Stepper motor and motor module

Abstract

The present invention provides a stepper motor and a motor module, wherein the stepper motor includes a housing, a rotating shaft rotatably connected to the housing, a magnetic steel fixed to the rotating shaft, and a winding assembly accommodated on the inner side of the housing, the winding assembly is spaced around the magnetic steel; the winding assembly includes a skeleton that is annular and coaxial with the housing, two claw poles arranged at relative intervals along the axial direction of the rotating shaft, and a coil wound on the skeleton; the skeleton includes a side wall on which the coil is wound, the side wall includes an arc portion with a first thickness and a first plane portion with a second thickness, the second thickness is less than the first thickness, and the first plane portion includes an outer surface that fits the coil, and the outer surface is a plane. The stepper motor in the present invention can not only solve the problem that the local wall thickness of the skeleton is reduced, which makes it difficult to form, but also cooperate with the corresponding design of the remaining structures to further reduce the thickness of the stepper motor.

Description

Technical Field

[0001] The present invention relates to the field of motor technology, and in particular to a stepping motor and a motor module. 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 smart devices.

[0003] In the related art, the stepper motor mainly includes a shell, a rotating shaft rotatably connected to the shell, a magnet fixed to the outer peripheral side of the rotating shaft, and a winding assembly sleeved on the rotating shaft and rotatably connected to the rotating shaft, and the winding assembly is spaced around the outer side of the magnet; the winding assembly includes a plastic frame fixed to the inner side of the shell, two claw poles arranged at relative intervals around the axial direction of the rotating shaft, and a coil wound around the outer peripheral side of the plastic frame.

[0004] The development direction of thin and light and high-performance application of smart devices requires stepper motors to provide higher torque with smaller thickness and volume. However, the plastic frame of the stepper motor in the related art is easily limited by the thickness of the molding wall, that is, the molding wall thickness of the plastic frame needs to be consistent, which will result in the thickness of the stepper motor cannot be further reduced. Therefore, it is necessary to provide a stepper motor and motor module with small thickness and good performance to solve the above technical problems. Summary of the invention

[0005] The purpose of the present invention is to provide a new stepper motor and a motor module to solve the problem in the related art that the frame of the stepper motor is limited by the thickness of the molding wall, thereby resulting in the thickness of the stepper motor cannot be further reduced.

[0006] In order to achieve the above-mentioned object, in a first aspect, the present invention provides a stepping motor, comprising a housing, a rotating shaft rotatably connected to the housing, a magnetic steel fixed to the rotating shaft, and a winding assembly accommodated and fixed to the inner side surface of the housing, wherein the winding assembly is spaced around the outer side of the magnetic steel;

[0007] The winding assembly includes a ring-shaped skeleton coaxially arranged with the shell, two claw poles relatively spaced apart along the axial direction of the rotating shaft, and a coil wound on the outer peripheral side of the skeleton, the two claw poles both extend into the skeleton and are relatively spaced apart from the magnetic steel, the skeleton includes a side wall around which the coil is wound, the side wall includes an arc portion with a first thickness and a first planar portion with a second thickness, the second thickness is less than the first thickness, the first planar portion includes an outer surface in contact with the coil, and the outer surface is a plane.

[0008] Preferably, the coil includes a first coil segment attached to the arc-shaped portion and a second coil segment attached to the first planar portion, the first coil segment is arc-shaped, and the second coil segment is flat-plate-shaped.

[0009] Preferably, the skeleton further includes a hollow area penetrating the first planar portion, and the thickness of the first planar portion gradually decreases from both ends connected to the arc-shaped portion toward a direction approaching the hollow area.

[0010] Preferably, the shell includes a second planar portion parallel to and opposite to the first planar portion; the claw pole includes a third planar portion parallel to and matching the second planar portion, and both the second planar portion and the third planar portion are flat.

[0011] Preferably, the skeleton also includes two annular surrounding portions formed by the side walls being bent and extended outward at opposite ends along the axial direction of the rotating shaft, an extension portion formed by one of the surrounding portions protruding away from one side of the side wall, and two winding poles formed by the extension portion protruding away from one side of the surrounding portions and extending and spaced from each other, the shell is provided with a through hole passing therethrough, the extension portion extends from the through hole to the outside of the shell, the surrounding portion includes a fourth planar portion parallel to and matching the second planar portion, the fourth planar portion is flat; the first planar portion is parallel to the extension direction of the winding poles, and the two ends of the coil are respectively wound around the two winding poles.

