Brush permanent magnet micromotor and assembling method

Abstract

The invention belongs to the technical field of motors, and particularly relates to a brush permanent magnet micromotor and an assembling method. In the brush permanent magnet micromotor, a first stator bracket is provided with a first mounting cavity, and the inner wall of the first mounting cavity is provided with a first supporting table; the first permanent magnet is installed in the first installation cavity and abuts against the first supporting table. A second mounting cavity is formed in the second stator bracket; a second supporting table is arranged on the inner wall of the second mounting cavity; the second permanent magnet is installed in the second installation cavity and abuts against the second supporting table. The magnetic conductive shell is sleeved on the first stator support and the second stator support. According to the invention, tolerances between the first permanent magnet and the magnetic conductive shell and between the second permanent magnet and the magnetic conductive shell are accumulated towards the outsides of the first supporting table and the second supporting table, so that magnetic gaps between the first permanent magnet and the iron core winding and between the second permanent magnet and the iron core winding can be reduced, and the magnetic efficiency and torque of the motor are improved, thereby reducing a driving current and improving the reliability of the motor. And the use amount of the permanent magnets and / or the iron cores and / or the copper wires can be reduced, and the consistency of products is also ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of motors, and particularly relates to a brushed permanent magnet micro-motor and an assembly method thereof. Background Art

[0002] A brushed permanent magnet motor generally consists of a housing, a permanent magnet, a rotor assembly and a rear end cover. The rotor assembly is composed of a motor shaft, an iron core winding and a commutator. A front bearing is sleeved on the front end of the housing. The permanent magnet is pasted or clamped on the inner wall of the housing by a circlip. The rotor assembly is installed in the housing, and the rear end cover is buckled on the housing. A rear bearing and a plastic part for installing a brush assembly are embedded in the rear end cover. The brush assembly is inserted into the plastic part, and the brush assembly keeps in contact with the commutator. One end of the motor shaft is installed on the rear bearing of the rear end cover, and the other end of the motor shaft is installed on the front bearing at the front end of the housing.

[0003] The permanent magnet is installed on the inner wall of the housing and needs to maintain a certain magnetic gap with the rotor assembly. In the prior art, the permanent magnet is usually fixed on the inner wall of the housing by a circlip. Due to the manufacturing tolerances of the permanent magnet and the housing, the manufacturing tolerances of the permanent magnet and the housing will accumulate from the inner wall of the housing to the inside. Moreover, the front bearing on the housing and the rear bearing of the rear end cover together support the rotor assembly, and it is also difficult to ensure concentricity. In order to ensure non-contact between the permanent magnet and the rotor assembly, it is necessary to increase the gap between the motor shaft and the bearing hole (if the gap is too small, it will be stuck when the front and rear bearings are not concentric), and increase the magnetic gap between the permanent magnet and the rotor assembly to ensure the normal operation of the brushed permanent magnet motor.

[0004] In order to ensure the coaxiality of the inner wall of the housing and the bearing holes at the front end of the housing and the machine shell, the housing is usually made of stretch metal material (stretch machine shell). However, the molds required for manufacturing the stretch machine shell have problems such as large volume, high cost, the need for large-tonnage punching presses, and low utilization rate of stretch materials. Moreover, due to the stress changes, the taper tolerance of the inner wall of the housing, and the concentricity tolerance between the inner wall of the housing and the bearing holes at the front end of the machine shell during the manufacturing process of the stretch machine shell, it is difficult to make the thickness uniform. The inner wall of the stretch machine shell cannot ensure coaxiality and fit with the magnetic tiles (i.e., there is also a gap between the magnetic tiles and the inner wall of the machine shell), so the magnetic gap between the permanent magnet and the rotor assembly cannot be reduced. The magnetic gap is generally between 0.25 - 0.4 mm. According to the formula: F = (μ0 / 4π) * [(m1 * m2) / r^2], where F represents the magnetic force (mutual repulsion or mutual attraction) between the magnets, μ0 is the magnetic permeability in a vacuum (constant), m1 is the magnetic moment of the first magnet (which can be set as the magnetic moment of the permanent magnet), m2 is the magnetic moment of the second magnet (which can be set as the magnetic moment generated by the iron core winding, and this magnetic moment is related to the driving current of the iron core winding, the iron core, the number of turns of the coil, and the wire diameter), and r is the distance between the two magnets, that is, the magnetic gap. Since the magnetic moment of the permanent magnet of the motor is a fixed value, and the magnetic moment generated by the rotor coil is related to the driving current and is proportional (when the driving current is the same, when the magnetic gap decreases, the load torque of the motor increases; when the load torque is the same, when the magnetic gap decreases, the driving current decreases. When meeting the driving requirements, the number of turns of the rotor coil and / or the wire diameter can also be reduced, saving copper wire, and / or reducing the amount of iron core used), so reducing the magnetic gap can effectively improve the magnetic efficiency and torque of the motor and can reduce resource occupancy. Summary of the Invention

[0005] An embodiment of the present invention provides a brushed permanent magnet micro-motor and an assembly method to solve the technical problems such as the inability to ensure the magnetic gap of the brushed permanent magnet motor in the prior art.

[0006] An embodiment of the present invention provides a brushed permanent magnet micro-motor, including a rotor mechanism and a stator mechanism; The rotor mechanism includes a motor shaft, and an iron core winding and a commutator both installed on the motor shaft; The stator mechanism includes a magnetic conductive shell, a first stator bracket, a second stator bracket, a first permanent magnet, a second permanent magnet, a first brush assembly, and a second brush assembly. The first stator bracket is provided with a first accommodation cavity, and the second stator bracket is provided with a second accommodation cavity; the first stator bracket is installed on the second stator bracket, and the rotor mechanism is installed in the first accommodation cavity and the second accommodation cavity; the first brush assembly is installed on the first stator bracket, the second brush assembly is installed on the second stator bracket, and both the first brush assembly and the second brush assembly are in contact with the commutator; The first stator bracket is further provided with a first installation cavity communicating with the first accommodation cavity, and a first supporting platform is arranged on the inner wall of the first installation cavity; the first permanent magnet is installed in the first installation cavity and abuts against the first supporting platform; The second stator bracket is further provided with a second installation cavity communicating with the second accommodation cavity, and a second supporting platform is arranged on the inner wall of the second installation cavity; the second permanent magnet is installed in the second installation cavity and abuts against the second supporting platform; The magnetic conductive shell is sleeved on the first stator bracket and the second stator bracket, and is arranged opposite to the first permanent magnet and the second permanent magnet.

