Method for manufacturing multi-pole magnetic circuit, multi-pole magnetic circuit, and stepper motor

Abstract

The present application provides a method for manufacturing a multi-pole magnetic circuit, a multi-pole magnetic circuit, and a stepper motor. The manufacturing method comprises the steps of: S1, providing a plurality of first magnetic steels, the cross section of each first magnetic steel being fan-ring-shaped; S2, assembling the obtained plurality of first magnetic steels to obtain a first cylinder; and S3, using a grinding process to grind the side surface of the obtained first cylinder, so as to obtain a second cylinder, and then electroplating the outer surface of the obtained second cylinder to form a coating, so as to obtain a multi-pole magnetic circuit for a stepper motor. According to the method for manufacturing a multi-pole magnetic circuit of the present application, a plurality of first magnetic steels having a large size are first manufactured, the obtained first magnetic steels are then assembled to obtain a first cylinder having a large outer diameter size, and then a grinding process is used to grind the side surface of the obtained first cylinder to obtain a second cylinder having a small outer diameter size, thereby reducing the difficulty of the assembling operation, improving the roundness and concentricity of the multi-pole magnetic circuit, and improving the reliability of the magnetic circuit.

Description

Manufacturing method of multipole magnetic circuit, multipole magnetic circuit and stepper motor Technical Field

[0001] This application relates to the field of motor technology, and in particular to a method for manufacturing a multi-pole magnetic circuit, the multi-pole magnetic circuit, and a stepper motor. Background Technology

[0002] An electric motor is an electromagnetic device that converts or transmits electrical energy. Current stepper motor manufacturing processes include assembling multiple magnets to form a multi-pole magnetic circuit. However, due to the small size of the stepper motor's magnetic circuit, the magnets used for assembly are even smaller, making processing and assembly difficult, and resulting in poor roundness and concentricity of the assembled motor's magnetic circuit.

[0003] Therefore, it is necessary to provide a method for manufacturing a multi-pole magnetic circuit, the multi-pole magnetic circuit, and a stepper motor. Technical issues

[0004] The purpose of this application is to provide a method for manufacturing a multi-pole magnetic circuit, the multi-pole magnetic circuit, and a stepper motor; the multi-pole magnetic circuit is used to manufacture a stepper motor. The multi-pole magnetic circuit has better roundness and concentricity. Technical solutions

[0005] The technical solution of this application is as follows:

[0006] In a first aspect, this application provides a method for manufacturing a multi-pole magnetic circuit for a stepper motor, comprising the following steps: S1, providing a plurality of first magnets, wherein the cross-section of the first magnets is fan-shaped; S2, assembling the plurality of first magnets to obtain a first cylinder; S3, grinding the side surface of the obtained first cylinder using a grinding process to obtain a second cylinder, and then electroplating the outer surface of the obtained second cylinder to form a coating to obtain a multi-pole magnetic circuit for a stepper motor.

[0007] Optionally, the first magnet is shaped by the grinding process to form a second magnet. The second magnet is arranged around the central axis of the multipole magnetic circuit. The ends of two adjacent second magnets that are close to the central axis of the multipole magnetic circuit have opposite magnetism, and the other ends of two adjacent second magnets have opposite magnetism.

[0008] Optionally, in step S3, the grinding process may be one or more of longitudinal grinding, plunge grinding, segmented grinding, or depth grinding.

[0009] Optionally, in step S3, the coating is a Ni metal coating formed by electroplating of metallic Ni, or a composite metal coating formed by Zn and Ni.

[0010] Optionally, the first magnet is a sintered magnet; two adjacent first magnets are bonded and fixed to each other by an adhesive layer.

[0011] Optionally, step S2 may also include providing a rotating shaft; step S2 specifically includes the following steps: providing a rotating shaft, and arranging the obtained multiple first magnets circumferentially around the rotating shaft to obtain a first cylinder with a rotating shaft.

