Turning, milling and grinding monitoring composite numerical control machine tool

Abstract

The invention discloses a turning, milling and grinding monitoring composite numerical control machine tool, belongs to the technical field of numerical control machine tools, and solves the problem that on the basis of changes of thermal expansion and thermal deformation of a main shaft, the situation that the main shaft vibrates is not simply solved by adding a vibration compensation algorithm and a main shaft thermal error compensation algorithm. Comprising a lathe bed, a bearing seat arranged on the lathe bed, a main shaft rotationally arranged in the bearing seat, an outer ring temperature acquisition module arranged in the bearing seat, an inner ring temperature acquisition module arranged at one end of the main shaft, a data processing module and a control module, wherein the two ends of the main shaft penetrate to the outside. The temperature of the inner ring and the outer ring of the main shaft is obtained through a temperature sensor and thermal imaging, the temperature in the wall thickness direction is judged by combining data, vibration data in a database are matched and stored in a picture form, the result is accurate, the data processing burden is relieved, and time is shortened; otherwise, the electromagnetic valve is opened, vortex heat dissipation is formed through the inner blades, and temperature rise of the spindle is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of numerical control machine tools, and particularly relates to a turning, milling and grinding monitoring composite numerical control machine tool. Background Art

[0002] A numerical control machine tool is a highly automated and precise machining device, which is widely used in many fields such as mechanical manufacturing, aerospace, automobile manufacturing, electronic equipment, etc. It controls the movement and machining process of the machine tool through a computer numerical control system (CNC), and can achieve high-precision and high-efficiency machining. The main components of a numerical control machine tool include a bed, a spindle, a feed system, a tool system and a control system. The bed is the basic structure of the machine tool, supporting and fixing other components. The spindle is the core component of the machine tool, responsible for driving the workpiece or tool to rotate. The feed system controls the feed movement of the tool or workpiece to ensure machining accuracy. The tool system includes tools and tool clamping devices for cutting workpieces. The control system is the brain of the numerical control machine tool, controlling the movement and machining process of the machine tool through the input machining program. Numerical control machine tools have the advantages of high precision, high efficiency, high automation, stable machining quality, etc., can machine parts with complex shapes, and improve production efficiency and product quality. With the continuous development of technology, numerical control machine tools are developing towards the direction of intelligence, networking and high efficiency, providing strong technical support for modern manufacturing.

[0003] During the working process of the numerical control machine tool, the cutting piece held by the three-jaw chuck at one end of the spindle contacts the tool for turning and milling operations. During this process, a large amount of heat is generated when the tool turns and mills the cutting piece, and this heat will be transferred to the three-jaw chuck through the cutting piece. Since the three-jaw chuck is fixedly connected to the spindle, the heat on the three-jaw chuck will then be transferred to the spindle, from one end of the spindle to the other end;

[0004] During this process, the driving motor that drives the spindle to rotate will also generate corresponding heat due to the load, and the heat on the driving motor will be directly transferred to the end that is in transmission connection with the spindle;

[0005] In the combination of the above two situations, the spindle will be thermally conducted by the heat sources at both ends, and then the spindle will gradually heat up from both ends during the machining of the cutting piece. During this process, the thermal expansion and thermal deformation of the spindle will become more obvious, and finally the spindle will show axial deformation and radial deformation, ultimately resulting in a change in the position of the three-jaw chuck and the cutting piece thereon, while the position of the tool has not been adjusted, which also leads to poor accuracy of the parts machined by the numerical control machine tool.

[0006] To solve this problem, current CNC machine tools adopt a combination of two means for effective improvement. One is to achieve the transmission connection between the driving motor and the spindle through a transmission pulley set. In this way, the driving motor and the spindle do not come into direct contact, which prevents the heat on the driving motor from being transferred to the spindle, reducing the spindle's temperature rise rate and also alleviating its thermal expansion and thermal deformation. The other is to calculate the displacement of the cutting part through the spindle thermal error compensation algorithm, and then adjust the orientation of the tool, so that the final obtained parts can still maintain good precision.

