Motorized spindle supported by water lubrication dynamic pressure bearing and gas static pressure bearing in conversion mode

Abstract

The invention provides an electric spindle supported by water lubrication dynamic pressure and gas static pressure bearings in a switching mode. The electric spindle comprises a shell, a spindle body, a front water lubrication dynamic pressure radial bearing, a rear water lubrication dynamic pressure radial bearing, a water lubrication dynamic pressure thrust bearing, a front gas static pressure conical bearing, a rear gas static pressure conical bearing, a high-speed permanent magnet synchronous motor, a front hydraulic adjusting device and a rear hydraulic adjusting device. Wherein an inner sleeve and an outer sleeve are arranged on the outer sides of the front gas static pressure conical bearing and the rear gas static pressure conical bearing, and balls are arranged between the inner sleeve and the outer sleeve. In the working process of the motorized spindle, the pressure of liquid plastic in the front piston liquid plastic extrusion cylinder and the rear piston liquid plastic extrusion cylinder is adjusted through the front hydraulic adjusting device and the rear hydraulic adjusting device, the axial position of a gas bearing bush is changed, then the working clearance of the front gas static pressure conical bearing and the rear gas static pressure conical bearing is adjusted and controlled, and mutual conversion of a water lubrication dynamic pressure bearing support and a gas static pressure bearing support of the spindle is completed. According to the electric spindle, high-speed precision machining with the large cutting allowance can be achieved, ultra-high-speed ultra-precision machining with the small cutting allowance can also be achieved, then the machining capacity of the electric spindle is greatly improved, and the application range is widened.

Description

Technical Field

[0001] The invention relates to the technical field of precision machining machine tools, in particular to an electric spindle supported by a water-lubricated dynamic pressure and gas static pressure bearing conversion. Background Art

[0002] The electric spindle is the core functional component of high-speed precision machining machine tools, and its performance indicators often directly determine the working performance and grade of the machine tools. Gas bearing electric spindles use gas with extremely low viscosity as lubricant, and have extremely low friction loss. They have been widely used in ultra-high-speed and ultra-precision machine tools; but due to the compressibility of gas, their bearing capacity and support stiffness are relatively small. In comparison, water-lubricated hydrodynamic bearing electric spindles use water as lubricant, which has greater bearing capacity and stiffness, and are suitable for high-speed precision machine tools with large machining allowances. However, as the speed increases further, the water-lubricated hydrodynamic bearings heat up seriously, and the maximum operating speed of the electric spindle is subject to certain restrictions; in addition, friction and wear of the hydrodynamic bearings are inevitable during the start-up and shutdown stages, affecting the rotation accuracy of the electric spindle.

[0003] In actual engineering, a high-speed precision machining machine tool is often equipped with only one set of electric spindles, such as a gas bearing electric spindle and a water-lubricated bearing electric spindle, which limits the scope of application of the machine tool. In order to further improve the processing capacity of the machine tool and expand its scope of application, it is necessary to design an electric spindle with gas bearing and water-lubricated bearing conversion support. However, the working clearance of the gas bearing is significantly smaller than the working clearance of the water-lubricated bearing, which poses a new challenge to the design of the electric spindle with the above two types of bearing conversion support. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the present invention provides an electric spindle with water-lubricated dynamic pressure and gas static pressure bearing conversion support, aiming to realize the active switching of the spindle between water-lubricated dynamic pressure bearing support and gas static pressure bearing support, so that the electric spindle can not only complete high-speed precision machining with a large cutting allowance, but also complete ultra-high-speed ultra-precision machining with a small cutting allowance, thereby greatly improving its machining capacity and expanding its application scope.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] An electric spindle with a conversion support for a hydrostatic sliding bearing and a gas static pressure bearing, comprising a housing, a spindle, front and rear hydrostatic sliding radial bearings arranged inside the housing, a hydrostatic sliding thrust bearing arranged at the front end of the front hydrostatic sliding radial bearing, a high-speed permanent magnet synchronous motor arranged between the front and rear hydrostatic sliding radial bearings, a front gas static pressure tapered bearing arranged between the front hydrostatic sliding radial bearing and the high-speed permanent magnet synchronous motor, a rear gas static pressure tapered bearing arranged between the rear hydrostatic sliding radial bearing and the high-speed permanent magnet synchronous motor, front and rear hydraulic regulating devices arranged at the rear side of the housing, and front and rear end covers arranged on both sides of the housing; during the working process of the electric spindle, the axial positions of the bearing bushes of the front and rear gas static pressure tapered bearings are changed through the front and rear hydraulic regulating devices, so as to further regulate the working clearances of the front and rear gas static pressure tapered bearings, and realize the mutual conversion of the spindle supported by the hydrostatic sliding bearing and the gas static pressure bearing.

