Vertical liquid suspension electric spindle

Abstract

The embodiment of the invention relates to the technical field of machine tool spindles, and discloses a vertical liquid suspension electric spindle, a rolling bearing and a liquid suspension bearing are arranged at the two ends of the spindle respectively, the spindle can be supported only through the rolling bearing in a low-speed operation state, and when a sensor detects that the vibration amplitude of the spindle exceeds a normal range, the spindle is driven to rotate. If the main shaft runs, the rolling bearing is abraded or the machining precision cannot meet the requirement for the running speed of the current main shaft, then the liquid suspension bearing is controlled to start to work to conduct liquid suspension supporting on the main shaft, and therefore the supporting mode is flexibly switched according to the running state of the main shaft to ensure efficient and stable running of the main shaft. In the liquid suspension supporting process of the main shaft, the oil inlet flow of the oil inlet hole of the liquid suspension bearing is smaller than or equal to the oil outlet flow of the oil outlet hole; the operation stability of the main shaft is further improved; and the service life of the liquid suspension bearing is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of machine tool spindles, and in particular to a vertical liquid suspended electric spindle. Background Art

[0002] Traditional machine tool electric spindles are usually supported by rolling bearings, and rolling bearings are widely used in mechanical equipment. However, due to the sliding friction between the rolling element and the cage, the contact between the rolling element and the inner and outer ring raceways is often non-pure rolling, which can cause problems such as heating, wear, and vibration, limiting the further increase of movement speed to ultra-high speed. At the same time, the rolling element and the inner and outer ring raceways are mostly point and line rigid contacts, which can cause problems such as excessive local stress and internal and external vibration transmission, making it difficult for manufacturing equipment using rolling bearings to break through the limits of micron / submicron machining accuracy. In addition, rolling bearings have the problem of wear and tear and need to be replaced regularly, which not only increases maintenance costs, but may also affect the continuous operation and machining accuracy of machine tools. Summary of the invention

[0003] The main purpose of the present invention is to provide a vertical liquid suspended electric spindle, aiming to solve the technical problems in the prior art that the rolling bearings of the electric spindles of machine tools cannot meet the high-speed operation of the spindle and the maintenance cost is high.

[0004] To achieve the above-mentioned purpose, an embodiment of the present application provides a vertical liquid suspended electric spindle, comprising: A casing, wherein the casing is provided with an oil inlet hole and an oil outlet hole; A drive assembly disposed in the housing, the drive assembly comprising a stator coil frame, a stator coil disposed on the stator coil frame, and a main shaft disposed in the stator coil frame; A rolling bearing assembly, the rolling bearing assembly comprising a first rolling bearing and a second rolling bearing disposed at opposite ends of the main shaft, the rolling bearing assembly being configured to support the main shaft; A vibration detection sensor is disposed on a side close to the output end of the spindle and is configured to monitor the vibration state of the spindle; A liquid suspension bearing assembly, the liquid suspension bearing assembly comprising a first liquid suspension bearing and a second liquid suspension bearing disposed at opposite ends of the main shaft, the first liquid suspension bearing being disposed on the outside of the first rolling bearing, the second liquid suspension bearing being disposed on the outside of the second rolling bearing, the liquid suspension bearing assembly being configured to suspend and support the main shaft when the vibration detection sensor detects that the vibration amplitude of the main shaft exceeds a preset vibration amplitude; Among them, the first liquid suspension bearing and / or the second liquid suspension bearing include a flexible oil film and a wear-resistant buffer layer arranged on the inner layer of the flexible oil film, one end of the flexible oil film is connected to the oil inlet hole, and the other end is connected to the oil outlet hole; when the liquid suspension bearing assembly is in a state of suspending and supporting the main shaft, the oil inlet flow rate of the oil inlet hole is less than or equal to the oil outlet flow rate of the oil outlet hole.

[0005] In a possible implementation, a pressure relief hole is further provided on the housing, and the first liquid suspension bearing and / or the second liquid suspension bearing further includes a pressure valve provided in the flexible oil film, and the pressure valve is communicated with the pressure relief hole.

[0006] In a possible implementation, the first rolling bearing is arranged on a side close to the output end of the main shaft, and the first rolling bearing includes a first inner rolling bearing and a first outer rolling bearing arranged at intervals along the length direction of the main shaft, and the distance between the vibration detection sensor and the first inner rolling bearing is greater than or equal to twice the distance between the first inner rolling bearing and the first outer rolling bearing.

[0007] In a possible implementation, the housing includes a main housing and a first shell and a second shell detachably connected to the main housing, the first shell is configured to seal and protect the first liquid suspension bearing, and the second shell is configured to seal and protect the second liquid suspension bearing.

[0008] In a possible implementation, the vibration detection sensor includes at least an acceleration sensor along a first direction and an acceleration sensor along a second direction, the first direction and the second direction are perpendicular to each other, and the first direction and the second direction are both perpendicular to the vertical direction; and / or, The outer side surface of the main shaft is also provided with a stepless adjustment slide rail, and the vibration detection sensor is arranged on the stepless adjustment slide rail and has a slidable state and a locked state.

