A brushless DC motor

Abstract

The present application discloses a brushless DC motor, which includes a rotor assembly. The rotor assembly includes a rotatable shaft, a rotor magnetic pole sleeved on the outer periphery of the shaft, and a magnetic ring assembly disposed at the end of the shaft. The magnetic ring assembly is threadedly connected to the shaft. By applying the brushless DC motor provided by the present application, the magnetic ring assembly can be rotated through a threaded structure to adjust the radial deflection angle between the magnetic ring assembly and the rotor magnetic pole, change the commutation deflection angle of the motor Hall potential relative to the armature back electromotive force, and achieve the effect of adjustable motor performance.

Description

Technical Field

[0001] The present application relates to the technical field of motors, and more specifically, to a brushless DC motor. Background Art

[0002] At present, a rotor magnetic pole and a Hall magnetic ring are provided on the rotor of a brushless DC motor. After assembly, the rotor magnetic pole and the Hall magnetic ring remain relatively fixed, and their installation positions cannot be adjusted, so that performance parameters such as the torque and current of the motor cannot be flexibly adjusted according to user requirements.

[0003] Therefore, how to provide a solution to the above technical problems is an issue that those skilled in the art need to solve currently. Summary of the Invention

[0004] In view of this, the purpose of the present application is to provide a brushless DC motor, in which the commutation angle of the motor Hall electromotive force relative to the armature back electromotive force can be flexibly adjusted according to requirements, meeting the different performance requirements of users.

[0005] To achieve the above purpose, the present application provides the following technical solutions:

[0006] A brushless DC motor includes a rotor assembly, the rotor assembly includes a rotatable shaft, a rotor magnetic pole sleeved on the outer periphery of the shaft, and a magnetic ring assembly provided at the end of the shaft, and the magnetic ring assembly is threadedly connected to the shaft.

[0007] Optionally, the brushless DC motor further includes a stator assembly sleeved on the outer periphery of the rotor assembly, and the stator assembly includes an insulating sheath, a stator core provided with auxiliary grooves, and a three-phase winding wound on the stator core.

[0008] Optionally, the brushless DC motor further includes a front end cover and a rear end cover respectively provided at the front end and the rear end of the stator assembly, the front end and the rear end of the shaft are pivotally mounted on the front end cover and the rear end cover through a front end bearing and a rear end bearing respectively, and a wave washer abutting against the end face of the front end bearing is provided in the bearing chamber of the front end cover.

[0009] Optionally, the magnetic ring assembly includes a magnetic ring sleeve and a Hall magnetic ring, the magnetic ring sleeve is threadedly connected to the shaft, and the Hall magnetic ring is sleeved and fixed on the outer periphery of the magnetic ring sleeve and is distributed opposite to the rotor magnetic pole.

[0010] Optionally, the annular outer side wall of the magnetic ring sleeve includes an arc-shaped first cylindrical surface and a planar first flat surface, and the annular inner side wall of the Hall magnetic ring includes a second cylindrical surface fitting with the first cylindrical surface and a second flat surface fitting with the first flat surface.

[0011] Optionally, the rotor assembly further includes an adjusting shim, which is sleeved on the outer circumference of the rotating shaft, and is disposed between the rotor magnetic pole and the magnetic ring assembly.

[0012] Optionally, the adjusting shim includes a C-shaped adjusting shim body, and a locking arc that fits against the outer sidewall of the rotating shaft is provided on the inner side of the adjusting shim body.

[0013] Optionally, there are at least two locking arcs, which are spaced along the circumferential direction of the adjusting shim body, and the centers of all the locking arcs coincide.

[0014] Optionally, the adjusting shim body is provided with a disassembly through hole.

[0015] Through the above solution, the beneficial effects of the brushless DC motor provided by this application are as follows:

[0016] In the brushless DC motor of this application, the rotor assembly includes a rotating shaft, a rotor magnetic pole and a magnetic ring assembly. Among them, the rotor magnetic pole is sleeved on the outer circumference of the rotating shaft, the magnetic ring assembly is disposed at the end of the rotating shaft, and the magnetic ring assembly is threadedly connected to the rotating shaft. During use, the magnetic ring assembly can be rotated through the threaded structure to adjust the radial deflection angle between the magnetic ring assembly and the rotor magnetic pole, thereby changing the commutation deflection angle of the motor Hall electromotive force relative to the armature back electromotive force, achieving the effect of adjustable motor performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of this application. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0018] Figure 1 It is a schematic structural diagram of a brushless DC motor provided by an embodiment of this application;

[0019] Figure 2 It is a schematic structural diagram of a rotor assembly provided by an embodiment of this application;

[0020] Figure 3 It is for Figure 2 a schematic structural diagram of the sleeve in the rotor assembly shown cooperating with the Hall magnetic ring;