[0007] Further, the front hydrostatic sliding radial bearing includes a front hydrostatic sliding radial bearing bush and a front hydrostatic sliding radial bearing journal. Among them, a first water inlet ring groove is arranged in the middle of the front hydrostatic sliding radial bearing bush, and first and second pressure relief ring grooves are arranged on both sides; the rear hydrostatic sliding radial bearing includes a rear hydrostatic sliding radial bearing bush and a rear hydrostatic sliding radial bearing journal. Among them, a second water inlet ring groove is arranged in the middle of the rear hydrostatic sliding radial bearing bush, and a third pressure relief ring groove is arranged on the front side; herringbone grooves are arranged on the front and rear hydrostatic sliding radial bearing journals, and a drainage cavity is arranged on the rear end cover.

[0008] Further, the hydrostatic sliding thrust bearing includes a thrust disc and front and rear thrust pads. Among them, the front and rear thrust pads are arranged on both sides of the thrust disc and separated by an adjusting ring. Third and fourth water inlet ring grooves are respectively arranged on the working surfaces of the front and rear thrust pads. A fourth pressure relief ring groove is arranged on the inner hole of the front thrust pad, and a drainage hole is arranged on the adjusting ring; spiral grooves are arranged on the front and rear working surfaces of the thrust disc, and a gas sealing ring groove is arranged on the front end cover.

[0009] Further, the front gas static pressure tapered bearing includes a front gas bearing journal and a front gas bearing bush. A front gas bearing inner sleeve is sleeved outside the front gas bearing bush, and a front gas bearing outer sleeve is sleeved inside the housing; a plurality of front piston liquid plastic extrusion cylinders are arranged along the circumferential direction on one end face of the front gas bearing outer sleeve. A front piston is arranged in the front piston liquid plastic extrusion cylinder, and the front piston is fixedly connected with the front gas bearing inner sleeve through a push rod; a plurality of spring holes are arranged along the circumferential direction on one end face of the front gas bearing inner sleeve and on the housing. A front spring is arranged in the spring hole, and a first air inlet ring groove is arranged inside the front gas bearing inner sleeve.

[0010] Further, the rear aerostatic conical bearing includes a rear gas bearing journal and a rear gas bearing bush. A rear gas bearing inner sleeve is sleeved outside the rear gas bearing bush, and a rear gas bearing outer sleeve is sleeved inside the housing. A plurality of rear piston liquid-plastic extrusion cylinders are circumferentially arranged on one end face of the rear gas bearing outer sleeve. A rear piston is arranged in the rear piston liquid-plastic extrusion cylinder, and the rear piston is fixedly connected to the rear gas bearing inner sleeve through a push rod. A plurality of spring holes are circumferentially arranged on one end face of the rear gas bearing inner sleeve and on the housing. A rear spring is arranged in the spring hole. A second air inlet ring groove is arranged inside the rear gas bearing inner sleeve.

[0011] Further, a plurality of raceways are circumferentially arranged on the inner holes of the front and rear gas bearing outer sleeves. Ball bearings are arranged in the raceways for radial support and axial movement guidance of the front and rear gas bearing inner sleeves.

[0012] Further, the front and rear hydraulic regulating devices include adjusting screws, screw sleeves, plunger liquid-plastic extrusion cavities, plungers and liquid plastics. Front and rear liquid-plastic channels are arranged inside the housing, and the front and rear liquid-plastic channels are filled with liquid plastics.

[0013] Further, a main water inlet channel, a main air-water discharge channel, a main air inlet channel and a main exhaust channel are arranged on the housing. Among them, the main water inlet channel communicates with an external normal-pressure water supply device, and the main air inlet channel communicates with an external high-pressure air supply device. The first to fourth water inlet ring grooves are respectively connected to the main water inlet channel through the first to fourth water inlet channels to provide normal-pressure water for the front and rear water-lubricated hydrodynamic radial bearings and the water-lubricated hydrodynamic thrust bearings. The first to fourth pressure relief ring grooves, the drain cavity and the drain holes are respectively connected to the main air-water discharge channel through the first drain channel, the first to third air-water discharge channels, the second and third drain channels to discharge the lubricating media in the water-lubricated hydrodynamic bearings and the aerostatic bearings. The first to second air inlet ring grooves and the air seal ring groove are respectively connected to the main air inlet channel through the first to third air inlet channels to provide high-pressure gas for the aerostatic conical bearing and the axial seal.

