A spindle assembly structure and locking method for a hemispherical bearing

Abstract

The invention discloses a spindle assembly structure and locking method of a hemispherical bearing, wherein the assembly structure comprises: a box body, in which the spindle is inserted; a left hemisphere and a right hemisphere are arranged at two ends of the spindle; the outer end face of the right hemisphere is fixedly connected with the T-shaped end face of the spindle by a first screw; a left bearing cover is arranged at the outer side of the left hemisphere, and a right bearing cover is arranged at the outer side of the right hemisphere; a transition piece is sleeved at the outer side of one end of the spindle close to the left hemisphere, and is threadedly connected with the spindle; the transition piece is fixedly connected with the end of the left hemisphere by a third screw; a positioning retaining ring is extended on one side of the transition piece close to the left hemisphere, and a positioning groove is arranged at the position corresponding to the positioning retaining ring of the left hemisphere; a locking block is arranged at one end of the transition plate away from the left hemisphere, the locking block is integrally connected with the transition plate, and a fourth screw for locking the axial thread of the spindle is fixed on the surface of the locking block. The locking effect of the assembly of the hemispherical bearing and the spindle in the invention is more reliable, and the assembly error is small.

Description

Technical Field

[0001] The invention relates to the technical field of automated machine tool devices, and more particularly to a spindle assembly structure and a locking method for a hemispherical bearing. Background Art

[0002] The spindle of the existing hemispherical bearing structure mostly adopts the front and rear hemispheres to be positioned radially through the spindle 1 and the hemispheres 2 and 6, and the bearing clearance is adjusted axially through the precision thread of the transition plate 7, and the locking nut 8 is used for axial fixing and locking. Figure 1 As shown. And in the Chinese patent with publication number CN105478808A published on November 21, 2017, it is also disclosed that the hemisphere is axially positioned by a locking nut.

[0003] In the existing hemispherical bearing structure, the spindle 1 and hemispheres 2 and 6 are assembled by grinding a small gap; the coaxiality between the hemisphere surface and the inner hole can reach about level 3 accuracy due to the limitation of machine tool processing accuracy; the verticality between the end surface connecting the spindle 1 and hemisphere 2 and the spindle axis can be guaranteed to be about level 4 accuracy due to the limitation of machine tool processing accuracy. All processing errors will be accumulated and superimposed after assembly, resulting in the misalignment between the center of the hemisphere and the spindle axis after actual assembly, and the misalignment degree is about level 5 accuracy. The accumulated errors after assembly will affect the subsequent assembly accuracy of the built-in motor and the encoder, and will also cause vibration when the spindle is at high speed.

[0004] At the same time, the existing spindle structure uses a locking nut for axial locking and positioning after the bearing clearance is adjusted. When the spindle stops at high speed or rotates in the reverse direction, the thread of the transition plate 7 will have the risk of locking failure, resulting in a smaller bearing clearance and causing serious consequences such as spindle locking.

[0005] Therefore, it is an urgent problem for technical personnel in this field to develop a spindle assembly structure and locking method for a hemispherical bearing with a more reliable locking effect and a smaller matching error. Summary of the invention

[0006] In view of this, the present invention provides a main shaft assembly structure and locking method of a hemispherical bearing with a more reliable locking effect and a smaller matching error.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] A main shaft assembly structure of a hemispherical bearing, characterized by comprising:

[0009] Box,

[0010] A main shaft, the main shaft is arranged in the box body;

[0011] Hemisphere, the hemisphere comprises a left hemisphere and a right hemisphere; the left hemisphere and the right hemisphere are hemispherical, and a through hole is provided in the middle for the main shaft to pass through; the left hemisphere and the right hemisphere are arranged at two ends of the main shaft, and the spherical ends of the left hemisphere and the right hemisphere are arranged oppositely; the main shaft is T-shaped, and the outer end surface of the right hemisphere is fixedly connected to the T-shaped end surface of the main shaft by a first screw;

[0012] The bearing shell comprises a left bearing shell and a right bearing shell, the left bearing shell and the right bearing shell are hollow inside, and the inner side surface is spherical; the left bearing shell cover is arranged on the outer side of the left hemisphere, and the right bearing shell cover is arranged on the outer side of the right hemisphere; the left bearing shell and the right bearing shell are placed at two ends of the box body, and are fixedly connected to the box body by a second screw;

[0013] A transition piece, which is sleeved on the outer side of one end of the main shaft close to the left hemisphere and is threadedly connected to the main shaft; the transition piece is fixedly connected to the end of the left hemisphere by a third screw; a positioning retaining ring is extended on the side of the transition piece close to the left hemisphere, and a positioning groove is provided at the position of the left hemisphere corresponding to the positioning retaining ring, and the positioning retaining ring is inserted into the positioning groove; a locking block is provided at the end of the transition plate away from the left hemisphere, and the locking block is integrally connected to the transition plate, and a fourth screw for locking the axial thread of the main shaft is fixed on the surface of the locking block.

