WO2022178980A1

WO2022178980A1 - Motor spindle and drilling machine

Info

Publication number: WO2022178980A1
Application number: PCT/CN2021/092492
Authority: WO
Inventors: 张翰乾; 黄敏强; 程振涛; 汤丽君; 汤秀清
Original assignee: 广州市昊志机电股份有限公司
Priority date: 2021-02-25
Filing date: 2021-05-08
Publication date: 2022-09-01
Also published as: CN112893891A

Abstract

A motor spindle and a drilling machine, comprising: a body assembly (1), comprising an aluminum alloy body (11) and a steel sleeve (12), the steel sleeve (12) being sleeved outside the aluminum alloy body (11) and forming a whole piece with the aluminum alloy body (11), and the aluminum alloy body (11) being provided with an axial hole; a shaft core assembly (2), provided in the axial hole and supported on the aluminum alloy body (11) by means of an upper bearing assembly (4) and a lower bearing assembly (5); and a motor assembly (3), configured to drive the shaft core assembly (2) to rotate. The upper bearing assembly (4) comprises an upper bearing seat (41) and an upper bearing (42); the lower bearing assembly (5) comprises a lower bearing seat (51) and a lower bearing (52); the upper bearing seat (41) and/or the lower bearing seat (51) are integrally manufactured together with the aluminum alloy body (11).

Description

An electric spindle and drilling rig

technical field

The invention is used in the field of working spindles, and particularly relates to an electric spindle and a drilling rig.

Background technique

With economic development and technological advancement, PCB drilling machines with higher processing efficiency have been developed. The Z-axis system movement acceleration of PCB drilling machines on the market exceeds 3G, and the Z-axis system structure of the drilling machine itself is theoretically drilled after extreme optimization. The number of holes reaches 800 holes/min, but it faces the problem that the weight of the spindle cannot be reduced (the greater the weight of the spindle, the greater the inertia, and the lower the limit processing efficiency of the PCB drilling machine), which seriously reduces the processing efficiency of the PCB drilling machine.

With the miniaturization of electronic components and the increasingly complex functions of various electrical appliances, the integration of PCB boards is also getting higher and higher, and the micro holes (Φ0.05-Φ0.2mm) on the PCB are becoming more and more dense. The PCB board is made of a variety of materials with different thermal expansion coefficients (such as epoxy resin, copper foil, etc.), which greatly increases the difficulty of drilling. The quality of hole processing, especially the roughness of the hole wall, is directly related to the quality of subsequent copper deposition and electroplating, as well as the reliability and life of electronic products. Especially in the case of continuous drilling, the high-speed friction between the drill bit and the hole wall increases the cutting temperature, and the resin of the circuit board is melted, stains and other serious phenomena. In order to improve the drilling efficiency of dense holes and improve the drilling quality of tiny holes, ultra-high-speed drilling must be used to solve the problem.

In addition, in the process of ultra-high-speed drilling of small holes, the phenomenon of broken needles often occurs. One of the reasons is that the verticality of the electric spindle is not good, and it is impossible to ensure that the drilling needles are perpendicular to the PCB board during the high-speed drilling process.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve at least one of the technical problems existing in the prior art, and to provide an electric spindle and a drilling rig, which can reduce the weight of the spindle itself, improve the drilling efficiency, enhance the overall rigidity of the spindle, and eliminate assembly errors. , to ensure the verticality of the main axis.

The technical scheme adopted by the present invention to solve its technical problems is:

In a first aspect, an electric spindle includes:

a body assembly, including an aluminum alloy body and a steel sleeve, the steel sleeve is sleeved outside the aluminum alloy body, and forms a whole with the aluminum alloy body, and the aluminum alloy body is provided with an axial hole;

The shaft core assembly is arranged in the axial hole, and is supported on the aluminum alloy body through the upper bearing assembly and the lower bearing assembly;

a motor assembly for driving the shaft core assembly to rotate;

Wherein, the upper bearing assembly includes an upper bearing seat and an upper bearing, the lower bearing assembly includes a lower bearing seat and a lower bearing, and the upper bearing seat and/or the lower bearing seat are integrally fabricated with the aluminum alloy body.