[0007] However, even with the support of these two current methods, the upper temperature limit of the spindle will not be reduced thereby. One method can only delay the spindle's temperature rise rate, and the other method does not help improve the spindle's temperature at all. As a result, the spindle not only vibrates slightly due to its own thermal expansion and thermal deformation, but also, when the spindle's temperature rise spreads to the positions of structures such as the bearing housing, angular contact bearing set, and rear bearing outside the spindle, the rotation of the bearing housing, angular contact bearing set, rear bearing, etc. outside the spindle becomes less smooth due to the spindle's thermal expansion and thermal deformation, that is, the rotation of the spindle becomes somewhat sluggish. Under the influence of the speed differential between the driving motor and the transmission pulley set, the vibration of the spindle is aggravated. Normally, only by using the vibration compensation algorithm to estimate the displacement of the spindle's vibration situation and then adjusting the orientation of the tool can solve the problem. However, based on the changes in the spindle's thermal expansion and thermal deformation, when the spindle vibration occurs again, it cannot be simply solved by adding the vibration compensation algorithm and the spindle thermal error compensation algorithm. Therefore, the occurrence of such a problem will cause irreversible damage to the structure of the CNC machine tool and affect the working precision of the CNC machine tool during subsequent machining.

[0008] Therefore, a turning-milling-grinding monitoring composite CNC machine tool is proposed to solve or alleviate the above problems. Summary of the Invention

[0009] The purpose of the present invention is to solve the deficiencies existing in the prior art and propose a turning-milling-grinding monitoring composite CNC machine tool.

[0010] To achieve the above purpose, the present invention adopts the following technical solutions:

[0011] A turning-milling-grinding monitoring compound numerical control machine tool includes a bed body, a bearing seat arranged on the bed body, a main shaft rotatably arranged in the bearing seat and penetrating through both ends to the outside, an outer ring temperature acquisition module arranged in the bearing seat, an inner ring temperature acquisition module arranged at one end of the main shaft, a data processing module, and a control module. One end of the main shaft is provided in an openable and closable manner. The outer ring temperature acquisition module is used to acquire the temperature condition of the outer ring of the main shaft and feedback it to the data processing module. The inner ring temperature acquisition module is used to acquire the temperature condition of the inner ring of the main shaft and feedback it to the data processing module. The data processing module is used to generate an axial temperature map of the main shaft according to the temperature conditions of the inner and outer rings of the main shaft, judge the vibration critical condition through a matching model, and output the result to the control module. The control module is used to control the opening and closing of the air passage at one end of the main shaft according to the output result.

[0012] Preferably, the outer ring temperature acquisition module includes a plurality of temperature sensors. The plurality of temperature sensors are fixedly connected in the bearing seat. The plurality of temperature sensors are arranged at intervals in the length direction of the main shaft. The temperature sensors acquire the temperature of the outer ring of the main shaft and feedback the temperature signal to the data processing module.

[0013] Preferably, a three-jaw chuck fixedly connected to the inside thereof is arranged at one end of the main shaft. A driven wheel is coaxially and fixedly connected to the outer ring at the other end of the main shaft. A solenoid valve fixedly connected to the main shaft and communicating with it is arranged at one end of the main shaft passing through the driven wheel. The solenoid valve realizes the opening and closing of the air passage of the main shaft. The solenoid valve is coupled to the control module. The solenoid valve includes a valve body, a traction electromagnet fixedly connected to the valve body, and a valve core fixedly connected to the movable rod of the traction electromagnet and located inside the valve body. Both the valve body and the valve core are made of transparent materials.

[0014] Preferably, the inner ring temperature acquisition module includes a thermal imager. The thermal imager is arranged on the bed body. The camera of the thermal imager is arranged facing the channel of the solenoid valve. The camera is coaxially arranged with the channel of the solenoid valve. The thermal imager is used to acquire the thermal map of the inner ring of the main shaft and transmit it to the data processing module.

[0015] Preferably, the data processing module includes a processor. The processor is used to generate an axial temperature map of the main shaft according to the temperature conditions of the inner and outer rings of the main shaft, judge the vibration critical condition through a matching model, and output the result to the control module.

[0016] Preferably, the data processing module is used to generate an axial temperature map of the main shaft according to the temperature conditions of the inner and outer rings of the main shaft, judge the vibration critical condition through a matching model, and output the result to the control module, including the following steps.

[0017] Receive a plurality of temperature signals and estimate the temperature at any position in the axial direction of the outer ring of the main shaft. Convert the temperature at any position in the axial direction of the outer ring of the main shaft into a line expressing temperature change with color to obtain an outer ring temperature line.

[0018] Receive several inner ring heat maps of the main shaft, combine them, and then convert them into lines expressing temperature changes in color to obtain the inner ring temperature lines;

[0019] Fill the temperature change area between the outer ring temperature line and the inner ring temperature line through the outer ring temperature line and the inner ring temperature line, as well as the wall thickness of the main shaft, to obtain the main shaft temperature profile;

[0020] Adjust the main shaft temperature profile to a unified scale and input it into the matching model. The matching model outputs whether the vibration critical situation is about to occur or will not occur as the output result.