[0014] The beneficial effect of adopting the above technical solution is that the transition piece in the present invention is plugged into the positioning groove of the left hemisphere through the positioning retaining ring, so as to realize the radial positioning of the left hemisphere; the transition plate and the locking block are connected as one piece, and the axial thread of the main shaft is locked and positioned by the fourth screw. Compared with the existing separate structure of the locking nut and the transition piece, the locking structure in the present invention is more reliable, and the problem of thread locking failure can be avoided during use.

[0015] Preferably, a first annular groove is provided between the side of the locking block away from the spindle and the transition plate; a second annular groove is provided on the side of the locking block that is threadedly connected to the spindle; the fourth screw is fixed to the end of the locking block away from the left hemisphere, the fourth screw is arranged along the axial direction of the spindle, and the fourth screw connects the locking block and the transition plate. The first annular groove and the second annular groove can be squeezed when the fourth screw is locked to achieve axial locking of the spindle thread.

[0016] Preferably, the fourth screw is fixed to the side of the locking block away from the main shaft, the fourth screw is perpendicular to the axial direction of the main shaft, and the fourth screw presses against the thread surface of the main shaft. When the fourth thread is locked, it squeezes the thread of the main shaft to achieve radial locking of the main shaft thread.

[0017] A locking method for a main shaft assembly structure of a hemispherical bearing, the locking steps are as follows:

[0018] 1) Adjust the center of the right hemisphere to coincide with the axis of the spindle: fix the dial gauge seat on the outer side of the box body, and use the dial gauge to measure the radial runout of the spindle; after the right hemisphere and the spindle are installed in place, rotate the spindle and measure the radial runout of the spindle; then apply a certain preload force to the first screw, and ensure that the radial clearance of the spindle can be adjusted. At this time, tap the radial direction of the spindle and measure the radial runout value of the spindle; apply a preload force to the first screw for multiple times, measure the radial runout value of the spindle, and when the measured radial runout value of the spindle is less than 1μm, tighten the first screw. At this time, the axis of the spindle is collinear with the center of the right hemisphere;

[0019] 2) Adjust the center of the left hemisphere to coincide with the axis of the spindle: fix the dial gauge seat on the outer side of the box body, and use the dial gauge to measure the radial runout of the spindle; after the left hemisphere and the spindle are installed in place, rotate the spindle and measure the radial runout of the spindle; then apply a certain preload force to the third screw, and ensure that the radial clearance of the spindle can be adjusted, then tap the radial direction of the spindle and measure the radial runout value of the spindle; apply a preload force to the third screw for multiple times, measure the radial runout value of the spindle, and tighten the third screw until the measured radial runout value of the spindle is below 1μm. At this time, the axis of the spindle is collinear with the center of the left hemisphere; the straight line where the center of the left hemisphere and the center of the right hemisphere are located is the rotation axis, and at this time the rotation axis coincides with the axis of the spindle;

[0020] 3) Adjust the spindle axis to be perpendicular to the installation reference surface: fix the micrometer seat on the surface of the spindle, and use the micrometer to measure the end face runout of the left bearing shell; after installing the left bearing shell on the outside of the left hemisphere, rotate the spindle and measure the end face runout value of the left bearing shell; then apply a certain preload force to the second screw, and ensure that the clearance of the left bearing shell can be adjusted. At this time, tap the left bearing shell in the radial direction, measure the end face runout of the left bearing shell, and apply preload force to the second screw several times, measure the end face runout value of the left bearing shell, until the measured end face runout value of the left bearing shell is less than 1μm, tighten the second screw, at this time, the spindle axis is perpendicular to the rear installation reference surface;

[0021] 4) Repeat steps 1-3, and adjust all runout values ​​to less than 1μm, and tighten the first screw, the second screw and the third screw; at the same time, install pins at the connection between the right hemisphere and the T-shaped end face of the main shaft, the connection between the outer end face of the left hemisphere and the transition plate, and the connection between the left bearing and the box body for radial positioning, and finally tighten the fourth screw to lock the axial direction of the transition plate.