[0014] During the operation of the electric spindle, the liquid plastic pressure in the front and rear piston liquid-plastic extrusion cylinders is regulated by the front and rear hydraulic regulating devices, so that the push rods fixedly connected to the front and rear pistons drive the inner sleeves of the front and rear gas bearings to move axially relative to the outer sleeves, changing the axial positions of the axial bearings of the front and rear gas bearings, and further adjusting the working clearances of the front and rear gas static pressure conical bearings; when the electric spindle is in the starting and stopping stages, the working clearances of the front and rear gas static pressure conical bearings are reduced, so that the gas static pressure bearings mainly play an auxiliary supporting role to eliminate the friction and wear of the water-lubricated sliding pressure bearings; when the electric spindle performs high-speed precision machining with a large machining allowance, the external water supply device is connected, and the spindle is supported by the water-lubricated sliding pressure bearings, and at the same time, the working clearances of the front and rear gas static pressure conical bearings are increased, so that the gas static pressure mainly plays an axial sealing role; when the electric spindle performs ultra-high-speed ultra-precision machining with a small machining allowance, the external water supply device is closed, the working clearances of the front and rear gas static pressure conical bearings are reduced, and the spindle is supported by the gas static pressure bearings.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] 1. By turning on and off the water supply condition and adjusting the clearance of the gas bearings, the present invention realizes the active conversion of the spindle support mode, that is, under the condition of a large cutting allowance, the spindle is supported by the water-lubricated sliding pressure bearings with large load-bearing capacity and high stiffness to complete the high-speed precision machining of the electric spindle; under the condition of a small cutting allowance, the spindle is supported by the gas static pressure bearings with small load-bearing capacity and low stiffness to complete the ultra-high-speed ultra-precision machining of the electric spindle.

[0017] 2. The present invention changes the axial position of the axial bearing of the gas static pressure conical bearing through the hydraulic regulating device, actively regulates the clearance of the gas static pressure conical bearing, and further realizes the axial sealing function of the gas static pressure spindle support and the water-lubricated sliding pressure radial bearing.

[0018] 3. The gas static pressure bearing in the present invention can play an auxiliary supporting role, avoiding the friction and wear of the water-lubricated sliding pressure bearing during the starting and stopping stages, and thus prolonging its service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic structural diagram of the vertical longitudinal section ([ Figure 2 section at B-B in

[0020] Figure 2 is Figure 1 the view from direction A in

[0021] Figure 3 is Figure 2 the schematic structural diagram of the section at C-C in

[0022] Figure 4 is Figure 2 the schematic structural diagram of the section at D-D in

[0023] Figure 5 is Figure 4 The partial enlarged view at position E in

[0024] Figure 6 the schematic diagram of the outer sleeve and piston structure of the gas bearing.

[0025] Figure 7 the schematic diagram of the inner sleeve structure of the gas bearing.

[0026] Figure 8 the schematic diagram of the spiral groove structure of the water-lubricated hydrodynamic thrust bearing: a) the spiral groove on the front working surface of the thrust plate; b) the spiral groove on the rear working surface of the thrust plate.

