Motor

Abstract

The utility model discloses a motor and relates to the motor field, the motor comprises a casing, a stator punching sheet and a stator yoke portion, the casing is internally provided with an accommodating cavity; the stator punching sheet comprises a plurality of stator shoe parts and stator tooth parts which are circumferentially arranged in a surrounding manner, and two adjacent stator tooth parts are connected through the stator shoe parts; the stator yoke part is annular, the outer wall of the stator yoke part is connected in the accommodating cavity, and the stator tooth part is in interference connection with the inner wall of the stator yoke part; the material of the stator yoke part is different from the materials of the casing and the stator punching sheet, and the inner wall of the stator yoke part is formed through machining. The stator yoke part is formed by machining steel or alloy materials with good magnetic conductivity, and the stator tooth part is formed by punching materials such as silicon steel sheets. Therefore, when the stator tooth part is in interference fit with the stator yoke part, the friction force is obviously reduced, the deformation of the stator shoe part can be reduced, and the cogging torque and the counter potential waveform distortion rate are further ensured to be within a reasonable range.

Description

Technical Field

[0001] The utility model relates to the field of motors, in particular to a motor. Background Art

[0002] Compared with the traditional block-jointed stator, the stator structure with separated teeth and yoke has a higher slot fill rate and smaller cogging torque. The separation of teeth and yoke is to stamp the stator teeth and stator yoke separately, and then press the stator teeth and stator yoke together through tooling equipment. In order to ensure the connection reliability between the stator teeth and the stator yoke, the stator teeth and the stator yoke are connected by interference fit. In order to reduce magnetic leakage and reduce the cogging torque, the stator boot connection position of the stator teeth is designed to be narrow, which is generally around 0.3mm due to the limitations of the stamping process. During the crimping process, the friction between the stator teeth and the stator yoke silicon steel sheets gradually increases with the increase of the pressing depth, which will cause the stator teeth to warp. The connection of the stator boot is thin, which will cause the inner diameter of the stator to deform, resulting in a deviation between the air gap shape and the design value, increasing the cogging torque and increasing the back-EMF waveform distortion rate. Utility Model Content

[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model provides a motor that can reduce the friction between the stator teeth and the stator yoke during the pressing process.

[0004] According to an embodiment of the utility model, the motor comprises a casing, a stator punching sheet and a stator yoke, wherein an accommodating cavity is arranged inside the casing; a plurality of stator punching sheets are axially stacked, and the stator punching sheets comprise a plurality of stator boots and stator teeth arranged circumferentially, and two adjacent stator teeth are connected by the stator boots; the stator yoke is arranged in a ring shape, and the outer wall of the stator yoke is connected to the accommodating cavity, and the stator teeth are interference connected to the inner wall of the stator yoke; the material of the stator yoke is different from the material of the casing and the stator punching sheet, and the inner wall of the stator yoke is formed by machining, and the stator yoke is separately formed and then installed in the casing, or the stator yoke is integrally cast with the casing and then formed by machining.

[0005] The motor according to the embodiment of the utility model has at least the following beneficial effects: the stator yoke is formed by machining with steel or alloy material with good magnetic conductivity by using different material combinations, and the stator teeth are formed by stamping with silicon steel sheets and other materials. When the stator teeth are interference-fitted to the stator yoke, the friction force is significantly reduced, the deformation of the stator boot can be reduced, and the tooth slot torque and the back-EMF waveform distortion rate are further guaranteed to be within a reasonable range.

[0006] According to some embodiments of the utility model, the stator yoke is composed of a plurality of blocks, the plurality of blocks are arranged along the axial direction of the stator yoke, and an insulating layer is provided between two adjacent blocks, and along the axial direction of the stator yoke, the width of the block is greater than the thickness of the stator punching sheet.

[0007] According to some embodiments of the present invention, the stator yoke is composed of a plurality of blocks, and the plurality of blocks are arranged along the circumference of the stator yoke.

[0008] According to some embodiments of the utility model, the stator yoke is composed of a block, and the stator yoke is provided with a plurality of annular dividing grooves, and the annular dividing grooves are located on the inner wall of the stator yoke, and each of the annular dividing grooves divides the inner wall surface of the stator yoke into two contact surfaces distributed at intervals, and the contact surface is interference connected with the stator tooth portion, and along the axial direction of the stator yoke, the width of the contact surface is greater than the thickness of the stator punching sheet.

