A starter armature assembly and method of manufacture
By employing an arrangement of enameled wires with different materials for the inner and outer layers in the starter armature assembly, the problems of core magnetic saturation and mechanical performance caused by replacing pure copper wire with copper-clad aluminum wire were solved. This achieved cost reduction and maintenance of motor performance, while ensuring the feasibility of processing and structural compatibility.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HUBEI SHENDIAN AUTOMOBILE ELECTRIC MOTORS CO LTD
- Filing Date
- 2026-04-09
- Publication Date
- 2026-07-07
Smart Images
Figure CN122348636A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of starter armature technology, and specifically to a starter armature assembly and its manufacturing method. Background Technology
[0002] The starter armature assembly is the core component of an automotive starter, typically consisting of an armature shaft, commutator, iron core, slot insulation, and multiple enameled wires. During operation, current flows through the commutator into the enameled wires, causing the armature assembly to rotate under the influence of an external magnetic field, thereby outputting torque to start the engine.
[0003] To reduce manufacturing costs, in recent years, the field has begun to explore the use of copper-clad aluminum wire instead of pure copper wire as the armature winding material. For example, prior art (US20170338611A1) discloses a cold metal transition welding method for copper and aluminum components in a starter motor, which mentions that the armature winding can be welded to the copper commutator segments using aluminum wire (including copper-clad aluminum wire or pure aluminum wire). However, simply replacing pure copper wire with copper-clad aluminum wire presents a series of technical challenges: On the one hand, since aluminum has a higher resistivity than copper, the wire diameter must be increased to ensure that the resistance remains unchanged and to avoid performance degradation. However, increasing the wire diameter will reduce the width of the iron core teeth. When the tooth width is less than the critical value, the iron core strength decreases and magnetic saturation is likely to occur, which will significantly affect the peak torque of the motor. On the other hand, copper-clad aluminum wire has poor mechanical properties and its bending resistance is weaker than that of pure copper wire. The traditional U-bending and splitting forming process and the integrated wiring topology of inner and outer layers (i.e., one enameled wire passes through both inner and outer layers at the same time) used in armature windings are difficult to apply to the increased copper-clad aluminum wire. Forced processing can easily lead to wire breakage or enamel film damage, making reliable mass production impossible.
[0004] To address the aforementioned issues, existing technologies have not yet proposed an armature assembly solution that can simultaneously reduce costs by introducing copper-clad aluminum wire, avoid core magnetic saturation, ensure processing feasibility, and maintain original performance and structural compatibility. Specifically, how to achieve cost optimization without altering other starter motor components, while maintaining the minimum core width to meet critical requirements, by using conductors of different materials and diameters for the inner and outer layers, and designing matching wiring topologies and processing techniques, is a pressing technical challenge in this field. Summary of the Invention
[0005] This invention proposes a starter armature assembly that solves the core technical problem of how to arrange conductors of different materials and diameters in the inner and outer layers without changing the magnetic circuit performance of the iron core when introducing copper-clad aluminum wire into the starter armature assembly to reduce costs.
[0006] The technical solution of this invention is implemented as follows:
[0007] A starter armature assembly, comprising:
[0008] Armature shaft;
[0009] The commutator is fixedly mounted on the armature shaft;
[0010] An iron core is fixedly mounted on the armature shaft, and the iron core has multiple slots distributed circumferentially.
[0011] Slot insulation is provided within the slots of the iron core;
[0012] Enamelled wire, disposed in the slot insulation, includes a first enamelled wire and a second enamelled wire;
[0013] The first enameled wire, which is pure copper wire, is disposed in the inner layer of the slot of the iron core; the second enameled wire, which is copper-clad aluminum wire, is disposed in the outer layer of the slot of the iron core, and the diameter of the second enameled wire is larger than that of the first enameled wire; the wiring topology of the first enameled wire and the second enameled wire on the tail side is a cross-wire connection in the same layer.
[0014] Furthermore, the bare wire diameter of the first enameled wire is φ2.0mm, and the bare wire diameter of the second enameled wire is φ2.5mm.
