Stepper Motor

Abstract

The present invention provides a stepper motor, which includes a rotating shaft, a magnetic steel fixed to the outer peripheral side of the rotating shaft, and a winding unit sleeved on the rotating shaft and rotatably connected with the rotating shaft, the winding unit includes at least one winding and is spaced apart from the magnetic steel, and each of the windings is spaced apart from the magnetic steel; each winding includes a shell sleeved on the rotating shaft, a frame fixed to the shell, two first claw poles fixed to the two ends of the shell, two second claw poles fixed to the middle area of ​​the frame, and two coils wound around the frame and spaced apart; the opposite sides of the shell in each winding are provided with notches penetrating its side walls. The stepper motor in the present invention can increase the effective volume of the entire magnetic circuit, and the torque performance can also be improved by about 15%.

Description

Technical Field

[0001] The present invention relates to the field of motor technology, and in particular to a stepper motor used in a folding screen mobile phone. Background Art

[0002] Due to its compact structure, high efficiency, energy saving and consumption reduction, stepper motors have been widely used in most technical fields, such as electric motors, generators and folding.

[0003] In the folding field, Figure 1 As shown, the automatic folding hinge 101 used in the folding screen mobile phone 100 requires a stepper motor to implement. In order to achieve the lightness and thinness of the folding screen mobile phone 100, its thickness in the Z-axis direction needs to be further reduced, that is, the layout space in the Z-axis direction needs to be reduced, while the layout space in the Y-axis direction is relatively loose and does not need to be further reduced. Under the condition of limited layout space in the Z-axis direction, in order to ensure that the automatic folding of the folding screen mobile phone 100 is not affected, it is necessary to ensure that the output torque of the stepper motor is large enough.

[0004] In the related technology, combined Figure 2 and Figure 3 As shown, the motor 200 mainly includes a shaft 210, a magnet 220 fixed to the outer peripheral side of the shaft 210, a winding structure 230 sleeved on the shaft 210 and rotatingly connected with the shaft 210, and a flexible circuit board fixed to the winding structure 230 and electrically connected to the winding structure 230. The winding structure includes four winding groups 230, each winding group 230 includes a shell 2301 which is sleeved on the shaft 210 and surrounded by side walls, a bracket 2302 fixed to the inner side of the shell 2301, a first claw pole structure 2303 fixed to the shell 2301 and extending into the bracket 2302, a second claw pole structure 2304 fixed to the bracket 2302 and arranged opposite to the first claw pole structure 2303, a coil structure 2305 fixed to the outer side of the bracket 2302, and a winding cylinder 2306 fixed to the outer side of the bracket 2302. The outer shell 2301 is rotatably connected to the shaft 210 through a cover plate 2307 and a bearing body 2308. In order to limit the second claw pole structure 2304, a small notch 240 needs to be designed on the side of the shell 2301, and in order to allow the winding cylinder 2306 to pass through, a large notch 250 needs to be designed on the side of the shell 2301.

[0005] To sum up, the small notch 240 and the large notch 250 designed on the shell 2301 of the motor 200 in the related art are both for forming an avoidance position. This design method will make the volume of the magnet 220, the side wall of the shell 2301, the first claw pole structure 2303, the second claw pole structure 2304 and the coil structure 2305 also limited by the size in a single direction when the size of the motor 200 is limited in a single direction, thereby resulting in a smaller torque of the motor 200.

[0006] Therefore, it is necessary to provide a new stepping motor to solve the above technical problems. Summary of the invention

[0007] The purpose of the present invention is to provide a new stepping motor to solve the problem in the related art that the housing design of the motor leads to a small torque.

[0008] In order to achieve the above-mentioned object, the present invention provides a stepping motor, which comprises a rotating shaft, a magnetic steel fixed to the outer peripheral side of the rotating shaft, and a winding unit sleeved on the rotating shaft and rotatably connected to the rotating shaft, wherein the winding unit comprises at least one winding arranged along the axial direction of the rotating shaft, and each of the windings is spaced apart from the magnetic steel;

[0009] Each of the windings includes a shell that is sleeved on the rotating shaft and forms a rotational connection with the rotating shaft, a frame fixed on the inner side of the shell and coaxially arranged with the shell, two first claw poles respectively fixed at both ends of the shell, two second claw poles fixed at the middle area of ​​the frame and extending into the frame, and two coils respectively wound around the outer circumference of the frame and arranged at intervals; the shell is annular and surrounded by side walls, each of the second claw poles extends into the frame and forms a fixed connection with the frame, each of the first claw poles is arranged opposite to a corresponding one of the second claw poles and cooperates with each other, and each of the coils is located on the outside of a corresponding one of the first claw poles and a second claw pole; slots penetrating the side walls are opened on opposite sides of the shell in each of the windings.

