Axial bearing reinforced main shaft structure

Abstract

The invention discloses an axial bearing enhanced main shaft structure, and relates to the technical field of electric spindles, the axial bearing enhanced main shaft structure comprises a main shaft structure and a pressure control system, the main shaft structure comprises a main shaft shell, a shaft core arranged in the main shaft shell and a bearing arranged on the periphery of the shaft core in a sleeving mode, and the shaft core is rotatably connected with the main shaft shell through the bearing; the pressure control system is communicated with the main shaft shell, air pressure can be applied to the rear end face of the shaft core when the shaft core bears bearing force so as to offset the axial bearing force borne by the bearing, the structure is simple, the axial bearing of the main shaft can be dynamically balanced, the axial bearing capacity of the main shaft is improved, and the use requirement for large axial loads can be met.

Description

Technical Field

[0001] This invention relates to the field of electric spindle technology, and in particular to an axially load-bearing reinforced spindle structure. Background Technology

[0002] Electric spindles are widely used in various machine tools due to their convenient installation, compact structure, light weight, low vibration, high speed, high machining accuracy, and stable machining results. As a core functional component of machine tools, the performance of the electric spindle directly determines the technical level of various key technical indicators of the machine tool equipment, such as load capacity, power, torque, thermal expansion, etc.

[0003] Among the various specifications of electric spindles, one factor significantly impacts customer machining results and capabilities: spindle axial load. A higher axial load generally requires larger bearings; larger bearings result in lower spindle speeds, which in turn cannot meet the demands of high-speed machining. Conversely, smaller bearings allow for higher speeds, facilitating high-speed machining, but at the cost of lower axial loads, making it unsuitable for handling heavy axial loads. Furthermore, axial loads directly affect the bearings, causing overheating and impacting their fatigue life. Therefore, excessive axial loads restrict spindle selection and shorten spindle lifespan. Achieving a balance between speed and load significantly improves machine tool machining margins and capabilities, enhancing product competitiveness.

[0004] Currently, there are several main methods to address the axial load problem of spindles: ① Separating axial and radial loads, with axial load primarily handled at low speeds, using large-diameter or large-contact-angle bearings; ② Designing a spring preload adjustment structure. At high speeds and low stiffness, the bearing is adjusted to a small preload, resulting in low stiffness and high speed, suitable for high-speed machining. At low speeds and high stiffness, the bearing is adjusted to a large preload, resulting in high stiffness but low usable speed, suitable for low-speed machining. Both of these commonly used improvement methods have their advantages, but also significant drawbacks. Separating axial and radial loads, requiring dedicated machines, necessitates purchasing more equipment and has low integration. The bearing preload adjustment structure has a complex design and offers limited improvement in axial load, failing to meet the demands of large axial load applications. Summary of the Invention

[0005] The purpose of this invention is to provide an axial load-bearing enhanced spindle structure that is simple in structure, can dynamically balance the axial load of the spindle, improves the axial load capacity of the spindle, can meet the requirements of large axial loads, and solves the problems existing in the prior art.

[0006] To achieve the above objectives, the present invention provides the following solution: This invention provides an axial load-bearing reinforced spindle structure, including a spindle structure and a pressure control system. The spindle structure includes a spindle housing, a spindle core disposed inside the spindle housing, and a bearing sleeved on the outer periphery of the spindle core. The spindle core is rotatably connected to the spindle housing via the bearing. The pressure control system is connected to the spindle housing and can apply air pressure to the rear end face of the spindle core when the spindle core is subjected to load, so as to counteract the axial load borne by the bearing.

[0007] In some embodiments, the pressure control system includes an air intake device, wherein the rear end face of the shaft core and the top cover of the spindle housing form a pressure cavity, and the output end of the air intake device passes through the top cover to deliver gas into the pressure cavity and apply the air pressure to the rear end face of the shaft core.

