Outrunner motor

Abstract

Provided is an outrunner motor, comprising a rotating shaft (1), a stator assembly (2), an outer rotor assembly (3), and a bearing seat (4). The stator assembly (2) is nestedly mounted outside a sleeve (42), the outer rotor assembly (3) is sleeved outside the stator assembly (2), and the outer rotor assembly (3) comprises a housing (31) and a plurality of permanent magnets (32). The stator assembly (2) is located in the housing (31), and an upper end fan (33) and a lower end fan (34) are mounted therein on an upper side and a lower side of the permanent magnets (32), respectively. The upper end fan (33) comprises an upper wind shield (331) and a plurality of upper flow guide blades (332) protruding from the upper wind shield (331). The lower end fan (34) comprises a lower wind shield (341) and a plurality of lower flow guide blades (342) protruding from the lower wind shield (341), and the lower wind shield (341) is further provided with a plurality of ventilation holes (344). The upper flow guide blades (332) and the lower flow guide blades (342) all face the stator assembly (2) and are distributed in a staggered manner in the circumferential direction, and the upper end fan (33) and the lower end fan (34) rotate together with the outer rotor assembly (3), so that air circulation at the upper end and the lower end is formed in the interior of the motor, and the risk of failure caused by uneven increases in the temperature of a stator winding is effectively solved. No ventilation holes are formed in the exterior of the motor, and the protection performance of the motor is high.

Description

An outer rotor motor Technical Field

[0001] The invention relates to an outer rotor motor. Background Art

[0002] On November 17, 2021, the applicant applied for a utility model patent entitled: An outer rotor motor with a new heat dissipation structure, with the patent publication number: 202122810211.X. In this patent, several ventilation holes are opened at the top of the casing of the outer rotor assembly. This patent can solve the ventilation and heat dissipation problems, but the protection level is reduced.

[0003] To maintain the required protection level and high power density, external rotor motors with high protection levels require that the outer rotor assembly's casing be protected from ventilation holes and that the outer rotor assembly and bearing housing be tightly fitted. This encloses the entire stator assembly, preventing heat dissipation through convection. Heat generated by the stator windings and core losses during operation must be conducted to the exterior of the motor through the bearing housing, which supports the stator assembly. However, the bearing housing has a limited conduction area and insufficient heat transfer capacity. As losses gradually increase, heat from the stator windings and core cannot be effectively dissipated, resulting in a top-down temperature gradient within the stator assembly. The stator windings farther from the bottom of the bearing housing are significantly hotter than those closer to the bearing housing, and the stator coil windings are significantly hotter than those at the bottom of the bearing housing. (For example, in a 15HP high-power motor, the temperature rise of the coil windings at the top of the bearing housing is 25K higher than that at the bottom of the bearing housing, and 50K higher than that at the bottom of the bearing housing.)

[0004] Figure 1 shows a schematic diagram of heat transfer. The arrows in the diagram indicate the contact heat transfer path, which is: coil winding - bearing seat (from top to bottom) - bearing seat bottom (from inside to outside) - external air. Heat is ultimately conducted between the cooling ribs at the bearing seat bottom and the cool air outside. This results in better heat dissipation for the coil winding closer to the bearing seat bottom, and worse heat dissipation for the coil winding farther from the bearing seat bottom. This ultimately leads to a significant difference in temperature rise at both ends of the coil winding within the same wire slot.

[0005] Summary of the Invention

[0006] The present invention provides an outer rotor motor to solve the technical problems in the prior art of outer rotor motors with high protection level requirements, such as the inability to form air circulation inside the motor due to the top of the rotor casing being sealed (no ventilation holes being opened), slow heat dissipation, and a large difference in temperature rise between the two ends of the coil winding in the same wire embedding slot in the stator assembly.

