A method of machining an electric motor rotor and an electric motor rotor produced using the same

Abstract

The application discloses a motor rotor processing method and a motor rotor produced by using the same, and belongs to the motor processing field. The processing method comprises the following steps: S1, distributing a plurality of commutating sheets in a shaping mold in a circumferential direction; S2, pouring a shaping material into the shaping mold to make the commutating sheets and the shaping material solidify to form a ring-shaped commutator in the mold; S3, sleeving the commutator on one end of an iron core provided with windings, and then bonding and fixing the commutator and the iron core provided with windings; and S4, welding and fixing the enameled wire of the windings and the commutating sheets to form a motor rotor. By using the mold and the shaping material to fix the plurality of commutating sheets in the mold to form the commutating ring with high uniformity of the circumferential distribution of the fixed commutating sheets, and then fixing the commutating ring and the iron core, the circumferential uniform distribution of the commutating sheets in the whole process can be ensured without the shaping of the tool.

Description

Technical Field

[0001] This invention belongs to the field of motor processing, specifically a method for processing motor rotors and a motor rotor produced using the same method. Background Technology

[0002] The existing method for machining motor rotors involves using tooling to fix the commutator segments to predetermined positions on the iron core. Then, the tooling is removed, and a fixing agent is used to fix the commutator segments to the iron core to form a commutator at the end of the iron core. In this scheme, the commutator adopts a single-piece structure design, and there is no mechanical positioning between the segments, resulting in poor uniformity of the commutator segments' circumferential distribution. Tooling is needed to shape the segments to ensure uniform circumferential distribution. However, when fixing the commutator segments to the iron core, the tooling needs to be removed. At this time, the commutator segments will be moved or deflected under force, resulting in poor circumferential distribution. Summary of the Invention

[0003] Objective of the invention: To provide a method for processing a motor rotor that can improve the uniformity of the circumferential distribution of commutator segments fixed on an iron core, and a motor rotor produced using the method, so as to solve the above-mentioned problems existing in the prior art.

[0004] Technical solution: In a first aspect, a method for processing an electric motor rotor includes: S1. distributing a plurality of commutator segments circumferentially within a forming mold.

[0005] S2. Pour shaping material into the shaping mold, so that the commutator segments and shaping material solidify in the mold to form an annular commutator.

[0006] S3. Place the commutator on one end of the iron core with windings, and then bond and fix the commutator to the iron core with windings.

[0007] S4. Weld the enameled wire of the winding to the commutator segments to form the motor rotor.

[0008] In a further embodiment of the first aspect, the motor rotor processing method further includes: S3-1. Before the commutator is fitted onto one end of the iron core with windings, an insulating material is coated on the end face and inner wall of the commutator near the iron core to form an insulating layer.

[0009] and / or

[0010] S3-2. Before the commutator is fitted onto one end of the iron core with windings, an insulating layer is formed by coating the end face and outer wall of the iron core near the commutator with insulating material.

[0011] S3-3. Based on S3-1 and / or S3-2, the commutator is fitted onto one end of the iron core with windings, and the shaping material and insulating material are heated to bond and fix the commutator to the iron core. By first forming a fixed commutator, a fixed and uniform insulating layer can be formed between the commutator and the iron core before the commutator is connected to the iron core, ensuring the assembly quality and insulation performance of the commutator and the iron core.

[0012] In a further embodiment of the first aspect, the motor rotor processing method further includes: S3-4. In S3, the outer side of the commutator is surface-shaped so that the shape and size of the outer side of the commutator matches the shape and size of the outer side of the iron core.

[0013] S3-5. The commutator is subjected to surface coating strengthening treatment. By modifying the shape and surface coating strengthening treatment, the surface hardness of the commutator can be improved, making it more wear-resistant and ensuring the resistance stability of the armature.

[0014] In a further embodiment of the first aspect, the motor rotor processing method further includes: before S3, forming a frustum-shaped adhesive portion at one end of the iron core with windings using an adhesive material.

