High-speed motorized spindle structure

Abstract

The application relates to the technical field of electric spindles, in particular to a high-speed electric spindle structure which comprises a mandrel, a shell, a front bearing, a rear bearing, a front gas seal assembly and a rear gas seal assembly, the front gas seal assembly comprises a labyrinth nut screwed on the mandrel and an end cover fixed to the end of the shell, and a gas curtain channel and a labyrinth channel are formed in communication between the two; an air inlet hole on the side wall of the shell is communicated with the gas curtain channel through a first air duct in the end cover; a radial gap is reserved between a dust cover and the front end face of the labyrinth nut, an axial gap is reserved between the outer side wall of the dust cover and the inner hole wall of the end cover, the radial gap is communicated with the axial gap; a second air duct in the labyrinth nut guides the airflow in the labyrinth channel to the radial gap, and the airflow in the gas curtain channel and the airflow in the labyrinth channel converge in the axial gap to jointly spray to form an annular gas curtain. The airflow is guided from the end of the labyrinth channel to the radial gap through the second air duct and is finally sprayed from the axial gap, so that the head-on phenomenon is effectively avoided, and the service life of the front bearing is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric spindle, in particular to a high-speed electric spindle structure. BACKGROUND

[0002] As the core functional component of high-speed and high-precision numerical control machine tools, the electric spindle has the structural advantage of integrating the motor rotor and the spindle, can realize stable operation without transmission gap, has the ability of rapid speed-up and speed-down, and micron-level machining precision, and has been widely used in high-precision machining scenes such as aerospace parts, precision molds, and core parts of automobile engines. The sealing structure design of the front bearing chamber of the electric spindle directly determines the operation stability and service life of the electric spindle, and is a key technical link in the research and development of the electric spindle.

[0003] In the existing structure, the sealing scheme of the electric spindle is a structure combined with labyrinth sealing and air curtain sealing. Specifically, the electric spindle includes a mandrel rotating synchronously with the motor rotor, a fixed housing, bearings assembled in the inner hole of the housing, and front and rear sealing structures respectively arranged at both ends of the housing. The front and rear sealing structures are composed of lock nuts and end covers, and the air curtain channel and the labyrinth channel are formed between the lock nuts and the end covers. The air inlet channel in the end cover makes the high-pressure gas flow to the outlet of the air curtain channel to form an annular air curtain, thereby preventing external debris and cooling liquid from invading.

[0004] However, the high-pressure gas will inevitably be divided in the intersection area of the air curtain channel and the labyrinth channel. Only 60%-70% of the gas flow can be ejected from the end face along the designed path to form an effective air curtain, and the remaining 30%-40% of the gas flow will invade the inside of the electric spindle along the gap of the labyrinth channel. During the initial operation of the electric spindle, the oil mist lubrication system is in a continuous state of lubricating the internal bearings, so that the invading divided gas flow will collide with the oil mist gas flow delivered by the oil mist lubrication system at the inlet of the front bearing chamber, thereby blocking the normal delivery path of the oil mist, causing the oil mist to fail to accurately reach the contact area of the rolling body and the raceway of the bearing, and causing the front bearing to fail to form an effective lubricating film, thereby causing the temperature of the front bearing to rise rapidly. In the long-term operation process, the front bearing will have irreversible defects such as micro-pitting and raceway wear due to insufficient continuous lubrication, which shortens the service life of the bearing and seriously affects the overall operation precision and stability of the electric spindle. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a high-speed electric spindle structure that effectively solves the problems in the background art.

[0006] To achieve the above purpose, the technical scheme adopted by the present application is as follows: a high-speed electric spindle structure, comprising: a mandrel, a housing sleeved on the outer side of the mandrel, front and rear bearings assembled in the inner hole of the housing, and front and rear air seal assemblies respectively arranged at both ends of the housing, the front air seal assembly comprising:

[0007] A labyrinth nut is screwed on the mandrel;

[0008] An end cover is coaxially sleeved outside the labyrinth nut and fixed to the end of the shell, and the gas curtain passage and the labyrinth passage are formed between the two;

[0009] The side wall of the shell is provided with an air inlet hole penetrating in the axial direction, and the air inlet hole is communicated with the gas curtain passage through the first air passage in the end cover;

[0010] The front end surface of the labyrinth nut is provided with a dust cover, and a radial gap is reserved between the end surface outer edge area of the dust cover and the front end surface of the labyrinth nut, and an axial gap is reserved between the outer side wall of the dust cover and the inner hole wall of the end cover, and the radial gap is communicated with the axial gap;

[0011] The inside of the labyrinth nut is provided with a second air passage penetrating in the axial direction, and a plurality of second air passages are distributed along the circumference of the labyrinth nut, one end of the second air passage is communicated with the outlet end of the labyrinth passage, and the other end is communicated with the radial gap, which is used to guide the shunt airflow in the labyrinth passage to the radial gap, and the airflow in the gas curtain passage is gathered in the axial gap, and the ring-shaped gas curtain is formed by being sprayed out together.

