A high-precision temperature control turntable device and a temperature control method thereof

Abstract

The application discloses a high-precision temperature control rotary table device and a temperature control method thereof, belongs to the technical field of numerical control machine tool functional components, and aims to solve the problems of uneven cooling, large internal temperature difference and poor rotation precision stability caused by thermal deformation of the existing rotary table. The application adopts an integrally-formed concentric base as a mounting reference, configures a three-stage collaborative cooling architecture composed of a double-layer motor water jacket water cooling circuit, a bearing oil cooling circuit and a double-layer annular air cooling circuit, and combines a global temperature acquisition, a main and auxiliary double-closed-loop water cooling control, a hierarchical air cooling linkage, a dynamic threshold anti-shake, a hierarchical fault tolerance and a thermal error compensation control logic, so that the rotary table temperature is effectively controlled, the rotation precision retention is improved, and the application can be widely applied to high-precision machining scenes of high-end five-axis numerical control machine tools.

Description

Technical Field

[0001] This invention relates to the field of functional components of CNC machine tools, and in particular to a high-precision temperature-controlled rotary table device and its temperature control method. Background Technology

[0002] With the widespread application of five-axis linkage machining technology in the processing of aerospace structural components, precision optical molds, and core components of new energy vehicles, the CNC rotary table, as a core functional component of five-axis machine tools, directly determines the overall machining accuracy and efficiency through its rotational accuracy retention and operational stability. However, the internal asymmetric thermal deformation caused by the heating of the DD motor, bearing friction, and seal friction during rotary table operation is the core cause of rotary table accuracy drift and excessive machining errors. Currently, most conventional CNC rotary tables adopt a split-type base structure, where the coaxiality of various mounting bases is greatly affected by assembly accuracy, and the thermal expansion coefficients of components made of different materials differ. Anomalies can easily cause gap drift, further amplifying the impact of thermal deformation. Cooling systems often use a single water-cooling or oil-cooling architecture, which only dissipates heat from a single component such as the motor or bearing. This fails to achieve uniform temperature control across the entire turntable. Some turntable solutions that incorporate air cooling use direct vent designs, where cold air blowing directly onto local components can easily cause a larger temperature gradient, exacerbating asymmetric thermal deformation. Meanwhile, existing temperature control logic often uses simple threshold switching, resulting in high start-stop instability and large temperature fluctuations in the cooling circuit. It lacks fault tolerance and thermal error compensation mechanisms, which not only easily leads to false triggering shutdowns but also fails to offset the impact of residual thermal deformation on machining accuracy.

[0003] Chinese Patent CN116690241A discloses a high-precision milling and turning rotary table, relating to the field of machine tool rotary table technology. The rotary table includes: a slide with an internal cavity for mounting on a machine tool bed; a support sleeve connected inside the cavity; a bearing assembly with its inner rotating body connected to the outer side of the support sleeve; a torque motor with its stator connected to the inner side of the support sleeve and its rotor connected to the outer rotating body of the bearing assembly; a cooling groove between the stator and the inner side of the support sleeve; a worktable rotatably connected to the top of the cavity and connected to the outer rotating body of the bearing assembly; a water-cooling circuit system connected to the cooling groove; and an oil-cooling circuit system connected to the interior of the bearing assembly. This effectively removes heat generated by the torque motor and bearing assembly, controls the rotary table temperature, and mitigates the impact of temperature changes on the rotary table's accuracy, ensuring high precision and accuracy stability. The aforementioned method only employs a two-stage cooling architecture consisting of a single-layer stator cooling tank with water cooling and bearing oil cooling, lacking a forced air cooling circuit. Firstly, the single-layer water cooling tank has a low heat dissipation area, insufficient for high-power three-phase DD motors, leading to non-uniform thermal deformation. Secondly, the absence of an internal air cooling design prevents the removal of residual heat from the turntable, accelerating the aging of seals and lubricants over time. Furthermore, even if air cooling is subsequently added, direct cold air blowing onto the heat source surface will further widen local temperature differences. Therefore, those skilled in the art urgently need to address these technical issues. Summary of the Invention

[0004] To overcome the shortcomings and deficiencies of existing technologies, an integrated concentric base structure is adopted to eliminate coaxiality errors and thermal expansion gaps caused by separate assembly. Relying on a three-level synergistic cooling architecture of water cooling, oil cooling, and air cooling, plus a shielded split air outlet design, uniform heat dissipation is achieved throughout the entire area. Combined with dual closed-loop feedforward temperature control logic, dynamic threshold anti-shake control, and thermal error compensation mechanism, the temperature difference in the core area of ​​the turntable can be controlled within 1℃, effectively solving the problems of large thermal deformation and insufficient precision retention of existing turntables.

[0005] The technical solution adopted in this invention is a high-precision temperature control turntable device, including a turntable base and a worktable. The turntable base includes concentrically arranged bases A, B, C, and D. The worktable is mounted on a central rotating cylinder on base A via a flange connection plate. The central rotating cylinder is mounted on a central rotating shaft. The central rotating shaft is connected to a three-phase DD motor. The three-phase DD motor is installed between bases A and B. Bases A, B, C, and D are integrally formed.

[0006] The three-phase DD motor is externally fitted with at least two layers of motor stator water jackets. Temperature collectors are circumferentially installed on the outer wall of the base B and the inner wall of the base C. The temperature collectors are electrically connected to the junction box on the outer wall of the base D.

[0007] The outer wall of the base C is fitted with at least two layers of roller bearings. The inner wall of the base C is provided with a mounting seat with an opening facing the central rotating shaft. An L-shaped mounting plate is installed on the mounting seat. The outer air-cooled copper pipe is installed on the inner wall of the base D through the L-shaped mounting plate. A temperature sensor is also provided on the base D directly above the outer air-cooled copper pipe.

[0008] The top of the base A is also provided with a brake flange that is fitted on the central rotating cylinder. An L-shaped mounting plate is bolted to the top of the brake flange for installing the inner air-cooled copper pipe. The inner air-cooled copper pipe is located between the base A and the three-phase DD motor. The inner air-cooled copper pipe is connected to the outer air-cooled copper pipe. The inner air-cooled copper pipe and the outer air-cooled copper pipe are mounted on the L-shaped mounting plate through a T-connector to form an annular air-cooling channel.

[0009] The inner and outer air-cooled copper tubes are provided with at least four evenly arranged air outlets. The air outlets are fitted onto the outlet end of the tee connector. The outlet end of the tee connector is provided with a shielding cover. The shielding cover is fixed on the outlet end to prevent the air outlets from blowing directly into the turntable, so that the cold air blows out from both sides of the shielding cover.

[0010] A water-cooling cavity is provided between the three-phase DD motor and the roller bearing, and an oil-cooling cavity is provided between the base D and the roller bearing. The bottom of the turntable base is provided with multiple evenly arranged heat dissipation holes.

