Brushless motor and food processor

Abstract

The utility model discloses a brushless motor and a food processor. The brushless motor comprises a front cover, a rotor assembly and a stator assembly. The front cover comprises a containing cavity. The stator assembly and the rotor assembly are both located in the containing cavity. The rotor assembly comprises a motor shaft. The motor shaft penetrates out of the front cover. The front cover includes a bearing mounting portion, and the bearing assembly includes a first bearing and a second bearing. And the first bearing and the second bearing are both assembled on the bearing mounting part and are also assembled with the motor shaft. In the axial direction of the motor shaft, a second bearing is arranged below the first bearing and is spaced from the first bearing, and the height of the second bearing is at least partially overlapped with the height of the rotor assembly. Therefore, the distance between the first bearing and the second bearing in the axial direction of the motor shaft is large, the jumping of the rotor assembly is reduced, and the rotation stability is improved.

Description

Technical Field

[0001] This application relates to the technical field of small household appliances, and particularly to a brushless motor and a cooking machine. Background Art

[0002] A cooking machine includes a brushless motor, a mixing cup, and a knife assembly. The brushless motor includes a rotor assembly and a stator assembly. The rotor assembly includes a motor shaft. The motor shaft is connected to the knife assembly. Under the magnetic field action of the stator assembly and the rotor assembly, the rotor assembly rotates. Furthermore, the motor shaft of the rotor assembly drives the knife assembly to rotate in the mixing cup, so that the ingredients in the mixing cup can be processed.

[0003] However, the existing rotor assembly of the brushless motor has problems of large runout and unstable rotation. Summary of the Utility Model

[0004] The purpose of this application is to disclose a brushless motor and a cooking machine. The brushless motor has small or no runout of the rotor assembly and high rotation stability.

[0005] This application discloses a brushless motor. The brushless motor includes a front cover, a rotor assembly, and a stator assembly. The front cover includes a receiving cavity. The stator assembly and the rotor assembly are located in the receiving cavity. The rotor assembly includes a motor shaft that passes through the front cover. The front cover includes a bearing mounting portion. The bearing assembly includes a first bearing and a second bearing; both the first bearing and the second bearing are assembled in the bearing mounting portion and are also assembled with the motor shaft. And along the axial direction of the motor shaft, the second bearing is located below the first bearing and is spaced from the first bearing, and the height of the second bearing at least partially overlaps with the height of the rotor assembly.

[0006] With the above arrangement, since the brushless motor includes the front cover, the rotor assembly, and the stator assembly, and the stator assembly and the rotor assembly are located in the receiving cavity. Moreover, the rotor assembly is assembled with the bearing mounting portion of the front cover through the first bearing and the second bearing. In this way, since both the first bearing and the second bearing are assembled in the bearing mounting portion, along the axial direction of the motor shaft, the second bearing is located below the first bearing and is spaced from the first bearing, and the height of the second bearing at least partially overlaps with the height of the rotor assembly. Thus, the distance between the first bearing and the second bearing in the axial direction of the motor shaft is large. Furthermore, it is beneficial to reduce the runout of the rotor assembly and improve the rotation stability, so that the rotor assembly has small or no runout and high rotation stability.

[0007] In some embodiments, the stator assembly is fixed to the front cover. The front cover includes a front end of the front cover through which the motor shaft passes. One end of the stator assembly and the rotor assembly opposite to the front end of the front cover is exposed.

[0008] With the above settings, one end of the stator assembly and the rotor assembly opposite to the front cover is exposed, the stator assembly is fixed to the front cover, and the rotor assembly is rotatably connected to the front cover through the first bearing and the second bearing. In this way, no components need to be provided at the end of the brushless motor opposite to the end where the motor shaft passes through (for example, unlike the related art, there is no need to provide a rear motor bracket and a fan blade). The height of the brushless motor along the axial direction of the motor shaft of the rotor assembly is only determined by the height of the front cover and the height of the stator assembly. Therefore, the height of the brushless motor in the axial direction of the motor shaft is low. Secondly, the brushless motor has fewer components and is lighter in weight. Moreover, only the stator assembly, the rotor assembly, and the front cover need to be assembled, with high production efficiency and convenient assembly. Finally, since one end of the stator assembly and the rotor assembly opposite to the front end of the front cover is exposed, the heat dissipation of the stator assembly and the rotor assembly is unobstructed, and the heat dissipation effect is good.

[0009] In some embodiments, the rotor assembly includes a rotor top end and a rotor bottom end. In the height direction of the rotor assembly, the second bearing is located between the rotor top end and the rotor bottom end to be located inside the rotor assembly.

[0010] With the above settings, since the second bearing is located between the rotor top end and the rotor bottom end to be located inside the rotor assembly, in this way, the distance between the first bearing and the second bearing in the axial direction of the motor shaft is greater, which is more conducive to reducing the jump of the rotor assembly and improving the rotational stability, so that the rotor assembly has little or no jump and high rotational stability.

[0011] In some other embodiments, the second bearing protrudes from the rotor bottom end.

[0012] With the above settings, when the second bearing protrudes from the rotor bottom end, the distance between the first bearing and the second bearing in the axial direction of the motor shaft is greater, which is more conducive to reducing the jump of the rotor assembly and improving the rotational stability, so that the rotor assembly has little or no jump and high rotational stability.

[0013] In some embodiments, along the axial direction of the motor shaft, the height between the rotor top end and the rotor bottom end is the height D of the rotor assembly, and the distance between the second bearing and the rotor bottom end is d, and d / D ≤ 0.7.

[0014] With the above settings, the distance between the second bearing and the rotor bottom end is d, and d / D ≤ 0.7. In this way, the distance between the first bearing and the second bearing is greater, which is more conducive to reducing the jump of the rotor assembly and improving the rotational stability, so that the rotor assembly has little or no jump and high rotational stability.

[0015] In some embodiments, the rotor assembly includes a rotor front end plate, a rotor rear end plate, and a rotor core. The rotor core is located between the rotor front end plate and the rotor rear end plate. The rotor front end plate has a bearing seat cavity recessed axially along the motor shaft. The bearing mounting portion includes a second bearing seat extending in a direction opposite to the direction in which the motor shaft passes through. The second bearing seat is located within the accommodation cavity. The second bearing is assembled in the second bearing seat and, as a whole with the second bearing seat, is located within the bearing seat cavity.

[0016] With the above arrangement, by forming the bearing seat cavity by recessing the rotor front end plate axially along the motor shaft, the second bearing is assembled in the second bearing seat and, as a whole with the second bearing seat, is located within the bearing seat cavity. Thus, it is more beneficial to ensure that the axial distance between the first bearing and the second bearing is maximized, and it is more beneficial to reduce the runout of the rotor assembly and improve the rotational stability.

[0017] In some embodiments, the front cover includes a front end of the front cover through which the motor shaft passes. The first bearing is assembled at the front end of the front cover. The front end of the front cover serves as a connection head for connecting the brushless motor to an external structure.

