A small high-speed surface-throttled hydrostatic spindle

Abstract

The invention discloses a small-sized high-speed surface throttling fluid static pressure spindle, comprising a spindle, a front sleeve and a rear sleeve; the spindle is provided with a transition air hole d; the front end of the sleeve body of the front sleeve is radially provided with an air inlet a, the front sleeve is provided with an annular air passage b, an axial surface throttling slit c and a radial surface throttling slit e; the front end of the inner cavity of the rear sleeve is provided with an annular air passage b, the rear end of the inner cavity of the rear sleeve is provided with an axial surface throttling slit c, and the front end surface of the sleeve body of the rear sleeve is provided with a radial surface throttling slit e. The beneficial effects of the invention are: by adopting the surface throttling method, a rigid support can be formed without a throttle, high axial load, radial load, axial stiffness and radial stiffness can be provided, and perfect rotation accuracy and axial runout can be guaranteed at the same time, so as to realize high-speed chip cutting and grinding processing, and meet the working conditions of bearing a certain metal processing chip cutting force, the spindle still maintains very small axial runout and radial runout errors, thereby realizing various precision and ultra-precision processing.

Description

Technical Field

[0001] The invention relates to a spindle, in particular to a small-sized high-speed surface-throttling fluid static pressure spindle, belonging to the technical field of ultra-precision machining. Background Art

[0002] The gas static pressure spindle is a sliding bearing spindle that uses gas as lubrication. It relies on the high-pressure gas introduced from the outside to form a high-pressure lubrication film around the shaft, providing support stiffness and carrying external loads. The most notable features are high rotation accuracy, the lubricating medium is gas, the bearing friction coefficient is small, it can move at extremely low speeds, there is no creeping phenomenon, it has high positioning accuracy and repeated positioning accuracy, there is no wear in normal working conditions, and the heat generation is very small. The main disadvantages are low stiffness, poor damping, and weak bearing capacity.

[0003] The throttling modes of gas hydrostatic bearings in the prior art include: small hole throttling, porous throttling, slit throttling and surface throttling; among them, the small hole throttling has very high processing and manufacturing requirements, a large number of throttling devices, low consistency of small hole diameters, and there may be leakage during installation, which is prone to air hammer phenomenon; porous throttling consumes a lot of gas, and the porous material has very high requirements for the gas source, and the pores are easily blocked; slit throttling has very high processing and manufacturing requirements; surface throttling is currently only at the theoretical level. Summary of the invention

[0004] The object of the present invention is to provide a small, high-speed, surface-throttled hydrostatic spindle in order to solve at least one of the above-mentioned technical problems.

[0005] The present invention achieves the above-mentioned purpose through the following technical scheme: a small high-speed surface throttling fluid static pressure spindle, comprising a spindle, a front shaft sleeve is sleeved on the front shaft body of the spindle, a rear shaft sleeve is sleeved on the rear shaft body of the spindle, and a motor is coaxially connected to the rear end of the spindle;

[0006] The main shaft is a T-shaped structure, with a smooth cylindrical surface in the axial direction and a circular flange plate in the radial direction. A transition air hole d is opened at the flange plate of the main shaft;

[0007] An air inlet a is radially provided at the front end of the sleeve body of the front sleeve, an annular air passage b is provided at the front end of the inner cavity of the front sleeve, and the air inlet a is communicated with the annular air passage b, an axial surface throttling slit c is provided at the rear end of the inner cavity of the front sleeve, and a radial surface throttling slit e is provided at the front end surface of the sleeve body of the front sleeve;

[0008] An annular air passage b is provided at the front end of the inner cavity of the rear sleeve, an axial surface throttling slit c is provided at the rear end of the inner cavity of the rear sleeve, and a radial surface throttling slit e is provided at the front end surface of the sleeve body of the rear sleeve.

