Electrospindle

Abstract

The application relates to an electric spindle, which comprises a shell defining a mounting cavity, a rotating shaft arranged in the mounting cavity, two groups of bearing assemblies arranged on the rotating shaft, an adjusting mechanism arranged on the rotating shaft, the adjusting mechanism being located on the side of one group of bearing assemblies away from the other group of bearing assemblies, the adjusting mechanism comprising a spacer ring body and a movable moving piece arranged on the spacer ring body, the moving piece being capable of abutting on the inner ring of the bearing assembly and pushing the inner ring to move, and / or at least one group of bearing assemblies being sleeved with a positioning sleeve, the positioning sleeve being provided with a pushing piece, the pushing piece being capable of moving in the radial direction of the rotating shaft to push the bearing assembly. According to the electric spindle, the cooperation between the bearing assembly and the rotating shaft can be adjusted, the behavior tolerance exception of the cooperation surface of the rotating shaft and the bearing assembly can be solved, the precision of the bearing assembly can be adjusted, the optimization of the rotating precision of the whole electric spindle is realized on the basis of reducing the precision of the bearing assembly itself, and the machining cost of the parts of the electric spindle is saved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric spindles, in particular to an electric spindle. BACKGROUND

[0002] The electric spindle has a transmission structure mode of combining the built-in motor and the machine tool spindle into one, which can better adapt to high speed and high precision rotation, and has small vibration, thereby meeting the actual needs of precision machining and high speed cutting of mold numerical control machine tools.

[0003] In actual part machining, the electric spindle needs a broach mechanism to clamp the tool for high speed rotation, and the round runout of the tool plays an important role in the machining precision of the machine tool spindle. The round runout of the tool in the industry reflects the good or bad of the precision of the whole spindle, which is finally reflected in the detection rod precision. However, the high precision runout of the whole spindle has extremely strict requirements on the assembly workers of the spindle and the tolerance grade of the parts, and it is usually difficult to achieve the required geometric precision.

[0004] Patent application No. 202111078072.4 discloses a gap adjustable magnetic suspension electric spindle. The structure is designed with a taper at the rotating shaft, which cooperates with the inner taper hole of the magnetic bearing to make the radial gap adjustable and stable. This structure has requirements for the bearing itself, increases the matching difficulty of the bearing and the shaft core, and is not replaceable.

[0005] Patent application No. 201710079281.8 is a precise oil and gas lubricated electric spindle structure. The bearing end face of the electric spindle structure is directly fixed with a nut, and no coaxial adjustment structure is arranged outside the rear bearing seat. This makes it difficult to assemble the electric spindle machine, and it is not easy to adjust. SUMMARY

[0006] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application provides an electric spindle which can adjust the coaxiality of the bearing assembly and the rotating shaft, and improve the rotating precision of the electric spindle machine.

[0007] The electric spindle according to the present application comprises: a housing defining an installation cavity; a rotating shaft arranged in the installation cavity, the rotating shaft being sleeved with two groups of bearing assemblies; at least one adjusting mechanism, the adjusting mechanism being sleeved on the rotating shaft, the adjusting mechanism being located on the side of one group of bearing assemblies away from the other group of bearing assemblies, the adjusting mechanism comprising a spacer ring body and a movable member arranged on the spacer ring body, the movable member being capable of abutting on the inner ring of the bearing assembly and pushing the inner ring to displace at least in the radial direction of the rotating shaft, and / or at least one group of bearing assemblies being sleeved with a positioning sleeve, the positioning sleeve being provided with a pushing member, the pushing member being movable in the radial direction of the rotating shaft to push the bearing assembly.

[0008] According to the electric spindle, the movable piece can adjust the cooperation between the inner ring of the bearing assembly and the rotating shaft, solve the behavior tolerance exception of the cooperation surface of the rotating shaft and the bearing assembly, adjust the precision of the bearing assembly, the pushing piece can adjust the precision of the rotating shaft itself, and the precision of the whole electric spindle can be adjusted, so that the precision of the whole electric spindle is optimized on the basis of reducing the precision of the bearing assembly, and the machining cost of the parts of the electric spindle is saved.