[0021] Figure 4 It is for Figure 2 a schematic structural diagram of the sleeve in the rotor assembly shown;

[0022] Figure 5 It is for Figure 2 a schematic structural diagram of the adjusting shim in the rotor assembly shown;

[0023] Figure 6 A structural schematic diagram of a stator assembly provided by an embodiment of the present application;

[0024] Figure 7 is Figure 6 A partial structural schematic diagram of the stator core in the stator assembly shown;

[0025] Figure 8 A schematic diagram of the brushless DC motor in the present application in the magnetized state;

[0026] Figure 9 A schematic diagram of the brushless DC motor in the present application in the state of adjusting the commutation deflection angle after magnetization;

[0027] Figure 10 A schematic diagram of the commutation deflection angle of the motor Hall electromotive force relative to the armature back electromotive force.

[0028] Figures 1 - 10 The reference signs in

[0029] 1 - screw, 2 - rotor assembly, 21 - rotating shaft, 22 - bearing, 23 - rotor pole, 24 - sleeve, 25 - Hall magnetic ring, 26 - magnetic ring sleeve, 261 - internal thread, 262 - first cylindrical surface, 263 - first flat surface, 27 - adjusting gasket, 271 - assembly end, 272 - locking arc, 273 - disassembly through hole, 3 - wave washer, 4 - front end cover, 5 - stator assembly, 51 - three-phase wire, 52 - stator core, 521 - auxiliary groove, 53 - insulation sheath, 54 - three-phase winding, 6 - rear end cover, 7 - countersunk head screw, 8 - T-shaped gasket, 9 - washer, 10 - rear end cover insulation washer, 11 - Hall plate, 12 - wire protection sleeve. Specific embodiments

[0030] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0031] Please refer to Figure 1 , the brushless DC motor provided by the present application may include the following components: rotor assembly 2, stator assembly 5, and end cover assembly.

[0032] Please refer to Figure 2, the rotor assembly 2 includes a rotating shaft 21, rotor magnetic poles 23, and a magnetic ring assembly. Among them, the rotating shaft 21 is pivotally mounted on the end cover assembly, and the rotating shaft 21 can rotate around its own axis. The rotor magnetic poles 23 and the stator assembly 5 jointly form the motor magnetic circuit. The rotor magnetic poles 23 are sleeved on the outer periphery of the rotating shaft 21 and can rotate synchronously with the rotating shaft 21. During actual installation, a sleeve 24 can be provided. The inner side of the sleeve 24 is fixed to the rotating shaft 21, and the outer side of the sleeve 24 is fixed to the rotor magnetic poles 23, so that the rotor magnetic poles 23 are indirectly fixed to the rotating shaft 21. The magnetic ring assembly is arranged at the end of the rotating shaft 21. The magnetic ring assembly is threadedly connected to the rotating shaft 21. By controlling the rotation of the magnetic ring assembly, the position of the magnetic ring assembly in the axial direction of the rotating shaft 21 can be adjusted to achieve the purpose of adjusting the angle of the magnetic ring assembly.

[0033] Among them, in one embodiment, please refer to Figure 3 , the magnetic ring assembly includes a magnetic ring sleeve 26 and a Hall magnetic ring 25. The internal thread 261 of the magnetic ring sleeve 26 is threadedly fastened to the corresponding external thread of the rotating shaft 21, and axial adjustment is achieved through the thread structure. The Hall magnetic ring 25 is sleeved and fixed on the outer periphery of the magnetic ring sleeve 26 and is distributed opposite to the rotor magnetic poles 23. The Hall magnetic ring 25 can rotate a certain angle according to performance requirements, and a certain commutation deflection angle β (radial) is achieved between the polarities of the Hall magnetic ring 25 and the rotor magnetic poles 23.

[0034] During actual assembly, the magnetic ring sleeve 26 and the Hall magnetic ring 25 can be fixed in various ways. For example, in one embodiment, please refer to Figure 4 , the annular outer side wall of the magnetic ring sleeve 26 includes an arc-shaped first cylindrical surface 262 and a planar first flat surface 263. Correspondingly, the annular inner side wall of the Hall magnetic ring 25 includes a second cylindrical surface that fits the first cylindrical surface 262 and a second flat surface that fits the first flat surface 263. The first flat surface 263 of the magnetic ring sleeve 26 effectively prevents the rotation of the Hall magnetic ring 25. For another example, in another embodiment, the magnetic ring sleeve 26 and the Hall magnetic ring 25 are fixed by interference fit, or bonding, or injection molding as a whole, or other means.

