Thermal compensation device and method for machine tool electric spindle and numerical control machine tool

Abstract

The application provides a thermal compensation device and method of a machine tool electric spindle and a numerical control machine tool, and the thermal compensation device comprises a displacement detection device and a control device, a detection part of the displacement detection device is arranged on a tool holder connected with the spindle, the detection part of the displacement detection device and a detection surface of the tool holder are arranged in a vertical direction, and the detection part of the displacement detection device is arranged opposite and parallel to the detection surface of the tool holder; the displacement detection device detects thermal displacement of the spindle in the vertical direction by detecting distance change between the detection part of the displacement detection device and the detection surface of the tool holder; the control device is connected with the displacement detection device, the control device is used for acquiring data detected by the displacement detection device, and the position of the spindle in the vertical direction is adaptively adjusted according to the data detected by the displacement detection device. The thermal compensation device of the machine tool electric spindle can effectively solve the technical problems of the thermal compensation device of the machine tool electric spindle in the prior art, such as complex structure and poor anti-interference ability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of machine tools, in particular to a thermal compensation device and method for an electric spindle of a machine tool and a numerical control machine tool. BACKGROUND

[0002] In the machining process of a numerical control machine tool, various factors interfere with the machining process, and the most important factor is temperature change. During the operation of the machine tool, factors such as power consumption, mechanical friction and environmental temperature cause the generation of heat, thereby causing the temperature of the machine tool to change constantly, affecting the accuracy and stability of the machine tool. As a core component of a numerical control machine tool, an electric spindle is directly related to the machining accuracy and efficiency. However, the thermal displacement that occurs during the machining of the electric spindle is mainly reflected in the front end of the tool holder, and the tool holder drives the tool to produce upward or downward thermal displacement in the Z-axis direction, thereby affecting the machining accuracy of the workpiece surface. Therefore, it is particularly important to compensate for the thermal error of the spindle of the machine tool.

[0003] At present, there are mainly two ways to reduce the thermal error of the electric spindle: thermal error suppression method and thermal error compensation method. The thermal error suppression method relies on improving the structural design of the numerical control machine tool or directly controlling the temperature to reduce the thermal error. This method can reduce the temperature rise of the heat source, balance the temperature rise and reduce the thermal deformation of the numerical control machining device to a certain extent, but it will increase the cost of structural design and manufacturing. The thermal error compensation method is to analyze and model the error estimation of the numerical control machine tool, and then use different methods to appropriately compensate, eliminate or reduce the error of the system, which is an effective and economical means to improve the machining accuracy of the numerical control machine tool. Therefore, this thermal error compensation method has become an important research field in modern precision engineering at home and abroad.

[0004] However, the existing thermal error compensation device is mainly realized by temperature sensors and position sensors, and the temperature sensors and position sensors of the thermal error compensation device are arranged in a parallel manner. Therefore, each temperature sensor and position sensor must be connected to the acquisition controller through a separate connection line, resulting in complex wiring after connecting multiple temperature sensors, multiple position sensors and the acquisition control unit. In addition, since the temperature sensor of the thermal error compensation technology uses a thermal resistor or a thermocouple, the output electric signal is weak, thereby reducing the anti-interference ability of the thermal error compensation device and the robustness and universality of the error compensation model.

[0005] Therefore, the existing technology needs to be further developed. SUMMARY

[0006] The present application aims to overcome the above technical deficiencies and provide a thermal compensation device and method for an electric spindle of a machine tool and a numerical control machine tool to solve the technical problems of the existing thermal compensation device for an electric spindle of a machine tool, complex structure and poor anti-interference ability.

[0007] To achieve the above-mentioned technical objectives, according to one aspect of the present invention: a thermal compensation device for a machine tool electric spindle is provided, comprising: a displacement detection device and a control device; the detection part of the displacement detection device is disposed on a tool holder connected to the spindle, the detection part of the displacement detection device and the detection surface of the tool holder are spaced apart in the vertical direction, and the detection part of the displacement detection device and the detection surface of the tool holder are opposite to and parallel to each other; the displacement detection device detects the thermal displacement of the spindle in the vertical direction by detecting the change in distance between the detection part of the displacement detection device and the detection surface of the tool holder; the control device is connected to the displacement detection device, and the control device is used to acquire the data detected by the displacement detection device, and to adaptively adjust the position of the spindle in the vertical direction according to the data detected by the displacement detection device, so as to achieve error compensation.

[0008] Furthermore, the thermal compensation device also includes: a fixing device, which is movably mounted on the tool holder in the vertical direction; the mounting surface of the fixing device is arranged opposite to the detection surface of the tool holder; the detection part of the displacement detection device is mounted on the mounting surface of the fixing device, so as to adjust the initial distance between the detection part of the displacement detection device and the detection surface of the tool holder by moving the fixing device in the vertical direction.

[0009] Furthermore, the mounting surface of the fixing device has a through hole and at least one mounting groove. The through hole extends vertically, and its axis is parallel to the axis of the tool holder. The fixing device is fitted onto the tool holder through the through hole. At least one mounting groove is spaced apart from the through hole, and at least one mounting groove is opposite to the detection surface of the tool holder. The displacement detection device includes at least one coil, which forms the detection part of the displacement detection device. The coil and the mounting groove are arranged in a one-to-one correspondence, and the coil is installed in the corresponding mounting groove. The coil is opposite to and parallel to the detection surface of the tool holder.

[0010] Furthermore, the thermal compensation device also includes: a potting material, which is poured into the mounting groove to fix the coil in the corresponding mounting groove; and / or, the tool holder includes a tool holder body and a positioning ring, the positioning ring being sleeved on the tool holder body, the positioning ring being coaxially arranged with the tool holder body and the spindle respectively, and the bottom end face of the positioning ring forming the detection surface of the tool holder; the cross-section of the mounting groove is circular, the distance from the axis of the through hole to the edge of the mounting groove is less than the outer diameter of the positioning ring; the wall thickness of the positioning ring is greater than the outer diameter of the coil.

[0011] Furthermore, the side wall of the fixing device is provided with at least one wire outlet hole, which is respectively set with a mounting groove and a coil, and the wire outlet hole is connected to the corresponding mounting groove; the displacement detection device also includes: at least one signal line, which is set with a coil, one end of the signal line is connected to the corresponding coil, and the other end of the signal line passes through the mounting groove and the wire outlet hole in sequence and is located on the outside of the fixing device; the processor is connected to the end of the signal line away from the corresponding coil, and the processor receives the data detected by the corresponding coil through the signal line; the processor is used to process the data detected by the coil.

[0012] Furthermore, the electric spindle of the machine tool includes a spindle assembly and a spindle, the spindle assembly having a placement cavity, at least a portion of the spindle being rotatably disposed within the placement cavity; the thermal compensation device further includes: a support device mounted on the spindle assembly; the support device is connected to a fixing device, and the fixing device is movably disposed relative to the support device.

[0013] Furthermore, the support device includes: a first support frame and a second support frame, which are mounted on the shaft assembly. The first and second support frames are located on opposite sides of the fixing device and are arranged opposite to each other. The thermal compensation device also includes: a first connecting rod and a second connecting rod, which are coaxially arranged. The first and second connecting rods are vertically adjustable and mounted on the first and second support frames, respectively. The ends of the first and second connecting rods away from the first and second support frames are detachably connected to the fixing device. This allows the fixing device to move vertically when the positions of the first and second connecting rods relative to the first and second support frames are adjusted.

[0014] Furthermore, the first support frame is provided with a plurality of first mounting holes, which are spaced apart vertically; the second support frame is provided with a plurality of second mounting holes, which are spaced apart vertically; each first mounting hole and each second mounting hole are provided in a one-to-one correspondence; wherein, the end of the first connecting rod away from the fixing device passes through any one of the first mounting holes; the end of the second connecting rod away from the fixing device passes through the corresponding second mounting hole, so that the fixing device is connected to the first support frame and the second support frame respectively.

