Milling electric spindle with built-in integrated sensor

Abstract

The utility model provides a milling motorized spindle with a built-in integrated sensor, which comprises a rotor shaft, a front bearing pack, a spindle shell main body, a motor stator, a spindle shell front sleeve, an integrated rear end cover, multiple sensors, a cooling system and an exhaust system, and the multiple sensors comprise a temperature sensor, a vibration sensor and a thermal elongation sensor; the temperature sensor monitors the temperature of the motor stator and is installed in a radial hole of the main shaft shell body. The vibration sensor collects vibration signals of the front bearing set and is installed in an axial hole of the front sleeve of the main shaft shell. The thermal elongation sensor measures the axial displacement of the front end face of the rotor shaft and is installed on the outer end face of the front bearing set. And a multi-channel AD conversion module and a signal processing module are arranged in the integrated rear end cover. The temperature of a motor stator is monitored through multiple sensors, vibration signals of a front bearing pack are collected, axial displacement of the front end face of a rotor shaft is measured, a multi-physical-quantity synchronous collection network is constructed, and multi-parameter coupling analysis is conducted through a multi-channel AD conversion module and a signal processing module.

Description

Technical Field

[0001] This utility model relates to the field of electric spindle technology, and in particular to a milling electric spindle with a built-in integrated sensor. Background Technology

[0002] Electric spindles are a new technology in the field of CNC machine tools that integrates the machine tool spindle with the spindle motor. High-speed CNC machine tool main drive systems eliminate belt drives and gear drives, with the machine tool spindle directly driven by an internal electric motor, thus shortening the length of the main drive chain to zero and achieving "zero transmission" for the machine tool. Although mainstream electric spindles at home and abroad achieve micron-level runout control through high-precision bearings and dynamic balancing technology, they generally use external or separate sensors, resulting in data silos in traditional electric spindle systems. This makes it impossible to simultaneously acquire multi-dimensional parameters such as vibration, temperature, and thermal deformation, and lacks multi-parameter coupling analysis of temperature-vibration-load. During high-speed spindle operation, bearing temperature rises >15℃, causing thermal elongation fluctuations exceeding 2μm. Furthermore, traditional cooling systems have insufficient heat dissipation efficiency (temperature rise suppression rate <50%), resulting in excessive end runout / radial runout accuracy. Utility Model Content

[0003] This invention addresses the lack of multi-parameter coupling analysis of temperature, vibration, and load, as well as the insufficient heat dissipation efficiency of traditional cooling systems, by providing a milling electric spindle with a built-in integrated sensor that offers multi-dimensional signal synchronous capture and good heat dissipation efficiency.

[0004] This utility model provides the following technical solution: a milling electric spindle with built-in integrated sensors, including a rotor shaft, a front bearing assembly, a spindle housing body, a motor stator, a front sleeve of the spindle housing, an integrated rear end cover, multiple sensors, a cooling system, and an exhaust system. The multiple sensors include a temperature sensor, a vibration sensor, and a thermal expansion sensor. The temperature sensor is used to monitor the temperature of the motor stator and is installed in a radial hole in the spindle housing body. The vibration sensor is used to collect the vibration signal of the front bearing assembly and is installed in an axial hole in the front sleeve of the spindle housing. The thermal expansion sensor is used to measure the axial displacement of the front end face of the rotor shaft and is installed on the outer end face of the front bearing assembly. The integrated rear end cover has a built-in multi-channel AD conversion module and a signal processing module.

[0005] In some embodiments, the main body of the spindle housing is interference-fitted with the front sleeve of the spindle housing, with an interference of 0.02-0.03 mm; an encoder wheel and an encoder are installed at the rear end of the rotor shaft, with the encoder installed on the outside of the encoder wheel and a gap of 0.1±0.02 mm.

[0006] In some embodiments, the rear end of the spindle housing body is provided with an inlet for coolant to flow in, and the cooling system includes a spiral cooling channel. The spiral cooling channel is located inside the spindle housing body and has a lead angle of 30°. The gap between the inner wall of the spiral cooling channel and the motor stator is 0.5 mm. The coolant flows into the spiral cooling channel through the inlet.