[0018] With the above arrangement, since the front end of the front cover serves as a connection head and the first bearing is assembled at the front end of the front cover, in this way, it can be further ensured that the axial distance between the first bearing and the second bearing can be larger, which is beneficial to reducing the runout of the rotor assembly and improving the rotational stability.

[0019] In some embodiments, the bottom of the bearing seat cavity includes a through hole for the motor shaft to pass through and a rib surrounding the through hole. The rib abuts against the second bearing.

[0020] With the above arrangement, by the rib abutting against the second bearing, it is possible to prevent the rotor assembly from axially moving in the direction in which the motor shaft passes through. In addition, after the rotor assembly is assembled with the motor shaft again (such as through a second fixing member), it can also ensure that the rotor assembly moves axially in the direction in which the motor shaft passes through and in the direction opposite to the passing-through direction. In addition, the rib abutting against the second bearing can make the second bearing seat higher than the bottom of the rotor cavity. In this way, during the rotation of the rotor assembly, there will be no interference with the front cover in the axial direction of the motor shaft. Therefore, there is no need to additionally provide a structure to prevent interference.

[0021] In some embodiments, both the rotor front end plate and the rotor rear end plate are passed through by the motor shaft and rotate synchronously. The rotor core includes a recessed portion recessed axially along the motor shaft. The rotor front end plate includes an insertion post having the bearing seat cavity. The insertion post is located within the recessed portion so that the rotor core is located on the outer periphery of the insertion post. The rotor core is clamped by the rotor front end plate and the rotor rear end plate.

[0022] With the above settings, the rotor core is clamped by the front rotor plate and the rear rotor plate of the rotor. In this way, the assembly between the front rotor plate, the rear rotor plate and the rotor core is convenient. Furthermore, by providing the recessed portion, the weight of the rotor assembly can be reduced, which is beneficial to reducing the moment of inertia of the brushless motor, thereby improving the dynamic response performance of the motor and enabling the motor to accelerate and decelerate more quickly. Finally, the front rotor plate includes a stud having the bearing seat cavity; the stud is located within the recessed portion, which is more conducive to ensuring a large axial distance between the first bearing and the second bearing on the motor shaft, facilitating the reduction of the rotor assembly runout and improving the rotational stability.

[0023] In some embodiments, one of the stud and the recessed portion is provided with a clamping portion, and the front rotor plate and the rotor core are clamped through the clamping portion.

[0024] With the above settings, by providing the clamping portion, a tight fit can be achieved as long as the front rotor plate and the rotor core are pressed tightly. The assembly of the front rotor plate and the rotor core is simple, and the realization of the tight fit is simple.

[0025] In some embodiments, one of the rear rotor plate and the motor shaft is provided with a clamping portion, and the rear rotor plate and the motor shaft are clamped through the clamping portion to achieve the synchronous rotation.

[0026] With the above settings, by providing the clamping portion, a tight fit can be achieved as long as the rear rotor plate and the motor shaft are pressed tightly. The assembly of the rear rotor plate and the motor shaft is simple, and the realization of the tight fit is simple.

[0027] In some embodiments, the rotor assembly includes a recessed portion for reducing the weight of the rotor assembly.

[0028] With the above settings, through the recessed portion, the weight of the rotor assembly can be reduced, which helps to reduce the moment of inertia of the motor, thereby improving the dynamic response performance of the motor and enabling the motor to accelerate and decelerate more quickly.

[0029] In some embodiments, the stator assembly surrounds the rotor assembly, or the rotor assembly surrounds the stator assembly.

[0030] With the above settings, both of the above two methods can achieve a relatively low height of the brushless motor along the axial direction of the motor shaft. In comparison, when the stator assembly surrounds the rotor assembly, the corresponding diameter of the rotor assembly can be relatively small, with a small moment of inertia. Thus, it is not easy to swing during rotation, and the brushless motor operates more smoothly.

[0031] In a second aspect, the present application discloses another brushless motor. The brushless motor includes a front cover, a rotor assembly, a stator assembly, and a bearing assembly. The front cover includes a receiving cavity; the stator assembly is fixed to the front cover, and both the stator assembly and the rotor assembly are located in the receiving cavity, and the rotor assembly includes a motor shaft; the motor shaft passes through the front cover. The front cover includes a bearing mounting portion, and the bearing assembly includes a first bearing and a second bearing; the first bearing is assembled with the motor shaft and the bearing mounting portion, and the second bearing is assembled with the motor shaft and the stator assembly, and the height of the second bearing at least partially overlaps with the height of the rotor assembly.

[0032] As described above, the brushless motor has a low height in the axial direction of the motor shaft, and the distance between the first bearing and the second bearing in the axial direction of the motor shaft is large, which is beneficial to reduce the vibration of the rotor assembly and improve the rotation stability, so that the rotor assembly has small or no vibration and high rotation stability. Furthermore, the brushless motor has few parts and is light in weight. Finally, only the stator assembly, the rotor assembly and the front cover need to be assembled, which has high production efficiency and convenient assembly.

[0033] In a third aspect, the present application discloses a food processor. The food processor comprises any of the aforementioned brushless motors, a blending cup, and a knife assembly, wherein the front cover of the brushless motor comprises a front cover front end for the motor shaft to extend, and the front cover front end is assembled with the bottom of the blending cup. The motor shaft is directly connected to the knife assembly to drive the knife assembly to rotate in the blending cup.

[0034] As described above, since the food processor includes any of the aforementioned brushless motors, the brushless motor has a low axial height on the motor shaft, so the height of the brushless motor accounts for a higher proportion of the cup holder height, which is beneficial to lowering the center of gravity of the cup holder and improving the stability of the blender cup. In addition, it is also beneficial to lower the height of the entire machine, making it easier to store or carry. By assembling the front end of the front cover with the bottom of the blender cup, the brushless motor can be conveniently assembled to the bottom of the blender cup.

[0035] In a fourth aspect, the present application discloses a food processor. The food processor comprises a main machine and a mixing cup assembly, wherein the mixing cup assembly comprises a mixing cup and a knife assembly; the main machine comprises any of the aforementioned brushless motors; the front cover of the brushless motor comprises a front cover front end for the motor shaft to extend, the front cover front end is assembled with the main machine, and the brushless motor drives the knife assembly to rotate in the mixing cup.

