Single-phase motor for cooling fan

Abstract

The utility model discloses a single-phase motor stator and a motor for a cooling fan, the motor stator comprises a plurality of silicon steel sheets which are mutually overlapped and a plastic support which is integrally formed with the silicon steel sheets, the silicon steel sheets are radially and integrally formed with a plurality of pole arms, and the single-phase motor stator is characterized in that the pole arms are symmetrically designed along the central axis of the pole arms; the motor comprises a motor stator, a motor rotor located on the periphery of the motor stator, a coil and magnets, fan blades are arranged on the motor rotor, the coil is wound on pole arms of the motor stator, the magnets are arranged on the inner wall of the motor rotor, and the number of the pole arms of the motor corresponds to the number of the magnets. The pole arms of the motor stator are symmetrically designed, so that the vibration noise during rotation is reduced, and the positive and negative rotation switching can be easily realized. According to the utility model, the PWM circuit is connected to the control unit, and positive and negative rotation of the motor rotor is controlled through different input frequencies.

Description

Technical field:

[0001] The utility model relates to the technical field of cooling fan products, in particular to a single-phase motor stator for a cooling fan and an electronic motor using the same. Background technology:

[0002] The cooling fan is a necessary cooling device in electronic products. The motor currently used in the cooling fan is a brushless DC motor. The stator of the motor usually adopts a multi-pole structure, for example: the stator is made of stacked silicon steel sheets and has four pole arms evenly distributed. A coil is wound around each pole arm. The inner wall of the motor rotor with fan blades is provided with a corresponding magnet. When the coil is energized to generate an electromagnetic field, the electromagnetic field interacts with the magnet on the motor rotor to drive the motor rotor to rotate.

[0003] In order to facilitate the rotor starting, the pole arm of the current motor usually adopts an asymmetric design. Figure 1 As shown, this is a schematic diagram of a common single-phase four-pole motor rotor. The pole arm 1 of the silicon steel sheet constituting the motor rotor 10 adopts an asymmetric design. Specifically, the arc surface of the outer edge of the end of the pole arm 1 forms a height difference, wherein the thickness h1 of one end 11 is less than the thickness h2 of the other end 12. In this way, the electromagnetic field magnetic force generated by the silicon steel sheet can be made uneven. This uneven magnetic force will bias the rotor, thereby starting the rotor to rotate and avoiding the problem that the rotor is located in a dead angle and cannot be started smoothly. For example, see the invention patent application with Chinese patent application number: 200410062170.9, which discloses a "stator device for a motor", and the technical solution adopted is to design the silicon steel sheet pole arm of the motor into an asymmetric structure.

[0004] In addition, current motors can be designed in single-phase, two-phase, or three-phase. For three-phase motors, the number of pole arms of the rotor is 6, 9, 12, or multiples of 3. Three-phase motors can achieve forward and reverse rotation of the rotor, which is impossible for single-phase motors. Utility model content:

[0005] The utility model aims to improve the prior art and provide a single-phase multi-pole motor stator, namely a motor, for a heat dissipation fan.

[0006] In order to solve the above technical problems, a single-phase motor stator for a cooling fan in the utility model adopts the following technical solution: the motor stator includes: a plurality of silicon steel sheets stacked on each other, and a plastic bracket integrally formed with the silicon steel sheets, the silicon steel sheets are radially integrally formed with a plurality of pole arms, and the characteristic is that: the pole arms are symmetrically designed along their central axis.

[0007] Furthermore, in the above technical solution, an axial hole is formed at the center of the motor stator.

[0008] Furthermore, in the above technical solution, the number of the pole arms is any one of 6 poles, 9 poles, and 12 poles.

[0009] A single-phase motor for a cooling fan in the utility model adopts the following technical solution, which includes: a motor stator, a motor rotor located outside the motor stator, a coil, and a magnet, wherein the motor rotor is provided with fan blades, and the motor stator adopts the above-mentioned single-phase motor stator for a cooling fan; the coil is wound on the pole arm of the motor stator, the magnet is arranged on the inner wall of the motor rotor, and the number of the motor pole arm corresponds to the number of the magnets.

