Oil-cooled outer rotor motor

Abstract

The invention discloses an oil-cooled external rotor motor, which comprises a stator and a rotor rotatably sleeved on the stator, and is characterized in that the stator comprises a stator support and an iron core assembly sleeved on the stator support; the iron core assembly comprises a yoke part arranged on the stator support in a sleeving mode, a plurality of tooth parts connected to the yoke part in a sliding mode and a plurality of windings wound around the tooth parts, a cooling flow channel is formed in the stator support, and cooling oil is circularly arranged in the stator support. The rotor comprises a cylindrical rotor shell with two open ends and a plurality of magnets arranged on the inner wall of the rotor shell, the two open ends of the rotor shell are connected with end plates respectively, each end plate is of an annular structure, the inner wall of each end plate protrudes to form an annular first boss, and the first bosses are connected to the stator support in a rotating and sealing mode. According to the oil-cooled outer rotor motor, the iron core assembly is directly cooled through cooling oil, the heat dissipation effect is improved, the tooth part and yoke part separated structure is adopted, the slot fullness rate is increased, and the torque density of the motor is improved.

Description

Technical Field

[0001] This application relates to the field of electric motor technology, and in particular to an oil-cooled external rotor motor. Background Technology

[0002] External rotor motors, with their unique structure of external rotor and internal stator, are widely used in low-speed, high-torque applications. They are direct-drive motors with high power and torque densities and are suitable for automotive hub motors and EVTOL motors. However, considering that the main factors affecting motor power and torque densities in the current market are heat dissipation and slot fill factor, conventional air and water cooling cannot directly and effectively cool the motor windings, making it difficult to significantly improve power density. Furthermore, if cooling oil is circulated directly into the motor, the high-speed rotation of the rotor will cause severe impact and friction on the winding surface, affecting the winding's lifespan. Currently, the cores of mainstream external rotor motors are made of silicon steel sheets that are stamped and stacked as a single piece, with the teeth and yoke also being integrally formed. This means that large-section flat wires cannot be embedded in the core slots, resulting in a very low slot fill factor for manually wound round wires, further affecting the improvement of the motor's torque density. In addition, the current market trend of motor cores using a separate tooth and yoke structure often employs a parallel dovetail slot structure, which carries the risk of vibration, loosening, or displacement during motor operation. Summary of the Invention

[0003] The purpose of this invention is to provide an oil-cooled external rotor motor to overcome the shortcomings of the prior art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: This application discloses an oil-cooled external rotor motor, including a stator and a rotor rotatably mounted on the stator. The stator includes a stator support and an iron core assembly mounted on the stator support. The iron core assembly includes a yoke mounted on the stator support, a plurality of teeth slidably connected to the yoke, and a plurality of windings wound around the teeth. The stator support has a cooling channel and is circulated with cooling oil. The rotor includes a cylindrical rotor shell with openings at both ends and a plurality of magnets disposed on the inner wall of the rotor shell. The two ends of the openings of the rotor shell are respectively connected to end plates. The end plates have an annular structure, and their inner walls have an annular first boss protruding from them. The first boss is rotatably and sealingly connected to the stator support.

[0005] Furthermore, in the aforementioned oil-cooled external rotor motor, the cooling channel includes an oil inlet ring and an oil outlet ring respectively recessed on the outer wall of the stator support, and a plurality of oil inlet holes and oil outlet holes disposed on the inner wall of the stator support. The oil inlet holes are connected to the oil inlet ring, and the oil outlet holes are connected to the oil outlet ring.

[0006] Furthermore, in the aforementioned oil-cooled external rotor motor, the side of the oil inlet ring away from the oil outlet ring is connected to several outlet channels, and the side of the oil outlet ring away from the oil inlet ring is connected to several inlet channels.

[0007] Furthermore, in the aforementioned oil-cooled external rotor motor, a positioning boss corresponding to the yoke protrudes from one end of the outer wall of the stator support, and the outgoing or incoming flow channel extends to the positioning boss.

[0008] Furthermore, in the aforementioned oil-cooled external rotor motor, the outer wall of the yoke is provided with a plurality of insertion slots along its axial direction, and the toothed part protrudes from one end near the yoke, the insertion part being slidably inserted into the corresponding insertion slot.

[0009] Furthermore, in the aforementioned oil-cooled external rotor motor, the insertion slot is a tapered structure with gradually increasing width along its length, and its larger end is close to the positioning boss.

[0010] Furthermore, in the aforementioned oil-cooled external rotor motor, the stator support has annular sealing grooves recessed at both ends, and the first boss is rotatably sealed within the sealing groove by a bearing and a skeleton sealing ring.

[0011] Furthermore, in the aforementioned oil-cooled external rotor motor, the surface of the teeth is fitted with an insulating sleeve with openings at both ends.

