Electric motor

Abstract

The present invention relates to an electric motor, which includes a rotating shaft extending axially, an inner rotor fixed to the rotating shaft, an outer stator sleeved on the outer periphery of the inner rotor, a fan fixed to the rotating shaft, and a wind guide cover located between the outer stator and the fan. The wind guide cover includes a first wind guide ring located at the rear end in the axial direction and a second wind guide ring located at the front end in the axial direction. The fan is located within the second wind guide ring. The first wind guide ring is disposed adjacent to the outer stator and the first wind guide ring has an inner diameter d3, and the outer stator has a first inner diameter d1. The inner diameter d3 of the first wind guide ring is greater than or equal to the first inner diameter d1 of the outer stator, significantly improving the heat dissipation effect.

Description

Technical Field

[0001] The present invention relates to an electric motor, and particularly to an electric motor with a wind guide cover.

Background Art

[0002] Although the wind guide plate used in traditional AC or DC power tool fans can, to a certain extent, guide the air flow into the fan inlet, it cannot reasonably distribute the heat dissipation flow of the motor to the air gap and the stator housing channel. This is extremely likely to cause uneven cooling of the outer stator, the coil, and the rotor, resulting in local overheating. For DC tools, it means frequent over-temperature protection of the machine.

[0003] In addition, regarding the structure of the wind guide cover itself, the prior art does not disclose its optimal structural dimensions for motor heat dissipation, fan power consumption, etc., nor does it disclose the relationship between the inner diameter of the wind guide cover, the distance from the coil, the rotor diameter, the inner and outer diameters of the outer stator, etc. and system heat dissipation.

[0004] In view of this, it is indeed necessary to provide an improved electric motor to overcome the defects existing in the prior art.

Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide an electric motor with improved heat dissipation performance.

[0006] The present invention can adopt the following technical solutions to solve the problems of the prior art: An electric motor includes a rotating shaft extending axially, an inner rotor fixed on the rotating shaft, an outer stator sleeved on the outer periphery of the inner rotor, and a fan arranged on the rotating shaft. The fan is located at the axial front end of the outer stator and rotates with the rotating shaft to generate an air flow to cool the outer stator. The electric motor further includes a wind guide cover located between the outer stator and the fan. The wind guide cover includes a first wind guide ring at the axial rear end and a second wind guide ring at the axial front end. The fan is located within the second wind guide ring. The first wind guide ring is adjacent to the outer stator and has a first wind guide ring inner diameter d3. The outer stator has a first inner diameter d1, and the inner diameter d3 of the first wind guide ring is greater than or equal to the first inner diameter d1 of the outer stator.

[0007] A further improvement is: The fan has a hub driven by the rotating shaft and several blades radially extending outward from the outer peripheral surface of the hub. The hub has a hub diameter d5, the inner rotor has a rotor outer diameter d0, and the hub diameter d5 is less than or equal to the rotor outer diameter d0.

[0008] A further improvement is: The second wind guide ring has an axial height h2, the blade has a blade height h3, and the axial height h2 of the second wind guide ring is greater than or equal to the blade height h3 of the blade 52.

[0009] A further improvement solution is as follows: The fan has a fan diameter d6, and the ratio of the hub diameter d5 to the fan diameter d6 is less than or equal to 0.5 and greater than or equal to 0.2.

[0010] A further improvement solution is as follows: The air guide cover has a guide vane located between the first air guide ring and the second air guide ring. The guide vane is provided with a first opening for the rotation shaft to pass through. The first opening has a guide vane inner diameter d4. Among them, the relationship between the guide vane inner diameter d4, the hub diameter d5, and the fan diameter d6 follows the following formula: 0.5(d5 + d6) ≤ d4 ≤ d6.

[0011] A further improvement solution is as follows: The first air guide ring has an axial height h1, and the ratio of the axial height h1 of the first air guide ring to the guide vane inner diameter d4 is less than or equal to 0.5 and greater than 0.1.

[0012] A further improvement solution is as follows: The second air guide ring has a second air guide ring inner diameter d7. Among them, the relationship between the second air guide ring inner diameter d7, the fan diameter d6, and the guide vane inner diameter d4 follows the following formula: d7 ≥ 2d6 – d4.