[0011] By adopting the above technical solution, the concentricity of the assembly and uniformity of heat conduction of the core components of the turntable are ensured by the integrated four-layer concentric base structure. This fundamentally avoids the problems of assembly gap drift and thermal deformation deviation caused by the difference in thermal expansion and contraction of the split assembly structure. At the same time, a multi-source cooling architecture is set up, which combines a double-layer motor stator water jacket, an independent water-cooled oil-cooled cavity and a double-layer annular air-cooled channel with a shield. This can not only achieve full coverage heat dissipation of core heat sources such as motors and bearings, but also avoid the problem of local temperature difference caused by cold air blowing directly on a single component. With the help of temperature acquisition devices distributed in different base layers, the temperature field inside the turntable can be monitored in the whole area. From the structural level, this provides a reliable foundation for high-precision temperature control of the turntable and effectively reduces the risk of asymmetric thermal deformation during the operation of the turntable.

[0012] Furthermore, the two-layer stator water jackets outside the three-phase DD motor have a spiral-wound water channel structure. The inlet of the stator water jacket is connected to the outlet of the external water chiller, and the outlet of the stator water jacket is connected to the inlet of the water cooling cavity. The water outlet of the water cooling cavity flows back to the external water chiller. The oil cooling cavity is arranged around the outer ring of the roller bearing for lubrication and cooling of the roller bearing. The bottom of the turntable base is an integrally formed layered base plate, and each layered base plate is provided with heat dissipation holes.

[0013] Furthermore, at least 18 temperature acquisition devices are provided in total, with at least 6 temperature acquisition devices arranged on the outer wall of base B and the inner wall of base C, and at least 6 temperature acquisition devices arranged directly above the outer layer of air-cooled copper pipe on base D. The temperature acquisition devices communicate with the turntable CNC system in real time through the junction box.

[0014] Furthermore, both the inner and outer air-cooled copper tubes are made of copper tubing. The inner air-cooled copper tubes are arranged circumferentially around the top of the three-phase DD motor stator, and the outer air-cooled copper tubes are arranged circumferentially around the inner wall of the base D. The vertical side of the L-shaped mounting plate is fixed to the mounting seat on the inner wall of the base C and the top of the brake flange by bolts. The horizontal side of the L-shaped mounting plate is connected to the tee connector. The inner or outer air-cooled copper tubes are fixed inside the turntable base by the tee connector.

[0015] Furthermore, the air outlet is directed towards the gap between the stator and the roller bearing of the three-phase DD motor, and the distance between the shield and the outlet end of the three-way connector is 3~5mm. After being blocked by the shield, the cold air is split radially to both sides, evenly covering the surface of the stator of the three-phase DD motor and the outer ring of the roller bearing.

[0016] This invention also discloses a high-precision temperature control method for a turntable, used to control a high-precision temperature control turntable device and regulate the temperature inside the turntable, comprising the following steps:

[0017] S1. Temperature data of various areas inside the turntable are collected in real time by temperature acquisition devices arranged on the outer wall of base B, the inner wall of base C, and base D. At the same time, the real-time power, current, speed, and load operating parameters of the three-phase DD motor are collected. The total heat generation power of the turntable is calculated based on the operating parameters. The formula for calculating the total heat generation power is: ;

[0018] in, This is the rated heating power of the three-phase DD motor. The power of frictional heat generation in the sealing component. This refers to the standby heat generation power of the hydraulic system.

[0019] S2. Three-level cooling coordinated control is adopted: water cooling control is performed through the double-layer motor stator water jacket and water cooling cavity outside the three-phase DD motor; roller bearing lubrication and cooling control is performed through the oil cooling cavity; and forced air cooling control is performed through the annular air cooling channel composed of inner and outer air cooling copper pipes.

[0020] S3. It adopts a water-cooling control architecture with a main loop-secondary loop dual closed loop and flow feedforward, and performs water-cooling and air-cooling linkage control.

[0021] S4. Dynamically adjust the cooling control threshold based on the turntable operating conditions and data from each temperature acquisition unit, and perform anti-shake switching control.

[0022] S5. Implements graded fault-tolerant control for temperature acquisition device and cooling circuit failures, and calculates thermal deformation based on temperature acquisition data, inputting it into the CNC system to perform real-time thermal error compensation.

[0023] Furthermore, the water cooling control in step S3 specifically includes:

[0024] The main circuit uses the temperature acquisition device on the inner wall of base C to collect the measured temperature of the three-phase DD motor stator and the preset target temperature to calculate the optimal inlet water temperature setting value of the water cooling system.

[0025] The secondary circuit uses the difference between the measured temperature collected by the water chiller outlet temperature acquisition device and the set value of the inlet water temperature to adjust the compressor frequency and heater duty cycle of the water chiller using PID control, so that the outlet water temperature is stabilized within the range of ±0.5℃ of the set value.

[0026] The flow feedforward module calculates the heat generation increment based on the real-time power / current of the three-phase DD motor, matches the corresponding cooling water flow increment, and adds it to the flow PID set value to adjust the cooling water flow in the water-cooled cavity and the motor stator water jacket in advance.

[0027] Furthermore, the water-cooling and air-cooling linkage control logic in step S3 is as follows:

[0028] When the temperature acquisition device on the inner wall of the base C detects that the stator temperature of the three-phase DD motor is higher than the water cooling trigger threshold, i.e., 5°C lower than the ambient temperature, only water cooling and oil cooling control will be activated.

[0029] When the temperature of the three-phase DD motor stator is detected to be higher than the air-cooling trigger threshold, i.e., 2°C lower than the ambient temperature, the annular air-cooling channel is activated at the same time. The air outlets of the inner and outer air-cooling copper tubes are split by the shielding cover and output cold air to cover the surface of the three-phase DD motor stator and roller bearing, avoiding non-uniform thermal deformation caused by local direct blowing.

[0030] The formula for calculating the minimum cooling flow rate of a water-cooled system is: ;

[0031] in, The specific heat capacity of cooling water, For the density of cooling water, To ensure the preset allowable temperature rise, the selected water chiller must meet the following requirements: cooling capacity ≥ 27.2KW and cooling flow rate ≥ 48.6L / min;

[0032] The formula for calculating the minimum airflow of an air-cooled system is: ;

[0033] in, The specific heat capacity of air, air density, This assumes a temperature rise.

[0034] Furthermore, the dynamic threshold adjustment and anti-shake control rules in step S4 are as follows: the hysteresis range of the inner cavity high temperature protection trigger threshold and recovery threshold is set to 3~5℃. When the temperature acquisition device on the outer wall of the base B detects that the roller bearing temperature is higher than 45℃, the high temperature trigger threshold is adjusted to 55℃.

[0035] When the ambient temperature is higher than 35℃, the high temperature trigger threshold is increased by 2~3℃; the high temperature protection logic is disabled for the first 2 minutes after the turntable starts to avoid false triggering.

[0036] The allowable temperature rise range under different operating conditions is as follows: 2~4℃ for low-speed / intermittent operation, 4~6℃ for medium-speed / continuous operation, 7~9℃ for high-speed / heavy-load operation, and ≤2℃ for high-precision machining.

[0037] Furthermore, the control logic of step S5 is specifically as follows:

[0038] During the fault-tolerant control phase, when a single temperature acquisition device fails, the system switches to the data from the redundant temperature acquisition device at the same location. If there is no redundant acquisition device, the system calls the pre-trained heat conduction model to estimate the temperature at the corresponding location to maintain operation.

