Motor outer rotor assembly structure

Abstract

The utility model discloses a motor outer rotor assembly structure belongs to motor technical field, including rotor subassembly, and rotor subassembly includes a plurality of magnetic steel and sleeve ring, a plurality of magnetic steel evenly and interval distribution in the inner wall of sleeve ring, the axial both ends of magnetic steel all are located the inboard of sleeve ring axial both ends, and the integral structure is formed through injection molding between magnetic steel and sleeve ring, and the sleeve ring forms rotor shell with injection molding body. The scheme adopts the form of injection molding to form the integrated structure with magnetic steel and sleeve ring fixed, makes magnetic steel be stably fixed on the inboard wall of sleeve ring through injection molding pressure, and the fixing strength between magnetic steel and sleeve ring is greatly increased, guarantees the accuracy of the position between magnetic steel and sleeve ring, improves the structural strength of rotor shell and also guarantees the magnetic property of rotor shell.

Description

Technical Field

[0001] This utility model relates to an EC motor structure, and more specifically, to an external rotor assembly structure for a motor. Background Technology

[0002] In the outer rotor of an EC motor, magnets are arranged inside a seamless steel tube. The seamless steel tube is a magnetically conductive material, which can concentrate magnetic flux and reduce leakage of magnetic flux in non-working paths, thereby improving the utilization rate of the magnetic field. In existing EC motor outer rotors, magnets and seamless steel tubes are usually fixed in an embedded or surface-mount manner. Such fixing methods can easily cause magnets to detach from the surface of the steel tube, leading to motor failure and reducing the motor's service life. Furthermore, the scattered parts increase the assembly difficulty during motor assembly.

[0003] For example, Chinese Patent Publication No. CN107968499A, published on April 27, 2018, entitled "An External Rotor Motor," discloses an external rotor assembly structure for a motor, including a rotating shaft and a rotor assembly, such as a cylindrical housing, fixed to the rotating shaft, and several permanent magnets installed on the inner wall of the housing. The rotating shaft and the housing are fixedly connected, and the permanent magnets are fixed to the inner wall of the housing by adhesive. This connection method is insufficient to guarantee the fixing strength between the permanent magnets and the housing. During operation, it is easy for them to fall off or become displaced, reducing the performance of the motor. Utility Model Content

[0004] This invention overcomes the problem that existing magnets are prone to displacement inside the rotor housing, which affects motor performance. It provides an external rotor assembly structure for motors. This solution simplifies the structure of the motor rotor housing while improving the connection strength of the magnets and the overall performance of the motor.

[0005] To solve the above-mentioned technical problems, this utility model adopts the following technical solution: an external rotor assembly structure for a motor, including a rotor assembly, the rotor assembly including a plurality of magnets and a ring, the plurality of magnets being evenly and spaced apart on the inner wall of the ring, the axial ends of the magnets being located inside the axial ends of the rings, the magnets and the rings being integrally formed by injection molding, the injection molded body and the rings forming a rotor shell. This solution uses injection molding to fix the magnets and rings into an integral structure. The injection molding pressure stably fixes the magnets to the inner wall of the rings, significantly increasing the fixing strength between the magnets and the rings, ensuring the accuracy of the position between the magnets and the rings, improving the structural strength of the rotor shell while also ensuring the magnetic properties of the rotor shell. Since both ends of the magnets are located inside the ends of the rings, the injection molded material can be distributed at both axial ends of the magnets and the rings, effectively connecting and fixing both ends of the magnets and the rings.

[0006] Preferably, the rotor assembly further includes a shaft and a bushing. The shaft is fixed inside the bushing, and the bushing and the shaft are also fixed to the injection-molded body. The shaft and bushing are also injection-molded into an integral structure with the injection-molded body. That is, the shaft, bushing, magnet, and ring are connected by the injection-molded body to form an integrated structure. When the rotor rotates, it can drive the rotor shell formed by the magnet and ring to rotate.

[0007] Preferably, the bushing has a connecting portion on its circumferential outer side, the radial dimension of which is larger than the radial dimension of the bushing, and the connecting portion is in a quincunx shape. The connecting portion on the circumferential side of the bushing can form a connection with the injection molded body, and the quincunx design of the connecting portion can improve the connection strength between the connecting portion and the injection molded body, ensuring the overall strength of the rotor housing.

[0008] Preferably, the injection-molded part of the rotor assembly near the bushing is inclined. This inclined structure near the bushing allows for more heat dissipation space at the top of the motor, ensuring effective heat dissipation and thus improving motor performance.

