Ultrasonic air floatation motorized spindle unit

Abstract

The utility model relates to the technical field of machining, and discloses an ultrasonic air flotation motorized spindle unit which comprises a body and a spindle core arranged in the body, a driving assembly, an energy transmission assembly and a first air flotation assembly are further arranged in the body and located on the periphery of the spindle core, and a cutter handle and an energy converter are arranged at the end of the spindle core respectively. The driving assembly is used for driving the shaft core to rotate in the body; the first air floatation assembly corresponds to the cutter handle in position and is used for forming an air film on the periphery of the shaft core; the energy transmission assembly is arranged between the driving assembly and the first air flotation assembly, and the energy transmission assembly is connected with the transducer. According to the utility model, the distance between the energy transmission assembly and the transducer is shortened, the structural rigidity and the dynamic balance performance of the shaft core are improved, and the working efficiency and the precision of the whole main shaft are further improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to machining technical field more specifically, and particularly relates to an ultrasonic air floatation electric main shaft unit. BACKGROUND

[0002] Ultrasonic machining is widely used in nonmetallic, hard and brittle materials and micro-hole and deep-hole machining because the tool tip has ultrasonic energy. When machining ceramic and other hard and brittle materials, high rotating speed is often required, and the tool must have sufficient cutting force and service life. Ordinary air floatation main shafts cannot guarantee good hole machining surface quality, and ultrasonic air floatation main shafts can meet the requirement of high quality.

[0003] The current ultrasonic air floatation main shaft structure, as disclosed in patent CN204315886U, places the conductive part at the tail end of the main shaft, which requires a deep wire hole to be machined on the shaft core, and the machining difficulty is great. The deviation of the deep hole position will affect the dynamic balance performance of the main shaft. At the same time, the tail end of the structure is in the form of a slip ring, which is prone to friction and wear of the slip ring at high rotating speed.

[0004] Although patent CN106141211A discloses an increase of a rotating conductive ring at the front end of the main shaft shell to transmit electric energy to the transducer assembly of the shaft core, the rotating conductive ring occupies a large space at the front end of the main shaft, which makes the air floatation part be placed behind and the overhanging length be too long, and the rigidity of the main shaft is insufficient. At the same time, the tool is clamped directly by the locking assembly, and only manual tool replacement can be performed. In the case of complex process, the tool needs to be frequently replaced, which affects the machining accuracy and efficiency. SUMMARY

[0005] The utility model aims at the technical problems existing in the prior art, and provides an ultrasonic air floatation electric main shaft unit, which can improve the structural rigidity and machining accuracy.

[0006] The utility model provides an ultrasonic air floatation electric main shaft unit, which comprises a body, a shaft core arranged in the body, a driving assembly, an energy transmission assembly and a first air floatation assembly arranged in the body and at the outer periphery of the shaft core, a tool handle and a transducer arranged at the end of the shaft core, and the driving assembly is used to drive the shaft core to rotate in the body.

[0007] The first air floatation assembly corresponds to the position of the tool handle, and is used to form an air film at the outer periphery of the shaft core. The energy transmission assembly is arranged between the driving assembly and the first air floatation assembly, and the energy transmission assembly is connected with the transducer.

[0008] Further, the driving assembly comprises a motor stator and a motor rotor, the motor rotor is sleeved on the outer periphery of the shaft core; the motor stator is arranged on the side of the motor rotor away from the shaft core, and a cooling jacket is arranged between the outer side wall of the motor stator and the inner side wall of the body.

[0009] Further, the first air floating assembly comprises a first air floating bearing, the first air floating bearing is connected with the body and is sleeved on the outer periphery of the shaft core, and a first gap is reserved between the first air floating bearing and the shaft core.

[0010] The body is provided with an axial air channel for introducing compressed gas, and the first air floating bearing is provided with a plurality of first radial holes, and the first radial holes are respectively connected with the first gap and the axial air channel.

[0011] Further, the energy transmission assembly comprises a wireless power receiving module and a wireless power supply module arranged radially along the shaft core, and the wireless power receiving module is connected with the shaft core; a channel is formed between the wireless power supply module and the wireless power receiving module, and the channel corresponds to and communicates with the first gap.

[0012] Further, the outer diameter of the wireless power receiving module is smaller than the inner diameter of the first air floating bearing, the two side walls of the wireless power supply module are respectively limited by the positioning convex parts on the first air floating bearing and the body, and are connected with the inner side wall of the body.

