High-overload-resistant and high-strength-magnetism permanent magnet direct current motor

Abstract

The invention relates to the technical field of permanent-magnet direct-current brushless slotless motors, in particular to a permanent-magnet direct-current motor resistant to high overload and high in magnetism, which comprises a front cover assembly used for buffering and damping, heat dissipation and cooling and magnetic shielding; the stator assembly is connected with the front cover assembly, the rotor assembly and the sensor assembly and used for providing a magnetic field, driving the rotor assembly to rotate, dissipating heat generated by the motor and meanwhile providing mechanical support; the rotor assembly is connected with the front cover assembly, the stator assembly, the sensor assembly and the rear cover assembly, and is used for interacting with a magnetic field generated by the winding, driving the motor to rotate, bearing mechanical stress, controlling temperature and resisting magnetic interference; the sensor assembly is used for detecting the position and the magnetic field of the rotor assembly and converting the position and the magnetic field of the rotor assembly into electric signals; and the rear cover assembly is used for providing mechanical support for the motor and protecting internal parts of the motor. The permanent magnet direct current brushless slotless motor improves the capability of resisting high overload and high magnetism.

Description

Technical Field

[0001] The invention relates to the technical field of permanent magnet direct current brushless slotless motors, and in particular to a permanent magnet direct current motor capable of resisting high overload and high magnetic strength. Background Art

[0002] At present, many weapon models use permanent magnet DC brushless motors mainly imported from abroad, which has a great disadvantage for military products. The permanent magnet DC brushless motors imported from abroad are industrial products. There are high technical risks in using them in military products. When the products are delivered, only the general parameters in the product catalog are provided, and the certificates, test data, test status, product resumes and other relevant information required for military products are not provided. The technical status is imperfect, which causes a great waste of manpower, material resources, time and other resources for the later product use. Therefore, increasing the investment in the research and development of military hollow cup motor products, improving the design level, mastering the core technology, and owning independent intellectual property rights have become the inevitable trend of the development of military hollow cup motors.

[0003] Chinese Patent Publication No.: CN110994887A discloses a permanent magnet DC brushless slotless motor, including a reduction box and a motor box, wherein a first transmission wheel and a second transmission wheel are arranged in the reduction box, a driving motor is arranged in the motor box, and the driving motor cooperates with the first transmission wheel in transmission, a first opening is arranged on the reduction box, a first cover plate is arranged in the first opening, a first through hole is arranged on one side wall of the reduction box, a second through hole is arranged on the other side wall, a first connecting shaft is penetrated in the first through hole, a second connecting shaft is penetrated in the second through hole, a first limit assembly is arranged in the first through hole, and a second limit assembly is arranged in the second through hole; when maintaining the transmission wheel, the first cover plate is opened, and the first connecting shaft and the second connecting shaft are moved along the inner walls of the first through hole and the second through hole; it can be seen that this scheme is difficult to improve the ability of the permanent magnet DC brushless slotless motor to resist high overload and high-strength magnetism. Summary of the invention

[0004] To this end, the present invention provides a permanent magnet DC motor capable of resisting high overload and high magnetic strength, so as to overcome the problem of low ability of permanent magnet DC brushless slotless motor to resist high overload and high magnetic strength in the prior art.

[0005] To achieve the above object, the present invention provides a permanent magnet DC motor capable of resisting high overload and high magnetic strength, comprising:

[0006] A front cover assembly, which is connected to the stator assembly and the rotor assembly and is used for buffering and shock absorption, heat dissipation and cooling, and magnetic shielding;

[0007] The stator assembly is connected to the front cover assembly, the rotor assembly and the sensor assembly, and is used to provide a magnetic field, drive the rotor assembly to rotate, dissipate the heat generated by the generator, and provide mechanical support;

[0008] A rotor assembly, which is connected to the front cover assembly, the stator assembly, the sensor assembly and the rear cover assembly, and is used to interact with the magnetic field generated by the winding, drive the motor to rotate, and withstand mechanical stress, control temperature and resist magnetic interference;

[0009] A sensor assembly connected to the stator assembly and the rear cover assembly, for detecting the position and magnetic field of the rotor assembly and converting the position and magnetic field of the rotor assembly into electrical signals;

[0010] A rear cover assembly, which is connected to the stator assembly and the rotor assembly, and is used to provide mechanical support for the motor and protect the internal components of the motor;

[0011] Among them, the front cover and stator casing, as well as the rear cover and stator casing are connected by laser welding. In addition to the conventional deep groove ball bearings at both ends of the rotor, thrust ball bearings and disc spring structures are additionally added. The axial clearance of the motor is controlled to be between 0.01-0.03mm. The rotor magnet is made of high-performance permanent magnet NdFeB material and an adjustment slot is added to the end of the rotor shaft to adjust the magnetic field direction of the rotor magnet so that the magnetic field direction of the rotor magnet is consistent with the external strong magnetic field.