[0015] An annular ramp that mates with the adhesive part is provided at one end of the inner side of the commutator.

[0016] In S3, when the commutator is fitted onto one end of the iron core with windings, the annular ramp inside the commutator abuts against the adhesive part. The frustum-shaped adhesive part guides the annular ramp of the commutator, reducing the difficulty of maintaining the coaxiality of the iron core and the commutator and improving the yield rate.

[0017] In another embodiment of the first aspect, the motor rotor processing method further includes: assembling a mold.

[0018] The assembly mold includes: a base.

[0019] The positioning cylinder is connected to the base.

[0020] The central column is connected to the base and housed in the positioning cylinder, and its coaxiality with the positioning cylinder is within a predetermined range.

[0021] The positioning cylinder has a frustum cavity that communicates with the outside. The inner diameter of the frustum cavity at the end closer to the base is smaller than the inner diameter at the end farther from the base.

[0022] In S2, one end of the commutator is shaped like a frustum ring.

[0023] In S3, the winding iron core is first fitted onto the center post, and then the frustum-shaped end of the commutator is fitted onto the winding iron core, so that the outer wall of the frustum-shaped commutator abuts against the inner wall of the frustum cavity of the positioning cylinder. Then, the commutator and the winding iron core are bonded and fixed. After the commutator and the iron core are removed from the assembly mold, the outer surface of the commutator is surface-shaped to match the outer shape and size of the commutator with the outer shape and size of the iron core. By using the assembly mold to position the commutator and the iron core during assembly, the frustum cavity can guide the commutator, reducing the difficulty of maintaining the coaxiality of the iron core and the commutator and improving the yield rate.

[0024] In a second aspect, the motor rotor produced using the motor rotor processing method described in the first aspect includes: an iron core having a through cavity inside and a plurality of pole slots outside.

[0025] The winding consists of several enameled wires wound around the pole slot.

[0026] The commutator also includes a fixing part that is sleeved on the iron core at one end, and a number of commutator segments inserted into the other end of the fixing part.

[0027] The end of the commutator segment away from the fixing part is connected to the enameled wire. The commutator segment is fixed as a whole by the fixing part of the commutator, which can improve the stability of the relative position of the commutator segment.

[0028] In a further embodiment of the second aspect, the number of pole slots in the iron core is Z, and the number of commutator segments is K.

[0029] K = μZ, μ ≥ 1, μ is a natural number. By fixing the commutator segments, a virtual slot structure with the number of commutator segments being μ times the number of pole slots can be achieved while ensuring that the position of the commutator segments is fixed. After increasing the number of virtual slots, the number of winding elements increases by μ times. Under the same number of slots, the number of series elements will increase by μ times. The corresponding current fluctuation is about 1 / μ times the number of real slots, which is greatly reduced and can meet the requirement that the change rate is not greater than 0.2A.

[0030] In a further embodiment of the second aspect, the inner wall of the commutator is provided with a plurality of positioning portions that are engaged with the pole slots, the positioning portions being rectangular protrusions whose side walls abut against the inner walls of the pole slots.

[0031] The positioning part is provided with a trapezoidal protrusion or a triangular protrusion at the end away from the commutator segment. The width of the part near the commutator segment is greater than the width of the part away from the commutator segment. The positioning part, which matches the position of the commutator segment, can ensure that the position of the commutator segment matches the position of the pole slot during assembly, which facilitates the connection between the commutator segment and the enameled wire.

[0032] In a further embodiment of the second aspect, a welding groove is provided at the end of the commutator away from the fixing part, and the end of the enameled wire is received in the welding groove.

[0033] The fixing part is higher than the bottom wall of the welding groove on the side near the iron core, which can prevent the solder from flowing into the winding when the enameled wire is welded to the commutator segment.

[0034] The end of the commutator segment away from the iron core and the fixing part has a stepped surface higher than the bottom wall of the welding tank. The purpose of the stepped surface design is to observe whether the solder in the welding tank is full and free of voids and incomplete soldering.