[0013] Further, the outer periphery of the end of the shaft core away from the shank is provided with a second air floating assembly, the second air floating assembly comprises a second air floating bearing and an air floating bushing, the second air floating bearing is connected with the body; the air floating bushing is arranged between the second air floating bearing and the shaft core, and the air floating bushing is connected with the shaft core; the second air floating bearing is used for forming an air film on the outer periphery of the air floating bushing.

[0014] Further, the first air floating assembly further comprises a thrust bearing sleeved on the outer periphery of the shaft core, and the outer periphery of the shaft core extends radially to form a limiting convex part; the thrust bearing and the first air floating bearing are arranged on the two sides opposite to the limiting convex part, and the side walls of the limiting convex part are respectively reserved with a second gap and a third gap.

[0015] Further, the first air floating bearing is further provided with a first axial hole communicated with the first radial hole and the third gap, and the thrust bearing is further provided with a plurality of second axial holes, and the second axial holes are respectively communicated with the axial air channel and the second gap.

[0016] Further, a spacing plate is arranged between the side walls opposite to the first air floating bearing and the thrust bearing, and the spacing plate is sleeved on the outer periphery of the limiting convex part.

[0017] Further, the tool changing assembly is used for clamping the tool holder and changing tools.

[0018] Compared with the prior art, the utility model has the advantages of:

[0019] The energy transmission assembly is arranged at the front end of the shaft core, the distance between the energy transmission assembly and the transducer can be shortened, the long wire hole is avoided to be machined on the shaft core, and the structural rigidity and dynamic balance performance of the shaft core are improved. The first air floating assembly is further arranged between the front end of the shaft core and the body, the air film is formed on the outer periphery of the shaft core, the shaft core is limited to prevent the shaft core from being deviated in the rotating process, the rotating stability of the shaft core is improved, and the working efficiency and precision of the air floating motorized spindle unit are further improved. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the scheme in the utility model, the following will briefly introduce the drawings needed to be used in the embodiment description, and obviously, the drawings in the following description are some embodiments of the utility model, and other drawings can be obtained by those skilled in the art without creative labor. Wherein:

[0021] Figure 1 It is a structural view of the ultrasonic air floating motorized spindle unit of the utility model.

[0022] Figure 2 It is a partial schematic view of the ultrasonic air floating motorized spindle unit of the utility model.

[0023] Figure 3 It is a partial schematic view of the first air floating assembly in the utility model.

[0024] Figure 4 It is another partial schematic view of the ultrasonic air floating motorized spindle unit of the utility model.

[0025] Wherein, 1-body, 2-shaft core, 3-driving assembly, 4-energy transmission assembly, 5-tool holder, 6-first air floating assembly, 7-end cover, 8-damping plug, 9-cooling jacket, 101-axial air channel, 11-separation plate, 12-second air floating bearing, 13-air floating bushing, 14-pull claw, 15-pull rod, 16-elastic member, 21-limiting convex part, 31-motor stator, 32-motor rotor, 41-wireless power receiving module, 42-wireless power supply module, 61-first air floating bearing, 612-first radial hole, 613-first axial hole, 614-first annular groove, 62-thrust bearing, 621-second axial hole, 622-second annular groove, 121-third axial hole, 122-second radial hole. DETAILED DESCRIPTION

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the specification herein is for describing particular embodiments only and is not intended to be limiting of the application. For example, the terms "length", "width", "upper", "lower", "left", "right", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like as can be directed to orientations or positions shown in the drawings are used for convenience and are not intended to be limiting as to the application.

[0027] The terms "comprise", "have" and any variations thereof in the specification and claims of the application and in the accompanying drawings mean "including, but not limited to" and not "consist of" or "composed of"; the terms "first", "second", and the like in the specification and claims of the application or in the accompanying drawings are used for distinguishing between similar objects and not necessarily describing a particular sequential or chronological order. In the specification and claims of the application and in the accompanying drawings, when an element is referred to as being "on" or "connected to" or "coupled to" another element, it can be directly on or connected or coupled to the other element or indirectly on or connected or coupled to the other element by another element. For example, when an element is referred to as being "connected to" another element, it can be directly or indirectly connected to the other element.

[0028] Further, reference being made herein to "embodiments" means that a specific feature, structure, or characteristic described in connection with an embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. It is expressly understood that the embodiments described herein are merely examples from a whole class of comparable embodiments which those skilled in the art will readily appreciate. It is also expressly understood that the scope of the application is not limited to the embodiments described herein but is only limited by the claims.