[0009] In a possible implementation, the outer side surface of the main shaft is provided with a preloaded inclined surface, and the liquid suspension bearing assembly is sleeved on the preloaded inclined surface; and / or, The main shaft is a hollow structure, and cooling liquid is provided in the hollow cavity of the main shaft at corresponding positions of the first liquid suspension bearing and / or the second liquid suspension bearing.

[0010] In a possible implementation, the preload bevel includes a first preload bevel and a second preload bevel, and the first preload bevel and the second preload bevel provide opposite preload forces to the liquid suspension bearing assembly.

[0011] In a possible implementation, the device further includes a processor, wherein the processor is configured to control the liquid suspension bearing assembly according to the vibration monitoring data of the vibration detection sensor, and the processor performs the following control method steps: Acquire vibration monitoring data sensed by the vibration detection sensor, wherein the vibration monitoring data includes vibration acceleration in a first direction and vibration acceleration in a second direction, wherein the first direction and the second direction are perpendicular to each other, and both the first direction and the second direction are perpendicular to a vertical direction; In response to the vibration acceleration in the first direction having acceleration in positive and negative directions and the absolute value of the acceleration being greater than or equal to an acceleration threshold, and / or in response to the vibration acceleration in the second direction having acceleration in positive and negative directions and the absolute value of the acceleration being greater than or equal to the acceleration threshold, the oil pump is controlled to operate so that the liquid suspension bearing assembly performs suspension support on the main shaft.

[0012] In a possible implementation, a pressure sensor is further provided in the flexible oil film, the processor is further configured to control the thickness of the oil cavity according to pressure sensing data of the pressure sensor, and the processor further performs the following control method steps: Acquiring pressure monitoring data of the pressure sensor, wherein the pressure monitoring data includes a liquid pressure value in the flexible oil film; When the liquid pressure value in the flexible oil film is greater than the pressure threshold range, the oil pump is controlled to reduce the oil injection speed to reduce the thickness of the oil chamber. When the liquid pressure value in the flexible oil film is less than the pressure threshold, the oil pump is controlled to increase the oil injection speed to increase the thickness of the oil chamber.

[0013] In a possible implementation, a temperature sensor is provided on the spindle, and the processor is further configured to control the oil inlet and oil outlet according to the temperature value sensed by the temperature sensor, and the processor further performs the following control method steps: Acquiring sensing data of the temperature sensor to obtain a measured temperature value of the spindle; The measured temperature value of the spindle is input into the oil quantity adjustment model to obtain the difference between the oil inlet and the oil outlet. The oil quantity adjustment model satisfies the following expression: Q in =Q out -1.028 (T-25) (T ≥ 25 °C), where Q in is the oil flow rate of the oil inlet hole, Q out is the oil flow rate of the oil outlet, and T is the measured temperature value during the operation of the spindle.

[0014] Different from the prior art, the embodiment of the present application provides a vertical liquid suspension electric spindle, in which rolling bearings and liquid suspension bearings are respectively arranged at both ends of the spindle. The spindle can be supported only by rolling bearings in the low-speed operation state. When the sensor detects that the vibration amplitude of the spindle exceeds the normal range, it means that the rolling bearing is worn or the processing accuracy cannot meet the current spindle operation speed requirement. At this time, the liquid suspension bearing is controlled to start working to support the spindle by liquid suspension. In this way, the support mode is flexibly switched according to the operation state of the spindle to ensure the efficient and stable operation of the spindle. In addition, during the process of liquid suspension support of the spindle, the oil inlet flow rate of the oil inlet hole of the liquid suspension bearing is less than or equal to the oil outlet flow rate of the oil outlet hole; in this way, through fine flow control, the heat generated during the operation of the spindle can be prevented from having an adverse effect on the oil chamber thickness of the liquid suspension bearing, which not only further improves the stability of the spindle operation, but also prolongs the service life of the liquid suspension bearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0016] Figure 1 A cross-sectional view of a vertical liquid-suspended electric spindle in some embodiments of the present application; Figure 2 This is a schematic diagram of the three-dimensional structure of a vertical liquid-suspended electric spindle in some embodiments of the present application; Figure 3 This is a schematic diagram of the structure of a liquid suspension bearing of a vertical liquid suspension electric spindle in some embodiments of the present application; Figure 4 This is a schematic diagram of the spindle structure of a vertical liquid-suspended electric spindle in some embodiments of the present application; Figure 5 This is a flowchart of a processor control method for a vertical liquid suspended electric spindle in some embodiments of the present application; Figure 6 Schematic diagram of the flow chart of the processor control method of the vertical liquid suspended electric spindle in other embodiments of the present application.