[0015] Furthermore, the first support frame has a first mounting portion and a first connecting portion, the first mounting portion being connected to the first connecting portion and the first connecting portion being located below the first mounting portion; the first mounting portion is used for fixed connection with the shaft assembly; the first connecting portion extends vertically and has a plurality of first mounting holes, each of the first mounting holes being spaced apart along the extending direction of the first connecting portion; the second support frame has a second mounting portion and a second connecting portion, the second mounting portion being connected to the second connecting portion and the second connecting portion being located below the second mounting portion; the second mounting portion is used for fixed connection with the shaft assembly; the second connecting portion extends vertically and has a plurality of second mounting holes, each of the second mounting holes being spaced apart along the extending direction of the second connecting portion; the first connecting portion and the second connecting portion are arranged opposite to each other.

[0016] According to another aspect of the present invention, a CNC machine tool is provided, comprising the above-described thermal compensation device.

[0017] According to another aspect of the present invention, a thermal compensation method is provided, which is applied to the aforementioned thermal compensation device; the thermal compensation method includes: determining the initial output voltage of the displacement detection device before the machine tool is run. After the machine tool starts running, obtain the current output voltage of the displacement detection device. Based on the current output voltage of the displacement detection device and the initial output voltage of the displacement detection device The position of the spindle in the vertical direction is adjusted adaptively to achieve error compensation; where n is the number of detections by the displacement detection device, and n≥1.

[0018] Furthermore, based on the current output voltage of the displacement detection device and the initial output voltage of the displacement detection device A method for adaptively adjusting the spindle's vertical position to achieve error compensation includes: calculating the current output voltage. With initial output voltage First voltage difference ; to the absolute value of the first voltage difference Sensitivity of displacement detection device Compare and based on the first voltage difference Determine the error compensation direction of the spindle in the vertical direction; based on the absolute value of the first voltage difference. Sensitivity of displacement detection device Based on the comparison results and the determined error compensation direction, the position of the spindle in the vertical direction is adjusted; among which, the sensitivity of the displacement detection device... The unit is .

[0019] Furthermore, based on the absolute value of the first voltage difference Sensitivity of displacement detection device Based on the comparison results and the determined error compensation direction, the method for adjusting the position of the spindle in the vertical direction includes: when 1. When the error compensation direction of the spindle is determined to be vertically upward, control the spindle to move upward 1. ;when 1. When the error compensation direction of the spindle is determined to be vertically downward, control the spindle to move downward. .

[0020] Furthermore, based on the first voltage difference A method for determining the error compensation direction of the spindle in the vertical direction includes: based on a first voltage difference. Determine the direction of thermal displacement of the spindle; based on the direction of thermal displacement of the spindle, determine the error compensation direction of the spindle in the vertical direction; when the direction of thermal displacement of the spindle is vertically upward, determine the error compensation direction of the spindle in the vertical direction as vertically downward; when the direction of thermal displacement of the spindle is vertically downward, determine the error compensation direction of the spindle in the vertical direction as vertically upward.

[0021] Furthermore, based on the first voltage difference Methods for determining the direction of thermal displacement of the spindle include: when At that time, the thermal displacement direction of the spindle is vertically upward; when At that time, the thermal displacement direction of the spindle is vertically downward.

[0022] Furthermore, the thermal compensation method also includes: determining whether the spindle speed is switching; and when the spindle speed is switching, calculating the next output voltage of the displacement detection device. Current output voltage of the displacement detection device The second voltage difference ; based on the second voltage difference Determine whether to output the next voltage of the displacement detection device. As the new initial output voltage of the displacement detection device When the next output voltage of the displacement detection device is... As the new initial output voltage of the displacement detection device At that time, the new initial output voltage will be... Using the reference voltage, the thermal displacement detection of the spindle is restarted, and error compensation is performed on the spindle based on the detection results.

[0023] Furthermore, based on the second voltage difference Determine whether to output the next voltage of the displacement detection device. As the new initial output voltage of the displacement detection device The method includes: to convert the second voltage difference With preset threshold Compare; when At that time, the next output voltage of the displacement detection device will be... As the new initial output voltage of the displacement detection device .

[0024] Beneficial effects:

[0025] Applying the technical solution of this invention, the thermal compensation device for a machine tool electric spindle provided by this invention includes: a displacement detection device and a control device. The displacement detection device has a detection part, which is disposed on a tool holder connected to the spindle. The detection part of the displacement detection device and the detection surface of the tool holder are arranged vertically at intervals, and the detection part of the displacement detection device is located below the detection surface of the tool holder. Furthermore, the detection part of the displacement detection device and the detection surface of the tool holder are opposite to and parallel to each other. The displacement detection device detects the thermal displacement of the spindle in the vertical direction by measuring the change in distance between its detection part and the detection surface of the tool holder. The control device is connected to the displacement detection device. The displacement detection device transmits the detected data to the control device. The control device adaptively adjusts the position of the spindle in the vertical direction according to the data detected by the displacement detection device, thereby achieving error compensation. Therefore, by using the displacement detection device to detect the thermal displacement of the spindle in the vertical direction in real time, and by using the control device to adjust the position of the spindle in a timely manner based on the detection data, real-time compensation for the thermal displacement of the spindle can be achieved. This mechanism ensures the tool remains in the correct position, significantly reducing machining errors caused by temperature changes, improving workpiece surface finish, and shortening machine tool warm-up time, allowing the machine to enter machining mode faster and saving time and costs. Simultaneously, real-time compensation for spindle thermal displacement reduces excessive wear and mechanical stress caused by thermal expansion, extending equipment lifespan and reducing downtime and rework due to thermal displacement, thus improving overall production efficiency. Furthermore, by detecting spindle thermal displacement through a displacement detection device, the thermal compensation device reduces unnecessary components and connections, resulting in a simpler overall structure. Mounting the displacement detection device on the tool holder facilitates installation and debugging, shortening equipment uptime and simplifying later maintenance. The device can also be flexibly configured to meet the needs of different machine tools, improving its adaptability and scalability. In addition, setting the detection part of the displacement detection device parallel to the detection surface of the tool holder allows for accurate measurement of the vertical distance between them, enabling real-time monitoring of spindle thermal displacement. This design reduces errors caused by improper installation angles, ensuring measurement reliability. Direct connection between the control device and the displacement detection device reduces signal transmission complexity and the possibility of electromagnetic interference or noise during transmission. The control device acquires data from the displacement detection device in real time, enabling the system to react quickly and adjust according to the actual thermal displacement, further enhancing its anti-interference capability. Furthermore, the control device can adapt to changes in various operating conditions, improving the flexibility and accuracy of system operation. The thermal compensation device for the machine tool electric spindle of this invention effectively solves the technical problems of complex structure and poor anti-interference capability in existing machine tool electric spindle thermal compensation devices. Attached Figure Description

[0026] Figure 1A schematic diagram of an embodiment of the thermal compensation device for the machine tool electric spindle of the present invention is shown;

[0027] Figure 2 A first-view structural schematic diagram of the fixing device in an embodiment of the thermal compensation device for the machine tool electric spindle of the present invention is shown;

[0028] Figure 3 A second-view structural schematic diagram of the fixing device in an embodiment of the thermal compensation device for the machine tool electric spindle of the present invention is shown;

[0029] Figure 4 A schematic diagram of the structure of the first support frame in an embodiment of the thermal compensation device for the machine tool electric spindle of the present invention is shown;

[0030] Figure 5 A schematic diagram of the structure of the second support frame in an embodiment of the thermal compensation device for the machine tool electric spindle of the present invention is shown;

[0031] Figure 6 A schematic diagram of the tool holder structure in an embodiment of the thermal compensation device for the machine tool electric spindle of the present invention is shown;

[0032] Figure 7 A schematic diagram of the processor structure in an embodiment of the thermal compensation device for the machine tool electric spindle of the present invention is shown;

[0033] Figure 8 A schematic diagram of a structure in which the processor is disposed on the electric spindle in an embodiment of the thermal compensation device for the machine tool electric spindle of the present invention is shown;

[0034] Figure 9 A flowchart illustrating an embodiment of the thermal compensation method of the present invention is shown;

[0035] Figure 10 A graph showing the relationship between the displacement of the displacement detection device and the output voltage of the displacement detection device in an embodiment of the thermal compensation method of the present invention is illustrated.

