A vertical liquid suspension motorized spindle

Abstract

The embodiment of the application relates to the technical field of machine tool main shafts, and discloses a vertical liquid suspension electric main shaft, both ends of the main shaft are respectively provided with rolling bearings and liquid suspension bearings, the main shaft can be supported and operated only through the rolling bearings in a low-speed operation state, when a sensor detects that the vibration amplitude of the main shaft exceeds a normal range, it is indicated that the rolling bearings are worn or machining precision cannot meet the operation speed requirement of the current main shaft, at this time, the liquid suspension bearings are controlled to start working to liquid-suspensionally support the main shaft, in this way, the support mode is flexibly switched according to the operation state of the main shaft, so that the efficient and stable operation of the main shaft is ensured. Moreover, in the process that the main shaft is liquid-suspensionally supported, the oil inlet flow of the oil inlet hole of the liquid suspension bearing is less than or equal to the oil outlet flow of the oil outlet hole; the stability of the operation of the main shaft is further improved, and the service life of the liquid suspension bearing is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of machine tool spindles, in particular to a vertical liquid suspension electric spindle. BACKGROUND

[0002] Traditional machine tool electric spindles are usually supported by rolling bearings, and rolling bearings have been widely used in mechanical equipment. However, due to the sliding friction between the rolling elements and the cage, the contact between the rolling elements and the inner and outer raceways is often non-pure rolling, which can cause heating, wear, vibration and other problems, limiting the further improvement of the movement speed to ultra-high speed. At the same time, the rolling elements and the inner and outer raceways are in point and line rigid contact, which can cause excessive local stress and internal and external vibration transmission, making it difficult for manufacturing equipment using rolling bearings to break through the limit of micron / sub-micron machining precision. In addition, rolling bearings have the problem of wear and tear, which needs to be replaced regularly, which not only increases the maintenance cost, but also may affect the continuous operation and machining precision of the machine tool. SUMMARY

[0003] The main purpose of the present application is to provide a vertical liquid suspension electric spindle, which aims to solve the technical problems of the rolling bearings of the machine tool electric spindle in the prior art, which cannot meet the high-speed operation of the spindle and has high maintenance cost.

[0004] To achieve the above-mentioned purpose, a vertical liquid suspension electric spindle is provided in the embodiments of the present application, which comprises:

[0005] A machine shell is provided with an oil inlet hole and an oil outlet hole;

[0006] A driving assembly is arranged in the machine shell, which comprises a stator coil holder, a stator coil arranged on the stator coil holder, and a spindle arranged in the stator coil holder;

[0007] A rolling bearing assembly is arranged at the opposite ends of the spindle, which is configured to support the spindle;

[0008] A vibration detection sensor is arranged on one side close to the output end of the spindle, which is configured to monitor the vibration state of the spindle;

[0009] A liquid suspension bearing assembly is arranged at the opposite ends of the spindle, which comprises a first liquid suspension bearing arranged outside the first rolling bearing and a second liquid suspension bearing arranged outside the second rolling bearing, and the liquid suspension bearing assembly is configured to support the spindle when the vibration amplitude of the spindle monitored by the vibration detection sensor exceeds the preset vibration amplitude;

[0010] The first liquid suspension bearing and / or the second liquid suspension bearing comprise a flexible oil film and a wear-resistant buffer layer arranged in an inner layer of the flexible oil film, one end of the flexible oil film is communicated with the oil inlet hole, and the other end is communicated with the oil outlet hole; in a state of suspending and supporting the main shaft by the liquid suspension bearing assembly, the oil inlet flow of the oil inlet hole is less than or equal to the oil outlet flow of the oil outlet hole.

[0011] In a possible implementation, the shell is further provided with a pressure relief hole, and the first liquid suspension bearing and / or the second liquid suspension bearing further comprise a pressure valve arranged in the flexible oil film, and the pressure valve is communicated with the pressure relief hole.

[0012] In a possible implementation, the first rolling bearing is arranged on a side close to the output end of the main shaft, the first rolling bearing comprises 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.

