A counter-rotating dual-rotor brushless DC motor

Abstract

This invention discloses a counter-rotating dual-rotor brushless DC motor, characterized by a basic unit of the drive mechanism. This unit comprises four electromagnetic windings with a total of eight electromagnetic poles, six permanent magnets on the upper rotor, and six permanent magnets on the lower rotor, totaling twelve permanent magnets. When using independent iron cores, two of the four electromagnetic windings are placed radially, and the other two are placed axially. The two poles of the radially placed electromagnetic windings drive the same rotor, while one pole of the two axially placed electromagnetic windings drives the upper rotor, and the other pole drives the lower rotor. This invention requires only one stator to drive both rotors, reducing weight, saving costs, and offering a simple structure and easy control.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of motor technology, in particular to a double-rotor brushless DC motor. BACKGROUND

[0002] The existing motor is generally composed of a stator and a rotor. A double-rotor motor has also been invented, which can drive two rotors with one stator. However, the existing double-rotor motor adopts two-layer windings, the thickness of the core is relatively thick, the weight is relatively heavy, and the control is relatively complex. SUMMARY

[0003] The present application provides a double-rotor brushless DC motor, which can drive two rotors simultaneously with one stator, thereby reducing the weight and saving the cost, and the structure is simple and easy to control.

[0004] The present application is implemented by adopting the following technical solutions:

[0005] The double-rotor brushless DC motor comprises a driving mechanism and a synchronization mechanism, the driving mechanism comprises a stator and two rotors symmetrically arranged above and below, the rotor is composed of a rotor disc and six permanent magnets, the six permanent magnets form a basic unit, the stator is arranged between the two rotors, four electromagnetic poles corresponding to the rotor on the same side are arranged on the upper and lower sides of the stator, and the fundamental wave magnetic potential of the four electromagnetic poles facing the same side rotor differs by 90° electric angle.

[0006] The two rotors above and below share 12 permanent magnets, and the stator has a total of 8 electromagnetic poles, and the fundamental wave magnetic potential of the four electromagnetic poles facing the same side rotor differs by 90° electric angle.

[0007] Preferably, the stator comprises four electromagnetic windings, the electromagnetic windings have independent cores, two electromagnetic windings of the four electromagnetic windings are radially arranged, and the other two electromagnetic windings are axially arranged, the two radially arranged electromagnetic windings are arranged side by side above and below, the two electromagnetic poles of the radially arranged electromagnetic windings face the same side rotor, the two axially arranged electromagnetic windings are arranged on the two sides of the radially arranged electromagnetic windings, the electromagnetic pole at the upper end of the axially arranged electromagnetic winding faces the upper rotor, and the electromagnetic pole at the lower end of the axially arranged electromagnetic winding faces the lower rotor. The two electromagnetic poles of the radially arranged electromagnetic winding above and the electromagnetic poles at the upper end of the two axially arranged electromagnetic windings form four electromagnetic poles facing the upper rotor, and the four electromagnetic poles are used for driving the upper rotor; the two electromagnetic poles of the radially arranged electromagnetic winding below and the electromagnetic poles at the lower end of the two axially arranged electromagnetic windings form four electromagnetic poles facing the lower rotor, and the four electromagnetic poles are used for driving the lower rotor. Each electromagnetic winding has an independent core.

[0008] As a preference, the winding method of the coil on the electromagnetic winding of the stator with an integral core is the same as the winding method of the coil on the electromagnetic winding of the stator with independent cores.

[0009] As a preference, when the pole pair number of the driving mechanism needs to be increased, the number of the permanent magnets of the rotor and the number of the electromagnetic poles on the same side of the stator are increased in a ratio of 6:4.

[0010] As a preference, the synchronous mechanism is arranged between two rotors, the two rotors are connected through the synchronous mechanism, and the stator is used to drive the two rotors to rotate in opposite directions. The synchronous mechanism comprises two linkage gears and at least one synchronous gear, one linkage gear is coaxially connected with the upper rotor, the other linkage gear is coaxially connected with the lower rotor, the linkage gears are arranged on a longitudinal shaft in a bearing sleeve, and the synchronous gear is arranged between the two linkage gears and meshes with the two linkage gears, and the synchronous gear is arranged on a transverse shaft in a bearing sleeve.

