Intelligent monitoring, regulating and controlling system and control method for motorized spindle

Abstract

The invention relates to the technical field of motorized spindles, in particular to an intelligent monitoring, regulating and controlling system and a control method of a motorized spindle. A first front-end displacement sensor and a second front-end displacement sensor are used for detecting the displacement amount of a front-end bearing in the X direction and the Y direction respectively, and a first rear-end displacement sensor is used for detecting the displacement amount of a rear-end bearing in the Z direction; when the displacement of the front-end bearing in the X direction and the Y direction or the displacement of the rear-end bearing in the Z direction exceeds a set threshold value, the signal acquisition control system controls the piezoelectric ceramic sensor to act so as to adjust the pre-tightening force of the motorized spindle, and when the temperature detected by the temperature sensor exceeds the set threshold value, the water cooling system is started for cooling, and when the temperature still exceeds the set threshold value, the motor is started. According to the electric spindle cooling system, accurate control over the cooling effect of the electric spindle is achieved through combination of water cooling and oil cooling.

Description

Technical Field

[0001] The present invention relates to the technical field of electric spindles, and in particular to an intelligent monitoring and control system and a control method for an electric spindle. Background Art

[0002] With the rapid development of industrial intelligence, CNC machine tools are more and more widely used in industrial development. As the core component of CNC machine tools, the operating status of the electric spindle determines the working performance of the CNC machine tools. At present, most of the operating status of the electric spindle is measured based on the batch qualification rate of product processing or the vibration and noise changes of the machine tools during the working process, and the changes in the working performance of the electric spindle cannot be accurately predicted. In addition, since the electric spindle generates heat during operation, the change of this heat will cause thermal deformation of key components of the electric spindle such as bearings and shafts. This thermal deformation seriously affects the machining accuracy of the machine tool and the service life of the bearings.

[0003] Therefore, realizing intelligent control and intelligent monitoring of the electric spindle is an effective way to accurately predict the working performance of the electric spindle. At the same time, the intelligent regulation of the temperature and displacement of the electric spindle is an effective way to reduce the impact of the temperature change of the electric spindle on the accuracy of the electric spindle. It is of great significance to realize intelligent control and status monitoring of the electric spindle. Since the outer shell of the electric spindle is a cooling system, as well as the gradient of the bearing temperature change and the integrity and sealing of the bearing seat structure, it is difficult to accurately monitor the bearing temperature. At present, the temperature rise change of the general electric spindle can only be cooled by water cooling or oil mist, and the controllability of the cooling effect is not enough, which will affect its performance and service life.

[0004] In summary, there are still many deficiencies in the current monitoring of temperature, displacement and vibration during the operation of the electric spindle, as well as preload compensation and temperature control. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, an object of the present invention is to provide an intelligent monitoring and control system and control method for an electric spindle, aiming to solve the problem that the existing electric spindle is unable to monitor and control its own performance.

[0006] The technical solution of the present invention is:

[0007] An intelligent monitoring and control system for an electric spindle includes an electric spindle rotor assembly, an electric spindle stator assembly, a temperature control assembly, and a temperature proportional controller.

[0008] An electric spindle stator assembly and an electric spindle housing are sequentially arranged on the outer side of the electric spindle rotor assembly, and a plurality of temperature sensors are evenly distributed on the outer sides of the front end bearing and the rear end bearing of the electric spindle rotor assembly;

[0009] The temperature control component includes a water cooling control component and an oil cooling control component. The water cooling control component is connected to the cold water channel on the electric spindle housing through a pipeline, and the water cooling control component is used to cool the electric spindle rotor component and the electric spindle stator component. The oil cooling control component is connected to the oil cooling channel on the electric spindle housing through a pipeline, and the oil cooling control component is used to cool the electric spindle rotor component and the electric spindle stator component.

[0010] The temperature sensor, water cooling control component, and oil cooling control component are connected to the temperature proportional controller. The temperature value collected by the temperature sensor is transmitted to the temperature proportional controller. The temperature proportional controller determines that the collected temperature information exceeds the set temperature threshold. The temperature proportional controller controls the water cooling control component to work and continues for a preset time period. If the temperature value collected by the temperature sensor is less than the set temperature threshold, the water cooling control component stops working; if the water cooling control component continues to work for a preset time period, the temperature value collected by the temperature sensor is still greater than the set temperature threshold, and the duration reaches the preset time period, the temperature proportional controller controls the oil cooling control component to work until the temperature value collected by the temperature sensor is less than the set temperature threshold.

[0011] The water cooling control component includes a water pump, a cooling fan, and a water pipe. The water inlet of the water pump is connected to the water tank, and the water outlet of the water pump is connected to the water storage tank. A cooling fan is provided on one side of the water storage tank. The cooling fan is driven by a fan motor. The cooling fan cools the water in the water storage tank. The water outlet of the water storage tank is connected to the water inlet of the cold water channel through a pipe joint, and the water outlet of the cold water channel is connected to the water tank;

[0012] The temperature proportional controller is connected to the fan motor. The temperature proportional controller determines that the temperature information collected by the temperature sensor exceeds the set temperature threshold. The temperature proportional controller controls the fan motor to start and adjusts the fan motor power to adjust the cooling fan speed. If the cooling fan speed is modulated to the maximum limit and continues for a preset time period, the temperature value collected by the temperature sensor is less than the set temperature threshold, the oil cooling control component is started.

[0013] The oil cooling control assembly includes an oil mist system, an oil mist device, an oil mist flow control valve, and an oil pipe. The oil mist system is connected to the oil inlet of the oil cooling channel through a pipeline. The oil mist flow control valve and the oil mist device are arranged on the pipeline. The oil outlet of the oil cooling channel is connected to the oil mist system.