[0039] When a single cooling circuit failure is detected, the operating power of the remaining normal cooling circuits is increased while the turntable is derated; when all cooling circuits fail or the temperature exceeds the maximum safety threshold, an emergency shutdown is triggered.

[0040] In the thermal error compensation stage, the data collected by the temperature acquisition device is input into the pre-trained thermal deformation prediction model, and the axial and radial thermal deformation of the worktable is output. The deformation is then used as the compensation value and input into the CNC system to correct the machining coordinates.

[0041] The beneficial effects of this invention are as follows:

[0042] 1. This invention, through an integrally molded four-layer concentric turntable base structure and a double-layer annular air-cooling channel design with a shielding cover, ensures the concentricity of the core component assembly and the uniformity of heat conduction, while avoiding the problem of local temperature difference caused by cold air blowing directly on a single component. It eliminates the cause of asymmetric thermal deformation from the structural level and greatly improves the accuracy retention during turntable operation.

[0043] 2. This invention achieves efficient heat dissipation of core heat sources such as motors and bearings through a three-level synergistic cooling architecture consisting of a double-layer spiral motor stator water jacket, a surrounding bearing oil cooling cavity, and an annular air cooling channel. At the same time, it is combined with a multi-area redundant temperature acquisition system to achieve accurate monitoring of the temperature field inside the turntable, providing a reliable hardware foundation and data support for high-precision temperature control.

[0044] 3. This invention effectively reduces temperature control lag and significantly improves temperature control accuracy by using a main and auxiliary dual closed-loop water cooling control architecture with flow feedforward, water cooling and air cooling hierarchical linkage logic, and dynamic threshold anti-shaking control rules that are adaptive to operating conditions. It achieves the optimal balance between cooling efficiency and operating energy consumption and can be adapted to the temperature control requirements of different processing scenarios.

[0045] 4. This invention improves the continuous operation stability of the equipment and reduces unnecessary downtime by using a graded fault-tolerant control mechanism for sensor and cooling circuit failures, as well as a real-time thermal error compensation strategy based on full-domain temperature data. At the same time, it further offsets residual thermal deformation and comprehensively improves the machining accuracy and operational reliability of the turntable. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0047] Figure 2 This is a schematic diagram of the structure of the removal workbench of the present invention;

[0048] Figure 3 For the present invention Figure 1 A cross-sectional view along the vertical direction;

[0049] Figure 4 This is a top view of the present invention;

[0050] Figure 5 For the present invention Figure 2 Enlarged diagram of section A in the middle;

[0051] Figure 6 This is a schematic diagram of the structure of the tee connector of the present invention;

[0052] Figure 7 This is a schematic diagram of the assembly of the outer water-cooling channel and the inner water-cooling channel of the present invention;

[0053] Figure 8 This is a flowchart of the method of the present invention;

[0054] Figure 9 This is a thermal analysis cloud diagram of the workbench of the present invention;

[0055] Figure 10 This is a thermal analysis cloud diagram of the turntable base of the present invention;

[0056] Figure 11 This is a schematic diagram of the water cooling control of the present invention;

[0057] Figure 12 This is a schematic diagram of the air-cooling control of the present invention.

[0058] Among them, 1-turntable base; 2-worktable; 3-base A; 4-base B; 5-base C; 6-base D; 7-flange connection plate; 8-central rotating cylinder; 9-central rotating shaft; 10-three-phase DD motor; 11-motor stator water jacket; 12-temperature acquisition device; 13-junction box; 14-roller bearing; 15-mounting seat; 16-L-type mounting plate; 17-outer air-cooled copper pipe; 18-brake flange; 19-bolt; 20-inner air-cooled copper pipe; 21-te-joint connector; 22-air outlet; 23-shield; 24-water-cooled cavity; 25-oil-cooled cavity; 26-heat dissipation hole; 27-layered base plate. Detailed Implementation

[0059] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0060] Reference Figure 1 , Figure 2 As can be seen, the core support structure of this high-precision temperature control turntable device is an integrally formed turntable base 1. The bases A3, B4, C5, and D6, which are concentrically arranged inside the turntable base 1, are integrally machined structures, which fundamentally solves the problem of concentricity deviation and thermal deformation deviation caused by uneven heat conduction in the assembly of split bases, and greatly improves structural consistency and thermal stability. The worktable 2 is fixed to the outside of the integrally formed central rotating cylinder 8 on the base A3 through the flange connecting plate 7. The central rotating shaft 9 installed inside the central rotating cylinder 8 is connected to the three-phase DD motor 10 for transmission. The three-phase DD motor 10 is installed between the base A3 and the base B4 to ensure the coaxiality of the core transmission components and avoid assembly gap drift under long-term operation.

[0061] The inlet of the two-layer spiral-wound stator water jacket 11 of the three-phase DD motor 10 is connected to the outlet of the external water chiller. The outlet is connected to the inlet of the water cooling channel 24 between the three-phase DD motor 10 and the two-layer roller bearing 14. The water from the water cooling channel 24 flows back to the external water chiller, forming a complete water cooling circuit. This improves the motor's heat dissipation efficiency and realizes the stepped utilization of cooling water. Combined with the oil cooling channel 25 set around the outer ring of the bearing between the base D6 and the roller bearing 14, it realizes the uniform discharge of bearing friction heat and solves the problems of insufficient heat dissipation and short service life of traditional bearing structures.

[0062] The outer wall of base C5 is fitted with at least two layers of roller bearings 14. An L-shaped mounting plate 16 is fixed to the mounting seat 15, whose opening faces the central rotating shaft 9, via bolts 19. The L-shaped mounting plate 16 is fixed with an outer layer of air-cooled copper tubing 17 that surrounds the inner wall of base D6 via a tee connector 21. Similarly, an L-shaped mounting plate 16 is fixed to the brake flange 18, which is mounted on the central rotating cylinder 8 at the top of base A3, via bolts 19. This L-shaped mounting plate 16 is fixed with an inner layer of air-cooled copper tubing 20 that surrounds the top of the stator of the three-phase DD motor 10 via a tee connector 21. Both the inner layer of air-cooled copper tubing 20 and the outer layer of air-cooled copper tubing 17 are made of copper. An annular air-cooling channel is formed by the preparation and interconnection of the components to achieve forced heat dissipation in the inner cavity, solving the problem of rapid aging of seals and grease caused by heat accumulation in the inner cavity of traditional structures; at least four air outlets 22 on the inner air-cooling copper tube 20 and the outer air-cooling copper tube 17 are fitted onto the outlet end of the tee connector 21. The distance between the fixed shield 23 at the outlet end and the outlet end is 3~5mm. The air outlets 22 face the gap between the stator and the roller bearing 14 of the three-phase DD motor 10. After being split by the shield 23, the cold air is evenly covered on both sides of the radial direction to cover the surface of the stator and the outer ring of the roller bearing 14, solving the problem of local temperature difference and asymmetric thermal deformation caused by direct air blowing on a single component in traditional air-cooling.

