An electric machining spindle based on direct drive structure

Abstract

The present invention provides an electric machining spindle based on a direct-drive structure, comprising a motor and: an adapter mechanism: an inner adapter plate fixed to the motor, an outer adapter plate connected to the motor housing; an insulation mechanism: a rigid inner insulation plate fixed to the end face of the inner adapter plate, and an outer insulation plate fixed to the outer adapter plate; a conductive mechanism: a conductive shaft fixed to the end face of the inner insulation plate, a conductive seat fixed to the end face of the outer insulation plate, and a carbon brush provided on the conductive seat to draw electricity to the conductive shaft; a flushing mechanism: a structural shaft fixed to the end face of the conductive shaft, a structural seat fixed to the end face of the conductive seat, and a central flushing channel and a peripheral gas channel axially provided on the structural shaft; an annular groove provided on the inner circumferential wall of the structural seat, corresponding to the channel opening on the structural shaft, and connected to the inlet on the outer circumferential wall of the structural seat; a sealing structure sealing the channel between the structural shaft and the structural seat; and a clamp: a clamp seat fixed to the end face of the structural shaft, with clamping jaws elastically fixed to the clamp seat, and the clamp seat provided with a central flushing channel and a clamping jaw gas channel. This electric spindle can achieve high torque and high precision.

Description

Technical Field

[0001] The present invention relates to the technical field of electric machining, and in particular to an electric machining spindle based on a direct drive structure. Background Art

[0002] With the rapid development of science and technology, the requirements for the motion accuracy and speed of CNC equipment are becoming increasingly stringent. Because electrodes or workpieces require precise indexing or feeding, motors must not only provide sufficient rotational torque and load capacity but also overcome the effects of rotational inertia to achieve high positioning accuracy and repeatability. In the specialized EDM micromachining process, spindle positioning accuracy must reach micrometers. Therefore, while maintaining machining accuracy, the spindle must also have a high response speed to support the slow feed and precise positioning control required for EDM machining. To achieve this, a low-inertia servo system must be designed for the spindle to minimize motion delays introduced by the drive system.

[0003] Due to the system's own rotational inertia and gravity, the driving force of the EDM machine's spindle components rotates perpendicular to the direction of gravity. As the spindle rotates, its positioning accuracy and repeatability are affected by the combined effects of the system's own rotational inertia and gravity. Failure to take appropriate measures to control gravity will not only affect the smooth operation of the system but also cause inertial shock to the machine tool, thereby reducing the accuracy of the servo system.

[0004] Traditional servo systems use AC servo motors for both drive and positioning. However, this structure not only requires a large space, but also suffers from a non-rigid connection between the spindle's moving components and the drive. This results in significant rotational accuracy errors and motion shock when the spindle switches forward and backward, resulting in relatively low accuracy. Summary of the Invention

[0005] The purpose of the present invention is to improve the deficiencies of the prior art and to provide an electric machining spindle based on a direct drive structure that can achieve high torque and high precision.

[0006] The object of the present invention is achieved like this:

[0007] An electric machining spindle based on a direct drive structure includes a motor, a switching mechanism, an insulating mechanism, a conductive mechanism, a flushing mechanism, a sealing structure and a clamp.

[0008] The adapter mechanism includes an inner adapter plate and an outer adapter plate, wherein the inner adapter plate is fixed to the end face of the output shaft of the motor, and the outer adapter plate is connected to the motor housing, and the motor is built into a chamber formed by the inner and outer adapter plates;

[0009] The insulating mechanism includes a rigid inner insulating plate and an outer insulating plate, wherein the inner insulating plate is fixed to the end surface of the inner adapter plate, and the outer insulating plate is fixed to the outer adapter plate and surrounds the outer periphery of the inner insulating plate;

[0010] The conductive mechanism includes a conductive shaft and a conductive seat. The conductive shaft is fixed to the end surface of the inner insulating plate, and the conductive seat is fixed to the end surface of the outer insulating plate. The conductive seat surrounds the outer circumference of the conductive shaft. A plurality of carbon brush mounting holes are circumferentially provided on the conductive seat. Carbon brushes are elastically arranged radially in the holes so that the carbon brushes are pressed against the conductive shaft and conduct electricity to the conductive shaft.