[0036] With the above settings, since the cooking machine includes any of the aforementioned brushless motors, and the axial height of the brushless motor on the motor shaft is low, the proportion of the height of the brushless motor in the height of the main body is increased, which is beneficial to reducing the center of gravity of the main body and improving the stability of the main body. In addition, the main body is thinner and lighter. Furthermore, by assembling the front end of the front cover with the main body, the brushless motor can be conveniently assembled to the main body. Description of the Drawings

[0037] Figure 1 is a perspective view of a brushless motor shown according to an embodiment of the present application. The brushless motor includes a first front cover;

[0038] Figure 2 is Figure 1 an exploded view of the brushless motor shown;

[0039] Figure 3 is Figure 1 a cross-sectional view of the brushless motor shown;

[0040] Figure 4 is Figure 3 a schematic diagram of the assembly of the front cover and the bearing assembly of the brushless motor shown;

[0041] Figure 5 is a cross-sectional view of the rotor assembly of the brushless motor shown according to an embodiment of the present application;

[0042] Figure 6 is a schematic diagram of the front end plate of the rotor of the brushless motor shown according to an embodiment of the present application;

[0043] Figure 7 is a schematic diagram of the motor shaft of the brushless motor shown according to an embodiment of the present application;

[0044] Figure 8 is a cross-sectional view of the second front cover of the brushless motor shown according to an embodiment of the present application;

[0045] Figure 9 is a schematic diagram of the assembly of the rotor assembly of the brushless motor, Figure 8 the front cover shown, and the bearing assembly together;

[0046] Figure 10 is a schematic diagram of the third front cover shown according to an embodiment of the present application;

[0047] Figure 11 is a cross-sectional view of the first cooking machine of the present application. The first cooking machine includes the brushless motor;

[0048] Figure 12 is a cross-sectional view of the second cooking machine of the present application. The second cooking machine includes the brushless motor;

[0049] Figure 13 In the related art, it is an exploded view of a brushless motor;

[0050] Figure 14 In the related art, it is a cross-sectional view of a first food processor, and the first food processor includes Figure 13 the brushless motor shown;

[0051] Figure 15 In the related art, it is a cross-sectional view of a second food processor, and the second food processor includes Figure 13 the brushless motor shown. Specific embodiments

[0052] Here, the technical solutions in the embodiments (or "embodiment modes") of the present application will be clearly and completely described in conjunction with the accompanying drawings. When the following description involves the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements.

[0053] If there are terms related to directional indications or positional relationships in the embodiments of the present application (such as up, down, left, right, front, back, inside, outside, top, bottom, center, vertical, horizontal, longitudinal, transverse, length, width, counterclockwise, clockwise, axial, radial, circumferential, etc.), such terms are only used to explain the relative positional relationships and movement conditions between components in a specific posture (as shown in the accompanying drawings); if the specific posture changes, then the directional indication or positional relationship also changes accordingly. In addition, the terms "first", "second", etc. involved in the embodiments of the present application are only for the purpose of convenient description and cannot be understood as indicating or implying relative importance.

[0054] See Figure 3 and in conjunction with Figure 1 , Figure 2 and Figure 9 , the present application discloses a brushless motor 10. The brushless motor 10 includes a front cover 1, a rotor assembly 2, and a stator assembly 3. The front cover 1 includes a receiving cavity 11. The stator assembly 3 and the rotor assembly 2 are both located in the receiving cavity 11, and the rotor assembly 2 includes a motor shaft 21. The motor shaft 21 passes through the front cover 1. For example, the front cover 1 includes a front end 14 of the front cover, and the motor shaft 21 passes through the front end 14 of the front cover.

[0055] See Figure 2 , Figure 3 , Figure 4 , Figure 8 and Figure 9 , the front cover 1 includes a bearing mounting portion 150. The bearing assembly 4 includes a first bearing 41 and a second bearing 42. The following describes some assembly methods of the first bearing 41 and the second bearing 42:

[0056] See Figure 3 and Figure 4 As shown, the front cover 1 includes a bearing receiving cavity 12. The inner wall of the bearing receiving cavity 12 forms an upper step and a lower step. The bearing assembly 4 includes a first bearing 41, a second bearing 42, and a bearing circlip 44. The second bearing 42 is located on the lower step and is clamped by the circlip 44. The first bearing 41 is located on the upper step and is clamped by a first fixing member (such as a circlip) of the rotor assembly 2.

[0057] See Figure 8 and Figure 9 In some other embodiments, as shown, a rib 2191 is provided at the bottom of the bearing receiving cavity 12. The bearing assembly 4 includes a first bearing 41, a second bearing 42, and a bearing retaining sleeve 43. The second bearing 42 is located between the bottom end of the bearing retaining sleeve 43 and the rib 2191. The first bearing 41 is located at the top end of the bearing retaining sleeve 43 and is clamped by a first fixing member 23 (such as a circlip) of the rotor assembly 2.

[0058] In this embodiment, it is shown that the first bearing 41 and the second bearing 42 are each one, but the number is not limited thereto. Regardless of the assembly method, the first bearing 41 and the second bearing 42 are both assembled in the bearing mounting portion 150 and are also assembled with the motor shaft 21. Along the axial direction of the motor shaft 21, the second bearing 42 is located below the first bearing 41 and is spaced from the first bearing 41. The height of the second bearing 42 at least partially overlaps with the height of the rotor assembly 2. The rotor assembly 2 includes a rotor top end 2100 (see L1 in Figure 3 ) and a rotor bottom end 2101 (see L2 in Figure 3 ). Based on this, the at least partial overlap includes the following three cases: 1) The second bearing 42 protrudes from the rotor top end 2100; 2) As described later, the second bearing 42 is located between the rotor top end 2100 and the rotor bottom end 2101; 3) The second bearing 42 protrudes from the rotor bottom end 2101.

[0059] As described above, since the brushless motor 10 includes the front cover 1, the rotor assembly 2 and the stator assembly 3, the stator assembly 3 and the rotor assembly 2 are located in the accommodating chamber 11, and the rotor assembly 2 is assembled with the bearing mounting portion 150 of the front cover 1 through the first bearing 41 and the second bearing 42 to realize rotational connection with the front cover 1. In this case, since the first bearing 41 and the second bearing 42 are both assembled in the bearing mounting portion 150, the second bearing 42 is located below the first bearing 41 and is spaced from the first bearing 41 in the axial direction of the motor shaft 21, and the height of the second bearing 42 at least partially overlaps with the height of the rotor assembly 2, so that the distance between the first bearing 41 and the second bearing 42 in the axial direction of the motor shaft 21 is large, which is conducive to reducing the vibration of the rotor assembly and improving the rotation stability, so that the rotor assembly 2 has small or no vibration and high rotation stability.

