US-20260128656-A1 - STEP MOTOR

US20260128656A1US 20260128656 A1US20260128656 A1US 20260128656A1US-20260128656-A1

Abstract

Provided is a stepping motor including a rotary shaft, a magnet fixed to an outer peripheral side of the rotary shaft, and a winding unit sleeved on the rotary shaft and forming a rotatable connection with the rotary shaft. The winding unit includes at least one winding. Each winding is disposed apart from the magnet, and includes a shell sleeved on the rotary shaft, a skeleton fixed to the shell, two first claw poles fixed to two ends of the shell, two second claw poles fixed to a middle region of the skeleton, and two coils wound around the skeleton and disposed at intervals. Two opposite sides of the shell of each winding each is provided with a slot penetrating through the sidewall of the shell. The stepping motor can increase the effective volume of the whole magnetic circuit, and improve the torque performance by around 15%.

Inventors

Sensen Yang
Jinguo Wu
Junsheng Wang

Assignees

AAC MICROTECH (CHANGZHOU) CO., LTD.

Dates

Publication Date: 20260507
Application Date: 20250407

Claims (12)

1 . A step motor, comprising: a rotary shaft, a magnet fixed to an outer peripheral side of the rotary shaft, and a winding unit sleeved on the rotary shaft and forming a rotatable connection with the rotary shaft, the winding unit comprising at least one winding arranged along an axial direction of the rotary shaft, and each winding being disposed apart from the magnet; wherein each winding comprises a shell sleeved on the rotary shaft and forming a rotatable connection with the rotary shaft, a skeleton fixed to an inner side of the shell and disposed coaxially with the shell, two first claw poles respectively fixed to two ends of the shell, two second claw poles fixed to a middle region of the skeleton, and two coils respectively wound around an outer peripheral side of the skeleton and disposed at intervals; the shell has an annular shape and is formed by enclosing its sidewall, each of the second claw poles extends into the skeleton and forms a fixed connection with the skeleton, each of the first claw poles is disposed opposite to and fit with a corresponding one of the second claw poles, and each of the coils is located at an outer side of a corresponding one of the first claw poles and an outer side of a corresponding one of the second claw poles; and two opposite sides of the shell of each winding each is provided with a slot penetrating through the sidewall of the shell.
2 . The step motor as described in claim 1 , wherein the two second claw poles of each winding are each embedded into a corresponding skeleton, and are each integrally molded with the corresponding skeleton by insert injection molding.
3 . The step motor as described in claim 1 , further comprising a flexible circuit board fixed to the winding unit and forming an electrical connection with the winding unit, wherein the flexible circuit board is fixed to the skeleton of each winding, and the flexible circuit board is electrically connected to all the coils of each winding.
4 . The step motor as described in claim 3 , wherein the middle region of the skeleton of each winding is provided with an extension protruding and passing through the shell, wherein a side of the extension away from the skeleton is provided with four winding posts protruding at intervals, and the four winding posts are respectively inserted and fixed to the flexible circuit board; and two ends of each of the two coils of each winding are respectively wound around two of the four winding posts and form electrical connections with the flexible circuit board.
5 . The step motor as described in claim 4 , wherein the winding posts and the extension of each winding are integrally molded with the skeleton by injection molding.
6 . The step motor as described in claim 1 , wherein the magnet is a sintered magnet.
7 . The step motor as described in claim 6 , wherein the step motor includes a plurality of magnets, the plurality of magnets are disposed around the rotary shaft and fixed to the outer peripheral side of the rotary shaft, and the plurality of magnets are arranged at intervals.
8 . The step motor as described in claim 1 , wherein each of the first claw poles and each of the second claw poles each comprises an annular fixed portion and a plurality of bending portions extending and bent from an inner periphery of the fixed portion along an axial direction of the fixed portion, and the plurality of bending portions are provided at intervals and all extend into the skeleton; and the bending portions of each of the first claw poles are each located between two of the bending portions of a corresponding one of the second claw poles, and the bending portions of each of the second claw poles are each located between two of the bending portions of a corresponding one of the first claw poles.
9 . The step motor as described in claim 8 , wherein an inner side of the skeleton of each winding is provided with a plurality of grooves formed by recessing inward, the plurality of grooves respectively match the plurality of bending portions of each of the first claw poles and the plurality of bending portions of each of the second claw poles in shape, and the plurality of bending portions of each of the first claw poles and the plurality of bending portions of each of the second claw poles are each accommodated and fixed in a corresponding groove.
10 . The step motor as described in claim 1 , wherein each of the first claw poles is integrally molded with the shell corresponding to the first claw poles.
11 . The step motor as described in claim 1 , wherein the winding unit comprises a plurality of windings arranged along the axial direction of the rotary shaft, the shells of the plurality of windings are fixedly connected to one another in sequence, and the respective slots of the plurality of windings lead to each other along the axial direction of the rotary shaft.
12 . The step motor as described in claim 11 , wherein the shell of each winding comprises a first shell and a second shell that are hollow and mutually overlapped along the axial direction of the rotary shaft, and the slots are respectively disposed in the first shell and the second shell; each of two outer windings of the windings further comprises a cover body that covers and is fixed to one end of the first shell away from the second shell, in each of the two outer windings, the first shell is further away from another one of the windings than the second shell, the cover body is fixed to the rotary shaft through a bearing and forms a rotatable connection with the rotary shaft, and the cover body is provided with an inwardly recessed notch in a position of the cover body corresponding to the slots; and the two first claw poles of each winding are respectively disposed at an end of the first shell and an end of the second shell which are away from each other.