[0029] Referring to Figure 1 and Figure 2 The utility model provides a kind of ultrasonic air floatation electric main shaft unit, including body 1, shaft core 2, drive assembly 3, energy transmission assembly 4, tool holder 5 and first air floatation assembly 6;

[0030] Shaft core 2 is arranged in the cavity of body 1, and the end cavity and the outer periphery of shaft core 2 are respectively provided with tool holder 5 and transducer (not shown in the drawing);Drive assembly 3 is arranged between the outer peripheral surface of shaft core 2 and body 1, and drive assembly 3 can drive shaft core 2 to rotate in body 1;

[0031] The first gas floating assembly 6 is arranged on the outer periphery of the shaft core 2, and corresponds to the position of the tool holder 5, and is used to form a gas film on the outer periphery of the shaft core 2 to prevent the shaft core 2 from moving radially during rotation. The energy transmission assembly 4 is arranged between the driving assembly 3 and the first gas floating assembly 6, and is connected with the transducer, so that the gas floating spindle can realize ultrasonic machining.

[0032] In the embodiment, the energy transmission assembly 4 is arranged between the driving assembly 3 and the first gas floating assembly 6, so that the distance between the energy transmission assembly 4 and the transducer is greatly shortened, the shaft core 2 does not need to be machined with a complex deep hole, the dynamic balance performance is good, the space of the center through hole of the shaft core 2 is not occupied, and the structural rigidity of the shaft core 2 is improved.

[0033] In the embodiment, the first gas floating assembly 6 is arranged, so that a gas film can be formed on the outer wall of the shaft core 2, the radial position of the shaft core 2 is limited, the shaft core 2 is prevented from moving radially during machining, the friction is reduced, the rotating speed of the shaft core 2 is improved, the grinding force is reduced, and the machining precision of the gas floating spindle unit is improved.

[0034] Referring to Figure 2 The driving assembly 3 includes a motor stator 31 and a motor rotor 32. The motor rotor 32 is sleeved on the outer periphery of the shaft core 2 and is fixedly connected with the shaft core 2. The motor stator 31 is arranged on the side, away from the shaft core 2, of the motor rotor 32. A cooling jacket 9 is arranged between the outer wall of the motor stator 31 and the inner wall of the body 1. The motor stator 31 and the cooling jacket 9 are fixed to the inner wall of the body 1.

[0035] During work, the motor rotor 32 is driven to rotate the shaft core 2 by electrifying the motor stator 31. Since the motor stator 31 and the motor rotor 32 generate heat during work, the cooling jacket 9 can dissipate the heat, so as to ensure the reliability of the gas floating spindle unit.

[0036] In other embodiments, a cooling flow channel can be arranged on the body 1 instead of the cooling jacket 9. The cooling flow channel corresponds to the position of the driving assembly 3. Cooling liquid is introduced into the cooling flow channel, so as to dissipate the heat generated by the motor stator 31 and the motor rotor 32 during work, and ensure the reliability of the spindle.

[0037] Continuously referring to Figure 2 and Figure 3As shown in FIG. 1, the first gas float assembly 6 comprises a first gas float bearing 61, the outer side wall of the first gas float bearing 61 is sealingly connected with the inner side wall of the body 1, the first gas float bearing 61 is sleeved on the periphery of the shaft core 2, and a first gap is reserved between the inner side wall of the first gas float bearing 61 and the outer side wall of the shaft core 2, so that the shaft core 2 does not directly contact with the first gas float bearing 61 during work, the frictional resistance when the shaft core 2 rotates can be reduced, and the rotating speed of the shaft core 2 can be effectively improved.

[0038] An axial air passage 101 is arranged in the body 1, one end of the axial air passage 101 is in communication with the external compressed gas, and a plurality of groups of first radial holes 612 are arranged on the first gas float bearing 61, each group of first radial holes 612 is circumferentially distributed, and the two ends of the first radial hole 612 are respectively in communication with the axial air passage 101 and the first gap.

[0039] During work, the compressed gas flows into the axial air passage 101, then flows into the first radial hole 612, and then blows into the first gap; because the plurality of first radial holes 612 are circumferentially distributed, the compressed gas can be blown into the first gap on the outer side of the shaft core 2, and the compressed gas blown into the first gap can form a lubricating gas film with certain bearing capacity and rigidity on the outer side of the shaft core 2. At the same time, because the air in the first gap is flowing, the flowing gas can carry away the heat generated by the rotation of the shaft core 2, so that the stable rotation of the shaft core 2 can be ensured.