[0021] Preferably, receiving several temperature signals and estimating the temperature at any position in the axial direction of the outer ring of the main shaft, converting the temperature at any position in the axial direction of the outer ring of the main shaft into a line expressing temperature changes in color to obtain the outer ring temperature line, includes the following steps:

[0022] Use the one-dimensional steady-state heat conduction equation to describe the temperature distribution of the outer ring of the main shaft in the axial direction and set the boundary conditions;

[0023] According to the heat conduction equation and the boundary conditions, the finite difference method can be used to discretize the temperature distribution;

[0024] Use polynomial interpolation to calculate the temperature at any axial position;

[0025] Obtain the temperature data at each position in the axial direction of the outer ring of the main shaft and determine the coordinates of each position;

[0026] Normalize the temperature data at each position in the axial direction of the outer ring of the main shaft to obtain the normalized temperature;

[0027] Use the normalized temperature to map it to a color space to obtain the color value corresponding to each temperature;

[0028] For two adjacent positions and the corresponding color values, calculate the color at any position through linear interpolation to obtain the outer ring temperature line.

[0029] Preferably, receiving several inner ring heat maps of the main shaft, combining them, and then converting them into lines expressing temperature changes in color to obtain the inner ring temperature line, includes the following steps:

[0030] Extract the temperature data of the inner ring of the main shaft from each inner ring heat map of the main shaft, set the width of the inner ring heat map of the main shaft, the height of the inner ring heat map of the main shaft, and each pixel in the inner ring heat map of the main shaft represents the temperature of the inner ring of the main shaft at the corresponding position;

[0031] Set the number of thermal images of the inner ring of the main shaft, the range of axial positions, and each thermal image of the inner ring of the main shaft provides the temperature distribution at a corresponding position.

[0032] Extract the temperature information at the corresponding positions from each thermal image of the inner ring of the main shaft. The temperature data on each thermal image of the inner ring of the main shaft is a two-dimensional matrix.

[0033] Given the axial positions corresponding to each image and the temperature data at these positions, for the temperature data in different images, perform axial interpolation through spline interpolation to obtain the temperature distribution along the axis.

[0034] For each axial position, use the interpolation method to calculate the temperature value at this position, and the obtained temperature data is a one-dimensional temperature distribution sequence.

[0035] According to the calculated temperature distribution, use color mapping technology to convert the temperature value into a color, correspond the temperature value with the color, and generate the inner ring temperature line.

[0036] Preferably, fill the temperature change area between the outer ring temperature line and the inner ring temperature line, as well as the wall thickness of the main shaft, through the outer ring temperature line and the inner ring temperature line to obtain the main shaft temperature profile, including the following steps.

[0037] For any point between the outer ring temperature line and the inner ring temperature line, its corresponding temperature is obtained through linear interpolation.

[0038] Convert the temperature to color and calculate the color according to each position to form the main shaft temperature profile.

[0039] Preferably, the main shaft is tubular, and a first inner blade and a second inner blade are fixedly connected to the inner ring of the main shaft. The pitches of the first inner blade and the second inner blade are set to be the same, and there are distances from the first inner blade and the second inner blade to the end of the main shaft. The widths of the first inner blade and the second inner blade are both equal to the inner radius of the main shaft, and the first inner blade and the second inner blade are arranged in a staggered and overlapping manner.

[0040] The present invention has the following beneficial effects:

[0041] On the one hand, the present invention uses traditional temperature sensors to monitor the temperature of the outer ring of the main shaft, and on the other hand, obtains the temperature of the inner ring of the main shaft through thermal imaging technology. By integrating these data, the temperature distribution in the wall thickness direction of the main shaft is judged. Furthermore, based on the temperature data of the inner and outer rings of the main shaft and in the wall thickness direction, it is matched with a pre-stored vibration database, which stores data in the form of pictures. Through similarity comparison, accurate results are quickly output, effectively reducing the data processing burden, shortening the processing time, and improving work efficiency.

[0042] When the prediction result shows that the main shaft will not vibrate, the control module does not need to activate the solenoid valve. On the contrary, if the main shaft has a further tendency to heat up, it may cause the thermal compensation algorithm to fail and trigger vibration problems. At this time, the system will automatically open the solenoid valve to allow air to circulate at both ends of the main shaft. When the main shaft rotates at high speed, the first inner blade and the second inner blade inside will fan the air to form a vortex, accelerating the air flow, thereby quickly taking away the heat from the main shaft, the three-jaw chuck, and the cutting piece, preventing subsequent problems caused by overheating of the main shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0044] Figure 1 is a schematic structural diagram of the present invention;

[0045] Figure 2 is a schematic structural diagram of the main shaft, the bearing seat, and the solenoid valve in the present invention;

[0046] Figure 3 is a partial cross-sectional view of the main shaft in the present invention;

[0047] Figure 4 is a block diagram of the inner ring temperature acquisition module, the outer ring temperature acquisition module, the data processing module, the control module, and the wireless communication module in the present invention.