[0017] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0020] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, "and / or" in the full text includes three solutions. Taking A and / or B as an example, it includes technical solution A, technical solution B, and technical solution that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0021] Traditional machine tool electric spindles are usually supported by rolling bearings, and rolling bearings are widely used in mechanical equipment. However, due to the sliding friction between the rolling element and the cage, the contact between the rolling element and the inner and outer ring raceways is often non-pure rolling, which can cause problems such as heating, wear, and vibration, limiting the further increase of movement speed to ultra-high speed. At the same time, the rolling element and the inner and outer ring raceways are mostly point and line rigid contacts, which can cause problems such as excessive local stress and internal and external vibration transmission, making it difficult for manufacturing equipment using rolling bearings to break through the limits of micron / submicron machining accuracy. In addition, rolling bearings have the problem of wear and tear and need to be replaced regularly, which not only increases maintenance costs, but may also affect the continuous operation and machining accuracy of machine tools.

[0022] In response to the above problems, Figure 1-4 As shown, the present application proposes a vertical liquid suspended electric spindle, comprising: A housing 100, wherein the housing 100 is provided with an oil inlet 110 and an oil outlet 120; A driving assembly 200 disposed in the housing 100, the driving assembly 200 comprising a stator coil frame 210, a stator coil 220 disposed on the stator coil frame 210, and a main shaft 230 disposed in the stator coil frame 210; A rolling bearing assembly 300, wherein the rolling bearing assembly 300 includes a first rolling bearing 310 and a second rolling bearing 320 disposed at opposite ends of the main shaft 230, and the rolling bearing assembly 300 is configured to support the main shaft 230; A vibration detection sensor 400 is disposed on a side close to the output end of the main shaft 230 and is configured to monitor the vibration state of the main shaft 230; A liquid suspension bearing assembly 500, the liquid suspension bearing assembly 500 comprises a first liquid suspension bearing 510 and a second liquid suspension bearing 520 disposed at opposite ends of the main shaft 230, the first liquid suspension bearing 510 being disposed on the outside of the first rolling bearing 310, and the second liquid suspension bearing 520 being disposed on the outside of the second rolling bearing 320, the liquid suspension bearing assembly 500 being configured to suspend and support the main shaft 300 when the vibration detection sensor 400 detects that the vibration amplitude of the main shaft 230 exceeds a preset vibration amplitude; Among them, the first liquid suspension bearing 510 and / or the second liquid suspension bearing 520 include a flexible oil film 530 and a wear-resistant buffer layer 540 arranged on the inner layer of the flexible oil film 530, one end of the flexible oil film 530 is connected to the oil inlet hole 110, and the other end is connected to the oil outlet hole 120; when the liquid suspension bearing assembly 500 is in a suspended supporting state for the main shaft 300, the oil inlet flow rate of the oil inlet hole 110 is less than or equal to the oil outlet flow rate of the oil outlet hole 120.

[0023] Specifically, the housing 100 serves as the outer protective shell of the entire electric spindle. The housing 100 is designed with an oil inlet 110 and an oil outlet 120. The two holes are used to provide lubricating oil to the liquid suspension bearing assembly 500 and discharge the used lubricating oil, respectively, so as to ensure that the liquid suspension bearing assembly 500 maintains a stable filling state to stably support the spindle 230. The driving assembly 200 is located inside the housing 100, and includes a stator coil frame 210, a stator coil 220 and a spindle 230. The stator coil 220 is wound on the stator coil frame 210, and generates a magnetic field by energizing, driving the spindle 230 to rotate in the stator coil frame 210. The rolling bearing assembly 300 includes a first rolling bearing 310 and a second rolling bearing 320, which are respectively installed at opposite ends of the spindle 230 to support the spindle 230 and ensure that the spindle 230 remains stable during rotation. The vibration detection sensor 400 is installed near the output end of the main shaft 230, and is used to monitor the vibration state of the main shaft 230 in real time. When the vibration amplitude exceeds a preset value, the sensor will send a signal to trigger the start of the liquid suspension bearing assembly 500. The liquid suspension bearing assembly 500 includes a first liquid suspension bearing 510 and a second liquid suspension bearing 520, which are respectively located on the outside of the first rolling bearing 310 and the second rolling bearing 320. When the vibration detection sensor 400 detects that the main shaft 230 vibrates abnormally, the liquid suspension bearing assembly 500 starts to work and suspends and supports the main shaft 230.

[0024] When the main shaft 230 rotates normally, it is mainly supported by the rolling bearing assembly 300. At this time, the liquid suspension bearing assembly 500 is in a standby state, and the oil inlet hole 110 and the oil outlet hole 120 maintain a small amount of lubricating oil circulation (the amount of lubricating oil circulation is less than the amount of circulation in the start-up state of the liquid suspension bearing assembly 500) to maintain the wetness and lubrication performance of the flexible oil film 530. When the vibration detection sensor 400 detects that the vibration amplitude of the main shaft 230 exceeds the preset value, the system will determine that the rolling bearing 310 / 320 may have worn or the running speed of the main shaft 230 exceeds the accuracy range of the rolling bearing. At this time, the system will issue an instruction to start the liquid suspension bearing assembly 500. After receiving the start-up instruction, the liquid suspension bearing assembly 500 begins to inject lubricating oil into the flexible oil film 530 through the oil inlet hole 110. The flexible oil film 530 forms a thin oil film between the main shaft 230 and the bearing seat (arranged on the outer layer of the flexible oil film 530) to provide suspension support. Meanwhile, the used lubricating oil is discharged through the oil outlet 120 to keep the oil film clean and the temperature stable. The wear-resistant buffer layer 540 is made of wear-resistant rubber material and has stable wear-resistant performance.

