High torque density design method of motorized spindle

Abstract

The invention provides a high-torque-density design method for an electric spindle, and belongs to the technical field of electric spindle design, and the method comprises the following steps: step 1, carrying out architecture setting on each part of the electric spindle to obtain a basic mechanism of the electric spindle; 2, performing complete machine design according to the basic architecture, and performing simulation modeling; and 3, designing a plurality of physical field characteristic verifications, completing the design after each characteristic is verified to be qualified, and returning to the step 1 and the step 2 to carry out design adjustment until all physical field characteristics are verified and the design is completed if some characteristics are verified to be unqualified. The torque density of the motorized spindle is improved, the output torque under the same size is greatly improved, miniaturization and light weight of the motorized spindle are achieved, installation and maintenance are convenient, the overall weight is reduced, the high performance of the motorized spindle is enhanced, higher efficiency and better dynamic response and reliability are achieved, and through physical field characteristic verification, the reliability of the motorized spindle is improved. Verification for each characteristic may be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of electric spindle design, and particularly to a high torque density design method for an electric spindle. Background Art

[0002] With the growth of the demand for high-performance power transmission devices in modern manufacturing, the electric spindle, as the core component of processing equipment such as numerically controlled machine tools, its performance directly affects the machining accuracy and production efficiency. Traditional electric spindles have deficiencies in torque density, which limits their application scope and development potential. To overcome these problems, there is an urgent need to develop a new design method to improve the torque density of the electric spindle while ensuring its miniaturization, lightweight, and high performance. Summary of the Invention

[0003] The purpose of the present invention is to provide a high torque density design method for an electric spindle, so as to solve the technical problem of the relatively low torque density of the existing electric spindle.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0005] A high torque density design method for an electric spindle, the method comprising the following steps:

[0006] Step 1: Perform architecture setting on each component of the electric spindle according to the design index requirements to obtain the basic mechanism of the electric spindle;

[0007] Step 2: Perform overall machine design according to the basic architecture, and then perform simulation modeling;

[0008] Step 3: Design several physical field characteristic verifications. After each characteristic is verified to be qualified, the design is completed. If any characteristic verification is unqualified, return to Step 1 and Step 2 for design adjustment until all physical field characteristic verifications are completed and the design is finished.

[0009] Further, in Step 1, the architecture design of each component includes stator structure, stator material and slot combination, rotor structure, rotor structure permanent magnet material, support system, support structure bearing selection, cooling system, and cooling medium and architecture design. According to the initial design scheme, each component is given an initial structure and the corresponding selected material.

[0010] Furthermore, the specific process of simulation modeling in Step 2 is as follows: perform structural mechanics static and dynamic analysis to calculate the stress distribution and deformation under static load, simulate the vibration characteristics based on the inertial force and periodic excitation caused by rotation, conduct magnetic field modeling, establish the electromagnetic field model inside the permanent magnet synchronous motor based on Maxwell's equations, calculate the induced electromotive force and current distribution in the winding, and then derive the torque output. Establish heat conduction and convection, analyze the heat transfer path from the heat source to the surrounding environment according to the thermal physical properties of the material, simulate the flow state of the coolant in the pipeline of the transfer path and its heat exchange effect, set the position and type of virtual sensors for collecting data on the operating state of the motor, and provide data reference through feedback.

[0011] Furthermore, in Step 3, the physical field characteristics include magnetic characteristics, loss characteristics, temperature rise characteristics, rotor strength, and critical speed.

[0012] Furthermore, when the magnetic characteristics verification fails, adjust the stator structure, stator material and slot combination, rotor structure, rotor structure magnet material, permanent magnet material, and air gap length; when the loss characteristics are unqualified, adjust the stator structure, stator material and slot combination, rotor structure, rotor structure magnet material, support system, support structure bearing selection, permanent magnet material, and air gap length; when the temperature rise characteristics are unqualified, adjust the cooling system, cooling medium and architecture, stator material, rotor material, and permanent magnet material; when the rotor strength is unqualified, adjust the rotor structure, stator material, rotor material, permanent magnet position, and permanent magnet material; when the critical speed is unqualified, adjust the rotor structure, support system, support position and stiffness. Then design the optimal solution equation, set the characteristic data, and then obtain the relevant data of each component of the optimal solution electric spindle.

