Stepping motor

Abstract

The utility model relates to the technical field of motors, and provides a stepping motor which comprises a shell, a stator assembly, a rotor assembly and a reduction gearbox assembly in transmission connection with the output end of the rotor assembly, and the stator assembly is arranged around the rotor assembly and is spaced from the rotor assembly; the shell comprises an outer shell, a first end cover and a second end cover; the rotor assembly comprises a rotating shaft which is rotatably connected with the first end cover and the second end cover, and a permanent magnet which sleeves and is fixed on the rotating shaft. The stepping motor further comprises an elastic piece which is of a flat plate structure and fixed to the first end cover. The elastic piece comprises a limiting part abutting against the end, away from the reduction gearbox assembly, of the rotating shaft, an annular fixing part arranged around the limiting part, and at least two elastic arms connected with the limiting part and the fixing part. The fixing part is fixed to the first end cover. Compared with the prior art, the stepping motor provided by the utility model has the advantages of high transmission precision, small return stroke difference, good shock absorption and noise reduction capability, small occupied volume and low cost.

Description

TECHNICAL FIELD

[0001] The utility model relates to motor technical field especially relates to a step motor. BACKGROUND

[0002] Step motor is compact in structure, high in power density, high in working efficiency, remarkable in energy saving and consumption reducing benefit, and has been widely applied in the field of motor and generator. In recent years, the demand of industrial field for the equipment directly driven by step motor is more and more urgent, and the wide application of these step motor direct drive equipment will produce immeasurable energy saving benefit.

[0003] In the related art, the existing step motor mostly comprises a shell, a rotor, a stator spacedly wound on the rotor and a gear box, the motor is rotated by mutual driving of the stator and the rotor, and the gear box is driven by the output shaft of the motor to transmit power. The stator comprises a winding fixed to the outer circumferential side of the shell, and the rotor generally comprises a rotating shaft and a magnetic steel fixed to the outer circumferential side of the rotating shaft, the motor is rotated by mutual driving of the magnetic steel and the winding. However, when the motor bears axial force, the shaft movement of the motor will cause significant decrease in transmission accuracy (accumulation during commutation), and the shaft end will impact the fixed part due to rapid movement under force at the starting moment, generating noise. In order to reduce the noise, a single-arm spring sheet formed by stamping is arranged on one side of the shell, the single-arm spring sheet abuts against the end of the rotating shaft and is fixed to the shell on the outside. However, the single-arm spring sheet is prone to failure or peeling off of the welding point at the position close to the root under long-term stress, and the single-arm spring sheet has a bending process, the structure is complex, the production cost is high, the turnover is prone to deformation, the use process is one-sided stress, the thickness requirement is high, the design flexibility is poor, and the reliability is insufficient.

[0004] Therefore, it is necessary to provide a new step motor to solve the above technical problems. UTILITY MODEL CONTENTS

[0005] The utility model aims at providing a step motor with higher transmission accuracy, smaller return difference, better shock absorption and noise reduction capacity, small volume, low cost and the like.

[0006] In order to achieve the above object, the utility model provides a kind of step motor, it includes shell, stator assembly fixed to the inner circumferential side of the shell, rotator assembly supported in the shell and with the shell form rotating connection and the output end of the reduction gearbox assembly connected to the rotator assembly, the stator assembly is arranged around the rotator assembly and is spaced apart from the rotator assembly;The shell includes shell and the first end cover and the second end cover fixed to the both ends of the shell respectively, the reduction gearbox assembly is fixed to the side of the second end cover away from the shell;The rotator assembly includes rotating shaft and permanent magnet fixed to the rotating shaft with the first end cover and the second end cover form rotating connection respectively, the outer circumferential side of the permanent magnet is spaced apart from the stator assembly;Its characterized in that,

[0007] The step motor further includes the sheet fixed to the first end cover and presented flat plate structure, the sheet includes the limiting portion abutting to the one end of the rotating shaft away from the reduction gearbox assembly, the fixed portion presented annularly arranged around the limiting portion, and at least two elastic arms connecting the limiting portion and the fixed portion;The fixed portion is fixed to the first end cover.

[0008] Preferably, the limiting portion is circular structure, and is located at the central position of the fixed portion;The elastic arm includes three, three the elastic arm is about the center of the limiting portion and is centrally symmetrically arranged.

[0009] Preferably, the width of the elastic arm gradually decreases from both ends to the middle.

[0010] Preferably, the elastic arm is arc-shaped.

