High-precision direct-drive type turn-milling workbench

Abstract

The invention provides a high-precision direct-drive type turn-milling workbench. The high-precision direct-drive type turn-milling workbench comprises a workbench body, a base, a direct-drive torque motor, a crossed roller bearing and a circular grating assembly. The workbench is connected with a rotor of the direct-drive torque motor through a transition disc, a sleeve is fixed to the base, a stator of the direct-drive torque motor is fixed to the sleeve, and a water inlet / outlet hole is formed in the outer circle of the sleeve and communicated with an annular water groove in the outer circle of the stator of the direct-drive torque motor to form a first cooling channel. A rotor of the direct-drive torque motor is embedded into the positioning spigot of the transition disc and fixed, an inner sleeve is arranged between the rotor of the direct-drive torque motor and the base, the rotor of the direct-drive torque motor and the inner sleeve move relatively, and a cooling water hole is formed in the end face of the inner sleeve and communicated with the annular groove of the base to form a second cooling channel. The turning and milling workbench has the characteristics of thermal symmetry structure, high dynamic and static rigidity, high rotation precision of the workbench base, good precision retentivity, large bearing load, high rotation speed and good manufacturability, and the cost of a machine tool can be greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of machine tools, and in particular to a high-precision direct-drive turning and milling workbench. Background Art

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

[0003] In recent years, with the vigorous development of the domestic 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 worktable rotary spindle is the core part of the vertical milling and turning machine. The rotation accuracy of the spindle will directly affect the roundness, cylindricity, runout and other accuracy of the processed parts, and the spindle structure used in the machine tool will affect the rotation diameter and worktable load-bearing capacity of the machine tool.

[0005] In existing technology, the spindle of a vertical milling and lathe table typically utilizes a combination of two thrust ball bearings, one large and one small, and a double-row cylindrical roller bearing. This typical structure involves the large thrust ball bearing carrying the table's axial forces, the small thrust ball bearing providing preload, and the double-row cylindrical roller bearing carrying the table's radial forces.

[0006] However, this structure also has certain defects. For machine tools of different specifications, the versatility of thrust ball bearings is poor, that is, thrust ball bearings of one specification can only be used for machine tools of corresponding specifications. The reason is that the load-bearing capacity and maximum speed of thrust ball bearings have certain limitations. For example, if a larger thrust ball bearing is used for a smaller machine tool, the load capacity can be met, but the speed cannot be met; if a smaller thrust ball bearing is used for a larger machine tool, the speed can be met, but the load capacity cannot be met.

[0007] In addition, the installation process of double-row cylindrical roller bearings is relatively complicated, it is difficult to ensure the accuracy of their end face runout, and it is difficult to repair after wear, which will accordingly affect the processing accuracy of the workpiece. Summary of the Invention

[0008] The purpose of the present invention is to provide a high-precision direct-drive turning and milling workbench to address the deficiencies of the prior art.

[0009] The specific technical solutions are as follows: A high-precision direct-drive milling workbench, comprising: a workbench, a base, a direct-drive torque motor, a cross roller bearing and a circular grating assembly; The workbench is connected to the rotor of the direct-drive torque motor through 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, and is connected 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 surface of the inner sleeve is provided with cooling water holes, which are connected with the annular groove provided on the base to form a second cooling channel; The cross roller bearing comprises an outer ring and an inner ring, both of which are integral structures; the outer ring is fixed to the bottom of the inner hole of the transition plate, and the inner ring is mounted on the shoulder of the main shaft and clamped by a lower pressure plate and an upper pressure plate, and a grindable adjustment pad 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 adjustment pad. The flange is fixed to the center hole of the workbench. The connecting shaft is connected to the flange through a transition plate and is assembled with the circular grating and encoder through an adjustment pad. The sealing flange seals the center hole of the workbench to prevent coolant from seeping in.

[0010] Optionally, the rolling elements of the cross roller bearing are tapered rollers or cylindrical rollers, and adjacent rollers are arranged crosswise at 90°.

[0011] Optionally, the retaining frame of the cross roller bearing is a separate structure and is made of brass material.

[0012] Optionally, a stop is provided on the upper portion of the sleeve, and the cover is pressed into the stop to fix the stator of the direct-drive torque motor.