[0036] The above figures include the following reference numerals:

[0037] 1. Displacement detection device; 11. Coil; 12. Processor; 121. Placement chamber; 2. Fixing device; 20. Mounting surface; 21. Through hole; 22. Mounting groove; 23. Outlet hole; 24. Adjustment groove; 25. Connection hole; 3. Support device; 31. First support frame; 310. First mounting hole; 311. First mounting part; 312. First connecting part; 313. First opening groove; 32. Second support frame; 320. Second mounting hole; 321. Second mounting part; 322. Second connecting part; 323. Second opening groove; 4. First connecting rod; 5. Second connecting rod; 100. Tool holder; 101. Detection surface; 102. Tool holder body; 103. Positioning ring; 200. Shaft assembly; 201. First shaft; 202. Second shaft; 203. Flange; 300. Electric spindle. Detailed Implementation

[0038] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present application.

[0039] Please see Figures 1 to 8 As shown in the embodiment of the present invention, the present invention provides a thermal compensation device for a machine tool electric spindle, comprising: a displacement detection device 1 and a control device. The detection part of the displacement detection device 1 is disposed on a tool holder 100 connected to the spindle. The detection part of the displacement detection device 1 and the detection surface 101 of the tool holder 100 are arranged at intervals in the vertical direction, and the detection part of the displacement detection device 1 and the detection surface 101 of the tool holder 100 are opposite to and parallel to each other. The displacement detection device 1 detects the thermal displacement of the spindle in the vertical direction by detecting the change in distance between the detection part of the displacement detection device 1 and the detection surface 101 of the tool holder 100. The control device is connected to the displacement detection device 1 and is used to acquire the data detected by the displacement detection device 1 and to adaptively adjust the position of the spindle in the vertical direction according to the data detected by the displacement detection device 1 to achieve error compensation.

[0040] As can be seen, the thermal compensation device for the machine tool electric spindle provided by the present invention includes: a displacement detection device 1 and a control device. The displacement detection device 1 has a detection part, which is disposed on a tool holder 100 connected to the spindle. The detection part of the displacement detection device 1 and the detection surface 101 of the tool holder 100 are arranged vertically at intervals, and the detection part of the displacement detection device 1 is located below the detection surface of the tool holder 100. Furthermore, the detection part of the displacement detection device 1 and the detection surface 101 of the tool holder 100 are opposite to and parallel to each other. The displacement detection device 1 detects the thermal displacement of the spindle in the vertical direction by measuring the change in distance between its detection part and the detection surface 101 of the tool holder 100. The control device is connected to the displacement detection device 1. The displacement detection device 1 transmits the detected data to the control device. The control device adaptively adjusts the position of the spindle in the vertical direction according to the data detected by the displacement detection device 1, thereby achieving error compensation.

[0041] Therefore, by using the displacement detection device 1 to detect the spindle's thermal displacement in the vertical direction in real time, and by adjusting the spindle position promptly based on the detection data through the control device, real-time compensation for the spindle's thermal displacement can be achieved. This mechanism ensures that the tool remains in the correct position, thereby significantly reducing machining errors caused by temperature changes, improving workpiece surface machining accuracy, and shortening the machine tool's warm-up time, allowing the machine tool to enter the machining state more quickly and saving time costs. Simultaneously, real-time compensation for the spindle's thermal displacement can also reduce excessive wear and mechanical stress caused by thermal expansion, thereby extending the equipment's service life and reducing downtime and rework caused by thermal displacement, improving overall production efficiency. Furthermore, by using the displacement detection device 1 to detect the spindle's thermal displacement, the thermal compensation device reduces unnecessary components and connections, making the overall structure simpler. Mounting the displacement detection device 1 on the tool holder 100 facilitates installation and debugging, shortens equipment uptime, and facilitates later maintenance. Moreover, the device can be flexibly configured according to the needs of different machine tools, improving its adaptability and scalability. Furthermore, by arranging the detection part of the displacement detection device 1 parallel to the detection surface 101 of the tool holder 100, the vertical distance between them can be accurately measured, thereby enabling real-time monitoring of the spindle's thermal displacement. This design reduces errors caused by improper installation angles and ensures measurement reliability. Direct connection between the control device and the displacement detection device 1 reduces the complexity of signal transmission and lowers the possibility of electromagnetic interference or noise during transmission. By acquiring data from the displacement detection device in real time, the control device enables the system to react quickly and adjust according to the actual thermal displacement, further enhancing its anti-interference capability. In addition, the control device can adapt to changes under various operating conditions, improving the flexibility and accuracy of system operation. The thermal compensation device for the machine tool electric spindle of this invention effectively solves the technical problems of complex structure and poor anti-interference capability in existing machine tool electric spindle thermal compensation devices.

[0042] Optionally, the displacement detection device 1 is a displacement sensor, preferably an eddy current displacement sensor.

[0043] Optionally, the detection surface 101 of the tool holder 100 is a flat end face of the tool holder 100, and the edge of the detection part of the displacement detection device 1 is located inside the edge of the detection surface 101 of the tool holder 100, so that the edge of the detection part of the displacement detection device 1 cannot protrude from the edge of the detection surface 101 of the tool holder 100.

[0044] Furthermore, the detection surface of the tool holder 100 is located above the detection section of the displacement detection device 1.

[0045] Optionally, the control device is a programmable logic controller (PLC).

[0046] Optionally, the spindle can be understood as the axis of the electric spindle of the machine tool. The tool holder 100 is rotated by rotating the spindle.

[0047] Specifically, such as Figures 1 to 3 As shown, the thermal compensation device further includes: a fixing device 2, which is movably mounted on the tool holder 100 in the vertical direction; the mounting surface 20 of the fixing device 2 is positioned opposite to the detection surface 101 of the tool holder 100; the detection part of the displacement detection device 1 is mounted on the mounting surface 20 of the fixing device 2, so that the initial distance between the detection part of the displacement detection device 1 and the detection surface 101 of the tool holder 100 can be adjusted by moving the fixing device 2 in the vertical direction. With this structural arrangement, the detection part of the displacement detection device 1 can be mounted on the tool holder 100 by the fixing device 2. The fixing device 2 is movable relative to the tool holder 100 in the vertical direction, thereby adjusting the initial distance between the detection part of the displacement detection device 1 and the detection surface 101 of the tool holder 100. This design reduces the time and complexity required for initial calibration and improves work efficiency. At the same time, the mobility of the fixing device 2 allows the device to adapt to tools of different lengths and types, providing greater flexibility and versatility. Furthermore, by precisely adjusting the initial distance, measurement errors caused by external factors (such as vibration or temperature changes) can be reduced, thereby providing a more stable working environment.

[0048] Furthermore, the mounting surface 20 of the fixing device 2 is in a horizontal state, and the mounting surface 20 of the fixing device 2 and the detection surface 101 of the tool holder 100 are distributed parallel to each other.

[0049] Optionally, when adjusting the initial distance between the detection part of the displacement detection device 1 and the detection surface 101 of the tool holder 100, the fixing device 2 reciprocates in the vertical direction. After the adjustment is completed, the fixing device 2 will remain stationary.

