Permanent Magnet Stepper Motor

Abstract

The present invention relates to a permanent magnet stepper motor. The permanent magnet stepper motor includes a motor housing, a stator assembly, a rotor assembly, a rear bottom plate, and a control circuit; the stator assembly is installed on the inner surface of the motor housing, and includes a skeleton and enameled wire; the skeleton includes four sequentially stacked pole tooth inner yoke groups embedded in an engineering plastic base, and each pole tooth inner yoke group is composed of two pole tooth inner yokes arranged opposite to each other; the enameled wire is wound in the wire groove of the skeleton to form a winding group; the control circuit is electrically connected to each winding group through a pin installed on the skeleton, and the two winding groups on the same side are the same phase winding group, and the two winding groups on the other side are the same phase winding group. Under the same operating conditions, the transmission torque of the permanent magnet stepper motor is significantly improved, and the pole teeth can be controlled at a suitable length, and the qualified rate and reliability are also significantly improved.

Description

Technical Field

[0001] The invention relates to a permanent magnet stepping motor. Background Art

[0002] The output torque of permanent magnet stepper motors is generally relatively small due to their structure. The output torque can be increased by adjusting the winding parameters and using the current. If the output torque still does not meet the requirements, the height of the stator frame can be increased (increase the height of the wire slot of the frame) to make the cross-sectional area of ​​the winding group larger, thereby increasing the output torque.

[0003] However, the wider the wire slot is, the longer and narrower the pole teeth of the pole tooth inner yoke will be, so that the increased torque is limited, and it is very easy for the pole teeth to warp in the axial hole of the frame, resulting in more defective products during the frame production process. Summary of the invention

[0004] In view of the above problems, the present invention is proposed to provide a permanent magnet stepper motor that overcomes the above problems or at least partially solves the above problems.

[0005] The permanent magnet stepper motor comprises:

[0006] a motor housing, wherein the motor housing is formed with an opening;

[0007] The stator assembly is installed on the inner surface of the motor housing, and includes a frame and enameled wires; the frame includes four sequentially stacked pole tooth inner yoke groups embedded in an engineering plastic base frame, and each pole tooth inner yoke group is composed of two pole tooth inner yokes arranged opposite to each other; the enameled wires are wound in the wire slots of the frame to form a winding group;

[0008] The rotor assembly is rotatably mounted in the shaft hole formed in the frame, and comprises a magnetic ring and a rotating shaft, wherein the magnetic ring is fixedly connected to the rotating shaft; the rotating shaft is supported by bearings mounted on the motor housing and the rear bottom plate;

[0009] A rear bottom plate covering the opening of the motor housing;

[0010] The control circuit is electrically connected to each winding group through a pin installed on the frame, and makes the two winding groups located on the same side the same phase winding group, and makes the two winding groups located on the other side the same phase winding group.

[0011] Optionally, the skeleton includes a protrusion formed by protruding upward at the front end, and the protrusion is fixedly connected to the inner surface of the motor housing by adhesive.

[0012] Optionally, the protrusion includes an annular protrusion formed by the edge of the shaft hole protruding upward, and a plurality of cylindrical protrusions located outside the annular protrusion.

[0013] Optionally, the circumferential outer wall of the skeleton is fixedly connected to the inner surface of the motor housing by adhesive.

[0014] Optionally, the rear bottom plate includes a boss formed by stamping, and the boss includes a plurality of arcuate stop walls and a plurality of reinforcing walls; the arcuate stop walls are perpendicular to the rear bottom plate body and are distributed in a circular array, and each arcuate stop wall abuts against the inner wall of the axial hole of the skeleton; the reinforcing wall connects two adjacent arcuate stop walls and is located within the imaginary circle where the arcuate stop walls are located, and forms an inclination angle with the rear bottom plate body; a bearing mounting hole is arranged at the center of the boss.