[0035] In a further embodiment of the second aspect, the commutator segment housed in the fixing part is provided with a groove on its side. By providing the groove, the commutator segment can be prevented from rotating or even falling off in the fixing part, making its connection structure with the fixing part more stable.

[0036] Beneficial effects: This invention discloses a method for processing an electric motor rotor and an electric motor rotor produced using the method. By first using a mold and shaping material to fix several commutator segments in the mold to form a fixed commutator ring with high uniformity of circumferential distribution of commutator segments, and then fixing the commutator ring to the iron core, it is possible to ensure uniform circumferential distribution of commutator segments throughout the process without tooling shaping. This solves the problem in the prior art where, when commutator segments are fixed to the iron core, the commutator segments move or deflect under force after the tooling is removed, resulting in poor uniformity of circumferential distribution. Attached Figure Description

[0037] Figure 1 This is an exploded isometric view of the motor rotor before the commutator of this application undergoes surface shaping treatment.

[0038] Figure 2 This is a schematic diagram of the motor rotor assembly before the commutator of this application undergoes surface shaping treatment.

[0039] Figure 3 This is a schematic side section of the motor rotor before the commutator of this application undergoes surface shaping treatment.

[0040] Figure 4 This is a partial cross-sectional view of the positioning part of this application.

[0041] Figure 5 This is an enlarged schematic diagram of the commutator segment of this application.

[0042] Figure 6 This is a schematic diagram of an embodiment of the bonding portion formed at one end of the iron core in this application, which is a frustum-shaped ring.

[0043] Figure 7 This is a schematic diagram of an embodiment of the assembly using an assembly mold in this application.

[0044] Figures 1 to 7 The attached figures are labeled as follows: 1. Iron core; 2. Winding; 3. Commutator; 4. Assembly mold; 11. Adhesive part; 31. Fixing part; 32. Commutator segment; 33. Positioning part; 41. Base; 42. Positioning cylinder; 43. Center column. Detailed Implementation

[0045] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid obscuring the invention.

[0046] This invention discloses a method for processing motor rotors that can improve the uniformity of the circumferential distribution of commutator segments fixed on an iron core, and a motor rotor produced using the method.

[0047] The motor rotor processing method includes: S1. Distributing a number of commutator segments 32 circumferentially in a forming mold. The commutator segments 32 of this application can be made of copper or rare and precious metal silver-copper-nickel alloy plate AgCuNi20-2. When cost and other conditions permit, rare and precious metal silver-copper-nickel alloy plate AgCuNi20-2 with good conductivity is preferred as the commutator segment 32.

[0048] S2. Pour shaping material into the shaping mold, so that the commutator segment 32 and the shaping material solidify in the mold to form an annular commutator 3. The shaping material can be 4330 phenolic glass fiber compression molding material, or epoxy resin material, or the outer side connected to the commutator segment 32 can be 4330 phenolic glass fiber compression molding material, and the inner side connected to the iron core 1 can be epoxy resin material.

[0049] S3. For example Figure 1 , 6 As shown in Figure 7, the commutator 3 is fitted onto one end of the iron core 1 with the winding 2, and then the commutator 3 is bonded and fixed to the iron core 1 with the winding 2.

[0050] S4. In this embodiment, the end of the enameled wire that makes up the winding 2 extends a predetermined distance toward the commutator 3. After the commutator 3 and the core 1 are fixed at predetermined positions, the end of the enameled wire is bent toward the position of the corresponding commutator segment 32. Then, the enameled wire of the winding 2 and the commutator segment 32 are welded and fixed to form the motor rotor.

[0051] Working principle: By first using a mold and shaping material to fix several commutator segments 32 in the mold to form a fixed commutator segment 32 with high circumferential uniformity, the commutator segment 32 is then fixed to the iron core 1. This ensures that the commutator segment 32 is evenly distributed around the circumference throughout the process without tooling shaping. This solves the problem in the prior art where the commutator segment 32 moves or deflects under force after the tooling is removed when it is fixed on the iron core 1, resulting in poor circumferential uniformity.