[0022] The beneficial effect of adopting the above technical solution is that, in the present invention, the center of the right hemisphere and the axis of the main shaft are first adjusted to a coincident position, and then the center of the left hemisphere and the axis of the main shaft are adjusted to a coincident position, and then the axis of the main shaft is adjusted to a position perpendicular to the installation reference surface, and finally the runout values ​​of the main shaft and the left bearing are adjusted multiple times to reach the optimal state, and the locking work can be completed, and the assembly error can be reduced from the original 10μm to 1μm, which can greatly improve the installation accuracy of subsequent motors and encoders.

[0023] It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses a spindle assembly structure and locking method for a hemispherical bearing, which has the following beneficial effects:

[0024] (1) The present invention relaxes the clearance requirements between the spindle and the left and right hemispheres to achieve adjustable precision after assembly, which reduces the processing requirements and avoids the cumulative error of assembly. The original cumulative error of 10 μm is reduced to 1 μm, which improves the installation accuracy of the subsequent motor and encoder, improves the overall precision of the spindle, and reduces the vibration of the spindle when running at high speed;

[0025] (2) The transition piece adopts an integrated axial locking structure, which is more reliable than the existing separate structure of the locking nut and the transition piece. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0027] Figure 1 A schematic diagram of the structure of the hemispherical bearing and the main shaft assembly in the prior art provided by the present invention;

[0028] Figure 2 A schematic diagram of the structure of the hemispherical bearing and the main shaft assembly provided by the present invention;

[0029] Figure 3 A flow chart of the method for assembling and locking a hemispherical bearing and a main shaft provided by the present invention;

[0030] Figure 4 A schematic diagram of the structure of the hemispherical bearing and the main shaft before the first step of assembling and adjusting the hemispherical bearing provided by the present invention;

[0031] Figure 5 A structural schematic diagram of the first step of assembling and adjusting the hemispherical bearing and the main shaft provided by the present invention;

[0032] Figure 6A schematic diagram of the structure of the hemispherical bearing and the main shaft before the second step of assembling and adjusting the hemispherical bearing provided by the present invention;

[0033] Figure 7 A schematic diagram of the structure of the hemispherical bearing and the main shaft during the second step of assembling and adjusting the hemispherical bearing provided by the present invention;

[0034] Figure 8 A schematic diagram of the structure of the hemispherical bearing and the main shaft before the third step of assembling and adjusting the hemispherical bearing provided by the present invention;

[0035] Fig. 9 A simplified structural diagram of the hemispherical bearing and the main shaft during the third step of assembling and adjusting the hemispherical bearing provided by the present invention;

[0036] Fig.10 A schematic diagram of the structure of the hemispherical bearing and the main shaft during the third step of assembling and adjusting the hemispherical bearing provided by the present invention;

[0037] Fig.11 A simplified structural diagram of the hemispherical bearing and the main shaft during the fourth step of assembling and adjusting the hemispherical bearing provided by the present invention;

[0038] Fig.12 This is a schematic structural diagram of the assembly of the hemispherical bearing and the main shaft in Example 2 provided by the present invention.

[0039] Among them, in the figure,

[0040] 1-Box;

[0041] 2-spindle;

[0042] 3-Hemisphere;

[0043] 31 - left hemisphere;

[0044] 311- positioning groove;

[0045] 32-right hemisphere;

[0046] 4- first screw;

[0047] 5-bearing shell;

[0048] 51-left bearing; 52-right bearing;

[0049] 6- second screw;

[0050] 7- Transition piece;

[0051] 71- positioning retaining ring;

[0052] 8- third screw;

[0053] 9-locking block;

[0054] 91-first annular groove; 92-second annular groove;

[0055] 10-the fourth screw; 11-the micrometer; 12-the pin. DETAILED DESCRIPTION

[0056] 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.