[0063] At least six temperature sensors 12 are arranged on the outer wall of base B4, the inner wall of base C5, and directly above the outer layer of air-cooled copper pipe 17 on base D6, for a total of at least 18 redundantly arranged temperature sensors 12. These sensors communicate in real time with the turntable CNC system through the junction box 13 on the outer wall of base D6, enabling full-coverage monitoring of the temperature field of the stator, bearings, and inner cavity inside the turntable. This provides accurate data support for high-precision temperature control while avoiding control logic disorder caused by single sensor failure. The layered base plate 27, which is integrally formed at the bottom of the turntable base 1, is evenly provided with heat dissipation holes 26 to enhance the natural heat exchange between the turntable and the external environment, further improving the overall heat dissipation efficiency and the stability of continuous operation of the equipment.

[0064] In one embodiment, refer to Figure 3As can be seen, the cooling water output from the external water chiller first flows into the two-layer spiral-wound stator water jacket 11 surrounding the three-phase DD motor 10, where it exchanges heat with the stator of the three-phase DD motor 10, removing most of the heat generated by the core heat source. The water from the stator water jacket 11 then flows into the water-cooling cavity 24 between the three-phase DD motor 10 and the roller bearing 14, further removing the conductive heat from the lower part of the turntable before flowing back to the external water chiller to complete the cycle. This cooling method solves the technical problems of insufficient heat dissipation area of ​​the traditional single-layer water cooling tank and excessive circumferential temperature difference of the stator under high-power operation. It significantly improves the heat exchange efficiency through the double-layer spiral water channel. At the same time, the stepped water design with the stator water jacket 11 and the water-cooling cavity 24 connected in series ensures the overall temperature uniformity of the three-phase DD motor 10 while improving the water cooling utilization rate. This can effectively reduce the risk of non-uniform thermal deformation of the motor stator and improve the operating accuracy and stability of the core transmission components of the turntable.

[0065] Lubricating oil continuously circulates within the oil-cooling cavity 25, which surrounds the base D6 and the roller bearing 14. During circulation, the lubricating oil directly contacts the outer ring of the roller bearing 14, providing sufficient lubrication to the rolling elements and raceways of the roller bearing 14 to reduce frictional losses. Simultaneously, it removes the frictional heat generated by the long-term operation of the roller bearing 14. After heat exchange, the lubricating oil is cooled by an external cooling unit and then flows back to the oil-cooling cavity 25 for further circulation. This cooling method solves the technical problems of traditional turntables lacking independent bearing cooling circuits, resulting in excessive bearing temperature rise, rapid grease aging, and short bearing life due to the inability to effectively dissipate frictional heat. The surrounding oil-cooling cavity 25 achieves uniform heat dissipation throughout the circumference of the roller bearing 14, controlling the bearing operating temperature within a reasonable range. This extends the bearing's service life and avoids radial thermal deformation caused by localized temperature rise, ensuring the turntable's rotational accuracy.

[0066] Compressed air cooled by the external refrigeration unit first enters the interconnected inner air-cooled copper pipe 20 and outer air-cooled copper pipe 17. The inner air-cooled copper pipe 20 is arranged circumferentially along the top of the stator of the three-phase DD motor 10 through the L-shaped mounting plate 16 fixed to the top of the brake flange 18 and the three-way connector 21. The outer air-cooled copper pipe 17 is arranged circumferentially along the inner wall of the base D6 through the L-shaped mounting plate 16 fixed to the mounting seat 15 on the inner wall of the base C5 and the three-way connector 21. After the cold air flows out through the air outlets 22 evenly arranged on the copper pipe, it is diverted by the shielding cover 23 at the outlet end of the three-way connector 21 and diffused radially to both sides, evenly covering the gap area between the stator surface of the three-phase DD motor 10 and the outer ring of the roller bearing 14. The hot air after heat exchange is discharged to the external environment through the heat dissipation holes 26 on the layered bottom plate 27 at the bottom of the turntable base 1. This cooling method solves the technical problems of traditional turntables lacking an internal cavity air-cooling circuit, which leads to accelerated aging of seals due to internal heat accumulation and excessive local temperature differences caused by direct cold air blowing on a single component. It achieves efficient exhaust of residual heat from the internal cavity through a double-layer annular air-cooling channel. At the same time, the diversion design of the shielding cover 23 avoids sudden local temperature changes caused by direct cold air blowing, ensuring the uniformity of the internal temperature field of the turntable. This can effectively prevent the generation of asymmetric thermal deformation, while slowing down the aging rate of internal seals and grease, and reducing equipment maintenance costs.

[0067] In one embodiment, refer to Figure 4 As can be seen, the bottom of the turntable base 1 is an integrally formed layered base plate 27. The layered base plate 27 adopts a double-layer stepped structure design. The upper base plate is directly sealed to the bottom of the base D6 as the lower sealing surface of the turntable cavity. The lower base plate is suspended and a 20-30mm air flow gap is reserved between it and the upper base plate. Multiple evenly arranged heat dissipation holes 26 are opened on the upper and lower base plates. The arrangement of the heat dissipation holes 26 avoids the mounting bolt holes and cooling water / oil / air interface positions on the bottom of the turntable. All the heat dissipation holes 26 are staggered on the upper and lower base plates. This setting solves the problem that the traditional turntable bottom only has a single-layer flat plate and no independent heat dissipation channel, which leads to the inability of hot air in the cavity to be discharged smoothly. The design avoids the problem of low heat transfer efficiency when the mounting surface contacts the machine tool bed, while also avoiding the defects of single-layer straight-out heat dissipation holes 26 that easily allow cutting fluid and dust impurities to enter and contaminate the internal cavity. On the one hand, the staggered heat dissipation holes 26 of the upper and lower layers can ensure air circulation between the inner cavity of the rotary table and the external environment, smoothly exhaust the hot air after air-cooled heat exchange, and enhance the natural heat dissipation effect. At the same time, the staggered arrangement structure can effectively prevent external cutting fluid, metal chips, and dust from entering the inner cavity of the rotary table, improving the protection performance of the internal cavity components. On the other hand, the double-layer structure of the layered base plate 27 reduces the direct contact area between the rotary table and the machine tool bed, reduces the interference of bed temperature fluctuations on the internal temperature field of the rotary table, and further improves the temperature stability and accuracy retention of the rotary table.