[0013] Optionally, the inner sleeve is fixed to the base, and the cooling water holes on its end surface and the annular groove of the base form a coolant circulation loop.

[0014] Optionally, the circular grating assembly also includes a support sleeve and a support, the support sleeve is installed on the main shaft, the support is fixed to the support sleeve, the encoder housing is connected to the support by screws, the encoder coupling is engaged with the small shaft at the end of the connecting shaft, and the circular grating housing is positioned and connected to the support through a positioning stop.

[0015] Optionally, the outer ring of the cross roller bearing is fixed to the bottom of the inner hole of the transition plate through a lower pressure plate, and the inner ring is fixed to the main shaft shoulder through an upper pressure plate and an adjustment pad. The thickness of the adjustment pad can be ground to match the axial preload by grinding.

[0016] Optionally, the workbench is connected to the transition plate by screws and pins, and the transition plate rotates synchronously with the rotor of the direct-drive torque motor, driving the workbench, flange, and connecting shaft to achieve dual-mode drive control.

[0017] Optionally, the cooling water holes of the annular water groove of the stator of the direct-drive torque motor and the annular water groove of the base both adopt a spiral flow channel design, and the coolant flows in opposite directions. The water inlet hole of the sleeve is located at the lower end of its outer circle, and the water outlet hole is located at the upper end of the outer circle. The water inlet hole of the inner sleeve is located on the outside of the end face, and the water outlet hole is located on the inside 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, thereby improving the cooling efficiency.

[0018] A machine tool comprises the high-precision direct-drive turning-milling workbench described above, wherein the machine tool is a vertical milling-lathe, a vertical grinder or a vertical turning-milling compound machine tool.

[0019] Compared with the prior art, the present invention has the following beneficial effects: The present invention utilizes a direct-drive torque motor to directly drive the worktable, resulting in a simple structure, zero backlash, smooth operation, and excellent low-speed characteristics. This eliminates the high losses associated with transmission, enabling precise indexing and ensuring excellent worktable stability and precision. Furthermore, the cross-roller bearings employed offer high speeds and high load-bearing capacity, capable of withstanding axial and radial forces and overturning torque from external loads. The turning and milling table of the present invention features a thermally symmetrical structure, high dynamic and static rigidity, high table base rotational accuracy, excellent precision retention, high load-bearing capacity, high speed, and excellent processability, significantly reducing machine tool costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the working structure of a high-precision direct-drive turning and milling workbench provided by the present invention; Figure 2 for Figure 1 The structure diagram at the center of letter A is enlarged.

[0021] In the figure: 1. workbench; 2. base; 3. direct-drive torque motor; 4. cross-roller bearing; 5. sleeve; 6. lower pressure plate; 7. inner sleeve; 8. main shaft; 9. cover; 10. transition plate; 11. upper pressure plate; 12. grindable adjustment pad; 13. sealing flange; 14. transition plate; 15. flange; 16. adjustment pad; 17. connecting shaft; 18. support; 19. support sleeve. DETAILED DESCRIPTION

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0023] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0025] The present invention provides a high-precision direct-drive milling table, referring to Figure 1-Figure 2 ,include: Workbench 1, base 2, direct drive torque motor 3, cross roller bearing 4 and circular grating assembly; The workbench 1 is connected to the rotor of the direct-drive torque motor 3 through a transition plate 10. A sleeve 5 is fixed to 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 is 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 surface 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; The crossed roller bearing 4 comprises an outer ring and an inner ring, both of which are integral structures. The outer ring is fixed to the bottom of the inner hole of the transition plate 10 by an interference fit, while the inner ring is mounted to the shoulder of the main shaft 8 by an interference fit and clamped by the lower pressure plate 6 and the upper pressure plate 11. A grindable adjustment pad 12 is provided between the upper pressure plate 11 and the inner ring. The circular grating assembly includes a circular grating, an encoder, a connecting shaft 17, a flange 15, a sealing flange 13, and an adjustment pad 16. The flange 15 is fixed to the center hole of the workbench 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 encoder through the adjustment pad 16. The sealing flange 13 seals the center hole of the workbench 1 with an O-ring to prevent coolant from seeping in. The direct-drive torque motor 3 drives the transition plate 10 to rotate the worktable 1. In the turning state, the encoder is used to achieve constant speed cutting and thread processing, and in the milling state, the circular grating is used for full closed-loop position detection.