With reference to the first aspect, in some implementations of the first aspect, the aluminum alloy body is provided with an annular boss inside the axial hole, and the annular boss forms the upper bearing seat and the lower bearing The seat is detachably arranged on the body assembly, the lower bearing seat is located below the upper bearing seat, a space is left between the upper bearing seat and the lower bearing seat, and the motor assembly is arranged in the space , the motor assembly includes a stator and a rotor, the stator is fixedly connected to the aluminum alloy body, and the rotor is fixedly connected to the shaft core assembly.

In combination with the first aspect and the above implementations, in some implementations of the first aspect, the upper bearing adopts an upper air bearing, the lower bearing adopts a lower air bearing, and the shaft core assembly is provided with a flying disc, so The body assembly is provided with a thrust air bearing assembly matched with the flying disc, and the body assembly is provided with an air passage communicating with the upper air bearing, the lower air bearing and the thrust air bearing assembly.

In combination with the first aspect and the above implementations, in some implementations of the first aspect, the annular boss is provided with a bearing installation cavity, the upper air bearing is installed in the bearing installation cavity, and locked by the bearing pressure plate tight.

In combination with the first aspect and the above implementations, in some implementations of the first aspect, the flying disc is disposed at the lower end of the shaft core assembly, the lower end of the steel sleeve protrudes from the aluminum alloy body, and the steel An installation groove is formed inside the sleeve under the aluminum alloy body, and the thrust air bearing assembly is installed in the installation groove and abuts with the aluminum alloy body above and the outer steel sleeve respectively.

In combination with the first aspect and the foregoing implementations, in some implementations of the first aspect, further includes:

A cooling medium flow channel for cooling the upper bearing assembly and/or the lower bearing assembly and/or the thrust air bearing assembly and/or the motor assembly.

In combination with the first aspect and the above-mentioned implementations, in some implementations of the first aspect, the shaft core assembly includes a shaft core and a broach assembly disposed at the lower end of the shaft core, and the upper end of the body assembly is provided with a knife cylinder.

In combination with the first aspect and the above implementations, in some implementations of the first aspect, the stator has a first winding and a second winding, and further includes a first contactor, a second contactor, and a frequency converter, the first A winding is connected to the inverter, the second winding is connected to a first circuit and a second circuit, the first circuit short-circuits the power line of the second winding, and the second circuit connects the second The winding is connected to the frequency converter, the first contactor is arranged on the first circuit, and the second contactor is arranged on the second circuit.

machine control terminal;

a first output circuit for transmitting the output signal of the machine tool control end to the first contactor;

a first feedback circuit for feeding back the state signal of the second contactor to the control end of the machine tool;

a second output circuit for transmitting the output signal of the machine tool control end to the second contactor;

a second feedback circuit for feeding back the state signal of the first contactor to the control end of the machine tool;

a control circuit for outputting a control signal to the frequency converter after the machine tool control terminal receives the state signal of the first feedback circuit or the second feedback circuit;

an auxiliary circuit for interlocking the first contactor and the second contactor.

In a second aspect, a drilling rig includes the electric spindle according to any one of the implementations of the first aspect.

One of the technical solutions in the above-mentioned technical solutions has at least one of the following advantages or beneficial effects:

The invention adopts the aluminum alloy body of low-density material and the high-rigidity steel sleeve to form the body assembly, which not only reduces the weight of the main shaft, but also ensures the overall rigidity of the main shaft and improves the drilling efficiency.

At the same time, the upper bearing seat and/or the lower bearing seat are made integrally with the aluminum alloy body, and the structure is integrated with the body, which eliminates the assembly error of the previous bearing seat as a separate part, ensures the verticality of the main shaft, and effectively ensures the high-speed drilling process. The verticality of the drill pin prevents the drill pin from breaking.