[0012] Furthermore, in the aforementioned oil-cooled external rotor motor, an outer ring boss protrudes from the outer wall of the end of the insulating sleeve near the magnet, and adjacent outer ring bosses are respectively sealed and connected.

[0013] Furthermore, in the aforementioned oil-cooled external rotor motor, the two ends of the outer ring boss are respectively sealed with inner covers, the inner covers are annular structures, and their inner rings are sealed to the stator support.

[0014] Compared with the prior art, the advantages of the present invention are: the oil-cooled external rotor motor directly cools the iron core assembly through cooling oil, improving the heat dissipation effect; the tooth and yoke are separated, increasing the slot fill factor and improving the motor torque density. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1The diagram shown is a structural schematic of an oil-cooled external rotor motor in a specific embodiment of the present invention.

[0017] Figure 2 The diagram shown is an exploded view of an oil-cooled external rotor motor in a specific embodiment of the present invention.

[0018] Figure 3 The image shown is an exploded view of an oil-cooled external rotor motor according to a specific embodiment of the present invention.

[0019] Figure 4 The diagram shown is an exploded view of the magnet and stator in a specific embodiment of the present invention.

[0020] Figure 5 The diagram shown is a structural schematic of the stator support in a specific embodiment of the present invention.

[0021] Figure 6 The diagram shown is a structural schematic of the yoke in a specific embodiment of the present invention.

[0022] Figure 7 The diagram shown is a schematic representation of the assembly of the teeth, insulating sleeve, and winding in a specific embodiment of the present invention.

[0023] Figure 8 The diagram shown is an exploded view of the teeth and insulating sleeve in a specific embodiment of the present invention. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0026] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "coupling" 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.

[0027] As shown Figures 1 to 8 in the figure, an oil-cooled outer rotor motor includes a stator and a rotor rotatably sleeved on the stator. The stator includes a stator bracket 1 and a core assembly sleeved on the stator bracket 1. The core assembly includes a yoke portion 2 sleeved on the stator bracket 1, a plurality of tooth portions 3 slidably connected to the yoke portion 2, and a plurality of windings 4 wound around the tooth portions 3. A cooling flow channel 11 is provided in the stator bracket 1, and cooling oil is circulated therein. The rotor includes a cylindrical rotor housing 5 with openings at both ends and a plurality of magnets 6 provided on the inner wall of the rotor housing 5. End plates 7 are respectively connected to the two open ends of the rotor housing 5. The end plates 7 are of an annular structure, and an annular first boss 71 protrudes from the inner wall thereof. The first boss 71 is rotationally and sealingly connected to the stator bracket 1.

[0028] In this technical solution, the magnets are conventional square or arc-shaped permanent magnets, etc., and are uniformly distributed on the inner wall of the rotor housing in a conventional form such as embedding / gluing. Through the interaction between the magnets and the core assembly, the magnets, the rotor housing, and the end plates are driven to rotate. The end plates are fixed to the corresponding ends of the rotor housing by conventional bolts, etc. An annular sealing boss protrudes from the inner wall (side wall close to the rotor housing) of the end plate and is embedded in the inner wall of the rotor housing, and a conventional sealing ring or gasket, etc. is provided to achieve a sealed connection; the tooth portion and the yoke portion are provided in a split manner, which is convenient for winding the windings around the tooth portion, avoiding interference of the yoke portion and interference between adjacent tooth portions with respect to the winding of the corresponding windings, that is, improving the slot filling factor of the motor, thereby enhancing the torque density of the motor.

[0029] Exemplarily, referring to Figures 1 to 5 the figure, the cooling flow channel 11 includes an oil inlet ring 111 and an oil outlet ring 112 respectively recessed in the outer wall of the stator bracket 1, and a plurality of oil inlet holes 113 and oil outlet holes 114 provided in the inner wall of the stator bracket 1. The oil inlet holes 113 are connected to the oil inlet ring 111, and the oil outlet holes 114 are connected to the oil outlet ring 112.

[0030] In this technical solution, the stator support is a conventional hollow shaft structure. The oil inlet and outlet are connected to an external circulating pump or other device through conventional pipe joints and oil pipes. Cooling oil enters the oil inlet ring through the oil inlet and flows towards the teeth and windings, and then flows out through the oil outlet ring and oil outlet, carrying away the heat of the windings. The outer wall of the stator support is machined with two spaced annular grooves, which are used as the oil inlet ring and the oil outlet ring, respectively. The cooling oil flowing out of the oil inlet ring flows through the gaps in the windings to the oil outlet ring, carrying away the heat of the windings. The stator support can also be a conventional double-layer structure, including an inner ring and an outer ring arranged coaxially and a connecting rib connecting the inner ring and the outer ring. The yoke is fitted onto the outer wall of the outer ring, and the cooling channel is also set in the outer ring.