[0026] Specifically, in this embodiment, in terms of cooling, 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 coolant provided by the water cooler enters the annular water groove 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 the sleeve 5, and cools the stator of the direct-drive torque motor 3 when it is working, effectively taking away the heat generated by the motor, and preventing the motor from affecting performance or being damaged due to overheating.

[0027] 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. The connection between the rotor and the transition plate 10 by screws and pins ensures that the rotor of the direct-drive torque motor 3 can be stably connected to the workbench 1, so that the workbench 1 can be effectively driven 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, and the rotor and the inner sleeve 7 have relative movement. The inner sleeve 7 plays a role in auxiliary cooling and also provides a structural basis for the setting of the cooling system. The end face of the inner sleeve 7 is provided with a cooling water hole, which is 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 hole on the end face of the inner sleeve 7, and circulates the heat generated by the rotor of the direct-drive torque motor 3 during operation to ensure that the rotor part of the direct-drive torque motor 3 can also work at a suitable temperature, thereby improving the working stability and reliability of the entire direct-drive torque motor 3.

[0028] In addition, the crossed roller bearing 4 includes an outer ring and an inner ring, and the inner ring and the outer ring are both integral structures; the outer ring is fixed in the inner hole of the transition plate 10 by an interference fit, and the bottom is fixed by the lower pressure plate 6. This interference fit method can ensure the tightness of the connection between the outer ring and the transition plate 10, and ensure the stability of the outer ring during the rotation of the workbench 1; the inner ring is installed on the shoulder of the main shaft 8 by an interference fit, and is clamped by the upper pressure plate 11. The function of the shoulder of the main shaft 8 and the upper pressure plate 11 is to fix the inner ring of the crossed roller bearing 4 from the upper and lower directions to prevent the inner ring from axial displacement during operation. A grindable adjustment pad 12 is provided between the upper pressure plate 11 and the inner ring of the crossed roller bearing 4. During the installation process, the pressure of the upper pressure plate 11 on the inner ring can be accurately adjusted by adjusting the thickness of the grindable adjustment pad 12, thereby ensuring the installation accuracy of the inner ring, ensuring that the crossed roller bearing 4 can work normally, and withstand the axial force and radial force of the workbench 1 and the workpiece during operation.

[0029] In the circular grating assembly, the flange 15 is fixed to the center hole of the workbench 1, providing an installation base for the entire circular grating assembly. The connecting shaft 17 is connected to the flange 15 through the transition plate 14, and the axial relative position of the connecting shaft 17 is adjusted by the adjustment pad 16. The precise assembly of the connecting shaft 17 and the inner hole of the circular grating can be achieved, ensuring the matching accuracy between the two during operation. The sealing flange 13 seals the center hole of the workbench 1 through an O-ring to prevent coolant from seeping in.

[0030] During turning and milling, coolant may be present around the worktable 1. The sealing flange 13 and O-ring provide two key sealing functions: first, they prevent coolant from damaging the circular grating and encoder, thereby ensuring the proper functioning of the circular grating assembly; and second, they prevent coolant from flowing into the internal structure, corroding the cross-roller bearings and causing oil-water mixing. A direct-drive torque motor 3 drives the transition plate 10 to rotate the worktable 1. This direct drive eliminates the need for intermediate transmission links and offers advantages such as a simple structure, no backlash, smooth operation, and excellent low-speed characteristics. It also eliminates the high losses associated with transmission, enabling precise indexing and ensuring excellent stability and precision for the worktable 1. During turning, an encoder is used to achieve constant-speed cutting and threading. 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 enabling accurate threading. In the milling state, full closed-loop position detection is performed through the circular grating. The circular grating can monitor the position information of the workbench 1 in real time and feed it back to the control system, thereby realizing full closed-loop control, which helps to improve the accuracy of milling processing and ensure the accuracy of milling feed and precision indexing of the workbench 1.