[0009] As a further solution of the present invention: the length of the axial surface throttling slot c opened in the inner cavity of the front sleeve is smaller than the length of the main shaft wrapped by the front sleeve, the axial surface throttling slot c is evenly distributed along the circumference of the axial surface of the inner cavity of the front sleeve, the length of the radial surface throttling slot e opened on the front end face of the front sleeve body is smaller than the diameter of the radial circular flange plate of the main shaft, and the radial surface throttling slot e is evenly distributed in a fan shape on the radial end face.

[0010] As a further solution of the present invention: the length of the axial surface throttling slot c opened in the inner cavity of the rear sleeve is smaller than the length of the wrapped main shaft, the axial surface throttling slot c is evenly distributed along the circumference of the axial surface of the inner cavity of the rear sleeve, the length of the radial surface throttling slot e opened on the front end face of the rear sleeve body is smaller than the diameter of the radial circular flange plate of the main shaft, and the radial surface throttling slot e is evenly distributed in a fan shape on the radial end face.

[0011] As a further solution of the present invention: the front bushing and the rear bushing are installed coaxially with the main shaft, and the matching clearance range is 5μm-50μm.

[0012] As a further solution of the present invention: the throttling end face of the radial surface of the front sleeve and the throttling end face of the radial surface of the rear sleeve are matched with the two end faces of the main shaft circular flange plate, and the matching clearance is adjusted by the clearance adjustment seat, and the matching clearance range is 5μm-50μm.

[0013] As a further solution of the present invention: an encoder is installed at the end of the spindle, and the rotation accuracy and axial runout of the spindle are both less than 70nm.

[0014] As a further solution of the present invention: the rear shaft sleeve is installed in the main shaft seat, the front shaft sleeve end face is connected to the main shaft seat end face, and the front shaft sleeve body is concentrically sleeved with a front outer sleeve outside, and both the main shaft seat and the front outer sleeve have mounting holes for installing quick plugs.

[0015] As a further solution of the present invention: an annular flow channel is opened on the outer surface of the rear sleeve and the outer surface of the front sleeve, and cooling water enters through one end of the quick plug and flows out from the other end of the quick plug through the annular flow channel.

[0016] As a further solution of the present invention: a rear cover is installed on the other end face of the main shaft seat, a second muffler is installed on the rear cover, and the rear cover has a threading hole and an aviation plug installation hole, and the installation hole opened at the bottom of the main shaft seat is installed with the first muffler.

[0017] As a further solution of the present invention: the front and rear ends of the mating surface between the front sleeve and the front outer sleeve are respectively provided with a first sealing ring and a second sealing ring, the front and rear ends of the mating surface between the rear sleeve and the main shaft seat are respectively provided with a third sealing ring and a fourth sealing ring, and the mating surface between the front sleeve and the main shaft seat is provided with a fifth sealing ring.

[0018] The beneficial effects of the present invention are:

[0019] 1) The surface throttling method is adopted, and a transition air hole d is opened on the main shaft; the front shaft sleeve is provided with an air inlet a, an annular air channel b, an axial surface throttling slit c and a radial surface throttling slit e; the rear shaft sleeve is provided with an annular air channel b, an axial surface throttling slit c and a radial surface throttling slit e. The gas forms a uniform lubricating film on the cylindrical surface of the main shaft and the two end surfaces of the radial circular flange of the main shaft. The gas overflowing through the lubricating film is discharged from the main shaft through the exhaust port. The axial surface throttling passes through the tail of the main shaft, passes through the motor, and is discharged from the second muffler installed on the rear cover;

[0020] 2) The gas overflowed by radial surface throttling is also discharged in two ways: one way passes through the overflow hole of the gap adjustment seat and is discharged from the first muffler on the bottom of the spindle seat, and the other way passes through the exhaust hole of the spindle seat and flows to the rear cover and the second muffler for discharge. Rigid support can be formed without a throttle, providing higher axial load, radial load, axial stiffness, and radial stiffness, while ensuring perfect rotation accuracy and axial runout, and realizing high-speed chip cutting and grinding. Under the condition of bearing a certain metal processing cutting force, the spindle still maintains very small axial runout and radial runout errors, thereby realizing various precision and ultra-precision processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall assembly structure of the present invention;

[0022] Figure 2 It is a schematic diagram of gas flow of the present invention;

[0023] Figure 3 This is a schematic diagram of the main shaft structure of the present invention;

[0024] Figure 4 It is a schematic diagram of the front shaft sleeve structure of the present invention;

[0025] Figure 5 It is a schematic diagram of the rear axle sleeve structure of the present invention.