[0013] In a possible implementation, the shell comprises a main shell and a first outer shell and a second outer shell detachably connected to the main shell, the first outer shell is configured to seal and protect the first liquid suspension bearing, and the second outer shell is configured to seal and protect the second liquid suspension bearing.

[0014] In a possible implementation, the vibration detection sensor comprises 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,

[0015] The outer side surface of the main shaft is further provided with a stepless adjustment slide rail, the vibration detection sensor is arranged on the stepless adjustment slide rail and has a slidable state and a locked state.

[0016] In a possible implementation, the outer side surface of the main shaft is provided with a pre-tightening inclined surface, and the liquid suspension bearing assembly is sleeved on the pre-tightening inclined surface; and / or,

[0017] The main shaft is a hollow structure, and the hollow cavity of the main shaft is provided with cooling liquid at corresponding positions of the first liquid suspension bearing and / or the second liquid suspension bearing.

[0018] In a possible implementation, the pre-tightening inclined surface comprises a first pre-tightening inclined surface and a second pre-tightening inclined surface, and the pre-tightening forces provided by the first pre-tightening inclined surface and the second pre-tightening inclined surface are opposite.

[0019] In a possible implementation, the system further comprises a processor configured to control the liquid suspension bearing assembly according to vibration monitoring data of the vibration detection sensor, the processor performing the following control method steps:

[0020] obtaining vibration monitoring data sensed by the vibration detection sensor, the vibration monitoring data comprising 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 perpendicular to a vertical direction;

[0021] in response to the vibration acceleration in the first direction having positive and negative directions and an absolute value greater than or equal to an acceleration threshold, and / or in response to the vibration acceleration in the second direction having positive and negative directions and an absolute value greater than or equal to the acceleration threshold, controlling the oil pump to operate so that the liquid suspension bearing assembly suspends and supports the main shaft.

[0022] In a possible implementation, the flexible oil film further comprises a pressure sensor, and the processor is further configured to control the thickness of the oil cavity according to pressure sensing data of the pressure sensor, the processor further performing the following control method steps:

[0023] obtaining pressure monitoring data of the pressure sensor, the pressure monitoring data comprising a liquid pressure value in the flexible oil film;

[0024] in a case where the liquid pressure value in the flexible oil film is greater than a pressure threshold range, controlling the oil pump to reduce the oil injection speed to reduce the thickness of the oil cavity, and in a case where the liquid pressure value in the flexible oil film is less than the pressure threshold, controlling the oil pump to increase the oil injection speed to increase the thickness of the oil cavity.

[0025] In a possible implementation, the main shaft comprises a temperature sensor, and the processor is further configured to control the oil injection amount and the oil discharge amount according to a sensed temperature value of the temperature sensor, the processor further performing the following control method steps:

[0026] obtaining a measured temperature value of the main shaft from sensing data of the temperature sensor;

[0027] inputting the measured temperature value of the main shaft into an oil amount adjustment model to obtain a difference between the oil injection amount and the oil discharge amount, the oil amount adjustment model satisfying the following expression:

[0028] Q in =Q out -1.028(T-25)(T≥25℃), wherein Q in is the oil injection flow rate of the oil injection hole, Q out is the oil discharge flow rate of the oil discharge hole, and T is the measured temperature value during operation of the main shaft.

[0029] Different from the prior art, the vertical liquid suspension motorized spindle provided by the embodiment of the application is provided with a rolling bearing and a liquid suspension bearing at two ends of the spindle, the spindle can be supported for operation only by the rolling bearing in a low-speed operation state, when the vibration amplitude of the spindle detected by the sensor exceeds the normal range, it indicates that the rolling bearing is worn or the machining precision cannot meet the operation speed requirement of the current spindle, 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, so as to ensure the efficient and stable operation of the spindle. Moreover, during the liquid suspension support of the spindle, the oil inlet flow of the oil inlet hole of the liquid suspension bearing is less than or equal to the oil outlet flow 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 adversely affecting the oil cavity thickness of the liquid suspension bearing, not only the stability of the operation of the spindle is further improved, but also the service life of the liquid suspension bearing is prolonged. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only show some embodiments of the application, and for those skilled in the art, other drawings can also be obtained from the drawings shown without any creative effort.

