阅读说明：本技术 一种基于液态金属冷却的电主轴及高速异步电机 (Electric spindle and high-speed asynchronous motor based on liquid metal cooling ) 是由 李法敬 黄彦博 李子豪 柴牧 王道勇 王志锋 于 2021-09-02 设计创作，主要内容包括：本发明公开了一种基于液态金属冷却的电主轴及高速异步电机,所述电主轴包括壳体、定子、转子、转轴和冷却模块；转轴内的冷却循环通道内装有液态金属；所述冷却模块包括导体和永磁铁组；所述导体对称设置在所述转轴的径向方向的两侧,该导体两端分别伸入到冷却循环通道的两侧；两组永磁铁组分别位于导体的轴线方向的两侧；每组永磁铁组中的N极和S极设在转轴径向方向的两侧；且两组永磁铁组中的N极和S极的设置位置相反；所述转轴的端部位于冷却室中,所述壳体上设置有与冷却室连通的冷却液进口和冷却液出口。本发明的电主轴可以实现电主轴轴心热量的快速导出,有效地控制电主轴轴心处的温升,减小热变形,提高加工精度。(The invention discloses an electric spindle and a high-speed asynchronous motor based on liquid metal cooling, wherein the electric spindle comprises a shell, a stator, a rotor, a rotating shaft and a cooling module; liquid metal is filled in a cooling circulation channel in the rotating shaft; the cooling module comprises a conductor and a permanent magnet group; the conductors are symmetrically arranged on two sides of the rotating shaft in the radial direction, and two ends of each conductor extend into two sides of the cooling circulation channel respectively; the two groups of permanent magnet groups are respectively positioned at two sides of the axial direction of the conductor; the N pole and the S pole in each group of permanent magnet groups are arranged on two sides of the rotating shaft in the radial direction; the arrangement positions of the N pole and the S pole in the two groups of permanent magnet groups are opposite; the end part of the rotating shaft is positioned in the cooling chamber, and the shell is provided with a cooling liquid inlet and a cooling liquid outlet which are communicated with the cooling chamber. The electric spindle can realize quick conduction of heat of the axis of the electric spindle, effectively control temperature rise at the axis of the electric spindle, reduce thermal deformation and improve processing precision.)

1. An electric spindle based on liquid metal cooling comprises a shell, a stator, a rotor, a rotating shaft and a cooling module, wherein the stator, the rotor and the rotating shaft are arranged in the shell, the cooling module is used for cooling the rotating shaft,

the rotating shaft is positioned in the rotor, a cooling circulation channel is arranged in the rotating shaft, the cooling circulation channel extends along the axis direction of the rotating shaft, and liquid metal is filled in the cooling circulation channel;

the cooling module comprises conductors and permanent magnet groups, wherein the conductors are arranged on the rotating shaft in at least two groups and are symmetrically arranged on two sides of the rotating shaft in the radial direction, each group of conductors extends along the axial direction of the rotating shaft, and two ends of each conductor respectively extend into two sides of the cooling circulation channel; the permanent magnet groups are two groups, and the two groups of permanent magnet groups are respectively positioned on two sides of the conductor in the axial direction; the N pole and the S pole in each permanent magnet group are arranged on two sides of the rotating shaft in the radial direction; the arrangement positions of the N pole and the S pole in the two groups of permanent magnet groups are opposite;

the cooling module further comprises a cooling chamber arranged in the shell, one end of the rotating shaft is located in the cooling chamber, and a cooling liquid inlet and a cooling liquid outlet which are communicated with the cooling chamber are formed in the shell.

2. The liquid metal cooling-based electric spindle of claim 1, wherein the cooling circulation channel comprises a central flow channel and a plurality of outer flow channels, wherein an axial direction of the central flow channel coincides with an axial direction of the rotating shaft; two ends of the conductor respectively extend into the central flow passage in the radial direction; a plurality of outer side runners are uniformly distributed along the circumferential direction of the rotating shaft; every outside runner all follows the axis direction of pivot extends, and the both ends of every outside runner equally divide respectively through radial runner with the both ends intercommunication of center runner.

