Stepper motor
By fixing the stator assembly to the housing in the stepper motor and rotating the rotor assembly to the housing, and setting springs on the rotor assembly, the problems of transmission accuracy and noise are solved, and smaller backlash and better shock absorption are achieved. It has the advantages of small size and low cost.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- AAC MICROTECH (CHANGZHOU) CO LTD
- Filing Date
- 2024-11-06
- Publication Date
- 2026-05-15
AI Technical Summary
Existing stepper motors are prone to reduced transmission accuracy and noise under axial force, and the existing single-arm spring structure is prone to failure, has high cost, and poor design flexibility.
The stator assembly is fixed inside the housing, and the rotor assembly is rotatably connected to the housing. The stator assembly is arranged around the rotor assembly. The rotor assembly includes a permanent magnet and a rotating shaft. The spring is fixed to the first end cover. The spring has a limiting part, an annular fixing part, and a spring arm. The spring arm achieves a smaller backlash difference and better shock absorption and noise reduction capabilities.
It improves transmission accuracy, reduces noise, reduces motor size and cost, and at the same time improves reliability and design flexibility.
Smart Images
Figure CN2024130215_15052026_PF_FP_ABST
Abstract
Description
Stepper motor Technical Field
[0001] This utility model relates to the field of motor technology, and in particular to a stepper motor. Background Technology
[0002] Stepper motors are widely used in electric motors and generators due to their compact structure, high power density, high efficiency, and significant energy-saving benefits. In recent years, the industrial sector has seen an increasingly urgent demand for equipment that directly drives loads using stepper motors. The widespread application of these stepper motor direct-drive devices will generate immeasurable energy-saving benefits. Technical issues
[0003] In related technologies, most existing stepper motors include a housing, a rotor, a stator wound at intervals around the rotor, and a gearbox. The stator and rotor drive each other to achieve motor rotation, and the output shaft of the motor drives the gearbox for power transmission. The stator includes windings fixed to the outer periphery of the housing, and the rotor generally includes a shaft and magnets fixed to the outer periphery of the shaft. The magnets and windings drive each other to achieve motor rotation. However, in existing gearbox structures, when the motor is subjected to axial force, the axial movement of the motor shaft causes a significant decrease in transmission accuracy (accumulated during commutation), and the shaft end moves rapidly under force at startup, impacting the fixed component and generating noise. To reduce noise, a stamped single-arm spring is installed on one side of the housing, abutting the end of the shaft and fixed to the outer side of the housing. However, under long-term stress, this single-arm spring is prone to failure or weld peeling near the root, and the bending process results in complex structural features, high production costs, easy deformation during turnover, unilateral stress during use, high thickness requirements, poor design flexibility, and insufficient reliability.
[0004] Therefore, it is necessary to provide a new stepper motor to solve the above-mentioned technical problems. Technical solutions
[0005] The purpose of this invention is to provide a stepper motor with higher transmission accuracy, smaller backlash, better shock absorption and noise reduction capabilities, and smaller size and lower cost.
[0006] To achieve the above objectives, this utility model provides a stepper motor, comprising a housing, a stator assembly fixed to the inner circumference of the housing, a rotor assembly supported on the housing and rotatably connected to the housing, and a gearbox assembly drively connected to the output end of the rotor assembly. The stator assembly is arranged around the rotor assembly and spaced apart from the rotor assembly. The housing includes an outer shell and a first end cover and a second end cover respectively fixed to both ends of the outer shell. The gearbox assembly is fixed to the side of the second end cover away from the outer shell. The rotor assembly includes a rotating shaft rotatably connected to the first end cover and the second end cover respectively, and a permanent magnet sleeved and fixed to the rotating shaft. The outer circumference of the permanent magnet is spaced apart from the stator assembly. The present invention is characterized in that...