[0011] The flushing mechanism includes a structural shaft and a structural seat, the structural shaft being fixed on the end surface of the conductive shaft, the structural seat being fixed on the end surface of the conductive seat, surrounding the outer circumference of the structural shaft, and a central flushing channel and a surrounding gas channel being axially provided on the structural shaft, a liquid inlet and an air inlet being provided on the outer circumferential surface of the structural shaft, the liquid inlet being connected to the flushing channel, and the air inlet being connected to the gas channel; a plurality of annular grooves are provided on the inner circumferential wall of the structural seat corresponding to the liquid inlet and the air inlet on the structural shaft, a through-hole is provided at the bottom of each of the annular grooves on the structural seat, the annular grooves and the through-holes constitute the structural seat flushing channel and the structural seat gas channel, so that an inlet corresponding to the liquid inlet and the air inlet on the structural shaft is opened on the outer circumferential wall of the structural seat, and when in use, a hydraulic oil pipe and a compressed gas pipe are respectively connected to the inlet;

[0012] The sealing structure is a plurality of sealing rings, which are sleeved on the edges of the grooves on both sides of each of the annular grooves on the structural shaft, so that the liquid inlet and the gas inlet of the structural seat flushing channel and the structural seat gas channel are sealed at the connection between the groove of the flushing channel and the gas channel provided on the structural shaft;

[0013] The clamp includes a clamp seat and a clamping jaw. The clamp seat is fixed on the end face of the structural shaft. The clamping jaw can be elastically reset and fixed on the clamp seat. A central flushing channel is provided on the clamp seat and is connected to the flushing channel on the structural shaft. A clamping jaw gas channel is provided on the spring structure of each clamping jaw and is connected to the gas channel on the structural shaft.

[0014] The output shaft of the motor and the inner adapter plate in the adapter mechanism, the inner insulating plate in the insulating mechanism, the conductive shaft in the conductive mechanism, the structural shaft in the flushing mechanism and the clamp are coaxially arranged.

[0015] Preferably, the motor is a torque motor.

[0016] More preferably, the torque motor is provided with a 24-bit rotary encoder to complete the positioning and repeated positioning of the electric spindle.

[0017] Preferably, the end face precision of each rotating component connected to the motor shaft and having a fixed end face is as follows: the form and position tolerance of each end face is: the total end face runout is 3-5 microns.

[0018] More preferably, from the engagement of the inner adapter plate with the end face of the motor shaft to the engagement of the fixture seat with the end face of the structural shaft, the form and position tolerance of the latter is greater than the form and position tolerance of the former.

[0019] Preferably, the motor and the outer adapter plate, i.e., the motor mounting seat, are fitted with a small gap, i.e., the gap is 8-12 microns.

[0020] Preferably, the hardness of the connecting end surfaces of the inner adapter plate, the conductive shaft, the structural shaft and the fixture seat in the fixture is 40HRC-50HRC.

[0021] Preferably, the inner insulation board is made of marble.

[0022] Preferably, the inner insulating plate of the rotating part and the outer insulating plate of the fixing seat in the insulating mechanism are of the same height, thereby improving the structural rigidity and insulation reliability.

[0023] Preferably, the plurality of carbon brushes in the conductive mechanism are symmetrically arranged on the circumference of the conductive shaft relative to the axis of the electric spindle. The carbon brushes are symmetrically arranged relative to the axis.

[0024] Preferably, the plurality of gas channels in the flushing mechanism are arranged symmetrically with respect to the axis of the electric spindle.

[0025] Preferably, the conductive shaft and the structural shaft are made of 40cr steel and are subjected to surface tempering heat treatment, wherein the quenching is performed by oil quenching at 830-860°C, so that the hardness, especially the end face hardness, reaches 40-50HRC.

[0026] Preferably, at least one of the outer adapter plate, outer insulating plate, conductive seat and structural seat is made of an aluminum alloy structural member to reduce the weight of the components.

[0027] Preferably, a symmetrical hollow structure is provided inside at least one of the inner adapter plate, the inner insulating plate, the conductive shaft and the structural shaft, so as to reduce the overall rotational inertia of the entire electric spindle.

[0028] The parts connected at the end faces can be connected by countersunk screws, and the countersunk holes provided on the corresponding parts are deep countersunk holes, that is, the axial depth of the countersunk holes is greater than the nut diameter of the connecting screws.

[0029] Preferably, the clamp is a 3R clamp.