[0015] Furthermore, the copper-aluminum area ratio of the second enameled wire is 10%:90%.
[0016] Furthermore, the outer diameter of the iron core is φ52mm, the height is 33mm, and the number of slots is 28.
[0017] Furthermore, the narrowest part of the iron core has a width greater than 2.0 mm.
[0018] Furthermore, the tail height of the first enameled wire and the second enameled wire is 9.0 mm.
[0019] Furthermore, the first enameled wire and the second enameled wire are CNC 2D bending and 3D contouring mold forming structures, and the bending radius is greater than the wire diameter.
[0020] Furthermore, the first enameled wire and the second enameled wire swap the positions of their inner and outer layers every other slot on the twisting side.
[0021] A method for manufacturing a starter armature assembly includes the following steps: S1. CNC 2D bending process is used to process pure copper wire and copper-clad aluminum wire to form the preset shape; S2. Place the bent pure copper wire and copper-clad aluminum wire into a 3D molding die for forming, so that the bending radius of the copper-clad aluminum wire is greater than its wire diameter. S3. Place the formed pure copper wire in the inner layer of the iron core groove, and place the formed copper-clad aluminum wire in the outer layer of the iron core groove. S4. Add a twisting process before the twisting process, so that the inner and outer layer wires are swapped every other slot on the twisting side. After twisting, the pure copper wire and copper-clad aluminum wire are connected to the commutator.
[0022] Furthermore, in step S3, the tail height remains unchanged at 9.0 mm.
[0023] The beneficial effects of the technical solution provided in this application are as follows: 1. This application overcomes the technical limitation that the inner and outer layers of the armature assembly must be the same wire, which makes it impossible to achieve the arrangement of thinner inner and thicker outer layers, by setting the first enameled wire in the inner layer of the iron core slot as pure copper wire and the second enameled wire in the outer layer of the iron core slot as copper-clad aluminum wire with a wire diameter larger than that of the first enameled wire, and by adopting the same layer cross-wire connection for the inner and outer enameled wires on one side of the tail. This allows the application to replace only the outer layer wire with copper-clad aluminum wire, so that the resistance after the outer layer wire is thickened is basically equivalent to that of the original pure copper wire, thus maintaining the armature assembly performance unchanged, and avoiding the magnetic saturation and peak torque reduction problems caused by the reduction of the width of the iron core teeth below the critical value due to the overall thickening of the wire diameter. 2. Furthermore, by preferably using a first enameled wire diameter of 2.0 mm and a second enameled wire diameter of 2.5 mm, with a copper-aluminum area ratio of 10%:90%, the resistance per unit length of the outer copper-clad aluminum wire is 97.2% of that of the inner pure copper wire. This achieves the critical requirement that the narrowest part of the iron core is greater than 2.0 mm while ensuring resistance matching. CAE simulation verification shows that the peak torque of this improved scheme is almost equal to that of the original scheme, while the peak torque of the rejected scheme of simultaneously thickening both the inner and outer wires decreases by 6.7%, fully demonstrating the non-obviousness of this specific parameter combination. Attached Figure Description
[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0025] Figure 1 This is a schematic diagram of the armature assembly of the present invention;
[0026] Figure 2 This is a schematic diagram of the overall armature component analysis of the present invention;
[0027] Figure 3 A schematic diagram of the traditional enameled wire assembly design.
[0028] Figure 4 This is a schematic diagram of the enameled wire assembly design of the improved scheme of the present invention;
[0029] Figure 5 A top-view diagram of the traditional enameled wire layout;
[0030] Figure 6 This is a top view schematic diagram of the enameled wire layout of the improved scheme of the present invention;
[0031] Figure 7 A schematic diagram of the assembly state of enameled wire in a traditional scheme;
[0032] Figure 8 This is a schematic diagram of the assembly state of the enameled wire in the improved scheme of the present invention;
[0033] Figure 9 A schematic diagram showing the height dimensions of the enameled wire tail section in a traditional design.
[0034] Figure 10 This is a schematic diagram showing the height of the tail section of the first enameled wire in the improved embodiment of the present invention;
[0035] Figure 11 This is a schematic diagram showing the height of the tail section of the second enameled wire in the improved embodiment of the present invention;
[0036] Figure 12 This is a CAE simulation comparison chart of the present invention.