[0015] Optionally, the reinforcing wall is generally in the shape of a U, and includes a first sub-reinforcing wall and a second sub-reinforcing wall. The first sub-reinforcing wall is distributed in a circular array with the center of the imaginary circle where the arc-shaped stop wall is located as the center, and the two ends of the second sub-reinforcing wall are respectively connected to the adjacent end of the first sub-reinforcing wall and the adjacent end of the arc-shaped stop wall.

[0016] Optionally, a limiting groove is formed at an edge of the rear bottom plate, and the limiting groove cooperates with a positioning boss of the frame.

[0017] Optionally, the rotor assembly further includes a support frame, the magnetic ring is sleeved on the support frame, and is fixedly connected to the rotating shaft via the support frame.

[0018] Optionally, a graphite gasket sleeved on the rotating shaft is arranged between the bearing and the support frame.

[0019] Optionally, the bearing is an oil-containing bearing, which is mounted on the motor housing and the rear base plate by riveting.

[0020] In the embodiment of the present invention, the enameled wire wound in the wire slot of the frame forms four winding groups in total, and the control circuit makes the two winding groups on the same side the same phase winding group, and the two winding groups on the other side the same phase winding group. This is equivalent to adding one winding group to each phase line, so that the torque of the motor is significantly improved under the same operating conditions, and the pole teeth can be controlled at an appropriate length, and the qualified rate and reliability are also significantly improved.

[0021] The skeleton is fixedly connected to the inner surface of the motor housing by adhesive, and during the operation of the permanent magnet stepper motor, the skeleton can be prevented from colliding with the motor housing due to radial shaking, thereby reducing resonance noise.

[0022] The arc-shaped stopper wall of the boss of the rear bottom plate abuts against the inner wall of the shaft hole of the frame to ensure the installation accuracy of the rear bottom plate, thereby ensuring the concentricity of the inner holes of the two bearings installed on the motor housing and the boss of the rear bottom plate. In addition, the boss has a large mechanical strength and can withstand axial loads, thereby preventing the boss from breaking or falling off during the operation of the permanent magnet stepper motor, thereby affecting the service life of the permanent magnet stepper motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The included drawings are used to provide a further understanding of the embodiments of the present application, which constitute a part of the specification, are used to illustrate the implementation methods of the present application, and together with the text description, explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0024] Figure 1 It is a structural schematic diagram of an exemplary embodiment of a permanent magnet stepping motor of the present invention;

[0025] Figure 2 for Figure 1 Exploded view of a permanent magnet stepper motor;

[0026] Figure 3 for Figure 1 A cross-sectional view of a permanent magnet stepper motor;

[0027] Figure 4 for Figure 1 Schematic diagram of the structure of the mesoskeleton;

[0028] Figure 5 It is a schematic diagram of the structure of the inner yoke of the pole gear;

[0029] Figure 6 for Figure 1 Schematic diagram of the structure of the middle and rear bottom plate;

[0030] Figure 7 for Figure 6 Middle AA section view;

[0031] Figure 8 for Figure 7 Middle B is an enlarged view;

[0032] Fig. 9 for Figure 7 Enlarged view of middle C.

[0033] Explanation of the accompanying drawings: 1. Motor housing; 2. Rear base plate; 3. Skeleton; 4. Annular boss; 5. Cylindrical boss; 6. Pole teeth; 7. Pin; 8. First winding group; 9. Second winding group; 10. Third winding group; 11. Fourth winding group; 12. PCB board; 13. Magnetic ring; 14. Rotating shaft; 15. Support frame; 16. Bearing; 17. Limiting groove; 18. Positioning boss; 19. Boss; 20. Arc stop wall; 21. Rear base plate body; 22. First sub-reinforcement wall; 23. Second sub-reinforcement wall; 24. Bearing mounting hole; 25. Graphite gasket; 26. Front mounting plate. DETAILED DESCRIPTION

[0034] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but cannot be understood as limiting the present invention. A person of ordinary skill in the art may make various changes, modifications, substitutions and variations to these embodiments without departing from the principles and purpose of the present invention. The scope of the present invention is defined by the claims and their equivalents.