[0011] As a preference, the stator is mounted outside the synchronous mechanism.

[0012] As a preference, the axes of the two rotors are located on the same straight line.

[0013] The beneficial effects of the present application are: (1) the two rotors can drive the two rotors to rotate in opposite directions, the upper rotor and the lower rotor rotate at the same speed through a synchronous mechanism, only one stator is used, the weight is reduced, the cost is saved, the structure is simple, and the control is easy. (2) It is very suitable for application in multi-rotor aircraft, and can replace ordinary brushless DC motor, only one counter-rotating double-rotor brushless DC motor is needed to drive two propellers at the same time, and greater thrust can be obtained at the same speed, or the same thrust can be obtained at a lower speed, so that the multi-rotor aircraft has longer endurance time or greater load capacity. (3) It can be used to build a coaxial double-rotor helicopter based on electric drive, compared with the existing pure mechanical structure coaxial double-rotor helicopter, the coaxial double-rotor helicopter driven by the counter-rotating double-rotor brushless DC motor has a simpler structure and is easier to control, so that the helicopter can enter an electric drive hybrid power era. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a sectional view of the present embodiment;

[0015] Figure 2 is a structural schematic view of the rotor;

[0016] Figure 3 is a graph of the magnetic potential change of the stator and the rotor in a period;

[0017] Figure 4 is a cross-sectional view of the synchronization mechanism.

[0018] In the figure: 1, longitudinal axis, 2, linkage gear, 3, synchronization gear, 4, transverse axis, 5, electromagnetic winding, 6, rotor disc, 7, permanent magnet, 8, bearing, 9, synchronization mechanism housing. DETAILED DESCRIPTION

[0019] The technical solutions of the present application will be further described in detail below with examples and in conjunction with the drawings.

[0020] Example: The present example is a contra-rotating double-rotor brushless DC motor, as shown in Figure 1 , Figure 2 , Figure 3 , Figure 4 , which includes a driving mechanism and a synchronization mechanism, the driving mechanism includes two rotors arranged symmetrically up and down, the axes of the two rotors are located on the same straight line, and a stator is provided between the two rotors for driving the two rotors to rotate in opposite directions, the synchronization mechanism is arranged between the two rotors, the two rotors are connected through the synchronization mechanism, and the synchronization mechanism is used to enable the two rotors to rotate in opposite directions at the same speed.

[0021] Figure 1 The overall structure of the contra-rotating double-rotor brushless DC motor is shown.

[0022] Each rotor is composed of a rotor disc 6 and six permanent magnets 7, and the six permanent magnets 7 form a basic unit, and the two rotors together have 12 permanent magnets.

[0023] Figure 2 The structure of the rotor is shown, and the rotor is only composed of a rotor disc and permanent magnets.

[0024] A stator is provided between the two rotors, and the stator has four electromagnetic poles corresponding to the two rotors respectively, a total of 8 electromagnetic poles.

[0025] The fundamental wave magnetic potential of the four electromagnetic poles facing the same rotor differs by 90° electric angle.

[0026] Figure 3 The fundamental wave magnetic potential variation diagram of the electromagnetic winding 5 of the stator composed of a basic unit and the permanent magnet of the rotor interacting within one rotation period is shown, each group represents the situation within 8th of a period, and in Figure 3 , all N and S poles are exchanged without affecting the working efficiency, the left and right sides are exchanged without affecting the working efficiency, and the upper and lower parts are exchanged without affecting the working efficiency.

[0027] Since the fundamental wave magnetic potential of the four electromagnetic poles facing the same rotor differs by 90° electric angle, in order to achieve this goal, the stator coil must adopt a specific winding method, from Figure 3It can be seen that if the electromagnetic winding adopts independent core, the stator must have both the core axial winding and the core radial winding.

[0028] The stator includes four electromagnetic windings, when the electromagnetic winding has independent core, two of the four electromagnetic windings 5 are radially placed, and the other two are axially placed, the radially placed electromagnetic windings 5 and the axially placed electromagnetic windings 5 are alternately adjacent. The two poles of the radially placed electromagnetic windings 5 drive the same rotor, and the two axially placed electromagnetic windings 5 drive the upper rotor with one pole and the lower rotor with the other pole.