[0035] Furthermore, in one embodiment, the rotor assembly 2 further includes an adjusting gasket 27. The adjusting gasket 27 is sleeved on the outer periphery of the rotating shaft 21, and the adjusting gasket 27 is arranged between the rotor magnetic poles 23 and the magnetic ring assembly. Specifically, the adjusting gasket 27 can be stuck in the relief groove of the rotating shaft 21. The adjusting gasket 27 plays a role of axial limit and fixation. One side of the adjusting gasket 27 is in contact with the rotor magnetic poles 23 and / or the sleeve 24, and the other side of the adjusting gasket 27 is in contact with the magnetic ring assembly. Different thicknesses of the adjusting gasket 27 can be selected according to the motor performance requirements to adjust the radial deflection angle of the Hall magnetic ring 25 relative to the rotor magnetic poles 23. In terms of material selection, the adjusting gasket 27 needs to have elasticity, and it can rebound after being installed. The deformation amount is large during the assembly process. Preferably, it is a non-metallic part and has a gasket with wear-resistant and temperature-resistant characteristics.

[0036] Optionally, in one embodiment, for the convenience of the user to change the total thickness of the adjusting gasket 27, please refer to Figure 5 , the adjusting gasket 27 includes a C-shaped adjusting gasket body, and a locking arc 272 that fits against the outer sidewall of the rotating shaft 21 is provided on the inner side of the adjusting gasket body. During use, there is no need to disassemble and assemble the magnetic ring assembly, and the adjusting gasket body can be snapped into the relief groove from the outside of the rotating shaft 21 through the opening. After the adjusting gasket 27 is assembled into the relief groove, the locking arc 272 locks the rotating shaft 21 to prevent the adjusting gasket 27 from moving radially.

[0037] Optionally, in one embodiment, there are at least two locking arcs 272, and the locking arcs 272 are spaced circumferentially along the adjusting gasket body, and the centers of all the locking arcs 272 coincide. For example, the end of the adjusting gasket body near the opening is the assembly end 271, and three concentric locking arcs 272 are provided at the two assembly ends 271 and the middle position of the adjusting gasket body.

[0038] Optionally, in one embodiment, the adjusting gasket body is provided with a disassembly through hole 273. Specifically, when the assembled adjusting gasket 27 needs to be adjusted due to inappropriate thickness, the disassembly through hole 273 is used for disassembly.

[0039] The stator assembly 5 is sleeved on the outer periphery of the rotor assembly 2 and is used to form an inverter excitation magnetic field. There are various choices for the structure of the stator assembly 5. For example, please refer to Figure 6 , the stator assembly 5 includes a three-phase winding 54, three-phase wires 51, a stator core 52, and an insulating sheath 53; among them, the three-phase windings 54 of U, V, and W are wound in a triangular or star-shaped winding, the three-phase windings 54 are connected to the three-phase wires 51 of U, V, and W, and the stator core 52 fixes the three-phase windings 54 and forms the motor magnetic circuit. Please refer to Figure 7 , the stator core 52 can be provided with auxiliary grooves 521 for reducing the motor orientation torque and effectively improving the cogging torque. The insulating sheath 53 functions to insulate the armature circuit.

[0040] The end cover assembly is used to encapsulate the rotor assembly 2 inside itself. There are various choices for the structure of the end cover assembly. For example, the end cover assembly includes a front end cover 4 and a rear end cover 6. The front end cover 4, the stator assembly 5, and the rear end cover 6 are arranged in sequence along the axial direction of the rotating shaft 21. The rotor assembly 2 is fixed in the bearing chambers of the front end cover 4 and the rear end cover 6 through two bearings 22 (front bearing and rear bearing). The bearing 22 can specifically adopt a ball bearing, which functions to support the rotation of the rotor assembly 2 and bear the radial and axial loads. The wave washer 3 is assembled between the front end face of the front end cover 4 and the front bearing 22 for adjusting the axial movement of the motor. During actual assembly, screws 1 can be set to pass through the rear end cover 6, the stator assembly 5, and the front end cover 4 in sequence to lock and fix the motor.

[0041] Optionally, a Hall plate 11 and a wire protection sleeve 12 are fixed on the rear end cover 6. Among them, the Hall plate 11 is used to detect the polarity and position of the rotor magnetic pole 23, and the wire protection sleeve 12 is embedded and assembled in the rear end cover 6 and is used to constrain the wire harness of the Hall plate 11. During actual assembly, the Hall plate 11 can be fixed to the rear end cover 6 through a fastener assembly. The fastener assembly can include a countersunk screw 7 for fixing the Hall plate 11 to the rear end cover 6, a T-shaped gasket 8 for limiting and assisting the fixation of the countersunk screw 7, a washer 9 for insulating and supporting the Hall plate 11 and the rear end cover 6, and a rear end cover insulating washer 10 for electrical insulation.