[0012] Preferably, the claw poles all include a fixing portion which is annular and fixed to the shell, and a plurality of pole claws formed by the inner periphery of the fixing portion being bent and extended along the axial direction of the rotating shaft, the plurality of pole claws are arranged at intervals and all extend into the frame and form a fixed connection with the frame, and the third planar portion is arranged on the fixing portion; the pole claw of one of the claw poles is located between the two pole claws of the other claw pole.

[0013] Preferably, the shell includes two cover plates fixed to the two ends of the rotating shaft through a rotating bearing and a main body portion which is fixedly connected with the two cover plates and is annular, the second planar portion is arranged on the main body portion, and the cover plate includes a fifth planar portion which is parallel to and matches the second planar portion, and the fifth planar portion is in the shape of a flat plate.

[0014] Preferably, the stepper motor comprises at least two winding assemblies, and the at least two winding assemblies are stacked in sequence along the axial direction of the rotating shaft.

[0015] Preferably, the skeleton includes two first planar portions, and the two first planar portions are arranged opposite to each other in a radial direction of the rotating shaft.

[0016] In a second aspect, the present invention provides a motor module, which includes the stepper motor as described above and a gear box fixed to one end of the rotating shaft and forming a rotational connection with the rotating shaft; the gear box includes a sixth planar portion parallel to and matching the second planar portion, and the sixth planar portion is flat.

[0017] Preferably, the gear box includes a hollow outer shell, a connecting bearing fixed to one end of the outer shell, a connecting portion fixed in the connecting bearing, a gear group accommodated in the outer shell and meshingly connected with the connecting portion, and a shaft meshingly connected with the gear group and extending outside the outer shell, the sixth planar portion is arranged at a side position of the outer shell corresponding to the second planar portion, and a preset distance is set between the gear group and the connecting bearing.

[0018] Preferably, the cross-section of the shell is circular and includes a first connecting section close to the rotating shaft and a second connecting section formed by extending from the first connecting section in a direction away from the rotating shaft, the outer diameter of the first connecting section is larger than the outer diameter of the first connecting section, the sixth planar portion is arranged at a side position of the first connecting section corresponding to the second planar portion, and the sixth planar portion and the outer side surface position corresponding to the second connecting section are in the same horizontal plane; the bearing is fixed to the first connecting section, the gear set is accommodated in the second connecting section, and the distance between the gear set and the first connecting section is the preset distance.

[0019] Compared with the related art, the stepper motor in the present invention designs the side wall of the skeleton into an arc-shaped portion with a first thickness and a first plane portion with a second thickness, and limits the second thickness to be less than the first thickness, and the first plane portion includes an outer surface that fits the coil, and the outer surface is a plane. In this way, the pressure of injection molding of the skeleton can be effectively reduced to break the situation where the local wall thickness of the skeleton is reduced and the molding difficulty is caused, thereby ensuring the injection molding of the skeleton. At the same time, the corresponding design of the remaining structures can be used to further reduce the thickness of the stepper motor, so as to achieve a significant reduction in the thickness of the stepper motor under the same torque, or increase its torque by 15-25% under the same thickness of the stepper motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] 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:

[0021] Figure 1 A schematic diagram of the three-dimensional structure of a stepping motor provided in the first embodiment of the present invention;

[0022] Figure 2 A partial structural exploded view of a stepping motor provided in Embodiment 1 of the present invention;

[0023] Figure 3 For along Figure 1 Sectional view along line AA;

[0024] Figure 4 For along Figure 1 Sectional view along the midline BB;

[0025] Figure 5 A schematic diagram of the three-dimensional structure of a motor module provided in Embodiment 2 of the present invention;

[0026] Figure 6 This is a partial structural exploded view of the motor module provided in the second embodiment of the present invention.

[0027] Among them: 100, stepper motor; 1, rotating shaft; 2, magnetic steel; 3, winding assembly; 31, skeleton; 311, side wall; 3111, arc portion; 3112, first plane portion; 31121, hollow area; 312, surrounding portion; 3121, fourth plane portion; 313, extension portion; 314, winding column; 32, claw pole; 321, fixing portion; 3211, third plane portion; 322, pole claw; 33, coil; 331, first coil segment; 332, second coil segment; 4, shell; 41, cover plate; 411, fifth plane portion; 42, rotating bearing; 43, main body; 431, second plane portion; 44, through hole.