[0060] In some embodiments, see Figure 3 and Figure 1 , the stator assembly 3 is fixed to the rotor assembly 2. There is no limit to how to fix them. For example, the stator core 31 of the stator assembly 3 is interference fit with the front cover 1, or the front cover rear end 13 of the front cover 1 is provided with a limiting portion 131, and the limiting portion 131 is bent and located in the radial direction of the motor shaft 21 and abuts against the stator assembly 3. The interference fit and the limiting portion 131 are combined to achieve the fixation of the front cover 1 and the stator assembly 3. In addition, the stator assembly 3 and the front cover 1 can also be limited by an axial limiting mechanism 33, or a limiting groove 342 is provided on the side wall of the accommodating cavity 11 of the front cover 1, and a limiting protrusion is provided on the stator assembly 3, and the limiting protrusion is located in the limiting groove 342 to prevent the positioning assembly 3 and the front cover 1 from rotating relative to each other. In short, no matter which setting is used, as long as the stator assembly 3 and the front cover 1 do not move relative to each other during the operation of the brushless motor, it is sufficient. The stator assembly 3 and the rotor assembly 2 are both located in the accommodating cavity 11. The rotor assembly 2 includes a motor shaft 21. The motor shaft 21 passes through the front cover 1. There is no limit to how the motor shaft 21 passes through the front cover 1. The stator assembly 3 and the rotor assembly 2 are exposed at the end opposite to the front cover 1 (i.e., the end opposite to the motor shaft 21 passing through the front cover 1, for example, the front cover front end 14 described later). In some embodiments, see Figure 3 , the stator assembly 3 and the rotor assembly 2 are located behind the accommodating cavity 11 , and the stator assembly 3 and the rotor assembly 2 are exposed from the opening of the accommodating cavity 11 . Figure 3It is shown that the exposed distance is a. However, based on the beneficial effects that the stator assembly 3 and the rotor assembly 2 described later are exposed for heat dissipation and the rear motor bracket 92 does not need to be provided, the exposure also includes the case where a ≤ 0 (that is, the end face of the stator assembly 3 is flush with the opening of the accommodation cavity 11, or even the stator assembly 3 is located within the accommodation cavity 11). In short, as long as the stator assembly 3 and the rotor assembly 2 can be exposed to the outside through the accommodation cavity 11 for heat dissipation and the rear motor bracket 92 etc. do not need to be provided.

[0061] With the above settings, since the brushless motor 10 includes the front cover 1, the rotor assembly 2 and the stator assembly 3, the stator assembly 3 is fixed to the front cover 1 and is located within the accommodation cavity 11 together with the rotor assembly 2. Moreover, the rotor assembly 2 is assembled with the bearing mounting portion 150 of the front cover 1 through the first bearing 41 and the second bearing 42 to achieve the rotatable connection between the rotor assembly 2 and the front cover 1. Thus, no components (such as the rear motor bracket 92 and the fan blade) need to be provided at the end of the brushless motor 10 opposite to the end where the motor shaft passes through. The height of the brushless motor 10 is determined by the height of the front cover 1 and the height of the stator assembly 3. For example, in the case where the stator assembly 3 and the rotor assembly 2 as shown are partially located within the accommodation cavity 11 of the front cover 1, the height h1 of the brushless motor 10 along the axial direction of the motor shaft 21 of the rotor assembly 2 is h1 = a + b, where a is the height of the stator assembly 3 exposed outside the brushless motor 10, and b is the height of the front cover. As for Figure 3 the height c and d in, c in Figure 2 is mainly the height by which the rotor rear end plate 222 of the rotor assembly 2 protrudes. On the one hand, this part of the height c can be adjusted. For example, it can be made flush with the stator assembly 3 or there is no c as shown in Figure 3 . On the other hand, the stator assembly 3 and the rotor need to satisfy the positional relationship to enable the rotation of the rotor assembly 2. Therefore, the rotor assembly 2 cannot protrude too much, and c will not be too large. Thus, due to the above two reasons, the influence of the height c does not need to be considered; for the height d, this part is used as a connector to connect the clutch, and the height of the connector can be adjusted. Therefore, when determining the height of the brushless motor, this part of the height d is not considered; for another example, in the case where the stator assembly 3 is completely located within the accommodation cavity 11 of the front cover 1, the height of the brushless motor 10 is equal to the height of the front cover 1. In summary, the height of the brushless motor 10 is low. For example, compared with Figure 2 the related art shown, it is not determined by the respective heights of the front motor bracket 91, the rotor assembly 2, the stator assembly 3, the rear motor bracket 92 and the fan blade 93. Figure 13

[0062] Secondly, only considering the number of components, the brushless motor has fewer components. For example, compared with Figure 13 ​Compared with the related art described above, since the stator assembly 3 is fixed to the front cover 1, and the stator assembly 3 and the rotor assembly 2 are exposed at one end opposite to the end where the motor shaft 21 passes through the front cover 1, there is no longer a need for the rear motor bracket 92 and the front motor bracket 91 to clamp the stator assembly 3 with screws 94. Therefore, considering the connection of the stator assembly 3 to that component, at least the rear motor bracket 92 can be omitted. The brushless motor 10 is light in weight and low in axial height.

[0063] Furthermore, the stator assembly 3 and the rotor assembly 2 are exposed at one end opposite to the end where the motor shaft 21 passes through the front cover, and there is no obstruction to the heat dissipation of the stator assembly 3 and the rotor assembly 2 (such as the stator winding). On the one hand, the heat dissipation effect is good. On the other hand, the fan blade can be omitted, making the structure of the brushless motor simple. Omitting the fan blade can make the axial height of the brushless motor low. For example, compared with Figure 13 the brushless motor shown, the fan blade 93 can be omitted while ensuring good heat dissipation. In addition, in this application, the stator assembly 3 and the rotor assembly 2 are partially located in the accommodation cavity 11 and exposed outside the front cover 1. Compared with the case where the stator assembly 3 and the rotor assembly 2 are all located in the accommodation cavity 11 of the front cover 1 and exposed, at least the depth of the accommodation cavity 11 is shallower and materials can be omitted, the brushless motor 10 is lighter in weight, and the exposed part is more and the heat dissipation effect is better.

[0064] Finally, it is necessary to assemble the stator assembly 3, the rotor assembly 2 and the front cover 1, with high production efficiency and convenient assembly. For example, compared with Figure 13 the related art shown, since at least the step of assembling the rear motor bracket 92 can be omitted (in some embodiments, since the fan blade 93 is not needed, the step of assembling the fan blade 93 can also be omitted), the production efficiency is high and the assembly is convenient.

[0065] Although the foregoing embodiments illustrate that the rotor assembly 2 is rotatably connected to the front cover 1, however, inspired by the movement of the rotor assembly 2 and the stillness of the front cover 1, and in addition, there is no relative movement between the stator assembly 3 and the front cover 1. Therefore, in some embodiments, it is also possible that the rotor assembly 2 is rotatably connected to both the front cover 1 and the stator assembly 3. Specifically, such a brushless motor is as follows: The brushless motor includes a front cover 1, a rotor assembly 2, a stator assembly 3 and a bearing assembly 4, wherein: The front cover 1 includes an accommodation cavity 11. The stator assembly 3 is fixed to the front cover 1 and is located in the accommodation cavity 11 together with the rotor assembly 2; The rotor assembly 2 includes a motor shaft 21. The motor shaft 21 passes through the front cover 1. The front cover 1 includes a bearing mounting portion 150, and the bearing assembly 4 includes a first bearing 41 and a second bearing 42; The first bearing 41 is assembled with the motor shaft 21 and the bearing mounting portion 150, and the second bearing 42 is assembled with the motor shaft 21 and the stator assembly 3, and the height of the second bearing 42 at least partially overlaps with the height of the rotor assembly 2.

