High-precision direct-drive type turning and milling worktable

Abstract

This invention provides a high-precision direct-drive milling and turning worktable, comprising a worktable, a base, a direct-drive torque motor, crossed roller bearings, and a circular grating assembly. The worktable is connected to the rotor of the direct-drive torque motor via a transition plate. A sleeve is fixed on the base, and the stator of the direct-drive torque motor is fixed to the sleeve. The outer circumference of the sleeve has inlet / outlet water holes, which communicate with an annular water groove on the outer circumference of the stator of the direct-drive torque motor to form a first cooling channel. The rotor of the direct-drive torque motor is embedded in the positioning stop of the transition plate and fixed. An inner sleeve is provided between the rotor of the direct-drive torque motor and the base, and the rotor of the direct-drive torque motor has relative movement with the inner sleeve. The end face of the inner sleeve has cooling water holes, which communicate with an annular groove on the base to form a second cooling channel. This invention's milling and turning worktable features a thermally symmetrical structure, high dynamic and static rigidity, high rotational accuracy of the worktable base, good accuracy retention, large load capacity, high speed, and good manufacturability, and can significantly reduce machine tool costs.

Description

Technical Field

[0001] This invention relates to the field of machine tool technology, and specifically to a high-precision direct-drive milling and turning table. Background Technology

[0002] Vertical milling and turning machines are the basic equipment for flexible and agile manufacturing systems. Their general development trend is: high speed, high precision, high efficiency, intelligence and integration, while emphasizing process applicability and economy.

[0003] In recent years, with the vigorous development of China's equipment manufacturing industry, the machine tool industry, as the mother machine of the equipment manufacturing industry, has become more prominent. In order to meet the needs of various industrial enterprises, machine tool manufacturers have launched high-precision machine tools, especially high-precision machine tools with turning and milling tables.

[0004] Taking a vertical milling and turning machine as an example, the rotary spindle of the worktable is the core part of the vertical milling and turning machine. The rotational accuracy of the spindle will directly affect the roundness, cylindricity, runout and other accuracy of the machined parts. The spindle structure adopted by the machine tool will affect the rotational diameter of the machine tool and the load-bearing capacity of the worktable.

[0005] In existing technology, the spindle of a vertical milling turner's worktable is generally constructed using a combination of two thrust ball bearings (one large and one small) and a double-row cylindrical roller bearing. This structure is quite typical, where the large thrust ball bearing bears the axial force of the worktable, the small thrust ball bearing provides preload, and the double-row cylindrical roller bearing bears the radial force of the worktable.

[0006] However, this structure also has certain drawbacks. The versatility of thrust ball bearings is poor for machine tools of different specifications. That is, a thrust ball bearing of a certain specification can only be used for machine tools of the corresponding specification. This is because the load-bearing capacity and limiting speed of thrust ball bearings are limited. For example, if a larger thrust ball bearing is used on a smaller machine tool, the load-bearing capacity can be met, but the speed cannot be met. If a smaller thrust ball bearing is used on a larger machine tool, the speed can be met, but the load-bearing capacity cannot be met.

[0007] In addition, the installation process of double-row cylindrical roller bearings is relatively complex, making it difficult to guarantee the end face runout accuracy, and they are difficult to repair after wear, which will consequently affect the machining accuracy of the workpiece. Summary of the Invention

[0008] The purpose of this invention is to address the shortcomings of existing technologies by providing a high-precision direct-drive milling and turning table.

[0009] The specific technical solution is as follows:

[0010] A high-precision direct-drive milling and turning worktable includes: a worktable, a base, a direct-drive torque motor, crossed roller bearings, and a circular grating assembly;

[0011] The workbench is connected to the rotor of the direct drive torque motor via a transition plate. A sleeve is fixed on the base. The stator of the direct drive torque motor is fixed to the sleeve. The outer circle of the sleeve is provided with water inlet / outlet holes, which communicate with the annular water groove provided on the outer circle of the stator to form a first cooling channel. The rotor is embedded in the positioning stop of the transition plate and fixed. An inner sleeve is provided between the rotor and the base. The rotor and the inner sleeve have relative movement. The end face of the inner sleeve is provided with cooling water holes, which communicate with the annular groove provided on the base to form a second cooling channel.