[0037] In the diagram: 1 Armature shaft; 2 Commutator; 3 Iron core; 4 Slot insulation; 5 Enamelled wire; 51 First enamelled wire; 52 Second enamelled wire; 6 Brazing filler; 7 Collar; 8 Insulating varnish. Detailed Implementation
[0038] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0039] like Figure 1 and Figure 2As shown, this embodiment provides a starter armature assembly, which includes an armature shaft 1, a commutator 2, an iron core 3, slot insulation 4, enameled wire 5, brazing filler 6, a collar 7, and insulating varnish 8. The armature shaft 1 is the core support of the entire armature assembly, with its front and rear ends forming support cylindrical surfaces for mating with external bushings, allowing the armature assembly to have only one degree of freedom of rotation about its axis. A gear is provided at the front end of the armature shaft 1 for outputting speed and torque; the middle section of the armature shaft 1 has knurled grooves for press-fitting and fixing the iron core 3; and the rear cylindrical surface of the armature shaft 1 is used for press-fitting and fixing the commutator 2.
[0040] Commutator 2 is fixedly press-fitted onto the rear cylindrical surface of armature shaft 1. Multiple copper busbars are provided on commutator 2, and external carbon brushes are pressed against the copper busbars of commutator 2. During operation, current flows in from the positive brush, through the copper busbars of commutator 2, into the enameled wire 5, and then flows out from the other end of the enameled wire 5 through the copper busbars on the other side of commutator 2 from the negative brush, forming a complete current loop.
[0041] The iron core 3 is fixedly press-fitted onto the knurled position in the middle section of the armature shaft 1. The iron core 3 is made of multiple layers of steel sheets to reduce eddy current losses. The outer diameter of the iron core 3 is 52 mm, and the height is 33 mm. 28 slots are evenly spaced along its circumference to accommodate the slot insulation 4 and the enameled wire 5. The function of the iron core 3 is to fix the slot insulation 4 and the enameled wire 5, and to conduct the magnetic field generated by the external magnetic poles, allowing the armature assembly to rotate under force after being energized.
[0042] There are 28 slot insulators 4, which are respectively set in the 28 slots of the iron core 3. Each slot insulator 4 wraps around the enameled wire 5, separating the iron core 3 from the enameled wire 5, and serving to insulate and protect the enameled wire 5.
[0043] like Figure 4 As shown, the core improvement of this embodiment lies in the structural design of the enameled wire 5. There are a total of 28 enameled wires 5, 14 first enameled wires 51 and 14 second enameled wires 52, respectively arranged in the 28 slots of the iron core 3. Each first enameled wire 51 occupies the inner layer of two slots at both ends, with a gap of 5 slots; each second enameled wire 52 occupies the outer layer of two slots at both ends, with a gap of 5 slots, as shown... Figure 6As shown in the diagram. The first enameled wire 51 is pure copper wire with a bare wire diameter of 2.0 mm; the second enameled wire 52 is copper-clad aluminum wire with a bare wire diameter of 2.5 mm. The diameter of the second enameled wire 52 is larger than that of the first enameled wire 51. The copper-aluminum area ratio of the second enameled wire 52 is 10%:90%, meaning that copper accounts for 10% and aluminum accounts for 90% of its cross-sectional area. Calculations show that the resistance per unit length of the second enameled wire 52 is 0.0052 Ω / m, which is essentially equivalent to the resistance per unit length of the first enameled wire 51 (0.00535 Ω / m), with the latter being 97.2% of the former. Therefore, replacing the original pure copper wire with the second enameled wire 52 will not cause an increase in resistance, thus ensuring that the performance of the armature assembly remains unchanged.
