US-20260128657-A1 - STEP MOTOR

US20260128657A1US 20260128657 A1US20260128657 A1US 20260128657A1US-20260128657-A1

Abstract

Provided is a step motor including a housing, a stator assembly, a rotor assembly, and a reduction gearbox assembly. The housing includes an outer shell as well as a first end cover and a second end cover, and the rotor assembly includes a rotary shaft and a permanent magnet. The step motor further includes an elastic piece fixed to the first end cover, the elastic piece includes a limiting portion, a ring-shaped fixing portion arranged around the limiting portion, and at least two elastic arms connecting the limiting portion with the fixing portion, and the fixing portion is fixed to the first end cover. Compared with the related art, the step motor of the present disclosure has high transmission precision, a small backlash, good vibration damping and noise reduction capabilities, as well as small volume occupation and low cost.

Inventors

Feng Yan
Junxiang Han
Junsheng Wang

Assignees

AAC MICROTECH (CHANGZHOU) CO., LTD.

Dates

Publication Date: 20260507
Application Date: 20250124

Claims (10)

1 . A step motor, comprising a housing, a stator assembly fixed to an inner peripheral side of the housing, a rotor assembly supported by the housing and rotationally connected to the housing, and a reduction gearbox assembly connected to an output end of the rotor assembly for power transmission; wherein the stator assembly is arranged around the rotor assembly and spaced apart from the rotor assembly, the housing comprises an outer shell and a first end cover and a second end cover respectively fixed to both ends of the outer shell, the reduction gearbox assembly is fixed on a side of the second end cover away from the outer shell, the rotor assembly comprises a rotary shaft rotationally connected to the first end cover and the second end cover, respectively, as well as a permanent magnet sleeved on and fixed to the rotary shaft, and an outer peripheral side of the permanent magnet is spaced apart from the stator assembly; and wherein the step motor further comprises an elastic piece having a flat plate structure and fixed to the first end cover, the elastic piece comprises a limiting portion abutting against an end of the rotary shaft away from the reduction gearbox assembly, a ring-shaped fixing portion arranged around the limiting portion, and at least two elastic arms connecting the limiting portion with the fixing portion, and the fixing portion is fixed to the first end cover.
2 . The step motor as described in claim 1 , wherein the limiting portion has a circular structure and is located in the center of the fixing portion, the number of the elastic arms is three, and the three elastic arms are arranged in a centrally symmetrical manner about the center of the limiting portion.
3 . The step motor as described in claim 2 , wherein a width of each of the elastic arms decreases gradually from both ends towards the middle.
4 . The step motor as described in claim 3 , wherein each of the elastic arms is in an arc shape.
5 . The step motor as described in claim 1 , wherein the step motor further comprises a first bearing and a second bearing, an inner peripheral side of the first bearing is sleeved on and fixed to the end of the rotary shaft away from the reduction gearbox assembly, an outer peripheral side of the first bearing is inserted into and fixed to the first end cover, and a side of the first bearing away from the permanent magnet abuts against the limiting portion; and an inner peripheral side of the second bearing is sleeved on and fixed to an end of the rotary shaft close to the reduction gearbox assembly, an outer peripheral side of the second bearing is inserted into and fixed to the second end cover, and an end of the reduction gearbox assembly close to the housing is sleeved on the second bearing.
6 . The step motor as described in claim 1 , wherein the housing further comprises a claw-pole inserted into and fixed to the outer shell, the claw-pole and the outer shell together enclose to form a mounting site, the stator assembly is sleeved on and fixed to the outer shell, and is located in the mounting site; the step motor further comprises a framework fixed to the housing, the framework comprises an annular framework body and a connecting portion extending along a direction perpendicular to an axial direction of the rotary shaft from the framework body, the framework body fixes the outer shell and is located in the mounting site, and the stator assembly is sleeved on and fixed to an outer peripheral side of the framework.
7 . The step motor as described in claim 6 , wherein the step motor further comprises a circuit board assembly fixed to an end of the connecting portion away from the outer shell.
8 . The step motor as described in claim 1 , wherein the step motor further comprises a first spacer and a second spacer, the first spacer and the second spacer are respectively attached and fixed to opposite ends of the permanent magnet, and the first spacer is spaced apart from the first end cover and the second spacer is spaced apart from the second end cover.
9 . The step motor as described in claim 1 , wherein the rotary shaft comprises a rotary shaft body rotationally connected to with the first end cover and the second end cover, respectively, a rotary shaft extension extending from the rotary shaft body into the reduction gearbox assembly, a limiting member formed by an outer peripheral side of the rotary shaft extension recessing radially inwards and a screw sleeved on and fixed to the limiting member; and the reduction gearbox assembly comprises a box for fixing the second end cover, a rotating shaft arranged in the box and rotationally connected to, and a gear sleeved on and fixed to the rotating shaft, the rotating shaft is arranged perpendicularly to the rotary shaft, and the gear forms a threaded connection with the screw.
10 . The step motor as described in claim 9 , wherein the step motor further comprises a vibration damping block fixed in the box, and an end of the rotary shaft extension away from the rotary shaft body abuts against the vibration damping block.