[0009] According to the electric spindle, the movable piece can adjust the cooperation between the inner ring of the bearing assembly and the rotating shaft, solve the behavior tolerance exception of the cooperation surface of the rotating shaft and the bearing assembly, adjust the precision of the bearing assembly, the pushing piece can adjust the precision of the rotating shaft itself, and the precision of the whole electric spindle can be adjusted, so that the precision of the whole electric spindle is optimized on the basis of reducing the precision of the bearing assembly, and the machining cost of the parts of the electric spindle is saved.

[0010] Optionally, the center axis of the assembly hole is inclined towards a direction gradually away from the center axis of the spacer ring body in a direction gradually away from the bearing assembly.

[0011] Optionally, the movable piece comprises a threaded portion and a pin shaft arranged in sequence along the direction of the center axis of the assembly hole, and the pin shaft is arranged between the threaded portion and the bearing assembly.

[0012] Optionally, the pin shaft is made of copper or copper alloy.

[0013] Optionally, the spacer ring body is provided with a positioning surface, the positioning surface connects the outer peripheral wall of the spacer ring body and the end wall opposite in the axial direction, one end of the assembly hole away from the bearing assembly penetrates the positioning surface, and the center axis of the assembly hole is perpendicular to the positioning surface.

[0014] Optionally, a first limiting portion is arranged in the assembly hole, a second limiting portion is arranged on the pin shaft, and the first limiting portion and the second limiting portion are movably matched.

[0015] Optionally, one end of the shell is provided with an end cover, the two groups of bearing assemblies comprise a first bearing assembly and a second bearing assembly, the first bearing assembly is arranged between the end cover and the second bearing assembly, the shell, the end cover and the first bearing assembly jointly define a first accommodating cavity, the spacer ring body is located in the first accommodating cavity, the outer peripheral wall of the spacer ring body is spaced from the inner peripheral wall of the first accommodating cavity, and the end cover and the shell further define a second accommodating cavity, the second accommodating cavity is communicated with the first accommodating cavity, and a detachable sealing ring is arranged in the second accommodating cavity.

[0016] Optionally, a straight line where the center axis of the assembly hole is located penetrates the second accommodating cavity.

[0017] Optionally, the second bearing assembly is sleeved with a positioning sleeve, a jackscrew hole is arranged on the positioning sleeve, the pushing piece is arranged in the jackscrew hole, and the pushing piece is configured as a jackscrew.

[0018] Optionally, the positioning sleeve is provided with at least four jackscrew holes, the jackscrew holes are uniformly distributed along the circumference of the positioning sleeve, and the jackscrew and the jackscrew hole are one-to-one corresponding. BRIEF DESCRIPTION OF DRAWINGS

[0019] The accompanying drawings, which are incorporated herein and constitute part of the specification, illustrate embodiments consistent with the application and, together with the description, serve to explain the principles of the application.

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced here. Obviously, for those skilled in the art, other drawings can also be obtained based on these drawings without any creative effort.

[0021] Figure 1 is a sectional view of an electric spindle according to an embodiment of the present application;

[0022] Figure 2 is Figure 1 is an enlarged view of A in FIG. 5;

[0023] Figure 3 is a perspective view of a spacer body of an electric spindle according to an embodiment of the present application;

[0024] Figure 4 is a sectional view of an adjustment mechanism of an electric spindle according to an embodiment of the present application;

[0025] Figure 5 is a sectional view of a positioning sleeve of an electric spindle according to an embodiment of the present application.