[0014] The temperature proportional controller is connected to the oil mist flow control valve. When the water cooling component is working, the temperature proportional controller determines that the temperature information collected by the temperature sensor still exceeds the set temperature threshold. The temperature proportional controller controls the oil mist flow control valve switch and flow rate to cool down the electric spindle rotor assembly and the electric spindle stator assembly.

[0015] An intelligent monitoring and control system for an electric spindle also includes a signal acquisition and control system. Vibration sensors are respectively provided on the outside of the front end bearing and the rear end bearing of the electric spindle rotor assembly. The vibration sensors collect vibration information of the front end bearing and the rear end bearing, and transmit the vibration information to the signal acquisition and control system. The signal acquisition and control system determines the performance of the front end bearing and the rear end bearing based on the vibration information.

[0016] The front end of the electric spindle rotor assembly is connected to a first front end displacement sensor and a second front end displacement sensor through a displacement sensor fixing frame, wherein the first front end displacement sensor is used to detect the displacement of the front end bearing of the electric spindle rotor assembly in the Y direction, and the second front end displacement sensor is used to detect the displacement of the front end bearing of the electric spindle rotor assembly in the X direction;

[0017] The rear end of the electric spindle rotor assembly is connected to a first rear end displacement sensor through a rear end cover, and the first rear end displacement sensor is used to detect the displacement of the rear end bearing of the electric spindle rotor assembly in the Z direction;

[0018] An adjustable preload component is provided at the rear end of the electric spindle rotor assembly, and the adjustable preload component is fixed on the electric spindle rotor assembly through a rear bearing seat. The adjustable preload component includes a piezoelectric ceramic front holding structure, a piezoelectric ceramic rear supporting structure, and a piezoelectric ceramic sensor. The piezoelectric ceramic front holding structure and the piezoelectric ceramic rear supporting structure are respectively fixed on the rear bearing seat, and the piezoelectric ceramic sensor is placed between the piezoelectric ceramic front holding structure and the piezoelectric ceramic rear supporting structure.

[0019] The displacement value information of the first front-end displacement sensor, the second front-end displacement sensor, and the first rear-end displacement sensor is transmitted to the signal acquisition control system, and the signal acquisition control system controls the piezoelectric ceramic sensor to adjust the preload force.

[0020] A control method for an intelligent monitoring and control system of an electric spindle comprises the following steps:

[0021] Step 1: The electric spindle is running, the temperature sensor detects the real-time temperature values ​​of the front-end bearing and the rear-end bearing, the first front-end displacement sensor and the second front-end displacement sensor detect the displacement of the front-end bearing in the X and Y directions respectively, and the first rear-end displacement sensor detects the displacement of the rear-end bearing in the Z direction;

[0022] Step 2: When the displacement of the front end bearing in the X and Y directions or the displacement of the rear end bearing in the Z direction exceeds the set threshold, the signal acquisition control system controls the piezoelectric ceramic sensor to adjust the preload force of the electric spindle;

[0023] Step 3: When the temperature detected by the temperature sensor exceeds the set threshold, the temperature proportional controller controls the cooling fan to start. At the same time, according to the temperature of the front end bearing or the rear end bearing detected by the temperature sensor, the power of the cooling fan is adjusted. The cooling water circulates in the water cooling channel to cool down the electric spindle rotor assembly and the electric spindle stator assembly. After a preset period of time, when the temperature detected by the temperature sensor is lower than the set threshold, the cooling fan stops working. When the cooling fan stops working, if the temperature detected by the temperature sensor is still higher than the set threshold, the temperature proportional controller controls the oil mist flow control valve to work, thereby reducing the temperature of the electric spindle rotor assembly and the electric spindle stator assembly.

[0024] The beneficial effects of adopting the above technical solution are:

[0025] 1. Accurate prediction and real-time monitoring: The present invention can monitor the vibration, preload, displacement, temperature and other key parameters of the electric spindle in real time, and accurately predict the changes in the working performance of the electric spindle. This can not only detect potential faults in time, but also take measures in advance to avoid production interruptions caused by sudden faults, significantly improving production efficiency and equipment reliability.

[0026] 2. Optimize thermal management strategy: In view of the heat generated during the operation of the electric spindle and its impact on the thermal deformation of key components, the present invention has broken through the difficulty of accurately monitoring the bearing temperature in traditional methods through innovative temperature monitoring technology. By real-time monitoring of the temperature changes of the bearing and the surrounding environment, the operation strategy of the cooling system is optimized to ensure that the electric spindle operates within the optimal temperature range, effectively reduce thermal deformation, and improve machine tool processing accuracy and bearing service life.

[0027] 3. Improve the controllability of cooling effect: In view of the problem that the existing cooling method has uncontrollable effect, the present invention combines water cooling and oil cooling to reduce temperature, and dynamically adjusts the parameters of the water cooling control component to achieve precise control of the cooling effect. This can not only improve cooling efficiency, but also reduce energy waste and reduce operating costs.

