Rotor assembly of brushless motor

Abstract

The rotor assembly comprises a central shaft, a plastic magnetic block is arranged on the outer wall of the central shaft in an injection molding mode, a first bearing is connected to the position, close to the rear end, of the outer wall of the central shaft in an interference fit mode, and a second bearing is connected to the position, close to the middle, of the outer wall of the central shaft in an interference fit mode. A limiting groove is formed in the position, close to the middle, of the outer wall of the center shaft, an extending end sleeve is arranged at the center of the plastic magnetic block, a limiting block is fixedly connected to the middle of the inner wall of the extending end sleeve, the limiting block is arranged in the limiting groove in an injection molding mode, and the connecting firmness between the plastic magnetic block and the center shaft after injection molding is improved. According to the utility model, an iron core on the central shaft of a traditional rotor is abandoned, and the plastic magnetic block with a magnetic effect is directly injection-molded on the outer wall of the central shaft, so that the assembly cost is greatly reduced, the space of the rotor part is saved, glue and other bonding means are not needed, the reliability is improved, and the manufacturing cost is reduced; and the dynamic balance phase teaching original scheme is also greatly improved.

Description

Technical Field

[0001] The utility model relates to the technical field of brushless motor applications, in particular to a rotor assembly of a brushless motor. Background Art

[0002] With the rapid development of new energy, brushless motors have also developed rapidly relying on the new energy platform. With the increasing demand for motors with high comfort and long life, brushless motors have also been popularized.

[0003] Traditional brushless inner rotor motors use the method of axially pressing the iron core and surface-mounting magnetic materials on the outside of the iron core. This solution has cumbersome processes, low reliability, a relatively large overall volume, and requires the use of external equipment such as glue and ovens to help cure the magnetic tiles during the assembly process. Moreover, it is difficult to correct the dynamic balance, which easily leads to problems such as poor dynamic balance and large yaw of the motor rotor, and the manufacturing cost is relatively high. Therefore, the utility model proposes a rotor assembly of a brushless motor. Summary of the Utility Model

[0004] The technical problem to be solved by the utility model is to provide a rotor assembly of a brushless motor. By abandoning the iron core on the traditional rotor central shaft and directly injecting the plastic magnetic block with magnetic effect on the outer wall of the central shaft, the assembly cost is greatly reduced, the space of the rotor part is saved, and there is no need to use bonding means such as glue, which improves the reliability, reduces the manufacturing cost, and the dynamic balance has also been greatly improved compared with the original scheme.

[0005] To solve the above technical problem, a technical solution adopted by the utility model is: to provide a rotor assembly of a brushless motor, including a central shaft, a plastic magnetic block is injection-molded on the outer wall of the central shaft, a first bearing is interference-fitted on the outer wall of the central shaft near the rear end position, and a second bearing is interference-fitted on the outer wall of the central shaft near the middle position;

[0006] Wherein, a limiting groove is opened on the outer wall of the central shaft near the middle position, an extension end sleeve is arranged at the center of the plastic magnetic block, a limiting block is fixedly connected to the middle position of the inner wall of the extension end sleeve, and is injection-molded into the limiting groove through the limiting block to improve the connection firmness between the plastic magnetic block and the central shaft after injection molding.

[0007] The utility model is further arranged as: a connection groove is opened on the outer wall of the central shaft near the end face position, and a slotted hole is opened on the outer wall of the central shaft near the front end part.

[0008] Through the above technical solution, the connection groove can be fixed with an external connection shaft using a pin shaft, and the slotted hole can be used for connection and fixation during insertion.

[0009] The present utility model is further configured as follows: The plastic magnetic block is arranged in a covering manner. A plurality of grooves are evenly formed in the end face of the plastic magnetic block near the top. A plurality of surrounding columns are evenly fixedly connected to the inner wall of the plastic magnetic block. A plurality of reinforcing ribs are evenly fixedly connected to the inner arc wall of the plastic magnetic block. A boss is fixedly connected to the outer wall of the extension end sleeve located on the inner wall extension of the plastic magnetic block.

[0010] Through the above technical solution, it is convenient for the plastic magnetic block after injection molding to offset the weight of the internal weight-increasing boss and the reinforcing ribs with the weight-reducing grooves, so that the rotor can maintain dynamic balance during movement.

[0011] The present utility model is further configured as follows: A plurality of the surrounding columns are evenly radially distributed on the outer wall of the extension end sleeve and extend to the inner arc wall of the plastic magnetic block.

[0012] Through the above technical solution, it is convenient to improve the strength of the inner wall of the plastic magnetic block, and the balance of the rotation of the plastic magnetic block can be achieved under the action of the evenly distributed surrounding columns.