[0030] The electric machining spindle based on the direct drive structure provided by the present invention has the following characteristics:

[0031] 1. The combination of torque motor and high-precision rotary encoder not only makes the rotational inertia of the driving component very small, but also makes the torque very large;

[0032] 2. Each shaft connection load-bearing part is rigidly connected through the end face, avoiding the reverse impact caused by the elastic coupling components, and ensuring the accuracy and stability of the electric spindle;

[0033] 3. Each of the aforementioned shaft-connected load-bearing components is subjected to weight reduction treatment by selecting materials, heat-treating them, and hollowing them out. This weight reduction treatment can be achieved by hollowing out the structure according to the finite element analysis commonly used in the prior art. The combination of these technologies can ensure the rigidity of the load-bearing components while taking into account their symmetry and moment of inertia.

[0034] 4. External seat parts are made of aluminum alloy, which can not only ensure the required rigidity requirements, but also greatly reduce the weight of non-core parts, ensuring the needs of air supply, liquid supply and power supply, making the structure optimized and the functions most complete;

[0035] 5. A rotary power supply method is adopted for power supply. On the structural shaft and structural seat, the air distribution structure and the oil distribution structure form a rotary air supply and rotary oil supply through annular grooves. This makes the power supply, air supply and oil supply structure simpler and more reliable, and also plays a role in reducing the weight of the components.

[0036] 6. The motor is built into the cavity formed by the outer adapter plate. The lower end face of the cavity is sealed by the inner adapter plate whose end face is fixed on the motor output shaft. As a result, the motor is set in the mounting base and becomes a built-in motor, which has good anti-collision and sealing properties and increases the life of the motor.

[0037] 7. The radial clearance between the motor and the external adapter plate is a small clearance fit, so that the motor and the motor mounting seat are concentric and the end faces are parallel;

[0038] Based on the above characteristics, the electric spindle provided by the present invention achieves the goals of high torque and high precision, with positioning accuracy and repeatability reaching 5" and 3". In contrast, the accuracy of most electric spindles with torque motor structures in the prior art is only 8-15 seconds. Therefore, the present invention fills the gap in high-precision C-axis for EDM machines.

[0039] The present invention is described in detail below with reference to the accompanying drawings and examples. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 A schematic structural diagram of an electric machining spindle based on a direct drive structure provided by the present invention;

[0041] Figure 2 for Figure 1 The figure shows a schematic diagram of the three-dimensional structure of an electric machining spindle based on a direct drive structure. DETAILED DESCRIPTION

[0042] like Figure 1 and Figure 2 As shown, the present invention provides an electric machining spindle based on a direct-drive structure, comprising a torque motor 1, an adapter mechanism consisting of inner and outer adapter plates 2 and 8, an insulation mechanism consisting of inner and outer marble insulating plates 3 and 9, a conductive mechanism of a rotating brush mechanism consisting of a conductive shaft 5 and a conductive seat 10, a centrally flushed and airtight flushing mechanism consisting of a structural shaft 22 and a structural seat 20, and a fixture 6. The inner adapter plate 2, inner insulating plate 3, conductive shaft 5, and structural shaft 22, which are fixedly connected to the output shaft of the torque motor 1, are rotating components, and the fixture is connected to the structural shaft 22, one of the rotating components. The outer adapter plate 8 is fixedly connected to the torque motor housing, and the outer insulating plate 9, conductive seat 10, and structural seat 20 are sequentially connected to the outer adapter plate, serving as a stationary component.

[0043] Specifically,

[0044] The connection structure of the rotating parts is as follows: the output shaft of the torque motor 1 is directly connected to the inner adapter plate 2, and the two are connected at their end faces. The inner adapter plate 2 is connected to the end face of the front end of the output shaft of the torque motor 1 by a bolt 11. The marble inner insulating plate 3 is connected to the upper end face of the inner adapter plate 2 by a screw 12. The end face of the conductive shaft 5 is connected to the inner adapter plate 2 by pressing the inner insulating plate 3 with a screw 13 with an insulating sleeve 4. The structural shaft 22 is connected to the end face of the conductive shaft 5 by a screw 18, and the 3R clamp 6 is connected to the end face of the structural shaft 22 by a screw 14.