Additional aspects and advantages of the present invention will be set forth, in part, from the following description, and in part will be apparent from the following description, or may be learned by practice of the invention.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of embodiments taken in conjunction with the accompanying drawings, wherein:

1 is a schematic structural diagram of an embodiment of an electric spindle of the present invention;

FIG. 2 is a schematic structural diagram of the body assembly of an embodiment shown in FIG. 1;

FIG. 3 is a schematic structural diagram of the upper bearing assembly of the embodiment shown in FIG. 1;

FIG. 4 is a schematic structural diagram of the stator of an embodiment shown in FIG. 1;

FIG. 5 is a schematic cross-sectional view of the upper bearing seat of the embodiment shown in FIG. 1;

Fig. 6 is a schematic cross-sectional view of an embodiment of the aluminum water jacket shown in Fig. 1;

FIG. 7 is a schematic diagram of the embodiment shown in FIG. 1 when the second winding is short-circuited;

Fig. 8 is a schematic diagram when the second winding of the embodiment shown in Fig. 1 is connected to the frequency converter;

FIG. 9 is a schematic diagram of the circuit principle of an embodiment shown in FIG. 1 .

Detailed ways

This part will describe the specific embodiments of the present invention in detail, and the preferred embodiments of the present invention are shown in the accompanying drawings. Each technical feature and overall technical solution of the invention should not be construed as limiting the protection scope of the invention.

In the present invention, if there is a description of a direction (up, down, left, right, front and rear), it is only for the convenience of describing the technical solution of the present invention, rather than indicating or implying that the technical features referred to must have specific characteristics Orientation, construction and operation in a particular orientation, and therefore should not be construed as limiting the invention.

In the present invention, "several" means one or more, "multiple" means two or more, "greater than", "less than", "exceeding", etc. are understood as not including this number; "above", "below" and "within" " etc. are understood to include the original number. In the description of the present invention, if it is described that "first" and "second" are only used for the purpose of distinguishing technical features, it should not be understood as indicating or implying relative importance or implying the number of indicated technical features or Implicitly indicates the order of the indicated technical features.

In the present invention, unless otherwise clearly defined, words such as "set", "install" and "connect" should be understood in a broad sense, for example, it may be directly connected or indirectly connected through an intermediate medium; it may be a fixed connection or a The detachable connection can also be integrally formed; it can be a mechanical connection or an electrical connection or can communicate with each other; it can be the internal communication between the two elements or the interaction relationship between the two elements. Those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solutions.

1 shows the reference direction coordinate system of the embodiment of the present invention, and the following describes the embodiment of the present invention with reference to the directions shown in FIG. 1 .

Referring to FIG. 1 , an embodiment of the present invention provides an electric spindle, which includes a body assembly 1 , a shaft core assembly 2 and a motor assembly 3 .

Due to the same volume, the lower the material density is, the smaller the mass is. Most of the electric spindles in the prior art are made of steel, resulting in too much weight of the spindle itself. 1 and 2, the body assembly 1 of the embodiment of the present invention includes an aluminum alloy body 11 and a steel sleeve 12. The outer circumference of the aluminum alloy body 11 forms a cylindrical surface, the steel sleeve 12 is cylindrical, and the steel sleeve 12 is sleeved on the aluminum alloy. The outside of the body 11 is integral with the aluminum alloy body 11 , and the aluminum alloy body 11 is provided with an axial hole for installing the shaft core assembly 2 . The embodiment of the present invention adopts the aluminum alloy body 11 of low density material and the steel sleeve 12 of high rigidity to form the body assembly 1, which not only reduces the weight of the main shaft, but also ensures the overall rigidity of the main shaft and improves the drilling efficiency.