[0052] In a further embodiment of the first aspect, the end face and inner wall of the existing commutator segment 32 have no insulating layer, and insulation is only achieved by the thickness of the insulating end plate and the insulating paper. When the motor operates for a long time, this structure has the problem of reduced insulation performance, which leads to motor damage.

[0053] To solve the above problems, the motor rotor processing method further includes: S3-1. Before the commutator 3 is fitted onto one end of the iron core 1 with winding 2, an insulating material is coated on the end face and inner wall of the commutator 3 near the iron core 1 to form an insulating layer.

[0054] In this embodiment, the insulation layer can be formed by pouring the shaping material into the shaping mold after S2 to form the commutator 3, and then pouring or coating the insulation material to form the insulation layer. When the shaping material is epoxy resin, there is no need for secondary pouring or coating, and the commutator 3 of the predetermined shape can be formed in one pour and used directly.

[0055] and / or

[0056] S3-2. Before the commutator 3 is fitted onto one end of the iron core 1 with the winding 2, an insulating layer is formed by coating the end face and outer wall of the iron core 1 near the commutator 3 with insulating material.

[0057] S3-3. Based on S3-1 and / or S3-2, the commutator 3 is fitted onto one end of the iron core 1 with the winding 2, and the shaping material and insulating material are heated to bond and fix the commutator 3 to the iron core 1.

[0058] In this embodiment, the insulating layer can be made of epoxy resin material, and the thickness of the insulating layer is between 0.2-0.5 mm, with a thickness of 0.3 mm being the most preferred.

[0059] By first forming a fixed commutator 3, a fixed and uniform insulating layer can be formed between the commutator 3 and the iron core 1 before the commutator 3 is connected to the iron core 1. This ensures the assembly quality and insulation performance of the commutator 3 and the iron core 1, and solves the problem that the insulation performance of the existing technology is reduced during long-term operation, which leads to motor damage.

[0060] In a further embodiment of the first aspect, S3-4. In S3, the outer side of the commutator 3 is surface-shaped so that the shape and size of the outer side of the commutator 3 matches the shape and size of the outer side of the core 1.

[0061] S3-5. Perform surface coating reinforcement treatment on commutator 3.

[0062] In this embodiment, the outer surface of the commutator 3 can be modified by precision turning or precision milling.

[0063] In this embodiment, the coating enhancement treatment on the surface of the commutator 3 is preferably a surface palladium plating treatment.

[0064] By modifying the shape and strengthening the surface with a coating, the hardness of the commutator 3 surface can be improved, making it more wear-resistant. In particular, when the surface is coated with palladium, the hardness and wear resistance of the commutator 3 are improved while the resistance stability of the armature is also guaranteed.

[0065] In a further embodiment of the first aspect, in the prior art, the components of the motor are generally designed as cylindrical structures. When the commutator 3 is fitted onto one end of the iron core 1 with the winding 2, there is a problem that it is difficult to maintain the coaxiality between the iron core 1 and the commutator 3.

[0066] To solve the above problems, the motor rotor processing method further includes: before S3, using an adhesive material to form a frustum-shaped adhesive portion 11 at one end of the iron core 1 with winding 2.

[0067] An annular ramp that mates with the adhesive part 11 is provided at one end of the inner side of the commutator 3.

[0068] In S3, when the commutator 3 is fitted onto one end of the iron core 1 with the winding 2, the annular ramp inside the commutator 3 abuts against the adhesive part 11.

[0069] The adhesive part 11 can be an epoxy resin that has both adhesive and insulating properties.

[0070] The frustum-shaped adhesive part 11 can guide the annular ramp of the commutator 3, reducing the difficulty of maintaining the coaxiality of the core 1 and the commutator 3 and improving the yield rate.