[0008] In some embodiments, the pressure control system further includes a pressure-holding structure and a pressure-relieving structure. The pressure-holding structure is disposed inside the spindle housing and sleeved on the outer periphery of the rear end of the spindle core. The pressure chamber is a non-closed pressure chamber including an opening. The pressure-holding structure is disposed at the opening to maintain the air pressure inside the pressure chamber. The pressure-holding structure is spaced apart from the rear end of the spindle core to form the opening. The pressure-relieving structure is disposed on the part of the spindle housing outside the pressure chamber and communicates with the opening so that the pressure chamber communicates with the atmosphere through the pressure-relieving structure and the opening.

[0009] In some embodiments, the outer periphery of the pressure-holding structure is connected to the top cover, and the inner periphery of the pressure-holding structure is provided with an annular pressure equalizing groove. The annular pressure equalizing groove is arranged along the circumference of the pressure-holding structure, and multiple annular pressure equalizing grooves are arranged along the axial direction of the shaft core. The pressure control system further includes a pressure detection device, the probe of which extends into the pressure chamber to detect the value of the air pressure.

[0010] In some embodiments, the width of the annular equalizing groove gradually decreases from the opening to the bottom.

[0011] In some embodiments, the shaft core includes a balance disc and a shaft core body coaxially connected, the balance disc being connected to the rear end of the shaft core body; the balance disc includes a connecting section and a balancing section coaxially arranged, the balancing section being sleeved within the pressure-holding structure, the outer periphery of the balancing section being spaced apart from the inner ring of the pressure-holding structure, the side of the balancing section near the shaft core body abutting against the rear end face of the shaft core body, and the side of the balancing section away from the shaft core body having a balancing hole; the connecting section is disposed on the side of the balancing section near the shaft core body, and the connecting section is used to connect to the shaft core body.

[0012] In some embodiments, the spindle housing includes a housing body, a rear bearing housing, a front cover, and a dust cover. A stator is connected to the inner wall of the housing body, with the axis of the stator collinear with the axis of the spindle core. A rotor is sleeved on the spindle core body, and the stator is sleeved on the outer circumference of the rotor. When energized, the stator provides rotational driving force to the rotor, driving the spindle core body to rotate. The rear bearing housing is connected to one end of the housing body. The bearing includes a rear bearing and a front bearing. The inner wall of the rear bearing housing is connected to the outer ring of the rear bearing, allowing the spindle core body to rotate relative to the rear bearing housing. The top cover is connected to the end of the rear bearing housing away from the housing body. The pressure-holding structure is connected to the end of the inner ring of the top cover near the rear bearing housing. One end of the device is connected to a rear end cover, which has an air inlet for supplying air to the air intake device and a pressure measuring hole for the pressure detection device to detect the air pressure. The top cover, the rear end cover, and the balance disc form the pressure chamber. The front cover of the machine body is connected to the other end of the main body of the housing. The inner wall of the main body of the housing near the front cover is connected to the outer ring of the front bearing. A first limiting step is provided circumferentially on the inner wall of the main body of the housing. One end of the front bearing abuts against the first limiting step, and the other end of the front bearing abuts against the side of the front cover of the machine body near the main body of the housing. The dust cover is connected to the end of the front cover of the machine body away from the main body of the housing. The dust cover has an extension hole for the shaft core body to extend out. The inner wall of the extension hole is spaced apart from the shaft core body.

[0013] In some embodiments, a second limiting step is provided circumferentially on the inner ring of the rear bearing housing near one end of the housing body, and a preload spring arranged axially along the shaft body is provided between the second limiting step and the rear bearing.

[0014] In some embodiments, the top cover, the rear bearing seat, the housing body, and the front cover of the machine body are provided with communicating gas channels. The dust cover is also provided with a plurality of air blowing holes arranged along the circumference of the dust cover and distributed radially along the dust cover. Each air blowing hole is connected to the gas channel. The gas sealing gas enters through the gas channel, is blown out from the air blowing hole, and is blown out through the gap between the dust cover and the shaft body to form a gas sealing structure.