[0007] The stepper motor further includes a spring sheet with a flat plate structure and fixed to the first end cover. The spring sheet includes a limiting part abutting against the end of the rotating shaft away from the gearbox assembly, a ring-shaped fixing part surrounding the limiting part, and at least two spring arms connecting the limiting part and the fixing part; the fixing part is fixed to the first end cover.
[0008] Preferably, the limiting part has a circular structure and is located at the center of the fixing part; the elastic arm includes three elastic arms, which are arranged symmetrically about the center of the limiting part.
[0009] Preferably, the width of the spring arm gradually decreases from its two ends toward the middle.
[0010] Preferably, the spring arm is arc-shaped.
[0011] Preferably, the stepper motor further includes a first bearing and a second bearing disposed opposite to each other. The inner circumferential side of the first bearing is sleeved and fixed to the end of the rotating shaft away from the gearbox assembly, and the outer circumferential side of the first bearing is inserted and fixed to the first end cover. The side of the first bearing away from the permanent magnet abuts against the limiting part.
[0012] The inner circumferential side of the second bearing is sleeved and fixed to one end of the rotating shaft near the gearbox assembly, and the outer circumferential side of the second bearing is inserted and fixed to the second end cover. The end of the gearbox assembly near the housing is sleeved with the second bearing.
[0013] Preferably, the housing further includes a claw pole inserted and fixed to the outer shell, the claw pole and the outer shell together forming a mounting position; the stator assembly is sleeved and fixed to the outer shell and located within the mounting position; the stepper motor further includes a frame fixed to the housing, the frame including a ring-shaped frame body and a connecting portion extending from the frame body along an axial direction perpendicular to the rotating shaft; the frame body fixes the outer shell and is located within the mounting position, and the stator assembly is sleeved and fixed to the outer periphery of the frame.
[0014] Preferably, the stepper motor further includes a circuit board assembly, which is fixed to the end of the connection portion away from the housing.
[0015] Preferably, the stepper motor further includes a first pad and a second pad, the first pad and the second pad being respectively attached and fixed to opposite ends of the permanent magnet, and the first pad being spaced apart from the first end cap, and the second pad being spaced apart from the second end cap.
[0016] Preferably, the rotating shaft includes a rotating shaft body that is rotatably connected to the first end cover and the second end cover, a rotating shaft extension that extends from the rotating shaft body into the gearbox assembly, a limiting platform formed by the radial inward recess of the outer peripheral side of the rotating shaft extension, and a screw fixed to the limiting platform.
[0017] The gearbox assembly includes a housing that fixes the second end cover, a rotating shaft disposed on the housing and forming a rotatable connection, and a gear sleeved and fixed to the rotating shaft; the rotating shaft is arranged perpendicular to the rotating shaft, and the gear is threadedly connected to the screw.
[0018] Preferably, the stepper motor further includes a vibration damping block, which is fixed inside the housing, and the end of the shaft extension away from the shaft body abuts against the vibration damping block. Beneficial effects
[0019] Compared with the prior art, in the stepper motor of this utility model, the stator assembly is fixed inside the housing, and the rotor assembly is rotatably connected to the housing. The stator assembly is arranged around the rotor assembly and spaced apart from the rotor assembly. The magnetic field generated by the stator assembly and the rotor assembly drives the gearbox assembly to drive the transmission. The stator assembly is sleeved and fixed to the housing and located in the mounting position. The gearbox assembly is fixed to the side of the second end cover away from the housing. The rotor assembly is rotatably connected to the first end cover and the second end cover respectively. The rotor assembly includes a rotating shaft rotatably connected to the first end cover and the second end cover respectively, and a gearbox assembly sleeved and fixed to the housing. The permanent magnet of the rotating shaft is spaced apart from the stator assembly on its outer periphery. The stepper motor also includes a spring sheet with a flat plate structure and fixed to the first end cover. The spring sheet includes a limiting part that abuts against the end of the rotating shaft away from the gearbox assembly, a ring-shaped fixing part that surrounds the limiting part, and at least two spring arms that connect the limiting part and the fixing part. The fixing part is fixed to the first end cover. By abutting the limiting part of the spring sheet against the rotating shaft and fixing the fixing part to the first end cover, smaller backlash and better shock absorption and noise reduction capabilities are achieved through the spring arms. It also has advantages such as small size and low cost, and has strong potential for widespread application. Attached Figure Description
[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:
[0021] Figure 1 is a three-dimensional structural diagram of the stepper motor provided in an embodiment of the present invention;
[0022] Figure 2 is an exploded three-dimensional view of the stepper motor provided in the embodiment of this utility model;
[0023] Figure 3 is a cross-sectional view along line AA in Figure 1;
[0024] Figure 4 is a schematic diagram of the structure of the spring sheet provided in the embodiment of this utility model.