[0071] In another embodiment of the first aspect, the motor rotor processing method further includes: assembly mold 4.

[0072] The assembly mold 4 includes: a base 41.

[0073] Positioning cylinder 42 is connected to base 41.

[0074] The central column 43 is connected to the base 41 and housed in the positioning cylinder 42, and its coaxiality with the positioning cylinder 42 is within a predetermined range.

[0075] The positioning cylinder 42 has a frustum cavity that communicates with the outside. The inner diameter of the frustum cavity at the end near the base 41 is smaller than the inner diameter at the end away from the base 41.

[0076] In S2, one end of the commutator 3 produced is shaped like a frustum ring.

[0077] In S3, the iron core 1 with winding 2 is first fitted onto the central column 43. Then, the frustum-shaped end of the commutator 3 is fitted onto the iron core 1 with winding 2, so that the outer wall of the frustum-shaped commutator 3 abuts against the inner wall of the frustum cavity of the positioning cylinder 42. Then, the commutator 3 is bonded and fixed to the iron core 1 with winding 2. After the commutator 3 and the iron core 1 are taken out from the assembly mold 4, the outer side of the commutator 3 is surface-shaped so that the outer shape and size of the commutator 3 match the outer shape and size of the iron core 1.

[0078] By using the assembly mold 4 to position the commutator 3 and the iron core 1 during assembly, the frustum cavity can guide the commutator 3, reducing the difficulty of maintaining the coaxiality of the iron core 1 and the commutator 3 and improving the yield rate. Then, the outer surface of the commutator 3 is shaped to make the commutator 3 meet the usage requirements.

[0079] In a second aspect, the motor rotor produced using the motor rotor processing method described in the first aspect includes: an iron core 1, a winding 2, and a commutator 3.

[0080] The iron core 1 has a through cavity inside and several pole slots outside it. The pole slots are through slots that connect to the outside at predetermined parts on the side.

[0081] Winding 2 consists of several enameled wires wound around the pole slot.

[0082] The commutator 3 also includes a fixing part 31 with one end sleeved on the iron core 1, and a plurality of commutator segments 32 inserted at the other end of the fixing part 31.

[0083] The end of the commutator 32 away from the fixing part 31 is connected to the enameled wire.

[0084] In this embodiment, the fixing part 31 is made of 4330 phenolic glass fiber compression molding material, or it can be made of epoxy resin material. Alternatively, the outer side connecting with the commutator segment 32 can be made of 4330 phenolic glass fiber compression molding material, and the inner side connecting with the iron core 1 can be made of epoxy resin material.

[0085] By fixing the commutator segment 32 into a single unit using the fixing part 31 of the commutator 3, the stability of the relative position of the commutator segment 32 can be improved. This solves the problem in the prior art where the commutator segment 32 moves or deflects under force after the tooling is removed when it is fixed on the iron core 1, resulting in poor circumferential distribution.

[0086] In a further embodiment of the second aspect, in the prior art, the commutator 32 must be inserted into the pole slot of the iron core 1 to achieve the installation and fixation of the commutator 32. This technical solution is a solid slot structure in which the commutator 32 and the pole slot of the iron core 1 are matched one by one. The traditional structure without virtual slots, that is, the number of slots of the commutator 3 and the number of slots of the lamination are the same, is adopted. Under the outer diameter of the stator 53, it is more appropriate to select the number of pole pairs 4 and the number of poles 5.

[0087] For torque motors, a single-wave winding 2 is often used, and the number of slots Z and the number of commutator segments K are determined by the following formula:

[0088] Z = K = m * 2 * P ± 1

[0089] In the formula, m is the number of slots per pole pair, and m is generally taken as 8, 15, or 2P, which is the number of pole pairs of the motor.

[0090] With 2P=8, the number of slots can be limited. For m=8, 9, 10, and 11, the possible number of slots are 31, 33, 35, 37, 39, 41, 43, and 45 respectively. However, increasing the number of slots further results in a very small slot shape, further reducing the effective area for conductor filling, making it unsuitable to increase the number of slots further.