[0013] A further improvement solution is as follows: The air guide cover includes a rib protruding circumferentially outward along the inner side of the guide vane of the second air guide ring, and the rib is provided with a protrusion perpendicular to the second air guide ring.

[0014] A further improvement solution is as follows: The motor further includes an end plate located at the end side of the motor. The inner side of the first air guide ring is arc-shaped and the outer edge of the first air guide ring abuts against the end plate. The first air guide ring also has a first volute portion to conduct air flow.

[0015] A further improvement solution is as follows: The second air guide ring has a second volute portion for accommodating the fan and a second opening located circumferentially on the second air guide ring. The second opening is used to conduct air flow.

[0016] Compared with the prior art, the present invention has one or more of the following beneficial effects:

[0017] 1. By providing an air guide cover on the motor, the air guide cover includes a first air guide ring and a second air guide ring. The first air guide ring and the second air guide ring are hollow and open at both ends. The first air guide ring has an inner diameter d3, and the outer stator has a first inner diameter d1. It is set that the inner diameter d3 of the first air guide ring is greater than or equal to the inner diameter d1 of the outer stator. The air flow between the outer stator and the housing is not easy to enter between the first air guide ring and the housing, and the heat dissipation effect is good. The air flow passing through the fan can be increased by at least 10%.

[0018] 2. When the hub diameter d5 is less than or equal to the rotor outer diameter d0, the air flow between the outer stator and the rotor can completely enter the fan. Compared with the case where the hub diameter d5 is greater than the rotor outer diameter d0, the heat dissipation effect is better, and the motor heat dissipation flow rate can be increased by 5%.

[0019] 3. The axial height h2 of the second air guide ring is greater than or equal to the blade height h3 to ensure that the blades are completely located in the second volute part of the second air guide ring, which is beneficial to controlling the air flow direction and has a good heat dissipation effect.

[0020] 4. The fan has a fan diameter d6. When the ratio of the hub diameter d5 to the fan diameter d6 is less than or equal to 0.5 and greater than or equal to 0.2, it is not easy to form an eddy current area at the fan blades, the heat dissipation effect is good, and the motor heat dissipation flow rate can be increased by more than 5%.

[0021] 5. The inner diameter d4 of the air guide plate is greater than or equal to half of the sum of the hub diameter d5 and the fan diameter d6, and the inner diameter d4 of the air guide plate is less than or equal to the fan diameter d6. The heat dissipation effect is good, and the motor heat dissipation flow rate can be significantly increased by more than 10%.

[0022] 6. The first air guide ring has an axial height h1. When the ratio of the axial height h1 of the first air guide ring to the inner diameter d4 of the air guide plate is less than or equal to 0.5 and greater than 0.1, the heat dissipation effect is good. Compared with the case where the ratio is not within the range, the motor heat dissipation flow rate can be increased by more than 5%.

[0023] 7. The second air guide ring has an inner diameter d7. When the inner diameter d7 of the second air guide ring is greater than or equal to the difference between twice the fan diameter d6 and the inner diameter d4 of the air guide plate, the heat dissipation effect is good. Compared with the case where the inner diameter d7 of the second air guide ring is less than the difference between twice the fan diameter d6 and the inner diameter d4 of the air guide plate, the air flow out of the fan can obtain sufficient static pressure to overcome the flow resistance at this time, the motor heat dissipation flow rate increases by at least 10%, and the winding temperature rise decreases by more than 2°C.

[0024] 8. The inner side of the first air guide ring is arc-shaped. Compared with the case where the inner side is right-angled, it can avoid the air flow on the inlet side directly hitting the air guide plate of the air guide cover, resulting in the loss of air flow velocity, and can improve the heat dissipation effect.

Description of the Drawings

[0025] The following further describes in detail the specific embodiments of the present invention with reference to the drawings:

[0026] Figure 1 It is a cross-sectional view of the motor of the present invention applied to an electric tool;

[0027] Figure 2Is a three-dimensional schematic diagram of the motor according to the first embodiment of the present invention;

[0028] Figure 3 Is Figure 2 Exploded schematic diagram of the motor shown;

[0029] Figure 4 Is Figure 2 Cross-sectional view of the air guide cover in the motor shown;

[0030] Figure 5 Is a three-dimensional schematic diagram of the air guide cover in the motor according to the second embodiment of the present invention;

[0031] Figure 6 Is Figure 2 Cross-sectional view of the motor shown;

[0032] Figure 7 Is Figure 6 Schematic diagram of the first inner diameter d1 and the second inner diameter d2 of the outer stator in the motor shown;

[0033] Figure 8 Is Figure 6 Schematic diagram of d3 of the air guide cover in the motor shown;

[0034] Figure 9 Is Figure 6 Schematic diagram of the hub ratio of the fan shown.