[0040] In order to make the compressed gas flow uniformly into each first radial hole 612, in the embodiment, a first annular groove 614 is arranged on the outer side wall of the first gas float bearing 61 at a position corresponding to the first radial hole 612, and the first annular groove 614 is respectively in communication with the first radial hole 612 and the axial air passage 101. During work, the compressed gas flows into the first annular groove 614 through the axial air passage 101, and then uniformly flows into each first radial hole 612, so that the gas pressure flowing into each first radial hole 612 is the same, thereby ensuring that a relatively stable gas film layer is formed in the first gap, and the stability of the rotation of the shaft core 2 is further improved.

[0041] Referring to Figure 2 As shown in FIG. 1, the energy transmission assembly 4 comprises a wireless power receiving module 41 and a wireless power supply module 42 which are arranged radially and spaced apart along the shaft core 2, the wireless power receiving module 41 is fixed to the outer side wall of the shaft core 2, and the outer diameter of the wireless power receiving module 41 is smaller than the inner diameter of the first gas float bearing 61. One end side wall of the wireless power supply module 42 is attached to the side wall opposite to the first gas float bearing 61, the other end side wall of the wireless power supply module 42 is attached to the positioning convex part 102 of the inner wall of the body 1, and is connected with the inner wall of the body 1, thereby realizing reliable positioning of the wireless power receiving module 41 and the wireless power supply module 42, and ensuring the reliability of the installation cooperation of the two.

[0042] A channel is also formed between the wireless power receiving module 41 and the wireless power supply module 42, which corresponds to the position of the first gap and is connected thereto. The compressed gas entering the first gap can also enter the channel, thereby achieving cooling of the energy transmission assembly 4.

[0043] In this embodiment, the wireless power supply module 42 is connected to an external ultrasonic power supply during operation. The wireless power supply module 42 and the wireless power receiving module 41 are gap-connected, achieving wireless energy transmission, thereby achieving ultrasonic machining of the air-floating motorized spindle. The wireless power supply module 42 and the wireless power receiving module 41 are both modularly designed, facilitating installation and maintenance. They are arranged along the radial direction of the shaft core 2. In the case of retaining a large amount of electrical power transmission, interference with the first air-floating bearing 61 and the driving assembly 3 is avoided, enabling high-precision assembly of the motorized spindle unit, thereby ensuring high rotational precision of the motorized spindle unit.

[0044] The first air-floating assembly 6 further comprises a thrust bearing 62, and the outer periphery of the shaft core 2 extends radially to form a limiting protrusion 21. The thrust bearing 62 is sleeved on the outer periphery of the shaft core 2. The thrust bearing 62 and the first air-floating bearing 61 are respectively arranged on the two sides opposite to the limiting protrusion 21, and a second gap and a third gap are respectively reserved between the thrust bearing 62 and the side wall of the limiting protrusion 21. The axial position of the shaft core 2 is limited by the thrust bearing 62, thereby preventing the shaft core 2 from moving axially during rotation.

[0045] The first air-floating bearing 61 is further provided with a first axial hole 613, which is in communication with all the first radial holes 612. During operation, the compressed gas flowing into the first annular groove 614 from the axial air channel 101 then flows into the first axial hole 613, and finally blows into the third gap. Since the first axial hole 613 is circumferentially distributed, the compressed gas blown into the third gap forms a lubricating gas film with certain bearing capacity and stiffness in the third gap, thereby supporting the shaft core 2 and preventing it from deviating away from the end cover 7.

[0046] Specifically, as shown in Figure 1 , 2 One end of the body 1 is provided with an end cover 7. One end of the shaft core 2, on which the tool shank 5 is arranged, penetrates the end cover 7 and extends out of the end face of the body 1. One end of the thrust bearing 62 is sealingly connected to the end cover 7. A plurality of second axial holes 621 are circumferentially arranged on the thrust bearing 62, and the second axial holes 621 are respectively in communication with the axial air channel 101 and the second gap. During operation, the compressed gas flows into the second axial holes 621 through the axial air channel 101, and then blows into the second gap. Since the second axial holes 621 are circumferentially distributed, the compressed gas blown into the second gap forms a lubricating gas film with certain bearing capacity and stiffness in the second gap, thereby supporting the shaft core 2 and preventing it from deviating towards the end cover 9.