3. The liquid metal cooling-based electric spindle of claim 2, wherein the number of the outer flow channels is four, and an included angle between two adjacent outer flow channels is 90 degrees.

4. The liquid metal cooling-based electric spindle of claim 1, wherein the conductor is a wire.

5. The liquid metal cooling based electric spindle of claim 1, wherein both ends of the rotating shaft are fixed by a front bearing assembly and a rear bearing assembly respectively, the front bearing assembly and the rear bearing assembly are installed in the housing, and the rear bearing assembly and a rear end cover of the housing together form the cooling chamber.

6. The liquid metal cooling-based electric spindle according to claim 1, wherein mounting grooves for mounting the N pole and the S pole of the permanent magnet group are provided on the rotating shaft.

7. The liquid metal cooling-based electric spindle of claim 2, wherein a groove for installing the conductor is formed in the rotating shaft, and two ends of the groove are respectively communicated with the central flow channel through radial channels.

8. A high speed asynchronous machine comprising an electric spindle based on liquid metal cooling according to any of claims 1 to 7.

Technical Field

The invention relates to an electric spindle, in particular to an electric spindle based on liquid metal cooling and a high-speed asynchronous motor.

Background

In high-speed precision machining, machining errors caused by thermal deformation account for up to 40-70%. The high-speed electric spindle is used as a core component of the numerical control machine tool and is directly related to the processing precision which can be achieved by the numerical control machine tool. Due to the limitation of structural factors of the electric spindle, heat generated by the motor and the bearing is accumulated on the rotating shaft and cannot be effectively led out in time, so that temperature rise and deformation are caused, the matching size of the spindle is changed, and the machining precision is finally influenced.

The heat source of the electric spindle mainly comprises a motor and a bearing. The heat generated by the bearing is mainly caused by the friction between the rolling body and the inner and outer rings; the heat generated by the motor mainly comprises stator winding copper loss heating, rotating shaft iron loss heating and heat generated by friction of surrounding air when the rotating shaft rotates at a high speed, wherein the stator heating accounts for 2/3 of the total heating value, and the rotating shaft heating accounts for 1/3.

At present, the successful application of novel lubrication cooling technologies such as oil-gas, oil-fog and the like and novel supporting technologies such as air flotation, hydraulic pressure and the like greatly improves the heating problem of the bearing. The popularization of the stator spiral water (oil) sleeve solves the heating problem of the motor stator. However, because the motor rotating shaft is in a high-speed rotating state, no effective cooling method exists, and the cooling method is a thermal weak link of a high-speed electric spindle system.

The existing shaft core cooling method is characterized in that high-pressure cooling fluid is introduced into a rotating shaft core cooling flow channel by a rotary sealing joint to realize high-efficiency cooling. However, the method needs to overcome the problem of rotary dynamic sealing, and the great increase of the rotating speed can lead to the rapid increase of the difficulty of the rotary sealing, thus leading to the increase of the cooling cost and the reduction of the reliability. The heat pipe is introduced into the electric spindle shaft core and the heat of the electric spindle is led out by utilizing the structural characteristics of the heat pipe or the thermosiphon, but the heat pipe generates pressure difference by depending on temperature difference to drive the internal liquid to flow and transfer heat, so that the temperature of the shaft core is overhigh when the heat flow density is high.

Therefore, the spindle system of the electric spindle is still a thermal weak link of the high-speed electric spindle, and the efficient cooling of the electric spindle is a great challenge. The heat generated by the motor rotating shaft and the bearing is continuously accumulated to form an 'external cold and internal heat' temperature distribution pattern, so that the heat deformation is caused, and the improvement of the processing precision of the numerical control machine tool is seriously restrained.

Therefore, how to realize the efficient cooling of the shaft core of the high-speed electric spindle is the key for further improving the machining precision of the numerical control machine tool.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides the electric spindle based on liquid metal cooling, the electric spindle can rapidly guide out the heat of the axis of the electric spindle, effectively control the temperature rise of the axis of the electric spindle, reduce the thermal deformation and improve the processing precision. Meanwhile, the electric spindle also has the advantages of high reliability and low cost.

