A brushless motor and a rotor assembly thereof

Abstract

The utility model discloses a rotor assembly of brushless motor, including rotor core, front balance block, rear balance block and pivot, front balance block is connected in the front end surface of rotor core and is provided with first balance hole, rear balance block is connected in the back end surface of rotor core and is provided with second balance hole, and the pivot is worn in rotor core, front balance block and rear balance block, wherein, front balance block and rear balance block are the balance block of adopting the plastic material quality preparation formation respectively, the one end of rear balance block away from rotor core still integrative forming connection has the radiating fan blade, and the radiating fan blade is configured as can rotate with rear balance block and makes the radiating wind flow from the back end surface of rotor core to the front end surface. The scheme of the present application can reduce the distance of radiating fan blade and rotor core to improve the heat dissipation performance, can also avoid destroying the dynamic balance state of rotor assembly due to increasing the installation of radiating fan blade, further can reduce the overall weight of motor, reduce the cost.

Description

Technical Field

[0001] This utility model relates to the field of electric motor technology, and in particular to a brushless motor and its rotor assembly. Background Technology

[0002] Current brushless motor cooling methods involve installing cooling fan blades at the tail end of the motor shaft. However, the distance between the cooling fan blades and the rotor core is relatively large, resulting in insufficient cooling efficiency. Furthermore, to maintain rotor balance at high speeds, existing rotor assemblies typically include metal (e.g., copper or aluminum alloy) balance weights on both ends of the rotor core. After balancing the rotor assembly, plastic cooling fan blades are then installed at the tail end of the motor shaft. Adding these additional cooling fan blades disrupts the dynamic balance of the rotor assembly, negatively impacting the brushless motor's performance. Utility Model Content

[0003] In view of this, the purpose of this utility model is to provide a brushless motor and its rotor assembly that can optimize heat dissipation and dynamic balance performance.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: This utility model first provides a rotor assembly for a brushless motor. The rotor assembly includes a rotor core, a front balance block, a rear balance block, and a shaft. The front balance block is connected to the front end face of the rotor core and has a first balance hole. The rear balance block is connected to the rear end face of the rotor core and has a second balance hole. The shaft passes through the rotor core, the front balance block, and the rear balance block. The front and rear balance blocks are made of plastic. A cooling fan is integrally formed on the end of the rear balance block facing away from the rotor core. The cooling fan is configured to rotate with the rear balance block, allowing cooling air to flow from the rear end face of the rotor core towards the front end face.

[0005] In the specific embodiment, the edge of the rear balance block has a cylindrical connecting portion extending axially, and the end of the cylindrical connecting portion has a radially extending annular connecting portion. The heat dissipation fan blades are formed on one side surface of the annular connecting portion facing the rear balance block, and a plurality of the heat dissipation fan blades are arranged in a circumferential array around the outer wall of the cylindrical connecting portion.

[0006] In the specific design, the rotor core has a first shaft hole at its center that matches the rotating shaft. The rotor core also has multiple axially penetrating positioning holes arranged in a circular array around the first shaft hole. The front balance block has a second shaft hole at its center that matches the rotating shaft. On the surface of the front balance block facing the rotor core, a first positioning post is positioned between any two adjacent first balance holes. The total number of first balance holes and first positioning posts is the same as the number of positioning holes and they are arranged in a one-to-one correspondence. The rear balance block has a third shaft hole at its center that matches the rotating shaft. On the surface of the block facing the rotor core, a second positioning post is provided between any two adjacent second balance holes. The total number of the second balance holes and the second positioning posts is the same as the number of positioning holes and they are arranged in a one-to-one correspondence. The first positioning post is inserted into the positioning hole from the front end face of the rotor core with an interference fit, and the second positioning post is inserted into the positioning hole from the rear end face of the rotor core with an interference fit. The positioning hole that is inserted into the first positioning post communicates with the second balance hole on the rear end face of the rotor core, and the positioning hole that is inserted into the second positioning post communicates with the first balance hole on the front end face of the rotor core.

[0007] In the specific design, the rotor core is provided with 6 positioning holes, the front balance block is provided with 3 first balance holes and 3 first positioning posts, and the rear balance block is provided with 3 second balance holes and 3 second positioning posts.

[0008] In the specific solution, a plurality of first sector-shaped grooves are formed on the surface of the front balance block away from the rotor core. The plurality of first sector-shaped grooves are arranged in a circumferential array around the second shaft hole, and the first balance hole is opened in the first sector-shaped groove.

[0009] In the specific embodiment, a plurality of second sector-shaped grooves are formed on the surface of the rear balance block away from the rotor core. The plurality of second sector-shaped grooves are arranged in a circumferential array around the third shaft hole, and the second balance hole is opened in the second sector-shaped groove.