[0047] Similarly, the connecting end surface of the thrust bearing 62 is provided with a second annular groove 622, which is arranged at the corresponding position of the second axial hole 621, so that each second axial hole 621 is in communication with the second annular groove 622 respectively, and the second annular groove 622 is also in communication with the axial air channel 101, so that the compressed gas can flow uniformly into each second axial hole 621, and the gas pressure flowing into each second axial hole 621 is the same, thereby ensuring the formation of a relatively uniform gas film layer in the second gap, further improving the stability of the rotation of the shaft core 2.

[0048] By arranging the second gap and the third gap, the left and right sides of the shaft core 2 can form a supporting gas film during work, thereby preventing the shaft core 2 from moving axially; and the non-contact cooperation relationship can improve the rotation speed of the shaft core 2, thereby reducing the grinding force and improving the machining precision.

[0049] In this embodiment, a damping plug 8 is arranged in each of the first radial hole 612, the first axial hole 613 and the second axial hole 621. By arranging the damping plug 8, the air flow rate flowing into the first gap, the second gap and the third gap can be controlled, and the gas pressure flowing in is ensured to be the same, thereby further improving the stability of the rotation of the shaft core 2. During work, the compressed gas flows into the first gap, the second gap and the third gap at the same time, thereby limiting the shaft core 2 in the axial and radial directions at the same time, ensuring that the shaft core 2 can rotate at high speed in the body 1, and improving the machining precision.

[0050] A spacing plate 11 is further arranged between the opposite side walls of the first gas bearing 61 and the thrust bearing 62, which is sleeved on the outer periphery of the limiting protrusion 21, thereby improving the stability of the overall structure installation. The spacing plate 11 is provided with air holes, which are respectively in communication with the axial air channel 101 and the second annular groove 622, thereby ensuring that the compressed gas in the axial air channel 101 can reliably enter the second annular groove 622, and then enter the second axial hole 621, and ensuring the formation of a relatively uniform gas film layer in the second gap.

[0051] In order to improve the stability of the rotational motion of the shaft core 2, a second gas floating assembly is arranged on the outer periphery of the end portion of the shaft core 2 away from the shank 5, which comprises a second gas bearing 12 and a gas floating bushing 13. The outer side wall of the second gas bearing 12 is sealingly connected with the inner side wall and the side wall of the body 1 respectively. The gas floating bushing 13 is arranged between the second gas bearing 12 and the shaft core 2, the inner side wall of the gas floating bushing 13 is fixedly connected with the outer side wall of the shaft core 2, and the fourth gap is formed between the gas floating bushing 13 and the second gas bearing 12. The second gas bearing 12 is provided with a third axial hole 121 and a plurality of second radial holes 122, the third axial hole 122 is in communication with the axial air channel 101; each group of second radial holes 122 is circumferentially distributed, and all the second radial holes 122 are in communication with the axial air channel 101 and the fourth gap.

[0052] Similarly, the second radial hole 121 is also provided with a damping plug 8, and working compressed gas flows into the axial air channel 101 through the third axial hole 121, and then flows into the second radial hole 122 and is blown into the fourth gap, since the second radial hole 122 is circumferentially distributed, the compressed gas blown into the fourth gap forms a lubricating gas film with certain carrying capacity and rigidity in the fourth gap, which further supports the shaft core 2 and prevents the shaft core 2 from deviating in the rotating motion.

[0053] The main shaft unit further comprises a tool changing assembly for tool changing operation of the tool shank 5. The tool changing assembly comprises a pull claw 14, a pull rod 15 and a tool changing driving unit (not shown in the figure), one end of the pull rod 15 is detachably connected with the tool changing driving unit, the other end of the pull rod 15 extends into the shaft core 2 and is detachably connected with the tool shank 5 through the pull claw 14. The pull claw 15 is used for clamping the tool shank 5, and the tool changing driving unit is used for driving the pull rod 15 to install and dismount the tool shank 5, thereby facilitating the replacement of the tool shank 5.

[0054] The pull rod 15 is sleeved with an elastic element 16, and the two ends of the elastic element 16 are connected with the pull rod 15 and the shaft core 2 respectively. When tool changing is needed, the tool changing driving unit pushes the pull rod 15 to slide, which stretches the spring 18, and the pull claw 14 is disengaged from the positioning groove on the tool shank 5, thereby facilitating the replacement of the tool shank 5; after the tool is replaced, the tool changing driving unit pushes the pull rod 15 to slide reversely, and the spring 18 is reset to drive the pull rod 15 and the pull claw 14 to move, so that the pull claw 14 is re-engaged with the positioning groove on the tool shank 5, that is, the tool replacement process is completed.

