Coreless motor

Abstract

According to the coreless motor provided by the invention, three groups of hollow coil groups are uniformly arranged on the inner circumferential wall of a driving cavity in a surrounding manner, the coils as stator parts do not contain iron cores, and the two ends of the coils are not communicated with each other, that is, each group of coils is electrically independent, so that a three-phase six-wire driving mode is realized. The full-bridge driving structures arranged in the driving cavity are connected to the two ends of each set of coils respectively, each full bridge controls one set of coils, and therefore the current direction and amplitude of each set of windings can be independently adjusted. When the motor is powered on, the hollow coil generates an alternating magnetic field under the action of current, and interacts with a rotatable magnetic driving piece located in the axis direction of the motor to form electromagnetic torque so as to drive the magnetic driving piece to rotate. The magnetic driving part is arranged around the axis and surrounded by the coil, and good magnetic flux coupling and stable rotation output are achieved. And in cooperation with a full-bridge driving structure, three-phase six-wire independent control is supported, the driving freedom degree is higher, the current waveform can be finely adjusted, and high-precision servo control is achieved.

Description

Technical Field

[0001] The present application relates to the field of motors, and in particular to a coreless motor. Background Art

[0002] In the fields of new energy vehicle drive and high-end robotic joint manufacturing, motors with high torque, high speed, and precise control are often required to meet the requirements of greater output power, higher control accuracy, and finer current control precision. In these cases, three-phase, six-wire motors are required for driving. Unlike traditional three-phase motors, three-phase, six-wire motors have two terminals for each winding set connected separately. The windings are not connected in a fixed star or delta configuration. Instead, the driver independently controls each winding set through three full-bridge circuits, achieving greater output power, greater control flexibility, and more precise current modulation accuracy.

[0003] However, this structure is currently rarely used in coreless motors. Traditional coreless motors use an ironless hollow coil as the rotor and a permanent magnet as the stator. Because the armature lacks an iron core, energy loss due to hysteresis and eddy currents, known as iron losses, is avoided. Furthermore, the lightweight rotor structure results in an extremely low moment of inertia, enabling excellent dynamic response and low energy consumption. This makes them widely used in applications requiring high response speed, such as aerospace equipment and precision servo actuators.

[0004] However, coreless motors also have significant limitations: Because the rotor lacks an iron core for support, its mass and moment of inertia are small, limiting its torque output. Meanwhile, while three-phase, six-wire drives offer the advantage of high power output, they also draw high coil currents, which can lead to severe heating. Conventional motors also suffer from significant iron losses.

[0005] In view of this, if three-phase six-wire drive technology can be combined with hollow cup motors and the rotor inertia can be increased while maintaining zero iron loss, it will be possible to simultaneously take into account high torque output, fast response and efficient control, thereby significantly expanding the application boundaries of motors in high-performance fields. Summary of the Invention

[0006] In view of this, it is necessary to provide a coreless motor to solve the above problems.

[0007] An embodiment of the present application provides a coreless motor, comprising:

[0008] a housing having a driving cavity formed therein;

[0009] The hollow coil groups are arranged around the inner peripheral wall of the driving cavity, and the two ends of the three hollow coil groups are not connected to each other;

[0010] A full-bridge drive structure is provided in the drive cavity and is electrically connected to both ends of the three groups of hollow coils respectively;

[0011] The magnetic driving member is arranged in the movement cavity along the axial direction of the driving cavity and is rotatably connected to the shell. The hollow coil group is arranged around the magnetic driving member.

[0012] In at least one embodiment of the present application, the hollow coil group includes: a first coil group, a second coil group and a third coil group, and the first coil group, the second coil group and the third coil group are arranged at equal angles on the inner wall of the driving cavity.

[0013] In at least one embodiment of the present application, the full-bridge drive structure includes:

[0014] a first driver electrically connected to both ends of the first coil group;

[0015] a second driver electrically connected to both ends of the second coil group;

[0016] The third driver is electrically connected to both ends of the third coil group.

[0017] In at least one embodiment of the present application, the coreless motor further comprises:

[0018] The wire group has three groups of electrical connection lines, each group of the electrical connection lines includes two, and the first driver, the second driver and the third driver are electrically connected to a group of the electrical connection lines respectively.