[0035] Meanings of the reference numerals in the figure:

[0036] 100, motor 10, rotating shaft 20, inner rotor

[0037] 30, outer stator 31, stator core 32, winding

[0038] 40, air guide cover 41, first air guide ring 411, first volute part

[0039] 42, second air guide ring 421, second volute part 43, air guide plate

[0040] 431, first opening 44, second opening 45, extended edge

[0041] 451, protrusion 50, fan 51, hub

[0042] 52, blade 60, end plate 70, battery pack

[0043] 80, housing 90, circuit board d0, rotor outer diameter

[0044] d1, first inner diameter of the stator d2, second inner diameter of the stator d3, inner diameter of the first air guide ring

[0045] Inner diameter d4 of the air deflector, inner diameter d5, hub diameter d6, fan diameter

[0046] Inner diameter d7 of the second air guide ring, axial height h1 of the first air guide ring, axial height h2 of the second air guide ring

[0047] Blade height h3

Detailed implementation manners

[0048] The present invention will be further described in detail below with reference to the accompanying drawings and implementation manners.

[0049] The terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. For example, the terms indicating orientation or positional relationship such as "upper", "lower", "front", "rear", "left", "right" etc. are only based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device / component referred to must have a specific orientation or be constructed and operated in a specific orientation, and thus cannot be construed as a limitation to the present invention.

[0050] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "mounted", "connected" and "connected" 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 components. 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 situations.

[0051] In this article, all features defined in the form of a range or a percentage range, such as numerical values, quantities, ratios, are only for the sake of brevity and convenience. Accordingly, the description of a numerical range or a percentage range should be regarded as having covered and specifically disclosed all possible sub-ranges and individual numerical values within the range (including integers and fractions), especially integer numerical values. For example, the range description of "1 to 8" should be regarded as having specifically disclosed all sub-ranges such as 1 to 7, 2 to 8, 2 to 6, 3 to 6, 4 to 8, 3 to 8, etc., especially the sub-ranges defined by integer numerical values, and should be regarded as having specifically disclosed the individual numerical values such as 1, 2, 3, 4, 5, 6, 7, 8 within the range. Unless otherwise specified, the above interpretation method applies to all contents of the present invention throughout the text, regardless of the breadth of the range.

[0052] If a quantity or other numerical value or parameter is expressed as a range, a preferred range, or a series of upper and lower limits, it should be understood that all ranges formed by any pair of the upper limits or preferred values of the range and the lower limits or preferred values of the range have been specifically disclosed herein, whether or not these ranges are separately disclosed. In addition, when a numerical range is mentioned herein, unless otherwise specified, the range should include its endpoints and all integers and fractions within the range.

[0053] In this article, on the premise that the purpose of the invention can be achieved, a numerical value should be understood to have the accuracy of the significant digits of that numerical value. For example, the number 40.0 should be understood to cover the range from 39.50 to 40.49.

[0054] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0055] Please refer to Figure 1 As shown, an embodiment of the present invention relates to an electric motor 100, which is applied to power tools, including but not limited to a hammer drill, an angle grinder, or a jigsaw, to provide power for the power tool. In the present invention, the power tool is preferably a hammer drill, and the hammer drill is a portable direct-current hammer drill that can be installed with a battery pack 70. The battery pack 70 can be installed at the bottom of the handle through a battery pack installation guide rail. The circuit board 90 that controls the operation of the hammer drill is arranged at the bottom of the housing 80 and is electrically connected to the electric motor 100, the battery pack 70, the switch, etc. respectively. By using a wind guide cover arranged on the electric motor of the present invention, the ventilation conditions of the electric motor and the power tool can be improved, the temperature rise of the electric motor and the power tool can be effectively reduced, and the heat dissipation effect can be improved.