[0048] 1. Bed; 2. Main shaft; 3. Bearing seat; 4. Driven wheel; 5. Solenoid valve; 6. First inner blade; 7. Second inner blade; 8. Outer ring temperature acquisition module; 9. Inner ring temperature acquisition module; 10. Data processing module; 11. Control module; 12. Wireless communication module; 13. Relay. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0049] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and illustrated in the drawings here can be arranged and designed in various different configurations.

[0050] Accordingly, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0051] It should be noted that like reference numerals and letters denote like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

[0052] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use, or the orientation or positional relationship commonly understood by those skilled in the art. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0053] In addition, the terms "first", "second", "third", etc. are only used for descriptive distinction and should not be construed as indicating or implying relative importance.

[0054] In the description of the present invention, it should also be noted that unless otherwise clearly specified and limited, the terms "set", "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0055] A turning, milling and grinding monitoring compound CNC machine tool, such as Figure 1 、 Figure 2 and Figure 4As shown in the figure, it includes a bed body 1, a bearing block 3 arranged on the bed body 1, a main shaft 2 rotatably arranged in the bearing block 3 and penetrating through to the outside at both ends, an outer ring temperature acquisition module 8 arranged in the bearing block 3, an inner ring temperature acquisition module 9 arranged at one end of the main shaft 2, a data processing module 10, and a control module 11. One end of the main shaft 2 is provided in an openable and closable manner. The outer ring temperature acquisition module 8 is used to acquire the temperature condition of the outer ring of the main shaft 2 and feedback it to the data processing module 10. The inner ring temperature acquisition module 9 is used to acquire the temperature condition of the inner ring of the main shaft 2 and feedback it to the data processing module 10. The data processing module 10 is used to generate an axial temperature map of the main shaft 2 according to the temperature conditions of the inner and outer rings of the main shaft 2, judge the vibration critical condition through a matching model, and output the result to the control module 11. The control module 11 is used to control the opening and closing of the air passage at one end of the main shaft 2 according to the output result.

[0056] The outer ring temperature acquisition module 8 includes a number of temperature sensors. The number of temperature sensors are fixedly connected in the bearing block 3. The number of temperature sensors are arranged at intervals in the length direction of the main shaft 2. The temperature sensors acquire the temperature of the outer ring of the main shaft 2 and feedback the temperature signal to the data processing module 10. The inner ring temperature acquisition module 9 includes an infrared thermal imager. The infrared thermal imager is arranged on the bed body 1, and the camera of the infrared thermal imager is arranged facing the channel of the solenoid valve 5. The camera is coaxially arranged with the channel of the solenoid valve 5. The infrared thermal imager is used to acquire the thermal image of the inner ring of the main shaft 2 and transmit it to the data processing module 10. The data processing module 10 includes a processor. The processor is used to generate an axial temperature map of the main shaft 2 according to the temperature conditions of the inner and outer rings of the main shaft 2, judge the vibration critical condition through a matching model, and output the result to the control module 11. The control module 11 includes a controller. A power supply is fixedly connected to the solenoid valve 5. The solenoid valve 5 is connected to the power supply through a relay 13. The controller is coupled to the relay 13 through a wireless communication module 12. The wireless communication module 12 includes a Bluetooth module.

[0057] As Figure 3 shown, the main shaft 2 is tubular, and a first inner blade 6 and a second inner blade 7 are fixedly connected to the inner ring of the main shaft 2. The pitches of the first inner blade 6 and the second inner blade 7 are set to be the same, and there are distances from the first inner blade 6 and the second inner blade 7 to the end of the main shaft 2. The widths of the first inner blade 6 and the second inner blade 7 are both equal to the inner radius of the main shaft 2. The first inner blade 6 and the second inner blade 7 are arranged in a staggered and overlapping manner.