[0050] Specifically, such asFigure 2 and Figure 3 As shown, the mounting surface 20 of the fixing device 2 has a through hole 21 and at least one mounting groove 22. The through hole 21 extends vertically, and its axis is parallel to the axis of the tool holder 100. The fixing device 2 is fitted onto the tool holder 100 through the through hole 21. The at least one mounting groove 22 is spaced apart from the through hole 21 and is opposite to the detection surface 101 of the tool holder 100. The displacement detection device 1 includes at least one coil 11, which forms the detection part of the displacement detection device 1. The coil 11 is correspondingly arranged with the mounting groove 22, and the coil 11 is installed in the corresponding mounting groove 22. The coil 11 is opposite to and parallel to the detection surface 101 of the tool holder 100. With this structure, the through hole 21 facilitates the fixing device 2 being fitted onto the tool holder 100, and the mounting groove 22, which corresponds to the coil 11, facilitates the installation of the coil 11 in the corresponding mounting groove 22, thereby ensuring the accuracy of the coil 11's position. In addition, the coil 11 is parallel to and opposite to the detection surface 101 of the tool holder 100, which can ensure the accuracy of detection and prevent detection errors.

[0051] Optionally, there are multiple mounting slots 22, which are evenly spaced around the circumferential direction of the through hole 21. There are multiple coils 11, which are arranged in a one-to-one correspondence with the multiple mounting slots 22.

[0052] Furthermore, the fixing device 2 has a symmetrical structure and a central line of symmetry. The central line of symmetry of the fixing device 2 is parallel to both the axis of the spindle and the axis of the tool holder 100. The axis of the through hole 21 coincides with the central line of symmetry of the fixing device 2.

[0053] Optionally, the axis of the through hole 21 is aligned with the axis of the tool holder 100, and the diameter of the through hole 21 is larger than the diameter of the tool holder body 102 of the tool holder 100. In this way, when the tool holder 100 rotates with the spindle, the through hole 21 can provide clearance for the tool holder 100, thereby effectively preventing interference and friction.

[0054] Specifically, the thermal compensation device also includes a potting material, which is poured into the mounting groove 22 to fix the coil 11 within the corresponding mounting groove 22. This structural arrangement effectively fixes the coil 11 within the mounting groove 22, ensuring its stable position and reducing displacement caused by vibration or mechanical movement. The application of the potting material improves the coil 11's impact and wear resistance, extending the equipment's service life. Furthermore, potting reduces the contact between the coil 11 and the external environment, thereby minimizing the impact of moisture, dust, and other contaminants on detection accuracy.

[0055] Optionally, the potting material is epoxy resin.

[0056] Specifically, such as Figure 2 , Figure 3 and Figure 6 As shown, the tool holder 100 includes a tool holder body 102 and a positioning ring 103. The positioning ring 103 is sleeved on the tool holder body 102 and is coaxially arranged with both the tool holder body 102 and the spindle. The bottom end face of the positioning ring 103 forms the detection surface 101 of the tool holder 100. The cross-section of the mounting groove 22 is circular, and the distance from the axis of the through hole 21 to the edge of the mounting groove 22 is less than the outer diameter of the positioning ring 103. The wall thickness of the positioning ring 103 (see attached diagram) is... Figure 6 In this design, D1 (the wall thickness of the positioning ring 103) is greater than the outer diameter of the coil 11. This structural arrangement ensures that the positioning ring 103 is coaxially aligned with the tool holder body 102 and the spindle, guaranteeing precise alignment between the tool and the spindle. This coaxial design effectively reduces vibration and deviation during machining, improving machining accuracy. The bottom surface of the positioning ring 103 forms the detection surface 101 of the tool holder 100, providing a stable and reliable reference surface, thus ensuring the consistency and reliability of the detection surface 101 and avoiding measurement errors caused by surface unevenness. Furthermore, the distance from the axis of the through hole 21 to the edge of the mounting groove 22 is designed to be less than the outer diameter of the positioning ring 103, ensuring that each mounting groove 22 is located inside the edge of the detection surface 101, preventing the edge of the coil 11 from protruding beyond the edge of the detection surface 101. This design reduces external interference and noise, improving the stability of signal acquisition. Meanwhile, the wall thickness of the positioning ring 103 is greater than the outer diameter of the coil 11, thereby further ensuring that the coil 11 is always located inside the edge of the detection surface 101, thus eliminating the adverse effects of edge effects on the output signals of each coil 11. This improves the detection accuracy of the displacement detection device 1.

[0057] Optionally, the wall thickness of the positioning ring 103 should be greater than three times the outer diameter of the coil 11.

[0058] Specifically, such as Figure 2 , Figure 7 and Figure 8As shown, the side wall of the fixing device 2 is provided with at least one wire outlet hole 23, which is respectively arranged in a one-to-one correspondence with the mounting groove 22 and the coil 11, and the wire outlet hole 23 is connected to the corresponding mounting groove 22. The displacement detection device 1 also includes: at least one signal line and a processor 12. The signal line is arranged in a one-to-one correspondence with the coil 11. One end of the signal line is connected to the corresponding coil 11, and the other end of the signal line passes through the mounting groove 22 and the wire outlet hole 23 in sequence and is located on the outside of the fixing device 2. The processor 12 is connected to the end of the signal line away from the corresponding coil 11. The processor 12 can receive the data detected by the corresponding coil 11 through the signal line. The processor 12 is used to process the data detected by the coil 11. With this structural arrangement, the wire outlet hole 23 is located on the side wall of the fixing device 2, so that the signal line can pass through the mounting groove 22 and the wire outlet hole 23 in an orderly manner, avoiding the problem of messy cables, thereby improving the neatness of the device and facilitating management and maintenance. The processor 12 receives data detected by the corresponding coil 11 through the signal line, and then the processor 12 can quickly process the received data and adjust the position of the spindle as needed to achieve error compensation, thereby improving the response speed of the device.

[0059] Furthermore, one end of each signal line located outside the mounting device 2 is connected to the processor 12 via an aviation socket.

[0060] Furthermore, such as Figure 8 and Figure 9 As shown, the processor 12 includes a placement chamber 121 and a circuit board. The circuit board is located inside the placement chamber 121 to protect it. The circuit board is connected to each coil 11 via signal lines. The circuit board receives signals detected by each coil 11, amplifies and processes the signals detected by each coil 11, and finally obtains the distance between the detected part and the detected surface, thereby detecting the thermal displacement of the spindle. The detected result is then transmitted to the control device.

[0061] Furthermore, the processor 12 is disposed on the side wall of the shaft assembly 200.

[0062] Furthermore, the mounting surface 20 of the fixing device 2 is provided with an adjustment groove 24, which corresponds one-to-one with the mounting groove 22. The adjustment groove 24 is connected to the corresponding mounting groove 22 and the wire outlet hole 23, and the adjustment groove 24 is located on the side of the mounting groove 22 away from the through hole 21. After one end of the signal line is connected to the corresponding coil 11, the other end of the signal line passes through the mounting groove 22, the adjustment groove 24 and the wire outlet hole in sequence and is connected to the processor 12. By setting the adjustment groove 24, the position of the corresponding signal line and coil 11 output end and input end can be adjusted within the adjustment groove 24, and the corresponding signal line and coil 11 output end and input end can be fixed by the adjustment groove 24. In addition, it also facilitates the installation and subsequent maintenance of the signal line and coil 11.

[0063] Specifically, such as Figure 1 As shown, the electric spindle 300 of the machine tool includes a spindle assembly 200 and a spindle. The spindle assembly 200 has a placement cavity, and at least a portion of the spindle is rotatably disposed within the placement cavity. The thermal compensation device also includes a support device 3, which is mounted on the spindle assembly 200. The support device 3 is connected to a fixing device 2, and the fixing device 2 is movably disposed relative to the support device 3. This structural arrangement, with the support device 3 mounted on the spindle assembly 200, provides stable mechanical support for the fixing device 2. This stable support reduces errors caused by vibration during machining, improving the stability and reliability of the system. Simultaneously, the movable disposal of the fixing device 2 relative to the support device 3 allows for flexible adjustment of the fixing device 2's position according to actual needs, ensuring its accurate position relative to the tool holder 100, and thus determining the position of the detection part of the displacement detection device 1 relative to the detection surface 101. This design also avoids interference from the fixing device 2 with the tool holder, ensuring smooth machining.

[0064] Optionally, both the fixing device 2 and the supporting device 3 are made of materials with low thermal expansion and good rigidity, such as steel or ceramic materials. Using such materials minimizes the thermal displacement of the fixing device 2 and the supporting device 3 during spindle rotation.