Among them, the aluminum alloy body 11 and the steel sleeve 12 can be connected as a whole by means of interference fit, screw connection, etc., so as to achieve relative fixation. For example, in the embodiment shown in FIG. 2 , the exterior of the aluminum alloy body 11 is protected by a steel sleeve 12 , and the outer steel sleeve 12 is fixed to the aluminum alloy body 11 by two upper and lower positioning pins 13 to form the body assembly 1 . This structural design achieves lightening The purpose of the spindle's own weight and the enhancement of the overall stiffness of the spindle. At the same time, the aluminum alloy body 11 and the steel sleeve 12 are fixed by pins 13, which further ensures the relative positional accuracy of the aluminum alloy body 11 and the steel sleeve 12, and makes the assembly of the aluminum alloy body 11 and the steel sleeve 12 more convenient.

Referring to FIG. 1 , the shaft core assembly 2 is disposed in the axial hole, and is supported on the aluminum alloy body 11 through the upper bearing assembly 4 and the lower bearing assembly 5 . The motor assembly 3 is located in the middle or the tail of the body assembly 1 , and the motor assembly 3 is used to drive the shaft core assembly 2 to rotate. Driven by the motor assembly 3, the shaft core assembly 2 further drives the drill and other tools to rotate to realize processing.

In actual processing, the Z-axis system of the drilling machine clamps the main shaft to drill down vertically. If the verticality of the main shaft itself is not good, the drill needle is easily inclined and broken. 1 , in the embodiment of the present invention, the upper bearing assembly 4 includes an upper bearing seat 41 and an upper bearing 42 , the lower bearing assembly 5 includes a lower bearing seat 51 and a lower bearing 52 , and the upper bearing seat 41 and/or the lower bearing seat 51 It is integrated with the aluminum alloy body 11. By integrating the upper bearing seat 41 and/or the lower bearing seat 51 with the aluminum alloy body 11 and integrating the body, the assembly error of the previous bearing seat as a separate part is eliminated, the verticality of the main shaft is ensured, and the high-speed drilling is effectively guaranteed. The verticality of the drill needle during the hole process can avoid the phenomenon of the drill needle breaking.

In some embodiments, referring to FIGS. 1 and 2 , the aluminum alloy body 11 is provided with an annular boss inside the axial hole, the diameter of the axial hole is reduced at the annular boss, and the annular boss forms the upper bearing seat 41 . The lower bearing seat 51 is detachably disposed on the body assembly 1 , and the lower bearing seat 51 is located below the upper bearing seat 41 . That is, in this embodiment, the upper bearing seat 41 and the aluminum alloy body 11 are integrally fabricated, the lower bearing seat 51 and the body assembly 1 adopt a split structure, and the lower bearing seat 51 is detachably disposed on the body assembly 1 . In this embodiment, the upper bearing seat 41 and the aluminum alloy body 11 are integrally fabricated, and the structure is integrated with the body, which eliminates the assembly error of the previous bearing seat as a separate part, and ensures the verticality of the main shaft.

Further, referring to FIG. 1, a space is left between the upper bearing seat 41 and the lower bearing seat 51, the upper bearing seat 41 and the lower bearing seat 51 are separated by a certain distance in the axial direction, the motor assembly 3 is arranged in the space, and the motor The assembly 3 includes a stator 31 and a rotor 32 . The stator 31 is fixedly connected to the aluminum alloy body 11 , and the rotor 32 is fixedly connected to the shaft core assembly 2 . The detachable lower bearing seat 51 facilitates the installation and adjustment of the shaft core assembly 2 and the motor assembly 3 . At the same time, the motor assembly 3 adopts a central structure, which can better meet the processing needs of high-speed drilling.

The upper bearing 42 and the lower bearing 52 may adopt rolling bearings or air bearing. For example, in the embodiment shown in FIG. 1 , the upper bearing 42 adopts an upper air bearing, and the lower bearing 52 adopts a lower air bearing. In order to bear the axial force of the shaft assembly, the shaft assembly 2 is provided with a flying disc 21, the body assembly 1 is provided with a thrust air bearing assembly 6 that cooperates with the flying disc 21, and the body assembly 1 is provided with an upper air bearing and a lower air bearing. The air passage 14 communicating between the bearing and the thrust air bearing assembly 6 . Through external air supply, a pressure air film is formed between the shaft assembly 2 and the upper air bearing, the lower air bearing and the thrust air bearing assembly 6, the supporting shaft assembly 2 is in a suspended state, and the stator 31 drives the shaft assembly 2 at high speed rotate.