[0058] As Figure 2As shown, one end of the main shaft 2 is fixedly connected with a three-jaw chuck that is internally connected to it. The outer ring of the other end of the main shaft 2 is coaxially and fixedly connected with a driven wheel 4. One end of the main shaft 2 passes through the driven wheel 4 and is fixedly connected with a solenoid valve 5 that is connected to it. The solenoid valve 5 realizes the opening, closing, and air on-off of the main shaft 2. The solenoid valve 5 is coupled to the control module 11. The solenoid valve 5 includes a valve body, a traction electromagnet fixedly connected to the valve body, and a valve core fixedly connected to the movable rod of the traction electromagnet and located inside the valve body. Both the valve body and the valve core are made of transparent materials.

[0059] The present invention can not only collect the temperature of the outer ring of the main shaft 2 through the temperature collection means of a conventional temperature sensor, but also obtain the temperature condition of the inner ring of the main shaft 2 through thermal imaging. Combining the two situations, it judges the temperature condition of the main shaft 2 in the wall thickness direction at this time, and directly matches and correlates the data in the database where vibration will occur or will not occur based on the temperature conditions of the inner and outer rings of the main shaft 2 and in the wall thickness direction at this time. At the same time, these data will be stored in the form of pictures. During the association and comparison process, relatively accurate results can be output through similarity comparison, reducing the workload of the data processing module 10, shortening the time for outputting results, accelerating its working process. When the output result is that vibration will not occur, then the control module 11 does not need to open the solenoid valve 5. On the contrary, it means that if the main shaft 2 is further heated up, it will cause the problem that the thermal compensation algorithm cannot correct the orientation and the main shaft 2 will vibrate further. Then at this time, it is necessary to open the solenoid valve 5 so that air can flow through both ends of the main shaft 2. And under the rapid rotation of the main shaft 2, the first inner blade 6 and the second inner blade 7 in the main shaft 2 can fan the air to form a vortex, enabling the air to flow in the main shaft 2 at a relatively fast flow rate, taking away the heat on the main shaft 2, the three-jaw chuck, and even the cutting piece, thus avoiding subsequent problems caused by the further heating of the main shaft 2.

[0060] Preferably, the data processing module 10 is used to generate an axial temperature map of the main shaft 2 according to the temperature conditions of the inner and outer rings of the main shaft 2, judge the vibration critical situation through a matching model, and output the result to the control module 11, including the following steps:

[0061] Receive a number of temperature signals and estimate the temperature at any position in the axial direction of the outer ring of the main shaft 2, and convert the temperature at any position in the axial direction of the outer ring of the main shaft 2 into a line expressing temperature change with color to obtain an outer ring temperature line;

[0062] Receive a number of thermal maps of the inner ring of the main shaft 2 and combine them to convert them into a line expressing temperature change with color to obtain an inner ring temperature line;

[0063] The temperature change region between the outer ring temperature line and the inner ring temperature line, as well as the wall thickness of the main shaft 2, is filled to obtain the main shaft temperature profile diagram;

[0064] The main shaft temperature profile diagram is adjusted to a unified scale and input into the matching model, and the matching model outputs the vibration critical situation as about to vibrate or not vibrate as the output result.

[0065] According to the above method steps, the main shaft temperature profile diagram is generated, and the vibration critical situation of the main shaft 2 is judged through the matching model. This method can provide a simpler and more intuitive temperature distribution and vibration prediction. Compared with the simple temperature monitoring method, this multi-step processing method can more comprehensively understand the thermal state of the main shaft 2, so as to more accurately predict the vibration situation of the main shaft 2 and improve the operation efficiency and processing accuracy of the equipment.

[0066] Preferably, several temperature signals are received and the temperature at any position in the axial direction of the outer ring of the main shaft 2 is estimated. The temperature at any position in the axial direction of the outer ring of the main shaft 2 is converted into a line expressing the temperature change with color to obtain the outer ring temperature line, including the following steps,

[0067] The one-dimensional steady-state heat conduction equation is used to describe the temperature distribution in the axial direction of the outer ring of the main shaft 2. The heat conduction equation includes where T(x) represents the temperature at the axial position x of the outer ring of the main shaft 2, x represents the axial position of the main shaft 2, and x ∈ [x 1 , x N , that is, from one end to the other end of the main shaft 2, boundary conditions are set. Through the temperature acquisition points on the outer ring of the main shaft 2 at different positions x i of the outer ring of the main shaft 2, the known temperature T i is obtained. These temperature points will be used as data sources. Assuming that the temperature T 1 at one end of the main shaft 2 is known, and the temperature T N at the other end is also known;

[0068] According to the heat conduction equation and the boundary conditions, the finite difference method can be used to discretize the temperature distribution to obtain the temperature at each axial position. The discretization equation includes T i+1 - 2T i + T i-1 = 0;