Description

TECHNICAL FIELD The present disclosure relates to the technical field of motors, and in particular, to a step motor. BACKGROUND Step motors have been widely used in the fields of electric motors, electric generators and the like due to their compact structure, high power density, high work efficiency, and significant energy saving and consumption reduction benefits. In recent years, there is an increasingly urgent demand in the industrial field for devices that utilize step motors to directly drive loads for work, and the widespread application of these step motor direct-drive devices will produce immeasurable energy-saving benefits. In related technologies, most of the step motors include an outer shell, a rotor, and a stator arranged around the rotor at intervals, as well as a gearbox, a motor rotation is realized by mutual driving of the stator and the rotor, and the gearbox is driven by an output shaft of the motor for power transmission. The stator includes a winding fixed to an outer peripheral side of the outer shell, the rotor generally includes a rotary shaft and a magnet fixed to an outer peripheral side of the rotary shaft, and the motor rotation is realized by mutual driving of the magnet and the winding. However, for the gearbox structure in the related technologies, when the motor is subjected to axial force, the movement of the shaft of the motor will cause a significant reduction in power transmission precision (which is accumulated when changing direction), and at the moment of starting, an end of the shaft moves rapidly due to the force and hits the fixing members, thus generating noise. In order to reduce the noise, a single-arm elastic piece formed by stamping is arranged on one side of the outer shell, and the single-arm elastic piece abuts against the end of the rotary shaft and its outer side is fixed to the outer shell. However, the single-arm elastic piece is prone to failure in the position near the root portion or welding point peeling in the long-term stress state. Moreover, since it requires a bending process, its structural features are relatively complex, which leads to an increase in production costs. Furthermore, during the handling process, it is easy to deform. When in use, it may be subjected to unilateral force. In addition, it has high thickness requirements, poor design flexibility, as well as insufficient reliability. Therefore, it is necessary to provide a novel step motor to solve the above technical problems. SUMMARY Objectives of the present disclosure are to provide a step motor that has higher power transmission precision, realizes a smaller backlash and better vibration damping, as well as noise reduction capabilities. In addition, it has a small volume occupation and low cost. In order to achieve the above objectives, the present disclosure provides a step motor including a housing, a stator assembly fixed to an inner peripheral side of the housing, a rotor assembly supported by the housing and rotationally connected to with the housing, and a reduction gearbox assembly connected to an output end of the rotor assembly for power transmission; where the stator assembly is arranged around the rotor assembly and spaced apart from the rotor assembly, the housing includes an outer shell as well as a first end cover and a second end cover respectively fixed to both ends of the outer shell, the reduction gearbox assembly is fixed on a side of the second end cover away from the outer shell, the rotor assembly includes a rotary shaft rotationally connected to with the first end cover and the second end cover, respectively, as well as a permanent magnet sleeved on and fixed to the rotary shaft, and an outer peripheral side of the permanent magnet is spaced apart from the stator assembly; and where the step motor further includes an elastic piece having a flat plate structure and fixed to the first end cover, the elastic piece includes a limiting portion abutting against an end of the rotary shaft away from the reduction gearbox assembly, a ring-shaped fixing portion arranged around the limiting portion, and at least two elastic arms connecting the limiting portion with the fixing portion, and the fixing portion is fixed to the first end cover. As an improvement, the limiting portion has a circular structure and is located in the center of the fixing portion, and the number of the elastic arms is three, and the three elastic arms are arranged in a centrally symmetrical manner about the center of the limiting portion. As an improvement, a width of each of the elastic arms decreases gradually from both ends towards the middle. As an improvement, each of the elastic arms is in an arc shape. As an improvement, the step motor further includes a first bearing and a second bearing arranged opposite to each other, an inner peripheral side of the first bearing is sleeved on and fixed to the end of the rotary shaft away from the reduction gearbox assembly, an outer peripheral side