Momentum wheel based on PCB motor

Abstract

The invention discloses a momentum wheel based on a PCB motor, and the momentum wheel comprises a housing, and a rotating shaft, stators and rotors which are arranged in the housing, the stators are parallel to the rotors, the rotating shaft is sleeved with the stators, the stators are fixedly installed on the housing, the stators are PCBs, the stators are provided with a plurality of coils which are arranged in the circumferential direction, and one or two rotors are arranged in the axial direction of the stators. The rotors are located on the two sides of the stator respectively and fixedly installed on the periphery of the rotating shaft, and the rotors are permanent magnets. The stator coil is manufactured by adopting the PCB technology, and the stator structure is flat and is matched with an axial magnetic circuit, so that the axial structure of the motor is more compact, and the size is greatly reduced; the stator coil has no iron core structure, so that the whole stator is greatly lightened; the permanent magnets of the rotor are made of neodymium iron boron materials, and compared with ferrite materials with weak magnetic force, the torque generated by the same current is larger; the size of the single-side rotor is smaller, so that the momentum wheel is lighter and thinner; the axial magnetic field directions of the permanent magnets on the two sides of the stator are the same when the two rotors are used, a superimposed magnetic field formed at the coil is stronger than the magnetic field of the single-side rotor, the magnetic field generated by the stator coil can be fully utilized by the double-side rotor structure, and large torque can be provided under small current.

Description

Technical Field

[0001] The invention relates to the technical field of momentum wheels, and in particular to a momentum wheel based on a PCB motor. Background Art

[0002] The momentum wheel is an important attitude control device for micro-nano satellites. In order to maximize the use of space and reduce launch costs in the design of micro-nano satellites, the weight and size of the momentum wheel need to be considered.

[0003] The power source of the existing momentum wheel design mainly uses a brushless DC motor composed of a housing, a stator and a rotor. The stator of the motor is composed of a coil and an iron core, and the rotor is a permanent magnet. The coil and the iron core of the motor occupy a large part of the total weight and volume of the motor, and do not generate angular momentum, which is not conducive to the miniaturization and lightweight of the momentum wheel. Summary of the invention

[0004] In order to solve the problems existing in the above-mentioned technology and reduce the weight and volume of the momentum wheel, the present invention proposes a momentum wheel based on a PCB motor, including a shell and a rotating shaft, a stator and a rotor arranged inside, the stator and the rotor are parallel to each other, the rotating shaft outer shell is connected to the stator, the stator is fixedly installed on the shell, the stator is a PCB board, the stator is provided with a plurality of circumferentially arranged coils, one or two rotors are arranged in the axial direction of the stator, the rotor is fixedly installed on the periphery of the rotating shaft, and the rotors are located on both sides of the stator in the case of double rotors.

[0005] The rotor is a permanent magnet, which is a flat ring structure and is made of neodymium iron boron material. The magnetic field direction of the rotor is radial. The rotor is fixedly installed on the periphery of the rotating shaft. In the case of a double rotor, the opposite magnetic poles of the rotors on both sides of the stator are opposite.

[0006] The stator coil is manufactured using PCB technology. The stator structure is flat, which cooperates with the axial magnetic circuit to make the axial structure of the motor more compact and greatly reduce its size. The stator coil has no iron core structure, which greatly reduces the overall weight of the stator. The permanent magnet rotor can be made of neodymium iron boron material, which can generate greater torque with the same current compared to ferrite materials with weaker magnetic force. The single-sided rotor has a smaller volume, making the momentum wheel thinner. In the case of dual rotors, the axial magnetic fields of the permanent magnets on both sides of the stator are in the same direction, and the superimposed magnetic field formed at the coil is stronger than that of the single-sided rotor. The double-sided rotor structure can make full use of the magnetic field generated by the stator coil and can provide greater torque at a smaller current.

[0007] Furthermore, the permanent magnet is an integrated type, and is manufactured by multi-pole magnetization of a flat annular permanent magnet.

[0008] Furthermore, in order to reduce manufacturing costs, the permanent magnet can be a split type, which is composed of multiple permanent magnets. The shape of the permanent magnet can be a sector ring, rectangle, trapezoid, triangle, etc.

[0009] Furthermore, in order to increase the motor torque and the response speed of the momentum wheel, more than one stator may be provided. When there are multiple stators, the rotor and the stator are interlaced and stacked, and the opposite magnetic poles of the rotor on both sides of each stator are opposite.