[0012] The crossed roller bearing includes an outer ring and an inner ring, both of which are integral structures; its outer ring is fixed to the bottom of the inner hole of the transition plate, and its inner ring is installed on the spindle shoulder and clamped by a lower pressure plate and an upper pressure plate. A grindable adjusting shim is provided between the upper pressure plate and the inner ring.

[0013] The circular grating assembly includes a circular grating, an encoder, a connecting shaft, a flange, a sealing flange, and an adjusting shim. The flange is fixed to the center hole of the worktable. The connecting shaft is connected to the flange through a transition plate and assembled with the circular grating and encoder through the adjusting shim. The sealing flange seals the center hole of the worktable to prevent coolant from seeping in.

[0014] Optionally, the rolling elements of the crossed roller bearing are tapered rollers or cylindrical rollers, with adjacent rollers arranged at 90° angles.

[0015] Optionally, the cage of the crossed roller bearing is a separate structure made of brass.

[0016] Optionally, the upper part of the sleeve is provided with a stop, and the cover is pressed into the stop to fix the stator of the direct drive torque motor.

[0017] Optionally, the inner sleeve is fixed to the base, and the cooling water hole on its end face forms a coolant circulation loop with the annular groove of the base.

[0018] Optionally, the circular grating assembly further includes a support sleeve and a support. The support sleeve is mounted on the main shaft, and the support is fixed to the support sleeve. The encoder housing is connected to the support by screws. The encoder coupling meshes with the small shaft at the end of the connecting shaft. The circular grating housing is positioned and connected to the support by a positioning stop.

[0019] Optionally, the outer ring of the crossed roller bearing is fixed to the bottom of the inner hole of the transition plate by a lower pressure plate, and the inner ring is fixed to the spindle shoulder by an upper pressure plate and an adjusting shim. The thickness of the grinding adjusting shim is matched to the axial preload by grinding.

[0020] Optionally, the worktable and the transition plate are connected by screws and pins, and the transition plate rotates synchronously with the rotor of the direct drive torque motor, driving the worktable, flange, and connecting shaft to achieve dual-mode drive control.

[0021] Optionally, the cooling water holes of the annular water tank of the stator and the annular water tank of the base of the direct drive torque motor are both designed with spiral flow channels, and the coolant flows in opposite directions. The water inlet of the sleeve is located at the lower end of its outer circle, and the water outlet is located at the upper end of its outer circle. The water inlet of the inner sleeve is located on the outer side of the end face, and the water outlet is located on the inner side of the end face, so as to form a convection heat dissipation structure for the inner and outer rings of the direct drive torque motor and improve the cooling efficiency.

[0022] A machine tool includes the high-precision direct-drive milling and turning worktable described above, wherein the machine tool is a vertical milling and turning machine, a vertical grinding machine, or a vertical milling and turning composite machine tool.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] This invention utilizes a direct-drive torque motor to directly drive the worktable, resulting in a simple structure, no backlash, smooth operation, and excellent low-speed characteristics. It also eliminates the high losses associated with transmission, achieving precise indexing and providing excellent worktable stability and high accuracy. Furthermore, the cross roller bearings employed feature high speed and large load capacity, capable of withstanding axial, radial, and overturning torques from external loads. The milling and turning worktable of this invention features a thermally symmetrical structure, high dynamic and static rigidity, high rotational accuracy of the worktable base, good accuracy retention, large load capacity, high speed, and good manufacturability, while significantly reducing machine tool costs. Attached Figure Description

[0025] Figure 1 A schematic diagram of the working structure of a high-precision direct-drive milling and turning table provided by the present invention;

[0026] Figure 2 for Figure 1 Enlarged structural diagram of the letter A in the middle.

[0027] In the diagram: 1. Worktable; 2. Base; 3. Direct drive torque motor; 4. Crossed roller bearing; 5. Sleeve; 6. Lower pressure plate; 7. Inner sleeve; 8. Spindle; 9. Cover; 10. Transition plate; 11. Upper pressure plate; 12. Grindable adjusting shim; 13. Sealing flange; 14. Transition plate; 15. Flange; 16. Adjusting shim; 17. Connecting shaft; 18. Support; 19. Support sleeve. Detailed Implementation

[0028] 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 embodiments of the present invention, and not all embodiments. 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.