[0015] In some embodiments, the dust cover has an extension section at one end near the front cover of the machine body, the extension section extending into the inner ring of the front cover of the machine body, and the outer wall of the extension section being connected to the inner wall of the front cover of the machine body; the outer wall of the extension section is provided with a first air equalization groove along the circumference of the dust cover, the first air equalization groove being connected to the gas channel, and the inner wall of the extension section is provided with a second air equalization groove along the circumference of the dust cover, and each of the air blowing holes is connected to both the first air equalization groove and the second air equalization groove.

[0016] The present invention achieves the following technical effects compared to the prior art: The axial load-bearing enhanced spindle structure provided by this invention applies air pressure to the rear end face of the spindle core by setting a pressure control system, so that the air pressure cancels out the axial load force borne by the bearing. The structure is simple, reduces the load on the bearing, improves the axial machining capability of the spindle and the service life of the bearing, and can meet the needs of large axial loads. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a cross-sectional view of the overall structure of the axial load-bearing reinforced spindle structure in the embodiments provided by the present invention; Figure 2 A schematic diagram illustrating the working principle of the axial load-bearing reinforced spindle structure in the embodiments provided by the present invention; Figure 3 for Figure 1 A magnified view of part A in the middle; Figure 4 A cross-sectional view of the toothed ring in an embodiment of the present invention; Figure 5 This is a schematic diagram of the overall structure of the balance disc in an embodiment of the present invention; Figure 6 This is a schematic diagram of the overall structure of the rear end cover in an embodiment of the present invention; Figure 7 A top view of the rear end cover in an embodiment provided by the present invention; Figure 8 This is a schematic diagram of the gas seal structure in an embodiment of the present invention; Figure 9 for Figure 8 A magnified view of part B in the middle section.

[0019] In the diagram: 100. Axial load-bearing reinforced spindle structure; 1. Spindle housing; 11. Housing body; 111. Stator; 12. Rear bearing seat; 13. Top cover; 14. Rear end cover; 141. Air inlet; 142. Pressure measuring hole; 15. Front cover of the machine body; 16. Dust cover; 161. First air equalization groove; 162. Air blowing hole; 163. Second air equalization groove; 17. Preload spring; 18. Gas passage; 2. Shaft core; 21. Shaft core body; 22. Balance disc; 221. Balance hole; 23. Rotor; 3. Rear bearing; 4. Front bearing; 5. Pressure control system; 51. Air compressor; 52. Pressure reducing valve; 53. Pressure gauge; 54. Grate ring; 541. Annular pressure equalization groove; 55. Pressure relief structure; F1. Axial load-bearing capacity; F2. Pressure. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] The purpose of this invention is to provide an axial load-bearing enhanced spindle structure that is simple in structure, can dynamically balance the axial load of the spindle, improves the axial load capacity of the spindle, can meet the requirements of large axial loads, and solves the problems existing in the prior art.

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the following description is provided in conjunction with the accompanying drawings. Figures 1-9 The present invention will be further described in detail below with reference to specific embodiments.

[0023] Example This embodiment provides an axially load-bearing reinforced spindle structure 100, for reference... Figures 1-2 The axial load-bearing enhanced spindle structure 100 provided in this embodiment includes a spindle structure and a pressure control system 5. The spindle structure includes a spindle housing 1, a spindle core 2 disposed inside the spindle housing 1, and a bearing sleeved on the outer periphery of the spindle core 2. The spindle core 2 is rotatably connected to the spindle housing 1 via the bearing. The pressure control system 5 is connected to the spindle housing 1 and can apply air pressure to the rear end face of the spindle core 2 when the spindle core 2 is subjected to load, so as to offset the axial load borne by the bearing. The axial load-bearing enhanced spindle structure 100 provided in this embodiment applies air pressure to the rear end face of the spindle core 2 by setting the pressure control system 5, so that the air pressure offsets the axial load borne by the bearing. The structure is simple, reduces the load on the bearing, improves the axial machining capability of the spindle and the service life of the bearing, and can meet the needs of large axial load applications.