[0009] Preferably, the inclined injection molded body is provided with a plurality of heat dissipation holes, which are evenly distributed in a ring on the injection molded body. The heat dissipation holes can effectively dissipate heat from the internal structure of the motor, ensuring good motor performance.

[0010] Preferably, the injection-molded body and the inner wall of the magnet are located on the same cylindrical surface. The fact that the injection-molded body and the annular inner wall formed by the magnet are located on the same cylindrical surface helps to prevent the unevenness of the injection-molded body from colliding and rubbing against the internal structure of the motor, and also reduces the air gap between the stator and rotor, thus improving the motor's performance.

[0011] Preferably, the rotor assembly has a notch at the end furthest from the bushing and between the adjacent magnet and the injection molded body. The notch between the adjacent magnets and between the injection molded body provides good support and positioning for the magnets.

[0012] Preferably, the raceway has a circumferentially seamless magnetically conductive structure. The seamless magnetically conductive structure of the raceway optimizes the magnetic circuit and improves the efficiency of the motor.

[0013] Preferably, the injection molded body is made of unsaturated resin BMC. Unsaturated resin BMC has good electrical and mechanical properties and is a thermosetting composite material that can ensure the structural strength of the motor rotor housing and the overall performance of the motor.

[0014] Compared with the prior art, the beneficial effects of this utility model are: (1) The rotor shell of this solution adopts a magnet and a ring to form an integrated structure through injection molding. The magnet does not need to be glued for fixation, which enhances the connection effect between the magnet and the ring, and also ensures the magnetic properties of the rotor shell; (2) It can reserve more heat dissipation space at the top of the motor to ensure the heat dissipation effect of the motor; (3) It can optimize the magnetic circuit structure of the motor and improve the performance of the motor. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the present invention.

[0016] Figure 2 This is a schematic diagram of the rotor housing of this utility model.

[0017] Figure 3 This is a bottom view of the rotor housing of this utility model.

[0018] Figure 4 for Figure 3 A cross-sectional view along the AA direction.

[0019] Figure 5 for Figure 3 Cross-sectional view along the BB direction.

[0020] In the diagram: 1. Magnet, 2. Collar, 3. Injection molded body, 4. Shaft, 5. Bushing, 6. Heat dissipation hole, 7. Notch, 8. Connecting part. Detailed Implementation

[0021] The technical solution of this utility model will be further described in detail below through specific embodiments and in conjunction with the accompanying drawings.

[0022] Example 1: As Figures 1 to 5 The diagram illustrates an external rotor assembly structure for an electric motor, comprising a rotor assembly, which includes several magnets 1, rings 2, and a shaft assembly. The rotor assembly is cylindrical in shape, as are the rings 2. The magnets 1 are tile-shaped (i.e., magnetic tiles). The outer circumferential surface of the magnets 1 is fitted to the inner circumferential surface of the rings 2, and the magnets 1 are evenly and circumferentially arranged on the inner side of the rings 2, with a certain gap between them. The shaft assembly is positioned along the axis of the rings 2 and the magnets 1. The shaft assembly, magnets 1, and rings 2 are connected as a whole by injection molding. Injection-molded bodies 3 are present at both axial ends of the rings 2, fixing the magnets 1 and rings 2 together. The top of the shaft assembly is connected to the tops of the magnets 1 and rings 2 via the injection-molded bodies 3. When the shaft assembly rotates, it drives the rings 2 and magnets 1 to rotate.

[0023] In this embodiment, four sets of magnets 1 are provided. The axial length of magnet 1 is less than the axial length of collar 2, and both ends of magnet 1 are located inside the axial ends of collar 2. That is, the top position of magnet 1 is lower than the top position of collar 2, and the bottom position of magnet 1 is higher than the bottom position of collar 2. This forms an annular stepped structure at both the top and bottom positions of magnet 1 and collar 2. When magnet 1 and collar 2 are placed into the mold for injection molding, the injection molded body 3 can press on the steps at both ends of magnet 1 and collar 2, increasing the filling amount of injection molded body 3 and the contact area between injection molded body 3 and magnet 1 and collar 2, ensuring that magnet 1 and collar 2 can be stably connected together, thus improving the performance of the motor's outer rotor. After injection molded body 3, magnet 1, and collar 2 are integrated to form the rotor shell, the positioning and assembly of magnet 1 is no longer required during the assembly process, greatly reducing the assembly difficulty of the EC motor.

[0024] Since the collar 2 and the magnet 1 are connected together by injection molding, the magnet 1 is firmly fixed to the inner surface of the collar 2 by the injection molding pressure. This can effectively prevent the magnet 1 from shifting during the use of the motor, which would cause uneven magnetic field, or from falling off and causing friction between the stator and rotor, which would lead to motor failure, reduce the service life of the motor and increase maintenance costs.