[0012] Secondly, this application provides a multipole magnetic circuit, which is manufactured using the manufacturing method described above.

[0013] Thirdly, this application provides a stepper motor, which includes the multi-pole magnetic circuit described above. Beneficial effects

[0014] The beneficial effects of this application are as follows: The manufacturing method of the multi-pole magnetic circuit of this application involves first preparing multiple first magnets with larger dimensions, then splicing and assembling the obtained first magnets to obtain a first cylinder with a larger outer diameter, and then using a grinding process to grind the side of the obtained first cylinder to obtain a second cylinder with a smaller outer diameter. This reduces the difficulty of splicing operations, improves the roundness and concentricity of the multi-pole magnetic circuit, and ensures precise control of the outer diameter tolerance of the magnetic circuit and the reliability of the magnetic circuit. Attached Figure Description

[0015] Figure 1 is a process flow diagram of the manufacturing method of the multipole magnetic circuit of this application.

[0016] Figure 2 is a schematic diagram of the structure of the multi-stage magnetic circuit obtained in this application.

[0017] Figure 3 is a schematic diagram of the magnetic distribution of the second magnet in a multipole magnetic circuit.

[0018] Figure 4 is a schematic diagram of the stepper motor of this application.

[0019] Figure 5 is a top view of the stepper motor of this application.

[0020] Figure 6 is a cross-sectional view of Figure 5 along AA.

[0021] Figure 7 is a schematic diagram of the claw pole assembly.

[0022] Figure 8 is a schematic diagram of the claw pole structure.

[0023] Figure 9 is another process flow diagram of the manufacturing method of the multi-pole magnetic circuit of this application. Embodiments of the present invention

[0024] The present application will be further described below with reference to the accompanying drawings and embodiments. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and should not be construed as limiting the present application.

[0025] To enable those skilled in the art to better understand the solutions of this application, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them.

[0026] In the description of this application, the terms "first," "second," "third," "fourth," etc., are used only for the purpose of distinguishing descriptions and should not be construed as indicating or implying relative importance or order.

[0027] It should be noted that, in this application, "outer direction" refers to the direction away from the central axis of the multipole magnetic circuit, and "inner direction" refers to the direction close to the central axis of the multipole magnetic circuit.

[0028] Example 1: In a first aspect, this application provides a method for manufacturing a multipole magnetic circuit 110, which is used to prepare a stepper motor. Referring to Figures 1 and 2, the method includes the following steps: S1, providing a plurality of first magnets 1, wherein the cross-section of the first magnets 1 is fan-shaped; S2, assembling the plurality of first magnets 1 to obtain a first cylinder 2; S3, grinding the side surface of the obtained first cylinder 2 using a grinding process to obtain a second cylinder 3, and then electroplating the outer surface of the obtained second cylinder 3 to form a coating 113, thereby obtaining a multipole magnetic circuit 110 for a stepper motor.

[0029] The manufacturing method of the multi-pole magnetic circuit 110 described in this application is applicable to the manufacturing of stepper motors. First, multiple first magnets 1 with larger dimensions are prepared. Then, the obtained first magnets 1 are spliced ​​and assembled to obtain a first cylinder 2 with a larger outer diameter. The side surface of the obtained first cylinder 2 is ground by a grinding process to obtain a second cylinder 3 with a smaller outer diameter. The first magnet 1, with its larger size, is not only easy to process but also has a lower assembly difficulty, ensuring the roundness and concentricity of the assembled first cylinder 2, thus providing a foundation for manufacturing a multi-pole magnetic circuit 110 with better roundness and concentricity. Then, the outer diameter of the large first cylinder 2 is ground into a second cylinder 3 with a smaller outer diameter as required by a grinding process, thereby precisely controlling the outer diameter tolerance of the magnetic circuit. The ground second cylinder 3 is then electroplated to ensure the reliability of the magnetic circuit. In addition, in step S2, according to actual needs, the deformation of the outer diameter during the grinding process can be controlled to prepare second cylinders 3 with different outer diameters to meet the assembly requirements of stepper motors of different sizes.