[0044] like Figure 4 As shown, to avoid narrowing of the teeth of the iron core 3 due to thickening of the second enameled wire 52, this embodiment only replaces the outer conductor with copper-clad aluminum wire with a bare wire diameter of 2.5mm, while the inner conductor remains pure copper wire with a bare wire diameter of 2.0mm. Figure 11 As shown, blue represents the original scheme, red represents the improved scheme of this application, and green represents the rejected improved scheme. CAE simulation verification shows that, while maintaining the narrowest width of core 3 greater than 2.0mm, the peak torque of the improved scheme is almost equal to that of the original scheme. If both the inner and outer layer conductors are thickened to 2.5mm, the narrowest width of core 3 will decrease to 1.5mm, resulting in a 6.7% decrease in peak torque. Therefore, this embodiment achieves material replacement and cost optimization by using different wire diameters for the inner and outer layers, while ensuring that the narrowest width of core 3 meets the critical requirement of being greater than 2.0mm.
[0045] To achieve the arrangement of conductors with different diameters in the inner and outer layers, the wiring topology of the enameled wire 5 was redesigned in this embodiment. For example... Figure 3 , Figure 5 , Figure 7 As shown, in a traditional starter armature assembly, a single enameled wire passes through both the inner and outer layers, meaning the inner and outer layers are the same conductor, and is soldered on one side of the commutator 2. This structure cannot achieve the arrangement of a thin inner wire and a thick outer wire. Figure 6 As shown, this embodiment changes the wiring topology of the inner and outer enameled wires on one side of the tail to a same-layer cross-wire connection. That is, the inner layer conductors are connected to each other within the same layer, and the outer layer conductors are connected to each other within the same layer. From a topological perspective, this wiring method is equivalent to the traditional method. Figure 10 As shown in / 11, although the outer wire is thickened by 0.5mm after adopting this wiring scheme, the tail height of the enameled wire 5 is still maintained at 9.0mm after optimization, which is consistent with the original structure. Therefore, the armature assembly can be directly applied to the existing starter without adjusting other parts of the starter, thus achieving good structural compatibility.
[0046] To achieve the aforementioned same-layer cross-wire wiring topology, this embodiment improves the processing technology of the enameled wire 5. Since copper-clad aluminum wire has relatively weak bending resistance, the supplier recommends that the bending radius must be greater than the wire diameter. Furthermore, the traditional U-bending and splitting forming process can only produce a simple shape with three bends, which cannot meet the complex wire shape required in this embodiment. Therefore, this embodiment uses a CNC 2D bending and 3D molding process to process the enameled wire 5. Specifically, firstly, the pure copper wire and copper-clad aluminum wire are bent using a CNC 2D bending process to form a preset two-dimensional shape; then, the bent wire is placed in a 3D molding mold for forming, ensuring that all bending radii are greater than the wire diameter, thereby preventing breakage or enamel damage to the copper-clad aluminum wire during processing. After 2D bending and 3D forming, the enameled wire 5 can form a complex wire shape that meets the requirements, with bending radii all greater than 2.5mm, satisfying the process requirements of copper-clad aluminum wire.
[0047] To achieve complete application of the same-layer cross-wire connection topology in the armature assembly, this embodiment adjusts the twisting process. In traditional winding configurations, the inner and outer layers of the conductors are exchanged on the tail side, but not on the twisting side. In this embodiment, since the tail side uses a same-layer cross-wire connection, the inner and outer layers of the conductors are not exchanged on the tail side. Therefore, the inner and outer layers need to be exchanged every other slot on the twisting side. To achieve this winding configuration and avoid interference, this embodiment adds a torsion process before the twisting process. This torsion process allows the inner and outer layer conductors to be exchanged every other slot on the twisting side, thus ensuring that the improved winding configuration is topologically equivalent to the traditional winding configuration.
[0048] There are 28 brazing fillers 6, which are placed between the enameled wire 5 and the commutator 2 to weld the enameled wire 5 and the copper busbar of the commutator 2 together to achieve electrical connection. A collar 7 is placed on the outside of the solder joint between the enameled wire 5 and the commutator 2 to fix the solder joint and prevent it from being thrown apart by centrifugal force. Insulating varnish 8 is filled in the gaps between the iron core 3, the slot insulation 4, and the enameled wire 5, as well as at the intersections where the enameled wire 5 protrudes from the iron core 3, and also between the enameled wire 5 and the collar 7. This serves to fix the enameled wire 5, prevent it from being thrown apart by centrifugal force, and also provides insulation protection.