[0066] In the above setting, in this embodiment, since the rotor assembly 2 is connected to the bearing mounting portion 150 through the second bearing 42, it is changed to that the rotor assembly 2 is rotatably connected to the stator assembly 3 through the second bearing 42, and the other connection relationships are still the same as those in the foregoing embodiment. Therefore, it still has the beneficial effects of the foregoing embodiment and will not be elaborated herein.

[0067] See Figure 3 , Figure 5 and Figure 9 , in some embodiments, the rotor assembly 2 includes a rotor top end 2100 and a rotor bottom end 2101. In the height direction of the rotor assembly 2, the second bearing 42 is located between the rotor top end 2100 and the rotor bottom end 2101 so as to be located inside the rotor assembly 2. Referring to Figure 3 the dashed lines L1 and L2 shown, the second bearing 42 is located between L1 and L2 and thus inside the rotor assembly 2. The second bearing 42 being located inside the rotor assembly 2 is not limited to the above embodiment.

[0068] In the above setting, since the second bearing 42 is located between the rotor top end 2100 and the rotor bottom end 2101 so as to be located inside the rotor assembly 2, in this way, the distance between the first bearing 41 and the second bearing 42 in the axial direction of the motor shaft 21 is greater, which is more beneficial to reducing the jump of the rotor assembly 2 and improving the rotational stability, so that the rotor assembly 2 has little or no jump and high rotational stability.

[0069] As a variation of the above embodiment, in some other embodiments, the second bearing 42 protrudes from the rotor bottom end 2101, that is, in Figure 2 the drawing direction shown, the second bearing 42 is lower than the dashed line L2.

[0070] In the above setting, when the second bearing 42 protrudes from the rotor bottom end 2101, the distance between the first bearing 41 and the second bearing 42 in the axial direction of the motor shaft 21 is greater, which is more beneficial to reducing the jump of the rotor assembly 2 and improving the rotational stability, so that the rotor assembly 2 has little or no jump and high rotational stability.

[0071] Continue to refer to Figure 3 and Figure 5, along the axial direction of the motor shaft 21, the height between the top end 2100 and the bottom end 2101 of the rotor is the height D of the rotor assembly 2, and the distance between the second bearing 42 and the bottom end 2101 of the rotor is d, where d / D ≤ 0.7. For example, 0.7, 0.65, 0.6, 0.55, 0.52, 0.52, 0.5, 0.48, 0.45, 0.43, 0.4, 0.38, 0.35, 0.32, 0.3 or 0.25, etc.

[0072] With the above arrangement, the distance between the second bearing 42 and the bottom end 2101 of the rotor is d, where d / D ≤ 0.7. In this way, the distance between the first bearing 41 and the second bearing 42 is greater, which is more conducive to reducing the pulsation of the rotor assembly 2 and improving the rotational stability, so that the rotor assembly 2 has little or no pulsation and high rotational stability.

[0073] See Figure 3 , Figure 4 and Figure 9 , the front cover 1 includes a front end 14 of the front cover through which the motor shaft 21 passes, and the first bearing 41 is assembled to the front end 14 of the front cover.

[0074] With the above arrangement, the first bearing 41 is assembled to the front end 14 of the front cover. In this way, the axial distance between the first bearing 41 and the second bearing 42 on the motor shaft 21 can be greater, which is conducive to reducing the pulsation of the rotor assembly and improving the rotational stability.

[0075] In some embodiments, see Figure 3 and in combination with Figure 11 and Figure 12 , the front end 14 of the front cover serves as a connector for connecting the brushless motor to an external structure. How the connector is connected to the external structure can be seen in the description of the subsequent food processor part.

[0076] With the above arrangement, since the front end 14 of the front cover serves as a connector and the first bearing 41 is assembled to the front end 14 of the front cover, in this way, it can be further ensured that the axial distance between the first bearing 41 and the second bearing 42 on the motor shaft 21 can be greater, which is conducive to reducing the pulsation of the rotor assembly and improving the rotational stability.

[0077] See Figure Figure 2 , Figure 5 and Figure 9 , the rotor assembly 2 includes a motor shaft 21 and a rotor body 22. The rotor body 22 includes a rotor front end plate 221, a rotor rear end plate 222, a rotor iron core 223, and magnetic sheets 224 assembled to the rotor iron core 223. The rotor iron core 223 is located between the rotor front end plate 221 and the rotor rear end plate 222. The rotor front end plate 221 is recessed with a bearing seat cavity 2211 in the axial direction of the motor shaft 21, as Figure 5As shown, the front end plate 221 of the rotor is recessed in the direction of arrow R1 to form a bearing seat cavity 2211. The bearing mounting portion 150 includes a second bearing seat 15 extending in a direction opposite to the direction in which the motor shaft 21 passes through. The second bearing seat 15 is located within the accommodation cavity 11. The second bearing 42 is assembled in the second bearing seat 15 and, as a whole with the second bearing seat 15, is located within the bearing seat cavity 2211.

[0078] With the above arrangement, by recessing the front end plate 221 of the rotor axially along the motor shaft 21 to form the bearing seat cavity 2211, and assembling the second bearing 42 in the second bearing seat 15 and locating them as a whole within the bearing seat cavity 2211, it is more conducive to ensuring that the axial distance between the first bearing 41 and the second bearing 42 is maximized, more conducive to reducing the runout of the rotor assembly, and improving the rotational stability.

[0079] See Figure 3 、 Figure 5 and Figure 9 As shown, the bottom of the bearing seat cavity 2211 includes a through hole for the motor shaft 21 to pass through and ribs 2212 surrounding the through hole. The ribs 2212 abut against the second bearing 42.

[0080] With the above arrangement, by abutting the ribs 2212 against the second bearing 42, it is possible to prevent the rotor assembly 2 from axially moving in the direction in which the motor shaft 21 passes through. In addition, when the rotor assembly 2 is reassembled with the motor shaft 21 (such as through the second fixing member 24), it can also ensure that the rotor assembly 2 moves axially in the direction in which the motor shaft 21 passes through and in the direction opposite to the passing-through direction. In addition, the abutment of the ribs 2212 against the second bearing 42 can make the second bearing seat 15 higher than the bottom of the rotor cavity 2211. In this way, during the rotation of the rotor assembly 2, there will be no interference with the front cover 1 in the axial direction of the motor shaft 21. Therefore, there is no need to additionally provide a structure to prevent interference.

[0081] In some embodiments, the outer diameter of the second bearing seat 15 is smaller than the inner diameter of the rotor cavity 2211. As shown in Figure 3 , the distance difference between the two is d.

[0082] With the above arrangement, the outer diameter of the second bearing seat 15 is smaller than the inner diameter of the rotor cavity 2211. In this way, during the rotation of the rotor assembly 2, there will be no interference with the front cover 1 in the radial direction of the motor shaft 21. This embodiment, combined with the abutment of the ribs 2212 against the second bearing 42, can achieve interference between the rotor assembly 2 and the front cover 1 in both the radial and axial directions of the motor shaft 21.