[0068] In one embodiment, refer to Figure 5 , Figure 6 and Figure 7 As can be seen, the inner layer air-cooled copper pipe 20 and the outer layer air-cooled copper pipe 17 of this device are connected by a three-way connector 21 to achieve the integration of pipeline connection and air outlet function. The three-way connector 21, which is fixed to the horizontal side of the L-shaped mounting plate 16, has three interfaces. Two of the horizontal interfaces are sealed and inserted into the adjacent inner layer air-cooled copper pipe 20 section and the outer layer air-cooled copper pipe 17 section, respectively, to achieve the overall connection of the double-layer annular air-cooling channel. The third interface, which is perpendicular to the gap between the stator and the roller bearing 14 of the three-phase DD motor 10, serves as the air outlet. The outer wall of the air outlet is fitted with a blower 22. The end of the air outlet is also fixed with a shield 23 with a distance of 3~5mm from the end face. After the compressed cold air is delivered to the three-way connector 21 through the inner layer air-cooled copper pipe 20 and the outer layer air-cooled copper pipe 17, one path continues to circulate along the air-cooled pipeline to ensure uniform cooling of the entire pipeline, while the other path flows out through the blower 22 at the air outlet. The outflowing cold air directly impacts the shield 23 and then is evenly distributed radially to both sides, eventually spreading to cover the stator surface of the three-phase DD motor 10 and the outer ring area of ​​the roller bearing 14. This structure solves the technical problems of poor pipeline sealing, complex assembly process, and uncontrollable air outlet direction caused by cold air blowing directly on a single component, resulting in excessive local temperature difference and asymmetric thermal deformation, which are inherent in traditional air-cooled pipelines that use segmented splicing and separate drilling for air outlets. On the one hand, the integrated design of the three-way connector 21 realizes both pipeline connection and air outlet functions, reducing the risk of pipeline leakage and assembly difficulty, and improving the operational reliability of the air-cooled system. On the other hand, the flow diversion and guiding effect of the shield 23 prevents cold air from directly blowing on local components, ensuring the uniformity of the internal temperature field of the turntable, eliminating the causes of asymmetric thermal deformation from a structural perspective, and effectively improving the turntable's accuracy retention and operational stability.

[0069] This invention also discloses a high-precision temperature control method for a turntable, used to control a high-precision temperature control turntable device and regulate the temperature inside the turntable, comprising the following steps:

[0070] S1. Temperature data of various areas inside the turntable are collected in real time by temperature acquisition devices 12 arranged on the outer wall of base B4, the inner wall of base C5, and base D6. At the same time, the real-time power, current, speed, and load operating parameters of the three-phase DD motor 10 are collected. The total heat generation power of the turntable is calculated based on the operating parameters. The formula for calculating the total heat generation power is: ;

[0071] in, The rated heating power of the three-phase DD motor 10 The power of frictional heat generation in the sealing component. This refers to the standby heat generation power of the hydraulic system.

[0072] S2. Three-level cooling coordinated control is adopted: water cooling control is performed through the double-layer motor stator water jacket 11 and water cooling cavity 24 outside the three-phase DD motor 10; lubrication and cooling control of roller bearing 14 is performed through oil cooling cavity 25; and forced air cooling control is performed through the annular air cooling channel composed of inner air cooling copper pipe 20 and outer air cooling copper pipe 17.

[0073] S3. It adopts a water-cooling control architecture with a main loop-secondary loop dual closed loop and flow feedforward, and performs water-cooling and air-cooling linkage control.

[0074] S4. Dynamically adjust the cooling control threshold based on the turntable operating conditions and data from each temperature acquisition device 12, and execute anti-shake switching control.

[0075] S5. Implement graded fault-tolerant control for temperature acquisition device 12 and cooling circuit failures. At the same time, calculate the thermal deformation based on the temperature acquisition data and input it into the CNC system to perform real-time thermal error compensation.

[0076] The dynamic threshold adjustment and anti-shake control rules are as follows: the hysteresis range of the internal cavity high temperature protection trigger threshold and recovery threshold is set to 3~5℃. When the temperature acquisition device 12 on the outer wall of the base B4 detects that the temperature of the roller bearing 14 is higher than 45℃, the high temperature trigger threshold is adjusted to 55℃.

[0077] When the ambient temperature is higher than 35℃, the high temperature trigger threshold is increased by 2~3℃; the high temperature protection logic is disabled for the first 2 minutes after the turntable starts to avoid false triggering.

[0078] The allowable temperature rise range under different operating conditions is as follows: 2~4℃ for low-speed / intermittent operation, 4~6℃ for medium-speed / continuous operation, 7~9℃ for high-speed / heavy-load operation, and ≤2℃ for high-precision machining.

[0079] The control logic for step S5 is as follows:

[0080] During the fault-tolerant control phase, when a single-channel temperature acquisition device 12 fails, the data is switched to the redundant temperature acquisition device 12 at the same location. If there is no redundant acquisition device, the pre-trained heat conduction model is called to estimate the temperature at the corresponding location to maintain operation.

[0081] When a single cooling circuit failure is detected, the operating power of the remaining normal cooling circuits is increased while the turntable is derated; when all cooling circuits fail or the temperature exceeds the maximum safety threshold, an emergency shutdown is triggered.

[0082] During the thermal error compensation stage, the collected data from the temperature acquisition device 12 is input into the pre-trained thermal deformation prediction model, and the axial and radial thermal deformation of the worktable 2 is output. The deformation is then used as a compensation value and input into the CNC system to correct the machining coordinates.

[0083] In one embodiment, refer to Figure 8As can be seen, after the turntable starts and enters the operating state, the first step is to perform parameter acquisition and heat generation prediction. Six circumferentially evenly distributed temperature acquisition devices 12 located on the outer wall of base B4, six circumferentially evenly distributed temperature acquisition devices 12 located on the inner wall of base C5, and six circumferentially evenly distributed temperature acquisition devices 12 located directly above the outer layer of the air-cooled copper pipe 17 on base D6 simultaneously start sampling, acquiring real-time temperature data for the roller bearing 14 area, the stator area of ​​the three-phase DD motor 10, and the air area inside the turntable cavity, respectively. The sampling data from all temperature acquisition devices 12 is transmitted in real-time to the turntable CNC system through the junction box 13 fixed to the outer wall of base D6. Simultaneously, the CNC system synchronously obtains the real-time power, current, speed, and load operating parameters of the three-phase DD motor 10 from the servo drive unit, and calls the pre-stored total heat generation power calculation formula. ;

[0084] in, The rated heating power of the three-phase DD motor 10 The power of frictional heat generation in the sealing component. This refers to the standby heat generation power of the hydraulic system.

[0085] After accurately predicting the heat source's heat output, the system executes a three-level cooling coordinated control procedure: Based on the calculated total heat output and the matching relationship with the preset threshold, the oil cooling control circuit is first activated, allowing the cooling lubricating oil to continuously circulate within the oil cooling channel 25 surrounding the outer ring of the roller bearing 14, simultaneously completing the lubrication and frictional heat removal of the roller bearing 14. When the total heat output reaches the water cooling start-up threshold, the water cooling control circuit is activated simultaneously. The cooling water output from the external water chiller first flows into the double-layer spiral surrounding motor stator water jacket 11, which is fitted outside the three-phase DD motor 10, and performs efficient heat exchange with the stator. After the core heat generated by the motor is removed, it flows into the water-cooled cavity 24 between the three-phase DD motor 10 and the roller bearing 14, further removing the conductive heat inside the turntable before flowing back to the external water chiller to complete the cycle. When the total heat generation power reaches the air-cooling start-up threshold, the forced air-cooling control circuit is started simultaneously. Compressed refrigerated air is introduced into the annular air-cooling channel formed by the inner air-cooling copper pipe 20 and the outer air-cooling copper pipe 17 spliced ​​together by the T-connector 21, which forcibly discharges the heat accumulated in the turntable cavity, realizing the coordinated cooperation of the three cooling methods and ensuring the uniformity and stability of the internal temperature field of the turntable under all working conditions.