[0011] Preferably, the step motor further includes the first bearing and the second bearing oppositely arranged, the inner circumferential side of the first bearing is fixedly sleeved to the one end of the rotating shaft away from the reduction gearbox assembly, the outer circumferential side of the first bearing is fixedly inserted to the first end cover, and the side of the first bearing away from the permanent magnet abuts to the limiting portion;

[0012] The inner circumferential side of the second bearing is fixedly sleeved to the one end of the rotating shaft close to the reduction gearbox assembly, the outer circumferential side of the second bearing is fixedly inserted to the second end cover, and the one end of the reduction gearbox assembly close to the shell is fixedly sleeved to the second bearing.

[0013] Preferably, the shell further comprises a claw pole fixedly inserted into the shell, the claw pole and the shell jointly defining a mounting position; the stator assembly is fixedly sleeved to the shell and located in the mounting position; the stepping motor further comprises a framework fixed to the shell, the framework comprising a framework body in a ring shape and a connecting portion extending from the framework body along an axial direction perpendicular to the rotating shaft; the framework body is fixed to the shell and located in the mounting position, and the stator assembly is fixedly sleeved to an outer circumferential side of the framework.

[0014] Preferably, the stepping motor further comprises a circuit board assembly fixed to an end of the connecting portion away from the shell.

[0015] Preferably, the stepping motor further comprises a first gasket and a second gasket, the first gasket and the second gasket are respectively fixedly attached to opposite ends of the permanent magnet, and the first gasket is spaced apart from the first end cover, and the second gasket is spaced apart from the second end cover.

[0016] Preferably, the rotating shaft comprises a rotating shaft body rotatably connected to the first end cover and the second end cover, a rotating shaft extension portion extending from the rotating shaft body into the reduction box assembly, a limiting platform recessed inwardly along a radial direction of the rotating shaft extension portion, and a screw rod fixedly sleeved to the limiting platform.

[0017] The reduction box assembly comprises a box body fixed to the second end cover, a rotating shaft arranged in the box body and rotatably connected, and a gear fixedly sleeved to the rotating shaft; the rotating shaft is arranged vertically to the rotating shaft, and the gear is threadedly connected to the screw rod.

[0018] Preferably, the stepping motor further comprises a damping block fixedly arranged in the box body, and an end of the rotating shaft extension portion away from the rotating shaft body abuts against the damping block.

[0019] Compared with the prior art, the step motor has the following advantages: the stator assembly is fixed in the shell, the rotor assembly is rotationally connected with the shell, the stator assembly is arranged around the rotor assembly and is spaced from the rotor assembly, the magnetic field generated by the stator assembly and the rotor assembly drives the reduction box assembly to transmit, the stator assembly is sleeved and fixed in the shell and located in the mounting position, the reduction box assembly is fixed on the side of the second end cover away from the shell, the rotor assembly is rotationally connected with the first end cover and the second end cover, the rotor assembly comprises a rotating shaft rotationally connected with the first end cover and the second end cover and a permanent magnet sleeved and fixed on the rotating shaft, the outer circumferential side of the permanent magnet is spaced from the stator assembly, the step motor further comprises a spring sheet in a flat plate structure and fixed on the first end cover, the spring sheet comprises a limiting portion abutting against one end of the rotating shaft away from the reduction box assembly, a fixing portion in a ring shape arranged around the limiting portion, and at least two elastic arms connecting the limiting portion and the fixing portion, and the fixing portion is fixed on the first end cover, the spring sheet has the advantages of smaller return difference, better shock absorption and noise reduction capacity, small volume, low cost and strong popularization. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor, and the drawings are as follows:

[0021] Figure 1 The figure shows the three-dimensional structure of the step motor provided by the embodiment of the present application.

[0022] Figure 2 The figure shows the three-dimensional structure of the step motor provided by the embodiment of the present application.

[0023] Figure 3 The figure shows the A-A line section view of the step motor. Figure 1

[0024] The figure shows the structure of the spring sheet provided by the embodiment of the present application. Figure 4

[0025] ​Wherein, 100, stepper motor, 1, shell, 11, shell, 12, first end cover, 13, second end cover, 14, claw pole, 15, installation site, 2, stator assembly, 3, rotor assembly, 31, permanent magnet, 32, rotating shaft, 321, rotating shaft body, 322, limit table, 323, screw, 324, rotating shaft extension, 4, reduction box assembly, 41, box, 42, rotating shaft, 43, gear, 5, elastic sheet, 51, limiting portion, 52, elastic arm, 53, fixed part, 6, first bearing, 7, second bearing, 8, skeleton, 81, skeleton body, 82, connecting part, 9, circuit board assembly, 10, first gasket, 20, second gasket, 30, damping block. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0027] In combination with Figures 1 to 4 As shown in the accompanying drawings, the embodiment of the present application provides a stepper motor 100, which comprises a shell 1, a stator assembly 2 fixed to the inner circumferential side of the shell 1, a rotor assembly 3 supported on the shell 1 and forming a rotating connection with the shell 1, and a reduction box assembly 4 transmission connected to the output end of the rotor assembly 3, the stator assembly 2 is arranged around the rotor assembly 3 and is spaced apart from the rotor assembly 3; the shell 1 comprises a shell 11 and a first end cover 12 and a second end cover 13 fixed to both ends of the shell 11 respectively, the stator assembly 2 is fixed to the shell 11 and located in the installation site 15, the reduction box assembly 4 is fixed to the side of the second end cover 13 away from the shell 11, and the rotor assembly 3 is rotatably connected with the first end cover 12 and the second end cover 13 respectively. The shell 1 is used for mounting and fixing the first end cover 12 and the second end cover 13.