[0025] After the magnet 1 and the collar 2 are connected together by injection molding, the injection molded body 3 fills the gap between adjacent magnets 1 and the gap between magnet 1 and collar 2, thereby increasing the fixing strength of magnet 1 and collar 2. After injection molding is completed, the injection molded body 3 located between adjacent magnets 1 should be on the same cylindrical surface as the inner wall of magnet 1, that is, the inner wall of the rotor housing is a smooth cylindrical surface. This can prevent uneven injection molded body 3 from colliding and rubbing against the internal structure of the motor (stator assembly), and can also reduce the air gap between the stator and rotor, thereby improving the performance of the motor.

[0026] A notch 7 is provided at the bottom of the adjacent magnet 1. The notch 7 is not filled with the injection molded body 3. The notch 7 can provide good support and positioning for the magnet 1.

[0027] Furthermore, in this embodiment, the collar 2 is made of silicon steel or low carbon steel pipe structure, and the collar 2 is a magnetically conductive structure. The collar 2 has no splicing seam in the circumference. Such a collar 2 can optimize the magnetic circuit of the motor and improve the efficiency of the motor. The collar 2 can also serve as a mechanical protective layer to protect the magnet 1.

[0028] Preferably, in this embodiment, the material of the injection molded body 3 is unsaturated resin BMC. Unsaturated resin BMC has good electrical and mechanical properties and is a thermosetting composite material, which can ensure the structural strength of the motor rotor housing and the overall performance of the motor.

[0029] Example 2: As Figures 1 to 5 The diagram illustrates an external rotor assembly structure for an electric motor, comprising a rotor assembly, which includes several magnets 1, rings 2, and a shaft assembly. The rotor assembly is cylindrical in shape, as are the rings 2. The magnets 1 are tile-shaped (i.e., magnetic tiles). The outer circumferential surface of the magnets 1 is fitted to the inner circumferential surface of the rings 2, and the magnets 1 are evenly and circumferentially arranged on the inner side of the rings 2, with a certain gap between them. The shaft assembly is positioned along the axis of the rings 2 and the magnets 1. The shaft assembly, magnets 1, and rings 2 are connected as a whole by injection molding. Injection-molded bodies 3 are present at both axial ends of the rings 2, fixing the magnets 1 and rings 2 together. The top of the shaft assembly is connected to the tops of the magnets 1 and rings 2 via the injection-molded bodies 3. When the shaft assembly rotates, it drives the rings 2 and magnets 1 to rotate.

[0030] In this embodiment, four sets of magnets 1 are provided. The axial length of magnet 1 is less than the axial length of collar 2, and both ends of magnet 1 are located inside the axial ends of collar 2. That is, the top position of magnet 1 is lower than the top position of collar 2, and the bottom position of magnet 1 is higher than the bottom position of collar 2. This forms an annular stepped structure at both the top and bottom positions of magnet 1 and collar 2. When magnet 1 and collar 2 are placed into the mold for injection molding, the injection molded body 3 can press on the steps at both ends of magnet 1 and collar 2, increasing the filling amount of injection molded body 3 and the contact area between injection molded body 3 and magnet 1 and collar 2, ensuring that magnet 1 and collar 2 can be stably connected together, thus improving the performance of the motor's outer rotor. After injection molded body 3, magnet 1, and collar 2 are integrated to form the rotor shell, the positioning and assembly of magnet 1 is no longer required during the assembly process, greatly reducing the assembly difficulty of the EC motor.

[0031] Since the collar 2 and the magnet 1 are connected together by injection molding, the magnet 1 is firmly fixed to the inner surface of the collar 2 by the injection molding pressure. This can effectively prevent the magnet 1 from shifting during the use of the motor, which would cause uneven magnetic field, or from falling off and causing friction between the stator and rotor, which would lead to motor failure, reduce the service life of the motor and increase maintenance costs.

[0032] After the magnet 1 and the collar 2 are connected together by injection molding, the injection molded body 3 fills the gaps between adjacent magnets 1 and between magnet 1 and collar 2, thereby increasing the fixing strength between magnet 1 and collar 2. After injection molding is completed, the injection molded body will also be located on the inner side of the magnet, that is, the magnet is completely covered by the injection molded body. The inner wall of the rotor housing can be a smooth cylindrical surface. This can prevent the unevenness of the injection molded body 3 from colliding and rubbing against the internal structure of the motor (stator assembly), and can also reduce the air gap between the stator and rotor, thereby improving the performance of the motor.