[0012] Further, the opposite side walls of the labyrinth nut and the end cover are provided with protrusions;

[0013] The protrusions on the two opposite side walls are staggered with each other, and there is a gap between the surfaces of the adjacent two protrusions on different side walls, and all the gaps are communicated to form the labyrinth passage.

[0014] Further, a stepped groove is provided on the inner side wall of the end cover close to one end of the dust cover, and a gas ring is embedded in the stepped groove, and a plurality of radial through holes are distributed on the circumferential side wall of the gas ring;

[0015] The outer side wall of the gas ring is interference fit with the stepped groove of the end cover, and the inner hole wall of the gas ring and the outer wall of the labyrinth nut form the gas curtain passage;

[0016] A first ring groove is provided on the inner hole wall of the end cover corresponding to the outlet position of the first air passage, and the first ring groove is communicated with the gas curtain passage through a plurality of radial through holes.

[0017] Further, a first gas collecting ring groove is formed on the inner side wall of the gas ring in the circumferential direction, and the axial position of the first gas collecting ring groove corresponds to the gas outlet end of the radial through hole of the gas ring;

[0018] A first sawtooth groove is provided on the outer side wall of the labyrinth nut corresponding to the position of the first gas collecting ring groove in the circumferential direction.

[0019] Further, the outer side wall of the labyrinth nut is provided with a plurality of second sawtooth grooves at the entrance of the labyrinth channel.

[0020] Further, the outer diameter of the dust cover is greater than the outer diameter of the labyrinth nut.

[0021] The air curtain channel and the axial gap are in a stepped structure in the radial direction.

[0022] Further, the dust cover is provided with an annular boss on the end face outer edge facing the gas ring and in the axial direction towards the gas ring.

[0023] The annular boss separates the radial gap into a first gap, a second gap and a third gap which are sequentially communicated in the radial direction.

[0024] The outlet of the second air passage is communicated with the first gap, the outlet of the air curtain channel is communicated with the third gap, and the side wall of the third gap is inclinedly arranged away from the gas ring.

[0025] Further, a helical groove is arranged on the outer circumferential side wall of the dust cover in the axial direction.

[0026] Further, the first air passage is arranged to be inclined towards the axis of the mandrel in the internal airflow flow direction.

[0027] Further, the second air passage is arranged to be inclined away from the axis of the mandrel in the internal airflow flow direction.

[0028] And a plurality of second air passages are arranged in the labyrinth nut.

[0029] The beneficial effects of the present application are: the second air passage of the present application introduces the airflow of the labyrinth channel from the end of the labyrinth channel to the radial gap, and then sprays out through the axial gap, effectively avoiding the collision phenomenon of the shunt airflow and the oil mist airflow in the labyrinth channel, ensuring the service life of the front bearing, improving the running accuracy and stability of the motorized spindle; and the shunt airflow introduced by the second air passage converges with the main airflow of the air curtain channel in the axial gap, forming a double-layer superimposed air curtain, improving the pressure and continuity of the air curtain at the axial gap. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments described in the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0031] Figure 1A cross-sectional view of a high-speed motorized spindle structure in an embodiment of the present application;

[0032] Figure 2 A structure schematic view of a front gas seal assembly in a high-speed motorized spindle structure in an embodiment of the present application;

[0033] Figure 3 A first structure schematic view of a front gas seal assembly in an embodiment of the present application;

[0034] Figure 4 A layout schematic view of a first air passage in a front gas seal assembly containing an air ring in an embodiment of the present application;

[0035] Figure 5 A layout schematic view of a second air passage in a front gas seal assembly containing an air ring in an embodiment of the present application;

[0036] Figure 6 A structure schematic view of a radial gap in an embodiment of the present application.