[0031] For example, see Figures 1 to 5 As shown, the side of the oil inlet ring 111 away from the oil outlet ring 112 is connected to several outlet channels 115, and the side of the oil outlet ring 112 away from the oil inlet ring 111 is connected to several inlet channels 116.

[0032] In this technical solution, several axial grooves are machined at both ends of the outer wall of the oil inlet ring and connected to the corresponding oil inlet ring or oil outlet ring, serving as the outlet flow channel and the inlet flow channel. After the cooling oil enters the oil inlet ring, it flows quickly to the winding through the outlet flow channel, and flows to the side where the oil outlet ring is located through the gap of the winding, and then flows into the oil outlet ring through the inlet flow channel.

[0033] For example, see Figures 2 to 6 As shown, a positioning boss 12 corresponding to the yoke 2 protrudes from the outer wall of one end of the stator support 1, and the outflow channel 115 or the inflow channel 116 extends to the positioning boss 12.

[0034] In this technical solution, the yoke is fitted onto the stator bracket via an interference fit or other means. The locating boss facilitates quick and easy positioning of the yoke's installation position; that is, the end face of the yoke closest to the locating boss abuts against the locating boss. To prevent rotation between the yoke and the locating bracket, a limiting strip protrudes from the inner wall of the yoke, and a limiting groove is recessed on the outer wall of the locating bracket. When the yoke is fitted onto the stator bracket, the limiting strip slides into the limiting groove. The locating boss and the winding are spaced apart to avoid interference with the installation of the teeth. The outlet or inlet flow channel extends into the locating boss to improve the smoothness of the cooling oil flow. The positions of the oil inlet ring and the oil outlet ring can be interchanged, with the outlet or inlet flow channel corresponding to the locating boss extending into the locating boss.

[0035] For example, see Figures 2 to 8 As shown, the outer wall of the yoke 2 is provided with several insertion grooves 21 along its axial direction, and the tooth 3 has an insertion part 31 protruding from one end near the yoke 2. The insertion part 31 is slidably inserted into the corresponding insertion groove 21.

[0036] In this technical solution, the teeth can be slidably inserted into the insertion slot to complete the installation of the yoke, which simplifies the installation structure. The teeth can be installed before the yoke to complete the winding of the corresponding winding, which provides a large operating space. Increasing the number of turns of the winding can improve the slot fill factor of the motor.

[0037] For example, see Figures 2 to 8 As shown, the insertion slot 21 has a tapered structure with gradually increasing width along its length, and its large end is close to the positioning boss 12.

[0038] In this technical solution, the cross-section of the insertion slot is a conventional structure such as dovetail, trapezoid, arc, or ellipse, and it is a tapered structure with gradually increasing width along its length. The insertion part of the tooth corresponds to the insertion slot. That is, as the depth of the insertion part inserted into the insertion slot increases, the insertion part and the insertion slot fit more and more tightly until the insertion part and the insertion slot are directly and tightly fitted and fixed, improving the installation accuracy. The large end of the insertion slot (the end with the larger opening width) is set close to the positioning boss. After the yoke is installed on the positioning bracket, the positioning boss seals the large end of the insertion slot to prevent the teeth from shaking.

[0039] For example, see Figures 1 to 5 As shown, the stator support 1 has annular sealing grooves at both ends, and the first boss 71 is rotatably sealed in the sealing groove by bearing 8 and skeleton sealing ring 9.

[0040] In this technical solution, the bearing and skeleton seal ring can be directly utilized from the existing structure. The bearing and skeleton seal ring can achieve rotational sealing of the end plate and stator support, reducing the possibility of cooling oil leakage.

[0041] For example, see Figures 2 to 5 as well as Figure 7 and Figure 8 As shown, the surface of the tooth 3 is fitted with an insulating sleeve 10 with openings at both ends.

[0042] In this technical solution, the insulating sleeve is formed by conventional processes such as injection molding and is fitted onto the surface of the teeth, and the winding is wound around the surface of the insulating sleeve.

[0043] For example, see Figures 2 to 5 as well as Figure 7 and Figure 8 As shown, the outer walls of the insulating sleeve 10 have inner ring bosses 101 and outer ring bosses 102 protruding from both ends, and adjacent outer ring bosses 102 are sealed together.

[0044] In this technical solution, a pole shoe is provided at the outer end of the tooth (the end opposite to the yoke), and a positioning groove corresponding to the pole shoe is provided in the outer ring boss. The pole shoe is embedded in the positioning groove to improve the installation accuracy of the insulating sleeve and the tooth. Adjacent outer ring bosses are sealed and connected by conventional methods such as butt bonding, overlapping bonding, or groove tight-fitting bonding. The cooling oil is guided to flow from the oil inlet ring to the oil outlet ring through the winding gap, increasing the contact between the cooling oil and the winding and improving the heat dissipation effect. The inner ring boss physically isolates the winding and the yoke.