[0031] The rolling elements of the crossed roller bearing 4 are tapered rollers or cylindrical rollers. Adjacent rollers are arranged at 90° crosswise, and the intersection of the extended lines of the rolling surfaces of the rollers is located on the bearing's rotation centerline. The rolling elements only perform pure rolling during movement. The 90° crosswise arrangement allows the bearing to withstand axial force, and the axial force can be evenly transmitted to the inner and outer rings of the bearing through multiple rolling elements. In terms of bearing radial force, due to the crosswise arrangement of adjacent rollers, the radial force can be transmitted to the inner and outer rings through the support of the rolling elements in the radial direction. At the same time, the shape and arrangement of the tapered rollers or cylindrical rollers also increase the stability of the radial support. As for bearing overturning torque, this structure enables the rolling elements to generate a corresponding torque balance when the bearing is subjected to overturning torque, thereby ensuring the normal operation of the bearing.

[0032] Reference Figure 1The cage of the crossed roller bearing 4 is a split-type structure made of brass. The rolling elements are loaded into the raceways through the loading holes and then sealed and secured by a loading plug. The split-type cage facilitates the loading of the rolling elements and the assembly of the bearing. During the manufacturing process, since the rolling elements must be loaded into the raceways through the loading holes, loading the rolling elements would be extremely difficult, or even impossible, if the cage were a monolithic structure. The split-type structure allows for the removal of a portion of the cage during the loading of the rolling elements, providing ample space for the loading operation. This structure also facilitates the inspection and replacement of components such as the rolling elements and cage in the event of a bearing failure or repair. Furthermore, brass has moderate strength and hardness, capable of withstanding the forces exerted on the cage by the rolling elements during operation, without easily deforming or damaging. Furthermore, brass has good wear resistance, reducing wear during prolonged contact and relative motion with the rolling elements, thereby extending the service life of the cage. Brass also has excellent thermal conductivity, effectively conducting away the heat generated by the rolling elements during bearing operation, preventing excessive bearing temperatures due to heat buildup. During bearing operation, the rolling elements are subject to various forces. Without the sealing and securing of a packing plug, the rolling elements could escape from the packing hole, causing bearing failure. The packing plug, through its interference fit with the packing hole, securely confines the rolling elements within the raceway, preventing them from escaping. The packing plug's sealing action also prevents foreign matter from entering the raceway. In a machine tool operating environment, impurities such as dust and swarf may be present. If these impurities enter the raceway, they can exacerbate wear on the rolling elements and raceway, affecting the bearing's service life and performance. The packing plug's seal effectively blocks these impurities, keeping the raceway clean.

[0033] Reference Figure 1 A stopper is provided on the upper part of the sleeve 5, and the cover 9 is pressed into the stopper 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, and the rotor and the inner sleeve 7 have relative movement. The inner sleeve 7 is fixed to the base 2 by screws, and its end surface cooling water hole and the annular groove of the base 2 form a coolant circulation loop for circulating cooling of the heat generated by the rotor of the direct-drive torque motor 3 during operation. When the cover 9 is pressed into the stopper, due to the dimensional accuracy and cylindricity of the stopper, a large friction force is generated between the cover 9 and the sleeve 5, which can effectively prevent the stator of the direct-drive torque motor 3 from moving in the axial direction. At the same time, it also ensures the positioning of the cover 9 and the sleeve 5 in the circumferential direction, preventing the stator from circumferential rotation, thereby 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 from an inlet, and then flows into the annular groove of the base 2. The coolant can be evenly distributed in the annular groove and take away the heat of the surrounding components. After that, the coolant flows out from the outlet of the annular groove, passes through the radiator and other components of the cooling system for heat dissipation, and then re-enters the circulation system.