[0055] The ultrasonic air floatation electric main shaft unit can shorten the distance between the energy transmission assembly 4 and the transducer, avoid machining a long linear hole on the shaft core 2, and improve the structural rigidity and dynamic balance performance of the shaft core 2.

[0056] The above embodiment is a preferred implementation manner of the utility model, but the implementation manner of the utility model is not limited by the above embodiment, and any change, modification, replacement, combination and simplification made without departing from the spirit and principle of the utility model should be an equivalent replacement manner and should be included in the protection range of the utility model.

Claims

1. An ultrasonic gas float motorized spindle unit characterized by: The utility model provides a kind of tool holder, including body, shaft core arranged in body, drive assembly, energy transmission assembly and first gas bearing assembly are further arranged in the body and located the periphery of the shaft core, the end of the shaft core is respectively provided with tool holder and transducer, the drive assembly is used to drive the shaft core to carry out rotational motion in body; The first gas bearing assembly corresponds to the position of the tool holder, and is used to form a gas film around the shaft core;The energy transmission assembly is arranged between the drive assembly and the first gas bearing assembly, and the energy transmission assembly is connected with the transducer.

2. The ultrasonic gas-flush electric spindle unit according to claim 1, characterized in that: The drive assembly includes a motor stator and a motor rotor, and the motor rotor is sleeved on the outer periphery of the shaft core;The motor stator is arranged on the side of the motor rotor away from the shaft core, and a cooling jacket is arranged between the outer side wall of the motor stator and the inner side wall of the body.

3. The ultrasonic gas-flush motor spindle unit of claim 1, wherein: The first gas bearing assembly includes a first gas bearing, which is connected with the body and sleeved on the outer periphery of the shaft core, and a first gap is reserved between the first gas bearing and the shaft core. An axial gas passage for introducing compressed gas is provided on the body, and a plurality of first radial holes are provided on the first gas bearing, which are respectively communicated with the first gap and the axial gas passage.

4. The ultrasonic gas-flush motor spindle unit according to claim 3, characterized in that: The energy transmission assembly includes a wireless power receiving module and a wireless power supply module arranged radially along the shaft core, and the wireless power receiving module is connected with the shaft core;A channel is formed between the wireless power supply module and the wireless power receiving module, and the channel corresponds to and communicates with the position of the first gap.

5. The ultrasonic gas-flush motor spindle unit according to claim 4, characterized in that: The outer diameter of the wireless power receiving module is smaller than the inner diameter of the first gas bearing, and the two side walls of the wireless power supply module are respectively limited by the first gas bearing and the positioning convex part on the body, and are connected with the inner side wall of the body.

6. The ultrasonic gas-flush motor spindle unit according to any one of claims 1 to 5, characterized in that: A second gas bearing assembly is arranged on the outer periphery of the end of the shaft core away from the tool holder, and the second gas bearing assembly includes a second gas bearing and a gas bearing bushing, and the second gas bearing is connected with the body;The gas bearing bushing is arranged between the second gas bearing and the shaft core, and the gas bearing bushing is connected with the shaft core;The second gas bearing is used to form a gas film around the gas bearing bushing.

7. The ultrasonic gas-flush motor spindle unit of claim 3, wherein: The first gas bearing assembly further includes a thrust bearing sleeved on the outer periphery of the shaft core, and the outer periphery of the shaft core extends radially to form a limiting convex part;The thrust bearing and the first gas bearing are arranged on the two sides opposite to the limiting convex part, and a second gap and a third gap are respectively reserved between the side walls of the limiting convex part.

8. The ultrasonic gas-flush motor spindle unit according to claim 7, characterized in that: The first gas bearing further includes a first axial hole communicated with the first radial hole and the third gap, and a plurality of second axial holes are further provided on the thrust bearing, which are respectively communicated with the axial gas passage and the second gap.

9. The ultrasonic gas-flush motor spindle unit of claim 7, wherein: A spacing plate is further arranged between the side walls opposite to the first gas bearing and the thrust bearing, and the spacing plate is sleeved on the outer periphery of the limiting convex part.

10. The ultrasonic gas-flush motor spindle unit of claim 1, wherein: The utility model further includes a tool changing assembly for clamping and tool changing operation of the tool holder.

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