LDS micro cooling module

Abstract

The present invention discloses an LDS micro heat dissipation module, which includes a top cover, a base, a back iron, a motor housing, a magnet, a stator winding and an impeller. The present invention improves the torque fluctuation and axial force fluctuation of the motor by optimizing the slot-pole matching of the motor, thereby reducing the vibration noise of the product and improving the sound quality of the product; and adopts the LDS process to make a three-dimensional conductive circuit on the base, which not only simplifies the traditional PFC structure and improves the aerodynamic noise, but also further reduces the axial thickness. At the same time, it is also very convenient to put all the components on the outside of the base, which is convenient for the mounting of electronic components, improves the processability and has good expansibility. The coil in the stator winding is wound with self-adhesive enameled wire, which can make full use of the space inside the motor, increase the slot full rate of the coil, increase the number of turns of the motor, and thus improve the efficiency of the motor. In addition, the VC plate and the fins are combined into a radiator, which has a good heat dissipation effect and effectively improves the temperature gradient of the chip.

Description

Technical Field

[0001] The present invention relates to the field of heat dissipation technology, and in particular to an LDS micro heat dissipation module. Background Art

[0002] As smart terminals such as laptops, tablets, and mobile phones tend to be thinner and lighter, the heat dissipation modules used to dissipate heat in terminal products are also becoming thinner and thinner, and the requirements for the sound quality of micro heat dissipation modules are becoming more and more stringent. Micro fans are the main sound source in micro heat dissipation modules. How to further improve the sound quality of micro fans has posed a great challenge to the fan industry.

[0003] According to research, the sound quality of the micro fan is not only related to the residual imbalance of the rotor, but also closely related to the vibration of the motor. From the source of vibration, the vibration source of the motor is divided into torque fluctuation and axial force fluctuation. Torque fluctuation is the main cause of vibration and noise in the motor. The torque fluctuation of the motor and its suppression technology have always been one of the research hotspots of brushless DC motors. Therefore, it is of great significance to study methods to reduce or suppress torque fluctuation.

[0004] For micro fans, due to limited space, the motor solutions currently used are relatively limited. The motor solutions for commercial micro fans are mainly the following:

[0005] 1. Radial flux motor. Due to limited size and space, a 4-slot 4-pole radial motor solution is generally used - Solution 1.

[0006] 2. Axial flux motor, also called disc motor. Due to the limited size and space, the ironless motor structure is often used. For the slot-pole matching of the stator and rotor, a 4-slot 4-pole single-phase motor - Scheme 2, or a 3-slot 4-pole three-phase motor - Scheme 3, or a 4-slot 6-pole two-phase motor - Scheme 4 is often used.

[0007] For Solution 1, this driving mode is a typical square wave voltage drive, which has fundamental torque fluctuations, and it is very difficult to suppress this torque fluctuation.

[0008] For solution 2, this driving mode is still a typical square wave voltage drive. In addition to the principle of torque fluctuation, this driving mode also has the problem of difficulty in starting. To solve this problem, a pre-eccentric positioning solution is often used, that is, a high magnetic permeability material is used to attract the rotor to a position that is easy to start. However, the introduction of high magnetic permeability materials will lead to additional problems. The presence of high magnetic permeability materials will produce additional cogging effects, causing cogging torque pulsation, which will further worsen the torque fluctuation.

[0009] For Solution 3, the motor with an odd number of slots (or an odd number of coils) in the stator naturally has unbalanced radial electromagnetic force, which will cause additional vibration and noise. Therefore, this solution is still not the best solution.

[0010] For scheme 4, the motor can be considered as two 6-slot 6-pole single-phase disc motors connected in parallel. For each single-phase motor, due to limited space, 2 coils are used to simulate the effect of 6 coils. In order to achieve the best torque fluctuation suppression effect and avoid causing unbalanced electromagnetic force, the two motors are staggered by 270° electrical angle. This scheme is the driving scheme of the commercial 4-slot 6-pole motor. In theory, this scheme has a good torque fluctuation suppression effect. However, due to the unevenness of the magnetic field waveform, the torque fluctuation generated by replacing 6 coils with 2 coils is still relatively large. After the two phases are superimposed, the torque fluctuation suppression effect will be weakened to a considerable extent. In addition, the commercial 4-slot 6-pole motor has block insulation material on the outside of its coil, which reduces the winding space and the magnetic flux of the stator coil turn chain, resulting in a decrease in motor efficiency.