Further, referring to Figures 2 and 3, the annular boss is provided with a bearing installation cavity 43, the upper air bearing is installed in the bearing installation cavity 43, the air path 14 of the body assembly 1 is directly connected to the bearing installation cavity 43, and the upper air bearing is installed in the bearing installation cavity 43. The upper end of the bearing is in contact with the top edge of the bearing installation cavity 43 , and the lower end is locked by the bearing pressing plate 44 . The upper bearing seat 41 is made in one piece with the body assembly 1, which eliminates the assembly error of the previous air-floating spindle bearing seat as a separate part, and ensures the verticality of the spindle.

The flying disc 21 can be arranged at the middle, upper end or lower end of the shaft core assembly 2, for example, in the embodiment shown in FIG. The lower end, such a position setting, can make the thrust air bearing assembly 6 and the flying disc 21 closer to the output end of the shaft core assembly 2, and reduce the influence of the axial floating of the thrust air bearing assembly 6 on the rotation accuracy of the shaft core assembly 2.

Further, referring to FIG. 1 , the lower end of the steel sleeve 12 protrudes from the aluminum alloy body 11 , the axial dimension of the steel sleeve 12 is longer than that of the aluminum alloy body 11 , the steel sleeve 12 and the aluminum alloy body 11 form a stepped structure, and the steel sleeve 12 forms a stepped structure. 12. A mounting groove 15 is formed inside the aluminum alloy body 11, and the thrust air bearing assembly 6 is installed in the mounting groove 15, and is respectively abutted with the aluminum alloy body 11 above and the steel sleeve 12 on the outside, that is, through the steel sleeve 12 and the outer steel sleeve 12. The stepped structure formed by the aluminum alloy body 11 realizes the installation and positioning of the thrust air bearing assembly 6 on the body assembly 1 , and closes the lower port of the body assembly 1 .

Referring to FIG. 1 , the electric spindle also includes a cooling medium flow channel and an aluminum water jacket 7 . The aluminum water jacket 7 is arranged on the upper end of the body assembly 1 , and the aluminum water jacket 7 is provided with a gas interface and a cooling liquid interface. The cooling medium flow channel is used for cooling the upper bearing assembly 4 and/or the lower bearing assembly 5 and/or the thrust air bearing assembly 6 and/or the motor assembly 3 . During operation, the coolant is cooled by the aluminum water jacket 7 , the body assembly 1 , and the thrust bearing assembly to cool the lower bearing assembly 5 , the thrust bearing assembly, the upper bearing assembly 4 and the motor assembly 3 .

In some embodiments, the shaft core assembly 2 includes a shaft core 22 and a broach assembly 23 disposed at the lower end of the shaft core 22 , and the upper end of the body assembly 1 is provided with a cutting cylinder 8 . The gas punches the shaft core assembly 2 through the punching cylinder 8, so that the spindle can automatically change the tool.

It can be understood that, the shaft core assembly 2 can also realize the connection between the tool and the shaft core 22 by means of clamping or the like, and ensure the tool changing function.

In the prior art, the commonly used air-floating high-speed PCB drilling electromechanical spindles cannot take into account both large holes and small holes at the same time. The spindle that can drill large holes cannot process small holes (the speed cannot increase), and the spindle that can drill small holes cannot drill large holes. (Low power at low speed) In addition to the fact that it is difficult to meet high standards due to the performance of air-floating shaft cores and bearings, it is also faced with major challenges such as selection of motors and external wiring methods of motors. In some embodiments, referring to FIGS. 4-8 , the stator 31 has a first winding 33 and a second winding 34 , that is, the electrospindle adopts a double-winding motor. The first winding 33 has a set of power lines U, V, W, the second winding 34 has another set of power lines X, Y, Z, the power lines pass through the body stator wire hole 45 (see FIG. 5), molten aluminum Set the power cable through the wire hole 71 (see Figure 6), and finally lead it out through the power connector. See Figure 7, the spindle low-speed winding connection method: X, Y, Z lines are short-circuited, U, V, W form three-phase (the spindle torque is large, suitable for drilling large holes at low speed). Referring to Figure 8, the high-speed winding connection method of the spindle: U, V, and W lines are connected to Z, X, and Y respectively to form a three-phase line (the spindle has a high speed and is suitable for drilling micro-holes).