[0031] Figure 1 A sectional view of the vertical liquid suspension motorized spindle in some embodiments of the application;

[0032] Figure 2 A three-dimensional structure schematic diagram of the vertical liquid suspension motorized spindle in some embodiments of the application;

[0033] Figure 3 A liquid suspension bearing structure schematic diagram of the vertical liquid suspension motorized spindle in some embodiments of the application;

[0034] Figure 4 A spindle structure schematic diagram of the vertical liquid suspension motorized spindle in some embodiments of the application;

[0035] Figure 5 A processor control method flowchart schematic diagram of the vertical liquid suspension motorized spindle in some embodiments of the application;

[0036] Figure 6 A processor control method flowchart schematic diagram of the vertical liquid suspension motorized spindle in some embodiments of the application.

[0037] The implementation, functional features and advantages of the application will be further described with reference to the embodiments and the drawings. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0039] It should be noted that all directionality indications (such as up, down, left, right, front, back, and the like) in the embodiments of the present application are only used to explain the relative positional relationship, movement condition and the like between components in a certain specific posture (as shown in the drawings), and if the specific posture changes, the directionality indications will also change accordingly.

[0040] In addition, the descriptions of "first", "second" and the like in the present application are only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include at least one of the features. In addition, "and / or" throughout the text includes three solutions, for example, A and / or B includes A technical solution, B technical solution, and A and B simultaneously meet the technical solution; in addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of a person of ordinary skill in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, nor is it within the scope of protection claimed by the present application.

[0041] 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 elements and the cage, the contact between the rolling elements and the inner and outer raceways is often non-pure rolling, which can cause heating, wear, vibration and other problems, limiting the further improvement of the movement speed to ultra-high speed. At the same time, the rolling elements and the inner and outer raceways are in point and line rigid contact, which can cause excessive local stress and internal and external vibration transmission, making it difficult for manufacturing equipment using rolling bearings to break through the limit of micron / sub-micron machining precision. In addition, rolling bearings have the problem of wear and tear, which needs to be replaced regularly, which not only increases the maintenance cost, but also may affect the continuous operation and machining precision of the machine tool.

[0042] In view of the above problems, as shown in Figures 1-4 The vertical liquid suspension electric spindle provided by the present application comprises:

[0043] A machine shell 100, wherein an oil inlet hole 110 and an oil outlet hole 120 are formed in the machine shell 100;

[0044] A driving assembly 200 is arranged in the casing 100, and the driving assembly 200 comprises a stator coil bracket 210, a stator coil 220 arranged on the stator coil bracket 210, and a main shaft 230 arranged in the stator coil bracket 210.

[0045] A rolling bearing assembly 300 is arranged at opposite ends of the main shaft 230, and the rolling bearing assembly 300 is configured to support the main shaft 230.

[0046] A vibration detection sensor 400 is arranged on a side close to an output end of the main shaft 230, and the vibration detection sensor 400 is configured to monitor a vibration state of the main shaft 230.

[0047] A liquid suspension bearing assembly 500 is arranged at opposite ends of the main shaft 230, and the liquid suspension bearing assembly 500 comprises a first liquid suspension bearing 510 and a second liquid suspension bearing 520. The first liquid suspension bearing 510 is arranged outside the first rolling bearing 310, and the second liquid suspension bearing 520 is arranged outside the second rolling bearing 320. The liquid suspension bearing assembly 500 is configured to suspend and support the main shaft 300 when the vibration detection sensor 400 detects that a vibration amplitude of the main shaft 230 exceeds a preset vibration amplitude.

[0048] The first liquid suspension bearing 510 and / or the second liquid suspension bearing 520 comprise a flexible oil film 530 and a wear-resistant buffer layer 540 arranged on an inner layer of the flexible oil film 530. One end of the flexible oil film 530 is in communication with the oil inlet hole 110, and the other end is in communication with the oil outlet hole 120. In the state of suspending and supporting the main shaft 300, an oil inlet flow rate of the oil inlet hole 110 is less than or equal to an oil outlet flow rate of the oil outlet hole 120.