[0028] 4. Improve overall processing quality and economic benefits: By accurately monitoring and predicting the working status of the electric spindle, and timely discovering and solving potential problems, the present invention can significantly improve the processing accuracy and stability of the machine tool, reduce the defective rate caused by faults, and thus improve the overall processing quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural cross-sectional view of an intelligent monitoring and control system for an electric spindle of the present invention;

[0030] Figure 2 It is a schematic diagram of a water cooling control component of an intelligent monitoring and control system for an electric spindle of the present invention;

[0031] Figure 3 It is a schematic diagram of an oil cooling control component of an intelligent monitoring and control system of an electric spindle of the present invention;

[0032] Figure 4 It is a schematic diagram of the position of a displacement sensor of an intelligent monitoring and control system of an electric spindle of the present invention;

[0033] Figure 5 It is a schematic diagram of the positions of temperature sensors and vibration sensors of an intelligent monitoring and control system for an electric spindle of the present invention;

[0034] Figure 6 It is a structural schematic diagram of a front-end bearing seat of an intelligent monitoring and control system for an electric spindle of the present invention;

[0035] Figure 7 It is a schematic diagram of the assembly of a front-end bearing seat of an intelligent monitoring and control system for an electric spindle of the present invention;

[0036] Figure 8 It is a schematic diagram of the position of a piezoelectric ceramic sensor of an intelligent monitoring and control system of an electric spindle of the present invention;

[0037] Fig. 9 It is a control flow chart of an intelligent monitoring and control system of an electric spindle of the present invention;

[0038] In the attached drawings: 1. spindle rotor assembly; 1-1. spindle shaft; 1-2. spindle stator core; 1-3. first spindle core retaining ring; 1-4. second spindle core retaining ring; 1-5. front end bearing; 1-6. rear end bearing; 1-7. bearing retaining ring; 2. spindle stator assembly; 2-1. water cooling jacket; 2-2. spindle stator system; 2-3. spindle stator retaining ring; 3. spindle housing; 4. front end bearing seat; 4-1. front bearing seat base; 4-2. front bearing seat bearing support; 4-3. front bearing seat bearing adjustment ring; 4-4. tapered slider; 4-5. bolt; 5. front bearing seat sealing end cover; 6. front bearing threaded retaining ring; 7. adjustable preload assembly; 7-1 , piezoelectric ceramic front retaining structure; 7-2, piezoelectric ceramic rear supporting structure; 7-3, piezoelectric ceramic sensor; 8, rear bearing seat; 9, rear end cover; 10, displacement sensor fixing bracket; 11, temperature sensor; 12, water cooling control assembly; 12-1, water pump; 12-2, water storage tank; 12-3, water pipe; 12-4, cooling fan; 13, oil cooling control assembly; 13-1, oil mist system; 13-2, oil mist device; 13-3, oil mist flow control valve; 13-4, oil pipe; 14, temperature proportional controller; 15, signal acquisition control system; 16, vibration sensor; 17, first front end displacement sensor; 18, second front end displacement sensor; 19, first rear end displacement sensor. DETAILED DESCRIPTION

[0039] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0040] The electric spindle is the core component of the machine tool, and the detection and intelligent control of its performance are particularly important. The present invention provides an intelligent monitoring and control system and control method for the electric spindle. The basic idea of ​​the present invention is as follows: by integrating a variety of high-precision sensors with a signal acquisition control system and a temperature proportional controller, the temperature, vibration, preload, displacement and other important performance indicators of the electric spindle are detected in real time, and the temperature control component is used to perform cooling control according to the temperature changes during the operation of the electric spindle, ensuring that the electric spindle operates within the optimal temperature range, effectively reducing thermal deformation, and improving the machine tool processing accuracy and bearing service life.

[0041] like Figure 1-9 As shown, an intelligent monitoring and control system for an electric spindle includes an electric spindle rotor assembly 1, an electric spindle stator assembly 2, a temperature control assembly, and a temperature proportional controller 14.

[0042] The outer side of the electric spindle rotor assembly 1 is sequentially provided with an electric spindle stator assembly 2 and an electric spindle housing 3. A plurality of temperature sensors 11 are evenly distributed on the outer sides of the front bearings 1-5 and the rear bearings 1-6 of the electric spindle rotor assembly 1. In this embodiment, there are three groups of temperature sensors 11, which are respectively arranged on the upper, lower and side sides of the bearings.

[0043] The temperature control component includes a water cooling control component 12 and an oil cooling control component 13. The water cooling control component 12 is connected to the cold water channel on the electric spindle housing 3 through a pipeline, and the water cooling control component is used to cool the electric spindle rotor component 1 and the electric spindle stator component 2. The oil cooling control component 13 is connected to the oil cooling channel on the electric spindle housing 3 through a pipeline, and the oil cooling control component is used to cool the electric spindle rotor component 1 and the electric spindle stator component 2.

[0044] The temperature sensor 11, the water cooling control component 12, and the oil cooling control component 13 are connected to the temperature proportional controller 14. The temperature value collected by the temperature sensor 11 is transmitted to the temperature proportional controller 14. The temperature proportional controller 14 determines that the collected temperature information exceeds the set temperature threshold. The temperature proportional controller 14 controls the water cooling control component 12 to work and continues for a preset time period. When the temperature value collected by the temperature sensor 11 is less than the set temperature threshold, the water cooling control component 12 stops working. If the water cooling control component 12 continues to work for a preset time period, the temperature value collected by the temperature sensor 11 is still greater than the set temperature threshold, and the duration reaches the preset time period, the temperature proportional controller 14 controls the oil cooling control component 13 to work until the temperature value collected by the temperature sensor 11 is less than the set temperature threshold.