[0012] Furthermore, deep groove ball bearings are provided in the front cover assembly and the rear cover assembly, and the design parameters of the deep groove ball bearings are set as follows: radial force Fr=15 (N), axial force Fa=2 (N), journal diameter d1=4 (mm), rotation speed n=9000 (r / min), required life Lh'=50000 (h), temperature coefficient ft=1, and lubrication method is grease lubrication.

[0013] Furthermore, the stator assembly comprises:

[0014] The casing is connected to the core and is used to protect the internal components of the motor and provide mechanical support;

[0015] The iron core is connected to the casing and the insulating paper and is used to enhance the magnetic field and control the direction of the magnetic field;

[0016] The winding is connected to the insulating paper and is used for power transmission, voltage conversion and power regulation; the winding and the two ends of the iron core are sealed with epoxy glue;

[0017] Insulating paper is connected to the iron core and the winding to increase the insulation distance between the winding and the iron core.

[0018] Furthermore, in the stator assembly, the core structure is set to a slotless structure, the material is 20WTG1500 electrical cold-rolled silicon steel sheet, and it is bonded to the casing with a two-component epoxy adhesive. The insulating paper material is a 6650 composite material with a thickness of 0.15 mm, the winding material is a hot air self-adhesive wire with a temperature resistance grade of 180°C, the winding method is a diamond wire petal bonding method, the winding and the two ends of the core are sealed with epoxy adhesive, and the casing and the front and rear covers are made of stainless round steel 2Cr13.

[0019] Furthermore, the winding is trial-wound with the wire petals on a semi-automatic winding machine using a winding plate and a wire pressing plate according to the requirements of the preset drawings, and the wound wire petals are measured according to the requirements of the preset drawings, and the parameter settings of the semi-automatic winding machine are adjusted until the formed wire petals meet the requirements of the preset drawings, and the wire petals are arranged in sequence on top using a clamp, and the adjacent wire petals are bonded and fixed at the junction with a two-component epoxy glue, and then the positioning device is placed together with the wire petals on the winding bonding machine, the wire petals are continuously kept warm and pressurized, the wire petal taps are arranged and cut, and the cut wire petals are hot-pressed, and then the hot-pressed wire petals are placed on a winding machine, and the rolling mold on the rolling machine is used to perform the rolling operation to form a preliminary winding, and the preliminary winding is placed on a shaping machine for rough shaping and fine shaping in steps, a layer of single-component solid glue is evenly applied to the inner and outer surfaces of the shaped winding, and a pressure device is used to fix and press the winding, and the high temperature is maintained to form the final winding.

[0020] Furthermore, the rotor assembly comprises:

[0021] A rotating shaft connected to the magnetic steel, the front bearing retaining ring and the rear bearing retaining ring for transmitting torque and bearing bending moment;

[0022] A magnetic steel connected to the front bearing retaining ring and the rear bearing retaining ring, used to generate a magnetic field, convert electrical energy into mechanical energy, and drive the shaft to rotate;

[0023] The front bearing retaining ring is connected to the rotating shaft and is used to prevent the magnetic steel from moving on the rotating shaft. It is also used to remove weight when the rotor is dynamically balanced.

[0024] The rear bearing retaining ring is connected to the rotating shaft and is used to prevent the magnetic steel from moving on the rotating shaft. It is also used to remove weight when the rotor is dynamically balanced.

[0025] The sensor magnet is connected to the rear bearing retaining ring and is used to detect the working parameters of the permanent magnet DC motor that resists high overload and high magnetic strength.

[0026] Furthermore, in the rotor assembly, the magnetic steel material is set to N52UH sintered NdFeB magnetic steel, the length is 28 mm, the front bearing retaining ring and the rear bearing retaining ring are made of stainless round steel 316, and the shaft material is stainless round steel 2Cr13.

[0027] Furthermore, the Hall plate assembly comprises:

[0028] A Hall plate, which is connected to the Hall sensor and lead wires, and is used to detect the magnetic field using the Hall effect and convert it into a measurable electrical signal and output it;

[0029] A Hall sensor is connected to the wire loop and the Hall plate and is used to convert changes in the magnetic field into changes in electrical signals;

[0030] A wire passing ring, which is connected to a Hall sensor and is used to connect the winding to an external control system through the wire passing ring, and to fix and support the rotor winding;

[0031] Lead wires are connected to the Hall plate and are used to transmit control signals.