[0056] Please refer to Figure 2 and Figure 3 As shown, the electric motor 100 includes a rotating shaft 10 extending axially, an inner rotor 20 fixed to the outer periphery of the rotating shaft 10, an outer stator 30 sleeved outside the inner rotor 20, a wind guide cover 40 abutted against the electric motor, a fan 50 arranged on the rotating shaft 10, and an end plate 60 located at the end side of the electric motor. The inner rotor 20 is located between the rotating shaft 10 and the outer stator 30. The outer stator 30 includes a stator core 31 and a winding 32 sleeved outside the inner rotor 20. The fan 50 rotates with the rotating shaft 10 to generate an air flow. Installing a wind guide cover 40 between the electric motor 100 and the fan 50 can improve the heat dissipation performance of the electric motor 100. And the wind guide cover 40 includes a first wind guide ring 41 located at the rear end in the axial direction and a second wind guide ring 42 located at the front end in the axial direction. The first wind guide ring 41 and the second wind guide ring 42 respectively have a first volute portion 411 and a second volute portion 421. Arranging the fan 50 in the second volute portion 421 helps with heat dissipation.

[0057] Please refer to Figure 3 andFigure 4 As shown, the air guide cover 40 has an air guide plate 43 connected to the first air guide ring 41 and the second air guide ring 42. The air guide plate 43 is provided with a first opening 431 through which the rotating shaft passes. The first opening 431 has an inner diameter d4 of the air guide plate. The air guide cover 40 includes a circumferential extension 45 along the circumference of the air guide plate 43 inside the second air guide ring 42. The circumferential extension 45 is provided with a protrusion 451 perpendicular to the second air guide ring 42. The protrusion 451 is arranged in the housing 80 for positioning the air guide ring. The second air guide ring 42 has a second opening 44 to conduct the air flow. The motor further includes an end plate 60 located at the end side of the motor. The first air guide ring 41 has a first volute portion 411 to conduct the air flow. The outer edge of the first air guide ring 41 abuts against the end plate 60, and the inner side of the first air guide ring 41 is arc-shaped, which can prevent the air flow on the inlet side from directly hitting the air guide plate 43 of the air guide cover 40 and causing a loss of air flow velocity, and can improve the heat dissipation effect.

[0058] Please refer to Figure 5 As shown, which is another embodiment of the air guide cover of the present invention. It can be seen that the second air guide ring 42 is arc-shaped and may not have the second opening 44. Of course, preferably, the second air guide ring 42 has the second opening 44 to conduct the air flow, which has a better heat dissipation effect.

[0059] Please refer to Figure 6 、 Figure 7 and Figure 8 As shown, in an embodiment of the present invention, the first air guide ring 41 has an inner diameter d3, the outer stator 30 has a first inner diameter d1 of the stator, and the outer stator 30 has a second inner diameter d2 of the stator. The inner diameter d3 of the first air guide ring 41 is 40.1 mm, and the first inner diameter d1 of the stator of the outer stator 30 is 26.8 mm. In the embodiment of the present invention, the inner diameter d3 of the first air guide ring 41 is, for example but not limited to, 35 mm, 38 mm, 40 mm, 44.5 mm, 48 mm, 50 mm, and the first inner diameter d1 of the stator of the outer stator 30 is, for example but not limited to, 24 mm, 25.5 mm, 27 mm, 29 mm, 30 mm, 35 mm, 40 mm. The present invention finds through research that when the inner diameter d3 of the first air guide ring is greater than or equal to the inner diameter d1 of the outer stator, at this time, the air flow between the outer stator 30 and the housing 80 of the power tool is not easy to enter between the first air guide ring 41 and the housing 80 of the power tool, and the heat dissipation effect is good. Compared with the comparative example where the inner diameter d3 of the first air guide ring is 40.1 mm and the first inner diameter d1 of the stator of the outer stator 30 is 41 mm, the air flow passing through the fan can be increased by at least 10%.