[0030] Preferably, the second cylinder 3 includes second magnets 111 spliced ​​together, the second magnets being formed by the first magnets 1 after being processed by the grinding process; the magnetic properties of two adjacent second magnets 111 are opposite at one end near the central axis of the second cylinder 3, and the magnetic properties of the other ends of two adjacent second magnets 111 are opposite.

[0031] The plurality of first magnets 1 may include 2 first magnets 1, 3 first magnets 1, 4 first magnets 1, 5 first magnets 1, 6 first magnets 1, 8 first magnets 1, etc. Correspondingly, the second magnets 111 formed after the grinding process may include 2 second magnets 111, 3 second magnets 111, 4 second magnets 111, 5 second magnets 111, 6 second magnets 111, 8 second magnets 111, etc.

[0032] For example, in one embodiment, when the number of second magnets 111 is eight, the eight second magnets 111 are spliced ​​together to form the second cylinder 3. The magnetic properties of the end of each second magnet 111 furthest from the central axis of the second cylinder 3 and the end closest to the central axis of the second cylinder 3 are opposite. For example, referring to Figure 3, if the magnetic pole of the end of one second magnet 111 closest to the central axis of the second cylinder 3 is the N pole, then the magnetic pole of the other end of that second magnet 111 furthest from the central axis of the second cylinder 3 is the S pole. Furthermore, in two adjacent second magnets 111, the magnetic properties of the ends of the two second magnets 111 closest to the central axis of the second cylinder 3 are opposite. For example, if the magnetic pole of one second magnet 111 furthest from the central axis of the second cylinder 3 is the N pole, then the magnetic pole of the other adjacent second magnet 111 furthest from the central axis of the second cylinder 3 is the S pole. The magnetic properties of the other ends of two adjacent second magnets 111 are opposite. For example, if the magnetic pole of the end of one second magnet 111 that is away from the central axis of the second cylinder 3 is the S pole, then the magnetic pole of the end of the other second magnet 111 that is adjacent to the second magnet 111 that is away from the central axis of the second cylinder 3 is the N pole.

[0033] In step S3, the first cylinder 2 is processed through a grinding process to obtain the second cylinder 3. The specific outer diameter of the first cylinder 2 and the outer diameter of the formed second cylinder 3 can be specifically set according to actual needs.

[0034] For example, in one specific embodiment of this application, the deformation of the outer diameter of the first cylinder 2 can be 42.8125%-43.4375%; the outer diameter of the first cylinder 2 can be 3.2mm, and the outer diameter of the second cylinder 3 can be 1.82±0.01mm.

[0035] Optionally, in step S3, the grinding process includes one or more of longitudinal grinding, plunge grinding, segmented grinding, or depth grinding.

[0036] Optionally, in step S3, the coating 113 is a Ni metal coating formed by Ni electroplating, or a composite metal coating formed by Zn and Ni. Performing electroplating after the grinding process ensures that a uniform coating is formed on the outer side of the second cylinder 3, guaranteeing the stability of the magnet.

[0037] Optionally, the first magnet 1 is a sintered magnet; the use of sintered magnets can effectively improve the torque of the product and enhance the magnetic circuit performance; in addition, multiple first magnets 1 can be pre-processed and formed separately before being spliced ​​together, which can simplify the assembly process, meet the assembly requirements of motors of different sizes, improve stability and reliability, and help improve the driving performance of the motor.

[0038] Two adjacent first magnets 1 are bonded and fixed to each other by an adhesive layer 112; the adhesive layer 112 can be glue, and fixing two adjacent first magnets 1 by the adhesive layer 112 can improve the stability of multiple first magnets 1 after splicing.

[0039] Secondly, this application provides a multipole magnetic circuit 110, which is manufactured using the manufacturing method described above.