[0009] According to some embodiments of the present invention, the inner wall surface of the stator yoke is provided with a plurality of recesses, the plurality of recesses are distributed at intervals along the circumference of the stator yoke, and the recesses correspond one-to-one to the positions of the stator teeth.

[0010] According to some embodiments of the present invention, the recess is formed by cutting.

[0011] According to some embodiments of the present invention, a limiting portion is provided on an inner wall of the accommodating cavity, and the limiting portion positions the stator yoke along the axial direction of the accommodating cavity.

[0012] According to some embodiments of the present utility model, the casing includes a shell and a base, the shell and the base are detachably connected, and the accommodating cavity is provided in the shell.

[0013] According to some embodiments of the present invention, the power of the motor is less than or equal to 750 W, and the frequency of the motor is 20 Hz to 200 Hz.

[0014] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention is further described below with reference to the accompanying drawings and embodiments, wherein:

[0016] Figure 1 is a schematic diagram of a gear yoke separation structure in the related art;

[0017] Figure 2 An exploded view of a motor according to an embodiment of the present utility model;

[0018] Figure 3 for Figure 2 A schematic diagram of a stator yoke portion of a stator is shown;

[0019] Figure 4 for Figure 3 An enlarged view of point A is shown;

[0020] Figure 5 for Figure 2 A schematic diagram of a stator tooth portion of a stator is shown;

[0021] Figure 6 for Figure 2 The assembly diagram of the stator is shown;

[0022] Figure 7 for Figure 2 A schematic diagram of a motor is shown;

[0023] Figure 8 A schematic diagram of a stator yoke and a housing according to another embodiment of the present invention;

[0024] Fig. 9 A schematic diagram of a stator yoke and a housing according to another embodiment of the present invention;

[0025] Fig.10 A schematic diagram of a stator yoke and a housing according to another embodiment of the present invention;

[0026] Fig.11 A schematic diagram of a stator yoke and a housing according to another embodiment of the present invention;

[0027] Fig.12 A schematic diagram of a stator yoke of another embodiment of the utility model;

[0028] Fig.13 A schematic diagram of a stator yoke of another embodiment of the utility model;

[0029] Fig.14 This is a comparison diagram of back electromotive force of stator yokes with different structures and materials;

[0030] Fig.15 This is a comparison chart of the output electromagnetic torque of stator yokes with different structures and materials;

[0031] Fig.16 A manufacturing process flow chart of an embodiment of the motor of the utility model;

[0032] Fig.17 This is a manufacturing process flow chart of another embodiment of the motor of the utility model.

[0033] Reference numerals:

[0034] 101. stator yoke; 102. stator teeth;

[0035] 201, stator punching sheet; 202, stator yoke; 203, block; 204, mounting hole; 205, housing; 206, accommodating cavity; 207, concave position; 208, convex position;

[0036] 501, stator shoe; 502, stator tooth;

[0037] 1001. Shell;

[0038] 1101, gap;

[0039] 1201. Annular dividing groove; 1202. Contact surface. DETAILED DESCRIPTION

[0040] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0041] In the description of the present invention, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are 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 device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0042] In the description of the present utility model, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0043] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0044] In the related art, the stator core in the motor is usually prepared by blanking silicon steel sheets as a whole, that is, the stator structure is generally integrated with a tooth yoke. This structure is to make multiple stator punchings separately, and then assemble them together by splicing to meet the technical needs of the motor. In the manufacturing process, multiple stator punchings are usually fixed together by welding, buckle riveting, buckle point riveting, etc. In another structural form, the stator core is assembled by block cores, that is, the stator core includes multiple block cores matched along the circumferential direction, each block core is composed of stator teeth, stator yokes and pole shoes, and the gaps between two adjacent block cores form stator slots, and the stator coils are wound on the stator teeth through the stator slots. The block stator core has the advantages of high material utilization and material saving during manufacturing, but because the notch size between the stator teeth after assembly is small, the block stator core can only be wound separately by winding the single block core in an external winding manner, and then the single block core is spliced. Moreover, such a stator is difficult to wind, has a low slot fill rate, and has long ends, resulting in low power density and large magnetic leakage at the stator teeth.