[0010] Preferably, the two second claw poles in each of the windings are respectively embedded in the corresponding frame, and are integrally formed with the corresponding frame by insert injection molding.

[0011] Preferably, the stepper motor also includes a flexible circuit board fixed to the winding unit and electrically connected to the winding unit, the flexible circuit board is respectively fixed to the skeleton in each of the windings, and the flexible circuit board is respectively electrically connected to all the coils in each of the windings.

[0012] Preferably, the middle area of ​​the skeleton in each of the windings is provided with an extension portion that protrudes and extends and passes through the shell, and four winding poles that protrude and extend are provided at intervals on the side of the extension portion away from the skeleton, and the four winding poles are respectively inserted and fixed on the flexible circuit board; the two ends of the two coils in each of the windings are respectively wound around the four winding poles and are electrically connected to the flexible circuit board.

[0013] Preferably, the winding post and the extension portion in each winding are integrally formed with the frame by injection molding.

[0014] Preferably, the magnetic steel is a sintered magnetic steel.

[0015] Preferably, the magnetic steel includes a plurality of magnetic steels, the plurality of magnetic steels are arranged around the rotating shaft and fixed to the outer peripheral side of the rotating shaft, and the plurality of magnetic steels are arranged at intervals from each other.

[0016] Preferably, each of the first claw poles and each of the second claw poles includes an annular fixing portion and a plurality of bent portions extending from the inner periphery of the fixing portion along its axial direction, and the plurality of bent portions are arranged at intervals and all extend into the skeleton; the bent portion of each of the first claw poles is located between the two bent portions of the corresponding second claw pole, and the bent portion of each of the second claw poles is located between the two bent portions of the corresponding first claw pole.

[0017] Preferably, the inner side of the skeleton in each of the windings is provided with a plurality of grooves which are recessed inwardly, and the shapes of the plurality of grooves respectively match the plurality of bending portions of the first claw pole and the plurality of bending portions of the second claw pole, and the plurality of bending portions of the first claw pole and the plurality of bending portions of the second claw pole are respectively accommodated and fixed in the corresponding grooves.

[0018] Preferably, each of the first claw poles is integrally formed with the corresponding housing.

[0019] Preferably, the winding unit comprises a plurality of windings arranged along the axial direction of the rotating shaft, the shells in the plurality of windings are fixedly connected in sequence, and the corresponding notches in the plurality of windings are interconnected along the axial direction of the rotating shaft.

[0020] Preferably, the shell in each of the windings includes a first shell and a second shell which are hollow and overlapped with each other along the axial direction of the rotating shaft, and the notches are respectively arranged in the first shell and the second shell; the two outer windings also include a cover body which is fixed to the end of the first shell away from the second shell, and the first shell in the two outer windings is farther away from the other winding relative to the second shell, and the cover body is fixed to the rotating shaft through a bearing and forms a rotational connection with the rotating shaft, and the cover body is provided with an inwardly recessed notch at the position corresponding to the notch; the two first claw poles in each of the windings are respectively arranged at the end of the first shell and the second shell away from each other.

[0021] Compared with the related art, the stepper motor in the present invention achieves limitation by fixing the second claw pole to the frame, and opens slots penetrating the side walls of the shell on opposite sides to achieve avoidance in a single direction, so that the stepper motor can further expand the volume of the magnet, the first claw pole, the second claw pole and the coil under the same size. Although the volume of the side wall of the shell is reduced, on the whole, it releases the space of the effective magnetic circuit composed of the magnet and the coil, increases the effective volume of the entire magnetic circuit, and improves the torque performance by about 15%. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0023] Figure 1 A schematic diagram of the structure of a foldable screen mobile phone provided for related technologies;

[0024] Figure 2 A three-dimensional structural diagram of a stepper motor provided for related technology;

[0025] Figure 3 A schematic diagram of the structural decomposition of a stepper motor provided for related technology;

[0026] Figure 4 A schematic diagram of the three-dimensional structure of a stepping motor provided in an embodiment of the present invention;

[0027] Figure 5 A schematic diagram of the structural decomposition of a stepper motor provided in an embodiment of the present invention;

[0028] Figure 6 for Figure 4 AA line section view;

[0029] Figure 7 A schematic diagram of the structure of a skeleton in a stepping motor provided in an embodiment of the present invention.