[0029] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0030] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0031] The present invention provides a high-precision direct-drive milling and turning table, with reference to... Figures 1-2 ,include:

[0032] Worktable 1, base 2, direct drive torque motor 3, crossed roller bearing 4, and circular grating assembly;

[0033] The workbench 1 is connected to the rotor of the direct drive torque motor 3 via the transition plate 10. A sleeve 5 is fixed on the base 2. The stator of the direct drive torque motor 3 is fixed to the sleeve 5 by screws and pins. The outer circle of the sleeve 5 is provided with water inlet / outlet holes, which are connected to the annular water groove on the outer circle of the stator of the direct drive torque motor 3 to form a first cooling channel. The rotor of the direct drive torque motor 3 is embedded in the positioning stop of the transition plate 10 and fixed by screws and pins. An inner sleeve 7 is provided between the rotor of the direct drive torque motor 3 and the base 2. The rotor and the inner sleeve 7 have relative movement. The end face of the inner sleeve 7 is provided with cooling water holes, which are connected to the annular groove of the base 2 to form a second cooling channel.

[0034] The crossed roller bearing 4 includes an outer ring and an inner ring, both of which are integral structures. Its outer ring is fixed to the bottom of the inner hole of the transition plate 10 by an interference fit, and its inner ring is installed on the shoulder of the main shaft 8 by an interference fit and is clamped by the lower pressure plate 6 and the upper pressure plate 11. A grindable adjusting shim 12 is provided between the upper pressure plate 11 and the inner ring.

[0035] The circular grating assembly includes a circular grating, an encoder, a connecting shaft 17, a flange 15, a sealing flange 13, and an adjusting shim 16. The flange 15 is fixed to the center hole of the worktable 1. The connecting shaft 17 is connected to the flange 15 through a transition plate 14 and is precisely assembled with the circular grating and the encoder through the adjusting shim 16. The sealing flange 13 seals the center hole of the worktable 1 with an O-ring to prevent coolant from seeping in.

[0036] The direct-drive torque motor 3 drives the transition plate 10 to rotate the worktable 1. In the turning state, constant speed cutting and thread processing are achieved through the encoder. In the milling state, the position is detected by the circular grating in a closed loop.

[0037] Specifically, in this embodiment, in terms of cooling, the outer circle of sleeve 5 is provided with water inlet / outlet holes, which are connected to the annular water tank on the outer circle of the stator of the direct drive torque motor 3 to form a first cooling channel. The coolant provided by the water chiller enters the annular water tank on the outer circle of the stator of the direct drive torque motor 3 through the water inlet / outlet holes on the outer circle of sleeve 5, and cools its stator when the direct drive torque motor 3 is working, effectively removing the heat generated by the motor and preventing the motor from being affected or damaged due to overheating.

[0038] The rotor of the direct drive torque motor 3 is embedded in the positioning stop of the transition plate 10 and fixed with screws and pins. The connection between the rotor and the transition plate 10, secured by screws and pins, ensures that the rotor of the direct drive torque motor 3 can be stably connected to the worktable 1, thereby effectively driving the worktable 1 to rotate when the motor is driven. An inner sleeve 7 is provided between the rotor of the direct drive torque motor 3 and the base 2. The rotor and the inner sleeve 7 have relative movement. The inner sleeve 7 plays an auxiliary cooling role and also provides a structural basis for the cooling system. The end face of the inner sleeve 7 is provided with cooling water holes, which are connected to the annular groove of the base 2 to form a second cooling channel. This cooling channel is mainly used to cool the rotor part of the direct drive torque motor 3. The coolant enters the annular groove of the base 2 through the cooling water holes on the end face of the inner sleeve 7, circulating and cooling the heat generated by the rotor of the direct drive torque motor 3 during operation, ensuring that the rotor part of the direct drive torque motor 3 can also work at a suitable temperature, improving the working stability and reliability of the entire direct drive torque motor 3.

[0039] Furthermore, the crossed roller bearing 4 includes an outer ring and an inner ring, both of which are integral structures. The outer ring is fixed in the inner hole of the transition plate 10 by an interference fit, and is fixed at the bottom by a lower pressure plate 6. This interference fit ensures the tight connection between the outer ring and the transition plate 10, guaranteeing the stability of the outer ring during the rotation of the worktable 1. The inner ring is installed on the shoulder of the spindle 8 by an interference fit and is clamped by an upper pressure plate 11. The function of the spindle 8 shoulder and the upper pressure plate 11 is to fix the inner ring of the crossed roller bearing 4 from both the top and bottom directions, preventing axial displacement of the inner ring during operation. A grindable adjusting shim 12 is provided between the upper pressure plate 11 and the inner ring of the crossed roller bearing 4. During installation, the pressure of the upper pressure plate 11 on the inner ring can be precisely adjusted by adjusting the thickness of the grindable adjusting shim 12, thereby ensuring the installation accuracy of the inner ring and ensuring that the crossed roller bearing 4 can work normally and withstand the axial and radial forces of the worktable 1 and the workpiece during operation.