[0027] Description of the reference numerals in the drawings: 1 - housing, 101 - main water inlet channel, 102 - main air-water discharge channel, 103 to 104 - first to second water inlet channels, 105 to 107 - first to third air-water discharge channels, 108 - first drainage channel, 109 - third drainage channel, 110 - main air inlet channel, 111 - main exhaust channel, 112 to 113 - first to second air inlet channels, 114 to 115 - first to second exhaust channels, 116 - front liquid-plastic channel, 117 - rear liquid-plastic channel, 2 - main shaft, 3 - front water-lubricated sliding pressure radial bearing, 301 - bearing bush of the front water-lubricated sliding pressure radial bearing, 302 - journal of the front water-lubricated sliding pressure radial bearing, 303 - first water inlet ring groove, 304 to 305 - first to second pressure relief ring grooves, 306 - fourth water inlet channel, 4 - rear water-lubricated sliding pressure radial bearing, 401 - bearing bush of the rear water-lubricated sliding pressure radial bearing, 402 - journal of the rear water-lubricated sliding pressure radial bearing, 403 - second water inlet ring groove, 404 - third pressure relief ring groove, 5 - front gas static pressure conical bearing, 501 - journal of the front gas bearing, 502 - bearing bush of the front gas bearing, 503 - inner sleeve of the front gas bearing, 504 - outer sleeve of the front gas bearing, 505 - front piston, 506 - front piston liquid-plastic extrusion cylinder, 507 - front spring, 508 - first air inlet ring groove, 509 - orifice throttle, 510 - raceway, 511 - ball, 512 - screw, 513 - push rod, 514 - spring hole, 6 - rear gas static pressure conical bearing, 601 - journal of the rear gas bearing, 602 - bearing bush of the rear gas bearing, 603 - inner sleeve of the rear gas bearing, 604 - outer sleeve of the rear gas bearing, 605 - rear piston, 606 - rear piston liquid-plastic extrusion cylinder, 607 - rear spring, 608 - second air inlet ring groove, 7 - water-lubricated sliding pressure thrust bearing, 701 - thrust plate, 702 - front thrust pad, 703 - rear thrust pad, 704 - adjusting ring, 705 to 706 - third to fourth water inlet ring grooves, 707 - fourth pressure relief ring groove, 708 - drain hole, 8 - front hydraulic regulating device, 801 - screw sleeve, 802 - adjusting screw, 803 - plunger, 804 - plunger liquid-plastic extrusion cavity, 805 - liquid plastic, 9 - rear hydraulic regulating device, 10 - herringbone groove, 1001 - groove area, 1002 - platform area, 1003 - dam area, 1004 - spiral groove, 11 - high-speed permanent magnet synchronous motor, 1101 - motor stator, 1102 - motor rotor, 1103 - cooling water jacket, 12 - front end cover, 1201 - third water inlet channel, 1202 - third air inlet channel, 1203 - air sealing ring groove, 13 - rear end cover, 1301 - drainage cavity, 1302 - second drainage channel. Detailed implementation manners

[0028] The following will further elaborate on the present invention in conjunction with the attached Figures 1 to 8 drawings, but the present invention is not limited to the scope of the embodiments.

[0029] Refer to Figures 1 to 8 Figures 1 to 8 , an electric spindle with a conversion support for a water-lubricated sliding bearing and a gas static pressure bearing in this embodiment includes a housing 1, a main shaft 2, front and rear water-lubricated sliding radial bearings 3 and 4 arranged in the housing 1, a water-lubricated sliding thrust bearing 7 arranged at the front end of the front water-lubricated sliding radial bearing 3, a high-speed permanent magnet synchronous motor 11 arranged between the front and rear water-lubricated sliding radial bearings 3 and 4, a front gas static pressure conical bearing 5 arranged between the front water-lubricated sliding radial bearing 3 and the high-speed permanent magnet synchronous motor 11, a rear gas static pressure conical bearing 6 arranged between the rear water-lubricated sliding radial bearing 4 and the high-speed permanent magnet synchronous motor 11, front and rear hydraulic regulating devices 8 and 9 arranged at the rear side of the housing 1, and front and rear end covers 12 and 13 arranged on both sides of the housing 1. During the working process of the electric spindle, the working clearances of the front and rear gas static pressure conical bearings 5 and 6 are changed through the front and rear hydraulic regulating devices 8 and 9 to realize the mutual conversion of the main shaft supported by the water-lubricated sliding bearing and the gas static pressure bearing.

[0030] Refer to Figure 1 Figure 1 , the front water-lubricated sliding radial bearing 3 is composed of a front water-lubricated sliding radial bearing bush 301 and a front water-lubricated sliding radial bearing journal 302; wherein, a first water inlet ring groove 303 is arranged in the middle of the front water-lubricated sliding radial bearing bush 301, and first and second pressure relief ring grooves 304 and 305 are arranged on both the front and rear sides. The rear water-lubricated sliding radial bearing 4 is composed of a rear water-lubricated sliding radial bearing bush 401 and a rear water-lubricated sliding radial bearing journal 402; wherein, a second water inlet ring groove 403 is arranged in the middle of the rear water-lubricated sliding radial bearing bush 401, a third pressure relief ring groove 404 is arranged on the front side, and a drainage cavity 1301 is arranged on the rear end cover 13 at the rear side. Herringbone grooves 10 are arranged on the working surfaces of the front and rear water-lubricated sliding radial bearing journals 302 and 402, and the herringbone grooves 10 divide the working surfaces into a groove area 1001, a platform area 1002, and a dam area 1003.