[0049] Specifically, the casing 100 serves as the external protective shell of the entire motorized spindle, and the casing 100 is designed with an oil inlet hole 110 and an oil outlet hole 120, which are respectively used to provide lubricating oil to the liquid suspension bearing assembly 500 and discharge used lubricating oil, so as to ensure that the liquid suspension bearing assembly 500 maintains a stable filling state to stably support the spindle 230; the drive assembly 200 is located inside the casing 100 and includes a stator coil holder 210, a stator coil 220, and a spindle 230. The stator coil 220 is wound around the stator coil holder 210 and generates a magnetic field through energization to drive the spindle 230 to rotate in the stator coil holder 210. The rolling bearing assembly 300 includes a first rolling bearing 310 and a second rolling bearing 320, which are respectively mounted at opposite ends of the spindle 230 and serve to support the spindle 230 to ensure that the spindle 230 remains stable during rotation. The vibration detection sensor 400 is mounted close to the output end of the spindle 230 and is used to monitor the vibration state of the spindle 230 in real time. When the vibration amplitude exceeds a preset value, the sensor sends 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 outside the first rolling bearing 310 and the second rolling bearing 320. When the vibration detection sensor 400 detects abnormal vibration of the spindle 230, the liquid suspension bearing assembly 500 starts to work and suspends and supports the spindle 230.

[0050] When the spindle 230 rotates normally, the rolling bearing assembly 300 mainly provides support. 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 circulating lubricating oil (the circulating amount of lubricating oil is less than that in the start state of the liquid suspension bearing assembly 500) to maintain the wetting and lubricating performance of the flexible oil film 530. When the vibration detection sensor 400 detects that the vibration amplitude of the spindle 230 exceeds a preset value, the system determines that the rolling bearing 310 / 320 may be worn or the running speed of the spindle 230 exceeds the precision range of the rolling bearing. At this time, the system sends a command to start the liquid suspension bearing assembly 500. After receiving the start command, the liquid suspension bearing assembly 500 starts 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 spindle 230 and the bearing seat (provided outside the flexible oil film 530) to provide suspension support. At the same time, the used lubricating oil is discharged through the oil outlet hole 120 to maintain the cleanliness and temperature stability of the oil film. The wear-resistant buffer layer 540 is made of wear-resistant rubber material and has stable wear-resistant performance.

[0051] In the liquid suspension support state, the system precisely controls the oil inlet flow rate of the oil inlet hole 110 and the oil outlet flow rate of the oil outlet hole 120, and ensures 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.

[0052] In order to reduce the adverse effects of temperature on the oil film thickness and thereby maintain the stability and reliability of the suspension support, in an embodiment, the oil inlet flow rate and the oil outlet flow rate can be controlled according to the temperature. The embodiment introduces a temperature-based adjustment model to adjust the balance of the oil inlet flow rate and the oil outlet flow rate.

[0053] The embodiment trains and calibrates the parameters of the adjustment model by collecting a large amount of data to obtain the following model expression: Q in =Q out -1.028 (T-25), the units of the oil inlet flow rate and the oil outlet flow rate are liters per second, where Q in represents the oil inlet flow rate of the oil inlet hole 110, Q out represents the oil outlet flow rate of the oil outlet hole 120, and T represents the measured temperature during the operation of the main shaft 230, and 25 represents the reference temperature (at a temperature of 25°C, the oil inlet flow rate and the oil outlet flow rate reach a preset balance state). When the temperature of the main shaft rises (greater than 25°C), the temperature at the support of the flexible oil film 530 also rises, at which time the flexible oil film 530 expands due to heat. Therefore, 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. In the case where one of the oil inlet flow rate or the oil outlet flow rate is known, the other flow rate value can be calculated according to the model formula.

[0054] Based on this, the vertical liquid suspension electric main shaft provided by the embodiment can automatically switch to the liquid suspension support mode when the main shaft vibrates abnormally, ensuring the stable operation of the main shaft, and improving the reliability and service life of the equipment.

[0055] In an embodiment, 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 arranged in the flexible oil film 530, and the pressure valve 550 is in communication with the pressure relief hole 130.