[0026] In the figure: 1, front bushing, 2, front outer sleeve, 3, rear bushing, 4, motor, 5, spindle seat, 6, rear cover, 7, quick plug, 8, first sealing ring, 9, second sealing ring, 10, third sealing ring, 11, fourth sealing ring, 12, fifth sealing ring, 13, spindle, 14, gap adjustment seat, 15, first muffler, 16, second muffler, 17, encoder. DETAILED DESCRIPTION

[0027] 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.

[0028] Embodiment 1, as Figures 1 to 5 As shown, a small-sized high-speed surface-throttled hydrostatic spindle comprises a spindle 13, a front shaft sleeve 1 is sleeved on the front shaft body of the spindle 13, a rear shaft sleeve 3 is sleeved on the rear shaft body of the spindle 13, and a motor 4 is coaxially connected to the rear end of the spindle 13;

[0029] The main shaft 13 is a T-shaped structure, the main shaft 13 is a smooth cylindrical surface in the axial direction, and a circular flange plate in the radial direction. The main shaft 13 is provided with a transition air hole d at the flange plate;

[0030] An air inlet a is radially provided at the front end of the sleeve body of the front sleeve 1, an annular air passage b is provided at the front end of the inner cavity of the front sleeve 1, and the air inlet a is communicated with the annular air passage b, an axial surface throttling slit c is provided at the rear end of the inner cavity of the front sleeve 1, and a radial surface throttling slit e is provided at the front end surface of the sleeve body of the front sleeve 1;

[0031] An annular air passage b is provided at the front end of the inner cavity of the rear sleeve 3 , an axial surface throttling slit c is provided at the rear end of the inner cavity of the rear sleeve 3 , and a radial surface throttling slit e is provided at the front end surface of the sleeve body of the rear sleeve 3 .

[0032] Embodiment 2. In addition to all the technical features of Embodiment 1, this embodiment also includes: the length of the axial surface throttling slot c opened in the inner cavity of the front shaft sleeve 1 is less than the length of the main shaft 13 wrapped by the front shaft sleeve 1, the axial surface throttling slot c is evenly distributed along the circumference of the axial surface of the inner cavity of the front shaft sleeve 1, the length of the radial surface throttling slot e opened on the front end face of the front shaft sleeve 1 is less than the diameter of the radial circular flange plate of the main shaft 13, and the radial surface throttling slot e is evenly distributed in a fan shape on the radial end face.

[0033] The length of the axial surface throttling slot c opened in the inner cavity of the rear sleeve 3 is smaller than the length of the wrapped main shaft 13, and the axial surface throttling slot c is evenly distributed along the circumference of the axial surface of the inner cavity of the rear sleeve 3. The length of the radial surface throttling slot e opened on the front end face of the rear sleeve 3 is smaller than the diameter of the radial circular flange plate of the main shaft 13, and the radial surface throttling slot e is evenly distributed in a fan shape on the radial end face.

[0034] Embodiment 3, in addition to all the technical features of Embodiment 1, this embodiment also includes: the front bushing 1, the rear bushing 3 are coaxially installed with the main shaft 13, and the fitting clearance range is 5μm-50μm.

[0035] The throttling end faces of the radial surfaces of the front sleeve 1 and the rear sleeve 3 are matched with the two end faces of the circular flange plate of the main shaft 13, and the matching clearance is adjusted by the clearance adjustment seat 14, and the matching clearance range is 5μm-50μm.