[0007] Optionally, the rotor mechanism further includes a front bearing and a rear bearing sleeved on both ends of the motor shaft; The first stator bracket is further provided with a first front arc-shaped groove communicating with the first accommodation cavity and a first rear arc-shaped groove coaxial with the first front arc-shaped groove, and the second stator bracket is further provided with a second front arc-shaped groove communicating with the second accommodation cavity and a second rear arc-shaped groove coaxial with the second front arc-shaped groove; the front bearing is installed in the first front arc-shaped groove and the second front arc-shaped groove; the rear bearing is installed in the first rear arc-shaped groove and the second rear arc-shaped groove; The first supporting platform is a first arc-shaped convex platform coaxial with the first front arc-shaped groove, and the second supporting platform is a second arc-shaped convex platform coaxial with the second front arc-shaped groove.

[0008] Optionally, the first permanent magnet includes a first magnetic tile covering the first stator bracket, and the first magnetic tile abuts against the first arc-shaped convex platform; The second permanent magnet includes a second magnetic tile covering the second stator bracket, and the second magnetic tile abuts against the second arc-shaped convex platform.

[0009] Optionally, the magnetic conductive shell includes a first magnetic shell and a second magnetic shell connecting the first magnetic shell, and a joint is arranged at the connection of the first magnetic shell and the second magnetic shell; The joint, the first center line of the first permanent magnet and the second center line of the second permanent magnet are in the same plane.

[0010] Optionally, the first stator bracket and the second stator bracket are symmetrically distributed about the axis of the motor shaft; The first brush assembly and the second brush assembly are symmetrically distributed about the axis of the motor shaft; The first permanent magnet and the second permanent magnet are symmetrically distributed about the axis of the motor shaft; The first supporting platform and the second supporting platform are symmetrically distributed about the axis of the motor shaft; The first magnetic shell and the second magnetic shell are symmetrically distributed about the axis of the motor shaft.

[0011] Optionally, the magnetic conduction shell is formed by winding a flexible magnetic conduction material on the first stator bracket and the second stator bracket.

[0012] Optionally, the first stator bracket is provided with a first concave groove and a first convex block, and the second stator bracket is provided with a second convex block adapted to the first concave groove and a second concave groove adapted to the first convex block; Both the first brush assembly and the second brush assembly include a brush holder and a brush body mounted on the brush holder, and the brush body contacts the commutator; The first brush assembly is placed in the first concave groove and fixed by being pressed by the second convex block; the second brush assembly is placed in the second concave groove and fixed by being pressed by the first convex block.

[0013] Optionally, both the first brush assembly and the second brush assembly include a tongue provided on one side of the brush holder, and the tongue extends towards the core winding; both the first concave groove and the second concave groove are provided with a card slot adapted to the tongue, and the tongue is clamped in the card slot.

[0014] Optionally, the first stator bracket and / or the second stator bracket is provided with a ventilation groove, and the ventilation groove communicates the first accommodation cavity and the second accommodation cavity.

[0015] Another embodiment of the present invention further provides an assembly method, which is applied to the above-mentioned brushed permanent magnet micromotor, and includes: Both the core winding and the commutator are installed on the motor shaft; The first brush assembly is installed on the first stator bracket, and the second brush assembly is installed on the second stator bracket; The first stator bracket and the second stator bracket are spliced, so that the rotor mechanism is located in the first accommodation cavity and the second accommodation cavity, and both the first brush assembly and the second brush assembly are in contact with the commutator; The first permanent magnet is installed in the first installation cavity and abuts against the first support platform, and the second permanent magnet is installed in the second installation cavity and abuts against the second support platform; The magnetic conduction shell is sleeved on the first stator bracket and the second stator bracket.

[0016] In the present invention, a first mounting cavity is further provided on the first stator bracket, and a first supporting platform is provided on the inner wall of the first mounting cavity; the first permanent magnet is mounted in the first mounting cavity and abuts against the first supporting platform; a second mounting cavity is further provided on the second stator bracket, and a second supporting platform is provided on the inner wall of the second mounting cavity; the second permanent magnet is mounted in the second mounting cavity and abuts against the second supporting platform; the magnetic conductive shell is sleeved on the first stator bracket and the second stator bracket; the first stator bracket and the second stator bracket can be made of plastic, and the first stator bracket, the second stator bracket and the magnetic conductive shell can replace components such as a stretching machine case and a rear end cover, that is, the stator mechanism is assembled by a plurality of components, reducing the manufacturing cost of the stator mechanism.

[0017] In addition, when manufacturing the first stator bracket, only by ensuring the position accuracy of the first supporting platform, the magnetic gap between the first permanent magnet and the iron core winding can be ensured; when manufacturing the second stator bracket, only by ensuring the position accuracy of the second supporting platform, the magnetic gap between the second permanent magnet and the iron core winding can be ensured; the designs of the first supporting platform and the second supporting platform enable the tolerances between the first permanent magnet, the second permanent magnet and the magnetic conductive shell to accumulate towards the outer areas of the first supporting platform and the second supporting platform, thereby reducing the magnetic gap between the first permanent magnet, the second permanent magnet and the iron core winding, improving the magnetic efficiency and torque of the brushed permanent magnet micromotor, so that the driving current can be reduced, and the usage amount of the permanent magnet, and / or the iron core, and / or the copper wire of the iron core winding can be reduced, saving energy and reducing materials, and also ensuring the consistency of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can also obtain other drawings without creative efforts based on these drawings.