[0033] A notch 7 is provided at the bottom of the adjacent magnet 1. The notch 7 is not filled with the injection molded body 3. The notch 7 can provide good support and positioning for the magnet 1.

[0034] The rotating shaft assembly includes a rotating shaft 4 and a bushing 5. The top of the rotating shaft 4 is fixedly connected to and passes through the bushing 5. The bushing 5 can improve the connection strength between the rotating shaft 4 and the injection molded body 3 and prevent the rotating shaft 4 from loosening. The top of the bushing 5 and the top of the rotating shaft 4 are also covered by the injection molded body 3, so that the rotating shaft 4, the bushing 5 and the injection molded body 3 form a stable connection.

[0035] A connecting portion 8 is provided on the outside of the bushing 5 and at its top. The connecting portion 8 is a connecting structure protruding from the outer periphery of the bushing 5. The connecting portion 8 has a quincunx-shaped structure, with alternating grooves and protrusions distributed circumferentially, thereby increasing the connection area between the connecting portion 8 and the injection molded body 3 and improving the connection strength between the injection molded body 3 and the rotating shaft assembly. Of course, the connecting portion 8 can also be designed in other shapes that can effectively increase the connection contact area.

[0036] In this embodiment, the collar 2 is made of silicon steel or low carbon steel pipe and is a magnetically conductive structure. The collar 2 has no splicing seam in the circumference. Such a collar 2 can optimize the magnetic circuit of the motor and improve the efficiency of the motor. The collar 2 can also serve as a mechanical protective layer to protect the magnet 1.

[0037] In this embodiment, the material of the injection molded body 3 is unsaturated resin BMC. Unsaturated resin BMC has good electrical and mechanical properties and is a thermosetting composite material that can ensure the structural strength of the motor rotor housing and the overall performance of the motor.

[0038] Example 3: As Figures 1 to 5The diagram illustrates an external rotor assembly structure for an electric motor, comprising a rotor assembly, which includes several magnets 1, rings 2, and a shaft assembly. The rotor assembly is cylindrical in shape, as are the rings 2. The magnets 1 are tile-shaped (i.e., magnetic tiles). The outer circumferential surface of the magnets 1 is fitted to the inner circumferential surface of the rings 2, and the magnets 1 are evenly and circumferentially arranged on the inner side of the rings 2, with a certain gap between them. The shaft assembly is positioned along the axis of the rings 2 and the magnets 1. The shaft assembly, magnets 1, and rings 2 are connected as a whole by injection molding. Injection-molded bodies 3 are present at both axial ends of the rings 2, fixing the magnets 1 and rings 2 together. The top of the shaft assembly is connected to the tops of the magnets 1 and rings 2 via the injection-molded bodies 3. When the shaft assembly rotates, it drives the rings 2 and magnets 1 to rotate.

[0039] In this embodiment, four sets of magnets 1 are provided. The axial length of magnet 1 is less than the axial length of collar 2, and both ends of magnet 1 are located inside the axial ends of collar 2. That is, the top position of magnet 1 is lower than the top position of collar 2, and the bottom position of magnet 1 is higher than the bottom position of collar 2. This forms an annular stepped structure at both the top and bottom positions of magnet 1 and collar 2. When magnet 1 and collar 2 are placed into the mold for injection molding, the injection molded body 3 can press on the steps at both ends of magnet 1 and collar 2, increasing the filling amount of injection molded body 3 and the contact area between injection molded body 3 and magnet 1 and collar 2, ensuring that magnet 1 and collar 2 can be stably connected together, thus improving the performance of the motor's outer rotor. After injection molded body 3, magnet 1, and collar 2 are integrated to form the rotor shell, the positioning and assembly of magnet 1 is no longer required during the assembly process, greatly reducing the assembly difficulty of the EC motor.

[0040] Since the collar 2 and the magnet 1 are connected together by injection molding, the magnet 1 is firmly fixed to the inner surface of the collar 2 by the injection molding pressure. This can effectively prevent the magnet 1 from shifting during the use of the motor, which would cause uneven magnetic field, or from falling off and causing friction between the stator and rotor, which would lead to motor failure, reduce the service life of the motor and increase maintenance costs.

[0041] After the magnet 1 and the collar 2 are connected together by injection molding, the injection molded body 3 fills the gaps between adjacent magnets 1 and between magnet 1 and collar 2, thereby increasing the fixing strength between magnet 1 and collar 2. After injection molding is completed, the injection molded body will also be located on the inner side of the magnet, that is, the magnet is completely covered by the injection molded body. The inner wall of the rotor housing can be a smooth cylindrical surface. This can prevent the unevenness of the injection molded body 3 from colliding and rubbing against the internal structure of the motor (stator assembly), and can also reduce the air gap between the stator and rotor, thereby improving the performance of the motor.

