A low-profile motor frame and a stepping motor

Abstract

The utility model relates to the technical field of stepping motor, especially to a low profile motor framework and stepping motor, including coil framework and pole tooth inner yoke, the coil framework is used for winding stator coil, the pole tooth inner yoke is integrally formed in coil framework, the coil framework is equipped with first end plate, second end plate, third end plate and fourth end plate, the pole tooth inner yoke is integrally formed between second end plate and third end plate, make second end plate and third end plate cover respectively in the both sides of pole tooth inner yoke, the axle hole is equipped with in the axle center of coil framework, is used for installing motor rotor, the diameter of axle hole and the interval between first end plate and fourth end plate ratio is greater than 1.3. Finally, the low profile motor framework and stepping motor of the utility model can adapt to limited space, ensure stable performance through optimization design, and adopt reasonable structure to enhance stability, meet the demand of harsh scene.

Description

Technical Field

[0001] This utility model relates to the technical field of stepper motors, and in particular to a low-profile motor frame and a stepper motor. Background Technology

[0002] Permanent magnet synchronous motors are widely used in fields such as automated instrumentation, medical devices, and home appliances due to their significant advantages such as high starting torque and high efficiency. Among them, claw pole motors, as a special type of permanent magnet synchronous motor, employ an axially segmented stator core design, with two stator cores axially engaging to form claw-shaped magnetic poles, further enhancing the motor's operating performance.

[0003] With the increasing trend towards miniaturization and integration of industrial equipment, more stringent requirements are being placed on the height of motors in many space-constrained assembly scenarios, necessitating lower-profile permanent magnet synchronous motors to meet installation needs. However, in existing technologies, reducing the overall height of the motor to fit within limited spaces often leads to a decrease in motor performance.

[0004] Specifically, in the process of reducing the height of traditional motors, the height of the coil frame decreases accordingly, resulting in limited coil winding space and potentially affecting electromagnetic conversion efficiency. Simultaneously, the dimensions of the internal pole teeth structure also change, altering the magnetic flux path and increasing magnetic reluctance, thus reducing electromagnetic torque and compromising the motor's original power output and operational stability. Furthermore, unreasonable shaft hole design and insufficient area of ​​the claw pole pieces within the pole teeth's inner yoke further exacerbate magnetic field dispersion, making it difficult for the motor to maintain its original performance indicators after height reduction, failing to meet the power and stability requirements of specific scenarios. Therefore, how to effectively reduce motor height while ensuring its performance remains unaffected has become a pressing technical challenge in this field. Utility Model Content

[0005] To overcome the shortcomings mentioned above, this utility model aims to provide a technical solution that can solve the above problems.

[0006] This utility model provides a low-profile motor frame, including a coil frame and a pole tooth inner yoke. The coil frame is used to wind stator coils, and the pole tooth inner yoke is integrally formed on the coil frame. The coil frame has a first end plate, a second end plate, a third end plate, and a fourth end plate. The pole tooth inner yoke is integrally formed between the second end plate and the third end plate, so that the second end plate and the third end plate respectively cover both sides of the pole tooth inner yoke. The coil frame has a shaft hole at its center for mounting the motor rotor. The ratio of the diameter of the shaft hole to the distance between the first end plate and the fourth end plate is greater than 1.3.

[0007] Furthermore, the ratio of the diameter of the shaft hole to the distance between the first end plate and the fourth end plate is greater than 1.5.

[0008] Furthermore: the inner yoke of the pole tooth is provided with a first pole plate and a second pole plate that are stacked and abut against each other. The inner circumferential surface of the first pole plate is provided with a first claw pole piece, which is bent toward the first end plate and abuts against the inner wall of the shaft hole; the inner circumferential surface of the second pole plate is provided with a second claw pole piece, which is bent toward the fourth end plate and abuts against the inner wall of the shaft hole.

[0009] Furthermore: a first protrusion is provided on the side of the first electrode plate facing the second electrode plate, and a first locking hole is provided on the second electrode plate corresponding to the first protrusion, so that when the first electrode plate and the second electrode plate are stacked and fixed together, the first protrusion is embedded in the first locking hole to form an interference fit.

[0010] Furthermore, a second protrusion is provided on the side of the second electrode plate facing the first electrode plate, and a second locking hole is provided on the first electrode plate corresponding to the part of the second protrusion, so that when the second electrode plate and the first electrode plate are stacked and fixed together, the second protrusion is embedded in the second locking hole to form an interference fit.