[0028] 200, motor module; 5, gear box; 51, housing; 511, first connecting section; 5111, sixth plane portion; 512, second connecting section; 52, connecting bearing; 53, connecting portion; 54, gear set; 55, shaft. DETAILED DESCRIPTION

[0029] 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.

[0030] Embodiment 1

[0031] The embodiment of the present invention provides a stepping motor 100, Figures 1 to 3As shown, it includes a shell 4, a rotating shaft 1 rotatably connected to the shell 4, a magnetic steel 2 fixed to the rotating shaft 1, and a winding assembly 3 accommodated and fixed to the inner side surface of the shell 4, and the winding assembly 3 is spaced around the outer side of the magnetic steel 2.

[0032] The winding assembly 3 includes a ring-shaped frame 31 coaxially arranged with the housing 4, two claw poles 32 relatively spaced apart along the axial direction of the rotating shaft 1, and a coil 33 wound around the outer peripheral side of the frame 31. Both claw poles 32 extend into the frame 31 and are relatively spaced apart from the magnet 2.

[0033] The skeleton 31 includes a side wall 311 around which the coil is wound. The side wall 311 includes an arc portion 3111 with a first thickness and a first planar portion 3112 with a second thickness. The second thickness is smaller than the first thickness. The first planar portion 3112 includes an outer surface that fits the coil 33, and the outer surface is a plane.

[0034] The coil 33 includes a first coil segment 331 attached to the arc portion 3111 and a second coil segment 332 attached to the first plane portion 3112. The first coil segment 331 is arc-shaped, and the second coil segment 332 is flat. By designing the second coil segment 332 attached to the first plane portion 3112 of the coil 33 to be flat, the thickness of the stepping motor 100 can be further reduced by cooperating with the corresponding design of the remaining structures.

[0035] The skeleton 31 also includes a hollow area 31121 that passes through the first plane portion 3112. The thickness of the first plane portion 3112 gradually decreases from the two ends connected to the arc portion 3111 to the direction close to the hollow area 31121. Preferably, the hollow area 31121 is set in the middle of the first plane portion 3112, that is, the plastic in the thinnest area in the center of the first plane portion 3112 is removed. This design will prevent the skeleton 31 from having an extreme thin wall, or allow the skeleton 31 to be not filled during molding, resulting in similar cavities, thereby ensuring the feasibility of molding the skeleton 31.

[0036] The other areas of the skeleton 31 except the first planar portion 3112 are designed according to the optimal wall thickness, that is, the arc portion 3111 is designed according to the optimal wall thickness. Such a design is equivalent to designing according to the optimal wall thickness of the skeleton 31, that is, a thinner wall thickness that is formable and strong enough to ensure the compactness of the skeleton 31.

[0037] The housing 4 includes a second plane portion 431 which is parallel to and opposite to the first plane portion 3112, and the second plane portion 431 is in the shape of a plate. This design can be combined with the corresponding design of other structures to further reduce the thickness of the stepper motor 100.

[0038] The housing 4 includes two cover plates 41 fixed to both ends of the rotating shaft 1 through a rotating bearing 42 and a ring-shaped body portion 43 fixedly connected to the two cover plates 41, and the second plane portion 431 is provided on the body portion 43. This design can realize the rotating connection between the housing 4 and the rotating shaft 1.

[0039] The cover plate 41 includes a fifth plane portion 411 which is parallel to and matches the second plane portion 431, and the fifth plane portion 411 is in the shape of a flat plate. This design can be coordinated with the corresponding design of other structures to further reduce the thickness of the stepper motor 100.

[0040] The skeleton 31 also includes two annular surrounding portions 312 formed by bending and extending outward at opposite ends of the side wall 311 along the axial direction of the rotating shaft 1, an extension portion 313 formed by protruding from one of the surrounding portions 312 away from the side wall 311, and two winding poles 314 formed by protruding and extending from the extension portion 313 away from the side of the surrounding portion 312 and spaced from each other. The shell 4 is provided with a through hole 44 passing through it, and the extension portion 313 extends from the through hole 44 to the outside of the shell 4. The surrounding portion 312 includes a fourth planar portion 3121 parallel to and matching the second planar portion 431, and the fourth planar portion 3121 is flat; the first planar portion 3112 is parallel to the extension direction of the winding pole 314, and the two ends of the coil 33 are respectively wound around the two winding poles 314. The design of the winding post 314 can facilitate the winding of the two ends of the coil 33 , and the corresponding fourth plane portion 3121 is provided on the surrounding portion 312 , so that the thickness of the stepping motor 100 can be further reduced in coordination with the corresponding other structures.