[0037] Reference signs: 10, mandrel; 20, housing; 21, air inlet hole; 30, front gas seal assembly; 30a, air curtain passage; 30b, labyrinth passage; 30c, radial gap; 301c, first gap; 302c, second gap; 303c, third gap; 30d, axial gap; 31, labyrinth nut; 311, second air passage; 312, first sawtooth groove; 313, second sawtooth groove; 32, end cover; 321, first air passage; 322, first ring groove; 33, dust cover; 331, annular boss; 34, air ring; 341, radial through hole; 342, first air collection ring groove; 40, rear gas seal assembly. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments.

[0039] It should be noted that when an element is referred to as being "on" another element, it can be directly on the other element or there can be an intervening element. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements can be present. The terms "vertical", "horizontal", "left", "right", and the like as used herein are used for illustration only and are not intended to be limiting.

[0040] 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 invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0041] like Figures 1 to 6 The high-speed electric spindle structure shown includes: a spindle 10, a housing 20 sleeved on the outside of the spindle 10, a front bearing and a rear bearing assembled in the inner hole of the housing 20, and a front air seal assembly 30 and a rear air seal assembly 40 respectively disposed at both ends of the housing 20. The front air seal assembly 30 includes a labyrinth nut 31 and an end cap 32. The labyrinth nut 31 is screwed onto the spindle 10. The end cap 32 is coaxially sleeved on the outside of the labyrinth nut 31 and fixed to the end of the housing 20. The two form a connected air curtain channel 30a and a labyrinth channel 30b.

[0042] The housing 20 has an axially penetrating air inlet 21 on its side wall, which connects to the air curtain channel 30a via a first air passage 321 inside the end cap 32. The labyrinth nut 31 has a dust cover 33 on its front end face, with a radial gap 30c between the outer edge of the dust cover 33 and the front end face of the labyrinth nut 31. An axial gap 30d is reserved between the circumferential side wall of the dust cover 33 and the inner wall of the end cap 32. The radial gap 30c and the axial gap 30d are respectively... 0d is connected; the interior of the labyrinth nut 31 is provided with a second air passage 311 running through it along the axial direction. Multiple second air passages 311 are distributed along the circumference of the labyrinth nut 31. One end of the second air passage 311 is connected to the outlet end of the labyrinth channel 30b, and the other end is connected to the radial gap 30c. It is used to guide the split airflow in the labyrinth channel 30b to the radial gap 30c, and converge with the airflow guided by the second air passage 311 in the axial gap 30d, and spray out together to form an annular air curtain. It should be noted that in this invention, the air inlet 21 and the first air passage 321 are configured in a one-to-one correspondence. To prevent gas leakage, a sealing ring is provided at the docking position of the air inlet 21 and the first air passage 321. Multiple air inlets 21 can be provided. During the operation of the electric spindle, one or multiple air inlets 21 can be opened to provide air source for the front air seal assembly 30 according to the usage requirements of the electric spindle machining process. In addition, the rear air seal assembly 40 has a similar structure to the front air seal assembly 30, both of which adopt a combination of labyrinth structure and air curtain channel 30a. The rear air seal assembly 40 and the front air seal assembly 30 share a single air inlet 21 for air supply.

[0043] The compressed air generated by the external air compressor enters the first air passage 321 of the end cover 32 through the air inlet hole 21 of the shell 20, and then flows into the air curtain channel 30a, the main flow is directly pushed into the axial gap 30d along the air curtain channel 30a, and the branch flow enters the labyrinth channel 30b, and when reaching the end of the labyrinth channel 30b, the remaining labyrinth teeth between the labyrinth channel 30b and the bearing chamber form a reverse resistance, so that the air flow preferentially flows to the second air passage 311, and after being axially transported along the second air passage 311 to the radial gap 30c, the air flow flows from the radial gap 30c to the axial gap 30d under the action of air pressure difference, and converges with the axial flow of the air curtain channel 30a in the axial gap 30d, and is finally sprayed along the axial direction to form an annular air curtain and sprayed from the axial gap 30d to the outside of the motorized spindle.

[0044] The second air passage 311 of the present application can effectively avoid the collision phenomenon of the branch flow and the oil mist flow, ensure the service life of the front bearing, and improve the operation accuracy and stability of the motorized spindle; and the branch flow introduced by the second air passage 311 can supplement the air curtain flow, and converge with the main flow of the air curtain channel 30a in the axial gap 30d, so as to form a double-layer superimposed air curtain and improve the pressure and continuity of the air curtain at the axial gap 30d.