[0010] Furthermore, in the above technical solution, the motor is also provided with a Hall element, and when the motor stator and the motor rotor are in a non-rotating state, the Hall element is located between the two pole arms.

[0011] Furthermore, the above technical solution also includes a control unit, which includes: a current input terminal connected to an external power supply, a current output terminal connected to the coil, and a PWM input terminal. The Hall element is connected to the control unit, and the frequency of the input signal at the PWM input terminal changes to change the rotation direction of the motor rotor.

[0012] After adopting the above technical solution, the utility model has the following beneficial effects compared with the prior art:

[0013] 1. The number of pole arms in the motor stator of the utility model is 6, 9, 12, or multiples of 3. Its efficiency is higher than that of the traditional single-phase motor with 4 poles or 8 poles, and its operation is smoother with less vibration and noise.

[0014] 2. The pole arms of the motor stator of the utility model adopt a symmetrical design, so the electromagnetic field generated by the stator is evenly distributed, and the magnetic field generated by the magnets on the rotor is also uniform. The two rotate in coordination, and the magnetic field conversion is smooth, which not only reduces vibration and noise during rotation, but also allows easy forward and reverse switching.

[0015] 3. The utility model has a PWM circuit connected to the control unit to control the forward and reverse rotation of the motor rotor by different input frequencies. Description of the drawings:

[0016] Figure 1 is a schematic diagram of a rotor of an existing single-phase motor;

[0017] Figure 2 It is a three-dimensional diagram of the motor rotor of the utility model;

[0018] Figure 3 This is a front view of the motor rotor of the utility model;

[0019] Figure 4It is a schematic diagram of the motor of the utility model;

[0020] Figure 5 It is a circuit diagram of the control unit in the utility model. Specific implementation method:

[0021] The utility model is further described below in conjunction with specific embodiments and drawings.

[0022] See Figure 2 , Figure 3 As shown, the utility model is a single-phase multi-pole motor stator for a heat dissipation fan, and the motor stator 20 includes: a plurality of silicon steel sheets 21 and a plastic bracket 22. The silicon steel sheets 21 are stacked on each other, and then the plastic bracket 22 is formed by integral injection molding. All silicon steel sheets 21 are fixedly connected by the plastic bracket 22 to form a motor stator 20 with an axial hole 201 in the center.

[0023] Combination Figure 3 As shown, the silicon steel sheet 21 is radially integrally formed with a plurality of identical pole arms 210. In this embodiment, the number of the pole arms 210 is any one of 6 poles, 9 poles, and 12 poles. The pole arms 210 in the utility model are symmetrically designed along their central axis. As described in the background technology, after the silicon steel sheet adopts this design, the magnetic field generated by each group of pole arms 210 in the motor stator 20 is uniform.

[0024] See Figure 4 As shown, this is a single-phase motor for a heat dissipation fan in the utility model, which includes: the motor stator 20, the motor rotor 30 located outside the motor stator, the coil 40, and the magnet 50. The outer edge of the motor rotor 30 is provided with a fan blade 31, and the center of the motor rotor 30 is provided with a rotating shaft 32, and the rotating shaft 32 is matched with the shaft hole 201 in the motor rotor 20 through a bearing. When the motor rotor 30 rotates relative to the motor stator 20, the fan blade 31 rotates accordingly to generate a heat dissipation airflow.

[0025] The utility model adopts a single-phase design, the coil 40 is evenly wound on the pole arm 210 of the motor stator, the magnet 50 is arranged on the inner wall of the motor rotor 30, the magnet 50 adopts the same arc magnet, and the pole arm 210 of the motor corresponds to the number of magnets 50. Among them, the magnetic poles of two adjacent magnets 50 are in opposite directions to form an interlaced magnetic field, so that the fixed magnetic field of the magnet 50 on the motor rotor 30 is also evenly interlaced, which is used to realize the rotation of the motor rotor 30.