[0065] Specifically, such as Figure 1 , Figure 4 and Figure 5As shown, the support device 3 includes a first support frame 31 and a second support frame 32, which are mounted on the shaft assembly 200. The first support frame 31 and the second support frame 32 are located on opposite sides of the fixing device 2 and are arranged opposite to each other. The thermal compensation device also includes a first connecting rod 4 and a second connecting rod 5, which are coaxially arranged and vertically adjustable on the first support frame 31 and the second support frame 32, respectively. The end of the first connecting rod 4 away from the first support frame 31 and the end of the second connecting rod 5 away from the second support frame 32 are detachably connected to the fixing device 2. This allows the fixing device 2 to move vertically when the position of the first connecting rod 4 relative to the first support frame 31 and the position of the second connecting rod 5 relative to the second support frame 32 are adjusted. With this structural arrangement, the first support frame 31 and the second support frame 32 are mounted on the shaft assembly 200, providing stable mechanical support for the entire thermal compensation device. This improves the stability and reliability of the system. The first link 4 and the second link 5 are coaxially arranged, ensuring smooth and symmetrical movement of the fixing device 2 in the vertical direction. This coaxial design ensures that the fixing device 2 will not skew during movement, maintaining high-precision displacement detection. Simultaneously, the first link 4 and the second link 5 are adjustablely mounted vertically on the first support frame 31 and the second support frame 32, allowing for flexible adjustment of the height of the fixing device 2. This design ensures that the distance between the detection part of the displacement detection device 1 and the detection surface 101 is adjusted to a preset value. Furthermore, both the first link 4 and the second link 5 are detachably connected to the fixing device 2, facilitating easy replacement and installation of the fixing device 2 according to actual needs, thereby reducing maintenance difficulty and cost.

[0066] Furthermore, the fixing device 2 is provided with two connecting holes 25, which are spaced apart on the side wall of the fixing device 2 and are arranged opposite to each other. Both connecting holes 25 are provided with internal threads. The end of the first connecting rod 4 near the fixing device 2 and the end of the second connecting rod 5 near the fixing device 2 are provided with external threads that are compatible with the internal threads, so as to connect the first connecting rod 4 and the second connecting rod 5 to the fixing device 2 detachably through threaded connection.

[0067] Specifically, such as Figure 1 , Figure 4 and Figure 5As shown, the first support frame 31 has multiple first mounting holes 310, which are spaced apart vertically; the second support frame 32 has multiple second mounting holes 320, which are also spaced apart vertically; each first mounting hole 310 corresponds to each second mounting hole 320; a first connecting rod 4, with its end away from the fixing device 2, passes through any one of the first mounting holes 310; a second connecting rod 5, with its end away from the fixing device 2, passes through the corresponding second mounting hole 320, connecting the fixing device 2 to the first support frame 31 and the second support frame 32 respectively. This structural arrangement, with multiple first mounting holes 310 and second mounting holes 320 spaced apart vertically, provides multiple height selection points. Users can select appropriate first mounting holes 310 and second mounting holes 320 to connect according to actual needs, achieving precise height adjustment. Each first mounting hole 310 corresponds one-to-one with each second mounting hole 320, ensuring that the mounting surface of the fixing device 2 is horizontally aligned with the detection surface, and guaranteeing that the fixing device 2 will not tilt during movement, maintaining high-precision displacement detection. Since multiple mounting holes are available, the height of the fixing device 2 can be optimized by simply selecting a suitable mounting hole during initial calibration. This flexibility makes the calibration process simpler and faster, reducing the time and complexity of initial setup. When it is necessary to replace or repair the fixing device 2 or its components, the fixing device 2 can be easily disassembled and reinstalled by removing the first connecting rod 4 and the second connecting rod 5, reducing maintenance difficulty and cost.

[0068] Specifically, such as Figure 1 , Figure 4 and Figure 5As shown, the first support frame 31 has a first mounting portion 311 and a first connecting portion 312. The first mounting portion 311 is connected to the first connecting portion 312, and the first connecting portion 312 is located below the first mounting portion 311. The first mounting portion 311 is used for fixed connection with the shaft assembly 200. The first connecting portion 312 extends in a vertical direction and has a plurality of first mounting holes 310, which are spaced apart along the extending direction of the first connecting portion 312. The second support frame 32 has... A second mounting portion 321 and a second connecting portion 322 are connected, with the second mounting portion 321 located below the second mounting portion 321. The second mounting portion 321 is used for fixed connection with the shaft assembly 200. The second connecting portion 322 extends vertically and has multiple second mounting holes 320 spaced apart along its extension direction. A first connecting portion 312 is positioned opposite to the second connecting portion 322. This structural arrangement ensures the stability of the entire support device by fixing the first mounting portion 311 and the second mounting portion 321 to the shaft assembly 200, reducing displacement caused by vibration or external forces. The multiple vertically spaced first mounting holes 310 and second mounting holes 320 on the first connecting portion 312 and the second connecting portion 322 provide multiple height selection points for the fixing device 2, enabling precise height adjustment.

[0069] Furthermore, the shaft assembly 200 includes a first shaft 201 and a second shaft 202, the first shaft 201 being connected to the second shaft 202 via a flange 203 to form a placement cavity for at least a portion of the spindle. A first support frame 31 and a second support frame 32 are mounted on the flange 203.

[0070] Optionally, the placement cavity has a symmetrical structure and a central symmetry line, which is coaxial with the axis of the main shaft.

[0071] Furthermore, such as Figure 4 As shown, the first mounting portion 311 extends along a preset direction, and the extension direction of the first mounting portion 311 is perpendicular to the extension direction of the first connecting portion 312. The first mounting portion 311 has a first opening groove 313, which extends along the extension direction of the first mounting portion 311. The thermal compensation device also includes a first fastener, the limiting end of which is located below the first mounting portion 311, and the connecting portion of which passes through the first opening groove 313. When the first support frame 31 is mounted on the flange 203 using the first fastener placed in the first opening groove 313, the limiting end of the first fastener abuts against the bottom surface of the first mounting portion 311.

[0072] Furthermore, such asFigure 5 As shown, the second mounting portion 321 extends along a preset direction, and the extension direction of the second mounting portion 321 is perpendicular to the extension direction of the second connecting portion 322. The second mounting portion 321 is provided with a second opening groove 323, which extends along the extension direction of the second mounting portion 321. The thermal compensation device also includes a second fastener, the limiting end of which is located below the second mounting portion 321, and the connecting portion of which passes through the second opening groove 323. When the second support frame 32 is mounted on the flange 203 using the second fastener placed in the second opening groove 323, the limiting end of the second fastener abuts against the bottom surface of the second mounting portion 321.

[0073] Optionally, the process of adjusting the distance between the detection part of the displacement detection device 1 and the detection surface 101 is as follows:

[0074] First, each coil 11 is installed on the fixing device 2, and each coil 11 is connected to the processor. At the same time, the first support frame 31 and the second support frame 32 are installed on the flange 203. The first support frame 31 and the second support frame 32 are located on both sides of the tool holder 100, and the first connecting part 312 of the first support frame 31 and the second connecting part 322 of the second support frame 32 are arranged opposite to each other.

[0075] Next, the fixing device 2 is fitted onto the tool holder body 102 of the tool holder 100 through the through hole 21. Then, the displacement detection device 1 is activated, and the fixing device 2 is moved vertically. The position of the detection part of the displacement detection device 1 relative to the detection surface 101 is adjusted based on the data detected by the displacement detection device 1. When the output voltage corresponding to the distance between the detection part of the displacement detection device 1 and the detection surface 101 reaches a set value, the first connecting rod 4 and the second connecting rod 5 pass through the corresponding first mounting hole 310 and second mounting hole 320 respectively and connect to the fixing device 2, fixing the fixing device 2 in that position, which is the initial installation position. This completes the adjustment work. The output voltage corresponding to this distance is used as a reference voltage for subsequent detection of the spindle's thermal displacement.