[0045] In the present scheme, the protruding parts are arranged on the opposite side walls of the labyrinth nut 31 and the end cover 32; the protruding parts on the two opposite side walls are staggered with each other, and there are gaps between the surfaces of the adjacent two protruding parts on different side walls, and all the gaps are connected to form the labyrinth channel 30b.

[0046] When the high-speed motorized spindle stops working, the staggered arrangement of the protruding parts forms a zigzag labyrinth channel 30b, so that the flow path of the air flow becomes longer, a throttling effect is generated, the air outlet resistance is increased, and then the impurities such as cutting fluid and metal powder from the outside are prevented from entering the inside of the motorized spindle, so as to protect the cleanliness of the inside of the motorized spindle and help to prolong the service life of the precision bearings and other components of the motorized spindle, and when the compressed gas is introduced into the air curtain channel 30a, the gas flow in the labyrinth channel 30b is effectively reduced, and the pressure of the formed air curtain meets the requirements.

[0047] In the preferred embodiment of the present application, a stepped groove is arranged on the inner side wall of the end cover 32 near one end of the dustproof cover 33, a gas ring 34 is embedded in the stepped groove, a plurality of radial through holes 341 are distributed on the circumferential side wall of the gas ring 34, the outer side wall of the gas ring 34 is in interference fit with the stepped groove of the end cover 32, the gap between the inner hole wall of the gas ring 34 and the outer wall of the labyrinth nut 31 constitutes the air curtain channel 30a, a first ring groove 322 is arranged on the inner hole wall of the end cover 32 and corresponds to the outlet position of the first air passage 321, and the first ring groove 322 is communicated with the air curtain channel 30a through the plurality of radial through holes 341.

[0048] The first ring groove 322 is formed in the side wall of the hole in the end cover 32. When the gas enters the first ring groove 322, the compressed gas delivered by the first gas channel 321 can diffuse in the circumferential direction of the ring groove, eliminating the problem of local airflow concentration caused by single gas channel gas supply. The radial through holes 341 are uniformly distributed on the circumferential side wall of the gas ring 34, and are arranged at an interval of 60°-90° in the circumferential direction, and the axial position of the radial through holes 341 is precisely aligned with the first ring groove 322. The radial through holes 341 can synchronously guide the uniformly distributed gas in the first ring groove 322 into the gas curtain passage 30a, ensuring that the gas flow uniformly acts on the axial gap 30d, and finally the sprayed annular gas curtain has no breakage and no local weak area, thereby improving the blocking efficiency of external debris and cooling liquid. In addition, the gas ring 34 is fixed in the hole of the end cover 32 by interference fit. When the gap of the gas curtain passage 30a formed by the inner diameter of the gas ring 34 and the outer wall of the labyrinth nut 31 is out of tolerance, only the gas ring 34 with different wall thickness needs to be replaced, thereby reducing the maintenance cost.

[0049] In order to ensure the continuity of the gas curtain, a first gas collecting ring groove 342 is formed in the inner side wall of the gas ring 34 in the circumferential direction. The axial position of the first gas collecting ring groove 342 corresponds to the gas outlet end of the radial through hole 341 of the gas ring 34. The first gas collecting ring groove 342 is an annular groove formed in the circumferential direction of the inner side wall of the gas ring 34, and the axial position of the first gas collecting ring groove 342 is completely aligned with the gas outlet end of the radial through hole 341. The gas flow sprayed by the radial through hole 341 will first enter the first gas collecting ring groove 342 for buffering and diffusion, and then be uniformly distributed to the whole gas curtain passage 30a along the first gas collecting ring groove 342 in the circumferential direction, thereby ensuring that the gas flow of the gas curtain has no local weak area. The outer side wall of the labyrinth nut 31 is provided with a first sawtooth groove 312 at a position corresponding to the first gas collecting ring groove 342 in the circumferential direction.

[0050] Specifically, the opening end width of the first sawtooth groove 312 is greater than the width of the first gas collecting ring groove 342, which can better converge the gas flow entering the first gas collecting ring groove 342. The first sawtooth groove 312 has an obtuse triangle structure, and the inclination angle of the inclined side wall close to the gas curtain passage 30a is smaller than the inclination angle of the inclined side wall close to the labyrinth passage 30b. During rotation, the side wall with small inclination angle guides the gas flow into the gas curtain passage 30a, and the side wall with large inclination angle extrudes the gas in the sawtooth groove towards the gas curtain passage 30a, thereby reducing the gas diversion to the inside of the labyrinth passage 30b.