[0019] Figure 1 is a cross-sectional view of a brushed permanent magnet micromotor provided by an embodiment of the present invention; Figure 2 is an exploded structural schematic diagram of a brushed permanent magnet micromotor provided by an embodiment of the present invention; Figure 3 is a partial structural schematic diagram of a brushed permanent magnet micromotor provided by an embodiment of the present invention; Figure 4 is an exploded structural schematic diagram of a rotor mechanism provided by an embodiment of the present invention; Figure 5It is a schematic structural diagram of the first stator bracket of the brushed permanent magnet micromotor provided by an embodiment of the present invention; Figure 6 It is a schematic structural diagram of the first permanent magnet and the second permanent magnet installed in the magnetic conduction shell provided by an embodiment of the present invention; Figure 7 It is the front view of the brush assembly of the brushed permanent magnet micromotor provided by an embodiment of the present invention; Figure 8 It is a schematic structural diagram of the integral molding of the first stator bracket and the external housing provided by an embodiment of the present invention; Figure 9 It is a schematic structural diagram of two magnetic conduction shells of the brushed permanent magnet micromotor provided by an embodiment of the present invention; Figure 10 It is a schematic diagram of partial structures of the brushed permanent magnet micromotor in two directions provided by an embodiment of the present invention.

[0020] The reference numerals in the specification are as follows: 1. Rotor mechanism; 11. Motor shaft; 12. Iron core winding; 13. Commutator; 14. Front bearing; 15. Rear bearing; 2. Stator mechanism; 21. Magnetic conduction shell; 211. First magnetic shell; 212. Second magnetic shell; 213. Seam; 22. First stator bracket; 221. First accommodation cavity; 222. First installation cavity; 223. First support platform; 224. First front arc-shaped groove; 225. First depression groove; 226. Card slot; 227. First convex block; 228. First rear arc-shaped groove; 229. Ventilation groove; 2210. Welding convex; 23. Second stator bracket; 231. Second accommodation cavity; 232. Second installation cavity; 233. Second support platform; 234. Second front arc-shaped groove; 235. Second convex block; 237. Second depression groove; 238. Second rear arc-shaped groove; 24. First permanent magnet; 25. Second permanent magnet; 26. First brush assembly; 261. Brush holder; 262. Brush body; 263. Tongue; 27. Second brush assembly. Detailed implementation manners

[0021] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "longitudinal", "radial", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings. These are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the present invention. In the description of the present invention, unless otherwise specified, the meaning of "a plurality of" is two or more than two.

[0023] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "mounted", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] As Figures 1 to 3 shown, an embodiment of the present invention provides a brushed permanent magnet micro-motor, which includes a rotor mechanism 1 and a stator mechanism 2; As Figure 4 shown, the rotor mechanism 1 includes a motor shaft 11, and a core winding 12 and a commutator 13 both mounted on the motor shaft 11; it can be understood that a wire harness electrically connected to the commutator 13 is led out from the core winding 12.

[0025] As Figure 2 and Figure 5As shown in the figure, the stator mechanism 2 includes a magnetic conductive shell 21, a first stator bracket 22, a second stator bracket 23, a first permanent magnet 24, a second permanent magnet 25, a first brush assembly 26 and a second brush assembly 27. A first accommodation cavity 221 is provided on the first stator bracket 22, and a second accommodation cavity 231 is provided on the second stator bracket 23. The first stator bracket 22 is installed on the second stator bracket 23, and the rotor mechanism 1 is installed in the first accommodation cavity 221 and the second accommodation cavity 231. The first brush assembly 26 is installed on the first stator bracket 22, the second brush assembly 27 is installed on the second stator bracket 23, and both the first brush assembly 26 and the second brush assembly 27 are in contact with the commutator 13. It can be understood that the first accommodation cavity 221 and the second accommodation cavity 231 can be two semi-circular grooves, or can be arc grooves with different ratios. The first accommodation cavity 221 and the second accommodation cavity 231 accommodate the rotor mechanism 1. During the rotation of the rotor mechanism 1, the first brush assembly 26 and the second brush assembly 27 always maintain electrical connection with the commutator 13. Further explanation is that both the first stator bracket 22 and the second stator bracket 23 can be made of plastic.

[0026] A first installation cavity 222 communicating with the first accommodation cavity 221 is further provided on the first stator bracket 22. A first support platform 223 is provided on the inner wall of the first installation cavity 222. The first permanent magnet 24 is installed in the first installation cavity 222 and abuts against the first support platform 223. It can be understood that the first support platform 223 is provided on the inner wall of the first installation cavity 222 along the direction of the motor shaft 11. Further explanation is that there are two first support platforms 233, and the two first support platforms 233 are respectively provided on the inner walls at the front and rear ends of the first installation cavity 222.

[0027] A second installation cavity 232 communicating with the second accommodation cavity 231 is further provided on the second stator bracket 23. A second support platform 233 is provided on the inner wall of the second installation cavity 232. The second permanent magnet 25 is installed in the second installation cavity 232 and abuts against the second support platform 233. It can be understood that the second support platform 233 is provided on the inner wall of the second installation cavity 232 along the direction of the motor shaft 11. Further explanation is that there are two second support platforms 233, and the two second support platforms 233 are respectively provided on the inner walls at the front and rear ends of the second installation cavity 232.

[0028] The surfaces of the first permanent magnet 24 and the second permanent magnet 25 corresponding to each other have opposite magnetic polarities and the same dimensions.