[0026] The pole arm 210 in the motor stator 20 of the utility model adopts a symmetrical design, so the dynamic magnetic field generated by it is uniform N / S pole. The dynamic magnetic field and the fixed magnetic field generated by the motor rotor 30 rotate together, and the magnetic field conversion is smoother and the operation vibration is smaller.

[0027] Since the pole arm 210 in the utility model adopts a symmetrical design and there is no height difference between the two ends of the pole arm 210, the dynamic magnetic field generated by it is uniform, which is prone to dead angle problems during startup. In order to facilitate starting the motor, the motor of the utility model is also provided with a Hall element 6. When the motor stator 20 and the motor rotor 30 are in a non-rotating state, the Hall element 6 is located between the two pole arms 210. Usually, the position of the Hall element 6 is slightly cheaper than the critical position. Its working principle is: the position of the motor rotor 30 is detected by the Hall element 6, and the control unit 7 of the motor switches the phase through the Hall signal, thereby smoothly driving the motor rotor 30 to run.

[0028] See Figure 5 As shown, the control unit 7 includes: a current input terminal 71 connected to an external power supply, a current output terminal 72 connected to the coil 40, a PWM input terminal 73, and a speed signal FG for controlling the speed of the motor rotor 30. The Hall element 6 is connected to the control unit 7, and the frequency of the input signal is changed through the PWM input terminal 73 to change the rotation direction of the motor rotor 30. Specifically, when the frequency of the input signal of the PWM input terminal 73 is a medium frequency (such as a few KHZ to tens of KHZ), the motor rotor 30 rotates forward to achieve a heat dissipation effect. When the frequency of the input signal of the PWM input terminal 73 is a high frequency (such as greater than 100KHZ), the motor rotor 30 reverses, and the dust removal of the fan blades 31 can be achieved.

[0029] The cooling fan motor of the utility model adopts a single-phase 6-pole / 9-pole / 12-pole pole arm design, which has higher efficiency than 4-pole / 8-pole motors, lower vibration and noise, and lower cost than three-phase motors. At the same time, the control unit 7 achieves the forward / reverse function of the motor fan through the different input frequencies of the PWM circuit, thereby achieving the purpose of reverse dust removal.

[0030] Of course, the above description is only a specific embodiment of the present invention and is not intended to limit the scope of implementation of the present invention. Any equivalent changes or modifications made according to the structure, characteristics and principles described in the patent application scope of the present invention should be included in the patent application scope of the present invention.

Claims

1. A single-phase motor for a cooling fan, comprising: A motor stator (20), a motor rotor (30) located outside the motor stator, a coil (40), and a magnet (50), wherein the motor rotor (30) is provided with a fan blade (31), characterized in that: The motor stator (20) comprises: a plurality of silicon steel sheets (21) stacked on each other, and a plastic bracket (22) integrally formed with the silicon steel sheets (21); the silicon steel sheets (21) are radially integrally formed with a plurality of pole arms (210); and the pole arms (210) are symmetrically designed along their central axis. The coil (40) is wound on the pole arm (210) of the motor stator, the magnet (50) is arranged on the inner wall of the motor rotor (30), and the number of the pole arm (210) of the motor corresponds to the number of the magnets (50).

2. A single-phase motor for a cooling fan according to claim 1, characterized in that: The motor is also provided with a Hall element (6). When the motor stator (20) and the motor rotor (30) are in a non-rotating state, the Hall element (6) is located between the two pole arms (210).

3. A single-phase motor for a cooling fan according to claim 2, characterized in that: It also includes a control unit (7), which includes: a current input terminal (71) connected to an external power supply, a current output terminal (72) connected to the coil (40), and a PWM input terminal (73). The Hall element (6) is connected to the control unit (7), and the rotation direction of the motor rotor (30) is changed by changing the frequency of the input signal through the PWM input terminal (73).

4. A single-phase motor for a cooling fan according to any one of claims 1 to 3, characterized in that: An axial hole (201) is formed at the center of the motor stator (20).

5. A single-phase motor for a cooling fan according to any one of claims 1 to 3, characterized in that: The number of the pole arms (210) is any one of 6 poles, 9 poles, and 12 poles.

Images