[0036] An encoder 17 is installed at the end of the spindle 13, and the rotation accuracy and axial runout of the spindle 13 are both less than 70nm, so the rotation accuracy and axial runout of the spindle 13 are accurately controlled.

[0037] Embodiment 4, in addition to all the technical features of Embodiment 1, this embodiment also includes: the rear shaft sleeve 3 is installed in the main shaft seat 5, the end face of the front shaft sleeve 1 is connected to the end face of the main shaft seat 5, and the front shaft sleeve 1 is concentrically sleeved on the outer side of the sleeve body with a front outer sleeve 2, and both the main shaft seat 5 and the front outer sleeve 2 have mounting holes for installing a quick plug 7.

[0038] Annular flow channels are provided on the outer surfaces of the rear sleeve 3 and the front sleeve 1. Cooling water enters through one end of the quick plug 7 and flows out from the other end of the quick plug 7 through the annular flow channel, effectively taking away the heat generated by the internal movement of the spindle.

[0039] A rear cover 6 is installed on the other end face of the spindle seat 5, and a second muffler 16 is installed on the rear cover 6. The rear cover 6 has a threading hole and an aviation plug installation hole for passing the wire and installing the aviation plug. The installation hole opened at the bottom of the spindle seat 5 is installed with a first muffler 15. The first muffler 15 is installed to remove the gas overflowing from the spindle.

[0040] The front and rear ends of the mating surfaces between the front sleeve 1 and the front outer sleeve 2 are respectively provided with a first sealing ring 8 and a second sealing ring 9, the front and rear ends of the mating surfaces between the rear sleeve 3 and the main shaft seat 5 are respectively provided with a third sealing ring 10 and a fourth sealing ring 11, and the mating surfaces between the front sleeve 1 and the main shaft seat 5 are provided with a fifth sealing ring 12.

[0041] Working principle: The air inlet a is on the front sleeve 1, perpendicular to the axis of the main shaft 13. After passing through the air inlet a, the gas enters the annular airway b. The annular airway is larger than the diameter of the main shaft 13. The gas will evenly radially wrap the main shaft 13 in the annular airway. The gas is divided into three paths in the annular airway. One path flows to the radial surface throttling slit of the front sleeve 1, one path flows to the axial surface throttling slit of the front sleeve 1, and another path flows to the radial circular flange plate of the main shaft through the main shaft transition air hole d, and then is divided into two paths again. The radial surface throttling slit and the axial surface throttling slit of the rear sleeve 3 The gas forms a uniform lubricating film on the cylindrical surface of the main shaft 13 and the two end surfaces of the radial circular flange of the main shaft. The gas overflowing through the lubricating film is discharged from the main shaft through the exhaust port. The axial surface throttling passes through the tail of the main shaft 13, passes through the motor 4, and is discharged from the second muffler 16 installed on the rear cover 6; the gas overflowing from the radial surface throttling is also divided into two exhaust paths. One path passes through the overflow hole of the gap adjustment seat 14 and is discharged from the first muffler 15 on the bottom surface of the main shaft seat 5, and the other path passes through the exhaust hole of the main shaft seat 5 and flows to the rear cover 6 and the second muffler 16 for discharge.

[0042] 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.