[0007] The technical solution of the present invention is achieved as follows:

[0008] The present invention discloses an outer rotor motor, comprising a rotating shaft, a stator assembly, an outer rotor assembly and a bearing seat, wherein the bearing seat comprises a bottom plate and a sleeve protruding upward from the middle of the bottom plate, a bearing is installed inside the sleeve, the rotating shaft support is installed on the bearing, the stator assembly is nested and installed on the outside of the sleeve, the outer rotor assembly is sleeved on the outside of the stator assembly, the outer rotor assembly comprises a casing, the casing comprises a top plate and a cylindrical side plate connected together, a plurality of permanent magnets are installed on the inner wall surface of the cylindrical side plate, the top plate and the cylindrical side plate form a cavity, the stator assembly is located in the cavity, one end of the rotating shaft is connected to the top plate and installed together, and is characterized in that: an upper end fan and a lower end fan are respectively installed on the upper and lower sides of the permanent magnet, wherein,

[0009] The upper end fan includes an upper wind shield and a plurality of upper guide blades protruding from the upper wind shield, an upper center hole is provided in the middle of the upper wind shield, and the plurality of upper guide blades are circumferentially distributed around the outer portion of the upper center hole;

[0010] The lower end fan includes a lower wind shield and a plurality of lower guide blades protruding from the lower wind shield. A lower center hole is provided in the middle of the lower wind shield. A plurality of ventilation holes are also provided on the lower wind shield. The plurality of ventilation holes and the plurality of lower guide blades are circumferentially distributed around the periphery of the lower center hole.

[0011] The upper guide blades and the lower guide blades are all oriented toward the stator assembly and staggered in the circumferential direction so that the upper end fan and the lower end fan rotate together with the outer rotor assembly, forming an upper and lower end air circulation inside the motor to accelerate heat dissipation.

[0012] As mentioned above, an upper convex ring protrudes axially on the edge of the upper wind shield, and a plurality of circumferentially spaced upper inserts protrude axially on the surface of the upper convex ring; a lower convex ring protrudes axially on the edge of the lower wind shield, and a plurality of circumferentially spaced lower inserts protrudes axially on the surface of the lower convex ring; two adjacent permanent magnets are separated by the upper insert and the lower insert, and the upper end fan and the lower end fan are located in the cavity.

[0013] The above-mentioned several upper guide blades are circumferentially distributed around the outer 180-degree circumference of the upper center hole, and the remaining 180-degree circumference of the center hole is empty; the several lower guide blades are circumferentially distributed around the outer 180-degree circumference of the lower center hole, and several ventilation holes are distributed around the remaining 180-degree circumference of the lower center hole.

[0014] A mounting seat is protruded from the center of the top plate toward the cavity, and one end of the rotating shaft extends from the sleeve and is mounted and connected to the mounting seat.

[0015] The number of the ventilation holes is at least two.

[0016] The bending directions of the upper guide vane and the lower guide vane are opposite to each other.

[0017] The bottom plate is protruded with a plurality of heat dissipation ribs.

[0018] The above-mentioned heat dissipation ribs include internal heat dissipation ribs and external heat dissipation ribs. The internal heat dissipation ribs are located below the casing, and the external heat dissipation ribs are located outside the internal heat dissipation ribs. The internal heat dissipation ribs are arranged in multiple concentric circles with the sleeve as the center.

[0019] The aforementioned plurality of external heat dissipation ribs are radially arranged with the sleeve as the center.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. The outer rotor motor comprises a rotating shaft, a stator assembly, an outer rotor assembly and a bearing seat, the bearing seat comprises a bottom plate and a sleeve protruding upward from the middle of the bottom plate, a bearing is installed inside the sleeve, the rotating shaft support is installed on the bearing, the stator assembly is nested and installed on the outside of the sleeve, the outer rotor assembly is sleeved on the outside of the stator assembly, the outer rotor assembly comprises a casing, the casing comprises a top plate and a cylindrical side plate connected together, a plurality of permanent magnets are installed on the inner wall surface of the cylindrical side plate, the top plate and the cylindrical side plate form a cavity, the stator assembly is located in the cavity, one end of the rotating shaft is connected and installed together with the top plate, characterized in that: an upper end fan and a lower end fan are respectively installed on the upper and lower sides of the permanent magnet, wherein the upper end fan comprises an upper wind shield and a plurality of upper guide blades protruding from the upper wind shield, an upper center hole is provided in the middle of the upper wind shield, and the plurality of upper guide blades are circumferentially distributed around the outer portion of the upper center hole; the lower end fan The motor is constructed by rotating the fan blades along the length of the motor shaft, rotating the fan blades along the length of the motor shaft, and rotating the fan blades along the length of the motor shaft to rotate relative to the stator assembly. The motor is constructed by rotating the fan blades along the length of the motor shaft, rotating the fan blades along the length of the motor shaft to rotate relative to the stator assembly. The motor is constructed by rotating the fan blades along the length of the motor shaft, rotating the fan blades along the length of the motor shaft to rotate relative to the stator assembly.