[0045] With the pursuit of high power density and high positioning accuracy of servo motors, many products have begun to consider the stator structure with separated tooth yoke to make the product have a higher slot fill rate and smaller cogging torque. The stator structure with separated tooth yoke has a higher slot fill rate, mainly because this structure can reduce the size of the tooth slot and increase the depth of the tooth slot, thereby improving the slot fill rate. In addition, this structure can also reduce magnetic leakage and improve the efficiency and working stability of the motor. Cogging torque is the torque generated by the interaction between the permanent magnet and the iron core on the non-same side when the permanent magnet motor winding is not energized. It is caused by the tangential component of the interaction force between the permanent magnet and the armature tooth. The cogging torque will cause the motor to vibrate and make noise, and the speed will fluctuate, so that the motor cannot run smoothly, affecting the performance of the motor.

[0046] Reference Figure 1 As shown, the stator is composed of a stator yoke 101 and stator teeth 102, which are connected in a certain way. In the stator structure with separated yoke, the stator yoke 101 is usually in a circular ring shape, which is used to support and fix the stator teeth 102. The stator teeth 102 have a plurality of protruding teeth for interacting with the rotor of the motor to generate electromagnetic torque. The stator structure with separated yoke has a smaller cogging torque, mainly because this structure can reduce the size of the tooth slot, thereby reducing the cogging torque. In addition, this structure can also improve the air gap magnetic field distribution, reduce magnetic resistance, and further reduce the cogging torque. Specifically, the stator structure with separated yoke can make the permanent magnet closer to the air gap, thereby reducing magnetic resistance and cogging torque. At the same time, this structure can also reduce the volume of the permanent magnet, reduce costs, and improve the efficiency and working stability of the motor.

[0047] Compared with the traditional block stator structure, the tooth-yoke separated stator structure has other advantages. First, since the stator yoke 101 and the stator teeth 102 are separated, they can be processed and manufactured separately, thereby reducing the manufacturing difficulty and cost, and can effectively solve the problems of complex assembly process and difficulty in ensuring the roundness of the whole circle in the traditional block stator structure. Secondly, this structure can effectively improve the magnetic circuit performance of the motor, thereby improving the efficiency and performance of the motor. In addition, since the stator teeth 102 in the tooth-yoke separated stator structure can be designed and adjusted more flexibly, it can better meet the needs of different motors.

[0048] Reference Figure 1 As shown, in the tooth yoke separation structure in the related art, the stator yoke 101 and the stator teeth 102 are formed by punching and laminating multiple cold-rolled silicon steel sheets, and then the stator teeth 102 are crimped to the stator yoke 101 by tooling equipment. In order to reduce magnetic leakage and reduce the tooth slot torque, the stator boot 501 connection position of the stator tooth 102 is designed to be narrow. Limited by the stamping process, the size of the stator boot 501 connection position is generally around 0.3 mm. During the pressing process, the inter-sheet friction between the stator tooth 102 and the stator yoke 101 silicon steel sheet gradually increases with the increase of the pressing depth, which will cause the stator tooth 102 to warp. The stator tooth 102 boot connection is thin, which causes the inner diameter of the stator to deform, resulting in a deviation between the air gap shape and the design value, increasing the tooth slot torque, and increasing the back EMF waveform distortion rate. In the actual production process, some manufacturers will use drum stamping of the stator yoke 101 and the stator teeth 102 to solve the problem of warping of the stator teeth 102 during assembly, which will inevitably use more complex stamping dies and generate higher production costs.

[0049] Reference Figure 2 As shown, it can be understood that the stator of the first aspect of the utility model embodiment includes a stator punching sheet 201 and a stator yoke 202, and the stator punching sheet 201 and the stator yoke 202 can be separated from each other. By setting the stator yoke 202 and the stator punching sheet 201 as a separable assembly structure, the stator yoke 202 and the stator punching sheet 201 can be assembled after the stator winding is completed. On the one hand, it can simplify the winding process of the stator winding and improve the convenience of stator winding. On the other hand, it is also conducive to improving the filling rate of the winding slot, thereby improving the performance of the motor prepared by the stator core.