A second object of the present invention is to provide a high-speed asynchronous motor using the above-mentioned motorized spindle.

The technical scheme for solving the technical problems is as follows:

an electric spindle based on liquid metal cooling comprises a shell, a stator, a rotor, a rotating shaft and a cooling module, wherein the stator, the rotor and the rotating shaft are arranged in the shell, the cooling module is used for cooling the rotating shaft,

the rotating shaft is positioned in the rotor, a cooling circulation channel is arranged in the rotating shaft, the cooling circulation channel extends along the axis direction of the rotating shaft, and liquid metal is filled in the cooling circulation channel;

the cooling module comprises conductors and permanent magnet groups, wherein the conductors are arranged on the rotating shaft in at least two groups and are symmetrically arranged on two sides of the rotating shaft in the radial direction, each group of conductors extends along the axial direction of the rotating shaft, and two ends of each conductor respectively extend into two sides of the cooling circulation channel; the permanent magnet groups are two groups, and the two groups of permanent magnet groups are respectively positioned on two sides of the conductor in the axial direction; the N pole and the S pole in each permanent magnet group are arranged on two sides of the rotating shaft in the radial direction; the arrangement positions of the N pole and the S pole in the two groups of permanent magnet groups are opposite;

the cooling module further comprises a cooling chamber arranged in the shell, one end of the rotating shaft is located in the cooling chamber, and a cooling liquid inlet and a cooling liquid outlet which are communicated with the cooling chamber are formed in the shell.

The working principle of the electric spindle based on liquid metal cooling is as follows:

when the cooling device works, a cooling liquid inlet and a cooling liquid outlet in the shell are respectively communicated with corresponding pipelines, and cooling liquid is introduced into the cooling chamber through the cooling liquid supply device. In the process of rotating the rotating shaft, because of the existence of the slip ratio of the asynchronous motor, the rotating speed difference exists between the rotating shaft of the motor and the magnetic field of the stator of the motor, so that the conductor arranged on the rotating shaft continuously cuts the magnetic field formed by the stator of the motor and an induced current is generated in the conductor; the generated induced current flows through the cold cutting circulation channel through the conductor, and the liquid metal in the cooling circulation channel is acted by ampere force in the magnetic field range of the permanent magnet groups on the two sides of the rotating shaft. Because the two groups of conductors are symmetrically arranged, in the rotating process of the rotating shaft, the moving directions of the two groups of conductors relative to the magnetic field of the motor stator are opposite, so that the directions of induced currents generated in the two groups of conductors are opposite, and the directions of magnetic fields generated by the two groups of permanent magnet groups are also opposite because the arrangement positions of N poles and S poles of the permanent magnet groups on two sides of the rotating shaft are also opposite, so that the ampere force applied to the liquid metal in the magnetic field range of the two groups of permanent magnet groups is the same, and the liquid metal circularly flows in the cooling circulation channel along the same direction under the action of the same ampere force; when the liquid metal flows to the end part of the rotating shaft positioned in the cooling chamber, the liquid metal and the cooling liquid in the cooling chamber exchange heat, so that the temperature inside the rotating shaft is reduced; and the cooling liquid which completes heat exchange in the cooling chamber is led out through the cooling liquid outlet.

Preferably, the cooling circulation channel includes a central flow channel and a plurality of outer flow channels, wherein an axial direction of the central flow channel coincides with an axial direction of the rotating shaft; two ends of the conductor respectively extend into the central flow passage in the radial direction; a plurality of outer side runners are uniformly distributed along the circumferential direction of the rotating shaft; every outside runner all follows the axis direction of pivot extends, and the both ends of every outside runner equally divide respectively through radial runner with the both ends intercommunication of center runner.

Preferably, the number of the outer side flow channels is four, and an included angle between two adjacent outer side flow channels is 90 degrees.

Preferably, the conductor is a wire.

Preferably, both ends of the rotating shaft are respectively fixed through a front bearing assembly and a rear bearing assembly, the front bearing assembly and the rear bearing assembly are installed in the housing, and the rear bearing assembly and a rear end cover of the housing together form the cooling chamber.