[0040] In the circular grating assembly, flange 15 is fixed to the center hole of worktable 1, providing an installation base for the entire circular grating assembly. Connecting shaft 17 is connected to flange 15 through transition plate 14, and the relative axial position of connecting shaft 17 is adjusted by adjusting shim 16, which can realize the precision assembly of connecting shaft 17 and inner hole of circular grating, ensuring the fit accuracy between the two during operation. Sealing flange 13 seals the center hole of worktable 1 with O-ring to prevent coolant from seeping in.

[0041] During turning and milling, coolant may be present around the worktable 1. The sealing flange 13 and O-ring serve two purposes: first, to prevent coolant from damaging the circular grating and encoder, thus ensuring the normal operation of the circular grating assembly; second, to prevent coolant from flowing into the interior and corroding the crossed roller bearings, and causing oil-water mixing. The direct-drive torque motor 3 drives the transition plate 10 to rotate the worktable 1. The direct-drive method eliminates intermediate transmission links, offering advantages such as simple structure, no backlash, smooth operation, and good low-speed characteristics. It also eliminates the high losses associated with transmission, enabling precise indexing and ensuring good stability and high accuracy for the worktable 1. In turning mode, constant-speed cutting and thread machining are achieved through the encoder. The encoder accurately monitors parameters such as the rotational speed of the worktable 1 and controls the drive of the direct-drive torque motor 3 according to a preset program, ensuring a constant cutting speed during turning and accurate thread machining. During milling, a circular grating is used for full closed-loop position detection. The circular grating can monitor the position information of the worktable 1 in real time and feed it back to the control system, thereby realizing full closed-loop control. This helps to improve the accuracy of milling and ensure the accuracy of milling feed and precision indexing of the worktable 1.

[0042] The rolling elements of the crossed roller bearing 4 are tapered rollers or cylindrical rollers, arranged at a 90° angle. The intersection of the extended rolling surfaces of the rollers is located on the bearing's rotation centerline, and the rolling elements perform only pure rolling motion. This 90° cross arrangement allows the axial force to be evenly transmitted to the inner and outer rings of the bearing through multiple rolling elements. Regarding radial force, the cross arrangement of adjacent rollers allows the radial force to be transmitted to the inner and outer rings through the radial support of the rolling elements. Furthermore, the shape and arrangement of the tapered or cylindrical rollers increase the stability of the radial support. For bearing overturning moments, this structure ensures that the rolling elements can generate a corresponding torque balance when the bearing is subjected to an overturning moment, guaranteeing normal bearing operation.

[0043] Reference Figure 1The cage of the crossed roller bearing 4 is a separate structure made of brass. The rolling elements are loaded into the raceway through the filling holes and then sealed and secured by the filling plug. The separate cage structure facilitates the loading of the rolling elements and the assembly of the bearing. During manufacturing, since the rolling elements need to be loaded into the raceway through the filling holes, loading the rolling elements would be very difficult, or even impossible, if the cage were a single piece. The separate structure allows a portion of the cage to be removed during the loading of the rolling elements, providing sufficient space for the loading operation. This structure also facilitates easy inspection and replacement of components such as the rolling elements and cage when the bearing fails or requires maintenance. Furthermore, brass has moderate strength and hardness, capable of withstanding the forces exerted on the cage by the rolling elements during bearing operation without easily deforming or being damaged. At the same time, brass has good wear resistance, reducing wear during prolonged contact and relative movement with the rolling elements, thus extending the service life of the cage. Brass also possesses excellent thermal conductivity, effectively dissipating heat generated by the rolling elements during bearing operation and preventing overheating due to heat buildup. During bearing operation, the rolling elements are subjected to various forces. Without the sealing and securing of the packing plug, the rolling elements may dislodge from the packing hole, leading to bearing failure. The packing plug, through an interference fit with the packing hole, firmly confines the rolling elements within the raceway, preventing them from dislodging. Simultaneously, the sealing effect of the packing plug also prevents external impurities from entering the raceway. In the machine tool working environment, dust, chips, and other impurities may be present. If these enter the raceway, they will accelerate the wear of the rolling elements and raceway, affecting the bearing's service life and performance. The sealing effect of the packing plug effectively blocks these impurities, maintaining the cleanliness of the raceway.