[0011] Therefore, none of the above solutions are the best. In addition, for ultra-thin fans, the space that can be reduced in the axial dimension is extremely limited. If the FPC solution is used for connection, since the FPC itself is flexible, a reinforcement plate is generally required, which results in a limited reduction in the axial dimension of the fan solution using FPC. Secondly, the FPC and the fan frame are generally fixed by adhesive, which has limited strength.

[0012] To this end, it is necessary to develop an LDS micro heat dissipation module that can improve aerodynamic noise and further reduce the axial thickness. Summary of the invention

[0013] In view of the above-mentioned deficiencies, the object of the present invention is to provide a LDS micro heat dissipation module with a reasonable structural design, which can improve aerodynamic noise and has a thin thickness.

[0014] To achieve the above purpose, the technical solution provided by the present invention is:

[0015] A LDS micro heat dissipation module comprises a top cover, a base, a back iron, a motor housing, a magnet, a stator winding and an impeller. A three-dimensional conductive circuit is formed on the surface of the base by an LDS process. The stator winding is arranged on the base and connected to the three-dimensional conductive circuit. A middle tube is provided at the base corresponding to the center position of the stator winding. The motor housing is rotatably arranged on the middle tube. The magnet is arranged on the motor housing at a position corresponding to the stator winding. The impeller is sleeved on the motor housing. The top cover is arranged on the base. The stator winding is a three-phase six-slot four-pole, three-phase six-slot eight-pole or two-phase four-slot six-pole disc motor stator winding to reduce unbalanced radial magnetic pull.

[0016] As a preferred solution of the present invention, a tongue is provided on the outer wall of the base, and a gold finger is formed on the surface of the tongue through the LDS process. The gold finger is connected to the three-dimensional conductive circuit, and the gold finger is convenient for adapting to the connector, so that the assembly is simple and convenient.

[0017] As a preferred solution of the present invention, the coil in the stator winding is wound with self-adhesive enameled wire to fully utilize the space inside the motor, increase the slot fill rate of the coil, increase the number of turns of the motor, and thus improve the efficiency of the motor.

[0018] As a preferred solution of the present invention, the coil in the stator winding is in the shape of a rounded trapezoid to increase the magnetic flux of the coil and thereby improve the efficiency of the motor.

[0019] As a preferred solution of the present invention, a rounded trapezoidal boss adapted to the coil is provided on the inner bottom surface of the base, which cooperates well with the coil, improves the positioning accuracy of the coil, and reduces the difficulty of assembling the coil.

[0020] As a preferred solution of the present invention, a concave cavity for arranging the stator winding is provided on the inner bottom surface of the base, so as to avoid protrusion of the stator winding and reduce aerodynamic noise.

[0021] As a preferred solution of the present invention, an annular boss is provided on the base corresponding to the outer side of the periphery of the middle tube, a concave cavity is formed between the annular boss and the middle tube, the stator winding is arranged in the concave cavity, and a slope is provided on the outer side of the annular boss to transition to the inner bottom surface of the base, so that the air duct between the base and the blades is more in line with the principles of fluid mechanics, and the aerodynamic noise can be reduced by more than 1.5dBA.

[0022] As a preferred solution of the present invention, the outer bottom surface of the base is provided with an annular groove adapted to the back iron, and the back iron is arranged in the annular groove, so that the distance between the back iron and the three-dimensional conductive circuit is significantly increased, thereby effectively improving the antistatic level. In addition, the back iron is moved to the outer bottom surface of the base, so that the joint between the base and the middle tube is moved upward, the structural rigidity of the middle tube is improved, the vibration is reduced, and the assembly of the back iron is also made easier. Since the fan size is very small, it is not as convenient to assemble the back iron from the inside as from the outside.