Preferably, the rotating shaft is provided with mounting grooves for mounting the N pole and the S pole of the permanent magnet group.

Preferably, the rotating shaft is provided with a groove for installing the conductor, and two ends of the groove are respectively communicated with the central flow channel through radial channels.

A high-speed asynchronous motor comprises the electric spindle based on liquid metal cooling.

Compared with the prior art, the invention has the following beneficial effects:

1. the electric spindle based on liquid metal cooling is internally provided with a cooling circulation flow channel and liquid metal is placed in the cooling circulation flow channel; in the process of rotating the rotating shaft, the two groups of conductors on the two sides of the rotating shaft are opposite in moving direction relative to the magnetic field of the motor stator to generate opposite induced currents, and the arrangement positions of the N poles and the S poles of the permanent magnet groups on the two sides of the rotating shaft are also opposite, so that the directions of the magnetic fields generated by the two groups of permanent magnet groups are also opposite, the ampere force applied to the liquid metal in the magnetic field range of the two groups of permanent magnet groups is the same, and the liquid metal circularly flows in the cooling circulation channel along the same direction under the action of the same ampere force; when the liquid metal flows to the end part of the rotating shaft positioned in the cooling chamber, the liquid metal exchanges heat with the cooling liquid in the cooling chamber, and the cooling liquid which completes the heat exchange in the cooling chamber is led out through the cooling liquid outlet. Therefore, heat generated by the motor rotating shaft and the bearing can be quickly transferred to the end part of the rotating shaft, and cooling is carried out by cooling liquid in the cooling chamber, so that the efficient cooling process of the heat of the axis of the electric spindle is completed.

2. The electric spindle based on liquid metal cooling utilizes the magnetic field of the motor stator to drive the liquid metal to circularly flow in the cooling circulation channel, does not need to additionally arrange a power element, can utilize the heat transfer performance of the liquid metal far higher than water, realizes the quick conduction of the heat of the axis of the electric spindle, effectively controls the temperature rise of the axis of the electric spindle, reduces the thermal deformation and improves the processing precision. Meanwhile, the electric spindle has the advantages of high reliability and low cost.

Drawings

Fig. 1 is a schematic structural diagram of an electric spindle based on liquid metal cooling according to the present invention.

Fig. 2 is a cross-sectional view of the shaft at a-a.

Fig. 3 is a diagram of the magnetic field distribution in the electric spindle based on liquid metal cooling according to the present invention.

Fig. 4 is a schematic diagram of the circulation flow of liquid metal.

Detailed Description

The present invention will be described in further detail with reference to examples and drawings, but the present invention is not limited thereto.

Example 1

Referring to fig. 1 to 4, the liquid metal cooling-based electric spindle of the present invention includes a housing 2, a stator 3 disposed in the housing 2, a rotor 4, a rotating shaft 6, and a cooling module for cooling the rotating shaft 6, wherein,

a squirrel-cage-shaped cooling circulation channel is arranged in the rotating shaft 6, extends along the axial direction of the rotating shaft 6, is filled with liquid metal, and comprises a central flow channel 12 and a plurality of outer flow channels 13, wherein the axial direction of the central flow channel 12 is overlapped with the axial direction of the rotating shaft 6; two ends of the lead 15 respectively extend into the central flow passage 12 in the radial direction; a plurality of outer flow channels 13 are uniformly distributed along the circumferential direction of the rotating shaft 6; each outer flow channel 13 extends along the axial direction of the rotating shaft 6, and two ends of each outer flow channel 13 are respectively communicated with two ends of the central flow channel 12 through radial flow channels 11;

in this embodiment, the number of the outer side flow channels 13 is four, and an included angle between two adjacent outer side flow channels 13 is 90 degrees;

the cooling module comprises a conductor 15 arranged on the shaft 6 and a set of permanent magnets (14, 16), wherein,

the number of the leads 15 is at least two, and the leads are symmetrically arranged on two sides of the rotating shaft 6 in the radial direction, each group of the leads 15 extends along the axial direction of the rotating shaft 6, and two ends of each lead 15 respectively extend into two sides of the cooling circulation channel; a groove for installing the lead 15 is formed in the rotating shaft 6, and two ends of the groove are respectively communicated with the central flow channel 12 through radial channels;