[0032] Furthermore, the Hall sensor is mounted on a circuit board, the wire ring material is set to be a high-temperature resistant material PEEK with a temperature resistance grade of 250°C, the copper foil width in the Hall circuit is 0.3mm, the current density is 2.38A / mm2, the copper foil thickness in the circuit board is 6 ounces, the copper foil width of the winding circuit is 0.6mm, and the current density is 15.87A / mm 2 .

[0033] Furthermore, in the permanent magnet DC motor capable of resisting high overload and high magnetic strength, the working process includes:

[0034] Step S1, when the winding in the stator assembly is energized, a magnetic field is generated around the iron core;

[0035] Step S2, when the magnetic steel in the rotor assembly interacts with the magnetic field, an electromagnetic torque is generated, thereby driving the shaft to rotate;

[0036] Step S3: the sensor assembly detects the position of the rotor assembly and the magnetic field strength, and converts the position of the rotor assembly and the magnetic field strength into electrical signals.

[0037] Compared with the prior art, the beneficial effect of the present invention is that the device continuously detects the position of the rotor through the sensor assembly, and converts the position information into an electrical signal, and adjusts the current in the stator winding according to the position information to keep the rotor rotating at a set speed and direction. During the operation of the motor, the stator assembly and the rotor assembly will generate a lot of heat. The structural design of the front cover assembly and the rear cover assembly is conducive to heat dissipation. The device also has a heat dissipation function through the stator assembly to ensure that the motor runs at an appropriate temperature. The front cover assembly, the rear cover assembly and the stator assembly jointly provide mechanical support for the motor to prevent damage to internal components. The device has a buffering and shock-absorbing effect to reduce vibration and noise during motor operation. The device uses precise magnetic field control and efficient heat dissipation design. It realizes efficient conversion between electrical energy and mechanical energy, has high structural strength, good buffering and shock absorption effect, and precise sensor feedback mechanism to ensure the stability and reliability of motor operation. Efficient energy conversion and heat dissipation design reduce energy waste. Low noise and low vibration operation characteristics also meet environmental protection requirements. Modular design makes the various components of the motor easy to disassemble and replace. The prototype of the device has been subjected to an impact environment test with a value of 15000g. After the test, all indicators of the motor are normal. In terms of the ability to resist strong magnetic fields and radio frequency electromagnetic fields, the magnetic field strength is ≥4T, the magnetic field change rate is >1875T / s, and the magnetic field strength of the external radio frequency electromagnetic environment is 25V / m at a frequency of 10kHz-2MHz, and 50V / m at a frequency of 2MHz-18GHz. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic diagram of the structure of a permanent magnet DC motor capable of resisting high overload and high magnetic strength according to the present embodiment;

[0039] Figure 2 Schematic diagram of the structure of the stator assembly of this embodiment;

[0040] Figure 3 is a schematic structural diagram of the rotor assembly of this embodiment;

[0041] Figure 4 Schematic diagram of the structure of the Hall plate assembly of this embodiment; Figure 5 This is a displacement cloud diagram of the deformation simulation result of a radial impact of 20000g applied to the motor housing under the finite element simulation of this embodiment. DETAILED DESCRIPTION

[0042] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0043] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0044] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0045] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] See also Figure 1 As shown, it is a structural schematic diagram of a permanent magnet DC motor that resists high overload and high magnetic strength in this example, and the device includes:

[0047] The front cover assembly 01 is connected to the stator assembly 02 and the rotor assembly 03 and is used for buffering, damping, heat dissipation, cooling and magnetic shielding;

[0048] The stator assembly 02 is connected to the front cover assembly 01, the rotor assembly 03 and the sensor assembly 04, and is used to provide a magnetic field, drive the rotor assembly 03 to rotate, dissipate the heat generated by the generator, and provide mechanical support;

[0049] The rotor assembly 03 is connected to the front cover assembly 01, the stator assembly 02, the sensor assembly 04 and the rear cover assembly 05, and is used to interact with the magnetic field generated by the winding, drive the motor to rotate, and withstand mechanical stress, control temperature and resist magnetic interference;

[0050] The sensor assembly 04 is connected to the stator assembly 02 and the rear cover assembly 05, and is used to detect the position and magnetic field of the rotor assembly 03, and convert the position and magnetic field of the rotor assembly 03 into electrical signals;

[0051] The rear cover assembly 05 is connected to the stator assembly 02 and the rotor assembly 03 to provide mechanical support for the motor and protect the internal components of the motor;

[0052] Among them, the front cover and stator casing, as well as the rear cover and stator casing are connected by laser welding. In addition to the conventional deep groove ball bearings at both ends of the rotor, thrust ball bearings and disc spring structures are additionally added. The axial clearance of the motor is controlled to be between 0.01-0.03mm. The rotor magnet is made of high-performance permanent magnet NdFeB material and an adjustment slot is added to the end of the rotor shaft to adjust the magnetic field direction of the rotor magnet so that the magnetic field direction of the rotor magnet is consistent with the external strong magnetic field.