[0035] The terms "center", "longitudinal", "lateral", "length", "up", "down", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like mentioned or may be mentioned in the description of the present invention indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the present invention.

[0036] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In addition, the terms "include", "comprises" and any variations thereof are intended to cover non-exclusive inclusions.

[0037] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] A permanent magnet stepping motor according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0039] See also Figures 1 to 3 , according to an embodiment of the present invention, the permanent magnet stepping motor includes a motor housing 1, a stator assembly, a rotor assembly, a rear base plate 2, and a control circuit.

[0040] Specifically, the motor housing 1 is formed with an opening. The stator assembly is installed at the inner surface of the motor housing 1 , and includes a skeleton 3 and enameled wires. The skeleton 3 is fixedly installed at the inner surface of the motor housing 1 .

[0041] See also Figure 4In this embodiment, the skeleton 3 includes a protrusion formed by the front end protruding upward, and the protrusion is fixedly connected to the inner surface of the motor housing 1 by adhesive, such as high-strength anaerobic adhesive. Specifically, the protrusion includes an annular protrusion 4 formed by the upward protrusion of the edge of the axial hole of the skeleton 3, and a plurality of cylindrical protrusions 5 located on the outside of the annular protrusion 4. After applying the adhesive to the inner surface of the upper end of the motor housing 1, the skeleton 3 is inserted to achieve a fixed connection between the skeleton 3 and the motor housing 1. During the operation of the permanent magnet stepper motor, the fixed connection between the skeleton 3 and the motor housing 1 can prevent the skeleton 3 from colliding with the motor housing 1 due to radial shaking, thereby reducing the resonance noise.

[0042] To further strengthen the fixed connection between the frame 3 and the motor housing 1, the circumferential outer wall of the frame 3 can be fixedly connected to the inner surface of the motor housing 1 by adhesive, such as high-strength anaerobic adhesive. Similarly, after applying the adhesive to the circumferential inner surface of the motor housing 1, inserting the frame 3, the frame 3 can be fixedly connected to the motor housing 1, further reducing the resonance noise.

[0043] The frame 3 comprises four sequentially stacked pole gear inner yoke groups embedded in an engineering plastic base frame, and each pole gear inner yoke group is composed of two pole gear inner yokes arranged opposite to each other. Figure 5 The pole teeth 6 of the pole tooth inner yoke can be formed by stamping, and the number can be 12 or any other suitable number. The pole teeth 6 of the two pole tooth inner yokes of the pole tooth inner yoke group are staggered, that is, the pole teeth 6 of one pole tooth inner yoke extend into the gap between the two pole teeth 6 of the other pole tooth inner yoke.

[0044] Return now Figures 1 to 3 , the enameled wire is wound in the wire slot of the skeleton 3 to form a winding group, that is, the permanent magnet stepper motor includes four winding groups. Of course, the pole tooth inner yoke group is located outside the wire slot. The control circuit is electrically connected to each winding group through the pin 7 installed on the skeleton 3, and makes the two winding groups on the same side the same phase winding group, and the two winding groups on the other side the same phase winding group, even if the first winding group 8 and the second winding group 9 are the same phase winding group, and the third winding group 10 and the fourth winding group 11 are the same phase winding group. It is equivalent to adding a winding group to each phase circuit, so that the torque of the permanent magnet stepper motor is significantly improved under the same operating conditions, and the pole teeth can be controlled at a suitable length, and the qualified rate and reliability are also significantly improved. In this embodiment, the control circuit is engraved on the PCB board 12.

[0045] The rotor assembly is rotatably mounted in the shaft hole formed in the framework 3 and includes a magnetic ring 13 and a rotating shaft 14, and the magnetic ring 13 is fixedly connected to the rotating shaft 14. In this embodiment, the rotor assembly further includes a support frame 15, the magnetic ring 13 is sleeved on the support frame 15, and the two are fixedly bonded by a high-strength anaerobic adhesive, and the support frame 15 is fixedly connected to the rotating shaft 14. The rotating shaft 14 is supported by bearings 16 installed on the motor housing 1 and the rear bottom plate 2.