[0013] The electric spindle includes a spindle mechanism, a heat dissipation component, and an electric drive component. The heat dissipation component is arranged at one end of the spindle mechanism and is embedded in the spindle mechanism. The electric drive component is arranged at one end of the heat dissipation component and passes through the spindle mechanism and the heat dissipation component.

[0014] Furthermore, the spindle mechanism includes a housing, a front bearing mount, a front bearing, a motor assembly, a rotating shaft, a rear bearing, and a rear bearing mount. The front bearing mount and the rear bearing mount are respectively arranged at both ends of the housing. The motor assembly is arranged inside the housing. The front bearing is arranged inside the front bearing mount. The rear bearing is arranged inside the rear bearing mount. The rotating shaft passes through the inside of the motor assembly and is respectively arranged on the front bearing and the rear bearing at both ends.

[0015] Furthermore, the motor assembly includes a stator assembly, a rotor assembly, and a sheath. The stator assembly is arranged outside the rotor assembly. The sheath is arranged between the stator assembly and the rotor assembly. The rotating shaft is arranged inside the rotor assembly.

[0016] Further, an encoder is provided on the rotating shaft. The rotating shaft is a hollow rotating shaft, and a chuck assembly is provided at the front end of the rotating shaft.

[0017] Further, the sheath is a carbon fiber sheath, and both the front bearing and the rear bearing are magnetic levitation bearings.

[0018] Further, the heat dissipation assembly includes a heat dissipation box and a cooling structure. The heat dissipation box is provided at both ends of the cooling structure, and the cooling structure is provided inside the housing of the stator assembly.

[0019] Further, the cooling structure is arranged as a Z-shaped annular water jacket cooling structure. The water jacket cooling structure is connected to the heat dissipation box to keep the average temperature of the motor below 60 degrees Celsius.

[0020] Further, the electric drive assembly includes a rear seat, a cylinder power component, a power ring, a mounting seat, a push rod release mechanism, and a push rod. The power ring is arranged on the cylinder power component. The push rod release mechanism is connected to the power ring and the push rod. One end of the push rod is arranged on the power ring. The mounting seat is arranged at the rear end of the cylinder power component. The rear seat is arranged on the heat dissipation assembly. The push rod release mechanism is arranged on the rear seat. The push rod passes through the rear seat and is arranged inside the rotating shaft.

[0021] Due to the adoption of the above technical solutions, the present invention has the following beneficial effects:

[0022] The present invention improves the torque density of the motorized spindle, greatly increases the output torque under the same volume, realizes the miniaturization and lightweight of the motorized spindle, facilitates installation and maintenance, reduces the overall weight, and enhances the high performance of the motorized spindle, including higher efficiency, better dynamic response and reliability. Through the verification of the physical field characteristics, it is possible to verify each characteristic and obtain the optimal design parameter data of the motorized spindle. Description of the Drawings

[0023] Figure 1 is the flowchart of the method of the present invention;

[0024] Figure 2 is the schematic structural diagram of the motorized spindle of the present invention. Detailed Embodiments

[0025] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the following preferred embodiments are given with reference to the accompanying drawings to further elaborate on the present invention in detail. However, it should be noted that many details listed in the specification are only for enabling the reader to have a thorough understanding of one or more aspects of the present invention, and these aspects of the present invention can be implemented even without these specific details.

[0026] As Figure 1 shown, a high torque density design method for a motorized spindle, the method includes the following steps:

[0027] Step 1: Set up the architecture of each component of the motorized spindle according to the design index requirements to obtain the basic mechanism of the motorized spindle. The architectural design of each component includes stator structure, stator material and slot combination, rotor structure, rotor structure permanent magnet material, support system, support structure bearing selection, cooling system, and cooling medium and architectural design. According to the initial design scheme, initial structures and corresponding selected materials are assigned to each component.