[0007] In some embodiments, the cooling system includes an annular cooling sleeve and a cooling channel. The annular cooling sleeve is installed on the outside of the front bearing assembly, and the contact surface between the annular cooling sleeve and the outer ring of the front bearing assembly is provided with a microgroove structure with a depth of 0.2 mm and a spacing of 2 mm. The annular cooling sleeve is connected to the spiral cooling channel through the cooling channel.

[0008] In some embodiments, the exhaust system includes a plurality of vent holes that extend from front to back, and the plurality of vent holes are arranged at equal intervals around the central axis of the rotor shaft.

[0009] In some embodiments, the signal processing module is connected to the multi-channel AD conversion module via a PCIe interface. The multi-channel AD conversion module includes a temperature AD converter, a vibration signal AD converter, and a displacement signal AD converter. The temperature AD converter samples the temperature sensor, the vibration signal AD converter samples the vibration sensor, and the displacement signal AD converter samples the thermal elongation sensor.

[0010] Compared with the prior art, the advantages of this utility model are as follows: a temperature sensor is installed in the radial hole of the main body of the spindle housing; a vibration sensor is installed in the axial hole of the front sleeve of the spindle housing; and a thermal expansion sensor is installed on the outer end face of the front bearing assembly, thereby monitoring the stator temperature of the motor, collecting the vibration signal of the front bearing assembly, measuring the axial displacement of the front end face of the rotor shaft, constructing a multi-physical quantity synchronous acquisition network, and performing multi-parameter coupled analysis of temperature, vibration, and load through a multi-channel AD conversion module and a signal processing module.

[0011] Combined with the closed-loop heat dissipation channel formed by the spiral cooling channel and the annular cooling jacket, the temperature rise of the motor stator and bearing assembly is effectively controlled. The vent hole discharges the oil mist in the front bearing assembly area under a certain centrifugal force when the electric spindle rotates, which can better prevent oil mist from escaping. Attached Figure Description

[0012] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of the overall cross-sectional structure of the milling electric spindle of this utility model;

[0014] Figure 2 This is a schematic diagram of the connection structure between the main body of the spindle housing and the front sleeve of the spindle housing of this utility model.

[0015] Figure 3 This is a hardware architecture diagram of the signal processing module of this utility model;

[0016] Figure 4 This is a schematic diagram of the rotor shaft of this utility model.

[0017] In the diagram: 1. Rotor shaft; 2. Front bearing assembly; 3. Main spindle housing body; 301. Radial hole; 302. Annular cooling jacket; 303. Spiral cooling channel; 304. Inlet; 305. Vent hole; 4. Temperature sensor; 5. Front sleeve of main spindle housing; 501. Axial hole; 6. Rear sleeve of main spindle housing; 7. Motor stator; 8. Integrated rear end cover; 9. Rear bearing assembly; 10. Encoder wheel; 11. Encoder; 12. Vibration sensor; 13. Thermal expansion sensor; 14. Cooling channel. Detailed Implementation

[0018] The present application will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0019] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0021] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. The illustrations only show the components related to this application and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0022] Additionally, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that practice can be carried out without these specific details.

[0023] The technical solutions provided by the various embodiments of this application are described below with reference to the accompanying drawings.

[0024] Please see Figure 1-4 As shown in this embodiment: a milling electric spindle with built-in integrated sensors includes a rotor shaft 1, a front bearing assembly 2, a spindle housing body 3, a motor stator 7, a front sleeve of the spindle housing 5, an integrated rear end cover 8, multiple sensors, a cooling system, and an exhaust system. The multiple sensors include a temperature sensor 4, a vibration sensor 12, and a thermal expansion sensor 13. The temperature sensor 4 is used to monitor the temperature of the motor stator 7 and is installed in the radial hole 301 of the spindle housing body 3. The vibration sensor 12 is used to collect the vibration signal of the front bearing assembly 2 and is installed in the axial hole 501 of the front sleeve of the spindle housing 5. The thermal expansion sensor 13 is used to measure the axial displacement of the front end face of the rotor shaft 1 and is installed on the outer end face of the front bearing assembly 2. The integrated rear end cover 8 has a built-in multi-channel AD conversion module and a signal processing module.