[0045] The electric spindle rotor assembly includes an electric spindle shaft 1-1, an electric spindle stator core 1-2, a first electric spindle core retaining ring 1-3, a second electric spindle core retaining ring 1-4, a bearing and a bearing retaining ring 1-7. The electric spindle stator core 1-2 is installed on the outside of the electric spindle shaft 1-1. The first electric spindle core retaining ring 1-3 and the second electric spindle core retaining ring 1-4 fix the two sides of the electric spindle stator core 1-2. The bearing 4 includes a front end bearing 1-5 and a rear end bearing 1-6, which are respectively installed on the front end and the rear end of the electric spindle shaft 1-1. The bearing retaining ring 1-7 is respectively arranged on the outside of the front end bearing 1-5 and the rear end bearing 1-6 and fixed on the electric spindle shaft 1-1, and is used for transmission control of the electric spindle.

[0046] Among them, the materials of the front bearing 1-5 and the rear bearing 1-6 used in the electric spindle are all ceramic;

[0047] The electric spindle stator assembly 2 includes a water cooling jacket 2-1, an electric spindle stator system 2-2 and an electric spindle stator retaining ring 2-3; the electric spindle stator system 2-2 is arranged on the outside of the electric spindle stator core 1-2, the electric spindle stator retaining ring 2-3 is installed at both ends of the electric spindle stator system 2-2 and is located on the outside of the electric spindle stator core 1-2, the electric spindle stator system 2-2 and the electric spindle stator retaining ring 2-3 are provided with a water cooling jacket 2-1 on the outside, the water cooling jacket 2-1 is provided with an electric spindle housing 3, the electric spindle housing 3 and the water cooling jacket 2-1 are assembled by interference fit, the electric spindle stator system 2-2 is installed inside the assembled electric spindle housing 3 and the water cooling jacket 2-1, the user protects the internal structure of the electric spindle, generates a magnetic field and energy conversion;

[0048] A front end bearing seat 4 is provided on the outside of the front end bearing 1-5 of the electric spindle rotor assembly 1, one end of the front end bearing seat 4 is fixed to the electric spindle housing 3, and the other end is connected to the front bearing seat sealing end cover 5, the front bearing threaded retaining ring 6 is locked with the electric spindle shaft 1-1 and the front bearing seat sealing end cover 5 through its own external thread, and the outer side of the front bearing seat sealing end cover 5 is fixedly connected to the displacement sensor fixing frame 10; an adjustable preload component 7 is provided at the rear of the rear end bearing 1-6, a rear bearing seat 8 is provided above the rear end bearing 1-6, the rear bearing seat 8 is connected to the electric spindle housing 3, the adjustable preload component 7 is connected to the rear bearing seat 8, and the rear of the rear bearing seat 8 is connected to the rear end cover 9;

[0049] Specifically: the front end bearing seat 4 is connected to the electric spindle housing 3 by threading, the front bearing seat sealing end cover 5 is connected to the front end bearing seat 4 by threading, and the front bearing thread retaining ring 6 is locked with the electric spindle shaft 1-1 by its own external thread;

[0050] The front end bearing seat 4 includes a front bearing seat base 4-1, a front bearing seat bearing support 4-2, a front bearing seat bearing adjustment ring 4-3, a tapered slider 4-4, and a bolt 4-5. The front bearing seat bearing support 4-2 is located above the front bearing seat base 4-1, and the front bearing seat bearing adjustment ring 4-3 is located in the cavity of the front bearing seat bearing support 4-2 and fits therewith; a groove is provided on the front bearing seat bearing support 4-2, and a plurality of tapered sliders 4-4 are provided in the groove, and the tapered slider 4-4 is slidably connected in the groove, and the front bearing seat bearing support 4-2 is connected to the plurality of tapered sliders 4-4 by bolts 4-5, and the front bearing seat bearing support 4-2 is driven to rotate by the tapered slider 4-4, so as to adjust the position of the first sensor hole and collect the temperature of each position on the side of the bearing;

[0051] A first sensor hole is opened at the front end bearing seat 4, and the front end bearing seat 4 is connected to the temperature sensor 11 on the front end bearing through the first sensor hole by using a sensor transmission line to collect the real-time temperature of the bearing. The front end bearing seat 4 is pre-tightened by a central through-hole bolt structure to prevent the temperature sensor from loosening. A second sensor hole is opened at the connection between the rear bearing seat 8 and the electric spindle housing 3, and the rear bearing seat 8 is connected to the temperature sensor 11 on the rear end bearing 1-6 through the second sensor hole by using a sensor line, and is pre-tightened by a central through-hole bolt structure to collect the temperature at each position on the side of the bearing; when the bearing temperature exceeds the set temperature value, the temperature proportional controller 14 controls the water cooling control component 12 and the oil cooling control component 13 to perform self-regulation, and the electric spindle temperature is cooled by increasing the speed of the spindle cooling fan. When the temperature drops to the set value, the spindle cooling fan speed begins to decrease. When the temperature is still higher than the set temperature, the oil cooling control component 13 is used for regulation to achieve intelligent regulation of the internal temperature of the electric spindle;

[0052] The front end bearing seat 4 in this embodiment can change the contact position of the temperature sensor by adjusting the position of the bearing seat bearing adjustment ring 4-3, without the need to replace the front bearing seat 4 or drill holes at the bearing seat measurement point. The position change of the tapered slider 4-4 can measure the position of any point of the outer ring of the bearing within 360°.

[0053] The inner hole of the front bearing seat 4 adopts a through-hole design, the inner shoulder of the front bearing seat is removed, and the front bearing seat sealing end cover 5 is used for axial positioning, so that during the spindle assembly process, the full ceramic bearing can be assembled to the shaft first, and then directly installed at the rear end of the spindle, avoiding the need to first install the shaft on the spindle and then install the bearing. This can facilitate the installation of the front bearing, ensure that the full ceramic is cooled by liquid nitrogen immersion during the installation process, and achieve uniform cooling of the shaft. It is used for the assembly of full ceramic bearings in electric spindles.