[0031] Refer to Figure 1 and Figure 8 Figure 8 , the water-lubricated sliding thrust bearing 7 is composed of a thrust disc 701, and front and rear thrust pads 702 and 703; wherein, the thrust disc 701 is press-fitted on the main shaft 2, and the front and rear thrust pads 702 and 703 are arranged on both sides of the thrust disc 701 and separated by an adjusting ring 704. Third and fourth water inlet ring grooves 705 and 706 are respectively arranged on the working surfaces of the front and rear thrust pads 702 and 703, a fourth pressure relief ring groove 707 is arranged on the inner hole of the front thrust pad 702, a gas seal ring groove 1203 is arranged on the front end cover 12 at the front side, and a drainage hole 708 is arranged on the adjusting ring 704. Helical grooves 1004 are arranged on the front and rear working surfaces of the thrust disc 701, and the helical grooves 1004 divide the working surface of the thrust disc into a groove area 1001, a platform area 1002, and a dam area 1003.

[0032] Refer to Figure 3 , the front aerostatic conical bearing 5 is composed of a front gas bearing journal 501 and a front gas bearing bush 502, and the rear aerostatic conical bearing 6 is composed of a rear gas bearing journal 601 and a rear gas bearing bush 602; wherein, two rows of orifice restrictors 509 are axially arranged on the front and rear gas bearing bushes 502 and 602, and several are circumferentially arranged in each row. The outer sides of the front and rear gas bearing bushes 502 and 602 are respectively sleeved with front and rear gas bearing inner sleeves 503 and 603, and the inner sides of the housing 1 are sleeved with front and rear gas bearing outer sleeves 504 and 604; wherein, four raceways 510 are circumferentially arranged on the inner sides of the front and rear gas bearing outer sleeves 504 and 604, and balls 511 are arranged in the raceways 510. The front and rear gas bearing outer sleeves 504 and 604 are respectively used for radial support and axial guidance of the front and rear gas bearing inner sleeves 503 and 603.

[0033] Refer to Figures 4 to 7 , six front and rear piston hydroplastic extrusion cylinders 506 and 606 are respectively circumferentially arranged on one end faces of the front and rear gas bearing outer sleeves 504 and 604. Front and rear pistons 505 and 605 are respectively arranged in the front and rear piston hydroplastic extrusion cylinders 506 and 606. The push rods 513 in the front and rear pistons 505 and 605 are respectively connected to the front and rear gas bearing inner sleeves 503 and 603 through screws 512. Ten spring holes 514 are respectively circumferentially arranged on one end faces of the front and rear gas bearing inner sleeves 503 and 603 and the corresponding housing 1. Front and rear springs 507 and 607 are arranged in the spring holes 514; first and second air inlet annular grooves 508 and 608 are respectively arranged on the inner sides of the front and rear gas bearing inner sleeves 503 and 603.

[0034] Refer to Figure 4 and Figure 5, the front and rear hydraulic regulating devices 8 and 9 include a screw sleeve 801 arranged on the rear end cover 13, an adjusting screw 802 arranged in the screw sleeve 801, a plunger liquid-plastic extrusion cavity 804 arranged in the rear end cover 13, and a plunger 803 arranged in the plunger liquid-plastic extrusion cavity 804; wherein, one end face of the plunger 803 is in point contact with the ball at the end of the adjusting screw 802, the other end face of the plunger 803 abuts against the liquid level of the liquid plastic 805, and the outer cylindrical surface of the plunger 803 is matched with the plunger liquid-plastic extrusion cavity 804 and kept sealed. Front and rear liquid-plastic channels 116 and 117 are arranged in the housing 1, and the front and rear piston liquid-plastic extrusion cylinders 506 and 606 are respectively communicated with the plunger liquid-plastic extrusion cavities 804 in the front and rear hydraulic regulating devices 8 and 9 through the front and rear liquid-plastic channels 116 and 117, and are filled with liquid plastic 805. During the operation of the motorized spindle, the adjusting screws 802 in the front and rear hydraulic regulating devices 8 and 9 are adjusted to change the position of the plunger 803 in the plunger liquid-plastic extrusion cavity 804, and the pressure of the liquid plastic 805 in the front and rear piston liquid-plastic extrusion cylinders 506 and 606 is regulated, so that the push rods 513 in the front and rear pistons 505 and 605 push the front and rear gas bearing inner sleeves 503 and 603 to move axially relative to the front and rear gas bearing outer sleeves 504 and 604 respectively until the axial movement stops when the liquid pressure on the end faces of the front and rear pistons 505 and 605 is balanced with the elastic forces of the front and rear springs 507 and 607, and the axial positions of the front and rear gas bearing bearing bushes 502 and 602 are changed, thereby adjusting the working clearances of the front and rear gas static pressure conical bearings 5 and 6.