[0057] Embodiment 1:

[0058] The embodiment of the present invention discloses a main shaft assembly structure of a hemispherical bearing, comprising:

[0059] Box 1,

[0060] A main shaft 2, the main shaft 2 is arranged in the box body 1;

[0061] Hemisphere 3, hemisphere 3 includes a left hemisphere 31 and a right hemisphere 32; the left hemisphere 31 and the right hemisphere 32 are hemispherical, and a through hole is provided in the middle for the spindle 2 to pass through; the left hemisphere 31 and the right hemisphere 32 are arranged at two ends of the spindle 2, and the spherical ends of the left hemisphere 31 and the right hemisphere 32 are arranged opposite to each other; the spindle 2 is T-shaped, and the outer end surface of the right hemisphere 32 is fixedly connected to the T-shaped end surface of the spindle 2 by a first screw 4;

[0062] The bearing bush 5 includes a left bearing bush 51 and a right bearing bush 52. The left bearing bush 51 and the right bearing bush 52 are hollow inside and have a spherical inner surface. The left bearing bush 51 is covered on the outer side of the left hemisphere 31, and the right bearing bush 52 is covered on the outer side of the right hemisphere 32. The left bearing bush 51 and the right bearing bush 52 are placed at both ends of the box body 1 and are fixedly connected to the box body 1 by a second screw 6.

[0063] A transition piece 7 is sleeved on the outer side of one end of the main shaft 2 close to the left hemisphere 31 and is threadedly connected to the main shaft 2; the transition piece 7 is fixedly connected to the end of the left hemisphere 31 by a third screw 8; a positioning retaining ring 71 is extended from one side of the transition piece 7 close to the left hemisphere 31, and a positioning groove 311 is provided at a position corresponding to the left hemisphere 31 and the positioning retaining ring 71, and the positioning retaining ring 71 is inserted into the positioning groove 311; a locking block 9 is provided at one end of the transition plate 7 away from the left hemisphere 31, and the locking block 9 is integrally connected to the transition plate 7, and a fourth screw 10 for locking the axial thread of the main shaft 2 is fixed on the surface of the locking block 9. In the present invention, the left bearing 51 is radially positioned with the housing 1, and is axially locked by the second screw 6; the right bearing 52 is radially positioned with the housing 1, and is axially slightly pre-tightened by the second screw 6, and the radial clearance is adjustable; the spindle 2 and the end face of the right hemisphere 32 are slightly pre-tightened by the first screw 4, and the radial clearance is adjustable; the pre-installed spindle 2 and the right hemisphere 32 are passed through the right bearing 52, the housing 1, and the left bearing 51, and the left hemisphere 31 and the transition piece 7 are assembled on the spindle 2, and the end faces of the left hemisphere 31 and the transition piece 7 are slightly pre-tightened by the third screw 8, and the radial clearance is adjustable; the clearance between the left hemisphere 31 and the left bearing 5, and the clearance between the right hemisphere 32 and the right bearing 52 are adjusted by adjusting the transition piece 7, so that the clearance meets the requirements, and the spindle 2 rotates smoothly. In the present invention, the axis of rotation is represented by A, and the center of the ball is represented by B.

[0064] In order to further optimize the above technical solution, a first annular groove 91 is provided between the side of the locking block 9 away from the main shaft 2 and the transition plate 7; a second annular groove 92 is provided on the side of the locking block 9 threadedly connected to the main shaft 2; the fourth screw 10 is fixed to the end of the locking block 9 away from the left hemisphere 31, the fourth screw 10 is arranged along the axial direction of the main shaft 2, and the fourth screw 10 connects the locking block 9 and the transition plate 7.

[0065] A locking method for a main shaft assembly structure of a hemispherical bearing, the locking steps are as follows:

[0066] 1) Adjust the center of the right hemisphere 32 to coincide with the axis of the spindle 2: fix the dial gauge seat on the outer side of the box body 1, and use the dial gauge 11 to measure the radial runout of the spindle 2; after the right hemisphere 32 and the spindle 2 are installed in place, rotate the spindle 2 and measure the radial runout of the spindle 2; then apply a certain preload force to the first screw 4, and ensure that the radial clearance of the spindle 2 can be adjusted, then tap the radial direction of the spindle 2 and measure the radial runout value of the spindle 2; apply a preload force to the first screw 4 for multiple times, measure the radial runout value of the spindle 2, and tighten the first screw 4 until the measured radial runout value of the spindle 2 is less than 1 μm, and then tighten the first screw 4, at which point the axis of the spindle 2 is collinear with the center of the right hemisphere 32;

