Air floatation A shaft capable of being applied to ultra-precision machining

Abstract

The air floatation A shaft capable of being applied to ultra-precision machining comprises an outer taper sleeve, a shaft seat, a motor shaft and a torque motor, a conical shaft core and a lower thrust are further arranged in the shaft seat, and communicated air channels are formed in the outer taper sleeve, the lower thrust and the shaft seat. The air floatation A shaft has the beneficial effects that compressed air enters the air floatation A shaft through the pneumatic connector installed on the shaft seat, air films are formed between the outer taper sleeve and the conical shaft core and between the lower thrust and the conical shaft core through the air channels in the outer taper sleeve and the lower thrust, and the flow speed of the compressed air entering the air channels is controlled through the throttler; therefore, the formed gas film can be kept stable; the position control precision and the long-term stability of a moving part are remarkably improved in a non-contact supporting mode, a double-cone structure is adopted, so that the bearing works more stably and has better precision, the precision of an air floating rotary table is improved, and the air floating A shaft has better stability and accuracy.

Description

Technical Field

[0001] The invention relates to an air-floating A-axis, in particular to an air-floating A-axis applicable to ultra-precision machining, and belongs to the technical field of precision optical parts machining and application. Background Art

[0002] The A-axis of the traditional CNC machining center is a mechanical turntable. The main structural type of the mechanical turntable is a motor plus a rolling bearing drive. The air-floating shaft is a rotating shaft structure that uses gas instead of the transmission lubricating oil as a lubricant. Compared with the traditional shaft structure, it has the advantages of easy maintenance and small rotation resistance.

[0003] In the prior art, there is a novel air-floating shaft disclosed in announcement number CN103994145A, which includes a main shaft and a machine body. The main shaft includes a main body and two shaft heads, the diameter of the shaft heads is smaller than the diameter of the main body, and two ends of the main body form a pressure surface respectively, and a thrust bearing is respectively arranged on the outer side of the two pressure surfaces; a plurality of axial damping plugs are evenly distributed on the thrust bearing; a plurality of radial damping plugs are arranged on the machine body, and the plurality of radial damping plugs are arranged in a plurality of rows; the two thrust bearings are fixedly connected to the machine body, and a plurality of first channels are arranged on the thrust bearing, the inner end of the first channel is connected to the first air inlet of the axial damping plug, and the outer ends of the first channel are connected to each other; a plurality of second channels are arranged on the machine body, which extend along the axial direction of the machine body and connect the first channels on the two thrust bearings, and each second channel corresponds to a row of radial damping plugs. The air-floating shaft of the present invention increases the radial load-bearing capacity and rigidity of the main shaft by increasing the diameter of the main part of the main shaft, thereby ensuring the rotation accuracy of the main shaft when rotating. However, the existing air-floating shaft adopts the method of increasing the radial load-bearing capacity and rigidity of the main shaft to improve the rotation accuracy. However, for the bearings connected to the main shaft, the rotating shaft system supported by the rolling bearings may cause increased positioning errors due to wear after long-term operation, and the accuracy will gradually decrease, which cannot meet the requirements of ultra-precision machining. The bearings cannot ensure stable operation, which will lead to the inability to further improve the accuracy of the air-floating shaft. Summary of the invention

[0004] The purpose of the present invention is to provide an air-bearing A-axis applicable to ultra-precision machining in order to solve at least one of the above technical problems.

[0005] The present invention achieves the above-mentioned purpose through the following technical scheme: an air-floating A-axis applicable to ultra-precision machining, comprising an outer tapered sleeve, a shaft seat, a motor shaft and a torque motor, wherein the outer tapered sleeve is installed in the shaft seat, and the outer tapered sleeve is located at the front end of the shaft seat, the motor shaft is coaxially rotatably connected in the shaft seat, the torque motor is arranged in the shaft seat, the torque motor comprises a stator and a rotor, the stator of the torque motor is fixedly connected to the shaft seat, and the rotor of the torque motor is fixed on the shaft body of the motor shaft; A conical shaft core and a lower thrust stop are also provided in the shaft seat. The conical shaft core is fixedly connected to the motor shaft coaxially. The conical surface of the conical shaft core fits the inner surface of the outer conical sleeve. The lower thrust sleeve is arranged on the shaft body of the motor shaft, and the installation position of the lower thrust stop is located between the torque motor and the conical shaft core. An air passage connecting the outer conical sleeve, the lower thrust stop and the inside of the shaft seat is opened, and a throttle is fixedly connected in the air passage. The tail end of the shaft seat is connected to a pneumatic joint, and the pneumatic joint is connected to the air passage opened in the shaft seat.