[0025] In the liquid suspension support state, the system will accurately control the oil inlet flow rate of the oil inlet hole 110 and the oil outlet flow rate of the oil outlet hole 120 to ensure that the oil inlet flow rate is less than or equal to the oil outlet flow rate. In this way, the heat generated during the operation of the main shaft 230 is prevented from adversely affecting the oil film thickness, thereby maintaining the stability and reliability of the suspension support.

[0026] In order to reduce the adverse effects of temperature on the oil film thickness, thereby maintaining the stability and reliability of the suspension support, in one embodiment, the oil inlet and oil outlet can be controlled according to the temperature. The embodiment of the present application introduces a temperature-based regulation model to adjust the balance between the oil inlet and oil outlet.

[0027] The embodiment of the present application collects a large amount of data to train the adjustment model and calibrate the parameters to obtain the following model expression: Q in =Q out -1.028 (T-25), the unit of oil inlet flow rate and oil outlet flow rate is liter per second, where Q in represents the oil flow rate of the oil inlet hole 110, Q out represents the oil flow rate of the oil outlet hole 120, T represents the measured temperature during the operation of the spindle 230, and 25 represents the reference temperature (at a temperature of 25°C, the oil inlet and oil outlet reach a preset equilibrium state). When the spindle temperature rises (greater than 25°C), the temperature at the support of the flexible oil film 530 also rises. At this time, the flexible oil film 530 expands due to heat, so it is necessary to reduce the oil inlet flow rate to ensure the stability of the oil film thickness, thereby maintaining the stability and reliability of the suspension support. When one of the flow values ​​of the oil inlet flow rate or the oil outlet flow rate is known, the other flow value can be calculated according to the model formula.

[0028] Based on this, the vertical liquid suspended electric spindle provided in the embodiment of the present application, through the above-mentioned structural design and implementation process, can automatically switch to the liquid suspension support mode when the spindle vibrates abnormally, thereby ensuring the stable operation of the spindle and improving the reliability and service life of the equipment.

[0029] In one embodiment, a pressure relief hole 130 is further provided on the housing 100 , and the first liquid suspension bearing 510 and / or the second liquid suspension bearing 520 further includes a pressure valve 550 disposed in the flexible oil film 530 , and the pressure valve 550 is connected to the pressure relief hole 130 .

[0030] Specifically, the pressure relief hole 130 is an additional hole opened on the housing 100, which is used to allow excess lubricating oil or gas to be discharged when the pressure inside the liquid suspension bearing assembly 500 is too high, so as to prevent damage to the liquid suspension bearing or the main shaft. The pressure valve 550 is a component arranged inside the first liquid suspension bearing 510 and / or the second liquid suspension bearing 520, and is specifically arranged inside the flexible oil film 530. The function of the pressure valve 550 is to automatically open when the pressure inside the oil film reaches a preset threshold, allowing the lubricating oil or gas to be discharged through the pressure relief hole 130, thereby maintaining the stability of the pressure inside the oil film.

[0031] When the main shaft 230 rotates normally under the support of the liquid suspension bearing assembly 500, the flexible oil film 530 will form a stable lubricating support layer between the main shaft and the bearing seat. At this time, the pressure valve 550 is in a closed state, and the lubricating oil circulates inside the oil film to provide stable suspension support for the main shaft. When the internal pressure of the oil film exceeds the preset safety threshold, the pressure valve 550 is automatically triggered to open, and the excess lubricating oil or gas will be discharged to the outside of the housing 100 through the pressure valve 550 and the pressure relief hole 130. The pressure relief process will continue until the internal pressure of the oil film drops to a safe range. At this time, the pressure valve 550 will automatically close to prevent excessive loss of lubricating oil. After the pressure relief is completed, the liquid suspension bearing assembly 500 will return to the normal suspension support state and continue to provide stable support for the main shaft 230.

[0032] In one embodiment, the first rolling bearing 310 is arranged on a side close to the output end of the main shaft 230, and the first rolling bearing 310 includes a first inner rolling bearing 3110 and a first outer rolling bearing 3120 arranged at intervals along the length direction of the main shaft 230, and the distance between the vibration detection sensor 400 and the first inner rolling bearing 3110 is greater than or equal to twice the distance between the first inner rolling bearing 3110 and the first outer rolling bearing 3120.