[0043] 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. A small high-speed surface-throttled hydrostatic spindle, comprising a spindle (13), characterized in that: A front shaft sleeve (1) is sleeved on the front shaft body of the main shaft (13), a rear shaft sleeve (3) is sleeved on the rear shaft body of the main shaft (13), and a motor (4) is coaxially connected to the rear end of the main shaft (13); The main shaft (13) is a T-shaped structure, the main shaft (13) is a smooth cylindrical surface in the axial direction and a circular flange plate in the radial direction, and the main shaft (13) is provided with a transition air hole d at the flange plate; The front end of the sleeve body of the front sleeve (1) is radially provided with an air inlet a, the front end of the inner cavity of the front sleeve (1) is provided with an annular air passage b, and the air inlet a is communicated with the annular air passage b, the rear end of the inner cavity of the front sleeve (1) is provided with an axial surface throttling slit c, and the front end surface of the sleeve body of the front sleeve (1) is provided with a radial surface throttling slit e; An annular air passage b is provided at the front end of the inner cavity of the rear shaft sleeve (3), an axial surface throttling slit c is provided at the rear end of the inner cavity of the rear shaft sleeve (3), and a radial surface throttling slit e is provided at the front end surface of the sleeve body of the rear shaft sleeve (3); The length of the axial surface throttling slit c formed in the inner cavity of the front shaft sleeve (1) is smaller than the length of the main shaft (13) wrapped by the front shaft sleeve (1), the axial surface throttling slit c is evenly distributed along the circumference of the axial surface of the inner cavity of the front shaft sleeve (1), the length of the radial surface throttling slit e formed in the front end surface of the front shaft sleeve (1) is smaller than the diameter of the radial circular flange plate of the main shaft (13), and the radial surface throttling slit e is evenly distributed in a fan shape on the radial end surface; The length of the axial surface throttling slit c formed in the inner cavity of the rear shaft sleeve (3) is less than the length of the wrapped main shaft (13), the axial surface throttling slit c is evenly distributed along the circumference of the axial surface of the inner cavity of the rear shaft sleeve (3), the length of the radial surface throttling slit e formed in the front end surface of the sleeve body of the rear shaft sleeve (3) is less than the diameter of the radial circular flange plate of the main shaft (13), and the radial surface throttling slit e is evenly distributed in a fan shape on the radial end surface; The rear shaft sleeve (3) is installed in the main shaft seat (5), the end face of the front shaft sleeve (1) is connected to the end face of the main shaft seat (5), and a front outer sleeve (2) is concentrically sleeved on the outer side of the sleeve body of the front shaft sleeve (1), and both the main shaft seat (5) and the front outer sleeve (2) have mounting holes for mounting a quick plug (7).

2. The hydrostatic spindle according to claim 1, characterized in that: The front shaft sleeve (1) and the rear shaft sleeve (3) are coaxially mounted with the main shaft (13), and the matching clearance range is 5 μm-50 μm.

3. The hydrostatic spindle according to claim 2, characterized in that: The throttling end face of the radial surface of the front shaft sleeve (1) and the throttling end face of the radial surface of the rear shaft sleeve (3) are matched with the two end faces of the circular flange plate of the main shaft (13), and the matching clearance is adjusted by the clearance adjustment seat (14), and the matching clearance range is 5μm-50μm.

4. The hydrostatic spindle according to claim 1, characterized in that: An encoder (17) is installed at the end of the spindle (13), and the rotational accuracy and axial runout of the spindle (13) are both less than 70 nm, so that the rotational accuracy and axial runout of the spindle (13) are accurately controlled.

5. The hydrostatic spindle according to claim 1, characterized in that: The outer surfaces of the rear shaft sleeve (3) and the front shaft sleeve (1) are both provided with an annular flow channel, and cooling water enters through one end of the quick plug (7) and flows out through the annular flow channel from the other end of the quick plug (7).

6. The hydrostatic spindle according to claim 1, characterized in that: A rear cover (6) is installed on the other end surface of the main shaft seat (5), a second muffler (16) is installed on the rear cover (6), and the rear cover (6) has a threading hole and an aviation plug installation hole, and the first muffler (15) is installed in the installation hole opened at the bottom of the main shaft seat (5).

7. The hydrostatic spindle according to claim 6, characterized in that: A first sealing ring (8) and a second sealing ring (9) are respectively sleeved on the front and rear ends of the mating surface between the front shaft sleeve (1) and the front outer sleeve (2); a third sealing ring (10) and a fourth sealing ring (11) are respectively sleeved on the front and rear ends of the mating surface between the rear shaft sleeve (3) and the main shaft seat (5); and a fifth sealing ring (12) is sleeved on the mating surface between the front shaft sleeve (1) and the main shaft seat (5).

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