Stepping motor

Abstract

The utility model relates to the technical field of motors, in particular to a stepping motor, which comprises a shell, a hollow stator module, a rotor and a rotating shaft, the shell is provided with an accommodating cavity, the stator module is arranged in the accommodating cavity, the rotor is arranged in the stator module, the rotating shaft penetrates through the rotor and is fixedly connected with the rotor, and the rotating shaft protrudes out of the shell; the motor further comprises a first bearing and a second bearing, the rotating shaft is sleeved with the first bearing and the second bearing, the first bearing and the second bearing are located at the two ends of the rotor respectively, the first bearing is provided with a first limiting part, the rotor is provided with a second limiting part, and the first bearing and the rotor can abut against each other through the first limiting part and the second limiting part. And gaps exist between the rest positions of the first bearing and the rest positions of the rotor. According to the stepping motor, the contact area between the rotor and the bearing can be reduced when the stepping motor is axially stressed, so that the torque loss of the motor is reduced.

Description

Technical Field

[0001] This utility model relates to the field of motor technology, and more specifically, to a stepper motor. Background Technology

[0002] A stepper motor is a type of motor that converts electrical pulse signals into mechanical angular displacement. It achieves precise angular displacement control and speed regulation by controlling the number, frequency, and direction of the input pulses. Stepper motors are widely used in applications requiring precise position control, such as industrial automation, robotics, 3D printing, medical equipment, and office automation. Stepper motors operate based on the principle of electromagnetic induction. By passing pulsed current through the stator windings, a magnetic field is generated, which in turn drives the rotor to rotate. Each input pulse signal causes the motor rotor to rotate by a fixed angle, called the step angle. By controlling the frequency and number of pulses, precise control of the motor's speed and position can be achieved.

[0003] In the prior art, when a stepper motor is subjected to axial force, the contact position between the rotor and the bearing is a planar support. The bearing supports both the upper and lower surfaces with large planar contact. Especially when subjected to axial load, the friction is large. At the same time, when the friction coefficient of the shim is high, it will lead to high torque loss of the motor. Utility Model Content

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies where the contact area between the rotor and the bearing is large, resulting in high torque loss of the motor. This invention provides a stepper motor that can reduce the contact area between the rotor and the bearing when subjected to axial force, thereby reducing the torque loss of the motor.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:

[0006] A stepper motor is provided, comprising a housing with a receiving cavity, a hollow stator module, a rotor, and a rotating shaft. The stator module is installed in the receiving cavity, the rotor is installed in the stator module, and the rotating shaft passes through the rotor and is fixedly connected to the rotor, with the rotating shaft protruding from the housing. The motor also includes a first bearing and a second bearing, both sleeved on the rotating shaft and located at opposite ends of the rotor. The first bearing has a first limiting portion, and the rotor has a second limiting portion. The first bearing and the rotor can abut against each other through the first limiting portion and the second limiting portion, with gaps existing between the remaining positions of the first bearing and the remaining positions of the rotor.

[0007] The stepper motor of this invention sets a limit at the contact position between the first bearing and the rotor, so that when the rotor is subjected to axial force, the first bearing and the rotor only contact at the first limit part and the second limit part, while the other positions of the first bearing and the other positions of the rotor do not contact each other. The gap between the other positions of the first bearing and the other positions of the rotor mentioned above is the absence of contact. Therefore, the contact area between the first bearing and the rotor is greatly reduced, thereby reducing the friction between the two, reducing the torque loss of the rotor, and extending the service life of the motor.

[0008] Furthermore, the first limiting part is a protrusion, and the second limiting part is a groove; or the first limiting part is a groove, and the second limiting part is a protrusion. The protrusion and groove cooperate to achieve abutment and limiting. Preferably, the height of the protrusion is greater than the depth of the groove, so that when the protrusion and groove cooperate, the first bearing and the rotor do not contact each other except at the limiting part, thereby reducing the friction between the first bearing and the rotor.

[0009] Furthermore, the first limiting part is arranged around the central axis of the first bearing, and the second limiting part is arranged around the central axis of the rotor. This arrangement ensures that the force is balanced when the first bearing contacts the rotor, which is beneficial for the smooth power output of the motor.

[0010] Furthermore, it also includes an elastic element, which is sleeved outside the rotating shaft. The elastic element is located between the housing and the first bearing, or between the first bearing and the rotor, or between the rotor and the second bearing, or between the second bearing and the stator module, or between the second bearing and the housing. The elastic element provides a buffer clearance using its restoring force when the motor is subjected to axial force, thereby reducing friction between the first bearing and the rotor, reducing torque loss of the motor, and extending the service life of the motor. Preferably, the elastic element can be a spring or a ring-shaped spring sheet, used to absorb part of the axial force.