[0022] 2. Other advantages of the present invention are described in detail in the embodiment section. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG1 is a schematic diagram of heat transfer inside an outer rotor motor in the prior art;

[0024] FIG2 is a schematic structural diagram of an outer rotor motor provided in an embodiment of the present invention;

[0025] FIG3 is a side view of an outer rotor motor;

[0026] FIG4 is a cross-sectional view taken along line AA of FIG3 ;

[0027] FIG5 is a BB cross-sectional view of FIG3 ;

[0028] Figure 6 is an enlarged view of point C in Figure 5;

[0029] FIG7 is an exploded view of an outer rotor assembly of an outer rotor motor;

[0030] FIG8 is an exploded view of the outer rotor assembly from another angle;

[0031] FIG9 is a schematic structural diagram of the fan at the upper end of the outer rotor motor;

[0032] FIG10 is a schematic structural diagram of the fan at the lower end of the outer rotor motor;

[0033] FIG11 is a schematic structural diagram of a bearing seat of an outer rotor motor;

[0034] FIG12 is a schematic diagram of heat conduction inside an outer rotor motor. DETAILED DESCRIPTION

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0036] As shown in Figures 2 to 11, this embodiment provides an outer rotor motor, including a rotating shaft 1, a stator assembly 2, an outer rotor assembly 3 and a bearing seat 4. The bearing seat 4 includes a bottom plate 41 and a sleeve 42 protruding upward from the middle of the bottom plate 41. A bearing 43 is installed inside the sleeve 42. The rotating shaft 1 is supported and installed on the bearing 43. The stator assembly 2 is nested and installed on the outside of the sleeve 42. The outer rotor assembly 3 is sleeved on the outside of the stator assembly 2. The outer rotor assembly 3 includes a casing 31. The casing 31 includes a top plate 311 and a cylindrical side plate 312 connected together. A plurality of permanent magnets 32 are installed on the inner wall surface of the cylindrical side plate 312. The top plate 311 and the cylindrical side plate 312 form a cavity 310. The stator assembly 2 is located in the cavity 310. One end of the rotating shaft 1 is connected and installed together with the top plate 311. It is characterized in that an upper end fan 33 and a lower end fan 34 are respectively installed on the upper and lower sides of the permanent magnet 32, wherein,

[0037] The upper end fan 33 includes an upper wind shield 331 and a plurality of upper guide blades 332 protruding from the upper wind shield 331. An upper center hole 333 is provided in the middle of the upper wind shield 331, and the plurality of upper guide blades 332 are circumferentially distributed around the outer portion of the upper center hole 333. The lower end fan 34 includes a lower wind shield 341 and a plurality of lower guide blades 342 protruding from the lower wind shield 341. A lower center hole 343 is provided in the middle of the lower wind shield 341, and a plurality of ventilation holes 344 are also provided on the lower wind shield 341. The plurality of ventilation holes 344 and the plurality of lower guide blades 342 are circumferentially distributed around the outer portion of the lower center hole 343.

[0038] The upper guide blades 332 and the lower guide blades 342 are all oriented toward the stator assembly 2 and staggered in the circumferential direction, so that the upper end fan 33 and the lower end fan 34 rotate together with the outer rotor assembly 3, forming an upper and lower end air circulation inside the motor to accelerate heat dissipation.

[0039] The stator assembly 2 includes a stator core 21 and coil windings 22 , with a winding slot gap 23 formed between two adjacent coil windings 22 .

[0040] The outer rotor motor described in this embodiment adds a new heat circulation loop in the cavity 310, and the heat of the stator assembly 2 is extracted through the winding slot gap 23 of the stator assembly 2 by the upper end fan 33 and the lower end fan 34, thereby improving the heat transfer effect and effectively solving the potential failure risk caused by uneven temperature rise of the stator winding; and no ventilation holes are opened on the outside of the motor, thereby ensuring the protective performance of the motor; the upper end fan 33 and the lower end fan 34 have a simple structure and low cost.

[0041] As mentioned above, an upper raised ring 335 protrudes axially from the edge of the upper windshield 331, and a plurality of circumferentially spaced upper inserts 336 protrude axially from the surface of the upper raised ring 335. A lower raised ring 345 protrudes axially from the edge of the lower windshield 341, and a plurality of circumferentially spaced lower inserts 336 protrude axially from the surface of the lower raised ring 345. Adjacent permanent magnets 32 are separated by the upper and lower inserts 336, and the upper and lower fans 33, 34 are located within the cavity 310. The upper and lower inserts 336 facilitate and reliably install the upper and lower fans 33, 34.