[0023] As a preferred solution of the present invention, a heat sink is provided at the air duct position of the base, and the heat sink includes a VC board and fins provided on the VC board, which has good heat dissipation effect and effectively improves the temperature gradient of the chip. The VC board is fixed to the base by soldering and has good stability.

[0024] As a preferred solution of the present invention, the base and the middle tube are made of integrally formed LDS plastic, which has a firm connection and good structural stability.

[0025] As a preferred solution of the present invention, ultrasonic or laser welding is adopted between the top cover and the base, which has a good sealing effect and improves the waterproof performance.

[0026] The beneficial effects of the present invention are as follows: the present invention has a reasonable structural design, and by optimizing the slot-pole matching of the motor, the torque fluctuation and axial force fluctuation of the motor are improved, thereby reducing the vibration noise of the product, improving the sound quality of the product, and the protrusion ratio of the product can be reduced to below 4dB; the LDS process is used to make a three-dimensional conductive circuit on the base, which not only simplifies the traditional PFC structure and improves the aerodynamic noise, but also further reduces the axial thickness. At the same time, it is also very convenient to put all the components on the outside of the base, which facilitates the mounting of electronic components and improves the processability. In addition, if additional components need to be installed inside the base, such as LED lamps, if the PFC solution is used, interference problems must be considered, and a base with a three-dimensional conductive circuit can achieve three-dimensional electrical connection, and a circuit can also be formed in the recessed part, without interference problems, and has good scalability.

[0027] The present invention is further described below in conjunction with the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The three-dimensional structure of the present invention is shown in FIG. Figure 1 .

[0029] Figure 2 The three-dimensional structure of the present invention is shown in FIG. Figure 2 .

[0030] Figure 3 It is a cross-sectional structural schematic diagram of the present invention.

[0031] Figure 4 It is a schematic diagram of the decomposition structure of the present invention.

[0032] Figure 5 It is a structural schematic diagram of the base in the present invention.

[0033] Figure 6 This is the torque waveform diagram of comparative example 1.

[0034] Figure 7 This is the axial force waveform diagram of comparative example 1.

[0035] Figure 8 This is the radial unbalanced magnetic tension waveform diagram of comparative example 1.

[0036] Fig. 9 This is the torque waveform diagram of comparative example 2.

[0037] Fig.10 This is the axial force waveform diagram of comparative example 2.

[0038] Fig.11 This is the radial unbalanced magnetic pull waveform diagram of Example 2.

[0039] Fig.12 It is a torque waveform diagram of the three-phase six-slot eight-pole motor in the present invention.

[0040] Fig.13 It is the axial force waveform diagram of the three-phase six-slot eight-pole motor in the present invention.

[0041] Fig.14 It is a waveform diagram of radial unbalanced magnetic pull of the three-phase six-slot eight-pole motor in the present invention. DETAILED DESCRIPTION

[0042] For example, see Figures 1 to 5 The present embodiment provides an LDS micro heat dissipation module, which includes a top cover 1, a base 2, a back iron 3, an impeller 4, a motor housing 5, a magnet 6 and a stator winding 7.

[0043] A three-dimensional conductive circuit is formed on the surface of the base 2 by the LDS process, and the stator winding 7 is arranged on the base 2 and connected to the three-dimensional conductive circuit. The three-dimensional conductive circuit can be conveniently placed on the outside of the base 2, which facilitates the mounting of the electronic components 9 and improves the processability. In addition, when additional electronic components 9 need to be installed inside the base 2, such as LED lamps, if the PFC solution is adopted, the interference problem must be considered, and the base 2 with a three-dimensional conductive circuit can achieve three-dimensional electrical connection. Preferably, a tongue 10 is also provided on the outer wall of the base 2, and a gold finger is formed on the surface of the tongue 10 by the LDS process. The gold finger is connected to the three-dimensional conductive circuit, and the gold finger is convenient to adapt to the connector, and the assembly is simple and convenient. Moreover, compared with the traditional structure, the base 2 eliminates the via, has a good sealing effect, and can further improve the waterproof effect.