[0040] Thirdly, this application provides a stepper motor, as shown in Figures 4 to 6, the stepper motor including a rotor assembly 100 and a stator assembly 200 sleeved on the outer periphery of the rotor assembly 100; the rotor assembly 100 includes a multipole magnetic circuit 110 made by the manufacturing method described above or a multipole magnetic circuit 110 as described above.

[0041] The multi-pole magnetic circuit 110 is generally in the shape of a hollow cylinder, and includes a plurality of second magnets 111 spliced ​​together; the rotor assembly 100 also includes a rotating shaft 120 that passes through the center axis of the multi-pole magnetic circuit 110; that is, the plurality of second magnets 111 are arranged circumferentially along the rotating shaft 120; the magnetism of two adjacent second magnets 111 near the rotating shaft 120 is opposite, and the magnetism of the other ends of two adjacent second magnets 111 is opposite.

[0042] Two adjacent second magnets 111 are bonded and fixed to each other by an adhesive layer 112; the outer surface of the multipole magnetic circuit 110 is provided with a coating 113.

[0043] In some embodiments, the stepper motor includes a rotor assembly 100 and a stator assembly 200; in other embodiments, the stepper motor includes a rotor assembly 100 and a plurality of stator assemblies 200 arranged sequentially along the axial direction of the rotor assembly 100.

[0044] The stator assembly 200 includes, from the inside out, a claw pole assembly 210, a plastic part 220, a coil 230, and a housing 240, which are sequentially fitted around the rotor assembly 100. The claw pole assembly 210 includes two claw poles 211 arranged opposite each other and spaced apart. Referring to Figure 8, each claw pole 211 includes a claw disk 2111, a plurality of claw fingers 2112 distributed circumferentially and vertically along the claw disk 2111, and a limiting portion 2113 extending outward from the claw disk 2111. The claw fingers 2112 are toothed, with the wider end of each claw finger connected to the claw disk 2111. The housing 240 has a limiting groove for the limiting portion 2113 to be inserted. The number of claw fingers 2112 is three or four, and the claw fingers 2112 are evenly distributed circumferentially along the claw disk 2111.

[0045] The rotor assembly 100 further includes a flexible circuit board 300 electrically connected to the coil 230, the flexible circuit board 300 being disposed outside the housing 240. The stepper motor also includes end caps 400, the end caps 400 being disposed at both ends of the housing 240, the two ends of the rotating shaft 120 respectively passing through the end caps 400, and the two ends of the rotating shaft 120 respectively being connected to the end caps 400 via bearings 130.

[0046] The number of stator components 200 can be any integer from 1 to 4.

[0047] As one embodiment, referring to Figures 6 and 7, when the stepper motor includes one rotor assembly 100 and four stator assemblies 200 arranged sequentially along the axial direction of the rotor assembly 100; the stator assembly 200 includes a first stator assembly 212, a second stator assembly 213, a third stator assembly 214, and a fourth stator assembly 215 arranged sequentially from one end of the rotor assembly 100 to the other end; the end cover 400 includes a first end cover 410 connected to one end of the rotating shaft 120 and a second end cover 420 connected to the other end of the rotating shaft 120.

[0048] The first stator assembly 212 includes a first claw pole assembly 2121, a first plastic part 2122, a first coil 2123, and a first outer shell 2124 arranged sequentially from the inside out. The first claw pole assembly 2121 includes a first claw pole 21211 and a second claw pole 21212 arranged opposite to each other and spaced apart; the first claw pole 21211 includes a first claw disc 212111, a first claw finger 212112, and a first limiting part 212113, and the second claw pole 21212 includes a second claw disc 212121, a second claw finger 212122, and a second limiting part 212123. The first claw finger 212112 is inserted into the gap of the second claw finger 212122. The outer walls of the first claw disk 212111 and the second claw disk 212121 are connected to the inner wall of the first outer shell 2124. The first claw disk 212111 is connected to the first end cap 410. The first limiting part 212113 and the second limiting part 212123 are offset along a direction parallel to the central axis of the rotating shaft 120. The first claw disk 212111, the first claw finger 212112, the second claw finger 212122, the second claw disk 212121 and the first outer shell 2124 together form a first mounting groove. The first plastic part 2122 and the first coil 2123 are disposed in the first mounting groove from the inside to the outside.