[0053] Specifically, the high-overload, high-strength permanent magnet DC motor is applied to the field of permanent magnet DC brushless slotless motors. When the device receives a start signal, the current in the stator assembly generates a rotating magnetic field through the winding. The device begins to detect the initial position of the rotor through the sensor assembly. The device interacts with the rotating magnetic field generated by the winding through the permanent magnet or induced current in the rotor assembly to generate torque, driving the rotor to start rotating. The device continuously detects the position of the rotor through the sensor assembly and converts the position information into an electrical signal. The current in the stator winding is adjusted according to the position information to keep the rotor rotating at the set speed and direction. During the operation of the motor, the stator assembly and the rotor assembly will generate a lot of heat. The structural design of the front cover assembly and the rear cover assembly helps to dissipate heat. The device also has a heat dissipation function through the stator assembly to ensure that the motor runs at an appropriate temperature. The front cover assembly, the rear cover assembly and the stator assembly together provide mechanical support for the motor. , to prevent damage to internal parts, the device has a buffering and shock-absorbing effect, reducing the vibration and noise when the motor is running. The device realizes efficient conversion between electrical energy and mechanical energy through precise magnetic field control and efficient heat dissipation design. It has high structural strength, good buffering and shock-absorbing effect, and precise sensor feedback mechanism to ensure the stability and reliability of motor operation. Efficient energy conversion and heat dissipation design reduce energy waste. The low noise and low vibration operating characteristics also meet environmental protection requirements. The modular design makes the various components of the motor easy to disassemble and replace. The prototype of the device has been subjected to an impact environment test with a value of 15000g. After the test, all indicators of the motor are normal, and in the ability to resist strong magnetic fields and radio frequency electromagnetic fields, the magnetic field strength is ≥4T, the magnetic field change rate is >1875T / s, and the magnetic field strength of the external radio frequency electromagnetic environment is 25V / m at a frequency of 10kHz-2MHz, and the magnetic field strength is 50V / m at a frequency of 2MHz-18GHz.

[0054] Specifically, deep groove ball bearings are provided in the front cover assembly and the rear cover assembly, and the design parameters of the deep groove ball bearings are set as follows: radial force Fr=15 (N), axial force Fa=2 (N), journal diameter d1=4 (mm), rotation speed n=9000 (r / min), required life Lh'=50000 (h), temperature coefficient ft=1, and lubrication method is grease lubrication. In the motor structure, the front cover and the stator housing, and the rear cover are all made of high-strength 316 material, and the material deformation is uniform on the way, and the front cover and the stator housing, and the rear cover and the stator housing are connected by laser welding to increase the strength.

[0055] In addition to the conventional deep groove ball bearings at both ends of the rotor, thrust ball bearings and disc spring structures are additionally added. Compared with the traditional structure, this structure can better withstand high overload impact; by controlling the axial clearance of the motor to between 0.01-0.03mm, the impact is reduced and the ability to resist high overload is improved.

[0056] The motor rotor magnet is made of high-performance permanent magnet NdFeB material, which has strong magnetic properties and is not easy to demagnetize;

[0057] An adjustment slot is added to the end of the rotor shaft to adjust the magnetic field direction of the rotor magnet so that the magnetic field direction of the rotor magnet is consistent with the external strong magnetic field, thereby achieving the purpose of resisting high-strength magnetism.

[0058] This high-overload, high-magnetic-strength permanent magnet DC motor has undergone a 15,000g shock environment test, and all indicators of the motor are normal after the test.

[0059] The motor housing, front and rear covers are made of 2Cr13 material, which has good corrosion resistance, atmospheric corrosion resistance and good heat treatment performance, and can meet different usage requirements. It has excellent high temperature strength and excellent work hardening performance. The strength and durability of this material are both excellent, and it also has good welding performance, which can better meet the usage requirements and processing and installation requirements. In order to ensure the internal structural strength of the motor, the winding and the stator core are sealed with epoxy glue at both ends to ensure the impact resistance and vibration resistance of the stator assembly; the internal rotor installation of the motor adopts a gap-eliminating structure design to effectively reduce the axial clearance of the motor and improve the motor's ability to resist high overload.

[0060] In terms of technology, the present invention controls the axial clearance of the whole machine to 0.01-0.03mm, reduces the axial displacement of the motor rotor under high overload, thereby reducing the impact on the bearings at both ends of the rotor, so that they will not be damaged under high overload conditions; the front and rear covers of the motor and the casing are laser welded with the same material, which greatly enhances the overload resistance of the whole machine.