[0011] Furthermore, both the first bearing and the second bearing partially protrude from the housing; or both the first bearing and the second bearing are located within the housing. The partial protrusion of the first and second bearings from the housing facilitates their connection and installation with other components. Specifically, the positional relationship between the first and second bearings and the housing can be adjusted according to actual needs.

[0012] Furthermore, the rotor has a countersunk hole at the second limiting part, the countersunk hole being located inside the second limiting part. The elastic element is accommodated within the countersunk hole, with one end of the elastic element abutting against the first bearing and the other end abutting against the rotor. The countersunk hole can be used to install the elastic element. Preferably, the elastic element is a spring, with two washers respectively provided at the upper and lower ends of the elastic element. The elastic element contacts both the upper and lower washers, with the upper washer contacting the first bearing and the lower washer contacting the rotor. The elastic element is placed between the rotor and the first bearing, forming a buffer gap structure with the upper and lower washers. When the elastic element is subjected to downward pressure towards the rotor, it uses its restoring force to lift the first bearing, minimizing the contact between the first bearing and the rotor.

[0013] Furthermore, the elastic element is sleeved on the outside of the second bearing, with one end abutting against the second bearing and the other end abutting against the stator module. The housing includes a detachably connected end cap and a main body. The main body has an annular cross-section, with a receiving cavity located within it. The end cap has a similar shape to the main body, and together with the main body, they partially enclose the stator module. The rotor is located within the stator module, specifically within the annular hole of the main body. Further, a cover plate is included, positioned above the end cap, for limiting the installation of the first bearing. In this structure, the second bearing is installed within and abuts against the stator module. The elastic element is an annular spring sheet. A limiting step is provided at the bottom of the second bearing. The elastic element is sleeved on the outside of the bottom of the second bearing. When the shaft applies force to the second bearing, the elastic element provides a reaction force, acting on the second bearing, and subsequently on the shaft and rotor, driving the rotor to move upward and abut against the first bearing.

[0014] Furthermore, the second bearing has a blind hole with a tapered bottom. The shaft is inserted into the blind hole, and its end abuts against the bottom of the blind hole. The end of the shaft has an arc-shaped structure. The arc-shaped structure of the shaft abuts against the tapered structure of the blind hole in the second bearing, creating a buffer between the shaft and the second bearing. Compared to the prior art where the shaft and second bearing have a large planar contact, the structure of the shaft and second bearing in this invention can appropriately reduce the friction between them and make the force more balanced. Preferably, the cone angle of the tapered structure is 130°.

[0015] Furthermore, the cross-sectional area of ​​the blind hole near the top is larger than that near the bottom. This arrangement facilitates the fit between the shaft and the second bearing, reducing the contact between the outer wall of the shaft and the inner wall of the blind hole, thus reducing friction and wear.

[0016] Furthermore, the first bearing is provided with a through hole, and the rotating shaft is inserted into the through hole. The cross-sectional area of ​​the through hole near the rotor end is larger than the cross-sectional area away from the rotor end. This arrangement facilitates the fit between the rotating shaft and the first bearing, thereby reducing the contact between the outer wall of the rotating shaft and the inner wall of the first bearing, reducing friction, and mitigating wear.

[0017] Compared with the prior art, the beneficial effects of this utility model are:

[0018] (1) By setting a first limiting part in the first bearing and a second limiting part in the rotor, when the first bearing and the rotor are in contact, only the first limiting part and the second limiting part abut against each other, and the other parts do not contact each other. This greatly reduces the contact area between the first bearing and the rotor when the rotor is subjected to axial force, thereby reducing the friction between the two, reducing the torque loss of the rotor, and extending the service life of the motor.

[0019] (2) By setting up elastic elements, a buffer gap is provided when the rotor is subjected to axial force, which can further reduce rotor wear and extend the service life of the motor. Attached Figure Description

[0020] Figure 1 This is a first-view structural schematic diagram of a stepper motor according to the present invention;

[0021] Figure 2 This is a structural schematic diagram of a stepper motor from a second perspective according to the present invention;

[0022] Figure 3 This is a structural schematic diagram of a stepper motor from a third-view perspective according to the present invention;

[0023] Figure 4 This is an exploded view of a stepper motor according to the present invention;

[0024] Figure 5 for Figure 3 AA cross-sectional view of Embodiment 1;

[0025] Figure 6 for Figure 3 AA cross-sectional view for Embodiment 2.