[0044] The base 2 is provided with a middle tube 21 at the center position corresponding to the stator winding 7. The base 2 and the middle tube 21 are integrally formed of LDS plastic, with a firm connection and good structural stability.

[0045] A bearing 22 is provided in the middle tube 21, and a rotating shaft matched with the bearing 22 is provided on the motor housing 5. The bearing 22 is installed in the rotating shaft to realize the rotation of the motor housing 5 set on the middle tube 21. The magnet 6 is set on the motor housing 5 corresponding to the position of the stator winding 7. The impeller 4 is sleeved on the motor housing 5, and the top cover 1 is covered on the base 2.

[0046] In this embodiment, the stator winding 7 is preferably a three-phase six-slot four-pole disc motor stator winding. In other embodiments, the stator winding 7 can also be a three-phase six-slot eight-pole or two-phase four-slot six-pole disc motor stator winding to reduce the unbalanced radial magnetic pull, improve the torque fluctuation and axial force fluctuation of the motor, and thus reduce the vibration noise of the product and improve the sound quality of the product. The coil in the stator winding 7 is preferably wound with self-adhesive enameled wire, and the coil can be used as a separate coil unit after forming, without the need to be coated with insulating material. In order to make full use of the space inside the motor, increase the slot full rate of the coil, increase the number of turns of the motor, and thus improve the efficiency of the motor.

[0047] The shape of the coil in the stator winding 7 is preferably a rounded trapezoid, which increases the magnetic flux of the coil turn chain, thereby improving the motor efficiency, and the motor efficiency can be increased to more than 30%.

[0048] Preferably, a concave cavity 23 for setting the stator winding 7 is provided on the inner bottom surface of the base 2. Specifically, an annular boss 24 is provided on the base 2 corresponding to the outer position of the periphery of the middle tube 21, and the concave cavity 23 is formed between the annular boss 24 and the middle tube 21. The stator winding 7 is arranged in the concave cavity 23. The outer side of the annular boss 24 is provided with a slope to transition with the inner bottom surface of the base 2, so that the air duct between the base 2 and the blades is more in line with the principles of fluid mechanics, and the aerodynamic noise can be reduced by more than 1.5dBA. In addition, a rounded trapezoidal boss 25 adapted to the coil can also be provided on the bottom surface of the concave cavity 23. The rounded trapezoidal boss 25 is located in the inner hole of the coil, and has a good matching effect with the coil, which improves the positioning accuracy of the coil and reduces the difficulty of assembling the coil.

[0049] The outer bottom surface of the base 2 is provided with an annular groove adapted to the back iron 3, and the back iron 3 is arranged in the annular groove, so that the distance between the back iron 3 and the three-dimensional conductive circuit is significantly increased, thereby effectively improving the antistatic level. In addition, the back iron 3 is moved to the outer bottom surface of the base 2, so that the joint between the base 2 and the middle tube 21 is moved upward, the structural rigidity of the middle tube 21 is improved, and the vibration is reduced. At the same time, it is easier to assemble the back iron 3. Since the fan size is very small, it is not as convenient to assemble the back iron 3 from the inside as from the outside.

[0050] A heat sink 8 is provided at the air duct position of the base 2, and the heat sink 8 includes a VC plate 81 and fins 82 arranged on the VC plate 81. The VC plate 81 is fixed to the base 2 by soldering, and has good stability. Ultrasonic or laser welding is preferably used between the top cover 1 and the base 2, and the connection is firm, the sealing effect is good, and the waterproof performance can be improved. Conventional micro heat sinks often use ordinary copper blocks as heat-absorbing bottoms. However, due to the limited thermal conductivity of the copper block, a temperature gradient will occur on the chip. On the one hand, this temperature gradient will cause the entire chip to enter overheat protection due to local high temperature, or not enter overheat protection because there is no temperature detection point in the local high temperature area, which will damage the chip. The thermal conductivity of the VC plate 81 can reach 100 times that of the copper block, and can be considered as a thermal superconductor, so the temperature gradient of the chip can be effectively improved.