[0069] Polynomial interpolation is used to calculate the temperature at any axial position where L i (x) is the Lagrange basis function;

[0070] Through T(x), the temperature data at each position in the axial direction of the outer ring of the main shaft 2 is obtained, and the coordinates X of each position are determined i, where i represents the i-th position;

[0071] Normalize the temperature data at each position of the outer ring of the main shaft 2 in the axial direction to obtain the normalized temperature where, T min and T max are the maximum temperature data and the minimum temperature data respectively;

[0072] Use the normalized temperature T′ i to map it to a color space to obtain the color value C i corresponding to each temperature T′ i ;

[0073] For two adjacent positions of X i and X i+1 , and the corresponding color values C i and C i+1 , calculate the color at any position through linear interpolation. The linear interpolation includes where, C(x) is the color value at any axial position x;

[0074] Connect each X i and the corresponding color value C i to obtain the outer ring temperature line.

[0075] Through the above method steps, using the one-dimensional steady-state heat conduction equation and the finite difference method, the temperature at any position of the outer ring of the main shaft 2 in the axial direction can be calculated. This method can provide high-precision temperature distribution data, which helps to generate more accurate temperature lines. Compared with simple temperature measurement methods, this physical model-based calculation method can more comprehensively understand the thermal state of the main shaft 2 and improve the accuracy and reliability of monitoring.

[0076] Preferably, receive several inner ring heat maps of the main shaft 2 and combine them to convert them into a line expressing temperature change in color to obtain the inner ring temperature line, including the following steps,

[0077] Extract the temperature data of the inner ring of the main shaft 2 from each inner ring heat map of the main shaft 2. Set the width of the inner ring heat map of the main shaft 2 as M, the height as N, and each pixel (i, j) in the inner ring heat map of the main shaft 2 represents the temperature T i , y j ) at the corresponding position (x ij ;

[0078] Set the number of inner ring heat maps of the main shaft 2 as x, and the range of the axial position as x x , and each inner ring heat map of the main shaft 2 provides a temperature distribution at a corresponding position;

[0079] Extract the temperature information at the corresponding positions from the thermal maps of the inner rings of each main shaft 2. For each extraction of the temperature information at the corresponding positions, the temperature data T on each thermal map i of the inner ring of the main shaft 2 i is a two-dimensional matrix T i ={T ij | i = 1, 2, ..., M; j = 1, 2, ..., N}. For each thermal map i of the inner ring of the main shaft 2, select a fixed axial position x i , and extract the average temperature value or the temperature value at a specific position of the temperature data T i at this position;

[0080] Given the axial position x i corresponding to each image and the temperature data T i at this position, for the temperature data in different images, perform axial interpolation through spline interpolation to obtain the temperature distribution along the axis;

[0081] For each axial position x, use the interpolation method to calculate the temperature value T(x) at this position. The obtained temperature data is a one-dimensional temperature distribution sequence T(x 1 ), T(x 2 ), …, T(x X );

[0082] According to the calculated temperature distribution, use the color mapping technology to convert the temperature values into colors, correspond the temperature values with the colors, and generate the inner ring temperature lines.

[0083] Through the above method steps, by extracting the temperature data from the thermal maps and performing axial interpolation using spline interpolation, high-precision inner ring temperature lines can be generated. This method can provide detailed inner ring temperature distribution information, which helps to more accurately predict the thermal expansion and thermal deformation of the main shaft 2. Compared with simple temperature measurement methods, this interpolation method based on thermal maps can provide more comprehensive and accurate temperature information, improving the accuracy and reliability of monitoring.

[0084] Preferably, fill the temperature change region between the outer ring temperature lines and the inner ring temperature lines, as well as the wall thickness of the main shaft 2, to obtain the main shaft temperature profile, including the following steps,

[0085] Determine that the temperature on the outer ring temperature line is T a (x) and the temperature on the inner ring temperature line is T b (x), where x represents the position. The temperature change region between the outer ring temperature line and the inner ring temperature line is divided into N equally long points by the wall thickness of the main shaft 2, and the color is represented as a function C(T), where T is the temperature and C(T) is the corresponding color;

[0086] For any point x between the outer ring temperature line and the inner ring temperature line i (i = 1, 2,..., N - 1), the corresponding temperature T(x i ) is obtained by linear interpolation: Where, T a (x i ) and T b (x i ) are the temperatures of the outer ring temperature line and the inner ring temperature line at position x i respectively, and x a and x b are the starting positions corresponding to the outer ring temperature line and the inner ring temperature line respectively;

[0087] The temperature T(x i ) is converted into color C(x i ) = C(T(x i )) through the function C(T), where C(T(x i )) is the color corresponding to the temperature T(x i ), and the color C(x i ) is calculated according to each position x i to form the main axis temperature profile.