[0029] The magnetic conductive shell 21 is sleeved on the first stator bracket 22 and the second stator bracket 23, and is arranged opposite to the first permanent magnet 24 and the second permanent magnet 25. It can be understood that the magnetic conductive shell 21 is in close contact with the first permanent magnet 24 and the second permanent magnet 25 for conducting magnetic fields; and the manufacturing process of the magnetic conductive shell 21 is simple, only requiring a small-tonnage machine tool and using a simple curling process for manufacturing. It has a high material utilization rate, uniform thickness, no taper tolerance, is in close contact with the first permanent magnet 24 and the second permanent magnet 25, and has a smaller gap due to the action of magnetic pulling force; further explained, by using a simple curling process to manufacture the magnetic conductive shell 21, materials with better magnetic conductivity can be used. Compared with a stretched machine shell, it has a uniform thickness, can also increase the thickness, has more material options, and has a better magnetic conduction effect, thereby improving the magnetic efficiency and reducing the drive current of the brushed permanent magnet micromotor.

[0030] In the present invention, a first installation cavity 222 is further provided on the first stator bracket 22, and a first support platform 223 is provided on the inner wall of the first installation cavity 222; the first permanent magnet 24 is installed in the first installation cavity 222 and abuts against the first support platform 223; a second installation cavity 232 is further provided on the second stator bracket 23, and a second support platform 233 is provided on the inner wall of the second installation cavity 232; the second permanent magnet 25 is installed in the second installation cavity 232 and abuts against the second support platform 233; the magnetic conductive shell 21 is sleeved on the first stator bracket 22 and the second stator bracket 23; the first stator bracket 22 and the second stator bracket 23 can be made of plastic, and the first stator bracket 22, the second stator bracket 23, and the magnetic conductive shell 21 can replace components such as a stretched machine shell, a rear end cover, and an embedded plastic part. Moreover, the stator mechanism 2 is assembled from multiple components, reducing the manufacturing cost of the stator mechanism 2.

[0031] In addition, when manufacturing the first stator bracket 22, it is only necessary to ensure the position accuracy of the first support platform 223 to ensure the magnetic gap between the first permanent magnet 24 and the iron core winding 12; when manufacturing the second stator bracket 23, it is only necessary to ensure the position accuracy of the second support platform 233 to ensure the magnetic gap between the second permanent magnet 25 and the iron core winding 12; the designs of the first support platform 223 and the second support platform 233 enable the tolerances between the first permanent magnet 24, the second permanent magnet 25 and the magnetic conduction shell 21 to accumulate towards the outer areas of the first support platform 223 and the second support platform 233, so that the magnetic gap between the first permanent magnet 24, the second permanent magnet 25 and the iron core winding 12 can be reduced, improving the magnetic efficiency and torque of the brushed permanent magnet micromotor. Therefore, the driving current can be reduced, and the usage amounts of the permanent magnet, and / or the iron core, and / or the copper wire of the iron core winding can be reduced, saving energy and materials and ensuring the consistency of the product.

[0032] Further, the magnetic gap of the brushed permanent magnet micromotor with a stretched housing is generally 0.25 - 0.4 mm. If the magnetic gap is taken as 0.3 mm; while the magnetic gap of the brushed permanent magnet micromotor designed with the first support platform 223 and the second support platform 233 can be reduced to 0.15 mm; according to the formula: F = (μ0 / 4π) * [(m1 * m2) / r^2], where F represents the magnetic force between the magnets (mutual repulsion or mutual attraction), μ0 is the magnetic permeability in vacuum (constant), m1 is the magnetic moment of the first magnet (which can be set as the magnetic moment of the permanent magnet), m2 is the magnetic moment of the second magnet (which can be set as the magnetic moment generated by the iron core winding, and this magnetic moment is related to the driving current of the iron core winding, the amount of iron core, the number of coil turns and the wire diameter), r is the distance between the two magnets, that is, the magnetic gap; the magnetic force is inversely proportional to the square of the magnetic gap; if only the magnetic gap is changed, it can be deduced that: the magnetic force F1 when the magnetic gap is 0.3 mm = 11.11 * (μ0 / 4π) * (m1 * m2), and the magnetic force F2 when the magnetic gap is 0.15 mm = 44.44 * (μ0 / 4π) * (m1 * m2), and F2 is 4 times that of F1. Thus, it can be seen that reducing the magnetic gap can greatly improve the torque of the motor. Therefore, if the torque does not need to be increased too much, the driving current can be reduced, and the usage amounts of the permanent magnet (i.e., m1 is reduced), and / or the iron core (i.e., m2 is reduced), and / or the copper wire of the iron core winding (i.e., m2 is reduced) can be reduced, saving energy and materials.

[0033] In one embodiment, as Figures 2 to 4 shown, the rotor mechanism 1 further includes a front bearing 14 and a rear bearing 15 sleeved on the motor shaft 11; it can be understood that the front bearing 14 is sleeved on the front end of the motor shaft 11, and the rear bearing 15 is sleeved on the rear end of the motor shaft 11.

[0034] The first stator bracket 22 is further provided with a first front arc-shaped groove 224 communicating with the first accommodation cavity 221 and a first rear arc-shaped groove 228 coaxial with the first front arc-shaped groove 224. The second stator bracket 23 is further provided with a second front arc-shaped groove 234 communicating with the second accommodation cavity 231 and a second rear arc-shaped groove 238 coaxial with the second front arc-shaped groove 234. The front bearing 14 is installed in the first front arc-shaped groove 224 and the second front arc-shaped groove 234 (the front bearing 14, the first front arc-shaped groove 224 and the second front arc-shaped groove 234 are coaxially arranged). The rear bearing 15 is installed in the first rear arc-shaped groove 228 and the second rear arc-shaped groove 238 (the rear bearing 15, the first rear arc-shaped groove 228 and the second rear arc-shaped groove 238 are coaxially arranged). It can be understood that the first front arc-shaped groove 224 and the second front arc-shaped groove 234 can be two semi-circular arc grooves, or arc grooves with different ratios. The first front arc-shaped groove 224 and the second front arc-shaped groove 234 form a circular hole, and the front bearing 14 is pressed into the circular hole. The first rear arc-shaped groove 228 and the second rear arc-shaped groove 238 can be two semi-circular arc grooves, or arc grooves with different ratios. The first rear arc-shaped groove 228 and the second rear arc-shaped groove 238 form a circular hole, and the rear bearing 15 is pressed into the circular hole. The front bearing 14 and the rear bearing 15 can support the motor shaft 11 from both ends.