[0030] Figures 4 to 7 In: 300, stepper motor; 1, shaft; 2, magnet; 3, winding; 31, shell; 311, notch; 312, first shell; 313, second shell; 314, shallow notch; 32, skeleton; 321, extension; 322, winding post; 323, groove; 33, first claw pole; 331, fixing portion; 332, bending portion; 34, second claw pole; 35, coil; 4, flexible circuit board; 5, cover; 51, notch; 6, bearing; 7, gasket. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The embodiment of the present invention provides a stepping motor 300, combined with Figures 4 to 7 As shown, it includes a rotating shaft 1, a magnetic steel 2 fixed to the outer peripheral side of the rotating shaft 1, a winding unit sleeved on the rotating shaft 1 and rotatingly connected with the rotating shaft 1, and a flexible circuit board 4 fixed to the winding unit and electrically connected to the winding unit. The winding unit includes at least one winding 3 arranged along the axial direction of the rotating shaft 1, and each winding 3 is spaced apart from the magnetic steel 2.

[0033] Among them, the magnet 2 is a sintered magnet, and the magnetic remanence of the magnet 2 is one of the factors affecting the torque performance of the stepper motor 300. Since the shape of the magnet 2 can be annular or can be formed by multiple magnets 2 to form a ring with a small diameter, if the magnet 2 is fixed by bonding, the magnetic remanence of the magnet 2 is low, which is not conducive to improving the torque performance of the stepper motor 300. The magnet 2 of this embodiment adopts a sintered magnet, and the magnetic remanence of the magnet 2 is increased by more than 50% compared with that by bonding, which can effectively improve the torque performance of the stepper motor 300 and is suitable for the case where the size of the stepper motor 300 is limited in a single direction.

[0034] Of course, fixing the magnet 2 by bonding also has advantages: mold imaging is easy to prepare, multi-pole magnetization is possible, simple and convenient, and conducive to mass production; using sintered magnets also has disadvantages: it cannot be directly molded and multi-pole magnetization is not possible, and it needs to go through slicing → magnetization → patching → grinding → powder removal → electroplating in sequence. The process is complex and immature, and the cost is high.

[0035] The magnetic steel 2 includes a plurality of magnetic steels 2, which are arranged around the rotating shaft 1 and fixed to the outer peripheral side of the rotating shaft 1, and the plurality of magnetic steels 2 are arranged at intervals from each other. In this embodiment, the magnetic steels 2 include eight and are arranged at equal intervals. Of course, the number of magnetic steels 2 can also be adaptively modified according to actual needs.

[0036] Specifically, each winding 3 includes a shell 31 which is sleeved on the rotating shaft 1 and forms a rotational connection with the rotating shaft 1, a skeleton 32 fixed on the inner side of the shell 31 and coaxially arranged with the shell 31, two first claw poles 33 respectively fixed at both ends of the shell 31, two second claw poles 34 fixed in the middle area of ​​the skeleton 32, and two coils 35 respectively wound around the outer circumference of the skeleton 32 and arranged at intervals. The shell 31 is annular and surrounded by side walls. Each second claw pole 34 extends into the skeleton 32 and forms a fixed connection with the skeleton 32. Each first claw pole 33 is arranged opposite to a corresponding second claw pole 34 and cooperates with each other. Each coil 35 is located on the outside of a corresponding first claw pole 33 and a second claw pole 34; the opposite sides of the shell 31 in each winding 3 are provided with slots 311 penetrating through its side walls.

[0037] The flexible circuit board 4 is fixed to the frame 32 in each winding 3 , and the flexible circuit board 4 is electrically connected to all the coils 35 in each winding 3 .

[0038] The middle area of ​​the skeleton 32 in each winding 3 is provided with an extension portion 321 that protrudes and extends and penetrates the shell 31. Four winding posts 322 that protrude and extend are provided at intervals on the side of the extension portion 321 away from the skeleton 32. The four winding posts 322 are respectively inserted and fixed on the flexible circuit board 4; the two ends of the two coils 35 in each winding 3 are respectively wound around the four winding posts 322 and form an electrical connection with the flexible circuit board 4.

[0039] The winding post 322 and the extension part 321 in each winding 3 are integrally formed with the frame 32 by injection molding. This design adopts the plastic pin integrally formed, cancels the metal pin insert integrally formed by injection molding in the related art, and avoids the disadvantages of the metal pin being unstable and easy to fall off in the case of small size.

[0040] Combination Figure 2 and Figure 3As shown, the coil structure 2305 and the first claw pole structure 2303 and the second claw pole structure 2304 of the motor 200 in the related art are separate parts, and the coil structure 2305 is wound and fixed on the bracket 2302. The four coil structures 2305 are installed in sequence, and the winding cylinders 2306 are uniformly arranged in one direction. The disadvantage is that a large notch 250 must be opened on the side wall of the shell 2301 for avoidance, which results in that the torque performance of the motor 200 cannot be fully improved and the side space is occupied. The bracket 2302 is injection molded, and its radial thickness needs to be at least 0.15 mm, which wastes the layout space.