[0067] 2) Adjust the center of the left hemisphere 31 to coincide with the axis of the spindle 2: fix the micrometer seat on the outer side of the box body 1, and use the micrometer 11 to measure the radial runout of the spindle 2; after the left hemisphere 31 and the spindle 2 are installed in place, rotate the spindle 2 and measure the radial runout of the spindle 2; then apply a certain preload force to the third screw 8, and ensure that the radial clearance of the spindle 2 can be adjusted, then tap the radial direction of the spindle 2 and measure the radial runout value of the spindle 2; apply a preload force to the third screw 8 for multiple times, measure the radial runout value of the spindle 2, and tighten the third screw 8 until the measured radial runout value of the spindle 2 is below 1 μm. At this time, the axis of the spindle 2 is collinear with the center of the left hemisphere 31; the straight line where the center of the left hemisphere 31 and the center of the right hemisphere 32 are located is the rotation axis, and at this time the rotation axis coincides with the axis of the spindle 2;

[0068] 3) Adjust the spindle axis to be perpendicular to the installation reference surface: fix the micrometer seat on the surface of the spindle 2, and use the micrometer 11 to measure the end face runout of the left bearing 51; after installing the left bearing 51 on the outer side of the left hemisphere 31, rotate the spindle 2 and measure the end face runout value of the left bearing 51; then apply a certain preload force to the second screw 6, and ensure that the clearance of the left bearing 51 can be adjusted, then tap the left bearing 51 in the radial direction, measure the end face runout of the left bearing 51, and apply preload force to the second screw 6 for multiple times, measure the end face runout value of the left bearing 51, until the measured end face runout value of the left bearing 51 is below 1μm, then tighten the second screw 6, at this time, the spindle axis is perpendicular to the rear installation reference surface;

[0069] 4) Repeat steps 1-3, and adjust all runout values ​​to less than 1 μm, and tighten the first screw 4, the second screw 6 and the third screw 8; at the same time, respectively install pins 12 at the connection between the right hemisphere 32 and the T-shaped end face of the main shaft 2, the connection between the outer end face of the left hemisphere 31 and the transition plate 7, and the connection between the left bearing 51 and the housing 1 for radial positioning, and finally tighten the fourth screw 10 to lock and position the transition plate 7 in the axial direction. By installing pins 12, permanent positioning of the connection between the right hemisphere 32 and the T-shaped end face of the main shaft 2, the connection between the outer end face of the left hemisphere 31 and the transition plate 7, and the connection between the left bearing 51 and the housing 1 can be achieved.

[0070] In order to further optimize the above technical solution, in the present invention, no radial positioning is performed between the left hemisphere 31 and the left bearing 5, and between the right hemisphere 32 and the right bearing 52, and there is a gap. After assembly, the center of the left hemisphere 31 and the right hemisphere 32 are radially adjusted to be aligned with the axis of the main shaft, and axial locking is performed to position them. This can effectively improve the assembly accuracy.

[0071] Embodiment 2:

[0072] In order to further optimize the above technical solution, the fourth screw 10 is fixed to the side of the locking block 9 away from the main shaft 2, the fourth screw 10 is perpendicular to the axial direction of the main shaft 2, and the fourth screw 10 presses against the threaded surface of the main shaft 92.

[0073] The other technical solutions of this embodiment are the same as those in Embodiment 1, and will not be described in detail here.

[0074] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0075] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A spindle assembly structure of a hemispherical bearing, characterized in that: include: Box (1), A main shaft (2), wherein the main shaft (2) is inserted into the box body (1); A hemisphere (3), the hemisphere (3) comprising a left hemisphere (31) and a right hemisphere (32); the left hemisphere (31) and the right hemisphere (32) are hemispherical, and a through hole is provided in the middle for the main shaft (2) to pass through; the left hemisphere (31) and the right hemisphere (32) are arranged at two ends of the main shaft (2), and the spherical ends of the left hemisphere (31) and the right hemisphere (32) are arranged opposite to each other; the main shaft (2) is T-shaped, and the outer end surface of the right hemisphere (32) is fixedly connected to the T-shaped end surface of the main shaft (2) by a first screw (4); A bearing (5), the bearing (5) comprising a left bearing (51) and a right bearing (52), the left bearing (51) and the right bearing (52) being hollow inside and having a spherical inner surface; the left bearing (51) being covered on the outer side of the left hemisphere (31), and the right bearing (52) being covered on the outer side of the right hemisphere (32); the left bearing (51) and the right bearing (52) being placed at two ends of the box body (1), and being fixedly connected to the box body (1) by a second screw (6); A transition piece (7), wherein the transition piece (7) is sleeved on the outer side of one end of the main shaft (2) close to the left hemisphere (31) and is threadedly connected to the main shaft (2); the transition piece (7) and the end of the left hemisphere (31) are fixedly connected by a third screw (8); a positioning retaining ring (71) extends from one side of the transition piece (7) close to the left hemisphere (31), and a positioning groove (311) is provided at a position corresponding to the left hemisphere (31) and the positioning retaining ring (71), and the positioning retaining ring (71) is inserted into the positioning groove (311); a locking block (9) is provided at one end of the transition piece (7) away from the left hemisphere (31), and the locking block (9) is integrally connected to the transition piece (7), and a fourth screw (10) for locking the axial thread of the main shaft (2) is fixed on the surface of the locking block (9) A first annular groove (91) is provided between the side of the locking block (9) away from the main shaft (2) and the transition piece (7); a second annular groove (92) is provided on the side of the locking block (9) threadedly connected to the main shaft (2); The fourth screw (10) is fixed to the end of the locking block (9) away from the left hemisphere (31), the fourth screw (10) is arranged along the axial direction of the main shaft (2), and the fourth screw (10) connects the locking block (9) and the transition piece (7).