[0034] 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 via screws. The encoder's coupling engages with the small shaft at the end of the connecting shaft 17. The circular grating housing is positioned and connected to the support 18 via a locating stop, and the inner hole of the circular grating engages with the connecting shaft 17. The encoder housing is connected to the support 18 via screws. This connection method is simple and easy to install and disassemble. Tightening the screws in a diagonal order can ensure uniform force on the encoder housing, preventing deformation or loose connection caused by uneven force, thereby ensuring the stability of the encoder during operation. The engagement of the encoder's coupling with the small shaft at the end of the connecting shaft 17 is to accurately transmit motion and signals. The circular grating housing is positioned and connected to the support 18 via a locating stop. The size of the locating stop ensures the correct installation position of the circular grating housing and the relative position accuracy of the circular grating and other components, thereby improving the operating accuracy of the entire circular grating assembly. The precise engagement of the encoder's coupling, the inner hole of the circular grating, and the connecting shaft 17 helps to improve signal transmission and detection accuracy. During operation, the encoder accurately obtains the motion information of the workbench 1 through the coupling and the connecting shaft 17, and converts it into an electrical signal for transmission. The precise installation of the inner hole 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 on the position of the workbench 1. The stable connection between the encoder housing and the support 18, as well as the circular grating housing and the support 18, improves the structural stability of the entire circular grating assembly. During the rotation of the workbench 1, the stable structure can reduce vibration and shaking, thereby avoiding signal interference or detection errors caused by structural instability. At the same time, the stability of the structure also helps to extend the service life of the circular grating assembly and reduce component damage caused by vibration and impact.

[0035] Reference Figure 1The outer ring of the crossed roller bearing 4 is secured to the bottom of the inner bore of the transition plate 10 via the lower pressure plate 6. The inner ring is secured to the shoulder of the spindle 8 via the upper pressure plate 11 and a grindable adjustment pad 12. The thickness of the grindable adjustment pad 12 is ground to match the axial preload. The lower pressure plate secures the outer ring of the crossed roller bearing 4 by applying pressure generated by the connection between the pressure plate and the transition plate 10, pressing the outer ring tightly against the bottom of the inner bore of the transition plate 10. This securing method prevents axial and radial displacement of the outer ring during operation, ensuring a stable relative position between the outer ring and the transition plate 10. The tightening torque and tightening sequence of the bolts are controlled to evenly distribute the pressure of the pressure plate on the outer ring, avoiding localized pressure that could affect the securing effect. The upper pressure plate 11 secures the inner ring to the shoulder of the spindle 8 through the pressure generated by the bolted connection. The grindable adjustment pad 12 adjusts the axial position and preload of the inner ring. The grindable adjustment pad 12 precisely controls the axial relationship between the inner ring and the spindle 8, ensuring accurate axial positioning of the inner ring. The axial preload can be adjusted as needed, thereby improving the operating performance of the bearing. During operation, an appropriate axial preload can improve the bearing's stiffness, rotational accuracy, and load-bearing capacity.

[0036] The worktable 1 and transition plate 10 are connected via 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 precisely position the worktable 1 and transition plate 10 relative to each other. Due to the interference fit between the pins and the pin holes, once inserted, the pins prevent horizontal and vertical displacement of the worktable 1 and transition plate 10, ensuring a precise connection. The screws securely fasten the worktable 1 and transition plate 10 together through their threads. The tightening torque is controlled to ensure sufficient clamping force to prevent loosening of the worktable 1 and transition plate 10 during operation. The direct connection between the transition plate 10 and the rotor of the direct-drive torque motor 3, as well as the secure connection between the worktable 1 and transition plate 10, ensures synchronous rotation of the entire system. When the motor rotor applies torque to rotate the transition plate 10, the rigidity of the connection ensures synchronous rotation of the worktable 1 and its associated components. This synchronization ensures consistent motion under dual-mode drive.

[0037] The annular water trough of the stator of the direct-drive torque motor 3 and the annular water trough 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 the sleeve 5 is located at the lower end of its outer circle, and the water outlet is located at the upper end of the outer circle. The water inlet of the inner sleeve 7 is located on the outside of the end face, and the water outlet is located on the inside of the end face, forming a convection heat dissipation structure for the inner and outer rings of the direct-drive torque motor 3, thereby improving cooling efficiency. The coolant flows in opposite directions in the inner sleeve 7 and sleeve 5 to form a convection heat dissipation structure. In this convection heat dissipation structure, the coolant in the sleeve 5 enters from the lower end of the outer circle, flows upward, and removes heat from the stator of the direct-drive torque motor 3; the coolant in the inner sleeve 7 enters from the outside of the end face, flows inward, and removes heat from the rotor of the direct-drive torque motor 3. This convection method can quickly dissipate heat from the inner and outer rings of the direct-drive torque motor 3, improving cooling efficiency. The combination of the spiral flow channel and the convection heat dissipation structure significantly improves cooling efficiency. Compared to traditional linear channels and unidirectional coolant flow, this design allows the coolant to more fully absorb heat within the channel and dissipate it more quickly through convection. Under the same coolant flow and temperature conditions, it can remove more heat, thereby reducing the operating temperature of the direct-drive torque motor 3.