[0041] In this embodiment, the two second claw poles 34 in each winding 3 are respectively embedded in the corresponding frame 32, and are integrally formed with the corresponding frame 32 by insert injection molding. In this design, the radial thickness of the frame 32 can be reduced to 0.08, which effectively increases the magnetic circuit space of the stepper motor 300, and the housing 31 is installed from both sides of the coil 35, so there is no need to open a large notch, and only a shallow notch 314 is needed to meet the assembly requirements, which effectively increases the side wall of the housing 31, so that the torque performance of the stepper motor 300 is effectively improved.

[0042] Each first claw pole 33 is integrally formed with the corresponding housing 31 .

[0043] Each first claw pole 33 and each second claw pole 34 includes an annular fixing portion 331 and a plurality of bent portions 332 extending from the inner periphery of the fixing portion 331 along its axial direction, and the plurality of bent portions 332 are arranged at intervals and extend into the frame 32; the bent portion 332 of each first claw pole 33 is located between the two bent portions 332 of the corresponding second claw pole 34, and the bent portion 332 of each second claw pole 34 is located between the two bent portions 332 of the corresponding first claw pole 33.

[0044] The fixing portion 331 of each first claw pole 33 is fixed to one end of the housing 31, and the fixing portion 331 of each second claw pole 34 is fixed to the middle area of ​​the corresponding frame 32. This design can ensure the stability of the first claw pole 33 and the second claw pole 34 and both can extend into the frame 32 to adapt to the corresponding coil 35.

[0045] The inner side of the frame 32 in each winding 3 is provided with a plurality of grooves 323 formed inwardly concave, and the shapes of the plurality of grooves 323 are matched with the plurality of bending portions 332 of the first claw pole 33 and the plurality of bending portions 332 of the second claw pole 34, respectively. The plurality of bending portions 332 of the first claw pole 33 and the plurality of bending portions 332 of the second claw pole 34 are respectively received and fixed in the corresponding grooves 323. In this design, the first claw pole 33 and the second claw pole 34 can be respectively limited by the grooves 323 designed on the frame 32.

[0046] Specifically, the winding unit includes a plurality of windings 3 arranged along the axial direction of the rotating shaft 1, the housings 31 in the plurality of windings 3 are fixedly connected in sequence, and the corresponding notches 311 in the plurality of windings 3 are interconnected along the axial direction of the rotating shaft 1. In this embodiment, the winding unit includes two windings 3.

[0047] The shell 31 in each winding 3 includes a first shell 312 and a second shell 313 which are hollow and overlap each other along the axial direction of the rotating shaft 1, and the notch 311 is respectively arranged on the first shell 312 and the second shell 313; the two outer windings 3 also include a cover 5 which is fixed to the end of the first shell 312 away from the second shell 313, the first shell 312 in the two outer windings 3 is farther away from the other winding 3 relative to the second shell 313, the cover 5 is fixed to the rotating shaft 1 through the bearing 6 and forms a rotational connection with the rotating shaft 1, and the cover 5 is provided with an inwardly recessed notch 51 at the position corresponding to the notch 311; the two first claw poles 33 in each winding 3 are respectively arranged at the end of the first shell 312 and the second shell 313 away from each other. This design not only facilitates the rotational connection between the shell 31 and the rotating shaft 1, but also facilitates the disassembly and assembly of the shell 31 and the design of the notch 311.

[0048] In addition, the stepper motor 300 further includes two spacers 7 which are sleeved on the rotating shaft 1 and spaced apart from each other, and the two spacers 7 are respectively in contact with the two ends of the magnetic steel 2. This design can strengthen the fixing strength between the magnetic steel 2 and the rotating shaft 1.

[0049] The stepper motor 300 in this embodiment can be applied to the automatic folding hinge of a folding screen mobile phone.

[0050] Compared with the related art, the stepper motor 300 in this embodiment achieves limiting by fixing the second claw pole 34 to the frame 32, and opens slots 311 penetrating the side walls of the shell 31 on opposite sides to achieve avoidance in a single direction, so that the stepper motor 300 can further expand the volume of the magnet 2, the first claw pole 33, the second claw pole 34 and the coil 35 under the same size. Although the volume of the side wall of the shell 31 is reduced, on the whole, it releases the space of the effective magnetic circuit composed of the magnet 2 and the coil 35, so that the effective volume of the entire magnetic circuit is increased, and the torque performance is also improved by about 15%.