[0013] The present utility model is further configured as follows: The installation positions of a plurality of the reinforcing ribs are arranged opposite to the positions where a plurality of the grooves are formed, and the reinforcing ribs are in a cylindrical shape.

[0014] Through the above technical solution, a plurality of grooves can offset the weight after the reinforcing ribs are provided, so that the plastic magnetic block can maintain dynamic balance.

[0015] The present utility model is further configured as follows: The cross section of the boss is trapezoidal and is arranged opposite to the positions where a plurality of the grooves are formed.

[0016] Through the above technical solution, the entire rotor can be balanced and adjusted by the weight increase of the boss and the weight reduction of the grooves during rotation.

[0017] The present utility model is further configured as follows: The opposite surfaces of the first bearing and the second bearing are embedded in the end face fitting groove of the extension end sleeve through the raised portions provided thereon.

[0018] Through the above technical solution, after the first bearing and the second bearing are interference-connected with the central shaft, they can be stably connected to the plastic magnetic block, improving the stability during operation.

[0019] The beneficial effects of the present utility model are as follows:

[0020] A rotor assembly of a brushless motor proposed by the present utility model abandons the iron core on the traditional rotor central shaft, directly injects the plastic magnetic block with magnetic effect on the outer wall of the central shaft, greatly reduces the assembly cost, saves the space of the rotor part, and does not require bonding means such as glue, improves the reliability, reduces the manufacturing cost, and the dynamic balance is also greatly improved compared with the original scheme. Description of the Drawings

[0021] Figure 1 This is the first structural diagram of the rotor assembly of a brushless motor of the present utility model;

[0022] Figure 2 This is the second structural diagram of the rotor assembly of a brushless motor of the present utility model;

[0023] Figure 3 This is the exploded view of the rotor assembly of a brushless motor of the present utility model;

[0024] Figure 4 This is the first structural diagram of the plastic magnetic block in the rotor assembly of a brushless motor of the present utility model;

[0025] Figure 5 This is the second structural diagram of the plastic magnetic block in the rotor assembly of a brushless motor of the present utility model;

[0026] Figure 6 This is the structural diagram of the central shaft of the rotor assembly of a brushless motor of the present utility model.

[0027] In the figures: 100, central shaft; 101, limiting groove; 102, connecting groove; 103, slotted opening; 200, plastic magnetic block; 201, extended end sleeve; 202, groove; 203, surrounding column; 204, reinforcing rib; 205, boss; 206, limiting block; 300, first bearing; 400, second bearing. Detailed Description of the Preferred Embodiment

[0028] The following elaborates on the preferred embodiments of the present utility model in conjunction with the accompanying drawings, so that the advantages and features of the present utility model can be more easily understood by those skilled in the art, thereby making the protection scope of the present utility model more clearly defined.

[0029] As Figures 1-6As shown in the figure, a rotor assembly of a brushless motor includes a central shaft 100. A connection groove 102 is provided on the outer wall of the central shaft 100 near the end face position, and a slot 103 is provided on the outer wall of the central shaft 100 near the front end part. The connection groove 102 can be fixed to an external connection shaft using a pin shaft, and the slot 103 can be used for connection and fixation during insertion. A limit groove 101 is provided on the outer wall of the central shaft 100 near the middle position. An extension end sleeve 201 is provided at the center of the plastic magnetic block 200. A limit block 206 is fixedly connected to the middle position of the inner wall of the extension end sleeve 201, and is injection-molded into the limit groove 101 through the limit block 206 to improve the connection firmness between the plastic magnetic block 200 and the central shaft 100 after injection molding. A first bearing 300 is interference-fitted on the outer wall of the central shaft 100 near the rear end position, and a second bearing 400 is interference-fitted on the outer wall of the central shaft 100 near the middle position. The opposite surfaces of the first bearing 300 and the second bearing 400 are embedded in the end face fitting groove of the extension end sleeve 201 through the raised parts provided thereon, which is convenient for stably connecting the first bearing 300 and the second bearing 400 to the plastic magnetic block 200 after interference-fitting them with the central shaft 100, and improving the stability during operation.