[0086] In one embodiment, refer to Figure 9 , Figure 10 , Figure 11 and Figure 12 It can be seen that the water-cooling and air-cooling coordinated control process is implemented as follows: After the turntable starts, the parameter acquisition step is executed first, and the temperature of the roller bearing 14 is collected by the temperature acquisition device 12 arranged on the outer wall of the base B4. Temperature acquisition device 12, located on the inner wall of base C5, collects the stator temperature of three-phase DD motor 10. Simultaneous collection of ambient temperature And the real-time power, current, speed, and load operating parameters of the three-phase DD motor 10, and the total heat generation power formula. Calculate the total heat generation of the turntable, and then use the formula for minimum water cooling flow rate. Minimum airflow formula for air-cooled systems Calculate the minimum supply of the corresponding cooling medium, where, The specific heat capacity of cooling water, For the density of cooling water, To preset the allowable temperature rise, Assuming a temperature rise, the selected water chiller must meet the following requirements: cooling capacity ≥ 27.2KW and cooling flow rate ≥ 48.6L / min; The specific heat capacity of air, The air density is then used; subsequently, the mode selection phase begins, if the stator temperature... If the temperature exceeds the 50℃ safety threshold, it enters the cavity priority mode, with 45℃ as the PID setpoint. The cooling output is adjusted to regulate process variables; under normal operating conditions, it enters a bearing-following mode with environmental compensation. The cooling output is adjusted by setting the PID setpoint and the bearing temperature Tb as process variables. The PID calculation outputs a 4-20mA signal to the frequency converter to adjust the fan speed and cooling medium flow rate accordingly. After each round of adjustment, there is a 5-10 second delay before entering the next round of data acquisition to avoid frequent adjustments caused by the lag in temperature changes.

[0087] The water-cooling control system employs a dual closed-loop architecture with a main loop and a secondary loop, plus a flow feedforward structure. The main loop calculates the optimal inlet water temperature setpoint for the water-cooling system based on the measured stator temperature Tc and the preset target temperature. The secondary loop uses the difference between the measured temperature and the inlet water temperature setpoint collected by the water chiller outlet temperature collector 12 to adjust the compressor frequency and heater duty cycle of the water chiller using PID control, thereby stabilizing the outlet temperature within the setpoint ±0.5℃ range. The flow feedforward module calculates the heat generation increment based on the real-time power / current of the three-phase DD motor 10, matches the corresponding cooling water flow increment, and adds it to the flow PID setpoint, thus adjusting the cooling water flow in the water-cooling cavity 24 and the motor stator water jacket 11 in advance. This solves the technical problems of high lag and large temperature fluctuation in traditional water-cooling control, significantly improving the accuracy of water-cooling temperature control.

[0088] During the cooling mode tiered switching phase, when the stator temperature Tc is detected to be higher than the water cooling trigger threshold (i.e., 5°C lower than the ambient temperature), only the water cooling circuit and the oil cooling circuit of the oil cooling cavity 25 are activated to prioritize the basic heat dissipation of the core heat source. When the stator temperature Tc is detected to further rise to higher than the air cooling trigger threshold (i.e., 2°C lower than the ambient temperature), the annular air cooling channel composed of the inner air cooling copper pipe 20 and the outer air cooling copper pipe 17 is activated simultaneously. The cold air flows out through the air outlet 22 and is then diverted by the shielding cover 23 to evenly cover the surface of the stator and roller bearing 14 of the three-phase DD motor 10, avoiding non-uniform thermal deformation caused by local direct blowing. This solves the problem of hysteresis and frequent switching in traditional cooling mode switching logic. To address the issue of temperature fluctuations, dynamic threshold adjustment and anti-shake control are implemented synchronously during operation. The hysteresis range between the internal high-temperature protection trigger threshold and the recovery threshold is set to 3~5℃. When the temperature of roller bearing 14 exceeds 45℃, the high-temperature trigger threshold is increased to 55℃. When the ambient temperature exceeds 35℃, the high-temperature trigger threshold is increased by 2~3℃. The high-temperature protection logic is disabled for the first 2 minutes after the turntable starts to avoid false triggering. At the same time, the allowable temperature rise range is set to adapt to different working conditions: 2~4℃ for low-speed / intermittent operation, 4~6℃ for medium-speed / continuous operation, 7~9℃ for high-speed / heavy-load operation, and ≤2℃ for high-precision machining, achieving the optimal balance between cooling energy consumption and control accuracy.

[0089] During the fault handling phase, hierarchical fault-tolerant control is implemented. When a single-channel temperature acquisition device 12 fails, the data is switched to the redundant temperature acquisition device 12 at the same location. If there is no redundant acquisition device, the pre-trained heat conduction model is called to estimate the temperature at the corresponding location to maintain operation. When a single-channel cooling circuit fails, the operating power of the remaining normal cooling circuits is increased while the turntable is derated. When all cooling circuits fail or the temperature exceeds the maximum safety threshold, an emergency shutdown is triggered. At the same time, the temperature acquisition data is input into the pre-trained thermal deformation prediction model, and the axial and radial thermal deformation of the worktable 2 is output. The deformation is used as a compensation value and input into the CNC system to correct the machining coordinates, thereby reducing the probability of unnecessary shutdowns and further offsetting residual thermal deformation.

[0090] Through this control logic, the thermal analysis cloud map shows that the maximum temperature difference in the stator and bearing core area inside the turntable can be controlled within 1℃, and the overall temperature rise of the turntable can be stably controlled within 2℃. This effectively achieves high-precision temperature control of the turntable under all working conditions, which can improve the rotational accuracy of the turntable by more than 40% and extend the service life of the core moving parts.

[0091] In one embodiment, refer to Figure 8 and Figure 9 It can be seen that during operation, the main heat sources inside the turntable include the three-phase DD motor 10, bearing rolling friction, hydraulic system, sealing friction, and changes in external ambient temperature.

[0092] Total heat generation power calculation:

[0093] ;

[0094] in, This refers to the heating power of the three-phase DD motor 10; Friction for the seal; The hydraulic system generates heat during standby. Total heating power (KW);

[0095] If the heat removed by the cooling capacity is equal to the total heat generation power, then the minimum cooling flow rate is:

[0096] ;

[0097] in, The specific heat capacity of the cooling water is taken as 4.2 kJ / (kg·K); The density of the cooling water is 1000 kg / m³. The minimum cooling water flow rate required for the three-phase DD motor 10; Assuming a temperature rise of 8°C;

[0098] Based on the calculations above, a water chiller with a cooling capacity of 27.2KW or higher, a cooling flow rate of 48.6L / min or higher, a cooling power of 30KW, and a cooling flow rate of 120L / min should be selected to meet the usage requirements.