[0054] The water cooling control assembly 12 includes a water pump 12-1, a cooling fan 12-4, and a water pipe 12-3. The water inlet of the water pump 12-1 is connected to a water tank, and the water outlet of the water pump 12-1 is connected to a water storage tank 12-2. A cooling fan 12-4 is provided on one side of the water storage tank 12-2. The cooling fan 12-4 is driven by a fan motor. The cooling fan 12-4 cools the water in the water storage tank 12-2. The water outlet of the water storage tank 12-2 is connected to the water inlet of the cold water channel through a pipe joint, and the water outlet of the cold water channel is connected to the water tank;

[0055] The temperature proportional controller is connected to the cooling fan 12-4. The temperature proportional controller 14 determines that the temperature information collected by the temperature sensor 11 exceeds the set temperature threshold. The temperature proportional controller 14 controls the speed of the cooling fan 12-4. If the speed modulation of the cooling fan 12-4 reaches the maximum limit and lasts for a preset time period, and the temperature value collected by the temperature sensor 11 is less than the set temperature threshold, the oil cooling control component 13 is started;

[0056] The oil cooling control assembly 13 includes an oil mist system 13-1, an oil mist device 13-2, an oil mist flow control valve 13-3, and an oil pipe 13-4. The oil mist system 13-1 is connected to the oil inlet of the oil cooling channel through a pipeline, and the oil mist flow control valve 13-3 and the oil mist device 13-2 are arranged on the pipeline. The oil outlet of the oil cooling channel is connected to the oil mist system 13-1;

[0057] The temperature proportional controller is connected to the oil mist flow control valve 13-3. When the water cooling component is working, the temperature proportional controller determines that the temperature information collected by the temperature sensor still exceeds the set temperature threshold, and the temperature proportional controller controls the switch and flow size of the oil mist flow control valve 13-3 to cool down the electric spindle rotor component 1 and the electric spindle stator component 2;

[0058] When the temperature is higher than the set temperature, the cooling fan 12-4 will adjust the fan speed to increase the cooling rate. After the cooling fan 12-4 is adjusted to the maximum limit, if the temperature value detected by the temperature sensor 11 is still higher than the set temperature and continues for a preset time period, which is adjustable, the oil mist flow control valve 13-3 begins to increase the pressure and increase the oil supply to achieve the reduction of the spindle temperature by the oil mist device 13-2, thereby realizing intelligent control of the electric spindle bearing temperature.

[0059] An intelligent monitoring and control system for an electric spindle also includes a signal acquisition control system 15. Vibration sensors 16 are respectively provided on the outer sides of the front end bearing 1-5 and the rear end bearing 1-6 of the electric spindle rotor assembly 1. The vibration sensors collect vibration information of the front end bearing 1-5 and the rear end bearing 1-6, and transmit the vibration information to the signal acquisition control system 15. The signal acquisition control system 15 determines the use performance of the front end bearing 1-5 and the rear end bearing 1-6 according to the vibration information.

[0060] The front-end vibration sensor is connected to the signal acquisition control system 15 through a transmission line passing through the first sensor hole on the front-end bearing seat 4. The front-end vibration sensor is in contact with the front-end bearing 1-5, and collects the vibration signal of the front-end bearing 1-5 in real time, transmits the front-end bearing vibration information to the signal acquisition control system 15 and displays it on the interface of the signal acquisition control system 15; the rear-end vibration sensor is connected to the signal acquisition control system 15 through a transmission line passing through the second sensor hole on the rear bearing seat 8. The rear-end bearing vibration sensor is in contact with the rear-end bearing 1-6, and collects the vibration signal of the rear-end bearing 1-6 in real time, transmits the rear-end bearing vibration information to the signal acquisition control system 15 and displays it on the interface of the signal acquisition control system 15. By analyzing the bearing vibration signal, the bearing performance during the operation of the electric spindle can be clarified, and timely and effective maintenance can be achieved to avoid affecting the operation accuracy of the electric spindle.

[0061] The front end of the electric spindle rotor assembly 1 is connected to a first front end displacement sensor 17 and a second front end displacement sensor 18 through a displacement sensor fixing frame 10. The first front end displacement sensor 17 is used to detect the displacement of the front end bearing 1-5 of the electric spindle rotor assembly 1 in the Y direction, and the second front end displacement sensor 18 is used to detect the displacement of the front end bearing 1-5 in the X direction of the electric spindle rotor assembly 1.

[0062] The rear end of the electric spindle rotor assembly 1 is connected to a first rear end displacement sensor 19 through a rear end cover 9, and the first rear end displacement sensor 19 is used to detect the displacement of the rear end bearing 1-6 of the electric spindle rotor assembly 1 in the Z direction; specifically: the displacement sensor fixing frame 10 is connected to the front bearing seat sealing end cover 5 through bolts, and conical bolts are installed on the displacement sensor fixing frame 10 to fix the first front end displacement sensor 17 and the second front end displacement sensor 18, which are used to detect the output accuracy of the front end shaft of the electric spindle. The first rear end displacement sensor 19 is placed through the center hole position of the rear end cover 9 of the electric spindle, and is used to detect the change of the axial displacement of the electric spindle during operation, and the real-time displacement of the electric spindle shaft collected by the displacement sensor is transmitted to the signal acquisition control system 15 and displayed in the interface of the signal acquisition control system 15;