[0044] Reference Figure 1 The upper part of the sleeve 5 has a stop, and the cover 9 is pressed into the stop to fix the stator of the direct drive torque motor 3. An inner sleeve 7 is provided between the rotor of the direct drive torque motor 3 and the base 2. The rotor and the inner sleeve 7 have relative movement. The inner sleeve 7 is fixed to the base 2 by screws. The cooling water holes on its end face and the annular groove of the base 2 form a coolant circulation loop to circulate and cool the heat generated by the rotor of the direct drive torque motor 3 during operation. When the cover 9 is pressed into the stop, due to the dimensional accuracy and cylindricity of the stop, a large frictional force is generated between the cover 9 and the sleeve 5, which effectively prevents the stator of the direct drive torque motor 3 from moving in the axial direction. At the same time, it also ensures the circumferential positioning of the cover 9 and the sleeve 5, preventing the stator from rotating circumferentially, thus ensuring the stability of the stator of the direct drive torque motor 3 during operation. Under the action of the water pump, the coolant enters the cooling water hole on the end face of the inner sleeve 7 through an inlet, and then flows into the annular groove of the base 2. The coolant can be evenly distributed in the annular groove and carry away the heat of the surrounding components. After that, the coolant flows out from the outlet of the annular groove, and after being cooled by the radiator and other components of the cooling system, it re-enters the circulation system.

[0045] Reference Figure 2 The circular grating assembly also includes a support sleeve 19 and a support 18. The support sleeve 19 is mounted on the main shaft 8, and the support 18 is fixed to the support sleeve 19. The encoder housing is connected to the support 18 by screws. The encoder coupling meshes with the small shaft at the end of the connecting shaft 17. The circular grating housing is positioned and connected to the support 18 through a locating stop. The inner hole of the circular grating meshes with the connecting shaft 17. The encoder housing is connected to the support 18 by screws. This connection method is simple and easy to install and disassemble. Tightening the screws diagonally ensures even force distribution on the encoder housing, preventing deformation or loose connections due to uneven force distribution, thus ensuring the stability of the encoder during operation. The meshing of the encoder coupling with the small shaft at the end of the connecting shaft 17 is for accurate transmission of motion and signals. The circular grating housing is positioned and connected to the support 18 through a locating stop. The dimensions of the locating stop ensure the correct installation position of the circular grating housing and guarantee the relative positional accuracy of the circular grating with other components, thereby improving the working accuracy of the entire circular grating assembly. The precise meshing of the encoder coupling, the inner bore of the circular grating, and the connecting shaft 17 helps improve signal transmission and detection accuracy. During operation, the encoder accurately acquires the motion information of the worktable 1 through the coupling and connecting shaft 17, and converts it into electrical signals for transmission. The precise installation of the inner bore of the circular grating and the connecting shaft 17 ensures the working position accuracy of the circular grating, thereby improving the detection accuracy of the circular grating for the position of the worktable 1. The robust connection between the encoder housing and the support 18, and between the circular grating housing and the support 18, improves the structural stability of the entire circular grating assembly. During the rotation of the worktable 1, the stable structure reduces vibration and sway, thereby avoiding signal interference or detection errors caused by structural instability. At the same time, the structural stability also helps extend the service life of the circular grating assembly and reduce component damage caused by vibration and impact.