[0011] Furthermore: a connecting post is provided between the second end plate and the third end plate, and a connecting through hole is opened at the part of the inner yoke of the pole tooth corresponding to the connecting post, so that when the inner yoke of the pole tooth is fixed inside the coil frame, the connecting post passes through the connecting through hole.

[0012] Furthermore, the inner wall of the shaft hole of the coil frame is also provided with lateral grooves. Multiple lateral grooves are evenly distributed along the inner wall of the shaft hole and recessed to a certain depth in the direction of the outer periphery of the coil frame to accommodate the claw pole pieces.

[0013] Furthermore: a first winding space is formed between the first end plate and the second end plate of the coil frame for winding the first coil; a second winding space is formed between the third end plate and the fourth end plate for winding the second coil.

[0014] This utility model also provides a stepper motor, including the aforementioned low-profile motor frame, as well as a housing and a cable guard box. A motor coil is wound on the motor frame and installed inside the housing. The cable guard box is installed on the side of the housing for leading out and protecting the ends of the motor coil. A motor rotor is also installed at the shaft hole of the motor frame for power output.

[0015] Furthermore: the end of the cable guard extending into the housing is provided with a limiting groove, and the coil frame is provided with a limiting plate corresponding to the limiting groove, so that the cable guard is fixedly installed on the side of the housing through the cooperation between the limiting plate and the limiting groove.

[0016] Compared with the prior art, the beneficial effects of this utility model are:

[0017] 1. Adaptable to limited installation space: By reducing the height of the coil frame, the overall thickness of the motor frame is significantly reduced, resulting in a lower-profile motor that can perfectly adapt to applications with limited assembly space, especially those with extremely strict height requirements, thus expanding the application range of the motor.

[0018] 2. Ensuring stable motor performance: The design increases the inner diameter of the coil frame shaft hole, which in turn increases the inner diameter of the pole tooth yoke and the area of ​​the pole tooth yoke claw plates. This design optimizes the magnetic flux path, effectively concentrates the magnetic field, reduces magnetic resistance, and ensures that the electromagnetic torque efficiency is not reduced. This allows the motor to maintain its original performance, torque, and power output even when the height is lowered.

[0019] 3. Enhanced Structural Stability: The first and second pole plates of the inner yoke are securely stacked through an interference fit between protrusions and locking holes. The protrusions are evenly distributed, fixing the pole plates from multiple directions and improving the structural strength of the inner yoke itself. Simultaneously, connecting posts are installed between the second and third end plates of the coil frame, passing through the connecting through holes in the inner yoke, further securing it firmly. Even with a reduction in the thickness of the coil frame end plates, the overall structural stability is maintained.

[0020] 4. Optimized production process and structural design: The coil frame is injection molded onto both sides of the inner yoke of the pole teeth using an integrated molding process. During injection molding, the recesses on the back of the protruding pillars and the empty spaces in the retaining holes are filled to form a filler block, further enhancing the pole plate fixing effect. In addition, the lateral grooves on the inner wall of the shaft hole can accommodate the claw pole pieces, avoiding conflict with the motor rotor and ensuring smooth motor operation.

[0021] Therefore, the low-profile motor frame and stepper motor of this utility model can be adapted to limited space, and the optimized design ensures stable performance. The reasonable structure enhances stability and meets the requirements of harsh scenarios.

[0022] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1This is a schematic diagram of the coil frame and housing of this utility model;

[0025] Figure 2 This is a structural schematic diagram of the coil frame and wire protection box of this utility model;

[0026] Figure 3 This is a schematic diagram of the structure of the first end plate and the fourth end plate of this utility model;

[0027] Figure 4 This is a cross-sectional schematic diagram of the inner yoke of the pole teeth and the coil frame of this utility model in a separated state.

[0028] Figure 5 This is a schematic diagram of the structure of the first electrode plate and the second electrode plate of this utility model in the separated state;

[0029] Figure 6 This is a schematic diagram of the structure of the first electrode plate, the second electrode plate, and the coil frame of this utility model in a separated state;

[0030] Figure 7 This is a schematic diagram of the shaft hole of the coil bobbin of this utility model.