[0046] The rear bottom plate 2 covers the opening of the motor housing 1 and restricts the rear bottom plate 2 by riveting the opening edge to prevent the rear bottom plate 2 from falling off. In this embodiment, to prevent the rear bottom plate 2 from rotating during the process of riveting the opening edge, a limiting groove 17 is formed at the edge of the rear bottom plate 2, and the limiting groove 17 cooperates with the positioning boss 18 of the framework 3.

[0047] Now refer to Figures 6 to 9 , the rear bottom plate 2 includes a boss 19 formed by stamping, and the boss 19 includes a plurality of arc-shaped stop walls 20 and a plurality of reinforcing walls. In this embodiment, the number of the arc-shaped stop walls 20 is six, and the number of the reinforcing walls is six. It should be understood that the number of the arc-shaped stop walls 20 and the reinforcing walls can also be five, seven, eight, or other suitable numbers.

[0048] The arc-shaped stop walls 20 are perpendicular to the rear bottom plate main body 21 and are distributed in a circular array, and each arc-shaped stop wall 20 abuts against the inner wall of the shaft hole of the framework 3 to ensure the installation accuracy of the rear bottom plate 2. The reinforcing walls connect two adjacent arc-shaped stop walls 20 and are located within the imaginary circle where the arc-shaped stop walls 20 are located. In this embodiment, the reinforcing walls are generally in a U shape and include a first sub-reinforcing wall 22 and a second sub-reinforcing wall 23. The first sub-reinforcing wall 22 is distributed in a circular array with the center of the imaginary circle where the arc-shaped stop walls 20 are located as the center, and the two ends of the second sub-reinforcing wall 23 are respectively connected to the ends of the adjacent first sub-reinforcing wall 22 and the ends of the adjacent arc-shaped stop walls 20. It should be understood that the reinforcing walls can also adopt other suitable shapes and structures.

[0049] The reinforcing walls form an inclination angle with the rear bottom plate main body 21. In this embodiment, the included angle between the reinforcing walls and the rear bottom plate main body 21 is 135°. It should be understood that the included angle between the reinforcing walls and the rear bottom plate main body 21 can also adopt other suitable angles, such as 120°, 140°, 150°, etc. The reinforcing walls can maintain a relatively thick wall thickness, effectively improving the mechanical strength of the boss 19, so as to prevent the boss 19 from cracking and falling off when bearing axial loads.

[0050] Now return to Figure 3The motor housing 1 and the rear bottom plate 2 are provided with a bearing mounting hole 24 at the center of the boss 19, and the rotating shaft 14 is supported by a bearing 16 mounted on the motor housing 1 and the boss 19 of the rear bottom plate 2. In this embodiment, the bearing 16 is an oil-containing bearing, which is mounted on the motor housing 1 and the rear bottom plate 2 by riveting.

[0051] In this embodiment, a graphite gasket 25 sleeved on the rotating shaft 14 is arranged between the bearing 16 and the support frame 15. The permanent magnet stepper motor further comprises a front mounting plate 26, and the front mounting plate 26 is welded to the motor housing 1.

[0052] In the embodiment of the present invention, the enameled wire wound in the wire slot of the frame 3 forms four winding groups in total, and the control circuit makes the two winding groups on the same side the same phase winding group, and the two winding groups on the other side the same phase winding group. This is equivalent to adding a winding group to each phase line, so that the torque of the motor is significantly improved under the same operating conditions, and the pole teeth can be controlled at an appropriate length, and the qualified rate and reliability are also significantly improved.

[0053] The skeleton 3 is fixedly connected to the inner surface of the motor housing 1 by adhesive, which can prevent the skeleton 3 from colliding with the motor housing 1 due to radial shaking during the operation of the permanent magnet stepper motor, thereby reducing resonance noise.