In practical applications, the winding can be switched by changing the wiring method, but switching the winding by manually switching the wiring method is extremely wasteful of man-hours, and due to the large current output by the inverter to the spindle (the instantaneous current can exceed 10A), the incorrect switching of the winding is very easy to cause. Safety accident, so the embodiment of the present invention designs a set of wiring scheme of the double-winding spindle: realizes the automatic switching of high and low-speed windings of the high-speed and low-speed air-floating spindle. Referring to FIG. 9, the electric spindle also includes a first contactor 81, a second contactor The contactor 82 and the inverter 83, the first winding 33 is connected to the inverter 83, the second winding 34 is connected to the first circuit 84 and the second circuit 85, the first circuit 84 short-circuits the power line of the second winding 34, the second The circuit 85 connects the second winding 34 to the frequency converter 83 , the first contactor 81 is arranged on the first circuit 84 , and the second contactor 82 is arranged on the second circuit 85 , which are used to control the first circuit 84 and the second circuit 85 respectively. disconnection or connection.

Further, referring to FIG. 9 , the electric spindle further includes a machine tool control terminal 86 , a first output circuit 87 , a first feedback circuit 88 , a second output circuit 89 , a second feedback circuit 810 , a control circuit 811 and an auxiliary circuit 812 . The first output circuit 87 is used to transmit the output signal of the machine tool control end 86 to the first contactor 81, and the first feedback circuit 88 is used to feed back the state signal of the second contactor 82 to the machine tool control end 86; the second output circuit 89 is used to transmit the output signal of the machine tool control end 86 to the second contactor 82; the second feedback circuit 810 is used to feed back the state signal of the first contactor 81 to the machine tool control end 86; the control circuit 811 is used to control the machine tool The terminal 86 outputs a control signal to the frequency converter 83 after receiving the state signal of the first feedback circuit 88 or the second feedback circuit 810 . The output signal of the machine tool control terminal 86 controls the action of the first contactor 81 and the second contactor 82 to realize the switching of the high-speed and low-speed high-low-speed windings of the air-floating spindle (when the first contactor 81 is closed and the second contactor 82 is not closed, then It is the spindle low-speed winding connection method; when the second contactor 82 is closed and the first contactor 81 is not closed, it is the spindle high-speed winding connection method), after the winding is switched, the feedback signal is sent to the machine tool control terminal 86 (receive the feedback signal, judge the winding Switching situation) and then control the inverter 83 to drive the spindle to run, if the winding switching (high and low-speed windings switch each other) is realized, the machine tool control terminal 86 needs to control the inverter 83 to stop the spindle in advance, and the first contactor 81, the second contact After the correct switching of the contactor 82, the inverter 83 is controlled to drive the main shaft to run, so as to avoid arcing caused by the switching of the contactor when the power is turned on, and realize the safe, fast and accurate switching of the motor windings. Drilling of very large and small holes through an air-floating electric spindle is achieved through the appeal scheme.

Wherein, the auxiliary circuit 812 is used for the first contactor 81 and the second contactor 82 to form an interlock. That is, after power-on, the first contactor 81 and the second contactor 82 cannot be closed at the same time, so as to avoid a short circuit of the line.

An embodiment of the present invention also provides a drilling rig including the electric spindle in any of the above embodiments.