[0049] First, CNC 2D bending process is used to process pure copper wire and copper-clad aluminum wire separately to form a preset two-dimensional shape. Then, the bent pure copper wire and copper-clad aluminum wire are placed in a 3D molding die for shaping, so that all bending radii of the copper-clad aluminum wire are greater than its wire diameter. Next, the shaped pure copper wire is placed in the inner layer of slot 3 of the iron core, and the shaped copper-clad aluminum wire is placed in the outer layer of slot 3 of the iron core. After ensuring that the tail height of the enameled wire 5 remains unchanged at 9.0mm, a twisting process is added before the twisting process, so that the inner and outer layer conductors are swapped every other slot on the twisting side.
[0050] Actual verification shows that the starter armature assembly using the technical solution of this embodiment has the same product quality and performance as the original solution. Only the armature assembly itself has been changed, and the other parts of the starter have not changed. Calculated based on the copper and aluminum prices in January 2026, the cost of each starter has decreased by 3 yuan (including the additional processing cost of copper-clad aluminum wire), achieving a significant cost optimization effect.
[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A starter armature assembly, characterized in that, include: Armature shaft (1); The commutator (2) is fixedly mounted on the armature shaft (1); The iron core (3) is fixedly mounted on the armature shaft (1), and the iron core (3) has multiple slots distributed along the circumference. Slot insulation (4) is provided in the slot of the iron core (3); Enamelled wire (5), disposed in the slot insulation (4), includes a first enamelled wire (51) and a second enamelled wire (52); The first enameled wire (51) is a pure copper wire, which is located in the inner layer of the slot of the iron core (3); the second enameled wire (52) is located in the outer layer of the slot of the iron core (3), which is a copper-clad aluminum wire, and the wire diameter of the second enameled wire (52) is larger than that of the first enameled wire (51); the wiring topology of the first enameled wire (51) and the second enameled wire (52) on the tail side is a cross-wire connection in the same layer.
2. The starter armature assembly as described in claim 1, characterized in that, The bare wire diameter of the first enameled wire (51) is φ2.0mm, and the bare wire diameter of the second enameled wire (5) is φ2.5mm.
3. The starter armature assembly according to claim 2, characterized in that, The copper-aluminum area ratio of the second enameled wire (52) is 10%:90%.
4. The starter armature assembly according to claim 1, characterized in that, The outer diameter of the iron core (3) is φ52mm, the height is 33mm, and the number of slots is 28.
5. The starter armature assembly according to claim 1, characterized in that, The narrowest part of the iron core (3) is wider than 2.0 mm.
6. The starter armature assembly according to claim 1, characterized in that, The tail height of the first enameled wire (51) and the second enameled wire (52) is 9.0 mm.
7. The starter armature assembly according to claim 1, characterized in that, The first enameled wire (51) and the second enameled wire (52) are CNC 2D bending and 3D contour forming structures, and the bending radius is greater than the wire diameter.
8. The starter armature assembly according to claim 1, characterized in that, The first enameled wire (51) and the second enameled wire (52) swap the inner and outer layers every other slot on the twisting side.
9. A method for manufacturing a starter armature assembly, characterized in that, Includes the following steps: S1. CNC 2D bending process is used to process pure copper wire and copper-clad aluminum wire to form the preset shape; S2. Place the bent pure copper wire and copper-clad aluminum wire into a 3D molding die for forming, so that the bending radius of the copper-clad aluminum wire is greater than its wire diameter. S3. Place the formed pure copper wire in the inner layer of the iron core (3) groove, and place the formed copper-clad aluminum wire in the outer layer of the iron core (3) groove. S4. Before the twisting process, a twisting process is added so that the inner and outer wires are swapped every other slot on the twisting side. After the twisting, the pure copper wire and the copper-clad aluminum wire are connected to the commutator (2).
10. The method for manufacturing the starter armature assembly according to claim 9, characterized in that, In step S3, the tail height remains unchanged at 9.0 mm.