[0083] See Figure 3 、 Figure 5 and Figure 9, in some embodiments, both the front rotor plate 221 and the rear rotor plate 222 are penetrated by the motor shaft 21 and rotate synchronously. There is no limitation on how to achieve synchronous rotation. For example, synchronous rotation can be achieved by setting an anti-rotation structure, and the specific structure of the anti-rotation structure is not limited as long as synchronous rotation can be achieved. The rotor core 223 includes a recessed portion 2231 that is recessed along the axial direction of the motor shaft 21. In Figure 2 , the recessed portion 2231 penetrates the rotor core. In some embodiments, the recessed portion 2231 may not penetrate the rotor core 223 either. Refer to Figure 6 , the front rotor plate 221 includes a stud 2213 having the bearing seat cavity 2211. Refer to Figure 5 and Figure 3 , the stud 2213 is located in the recessed portion 2231 so that the rotor core 223 is located on the outer periphery of the stud 2213. The rotor core 223 is clamped by the front rotor plate 221 and the rear rotor plate 222.

[0084] With the above settings, the rotor core 223 is clamped by the front rotor plate 221 and the rear rotor plate 222. In this way, the assembly between the front rotor plate 221, the rear rotor plate 222 and the rotor core 223 is convenient. Furthermore, by providing the recessed portion 2231, the weight of the rotor assembly 2 can be reduced, which is beneficial to reducing the moment of inertia of the brushless motor, thereby improving the dynamic response performance of the motor and enabling the motor to accelerate and decelerate more quickly. Finally, the front rotor plate 221 includes a stud 2213 having the bearing seat cavity 2211; the stud 2213 is located in the recessed portion 2231, which is more beneficial to ensuring a large axial distance between the first bearing 41 and the second bearing 42 on the motor shaft, facilitating reducing the jump of the rotor assembly and improving the rotational stability.

[0085] Refer to Figure 6 , the stud 2213 is provided with a clamping portion 2214 (due to subsequent functions, the clamping portion 2214 is, for example, the anti-rotation rib). The clamping portion 2214 is distributed circumferentially along the stud 2213 in Figure 6 , but is not limited thereto. The front rotor plate 221 and the rotor core 223 are clamped by the clamping portion 2214 to achieve the tight fit. That is, during the pressing process between the front rotor plate 221 and the rotor core 223, the clamping portion 2214 will be clamped (such as interference) between the stud 2213 and the recessed portion 2231, thereby achieving the tight fit. Based on the role played by the clamping portion 2214, as long as at least one of the recessed portion 2231 and the stud 2213 is provided with the clamping portion 2214. The clamping portion 2214 has an interference fit with the other of the stud 2213 and the rotor core 223 to achieve the tight fit.

[0086] With the above settings, by providing the clamping portion 2214, as long as the front rotor plate 221 and the rotor core 223 are pressed together, the clamping portion 2214 is clamped between the insertion post 2213 and the recess 2231, and a tight fit (and anti-rotation) can be achieved. The assembly of the front rotor plate 221 and the rotor core 223 is simple, and achieving a tight fit is simple.

[0087] See Figure 7 , the motor shaft 21 is provided with a clamping portion 211 (the clamping portion 211 is, for example, an anti-rotation rib). The rear rotor plate 222 and the motor shaft 21 are clamped through the clamping portion 211 to achieve synchronous rotation. Based on the function of the clamping portion 211, as long as at least one of the motor shaft 21 and the rear rotor plate 222 is provided with the clamping portion 211, and the clamping portion 211 has an interference fit with the other of the motor shaft 21 and the rear rotor plate 222.

[0088] With the above settings, by providing the clamping portion 211, as long as the rear rotor plate 222 and the motor shaft 21 are pressed together, a tight fit can be achieved. The assembly of the rear rotor plate 222 and the motor shaft 21 is simple, and achieving a tight fit is simple.

[0089] In the foregoing embodiment, the recess 2231 of the rotor core 223 functions to reduce the weight of the rotor assembly 2. Considering only this function, the recess 2231 may not extend along the axial direction of the motor shaft 21. That is, the rotor assembly 2 includes a recess 2231 for reducing the weight of the rotor assembly 2. Further, the recess 2231 is not limited to being provided in the rotor core 223. In some cases, it also includes recesses in at least one of the front rotor plate 221 and the rear rotor plate 222. The recess 2231 is not limited to holes or the like, as long as the weight can be reduced.

[0090] With the above settings, through the recess 2231, the weight of the rotor assembly 2 can be reduced, which helps to reduce the moment of inertia of the motor, thereby improving the dynamic response performance of the motor and enabling the motor to accelerate and decelerate more quickly.

[0091] See Figure 3 , Figure 3 In the brushless motor 10 shown, the stator assembly 3 surrounds the rotor assembly 2. As a variation of this embodiment, it is also possible that the rotor assembly 2 surrounds the stator assembly 3. Regardless of which design, since the stator assembly 3 does not move during motor operation, in both embodiments, the stator assembly 3 is fixed to the front cover 1.

[0092] With the above settings, both of the above two methods can achieve a relatively low height of the brushless motor 10 along the axial direction of the motor shaft. Comparing the two, when the stator assembly 3 surrounds the rotor assembly 2, the corresponding diameter of the rotor assembly 2 can be relatively small, and the moment of inertia is small. Thus, during rotation, it is not easy to swing, and the brushless motor 10 operates more smoothly.

[0093] Some other features of the brushless motor are described as follows:

[0094] See Figure 3 , the stator assembly 3 includes a stator core 31 and a stator winding 32 assembled on the stator core 31. In this application, the stator winding 32 includes a coil winding 321 and a stator bracket 322. The coil winding 321 is wound around the stator bracket 322. See Figure 4 and Figure 8 , an axial limiting mechanism 33 is provided between the stator core 31 and the wall of the accommodating cavity 11, and the axial limiting mechanism 33 limits the stator assembly 3 axially along the motor shaft 21. A circumferential limiting mechanism 34 (the circumferential limiting mechanism is not limited, for example, including Figure 10 the limiting groove 342 shown in Figure 1 and

[0095] the limiting protrusion 341 shown in

[0096] Figure 1 Figure 10 Figure 1

[0097]

[0098] Figure 1 Figure 10 As described above, the circumferential limiting mechanism 34 includes the limiting protrusion 341 and the limiting groove 342, the structure of the circumferential limiting mechanism 34 is simple, the assembly between the stator assembly 3 and the front cover 1 is also simple and convenient, and the production efficiency is high.

[0098] Continue to refer to Figure 1 and Figure 10, the limiting groove 342 and the limiting protrusion 341 both extend along the axial direction of the motor shaft 21, and the limiting groove 342 is a notch formed on the cavity wall.