[0024] In some implementations, reference Figure 2The pressure control system 5 includes an air intake device. A pressure chamber is formed between the rear end face of the shaft core 2 and the top cover 13 of the main shaft housing 1. The output end of the air intake device passes through the top cover 13 to deliver gas into the pressure chamber and apply air pressure to the rear end face of the shaft core 2. In this embodiment, a pressure chamber is formed between the rear end face of the shaft core 2 and the top cover 13 of the main shaft housing 1. By allowing the output end of the air intake device to pass through the top cover 13 and communicate with the pressure chamber, gas can be delivered into the pressure chamber, increasing the air pressure within the chamber. This allows the air pressure applied to the rear end face of the shaft core 2 to offset the axial load on the bearing. The structure is simple and easy to implement. In this embodiment, the air intake device includes an air compressor 51 capable of outputting high-pressure air. In other embodiments, the air compressor 51 can also be used in conjunction with a filter to produce clean high-pressure gas.

[0025] In some implementations, reference Figure 2 The pressure control system 5 also includes a pressure-holding structure and a pressure-relief structure 55. The pressure-holding structure is located inside the spindle housing 1 and sleeved around the rear end of the spindle core 2. The pressure chamber is a non-closed pressure chamber including an opening. The pressure-holding structure is located at the opening to maintain the air pressure inside the pressure chamber. The pressure-holding structure is spaced apart from the rear end of the spindle core 2 to form the opening. The pressure-relief structure 55 is located on the part of the spindle housing 1 outside the pressure chamber and communicates with the opening, so that the pressure chamber is connected to the atmosphere through the pressure-relief structure 55 and the opening. The rear end of the spindle core 2 needs to have a rotational clearance with the surrounding structure to avoid frictional resistance when the spindle core 2 rotates. Therefore, this embodiment provides a pressure-holding structure to slow down the loss of air pressure inside the pressure chamber and allow gas to enter the pressure chamber to form a stable pressure. In this embodiment, the pressure relief structure 55 is located outside the pressure chamber on the spindle housing 1, so that the gas in the pressure chamber can flow out through the opening and the pressure relief structure 55. This ensures that the gas pressure in the pressure chamber is stable, which can offset the axial load on the bearing, while not affecting the rotation of the spindle core 2, so that the spindle core 2 can work stably and further improve the axial machining capability of the spindle.