[0054] The arc-shaped stop wall 20 of the boss 19 of the rear bottom plate 2 abuts against the inner wall of the shaft hole of the frame 3, ensuring the installation accuracy of the rear bottom plate 2, thereby ensuring the concentricity of the inner holes of the two bearings 16 installed on the motor housing 1 and the boss 19 of the rear bottom plate 2. In addition, the boss 19 has a large mechanical strength and can withstand axial loads, thereby preventing the boss 19 from breaking or falling off during the operation of the permanent magnet stepper motor, thereby affecting the service life of the permanent magnet stepper motor.

Claims

1. A permanent magnet stepping motor, characterized in that: include: a motor housing, wherein the motor housing is formed with an opening; A stator assembly is installed on the inner surface of the motor housing and includes a skeleton and enameled wires; The frame includes four sequentially stacked pole gear inner yoke groups embedded in an engineering plastic base frame, each pole gear inner yoke group is composed of two pole gear inner yokes arranged opposite to each other; the enameled wire is wound in the wire groove of the frame to form a winding group; The rotor assembly is rotatably mounted in the shaft hole formed in the frame, and comprises a magnetic ring and a rotating shaft, wherein the magnetic ring is fixedly connected to the rotating shaft; the rotating shaft is supported by bearings mounted on the motor housing and the rear bottom plate; A rear bottom plate covering the opening of the motor housing; A control circuit, wherein the control circuit is electrically connected to each winding group through a pin installed on the frame, and makes the two winding groups on the same side the same phase winding group, and makes the two winding groups on the other side the same phase winding group; The rear bottom plate includes a boss formed by stamping, and the boss includes a plurality of arc-shaped stop walls and a plurality of reinforcing walls; the arc-shaped stop walls are perpendicular to the rear bottom plate body and are distributed in a circular array, and each arc-shaped stop wall abuts against the inner wall of the axial hole of the skeleton; the reinforcing wall connects two adjacent arc-shaped stop walls and is located within the imaginary circle where the arc-shaped stop walls are located, and forms an inclination angle with the rear bottom plate body; a bearing mounting hole is arranged at the center of the boss.

2. The permanent magnet stepper motor according to claim 1, characterized in that: The frame includes a protrusion formed by protruding upward at the front end, and the protrusion is fixedly connected to the inner surface of the motor housing by adhesive.

3. The permanent magnet stepper motor according to claim 2, characterized in that: The protrusion comprises an annular protrusion formed by protruding upward from the edge of the shaft hole, and a plurality of cylindrical protrusions located outside the annular protrusion.

4. The permanent magnet stepper motor according to claim 1, characterized in that: The circumferential outer wall of the frame is fixedly connected to the inner surface of the motor housing by adhesive.

5. The permanent magnet stepper motor according to claim 1, characterized in that: The reinforcing wall is generally in the shape of a U, and includes a first sub-reinforcing wall and a second sub-reinforcing wall. The first sub-reinforcing wall is distributed in a circular array with the center of the imaginary circle where the arc stop wall is located as the center, and the two ends of the second sub-reinforcing wall are respectively connected to the adjacent end of the first sub-reinforcing wall and the adjacent end of the arc stop wall.

6. The permanent magnet stepper motor according to claim 1, characterized in that: The rear bottom plate forms a limiting groove at the edge, and the limiting groove cooperates with the positioning boss of the frame.

7. The permanent magnet stepper motor according to claim 1, characterized in that: The rotor assembly also includes a support frame, the magnetic ring is sleeved on the support frame, and is fixedly connected to the rotating shaft through the support frame.

8. The permanent magnet stepper motor according to claim 7, characterized in that: A graphite gasket sleeved on the rotating shaft is arranged between the bearing and the support frame.

9. The permanent magnet stepper motor according to any one of claims 1 to 7, characterized in that: The bearing is an oil-containing bearing, which is installed on the motor housing and the rear bottom plate by riveting.

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