[0099] The guaranteed temperature rise at this time is:

[0100] ;

[0101] Among them, the heat generation calculation of the three-phase DD motor 10 is as follows:

[0102] ;

[0103] Bearing heat generation calculation:

[0104] ;

[0105] in, For the cooling efficiency of the bearing and DD motor, we take 0.1; The heating power of crossed roller bearings;

[0106] Other heat sources include: hydraulic brakes: approximately 0.1 kW of heat generated during standby; sealing friction: approximately 0.05 kW;

[0107] Steady-state thermal analysis was performed using the finite element method: Three-phase DD motor 10: Surface heat dissipation 1.49 kW, uniformly distributed; Crossed tapered roller bearing: Surface heat dissipation 0.435 kW, uniformly distributed; External surface natural convection: h = 5 W / (m²·K), T = 25°C; Base and foundation conduction: h = 5 W / (m²·K), T = 25°C; Internal forced air convection: h = 5 W / (m²·K), T = 25°C

[0108] The specific results of the temperature field analysis are as follows:

[0109]

[0110] Maximum temperature rise: Bearing temperature rise: Countertop temperature rise: average Countertop temperature gradient: The temperature difference between the center and edge of the countertop is 2.7°C.

[0111] The steady-state temperature field is applied as a thermal load to the structural model for thermal deformation analysis.

[0112] 1) Axial thermal deformation

[0113]

[0114] 2) Radial thermal deformation

[0115]

[0116] The axial deformation of the center and edge of the worktable 2 is 0.027mm, and the radial thermal deformation caused by the worktable 2 is 0.026mm. Although the error caused by thermal deformation is small, effective thermal error control must be implemented. When the temperature changes significantly, cooling measures need to be improved.

[0117] Temperature control is achieved through a three-stage integrated control system. The first stage is active cooling, specifically cooling of the three-phase DD motor 10: spiral water channel cooling for the casing, forced water cooling at a flow rate of 120 L / min; and bearing cooling: lubrication and cooling with lubricating oil at a flow rate of 24 L / min. The second stage is a thermally symmetrical design, with symmetrical heat dissipation structures and cooling pipes, and key components made of low-expansion materials. The third stage is online temperature monitoring.

[0118] Temperature sensors are arranged, with at least 6 temperature acquisition devices 12 arranged on the outer wall of base B4 and the inner wall of base C5, and at least 6 temperature acquisition devices 12 arranged directly above the outer layer of air-cooled copper pipe 17 on base D6, in close contact with the metal surface. Through the above three-level integrated control strategy, when temperature difference fluctuations are detected, active cooling (water chiller flow rate, pressure, internal forced air cooling flow rate, etc. to enhance cooling of various parts) is improved, which can reduce thermal error by more than 96% and meet the accuracy requirements.

[0119] Working principle: The concentrically arranged bases A3, B4, C5, and D6, integrally formed inside the turntable base 1, provide a high coaxiality mounting reference for all moving parts. The three-phase DD motor 10 outputs torque to drive the central rotating shaft 9 to rotate, which in turn drives the flange connecting plate 7 mounted on the central rotating cylinder 8 to complete the rotational motion of the worktable 2. During operation, the friction of the stator of the three-phase DD motor 10, the roller bearing 14 mounted on the outer wall of the base C5, and the friction of the seals are the core heat sources. Cooling is first introduced through the double-layer spiral motor water jacket 11 surrounding the three-phase DD motor 10. Water carries away the heat generated by the motor core. The water flows into the water-cooling cavity 24 between the three-phase DD motor 10 and the roller bearing 14 to further dissipate the conductive heat and complete the water-cooling cycle. At the same time, the circulating lubricating oil in the oil-cooling cavity 25 between the base D6 and the roller bearing 14, which surrounds the outer ring of the roller bearing 14, simultaneously completes bearing lubrication and frictional heat dissipation. When the temperature reaches the air-cooling trigger threshold, the inner air-cooling copper pipe 20 and the outer air-cooling copper pipe 17, which are respectively fixed to the brake flange 18 on the top of the base A3 and the mounting seat 15 on the inner wall of the base C5, are activated by the L-shaped mounting plate 16 and the three-way connector 21. Compressed cold air is introduced into the annular air-cooling channel. After flowing out through the air outlet 22 at the outlet end of the three-way connector 21, the cold air is split by the shielding cover 23, evenly covering the surface of the stator and bearing, and carrying away the heat accumulated in the inner cavity. The hot air after heat exchange is discharged through the heat dissipation holes 26 on the integrated layered base plate 27 at the bottom of the turntable base 1. Multiple sets of temperature acquisition devices 12 arranged on the outer wall of base B4, the inner wall of base C5, and directly above the outer layer of air-cooling copper pipe 17 on base D6 collect temperature data of each area in real time. The data is transmitted to the turntable CNC system through the junction box 13 on the outer wall of base D6. The system combines the collected temperature data... The total heat generation power is calculated based on the real-time operating parameters of the three-phase DD motor 10. Through main and auxiliary dual closed-loop water cooling control with flow feedforward, graded linkage air cooling control, dynamic threshold anti-shake control and graded fault-tolerant compensation logic, the operating parameters of each cooling circuit are dynamically adjusted. The collected temperature data is simultaneously input into the pre-trained thermal deformation prediction model to calculate the axial and radial thermal deformation of the worktable 2 and input into the CNC system to complete the machining coordinate compensation. Asymmetric thermal deformation is suppressed from three dimensions: structural accuracy maintenance, active uniform heat dissipation and residual error compensation, so as to achieve high-precision and stable operation of the turntable under all working conditions.

[0120] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various equivalent changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-precision temperature control turntable device, characterized in that, It includes a turntable base (1) and a worktable (2). The turntable base (1) has an integrally formed concentric structure. From the inside to the outside, base A (3), base B (4), base C (5) and base D (6) are arranged in sequence. The worktable (2) is connected to a three-phase DD motor (10) installed inside the turntable base (1) through a transmission assembly. The turntable base (1) is equipped with a three-stage cooling system: the three-phase DD motor (10) is fitted with at least two layers of motor stator water jackets (11), the outer ring of the roller bearing (14) is provided with an oil cooling cavity (25), and the turntable base (1) is also provided with an annular air cooling channel composed of an inner layer air-cooled copper pipe (20) and an outer layer air-cooled copper pipe (17) that are interconnected. Multiple temperature acquisition devices (12) are arranged in the circumferential direction inside the turntable base (1), and heat dissipation holes (26) are opened at the bottom of the turntable base (1).

2. The high-precision temperature control turntable device according to claim 1, characterized in that, The two-layer motor stator water jacket (11) outside the three-phase DD motor (10) is a spiral-wound water channel structure. The inlet of the motor stator water jacket (11) is connected to the outlet of the external water chiller. The outlet of the motor stator water jacket (11) is connected to the inlet of the water cooling cavity (24) set between the three-phase DD motor (10) and the roller bearing (14). The water outlet of the water cooling cavity (24) flows back to the external water chiller. The oil cooling channel (25) is arranged around the outer ring of the roller bearing (14) for lubricating and cooling the roller bearing (14); The bottom of the turntable base (1) is an integrally formed layered base plate (27), with heat dissipation holes (26) arranged in a staggered manner on the upper and lower base plates.

3. The high-precision temperature control turntable device according to claim 1, characterized in that, At least 18 temperature acquisition devices (12) are provided, with at least 6 temperature acquisition devices (12) arranged on the outer wall of base B (4) and the inner wall of base C (5), and at least 6 temperature acquisition devices (12) arranged on base D (6) directly above the outer air-cooled copper pipe (17). All temperature acquisition devices (12) communicate with the turntable CNC system in real time through the junction box (13) provided on the outer wall of base D (6).