[0033] Specifically, the first rolling bearing 310 includes two independent bearings spaced apart along the length direction of the main shaft 230, namely, the first inner rolling bearing 3110 and the first outer rolling bearing 3120. Such a design can provide better support effect and disperse the load on the main shaft. In the embodiment of the present application, the vibration detection sensor 400 is installed at a position a certain distance from the first inner rolling bearing 3110. That is, the distance between the vibration detection sensor 400 and the first inner rolling bearing 3110 is greater than or equal to twice the distance between the first inner rolling bearing 3110 and the first outer rolling bearing 3120. In this way, it can be ensured that the sensor can accurately detect the vibration of the main shaft at a position away from the direct support point, so as to more comprehensively evaluate the operating state of the main shaft. When the main shaft 230 starts to rotate, the vibration detection sensor 400 monitors the vibration state of the main shaft in real time. Since the sensor is installed at a position far away from the first inner rolling bearing 3110, it can capture vibration signals in a wider frequency range, including vibrations that may be caused by spindle imbalance, bearing wear or other potential problems. If the sensor detects that the vibration amplitude exceeds a preset threshold, the system will trigger corresponding warnings or protective measures, such as starting the liquid suspension bearing assembly 500 for suspension support to protect the main shaft and bearings from damage.

[0034] In one embodiment, the housing 100 includes a main housing 700 and a first housing 800 and a second housing 900 detachably connected to the main housing 700 . The first housing 800 is configured to seal and protect the first liquid suspension bearing 510 , and the second housing 900 is configured to seal and protect the second liquid suspension bearing 520 .

[0035] Specifically, the housing 100 is the main protective structure of the vertical liquid suspension electric spindle of the present application, which is used to accommodate and support the spindle 230, the liquid suspension bearing assembly 500 and other key components. The main housing 700 is the main part of the housing 100, and the main housing 700 provides the main structural support and protection. The first housing 800 is detachably connected to the main housing 700, and is used to seal and protect the first liquid suspension bearing 510. In this way, it is ensured that the lubricating oil in the first liquid suspension bearing 510 will not leak during the operation of the spindle 230, and external contaminants are prevented from entering. The second housing 900 is detachably connected to the main housing 700, and is used to seal and protect the second liquid suspension bearing 520. In this way, it is ensured that the lubricating oil in the second liquid suspension bearing 520 will not leak during the operation of the spindle 230, and external contaminants are prevented from entering. In addition, the three-layer structure design of the housing 100 facilitates the maintenance of the liquid suspension bearing and quick replacement when damaged.

[0036] In one embodiment, the outer side of the spindle 230 is also provided with a stepless adjustment slide rail, and the vibration detection sensor 400 is arranged on the stepless adjustment slide rail and has a slidable state and a locked state. The stepless adjustment slide rail is a special component arranged on the outer side of the spindle 230, which allows the vibration detection sensor 400 to slide on it and can be locked at any position. The locking can be a latch locking, a screw locking, etc. In this way, the vibration detection sensor 400 can adjust its position according to actual needs to more accurately monitor the vibration of the spindle. The vibration detection sensor 400 is installed on the stepless adjustment slide rail and can slide and lock on the slide rail to adapt to different monitoring needs. The vibration detection sensor 400 includes at least an acceleration sensor along a first direction and an acceleration sensor along a second direction, the first direction and the second direction are perpendicular to each other, and the first direction and the second direction are both perpendicular to the vertical direction. The vibration detection sensor 400 is used to monitor the vibration state of the vertical liquid suspension electric spindle in real time. It includes at least two acceleration sensors, which measure in the first direction and the second direction respectively. These two directions are perpendicular to each other and to the vertical direction. Figure 1 As shown, the Z axis is the vertical direction, and the X and Y axes are the acceleration sensor installation directions that are perpendicular to each other and perpendicular to the vertical direction. The acceleration sensor in the first direction is responsible for measuring the vibration acceleration along the X-axis direction, and the acceleration sensor in the second direction is responsible for measuring the vibration acceleration along the Y-axis direction. The acceleration sensor converts the measured vibration acceleration into an electrical signal output. After amplification, filtering and digital processing, the electrical signal is sent to the processor for analysis. The processor can monitor and evaluate the vibration signal in real time according to the preset algorithm and threshold. If the vibration amplitude exceeds the preset threshold, the system will trigger an alarm or take corresponding protective measures. For example, the liquid suspension bearing assembly 500 is started for suspension support to protect the main shaft and bearings from damage.

[0037] In one embodiment, if Figure 4As shown, the outer side surface of the main shaft 230 is provided with a preload bevel 2310, and the liquid suspension bearing assembly 500 is sleeved on the preload bevel 2310; specifically, the preload bevel 2310 includes a first preload bevel 2311 and a second preload bevel 2312, and the first preload bevel 2311 and the second preload bevel 2312 provide opposite preload forces to the liquid suspension bearing assembly 500. By adjusting the position of the liquid suspension bearing assembly 500 on the preload bevel 2310, adaptive adjustment of the preload force can be achieved. The first preload bevel 2311 and the second preload bevel 2312 provide preload forces in opposite directions to the liquid suspension bearing assembly 500, respectively. By adjusting the position of the bearing assembly on the two bevels, the preload forces can be balanced and the required tightening effect can be achieved, and it is determined that the liquid suspension bearing assembly 500 will not be displaced or even fall off due to the vibration of the main shaft 230, thereby ensuring the safety performance of the liquid suspension bearing assembly 500.