[0019] In at least one embodiment of the present application, the coreless motor further comprises:

[0020] A rotating shaft is provided through the magnetic driving member and is rotatably connected to the housing.

[0021] In at least one embodiment of the present application, the coreless motor further comprises:

[0022] a first bearing, disposed at one end of the housing;

[0023] The second bearing is provided at the other end of the housing. The first bearing and the second bearing are fixedly connected to the rotating shaft respectively. One end of the rotating shaft passes through the housing and extends to the outside.

[0024] In at least one embodiment of the present application, the coreless motor further comprises:

[0025] a shaft sleeve, sleeved on one end of the rotating shaft and located between the first bearing and the magnetic driving member;

[0026] The circuit board is sleeved outside the shaft sleeve and is electrically connected to the full-bridge drive structure.

[0027] In at least one embodiment of the present application, the coreless motor further comprises:

[0028] A spring is installed between the second bearing and the magnetic driving component, and two ends of the spring are respectively in contact with the second bearing and the magnetic driving component.

[0029] In at least one embodiment of the present application, there is a gap between the air-core coil group and the magnetic driving member.

[0030] In at least one embodiment of the present application, the magnetic driving member is a two-pole magnet.

[0031] In at least one embodiment of the present application, the magnetic driving member is a multi-polar magnet.

[0032] The coreless motor of this embodiment has at least the following beneficial effects:

[0033] The hollow cup motor provided above has three groups of hollow coils evenly arranged around the inner wall of the drive cavity. These coils do not contain an iron core as the stator part, and their two ends are not connected to each other, that is, each group of coils is electrically independent, realizing a three-phase six-wire drive mode.

[0034] The full-bridge drive structure within the drive cavity is connected to the two ends of each set of coils. Each full-bridge controls one set of coils, enabling independent adjustment of the current direction and amplitude of each winding. When the three sets of coils are energized sequentially, the air-core coils generate an alternating magnetic field under the action of the current. This interacts with the rotatable magnetic drive element (rotor) located along the motor axis, generating electromagnetic torque, which in turn drives its rotation. The magnetic drive element is arranged around the axis and surrounded by the coils, achieving good magnetic flux coupling and stable rotational output.

[0035] The ends of the three sets of coils are not connected to each other. Combined with the full-bridge drive structure, it supports three-phase six-wire independent control. Compared with the traditional connection method, it has higher driving freedom, can finely adjust the current waveform, and achieve high-precision servo control. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is the structural diagram of the coreless motor;

[0037] Figure 2 This is the exploded view of the coreless motor;

[0038] Figure 3 This is a cross-sectional view of a coreless motor;

[0039] Figure 4 This is a partial structural diagram of the coreless motor;

[0040] Figure 5 It is a connection diagram of the hollow coil group and the full-bridge drive structure.

[0041] Description of main component symbols

[0042] 100. Coreless motor;

[0043] 110, housing; 110a, driving chamber;

[0044] 120, air-core coil group; 121, first coil group; 122, second coil group; 123, third coil group;

[0045] 130. Full-bridge drive structure; 131. First driver; 132. Second driver; 133. Third driver;

[0046] 140. Magnetic drive components;

[0047] 150, conductor wire assembly;

[0048] 160, rotating shaft;

[0049] 170. First bearing; 171. Second bearing; 172. Bushing; 173. Circuit board; 174. Spring. DETAILED DESCRIPTION

[0050] The embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0051] It should be noted that when a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intermediate component. When a component is considered to be "disposed on" another component, it can be directly disposed on the other component or there may be an intermediate component. The terms "top", "bottom", "upper", "lower", "left", "right", "front", "back", and similar expressions used herein are for illustrative purposes only.

[0052] The following embodiments of the present application are described in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features therein may be combined with each other.

[0053] An embodiment of the present application provides a coreless motor 100, comprising:

[0054] The housing 110 has a driving cavity 110a formed therein;

[0055] The hollow coil groups 120 are arranged around the inner wall of the driving cavity 110a, and the two ends of the three hollow coil groups 120 are not connected to each other;

[0056] The full-bridge drive structure 130 is disposed in the drive cavity 110a and is electrically connected to both ends of the three hollow coil groups 120 respectively;

[0057] The magnetic driving member 140 is disposed in the motion cavity along the axial direction of the driving cavity 110 a and is rotatably connected to the housing 110 . The hollow coil assembly 120 is disposed around the magnetic driving member 140 .