[0026] In some implementations, reference Figures 2-4The outer periphery of the pressure-holding structure is connected to the top cover 13, and the inner periphery of the pressure-holding structure is provided with an annular pressure equalizing groove 541. The annular pressure equalizing groove 541 is arranged along the circumference of the pressure-holding structure, and multiple annular pressure equalizing grooves 541 are arranged along the axial direction of the shaft core 2. The pressure control system 5 also includes a pressure detection device, the probe of which extends into the pressure chamber to detect the air pressure value. Specifically, in this embodiment, the pressure-holding structure is a toothed ring 54, which is connected to the top cover 13 by screws. The end face of the top cover 13 is provided with a sealing structure, specifically, the top cover 13 has an axially opened sealing groove, and a sealing ring is provided in the sealing groove to prevent gas from leaking from the gap between the toothed ring 54 and the top cover 13. In this embodiment, the single-sided clearance between the toothed ring 54 and the rear end of the shaft core 2 is set to 0.03-0.08mm to avoid large swaying when the shaft core 2 rotates at high speed. Too small a clearance can easily cause interference and jamming of the shaft core 2, or too large a clearance can lead to significant pressure leakage, making it impossible to maintain stable air pressure and thus failing to offset the axial load borne by the bearing in real time. Four annular pressure equalizing grooves 541 are provided along the axial direction of the shaft core 2 on the inner circumference of the toothed ring 54. In some other embodiments, two or more annular pressure equalizing grooves 541 may be provided. When gas leaks from the opening of the pressure chamber, the gas velocity and pressure are high near the edge of the annular pressure equalizing groove 541. After passing through the annular pressure equalizing groove 541, the gas pressure decreases and the flow velocity slows down, forming turbulence as the airflow passes through, effectively trapping the leaking gas and creating a pressure zone. Multiple annular pressure equalizing grooves 541 progressively reduce the pressure of the leaking gas. After multiple pressure relief processes, multiple pressure zones with gradually decreasing pressure are formed. This pressure reduction effectively lowers the gas leakage rate and flow rate, improving pressure holding efficiency. In some other embodiments, the toothed ring 54 can be integrally formed with the top cover 13 to reduce the assembly steps of the toothed ring 54. In this embodiment, refer to... Figure 2 The intake device also includes a pressure reducing valve 52, which, in conjunction with the air pressure value detected by the pressure detection device in the pressure chamber, adjusts the gas delivered by the intake device in real time. This real-time adjustment of the air pressure value in the pressure chamber ensures that the pressure F2 generated by the air pressure on the rear end face of the shaft core 2 can stably counteract the axial load F1 borne by the bearing. P is the pressure in the pressure chamber, and S is the area of ​​the rear end face of the shaft core 2. Force calculations are performed to determine the pressure F2 generated by the air pressure at the rear end face of the shaft core 2. Simultaneously, by controlling the air pressure P, closed-loop control of pressure F2 can be achieved, making adjustment simple and convenient, further improving the axial machining capability of the spindle and the service life of the bearings. The pressure detection device includes a pressure gauge 53. In some other embodiments, the pressure detection device can also employ other devices capable of detecting the air pressure within the pressure chamber, such as a pressure sensor. The housing body 11 has an air inlet 141 and a pressure measuring hole 142. The pressure detection device measures the pressure chamber pressure through the pressure measuring hole. In some other embodiments, the pressure chamber pressure can also be measured through the air inlet 141, and the pressure measuring hole 142 can also be located on the side wall of other structures enclosing the pressure chamber.

[0027] In some implementations, reference Figure 4 The width of the annular pressure equalizing groove 541 gradually decreases from the opening to the bottom. By setting the width of the annular pressure equalizing groove 541 to gradually decrease from the opening to the bottom, an annular pressure equalizing groove 541 with a larger outer diameter and a smaller inner diameter is formed. When the gas flows through the annular pressure equalizing groove 541, the flow is smooth and the eddies formed are smaller. Therefore, the local pressure loss is also smaller, which can effectively maintain the pressure in the pressure chamber. At the same time, the gas flows out more smoothly and can also form a more stable support force on the shaft core 2, improving the machining stability of the shaft core 2.

[0028] In some implementations, reference Figure 1 and Figure 5The shaft core 2 includes a balance disc 22 and a shaft core body 21 coaxially connected. The balance disc 22 is connected to the rear end of the shaft core body 21. The balance disc 22 includes a connecting section and a balancing section coaxially arranged. The balancing section is sleeved inside the pressure-holding structure. The outer periphery of the balancing section is spaced apart from the inner ring of the pressure-holding structure. The side of the balancing section near the shaft core body 21 abuts against the rear end face of the shaft core body 21. The side of the balancing section away from the shaft core body 21 has a balancing hole 221. The connecting section is arranged on the side of the balancing section near the shaft core body 21 and is used to connect with the shaft core body 21. Specifically, in this embodiment, the connecting section includes a first conical section and a first threaded section. A connecting hole is provided on the shaft core body 21. The connecting hole includes a second conical section and a second threaded section. The first and second conical sections have the same cone angle. The threads of the first and second threaded sections are engaged. The connecting section is screwed into the connecting hole. The first conical section slides along the second conical section until the first conical section presses against the second conical section. This can effectively improve the coaxiality of the balance disc 22 and the shaft core body 21. At the same time, it can also avoid the problem of increased runout of the outer edge of the balance disc 22 caused by centrifugal deformation when the shaft core body 21 rotates at high speed. In addition, the side of the balance section close to the shaft core body 21 contacts the end face of the shaft core body 21, which can ensure the perpendicularity of the end face of the balance disc 22 relative to the shaft core body 21 after installation. By opening a balancing hole 221 on the side of the balancing section away from the shaft core body 21, and distributing the balancing hole 221 circumferentially along the balancing disc 22, the imbalance of the shaft core 2 caused by machining dimensions, coaxiality, and assembly coaxiality can be balanced, ensuring that the shaft core body 21 remains in a low vibration state when rotating at high speed, thus improving machining stability. In some other embodiments, the first conical section in the connecting section can be replaced with a cylindrical section, and the second conical section of the connecting hole can be replaced with a circular hole section.