[0042] The aforementioned upper guide blades 332 are circumferentially distributed around a 180-degree circumference of the outer periphery of the upper center hole 333, and the remaining 180-degree circumference of the outer periphery of the center hole 333 is empty; the aforementioned lower guide blades 342 are circumferentially distributed around a 180-degree circumference of the outer periphery of the lower center hole 343, and the aforementioned ventilation holes 344 are distributed around the remaining 180-degree circumference of the outer periphery of the lower center hole 343.

[0043] A mounting seat 313 protrudes from the center of the top plate 311 toward the cavity 310 , and one end of the rotating shaft 1 extends from the sleeve 42 and is mounted and connected to the mounting seat 313 .

[0044] The number of the ventilation holes 344 is at least two, so that the air in the outer rotor assembly 3 can circulate more smoothly.

[0045] The upper guide vanes 332 and the lower guide vanes 342 are bent in opposite directions, which is more conducive to heat conduction.

[0046] Specifically, the upper guide vane 332 is curved counterclockwise, and the lower guide vane 342 is curved clockwise.

[0047] The bottom plate 41 is provided with a plurality of heat dissipation ribs.

[0048] The heat dissipation ribs described above include internal heat dissipation ribs 411 and external heat dissipation ribs 412. The internal heat dissipation ribs 411 are located below the casing 31, and the external heat dissipation ribs 412 are located outside the internal heat dissipation ribs 411. The internal heat dissipation ribs 411 are arranged in a plurality of concentric circles with the sleeve 42 as the center. Since the ventilation holes 344 of the lower end fan 34 rotate to form a circular heat dissipation airflow, the circular heat dissipation ribs can better increase the contact area between the airflow and the internal heat dissipation ribs 411, thereby improving the heat dissipation efficiency. A number of heat dissipation ribs are provided at the bottom of the bearing seat 4. The hot air blown out by the upper end fan 33 and the lower end fan 34 is transferred to a number of heat dissipation ribs provided at the bottom of the bearing seat 4. The heat is transferred to the heat dissipation ribs outside the motor and then conducted to the outside of the motor.

[0049] Since the position of the ventilation holes 344 on the lower end fan 34 rotates with the outer rotor, a circumferentially varying heat dissipation airflow is formed. Therefore, circumferentially distributed internal heat dissipation ribs 411 are provided inside the motor to increase the contact area between the airflow and the internal heat dissipation ribs 411, thereby improving the heat dissipation efficiency. The external heat dissipation ribs 412 are used to conduct heat from the inside to the outside. Therefore, the external heat dissipation ribs 412 on the outside of the motor are evenly distributed in the vertical and circumferential directions to conduct heat to the outside as much as possible.

[0050] The plurality of external heat dissipation ribs 412 are radially arranged with the sleeve 42 as the center. The radial external heat dissipation ribs 412 can better conduct heat from the internal heat dissipation ribs 411 to the outside, further enhancing the heat dissipation effect.

[0051] As shown in Figure 12, the outer rotor motor described in this embodiment has two internal air flow routes. ① is the heat transfer route in the prior art (indicated by hollow wire ends in the figure, which is a contact heat transfer path): the heat of the stator assembly 2 is transferred to the bottom plate 41 through the sleeve 42 and then sent to the outside of the motor; ② is the newly added heat transfer route in this embodiment (indicated by solid wire ends in the figure, through which air is transferred): the upper guide vanes 332 draw the internal hot air heat of the stator assembly 2 upward from the winding slot gap and guide it to the bladeless area within the upper guide vanes 332; and below the stator assembly 2, the lower guide vanes 342 draw the internal heat of the stator assembly 2 and the heat below the upper wind shield 331 through the winding slot gap, and then guide it to the bladeless area within the lower end fan 34. The heat contacts the heat dissipation ribs at the bottom of the bearing seat through the ventilation holes 344 and is then conducted out of the motor.