[0006] As a further solution of the present invention: the stator of the torque motor is fixedly connected to the shaft seat through a first locking nut, and the rotor of the torque motor is fixed to the shaft body of the motor shaft through a second locking nut.

[0007] As a further solution of the present invention, the air passages opened inside the outer cone sleeve and the lower thrust are provided with a plurality of ring-shaped air passages, and the throttle is fixed in the air passages opened between the outer cone sleeve and the lower thrust by bonding.

[0008] As a further solution of the present invention: a front mounting disk is coaxially arranged at the front end of the motor shaft, one side of the disk body of the front mounting disk is fixedly connected to the conical shaft core by bolts, and the other side of the disk body of the front mounting disk is fixedly connected to a chuck by bolts.

[0009] As a further solution of the present invention: the tail end of the motor shaft is fixedly connected to a grating ruler mounting seat, and a circular grating is mounted on the grating ruler mounting seat, the tail end of the shaft seat is connected to a reading head, and the installation position of the reading head is aligned with the circular grating.

[0010] As a further solution of the present invention: the rear open end of the shaft seat is fixedly connected with a rear cover by bolts, a vacuum ring is arranged in the rear inner cavity of the shaft seat, a connecting column is connected between the vacuum ring and the grating scale mounting seat, a through hole connecting the motor shaft and the front mounting disk, the rear cover is connected to one side of the vacuum ring through a pipe joint, and the other side of the vacuum ring is connected to the through hole opened by the motor shaft.

[0011] As a further solution of the present invention: two sets of electrical connectors are connected to the outer side wall of the rear end of the shaft seat, the torque motor is electrically connected to the external power supply through one of the electrical connectors, and the reading head is connected to the external terminal for signal transmission through the other electrical connector.

[0012] The beneficial effects of the present invention are as follows: the present invention is provided with an outer tapered sleeve, a shaft seat, a motor shaft and a torque motor, a tapered shaft core and a lower thrust are further provided in the shaft seat, a communicating air passage is opened inside the outer tapered sleeve, the lower thrust and the shaft seat, and a throttle is fixedly connected in the air passage, so that compressed air enters the air-floating A-axis through a pneumatic joint installed on the shaft seat, an air film is formed between the outer tapered sleeve and the tapered shaft core and between the lower thrust and the tapered shaft core through the air passage in the outer tapered sleeve and the lower thrust, and the flow rate of the compressed air entering the air passage is controlled by the throttle, thereby ensuring that the formed air film can remain stable, and the tapered shaft core and the outer tapered sleeve adopt a docking structure with matching tapered surfaces, so that the air-floating A-axis has better stability and accuracy; The present invention significantly improves the position control accuracy and long-term stability of moving parts through a non-contact support method, adopts a double-cone structure type, makes the bearing work more stably, has better accuracy, and improves the accuracy of the air-floating turntable. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the cross-sectional structure of the present invention; Figure 2 It is a schematic diagram of the top view structure of the present invention; Figure 3 It is a schematic diagram of the appearance structure of the present invention.

[0014] In the figure: 1, outer tapered sleeve, 2, tapered shaft core, 3, lower thrust, 4, shaft seat, 5, motor shaft, 6, first locking nut, 7, grating scale mounting seat, 8, reading head seat, 9, rear cover, 10, vacuum ring, 11, connecting column, 12, throttle, 13, front mounting plate, 14, electrical connector, 15, pneumatic connector, 16, torque motor, 17, second locking nut, 18, reading head, 19, circular grating, 20, chuck. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] Embodiment 1, as Figures 1 to 3As shown, an air-bearing A-axis applicable to ultra-precision machining comprises an outer tapered sleeve 1, a shaft seat 4, a motor shaft 5 and a torque motor 16, wherein the outer tapered sleeve 1 is installed in the shaft seat 4, and the outer tapered sleeve 1 is located at the front end of the shaft seat 4, the motor shaft 5 is coaxially rotatably connected in the shaft seat 4, the torque motor 16 is arranged in the shaft seat 4, and the torque motor 16 comprises a stator and a rotor, the stator of the torque motor 16 is fixedly connected to the shaft seat 4, and the rotor of the torque motor 16 is fixed on the shaft body of the motor shaft 5; The shaft seat 4 is also provided with a conical shaft core 2 and a lower thrust 3, the conical shaft core 2 is coaxially fixedly connected to the motor shaft 5, the conical surface of the conical shaft core 2 fits the inner side of the outer conical sleeve 1, the lower thrust 3 is sleeved on the shaft body of the motor shaft 5, and the installation position of the lower thrust 3 is located between the torque motor 16 and the conical shaft core 2, the outer conical sleeve 1, the lower thrust 3 and the shaft seat 4 are provided with a communicating airway, and a throttle 12 is fixedly connected in the airway, the tail end of the shaft seat 4 is connected to a pneumatic joint 15, and the pneumatic joint 15 and the shaft seat 4 are provided with a pneumatic joint 15. The air passages are connected so that the compressed air can enter the air-floating A-axis through the pneumatic joint 15 installed on the shaft seat 4, and an air film is formed between the outer cone sleeve 1 and the tapered shaft core 2 and between the lower thrust 3 and the tapered shaft core 2 through the air passages in the outer cone sleeve 1 and the lower thrust 3. The flow rate of the compressed air entering the air passage is controlled by the throttle 12, thereby ensuring that the formed air film can remain stable. The tapered shaft core 2 and the outer cone sleeve 1 adopt a docking structure with matching tapered surfaces, so that the air-floating A-axis has better stability and accuracy.