In the description of this specification, a description with reference to the terms "example", "embodiment" or "some embodiments" etc. means that a particular feature, structure, material or characteristic described in connection with the embodiment or example is included in at least one aspect of the present invention in one embodiment or example. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Of course, the present invention is not limited to the above-mentioned embodiments, and those skilled in the art can also make equivalent modifications or replacements without departing from the spirit of the present invention, and these equivalent modifications or replacements are included in the claims of the present application. within a limited range.

Claims

An electric spindle, characterized in that, comprising:

a body assembly, including an aluminum alloy body and a steel sleeve, the steel sleeve is sleeved outside the aluminum alloy body, and forms a whole with the aluminum alloy body, and the aluminum alloy body is provided with an axial hole;

The shaft core assembly is arranged in the axial hole, and is supported on the aluminum alloy body through the upper bearing assembly and the lower bearing assembly;

a motor assembly for driving the shaft core assembly to rotate;

Wherein, the upper bearing assembly includes an upper bearing seat and an upper bearing, the lower bearing assembly includes a lower bearing seat and a lower bearing, and the upper bearing seat and/or the lower bearing seat are integrally fabricated with the aluminum alloy body.
The electric spindle according to claim 1, wherein the aluminum alloy body is provided with an annular boss inside the axial hole, the annular boss forms the upper bearing seat, and the lower bearing seat can be The disassembled is arranged on the body assembly, the lower bearing seat is located below the upper bearing seat, a space is left between the upper bearing seat and the lower bearing seat, and the motor assembly is arranged in the space, so The motor assembly includes a stator and a rotor, the stator is fixedly connected to the aluminum alloy body, and the rotor is fixedly connected to the shaft core assembly.
The electric spindle according to claim 2, wherein the upper bearing adopts an upper air bearing, the lower bearing adopts a lower air bearing, the shaft core assembly is provided with a flying disc, and the body assembly is provided with a In the thrust air bearing assembly matched with the flying disc, the body assembly is provided with an air passage communicating with the upper air bearing, the lower air bearing and the thrust air bearing assembly.
The electric spindle according to claim 3, wherein the annular boss is provided with a bearing installation cavity, and the upper air bearing is installed in the bearing installation cavity and locked by a bearing pressure plate.
The electric spindle according to claim 3, wherein the flying disc is arranged at the lower end of the shaft core assembly, the lower end of the steel sleeve protrudes from the aluminum alloy body, and the steel sleeve is inside the aluminum alloy body. An installation groove is formed under the alloy body, and the thrust air bearing assembly is installed in the installation groove and abuts with the aluminum alloy body above and the outer steel sleeve respectively.
The electric spindle according to claim 3, characterized in that, further comprising:

A cooling medium flow channel for cooling the upper bearing assembly and/or the lower bearing assembly and/or the thrust air bearing assembly and/or the motor assembly.
The electric spindle according to claim 1, wherein the shaft core assembly comprises a shaft core and a broach assembly disposed at the lower end of the shaft core, and the upper end of the body assembly is provided with a cutter cylinder.
The electric spindle according to claim 2, wherein the stator has a first winding and a second winding, and further comprises a first contactor, a second contactor and a frequency converter, the first winding and the frequency converter The second winding is connected to a first circuit and a second circuit, the first circuit short-circuits the power line of the second winding, and the second circuit connects the second winding to the inverter connection, the first contactor is arranged on the first circuit, and the second contactor is arranged on the second circuit.
The electric spindle according to claim 8, characterized in that, further comprising:

Machine tool control terminal;

a first output circuit for transmitting the output signal of the machine tool control end to the first contactor;

a first feedback circuit for feeding back the state signal of the second contactor to the control end of the machine tool;

a second output circuit for transmitting the output signal of the machine tool control end to the second contactor;

a second feedback circuit for feeding back the state signal of the first contactor to the machine tool control end;

a control circuit for outputting a control signal to the frequency converter after the machine tool control terminal receives the state signal of the first feedback circuit or the second feedback circuit;

an auxiliary circuit for interlocking the first contactor and the second contactor.
A drilling rig is characterized by comprising the electric spindle according to any one of claims 1 to 9.