[0042] Taking the brushless DC motor adopting the above structure as an example, the principle of adjusting the radial deflection angle between the Hall magnetic ring 25 and the rotor magnetic pole 23 will be described:

[0043] First, before the rotor assembly 2 is pressed into the two bearings 22, the rotor magnetic pole 23 and the Hall magnetic ring 25 are radially magnetized with the same magnetizing head. Finally, there is no deflection angle between the polarities of the formed Hall magnetic ring 25 and the rotor magnetic pole 23. At this time, the structure of the rotor assembly 2 and the magnetic ring assembly is as Figure 8 shown.

[0044] Then, according to the required different commutation deflection angles β (advanced or lagged), adjusting gaskets 27 with different thickness specifications are inserted into the relief groove of the rotating shaft 21. After that, the magnetic ring assembly can be rotated so that the end face of the magnetic ring assembly is in close contact with the end face of the adjusting gasket 27. At this time, the structure of the rotor assembly 2 and the magnetic ring assembly is as Figure 9 shown. Because the insertion of the adjusting gasket 27 causes the rotation of the Hall magnetic ring 25, and there is a corresponding relationship between the thickness of the adjusting gasket 27 and the rotation angle of the Hall magnetic ring 25, the commutation deflection angle β of the motor Hall electromotive force relative to the armature back electromotive force can be adjusted, and finally the motor performance can be adjusted.

[0045] As can be seen from the above embodiments, the beneficial effects of the brushless DC motor provided by this application are as follows:

[0046] The brushless DC motor provided by this application has the characteristics of low noise and adjustable performance. By rotating the Hall magnetic ring 25, the radial deflection angle between the Hall magnetic ring 25 and the rotor magnetic pole 23 can be adjusted, so as to change the commutation deflection angle β of the motor Hall electromotive force relative to the armature back electromotive force, and achieve the effect of adjustable motor performance. In addition, through the electromagnetic induction of the radial magnetic field of the Hall magnetic ring 25, away from the stator assembly 5 axially, the Hall is away from the traditional temperature rise area and the electromagnetic field concentration area, improving the stability of the Hall signal and the service life of the Hall magnetic ring 25.

[0047] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. The same and similar parts among the embodiments can be referred to each other.

[0048] The above has introduced the brushless DC motor provided by the present application in detail. Specific examples are used in this article to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of the present application, several improvements and modifications can still be made to the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. A brushless DC motor, characterized in that, It includes a rotor assembly (2), and the rotor assembly (2) includes a rotatable rotating shaft (21), rotor magnetic poles (23) sleeved on the outer periphery of the rotating shaft (21), and a magnetic ring assembly arranged at the end of the rotating shaft (21), and the magnetic ring assembly is threadedly connected to the rotating shaft (21); The magnetic ring assembly includes a magnetic ring sleeve (26) and a Hall magnetic ring (25), the magnetic ring sleeve (26) is threadedly connected to the rotating shaft (21), and the Hall magnetic ring (25) is sleeved and fixed on the outer periphery of the magnetic ring sleeve (26) and is distributed opposite to the rotor magnetic poles (23); The annular outer side wall of the magnetic ring sleeve (26) includes an arc-shaped first cylindrical surface (262) and a flat first flat surface (263), and the annular inner side wall of the Hall magnetic ring (25) includes a second cylindrical surface that fits the first cylindrical surface (262) and a second flat surface that fits the first flat surface (263); The rotor assembly (2) further includes an adjusting gasket (27), the adjusting gasket (27) is sleeved on the outer periphery of the rotating shaft (21), and the adjusting gasket (27) is arranged between the rotor magnetic poles (23) and the magnetic ring assembly; The adjusting gasket (27) includes a C-shaped adjusting gasket body, and a locking arc (272) that fits the outer side wall of the rotating shaft (21) is arranged on the inner side of the adjusting gasket body; 2. The brushless DC motor according to claim 1, wherein The brushless DC motor further includes a stator assembly (5) sleeved on the outer periphery of the rotor assembly (2), and the stator assembly (5) includes an insulating sheath (53), a stator core (52) provided with auxiliary grooves (521), and a three-phase winding (54) wound on the stator core (52); 3. The brushless DC motor according to claim 2, wherein The brushless DC motor further includes a front end cover (4) and a rear end cover (6) respectively arranged at the front end and the rear end of the stator assembly (5), the front end and the rear end of the rotating shaft (21) are pivotally installed on the front end cover (4) and the rear end cover (6) through a front bearing and a rear bearing respectively, and a wave washer (3) that abuts against the end face of the front bearing is arranged in the bearing chamber of the front end cover (4); 4. The brushless DC motor according to claim 1, wherein There are at least two locking arcs (272), the locking arcs (272) are circumferentially spaced along the adjusting gasket body, and the centers of all the locking arcs (272) coincide; 5. The brushless DC motor according to claim 1, wherein The adjusting gasket body is provided with a disassembly through hole (273).

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