[0060] The cooling fan is a very important component in the motor. The performance of the fan directly affects the heat dissipation capacity of the motor, thereby affecting the lifespan of the motor. Most of the blades of the cooling fan are free-form surfaces, and different structures will also be designed for other parts according to the actual working conditions. There are two types of motor cooling fans: thrust type and centrifugal type. The spiral fan belongs to the thrust type, and the straight fan blades are centrifugal type. The wind of the thrust fan blows longitudinally, acts on the motor end cover and rebounds, resulting in poor heat dissipation effect on the motor housing. The wind of the centrifugal fan radiates in all directions, acts on the arc-shaped tail cover of the motor and flows to the heat dissipation ribs of the motor housing, which has a better heat dissipation effect on the motor housing, but will increase the volume of the motor and also increase the cost. In the invention, preferably, the selected fan 50 is a centrifugal fan 50.

[0061] Please refer to Figure 9 As shown, the fan 50 has a hub 51 driven by the rotating shaft 10 and several blades 52 radially protruding outward from the outer peripheral surface of the hub 51. The hub 51 has a hub diameter d5, and the fan 50 has a fan diameter d6. The fan diameter d6 is approximately the same as the size of the second inner diameter d2 of the stator. In the present invention, the ratio of the hub diameter d5 to the fan diameter d6 is defined as the hub ratio. While the fan 50 rotates to generate the air flow required for motor heat dissipation, it also becomes a motor load, which has a greater impact on the motor efficiency. The researchers of the present invention found through a large number of experiments and studies that when the hub ratio is less than or equal to 0.5 and greater than or equal to 0.2, the heat dissipation problem can be improved. In the embodiment of the present invention, the hub diameter d5 is 22 mm and the fan diameter d6 is 44 mm. Of course, in the embodiment of the present invention, the hub diameter d5 is not limited to 22 mm. The hub diameter d5 is, for example but not limited to, 20 mm, 21 mm, 23 mm, 25 mm, 28 mm, 30 mm, and the fan diameter d6 is, for example but not limited to, 30 mm, 45 mm, 48 mm, 50 mm, 54 mm, 56 mm, 60 mm.

[0062] When the hub ratio is too small, such as when the hub ratio of the comparative example is 0.1, the air intake at the blade root is insufficient to cool the bottom of the winding coil, resulting in a temperature increase of more than 5% in the winding coil and damaging the motor. When the hub ratio is less than or equal to 0.5, such as when the hub ratio of the embodiment is 0.3, compared with a fan with a hub ratio greater than 0.5, such as when the hub ratio of the comparative example is 0.7, the embodiment can ensure that the air intake at the blade root cools the bottom of the winding, reducing the winding temperature by more than 3%.

[0063] Please refer to Figure 6As shown, the inner rotor has a rotor outer diameter d0. In an embodiment of the present invention, the rotor outer diameter d0 is, for example but not limited to, 20 mm, 21 mm, 22 mm, 23 mm, 25 mm, 28 mm, 30 mm. In order to improve the heat dissipation effect, through a large number of creative experiments, it is obtained that when the hub diameter d5 is less than or equal to the rotor outer diameter d0, for example, in one embodiment, the hub diameter d5 is 23 mm and the rotor outer diameter d0 is 26 mm, the air flow between the outer stator 30 and the inner rotor 20 can completely enter the fan 50. Compared with the case where the hub diameter d5 is greater than the rotor outer diameter d0, for example, in the comparative example, the hub diameter d5 is 40 mm and the rotor outer diameter d0 is 35 mm, the heat dissipation effect of the embodiment of the present invention is good, and the motor heat dissipation flow rate can be increased by 5%.

[0064] Furthermore, the second air guide ring 42 has an axial height h2, and the blade 52 has a blade height h3. In an embodiment of the present invention, the axial height h2 of the second air guide ring 42 is 5 mm, and the blade height h3 of the blade 52 is 3.9 mm. In a preferred embodiment of the present invention, the axial height h2 of the second air guide ring 42 is, for example but not limited to, 4 mm, 4.5 mm, 5.2 mm, 6 mm, 8 mm, 10 mm, and the blade height h3 of the blade 52 is, for example but not limited to, 2 mm, 2.5 mm, 3 mm, 3.4 mm, 4 mm, 5 mm, 6 mm. The present invention finds through research that the axial height h2 of the second air guide ring 42 is greater than or equal to the blade height h3. For example, compared with the comparative example where the axial height h2 of the second air guide ring 42 is 3 mm and the blade height h3 of the blade 52 is 3.9 mm, at this time, it can be ensured that the blade 52 is completely located in the second volute portion 421 of the second air guide ring 42, which is beneficial to controlling the air flow direction and has a good heat dissipation effect.