[0058] Please refer to Figure 1-Figure 5 In this embodiment, the housing 110 defines a closed drive chamber 110a, which houses the motor's main functional components. Three sets of hollow coils 120 are evenly arranged around the inner wall of the drive chamber 110a. These coils, serving as the stator, lack an iron core and are disconnected from each other. This means each set of coils is electrically independent, enabling a three-phase, six-wire drive system.

[0059] The full-bridge drive structure 130, located within the drive cavity 110a, is connected to the two ends of each set of coils. Each full-bridge controls a set of coils, enabling the current direction and amplitude of each winding to be independently adjusted. When the three sets of coils are energized sequentially, the air-core coils generate an alternating magnetic field under the action of the current. This interacts with the rotatable magnetic drive element 140 (rotor) located in the direction of the motor axis, forming an electromagnetic torque, thereby driving its rotation. The magnetic drive element 140 is arranged around the axis and surrounded by the coils, achieving good magnetic flux coupling and stable rotational output.

[0060] The ends of the three sets of coils are not connected to each other. Combined with the full-bridge drive structure 130, it supports three-phase six-wire independent control. Compared with the traditional connection method, it has higher driving freedom, can finely adjust the current waveform, and achieve high-precision servo control.

[0061] The full-bridge drive can provide greater current excitation, and combined with electrically independent windings, it helps to increase the magnetic flux density and electromagnetic torque output per unit volume, thereby compensating for the problem of insufficient torque of the traditional hollow cup motor 100.

[0062] The hollow coil structure avoids the hysteresis loss and eddy current loss caused by the iron core. At the same time, the surround arrangement reduces the moment of inertia, giving the motor dynamic characteristics of fast response and high energy efficiency.

[0063] It should be noted that the housing 110 is generally cylindrical, with both ends open and a cavity in the middle, namely, the driving cavity 110a. The hollow coil assembly 120 is a hollow magnetic induction coil. The magnetic driving member 140 is a magnet.

[0064] In at least one embodiment of the present application, the hollow coil group 120 includes: a first coil group 121, a second coil group 122 and a third coil group 123, and the first coil group 121, the second coil group 122 and the third coil group 123 are arranged at equal angles on the inner wall of the driving cavity 110a.

[0065] Please refer to Figure 1-Figure 5 In this embodiment, the hollow coil assembly 120 is composed of three independent coil groups: a first coil group 121, a second coil group 122, and a third coil group 123. These three coil groups are installed at equal angles on the inner circumference of the drive cavity 110a, forming the three-phase winding system of the motor.

[0066] The three groups of coils are evenly distributed at an electrical angle of 120 degrees in the circumferential direction, which is conducive to forming a symmetrical and balanced rotating magnetic field when the motor is running.

[0067] Because the hollow coils lack an iron core, their magnetic field changes after excitation respond extremely quickly, maintaining a high degree of synchronization with changes in the drive current. When three-phase current is applied sequentially to three equally spaced coils according to a specific pattern, these hollow coils form a continuously rotating magnetic field in a circumferential direction between the coil interior and the magnetic drive element 140. This rotating magnetic field interacts with the central magnetic drive element 140 (rotor), generating a stable electromagnetic torque that drives the rotor.

[0068] Since this structure adopts three-phase six-wire drive, both ends of each coil are controlled by independent drivers, so high-precision modulation of each phase current can be achieved, thereby improving the control capability and operating efficiency of the whole machine.

[0069] The equal-angle distribution of the three sets of coils can ensure the formation of a spatially symmetrical rotating magnetic field when powered. The symmetrical magnetic field can effectively reduce electromagnetic fluctuations, reduce mechanical vibration and noise, and improve the stability and reliability of motor operation.

[0070] The equiangular arrangement helps improve the coverage and consistency of the coil magnetic field in space, and improves the efficiency of the magnetic flux connection with the magnetic driver 140. This efficient coupling directly increases the electromagnetic torque output, which helps solve the problem of insufficient torque in traditional hollow cup motors 100.