[0025] Among them, 100 is a stepper motor, 1 is a housing, 11 is an outer shell, 12 is a first end cover, 13 is a second end cover, 14 is a claw pole, 15 is a mounting position, 2 is a stator assembly, 3 is a rotor assembly, 31 is a permanent magnet, 32 is a rotating shaft, 321 is a rotating shaft body, 322 is a limiting platform, 323 is a screw, 324 is a rotating shaft extension, 4 is a gearbox assembly, 41 is a housing, 42 is a rotating shaft, 43 is a gear, 5 is a spring, 51 is a limiting part, 52 is a spring arm, 53 is a fixing part, 6 is a first bearing, 7 is a second bearing, 8 is a frame, 81 is a frame body, 82 is a connecting part, 9 is a circuit board assembly, 10 is a first gasket, 20 is a second gasket, and 30 is a vibration damping block. Embodiments of the present invention
[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.
[0027] Referring to Figures 1 to 4, this embodiment of the present invention provides a stepper motor 100, which includes a housing 1, a stator assembly 2 fixed to the inner circumference of the housing 1, a rotor assembly 3 supported on the housing 1 and rotatably connected to the housing 1, and a gearbox assembly 4 drively connected to the output end of the rotor assembly 3. The stator assembly 2 is arranged around the rotor assembly 3 and spaced apart from the rotor assembly 3. The housing 1 includes an outer shell 11 and a first end cover 12 and a second end cover 13 respectively fixed to both ends of the outer shell 11. The stator assembly 2 is sleeved and fixed to the outer shell 11 and located within the mounting position 15. The gearbox assembly 4 is fixed to the side of the second end cover 13 away from the outer shell 11. The rotor assembly 3 is rotatably connected to the first end cover 12 and the second end cover 13 respectively. The housing 1 is used to install and fix the first end cover 12 and the second end cover 13.
[0028] In this embodiment, the stator assembly 2 is a coil winding, which is arranged around the rotor assembly 3. Optionally, there can be at least two stator assemblies 2, which are arranged side by side along the axial direction of the rotating shaft 32 assembly.
[0029] The rotor assembly 3 includes a rotating shaft 32 rotatably connected to the first end cover 12 and the second end cover 13, and a permanent magnet 31 sleeved and fixed to the rotating shaft 32. The outer periphery of the permanent magnet 31 is spaced apart from the stator assembly 2. The rotating shaft 32 is driven to rotate by the magnetic field generated by the permanent magnet 31 and the stator assembly 2, thereby driving the gearbox assembly 4 to move.