[0038] In other embodiments, in order to further enhance the safety performance of the liquid suspension bearing assembly 500, the main shaft 230 is designed as a hollow structure. In the hollow cavity of the main shaft, the embodiment of the present application is arranged with a coolant 240 for the precise position of the first liquid suspension bearing 510 and / or the second liquid suspension bearing 520. The coolant 240 can adopt an efficient flow-type circulating water cooling system, or a non-flowing special liquid cooling solution can be selected to quickly absorb and take away the heat generated by the liquid suspension bearing when the main shaft is running. This design ensures that the liquid suspension bearing assembly 500 can be cooled in time, thereby greatly improving its safety performance and operational stability.

[0039] In one embodiment, if Figure 5 As shown, the vertical liquid suspension electric spindle of the present application further includes a processor, which is configured to control the liquid suspension bearing assembly 500 according to the vibration monitoring data of the vibration detection sensor 400, and the processor executes the following control method steps: S100, obtaining vibration monitoring data sensed by the vibration detection sensor, wherein the vibration monitoring data includes vibration acceleration in a first direction and vibration acceleration in a second direction, wherein the first direction and the second direction are perpendicular to each other, and both the first direction and the second direction are perpendicular to a vertical direction; S200, in response to the vibration acceleration in the first direction having acceleration in positive and negative directions and the absolute value of the acceleration being greater than or equal to an acceleration threshold, and / or in response to the vibration acceleration in the second direction having acceleration in positive and negative directions and the absolute value of the acceleration being greater than or equal to the acceleration threshold, controlling the oil pump to operate so that the liquid suspension bearing assembly performs suspension support on the main shaft.

[0040] Specifically, vibration monitoring data is first obtained from the vibration detection sensor. These data include vibration acceleration in two key directions: the first direction and the second direction (such as Figure 1 X and Y axis directions in the middle). These two directions are perpendicular to each other and are perpendicular to the vertical direction, ensuring that the vibration of the main shaft in different directions can be fully monitored. The vibration detection sensor in the embodiment of the present application has high sensitivity and high precision, and can capture the vibration information of the main shaft in real time and accurately. The vibration acceleration data output by the sensor undergoes certain filtering and calibration processing to ensure the accuracy and reliability of the data. When the vibration acceleration in the first direction has acceleration changes in the positive and negative directions, and its absolute value is greater than or equal to the preset acceleration threshold, it indicates that the main shaft has significant vibration in the first direction. When the vibration acceleration in the second direction also has acceleration changes in the positive and negative directions, and its absolute value is also greater than or equal to the acceleration threshold, it indicates that the main shaft also has significant vibration in the second direction. As long as any of the above conditions (or both) are met, it can be considered that the vibration state of the main shaft exceeds the normal range and measures need to be taken to intervene. When the above conditions are met, the control system will issue an instruction to control the oil pump (not shown) to start working. The function of the oil pump is to provide the necessary hydraulic support for the liquid suspension bearing assembly so that it can effectively suspend and support the main shaft. By adjusting the output pressure and flow of the oil pump, the suspension force of the liquid suspension bearing assembly can be precisely controlled, thereby ensuring that the main shaft can maintain stable operation under vibration. One end of the oil pump is connected to the oil inlet hole, and the other end is connected to the oil outlet hole.

[0041] In another embodiment, if Figure 6 As shown, a pressure sensor 560 is further provided in the flexible oil film, and the processor is further configured to control the thickness of the oil cavity according to the pressure sensing data of the pressure sensor 560, and the processor further performs the following control method steps: S300, obtaining pressure monitoring data of the pressure sensor, wherein the pressure monitoring data includes a liquid pressure value in the flexible oil film; S400. When the liquid pressure value in the flexible oil film is greater than the pressure threshold range, the oil pump is controlled to reduce the oil injection speed to reduce the thickness of the oil chamber. When the liquid pressure value in the flexible oil film is less than the pressure threshold, the oil pump is controlled to increase the oil injection speed to increase the thickness of the oil chamber.

[0042] Specifically, in a vertical liquid suspension electric spindle system, the flexible oil film is a key part of the liquid suspension bearing assembly, which can form a stable liquid film between the spindle and the bearing to realize the suspension support of the spindle. In order to accurately control the thickness of this flexible oil film, thereby ensuring the stable suspension and operation of the spindle, a pressure sensor 560 is provided in the embodiment of the present application. The pressure sensor can monitor the liquid pressure value in the flexible oil film in real time and feed back these data to the processor. The processor first receives the pressure monitoring data from the pressure sensor 560. These data include the liquid pressure value at a certain key position in the flexible oil film, or the liquid pressure value at each key position in the flexible oil film, which can reflect the pressure distribution and change inside the oil film. When the liquid pressure value (or the average pressure value) in the flexible oil film exceeds the preset pressure threshold range (upper limit value), it indicates that the oil film is too thick or the pressure is too high, which may cause the spindle suspension to be unstable or the wear to be aggravated. At this time, it is necessary to reduce the thickness of the oil chamber to reduce the pressure. When the liquid pressure value in the flexible oil film is lower than the pressure threshold (lower limit), it indicates that the oil film is too thin or the pressure is insufficient, which may lead to direct contact or increased friction between the spindle and the bearing. At this time, the thickness of the oil chamber needs to be increased to increase the pressure.