[0045] The stationary components are connected as follows: the outer adapter plate 8 is connected to the Z-axis end face via screws 15; the outer insulating plate 9 is connected to the outer adapter plate 8 via screws 16; the conductive base 10 is connected to the outer adapter plate 8 via screws with insulating sleeves (not shown) passing through the outer insulating plate 9; and the structural base 20 is connected to the conductive base 10 via screws 18. A torque motor 1 and a built-in 24-bit rotary encoder provide the system with positioning and repeatability. The torque motor 1 is electrically non-conductive due to the isolation between the inner marble insulating plate 3 and the outer insulating plate 9. Carbon brushes 21a mounted on the conductive base 10 press against the conductive shaft 5 perpendicular to the axis of the electric spindle, thereby achieving electrical conductivity between the conductive shaft 5 and the 3R clamp 6 connected to its front end, enabling the electrode 21 clamped in the clamp 6 to perform electrical discharge machining.

[0046] In the flushing mechanism, the structural seat 20 is fixed on the end face of the conductive seat 10, which surrounds the outer circumference of the structural axis. A central flushing channel 22c and surrounding gas channels 22a and 22b are axially provided on the structural axis 22, and a liquid inlet and an air inlet are provided on the outer circumferential surface of the structural axis 22. The liquid inlet is connected to the flushing channel 22c, and the air inlet is connected to the gas channels 22a and 22b; a plurality of annular grooves are provided on the inner circumferential wall of the structural seat 20 corresponding to the liquid inlet and air inlet on the structural axis 22, and a perforation is provided at the bottom of each of the annular grooves on the structural seat 20. The annular grooves and the perforations constitute the structural seat flushing channel and the structural seat gas channel, so that the outer circumferential wall of the structural seat 20 is provided with air ports A, B and liquid port C corresponding to the liquid inlet and air inlet on the structural axis 22.

[0047] The sealing structure is a plurality of sealing rings 24, which are sleeved on the edges of the grooves on both sides of each of the annular grooves on the structural shaft 22, so that the grooves of the flushing channel on the structural seat 20 and the gas channel on the structural seat 20 are sealed at the connection between the liquid inlet and the gas inlet provided on the structural shaft 22;

[0048] The structural base 20, through six sealing structures, two air guide holes, and one liquid guide structure, aligns with the corresponding holes of the structural axis 22. This provides the 3R fixture 6 with pneumatic replacement of the electrode 21, end-face air blowing, and center-flushing. This allows for center flushing during auxiliary electrode 21 machining, loosening the clamp when replacing the electrode 21, and end-face air cleaning. The jaws on the fixture 6 clamp the electrode 21 when the gas channel is closed and release it when the gas channel is open, allowing for electrode replacement and air cleaning of the working end face.

[0049] When the torque motor 1 performs forward and reverse rotational motion under the control of the built-in rotary encoder, the components rigidly connected to the torque motor, such as the inner adapter plate 2, the marble inner insulating plate 3, the conductive shaft 5, the structural shaft 22, and the 3R clamp 6, synchronously perform corresponding rotational motion, and the electrode 21 performs corresponding motion under the clamping of the 3R clamp 6, thereby achieving high-precision positioning and repeatable positioning of the electrode 21.

[0050] The torque motor 1 is fixed to the bottom surface of the inner cavity of the outer adapter plate 8 through a tail end threaded connection. The end face of the outer adapter plate 8 is sequentially installed with a marble outer insulating plate 9, a conductive seat 10, and a structural seat 20. These four parts are concentric with the marble insulating plate 3, the conductive shaft 5, the structural shaft 22, the 3R clamp 6, etc. in the central motion component, and the carbon brush 21 installed in the conductive seat 10 provides a motion conductive path for the conductive shaft 5, the 3R clamp 6 and the electrode 21, thereby realizing the rotary discharge machining of the electrode 21; the structural seat 20 is aligned with the corresponding holes of the structural shaft 22 through six O-ring sealing structures and two air guide hole structure air ports A and B and one liquid guide structure oil port C, which can provide the 3R clamp 6 with pneumatic replacement of the electrode 21, end face blowing effect and center flushing effect, so that the center flushing can be performed during the auxiliary electrode 21 machining, the clamping can be loosened when the electrode 21 is replaced, and the end face blowing and cleaning can be performed.

[0051] The precision of the connection end faces of the rotating components connected to the shaft of the torque motor 1 is as follows: the form and position tolerance of each end face is: the total runout of the end face is 3-5 microns.

[0052] In the specific design, from the end face matching between the inner adapter plate 2 and the motor shaft to the end face matching between the structural shaft and the conductive shaft, the shape and position tolerance of the latter is greater than the shape and position tolerance of the former.