[0030] As Figure 4 and Figure 5 shown in the figure, a plastic magnetic block 200 is injection-molded on the outer wall of the central shaft 100. The plastic magnetic block 200 is made of PP + samarium iron nitride material or PP + neodymium iron boron material. The plastic magnetic block 200 is arranged in a covering manner. A plurality of grooves 202 are evenly provided on the end face of the plastic magnetic block 200 near the top position. A plurality of surrounding columns 203 are evenly and fixedly connected to the inner wall of the plastic magnetic block 200. The plurality of surrounding columns 203 are evenly radially distributed on the outer wall of the extension end sleeve 201 and extend to the inner arc wall of the plastic magnetic block 200, which is convenient for improving the strength of the inner wall of the plastic magnetic block 200, and the plastic magnetic block 200 can rotate smoothly under the action of the evenly distributed surrounding columns 203. A plurality of reinforcing ribs 204 are evenly fixedly connected to the inner arc wall of the plastic magnetic block 200. The installation positions of the plurality of reinforcing ribs 204 are opposite to the positions where the plurality of grooves 202 are provided, and the reinforcing ribs 204 are arranged in a cylindrical shape, so that the weight after setting the reinforcing ribs 204 can be offset by the plurality of grooves 202, so that the plastic magnetic block 200 can maintain dynamic balance. A boss 205 is fixedly connected to the outer wall of the extension end sleeve 201 located on the inner wall of the plastic magnetic block 200, which is convenient for the plastic magnetic block 200 after injection molding to offset the weight of the inner weight-increasing boss 205 and the reinforcing ribs 204 with the weight-reducing grooves 202, so that the rotor can maintain dynamic balance during movement. The cross section of the boss 205 is trapezoidal and is opposite to the positions where the plurality of grooves 202 are provided, so that the entire rotor can adjust the balance by increasing the weight of the boss 205 and reducing the weight of the grooves 202 during rotation.

[0031] When the utility model is in operation, first place the central shaft 100 into the injection mold of the plastic magnetic block 200, and inject the plastic magnetic material into the mold, so that the plastic magnetic material is formed inside the mold. A part of the plastic magnetic material enters into the limiting groove 101 to form a limiting block 206, thereby being able to reinforce the plastic magnetic block 200 directly injection-molded on the central shaft 100, improving the firmness in use. And the plastic magnetic block 200 is provided with a weight offset setting between the convex platform 205 and the reinforcing rib 204 with increased internal weight and the groove 202 with reduced weight, so that the rotor can maintain dynamic balance during movement, improving the overall production efficiency.

[0032] The above are only the embodiments of the present utility model, and do not limit the patent scope of the present utility model accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present utility model, or directly or indirectly applied in other related technical fields, shall be similarly included in the patent protection scope of the present utility model.

Claims

1. A rotor assembly of a brushless motor, comprising a central shaft (100), characterized in that: The outer wall of the central shaft (100) is injection-molded with a plastic magnetic block (200). An interference fit connection is provided with a first bearing (300) at a position near the rear end of the outer wall of the central shaft (100), and an interference fit connection is provided with a second bearing (400) at a position near the middle of the outer wall of the central shaft (100). Among them, a limiting groove (101) is provided at a position near the middle of the outer wall of the central shaft (100). An extension end sleeve (201) is provided at the center of the plastic magnetic block (200). A limiting block (206) is fixedly connected to the middle position of the inner wall of the extension end sleeve (201), and the limiting block (206) is injection-molded inside the limiting groove (101).

2. The rotor assembly of a brushless motor according to claim 1, wherein: A connection groove (102) is provided at a position near the end face of the outer wall of the central shaft (100), and a slotted opening (103) is provided at a position near the front end part of the outer wall of the central shaft (100).

3. The rotor assembly of a brushless motor according to claim 1, characterized in that: The plastic magnetic block (200) is arranged in a covering manner. A plurality of grooves (202) are evenly provided at a position near the top of the end face of the plastic magnetic block (200). A plurality of surrounding columns (203) are evenly and fixedly connected to the inner wall of the plastic magnetic block (200). A plurality of reinforcing ribs (204) are evenly and fixedly connected to the inner arc wall of the plastic magnetic block (200). A boss (205) is fixedly connected to the outer wall of the extension end sleeve (201) located on the inner wall of the plastic magnetic block (200).

4. The rotor assembly of a brushless motor according to claim 3, wherein: The plurality of surrounding columns (203) are evenly radially distributed on the outer wall of the extension end sleeve (201) and extend to the inner arc wall of the plastic magnetic block (200).

5. The rotor assembly of a brushless motor according to claim 3, characterized in that: The installation positions of the plurality of reinforcing ribs (204) are arranged opposite to the positions where the plurality of grooves (202) are provided, and the reinforcing ribs (204) are arranged in a cylindrical shape.

6. The rotor assembly of a brushless motor according to claim 3, wherein: The cross-section of the boss (205) is trapezoidal and is arranged opposite to the positions where the plurality of grooves (202) are provided.

7. A rotor assembly of a brushless motor according to claim 1, characterized in that: The opposite surfaces of the first bearing (300) and the second bearing (400) are embedded in the mating groove of the end face of the extension end sleeve (201) through the protruding parts provided thereon.

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