[0050] Reference Figure 2As shown, it can be understood that the stator yoke 202 is composed of a block 203, that is, the stator yoke 202 is made of a complete material in an integrated manner, which is different from the related art in which multiple cold-rolled silicon steel sheets are punched and stacked. The material of the stator yoke 202 is different from the material of the stator punching 201. The material of the stator yoke 202 is more suitable for machining and has good magnetic conductivity. For example, the material of the stator yoke 202 can be steel or alloy material. The stator yoke 202 is annular as a whole, that is, the stator yoke 202 is provided with a mounting hole 204, and the stator punching 201 is located in the mounting hole 204 and is interference-connected with the stator yoke 202. The inner wall surface of the stator yoke 202 in the mounting hole 204 is a complete curved surface. According to the processing requirements of the stator yoke 202, the inner wall surface of the mounting hole 204 is a relatively smooth curved surface. The stator punching 201 encounters less resistance during the interference fit into the mounting hole 204, making the assembly process smoother. Figure 1 The stator yoke 101 shown, which is formed by punching and laminating multiple cold-rolled silicon steel sheets, will reduce the resistance encountered by the stator punching sheet 201 during the assembly process, thereby reducing the deformation of the stator punching sheet 201, ensuring the installation accuracy and reducing the influence of the installation process on the tooth slot torque and the back-EMF waveform distortion rate.

[0051] Reference Figure 2 As shown, it can be understood that a plurality of stator punching sheets 201 are stacked in the axial direction, and each stator punching sheet 201 is designed as an integrated structure. Figure 5 As shown, the stator punching sheet 201 is in an annular shape as a whole, and the stator punching sheet 201 includes a plurality of stator boots 501 and stator teeth 502 arranged circumferentially, and two adjacent stator teeth 502 are connected by the stator boots 501, that is, all stator teeth 502 are spaced and distributed on the outer wall of the stator boots 501, and a stator slot is formed between two adjacent stator teeth 502 and the stator boots 501. Exemplarily, there are 12 stator teeth 502 in the circumferential direction of the stator punching sheet 201, and the stator teeth 502 are connected to form a whole through the stator boots 501, and the outside of the stator punching sheet 201 is interference-connected with the inner wall of the mounting hole 204 of the stator yoke 202, that is, the stator teeth 502 are interference-connected with the inner wall of the stator yoke 202. Enameled wires are nested on the stator teeth 502, and the ends of the enameled wires are welded to the circuit board at the end of the motor. The enameled wires on each stator tooth 502 are connected through internal wiring of the circuit board, and the enameled wires are wound on the stator teeth 502. Then the ends of the wires are welded to the circuit board. The enameled wires can also be compressed during the winding process, thereby improving the slot fill rate.

[0052] Laminated cores can reduce "eddy current losses". Eddy current losses are caused by energy loss caused by the induced current in the conductor when the conductor moves in a non-uniform magnetic field or is in a magnetic field that changes with time. The closed loops of current lines formed inside the conductor are called eddy currents. When the motor is working, there is an alternating current in the coil, and the magnetic flux it generates is also alternating. This changing magnetic flux generates an induced current in the core. The induced current generated in the core circulates in a plane perpendicular to the direction of the magnetic flux, so it is called eddy current. Eddy current loss generates heat and reduces the efficiency of electronic equipment, especially in high-frequency circuits. Excessive eddy current loss may cause the temperature of the component to rise, which may cause component damage. In addition, excessive eddy current loss may also affect the stability of the system. For example, in a motor, eddy current loss may cause problems such as reduced motor efficiency, increased temperature rise, noise and vibration. In one embodiment, the stator sheet 201 is made of silicon steel sheets, so that the eddy current passes through a smaller cross section in a narrow and long loop to increase the resistance on the eddy current path; at the same time, the silicon in the silicon steel increases the resistivity of the material, which also plays a role in reducing the eddy current. In contrast, the one-piece stator sheet 201 has a lower resistivity and is prone to eddy current, resulting in greater eddy current losses.