[0088] Through linear interpolation and color mapping techniques, a detailed main axis temperature profile can be generated. This method can visually display the temperature changes of the inner and outer rings of the main axis 2, which helps to more accurately predict the thermal expansion and thermal deformation of the main axis 2. Compared with simple temperature measurement methods, this interpolation and color mapping-based method can provide more comprehensive and intuitive temperature information, improve the accuracy and reliability of monitoring, and by comparing with the main axis temperature profile, the results can be output faster. At the same time, the data is saved in the form of the main axis temperature profile in the database, making the data more integral.

[0089] Preferably, the main axis temperature profile is adjusted to a unified scale and input into the matching model. The matching model outputs the vibration critical situation as about to vibrate or not vibrate as the output result, including the following steps,

[0090] Adjust the main axis temperature profile to a unified scale;

[0091] Compare the matching model, which is the Euclidean distance formula, with the main axis temperature profile in the database, and output the main axis temperature profile with the highest similarity. Obtain the vibration critical situation marked by this main axis temperature profile as the output result.

[0092] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A composite CNC machine tool for turning, milling and grinding monitoring, characterized in that: The invention comprises a bed (1), a bearing seat (3) arranged on the bed (1), a main shaft (2) rotatably arranged in the bearing seat (3) and having both ends extending to the outside, an outer ring temperature acquisition module (8) arranged in the bearing seat (3), an inner ring temperature acquisition module (9) arranged at one end of the main shaft (2), a data processing module (10), and a control module (11), wherein one end of the main shaft (2) can be opened and closed, the outer ring temperature acquisition module (8) is used to acquire the outer ring temperature of the main shaft (2) and feed it back to the data processing module (10), the inner ring temperature acquisition module (9) is used to acquire the inner ring temperature of the main shaft (2) and feed it back to the data processing module (10), the data processing module (10) is used to generate an axial temperature map of the main shaft (2) according to the inner and outer ring temperatures of the main shaft (2), judge the critical vibration situation through a matching model, and output the result to the control module (11), and the control module (11) is used to control the opening and closing of one end of the main shaft (2) according to the output result.

2. A turning, milling and grinding monitoring composite CNC machine tool according to claim 1, characterized in that: The outer ring temperature acquisition module (8) comprises a plurality of temperature sensors, wherein the plurality of temperature sensors are fixedly connected in the bearing seat (3), and the plurality of temperature sensors are arranged at intervals in the length direction of the main shaft (2). The temperature sensors acquire the outer ring temperature of the main shaft (2) and feed back the temperature signal to the data processing module (10).

3. The turning, milling and grinding monitoring composite CNC machine tool according to claim 1, characterized in that: One end of the main shaft (2) is fixedly connected to a three-jaw chuck connected to the inside thereof, and the other end of the main shaft (2) is coaxially fixedly connected to a driven wheel (4) on its outer ring. One end of the main shaft (2) that passes through the driven wheel (4) is fixedly connected to a solenoid valve (5) connected to the driven wheel. The solenoid valve (5) realizes the opening and closing of the main shaft (2) and the air supply. The solenoid valve (5) is coupled to a control module (11), and the solenoid valve (5) includes a valve body, a traction electromagnet fixedly connected to the valve body, and a valve core fixedly connected to a movable rod of the traction electromagnet and located in the valve body. The valve body and the valve core are both made of transparent material.

4. The turning, milling and grinding monitoring composite CNC machine tool according to claim 1, characterized in that: The inner ring temperature acquisition module (9) includes a thermal imager, which is arranged on the bed (1), and the camera of the thermal imager is arranged opposite to the channel of the solenoid valve (5), and the camera and the channel of the solenoid valve (5) are arranged coaxially. The thermal imager is used to collect the thermal map of the inner ring of the main shaft (2) and transmit it to the data processing module (10).

5. The turning, milling and grinding monitoring composite CNC machine tool according to claim 1, characterized in that: The data processing module (10) comprises a processor, which is used to generate an axial temperature diagram of the main shaft (2) according to the temperature conditions of the inner and outer rings of the main shaft (2), determine the critical vibration condition through a matching model, and output the result to the control module (11).