[0026] The markings in the diagram are explained below:

[0027] 1. Housing; 11. End cap; 12. Main body; 13. Cover plate; 2. Stator module; 3. Rotor; 31. Second limiting part; 4. Rotating shaft; 5. First bearing; 51. First limiting part; 52. Through hole; 6. Second bearing; 61. Blind hole; 7. Elastic element; 8. Gasket. Detailed Implementation

[0028] The present invention will be further described below with reference to specific embodiments. The accompanying drawings are for illustrative purposes only, representing schematic diagrams rather than actual physical objects, and should not be construed as limiting the scope of this patent. To better illustrate the embodiments of the present invention, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0029] In the accompanying drawings of this utility model, the same or similar reference numerals correspond to the same or similar components. In the description of this utility model, it should be understood that if terms such as "upper," "lower," "left," and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0030] Example 1

[0031] like Figures 1 to 5 The first embodiment of the stepper motor of this utility model is shown, including a housing 1 with a receiving cavity, a hollow stator module 2, a rotor 3, and a rotating shaft 4. The stator module 2 is installed in the receiving cavity, the rotor 3 is installed in the stator module 2, and the rotating shaft 4 passes through the rotor 3 and is fixedly connected to the rotor 3. The rotating shaft 4 protrudes from the housing 1. It also includes a first bearing 5 and a second bearing 6, both of which are sleeved on the outside of the rotating shaft 4 and are located at both ends of the rotor 3. The first bearing 5 is provided with a first limiting part 51, and the rotor 3 is provided with a second limiting part 31. The first bearing 5 and the rotor 3 can abut against each other through the first limiting part 51 and the second limiting part 31. There are gaps between the other positions of the first bearing 5 and the other positions of the rotor 3.

[0032] The stepper motor of this invention sets a limit at the contact position between the first bearing 5 and the rotor 3, so that when the rotor 3 is subjected to axial force, the first bearing 5 and the rotor 3 only contact each other at the first limit part 51 and the second limit part 31, while the other positions of the first bearing 5 and the other positions of the rotor 3 do not contact each other. The gap between the other positions of the first bearing 5 and the other positions of the rotor 3 mentioned above is the absence of contact. Therefore, the contact area between the first bearing 5 and the rotor 3 is greatly reduced, thereby reducing the friction between the two, reducing the torque loss of the rotor 3, and extending the service life of the motor.

[0033] In one embodiment of this utility model, the first limiting part 51 is a protrusion, and the second limiting part 31 is a groove. In this embodiment, the first limiting part 51 is a protrusion located at the bottom of the first bearing 5 and is arranged around the central axis of the first bearing 5. A rounded corner or a chamfer is provided on the circumferential edge of the protrusion for cooperating with the second limiting part 31. The second limiting part 31 is a groove located at the center of the rotor 3 and around the outer periphery of the rotating shaft 4. The second limiting part 31 is arranged around the central axis of the rotor 3 and a rounded corner or a chamfer is also provided on the circumferential inner wall of the groove to cooperate with the first limiting part 51. When the first bearing 5 contacts the rotor 3, the contact position is on the periphery of the first limiting part 51 and the second limiting part 31, while the end face of the first bearing 5 does not contact the end face of the rotor 3. Therefore, the contact area between the two is greatly reduced, thereby reducing the frictional force generated by the contact.

[0034] In one embodiment of this utility model, both the first bearing 5 and the second bearing 6 partially protrude from the housing 1. In this embodiment, limiting steps are provided on both the first bearing 5 and the second bearing 6. Through the cooperation of the limiting steps with the housing 1, the first bearing 5 and the second bearing 6 partially protrude from the housing 1. This arrangement facilitates the installation and connection of the first bearing 5 and the second bearing 6 with other components.

[0035] In one embodiment of this utility model, the rotor 3 has a countersunk hole at the second limiting part 31, located inside the second limiting part 31. It also includes an elastic element 7, which is sleeved outside the rotating shaft 4, between the first bearing 5 and the rotor 3. The elastic element 7 is accommodated within the countersunk hole, with one end abutting against the first bearing 5 and the other end abutting against the rotor 3. The countersunk hole is essentially a groove in the second limiting part 31 extending towards the center of the rotor 3. In this embodiment, the elastic element 7 is preferably a spring. Two washers 8 are respectively provided at the upper and lower ends of the elastic element 7, with the elastic element 7 contacting both the upper and lower washers 8. The upper washer 8 contacts the first bearing 5, and the lower washer 8 contacts the rotor 3. The elastic element 7 is positioned between the rotor 3 and the first bearing 5, forming a buffer gap structure with the upper and lower washers 8. When subjected to downward pressure towards the rotor 3, the elastic element 7 uses its restoring force to lift the first bearing 5, minimizing the contact between the first bearing 5 and the rotor 3, thereby reducing the friction between the first bearing 5 and the rotor 3 and reducing wear on the rotor 3.