[0051] The above description is only an implementation mode of the present invention. 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 invention, but these all belong to the protection scope of the present invention.

Claims

1. A stepping motor, characterized in that: The stepper motor includes a rotating shaft, a magnetic steel fixed to the outer peripheral side of the rotating shaft, and a winding unit sleeved on the rotating shaft and rotatably connected to the rotating shaft, wherein the winding unit includes at least one winding arranged along the axial direction of the rotating shaft, and each of the windings is spaced apart from the magnetic steel; Each of the windings includes a shell that is sleeved on the rotating shaft and forms a rotational connection with the rotating shaft, a frame fixed to the inner side of the shell and coaxially arranged with the shell, two first claw poles respectively fixed to the two ends of the shell, two second claw poles fixed to the middle area of ​​the frame, and two coils respectively wound around the outer circumference of the frame and arranged at intervals; the shell is annular and surrounded by side walls, each of the second claw poles extends into the frame and forms a fixed connection with the frame, each of the first claw poles is arranged opposite to a corresponding one of the second claw poles and cooperates with each other, and each of the coils is located on the outside of a corresponding one of the first claw poles and a second claw pole; the opposite sides of the shell in each of the windings are provided with slots penetrating the side walls.

2. The stepper motor according to claim 1, characterized in that: The two second claw poles in each of the windings are respectively embedded in the corresponding frame, and are integrally formed with the corresponding frame by insert injection molding.

3. The stepper motor according to claim 1, characterized in that: The stepper motor further includes a flexible circuit board fixed to the winding unit and electrically connected to the winding unit, the flexible circuit board is respectively fixed to the frame in each of the windings, and the flexible circuit board is respectively electrically connected to all the coils in each of the windings.

4. The stepping motor according to claim 3, characterized in that: The middle area of ​​the skeleton in each of the windings is provided with an extension portion that protrudes and extends and penetrates the shell, and four winding poles that protrude and extend are provided at intervals on the side of the extension portion away from the skeleton, and the four winding poles are respectively inserted and fixed on the flexible circuit board; the two ends of the two coils in each of the windings are respectively wound around the four winding poles and electrically connected to the flexible circuit board.

5. The stepping motor according to claim 4, characterized in that: The winding post and the extension portion in each winding are integrally formed with the frame by injection molding.

6. The stepping motor according to claim 1, characterized in that: The magnetic steel is a sintered magnetic steel.

7. The stepping motor according to claim 6, characterized in that: The magnetic steels include a plurality of magnetic steels, which are disposed around the rotating shaft and fixed to the outer peripheral side of the rotating shaft, and the plurality of magnetic steels are arranged at intervals from each other.

8. The stepper motor according to claim 1, characterized in that: Each of the first claw poles and each of the second claw poles includes an annular fixing portion and a plurality of bent portions extending from the inner periphery of the fixing portion along its axial direction, and the plurality of bent portions are arranged at intervals and extend into the frame; the bent portion of each of the first claw poles is located between the two bent portions of the corresponding second claw pole, and the bent portion of each of the second claw poles is located between the two bent portions of the corresponding first claw pole.

9. The stepping motor according to claim 8, characterized in that: The inner side of the skeleton in each of the windings is provided with a plurality of grooves that are recessed inwardly, and the shapes of the plurality of grooves respectively match the plurality of bending portions of the first claw pole and the plurality of bending portions of the second claw pole, and the plurality of bending portions of the first claw pole and the plurality of bending portions of the second claw pole are respectively accommodated and fixed in the corresponding grooves.

10. The stepper motor according to claim 1, characterized in that: Each of the first claw poles is integrally formed with the corresponding housing.

11. The stepper motor according to claim 1, characterized in that: The winding unit includes a plurality of windings arranged along the axial direction of the rotating shaft, the shells in the plurality of windings are fixedly connected in sequence, and the corresponding notches in the plurality of windings are connected to each other along the axial direction of the rotating shaft.

12. The stepper motor according to claim 11, characterized in that: The shell in each of the windings includes a first shell and a second shell which are hollow and overlapped with each other along the axial direction of the rotating shaft, and the notches are respectively arranged in the first shell and the second shell; the two outer windings also include a cover body which is fixed to the end of the first shell away from the second shell, and the first shell in the two outer windings is farther away from the other winding relative to the second shell, and the cover body is fixed to the rotating shaft through a bearing and forms a rotational connection with the rotating shaft, and the cover body is provided with an inwardly recessed notch corresponding to the position of the notch; the two first claw poles in each of the windings are respectively arranged at the end of the first shell and the second shell away from each other.

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