[0099] With the above arrangement, since both the limiting groove 342 and the limiting protrusion 341 extend along the axial direction of the motor shaft 21, and the limiting groove 342 is a notch, along the axial direction, inserting the stator assembly 3 into the receiving cavity 11 can make the limiting protrusion 341 located in the limiting groove 342 to achieve circumferential limitation. Thus, not only the positioning function is realized, but also the assembly of the stator assembly 3 is convenient, simple, and the production efficiency is high.

[0100] See Figure 4 and Figure 8 , the axial limiting mechanism 33 is a step provided on the cavity wall. The stator core 31 abuts against the step to achieve the axial limitation.

[0101] With the above arrangement, since the axial limiting mechanism 33 is a step and the stator core 31 abuts against the step, in this way, the realization of the axial positioning is simple, and correspondingly, the structure of the front cover 1 is also simple. In addition, after inserting the stator assembly 3 into the receiving cavity 11, the stator core 31 can abut against the step, and the assembly of the stator assembly 3 and the front cover 1 is simple and the production efficiency is high.

[0102] In some embodiments, the stator core 31 is in interference fit with the cavity wall of the receiving cavity 11.

[0103] With the above arrangement, through the interference fit, the loosening of the stator assembly 3 is avoided, for example, falling out of the receiving cavity 11. Moreover, through the interference fit, the assembly of the stator assembly 3 and the front cover 1 is also simple and the production efficiency is high. For example, Figure 13 As shown in the brushless motor, screws 94 need to pass through the rear motor bracket 92, the installation groove 310 of the stator assembly 3 and the front motor bracket 91 to lock the stator assembly 3 between the front motor bracket 91 and the rear motor bracket 92. The assembly between the stator assembly 3 and the front cover 1 in the present application and Figure 13 Compared with the assembly method shown, it does not require the screws 94 to be locked. Therefore, the assembly is simple, convenient, and the production efficiency is high.

[0104] See Figure 10, the front cover 1 includes a rear end 13 of the front cover. The rear end 13 of the front cover includes a limiting portion 131 extending toward the inner side of the front cover 1. The limiting portions 131 are circumferentially distributed on the front cover 1. During assembly, the limiting portion 131 is bent to the radial direction of the motor shaft 21 so that the limiting portion 131 abuts against the stator assembly 3 to limit the axial movement of the stator assembly 3 on the motor shaft 21 of the rotor assembly 2. Based on the function achieved by the connection between the limiting portion 131 and the stator assembly 3, the connection method is not limited. For example, as shown in the present application, the limiting portion 131 extends along the axial direction of the motor shaft 21, and the limiting portion 131 is bent from the axial direction to the radial direction by pressing to abut against the stator assembly 3. In some other embodiments, the connection can also be a fixed connection such as welding. In short, no matter which connection method is used, as long as the stator assembly 3 does not fall off and does not move axially on the motor shaft 21.

[0105] With the above arrangement, by restricting the axial movement of the stator assembly 3 by the limiting portion 131, it is possible to prevent the stator assembly 3 from falling out and also prevent the stator assembly 3 from loosening axially on the motor shaft 21. In addition, the stator assembly 3 can be assembled with the front cover 1 through the limiting portion 131, which also makes the assembly of the stator assembly 3 and the front cover 1 simple, convenient and highly efficient. For example, only the limiting portion 131 needs to be bent, instead of Figure 13 the brushless motor 10 shown, where screws 94 need to pass through the rear motor bracket 92, the mounting groove 310 of the stator assembly 3 and the front motor bracket 91 to lock the stator assembly 3 between the front motor bracket 91 and the rear motor bracket 92. The locking of the screws 94 makes the assembly troublesome, inconvenient and inefficient.

[0106] In some embodiments, the limiting portion 131 can replace the interference fit between the stator assembly 3 and the cavity wall of the receiving cavity 11. However, in some other embodiments, the stator assembly 3 not only has an interference fit with the cavity wall of the receiving cavity 11 of the front cover 1 but is also limited by the limiting portion 131. In addition, the limiting portion 131 can also be combined with the step. That is, the front end of the stator core of the stator assembly 3 abuts against the step, and the rear end (the exposed end) is limited by the limiting portion 131. Thus, the stator assembly 3 is further limited by the combination of the step and the limiting portion.

[0107] See Figure 11, this application discloses a cooking machine. The cooking machine includes any of the above brushless motors 10, a mixing cup 20, and a knife assembly 30. The front cover 1 of the brushless motor 10 includes a front end 14 of the front cover for the motor shaft 21 to extend out, and the front end 14 of the front cover is assembled with the bottom of the mixing cup 20. For example, it is assembled by threads or snap-fits. The motor shaft 21 of the brushless motor 10 is directly connected to the knife assembly 30 to drive the knife assembly 30 to rotate in the mixing cup 20. That is, Figure 11 The shown cooking machine is a direct-drive cooking machine.

[0108] With the above settings, since the cooking machine includes any of the above brushless motors 10, because the axial height of the brushless motor 10 on the motor shaft 21 is low, in this way, the proportion of the height h1 of the brushless motor 10 in the height h2 of the cup holder is increased, which is beneficial to reducing the center of gravity of the cup holder and improving the stability of the mixing cup 20. In addition, it is also beneficial to reduce the height of the whole machine, which is convenient for storage or carrying. More specifically, in Figure 14 , the height h1 of the brushless motor and the height h2 of the cup holder satisfy: h1 / h2 = 0.69. For example, h1 = 45 mm and h2 = 65 mm. After adopting the brushless motor 10 of this application, as Figure 11 shown, the height h1 of the brushless motor = 36 mm, the height h2 of the cup holder = 49 mm, h1 / h2 = 0.73. The ratio h1 / h2 of the height of the brushless motor 10 to the height of the cup holder is increased from 0.69 to 0.73, and the proportion of the height of the brushless motor 10 in the height of the cup holder is increased, which is beneficial to reducing the center of gravity of the cup holder and improving the stability of the mixing cup 20. In addition, through the assembly of the front end 14 of the front cover with the bottom of the mixing cup 20, the brushless motor can be conveniently assembled at the bottom of the mixing cup.

[0109] See Figure 11 , this application also discloses another cooking machine. The mixing cup assembly and the main body of this cooking machine are split. Specifically, the cooking machine includes a main body 100 and a mixing cup assembly 200. The mixing cup assembly 200 includes a mixing cup 20 and a knife assembly 30. The main body 100 includes any of the above brushless motors 10. The front cover 1 of the brushless motor includes a front end 14 of the front cover for the motor shaft 21 to extend out, and the front end 14 of the front cover is with the main body 100. When the mixing cup assembly 200 is assembled on the main body 100, the brushless motor 10 drives the knife assembly 30 to rotate in the mixing cup 20.