[0031] The reference numerals and names in the figure are as follows:

[0032] 10 Coil frame; 11 Limiting plate; 12 Shaft hole; 13 Lateral groove; 14 Lead terminal; 21 First end plate; 22 Second end plate; 23 Third end plate; 24 Fourth end plate; 25 First winding space; 26 Second winding space; 27 Connecting post; 28 Filler block; 30 Pole tooth inner yoke; 31 Connecting through hole; 32 First pole plate; 33 First claw pole piece; 34 First protrusion; 35 Second locking hole; 41 Second pole plate; 42 Second claw pole piece; 43 First locking hole; 44 Second protrusion; 50 Housing; 51 Wire protection box; 52 Limiting groove; 53 Support foot. Detailed Implementation

[0033] The technical solutions in the embodiments of this utility model will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0034] Please see Figures 1 to 7In this embodiment of the present invention, a low-profile motor frame includes a coil frame 10 and a pole tooth inner yoke 30. The coil frame 10 is used to wind stator coils. The pole tooth inner yoke 30 is integrally formed on the coil frame 10. The coil frame 10 is provided with a first end plate 21, a second end plate 22, a third end plate 23, and a fourth end plate 24. The pole tooth inner yoke 30 is integrally formed between the second end plate 22 and the third end plate 23, so that the second end plate 22 and the third end plate 23 respectively cover both sides of the pole tooth inner yoke 30. The coil frame 10 has a shaft hole 12 at its axis for mounting a motor rotor. The ratio of the diameter of the shaft hole 12 to the distance between the first end plate 21 and the fourth end plate 24 is greater than 1.3.

[0035] Specifically, a claw-pole motor is a permanent magnet synchronous motor that uses two stator cores axially joined to form claw-shaped magnetic poles. Its stator cores employ an axially segmented design, with the two sides joining to form claw-shaped magnetic poles. This motor boasts advantages such as high starting torque and high efficiency, and is widely used in automated instruments, medical devices, and home appliances. However, in applications with limited assembly space, lower-profile permanent magnet synchronous motors are required. But ensuring that performance is not compromised after reducing the height of the finished motor is a technical challenge that needs to be addressed.

[0036] This invention reduces the height of the coil frame 10, resulting in a lower coil frame 10, which in turn allows for the assembly of a shorter motor frame, thus creating a lower stepper motor. This design is suitable for applications with limited assembly space, especially those with strict height requirements.

[0037] Secondly, by increasing the inner diameter of the shaft hole 12 of the coil frame 10, the inner diameter of the inner yoke 30 of the pole teeth installed on the inner side wall of the shaft hole 12 is correspondingly increased. At the same time, the area of ​​the claw pole piece of the inner yoke 30 of the pole teeth is also increased, further concentrating the magnetic field, reducing magnetic resistance, and improving electromagnetic torque.

[0038] Therefore, by reducing the thickness of the motor frame and increasing the inner diameter, the performance, torque, and power of the stepper motor remain unchanged, thus providing a low-profile motor frame and a low-profile stepper motor that can be installed normally in a specific assembly space and provide the required power.

[0039] like Figure 3 and Figure 7 As shown, preferably, the ratio of the diameter of the shaft hole 12 to the distance between the first end plate 21 and the fourth end plate 24 is greater than 1.5.

[0040] Specifically, in order to further reduce the height of the coil frame 10 and increase the inner diameter of the shaft hole 12, it is preferable to set the ratio of the diameter of the shaft hole 12 to the distance between the first end plate 21 and the fourth end plate 24 to be greater than 1.5, thereby producing a shorter stepper motor with lower height and unchanged performance. Let the diameter of the shaft hole 12 be d, and the distance between the first end plate 21 and the fourth end plate 24 be L, then the ratio relationship is expressed by the formula: \(\frac{d}{L}>1.5\).

[0041] Secondly, for applications with even more limited assembly space and lower requirements for motor height, the above ratio can be set to greater than 1.7. In some special applications, through optimized design, the above ratio can be set to 1.79, thereby obtaining a lower-profile stepper motor and optimizing its output performance.

[0042] like Figures 3 to 6 As shown, preferably, the inner yoke of the pole tooth 30 is provided with a first pole plate 32 and a second pole plate 41 that are stacked and abut against each other. The inner circumferential surface of the first pole plate 32 is provided with a first claw pole piece 33, which is bent toward the first end plate 21 and abuts against the inner wall of the shaft hole 12. The inner circumferential surface of the second pole plate 41 is provided with a second claw pole piece 42, which is bent toward the fourth end plate 24 and abuts against the inner wall of the shaft hole 12.