[0026] REFERENCE SIGNS:

[0027] Electric spindle 1, housing 10, first accommodating cavity 11, second accommodating cavity 12, rotating shaft 20, first spacer 21, second spacer 22, central axis 23 of rotating shaft 20, bearing assembly 30, first bearing assembly 31, first bearing seat 311, first sub-bearing 312, inner ring 3122, central axis 3123 of inner ring 3122, second sub-bearing 313, second bearing assembly 32, second bearing seat 321, third sub-bearing 322, adjustment mechanism 40, spacer body 41, assembly hole 412, movable piece 42, threaded part 422, pin shaft 424, positioning surface 43, positioning sleeve 50, jackscrew hole 51, end cover 60, locking nut 70, flange plate 80, sealing ring 90. DETAILED DESCRIPTION

[0028] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application.

[0029] As shown in FIGS. 1 and 2, the electric spindle 1 according to the embodiments of the present application comprises a housing 10, a rotating shaft 20 and bearing assemblies 30. Figure 1 Figure 2 As shown in FIGS. 1 and 2, the electric spindle 1 according to the embodiments of the present application comprises a housing 10, a rotating shaft 20 and bearing assemblies 30.

[0030] Specifically, the housing 10 defines a mounting cavity; the rotating shaft 20 is arranged in the mounting cavity, and two groups of bearing assemblies 30 are arranged on the rotating shaft 20. At least one adjusting mechanism 40 is arranged on the rotating shaft 20, the adjusting mechanism 40 is located on the side of one group of bearing assemblies 30 away from the other group of bearing assemblies 30, the adjusting mechanism 40 comprises a spacer body 41 and a movable member 42 arranged on the spacer body 41, the movable member 42 can abut on and push the inner ring 3122 of the bearing assembly 30 to produce displacement at least in the radial direction of the rotating shaft 20, and / or at least one group of bearing assemblies 30 is provided with a positioning sleeve 50, the positioning sleeve 50 is provided with a pushing member, the pushing member is movable along the radial direction of the rotating shaft 20 to push the bearing assembly 30.

[0031] That is, in some embodiments, the rotating shaft 20 of the electric spindle 1 is provided with the adjusting mechanism 40; in some embodiments, at least one group of bearing assemblies 30 is provided with the positioning sleeve 50, the positioning sleeve 50 is provided with the pushing member; in some embodiments, the rotating shaft 20 of the electric spindle 1 is provided with the adjusting mechanism 40, and at least one group of bearing assemblies 30 is provided with the positioning sleeve 50, the positioning sleeve 50 is provided with the pushing member.

[0032] Wherein, “at least one adjusting mechanism 40 is arranged on the rotating shaft 20” means that one adjusting mechanism 40 can be arranged on the rotating shaft 20, the adjusting mechanism 40 is located on the side of one group of bearing assemblies 30 away from the other group of bearing assemblies 30, or two adjusting mechanisms 40 can be arranged on the rotating shaft 20, the two adjusting mechanisms 40 are respectively located on the sides of two groups of bearing assemblies 30 away from each other.

[0033] ​In detail, since the rotating shaft 20 directly cooperates with the inner ring 3122 of the bearing assembly 30 during rotation, the inner ring 3122 of the bearing assembly 30 directly affects the rotation accuracy of the rotating shaft 20. The movable piece 42 of the adjusting mechanism 40 can abut against the inner ring 3122 of the bearing assembly 30 and push the inner ring 3122 to move, so as to finely adjust the inner ring 3122 of the bearing assembly 30. The position of the inner ring 3122 subjected to the force is displaced relative to the position of the inner ring 3122 not subjected to the force, so as to be inclined, so that the inner ring 3122 as a whole has a displacement component in the radial direction, so that the central axis 3123 of the inner ring 3122 of the bearing assembly 30 can coincide with the central axis 23 of the rotating shaft 20, so as to realize the accuracy adjustment of the cooperation between the bearing assembly 30 and the rotating shaft 20, so that the runout value of the rotating shaft 20 relative to the support part is optimized. In the test detection of some embodiments, the distal end runout of the tool shank of the motorized spindle 1 under the clamping of the broach system is less than 0.001 mm. The pushing piece can move in the radial direction of the rotating shaft 20 to push the bearing assembly 30, so as to adjust the coaxiality of the two groups of bearing assemblies 30 and the rotating shaft 20, eliminate the influence of the size chain accumulation and machining error of the assembly of the bearing assembly 30 and the rotating shaft 20, and make the central axis of the bearing assembly 30 coincide with the central axis 23 of the rotating shaft 20 as much as possible, so as to avoid the influence of poor static support of the rotating shaft 20 on the overall accuracy of the rotating shaft 20 and the motorized spindle 1.