[0063] The rear end of the electric spindle rotor assembly 1 is provided with an adjustable preload assembly 7, and the adjustable preload assembly 7 is fixed on the electric spindle rotor assembly 1 through a rear bearing seat 8. The adjustable preload assembly 7 includes a piezoelectric ceramic front retaining structure 7-1, a piezoelectric ceramic rear support structure 7-2, and a piezoelectric ceramic sensor 7-3. The piezoelectric ceramic front retaining structure 7-1 and the piezoelectric ceramic rear support structure 7-2 are respectively fixed on the rear bearing seat 8, and the piezoelectric ceramic sensor 7-3 is placed in the middle of the piezoelectric ceramic front retaining structure 7-1 and the piezoelectric ceramic rear support structure 7-2. Specifically, the piezoelectric ceramic front retaining structure 7-1 is connected to the rear bearing seat 8, the piezoelectric ceramic sensor 7-3 is placed in the piezoelectric ceramic rear support structure 7-2, and the piezoelectric ceramic front retaining structure 7-1 is connected to the rear bearing seat 8. -2 is fixed to the rear bearing seat 8 by bolts, the piezoelectric ceramic front holding structure 7-1 is provided with three cylindrical blind holes, and a through hole is provided at the center of the blind hole to be flush with the center of the bearing outer ring, the piezoelectric ceramic rear support structure 7-2 is provided with three cylindrical blind holes at the same position as the piezoelectric ceramic front holding structure 7-1, and a through hole is provided at the side of the blind hole to connect the sensor line, and the sensor line is connected to the piezoelectric ceramic sensor 7-3. The position of the piezoelectric ceramic sensor 7-3 is adjusted by the adjustment bolt behind the piezoelectric ceramic rear support structure 7-2, thereby ensuring that the contact between the sensor and the bearing outer ring is at the same horizontal position, ensuring that the three piezoelectric ceramics can act on the bearing outer ring at the same time, and realizing the uniform adjustment of the preload force;

[0064] The displacement value information of the first front-end displacement sensor 17, the second front-end displacement sensor 18, and the first rear-end displacement sensor 19 is transmitted to the signal acquisition and control system 15, and the signal acquisition and control system 15 controls the piezoelectric ceramic sensor 7-3 to adjust the preload; this is to adjust the preload of the intelligent electric spindle by expanding and contracting the piezoelectric ceramic under different current and voltage conditions on the basis of the existing spring preload. When the electric spindle shaft produces axial displacement due to temperature changes during the operation of the electric spindle, resulting in a change in the preload of the electric spindle, in order to compensate for the preload, an analog electrical signal is given to the piezoelectric ceramic sensor 7-3 through the signal acquisition and control system 15, and the piezoelectric ceramic component changes the displacement, pushing the outer ring of the bearing to move, thereby realizing the control of the preload, that is, realizing the adjustment of the preload of the electric spindle during operation.

[0065] By detecting the change in displacement of the electric spindle to evaluate the running accuracy of the electric spindle, a control method for an intelligent monitoring and control system of the electric spindle includes the following steps:

[0066] Step 1: The electric spindle is running, the temperature sensor 11 detects the real-time temperature values ​​of the front end bearing 1-5 and the rear end bearing 1-6, the first front end displacement sensor 17 and the second front end displacement sensor 18 detect the displacement of the front end bearing 1-5 in the X and Y directions respectively, and the first rear end displacement sensor 19 detects the displacement of the rear end bearing 1-6 in the Z direction;

[0067] Step 2: When the displacement of the front end bearing 1-5 in the X and Y directions or the displacement of the rear end bearing 1-6 in the Z direction exceeds the set threshold, the signal acquisition control system 15 controls the piezoelectric ceramic sensor 7-3 to operate, thereby adjusting the preload force of the electric spindle;

[0068] Step 3: When the temperature detected by the temperature sensor 11 exceeds the set threshold, the temperature proportional controller 14 controls the cooling fan 12-4 to start. At the same time, according to the temperature of the front end bearing 1-5 or the rear end bearing 1-6 detected by the temperature sensor 11, the power of the cooling fan 12-4 is adjusted, and the cooling water circulates in the water cooling channel to cool down the electric spindle rotor assembly 1 and the electric spindle stator assembly 2. After a preset period of time, when the temperature detected by the temperature sensor 11 is lower than the set threshold, the cooling fan 12-4 stops working; when the cooling fan stops working, if the temperature detected by the temperature sensor 11 is still higher than the set threshold, the temperature proportional controller 14 controls the oil mist flow control valve 13-3 to work for a preset period of time, and the oil mist flow control valve 13-3 starts to increase the pressure and increase the oil supply, so as to realize the reduction of the spindle temperature by the oil mist device 13-2, thereby realizing the intelligent regulation of the electric spindle bearing temperature.

[0069] The present invention can realize constant temperature control of the temperature rise inside the electric spindle. When the spindle is subjected to load and the rotation speed increases, the temperature rise increases, which will affect the thermal deformation of the rotating shaft. The temperature rise of the three positions of the high and low positions of the bearing is collected by the temperature sensor and compared with the set temperature value. When the temperature rise is greater than the set value, the cooling fan in the cooling control component increases the cooling speed to reduce the temperature. When the temperature stabilizes to the set temperature, the cooling fan maintains a constant speed. When the cooling fan speed is not enough to reduce the temperature, the oil supply of the oil pump is increased to reduce the spindle temperature. When it is reduced to the set value, the oil pump maintains the oil inlet rate.