[0038] The working process of the turning and milling workbench is as follows: the direct-drive torque motor 3 is powered on through the button station, the rotor of the direct-drive torque motor 3 rotates to drive the transition plate 10 to rotate, the transition plate 10 transmits the torque of the direct-drive motor to the workbench 1 to drive the workbench 1 to rotate, and the workbench 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 threading; in the milling state, full-closed-loop position detection is performed during the milling feed and precision indexing of the workbench 1.

[0039] In addition to the aforementioned turning and milling table, the present invention further provides a machine tool including the aforementioned turning and milling table structure. The other structures of the machine tool are described in detail in the prior art and are not further described herein. Preferably, the machine tool is a vertical machine tool such as a vertical grinder, a vertical turning and grinding machine, or a vertical turning and milling machine.

[0040] The above are only preferred embodiments of the present invention and do not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-precision direct-drive turning and milling table, characterized in that: include: Workbench, base, direct drive torque motor, cross roller bearing and circular grating assembly; The workbench is connected to the rotor of the direct-drive torque motor through 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, and is connected 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 surface of the inner sleeve is provided with cooling water holes, which are connected with the annular groove provided on the base to form a second cooling channel; The cross roller bearing comprises an outer ring and an inner ring, both of which are integral structures; the outer ring is fixed to the bottom of the inner hole of the transition plate, and the inner ring is mounted on the shoulder of the main shaft and clamped by a lower pressure plate and an upper pressure plate, and a grindable adjustment pad 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 adjustment pad. The flange is fixed to the center hole of the workbench. The connecting shaft is connected to the flange through a transition plate and is assembled with the circular grating and encoder through an adjustment pad. The sealing flange seals the center hole of the workbench to prevent coolant from seeping in.

2. The high-precision direct-drive turning and milling table according to claim 1, characterized in that: The rolling elements of the cross roller bearing are tapered rollers or cylindrical rollers, and adjacent rollers are arranged crosswise at 90 degrees.

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

4. The high-precision direct-drive milling table according to claim 1, characterized in that: 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. The cooling water holes on the outer circle of the cover and the stator annular groove of the direct-drive torque motor form a coolant circulation loop.

5. The high-precision direct-drive milling table according to claim 1, characterized in that: The inner sleeve is fixed to the base, and the cooling water holes on the end surface of the inner sleeve and the annular groove of the base form a cooling liquid circulation loop.

6. The high-precision direct-drive milling table according to claim 1, characterized in that: The circular grating assembly also includes a support sleeve and a support. The support sleeve is installed on the main shaft, and the support is fixed to the support sleeve. The outer shell of the encoder is connected to the support by screws. The coupling of the encoder is engaged with the small shaft at the end of the connecting shaft. The outer shell of the circular grating is positioned and connected to the support through a positioning stop, and the inner hole of the circular grating is engaged with the connecting shaft.

7. The high-precision direct-drive milling table according to claim 1, characterized in that: The outer ring of the cross roller bearing is fixed to the bottom of the inner hole of the transition plate through the lower pressure plate, and the inner ring is fixed to the main shaft shoulder through the upper pressure plate and the adjustment pad. The thickness of the adjustment pad can be ground to match the axial preload.

8. The high-precision direct-drive milling table according to claim 1, characterized in that: The workbench 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 workbench, the flange and the connecting shaft to realize dual-mode drive control.

9. The high-precision direct-drive milling table according to claim 1, characterized in that: The cooling water holes of the annular water groove of the stator of the direct-drive torque motor and the annular water groove of the base both adopt a spiral flow channel design, and the coolant flows in opposite directions. The water inlet hole of the sleeve is located at the lower end of its outer circle, and the water outlet hole is located at the upper end of the outer circle. The water inlet hole of the inner sleeve is located on the outside of the end face, and the water outlet hole is located on the inside 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.

10. A machine tool, characterized in that: It comprises a high-precision direct-drive turning-milling workbench as described in any one of claims 1 to 9, and the machine tool is a vertical milling-lathe, a vertical grinder or a vertical turning-milling compound machine tool.

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