[0029] Figure 3 The independent core in the figure is only for the purpose of showing the working principle, when an integrated core is used, the winding direction of the coil is the same as when an independent core is used.

[0030] The six permanent magnets of each rotor and the four electromagnetic poles facing each rotor constitute the basic unit of electromagnetic drive, two rotors require a total of 12 permanent magnets, and the stator requires a total of 8 electromagnetic poles to drive the upper and lower rotors.

[0031] When a larger number of pole pairs is required, the number of permanent magnets and electromagnetic poles is increased synchronously according to the ratio of 6:4. When there is a special requirement to reduce the number of permanent magnets, the number of permanent magnets of each rotor should be at least greater than the corresponding number of electromagnetic poles.

[0032] The synchronous mechanism includes two linkage gears 2 and at least one synchronous gear 3, one linkage gear 2 is coaxially connected with the upper rotor, and the other linkage gear 2 is coaxially connected with the lower rotor, the linkage gear 2 is sleeved on the longitudinal shaft 1 arranged in the longitudinal direction through the bearing 8, the synchronous gear 3 is located between the two linkage gears 2 and engages with the two linkage gears 2, the synchronous gear 3 is sleeved on the transverse shaft 4 arranged in the transverse direction through the bearing 8. One end of the linkage gear is fixed with the housing 9 of the linkage mechanism through the bearing 8, and the other end is fixed with the longitudinal shaft through a bearing 8.

[0033] The stator is installed outside the synchronous mechanism.

[0034] The axes of the upper and lower rotors are located on the same straight line.

Claims

1. A contra-rotating brushless DC motor comprising a drive mechanism and a synchronization mechanism, characterized in that, The driving mechanism comprises a stator and two rotors symmetrically arranged above and below, the rotor is composed of a rotor disc (6) and six permanent magnets (7), the six permanent magnets (7) form a basic unit, the stator is arranged between the two rotors, four electromagnetic poles corresponding to the rotor on the same side are arranged on the upper and lower sides of the stator respectively, the fundamental wave magnetic potential of the four electromagnetic poles facing the rotor on the same side is different by 90° electric angle. The stator comprises four electromagnetic windings (5), the electromagnetic winding (5) has an independent core, two electromagnetic windings (5) in the four electromagnetic windings (5) are radially arranged, and the other two electromagnetic windings (5) are axially arranged, the two radially arranged electromagnetic windings (5) are arranged side by side above and below, the two electromagnetic poles of the radially arranged electromagnetic winding (5) face the rotor on the same side, the two axially arranged electromagnetic windings (5) are arranged on the two sides of the radially arranged electromagnetic winding (5), the electromagnetic pole at the upper end of the axially arranged electromagnetic winding (5) faces the upper rotor, and the electromagnetic pole at the lower end of the axially arranged electromagnetic winding (5) faces the lower rotor.

2. A contra-rotating brushless DC motor according to claim 1, wherein When the stator adopts an integrated core, the winding method of the coil on the electromagnetic winding (5) is the same as that when the stator adopts an independent core.

3. A contra-rotating brushless DC motor according to claim 1, wherein When it is necessary to increase the pole pair number of the driving mechanism, the number of permanent magnets (7) of the rotor and the number of electromagnetic poles on the same side of the stator are increased in a ratio of 6:

4.

4. A contra-rotating brushless DC motor according to claim 1, wherein The synchronous mechanism is arranged between the two rotors, the two rotors are connected through the synchronous mechanism, and the stator is used for driving the two rotors to relatively and reversely rotate.

5. A contra-rotating brushless DC motor according to claim 4, wherein The synchronous mechanism comprises two linkage gears (2) and at least one synchronous gear (3), one linkage gear (2) is coaxially connected with the upper rotor, the other linkage gear (2) is coaxially connected with the lower rotor, the linkage gear (2) is sleeved on the longitudinal shaft (1) arranged in the longitudinal direction through the bearing (8), the synchronous gear (3) is located between the two linkage gears (2) and meshes with the two linkage gears (2), and the synchronous gear (3) is sleeved on the transverse shaft (4) arranged in the transverse direction through the bearing (8).

6. A contra-rotating brushless DC motor according to claim 1, wherein The stator is mounted outside the synchronous mechanism.

7. A contra-rotating brushless DC motor according to claim 1, wherein The axes of the two rotors are located on the same straight line.

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