[0042] A notch 7 is provided at the bottom of the adjacent magnet 1. The notch 7 is not filled with the injection molded body 3. The notch 7 can provide good support and positioning for the magnet 1.

[0043] The rotating shaft assembly includes a rotating shaft 4 and a bushing 5. The top of the rotating shaft 4 is fixedly connected to and passes through the bushing 5. The bushing 5 can improve the connection strength between the rotating shaft 4 and the injection molded body 3 and prevent the rotating shaft 4 from loosening. The top of the bushing 5 and the top of the rotating shaft 4 are also covered by the injection molded body 3, so that the rotating shaft 4, the bushing 5 and the injection molded body 3 form a stable connection.

[0044] A connecting portion 8 is provided on the outside of the bushing 5 and at its top. The connecting portion 8 is a connecting structure protruding from the outer periphery of the bushing 5. The connecting portion 8 has a quincunx-shaped structure, with alternating grooves and protrusions distributed circumferentially, thereby increasing the connection area between the connecting portion 8 and the injection molded body 3 and improving the connection strength between the injection molded body 3 and the rotating shaft assembly. Of course, the connecting portion 8 can also be designed in other shapes that can effectively increase the connection contact area.

[0045] Furthermore, the top of the rotor assembly and the top of the magnet 1 and the collar 2 are inclined structures, that is, the top of the rotor housing is a truncated cone (frustum) structure, and the radial dimension of the injection body 3 gradually decreases from bottom to top. This can increase the space at the top of the rotor housing to a certain extent. This space forms a heat dissipation space with the upper part of the stator assembly. In addition, a number of heat dissipation holes 6 are provided on the injection body 3 at the top of the rotor housing. There are eight sets of heat dissipation holes 6. The heat dissipation holes 6 are evenly distributed in a ring on the injection body 3. The heat dissipation holes 6 are elliptical or waist-shaped. The length direction of the heat dissipation holes 6 is along the radial direction of the rotor housing. This can increase the diameter of the heat dissipation holes 6, thereby improving the heat dissipation effect of the heat dissipation holes 6.

[0046] In this embodiment, the collar 2 is made of silicon steel or low carbon steel pipe and is a magnetically conductive structure. The collar 2 has no splicing seam in the circumference. Such a collar 2 can optimize the magnetic circuit of the motor and improve the efficiency of the motor. The collar 2 can also serve as a mechanical protective layer to protect the magnet 1.

[0047] In this embodiment, the material of the injection molded body 3 is unsaturated resin BMC. Unsaturated resin BMC has good electrical and mechanical properties and is a thermosetting composite material that can ensure the structural strength of the motor rotor housing and the overall performance of the motor.

Claims

1. An external rotor assembly structure for an electric motor, characterized in that, The rotor assembly includes a plurality of magnets and a ring. The magnets are evenly and spaced apart on the inner wall of the ring. Both axial ends of the magnets are located inside the axial ends of the ring. The magnets and the ring are integrally formed by injection molding. The injection molded body and the ring form a rotor shell.

2. The motor external rotor assembly structure according to claim 1, characterized in that, The rotor assembly also includes a rotating shaft and a bushing, the rotating shaft being fixed inside the bushing, and the bushing and the rotating shaft being fixed to the injection molded body.

3. The motor external rotor assembly structure according to claim 2, characterized in that, The bushing has a connecting part on its circumferential outer side. The radial dimension of the connecting part is larger than the radial dimension of the bushing. The connecting part is shaped like a plum blossom.

4. The motor external rotor assembly structure according to claim 3, characterized in that, The injection-molded part of the rotor assembly near the bushing end is inclined.

5. The motor external rotor assembly structure according to claim 4, characterized in that, The inclined injection molded body is provided with a number of heat dissipation holes, which are evenly distributed in a ring on the injection molded body.

6. A motor external rotor assembly structure according to any one of claims 1 to 5, characterized in that, The injection-molded body and the inner wall of the magnet are located on the same cylindrical surface.

7. A motor external rotor assembly structure according to any one of claims 2 to 5, characterized in that, The rotor assembly is located at one end away from the bushing and has a notch formed between the adjacent magnet and the injection molded body.

8. A motor external rotor assembly structure according to any one of claims 1 to 5, characterized in that, The collar is a circumferentially seamless magnetically conductive structure.

9. A motor external rotor assembly structure according to any one of claims 1 to 5, characterized in that, The injection molded part is made of unsaturated resin BMC.

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