[0071] Based on the symmetrical winding arrangement and combined with the full-bridge independent drive structure, each set of coils can perform independent current control, thereby achieving more detailed waveform modulation and magnetic field control, which is suitable for complex working conditions such as high-precision servo and variable speed start-stop.

[0072] On the basis of adopting an iron-coreless coil structure, the three-phase windings are arranged symmetrically, which can improve the motor performance while maintaining the inherent advantages of the hollow cup motor 100 such as low inertia, high response, and high efficiency.

[0073] In at least one embodiment of the present application, the full-bridge drive structure 130 includes:

[0074] A first driver 131 is electrically connected to both ends of the first coil assembly 121;

[0075] a second driver 132 electrically connected to both ends of the second coil assembly 122;

[0076] The third driver 133 is electrically connected to both ends of the third coil assembly 123 .

[0077] Please refer to Figure 1-Figure 5 In this embodiment, the air-core coil assembly 120 consists of three independent windings: a first coil assembly 121, a second coil assembly 122, and a third coil assembly 123. The two ends of each coil assembly are independently connected, forming a three-phase, six-wire winding topology. To achieve precise drive control of these three coils, this embodiment introduces three independent full-bridge drivers: a first driver 131, a second driver 132, and a third driver 133. Each driver is electrically connected to two terminals of a coil assembly.

[0078] The so-called full-bridge driver refers to a bridge drive circuit composed of four power switches (such as MOSFETs or IGBTs), which can realize forward and reverse power supply at both ends of a group of coils. That is, by controlling the conduction state of the upper and lower bridge arms, the bidirectional flow of current is realized, thereby driving the coil to generate a controllable magnetic field.

[0079] In actual operation, the control system independently adjusts the switching states of the three full-bridge drivers, injecting sequential current into each coil according to the three-phase waveform output pattern. Because each driver group and its corresponding coil group are independently controlled, the system can dynamically adjust the amplitude and phase of each phase current using a variety of control strategies, such as sinusoidal, trapezoidal, and space vector PWM (SVPWM), achieving high-precision and highly dynamic rotating magnetic field control.

[0080] This driving mode is completely different from the centralized control method used in traditional star or triangle winding structures, and has higher flexibility and control accuracy.

[0081] Each coil group is independently connected to a full-bridge driver, achieving decoupled control of the three-phase windings. This allows the control system to dynamically distribute current based on real-time parameters such as load status, motor temperature rise, and operating mode, achieving more flexible control.

[0082] The three sets of drivers control their respective coils and can independently adjust the current waveform, frequency and phase, thereby achieving more precise magnetic field control and smoother torque output. They are particularly suitable for high-precision servo systems and applications with extremely high dynamic response requirements.

[0083] In scenarios requiring high power and high control flexibility, such as new energy vehicles and robot joints, the three-phase six-wire combined with three full-bridge drivers can effectively improve the current supply capacity and system thermal balance, while ensuring motor performance and reducing the risk of coil heating concentration, thereby increasing the system's stable operation time.

[0084] The coreless motor 100 utilizes a coreless winding structure, resulting in minimal losses. Precise modulation achieved through three full-bridge drivers further reduces energy waste and improves overall drive system efficiency and control, making it particularly suitable for applications requiring stringent energy efficiency and control responsiveness.

[0085] In at least one embodiment of the present application, the coreless motor 100 further includes:

[0086] The wire group 150 has three groups of electrical connection lines, each group of the electrical connection lines includes two, and the first driver 131, the second driver 132 and the third driver 133 are electrically connected to a group of the electrical connection lines respectively.

[0087] Please refer to Figure 1-Figure 5 In this embodiment, the wire assembly 150 includes three sets of electrical connections, each consisting of two wires, correspondingly connecting the two output terminals of a driver. Therefore, the first, second, and third drivers 133 are each electrically connected to the corresponding set of wires in the wire assembly 150 via independent two-wire connections.

[0088] Each set of electrical connections independently connects to two terminals of a driver, achieving a one-to-one, physically isolated electrical connection. This effectively prevents signal crosstalk between different phases, ensuring that each phase coil can be completely independently controlled, providing the foundation for high-precision three-phase, six-wire drive.