[0053] The conductive shaft 5 and the structural shaft 22 are made of 40cr steel and are subjected to surface tempering heat treatment, wherein the quenching is carried out by oil quenching at 830-860°C, so that the surface hardness reaches 45HRC.

[0054] The torque motor 1 and the outer adapter plate 8, i.e., the motor mounting seat, are matched with a small clearance, i.e., the clearance is 10 microns, so that the motor 1 and the motor seat, i.e., the outer adapter plate 8, are concentric and the end faces are parallel.

[0055] The inner insulating plate 3 and the outer insulating plate 9 of the fixing seat in the insulating mechanism are of equal height, thereby improving the rigidity of the structure and the insulation reliability.

[0056] The carbon brushes 21a are arranged symmetrically with respect to the axis of the electric spindle.

[0057] Several gas channels in the flushing mechanism are arranged symmetrically with respect to the axis of the electric spindle.

[0058] The outer adapter plate 8, the outer insulating plate 9, the conductive seat 10 and the structural seat 20 are made of aluminum alloy structural parts.

[0059] A symmetrical hollow structure is provided inside at least one of the inner adapter plate 2, the inner insulating plate 3, the conductive shaft 5 and the structural shaft 22, so as to reduce the overall rotational inertia of the entire electric spindle.

[0060] The center of the torque motor 1 is also a hollow structure.

[0061] The parts fixedly connected at the end faces are connected by countersunk screws, and the countersunk holes provided on the corresponding parts are deep countersunk holes, that is, the axial depth of the countersunk holes is greater than the nut diameter of the connecting screws.

[0062] The present invention utilizes the aforementioned design of a torque motor with a rotating conductive stage and marble inner and outer ring insulation to achieve an electrical machining insulation effect and mechanism to control the spindle's weight and moment of inertia. The operating principle of a torque motor with a rotating electrode conductive structure is generally similar to that of a conventional motor transmission system. The main difference is that the torque motor replaces the conventional motor as the operating power source. This not only addresses the problems of conventional motors, such as large moment of inertia, low motion control accuracy, and backlash during forward and reverse switching, but also reduces the impact and oscillation of the coupling in the circuit, thereby improving the spindle's positioning accuracy and response rate.

[0063] The present invention uses a direct-drive motor, a marble inner and outer ring insulation mechanism, a rotating brush mechanism, a center flush, an air seal and a fixture blowing structure. The rotating axes are all arranged symmetrically to avoid the influence of eccentric loads, have a fast dynamic response, and improve the motion accuracy of the machine tool spindle, thereby improving the processing efficiency and processing accuracy.

[0064] The positioning accuracy and repeatability of existing electric spindles are generally 15 seconds and 8 seconds respectively. However, the positioning accuracy of the electric spindle designed above can reach 5 seconds and the repeatability can reach 3 seconds.

Claims

1. An electric machining spindle based on a direct drive structure, characterized by: Including motor, switching mechanism, insulation mechanism, conductive mechanism, flushing mechanism, sealing structure and fixture, The adapter mechanism includes an inner adapter plate and an outer adapter plate, wherein the inner adapter plate is fixed to the end face of the output shaft of the motor, and the outer adapter plate is connected to the motor housing, and the motor is built into a chamber formed by the inner and outer adapter plates; The insulating mechanism includes a rigid inner insulating plate and an outer insulating plate, wherein the inner insulating plate is fixed to the end surface of the inner adapter plate, and the outer insulating plate is fixed to the outer adapter plate and surrounds the outer periphery of the inner insulating plate; The conductive mechanism includes a conductive shaft and a conductive seat. The conductive shaft is fixed to the end surface of the inner insulating plate, and the conductive seat is fixed to the end surface of the outer insulating plate. The conductive seat surrounds the outer circumference of the conductive shaft. A plurality of carbon brush mounting holes are circumferentially provided on the conductive seat. Carbon brushes are elastically arranged radially in the holes so that the carbon brushes are pressed against the conductive shaft and conduct electricity to the conductive shaft. The flushing mechanism includes a structural shaft and a structural seat, the structural shaft is fixed on the end surface of the conductive shaft, the structural seat is fixed on the end surface of the conductive seat, and surrounds the outer circumference of the structural shaft, and a central flushing channel and a surrounding gas channel are axially provided on the structural shaft, and a liquid inlet and an air inlet are provided on the outer circumferential surface of the structural shaft, the liquid inlet is connected to the flushing channel, and the air inlet is connected to the gas channel; a plurality of annular grooves are provided on the inner circumferential wall of the structural seat, corresponding to the liquid inlet and the air inlet on the structural shaft, and a through-hole is provided at the bottom of each of the annular grooves on the structural seat, and the annular grooves and the through-holes constitute the structural seat flushing channel and the structural seat gas channel, so that an inlet corresponding to the liquid inlet and the air inlet on the structural shaft is opened on the outer circumferential wall of the structural seat; The sealing structure is a plurality of sealing rings, which are sleeved on the edges of the grooves on both sides of each of the annular grooves on the structural shaft, so as to seal the connection between the grooves of the structural seat flushing channel and the structural seat gas channel and the liquid inlet and the gas inlet provided on the structural shaft; The clamp includes a clamp seat and a clamping jaw. The clamp seat is fixed on the end face of the structural shaft. The clamping jaw can be elastically reset and fixed on the clamp seat. A central flushing channel is provided on the clamp seat and is connected to the flushing channel on the structural shaft. A clamping jaw gas channel is provided on the spring structure of each clamping jaw and is connected to the gas channel on the structural shaft.