[0028] In the embodiment, the stator assembly 2 is a coil winding, and the coil winding is arranged around the rotor assembly 3. Optionally, the stator assembly 2 can be at least two, and the two stator assemblies 2 are arranged side by side along the axial direction of the rotating shaft 32 assembly.

[0029] The rotor assembly 3 comprises a rotating shaft 32 and a permanent magnet 31 fixed on the rotating shaft 32, which are rotatably connected with the first end cover 12 and the second end cover 13 respectively, and the outer periphery of the permanent magnet 31 is spaced apart from the stator assembly 2. The rotation of the rotating shaft 32 is driven by the magnetic field generated by the permanent magnet 31 and the stator assembly 2, so as to drive the reduction box assembly 4 to move.

[0030] The stepping motor 100 further comprises a spring sheet 5 in a flat plate structure and fixed on the first end cover 12. The spring sheet 5 comprises a limiting portion 51 abutting against one end of the rotating shaft 32 away from the reduction box assembly 4, a fixing portion 53 in a ring shape arranged around 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 on the first end cover 12. By abutting the limiting portion 51 of the spring sheet 5 against the rotating shaft 32 and fixing the fixing portion 53 on the first end cover 12, the spring arms 52 achieve smaller return difference, better shock absorption and noise reduction, and have the advantages of small volume, low cost and strong promotion. Further, by introducing the flat spring sheet 5, the gap between the rotor assembly 3 and the cumulative error of the parts of the motor are effectively eliminated, so as to ensure that the system maintains high transmission accuracy and low noise performance. At the same time, the spring sheet 5 can provide shock absorption when falling, improving the reliability of the mechanism. The whole structure is under stress during use, and the failure risk is small. The design flexibility is high, the thickness can be reduced, and the volume is smaller.

[0031] In this embodiment, the fixing portion 53 is fixed on the first end cover 12 by welding or other processes.

[0032] In this embodiment, the limiting portion 51 is in a circular structure and located at the center of the fixing portion 53. The spring arms 52 comprise three, which are arranged in central symmetry about the center of the limiting portion 51.

[0033] Preferably, there are two or more spring arms 52, and the recommended number n is greater than or equal to 3, and in this embodiment, the number is 3. The actual number is not limited. The two ends of the spring arm 52 are connected to the limiting portion 51 of the inner circle and the fixing portion 53 of the outer ring respectively, and are arranged in central symmetry along the center of the limiting portion 51, so as to ensure that the mechanism is under symmetrical stress, and has better stability and reliability.

[0034] In this embodiment, the width of the spring arm 52 gradually decreases from the two ends to the middle, so as to ensure better stress performance.

[0035] In the embodiment, the elastic arm 52 is arc-shaped. The arc-shaped structure (a structure with a reinforcing rib) is generally designed to be gradually narrower from the end to the middle, which ensures better stress performance. The arc-shaped design provides a certain degree of axial pre-tightening force, which is recommended to be designed to be greater than the axial force to the left (away from the side of the reduction box assembly 4) of the gear 43 to the shaft 32 when the transmission load is greater, which ensures the stability of the system at a very high transmission accuracy.

[0036] In the embodiment, the stepping motor 100 further comprises a first bearing 6 and a second bearing 7 arranged oppositely. The inner circumferential side of the first bearing 6 is sleeved and fixed to one end of the shaft 32 away from the reduction box assembly 4, the outer circumferential side of the first bearing 6 is inserted and fixed to the first end cover 12, and the side of the first bearing 6 away from the permanent magnet 31 abuts against the elastic arm 52. By abutting the end of the elastic arm 52 and the first bearing 6, the torque output of the motor can be better guaranteed, but it is not limited to the use scene, such as abutting against the end of the shaft 32, which still belongs to the scope of patent protection.

[0037] The inner circumferential side of the second bearing 7 is sleeved and fixed to one end of the shaft 32 close to the reduction box assembly 4, the outer circumferential side of the second bearing 7 is inserted and fixed to the second end cover 13, and one end of the reduction box assembly 4 close to the shell 1 is sleeved in the second bearing 7. By sleeving the first bearing 6 and the second bearing 7 on both ends of the shaft 32, the friction during rotation of the shaft 32 is small, the rotation power loss is low, and the output accuracy of the motor is high.