2. A locking method for a spindle assembly structure of a hemispherical bearing, the spindle assembly structure being the spindle assembly structure as claimed in claim 1, characterized in that: The locking steps are as follows: 1) Adjust the center of the right hemisphere (32) to coincide with the axis of the spindle (2): fix a micrometer seat on the outer side of the housing (1), and use a micrometer (11) to measure the radial runout of the spindle (2); after the right hemisphere (32) and the spindle (2) are installed in place, rotate the spindle (2) and measure the radial runout of the spindle (2); then apply a certain pre-tightening force to the first screw (4), and ensure that the radial clearance of the spindle (2) can be adjusted, then tap the radial direction of the spindle (2) and measure the radial runout value of the spindle (2); apply a pre-tightening force to the first screw (4) for multiple times, measure the radial runout value of the spindle (2), and when the measured radial runout value of the spindle (2) is less than 1 μm, tighten the first screw (4), and at this time, the axis of the spindle (2) is collinear with the center of the right hemisphere (32); 2) Adjust the center of the left hemisphere (31) to coincide with the axis of the spindle (2): fix a dial gauge seat on the outer side of the housing (1), and use a dial gauge (11) to measure the radial runout of the spindle (2); after the left hemisphere (31) and the spindle (2) are installed in place, rotate the spindle (2) and measure the radial runout of the spindle (2); then apply a certain preload force to the third screw (8), and ensure that the radial clearance of the spindle (2) can be adjusted, and then tap the spindle (2) In radial direction, the radial runout value of the main shaft (2) is measured; a pre-tightening force is applied to the third screw (8) for multiple times, and the radial runout value of the main shaft (2) is measured until the measured radial runout value of the main shaft (2) is less than 1 μm, and the third screw (8) is tightened. At this time, the axis of the main shaft (2) is collinear with the center of the left hemisphere (31); the straight line where the center of the left hemisphere (31) and the center of the right hemisphere (32) are located is the rotation axis, and at this time, the rotation axis coincides with the axis of the main shaft (2); 3) Adjust the spindle axis to be perpendicular to the installation reference surface: fix the micrometer seat on the surface of the spindle (2), and use the micrometer (11) to measure the end face runout of the left bearing (51); after installing the left bearing (51) on the outer side of the left hemisphere (31), rotate the spindle (2) and measure the end face runout value of the left bearing (51); then apply a certain preload force to the second screw (6), and ensure that the clearance of the left bearing (51) can be adjusted, then tap the left bearing (51) in the radial direction, measure the end face runout of the left bearing (51), and apply preload force to the second screw (6) for multiple times, measure the end face runout value of the left bearing (51), until the measured end face runout value of the left bearing (51) is less than 1μm, tighten the second screw (6), and at this time, the spindle axis is perpendicular to the rear installation reference surface; 4) Repeat steps 1)-3) and adjust all the runout values ​​measured in steps 1)-3) to less than 1 μm, and tighten the first screw (4), the second screw (6) and the third screw (8); at the same time, pins (12) are respectively provided at the connection between the right hemisphere (32) and the T-shaped end face of the main shaft (2), the connection between the outer end face of the left hemisphere (31) and the transition piece (7), and the connection between the left bearing (51) and the housing (1) for radial positioning, and finally tighten the fourth screw (10) to lock and position the transition piece (7) in the axial direction.

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