[0061] Specifically, the radial force refers to the force perpendicular to the tangent direction of the circle passing through the point, the axial force refers to the force acting on the object and its direction is along the axial direction, the journal diameter refers to the maximum diameter of a specific area on the shaft, the rotational speed refers to the number of revolutions of the object around the center of the circle per unit time, the required life refers to the shortest service life expected to be achieved by the product, equipment and system under normal conditions of use to meet the predetermined functional and performance requirements, the temperature coefficient refers to the rate at which the physical properties of the material change with temperature, and grease lubrication refers to the use of grease or lipid substances applied to mechanical equipment as lubricants to reduce the friction of the mechanical equipment during movement.

[0062] See also Figure 2 As shown, it is a schematic structural diagram of the stator assembly of this embodiment, and the stator assembly includes:

[0063] The housing 02-1 is connected to the core 02-2 and is used to protect the internal components of the motor and provide mechanical support;

[0064] The iron core 02-2 is connected to the housing 02-1 and the insulating paper 02-4 and is used to enhance the magnetic field and control the direction of the magnetic field;

[0065] Winding 02-3, which is connected to insulating paper 02-4, is used for power transmission, voltage conversion and power regulation; the winding and both ends of the core are sealed with epoxy glue;

[0066] The insulating paper 02-4 is connected to the iron core 02-2 and the winding 02-3 and is used to increase the insulation distance between the winding 02-3 and the iron core 02-2.

[0067] Specifically, in the stator assembly, the core structure is set to a slotless structure, the material is 20WTG1500 electrical cold-rolled silicon steel sheet, and it is bonded to the casing with a two-component epoxy adhesive. The insulating paper material is a 6650 composite material with a thickness of 0.15 mm, and the winding material is a hot air self-adhesive wire with a temperature resistance grade of 180°C. The winding method is a diamond wire petal bonding method, and the winding and the two ends of the core are sealed with epoxy adhesive. The casing is made of stainless round steel 2Cr13. The casing uses high-strength 316 material, the material deformation is uniform, and laser welding is used.

[0068] Specifically, the slotless structure refers to the removal of the traditional tooth groove structure, the 20WTG1500 cold-rolled silicon steel sheet for electrical use refers to a ferrosilicon alloy containing 0.8%-4.8% silicon, which is a soft magnetic alloy material formed by cold rolling, the two-component epoxy adhesive refers to a thermosetting resin glue composed of an epoxy resin component and a hardener component, the 6650 composite material refers to a material composed of two layers of polyaramid fiber paper with a polyimide film sandwiched in between and compounded with an adhesive, the hot air self-adhesive wire with a temperature resistance grade of 180°C refers to a high-performance structural adhesive made of polyimide and other thermoplastic resins, the epoxy adhesive refers to an engineering adhesive prepared from an epoxy resin base material, a curing agent, a diluent, a accelerator and a filler, and the stainless round steel 2Cr13 refers to a stainless steel material with a martensitic structure.

[0069] Specifically, the winding is trial-wound on a semi-automatic winding machine using a winding plate and a wire pressing plate according to the requirements of the preset drawings, and the wound wire petals are measured according to the requirements of the preset drawings, and the parameter settings of the semi-automatic winding machine are adjusted until the formed wire petals meet the requirements of the preset drawings, and the wire petals are arranged in sequence on top using a clamp, and the joints of adjacent wire petals are bonded and fixed using a two-component epoxy glue, and then the positioning device is placed together with the wire petals on the winding bonding machine, the wire petals are continuously kept warm and pressurized, the wire petal taps are arranged and cut, and the cut wire petals are hot-pressed, and then the hot-pressed wire petals are placed on a winding machine, and the rolling mold on the rolling machine is used to perform the rolling operation to form a preliminary winding, and the preliminary winding is placed on a shaping machine for rough shaping and fine shaping in steps, a layer of single-component solid glue is evenly applied to the inner and outer surfaces of the shaped winding, and a pressure device is used to fix and press the winding, and the high temperature is maintained to form the final winding.

[0070] Specifically, the preset drawing refers to a pre-set drawing template, the semi-automatic winding machine refers to industrial production equipment used for wire winding and wire binding, the preset tooling refers to process equipment designed, manufactured and configured in advance for a specific production process, the wire petal refers to a single or a group of wire segments that make up the winding, the two-component epoxy adhesive refers to a common industrial adhesive, mainly composed of epoxy resin and curing agent, the rolling machine refers to a machine used for rolling metal objects, the shaping machine refers to a machine that can process materials into parts of different shapes and sizes, the rough shaping refers to the preliminary shape adjustment or processing of the original material or semi-finished product during the processing or manufacturing process, and the fine shaping refers to further improving the size accuracy, shape accuracy and surface roughness of the workpiece.