[0091] Similarly, with 2P=10, the number of slots available will be more limited, ranging from 39, 41, 43, to 45.

[0092] According to the principle of the motor, the single-wave winding 2 is connected in parallel with two branches, which means that the number of components in each branch is half of the number of slots mentioned above, with a maximum of about 22. When running, the brushes will short-circuit different commutator elements across different commutator segments 32, which will cause changes in the number of components in the circuit, resulting in torque fluctuations and current fluctuations.

[0093] Stall current of torque motor:

[0094] Ist=(U-ΔUb) / R

[0095] R≈(Nc×Rc) / 2

[0096] In the formula: Ist is the stall current, U is the stall voltage, ΔUb is the brush voltage drop, R is the armature resistance, Nc is the number of series components in a single branch, and Rc is the number of turns of a single component.

[0097] It is clear that the locked-rotor current will change when the number of series components changes, and its rate of change is approximately the rate of change of the short-circuit components. For an armature with a maximum of 22 components in series, a change in one brush will cause a change of about 5%, while a change in two brushes may exceed the requirement of 10% (200mA) of the locked-rotor current. Therefore, it is relatively difficult to meet the current fluctuation index requirements using a solid slot design.

[0098] To solve the above problems, the number of pole slots in core 1 is Z, and the number of commutator segments 32 is K.

[0099] K = μZ, μ ≥ 1, where μ is a natural number.

[0100] When μ≥2, the motor rotor has a virtual slot structure.

[0101] By fixing the commutator segment 32 by the commutator 3, a virtual slot structure can be achieved where the number of commutator segments 32 is μ times the number of pole slots, while ensuring that the position of the commutator segment 32 is fixed. After increasing the number of virtual slots, the number of elements in the winding 2 increases by μ times. Under the same number of slots, the number of series elements will increase by μ times, and the corresponding current fluctuation is about 1 / μ times the number of real slots, which is greatly reduced.

[0102] In a preferred embodiment, a 10-pole, 32-slot configuration is selected, μ = 2, and the number of virtual slots is 64. This results in 32 components per branch. When the number of components changes by 2, the change rate is approximately 6.3%. 6.3% × 2.1A = 0.132A, which meets the requirement that the change rate should not exceed 0.2A.

[0103] The structure of the virtual slot commutator 3 mainly consists of commutator segments 32 machined from a silver-copper-nickel alloy plate AgCuNi20-2. The number of commutator segments 32 is twice the number of slots in the iron core 1. See Figure 6 The commutator segments 32 are evenly distributed in the circumferential direction and a ring commutator 3 is formed by pressing 4330 phenolic glass fiber plastic. The subsequent process does not require tooling to shape the commutator segments 32. The mold ensures that the commutator segments 32 are evenly distributed in the circumference and have good consistency.

[0104] Performance Comparison: Key Technical Indicators of Virtual Slot Micro-Torque Servo Motor and Ordinary Torque Motor

[0105]

[0106] Table 1

[0107] As shown in Table 1, commutator 3 has high mechanical strength, stable operation, and small torque and current fluctuations.

[0108] In a further embodiment of the second aspect, the inner wall of the commutator 3 is provided with a plurality of positioning parts 33 that are engaged with the pole slots. The positioning parts 33 are matched with the positions of the commutator segments 32. When the positioning parts 33 are inserted into the pole slots, the commutator segments 32 are located at a predetermined position above the pole slots.

[0109] The positioning part 33 is a rectangular protrusion whose side wall abuts against the inner wall of the pole groove.

[0110] The positioning part 33 has a trapezoidal protrusion or a triangular protrusion at the end away from the commutator segment 32, and the width of the end near the commutator segment 32 is greater than the width of the end away from the commutator segment 32.