[0043] Specifically, multiple claw pole pieces are provided on the inner yoke 30 of the pole teeth. For example, an 8-tooth motor has 8 claw pole pieces evenly distributed along the circumference of the inner yoke 30 of the pole teeth. Since the inner diameter of the shaft hole 12 of the coil frame 10 increases while the number of claw pole pieces remains unchanged, the width of the 8 evenly distributed claw pole pieces extending along the circumference of the shaft hole 12 increases accordingly, thereby further optimizing the magnetic flux path and improving its operating power.

[0044] Secondly, in order to fit the shaft hole 12 with an increased inner diameter, the inner diameter of the inner ring of the pole tooth inner yoke 30 is also increased. In order to fit the corresponding copper wire for winding to form the motor coil, the outer diameter of the inner ring of the pole tooth inner yoke 30 can also be increased, thereby improving the ability of the entire pole tooth inner yoke 30 to conduct magnetic flux and improving the overall performance of the motor.

[0045] like Figures 4 to 6 As shown, preferably, the first electrode plate 32 has a first protrusion 34 on the side facing the second electrode plate 41, and the second electrode plate 41 has a first locking hole 43 at the part corresponding to the first protrusion 34, so that when the first electrode plate 32 and the second electrode plate 41 are stacked and fixed together, the first protrusion 34 is embedded in the first locking hole 43 to form an interference fit.

[0046] Specifically, when the thickness of the end plate of the coil frame 10 is reduced, the fixing strength between the end plate and the inner yoke 30 of the pole teeth may be affected. To strengthen the fixing strength between the two, it is preferable to first strengthen the fixing strength between the two pole plates of the inner yoke 30 of the pole teeth. Therefore, protruding posts are provided on the side of the pole plates, and the protruding posts are then embedded in the locking holes to form an interference fit fixing connection, thereby fixing the first pole plate 32 and the second pole plate 41 together.

[0047] Secondly, to further enhance the fixing strength, two first protrusions 34 can be provided on the first electrode plate 32 and respectively embedded in the two first locking holes 43 opened at the corresponding positions on the second electrode plate 41. The two first protrusions 34 are respectively located at both ends of the same radial direction of the shaft hole 12, which means that the included angle between the two first protrusions 34 is 180° in the circumferential direction of the electrode plate, so that the fixing effect of the two first protrusions 34 on the electrode plate is more balanced.

[0048] like Figures 4 to 6 As shown, preferably, the second electrode plate 41 has a second protrusion 44 on the side facing the first electrode plate 32, and the first electrode plate 32 has a second locking hole 35 at the part corresponding to the second protrusion 44, so that when the second electrode plate 41 and the first electrode plate 32 are stacked and fixed together, the second protrusion 44 is embedded in the second locking hole 35 to form an interference fit.

[0049] Similarly, in order to further enhance the fixed connection strength between the two electrode plates, preferably, a second protrusion 44 is also provided on the second electrode plate 41, which is usually embedded in the second locking hole 35 provided on the first electrode plate 32. The interference fit fixed connection makes the superposition and fixation between the second electrode plate 41 and the first electrode plate 32 more secure.

[0050] Secondly, for the second electrode plate 41, two second protrusions 44 can also be provided, and they are located at both ends of the same radial direction of the shaft hole 12, respectively, to apply a more balanced fixing effect to the electrode plate. Moreover, the two second protrusions 44 and the two first protrusions 34 are spaced at a certain angle in the circumferential direction of the electrode plate, such as 80°, to fix the electrode plate from two different directions, further enhancing the fixing effect between the first electrode plate 32 and the second electrode plate 41.

[0051] like Figures 4 to 6 As shown, preferably, a connecting post 27 is provided between the second end plate 22 and the third end plate 23, and a connecting through hole 31 is provided in the part of the pole tooth inner yoke 30 corresponding to the connecting post 27, so that when the pole tooth inner yoke 30 is fixed inside the coil frame 10, the connecting post 27 passes through the connecting through hole 31.

[0052] Specifically, in order to further reduce the height of the motor, it is preferable to reduce the thickness of the end plate of the coil frame 10. After the end plate thickness is reduced, the fixing force on the inner yoke 30 of the pole tooth is reduced. Therefore, in order to improve the fixing strength of the inner yoke 30 of the pole tooth, it is preferable to set a connecting post 27 between the second end plate 22 and the third end plate 23 that fixes the inner yoke 30 of the pole tooth, and open a connecting through hole 31 at the corresponding part of the inner yoke 30 of the pole tooth. The connecting post 27 is inserted through the connecting through hole 31, thereby firmly fixing the inner yoke 30 of the pole tooth between the second end plate 22 and the third end plate 23.