[0036] In one embodiment of this utility model, the second bearing 6 has a blind hole 61 with a tapered bottom. A rotating shaft 4 is inserted into the blind hole 61, with its end abutting against the bottom of the blind hole 61. The end of the rotating shaft 4 has an arc-shaped structure. The arc-shaped structure of the rotating shaft 4 abuts against the tapered structure of the blind hole 61 of the second bearing 6, creating a buffer between them. Compared to the prior art where both the bottom of the rotating shaft and the bottom of the second bearing are flat, resulting in a large-area contact, the structure of the rotating shaft 4 and the second bearing 6 in this utility model can appropriately reduce the friction between them and make the force more balanced. Furthermore, the cone angle of the tapered structure is 130°±5°; preferably, the cone angle is 130°.

[0037] In one embodiment of this invention, the cross-sectional area of ​​the blind hole 61 near the top is larger than that near the bottom. This arrangement facilitates the fit between the rotating shaft 4 and the second bearing 6, thereby reducing the contact between the outer wall of the rotating shaft 4 and the inner wall of the blind hole 61, reducing friction, and mitigating wear.

[0038] In one embodiment of this utility model, the first bearing 5 is provided with a through hole 52, and the rotating shaft 4 is inserted into the through hole 52. The cross-sectional area of ​​the through hole 52 near the rotor 3 is larger than the cross-sectional area away from the rotor 3. Because there is an interference fit between the first bearing 5 and the housing 1, to avoid interference issues, the through hole 52 is designed with two diameter sections. Interference would cause the inner hole to shrink, while setting the diameter of the through hole 52 larger near the rotor 3 facilitates the fit between the rotating shaft 4 and the first bearing 5, reducing the contact between the outer wall of the rotating shaft 4 and the inner wall of the first bearing 5, reducing friction, and mitigating wear. Within the understanding of those skilled in the art, the diameter of the through hole 52 can also be made to transition sequentially, with the diameter near the rotor 3 being larger than the diameter away from the rotor 3.

[0039] Example 2

[0040] like Figure 6 The following is a second embodiment of a stepper motor according to the present invention. This embodiment is similar to the first embodiment, except that the first limiting part 51 is a groove, the second limiting part 31 is a protrusion, the elastic member 7 is located between the second bearing 6 and the stator module 2, the elastic member 7 is sleeved on the outside of the second bearing 6 and one end abuts against the second bearing 6, and the other end abuts against the stator module 2.

[0041] In this embodiment, the first limiting part 51 is an annular groove on the end face of the first bearing 5, and the second limiting part 31 is an annular protrusion on the end face of the rotor 3. The height of the protrusion is greater than the depth of the groove, so that when the protrusion and the groove are engaged, the first bearing 5 and the rotor 3 do not contact each other except for the limiting part, thereby reducing the friction between the first bearing 5 and the rotor 3. The housing 1 includes a detachably connected end cap 11 and a main body 12. The receiving cavity is located inside the main body 12. The cross-section of the main body 12 is annular. The stator module 2 is partially installed inside the main body 12, and the rotor 3 is located in the stator module 2. In this structure, the second bearing 6 is installed in the stator module 2 and abuts against it. The elastic element 7 is an annular spring sheet. The bottom of the second bearing 6 is provided with a limiting step. The elastic element 7 is sleeved on the outer side of the bottom of the second bearing 6. When the rotating shaft 4 applies force to the second bearing 6, the elastic element 7 provides a reaction force, which acts on the second bearing 6, and then on the rotating shaft 4 and the rotor 3, driving the rotor 3 to move upward and abut against the first bearing 5. In this embodiment, a spring structure can be used, similar to that in Embodiment 1, with the elastic element 7 disposed in the countersunk hole inside the rotor 3. Preferably, both the first bearing 5 and the second bearing 6 are made of ceramic. However, to the best of the knowledge of those skilled in the art, the first bearing 5 and the second bearing 6 can also be made of plastic.

[0042] Example 3

[0043] The following is a third embodiment of the stepper motor of this utility model. This embodiment is similar to embodiment 1, except that the first bearing 5 and the second bearing 6 are both located inside the housing 1, and the elastic element 7 is located between the housing 1 and the first bearing 5. The housing 1 includes a detachably connected end cap 11 and a main body 12. The main body 12 has an open end structure, and the receiving cavity is located inside the main body 12. The stator module 2 is located in the receiving cavity, and the rotor 3 is located at the center of the stator module 2. The rotating shaft 4 protrudes from the end cap 11. In this case, the first bearing 5 and the second bearing 6 can both be located in the receiving cavity, and the housing 1 can fully enclose the first bearing 5, the second bearing 6, the stator module 2, and the rotor 3, which is beneficial for protecting each component and improving the overall aesthetics. The elastic element 7 can be a spring or a ring-shaped spring sheet, which is sleeved on the outside of the rotating shaft 4 and is used to provide a buffer gap when the rotor 3 receives axial force, thereby reducing the wear of the rotor 3.