[0049] The second stator assembly 213 includes a second claw pole assembly 2131, a second plastic part 2132, a second coil 2133, and a second outer casing 2134 arranged sequentially from the inside out. The second claw pole assembly 2131 includes a third claw pole 21311 and a fourth claw pole 21312 arranged opposite to and spaced apart from each other. The third claw pole 21311 includes a third claw disc 213111, a third claw finger 213112, and a third limiting part 213113. The fourth claw pole 21312 includes a fourth claw disc 213121, a fourth claw finger 213122, and a fourth limiting part 213123. The third claw finger 213112 is inserted into the gap of the fourth claw finger 213122. The outer walls of the third claw disc 213111 and the fourth claw disc 213121 are connected to the second outer casing. The inner wall of 2134, the third claw disk 213111 is connected to the first claw disk 212111, the third limiting part 213113 is connected to the first limiting part 212113, and the fourth limiting part 213123 is offset from the first limiting part 212113 and the second limiting part; the third claw disk 213111, the third claw finger 213112, the fourth claw finger 213122, the fourth claw disk 213121 and the outer shell 240 together form a second mounting groove, and the second plastic part 2132 and the second coil 2133 are disposed in the second mounting groove from the inside to the outside.

[0050] The third stator assembly 214 includes a third claw pole assembly 2141, a third plastic part 2142, a third coil 2143, and a third outer shell 2144, arranged sequentially from the inside out. The third claw pole assembly 2141 includes a fifth claw pole 21411 and a sixth claw pole 21412 arranged opposite to and spaced apart from each other. The fifth claw pole 21411 includes a fifth claw disc 214111, a fifth claw finger 214112, and a fifth limiting part 214113. The sixth claw pole 21412 includes a sixth claw disc 214121, a sixth claw finger 214122, and a sixth limiting part 214123. The fifth claw finger 214112 is inserted into the gap of the sixth claw finger 214122. The outer walls of the fifth claw disc 214111 and the sixth claw disc 214121 are connected to the third... The inner wall of the outer shell 2144, the fifth claw disk 214111 is connected to the fourth claw disk 213121, the fifth limiting part 214113 is aligned with the first limiting part 212113, and the sixth limiting part 214123 is aligned with the second limiting part 212123; the fifth claw disk 214111, the fifth claw finger 214112, the sixth claw finger 214122, the sixth claw disk 214121 and the outer shell 240 together form a third mounting groove, and the third plastic part 2142 and the third coil 2143 are disposed in the third mounting groove from the inside to the outside.

[0051] The fourth stator assembly 215 includes a fourth claw pole assembly 2151, a fourth plastic part 2152, a fourth coil 2153, and a fourth outer casing 2154 arranged sequentially from the inside out. The fourth claw pole assembly 2151 includes a seventh claw pole 21511 and an eighth claw pole 21512 arranged opposite to each other and spaced apart. The seventh claw pole 21511 includes a seventh claw disc 215111, a seventh claw finger 215112, and a seventh limiting part 215113. The eighth claw pole 21512 includes an eighth claw disc 215121, an eighth claw finger 215122, and an eighth limiting part 215123. The seventh claw finger 215112 is inserted into the gap of the eighth claw finger 215122. The outer walls of the seventh claw disc 215111 and the eighth claw disc 215121 are connected to the inner wall of the fourth outer casing 2154. The seventh claw disk 215111 is connected to the sixth claw disk 214121, the eighth claw disk 215121 is connected to the second end cover 420, the seventh limiting part 215113 is aligned with the sixth limiting part 214123, and the eighth limiting part 215123 is aligned with the fourth limiting part 213123; the seventh claw disk 215111, the seventh claw finger 215112, the eighth claw finger 215122, the eighth claw disk 215121 and the outer shell 240 together form a fourth mounting groove, and the fourth plastic part 2152 and the fourth coil 2153 are disposed in the fourth mounting groove from the inside to the outside.