[0065] Please refer to Figure 3 、 Figure 6As shown, the air guide cover 40 has an air guide plate 43 connected to the first air guide ring 41 and the second air guide ring 42. The air guide plate 43 has an inner diameter d4 of the air guide plate. The inner diameter d4 of the air guide plate is, for example but not limited to, 30mm, 33mm, 35.5mm, 36.5mm, 37.2mm, 39.6mm, 40.8mm, 45mm. In a preferred embodiment of the present invention, the inner diameter d4 of the air guide plate is 35.5mm. After a large amount of creative work, the inventor unexpectedly found that when the inner diameter d4 of the air guide plate is greater than the fan diameter d6, for example, the inner diameter d4 of the air guide plate is 40mm and the fan diameter d6 is 35mm in the comparative example, crosswind will occur, and the air guide cover will not play a role in guiding air; if the inner diameter d4 of the air guide plate is too small, for example, the inner diameter d4 of the air guide plate is less than half of the sum of the hub diameter d5 and the fan diameter d6, for example, the inner diameter d4 of the air guide plate is 20mm, the hub diameter d5 is 28mm, and the fan diameter d6 is 50mm in the comparative example, at this time, the air flow resistance will be too large, resulting in a reduction of more than 5% in the heat dissipation flow of the entire power tool. Only when the inner diameter d4 of the air guide plate is greater than or equal to half of the sum of the hub diameter d5 and the fan diameter d6, and the inner diameter d4 of the air guide plate is less than or equal to the fan diameter d6, for example, the inner diameter d4 of the air guide plate is 35.5mm, the hub diameter d5 is 22mm, and the fan diameter d6 is 44mm, the heat dissipation effect is better at this time, and the heat dissipation flow of the motor is greatly improved, reaching more than 10%.

[0066] Please refer to Figure 6 As shown, the first air guide ring has an axial height h1. The axial height h1 of the first air guide ring is, for example but not limited to, 5mm, 8.2mm, 10mm, 11.5mm, 12.5mm, 15mm. In a preferred embodiment of the present invention, the axial height h1 of the first air guide ring is 8.2mm. The inventor found that when the ratio of the axial height h1 of the first air guide ring to the inner diameter d4 of the air guide plate is less than or equal to 0.5, the heat dissipation effect is better. If the ratio of the axial height h1 of the first air guide ring to the inner diameter d4 of the air guide plate is too small, for example, the axial height h1 is 5mm and the inner diameter d4 of the air guide plate is 50mm, the hot air flowing out between the winding coils is likely to directly impact the wall of the air guide cover, increasing the flow resistance and causing a local temperature rise of more than 3%; if the ratio of the axial height h1 of the first air guide ring to the inner diameter d4 of the air guide plate is too large, for example, the axial height h1 is 18mm and the inner diameter d4 of the air guide plate is 30mm, then the axial flow space inside the first air guide ring is too large, easily forming an annular eddy current area, which is not conducive to the direct inflow of hot air into the fan for discharge, and the heat dissipation flow of the motor is reduced by more than 5%.

[0067] In one embodiment, the second air guide ring has an inner diameter d7. The inner diameter d7 of the second air guide ring is, for example but not limited to, 50 mm, 54.2 mm, 58 mm, 60 mm, 62 mm, 65 mm, 70 mm. In a preferred embodiment of the present invention, the inner diameter d7 of the second air guide ring is 60.1 mm. After a large amount of creative work, the inventor found that when the inner diameter d7 of the second air guide ring is greater than or equal to the difference between twice the fan diameter d6 and the inner diameter d4 of the air guide plate, that is, the relationship between the inner diameter d7 of the second air guide ring, the fan diameter d6 and the inner diameter d4 of the air guide plate follows the following formula: d7≥2d6–d4. For example, when the inner diameter d7 of the second air guide ring is 60.1 mm, the fan diameter d6 is 44 mm, and the inner diameter d4 of the air guide plate is 35.5 mm, the total pressure efficiency increases significantly. When the inner diameter d7 of the second air guide ring is less than the difference between twice the fan diameter d6 and the inner diameter d4 of the air guide plate, for comparison, for example, when the inner diameter d7 of the second air guide ring is 40 mm, the fan diameter d6 is 44 mm, and the inner diameter d4 of the air guide plate is 35.5 mm, at this time, the air outlet of the fan 50 cannot obtain sufficient diffuser pressure. Further, at this time, the flow rate is too low, the static pressure is not high, so the air outlet resistance is too large and the air outlet is not smooth. Compared with the comparative example of the latter, in the embodiment of the former, since the air flow of the fan air outlet can obtain sufficient static pressure to overcome the flow resistance, the heat dissipation flow rate of the motor increases by at least 10%, and the winding temperature rise is reduced by more than 2 °C.