[0010] Furthermore, in order to increase the mechanical strength of the rotor, metal or other materials may be used to reinforce and fix the stator.

[0011] Furthermore, the coil is composed of coils distributed on the PCB layer and axially arranged and connected to each other by circuits.

[0012] Furthermore, in order to increase the efficiency of the momentum wheel, the interior of the housing may be a vacuum environment.

[0013] Furthermore, the stator can be sleeved to the periphery of the rotating shaft through a bearing.

[0014] Furthermore, the stator and the rotating shaft may not be connected via a bearing, and a gap is left between the stator and the rotating shaft.

[0015] Furthermore, in order to more accurately control the operation of the momentum wheel, sensors such as encoders and Hall elements may be installed to obtain the state of the momentum wheel. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic cross-sectional view of a momentum wheel based on a PCB motor according to the present invention

[0017] Figure 2 A schematic cross-sectional view of a momentum wheel based on a PCB motor according to the present invention

[0018] Figure 3 A schematic diagram of a rotor cross section in the present invention

[0019] Figure 4 A schematic diagram of a rotor cross section in the present invention

[0020] exist Figure 1 , Figure 2 In the figure, 1 is the housing, 2 is the rotor, 3 is the stator, 4 is the bearing, and 5 is the shaft.

[0021] exist Figure 3 In the figure, 1 is a rotor reinforcement metal ring, 2 is a transition metal ring, and 3 is a split permanent magnet.

[0022] exist Figure 4 In the figure, 1 is a rotor reinforcement metal ring, 2 is a transition metal ring, and 3 is an integrated permanent magnet. DETAILED DESCRIPTION

[0023] It should be noted that the embodiments of the present invention and the features of the embodiments can be combined with each other without conflict. The embodiments are only for facilitating the understanding of the present invention and cannot be understood as limiting the present invention. Any modifications, equivalent substitutions, improvements, etc. made based on the principles and ideas of the present invention should be included in the scope of protection of the present invention.

[0024] It should be noted that the directions or positional relationships indicated by terms such as “inside”, “outside”, “up”, “down”, “left” and “right” are based on the directions or positional relationships shown in the drawings and are only for the convenience of describing the present invention. They do not imply that the components or the whole of the present invention must have a specific orientation and should not be understood as limitations on the present invention.

[0025] It should be noted that terms such as "install", "fix", "connect", and "set" 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 an electrical connection or a mechanical connection. Technicians should understand the above terms according to the specific circumstances.

[0026] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0027] like Figure 1 As shown, the present invention proposes a momentum wheel based on a PCB motor, including a shell and a rotating shaft, a stator and a rotor arranged inside. The stator leads out a wire through the part of the PCB extending out of the shell. The stator and the rotor are parallel to each other. The rotating shaft outer shell engages the stator, and the stator is fixedly installed on the shell. The stator is a PCB board. The stator is provided with a plurality of circumferentially arranged coils. One or two rotors are arranged in the axial direction of the stator. The rotor is fixedly installed on the periphery of the rotating shaft. In the case of double rotors, the rotors are respectively located on both sides of the stator.

[0028] like Figure 3 , Figure 4 As shown, the rotor is a permanent magnet, which is a flat ring structure made of neodymium iron boron material. The magnetic field direction of the rotor is radial. The rotor is fixedly installed on the periphery of the rotating shaft. In the case of a double rotor, the opposite magnetic poles of the rotors on both sides of the stator are opposite, so that the permanent magnets on both sides of the stator form a magnetic field with the direction of the magnetic flux lines perpendicular to the plane where the stator is located. In order to ensure that the magnetic flux of the coil is fully utilized, the difference between the inner and outer diameters of the permanent magnet should not be less than twice the radial length of the coil.

[0029] Considering that the size of a 1U cube satellite is 100mm*100mm*100mm, the shell diameter is 65mm, the shell height is 17.5mm, the shell thickness is 1mm, and the shell material is stainless steel. The rotor diameter is 60mm, and there is a ring-shaped reinforced iron plate on the side of the rotor facing away from the stator, with an outer diameter of 62mm, an inner diameter of 9mm, and a thickness of 0.5mm. There is a reinforced metal ring on the periphery of the rotor, which is 4mm high and 2mm thick. The rotor and the shaft are fixed by a transition metal ring, which is 3.5mm thick. The transition metal ring and the reinforcement material are silicon steel or stainless steel.