[0056] Specifically, the pressure relief hole 130 is an additional hole on the housing 100, which allows excess lubricating oil or gas to be discharged to prevent damage to the liquid suspension bearing or the spindle when the pressure inside the liquid suspension bearing assembly 500 is too high. The pressure valve 550 is a component disposed inside the first liquid suspension bearing 510 and / or the second liquid suspension bearing 520, specifically inside the flexible oil film 530. The pressure valve 550 functions to automatically open when the pressure inside the oil film reaches a preset threshold, allowing lubricating oil or gas to be discharged through the pressure relief hole 130, thereby maintaining the stability of the pressure inside the oil film.

[0057] When the spindle 230 rotates normally under the support of the liquid suspension bearing assembly 500, the flexible oil film 530 forms a stable lubricating support layer between the spindle 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 spindle. When the pressure inside the oil film exceeds the preset safety threshold, the pressure valve 550 is automatically triggered to open, and excess lubricating oil or gas will be discharged outside the housing 100 through the pressure valve 550 and the pressure relief hole 130. The pressure relief process will continue until the pressure inside the oil film drops to a safe range, at which point 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 spindle 230.

[0058] In an embodiment, the first rolling bearing 310 is disposed near the output end of the spindle 230, and the first rolling bearing 310 includes a first inner rolling bearing 3110 and a first outer rolling bearing 3120 disposed along the length of the spindle 230. 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.

[0059] Specifically, the first rolling bearing 310 includes two independent bearings, namely a first inner rolling bearing 3110 and a first outer rolling bearing 3120, which are arranged at intervals along the length of the main shaft 230. This design can provide better support effect and disperse the load on the main shaft. The vibration detection sensor 400 is installed at a distance from the first inner rolling bearing 3110 in the present embodiment. 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, thereby more comprehensively evaluating the running state of the main shaft. When the main shaft 230 starts to rotate, the vibration detection sensor 400 will monitor the vibration state of the main shaft in real time. Since the sensor is installed at a distance from the first inner rolling bearing 3110, it can capture vibration signals in a wider frequency range, including vibrations that may be caused by main shaft imbalance, bearing wear or other potential problems. If the sensor detects that the vibration amplitude exceeds the preset threshold, the system will trigger corresponding warning or protection measures, such as starting the liquid suspension bearing assembly 500 for suspension support, to protect the main shaft and bearings from damage.

[0060] In an embodiment, the machine housing 100 includes a main housing 700, and a first outer shell 800 and a second outer shell 900 detachably connected to the main housing 700, the first outer shell 800 being configured to seal and protect the first liquid suspension bearing 510, and the second outer shell 900 being configured to seal and protect the second liquid suspension bearing 520.

[0061] Specifically, the machine housing 100 is the main protection structure of the vertical liquid suspension motorized spindle of the present application, used to accommodate and support the main shaft 230, the liquid suspension bearing assembly 500 and other key components. The main housing 700 serves as the main part of the machine housing 100, and provides the main structural support and protection. The first outer shell 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 does not leak during the operation of the main shaft 230, and at the same time, external contaminants are prevented from entering. The second outer shell 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 also does not leak during the operation of the main shaft 230, and at the same time, external contaminants are prevented from entering. Furthermore, the three-layer structure design of the machine housing 100 facilitates the maintenance of the liquid suspension bearing and the quick replacement in case of damage.

[0062] In an embodiment, the outer side of the main shaft 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 main shaft 230, which allows the vibration detection sensor 400 to slide thereon 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 condition of the main shaft. 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 motorized spindle in real time. It includes at least two acceleration sensors, which measure along the first direction and the second direction respectively. The two directions are perpendicular to each other and both perpendicular to the vertical direction. As shown in Figure 1 the first direction of the acceleration sensor is responsible for measuring the vibration acceleration along the X-axis direction, and the second direction of the acceleration sensor 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 digitization 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 value. If the vibration amplitude exceeds the preset threshold value, the system will trigger an alarm or take corresponding protection measures. For example, the liquid suspension bearing assembly 500 is started to be suspended and supported to protect the main shaft and the bearing from damage.