[0029] In some implementations, reference Figure 1 and Figures 6-7The main shaft housing 1 includes a housing body 11, a rear bearing seat 12, a front cover 15, and a dust cover 16. A stator 111 is connected to the inner wall of the housing body 11. The axis of the stator 111 is collinear with the axis of the shaft core 2. The rotor 23 is sleeved on the shaft core body 21, and the stator 111 is sleeved on the outer circumference of the rotor 23. When the stator 111 is energized, it provides rotational driving force to the rotor 23, driving the shaft core body 21 to rotate. The rear bearing seat 12 is connected to one end of the housing body 11. The bearings include a rear bearing 3 and a front bearing 4. The inner wall of the rear bearing seat 12 is connected to the outer ring of the rear bearing 3, allowing the shaft core body 21 to rotate relative to the rear bearing seat 12. A top cover 13 is connected to the end of the rear bearing seat 12 away from the housing body 11. A pressure-holding structure is connected to the end of the inner ring of the top cover 13 near the rear bearing seat 12. One end of the bearing housing 12 is connected to the rear end cover 14. The rear end cover 14 has an air inlet 141 for supplying air to the air intake device and a pressure measuring hole 142 for the pressure detection device to detect the air pressure value. The top cover 13, the rear end cover 14, and the balance disc 22 form a pressure chamber. The front cover 15 of the machine body is connected to the other end of the housing body 11. The inner wall of the housing body 11 near the front cover 15 is connected to the outer ring of the front bearing 4. The inner wall of the housing body 11 is provided with a first limiting step in the circumferential direction. One end of the front bearing 4 abuts against the first limiting step, and the other end of the front bearing 4 abuts against the side of the front cover 15 near the housing body 11. The dust cover 16 is connected to the end of the front cover 15 away from the housing body 11. The dust cover 16 has an extension hole for the shaft core body 21 to extend out. The inner wall of the extension hole is spaced apart from the shaft core body 21. In this embodiment, the pressure relief structure 55 is a pressure relief channel formed on the rear bearing housing 12 and the top cover 13. The outlet of the pressure relief channel is located on the end face of the top cover 13 away from the rear bearing housing 12. Gas flows out from the pressure chamber through the opening and into the atmosphere through the pressure relief channel. The rotor 23 is interference-fitted with the shaft core body 21 to ensure synchronous rotation of the rotor 23 and the shaft core body 21. The rotor 23 is driven by the energized stator 111 to drive the shaft core body 21 to rotate. The rear end of the shaft core body 21 is located inside the spindle housing 1, and the front end of the shaft core body 21 extends out of the dust cover 16. The front end of the shaft core body 21 is used to connect with the machining tool.

[0030] In some implementations, reference Figure 1 A second limiting step is circumferentially provided on the inner ring of the rear bearing housing 12 near the end of the housing body 11. A preload spring 17 is arranged axially along the shaft core body 21 between the second limiting step and the rear bearing 3. In this embodiment, the rear bearing 3 is sleeved on the shaft core body 21, and an adjusting nut is threadedly connected to the shaft core body 21. One end of the rear bearing 3 abuts against the adjusting nut, and the other end abuts against the preload spring 17 to apply a preset preload force to the preload spring 17, which greatly reduces the axial runout and movement of the rear bearing 3, thereby achieving high-precision rotation of the shaft core body 21.