[0051] In the preferred structure, a plurality of second sawtooth grooves 313 are arranged on the outer side wall of the labyrinth nut 31 at the inlet of the labyrinth passage 30b. The second sawtooth groove 313 has a right triangle structure, one side wall of which is perpendicular to the axial direction of the shaft 10, and the other side wall is inclined to the outlet of the gas curtain passage 30a. During the rotation of the shaft 10 driving the labyrinth nut 31, the vertical side wall has a certain blocking effect on the entering gas flow, and the inclined side wall can push the gas in the second sawtooth groove 313 towards the end face.

[0052] In the present application, the dust cover 33 is arranged at the front end surface of the labyrinth nut 31, and the outer edge of the dust cover 33 extends in the radial direction to form an axial gap 30d with the stepped groove where the gas ring 34 is arranged. At this time, the outer diameter of the dust cover 33 is greater than the outer diameter of the labyrinth nut 31, and the gas curtain passage 30a and the axial gap 30d form a stepped structure in the radial direction, thereby forming a radial height difference barrier to prevent external impurities from entering the gas curtain passage 30a, and further ensuring the cleanliness inside the gas curtain passage 30a.

[0053] In a further preferred structure, the end surface of the dust cover 33 facing the gas ring 34 is provided with an annular boss 331 arranged in the axial direction towards the gas ring 34, and the annular boss 331 divides the radial gap 30c into a first gap 301c, a second gap 302c and a third gap 303c which are sequentially connected in the radial direction; the outlet of the second air channel 311 is connected to the first gap 301c, and the outlet of the gas curtain passage 30a is connected to the third gap 303c, and the side wall of the third gap 303c is arranged to be inclined away from the gas ring 34.

[0054] Specifically, the inner side wall of the dust cover 33 forms the first gap 301c with the front end surface of the labyrinth nut 31, the axial height section of the annular boss 331 forms the second gap 302c, and the side wall of the annular boss 331 forms the third gap 303c with the side wall of the gas ring 34; the airflow of the second air channel 311 first enters the first gap 301c, is then rectified through the narrow passage of the second gap 302c, and then enters the third gap 303c to converge with the airflow of the gas curtain passage 30a, thereby forming pressure superposition in the third gap 303c, and the side wall of the dust cover 33 located in the third gap 303c is inclined towards the axial gap 30d, and cooperates with the side wall of the gas ring 34 to form a conical ring groove, thereby adjusting the airflow direction and pressure of the airflow inside the third gap 303c, effectively reducing the turbulence intensity, and ensuring that the converged airflow can flow stably to the axial gap 30d.

[0055] As a preferred embodiment of the above, a helical groove is arranged on the outer circumferential side wall of the dust cover 33 in the axial direction; the axial length of the helical groove completely matches the axial width of the axial gap 30d, so that the helical groove completely covers the radially corresponding area of the axial gap 30d; when the dust cover 33 rotates synchronously with the mandrel 10 and the labyrinth nut 31, the helical groove applies a driving force to the airflow in the axial direction away from the motorized spindle, so as to promote the airflow to flow at high speed in the axial direction away from the motorized spindle, and further accelerate the gas curtain airflow converged in the third gap 303c to be sprayed out of the axial gap 30d, so as to strengthen the blocking effect of the gas curtain on external impurities.

[0056] In the preferred structure of the present application, the first air passage 321 is arranged to be inclined towards the axis of the mandrel 10 along the internal airflow direction. Compressed gas enters the air inlet hole 21 from the external air source and is delivered by the inclined first air passage 321 for airflow targeting, reducing the turning impact and pressure loss of the gas in the air passage, so that the compressed gas can reach the air curtain generating area in a shorter path, ensuring the stability of the initial pressure of the air curtain.