6. The turning, milling and grinding monitoring composite CNC machine tool according to claim 1, characterized in that: The data processing module (10) is used to generate an axial temperature map of the main shaft (2) according to the temperature conditions of the inner and outer rings of the main shaft (2), and to judge the critical vibration condition through a matching model and output the result to the control module (11), comprising the following steps: Receiving a plurality of temperature signals and estimating the temperature of the outer ring of the main shaft (2) at any position in the axial direction, converting the temperature of the outer ring of the main shaft (2) at any position in the axial direction into a line expressing the temperature change in color, thereby obtaining an outer ring temperature line; Receiving the inner circle thermal images of a plurality of main shafts (2) and combining them to convert them into lines expressing temperature changes in colors, thereby obtaining inner circle temperature lines; The temperature variation area between the outer ring temperature line and the inner ring temperature line is filled by the outer ring temperature line and the inner ring temperature line and the wall thickness of the spindle (2), thereby obtaining a spindle temperature profile; The spindle temperature profile is adjusted to a uniform ratio and input into the matching model, and the matching model outputs the vibration critical situation as an output result, that is, vibration is about to occur, or vibration will not occur.

7. The turning, milling and grinding monitoring composite CNC machine tool according to claim 6, characterized in that: The method comprises receiving a plurality of temperature signals and estimating the temperature of the outer ring of the main shaft (2) at any position in the axial direction, converting the temperature of the outer ring of the main shaft (2) at any position in the axial direction into a line expressing the temperature change in color, and obtaining the outer ring temperature line, including the following steps: A one-dimensional steady-state heat conduction equation is used to describe the temperature distribution of the outer ring of the main shaft (2) in the axial direction, and boundary conditions are set; According to the heat conduction equation and boundary conditions, the temperature distribution can be discretized using the finite difference method; Use polynomial interpolation to calculate the temperature at any axial position; Obtaining temperature data of each position of the outer ring of the main shaft (2) in the axial direction, and determining the coordinates of each position; Normalizing the temperature data of each position of the outer ring of the main shaft (2) in the axial direction to obtain a normalized temperature; Use the normalized temperature to map it to a color space and get the color value corresponding to each temperature; For two adjacent positions and the corresponding color values, the color at any position is calculated by linear interpolation to obtain the outer circle temperature line.

8. The turning, milling and grinding monitoring composite CNC machine tool according to claim 7, characterized in that: The method comprises receiving a plurality of inner circle thermal maps of the main shaft (2) and converting them into lines expressing temperature changes in colors to obtain inner circle temperature lines, including the following steps: Extracting the temperature data of the inner ring of the main shaft (2) from each heat map of the inner ring of the main shaft (2), setting the width of the heat map of the inner ring of the main shaft (2), and the height of the heat map of the inner ring of the main shaft (2), wherein each pixel in the heat map of the inner ring of the main shaft (2) represents the temperature of the inner ring of the main shaft (2) at the corresponding position; The number of the heat maps of the inner ring of the main shaft (2) and the range of the axial position are set, and each heat map of the inner ring of the main shaft (2) provides a temperature distribution at a corresponding position; Extracting temperature information of corresponding positions from each heat map of the inner ring of the main shaft (2), wherein the temperature data on each heat map of the inner ring of the main shaft (2) is a two-dimensional matrix; The axial position corresponding to each image and the temperature data at that position are known. For the temperature data in different images, axial interpolation is performed through spline interpolation to obtain the temperature distribution along the axial direction. For each axial position, the temperature value of the position is calculated using the interpolation method, and the obtained temperature data is a one-dimensional temperature distribution sequence; According to the calculated temperature distribution, the temperature values ​​are converted into colors using color mapping technology, and the temperature values ​​are matched with the colors to generate the inner circle temperature lines.

9. The turning, milling and grinding monitoring composite CNC machine tool according to claim 8, characterized in that: The method of filling the temperature variation region between the outer ring temperature line and the inner ring temperature line and the wall thickness of the spindle (2) to obtain a spindle temperature profile diagram comprises the following steps: For any point between the outer circle temperature line and the inner circle temperature line, the corresponding temperature is obtained by linear interpolation; Use temperature to color conversion and calculate the color at each position to form a spindle temperature profile.

10. The turning, milling and grinding monitoring composite CNC machine tool according to claim 1, characterized in that: The main shaft (2) is tubular, and the inner ring of the main shaft (2) is fixedly connected with a first inner blade (6) and a second inner blade (7), the pitch of the first inner blade (6) and the second inner blade (7) are arranged to be the same, and there is a spacing between the first inner blade (6) and the second inner blade (7) and the end of the main shaft (2), the width of the first inner blade (6) and the second inner blade (7) are both equal to the inner radius of the main shaft (2), and the first inner blade (6) and the second inner blade (7) are arranged to overlap in an offset manner.

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