[0046] Reference Figure 1The outer ring of the crossed roller bearing 4 is fixed to the bottom of the inner hole of the transition plate 10 by the lower pressure plate 6, and the inner ring is fixed to the shoulder of the spindle 8 by the upper pressure plate 11 and the grindable adjusting shim 12. The thickness of the grindable adjusting shim 12 is matched with the axial preload by grinding. The principle of fixing the outer ring of the crossed roller bearing 4 by the lower pressure plate is that the pressure generated by the connection between the pressure plate and the transition plate 10 presses the outer ring tightly against the bottom of the inner hole of the transition plate 10. This fixing method can prevent the outer ring from axial and radial displacement during operation, and ensure the relative position stability between the outer ring and the transition plate 10. The control of bolt tightening torque and sequence is to ensure even distribution of pressure on the outer ring by the pressure plate, avoiding excessive or insufficient local pressure that could affect the fixing effect. The upper pressure plate 11, through the pressure generated by the bolt connection, fixes the inner ring to the shoulder of the spindle 8. The grindable adjusting shim 12 serves to adjust the axial position and preload of the inner ring. The grindable adjusting shim 12 can precisely control the axial relationship between the inner ring and the spindle 8, ensuring accurate axial positioning of the inner ring and allowing adjustment of the axial preload as needed, thereby improving the bearing's performance. During bearing operation, appropriate axial preload can improve the bearing's rigidity, rotational accuracy, and load-bearing capacity.

[0047] The worktable 1 and the transition plate 10 are connected by screws and pins. The transition plate 10 rotates synchronously with the rotor of the direct-drive torque motor 3, driving the worktable 1, flange 15, and connecting shaft 17 to achieve dual-mode drive control. The pins are used to precisely position the relative positions of the worktable 1 and the transition plate 10. Due to the interference fit between the pin and the pin hole, when the pin is inserted into the pin hole, it can prevent relative displacement of the worktable 1 and the transition plate 10 in the horizontal and vertical directions, ensuring that the connection position of the two is accurate. The screws tightly fix the worktable 1 and the transition plate 10 together through the action of the threads. The tightening torque is controlled to ensure that the screws generate sufficient clamping force to prevent the worktable 1 and the transition plate 10 from loosening during operation. The direct connection between the transition plate 10 and the rotor of the direct-drive torque motor 3, as well as the firm connection between the worktable 1 and the transition plate 10, ensures the synchronous rotation of the entire system. When the motor rotor applies torque to rotate the transition plate 10, due to the rigidity of the connection, the worktable 1 and its related components will inevitably rotate synchronously. This synchronicity ensures the consistency of movement under dual-mode drive.

[0048] The annular water tank of the stator of the direct-drive torque motor 3 and the annular water tank cooling water holes of the base 2 both adopt a spiral flow channel design, and the coolant flows in opposite directions. The water inlet of sleeve 5 is located at the lower end of its outer circle, and the water outlet is located at the upper end of its outer circle. The water inlet of inner sleeve 7 is located on the outer side of its end face, and the water outlet is located on the inner side of its end face, forming a convection cooling structure for the inner and outer rings of the direct-drive torque motor 3, thereby improving cooling efficiency. The opposite flow of coolant in inner sleeve 7 and sleeve 5 forms a convection cooling structure. In this convection cooling structure, the coolant in sleeve 5 enters from the lower end of its outer circle and flows upward, carrying away the heat of the stator of the direct-drive torque motor 3; the coolant in inner sleeve 7 enters from the outer side of its end face and flows inward, carrying away the heat of the rotor of the direct-drive torque motor 3. This convection method allows the heat of the inner and outer rings of the direct-drive torque motor 3 to be dissipated quickly, improving cooling efficiency. The combination of the spiral flow channel and the convection cooling structure significantly improves cooling efficiency. Compared to traditional straight flow channels and unidirectional coolant flow, this design allows the coolant to absorb heat more fully within the flow channels and dissipate it more quickly through convection. Under the same coolant flow rate and temperature conditions, it can remove more heat, thereby reducing the operating temperature of the direct-drive torque motor 3.

[0049] The working process of the milling and turning worktable is as follows: the direct drive torque motor 3 is powered on by the button station. The rotor of the direct drive torque motor 3 rotates, which drives the transition plate 10 to rotate. The transition plate 10 transmits the torque of the direct drive motor to the worktable 1, which drives the worktable 1 to rotate. The worktable 1 drives the encoder and circular grating connected to the connecting shaft 17 to rotate through the upper sealing flange 13 and flange 15 fixed at its center hole. In the turning state: the encoder can control constant speed cutting and thread cutting; in the milling state: when the worktable 1 is milling feed and precision indexing, it performs full closed-loop position detection.

[0050] In addition to the aforementioned milling and turning table, the present invention also provides a machine tool including the aforementioned milling and turning table structure. Other structures of this machine tool are based on existing technology and will not be described in detail here. Preferably, the machine tool is a vertical grinder, a vertical turning-grinding machine, or a vertical milling and turning machine, or other vertical machine tools.