[0035] Refer to Figure 1, a water inlet main channel 101 and a gas-water discharge main channel 102 are provided on the housing 1; among them, the water inlet main channel 101 communicates with an external atmospheric pressure water supply device, and the gas-water discharge main channel 102 communicates with an external recovery and circulation device. The first and second water inlet annular grooves 303 and 403 are respectively connected to the water inlet main channel 101 through the first and second water inlet channels 103 and 104 to supply atmospheric pressure water to the front and rear water lubricated sliding pressure radial bearings 3 and 4; among them, the first water inlet channel 103 sequentially passes through the housing 1 and the front water lubricated sliding pressure radial bearing bush 301 from outside to inside, and the second water inlet channel 104 sequentially passes through the housing 1 and the rear water lubricated sliding pressure radial bearing bush 401 from outside to inside. The third water inlet annular groove 705 is connected to the water inlet main channel 101 through the third water inlet channel 1201, and the fourth water inlet annular groove 706 is sequentially connected to the water inlet main channel 101 through the fourth water inlet channel 306 and the first water inlet channel 103 to supply atmospheric pressure water to the front and rear thrust washers 702 and 703; among them, the third water inlet channel 1201 sequentially passes through the front end cover 12 and the front thrust washer 702 from front to back, and the fourth water inlet channel 306 sequentially passes through the front water lubricated sliding pressure radial bearing bush 301 and the rear thrust washer 703 from back to front. The first pressure relief annular groove 304 and the drainage cavity 1301 are respectively connected to the gas-water discharge main channel 102 through the first and second drainage channels 108 and 1302 to discharge part of the lubricating medium in the front and rear water lubricated sliding pressure radial bearings 3, 4 and the water lubricated sliding pressure thrust bearing 7; among them, the first drainage channel 108 sequentially passes through the front water lubricated sliding pressure radial bearing bush 301 and the housing 1 from inside to outside, and the second drainage channel 1302 is arranged in the rear end cover 13. The second and third pressure relief annular grooves 305 and 404 are respectively connected to the gas-water discharge main channel 102 through the first and second gas-water discharge channels 105 and 106 to discharge part of the lubricating medium in the front and rear water lubricated sliding pressure radial bearings 3, 4 and the front and rear gas static pressure conical bearings 5, 6; among them, the first gas-water discharge channel 105 sequentially passes through the front water lubricated sliding pressure radial bearing bush 301 and the housing 1 from inside to outside, and the second gas-water discharge channel 106 sequentially passes through the rear water lubricated sliding pressure radial bearing bush 401 and the housing 1 from inside to outside. The drain hole 708 is connected to the gas-water discharge main channel 102 through the third drainage channel 109 to discharge part of the lubricating medium in the water lubricated sliding pressure thrust bearing 7; among them, the third drainage channel 109 is arranged in the housing 1. The fourth pressure relief annular groove 707 is connected to the gas-water discharge main channel 102 through the third gas-water discharge channel 107 to discharge part of the lubricating medium and sealing gas in the water lubricated sliding pressure thrust bearing 7; among them, the third gas-water discharge channel 107 sequentially passes through the front thrust washer 702 and the housing 1 from inside to outside.

[0036] Refer to Figure 3, an air intake main channel 110 and an exhaust main channel 111 are provided on the housing 1; among them, the air intake main channel 110 communicates with an external high-pressure air supply device, and the exhaust main channel 111 communicates with the outside. The high-speed permanent magnet synchronous motor 11 is composed of a motor stator 1101 and a motor rotor 1102; among them, a cooling water jacket 1103 is sleeved outside the motor rotor 1102, and the cooling water jacket 1103 is sleeved inside the housing 1. The first and second air intake annular grooves 508 and 608 are respectively connected to the air intake main channel 110 through the first and second air intake channels 112 and 113 to provide high-pressure gas for the front and rear gas static pressure conical bearings 5 and 6; among them, the first air intake channel 112 sequentially passes through the housing 1, the front gas bearing outer sleeve 504 and the front gas bearing inner sleeve 503 from outside to inside, and the second air intake channel 113 sequentially passes through the housing 1, the rear gas bearing outer sleeve 604 and the rear gas bearing inner sleeve 603 from outside to inside. The air seal annular groove 1203 is connected to the air intake main channel 110 through the third air intake channel 1202 to provide sealing gas to prevent the lubricating medium in the water-lubricated hydrodynamic thrust bearing 7 from leaking to the outside; among them, the third air intake channel 1202 is arranged in the front end cover 12. The first and second exhaust channels 114 and 115 are connected to the exhaust main channel 111 to discharge part of the lubricating medium in the front and rear gas static pressure conical bearings 5 and 6, and the first and second exhaust channels 114 and 115 sequentially pass through the cooling water jacket 1103 and the housing 1 from inside to outside.