[0052] Alternatively, in some other embodiments, as shown in Figure 9, step S2 further includes providing a rotating shaft 120; step S2 specifically includes the following steps: providing a rotating shaft 120, arranging the obtained plurality of first magnets 1 circumferentially around the rotating shaft 120 to obtain a first cylinder 2 with the rotating shaft 120; and obtaining a second cylinder 3 with the rotating shaft 120 after the grinding process.

[0053] Comparative Example 1: Compared with Example 1, the outer diameter of the multipole magnetic circuit 110 in Comparative Example 1 is the same as that in Example 1, and the number of spliced ​​magnets is the same. The difference is that the multipole magnetic circuit 110 in Comparative Example 1 directly prepares a third magnet with the same outer diameter as the second magnet 111, and then splices the third magnet to obtain a third cylinder with the same outer diameter as the second cylinder 3. Then, the surface of the third cylinder is electroplated to obtain the multipole magnetic circuit 110.

[0054] Compared with Comparative Example 1, the concentricity of the multipole magnetic circuit 110 manufactured by the manufacturing method described in this application is improved from ±5s to ±1s. The roundness and concentricity of the multipole magnetic circuit 110 manufactured by the manufacturing method described in this application are better, and the reliability of the magnetic circuit is better.

[0055] The above description is merely an embodiment of this application. It should be noted that those skilled in the art can make improvements without departing from the inventive concept of this application, but these improvements all fall within the protection scope of this application.

Claims

1. A method of manufacturing a multipole magnetic circuit, characterized by, The method comprises the following steps: S1, providing a plurality of first magnetic steels, the cross section of the first magnetic steels being in the shape of a fan ring; S2, assembling the plurality of first magnetic steels to obtain a first cylinder; S3, grinding the side surface of the first cylinder by using a grinding process to obtain a second cylinder, and then electroplating the outer surface of the second cylinder to form a coating layer, thereby obtaining a multipole magnetic circuit for a stepping motor.

2. The manufacturing method according to claim 1, characterized in that: The first magnetic steels are shaped into second magnetic steels by the grinding process, the second magnetic steels are arranged around the central axis of the multipole magnetic circuit, the magnetic properties of two adjacent second magnetic steels are opposite to each other at one end close to the central axis of the multipole magnetic circuit, and the magnetic properties of the other ends of the two adjacent second magnetic steels are opposite to each other.

3. The production method according to claim 1, characterized by, In step S3, the grinding process comprises one or more of longitudinal grinding, plunge grinding, segmented grinding, and depth grinding.

4. The production method according to claim 1, characterized by In step S3, the coating layer is a Ni metal coating layer formed by electroplating metal Ni, or a composite metal coating layer formed by Zn and Ni.

5. The production method according to claim 1, wherein The first magnetic steels are sintered magnetic steels, and two adjacent first magnetic steels are fixed to each other by an adhesive layer.

6. The production method according to any one of claims 1 to 5, characterized by, In step S2, a rotating shaft is further provided, and step S2 specifically comprises the following steps: providing a rotating shaft, and arranging the plurality of first magnetic steels around the rotating shaft in a circumferential direction to obtain a first cylinder provided with the rotating shaft.

7. A multipole magnetic circuit, characterized by The multipole magnetic circuit is manufactured by using the manufacturing method of any one of claims 1-6.

8. A stepper motor characterized by The stepping motor comprises the multipole magnetic circuit of claim 7.

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