[0010] In the specific design, a magnet is installed in the rotor core, and a weight reduction hole is also provided between any two adjacent positioning holes.

[0011] This utility model also provides a brushless motor, including a housing and a motor body installed in the housing. The motor body includes a stator assembly and a rotor assembly as described above. The stator assembly is fixedly connected to the housing, and the rotor assembly passes through the stator assembly and rotates in cooperation with the stator assembly.

[0012] The brushless motor and its rotor assembly provided in this embodiment of the present invention have the following advantages compared with the prior art: First, the cooling fan is integrally formed and connected to the rear balance block. On the one hand, this can reduce the distance between the cooling fan and the rotor core, thereby improving the heat dissipation performance. On the other hand, when the front and rear balance blocks are assembled onto the rotor core and their dynamic balance is adjusted, the influence of the cooling fan is taken into account, avoiding the need to add cooling fan after the rotor assembly is balanced, which would damage its dynamic balance performance. Second, the front and rear balance blocks are made of plastic material, which can reduce the overall weight of the motor and lower the cost. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the rotor assembly in this utility model; Figure 2 This is a cross-sectional view of the rotor assembly in this utility model; Figure 3 This is an exploded view of the rotor assembly in this utility model; Figure 4 This is a schematic diagram of the rotor core in this utility model; Figure 5 This is a first-view structural schematic diagram of the front balancing block in this utility model; Figure 6 This is a second-view structural schematic diagram of the front balancing block in this utility model; Figure 7 This is a first-view structural schematic diagram of the rear balancing block in this utility model; Figure 8 This is a second-view structural schematic diagram of the rear balancing block in this utility model; Figure 9 This is a schematic diagram of the structure of the motor body in this utility model. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of this utility model clearer, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Examples of these preferred embodiments are illustrated in the drawings. The embodiments of this utility model shown in and described with reference to the drawings are merely exemplary, and this utility model is not limited to these embodiments.

[0015] It should be noted that the same or similar reference numerals in the accompanying drawings of the embodiments of this utility model correspond to the same or similar components. In the description of this utility model, it should be understood that if terms such as "upper," "lower," "left," and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, they are only for the convenience of describing this utility model and 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, the terms used to describe positional relationships in the accompanying drawings are only for illustrative purposes and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0016] It should also be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and / or processing steps closely related to the solution according to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0017] This utility model embodiment first provides a rotor assembly for a brushless motor, see reference. Figures 1 to 8 The rotor assembly 1 mainly includes a rotor core 11, a front balance block 12, a rear balance block 13, and a rotating shaft 14. The front balance block 12 is connected to the front end face of the rotor core 11 and has a first balance hole 121. The rear balance block 13 is connected to the rear end face of the rotor core 11 and has a second balance hole 131. The rotating shaft 14 passes through the rotor core 11, the front balance block 12, and the rear balance block 13. The front balance block 12 and the rear balance block 13 are balance blocks made of plastic material. The rear balance block 13 is also integrally connected to a heat dissipation fan 151 at the end opposite to the rotor core 11. The heat dissipation fan 151 is configured to rotate with the rear balance block 13 so that the heat dissipation air flows from the rear end face of the rotor core 11 toward the front end face.

[0018] Specifically, the edge of the rear balance block 13 has an axially extending cylindrical connecting portion 152, and the end of the cylindrical connecting portion 152 has a radially extending annular connecting portion 153. The heat dissipation fan blades 151 are formed on one side surface of the annular connecting portion 153 facing the rear balance block 13, and a plurality of the heat dissipation fan blades 151 are arranged in a circumferential array around the outer side wall of the cylindrical connecting portion 152.

[0019] As described above, the rotor assembly 1 is used in the motor structure. When rotating at high speed, the rotor core 11 drives the rear balance block 13 to rotate. The integrally formed cooling fan blade 151 rotates with the rear balance block 13, thereby directing the cooling air from the rear end face of the rotor core 11 toward the front end face to cool down the rotor assembly 1 and the stator assembly that cooperates with the rotor assembly 1.

[0020] Based on the rotor assembly 1 with the above structure: First, the heat dissipation fan 151 is integrally formed and connected to the rear balance block 13. On the one hand, this can reduce the distance between the heat dissipation fan 151 and the rotor core 11, thereby improving heat dissipation performance. On the other hand, when the front balance block 12 and the rear balance block 13 are assembled onto the rotor core 11 and their dynamic balance is adjusted, the influence factors of the heat dissipation fan 151 are taken into account, avoiding the need to add heat dissipation fan after the rotor assembly 1 has been balanced, which would damage its dynamic balance performance. Second, the front balance block 12 and the rear balance block 13 are balance blocks made of plastic material, which can reduce the overall weight of the motor and reduce costs.