[0030] The stator PCB material is FR-4, with a thickness of 1.6mm and a 6-layer board.

[0031] The gap between the permanent magnet and the stator should be minimized, and the deformation of the PCB should be fully considered, which can be 0.4mm.

[0032] The stator is provided with a plurality of circumferentially arranged multi-layer coils, and the multi-layer coils are composed of a plurality of axially arranged multi-turn planar coils distributed on a PCB layer and connected to each other in a circuit.

[0033] The permanent magnets, the permanent magnets and the fixed iron ring, the permanent magnets and the reinforcement iron plate, and the permanent magnets and the transition metal ring are fixed with adhesives. The reinforcement iron plate and the fixed iron ring, and the transition metal ring and the rotating shaft can be fixed with adhesives or welding.

[0034] The permanent magnet is made of 8 fan-shaped NdFeB magnets. The permanent magnet ring has an outer diameter of 60mm, an inner diameter of 10mm and a thickness of 5mm.

[0035] The stator is provided with 6 6-layer multi-turn isosceles trapezoidal stator coils with a radial length of 25 mm, and the center position of the coil corresponds to the center of the permanent magnet. Lead wires are drawn out from the part of the PCB extending out of the housing and connected to the brushless motor driver.

[0036] The diameter of the shaft is 5mm. The shaft passes through the stator. A certain gap is left between the stator and the shaft to avoid friction. The width of the gap can be 0.5mm.

[0037] Since the embodiment has a high requirement for volume, the embodiment will be somewhat different from the attached drawings. A central hole will be opened on the upper and lower surfaces of the shell for installing the bearing. The embodiment uses a bearing with an inner diameter of 5mm, an outer diameter of 8mm, and a thickness of 2mm. The bearing is embedded in the shell, and the outer edge is flush with the shell.

[0038] In order to reduce the protruding thickness of the Hall element, a hole is opened at a suitable position on the PCB stator, the SOT-23 packaged Hall element is invertedly soldered on the PCB stator, and the wire is led out from the part of the PCB that extends out of the shell.

Claims

1. A momentum wheel based on a PCB motor, characterized in that: It includes an outer shell and a rotating shaft, a stator and a rotor arranged inside. The stator and the rotor are parallel to each other. The outer shell of the rotating shaft engages the stator. The stator is fixedly installed on the outer shell. The stator is a PCB board. The stator is provided with a plurality of circumferentially arranged coils. One or two rotors are arranged in the axial direction of the stator. In the case of dual rotors, the rotors are respectively located on both sides of the stator. The rotors are fixedly installed on the periphery of the rotating shaft. The rotor is a permanent magnet. The magnetic field direction of the rotor is radial. In the case of dual rotors, the magnetic poles of the rotors on both sides of the stator are opposite.

2. A momentum wheel based on a PCB motor according to claim 1, characterized in that: The permanent magnet is an integrated flat ring structure, which is manufactured by multi-pole magnetization of a flat ring permanent magnet.

3. The momentum wheel based on a PCB motor according to claim 1, characterized in that: The permanent magnet is a split flat ring structure, which is composed of multiple permanent magnets. The shape of the permanent magnet can be a fan ring, rectangle, trapezoid, triangle, etc.

4. The momentum wheel based on a PCB motor according to claim 1, characterized in that: More than one stator is provided, and the rotor and the stator are interlaced and stacked with each other, and the magnetic poles of the rotors on both sides of each stator are opposite to each other.

5. The momentum wheel based on a PCB motor according to claim 1, characterized in that: Use metal or other materials to reinforce and fix the stator.

6. The momentum wheel based on a PCB motor according to claim 1, characterized in that: The coil is composed of coils distributed on the PCB layer and axially arranged and connected to each other by circuits.

7. The momentum wheel based on a PCB motor according to claim 1, characterized in that: The inside of the shell is a vacuum environment.

8. The momentum wheel based on a PCB motor according to claim 1, characterized in that: The stator is sleeved to the outer periphery of the rotating shaft through a bearing.

9. The momentum wheel based on a PCB motor according to claim 1, characterized in that: The stator and the rotating shaft are not connected through a bearing, and a gap is left between the stator and the rotating shaft.

10. The momentum wheel based on a PCB motor according to claim 1, characterized in that: Install encoders, Hall elements and other sensors to obtain the status of the momentum wheel.

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