[0076] This invention provides a CNC machine tool, characterized by including: the thermal compensation device of the above embodiment. With this structural arrangement, the beneficial effects of the thermal compensation device on the CNC machine tool are the same as those achieved by the thermal compensation device in the above embodiment, and will not be elaborated further here.

[0077] This invention provides a thermal compensation method, which is applied to the aforementioned thermal compensation device; such as Figure 9 As shown, thermal compensation methods include:

[0078] S11. Before running the machine tool, determine the initial output voltage of the displacement detection device 1. .

[0079] S12. After the machine tool starts running, obtain the current output voltage of the displacement detection device 1. .

[0080] S13, based on the current output voltage of displacement detection device 1 and the initial output voltage of displacement detection device 1 The position of the spindle in the vertical direction is adaptively adjusted to achieve error compensation. Here, n represents the number of detections performed by the displacement detection device 1, where n ≥ 1.

[0081] Using this control method, the initial output voltage of the displacement detection device 1 is determined before the machine tool starts operating. This provides a benchmark for subsequent error compensation. After the machine tool starts running, the current output voltage of the displacement detection device 1 is acquired in real time. It can monitor the thermal expansion of the spindle in real time. This is based on the current output voltage of the displacement detection device 1. and the initial output voltage of displacement detection device 1 By adaptively adjusting the spindle position in the vertical direction, dynamic error compensation is achieved, ensuring the tool remains in the correct position. This significantly reduces machining errors caused by temperature changes, improves workpiece surface finish, and shortens machine tool warm-up time, allowing the machine to enter machining mode more quickly and saving time costs. Furthermore, by adjusting the spindle position in real time, vibration and instability caused by thermal expansion are reduced, ensuring stability during machining and further reducing machining errors. This is achieved by adjusting the current output voltage of the displacement detection device 1. and the initial output voltage of displacement detection device 1 By adaptively adjusting the vertical position of the spindle, precise error compensation is achieved. This method not only enhances the stability and reliability of the system but also simplifies the operation process and improves the system's flexibility and efficiency.

[0082] like Figure 10 As shown, the eddy current displacement sensor has a range of 500 micrometers, corresponding to an output voltage of 0-10V. The distance between the detection part of the displacement detection device 1 and the detection surface 101 is adjusted by moving the fixing device 2 vertically. This distance is made less than the range of the eddy current displacement sensor, while simultaneously ensuring that the output voltage corresponding to this distance reaches a preset value. When the output voltage reaches the preset value, the fixing device 2 is fixed at that position, and this output voltage is used as the initial output voltage of the displacement detection device 1. For example, when the range of the eddy current displacement sensor is 500 micrometers, the distance between the detection part of the displacement detection device 1 and the detection surface 101 is adjusted to 250 micrometers to determine the initial output voltage of the displacement detection device 1. It is 5V.

[0083] To further ensure the accuracy of thermal compensation, the current output voltage of displacement detection device 1 is determined. The process employed a multi-coil collaborative detection and data processing method. The specific steps are as follows:

[0084] Signal acquisition: When there are multiple coils 11, the signals detected by each coil 11 are sent to the processor 12.

[0085] Signal processing: The processor 12 processes the signal detected by each coil 11 and converts it into a corresponding voltage signal.

[0086] Data fusion: Processor 12 calculates the average value of the voltage signals of all coils 11 as the current output voltage. .

[0087] This method not only improves the accuracy and reliability of the detection data, but also enhances the system's anti-interference ability, ensuring the high precision and stability of the spindle thermal compensation.

[0088] Specifically, based on the current output voltage of displacement detection device 1 and the initial output voltage of displacement detection device 1 A method for adaptively adjusting the spindle's vertical position to achieve error compensation includes: calculating the current output voltage. With initial output voltage First voltage difference ; to the absolute value of the first voltage difference Sensitivity of displacement detection device 1 Compare and based on the first voltage difference Determine the error compensation direction of the spindle in the vertical direction; based on the absolute value of the first voltage difference. Sensitivity of displacement detection device 1 Based on the comparison results and the determined error compensation direction, the position of the main shaft in the vertical direction is adjusted; among which, the sensitivity of the displacement detection device 1 is... The unit is Using this control method, the current output voltage is... With initial output voltage First voltage difference Sensitivity of displacement detection device 1 By comparing the two systems, micron-level thermal compensation can be achieved, enabling efficient and precise spindle thermal displacement compensation, thereby improving workpiece surface finish and shortening machine tool warm-up time. Furthermore, continuous voltage data acquisition during processing ensures the timeliness and accuracy of compensation.

[0089] Among them, the sensitivity of displacement detection device 1 This refers to the sensitivity of the eddy current displacement sensor. Sensitivity indicates the device's (i.e., the eddy current displacement sensor's) ability to respond to a unit change in displacement; specifically, it's the change in the output signal (e.g., voltage) caused by each unit change in displacement. Its unit is typically "voltage / displacement," for example... Sensitivity reflects the accuracy with which a displacement detection device senses and responds to minute changes in displacement.

[0090] Specifically, based on the absolute value of the first voltage difference Sensitivity of displacement detection device 1 Based on the comparison results and the determined error compensation direction, the method for adjusting the position of the spindle in the vertical direction includes: when 1. When the error compensation direction of the spindle is determined to be vertically upward, control the spindle to move upward 1. ;when 1. When the error compensation direction of the spindle is determined to be vertically downward, control the spindle to move downward. This control method, by precisely based on the absolute value of the first voltage difference... Sensitivity of displacement detection device By comparing the results of the number of inspections and combining them with the determined error compensation direction, the vertical position of the spindle can be adjusted to accurately compensate for deviations in the vertical direction. This ensures that the spindle is in an ideal position as much as possible during machining, thereby improving the dimensional and shape accuracy of the machined workpiece and guaranteeing machining quality.

[0091] Where n is the number of times the displacement detection device 1 performs the detection, and n≥1.

[0092] Optionally, the thermal compensation method in this embodiment uses an arithmetic sequence for compensation.

[0093] Specifically, based on the first voltage difference A method for determining the error compensation direction of the spindle in the vertical direction includes: based on a first voltage difference. The system determines the direction of the spindle's thermal displacement; based on this direction, it determines the vertical error compensation direction for the spindle. When the spindle's thermal displacement direction is vertically upward, the vertical error compensation direction is determined to be vertically downward; when the spindle's thermal displacement direction is vertically downward, the vertical error compensation direction is determined to be vertically upward. This control method, based on the first voltage difference... It can accurately determine the error compensation direction of the spindle, thereby enabling precise displacement compensation.

[0094] Specifically, based on the first voltage difference Methods for determining the direction of thermal displacement of the spindle include: when At that time, the thermal displacement direction of the spindle is vertically upward; when At this time, the thermal displacement direction of the spindle is vertically downward. Using this control method, the direction of thermal displacement can be accurately determined, ensuring the correct direction of error compensation, avoiding error accumulation caused by reverse compensation, and further improving machining accuracy.

[0095] Optionally, from Figure 10 As can be seen from the displacement amount and output voltage of the displacement detection device 1 shown, the larger the displacement amount, the larger the corresponding output voltage of the displacement detection device 1. The detection part of the displacement detection device 1 is located below the detection surface 101. Therefore, when the distance between the detection part of the displacement detection device 1 and the detection surface 101 increases, the current output voltage of the displacement detection device 1... It will grow bigger at this time. The value should be positive, and it can be determined that the thermal displacement direction of the spindle is vertically upward. Therefore, it is necessary to control the spindle to move downward in order to achieve error compensation. Similarly, when the distance between the detection part of the displacement detection device 1 and the detection surface 101 decreases, the current output voltage of the displacement detection device 1... It will become smaller at this time. It should be a negative value, and it can be determined that the thermal displacement direction of the spindle is vertically downward. Therefore, it is necessary to control the spindle to move upward in order to achieve error compensation.