[0031] In some implementations, reference Figure 8 The top cover 13, rear bearing seat 12, housing body 11, and front cover 15 of the machine body are provided with a connected gas channel 18. The dust cover 16 is also provided with multiple air blowing holes 162 arranged radially along the circumference of the dust cover 16. Each air blowing hole 162 is connected to the gas channel 18. The sealing gas enters through the gas channel 18, is blown out from the air blowing hole 162, and is blown out through the gap between the dust cover 16 and the shaft core body 21 to form a sealing structure. In this embodiment, the sealing gas inlet of the gas channel 18 is located on the end face of the top cover 13. By setting the sealing mechanism, foreign objects can be prevented from entering through the gap between the dust cover 16 and the shaft core body 21, thereby avoiding the problem of reduced machining stability caused by interference and friction between the shaft core body 21 and the housing body 11 due to foreign objects entering the gap. This improves the machining stability of the shaft core body 21 and further enhances the axial machining capability of the axially load-bearing reinforced spindle structure 100.

[0032] In some implementations, reference Figure 9 The dust cover 16 has an extension section at one end near the front cover 15 of the machine body. The extension section extends into the inner ring of the front cover 15 of the machine body, and the outer wall of the extension section is connected to the inner wall of the front cover 15 of the machine body. The outer wall of the extension section is provided with a first air equalization groove 161 along the circumference of the dust cover 16. The first air equalization groove 161 is connected to the gas channel 18. The inner wall of the extension section is provided with a second air equalization groove 163 along the circumference of the dust cover 16. Each air blowing hole 162 is connected to the first air equalization groove 161 and the second air equalization groove 163. By providing an extension section on the dust cover 16 and having a first gas equalization groove 161 on the outer wall of the extension section that communicates with the gas channel 18, the sealing gas can be evenly introduced into each air blowing hole 162. Furthermore, by having a second gas equalization groove 163 on the inner wall of the extension section that communicates with each air blowing hole 162, the sealing gas can be evenly filled in the gap between the dust cover 16 and the shaft core body 21. This not only prevents foreign objects from entering the gap between the dust cover 16 and the shaft core body 21, but also provides a supporting force to the shaft core body 21 with the pressure generated by the evenly flowing sealing gas, making the shaft core body 21 more effective in resisting eccentric movement and further increasing the processing stability of the shaft core body 21.

[0033] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. An axially load-bearing reinforced spindle structure, characterized in that: include: A spindle structure includes a spindle housing, a spindle core disposed inside the spindle housing, and a bearing sleeved on the outer periphery of the spindle core, wherein the spindle core is rotatably connected to the spindle housing via the bearing; and A pressure control system, which is connected to the spindle housing, is capable of applying air pressure to the rear end face of the spindle core when the spindle core is subjected to load, so as to counteract the axial load force borne by the bearing.

2. The axial load-bearing reinforced spindle structure according to claim 1, characterized in that: The pressure control system includes: An air intake device is provided, wherein the rear end face of the shaft core and the top cover of the main shaft housing form a pressure cavity, and the output end of the air intake device passes through the top cover to deliver gas into the pressure cavity and apply the air pressure to the rear end face of the shaft core.

3. The axial load-bearing reinforced spindle structure according to claim 2, characterized in that: The pressure control system also includes: A pressure-holding structure is disposed inside the spindle housing and sleeved on the outer periphery of the rear end of the spindle core. The pressure chamber is a non-closed pressure chamber including an opening. The pressure-holding structure is disposed at the opening to maintain the air pressure within the pressure chamber. The pressure-holding structure is spaced apart from the rear end of the spindle core to form the opening. A pressure relief structure is provided on the part of the spindle housing other than the pressure cavity and communicates with the opening so that the pressure cavity is connected to the atmosphere through the pressure relief structure and the opening.

4. The axial load-bearing reinforced spindle structure according to claim 3, characterized in that: The outer periphery of the pressure-holding structure is connected to the top cover, and the inner periphery of the pressure-holding structure is provided with an annular pressure equalizing groove. The annular pressure equalizing groove is arranged along the circumferential direction of the pressure-holding structure, and multiple annular pressure equalizing grooves are arranged along the axial direction of the shaft core. The pressure control system also includes a pressure detection device, the probe of which extends into the pressure chamber to detect the value of the air pressure.