[0030] The stepper motor 100 also includes a flat spring piece 5 fixed to the first end cover 12. The spring piece 5 includes a limiting portion 51 abutting against the end of the rotating shaft 32 away from the gearbox assembly 4, a ring-shaped fixing portion 53 surrounding the limiting portion 51, and at least two spring arms 52 connecting the limiting portion 51 and the fixing portion; the fixing portion 53 is fixed to the first end cover 12. By having the limiting portion 51 of the spring piece 5 abut against the rotating shaft 32 and the fixing portion 53 fixed to the first end cover 12, and using the spring arms 52, a smaller backlash difference and better shock absorption and noise reduction capabilities are achieved. It also has advantages such as small size and low cost, making it highly applicable. Furthermore, the introduction of the planar spring piece 5 effectively eliminates the gap in the motor's rotor assembly 3 and the accumulated errors of parts, ensuring that the system maintains high transmission accuracy and low noise performance. Simultaneously, the spring piece 5 provides shock absorption during drops, improving the reliability of the mechanism. It is subjected to stress throughout the entire circumference during use, resulting in a low risk of failure; it also offers high design flexibility, allowing for reduced thickness and smaller volume.
[0031] In this embodiment, the fixing part 53 is fixed to the first end cap 12 by welding or other processes.
[0032] In this embodiment, the limiting part 51 has a circular structure and is located at the center of the fixing part 53; the elastic arm 52 includes three, and the three elastic arms 52 are arranged symmetrically about the center of the limiting part 51.
[0033] Preferably, the device has two or more spring arms 52, with a recommended number n≥3. In this embodiment, there are three spring arms, but the actual number is not limited. The two ends of the spring arms 52 are respectively connected to the inner circular limiting part 51 and the outer ring-shaped fixing part 53, and are arranged symmetrically around the center of the limiting part 51 to ensure symmetrical force distribution on the mechanism and to provide better stability and reliability.
[0034] In this embodiment, the width of the spring arm 52 gradually decreases from both ends toward the middle, ensuring better stress performance.
[0035] In this embodiment, the spring arm 52 is arc-shaped. The arc-shaped structure (connecting rib structure) is generally designed with a gradually narrowing width from the end to the middle to ensure better stress performance. The arc-shaped design provides a certain degree of axial preload, which is recommended to be greater than the axial force exerted on the shaft 32 by the gear 43 to the left (away from the reduction gearbox assembly 4) under transmission load, ensuring the system remains stable at a high transmission accuracy.
[0036] In this embodiment, the stepper motor 100 further includes a first bearing 6 and a second bearing 7 disposed opposite to each other. The inner circumference of the first bearing 6 is sleeved and fixed to the end of the rotating shaft 32 away from the gearbox assembly 4, and the outer circumference of the first bearing 6 is inserted and fixed to the first end cover 12. The side of the first bearing 6 away from the permanent magnet 31 abuts against the spring arm 52. By abutting the end of the spring arm 52 against the end of the first bearing 6, better torque output of the motor can be ensured, but its application scenarios are not limited. For example, if it is set to abut against the end of the rotating shaft 32, it is still within the scope of patent protection.
[0037] The inner circumference of the second bearing 7 is sleeved and fixed to one end of the rotating shaft 32 near the gearbox assembly 4, and the outer circumference of the second bearing 7 is inserted and fixed to the second end cover 13. The end of the gearbox assembly 4 near the housing 1 is sleeved with the second bearing 7. By sleeved the first bearing 6 and the second bearing 7 at both ends of the rotating shaft 32, the friction of the rotating shaft 32 is small during rotation, the rotational power loss is low, and the output accuracy of the motor is high.
[0038] In this embodiment, the housing 1 further includes claw poles 14 inserted and fixed to the outer shell 11, the claw poles 14 and the outer shell 11 together forming a mounting position 15; the stator assembly 2 is sleeved and fixed to the outer shell 11 and located within the mounting position 15; the stepper motor 100 further includes a frame 8 fixed to the housing 1, the frame 8 including a ring-shaped frame body 81 and a connecting portion 82 extending from the frame body 81 along an axial direction perpendicular to the rotating shaft 32; the frame body 81 fixes the outer shell 11 and is located within the mounting position 15, and the stator assembly 2 is sleeved and fixed to the outer periphery of the frame 8. The frame body 81 is used to install and fix the stator assembly 2, so that the stator assembly 2 is highly stable during the driving process of the rotor assembly 3. The mounting position 15 is formed by the mutual insertion of the housing 1 and the claw poles 14, which facilitates the surrounding installation of the stator assembly 2.