[0053] To sum up, the stator of the embodiment of the utility model, the stator yoke 202 is made of a complete block 203, the stator punching 201 can play a role in reducing eddy currents, and the stator yoke 202 can convert the friction between the silicon steel sheets and the silicon steel sheets before the improvement into the friction between the silicon steel sheets and the machined surface of the stator yoke 202. The reduction in friction reduces the deformation of the stator shoe 501 during the process of pressing the stator punching 201 into the stator yoke 202, thereby ensuring the installation accuracy and reducing the influence of the installation process on the tooth slot torque and the back-electromotive force waveform distortion rate.

[0054] Reference Figure 2 As shown, it can be understood that the motor of the second aspect embodiment of the utility model includes a housing 205 and a stator of the first aspect embodiment of the utility model. The housing 205 is provided with a containing cavity 206, and the stator is arranged in the containing cavity 206. The housing 205 is usually made of aluminum, cast iron or steel plate, and has good mechanical strength and heat resistance, that is, the material of the stator yoke 202 is different from the material of the housing 205. The housing 205 not only supports the stator, but also is responsible for transferring the heat generated by the motor to the outside to keep the temperature of the motor stable. The connection method between the stator and the housing 205 may vary depending on the motor type and design requirements. Common connection methods include interference fit, key connection, screw fixing, etc. Interference fit is a common connection method, which is achieved by pressing the stator into the housing 205 and using the interference between the two to achieve a tight fit. For example, referring to Figure 6 As shown, first press the stator yoke 202 into the stator punching 201, refer to Figure 7As shown, the stator sheet 201 and the stator yoke 202 are pressed into the housing 205. The key connection is suitable for larger motors, and the torque and moment are transmitted through the key. The screw fixation is to fix the stator and the housing 205 together with screws, which has higher stability and reliability. Figure 1 The stator yoke 101 shown is formed by stamping and laminating multiple cold-rolled silicon steel sheets. The gap between the two silicon steel sheets is not in contact with the housing 205. The stator yoke 202 of the embodiment of the utility model reduces the gap between the two silicon steel sheets, so that the contact with the housing 205 is more sufficient, which is more conducive to heat dissipation. At the same time, compared with the stamping parts, the stator yoke 202 of the embodiment of the utility model can also reduce the vibration of the motor by increasing the thickness.

[0055] Reference Figures 2 to 4 As shown, it can be understood that the stator yoke 202 is provided with a plurality of recesses 207, and the plurality of recesses 207 are arranged on the inner wall surface of the mounting hole 204, so as to form a concave-convex structure on the inner wall surface of the mounting hole 204, and the plurality of recesses 207 are distributed at intervals along the circumference of the mounting hole 204. In other words, the inner wall surface of the mounting hole 204 is provided with a plurality of recesses 207 and a plurality of convex positions 208, and the recesses 207 and the convex positions 208 are arranged at intervals, and each convex position 208 is located between two adjacent recesses 207, and the recesses 207 correspond to the positions of the stator teeth 502 one by one. While the recesses 207 cooperate with the stator punching sheet 201, as much space as possible is provided to place the enameled wire. The recess 207 is set as a U-shaped structure, and the end of the stator tooth 502 is accommodated in the recess 207. The recess 207 can position the stator tooth 502. When the stator tooth 502 has a rotation tendency, the recess 207 can also play a limiting role, thereby solving the problem of relative rolling between the stator punching sheet 201 and the stator yoke 202.

[0056] It can be understood that the inner wall of the accommodating cavity 206 is provided with a limiting portion, and when the stator yoke 202 is installed in the accommodating cavity 206, since the limiting portion protrudes from the inner wall of the accommodating cavity 206, after the stator yoke 202 contacts the limiting portion, it cannot continue to move along the axial direction of the accommodating cavity 206. In other words, the limiting portion positions the stator yoke 202 along the axial direction of the accommodating cavity 206, thereby controlling the assembly depth of the stator.