5. The axial load-bearing reinforced spindle structure according to claim 4, characterized in that: The width of the annular equalizing groove gradually decreases from the opening to the bottom.

6. The axial load-bearing reinforced spindle structure according to claim 4 or 5, characterized in that: The shaft core includes a balance disc and a shaft core body coaxially connected, and the balance disc is connected to the rear end of the shaft core body; The balance disc includes a connecting section and a balance section arranged coaxially. The balance section is sleeved inside the pressure-holding structure. The outer periphery of the balance section is spaced apart from the inner ring of the pressure-holding structure. The side of the balance section near the shaft core body abuts against the rear end face of the shaft core body. The side of the balance section away from the shaft core body has a balance hole. The connecting section is located on the side of the balance section near the shaft core body, and the connecting section is used to connect with the shaft core body.

7. The axial load-bearing reinforced spindle structure according to claim 6, characterized in that: The spindle housing includes: The housing body has a stator connected to its inner wall. The axis of the stator is collinear with the axis of the shaft core. The rotor is sleeved on the shaft core body, and the stator is sleeved on the outer periphery of the rotor. When the stator is energized, it provides rotational driving force to the rotor to drive the shaft core body to rotate. A rear bearing housing is connected to one end of the housing body. The bearing includes a rear bearing and a front bearing. The inner wall of the rear bearing housing is connected to the outer ring of the rear bearing so that the shaft core body can rotate relative to the rear bearing housing. The top cover is connected to the end of the rear bearing housing away from the housing body. The pressure-holding structure is connected to the end of the inner ring of the top cover near the rear bearing housing. The rear end cover is connected to the end of the inner ring of the top cover away from the rear bearing housing. The rear end cover has an air inlet for supplying air to the air inlet device and a pressure measuring hole for the pressure detection device to detect the air pressure value. The top cover, the rear end cover, and the balance disc form the pressure chamber. A front cover is connected to the other end of the main body of the housing. The inner wall of the main body of the housing near the front cover is connected to the outer ring of the front bearing. A first limiting step is provided circumferentially on the inner wall of the main body of the housing. One end of the front bearing abuts against the first limiting step, and the other end of the front bearing abuts against the side of the front cover near the main body of the housing. A dust cover is connected to the end of the front cover of the machine body away from the main body of the housing. The dust cover has an extension hole for the shaft core body to extend out, and the inner wall of the extension hole is spaced apart from the shaft core body.

8. The axial load-bearing reinforced spindle structure according to claim 7, characterized in that: A second limiting step is provided circumferentially on the inner ring of the rear bearing housing near one end of the housing body, and a preload spring is provided between the second limiting step and the rear bearing, arranged axially along the shaft body.

9. The axial load-bearing reinforced spindle structure according to claim 8, characterized in that: The top cover, the rear bearing seat, the housing body, and the front cover of the machine body are provided with a connected gas channel. The dust cover is also provided with a plurality of air blowing holes arranged along the circumference of the dust cover and distributed radially along the dust cover. Each air blowing hole is connected to the gas channel. The gas sealing gas enters through the gas channel, is blown out from the air blowing hole, and is blown out through the gap between the dust cover and the shaft core body to form a gas sealing structure.

10. The axial load-bearing reinforced spindle structure according to claim 9, characterized in that: The dust cover has an insertion section at one end near the front cover of the machine body. The insertion section extends into the inner ring of the front cover of the machine body, and the outer wall of the insertion section is connected to the inner wall of the front cover of the machine body. The outer wall of the extension section is provided with a first gas equalization groove along the circumference of the dust cover. The first gas equalization groove is connected to the gas channel. The inner wall of the extension section is provided with a second gas equalization groove along the circumference of the dust cover. Each of the air blowing holes is connected to the first gas equalization groove and the second gas equalization groove.

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