[0028] Step 2: Conduct the overall machine design based on the basic architecture and then perform simulation modeling. Conduct structural mechanics static and dynamic analyses to calculate the stress distribution and deformation under static loads. Based on the inertial forces and periodic excitations caused by rotation, simulate the vibration characteristics. Conduct magnetic field modeling, and based on Maxwell's equations, establish the electromagnetic field model inside the permanent magnet synchronous motor to calculate the induced electromotive force and current distribution in the windings, and then derive the torque output. Establish heat conduction and convection, and based on the thermal physical properties of the materials, analyze the heat transfer path from the heat source to the surrounding environment, simulate the flow state of the coolant in the pipes of the transfer path and its heat exchange effect, set the position and type of virtual sensors for collecting data on the operating state of the motor, and provide data reference through feedback.

[0029] Step 3: Design several physical field characteristic verifications. After each characteristic is verified to be qualified, the design is completed. If any characteristic verification fails, return to Step 1 and Step 2 for design adjustments until all physical field characteristic verifications are completed and the design is finalized. Physical field characteristics include magnetic characteristics, loss characteristics, temperature rise characteristics, rotor strength, and critical speed. When the magnetic characteristics verification fails, adjust the stator structure, stator material and slot combination, rotor structure, rotor structure permanent magnet material, permanent magnet material, and air gap length. When the loss characteristics are unqualified, adjust the stator structure, stator material and slot combination, rotor structure, rotor structure permanent magnet material, support system, support structure bearing selection, permanent magnet material, and air gap length. When the temperature rise characteristics are unqualified, adjust the cooling system, cooling medium and architecture, stator material, rotor material, and permanent magnet material. When the rotor strength is unqualified, adjust the rotor structure, stator material, rotor material, permanent magnet position, and permanent magnet material. When the critical speed is unqualified, adjust the rotor structure, support system, support position, and stiffness. Then design the optimal solution equation, set the characteristic data, and obtain the relevant data of each component of the motorized spindle with the optimal solution.

[0030] Such as Figure 2As shown in the figure, the electric spindle includes a spindle mechanism, a heat dissipation component, and an electric drive component. The heat dissipation component is arranged at one end of the spindle mechanism and is embedded in the spindle mechanism. The electric drive component is arranged at one end of the heat dissipation component and passes through the spindle mechanism and the heat dissipation component. The main function of the spindle mechanism is to drive rotation. The main function of the heat dissipation component is to dissipate heat inside the spindle mechanism. Then, the main function of the electric drive component is to realize the forward and backward movements.

[0031] In the embodiment of the present invention, the spindle mechanism includes a housing 1, a front bearing mount 2, a front bearing 3, a motor assembly, a rotating shaft 5, a rear bearing 11, and a rear bearing mount 12. The front bearing mount 2 and the rear bearing mount 12 are respectively arranged at both ends of the housing 1. The motor assembly is arranged inside the housing 1. The front bearing 3 is arranged inside the front bearing mount 2. The rear bearing 11 is arranged inside the rear bearing mount 12. The rotating shaft 5 passes through the inside of the motor assembly and is respectively arranged on the front bearing 3 and the rear bearing 11 at both ends. The motor assembly includes a stator assembly 7, a rotor assembly 8, and a sheath 6. The stator assembly 7 is arranged outside the rotor assembly 8. The sheath 6 is arranged between the stator assembly 7 and the rotor assembly 8. The rotating shaft 5 is arranged inside the rotor assembly 8.

[0032] In the embodiment of the present invention, an encoder 10 is arranged on the rotating shaft 5. The rotating shaft 5 is a hollow rotating shaft, and a chuck assembly 4 is arranged at the front end of the rotating shaft 5.

[0033] In the embodiment of the present invention, the sheath 6 is a carbon fiber sheath, and both the front bearing 3 and the rear bearing 11 are magnetic levitation bearings. The interference fit between the rotor carbon fiber sheath and the permanent magnet is 0.06 mm, and the force on the permanent magnet is much lower than its tensile strength (the tensile strength of neodymium iron boron is in the range of 80 - 140 MPa).