[0089] Each set of electrical connection wires transmits only the current signal of one set of drivers, and is transmitted in pairs. This makes it suitable for differential design or shielded cables, which helps improve resistance to electromagnetic interference and ensure stable transmission of control signals under complex working conditions. It is particularly suitable for high-frequency, high-speed, and high-precision drive applications.

[0090] In at least one embodiment of the present application, the coreless motor 100 further includes:

[0091] The rotating shaft 160 is disposed through the magnetic driving component 140 and is rotatably connected to the housing 110 .

[0092] Please refer to Figure 1-Figure 5 In this embodiment, the rotating shaft 160 is disposed within the magnetic driver 140, axially extending throughout the entire magnetic driver 140 and forming a structural unit integrally connected to the magnetic driver 140. The other end of the rotating shaft 160 is rotationally connected to the housing 110 via a bearing or other mechanism, structurally providing support and guidance for the motor output.

[0093] When the hollow coil assembly 120 is activated by a three-phase, six-wire independent driver, a rotating magnetic field is formed between the stator and the magnetic driver 140, thereby driving the magnetic driver 140 to rotate. Since the rotating shaft 160 runs through it, the rotational motion is also transmitted to the rotating shaft 160. The rotating shaft 160 relies on a rotational connection with the housing 110 (for example, through front and rear bearings) to achieve stable operation and output the rotational kinetic energy converted from electromagnetic energy to an external mechanical system, such as a robot joint, an aircraft servo, or a drive device for a new energy vehicle.

[0094] The rotating shaft 160 is rotatably connected to the shell 110 to form a complete driving structure. Especially when combined with the bearing structure, it can effectively limit the radial runout and axial movement of the rotor during operation, thereby ensuring that the magnetic drive component 140 maintains stable rotation in the magnetic field formed by the hollow coil, which helps to improve the magnetic field coupling efficiency and the overall life of the motor.

[0095] The rotating shaft 160 serves as a heat dissipation path, dissipating some of the heat generated by the magnetic drive 140 to the housing 110 or the connecting mechanism, thereby assisting in overall thermal management. Furthermore, its through-hole design facilitates the integration of control and transmission components such as encoders and couplings onto the shaft, improving system integration.

[0096] It should be noted that the rotating shaft 160 is roughly in the shape of a circular shaft and is made of high-strength stainless steel, alloy steel, titanium alloy, hard aluminum alloy or other materials.

[0097] In at least one embodiment of the present application, the coreless motor 100 further includes:

[0098] A first bearing 170 is provided at one end of the housing 110;

[0099] The second bearing 171 is provided at the other end of the housing 110 . The first bearing 170 and the second bearing 171 are fixedly connected to the rotating shaft 160 , respectively. One end of the rotating shaft 160 passes through the housing 110 and extends to the outside.

[0100] Please refer to Figure 1-Figure 5In this embodiment, the rotating shaft 160 serves as the output shaft of the magnetic drive element 140 (rotor). Its stable rotation and efficient output depend on a precise mechanical support structure. To this end, this embodiment provides a first bearing 170 and a second bearing 171 at each end of the housing 110. These two sets of bearings are fixedly connected to the rotating shaft 160 and together form the connection structure of the motor rotor.

[0101] A first bearing 170 is mounted on one end of the housing 110, and a second bearing 171 is mounted on the opposite end. These two bearings provide dual-end support for the rotating shaft 160. This ensures axial positioning and radial stability of the rotating shaft 160 during motor operation, preventing axial movement and radial runout during rotation. Furthermore, one end of the rotating shaft 160 extends through the housing 110 and outside the motor, transmitting the electromagnetically driven rotational motion to an external load, thereby achieving the motor's power transmission function.

[0102] During operation, when the hollow coil is energized to form a rotating magnetic field, magnetic drive element 140 rotates accordingly, driving the rotating shaft 160, which passes through it, to rotate synchronously. First and second bearings 171 provide low-friction, high-precision rotational guidance, thereby ensuring smooth operation and continuous output of rotating shaft 160.

[0103] The first bearing 170 and the second bearing 171 are symmetrically arranged at both ends of the housing 110, forming a typical dual-bearing support mode, which can effectively improve the support rigidity of the rotating shaft 160, reduce radial runout and mechanical noise, and improve the stability and service life of the motor.