[0068] By restricting the parameters, when the motor starts to work, the blade 52 located in the second volute part 421 will be driven to rotate at a high speed. Due to the setting of the air guide cover 40, therefore, the heat dissipation effect of the motor 100 is enhanced, and at the same time, the noise generated by the rotation of the motor 100 can also be reduced.

[0069] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0070] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and purposes of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A motor, comprising a rotating shaft extending axially, an inner rotor fixed to the rotating shaft, an outer stator sleeved on the outer periphery of the inner rotor, and a fan arranged on the rotating shaft, the fan being located at the axial front end of the outer stator and rotating with the rotating shaft to generate an air flow to cool the outer stator; Characterized in that: The motor further includes a wind guide cover located between the outer stator and the fan, the wind guide cover includes a first wind guide ring located at the axial rear end of the wind guide cover and a second wind guide ring located at the axial front end of the wind guide cover, the fan is located within the second wind guide ring, the first wind guide ring is arranged adjacent to the outer stator and has a first inner diameter d3 of the first wind guide ring, the outer stator has a first inner diameter d1, and the inner diameter d3 of the first wind guide ring is greater than or equal to the first inner diameter d1 of the outer stator; the fan has a hub driven by the rotating shaft and several blades radially extending outward from the outer peripheral surface of the hub, the hub has a hub diameter d5, the fan has a fan diameter d6, the wind guide cover has a wind guide plate located between the first wind guide ring and the second wind guide ring, the wind guide plate is provided with a first opening for the rotating shaft to pass through, the first opening has a wind guide plate inner diameter d4, wherein, the relationship among the wind guide plate inner diameter d4, the hub diameter d5, and the fan diameter d6 follows the following formula: 0.5(d5 + d6) ≤ d4 ≤ d6.

2. The motor according to claim 1, Characterized in that: The inner rotor has a rotor outer diameter d0, and the hub diameter d5 is less than or equal to the rotor outer diameter d0.

3. The motor according to claim 2, Characterized in that: The second wind guide ring has an axial height h2, the blade has a blade height h3, and the axial height h2 of the second wind guide ring is greater than or equal to the blade height h3 of the blade.

4. The motor according to claim 3, Characterized in that: The ratio of the hub diameter d5 to the fan diameter d6 is less than or equal to 0.5, and the ratio of the hub diameter d5 to the fan diameter d6 is greater than or equal to 0.

2.

5. The motor according to claim 4, Characterized in that: The first wind guide ring has an axial height h1, and the ratio of the axial height h1 of the first wind guide ring to the wind guide plate inner diameter d4 is less than or equal to 0.5 and greater than or equal to 0.

1.

6. The motor according to claim 4, Characterized in that: The second wind guide ring has a second inner diameter d7 of the second wind guide ring, wherein, the relationship among the second inner diameter d7 of the second wind guide ring, the fan diameter d6, and the wind guide plate inner diameter d4 follows the following formula: d7 ≥ 2d6 - d7.

7. The motor according to claim 4, Characterized in that: The wind guide cover includes a border protruding circumferentially outward along the wind guide plate inside the second wind guide ring, and the border is provided with a protrusion perpendicular to the second wind guide ring.

8. The motor according to claim 1, Characterized in that: The motor further includes an end plate located at the end side of the motor. The inner side of the first air guiding ring is arc-shaped and the outer edge of the first air guiding ring abuts against the end plate. The first air guiding ring further has a first volute portion to conduct air flow.

9. The motor according to claim 8, wherein: the second air guiding ring has a second volute portion for accommodating the fan and a second opening located in the circumferential direction of the second air guiding ring, and the second opening is used to conduct air flow.

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