[0063] In an embodiment, as Figure 4As shown, the outer side of the main shaft 230 is provided with a pre-tightening slope 2310, and the liquid suspension bearing assembly 500 is sleeved on the pre-tightening slope 2310. Specifically, the pre-tightening slope 2310 includes a first pre-tightening slope 2311 and a second pre-tightening slope 2312, and the first pre-tightening slope 2311 and the second pre-tightening slope 2312 provide opposite pre-tightening forces to the liquid suspension bearing assembly 500. By adjusting the position of the liquid suspension bearing assembly 500 on the pre-tightening slope 2310, the pre-tightening force can be adaptively adjusted. The first pre-tightening slope 2311 and the second pre-tightening slope 2312 provide opposite pre-tightening forces to the liquid suspension bearing assembly 500, and by adjusting the position of the bearing assembly on the two slopes, the pre-tightening forces can be balanced to achieve the desired tightening effect, so that the liquid suspension bearing assembly 500 will not be displaced or even fall off due to vibration of the main shaft 230, and the safety performance of the liquid suspension bearing assembly 500 is ensured.

[0064] 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, a cooling liquid 240 is arranged according to the accurate position of the first liquid suspension bearing 510 and / or the second liquid suspension bearing 520. The cooling liquid 240 can adopt a high-efficiency flow type circulating water cooling system, or a non-flow type special liquid cooling scheme, to quickly absorb and remove the heat generated by the liquid suspension bearing during operation of the main shaft. This design ensures that the liquid suspension bearing assembly 500 can be cooled in time, thereby greatly improving its safety performance and operation stability.

[0065] In an embodiment, as shown in Figure 5 The vertical liquid suspension motorized spindle of the present application further includes a processor configured to control the liquid suspension bearing assembly 500 according to vibration monitoring data of the vibration detection sensor 400. The processor performs the following control method steps:

[0066] S100, obtaining vibration monitoring data sensed by the vibration detection sensor, the vibration monitoring data including 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 the vertical direction;

[0067] S200, in response to the vibration acceleration in the first direction having positive and negative directions of acceleration and the absolute value of the acceleration being greater than or equal to an acceleration threshold value, and / or in response to the vibration acceleration in the second direction having positive and negative directions of acceleration and the absolute value of the acceleration being greater than or equal to an acceleration threshold value, controlling the oil pump to work so that the liquid suspension bearing assembly suspends and supports the main shaft.

[0068] Specifically, first, vibration monitoring data is acquired from the vibration detection sensor. These data include vibration acceleration in two key directions: the first direction and the second direction (as shown in Figure 1 The two directions are perpendicular to each other and both are perpendicular to the vertical direction, ensuring that the vibration of the main shaft in different directions can be comprehensively monitored. The vibration detection sensor in the embodiment 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 is subjected to certain filtering and calibration processing to ensure the accuracy and reliability of the data. When the vibration acceleration in the first direction has positive and negative acceleration changes, and its absolute value is greater than or equal to a preset acceleration threshold, it indicates that there is significant vibration of the main shaft in the first direction. When the vibration acceleration in the second direction also has positive and negative acceleration changes, and its absolute value is also greater than or equal to the acceleration threshold, it indicates that there is also significant vibration of the main shaft in the second direction. As long as any of the above conditions is met (or both are met), it is considered that the vibration state of the main shaft is out of the normal range, and measures need to be taken for intervention. In the case where 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, precise control of the suspension force of the liquid suspension bearing assembly can be achieved, thereby ensuring that the main shaft can still run stably in the vibration state. One end of the oil pump is in communication with the oil inlet hole, and the other end is in communication with the oil outlet hole.

[0069] In another embodiment, as shown in Figure 6 a pressure sensor 560 is further arranged 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. The processor further performs the following control method steps:

[0070] S300, acquiring pressure monitoring data of the pressure sensor, the pressure monitoring data including a liquid pressure value in the flexible oil film;

[0071] S400, in the case where the liquid pressure value in the flexible oil film is greater than a pressure threshold range, controlling the oil pump to reduce the oil injection speed to reduce the oil cavity thickness, and in the case where the liquid pressure value in the flexible oil film is less than the pressure threshold, controlling the oil pump to increase the oil injection speed to increase the oil cavity thickness.