[0025] It should be noted that rotor shaft 1 is made of 38CrMoAlA nitrided steel with a surface nitrided layer thickness of 0.3-0.5mm and a hardness ≥1200HV, combining core toughness with high surface wear resistance. The dense nitride hard phase formed by the nitrided layer can resist surface wear and fatigue cracks during high-speed rotation, while the hardenability of the material itself ensures the overall strength of the shaft, making it suitable for high-speed (e.g., above 10000rpm) milling operations. This design can improve the service life of rotor shaft 1 and reduce the surface friction coefficient, reducing spindle thermal deformation caused by frictional heat.

[0026] It should be noted that: front bearing assembly 2 and rear bearing assembly 9 are respectively sleeved at both ends of rotor shaft 1. Both front bearing assembly 2 and rear bearing assembly 9 are double-row angular contact ceramic bearings. The preload is adjusted to 800±50N by hydraulic cylinder. Compared with traditional steel bearings, it has the following advantages: the density of ceramic balls is 1 / 3 that of steel, which reduces centrifugal force and heat generation during high-speed operation. With a precise preload of 800±50N, it can suppress bearing clearance changes and maintain the radial runout of the spindle. The ceramic material has a high elastic modulus, which improves the rigidity of the spindle system after preload and has excellent wear resistance.

[0027] It should be noted that temperature sensor 4 is a PT1000 sensor, located 2mm from the stator winding 7 of the motor, with a temperature measurement range of 0-200℃ and an accuracy of ±0.3℃.

[0028] It should be noted that the vibration sensor 12 is a triaxial piezoelectric sensor with a bandwidth of 1-15kHz and a sensitivity of 50mV / g.

[0029] It should be noted that the thermal expansion sensor 13 is an eddy current sensor with a range of ±0.5 mm and a resolution of 0.2 μm.

[0030] By coordinating the array of miniature triaxial accelerometers, distributed thin-film temperature sensors 4, and non-contact eddy current displacement sensing units, the limitations of traditional single-point monitoring are overcome, enabling the synchronous capture of multi-dimensional signals such as vibration spectrum, temperature field distribution, and axial deformation, significantly improving the integrity of characteristic information under high-speed operating conditions.

[0031] In some embodiments, such as Figure 1 As shown, the main body 3 of the spindle housing is interference-fitted with the front sleeve 5 of the spindle housing, with an interference of 0.02-0.03mm; the rear end of the rotor shaft 1 is equipped with an encoder wheel 10 and an encoder 11, with the encoder 11 mounted on the outside of the encoder wheel 10 and a gap of 0.1±0.02mm.

[0032] In some embodiments, such as Figure 3 As shown, the rear end of the main spindle housing 3 is provided with an inlet 304 for coolant to flow in. The cooling system includes a spiral cooling channel 303, which is located inside the main spindle housing 3 and has a lead angle of 30°. The inner wall of the spiral cooling channel 303 is 0.5mm away from the motor stator 7. Coolant flows into the spiral cooling channel 303 through the inlet 304. It should be noted that the 30° lead angle spiral channel extends the coolant flow path and, together with the 0.5mm gap, forms turbulent heat transfer, thereby improving the stator heat dissipation efficiency and preventing insulation aging.

[0033] In some embodiments, such as Figure 1As shown, the cooling system includes an annular cooling sleeve 302 and a cooling channel 14. The annular cooling sleeve 302 is installed on the outside of the front bearing assembly 2, and the contact surface between the annular cooling sleeve 302 and the outer ring of the front bearing assembly 2 is provided with a microgroove structure with a depth of 0.2 mm and a spacing of 2 mm. The annular cooling sleeve 302 is connected to the spiral cooling channel 303 through the cooling channel 14. It should be noted that the microgroove structure of the annular cooling sleeve 302 increases the heat dissipation area.

[0034] In some embodiments, such as Figure 3 As shown, the exhaust system includes several vent holes 305 that run through the front and rear. The several vent holes 305 are arranged at equal intervals around the central axis of the rotor shaft 1. It should be noted that the exhaust system drives the heat of the encoder 11 at the rear end of the main shaft, bearings and other parts to be discharged. In conjunction with the cooling system, the overall heat dissipation efficiency is improved, and the air pressure rise caused by internal temperature rise is avoided.

[0035] There are three vent holes 305, which are arranged to run through the front and back and are distributed at 120° circumferential intervals around the central axis of rotor shaft 1.