[0096] Specifically, the thermal compensation method also includes: determining whether the spindle speed is switching; and when the spindle speed is switching, calculating the next output voltage of the displacement detection device 1. The current output voltage of displacement detection device 1 The second voltage difference ; based on the second voltage difference Determine whether to output the next voltage of displacement detection device 1. As the new initial output voltage of displacement detection device 1 When the next output voltage of displacement detection device 1 is... As the new initial output voltage of displacement detection device 1 At that time, the new initial output voltage will be... Using the reference voltage, the spindle thermal displacement detection restarts, and error compensation is performed on the spindle based on the detection results. This control method ensures that the system updates the initial output voltage promptly when the spindle speed changes, guaranteeing that subsequent thermal displacement detection is based on the latest reference voltage, thus avoiding error accumulation caused by speed changes. By monitoring the spindle speed in real time and dynamically adjusting the reference voltage, the system can better adapt to speed changes while maintaining high-precision machining capabilities. This thermal compensation method achieves full-speed thermal displacement compensation, is suitable for various complex working conditions, and significantly improves machining accuracy and system reliability.

[0097] Optionally, the output voltage of the displacement detection device may experience a step change when the spindle speed changes. For example, when the spindle switches from 6000 RPM to 12000 RPM, the current output voltage is 5.14V, while the next output voltage drops to 5.10V. This indicates that the spindle has undergone significant vertical downward thermal displacement. In this case, to perform error compensation, the system needs to wait for the output voltage to rise back to 5.14V before compensation can be performed. This results in a significant time delay in error compensation, making it impossible to correct thermal displacement in real time, potentially affecting machining accuracy. Furthermore, delayed compensation may cause brief interruptions in the machining process, thus affecting overall production efficiency and continuity. However, by updating the reference voltage immediately upon detecting a significant step change using the method described above, subsequent thermal displacement detection can be ensured to be based on the latest reference point, reducing compensation delay.

[0098] Specifically, based on the second voltage difference Determine whether to output the next voltage of displacement detection device 1. As the new initial output voltage of displacement detection device 1 The method includes: to convert the second voltage difference With preset threshold Compare; when At that time, the next output voltage of displacement detection device 1 will be... As the new initial output voltage of displacement detection device 1 Using this control method, the second voltage difference... With preset threshold By comparing the reference voltage with the initial output voltage, subsequent measurements can be performed based on a more accurate reference. This method effectively reduces measurement errors caused by reference deviations, significantly improving measurement accuracy and reliability. Dynamically adjusting the reference voltage avoids measurement errors caused by accumulated reference deviations, thus improving the overall system's measurement accuracy.

[0099] Optionally, the specific steps of the thermal compensation method are as follows:

[0100] The sensitivity of displacement detection device 1 is 14 mv / μm.

[0101] Step 1: Before running the machine tool, adjust the distance between the detection part of the displacement detection device 1 and the detection surface 101 to move the detection part of the displacement detection device 1 to the initial installation position, and the displacement detection device 1 collects the output voltage corresponding to this initial installation position. Determine this output voltage as the initial output voltage of the displacement detection device 1. .

[0102] Step 2: After the machine tool starts running and the spindle rotates, the displacement detection device 1 continuously collects the output voltage at a sampling rate of 2000 voltage values ​​per second. Simultaneously, it records the current output voltage. With initial output voltage The comparison is performed to detect whether the spindle has experienced thermal displacement, and based on the current output voltage. With initial output voltage First voltage difference Determine the error compensation direction of the spindle in the vertical direction.

[0103] The specific comparison process is as follows:

[0104] Step 21, when When the thermal displacement direction of the spindle is vertically upward, the error compensation direction of the spindle is determined to be vertically downward; when When the thermal displacement direction of the spindle is vertically downward, the error compensation direction of the spindle is determined to be vertically upward. Simultaneously, it is determined that... Is it greater than or equal to 1?

[0105] Step 22, if When the value is greater than or equal to 1, the spindle is controlled to move upward or downward according to the determined spindle error compensation direction. .like When the value is greater than or equal to 1, the spindle is controlled to move upward or downward according to the determined spindle error compensation direction. And so on, if When the value is greater than or equal to 1, the spindle is controlled to move upward or downward. .

[0106] When the spindle is operating normally, if the thermal displacement direction generated by the spindle is vertically downward, the subsequent thermal displacement direction of the spindle will also be vertically downward. Conversely, the same applies. Simultaneously, when the determined error compensation direction of the spindle is vertically upward, the circuit board of displacement detection device 1 sends a high-level pulse signal to the PLC, and the PLC controls the spindle to move upward. When the determined error compensation direction of the spindle is vertically downward, the circuit board of displacement detection device 1 sends a low-level pulse signal to the PLC, and the PLC controls the spindle to move downward.

[0107] Step 23: During the error compensation process, the counting module of the thermal compensation device will accumulate the number of detections by the displacement detection device 1.

[0108] Step 3: During the spindle rotation, the spindle speed is monitored in real time. When the spindle speed changes, the output voltage of the displacement detection device 1 changes abruptly. At this time, the next output voltage of the displacement detection device 1 is determined. The current output voltage of displacement detection device 1 The second voltage difference Is it greater than or equal to the preset threshold? If it is greater than 1, then the next output voltage of displacement detection device 1 will be adjusted. As the new initial output voltage of displacement detection device 1 At this point, the detection count n of the displacement detection device 1 in the counting module is reset to 1. The subsequent output voltage counts of the displacement detection device 1 start from 1, thus beginning a new round of arithmetic sequence compensation.

[0109] Step 4: When the machine tool finishes processing, the displacement detection device 1 cuts off the power and is in the off state.

[0110] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0111] Optionally, specific examples in this embodiment can refer to the examples described in the above embodiments, and will not be repeated here.

[0112] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0113] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0114] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A thermal compensation device for a machine tool electric spindle, characterized in that, include: A displacement detection device (1) is provided, wherein the detection part of the displacement detection device (1) is disposed on a tool holder (100) connected to the spindle, the detection part of the displacement detection device (1) and the detection surface (101) of the tool holder (100) are arranged at intervals in the vertical direction, and the detection part of the displacement detection device (1) and the detection surface (101) of the tool holder (100) are opposite to and parallel to each other; the displacement detection device (1) detects the thermal displacement of the spindle in the vertical direction by detecting the change in distance between the detection part of the displacement detection device (1) and the detection surface (101) of the tool holder (100); A control device is connected to the displacement detection device (1). The control device is used to acquire the data detected by the displacement detection device (1) and to adaptively adjust the position of the main shaft in the vertical direction according to the data detected by the displacement detection device (1) to achieve error compensation. A fixing device (2) is movably mounted on the tool holder (100) along the vertical direction; the mounting surface (20) of the fixing device (2) is opposite to the detection surface (101) of the tool holder (100); the detection part of the displacement detection device (1) is mounted on the mounting surface (20) of the fixing device (2) so that the initial distance between the detection part of the displacement detection device (1) and the detection surface (101) of the tool holder (100) can be adjusted by moving the fixing device (2) along the vertical direction; The electric spindle (300) of the machine tool includes: a spindle assembly (200) and the spindle, wherein the spindle assembly (200) has a placement cavity, and at least a portion of the spindle is rotatably disposed in the placement cavity; the thermal compensation device further includes: a support device (3), which is mounted on the spindle assembly (200); the support device (3) is connected to the fixing device (2), and the fixing device (2) is movably disposed relative to the support device (3); the support device (3) includes: a first support frame (31) and a second support frame (32), which are mounted on the spindle assembly (200), and are respectively located on both sides of the fixing device (2), and are disposed opposite to each other; The first link (4) and the second link (5) are coaxially arranged. The first link (4) and the second link (5) are respectively adjustablely mounted on the first support frame (31) and the second support frame (32) along the vertical direction. The end of the first link (4) away from the first support frame (31) and the end of the second link (5) away from the second support frame (32) are detachably connected to the fixing device (2). When the position of the first link (4) relative to the first support frame (31) and the position of the second link (5) relative to the second support frame (32) are adjusted, the fixing device (2) is moved along the vertical direction.