[0034] It should be noted that, in actual production and application, the at least one group of bearing assemblies 30 includes two bearings, and the adjusting mechanism 40 abuts against one of the bearings (a first sub-bearing 312), as shown in Figure 1 .

[0035] According to the motorized spindle 1 of the embodiment of the present application, the movable piece 42 can adjust the cooperation between the inner ring 3122 of the bearing assembly 30 and the rotating shaft 20, solve the behavior tolerance abnormality of the cooperation surface of the rotating shaft 20 and the bearing assembly 30, adjust the accuracy of the bearing assembly 30, and the pushing piece can adjust the accuracy of the rotating shaft 20 itself, so as to realize the adjustment of the overall accuracy of the motorized spindle 1, so as to realize the optimization of the overall rotation accuracy of the motorized spindle 1 on the basis of reducing the accuracy of the bearing assembly 30 itself, and save the machining cost of the parts of the motorized spindle 1.

[0036] As shown in Figure 3 and Figure 4As shown, in the electric spindle 1 according to an embodiment of the present invention, the spacer body 41 is provided with a mounting hole 412, and the movable part 42 is engaged in the mounting hole 412. The angle between the central axis of the mounting hole 412 and the central axis of the spacer body 41 is α, where α satisfies 0° < α ≦ 30°. For example, α can be 2°, 4°, 6°, 8°, 10°, 12°, 14°, 16°, 18°, 20°, 22°, 24°, 26°, 28°, and 30°, etc. A suitable α can ensure a suitable contact area between the movable part 42 and the inner ring 3122 of the bearing assembly 30 when the movable part 42 contacts the bearing assembly 30, thereby optimizing the adjustment range of the bearing assembly 30 relative to the rotating shaft 20.

[0037] like Figure 3 As shown, in some embodiments, the number of mounting holes 412 is at least four, and the at least four mounting holes 412 are evenly distributed along the circumference of the spacer body 41. This allows for adjustment of the inner ring 3122 of the bearing assembly 30 from multiple directions, further optimizing the adjustment range of the bearing assembly 30 relative to the rotating shaft 20. In one embodiment of this application, 16 mounting holes 412 are evenly distributed along the circumference of the spacer body 41, forming 16 equal parts. The included angle between the central axes of any two adjacent mounting holes 412 is 22.5 degrees, meaning that the inner ring 3122 of the bearing assembly 30 can be adjusted regardless of the angle. Experimental verification has shown that this further improves the precision adjustment range of the bearing assembly 30 and greatly increases the probability that the central axis 3123 of the inner ring 3122 of the bearing assembly 30 coincides with the central axis 23 of the rotating shaft 20.

[0038] In some embodiments, the central axis of the mounting hole 412 is inclined in a direction that gradually moves away from the bearing assembly 30, towards a direction that gradually moves away from the central axis of the spacer body 41. This facilitates the adjustment of the moving part 42 with tools such as a wrench after the electric spindle 1 is assembled, thereby adjusting the position of the inner ring 3122 of the bearing assembly 30, simplifying the overall structural setup of the electric spindle 1 and improving operational convenience.