[0072] Specifically, in the 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 achieve the suspension support of the spindle. In order to accurately control the thickness of the flexible oil film, thereby ensuring the stable suspension and operation of the spindle, the pressure sensor 560 is provided in the embodiment. The pressure sensor can monitor the liquid pressure value in the flexible oil film in real time and feed back the data to the processor. The processor first receives the pressure monitoring data from the pressure sensor 560. The data includes the liquid pressure value at a key position in the flexible oil film or the liquid pressure values at multiple key positions in the flexible oil film, which can reflect the pressure distribution and change in the oil film. When the liquid pressure value (or 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 unstable suspension or accelerated wear of the spindle. At this time, the oil cavity thickness needs to be reduced to reduce the pressure. When the liquid pressure value in the flexible oil film is lower than the pressure threshold (lower limit value), it indicates that the oil film is too thin or the pressure is insufficient, which may cause direct contact or increased friction between the spindle and the bearing. At this time, the oil cavity thickness needs to be increased to increase the pressure.

[0073] For example, in the case of excessive pressure, the processor reduces the liquid amount in the oil cavity by controlling the oil pump to reduce the oil injection speed, thereby reducing the oil film thickness and pressure. For example, by adjusting the speed or opening of the oil pump. In the case of low pressure, the processor increases the liquid amount in the oil cavity by controlling the oil pump to increase the oil injection speed, thereby increasing the oil film thickness and pressure. Similarly, it 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 adjusted according to the pressure monitoring data of the pressure sensor 560, thereby ensuring the stable suspension and efficient operation of the vertical liquid suspension electric spindle.

[0074] Based on this, the vertical liquid suspension electric spindle provided by the embodiment of the present application is provided with rolling bearings and liquid suspension bearings at both ends of the spindle. The spindle can be supported and operated only by the rolling bearings in the low-speed operation state. When the sensor detects that the vibration amplitude of the spindle exceeds the normal range, it indicates that the rolling bearings are worn or the machining precision cannot meet the current operation speed requirement of the spindle. 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. Moreover, during the liquid suspension support of the spindle, the oil inlet flow rate of the liquid suspension bearing oil inlet hole 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 adversely affecting the oil cavity 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.

[0075] The embodiment of the present application further provides a computer program product, which comprises one or more pieces of program code stored in a computer readable storage medium. A processor of the vertical liquid suspension motorized spindle reads the program code from the computer readable storage medium, and the processor executes the program code to complete the steps of the control method provided in the above embodiment.

[0076] Those skilled in the art can understand that all or part of the steps of the above-mentioned embodiments can be completed by hardware, or by program code related hardware, and the program can be stored in a computer readable storage medium. The storage medium mentioned above can be a read-only memory, a magnetic disk or an optical disk.

[0077] It should be noted that the above-described device embodiments are only schematic, and the units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, i.e. they can be located in one place, or distributed on multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the embodiment.

[0078] From the above description of the embodiments, those skilled in the art can clearly understand that the embodiments can be implemented by means of software plus a general hardware platform, and of course, can also be implemented by hardware. Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by a computer program instructing related hardware, and the program can be stored in a computer readable storage medium. When the program is executed, it can include the processes of the above-mentioned embodiment methods. The storage medium can be a magnetic disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc.