[0021] In the specific solution, the rotor core 11 is provided with a first shaft hole 111 that is compatible with the rotating shaft 14 at the center position. The rotor core 11 is also provided with a plurality of positioning holes 112 that are axially connected. The plurality of positioning holes 112 are arranged in a circular array around the first shaft hole 111.

[0022] In the specific solution, a second shaft hole 122 that is adapted to the rotating shaft 14 is provided at the center of the front balance block 12. On the surface of the front balance block 12 facing the rotor core 11, a first positioning post 123 is provided between any two adjacent first balance holes 121. The total number of the first balance holes 121 and the first positioning post 123 is the same as the number of the positioning holes 112 and they are provided in a one-to-one correspondence.

[0023] In the specific scheme, the center position of the rear balance block 13 is provided with a third shaft hole 132 that is compatible with the rotating shaft 14. On the surface of the rear balance block 13 facing the rotor core 11, a second positioning post 133 is provided between any two adjacent second balance holes 131. The total number of the second balance holes 131 and the second positioning post 133 is the same as the number of the positioning holes 112 and they are set in a one-to-one correspondence.

[0024] When the front balancing block 12 and the rear balancing block 13 are assembled onto the rotor core 11, the first positioning post 123 is inserted into the positioning hole 112 through an interference fit from the front end face of the rotor core 11, and the second positioning post 133 is inserted into the positioning hole 112 through an interference fit from the rear end face of the rotor core 11. Furthermore, the positioning hole 112 that is inserted into the first positioning post 123 communicates with the second balancing hole 131 on the rear end face of the rotor core 11, and the positioning hole 112 that is inserted into the second positioning post 133 communicates with the first balancing hole 121 on the front end face of the rotor core 11.

[0025] As a specific example, in this embodiment, the rotor core 11 has six positioning holes 112, the front balance block 12 has three first balance holes 121 and three first positioning posts 123, and the rear balance block 13 has three second balance holes 131 and three second positioning posts 133. The three first positioning posts 123 are inserted into the three positioning holes 112 on the front end face of the rotor core 11, and these three positioning holes 112 communicate with the three second balance holes 131 in the rear balance block 13 on the rear end face of the rotor core 11. The three second positioning posts 133 are inserted into the other three positioning holes 112 on the rear end face of the rotor core 11, and these three positioning holes 112 communicate with the three first balance holes 121 in the front balance block 12 on the front end face of the rotor core 11. That is, the positioning holes 112 that are inserted into the first positioning post 123 and the positioning holes 112 that are inserted into the second positioning post 133 are arranged alternately on the rotor core 11, thereby better maintaining the dynamic balance of the rotor assembly.

[0026] Furthermore, such as Figure 4 As shown, a magnet 113 is installed in the rotor core 11, and a weight reduction hole 114 is also provided between any two adjacent positioning holes 112.

[0027] In this preferred embodiment, as a preferred solution, such as Figure 5 As shown, a plurality of first sector-shaped grooves 124 are formed on the surface of the front balance block 12 facing away from the rotor core 11. These first sector-shaped grooves 124 are arranged in a circumferential array around the second shaft hole 122, and the first balance hole 121 is formed within one of the first sector-shaped grooves 124. Further, as... Figure 7As shown, a plurality of second sector-shaped grooves 134 are formed on the surface of the rear balance block 13 away from the rotor core 11. The plurality of second sector-shaped grooves 134 are arranged in a circumferential array around the third shaft hole 132, and the second balance hole 131 is opened in the second sector-shaped grooves 134.

[0028] When assembling the front balance block 12 and the rear balance block 13 onto the rotor core 11 and performing dynamic balancing on the rotor assembly 1, adjustments can be made by adding balancing material to the first balance hole 121 and the first sector groove 124, as well as the second balance hole 131 and the second sector groove 134.

[0029] Based on the rotor assembly 1 provided in the above embodiment, this embodiment also provides a brushless motor, see reference. Figure 9 The brushless motor mainly includes a housing (not shown in the attached drawings) and a motor body 100 installed within the housing. The motor body 100 includes a stator assembly 2 and a rotor assembly 1. The stator assembly 2 is fixedly connected to the housing, and the rotor assembly 1 passes through the stator assembly 2 and rotatably engages with it. Bearings are installed within the housing, and both ends of the rotating shaft 14 in the rotor assembly 1 pass through one of the bearings.