2. The electric machining spindle according to claim 1, characterized in that: The output shaft of the motor and the inner adapter plate in the adapter mechanism, the inner insulating plate in the insulating mechanism, the conductive shaft in the conductive mechanism, the structural shaft in the flushing mechanism and the fixture are arranged coaxially; and / or, The motor is a torque motor; and / or, The end face accuracy of each rotating component connected to the motor shaft and fixed at the end face is: the form and position tolerance of each end face is: the end face total runout is 3-5 microns; and / or, The hardness of the connecting end surfaces of the conductive shaft, the structural shaft and the fixture seat in the fixture is 40HRC-50HRC; and / or, The inner insulating plate is made of marble.

3. The electric machining spindle according to claim 2, characterized in that: The torque motor is provided with a 24-bit rotary encoder to complete the positioning and repositioning of the electric spindle; and / or, From the point where the inner adapter plate fits in with the end face of the motor shaft to the point where the fixture seat fits in with the end face of the structural shaft, the shape and position tolerances of the latter are greater than the shape and position tolerances of the former; and / or, The conductive shaft and the structural shaft are made of 40cr steel and are subjected to surface tempering heat treatment, wherein the quenching is performed by oil quenching at 830-860°C.

4. The electric machining spindle according to claim 1, 2 or 3, characterized in that: The motor and the outer adapter plate, i.e., the motor mounting seat, are matched with a small gap, i.e., the gap is 8-12 microns; and / or, the inner insulating plate of the rotating part and the outer insulating plate of the fixed seat in the insulating mechanism are structures of equal height; and / or, The plurality of carbon brushes in the conductive mechanism are symmetrically arranged on the circumference of the conductive shaft relative to the axis of the electric spindle; and / or, The carbon brushes are arranged symmetrically with respect to the axis of the electric spindle; and / or, The plurality of gas channels in the flushing mechanism are arranged symmetrically relative to the axis of the electric spindle.

5. The electric machining spindle according to claim 1, 2 or 3, characterized in that: At least one of the outer adapter plate, outer insulating plate, conductive base and structural base is made of aluminum alloy; and / or A symmetrical hollow structure is provided inside at least one of the inner adapter plate, the inner insulating plate, the conductive shaft and the structural shaft, so as to reduce the overall rotational inertia of the entire electric spindle; and / or, The parts fixedly connected at the end faces are connected by countersunk screws, and the countersunk holes provided on the corresponding parts are deep countersunk holes, that is, the axial depth of the countersunk holes is greater than the nut diameter of the connecting screws.

6. The electric machining spindle according to claim 4, characterized in that: At least one of the outer adapter plate, outer insulating plate, conductive base and structural base is made of aluminum alloy; and / or A symmetrical hollow structure is provided inside at least one of the inner adapter plate, the inner insulating plate, the conductive shaft and the structural shaft, so as to reduce the overall rotational inertia of the entire electric spindle; and / or, The parts fixedly connected at the end faces are connected by countersunk screws, and the countersunk holes provided on the corresponding parts are deep countersunk holes, that is, the axial depth of the countersunk holes is greater than the nut diameter of the connecting screws.

7. The electric machining spindle according to claim 1, characterized in that: The clamp is a 3R clamp.

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