[0051] Comparative Example 1: Compared with the motor with four slots and six poles and square wave drive in the micro radiator, the motor efficiency is 18.3% and the torque ripple is 42.9%. For the specific torque waveform, axial force waveform and unbalanced radial magnetic pull, see Figure 6 , Figure 7 and Figure 8 .

[0052] Comparative Example 2: Compared with the three-slot four-pole, sine wave driven motor in the micro radiator, the motor efficiency is 21.8% and the torque ripple is 1.9%. For the specific torque waveform, axial force waveform and unbalanced radial magnetic pull, see Fig. 9 , Fig.10 and Fig.11 .

[0053] The present invention is described by taking the stator winding 7 as a six-slot eight-pole, sine wave drive as an example. After testing, the motor efficiency is 34.5%, the torque ripple is 0.14%, and the specific torque waveform, axial force waveform and unbalanced radial magnetic pull are shown in Fig.12 , Fig.13 and Fig.14 .

[0054] It can be seen that the LDS micro heat dissipation module of the present invention effectively improves the torque fluctuation and axial force fluctuation of the motor compared with Comparative Examples 1 and 2, thereby reducing the vibration noise of the product and improving the sound quality of the product.

[0055] According to the disclosure and teaching of the above specification, technicians in the field to which the present invention belongs can also change and modify the above implementation. Therefore, the present invention is not limited to the specific implementations disclosed and described above, and some modifications and changes to the present invention should also fall within the scope of protection of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation to the present invention. As described in the above embodiments of the present invention, other modules and fan structures obtained by using the same or similar structures are all within the scope of protection of the present invention.

Claims

1. An LDS micro heat dissipation module, comprising a top cover, a base, a back iron, a motor housing, a magnet, a stator winding and an impeller, characterized in that: A three-dimensional conductive circuit is formed on the surface of the base by LDS process, the stator winding is arranged on the base and connected to the three-dimensional conductive circuit, the base is provided with a middle tube at the center position corresponding to the stator winding, the motor shell is rotatably arranged on the middle tube, the magnet is arranged on the motor shell at the position corresponding to the stator winding, the impeller is sleeved on the motor shell, the top cover is arranged on the base, and the stator winding is a three-phase six-slot four-pole, three-phase six-slot eight-pole or two-phase four-slot six-pole disc motor stator winding.

2. The LDS micro heat dissipation module according to claim 1, characterized in that: An inserting tongue is arranged on the outer side wall of the base, and a gold finger is formed on the surface of the inserting tongue by LDS process, and the gold finger is connected to the three-dimensional conductive circuit.

3. The LDS micro heat dissipation module according to claim 1, characterized in that: The coils in the stator winding are wound with self-adhesive enameled wires.

4. The LDS micro heat dissipation module according to claim 2, characterized in that: The coil in the stator winding is in the shape of a rounded trapezoid, and a rounded trapezoidal boss matched with the coil is provided on the inner bottom surface of the base.

5. The LDS micro heat dissipation module according to claim 1, characterized in that: A concave cavity for arranging the stator winding is provided on the inner bottom surface of the base.

6. The LDS micro heat dissipation module according to claim 5, characterized in that: An annular boss is provided on the base corresponding to the outer side of the periphery of the middle tube, a concave cavity is formed between the annular boss and the middle tube, the stator winding is arranged in the concave cavity, and a slope is provided on the outer side of the annular boss to transition to the inner bottom surface of the base.

7. The LDS micro heat dissipation module according to claim 1, characterized in that: The outer bottom surface of the base is provided with an annular groove matched with the back iron, and the back iron is arranged in the annular groove.

8. The LDS micro heat dissipation module according to claim 1, characterized in that: A radiator is arranged at the air duct position of the base, and the radiator comprises a VC plate and fins arranged on the VC plate, and the VC plate is fixed to the base by soldering.

9. The LDS micro heat dissipation module according to claim 1, characterized in that: The base and the middle tube are made of LDS plastic formed in one piece.

10. The LDS micro heat dissipation module according to any one of claims 1 to 9, characterized in that: The top cover and the base are welded by ultrasonic or laser.

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