[0041] The claw pole 32 includes a third plane portion 3211 parallel to and matching the second plane portion 431, and the third plane portion 3211 is in the shape of a plate; wherein the housing 4 is designed according to a safety gap reserved with the coil 33. Such a design enables the claw pole 32 to adapt to the first plane portion 3112 and the second coil segment 332 of the coil 33, so that the stepping motor 100 is configured in a minimum space with equal gaps, thereby ensuring the compactness of the stepping motor 100, which is equivalent to further reducing the thickness of the stepping motor 100.

[0042] The claw pole 32 includes a fixing portion 321 which is annular and fixed to the housing 4, and a plurality of pole claws 322 formed by the inner circumference of the fixing portion 321 being bent and extended along the axial direction of the rotating shaft 1. The plurality of pole claws 322 are arranged at intervals and all extend into the frame 31 and form a fixed connection with the surrounding portion 312 of the frame 31. The third planar portion 3211 is arranged on the fixing portion 321; the pole claw 322 of one claw pole 32 is located between the two pole claws 322 of the other claw pole 32.

[0043] The skeleton 31 includes two first planar portions 3112, and the two first planar portions 3112 are arranged opposite to each other along the radial direction of the rotating shaft 1; accordingly, the second planar portion 431, the third planar portion 3211, the fourth planar portion 3121 and the fifth planar portion 411 all include two first planar portions 3112, the second planar portion 431, the third planar portion 3211, the fourth planar portion 3121 and the fifth planar portion 411 on the same side are all in the same horizontal plane.

[0044] The winding assembly 3 may be designed as one or more. When the winding assembly 3 is designed as more than one, the multiple winding assemblies 3 are stacked in sequence along the axial direction of the rotating shaft 1 .

[0045] When the winding assembly 3 and the main body 43 are both one, the two ends of the main body 43 are respectively fixedly connected with the two cover plates 41, which is equivalent to the rotating shaft 1 being rotatably connected with the housing 4 through the cover plates 41 and the rotating bearing 42. At the same time, the two claw poles 32 in the winding assembly 3 are respectively fixed to the two ends of the main body 43.

[0046] When there are multiple winding assemblies 3, the number of main bodies 43 is the same as the number of winding assemblies 3, and the multiple main bodies 43 are fixedly connected in sequence. The ends of the two outermost main bodies 43 that are away from each other are fixedly connected with the two cover plates 41 respectively, which is equivalent to the rotating shaft 1 being rotatably connected with the housing 4 through the cover plate 41 and the rotating bearing 42. At the same time, the two claw poles 32 in each winding assembly 3 are respectively fixed to the two ends of a corresponding main body 43; in addition, the first plane portion 3112, the second plane portion 431, the third plane portion 3211, the fourth plane portion 3121 and the fifth plane portion 411 in each winding assembly 3 are all in the same horizontal plane. If there are two first plane portions 3112, the second plane portion 431, the third plane portion 3211, the fourth plane portion 3121 and the fifth plane portion 411, the first plane portion 3112, the second plane portion 431, the third plane portion 3211, the fourth plane portion 3121 and the fifth plane portion 411 on the same side are in the same horizontal plane.

[0047] In this embodiment, the winding assembly 3 includes two winding assemblies 3 which are sequentially stacked along the axial direction of the rotating shaft 1 , and correspondingly, the main body 43 of the housing 4 also includes two winding assemblies 3 .

[0048] Combination Figure 4As shown, the central wall thickness of the first plane portion 3112 of the skeleton 31 is set to B, the wall thickness of the remaining positions of the skeleton 31 except the first plane portion 3112 is set to A, and the overall thickness dimension of the stepper motor 100 is set to H. At this time, the overall thickness dimension of the stepper motor 100 is reduced by 2* (AB). Assuming A is 0.15mm and B is 0.05mm, for a conventional stepper motor with an original width (or the diameter dimension of the entire outer side) of 5.2mm and an original length (including the extension part and the winding part) of 8mm, the design method of the stepper motor 100 in this embodiment can reduce the overall thickness dimension of the conventional stepper motor by 2* (0.15-0.05) = 0.2mm, and its torque can be increased by 15-25% accordingly. The diameter dimension of the entire outer side of the stepper motor 100 is set to M, then M=H+2* (AB). In addition, the situation of M≥H+2* (AB) is also applicable to the design method of the stepper motor 100 in this embodiment.

