Rotor assembly for suppressing electromagnetic interference of motor and motor with rotor assembly

Abstract

The utility model discloses a rotor assembly for suppressing electromagnetic interference of a motor and the motor with the rotor assembly. The rotor assembly comprises a rotor, a printed circuit board, a commutator and a rotating shaft, the rotor, the commutator and the printed circuit board are sleeved on the rotating shaft; the printed circuit board is arranged at the front end of the rotor and located between the rotor and the commutator. The printed circuit board is provided with an electromagnetic interference suppression element, the rotor and the printed circuit board are sleeved on the rotating shaft, and the printed circuit board is provided with an electromagnetic interference suppression element and a commutator. Compared with the prior art, the electromagnetic interference is reduced, the structure is compact, and the layout is reasonable.

Description

Technical Field

[0001] The utility model relates to the field of motors, in particular to a rotor component for suppressing electromagnetic interference of motors and a motor with the rotor component. Background Art

[0002] Brushed motors are widely used in power tools, model making, auto parts, household appliances and other fields, but the electromagnetic compatibility (EMC) problem of brushed motors is more prominent. Electromagnetic compatibility refers to the ability of a device or system to work normally in an electromagnetic environment without causing intolerable electromagnetic interference to other devices in the environment. Due to its working principle, DC brushed motors generate sparks between the brushes and the commutator, thereby generating electromagnetic interference (EMI), which can only be minimized or suppressed but not completely eliminated.

[0003] Conventional means in the prior art usually directly add capacitors and inductors inside the brush holder. However, in some occasions, such as high operating voltage, high speed, difficult commutation, strict electromagnetic interference requirements, etc., conventional means of adding capacitors and inductors inside the brush holder seem to be a drop in the bucket. Not only does the suppression effect fail to meet the standard, but also the space is limited, the installation is inconvenient, and the accumulation of carbon powder seriously affects the reliability and service life of the motor. For example, the Chinese utility model patent with application number 201821147698.X (authorization announcement number CN208638120U) discloses a hollow cup brushed motor rotor bracket, including an injection molded disk and a printed circuit board, the printed circuit board is fixed in the injection molded disk by injection molding, and one side of the printed circuit board is provided with multiple pads along the edge of the printed circuit board, and the other side of the printed circuit board is provided with a number of arc-extinguishing capacitors, and two adjacent arc-extinguishing capacitors are connected by conductors. The utility model adopts an arc-extinguishing capacitor, and the commutator, output shaft, injection molded disk, printed circuit board and arc-extinguishing capacitor are fixed by integral injection molding of a mold. The utility model has the following defects: the capacitor is fixed by injection molding, which requires many assembly steps, and the mold and the injection molding plate occupy a certain space, requiring the motor to have a larger size. Utility Model Content

[0004] The first technical problem to be solved by the utility model is to provide a rotor component with a compact structure for suppressing electromagnetic interference of a motor in view of the above technical status quo.

[0005] The second technical problem to be solved by the present invention is to provide a motor including a rotor with a compact structure for suppressing electromagnetic interference of the motor in view of the above-mentioned technical status quo.

[0006] The technical solution adopted by the utility model to solve the first technical problem mentioned above is: a rotor composition for suppressing electromagnetic interference of a motor, characterized in that: it includes a rotor, a printed circuit board, a rotating shaft and a commutator; the rotor, the printed circuit board and the commutator are all sleeved on the rotating shaft; the printed circuit board is arranged at the front end of the rotor and is located between the rotor and the commutator; an electromagnetic interference suppression element is provided on the printed circuit board.

[0007] Preferably, the commutator has a plurality of commutator segments, the pins of the commutator segments are connected to a printed circuit board, the number of the electromagnetic interference suppression elements is b, the number of the commutator segments is p, b and p are natural numbers greater than 1, and b / p=0.15-1.

[0008] When the b / p ratio is larger, the number of electromagnetic interference suppression components is larger and the suppression effect is better, but the difficulty of manufacturing and assembly processes will increase, resulting in increased costs. If the b / p ratio is too low, it is difficult to achieve the effect of suppressing electromagnetic interference. Therefore, b / p is controlled to be 0.15-1.

[0009] Preferably, the electromagnetic interference suppression element is one or more of a capacitor and a varistor.

[0010] In order to position the printed circuit board when assembling the rotor or the motor, preferably, a positioning groove is provided on the periphery of the printed circuit board.

[0011] In order to facilitate the installation of the printed circuit board, preferably, a soldering pad is provided on the printed circuit board, and the electromagnetic interference suppression element is soldered on the soldering pad.

[0012] In order to optimize the electromagnetic interference suppression element on the printed circuit board, the printed circuit board is annular and is arranged coaxially with the rotor.

[0013] The technical solution adopted by the utility model to solve the second technical problem is: a motor having the above-mentioned rotor component.

[0014] Compared with the prior art, the advantages of the utility model are: a printed circuit board is provided in the rotor assembly, the pins of the commutator segments are connected to the printed circuit board, and an electromagnetic interference suppression element is connected to the printed circuit board, thereby overcoming the large amount of electromagnetic interference generated by the motor spark to the outside, and there are fewer parts, achieving simple assembly steps, compact structure and reasonable layout. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of Example 1;

[0016] Figure 2 is a schematic diagram of a printed circuit board of Example 1;

[0017] Figure 3 This is a schematic diagram of the connection between the electromagnetic interference suppression element and the commutator of Example 1;

[0018] Figure 4 is the disturbance power of Example 1;

[0019] Figure 5 This is a schematic diagram of the connection between the electromagnetic interference suppression element and the commutator of Example 2;

[0020] Figure 6 is the disturbance power of Example 2;

[0021] Figure 7 is the disturbance power of comparative example 1. DETAILED DESCRIPTION

[0022] The present invention will be described in further detail below in conjunction with the accompanying drawings.