[0036] In some embodiments, such as Figure 2 As shown, the signal processing module is connected to the multi-channel AD conversion module through the PCIe interface. The multi-channel AD conversion module includes a temperature AD converter, a vibration signal AD converter, and a displacement signal AD converter. The temperature AD converter samples the temperature sensor 4, the vibration signal AD converter samples the vibration sensor 12, and the displacement signal AD converter samples the thermal expansion sensor 13.

[0037] It should be noted that the temperature AD converter has a sampling rate of 2kHz; the vibration signal AD converter has a sampling rate of 100kHz; the displacement signal AD converter has a sampling rate of 20kHz; and the signal processing module uses the Xilinx Zynq-7020 chip, which integrates FFT spectrum analysis and wavelet packet decomposition algorithm to achieve synchronous fusion of multi-source data.

[0038] It should be noted that: the encoder 11 feeds back real-time rotational speed, drive motor current, ambient temperature, spindle elongation, and vibration; and generates a dynamic threshold for the effective value of vibration velocity (VRMS) based on the random forest algorithm, with an update cycle of 0.5 seconds; when 5 consecutive sampling points exceed the limit, a three-level warning (warning / alarm / emergency stop) is triggered.

[0039] The same or similar parts between the various embodiments in this specification can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments.

[0040] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A milling electric spindle with built-in integrated sensors, comprising a rotor shaft (1), a front bearing assembly (2), a spindle housing body (3), a motor stator (7), a front sleeve of the spindle housing (5), an integrated rear end cover (8), multiple sensors, a cooling system, and an exhaust system, characterized in that: The multi-sensor includes a temperature sensor (4), a vibration sensor (12), and a thermal elongation sensor (13); The temperature sensor (4) is used to monitor the temperature of the motor stator (7), and the temperature sensor (4) is installed in the radial hole (301) of the main shaft housing body (3); The vibration sensor (12) is used to collect the vibration signal of the front bearing assembly (2), and the vibration sensor (12) is installed in the axial hole (501) of the front sleeve (5) of the spindle housing; The thermal expansion sensor (13) is used to measure the axial displacement of the front end face of the rotor shaft (1), and the thermal expansion sensor (13) is installed on the outer end face of the front bearing assembly (2); The integrated back cover (8) has a built-in multi-channel AD conversion module and signal processing module.

2. A milling electric spindle with a built-in integrated sensor according to claim 1, characterized in that: The main body (3) of the spindle housing is interference-fitted with the front sleeve (5) of the spindle housing, with an interference of 0.02-0.03mm; the rear end of the rotor shaft (1) is equipped with an encoder wheel (10) and an encoder (11), the encoder (11) is installed on the outside of the encoder wheel (10), and the gap between them is 0.1±0.02mm.

3. A milling electric spindle with a built-in integrated sensor according to claim 1, characterized in that: The main spindle housing body (3) has an inlet (304) for coolant to flow in at the rear end. The cooling system includes a spiral cooling channel (303), which is located inside the main spindle housing body (3) and has a lead angle of 30°. The gap between the inner wall of the spiral cooling channel (303) and the motor stator (7) is 0.5 mm. Coolant flows into the spiral cooling channel (303) through the inlet (304).

4. A milling electric spindle with a built-in integrated sensor according to claim 3, characterized in that: The cooling system includes an annular cooling sleeve (302) and a cooling channel (14). The annular cooling sleeve (302) is installed on the outside of the front bearing assembly (2), and the contact surface between the annular cooling sleeve (302) and the outer ring of the front bearing assembly (2) is provided with a microgroove structure with a depth of 0.2 mm and a spacing of 2 mm. The annular cooling sleeve (302) is connected to the spiral cooling channel (303) through the cooling channel (14).

5. A milling electric spindle with a built-in integrated sensor according to claim 1, characterized in that: The exhaust system includes a plurality of vent holes (305) that run through the front and back, and the plurality of vent holes (305) are arranged at equal intervals around the central axis of the rotor shaft (1).

6. A milling electric spindle with a built-in integrated sensor according to claim 1, characterized in that: The signal processing module is connected to the AD conversion module via a PCIe interface. The AD conversion module includes a temperature AD converter, a vibration signal AD converter, and a displacement signal AD converter. The temperature AD converter samples the temperature sensor (4), the vibration signal AD converter samples the vibration sensor (12), and the displacement signal AD converter samples the thermal elongation sensor (13).

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