[0035] The first support platform 223 is a first arc-shaped convex platform coaxial with the first front arc-shaped groove 224, and the second support platform 233 is a second arc-shaped convex platform coaxial with the second front arc-shaped groove 234. Further explained, the first arc-shaped convex platform and the first front arc-shaped groove 224 are coaxially arranged, the second arc-shaped convex platform and the second front arc-shaped groove 234 are coaxially arranged, and the relative positions of all parts on the first stator bracket 22 and the second stator bracket 23 are within the tolerance range. The molds for manufacturing the first stator bracket 22 and the second stator bracket 23 can adopt the inlay process in precision machining technology, use a three-coordinate measuring instrument to detect the coaxiality-related dimensions of the injection-molded parts, and ensure the coaxiality and relative positions within the tolerance range by fine-tuning the inlay parts, so as to ensure the consistency of the magnetic gap.

[0036] In this embodiment, the first arc-shaped boss and the first front arc-shaped groove 224 are coaxially arranged, and the second arc-shaped boss and the second front arc-shaped groove 234 are coaxially arranged, thereby ensuring the coaxiality among the first permanent magnet 24, the second permanent magnet 25, and the motor shaft 11. During the rotation of the motor shaft 11, the front bearing 14 and the rear bearing 15 are not easily deformed or damaged. Moreover, the first arc-shaped boss can ensure the magnetic gap between the first permanent magnet 24 and the iron core winding 12, and the second arc-shaped boss can ensure the magnetic gap between the second permanent magnet 25 and the iron core winding 12. Therefore, the magnetic gap of this brushed permanent magnet micromotor can be made relatively small, ensuring the efficiency of this brushed permanent magnet micromotor.

[0037] In one embodiment, as Figure 8 shown, the first stator bracket 22 and / or the second stator bracket 23 can be integrally formed with the outer shell of the application product, enhancing the fixing strength of the product, saving materials, reducing the installation steps of the application product, and reducing the cost of the application product.

[0038] Furthermore, as Figure 3 shown, a gasket is also sleeved on the motor shaft 11. The front bearing 14 and the rear bearing 15 are generally oil-impregnated bearings. The gasket can enclose the front bearing 14 in the first front arc-shaped groove 224 and the second front arc-shaped groove 234, and the gasket can also enclose the rear bearing 15 in the first rear arc-shaped groove 228 and the second rear arc-shaped groove 238. Thus, the lubricating oil of the front bearing 14 and the rear bearing 15 is enclosed, and the lubricating oil is not easily volatilized and dissipated, effectively reducing the friction generated during the rotation of the motor shaft 11, thereby reducing noise and prolonging the service life of this brushed permanent magnet micromotor.

[0039] In one embodiment, as Figure 1 and Figure 2 shown, the first permanent magnet 24 includes a first magnetic tile covering the first stator bracket 22, and the first magnetic tile abuts against the first arc-shaped boss. Understandably, the inner surface of the first magnetic tile is a first inner arc-shaped concave surface, and this first inner arc-shaped concave surface abuts against the first arc-shaped boss; the outer surface of the first magnetic tile is a first outer arc-shaped convex surface, and this first outer arc-shaped convex surface abuts against the magnetic conduction shell 21.

[0040] The second permanent magnet 25 includes a second magnetic tile covering the second stator bracket 23, and the second magnetic tile abuts against the second arc-shaped boss. Understandably, the inner surface of the second magnetic tile is a second inner arc-shaped concave surface, and this second inner arc-shaped concave surface abuts against the second arc-shaped boss; the outer surface of the second magnetic tile is a second outer arc-shaped convex surface, and this second outer arc-shaped convex surface abuts against the magnetic conduction shell 21.

[0041] In this embodiment, only by placing the first magnetic tile in the first installation cavity 222, the coaxiality with the motor shaft 11 can be ensured by relying on the first arc-shaped boss; only by placing the second magnetic tile in the second installation cavity 232, the coaxiality with the motor shaft 11 can be ensured by relying on the second arc-shaped boss; the magnetic attraction force of the first magnetic tile and the second magnetic tile enables the magnetic conductive shell 21 to be sleeved on the first stator bracket 22 and the second stator bracket 23; the assembly operation of this brushed permanent magnet micro-motor is simple.

[0042] In one embodiment, the number of the first installation cavities 222 on the first stator bracket 22 can be set to 2 or more. Correspondingly, the number of the first permanent magnets 24 installed in the first installation cavities 222 can also be set to 2 or more; similarly, the number of the second installation cavities 232 on the second stator bracket 23 can be set to 2 or more. Correspondingly, the number of the second permanent magnets 25 installed in the second installation cavities 232 can also be set to 2 or more; multiple first permanent magnets 24 and multiple second permanent magnets 25 are distributed at intervals to meet the requirements of a multi-pole brushed micro-motor.

[0043] In one embodiment, as Figure 6 shown, the magnetic conductive shell 21 includes a first magnetic shell 211 and a second magnetic shell 212 connecting the first magnetic shell 211, and a joint 213 is provided at the connection of the first magnetic shell 211 and the second magnetic shell 212; it can be understood that the first magnetic shell 211 and the second magnetic shell 212 can be attracted together only by the magnetic attraction force of the first magnetic tile and the second magnetic tile, or can be assembled together through a clamping structure, a buckling structure, etc.