[0049] Compared with the related art, the stepper motor 100 in the present invention designs the side wall 311 of the skeleton 31 into an arc portion 3111 with a first thickness and a first plane portion 3112 with a second thickness, and limits the second thickness to be less than the first thickness, and the first plane portion 3112 includes an outer surface that fits with the coil 33, and the outer surface is a plane. In this way, the pressure of injection molding of the skeleton 31 can be effectively reduced to break the situation where the local wall thickness of the skeleton 31 is reduced and the molding is difficult, thereby ensuring the injection molding of the skeleton 31. At the same time, the corresponding design of the remaining structures can be used to further reduce the thickness of the stepper motor 100, so as to achieve a significant reduction in the thickness of the stepper motor 100 under the condition of the same torque, or to increase its torque by 15-25% under the condition of the same thickness of the stepper motor 100.

[0050] Embodiment 2

[0051] The embodiment of the present invention provides a motor module 200, combined with Figure 5 and Figure 6 As shown, it includes the stepper motor 100 in the first embodiment and a gear box 5 fixed to one end of the rotating shaft 1 and rotatingly connected with the rotating shaft 1; the gear box 5 includes a sixth plane portion 5111 parallel to and matching the second plane portion 431, and the sixth plane portion 5111 is in a flat plate shape. By introducing the gear box 5 and designing the sixth plane portion 5111, the structure of the gear box 5 can be matched with the first plane portion 3112, the second plane portion 431, the third plane portion 3211, the fourth plane portion 3121 and the fifth plane portion 411, so that the stepper motor 100 can achieve a higher torque gain under the same width size.

[0052] The gearbox 5 includes a hollow housing 51, a connecting bearing 52 fixed to one end of the housing 51, a connecting portion 53 fixed in the connecting bearing 52, a gear set 54 received in the housing 51 and meshingly connected with the connecting portion 53, and a shaft 55 meshingly connected with the gear set 54 and extending outside the housing 51, a sixth plane portion 5111 is provided at a side position of the housing 51 corresponding to the second plane portion 431, and a preset distance (safety distance) is provided between the gear set 54 and the connecting bearing 52. Such a step design can make the gearbox 5 more compatible with the first plane portion 3112, the second plane portion 431, the third plane portion 3211, the fourth plane portion 3121 and the fifth plane portion 411, and can also ensure the manufacturability of its parts and the process technology of the finished product.

[0053] The cross section of the housing 51 is circular and includes a first connecting section 511 close to the rotating shaft 1 and a second connecting section 512 extending from the first connecting section 511 in a direction away from the rotating shaft 1. The outer diameter of the first connecting section 511 is greater than the outer diameter of the first connecting section 511. The sixth plane portion 5111 is provided at the side position of the first connecting section 511 corresponding to the second plane portion 431. The sixth plane portion 5111 and the outer side position corresponding to the second connecting section 512 are in the same horizontal plane. The bearing is fixed to the first connecting section 511, and the gear set 54 is accommodated in the second connecting section 512. The distance between the gear set 54 and the first connecting section 511 is a preset distance. This design can make the length of the sixth plane portion 5111 meet the welding alignment requirements, and keep the position of the gear set 54 still at a certain safety distance, thereby ensuring the best molding roundness of the second connecting section 512. In addition, the spacing between the two sixth plane portions 5111 is equal to the outer diameter of the second connecting section 512, and can also ensure that the gear box 5 has the thinnest thickness.

[0054] When the second planar portion 431 includes two, the sixth planar portion 5111 also includes two, the spacing between the two sixth planar portions 5111 is equal to the outer diameter of the second connecting section 512, and the first planar portion 3112, the second planar portion 431, the third planar portion 3211, the fourth planar portion 3121, the fifth planar portion 411 and the sixth planar portion 5111 on the same side are all in the same horizontal plane.

[0055] Since the motor module 200 in this embodiment includes the stepper motor 100 in the first embodiment, the motor module 200 in this embodiment can also achieve the technical effect achieved by the stepper motor 100 in the first embodiment, which will not be elaborated here.