Description

TECHNICAL FIELD The present disclosure relates to the technical field of motors, and in particular, to a step motor applied to a foldable-screen mobile phone. BACKGROUND Step motors have been widely used in most technical fields, such as electromotor field, electric generator field, and folding-related field, due to their advantages of compact structure, high efficiency, energy conservation and consumption reduction and the like. In the folding-related field, as shown in FIG. 1, an automatic folding hinge 101 adopted by a foldable-screen mobile phone 100 needs to be realized by a step motor. To realize the lightness and thinness of the foldable-screen mobile phone 100, its thickness in the Z-axis direction needs to be further reduced, i.e., the arrangement space in the Z-axis direction needs to be reduced, whereas the arrangement space in the Y-axis direction is relatively loose and does not need to be further reduced. Under the condition that the arrangement space in the Z-axis direction is limited, to ensure that the automatic folding function of the foldable-screen mobile phone 100 is not affected, it is necessary to ensure that the step motor has a sufficiently large output torque. In the related art, a motor 200 mainly includes a shaft body 210, a magnet 220 fixed to an outer peripheral side of the shaft body 210, a winding structure sleeved on the shaft body 210 and forming a rotatable connection with the shaft body 210, and a flexible circuit board fixed to the winding structure and forming an electrical connection with the winding structure, as shown in conjunction with FIG. 2 and FIG. 3. The winding structure includes four coil assemblies 230. Each of the coil assemblies 230 includes a housing 2301 sleeved on the shaft body 210 and formed by enclosing its sidewall, a bracket 2302 fixed to an inner side of the housing 2301, a first claw pole structure 2303 fixed to the housing 2301 and extending into the bracket 2302, a second claw pole structure 2304 fixed to the bracket 2302 and disposed directly opposite to the first claw pole structure 2303, a coil structure 2305 fixed to an outer side of the bracket 2302, and winding posts 2306 fixed to the outer side of the bracket 2302. The outer housing 2301 forms the rotatable connection with the shaft body 210 through cover plates 2307 and bearing bodies 2308. To limit the position of the second claw pole structure 2304, a small slot 240 needs to be designed in a side surface of the housing 2301. To allow the winding posts 2306 to pass through, a large slot 250 needs to be designed in the side surface of the housing 2301. In conclusion, in the related art, the small slot 240 and the large slot 250 designed in the housing 2301 of the motor 200 each are to form an avoidance position. In the case that the size of the motor 200 in a single direction is limited, this design mode may cause the volumes of the magnet 220, the sidewall of the housing 2301, the first claw pole structure 2303, the second claw pole structure 2304, and the coil structure 2305 to be also limited by the size in the single direction, resulting in a smaller torque of the motor 200. Therefore, it is necessary to provide a new step motor to solve the above technical problem. SUMMARY An object of the present disclosure is to provide a new step motor to solve the problem in the related art that the design of the housing of the motor may result in a smaller torque. In order to achieve the above object, the present disclosure provides a step motor including: a rotary shaft, a magnet fixed to an outer peripheral side of the rotary shaft, and a winding unit sleeved on the rotary shaft and forming a rotatable connection with the rotary shaft, the winding unit including at least one winding arranged along an axial direction of the rotary shaft, and each winding being disposed apart from the magnet; where each winding includes a shell sleeved on the rotary shaft and forming a rotatable connection with the rotary shaft, a skeleton fixed to an inner side of the shell and disposed coaxially with the shell, two first claw poles respectively fixed to two ends of the shell, two second claw poles fixed to a middle region of the skeleton, and two coils respectively wound around an outer peripheral side of the skeleton and disposed at intervals; the shell has an annular shape and is formed by enclosing its sidewall, each of the second claw poles extends into the skeleton and forms a fixed connection with the skeleton, each of the first claw poles is disposed opposite to and fit with a corresponding one of the second claw poles, and each of the coils is located at an outer side of a corresponding one of the first claw poles and an outer side of a corresponding one of the second claw poles; and two opposite sides of the shell of each winding each is provided with a slot penetrating through the sidewall of the shell. As an improvement, the two second claw poles of each winding are each embedded into a correspond