[0071] See also Figure 3 As shown, it is a schematic diagram of the structure of the rotor assembly of this embodiment, and the rotor assembly includes:

[0072] The rotating shaft 03-1 is connected with the magnetic steel 03-2, the front bearing retaining ring 03-3 and the rear bearing retaining ring 03-4, and is used to realize the relative rotational movement between the mechanical parts, transmit the torque and bear the bending moment;

[0073] The magnetic steel 03-2 is connected to the front bearing retaining ring 03-3 and the rear bearing retaining ring 03-4, and is used to generate a magnetic field, convert electrical energy into mechanical energy, and drive the rotating shaft 03-1 to rotate;

[0074] The front bearing retaining ring 03-3 is connected to the rotating shaft 03-1 and is used to prevent the magnetic steel 03-2 from moving on the rotating shaft 03-1. It is also used to remove weight when the rotor is dynamically balanced.

[0075] The rear bearing retaining ring 03-4 is connected to the rotating shaft 03-1 and is used to prevent the magnetic steel 03-2 from moving on the rotating shaft 03-1. It is also used to remove weight when the rotor is dynamically balanced.

[0076] The sensor magnet 03-5 is connected to the rear bearing retaining ring 03-4 and is used to detect the working parameters of the permanent magnet DC motor that can resist high overload and high magnetic strength.

[0077] Specifically, in the rotor assembly, the magnetic steel material is set to be N52UH sintered NdFeB magnetic steel, the length is 28mm, the front bearing retaining ring and the rear bearing retaining ring are made of stainless steel 316, and the shaft material is stainless steel 2Cr13, and the hardness after heat treatment is HRC32-36, which fully increases the strength of the shaft. Specifically, the N52UH sintered NdFeB magnetic steel refers to a magnet material with extremely strong magnetism and can maintain stable performance in a high temperature environment, the stainless steel 316 refers to a stainless steel material of the austenitic stainless steel series, and the stainless steel 2Cr13 refers to a stainless steel material with a martensitic structure.

[0078] In order to meet the requirements of resistance to strong magnetic fields and radio frequency, the present invention rationally designs the motor housing and end cover materials and their structures to effectively reduce the impact of external magnetic fields entering the motor. A 1-pole motor structure is used, and high-precision control technology is used to ensure that the direction of the motor's internal magnetic field is consistent with the direction of the external strong magnetic field, thereby avoiding demagnetization. The final motor has the following capabilities to resist strong magnetic fields and radio frequency electromagnetic fields:

[0079] a) Magnetic field strength: A0 is greater than or equal to 4T;

[0080] b) Magnetic field change rate: greater than 1875T / s;

[0081] c) External RF electromagnetic environment: magnetic field strength is 25V / m at frequencies of 10kHz to 2MHz; magnetic field strength is 50V / m at frequencies of 2MHz to 18GHz.

[0082] In addition, the motor housing and front and rear covers are made of 2Cr13 material, which has excellent magnetic conductivity. When a layer of magnetic isolation material or air is added between the housing and the stator core, the external strong magnetic field will preferentially pass through the housing, thereby effectively weakening the impact of the external magnetic field on the inside of the motor. In addition, the Hall position sensor magnet is installed in a multi-layer balance ring composed of alternating 2Cr13 material and non-magnetic material to form a secondary shield, thereby forming a closed magnetic field diversion structure, which can ensure that the motor sensor magnet will not be demagnetized due to the strong external magnetic field.

[0083] The housing and the end cover are welded together using a laser welding process to form a closed internal space of the motor. This closed structure can effectively shield the interference of external radio frequency electromagnetic fields, further reduce the impact of external radio frequency electromagnetic fields on the internal magnetic field of the motor, and improve the stability and reliability of the motor in complex electromagnetic environments.

[0084] See also Figure 4 As shown, it is a schematic diagram of the structure of the Hall plate assembly of this embodiment, and the Hall plate assembly includes:

[0085] The Hall plate 04-1 is connected to the Hall sensor 04-2 and the lead wire 04-4, and is used to detect the magnetic field by using the Hall effect and convert it into a measurable electrical signal and output it;

[0086] The Hall sensor 04-2 is connected to the wire loop 04-3 and the Hall plate 04-1 and is used to convert the change of the magnetic field into the change of the electrical signal;

[0087] The wire passing ring 04-3 is connected to the Hall sensor 04-2 and is used to connect the winding to the external control system through the wire passing ring, and to fix and support the rotor winding;

[0088] The lead wire 04 - 4 is connected to the Hall plate 04 - 1 and is used to transmit a control signal.

[0089] Specifically, the external control system refers to a system that accurately controls the motor through electrical and electronic means, and the control signal refers to an electrical signal used to control the operating state and parameters of the motor.