[0057] Reference Figure 8The schematic diagram of the stator yoke 202 and the housing 205 shown in FIG. 1 can be understood that in another embodiment, the stator yoke 202 and the housing 205 are cast in one piece. Through the one-piece casting, the stator yoke 202 and the housing 205 form a whole without a connecting part, thereby ensuring the integrity and stability of the structure. One-piece casting avoids the connection and assembly process between the stator yoke 202 and the housing 205, simplifies the manufacturing process, and reduces the manufacturing cost. Since the stator yoke 202 and the housing 205 are a whole without a connecting gap 1101, their mechanical strength is improved and they can better withstand external loads and internal pressures. The housing 205 is an important channel for heat dissipation of the motor. The one-piece cast stator yoke 202 and the housing 205 can work better together, improve the heat dissipation efficiency, and help the motor to run stably under high load conditions. Since the stator yoke 202 and the housing 205 have no connecting parts, the possibility of failure caused by loose or loose connections is reduced, and the reliability and stability of the motor are improved. In summary, integrally casting the stator yoke 202 and the housing 205 can bring advantages such as structural integrity, simplified manufacturing process, enhanced mechanical strength, improved heat dissipation efficiency, and reduced possibility of failure. The plurality of concave positions 207 and the plurality of convex positions 208 provided on the stator yoke 202 can be obtained by cutting with a broach or a boring tool.

[0058] Reference Fig. 9 The schematic diagram of the stator yoke 202 and the housing 205 shown in the figure, it can be understood that in another embodiment, the multiple concave positions 207 and the multiple convex positions 208 provided on the stator yoke 202 are cancelled. At this time, when assembling the motor, the stator punching 201 is pressed into the mounting hole 204 of the stator yoke 202, and the stator punching 201 is connected with the stator yoke 202 by interference fit, so that the stator punching 201 is fixed.

[0059] Reference Fig.10 As shown, it can be understood that in another embodiment, the housing 205 is a split structure, that is, the housing 205 includes a shell 1001 and a base, the shell 1001 and the base are detachably connected, and the accommodating cavity 206 is provided in the shell 1001. When assembling the motor, the stator yoke 202 is first pressed into the stator punching 201, and then the stator punching 201 and the stator yoke 202 are pressed into the shell 1001 together, and the base is finally connected to the shell 1001. When the stator needs to be repaired, the base can be removed, and then the stator punching 201 and the stator yoke 202 can be removed. Compared with the integrated housing 205, the split housing 205 is more convenient for repair.

[0060] At the same time, due to the use of the stator yoke 202 of the embodiment of the utility model, compared with Figure 1The stator yoke 101 shown is formed by punching and laminating multiple cold-rolled silicon steel sheets, which will increase the eddy current loss of the stator yoke part 202. In order to reduce the influence of eddy current loss on the motor, the embodiment of the utility model adopts the following improvement scheme.

[0061] Reference Fig.11 As shown, it can be understood that in another embodiment, the stator yoke 202 is composed of a plurality of independent blocks 203, and along the axial direction of the mounting hole 204, the thickness of each block 203 is greater than the thickness of each stator punching sheet 201, so that when the stator punching sheet 201 moves in the mounting hole 204, the stator punching sheet 201 mainly moves along the processing surface of the block 203, and the number of gaps 1101 between the two blocks 203 is small, so that the resistance of the stator punching sheet 201 during the assembly process is reduced, and then the deformation of the stator punching sheet 201 is reduced, so that the installation accuracy is guaranteed, and the influence of the installation process on the cogging torque and the back electromotive force waveform distortion rate is reduced. And after the stator yoke 202 is installed in the accommodating cavity 206, the plurality of blocks 203 are arranged at intervals along the axial direction of the accommodating cavity 206, and an insulating layer is provided between two adjacent blocks 203. The function of the insulating layer is mainly to prevent the current from being lost directly through the block 203 and to improve the magnetic permeability of the block 203. Since the resistivity of the insulating layer is large, the relative current density is small. Therefore, when the insulating layer is separated by the block 203, the current is forced to flow around the surface of the block 203. Since the amount of current loss is reduced, the core loss is reduced and the noise becomes smaller. In addition, the insulating layer can also protect the surface of the block 203 from the influence of arcs and sparks, thereby increasing its service life.