[0110] With the above settings, since the cooking machine includes any one of the aforementioned brushless motors 10, and because the axial height of the brushless motor 10 on the motor shaft 21 is low, in this way, the proportion of the height h1 of the brushless motor 10 in the height h3 of the main body is increased, which is beneficial to reducing the center of gravity of the main body 100 and improving the stability of the main body 100. In addition, the main body 100 is thinner and lighter. More specifically, in Figure 15 , the height h1 of the brushless motor and the height h3 of the main body satisfy: h1 / h3 = 0.49. For example, the height h1 of the brushless motor 10 = 45 mm; the height h3 of the main body = 92 mm. After adopting the brushless motor 10 of the present application, as Figure 12 shown, the height h1 of the brushless motor 10 = 36 mm, and the height h3 of the main body = 64 mm. Therefore, the ratio h1 / h3 of the height h1 of the brushless motor 10 to the height h3 of the main body 100 is increased from 0.49 to 0.56 (the recommended range is 0.5 - 1.0, preferably 0.56), thereby improving the stability of the main body 100. The height of the brushless motor 10 is reduced by 9 mm, the overall height of the machine is reduced by 28 mm, and the main body 100 is thinner and lighter. Furthermore, by assembling the front end 14 of the front cover with the main body 100, the brushless motor can be conveniently assembled to the main body.

[0111] It should be noted that the technical solutions or technical features described in the above embodiments can be combined or supplemented with each other without conflict. The scope of protection of the present application is not limited to the precise structures described in the above embodiments and shown in the drawings; any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the scope of protection of the present application.

Claims

1. A brushless motor, characterized in that, The brushless motor includes a front cover (1), a rotor assembly (2), a stator assembly (3), and a bearing assembly (4), where: The front cover (1) includes a receiving cavity (11); The stator assembly (3) and the rotor assembly (2) are both located in the receiving cavity (11). The rotor assembly (2) includes a motor shaft (21); the motor shaft (21) passes through the front cover (1); The front cover (1) includes a bearing mounting portion (150). The bearing assembly (4) includes a first bearing (41) and a second bearing (42); both the first bearing (41) and the second bearing (42) are assembled in the bearing mounting portion and are also assembled with the motor shaft (21). Along the axial direction of the motor shaft (21), the second bearing (42) is located below the first bearing (41) and is spaced from the first bearing (41), and the height of the second bearing (42) at least partially overlaps with the height of the rotor assembly (2).

2. The brushless motor according to claim 1, wherein, The stator assembly (3) is fixed to the front cover (1). The front cover (1) includes a front end (14) of the front cover through which the motor shaft (21) passes. One end of the stator assembly (3) and the rotor assembly (2) opposite to the front end (14) of the front cover is exposed.

3. The brushless motor according to claim 1, wherein The rotor assembly (2) includes a rotor top end (2100) and a rotor bottom end (2101); in the height direction of the rotor assembly (2), the second bearing (42) is located between the rotor top end (2100) and the rotor bottom end (2101) to be located inside the rotor assembly; Alternatively, the second bearing (42) protrudes from the rotor bottom end (2101).

4. The brushless motor according to claim 3, characterized in that, Along the axial direction of the motor shaft, the height between the rotor top end and the rotor bottom end is the height D of the rotor assembly, and the distance between the second bearing (42) and the rotor bottom end (2101) is d, where d / D ≤ 0.

7.

5. The brushless motor according to claim 1, characterized in that, The rotor assembly (2) includes a rotor front end plate (221), a rotor rear end plate (222), and a rotor iron core (223). The rotor iron core (223) is located between the rotor front end plate (221) and the rotor rear end plate (222); The rotor front end plate (221) is recessed with a bearing seat cavity (2211) in the axial direction of the motor shaft (21); the bearing mounting portion (150) includes a second bearing seat (15) extending in a direction opposite to the direction in which the motor shaft (21) passes through. The second bearing seat (15) is located in the receiving cavity (11); the second bearing (42) is assembled in the second bearing seat (15) and, as a whole with the second bearing seat (15), is located in the bearing seat cavity (2211); And / or, the front cover (1) includes a front end (14) of the front cover through which the motor shaft (21) passes. The first bearing (41) is assembled in the front end (14) of the front cover; the front end (14) of the front cover serves as a connection head for the brushless motor (10) to connect with an external structure.

6. The brushless motor according to claim 5, wherein Both the rotor front end plate (221) and the rotor rear end plate (222) are penetrated by the motor shaft (21) and rotate synchronously; The rotor core (223) includes a recessed portion (2231) recessed axially along the motor shaft (21); the front rotor plate (221) includes a stud (2213) having the bearing seat cavity (2211); The stud (2213) is located within the recessed portion (2231) such that the rotor core (223) is located on the outer periphery of the stud (2213); the rotor core (223) is clamped by the front rotor plate (221) and the rear rotor plate (222).

7. The brushless motor according to claim 6, wherein, One of the stud (2213) and the recessed portion (2231) is provided with a clamping portion (2214), and the front rotor plate (221) and the rotor core (223) are clamped by the clamping portion (2214); and / or, one of the rear rotor plate (222) and the motor shaft (21) is provided with a clamping portion (211), and the rear rotor plate (222) and the motor shaft (21) are clamped by the clamping portion (211) to achieve synchronous rotation.

8. The brushless motor according to claim 1, characterized in that, The rotor assembly includes a recessed portion (2231) for reducing the weight of the rotor assembly (2); and / or, the stator assembly (3) surrounds the rotor assembly (2), or the rotor assembly (2) surrounds the stator assembly (3).

9. A brushless motor, characterized in that, The brushless motor includes a front cover (1), a rotor assembly (2), a stator assembly (3) and a bearing assembly (4), wherein: The front cover (1) includes a receiving cavity (11); The stator assembly (3) and the rotor assembly (2) are both located within the receiving cavity (11); the rotor assembly (2) includes a motor shaft (21); the motor shaft (21) passes through the front cover (1); The front cover (1) includes a bearing mounting portion, and the bearing assembly (4) includes a first bearing (41) and a second bearing (42); the first bearing (41) is assembled with the motor shaft (21) and the bearing mounting portion, the second bearing (42) is assembled with the motor shaft (21) and the stator assembly, and the height of the second bearing (42) at least partially overlaps with the height of the rotor assembly (2).

10. A cooking machine, characterized in that, The cooking machine includes the brushless motor (10) according to any one of claims 1 to 9, a mixing cup (20) and a cutter assembly (30). The front cover (1) of the brushless motor (10) includes a front end of the front cover (14) through which the motor shaft (21) extends. The front end of the front cover is assembled with the bottom of the mixing cup, and the motor shaft (21) is directly connected to the cutter assembly (30) to drive the cutter assembly (30) to rotate within the mixing cup (20); Alternatively, the cooking machine includes a main body (100) and a mixing cup assembly (200), and the mixing cup assembly (200) includes a mixing cup (20) and a knife assembly (30); the main body (100) includes the brushless motor (10) according to any one of claims 1 to 9; the front cover of the brushless motor (10) includes a front end (14) of the front cover for the motor shaft (21) to extend out, and the front end (14) of the front cover is assembled with the main body (100), and the brushless motor (10) drives the knife assembly (30) to rotate in the mixing cup (20).

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