2. The thermal compensation device according to claim 1, characterized in that, The mounting surface (20) of the fixing device (2) is provided with a through hole (21) and at least one mounting groove (22). The through hole (21) extends along the vertical direction, and the axis of the through hole (21) is arranged parallel to the axis of the tool holder (100). The fixing device (2) is sleeved on the tool holder (100) through the through hole (21). At least one mounting groove (22) is spaced apart from the through hole (21), and at least one mounting groove (22) is arranged opposite to the detection surface (101) of the tool holder (100). The displacement detection device (1) includes at least one coil (11), and at least one coil (11) forms the detection part of the displacement detection device (1); the coil (11) is arranged in a one-to-one correspondence with the mounting groove (22), and the coil (11) is installed in the corresponding mounting groove (22); the coil (11) is opposite to and parallel to the detection surface (101) of the tool holder (100).

3. The thermal compensation device according to claim 2, characterized in that, The thermal compensation device further includes: a potting material, which is poured into the mounting groove (22) to fix the coil (11) in the corresponding mounting groove (22); and / or, The tool holder (100) includes a tool holder body (102) and a positioning ring (103). The positioning ring (103) is sleeved on the tool holder body (102). The positioning ring (103) is coaxially arranged with the tool holder body (102) and the main shaft respectively. The bottom end face of the positioning ring (103) forms the detection surface (101) of the tool holder (100). The cross-section of the mounting groove (22) is circular. The distance from the axis of the through hole (21) to the edge of the mounting groove (22) is less than the outer diameter of the positioning ring (103). The wall thickness of the positioning ring (103) is greater than the outer diameter of the coil (11).

4. The thermal compensation device according to claim 2, characterized in that, The fixing device (2) has at least one wire outlet hole (23) on its side wall. The wire outlet hole (23) is respectively provided with one-to-one correspondence between the mounting groove (22) and the coil (11), and the wire outlet hole (23) is connected to the corresponding mounting groove (22); the displacement detection device (1) further includes: At least one signal line is provided, which is arranged in a one-to-one correspondence with the coil (11). One end of the signal line is connected to the corresponding coil (11), and the other end of the signal line passes through the mounting groove (22) and the wire outlet (23) in sequence and is located outside the fixing device (2). A processor (12) is connected to one end of the signal line away from the corresponding coil (11), the processor (12) receiving data detected by the corresponding coil (11) via the signal line; the processor (12) is used to process the data detected by the coil (11).

5. The thermal compensation device according to claim 1, characterized in that, The first support frame (31) is provided with a plurality of first mounting holes (310), and each of the first mounting holes (310) is spaced apart in the vertical direction; the second support frame (32) is provided with a plurality of second mounting holes (320), and each of the second mounting holes (320) is spaced apart in the vertical direction; each of the first mounting holes (310) and each of the second mounting holes (320) are provided in a one-to-one correspondence; The first connecting rod (4) is inserted through one end away from the fixing device (2) into any one of the first mounting holes (310); the second connecting rod (5) is inserted through one end away from the fixing device (2) into the corresponding second mounting hole (320), so that the fixing device (2) is connected to the first support frame (31) and the second support frame (32) respectively.

6. The thermal compensation device according to claim 5, characterized in that, The first support frame (31) has a first mounting portion (311) and a first connecting portion (312), the first mounting portion (311) is connected to the first connecting portion (312), and the first connecting portion (312) is located below the first mounting portion (311); the first mounting portion (311) is used for fixed connection with the shaft assembly (200); the first connecting portion (312) extends along the vertical direction, and the first connecting portion (312) is provided with a plurality of first mounting holes (310), and each first mounting hole (310) is spaced apart along the extending direction of the first connecting portion (312); The second support frame (32) has a second mounting portion (321) and a second connecting portion (322), the second mounting portion (321) is connected to the second connecting portion (322), and the second connecting portion (322) is located below the second mounting portion (321); the second mounting portion (321) is used for fixed connection with the shaft assembly (200); the second connecting portion (322) extends along the vertical direction, and the second connecting portion (322) is provided with a plurality of second mounting holes (320), each of the second mounting holes (320) being spaced apart along the extension direction of the second connecting portion (322); the first connecting portion (312) is disposed opposite to the second connecting portion (322).

7. A CNC machine tool, characterized in that, include: The thermal compensation device according to any one of claims 1 to 6.

8. A thermal compensation method, characterized in that, The thermal compensation method is applied to the thermal compensation device according to any one of claims 1 to 6; the thermal compensation method includes: Before running the machine tool, determine the initial output voltage of the displacement detection device (1). ; After the machine tool is running, the current output voltage of the displacement detection device (1) is obtained. ; Based on the current output voltage of the displacement detection device (1) and the initial output voltage of the displacement detection device (1) The position of the spindle in the vertical direction is adaptively adjusted to achieve error compensation. Where n is the number of times the displacement detection device (1) detects, and n≥1.

9. The thermal compensation method according to claim 8, characterized in that, The current output voltage of the displacement detection device (1) is used as the basis. and the initial output voltage of the displacement detection device (1) A method for adaptively adjusting the position of the spindle in the vertical direction to achieve error compensation includes: Calculate the current output voltage With the initial output voltage First voltage difference ; The absolute value of the first voltage difference The sensitivity of the displacement detection device (1) Compare and based on the first voltage difference Determine the error compensation direction of the main shaft in the vertical direction; Based on the absolute value of the first voltage difference The sensitivity of the displacement detection device (1) Based on the comparison results and the determined error compensation direction, the position of the main shaft in the vertical direction is adjusted; The sensitivity of the displacement detection device (1) is as follows. The unit is .

10. The thermal compensation method according to claim 9, characterized in that, The absolute value of the first voltage difference The sensitivity of the displacement detection device (1) Based on the comparison results and the determined error compensation direction, a method for adjusting the position of the spindle in the vertical direction includes: when 1. When the error compensation direction of the spindle is determined to be vertically upward, control the spindle to move upward 1. ; when 1. When the error compensation direction of the spindle is determined to be vertically downward, control the spindle to move downward 1. .

11. The thermal compensation method according to claim 9, characterized in that, The first voltage difference A method for determining the error compensation direction of the spindle in the vertical direction includes: Based on the first voltage difference Determine the direction of thermal displacement of the spindle; The error compensation direction of the spindle in the vertical direction is determined based on the thermal displacement direction of the spindle. When the thermal displacement direction of the spindle is vertically upward, the error compensation direction of the spindle in the vertical direction is determined to be vertically downward. When the thermal displacement direction of the spindle is vertically downward, the error compensation direction of the spindle in the vertical direction is determined to be vertically upward.

12. The thermal compensation method according to claim 11, characterized in that, The first voltage difference The method for determining the thermal displacement direction of the spindle includes: when At that time, the thermal displacement direction of the main shaft is vertically upward; when At that time, the thermal displacement direction of the main shaft is vertically downward.

13. The thermal compensation method according to claim 8, characterized in that, The thermal compensation method further includes: Determine whether the spindle speed needs to be switched; When the spindle speed changes, the next output voltage of the displacement detection device (1) is calculated. The current output voltage of the displacement detection device (1) The second voltage difference ; Based on the second voltage difference Determine whether to adjust the next output voltage of the displacement detection device (1). As the new initial output voltage of the displacement detection device (1) ; When the next output voltage of the displacement detection device (1) is... As the new initial output voltage of the displacement detection device (1) At that time, the new initial output voltage will be... Using the reference voltage, the thermal displacement detection of the spindle is restarted, and error compensation is performed on the spindle based on the detection results.

14. The thermal compensation method according to claim 13, characterized in that, The second voltage difference Determine whether to adjust the next output voltage of the displacement detection device (1). As the new initial output voltage of the displacement detection device (1) The methods include: To make the second voltage difference With preset threshold Compare; when At that time, the next output voltage of the displacement detection device (1) will be... As the new initial output voltage of the displacement detection device (1) .

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