[0062] Reference Fig.12As shown, it can be understood that, in another embodiment, the stator yoke 202 is composed of a complete block 203, and the block 203 is provided with a plurality of annular dividing grooves 1201, and the annular dividing grooves 1201 are located on the inner wall of the mounting hole 204, and the annular dividing grooves 1201 are arranged around the circumference of the mounting hole 204, and each annular dividing groove 1201 divides the inner wall surface of the mounting hole 204 into two contact surfaces 1202 distributed at intervals. Along the axial direction of the mounting hole 204, the width of the contact surface 1202 is greater than the thickness of the stator punching 201. When the stator punching 201 is assembled into the mounting hole 204, the contact surface 1202 is connected with the stator punching 201 by interference. When the stator punching 201 moves in the mounting hole 204, the stator punching 201 mainly moves along the contact surface 1202 of the block 203. The width of the contact surface 1202 is large, which reduces the resistance encountered by the stator punching 201 during the assembly process, thereby reducing the deformation of the stator punching 201, ensuring the installation accuracy, and reducing the influence of the installation process on the tooth slot torque and the back electromotive force waveform distortion rate. In addition, the annular dividing groove 1201 can also be filled with insulating material, and the exposed side of the insulating material and the contact surface 1202 are located in the same curved surface, thereby making the insulating material and the contact surface 1202 excessively smooth, which can reduce the assembly resistance of the stator punching 201, and can also reduce eddy current loss through the isolation effect of the insulating material.

[0063] Reference Fig.13 As shown, it can be understood that, in another embodiment, the stator yoke 202 is composed of a plurality of independent blocks 203, and the plurality of blocks 203 are arranged along the circumference of the mounting hole 204. Along the axial direction of the mounting hole 204, the thickness of each block 203 is equal to the depth of the mounting hole 204, that is, the thickness of each block 203 is greater than the thickness of each stator punching sheet 201. During the process of assembling the stator punching sheet 201 into the mounting hole 204, the stator punching sheet 201 is always in contact with the processing surface of the block 203, and there is no friction force on the stator punching sheet 201 caused by the gap 1101 between the silicon steel sheets, thereby reducing the assembly resistance, and then reducing the deformation of the stator punching sheet 201, so that the installation accuracy is guaranteed, and the influence of the installation process on the cogging torque and the back-EMF waveform distortion rate is reduced.

[0064] It is understandable that the stator yoke 202 can be made of No. 10 steel. The reason why the stator yoke 202 is made of No. 10 steel is that the friction coefficient can be changed, thereby solving the problem of difficult assembly due to friction, and solving the problem of air gap distortion caused by deformation of the stator inner diameter during the press-in process. The stator yoke 202 can also be made of materials such as No. 45 steel and amorphous alloy. In other words, the stator yoke 202 can be made of a machinable material with high magnetic permeability.

[0065] Reference Fig.14As shown, it can be understood that the dark curve represents Figure 1 The back electromotive force variation trend of the stator yoke 101 formed by stamping and laminating multiple cold-rolled silicon steel sheets is shown. The light-colored curve represents Figure 2 The back electromotive force variation trend of the stator yoke 202 made of No. 10 steel composed of a block 203 is shown. According to the finite element calculation, the increase of the stator core loss is limited. Figure 2 The scheme shown is compared to Figure 1 For the scheme shown, the effective value of back EMF is reduced by about 6%.

[0066] Reference Fig.15 As shown, it can be understood that the dark curve represents Figure 1 The back electromotive force variation trend of the stator yoke 101 formed by stamping and laminating multiple cold-rolled silicon steel sheets is shown. The light-colored curve represents Figure 2 The back electromotive force variation trend of the stator yoke 202 made of No. 10 steel composed of a block 203 is shown. According to the finite element calculation, the increase of the stator core loss is limited. Figure 2 The scheme shown is compared to Figure 1 For the scheme shown, the output electromagnetic torque is reduced by about 2%.

[0067] Reference Fig.16 As shown, it can be understood that the utility model also provides a method for manufacturing a stator, which can be applied to Figures 2 to 13 The stator shown includes but is not limited to step S11 to step S12.

[0068] S11: heating the stator yoke;

[0069] S12: Sleeve the stator yoke onto the stator punching sheet.

[0070] By heating the stator yoke, its material can be softened and the assembly stress generated during hard interference assembly can be reduced. This helps to reduce the deformation of the stator yoke caused by assembly stress and improve assembly accuracy. After heating the stator yoke, the material has good plasticity, and it is easier to form good contact and fit during interference assembly, which can effectively transmit torque and bear load. This helps to improve the connection effect between the stator punching and the stator yoke. In the heated state, the thermal expansion coefficient of the stator yoke material will increase, which will reduce the interference, make assembly relatively easy, and reduce the deformation of the stator shoe accordingly. This helps to simplify the assembly process and improve production efficiency. Heating the stator yoke and shrink-fitting the stator punching and stator yoke can solve the problem of inner circle deformation during the stator press-in process and reduce the cost of stamping die opening.