[0111] In this embodiment, when μ = 1, and one pole slot is engaged with one commutator segment 32, the positioning part 33 is located below each commutator segment 32.

[0112] In this embodiment, when μ = 2, and one pole slot is engaged with two commutator segments 32, the positioning part 33 is located below the middle position of two adjacent commutator segments 32.

[0113] In this embodiment, when μ=3, and one pole slot is engaged with three commutator segments 32, a positioning part 33 is provided every two commutator segments 32, and the positioning part 33 is located below the commutator segments 32.

[0114] The positioning part 33, which mates with the position of the commutator segment 32, ensures that the position of the commutator segment 32 mates with the position of the pole slot during assembly, facilitating the connection between the commutator segment 32 and the enameled wire. By making one end of the positioning part 33 into a trapezoidal protrusion or a triangular protrusion, the commutator 3 can be guided during assembly.

[0115] In a further embodiment of the second aspect, a welding groove is provided at the end of the commutator 32 away from the fixing part 31, and the end of the enameled wire is received in the welding groove.

[0116] The side of the fixing part 31 closest to the iron core 1 is higher than the bottom wall of the welding groove.

[0117] The end of the commutator segment 32 away from the iron core 1 and the fixing part 31 has a stepped surface that is higher than the bottom wall of the welding groove.

[0118] The side of the fixing part 31 near the iron core 1 is higher than the bottom wall of the welding groove. This can be done before step S4 by bending the end of the enameled wire into the welding groove and then dripping epoxy resin material onto the end of the welding groove near the iron core 1 to seal the end of the welding groove near the iron core 1. This prevents the solder from flowing into the winding 2 when the enameled wire is welded to the commutator segment 32. The epoxy resin material here has a good barrier effect. In addition, there is a stepped surface on the outside of the commutator segment 32 that is higher than the bottom wall of the welding groove. The purpose of this design is to observe whether the solder quality in the welding groove is full and free of voids and cold solder joints.

[0119] In a further embodiment of the second aspect, the commutator 32 is also provided with a groove on the side of the fixing part 31.

[0120] In this embodiment, the groove portion can be Figure 5 The symmetrically arranged vertical V-shaped grooves shown can also be horizontal V-shaped grooves or oblique V-shaped grooves, or several circular grooves or rectangular grooves.

[0121] By providing a groove, the commutator segment 32 can be prevented from rotating or even falling off within the fixing part 31, making its connection structure with the fixing part 31 more stable.

[0122] As described above, although the invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the invention itself. Various changes in form and detail may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A method for machining an electric motor rotor, characterized in that, include: S1. Distribute several commutator segments (32) circumferentially within the forming mold; S2. Pouring shaping material into the shaping mold, so that the commutator segment (32) and the shaping material solidify in the mold to form an annular commutator (3), wherein the shaping mold is used to ensure the circumferential distribution of the commutator segment (32) in the commutator (3); S3. The commutator (3) is fitted as an integral component onto one end of the iron core (1) with winding (2), and then the commutator (3) is bonded and fixed to the iron core (1) with winding (2); S4. Before the commutator (3) is assembled, the end of the enameled wire that makes up the winding (2) extends a predetermined distance toward the commutator (3). After completing S3 and fixing the predetermined position of the commutator (3) and the iron core (1), the end of the enameled wire is bent toward the position of the corresponding commutator segment (32). Then the enameled wire of the winding (2) is welded and fixed to the commutator segment (32) to form the motor rotor. Also includes: S3-1. Before the commutator (3) is fitted onto one end of the iron core (1) which has windings (2), an insulating material is coated on the end face and inner wall of the commutator (3) near the iron core (1) to form an insulating layer; and / or S3-2. Before the commutator (3) is fitted onto one end of the iron core (1) which has windings (2), an insulating material is coated on the end face and outer wall of the iron core (1) near the commutator (3) to form an insulating layer; S3-3. Based on S3-1 and / or S3-2, the commutator (3) is fitted onto one end of the iron core (1) with winding (2), and the shaping material and insulating material are heated to bond and fix the commutator (3) to the iron core (1). It also includes: assembly molds (4), The assembly mold (4) includes: a base (41), The positioning cylinder (42) is connected to the base (41); The central column (43) is connected to the base (41) and housed in the positioning cylinder (42), and its coaxiality with the positioning cylinder (42) is within a predetermined range; The positioning cylinder (42) has a frustum cavity that communicates with the outside. The inner diameter of the frustum cavity at the end near the base (41) is smaller than the inner diameter at the end away from the base (41). In S2, one end of the machined commutator (3) is shaped like a frustum ring; In S3, the iron core (1) with winding (2) is first fitted onto the center post (43), and then the frustum-shaped end of the commutator (3) is fitted onto the iron core (1) with winding (2), so that the outer wall of the frustum-shaped commutator (3) abuts against the inner wall of the frustum cavity of the positioning cylinder (42). Then, the commutator (3) is bonded and fixed to the iron core (1) with winding (2). After the commutator (3) and the iron core (1) are taken out from the assembly mold (4), the outer side of the commutator (3) is surface-shaped so that the outer shape and size of the commutator (3) match the outer shape and size of the iron core (1).