[0037] The working process of the motorized spindle is as follows:

[0038] 1. The motorized spindle is in the starting and stopping stage:

[0039] Adjust the front and rear hydraulic regulating devices 8 and 9 to change the working clearances of the front and rear gas static pressure conical bearings 5 and 6, so that the air static pressure mainly plays an auxiliary supporting role to overcome the self-weight of the spindle 2, thereby eliminating the friction and wear of the water-lubricated hydrodynamic bearing.

[0040] 2. The motorized spindle is in the normal working stage:

[0041] 1) When performing high-speed precision machining with a large margin, connect the external water supply device, adjust the front and rear hydraulic regulating devices 8 and 9 to change the working clearances of the front and rear gas static pressure conical bearings 5 and 6. At this time, the spindle 2 is mainly supported by the front and rear water-lubricated hydrodynamic bearings 3 and 4, and the air static pressure mainly plays the role of axial sealing of the lubricating medium of the water-lubricated hydrodynamic radial bearing;

[0042] 2) When performing ultra-high-speed and ultra-precision machining with a small margin, turn off the external water supply device, adjust the front and rear hydraulic regulating devices 8 and 9 to change the working clearances of the front and rear gas static pressure conical bearings 5 and 6. At this time, the spindle 2 is mainly supported by the front and rear gas static pressure conical bearings 5 and 6.

[0043] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, there are various modifications and variations to the present invention. Any modifications, equivalent replacements, improvements, etc. made within the basic spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. An electric spindle with a conversion support for hydrodynamic sliding pressure and aerostatic bearings, characterized in that: It includes a housing (1), a main shaft (2), front and rear water-lubricated sliding pressure radial bearings (3 and 4) arranged inside the housing (1), a water-lubricated sliding pressure thrust bearing (7) arranged at the front end of the front water-lubricated sliding pressure radial bearing (3), a high-speed permanent magnet synchronous motor (11) arranged between the front and rear water-lubricated sliding pressure radial bearings (3 and 4), a front gas static pressure tapered bearing (5) arranged between the front water-lubricated sliding pressure radial bearing (3) and the high-speed permanent magnet synchronous motor (11), a rear gas static pressure tapered bearing (6) arranged between the rear water-lubricated sliding pressure radial bearing (4) and the high-speed permanent magnet synchronous motor (11), front and rear hydraulic regulating devices (8 and 9) arranged at the rear side of the housing (1), and front and rear end covers (12 and 13) arranged on both sides of the housing (1).

2. The motorized spindle with a water-lubricated sliding bearing and a gas static pressure bearing conversion support according to claim 1, characterized in that: The front water-lubricated sliding pressure radial bearing (3) includes a front water-lubricated sliding pressure radial bearing bushing (301) and a front water-lubricated sliding pressure radial bearing journal (302). Among them, a first water inlet ring groove (303) is arranged in the middle of the front water-lubricated sliding pressure radial bearing bushing (301), and first and second pressure relief ring grooves (304 and 305) are arranged on both sides; the rear water-lubricated sliding pressure radial bearing (4) includes a rear water-lubricated sliding pressure radial bearing bushing (401) and a rear water-lubricated sliding pressure radial bearing journal (402). Among them, a second water inlet ring groove (403) is arranged in the middle of the rear water-lubricated sliding pressure radial bearing bushing (401), and a third pressure relief ring groove (404) is arranged on the front side; herringbone grooves (10) are arranged on the front and rear water-lubricated sliding pressure radial bearing journals (302 and 402), and a drainage cavity (1301) is arranged on the rear end cover (13).

3. The motorized spindle with a conversion support for a hydrostatic sliding bearing and a gas static pressure bearing according to claim 1, characterized in that: The water-lubricated sliding pressure thrust bearing (7) includes a thrust disc (701) and front and rear thrust pads (702 and 703). Among them, the front and rear thrust pads (702 and 703) are arranged on both sides of the thrust disc (701) and separated by an adjusting ring (704). Third and fourth water inlet ring grooves (705 and 706) are respectively arranged on their working surfaces, a fourth pressure relief ring groove (707) is arranged on the inner hole of the front thrust pad (702), and a drainage hole (708) is arranged on the adjusting ring (704); spiral grooves (1004) are arranged on the front and rear working surfaces of the thrust disc (701), and a gas sealing ring groove (1203) is arranged on the front end cover (12).