[0034] In the embodiment of the present invention, the heat dissipation component includes a heat dissipation box 9 and a cooling structure. The heat dissipation box 9 is arranged at both ends of the cooling structure, and the cooling structure is arranged inside the housing of the stator assembly 7.

[0035] In the embodiment of the present invention, the cooling structure is set as a Z-shaped annular water jacket cooling structure. The water jacket cooling structure is connected to the heat dissipation box 9 to keep the average temperature of the motor below 60 degrees Celsius. By adopting the Z-shaped annular water jacket cooling structure for the stator housing and optimizing the size of the water channel, heat can be taken away with the highest efficiency.

[0036] The electric drive component includes a rear seat 13, a cylinder power component 14, a power ring 15, a mounting seat 16, a push rod release mechanism 17, and a push rod 18. The power ring 15 is arranged on the cylinder power component 14. The push rod release mechanism 17 is connected to the power ring 15 and the push rod 18. One end of the push rod 18 is arranged on the power ring 15. The mounting seat 16 is arranged at the rear end of the cylinder power component 14. The rear seat 13 is arranged on the heat dissipation component. The push rod release mechanism 17 is arranged on the rear seat 13. The push rod 18 passes through the rear seat 13 and is arranged inside the rotating shaft 5.

[0037] When designing the electric spindle, several physical field co-simulations are adopted, including electromagnetic design, heat dissipation design and mechanical mechanics simulation design. At the same time, the methods of harmonic pole cutting and harmonic injection are used to improve the torque density of the permanent magnet motor system. The coupling relationship between the motor and the controller is fully considered to achieve high-speed precision dynamic control and improve the overall efficiency of the motor system. Through refined analysis of iron loss and optimization of dimensions, the efficiency of the electric spindle is improved to create a brand of high-efficiency and energy-saving electric spindles.

[0038] The rated voltage (Vdc) of this electric spindle is 208, the continuous power (kW) is 2.0, the maximum dynamic runout (μm) is 7 (150,000 rpm), the continuous torque (Nm) is 0.1273, the continuous load (Nm) is 2000, the rated speed (rpm) is 150,000, the maximum speed (rpm) is 160,000, the operating temperature range (°C) is -40 to +65, the locked-rotor torque (Nm) is 7.47, the maximum fixture torque (Nm) is 2.3, the maximum leakage current (mA) is 0.01, the reference mass (kg) is 2.5, and the reference external dimensions (mm) are Φ50×200.

[0039] Matters not covered by this invention are well-known technologies.

[0040] The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A high torque density design method for an electric spindle, characterized by: The method comprises the following steps: Step 1: According to the design index requirements, the various components of the electric spindle are structured to obtain the basic structure of the electric spindle; Step 2: Design the whole machine according to the basic architecture, and then perform simulation modeling; Step 3: Design several physical field characteristic verifications. After each characteristic is verified to be qualified, the design is completed. If any characteristic verification fails, return to steps 1 and 2 to adjust the design until all physical field characteristics are verified and the design is completed.

2. The high torque density design method of an electric spindle according to claim 1, characterized in that: In step 1, the architecture design of each component includes stator structure, stator material and slot matching, rotor structure, rotor structure magnetic steel material, support system, support structure bearing selection, cooling system and cooling medium and architecture design. According to the initial design plan, each component is given an initial structure and corresponding selected materials.

3. The high torque density design method of an electric spindle according to claim 1, characterized in that: The specific process of simulation modeling in step 2 is: static and dynamic analysis of structural mechanics, calculation of stress distribution and deformation under static load, simulation of vibration characteristics according to the inertial force and periodic excitation caused by rotation, magnetic field modeling, and establishment of electromagnetic field model inside the permanent magnet synchronous motor based on Maxwell equations. The induced electromotive force and current distribution in the winding are calculated to derive the torque output, and heat conduction and convection are established. According to the thermophysical parameters of the material, the heat transfer path from the heat source to the surrounding environment is analyzed, the flow state of the coolant in the pipe of the transfer path and its heat exchange effect are simulated, and the position and type of the virtual sensor are set to collect data on the motor operation status and provide data reference through feedback.