[0104] The two-end support structure can suppress the shaft end swing caused by load changes or inertial impact, thereby maintaining the magnetic gap between the magnetic driver 140 and the hollow coil stable, avoiding electromagnetic efficiency fluctuations, and helping to achieve more consistent output and more precise current control.

[0105] In at least one embodiment of the present application, the coreless motor 100 further includes:

[0106] a shaft sleeve 172 , sleeved on one end of the rotating shaft 160 and located between the first bearing 170 and the magnetic driving member 140 ;

[0107] The circuit board 173 is sleeved on the shaft sleeve 172 and electrically connected to the full-bridge drive structure 130 .

[0108] Please refer to Figure 1-Figure 5 In this embodiment, a sleeve 172 is provided on the side of the motor close to the output end (i.e., between the first bearing 170 and the magnetic driving member 140). The sleeve 172 is fixed to one end of the rotating shaft 160 in the form of a sleeve, forming a structure that is easy to install.

[0109] A circuit board 173 is disposed around the outside of the sleeve 172 and is electrically connected to the full-bridge drive structure 130 within the coreless motor 100. This allows the circuit board 173 to be close to the drive signal output source without affecting the normal movement of the rotating components, thereby achieving a compact and coordinated layout of the electrical and mechanical components.

[0110] Circuit board 173, acting as a carrier for control signals or power distribution, connects to full-bridge drive structure 130 to provide control instructions or power to the three driver groups within the motor. Because circuit board 173 is mounted outside sleeve 172, which itself is fixed to shaft 160 but does not rotate, circuit board 173 remains stationary, ensuring stable operation and easy maintenance.

[0111] At the same time, the circuit board 173 is arranged in the axial middle area, that is, close to the periphery of the motor's core working components (such as the hollow coil group 120 and the magnetic drive component 140), which helps to shorten the electrical connection path, reduce transmission loss, and improve the system response speed and electrical integrity.

[0112] The bushing 172 serves as an intermediary structure between the circuit board 173 and the rotating shaft 160. It not only provides a mounting surface for the circuit board 173, but also prevents the circuit board 173 from directly contacting or interfering with the rotation of the rotating shaft 160, effectively isolating the dynamic conflict between the electrical structure and the mechanical transmission structure, and improving system reliability.

[0113] The circuit board 173 is positioned close to the drive structure, shortening the connection path, resulting in faster signal transmission and lower energy loss. It is also positioned away from the direct rotation area of ​​high-speed magnetic components, reducing the potential impact of electromagnetic disturbances and helping to improve signal quality and control accuracy.

[0114] In at least one embodiment of the present application, the coreless motor 100 further includes:

[0115] The spring 174 is installed between the second bearing 171 and the magnetic driving member 140 , and two ends of the spring 174 abut against the second bearing 171 and the magnetic driving member 140 respectively.

[0116] Please refer to Figure 1-Figure 5 In this embodiment, a spring 174 is provided at one end of the magnetic driving member 140, i.e., near the second bearing 171, with its two ends respectively abutting between the second bearing 171 and the magnetic driving member 140, forming a support structure with axial elastic preload.

[0117] The spring 174 is not set to generate rotational torque, but to introduce an axial elastic force in the motor structure to slightly press the magnetic drive component 140 in a specific direction (usually close to the first bearing 170 or the center of the coil) to achieve the purpose of axial position positioning or fine-tuning.

[0118] During operation, spring 174 maintains one end pressed against second bearing 171 and the other end acting on magnetic driver 140 without interfering with the rotation of magnetic driver 140. The spring's elastic recovery properties provide a continuous and flexible restoring force when the magnetic driver 140 undergoes axial micro-displacement due to factors such as manufacturing tolerances, thermal expansion and contraction, or external impact, effectively preventing displacement or misalignment with the coil and ensuring a stable electromagnetic gap.

[0119] The preload force generated by the spring 174 between the second bearing 171 and the magnetic drive component 140 can effectively prevent the magnetic drive component 140 from axial displacement caused by inertial fluctuations or external disturbances during operation, ensuring that it is always in the center of the magnetic flux path, thereby improving rotational stability and electromagnetic efficiency.