[0052] The outer rotor motor described in this embodiment has a simple structure, good heat dissipation effect and stable performance.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. An outer rotor motor, comprising a rotating shaft (1), a stator assembly (2), an outer rotor assembly (3) and a bearing seat (4), wherein the bearing seat (4) comprises a bottom plate (41) and a sleeve (42) protruding upward from the middle of the bottom plate (41), a bearing (43) is installed inside the sleeve (42), the rotating shaft (1) is supported and installed on the bearing (43), the stator assembly (2) is nested and installed outside the sleeve (42), the outer rotor assembly (3) is sleeved outside the stator assembly (2), the outer rotor assembly (3) comprises a housing (31), the housing (31) comprises a top plate (311) and a cylindrical side plate (312) connected together, the cylindrical side plate A plurality of permanent magnets (32) are mounted on the inner wall surface of the housing (312), the top plate (311) and the cylindrical side plate (312) form a cavity (310), the stator assembly (2) is located in the cavity (310), one end of the rotating shaft (1) is connected and mounted with the top plate (311), and the characteristics are: An upper end fan (33) and a lower end fan (34) are respectively installed on the upper and lower sides of the permanent magnet (32), wherein: The upper end fan (33) comprises an upper wind shield (331) and a plurality of upper guide blades (332) protruding from the upper wind shield (331); an upper center hole (333) is provided in the middle of the upper wind shield (331); and the plurality of upper guide blades (332) are circumferentially distributed around the outer portion of the upper center hole (333); The lower end fan (34) comprises a lower wind shield (341) and a plurality of lower guide blades (342) protruding from the lower wind shield (341); a lower center hole (343) is arranged in the middle of the lower wind shield (341); a plurality of ventilation holes (344) are also arranged on the lower wind shield (341); the plurality of ventilation holes (344) and the plurality of lower guide blades (342) are circumferentially distributed around the periphery of the lower center hole (343); The plurality of upper guide blades (332) and the plurality of lower guide blades (342) are all oriented toward the stator assembly (2) and are staggered in the circumferential direction so that the upper end fan (33) and the lower end fan (34) rotate together with the outer rotor assembly (3), thereby forming an upper and lower end air circulation inside the motor and accelerating heat dissipation.

2. An outer rotor motor according to claim 1, characterized in that: An upper convex ring (335) is axially protruded from the edge of the upper wind shield (331), and a plurality of upper inserts (336) are axially protruded from the surface of the upper convex ring (335) at circumferential intervals; A lower convex ring (345) is axially protruded from the edge of the lower wind shield plate (341), and a plurality of circumferentially spaced lower inserts (346) are axially protruded from the surface of the lower convex ring (345); Two adjacent permanent magnets (32) are separated by an upper insert (336) and a lower insert (346), and an upper end fan (33) and a lower end fan (34) are located in the cavity (310).

3. An outer rotor motor according to claim 1 or 2, characterized in that: A plurality of upper guide blades (332) are circumferentially distributed around a 180-degree circumference of the outer periphery of the upper center hole (333), and the remaining 180-degree circumference of the outer periphery of the center hole (333) is empty; a plurality of lower guide blades (342) are circumferentially distributed around a 180-degree circumference of the outer periphery of the lower center hole (343), and a plurality of ventilation holes (344) are distributed around the remaining 180-degree circumference of the outer periphery of the lower center hole (343).

4. An outer rotor motor according to claim 3, characterized in that: A mounting seat (313) protrudes from the center of the top plate (311) toward the cavity (310), and one end of the rotating shaft (1) extends from the sleeve (42) and is mounted and connected to the mounting seat (313).

5. An outer rotor motor according to claim 4, characterized in that: The number of the ventilation holes (344) is at least two.

6. The outer rotor motor according to claim 4, characterized in that: The upper guide vane (332) and the lower guide vane (342) have opposite bending directions.

7. An outer rotor motor according to claim 6, characterized in that: The bottom plate (41) is provided with a plurality of heat dissipation ribs protruding therefrom.

8. An outer rotor motor according to claim 7, characterized in that: The heat dissipation ribs include internal heat dissipation ribs (411) and external heat dissipation ribs (412); the internal heat dissipation ribs (411) are located below the housing (31); the external heat dissipation ribs (412) are located outside the internal heat dissipation ribs (411); the internal heat dissipation ribs (411) are arranged in a plurality of concentric circles with the sleeve (42) as the center.

9. An outer rotor motor according to claim 8, characterized in that: The plurality of external heat dissipation ribs (412) are radially arranged with the sleeve (42) as the center.

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