[0039] like Figure 2 and Figure 4As shown, in some embodiments, the movable element 42 comprises a threaded portion 422 and a pin shaft 424 arranged in sequence along the central axis of the assembly hole 412, the pin shaft 424 is arranged between the threaded portion 422 and the bearing assembly 30, the pin shaft 424 is pushed by rotating the threaded portion 422, which can drive the inner ring 3122 of the bearing assembly 30 to be pushed, since the rotation of the threaded portion 422 can be accurately controlled, it can prevent the inner ring 3122 from being pushed too much due to improper control force, and compared with the threaded portion 422 directly pushing the inner ring 3122, since the contact end face between the pin shaft 424 and the inner ring 3122 is not provided with a tooth shape like the threaded portion 422, the contact area between the pin shaft 424 and the inner ring 3122 will be larger, which can further optimize the adjustment range of the bearing assembly 30 relative to the rotating shaft 20. Generally, the threaded portion 422 can be various types of screws and bolts, etc.

[0040] In some embodiments, the pin shaft 424 is made of copper or copper alloy, so that the hardness of the pin shaft 424 is less than the hardness of the inner ring 3122 of the bearing assembly 30, which can play a protective role for the bearing assembly 30 during the adjustment force on the inner ring 3122.

[0041] As shown, Figure 4 In some embodiments, the spacer ring body 41 is provided with a positioning surface 43, the positioning surface 43 connects the outer peripheral wall of the spacer ring body 41 and the opposite end wall in the axial direction, one end of the assembly hole 412 away from the bearing assembly 30 penetrates the positioning surface 43, and the central axis of the assembly hole 412 is perpendicular to the positioning surface 43. Since the central axis of the assembly hole 412 and the central axis of the spacer ring body 41 are at a certain angle, it is not easy to position during processing, and processing errors are easy to occur. Therefore, when the spacer ring is processed, the assembly hole 412 can be positioned by first processing the positioning surface 43 and then processing the assembly hole 412, which can improve the processing precision of the assembly hole 412, and further improve the processing precision of the adjusting mechanism 40 itself.

[0042] In some embodiments, the assembly hole 412 is provided with a first limiting portion, and the pin shaft 424 is provided with a second limiting portion, the first limiting portion and the second limiting portion are movably matched, through the cooperation of the first limiting portion and the second limiting portion, the pin shaft 424 can be guided and limited, which can prevent the pin shaft 424 from rotating during the process of pushing the pin shaft 424 by the threaded portion 422, and can also prevent the pin shaft 424 from being pulled out of the assembly hole 412 when the adjusting mechanism 40 is not assembled on the rotating shaft 20. Alternatively, the pin shaft 424 and the assembly hole 412 can be zero-gap matched (within a certain error range), and the pin shaft 424 can be prevented from being pulled out without the first limiting portion and the second limiting portion, which is not limited by the present application, but only provides a possible way.

[0043] As shown, Figure 1 and Figure 2As shown, in some embodiments, one end of the shell 10 is provided with an end cover 60, the two groups of bearing assemblies 30 include a first bearing assembly 31 and a second bearing assembly 32, the first bearing assembly 31 is arranged between the end cover 60 and the second bearing assembly 32, the shell 10, the end cover 60 and the first bearing assembly 31 jointly define a first accommodating cavity 11, the spacer ring body 41 is located in the first accommodating cavity 11, the outer peripheral wall of the spacer ring body 41 is spaced from the inner peripheral wall of the first accommodating cavity 11, and the end cover 60 and the shell 10 further define a second accommodating cavity 12, the second accommodating cavity 12 is communicated with the first accommodating cavity 11, and a detachable sealing ring 90 is arranged in the second accommodating cavity 12. In this way, after the assembly of each part of the electric spindle 1 is completed, the sealing ring 90 can be removed, a tool such as a wrench can be inserted into the first accommodating cavity 11 to adjust the movable part 42, so as to adjust the inner ring 3122 of the bearing assembly 30, and after the adjustment is completed, the sealing ring 90 can be reassembled, so as to prevent foreign matters from entering the first accommodating cavity 11 and prevent the lubricating liquid in the first accommodating cavity 11 from leaking, so that the electric spindle 1 can adapt to working conditions containing a large amount of dust, water mist, cutting fluid and cutting impurities, and has the characteristics of good dustproof performance, long service life of the bearing assembly 30 and good stability.