the two groups of permanent magnet groups (14, 16) are respectively positioned at two sides of the axial direction of the lead 15; wherein, the N pole and the S pole in each permanent magnet group (14 or 16) are arranged at two sides of the radial direction of the rotating shaft 6; the rotating shaft 6 is provided with mounting grooves for mounting the N pole and the S pole of the permanent magnet groups (14 and 16); the arrangement positions of the N pole and the S pole in the two groups of permanent magnet groups (14, 16) are opposite; namely, the magnetic field directions of the permanent magnet group 14 and the permanent magnet group 16 are opposite;

the cooling module further comprises a cooling chamber 9 arranged in the shell 2, one end of the rotating shaft 6 is located in the cooling chamber 9, and a cooling liquid inlet 7 and a cooling liquid outlet 10 which are communicated with the cooling chamber 9 are arranged on the shell 2.

Referring to fig. 1 to 4, both ends of the rotating shaft 6 are fixed by a front bearing assembly 1 and a rear bearing assembly 5 respectively, the front bearing assembly 1 and the rear bearing assembly 5 are installed in the housing 2, and the rear bearing assembly 5 and a rear end cover 8 of the housing 2 together form the cooling chamber 9.

Referring to fig. 1-4, the working principle of the electric spindle based on liquid metal cooling of the present invention is:

in fig. 4, B in the left and right two dotted frames represents the magnetic field direction of the permanent magnet groups (14, 16), and B in the middle dotted frame represents the magnetic field direction of the motor stator 3; i represents the direction of current flow in wire 15, v represents the direction of movement of wire 15, and F represents the direction of the ampere force.

In operation, the cooling liquid inlet 7 and the cooling liquid outlet 10 in the housing 2 are respectively communicated with corresponding pipelines, and cooling liquid is introduced into the cooling chamber 9 through a cooling liquid supply device. In the process of rotating the rotating shaft 6, because of the existence of the slip ratio of the asynchronous motor, the rotating speed difference exists between the rotating shaft 6 of the motor and the magnetic field of the stator 3 of the motor, so that the conducting wire 15 arranged on the rotating shaft 6 continuously cuts the magnetic field formed by the stator 3 of the motor and an induced current is generated in the conducting wire 15; the induced current is conducted through the central flow passage 12 by the conducting wire 15, and the liquid metal in the central flow passage 12 is acted upon by an ampere force in the magnetic field range of the permanent magnet groups (14, 16) on both sides of the rotating shaft 6. Because the two groups of conducting wires 15 are symmetrically arranged, in the process of rotating the rotating shaft 6, the moving directions of the two groups of conducting wires 15 relative to the magnetic field of the motor stator 3 are opposite, the directions of induced currents generated in the two groups of conducting wires 15 are opposite, and the arrangement positions of N poles and S poles of the permanent magnet groups (14, 16) on two sides of the rotating shaft 6 are also opposite, so that the directions of magnetic fields generated by the two groups of permanent magnet groups (14, 16) are also opposite, so that the ampere force applied to the liquid metal in the magnetic field range of the two groups of permanent magnet groups (14, 16) is the same, under the action of the same ampere force, the liquid metal in the central flow passage 12 is driven to flow in a 'squirrel-cage-shaped' loop formed by the central flow passage 12, the radial flow passage 11 and the outer flow passage 13 together, and further the heat generated by the motor rotating shaft 6 and the bearing is rapidly transferred to the end part of the rotating shaft 6, and is cooled by the cooling liquid in the cooling chamber 9, and finishing the efficient cooling process of the heat of the axis of the electric spindle. After the heat exchange is completed, the cooling fluid in the cooling chamber 9, which has completed the heat exchange, is discharged through the cooling fluid outlet 10.

Example 2

The high-speed asynchronous motor comprises the electric spindle based on liquid metal cooling.

The above description is a preferred embodiment of the present invention, but the present invention is not limited to the above description, and any other changes, modifications, substitutions, blocks and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and they are included in the scope of the present invention.