[0120] Coreless motor 100, due to its low moment of inertia and fast response, is susceptible to shock during high-speed starts and stops. The cushioning effect of spring 174 absorbs some of the shock load, reducing mechanical impact on bearings and connecting components and extending system life.

[0121] Motors are susceptible to thermal expansion and contraction during long-term operation or under high power density, particularly in the axial direction. Spring 174 provides a certain amount of axial floating space, which automatically compensates for structural dimensional changes caused by thermal fluctuations and prevents stress concentration or seizure.

[0122] In at least one embodiment of the present application, there is a gap between the air-core coil assembly 120 and the magnetic driving component 140 .

[0123] Please refer to Figure 1-Figure 5 In this embodiment, the hollow coil group 120 is fixed to the inner wall of the housing 110, and the magnetic driving member 140 (rotor) is located at the center and can rotate at high speed.

[0124] A uniform air gap is deliberately retained between the two to avoid mechanical contact and form the magnetic circuit space necessary for electromagnetic coupling.

[0125] When a three-phase six-wire full-bridge driver injects a pulse or sinusoidal current into the coil, the coil generates a rotating magnetic field; the magnetic field must cross the air gap and close with the rotor poles, generating an electromagnetic torque that cuts the magnetic lines of force, thereby driving the rotor to rotate.

[0126] The coreless motor has an extremely low rotor inertia and can be accelerated or decelerated frequently. The air gap provides sufficient radial safety distance to ensure that the rotor and stator will not rub or collide even at high speeds or transient shocks.

[0127] Air-core coils draw high currents and tend to heat up, while the rotor itself is affected by hysteresis and windage. The air gap allows the two to expand and contract independently during thermal expansion and contraction, preventing jamming and noise.

[0128] The gap can also absorb processing and assembly tolerances, simplify the manufacturing process, and improve batch consistency.

[0129] The air gap forms a natural convection channel, which helps to remove heat from the coil and rotor; at the same time, it avoids contact noise.

[0130] The air gap reduces the peripheral resistance of the rotor, allowing the coreless motor to maintain ultra-fast response and low energy consumption in high-speed and frequent start-stop scenarios.

[0131] In at least one embodiment of the present application, the magnetic driving member 140 is a two-pole magnet.

[0132] Please refer to Figure 1-Figure 5 In this embodiment, the magnetic driving member 140 is a two-pole magnet structure, that is, two magnetic pole regions are provided in the axial or radial direction thereof to form a magnetic field structure in which the N pole and the S pole are relatively distributed.

[0133] The two-pole magnets can be two axially arranged permanent magnets, or a single permanent magnet magnetized to form two polar regions at each end. During motor operation, the three-phase alternating current generated by the hollow coil forms a rotating magnetic field in space. This rotating magnetic field interacts with the two-pole magnetic field of the magnetic drive element 140, thereby generating a stable and continuous electromagnetic torque within the motor.

[0134] Due to the use of a two-pole magnet structure, the hollow coil will undergo a complete magnetic pole alternation during one rotation of the rotor, so that the magnetic field and current form a good electrical angle match, meeting the periodic change requirements of the three-phase drive waveform, thereby achieving efficient conversion of electrical energy to mechanical energy.

[0135] The two-pole magnet provides a stable symmetrical magnetic field distribution between the N-pole and S-pole. When interacting with the rotating magnetic field formed by the three-phase air-core coil, it can achieve good magnetic field synchronization and obtain continuous and stable electromagnetic torque output. It is an ideal matching structure for the three-phase six-wire drive system.

[0136] The two-pole magnet can provide a stable and regularly changing magnetic flux density during the rotation process, which is conducive to the precise sampling of the air-core coil and the closed-loop control of the driver, thereby improving the execution accuracy of the control algorithm.

[0137] The small number of magnetic poles makes the magnetic field switching frequency moderate, which helps the control system better track the motor status, avoids frequent commutation and electromagnetic noise caused by too many pole pairs, and improves the system operation stability and reliability.

[0138] In at least one embodiment of the present application, the magnetic driving member 140 is a multi-level magnet.