[0017] Embodiment 2. In addition to all the technical features of Embodiment 1, this embodiment also includes: the stator of the torque motor 16 is fixedly connected to the shaft seat 4 through the first locking nut 6, and the rotor of the torque motor 16 is fixed to the shaft body of the motor shaft 5 through the second locking nut 17 to ensure that the torque motor 16 can be firmly connected between the shaft seat 4 and the motor shaft 5, and the stator of the torque motor 16 is fixed by the shaft seat 4, so that the rotor of the torque motor 16 can drive the motor shaft 5 to rotate.

[0018] The air passages opened inside the outer cone sleeve 1 and the lower thrust 3 are provided with multiple ring-shaped air passages, and the throttle 12 is fixed in the air passages opened by the outer cone sleeve 1 and the lower thrust 3 by bonding to ensure that the compressed air passes through the ring-shaped air passages evenly into the space between the outer cone sleeve 1 and the conical shaft core 2 and between the lower thrust 3 and the conical shaft core 2, thereby forming a more stable air film.

[0019] Embodiment three, in addition to all the technical features of embodiment one, this embodiment also includes: a front mounting disk 13 is coaxially arranged at the front end of the motor shaft 5, one side of the disk body of the front mounting disk 13 is fixedly connected to the conical shaft core 2 by bolts, and the other side of the disk body of the front mounting disk 13 is fixedly connected to a chuck 20 by bolts, so that the air-floating A-axis can use the chuck 20 to install the workpiece, and then the workpiece installed on the chuck 20 can be driven to rotate by the rotation of the motor shaft 5 to realize the processing of the workpiece.

[0020] The tail end of the motor shaft 5 is fixedly connected to a grating ruler mounting seat 7, and a circular grating 19 is mounted on the grating ruler mounting seat 7. The tail end of the shaft seat 4 is connected to a reading head 18, and the installation position of the reading head 18 is aligned with the circular grating 19. When the motor shaft 5 rotates, the circular grating 19 can be driven to rotate, and then the rotation accuracy of the circular grating 19 can be read by the reading head 18, so that the air-floating A-axis has a very high positioning accuracy, and can achieve precise control of the rotation speed through the Hall element of the torque motor 16.

[0021] The rear open end of the shaft seat 4 is fixedly connected to the rear cover 9 by bolts, and a vacuum ring 10 is arranged in the rear inner cavity of the shaft seat 4. A connecting column 11 is connected between the vacuum ring 10 and the grating scale mounting seat 7. A through hole is provided to connect the motor shaft 5 and the front mounting disk 13. The rear cover 9 is connected to one side of the vacuum ring 10 through a pipe joint, and the other side of the vacuum ring 10 is connected to the through hole provided by the motor shaft 5, so that the vacuum can be transmitted to the use surface of the air-floating A-axis, and the function of vacuum adsorption can be realized to adsorb and fix the workpiece.

[0022] Two sets of electrical connectors 14 are connected to the outer rear wall of the shaft seat 4. The torque motor 16 is electrically connected to the external power supply through one of the electrical connectors 14, and the reading head 18 is connected to the external terminal for signal transmission through the other electrical connector 14, so as to control the opening and closing of the torque motor 16 and the reading head 18 can transmit the rotation accuracy information read to the external terminal, so as to accurately control the accuracy of the air-floating A-axis.