[0044] Example 4

[0045] The following is a fourth embodiment of a stepper motor according to the present invention. This embodiment is similar to embodiment 1, except that the elastic element 7 is located between the rotor 3 and the second bearing 6. The elastic element 7 can be a spring or an annular spring sheet, which is sleeved on the outside of the rotating shaft 4. When the rotor 3 receives axial force, it is used to provide a buffer gap to reduce the wear of the rotor 3.

[0046] Example 5

[0047] The following is the fifth embodiment of a stepper motor according to the present invention. This embodiment is similar to embodiment 3, except that the elastic element 7 is located between the second bearing 6 and the housing 1. The elastic element 7 can be a spring or an annular spring sheet, which is sleeved on the outside of the rotating shaft 4 to provide a buffer gap when the rotor 3 receives axial force, thereby reducing the wear of the rotor 3.

[0048] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating this utility model, and are not intended to limit the implementation of this utility model. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A stepper motor, comprising a housing (1) with a receiving cavity, a hollow stator module (2), a rotor (3), and a rotating shaft (4), wherein the stator module (2) is installed in the receiving cavity, the rotor (3) is installed in the stator module (2), the rotating shaft (4) passes through the rotor (3) and is fixedly connected to the rotor (3), the rotating shaft (4) protrudes from the housing (1), and further comprising a first bearing (5) and a second bearing (6), wherein the first bearing (5) and the second bearing (6) are both sleeved on the rotating shaft (4), and the first bearing (5) and the second bearing (6) are respectively located at both ends of the rotor (3); characterized in that, The first bearing (5) is provided with a first limiting part (51), and the rotor (3) is provided with a second limiting part (31). The first bearing (5) and the rotor (3) can abut against each other through the first limiting part (51) and the second limiting part (31). There is a gap between the remaining positions of the first bearing (5) and the remaining positions of the rotor (3).

2. The stepper motor of claim 1, wherein, The first limiting part (51) is a protrusion and the second limiting part (31) is a groove; or the first limiting part (51) is a groove and the second limiting part (31) is a protrusion.

3. The stepper motor of claim 2, wherein, The first limiting part (51) is arranged around the central axis of the first bearing (5), and the second limiting part (31) is arranged around the central axis of the rotor (3).

4. A stepper motor according to any one of claims 1 to 3, characterised in that, It also includes an elastic element (7), which is sleeved on the outside of the rotating shaft (4). The elastic element (7) is located between the housing (1) and the first bearing (5), or between the first bearing (5) and the rotor (3), or between the rotor (3) and the second bearing (6), or between the second bearing (6) and the stator module (2), or between the second bearing (6) and the housing (1).

5. The stepper motor of claim 4, wherein, Both the first bearing (5) and the second bearing (6) are partially protruding from the housing (1); or both the first bearing (5) and the second bearing (6) are located inside the housing (1).

6. The stepper motor of claim 4, wherein, The rotor (3) has a countersunk hole at the second limiting part (31). The countersunk hole is located inside the second limiting part (31). The elastic element (7) is accommodated in the countersunk hole. One end of the elastic element (7) abuts against the first bearing (5) and the other end abuts against the rotor (3); or the elastic element (7) is sleeved on the outside of the second bearing (6) and one end abuts against the second bearing (6) and the other end abuts against the stator module (2).

7. The stepper motor of claim 1, wherein, The second bearing (6) has a blind hole (61) inside. The bottom of the blind hole (61) is tapered. The shaft (4) is inserted into the blind hole (61) and the end of the shaft (4) abuts against the bottom of the blind hole (61). The end of the shaft (4) is arc-shaped.

8. The stepper motor of claim 7, wherein, The cone angle of the cone structure is 130°±5°.

9. The stepper motor of claim 7, wherein, The cross-sectional area of ​​the blind hole (61) near the top is greater than that near the bottom.

10. The stepper motor of claim 1, wherein, The first bearing (5) is provided with a through hole (52), and the rotating shaft (4) is inserted into the through hole (52). The cross-sectional area of ​​the through hole (52) near the end of the rotor (3) is greater than the cross-sectional area away from the end of the rotor (3).

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