4. The high torque density design method of an electric spindle according to claim 1, characterized in that: In step 3, the physical field characteristics include magnetic characteristics, loss characteristics, temperature rise characteristics, rotor strength and critical speed.

5. The high torque density design method of an electric spindle according to claim 4, characterized in that: When the magnetic property verification fails, adjust the stator structure, stator material and slot matching, rotor structure, rotor structure magnetic steel material, permanent magnet material and air gap length; when the loss characteristic fails, adjust the stator structure, stator material and slot matching, rotor structure, rotor structure magnetic steel material, support system, support structure bearing selection, permanent magnet material and air gap length; when the heating characteristic fails, adjust the cooling system, cooling medium and structure, stator material, rotor material and permanent magnet material; when the rotor strength fails, adjust the rotor structure, stator material, rotor material, permanent magnet position and permanent magnet material; when the critical speed fails, adjust the rotor structure, support system, support position and stiffness, and then design the optimal solution equation, set the characteristic data, and then obtain the relevant data of each component of the electric spindle with the optimal solution.

6. The high torque density design method of an electric spindle according to claim 4, characterized in that: It includes a spindle mechanism, a heat dissipation component and an electric drive component. The heat dissipation component is arranged at one end of the spindle mechanism and embedded in the spindle mechanism. The electric drive component is arranged at one end of the heat dissipation component and passes through the spindle mechanism and the heat dissipation component. The spindle mechanism comprises a housing (1), a front bearing mounting seat (2), a front bearing (3), a motor assembly, a rotating shaft (5), a rear bearing (11) and a rear bearing mounting seat (12); the front bearing mounting seat (2) and the rear bearing mounting seat (12) are respectively arranged at two ends of the housing (1); the motor assembly is arranged inside the housing (1); the front bearing (3) is arranged inside the front bearing mounting seat (2); the rear bearing (11) is arranged inside the rear bearing mounting seat (12); the rotating shaft (5) passes through the interior of the motor assembly, and its two ends are respectively arranged on the front bearing (3) and the rear bearing (11).

7. The high torque density design method of an electric spindle according to claim 6, characterized in that: The motor assembly comprises a stator assembly (7), a rotor assembly (8) and a sheath (6), wherein the stator assembly (7) is arranged outside the rotor assembly (8), the sheath (6) is arranged between the stator assembly (7) and the rotor assembly (8), and the rotating shaft (5) is arranged inside the rotor assembly (8); An encoder (10) is arranged on the rotating shaft (5); the rotating shaft (5) is a hollow shaft; and a chuck assembly (4) is arranged at the front end of the rotating shaft (5).

8. The high torque density design method of an electric spindle according to claim 7, characterized in that: The sheath (6) is a carbon fiber sheath, and the front bearing (3) and the rear bearing (11) both use magnetic bearings.

9. The high torque density design method of an electric spindle according to claim 6, characterized in that: The heat dissipation assembly comprises a heat dissipation box (9) and a cooling structure, wherein the heat dissipation box (9) is arranged at both ends of the cooling structure, and the cooling structure is arranged in a housing of the stator assembly (7); The cooling structure is arranged as a Z-shaped annular water jacket cooling structure, and the water jacket cooling structure is connected to a heat sink (9) to keep the average temperature of the motor below 60 degrees Celsius.

10. The high torque density design method of an electric spindle according to claim 6, characterized in that: The electric drive assembly comprises a rear seat (13), a cylinder power member (14), a power ring (15), a mounting seat (16), a push rod release mechanism (17) and a push rod (18); the power ring (15) is arranged on the cylinder power member (14); the push rod release mechanism (17) is connected to the power ring (15) and the push rod (18); one end of the push rod (18) is arranged on the power ring (15); the mounting seat (16) is arranged at the rear end of the cylinder power member (14); the rear seat (13) is arranged on the heat dissipation assembly; the push rod release mechanism (17) is arranged on the rear seat (13); the push rod (18) passes through the rear seat (13) and is arranged in the rotating shaft (5).

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