[0039] In this embodiment, the stepper motor 100 further includes a circuit board assembly 9, which is fixed to the end of the connecting portion 82 away from the housing 11. The circuit board assembly 9 provides power to the stator assembly 2, enabling the stator assembly 2 to generate a magnetic field, facilitating mutual driving with the rotor assembly 3 and driving the rotating shaft 32 to rotate.
[0040] In this embodiment, the stepper motor 100 further includes a first pad 10 and a second pad 20. The first pad 10 and the second pad 20 are respectively attached and fixed to the opposite ends of the permanent magnet 31, with the first pad 10 spaced apart from the first end cap 12 and the second pad 20 spaced apart from the second end cap 13. This improves the fixing effect of the permanent magnet 31.
[0041] In this embodiment, the rotating shaft 32 includes a rotating shaft body 321 that is rotatably connected to the first end cover 12 and the second end cover 13, a rotating shaft extension 324 extending from the rotating shaft body 321 into the gearbox assembly 4, a limiting platform 322 formed by the radial inward recess of the outer peripheral side of the rotating shaft extension 324, and a screw 323 sleeved and fixed to the limiting platform 322.
[0042] The gearbox assembly 4 includes a housing 41 that fixes the second end cover 13, a rotating shaft 42 disposed on the housing 41 and rotatably connected thereto, and a gear 43 sleeved and fixed to the rotating shaft 42. The rotating shaft 42 is perpendicular to the rotating shaft 32, and the gear 43 is threadedly connected to the screw 323. The rotation of the rotating shaft 32 drives the screw 323 to rotate, which in turn drives the gear 43 to rotate, thereby achieving the function of a speed reducer.
[0043] In this embodiment, the stepper motor 100 further includes a vibration damping block 30, which is fixed inside the housing 41. The end of the shaft extension 324 away from the shaft body 321 abuts against the vibration damping block 30. During a drop or impact, the shaft 32 moves instantaneously away from the gearbox assembly 4, and the deformation of the spring 5 provides shock absorption and buffering, ensuring the reliability of the gear 43 end structure. The design and optimization of the spring arm 52 ensure that it is within the optimal elastic deformation range.
[0044] In this embodiment, the vibration damping block 30 is made of silicone material, which has high structural strength and good vibration damping effect.
[0045] Compared with the prior art, in the stepper motor of this utility model, the stator assembly is fixed inside the housing, and the rotor assembly is rotatably connected to the housing. The stator assembly is arranged around the rotor assembly and spaced apart from the rotor assembly. The magnetic field generated by the stator assembly and the rotor assembly drives the gearbox assembly to drive the transmission. The stator assembly is sleeved and fixed to the housing and located in the mounting position. The gearbox assembly is fixed to the side of the second end cover away from the housing. The rotor assembly is rotatably connected to the first end cover and the second end cover respectively. The rotor assembly includes a rotating shaft rotatably connected to the first end cover and the second end cover respectively, and a gearbox assembly sleeved and fixed to the housing. The permanent magnet of the rotating shaft is spaced apart from the stator assembly on its outer periphery. The stepper motor also includes a spring sheet with a flat plate structure and fixed to the first end cover. The spring sheet includes a limiting part that abuts against the end of the rotating shaft away from the gearbox assembly, a ring-shaped fixing part that surrounds the limiting part, and at least two spring arms that connect the limiting part and the fixing part. The fixing part is fixed to the first end cover. By abutting the limiting part of the spring sheet against the rotating shaft and fixing the fixing part to the first end cover, smaller backlash and better shock absorption and noise reduction capabilities are achieved through the spring arms. It also has advantages such as small size and low cost, and has strong potential for widespread application.
[0046] The above description is merely an embodiment of this utility model. It should be noted that those skilled in the art can make improvements without departing from the inventive concept of this utility model, but these improvements all fall within the protection scope of this utility model.