[0023] The air-floating A-axis can use a chuck 20 to install the workpiece, and can also transmit the vacuum to the use surface of the air-floating A-axis through a vacuum ring 10, so as to realize the function of vacuum adsorption to adsorb and fix the workpiece, and then the workpiece installed on the chuck 20 can be driven to rotate by the rotation of the motor shaft 5 to realize the processing of the workpiece. When the motor shaft 5 rotates, compressed air enters the air-floating A-axis through the pneumatic joint 15 installed on the shaft seat 4, and an air film is formed between the outer tapered sleeve 1 and the tapered shaft core 2 and between the lower thrust 3 and the tapered shaft core 2 through the air passages in the outer tapered sleeve 1 and the lower thrust 3, and the flow rate of the compressed air entering the air passage is controlled by the throttle 12, so as to ensure that the formed air film can remain stable. The tapered shaft core 2 and the outer tapered sleeve 1 adopt a docking structure with matching tapered surfaces, so that the air-floating A-axis has better stability and accuracy.

[0024] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0025] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An air-bearing A-axis applicable to ultra-precision machining, comprising an outer tapered sleeve (1), a shaft seat (4), a motor shaft (5) and a torque motor (16), characterized in that: The outer conical sleeve (1) is installed in the shaft seat (4), and the outer conical sleeve (1) is located at the front end of the shaft seat (4); a motor shaft (5) is coaxially rotatably connected in the shaft seat (4); the torque motor (16) is arranged in the shaft seat (4); the torque motor (16) comprises a stator and a rotor; the stator of the torque motor (16) is fixedly connected to the shaft seat (4), and the rotor of the torque motor (16) is fixed on the shaft body of the motor shaft (5); A conical shaft core (2) and a lower thrust (3) are also provided in the shaft seat (4); the conical shaft core (2) is coaxially fixedly connected to the motor shaft (5); the conical surface of the conical shaft core (2) fits the inner surface of the outer conical sleeve (1); the lower thrust (3) is sleeved on the shaft body of the motor shaft (5); and the installation position of the lower thrust (3) is located between the torque motor (16) and the conical shaft core (2); a communicating air passage is provided inside the outer conical sleeve (1), the lower thrust (3) and the shaft seat (4); and a throttle (12) is fixedly connected inside the air passage; a pneumatic joint (15) is connected to the rear end of the shaft seat (4); and the pneumatic joint (15) is communicated with the air passage provided inside the shaft seat (4).

2. The air-bearing A-axis according to claim 1, characterized in that: The stator of the torque motor (16) is fixedly connected to the shaft seat (4) via a first locking nut (6), and the rotor of the torque motor (16) is fixed to the shaft body of the motor shaft (5) via a second locking nut (17).

3. The air-bearing A-axis according to claim 1, characterized in that: The air passages opened inside the outer cone sleeve (1) and the lower thrust (3) are provided in a plurality of ring-shaped sections, and the throttle (12) is fixed in the air passages opened inside the outer cone sleeve (1) and the lower thrust (3) by bonding.

4. The air-bearing A-axis according to claim 1, characterized in that: A front mounting plate (13) is coaxially arranged at the front end of the motor shaft (5); one side of the plate body of the front mounting plate (13) is fixedly connected to the conical shaft core (2) via bolts; and the other side of the plate body of the front mounting plate (13) is fixedly connected to a chuck (20) via bolts.

5. The air-bearing A-axis according to claim 1, characterized in that: The tail end of the motor shaft (5) is fixedly connected to a grating ruler mounting seat (7), and a circular grating (19) is mounted on the grating ruler mounting seat (7); the tail end of the shaft seat (4) is connected to a reading head (18), and the installation position of the reading head (18) is aligned with the circular grating (19).

6. The air-bearing A-axis according to claim 1, characterized in that: The rear open end of the shaft seat (4) is fixedly connected to a rear cover (9) by bolts, a vacuum ring (10) is arranged in the rear inner cavity of the shaft seat (4), a connecting column (11) is connected between the vacuum ring (10) and the grating scale mounting seat (7), a through hole is provided in communication with the motor shaft (5) and the front mounting plate (13), the rear cover (9) is connected to one side of the vacuum ring (10) by a pipe joint, and the other side of the vacuum ring (10) is connected to the through hole provided on the motor shaft (5).

7. The air-bearing A-axis according to claim 1, characterized in that: The rear outer side wall of the shaft seat (4) is connected to two sets of electrical connectors (14); the torque motor (16) is electrically connected to an external power source via one of the electrical connectors (14); and the reading head (18) is connected to an external terminal for signal transmission via another electrical connector (14).

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