[0044] As shown, Figure 1 As shown, the first bearing assembly 31 includes a first bearing seat 311, a first sub-bearing 312 and a second sub-bearing 313, the first sub-bearing 312 and the second sub-bearing 313 are provided with a first spacer ring 21 and a second spacer ring 22, the first spacer ring 21 is sleeved outside the rotating shaft 20, the second spacer ring 22 is sleeved outside the first spacer ring 21, and the rotating shaft 20 is further provided with a locking nut 70, the locking nut 70 is threadedly connected with the rotating shaft 20, the locking nut 70 makes the adjusting mechanism 40 abut against the first sub-bearing 312, and the side of the first bearing seat 311 facing the end cover 60 is further provided with a flange plate 80, the flange plate 80 is sleeved outside the rotating shaft 20 and fixed to the shell 10, and the second bearing assembly 32 includes a second bearing seat 321 and a third sub-bearing 322, the second bearing seat 321 is sleeved with a positioning sleeve 50, and the pushing piece on the positioning sleeve 50 can directly push the second bearing seat 321. In this way, the first bearing assembly 31 can be finely adjusted by the adjusting mechanism 40, and the second bearing assembly 32 and the rotating shaft 20 can be coarsely adjusted by the pushing piece, and the adjustment of the rotating shaft 20 is equivalent to the adjustment of the first bearing assembly 31 sleeved thereon. Since the first bearing assembly 31 is closer to the tool holder, it has a greater influence on the circular runout of the tool, and therefore the fine adjustment of the first bearing assembly 31 needs to be combined with the coarse adjustment of the first bearing assembly 31, the second bearing assembly 32 and the rotating shaft 20 by the pushing piece, so that the overall precision of the electric spindle 1 is higher.

[0045] In some embodiments, a straight line where the center axis of the assembly hole 412 is located passes through the second accommodating cavity 12, so that the position of the assembly hole 412 can be conveniently observed by the human eye and the movable part 42 is adjusted by using a wrench or the like tool.

[0046] As shown in Figure 1 and Figure 5 In some embodiments, the second bearing assembly 32 is sleeved with a positioning sleeve 50, the positioning sleeve 50 is provided with a jackscrew hole 51, a jacking piece is arranged in the jackscrew hole 51, and the jacking piece is configured as a jackscrew. The jacking piece can adjust and position the bearing assembly 30 and the rotating shaft 20, the adjustment range of the center axis 23 of the bearing assembly 30 and the rotating shaft 20 is large, one of the bearing assembly 30 and the rotating shaft 20 can be directly adjusted, the adjustment of the rotating shaft 20 indirectly adjusts the other bearing assembly 30 and the rotating shaft 20, the assembly precision of the two groups of bearing assemblies 30 and the rotating shaft 20 is coarsely adjusted, the precision adjustment time of the motorized spindle 1 is shortened, the rotating shaft 20 can be adjusted during the assembly process of the motorized spindle 1, and the relative movement of the positioning sleeve 50 and the bearing assembly 30 is prevented. The jacking piece is configured as a jackscrew, the structure is various, and the universality and interchangeability are good.

[0047] As shown in Figure 5 In some embodiments, the positioning sleeve 50 is provided with at least four jackscrew holes 51, the jackscrew holes 51 are uniformly distributed along the circumference of the positioning sleeve 50, and the jacking piece corresponds to the jackscrew hole 51 one by one. In this way, the bearing assembly 30 and the rotating shaft 20 can be adjusted from multiple directions, and the precision adjustment range of the bearing assembly 30 and the rotating shaft 20 is further optimized. For example, the number of jackscrew holes 51 can be four, six, eight, ten, twelve, fourteen and sixteen, and the like, which is not limited in the application.