[0044] The joint 213, the first median line L1 of the first permanent magnet 24, and the second median line L2 of the second permanent magnet 25 are in the same plane. In this embodiment, the joint between the first magnetic shell 211 and the second magnetic shell 212 is in the middle of the first permanent magnet 24 and the second permanent magnet 25, which will not affect the magnetic force lines from the N pole to the S pole of the first permanent magnet 24 and the second permanent magnet 25; and the first magnetic shell 211 and the second magnetic shell 212 are assembled into the magnetic conductive shell 21, and it is easy to sleeve the magnetic conductive shell 21 on the first stator bracket 22 and the second stator bracket 23.

[0045] In one embodiment, as Figure 1 and Figure 2As shown, the first stator bracket 22 and the second stator bracket 23 are symmetrically distributed about the axis of the motor shaft 11; the first brush assembly 26 and the second brush assembly 27 are symmetrically distributed about the axis of the motor shaft 11; the first permanent magnet 24 and the second permanent magnet 25 are symmetrically distributed about the axis of the motor shaft 11; the first support platform 223 and the second support platform 233 are symmetrically distributed about the axis of the motor shaft 11; the first magnetic shell 211 and the second magnetic shell 212 are symmetrically distributed about the axis of the motor shaft 11. In this embodiment, the first stator bracket 22 and the second stator bracket 23 are designed symmetrically, so that the first stator bracket 22 and the second stator bracket 23 can share a set of molds, reducing the manufacturing cost of the brushed permanent magnet micromotor; the symmetrical design of the first magnetic shell 211 and the second magnetic shell 212, and the symmetrical design of the first brush assembly 26 and the second brush assembly 27 further reduce the manufacturing cost of the brushed permanent magnet micromotor.

[0046] In one embodiment, the magnetic conductive shell 21 is formed by winding a flexible magnetic conductive material (for example, an ultra-thin silicon steel strip or an A3 steel strip with a thickness of 0.05 mm - 0.1 mm) on the first stator bracket 22 and the second stator bracket 23. In this embodiment, the magnetic conductive shell 21 is formed by winding a flexible magnetic conductive material on the first stator bracket 22 and the second stator bracket 23, ensuring the tightness of the magnetic conductive shell 21 and allowing the thickness of the magnetic conductive shell 21 to be adjusted according to actual needs.

[0047] In one embodiment, as Figure 9 shown, the magnetic conductive shell 21 can also be replaced by a ring-shaped magnetic conductive material with a single-sided opening and a seam 213, or an integral ring-shaped magnetic conductive material without an opening, and sleeved on the first stator bracket 22 and the second stator bracket 23.

[0048] In one embodiment, as Figure 3 and Figure 5 shown, the first stator bracket 22 is provided with a first recessed groove 225 and a first protrusion 227, and the second stator bracket 23 is provided with a second protrusion 235 adapted to the first recessed groove 225 and a second recessed groove 237 adapted to the first protrusion 227; it can be understood that on the first stator bracket 22 and the second stator bracket 23, there are corresponding recessed grooves and protrusions that are adapted to each other.

[0049] As Figure 7As shown, the first brush assembly 26 and the second brush assembly 27 both include a brush holder 261 and a brush body 262 mounted on the brush holder 261, the second protrusion 235 presses the brush holder 261 of the first brush assembly 26 into the first recessed groove 225, the first protrusion 227 presses the brush holder 261 of the second brush assembly 27 into the second recessed groove 237, and the brush bodies 262 of the first brush assembly 26 and the second brush assembly 27 both contact the commutator 13. Because of the central symmetric design, only one group is marked for description. It can be understood that the brush body 262 can be an elastic metal sheet directly in contact with the commutator 13, or an elastic metal sheet embedded with graphite particles, which contacts the commutator 13 through the graphite particles.

[0050] Specifically, the brush holder 261 of the first brush assembly 26 is placed in the first recessed groove 225, and the brush holder 261 of the second brush assembly 27 is placed in the second recessed groove 237; then the first stator bracket 22 and the second stator bracket 23 are assembled together, and the second protrusion 235 is inserted into the first recessed groove 225 and used to press the brush holder 261 of the first brush assembly 26 into the first recessed groove 225, thereby ensuring that the first brush assembly 26 is stably installed on the first stator bracket 22 and the second stator bracket 23. The first protrusion 227 is inserted into the second recessed groove 237 and is used to press the brush holder 261 of the second brush assembly 27 into the second recessed groove 237, thereby ensuring the stability of the second brush assembly 27 installed on the first stator bracket 22 and the second stator bracket 23; in addition, during the assembly of the brush permanent magnet micromotor, there is no need to move the brush body 262, and the commutator 13 is naturally pressed onto the brush body 262, further improving the convenience of assembling the brush permanent magnet micromotor. Due to the central symmetrical design, only one group is marked for description.

[0051] In one embodiment, the angle between the contact surface between the first stator bracket 22 and the second stator bracket 23 and the brush body 262 is 0°-15° (that is, the angle can be changed by changing the depth of the first recessed groove 225 and the contact surface in the groove where the brush holder 261 is placed); the brush body 262 made of different materials has different degrees of compression and bending, and thus has different angles; the angle can be set according to actual needs, and the normal commutation of the brush permanent magnet micromotor needs to be ensured. Because it is a centrally symmetrical design, only one group is marked for description.

[0052] In one embodiment, if Figure 3 and Figure 7As shown, both the first brush assembly 26 and the second brush assembly 27 include a tongue 263 disposed on one side of the brush holder 261, and the tongue 263 extends in the direction of the iron core winding 12; a clamping groove 226 adapted to the tongue 263 is provided in both the first recessed groove 225 and the second recessed groove 237, and the tongue 263 is clamped in the clamping groove 226. It can be understood that the second bump 235 presses the brush holder 261 of the first brush assembly 26 in the first recessed groove 225, and the tongue 263 of the first brush assembly 26 is clamped in the clamping groove 226 communicating with the first recessed groove 225; the first bump 227 presses the brush holder 261 of the second brush assembly 27 in the second recessed groove 237, and the tongue 263 of the second brush assembly 27 is clamped in the clamping groove 226 communicating with the second recessed groove 23, further ensuring the stability of the first brush assembly 26 and the second brush assembly 27 mounted on the first stator bracket 22 and the second stator bracket 23, and it is not easy for the first brush assembly 26 and the second brush assembly 27 to be displaced, and the generation of noise is also avoided; especially for a small-sized brushed permanent magnet micromotor, the side walls of the first recessed groove 225 for placing the first brush assembly 26 and the second recessed groove 237 for placing the second brush assembly 27 will be relatively thin, or even zero, and the tongue is more needed to fix the first brush assembly 26 and the second brush assembly 27.