[0053] Secondly, since the coil frame 10 is directly injection molded onto both sides of the inner yoke 30 using an integral molding process, in the specific manufacturing process, the first electrode plate 32 and the second electrode plate 41 can be stamped to form corresponding claw electrode pieces, connecting through holes 31, protrusions, and locking holes. Then, the first electrode plate 32 and the second electrode plate 41 are stacked and fixed by the interference fit between the protrusions and the locking holes. Then, the stacked and fixed inner yoke 30 is placed in the injection cavity of the injection mold, and the inner yoke 30 is injection molded to form the coil frame 10 with the inner yoke 30, so that the inner yoke 30 is firmly fixed inside the relatively thin coil frame 10.

[0054] In addition, since the stamping of the protrusion will create a depression on its back, and the protrusion will also create some empty space in the card hole after being inserted into the card hole, the depression and empty space can be filled by injection molding during the injection molding process to form a filling block 28, which further enhances the fixation of the electrode plate.

[0055] like Figure 4 As shown, preferably, the inner wall of the shaft hole 12 of the coil frame 10 is also provided with a lateral groove 13. Multiple lateral grooves 13 are evenly distributed along the inner wall of the shaft hole 12 and recessed to a certain depth in the direction of the outer periphery of the coil frame 10 to accommodate the claw pole piece.

[0056] Specifically, in order to accommodate the claw pole pieces and ensure that the claw pole pieces are tightly attached to the inner wall of the shaft hole 12 without obstructing the operation of the motor rotor, a lateral groove 13 can be provided on the inner wall of the shaft hole 12. This groove allows the claw pole pieces to be positioned within the lateral groove 13, thus achieving an installation method that embeds them into the outer wall of the shaft hole 12 and avoids conflict with the motor rotor.

[0057] like Figure 3 and Figure 6 As shown, preferably, a first winding space 25 is formed between the first end plate 21 and the second end plate 22 of the coil frame 10 for winding the first coil; a second winding space 26 is formed between the third end plate 23 and the fourth end plate 24 for winding the second coil.

[0058] Specifically, in order for the motor rotor to rotate, stator coil windings need to be wound on the coil frame 10. Correspondingly, two winding spaces can be formed on the coil frame 10, thereby forming two windings for winding the corresponding coils.

[0059] like Figures 1 to 3 As shown, a preferred stepper motor includes the aforementioned motor frame, a housing 50, and a cable guard box 51. A motor coil (not shown in the figure) is wound on the motor frame and installed inside the housing 50. The cable guard box 51 is installed on the side of the housing 50 and is used to lead out and protect the ends of the motor coil. A motor rotor (not shown in the figure) is also installed at the shaft hole 12 of the motor frame for power output.

[0060] Specifically, in order to assemble a stepper motor, a motor coil needs to be wound onto the motor frame and installed inside the housing 50. Then, the motor rotor is installed at the bottom of the housing 50, making it rotatably connected to the bottom of the housing 50 and rotating at the position of the shaft hole 12. Power is then output through the output gear (not shown in the figure). The motor coil, motor rotor, and output gear are all existing components in the prior art and can be assembled and produced using existing technology, so they will not be described in detail here.

[0061] like Figure 2 As shown, preferably, the end of the cable guard box 51 extending into the housing 50 is provided with a limiting groove 52, and the coil frame 10 is provided with a limiting plate 11 corresponding to the limiting groove 52, so that the cable guard box 51 is fixedly installed on the side of the housing 50 through the cooperation between the limiting plate 11 and the limiting groove 52.

[0062] Specifically, after the coil winding is completed on the coil frame 10, the cable end needs to be led out of the motor so that it can be connected to the external circuit and operate normally. Therefore, a lead terminal 14 can be provided on the coil frame 10 corresponding to the cable protection box 51 for installing the cable end, and the lead terminal 14 is embedded in the cable protection box 51 so that the cable protection box 51 protects and leads out the cable end.

[0063] To secure the wire protection box 51, a limiting groove 52 can be provided at one end of the wire protection box 51 that extends into the housing 50. The limiting plate 11 provided on the coil frame 10 can be inserted into the limiting groove 52 to form a snap-fit ​​connection with the wire protection box 51, thereby allowing the wire protection box 51 to be installed on the coil frame 10.