[0048] In the description of the application, it should be understood that the terms “upper”, “lower”, “left”, “right”, “inner”, “outer”, “axial”, “radial”, “circumferential” and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application. In addition, the features defined as “first” and “second” can be explicitly or implicitly included one or more features. In the description of the application, unless otherwise specified, the meaning of “a plurality of” is two or more.

[0049] In the description of the application, it is necessary to point out that, unless otherwise clearly specified and limited, the terms "mounting", "connection", "linking" should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through intermediate medium, can be internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0050] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "illustrative embodiment", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

Claims

1. An electric spindle for clamping a tool by a drawbar mechanism, characterized in that, The electric spindle comprises: a housing defining a mounting cavity; a rotating shaft arranged in the mounting cavity, a first bearing assembly and a second bearing assembly being sleeved on the rotating shaft, the first bearing assembly being closer to a shank of the tool than the second bearing assembly; at least one adjusting mechanism sleeved on the rotating shaft, the adjusting mechanism being located on a side of the first bearing assembly away from the second bearing assembly, the adjusting mechanism comprising a spacer body and a movable member arranged on the spacer body, the movable member being capable of abutting on an inner ring of the bearing assembly and pushing the inner ring to be displaced at least in a radial direction of the rotating shaft, the second bearing assembly being sleeved with a positioning sleeve, the positioning sleeve being provided with a pushing member, the pushing member being movable in the radial direction of the rotating shaft to push the second bearing assembly.

2. The electric spindle according to claim 1, characterized in that, the spacer body is provided with assembly holes, the movable member is clamped in the assembly holes, an included angle between a central axis of the assembly hole and a central axis of the spacer body is a, a satisfies 0° < a ≤ 30°, and / or the number of the assembly holes is at least four, and the at least four assembly holes are uniformly distributed along a circumferential direction of the spacer body.

3. The electric spindle according to claim 2, characterized in that, In a direction gradually away from the first bearing assembly, the central axis of the assembly hole is inclined towards a direction gradually away from the central axis of the spacer body.

4. The electric spindle according to claim 2, characterized in that, the movable member comprises a threaded portion and a pin shaft arranged in sequence along the central axis of the assembly hole, the pin shaft being arranged between the threaded portion and the first bearing assembly.

5. The electric spindle according to claim 4, characterized in that, The pin shaft is made of copper or copper alloy.

6. The electric spindle according to any of claims 2-5, characterized in that, The spacer body is provided with a positioning surface, the positioning surface being connected with an outer peripheral wall and an end wall opposite in an axial direction of the spacer body, an end of the assembly hole away from the first bearing assembly penetrating through the positioning surface, and the central axis of the assembly hole being perpendicular to the positioning surface.

7. The electric spindle according to claim 4, characterized in that, The assembly hole is provided with a first limiting portion, the pin shaft is provided with a second limiting portion, and the first limiting portion and the second limiting portion are movably matched.

8. The electric spindle according to claim 4, characterized in that, One end of the housing is provided with an end cover, the first bearing assembly is arranged between the end cover and the second bearing assembly, the housing, the end cover and the first bearing assembly jointly define a first accommodating cavity, the spacer body is located in the first accommodating cavity, an outer peripheral wall of the spacer body is spaced from an inner peripheral wall of the first accommodating cavity, the end cover and the housing further define a second accommodating cavity, the second accommodating cavity is communicated with the first accommodating cavity, and a detachable sealing ring is arranged in the second accommodating cavity.

9. The electric spindle according to claim 8, characterized in that, A straight line where the central axis of the assembly hole is located penetrates through the second accommodating cavity.

10. The electric spindle according to claim 8, characterized in that, The second bearing assembly is sleeved with the positioning sleeve, the positioning sleeve is provided with a tapping hole, the pushing member is arranged in the tapping hole, and the pushing member is configured as a tapping screw.

11. The electric spindle according to claim 10, characterized in that, The positioning sleeve is provided with at least four tapping holes, the tapping holes are uniformly distributed along a circumferential direction of the positioning sleeve, and the pushing member corresponds to the tapping hole in one-to-one correspondence.

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