[0090] Specifically, the Hall sensor is installed on a circuit board, and the wire ring material is set to PEEK, a high-temperature resistant material with a temperature resistance grade of 250°C. The copper foil width in the Hall circuit is 0.3mm, the current density is 2.38A / mm2, the copper foil thickness in the circuit board is 6 ounces, the copper foil width of the winding circuit is 0.6mm, and the current density is 15.87A / mm2.

[0091] Specifically, the high-temperature resistant material PEEK with a temperature resistance grade of 250°C refers to polyetheretherketone special fibers and resin materials, the Hall circuit refers to a Hall digital circuit composed of a voltage stabilizer, a Hall plate, a differential amplifier, a Schmitt trigger and an output stage, the copper foil refers to a cathodic electrolytic material deposited on the base layer of the circuit board as a conductor, the current density refers to the current intensity on the electrode per unit area, the ounce refers to the unit of weight for measuring precious metals, and the motor control system refers to a system for precisely controlling the motor through electrical and electronic means.

[0092] Specifically, in the permanent magnet DC motor capable of resisting high overload and high magnetic strength, the working process includes:

[0093] Step S1, when the winding in the stator assembly is energized, a magnetic field is generated around the iron core;

[0094] Step S2, when the magnetic steel in the rotor assembly interacts with the magnetic field, an electromagnetic torque is generated, thereby driving the shaft to rotate;

[0095] Step S3: the sensor assembly detects the position of the rotor assembly and the magnetic field strength, and converts the position of the rotor assembly and the magnetic field strength into electrical signals.

[0096] The front cover, back cover and housing model were simulated to apply a 20000g radial impact. The simulation results are as follows: Figure 5 As shown in the figure, the maximum deformation of the housing and rear cover is 3.6um (0.0036mm), and the radial clearance of the bearing is 5-12.5um. The deformation here is within the radial clearance range of the bearing, and the bearing will not be damaged, which can ensure the normal operation of the motor under high overload conditions.

[0097] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A permanent magnet DC motor capable of resisting high overload and high magnetic strength, characterized in that: include: A front cover assembly, which is connected to the stator assembly and the rotor assembly and is used for buffering and shock absorption, heat dissipation and cooling, and magnetic shielding; The stator assembly is connected to the front cover assembly, the rotor assembly and the sensor assembly, and is used to provide a magnetic field, drive the rotor assembly to rotate, dissipate the heat generated by the generator, and provide mechanical support; A rotor assembly, which is connected to the front cover assembly, the stator assembly, the sensor assembly and the rear cover assembly, and is used to interact with the magnetic field generated by the winding, drive the motor to rotate, and withstand mechanical stress, control temperature and resist magnetic interference; A sensor assembly connected to the stator assembly and the rear cover assembly, for detecting the position and magnetic field of the rotor assembly and converting the position and magnetic field of the rotor assembly into electrical signals; A rear cover assembly, which is connected to the stator assembly and the rotor assembly, and is used to provide mechanical support for the motor and protect the internal components of the motor; Among them, the front cover and stator casing, as well as the rear cover and stator casing are connected by laser welding. In addition to the conventional deep groove ball bearings at both ends of the rotor, thrust ball bearings and disc spring structures are additionally added. The axial clearance of the motor is controlled to be between 0.01-0.03mm. The rotor magnet is made of high-performance permanent magnet NdFeB material and an adjustment slot is added to the end of the rotor shaft to adjust the magnetic field direction of the rotor magnet so that the magnetic field direction of the rotor magnet is consistent with the external strong magnetic field.

2. The high overload resistant, high magnetic strength permanent magnet DC motor according to claim 1, characterized in that: Deep groove ball bearings are provided in the front cover assembly and the rear cover assembly, and the design parameters of the deep groove ball bearings are set as follows: radial force Fr=15 (N), axial force Fa=2 (N), journal diameter d1=4 (mm), rotation speed n=9000 (r / min), required life Lh'=50000 (h), temperature coefficient ft=1, and lubrication method is grease lubrication.

3. The high overload resistant, high magnetic strength permanent magnet DC motor according to claim 1, characterized in that: The stator assembly comprises: The casing is connected to the core and is used to protect the internal components of the motor and provide mechanical support; The iron core is connected to the casing and the insulating paper and is used to enhance the magnetic field and control the direction of the magnetic field; The winding is connected to the insulating paper and is used for power transmission, voltage conversion and power regulation; the winding and the two ends of the iron core are sealed with epoxy glue; Insulating paper is connected to the iron core and the winding to increase the insulation distance between the winding and the iron core.