[0043] Exemplarily, when the pressure is too high, the processor reduces the amount of liquid in the oil chamber by controlling the oil pump to reduce the oil injection speed, thereby reducing the thickness of the oil film and the pressure. For example, this is achieved by adjusting the speed or opening of the oil pump. When the pressure is too low, the processor increases the amount of liquid in the oil chamber by controlling the oil pump to increase the oil injection speed, thereby increasing the thickness of the oil film and the pressure. Similarly, this can also be achieved by adjusting the speed or opening of the oil pump. In this way, the thickness of the flexible oil film is accurately controlled and automatically dynamically adjusted according to the pressure monitoring data of the pressure sensor 560, thereby ensuring the stable suspension and efficient operation of the vertical liquid-suspended electric spindle.

[0044] Based on this, the embodiment of the present application provides a vertical liquid suspension electric spindle, in which rolling bearings and liquid suspension bearings are respectively arranged at both ends of the spindle. The spindle can be supported only by rolling bearings in the low-speed operation state. When the sensor detects that the vibration amplitude of the spindle exceeds the normal range, it means that the rolling bearing is worn or the processing accuracy cannot meet the current spindle operation speed requirement. At this time, the liquid suspension bearing is controlled to start working to perform liquid suspension support on the spindle. In this way, the support mode is flexibly switched according to the operating state of the spindle to ensure efficient and stable operation of the spindle. And during the process of liquid suspension support of the spindle, the oil inlet flow rate of the oil inlet hole of the liquid suspension bearing is less than or equal to the oil outlet flow rate of the oil outlet hole; in this way, through fine flow control, the heat generated during the operation of the spindle can be prevented from having an adverse effect on the oil chamber thickness of the liquid suspension bearing, which not only further improves the stability of the spindle operation, but also prolongs the service life of the liquid suspension bearing.

[0045] The present application also provides a computer program product, which includes one or more program codes stored in a computer-readable storage medium. The processor of the vertical liquid suspension electric spindle reads the program code from the computer-readable storage medium, and the processor executes the program code to complete the control method steps provided in the above embodiment.

[0046] A person skilled in the art will appreciate that all or part of the steps for implementing the above embodiments may be accomplished by hardware or by hardware associated with a program code, and the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a disk or an optical disk, etc.

[0047] It should be noted that the device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0048] Through the description of the above embodiments, it can be clearly understood by those skilled in the art that each embodiment can be implemented by means of software plus a general hardware platform, or by hardware. It can be understood by those skilled in the art that all or part of the processes in the above embodiment methods can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium, and when the program is executed, it can include the processes of the embodiments of the above methods. Among them, the storage medium can be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc.

[0049] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A vertical liquid suspended electric spindle, characterized in that: include: A casing (100), wherein the casing (100) is provided with an oil inlet hole (110) and an oil outlet hole (120); A drive assembly (200) disposed in the housing (100), the drive assembly (200) comprising a stator coil frame (210), a stator coil (220) disposed on the stator coil frame (210), and a main shaft (230) disposed in the stator coil frame (210); A rolling bearing assembly (300), the rolling bearing assembly (300) comprising a first rolling bearing (310) and a second rolling bearing (320) arranged at opposite ends of the main shaft (230), the rolling bearing assembly (300) being configured to support the main shaft (230); A vibration detection sensor (400), arranged on a side close to an output end of the main shaft (230), configured to monitor a vibration state of the main shaft (230); A liquid suspension bearing assembly (500), the liquid suspension bearing assembly (500) comprising a first liquid suspension bearing (510) and a second liquid suspension bearing (520) arranged at opposite ends of the main shaft (230), the first liquid suspension bearing (510) being arranged on the outside of the first rolling bearing (310), and the second liquid suspension bearing (520) being arranged on the outside of the second rolling bearing (320), the liquid suspension bearing assembly (500) being configured to suspend and support the main shaft (300) when the vibration detection sensor (400) detects that the vibration amplitude of the main shaft (230) exceeds a preset vibration amplitude; The first liquid suspension bearing (510) and / or the second liquid suspension bearing (520) comprises a flexible oil film (530) and a wear-resistant buffer layer (540) provided on an inner layer of the flexible oil film (530); one end of the flexible oil film (530) is connected to the oil inlet hole (110), and the other end is connected to the oil outlet hole (120); when the liquid suspension bearing assembly (500) is in a state of suspending and supporting the main shaft (300), the oil inlet flow rate of the oil inlet hole (110) is less than or equal to the oil outlet flow rate of the oil outlet hole (120).