[0070] The temperature rise of the spindle will change after being loaded, and the temperature change affects the axial deformation of the shaft, that is, the change in preload. This in turn affects the vibration value of the spindle, and the change in vibration value will lead to a decrease in the spindle machining accuracy. How to effectively achieve high-precision operation of the spindle, that is, how to reduce the change in axial displacement caused by the temperature rise of the spindle, by detecting the displacement changes in the XYZ directions of the spindle, to achieve the budget of the change in the preload force of the spindle, and by controlling the current or voltage signal of the piezoelectric sensor to change the expansion and contraction of the piezoelectric ceramic, thereby achieving preload compensation.

[0071] Control program based on cooling system:

[0072] % Initialization parameters

[0073] cooling_active = true; % Cooling system initial state (always on)

[0074] lubrication_active = true; % Lubrication system initial state (always on)

[0075] lubrication_maxactive = false; % Lubrication system oil valve increase status (initial closed)

[0076] temperature = a; % initial temperature (unit: Celsius)

[0077] threshold=b; % temperature threshold (when the temperature exceeds this value, the lubrication system is turned on)

[0078] min_cooling_rate=-c; % cooling pump minimum cooling rate (corresponding to the minimum speed)

[0079] max_cooling_rate = -d; % Maximum cooling rate of cooling pump (corresponding to maximum speed)

[0080] max_speed = x; % Maximum speed of cooling pump (assumed)

[0081] speed_increase_rate = e; % Speed ​​increment for each temperature rise (assumption)

[0082] lubrication_rate = -f; % Normal cooling rate of lubrication system (0.1 degree per second)

[0083] lubrication_maxrate = -g; % Lubrication system oil valve increases the cooling rate (cooling 0.2 degrees per second)

[0084] sensor_update_time=h; % Update the sensor reading value once per second

[0085] current_speed=k;%Current cooling pump speed (unit: rpm)

[0086] cooling_rate=min_cooling_rate; % Cooling rate is initialized to the minimum rate

[0087] %Simulation run

[0088] for t=1:300% simulation for 300 seconds

[0089] %Simulate the sensor to read the spindle temperature in real time (assuming that the sensor reading value is equal to the current temperature each time)

[0090] % You can adjust the temperature reading method according to the actual situation. Here we directly use the variable temperature

[0091] sensor_temperature=temperature;

[0092] % Update spindle temperature

[0093] if cooling_active

[0094] if lubrication_active

[0095] temperature=sensor_temperature+cooling_rate+lubrication_rate;%Cooling system cooling+normal lubrication system cooling

[0096] end

[0097] end

[0098] % Adjust the cooling pump speed when the spindle temperature rises

[0099] If temperature <threshold&¤t_speed<max_speed

[0100] %When the temperature rises to a certain degree, increase the cooling pump speed

[0101] speed_increase=speed_increase_rate*(temperature-25) / 5; % Assume that the speed increases every 5 degrees

[0102] current_speed=min(current_speed+speed_increase,max_speed);

[0103] % Adjust the cooling rate according to the current speed

[0104] if current_speed<=x / 3

[0105] cooling_rate=-c;% low speed range

[0106] elseif current_speed<=2x / 3

[0107] cooling_rate=-2c; % medium speed range

[0108] elseif current_speed<=x

[0109] cooling_rate=-3c;% high speed range

[0110] else

[0111] cooling_rate=-4c;% Maximum speed range

[0112] end

[0113] end

[0114] % If the spindle temperature exceeds the threshold, open the lubrication system oil valve to increase

[0115] if temperature>threshold&&~lubrication_active

[0116] lubrication_maxactive=true;

[0117] disp('The temperature exceeds the threshold, turn on the lubrication device');

[0118] end

[0119] % After the oil valve of the lubrication system is opened, the temperature continues to drop

[0120] if lubrication_maxactive

[0121] temperature=temperature+lubrication_maxrate; % lubrication system cooling

[0122] end

[0123] % Output current status

[0124] fprintf('Time: %d seconds, current temperature: %.2f℃, current speed: %.2f RPM, cooling system: %s, lubrication system oil valve increase status: %s\n',...

[0125] t,temperature,current_speed,mat2str(cooling_active),mat2str(lubrication_maxactive));

[0126] % If the temperature is below the threshold, close the lubrication system oil valve to increase the state

[0127] If temperature <threshold&&lubrication_maxactive

[0128] lubrication_maxactive=false;

[0129] disp('The temperature returns to normal, close the lubricating oil valve enlargement device');

[0130] end

[0131] %Wait 1 second (simulation time interval)

[0132] pause(sensor_update_time);

[0133] end

[0134] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope defined by the claims of the present invention.

Claims

1. An intelligent monitoring and control system for an electric spindle, characterized in that: Including electric spindle rotor assembly, electric spindle stator assembly, temperature control assembly, temperature proportional controller, An electric spindle stator assembly and an electric spindle housing are sequentially arranged on the outer side of the electric spindle rotor assembly, and a plurality of temperature sensors are evenly distributed on the outer sides of the front end bearing and the rear end bearing of the electric spindle rotor assembly; The temperature control component includes a water cooling control component and an oil cooling control component. The water cooling control component is connected to the cold water channel on the electric spindle housing through a pipeline, and the water cooling control component is used to cool the electric spindle rotor component and the electric spindle stator component. The oil cooling control component is connected to the oil cooling channel on the electric spindle housing through a pipeline, and the oil cooling control component is used to cool the electric spindle rotor component and the electric spindle stator component. The temperature sensor, water cooling control component, and oil cooling control component are connected to the temperature proportional controller. The temperature value collected by the temperature sensor is transmitted to the temperature proportional controller. The temperature proportional controller determines that the collected temperature information exceeds the set temperature threshold. The temperature proportional controller controls the water cooling control component to work and continues for a preset time period. If the temperature value collected by the temperature sensor is less than the set temperature threshold, the water cooling control component stops working; if the water cooling control component continues to work for a preset time period, the temperature value collected by the temperature sensor is still greater than the set temperature threshold, and the duration reaches the preset time period, the temperature proportional controller controls the oil cooling control component to work until the temperature value collected by the temperature sensor is less than the set temperature threshold.