[0053] In one embodiment, as Figure 2 and Figure 3 shown, the first stator bracket 22 and / or the second stator bracket 23 is provided with a ventilation groove 229, and the ventilation groove 229 is disposed on the side wall of the first stator bracket 22 along the motor shaft 11 direction near the first front arc groove 224 and / or the first rear arc groove 228, and / or is disposed on the side wall of the second stator bracket 22 along the motor shaft 11 direction near the second front arc groove 234 and / or the second rear arc groove 238. It can be understood that there are multiple ventilation grooves 229 and they can correspond to each other. As Figure 10 shown, after the first stator bracket 22 and the second stator bracket 23 are assembled, the corresponding ventilation grooves 229 form a ventilation hole along the motor shaft 11 direction, and the ventilation hole communicates the first accommodation cavity 221 and the second accommodation cavity 231, ensuring the heat dissipation performance during the operation of the rotor mechanism 1 and extending the service life of the brushed permanent magnet micromotor.

[0054] In one embodiment, as Figure 5As shown, a welding projection 2210 is provided on the joint surface between the first stator bracket 22 and the second stator bracket 23, and the first stator bracket 22 and the second stator bracket 23 are welded together through the welding projection 2210. It can be understood that the welding projection 2210 is provided on both the first stator bracket 22 and the second stator bracket 23, and the first stator bracket 22 and the second stator bracket 23 can be welded by ultrasonic welding.

[0055] An embodiment of the present invention further provides an assembly method, which is applied to the above-mentioned brushed permanent magnet micromotor, and includes: S100. Install the iron core winding 12 and the commutator 13 on the motor shaft 11. Specifically, first insert the motor shaft 11 into the iron core, and sleeved with insulating sheets on the motor shaft 11, and the iron core is located between the two insulating sheets; then sleeve the commutator 13 on the motor shaft 11; thereafter, wind enameled wire on the iron core to form the iron core winding 12, and weld the outgoing wire of the iron core winding 12 to the commutator 13; then, after sleeving a gasket on the motor shaft 11, sleeve the front bearing 14 and the rear bearing 15 on the motor shaft 11 respectively, thus completing the assembly of the rotor mechanism 1.

[0056] S200. Install the first brush assembly 26 on the first stator bracket 22, and install the second brush assembly 27 on the second stator bracket 23.

[0057] S300. Splice the first stator bracket 22 and the second stator bracket 23, and make the rotor mechanism 1 located in the first accommodation cavity 221 and the second accommodation cavity 231, and make both the first brush assembly 26 and the second brush assembly 27 contact with the commutator 13. Specifically, first, install the first brush assembly 26 and the second brush assembly 27 on the first stator bracket 22 and the second stator bracket 23 respectively; then, align the front bearing 14 of the rotor mechanism 1 and place it into the first front arc-shaped groove 224 or the second front arc-shaped groove 234, and align the rear bearing 15 and place it into the first rear arc-shaped groove 228 or the second rear arc-shaped groove 238; finally, splice the first stator bracket 22 and the second stator bracket 23, so that the rotor mechanism 1 is located in the first accommodation cavity 221 and the second accommodation cavity 231. Since there is no permanent magnet to generate magnetic attraction on the rotor mechanism 1 and the coaxiality is guaranteed, the assembly is more convenient, and the gap between the motor shaft 11 and the bearing hole can also be reduced, increasing the service life of the brushed permanent magnet micromotor; further, the first stator bracket 22 and the second stator bracket 23 can be fused together by ultrasonic welding process.

[0058] S400. Mount the first permanent magnet 24 in the first mounting cavity 222 and abut it against the first supporting platform 223, and mount the second permanent magnet 25 in the second mounting cavity 232 and abut it against the second supporting platform 233. Specifically, after applying glue to the sides of the first permanent magnet 24 and the second permanent magnet 25, mount the first permanent magnet 24 in the first mounting cavity 222, and bond the side of the first permanent magnet 24 to the inner wall of the first mounting cavity 222 along the motor shaft 11 direction. Then mount the second permanent magnet 25 in the second mounting cavity 232, and bond the side of the second permanent magnet 25 to the inner wall of the second mounting cavity 232 along the motor shaft 11 direction, thereby avoiding gaps and generating noise. The magnetic attraction force between the rotor mechanism and the first permanent magnet 24 and the second permanent magnet 25 further ensures that the inner surface of the first permanent magnet 24 fits on the first supporting platform 223, and the inner surface of the second permanent magnet 25 fits on the second supporting platform 233. Then, according to the magnetic polarities of the installed first permanent magnet 24 and second permanent magnet 25, mark the positive and negative power supply polarities of the first brush assembly 26 and the second brush assembly 27.

[0059] S400. Sleeve the magnetic conduction shell 21 on the first stator bracket 22 and the second stator bracket 23. It can be understood that when buckling the magnetic conduction shell 21, relying on the magnetic attraction force of the first permanent magnet 24 and the second permanent magnet 25 on the magnetic conduction shell 21, the magnetic conduction shell 21 is attracted and buckled on the peripheries of the first stator bracket 22 and the second stator bracket 23.