[0045] For example, see Figures 2 to 5 as well as Figure 7 and Figure 8 As shown, the two ends of the outer ring boss 102 are respectively sealed and connected to the inner cover 20. The inner cover 20 has an annular structure and the inner wall has a connecting boss. The connecting boss is sealed and embedded in the stator bracket 1.

[0046] In this technical solution, the inner wall of the inner cover (the side wall near the teeth) has an annular second protrusion protruding from its outer ring. The second protrusion has an annular groove recessed within it, which engages with the corresponding end of the outer ring protrusion and is sealed using conventional sealing rings, gaskets, or adhesives. The inner wall of the inner cover has a connecting protrusion protruding from its inner ring and embedded in the stator support, guiding the cooling oil through the winding gap from the oil inlet ring to the oil outlet ring, increasing the contact between the cooling oil and the winding, and improving the heat dissipation effect. The teeth are made of stacked silicon steel sheets, and adjacent silicon steel sheets and the silicon steel sheets and the insulating sleeve are sealed by adhesives or other means. There is no cooling oil between the air gap and the rotor housing. Even when the motor rotates at high speed, the cooling oil inside the motor will not be agitated and centrifugally rotated, thus avoiding friction damage to the teeth and windings. When reducing costs and simplifying the production process, the adjacent silicon steel sheets and the silicon steel sheets and the insulating sleeve may not be sealed. That is, the cooling oil fills the space between the air gap and the rotor housing. Even when the motor rotates at high speed, the cooling oil between the windings will not be agitated and centrifugally rotated, thus reducing friction damage to the windings. At the same time, the cooling oil filling the space between the air gap and the rotor housing can also cool the rotor.

[0047] In summary, this oil-cooled external rotor motor improves heat dissipation by directly cooling the iron core assembly with cooling oil, and its separate tooth and yoke structure increases slot fill factor and improves motor torque density.

[0048] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0049] The above description is only a specific embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. An oil-cooled external rotor motor, characterized in that, The system includes a stator and a rotor rotatably mounted on the stator. The stator includes a stator support and an iron core assembly mounted on the stator support. The iron core assembly includes a yoke mounted on the stator support, several teeth slidably connected to the yoke, and several windings wound around the teeth. The stator support has cooling channels and circulating cooling oil. The rotor includes a cylindrical rotor shell with openings at both ends and several magnets disposed on the inner wall of the rotor shell. End plates are respectively connected to the two ends of the rotor shell openings. The end plates have annular structures and annular first bosses protruding from their inner walls. The first bosses are rotatably and sealingly connected to the stator support.

2. The oil-cooled external rotor motor according to claim 1, characterized in that: The cooling channel includes an oil inlet ring and an oil outlet ring respectively recessed on the outer wall of the stator support, and a plurality of oil inlet holes and oil outlet holes disposed on the inner wall of the stator support. The oil inlet holes are connected to the oil inlet ring, and the oil outlet holes are connected to the oil outlet ring.

3. The oil-cooled external rotor motor according to claim 2, characterized in that: The side of the oil inlet ring away from the oil outlet ring is connected to several outlet channels, and the side of the oil outlet ring away from the oil inlet ring is connected to several inlet channels.

4. The oil-cooled external rotor motor according to claim 3, characterized in that: One end of the stator support has a positioning boss protruding from its outer wall, which corresponds to the yoke portion, and the outflow channel or inflow channel extends to the positioning boss.

5. The oil-cooled external rotor motor according to claim 4, characterized in that: The outer wall of the yoke is provided with a plurality of insertion grooves along its axial direction, and the toothed part has an insertion part protruding from one end near the yoke, the insertion part being slidably inserted into the corresponding insertion groove.

6. The oil-cooled external rotor motor according to claim 5, characterized in that: The insertion slot is a tapered structure with gradually increasing width along its length, and its larger end is close to the positioning boss.

7. The oil-cooled external rotor motor according to claim 1, characterized in that: The stator support has annular sealing grooves at both ends, and the first boss is rotatably sealed in the sealing groove by a bearing and a skeleton sealing ring.

8. The oil-cooled external rotor motor according to claim 1, characterized in that: The surface of the teeth is fitted with an insulating sleeve that is open at both ends.

9. The oil-cooled external rotor motor according to claim 8, characterized in that: The outer wall of the insulating sleeve near the magnet has an outer ring boss protruding from it, and adjacent outer ring bosses are respectively sealed and connected.

10. The oil-cooled external rotor motor according to claim 9, characterized in that: The outer ring boss has inner covers sealed to both ends. The inner covers are annular structures and their inner rings are sealed to the stator support.

Images