Claims
1. A stepper motor, comprising a housing, a stator assembly fixed to the inner periphery of the housing, a rotor assembly supported on the housing and rotatably connected to the housing, and a gearbox assembly drively connected to the output end of the rotor assembly, the stator assembly being disposed around the rotor assembly and spaced apart from the rotor assembly; the housing comprising an outer shell and a first end cover and a second end cover respectively fixed to both ends of the outer shell, the gearbox assembly being fixed to the side of the second end cover away from the outer shell; the rotor assembly comprising a rotating shaft rotatably connected to the first end cover and the second end cover respectively, and a permanent magnet sleeved and fixed to the rotating shaft, the outer periphery of the permanent magnet being spaced apart from the stator assembly; characterized in that, The stepper motor further includes a spring sheet with a flat plate structure and fixed to the first end cover. The spring sheet includes a limiting part abutting against the end of the rotating shaft away from the gearbox assembly, a ring-shaped fixing part surrounding the limiting part, and at least two spring arms connecting the limiting part and the fixing part; the fixing part is fixed to the first end cover.
2. The stepper motor according to claim 1, characterized in that, The limiting part has a circular structure and is located at the center of the fixing part; the spring arm includes three spring arms, which are arranged symmetrically about the center of the limiting part.
3. The stepper motor according to claim 2, characterized in that, The width of the spring arm gradually decreases from its two ends toward the middle.
4. The stepper motor according to claim 3, characterized in that, The spring arm is arc-shaped.
5. The stepper motor according to claim 1, characterized in that, The stepper motor also includes a first bearing and a second bearing. The inner circumferential side of the first bearing is sleeved and fixed to the end of the shaft away from the gearbox assembly. The outer circumferential side of the first bearing is inserted and fixed to the first end cover, and the side of the first bearing away from the permanent magnet abuts against the limiting part. The inner circumferential side of the second bearing is sleeved and fixed to one end of the rotating shaft near the gearbox assembly, and the outer circumferential side of the second bearing is inserted and fixed to the second end cover. The end of the gearbox assembly near the housing is sleeved with the second bearing.
6. The stepper motor according to claim 1, characterized in that, The housing further includes claw poles inserted and fixed to the outer shell, the claw poles and the outer shell together forming a mounting position; the stator assembly is sleeved and fixed to the outer shell and located within the mounting position; the stepper motor further includes a frame fixed to the housing, the frame including a ring-shaped frame body and a connecting portion extending from the frame body along an axial direction perpendicular to the rotating shaft; the frame body fixes the outer shell and is located within the mounting position, and the stator assembly is sleeved and fixed to the outer periphery of the frame.
7. The stepper motor according to claim 6, characterized in that, The stepper motor also includes a circuit board assembly, which is fixed to the end of the connection portion away from the housing.
8. The stepper motor according to claim 1, characterized in that, The stepper motor further includes a first pad and a second pad, which are respectively attached and fixed to the opposite ends of the permanent magnet, with the first pad spaced apart from the first end cap and the second pad spaced apart from the second end cap.
9. The stepper motor according to claim 1, characterized in that, The rotating shaft includes a rotating shaft body that is rotatably connected to the first end cover and the second end cover, a rotating shaft extension that extends from the rotating shaft body into the gearbox assembly, a limiting platform formed by the radial inward recess of the outer peripheral side of the rotating shaft extension, and a screw fixed to the limiting platform. The gearbox assembly includes a housing that fixes the second end cover, a rotating shaft disposed on the housing and forming a rotatable connection, and a gear sleeved and fixed to the rotating shaft; the rotating shaft is arranged perpendicular to the rotating shaft, and the gear is threadedly connected to the screw.
10. The stepper motor according to claim 9, characterized in that, The stepper motor also includes a vibration damping block, which is fixed inside the housing, and the end of the shaft extension away from the shaft body abuts against the vibration damping block.