[0060] In the present invention, the assembly operation of the brushed permanent magnet micro-motor is simple, and the tolerances between the first permanent magnet 24, the second permanent magnet 25 and the magnetic conduction shell 21 accumulate towards the outer areas of the first supporting platform 223 and the second supporting platform 233. Thus, the magnetic gap between the first permanent magnet 24, the second permanent magnet 25 and the iron core winding 12 can be reduced, improving the magnetic efficiency and torque of the brushed permanent magnet micro-motor. Therefore, the driving current can be reduced, and the usage amount of the permanent magnet, and / or the iron core, and / or the copper wire of the iron core winding can be reduced, saving energy and reducing materials, and also ensuring the consistency of the product.

[0061] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A brushed permanent magnet micromotor, characterized in that, It includes a rotor mechanism and a stator mechanism; The rotor mechanism includes a motor shaft, and a core winding and a commutator both installed on the motor shaft; The stator mechanism includes a magnetic conductive shell, a first stator bracket, a second stator bracket, a first permanent magnet, a second permanent magnet, a first brush assembly and a second brush assembly. The first stator bracket is provided with a first accommodation cavity, and the second stator bracket is provided with a second accommodation cavity; The first stator bracket is installed on the second stator bracket, and the rotor mechanism is installed in the first accommodation cavity and the second accommodation cavity; The first brush assembly is installed on the first stator bracket, the second brush assembly is installed on the second stator bracket, and both the first brush assembly and the second brush assembly are in contact with the commutator; The first stator bracket is further provided with a first installation cavity communicating with the first accommodation cavity, and a first support platform is provided on the inner wall of the first installation cavity; The first permanent magnet is installed in the first installation cavity and abuts against the first support platform; The second stator bracket is further provided with a second installation cavity communicating with the second accommodation cavity, and a second support platform is provided on the inner wall of the second installation cavity; The second permanent magnet is installed in the second installation cavity and abuts against the second support platform; The magnetic conductive shell is sleeved on the first stator bracket and the second stator bracket, and is arranged opposite to the first permanent magnet and the second permanent magnet.

2. The brushed permanent magnet micromotor according to claim 1, wherein, The rotor mechanism further includes a front bearing and a rear bearing sleeved on both ends of the motor shaft; The first stator bracket is further provided with a first front arc-shaped groove communicating with the first accommodation cavity and a first rear arc-shaped groove coaxial with the first front arc-shaped groove, and the second stator bracket is further provided with a second front arc-shaped groove communicating with the second accommodation cavity and a second rear arc-shaped groove coaxial with the second front arc-shaped groove; The front bearing is installed in the first front arc-shaped groove and the second front arc-shaped groove; The rear bearing is installed in the first rear arc-shaped groove and the second rear arc-shaped groove; The first support platform is a first arc-shaped convex platform coaxial with the first front arc-shaped groove, and the second support platform is a second arc-shaped convex platform coaxial with the second front arc-shaped groove.

3. The brushed permanent magnet micromotor according to claim 2, characterized in that, The first permanent magnet includes a first magnetic tile covering the first stator bracket, and the first magnetic tile abuts against the first arc-shaped convex platform; The second permanent magnet includes a second magnetic tile covering the second stator bracket, and the second magnetic tile abuts against the second arc-shaped convex platform.

4. The brushed permanent magnet micromotor according to claim 1, characterized in that, The magnetic conductive shell includes a first magnetic shell and a second magnetic shell connecting the first magnetic shell, and a joint is provided at the connection of the first magnetic shell and the second magnetic shell; The joint, the first midline of the first permanent magnet and the second midline of the second permanent magnet are in the same plane.

5. The brushed permanent magnet micromotor according to claim 4, characterized in that, The first stator bracket and the second stator bracket are symmetrically distributed about the axis of the motor shaft; The first brush assembly and the second brush assembly are symmetrically distributed about the axis of the motor shaft; The first permanent magnet and the second permanent magnet are symmetrically distributed about the axis of the motor shaft; The first supporting platform and the second supporting platform are symmetrically distributed about the axis of the motor shaft; The first magnetic shell and the second magnetic shell are symmetrically distributed about the axis of the motor shaft.

6. The brushed permanent magnet micromotor according to claim 1, characterized in that, The magnetic conducting shell is formed by winding a flexible magnetic conducting material on the first stator bracket and the second stator bracket.

7. The brushed permanent magnet micromotor according to claim 1, characterized in that, The first stator bracket is provided with a first concave groove and a first convex block, and the second stator bracket is provided with a second convex block adapted to the first concave groove and a second concave groove adapted to the first convex block; Both the first brush assembly and the second brush assembly include a brush holder and a brush body mounted on the brush holder, and the brush body contacts the commutator; The first brush assembly is placed in the first concave groove and fixed by pressing with the second convex block; the second brush assembly is placed in the second concave groove and fixed by pressing with the first convex block.

8. The brushed permanent magnet micromotor according to claim 7, characterized in that, Both the first brush assembly and the second brush assembly include a tongue provided on one side of the brush holder, and the tongue extends in the direction of the iron core winding; clamping grooves adapted to the tongue are provided in both the first concave groove and the second concave groove, and the tongue is clamped in the clamping groove.

9. The brushed permanent magnet micromotor according to claim 1, characterized in that, The first stator bracket and / or the second stator bracket is provided with a ventilation groove, and the ventilation groove communicates the first accommodation cavity and the second accommodation cavity.

10. An assembly method, applied to the brushed permanent magnet micromotor according to any one of claims 1 to 9, characterized in that, Comprising: Mounting both the iron core winding and the commutator on the motor shaft; Mounting the first brush assembly on the first stator bracket and mounting the second brush assembly on the second stator bracket; Splicing the first stator bracket and the second stator bracket, and making the rotor mechanism located in the first accommodation cavity and the second accommodation cavity, and making both the first brush assembly and the second brush assembly contact the commutator; Mounting the first permanent magnet in the first mounting cavity and abutting against the first supporting platform, and mounting the second permanent magnet in the second mounting cavity and abutting against the second supporting platform; Sleeving the magnetic conducting shell on the first stator bracket and the second stator bracket.

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