82) is located in the middle, and is used to transmit the displacement difference to the floating bearing seat (81) according to a preset ratio when the ball screws (45) on the left and right sides generate unequal thermal elongation, so as to drive the floating bearing seat (81) to slide axially, thereby maintaining the pre-tension state of the ball screws (45) on both sides and the relative position of the two nut seats (46) constant.

10. A double-feed horizontal worktable according to claim 1, characterized in that: A telescopic protective cover is detachably connected between the bed base (10) and the worktable body (20), the telescopic protective cover being used to cover the guide mechanism (30) and the feed drive system (40).

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