4. The high overload resistant, high magnetic strength permanent magnet DC motor according to claim 3, characterized in that: In the stator assembly, the core structure is set to a slotless structure, the material is 20WTG1500 electrical cold-rolled silicon steel sheet, and it is bonded to the casing with a two-component epoxy adhesive. The insulating paper material is a 6650 composite material with a thickness of 0.15 mm. The winding material is a hot air self-adhesive wire with a temperature resistance grade of 180°C. The winding method is a diamond wire petal bonding method. The winding and the two ends of the core are sealed with epoxy adhesive. The casing and the front and rear covers are made of stainless round steel 2Cr13.

5. The high overload resistant, high magnetic strength permanent magnet DC motor according to claim 3, characterized in that: The winding is trial-wound on a semi-automatic winding machine using a winding plate and a wire pressing plate according to the requirements of the preset drawings, and the wound wire petals are measured according to the requirements of the preset drawings, and the parameter settings of the semi-automatic winding machine are adjusted until the formed wire petals meet the requirements of the preset drawings, and the wire petals are arranged in sequence on top using a clamp, and two-component epoxy glue is used to bond and fix the joints of adjacent wire petals, and then the positioning device is placed together with the wire petals on the winding bonding machine, the wire petals are continuously kept warm and pressurized, the wire petal taps are arranged and cut, the cut wire petals are hot-pressed, and then the hot-pressed wire petals are placed on a winding machine, and the rolling mold on the rolling machine is used to perform a rolling operation to form a preliminary winding, and the preliminary winding is placed on a shaping machine for rough shaping and fine shaping in steps, a layer of single-component solid glue is evenly applied to the inner and outer surfaces of the shaped winding, and a pressure device is used to fix and press the winding, and the high temperature is maintained to form the final winding.

6. The high overload resistant, high magnetic strength permanent magnet DC motor according to claim 1, characterized in that: The rotor assembly comprises: A rotating shaft connected to the magnetic steel, the front bearing retaining ring and the rear bearing retaining ring for transmitting torque and bearing bending moment; A magnetic steel connected to the front bearing retaining ring and the rear bearing retaining ring, used to generate a magnetic field, convert electrical energy into mechanical energy, and drive the shaft to rotate; The front bearing retaining ring is connected to the rotating shaft and is used to prevent the magnetic steel from moving on the rotating shaft. It is also used to remove weight when the rotor is dynamically balanced. The rear bearing retaining ring is connected to the rotating shaft and is used to prevent the magnetic steel from moving on the rotating shaft. It is also used to remove weight when the rotor is dynamically balanced. The sensor magnet is connected to the rear bearing retaining ring and is used to detect the working parameters of the permanent magnet DC motor that resists high overload and high magnetic strength.

7. The high overload resistant, high magnetic strength permanent magnet DC motor according to claim 6, characterized in that: In the rotor assembly, the magnetic steel material is set to N52UH sintered NdFeB magnetic steel, the length is 28 mm, the front bearing retaining ring and the rear bearing retaining ring are made of stainless round steel 316, and the shaft material is stainless round steel 2Cr13.

8. The high overload resistant, high magnetic strength permanent magnet DC motor according to claim 1, characterized in that: The Hall plate assembly comprises: A Hall plate, which is connected to the Hall sensor and lead wires, and is used to detect the magnetic field using the Hall effect and convert it into a measurable electrical signal and output it; A Hall sensor is connected to the wire loop and the Hall plate and is used to convert changes in the magnetic field into changes in electrical signals; A wire passing ring, which is connected to a Hall sensor and is used to connect the winding to an external control system through the wire passing ring, and to fix and support the rotor winding; Lead wires are connected to the Hall plate and are used to transmit control signals.

9. The high overload resistant, high magnetic strength permanent magnet DC motor according to claim 8, characterized in that: The Hall sensor is installed on a circuit board, and the wire ring material is set to be PEEK, a high-temperature resistant material with a temperature resistance grade of 250°C. The copper foil width in the Hall circuit is 0.3mm, the current density is 2.38A / mm2, the copper foil thickness in the circuit board is 6 ounces, the copper foil width of the winding circuit is 0.6mm, and the current density is 15.87A / mm2.

10. The high overload resistant, high magnetic strength permanent magnet DC motor according to claim 1, characterized in that: In the permanent magnet DC motor capable of resisting high overload and high magnetic strength, the working process includes: Step S1, when the winding in the stator assembly is energized, a magnetic field is generated around the iron core; Step S2, when the magnetic steel in the rotor assembly interacts with the magnetic field, an electromagnetic torque is generated, thereby driving the shaft to rotate; Step S3: the sensor assembly detects the position of the rotor assembly and the magnetic field strength, and converts the position of the rotor assembly and the magnetic field strength into electrical signals.

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