[0056] 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 stepper motor, comprising a housing, a rotating shaft rotatably connected to the housing, a magnetic steel fixed to the rotating shaft, and a winding assembly received and fixed to the inner side of the housing, wherein a spacer ring of the winding assembly is arranged on the outer side of the magnetic steel; The winding assembly includes a ring-shaped frame coaxially arranged with the housing, two claw poles relatively spaced apart along the axial direction of the rotating shaft, and a coil wound around the outer circumference of the frame, wherein the two claw poles extend into the frame and are relatively spaced apart from the magnetic steel; characterized in that: The skeleton includes a side wall around which the coil is wound, the side wall includes an arc portion with a first thickness and a first plane portion with a second thickness, the second thickness is less than the first thickness, the first plane portion includes an outer surface that fits the coil, and the outer surface is a plane; The frame further includes a hollow area penetrating the first planar portion, and the thickness of the first planar portion gradually decreases from two ends connected to the arc-shaped portion toward the direction close to the hollow area.

2. The stepper motor according to claim 1, characterized in that: The coil includes a first coil segment attached to the arc portion and a second coil segment attached to the first planar portion. The first coil segment is arc-shaped, and the second coil segment is flat-plate-shaped.

3. The stepper motor according to claim 1, characterized in that: The housing includes a second planar portion which is parallel to and opposite to the first planar portion; the claw pole includes a third planar portion which is parallel to and matches the second planar portion, and both the second planar portion and the third planar portion are in the shape of a flat plate.

4. The stepping motor according to claim 3, characterized in that: The skeleton also includes two annular surrounding parts formed by the side wall being bent and extended outward at opposite ends along the axial direction of the rotating shaft, an extension part formed by one of the surrounding parts protruding away from the side wall, and two winding poles formed by the extension part protruding away from the side of the surrounding part and extending and spaced from each other. The shell is provided with a through hole passing through it, and the extension part extends from the through hole to the outside of the shell. The surrounding part includes a fourth planar part parallel to and matching with the second planar part, and the fourth planar part is flat. The first planar part is parallel to the extension direction of the winding pole, and the two ends of the coil are respectively wound around the two winding poles.

5. The stepping motor according to claim 3, characterized in that: The claw poles all include a fixing portion that is annular and fixed to the shell, and a plurality of pole claws formed by the inner circumference of the fixing portion being bent and extended along the axial direction of the rotating shaft. The plurality of pole claws are arranged at intervals and all extend into the frame and are fixedly connected to the frame. The third planar portion is arranged on the fixing portion; the pole claw of one of the claw poles is located between the two pole claws of the other claw pole.

6. The stepping motor according to claim 3, characterized in that: The shell includes two cover plates fixed to the two ends of the rotating shaft through a rotating bearing and a main body portion fixedly connected to the two cover plates and in an annular shape, the second planar portion is arranged on the main body portion, and the cover plate includes a fifth planar portion parallel to and matching the second planar portion, and the fifth planar portion is in the shape of a flat plate.

7. The stepper motor according to claim 1, characterized in that: The stepper motor comprises at least two winding assemblies, and the at least two winding assemblies are stacked in sequence along the axial direction of the rotating shaft.

8. The stepper motor according to claim 1, characterized in that: The skeleton includes two first planar portions, and the two first planar portions are arranged opposite to each other along the radial direction of the rotating shaft.

9. A motor module, characterized in that: The motor module includes the stepper motor as described in claim 3 and a gear box fixed to one end of the rotating shaft and rotatingly connected with the rotating shaft; the gear box includes a sixth planar portion parallel to and matching the second planar portion, and the sixth planar portion is flat.

10. The motor module according to claim 9, characterized in that: The gear box includes a hollow shell, a connecting bearing fixed to one end of the shell, a connecting portion fixed in the connecting bearing, a gear set accommodated in the shell and meshingly connected to the connecting portion, and a shaft meshingly connected to the gear set and extending outside the shell, the sixth planar portion is arranged at a side position of the shell corresponding to the second planar portion, and a preset distance is arranged between the gear set and the connecting bearing.

11. The motor module according to claim 10, characterized in that: The cross-section of the housing is circular and includes a first connecting section close to the rotating shaft and a second connecting section formed by extending from the first connecting section in a direction away from the rotating shaft, the outer diameter of the first connecting section is larger than the outer diameter of the first connecting section, the sixth planar portion is arranged at a side position of the first connecting section corresponding to the second planar portion, and the sixth planar portion and the outer side surface position corresponding to the second connecting section are in the same horizontal plane; the bearing is fixed to the first connecting section, the gear set is accommodated in the second connecting section, and the distance between the gear set and the first connecting section is the preset distance.

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