[0038] In the embodiment, the shell 1 further comprises a claw pole 14 inserted and fixed to the outer shell 11, the claw pole 14 and the outer shell 11 jointly form a mounting position 15; the stator assembly 2 is sleeved and fixed to the outer shell 11 and located in the mounting position 15; the stepping motor 100 further comprises a framework 8 fixed to the shell 1, the framework 8 comprises a framework body 81 in a ring shape and a connecting part 82 extending along the axial direction perpendicular to the shaft 32 from the framework body 81; the framework body 81 fixes the outer shell 11 and is located in the mounting position 15, and the stator assembly 2 is sleeved and fixed to the outer circumferential side of the framework 8. The framework body 81 is used for mounting and fixing the stator assembly 2, so that the stator assembly 2 is stable during driving of the rotor assembly 3. The shell 1 and the claw pole 14 are inserted with each other to form the mounting position 15, which facilitates the circumferential installation of the stator assembly 2.

[0039] In the embodiment, the stepping motor 100 further comprises a circuit board assembly 9 fixed to one end of the connecting part 82 away from the outer shell 11. The circuit board assembly 9 is used for providing power supply for the stator assembly 2, so that the stator assembly 2 drives to generate a magnetic field, which facilitates mutual driving with the rotor assembly 3 and drives the shaft 32 to rotate.

[0040] The step motor 100 further comprises a first gasket 10 and a second gasket 20, which are respectively fixed to opposite ends of the permanent magnet 31, and the first gasket 10 is spaced from the first end cover 12, and the second gasket 20 is spaced from the second end cover 13. The fixing effect of the permanent magnet 31 is improved.

[0041] The rotating shaft 32 comprises a rotating shaft body 321 rotatably connected with 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 reduction box assembly 4, a limiting table 322 recessed radially inward from the outer circumferential side of the rotating shaft extension 324, and a screw rod 323 sleeved and fixed to the limiting table 322.

[0042] The reduction box assembly 4 comprises a box body 41 fixed with the second end cover 13, a rotating shaft 42 rotatably arranged in the box body 41, and a gear 43 sleeved and fixed to the rotating shaft 42; the rotating shaft 42 is arranged vertically to the rotating shaft 32, and the gear 43 is threadedly connected with the screw rod 323. The rotating shaft 32 drives the screw rod 323 to rotate to drive the gear 43 to rotate, and the gear 43 rotates to realize the function of the speed reducer.

[0043] The step motor 100 further comprises a damping block 30 fixed in the box body 41, and one end of the rotating shaft extension 324 away from the rotating shaft body 321 abuts against the damping block 30. During falling or impact, the rotating shaft 32 moves instantaneously away from the reduction box assembly 4, the spring piece 5 deforms to provide shock absorption and buffering effect, and the reliability of the structure of the gear 43 is ensured. The design and optimization of the spring arm 52 ensure that it is in the best elastic deformation range.

[0044] The damping block 30 is made of silica gel material, has high structural strength, and has good damping effect.

[0045] Compared with the prior art, the step motor has the following advantages: the stator assembly is fixed in the shell, the rotor assembly is rotationally connected with the shell, the stator assembly is arranged around the rotor assembly and is spaced from the rotor assembly, the magnetic field generated by the stator assembly and the rotor assembly drives the reduction box assembly to transmit, the stator assembly is sleeved and fixed in the shell and located in the mounting position, the reduction box assembly is fixed on the side of the second end cover away from the shell, the rotor assembly is rotationally connected with the first end cover and the second end cover, the rotor assembly comprises a rotating shaft rotationally connected with the first end cover and the second end cover and a permanent magnet sleeved and fixed on the rotating shaft, and the outer circumferential side of the permanent magnet is spaced from the stator assembly, the step motor further comprises a spring sheet in a flat plate structure and fixed on the first end cover, the spring sheet comprises a limiting portion abutting against one end of the rotating shaft away from the reduction box assembly, a fixing portion in a ring shape arranged around the limiting portion, and at least two elastic arms connecting the limiting portion and the fixing portion, and the fixing portion is fixed on the first end cover, the limiting portion of the spring sheet abuts against the rotating shaft, the fixing portion is fixed on the first end cover, the elastic arms achieve smaller return difference, better shock absorption and noise reduction capacity, and have the advantages of small volume, low cost and strong popularization.

[0046] The above only describes the embodiments of the utility model, and it should be pointed out that, for those skilled in the art, improvements can be made without departing from the creative concept of the utility model, but these all belong to the protection scope of the 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.

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