4. The motorized spindle with a conversion support for a hydrodynamic sliding bearing and a gas static pressure bearing according to claim 1, characterized in that: The front gas static pressure tapered bearing (5) is composed of a front gas bearing journal (501) and a front gas bearing bushing (502), and the rear gas static pressure tapered bearing (6) is composed of a rear gas bearing journal (601) and a rear gas bearing bushing (602); front and rear gas bearing inner sleeves (503 and 603) are respectively sleeved on the outer sides of the front and rear gas bearing bushings (502 and 602), and front and rear gas bearing outer sleeves (504 and 604) are sleeved on the inner side of the housing (1).

5. The motorized spindle with a conversion support for a hydrodynamic sliding bearing and a gas static pressure bearing according to claim 4, characterized in that: A number of raceways (510) are circumferentially arranged along the inner sides of the front and rear gas bearing outer sleeves (504 and 604). Ball bearings (511) are arranged in the raceways (510) for radial support and axial movement guidance of the front and rear gas bearing inner sleeves (503 and 603).

6. The motorized spindle with a hydrostatic sliding pressure and aerostatic bearing conversion support according to claim 4, characterized in that: On one side end faces of the front and rear gas bearing outer sleeves (504 and 604), a number of front and rear piston liquid-plastic extrusion cylinders (506 and 606) are respectively arranged circumferentially. Front and rear pistons (505 and 605) are respectively arranged in the front and rear piston liquid-plastic extrusion cylinders (506 and 606). Push rods (513) in the front and rear pistons (505 and 605) are respectively connected to the front and rear gas bearing inner sleeves (503 and 603) through screws (512).

7. The motorized spindle with a conversion support for a hydrostatic sliding bearing and a gas static pressure bearing according to claim 4, characterized in that: On one side end faces of the front and rear gas bearing inner sleeves (503 and 603) and on the corresponding housing (1), a number of spring holes (514) are respectively arranged circumferentially. Front and rear springs (507 and 607) are arranged in the spring holes (514). First and second intake annular grooves (508 and 608) are respectively arranged on the inner sides of the front and rear gas bearing inner sleeves (503 and 603).

8. The motorized spindle with a water-lubricated sliding and aerostatic bearing conversion support according to claim 1, characterized in that: The front and rear hydraulic regulating devices (8, 9) include a screw sleeve (801) arranged on the rear end cover (13), an adjusting screw (802) arranged in the screw sleeve (801), a plunger liquid-plastic extrusion cavity (804) arranged in the rear end cover (13), and a plunger (803) arranged in the plunger liquid-plastic extrusion cavity (804). Wherein, one side end face of the plunger (803) is in point contact with the ball at the end of the adjusting screw (802), the other side end face of the plunger (803) abuts against the liquid level of the liquid plastic (805), and the outer cylindrical surface of the plunger (803) is matched with the plunger liquid-plastic extrusion cavity (804) and keeps sealed.

9. The motorized spindle with a conversion support for a hydrostatic sliding bearing and a gas static pressure bearing according to claim 1 or 6, characterized in that: Front and rear liquid-plastic channels (116 and 117) are arranged in the housing (1). The front and rear piston liquid-plastic extrusion cylinders (506, 606) are respectively communicated with the plunger liquid-plastic extrusion cavities (804) in the front and rear hydraulic regulating devices (8 and 9) through the front and rear liquid-plastic channels (116 and 117), and are filled with liquid plastic (805).

10. The motorized spindle with a conversion support for a hydrostatic sliding bearing and a gas static pressure bearing according to claim 1 or 2 or 7, characterized in that: The housing (1) is provided with a main water inlet channel (101), a main gas-water discharge channel (102), a main air inlet channel (110) and a main exhaust channel (111); the first to fourth water inlet annular grooves (303, 403, 705 and 706) are respectively communicated with the main water inlet channel (101) through the first to fourth water inlet channels (103, 104, 1201 and 306); the first to fourth pressure relief annular grooves (304, 305, 404 and 707), the drainage cavity (1301) and the drainage hole (708) are respectively communicated with the main gas-water discharge channel (102) through the first drainage channel (108), the first to third gas-water discharge channels (105, 106 and 107), the second and third drainage channels (1302 and 109); the first to second air inlet annular grooves (508 and 608) and the airtight annular groove (1203) are respectively communicated with the main air inlet channel (110) through the first to third air inlet channels (112, 113 and 1202).

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