2. The method for machining a motor rotor according to claim 1, characterized in that, Also includes: S3-4. In S3, the outer side of the commutator (3) is surface-shaped so that the outer shape and size of the commutator (3) match the outer shape and size of the iron core (1). S3-5. Perform surface coating reinforcement treatment on the commutator (3).

3. The method for machining a motor rotor according to claim 1, characterized in that, Also includes: Before S3, an adhesive part (11) in the shape of a frustum ring is formed at one end of the iron core (1) with winding (2) using adhesive material; An annular ramp that mates with the adhesive part (11) is provided at one end of the inner side of the commutator (3); In S3, when the commutator (3) is fitted onto one end of the iron core (1) with the winding (2), the annular ramp inside the commutator (3) abuts against the adhesive part (11).

4. A motor rotor produced using the motor rotor processing method according to claim 1, characterized in that, include: Iron core (1), which has a through cavity inside and several pole slots outside; The winding (2) consists of several enameled wires wound around the pole slot; The commutator (3) also includes a fixing part (31) with one end sleeved on the iron core (1) and a plurality of commutator segments (32) inserted into the other end of the fixing part (31); The end of the commutator (32) away from the fixing part (31) is connected to the enameled wire.

5. The motor rotor produced by the motor rotor processing method according to claim 4, characterized in that, The number of pole slots in the iron core (1) is Z, and the number of commutator segments (32) is K. K = μZ, μ ≥ 1, where μ is a natural number.

6. The motor rotor produced by the motor rotor processing method according to claim 4, characterized in that, The inner wall of the commutator (3) is provided with a plurality of positioning parts (33) that are engaged with the pole slots. The positioning parts (33) are matched with the position of the commutator segment (32). When the positioning part (33) is inserted into the pole slot, the commutator segment (32) is located at a predetermined position above the pole slot. The positioning part (33) is a rectangular protrusion whose side wall abuts against the inner wall of the pole groove; The positioning part (33) is provided with a trapezoidal protrusion or a triangular protrusion at the end away from the commutator segment (32), and the width of the end near the commutator segment (32) is greater than the width of the end away from the commutator segment (32).

7. The motor rotor produced by the motor rotor processing method according to claim 4, characterized in that, The commutator segment (32) has a welding groove at one end away from the fixing part (31), and the end of the enameled wire is received in the welding groove; The side of the fixing part (31) near the iron core (1) is higher than the bottom wall of the welding groove; The commutator segment (32) has a stepped surface at one end away from the iron core (1) and the fixing part (31) that is higher than the bottom wall of the welding groove.

8. The motor rotor produced by the motor rotor processing method according to claim 4, characterized in that, The commutator segment (32) is housed in a groove on the side of the fixing part (31).

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