2. The intelligent monitoring and control system of an electric spindle according to claim 1 is characterized in that: The water cooling control component includes a water pump, a cooling fan, and a water pipe. The water inlet of the water pump is connected to the water tank, and the water outlet of the water pump is connected to the water storage tank. A cooling fan is provided on one side of the water storage tank. The cooling fan is driven by a fan motor. The cooling fan cools the water in the water storage tank. The water outlet of the water storage tank is connected to the water inlet of the cold water channel through a pipe joint, and the water outlet of the cold water channel is connected to the water tank; The temperature proportional controller is connected to the fan motor. The temperature proportional controller determines that the temperature information collected by the temperature sensor exceeds the set temperature threshold. The temperature proportional controller controls the fan motor to start and adjusts the fan motor power to adjust the cooling fan speed. If the cooling fan speed is modulated to the maximum limit and continues for a preset time period, the temperature value collected by the temperature sensor is less than the set temperature threshold, the oil cooling control component is started.

3. The intelligent monitoring and control system of an electric spindle according to claim 1 is characterized in that: The oil cooling control assembly includes an oil mist system, an oil mist device, an oil mist flow control valve, and an oil pipe. The oil mist system is connected to the oil inlet of the oil cooling channel through a pipeline. The oil mist flow control valve and the oil mist device are arranged on the pipeline. The oil outlet of the oil cooling channel is connected to the oil mist system. The temperature proportional controller is connected to the oil mist flow control valve. When the water cooling component is working, the temperature proportional controller determines that the temperature information collected by the temperature sensor still exceeds the set temperature threshold. The temperature proportional controller controls the oil mist flow control valve switch and flow rate to cool down the electric spindle rotor assembly and the electric spindle stator assembly.

4. The intelligent monitoring and control system of an electric spindle according to claim 1, characterized in that: It also includes a signal acquisition control system. Vibration sensors are respectively provided on the outside of the front end bearing and the rear end bearing of the electric spindle rotor assembly. The vibration sensors collect vibration information of the front end bearing and the rear end bearing, and transmit the vibration information to the signal acquisition control system. The signal acquisition control system determines the performance of the front end bearing and the rear end bearing based on the vibration information.

5. The intelligent monitoring and control system of an electric spindle according to claim 1, characterized in that: The front end of the electric spindle rotor assembly is connected to a first front end displacement sensor and a second front end displacement sensor through a displacement sensor fixing frame, wherein the first front end displacement sensor is used to detect the displacement of the front end bearing of the electric spindle rotor assembly in the Y direction, and the second front end displacement sensor is used to detect the displacement of the front end bearing of the electric spindle rotor assembly in the X direction; The rear end of the electric spindle rotor assembly is connected to a first rear end displacement sensor through a rear end cover, and the first rear end displacement sensor is used to detect the displacement of the rear end bearing of the electric spindle rotor assembly in the Z direction; An adjustable preload component is provided at the rear end of the electric spindle rotor assembly, and the adjustable preload component is fixed on the electric spindle rotor assembly through a rear bearing seat. The adjustable preload component includes a piezoelectric ceramic front holding structure, a piezoelectric ceramic rear supporting structure, and a piezoelectric ceramic sensor. The piezoelectric ceramic front holding structure and the piezoelectric ceramic rear supporting structure are respectively fixed on the rear bearing seat, and the piezoelectric ceramic sensor is placed between the piezoelectric ceramic front holding structure and the piezoelectric ceramic rear supporting structure. The displacement value information of the first front-end displacement sensor, the second front-end displacement sensor, and the first rear-end displacement sensor is transmitted to the signal acquisition control system, and the signal acquisition control system controls the piezoelectric ceramic sensor to adjust the preload force.

6. A control method for an intelligent monitoring and control system of an electric spindle, applicable to the intelligent monitoring and control system of an electric spindle according to claim 1, characterized in that: The following steps are involved: Step 1: The electric spindle is running, the temperature sensor detects the real-time temperature values ​​of the front-end bearing and the rear-end bearing, the first front-end displacement sensor and the second front-end displacement sensor detect the displacement of the front-end bearing in the X and Y directions respectively, and the first rear-end displacement sensor detects the displacement of the rear-end bearing in the Z direction; Step 2: When the displacement of the front end bearing in the X and Y directions or the displacement of the rear end bearing in the Z direction exceeds the set threshold, the signal acquisition control system controls the piezoelectric ceramic sensor to adjust the preload force of the electric spindle; Step 3: When the temperature detected by the temperature sensor exceeds the set threshold, the temperature proportional controller controls the cooling fan to start. At the same time, according to the temperature of the front end bearing or the rear end bearing detected by the temperature sensor, the power of the cooling fan is adjusted. The cooling water circulates in the water cooling channel to cool down the electric spindle rotor assembly and the electric spindle stator assembly. After a preset period of time, when the temperature detected by the temperature sensor is lower than the set threshold, the cooling fan stops working. When the cooling fan stops working, if the temperature detected by the temperature sensor is still higher than the set threshold, the temperature proportional controller controls the oil mist flow control valve to work, thereby reducing the temperature of the electric spindle rotor assembly and the electric spindle stator assembly.

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