[0139] Please refer to Figure 1-Figure 5 In this embodiment, the magnetic driving member 140 is a multi-polar magnet, that is, a plurality of magnetic pole pairs are arranged in the circumferential direction (or axial direction) of the magnetic driving member 140 to form alternating N poles and S poles, so that it has multiple polar regions within a complete circle. During the rotation of the magnetic driving member 140, the hollow coil is induced to a higher frequency and more finely varied magnetic field distribution.

[0140] In conjunction with the three-phase six-wire drive structure, the air-core coil group 120 is continuously coupled with the multi-pole magnetic field of the multi-pole magnet under the control of the rotating magnetic field, thereby forming a denser and more continuous electromagnetic torque output.

[0141] The multi-pole magnet causes the air-core coil to undergo multiple magnetic pole changes when the motor runs one circle, which is equivalent to increasing the electrical angle density of the motor, thereby improving the waveform smoothness of the output torque and the motor response resolution.

[0142] The multi-stage magnet structure can provide more magnetic field change cycles within a unit rotation angle, allowing the air-core coil to generate continuous and uniform induced current, thereby significantly reducing torque fluctuations and commutation dead zone phenomena, and improving the smoothness of motor operation.

[0143] The multi-pole structure improves the sampling frequency of the magnetic signal, helping the drive control system to more accurately sense the changes in rotor position, thereby achieving more delicate closed-loop control (such as FOC or SVPWM algorithms), which is particularly suitable for high-response, high-precision servo control systems.

[0144] The multi-pole magnet forms a high magnetic flux density distribution per unit circumferential length, which enhances the magnetic coupling efficiency between the magnetic drive component 140 and the hollow coil, enabling the hollow cup motor 100 to achieve higher output power and energy efficiency ratio in a smaller volume.

[0145] The above is only an implementation method of the present application. It should be pointed out that for ordinary technicians in this field, improvements can be made without departing from the creative concept of the present application, but these all fall within the scope of protection of the present application.

Claims

1. A coreless motor, characterized in that: include: a housing having a driving cavity formed therein; The hollow coil groups are arranged around the inner peripheral wall of the driving cavity, and the two ends of the three hollow coil groups are not connected to each other; A full-bridge drive structure is provided in the drive cavity and is electrically connected to both ends of the three groups of hollow coils respectively; The magnetic driving member is arranged in the movement cavity along the axial direction of the driving cavity and is rotatably connected to the shell. The hollow coil group is arranged around the magnetic driving member.

2. The coreless motor according to claim 1, characterized in that: The hollow coil group includes: a first coil group, a second coil group and a third coil group, and the first coil group, the second coil group and the third coil group are arranged at equal angles on the inner peripheral wall of the driving cavity.

3. The coreless motor according to claim 2, characterized in that: The full-bridge drive structure includes: a first driver electrically connected to both ends of the first coil group; a second driver electrically connected to both ends of the second coil group; The third driver is electrically connected to both ends of the third coil group.

4. The coreless motor according to claim 3, characterized in that: The coreless motor further comprises: The wire group has three groups of electrical connection lines, each group of the electrical connection lines includes two, and the first driver, the second driver and the third driver are electrically connected to a group of the electrical connection lines respectively.

5. The coreless motor according to claim 1, characterized in that: The coreless motor further comprises: A rotating shaft is provided through the magnetic driving member and is rotatably connected to the housing.

6. The coreless motor according to claim 5, characterized in that: The coreless motor further comprises: a first bearing, disposed at one end of the housing; The second bearing is provided at the other end of the housing. The first bearing and the second bearing are fixedly connected to the rotating shaft respectively. One end of the rotating shaft passes through the housing and extends to the outside.

7. The coreless motor according to claim 6, characterized in that: The coreless motor further comprises: a shaft sleeve, sleeved on one end of the rotating shaft and located between the first bearing and the magnetic driving member; The circuit board is sleeved outside the shaft sleeve and is electrically connected to the full-bridge drive structure.

8. The coreless motor according to claim 7, characterized in that: The coreless motor further comprises: A spring is installed between the second bearing and the magnetic driving component, and two ends of the spring are respectively in contact with the second bearing and the magnetic driving component.

9. The coreless motor according to claim 1, characterized in that: There is a gap between the air-core coil group and the magnetic driving component.

10. The coreless motor according to claim 1, characterized in that: The magnetic driving member is a two-stage magnet or a multi-stage magnet.

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