[0051] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-precision direct-drive turning-milling worktable, characterized in that, include: Worktable, base, direct drive torque motor, crossed roller bearings, and circular grating assembly; The workbench is connected to the rotor of the direct drive torque motor via a transition plate. A sleeve is fixed on the base. The stator of the direct drive torque motor is fixed to the sleeve. The outer circle of the sleeve is provided with water inlet / outlet holes, which communicate with the annular water groove provided on the outer circle of the stator to form a first cooling channel. The rotor is embedded in the positioning stop of the transition plate and fixed. An inner sleeve is provided between the rotor and the base. The rotor and the inner sleeve have relative movement. The end face of the inner sleeve is provided with cooling water holes, which communicate with the annular groove provided on the base to form a second cooling channel. The crossed roller bearing includes an outer ring and an inner ring, both of which are integral structures; its outer ring is fixed to the bottom of the inner hole of the transition plate, and its inner ring is installed on the spindle shoulder and clamped by a lower pressure plate and an upper pressure plate. A grindable adjusting shim is provided between the upper pressure plate and the inner ring. The circular grating assembly includes a circular grating, an encoder, a connecting shaft, a flange, a sealing flange, and an adjusting shim. The flange is fixed to the center hole of the worktable. The connecting shaft is connected to the flange through a transition plate and assembled with the circular grating and encoder through the adjusting shim. The sealing flange seals the center hole of the worktable to prevent coolant from seeping in. The cooling water holes of the annular water tank of the stator and the annular water tank of the base of the direct drive torque motor are both designed with spiral flow channels, and the coolant flows in opposite directions. The water inlet of the sleeve is located at the lower end of its outer circle, and the water outlet is located at the upper end of its outer circle. The water inlet of the inner sleeve is located on the outer side of the end face, and the water outlet is located on the inner side of the end face, so as to form a convection heat dissipation structure for the inner and outer rings of the direct drive torque motor and improve the cooling efficiency.

2. The high-precision direct-drive turning-milling worktable according to claim 1, wherein, The rolling elements of the crossed roller bearing are tapered rollers or cylindrical rollers, and adjacent rollers are arranged in a 90° cross pattern.

3. The high-precision direct-drive turning-milling worktable according to claim 2, characterized in that, The cage of the crossed roller bearing is a separate structure and is made of brass.

4. The high-precision direct-drive turning-milling worktable according to claim 1, wherein, The upper part of the sleeve is provided with a stop, and a cover is pressed into the stop. The cover is used to fix the stator of the direct drive torque motor, and the outer circle of the cover is provided with cooling water holes. The cooling water holes are connected to the annular groove of the stator of the direct drive torque motor to form a coolant circulation loop.

5. The high-precision direct-drive turning-milling worktable according to claim 1, wherein, The inner sleeve is fixed to the base, and its end face cooling water hole forms a coolant circulation loop with the annular groove of the base.

6. The high-precision direct-drive turning-milling worktable according to claim 1, wherein, The circular grating assembly also includes a support sleeve and a support. The support sleeve is mounted on the main shaft, and the support is fixed to the support sleeve. The encoder housing is connected to the support by screws. The encoder coupling meshes with the small shaft at the end of the connecting shaft. The circular grating housing is positioned and connected to the support by a positioning stop. The inner hole of the circular grating meshes with the connecting shaft.

7. The high-precision direct-drive turning-milling worktable according to claim 1, wherein, The outer ring of the crossed roller bearing is fixed to the bottom of the inner hole of the transition plate by the lower pressure plate, and the inner ring is fixed to the spindle shoulder by the upper pressure plate and the adjusting shim. The thickness of the grinding adjusting shim is matched with the axial preload by grinding.

8. The high-precision direct-drive turning-milling worktable according to claim 1, wherein, The worktable and the transition plate are connected by screws and pins. The transition plate rotates synchronously with the rotor of the direct drive torque motor, driving the worktable, flange, and connecting shaft to achieve dual-mode drive control.

9. A machine tool, characterized by Includes the high-precision direct-drive milling and turning worktable as described in any one of claims 1-8, wherein the machine tool is a vertical milling and turning machine, a vertical grinding machine, or a vertical milling and turning composite machine tool.

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