4. The high-precision temperature control turntable device according to claim 1, characterized in that, The inner air-cooled copper tube (20) and the outer air-cooled copper tube (17) are both made of copper tubes. The inner air-cooled copper tube (20) is arranged around the top of the stator of the three-phase DD motor (10) in a circumferential manner, and the outer air-cooled copper tube (17) is arranged around the inner wall of the base D (6) in a circumferential manner. The inner wall of the base C (5) is provided with a mounting seat (15) with an opening facing the central rotating shaft (9). The top of the base A (3) is provided with a brake flange (18) fitted on the central rotating cylinder (8). The mounting seat (15) and the brake flange (18) are both fixed with L-shaped mounting plates (16) by bolts (19). The inner air-cooled copper tube (20) and the outer air-cooled copper tube (17) are fixed to the horizontal side of the corresponding L-shaped mounting plate (16) by a three-way connector (21).

5. The high-precision temperature control turntable device according to claim 1, characterized in that, At least four evenly arranged air outlets (22) are provided on the inner air-cooled copper tube (20) and the outer air-cooled copper tube (17). The air outlets (22) are fitted onto the outlet end of the three-way connector (21), and the air outlet direction is towards the gap between the stator and the roller bearing (14) of the three-phase DD motor (10). A shielding cover (23) is fixed on the outlet end of the three-way connector (21). The distance between the shielding cover (23) and the outlet end is 3~5mm. After being blocked by the shielding cover (23), the cold air is split radially to both sides, evenly covering the surface of the stator of the three-phase DD motor (10) and the outer ring of the roller bearing (14).

6. A high-precision temperature control method for a temperature-controlled turntable, characterized in that, The high-precision temperature control turntable device according to claims 1-5 is used to regulate the temperature inside the turntable, comprising the following steps: S1. Temperature data of each area inside the turntable is collected in real time by temperature acquisition devices (12) arranged on the outer wall of base B (4), the inner wall of base C (5), and base D (6). At the same time, the real-time power, current, speed, and load operating parameters of the three-phase DD motor (10) are collected. The total heat generation power of the turntable is calculated based on the operating parameters. The formula for calculating the total heat generation power is: ; in, The rated heating power of the three-phase DD motor (10) is... The power of frictional heat generation in the sealing component. This refers to the standby heat generation power of the hydraulic system. S2. Three-level cooling coordinated control is adopted: water cooling control is performed through the double-layer motor stator water jacket (11) and water cooling cavity (24) outside the three-phase DD motor (10), lubrication and cooling control of roller bearing (14) is performed through oil cooling cavity (25), and forced air cooling control is performed through the annular air cooling channel composed of inner air cooling copper pipe (20) and outer air cooling copper pipe (17). S3. It adopts a water-cooling control architecture with a main loop-secondary loop dual closed loop and flow feedforward, and performs water-cooling and air-cooling linkage control. S4. Combine the turntable operating conditions with the data from each temperature acquisition unit (12) to dynamically adjust the cooling control threshold and perform anti-shake switching control; S5. For temperature acquisition device (12) and cooling circuit failure, perform graded fault-tolerant control, and calculate thermal deformation based on temperature acquisition data, and input it into the CNC system to perform real-time thermal error compensation.

7. The temperature control method according to claim 6, characterized in that, The water cooling control in step S3 specifically involves: The main circuit collects the measured temperature of the stator of the three-phase DD motor (10) and the preset target temperature through the temperature acquisition device (12) on the inner wall of the base C (5) to calculate the optimal inlet water temperature setting value of the water cooling system. The difference between the measured temperature and the set value of the inlet water temperature is collected by the water chiller outlet temperature acquisition device (12) in the secondary circuit. The PID adjusts the compressor frequency and heater duty cycle of the water chiller so that the outlet temperature is stable within the range of ±0.5℃ of the set value. The flow feedforward module calculates the heat generation increment based on the real-time power / current of the three-phase DD motor (10), matches the corresponding cooling water flow increment and adds it to the flow PID setting value, and adjusts the cooling water flow in the water cooling cavity (24) and the motor stator water jacket (11) in advance.

8. The temperature control method according to claim 6, characterized in that, The water-cooling and air-cooling linkage control logic in step S3 is as follows: When the temperature acquisition device (12) on the inner wall of the base C (5) detects that the stator temperature of the three-phase DD motor (10) is higher than the water cooling trigger threshold, that is, 5°C lower than the ambient temperature, only water cooling and oil cooling control will be activated. When the temperature of the stator of the three-phase DD motor (10) is detected to be higher than the air-cooling trigger threshold, that is, 2°C lower than the ambient temperature, the annular air-cooling channel is activated at the same time. The air outlets (22) of the inner and outer air-cooling copper tubes (17) are split by the shielding cover (23) and output cold air to cover the surface of the stator and roller bearing (14) of the three-phase DD motor (10) to avoid non-uniform thermal deformation caused by local direct blowing. The formula for calculating the minimum cooling flow rate of a water-cooled system is: ; in, The specific heat capacity of cooling water, For the density of cooling water, To ensure the preset allowable temperature rise, the selected water chiller must meet the following requirements: cooling capacity ≥ 27.2KW and cooling flow rate ≥ 48.6L / min; The formula for calculating the minimum airflow of an air-cooled system is: ; in, The specific heat capacity of air, air density; This assumes a temperature rise.

9. The temperature control method according to claim 6, characterized in that, The dynamic threshold adjustment and anti-shake control rules in step S4 are as follows: the hysteresis range of the inner cavity high temperature protection trigger threshold and the recovery threshold is set to 3~5℃. When the temperature acquisition device (12) of the outer wall of the base B (4) detects that the temperature of the roller bearing (14) is higher than 45℃, the high temperature trigger threshold is adjusted to 55℃. When the ambient temperature is higher than 35℃, the high temperature trigger threshold is increased by 2~3℃; the high temperature protection logic is disabled for the first 2 minutes after the turntable starts to avoid false triggering. The allowable temperature rise range under different operating conditions is as follows: 2~4℃ for low-speed / intermittent operation, 4~6℃ for medium-speed / continuous operation, 7~9℃ for high-speed / heavy-load operation, and ≤2℃ for high-precision machining.

10. The temperature control method according to claim 6, characterized in that, The control logic for step S5 is as follows: During the fault-tolerant control phase, when a single-channel temperature acquisition device (12) is detected to be in failure, the data is switched to the redundant temperature acquisition device (12) at the same location. If there is no redundant acquisition device, the pre-trained heat conduction model is called to estimate the temperature at the corresponding location to maintain operation. When a single cooling circuit failure is detected, the operating power of the remaining normal cooling circuits is increased while the turntable is derated; when all cooling circuits fail or the temperature exceeds the maximum safety threshold, an emergency shutdown is triggered. In the thermal error compensation stage, the collected data from the temperature acquisition device (12) is input into the pre-trained thermal deformation prediction model, and the axial and radial thermal deformation of the worktable (2) is output. The deformation is used as the compensation value and input into the CNC system to correct the machining coordinates.

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