[0071] It is understandable that if Figure 1The stator yoke shown is formed by punching and stacking multiple cold-rolled silicon steel sheets. The manufacturing method using steps S11 to S12 makes it difficult for the thermal expansion deformation of each silicon steel sheet to remain consistent, which may cause the mating surface between the stator yoke and the stator teeth to deteriorate, and the friction force to further increase during assembly, which has the opposite effect.

[0072] Reference Fig.17 As shown, it can be understood that the utility model also provides a method for manufacturing a motor, which can be applied to Figure 2 , Figure 7 and Fig.11 The motor shown includes but is not limited to steps S13 to S14.

[0073] S13: heating the casing;

[0074] S14: Press the stator yoke and stator punching sheets into the housing.

[0075] By heating the casing, its material can be softened and the assembly stress generated during hard interference assembly can be reduced. This helps to reduce the deformation of the casing caused by assembly stress and improve assembly accuracy. After heating the casing, the material has better plasticity, and it is easier to form good contact and fit during interference assembly, which can effectively transfer the heat generated by the stator, which helps to improve the heat dissipation effect of the motor. In the heated state, the thermal expansion coefficient of the casing material will increase, reducing the interference amount and making assembly relatively easy. This helps to simplify the assembly process and improve production efficiency. In addition, shrink-fitting the stator punching and stator yoke can solve the problem of inner circle deformation during stator assembly and reduce the cost of stamping die opening.

[0076] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A motor, characterized in that include: A casing, wherein a receiving cavity is provided inside the casing; Stator punching sheets, a plurality of said stator punching sheets are axially stacked, said stator punching sheets include a plurality of stator shoe portions and stator tooth portions which are circumferentially arranged, and two adjacent stator tooth portions are connected by said stator shoe portions; The stator yoke is arranged in a ring shape, the outer wall of the stator yoke is connected to the accommodating cavity, and the stator teeth are interference-connected to the inner wall of the stator yoke; The material of the stator yoke is different from that of the housing and the stator punching sheet. The inner wall of the stator yoke is formed by machining. The stator yoke is separately molded and then installed in the housing, or the stator yoke is integrally cast with the housing and then molded by machining.

2. The motor according to claim 1, characterized in that The stator yoke is composed of a plurality of blocks, which are arranged along the axial direction of the stator yoke, and an insulating layer is provided between two adjacent blocks. Along the axial direction of the stator yoke, the width of the block is greater than the thickness of the stator punching sheet.

3. The motor according to claim 1, characterized in that The stator yoke is composed of a plurality of segments, and the plurality of segments are arranged along a circumferential direction of the stator yoke.

4. The motor according to claim 1, characterized in that The stator yoke is composed of a block, and the stator yoke is provided with a plurality of annular dividing grooves, and the annular dividing grooves are located on the inner wall of the stator yoke. Each of the annular dividing grooves divides the inner wall surface of the stator yoke into two contact surfaces that are spaced apart. The contact surface is interference-connected with the stator tooth portion, and along the axial direction of the stator yoke, the width of the contact surface is greater than the thickness of the stator punching sheet.

5. The motor according to claim 1, characterized in that The inner wall surface of the stator yoke is provided with a plurality of recesses, the plurality of recesses are distributed at intervals along the circumference of the stator yoke, and the recesses correspond to the positions of the stator teeth one by one.

6. The motor according to claim 5, characterized in that The recessed position is formed by cutting.

7. The motor according to claim 1, characterized in that The inner wall of the accommodating cavity is provided with a limiting portion, and the limiting portion positions the stator yoke along the axial direction of the accommodating cavity.

8. The motor according to claim 1, characterized in that The casing comprises a shell and a base, the shell and the base are detachably connected, and the accommodating cavity is arranged in the shell.

9. The motor according to claim 1, characterized in that The power of the motor is less than or equal to 750W, and the frequency of the motor is 20Hz to 200Hz.

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