2. The vertical liquid suspended electric spindle according to claim 1, characterized in that: The housing (100) is also provided with a pressure relief hole (130), and the first liquid suspension bearing (510) and / or the second liquid suspension bearing (520) further comprises a pressure valve (550) disposed in the flexible oil film (530), the pressure valve (550) being in communication with the pressure relief hole (130).

3. The vertical liquid suspended electric spindle according to claim 1, characterized in that: The first rolling bearing (310) is arranged on a side close to the output end of the main shaft (230), the first rolling bearing (310) comprises a first inner rolling bearing (3110) and a first outer rolling bearing (3120) which are arranged at intervals along the length direction of the main shaft (230), and the distance between the vibration detection sensor (400) and the first inner rolling bearing (3110) is greater than or equal to twice the distance between the first inner rolling bearing (3110) and the first outer rolling bearing (3120).

4. The vertical liquid suspended electric spindle according to claim 1, characterized in that: The housing (100) comprises a main housing (700) and a first housing (800) and a second housing (900) detachably connected to the main housing (700); the first housing (800) is configured to seal and protect the first liquid suspension bearing (510); and the second housing (900) is configured to seal and protect the second liquid suspension bearing (520).

5. The vertical liquid suspended electric spindle according to claim 1, characterized in that: The vibration detection sensor (400) comprises at least an acceleration sensor along a first direction and an acceleration sensor along a second direction, the first direction and the second direction are perpendicular to each other, and both the first direction and the second direction are perpendicular to the vertical direction; and / or, The outer side surface of the main shaft (230) is also provided with a steplessly adjustable slide rail, and the vibration detection sensor (400) is arranged on the steplessly adjustable slide rail and has a slidable state and a locked state.

6. The vertical liquid suspended electric spindle according to claim 1, characterized in that: The outer side surface of the main shaft (230) is provided with a pre-tightening inclined surface (2310), and the liquid suspension bearing assembly (500) is sleeved on the pre-tightening inclined surface (2310); and / or, The main shaft (230) is a hollow structure, and a cooling liquid (240) is provided in the hollow cavity of the main shaft (230) at corresponding positions of the first liquid suspension bearing (510) and / or the second liquid suspension bearing (520).

7. The vertical liquid suspended electric spindle according to claim 6, characterized in that: The pre-tightening inclined surface (2310) comprises a first pre-tightening inclined surface (2311) and a second pre-tightening inclined surface (2312), and the first pre-tightening inclined surface (2311) and the second pre-tightening inclined surface (2312) provide opposite pre-tightening forces to the liquid suspension bearing assembly (500).

8. The vertical liquid suspended electric spindle according to any one of claims 1 to 7, characterized in that: It also includes a processor, the processor being configured to control the liquid suspension bearing assembly (500) according to the vibration monitoring data of the vibration detection sensor (400), the processor executing the following control method steps: Acquire vibration monitoring data sensed by the vibration detection sensor, wherein the vibration monitoring data includes vibration acceleration in a first direction and vibration acceleration in a second direction, wherein the first direction and the second direction are perpendicular to each other, and both the first direction and the second direction are perpendicular to a vertical direction; In response to the vibration acceleration in the first direction having acceleration in positive and negative directions and the absolute value of the acceleration being greater than or equal to an acceleration threshold, and / or in response to the vibration acceleration in the second direction having acceleration in positive and negative directions and the absolute value of the acceleration being greater than or equal to the acceleration threshold, the oil pump is controlled to operate so that the liquid suspension bearing assembly performs suspension support on the main shaft.

9. The vertical liquid suspended electric spindle according to claim 8, characterized in that: A pressure sensor (560) is also provided in the flexible oil film, and the processor is further configured to control the thickness of the oil cavity according to pressure sensing data of the pressure sensor (560). The processor also executes the following control method steps: Acquiring pressure monitoring data of the pressure sensor, wherein the pressure monitoring data includes a liquid pressure value in the flexible oil film; When the liquid pressure value in the flexible oil film is greater than the pressure threshold range, the oil pump is controlled to reduce the oil injection speed to reduce the thickness of the oil chamber. When the liquid pressure value in the flexible oil film is less than the pressure threshold, the oil pump is controlled to increase the oil injection speed to increase the thickness of the oil chamber.

10. The vertical liquid suspended electric spindle according to claim 9, characterized in that: The main shaft (230) is provided with a temperature sensor, and the processor is further configured to control the oil inlet and oil outlet according to the temperature value sensed by the temperature sensor, and the processor further performs the following control method steps: Acquiring sensing data of the temperature sensor to obtain a measured temperature value of the spindle; The measured temperature value of the spindle is input into the oil quantity adjustment model to obtain the difference between the oil inlet and the oil outlet. The oil quantity adjustment model satisfies the following expression: Q in =Q out -1.028 (T-25) (T ≥ 25 °C), where Q in is the oil flow rate of the oil inlet hole, Q out is the oil flow rate of the oil outlet, and T is the measured temperature value during the operation of the spindle.

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