[0064] Secondly, the part of the cable protection box 51 that abuts against the housing 50 is also provided with a support foot 53, so that the part of the cable protection box 51 that is outside the housing 50 can abut against the outer wall of the housing 50 through the support foot 53, thereby cooperating with the snap-fit ​​connection inside the housing 50, so that the cable protection box 51 is stably installed on the side of the housing 50.

[0065] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention.

Claims

1. A low-profile motor frame, characterized in that, The device includes a coil frame (10) and a pole tooth inner yoke (30). The coil frame (10) is used to wind the stator coil. The pole tooth inner yoke (30) is integrally formed on the coil frame (10). The coil frame (10) is provided with a first end plate (21), a second end plate (22), a third end plate (23), and a fourth end plate (24). The pole tooth inner yoke (30) is integrally formed between the second end plate (22) and the third end plate (23), so that the second end plate (22) and the third end plate (23) respectively cover the two sides of the pole tooth inner yoke (30). The coil frame (10) has a shaft hole (12) at its axis for mounting the motor rotor. The ratio of the diameter of the shaft hole (12) to the distance between the first end plate (21) and the fourth end plate (24) is greater than 1.

3.

2. The low-profile motor frame according to claim 1, characterized in that, The ratio of the diameter of the shaft hole (12) to the distance between the first end plate (21) and the fourth end plate (24) is greater than 1.

5.

3. The low-profile motor frame according to claim 1, characterized in that, The inner yoke of the pole tooth (30) is provided with a first pole plate (32) and a second pole plate (41) that are stacked and abut against each other. The inner circumferential surface of the first pole plate (32) is provided with a first claw pole piece (33). The first claw pole piece (33) is bent toward the first end plate (21) and abuts against the inner wall of the shaft hole (12). The inner circumferential surface of the second pole plate (41) is provided with a second claw pole piece (42). The second claw pole piece (42) is bent toward the fourth end plate (24) and abuts against the inner wall of the shaft hole (12).

4. A low-profile motor frame according to claim 3, characterized in that, The first electrode plate (32) has a first protrusion (34) on the side facing the second electrode plate (41), and the second electrode plate (41) has a first locking hole (43) at the part corresponding to the first protrusion (34). When the first electrode plate (32) and the second electrode plate (41) are stacked and fixed together, the first protrusion (34) is embedded in the first locking hole (43) to form an interference fit.

5. A low-profile motor frame according to claim 3, characterized in that, The second electrode plate (41) has a second protrusion (44) on the side facing the first electrode plate (32). The first electrode plate (32) has a second locking hole (35) corresponding to the second protrusion (44). When the second electrode plate (41) and the first electrode plate (32) are stacked and fixed together, the second protrusion (44) is embedded in the second locking hole (35) to form an interference fit.

6. A low-profile motor frame according to claim 1, characterized in that, A connecting post (27) is provided between the second end plate (22) and the third end plate (23). A connecting through hole (31) is provided on the inner yoke of the pole tooth (30) corresponding to the connecting post (27). When the inner yoke of the pole tooth (30) is fixed inside the coil frame (10), the connecting post (27) passes through the connecting through hole (31).

7. A low-profile motor frame according to claim 3, characterized in that, The inner wall of the shaft hole (12) of the coil frame (10) is also provided with a lateral groove (13). Multiple lateral grooves (13) are evenly distributed along the inner wall of the shaft hole (12) and recessed to a certain depth in the direction of the outer periphery of the coil frame (10) to accommodate the claw pole piece.

8. A low-profile motor frame according to claim 1, characterized in that, A first winding space (25) is formed between the first end plate (21) and the second end plate (22) of the coil frame (10) for winding the first coil; a second winding space (26) is formed between the third end plate (23) and the fourth end plate (24) for winding the second coil.

9. A stepper motor, characterized in that, The invention includes a low-profile motor frame according to any one of claims 1-8, and further includes a housing (50) and a wire protection box (51). A motor coil is wound on the motor frame and installed inside the housing (50). The wire protection box (51) is installed on the side of the housing (50) for leading out and protecting the end of the motor coil. A motor rotor is also installed at the shaft hole (12) of the motor frame for power output.

10. A stepper motor according to claim 9, characterized in that, The wire protection box (51) has a limiting groove (52) at one end extending into the housing (50). The coil frame (10) has a limiting plate (11) corresponding to the limiting groove (52), so that the wire protection box (51) is fixedly installed on the side of the housing (50) through the cooperation between the limiting plate (11) and the limiting groove (52).

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