[0079] The above description is only the preferred embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structure transformation made according to the inventive concept of the present application, and direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A vertical liquid suspension motorized spindle characterized in that, The vertical liquid suspension motorized spindle comprises a shell (100) having an oil inlet hole (110) and an oil outlet hole (120) formed therein; a driving assembly (200) arranged in the shell (100), wherein the driving assembly (200) comprises a stator coil bracket (210), a stator coil (220) arranged on the stator coil bracket (210), and a main shaft (230) arranged in the stator coil bracket (210); a 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), wherein the rolling bearing assembly (300) is 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) and configured to monitor a vibration state of the main shaft (230); and a 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), wherein the first liquid suspension bearing (510) is arranged outside the first rolling bearing (310), the second liquid suspension bearing (520) is arranged outside the second rolling bearing (320), and the liquid suspension bearing assembly (500) is configured to suspend and support the main shaft (300) when the vibration detection sensor (400) detects that a 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) arranged on an inner layer of the flexible oil film (530), one end of the flexible oil film (530) is in communication with the oil inlet hole (110), and the other end is in communication with the oil outlet hole (120); when the liquid suspension bearing assembly (500) is in the state of suspending and supporting the main shaft (300), an oil inlet flow rate of the oil inlet hole (110) is less than or equal to an oil outlet flow rate of the oil outlet hole (120). The main shaft (230) is provided with a pre-tightening inclined surface (2310) on an outer side surface, the liquid suspension bearing assembly (500) is sleeved on the pre-tightening inclined surface (2310), 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). The vertical liquid suspension motorized spindle further comprises a processor, a temperature sensor is arranged on the main shaft (230), the processor is configured to control an oil inlet amount and an oil outlet amount according to a sensing temperature value of the temperature sensor, and the processor performs the following control method steps: obtaining a measured temperature value of the main shaft by acquiring sensing data of the temperature sensor. ​ ​ ​ ​ ​ The measured temperature value of the main shaft is input into an oil quantity adjustment model to obtain a difference between the oil inlet quantity and the oil outlet quantity, the oil quantity adjustment model satisfying the following expression: Q in =Q out -1.028(T-25), T≥25℃, wherein, Q in is the oil inlet flow of the oil inlet hole, Q out is the oil outlet flow of the oil outlet hole, and T is the measured temperature value during the operation of the main shaft.

2. The vertical liquid suspended motorized spindle of claim 1 wherein, The shell (100) is further 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) arranged in the flexible oil film (530), and the pressure valve (550) is in communication with the pressure relief hole (130).

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

4. The vertical liquid suspended motorized spindle of claim 1 wherein, The shell (100) comprises a main shell (700), and a first outer shell (800) and a second outer shell (900) detachably connected to the main shell (700), the first outer shell (800) is configured to seal and protect the first liquid suspension bearing (510), and the second outer shell (900) is configured to seal and protect the second liquid suspension bearing (520).

5. The vertical liquid suspended motorized spindle of claim 1 wherein, The vibration detection sensor (400) comprises 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, An outer side of the main shaft (230) is further provided with a stepless adjustment sliding rail, and the vibration detection sensor (400) is arranged on the stepless adjustment sliding rail and has a slidable state and a locked state.

6. The vertical liquid suspended motorized spindle of claim 1 wherein, The main shaft (230) is a hollow structure, and a cooling liquid (240) is arranged in a hollow cavity of the main shaft (230) at a corresponding position of the first liquid suspension bearing (510) and / or the second liquid suspension bearing (520).

7. A vertical liquid suspended motorized spindle as claimed in any of the claims 1-6, characterized in that, The processor is further configured to control the liquid suspension bearing assembly (500) according to vibration monitoring data of the vibration detection sensor (400), and the processor performs the following control method steps: Obtaining vibration monitoring data sensed by the vibration detection sensor, the vibration monitoring data comprising 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 the first direction and the second direction are both perpendicular to the vertical direction; In response to the vibration acceleration in the first direction having positive and negative directions of acceleration and the absolute value of the acceleration being greater than or equal to an acceleration threshold value, and / or in response to the vibration acceleration in the second direction having positive and negative directions of acceleration and the absolute value of the acceleration being greater than or equal to an acceleration threshold value, the oil pump is controlled to work so that the liquid suspension bearing assembly suspends and supports the main shaft.

8. The vertical liquid suspended motorized spindle of claim 7 wherein, The flexible oil film is further provided with a pressure sensor (560), and the processor is further configured to perform thickness control of the oil cavity according to pressure sensing data of the pressure sensor (560), and the processor further performs the following control method steps: acquiring pressure monitoring data of the pressure sensor, the pressure monitoring data including a liquid pressure value in the flexible oil film; in a case where the liquid pressure value in the flexible oil film is greater than a pressure threshold range, controlling the oil pump to reduce the oil injection speed to reduce the oil cavity thickness, and in a case where the liquid pressure value in the flexible oil film is less than the pressure threshold, controlling the oil pump to increase the oil injection speed to increase the oil cavity thickness.

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