[0057] As a preferred solution, the second air passage 311 is arranged to be inclined away from the axis of the mandrel 10 along the internal airflow direction; and a plurality of second air passages 311 are arranged in the labyrinth nut 31, the second air passages 311 are used to guide the airflow in the labyrinth passage 30b to the radial gap 30c, and finally discharge the airflow outside the main shaft; a tapered gas collection chamber is arranged at the inlet end of the second air passage 311, and a confluence chamber is arranged at the inlet of the labyrinth passage 30b corresponding to the second air passage 311, the confluence chamber is connected to the tapered gas collection chamber; the flow cross-sectional area of the second air passage 311 is larger than the flow cross-sectional area of the end of the labyrinth passage 30b, so that the gas in the labyrinth passage 30b can smoothly enter the second air passage 311, and the plurality of second air passages 311 are arranged to be inclined in the opposite direction of the rotation direction of the mandrel 10, under the action of the centrifugal force generated by the high-speed rotation of the mandrel 10, the second air passages 311 arranged to be inclined form a superposition effect, driving the airflow to flow quickly along the inclined direction of the second air passage 311 to the radial outside away from the mandrel 10 without reverse resistance, greatly improving the airflow velocity and discharge efficiency.

[0058] Those skilled in the art should understand that the present application is not limited to the above-mentioned embodiments, and the above-mentioned embodiments and descriptions in the specification are only to illustrate the principles of the present application, and various changes and improvements can be made without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A high-speed motorized spindle structure, comprising a mandrel, a housing sleeved outside the mandrel, a front bearing and a rear bearing assembled in the inner hole of the housing, and a front gas seal assembly and a rear gas seal assembly respectively arranged at the two end portions of the housing, characterized in that, The front air seal assembly comprises: A labyrinth nut is screwed on the mandrel; An end cover is coaxially sleeved outside the labyrinth nut and fixed to the end of the shell, and the air curtain passage and the labyrinth passage are in communication between the two; Wherein, the side wall of the shell is provided with an air inlet hole along the axial direction, and the air inlet hole is communicated with the air curtain passage through the first air passage in the end cover; The front end surface of the labyrinth nut is provided with a dust cover, and a radial gap is reserved between the end surface outer edge of the dust cover and the front end surface of the labyrinth nut, and an axial gap is reserved between the circumferential side wall of the dust cover and the inner hole wall of the end cover, and the radial gap and the axial gap are communicated; The inside of the labyrinth nut is provided with a second air passage along the axial direction, one end of the second air passage is communicated with the end of the labyrinth passage, the other end is communicated with the radial gap, and the shunt airflow in the labyrinth passage is guided to the radial gap, and the airflow in the air curtain passage is gathered in the axial gap, and the ring-shaped air curtain is formed by being sprayed out together; A step groove is provided on the inner side wall of the end cover close to one end of the dust cover, and an air ring is embedded in the step groove, and a plurality of radial through holes are distributed on the circumferential side wall of the air ring; The outer side wall of the air ring is interference fit with the step groove of the end cover, and the inner hole wall between the outer wall of the labyrinth nut forms the air curtain passage; The inner hole wall of the end cover is provided with a first ring groove corresponding to the outlet position of the first air passage, and the first ring groove is communicated with the air curtain passage through a plurality of radial through holes; The outer diameter of the dust cover is greater than the outer diameter of the labyrinth nut; The air curtain passage and the axial gap are in a stepped structure in the radial direction; The end surface outer edge of the dust cover facing the air ring is provided with an annular boss in the axial direction towards the air ring; The annular boss separates the radial gap into a first gap, a second gap and a third gap which are communicated in turn in the radial direction; Wherein, the outlet of the second air passage is communicated with the first gap, the outlet of the air curtain passage is communicated with the third gap, and the side wall of the third gap is inclined towards the direction away from the air ring; A spiral groove is provided on the outer circumferential side wall of the dust cover; The first air passage is inclined towards the axis direction close to the mandrel along the internal airflow flow direction; The second air passage is inclined towards the axis direction away from the mandrel along the internal airflow flow direction; And a plurality of second air passages are provided in the labyrinth nut.

2. High-speed electrospindle structure according to claim 1, characterized in that, The opposite side walls of the labyrinth nut and the end cover are provided with protrusions; The protrusions on the two opposite side walls are staggered with each other, and there is a gap between the surfaces of adjacent two protrusions on different side walls, and all the gaps are communicated to form the labyrinth passage.

3. The high-speed electrospindle structure according to claim 1, characterized in that A first air collecting ring groove is formed on the inner side wall of the air ring in the circumferential direction, and the axial position of the first air collecting ring groove corresponds to the radial through hole gas outlet end of the air ring; A first sawtooth groove is provided on the outer side wall of the labyrinth nut corresponding to the position of the first air collecting ring groove.

4. The high-speed electrospindle structure according to claim 1, characterized in that, A plurality of second sawtooth grooves are provided on the outer side wall of the labyrinth nut at the inlet of the labyrinth passage.

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