[0030] In summary, the brushless motor and its rotor assembly provided in the above embodiments of this utility model have front and rear balance blocks made of plastic. The rear balance block has a heat dissipation fan integrally formed and connected to the end opposite to the rotor core. This reduces the distance between the heat dissipation fan and the rotor core, thereby improving heat dissipation performance. It also avoids disrupting the dynamic balance of the rotor assembly by adding heat dissipation fan. Furthermore, it reduces the overall weight of the motor and lowers the cost.

[0031] 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. A rotor assembly for a brushless motor, characterized in that, The rotor assembly (1) includes a rotor core (11), a front balance block (12), a rear balance block (13), and a shaft (14). The front balance block (12) is connected to the front end face of the rotor core (11) and has a first balance hole (121). The rear balance block (13) is connected to the rear end face of the rotor core (11) and has a second balance hole (131). The shaft (14) passes through the rotor core (11). 1) The front balance block (12) and the rear balance block (13); wherein the front balance block (12) and the rear balance block (13) are balance blocks made of plastic material, and the rear balance block (13) is integrally connected to a heat dissipation fan (151) at the end opposite to the rotor core (11). The heat dissipation fan (151) is configured to rotate with the rear balance block (13) so that the heat dissipation air flows from the rear end face of the rotor core (11) toward the front end face.

2. The rotor assembly according to claim 1, characterized in that, The rear balance block (13) has an axially extending cylindrical connecting portion (152) at its edge, and an annular connecting portion (153) extending radially at its end. The heat dissipation fan blades (151) are formed on the side surface of the annular connecting portion (153) facing the rear balance block (13), and a plurality of the heat dissipation fan blades (151) are arranged in a circumferential array around the outer wall of the cylindrical connecting portion (152).

3. The rotor assembly according to claim 1, characterized in that, The rotor core (11) has a first shaft hole (111) at its center that is compatible with the rotating shaft (14). The rotor core (11) also has a plurality of locating holes (112) that are axially connected. The plurality of locating holes (112) are arranged in a circular array around the first shaft hole (111). The center of the front balance block (12) is provided with a second shaft hole (122) that is compatible with the rotating shaft (14). On the surface of the front balance block (12) facing the rotor core (11), a first positioning post (123) is provided between any two adjacent first balance holes (121). The total number of the first balance holes (121) and the first positioning post (123) is the same as the number of the positioning holes (112) and they are provided in a one-to-one correspondence. The rear balance block (13) has a third shaft hole (132) at its center that is compatible with the rotating shaft (14). On the surface of the rear balance block (13) facing the rotor core (11), a second positioning post (133) is provided between any two adjacent second balance holes (131). The total number of the second balance holes (131) and the second positioning post (133) is the same as the number of the positioning holes (112) and they are provided in a one-to-one correspondence. The first positioning post (123) is inserted into the positioning hole (112) from the front end face of the rotor core (11) with an interference fit. The second positioning post (133) is inserted into the positioning hole (112) from the rear end face of the rotor core (11) with an interference fit. The positioning hole (112) that is inserted into the first positioning post (123) communicates with the second balance hole (131) on the rear end face of the rotor core (11). The positioning hole (112) that is inserted into the second positioning post (133) communicates with the first balance hole (121) on the front end face of the rotor core (11).

4. The rotor assembly according to claim 3, characterized in that, The rotor core (11) has 6 positioning holes (112), the front balance block (12) has 3 first balance holes (121) and 3 first positioning posts (123), and the rear balance block (13) has 3 second balance holes (131) and 3 second positioning posts (133).

5. The rotor assembly according to claim 3, characterized in that, The front balance block (12) has a plurality of first sector-shaped grooves (124) formed on the surface opposite to the rotor core (11). The plurality of first sector-shaped grooves (124) are arranged in a circular array around the second shaft hole (122). The first balance hole (121) is opened in the first sector-shaped groove (124).

6. The rotor assembly according to claim 3, characterized in that, The rear balance block (13) has a plurality of second sector-shaped grooves (134) formed on the surface opposite to the rotor core (11). The plurality of second sector-shaped grooves (134) are arranged in a circumferential array around the third shaft hole (132). The second balance hole (131) is opened in the second sector-shaped groove (134).

7. The rotor assembly according to claim 3, characterized in that, A magnet (113) is installed in the rotor core (11), and a weight reduction hole (114) is also provided between any two adjacent positioning holes (112).

8. A brushless motor, comprising a housing and a motor body (100) mounted within the housing, characterized in that, The motor body (100) includes a stator assembly (2) and a rotor assembly (1) as described in any one of claims 1-7. The stator assembly (2) is fixedly connected to the housing, and the rotor assembly (1) passes through the stator assembly (2) and rotates in cooperation with the stator assembly (2).

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