[0023] Example 1

[0024] like Figure 1-4 Shown is a preferred embodiment of the utility model.

[0025] The rotor for suppressing electromagnetic interference of the motor comprises a rotor 1, a printed circuit board 2, a wind wheel 3, a rotating shaft 4 and a commutator 5. The rotor 1, the wind wheel 3, the printed circuit board 2 and the commutator 5 are sequentially sleeved on the rotating shaft, the wind wheel 3 is arranged between the printed circuit board 2 and the rotor 1, and the printed circuit board 2 is arranged at the front end of the rotor 1 and between the rotor 1 and the commutator 5. An electromagnetic interference suppression element is arranged on the printed circuit board 2, and the commutator has a plurality of commutator segments 51, and the pins 52 of the commutator segments 51 are connected to the printed circuit board 2. The number of electromagnetic interference suppression elements is b, and the number of commutator segments 51 is p, and b / p=0.15-1. In this embodiment, the electromagnetic interference suppression element is a capacitor 21, and in other embodiments, a varistor 22 or the like can also be used.

[0026] A positioning groove 23 is provided on the periphery of the printed circuit board 2. A soldering pad is provided on the printed circuit board 2, and the electromagnetic interference suppression element is soldered on the soldering pad to be connected to the printed circuit board 2. The printed circuit board 2 is disc-shaped, and a center hole is provided at the center of the printed circuit board 2, and is coaxially arranged with the rotor 1.

[0027] like Figure 3 As shown, in this embodiment, p=24, b=8, that is, b / p=1 / 3, an electromagnetic interference suppression element is connected across three commutator segments 51 to form a C-type filter, resistors are provided at both ends of the filter, and an external power supply can be connected according to the needs of the motor type.

[0028] This embodiment also provides a motor having the above rotor composition. The disturbance power of the motor is tested according to the national standard GB4343. The result is as follows: Figure 4shown.

[0029] Example 2

[0030] The difference between this embodiment and embodiment 1 is that: Figure 5 As shown, in this embodiment, a varistor 22 is connected in parallel to the capacitor 21 as another electromagnetic interference suppression element. The disturbance power of the motor in this embodiment is tested according to the national standard GB4343. The result is as follows: Figure 6 shown.

[0031] Comparative Example 1

[0032] The difference between this comparative example and Example 1 is that the electromagnetic interference suppression element of the comparative example 1 is arranged on the motor brush holder instead of being arranged at the front end of the rotor 1. The disturbance power of the motor of this comparative example is tested according to the national standard GB4343. The result is as follows: Figure 7 As shown. Figure 4 , Figure 6 and Figure 7 It can be seen that the disturbance power dB quasi-peak value QP measured by the motor of comparative example 1 has exceeded the standard, while the dB value of embodiment 1 is reduced compared with the comparative example, and the electromagnetic interference of the motor of embodiment 1 is significantly suppressed; the dB value of embodiment 2 is lower than that of comparative example 1, the electromagnetic interference of the motor is better suppressed, and it is safer when used.

Claims

1. A rotor assembly for suppressing electromagnetic interference of a motor, characterized in that: The invention comprises a rotor (1), a printed circuit board (2), a rotating shaft (4) and a commutator (5); the rotor (1), the printed circuit board (2) and the commutator (5) are all sleeved on the rotating shaft (4); the printed circuit board (2) is arranged at the front end of the rotor (1) and between the rotor (1) and the commutator (5); and an electromagnetic interference suppression element is arranged on the printed circuit board (2).

2. The rotor assembly for suppressing electromagnetic interference of a motor according to claim 1 is characterized in that: The commutator (5) has a plurality of commutator segments (51), the pins (52) of the commutator segments (51) are connected to a printed circuit board (2), the number of the electromagnetic interference suppression elements is b, the number of the commutator segments (51) is p, b and p are natural numbers greater than 1, and b / p=0.15-1.

3. The rotor assembly for suppressing electromagnetic interference of a motor according to claim 1 is characterized in that: The electromagnetic interference suppression element is one or more of a capacitor (21) and a varistor (22).

4. The rotor assembly for suppressing electromagnetic interference of a motor according to claim 1 is characterized in that: The outer periphery of the printed circuit board (2) is provided with a positioning groove (23) for positioning the circuit board (2).

5. The rotor assembly for suppressing electromagnetic interference of a motor according to claim 1 is characterized in that: The printed circuit board (2) is provided with a soldering pad, and the electromagnetic interference suppression element is soldered on the soldering pad.

6. The rotor assembly for suppressing electromagnetic interference of a motor according to claim 1 is characterized in that: The printed circuit board (2) is annular and is arranged coaxially with the rotor (1).

7. The rotor assembly for suppressing electromagnetic interference of a motor according to claim 1 is characterized in that: It also comprises a wind wheel (3) sleeved on the rotating shaft, wherein the wind wheel (3) is arranged between the printed circuit board (2) and the rotor (1).

8. A motor, characterized in that: The invention comprises a rotor as claimed in any one of claims 1 to 7.

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